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(preservation and access for american and british children's literature, - .) see http://purl.fcla.edu/fcla/dl/uf .jpg or http://purl.fcla.edu/fcla/dl/uf .pdf the world's fair or, children's prize gift book of the great exhibition of describing the beautiful inventions and manufactures exhibited therein; with pretty stories about the people who have made and sent them; and how they live when at home london: thomas dean and son , threadneedle-street, and ackermann and co. , strand. what a pretty picture we have in the first title page, of the great exhibition in hyde park! this gigantic structure is built of iron, glass, and wood; but as, at a distance, it seems to be made entirely of glass, it is called the "crystal palace." does it not look like one of those magnificent palaces we read about in fairy tales? the great exhibition is intended to receive and exhibit the most beautiful and most ingenious things from every country in the world, in order that everybody may become better known to each other than they have been, and be joined together in love and trade, like one great family; so that we may have no more wicked, terrible battles, such as there used to be long ago, when nobody cared who else was miserable, so that they themselves were comfortable. only look at the thousands of people who crowd the park,--all so different looking, and so curiously dressed. grave turks,--swarthy spaniards and italians,--east indian princes, glistening with gold and jewels,--clever french and german workmen, in blue cotton blouses,--chinese gentlemen,--tartars, russians, energetic americans, and many more. i wonder what they all think of us, whose habits in many things are so different from their own? and what charming things there are in the exhibition itself! fine porcelain wares, mirrors, books, statues, perfumes, and many more articles from various parts of the world,--beautiful fans, books, bronzes, and an infinity of other matters, from france in particular. here is a model in miniature of the crystal palace itself, in glass. ah! talking of glass, what think you of an enormous french decanter, in which three persons, having gotten inside by a ladder, can sit and dine off a table a yard in circumference? this is quite an exhibition in itself, i think. in another part of the building, we have a looking-glass, from germany, which is the largest that ever was made, and is encased in a splendid frame of dresden china. but here is a darling little english steam-engine, so small that you could, after wrapping it up in paper, lay it very comfortably inside an ordinary-sized walnut-shell, while the plate on which it stands is not bigger than a sixpence! in the very centre of the building, a gigantic crystal fountain diffuses a delicious coolness around, its bright clear waters sparkling, leaping, and playing, as if in delight and astonishment at the splendid and wonderful articles surrounding it. and there are two immense statues just beside it, looking mightily pleased with the agreeable coolness of the water. but here are two large bronze lions;--how terrible they look: they seem almost as if they were going to jump at us. there are animals of various kinds in different parts of the exhibition; stags, horses, foxes, birds, cats, and even a ferocious-looking tiger. there is a bundle of nails so diminutive you can hardly see them--another bundle of three thousand nails, one thousand gold, another silver, and the third iron; so light that the whole weighs only three grains,--a french watch, smaller than a fourpenny piece,--hindoo stuffs, so thin you can scarcely feel them, yet are made from rejected cotton-husks,--a highly-finished model of a palace, from italy; and a handsome carriage, from prussia. but among the curious articles we must notice this imitation of a camelia japonica tree in china, with buds, leaves, and blossoms, all perfect, which came from germany;--and that painted oil-cloth from manchester, covered with the most extraordinary mathematical ornaments, and which took eleven years to complete, and is worth guineas. and that table, made of , pieces of wood, of twenty-eight different colours, looking like mosaic, which was sent from switzerland. nor must we forget to look at this piece of gold, on which is engraved "the lord's prayer," and is yet so small that a common pin-head covers it: that came from portsmouth. and here is a german bed, which being wound up, like a clock, to a certain hour, throws the sleeper out on the ground, when the time comes; no lazy lie-a-beds with that, i fancy! but here is an odd contribution, also from germany; it is--what do you think?--a piece of lace, darned, and a fine table napkin, also darned! however, don't laugh, until i explain to you the reason _why_ it has been mended in this way: an ingenious young lady, wishing to show industrious lasses that torn clothes may be made to look as if they had not been injured in that manner at all, got a piece of cloth, tore it for the purpose, and taking up the stitches neatly, worked thread after thread till she had darned it in such a way that nobody could tell where it had been torn; she then thought of sending a specimen of her industry to the world's fair. here are snuff-boxes made of coal, which have been sent from woolwich; and a beautiful little cannon of agate, from germany; and two violins, worth a great deal of money, which have been contributed from america. i know that the productions of india will delight you by their beauty and ingenuity: the costumes the natives have sent are even prettier than those of turkey, spain, or persia, and their gold, silver, and mother-of-pearl ornaments, are enchanting; what splendid veils, dresses, shawls, carved ivory, and curiosities! i would have you look very attentively at the contributions from india, they are so gorgeous; such superb muslins, baskets, and fans; with silks, cotton, cocoa-nuts, roots, woods, and such tempting fruits. i always like to see indian articles, they are so magnificent. the persons who have sent these things must have worked very hard, to make so many beautiful specimens; but then the poorer people of india are exceedingly industrious; they live very simply, eating rice, boiled with milk and spices, as their principal food, for it is against their religion to touch meat of any kind. they would lead rather a sorry life, were it not that their tastes were so extremely simple, and their wants so few. a hindoo village looks more like a gipsy encampment, than anything else, and bears a very strange appearance to a european, at first. [illustration] however, although the poor people live in this way, the princes and nobles lead a far different life; an eastern grandee could formerly do anything he chose, even to killing of his wives and slaves, and, only i do not wish to frighten you, i could tell you many stories about the cruelty of the indian nobles. they live in great state, and are always surrounded by a throng of slaves, and attendants, who wait on them as they recline lazily on a pile of the softest cushions, which are covered with the skins of beasts, and with silks, velvets, and satins. when they go abroad they are carried in what is called a palanquin, borne on the shoulders of servants, if they do not choose to ride on a horse or an elephant. [illustration] their houses are adorned with the utmost magnificence, while the gardens or approaches to them are delightfully cool and refreshing, being shaded by fragrant trees, and shrubs, perfumed by the most beautiful flowers, and cooled by fountains, playing in marble basins. the indian machinery is very clumsy indeed, and the mills are the funniest-looking things imaginable: i must show you an oil-mill. [illustration] a very cruel custom prevails in many parts of india, which i know will shock you very much: when a hindoo of rank dies, his widow is laid by his side on a pile of faggots, which being set fire to, the poor creature is suffocated, or else burnt alive, and they pretend that she likes to be so destroyed. the ceremony is called a "suttee," and is conducted with great pomp, all the relations of the woman and her dead husband being present, in addition to an immense crowd; before getting on the pile, the widow divides all her jewels and ornaments amongst her friends. here is a picture of a widow about to bathe in a "consecrated" river, before going to be burnt. here are lovely specimens of the manufacture of gold, silver, silk, jewellery, and lebanon horns, from syria, with seeds, fruits, oils, and woods; and even ornaments and marble from jerusalem! little did the crusaders of old think, when they were fighting in jerusalem, and the holy land, that the infidels, as they very incorrectly called them, would be sending in such a friendly way to england. [illustration] what splendid caps, slippers, veils, and perfumes, with such picturesque guns and swords, from turkey! the turks are a fine, handsome race of people, and very grave and sensible, except when they are angry, when they grow raging and furious; they are fond of ease; and the chief delight of those who can afford it is to sit cross-legged on a low couch, drinking coffee, and smokeing a long curled pipe, called a _hookah_. they often sit by the side of a canal for a whole day, looking at children flying kites. instead of sitting at a table to dine, they put the dishes on a carpet of turkey leather, and sit round it on the floor, eating, with wooden spoons, meat and rice stewed together, called _pilau_. they are not allowed to drink wine, or eat pork. a favourite diversion with them is playing on a kind of lute, and sometimes they amuse themselves with chess, draughts, and other games; but their principal amusement, like some of my little friends, is to sit and listen to stories, told by men who earn their livelihood by relating entertaining tales and romances. [illustration] the turks do not undress and go to bed at any time, but being seated on a sofa, they smoke till they are sleepy, then laying themselves down, their slaves cover them over for the night. the poor people of the cities carry water, cakes, loaves, and other things, through the streets for a living, or act as buffoons, musicians, tumblers and wrestlers, at the sultan's and other of the rich people's palaces. they cannot use wheel carriages in turkey, the streets are so narrow, and the pavements in many parts so bad; everything is therefore carried by men, horses, mules, and donkeys, which is very inconvenient, as the mules and donkeys very often tumble down, and throw their burdens right in everybody's way; as for a horse, when heavily laden, it takes up the entire road; and when two loaded horses meet, the bawling and confusion is dreadful. the markets in turkey are called "bazaars," and there you can buy almost anything you want; and every trade keeps together in knots of shops, different from us, in particular quarters, so that you are not obliged to walk all over the bazaar in search of a hat or a pair of shoes. in these bazaars, it is customary for a dealer to ask much more than he means to take, and for a buyer to offer infinitely less than he means to give; it is, therefore, rather difficult to strike a bargain, and sometimes several days are occupied chaffering about a price. the turkish houses, above the ground floors, are usually built of thin laths, painted of different gay colours, and the roofs made of tiles, so that every few months a terrible fire takes place, and several thousand dwellings are burnt down; but the people are so accustomed to this that they do not mind it, and look on very contentedly while the fire rages, smoking their pipes, and drinking coffee. the turks are exceedingly charitable, and not only give alms to the sick and poor, but even to travellers and strangers; and some of them have exercised their benevolence so far that they have left a sum of money for digging wells, and for the support of several cats and dogs. a very great trade is carried on from many parts of the world with them, as their country is famous for its rich brocades, thick soft carpets, mattings, baskets, curiously-wrought gold and silver embroidery, and balsams. it is also remarkable for its attar of roses, spices, figs, and coffee; all very good things, i dare say, you will think. [illustration] some things have been sent from china to our exhibition; but the chinese people do not seem to care much about it. indeed, i wonder they sent at all, for they consider themselves as the only civilized nation in the world, and call china the "celestial empire," while they imagine that the emperor is an intimate relation of the sun, moon, and stars! they are a very industrious nation, however, and the emperor encourages them by his example. the poor work in every way they can; and one of their occupations is carrying about water for sale, as they have not water brought by pipes into the houses, as we have here. here is the picture of a chinese water carrier. [illustration] they also make the most elaborately carved ornaments, in wood and ivory; their toys and lanterns are celebrated for their ingenuity and workmanship. their fireworks are superior to all those of other nations; and they excel in tricks and amusing entertainments. the cultivation of tea is universal, and agriculture--which, you know is the art of tilling the earth--is held in high esteem; the principal products being rice, wheat, yams, potatoes, turnips, and cabbages. the dwellings of the peasantry too, are not in villages, as in old england, but are scattered through the country; and they have no fences, gates, or anything to guard against wild beasts, or robbers. the females raise silk-worms, spin cotton, manufacture woollen stuffs, and are the only weavers in the empire. the art of printing, though done in what i must confess is rather a clumsy manner, is much exercised amongst them, and gives employment to many people. i do not think we should like to dine with a chinese gentleman, or mandarin, as he would treat us to strange dainties, as--a roast dog, a dish of stewed worms, a rat pie; or, perhaps, a bird's-nest. but the bird's-nest would be the best of the list, for it is not like the kind of bird's-nests which you have seen, but is made, i believe, of the spawn of fish, and looks something like isinglass. it is the nest of a sort of swallow, is about the size of a goose's egg, and is found in caverns along the sea shores; so it is not so bad as it seems at first. and the rats are as large and fat as some of our rabbits, being fed on fruits and grain, purposely for eating; as also are their dogs, for eating. the people of the "celestial empire" are celebrated for their fondness for making beautiful gardens; but their houses and gardens are quite different from ours. what a pretty scene! what a delicious cool walk is formed by the grove of trees leading to the porcelain tower. and those ladies walking towards the boat,--or hobbling, more likely; for the chinese ladies have feet not much larger than your papa's thumb, which is there considered a great beauty. [illustration] the common women cannot afford to have little feet, as the feet of the rich girls are bandaged up in iron shoes, when they are two or three years old, to prevent their growing larger. these small feet are called "golden lilies;" but i am glad no such barbarous custom prevails in our own dear country. the chinese ladies, however, are extremely accomplished, and can play on many musical instruments, paint, and embroider. the merchants of china are not at all remarkable for their honesty, though a few of them are very scrupulous. many of them amass great fortunes. the chinese have sent in embroidered shawls, table-covers, teas, curious and intricate toys, and specimens of handicraft. [illustration] why, we have even specimens of russian industry, in the great exhibition; and very good specimens they are, too. russia is not such a pleasant country, in some respects, as any of those i have been telling you of; for in the winter the frost is so severe that many of the poor russians die from cold. the rich wrap themselves up in warm furs, and ride in fur-lined sledges, instead of the usual carriages; but the poor people are forced to continue working out of doors at their various employments, being very careful, however, to cover their legs, hands, and head with fur, lest they should be bitten with the frost, which sometimes seizes those parts and turns them white. though many of the poor women stand for hours together, washing their linen in holes cut in the ice, without getting frozen, yet it often happens that coachmen and other servants have been frozen to death in the streets at night, while waiting for their masters. at the end of every year, the russians keep a long fast, and as soon as it is over, lay in their store of winter's provisions, at a market held once a-year on the river neva, which is then frozen over. i should like you to see this market, it is so full of gaiety and singularity, while the high piles of frozen provisions look so picturesque along the ice. the russians are remarkable for their cheerfulness and contentment, and are so fond of singing, that they are always enjoying a song when at work. russian songs are very different from ours, and sound rather odd to us. the food of the common people is black rye bread, sometimes, by way of treat, stuffed with onions, carrots, or green corn, and seasoned with sweet oil. they use eggs, salt fish, bacon, and mushrooms, of which last they have a great plenty. the men are ordinarily dressed in loose trousers; short coats of sheep-skin, tied with a sash round their waists, and folds of flannel, fastened round with pack-thread, on their legs, for stockings. the women are dressed just as oddly, in short gowns, and with their hair plaited and hanging down their backs, if they are unmarried; or a cap and cotton kerchief round their heads, if they are married. the peasants' houses are built of wood, and have one or two rooms only; they are miserably furnished, with no beds, as the family sleep on benches in summer, while nearly one-fourth of the principal apartment is filled by an enormous stove, or rather oven, upon which they sleep in winter; for the smoke of which, there is no chimney beyond a hole in the wall. i don't think you or i would much like to spend a winter in russia. many useful things, you may observe, have come from spain--cheeses, honey, dried fruits, salt, lime, wool, oil, flax, and cotton; with guns, swords, and also beautiful ornaments; with some precious stones, diamonds, rubies, and emeralds. the spaniards are not either a very active or a very cleanly people, but they are exceedingly proud, honest, and hospitable; they are skilful workers in woollen and silk stuffs, and manufacture sword-blades of a very fine kind; while their leather is celebrated for its superiority. they also work beautifully in gold and silver; and trade in immense quantities of those oranges you like so well, lemons, citrons, grapes, raisins, olives, nuts, and wines. the chief amusement of both high and low is one which neither you nor i would be pleased with, i hope, for it is bull-fighting; which cruel entertainment they learned from the moors, who once had possession of spain, and built all the beautiful castles and palaces that are in it. the manners of the rich people are merely like those of our own gentry, but the common people are very peculiar; and all classes delight in playing on the guitar, and singing, both of which they perform charmingly. they have also two favourite dances, called a fandango, and a bolero, both extremely lively and graceful. the mode of conveyance in spain is by mules, and these beasts are surprisingly obedient to their masters, and answer to their own names just like our own pet dogs. the tails of the mules are oddly decorated, by cutting the hair into stars, flowers, and other fanciful designs. the villages are mostly mean, and the roads narrow; but madrid, the capital of spain, is a large city, with long, straight streets, many of them cooled by noble fountains. the houses in madrid are built of brick, and even the grandest of them have only lattices, instead of glass windows, most of which have, however, handsome balconies, supported on columns. in the churches, there are neither pews, benches, nor chairs; the ground is covered with matting, on which every one kneels together, from the grandee to the beggar. in the suburbs there are many woods of evergreen oak, vineyards, olive plantations, and orchards of mulberry, plum, and almond trees; and the flocks of black sheep and goats, grazing in the country meadows, have a pretty effect. i don't think you would find the spanish cookery much to your taste; for the spaniards are very fond of rancid butter in their meals, and of oil that has a very strong smell and flavour; indeed, when they are going to cook anything that requires fat, they lift down the lamp from the ceiling, and take out what oil they want. bread, steeped in oil, and occasionally seasoned with vinegar, is the common food of the country people. their favourite wine is that which has a strong taste of the leather bottles or casks, in which they keep it; and they will hardly eat any thing that has not saffron, pimento, or garlic, in it. they have, however, even amongst the poorest, such fine grapes, ripe melons, and tempting oranges, as my little readers, i know, have seldom tasted. in summer, they use a quantity of ice, which is sold in glasses, in the streets, for a trifling sum. in place of candles, the poor people have a piece of cane, cut with holes through it, which is fixed to the ceiling, and from one of the holes a lamp is hung by a hook. [illustration] the dress of the lower orders is very pretty indeed, and they themselves are mostly tall and handsome, with black hair and eyes, and dark sun-burnt complexions. the climate is so warm and balmy, that they can grow their fruits in the open air. some pretty articles have been sent from portugal, a country which is near spain, and very like it in all respects. it is a very fine country, famous for wine, and oil; and the sheep are much prized for their superior wool. the ladies of rank still spin flax from a distaff, to show their industry. the peasantry are not very well off; their only luxury is tobacco, and their usual fare is bread, made of indian corn, with a salted pilchard, or a head of garlic, to give it a relish. they are polite and hospitable; but the people of the towns have not the least scruple in stabbing any body that offends them; so that it is a dangerous thing to affront them. what elegant tables, pictures, vases, marbles, statues, shells, woods, and perfumes, have been contributed to the exhibition from italy. here is a table of a most beautiful material, called pietra dura, which took one hundred and twenty years to finish, and came from naples. italy has always been celebrated for the beauty of the articles manufactured there; and the things it has sent us now are certainly worthy of its fame. it is one of the loveliest countries in the world, in the spring and autumn, and is ornamented with the richest foliage; vines, mulberry, olive, and orange trees; and with high hills and deep dales, towns, villas, and villages. the soil is extremely fertile, and produces abundance of grain, the finest fruits and vegetables, with flax, saffron, and manna. the climate is delightful, except in summer, when the weather is dreadfully hot, and the winters are so mild, that ice and snow are quite rarities, except in the mountains; i wonder what my little-boy friends would do there, for a skate on the ice, or a merry game of snow-balls? rome, the capital of italy, is a splendid city, full of the remains of ancient temples, pillars, arches, and fountains; but many of them sadly ruinous and decayed. there are a great many jews in it, who are forced to live in a particular part, called the _ghetto_, which means a place for jews. the city of rome and the surrounding country are very unwholesome during summer, in consequence of the land not being properly drained, as it used to be in the times of the ancient romans, so that it is dangerous to dwell near them at that season of the year. the numerous vineyards in italy, are not divided by hedges, but by rows of rather fine trees, the vines clinging in graceful festoons from one bough to another. in some parts of the country, there are various picturesque corn fields and meadows, bordered by olive trees. the italians are not a very industrious people, but they make silk stockings, soap, snuff-boxes of the lava of mount vesuvius, tables of marble, and ornaments of shells, besides gloves and caps of the filaments of a kind of muscle, which they get off the rocks, where it fixes itself by spinning a web from its own body, like the silk-worm or spider. these caps and gloves are actually warmer than those made of wool, and are of a fine glossy green colour. [illustration] there are a great many beggars, i am sorry to say, in fair italy, who are called _lazzaroni_, and they live on whatever they can get, sleeping under porticos, piazzas, or any place they can find, and are, as you may guess, excessively idle, like all other beggars. there are also hordes of thieves, who are called _banditti_, and who rob people in the most daring manner, for there are very few police. but there are also numerous persons who are quite well-behaved, and do all they can to earn their bread honestly. among these is a set of men called _improvisatori_, who tell stories, or repeat verses in the streets, and get a good deal of money from those who stop to listen to them. it must be very pleasant, on a cool summer evening, to sit under some magnificent old portico, listening to some interesting poem, or hearing a pretty story related. throughout italy, one of the remarkable customs, is keeping of a grand festival, which begins some weeks before lent, and is called the "carnival;" on this occasion, every place is brilliantly adorned, and the people go about singing, dancing, joking, and masquerading. the most splendid carnival is kept at venice, a remarkable city of italy, built upon a several islands, the sea, which runs every where among them, serving the inhabitants for streets. the italians are very handsome, and have jet black hair, dark roguish eyes, and fine figures. the dress of the lower orders is even prettier than the pretty spanish costume. the men wear high-crowned hats, such as you may sometimes have seen on the organ-grinders in the streets of london, velveteen jackets, gaiters, and open shirt-collars, loosely fastened by a silk ribbon; while the women have short scarlet petticoats, and jackets of a darker colour, with exceedingly short sleeves, tied with bright ribbon, and their long black hair decorated with coloured bows of ribbon, and confined by a silk lace net, which falls partly over their shoulders. instead of sending thieves to prison in italy, they are sent on board the galleys, a large kind of rowing vessels, where they are chained to the decks, and obliged to endure every species of hardship. what a number of things the germans have contributed! bracelets, articles of straw, beautiful household furniture, toys, wire, and many other manufactures. here is a splendid tray of polished amber, with a little carriage, made according to a proper model, and a large chandelier of amber, capable of holding several thousand lights. there is a beautiful cabinet made of a collection of pieces of unpolished amber, intended to show the different kinds of that mineral, its various forms, its peculiarities, and its varieties. here is a bedstead, worth it is said ten thousand pounds; and the most elegant furniture ever seen. and here is a piece of white silk embroidered with portraits of our queen and the prince of wales, done in a thin kind of thread, called "hair thread." you know a good deal about germany itself, i dare say, already; but i must tell you something about the germans themselves. they are grave and thoughtful, but highly romantic and full of enthusiasm. their love for their country is most remarkable. all classes in germany are well-educated, and many painters, poets, and musicians, have been born among them. the art of printing was first practiced in that country, and at present the number of books printed there is immense; while every year a book-fair is held at the city of leipzig. the produce and manufactures of germany are exceedingly numerous, and you see they are of great variety, such as clocks, watches, woollens, linens, toys, wines, ornamental work in iron and steel, worsteds, and silks. in the public walks and gardens, on sundays, the people assemble in great crowds, dressed out in their holiday clothes, while ladies and gentlemen walk about without the least restraint among the working people. the chase is a favourite amusement with the nobles and gentlemen, and is a sport in which they are lustily joined by the peasantry. the immense forests with which the country abounds gives shelter to wild boars, wolves, and many other ferocious animals. on grand occasions there is held what is called a _battue_, when a number of deer are driven into an enclourse, and shot at by the sportsmen. the habits of the peasants are extremely simple, but the people are industrious and ingenious. the villages and cottages are neat and comfortable. the peasants make many pretty toys and ornaments, and bring provisions to market from a great distance, in light roomy wheel-barrows, made for the purpose. the german people are in general fair, with blue eyes, flaxen hair, and full figures; but they do not wear any very peculiar dress. in models of ships, in rosewood furniture, in silver embroidery, and silver cups,--besides linens, calicoes, and glass beautifully painted for windows; many contributions have been sent in by the dutch. there are also soft thick blankets with scarlet borders, which make one warm merely to look at them. the dutch people are industrious, and cleanly. the women are the most active and nicest house-wives in the world; they scour and brighten, and rub not only the furniture and inside of their houses, but the outside as well; the houses in holland, by-the-bye, look like painted baby-houses, and are roofed with glossy delft tiles, and the rooms are lined with smooth square tiles of delft, and the floors paved with marble. the people are never idle in holland, but are always working at a great variety of manufactures, among which are leather, woollen, and linen articles,--also, paper, wax, starch, pottery, and tiles. large quantities of gin are likewise made, and this liquor is in england called "hollands" for that reason. carts are not much used by the dutch; their goods are carried on sledges, very light waggons, and boats. the reason of this is, that they are afraid lest the wheels of vehicles should injure the foundations of their cities, which are generally built on piles of huge trees, driven like stakes into the bog beneath. the common people are very humane to their cattle; they rub down the cows and oxen, and keep them as clean and sleek as our english horses. canals run through the principal streets, and in winter they are frozen over for two or three months, when the whole country is like a fair; booths are erected upon the ice, with fires in them. the country people skate to market, with milk and vegetables; and every kind of sport is seen on the frozen canals. sledges fly from one street to another, gaily decorated, and numberless skaters glide about with astonishing swiftness and dexterity. no people skate so well as the dutch. [illustration] holland was once a quagmire, almost covered with water; but by making canals higher than the land, and pumping the water out of the fields into them, the land was drained. the bogs are numerous, and supply so much turf that little else is burned. there are no beggars; and the people are in general pretty warmly clothed, and comfortable looking, with ruddy faces. the townspeople are dressed almost like the londoners, or parisians; but the costume of the country folks is rather funny. a farmer's wife, when out for a holiday, wears a large kind of gipsy hat, like a small umbrella, lined with damask; a close jacket with long flaps; and full short thick coloured petticoats. her slippers are yellow, her stockings blue, and her cap is without a border, being made to fit her head exactly, and gaily ornamented with gold filagree clasps; while her costume is finished by a pair of earrings and a necklace. the farmer himself wears a hat without a rim, and huge silver buttons on his coat; and keeps whiffing away at his pipe, which he is seldom without. the dutch are most excellent gardeners, though they sometimes ruin themselves by their love for flowers. among the articles that have been sent here from switzerland, are several well worth looking at, they are so wonderfully ingenious. of this kind are two boxes, one of white wood, and the other of brown; the white has a lovely alpine rose, with garlands of flowers upon the sides, the rose and lid being cut out of one piece of wood, and so beautifully made to imitate nature, that the slightest touch with the point of a knife or a needle, makes the leaves move and quiver without spoiling the flower. this was made by a swiss peasant. the people of switzerland are very remarkable for their industry, contentment, and ingenuity. among the villagers, their chief occupations are the management of dairies, and the breeding of cattle; and many of the peasantry make a living by hunting the chamois, as the wild goat is called. this is rather a dangerous employment, yet the chamois-hunters delight in it; they carry a long hook pointed with an iron spike, and with the help of this, they leap from rock to rock, over frightful chasms and precipices; yet such is their surprising activity, that they are never killed. other peasants earn a livelihood by fattening and preparing snails for market; for these creatures are considered a great delicacy in many parts of switzerland. in another part of the country the inhabitants almost exclusively follow the trade of watch-making, and polishing the crystals and pebbles that are found in the mountains, geneva, a city of switzerland, is celebrated for the watches that are made there. the women are extremely domestic, delighting in their children; and all the swiss are remarkable for their passionate love of home. in every village there is a school, established by the government for the instruction of poor children. the swiss are the most graceful of all peasants, and wear very smart costumes. the men wear large hats, and their dress is generally a brown cloth jacket without sleeves, and puffed breeches of ticking. the women have short blue petticoats, a cherry-coloured boddice, full white sleeves fastened above the elbow, and a muslin kerchief thrown round their necks; while their hair is plaited, and twisted about their heads. they also wear pretty flat straw hats, ornamented with bows of ribbon. the scenery of switzerland is of the most charming and romantic description; there are towering mountains, craggy rocks, steep precipices, with foaming torrents dashing down their sides, and dizzy heights, which i should be sorry any of my little friends were looking down. but these are delightfully intermixed with beautiful valleys, adorned with groves of fir, beech, and chestnut trees; clear lakes, rapid rivers, cataracts, and bridges of one arch reaching an immense distance from rock to rock. portions of the mountains are covered with villages and scattered cottages; and the inside of the dwellings are so neat and look so comfortable, that you could almost wish to live in one of them, if you were not told that there is a perpetual danger of their being buried under one of the enormous masses of snow that frequently roll from the tops of the mountains, and destroy everything in their way. these masses are called avalanches. between the summits of the highest of the mountains are valleys of ice, frozen into many fantastic shapes, formed by one crust of ice growing hard over another; but what is more extraordinary, is that the borders of these glaciers, as they are called, are fertile: strawberries, wild cherries, nuts, barberries, and mulberries, grow there; and goats browse on the most inaccessible parts of the rocks, and bound with the most surprising agility from one cliff to another. [illustration] several contributions have been sent by the prussians and austrians; woollens, minerals, linens, china, and other things. the prussians are a very polite and well-educated people, and nowhere are there more schools than in their country. prussia itself is an extremely pleasant place, and the towns are fine, with wide, regular streets, and high antique-looking houses; the streets are mostly lined with trees, which look pretty enough while their leaves are green, but rather prevent the free circulation of air. the prussian ladies delight in fine clothes, and would be much vexed if they were obliged to go out without them. the gentry speak french, but the common people talk german. the beautiful dresden china we see at the exhibition, cames from the town of dresden. austria is a very fine country, and contains a great variety of people. the principal artizans are tanners, furriers, boot makers, lace workers, and cabinet makers. there are also workers in iron, copper, alum, saltpetre, besides many others. the general habits of the austrians are like those of the germans, so i do not think i need tell you anything about them. the poles and hungarians have also sent their industrial productions to the great exhibition; cloth, lace, furniture, brooms, linens, woollens, and other articles. i dare say you have heard a good deal lately about the hungarians, when they were fighting against the austrians and russians. the hungarian peasants are very hard-working; indeed, they cannot help being so, for as the nobility and gentry are not taxed, the poor people are forced to pay all the taxes, besides being obliged to give money and provisions to their masters, the lords of the manor, who, i am sorry to say, are excessively tyrannical. they are also compelled to pay tithes to the clergy, the magistrates, and the soldiers, and to work for nothing on the public works; against which bad laws they fought. agriculture, and the breeding of cattle, are carried on to a considerable extent. hungary is occupied by a variety of people, with entirely different habits; it contains frenchmen, sclavonians, turks, jews, spaniards, gipsies, germans, and greeks. the magyar language, the original hungarian tongue, is spoken by the peasants; but in the cities the people mostly use german and french. the poles live in a cold, flat, marshy country, in the north of europe. the peasantry are in a miserable state, very dirty and frequently drunken; and their land is in a wretched condition. the swedish and danish people have made many things to be exhibited in the world's fair. sweden is in the north of europe, and the climate is very disagreeable, for it is extremely cold in winter, and intolerably hot in summer. the people do not live very luxuriantly; their bread is not only black and coarse, but so hard that they are sometimes obliged to break it with a hatchet; and this, with dried fish, and salt meat, forms the chief part of their food. yet they are very hardy and contented. at michaelmas, they kill their cattle and salt them, for the winter and spring. their favourite drink is beer, and they delight in malt spirits; some of them have tea and coffee. their houses are generally built of wood, and their cottages are made of rough logs; the roofs are covered with turf, on which the goats browse. the swedish women do everything that men are employed to do in other countries; they plough, sow, and thresh, and work with the bricklayers; the country women, as well as the ladies, wear veils to shade their faces from the glare of the snow in winter, and from the scorching rays of the sun reflected from the barren rocks in summer. [illustration] the iron mines of sweden are exceedingly useful; they furnish great quantities of metal, to be exported to england, for the use of our steel manufactories. the extensive forests supply numerous pine trees, which are cut down and sent to foreign countries, for ship and house building; while pitch and tar are made from the sap,--a preparation which gives employment to many of the inhabitants. the swedes contrive to make things from materials we should throw away as good for nothing; they twist rope from hogs'-bristles, horses' manes, and the bark of trees; and form bridles of eel-skins. the coarse cloth they wear they make themselves, for the women are continually busy spinning or weaving. sweden is the birth-place of the famous botanist, linnæus, and the charming singer, jenny lind. norway is united to sweden, but it is still colder in winter and hotter in summer. the people live very simply, mostly on milk, cheese, and dried fish; and sometimes they have slices of meat, sprinkled with salt and dried in the wind. in some parts of the country, the people make bread of the bark of the pine tree; and in winter, for want of hay, they are obliged to feed their cattle on dried fish. the houses are built of wood, and many of the roads are made of the same material; while wooden fences are used instead of hedges. the norwegians send metals, minerals, salt, butter, dried fish, and furs, to other countries. denmark is a very fine country, perfectly level, except a single ridge of mountains. its chief products are grain, tobacco, flax, madder, and hops. there are a great many mines, but few manufactures carried on; though the danish gloves are much esteemed. the climate is generally rather warm, but very wet. the danes are mostly well-educated; they are like the swedes in their manners and customs. they have sent many specimens of their industry to the great exhibition. [illustration] why, who would have thought of seeing persian and egyptian contributions at the exhibition? and such splendid articles as they are! persia, you know, is a rich and fertile country, near russia, in asia; but although it has many beautiful flowers and fruits, yet is there very little timber; owing to which they have no shipping. the persians delight in fine clothes on which they lavish the greater part of their money, and they are fonder of scarlet, or crimson, than of any other colour. they are very skilful in dyeing, in making silks, shagreen, morocco, gold and silver ornaments; and they form excellent swords and weapons. their commerce with turkey, china, arabia, and other places, is carried on by means of what they call "caravans," which are large companies of merchants, who travel together for the sake of security from thieves, by whom however, they are often robbed; these companies have frequently more than a thousand camels, to carry their luggage and their goods; and in consequence of the excessive heat, they are obliged to journey mostly in the early morning, and rest during the day. the persians live chiefly on rice, fruit, and coffee, and eat very little meat; they luxuriate in baths, and the poorest amongst them endeavour to have a horse. they use the turkish language, and are nearly all mahometans; they used to worship the sun and fire, though very few continue to do so still. the persian ladies never appear in the streets or any other public place, without having long veils, in order to conceal their faces, as the turkish ladies do. the persians are very like the turks in their manners and customs, which i described to you before. egypt was, formerly, a mighty empire, and had rich and haughty kings, who adorned it with magnificent temples and palaces. i dare say you remember what you have read of it in the history of joseph and his brethren, and in that of moses. it was here that solomon built his magnificent and gorgeous temple. it is now, however, an exceedingly mean country, and is governed by a turkish pacha, whose grandfather contrived to make himself master of egypt, as well as of syria and palestine. the climate of egypt is excessively hot,--in fact, the nights in spring are the only pleasant part of the year. the nights in autumn are also very fine,--even delicious; and the rays of the moon are so bright that the natives, who sleep in the open air, cover their eyes to prevent their being injured by the brilliancy. the greater portion of the land is covered with burning sands; but wherever the waters of the river nile have been conducted by canals, and allowed to flow over the country, the earth becomes fertile, and fruits thrive luxuriantly. there are but few garden flowers, but roses are extensively cultivated, the attar of roses forming an article of commerce. there are many valuable minerals found in the earth; and beautiful marble, alabaster, salt, alum, and other useful things. the woods, marshes, plains, and rivers supply a variety of animals, most of them wild and ferocious. it was in egypt that the hippopotamus was found. the people devote themselves to agriculture, the rearing of bees, and poultry; they also carry on an important trade with other countries. most of the egyptians are strong, of a tawny complexion, and of a gay disposition. they luxuriate in water; and esteem it the height of enjoyment to sit by a fountain, smoking their pipes; they are excessively fond of bathing. cairo, the capital of egypt, is a large city, with irregular unpaved streets, and brick houses, with flat roofs. there are a good many small manufactories; and some schools, a printing-office, and a large library. there are numerous magnificent fountains in the city, which are indispensable on account of the intense heat; and more than a thousand shops for selling cups of coffee, of which the egyptians are very fond; these coffee shops are called _rahwehs_. all along the river nile the banks show signs of industry; cotton, tobacco, and other produce being grown down to the water's edge. the pyramids of egypt, the time of the building of which is not known, are considered one of the wonders of the world. * * * * * the greeks have sent some fine stuffs; their silk manufactures are really beautiful, and their sculptures and feather-fans are splendid. greece was a famous country long, long ago, in ancient history, but it has undergone many sad changes, and was for a long time ruled by the turks. the english, french, and russians rid it from turkish hands; but its present government is weak and imperfect, for the numerous petty chiefs pursue a wicked system of robbery, fighting, and tyranny. indeed, many of these chiefs have fitted out vessels as pirate ships, in order to seize and plunder any other vessels weaker than their own with which they may fall in. there are, however, many wealthy greek merchants; and a number of rich jews live in various parts of greece. the greek people are beautiful and graceful. the women have fine oval faces, their eyes are large and dark, their eyebrows and hair are of deep shining black, and their complexions are mostly pale. they are very splendid in their dresses; the costume of the men is extremely like that of the turks. from having been so long subject, however, to their turkish rulers, the greeks have become artful and cunning. the rich ladies and nobles of greece have fine young slaves to wait upon them, and amuse them by singing or dancing. these slaves are bought from the tartars, who steal them from russia, circassia, or georgia, and are taken great care of, being taught to embroider, sing, dance, and deport themselves with elegance and grace. their masters or mistresses scarcely ever sell them, but when they are tired of them, either give them to a friend, or set them free. when they do sell them, it is as a punishment for some crime, or for being useless. there are numerous brigands, or thieves, in greece, who are divided into bands, and rob with the utmost impunity. they manage to hide themselves very artfully in the roads where they expect to meet travellers, doubling their bodies up behind stones and bushes, or else lying flat on their faces on the ground, when they suddenly all start up and surround any unfortunate individual who may happen to pass that way. there are also honest, industrious people in greece; and among them are the guides, men who show strangers over the curious portions of the cities for a trifling sum of money; and there are the cabmen of athens, who are usually very intelligent and well-informed; there are a number of cabs in athens. the greek houses have only one story; but there are generally large gardens, carefully tended, attached to them. the climate is generally mild, but not so much so as formerly, on account of the cutting down of the forests. the spring and autumn are delightful; but the summer is too hot, and the winter is almost a succession of storm and rain. the earth is extremely fertile, and produces corn, wine, and fruits, besides the honey and figs you like so much. the people manufacture silks and cottons, and export quantities of small raisins, which grow very luxuriantly in and about the city of corinth. corinth is one of the most charming places that you can fancy to yourself, and is surrounded by beautiful views and the remains of ancient temples, columns, and statues; groves of fine olive trees border the city, and the waters of two bays meet near the entrance. the ruins of the ancient temples and buildings in athens, the capital of greece, are still to be seen; but so little do the ignorant and foolish people, who have lived in the city in modern times, value these great works, that they have for hundreds of years used the greater part of the splendid marbles to build their houses, which are only ordinary and common-looking. [illustration] the inhabitants of bavaria and belgium have sent almost numberless articles of industry to the exhibition; furs, lace, machinery, corn, books, furniture, and metals. belgium was formerly called flanders, and the people produced superior cloth, hats, cutlery, and other useful things, a very great many years before the english could make any thing better than the most common sort of goods. the belgians are still celebrated for their ingenuity in making toys, lace, cloth, silk, satin, velvet, and other useful articles. they are also famous for the culture of flowers, in which they excel even the dutch. every house has a garden attached, which is frequently surrounded by a moat. the country is small, but every part of the land is made fertile by the industry of the farmers, of whom there are a great number; many of them grow flax, which is woven into linen by the women. there is a weekly market for linen, held at ghent, whither the peasantry carry their products for sale, and both men and women may be seen standing in two long lines, with benches before them. the farms in belgium are cultivated with great care and attention, and much resemble the market gardens round london; they all have gardens, and grow an ample supply of fruit and vegetables. the food of the peasants, is rye-bread and milk, for breakfast and supper; potatoes and onions, with bacon and beer, for dinner; they eat off pewter; and although their fare is simple, it is good and plentiful. their dress is somewhat coarse, but it is neat and clean, the men wear blue linen frocks; and the women have printed cotton gowns, linen caps, and woollen petticoats. the towns and villages of belgium are numerous, and thickly peopled. brussels, the capital, is a fine city, and is celebrated for its manufactures, particularly for lace, camlet, and carpets. ten thousand people are employed there in making lace. it is also famous for its pottery and porcelain. the other articles made there, are cotton and woollen stuffs, silk stockings, and earthenware. the carriages built there, are superior to even those of london or paris; there is a specimen of belgian carriages at the exhibition. there are numerous silk manufactories in brussels; and the beautiful linen, called damask, is exported in great quantities. there are innumerable breweries, too; for no people in the world are so fond of drinking beer as the belgians. the people carry on a considerable trade with foreign countries, by means of the various canals, on which a vast number of steam-boats are constantly passing and re-passing. the upper part of brussels is magnificent, and has a splendid park laid out with shaded walks, and surrounded by the palaces, private houses, and public offices; but in the lower part, the streets are narrow and crowded, though the market-place is very beautiful. there are twenty superb fountains in the city, ornamented with sculpture. the belgians delight in music, and they hold musical festivals every year. in the horticultural gardens at ghent, during summer, there are several concerts performed in the open air; and even among the labouring people, the songs and pieces of music sung together by groups of peasants and working people are often delightful to hear; for in belgium, as in holland, prussia, and over a great part of germany, even the poorest children are freely taught to sing in harmony at school. there are several railways in belgium, which is a very great convenience to travellers. the climate is good; and, in winter, snow does not fall deeply. bavaria is in germany also, and is celebrated for its manufactures of iron, glass, paper, hardware, clocks, linen, woollen, and fire-arms. the people are industrious and careful, excepting in smoking tobacco, of which they are very wasteful. industry is encouraged; and several schools have been established for teaching young men agriculture and gardening, with the usual branches of education. [illustration] we must not forget to see what has come from america. our great exhibition has been almost as much talked of there, as it has been at home, and an immense number of contributions has been sent from that country. machinery, sculptures, stuffs, carriages, minerals, boots and shoes, iron-work, and wines, have been dispatched over to the exhibition. america was formerly inhabited by numerous tribes of red indians,--a wild, warlike race,--of whom but few now remain, and those not at all civilized; but the greater number of the white people of america are the same in their dress, manners, and language, as ourselves. a large portion of america is called the united states, which is a republic; that is, it is governed by the people themselves, without a king, queen, and a royal family; they appoint a president every four years. long ago, the united states belonged to the english, but the natives gradually grew more powerful than they had been, and threw off all foreign control. america produces every kind of grain and fruit, as well as spices, dye-woods, and balsams. the people export quantities of natural productions to europe, but their manufacturers are not as yet able to compete with those of what are called the _old_ countries. the principal manufactures are of cotton, woollen, iron, and leather; which they exchange with the red indians for prepared bark, skins, and birds' feathers. mines abound, particularly for gold and silver; and there is abundance of precious stones. the farmers are a very industrious and intelligent class, and display much taste and neatness in their management. the finest timber for ship-building is abundant, and easily obtained; and there are many excellent harbours. numerous fishing stations are situated along the coasts, and are very valuable; for fishing is there a very good employment, and engages many of the natives of the northern states. as these fishermen get accustomed to a sea-faring life, and inured to fatigue, they soon become excellent sailors, and furnish men for the navy. [illustration] the whale fishery is also a valuable pursuit, but it requires uncommon bravery and skill.--in the united states there are numerous schools and academies, wherein the children are educated free. the rich people in america are free from haughtiness, awkwardness, or formality, but they do not display the elegance and refinement of the higher classes in england or france. as for the common people, they are serious, shrewd, and industrious; but often seem rude and uncourtly to strangers, for they wish to show their independance by an annoying surliness of behaviour. a great number of turnpike roads, railways, canals, and bridges, have been formed, and improve the country very much, as you may imagine. the americans make works in iron and wood, articles of machinery and of husbandry, tanned leather, and dressed skins. they are famous for ship-building. [illustration] peru, which is in south america, is a very fine country, and produces many useful things, such as tobacco, pepper, jalap, peruvian bark, and indigo. there are numerous valuable gold and silver mines, which make the inhabitants so rich, that at one time, long since, they paved several streets with ingots of silver, in proof of their wealth. there are whale fisheries on the coasts. only _one_ specimen of industry has been sent from peru! [illustration] mexico is another portion of south america. its products are numerous, but the country suffers much for want of water, though the dew falls heavily every night. the soil is rich, and well cultivated, although not so carefully as with us. indian corn is the principal food of the natives, and is cultivated so generally, that when the crop fails, there is a year of famine. a drink is also made from it, called chicha. sweet potatoes, yams, and quantities of red pepper, together with vegetables, and fruits, and tobacco, are grown. a kind of plant, called a cacao, is so highly prized that the grains are used for money. for want of streams, of which the country is sadly deficient, the mills are mostly worked by animals, and are very inferior; and the machinery is so bad, that the cotton is separated from the seed by the hands of workpeople. the principal manufactures are cigars, cottons, soap, tanned leather, gunpowder, pottery, and hats. the rich people use a number of silver vessels, and a quantity of plate, on account of the want of manufactures of china and glass, so that the trade of a silversmith is rather good. boots, saddles, and coaches, are well made: but the furniture, which is mostly of pine and cedar, is coarsely and clumsily put together. the streets of mexico are rather wide and well paved; the houses are ornamental, and the churches and public buildings are magnificent.--the rich people pass the greater part of the day on their sofas, in darkened rooms; but in the evening, they appear arrayed in the most elegant costume, for they are particularly partial to parties and brilliant assemblies. [illustration] there are numerous beggars, called leperos, who are very drunken and dishonest; but lively, voluble, and extremely civil; though they will pick any body's pocket. there are also innumerable indians, who make earthen pots very neatly, and use them instead of iron or copper vessels. you have heard of canada, which is a part of north america, and all that now remains to england of her vast american colonies.--well, we have an enormous canoe from canada!--i wonder who can have sent that? a canoe, as you know, is a kind of boat, which uncivilized people, who live near rivers, use. the canoes of canada are of a very thin material, and so light, that the boatmen, in passing overland from one river to another, generally carry them on their heads. the canoes are mostly covered with bark, the pieces of which are sewed together with a particular kind of grass; the bark being usually not more than a quarter of an inch in thickness. the people of canada, who are called canadians, are rather industrious; they make very fine fans, they hunt, fish, and collect sugar from a tree called the sugar maple. their houses are built of stone, and are plastered, but seldom are higher than one story, except in the towns, and are made very warm by means of stoves. the furniture is usually made by the canadians themselves, and is exceedingly simple. the chief article of food is peas soup, with a small piece of pork boiled in it, and a dish of thick sour milk. the women and children scarcely ever drink other than milk and water, but the men are particularly fond of rum. winter lasts six months, during which time the greater part of the day is devoted to amusement, principally dancing. most of the women can read and write, but the men can hardly do either; and the manners of both are very gay and light. there are a few lead mines in canada, in which silver is also found. their exports are timber, furs, potash, grain, and pearl-ash. [illustration] australia has also sent her contributions to the exhibition. among them are specimens of the skins of animals, dried plants, fine woods, and other things. in australia, there are scarcely any extensive manufactures, but the natives make some useful things, from the various and curious trees which abound. for instance, they form the most durable furniture and weapons from the casuarina or club tree; they make cloth from the finest bark of the paper-mulberry tree, and cord from a peculiar kind of flax. there are sago and cocoa trees, which grow to the height of one hundred and fifty feet, and are thirty feet round. figs, lemons, oranges, sugar-canes, gum-trees, bread-fruit, and a kind of pepper, from which a drink, called ava, is made, are very useful to the natives. there are mines of a very rich quality, but they are as yet scarcely attended to. the original natives are very idle, and not very well off; those who live near the sea shore, catch fish; and those in the woods, eat such animals as they can get; or climb up trees, for honey, squirrels, and opussums. [illustration] the settlers, who are the people who have gone out from england and other countries, to dwell there, live in a very comfortable manner; they have large farms, with flocks of sheep and herds cattle, fields of waving corn, rice, and wheat; pretty huts, or shanties, as they are called, and a profusion of the most beautiful plants and creepers. in some parts of the country there are thriving towns, with good streets, elegant shops, and fine houses, such as there are in london. [illustration] from the west indies, specimens of industry have also come. rice, fruits, sugar, metals, and plants, are among the contributions. the west indians send us sugar rice, currants, raisins, cloves, nutmegs, cinnamon, allspice, and mace, for puddings; nice nuts, for our little boys and girls; coffee, cocoa, and chocolate, for our breakfast and tea; and fine silk, and cotton, for our dresses. under the name of the west indies, there are many countries:--cuba, jamaica, hayti, porto rico, barbadoes, and others. in cuba, are found mines of gold, copper, and different other metals; there is a quantity of sugar grown there; and the tobacco is finer than that of most other islands. the trees are principally ebony, cedar, and mahogany, which are hewed down, and sent to foreign countries, to be made into furniture of various sorts. cedar wood is also used to scent clothes and papers, on account of its sweet perfume. the cubans are fond of bull-fighting, and of cock-fighting, i am sorry to say. balls and parties are also a favourite and more innocent amusement. in jamaica, the principal exercise of industry is in growing sugar, indigo, coffee, and ginger. these are cultivated in what are called plantations, which are attended to by negroes, who used to be slaves, and used to be lashed on to work unnaturally hard with whips; but they are now free in all the british colonies, as i hope they will be every where, long before any of my little friends, who read this book, may die. for not only were men and women kept in a state of slavery, but all their dear innocent little children, both little boys and little girls were treated as slaves. the bread-fruit tree is one of the most useful productions of the country, it not only supplies food, but other necessaries. of the inner bark is formed a kind of cloth; the wood, which is soft, smooth, and of a yellowish colour, serves for the building of boats and houses; the leaves are used for wrapping up food; some parts of the flowers are good tinder; and the juice, when boiled with cocoa-nut oil, is employed for making bird-lime, and as a cement for mending earthenware vessels. so you may guess how useful it is to the people of jamaica, and yet it is not a native of the west indies, but was first brought there by english people, within the last seventy or eighty years. hayti is now a much more flourishing island than it was; the emperor, faustin soulouque, does every thing in his power to render it a civilized and polite country. he encourages all the arts and industrial sciences; and, in his court is kept up the grandeur of a great and powerful state; though the haytians are black people, and were for the greater part negro slaves. barbadoes is an exceedingly warm country, and is unfortunately liable to dreadful hurricanes, which sometimes overthrow whole towns and villages. the products are sugar, cotton, ginger, and rum. the tall sugar-canes, which grow as high as five or six feet, are set in plantations and tended by negroes; and the cotton plants are also taken care of by the negroes, who are almost the only persons who can work in the open air, on account of the heat. the houses of the planters are numerous all over the country; and, with the green hills, and the luxuriance of the vegetation, make an extremely picturesque scene. since slavery has been abolished in our west india islands, schools for the children, and chapels for religious worship, have been erected at the expense of the negroes; numbers of whom have also become small landowners. [illustration] what a number of specimens have been despatched to the exhibition from algeria, tunis, and the cape of good hope: one, a model of a winged head, moulded in fine yellow clay, is really pretty; and the preserved fruits have quite a tempting look. and here are some boxes, made of most brilliant fancy woods; a few knives, soaps, cigars, herbs, and specimens of various woods, in blocks and in polished pieces. here is also opium, paper made from the palm-tree, articles manufactured from native woods, with essences, perfumes, and splendid veils, slippers, caps, guns, and swords. algeria now belongs to france; it was formerly one of the barbary states, in the north of africa, and many very useful plants and trees flourish there; oranges, melons, cucumbers, cabbages, lettuces, and artichokes, grow in great luxuriance. the sugar-cane is cultivated with success; and everywhere may be seen quantities of white roses, from which a sweet essence is extracted. the stems of the vines, which the people tend, are sometimes so thick, that a man can hardly put his arms round them; and the bunches of grapes are a foot and a-half long. only think of bunches of grapes half a yard long! they must be something like those which we read of in the bible, that were brought to joshua, to show him what a fertile country was the land of canaan. acacia and cork trees grow in the woods of algeria; the natives obtain gum from the acacia. there are many mines, but the algerines make no use of them. the people themselves are strong in body, and of a tawny complexion. tunis is another of the barbary states, and contains a great number of people,--moors, turks, arabs, jews, and christians, merchants and slaves. all these carry on a large trade in morocco leather, linens, gold-dust, oil, woollen cloth, lead, ostrich feathers, horses, and soap. there are the same variety of vegetable productions that there are in algeria. [illustration] the cape of good hope is in the south of africa; it produces fine fruits and flowers, grapes, lemons, oranges, and figs, but no nuts. the aloe and myrtle grow to a great size, and the almond and wild chestnut are very plentiful. there are scarcely any manufactures, but the farmers keep immense flocks of sheep, and herds of cattle; and there is a vast quantity of fine wool sent every year to england; and ships provisions, such as beef, pork, and butter, are supplied to the vessels sailing to india, australia, and many other parts of the world; their other chief export is cape wine. in some parts of this country are large herds of zebras, antelopes, and giraffes, which are usually preyed upon by lions, obliging the shepherds to watch their flocks, and the farmers to ride about with loaded guns. a strange mode, my little readers will think, of being shepherds. [illustration] there have been no scarcity of french contributions; rich silks, velvets, satins, linens, fruits, woods, herbs, statues, machinery, furniture, iron-work, glass, plate, and a heap more of industrial products; and such splendid carpets. in the "arabian nights' entertainments" we read about the palaces of fairies and genii, with the floors covered with the richest carpets, and divans and cushions or gorgeous tapestry, and we long to see these carpets in reality; and so we shall at the exhibition, for there are some so magnificent, that i do not think the princess badroulboudour, or the fairy queen pari banou, ever sat on finer. and charming little models of ships; and such beautiful fans. do you know how many persons it takes to make a fan? fifteen; and although those fans at the exhibition are each worth several guineas, yet, in france, tens of thousands are sold at not more than a halfpenny a-piece. the french fan-makers get two shillings and six-pence a-day each, for their labour. the people of france are our next-door neighbours, almost; and from being our bitterest enemies they have now become our most intimate friends, and exchange visits constantly with us; steam vessels and railways having made the journey one of only a few hours. paris is the capital of france, and it is the gayest city in the world; there are theatres, balls, processions, feast-days, fairs, and more amusements than i can remember. but there are also numbers of very poor people, who almost live in the streets, and get food and clothing as they best can. some, who are called cheffoniers, go about with a fork and a basket, to pick up pieces of iron, rags, bones, or any stray valuables, if they can find them, from holes and corners in the streets, and from the dust heaps; others look for the ends of cigars, and sell them to be made into pieces of tobacco for the common people; and a number, i am very sorry to say, either beg or steal. among the peasantry there is a great deal of industry displayed. as they are all desirous of having a cottage and some land of their own, lads of fifteen or sixteen years of age, hire themselves as labourers to the farmers, and receive wages, out of which, and their mode of living, they save enough money in a few years, to buy a piece of land. if the land is fit for it, they plant it with vines; for the vineyards of france yield an abundant harvest, and well repay the labour bestowed on them. the french wines are among the finest and most expensive in the world. [illustration] the cottages of the peasantry are not remarkable for comfort, being very rude buildings, frequently having merely a hole in the roof for a chimney. they are mostly, however, extremely picturesque, completely covered with vines. the wines, called bourdeaux, burgundy, and champagne come from france. from the fruit of the olive-trees, which grow in vast quantities, a fine clear oil is obtained, and this forms a large part of the commerce of the country. the rearing of poultry is carried on to a great extent; and most of the eggs sold in london, which are used by us at breakfast, for sauces, and for puddings, come from france. most of the cottagers keep one or two small hardy cows, which their boys or girls, or old people, are usually leading about by a halter, to eat the rank grass in paths or road-ways between the fields. their milk and butter form a good part of the people's food. in tours and lyons, there are numerous manufactories for the most superb silks and damasks; some years ago, there were fifteen hundred pairs of silk stockings finished each day at lyons. the plate-glass of paris is now much better than that of venice, which was formerly the finest in the world, the plates being of an immense size and extraordinary clearness. their tapestry is beautiful; the tapestry of the gobelin in particular, for it is just like splendid painting. indeed, some of the designs, copied from pictures, surpass the originals, in point of beauty and brilliancy. there are many specimens of this tapestry at the exhibition, both in draperies, and fitted to pieces of furniture. the porcelain made at sevres is exquisitely beautiful, and is used for numerous ornamental purposes; vases, tea services, chimney ornaments, figures, and other articles. the painted papers, which represent various ornaments in painting, sculpture, and architecture, serve to employ a great number of people. watches, cutlery, shoes, dresses, bonnets, and jewellery, are also a good source of employment among numerous families. all these beautiful things we shall see at the exhibition. the forests, in france, are very extensive; and as wood is the general fuel used, great attention is paid to the growth of the trees. cattle and domestic animals are rather scarce, and the sheep are ill-managed; in winter, they are fed on straw and hay, instead of green food, so that the french meat is not so good as the english; but they have a nice way of dressing it. the country people are very simple in their habits and manners, and very frugal in their way of living; they live for the most part on black bread, garlic, fruit, and milk. the costumes of some of the peasants are exceedingly pretty. [illustration] what a many thousand contributions have come from foreign countries, yet even a greater number have been sent in from all parts of our own dear islands, england, ireland, and scotland. here is a silver tea-kettle, manufactured from a fourpenny-piece, by a working man. i think that would grace the diminitive tea-table of the emperor of the lilliputians. and a pair of boat-sculls, made of white ash, and only the size of writing-pens, which i dare say, the oars of the king of blefuscan's barge resembled; these, with a magnificent oar, thirty-six feet long, are intended as presents for his royal highness the prince of wales. here is a scarf, containing twelve miles and a-half of thread, three millions four hundred and seventy-five stitches, is nine feet ten inches long, three feet wide, and weighs only five ounces and a-quarter;--that came from ireland. look, too, at that beautifully embroidered dress; it came from ireland, and is worth seventy-five guineas. there are many little models of different buildings; and there is a colossal horse and dog; and two gigantic statues; and there is a nicely carved oak chair, made by an english ship-carpenter; and here are cotton stockings, manufactured so fine, that they look exactly like silk. there are also models of carriages, ships and machinery; a magnificient epergne of glass, with some large pearls, from ireland. a beautiful piece of sculpture, representing the scottish games, is the most remarkable contribution which has come from scotland. the english people are celebrated for their industry and perseverence; they manufacture numerous things, and carry on a alrge commerce with other countries. the industry of the peasants have made the soil produce wheat, barley, rye, oats, beans, potatoes, turnips, hops, hemp and flax. nearly every variety, of vegetables, and a great number of fruits, are also grown. there is abundance of timber, which is used for many purposes; the oak tree is chiefly employed for building ships. the ships of war are called the "wooden walls of england." the domestic animals are taken great care of; sheep and hogs, when killed, are made into mutton, pork, bacon, and ham. the english cheese and butter is superior to any other. there are abundance of mineral treasures found in various parts of the kingdom; indeed, the english people are greatly indebted to the well-worked mines for their wealth. at the exhibition, are several specimens of ores. in addition to the rich mines, and the vegetable productions, the english are celebrated for their superior manufactures, which fame they are enabled to enjoy by means of the most ingenious machinery, rail roads, and canals, by which they can easily and rapidly send their goods, and travel from one part of the country to another. cottons, woollens, linens, silks, iron, jewellery, leather, glass, earthenware, paper, and hats, are manufactured in great quantities. i dare say you would be much amused by a visit to manchester, in lancashire, where the art of spinning cotton is carried to a high perfection. there are more than a hundred and forty cotton factories in that city, where men, women, and children, are continually at work, minding the machines, which are about twenty thousand in number. when you first go into one of these factories, you hear a terrible noise of whirling and whizzing, and see an immense number of wheels flying round and round. halifax and leeds, in yorkshire, are the chief places for woollen cloth, the manufacture of which employs the greater part of the inhabitants. a weekly market is held in halifax for the sale of woollens, in a spacious building called the piece hall; but in leeds, the markets are held two days in the week, in the two cloth halls. staffordshire is famous for earthenware; the reason of this is, that there is such an enormous quantity of yellow clay suitable for that manufacture, found there. indeed, there are several towns and villages formed into a district called "the potteries;" and in consequence of the innumerable furnaces, which are always blazing, the place looks at night as if was on fire. gloves, lace, and stockings, are mostly made in nottingham, where there are several thousand machines for the manufacture of these things. from kidderminster, in worcester, we have very fine carpets; from gloucester, we have cheese and pins; northampton is celebrated for leather; shrewsbury, for flannel. the great mines are in cumberland, cornwall, northumberland, durham, and derbyshire. however, if i were to tell you of all the places in england, that are famed for different manufactures, i am afraid i should both exceed our space, and wear out your patience, which i should be sorry to do. so i will now tell you something about london. [illustration] london, which you know is the capital of our own dear native land, is the greatest commercial city in the world; it has been reckoned that the value of the property shipped and unshipped on the river thames, every year, is more than one hundred million pounds. an enormous quantity of property is laid in the london docks, at wapping; indeed, the warehouse for tobacco alone covers a space of nearly five acres, while the vaults underneath the ground are more than eighteen acres in extent. more coaches, omnibusses, waggons, vans, and other conveyances, crowd the streets of london than any other city in the world. you will, perhaps, be a little surprised when i tell you that in one principal street, seven thousand vehicles pass to and fro every day. almost every kind of manufacture is carried on in london; silk goods, jewellery, clocks, watches, ear-rings, hats, furniture, instruments of every kind, porter and ale, with many more that i cannot now remember. however, you must not think, from all this, there are no poor people in london; for, unfortunately, there are thousands. some beg, others steal, and those who are honest and able to labour, work. but those who cannot obtain work are very badly off; and persons die from starvation. the industrial manufactures of scotland are like those of england; the exports are linens, muslins, woollen stuffs, cottons, iron, lead, glass, earthenware, leather, and other articles. the chief manufacture is linen: but manufactures of stoves, and grates, and many other things, from their immense iron works, particularly from those of carron, are also a principal part of the industrial products. [illustration] the scotch people are remarkable for their thrift and prudence; the lower orders are in general well-educated, and it is the height of ambition in a scottish mechanic, to appear with his family in neat, clean dresses, on sundays and other holidays. the costume of the highlanders is very picturesque; the plaid is made of woollen stuff, of various colours, with a jacket, and a short petticoat called a kilt, which leaves the knees bare; the stockings are also a plaid, generally red and white, and do not reach up to the knees, but are tied round the legs with scarlet garters. the head-dress is a flat blue bonnet, as it is called, ornamented round with scarlet and white plaid, and frequently adorned with eagle's feathers. the highland women go without shoes or stockings, and wear short petticoats, a plaid jacket, and a plaid scarf. most of the scotch people are intelligent, and so far advanced in education, that even the miners in the south have a library, where they read, and improve their minds; and yet these poor miners were little better than in a state of slavery two hundred years since. the favourite musical instrument, with the scotch, is the bag-pipe; which does not, however, sound quite so well to our english ears, as it does to theirs. their national dances are the highland reel, and fling, which they perform with great agility and grace. the sheep and cattle are rather small, but give exceedingly good meat; and the sheep, in particular, are valued for their fleece, which is almost as fine as the best spanish wool. edinburgh, the capital of scotland, is, in the new parts of it, a fine clean city; the houses in the old town are excessively high, and the streets inconvenient; but the streets of the new town are very broad, and almost all in straight lines; some of them are a mile long. most of the houses are built of white stone, which sparkles as if it was inlaid with diamonds when the sun shines on it. the manufactures carried on in the city, are mostly cabinet-work, furniture, carriages, musical instruments, linens, shawls, silks, glass, marble, brass, and iron work. there are also many breweries, for edinburgh has long been celebrated for its ale, large quantities of which are sent to london, and other parts of the kingdom, glasgow, which is the principal manufacturing and trading town, contains extensive cotton factories. in many parts of the highlands, the natives are employed in feeding sheep and cattle, for the markets; and in the valleys, and other sheltered places, hemp, barley, flax, and potatoes, are cultivated, though unfortunately most of the barley is made into whiskey. in the more northernly parts the general employment is fishing. [illustration] ireland is a much warmer and more fertile island; it is celebrated, in point of industry, for its wool, butter, beef, hides, tallow, cows, horses, pigs, sheep, potatoes, wheat, barley, oats, and linen. linen is the chief manufacture. there are numerous mines, from which are obtained gold, silver, iron, copper, and lead; all very useful metals, i think. there are also quarries of marble, slate, and freestone; and in various parts are found coal and turf. in ireland, turf is the principal fuel used. the brewing of stout, and a strong bittered beer, for exportation; and the distilling of whiskey, another strong but spirituous drink, are other branches of irish industry. fishing is an important occupation with those peasants who live on the sea-shore, and near the rivers or lakes. the making of roads, draining bogs, and improving the land, now employ thousands of poor labourers, who formerly used to be without any occupation. the irish dairies are well-managed and are generally extensive; many counties in the south part of the island are occupied almost entirely by dairy farms. as many as thirty or forty cows are kept on some of them, for butter is the chief produce, and this is sent into england, portugal, and the east and west indies. some of the nice butter you eat on your bread and rolls comes from ireland. sheep and cattle are fed in great quantities on large pieces of land devoted to the purpose the sheep are large, and have fine wool. the mud cabin of the irish peasant is the most miserable cottage you can imagine; the walls are formed of clay, which hardens in the sunshine, the roof is made of sticks and straw, and the floor is the mere damp earth. it has frequently neither door, nor chimney, and consists of only one room; the furniture is rarely more than a stump bedstead, two or three stools, an iron pot, to boil the potatoes in, and a table to eat them from. generally, there is a small piece of land attached to the dwelling, and in this potatoes are grown; the peasants of ireland hardly ever eat anything besides potatoes. when they have enough of them to eat, and a little whiskey to drink, the poor people are exceedingly jovial and merry; they laugh, sing, and joke; and go to weddings, fairs, dances, and what are called in ireland "wakes," which, among the poor, is a kind of laying in state before funerals;--but sometimes the crops of potatoes fail, and then the unfortunate peasants die by hundreds from hunger. the favourite dance of the common people is called a jig. dublin, which, i dare say, you know is the capital of ireland, is an elegant city, with fine houses and good streets. the churches, the castle, the linen hall, exchange, bank, custom-house, and post-office, are all very noble buildings. there are also parks, gardens, theatres, canals, and other ornamental places throughout the city. from dublin have been sent models of carriages, specimens of metals, slates, and linens, and a model of a house made in granite. [illustration] i have now told you, my dear little friends, a great many stories about the industry of all nations, and we have gone through the world's show together. we have seen nearly all the useful and splendid things sent to the great exhibition from all parts of the world. i have told you about europe, and asia, africa, and america; and i must soon leave you. but before i go, we must have another look at the exhibition, and one more glance at those few things which we have not as yet seen. we forgot to examine this magnificent chess-board, worth one thousand two hundred guineas. you will doubtless wonder why it is such a dear board, but your surprise will cease when you observe that the "checks," as they are called, are of mother-of-pearl and tortoiseshell, while the rim is of beautifully burnished gold, and the chessmen are of gold and silver, elaborately wrought, and ornamented with the portraits of celebrated historical characters; one of them represents the emperor, charles the fifth. i dare say you would like to play a game with me on this chess-board. as a companion to this beautiful chess-board, is a very elegant colour box, fit for the queen, or the most noble young lady in the land, to use for painting with. and here is a model of the town of liverpool, with several thousand little people in the streets; and these figures are so exceedingly small, that a thousand of them would fit into an ordinary sized pill box. in contrast to this specimen of a great town in a minute space, we have in front of the transept a wonderful clock, which is kept in motion by a set of powerful electro magnets, eight in number, on which is wound a length of twenty-five thousand feet of copper wire. this gigantic time-keeper sets in motion the immense hands on the principal dial, which is twenty-four feet in diameter, besides two smaller ones which are fixed in front of the galleries, at the east and west ends of the building. i am afraid that it would tire you, were i to attempt to tell you exactly what electricity is, and must therefore satisfy your curiosity, for the present, by letting you know that it is caused by the coming in contact of different substances possessing peculiar properties, which cause them to vibrate, when they touch. there is another very curious clock in the exhibition, which will go for a hundred years before requiring to be wound up again; and there is one wheel in it which is said would take ten thousand years to go round once. next there is a case of stuffed birds, which came from scotland, and which we cannot help admiring. there are in this case specimens of all the various kinds of birds which are peculiar to scotland, neatly and carefully stuffed; and really they almost look as if they were alive. ah, ah! mister eagle, you are not so much to be feared now, i think, as you were when you lived in your lofty home in the highland mountains. and here is another case in which are all the different sorts of mother-of-pearl buttons that can be imagined; there is every variety of ornament on the buttons, which look exceedingly brilliant. this immense block of granite, from scotland, is not quite so pretty, though it is, perhaps, more useful; it is twenty feet long, and is a piece of the finest kind and colour that could be found. another very useful thing, also from scotland, is a large lighthouse bell, managed so as to ring very loud, to warn any ship that is going too near a dangerous rock or shoal, near the lighthouse where the bell may be. among the more beautiful specimens of industry, there are several elegant vases made of silver, and of a delicate material called parian, which is an imitation of parian marble; some of them are ornamented with blue and gold, and others are ornamented with silver. there is also a splendid tea-service, adorned with charming pictures of the dear old fables we all know so well,--the "lion and the mouse," the "wolf and the lamb," the "dog and the shadow," and others. near the very middle of the building, close by the crystal fountain, there are the splendid iron gates from coalbrookdale, which look very magnificent. i fancy samson would find it rather a difficult matter trying to bear off _these_ gates on his back, strong as he was. close by these gates there is a gigantic statue of our good queen, on horseback, which towers high over our heads; and she sits smiling at us as if she could see us looking so delighted. there are several gigantic things at the exhibition. here, for one, is a monster cake, covered with the most superb ornaments; it is four feet high, and weighs about two-hundred and twenty-five pounds. yonder is another monster contribution, an immense map of the busy city of manchester; and there is a huge railway carriage; and still further on, there is an iron wire, one mile long. at a little distance stands a magnificent bed and bedstead, fit for the queen to sleep in. it came from edinburgh, and is made mostly of materials which can be produced in scotland. and in this direction, we can see a set of beautiful mantelpieces and fenders, from sheffield, all decorated in the most elegant manner. the first mantelpiece we must look at is made of cast-iron; the mouldings of the cornice are richly ornamented, and supported by little pillars covered with graceful wreaths of oak-leaves, while the freize is adorned with a cluster of rich fruit. the next mantelpiece is painted white and gold, and has a burnished steel grate; while the third is painted blue and gold, and has a stove made on a new plan, for it is managed so that its own brightness shall help to throw out the heat of the fire in an equal and agreeable manner. the fourth and last mantelpiece is painted black, and ornamented with ormolu; it contains a polished steel stove. three ormolu fenders, and five bright ones are placed together with the mantelpieces; and they certainly make a goodly show. but we must now leave them, and go on to see some other wonders. here are several most beautiful loo-tables inlaid, and they seem to attract a good deal of attention from more than us. you look a little puzzled at the word _inlaid_; i think i must explain it to you, by telling you that it means pieces of different material let into a piece of furniture to ornament it. there are numerous models of various buildings in the crystal palace; those of york cathedral, and chance's lighthouse, are particularly well made. there is also a model of the britannia tubular bridge; and there are models of many of the fine public works of london. here is a pair of scissors made in sheffield, and ornamented in the most beautiful way, with a crown for a handle; and yonder are a pair of cotton stockings from ireland, spun so fine that they look exactly like silk, and indeed you would be likely to mistake them for silk, if you were not told they were merely cotton. how brilliant this collection of gems looks; how the stones sparkle! they have been sent as specimens of the jewels which ireland produces. but here are some pretty english agates; and a huge mass of irish rock crystal, which is very bright and clear. in a compartment, at a little distance, we may see a book, bound according to a new method, by which the leaves are so firmly placed together, that they would not loosen in ten years' time, no matter how the book was tossed about, unless they were purposely taken out. we must now have a look at the machinery department. firstly, there is the great steam-engine that works all the other steam-engines in the exhibition, though, of course, you cannot understand it by looking at it; neither can i, although i know so much more than you do. near it is a model of a new agricultural machine for cutting, turning up, and making into light mould, the clay of fields, so as to make it ready to receive the seeds to be set, without the farmers being obliged to plough the earth. there is a machine for making bricks and tiles, so that people may, if they like, form those materials for building houses cheaper and better than in the usual way. but here is a useful machine. it is a measuring machine, by which you could measure to the smallest size, even to the hundred-thousandth part of an inch! here is a very pretty contribution; it is a model of the house of the great play-writer, shakspeare,--of whom, perhaps, you may have heard,--and it is surrounded by figures representing different beautiful scenes from shakspeare's plays. it was made by a workman in his leisure time: and it certainly does him credit. it is called the shakspeare jubilee. yonder is another piece of ingenious industry; it is a group of figures showing all the various scotch games; there is one figure dancing the highland fling, another throwing the beam, and all the others engaged in similar sports. that came from scotland, of course. let us now go on to look at that splendid design embroidered in gold, and intended for a communion cloth. oh! here it is; does it not look beautiful? but here are several lovely specimens of china, and earthenware, which would grace the sideboards of the richest house in the land, i think. here is a fine marble font, made of devonshire marble, which is very nicely carved, as well as i can judge. further on, we have some less showy, but more solidly useful articles. various kinds of iron, copper, zinc, lead, silver, and gold ores are displayed, with oils, quartz, stones, coal, &c. there are lanterns on a new plan, microscopes, barometers, optical and philosophical instruments, farming implements, machines for melting metals;--besides hundreds of other articles which we cannot stop to notice more particularly. there are two or three very interesting models of mines, with mining machinery, and plans for improving the air of the mines, so as to make the poor miners more comfortable. and there are other models of ships, printing presses, looms, and machines for making gas, which deserve some degree of attention. there is also a new machine for printing cotton on both sides, which will be very useful, as the cotton printed with it will be as ornamental on one side as the other. there are four splendid and very powerful organs, and several beautiful piano fortes, in the exhibition; and there is an accurate model of plymouth breakwater, with a very very little ship attached to it, and all complete, even to the smallest rope ladder. plymouth breakwater is a vast heap of stones built across the entrance of the sound, so as to leave a passage for ships at each end, but preventing the heavy waves of the atlantic ocean from dashing into the harbour. it has cost more than a million of pounds in money. here we have a beautiful writing table for ladies, which is one of the most splendid things in the exhibition, and which came from that land of ingenuity and industry, switzerland. it is made of two kinds of wood, white and red, the swiss national colours; and is cleverly managed by machinery, so that by merely pressing a spring, the whole contents of the desk is laid before the spectator, while, at the same time, a stand for writing on, and a seat, are produced. it is covered with figures of men and animals, and with ornaments most exquisitely carved; and it is a writing table which the greatest lady in england might use. along the centre of the aisle, or chief walk, are arranged colossal statues, pillars of marble, beautiful fountains, magnificent feathers, crystals of alum, crystals of spermaceti oil, specimens of silk manufactures, from spitalfields; and fine cutlery, from sheffield. there is also an immense dome of iron and glass, forty feet high which looks very astonishing; and a curious russian chain bridge, which is very ingeniously made. besides these, we have a gigantic telescope, which attracts a great deal of attention from the crowd of people who are walking down the aisle. in the nave there are several beautiful pieces of sculpture. one is a colossal group, representing st. michael conquering satan; another is a figure of the celebrated warrior, godfrey of bouillon, mounted on horseback; and a third, is an amazon, who is just about to hurl her javelin at a ferocious tiger, who has fastened on the neck and shoulders of her frightened horse. here is also a figure of mazeppa on the wild horse, which is extremely well made, and, perhaps, reminds those of my little friends who have seen the play of "mazeppa" at astley's amphitheatre, of the scenes where poor mazeppa was carried along on the terrible horse's back, through brambles, thorns, and crashing boughs. but what have we here? a grim-looking growling bronze lion, from bavaria, who glares at us as if he would be only too glad to eat us up if he were alive, and does not seem at all the kind of beast one would like to shake hands, or rather paws, with. we have a charming representation of reinecke fox's adventures, by means of stuffed animals, in the german portion of the exhibition. the expression of the different animals is very funny, and makes us laugh to almost an inconvenient degree. the first group represents the fox, with his rosary in his hand, confessing his sins to the cock, who is listening very gravely, and reading him a sermon on his wickedness. the next group shows the tom-cat, coming to summon master reinecke to court, to answer the accusations brought against him; the fox sets out, and on his way wounds a poor hare, whom he carries with him. but we cannot stay to notice all the groups now; only we must just glance at the fox lying on the sheep's skin, after his repast, for here master reinecke's expression shows him to be so well satisfied and comfortable that it is very droll. in the russian division we may observe a most magnificent pair of candlesticks of bronze, gilt, which look exceedingly sparkling and brilliant, and are the first objects that meet our eyes as we enter the department. in the transept, at the opposite end to where the gates from coalbrookdale are situated, are another beautiful specimen of ornamented gates for a park, in the style of the elegantly wrought iron work, made about a hundred and fifty years since, and which adorn the entrances to many of the old mansions of england. some parts of these are tastefully gilt, and produce a remarkably pretty effect. it would take us more than a month to see everything in the crystal palace, and those who wish to examine all the wonders, must pay several visits. but we have, i think, seen enough for the present, and will now leave the exhibition, if you are satisfied. perhaps, before i go, you would like me to describe the ceremony of the opening of our palace of wonders, by our good queen? if so, i shall be very happy indeed to oblige you, by telling you all i saw on the first of may. early in the morning of that day,--soon after dawn,--thousands of people in london were wending their way towards hyde park; horses feet, and carriage-wheels clattered through the streets, and strange looking foreigners passed along among the crowd, all eager to see the procession. i dare say you would have been delighted with the grand sight:--first there came a long line of splendid carriages, containing various lords and ladies, in gorgeous costumes;--diamonds flashing, and feathers waving; next came a troop of life guards in scarlet coats, bright cuirasses, and glittering helmets: they were escorting the queen's carriage, which was followed by a goodly number of other carriages. you should have heard how the crowds huzzaed and shouted when they saw the queen, who looked very much pleased, bowing and smiling to her people. she entered the building amid the loud cheers and hurras, followed by prince albert, the prince of wales, and the princess royal. after staying a short time in the elegant robing-room, which was fitted up in a single night, her majesty proceeded to her throne, between flower stands, and tropical plants, past the coalbrookdale gates, and the fountains and statues with which the centre of the palace is adorned. when she appeared, the twenty-five thousand people, who were present, rose to welcome her.--ladies waving their handkerchiefs, the gentlemen their hats;--and you may readily guess how splendid the scene looked. even the sun popped out his head from the clouds, and poured a flood of golden light in through the glittering dome of the transept, to illuminate the brilliant spectacle. as soon as her majesty was seated on her throne, one of the organs commenced pealing forth the notes of the national anthem, the choir, which was collected for the occasion, singing to the music. after this, prince albert joined those gentlemen who have directed the affairs of the great exhibition, and going near to the queen, read to her an account of the exhibition from the commencement; to which her majesty answered, when the prince had finished, that she was much pleased with the description of the proceedings, and that she hoped the world's fair would do good to all mankind, by encouraging the arts of peace and industry, strengthening the bonds of love between all the nations of the earth, and promoting a friendly rivalry among our fellow creatures, in the useful exercise of those faculties which have been given by god for the good and happiness of all mankind. the queen having read this answer, the archbishop of canterbury approached the throne, and offered up a prayer to heaven, intreating the lord's blessing on the exhibition; that it might benefit every body on earth, making them love and help each other. i hope all that heard the prayer, joined in it with heart and soul: and i hope, too, that my dear little readers will think of it when they go to the crystal palace. at the close of the prayer, the choir sang the hallelujah chorus, and you may form some idea of the effect of this performance, when i tell you that all the persons who sing at the queen's chapel, at st. paul's cathedral, westminster abbey, and st. george's chapel, windsor, were all singing together, besides part of the band of the sacred harmonic society, pupils of the royal academy of music, and many other songsters, both foreign and english. the immensity of the building left scope for the rich volume of sound poured forth; and you may imagine what an effect the splendid strains had on the feelings of the multitude of spectators. indeed, one of the audience,--a chinaman, was so excited by the grandeur of the scene, and the triumphant music, that he rushed forwards, made his way through the crowd of nobles and ladies that surrounded the queen, and, advancing close to her majesty, saluted her by a grand salaam, which she graciously acknowledged with a smile and a bow. a salaam, you must know, is the eastern way of bowing, and consists in bending the head until it almost touches the ground. when the hallelujah chorus ceased, the procession was formed for the queen to go round the building. first went the heralds, in their splendid costumes; then a great number of gentlemen, who were more immediately concerned with the exhibition; after them, the duke of wellington,--of whom, i dare say you know,--with more gentlemen, and the archbishop of canterbury; and then the queen and prince albert, with the prince of wales, and the princess royal, both of whom looked extremely delighted and astonished with the gorgeous spectacle they were viewing. the royal family was followed by a number of lords, ladies, and attendants, the procession being concluded by heralds. the train first went to the west end of the nave, on the north side, everybody cheering loudly as it passed. the view varied every minute, but was always picturesque, and beautiful. even those persons who were most acquainted with the wondrous objects that lay on every side, were surprised by the new and charming attractions displayed. the indian collection, and the compartment filled with specimens from the colonies, were left behind; the department devoted to sculpture, and other finer products of industry, was passed, and the procession moved into that portion of the palace which contains the english manufacturing products. you might then have caught a glimpse, over the heads of the spectators, of the furniture court, where the furniture is placed; and of the fixed machinery beyond it, the massive iron form of each machine looking as much as to say "move me, if you can." then the procession passed the enormous dome of iron and glass, the two gigantic statues, the figure of shakspeare, and the many other objects which adorn the centre aisle; leaving behind the furs of bears, and other wild animals, hung beneath the galleries, and the carpets which lent their brilliant colours to finish the decorations; it reached the western entrance, where it was reflected in the immense mirror, exhibited at that point. then, turning round by the model of the liverpool docks, it was returning on the south side of the nave, when the gigantic organ placed there, suddenly hurled forth an immense volume of music, which sounded extremely fine: but every one was already so much astonished, that i do not think anything more could surprise them. at length the procession reached the transept, round the south end of which it proceeded, and then swept into the foreign department of the exhibition, where great efforts had been made to receive it properly. the french had collected together all the choicest specimens of their manufactures to grace the foremost part of their division; and i am sure you would have admired the tasteful manner in which the contributors decorated the collection. some of the other countries, as their exhibitors had sent in their contributions sooner than the french, were of course able to make a more satisfactory appearance. the two organs, from france and germany, each, in turn, poured forth their music as the procession passed; and two or three of the queen's bands played a march as the pageat moved round the eastern end of the building. at last the procession returned along the north side of the nave, the cheering and waving of hats and handkerchiefs, which had continued all the time getting now more joyful than ever; and the queen returned once more to her throne. one of the noblemen, named the marquis of breadalbane, then called out in a loud tone of voice, that her majesty declared the exhibition open; a flourish of trumpets, and a roar of cannon, told the people outside that all was now concluded, and the queen, with the royal family and other attendants, left the crystal palace, the choir again singing the national anthem. in order that the workmen and their families, who come to see the exhibition, should live comfortably when they return home again, prince albert has had a model building erected, with four dwellings, or sets of rooms, each containing all the conveniences essential to a distinct family-house, with four distinct entrances for the four different families, such as he wishes every honest working couple in this country, and indeed every honest couple in all parts of the world, should possess. and, in order to shew to working men, and to builders, and to persons of property who desire to do good, how they can usefully assist their fellow creatures to comfortable habitations, for the same rent that they now pay for closely-built, unhealthy ones, he has erected these four model houses under one roof, each of them dry, warm, convenient, fire-proof, and healthy, and yet cheap. they are built of very hard hollow bricks, made by machinery, and are situate at the corner of the barrack yard, near to the crystal palace, and will be shown freely to all persons visiting the world's fair. now, boys and girls, good-bye; i know you are sorry to see me going away, and you may be certain i am sorry to be obliged to leave you. but i hope we shall soon meet again, for i am thinking of coming to see you very shortly, to tell you more stories and have another talk with you. so, if you say you have been amused, and have learned something, by reading these stories, i will pay you another visit soon, and tell you something more about other things. but in the mean time, let us hope that the suggestions of prince albert, the husband of our gracious queen, will do good; and that every body, and every nation, may become better, and learn more, and love each other more, in consequence of meeting together, in friendship and harmony, at "the world's fair." [illustration] * * * * * juvenile works published by thomas dean and son, threadneedle-street. the first history of england that should be placed in the hands of a child. by miss corner, author of the play grammar, every child's history of england, scripture parables, &c. containing, an interesting description of the ancient britons, and their civilization by the romans; the conquest of the romans and britons by the saxons; the life and times of alfred the great; the norman conquest; the feudal times; the manners and condition of the people of england in the middle ages; in the sixteenth, seventeenth, eighteenth, and nineteenth centuries, to the present time. printed in large type; with twenty-five pages of illustrations. s. d. bound, suitable for a present, in blue cloth, gilt edges; or, in eight parts, d. each, stitched in fancy wrappers. every child's history of england: with a map, and questions to each chapter. particularly suited for children, and for home, or infant school reading. by miss corner, author of the play grammar,--scripture parables, &c. s. sewed; 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or, s. d. coloured. the four elements:--or, fire, air, earth, and water. illustrated for little folks. and the old english nursery rhyme of simple simon, set to music. on five large plates; and done up in a fancy cover. price s. plain: or, s. d. coloured. the five senses,--hearing, seeing, smelling, tasting, and feeling. and the four seasons,--spring, summer, autumn and winter. illustrated for little folks, on five large plates; and done up in a fancy cover. s. plain; or, s. d. coloured the nursery rhymes of old england, set to music, for little folks. containing, the queen of hearts,--bye! baby bunting,--who comes here? a grenadier!--little boy blue,--and, the lion and the unicorn. illustrated on five large plates; and done up in fancy cover. price s. plain; or, s. d. coloured. the royal nursery picture book,--the nursery alphabet,--the royal family,--the comparative sizes of animals,--and a "morland." s. plain; or, s. d. coloured. pleasant tales for little people. an interesting collection of amusing and instructive stories, for young persons. with upwards of eighty superior engravings, s. d. bound in fancy green cloth, with gilt edges and side. visit to the zoological gardens, regent's park. a pleasing description of this delightful place of fashionable resort, and of the nature and peculiar habits of the many rare and remarkable animals contained therein. by j. bishop. square size, with coloured engravings, and cuts of the animals. s. bound in cloth. a gift to young friends; or, the guide to good; about the good man of the mill,--from whom all good things come--the lost purse,--self-will,--the careless boy,--the good boy,--and the way to save. in words of one syllable. by miss corner. square size, with seven coloured engravings.-- s, in cloth. short tales in short words, about the lame boy,--the sea shore,--the cross boy,--and the stray child. by mrs. burden. square size, with seven coloured engravings.-- s. in cloth. little child's alphabet of nouns, or book of objects: the letters in large and small characters; each letter illustrated by a number of pleasing engravings of objects expressive of the letter.-- in large to., with the engravings neatly coloured. geographical alphabet; a new and pleasing introduction to a knowledge of some of the most celebrated places, or interesting countries, of the habitable world. by b. clayton. in large to., with twenty-six coloured engravings. peter pallette's pictures for painting: thirteen numbers, price d. each; or bound in vols, st series, s. d. nd series, s. d. worret's new outline drawing-book; a series of progressive lessons, by which the principles of the art, as applied to figure, ornamental, and mechanical drawing, may be easily and correctly acquired.--on stone, by w. heath. s. the set of six numbers; or s. d. in cloth. every child's drawing-book; easy and familiar subjects by heath and barfoot. in seven progressive numbers. s. the set. young artist's drawing-book of easy subjects, in lithography and ink. by barfoot and heath. in numbers. s. the set. =grandpapa easy's coloured= original and splendid pictorial toy books, six-pence each. size, large octavo super-royal. grandpapa easy's little pig's ramble from home. embellished with eight coloured engravings. grandpapa easy's laughable story about tom pepper. with twenty coloured engravings. grandpapa easy's two sisters; or, who would not be industrious? eight coloured engravings. grandpapa easy's 'little gentleman,'--general tom thumb. with eight coloured engravings. grandpapa easy's new mother goose and the golden eggs. eight coloured engravings. grandpapa easy's lady golightly and her cousins the grasshoppers. with nine coloured engravings. grandpapa easy's new story of the lion and the unicorn fighting for the crown. eight coloured engravings. grandpapa easy's pretty poetry, about trees, fruits, and flowers. with twenty-seven coloured engravings. grandpapa easy's jacko's merry method of learning the pence table. eight coloured engravings. grandpapa easy's pretty poetical spelling book. twenty-eight coloured engravings. grandpapa easy's countries of europe. embellished with fourteen coloured engravings. grandpapa easy's marquis of carabas; or, new puss in boots. with fifteen coloured engravings. grandpapa easy's amusing addition; a new poetical number book. sixteen coloured engravings. grandpapa easy's cock robin alive and well again; with seven coloured engravings. _all six-pence each,--with handsome coloured engravings._ =grandmamma easy's coloured= original and splendid pictorial toy books, six-pence each.--size, large octavo super royal. grandmamma easy's new stories about the alphabet. with twenty-six coloured engravings. grandmamma easy's merry multiplication. with seventeen coloured engravings. grandmamma easy's new story about old daddy longlegs. illustrated with eight coloured engravings. grandmamma easy's new story about little jack horner. with eight coloured engravings. grandmamma easy's michaelmas day, or, fate of poor molly goosey. eight coloured engravings. grandmamma easy's alderman's feast: a new alphabet. illustrated with eight coloured engravings. grandmamma easy's account of the public buildings of london. with twelve coloured engravings. grandmamma easy's wonders of a toy-shop. embellished with eight coloured engravings. grandmamma easy's new story of the queen of hearts. with eight coloured engravings. grandmamma easy's new story about little tom thumb and his mother. eight coloured plates. grandmamma easy's pretty stories about the elephant. embellished with eight coloured engravings. grandmamma easy's pretty stories about the camel. with nine coloured engravings. grandmamma easy's travels of little matty macaroni. with nine coloured engravings. grandmamma easy's dame bantry and her cat; a humourous tale; with seven coloured engravings. _all six-pence each,--with handsome coloured engravings._ =new series of original pictorial toy books.= six-pence each, with splendid coloured engravings. entitled =cousin honeycomb's= amusing multiplication; illustrated and explained, in twenty appropriate engravings. amusing substraction; rendered easy and plain by twenty-three appropriate engravings. amusing division, made familiar to the opening mind, by twenty-three appropriate engravings. amusing pence table; in a new, easy, and pleasing manner; with fifteen appropriate engravings. railway alphabet, shewing all that can be seen in railway travelling, exhibited in twenty-four engravings. alphabet of trades; exhibiting the working of the several trades, in forty-one descriptive engravings. new royal a, b, c, and spelling-book, in a new and familiar manner: with twenty-six pretty engravings, and twenty-six large ornamental coloured letters. pleasing popular rhymes for the nursery, or, the sayings and singings of infancy, in a new dress; ornamented with twenty-six humourous engravings. pleasing popular nursery riddles, and puzzles; upon the same plan as the above; thirty engravings. my aunt's ball; an alphabet; shewing who were there,--what they had,--and how they behaved themselves,--with twenty-four engravings. a prince and his three gifts; how he used his three gifts; and about a good and beautiful lady; with eight large engravings. story of little joey, who came up to london a poor little boy, and afterwards became a great man;--with ten engravings. tales of the months and seasons: and what we see and enjoy all the year round; with twelve engravings. the mouse and her sons; a rural tale;--with eight coloured engravings. uncle buncle's original toy books, six-pence each. embellished with large appropriate colored engravings, and in fancy covers. uncle buncle's death and burial of poor cock robin, and the trial of the sparrow for shooting him. with seven coloured engravings. uncle buncle's new story about master nobody, and his many wonderful exploits. coloured engravings. uncle buncle's visit to little johnny green, the best little boy that ever was seen, with coloured engravings. uncle buncle's two little cottage children, and the means by which they became rich. seven coloured engravings. uncle buncle's alphabet of objects. embellished with many coloured plates. uncle buncle's new a, b, c. with fourteen pretty and appropriate coloured pictures. uncle buncle's new stories about animals. seven coloured engravings. uncle buncle's comical boys, with fourteen coloured plates. uncle buncle's new stories about birds, seven coloured pictures. uncle buncle's lord mayor's show; a new and popular multiplication table: with fourteen coloured pictures of the procession by land and water. uncle buncle's story about the sick little robin, and his kind little nurse jenny wren. with seven coloured engravings. uncle buncle's stories about little peter's visit to the farm. with seven coloured engravings. =corner's historical library,= for youth, schools, and families: published by dean & son, , threadneedle-street, london: comprising a complete history of every nation in europe, _uniformly printed, each country in a separate volume; with illustrations from historical subjects, elegantly engraven on steel, from designs by franklin, jones, and gilbert; and an accurate map to each volume; well bound in cloth, lettered_; commencing with the earliest period of authentic record, and brought down to the present time: accurately pourtraying the national characteristics, and domestic habits, of the people. by miss corner, _author of "questions on the history of europe," a sequel to mangnall's historical questions, &c. &c._ the object of these works,--peculiarly suited to schools and families,--is to furnish the reader with a faithful history of each nation, interspersing it with an accurate account of the religion, laws, customs, national characteristics, and domestic habits of the people, in the various periods of their history. in writing these elementary treatises, one especial object has been kept in view--that of adapting them to the capacities of young people and occasional readers: by this means, while they embrace information and entertainment for all, they attract the rising generation, by simplicity of language, and clearness of detail, and render comparatively easy the attainment of a knowledge of the leading events of history. the many high encomiums awarded to these works by the public press, and the very considerable acceptance they have met with in schools and families, are proofs that the efforts of the author to render historical knowledge pleasing, and easy of attainment, are not unappreciated by those to whom the care of the rising generation is entrusted. these series of histories, by miss corner, comprise the following: the history of england; a new edition; with chronological table; twentieth thousand; _s_. _d_. cloth, lettered; or bound up with questions on the history, _s_. illustrated with a map, and five historical engravings,-- . rowena presenting wine to vortigern. . king john signing magna charta. . henry vii. proclaimed at the battle of bosworth field. . oliver cromwell dissolving the long parliament. . coronation of queen victoria--the peers rendering homage. "it is important that history meant for young englishmen should be free from political poison, and this book will be found unexceptionable on this score."--_british banner_. "we have much pleasure in stating that this book is in another new edition, and its merits deserve it; it is well written, and admirably adapted for a school or reward book."--_academic and collegiate circular_. "miss corner's england and wales, we perceive, has just reached another new edition, in which the addition of the chronological table will be a great desideratum; the work is well written, and is equally adapted for a school, or, indeed, a gift book."--_bent's literary advertiser_. "we know no histories more likely to prove useful and agreeable in the instruction of children."--_britannia_. "the style of the book throughout renders it worthy of the support it has secured."--_gospel magazine_. "miss corner has chosen her epochs skilfully, and sketched them in a manner to make an adequate impression."--_literary gazette_. the history of ireland; new edition; seventh thousand; _s_. _d_. cloth, lettered; or bound up with questions on the history, _s_. illustrated with a map, and three historical engravings.-- . st. patrick preaching christianity to the king and nobles. . lord thomas fitzgerald renouncing his allegiance to henry viii. . entry of james ii. into dublin. "the history before us is well executed."--_literary gazette_. "miss corner's style of writing will produce habits of thinking."--_morning advertiser_. "the historical facts, always correct, are detailed in plain and concise language. this is one of the best class books on ireland, for young people."--_limerick standard_. the beauty of composition throughout the writings of miss corner is singular and fascinating.--_sun_. miss corner has acquired a deserved celebrity for the singularly-attractive and intelligible manner she has in narrating history.--_critic_. the history of scotland; new edition; ninth thousand; _s_. _d_. cloth, lettered; or bound up with questions on the history, _s_. illustrated with a map, and three historical engravings.-- . coronation of the infant king david ii. and his queen, at scone, . james v. taking refuge at sterling castle. . queen mary's escape to england. "we sincerely recommend this history as peculiarly suited to the meridian of schools."--_ayr observer._ "this meritorious work is written in a very easy and agreeeble style, perfectly adapted to the capacities of the young persons for whom it is intended."--_times_. "we have perused this history with much interest, delighted with the ease and perspicuity of style, and with the clearness and force of the narrative."--_chronicle_. "peculiarly adapted for instructive family reading."--_caledonian mercury_. the history of rome; from accepted english and foreign authorities, as macpherson's annals of commerce, keightley's roman history, smith's and adam's greek and roman antiquities; dr. arnold, niebuhr, &c. with questions to each chapter, a chronological table, and a map of the roman empire; _s_. _d_. bound in cloth, lettered. "miss corner's history of rome will assuredly ere long supersede all the roman histories at present used in schools, it is well written, and the historical facts elicited by the learned labours of niebuhr, arnold, &c, are made to take the place of the fabulous accounts which have hitherto passed current as authentic history; at the same time the popular early legends are not omitted, but their doubtful nature pointed out."--_westmister review_. "an excellent feature in this history is the continual effort to open out to the young reader the household life and social customs of the romans, for without this, ancient history can have no reality for children."--_educational times_. "its contents form a correct history of the roman empire, from its beginning."--_church of england journal_. the histories of spain and portugal; new edition, fifth thousand; _s_. _d_. cloth, lettered; or bound up with questions on the histories, _s_. illustrated with a map, and three historical engravings,-- . inez de castro entreating the king to save her life. . interview of columbus with queen isabella. . the cortez taking the oath of allegiance. "miss corner gives a clear and striking account of the different kingdoms that at various times were founded in spain."--_edinburgh review_. "so concise and plain as to be at once adapted to the capacities and volatility of young people, while they are useful compendiums for adults."--_times_. the history of france; tenth thousand, new edition, with continuation of events to the presidency of louis napoleon bonaparte; _s_. _d_. cloth, lettered; or bound up with questions on the history, _s_. illustrated with a map, and three historical engravings,-- . the coronation of charles vii. . a french tilt, or tournament. . bonaparte's expedition across the alps. "the writer has borne in mind throughout, that simplicity of style was essential to her purpose, and has selected those facts which are best adapted to give an idea of the events and the customs of the successive ages."--_baptist magazine_. "miss corner appears to be an excellent historian for the school room. she narrates with fluency and clearness, and in a concise and lively manner, the leading facts, so as to convey the spirit of history, and indicate the characteristics of the people and the country, as well as the rulers and famous characters."--_spectator_. "we look upon miss corner's work with great interest, as being peculiarly adapted to the minds of young people, and being free from that inversion of facts by which history is so often made subservient to party purposes."--_nonconformist_. the history of denmark, sweden, and norway; _s_. _d_. cloth, lettered; with a map, and two elegant historical engravings. . a norwegian family listening to the songs of their scalds, . submission of the order of nobles to frederick iii. "the two chief qualities of a good book are usefulness of subject and cleverness of handling, and these requisites miss corner's histories exhibit in an eminent degree. the frequent intermixtures of government between the three countries have indeed tended materially to embarrass this portion of european history, but miss corner by an accurate arrangement of dates, and a judicious connection of events, has set every thing in a clear light."--_post magazine_. the history of poland and russia; _s_. _d_. cloth, lettered; with a map, and three elegant historical engravings. . assassination of demetrius. . john cassimer, worn out by misfortune, resigning his crown to the diet. . flight of the inhabitants of moscow at the approach of the french army. "this volume forms one of a series of histories for the use of young persons; the present volume is, however, more descriptive than historical, which we consider an advantage; the living manners of the poles and russians being much more instructive and entertaining to young english readers."--_tait's magazine_. "miss corner has succeeded in compressing into a small compass all the leading events of history, without the slightest obscurity, or without sinking her book into a dry chronicle of facts."--_britannia_. the history of turkey and the ottoman empire; including greece, syria, and the holy land; _s_. _d_. cloth, lettered; with a map, and three elegant engravings. . selim ii., receiving the ambassadors of maximilian, emperor of germany. . mahomet expounding the koran at medina. . reschid pacha reading the hatti scheriff of to the ambassadors and great officers of state. "the narrative is so well arranged and so agreeably diversified by occasional remarks on individual and national character, as to render history attractive even to the very young; and the information is conveyed in a style remarkable for its unaffected simplicity and clearness."--_morning post_. "the leading features of turkish manners, laws, and policy, are accurately and forcibly pourtrayed, while the narrative is distinguished for simplicity, perspicuity, and completeness."--_conservative journal_. the history of italy and switzerland; _s_. _d_. cloth, lettered; with a map, and three elegant historical engravings. . pope martin v. riding through the streets of rome, the emperor and elector leading his horse. . massaniello haranguing the populace. . william tell and the other swiss patriots holding their nightly meetings. "brief, clear, and correct; well adapted for young persons."--_leamington spa chronicle_. "written with great care and ability."--_john bull_. "a very useful educational book."--_literary gazette_. the history of holland and belgium; _s_. _d_. cloth, lettered, with a map, and two elegant historical engravings. . assassination of william of orange. . admiral van tromp shot whilst animating his sailors. "the present, like the proceeding histories from the pen of this intelligent lady, is distinguished for its conciseness, elegance of expression, and clearness of detail."--_manchester times_. "a condensed mass of knowledge, well put together, and prettily illustrated."--_church and state gazette_. "to a pleasing, fluent, narrative style, miss corner unites a nice discrimination, and never suffers matters which sully the mind to appear in her pages."--_surplice_. "we cannot too strongly recommend these admirable histories, and we feel satisfied that no parent or preceptor can place better works in the hands of a youth."--_academic and collegiate circular_. "altogether we do not know of a more agreeable or instructive present for youth; and each history is illustrated with a map and engravings, which considering the price of the work, are of a superior description."--_times_. "the authoress shows much discrimination in conveying in language suited to her readers the results of the laborious investigations of other scholars."--_educational times_. an accurate history of greece. from accepted authorities, english and foreign; as crete's and chambers's histories of greece, smith's greek and roman antiquities, thirlwall and wordsworth's greece, smith's mythology and biography, annals of commerce, library of useful knowledge, &c. with questions to each chapter, a chronological table, index, and a coloured map of the greek states. price _s_. bound in cloth, lettered. we have not met with any history of greece that contains, within the same compass, so large an amount of interesting and valuable information. miss corner writes concisely, perspicuously, and sensibly.--_westley banner_. a concise history of greece, well adapted for schools.--_cambridge independent press_. this is a very excellent compendium of grecian history, and such are the merits of the work that we shall not be surprised at its becoming a popular educational book.--_the british mother's magazine_. remarkably clear in its arrangement, while the simple and easy style in which it is written, peculiarly fits it for popular use, it displays much careful research on the part of its author.--_englishwoman's magazine_. miss corner has the art of writing so as to be understood by youthful readers.--_london literary journal_. by far the best introductory school history of greece we have ever seen.--_british banner_. a combination of simplicity of narrative, with comprehensiveness of detail, admirably adapted for the use of the school-room.--_douglas jerrald's weekly news_. with feminine delicacy, miss corner omits what should be omitted, giving meanwhile a narrative of the broad character and features that mark the progress of a nation.--_express, evening paper_. the results of the best modern scholarship are here given.--_leader_. miss corner's histories require no recommendation of ours to bring them into notice. this volume, her history of greece, is written with great clearness and fluency, the fabulous tales which disfigure so many professedly authentic histories of the greeks are discarded. we cordially recommend this work for the school-room, or family circle.--_gospel herald_. religious works published by thomas dean and son, threadneedle-street. * * * * * dedicated (by permission) to the lord bishop of lincoln. the rev^d. edward bickersteth's christian psalmody; _(of which upwards of one hundred and fifty thousand have been used,)_ comprising a collection of above nine hundred psalms, hymns, and spiritual songs, selected and arranged for public, social, family, and private worship, by the rev. edward bickersteth, late rector of watton, herts. sold at s. in cloth,-- s. d. in embossed roan,--and s. d. in calf,-- copies, in cloth, £ ,-- for £ ,-- for £ s. or for £ s. a fine thin paper edition, s. d. in cloth, gilt edges;-- s. d. roan, gilt edges;--and s. d. morocco, gilt edges. an edition, in large type, is also published, at s. d. cloth; s. d. roan; and s. in calf. to meet the wants of poorer and village congregations, the church and village psalmody, has been prepared by the rev. edward bickersteth: consisting of three hundred and ninety of the above psalms and hymns most adapted to public worship; and so arranged as to be used at the same time with either of the larger editions of "christian psalmody." it is published for one shilling, done up in cloth binding:--or copies for £ ;-- copies for £ s. d.;-- copies for £ s. clergymen and congregations may also be supplied with an abridged or sunday-school edition; at d. in cloth;-- copies for s;-- copies for s;--or for s. d. and bound in red sheep, at d;-- copies for s. d;-- copies for s;--or copies for s. also, an improved edition of william hutchins callcott's arrangement of ancient and modern psalm and hymn tunes, for the organ and piano-forte, adapted to the above, and applicable to any other selection of psalms and hymns. in cloth, at s. d;--or, half morocco, s. d.-- copies in cloth for £ s.--and in half morocco for £ s. the life of christ, by the rev. t. timpson, illustrated by choice passages from one hundred and thirty-eight eminent british and foreign divines, and embellished with seventy engravings after the best masters. s. d. elegantly bound and embellished, and with gilt edges. tales of the reformation; an account of the progress of that important event; with some interesting tales of martin luther, and other eminent men who were involved in its early development. by a.m. sarjeant, author of tales of the early british christians, &c. s. d. cloth, with frontispiece. the bible and the people; a series of plates, exhibiting the inestimable benefits of the bible, and its great power as a means of effecting present and lasting good.--lithographed by robinson, and printed on plate paper, s. d. tinted;--or, coloured, s. d. hieroglyphical bible; a pleasing introduction to reading the holy scriptures, numerous words being depicted by engravings, to the number of two hundred and twenty. d. sewed. the believer's pocket companion: passages, (chiefly promises,) from the sacred writings; with appropriate observations, in prose and verse. by j. evans. d. sewed. =new scripural series of coloured sunday books=: six-pence each. _with coloured engravings, correctly representing the costumes of the people and the scenery of the countries in which the incidents described took place_. the life of our saviour. embellished with eight coloured engravings. two brothers; or, history of cain and abel. embellished with twelve coloured engravings. the history of isaac and rebekah. embellished with ten coloured engravings. the history of joseph and his brethren. embellished with nine coloured engravings. ruth and naomi; or, the affectionate daughter-in-law. with twelve coloured engravings. elisha, and the widow's cruise of oil. with fourteen coloured engravings. the disobedient prophet; or, what harm can there be in it? with eleven coloured engravings. the scripture historical alphabet. embellished with fifteen coloured engravings. the history of abraham. embellished with eight coloured engravings. esau and jacob; or, forget and forgive. embellished with eight coloured engravings. the life of moses. embellished with seven coloured engravings. the history of samuel; or, children may be wise. embellished with seven coloured engravings. the shepherd king; or, history of david. embellished with eight coloured engravings. the prophet daniel; or, the captives of judah. with eight coloured engravings. new series of scriptural prints, illustrative of the life of our saviour. _size, nine inches by fourteen, price, s. each, full coloured; or, d. tinted._ angels appearing to the shepherds. and the angel said unto them--fear not; for, behold, i bring you good tidings of great joy. luke, ii. . adoration of the magi. and when they saw the young child with mary his mother, they fell down, and worshipped him. matthew, ii. . christ disputing with the doctors. they found him in the temple, sitting in the midst of the doctors both hearing them, and asking them questions. luke, ii, . the baptism of christ. the heavens were opened unto him, and he saw the spirit of god descending like a dove, and lighting upon him, matt. iii. . christ blessing little children. suffer the little children to come unto me, and forbid them not; for of such is the kingdom of heaven. mark, x, . christ healing the blind. jesus said unto him, receive thy sight: thy faith hath saved thee. luke, xviii. . the raising of lazarus. he cried with a loud voice, lazarus, come forth. and he that was dead came forth, bound head and foot. john, xi. . the widow's mite. this poor widow hath cast more in, than all they which have cast into the treasury,--for she did cast in all that she had. mark, xii. . christ's entry into jerusalem. many spread their garments in the way; others cut down branches from the trees, and strewed them in the way. mark, xi. . the last supper. this do in remembrance of me. luke, xxii. . peter denying christ. and the lord turned, and looked upon peter, and peter remembered the words of the lord, before the cock crows, thou shalt deny me thrice. and he wept bitterly luke, xxii, . christ before pilate. pilate asked him, answerest thou nothing? behold how many things they witness against thee. mark, xv. . taking down from the cross. when joseph had taken the body, he wrapped it in a clean linen cloth, and laid it in his own new tomb. matthew, xxvii. . * * * * * amusing panoramas of animals,--with their uses and habits,--for children.--eight animals, with characteristic coloured engravings, in each book. sorts, d. each. peter palette's coloured scrap book; in six parts, each part comprising six leaves, and each leaf containing several interesting subjects.--six-pence each part;--or the set, bound together, s. d. the child's own scrap book of pictures, by peter palette. seven parts, coloured; to size. d. each; or the set, bound together, s. juvenile works. published by thomas dean and son, threadneedle-street. * * * * * the first history of england that should be placed in the hands of a child. by miss corner, author of the play grammar, every child's history of england, scripture parables, &c. containing, an interesting description of the ancient britons, and their civilization by the romans; the conquest of the romans and britons by the saxons; the life and times of alfred the great; the norman conquest; the feudal times; the manners and condition of the people of england in the middle ages; in the sixteenth, seventeenth, eighteenth, and nineteenth centuries, to the present time. printed in large type; with twenty-five pages of illustrations. s. d. bound, suitable for a present, in blue cloth, gilt edges; or, in eight parts, d. each, stitched in fancy wrappers. every child's history of england: with a map, and questions to each chapter. particularly suited for children, and for home, or infant school reading. by miss corner, author of the play grammar,--scripture parables, &c. s. sewed; or with the map coloured, s. d. in cloth. papa and mamma's easy lessons in geography; or, the elements of geography, in a new and attractive form. by anne maria sargeant, author of bible geography, &c. embellished with many illustrations: and intended as a companion to miss corner's play grammar. price s. stitched, or s. d. bound in cloth. guide to useful knowledge: by charles butler. containing, in the popular form of an easy and familiar catechism, the newest and most useful information connected with the arts, sciences, and the various phenomena of nature. for the use of schools and families. fourth edition, corrected. s. d. bound in cloth. guide to geography: by charles butler. a new, pleasing, and concise description of the five great divisions of the globe: the empires, kingdoms, and states, into which they are divided; and the natural, mineral, and vegetable productions of the several countries; with the numbers, and the manners and customs of their inhabitants. new edition, corrected, s. d. bound in cloth;--or, with seven glyphographic maps, and the use of the globes, s. bound. the play grammar; or, the elements of grammar explained in short and easy games. by miss corner. s. d. cloth lettered, with richly coloured frontispiece, and numerous engravings on wood; or, s. sewed in fancy covers, with plain frontispiece. christmas berries and daisy chains, for the young and good. a collection of pleasing and instructive tales in poetry and prose, adapted to the youthful mind. by the author of spring flowers and summer blossoms, &c. printed in large type; with eight pages of tinted illustrations. price s. d. bound in fancy cloth, gilt edges and sides, suitable for a present. silver blossoms to produce golden fruit: being golden keys to the good old proverbs, in interesting tales. by the author of spring flowers and summer blossoms, christmas berries, &c. with eight pages of tinted illustrations. price s. d. bound suitably for a present, in fancy cloth, with gilt edges and sides. stories of the elements: or, the old man and his four servants; volcanoes and earthquakes; the volcanic island, and the indian family. by mrs. baker. with six pages of engravings printed in tint, s. d. cloth, lettered, with richly coloured frontispiece;--or, s. sewed, with plain frontispiece. scripture natural history; by the rev. j. young, a.m. a pleasing description of the nature and habits of the most interesting and wonderful of the works of god, as exhibited in creation, and recorded in scripture. with numerous engravings, and eight pages of tinted illustrations; s. d. handsomely bound in cloth, gilt edges and sides. the orphan captive; or, christian endurance; a tale of the shipwreck and captivity of an ambassador's daughter. by miss j. strickland. with seven pages of elegant plates, s. sewed, or is. d. cloth. scripture parables, in easy verse, for children; with an explanation of each parable, in prose. by the author of ruth and naomi,--the widow's cruise of oil,--isaac and rebekah, &c. illustrated with eight pages of beautiful plates, and twenty engravings on wood. s. d. cloth lettered, with richly coloured frontispiece; or, s. sewed, in fancy covers, with plain frontispiece. tales of spring flowers and summer blossoms; for the young and good: about snow-drops,--the wall-flower,--and cowslips and primroses. with six pages of illustrations, s. sewed--or s. d. bound in cloth, lettered, and coloured frontispiece. more tales of spring flowers and summer blossoms; for the young and good: about hare bells,--the bee orchis,--white violets,--water lilies,--wild roses,--and wood anemonies. with six pages of illustrations, s. sewed;--or s. d. in cloth, lettered, and coloured frontispiece. the two parts, elegantly bound in one handsome volume, gilt edges, with eleven pages of tinted illustrations, s. d. the village school: with the history, and what became of, some of its scholars. s. d. cloth, with many engravings, and richly coloured frontispiece; or, s. sewed, with plain frontispiece. the widow and orphans; or, changes of life. by the rev. j. young, m.a. author of perils of paul percival. scripture natural history, &c. with seven pages of plates, and vignette title, s. sewed; or s. d. bound in cloth, with richly coloured frontispiece. little stories about pretty little birds. by the author of keeper's travels, &c. with seven pages of plates, and vignette title, s. sewed; or, with coloured frontispiece, s. d. bound in cloth. little tales for the nursery; amusing and instructive. by the author of 'sketches of little girls,' 'little boys,' &c. with many illustrations. s. d. cloth lettered, and richly coloured frontispiece; or, s. sewed, with plain frontispiece. stories of the five divisions of the world; descriptive of the peculiar habits and customs of the inhabitants of australia and polynesia,--omoko, king of africa,--the elephant, and the little dog of siam,--the american slave trade,--and europe, or, english freedom. with neat vignettes, and six tinted engravings s. sewed. stories of the five senses; or, which is best? an entertaining little book, for little ladies and little gentlemen. vignette illustrations, and six tinted engravings, s. sewed. which is best? or, stories about the five senses, and the five divisions of the globe with sixteen illustrations s. d. fancy cloth, gilt edges. the world's fair; or, children's prize gift book of the great exhibition of . describing the beautiful inventions and manufactures exhibited there; with pretty stories about the people who have made and sent those beautiful articles to be exhibited, and how they live when at home.--embellished with numerous elegant engravings, a frontispiece, and pictorial title-page. s. d. elegantly bound in cloth. sunshine and showers; or, stories for the children of england; by m.e.t. author of "silver blossoms to produce golden fruit."--embellished with illustrative engravings, and eight pages of plates, beautifully printed in lithography. s. d. elegantly bound in cloth. illustrated juvenile keepsake of amusement and instruction. with upwards of sixty engravings. s. sewed,--or s. d. bound in cloth, lettered. sketches of little boys; the well-behaved little boy. the attentive, inattentive, covetous dilatory, exact, quarrelsome, and good little boy. by s. lovechild. s. sewed,--square size, with seven coloured engravings. sketches of little girls; the good-natured little girl, the thoughtless, the vain, the orderly, the slovenly, the snappish, the persevering, the forward, the modest, and the awkward, little girl. by solomon lovechild. s. sewed,--square size, with seven coloured engravings. the three baskets, or, the little gardener, little painter, and little carpenter describing how, and in what manner, henry, richard, and charles, were occupied during the absence of their father. by mrs. burden. s. sewed,--square size, with seven coloured engravings. dame wiggins of lee, and her wonderful cats; a humorous tale, about the worthy old dame and her seven whiskered favourites: written by a lady of ninety. s. sewed,--square size, with fifteen coloured engravings. easy and interesting histories, for little folks; by miss corner, author of the historical library, &c. _price sixpence each, printed in large type, and embellished with four pages of descriptive tinted plates, and sewed in fancy wrappers._ the ancient britons. describing their manners and customs; and how they were conquered, and britain was governed by the romans. d. the conquest of the romans and britons by the saxons; and an interesting account of the saxon heptarchy, or the seven saxon kingdoms in england at one time. d. with four pages of illustrations. the life and times of alfred the great. an interesting narrative. d. four pages of illustrations. the norman conquest; four pages of illustrations. and the manner in which the people of england lived during the reign of william the conqueror. an interesting narrative. d. england, and its people in the feudal times. d. four pages of illustrations the history of england; with the manners and condition of the people in the middle ages. d. with four pages of illustrations. an interesting description of england in the sixteenth and seventeenth centuries. showing the condition of the people, and how they lived and dressed during the reign of henry the seventh, to the death of william the third. d. four pages of illustrations. an interesting description of england in the eighteenth and nineteenth centuries. showing the condition of the people, their modes of life, and how they lived and dressed from the reign of james the second, to that of queen victoria. d. four pages of illustrations. _these eight histories may be had, bound in one volume, in fancy cloth, gilt sides and edges, suitable for a present, price s. d._ * * * * * pleasant tales for little people, six-pence each,--sewed in fancy covers, printed in colors, _each embellished with numerous engravings on wood._ squire gray's fruit feast. with an account of how he entertained his young friends; and some of the pretty tales he gave to them as prizes. d. fourteen engravings. mirthful moments; or, how to enjoy holidays. a collection of mirthful and pleasing games and forfeits: with plain directions for playing each game, and how to cry the forfeits. d. with appropriate engravings. anne and jane; or, good advice and good example. a tale for young children. by miss j. strickland. d. fifteen engravings. sunshine and twilight; or, the prosperity and adversity of two cousins. exhibiting the sure reward of amiable manners and good conduct. d. fifteen engravings. troubles arising from being too late; or the two sisters. d. nineteen engravings. a prince in search of a wife; or, rosetta and the fairy.--a trial of charity. d. fifteen engravings. charity wood, the little orphan. a tale for young children. by miss jane strickland. d. many engravings. the little traveller's travellings in europe. d. sixteen engravings. * * * * * nursery picture books,--in illustrated covers, _size to. royal,--five sheets of coloured plates in each book._ the five divisions of the globe:--europe, asia, africa, america, and polynesia or australia. illustrated for little folks, on five large plates: and done up in a fancy cover, price s. plain; or, s. d. coloured. the four elements:--or, fire, air, earth, and water. illustrated for little folks. and the old english nursery rhyme of simple simon, set to music. on five large plates; and done up in a fancy cover. price s. plain; or, s. d. coloured. the five senses,--hearing, seeing, smelling, tasting, and feeling. and the four seasons,--spring, summer, autumn and winter. illustrated for little folks, on five large plates; and done up in a fancy cover. s. plain; or, s. d. coloured the nursery rhymes of old england, set to music, for little folks. containing, the queen of hearts,--bye! baby bunting,--who comes here? a grenadier!--little boy blue,--and, the lion and the unicorn. illustrated on five large plates; and done up in fancy cover. price s. plain; or, s. d. coloured. the royal nursery picture book,--the nursery alphabet,--the royal family.--the comparative sizes of animals,--and a "morland." s. plain; or, s. d. coloured. pleasant tales for little people. an interesting collection of amusing and instructive stories, for young persons. with upwards of eighty superior engravings, s. d. bound in fancy green cloth, with gilt edges and side. visit to the zoological gardens, regent's park. a pleasing description of this delightful place of fashionable resort, and of the nature and peculiar habits of the many rare and remarkable animals contained therein. by j. bishop. square size, with coloured engravings, and cuts of the animals. s. bound in cloth. a gift to young friends; or, the guide to good; about the good man of the mill,--from whom all good things come--the lost purse,--self-will,--the careless boy,--the good boy,--and the way to save. in words of one syllable. by miss corner. square size, with seven coloured engravings.-- s. in cloth. short tales in short words, about the lame boy,--the sea shore,--the cross boy,--and the stray child. by mrs. burden. square size, with seven coloured engravings.-- s. in cloth. little child's alphabet of nouns, or book of objects: the letters in large and small characters; each letter illustrated by a number of pleasing engravings of objects expressive of the letter.-- in large to., with the engravings neatly coloured. geographical alphabet; a new and pleasing introduction to a knowledge of some of the most celebrated places, or interesting countries, of the habitable world. by b. clayton. in large to., with twenty-six coloured engravings. peter pallette's pictures for painting: thirteen numbers, price d. each; or bound in vols, st series, s. d. nd series, s. d. worret's new outline drawing-book; a series of progressive lessons, by which the principles of the art, as applied to figure, ornamental, and mechanical drawing, may be easily and correctly acquired.--on stone, by w. heath. s. the set of six numbers; or s. d. in cloth. every child's drawing-book; easy and familiar subjects by heath and barfoot. in seven progressive numbers. s. the set. young artist's drawing-book of easy subjects, in lithography and ink. by barfoot and heath. in numbers. s. the set. =grandpapa easy's coloured= original and splendid pictorial toy books, six-pence each. size, large octavo super-royal. grandpapa easy's little pig's ramble from home. embellished with eight coloured engravings. grandpapa easy's laughable story about tom pepper. with twenty coloured engravings. grandpapa easy's two sisters; or, who would not be industrious? eight coloured engravings. grandpapa easy's 'little gentleman,'--general tom thumb. with eight coloured engravings. grandpapa easy's new mother goose and the golden eggs. eight coloured engravings. grandpapa easy's lady golightly and her cousins the grasshoppers; with nine coloured engravings. grandpapa easy's new story of the lion and the unicorn fighting for the crown. eight coloured engravings. grandpapa easy's pretty poetry, about trees, fruits, and flowers. with twenty-seven coloured engravings. grandpapa easy's jacko's merry method of learning the pence table. eight coloured engravings. grandpapa easy's pretty poetical spelling book. twenty-eight coloured engravings. grandpapa easy's countries of europe. embellished with fourteen coloured engravings. grandpapa easy's marquis of carabas; or, new puss in boots. with fifteen coloured engravings. grandpapa easy's amusing addition; a new poetical number book. sixteen coloured engravings. grandpapa easy's cock robin alive and well again; with seven coloured engravings. _all six-pence each,--with handsome coloured engravings._ =grandmamma easy's coloured= original and splendid pictorial toy books, six-pence each.--size, large octavo super royal. grandmamma easy's new stories about the alphabet. with twenty-six coloured engravings. grandmamma easy's merry multiplication. with seventeen coloured engravings. grandmamma easy's new story about old daddy longlegs. illustrated with eight coloured engravings. grandmamma easy's new story about little jack horner. with eight coloured engravings. grandmamma easy's michaelmas day, or, fate of poor molly goosey. eight coloured engravings. grandmamma easy's alderman's feast: a new alphabet. illustrated with eight coloured engravings. grandmamma easy's account of the public buildings of london. with twelve coloured engravings. grandmamma easy's wonders of a toy-shop. embellished with eight coloured engravings. grandmamma easy's new story of the queen of hearts. with eight coloured engravings. grandmamma easy's new story about little tom thumb and his mother. eight coloured plates. grandmamma easy's pretty stories about the elephant. embellished with eight coloured engravings. grandmamma easy's pretty stories about the camel. with nine coloured engravings. grandmamma easy's travels of little matty macaroni. with nine coloured engravings. grandmamma easy's dame bantry and her cat; a humourous tale; with seven coloured engravings. _all six-pence each,--with handsome coloured engravings._ =new series of original pictorial toy books,= six-pence each, with splendid coloured engravings. entitled =cousin honeycomb's= amusing multiplication; illustrated and explained, in twenty appropriate engravings. amusing substraction; rendered easy and plain by twenty-three appropriate engravings. amusing division, made familiar to the opening mind, by twenty-three appropriate engravings. amusing pence table; in a new, easy, and pleasing manner; with fifteen appropriate engravings. railway alphabet, shewing all that can be seen in railway travelling, exhibited in twenty-four engravings. alphabet of trades; exhibiting the working of the several trades, in forty-one descriptive engravings. new royal a, b, c, and spelling-book, in a new and familiar manner: with twenty-six pretty engravings, and twenty-six large ornamental coloured letters. pleasing popular rhymes for the nursery, or, the sayings and singings of infancy, in a new dress; ornamented with twenty-six humourous engravings. pleasing popular nursery riddles, and puzzles; upon the same plan as the above; thirty engravings. my aunt's ball; an alphabet; shewing who were there,--what they had,--and how they behaved themselves--with twenty-four engravings, a prince and his three gifts; how he used his three gifts; and about a good and beautiful lady; with eight large engravings. story of little joey, who came up to london a poor little boy, and afterwards became a great man;--with ten engravings. tales of the months and seasons: and what we see and enjoy all the year round; with twelve engravings. the mouse and her sons; a rural tale;--with eight coloured engravings. =uncle buncle's original toy books,= six-pence each. embellished with large appropriate colored engravings, and in fancy covers, * * * * * uncle buncle's death and burial of poor cock robin, and the trial of the sparrow for shooting him. with seven coloured engravings. uncle buncle's new story about master nobody, and his many wonderful exploits. coloured engravings. uncle buncle's visit to little johnny green, the best little boy that ever was seen: with coloured engravings. uncle buncle's two little cottage children, and the means by which they became rich. seven coloured engravings. uncle buncle's alphabet of objects. embellished with many coloured plates. uncle buncle's new a, b, c. with fourteen pretty and appropriate coloured pictures. uncle buncle's new stories about animals. seven coloured engravings. uncle buncle's comical boys, with fourteen coloured plates. uncle buncle's new stories about birds, seven coloured pictures. uncle buncle's lord mayor's show; a new and popular multiplication table: with fourteen coloured pictures of the procession by land and water. uncle buncle's story about the sick little robin, and his kind little nurse jenny wren. with seven coloured engravings. uncle buncle's stories about little peter's visit to the farm. with seven coloured engravings. =corner's historical library,= for youth, schools, and families: published by dean & son, , threadneedle street, london: comprising a complete history of every nation in europe, _uniformly printed, each country in a separate volume; with illustrations from historical subjects, elegantly engraven on steel, from designs by franklin, jones, and gilbert; and an accurate map to each volume; well bound in cloth, lettered;_ commencing with the earliest period of authentic record, and brought down to the present time: accurately pourtraying the national characteristics, and domestic habits, of the people. by miss corner, _author of "questions on the history of europe," a sequel to mangnall's historical questions, &c. &c._ the object of these works,--peculiarly suited to schools and families,--is to furnish the reader with a faithful history of each nation, interspersing it with an accurate account of the religion, laws, customs, national characteristics, and domestic habits of the people, in the various periods of their history. in writing these elementary treatises, one especial object has been kept in view--that of adapting them to the capacities of young people and occasional readers: by this means, while they embrace information and entertainment for all, they attract the rising generation, by simplicity of language, and clearness of detail, and render comparatively easy the attainment of a knowledge of the leading events of history. the many high encomiums awarded to these works by the public press, and the very considerable acceptance they have met with in schools and families, are proofs that the efforts of the author to render historical knowledge pleasing, and easy of attainment, are not unappreciated by those to whom the care of the rising generation is entrusted. these series of histories, by miss corner, comprise the following: the history of england; a new edition; with chronological table; twentieth thousand; _s_. _ d_. cloth, lettered; or bound up with questions on the history, _s_. illustrated with a map, and five historical engravings,-- . rowena presenting wine to vortigern. . king john signing magna charta. . henry vii. proclaimed at the battle of bosworth field. . oliver cromwell dissolving the long parliament. . coronation of queen victoria--the peers rendering homage. "it is important that history meant for young englishmen should be free from political poison, and this book will be found unexceptionable on this score."--_british banner_. "we have much pleasure in stating that this book is in another new edition, and its merits deserve it; it is well written, and admirably adapted for a school or reward book."--_academic and collegiate circular_. "miss corner's england and wales, we perceive, has just reached another new edition, in which the addition of the chronological table will be a great desideratum; the work is well written, and is equally adapted for a school, or, indeed, a gift book."--_bent's literary advertiser_. "we know no histories more likely to prove useful and agreeable in the instruction of children."--_britannia_. "the style of the book throughout renders it worthy of the support it has secured."--_gospel magazine_. "miss corner has chosen her epochs skilfully, and sketched them in a manner to make an adequate impression."--_literary gazette_. the history of ireland; new edition; seventh thousand; _ s. d._ cloth, lettered; or bound up with questions on the history, _s_. illustrated with a map, and three historical engravings.-- . st. patrick preaching christianity to the king and nobles. . lord thomas fitzgerald renouncing his allegiance to henry viii. . entry of james ii. into dublin. "the history before us is well executed."--_literary gazette_. "miss corner's style of writing will produce habits of thinking."--_morning advertiser_. "the historical facts, always correct, are detailed in plain and concise language. this is one of the best class books on ireland, for young people."--_limerick standard_. the beauty of composition throughout the writings of miss corner is singular and fascinating.--_sun_. miss corner has acquired a deserved celebrity for the singularly-attractive and intelligible manner she has in narrating history.--_critic_. the history of scotland; new edition; ninth thousand; s. d. cloth, lettered; or bound up with questions on the history, s. illustrated with a map, and three historical engravings.-- . coronation of the infant king david ii. and his queen, at scone. . james v. taking refuge at sterling castle. . queen mary's escape to england. "we sincerely recommend this history as peculiarly suited to the meridian of schools."--_ayr observer._ "this meritorious work is written in a very easy and agreeeble style, perfectly adapted to the capacities of the young persons for whom it is intended."--_times_. "we have perused this history with much interest, delighted with the ease and perspicuity of style, and with the clearness and force of the narrative."--_edinburgh chronicle._ "peculiarly adapted for instructive family reading."--_caledonian mercury._ the history of rome; from accepted english and foreign authorities, as macpherson's annals of commerce, keightley's roman history, smith's and adam's greek and roman antiquities; dr. arnold, niebuhr, &c. with questions to each chapter, a chronological table, and a map of the roman empire; s. d. bound in cloth, lettered. "miss corner's history of rome will assuredly ere long supersede all the roman histories at present used in schools, it is well written, and the historical facts elicited by the learned labours of niebuhr, arnold, &c, are made to take the place of the fabulous accounts which have hitherto passed current as authentic history; at the same time the popular early legends are not omitted, but their doubtful nature pointed out."--_westmister review._ "an excellent feature in this history is the continual effort to open out to the young reader the household life and social customs of the romans, for without this, ancient history can have no reality for children."--_educational times._ "its contents form a correct history of the roman empire, from its beginning."--_church of england journal._ the histories of spain and portugal; new edition, fifth thousand; s. d. cloth, lettered; or bound up with questions on the histories, s. illustrated with a map, and three historical engravings,-- . inez de castro entreating the king to save her life. . interview of columbus with queen isabella. . the cortez taking the oath of allegiance. "miss corner gives a clear and striking account of the different kingdoms that at various times were founded in spain."--_edinburgh review._ "so concise and plain as to be at once adapted to the capacities and volatility of young people, while they are useful compendiums for adults."--_times_. the history of france; tenth thousand, new edition, with continuation of events to the presidency of louis napoleon bonaparte; _s_ _d_. cloth, lettered; or bound up with questions on the history, _s_. illustrated with a map, and three historical engravings,-- . the coronation of charles vii. . a french tilt, or tournament. . bonaparte's expedition across the alps. "the writer has borne in mind throughout, that simplicity of style was essential to her purpose, and has selected those facts which are best adapted to give an idea of the events and the customs of the successive ages."--_baptist magazine_. "miss corner appears to be an excellent historian for the school room. she narrates with fluency and clearness, and in a concise and lively manner, the leading facts, so as to convey the spirit of history, and indicate the characteristics of the people and the country, as well as the rulers and famous characters."--_spectator_. "we look upon miss corner's work with great interest, as being peculiarly adapted to the minds of young people, and being free from that inversion of facts by which history is so often made subservient to party purposes."--_nonconformist_. the history of denmark, sweden, and norway; _s_. _d_. cloth, lettered; with a map, and two elegant historical engravings. . a norwegian family listening to the songs of their scalds, . submission of the order of nobles to frederick iii. "the two chief qualities of a good book are usefulness of subject and cleverness of handling, and these requisites miss corner's histories exhibit in an eminent degree. the frequent intermixtures of government between the three countries have indeed tended materially to embarrass this portion of european history, but miss corner by an accurate arrangement of dates, and a judicious connection of events, has set every thing in a clear light."--_post magazine._ the history of poland and russia; _s_. _d_. cloth, lettered; with a map, and three elegant historical engravings. . assassination of demetrius. . john cassimer, worn out by misfortune, resigning his crown to the diet. . flight of the inhabitants of moscow at the approach of the french army. "this volume forms one of a series of histories for the use of young persons; the present volume is, however, more descriptive than historical, which we consider an advantage; the living manners of the poles and russians being much more instructive and entertaining to young english readers."--_tait's magazine_. "miss corner has succeeded in compressing into a small compass all the leading events of history, without the slightest obscurity, or without sinking her book into a dry chronicle of facts."--_britannia_. the history of turkey and the ottoman empire; including greece, syria, and the holy land; _s_. _d_. cloth, lettered; with a map, and three elegant engravings. . selim ii., receiving the ambassadors of maximilian, emperor of germany. . mahomet expounding the koran at medina. . reschid pacha reading the hatti scheriff of to the ambassadors and great officers of state. "the narrative is so well arranged and so agreeably diversified by occasional remarks on individual and national character, as to render history attractive even to the very young; and the information is conveyed in a style remarkable for its unaffected simplicity and clearness."--_morning post._ "the leading features of turkish manners, laws, and policy, are accurately and forcibly pourtrayed, while the narrative is distinguished for simplicity, perspicuity, and completeness." _conservative journal._ the history of italy and switzerland; _s_. _d_. cloth, lettered; with a map, and three elegant historical engravings. . pope martin v, riding through the streets of rome, the emperor and elector leading his horse. . massaniello haranguing the populace. . william tell and the other swiss patriots holding their nightly meetings. "brief, clear, and correct; well adapted for young persons."--_leamington spa chronicle._ "written with great care and ability."--_john bull._ "a very useful educational book."--_literary gazette._ the history of holland and belgium; _s_. _d_. cloth, lettered, with a map, and two elegant historical engravings. . assassination of william of orange. . admiral van tromp shot whilst animating his sailors. "the present, like the preceeding histories from the pen of this intelligent lady, is distinguished for its conciseness, elegance of expression, and clearness of detail."--_manchester times._ "a condensed mass of knowledge, well put together, and prettily illustrated."--_church and state gazette._ "to a pleasing, fluent, narrative style, miss corner unites a nice discrimination, and never suffers matters which sully the mind to appear in her pages."--_surplice_. "we cannot too strongly recommend these admirable histories, and we feel satisfied that no parent or preceptor can place better works in the hands of a youth."--_academic and collegiate circular._ "altogether we do not know of a more agreeable or instructive present for youth; and each history is illustrated with a map and engravings, which considering the price of the work, are of a superior description."--_times_. "the authoress shows much discrimination in conveying in language suited to her readers the results of the laborious investigations of other scholars."--_educational times._ an accurate history of greece. from accepted authorities, english and foreign; as grote's and chambers's histories of greece, smith's greek and roman antiquities, thirlwall and wordsworth's greece, smith's mythology and biography, annals of commerce, library of useful knowledge, &c. with questions to each chapter, a chronological table, index, and a coloured map of the greek states. price _s_. bound in cloth, lettered. we have not met with any history of greece that contains, within the same compass, so large an amount of interesting and valuable information. miss corner writes concisely, perspicuously, and sensibly.--_westley banner._ a concise history of greece, well adapted for schools.--_cambridge independent press._ this is a very excellent compendium of grecian history, and such are the merits of the work that we shall not be surprised at its becoming a popular educational book.--_the british mother's magazine._ remarkably clear in its arrangement, while the simple and easy style in which it is written, peculiarly fits it for popular use, it displays much careful resourch on the part of its author.--_englishwoman's magazine._ miss corner has the art of writing so as to be understood by youthful readers.--_london literary journal._ by far the best introductory school history of greece we have ever seen.--_the british banner._ a combination of simplicity of narrative, with comprehensiveness of detail, admirably adapted for the use of the school-room.--_douglas jerrald's weekly news._ with feminine delicacy, miss corner omits what should be omitted, giving meanwhile a narrative of the broad character and features that mark the progress of a nation.--_express, evening paper._ the results of the best modern scholarship are here given.--_leader_. miss corner's histories require no recommendation of ours to bring them into notice. this volume, her history of greece, is written with great clearness and fluency, the fabulous tales which disfigure so many professedly authentic histories of the greeks are discarded. we cordially recommend this work for the school-room, or family circle.--_gospel herald._ religious works published by thomas dean and son, threadneedle-street. * * * * * dedicated (by permission) to the lord bishop of lincoln. the rev^d. edward bickersteth's christian psalmody; 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for, behold, i bring you good tidings of great joy. luke, ii. . adoration of the magi. and when they saw the young child with mary his mother, they fell down, and worshipped him. matthew, ii. . christ disputing with the doctors. they found him in the temple, sitting in the midst of the doctors, both hearing them, and asking them questions. luke, ii, . the baptism of christ. the heavens were opened unto him, and he saw the spirit of god descending like a dove, and lighting upon him, matt. iii. . christ blessing little children. suffer the little children to come unto me, and forbid them not; for of such is the kingdom of heaven. mark, x, . christ healing the blind. jesus said unto him, receive thy sight; thy faith hath saved thee. luke, xviii. . the raising of lazarus. he cried with a loud voice, lazarus, come forth. and he that was dead came forth, bound head and foot. john, xi. . the widow's mite. this poor widow hath cast more in, than all they which have cast into the treasury,--for she did cast in all that she had. mark, xii. . christ's entry into jerusalem. many spread their garments in the way; others cut down branches from the trees, and strewed them in the way. mark, xi. . the last supper. this do in remembrance of me. luke, xxii. . peter denying christ. and the lord turned, and looked upon peter, and peter remembered the words of the lord, before the cock crows, thou shalt deny me thrice. and he wept bitterly luke, xxii, l. christ before pilate. pilate asked him, answerest thou nothing? behold how many things they witness against thee. mark, xv. . taking down from the cross. when joseph had taken the body, he wrapped it in a clean linen cloth, and laid it in his own new tomb. matthew, xxvii. . * * * * * amusing panoramas of animals,--with their uses and habits,--for children.--eight animals, with characteristic coloured engravings, in each book. sorts, d. each. peter palette's coloured scrap book; in six parts, each part comprising six leaves, and each leaf containing several interesting subjects.--six-pence each part;--or the set, bound together, s. d. the child's own scrap book of pictures, by peter palette. seven parts, coloured; 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[illustration] scientific american supplement no. new york, june , scientific american supplement. vol. xvii., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. chemistry and metallurgy.--on electrolysis.--precipitation of lead, thallium, silver, bismuth, manganese, etc.--by h. schucht the electro-chemical equivalent of silver zircon.--how it can be rendered soluble.--by f. stolba a new process for making wrought iron directly from the ore. --comparison with other processes.--with descriptions and engravings of the apparatus used some remarks on the determination of hardness in water on the changes which take place in the conversion of hay into ensilage.--by f.j. lloyd ii. engineering and mechanics.--faure's machine for decorticating sugar cane.--with full description and figures the generation of steam and the thermodynamic problems involved.--by wm. anderson.--apparatus used in the experimental determination of the heat of combustion and the laws which govern its development.--ingredients of fuel.--potential energy of fuel.--with figures and several tables planetary wheel trains.--rotations of the wheels relatively to the train arm.--by prof. c.w. maccord the pantanemone.--a new windwheel.-- engraving relvas's new life boat.--with engraving experiments with double barreled guns and rifles. --cause of the divergence of the charge.-- figures improved ball turning machine.-- figure cooling apparatus for injection water.--with engraving corrugated disk pulleys.-- engraving iii. technology.--a new standard light dr. feussner's new polarizing prism.--points of difference between the old and new prisms.--by p.r. sleeman density and pressure of detonating gas iv. electricity, light, etc.--early history of the telegraph. --pyrsia, or the system of telegraphy among the greeks. --communication by means of characters and the telescope. --introduction of the magnetic telegraph between baltimore and washington the kravogl electro motor and its conversion into a dynamo electric machine.-- figures bornhardt's electric machine for blasting in mines. -- figures pritchett's electric fire alarm.-- figure a standard thermopile telephonic transmission without receivers.--some of the apparatus exhibited at the annual meeting of the french society of physics.--telephonic transmission through a chain of persons diffraction phenomena during total solar eclipses.--by g.d. hiscox v. botany and horticulture.--gum diseases in trees.-- cause and contagion of the same drinkstone park.--trees and plants cultivated therein.-- with engravings vi. medicine and hygiene.--miryachit.--a newly-discovered disease of the nervous system, and its analogues.--by wm. a. hammond vii. miscellaneous.--turkish baths for horses.--with diagram. * * * * * faure's machine for decorticating sugar-cane. the object of the apparatus shown in the accompanying engraving is to effect a separation of the tough epidermis of the sugar-cane from the internal spongy pith which is to be pressed. its function consists in isolating and separating the cells from their cortex, and in putting them in direct contact with the rollers or cylinders of the mill. after their passage into the apparatus, which is naturally placed in a line with the endless chain that carries them to the mill, the canes arrive in less compact layers, pass through much narrower spaces, and finally undergo a more efficient pressure, which is shown by an abundant flow of juice. the first trials of the machine were made in at the pointe simon works, at martinique, with the small type that was shown at the paris exhibition of . these experiments, which were applied to a work of , kilos of cane per hour, gave entire satisfaction, and decided the owners of three of the colonial works (pointe simon, larcinty, and marin) to adopt it for the season of . the apparatus is shown in longitudinal section in fig. , and in plan in fig. . fig. gives a transverse section passing through the line - , and fig. an external view on the side whence the decorticated canes make their exit from the apparatus. [illustration: faure's machine for decorticating sugar cane.] the other figures relate to details that will be referred to further along. _the decorticating cylinder._--the principal part of the apparatus is a hollow drum, a, of cast iron, mm. in internal diameter by . m. in length, which is keyed at its two extremities to the shaft, a. externally, this drum (which is represented apart in transverse section in fig. ) has the form of an octagonal prism with well dressed projections between which are fixed the eight plates, c, that constitute the decorticating cylinder. these plates, which are of tempered cast iron, and one of which is shown in transverse section in fig. , when once in place form a cylindrical surface provided with helicoidal, dentate channels. the length of these plates is mm. there are three of them in the direction of the generatrices of the cylinder, and this makes a total of . all are strengthened by ribs (as shown in fig. ), and each is fixed by bolts, _c_, mm. in diameter. the pitch of the helices of each tooth is very elongated, and reaches about . m. the depth of the toothing is mm. _frame and endless chain._--the cylinder thus constructed rotates with a velocity of revolutions per minute over a cylindrical vessel, b', cast in a piece with the frame, b. this vessel is lined with two series of tempered cast iron plates, d and d', called exit and entrance plates, which rest thereon, through the intermedium of well dressed pedicels, and which are held in place by six -millimeter bolts. their length is mm. the entrance plates, d, are provided with spiral channels, whose pitch is equal to that of the channels of the decorticating cylinder, c, and in the same direction. the depth of the toothing is mm. the exit plates, d', are provided with spiral channels of the same pitch and direction as those of the preceding, but the depth of which increases from to mm. the axis of the decorticating cylinder does not coincide with that of the vessel, b', so that the free interval for the passage of the cane continues to diminish from the entrance to the exit. the passage of the cane to the decorticator gives rise to a small quantity of juice, which flows through two orifices, _b'_, into a sort of cast iron trough, g, suspended beneath the vessel. the cane, which is brought to the apparatus by an endless belt, empties in a conduit formed of an inclined bottom, e, of plate iron, and two cast iron sides provided with ribs. these sides rest upon the two ends of the vessel, b', and are cross-braced by two flat bars, _e_, to which is bolted the bottom, e. this conduit is prolonged beyond the decorticating cylinder by an inclined chute, f, the bottom of which is made of plate iron mm. thick and the sides of the same material mm. thick. the hollow frame, b, whose general form is like that of a saddle, carries the bearings, _b_, in which revolves the shaft, _a_. one of these bearings is represented in detail in figs. and . it will be seen that the cap is held by bolts with sunken heads, and that the bearing on the bushes is through horizontal surfaces only. in a piece with this frame are cast two similar brackets, b², which support the axle, _h_, of the endless chain. to this axle, whose diameter is mm., are keyed, toward the extremities, the pinions, h, to which correspond the endless pitch chains, _i_. these latter are formed, as may be seen in figs. and , of two series of links. the shorter of these latter are only mm. in length, while the longer are mm., and are hollowed out so as to receive the butts of the boards, i. the chain thus formed passes over two pitch pinions, j, like the pinions, h, that are mounted at the extremities of an axle, _j_, that revolves in bearings, i', whose position with regard to the apparatus is capable of being varied so as to slacken or tauten the chain, i. this arrangement is shown in elevation in fig. . _transmission._--the driving shaft, _k_, revolves in a pillow block, k, cast in a piece with the frame, b. it is usually actuated by a special motor, and carries a fly-wheel (not shown in the figure for want of space). it receives in addition a cog-wheel, l, which transmits its motion to the decorticating cylinder through, the intermedium of a large wooden-toothed gear wheel, l'. the shaft, _a_, whose diameter is mm., actuates in its turn, through the pinions, m' and m, the pitch pinion, n, upon whose prolonged hub is keyed the pinion, m. this latter is mounted loosely upon the intermediate axle, _m_. motion is transmitted to the driving shaft, _h_, of the endless chain, i, by an ordinary pitch chain, through a gearing which is shown in fig. . the pitch pinion, n', is cast in a piece with a hollow friction cone, n², which is mounted loosely upon the shaft, _h_, and to which corresponds a second friction cone, o. this latter is connected by a key to a socket, _o_, upon which it slides, and which is itself keyed to the shaft, _h_. the hub of the cone, o, is connected by a ring with a bronze nut, _p_, mounted at the threaded end of the shaft, _h_, and carrying a hand-wheel, p. it is only necessary to turn this latter in one direction or the other in order to throw the two cones into or out of gear. if we allow that the motor has a velocity of revolutions per minute, the decorticating cylinder will run at the rate of , and the sugar-cane will move forward at the rate of meters per minute. this new machine is a very simple and powerful one. the decortication is effected with wonderful rapidity, and the canes, opened throughout their entire length and at all points of their circumference, leave the apparatus in a state that allows of no doubt as to what the result of the pressure will be that they have to undergo. there is no tearing, no trituration, no loss of juice, but merely a simple preparation for a rational pressure effected under most favorable conditions. the apparatus, which is made in several sizes, has already received numerous applications in martinique, trinidad, cuba, antigua, st. domingo, peru, australia, the mauritius islands, and brazil.--_publication industrielle._ * * * * * moving a bridge. an interesting piece of engineering work has recently been accomplished at bristol, england, which consisted in the moving of a foot-bridge feet in length, bodily, down the river a considerable distance. the pontoons by means of which the bridge was floated to its new position consisted of four -ton barges, braced together so as to form one solid structure feet in width, and were placed in position soon after the tide commenced to rise. at six o'clock a.m. the top of the stages, which was feet above the water, touched the under part of the bridge, and in a quarter of an hour later both ends rose from their foundations. when the tide had risen ft. the stage and bridge were floated to the new position, when at . the girders dropped on to their beds. * * * * * the generation of steam, and the thermodynamic problems involved.[ ] [footnote : lecture delivered at the institution of civil engineers, session - . for the illustrations we are indebted to the courtesy of mr. j. forrest, the secretary.] by mr. william anderson, m.i.c.e. it will not be necessary to commence this lecture by explaining the origin of fuel; it will be sufficient if i remind you that it is to the action of the complex rays of the sun upon the foliage of plants that we mainly owe our supply of combustibles. the tree trunks and branches of our forests, as well as the subterranean deposits of coal and naphtha, at one time formed portions of the atmosphere in the form of carbonic acid gas; that gas was decomposed by the energy of the solar rays, the carbon and the oxygen were placed in positions of advantage with respect to each other--endowed with potential energy; and it is my duty this evening to show how we can best make use of these relations, and by once more combining the constituents of fuel with the oxygen of the air, reverse the action which caused the growth of the plants, that is to say, by destroying the plant reproduce the heat and light which fostered it. the energy which can be set free by this process cannot be greater than that derived originally from the sun, and which, acting through the frail mechanism of green leaves, tore asunder the strong bonds of chemical affinity wherein the carbon and oxygen were hound, converting the former into the ligneous portions of the plants and setting the latter free for other uses. the power thus silently exerted is enormous; for every ton of carbon separated in twelve hours necessitates an expenditure of energy represented by at least , horse power, but the action is spread over an enormous area of leaf surface, rendered necessary by the small proportion of carbonic acid contained in the air, by measure only / part, and hence the action is silent and imperceptible. it is now conceded on all hands that what is termed heat is the energy of molecular motion, and that this motion is convertible into various kinds and obeys the general laws relating to motion. two substances brought within the range of chemical affinity unite with more or less violence; the motion of transition of the particles is transformed, wholly or in part, into a vibratory or rotary motion, either of the particles themselves or the interatomic ether; and according to the quality of the motions we are as a rule, besides other effects, made conscious of heat or light, or of both. when these emanations come to be examined they are found to be complex in the extreme, intimately bound up together, and yet capable of being separated and analyzed. as soon as the law of definite chemical combination was firmly established, the circumstance that changes of temperature accompanied most chemical combinations was noticed, and chemists were not long in suspecting that the amount of heat developed or absorbed by chemical reaction should be as much a property of the substances entering into combination as their atomic weights. solid ground for this expectation lies in the dynamic theory of heat. a body of water at a given height is competent by its fall to produce a definite and invariable quantity of heat or work, and in the same way two substances falling together in chemical union acquire a definite amount of kinetic energy, which, if not expended in the work of molecular changes, may also by suitable arrangements be made to manifest a definite and invariable quantity of heat. at the end of last century lavoisier and laplace, and after them, down to our own time, dulong, desprez, favre and silbermann, andrews, berthelot, thomson, and others, devoted much time and labor to the experimental determination of the heat of combustion and the laws which governed its development. messrs. favre and silbermann, in particular, between the years and , carried out a splendid series of experiments by means of the apparatus partly represented in fig. (opposite), which is a drawing one-third the natural size of the calorimeter employed. it consisted essentially of a combustion chamber formed of thin copper, gilt internally. the upper part of the chamber was fitted with a cover through which the combustible could be introduced, with a pipe for a gas jet, with a peep hole closed by adiathermanous but transparent substances, alum and glass, and with a branch leading to a thin copper coil surrounding the lower part of the chamber and descending below it. the whole of this portion of the apparatus was plunged into a thin copper vessel, silvered internally and filled with water, which was kept thoroughly mixed by means of agitators. this second vessel stood inside a third one, the sides and bottom of which were covered with the skins of swans with the down on, and the whole was immersed in a fourth vessel tilled with water, kept at the average temperature of the laboratory. suitable thermometers of great delicacy were provided, and all manner of precautions were taken to prevent loss of heat. [illustration: the generation of steam. fig .] it is impossible not to admire the ingenuity and skill exhibited in the details of the apparatus, in the various accessories for generating and storing the gases used, and for absorbing and weighing the products of combustion; but it is a matter of regret that the experiments should have been carried out on so small a scale. for example, the little cage which held the solid fuel tested was only / inch diameter by barely inches high, and held only grains of charcoal, the combustion occupying about sixteen minutes. favre and silbermann adopted the plan of ascertaining the weight of the substances consumed by calculation from the weight of the products of combustion. carbonic acid was absorbed by caustic potash, as also was carbonic oxide, after having been oxidized to carbonic acid by heated oxide of copper, and the vapor of water was absorbed by concentrated sulphuric acid. the adoption of this system showed that it was in any case necessary to analyze the products of combustion in order to detect imperfect action. thus, in the case of substances containing carbon, carbonic oxide was always present to a variable extent with the carbonic acid, and corrections were necessary in order to determine the total heat due to the complete combination of the substance with oxygen. another advantage gained was that the absorption of the products of combustion prevents any sensible alteration in the volumes during the process, so that corrections for the heat absorbed in the work of displacing the atmosphere were not required. the experiments on various substances were repeated many times. the mean results for those in which we are immediately interested are given in table i., next column. comparison with later determinations have established their substantial accuracy. the general conclusion arrived at is thus stated: "as a rule there is an equality between the heat disengaged or absorbed in the acts, respectively, of chemical combination or decomposition of the same elements, so that the heat evolved during the combination of two simple or com-pound substances is equal to the heat absorbed at the time of their chemical segregation." table i.--substances entering into the composition of fuel. -----------------------+-------------+-----------+-------------------+ | | heat evolved in | | symbol and atomic |the combustion of | | weight. | lb. of fuel. | +------------+------------+--------+----------+ | | | |in pounds | | | | in | of water | | | |british |evaporated| | before | after |thermal | from and | | combustion | combustion | units. | at °. | +------------+------------+--------+----------+ hydrogen burned | h | h o | , | . | in oxygen. | | | | | -----------------------+------------+------------+--------+----------+ carbon burned to | c | co | , | . | carbonic oxide. | | | | | -----------------------+------------+------------+--------+----------+ carbon burned to | c | co | , | . | carbonic acid. | | | | | -----------------------+------------+------------+--------+----------+ carbonic oxide burned | co | co | , | . | to carbonic acid. | | | | | -----------------------+------------+------------+--------+----------+ olefiant gas (ethylene)| c h | co | , | . | burnt in oxygen. | | h o | | | -----------------------+------------+------------+--------+----------+ marsh gas (methane) | ch | co | , | . | burnt in oxygen. | | h o | | | -----------------------+------------+------------+--------+----------+ composition of air-- by volume . n + . o + . co + . h o ---------------------------------------------------- by weight . n + . o + . co + . h o this law is, however, subject to some apparent exceptions. carbon burned in protoxide of nitrogen, or laughing gas, n_{ }o, produces about per cent. more heat than the same substance burned in pure oxygen, notwithstanding that the work of decomposing the protoxide of nitrogen has to be performed. in marsh gas, or methane, ch_{ }, again, the energy of combustion is considerably less than that due to the burning of its carbon and hydrogen separately. these exceptions probably arise from the circumstance that the energy of chemical action is absorbed to a greater or less degree in effecting molecular changes, as, for example, the combustion of pound of nitrogen to form protoxide of nitrogen results in the absorption of , units of heat. berthelot states, as one of the fundamental principles of thermochemistry, "that the quantity of heat evolved is the measure of the sum of the chemical and physical work accomplished in the reaction"; and such a law will no doubt account for the phenomena above noted. the equivalent heat of combustion of the compounds we have practically to deal with has been experimentally determined, and therefore constitutes a secure basis on which to establish calculations of the caloric value of fuel; and in doing so, with respect to substances composed of carbon, hydrogen, and oxygen, it is convenient to reduce the hydrogen to its heat-producing equivalent of carbon. the heat of combustion of hydrogen being , units, that of carbon , units, it follows that . times the weight of hydrogen will represent an equivalent amount of carbon. with respect to the oxygen, it is found that it exists in combination with the hydrogen in the form of water, and, being combined already, abstracts its combining equivalent of hydrogen from the efficient ingredients of the fuel; and hence hydrogen, to the extent of / of the weight of the oxygen, must be deducted. the general formula then becomes: heat of combustion = , {c + . (h-(o/ ))}, and water evaporated from and at °, taking units as the heat necessary to evaporate pound of water, lb. evaporated = . {c + . (h-(o/ ))}, carbon, hydrogen, and oxygen being taken at their weight per cent. in the fuel. strictly speaking, marsh gas should be separately determined. it often happens that available energy is not in a form in which it can be applied directly to our needs. the water flowing down from the mountains in the neighborhood of the alpine tunnels was competent to provide the power necessary for boring through them, but it was not in a form in which it could be directly applied. the kinetic energy of the water had first to be changed into the potential energy of air under pressure, then, in that form, by suitable mechanism, it was used with signal success to disintegrate and excavate the hard rock of the tunnels. the energy resulting from combustion is also incapable of being directly transformed into useful motive power; it must first be converted into potential force of steam or air at high temperature and pressure, and then applied by means of suitable heat engines to produce the motions we require. it is probably to this circumstance that we must attribute the slowness of the human race to take advantage of the energy of combustion. the history of the steam engine hardly dates back years, a very small fraction of the centuries during which man has existed, even since historic times. the apparatus by means of which the potential energy of fuel with respect to oxygen is converted into the potential energy of steam, we call a steam boiler; and although it has neither cylinder nor piston, crank nor fly wheel, i claim for it that it is a veritable heat engine, because it transmits the undulations and vibrations caused by the energy of chemical combination in the fuel to the water in the boiler; these motions expend themselves in overcoming the liquid cohesion of the water and imparting to its molecules that vigor of motion which converts them into the molecules of a gas which, impinging on the surfaces which confine it and form the steam space, declare their presence and energy in the shape of pressure and temperature. a steam pumping engine, which furnishes water under high pressure to raise loads by means of hydraulic cranes, is not more truly a heat engine than a simple boiler, for the latter converts the latent energy of fuel into the latent energy of steam, just as the pumping engine converts the latent energy of steam into the latent energy of the pumped-up accumulator or the hoisted weight. if i am justified in taking this view, then i am justified in applying to my heat engine the general principles laid down in by sadi carnot, namely, that the proportion of work which can be obtained out of any substance working between two temperatures depends entirely and solely upon the difference between the temperatures at the beginning and end of the operation; that is to say, if t be the higher temperature at the beginning, and _t_ the lower temperature at the end of the action, then the maximum possible work to be got out of the substance will be a function of (t-_t_). the greatest range of temperature possible or conceivable is from the absolute temperature of the substance at the commencement of the operation down to absolute zero of temperature, and the fraction of this which can be utilized is the ratio which the range of temperature through which the substance is working bears to the absolute temperature at the commencement of the action. if w = the greatest amount of effect to be expected, t and _t_ the absolute temperatures, and h the total quantity of heat (expressed in foot pounds or in water evaporated, as the case may be) potential in the substance at the higher temperature, t, at the beginning of the operation, then carnot's law is expressed by the equation: / t - t \ w = h( ------- ) \ t / i will illustrate this important doctrine in the manner which carnot himself suggested. [illustration: the generation of steam. fig .] fig. represents a hillside rising from the sea. some distance up there is a lake, l, fed by streams coming down from a still higher level. lower down on the slope is a millpond, p, the tail race from which falls into the sea. at the millpond is established a factory, the turbine driving which is supplied with water by a pipe descending from the lake, l. datum is the mean sea level; the level of the lake is t, and of the millpond _t_. q is the weight of water falling through the turbine per minute. the mean sea level is the lowest level to which the water can possibly fall; hence its greatest potential energy, that of its position in the lake, = qt = h. the water is working between the absolute levels, t and _t_; hence, according to carnot, the maximum effect, w, to be expected is-- / t - t \ w = h( ------- ) \ t / / t - t \ but h = qt [therefore] w = q t( ------- ) \ t / w = q (t - t), that is to say, the greatest amount of work which can be expected is found by multiplying the weight of water into the clear fall, which is, of course, self-evident. now, how can the quantity of work to be got out of a given weight of water be increased without in any way improving the efficiency of the turbine? in two ways: . by collecting the water higher up the mountain, and by that means increasing t. . by placing the turbine lower down, nearer the sea, and by that means reducing _t_. now, the sea level corresponds to the absolute zero of temperature, and the heights t and _t_ to the maximum and minimum temperatures between which the substance is working; therefore similarly, the way to increase the efficiency of a heat engine, such as a boiler, is to raise the temperature of the furnace to the utmost, and reduce the heat of the smoke to the lowest possible point. it should be noted, in addition, that it is immaterial what liquid there may be in the lake; whether water, oil, mercury, or what not, the law will equally apply, and so in a heat engine, the nature of the working substance, provided that it does not change its physical state during a cycle, does not affect the question of efficiency with which the heat being expended is so utilized. to make this matter clearer, and give it a practical bearing, i will give the symbols a numerical value, and for this purpose i will, for the sake of simplicity, suppose that the fuel used is pure carbon, such as coke or charcoal, the heat of combustion of which is , units, that the specific heat of air, and of the products of combustion at constant pressure, is . , that only sufficient air is passed through the fire to supply the quantity of oxygen theoretically required for the combustion of the carbon, and that the temperature of the air is at ° fahrenheit = ° absolute. the symbol t represents the absolute temperature of the furnace, a value which is easily calculated in the following manner: lb. of carbon requires - / lb. of oxygen to convert it into carbonic acid, and this quantity is furnished by . lb. of air, the result being . lb. of gases, heated by , units of heat due to the energy of combustion; therefore: , units t = ° + ------------------ = , ° absolute. . lb. x . the lower temperature, _t_, we may take as that of the feed water, say at ° or ° absolute, for by means of artificial draught and sufficiently extending the heating surface, the temperature of the smoke may be reduced to very nearly that of the feed water. under such circumstances the proportion of heat which can be realized is , ° - ° = --------------- = . ; , ° that is to say, under the extremely favorable if not impracticable conditions assumed, there must be a loss of per cent. next, to give a numerical value to the potential energy, h, to be derived from a pound of carbon, calculating from absolute zero, the specific heat of carbon being . , and absolute temperature of air °: units. lb. of carbon x . x = . of air x . x = , heat of combustion = , ------ , deduct heat equivalent to work of \ displacing atmosphere by products of } combustion raised from ° to °, } or from . cubic feet to . } cubic feet, / ------ total units of heat available , equal to . lb. of water evaporated from and at °. hence the greatest possible evaporation from and at ° from a lb. of carbon-- , u. x . - u. w = --------------------------- = . lb. u. i will now take a definite case, and compare the potential energy of a certain kind of fuel with the results actually obtained. for this purpose the boiler of the eight-horse portable engine, which gained the first prize at the cardiff show of the royal agricultural society in , will serve very well, because the trials, all the details of which are set forth very fully in vol. ix. of the _journal_ of the society, were carried out with great care and skill by sir frederick bramwell and the late mr. menelaus; indeed, the only fact left undetermined was the temperature of the furnace, an omission due to the want of a trustworthy pyrometer, a want which has not been satisfied to this day.[ ] [footnote : in the fifty-second volume of the _proceedings_ ( - ), page , will be found a remarkable experiment on the evaporative power of a vertical boiler with internal circulating pipes. the experiment was conducted by sir frederick bramwell and dr. russell, and is remarkable in this respect, that the quantity of air admitted to the fuel, the loss by convection and radiation, and the composition of the smoke were determined. the facts observed were as follows: steam pressure lb................................... = . ° f. lb. fuel--water in coke and wood........................... . ash.............................................. . hydrogen, oxygen, nitrogen, and sulphur.......... . ------ total non-combustible..................... . carbon, being useful combustible................. . ------ total fuel................................ . air per pound of carbon................................ - / lb. time of experiment..................................... h. min. water evaporated from ° into steam at lb. pressure , lb. heat lost by radiation and convection.................. , units. mean temperature of chimney............................ ° f. " " " air................................ ° f. no combustible gas was found in the chimney. i will apply carnot's doctrine to this case. potential energy of the fuel with respect to absolute zero: units. . lb. × ° abs. × . ...................... = , . lb. × - / × ° × . , the weight and heat of air....................... , . × , units heat of combustion of carbon... , , --------- total energy , , heat absorbed in evaporating . lb. of water in fuel............................................ - , --------- available energy.......................... , , temperature of furnace-- the whole of the fuel was heated up, but the heat absorbed in the evaporation of the water lowered the temperature of the furnace, and must be deducted from the heat of combustion. units. heat of combustion................................... , , " " evaporation of . lb. water............... - , --------- available heat of combustion.............. , , dividing by . lb. gives the heat per lb. of fuel used................................... = , units. and temperature of furnace: , units/( . lb. × . ) + °......... = , ° temperature of chimney ° + °............... = , ° maximum duty ( , ° - , °)/ , °............ = . ° work of displacing atmosphere by smoke at °: cubic feet. volumes of gases at °........................ = . " " " " °........................ = . ----- increase of volume.................... . units. work done= ( . lb. × . cub. ft. × sq. in. × lb.) / units ..................................... = , maximum amount of work to be expected = , , × . .............................. = , , deduct work of displacing atmosphere............. = , --------- available work........................ , , actual work done: units. , lb. of water raised from ° and turned into steam at lb..... ...................... = , , loss by radiation and convection................. , - / lb. ashes left, say at °............... , --------- total work actually done.............. , , unaccounted for.................................. , --------- calculated available work........................ , , the unaccounted-for work, therefore, amounts to only ½ per cent. of the calculated available work. sir frederick bramwell ingeniously arranged his data in the form of a balance sheet, and showed , units unaccounted for; but if from this we deduct the work lost in displacing the air, the unaccounted-for heat falls to less than per cent. of the total heat of combustion. these results show how extremely accurate the observations must have been, and that the loss mainly arises from convection and radiation from the boiler.] the data necessary for our purpose are: steam pressure lb. temperature ° = ° absolute. mean temperature of smoke ° = ° " water evaporated per lb of coal, from and at ° . lb. temperature of the air ° = ° absolute. " of feed water ° = ° " heating surface square feet. grate surface . feet. coal burnt per hour lb. the fuel used was a smokeless welsh coal, from the llangennech colleries. it was analyzed by mr. snelus, of the dowlais ironworks, and in table ii. are exhibited the details of its composition, and the weight and volume of air required for its combustion. the total heat of combustion in lb of water evaporated: = . × ( . + . × ( . - . / )) = . lb. of water from and at ° = , units of heat. table ii.--properties of llangennech coal. ---------------------+----------+------------+---------------------+ | | | | | | | products of | | | oxygen | combustion at ° f.| | analyses | required +--------+------------+ | of lb. | for | | | | of coal. | combustion.| cubic | volume | | | pounds. | feet. | per cent. | ---------------------+----------+------------+--------+------------+ carbon........... | . | . | . | . | hydrogen......... | . | . | . | . | oxygen........... | . | --- | --- | --- | sulphur.......... | . | --- | --- | _ --- | nitrogen......... | . | --- | . | | | ash.............. | . | --- | --- | | | +----------+------------+ | | . | | | | | | | total........... | . | . | --- | | | - / .lb nitrogen | --- | --- | . | | | lb. excess of air. | --- | --- | . | _| | +----------+------------+--------+------------+ total cubic feet of | | | | | products per lb. | | | | | of coal........... | -- | -- | . | . | ---------------------+----------+------------+--------+------------+ the temperature of the furnace not having been determined, we must calculate it on the supposition, which will be justified later on, that per cent more air was admitted than was theoretically necessary to supply the oxygen required for perfect combustion. this would make lb. of air per lb. of coal; consequently lb. of gases would be heated by , units of heat. hence: , u. t = ---------------- = , ° lb. × . above the temperatures of the air, or , ° absolute. the temperature of the smoke, _t_, was ° absolute; hence the maximum duty would be , ° - ° --------------- = . . , ° the specific heat of coal is very nearly that of gases at constant pressure, and may, without sensible error, be taken as such. the potential energy of lb. of coal, therefore, with reference to the oxygen with which it will combine, and calculated from absolute zero, is: units. lb. of coal and air at the temperature of the air contained lb. × ° × . , heat of combustion , ------- , deduct heat expended in displacing atmosphere cubic feet - ------ total potential energy , hence work to be expected from the boiler: / , ° - ° \ = , units x ( --------------- ) - units \ , ° / ---------------------------------------------- = . lb. units of water evaporated from and at °, corresponding to , units. the actual result obtained was . lb.; hence the efficiency of this boiler was . ------- = . . . i have already claimed for a boiler that it is a veritable heat engine, and i have ventured to construct an indicator diagram to illustrate its working. the rate of transfer of heat from the furnace to the water in the boiler, at any given point, is some way proportional to the difference of temperature, and the quantity of heat in the gases is proportional to their temperatures. draw a base line representing - ° fahr., the absolute zero of temperature. at one end erect an ordinate, upon which set off t = , °, the temperature of the furnace. at ° = _t_, on the scale of temperature, draw a line parallel to the base, and mark on it a length proportional to the heating surface of the boiler; join t by a diagonal with the extremity of this line, and drop a perpendicular on to the zero line. the temperature of the water in the boiler being uniform, the ordinates bounded by the sloping line, and by the line, _t_, will at any point be approximately proportional to the rate of transmission of heat, and the shaded area above _t_ will be proportional to the quantity of heat imparted to the water. join t by another diagonal with extremity of the heating surface on the zero line, then the larger triangle, standing on the zero line, will represent the whole of the heat of combustion, and the ratio of the two triangles will be as the lengths of their respective bases, that is, as (t - _t_) / t, which is the expression we have already used. the heating surface was square feet, and it was competent to transmit the energy developed by lb. of coal consumed per hour = , u. × u. = , units, equal to an average of , units per square foot per hour; this value will correspond to the mean pressure in an ordinary diagram, for it is a measure of the energy with which molecular motion is transferred from the heated gases to the boiler-plate, and so to the water. the mean rate of transmission, multiplied by the area of heating surface, gives the area of the shaded portion of the figure, which is the total work which should have been done, that is to say, the work of evaporating lb. of water per hour. the actual work done, however, was only lb. to give the speculations we have indulged in a practical turn, it will be necessary to examine in detail the terms of carnot's formula. carnot labored under great disadvantages. he adhered to the emission theory of heat; he was unacquainted with its dynamic equivalent; he did not know the reason of the difference between the specific heat of air at constant pressure and at constant volume, the idea of an absolute zero of temperature had not been broached; but the genius of the man, while it made him lament the want of knowledge which he felt must be attainable, also enabled him to penetrate the gloom by which he was surrounded, and enunciate propositions respecting the theory of heat engines, which the knowledge we now possess enables us to admit as true. his propositions are: . the motive power of heat is independent of the agents employed to develop it, and its quantity is determined solely by the temperature of the bodies between which the final transfer of caloric takes place. . the temperature of the agent must in the first instance be raised to the highest degree possible in order to obtain a great fall of caloric, and as a consequence a large production of motive power. . for the same reason the cooling of the agent must be carried to as low a degree as possible. . matters must be so arranged that the passage of the elastic agent from the higher to the lower temperature must be due to an increase of volume, that is to say, the cooling of the agent must be caused by its rarefaction. this last proposition indicates the defective information which carnot possessed. he knew that expansion of the elastic agent was accompanied by a fall of temperature, but he did not know that that fall was due to the conversion of heat into work. we should state this clause more correctly by saying that "the cooling of the agent must be caused by the external work it performs." in accordance with these propositions, it is immaterial what the heated gases or vapors in the furnace of a boiler may be, provided that they cool by doing external work and, in passing over the boiler surfaces, impart their heat energy to the water. the temperature of the furnace, it follows, must be kept as high as possible. the process of combustion is usually complex. first, in the case of coal, close to the fire-bars complete combustion of the red hot carbon takes place, and the heat so developed distills the volatile hydrocarbons and moisture in the upper layers of the fuel. the inflammable gases ignite on or near the surface of the fuel, if there be a sufficient supply of air, and burn with a bright flame for a considerable distance around the boiler. if the layer of fuel be thin, the carbonic acid formed in the first instance passes through the fuel and mixes with the other gases. if, however, the layer of fuel be thick, and the supply of air through the bars insufficient, the carbonic acid is decomposed by the red hot coke, and twice the volume of carbonic oxide is produced, and this, making its way through the fuel, burns with a pale blue flame on the surface, the result, as far as evolution of heat is concerned, being the same as if the intermediate decomposition of carbonic acid had not taken place. this property of coal has been taken advantage of by the late sir w. siemens in his gas producer, where the supply of air is purposely limited, in order that neither the hydrocarbons separated by distillation, nor the carbonic oxide formed in the thick layer of fuel, may be consumed in the producer, but remain in the form of crude gas, to be utilized in his regenerative furnaces. [illustration: the generation of steam. fig .] [illustration: the generation of steam. fig .] [illustration: the generation of steam. fig .] [illustration: the generation of steam. fig .] [illustration: the generation of steam. fig .] _(to be continued.)_ * * * * * [continued from supplement no. , page .] planetary wheel-trains. by prof. c.w. maccord, sc.d. ii. [illustration: planetary wheel trains. fig. ] it has already been shown that the rotations of all the wheels of a planetary train, relatively to the train-arm, are the same when the arm is in motion as they would be if it were fixed. now, in fig. , let a be the first and f the last wheel of an _incomplete_ train, that is, one having but one sun-wheel. as before, let these be so connected by intermediate gearing that, when t is stationary, a rotation of a through _m_ degrees shall drive f through _n_ degrees: and also as before, let t in the same time move through _a_ degrees. then, if _m'_ represent the total motion of a, we have again, m' = m + a, or m = m' - a. this is, clearly, the motion of a relatively to the fixed frame of the machine; and is measured from a fixed vertical line through the center of a. now, if we wish to express the total motion of f relatively to the same fixed frame, we must measure it from a vertical line through the center of f, wherever that maybe; which gives in this case: n' = n + a, or n = n' - a. but with respect to the train-arm when at rest, we have: ang. vel. a n ------------ = ---, whence again ang. vel. f m n' - a n ------ = --- . m' - a m this is the manner in which the equation is deduced by prof. willis, who expressly states that it applies whether the last wheel f is or is not concentric with the first wheel a, and also that the train may be composed of any combinations which transmit rotation with both a constant velocity ratio and a constant directional relation. he designates the quantities _m'_, _n'_, _absolute revolutions_, as distinguished from the _relative revolutions_ (that is, revolutions relatively to the train-arm), indicated by the quantities _m_, _n_: adding, "hence it appears that the absolute revolutions of the wheels of epicyclic trains are equal to the sum of their relative revolutions to the arm, and of the arm itself, when they take place in the same direction, and equal to the difference of these revolutions when in the opposite direction." in this deduction of the formula, as in that of prof. rankine, all the motions are supposed to have the same direction, corresponding to that of the hands of the clock; and in its application to any given train, the signs of the terms must be changed in case of any contrary motion, as explained in the preceding article. and both the deduction and the application, in reference to these incomplete trains in which the last wheel is carried by the train-arm, clearly involve and depend upon the resolving of a motion of revolution into the components of a circular translation and a rotation, in the manner previously discussed. [illustration: planetary wheel trains. fig. ] to illustrate: take the simple case of two equal wheels, fig. , of which the central one a is fixed. supposing first a for the moment released and the arm to be fixed, we see that the two wheels will turn in opposite directions with equal velocities, which gives _n_/_m_ = - ; but when a is fixed and t revolves, we have _m'_ = , whence in the general formula n' - a ------ = - , or n' = a; -a which means, being interpreted, that f makes two rotations about its axis during one revolution of t, and in the same direction. again, let a and f be equal in the -wheel train, fig. , the former being fixed as before. in this case we have: n --- = , m' = , which gives m n' - a ------- = , [therefore] n' = ; -a that is to say, the wheel f, which now evidently has a motion of circular translation, does not rotate at all about its axis during the revolution of the train-arm. [illustration: planetary wheel trains. fig. ] all this is perfectly consistent, clearly, with the hypothesis that the motion of circular translation is a simple one, and the motion of revolution about a fixed axis is a compound one. whether the hypothesis was made to substantiate the formula, or the formula constructed to suit the hypothesis, is not a matter of consequence. in either case, no difficulty will arise so long as the equation is applied only to cases in which, as in those here mentioned, that motion of revolution _can_ be resolved into those components. when the definition of an epicyclic train is restricted as it is by prof. rankine, the consideration of the hypothesis in question is entirely eliminated, and whether it be accepted or rejected, the whole matter is reduced to merely adding the motion of the train-arm to the rotation of each sun-wheel. but in attempting to apply this formula in analyzing the action of an incomplete train, we are required to add this motion of the train-arm, not only to that of a sun-wheel, but to that of a planet-wheel. this is evidently possible in the examples shown in figs. and , because the motions to be added are in all respects similar: the trains are composed of spur-wheels, and the motions, whether of revolution, translation, or rotation, _take place in parallel planes perpendicular to parallel axes_. this condition, which we have emphasized, be it observed, must hold true with regard to the motions of the first and last wheels and the train-arm, in order to make this addition possible. it is not essential that spur-wheels should be used exclusively or even at all; for instance, in fig. , a and f may be made bevel or screw-wheels, without affecting the action or the analysis; but the train-arm in all cases revolves around the central axis of the system, that is, about the axis of a, and to this the axis of f _must_ be parallel, in order to render the deduction of the formula, as made by prof. willis, and also by prof. goodeve, correct, or even possible. [illustration: planetary wheel trains. fig. ] this will be seen by an examination of fig. ; in which a and b are two equal spur-wheels, e and f two equal bevel wheels, b and e being secured to the same shaft, and a being fixed to the frame h. as the arm t goes round, b will also turn in its bearings in the same direction: let this direction be that of the clock, when the apparatus is viewed from above, then the motion of f will also have the same direction, when viewed from the central vertical axis, as shown at f': and let these directions be considered as positive. it is perfectly clear that f will turn in its bearings, in the direction indicated, at a rate precisely equal to that of the train-arm. let p be a pointer carried by f, and r a dial fixed to t; and let the pointer be vertical when oo is the plane containing the axes of a, b, and e. then, when f has gone through any angle a measured from oo, the pointer will have turned from its original vertical position through an equal angle, as shown also at f'. now, there is no conceivable sense in which the motion of t can be said to be added to the rotation of f about its axis, and the expression "absolute revolution," as applied to the motion of the last wheel in this train, is absolutely meaningless. nevertheless, prof. goodeve states (elements of mechanism, p. ) that "we may of course apply the general formula in the case of bevel wheels just as in that of spur wheels." let us try the experiment; when the train-arm is stationary, and a released and turned to the right, f turns to the left at the same rate, whence: n --- = - ; also m' = when a is fixed, m and the equation becomes n' - a ------ = - , [therefore] n' = a: - a or in other words f turns _twice_ on its axis during one revolution of t: a result too palpably absurd to require any comment. we have seen that this identical result was obtained in the case of fig. , and it would, of course, be the same were the formula applied to figs. and ; whereas it has never, so far as we are aware, been pretended that a miter or a bevel wheel will make more than one rotation about its axis in rolling once around an equal fixed one. again, if the formula be general, it should apply equally well to a train of screw wheels: let us take, for example, the single pair shown in fig. , of which, when t is fixed, the velocity ratio is unity. the directional relation, however, depends upon the direction in which the wheels are twisted: so that in applying the formula, we shall have _n/m_ = + , if the helices of both wheels are right handed, and _n_/_m_ = - , if they are both left handed. thus the formula leads to the surprising conclusion, that when a is fixed and t revolves, the planet-wheel b will revolve about its axis twice as fast as t moves, in one case, while in the other it will not revolve at all. [illustration: planetary wheel trains. fig. ] a favorite illustration of the peculiarities of epicyclic mechanism, introduced both by prof. willis and prof. goodeve, is found in the contrivance known as ferguson's mechanical paradox, shown in fig. . this consists of a fixed sun-wheel a, engaging with a planet-wheel b of the same diameter. upon the shaft of b are secured the three thin wheels e, g, i, each having teeth, and in gear with the three others f, h, k, which turn freely upon a stud fixed in the train-arm, and have respectively , , and teeth. in applying the general formula, we have the following results: n n' - a for the wheel f, --- = ---- = ---------, [therefore] n' = - ---- a. m -a n n' - a " " " h, --- = = --------, [therefore] n' = . m -a n n' - a " " " k, --- = ---- = ---------, [therefore] n' = + ---- a. m -a the paradoxical appearance, then, consists in this, that although the drivers of the three last wheels each have the same number of teeth, yet the central one, h, having a motion of circular translation, remains always parallel to itself, and relatively to it the upper one seems to turn in the same direction as the train-arm, and the lower in the contrary direction. and the appearance is accepted, too, as a reality; being explained, agreeably to the analysis just given, by saying that h has no absolute rotation about its axis, while the other wheels have; that of f being positive and that of k negative. [illustration: planetary wheel trains. fig. ] the mechanical paradox, it is clear, may be regarded as composed of three separate trains, each of which is precisely like that of fig. : and that, again, differs from the one of fig. only in the addition of a third wheel. now, we submit that the train shown in fig. is mechanically equivalent to that of fig. ; the velocity ratio and the directional relation being the same in both. and if in fig. we remove the index p, and fix upon its shaft three wheels like e, g, and i of fig. , we shall have a combination mechanically equivalent to ferguson's paradox, the three last wheels rotating in vertical planes about horizontal axes. the relative motions of those three wheels will be the same, obviously, as in fig. ; and according to the formula their absolute motions are the same, and we are invited to perceive that the central one does not rotate at all about its axis. but it _does_ rotate, nevertheless; and this unquestioned fact is of itself enough to show that there is something wrong with the formula as applied to trains like those in question. what that something is, we think, has been made clear by what precedes; since it is impossible in any sense to add together motions which are unlike, it will be seen that in order to obtain an intelligible result in cases like these, the equation must be of the form _n'_/(_m'_ - _a_) = _n_/_m_. we shall then have: n n' for the wheel f, --- = ---- = ----, [therefore] n' = - ---- a; m -a n n' for the wheel h, --- = = ----, [therefore] n' = -a; m -a n n' for the wheel k, --- = ---- = ----, [therefore] n' = - ---- a, m -a which corresponds with the actual state of things; all three wheels rotate in the same direction, the central one at the same rate as the train arm, one a little more rapidly and the third a little more slowly. it is, then, absolutely necessary to make this modification in the general formula, in order to apply it in determining the rotations of any wheel of an epicyclic train whose axis is not parallel to that of the sun-wheels. and in this modified form it applies equally well to the original arrangement of ferguson's paradox, if we abandon the artificial distinction between "absolute" and "relative" rotations of the planet-wheels, and regard a spur-wheel, like any other, as rotating on its axis when it turns in its bearings; the action of the device shown in fig. being thus explained by saying that the wheel h turns once backward during each forward revolution of the train-arm, while f turns a little more and k a little less than once, in the same direction. in this way the classification and analysis of these combinations are made more simple and consistent, and the incongruities above pointed out are avoided; since, without regard to the kind of gearing employed or the relative positions of the axes, we have the two equations: n' - a n i. -------- = ---, for all complete trains; m' - a m n' n ii. -------- = ---, for all incomplete trains. m' - a m [illustration: planetary wheel trains. fig. ] as another example of the difference in the application of these formulæ, let us take watt's sun and planet wheels, fig. . this device, as is well known, was employed by the illustrious inventor as a substitute for the crank, which some one had succeeded in patenting. it consists merely of two wheels a and f connected by the link t; a being keyed on the shaft of the engine and f being rigidly secured to the connecting-rod. suppose the rod to be of infinite length, so as to remain always parallel to itself, and the two wheels to be of equal size. then, according to prof. willis' analysis, we shall have-- n' - a n -s -------- = --- = - , n' = , [therefore] -------- = - , whence m' - a m m' - a -a = a - m', or m = a. the other view of the question is, that f turns once backward in its bearings during each forward revolution of t; whence in eq. we have-- n' n -------- = --- = - , n' = -a, m' - a m -a [therefore] -------- - , which gives -a = a - m', or m' = a, m' - a as before. it is next to be remarked, that the errors which arise from applying eq. i. to incomplete trains may in some cases counterbalance and neutralize each other, so that the final result is correct. [illustration: planetary wheel trains. fig. ] for example, take the combination shown in fig. . this consists of a train-arm t revolving about the vertical axis oo of the fixed wheel a, which is equal in diameter to f, which receives its motion by the intervention of one idle wheel carried by a stud s fixed in the arm. the second train-arm t' is fixed to the shaft of f and turns with it; a' is secured to the arm t, and f' is actuated by a' also through a single idler carried by t'. we have here a compound train, consisting of two simple planetary trains, a--f and a'--f'; and its action is to be determined by considering them separately. first suppose t' to be removed and find the motion of f; next suppose f to be removed and t fixed, and find the rotation of f'; and finally combine these results, noting that the motion of t' is the same as that of f, and the motion of a' the same as that of t. then, according to the analysis of prof. willis, we shall have (substituting the symbol _t_ for _a_ in the equation of the second train, in order to avoid confusion): n n' - a . train a--f. --- = = --------; m' = , m m' - a n' - a whence -------- = , n' = , = rot. of f. a n n' - t . train a'--f'. --- = = --------; m' = , m m' - t n' - t whence again -------- = , t = , = rot. of f'. -t of these results, the first is explicable as being the _absolute_ rotation of f, but the second is not; and it will be readily seen that the former would have been equally absurd, had the axis ll been inclined instead of vertical. but in either case we should find the errors neutralized upon combining the two, for according to the theory now under consideration, the wheel a', being fixed to t, turns once upon its axis each time that train arm revolves, and in the same direction; and the revolutions of t' equal the rotations of f, whence finally in train a'--f' we have: n n' - t . --- = = --------; in which t = , m' = a, m m' - t n' - which gives --------- = , or n' = a. a - this is, unquestionably, correct; and indeed it is quite obvious that the effect upon f' is the same, whether we say that during a revolution of t the wheel a' turns once forward and t' not at all, or adopt the other view and assert that t' turns once backward and a' not at all. but the latter view has the advantage of giving concordant results when the trains are considered separately, and that without regard to the relative positions of the axes or the kind of gearing employed. analyzing the action upon this hypothesis, we have: in train a--f: n n' n' --- = = --------; m' = , [therefore] ---- = , or n' = -a; m m' - a -a in train a'--f': n' n' n' --- = = --------; m' = , [therefore] ---- = , or n' = -t; m m' - t -t in combining, we have in the latter train m' = , t = -a, whence n n' n' --- = = -------- gives ---- = , or n' = a, as before. m m' - t +a now it happens that the only examples given by prof. willis of incomplete trains in which the axis of a planet-wheel whose motion is to be determined is not parallel to the central axis of the system, are similar to the one just discussed; the wheel in question being carried by a secondary train-arm which derives its motion from a wheel of the primary train. the application of his general equation in these cases gives results which agree with observed facts; and it would seem that this circumstance, in connection doubtless with the complexity of these compound trains, led him to the too hasty conclusion that the formula would hold true in all cases; although we are still left to wonder at his overlooking the fact that in these very cases the "absolute" and the "relative" rotations of the last wheel are identical. [illustration: planetary wheel trains. fig. ] in fig. is shown a combination consisting also of two distinct trains, in which, however, there is but one train-arm t turning freely upon the horizontal shaft oo, to which shaft the wheels a', f, are secured; the train-arm has two studs, upon which turn the idlers b b', and also carries the bearings of the last wheel f'; the first wheel a is annular, and fixed to the frame of the machine. let it be required to determine the results of one revolution of the crank h, the numbers of teeth being assigned as follows: a = , f = , a' = , f' = . we shall then have, for the train abf (eq. i.), n n' - a --- = - ---- = - = --------, in which n' = , m' = , m m' - a' - a whence - = -------, a = - a, a = , a = ---. -a and for the train a'b'f' (eq. ii.), n n' --- = ---- = = --------, in which a = ---, m' = , m m' - a' n' whence = -----------, or n' = . - ( / ) that is, the last wheel f' turns _four_ times about the axis ll during one revolution of the crank h. but according to profs. willis and goodeve, we should have for the second train: n n' - a --- = ---- = = --------, in which a = ---, m' = , m m' - a' n' - ( / ) which gives = -----------, n' - ( / ) = , n' = - / , - ( / ) or _four and one-third_ revolutions of f' for one of h. this result, no doubt, might be near enough to the truth to serve all practical purposes in the application of this mechanism to its original object, which was that of paring apples, impaled upon the fork k; but it can hardly be regarded as entirely satisfactory in a general way; nor can the analysis which renders such a result possible. * * * * * the pantanemone. the need of irrigating prairies, inundating vines, drying marshes, and accumulating electricity cheaply has, for some time past, led to a search for some means of utilizing the forces of nature better than has ever hitherto been done. wind, which figures in the first rank as a force, has thus far, with all the mills known to us, rendered services that are much inferior to those that we have a right to expect from it with improved apparatus; for the work produced, whatever the velocity of the wind, has never been greater than that that could be effected by wind of seven meters per second. but, thanks to the experiments of recent years, we are now obtaining an effective performance double that which we did with apparatus on the old system. desirous of making known the efforts that have been made in this direction, we lately described mr. dumont's atmospheric turbine. in speaking of this apparatus we stated that aerial motors generally stop or are destroyed in high winds. recently, mr. sanderson has communicated to us the result of some experiments that he has been making for years back by means of an apparatus which he styles a pantanemone. the engraving that we give of this machine shows merely a cabinet model of it; and it goes without saying that it is simply designed to exhibit the principle upon which its construction is based. [illustration: the pantanemone.] two plane surfaces in the form of semicircles are mounted at right angles to each other upon a horizontal shaft, and at an angle of ° with respect to the latter. it results from this that the apparatus will operate (even without being set) whatever be the direction of the wind, except when it blows perpendicularly upon the axle, thus permitting (owing to the impossibility of reducing the surfaces) of three-score days more work per year being obtained than can be with other mills. three distinct apparatus have been successively constructed. the first of these has been running for nine years in the vicinity of poissy, where it lifts about , liters of water to a height of meters every hours, in a wind of a velocity of from to meters per second. the second raises about , liters of water to the villejuif reservoir, at a height of meters, every hours, in a wind of from to meters. the third supplies the laboratory of the montsouris observatory. the first is not directible, the second may be directed by hand, and the third is directed automatically. these three machines defied the hurricane of the th of last january.--_la nature._ * * * * * relvas's new life-boat. the spanish and portuguese papers have recently made known some interesting experiments that have been made by mr. carlos relvas with a new life-boat which parts the waves with great facility and exhibits remarkable stability. this boat, which is shown in front view in one of the corners of our engraving, is t-shaped, and consists of a very thin keel connected with the side-timbers by iron rods. cushions of cork and canvas are adapted to the upper part, and, when the boat is on the sea, it has the appearance of an ordinary canoe, although, as may be seen, it differs essentially therefrom in the submerged part. when the sea is heavy, says mr. relvas, and the high waves are tumbling over each other, they pass over my boat, and are powerless to capsize it. my boat clears waves that others are obliged to recoil before. it has the advantage of being able to move forward, whatever be the fury of the sea, and is capable, besides, of approaching rocks without any danger of its being broken. [illustration: relvas's new life boat.] a committee was appointed by the portuguese government to examine this new life-boat, and comparative experiments were made with it and an ordinary life-boat at porto on a very rough sea. mr. relvas's boat was manned by eight rowers all provided with cork girdles, while the government life-boat was manned by twelve rowers and a pilot, all likewise wearing cork girdles. the chief of the maritime department, an engineer of the portuguese navy and a portuguese deputy were present at the trial in a pilot boat. the three boats proceeded to the entrance of the bar, where the sea was roughest, and numerous spectators collected upon the shore and wharfs followed their evolutions from afar. the experiments began at half past three o'clock in the afternoon. the two life-boats shot forward to seek the most furious waves, and were seen from afar to surmount the billows and then suddenly disappear. it was a spectacle as moving as it was curious. it was observed that mr. relvas's boat cleft the waves, while the other floated upon their surface like a nut-shell. after an hour's navigation the two boats returned to their starting point. the official committee that presided over these experiments has again found in this new boat decided advantages, and has pointed out to its inventor a few slight modifications that will render it still more efficient.--_la nature._ * * * * * experiments with double-barreled guns and rifles. the series of experiments we are about to describe has recently been made by mr. horatio phillips, a practical gun maker of london. the results will no doubt prove of interest to those concerned in the use or manufacture of firearms. the reason that the two barrels of a shot gun or rifle will, if put together parallel, throw their charges in diverging lines has never yet been satisfactorily accounted for, although many plausible and ingenious theories have been advanced for the purpose. the natural supposition would be that this divergence resulted from the axes of the barrels not being in the same vertical plane as the center line of the stock. that this is not the true explanation of the fact, the following experiment would tend to prove. [illustration: experiments with double-barrelled guns.] fig. represents a single barrel fitted with sights and firmly attached to a heavy block of beech. this was placed on an ordinary rifle rest, being fastened thereto by a pin at the corner, a, the block and barrel being free to revolve upon the pin as a center. several shots were fired both with the pin in position and with it removed, the barrel being carefully pointed at the target each time. no practical difference in the accuracy of fire was discernible under either condition. when the pin was holding the corner of the block, the recoil caused the barrel to move from right to left in a circular path; but when the pin was removed, so that the block was not attached to the rest in any way, the recoil took place in a line with the axis of the bore. it will be observed that the conditions which are present when a double barreled gun is fired in the ordinary way from the shoulder were in some respects much exaggerated in the apparatus, for the pin was a distance of in. laterally from the axis of the barrel, whereas the center of resistance of the stock of a gun against the shoulder would ordinarily be about one-sixth of this distance from the axis of the barrel. this experiment would apparently tend to prove that the recoil does not appreciably affect the path of the projectile, as it would seem that the latter must clear the muzzle before any considerable movement of the barrel takes place. with a view to obtain a further confirmation of the result of this experiment, it was repeated in a different form by a number of shots being fired from a "cross-eyed" rifle,[ ] in which the sights were fixed in the center of the rib. very accurate shooting was obtained with this arm. [footnote : a cross-eyed rifle is one made with a crooked stock for the purpose of shooting from the right shoulder, aim being taken with the left eye.] a second theory, often broached, in order to account for the divergence of the charge, is that the barrel which is not being fired, by its _vis inertia_ in some way causes the shot to diverge. in order to test this, mr. phillips took a single rifle and secured it near the muzzle to a heavy block of metal, when the accuracy of the shooting was in no way impaired. so far the experiments were of a negative character, and the next step was made with a view to discover the actual cause of the divergence referred to. a single barrel was now taken, to which a template was fitted, in order to record its exact length. the barrel was then subjected to a heavy internal hydrostatic pressure. under this treatment it expanded circumferentially and at the same time was reduced in length. this, it was considered, gave a clew to the solution of the problem. a pair of barrels was now taken and a template fitted accurately to the side of the right-hand one. as the template fitted the barrel when the latter was not subject to internal pressure, upon such pressure being applied any alterations that might ensue in the length or contour of the barrel could be duly noted. the right-hand barrel was then subjected to internal hydrostatic pressure. the result is shown in an exaggerated form in fig. . it will be seen that both barrels are bent into an arched form. this would be caused by the barrel under pressure becoming extended circumferentially, and thereby reduced in length, because the metal that is required to supply the increased circumference is taken to some extent from the length, although the substance of metal in the walls of the barrel by its expansion contributes also to the increased diameter. a simple illustration of this effect is supplied by subjecting an india-rubber tube to internal pressure. supposing the material to be sufficiently elastic and the pressure strong enough, the tube would ultimately assume a spherical form. it is a well known fact that heavy barrels with light charges give less divergence than light barrels with heavy charges. after the above experiments it was hoped that, if a pair of barrels were put together parallel and soldered only for a space of in. at the breech end, and were then coupled by two encircling rings joined together as in fig. , the left-hand ring only being soldered to the barrel, very accurate shooting would be obtained. for, it was argued, that by these means the barrel under fire would be able to contract without affecting or being affected by the other barrel; that on the right-hand, it will be seen by the illustration, was the one to slide in its ring. a pair of able . bore express rifle barrels were accordingly fitted in this way. fig. shows the arrangement with the rings in position. upon firing these barrels with ordinary express charges it was found that the lines of fire from each barrel respectively crossed each other, the bullet from the right-hand barrel striking the target in. to the left of the bull's eye, while the left barrel placed its projectile a similar distance in the opposite direction; or, as would be technically said, the barrels crossed in. at yards, the latter distance being the range at which the experiment was made. these last results have been accounted for in the following manner: the two barrels were rigidly joined for a space of in., and for that distance they would behave in a manner similar to that illustrated in fig. , and were they not coupled at the muzzles by the connecting rings they would shoot very wide, the charges taking diverging courses. when the connecting rings are fitted on, the barrel not being fired will remain practically straight, and, as it is coupled to the barrel being fired by the rings, the muzzle of the latter will be restrained from pointing outward. the result will be as shown in an exaggerated manner by the dotted lines on the right barrel in fig. . it would appear from these experiments that when very accurate shooting is required at long ranges with double-barreled rifles, they should be mounted in a manner similar to that adopted in the manufacture of the nordenfelt machine gun, in which weapon the barrels are fitted into a plate at the extreme breech end, the muzzles projecting through holes bored to receive them in a metal plate. no unequal expansion would then take place, and the barrels would be free to become shorter independently of each other. we give the above experiments on the authority of their author, who, we believe, has taken great pains to render them as exhaustive as possible, so far as they go.--_engineering._ * * * * * ball turning machine. the distinguishing feature in the ball turning machine shown opposite is that the tool is stationary, while the work revolves in two directions simultaneously. in the case of an ordinary spherical object, such as brass clack ball, the casting is made from a perfect pattern having two small caps or shanks, in which the centers are also marked to avoid centering by hand. it is fixed in the machine between two centers carried on a face plate or chuck, with which they revolve. one of these centers, when the machine is in motion, receives a continuous rotary motion about its axis from a wormwheel, d. this is driven by a worm, c, carried on a shaft at the back of the chuck, and driven itself by a wormwheel, b, which gears with a screw which rides loosely upon the mandrel, and is kept from rotating by a finger on the headstock. this center, in its rotation, carries with it the ball, which is thus slowly moved round an axis parallel to the face plate, at the same time that it revolves about the axis of the mandrel, the result being that the tool cuts upon the ball a scroll, of which each convolution is approximately a circle, and lies in a plane parallel to the line of centers. when the chuck is set for one size of ball, which may be done in a few minutes, any quantity of that diameter may be turned without further adjustment. a roughing cut for a in. ball may be done in one minute, and a finishing cut leaving the ball quite bright in the same time. the two paps are cut off within one-sixteenth of an inch and then broken off, and the ball finished in the usual way. on account of the work being geometrically true, the finishing by the ferrule tool is done in one quarter of the time usually required. [illustration: improved ball turning machine.] the chuck may be applied to an ordinary lathe or may be combined with a special machine tool, as show in our illustration. in the latter case everything is arranged in the most handy way for rapid working, and six brass balls of in. in diameter can be turned and finished in an hour. the machine is specially adapted for turning ball valves for pumps, pulsometers, and the like, and in the larger sizes for turning governor balls and spherical nuts for armor plates, and is manufactured by messrs. wilkinson and lister, of bradford road iron works, keighley.--_engineering._ * * * * * cooling apparatus for injection water. it often happens in towns and where manufactories are crowded together, that the supply of water for condensing purposes is very small, and consequently that it attains an inconveniently high temperature under unfavorable conditions of weather, resulting in the deterioration of the vacuum and a consequent increase in the consumption of fuel. to remedy or to diminish this difficulty, messrs. boase and miller, of london, have brought out the water cooler illustrated above. this consists, says _engineering_, of a revolving basket of wire gauze surrounding an inner stationary vessel pierced with numerous small holes, through which the heated water discharged by the air pump finds its way into the basket, to be thrown out in the form of fine spray to a distance of ft. at each side. the drops are received in the tank or pond, and in their rapid passage through the air are sufficiently cooled to be again injected into the condenser. the illustration shows a cooler having a basket three feet in diameter, revolving at revolutions per minute, and discharging into a tank ft. square. it requires to indicated horse-power to drive it, and will cool gallons per minute. the following decrease of temperature has been observed in actual practice: water entering at deg. fell deg. in temperature; water entering at deg. to deg. fell deg.; and water entering at deg. to deg. fell deg. the machine with which these trials were made was so placed that the top of the basket was four ft. from the surface of the water in the pond. with a greater elevation, as shown in the engraving, better results can be obtained. [illustration: improved water cooling apparatus.] the advantages claimed for the cooler are that by its means the temperature of the injection water can be reduced, the cost and size of cooling ponds can be diminished, and condensing engines can be employed where hitherto they have not been possible. the apparatus has been for two years in operation at several large factories, and there is every reason to believe that its use will extend, as it supplies a real want in a very simple and ingenious manner. messrs. duncan brothers, of dundee and queen victoria street, e.c., are the manufacturers. * * * * * corrugated disk pulleys. this is a pulley recently introduced by messrs. j. and e. hall, of dartford eng. with the exception of the boss, which is cast, it is composed entirely of steel or sheet iron. in place of the usual arms a continuous web of corrugated sheet metal connects the boss to the rim; this web is attached to the boss by means of spence's metal. inside the rim, which is flanged inward, a double hoop iron ring is fixed for strengthening purposes. the advantageous disposition of metal obtained by means of the corrugated web enables the pulley to be made of a given strength with less weight of material, and from this cause and also on account of being accurately balanced these pulleys are well adapted for high speeds. [illustration] * * * * * [kansas city review.] early history of the telegraph. although the electric telegraph is, comparatively speaking, a recent invention, yet methods of communication at a distance, by means of signals, have probably existed in all ages and in all nations. there is reason to believe that among the greeks a system of telegraphy was in use, as the burning of troy was certainly known in greece very soon after it happened, and before any person had returned from troy. polybius names the different instruments used by the ancients for communicating information--"pyrsia," because the signals were always made by means of fire lights. at first they communicated information of events in an imperfect manner, but a new method was invented by cleoxenus, which was much improved by polybius, as he himself informs us, and which may be described as follows: take the letters of the alphabet and arrange them on a board in five columns, each column containing five letters; then the man who signals would hold up with his left hand a number of torches which would represent the number of the column from which the letter is to be taken, and with his right hand a number of torches that will represent the particular letter in that column that is to be taken. it is thus easy to understand how the letters of a short sentence are communicated from station to station as far as required. this is the pyrsia or telegraph of polybius. it seems that the romans had a method of telegraphing in their walled cities, either by a hollow formed in the masonry, or by a tube fixed thereto so as to confine the sound, in order to convey information to any part they liked. this method of communicating is in the present age frequently employed in the well known speaking tubes. it does not appear that the moderns had thought of such a thing as a telegraph until , when the marquis of worcester, in his "century of inventions," affirmed that he had discovered a method by which a man could hold discourse with his correspondent as far as they could reach, by night as well as by day; he did not, however, describe this invention. dr. hooke delivered a discourse before the royal society in , showing how to communicate at great distances. in this discourse he asserts the possibility of conveying intelligence from one place to another at a distance of miles as rapidly as a man can write what he would have sent. he takes to his aid the then recent invention of the telescope, and explains how characters exposed at one station on the top of one hill may be made visible to the next station on the top of the next hill. he invented twenty-four simple characters, each formed of a combination of three deal boards, each character representing a letter by the use of cords; these characters were pushed from behind a screen and exposed, and then withdrawn behind the screen again. it was not, however, until the french revolution that the telegraph was applied to practical purposes; but about the end of telegraphic communication was established between paris and the frontiers, and shortly afterward telegraphs were introduced into england. the history of the invention and introduction of the electric telegraph by prof. morse is one of inexhaustible interest, and every incident relating to it is worthy of preservation. the incidents described below will be found of special interest. the article is from the pen of the late judge neilson poe, and was the last paper written by him. he prepared it during his recent illness, the letter embodied in it from mr. latrobe being of course obtained at the time of its date. it is as follows: on the th of april, , when the monthly meeting of the directors of the baltimore & ohio railroad company was about to adjourn, the president, the hon. louis mclane, rose with a paper in his hand which he said he had almost overlooked, and which the secretary would read. it proved to be an application from prof. morse for the privilege of laying the wires of his electric telegraph along the line of the railroad between baltimore and washington, and was accompanied by a communication from b.h. latrobe, esq., chief engineer, recommending the project as worthy of encouragement. on motion of john spear nicholas, seconded by the hon. john p. kennedy, the following resolution was then considered: _resolved_, "that the president be authorized to afford mr. morse such facilities as may be requisite to give his invention a proper trial upon the washington road, provided in his opinion and in that of the engineer it can be done without injury to the road and without embarrassment to the operations of the company, and provided mr. morse will concede to the company the use of the telegraph upon the road without expense, and reserving to the company the right of discontinuing the use if, _upon experiment_, it should prove _in any manner injurious_." "whatever," said mr. mclane, "may be our individual opinions as to the feasibility of mr. morse's invention, it seems to me that it is our duty to concede to him the privilege he asks, and to lend him all the aid in our power, especially as the resolution carefully protects the company against all present or future injury to its works, and secures us the right of requiring its removal at any time." [in view of the fact that no railroad can now be run safely without the aid of the telegraph, the cautious care with which the right to remove it if it should become a nuisance was reserved, strikes one at this day as nearly ludicrous.] a short pause ensued, and the assent of the company was about to be assumed, when one of the older directors, famed for the vigilance with which he watched even the most trivial measure, begged to be heard. he admitted that the rights and interests of the work were all carefully guarded by the terms of the resolution, and that the company was not called upon to lay out any of its means for the promotion of the scheme. but notwithstanding all this, he did not feel, as a conscientious man, that he could, without further examination, give his vote for the resolution. he knew that this idea of mr. morse, however plausible it might appear to theorists and dreamers, and so-called men of science, was regarded by all practical people as destined, like many other similar projects, to certain failure, and must consequently result in loss and possibly ruin to mr. morse. for one, he felt conscientiously scrupulous in giving a vote which would aid or tempt a visionary enthusiast to ruin himself. fortunately, the views of this cautious, practical man did not prevail. a few words from the mover of the resolution, mr. nicholas, who still lives to behold the wonders he helped to create, and from mr. kennedy, without whose aid the appropriation would not have passed the house of representatives, relieved the other directors from all fear of contributing to mr. morse's ruin, and the resolution was adopted. of the president and thirty directors who took part in this transaction, only three, samuel w. smith, john spear nicholas, and the writer, survive. under it morse at once entered upon that test of his invention whose fruits are now enjoyed by the people of all the continents. it was not, however, until the spring of that he had his line and its appointments in such a condition as to allow the transmission of messages between the two cities, and it was in may of that year that the incident occurred which has chiefly led to the writing of this paper. mr. latrobe's recollections. my dear mr. poe: agreeably to my promise, this morning i put on paper my recollection of the introduction of the magnetic telegraph between baltimore and washington. i was counsel of the baltimore & ohio railroad co. at the time, and calling on mr. louis mclane, the president, on some professional matter, was asked in the course of conversation whether i knew anything about an electric telegraph which the inventor, who had obtained an appropriation from congress, wanted to lay down on the washington branch of the road. he said he expected mr. morse, the inventor, to call on him, when he would introduce me to him, and would be glad if i took an opportunity to go over the subject with him and afterward let him, mr. mclane, know what i thought about it. while we were yet speaking, mr. morse made his appearance, and when mr. mclane introduced me he referred to the fact that, as i had been educated at west point, i might the more readily understand the scientific bearings of mr. morse's invention. the president's office being no place for prolonged conversation, it was agreed that mr. morse should take tea at my dwelling, when we would go over the whole subject. we met accordingly, and it was late in the night before we parted. mr. morse went over the history of his invention from the beginning with an interest and enthusiasm that had survived the wearying toil of an application to congress, and with the aid of diagrams drawn on the instant made me master of the matter, and wrote for me the telegraphic alphabet which is still in use over the world. not a small part of what mr. morse said on this occasion had reference to the future of his invention, its influence upon communities and individuals, and i remember regarding as the wild speculations of an active imagination what he prophesied in this connection, and which i have lived to see even more than realized. nor was his conversation confined to his invention. a distinguished artist, an educated gentleman, an observant traveler, it was delightful to hear him talk, and at this late day i recall few more pleasant evenings than the only one i passed in his company. of course, my first visit the next morning was to mr. mclane to make my report. by this time i had become almost as enthusiastic as mr. morse himself, and repeated what had passed between us. i soon saw that mr. mclane was becoming as eager for the construction of the line to washington as mr. morse could desire. he entered warmly into the spirit of the thing, and laughed heartily, if not incredulously, when i told him that although he had been minister to england, secretary of state, and secretary of the treasury, his name would be forgotten, while that of morse would never cease to be remembered with gratitude and praise. we then considered the question as to the right of the company to permit the line to be laid in the bed of the road--the plan of construction at that time being to bury in a trench some eight or ten inches deep a half inch leaden tube containing the wrapped wire that was to form the electric circuit. about this there was, in my opinion, no doubt, and it was not long after that the work of construction commenced. i met mr. morse from time to time while he lived, and often recurred to the evening's discussion at my house in baltimore. the above is the substance of what i have more than once related to other persons. i hope you will persist in your design of putting on paper your own very interesting recollections in this connection, and if what i have contributed of mine is of service to you, i shall be much pleased. most truly yours, john h.b. latrobe. march , . * * * * * the kravogl electric motor. at the origin of every science, of whatever nature it may be, there is always a fruitless period, of greater or less length, characterized by the warfare of a few superior minds against general apathy. the finest discoveries pass unperceived, so to speak, since they cannot cross the limits of a narrow circle; and it often happens that they fall into oblivion before they have been seriously judged. meanwhile, a slow progress is imperceptibly made, and, in measure as theoretical principles more clearly disengage themselves, a few industrial applications spring up and have the effect of awakening curiosity. an impulse is thus given, and from this moment a movement in advance goes on increasing at a headlong pace from day to day. with electricity this period has been of comparatively short duration, since scarcely a century and a half separate us from the first experiments made in this line of research. now that it has truly taken its place in a rank with the other sciences, we like to go back to the hesitations of the first hour, and trace, step by step, the history of the progress made, so as to assign to each one that portion of the merit that belongs to him in the common work. when we thus cast a retrospective glance we find ourselves in the presence of one strange fact, and that is the simultaneousness of discoveries. that an absolutely original idea, fertile in practical consequences, should rise at a given moment in a fine brain is well; we admire the discovery, and, in spite of us, a little surprise mingles with our admiration. but is it not a truly curious thing that _several_ individuals should have had at nearly the same time that idea that was so astonishing in one? this, however, is a fact that the history of electrical inventions offers more than one example of. no one ignores the fact that the invention of the telephone gave rise to a notorious lawsuit, two inventors having had this ingenious apparatus patented on the same day and at nearly the same hour. this is one example among a thousand. in the history of dynamo-electric machines it is an equally delicate matter to fix upon the one to whom belongs the honor of having first clearly conceived the possibility of engendering continuous currents. we do not wish to take up this debate nor to go over the history of the question again. every one knows that the first continuous current electric generator whose form was practical is due to zenobius gramme, and dates back to july, , an epoch at which appeared a memoir (entitled "note upon a magneto-electric machine that produces continuous currents") that was read to the academy of sciences by mr. jamin. ten years previous, pacinotti had had a glimpse of the phenomenon, and of its practical realization, but was unfortunately unable to appreciate the importance of his discovery and the benefit that might be reaped from it. it is of slight consequence whether gramme knew of this experiment or not, for the glory that attaches to his name could not be diminished for all that. but an interesting fact that we propose to dwell upon now has recently been brought to light in an electrical review published at vienna.[ ] it results from documents whose authenticity cannot be doubted that, as far back as , mr. l. pfaundler, a professor at innsbruck, very clearly announced the reversibility of a magneto-electric motor constructed by kravogl, a mechanician of the same place, and that he succeeded some time before gramme in obtaining continuous currents. [footnote : _zeitschrift des electrotechnischen vereines_ in _wien_, july, .] the kravogl motor that figured at the universal exhibition of is but little known, and it is now very difficult to obtain drawings of it. what is certain is that this motor is an application of the properties of the solenoid, and, from this standpoint, resembles the bessolo motor that was patented in . we may figure the apparatus to our mind very well if we suppose that in the gramme ring a half and almost two-thirds of the core are removed, and the spirals are movable around the said core. if a current be sent into a portion of the spirals only, and in such a way that only half of the core be exposed, the latter will move with respect to the bobbin or the bobbin with respect to the core, according as we suppose the solenoid or the bobbin fixed. in the first case we have a bessolo motor, and in the second a kravogl one. in order to obtain a continuous motion it is only necessary to allow the current to circulate successively in the different portions of the solenoid. it is difficult to keep the core in place, since it is unreachable, being placed in the interior of the bobbin. kravogl solved this difficulty by constructing a hollow core into which he poured melted lead. this heavy piece, mounted upon rollers, assumed a position of equilibrium that resulted from its weight, from friction, and from magnetic attraction. but for a current of given intensity this position, once reached, did not vary, and so necessitated a simple adjustment of the rubbers. under such circumstances, with a somewhat large number of sections, the polarity of the core was nearly constant. the spirals as a whole were attached to a soft iron armature that had the effect of closing up the lines of forces and forming a shell, so to speak. like bessolo, kravogl never thought of making anything but a motor, and did not perceive that his machine was reversible. it results from some correspondence between dr. a. von waltenhofen and mr. l. pfaundler at this epoch that the latter clearly saw the possibility of utilizing this motor as a current generator. under date of november , , he wrote, in speaking of the kravogl motor, which had just been taken to innsbruck in order to send it to paris. "i regret that i shall not be able to see it any more, for i should have liked to try to make it act in an opposite direction, that is to say, to produce a current or an electric light by means of mechanical work." a little more than two years later these experiments were carried out on a larger motor constructed by kravogl in , and mr. pfaundler was enabled to write as follows: "upon running the machine by hand we obtain a current whose energy is that of one bunsen element." this letter is dated february , , that is to say, it is a year anterior to the note of gramme. [illustration: fig. .] in the presence of the historic interest that attaches to the question, we do not think it will be out of place to reproduce here the considerations that guided prof. pfaundler in the researches that led him to convert the kravogl motor into a dynamo-electric machine. let us consider two magnetized bars, _db_ and _bd'_, placed end to end and surrounded by a cylindrical armature forming a shell, this armature being likewise supposed to be a permanent magnet and to present poles of contrary direction opposite the poles of the bars. for the sake of greater simplicity this shell is represented by a part only in the figure, _s n n s_. if, into a magnetic field thus formed, we pass a spiral from left to right, the spiral will be traversed by a current whose direction will change according to the way in which the moving is done. it is only necessary to apply lenz's law to see that a reversal of the currents will occur at the points, _a_ and _c_, the direction of the current being represented by arrows in the figure. if we suppose a continual displacement of the spirals from left to right, we shall collect a continuous current by placing two rubbers at _a_ and _c_. either the core or the shell may be replaced by a piece of soft iron. in such a case this piece will move with the spiral and keep its poles that are developed by induction fixed in space. from this, in order to reach a dynamo-electric machine it is necessary to try to develop the energy of the magnetic field by the action of the current itself. if we suppose the core to be of soft iron, and make a closer study of the action of the current as regards the polarity that occurs under the influence of the poles, _s_, _n_, _s_, we shall see that from _d_ to _a_ and from _b_ to _c_ the current is contrary, while that from _a_ to _b_ and from _c_ to _d'_ it is favorable to the development of such polarity. in short, with a spiral moving from _d_ to _d'_ the resulting effect is _nil_, a fact, moreover, that is self-evident. under such circumstances, if we suppose the shell, as well as the core, to be of soft iron, we shall obtain a feeble current due to the presence of remanent magnetism; but this magnetism will not be able to continue increasing under the influence of the current. to solve this difficulty two means present themselves: ( ) to cause a, favorable magnetic current and act upon the armature, and ( ) to suppress such portions of the current in the spirals as are injurious in effect. the first solution was thought of by gramme in , and is represented diagramatically in fig. . the second is due to prof. pfaundler, and dates back to . the core is cut through the center (fig. ), and the portion to the right is suppressed; the current is interrupted between _da_ and _cd'_, and is closed only between _a_ and _c_ (_v_, fig. ). it results from this arrangement that, under the action of the current, the polarity due to remanent magnetism does nothing but increase. it suffices then for but little remanent magnetism to prime the machine; the polarity of the shell continues to increase, and the energy of the magnetic field, and consequently of the current, has for a limit only the saturation of the soft iron. if, now, we curve the core, the spirals, and the armature into a circle, we have a gramme or a pfaundler machine, according as we consider fig. or fig. . [illustration: fig. .] [illustration: fig. .] this latter apparatus has in this case the form shown in fig. . [illustration: fig. .] the spiral, _s m b_, is movable, and the core, n _o s_, is kept in a position of equilibrium by virtue of its weight, and is provided with rollers. for the sake of greater clearness, the front part of the armature is supposed to be removed. the current does not circulate in the spirals to the right of the diameter, w o, which latter is not absolutely vertical. the position of the rubbers and armature is regulated once for all. we do not know just what were the means devised by kravogl to suppress the current in the spheres to the right. at all events, it is probable that the system has grown old since gramme invented his collector. in the application of the kravogl motor to the generation of continuous currents, professor pfaundler now proposes to ingeniously utilize the gramme collector. in such a case the arrangement shown in fig. would be adopted. let us suppose an ordinary collector having as many plates as there are sections in the ring, these plates being connected as usual with the entrance and exit wires of the sections. the diametrically opposite touches that are in the line, w o, are divided, and one of the halves is connected at the entrance, _c a'_ (fig. ), with the corresponding section, while the other communicates with the exit, _c' a_, of the neighboring section. each of these halves is prolonged by a piece of metal bent into the form of an arc of a circle and embracing a little less than a semi-circumference. between these prolongations there is an insulating part. in the rotary motion of the spiral, at least one of the touches is always outside of the arc comprised between the brushes, r. in order to secure a continuity of the circuit in the effective arc, w s_ o_, it is only necessary to arrange a rubber, m, in such a way as to establish a communication between the two parts of the divided touch as soon as this latter enters the arc under consideration. in order to produce a current in the direction of the arrows shown in fig. , the spiral and axle must revolve from right to left. in this case the rubber, m, occupies the position shown in the same figure, the brushes embracing an arc of a little less than °. as soon as the lower touch comes in contact with the brush, r, when the revolution is being effected from left to right, the rubber, m, establishes a communication between the two halves that have until now been isolated, and the current is no longer interrupted. the second touch during this time is at any point whatever of the arc, w n _o_, and the spirals corresponding to the latter arc outside of the circuit. in short, thanks to the rubber, m, we have an ordinary gramme collector in that portion of the circuit comprised between the brushes, and a collector with a breakage of the circuit in the portion to the right. [illustration: fig. .] this type of machine is entirely theoretical. in the apparatus used for prof. pfaundler's experiments in , the armature revolved with the solenoid. the core and armature were of soft iron, and the core was arranged in a manner analogous to the preceding, and remained in place under the action of its weight, and the shell, forming a complete circle, revolved with poles fixed in space. practically, the machine that we have just described would prove inconvenient to realize, and would present serious inconveniences. in the first place, it seems to us quite difficult to transmit the motion of the solenoid to the axle, supposing the former to revolve within the armature. in the second place, considerable friction would surely occur between the spirals and core, and the axle, being submitted to a lateral stress, would be placed in a poor condition for work. it is even allowable to doubt whether such a type could be practically got up. at all events, no trial has as yet been made of it. compared with the gramme machine, from an absolutely theoretical point of view, the pfaundler apparatus presents undoubted advantages. a theoretically perfect dynamo electric machine would be one in which there was a complete reciprocity between the magnetizing action of the current and the inductive action of the magnetic field. now, such is not the case in the gramme machine. in this apparatus the soft iron core is at the same time a magnet through favorable induction and a disadvantageous electro-magnet. this double polarization is only remedied to a certain extent by the adjustment of the brushes. in the pfaundler machine, on the contrary, the electro-magnetism and magnetism through induction act in the same direction, and concur in effecting a polarization that favors the production of the current. looked at it in this light, the latter machine more nearly approaches the type of perfection than does that of gramme. but we must not forget that such qualities are purely theoretical. in practice the best machine is that in which the copper is best utilized, that is to say, that which with a given weight of this metal furnishes the most work. now, this is certainly not the case in the pfaundler machine, for here half or more than half of the ring is inert--a defect which is apparent at first sight. it results from this that as soon as we propose to obtain an electromotive force, however slight it be, we must get it with machines of large dimensions. now, it is permissible to believe that under such circumstances (taking into consideration the complication of mechanical means that the construction of such apparatus necessitates, and the great friction that occurs) it would be impossible to obtain practical rotary velocities. comparing his machine with gramme's, prof. pfaundler expresses the idea that between them there is the same analogy as there is between a constant pressure and an expansion engine. with cylinders of equal diameters the work performed by the former of these is greater than that done by the second, but in the latter the expansive force of the steam is better utilized. this comparison seems to us to be more ingenious than exact. would it not be coming nearer to the truth if we were to suppose a case of a hydraulic motor whose performance continued diminishing with the height of the fall, and would it not be advantageous under such circumstances to utilize only a portion of the fall for the purpose of increasing the motor's performance? this machine, however, as before stated, has never as yet been constructed, so that experimental data relative to its mode of working are wanting. it is especially interesting as regards its origin, which dates back to an epoch at which researches on the dynamo electric machine were at their heat. it is in its historical aspect that it is proper to regard it, and it is from such a point of view that we have deemed it well to say a few words about it in this place.--_la lumiere electrique._ * * * * * bornhardt's electric machine for blasting in mines. we shall not attempt to pass in review the several apparatus that have hitherto been devised for igniting blasts in mining operations, but shall simply describe in this place a machine recently invented for this purpose by mr. bornhardt, an engineer to the grand duke of brunswick. this apparatus (shown in the accompanying engravings) consists essentially of two hard-rubber disks, a (figs. and ), keyed to an iron axle, and of two rubbers, b, that are formed of skin and are held against the disks by small springs, r; motion is communicated to the axle, _a_, by means of a pair of gearings, _a_ and _b_, and a crank, _f_. [illustration: bornhardt's electric machine for blasting in mines.] each disk revolves between two metallic rings, _c_, provided with points that attract and collect in leyden jars, d, the electricity produced by the friction. for discharging the condensers there is employed a manipulator formed of a rod, mm, which can be acted upon, from the exterior, by means of a button, _k_. upon bringing the ball, _m_, of the rod in contact with the ball, _p_, of the condenser, the lever (which then takes the position shown by the dotted line) continues to remain in connection with a small ring, _q_, through a special spring. another ring, _t_, is connected in the same way with the external armature of the condenser. upon connecting the rings, _p_ and _t_, by a wire to which cartridges are attached, any number of the latter may be ignited. the parts that we have just enumerated are inclosed in a tin box covered with a wooden casing, p. between the two there is inserted a sheet of hard rubber in order to prevent a loss of electricity; the whole is held in place by strong springs. in order to show the normal state of the condenser, a scale consisting of metallic buttons to give the dimensions of the sparks, is arranged at x. this scale is capable of being connected with the rings, _q_ and _t_, by means of chains; when the spark obtained after or revolutions considerably exceeds the intervals of the scale, it is a sure thing that the machine is in a proper state. in order to prepare the apparatus for carriage, the winch is taken off and placed in the compartment, _m_, which is closed by means of a door, q. figs. and show the arrangement of the dynamite cartridges and wires in the blast hole. figs. to show different arrangements of the igniting wires. figs. and give the general arrangement for igniting a number of cartridges simultaneously by means of the electric machine. fig. shows the arrangement where powder is employed. fig. shows the arrangement of a horizontal hole.--_annales industrielles._ * * * * * improved electric fire alarm. the object of this apparatus is to close an electric circuit when the temperature of a room rises above a certain point. many devices have been invented for effecting this object, each of which have their own advantages or disadvantages. the invention of mr. pritchett enables the required result to be obtained in a very satisfactory manner. the apparatus consists (as shown by the figure) of a long glass vessel containing air; connected to this vessel there is a glass tube filled with mercury. the whole is mounted on a metal cradle, which turns on pivots. according to the position which the glass vessel and its adjuncts occupy in the cradle (this position being adjustable by means of a thumb-screw, seen at the upper part of the cradle), so will the same have a tendency to rock longitudinally over to one side or the other. now, if we suppose the position to be such that the right hand end of the glass vessel is depressed, and the left hand end raised, then if the vessel becomes subjected to an elevation of temperature, the air inside the same will become expanded, and the mercury column in the tube will be driven over to the left, and will rise in the turned up end of the tube. this will cause the left hand branch of the glass vessel, and its attachments, to become increased in weight, while the right hand branch will become proportionally lighter; the consequence of this will be that the vessel and its cradle will cant over, and by falling on an electrical contact will close a circuit and sound an alarm. it is obvious that the apparatus is equally well adapted for indicating a diminution as well as an increase of temperature, for if the electrical contact be placed under the right hand portion of the cradle, and the latter be adjusted so that in its normal position its left hand portion is depressed, then when the glass vessel becomes cooled, the air in it will contract, and the mercury will fall in the turned-up portion of the tube before referred to, and will rise in the limb connected to the vessel, consequently the cradle and glass vessel will cant over in the reverse way to that which it did in the first case. owing to the surface which the glass vessel exposes, the air inside quickly responds to any external change of temperature, consequently the apparatus is very sensitive. another important feature is the fact that the cradle and vessel in canting over acquires a certain momentum, and thus the contact made becomes very certain. [illustration: pritchett's electric fire alarm.] mr. pritchett proposes that his apparatus shall give external evidence outside the house by ringing a gong, and by dropping a semaphore arm released by an electromagnet. he also proposes (as has often been suggested) that a water supply shall be automatically turned on.--_electrical review._ * * * * * a standard thermopile. dr. g. gore, f.r.s., has invented an improved thermopile for measuring small electromotive forces. it consists of about pairs of horizontal, slender, parallel wires of iron and german silver, the former being covered with cotton. they are mounted on a wooden frame. about ½ in. of the opposite ends of the wires are bent downward to a vertical position to enable them to dip into liquids at different temperatures contained in long narrow troughs; the liquids being non-conductors, such as melted paraffin for the hot junctions, and the non-volatile petroleum, known as thin machinery oil. the electromotive force obtained varies with the temperature; a pile of pairs having a resistance of . ohms at deg. cent. gave with a difference of temperature of deg. cent. an electromotive force of . volts, or with deg. cent. an electromotive force of . volt. each element, therefore, equaled . volt for each degree cent. difference of temperature. on having been verified with a standard voltaic cell the apparatus becomes itself a standard, especially for small electromotive forces. it is capable of measuring the / part of a volt. for higher electromotive forces than a volt, several of these piles would have to be connected in series. the fractional electromotive force is obtained by means of a sliding contact which cuts out so many pairs as is required. * * * * * telephonic transmission without receivers. the annual meeting of the french society of physics, the success of which is continually increasing, took place this year in the salons of the observatory, which were kindly placed at the society's disposal by admiral mouchez. there were three consecutive sessions, the one of tuesday, april , being set apart for the members of the association, the one of the th for the invited guests of admiral mouchez, and that of the th for the invited guests of the society. the salons were partially lighted by the siemens differential arc, continuous current lamps, and partially by the swan incandescent lamp supplied by a distributing machine that permitted of the lamps being lighted and extinguished at will without changing the normal operation of all the rest. many apparatus figured at this exhibition, but we shall on the present occasion merely call attention to those that presented a certain character of novelty or of originality. among the apparatus that we shall reserve a description of for the present was messrs. richard bros.' registering thermometer designed for the concarneau laboratory, an instrument which, when sunk at one mile from the coast, and to a depth of meters, will give a diagram of the temperature of the ocean at that depth; and mr. hospitalier's continuous electrical indicators, designed for making known from a distance such mechanical or physical phenomena as velocities, levels, temperatures, pressures, etc. among the most important of the apparatus exhibited we must reckon mr. cailletet's devices for liquefying gases, and those of mr. mascart for determining the ohm. the results obtained by mr. mascart (which have been submitted to the committee on unities of the congress of electricians now in session at paris), are sensibly concordant with those obtained independently in england by lord rayleigh. everything leads to the hope, then, that a rapid and definite solution will be given of this important question of electric unities, and that nothing further will prevent the international development of the c.g.s. system. mr. jules duboscq made a number of very successful projections, and we particularly remarked the peculiar experiment made in conjunction with mr. parinaud, that gave in projection two like spectra produced by the same prism, and which, through superposition, were capable of increasing the intensity of the colors, or, on the contrary, of reconstituting white light. among the optical applications we may cite mr. leon laurent's apparatus for controlling plane, parallel, perpendicular, and oblique surfaces, and magic mirrors obtained with an ordinary light; mr. s.p. thompson's apparatus for demonstrating the propagation of electro-magnetic waves in ether (according to maxwell's theory), as well as some new polarizing prisms; and a mode of lighting the microscope (presented by mr. yvon), that was quite analogous to the one employed more than a year ago by dr. van heurck, director of the botanical garden of anvers. acoustics were represented by an electro-magnetic brake siren of mr. bourbouze; konig's apparatus for the synthesis of sounds; and mr. s.p. thompson's cymatograph--a pendulum apparatus for demonstrating the phenomena of beats. it was electricity again that occupied the largest space in the programme of the session. apparatus for teaching are assuming greater and greater importance every day, and the exhibit of mr. ducretet included a large number of the most interesting of these. the house of breguet exhibited on a reduced scale the magnificent experiments of gaston plante, wherein leaden wire secondary elements charged for quantity with daniell elements, and afterward coupled for tension, served to charge a rheostatic machine formed of condensers coupled for quantity. these latter, coupled anew for tension, furnished upon being discharged a spark due to a difference of potential of about , volts that presented all the characters of the spark produced by induction coils on the machines so improperly called "static." finally, we may cite the apparatus arranged by mr. s.p. thompson for studying the development of currents in magneto-electric machines. the inventor studies the influence of the forms of the inductors and armatures of machines by means of an arrangement that allows him to change the rings or armatures at will and to take out the induced bobbins in order to sound every part of the magnetic field. upon giving the armature an angular motion limited by two stops, there develops a certain quantity of electricity that may be measured by causing it to traverse an appropriate ballistic galvanometer. messrs. deprez and d'arsonval's galvanometer answers very well for this purpose, and its aperiodicity, which causes it quickly to return to zero as soon as the induced current ceases, permits of a large number of readings being taken within a very short space of time. measuring apparatus were represented by a new and very elegant arrangement of sir william thomson's reflecting galvanometers, due to mr. j. carpentier. the mounting adopted by mr. carpentier permits of an easy removal of the bobbins and of an instantaneous substitution therefor. the galvanometric part, composed of the needles and mirror, therefore remains entirely free, thus allowing of its being verified, and making it convenient to attach the silken fiber. mr. carpentier has, moreover, adopted for all the minor apparatus a transparent celluloid scale which simplifies them, facilitates observations, and renders the use of reflection almost industrial. we shall complete our enumeration of the measuring apparatus by citing ducretet's non-oscillating galvanometer, sir william thomson's amperemeters, voltameters, ohmmeters, and mhosmeters, constructed and exhibited by breguet, and a new aperiodic galvanoscope of mr. maiche. mr. baudot exhibited the recent improvements that he has made in his multiplex printing telegraph, and m. boudet of paris showed a new system of telephone transmission by submarine cables. [illustration: fig. .--diagram exhibiting the arrangement for telephonic transmissions without a receiver.] finally, we shall conclude our enumeration by referring to the curiosities. the house of siemens exhibited a miniature electric railway actuated by a new model of reynier accumulators; m. maiche operated a system of musical telephonic auditions that differed only in detail from those instituted by mr. ader at the exhibition of ; and mr. hospitalier presented a new form of an experiment devised by mr. giltay, consisting of a telephonic transmission of sounds without the use of receivers. mr. giltay's experiment is nothing but mr. dunand's speaking condenser without the condenser. a glance at fig. will show how things are arranged for the experiment. the transmitting system comprises two distinct circuits, viz.: ( ) one formed of a pile, p, of or leclanche elements, or of or small sized accumulators, an ader microphane transmitter, m, and the inducting wire of a small induction coil, b; and ( ) the other formed of the induced wire of the coil, b, of a pile, p', of or leclanche elements, and of a line whose extremities terminate at r, in two ordinary electro-medical handles. with this arrangement the experiment performed is as follows: when any one speaks or sings in front of the transmitter, t, while two persons, a and b, each having one hand gloved, are holding the handles in the ungloved hand, it is only necessary for a to place his gloved hand upon b's ear, or for the latter to place his hand upon a's, or for each to place his hand on the other's ear simultaneously, in order that a or b, or a and b simultaneously, may hear a voice issuing from the glove. under these circumstances, mr. giltay's experiment is explained like dunand's speaking condenser--the hand of a and the ear of b here constituting the armature of an elementary condenser in which the glove performs the role of dielectric. upon repeating this experiment at the laboratory of the school of physics and industrial chemistry of paris, it has been found that the glove maybe replaced by a sheet of plain or paraffined paper. in this case, when two persons are holding the handles, and have their ears applied, one against the other, if a sheet of paper be interposed, airs or words will be heard to proceed therefrom. finally, it has been found possible to entirely suppress the paper, or dielectric, and to hear directly, by simply interposing the auditor or auditors in the circuit. one of the most curious forms of the experiment is the one shown in fig. . here a third person, c, hears the hands of a and b speak when a circuit is formed by means of three persons, a, b, and c, the two former, a and b, each holding one of the wires of the circuit and applying his free hand to the ear of c. although the experiment is one that requires entire silence, and could not on that account be performed at the laboratory, a sort of telephonic chain can be formed in which five or six persons may hear at the same time. a, putting his hand on the ear of b, the latter putting his to that of c, and so on up to the last person, who closes the circuit by grasping one of the handles, the other one being held by a. [illustration: experiment on telephonic transmission without receiving apparatus.] it is difficult in the present state of science to explain very clearly how these telephonic transmissions are effected without a receiver. all that we can conclude from it so far is that the ear is an instrument of incomparable delicacy and of exquisite sensitiveness, since it perceives vibrations in which the energy developer, particularly in the telephonic chain, is exceedingly feeble. without any desire to seek an application for an experiment that is simply curious, we yet believe that there is here a phenomenon of a nature to be studied by physicists. discoveries in telephony and microphony have certainly opened up to science, as regards both theory and practice, new horizons that still promise other surprises for the future. but to return to the observatory: the success obtained by the exhibition of the french society of physics shows that these reunions respond to a genuine need--that of instructing in and popularizing science. while warmly congratulating the organizers of these meetings, we may express a wish that the good example set by the society of physics may be followed by other societies. we are convinced in advance that an equal success awaits them.--_la nature._ * * * * * on the arrangement of ground conductors. in telegraphy, as well as in the question of lightning rods, attention has been but incidentally paid to the improvement of ground conductors, and this point has not been the object of that careful study that has been bestowed upon the establishment of aerial lines. it is only recently that the interest created by lightning rods has given rise to new forms of conductors differing from those formerly used. the publications of the prussian academy of sciences of from to contain some information of special importance in regard to this. it is stated therein that the effect of ground conductors may be notably increased by the division of the earth plates and the use of metallic rods, without necessitating a greater output of material. these facts, however, have not as yet been put to profit in practice for the reason, perhaps, that the considerations, which have remained general, have not at once permitted of obtaining forms what could be employed with perfect knowledge of the results. this is what led mr. ulbricht, of dresden, to make calculations for a few forms of conductors, and to test their approximate values. the results of these researches are printed in the _elektrotechnischen zeitschrift_ for (p. ). [illustration] the equations found show, in the first place, that there exist three means of obtaining a considerable effect, as regards the ground conductor, with a slight expenditure of material: the cylindrical electrode may be drawn out into the form of a bar or wire; the plate may be rendered narrow, and elongated in the form of a ribbon; and, besides, the annular plate may be enlarged in lessening the metallic surface. finally, a short, open cylinder with a vertical axis may be formed by curving a narrow plate or ribbon. it is not necessary to see the formula to recognize the fact that this cylinder must behave like a ribbon and a flat ring. the radius increasing, and the surface remaining constant, the resistance of the earth here likewise approaches zero. as the resistance of the earth is inversely proportional to the diameter of the plates, the zero resistance can also be reached by dividing a plate _ad infinitum_. as the parts of the plate may be brought quite close to each other without perceptibly interfering with the action, a _network_ has finally been reached by a division carried very far, yet limited, and by connecting the parts with one another by conducting cylinders. if we seek to determine what forms of ground conductors are efficient and economical under given conditions, we shall have to begin by informing ourselves as to the choice of material to be used for the electrode, and shall then have to ascertain whether putting it in the ground will or will not necessitate much outlay. the most suitable material is copper, which may be used with advantage, in that it lasts pretty well underground, and that the facility which it may be worked permits of easily giving it more appropriate forms than those that can be obtained with cast iron, which is of itself less costly. if the burying in the ground requires little or no labor, as when there exist ponds, rivers, and wells, or subterranean strata of water near the surface of the earth, elongated forms of conductors will be employed, such as the solid or hollow cylinder, the wire, the ribbon, the narrow ring, and the network. plates approaching a square or circular shape are not advantageous. but if the ground has to be dug deeply in order to sink the conductor, the form of the electrode must be more condensed, and selected in such a way that the necessary action may be obtained with a minimum output of copper and labor. for great depths, and when the ground will permit of boring, an elongated and narrow cylinder will be used. such a system, however, can only be employed when the cylinder is surrounded by spring water, since, without that, an intimate contact with earth that is only moist, cannot be obtained with certainty. in earth that is only moist and for moderate depths, preference may be given to an electrode laid down flat. the digging necessary in this case is onerous, it is true, but it permits of very accurately determining the state of the earth beneath and of obtaining a very perfect adherence of the electrode therewith. two forms, the annular ribbon or the flat ring and the network, present themselves, according to calculations, as a substitute for copper plates, which are so expensive; and these forms are satisfactory on condition that the labor of digging be not notably increased. these forms should always have a diameter a little greater than that of the plate. the flat ring and the network, however, offer one weak point, which they possess in common with the plate, and that is, their dimensions cannot be easily adapted to the nature of the ground met with without a notable increase in the expense. now, if the ground should offer a conductivity less than what was anticipated, and it were desired to increase the plate, say by one-third, it would be impossible to do so as a consequence of the closed form. one important advantage is realized in this respect by combining the ring and the network in the form of a reticulated ring having a diameter of from to ½ meters. on cutting this ring at a given place and according to a certain radius we obtain the reticulated ribbon shown in the accompanying figure. the thickness of the wires is . mm., and their weight is . kilo. per meter. l, l, and l are the points at which the conducting cable is soldered. a reticulated ribbon of copper can be made in advance of any length whatever, and, according to local exigencies, it may be easily curved and given the form of a flat or cylindrical ring of varying width. even though the ribbon has already been cut for a ring of given diameter, it may be still further enlarged by drawing it out and leaving a bit of the ring open, so as to thus obtain a nearly corresponding diminution in the resistance. such a resistance may be still further diminished by rendering the ring higher, that is to say, by employing an annular cylindrical form. after assuring himself, by experiments on a small scale, that calculation and observation gave concordant results for the flat ring, the author made an experiment on a larger scale with the annular network. for practical reasons he employed for this purpose a copper wire . mm. in diameter, which may be expected to last as long as one of iron plate mm. in thickness. calculation showed that in a ribbon mm. wide, meshes mm. in breadth were advantageous and favorable as regards rigidity. a reticulated ribbon like this, meters in length, was made and formed into a flat ring having an external diameter of . m. and an internal one of . m. the resistance of this ring was found to be w = . ( /_k_), and that of a plate one meter square, w = . ( /_k_). as the conductivity of the earth is very variable, and as we cannot have an absolute guarantee that the ramming will be uniform, it seemed proper to make the measurements of the resistance by fixing the plate and the ring in succession to the lower surface of a small raft, in such a way that the contact with the water should correspond as well as possible to the suppositions made for the calculation. as a second ground conductor, a system of water pipes was used, and, after this, a lightning rod conductor, etc. repeated and varied experiments gave, for the calculation of the values of the resistances, equations so concordant that the following results may be considered very approximate. the square plate had a resistance of . siemens units, and the reticulated ring one of . . from the first figure we deduce k = / . , that is to say, the specific conductivity of river-water is : . calculation, then, gives as the resistance of the earth in siemens units: calculated. observed. square plate. . . annular ring. . . these figures prove the accuracy of the calculations that had been made in an approximate way. the experiments were performed upon the elba, above dresden. other experiments still had reference to the influence of immersion. in order to diminish polarization, only instantaneous currents from the measuring pile were employed. it was to be supposed that the current of water through which the bubbles of gas were removed from the electrodes would not have permitted of a notable resistance of polarization. later measurements, made upon a ribbon buried, like the plates, in the earth, gave likewise most favorable results. as a result of these experiments, the state railways of saxony have, in such cases as were practicable, introduced the annular network of copper. there are some manufacturers, too, who seem desirous of adopting this system, although it has hardly emerged from the period of experiment. the pecuniary advantages that will result from an application of it ought, it would seem, to dispel a large proportion of the criticisms directed against the erection of lightning rods, from the standpoint of expense, and contribute to extend an arrangement which may be considered as a very happy one. if we compare the square plate with the equivalent annular network, constructed as above indicated, and which should possess, according to the author an external diameter of . m. and of . m., we find that: the square plate, mm. thick weighs . kilos. " " " " . " the annular network " . " the cost of reticulated ribbon per meter amounts to about . francs, supposing it to be arranged as shown in the cut. as term of comparison, we may admit that the following forms are nearly the equivalent of a horizontal, unburied plate one meter square. length. diameter. vertical cylinder buried . m. . m. " " " . m. . m. vertical bar " . m. . m. horizontal bar " . m. . m. horizontal flat ring . m. in external diameter, and . m. internal. horizontal network . m. square, and having meshes of the same size as those of the reticulated ribbon. horizontal reticulated ribbon m. in length and of the structure described. horizontal annular ring . m. in external diameter, . m. internal. in conclusion, let us meet an objection that might be made to the accuracy of the hypotheses that serve as a base to the preceding calculations, in cases where ground plates for lightning rods and not for telegraphs are concerned. between the two ground plates of a telegraph line there is generally a distance such that the curves of the current undergo no deviation in the vicinity of one of the electrodes (the only part important for integrations) through the influence of the other. but it might be admitted that such would prove the case with a lightning rod in a storm, at the time of the passage of the fluid into the earth. the ground plate here is one of the electrodes, and the other is replaced by the surface of the earth strongly charged to a great distance under the storm clouds. if we suppose (what may be admitted in a good lightning rod) that there no longer occurs any spark from the point downward, the curves of the current, in starting perpendicularly from the ground plate, would be obliged to leave their rectilinear trajectory and strike the surface of the earth at right angles. when the electricity flows through a plane surface into an infinite body, it is only when such surface presents a very great development that the respective potentials decrease very slowly in the vicinity of the said surface. no notable modification occurs, then, in the curves of equal potential, in the vicinity of the ground plate through the action of this extended charge, nor consequently any modification in the curves of the current; but the electricity which spreads has but a short distance to travel in order to overcome the most important resistances. the calculations of resistances given above have, then, the same value for discharges of atmospheric electricity.--_bull. du musee de l'industrie._ * * * * * on electrolysis. by h. schucht. concerning the separations which take place at the positive pole, the composition of the peroxides, and the manner of their determination, relatively little has been done. if solutions of the salts of lead, thallium, silver, bismuth, nickel, and cobalt are decomposed by the current between platinum electrodes, metal is deposited at the negative, and oxide at the positive electrode. manganese is precipitated only as peroxide. the formation of peroxide is, of course, effected by the ozone found in the electrolytic oxygen at the positive pole; the oxide existing in solution is brought to a higher degree of oxidation, and is separated out. its formation may be decreased or entirely prevented by the addition of readily oxidizible bodies, such as organic acids, lactose, glycerine, and preferably by an excess of oxalic acid; but only until the organic matter is transformed into carbonic acid. in this manner classen separates other metals from manganese in order to prevent the saline solutions from being retained by the peroxide. with solutions of silver, bismuth, nickel, and cobalt, it is often practicable to prevent the separation of oxide by giving the current a greater resistance--increasing the distance between the electrodes. the proportion between the quantities of metal and of peroxide deposited is not constant, and even if we disregard the concentration of the solution, the strength of the current and secondary influences (action of nascent hydrogen) is different in acid and in alkaline solutions. in acid solutions much peroxide is formed; in alkaline liquids, little or none. the reason of the difference is that ozone is evolved principally in acid solutions, but appears in small quantities only in alkaline liquids, or under certain circumstances not at all. the quantity of peroxide deposited depends also on the temperature of the saline solution; at ordinary temperatures the author obtained more peroxide--the solution, the time, and the strength of current being equal--than from a heated liquid. the cause is that ozone is destroyed by heat and converted into ordinary oxygen. with the exception of lead and thallium the quantity of metal deposited from an acid solution is always greater than that of the peroxide. _lead._--luckow has shown that from acid solutions--no matter what may be the acid--lead is deposited at the anode as a mixture of anhydrous and hydrated peroxide of variable composition. only very strongly acid solutions let all their lead fall down as peroxide; the precipitation is rapid immediately on closing the circuit, and complete separation is effected only in presence of at least per cent. of free nitric acid. as the current becomes stronger with the increase of free acid, there is deposited upon the first compact layer a new stratum of loosely adhering peroxide. in presence of small quantities of other metals which are thrown down by the current in the metallic state, such as copper, mercury, etc., peroxide alone is deposited from a solution of lead containing small quantities only of free nitric acid. the lead peroxide deposited is at first light brown or dark red, and becomes constantly darker and finally taking a velvet-black. as its stratification upon the platinum is unequal, it forms beautifully colored rings. experiments show that the quantity of peroxide deposited depends on the nature of the solution and the strength of the current. in case of very feeble currents and slight acidity, its quantity is so small that it does not need to be taken into consideration. if the lead solution is very dilute scarcely any current is observed, lead solutions _per se_ being very bad conductors of electricity. faintly acid concentrated lead solutions give loose peroxide along with much spongy metallic lead. free alkali decreases the separation of peroxide; feebly alkaline solutions, concentrated and dilute, yield relatively much peroxide along with metallic lead, while strongly alkaline solutions deposit no peroxide. dried lead peroxide is so sparingly hygroscopic that it may be weighed as such; its weight remains constant upon the balance for a long time. in order to apply the peroxide for quantitative determinations, a large surface must be exposed to action. as positive electrode a platinum capsule is convenient, and a platinum disk as negative pole. the capsule shape is necessary because the peroxide when deposited in large quantities adheres only partially, and falls in part in thin loose scales. it is necessary to siphon off the nitric solution, since, like all peroxides, that of lead is not absolutely insoluble in nitric acid. the methods of riche and may give results which are always too high, since portions of saline solution are retained by the spongy deposit and can be but very imperfectly removed by washing. this is especially the case in presence of free alkali. the author has proceeded as follows: the lead peroxide is dried in the capsule, and there is passed over it pure dry gaseous sulphurous acid in a strong current from a rather narrow delivery tube. lead sulphate is formed with evolution of heat; it is let cool under the exsiccator, and weighed as such. or he ignites the peroxide along with finely pulverized ammonium sulphite; the mass must have a pure white color. after the conclusion of the reaction it is ignited for about minutes. the results are too high. the proportion of actual lead peroxide in the deposit ranges from to . per cent. the peroxide precipitated from a nitric solution may, under certain circumstances, be anhydrous. this result is due to the secondary influences at the positive pole, where the free acid gradually withdraws water from the peroxide. the peroxide thrown down from alkaline solutions retains alkali so obstinately that it cannot be removed by washing; the peroxide plays here the part of an acid. the lead nitrate mechanically inclosed in the peroxide is resolved by ignition into oxide, hyponitric acid, and oxygen; this small proportion of lead oxide does not exert an important influence on the final result. the quantity of matter mechanically inclosed is relatively high, as in the precipitation of much lead peroxide there is relatively more saline matter occluded than when a few centigrammes are deposited. the peroxide incloses also more foreign matter if it is thrown down upon a small surface than if it is deposited in a thin layer over a broad surface. from numerous analyses the author concludes that in presence of much free nitric acid the proportion of water is increased; with free alkali the reverse holds good. _thallium_ behaves similarly to lead. from a nitric acid solution it is thrown down, according to the proportion of free acid, either as sesquioxide only or in small quantities as silvery, metallic leaflets; from alkaline solutions it is deposited as sesquioxide and metal, the latter of a lead-gray color. thallium solutions conduct the electric current badly. thallium oxide resembles lead peroxide in color; at a strong heat it melts, becomes darker, and is converted into peroxide, in which state it can be weighed. _silver._--all solutions of silver salts, except the nitrate, and those containing a very large quantity of free nitric acid or nitrates, deposit electrolytically merely metallic silver. in the above mentioned exceptional cases there is formed a small quantity of peroxide which adheres to the anode as a blackish-gray deposit. the greatest quantity of peroxide is obtained on employing a concentrated, strongly acid solution of the nitrate, and a strong current. if the solution is very dilute we obtain no peroxide, or mere traces which disappear again toward the end of the process. the peroxide is deposited at first in small, dark, shining octahedral crystals; subsequently, in an amorphous state. at ° it evolves oxygen suddenly, and is converted into metallic silver. it dissolves in ammonia with a violent escape of nitrogen. in nitric acid it dissolves without decomposition and with a red color. the author uses a galvanic current for reducing silver residues, consisting of sulphocyanide. the salt is mixed with sulphuric acid in a roomy platinum capsule, and a fine platinum wire gauze is used as positive electrode. _bismuth._--the current resolves bismuth solutions into metal and bismutic acid. the latter is deposited at the positive pole, and in thin layers appears of a golden-yellow, but in thick strata is darker, approaching to red. its formation is very gradual, and in time it disappears again, owing to secondary actions of the current. on ignition it becomes lemon yellow, and transitorily darker, even brown, and passes into the sexquioxide. _nickel and cobalt._--on the electrolysis of the ammonical solution the sesquioxide appears at the positive pole. its formation is prevented by an excess of ammonia. the author never obtains more than ½ per cent. of the quantity of the metal. the sesquioxides dissolve in ammonia without escape of nitrogen, and are usually anhydrous. _manganese._--manganese is the only metal which is precipitated only as peroxide. it is deposited at once on closing the circuit, and is at first brown, then black and shining. organic acids, ferrous oxide, chromic oxide, ammonium salts, etc., prevent the formation of peroxide and the red color produced by permanganic acid. in very dilute strongly acid nitric solutions there is formed only permanganic acid, which according to riche is plainly visible in solutions containing / grm. manganese. on electrolyzing a manganiferous solution of copper nitrate, red permanganic acid appeared in a stratum floating above the platinum disk coated with brown peroxide. no manganese peroxide was deposited. the peroxide adheres firmly to the platinum when the proportion of free acid is small, not exceeding per cent., and the current is not too strong. if the action of the current is prolonged after the peroxide is thrown down, it falls off in laminæ. according to riche, in a nitric solution the manganese is deposited as peroxide, also at the negative pole. this formation is not directly due to the current, but is a precipitate occasioned by the production of ammonia by the reduction of nitric acid. to determine the manganese in peroxide electrolytically precipitated, it is heated to bright redness in the platinum capsule until the weight becomes constant. the results are too high. _selenium and tellurium._--both these bodies are readily and completely reduced by the current either in acid or alkaline solutions. selenium is thrown down at first of a fine brownish red, which gradually becomes darker. the deposit of tellurium is of a bluish black color. if the current is feeble, the deposit of selenium is moderately compact; that of tellurium is always loose, and it often floats on the liquid. a strong current precipitates both as powders. the positive pole is coated during electrolysis with a film of a dark color in case of selenium, but of a lemon yellow with tellurium. as in case of arsenic and antimony, the hydrogen evolved at the negative pole combines with the reduced substances, forming hydrogen, selenide, or telluride, which remain in part in solution in the liquid. the reduced metal separates out at the anode in a friable condition.--_zeitschrift fur analytische chemie, and chemical news._ * * * * * the electro-chemical equivalent of silver. a very careful and important determination of the electrochemical equivalent of silver has been made at the observatory of the physical institute of würzbourg, and the results are that an ampere current flowing for a second, or a coulomb of electricity deposits . milligrammes of silver or . milligramme of copper, and decomposes . milligramme of water, a result agreeing closely with that of lord rayleigh recently communicated to the physical society. an ampere therefore deposits . grammes of silver per hour; kohlrausch's value is . , a value hitherto accepted universally. this value is so useful in measuring electric currents with accuracy, and free from the disturbances of magnetism, etc., that it is eminently satisfactory to find the german value agree with that of lord rayleigh, which will probably be adopted by english electricians. * * * * * a new standard light. herr hefner-alteneck has suggested a new standard light for photometric purposes, which promises to be very simple and effective in operation. the light is produced by an open flame of amyl-acetate burning from a wick of cotton fiber which fills a tube of german silver in. long and mils. internal diameter; the external diameter being mils. the flame is . in. high from top to bottom; and it should be lighted at least ten minutes before using the light for testing. a cylindrical glass chimney surrounds it to ward off air currents. about per cent. of the light is absorbed by the glass. the power of the flame is that of a standard english candle; and experiments have shown that amyl acetate, which besides is not expensive, is the best fuel for steadiness and brilliance. neither the substitution of commercial amyl-acetate for pure nor the use of a wick of cotton thread for loose cotton fiber alters the illuminating power; but the wick should be trimmed square across the mouth of the tube, for if it project and droop the illuminating power is increased. * * * * * [nature.] dr. feussner's new polarizing prism. in a recent number of the _zeitschrift fur instrumentenkunde_ (iv., - , february, ), dr. k. feussner of karlsruhe has given a detailed description of a polarizing prism lately devised by him, which presents several points of novelty, and for which certain advantages are claimed. the paper also contains an account, although not an exhaustive one, of the various polarizing prisms which have from time to time been constructed by means of different combinations of iceland spar. the literature of this subject is scattered and somewhat difficult of access, and moreover only a small part of it has hitherto been translated into english; and it would appear therefore that a brief abstract of the paper may not be without service to those among the readers of _nature_ who may be unacquainted with the original memoirs, or who may not have the necessary references at hand. following the order adopted by dr. feussner, the subject may be divided into two parts: i.--older forms of polarizing prisms. in comparing the various forms of polarizing prisms, the main points which need attention are--the angular extent of the field of view, the direction of the emergent polarized ray, whether it is shifted to one side of, or remains symmetrical to the long axis of the prism; the proportion which the length of the prism bears to its breadth; and lastly, the position of the terminal faces, whether perpendicular or inclined to the long axis. these requirements are fulfilled in different degrees by the following methods of construction: [illustration: fig. ., fig. ., and fig. .] . _the nicol prism_ (_edin. new phil. journal_, , vi., ).--this (fig. ), as is well known, is constructed from a rhombohedron of iceland spar, the length of which must be fully three times as great as the width. the end faces are cut off in such a manner that the angle of ° which they originally form with the lateral edge of the rhombohedron is reduced to °. the prism is then cut in two in a plane perpendicular to the new end surfaces, the section being carried obliquely from one obtuse corner of the prism to the other, in the direction of its length. the surfaces of this section, after having been carefully polished, are cemented together again by means of canada balsam. a ray of light, on entering the prism, is separated by the double refraction of the calc-spar into an ordinary and an extraordinary ray; the former undergoes total reflection at the layer of balsam at an incidence which allows the extraordinary ray to be transmitted; the latter, therefore, passes through unchanged. this principle of obtaining a single polarized ray by means of total reflection of the other is common to all the forms of prism now to be described. dr. feussner gives a mathematical analysis of the paths taken by the two polarized rays within the nicol prism, and finds that the emergent extraordinary ray can include an angular field of °, but that this extreme value holds good only for rays incident upon that portion of the end surface which is near to the obtuse corner, and that from thence it gradually decreases until the field includes an angle of only about half the previous amount. he finds, moreover, that, although of course the ray emerges parallel to its direction of incidence, yet that the zone of polarized light is shifted to one side of the central line. also that the great length of the nicol-- . times its breadth--is not only an inconvenience, but owing to the large pieces of spar thus required for its construction, prisms of any but small size become very expensive. to this it may be added that there is a considerable loss of light by reflection from the first surface, owing to its inclined position in regard to the long axis of the prism. [illustration: fig. ., fig. ., and fig. .] it is with the view of obviating these defects that the modifications represented in figs. to have been devised. . _the shortened nicol prism_.--this arrangement of the nicol prism is constructed by dr. steeg and reuter of homburg v.d.h. for the sake of facility of manufacture, the end surfaces are cleavage planes, and the oblique cut, instead of being perpendicular, makes with these an angle of about °. by this alteration the prism becomes shorter, and is now only . times its breadth; but if canada balsam is still used as the cement, the field will occupy a very unsymmetrical position in regard to the long axis. if balsam of copaiba is made use of, the index of refraction of which is . , a symmetrical field of about ° will be obtained. a prism of this kind has also been designed by prof. b. hasert of eisenach (_pogg. ann._, cxiii., ), but its performance appears to be inferior to the above. . _the nicol prism with perpendicular ends._--the terminal surfaces in this prism are perpendicular to the long axis, and the sectional cut makes with them an angle of about °. the length of the prism is . times its breadth, and if the cement has an index of refraction of . , the field is symmetrically disposed, and includes an angle of °. prisms of this kind have been manufactured by dr. steeg, mr. c.d. ahrens, and others. . _the foucault prism_ (_comptes rendus_, , xlv., ).--this construction differs from all those hitherto mentioned, in that a film of air is employed between the two cut surfaces as the totally reflecting medium instead of a layer of cement. the two halves of the prism are kept in position, without touching each other, by means of the mounting. the length of the prism is in this way much reduced, and amounts to only . times its breadth. the end surfaces are cleavage planes, and the sectional cut makes with them an angle of °. the field, however, includes not more than about °, so that this prism can be used only in the case of nearly parallel rays; and in addition to this the pictures which may be seen through it are to some extent veiled and indistinct, owing to repeated internal reflection. . _the hartnack prism_ (_ann. de ch. et de physique_, ser. iv., vii., ).--this form of prism was devised in by mm. hartnack and prazmowiski; the original memoir is a valuable one; a translation of it, with some additions, has lately been published (_journ. of the r. microscopical soc._, june, , ). it is considered by dr. feussner to be the most perfect prism capable of being prepared from calc-spar. the ends of the prism are perpendicular to its length; the section carried through it is in a plane perpendicular to the principal axis of the crystal. the cementing medium is linseed oil, the index of refraction of which is . . this form of prism is certainly not so well known in this country as it deserves to be; a very excellent one, supplied to the present writer by dr. steeg is of rectangular form throughout, the terminal surfaces are × mm., and the length mm. the lateral shifting of the field is scarcely perceptible, the prism is perfectly colorless and transparent, and its performance is far superior to that of the ordinary nicol. the field of view afforded by this construction depends upon the cementing substance used, and also upon the inclination of the sectional cut in regard to the end of the prism; it may vary from ° to °. if the utmost extent of field is not required, the prism may be shortened by lessening the angle of the section, at the expense, however, of interfering with the symmetrical disposition of the field. . _the glan prism_ (carl's "repertorium," xvi., , and xvii., ).--this is a modification of the foucault, and in a similar manner includes a film of air between the sectional surfaces. the end surfaces and also the cut carried through the prism are parallel to the principal axis of the calc-spar. the ends are normal to the length, and the field includes about °. this prism is very short, and may indeed be even shorter than it is broad. it is subject to the same defect as that mentioned in the case of the foucault, although perhaps not quite to the same extent. ii.--the new polarizing prism. this prism differs very considerably from the preceding forms, and consists of a thin plate of a doubly refracting crystal cemented between two wedge-shaped pieces of glass, the terminal faces of which are normal to the length. the external form of the prism may thus be similar to the hartnack, the calc-spar being replaced by glass. the indices of refraction of the glass and of the cementing medium should correspond with the greater index of refraction of the crystal, and the directions of greatest and least elasticity in the latter must stand in a plane perpendicular to the direction of the section. one of the advantages claimed for the new prism is that, it dispenses with the large and valuable pieces of spar hitherto found necessary; a further advantage being that other crystalline substances may be used in this prism instead of calc-spar. the latter advantage, however, occurs only when the difference between the indices of refraction for the ordinary and extraordinary rays in the particular crystal made use of is greater than in calc-spar. when this is the case, the field becomes enlarged, and the length of the prism is reduced. [illustration: fig. .] the substance which dr. feussner has employed as being most suitable for the separating crystal plate is nitrate of soda (_natronsalpeter_), in which the above-mentioned values are [omega] = . and [eta] = . . it crystallizes in similar form to calcite, and in both cases thin plates obtained by cleavage may be used. as the cementing substance for the nitrate of soda, a mixture of gum dammar with monobromonaphthalene was used, which afforded an index of refraction of . . in the case of thin plates of calcite, a solid cementing substance of sufficiently high refractive power was not available, and a fluid medium was therefore employed. for this purpose the whole prism was inclosed in a short glass tube with airtight ends, which was filled with monobromonaphthalene. in an experimental prism a mixture of balsam of tolu was made use of, giving a cement with an index of refraction of . , but the low refractive power resulted in a very considerable reduction of the field. the extent and disposition of the field may be varied by altering the inclination at which the crystal lamina is inserted (fig. ), and thereby reducing the length of the prism, as in the case of the hartnack. in order to obviate the effects of reflection from the internal side surfaces if the prism, the wedge-shaped blocks of glass of which it is built up may be made much broader than would otherwise be necessary; the edges of this extra width are cut obliquely and suitably blackened. the accompanying diagram (fig. ) represents a prism of cylindrical external form constructed in this manner, the lower surface being that of the incident light. in this the field amounts to °, and the breadth is about double the length. [illustration: fig. .] dr. feussner remarks that a prism similar in some respects to his new arrangement was devised in by m. jamin (_comptes rendus_, lxviii., ), who used a thin plate of calc-spar inclosed in a cell filled with bisulphide of carbon; and also by dr. zenker, who replaced the liquid in m. jamin's construction by wedges of flint glass. among others, the carefully considered modifications of the nicol prism which have recently been devised by prof. s.p. thompson (_phil. mag._, november, , , and _jour. r. micros. soc._, august, , ), and by mr. r.t. glazebrook (_phil. mag._, may, , ), do not appear to have been known to dr. feussner. the following tabular view of different forms of polarizing prisms is taken from the conclusion of dr. feussner's paper: ---------------------------------------+------+---------+------+------ | |inclina- |ratio | | |tion of | of | | |section |length| | |in regard| to | | |to long |clear | |field.|axis. |width.|fig. ---------------------------------------+------+---------+------+------ i. the old polarising prisms. | ° | ° | | . nicol's prism. | | | . | . shortened nicol prism-- | | | | a. cemented with canada balsam.| | | . | b. cemented with copaiba " | | | . | . nicol with perpendicular ends-- | | | | a. with canada balsam. | | | . | b. with cement of index of | | | | refraction of . . | | | . | . foucault's prism. | | | . | . hartnack's prism-- | | | | a. original form. | | . | . | _a b_ b. with largest field. | . | . | . | _a a_ c. with field of °. | | . | . | _a c_ d. with field of °. | | . | . | _a d_ . glan's prism. | . | . | . | | | | | ii. the new polarising prism. | | | | . with calc-spar: largest field. | | . | . | _a a_ . " field of °. | | . | . | _a c_ . " field of °. | | . | . | _a d_ . with nitrate of soda: | | | | " largest field. | | . | . | _a a_ . " field of °. | | | . | _a b_ . " field of °. | | | . | _a c_ ---------------------------------------+------+---------+------+------ as an analyzing prism of about mm. clear width, and . mm. long, the new prism is stated by its inventor to be of the most essential service, and it would certainly appear that the arrangement is rather better adapted for small prisms than for those of considerable size. any means by which a beam of polarized light of large diameter--say to ½ inches--could be obtained with all the convenience of a nicol would be a real advance, for spar of sufficient size and purity for such a purpose has become so scarce and therefore so valuable that large prisms are difficult to procure at all. so far as an analyzer is concerned, the experience of the writer of this notice would lead to the opinion that improvements are to be looked for rather in the way of the discovery of an artificial crystal which absorbs one of the polarized rays than by further modifications depending upon total reflection. the researches of dr. herapath on iodosulphate of quinine (_phil. mag._, march, , , and november, , ) are in this direction; but crystals of the so-called herapathite require great manipulative skill for their production. if these could be readily obtained of sufficient size, they would be invaluable as analyzers. this opinion is supported by the existence of an inconvenience which attends every form of analyzing prism. it is frequently, and especially in projecting apparatus, required to be placed at the focus of a system of lenses, so that the rays may cross in the interior of the prism. this is an unfavorable position for a prismatic analyzer, and in the case of a powerful beam of light, such as that from the electric arc, the crossing of the rays within the prism is not unattended with danger to the cementing substance, and to the surfaces in contact with it. philip r. sleeman. * * * * * zircon. by f. stolba. finely ground zircon is quickly rendered soluble if fused with a mixture of potassium borofluoride and potassium carbonate. the author takes two parts of the former to three of the latter, and prepares an intimate, finely divided mixture, which is kept ready for use. of this mixture four parts are taken to one of zircon, thoroughly mixed, and melted in a platinum crucible at a red heat. the mass fuses readily, froths at first and gives off bubbles of gas, and flows then quietly, forming a very fluid melt. if the zircon is finely ground, minutes are sufficient for this operation. the loss of weight is per cent., and is not notably increased on prolonged fusion. it corresponds approximately to the weight of the carbonic anhydride present in the potassium carbonate. as pungent vapors are given off during fusion, the operation should be conducted under a draught hood. the activity of the mixture in attacking zircon appears from the following experiment: two zircon crystals, each weighing ½ grm., were introduced into the melted mixture and subjected to prolonged heat. in a short time they decreased perceptibly in size; each of them broke up into two fragments, and within an hour they were entirely dissolved. the melted mass is poured upon a dry metal plate, and when congealed is thrown into water. it is at once intersected with a number of fissures, which facilitate pulverization. this process is the more necessary as the unbroken mass is very slowly attacked by water even on prolonged boiling. the powder is boiled in a large quantity of water so as to remove everything soluble. there is obtained a faintly alkaline solution and a sediment insoluble in water. from the filtrate alkalies throw down zirconium hydroxide, free from iron. the portion insoluble in water is readily dissolved in hydrofluoric acid, and is converted into zircon potassium fluoride. the chief bulk of the zirconium is found in the aqueous solution in the state of double fluorides. the platinum crucible is not in the least attacked during melting. on the contrary, dirty platinum crucibles may be advantageously cleaned by melting in them a little of the above mentioned mixture. if finely divided zircon is boiled for a long time with caustic lye, it is perceptibly attacked. it is very probable that in this manner zircon might be entirely dissolved under a pressure of atmospheres. potassium borofluoride may be readily prepared from cryolite. crucibles of nickel seem especially well adapted for the fusion of zircon in caustic alkalies.--_ber. boehm. gesell. wissenschaft; chem. news_. * * * * * a process for making wrought iron direct from the ore.[ ] [footnote : a paper read at the cincinnati meeting of the american institute of mining engineers, by willard p. ward, a.m., m.e., february, .] the numerous direct processes which have been patented and brought before the iron masters of the world, differ materially from that now introduced by mr. wilson. after a careful examination of his process, i am convinced that mr. wilson has succeeded in producing good blooms from iron ore, and i think that i am able to point out theoretically the chief reasons of the success of his method. without going deeply into the history of the metal, i may mention the well known fact that wrought iron was extensively used in almost all quarters of the globe, before pig or cast iron was ever produced. without entering into the details of the processes by which this wrought iron was made, it suffices for my present purpose to say that they were crude, wasteful, and expensive, so that they can be employed to-day only in a very few localities favored with good and cheap ore, fuel, and labor. the construction of larger furnaces and the employment of higher temperatures led to the production of a highly carbonized, fusible metal, without any special design on the part of the manufacturers in producing it. this pig iron, however, could be used only for a few purposes for which metallic iron was needed; but it was produced cheaply and with little loss of metal, and the attempt to decarbonize this product and bring it into a state in which it could be hammered and welded was soon successfully made. this process of decarbonization, or some modification of it, has successfully held the field against all so-called, direct processes up to the present time. why? because the old fashioned bloomeries and catalan forges could produce blooms only at a high cost, and because the new processes introduced failed to turn out good blooms. those produced were invariably "red short," that is, they contained unreduced oxide of iron, which prevented the contact of the metallic particles, and rendered the welding together of these particles to form a solid bloom impossible. the process of puddling cast iron, and transforming it by decarbonization into wrought iron, has, as everybody knows, been in successful practical operation for many years, and the direct process referred to so closely resembles this, that a short description of the theory of puddling is not out of place here. the material operated on in puddling is iron containing from ½ to per cent. of carbon. during the first stage of the process this iron is melted down to a fluid bath in the bottom of a reverberatory furnace. then the oxidation of the carbon contained in the iron commences, and at the same time a fluid, basic cinder, or slag, is produced, which covers a portion of the surface of the metal bath, and prevents too hasty oxidation. this slag results from the union of oxides of iron with the sand adhering to the pigs, and the silica resulting from the oxidation of the silicon contained in the iron. this cinder now plays a very important part in the process. it takes up the oxides of iron formed by the contact of the oxidizing flame with the exposed portion of the metal bath, and at the same time the carbon of the iron, coming in contact with the under surface of the cinder covering, where it is protected from oxidizing influences, reduces these oxides from the cinder and restores them to the bath in metallic form. this alternate oxidation of exposed metal, and its reduction by the carbon of the cast iron, continues till the carbon is nearly exhausted, when the iron assumes a pasty condition, or "comes to nature," as the puddlers call this change. the charge is then worked up into balls, and removed for treatment in the squeezer, and then hammered or rolled. in the wilson process the conditions which we have noted in the puddling operation are very closely approximated. iron ore reduced to a coarse sand is mixed with the proper proportion of charcoal or coke dust, and the mixture fed into upright retorts placed in the chimney of the puddling furnace. by exposure for hours to the heat of the waste gases from the furnace, in the presence of solid carbon, a considerable portion of the oxygen of the ore is removed, but little or no metallic iron is formed. the ore is then drawn from the deoxidizer into the rear or second hearth of the puddling furnace, situated below it, where it is exposed for minutes to a much higher temperature than that of the deoxidizer. here the presence of the solid carbon, mixed with the ore, prevents any oxidizing action, and the temperature of the mass is raised to a point at which the cinder begins to form. then the charge is carried forward by the workmen to the front hearth, in which the temperature of a puddling furnace prevails. here the cinder melts, and at the same time the solid carbon reacts on the oxygen remaining combined with the ore, and forms metallic iron; but by this time the molten cinder is present to prevent undue oxidation of the metal formed, and solid carbon is still present in the mixture to play the same role, of reducing protoxide of iron from the cinder, as the carbon of the cast iron does in the ordinary puddling process. i have said that the cast iron used as the material for puddling contains about per cent. of carbon; but in this process sufficient carbon is added to effect the reduction of the ore to a metallic state, and leave enough in the mass to play the part of the carbon of the cast iron when the metallic stage has been reached. it would be interesting to compare the wilson with the numerous other direct processes to which allusion has already been made, but there have been so many of them, and the data concerning them are so incomplete, that this is impossible. two processes, however, the blair and the siemens, have attracted sufficient attention, and are sufficiently modern to deserve notice. in the blair process a metallic iron sponge was made from the ore in a closed retort, this sponge cooled down in receptacles from which the air was excluded, to the temperature of the atmosphere, then charged into a puddling furnace and heated for working. in this way (and the same plan essentially has been followed by other inventors), the metallic iron, in the finest possible state of subdivision, is subjected to the more or less oxidizing influences of the flame, without liquid slag to save it from oxidation, and with no carbon present to again reduce the iron oxides from the cinder after it is formed. the loss of metal is consequently very large, but oxides of iron being left in the metal the blooms are invariably "red short." in the siemens process pieces of ore of the size of beans or peas, mixed with lime or other fluxing material, form the charge, which is introduced into a rotating furnace; and when this charge has become heated to a bright-red heat, small coal of uniform size is added in sufficient quantity to effect the reduction of the ore. the size of the pieces of the material employed prevents the intimate mixture of the particles of iron with the particles of carbon, and hence we would, on theoretical grounds, anticipate just what practice has proved, viz., that the reduction is incomplete, and the resulting metal being charged with oxides is red-short. in practice, blooms made by this process have been so red-short that they could not be hammered at all. it would be impracticable in this process to employ ore and carbon in as fine particles as wilson does, as a very large portion of the charge would be carried off by the draught, and a sticking of the material to the sides of the rotating furnace could scarcely be avoided. i do not imagine that a division of the material into anything like the supposed size of molecules is necessary; we know that the graphitic carbon in the pig-iron employed in puddling is not so finely divided, but it is much smaller particles than bean or pea size, and by approximating the size of the graphite particles in pig iron, wilson has succeeded in obtaining good results. if we examine the utilization of the heat developed by the combustion of a given quantity of coal in this process, and compare it with the result of the combustion of an equivalent amount of fuel in a blast furnace, we shall soon see the theoretical economy of the process. the coal is burned on the grate of the puddling-furnace, to carbonic acid, and the flame is more fully utilized than in an ordinary puddling-furnace, for besides the ordinary hearth there is the second or rear hearth, where additional heat is taken up, and then the products of combustion are further utilized in heating the retorts in which the ore is partly reduced. after this the heat is still further utilized by passing it under the boilers for the generation of steam, and the heat lost in the gases, when they finally escape, is very small. in a blast furnace the carbon is at first burned only to carbonic oxide, and the products of combustion issue mainly in this form from the top of the furnace. then a portion of the heat resulting from the subsequent burning of these gases is pretty well utilized in making steam to supply the power required about the works, but the rest of the gas can only be utilized for heating the blast, and here there is an enormous waste, the amount of heat returned to the furnace by the heated blast being very small in proportion to the amount generated by the burning of that portion of carbonic oxide expended in heating it, and the gases escape from both the hot-blast and the boilers at a high temperature. in the direct process under consideration the fuel burned is more completely utilized than in the puddling process, to which the cast iron from the blast furnace is subjected to convert it into wrought iron. the economy claimed for this process, over the blast furnace and puddling practice for the production of wrought iron, is that nearly all the fuel used in the puddling operation is saved, and that with about the same amount of fuel used in the blast furnace to produce a ton of pig iron, a ton of wrought iron blooms can be made. i had no opportunity of weighing the charges of ore and coal used, but i saw the process in actual operation at rockaway, n.j. the iron produced was hammered up into good solid blooms, containing but little cinder. the muck-bar made from the blooms was fibrous in fracture, and showed every appearance of good iron. i am informed by the manager of the sanderson brothers' steel works, at syracuse, n.y., that they purchased blooms made by the wilson process in - , that _none_ of them showed red-shortness, and that they discontinued their use only on account of the injurious action of the titanium they contained on the melting pots. these blooms were made from magnetic sands from the long island and connecticut coasts. [illustration: new process for making wrought iron from the ore.] the drawing given shows the construction of the furnace employed. i quote from the published description: "the upper part, or deoxidizer, is supported on a strong mantel plate resting on four cast iron columns. "the retorts and flues are made entirely of fire-brick, from special patterns. the outside is protected by a wrought iron jacket made of no. iron. the puddling furnace is of the ordinary construction, except in the working bottom, which is made longer to accommodate two charges of ore, and thus utilize more of the waste heat in reducing the ore to metallic iron. "the operation of the furnace is as follows: the pulverized ore is mixed with per cent. of pulverized charcoal or coke, and is fed into an elevator which discharges into the hopper on the deoxidizer leading into the retorts marked c. these retorts are proportioned so that they will hold ore enough to run the puddling furnace hours, the time required for perfect deoxidation. after the retorts are filled, a fire is started in the furnace, and the products of combustion pass up through the main flue, or well, b, where they are deflected by the arch, and pass out through suitable openings, as indicated by arrows, into the down-takes marked e, and out through an annular flue, where they are passed under a boiler. "it will be noticed that the ore is exposed to the waste heat on three sides of the retorts, and owing to the great surface so exposed, the ore is very thoroughly deoxidized, and reduced in the retorts before it is introduced into the puddling furnace for final reduction. the curved cast iron pipes marked d are provided with slides, and are for the purpose of introducing the deoxidized ore into the second bottom of the furnace. as before stated, the furnace is intended to accommodate two charges of ore, and as fast as it is balled up and taken out of the working bottom, the charge remaining in the second bottom is worked up in the place occupied by the first charge, and a _new_ charge is introduced. as fast as the ore is drawn out from the retorts the elevator supplies a new lot, so that the retorts are always filled, thus making the process continuous." the temperature of the charge in the deoxidizer is from ° to , ° f.--_amer. engineer._ * * * * * some remarks on the determination of hardness in waters. by herbert jackson. having had occasion some short time ago to examine a hard water which owed half its hardness to salts of magnesium, i noticed that the soap test, applied in the usual way, gave a result which differed very much from that obtained by the quantitative estimation of calcium and magnesium. a perfectly normal lather was obtained when soap had been added in quantities sufficient to neutralize ° of hardness, whereas the water contained salts of calcium and magnesium equivalent, on clark's scale, to a hardness of °. although i was aware that similar observations had been made before, i thought that it might be useful to determine the conditions under which the soap test could not be depended upon for reliable results. i found with waters containing calcium or magnesium alone that, whenever salts of either of these metals were in solution in quantities sufficient to give ° of hardness on clark's scale, no dependence could be placed upon the results given by the soap test. in the case of waters containing salts of both calcium and magnesium, i found that if the salts of the latter metal were in solution in quantities sufficient to give more than ° of hardness, no evidence could be obtained of their presence so long as the salts of calcium in the same water exceeded °; in such a case a perfect and permanent lather was produced when soap had been added equivalent to ° of hardness. if any water be diluted so as to reduce the proportions of the salts of calcium and magnesium below those stated above, perfectly reliable results will of course be obtained. instead of dilution i found that heating the water to about ° c. was sufficient to cause a complete reaction between the soap and the salts of calcium and magnesium, even if these were present in far larger quantities than any given here. the experiments so far had all been made with a solution of castile soap of the strength suggested by mr. wanklyn in his book on "water analysis." my attention was next directed to the use of any one of the compounds of which such a soap is composed. i commenced with sodium oleate, and found that by employing this substance in a moderately pure condition, perfectly reliable results could be obtained in very hard waters without the trouble of either diluting or heating. i was unable to try sodium stearate directly because of the slight solubility of this substance in cold water or dilute alcohol; but i found that a mixture of sodium oleate and stearate behaved in exactly the same manner as the castile soap. i am not prepared at present to state the exact reaction which takes place between salts of calcium and magnesium and a compound soap containing sodium oleate and stearate. i publish these results because i have not noticed anywhere the fact that some waters show a greater hardness with soap when their temperatures approach the boiling point than they do at the average temperature of the air, it being, i believe, the ordinary impression that cold water wastes more soap than hot water before a good and useful lather can be obtained, whereas with very many waters the case is quite the reverse. neither am i aware at present whether it is well known that the use of sodium oleate unmixed with sodium stearate dispenses with the process of dilution even in very hard waters.--_chem. news._ * * * * * the density and pressure of detonating gas mixtures. mm. berthelot and vielle have recently been studying the influence of the density of detonating gaseous mixtures upon the pressure developed. the measure of pressure developed by the same gaseous system, taken under two initial states of different density to which the same quantity of heat is communicated, is an important matter in thermodynamics. if the pressures vary in the same ratio as the densities, we may conclude, independently of all special hypotheses on the laws of gases, first, that the specific heat of the system is independent of its density (that is to say, of its initial pressure), and depends only on the absolute temperature, whatever that may mean; and secondly, that the relative variation of the pressure at constant volume, produced by the introduction of a determinate quantity of heat, is also independent of the pressure, and a function only of the temperature. lastly, the pressure itself will vary proportionally with the absolute temperature, as defined by the theory of a perfect gas, and will serve to determine it. mm. berthelot and vielle operated with a bomb, at first kept at ordinary temperatures in the air, and afterward heated in an oil bath to deg. cent. they also employed isomeric mixtures of the gases; methylic ether, cyanogen, hydrogen, acetylene, and other gases were experimented upon, and the general conclusions are as follows: . the same quantity of heat being furnished to a gaseous system, the pressure of the system varies proportionally to the density of the system. . the specific heat of the gas is sensibly independent of the density as well toward very high temperatures as about deg. cent. this is all true for densities near to those that the gas possesses cold under normal pressure, and which varied in the experiment to double the original value. . the pressure increases with the quantity of heat furnished to the same system. . the apparent specific heat increases parallel with this quantity of heat. these conclusions are independent of all hypotheses on the nature and laws of gases, and were simply drawn from the experiments in question. * * * * * turkish baths for horses. the turkish bath has become an established institution in this country; men of all classes now use it for sanitary as well as remedial purposes. athletes of various descriptions find it invaluable in "training," and all the distinguished jockeys and light weights keep themselves in condition by its use. it was thought probable that what was good for man might also be good for the horse, and the fact has been proved. messrs. pickford, the eminent carriers, in their hospital for horses at finchley, have had a bath in operation over eleven years, and find the horses derive great benefit from its use. the bath is put in operation three days a week, and is administered to over twenty horses in this time. the value of the bath having been thus proved, it is rather strange that it has not been more generally adopted by the large carrying firms. however, the great northern railway company at their new hospital for horses at totteridge, are erecting a very complete turkish bath. it consists of three rooms. first, a large wash room or grooming room, from which is entered the first hot room, or tepidarium, from ° to ° fahr.; from this room, the horse, after being thoroughly acclimated, can, if necessary, pass to the hottest room, or calidarium, from ° to ° fahr., and without any turning round can pass on into the grooming and washing room again. this last room is slightly heated from the two other rooms, and in each are stocks in which the animal can he fastened if required. the heating is done most economically by constantine's convoluted stove, and thorough ventilation is secured from the large volume of hot air constantly supplied, which passes through the baths, and as it becomes vitiated is drawn off by specially designed outlets. the wash room is supplied with hot and cold water, which can, of course, be mixed to any required temperature.--_building news._ [illustration] || |+-------------------------------------------------------+ |+-------------------++---__-------____------------__---+| || ||foul air foul air foul air|| || || || || || || || || ============== || || / / || || / / st hot room || || / / || || / / ============== || || || || / =======+ || || / || || curtain|| washing room|| |+=========================== =|| \ || || || \ =======+ || || || || || || \ \ ============== || || \ \ || || \ \ nd hot room || fresh || \ \ || / air || || ============== ||== || || +======|| | || || | warm || | || ||foul air foul air| air || | |+-------------------++---__--+===+---------__----------+|== |+----------------------------|_|_|---------------------+| || | ||||| | || || | ||||| | || || |============ s t o k e r y || || || || || || || || |+-----------------------------------|| +-------------------------------------+ * * * * * miryachit, a newly described disease of the nervous system, and its analogues.[ ] [footnote : read before the new york neurological society, february , .] by william a. hammond, m.d., surgeon-general, u.s. army (retired list); professor of diseases of the mind and nervous system in the new york post-graduate medical school and hospital. in a very interesting account of a journey from the pacific ocean through asia to the united states, by lieutenant b.h. buckingham and ensigns george c. foulk and walter mclean,[ ] united states navy, i find an affection of the nervous system described which, on account of its remarkable characteristics, as well as by reason of certain known analogies, i think should be brought to the special notice of the medical profession. i quote from the work referred to, the following account of this disease. the party is on the ussuri river not far from its junction with the amur in eastern siberia: "while we were walking on the bank here we observed our messmate, the captain of the general staff (of the russian army), approach the steward of the boat suddenly, and, without any apparent reason or remark, clap his hands before his face; instantly the steward clapped _his_ hands in the same manner, put on an angry look, and passed on. the incident was somewhat curious, as it involved a degree of familiarity with the steward hardly to have been expected. after this we observed a number of queer performances of the steward, and finally comprehended the situation. it seemed that he was afflicted with a peculiar mental or nervous disease, which forced him to imitate everything suddenly presented to his senses. thus, when the captain slapped the paddle-box suddenly in the presence of the steward, the latter instantly gave it a similar thump; or, if any noise were made suddenly, he seemed compelled against his will to imitate it instantly, and with remarkable accuracy. to annoy him, some of the passengers imitated pigs grunting, or called out absurd names; others clapped their hands and shouted, jumped, or threw their hats on the deck suddenly, and the poor steward, suddenly startled, would echo them all precisely, and sometimes several consecutively. frequently he would expostulate, begging people not to startle him, and again would grow furiously angry, but even in the midst of his passion he would helplessly imitate some ridiculous shout or motion directed at him by his pitiless tormenters. frequently he shut himself up in his pantry, which was without windows, and locked the door, but even there he could be heard answering the grunts, shouts, or pounds on the bulkhead outside. he was a man of middle age, fair physique, rather intelligent in facial expression, and without the slightest indication in appearance of his disability. as we descended the bank to go on board the steamer, some one gave a loud shout and threw his cap on the ground; looking about for the steward, for the shout was evidently made for his benefit, we saw him violently throw his cap, with a shout, into a chicken-coop, into which he was about to put the result of his foraging expedition among the houses of the stanitza. [footnote : "observations upon the korean coast, japanese-korean ports, and siberia, made during a journey from the asiatic station to the united states, through siberia to europe, june to september , ." published by the united states navy department, washington, , pp. .] "we afterward witnessed an incident which illustrated the extent of his disability. the captain of the steamer, running up to him, suddenly clapping his hands at the same time, accidentally slipped and fell hard on the deck; without having been touched by the captain, the steward instantly clapped his bands and shouted, and then, in powerless imitation, he too fell as hard and almost precisely in the same manner and position as the captain. in speaking of the steward's disorder, the captain of the general staff stated that it was not uncommon in siberia; that he had seen a number of cases of it, and that it was commonest about yakutsk, where the winter cold is extreme. both sexes were subject to it, but men much less than women. it was known to russians by the name of 'miryachit'". so far as i am aware--and i have looked carefully through several books of travel in siberia--no account of this curious disease has been hitherto published. the description given by the naval officers at once, however, brings to mind the remarks made by the late dr. george m. beard, before the meeting of the american neurological association in , relative to the "jumpers" or "jumping frenchmen" of maine and northern new hampshire.[ ] [footnote : "journal of nervous and mental diseases," vol. vii., , p. .] in june, , dr. beard visited moosehead lake, found the "jumpers," and experimented with them. he ascertained that whatever order was given them was at once obeyed. thus, one of the jumpers who was sitting in a chair with a knife in his hand was told to throw it, and he threw it quickly, so that it stuck in a beam opposite; at the same time he repeated the order to throw it with a cry of alarm not unlike that of hysteria or epilepsy. he also threw away his pipe, which he was filling with tobacco, when he was slapped upon the shoulder. two jumpers standing near each other were told to strike, and they struck each other very forcibly. one jumper, when standing by a window, was suddenly commanded by a person on the other side of the window to jump, and he jumped up half a foot from the floor, repeating the order. when the commands are uttered in a quick, loud voice, the jumper repeats the order. when told to strike he strikes, when told to throw he throws whatever he may happen to have in his hand. dr. beard tried this power of repetition with the first part of the first line of virgil's "Æneid" and the first part of the first line of homer's "iliad," and out-of-the-way words of the english language with which the jumper could not be familiar, and he repeated or echoed the sound of the word as it came to him in a quick, sharp voice, at the same time he jumped, or struck, or threw, or raised his shoulders, or made some other violent muscular motion. they could not help repeating the word or sound that came from the person that ordered them, any more than they could help striking, dropping, throwing, jumping, or starting; all of these phenomena were indeed but parts of the general condition known as jumping. it was not necessary that the sound should come from a human being; any sudden or unexpected noise, as the explosion of a gun or pistol, the falling of a window, or the slamming of a door--provided it was unexpected and loud enough--would cause these jumpers to exhibit some one or all of these phenomena. one of these jumpers came very near cutting his throat, while shaving, on hearing a door slam. they had been known to strike their fists against a red-hot stove, to jump into the fire and into water. they could not help striking their best friend if near them when ordered. the noise of a steam whistle was especially obnoxious to them. one of these jumpers, when taking some bromide of sodium in a tumbler, was told to throw it, and he dashed the tumbler upon the floor. it was dangerous to startle them in any way when they had an ax or an knife in their hands. all of the jumpers agreed that it tired them to be jumped, and they dreaded it, but they were constantly annoyed by their companions. from this description it will at once, i think, be perceived that there are striking analogies between "miryachit" and this disorder of the "jumping frenchmen" of maine. indeed, it appears to me that, if the two affections were carefully studied, it would be found that they were identical, or that, at any rate, the phenomena of the one could readily be developed into those of the others. it is not stated that the subjects of miryachit do what they are told to do. they require an example to reach their brains through the sense of sight or that of hearing, whereas the "jumpers" do not apparently perform an act which is executed before them, but they require a command. it seems, however, that a "jumper" starts whenever any sudden noise reaches his ears. in both classes of cases a suggestion of some kind is required, and then the act takes place independently of the will. there is another analogous condition known by the germans as _schlaftrunkenheit_, and to english and american neurologists as somnolentia, or sleep-drunkenness. in this state an individual, on being suddenly awakened, commits some incongruous act of violence, ofttimes a murder. sometimes this appears to be excited by a dream, but in others no such cause could be discovered. thus, a sentry fell asleep during his watch, and, being suddenly aroused by the officer in command, attacked the latter with his sword, and would have killed him but for the interposition of the bystanders. the result of the medical examination was that the act was involuntary, being the result of a violent confusion of mind consequent upon the sudden awaking from a profound sleep. other cases are cited by wharton and stille in their work on medical jurisprudence, by hoffbauer, and by myself in "sleep and its derangements." the following cases among others have occurred in my own experience: a gentleman was roused one night by his wife, who heard the street-door bell ring. he got up, and, without paying attention to what she said, dragged the sheets off of the bed, tore them hurriedly into strips, and proceeded to tie the pieces together. she finally succeeded in bringing him to himself, when he said he had thought the house was on fire, and he was providing means for their escape. he did not recollect having had any dream of the kind, but was under the impression that the idea had occurred to him at the instant of his awaking. another was suddenly aroused from a sound sleep by the slamming of a window-shutter by the wind. he sprang instantly from his bed, and, seizing a chair that was near, hurled it with all his strength against the window. the noise of the breaking of glass fully awakened him. he explained that he imagined some one was trying to get into the room and had let his pistol fall on the floor, thereby producing the noise which had startled him. in another case a man dreamed that he heard a voice telling him to jump out of the window. he at once arose, threw open the sash, and jumped to the ground below, fortunately only a distance of about ten feet, so that he was not injured beyond receiving a violent shock. such a case as this appears to me to be very similar to those described by dr. beard in all its essential aspects. a few years ago i had a gentleman under my charge who would attempt to execute any order given him while he was asleep by a person whispering into his ear. thus, if told in this way to shout, he shouted as loud as he could; if ordered to get up, he at once jumped from the bed; if directed to repeat certain words, he said them, and so on. i am not able to give any certain explanation of the phenomena of miryachit or of the "jumpers," or of certain of those cases of sleep-drunkenness which seem to be of like character. but they all appear to be due to the fact a motor impulse is excited by perceptions without the necessary concurrence of the volition of the individual to cause the discharge. they are, therefore, analogous to reflex actions, and especially to certain epileptic paroxysms due to reflex irritations. it would seem as though the nerve cells were very much in the condition of a package of dynamite or nitro glycerin, in which a very slight impression is sufficient to effect a discharge of nerve force. they differ, however, from the epileptic paroxysm in the fact that the discharge is consonant with the perception--which is in these cases an irritation--and is hence an apparently logical act, whereas in epilepsy the discharge is more violent, is illogical, and does not cease with the cessation of the irritation. certainly the whole subject is of sufficient importance to demand the careful study of competent observers. * * * * * the gum disease in trees.[ ] [footnote : communicated to the _medical times_ by sir james paget.] an essay by dr. beijerinck, on the contagion of the gum disease in plants, lately published by the royal academy of sciences at amsterdam, contains some useful facts. the gum disease (_gummosis, gum-flux)_ is only too well known to all who grow peaches, apricots, plums, cherries, or other stone fruits. a similar disease produces gum arabic, gum tragacanth, and probably many resins and gum resins. it shows itself openly in the exudation of thick and sticky or hard and dry lumps of gum, which cling on branches of any of these trees where they have been cracked or wounded through the bark. dr. beijerinck was induced to make experimental inoculations of the gum disease by suspicions that, like some others observed in plants, it was due to bacteria. he ascertained that it is in a high degree contagious, and can easily be produced by inserting the gum under the edge of a wound through the bark of any of the trees above named. the observation that heated or long boiled pieces of gum lose their contagious property made it most probable that a living organism was concerned in the contagions; and he then found that only those pieces of the gum conveyed contagion in which, whether with or without bacteria, there were spores of a relatively highly organized fungus, belonging to the class of ascomycetes; and that these spores, inserted by themselves under the bark, produced the same pathological changes as did the pieces of gum. the fungus thus detected, was examined by professor oudemans, who ascertained it to be a new species of coryneum, and has named it _coryneum beijerincki_. the inoculation experiments are best made by means of incisions through the bark of young branches of healthy peach trees or cherry trees, and by slightly raising the cut edge of the bark and putting under it little bits of gum from a diseased tree of the same kind. in nearly every instance these wounds become the seats of acute gum disease, while similar wounds in the same or other branches of the same tree, into which no gum is inserted, remain healthy, unless, by chance, gum be washed into them during rain. the inoculation fails only when the inserted pieces of gum contain no coryneum. by similar inoculations similar diseases can be produced in plum, almond, and apricot trees, and with the gum of any one of these trees any other can be infected; but of many other substances which beijerinck tried, not one produced any similar disease. the inoculation with the gum is commonly followed by the death of more or less of the adjacent structures; first of the bark, then of the wood. small branches or leaf stalks thus infected in winter, or in many places at the same time, may be completely killed; but, in the more instructive experiments the first symptom of the gum disease is the appearance of a beautiful red color around the wound. it comes out in spots like those which often appear spontaneously on the green young branches of peach trees that have the gum disease; and in these spots it is usual to find coryneum stromata or mycelium filaments. the color is due to the formation of a red pigment in one or more of the layers of the cells of the bark. but in its further progress the disease extends beyond the parts at which the coryneum or any structures derived from it can be found; and this extension, beijerinck believes, is due to the production of a fluid of the nature of a ferment, produced by the coryneum, and penetrating the adjacent structures. this, acting on the cell walls, the starch granules, and other constituents of the cells, transforms them into gum, and even changes into gum the coryneum itself, reminding the observer of the self-digestion of a stomach. in the cells of the cambium, the same fluid penetrating unites with the protoplasm, and so alters it that the cells produced from it form, not good normal wood, but a morbid parenchymatous structure. the cells of this parenchyma, well known among the features of gum disease, are cubical or polyhedral, thin walled, and rich in protoplasm. this, in its turn, is transformed into gum, such as fills the gum channels and other cavities found in wood, and sometimes regarded as gum glands. and from this also the new ferment fluid constantly produced, and tracking along the tissues of the branches, conveys the coryneum infection beyond the places in which its mycelium can be found. * * * * * drinkstone park. drinkstone has long been distinguished on account of the successful cultivation of remarkable plants. it lies some eight miles southeast from bury st. edmund's, and is the seat of t.h. powell, esq. the mansion or hall is a large old-fashioned edifice, a large portion of its south front being covered by a magnificent specimen of the magnolia grandiflora, not less than feet in height, while other portions of its walls are covered with the finest varieties of climbing roses and other suitable plants. the surrounding country, although somewhat flat, is well wooded, and the soil is a rich loam upon a substratum of gravel, and is consequently admirably suited to the development of the finer kinds of coniferous and other ornamental trees and shrubs, so that the park and grounds contain a fine and well selected assortment of such plants. [illustration: the snowflake, leucojum vernum, at drinkstone park.] coniferous trees are sometimes considered as out of place in park scenery; this, however, does not hold good at drinkstone, where mr. powell has been displayed excellent taste in the way of improving the landscape and creating a really charming effect by so skillfully blending the dressed grounds with the rich greensward of the park that it is not easy to tell where the one terminates or the other commences. the park, which covers some acres, including a fine lake over eight acres in extent, contains also various large groups or clumps of such species as the sequoia gigantea, taxodium sempervirens, cedres deodora, picea douglasii, pinsapo, etc., interspersed with groups of ornamental deciduous trees, producing a warm and very pleasing effect at all seasons of the year. among species which are conspicuous in the grounds are fine, well-grown examples of araucaria imbricata, some feet high; cedrus deodara, feet in height; abies pinsapo, feet; and fine specimens of abies grandis, a. nobilis, and a. nordmanniana, etc., together with abies albertiana or mertensiana, a fine, free-growing species; also libocedrus gigantea, thuiopsis borealis, thuia lobbii, juniperus recurva, taxas adpressa, fine plants; with fine golden yews and equally fine examples of the various kinds of variegated hollies, etc. [illustration: odontoglossum rossi major var. rubescens, at drinkstone park.] particular attention is here paid to early spring flowers. drinkstone is also celebrated as a fruit growing establishment, more particularly as regards the grape vine; the weight and quality of the crops of grapes which are annually produced here are very remarkable.--_the gardeners' chronicle._ * * * * * on the changes which take place in the conversion of hay into ensilage. by fredk. jas. lloyd, f.c.s., lecturer on agriculture, king's college. the recently published number of the _royal agricultural society's journal_ contains some information upon the subject of silage which appears to me of considerable interest to those chemists who are at present investigating the changes which take place in the conversion of grass into silage. the data[ ] are, so far as i know, unique, and though the analytical work is not my own, yet it is that of an agricultural chemist, mr. a. smetham, of liverpool, whose work i know from personal experience to be thoroughly careful and reliable. i have therefore no hesitation in basing my remarks upon it. [footnote : _royal agricultural society's journal_, vol. xx., part i., pp. and .] we have here for the first time an accurate account of the quantity of grass put into a silo, of the quantity of silage taken out, and of the exact composition both of the grass and resulting silage. i desire merely to place myself in the position of, so to speak, a "chemical accountant." the ensilage has been analyzed at three depths, or rather in three layers, the first being foot, the second ft. to ft. in., and the third ft. in. to ft. from the bottom of the silo. by doubling the figures of the bottom layer analysis, adding these to the second and third layer analysis, and dividing by , we obtain a fair representation of the average composition of the silage taken throughout the silo, for by so doing we obtain the average of the analyses of each -inch layer of silage. the results of the analyses are as follows, calculated on the dry matter. the moisture was practically the same, being . per cent, in the grass and . in the silage. _composition of grass and silage (dried at °c.)._ grass. ensilage. fat (ether extract) . . soluble albuminous compounds . . insoluble albuminous compounds . . mucilage, sugar, and extractives, etc. . . digestible fiber . . indigestible woody fiber . . ------- ------- . . soluble mineral matters . . insoluble mineral matters . . ------- ------- . . the striking difference in the mineral matter of the grass and silage i will merely draw attention to; it is not due to the salt added to the silage. i may say, however, that other analysts and i myself have found similar striking differences. for instance, prof. kinch[ ] found in grass . per cent. mineral matter, in silage . per cent., which, as be points out, is equivalent, to a "loss of about per cent. of combustible constituents"--a loss which we have no proof of having taken place. in mr. smetham's sample the loss would have to be per cent., which did not occur, and in fact is not possible. what is the explanation? [footnote : _journ. chem. society_, march, , p. .] i am, however, considering now the organic constituents. calculating the percentages of these in the grass and silage, we obtain the following figures: _percentage composition of organic compounds._ grass. ensilage. fat (ether extract) . . soluble albuminous compounds . } { . } . . { insoluble " " . } { . mucilage, sugar, and extractives . . digestible fiber . . indigestible woody fiber . . ------- ------- . . the difference in the total nitrogen in the grass and silage is equal to . per cent. of albuminoids. practically it is a matter of impossibility that the nitrogen could have increased in the silo, and it will be a very safe premise upon which to base any further calculations that the total amount of nitrogen in the silage was identical with that in the grass. there may have been a loss, but that is not yet proved. arguing then upon the first hypothesis, it is evident that parts of the organic matters of silage represent more than parts of the organic matter of grass, and by the equation we obtain . : . :: : approximately. if now we calculate the composition of parts organic matter of grass, it will represent exactly the organic matter which has gone to form parts of that present in silage. the following table gives these results, and also the loss or gain in the various constitutents arising from the conversion into silage: _organic matter_. in pts. in pts. loss or grass. silage. gain. fat (ether extract) . . + . soluble albuminous compounds . . + . insoluble " " . . - . mucilage . . - . digestible fiber . . - . indigestible woody fiber . . + . ------- ------- . . these calculations show, provided my reasoning be correct, that the chief changes which take place are in the albuminous compounds, which has already been pointed out by professors voelcker, kinch, and others; and in the starch, gum, mucilage, sugar, and those numerous bodies termed extractives, which was to be expected. but they show most conclusively that the "decrease in the amount of indigestible fiber and increase in digestible" so much spoken of is, so far as our present very imperfect methods of analyzing these compounds permit us to judge, a myth; and i have not yet found any sufficient evidence to support this statement. a loss, then, of parts of organic matter out of every parts put into the silo has in this instance taken place, due chiefly to the decomposition of starch, sugar, and mucilage, etc. and as the grass contained parts of water when put into the silo, the total loss would only be . per cent. of the total weight. this theoretical deduction was found by practical experience correct, for mr. smith, agent to lord egerton, upon whose estate this silage was made, in his report to mr. jenkins says the "actual weight out of the silo corresponds exactly with the weight we put into the same." in my judgment these figures are of interest to the agricultural chemist for many reasons. first, they will clear the ground for future workers and eliminate from their researches what would have greatly complicated them--changes in the cellulose bodies. secondly, they are of interest because our present methods of distinguishing between and estimating digestible and indigestible fiber is most rough, and probably inaccurate, and may not in the least represent the power of an animal--say a cow--to digest these various substances; and most of us know that when a new method of analysis becomes a necessity, a new method is generally discovered. lastly, they are of interest to the agriculturist, for they point out, i believe for the first time, the exact amount of loss which grass--or at least one sample--has undergone in conversion into silage, and also that much of the nitrogenous matter is changed, and so far as we know at present, lost its nutritive value. this, however, is only comparing silage with grass. what is wanted is to compare silage with hay--both made out of the same grass. then, and then only, will it be possible to sum up the relative advantages or disadvantages of the two methods of preserving grass as food for cattle.--_chem. news_. * * * * * the illuminating power of ethylene. dr. percy frankland has obtained results which may be thus briefly summarized: ( .) that pure ethylene, when burnt at the rate of cubic feet per hour from a referee's argand burner, emits a light of . standard candles. ( .) that the illuminating power of equal volumes of mixtures of ethylene with either hydrogen carbonic oxide or marsh-gas is less than that of pure ethylene. ( .) that when the proportion of ethylene in such mixtures is above per cent. the illuminating power of the mixture is but slightly affected by the nature of the diluent. when, on the other hand, the proportion of ethylene in such mixtures is low, the illuminating power of the mixture is considerably the highest when marsh-gas is the diluent, and the lowest when the ethylene is mixed with carbonic oxide. ( .) that if cubic feet of ethylene be uniformly consumed irrespectively of the composition of the mixture, the calculated illuminating power is in every case equal to or actually greater than that of pure ethylene until a certain degree of dilution is attained. this intrinsic luminosity of ethylene remains almost constant when the latter is diluted with carbonic oxide, until the ethylene forms only per cent. of the mixture, after which it rapidly diminishes to zero when the ethylene forms only per cent. of the mixture. when the ethylene is diluted with hydrogen, its intrinsic luminosity rises to candles when the ethylene constitutes per cent. of the mixture, after which it rapidly falls to zero when the ethylene amounts to only per cent. in the case of mixtures of ethylene and marsh-gas, the intrinsic luminosity of the former is augmented with increasing rapidity as the proportion of marsh gas rises, the intrinsic luminosity of ethylene, in a mixture containing per cent. of the latter, being between and candles. * * * * * diffraction phenomena during total solar eclipses.[ ] [footnote : a paper read before the american astronomical society, may , .] by g.d. hiscox. the reality of the sun's corona having been cast in doubt by a leading observer of the last total eclipse, who, from the erratic display observed in the spectroscope, has declared it a subjective phenomenon of diffraction, has led me to an examination and inquiry as to the bearing of an obscurely considered and heretofore only casually observed phenomenon seen to take place during total solar eclipses. this phenomenon, it seems to me, ought to account for, and will possibly satisfy, the spectroscopic conditions observed just before, during, and after totality; which has probably led to the epithet used by some leading observers--"the fickle corona." the peculiar phenomenon observed in the spectroscope, the flickering bands or lines of the solar spectrum flashing upon and across the coronal spectrum, has caused no little speculation among observers. the diffraction or interference bands projected by the passage of a strong beam of light by a solid body, as discovered long since by grimaldi, and investigated later by newton, fresnel, and fraunhofer, are explained and illustrated in our text books; but the grand display of this phenomenon in a total solar eclipse, where the sun is the source of light and the moon the intercepting body, has as yet received but little attention from observers, and is not mentioned to my knowledge in our text books. in the instructions issued from the united states naval observatory and the signal office at washington for the observation of the eclipse of july , , attention was casually directed to this phenomenon, and a few of the observers at pike's peak, central city, denver, and other places have given lucid and interesting descriptions of the flight of the diffraction bands as seen coursing over the face of the earth at the speed of the moon's shadow, at the apparent enormous velocity of thirty-three miles per minute, or fifty times the speed of a fast railway train. from a known optical illusion derived from interference or fits of perception, as illustrated in quick moving shadows, this great speed was not realized to the eye, as the observed motion of these shadows was apparently far less rapid than their reality. the ultra or diffraction bands outside of the shadow were distinctly seen and described by mr. j.e. keeler at central city, both before and after totality. he estimates the shadow bands at inches wide and feet apart. professor e.s. holden, also at central city, estimated the dark bands as about feet apart, and variable. from estimates which he obtained from other observers of his party, the distances between the bands varied from to l½ feet, but so quickly did they pass that they baffled all attempts to count even the number that passed in one second. he observed the time of continuance of their passage from west to east as forty-eight seconds, which indicates a width of miles of diffraction bands stretching outward from the edge of the shadow to the number of many thousands. mr. g.w. hill, at denver, a little to the north of the central track of the shadow, observed the infra or bands within the shadow, alluding to the fact that they must be moving at the same rate as the shadow, although their apparent motion was much slower, or like the shadows of flying clouds. he attributes the discrepancy to optical illusion. at virginia city the _colors_ of the _ultra_ bands were observed, and estimated at five seconds' duration from the edge of the shadow, which is equal to about miles in width. these are known to be the strongest color bands in the diffraction spectrum, which accounts for their being generally observed. mr. w.h. bush, observing at central city, in a communication to prof. holden alludes to the brilliancy of the colors of these bands as seen through small clouds floating near the sun's place during totality, and of the rapid change of their rainbow colors as observed dashing across the clouds with the rapidity of thought. all of these bands, both ultra and infra, as seen in optical experiments, are colored in reverse order, being from violet to red for each band outward and inward from the edge of the shadow. it is very probable that the velocity of the passage of all the bands during a total eclipse very much modifies the distinctness of the colors or possibly obliterates them by optically blending so as to produce the dull white and black bands which occupied so large a portion of this grand panorama. the phenomenon of these faint colored bands, with the observed light and dark shadows, may be attributed to one or all of the following causes: . a change in the direction of a small portion of the sun's light passing by the solid body of the moon, it being deflected outward by repulsion or reflection from its surface, and other portions being deflected inward after passing the body by mutual repulsion of its own elements toward a _light vacuum_ or space devoid of the element of vibration. . the colored spectral bands being the direct result of the property of interference, or the want of correspondence of the wave lengths due to divergence; the same phenomenon being also observed in convergent light. this is practically illustrated in the hazy definition of the reduced aperture of telescopes, and its peculiarities shown in the spectral rings within and beyond the focus. . chromatic dispersion by our atmosphere, together with selective absorption, also by our atmosphere and its vapors, have been suggested as causes in this curious and complicated phenomena. in none of the reports descriptive of the phenomena of polarization of the corona is there the slightest allusion to the influence that the diffraction bands may possibly have in modifying or producing the various conditions of polarization observed; although these observations have been made and commented upon during the past twenty-five years. investigations now in progress of the modifying relation of the phenomenon of diffraction in its effect upon not only the physical aspect of the corona, but also in some strange spectroscopic anomalies that have been observed near the sun at other times than during a total solar eclipse, will, it is hoped, result in a fuller interpretation of the physical nature of one of the grandest elements of creation--_light_; let there be more of it. * * * * * a catalogue containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . , stitched in paper, or $ . , bound in stiff covers. combined rates--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn &. co., publishers, broadway, new york, n.y. * * * * * patents. in connection with the scientific american, messrs munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats, trade marks, their costs, and how procured. address munn & co., broadway, new york. branch office, cor. f and th sts., washington. d.c. * * * * * +--------------------------------------------------------------+ | transcriber's note: | | | | this children's book has a new paragraph for every sentence, | | and other unusual formatting. | | | | inconsistent hyphenation and quotation marks in the original | | document have been preserved. | | | | a number of obvious typographical errors have been corrected | | in this text. for a complete list, please see the end of | | this document. | | | +--------------------------------------------------------------+ * * * * * _young folk's library of choice literature_ stories of great inventors fulton whitney morse cooper edison by hattie e. macomber educational publishing company boston new york chicago san francisco copyrighted by educational publishing company contents. page robert fulton eli whitney samuel morse peter cooper thomas a. edison [illustration: fulton.] robert fulton. this story is about a giant. do you believe in them? he peeps out of your coffee cup in the morning. he cheers you upon a cold day in winter. but the boys and girls were not so well acquainted with him a hundred years ago. about that long ago, far to the north and east, a queer boy lived. he sat in his grandmother's kitchen many an hour, watching the tea-kettle. he seemed to be idle. but he was really very busy. he was talking very earnestly to the giant. the giant was a prisoner. no one knew how to free him. many had often tried to do this and failed. he was almost always invisible. but when he did appear, it was in the form of a very old man. this old man had long, white hair, and a beard which seemed to enwrap him like a cloak--a cloak as white as snow. so his name is the white giant. the boy's name was james watt. he lived in far-away scotland. he sat long, listening to the white giant as he told him many wonderful things. the way in which the giant first showed himself to james was very strange. james noticed that the lid of the tea-kettle was acting very strangely. it rose and fell, fluttered and danced. now, james had lived all his life among people who believed in witches and fairies. so he was watching for them. and he thought there was somebody in the kettle trying to get out. so he said, "who are you and what do you want?" "space, freedom, and something to do," cried the giant. "if you will only let me out, i'll work hard for you. i'll draw your carriages and ships. i'll lift all your weights. i'll turn all the wheels of your factories. i'll be your servant always, in a thousand other ways." [illustration: john fitch's steamboat, . by permission of providence & stonington steamship co.] if you have now guessed the common name of this giant, we will call him steam. at the time james watt lived, there were no steam boats, steam mills, nor railways. and this boy, though his grandmother scolded, thought much about the giant in the tea-kettle. and he became the inventor of the first steam engine that was of any use to the world. so, little by little, people came to know that steam is a great, good giant. they tried in many different ways to make him useful. they wished very much to make him run a boat. one man tried to run his boat in a queer way. he made something like a duck's foot to push it through the water. another moved his boat by forcing a stream of water in at the bow and out at the stern. then came a man named john fitch. he made his engine run a number of oars so as to paddle the boat forward. he grew very poor. people laughed at him. but he said, "when i shall be forgotten, steam boats will run up the rivers and across the seas." then people laughed the harder and called him "a crank." mr. fitch's boat was tried in . now, in , there happened a good thing for this old world. a little baby boy was born in that year. perhaps you wonder why it was such a good thing for the world. some of you will know why when you read that this baby's name was robert fulton. his father was poor. his father was a farmer in pennsylvania. mr. fulton had two little girls older than baby robert. when robert was grown larger he had three sisters and one brother. but their father died when they were all small. robert did not go to school till he was eight years old. his mother taught him at home. he knew how to read and write, and a very little arithmetic. his first teacher was a mr. johnson. mr. johnson was a quaker. he thought robert a dull pupil. robert did not learn his lessons very well. but mr. johnson soon found that he was never idle. he did not care to play at recess. he stayed in and used his pencil in drawing. he often spent hours in this way. robert soon became fond of going into the machine shops. he understood machinery very quickly. the men always gave him a welcome. he didn't get into mischief. he often helped the men with his neat drawings. one day robert was late in getting to school. the master asked the reason. robert answered that he had been in mr. miller's shop pounding out lead for a lead pencil. mr. johnson then encouraged him in doing such useful things. in a few days, all the pupils in the school had pencils made in that way. mr. johnson urged robert to give more attention to his studies. robert said, "my head is so full of thoughts of my own that i haven't room there for the thoughts from dusty books." as he was not idle, no doubt this was true. when robert was thirteen, the boys in the town had a great disappointment. it was nearly july. of course the boys expected to celebrate the fourth. but a notice was put up. this notice urged the people not to illuminate their homes. it was very warm weather. the people then had only candles with which to light their homes. candles were very scarce. but robert had some. he took them to a shop and exchanged them for powder. the owner of the store asked him why he gave up the candles, which were so scarce and dear. robert said, "i am a good citizen, and if our officers do not wish us to illuminate the town, i shall respect their wishes." he found some pieces of paste-board. he rolled these himself. in this way he made some rockets. the store-keeper told him he would find it impossible to do this. "no, sir," robert answered, "there is nothing impossible." his rockets were a success, and the people were astonished. robert bought at different times small quantities of quicksilver. the men in the machine shops were curious to know what he did with it. but they could not find out. for this reason they called him "quicksilver bob." robert was interested in guns. sometimes he would tell the workmen how to improve them. the men liked him so well that they were always willing to try whatever he advised. robert was fond of fishing. one of the workmen often went fishing with his father. this man sometimes took robert. they had only an old flat boat. the boys had to pole the boat from place to place. it was hard work. they were sometimes very tired. robert, soon after one fishing excursion, went away to visit an aunt. he was gone a week. while away he made a complete model of a little fishing boat. this boat had paddle wheels. the model was placed in the garret. many years afterward his aunt was proud to have it as an ornament on her parlor table. of course the boys arranged a set of paddle wheels for their fishing boat. after this they enjoyed their fishing much more than before. robert fulton's boyhood was during the revolutionary war. he made many queer pictures of the hessian soldiers. these hessians were germans, who had been hired by the british to help them fight the americans. the people who wished our country to belong to england were called tories. those who wished america to be free were called whigs. the whig boys often fought the tory boys on the soldiers' camp ground. the soldiers grew tired of this. they stretched a rope to keep the boys out. robert drew a picture in which the whigs crossed the rope and whipped the tories. the boys all thought it a good picture. so they tried to make it real. they became so troublesome that the town officers had to interfere. but robert was all this time fast growing up. he had to choose some way of taking care of himself. he was more fond of his pencil and brush than of anything else. near his home, had lived a celebrated painter. his name was benjamin west. benjamin west's father and robert's father had been great friends. mr. west had become famous. he now lived in england. robert thought he would like to be an artist, too. so he left his home and went to the city of philadelphia. he knew that it meant hard work. he was industrious and pains-taking. he had many friends. benjamin franklin was one of his friends. soon he did very nice work. in the four years after he was seventeen, he not only took care of himself, but sent money to his mother and sisters. he spent his twenty-first birthday at home. he had then earned enough money to buy a small farm for his mother. for this farm he paid four hundred dollars. he helped his family to get nicely settled in their new home. then he went back to philadelphia. at this time mr. fulton, as we must now call him, was not well. partly for this reason he decided to take a voyage to europe. he carried letters from many well-known americans. he found friends in europe. benjamin west was kind to him there. [illustration: a canal scene.] he soon had plenty of work to do. one of his friends was an english gentleman, who was called the earl of stanhope. the earl was much interested in canals. canals, you probably know, are artificial rivers. boats are drawn on them by horses, which walk along a path on the shore. the path is called the tow-path. railways were almost unknown then. so canals were very useful in carrying goods across the country. they had been in use in europe and asia for hundreds of years. mr. fulton invented a double inclined-plane. this could be used in raising and lowering canal boats without disturbing their cargoes. the british government gave mr. fulton a patent upon it. mr. fulton wrote a book about canals and the ways in which they help a country. he sent copies of this book to the president of the united states, and other men in high offices. he thought canals would help america. but it was ten years before he could get people to think much about it. then mr. fulton helped in planning the erie canal. this was very successful. you can see this canal now. it is in the state of new york and is still used. mr. fulton planned a cast-iron aqueduct which was built in scotland. an aqueduct is often made to carry water to cities. he invented a mill for sawing marble, a machine for spinning flax, another for scooping out earth, called a dredging machine, and several kinds of canal boats. you will wonder before reaching the end of this story how one man could do so many things. but you must remember that he was never lazy as a boy, and so learned to make good use of every moment. in , mr. fulton went to the greatest city in france, called paris. there he made a new friend. this was joel barlow, an american and a poet. mr. fulton thought that all ships should have the freedom of the ocean. he thought it would take hundreds of years to get all nations to consent to this. he believed that he could find a quicker way. he thought it would be best to blow up all warships. he made a little sub-marine boat. sub-marine means under the sea. this boat could be lowered below the surface of the water. he found a way to supply it with air. but he could not get it to run swiftly. it took much money to build such boats. he tried to get the french government to help him. he was often tired and disappointed. but he never stopped trying. he tried to destroy some large boats. this was to be done with torpedoes. but he was not very successful. he succeeded in destroying one boat. but since then others have carried out his plan, and torpedoes are often used in war. this little story is told of mr. fulton:-- he was once in new york working upon his torpedoes. he invited the mayor and many others to hear him lecture. they came and were all much interested. he showed them the copper cylinders which were to hold the powder. then he showed them the clockwork, which, when it was set running, would cause the cylinders to explode. he turned to a case and drew out a peg. he then said, "gentlemen, this torpedo is all ready to blow up a vessel. it contains one hundred and seventy pounds of powder. the clockwork is now running. if i should allow it to run fifteen minutes it would blow us all to atoms." his audience was much frightened. they all ran away. mr. fulton put the peg back in its place. he told them it was then safe. not until then did they dare come back. but now our giant, steam, became the friend of mr. fulton. many had tried to put this giant to work. but at first he seemed rather hard to teach. long before, a poet had written these lines, which show how much people hoped to make the giant do:-- "soon shall thy arm, unconquered steam, afar drag the slow barge, or drive the rapid car." it was a true prophecy. mr. fulton married the daughter of a mr. walter livingston. this mr. livingston had a relative who was a great man, and a rich man. he was much interested in all inventions. he often helped inventors with his money. he had long believed that boats could be moved by steam. at one time the state of new york gave him the right of all steam boats for twenty years. he was given the right if he would get one steam boat running within a year. but the year passed and the boat was not built. everybody made fun of his "grand rights." at this time our government made him our minister to france. there he met robert fulton for the first time. and in paris mr. livingston and mr. fulton made a steam boat. when it was finished they invited their friends to come and see it tried. early upon the morning when they hoped to succeed, a messenger came. he bore sad news. the new boat had broken in two. the machinery was too heavy for it. it had sunk to the bottom of the river seine. mr. fulton had not had his breakfast. he hurried to the river. he worked standing in the cold water. in twenty-four hours he had saved the machinery, and some other parts of the boat. but it made him ill. he never was so strong again. of course he felt greatly discouraged. they went to work again. they built another boat. this was a success. it was sixty-six feet long, and moved by wheels on the side. mr. livingston and mr. fulton decided to try again in america upon the hudson river. mr. livingston was given again the same privileges by the state of new york. but this time mr. fulton was his partner. they were given two years in which to make their boat. they were to make one which could go four miles an hour. it took much money. mr. fulton promised to ask only a certain sum of mr. livingston. but this sum proved to be too small. he went to see a friend. he talked long and earnestly to him. but the friend grew tired and told him he must go home or go to bed. mr. fulton wanted one thousand dollars. his friend said he would see him again. [illustration: the eructor amphibolis. a combined steamboat and locomotive constructed by oliver evans a native of newport, delaware, in .] [illustration: perspective view of machinery in fulton's clermont. by permission of providence & stonington steamship co.] mr. fulton came again before the poor man had had any breakfast. he gave him no peace. but he got his money at last. mr. fulton was much laughed at for trying to make such a boat. the boat was called by people, "fulton's folly." his friends would listen politely to him. but he said he knew they did not believe in him. he often, as he walked about, heard people laugh and sneer at him. but at last the boat was done. the sun rose smiling on that august morning. the world was enjoying its morning nap. only a few people were on the shores. gracefully the boat was moved from the jersey shore. [illustration: the clermont, by permission of providence & stonington steamship co.] those who saw were amazed. old sailors were frightened. when they saw a boat with no sails, they thought it an evil spirit. but the long line of black smoke which they saw was only the breath of the dear old giant, steam. at last he had something to do. this boat was called the clermont. it passed the city of new york. it passed the beautiful highlands of the hudson. it puffed patiently on until it reached albany. all along the shores people watched it breathlessly. everybody stopped sneering and cheered. the clermont had gone one hundred and fifty miles in thirty-two hours. except that the ocean steamships are larger, handsomer, and more finely finished, they are much like mr. fulton's clermont. who can doubt mr. fulton's joy at his success. at last he had found a way to make all nations know each other. mr. fulton had other troubles after this. wicked people tried to steal his invention from him. but no one else has ever been given credit for it. everyone who tried a ride upon the boat found it much nicer than jolting along in a stage coach. in two years a regular line of boats was running between the great city of new york and its capital city. mr. fulton built other boats. some of them were ferry-boats. [illustration: brooklyn bridge and fulton ferry.] a ferry from new york to long island is still called by his name, fulton ferry. do you suppose the thousands of people who cross by it, ever think of patient, industrious, hard-working, robert fulton? in january, , mr. fulton went to trenton, new jersey, as witness in a lawsuit. the weather was very severe. mr. fulton became much chilled. in coming back his boat was caught in the ice. it was several hours before it could be moved. you remember mr. fulton was not very strong. he was ill for several days. he was very anxious about a boat which he was building. he left his bed too soon. he was then taken very ill indeed. and upon the twenty-fourth of february, , the world lost this great man. everyone mourned his loss. the great city of new york was in mourning. he was buried in the livingston vault in trinity churchyard, new york. no monument has ever been raised over this great man. but the boats which every year ply back and forth upon lake, river, and ocean, are constant reminders of his great work for the world. [illustration: eli whitney.] eli whitney. the war, called the revolution, was ended. the treaty of peace had been signed. america had won her freedom. our country then was smaller than now. it contained only about four million people. these people were widely scattered. the world did not think of the united states as an important country. it was thought to be about as important as denmark or portugal is now. we call one part of our country the south. the south of this time was very different from the south of to-day. fewer cities were to be seen. many forests covered the land. the plantations were few. plantation is the southern word for farm. there were not many slaves then. people hoped slavery would die out. they thought it might if it were let alone. many people left the south to find other homes. this was because they could not make a good living there. indigo, rice, and cotton were raised. but only a little cotton was planted. this was because it was such hard work to get it ready to sell. cotton grows upon a small shrub. people of olden times called it the "wool of trees." the germans still call it "tree-wool." one kind is called "sea-island" cotton. this is because it grows well upon the low, sandy islands of the sea. some such islands are found near south carolina. this cotton likes the salt which it finds in the soil. the herb cotton grows to a height of from eighteen to twenty-four inches. the land is made ready for the seed during the winter. as soon as the frost is gone mother earth is given her baby seeds to care for. soon the beautiful plantlets appear. the leaves are of a dark green. then later come the pale yellow flowers. the plants must then be well cared for. toward autumn the fruit is seen. this looks like a walnut still in its rough coat. [illustration: cotton balls.] then the pods burst. the field is then beautiful. it looks as if it were covered with snow. then comes the hard work of the picking. all hands upon the plantation must then work in the fields. the slaves of long ago were kept very busy during this season. the women and children worked. they have to be careful that the cotton is quite dry when picked. if it were damp the cotton would mould. this would spoil it for use. can you imagine a snow-white field dotted with black people? their bright eyes must have shone still more brightly there. the cotton does not all ripen at one time. but it must be gathered soon after the pods are burst. [illustration] this is because the sun injures the color of the cotton. or the rain and dews injure it. or the winds may blow it away. so the cotton pickers were kept busy from august until the frost came. they went over the same fields many times. then, after a busy day in the field, other work remained to be done. the cotton pickers sat upon the ground in a circle. from the midst of the cotton they took the black seeds. these seeds were very troublesome. they are covered with hairs. they cling fast to the cotton. these naughty children of the plant love their mother. so fast do they cling to her, that a person could clean but one pound of cotton in a whole day. so you may understand why so little was raised. in , eight bags of cotton were taken from the united states to england. these were seized by the custom officers. these officers are those who look after goods sent in or out of a country. if money is to be paid upon the goods, it is called a duty. the custom officers must see that the duty is paid. these men said that this cotton could not have come from america. during the next two years less than one hundred-twenty bags were sent there from our country. the treaty of peace with england was made in . none of the treaty-makers then knew that any cotton was raised in america. would you like to know why, fifty years later, a million bales were sent from america? this is the story: in the war with england, america had some brave generals. one of these was general nathaniel greene. he had helped to win victories in the south. the state of georgia gave him a tract of land. general greene lived with his family upon this land. he at last died there. mrs. greene was very lonely. she went to the north to visit her friends. on her voyage home she met a pleasant gentleman. he was a young man, only twenty-seven years of age. he, too, was going to georgia. his name was eli whitney. and now you must know something of his story. eli whitney was born in massachusetts in . his people were farmers. they were not rich people. eli's father had a workshop. in this shop he worked upon rainy days. he made wheels and chairs. eli grew up like other farm boys. he helped on the farm. he attended the district school. he took care of the cattle and horses. but very early in his life he became fond of tools. he used to creep into his father's shop. he could scarcely wait to be old enough to use the tools there. one of the interesting tools was a lathe for turning chair posts. his father allowed him the use of all these as soon as he was large enough to take care of them. after that, he was always at work at something. he liked work in the shop much more than work upon the farm. eli's mother died when he was a little boy. this is a sad event in any boy's life. when eli was about twelve years old, his father took a journey from home. he was gone two or three days. when he returned, he called the housekeeper. he asked her what the boys had been doing. she told him what the elder boys had done. "but what has eli been doing?" said he. "he has been making a fiddle," was the answer. "ah!" said the father, "i fear eli will take his portion in fiddles." the fiddle was finished like a common violin. it made pretty good music. many people came to see it. they said it was a fine piece of work for a boy. afterwards people brought him their violins to mend. he did the mending nicely. every one was surprised. they brought him other work to do. eli's father had a nice watch. eli loved to look at it. it was a great wonder to him. he wished to see the inside of it. his father would not allow this. one sunday the family were getting ready for church. eli noticed that his father intended leaving his watch at home. he could not lose such a good chance. so he pretended to be quite sick. his father allowed him to stay at home. soon he was alone with the wonderful little watch. he hurried to the room where it hung. he took it down carefully. his hands shook, but he managed to open it. how delightful was the motion of those wheels! it seemed a living thing. eli forgot his father. he thought only of the wonderful machinery. he must know just how it went. he took the watch all to pieces before he remembered how wrong it was to do so. then he began to be frightened. what if he couldn't put it together! he knew his father was a very stern man. slowly and carefully the boy went to work. and so bright was he that he succeeded in getting it together all right. his father did not find out the mischief. several years afterward eli told him about it. when eli was thirteen years old his father married a second time. eli's stepmother had a handsome set of table knives. she valued them highly. one day eli said, "i could make as good knives as those if i had tools. "and i could make the tools if i had common tools to begin with." his mother laughed at him. but soon after one of the knives was broken. eli made a blade exactly like the broken one, except its stamp. soon eli was fifteen years of age. he wished to go into the nail-making business. it was during the revolution. nails were made almost entirely by hand. they were in great demand. they brought good prices. eli asked his father to bring him a few tools. his father consented. the work was begun. eli was very industrious. he made good nails. he also found time to make more tools for his own use. he put in knife blades. he repaired broken machinery. he did many other things beyond the skill of country workmen. eli worked in this way two winters. he made money. he worked on the farm in the summer. at one time eli took a journey of forty miles. he visited every workshop on the way. these visits taught him much. he found a man who could go back with him and help him in his business. at the close of the war it did not pay to go on with the nail-making. the ladies began a new fashion about that time. this was the use of long pins for fastening on their bonnets. he made very nearly all the pins used. eli made these pins with great skill. this work was done in the time spared from his farm work. he also made excellent walking canes. during all these years eli's schooling had been received at different times at the district school. he was very fond of arithmetic. during his nineteenth year he made up his mind to have a college education. his step-mother did not wish him to do this. but he worked hard and saved his money. a part of the time he taught school. he was twenty-three when he entered yale college. he borrowed some money, for which he gave his note. at one time one of the college teachers wished to show his pupils some experiments. but some of the things to be used were broken. eli offered to mend them. this he did, and succeeded in surprising every one. a carpenter lived near his boarding place. eli asked for the loan of some of his tools. the careful carpenter did not wish to lend them. he at last gave his consent in this way:-- the gentleman with whom mr. whitney boarded must promise to pay all the damages. but he soon saw how skilful mr. whitney was. he was surprised and said: "there was one good mechanic spoiled when you went to college." mr. whitney graduated in . he was engaged by a gentleman in georgia to teach his children. it was on this journey to his new work that he met mrs. greene. mrs. greene liked mr. whitney very much. when they reached savannah, she invited him to her home. at this time he had a great disappointment. the gentleman who had hired him to come to georgia coolly told him his services were not wanted. he had no friends. he was out of money. but mrs. greene became his good friend. he went to live at her house. here he began the study of law. mrs. greene was one day doing some embroidery. she broke the frame upon which she was working. she did not know how to finish the work without it. mr. whitney looked at it carefully. then he made her a new frame. it was even better than the other one had been. of course mrs. greene was much pleased. mr. whitney also made fine toys for the children. soon after this, a party of gentlemen visited at mrs. greene's home. they were nearly all men who had been officers during the war. mr. greene had been their general. they began talking of the south. they wished something might be done to improve that part of the country. they wished it might be made a better place in which to live. they spoke of the fine spinning machines that were coming into use in england. much land in the south could be used for cotton. this could be sent to england for manufacture. the south could become a rich country in this way. but there was one great difficulty. it cost so much to clean the cotton. mrs. greene said, "i know who can help you. "apply to my young friend, mr. whitney. he can make anything." she then showed the gentlemen her frame and other things which mr. whitney had made. mr. whitney said he had never seen cotton or its seed. none was raised near the home of the greene's. mr. whitney did not make any promises. but the next day he went to work. he went first to the city of savannah. there he searched among the warehouses and boats. at last he found a small parcel of cotton. this he carried home. he shut himself up in a small basement room. his tools were poor. he made better ones. no wire could be bought in savannah. so he made his own wire. mrs. greene and a mr. miller were the only persons allowed to come into his work-shop. day after day the children wondered to hear the queer clinking and hammering. they laughed at mr. whitney. but that did not trouble him. before the end of the winter the machine was nearly perfect. its success seemed certain. mrs. greene was very happy over the work. she was eager that people should know about this wonderful invention. she could not wait until a patent was secured. a patent is given by the government. it is given to prevent others from claiming an invention. often it keeps people from manufacturing the article without the permission of the owner. so mrs. green invited a party of gentlemen from all parts of the state to visit her. these gentlemen were taken to see the machine do its work. they were greatly astonished. for what did they see? this curious little machine cleaned the cotton of its seed. and it would clean in a day more than a man could do in months. they went to their homes. they told everybody about it. great crowds began coming to see it. but they were refused permission to do so. this was because it had not yet been patented. so one night some wicked men broke into the building. they stole the cotton-gin. you can well imagine how dreadful this was. mr. whitney had no money. so mr. miller agreed to be his partner. mr. miller had come to georgia from the north. he, too, was a graduate of yale college. he afterward married mrs. greene. he became mr. whitney's partner in may, . perhaps you wonder why the machine was called a gin. it was a short way of saying engine. a gin is a machine that aids the work of a person. the cotton-gin was made to work much the same as the hand of a person. it dragged the cotton away from the seed. and now begins the sorrowful part of the story. before mr. whitney could get his patent, several other gins had been made. each claimed to be the best. the plans were all stolen from mr. whitney's. [illustration: roller-gin.] one was the roller-gin. this crushed the seed in the cotton. of course this injured the cotton. another was the saw-gin. this was exactly like mr. whitney's, except that the saws were set differently. many lawsuits were begun. mr. whitney went to connecticut. there he had a shop for making the gins. when the suits began he had to return to georgia. in this way two years went by. by this time everyone knew the value of the gin. mr. whitney went to new york. there he became ill. his illness lasted three weeks. then he was able to go on to new haven. [illustration: saw-gin, .] there he found that his shop had been destroyed by fire. all his machines and papers were burned. he was four thousand dollars in debt. but neither mr. miller nor mr. whitney were the kind of men who give up easily. mr. miller wrote that he would give all his time, thought, labor, and all the money he could borrow to help. "it shall never be said that we gave up when a little perseverance would have carried us through," he said. about this time bad news came from england. the cotton, you remember, was then all sent there for manufacture. english manufacturers now claimed that the cotton was injured by the gin. this was in . miller and whitney had thirty gins working in different places in georgia. some were worked by cattle and horses. others were run by water. soon, however, the manufacturers found that the whitney cotton gin did not injure the cotton. the first lawsuit was decided against miller and whitney. they asked for another trial. but this was refused them. everywhere through the south they were cheated and robbed. yet all the time the south was growing richer because of the cotton gin. slaves grew more and more valuable. for negroes can endure the heat of the cotton fields. but white men can not. the planters of the south bought more and more slaves. so slavery grew stronger because of the cotton gin. several states made contracts with mr. whitney. they agreed to pay him certain sums of money. but south carolina broke her contract. all these things made mr. whitney sick at heart. he said that he had tried hard to do right by every one. and it stung him to the very soul to be treated like a swindler or a villain. the people of georgia tried to prove that somebody in switzerland had invented the cotton gin. tennessee broke its contract. there were high-minded men who tried to help mr. whitney. they were able to do only a little for him. in , mr. miller died. mr. whitney was then left to fight his battles alone. things grew a little brighter as time went on. mr. whitney received some money on his invention. but the greater part of it had to be spent in lawsuits. a suit was begun in the united states court. but the time of his patent was almost out. he had made six journeys to georgia. one gentleman said that he never knew another man so persevering. in , mr. whitney made a contract with the government of the united states. by this contract he was to manufacture fire-arms. he established his factory near new haven. the place is now called whitneyville. it is a beautiful place. a waterfall furnished the power to run his machinery. here mr. whitney worked hard. he had machinery to make. he had to teach his own workmen. for eight years he worked to fill this contract. he arose as soon as day appeared. look in any part of the factory you might, you would see something which he, himself had done. he improved many tools. he made better guns than had ever been made. so that for these things, too, our country is indebted to mr. whitney. in , he made new contracts. another war with england began in that year. mr. whitney's guns never failed to be all right. other men took contracts of the same kind. but their guns were failures. mr. calhoun, the secretary of war, said to mr. whitney, "you are saving your country seventy-five thousand dollars a year." this was by his improvements in fire-arms. mr. whitney tried to get the government to extend the time of the patent upon the cotton-gin. but this was refused. that did not seem very grateful, did it? robert fulton, the inventor of the first steamboat, was his friend. they had many troubles in common. mr. whitney's last days were his happiest days. such patience, perseverance, and skill must count in the long run. his factory made him quite a rich man. some of the southern states showed their gratitude. in , mr. whitney married miss edwards of connecticut. he had a son and three daughters. the people of new haven respected him. they gave him great honor. he died on january , . the little cotton-gin had done a great work. the sunny south was covered with beautiful plantations. the cotton fields shone in the sunlight. [illustration] riches were beginning to fill the pockets of the planters. only one blight remained upon the land. this was the dreadful system of slavery. and that, too, has been destroyed. we wish that mr. whitney might see the south of to-day. he did not live to know how great a curse slavery might be. he did not foresee that his cotton-gin might help to cause a great war. yet the blue and the gray fought and died. the blood of many a hero stained a southern field. all this that the cotton-pickers might be free! all this that our country might be truly "the land of the free and the home of the brave!" [illustration: s.f.b. morse.] samuel finley breese morse. if everything were now as it was in , what a queer place this world of ours would be to us! a hundred years ago! suppose we imagine ourselves living in the year . the railroads then were very few and poor. "fulton's folly," the first steamboat, had not yet frightened the sailors in new york harbor, with its long line of black smoke. lighting by means of gas was yet unknown. electric lights were not even dreamed of. even kerosene, which we think makes so poor a light, was then unused. so there are many, many things, common and useful to us now, which were unknown to the world in . you have heard of the giant, steam. there is yet another giant which god has placed in the world for man's use. this is electricity. is it not strange that this great power should have been so long unused in the world? boys and girls can understand how useful this power now is. so you will be interested in knowing something of the man who helped to introduce to the world this great giant, electricity. the baby who was given this long name, samuel finley breese morse, was born in charlestown, massachusetts. the date of his birth was april , . he was called samuel finley for his great-grandfather. his mother's name, as a girl, was elizabeth breese. you will see that he won fame enough to cover each and every one of these names. finley morse had, as he grew older, two brothers younger than himself. their names were sidney e. morse, and richard cary morse. finley was sent first to an old lady's school. he was but four years old when he started. the school was very near his home. the school mistress was known as, "old ma'am rand." she was an invalid and unable to leave her chair. so she had a long rattan. when the children did not mind, she could, with her long rattan, reach them at the further side of the room. one punishment of mrs. rand's was to pin a naughty child to her dress. as early as this part of his life, finley morse tried his hand at drawing. he drew mrs. rand's picture upon a chest of drawers. instead of a pencil he used a pin. so mrs. rand pinned him to her dress. of course he did not like that. he tried to get away. this tore the dress. then mrs. rand had to use her rattan. when seven years of age finley was sent to school at andover. he went to phillip's academy. while there the father wrote letters to his boy. he gave his boy good advice. he told him about george washington. he also told him about another great man. this man was a statesman of holland. he did all the business for that republic. yet he had time to go to evening amusements. some one asked this statesman how he did this. he said there was nothing so easy, for that it was only doing one thing at a time, and never putting off anything until to-morrow that could be done to-day. finley's parents were always kind to him. he soon became a manly boy. he was the kind of boy who seemed to know that he must one day be a man. so he worked hard at school. he began early to think and act for himself. when he was but thirteen he wrote a sketch of the "life of demosthenes." he sent it to his father. this his father kept carefully. it showed the genius, learning and taste of his boy. this bright boy was ready for college at the age of fourteen. but his father thought it best to keep him at home for a year. finley, when a boy, was always fond of drawing. when but fifteen, he painted a fairly good picture in water colors. this represented a room in his father's house. his father, his two brothers and himself stood by a table. his mother sat in a chair. on the table was a globe, at which they were all looking. his room at college was covered with pictures of his own making. one of these was called, "freshmen climbing the hill of science." the poor fellows were scrambling to the top of a hill on their hands and knees. finley had taken no lessons in art, yet he drew many portraits. the other boys were all delighted to have their pictures drawn by him. they paid him a dollar apiece. this kept him in spending money. he also painted upon ivory. for these he had five dollars each. so, when finley morse graduated from yale college, he was more fond of drawing and painting than of anything else. finley at this time was a fine looking boy. he had a pleasant smile. he was always courteous. every one liked him. he was as fond of a frolic as any one. at one time the college cooks did not do their work to suit the boys. so the boys gave them a mock trial. they sent a report of the trial to the college president. the bad cooks were dismissed. afterwards the boys had better things to eat. at another time the boys went to a paper mill near by. they bought a great quantity of paper. this they made into a baloon. it was eighteen feet in length. they filled it with air, and sent it on its journey. it sailed finely, and soon was out of sight. they tried it again. the second time it took fire and was soon nothing but ashes. about this time finley heard his first lecture upon electricity. after graduating, he returned to his father's house in charlestown. there he wrote a letter to his brothers with a queer kind of ink. the writing did not show at all until heated by fire. his brothers had to write to him to find out how to read it. about this time finley made a new friend. this friend was washington allston. mr. allston was a great painter. he learned to love finley morse. mr. allston spent most of his time in london. finley begged his people to allow him to go to london with mr. allston. they finally gave their consent. so mr. morse made his first voyage across the atlantic. they landed at liverpool. they had to go from there to london in a stage coach. as soon as he arrived he wrote to his parents. in his letter he said that he wished they could hear from each other in an instant. "but three thousand miles are not passed over in an instant. so we must wait four long weeks before we can hear from each other again." even then he longed for a telegraph. in london he had the help of another great artist. this was benjamin west. he, too, was an american. mr. morse wished to become a student in the royal academy. he had to make a drawing of hercules. hercules, you know, was one of the heroes of early greece. the story is that he did very many brave deeds. finley's drawing was to be taken to mr. west. he worked very hard upon it for two weeks. then he went to mr. west with it. mr. west said, "very well, sir, very well; go on and finish it." "it is finished," replied finley. "oh, no," said mr. west. "look here, and here, and here." so, when the mistakes were pointed out, finley saw them. he took the drawing home and worked patiently for another week. then he brought it to mr. west again. mr. west handed it back to mr. morse, saying: "very well indeed, sir. go on and finish it." "is it not finished?" said mr. morse, for he was almost discouraged. "see," said mr. west, "you have not marked this muscle nor that finger joint." so another three days were spent on the drawing. again it was taken back. "very clever indeed," said mr. west, "very clever. now go on and finish it." "i cannot finish it," replied mr. morse. then the old man patted him on the shoulder and said: "well, i have tried you long enough. "now, sir, you have learned more by this drawing than you would have learned in double the time by a dozen half finished drawings. "finish one picture, sir, and you are a painter." mr. morse took this good advice. he went to work upon a large picture. it was a picture of the "dying hercules." he first modeled his picture in clay. this he did so well that he received a gold medal for it. this was on may , . his picture, too, was given great praise. it was counted as one of the twelve best among the two thousand pictures. so mr. morse went on patiently and carefully in this work. he made many good friends in london. one of these friends was the poet, coleridge. mr. morse was a great comfort to his parents. he was careful with his money. he and a young mr. leslie, lived and painted together. he spent all his money to get helps in his work. he visited all the picture galleries, and spent days in the study of pictures. at this time england and america were at war. americans were sometimes made prisoners and kept in the prisons of england. mr. morse tried to help some of them. you have heard of the great french general, napoleon. you know of the many wars he had. in , napoleon met his enemies, the english and prussians. they had a battle at waterloo. napoleon was defeated. the people of england were anxious for news. but how slowly news came in those days! it took many days to carry the good tidings. the battle was fought on the th day of june. it was not until july that the news came of the victory of the english general. mr. morse wrote about it to his parents. he told how anxiously the people had waited. finally the people heard the booming of cannon. the bells were rung. people laughed and cried for joy. would it not seem strange to us now to wait for our news so long? yet the inventor of the telegraph had to wait often very long. but at last the time came for mr. morse to return to america. he sailed in august, . he bore with him the good wishes of his many friends in london. he had a stormy voyage. a ship signaled his ship for help. the captain did not wish to send help. he said he had all he could do to attend to his own ship. mr. morse told him that, if he did not help them, he would publish the facts when they reached america. so the captain thought better of it. he helped to save the ship. when he landed on his return mr. morse found that the people of america had heard of him. they knew of the fine pictures he had painted. he was now but twenty-four years of age. he set up a studio in boston. but the people of america were not as interested in art then as now. he waited many months for something to do. but nobody came for a picture. he left boston almost penniless. then he began painting portraits in different places. he received fifteen dollars for each portrait. he went to concord, new hampshire. there he met a beautiful young lady. her name was lucretia p. walker. she had a very sweet temper. she always used good sense. mr. morse became more and more successful with his portraits. he received more money for them. he went on a journey to the south. there he found much to do. he made three thousand dollars. then he came back to concord. there he married miss walker. mr. and mrs. morse lived for a few years in south carolina. then they came to new haven, connecticut. his father came to live with them there. mr. morse began to paint a great picture at washington. it was called "the house of representatives." washington is the capital city of the united states. the picture, when finished, was very beautiful. it was sold at last to an englishman. about this time a great friend of america visited washington. have you heard of general la fayette? you can read what great things he did for our country. every american loved him then. even the people who live now, love his memory. mr. morse was engaged to paint the portrait of general la fayette. he began the picture. before he had finished, he received dreadful news from home. his loved wife had died very suddenly. he hastened home. it seemed too hard to bear. not long afterwards he lost his father. he then went to live in new york. there he worked hard at his art. his artist friends made him president of their society. this was the national academy. while in new york he heard some lectures about electricity. he thought about it and talked much with his friends. he wished to visit beautiful italy. so, in , he sailed for europe. his friends there gave him a hearty welcome. he visited many cities. he met general la fayette again. he visited him in his home. mr. morse had always been fond of inventions. he himself invented a pump at one time. at another, he tried his hand at making a machine for cutting marble. he was always experimenting with colors, and other things used by artists. the year had arrived. you will see, by and by, that it is a good date to remember. people knew almost nothing about speed in traveling. in that year the longest railroad was in the southern part of the united states. it was one hundred thirty-five miles long. the next longer was in england. it was thirty miles long. the next was in massachusetts. it was ten miles long. the mails were carried in coaches. on the first day of october, , mr. morse sailed for america. the name of this ship was the "sully." the passengers were much interested in some things which had lately been found out about electricity. people had long known that lightning and electricity were the same. signals had been made with electricity. but the thought which came to mr. morse had never entered the mind of man before. he could think of nothing but a telegraph. he thought night and day. he seemed to see the end from the beginning. as he sat upon the deck of the ship after dinner, he drew out a little note book. he began his plan in this little book. from the beginning he said, "if a message will go ten miles without dropping, i can make it go around the globe." and he said this again and again during the years that came after. sleep forsook him. but one morning at the breakfast table he announced his plan. he showed it to the passengers. and five years after, when the model was built, it was found to be like the one shown that morning on board the ship "sully." "the steed called lightning (say the fates) was tamed in the united states; 'twas franklin's hand that caught the horse, 'twas harnessed by professor morse." upon landing in america a long struggle began. for twelve long years, mr. morse worked to get people to notice his invention. [illustration: diagram showing the morse alphabet and arrangement of the telegraph line.] it would take much money to construct a real telegraph. but money mr. morse did not have. he had three motherless children to provide for. he lived in a room in a fifth story of a building belonging to his brothers. this room was his study, studio, bed chamber, parlor, kitchen, drawing room and work shop. on one side of the room was his cot bed. on the other were his tools. he brought his simple food to his room at night. this he did, that no one might see how little he had to eat. he often gave lessons in painting. one pupil did not pay promptly. mr. morse asked to be paid. the pupil gave him ten dollars, asking if he would accept it. he said it would keep him from starving. he had had nothing to eat for twenty-four hours. the government, at this time, was giving some work to american artists. mr. morse knew he deserved to have a picture to paint. but, through a mistake, he was not given one. he felt much hurt by this. but perhaps he would not have pushed his telegraph through, if he had been given plenty of painting to do. as it was, morse, the painter, became morse, the inventor. it was not until that mr. morse had his wonderful invention ready to exhibit. during that year many people saw it. many thought it a silly toy. few dreamed of its importance. mr. alfred vail, whose father and brother had large brass and iron works, was one of those who believed in it. mr. vail decided to assist mr. morse. he was young and liked machinery. long after, mr. morse said that much of the success of the telegraph was due to mr. vail. in , mr. morse asked congress to give him aid. he wished to build a telegraph between baltimore and washington. the president and others saw the telegraph exhibited. a gentleman, named mr. f.o.j. smith, helped mr. morse with money. but many congressmen laughed at the idea. do you not think they felt ashamed when they found how great a thing they had been laughing at? while waiting for congress to decide, mr. morse went to europe again. he tried to get a patent in london, but it was refused him. the french people gave him a paper which didn't mean much. he met some great men, however, who did all they could for him. did you ever see a daguerreotype? it is an old fashioned portrait. perhaps you can find some at home. mr. morse met in paris the man who first took these pictures. his name was mr. daguerre. you see how the pictures were named. he was exhibiting his pictures at this time. so the two greatest things in paris in those days were the electro-magnetic telegraph and daguerreotypes. mr. daguerre and mr. morse became fast friends. mr. daguerre taught mr. morse how to take daguerreotypes. when mr. morse returned to america, he took some portraits of this kind. he also taught others how to do so. having returned to america, he found plenty to do. he wished to try the telegraph under water. he arranged about two miles of wire. he put it into new york harbor. a row boat was used in placing it. it was a beautiful moonlight night. people walking along the shore might well wonder what kind of fish were to be caught with such a long line. at day break professor morse was ready for his experiment. two or three characters were sent on the line. then no more could be sent. some sailors, in pulling up their anchor, had caught the wire. they pulled in about two hundred feet. then they cut the wire. so ended the first cable. the vails had been good friends to mr. morse. but they became afraid to spend any more money. then, indeed, mr. morse was in despair. a bill had been brought before congress, asking for thirty thousand dollars. this was to build the trial telegraph line. oh, how anxiously mr. morse waited! delay after delay came. many congressmen in their speeches, made all manner of fun of the bill. twilight came upon the evening of march rd, . it was the last day of the session of congress. there were still one hundred and nineteen bills to dispose of. it seemed impossible that the telegraph bill could be reached. mr. morse had patiently waited all day. at last he gave up all hope. he left the building and went to his hotel. he planned to leave for new york on an early train. as he came down to breakfast next morning, a young lady met him. "i have come to congratulate you," she exclaimed. "upon what?" inquired the professor. "upon the passage of your bill," she replied. "impossible! its fate was sealed last evening. you must be mistaken." "not at all," said the young lady; "father sent me to tell you that your bill was passed. it was passed just five minutes before the close of the session." mr. morse was almost overcome with the news. he promised the young lady that she should send the first message over the new line. mr. morse received a sad message in the midst of his joy. this was the news of the death of his dearest friend, mr. allston. he hastened to the home of his friend in cambridge. the brush with which mr. allston had been painting was still moist. mr. morse begged this as a memorial of his friend. he afterwards gave it to the national academy. now that the bill was passed, how hard he and his friend worked to build the line! they tried putting the wires underground. but this proved very expensive. then they tried the poles as we have them now. this succeeded nicely. was the year for the appointing of a new president. the whig party were to hold their convention at baltimore, in may. the managers of the telegraph worked hard to get the line done before the meeting. and, although the line was not finished, signals were arranged by which the message could be given. at last the day came. henry clay was nominated for president. the news was sent by the wires to washington. passengers arrived from baltimore an hour later. they were astonished to find the news already known. on the th of may the line was ready for its test. every one was anxious. mr. vail was at the baltimore end of the line. miss ellsworth, the young lady who had the promise of sending the first message, was with mr. morse. remember the twelve long, weary, anxious years, during which mr. morse had worked and waited. it was an anxious moment. miss ellsworth chose her message from the bible. it is found in numbers, rd chapter, rd verse. the words are: "what hath god wrought!" this was received at once by mr. vail. professor morse said this of the words of the message:-- "it baptized the american telegraph with the name of the author." he meant by this, that god was the author of the telegraph. what a glad, happy time followed! everybody congratulated mr. morse. the democratic convention took place two days later. there was much excitement. james k. polk was nominated for president. all sorts of messages were sent over the new telegraph line. mr. morse loved his country. and through his whole life worked for its interests. he rejoiced in having his invention called an american invention. he was at one time in europe. his friend, mr. f.o.j. smith, was embarking on his voyage for home. mr. morse said to him:-- "when you arrive in sight of dear america, bless it for me. "and when you land, kiss the very ground for me. "land of lands! oh, that all our country-men would but know their blessings! "god hath not dealt so with any nation. "we ought to be the best, as well as the happiest and most prosperous of all nations. "nor should we forget to whom we are in debt for all these blessings. "'righteousness exalteth a nation, but sin is a reproach to any nation.'" * * * * * there were still many hard things for mr. morse to endure. wicked men tried to steal his invention from him. they pretended to have invented telegraphs. the nations of europe did not treat him justly. but, little by little, the telegraph lines were built over the country. little, by little, the world came to know and love the name of samuel f.b. morse. honors of all sorts were given him. but, through all, he was the same kind, patient man. the sultan of turkey was the first foreign prince to honor mr. morse. but he was followed by many others. you have noticed that mr. morse never had a chance to enjoy a home. in , he bought a beautiful home upon the hudson. in the following year he married miss griswold, a lady born at sault ste. marie. they called their new home locust grove. there they enjoyed life greatly. professor morse had a telegraph instrument in his study. he afterwards bought a beautiful home in new york city. there they spent their winters. these words were written by a friend to mrs. morse, alluding to her husband:-- "though he did not 'snatch the thunder from the heaven,' he gave the electric current thought, and bound the earth in light." to mr. morse belongs also the honor of the submarine telegraph. a successful telegraph of this kind was laid near new york city. other gentlemen became interested in this. chief among these were mr. cyrus w. field and his brother david dudley field. the story of the cable laid across the atlantic is a long one. but mr. morse lived to see this, too, a success. when mr. morse was eighty years of age, his statue was erected in central park, new york. this was done by the telegraph operators of the country. it represented mr. morse as sending the first message of the telegraph, "what hath god wrought." mr. morse was present when the statue was unveiled. in he became very ill. his busy life was at an end. the whole country mourned, as news flashed over the wires that professor morse was dying. the light was going out of those bright, kind eyes. the fingers that harnessed the steed, lightning were powerless. the great brain, that had worked so hard for the world, was ready for rest. the great heart, that never kept an unkind thought, ceased to beat. all america mourned for him. messages were received from europe, asia and africa, paying tribute to the dead. few men have lived such lives as did samuel finley breese morse. [illustration] [illustration: peter cooper.] peter cooper. on the seventh of april, in , the great city of new york was in mourning. flags were at half-mast. the bells tolled. shops were closed, but in the windows were pictures of a kind-faced, white-haired man. these pictures were draped in black. all day long tens of thousands of people passed by an open coffin in one of the churches. some of these people were governors, some millionaires. there were poor women, too, with little children in their arms. there were workmen in their common clothes. there were ragged newsboys. and all these people had aching hearts. the great daily papers printed many columns about the sad event. people in england sent messages by the atlantic cable that they, too, had sad hearts. who was this man for whom the world mourned on that april day? was he a president? oh, no. a great general? far from it. did he live magnificently and have splendid carriages and fine diamonds? no, he was simply peter cooper, a man ninety-two years old, and the best loved man in america. had he given money? yes, but other men in our country do that had he traveled abroad, and so become widely known? no, he would never go to europe because he wished to use his money in a different way. why, then, was he loved by so many? one of the new york papers gave this truthful answer: "peter cooper went through his long life as gentle as a sweet woman, as kind as a good mother, as honest as a man could live, and remain human." some boys would be ashamed to be thought as gentle as a girl, but not so peter cooper. he was born poor, and was always willing that everyone should know it. he despised pride. when his old horse and chaise came down broadway, every cartman and omnibus driver turned aside for him. though a millionaire, he was their friend and brother, and they were proud and fond of him. he gave away more than he kept. he found places for the poor to work if possible. he gave money to those he found were worthy. and though he was one of the busiest men in america, he always took time to be kind. his pastor, mr. collyer, said this of him:-- "his presence, wherever he went, lay like a bar of sunshine across a dark and troubled day. i have seen it light up the careworn faces of thousands of people. it seemed as if those who looked at him were saying to themselves; 'it cannot be so bad a world as we thought, since peter cooper lives in it and blesses us.'" but how did this poor boy become a millionaire? and how did he get people to love him so? he did it, boys and girls, by making up his mind to do it at first, and then sticking to it. nobody could have had more hard things to overcome than peter cooper. his parents were poor and had nine children. his father moved from town to town, always hoping to do better. he forgot the old saying, "a rolling stone gathers no moss." when the fifth baby was born, he was named after the apostle peter, because his father said, "this boy will come to something." but he was not a strong boy. he was able to go to school but one year of his life, and then only every other day. his father was a hatter, and when peter was eight years old he pulled hair from rabbit skins for hat pulp. year after year he worked harder than he was able, but he was determined to win. when his eight little brothers and sisters needed shoes, he ripped up an old one to see how it was made. always after that he made the shoes for the family. do you think a lazy boy would have done that? when he was seventeen, he bade his anxious mother good-bye, and started for new york to make his fortune. do you know what a lottery is? it is a way dishonest people have of making money. tickets are sold for prizes, and of course only one person can get the prize, while all the rest must lose their money. soon after peter cooper reached new york he saw an advertisement of a lottery. he might draw a prize by buying a ticket. each ticket cost ten dollars. peter had just that much money. he thought the matter over carefully. he wished very much to have some money, for then he could help his mother. so he bought a ticket, and drew--nothing. poor boy! he was now penniless. but he never touched games of chance again. years afterward he used to say, "it was the cheapest piece of knowledge i ever bought." day after day the tall, slender boy walked the streets of new york looking for work. at last he found a place. it was in a carriage shop. here he bound himself as apprentice for five years at two dollars a month and board. you see he could buy no good clothes. he had no money for cigars or pleasures of any kind. he helped to bring carriages for rich men's sons to ride in. there is an old saying, that "everybody has to walk at one end of life," and they are fortunate who walk at the beginning and ride at the close. when his day's work was over he liked to read. his companions made fun of him because he would not join them. he made a little money by extra work. he hired a teacher, to whom he recited evenings. he was often very tired, but he never complained. he had many friends because he was always good-natured. he used often to say to himself, "if ever i get rich i will build a place where the poor girls and boys of new york may have an education free." wasn't that a queer thought for a boy who earned only fifty cents a week? yet perhaps his even dreaming such dreams helped him to do the great things of which i shall tell you. now, peter noticed that the tools which they worked with in the carriage shop were not very good. so he began to try to make better ones. he succeeded in doing so, but mr. woodward, the man for whom he worked, had all the benefit of his work. but at last peter's apprenticeship was over. much to his surprise mr. woodward one day called him into his office. "you have been very faithful," he said, "and i will set you up in a carriage manufactory of your own. "you could pay me back the money borrowed in a few years." this was a remarkable offer for a poor young man. but peter had made it a solemn rule of his life never to go in debt. so he thanked mr. woodward very earnestly, but declined his offer. it was then mr. woodward's turn to be astonished. but he knew peter was right, and respected his good judgment in the matter. we may now call peter cooper a mechanic. a mechanic is one who has skill in using tools in shaping wood, metals, etc. peter now found a situation in a woolen mill at hempstead, long island. here he received nine dollars a week. still he kept trying to find better ways of doing things. he invented a machine for shearing cloth, and from that earned five hundred dollars in two years. with so much money as this he could not rest until he had visited his mother. he found his parents deeply in debt. he gave them the whole of his money, and promised to do more than that. his father had not made a mistake in naming him after the apostle peter. during this time mr. cooper had learned to know a beautiful girl named sarah bedell. this girl became his wife. they moved to new york. here mr. cooper had a grocery-store. a friend advised him to buy a glue factory which was for sale. he knew nothing of the business, but he thought he could learn it. he soon made not only the best glue, but the cheapest in the country. for thirty years he carried on this business almost alone, with no salesman and no book-keeper. he rose every morning at daylight, kindled his factory fires, and worked all the forenoon making glue. in the afternoon he sold it. in the evenings he kept his accounts, wrote his letters, and read with his wife and children. he worked this way long after he had an income of thirty thousand dollars a year. this was not because he wanted to have so much more money for himself. you remember he had a plan to carry out which would take much money. that was to build his free school for the poor. he had no time for parties or pleasures. but the people of new york knew he was both honest and intelligent. they asked him to be a member of the city council, and president of their board of education. peter cooper never refused to do anything which might help others. so he did not refuse these offices. i must tell you now about mr. cooper's first child, and how fine a thing it was to have an inventor for a papa. mr. cooper made for this baby a self-rocking cradle, with a fan attached to keep off the flies, and with a musical instrument to soothe the dear baby into dreamland. mr. cooper's business prospered. [illustration: the "best friend,"--first locomotive built in america. built by peter cooper.] once the glue factory burned, with a loss of forty thousand dollars. but at nine o'clock the next morning there was lumber on the ground for a factory three times as large as the one burned. he then built a rolling mill and furnace in baltimore. they were then trying to build the baltimore and ohio railroad. only thirteen miles of the road had been finished. the directors were about to give up the work. there were many sharp turns in the track. the directors were discouraged because they thought no engine could be made to make those turns. mr. cooper knew that this road would help his rolling mill. nothing could discourage him. [illustration: first train in america.] he went to work and made the first locomotive made in america. he attached a box-car to it. then he invited the directors to take a ride. he took the place of engineer himself. away they flew over the thirteen miles in an hour. the directors took courage, and the road was soon finished. years after, when mr. cooper had become a great man, he was invited to visit baltimore. the old engine was brought out, much to the delight of the people, who cheered again and again at sight of it. mr. cooper soon built at trenton, n.j., the largest rolling mill in the united states. he also built a large blast furnace, and steel and wire works in different parts of pennsylvania. [illustration: new york central empire state express. fastest locomotive in the world. "engine ." copyrighted by a.p. yates, by permission of new york central r.r.] he bought the andover iron mines. he built eight miles of railroad in this rough country. over this road he carried forty thousand tons a year. the poor boy, who once earned but twenty-five dollars a year, had become a millionaire. no good luck accomplished this. but these are the things that did it: hard work. living within his means. saving his time. common sense, which helped him to look carefully before he invested his money. promptness. keeping his word. mr. cooper was honorable in all his business. once he said to a friend who had an interest in the trenton works: "i do not feel quite easy about the amount we are making. we are making too much money. it is not right." the price was made lower at once. do you not think peter cooper was an unusual kind of a man to lower the price of an article just because the world needed it so much? he was now sixty-four years of age. he had worked day and night for forty years to build his free college. he had bought the ground for it. and now for five whole years he watched his great, six-story, brown-stone building as it grew. the man who was once a penniless lad should teach many through these great stones some of the lessons he knew so well. some of these are industry, economy and perseverance. the words which he wrote and placed in a box in the corner stone are not too hard for you to read. "the great object that i desire to accomplish by the erection of this institution is to open the avenues of scientific knowledge to the youth of our city and country, and so unfold the volume of nature that the young may see the beauties of creation, enjoy its blessings, and learn to love the author from whom cometh every good and perfect gift." but would the poor young men and women of new york who worked hard all day care for an education? some people said no. but mr. cooper thought of his own boyhood, and believed that young people loved books, and would be glad of a chance to study them. [illustration: cooper institute, new york city.] and when the grand building was opened students crowded in from the shops and factories. some were worn and tired, as peter cooper had often been in his youth. but they studied eagerly in spite of that. every saturday night two thousand came together in the great hall. there the most famous people in the world lectured before them. every year nearly five hundred thousand read in the free library and reading rooms. four thousand pupils came to the night school to study science and art. the white-haired, kindly-faced man went daily to see the students. they loved him as a father. his last act was to buy ten type-writers for the girls in that department. has the work paid? ask any of those young men and women who have gone out from cooper institute to earn their own living. not one of them had to pay a cent for his education. no one is admitted who does not expect to earn his living. mr. cooper did not love weak, idle young people, who are willing their parents shall take care of them. the work has grown so large that more money is needed--perhaps another million. mr. cooper gave it two millions of dollars. many are turned from the doors because there is no more room. some of the pupils from the institute have become teachers. one receives two dollars an hour for teaching. several engrave on wood. one receives one hundred and fifty dollars a month. another, a lady, married a gentleman of wealth, and to show her gratitude to mr. cooper has opened another "free school of art." is it any wonder that when peter cooper died thirty-five hundred came up from the institution to lay roses upon his coffin. his last words to his son and daughter were not to forget cooper union. they have just given one hundred thousand dollars to it. mr. cooper had many friends among the great and good of the land. he died as unselfishly as he had lived, and who can measure the good he did in the world? [illustration: edison.] a great inventor. thomas a. edison was born in milan, ohio, february , . there was nothing in milan to make a boy wish to do great deeds. there was a canal there. thomas had one great help--his mother. she had been a teacher. her greatest wish for her son was that he should love knowledge. thomas had a quick mind. he inquired into everything. he was fond of getting every little thing well learned. he never did things by halves. he loved to try experiments. when thomas was a very little boy, only six years old, and still wearing dresses, he did a very funny thing. he was one day found missing. his frightened parents searched for him long and anxiously. where do you think he was found? they found him in the barn, sitting on a nest of goose eggs, with his dress spread out to keep them warm. he thought he could hatch some goslings as well as the mother-goose. he had placed some food near by so that he might stay as long as necessary. he went to a regular school only two months. his father and mother were his teachers. his father, to encourage him to read, paid him for every book which he read. but thomas did not need to be paid to read, for he read with pleasure every volume he could get hold of. when he was ten years old, he was reading such books as gibbon's "history of rome," hume's "history of england," and sear's "history of the world." besides these, he had read several books about chemistry. he loved to read about great men and their deeds. when he played, it was at building plank roads, digging caves, and exploring the banks of the canal. when only twelve years of age, he was obliged to go out into the world and earn his own living. he obtained a place as train-boy on the grand trunk railroad, in eastern michigan. he sold apples, peanuts, song-books, and papers. he had such a pleasant, sunny face that everyone liked to buy of him. he succeeded so well that soon he had four boys working under him. this was not enough to keep him busy. he had never lost his liking for chemistry. he managed to trade some of his papers for things with which to try experiments. he found a book which helped him. he fitted up an old baggage car as a room for his experiments. he was afraid some one would touch his chemicals; so he labelled every bottle, "poison." soon this busy boy had another business. he bought three hundred pounds of old type from the "detroit free press." he had gained a little knowledge of printing by keeping his eyes open when buying papers. soon a paper, called the "grand trunk herald," was printed by master tom. this paper was twelve by sixteen inches in size. it was filled with railway gossip and many other things of interest to travelers. baggagemen and brakemen wrote articles for it. george stephenson, who built a great bridge at montreal, liked it so well that he ordered an extra edition for his own use. everybody liked it. the "london times" spoke of it as the only paper in the world published on a railway train. but the "grand trunk herald" had a sad ending. do you know what phosphorus is? it is a substance which will take fire of itself if not kept under water. tom's bottle of phosphorus was thrown to the floor by the jolting of the car. soon everything was on fire. the conductor rushed in and threw all the type and chemicals out of the car. he also gave the young chemist a thrashing. poor thomas gathered up what was left. he put his things in the basement of his father's house. thomas's father now lived at port huron. thomas always slept at home. he now printed another and a larger journal. this was called the "paul pry." in this he published an article which one of his subscribers did not like. the angry man, meeting thomas on the banks of the st. clair river, picked him up and threw him in. thomas was a good swimmer and reached the shore in safety. but he did not care for the printing business any more. during the four years in which thomas edison was a train-boy, he had earned two thousand dollars and given it all to his parents. when in detroit, he read as much as possible from the public library. once he thought he would begin with number one and read each of the thousand volumes. he read until he had finished a long row of hard books on a shelf fifteen feet long. then he made up his mind that anyone would have to live as long as methuselah to read a library through, and gave up the plan. thomas became interested in telegraphy during the civil war. he used to telegraph the headings in his paper ahead one station. he thought this a good way to advertise. he finally bought a good book about electricity. soon the basement of the house at port huron was filled with many things beside printing presses. he used stove-pipe wire, and soon had a telegraph wire between the basement and the home of a boy friend. perhaps it was a good thing that all the children in the edison family were not like thomas. had they been, the poor old house would scarcely have held them. but the mother was proud of all that thomas did. she did not worry over the bottles, wires, strings, and printing presses. about this time thomas did a brave thing. the station agent at mt. clemens had a baby boy two years old. this baby crept on to the track in front of a train just coming in. quick as thought, young edison rushed to the track and saved the child at the risk of his own life. the baby's father was very grateful and offered to teach thomas telegraphy. of course, thomas was very happy, and accepted the offer. he came to mt. clemens every evening, after working hard all day. he did so well that, in five months, he was given a position at port huron. he earned six and one-quarter dollars a week. he worked almost night and day, so that he might learn all he could about it. his mother said that the world would hear from her boy some day. afterwards he worked in several places. in indianapolis, though not yet seventeen, he invented his first telegraph instrument. this was thought to be a great thing for so young a boy to do. he lost several places because he tried new ways. at last, he was obliged to walk nearly all the way to louisville because he had no money. here he was given a good position. he stayed several years. under the telegraph rooms was an elegant bank. one day, while experimenting, he spilled a great bottle of acid. this acid went through the floor into the bank below. of course it spoiled the ceiling, handsome carpets, and furniture. so the unfortunate inventor had to leave louisville. he finally gave up trying to be a telegraph operator. he opened a little shop. he invented many things, and kept on thinking. he could not make his inventions successful, for he had little money. he thought so hard that he forgot everything else. once he was asked to speak before a company. he forgot all about it. they sent for him, and found him at the top of a house putting up a telegraph line. he went in his working clothes to make his speech. he felt queer when he found a room full of elegant ladies. but he made a good speech. then he went to new york. there he walked the streets three weeks, looking for work. nobody wanted a man who experimented. by chance, he one day went into an office where the telegraph instrument was out of repair. he offered to fix it. they laughed at him, but let him try. he succeeded in fixing it. they gave him a good position. from this time on there were better times for him. after this the world soon sang his praises; and, in the next ten years, fortune poured into his lap half a million dollars. this was the result of his thinking. the man who was in charge of the united states patent office called him "the young man who keeps the pathway to the patent office hot with his footsteps." mr. edison believed that two messages could be sent over the same wire at the same time. of course the world laughed at the idea. but soon our inventor managed to send four messages over the same wire at the same time. then the world stopped laughing. people said, "this young man is the greatest inventor of his age, and a discoverer as well." the grand trunk train-boy had proved a genius. when twenty-six years of age, he married a young lady of newark, miss mary stillwell. three years later he moved to menlo park. this was twenty-four miles from new york. it was not a pleasant place, but he hoped to work there in quiet. he had so many visitors that he could not work. he said, "i think i shall fix a wire to my gate, and connect it with a battery so that it will knock everybody over that touches it." but he was really kind. he would smile pleasantly, and explain patiently to anyone who wished to know about his inventions. at menlo park he built a great laboratory. this was filled with batteries and machinery. here all the world came to see his wonderful talking machine. it is called a phonograph. what do you think mr. edison called this machine? he said, "i have invented a great many machines, but this is my baby, and i expect it to grow up and support me in my old age." would you like to know the names of some of his inventions. one is the carbon telephone. the tasimeter measures the heat even of the far away stars. the electric pen multiplies copies of letters and drawings. over sixty thousand are now in use in this country. the automatic telegraph permits the sending of several thousand words over the same wire in one minute. [illustration] there are many others. do you wonder that he is called "the wizard of menlo park?" but his crowning discovery is the electric light. some gentlemen of new york put one hundred thousand dollars into mr. edison's hands. they told him to experiment until he could make a light which every one would be glad to use. many had tried to do this and had not succeeded. it is said that he tried two thousand substances for the arch in his glass globe before he found one which suited him. do you know what he chose at last? do you remember the plant which the boys and girls of india, china, and japan know so well? it is the bamboo. and it was bamboo which mr. edison chose. oh, how glad this light made many people! in ten cotton factories in one town were men, women, and children working. they worked in rooms where gas was used. the gas injured their eyes and health. now in those same factories there are sixty thousand electric lights. the bamboo burns six hundred hours before it has to be replaced. would you like a picture of mr. edison? close your eyes then and think of him like this. he is five feet ten inches high. his face is boyish, but earnest. he has light gray eyes. his hair is dark, slightly gray, and falls over his forehead. he is a pleasant man to see. he loves his work. for ten years he has averaged eighteen hour's work a day. you have seen that he is not a man to give up easily. once an invention of his--a printing press--failed. he took five men into the upper part of his factory. he declared he would never come down until it worked satisfactorily. for two days and nights, and for twelve hours more, he worked without sleep. he conquered the difficulty. then he slept thirty hours. he often works all night. he says he can work best when the rest of the world sleeps. but he likes fun, too. one day he said to his old friend, of whom he learned telegraphing, "look here--i am able to send a message from new york to boston without any wire at all." "that is impossible," said his friend. "oh, no, it's a new invention." "well, how is it done?" said mr. mckensie. "by sealing it up and sending by mail," was the comical answer. he has two children. one, a girl, mary, is nicknamed "dot." the other, a son, thomas, is called "dash." mr. edison doesn't like to have great dinners given in his honor. but the world gives him great honors. at the paris exposition in , two great rooms were filled with his inventions. the rooms were lighted with his lights. he receives letters daily in french, german, italian, spanish, russian, and turkish. mr. edison says, "anything is possible with electricity." that he is a genius, nobody can deny. but do you suppose he could have done all these things without his great reading, or if he had been a lazy person? * * * * * +--------------------------------------------------------------+ | typographical errors corrected in text: | | | | page : perserverance replaced with perseverance | | page : betwen replaced with between | | page : clemans replaced with clemens | | | +--------------------------------------------------------------+ * * * * * proofreading team at www.pgdp.net. [illustration] scientific american supplement no. new york, december , scientific american supplement. vol. xxiv., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. architecture.--notes on the construction of a distillery chimney--a new method of building lofty shafts, including a metallic frame and brick lining-- illustrations. the commercial exchange, paris--the new paris exchange now in process of erection.--present state of operations-- illustration. ii. astronomy.--the yale college measurement of the pleiades.-- dr. elkin's work with the repsold heliometer at yale college. iii. chemistry--new method for the quantitative determination of starch.--by a.n. asboth--determination of starch by its barium compound. synthesis of the alkaloids--a retrospect of the field of work so far traveled over by synthetical chemists, and future prospects. the chemical basis of plant forms--by helen c. de s. abbott --continuation of this important contribution to plant chemistry, one of the most valuable of recent chemical monographs. iv. electricity.--an electrical governor--a new apparatus for preserving a constant electromotive force with varying dynamo speed-- illustration. electric launch--a french government launch with krebs electric motor. the electric current as a means of increasing the tractive adhesion of railway motors and other rolling contacts.--by elias e. ries--a full review of this important subject, with accounts of its experimental examination. v. engineering--benier's hot air engine--a new caloric engine very fully illustrated and described-- illustrations. heating marine boilers with liquid fuel--a simple apparatus and recent experiments with the same.-- illustrations. the change of gauge of southern railroads in --by c.h. hudson.--the conclusion of the account of this great engineering feat, with tables of statistics and data-- illustrations. your future problems--by chas. e. emery--an address to the graduating class of the stevens institute, n.j.--a practical view of the engineering profession. vi. miscellaneous--a group of hampshire downs--a typical breed of sheep, their qualities and habits.-- illustration. vii. naval engineering--the spanish cruiser reina regente--a further description of this celebrated vessel-- illustrations. torpedo boats for spain--the azor and halcon, two yarrow torpedo boats, described and illustrated-- illustrations. viii. photography--how different tones in gelatino-chloride prints may be varied by developers.--twenty different formulæ for the above purpose. film negatives--eastman stripping films, their manipulation and development. ix. sanitation--french disinfecting apparatus--a portable apparatus for disinfecting clothes and similar objects-- illustration. x. technology.--the manufacture of cocaine--the extraction of cocaine with alkali and petroleum, with statement of percentage yielded by various leaves. the production of oxygen by brin's process--the commercial manufacture of oxygen by means of baryta-- illustrations. #transcriber's note: following entry not in original table of contents# deep sea dredgings: examination of sea bottoms. by thomas t.p. bruce warren. * * * * * benier's hot air engine. the hot air engine, although theoretically recognized for some time past as the most economical means of converting heat into motive power, has up to the present met with little success. this is due to the fact that the arrangement of the motors of this class that have hitherto been constructed has been such as to render them but slightly practical. in the benier hot air engine (illustrated herewith), however, obstacles that were once considered insurmountable have been overcome, and the motor presents many advantages over all the types that have preceded it. among such advantages we shall cite the possibility of utilizing air at a high temperature ( , or , degrees), while the rubbing surfaces remain at a moderate temperature ( or degrees). the fire grate is placed in the interior of the cylinder, and is traversed by the cold air forced by a pump. the expanded hot gases fill the cylinder and act against the piston directly above the grate. the type herewith illustrated is of horse power. the motive cylinder, cc', is bolted to the extremity of the frame, a. upon this latter is fixed a column, b, which carries a working beam, e. this latter transmits the motion of the piston, p, to the shaft, d. a pump, g, placed within the frame, forces a certain quantity of cold air at every revolution into the driving cylinder. the piston of this pump is actuated by the connecting rod, g', jointed to the lever, f', which receives its motion from the rod, f. a slide valve, _b'_, actuated by a cam, regulates the entrance of the cold air into the pump during suction, as well as its introduction into the cylinder. there is a thrust upon the piston during its upward travel, and an escape of hot gas through the eduction valve, _h_, during the downward travel. the cylinder is in two parts, c and c'. the piston, which is very long, rubs at its upper end against the sides of the cylinder, c. the lower end is of smaller diameter, and leaves an annular space between it and the cylinder. the grate is at the bottom of the cylinder, c'. the sides of the cylinder at the level of the fire box are protected with a lining of plumbago. when the piston is at the bottom of its travel, the eduction valve closes. the slide valve, _b'_, establishes a communication between the pump chamber and the cylinder. the air contained in the pump is already compressed in the latter to a pressure of nearly a kilogramme at the moment of the communication. this air enters the cylinder, and the communication between the latter and the pump continues until all the air is forced into the driving cylinder, the piston of the pump being at the bottom of its travel, and that of the cylinder about midway. [illustration: benier's hot air engine.] the air forced by the pump piston enters the cylinder through two conduits, one of which leads a portion of it toward the top of the cylinder, and the other toward the bottom. the lower conduit debouches under the grate, and the air that passes through it traverses the fire box, and the hot gas fills the cylinder. the conduit that runs to the top debouches in the cylinder, c, at the lower limit of the surface rubbed by the piston. the air that traverses this conduit is distributed through the annular space between the piston and cylinder. the hot gas derived from combustion can therefore never introduce itself into this annular space, and consequently cannot come into contact with the rubbing surfaces of the cylinder and piston. as the quantity of air introduced at every stroke is constant, the work developed at every stroke is varied by regulating the temperature of the gas that fills the cylinder. when the temperature falls, the pressure, and consequently the work developed, diminishes. this result is obtained by varying the respective quantities of air that pass through the fire box and around the piston. in measure as less air passes through the fire box, the quantity that passes around the piston augments by just so much, and the pressure diminishes. a valve, _n'_, in the conduit that runs to the fire box is controlled by the regulator, l', in the interior of the column. when the work to be transmitted diminishes, the regulator closes the valve more or less, and the work developed diminishes. the coke is put by shovelfuls into a hopper, i. four buckets mounted upon the periphery of a wheel, i', traverse the coke, and, taking up a piece of it, let it fall upon the cover, j, of the slide valve, _j_, whence it falls into the cavity of the latter when it is uncovered, and from thence into the conduit, _c'_, of the box, _j'_, when the cavity of the valve is opposite the conduit. from the conduit, _c'_, the coke falls upon the grate. a small sight hole covered with glass, in the cover, j, permits the grate to be seen when the cavity of the valve is opposite _c'_. as in gas engines, a current of water is made to flow around the cylinder, c', in order to keep the sides from getting too hot. in order to set the engine in motion, we begin by opening the bottom, c, of the cylinder, c', to clean the grate. this done, we close c and introduce lighted charcoal through the conduit, _c'_ (the valve being open). the valve is put in place, two or three revolutions are given to the fly wheel, and the motor starts. the feeding is afterward done with coke. the parts that transmit motion operate under conditions analogous to those under which the same parts of a steam engine do. the air pump sucks and forces nothing but cold air, and nothing but cold air passes through the distributing slide valve. the pump and valve are therefore rendered very durable. the piston and cylinder, at the points where friction exists, are at a temperature of or degrees. these surfaces are protected against hot gas charged with dust. the hot gas, which escapes from the cylinder through a valve, has previously been cooled by contact with the sides of the cylinder and by expansion. the eduction valve just mentioned works about like that of a steam engine, and it is only necessary to polish it now and then in order to keep it in good condition.--_annales industrielles._ * * * * * your future problems.[ ] [footnote : an address to the graduating class, stevens institute, hoboken, n.j., .] by charles e. emery. _mr. president and ladies and gentlemen:_ it has not been considered the duty of the speaker, in addressing the graduating class, to dwell on the triumphs of science or the advantage of a liberal education. these subjects have already been discussed, in connection with the regular courses of study, better, and more at length, than he could do. we propose rather to try and prepare the minds of the graduates for the practical problems before them. all young men are impressed with the consciousness of higher powers as they increase their stores of knowledge, and this feeling perhaps reaches its maximum with those who have made a specialty of the investigation and application of physical laws. young men who have learned how to harness the powers of nature and guide them to do their will are apt to belittle the difficulties they have yet to overcome, and have a false impression of the problems of life. this feeling is shown to a minimum extent by graduates of the stevens institute, on account of their careful practical training, in connection with the thorough study of principles; but it has been thought best for one from the outside world to supplement such teaching by calling to mind instances which may have a useful counteracting effect, and, like parables, serve the purpose of illustrative instruction. _gentlemen of the class of ' _: it was the pleasure of the speaker to address the class of ' , under the title of "how to succeed," some words of counsel and warning, which, if they left an impression of severity at the time, were apparently so well received afterward that he has been tempted to continue the general subject, with the title of "your future problems." the notation of your future problems will not be found at once among the known quantities, but with _x_, _y_, and _z_, at the other end of the alphabet. often word symbols will be applicable, expressing at times disappointment and pain, at other times renewed effort, and finally the active phases of individual thought and exertion. the first serious problem with many of you will be to secure satisfactory engagements. this problem cannot be illustrated by parables. it needs, in general, patient, unremitting, and frequently long continued effort. it may be that the fame of some of you, that have already acquired the happy faculty of making yourselves immediately useful, has already gone abroad and the coveted positions been already assured. to be frank, we cannot promise you even a bed of roses. we have in mind an instance where a superior authority in a large business enterprise who had great respect, as he should have, for the attainments of young gentlemen who have had the opportunities of a technical education, deliberately ordered out a competent mechanical engineer, familiar with the designs required in a large repair shop, and sent in his place a young gentleman fresh from school and flushed with hope, but who from the very nature of the case could know little or nothing of his duties at that particular place. he was practically alone in the drawing room, and did not know where to find such drawings as were required, and candor requires it to be said that he desired to ask many questions about those he did find. the superintendent unfortunately had nothing to do with his appointment, and rather resented it. so he did not trust any of his work, and the new comer was obliged to learn his practical experience at that establishment, where he was known as the mechanical engineer, by having all his work done over by the pattern maker or others, under the eye of the superintendent or master mechanic, and be subjected all the time to the jealousies and annoyances incident to such a method of introduction. his practical experience was certainly learned under difficulties which i trust none of you may experience. this statement is made that those of you who have not yet obtained positions may not envy those who have, and that each and all of you may be careful not to take a position so far above your experience, if not your capacity, as to become unpleasantly situated in the beginning. the educational facilities you have enjoyed are of such great value in some exceptional cases that the parties thus benefited may do you an injury by leading others to expect that you will be equally valuable in performing duties which require much more practical experience and knowledge of detail than it is possible that you could have obtained in the time you have been here. the incident is ripe with suggestions. no matter how humble a position you may take in the beginning, you will be embarrassed in much the same way as the young gentleman in question, though it is hoped in a less degree. your course of action should be first to learn to do as you are told, no matter what you think of it. and above everything keep your eyes and ears open to obtain practical knowledge of all that is going on about you. let nothing escape you of an engineering nature, though it has connection with the business in hand. it may be your business the next day, and if you have taken advantage of the various opportunities to know all about that particular matter in every detail, you can intelligently act in relation to it, without embarrassment to yourself and with satisfaction to your superior. above all, avoid conflict with the practical force of the establishment into which you are introduced. it is better, as we have at another time advised, to establish friendly relations with the workmen and practical men with whom you have to do. you are to be spared this evening any direct references to the "conceit of learning," but you are asked and advised to bear with the _conceit of ignorance_. you will find that practical men will be jealous of you on account of your opportunities, and at the same time jealous of their own practical information and experience, and that they may take some pains to hinder rather than aid you in your attempts to actively learn the practical details of the business. the most disagreeable man about the establishment to persons like you, who perhaps goes out of his way to insult you, and yet should be respected for his age, may be one who can be of greatest use to you. cultivate his acquaintance. a kind word will generally be the best response to an offensive remark, though gentlemanly words of resentment may be necessary when others are present. sometimes it will be sufficient to say, "i wish a little talk with you by yourself," which will put the bystanders at a distance and enable you to mature your plans. ascertain as soon as possible that man's tastes; what he reads and what he delights in. approach him as if you had no resentment and talk on his favorite topic. if rebuffed, tell a pleasant story, and persist from time to time in the attempt to please, until his hardened nature relaxes and he begins to feel and perhaps speaks to others favorably of you. st. paul has said: "for though i be free from all men, yet have i made myself servant of all that i might gain the more." this is the keynote of policy, and though in humbling yourself you control and hide your true feelings, recollect that all your faculties are given you for proper use. we have referred to some who have acquired the happy faculty of making themselves immediately useful. this is a much more difficult matter than the words imply. if one of you should be so fortunate as to be ordered to make certain tests almost like those you have already conducted here, or to tabulate the results of tests as you have done it here, or to make inspections akin to those which have been fully explained here, there is every probability the work would be done satisfactorily in the first instance. but let a much _simpler_ case arise, for instance, if a superior hand one of you a letter with the simple instructions, "get me the facts on that," you may be very much puzzled to know what is to be done and how to do it. it may be that the letter is a request for information in regard to certain work that was carried on in the past, in which case it will be necessary for you to hunt through old records, copy books, engineering notes, drawings, and the like, and get a list of all referring to the subject; to make an abstract of the letters and notes if they are at all complicated; and finally to lay the whole before the overworked superior in a business manner, that he largely from recollection, aided by the references and notes, can write an intelligent answer in a very brief period. the way not to do it would be to say, "yes, sir," very promptly, go off and not more than half read the letter, do something and be back in five minutes with some question or ill-digested answer; then upon receiving a polite hint as to the method to be employed, go off and repeat the operation the next five minutes; then on receiving a short reply, in what appeared to be an unnecessary tone of voice, get a little flurried perhaps, do worse next time, and in the end feel very unpleasant without having accomplished much, and make the gentleman seeking assistance lament the difficulty in teaching young men practical work. it is possible, on the contrary, for a young man to exceed his instructions and volunteer advice that has not been asked. if he has unfortunately gone too far for some time and been sharply spoken to, he may fail the next in not fully doing the work intended. simply putting down a column of figures would not necessarily mean tabulating facts. the arrangement and rearrangement of the columns aid in classifying such facts, so that the results shown by them will be readily seen and a great deal of labor saved in examination. a good rule in a case of this kind is to try and find some work done by other parties of a similar nature, and thereby ascertain what is needed and expected. reasonable questions to ascertain, where records are to be found and the kind of records accessible, are always proper if made at the proper time without interrupting an immediate train of thought; and with such information as a start, if a young man will endeavor to imagine himself in a place like that of the one who has finally to decide, and try to ascertain just what information will probably be required, then patiently go to work to find and present it in condensed shape, he from that moment really begins to be useful and his services will be rapidly appreciated. it is a good rule always to keep the memoranda obtained in accomplishing a result of this kind; so that if further information is required, the whole investigation need not be made over. this remark suggests another line of thought. some young men with quick perceptions get in the way at school of trusting their memories, and omit making complete notes of lectures or of the various tests illustrating their studies. this carelessness follows them into after life, and there are instances where young men, who can make certain kinds of investigations much better than their fellows, and promptly give a statement of the general nature of the results, have, when called on afterward for the details, forgotten then entirely, and their notes and memoranda, if preserved, being of little use, the labor is entirely lost. such men necessarily have to learn more careful ways in after life. it is a good rule in this, as in the previous case, to make and copy complete records of everything in such shape that they may be convenient for reference and criticism afterward. one of the important problems with which you will have to deal in the future is the labor question, and it is probable that your very first experience with it may be in direct antagonism with the opinions of many with whom you have heretofore been associated. it is an honor to the feelings of those who stand outside and witness this so-called struggle now in progress between capital and labor, that they believe the whole question can be settled by kindly treatment and reasonable argument. there are some cases that will yield to such treatment, and one's whole duty is not performed till all possible, reasonable, and humanitarian methods are adopted. there has been an excuse for the organization of labor, and it, to some small extent, still exists. time was that the surplus of unskilled labor was used on a mercantile basis to reduce wages to such an extent that it was almost impossible to rear a well nurtured, much less a well educated and well dressed family, and, moreover, the hours of labor in some branches of business were so long as to shorten the lives of operatives and make self-improvement impossible. the natural progress of civilizing influence did much to abate many of these evils, but the organization of labor removed sores that had not and perhaps could not have been reached in other ways. having then an excuse for organization, and supported by the success made in directions where public sympathy was with them, is it to be wondered that they have gone too far in very many cases, and that the leadership of such organization has in many instances been captured by designing men, who control the masses to accomplish selfish ends? whatever may have been the method of evolution, it is certain that the manufacturing operations of the present day have to meet with elements entirely antagonistic to their interests, and in very many ways antagonistic to the interests of the workingman. the members of many organizations, even of intelligent men, are blindly led by chiefs of various titles, of which perhaps the walking delegate is the most offensive one to reasonable people. this class of men claim the right to intrude themselves into the establishments owned by others, and on the most trivial grounds make demands more or less unreasonable, and order strikes and otherwise interfere with the work of manufacturers, much in the way that we have an idea that the agents of the barbarbous chieftains, feudal lords, and semi-civilized rulers collected taxes and laid burdens in earlier historical times. necessarily these men must use their power so as to insure its permanency. if strikes are popular, strikes must be ordered. if funds run low, excuses for strikes, it is believed, in many cases are sought, so as to stir the pulses of those who sympathize with the labor cause. co-operation has been suggested as a cure for the evil, and there are cases where it has apparently succeeded, in connection with the earlier forms of labor organization. the ambition of later labor leaders almost prevents this remedy being of effect. it may be possible still with very intelligent workmen, isolated from the large mass of workmen in the country towns, to feel an interest in co-operation; but such inducements, or the higher ones of personal kindness to employes or their families, are not of much effect in large manufacturing centers. as soon as dissatisfaction exists in one mill or manufactory, all similar employes are ordered out. the final result will be that combinations of employers must follow the combination of employes, and those who have always been strong in the past will be stronger in the future, as has appeared to be the case in many contests that have already taken place. if there are any real abuses of power by the employers, such as requiring work for unusual hours or at less than living rates, the first thing to do is to correct these abuses, so that complaints will not be upon a sound foundation. some men, when the labor epidemic strikes their places, have sufficient force of character and influence with their men to avert the blow for some time. others find it is policy to compromise with the representatives until a plan of action, conciliatory, offensive, or defensive, can be determined upon. the whole matter must be considered one of policy rather than of principles. the class of men to be dealt with do not talk principles except as an excuse to secure their ends. in spite of everything, there will be times when no compromise is possible and you will be called upon to take part in defending your employers' interests against what is called a "strike." you can do so with heart when you know the employes are all well paid, and particularly, as is frequently the case, when the labor organizers and walking delegates claim that some old, tried foreman shall be dismissed because they do like him, really because he has not been a tool in carrying out their plans, and they defiantly acknowledge that their war is against non-union labor, and that they have organized your men and forced a strike to require your establishment to become as it is called a "union shop." if your deluded employes were permitted simply to go away and let you alone, and you were permitted to employ others at the reasonable wages you were paying, the problem would be a simple one. the principal labor organizations claim that everything they do is by peaceable methods, but this, like many things said, is simply to deceive, for if you attempt to employ other assistants and carry on your business independently, you will surely find that well known roughs are assembled who never do anything without they are paid for it by somebody, that your men are assaulted by such persons, and while the labor organizers talk about peaceable methods and urge them aloud in public, in case one of the roughs is arrested, the loud talkers are the first to go bail for the defender, and you will feel morally sure that the sympathizing crowd with the roughs who make the assaults are all part of or tools of the organization. at such times, you will find your old employes standing around the street corners, persuading other men not to go to work and thus interfere with what are called the true interests of labor. any new employe who has to go in the street will be first met with inducements of other employment, with offers of money, afterward with threats, and, if opportunity occurs, with direct assault. all the features of persuasion, intimidation, and violence will be carried out as demanded, and strangers to everybody in the vicinity, but well known as experienced leaders in this kind of work in other places, be brought in to endeavor to make the strike a success. then, young men, is the time to show your pluck, and our experience is that educated young men will do so every time. they can be depended upon to go straight ahead with duty through every danger, bearing patiently everything that may be said, defending themselves with nature's weapons as long as possible, and without fear using reserve weapons in case real danger of life is imminent. in carrying through a very important strike against a mere desire to control and not to correct abuses, your speaker desires to pay the highest tribute to a number of educated young men, mostly from the technical schools, who fearlessly faced every danger, and by their example stimulated others to do their duty, and all participated in the results obtained by a great success. we would not by such references fire your hearts to a desire to participate in such an unpleasant contest. it is the duty of all to study this problem intelligently and earnestly, with a view of overcoming the difficulties and permitting the prosperity of the country to go on. while conciliation may be best at some times, policy at another, and resistance at another, we must also be thinking of the best means to prevent further outbreaks. it would seem to be true policy not to interfere with organization, but to try and direct it into higher channels. those of the humanitarians who claim that the disease will be rooted out eventually by a more general and better education are undoubtedly largely in the right, notwithstanding that some fairly educated men have acted against their best interests in affiliating with the labor organizations. it seems to the speaker that enough instances can be collected to show the utter folly of the present selfish system, based, as it is, entirely on getting all that is possible, independent of right in the matter, and by demanding equal wages for all men, tending to lower all to one common degradation, instead of rewarding industry and ability and advancing the cause of civilization. labor should not be organized for selfish ends, but for its own good, _so as to secure steady and permanent employment_, rather than prevent it by impracticable schemes and unwise methods, which will cripple manufacturers and all kinds of industry. the men should organize under the general laws of the state, so that their leaders will be responsible to the laws and can be indicted, tried, and punished in case they misappropriate funds or commit any breach of trust; and such laws should be amended if necessary, so that wise, responsible leaders of the organizations can contract to furnish labor for a certain time at a fixed price, when manufacturers can make calculations ahead as to the cost of labor the same as for the cost of material, and have such confidence that they will use all their energies to do a larger amount of business and benefit the workingman as well as themselves by furnishing steady employment. such a plan as is here outlined can readily be carried into effect by selecting better men as leaders. it is well known how well the organization known as the locomotive brotherhood is conducted, and it should be an example to others. it has had its day of dissensions, when the best counsels did not prevail, which shows that any organization of the kind, no matter how well conducted, may be diverted by its leaders into improper channels. when organized under the laws of the state and under by-laws designed to secure steady employment, rather than any artificial condition of things in regard to pay hours, and continuance of labor, the true interests of the workman will be advanced. it may be that some one of you will develop a talent in the direction of organization and be the means of aiding in the solution of this great problem. please think of the matter seriously, watch the law of evolution while you are advancing your professional knowledge, and if the opportunity offers, do all you can to aid in a cause so important and beneficent. one writer has criticised the technical schools because they do not teach mechanical intuition. the schools have enough to do in the time available if they teach principles and sufficient practice to enable the principles to be understood. the aptitude to design, which must be what is meant by mechanical intuition, requires very considerable practical experience, which you will readily learn if you do not keep yourself above it. if you have used your leisure hours to study why a certain piece of mechanism was made in a certain way rather than in another; if you have wondered why one part is thick in one place rather than in another, apparently in defiance of all rules of the strength of material; if you have endeavored to ascertain why a particular device is used rather than another more evident one; if you have thought and studied why a boss is thrown in here and there in designs to receive bolts or to lengthen a journal, and if you have in your mind, by repeated observation, a fair idea of how work is designed by other people, the so-called _mechanical intuition_ will be learned and found to be the _combination of common sense and good practice_. you will observe that some details have been copied for years and years, although thoughtful men would say they are not the best, simply because they are adapted to a large amount of work already done. this is particularly true of the rolling stock on railroads. the cost of a change in starting in a new country might be warranted, but it practically cannot be done when the parts must interchange with so much work done in other parts of the country. you will find in other cases that the direct strain to which a piece of mechanism is subjected is only one of the strains which occur in practice. a piece of metal may have been thickened where it customarily broke, and you may possibly surmise that certain jars took place that caused such breakages, or that particular point was where the abuse of the attendant was customarily applied. wherever you go you will find matters of this kind affecting designs staring you in the face, and you will soon see why a man who has learned his trade in the shop, and from there worked into the drawing room with much less technical information than you have, can get along as well as he does. reserve your strength, however. your time will come. whenever there is a new departure to be taken, and matters to be worked out from the solid which require close computation of strains or the application of any principles, your education will put you far ahead, and if you have, during the period of what may be called your post-graduate course, which occurs during your early introduction into practical life, been careful to keep your eyes and ears open so as to learn all that a man in practical life has done, you will soon stand far ahead. reference was made to the use of leisure hours. leisure hours can be spent in various ways. for instance, in studying the composition and resolution of forces and the laws of elasticity in a billiard room, the poetry of motion, etc., in a ball room, and the chemical properties of various malt and vinous extracts in another room; but the philosophical reason why certain engineering work is done in the way it is, and the proper way in which new work shall be done of a similar character and original work of any kind carried on, can only be learned by cultivating your powers of observation and ruminating on the facts collected in the privacy of one's own room, away from the allurements provided for those who have nothing to do. no one would recommend you to so separate yourself from the world as to sacrifice health and strength, or to become a recluse, even if you did learn all about a certain thing. remember, however, that the men who have accomplished most in this world worked the longest hours, and any one with a regular occupation must utilize his leisure hours to obtain prestige. the difference between one man and another of the same natural ability lies entirely in the amount of his information and the facility with which he can use it. life is short, and you must realize that now is your opportunity. if any diversion in the way of pleasure or even certain kinds of congenial work is offered, consider it in connection with the question, "will this be conducive to my higher aim?" this implies that you have a higher aim; and if you have it, and weigh everything in this way, you will find that every moment of exertion adds something to your storehouse of information and brings you nearer to the accomplishment of that higher aim. in closing, we thank the ladies and gentlemen present for their close attention to details of special interest only to those engaged in technical study or practice. we congratulate you, young gentlemen of the class of ' , for the success you have thus far obtained, and trust that you will persevere in well doing and win greater success in the future. we need hardly state that all that has been said was in a spirit of kindness, and we feel assured that much of it has been seconded by your parents, to whom no less than to all parents here present off or on the stage, the speaker not excepted, a serious, thoughtful problem has been, still is, and will continue to be to many, "what shall we do with our boys."--_stevens indicator._ * * * * * heating marine boilers with liquid fuel. we were recently witness of an experiment made at eragny conflans on the steam yacht flamboyante. it was a question of testing a new vaporizer or burner for liquid fuel. the experiment was a repetition of the one that the inventor, mr. g. dietrich, recently performed with success in the presence of admirals cloue and miot. the flamboyante is ft. in length, ft. in width, draws ft. of water, and has a displacement of tons. she is provided with a double vertical engine supplied by a belleville boiler that develops horse power. the screw makes revolutions per minute, and gives the yacht a speed of ½ knots. mr. dietrich's vaporizer appears to be very simple, and has given so good results that we have thought it of interest to give our readers a succinct description of it. in this apparatus, the inventor has endeavored to obtain an easy regulation of the two essential elements--naphtha and steam. fig. represents the apparatus in section. the steam enters through the tubulure, a, and finds its way around the periphery of a tuyere, d. it escapes with great velocity, carries along the petroleum that runs from two lateral tubulures, b (fig. ), and throws it in a fine spray into the fireplace, through the nozzle, c (fig. ), which is flattened into the shape of a fan opened out horizontally. the mixture at once ignites in contact with the hot gases, and gives a beautiful, long, clear flame. the air necessary for the combustion is sucked through the interior of the nozzle, h, which is in front of the tuyere. it will be seen that the current of steam can be regulated by moving the tuyere, d, from or toward the eduction orifice. this is effected through a maneuver of the hand wheel, f. in the second place, the flow of the petroleum is made regular by revolving the hand wheel, g, which gives the piston, o, a to and fro motion in the tuyere, d. [illustration: fig. --the dietrich petroleum burner.] the regulation may be performed with the greatest ease. it is possible to instantly vary, together or separately, the steam and the petroleum. under such circumstances, choking is not to be feared at the petroleum orifice, where, according to experiment, the thickness of the substance to be vaporized should not be less than . of an inch. the petroleum might evidently be made to enter at a and the steam at b; but one of the conclusions of the experiments cited is that the performance is better when the jet of steam surrounds the petroleum. it will be understood, in fact, that by this means not a particle of the liquid can escape vaporization and, consequently, combustion. moreover, as the jet of petroleum is completely surrounded by steam its flow can be increased within the widest limits, and this, in certain cases, may prevent an obstruction without much diminishing the useful effect of the burner. the apparatus is easily and rapidly taken apart. it it is only necessary to remove the nozzle, c, in order to partially clean it. it would even seem that the cleaning might be done automatically by occasionally reversing the flow of the steam and petroleum. however efficacious such a method might prove, the apparatus as we have described it can be very easily applied to any generator. fig. represents it as applied to the front of a furnace provided with two doors. a metallic box, with two compartments, is placed on one side of the furnace, and is provided with two stuffing boxes that are capable of revolving around the steam and petroleum pipes. the latter thus form the pivots of the hinge that allows of the play of the vaporizers and piping. [illustration: fig. --the burner applied to the furnace of a boiler.] it was in this way that mr. dietrich arranged his apparatus in an experiment made upon a stationary boiler belonging to a mr. corpet. the experiment was satisfactory and led to the adoption of the arrangement shown in fig. . the fire bridge is constructed of refractory bricks, and the majority of the grate bars are filled in with brick. the few free bars permit of the firing of the boiler and of access of air to the interior of the fire box. under such circumstances, the combustion is very regular, the furnace does not roar, and the smoke-consuming qualities are perfect. [illustration: fig. --application of the burner to a return flame boiler.] in the experiment on the flamboyante, the boiler was provided with but one apparatus, and the grate remained covered with a layer of ignited coal that had been used for firing up in order to obtain the necessary pressure of steam to set the vaporizer in operation. this ignited coal appeared to very advantageously replace the refractory bricks, the role of which it exactly fulfilled. it has been found well, moreover, to break the flames by a few piles of bricks in the furnace, in order to obtain as intimate a mixture as possible of the inflammable gases. it is to be remarked that firing up in order to obtain the necessary steam at first is a drawback that might be surmounted by using at the beginning of the operation a very small auxiliary boiler. the main furnace would then be fired by means of say a wad of cotton. but, in current practice, if a grate and fire be retained, the firing will perhaps be simpler. with but one apparatus, the pressure in the flamboyante's boiler rose in a few minutes from to pounds, and about a quarter of an hour after leaving the wharf the apparatus had been so regulated that there was no sign of smoke. this property of the dietrich burner proceeds naturally from the use of a jet of steam to carry along the petroleum and air necessary for combustion. it is, in fact, an orvis smoke consumer transformed, and applied in a special way. it must be added that the regulating requires a certain amount of practice and even a certain amount of time at every change in the boat's running. so it is well to use two, and even three, apparatus, of a size adapted to that of the boiler. the regulation of the furnace temperature is then effected by extinguishing one or two, or even three, of the apparatus, according as it is desired to slow up more or less or to come to a standstill. the oil used by mr. de dosme on his yacht comes from comaille, near antun. the price of it is quite low, and, seeing the feeble consumption (from to lb. for the yacht's boiler), it competes advantageously with the coal that mr. de dosme was formerly obliged to use.--_la nature._ * * * * * [continued from supplement, no. , page .] the change of gauge of southern railroads in .[ ] [footnote : a paper read before the western society of engineers, june , .] by c.h. hudson. many of the wheels that were still in use with the long hub were put into a lathe, and a groove was cut an inch and a half back from the face, leaving our cast collar, which was easily split off as before. (fig. .) with tender wheels, as with our car wheels, the case was different. originally, the axle for the ft. gauge was longer than for the ft. in.; but latterly the ft. roads had used a great many master car builders' axles for the ft. in. gauge, namely, ft. ¼ in. over all, thus making the width of the truck the same as for ft. in. gauge. to do this a dished wheel, or rather a wheel with a greater dish by ½ in. than previously used, was needed, so that the tread of the wheel could be at its proper place. (see fig. .) there were, of course, many of the wheels with small dish and long axles still in use. their treatment, however, when the day of change came, did not vary from that of the short axle. [illustration: fig. and fig. ] it had been the rule for some years that all axles should be turned back ½ in. further than needed; but unfortunately the rule had not been closely followed, and many were found not to be so turned. to make the matter worse, quite a number of the wheels were found to have been counterbored about ½ in. deep at the back end, and the axle turned up to fit this counterbore; a good idea to prevent the running in, in case the wheel worked loose, but bad from the standpoint of a change of gauge. in such cases the wheels had to be started off before the axle could be turned back, so that the wheels could be pushed on in their proper position. (fig. .) [illustration: fig. ] if the work was done where they had a lathe large enough to swing a pair of wheels, they were pressed off but half an inch, the wheels swung in the lathe, the axles turned back ½ in., and the wheels then pressed on in. or ½ in. inside of their first position. where no large lathe was in use, the wheels came entirely off before the axles could be turned back. the work in the former case was both the quicker and the cheaper. where the large lathes were used they were either set down into the floor, so a pair of wheels would easily roll into place, or a raised platform was put before the lathe, with an incline up which the wheels were rolled and then taken to the lathe. these arrangements were found much quicker and cheaper than to hoist the wheels up, as is usually done. in pressing the wheels on, where the axles had previously been turned back, much trouble was at first experienced because of the rust that had gathered upon the turned part behind the wheel, forming a ridge over or upon which the wheel must be pushed. some of the roads, at the start, burst or per cent. of the wheels so pressed on. by saturating this surface with coal oil, however, it was found that the rust was easily removed and little trouble was had. it was found, sometimes, that upon axles newly turned back a careless workman would leave a ridge at the starting point of the turning. frequently also the axles were a little sprung, so that the new turning would be a little scant upon one side when compared with the old surface, and upon the opposite side a little full. as an indication that these difficulties were overcome as they appeared, i will say that upon our line only wheels burst out of nearly , pressed on--an exceedingly small percentage. after the change upon the early roads they were troubled for weeks with hot boxes, caused, as we believed, by the changing of brasses. a brass once fitted to a journal will work upon it without trouble, but when placed upon some other journal will probably not fit. if the journal had been worn hollow (and it was surprising to see how many were so worn), the brass would be found worn down to fit it. (see fig. . exaggerated, of course.) [illustration: fig. and fig. ] the next wheel may have an axle worn little or none. (see fig. ) now, if these brasses are exchanged, we have the conditions as shown in figs. and , and we must expect they will heat. the remedy was simply to keep each brass upon its own journal. to do this the brasses were fastened to the axle by a piece of small wire, and went with it to the lathe and press. when its truck was reached, the brass was there with its journal. worn-out brasses, of course, could not be put in, and new ones were substituted. the little trouble from that source that followed the change showed the efficacy of the remedy. [illustration: fig. and fig. ] the manner in which the tires of engines were to be changed, when the final day came, was a serious question. the old-fashioned fire upon the ground could not be thought of. the m. & o. had used a fire of pine under the wheel, which was covered by a box of sheet iron, so arranged that the flame and heat would be conveyed around the tire, and out at an aperture at the top. (fig. .) many thought this perfect, while others were not satisfied, and began experiments for something better. a device for using gas had been patented, but it was somewhat complicated, as well as expensive, and did not meet with general favor. a very simple device was soon hit upon. a two inch pipe was bent around in a circle a little larger than the outer rim of the wheel. holes / in. in diameter and or in. apart were drilled through the pipe on the inside of the circle. to this pipe was fastened another with a branch or fork upon it. to one branch or fork was connected a gas pipe from the meter, while to the other was connected a pipe from an air pump. with the ordinary pressure of city gas upon this pipe it was found that the air pump must keep an air pressure of pounds, that the air and gas might mix properly at the branch or fork, so we could get the best combustion and most heat from our "blowpipe," for such it was. (fig. .) [illustration: fig. and fig. ] we were able to heat a tire so it could be moved in ten to twenty minutes, and the machine may be said to have been satisfactory. gas, however, was not to be had at all places where it would be necessary to change tires, and the item of cost was considerable. to reach a result as good, if possible, experiments were begun with coal oil (headlight oil). they were crude and unsatisfactory at first, but soon success was reached. a pipe was bent to fit the lower half of a wheel pretty closely and then turned back under itself about the diameter of the pipe distant from it. this under part had holes / in. diameter and or in. apart drilled upon its upper side or under the upper pipe. connected with the upper pipe at its center was a pipe which ran to one side and up to the can containing the kerosene. between the can and the pipe under the wheel was a stop cock, by which the flow of oil could be controlled. [illustration: fig. ] to use the device, open the cock and let a small amount of oil flow; apply fire to the pipe under the wheel, and the oil in the upper pipe is converted into gas, which flows out of the small holes in the lower pipe, takes fire, and heats not only the tire, but the upper pipe, thus converting more oil into gas. we had here a lot of blue flame jets and the same result as with gas, but at less cost. we had also a machine that was inexpensive and easily handled anywhere. boxes were placed over the upper parts of the wheels, that the heat might pass closely to the tire. this device was extensively used by our people, and with great satisfaction. in one way care had to be taken, viz.: that in starting the fire it did not smoke and cover the tire with carbon or "lampblack," which is a non-conductor of heat. experiments were made with air forced through gasoline, and with oil heated in a can to form gas. there was more danger in either of these than with our blowpipe device, and no better results were obtained, though the cost was greater. with the change of the wheels, the brakes had to be changed the same amount, that is, each one set in ½ in. this it was thought would either require new hangers or a change in the head or shoe in some way. we found that the hangers could easily be bent without removal. fig. shows three hangers after passing through the bending process. a short lever arranged to clasp the hanger just below the point, a, was the instrument; a forked "shore" is now placed, with the fork, against the point, a, and the other end against the car sill; press down on the lever and you bend the hanger at a; lower the lever to a point just below b, reverse the process, and you have the bend at b; the whole thing taking less than two minutes per hanger. a new bolt hole, of course, has been bored in the brake beam ½ in. inside the old hole. it takes but a short time after this to change the position of the head and shoe. [illustration: fig. ] before the day of change, a portion of the spikes were drawn from the inside of the rail to be moved, and spike set in. inside of the rail. as a rule two spikes were drawn and the third left. at least every third spike was set for the new gauge, and in some cases every other one. there were several devices with which to set the spike. a small piece of iron in. wide was common, and answered the purpose well. this had a handle, sometimes small, just large enough for the hand to clasp, while others had a handle long enough for a man to use it without stooping down. (see figs. and .) another device is shown in fig. , so arranged that the measurements were made from the head of the other rail. this was liked best, and, it is thought, gave the best results, as the moved rail was more likely to be in good line than when the measurements were taken from the flange. [illustration: fig. , fig. and fig. ] it was intended that great care should be taken in driving the spikes, that they were in the proper place, square with the rail, and left sticking up about an inch. the ties, of course, were all adzed down before the day of change. "handspikes" were originally used to throw the rails, as were lining bars. we found, however, that small "cant hooks" were more easily handled and did better work. the first were made like fig. , with a spike in the end of a stick, while the hook was fastened with a bolt about or inches above the foot. [illustration: fig. and fig. ] we afterward made them of a ¼ in. rod, ½ ft. long, pointed at one end, with a ring shrunk on ft. from the bottom. then the hook was made with an eye, as shown in fig. , which slipped down over the top of the main rod. this was simple and cheap, and the iron was to be used for repair purposes when this work was done. upon the system with which the writer was connected we had some branches where we could experiment upon the moving of the rail. between selma and lauderdale the traffic was light, and at lauderdale it connected with the mobile & ohio railroad, which was narrow, and to which all freight had to be transferred, either by hoisting the cars or by handling through the house. by changing our gauge we would simply change the point of transfer to selma. here was a chance to experiment upon one hundred miles and cause little trouble to traffic. we could see the practical workings of our plans, and, at the same time, leave less to do on the final day. upon the th of april we did this work. it had been our plan to do it somewhat earlier, but floods prevented. most of the rail was old chair iron, short, and consequently more time was used in making the change than would have been required had our work been on fishplate rail. our sections here were about eight miles long, and we arranged our men on the basis blocked out by the committee, viz., to men to the section, consisting of spike pullers, throwing rails, spikers, to push the cars and carry water. we soon found ft. cars useless, and threw them into the ditch to be picked up at some future time. the men were spread out so as not to be in each other's way, and when the organization was understood and conformed to, it worked well. one gang changed miles in hours and minutes, including a number of switches. we found, however, and it was demonstrated still more strongly on later work, that after or miles the men began to lag. we believed we had the best results when we had sections of about that length. it was arranged that two sections, alternately, commenced work together at one point, working from each other and continuing until the force of another section was met, working from the opposite direction. the foreman in charge was expected to examine the work and know that all was right. the push car which followed was a good test as to gauge. a work train was started from each end with a small force ( or men) to run over the changed track. this train, of course, had been changed on a previous day to be ready for this work. if a force was overtaken by this train with its work not done, the men on the train were at once spread out to aid in its completion. this done, the train ran on. not until this was done was a traffic train allowed to pass over the track. the same rule was followed upon all the work. upon the final day it was required that upon all high trestles and in tunnels the track should be full-spiked before being left or a train let over. this took extra time and labor, and possibly was not necessary; but it was a precaution on the side of safety. upon the day of the change of the alabama central division (selma to lauderdale), superintendents of other divisions, with their road masters, supervisors, master mechanics and many section foremen, were sent over to see the organization and work and the preparations that had been made. many of them lent a helping hand in the work. they saw here in practice what had only been theory before. about a week before the general change that portion of the road between rome, ga., and selma, ala., about miles, was changed, and again men from other divisions were sent to see and aid in the work. so when the final day came, the largest possible number of men were able to work understandingly. on the last day of may the memphis & charleston, knoxville & ohio, and north carolina branch were changed, and on june the line from bristol to chattanooga and brunswick. other roads changed their branch lines a day or two before the st of june; but the main lines, as a rule, were changed on that day. it was a small matter to take care of the cars and arrange the train service so there should be no hitches. it was not expected that connections would move freight during the hours prior to the change, and these days were spent in clearing the road of everything, and taking the cars to the points of rendezvous. all scheduled freight trains were abandoned on the day prior to the change, and only trains run _to_ such points. upon the east tennessee system these points were knoxville, rome, atlanta, macon, huntsville, and memphis, and to these points all cars must go, loaded or empty, and there they were parked upon the tracks prepared for the purpose. passenger trains were run to points where it had been arranged to change them, generally to the general changing point. most of the southern roads have double daily passenger service. upon all roads one of these trains, upon the day of change, was abandoned, and upon some all. some, even, did not run till next day. we were able to start the day trains out by or o'clock a.m., and put them through in fair time. of course, no freights were run that day, and the next day was used in getting the cars which had been changed out of the parks and into line. so our freight traffic over the entire south was suspended practically three days. the work of changing was to commence at : a.m., but many of the men were in position at an earlier hour, and did commence work as soon as the last train was over, or an hour or so before the fixed time. half-past three a.m., however, can be set down as the general hour of commencement. for five or six hours in the cool morning the work went on briskly, the men working with much more than ordinary enthusiasm. but the day was warm, and after or a.m. it began to lag. all was done, however, before the day was over, and safe, so that trains could pass at full speed. the men all received $ . for the work, whether it was finished early or late in the day, and were paid that afternoon as soon as the work was done. tickets were given the men, which the nearest agent paid, remitting as cash to the treasurer. on some lines it was deemed best to offer prizes to those who got through first. reports showed some very early finishes. but the facts seem to have been that under such encouragement the men were apt to pull _too many_ spikes before the change and put _too few_ in while changing. they were thus reported through early, but their work was not done, and they took great chances. it was by most considered unwise to offer such prizes, preferring to have a little more time taken and be sure that all was safe. such lines seemed to get their trains in motion with as much promptness as others. this, with freedom from accident, was the end sought. it was found after the work had been done that there had been little inaccuracies in driving the gauge spike, to which the rail was thrown, probably from various causes. the rail to be moved may not always have been exactly in its proper place, and then the template in the hurry may not have been accurately placed, or the spike may have turned or twisted. whatever was the cause, it was found that frequently the line on the moved side was not perfect, and, of course, many spikes had to be drawn and the rail lined up and respiked. the more careful the work had been done, the less of this there was to do afterward. with rough track this was least seen. the nearer perfect, the more noticeable it was. of course, we all planned to get foreign cars home and have ours sent to us. but when the interchange stopped, we found we had many foreign cars, which, of course, had to be changed. this subject had come up in convention and it had been voted to charge three dollars per car when axles did not need turning, and five dollars where they did. by comparison with the cost of changing, as shown in this paper, it will be seen that to our company, at least, there was no loss at these figures. the following tables will explain the work done upon the louisville & nashville and east tennessee, virginia & georgia systems. it is to be regretted that the writer has not at hand information regarding other roads, that fuller statements and comparisons might be made and the showings be of greater value. the figures of the mobile & ohio are added, having been compiled from the annual report of that road. mobile & ohio railroad. (_compiled from annual report._) ________________________________________________________________________ | | | | | | | number | cost of | cost of | total |average| |changed.| labor. | material | cost. | cost. | |________|__________|__________|__________|_______| | | | | | | engines and tenders. | |$ , . |$ , . |$ , . |$ . | pass., bag., ex. cars.| | . | . | . | . | freight cars, , . }| , ½ | , . | . | , . | . | freight trucks, ½.}| | | | | | lever and push cars. | | , . | . | , . | . | | | | | | | | miles. | | | | | track (inc. sidings). | . | , . | , . | , . | . | bridges. | . | , . | . | , . | . | track tools. | . | . | , . | , . | . | shop tools. | . | . | , . | , . | . | temp. side tracks. | . | , . | . | , . | . | switching cars. | | , . | . | , . | | car hoists. | | , . | , . | , . | | |________|__________|__________|__________|_______| | | | | | | total cost. | |$ , . |$ , . |$ , . | | total average cost | | | | | | per mile. | | | | |$ . | ______________________|________|__________|__________|__________|_______| louisville & nashville railroad. (_compiled from annual report._) miles of track--main line , . --side track . ------- , . cost track. total. per mile. section labor--before day of change $ , . --on day of change , . --after day of change , . ---------- $ , . $ . carpenter labor , . . spikes , . . switches , . . tools , . . hand cars and sundries , . . ----------- ------ total $ , . $ . _equipment._ average number. total. cost. locomotives $ , . $ . cars ( of these passenger-- . %) , , . . ----------- -------- total cost $ , . total average cost per mile $ . east tennessee, virginia & georgia system. __________________________________________________________________________ | | | | | | | number | cost of | cost of | total |average| | changed.| labor. | material | cost. | cost. | |_________|__________|__________|___________|_______| | | | | | | engines and tenders. | |$ , . |$ , . |$ , . |$ . | pass., bag., and mail | | | | | | cars. | | . | . | . | . | freight cars and | | | | | | cabooses. | , | , . | , . | , . | . | m. of w. cars. | | , . | . | , . | . | | miles | | | | | | track. | | | | | track (inc. sidings). | , . | , . | , . | , . | . | bridges. | , . | , . | . | , . | . | track tools. | , . | . | , . | , . | . | storage tracks, inc. | | | | | | taking up. | . | , . | , . | , . | . | shop tools. | | . | , . | , . | | |_________|__________|__________|___________|_______| | | | | | | total cost. | |$ , . |$ . . |$ , . | | total average cost | | | | | | per mile. | | | | |$ . | ______________________|_________|__________|__________|___________|_______| axles condemned wheels condemned wheels burst new axles used , new wheels used , axles turned back , wheels pressed on without turning axle , new brasses used , cars narrowed (not including lever or push cars) , engines narrowed average cost of new centers and crank pins, etc $ . average cost of cutting off hub and pressing wheels and new pins . average cost of pressing old tires on old centers . average cost of pressing old tires on broad centers . average cost of labor putting on new tires . comparative statement of average cost of various items of work. __________________________________________________________________________ | | | | | | m. & | l. & | e.t., v.|average. | | o. r.r. | n. r.r. |& g. r.r.| | |_________|_________|_________|_________| | | | | | engines and tenders--per engine | $ . | $ . | $ . | $ . | pass., bag., and ex. cars--per car| . |[ ] . | . | . | freight cars, per car | . |[ ] . | . | . | m. of w. cars, per car | . | . | . | . | track (inc. sidings bridges, | | | | | etc.), per mile | . | . | . | . | track tools, per mile | . | . | . | . | temporary side tracks, per mile | . | | . | . | |_________|_________|_________|_________| total per mile of track, inc. | | | | | sidings | $ . | $ . | $ . | $ . | __________________________________|_________|_________|_________|_________| [footnote : expense not divided as between passenger and freight cars.] [footnote : . per cent. passenger, baggage, and express cars, . per cent. freight cars.] note--since the preparation of this paper the general manager of the norfolk & western railroad has kindly furnished the following items of expense for that line: ___________________________________________________________________ | | | | | no. | cost. | average | | | | cost. | |_________|____________|_________| | | | | engines and tenders | | $ , . | $ . | cars (all kinds) | , | , . | . | track, miles (including sidings) | . | | | labor | | , . | | tools and supplies | | , . | | changing m. of w. equipment | | . | | switches | | . | | spikes | | , . | | | | ---------- | | total track | | $ , , | . | | | ========== | | total | |$ , . |---------| total average cost per mile | | | $ . | __________________________________|_________|____________|_________| and the superintendent of the s.f. & w. r.r. has also furnished the expenses for that road: ___________________________________________________________________ | | | | no. | average | | | cost. | |__________|_________| | | | engines and tenders | | $ . | cars (passenger) | | . | cars (freight) | , | . | track, including sidings | . | . | ______________________________________________|__________|_________| nothing was said about shop or other tools, storage tracks, or changing of maintenance of way equipment. comparative statement of average cost of labor of various items of work. _________________________________________________________________ | m. & | l. & | e.t., v. | | | o. r.r. | n. r.r.| & g. r.r.| average| |_________|________|__________|________| | | | | | engines and tenders. | $ . }| | {$ . | $ . | pass., bag., and ex cars | . }| not | { . | . | freight cars | . }| divided| { . | . | m. of w. cars | . }| | { . | . | miles track (including | | | | | sidings, bridges, etc.) | . | $ . | . | . | track tools, per mile | . | not | . | . | temporary tracks | . | divided| . | . | |_________|________|__________|________| | | not | | | total per mile of track | $ . | divided| $ . | $ . | __________________________|_________|________|__________|________| comparative statement of average cost of material of various items of work. _________________________________________________________________ | m. & | l. & | e.t., v. | | | o. r.r. | n. r.r.| & g. r.r.| average| |_________|________|__________|________| | | | | | engines and tenders. | $ . }| | { $ . | $ . | pass., bag., and ex cars | . }| not | { . | . | freight cars | . }| divided| { . | . | m. of w. cars | . }| | { . | . | miles track (including | | | | | sidings, bridges, etc.) | . | $ . | . | . | track tools, per mile | . | not | . | . | temporary tracks | . | divided| . | . | __________________________|_________|________|__________|________| | | not | | | total per mile of track | $ . | divided| $ . | $ . | __________________________|_________|________|__________|________| summary of statements of l.& n. and e.t., v.& g. railways. the mileage changed of the l&n. and e.t., v.& g. systems combined aggregates , miles. the total cost of these two roads. $ , . or an average per mile of . total miles changed was about , miles. which would give total cost, at same rate. $ , , we should really add to this a large sum for the great number of new locomotives which were purchased to replace old ones, that could not be changed, except at large cost, and which, when done, would have been light and undesirable. upon the basis of the work done upon the l. & n. and e.t., v. & g. systems, which, combined, cover about one-fourth the mileage changed, we have made the following estimates, which will, perhaps, convey a better idea of the extent of the work than can be obtained in any other way: miles of track changed, about , locomotives changed, about , cars (pass, and freight) changed, about , new axles used, about , new wheels used, about , axles turned back, about , wheels pressed on without turning axles, about , new brasses used, about , kegs of spikes used, about , cost of material used, about $ , cost of labor, about , total cost of work, about , , amount expended on equipment, about , amount expended on track, about , amount expended on track on day of change in labor, about , the work was done economically, and so quietly that the public hardly realized it was in progress. to the casual observer it was an every day transaction. it was, however, a work of great magnitude, requiring much thought and mechanical ability. that it was ably handled is evidenced by the uniform success attained, the prompt changing at the agreed time, and the trifling inconvenience to the public.--_jour. assn. engineering societies._ * * * * * torpedo boats for spain. in our present issue, on page , we give illustrations of two torpedo boats, the azor and halcon, which have lately been constructed by messrs yarrow & co., of poplar, for the spanish government. they are ft. in length by ft. beam, being of the same dimensions as no. torpedo boat, lately completed by the above firm for the admiralty, which is the largest and fastest torpedo-boat in the british navy. [illustration: torpedo boats for the spanish government.] the general arrangement of these torpedo boats is sufficiently clear from the illustrations to need but little description. suffice it to say that the engines are of the triple compound type, capable of indicating , horse power, steam being supplied by one large locomotive boiler, which our readers are already aware is in accordance with the usual practice of the makers, as, by using a single boiler, great simplification of the machinery takes place, and considerably less room is occupied than if two boilers were adopted. it is worthy of record that although in some torpedo boats, and indeed in a great number of them, trouble has been found with the locomotive type of boiler, still we have no hesitation in saying that this is due either to defective design or bad workmanship, and that, if properly designed and constructed, such difficulty does not occur. and it is a fact that messrs. yarrow & co. have already constructed a great number of locomotive boilers of the exceptional size adopted in these two spanish boats, and they have turned out in every respect, after actual service, perfectly satisfactory. the forward part of the boat is provided with two torpedo-ejecting tubes, as usual, and near the stern, on deck, it is proposed to place turntables, with two torpedo guns for firing over the sides, as already adopted by several governments. the trials of the azor took place about two months since, giving a speed during a run of two hours and three quarters, carrying a load of tons, of knots (over ½ miles) per hour. since her trial she has steamed out to spain, having encountered, during a portion of the voyage very bad weather, when her sea going qualities were found to be admirable. the halcon, whose official trials took place lately, obtained a speed of . knots, carrying a load of tons. it may be remarked that a speed of knots, in a boat only ft in length, under the spanish conditions of trial, is by far the best result that has ever been obtained in a vessel of these dimensions there is, however, no doubt that had the length of the boat been greater, a still higher speed would have been obtained but it was desired by the authorities to keep within the smallest possible dimensions, so as to expose as little area as practicable to the fire of the enemy, it being clearly evident that this is a consideration of the first importance in an unprotected war vessel. in conclusion, we would add that the hulls of these two spanish boats are of much greater strength of construction than is usually adopted in torpedo boats, it having been found that for the sake of obtaining exceptional speeds, strength sufficient for actual service has often been injudiciously sacrificed and, judging from the numerous accidents which took place at the recent trials off portland, we have no doubt that in the future naval authorities will be quite ready and willing to sacrifice a little speed so as to obtain vessels which are more trustworthy. the necessity for this, we feel convinced, will be conclusively shown if ever torpedo boats are engaged in actual warfare, and this not only as regards strength of hull, but also as regards the machinery, which at present is only capable of being handled successfully by men of exceptional training, who in times of war would not be readily procured--_the engineer._ * * * * * the spanish cruiser reina regente in our supplement, no. we gave an illustration of this ship, with some particulars. the interest expressed in naval circles for further information induces us to give still further engravings of this remarkable vessel, with additional information, for which we are indebted to the _engineer_. [illustration: the new spanish war ship reina regente.] we gave recently a short account of two of the trials of this vessel, and we are, by the courtesy of the builders--messrs. thomson, of clydebank--enabled to lay further particulars before our readers this week. we give herewith engravings of the vessel, which will illustrate her salient points. the principal dimensions are as follows. length on water line, ft., breadth, ft. in., depth moulded, ft. in., normal displacement, , tons, deep load displacement, , tons. we have before informed our readers that this vessel was designed by messrs. thomson, in competition with several other shipbuilding firms of this and other countries, in reply to an invitation of the spanish government for a cruiser of the first class. the design submitted by the builders of the reina regente was accepted, and the vessel was contracted to be built in june of last year. the principal conditions of the contract were as follows. the ship to steam at a speed of ½ knots for four runs on the mile and for two hours continuously afterward. she was further to be capable of steaming for six hours continuously at a speed of ½ knots, without any artificial means of producing draught. she was also to be capable of steaming a distance of at least , knots for tons of coal, at some speed over knots, to be chosen by the builders. over the length of her machinery and magazine spaces she was to have a sloping deck extending to ft. below the water line at the side, and formed of plates ¾ in. thick. this deck was to extend to about ft. above the water line, and the flat part to be - / in. thick. beyond the machinery and magazine spaces, the deck was to be gradually reduced to in. thick at the ends. this deck is intended to protect the vitals of the ship, such as boilers, engines, powder magazines, steering gear, etc., from the effects of shot and shell, but the floating and stability maintaining power of the ship was to be dependent upon a similar structure raised above this protective deck to a height of about ft. above the water. this structure is covered by a water tight deck known as the main deck of the ship, on which the cabins and living spaces are arranged. the space between the main and protective deck is divided, as may be seen by reference to the protective deck plan, into many strong, water tight spaces, most of which are not more than about cubic feet capacity. the spaces next to the ship's side are principally coal bunkers, and may, therefore, exclude largely any water that should enter. the first line of defense is formed inside these coal bunkers by a complete girdle of coffer dams, which can be worked from the main deck. these it is intended to fill with water and cellulose material, and as they are also minutely subdivided, the effects of damage by shot and consequent flooding may be localized to a considerable extent. the guns of the ship are to consist of four centimeter hontorio breech loading guns on vavasseur carriages, six centimeter guns, eight pounder rapid firing, and eight or ten small guns for boats and mitrailleuse purposes, four of which are in the crow's nests at the top of the two masts of the ship. we may remark in passing that the builders saw their way at an early period of the construction to suggest an addition to the weight of the large sized guns, and there will actually be on the ship four centimeter guns, instead of four centimeter. the vessel was to carry five torpedo tubes, two forward in the bow, one in each broadside, and one aft. all these tubes to be fixed. to fulfill the speed condition, four boilers were necessary and two sets of triple expansion engines, capable of developing in all , horse power. [illustration: protective deck plan.] now that the vessel has been completely tried, the promises by the builders may be compared with the results determined by the commission of spanish officers appointed by the government of spain to say whether the vessel fulfilled in all respects the conditions laid down in the contract. the mean speed attained for the two hours' run was . knots, as compared with . guaranteed, but this speed was obtained with , horse power instead of the , which the machinery is capable of developing. the officers of the spanish commission were anxious not to have the vessel's machinery pressed beyond what was necessary to fulfill the speed conditions of the contract; but they saw enough to warrant them in expressing their belief that the vessel can easily do twenty-one knots when required, and she actually did this for some time during the trial. during the natural draught trial the vessel obtained a mean speed of . knots, on an average of ¾ revolutions--the forced draught having been done on an average of ½ revolutions. the consumption trial, which lasted twelve hours, was made to determine the radius of action, when the ship showed that at a speed of . knots she could steam a distance of , knots. further trials took place to test the evolutionary powers of the vessel, though these trials were not specified in the contract. the vessel, as may be seen from the engravings, is fitted with a rudder of a new type, known as thomson & biles' rudder, with which it is claimed that all the advantage of a balanced rudder is obtained, while the ship loses the length due to the adoption of such a rudder. it is formed in the shape of the hull of the vessel, and as the partial balance of the lower foreside gradually reduces the strains, the rudder head may be made of very great service. as a matter of fact, this rudder is ft. in area, and is probably the largest rudder fitted to a warship. the efficiency of it was shown in the turning trials, by its being able to bring the vessel round, when going at about nineteen knots, in half a circle in one minute twenty-three seconds, and a complete circle in two minutes fifty-eight seconds, the diameter of the circle being yards. this result, we believe, is unrivaled, and makes this vessel equal in turning capabilities to many recent warships not much more than half her length. * * * * * film negatives.[ ] [footnote : a communication to the birmingham photographic society.] having had a certain measure of success with eastman stripping films, i have been requested by your council to give a paper this evening dealing with the subject, and particularly with the method of working which my experience has found most successful. in according to their request, i feel i have imposed upon myself a somewhat difficult task. there is, undoubtedly, a strong prejudice in the minds of most photographers, both amateur and professional, against a negative in which paper is used as a permanent support, on account of the inseparable "grain" and lack of brilliancy in the resulting prints; and the idea of the paper being used only as a temporary support does not seem to convey to their mind a correct impression of the true position of the matter. it may be as well before entering into the technical details of the manipulation to consider briefly the advantages to be derived--which will be better appreciated after an actual trial. my experience (which is at present limited) is that they are far superior to glass for all purposes except portraiture of the human form or instantaneous pictures where extreme rapidity is necessary, but for all ordinary cases of rapid exposure they are sufficiently quick. the first advantage, which i soon discovered, is their entire freedom from halation. this, with glass plates, is inseparable, and even when much labor has been bestowed on backing them, the halation is painfully apparent. these films never frill, being made of emulsion which has been made insoluble. compare the respective weights of the two substances--one plate weighing more than a dozen films of the same size. again, on comparing a stripping film negative with one on glass of the same exposure and subject, it will be found there is a greater sharpness or clearness in the detail, owing, i am of opinion, to the paper absorbing the light immediately it has penetrated the emulsion, the result being a brilliant negative. landscapes on stripped films can be retouched or printed from on either side, and the advantage in this respect for carbon or mechanical printing is enormous. now, imagine the tourist working with glass, and compare him to another working with films. the one works in harness, tugging, probably, a half hundredweight of glass with him from place to place, paying extra carriage, extra tips, and in a continual state of anxiety as to possible breakage, difficulty of packing, and having to be continually on the lookout for a dark place to change the plates, and, perhaps, on his return finds numbers of his plates damaged owing to friction on the surface; while the disciple of _films_, lightly burdened with only camera and slide, and his (say two hundred) films in his pockets, for they lie so compact together. then the advantages to the tourists abroad, their name is "legion," not the least being the ease of guarding your exposed pictures from the custom house officials, who almost always seek to make matters disagreeable in this respect, and lastly, though not least, the ease with which the negatives can be stowed away in envelopes or albums, etc., when reference to them is easy in the extreme. now, having come (rightly, i think, you will admit) to the conclusion that films have these advantages, you naturally ask, what are their disadvantages? remembering, then, that i am only advocating stripping films, i consider they have but two disadvantages: first, they entail some additional outlay in the way of apparatus, etc. second, they are a little more trouble to finish than the glass negatives, which sink into insignificance when the manifold advantages are considered. in order to deal effectively with the second objection i mentioned, viz., the extra trouble and perseverance, i propose, with your permission, to carry a negative through the different stages from exposure to completion, and in so doing i shall endeavor to make the process clear to you, and hope to enlist your attention. the developer i use is slightly different to that of the eastman company, and is as follows: a. sulphite of soda. ounces. to be dissolved in ounces of hot distilled water, then rendered slightly acid with citric acid, then add-- pyrogallic acid. ounce. water to make up to ounces. b. pure carbonate of soda. ounce. water to make up in all to ounces. c. pure carbonate of potash. ounce. water to make up to ounces. d. bromide of potassium. ounce. water to make up to ounces. i have here two half-plate films exposed at : a.m. to-day, one with five and one with six seconds' exposure, subject chiefly middle distance. i take minims a, minims d, and minims b, and make up to ounces water. i do not soak the films in water. there is no need for it. in fact, it is prejudicial to do so. i place the films face uppermost in the dish, and pour on the developer on the center of the films. you will observe they lie perfectly flat, and are free from air bubbles. rock the dish continually during development, and when the high lights are out add from to minims c, and finish development and fix. the negatives being complete, i ask you to observe that both are of equal quality, proving the latitude of exposure permissible. i now coat a piece of glass half an inch larger all round than the negative with india rubber solution (see eastman formula), and squeegee the negative face downward upon the rubber, interposing a sheet of blotting paper and oilskin between the negative and squeegee to prevent injury to the exposed rubber surface, and then place the negative under pressure with blotting paper interposed until moderately dry only. i then pour hot water upon it, and, gently rocking the dish, you see the paper floats from the film without the necessity for pulling it with a pin, leaving the film negative on the glass. now, the instructions say remove the remaining soluble gelatine with camel's hair brush, but, unless it requires intensifying, which no properly developed negative should require, you need not do so, but simply pour on the gelatine solution (see eastman formula), well covering the edges of the film, and put on a level shelf to dry. i will now take up a negative in this state on the glass, but dry, and carefully cut round the edges of the film, and you see i can readily pull off the film with its gelatine support. having now passed through the whole of the process, it behooves us to consider for a few minutes the causes of failure in the hands of beginners and their remedies: . the rubber will not flow over glass? solution too thick, glass greasy. . rubber peels off on drying? dirty glass. . negative not dense enough? use more bromide and longer development. . gelatine cracks on being pulled off? add more glycerine. . gelatine not thick enough? gelatine varnish too thin, not strong enough. . does not dry sufficiently hard? too much glycerine.--_e.h. jaques, reported in br. jour. of photography._ * * * * * how different tones in gelatino-chloride prints may be varied by developers. the following formulæ are for use with gelatino-chloride paper or plates. the quantities are in each case calculated for one ounce, three parts of each of the following solutions being employed and added to one part of solution of protosulphate of iron. strength, grains to the ounce. _slaty blue._ .--one part of the above solution to three parts of a solution of citrate of ammonia. _greenish brown._ .--citric acid. grains carbonate of ammonia. " .--citrate of ammonia. grains. chloride of sodium. " .--citrate of ammonia. grains. chloride of sodium. " _sepia brown._ .--citrate of ammonia. grains. chloride of sodium. " _clear red brown._ .--citric acid. grains. carbonate of magnesia. " _warm gray brown._ .--citric acid. grains. carbonate of soda. " _deep red brown._ .--citric acid. grains. carbonate of potash. " _green blue._ .--citric acid. grains. carbonate of soda. " citrate of potash. " oxalate of potash. " _sepia red._ .--citric acid. grains. carbonate of soda. " citrate of potash. " oxalate of potash. " .--citric acid. grains. carbonate of magnesia. " carbonate of potash. " oxalate of potash. " _sepia yellow._ .--citric acid. grains. carbonate of magnesia. " citrate of ammonia. " .--citric acid. grains. carbonate of magnesia. " carbonate of ammonia. " chloride of sodium. " _blue black._ .--citric acid. grains. carbonate of ammonia. " carbonate of magnesia. " .--citric acid. grains. carbonate of magnesia. " carbonate of ammonia. " .--citric acid. grains. carbonate of magnesia. " citrate of potash. " oxlate of potash. " .--citric acid. grains. carbonate of magnesia. " citrate of potash. " oxalate of potash. " .--citric acid. grains. carbonate of magnesia. " citrate of potash. " oxalate of potash. " _a more intense blue black._ .--citric acid. grains. carbonate of magnesia. " citrate of potash. " oxalate of potash. " _a clearer blue._ .--citrate of potash. grains. oxalate of potash. " in the photographic exhibition at florence, the firm of corvan[ ] places on view a frame containing twenty proofs produced by the foregoing twenty formulæ, in such a way that the observer can compare the value of each tone and select that which pleases him best.--_le moniteur de la photographie, translated by british jour. of photo._ [footnote : does this mean mr. a. cowan?--_translator._] * * * * * note on the construction of a distillery chimney. at a recent meeting of the industrial society of amiens, mr. schmidt, engineer of the steam users' association, read a paper in which he described the process employed in the construction of a large chimney of peculiar character for the rocourt distillery, at st. quentin. [illustration: fig. --elevation.] this chimney, which is cylindrical in form, is feet in height, and has an internal diameter of ½ feet from base to summit. the coal consumed for the nine generators varies between and , pounds per hour and per square feet of section. the ground that was to support this chimney consisted of very aquiferous, cracked beds of marl, disintegrated by infiltrations of water from the distillery, and alternating with strata of clay. it became necessary, therefore, to build as light a chimney as possible. the problem was solved as follows, by mr. guendt, who was then superintendent of the rocourt establishment. upon a wide concrete foundation a pedestal was built, in which were united the various smoke conduits, and upon this pedestal were erected four lattice girders, c, connected with each other by st. andrew's crosses. the internal surface of these girders is vertical and the external is inclined. within the framework there was built a five-inch thick masonry wall of bricks, made especially for the purpose. the masonry was then strengthened and its contact with the girders assured by numerous hoops, especially at the lower part; some of them internal, others external, to the surface of the girders, and others of angle irons, all in four parts. [illustration: fig. --horizontal section.] the anchors rest upon a cast iron foundation plate connected, through strong bolts embedded in the pedestal, with a second plate resting upon the concrete. as the metallic framework was calculated for resisting the wind, the brick lining does not rest against it permanently above. the weight of the chimney is , , pounds, and the foundation is about square feet in area; and, consequently, the pressure upon the ground is about pounds to the square inch. the cost was $ , . [illustration: fig. --vertical section of the chimney.] the chimney was built six years ago, and has withstood the most violent hurricanes. the mounting of the iron framework was effected by means of a motor and two men, and took a month. the brick lining was built up in eight days by a mason and his assistant. a chimney of the same size, all of brick, erected on the same foundation, would have weighed , , pounds (say a load of , pounds to the square inch), and would have cost about $ , . the chimney of the rocourt distillery is, therefore, lighter by half, and cost about a third more, than one of brick; but, at the present price of metal, the difference would be slight.--_annales industrielles._ * * * * * the production of oxygen by brin's process. considerable interest has been aroused lately in scientific and industrial circles by a report that separation of the oxygen and nitrogen of the air was being effected on a large scale in london by a process which promises to render the gases available for general application in the arts. the cheap manufacture of the compounds of nitrogen from the gas itself is still a dream of chemical enthusiasts; and though the pure gas is now available, the methods of making its compounds have yet to be devised. but the industrial processes which already depend directly or indirectly on the chemical union of bodies with atmospheric oxygen are innumerable. in all these processes the action of the gas is impeded by the bulky presence of its fellow constituent of air, nitrogen. we may say, for instance, in homely phrase, that whenever a fire burns there are four volumes of nitrogen tending to extinguish it for every volume of oxygen supporting its combustion, and to the same degree the nitrogen interferes with all other processes of atmospheric oxidation, of which most metallurgical operations may be given as instances. if, then, it has become possible to remove this diluent gas simply and cheaply in order to give the oxygen free play in its various applications, we are doubtless on the eve of a revolution among some of the most extensive and familiar of the world's industries. a series of chemical reactions has long been known by means of which oxygen could be separated out of air in the laboratory, and at various times processes based on these reactions have been patented for the production of oxygen on a large scale. until recently, however, none of these methods gave sufficiently satisfactory results. the simplest and perhaps the best of them was based on the fact first noticed by boussingault, that when baryta (bao) is heated to low redness in a current of air, it takes up oxygen and becomes barium dioxide (bao_{ }), and that this dioxide at a higher temperature is reconverted into free oxygen and baryta, the latter being ready for use again. for many years it was assumed, however, by chemists that this ideally simple reaction was inapplicable on a commercial scale, owing to the gradual loss of power to absorb oxygen which was always found to take place in the baryta after a certain number of operations. about eight years ago messrs. a. & l. brin, who had studied chemistry under boussingault, undertook experiments with the view of determining why the baryta lost its power of absorbing oxygen. they found that it was owing to molecular and physical changes caused in it by impurities in the air used and by the high temperature employed for decomposing the dioxide. they discovered that by heating the dioxide in a partial vacuum the temperature necessary to drive off its oxygen was much reduced. they also found that by supplying the air to the baryta under a moderate pressure, its absorption of oxygen was greatly assisted. under these conditions, and by carefully purifying the air before use, they found that it became possible to use the baryta an indefinite number of times. thus the process became practically, as it was theoretically, continuous. after securing patent protection for their process, messrs. brin erected a small producer in paris, and successfully worked it for nearly three years without finding a renewal of the original charge of baryta once necessary. this producer was exhibited at the inventions exhibition in london, in . subsequently an english company was formed, and in the autumn of last year brin's oxygen company began operations in horseferry road, westminster, where a large and complete demonstration plant was erected, and the work commenced of developing the production and application of oxygen in the industrial world. [illustration: apparatus for making oxygen.] we give herewith details of the plant now working at westminster. it is exceedingly simple. on the left of the side elevation and plan are shown the retorts, on the right is an arrangement of pumps for alternately supplying air under pressure and exhausting the oxygen from the retorts. as is shown in the plan, two sets of apparatus are worked side by side at westminster, the seventy-two retorts shown in the drawings being divided into two systems of thirty-six. each system is fed by the two pumps on the corresponding side of the boiler. each set of retorts consists of six rows of six retorts each, one row above the other. they are heated by a small wilson's producer, so that the attendant can easily regulate the supply of heat and obtain complete control over the temperature of the retorts. the retorts, a, are made of wrought iron and are about ft long and in. diameter. experience, however, goes to prove that there is a limit to the diameter of the retorts beyond which the results become less satisfactory. this limit is probably somewhat under in. each retort is closely packed with baryta in lumps about the size of a walnut. the baryta is a heavy grayish porous substance prepared by carefully igniting the nitrate of barium; and of this each retort having the above dimensions holds about lb. the retorts so charged are closed at each end by a gun metal lid riveted on so as to be air tight. from the center of each lid a bent gun metal pipe, b, connects each retort with the next of its series, so that air introduced into the end retort of any row may pass through the whole series of six retorts. suppose now that the operations are to commence. the retorts are first heated to a temperature of about ° c. or faint redness, then the air pumps, c c, are started. air is drawn by them through the purifier, d, where it is freed from carbon dioxide and moisture by the layers of quicklime and caustic soda with which the purifier is charged. the air is then forced along the pipe, e, into the small air vessel, f, which acts as a sort of cushion to prevent the baryta in the retorts being disturbed by the pulsation of the pumps. from this vessel the air passes by the pipe, g, and is distributed in the retorts as rapidly as possible at such a pressure that the nitrogen which passes out unabsorbed at the outlet registers about lb. to the square inch. with the baryta so disposed in the retorts as to present as large a superficies as possible to the action of the air, it is found that in ½ to hours--during which time about , cub. ft of air have been passed through the retorts--the gas at the outlet fails to extinguish a glowing chip, indicating that oxygen is no longer being absorbed. the pumping now ceases, and the temperature of the retorts is raised to about ° c. the workman is able to judge the temperature with sufficient accuracy by means of the small inspection holes, h, fitted with panes of mica, through which the color of the heat in the furnace can be distinguished. the pumps are now reversed and the process of exhaustion begins. at westminster the pressure in the retorts is reduced to about ½ in. of mercury. in this partial vacuum the oxygen is given off rapidly, and if forced by the pumps through another pipe and away into an ordinary gas holder, where it is stored for use. with powerful pumps such as are used in the plant under notice the whole of the oxygen can be drawn off in an hour, and from one charge a yield of about , cub. ft. is obtained. with a less perfect vacuum the time is longer--even as much as four hours. the whole operation of charging and exhausting the retorts can be completed in from three to four hours. as soon as the evolution of oxygen is finished, the doors, k, and ventilators, l, may be opened and the retorts cooled for recharging. the cost of producing oxygen at westminster, under specially expensive conditions, is high--about s. per , cub. ft. when we consider, however, that the cost should only embrace attendance, fuel, wear and tear, and a little lime and soda for the purifiers, that the consumption of fuel is small, the wear and tear light, and that the raw material--air--is obtained for nothing, it ought to be possible to produce the gas for a third or fourth of this amount in most of our great manufacturing centers, where the price of fuel is but a third of that demanded in london, and where provision could be made for economizing the waste heat, which is entirely lost in the westminster installation. moreover, in estimating this cost all the charges are thrown on the oxygen; were there any means of utilizing the , cub. ft. of nitrogen at present blown away as waste for every thousand cubic feet of oxygen produced, the nitrogen would of course bear its share of the cost. the question of the application of the oxygen is one which must be determined in its manifold bearings mainly by the experiments of chemists and scientific men engaged in industrial work. having ascertained the method by which and the limit of cost within which it is possible to use oxygen in their work, it can be seen whether by brin's process the gas can be obtained within that limit. mr. s.r. ogden, the manager of the corporation gasworks at blackburn, has already made interesting experiments on the application of oxygen in the manufacture of illuminating gas. in order to purify coal gas from compounds of sulphur, it is passed through purifiers charged with layers of oxide of iron. when the oxide of iron has absorbed as much sulphur as it can combine with, it is described as "foul." it is then discharged and spread out in the open air, when, under the influence of the atmospheric oxygen, it is rapidly decomposed, the sulphur is separated out in the free state, and oxide of iron is reformed ready for use again in the purifiers. this process is called revivification, and it is repeated until the accumulation of sulphur in the oxide is so great ( to per cent.) that it can be profitably sold to the vitriol maker. hawkins discovered that by introducing about per cent. of air into the gas before passing it through the purifiers, the oxygen of the air introduced set free the sulphur from the iron as fast as it was absorbed. thus the process of revivification could be carried on in the purifiers themselves simultaneously with the absorption of the sulphur impurities in the gas. a great saving of labor was thus effected, and also an economy in the use of the iron oxide, which in this way could be left in the purifiers until charged with per cent. of sulphur. unfortunately it was found that this introduction of air for the sake of its oxygen meant also the introduction of much useless nitrogen, which materially reduced the illuminating power of the gas. to restore this illuminating power the gas had to be recarbureted, and this again meant cost in labor and material. now, mr. ogden has found by a series of conclusive experiments made during a period of seventy-eight days upon a quantity of about , , cub. ft. of gas, that by introducing per cent. of oxygen into the gas instead of per cent. of air, not only is the revivification _in situ_ effected more satisfactorily than with air, but at the same time the illuminating power of the gas, so far from being decreased, is actually increased by one candle unit. [illustration: the production of oxygen by brin's process.] so satisfied is he with his results that he has recommended the corporation to erect a plant for the production of oxygen at the blackburn gas works, by which he estimates that the saving to the town on the year's make of gas will be something like £ , . the practical observations of mr. ogden are being followed up by a series of exhaustive experiments by mr. valon, a.m. inst. c.e., also a gas engineer. the make of an entire works at westgate is being treated by him with oxygen. mr. valon has not yet published his report, as the experiments are not quite complete; but we understand that his results are even more satisfactory than those obtained at blackburn. in conclusion we may indicate a few other of the numerous possible applications of cheap oxygen which might be realized in the near future. the greatest illuminating effect from a given bulk of gas is obtained by mixing it with the requisite proportion of oxygen, and holding in the flame of the burning mixture a piece of some solid infusible and non-volatile substance, such as lime. this becomes heated to whiteness, and emits an intense light know as the drummond light, used already for special purposes of illumination. by supplying oxygen in pipes laid by the side of the ordinary gas mains, it would be possible to fix small drummond lights in place of the gas burners now used in houses; this would greatly reduce the consumption of gas and increase the light obtained, or even render possible the employment of cheap non-illuminating combustible gases other than coal gas for the purpose. two obstacles at present lie in the way of this consummation--the cost of the oxygen and the want of a convenient and completely refractory material to take the place of the lime. messrs. brin believe they have overcome the first obstacle, and are addressing themselves, we believe, to the removal of the second. again, the intense heat which the combustion of carbon in cheap oxygen will place at the disposal of the metallurgist cannot fail to play an important part in his operations. there are many processes, too, of metal refining which ought to be facilitated by the use of the gas. then the production of pure metallic oxides for the manufacture of paints, the bleaching of oils and fats, the reduction of refractory ores of the precious metals on a large scale, the conversion of iron into steel, and numberless other processes familiar to the specialists whose walk is in the byways of applied chemistry, should all profit by the employment of this energetic agent. doubtless, too, the investigation into methods of producing the compounds of nitrogen so indispensable as plant foods, and for which we are now dependent on the supplies of the mineral world, may be stimulated by the fact that there is available by brin's process a cheap and inexhaustible supply of pure nitrogen.--_industries._ * * * * * french disinfecting apparatus. [illustration: improved disinfecting apparatus.] we represent herewith a sanitary train that was very successfully used during the prevalence of an epidemic of _sudor anglicus_ in poitou this year. it consisted of a movable stove and a boiler. in reality, to save time, such agricultural locomotives as could be found were utilized; but hereafter, apparatus like those shown in the engraving, and which are specially constructed to accompany the stoves, will be employed. we shall quote from a communication made by prof. brouardel to the academy of medicine on this subject, at its session of september : in the country we can never think of disinfecting houses with sulphurous acid, as the peasants often have but a single room, in which the beds of the entire family are congregated. every one knows that the agglomerations that compose the same department are often distant from each other and the chief town by from two to three miles or more. this is usually the case in the departments of vienne, haute vienne, indre, etc. to find a disinfecting place in the chief town of the department is still difficult, and to find one in each of the hamlets is absolutely impossible. families in which there are invalids are obliged to carry clothing and bedding to the chief town to be disinfected, and to go after them after the expiration of twenty-four hours. this is not an easy thing to do. it is easy to understand what difficulties must be met with in many cases, and so one has to be content to prescribe merely washing, and bleaching with lime--something that is simple and everywhere accepted, but insufficient. so, then, disinfection with sulphurous acid, which is easy in large cities, as was taught by the cholera epidemics of last year, is often difficult in the country. the objection has always be made to it, too, that it is of doubtful efficacy. it is not for us to examine this question here, but there is no doubt that damp steam alone, under pressure, effects a perfect disinfection, and that if this mode of disinfection could be applied in the rural districts (as it can be easily done in cities), the public health would be better protected in case of an epidemic. in cities one or more stationary steam stoves can always be arranged; but in the country movable ones are necessary. from instructions given by prof. brouardel, messrs. geneste & herscher have solved the problem of constructing such stoves in a few days, and four have been put at the disposal of the mission. dr. thoinot, who directed this mission, in order to make an experiment with these apparatus, selected two points in which cases of _sudor_ were still numerous, and in which the conditions were entirely different, and permitted of studying the working of the service and apparatus under various phases. one of these points was dorat, chief town of haute vienne, a locality with a crowded population and presenting every desirable resource; and the other was the commune of mauvieres, in indre, where the population was scattered through several hamlets. the first stove was operated at dorat, on the th of june, and the second at mauvieres, on the st of july. a gendarme accompanied the stove in all its movements and remained with it during the disinfecting experiments. the dorat stove was operated on the th of june and the st, d, and d of july. on the th of june it proceeded to disinfect the commune of darnac. the mauvieres stove, in the first place, disinfected the chief town of this commune on the st of july, and on the next day it was taken to poulets, a small hamlet, and a dependent of the commune of mauvieres. all the linen and all the clothing of the sick of this locality, which had been the seat of _sudor_, especially infantile, was disinfected. on the th of july, the stove went to concremiers, a commune about three miles distant, and there finished up the disinfection that until then had been performed in the ordinary way. the epidemic was almost everywhere on the wane at this epoch; but we judge that the test of the stoves was sufficient. we are able to advance the following statement boldly: for the application of disinfection in the rural districts, the movable stove is the most practical thing that we know of. it is easily used, can be taken to the smallest hamlets, and can be transported over the roughest roads. it inspires peasants with no distrust. the first repugnance is easily overcome, and every one, upon seeing that objects come from the stove unharmed, soon hastens to bring to it all the contaminated linen, etc., that he has in the house. further, we may add that the disinfection is accomplished in a quarter of an hour, and that it therefore keeps the peasant but a very short time from his work--an advantage that is greatly appreciated. finally, a day well employed suffices to disinfect a small settlement completely. upon the whole, disinfection by the stove under consideration is the only method that can always and everywhere be carried out. we believe that it is called upon to render the greatest services in the future. the movable stove, regarding which prof. brouardel expresses himself in the above terms, consists of a cylindrical chamber, ½ feet in internal diameter and feet in length, closed in front by a hermetically jointed door. this cylinder, which constitutes the disinfection chamber, is mounted upon wheels and is provided with shafts, so that it can easily be hauled by a horse or mule. the cylinder is of riveted iron plate, and is covered with a wooden jacket. the door is provided with a flange that enters a rubber lined groove in the cylinder, and to it are riveted wrought iron forks that receive the nuts of hinged bolts fixed upon the cylinder. the nuts are screwed up tight, and the flange of the door, compressing the rubber lining, renders the joint hermetical. the door, which is hinged, is provided with a handle, which, when the stove is closed, slides over an inclined plane fixed to the cylinder. the steam enters a cast iron box in the stove through a rubber tube provided with a threaded coupling. the entrance of the steam is regulated by a cock. the box is provided with a safety and pressure gauge and a small pinge cock. in the interior of the stove the entrance of the steam is masked by a large tinned copper screen, which is situated at the upper part and preserves the objects under treatment from drops of water of condensation. these latter fall here and there from the screen, follow the sides of the cylinder, and collect at the bottom, from whence they are drawn off through a cock placed in the rear. the sides are lined internally with wood, which prevents the objects to be infected from coming into contact with the metal. the objects to be treated are placed upon wire cloth shelves. the pinge cock likewise serves for drawing off the air or steam contained in the apparatus. the stove is supported upon an axle through the intermedium of two angle irons riveted longitudinally upon the cylinder. the axle is cranked, and its wheels, which are of wood, are ½ feet in diameter. the shafts are fixed to the angle irons. the apparatus is, in addition, provided with a seat, a brake, and prop rods before and behind to keep it horizontal when in operation. the boiler that supplies this stove is vertical and is mounted upon four wheels. it is jacketed with wood, and is provided with a water level, two gauge cocks, a pressure gauge, two spring safety valves, a steam cock provided with a rubber tube that connects with that of the stove, an ash pan, and a smoke stack. in the rear there are two cylindrical water reservoirs that communicate with each other, and are designed to feed the boiler through an injector. beneath these reservoirs there is a fuel box. in front there is a seat whose box serves to hold tools and various other objects.--_la nature._ * * * * * an electrical governor. we abstract the following from a paper on electric lighting by prof. j.a. fleeming, read before the iron and steel institute, manchester. the illustration is from _engineering_. [illustration: electrical governor.] one of the questions which most frequently occurs in reference to mill and factory lighting is whether the factory engines can be used to run the dynamo. as a broad, general rule, there can be no question that the best results are obtained by using a separate dynamo engine, controlled by a good governor, set apart for that purpose. with an ordinary shunt dynamo, the speed ought not to vary more than or per cent. of its normal value on either side of that value. hence, if a dynamo has a normal speed of , , it should certainly not vary over a greater range than from to to , to , . in many cases there may be shafting from which the necessary power can be taken, and of which the speed is variable only within these limits. there are several devices by which it has been found possible to enable a dynamo to maintain a constant electromotive force, even if the speed of rotation varies over considerable limits. one of these is that (see illustration) due to messrs. trotter & ravenshaw, and applicable to shunt or series machines. in the circuit of the field magnet is placed a variable resistance. this resistance is thrown in or out by means of a motor device actuated by an electromotive force indicator. a plunger of soft iron is suspended from a spring, and hangs within a solenoid of wire, which solenoid is in connection with the terminals of the dynamo. any increase or diminution of the electromotive force causes this iron to move in or out of the core, and its movement is made to connect or disconnect the gearing which throws in the field magnet resistance with a shaft driven by the engine itself. the principle of the apparatus is therefore that small variations of electromotive force are made to vary inversely the strength of the magnetic field through the intervention of a relay mechanism in which the power required to effect the movement is tapped from the engine. with the aid of such a governor it is possible to drive a dynamo from a mill shaft providing the requisite power, but of which the speed of rotation is not sufficiently uniform to secure alone efficient regulation of electromotive force. another device, patented by mr. crompton, is a modification of that method of field magnet winding commonly known as compound winding. the field magnets are wound over with two wires, one of which has a high resistance and is arranged as a shunt, and the other of which has a low resistance and is arranged in series. instead, however, of the magnetizing powers of these coils being united in the same direction as an ordinary compound winding, they are opposed to one another. that is to say, the current in the shunt wire tends to magnetize the iron of the field magnets in an opposite direction to that of the series wire. it results from this that any slight increase of speed diminishes the strength of the magnetic field, and _vice versa_. accordingly, within certain limits, the electromotive force of the dynamo is independent of the speed of rotation. * * * * * the electric current as a means of increasing the tractive adhesion of railway motors and other rolling contacts.[ ] [footnote : read before the american association for the advancement of science. new york meeting, .] by elias e. ries. the object of this paper is to lay before you the results of some recent experiments in a comparatively new field of operation, but one that, judging from the results already attained, is destined to become of great importance and value in its practical application to various branches of industry. i say "comparatively new" because the underlying principles involved in the experiments referred to have, to a certain extent, been employed (in, however, a somewhat restricted sense) for purposes analogous to those that form the basis of this communication. as indicated by the title, the subject that will now occupy our attention is the use of the electric current as a means of increasing and varying the frictional adhesion of rolling contacts and other rubbing surfaces, and it is proposed to show how this effect may be produced, both by means of the direct action of the current itself and by its indirect action through the agency of electro-magnetism. probably the first instance in which the electric current was directly employed to vary the amount of friction between two rubbing surfaces was exemplified in edison's electro-motograph, in which the variations in the strength of a telephonic current caused corresponding variations in friction between a revolving cylinder of moistened chalk and the free end of an adjustable contact arm whose opposite extremity was attached to the diaphragm of the receiving telephone. this device was extremely sensitive to the least changes in current strength, and if it were not for the complication introduced by the revolving cylinder, it is very likely that it would to-day be more generally used. it has also been discovered more recently that in the operation of electric railways in which the track rails form part of the circuit, a considerable increase in the tractive adhesion of the driving wheels is manifested, due to the passage of the return current from the wheels into the track. in the baltimore and hampden electric railway, using the daft "third rail" system, this increased tractive adhesion enables the motors to ascend without slipping a long grade of feet to the mile, drawing two heavily loaded cars, which result, it is claimed, is not attainable by steam or other self-propelling motors of similar weight. in the two instances just cited the conditions are widely different, as regards the nature of the current employed, the mechanical properties of the surfaces in contact, and the electrical resistance and the working conditions of the respective circuits. in both, however, as clearly demonstrated by the experiments hereinafter referred to, the cause of the increased friction is substantially the same. in order to ascertain the practical value of the electric current as a means of increasing mechanical friction, and, if possible, render it commercially and practically useful wherever such additional friction might be desirable, as for example in the transmission of power, etc., a series of experiments were entered into by the author, which, though not yet fully completed, are sufficiently advanced to show that an electric current, when properly applied, is capable of very materially increasing the mechanical friction of rotating bodies, in some cases as much as from to per cent., with a very economical expenditure of current; this increase depending upon the nature of the substances in contact and being capable of being raised by an increased flow of current. before entering into a description of the means by which this result is produced, and how it is proposed to apply this method practically to railway and other purposes, it may be well to give a general outline of what has so far been determined. these experiments have shown that the coefficient of friction between two conducting surfaces is very much increased by the passage therethrough of an electric current of _low electromotive force and large volume_, and this is especially noticeable between two rolling surfaces in peripheral contact with each other, or between a rolling and a stationary surface, as in the case of a driving wheel running upon a railway rail. this effect increases with the number of amperes of current flowing through the circuit, of which the two surfaces form part, and is not materially affected by the electromotive force, so long as the latter is sufficient to overcome the electrical resistance of the circuit. this increase in frictional adhesion is principally noticeable in iron, steel, and other metallic bodies, and is due to a molecular change in the conducting substances at their point of contact (which is also the point of greatest resistance in the circuit), caused by the heat developed at that point. this heat is ordinarily imperceptible, and becomes apparent only when the current strength is largely augmented. it is therefore probable that a portion of this increased tractive adhesion is due directly to the current itself aside from its heating effect, although i have not as yet been able to ascertain this definitely. the most economical and efficient results have been obtained by the employment of a transformed current of extremely low electromotive force (between ½ and volt), but of very large volume or quantity, this latter being variable at will, so as to obtain different degrees of frictional resistance in the substances under observation. these experiments were originally directed mainly toward an endeavor to increase the tractive adhesion of the driving wheels of locomotives and other vehicles, and to utilize the electric current for this purpose in such a manner as to render it entirely safe, practical, and economical. it will be apparent at once that a method of increasing the tractive power of the present steam locomotives by more than per cent. without adding to their weight and without injury to the roadbed and wheel tires, such as is caused by the sand now commonly used, would prove of considerable value, and the same holds true with respect to electrically propelled street cars, especially as it has been found exceedingly difficult to secure sufficient tractive adhesion on street railways during the winter season, as well as at other times, on roads having grades of more than ordinary steepness. as this, therefore, is probably the most important use for this application of the electric current, it has been selected for illustrating this paper. i have here a model car and track arranged to show the equipment and operation of the system as applied to railway motors. the current in the present instance is one of alternating polarity which is converted by this transformer into one having the required volume. the electromotive force of this secondary current is somewhat higher than is necessary. in practice it would be about half a volt. you will notice upon a closer inspection that one of the forward driving wheels is insulated from its axle, and the transformed current, after passing to a regulating switch under the control of the engineer or driver, goes to this insulated wheel, from which it enters the track rail, then through the rear pair of driving wheels and axles to the opposite rail, and then flows up through the forward uninsulated wheel, from the axle of which it returns by way of a contact brush to the opposite terminal of the secondary coil of the transformer. thus the current is made to flow _seriatim_ through all four of the driving wheels, completing its circuit through that portion of the rails lying between the two axles, and generating a sufficient amount of heat at each point of contact to produce the molecular change before referred to. by means of the regulating switch the engineer can control the amount of current flowing at any time, and can even increase its strength to such an extent, in wet or slippery weather, as to _evaporate any moisture_ that may adhere to the surface of the rails at the point of contact with the wheels while the locomotive or motor car is under full speed. it will be apparent that inasmuch as the "traction circuit" moves along with the locomotive, and is complete through its driving wheel base, the track rails in front and rear of the same are at all times entirely free from current, _and no danger whatever can occur by coming in contact with the rails between successive motors_. moreover, the potential used in the present arrangement, while sufficient to overcome the extremely low resistance of the moving circuit, is too small to cause an appreciable loss of current from that portion of the rails in circuit, even under the most unfavorable conditions of the weather. in practice the primary current necessary is preferably generated by a small high speed alternating dynamo on the locomotive, the current being converted by means of an inductional transformer. to avoid the necessity for electrically bridging the rail joints, a modified arrangement may be employed, in which the electrical connection is made directly with a fixed collar on the forward and rear driving axles, the current dividing itself in parallel between the two rails in such a manner that, if a defective joint exists in the rail at one side, the circuit is still complete through the rail on the other; and as the rails usually break joints on opposite sides, this arrangement is found very effective. the insulation of the driving wheels is very easily effected in either case. as the amount of additional tractive adhesion produced depends upon the _quantity_ of current flowing rather than upon its pressure, the reason for transforming the current as described will be apparent, and its advantages over a direct current of higher tension and less quantity, both from an economical and practical standpoint, will for this reason be clear. the amount of heat produced at the point of contact between the wheels and rails is never large enough to injure or otherwise affect them, although it may be quite possible to increase the current sufficiently to produce a very considerable heating effect. the amount of current sent through the traction circuit will of course vary with the requirements, and as the extent to which the resistance to slipping may be increased is very great, this method is likely to prove of considerable value. while in some cases the use of such a method of increasing the tractive power of locomotives would be confined to ascending gradients and the movement of exceptionally heavy loads, in others it would prove useful as a _constant_ factor in the work of transportation. in cases like that of the new york elevated railway system, where the traffic during certain hours is much beyond the capacity of the trains, and the structure unable to support the weight of heavier engines, a system like that just described would prove of very great benefit, as it would easily enable the present engines to draw two or three additional cars with far less slipping and lost motion than is the case with mechanical friction alone, at a cost for tractive current that is insignificant compared to the advantages gained. other cases may be cited in which this method of increasing friction will probably be found useful, aside from its application to railway purposes, but these will naturally suggest themselves and need not be further dwelt upon. in the course of the experiments above described, another and somewhat different method of increasing the traction of railway motors has been devised, which is more particularly adapted to electric motors for street railways, and is intended to be used in connection with a system of electric street railways now being developed by the author. in this system _electro-magnetism_ provides the means whereby the increase in tractive adhesion is produced, and this result is attained in an entirely novel manner. several attempts have heretofore been made to utilize magnetism for this purpose, but apparently without success, chiefly because of the crude and imperfect manner in which most of these attempts have been carried out. the present system owes its efficiency to the formation of _a complete and constantly closed magnetic circuit_, moving with the vehicle and completed through the two driving axles, wheels, and that portion of the track rails lying between the two pairs of wheels, in a manner similar to that employed in the electrical method before shown. we have here a model of a second motor car equipped with the apparatus, mounted on a section of track and provided with means for measuring the amount of tractive force exerted both with and without the passage of the current. you will notice that each axle of the motor car is wound with a helix of insulated wire, the helices in the present instance being divided to permit the attachment to the axles of the motor connections. the helices on both axles are so connected that, when energized, they induce magnetic lines of force that flow in the same direction through the magnetic circuit. there are, therefore, four points at which the circuit is maintained closed by the rolling wheels, and as the resistance to the flow of the lines of force is greatest at these points, the magnetic saturation there is more intense, and produces the most effective result just where it is most required. now, when the battery circuit is closed through the helices, it will be observed that the torque, or pull, exerted by the motor car is fully twice that exerted by the motor with the traction circuit open, and, by increasing the battery current until the saturation point of the iron is reached, the tractive force is _increased nearly per cent._, as shown by the dynamometer. a large portion of this resistance to the slipping or skidding of the driving wheels is undoubtedly due to direct magnetic attraction between the wheels and track, this attraction depending upon the degree of magnetic saturation and the relative mass of metal involved. but by far the greatest proportion of the increased friction is purely the result of the change in position of the iron molecules due to the well known action of magnetism, which causes a direct and close _interlocking action_, so to speak, between the molecules of the two surfaces in contact. this may be illustrated by drawing a very thin knife blade over the poles of an ordinary electro-magnet, first with the current on and then off. in the model before you, the helices are fixed firmly to, and revolve with, the axles, the connections being maintained by brushes bearing upon contact rings at each end of the helices. if desired, however, the axles may revolve loosely within the helices, and instead of the latter being connected for cumulative effects, they may be arranged in other ways so as to produce either subsequent or opposing magnetic forces, leaving certain portions of the circuit neutral and concentrating the lines of force wherever they maybe most desirable. such a disposition will prove of advantage in some cases. the amount of current required to obtain this increased adhesion in practice is extremely small, and may be entirely neglected when compared to the great benefits derived. the system is very simple and inexpensive, and the amount of traction secured is entirely within the control of the motor man, as in the electric system. it will be seen that the car here will not, with the traction circuit open, propel itself up hill when one end of the track is raised more than inches above the table; but with the circuit energized it will readily ascend the track as you now see it, with one end about ½, inches above the other in a length of three feet, _or the equivalent of a per cent. grade_; and this could be increased still further if the motor had power enough to propel itself against the force of gravity on a steeper incline. as you will notice, the motor adheres very firmly to the track and requires a considerable push to force it down this per cent. grade, whereas with the traction circuit open it slips down in very short order, notwithstanding the efforts of the driving mechanism to propel it up. the resistance of the helices on this model is less than two ohms, and this will scarcely be exceeded when applied to a full sized car, the current from two or three cells of secondary batteries being probably sufficient to energize them. the revolution of the driving axles and wheels is not interfered with in the slightest, because in the former the axle boxes are outside the path of the lines of force, and in the case of the latter because each wheel practically forms a single pole piece, and in revolving presents continuously a new point of contact, of the same polarity, to the rail; the flow of the lines of force being most intense through the lower half of the wheels, and on a perpendicular line connecting the center of the axle with the rail. in winter all that is necessary is to provide each motor car with a suitable brush for cleaning the track rails sufficiently to enable the wheels to make good contact therewith, and any tendency to slipping or skidding may be effectually checked. by this means it is easily possible to increase the tractive adhesion of an ordinary railway motor from to per cent., without any increase in the load or weight upon the track; for it must be remembered that even that portion of the increased friction due to direct attraction does not increase the weight upon the roadbed, as this attraction is mutual between the wheels and track rails; and if this car and track were placed upon a scale and the circuit closed, it would not weigh a single ounce more than with the circuit open. it is obvious that this increase in friction between two moving surfaces can also be applied to _check_, as well as augment, the tractive power of a car or train of cars, and i have shown in connection with this model a system of braking that is intended to be used in conjunction with the electro-magnetic traction system just described. you will have noticed that in the experiments with the traction circuit the brake shoes here have remained idle; that is to say, they have not been attracted to the magnetized wheels. this is because a portion of the traction current has been circulating around this coil on the iron brake beam, inducing in the brake shoes magnetism of like polarity to that in the wheels to which they apply. they have therefore been _repelled_ from the wheel tires instead of being attracted to them. suppose now that it is desired to stop the motor car; instead of opening the traction circuit, the current flowing through the helices is simply reversed by means of this pole changing switch, whereupon the axles are magnetized in the opposite direction and the brake shoes are instantly drawn to the wheels with a very great pressure, as the current in the helices and brake coil now assist each other in setting up a very strong magnetic flow, sufficient to bring the motor car almost to an instant stop, if desired. the same tractive force that has previously been applied to increase the tractive adhesion now exercises its influence upon the brake shoes and wheels, with the result of not only causing a very powerful pressure between the two surfaces due to the magnetic attraction, but offering an extremely large frictional resistance in virtue of the molecular interlocking action before referred to. as shown in the present instance, a portion of the current still flows through the traction circuit and prevents the skidding of the wheels. the method thus described is equally applicable to increase the coefficient of friction in apparatus for the transmission of power, its chief advantage for this purpose being the ease and facility with which the amount of friction between the wheels can be varied to suit different requirements, or increased and diminished (either automatically or manually) according to the nature of the work being done. with soft iron contact surfaces the variation in friction is very rapid and sensitive to slight changes in current strength, and this fact may prove of value in connection with its application to regulating and measuring apparatus. in all cases the point to be observed is to maintain a closed magnetic circuit of low resistance through the two or more surfaces the friction of which it is desired to increase, and the same rule holds good with respect to the electric system, except that in the latter case the best effects are obtained when the area of surface in contact is smallest. for large contact areas the magnetic system is found to be most economical, and this system might possibly be used to advantage to prevent slipping of short wire ropes and belts upon their driving pulleys, in cases where longer belts are inapplicable as in the driving of dynamos and other machinery. experiments have also been, and are still being, made with the object of increasing friction by means of permanent magnetism, and also with a view to _diminishing_ the friction of revolving and other moving surfaces, the results of which will probably form the subject matter of a subsequent paper. enough has been said to indicate that the development of these two methods of increasing mechanical friction opens up a new and extensive field of operation, and enables electricity to score another important point in the present age of progress. the great range and flexibility of this method peculiarly adapt it to the purposes we have considered and to numerous others that will doubtless suggest themselves to you. its application to the increase of the tractive adhesion of railway motors is probably its most prominent and valuable feature at present, and is calculated to act as an important stimulus to the practical introduction of electric railways on our city streets, inasmuch as the claims heretofore made for cable traction in this respect are now no longer exclusively its own. on trunk line railways the use of sand and other objectionable traction-increasing appliances will be entirely dispensed with, and locomotives will be enabled to run at greater speed with less slipping of the wheels and less danger of derailment. their tractive power can be nearly doubled without any increase in weight, enabling them to draw heavier trains and surmount steeper grades without imposing additional weight or strain upon bridges and other parts of the roadbed. inertia of heavy trains can be more readily overcome, loss of time due to slippery tracks obviated, and the momentum of the train at full speed almost instantly checked by _one and the same means_. * * * * * electric launch. trials have been made at havre with an electric launch built to the order of the french government by the forges et chantiers de la mediterranée. the vessel, which has rather full lines, measures ft. between perpendiculars and ft. beam, and is tons register. the electromotor is the invention of captain krebs, who is already well known on account of his experiments in connection with navigable balloons, and of m. de zédé, naval architect. the propeller shaft is not directly coupled with the spindle of the motor, but is geared to it by spur wheels in the ratio of to , in order to allow of the employment of a light high-speed motor. the latter makes revolutions per minute, and develops horse power when driving the screw at revolutions. current is supplied by a new type of accumulators made by messrs. commelin & desmazures. one hundred and thirty two of these accumulators are fitted in the bottom of the boat, the total weight being about tons. in ordering this boat the french government stipulated a speed of knots to be maintained during three hours with an expenditure of horse power. the result of the trials gave a speed of ½ knots during five hours with horse power, and sufficient charge was left in the accumulators to allow the boat to travel on the following day for four hours. this performance is exceedingly good, since it shows that one horse power hour has been obtained with less than lb. of total weight of battery. * * * * * the commercial exchange, paris. leveling the ground, pulling down old buildings, and distributing light and air through her wide streets, paris is slowly and continuously pursuing her transformation. at this moment it is an entire district, and not one of the least curious ones, that is disappearing, leaving no other trace of its existence than the circular walls that once inclosed the wheat market. it is this building that, metamorphosed, is to become the commercial exchange that has been so earnestly demanded since by the commerce of paris. the question, which was simple in the first place, and consisted in the conversion of the wheat market into a commercial exchange, became complicated by a project of enlarging the markets. it therefore became necessary to take possession, on the one hand, of sixty seven estates, of a total area of , square feet, to clear the exchange, and, on the other, of , square feet to clear the central markets. in other words, out of $ , , voted by the common council for this work, $ , , are devoted to the dispossessions necessitated by the new exchange, $ , , to those necessitated by the markets, and $ , are appropriated to the wheat market. the work of demolition began last spring, and the odd number side of orleans street, deux-ecus street, from this latter to j.j. rousseau street, babille street, mercier street, and sortine street, now no longer exist. all this part is to-day but a desert, in whose center stands the iron trussing of the wheat market cupola. it is on these grounds that will be laid out the prolongation of louvre street in a straight line to coquilliere street. our engraving shows the present state of the work. what is seen of the wheat market will be preserved and utilized by mr. blondeau, the architect, who has obtained a grant from the commercial exchange to construct two edifices on two plots of an area of , square feet, fronting on louvre street, and which will bring the city an annual rent of $ , . [illustration: the new commercial exchange, paris.] around the rotunda that still exists there was a circular wall ½ feet in thickness. mr. blondeau has torn this down, and is now building another one appropriate to the new destination of the acquired estates. as for the trussing of the cupola, that is considered as a work of art, and care has been taken not to touch it. it was constructed at the beginning of this century, at an epoch when nothing but rudimentary tools were to be had for working iron, and it was, so to speak, forged. all the pieces were made with the hammer and were added one to the other in succession. this cupola will be glazed at the upper part, while the lower part will be covered with zinc. in the interior this part will be decorated with allegorical paintings representing the five divisions of the globe, with their commercial and industrial attributes. it was feared at one time that the hall, to which admission will be free, would not afford sufficient space, and the halls of the bordeaux and havre exchanges were cited. it is true that the hall of the wheat market has an area of but , square feet, but on utilizing the , feet of the circular gallery, which will not be occupied, it will reach , feet. as for the tower which stands at one side of the edifice, that was built by marie de medici for the astrologer whom she brought with her to paris from florence. on account of its historic interest, this structure will be preserved. on either side of this tower, overlooking the roofs of the neighboring dwellings, are perceived the summit of a tower of st. eustache church and a campanile of a pavilion of the markets.--_l'illustration._ * * * * * the manufacture of cocaine. cocaine is manufactured from the dry leaves of the _erythroxylon coca_, which grows in the valleys of the east cordilleras of south america--i.e., in the interior of peru and bolivia. the fresh leaves contain . to . per cent of cocaine, which percentage decreases considerably if the leaves are stored any length of time before being worked up. on the other hand, the alkaloid can be transported and kept without decomposition. this circumstance caused the author to devise a simple process for the manufacture of crude cocaine on the spot, neither peru nor bolivia being suitable countries for complicated chemical operations. after many experiments, he hit upon the following plan: the disintegrated coca leaves are digested at ° c. in closed vessels for two hours, with a very weak solution of sodium hydrate and petroleum (boiling between ° and ° c). the mass is filtered, pressed while still tepid, and the filtrate allowed to stand until the oil has completely separated from the aqueous solution. the oil is drawn off and carefully neutralized with very weak hydrochloric acid. a white bulky precipitate of cocaine hydrochloride is obtained, together with an aqueous solution of the same compound, while the petroleum is free from the alkaloid and may be used for the extraction of a fresh batch of leaves. the precipitate is dried, and by concentrating the aqueous solution a further quantity of the hydrochloride is obtained. both can be shipped without risk of decomposition. the product is not quite pure, but contains some hygrine, traces of gum and other matters. its percentage of alkaloid is per cent., while chemically pure cocaine hydrochloride (c_{ }h_{ }no_{ }. hcl) contains . per cent. of the alkaloid. the sodium hydrate solution cannot be replaced by milk of lime, nor can any other acid be used for neutralization. alcohol or ether are not suitable for extraction. a repetition of the process with once-extracted coca leaves gave no further quantity of cocaine, proving that all the cocaine goes into solution by one treatment. the same process serves on the small scale for the valuation of coca leaves. grms. of coca leaves are digested in a flask with c.c. of water, c.c. of / naoh ( grms. of naoh in c.c.) and c.c. of petroleum. the flask is loosely covered and warmed on the water bath for two hours, shaking it from to time. the mass is then filtered, the residue pressed, and the filtrate allowed to separate in two layers. the oil layer is run into a bottle and titrated back with / hcl ( grm. of hcl in c.c.) until exactly neutral. the number of c.c. of hydrochloric acid required for titrating back multiplied by . gives the percentage of cocaine in the sample. the following are some of the results with different samples of coca leaves of various age: contained per cent. of cocaine. coca leaves from mapiri, month old . % \ " " " yungas " " . % | " " " mapiri and yungas | months old . % | of the " " " cuzco (peru) |_ weight of months old . % | the dry " " " mapiri and yungas | leaves. year old . % | " " " cuzco " " " . % | " " " mapiri and yungas | years old . %/ coca leaves from yungas and cuzco, three years old, contained no trace of the alkaloid, whereas fresh green leaves from yungas contained . per cent. of the weight of the dry leaves. the same process is also applicable for the manufacture of quinine from poor quinine bark, with the single alteration that weak sulphuric acid must be used for the neutralization of the alkaline petroleum extract.--_h.t. pfeiffer, chem. zeit. ._ * * * * * [continued from supplement, no. , page .] the chemical basis of plant forms.[ ] by helen c. de s. abbott. the succession of plants from the lower to the higher forms will be reviewed superficially, and chemical compounds noted where they appear. when the germinating spores of the fungi, _myxomycetes_, rupture their walls and become masses of naked protoplasm, they are known as plasmodia. the plasmodium _Æthalium septicum_ occurs in moist places, on heaps of tan or decaying barks. it is a soft, gelatinous mass of yellowish color, sometimes measuring several inches in length. the plasmodium[ ] has been chemically analyzed, though not in a state of absolute purity. the table of reinke and rodewold gives an idea of its proximate constitution. many of the constituents given are always present in the living cells of higher plants. it cannot be too emphatically stated that where "biotic" force is manifested, these colloidal or albuminous compounds are found. the simplest form of plant life is an undifferentiated individual, all of its functions being performed indifferently by all parts of its protoplasm. the chemical basis of plasmodium is almost entirely composed of complex albuminous substances, and correlated with this structureless body are other compounds derived from them. aside from the chemical substances which are always present in living matter, and are essential properties of protoplasm, we find no other compounds. in the higher organisms, where these functions are not performed indifferently, specialization of tissues is accompanied by many other kinds of bodies. the algæ are a stage higher in the evolutionary scale than the undifferentiated noncellular plasmodium. the simple _alga protococcus_[ ] may be regarded as a simple cell. all higher plants are masses of cells, varying in form, function, and chemical composition. a typical living cell may be described as composed of a cell wall and contents. the cell wall is a firm, elastic membrane closed on all sides, and consists mainly of cellulose, water, and inorganic constituents. the contents consist of a semi-fluid colloidal substance, lying in contact with the inner surface of the membrane, and, like it, closed on all sides. this always is composed of albuminous substances. in the higher plants, at least, a nucleus occurs embedded in it; a watery liquid holding salts and saccharine substances in solution fills the space called the vacuole, inclosed by the protoplasm. these simple plants may be seen as actively moving cells or as non-motile cells. the former consist of a minute mass of protoplasm, granular and mostly colored green, but clear and colorless at the more pointed end, and where it is prolonged into two delicate filaments called cilia. after moving actively for a time they come to rest, acquire a spherical form, and invest themselves with a firm membrane of cellulose. this firm, outer membrane of the _protococcus_ accompanies a higher differentiation of tissue and localization of function than is found in the plasmodium. _hæatococcus_ and plasmodium come under the classes algæ and fungi of the thallothyta group. the division[ ] of this group into two classes is based upon the presence of chlorophyl in algæ and its absence in fungi. gelatinous starch is found in the algæ; the fungi contain a starchy substance called glycogen, which also occurs in the liver and muscles of animals. structureless bodies, as _æthalium_, contain no true sugar. stratified starch[ ] first appears in the phanerogams. alkaloids have been found in fungi, and owe their presence doubtless to the richness of these plants in nitrogenous bodies. in addition to the green coloring matter in algæ are found other coloring matters.[ ] the nature[ ] of these coloring matters is usually the same through whole families, which also resemble each other in their modes of reproduction. in form, the algæ differ greatly from filaments or masses of cells; they live in the water and cover damp surfaces of rocks and wood. in these they are remarkable for their ramifications and colors and grow to a gigantic size. the physiological functions of algæ and fungi depend upon their chemical differences. these facts have been offered, simple as they are, as striking examples of chemical and structural opposition. the fungi include very simple organisms, as well as others of tolerably high development, of most varied form, from the simple bacillus and yeast to the truffle, lichens, and mushrooms. the cell membrane of this class contains no pure cellulose, but a modification called fungus cellulose. the membrane also contains an amyloid substance, amylomycin.[ ] many of the chemical constituents found in the entire class are given in _die pflanzenstoffe_.[ ] under the _schizomycetes_ to which the _micrococcus_ and _bacterium_[ ] belong are found minute organisms differing much in form and in the coloring[ ] matters they produce, as that causing the red color of mouldy bread. the class of lichens[ ] contains a number of different coloring substances, whose chemical composition has been examined. these substances are found separately in individuals differing in form. in the _polyporus_[ ] an acid has been found peculiar to it, as in many plants special compounds are found. in the agariceæ the different kinds of vellum distinguish between species, and the color of the conidia is also of differential importance. in all cases of distinct characteristic habits of reproduction and form, one or more different chemical compounds is found. in the next group of the musiceæ, or mosses, is an absence of some chemical compounds that were characteristic of the classes just described. many of the albuminous substances are present. starch[ ] is found often in large quantities, and also oily fats, which are contained in the oil bodies of the liverworts; wax,[ ] organic acids, including aconitic acid, and tannin, which is found for the first time at this evolutionary stage of the plant kingdom. the vascular cryptogams are especially characterized by their mineral composition.[ ] the ash is extraordinarily rich in silicic acid and alumina. equisetum[ ]..........silicic acid per cent. aspidium............... " " asplenium.............. " " osmunda................ " " lycopodium[ ]......... " " " ........ alumina to " ........ manganese to . these various plants contain acids and compounds peculiar to themselves. as we ascend in the plant scale, we reach the phanerogams. these plants are characterized by the production of true seeds, and many chemical compounds not found in lower plants. it will be convenient in speaking of these higher groups to follow m. heckel's[ ] scheme of plant evolution. all these plants are grouped under three main divisions: apetalous, monocotyledonous, and dicotyledonous; and these main divisions are further subdivided. it will be observed that these three main parallel columns are divided into three general horizontal planes. on plane are all plants of simplicity of floral elements, or parts; for example, the black walnut, with the simple flower contained in a catkin. on plane plants which have a multiplicity of floral elements, as the many petals and stamens of the rose; and finally, the higher plants, the orchids among the monocotyledons and the composite among the dicotyledonous plants, come under the third division of condensation of floral elements. it will be impossible to take up in order for chemical consideration all these groups, and i shall restrict myself to pointing out the occurrence of certain constituents. i desire now to call attention to chemical groups under the apetalous plants having simplicity of floral elements. _cassuarina equisetifolia_[ ] possibly contains tannin, since it is used for curing hides. the bark contains a dye. it is said to resemble _equisetum_[ ] in appearance, and in this latter plant a yellow dye is found. the _myrica_[ ] contains ethereal oil, wax, resin, balsam, in all parts of the plant. the root contains in addition fats, tannin, and starch, also myricinic acid. in the willow and poplar,[ ] a crystalline, bitter substance, salicin or populin, is found. this may be considered as the first appearance of a real glucoside, if tannin be excluded from the list. the oak, walnut, beech, alder, and birch contain tannin in large quantities; in the case of the oak, ten to twelve per cent. oak galls yield as much as seventy per cent.[ ] the numerous genera of pine and fir trees are remarkable for ethereal oil, resin, and camphor. the plane[ ] trees contain caoutchouc and gum; peppers,[ ] ethereal oils, alkaloids, piperin, white resin, and malic acid. _datisca cannabina_[ ] contains a coloring matter and another substance peculiar to itself, datiscin, a kind of starch, or allied to the glucosides. upon the same evolutionary plane among the monocotyledons, the dates and palms[ ] contain in large quantities special starches, and this is in harmony with the principles of the theory. alkaloids and glucosides have not yet been discovered in them. other monocotyledonous groups with simplicity of floral elements, such as the typhaceæ, contain large quantities of starch; in the case of _typha latifolia_[ ] . per cent., and . per cent. gum. in the pollen of this same plant, . per cent. starch has been found. under the dicotyledonous groups, there are no plants with simplicity of floral elements. returning, now, to apetalous plants of multiplicity and simplification of floral elements, we find that the urticaceæ[ ] contain free formic acid; the hemp[ ] contains alkaloids; the hop,[ ] ethereal oil and resin; the rhubarb,[ ] crysophonic acid; and the begonias,[ ] chicarin and lapacho dyes. the highest apetalous plants contain camphors and oils; the highest of the monocotyledons contain a mucilage and oils; and the highest dicotyledons contain oils and special acids. the trees yielding common camphor and borneol are from genera of the lauraceæ family; also sassafras camphor is from the same family. small quantities of stereoptenes are widely distributed through the plant kingdom. the gramineæ, or grasses, are especially characterized by the large quantities of sugar and silica they contain. the ash of the rice hull, for example, contains ninety eight per cent. silica. the ranunculaceæ contain many plants which yield alkaloids, as _hydrastia canadensis_, or indian hemp, _helleborus_, _delphinum_, _aconitum_, and the alkaloid berberine has been obtained from genera of this family. the alkaloid[ ] furnishing families belong, with few exceptions, to the dicotyledons. the colchiceæ, from which is obtained veratrine, form an exception among the monocotyledons. the alkaloids of the fungus have already been noted. [ ]among the greater number of plant families, no alkaloids have been found. in the labiatæ none has been discovered, nor in the compositæ among the highest plants. one alkaloid is found in many genera of the loganiaceæ; berberine in genera of the berberidaceæ, ranunculaceæ, menispermaceæ, rutaceæ, papaveraceæ, anonaceæ. waxes are widely distributed in plants. they occur in quantities in some closely related families. ethereal oils occur in many families, in the bark, root, wood, leaf, flower, and fruit; particularly in myrtaceæ, laurineæ, cyperaceæ, crucifereæ, aurantiaceæ, labiatæ, and umbelliferæ. resins are found in most of the higher plants. tropical plants are richer in resins than those of cold climates. chemical resemblance between groups, as indicating morphological relations, has been well shown. for example: the similarity[ ] of the viscid juices, and a like taste and smell, among cactaceæ and portulaceæ, indicate a closer relationship between these two orders than botanical classification would perhaps allow. this fact was corroborated by the discovery of irritable stamens in _portulaca_ and _opuntia_, and other genera of cactaceæ. darwin[ ] states that in the compositæ the ray florets are more poisonous than the disk florets, in the ratio of about to . comparing the cycadeæ and palmæ, the former are differently placed by different botanists, but the general resemblance is remarkable, and they both yield sago. chemical constituents of plants are found in varying quantities during stated periods of the year. certain compounds present at one stage of growth are absent at another. many facts could be brought forward to show the different chemical composition of plants in different stages of growth. the _thuja occidentalis_[ ] in the juvenescent and adult form, offers an example where morphological and chemical differences go hand in hand. analyses of this plant under both conditions show a striking difference. different parts of plants may contain distinct chemical compounds, and the comparative chemical study of plant orders comprises the analysis of all parts of plants of different species. for example; four portions of the _yucca angustifolia_[ ] were examined chemically; the bark and wood of the root and the base and blades of the leaves. fixed oils were separated from each part. these were not identical; two were fluid at ordinary temperature, and two were solid. their melting and solidifying points were not the same. this difference in the physical character and chemical reaction of these fixed oils may be due to the presence of free fatty acid and glycerides in varying proportions in the four parts of the plants. it is of interest to note that, in the subterranean part of the _yucca_, the oil extracted from the bark is solid at the ordinary temperature; from the wood it was of a less solid consistency; while the yellow base of the leaf contained an oil quite soft, and in the green leaf the oil is almost fluid. two new resins were extracted from the yellow and green parts of the leaf. it was proposed to name them _yuccal_ and _pyrophæal_ an examination of the contents of each extract showed a different quantitative and qualitative result. saponin was found in all parts of the plant. many of the above facts have been collected from the investigations of others. i have introduced these statements, selected from a mass of material, as evidences in favor of the view stated at the beginning of this paper.[ ] my own study has been directed toward the discovery of saponin in those plants where it was presumably to be found. the practical use of this theory in plant analysis will lead the chemists at once to a search for those compounds which morphology shows are probably present. i have discovered saponin in all parts of the _yucca angustifolia_, in the _y. filimentosa_ and _y. gloriosa_, in several species of agavæ, and in plants belonging to the leguminosæ family. the list[ ] of plants in which saponin has been discovered is given in the note. all these plants are contained in the middle plane of heckel's scheme. no plants containing saponin have been found among apetalous groups. no plants have been found containing saponin among the lower monocotyledons. the plane of saponin passes from the liliaceæ and allied groups to the rosales and higher dicotyledons. saponin belongs to a class of substances called glucosides. under the action of dilute acids, it is split up into two substances, glucose and sopogenin. the chemical nature of this substance is not thoroughly understood. the commercial[ ] product is probably a mixture of several substances. this complexity of chemical composition of saponin is admirably adapted for the nutrition of the plant, and it is associated with the corresponding complexity of the morphological elements of the plant's organs. according to m. perrey,[ ] it seems that the power of a plant to direct the distribution of its carbon, hydrogen, and oxygen to form complex glucosides is indicative of its higher functions and developments. the solvent action of saponin on resins has been already discussed. saponin likewise acts as a solvent upon barium[ ] sulphate and calcium[ ] oxalate, and as a solvent of insoluble or slightly soluble salts would assist the plant in obtaining food, otherwise difficult of access. the botanical classifications based upon morphology are so frequently saponin is found in endogens and exogens. the line dividing these two groups is not always clearly defined. statements pointing to this are found in the works of haeckel, bentham, and others. smilax belongs to a transition class, partaking somewhat of the nature of endogen and of exogen. it is worthy of note that this intermediate group of the sarsaparillas should contain saponin. it is a significant fact that all the groups above named containing saponin belong to heckel's middle division. it may be suggested that saponin is thus a constructive element in developing the plant from the multiplicity of floral elements to the cephalization of those organs. it has been observed that the composite occurs where the materials for growth are supplied in greatest abundance, and the more simple forms arise where sources of nutrition are remote. we may gather from this fact that the simpler organs of plants low in the evolutionary scale contain simpler non-nitrogenous chemical compounds for their nutrition. the presence of saponin seems essential to the life of the plant where it is found, and it is an indispensable principle in the progression of certain lines of plants, passing from their lower to their higher stages. saponin is invariably absent where the floral elements are simple; it is invariably absent where the floral elements are condensed to their greatest extent. its position is plainly that of a factor in the great middle realm of vegetable life, where the elements of the individual are striving to condense, and thus increase their physiological action and the economy of parts. it may be suggested as a line of research to study what are the conditions which control the synthesis and gradual formation of saponin in plants. the simpler compounds of which this complex substance is built up, if located as compounds of lower plants, would indicate the lines of progression from the lower to the saponin groups. in my paper[ ] read in buffalo at the last meeting of the american association for the advancement of science, various suggestions were offered why chemical compounds should be used as a means of botanical classification. the botanical classifications based upon morphology are so frequently unsatisfactory, that efforts in some directions have been made to introduce other methods.[ ] there has been comparatively little study of the chemical principles of plants from a purely botanical view. it promises to become a new field of research. the leguminosæ are conspicuous as furnishing us with important dyes, e.g., indigo, logwood, catechin. the former is obtained principally from different species of the genus _indigofera_, and logwood from the _hæmatoxylon_ and _saraca indica_. the discovery[ ] of hæmatoxylin in the _saraca indica_ illustrates very well how this plant in its chemical, as well as botanical, character is related to the _hæmatoxylon campechianum_; also, i found a substance like catechin in the _saraca_. this compound is found in the _acacias_, to which class _saraca_ is related by its chemical position, as well as botanically. saponin is found in both of these plants, as well as in many other plants of the leguminosæ. the leguminosæ come under the middle plane or multiplicity of floral elements, and the presence of saponin in these plants was to be expected. from many of the facts above stated, it may be inferred that the chemical compounds of plants do not occur at random. each stage of growth and development has its own particular chemistry. it is said that many of the constituents found in plants are the result of destructive metabolism, and are of no further use in the plant's economy. this subject is by no means settled, and even should we be forced to accept that ground, it is a significant fact that certain cells, tissues, or organs peculiar to a plant secrete or excrete chemical compounds peculiar to them, which are to be found in one family, or in species closely allied to it. it is a fact that the chemical compounds are there, no matter why or whence they came. they will serve our purposes of study and classification. the result of experiment shows that the presence of certain compounds is essential to the vigor and development of all plants and particular compounds to the development of certain plants. plant chemistry and morphology are related. future investigations will demonstrate this relation. in general terms, we may say that amides and carbohydrates are utilized in the manufacture of proteids. organic acids cause a turgescence of cells. glucosides may be a form of reserve food material. resins and waxes may serve only as protection to the surfaces of plants; coloring matters, as screens to shut off or admit certain of the sun's rays; but we are still far from penetrating the mystery of life. a simple plant does what animals more highly endowed cannot do. from simplest substances they manufacture the most complex. we owe our existence to plants, as they do theirs to the air and soil. the elements carbon, oxygen, hydrogen, and nitrogen pass through a cycle of changes from simple inorganic substances to the complex compounds of the living cell. upon the decomposition of these bodies the elements return to their original state. during this transition those properties of protoplasm which were mentioned at the beginning, in turn, follow their path. from germination to death this course appears like a crescent, the other half of the circle closed from view. where chemistry begins and ends it is difficult to say.--_jour. fr. inst._ [footnote : a lecture delivered before the franklin institute, january , .] [footnote : studien uber das protoplasm, .] [footnote : vines, p. . rostafinski: mem. de la soc. des sc. nat. de cherbourg, . strasburger: zeitschr., xii, .] [footnote : botany: prantl and vines. london, , p. .] [footnote : for the literature of starch, see p. , die pflanzenstoffe, von hilger and husemann.] [footnote : kutzing: arch. pharm., xli, . kraus and millardet: bul. soc. sciences nat., strasbourg, , . sorby: jour. lin. soc., xv, . j. reinke: jahrb. wissenscht. botan., x, b. . phipson: phar. jour. trans., clxii, .] [footnote : prantl and vines, p. .] [footnote : l. crie: compt. rend., lxxxviii, and . j. de seynes, , .] [footnote : page .] [footnote : m. nencki and f. schaffer. n. sieher: jour. pract. chem., , .] [footnote : e. klein: quar. jour. micros. science, , . o. helm: arch. pharm., , - . g. gugini: gaz. chem., , . w. thorner: bul. ber, xi, .] [footnote : handbook of dyeing. by w. crookes, london, . p. . schunck: ann. chem. pharm., , ; , ; , ; , ; , . rochelder and heldt, ibid., , ; , . stenhouse, ibid., , ; , ; , , ; , . see also researches of strecker, o. hesse, reymann, liebermann, lamparter, knop, and schnedermann.] [footnote : stahlschmidt.] [footnote : e. treffner: inaugur. diss. dorpat, .] [footnote : w. pfeffer: flora, .] [footnote : die pflanzenstoffe, p. w. lange: bul. ber., xi, .] [footnote : ann. chim. phys., , , ; ann. chim. pharm., , .] [footnote : fluckiger: pharmakognosie. kamp: ann. chim. pharm., , .] [footnote : revue scientifiqe, mars, .] [footnote : dictionary of economic plants. by j. smith. london, , p. .] [footnote : ibid., p. . pharmakognosie des pflanzenreichs, wittstein, p. . ann. chem. pharm., , .] [footnote : rabenhorst: repert. pharm., lx, . moore: chem. centralbl., , , dana.] [footnote : johansen: arch. pharm., , ix, . ibid., , ix . bente: berl. ber., viii, . braconnot: ann. chim. phys., , , .] [footnote : wittstein; pharm. des pflanzenreichs, p. .] [footnote : john; ibid., p. .] [footnote : dulong. oersted, lucas, pontet; ibid., p. .] [footnote : braconnot: ann. chim. phys., , . . stenhouse: ann. chim. phann., , ]. [footnote : pflanzenstoffe, p. .] [footnote : lecocq: braconnot: pharmacog. pflan, p. .] [footnote : gorup-besanez.] [footnote : siebold and brodbury: phar. jour. trans., , , , .] [footnote : wagner: jour. prakt. chem., , . b. peters, v. gohren: jahresb. agric., viii, ; ix, ; v. . ann. jour. pharm., , .] [footnote : dragendorff: pharm. zeitschr. russ., xvii, - .] [footnote : bonssingault: ann. chim. phys., , , . erdmann: jour. pract. chem., , .] [footnote : die pflanzenstoffe, p. .] [footnote : ibid.] [footnote : meehan: proc. acad. nat. sciences.] [footnote : different forms of flowers on plants of the same species. introduction.] [footnote : meehan: proc. acad. nat. sciences.] [footnote : h.c. de s. abbott: trans. amer. philos. soc., .] [footnote : for further facts confirming this theory, see "comparative chemistry of higher and lower plants." by h.c. de s. abbott. amer. naturalist, august, .] [footnote : different genera and species of the following: ranunculaceæ, berberidaceæ, carophyllaceæ, polygalaceæ, bromeliaceæ, liliaceæ, smilaceæ, yuccas, amaryllideæ, leguminosæ, primulaceæ, rosaceæ, sapindaceæ, sapotaceæ] [footnote : kobert: chem ztg.] [footnote : compt. rend., xciv, p. .] [footnote : bul. de la soc. chim.] [footnote : "yucca angus." trans. am. philos. soc., dec., .] [footnote : botanical gazette, october, .] [footnote : borodin: pharm. jour. trans., xvi, . pax. firemy: ann. sci. nat., xiii.] [footnote : h.c. de s. abbott, proc. acad. nat. sciences, nov. , .] * * * * * new method for the quantitative determination of starch. a.v. asboth. the author maintains that unsatisfactory results are obtained in determinations of starch when the method employed is based upon the inversion of sugar, formed as an intermediate product, since maltose, dextrose, and levulose are partly decomposed by boiling with dilute acids. he proposes to replace the methods hitherto employed by one which depends upon the formation of a barium salt of starch, to which he assigns the formula bao.c_{ }h_{ }o_{ }. this salt is sparingly soluble in water and insoluble in dilute alcohol. in making a determination a weighed quantity of starch is saccharified with water, then mixed with an excess of normal baryta solution, dilute alcohol added to make up to a certain volume, and, after the precipitate has settled, the excess of baryta is titrated back with acid. [illustration: titrating apparatus] the author also describes the apparatus he employs for storing and titrating with baryta solution. the latter is contained in the bottle, a, and the drying tube attached to the neck of the same is filled with quicklime. the burette, b, which is in direct connection with the bottle, may be filled with the solution by opening the stop cock, and the small drying tube, _n_, is filled with dry koh, thus preventing the entrance of any co_{ }. numbers are appended which seem to testify to the excellence of the method employed. the author finally gives a detailed account of the entire analysis of various cereals.--_a.r. in jour. soc. chem. indus._ * * * * * synthesis of the alkaloids. in the note on the constitution of alkaloids in a recent issue, we referred more especially to what we may term the less highly organized bases. most of our knowledge, as we now have it, regarding such alkaloids as muscarine and choline has been acquired during the past dozen years. this is not exactly the case with the higher groups of alkaloids--the derivatives of pyridine and quinoline. it so happens that the oldest alkaloids are in these groups. they have, almost necessarily, been subjected to a longer period of attack, but the extreme complexity of their molecules, and the infinite number of differing parts or substances into which these molecules split up when attacked, are the main cause of the small progress which has been made in this department. all, however, yield one or more bodies or bases in common, while each has its distinctive and peculiar decomposition product. for example, cinchonine and quinine both afford the basic quinoline under certain conditions, but on oxidation of cinchonine, an acid--cinchoninic acid (c_{ }h_{ }no_{ })--is the principal body formed, while in the case of quinine, quininic acid (c_{ }h_{ }no_{ }) is the principal product. the acquirement through experiment of such knowledge as that is, however, so much gained. we find, indeed, that obstacles are gradually being cleared away, and the actual synthetic formation of such alkaloids as piperidine and coniine is a proof that the chemist is on the right track in studying the decomposition products, and building up from them, theoretically, bodies of similar constitution. it is noteworthy that the synthesis of the alkaloids has led to some of the most brilliant discoveries of the present day, especially in the discovery of dye stuffs. many of our quinine substitutes, such as thalline, for example, are the result of endeavors to make quinine artificially. if there is romance in chemistry at all, it is to be found certainly in this branch of it, which is generally considered the most uninteresting and unfathomable. we may take piperidine and coniine as examples of the methods followed in alkaloidal synthesis; these are pyridine bases. pyridine has the formula c_{ }h_{ }n, that is, it is benzene with ch replaced by n. the relationship between these and piperidine is seen in the following formulæ: ch n nh / \ / \ / \ hc ch hc ch h_{ }c ch_{ } | | | | | | hc ch hc ch h_{ }c ch_{ } \ / \ / \ / ch ch ch_{ } (benzene,) (pyridine,) (piperidine,) (c_{ }h_{ }) (c_{ }h_{ }n) (c_{ }h_{ }n) if we introduce six hydrogen atoms into pyridine, we convert it into piperidine. ladenburg succeeded in so hydrogenizing pyridine by acting upon an alcoholic solution with sodium, and from the base which was formed he obtained a platinochloride which agreed with the similar double salt of piperidine. he has also prepared it from trimethyline cyanide by the action of sodium. pentamethylinediamine is the principal intermediary product, and this gives piperidine when distilled with superheated steam. he has proved that the alkaloid so obtained is identical with that prepared from piperine. another curious point which ladenburg has lately proved is that cadaverine (one of the products of flesh decomposition) is identical with pentamethylinediamine, and that its imine is the same as piperidine. the synthesis of coniine by ladenburg is one of the most notable achievements of modern chemistry. he at first supposed that this alkaloid was piperidine in which two hydrogen atoms were replaced by the isopropyl radical (c_{ }h_{ }), its formula being taken as c_{ }h_{ }(c_{ }h_{ })nh. but he has since changed his view, as will be seen from what follows. in its synthesis , grammes of picoline were first converted into alphapicoline, grammes being obtained. this was heated with paraldehyde, whereby it was converted into allylpyridine ( grammes), and this by reduction with sodium yielded alpha-propylpyridine, a body in almost every respect identical with coniine. the more important difference was its optical inactivity, but he succeeded in splitting up a solution of the acid tartrate of the base by means of _penicillium glaucum_. crystals separated which had a dextro-rotatory power of [_a_]_{d} = ° ' as compared with the [_a_]_{d} = ° ' of natural coniine. this brief account conveys but a faint idea of the difficulties which were encountered in these researches. optical methods of examination have proved of great value, and are destined to play an important part in such work. among the most complex alkaloids are those of the quinine group. as yet chemists have got no further with these than the oxidation products; but the study has afforded us several new antipyretics and many interesting facts. it has been found, for example, that artificial quinine-like bodies, which fluoresce and give the green color with chlorine water and ammonia, have antipyretic properties like quinine, but their secondary effects are so pernicious as to prevent their use. if, however, such bodies are hydrogenized or methylated they lose their fluorescing property, do not give the green color, and their secondary effects are removed. knowledge of these facts led to the discovery of thalline. it is prepared from paraquinanisol, one of the objectionable bodies, by reduction with tin and hydrochloric acid. the following formulæ show the constitutional relationship of these compounds: ch ch ch ch_{ } / \ / \ / \ / \ (ch_{ }o)c c ch (ch_{ }o)c c ch_{ } | | | | | | hc c ch hc c ch_{ } \ / \ / \ / \ / ch n ch nh paraquinanisol thalline c_{ }h_{ }.ch_{ }.no. c_{ }h_{ }.ch_{ }.no. it is evident from the difficulties which have been encountered in this department of chemistry, and more especially from the costly nature of the work, that it will be many years before it will influence the manufacture of alkaloids from the drugs which yield them. ladenburg has synthetized coniine, but he has not yet ventured to assert that his product will replace the natural alkaloid.--_chem. and druggist._ * * * * * the _southern california advocate_ reports another magnificent donation of lands to the university of southern california by mr. d. freeman, the owner of the centinella ranch near los angeles--six hundred thousand dollars in all given to found a school of applied sciences, $ , for building and apparatus and $ , for endowment. the buildings will be in the vicinity of inglewood, the new and beautiful town on the ballona branch of the california central. * * * * * a group of hampshire downs. [illustration] the hampshire down breed of sheep originated about years ago by a cross of south downs on the horned, white-faced sheep which had for ages been native of the open, untilled, hilly stretch of land known as the hampshire downs, in the county of that name bordering on the english channel, in the south of england. from time immemorial the south downs had dark brown or black legs, matured early, produced the best of mutton and a fine quality of medium wool. the original hampshire was larger, coarser, but hardier, slower to mature, with inferior flesh, and a longer but coarser wool. the south down has always been remarkable for its power of transmitting its special characteristics to its progeny by other kinds of sheep, and hence it soon impressed its own characteristics on its progeny by the hampshire. the horns of the original breed have disappeared; the face and legs have become dark, the frame has become more compact, the bones smaller, the back broader and straighter, the legs shorter, and the flesh and wool of better quality, while the superior hardiness and greater size, as well as the large head and roman nose of the old breed, still remain. the hampshires of to-day mature early and fatten readily. they clip from six to seven pounds of wool, suitable for combing, which is longer than south down wool, but less fine. the mutton has a desirable proportion of fat and lean, and is juicy and fine flavored. the lambs are of large size and are usually dropped early and fed for market. indeed, the hampshire may be considered a larger and trifle coarser and hardier south down. the breed is occasionally crossed with cotswolds, when it produces a wool more valuable for worsted manufacturers than the pure cotswold. indeed, there is little doubt that in addition to south down, the hampshire has a dash of cotswold blood in its composition. considerable importations of the breed have been made into this country, but it has not become so popular as the south down and some other english breeds. the excellent group shown is owned by mr. james wood, of mount kisco, new york.--_rural new-yorker._ * * * * * the yale college measurement of the pleiades.[ ] [footnote : "determination of the relative positions of the principal stars in the group of the pleiades." by william l. elkin. transactions of the astronomical observatory of yale university, vol. i., part i. (new haven: .)] the messrs. repsold have established, and for the present seem likely to maintain, a practical monopoly in the construction of heliometers. that completed by them for the observatory of yale college in leaves so little to be desired as to show excellence not to be the exclusive result of competition. in mere size it does not indeed take the highest rank. its aperture is of only six inches, while that of the oxford heliometer is of seven and a half; but the perfection of the arrangements adapting it to the twofold function of equatorial and micrometer stamps it as a model not easy to be surpassed. steel has been almost exclusively used in the mounting. recommended as the material for the objective cell by its quality of changing volume under variations of temperature nearly _paripassu_ with glass, its employment was extended to the telescope tube and other portions of the mechanism. the optical part of the work was done by merz, alvan clark having declined the responsibility of dividing the object lens. its segments are separable to the extent of °, and through the contrivance of cylindrical slides (originally suggested by bessel) perfect definition is preserved in all positions, giving a range of accurate measurement just six times that with a filar micrometer. (gill, "encyc. brit.," vol. xvi., p. ; fischer, _sirius_, vol. xvii., p. .) this beautiful engine of research was in placed in the already practiced and skillful hands of dr. elkin. he lost no time in fixing upon a task suited both to test the powers of the new instrument and to employ them to the highest advantage. the stars of the pleiades have, from the earliest times, attracted the special notice of observers, whether savage or civilized. hence, on the one hand, their prominence in stellar mythology all over the world; on the other, their unique interest for purposes of scientific study and comparison. they constitute an undoubted cluster; that is to say, they are really, and not simply in appearance, grouped together in space, so as to fall under the sway of prevailing mutual influences. and since there is, perhaps, no other stellar cluster so near the sun, the chance of perceptible displacements among them in a moderate lapse of time is greater than in any other similar case. authentic data regarding them, besides, have now been so long garnered that their fruit may confidently be expected at least to begin to ripen. dr. elkin determined, accordingly, to repeat the survey of the pleiades executed by bessel at konigsberg during about twelve years previous to . wolf and pritchard had, it is true, been beforehand with him; but the wide scattering of the grouped stars puts the filar micrometer at a disadvantage in measuring them, producing minute errors which the arduous conditions of the problem render of serious account. the heliometer, there can be no doubt, is the special instrument for the purpose, and it was, moreover, that employed by bessel; so that the konigsberg and yale results are comparable in a stricter sense than any others so far obtained. one of bessel's fifty-three stars was omitted by dr. elkin as too faint for accurate determination. he added, however, seventeen stars from the bonn _durchmusterung_, so that his list comprised sixty-nine, down to . magnitude. two independent triangulations were executed by him in - . for the first, four stars situated near the outskirts of the group, and marking the angles of quadrilateral by which it was inclosed, were chosen as reference points. the second rested upon measures of distance and position angle outward from alcyone ([eta] tauri). thus, two wholly unconnected sets of positions were secured, the close accordance of which testified strongly to the high quality of the entire work. they were combined, with nearly equal weights, in the final results. a fresh reduction of the konigsberg observations, necessitated by recent improvements in the value of some of the corrections employed, was the preliminary to their comparison with those made, after an interval of forty-five years, at yale college. the conclusions thus laboriously arrived at are not devoid of significance, and appear perfectly secure, so far as they go. it has been known for some time that the stars of the pleiades possess a small identical proper motion. its direction, as ascertained by newcomb in , is about south-southeast; its amount is somewhat less than six seconds of arc in a century. the double star cygni, in fact, is displaced very nearly as much in one year as alcyone with its train in one hundred. nor is there much probability that this slow secular shifting is other than apparent; since it pretty accurately reverses the course of the sun's translation through space, it may be presumed that the _backward_ current of movement in which the pleiades seem to float is purely an effect of our own _onward_ traveling. now the curious fact emerges from dr. elkin's inquiries that six of bessel's stars are exempt from the general drift of the group. they are being progressively left behind. the inference is obvious that they do not in reality belong to, but are merely accidentally projected upon, it; or, rather, that it is projected upon them; for their apparent immobility (which, in two of the six, may be called absolute) shows them with tolerable certainty to be indefinitely more remote--so remote that the path, moderately estimated at , , , miles in length, traversed by the solar system during the forty-five years elapsed since the konigsberg measures dwindles into visual insensibility when beheld from them. the brightest of these six far-off stars is just above the eighth ( . ) magnitude; the others range from . down to below the ninth. a chart of the relative displacements indicated for bessel's stars by the differences in their inter-mutual positions as determined at konigsberg and yale accompanies the paper before us. divergences exceeding . " (taken as the limit of probable error) are regarded as due to real motion; and this is the case with twenty-six stars besides the half dozen already mentioned as destined deserters from the group. with these last may be associated two stars surmised, for an opposite reason, to stand aloof from it. instead of tarrying behind, they are hurrying on in front. an excess of the proper movement of their companions belongs to them; and since that movement is presumably an effect of secular parallax, we are justified in inferring their possession of an extra share of it to signify their greater proximity to the sun. hence, of all the stars in the pleiades these are the most likely to have a measurable annual parallax. one is a star a little above the seventh magnitude, distinguished as _s_ pleiadum; the other, of about the eighth, is numbered in bessel's list. dr. elkin has not omitted to remark that the conjecture of their disconnection from the cluster is confirmed by the circumstance that its typical spectrum (as shown on prof. pickering's plates) is varied in _s_ by the marked character of the k line. the spectrum of its fellow traveler (no. ) is still undetermined. it is improbable, however, that even these nearer stars are practicable subjects for the direct determination of annual parallax. by indirect means, however, we can obtain some idea of their distance. all that we want to know for the purpose is the _rate_ of the sun's motion; its _direction_ we may consider as given with approximate accuracy by airy's investigation. now, spectroscopic measurements of stellar movements of approach and recession will eventually afford ample materials from which to deduce the solar, velocity; though they are as yet not accurate or numerous enough to found any definitive conclusion upon. nevertheless, m. homann's preliminary result of fifteen miles a second as the speed with which our system travels in its vast orbit inspires confidence both from the trustworthiness of the determinations (mr. seabroke's) serving as its basis and from its intrinsic probability. accepting it provisionally, we find the parallax of alcyone = about . ', implying a distance of , , , , miles and a light journey of years. it is assumed that the whole of its proper motion of . ' in forty-five years is the visual projection of oar own movement toward a point in r.a. °, decl. + °. thus the parallax of the two stars which we suspect to lie between us and the stars forming the genuine group of the pleiades, at perhaps two-thirds of their distance, can hardly exceed . '. this is just half that found by dr. gill for [xi] toucani, which may be regarded as, up to this, the smallest annual displacement at all satisfactorily determined. and the error of the present estimate is more likely to be on the side of excess than of defect. that is, the stars in question can hardly be much nearer to us than is implied by an annual parallax of . ", and they may be considerably more remote. dr. elkin concludes, from the minuteness of the detected changes of position among the pleiades, that "the hopes of obtaining any clew to the internal mechanism of this cluster seem not likely to be realized in an immediate future;" remarking further: "the bright stars in especial seem to form an almost rigid system, as for only one is there really much evidence of motion, and in this case the total amount is barely per century." this one mobile member of the naked eye group is electra; and it is noticeable that the apparent direction of its displacement favors the hypothesis of leisurely orbital circulation round the leading star. the larger movements, however, ascribed to some of the fainter associated stars are far from harmonizing with this preconceived notion of what they ought to be. on the contrary, so far as they are known at present, they force upon our minds the idea that the cluster may be undergoing some slow process of disintegration. m. wolf's impression of incipient centrifugal tendencies among its components certainly derives some confirmation from dr. elkin's chart. divergent movements are the most strongly marked; and the region round alcyone suggests, at the first glance, rather a very confused area of radiation for a flight of meteors than the central seat of attraction of a revolving throng of suns. there are many signs, however, that adjacent stars in the cluster do not pursue independent courses. "community of drift" is visible in many distinct sets; while there is as yet no perceptible evidence, from orbital motion, of association into subordinate systems. the three eighth-magnitude stars, for instance, arranged in a small isosceles triangle near alcyone, do not, as might have been expected _a priori_, constitute a real ternary group. they are all apparently traveling directly away from the large star close by them, in straight lines which may, of course, be the projections of closed curves; but their rates of travel are so different as to involve certain progressive separation. obviously, the order and method of such movements as are just beginning to develop to our apprehension among the pleiades will not prove easy to divine.--_a.m. clerke, in nature._ * * * * * deep sea dredgings: examination of sea bottoms. by thomas t.p. bruce warren. i believe prof. ehrenberg was one of the first to examine, microscopically, deep sea dredgings, some of which were undertaken for the atlantic cable expedition, . i propose to deal with the bottoms brought up from tropical waters of the atlantic, a few years ago, during certain telegraph cable operations. these soundings were made for survey purposes, and not for any biological or chemical investigations. still i think that this imperfect record may be a useful contribution to chemical science, bearing especially on marine operations. although there is little to be added to the chemistry of this subject, still i think there are few chemists who could successfully make an analysis of a deep sea "bottom" without some sacrifice of time and patience, to say nothing of the risk of wasting a valuable specimen. the muds, clays, oozes, etc., from deep water are so very fine that they pass readily through the best kinds of filters, and it is necessary to wash out all traces of sea water as a preliminary. the specimen must be _repeatedly_ washed by decantation, until the washings are perfectly free from chlorine, when the whole may be thrown onto a filter _merely_ to drain. the turbid water which passes through is allowed to stand so that the suspended matter may settle, and after decanting the clear supernatant water, the residuum is again thrown on to the filter. the washing and getting ready for the drying oven will, in some cases, require days to carry out, if we wish to avoid losing anything. so far the proceeding is exactly the same, except draining on a filter, which would be adopted for preparing for the microscope. on no account should the opportunity be missed of mounting several slides permanently for microscopic examination. drawings or photographic enlargements will render us independent of direct microscopic appeal, which is not at all times convenient. the substance, if drained and allowed to dry on the filter, will adhere most tenaciously to it, so that it is better to complete the drying in a porcelain or platinum capsule, either by swilling the filter with a jet of water or by carefully removing with a spatula. the most strenuous care must be used not to contaminate the specimen with loose fibers from the filter. the perfectly dried matter is best treated in exactly the same way as a residuum in water analysis. it is a common thing to ignite the residuum, and to put the loss down, if any, to water. this ought not to satisfy an accurate observer, since organic matter, carbonates--especially in presence of silica--will easily add to the loss. the best plan is to heat a small portion very cautiously, and note if any smell or alteration in color, due to carbon, etc., is perceptible, and to proceed accordingly. i have seen some very satisfactory analyses made on board ship by a skillful use of the blowpipe, where liquid reagents would be very inconvenient to employ. it will be necessary to say a few words as to the way in which soundings are made at sea. when the bottom consists of sand, mud, or other loose matter, it is easy enough to bring specimens to the surface, and, of course, we know in such a case that the bottom has been reached, but, in the event of the bottom being hard and rocky, it is not easy to say that our sounding has been successful: and here we meet with a difficulty which unfortunately is most unsatisfactorily provided for. the lead is "cast," as the saying goes, "armed" for this emergency. an iron sinker is made with a hollow recess in the bottom; this is filled in with tallow, and on striking the bottom any loose matter may adhere by being pressed into the tallow. if the bottom is rocky or hard we get simply an imprint in the arming, and when such a result is obtained the usual construction is that "the bottom is rocky" or hard. now, this seems to me a point on which chemistry may give some very valuable help, for i am convinced that no sounding should be accepted unless evidence of the bottom itself is obtained. a few considerations will show that when we are working in very deep water, where there is a difficulty of knowing for certain that we have an "up and down" sounding, and the hardening of the "arming" by the cold and pressure, unless we bring up something we cannot be sure that we have touched the bottom; leaving the doubt on this point on one side, unless we use a very heavy sinker, so as to get an indication of the released strain when it touches the bottom, we encounter another complication. sir william thomson's sounding wire has added the element of reliability to our soundings in this latter case. the note given out by the wire when the bottom is reached is perceptibly different when under strain, even if the dynamometer should give an unreliable indication. it has been found that when a "bottom" has been recovered by the arming with tallow, the adherent grease seriously detracts from the value of the specimen for scientific purposes. washing with perfectly pure bisulphide carbon will save the sounding, but of course any living organism is destroyed. as we have plenty of contrivances for bringing up loose "bottoms" without arming, we have nothing to fear on this score. there is a great difficulty to explain the vast accumulations of clay deposits on the ocean bed, and it has been suggested that some minute organisms may produce these deposits, as others give us carbonate of lime. is there not a very great probability of some of the apparently insoluble rocky formations being answerable for these accumulations? we must not forget the peculiar changes which such an apparently stable substance as feldspar undergoes when disintegrated and exposed to the chemical action of sea water. as these deposits contain both sodium and potassium, our chemical operations must provide for the analytical results; in other respects the analysis can be proceeded with according to the operator's analytical knowledge. few operators are aware of the usefulness of an ordinary deep sea grapnel rope, as used for cable work, in recovering specimens of the fauna of any locality. the grapnel rope should be left down for a few months, so that the denizens of the deep may get used to it and make it their place of residence and _attachment_. the stench caused by their decomposition, unless the rope be kept in water, when hauled up will be in a few days intolerable, even to an individual with a sea-going stomach. i tried several chemical solutions for preserving specimens thus recovered, but nothing answered so well as the water itself drawn up from the same depth as the rope was recovered from.--_chem. news._ * * * * * the scientific american architects and builders edition $ . a year. single copies, cts. this is a special edition of the scientific american, issued monthly--on the first day of the month. each number contains about forty large quarto pages, equal to about two hundred ordinary book pages, forming, practically, a large and splendid magazine of architecture, richly adorned with _elegant plates in colors_ and with fine engravings, illustrating the most interesting 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[new series.] _thirty-second year_. new york, saturday, february , . * * * * * contents. (illustrated articles are marked with an asterisk.) academy of sciences, new york. answers to correspondents. arts, lost, in new york. augers and drills ( ). bain, alexander. blue glass deception, the. blue glass science. boilers for small engines ( , ). business and personal. caffeone. chromate of lime, acid ( ). circle problem, the three ( ). clock collector, a. coal, burning small ( ). cremation temple, proposed*. dark days ( ). dates and the date palm*. diseases, infections. dyeing process, a cold ( ). engines for boats ( ). floors, filling for hardwood ( ). friction at rest ( ). frost plant of russia, the*. glass making, toughened. greenhouses, tar paint in ( ). harness cockeye, improved*. heating ranges ( ). heating rooms ( ). hemi-plunger, the.* hens, leghorn. ink, purple marking. iron trade in england. laboratory manipulations. lathe chuck.* lathe, screw-cutting.* lead, sea water and. moneyed men. mortar, black ( ). new books and publications. ornaments in winter, natural. papin's steam engine.* patent decision, a. patent matters in washington. patent office annual report. patents, american and foreign. patents, official list of. planing mill machinery. posterity, for--a suggestion. railroad, the wetli mountain.* rock sections for microscopy. roofs, leaky slate ( ). rose bushes, soot for. salicylic acid for the feet. sawdust in rough casting. seed-distributing panthers. self-reliance and success. snow a fertilizer. something to do. spectroscope prisms ( ). steam engine, papin's. steam engine, the brown. suicide statistics. telegraph, the speaking. trolling hook, improved*. watch, position of a ( ). waterproofing, suint for. white color in animals. wire, crossing a river on a. wool, purifying. zinc roofs ( ). * * * * * table of contents of the scientific american supplement, no. , for the week ending february , . i. engineering and mechanics.--artificial production of ice by steam power--the american roller skate rink, paris, engraving.--the little basses light house, figures.--the souter point electric light.--on the minute measurements of modern science, by alfred mayer.--method of measuring by means of the micrometer screw furnished with the contact level; method of electric contact applied to measurements with the micrometer screw, engravings.--abstracts from report of the boston society of civil engineers on the metric system.--new turret musical and chiming clock for the bombay university, with page of engravings.--water gas and its advantages, by geo. s. dwight.--brattice cloths in mines.--eight horse power portable steam engine, with dimensions, particulars, and page of engravings.--clyde ship building and marine engineering in .--four masted ships.--new bridges at and near new york city.--the sutro tunnel.--independent car wheels.--passenger travel, new york city. ii.--technology.--design for iron stairway, and iron grilles, with engravings.--the process of micro-photography used in the army medical department.--direct positives for enlarging.--a monster barometer.--architectural science, carpentry queries and replies.--the carpet manufactures of philadelphia. how the centre selvage is formed, figures.--glass of the ancients.--on the preservation of meat; 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[hand->] single copies of any desired number of the supplement sent to any address on receipt of cents. * * * * * publishers' notice. new subscriptions to the scientific american and the scientific american supplement will, for the present, be entered upon our books to commence with the year, and the back numbers will be sent to each new subscriber unless a request to the contrary accompanies the order. instead of a notice being printed on the wrapper, announcing that a subscription is about to end, the time of expiration is now denoted in the printed address each week, so that the subscriber may see when the period for which he has prepaid is about to expire. * * * * * dates and the date palm. even those whose knowledge of the customs of the orient extends no further than a recollection of the contents of that time-honored story book, the "arabian nights," are doubtless aware that, since time immemorial, the date has been the chief food staple of the desert-dwellers of the east. the "handful of dates and gourd of water" form the typical meal and daily sustenance of millions of human beings both in arabia and in north africa, and to this meager diet ethnologists have ascribed many of the peculiar characteristics of the people who live upon it. buckle, who finds in the constant consumption of rice among the hindoos a reason for the inclination to the prodigious and grotesque, the depression of spirits, and the weariness of life manifest in that nation, likewise considers that the morbid temperament of the arab is a sequence of vegetarianism. he points out that rice contains an unusual amount of starch, namely, between and per cent; and that dates possess precisely the same nutritious substances as rice does, with the single difference that the starch is already converted into sugar. to live, therefore, on such food is not to satisfy hunger; and hunger, like all other cravings, even if partially satisfied, exercises control over the imagination. "this biological fact," says peschel, "was and still is the origin of the rigid fastings prescribed by religions so widely different, which are made use of by shamans in every quarter of the world when they wish to enter into communication with invisible powers." peschel and buckle, however, are at variance as to the influence of the date diet as affecting a race; and the former remarks that, "while no one will deny that the nature of the food reacts upon the mental powers of man, the temperament evoked by different sorts is different;" yet "we are still far from having ascertained anything in regard to the permanent effects of daily food, especially as the human stomach has, to a great degree, the power of accommodating itself to various food substances, so that with use even narcotics lose much of their effect." the same author also adds that the date "trains up independent and warlike desert tribes, which have not the most remote mental relationship to the rice-eating hindoos." it remains for the reader to reconcile this disagreement of learned doctors according to his own judgment. the evidence of those who subsist on the date is certainly overwhelming in its favor. the assyrians, tradition says, asserted that it was such a great gift to them that its worth could not be too extravagantly told; for they had found, for the leaves, the fruit, the juices, and the wood of the tree, three hundred and sixty different uses. the mohammedans adopt the date palm into their religion as an emblem of uprightness, and say that it miraculously sprang into existence, fully grown, at the command of the prophet. palm branches still enter as symbols of rejoicing into christian religious ceremonies; and throughout palestine constant reference is found to the date and the palm in the naming of towns. bethany means "a house of dates." ancient palmyra was a "city of palms," and the hebrew female name tamar is derived from the word in that language signifying palm. in africa there is an immense tract of land between barbary and the great desert named bilidulgerid, "the land of dates," from the profusion of the trees there growing. [illustration: gathering dates in ceylon.] in this country, the date as an article of food is classed with the prune, the fig, and the tamarind, to be used merely as a luxury. we find it coming to the markets at just about this time of year in the greatest quantities, packed in baskets roughly made from dried palm leaves. the dates, gathered while ripe and soft, are forced into these receptacles until almost a pasty mass, often not over clean, is formed. their natural sugar tends to preserve them; but after long keeping they become dry and hard. this renders them unfit for use; but they still find a sale to the itinerant vendors who, after steaming them to render them soft (of course at the expense of the flavor), hawk them about the streets. dates in the pasty condition are not relished by those who live on them; nor, on the other hand, would we probably fancy the dried, almost tasteless fruit which, strung on long straws, is carried in bunches by the arabs in their pouches. the date palm (_phoenix dactylifera_) is the most important species of the dozen which make up its genus. though slow in growth, it shoots up a magnificent stem, to the height sometimes of eighty feet, the summit of which is covered with a graceful crown of pinnated leaves. the trunk is exceedingly rough and spiny; the flower spathes, which appear in the axils of the leaves, are woody, and contain branched spadices with many flowers; more than , have been counted on a single male spadix. as the flowers are dioecious, it is necessary to impregnate the female blossoms artificially in order to insure a good crop; and to this end the male spadices are cut off when the pollen is ripe and carefully shaken over the female ones. at from six to ten years of age, the tree bears, and then remains fruitful for upward of years. an excellent idea of the palm in full bearing may be obtained from our illustration, which represents the mode of gathering the dates, of which a single tree will often yield from one to four hundredweight in a season. the fruit varies much in size and quality; and in the oases of the sahara forty-six varieties have been named. the utilizations of the date palm and its products are very numerous. the stem yields starch, and timber for houses, boats, fences, fuel, etc., as well as an inferior kind of sago. the leaves serve as parasols and umbrellas, and for material for roof covering, baskets, brushes, mats, and innumerable utensils. at their base is a fiber, which is spun into excellent rope. when the heart of the leaf is cut, a thick honey-like juice exudes, which, by fermentation, becomes wine (the "toddy" of india), or vinegar, and is also boiled down into sugar. the young shoots, when cooked, resemble asparagus; and the dates themselves are dried and ground into meal, from which bread is prepared. * * * * * panthers as seed distributors. it is well known that bees carry pollen from flower to flower, and that eggs of marine animals are often carried long distances in the stomachs of aquatic birds. a very curious instance of this kind, showing how vegetable species may be diffused by means which no botanist, however acute, would be likely to think of, is mentioned by mr. alfred smee, who states that, attached to the skin of a panther recently shot in india, were found numerous seeds, each of which had two perfect hooks, manifestly designed to attach themselves to foreign bodies. as the panther moved about it collected the seeds on the skin and carried them about wherever it went; but when it rubbed against the shrubs, it of necessity brushed some off, and thus distributed them. one of the seeds produced a handsome plant, and beautiful clusters of tubular flowers. it was immediately recognized to be the _martynia diandra_--a plant which, although introduced into england as far back as , has scarcely ever been cultivated, although it has been commented on by botanists and other writers. * * * * * for posterity--a suggestion. the irish gentleman who declined to aid an enterprise for the benefit of posterity, remarking that posterity had never done anything for him, was, after all the sport made of him, no unfair representative of the bulk of mankind. there is talk enough about doing great things for the advantage of future ages, but the real motive is apt to be something very different. to perpetuate their own name or fame, men or nations often set up lasting monuments, and sometimes unintentionally convey thereby to after times a few more or less instructive indications of the artistic or industrial skill of their day and generation. to further their own immediate ends, or to secure some benefit to their immediate descendants, men frequently undertake great material enterprises, and sometimes the work so done remains for ages the source of perennial good. but very rarely, if ever, can it be said that any work of man was undertaken solely, or even chiefly, for the benefit of posterity--more rarely still, for remote posterity. hence it happens that we owe far more to accident, to fire, rapine, volcanic outbursts, and the protecting care of desolation, for the knowledge we have of times long past, than to any intentional legacies of art or learning left us by the men of those times. the lost and abandoned tools, weapons, and ornaments of the stone age are all that we have to tell us of the childhood of humanity. had no fiery disasters ever overtaken the pile-dwellers of the swiss lakes, we should probably have never heard of such a people. to the mud and ashes of vesuvius, rather than to the historians of the roman empire, we owe the best of our knowledge of how roman cities looked and roman citizens lived eighteen hundred years ago. in the fragments of a _terra cotta_ library, buried in the ruins of a royal palace, we find almost our only records of the arts and sciences of ancient assyria. under the ash heaps of a forgotten age, in cyprus, cesnola finds the only known vestiges of a primitive civilization, reaching far back into the domain of mythology. thanks to the destroyers of troy and mycenæ, and the protective care of temporary oblivion, schliemann is now able to verify tradition and lay before an astonished and delighted world numerous precious relics of heroic ages hitherto remembered only in song. who can estimate the value of these and similar findings to us--the value of the revelations they bring of man's condition in those remote ages? who can say how many or how few the ages will be ere the time comes when the antiquaries of the future will be rejoicing over equally fragmentary vestiges of the doings and possessions of our day? on the other hand, who can estimate the value of the knowledge lost beyond hope of recovery, or the checks to human progress experienced, in the repeated wiping out, so to speak, of the higher races and the civilizations they embodied? and who can say that similar disasters may not come again and again to humanity? suppose a pestilence peculiarly fatal to the white race should fall upon the world to-day, crippling, perhaps exterminating, the now dominant civilized nations; how long would the material elements of our science and art or general culture remain with power to enlighten the barbarous tribes that would inherit the earth? human progress has more than once been set back for centuries by such natural or unnatural causes, leaving the sites of once splendid civilizations to be overrun with barbaric hordes knowing nothing of the better times that went before. suppose, again, that, by one of those geologic changes so numerous in the history of our unstable globe, the existing continents should sink a thousand feet. every center of modern civilization would be submerged. the great social and political organizations of humanity would be broken up, and in the wreck of nations that would ensue very little of the glory and culture of the race could survive. the earth is dotted with vestiges of lost and forgotten empires. can we reasonably assume, in the face of such facts, that the nations of to-day are immortal? the question is: shall we continue to trust to chance, as all other civilizations have, for the preservation of the conquests we have made among the forces and secrets of nature; or shall we do something positive for posterity, and leave the ages to come some certain and abiding legacy of our treasures of art and learning? it may be that human progress will go on and on to the end of time without a break; that in the course of centuries mankind will surpass us in civilization, knowledge and power, as much as we surpass the earliest and rudest men we have yet found traces of: maybe infinitely more. in such a case, what would not the scholars of, say the year a.d., or any other future age, be willing to give for a comprehensive picture of humanity as it exists to-day--for a reasonably complete library of our literature, science, and art? we may safely assume that nothing of the sort will be possible if matters are left to take their natural course. by that time every structure, every machine, every book, every work of art, now in use or stored away in our libraries and galleries of art, will have disappeared, a prey to time, the elements, or the more destructive violence of man. on the other hand, it may be that, through repeated disasters of one sort or another, mankind, three thousand years hence, will have lost all the knowledge men ever possessed, and be slowly struggling upward for the hundredth time from inherited barbarism. in such a case, what enormous benefits might not accrue to man from a fortunate opening up of the wealth of knowledge we possess! in any supposable case between these extremes of progress or degradation, a legacy of art and learning, such as we might easily set apart for remote posterity, would certainly be acceptable, perhaps extremely useful. besides, it might be possible for us to set such a worthy example to those who shall come after us that, come what might, humanity would never be left absolutely void of the means of instruction, nor any worthy human achievement be absolutely lost or forgotten. the experience of these later years has demonstrated the value of such legacies even when unintentional, unselected, and wretchedly fragmentary. it has made clear also how a legacy deliberately made may be indefinitely preserved. roughly outlined, the carrying out of such a truly philanthropic enterprise would involve nothing more difficult than-- _first_. the construction of a practically indestructible treasure chamber in some secure place; and _second_. the preparation of a library well calculated to withstand the corroding tooth of time. two kinds of structures would meet the first demand--massive pyramids of covered earth or of solid masonry, or chambers hewn from the heart of some granitic hill. in low latitudes, where glacial action is not to be feared, the pyramidal form might be preferable: in more northern regions the rock-cut chamber would probably be at once cheaper and more durable. in either case, an elevated site should be chosen as a safeguard against submergence. to secure the permanence of the records would be more difficult. ordinary books and papers would clearly be unsuitable for long keeping; though for comparatively limited periods they might answer if securely packed in airtight waterproof cases. nothing liable to spontaneous decay should be admitted. stereotype plates of metal would be even more open to objection than printed sheets. the noble metals would be too costly, the baser would corrode; and with either the value of the plates as metal would be a standing danger to the deposit. the material basis of the library must be, as nearly as possible, worthless for other uses (to insure them against the natural greed of man), yet such as will hold the records sharply and faithfully under all circumstances. the _terra cotta_ tablets of ancient assyria are instructive in this connection. possibly plates of artificial stone, or sheets of a _papier-maché_-like preparation of asbestos, might be less bulky and equally durable. having determined this point, and dug from the solid rock a chamber for the reception of our legacy, the next step would be the selection of its contents. obviously the books to be preserved should embrace first of all lexicons and grammars of every known form of speech, since it is impossible to tell which of the dialects of to-day will be the parents of the dominant tongue of any distant future time; while we may be practically certain that some one or more of the languages of to-day will furnish a key to any language that men will ever use. next in order would come encyclopædias, the most comprehensive and complete that there might be room for. the sacred books of all nations might come next; then the works of the great poets, historians and novelists; after them, the best obtainable records of art, science, the various industries, and so on, with specimens of the best and most typical of our works of art, manufacture, and the like. the spaces between the various articles should be filled in with some insoluble and neutral substance, to prevent corrosion, or the infiltration of water and consequent damage to the plates. then, the entrance to the chamber being securely sealed, permanent records should be made in many places and in various ways, setting forth the purpose of the deposit, its exact location, and the nature of its contents. among such records not the least valuable would be deeply cut polyglot inscriptions on natural cliffs in different parts of the world, observation having shown that such records may remain to challenge human curiosity for ages after all other records of their time have disappeared. even a single deposit of this sort might prove of enormous value to the race at some critical period of its history. but the probability is that the good work would not end with one deposit. from age to age this and other nations might repeat the experiment, commemorating in this way important epochs in their history. the fashion once set might easily become a permanent feature of all great national celebrations. the cost would be comparatively small: a penny contribution from each of the visitors to the philadelphia exhibition, for example, would have been quite sufficient to provide for a memorial of our first centennial year that would have carried an imperishable picture of the civilization of the day to the end of--our first millennium, at least; and we may safely infer that, whatever may be the condition of the world at that not very remote epoch, a memorial of that sort would be something worth having. as we have intimated, the custom might easily become general, so that in the course of ages the earth would become dotted with such repositories of art and learning. then, come what might to humanity--whatever might be the ups and downs of nations--whatever moral, social, or intellectual advances mankind might make--whatever lapses or disasters might befall them--it could hardly happen that a knowledge of any considerable period of human history, or the advantage of any worthy human achievement, could ever be permanently blotted out and lost. it is true that "posterity" has never done anything of the sort for us. it is true that "posterity" may have no valid claim on us for such a legacy. but we might venture to make "posterity" a present! it would not cost us much, and it might turn out to be immensely valuable and useful to some far future age. * * * * * the lost arts in new york. while the objects of ancient art contained in the castellani collection, recently placed on exhibition in the metropolitan museum of art in this city, are individually of great rarity and archæological value, they derive additional importance from the fact that, viewed conjunctively as a collection, they represent connected histories of two great industrial arts extending over many centuries. both in the work of the goldsmith and of the potter, we are enabled to trace progress from the earliest stages up to a period when the greatest skill was attained, and even subsequently into the era of decadence. in both industries, we find that ancient and mediæval workmen possessed knowledge which we do not possess; and among signor castellani's treasures may be seen handiwork which is the embodiment of two lost arts, the secrets of which the modern world, with all its infinitely superior wisdom, has not yet rediscovered. the productions, in the castellani collection, of precious metal workers dating from prehistoric epochs, the exact dates of which are wholly unknown, and covering the long period ending in the thirteenth century, are represented by the contents of some twenty cases. the first three of these receptacles bear no dates. the ornaments which they contain are of bronze, amber, silver, and glass (the latter having become converted into opalescent silicic acid), and were found in præneste (modern palestrina, italy), and in the territory which was ancient etruria. case no. bears date b.c., and here is a rich treasure of primitive etruscan and phoenician ornaments of gold, adorned with granulated work. signor castellani considers that the workmanship of these objects is so perfect that it is impossible at the present time to explain the process of execution, and very difficult to imitate it. the ornaments are of two kinds--those for ordinary use and those for funereal purposes. the first are massive, and might be worn for years without injury; the others are extremely delicate. all are made of the purest gold, and their decoration evinces the most consummate skill and taste on the part of the artist. there is, for example, a small flask, shaped something like an antique wine jar, and about five inches in height. it is of beaten gold, and is covered with a pattern intended to imitate the similarly shaped designs of variegated glass of the græco-phoenician period. this pattern is entirely produced by minute globules of metal soldered to the surface in tiers of zigzag or vandyke patterns. another specimen is a strip of gold covered with granulated lines and bearing a row of birds in relief. on other ornaments are exquisitely carved heads and flowers, produced apparently by hammering on the reverse of the object, but with a delicacy and precision of touch which is simply marvelous. the closest students of this ancient handiwork are entirely at a loss to understand how the processes of melting, soldering, and wire drawing, which were employed in the art, were performed. modern workmen have failed in their attempts exactly to imitate the old ornaments; and it is certain that the secret of the mechanical agents, whereby it was possible to separate and join pieces of gold hardly perceptible to the naked eye, is lost. signor castellani has taken great pains to solve the problem, reading all the treatises of mediæval goldsmiths, inquiring of all classes of italian jewelers, and experimenting with all kinds of chemicals, in the hope of finding the solder wherewith the minute grains were attached to the surface of the metal. at last he found some of the old processes still employed in a remote district, hidden in the recesses of the apennines, far from the great towns. bringing away a few workmen, he gave them much more instruction, and at last succeeded, not perhaps in equalling, but certainly in rivalling the ancient productions. we question whether the etruscans used fire at all in their soldering, as it would be almost an impossibility to keep the excessively fine tools necessary for the work at a proper heat. mr. joshua rose offers the plausible suggestion that a cold flux was employed, with which the workman followed the lines or dots of his pattern. then the gold granules were possibly sprinkled over the surface, and adhered only to the solder, the superfluous grains being brushed off after the solder had set. there is also a fragment of a finely woven fabric, made of threads of pure gold, found on the body of a woman in a tomb at metapontum. this is without doubt the material to which the psalmist refers in speaking of "the king's daughter" having "clothing of wrought gold;" and in the pentateuch there is reference to gold threads being used upon looms. as we follow the various objects in the twenty cases above mentioned, the decline of the goldworker's art when the use of enamels came into vogue is evidenced. continuing on to later periods, the decadence is more marked under the successors of alexander. in rome, under the emperors, we find gold used as a mere setting for precious stones, and finally the collection terminates with examples of workmanship of the time of charlemagne, when the workmen had lost their cunning, and the noble metal had been altogether debased to secondary uses. the second instance where a lost art is exemplified in signor castellani's collection is in the glazing of the gubbio majolica. we have not space here to review the magnificent series of ancient specimens of pottery in detail; and thus it will suffice to say that, beginning with some of the earliest pieces made by the arabs when they occupied sicily, from the twelfth to the sixteenth century, the collection presents examples of all the finest types of later mediæval art. gubbio, where the peculiar kind of majolica above noted was made, is a small town once in the territory of the dukes of urbino; and in the sixteenth century it became famous for its pottery. this was attributable to the talent of one man, giorgio andreoli, who is reputed to have invented the wonderful luster characteristic of the gubbio ware. the body of majolica is mere common clay; and after the piece is finished on the wheel, it is dried and burnt in a furnace. after the biscuit thus prepared has been dipped in the glaze, the colors are applied on the soft surface of the latter, and the vitrifying process fuses all into a glossy enamel of the color of the pigment. this is still the common practice; and we mention it merely to show that to his pigment and glaze andreoli must have added some third substance, which rendered the enamel capable of reflecting white light as blue, red, green, or yellow light--in other words, of giving the object a luster of a color wholly different from the tints of the pigment. he evidently could produce any desired color at will, and the effects gained are indescribably beautiful. the castellani collection contains superb specimens, which glow like jewels. in one, the scene of the nativity of christ is provided with the figures in low relief, and the exquisite cerulean lustre is imparted to give the effect of moonlight. the rarest pieces are those of which the luster is a delicate green. some blaze with yellow, as if of gold; others exhibit the brilliancy of the ruby; while others resemble the interior of the pearl oyster shell. whether this sheen is produced by polarization of the light in some manner, or whether it is at all analogous to fluorescence, is yet to be decided. the impression of the surface with fine microscopic lines might produce an iridescence, but not separate and clearly defined hues. the ware was intended for ornamental purposes, not for household use; and it was suspended against the rich, dark tapestries of the period with which walls were covered, thus aiding, as it were, in illuminating the apartment with its exquisite radiance. * * * * * the blue glass deception. on september , , general a.j. pleasonton, of philadelphia, pa., obtained a patent for "utilizing the natural light of the sun transmitted through clear glass, and the blue or electric(!) solar rays transmitted through blue, purple, or violet colored glass, or its equivalent, in the propagation and growth of plants and animals." in his specification, of which the above constitutes one claim, he states that he has discovered "special and specific efficacy in the use of this combination of the caloric rays of the sun and the electric blue light in stimulating the glands of the body, the nervous system generally, and the secretive organs of man and animals." he also states that he finds that vegetation is vastly improved by the transmitted blue light. these alleged re-discoveries--for the general only claims to have devised the method of utilizing them--were extensively promulgated through the press early in . subsequently, in , general pleasonton published a book on the subject, the volume being appropriately bound in blue and printed in blue ink. recently public attention has again been called to the subject by a new york daily journal. the peculiar kind of glass in question is known as "pot metal blue," that is, it is stained a bluish violet throughout, and is not clear glass covered with flashings of blue glass. it is used in greenhouses, etc., in connection with clear glass; and in general pleasonton's grapery it appears that only every eighth row of panes was blue. some of the results alleged to have been obtained by exposing animals and plants are as follows: twenty grape vines, in their second year, after being set out under the blue glass, bore , lbs. of splendid fruit. a very weak alderney bull calf was in four months developed into a strong and vigorous bull. heifers when kept under blue glass may safely bear young when months old. a weak child, weighing but ½ lbs. at birth, weighed at the end of four months lbs.--the light in this instance having come through blue curtains. two major-generals with rheumatism were cured in three days. a young lady whose hair had come out regained her tresses; and to these must be added various other cures of severe ailments which we have not space here to recapitulate. the above are the alleged facts; and we propose to consider the supposed discovery in the light of previous investigations. with reference to the theories of electricity, etc., advanced by general pleasonton to account for his phenomena, their absurdity is so complete that we shall waste no time over them. the important question in the matter, and the only one in which the public is interested, is whether or not blue glass is capable of producing all or any of the results imputed to its use. in order to clear the way for the examination of the investigations, the records of which we have carefully collected, let us consider first those which general pleasonton quotes in support of his views. these are ( ) seunebier's researches, which go to show that the blue and violet rays are the most active in determining the decomposition of carbonic acid in plants, and ( ) experiments of dr. morichini, repeated by carpa and ridolfi, proving that violet rays magnetized a small needle. the first statement has been totally disproved. dr. von bezold, in his recent work on color, states that "the chemical processes in plants, as far as they are dependent upon light, are principally caused by the rays of medium and of lower refrangibility. the development of the green color of the chlorophyll, the decomposition of carbonic acid, as well as the formation of starch, etc., in the grains of the chlorophyll, are induced by the red, green, and orange rays." the blue, violet, and ultra violet rays, the same authority goes onto explain, influence "the rapidity of growth, compel the so-called zoöspores to move in certain directions, and alter the positions of leaves, etc." in confirmation of this, we have sach's experiments in , which show that light, transmitted through the yellow solution of potassium chromate, enables green leaves to decompose over per cent. of carbonic acid; while that passed through blue ammonia copper oxide decomposes less than per cent. this proves the superiority of the yellow ray to decompose carbonic acid; and this fact professor j.w. draper discovered a long time ago by the direct use of the spectrum. in still further confirmation, we may cite the investigations of vogel, pfeiffer, selim, and placentim. the last three have conducted researches in full knowledge of those of general pleasonton, and their experiments show that yellow rays are more promotive of the evolution of carbon in animals and its absorption in plants than any others in the spectrum, the violet rays having least power in these respects, with the exception of the red rays in the case of animals. the absorption of carbonic acid by plants, and its evolution by animals, we hardly need add, are prime essentials to the growth and health of each. the notion that light possesses a magnetizing power on steel was upset by niepce de st. victor in . after removing every source of error, he "found it impossible to make one sewing needle, solarized for a very long time under the rays of light concentrated by a strong lens, attract another suspended by a hair, whether the light was white or colored by being made to pass through a violet-colored glass." we can proceed further and even show that violet light is in some respects hurtful to plants. cailletet, for example, says in that "light which was passed through a solution of iodine in carbonic disulphide prevents decomposition altogether." baudrimont says that "no colored light permits vegetables to go through all the phases of their evolutions. violet-colored light is positively injurious to plants; they absolutely require white light." this scientist instituted the most elaborate experiments on the subject, ranging over years, from to ; and the result of all his labor may be summed up in the simple statement that no illumination which human ingenuity can devise is so well adapted for promoting natural processes as the pure white light provided by the creator. so much by way of general denial of the claims of superior efficacy residing in blue light of any kind. now we have yet to examine the peculiar variety of blue light here used. sunlight can, by means of the prism, be split into colored rays, any one of which we may isolate, and so obtain a certain colored light. similarly we may obtain light of a desired color by the use of a colored glass which will stop out the rays not of the hue required. so that we may obtain violet light from the spectrum or by filtering sunlight through violet glass. when, however, dr. von bezold, as above, asserts that the violet rays have such and such an effect, he means the violet of the spectrum, which has its specific duty to perform in the compound light of which it is a necessary portion. but the violet light of the spectrum and filtered violet sunlight are altogether different things. the first, as our valued contributor dr. van der weyde has very clearly pointed out, is "a homogeneous color containing, besides the luminous, the invisible chemical rays without any caloric rays; while the light colored by passing through violet glass is a mixture of blue rays with the red rays at the other end of the spectrum; and it contains a quantity of the chemical rays belonging to the blue and the caloric rays belonging to the red. in fact, violet glass passes a light identical with sunlight, only much reduced in power, containing but a portion of its caloric, chemical, and luminous agency: being simply deprived of its strongest rays." and this the spectroscope has clearly demonstrated. reduced to its simplest terms, then, the necessary conclusion is that the violet glass acts purely as a shade for decreasing the intensity of the solar light. and in the simple fact that it does so serve as a shade lies the sole virtue (if any there be) of the glass. in , dr. daubeny made experiments on the germination of seeds, and in his report is this suggestive sentence: "in a south aspect, indeed, light which had passed through the ammonia sulphate of copper (blue solution), and even darkness itself, seemed more favorable than the whole of the spectrum; but this law did not seem to extend to the case of seeds placed in a northern aspect where the total amount of light was less considerable." in our next issue, we shall review the effects of light and darkness upon the animal organization, and endeavor to account for the curing of diseases and the production of other phenomena which have been erroneously ascribed to the influence of the blue filtered sunlight. * * * * * the wetli mountain railroad and its disastrous trial trip. among the various means proposed of late years for building lines of railroad on the steep slopes of mountains, that of m. wetli, of zurich, switzerland, has attracted considerable attention from european engineers. we have already laid before our readers the system of central toothed rails used on the righi and other mountain roads in europe. in the wetli system, instead of this rail and the pinion on the vehicle engaging it, there is a drum having a helicoidal thread which engages with triangular rails. this drum is attached to the locomotive. the construction will be readily understood from the illustrations given herewith, which we take from _la nature_. the thread on the drum is precisely that which would be formed could a rail similar to one of the central angular rails be wrapped around it; so that it always is in contact with the mid rails, and necessarily prevents any bodily sliding or rolling of the vehicles over the regular track when the drum is held motionless. the v-shaped mid rails are securely fastened to horizontal iron ties, which rest on wooden traverses. the angle of the v is °; the distance between any two traverses is . feet. [illustration: fig. .--the wetli mountain railroad.] the locomotive has three coupled axles, on the mid one of which the drum is attached so as to be raised or lowered to engage the rails at the will of the engineer: it being possible to cause it to act on the rails with a pressure of . tons. the diameter of the drum is . feet. its spiral thread is of steel, very solidly attached, and so made as to grip the rails to a distance of . inch below the level of the track. in order to insure this contact, on the drum axle are two pulleys which run on the exterior road, and of which the diameter determines the depth of the hold of the threads. these pulleys are . inches in diameter, while the driving wheels are very slightly in excess, to provide for the use of tyres. m. wetli's invention, as we have described it, was placed between woedensweil and einsiedlen, switzerland. the difference in altitude between these points is , feet, the distance . miles. the grade is from to per cent over the first six miles of the way, and subsequently decreases to per cent. the wetli railroad was established last october only on the heavy grade, that is, the first six miles. [illustration: fig. .] early in november, trial trips were made which did not prove satisfactory. sometimes the drum thread gripped the triangular rails properly and acted well; again it would wedge itself upon them, and often would simply roll over their tops without engaging at all. after the first trials, during which very many of the rails were broken, m. welti re-adjusted the drum thread. finally, he concluded that he had overcome all difficulties in his apparatus; and accordingly a formal trial was arranged on november . for about four and a half miles of the ascent the drum worked well; and the hoarfrost, with which the rails were thickly covered, showed good contact. afterward it worked irregularly; but the station of schindelleghi, a distance of five miles, was reached without accident, the locomotive dragging a car loaded with tons of rails. it was then attempted to make the descent by the aid of the helicoidal drum; but this jumped the rails, and broke them almost immediately. by the aid of back pressure of steam and brakes, the locomotive was stopped. then, unfortunately, the engine was started again; but hardly had the descent been resumed when it was evident that the drum was not holding, and that the speed was accelerating rapidly. brakes and steam were both found useless, and the engine went tearing over the rails at the rate of a mile a minute. of the fourteen persons in the vehicles, three were thrown out and killed, and the rest were more or less seriously injured. the heavily loaded car left the track, and tore up both central and side rails until its coupling broke. the engineer, with great intrepidity, clung to his engine, coolly giving signals to open switches so that the locomotive might run upon the level track and so expend its momentum; but the engine left the rails at a sharp curve, destroyed the track for about a hundred feet, and finally stopped a mass of ruins, with its brave engineer mortally wounded. whether the wetli system can be made to work as intended by the inventor is regarded as doubtful by the engineers who have examined into the causes of the disaster. * * * * * leghorn hens. if a man keeps leghorns he must have no garden, or he must cover the top of his hen yards. that leghorns are great layers and active hens, there can be no denying, but they are great flyers. we have built our yard a lath and a half high, says the _poultry review_, but what do these saucy things care for that? although they have the whole outside world to range in, yet the garden seems to have a greater attraction than all the rest. the other day we found it necessary to feed a weak chicken in the garden by itself, so that it might be sure of its share. a few minutes afterwards, on looking out of the window, we discovered the weak chicken in the henyard and two leghorn hens finishing up its food. we went out, but the two robbers had fled. going around the corner, we found them rolling in a flower bed. a leghorn will do as much mischief in a garden in five minutes as anything we know of. * * * * * sawdust in rough casting. siehr recommends very highly the use of sawdust in mortar as superior even to hair for the prevention of cracking and subsequent peeling off of rough casting under the action of storms and frost. his own house, exposed to prolonged storms on the seacoast, had patches of mortar to be renewed each spring, and after trying without effect a number of substances to prevent it, he found sawdust perfectly satisfactory. it was first thoroughly dried and sifted through an ordinary grain sieve to remove the larger particles. the mortar was made by mixing part cement, lime, sawdust, and sharp sand, the sawdust being first well mixed dry with the cement and sand. * * * * * suint for waterproofing fabrics.--a german chemist has patented the waterproofing of finely woven fabrics, linen, cotton, etc., by means of suint composition. he adapts his method to securing the suint to wool-washing establishments at a small cost. * * * * * absence of white color in animals. some very curious physiological facts bearing upon the presence or absence of white colors in the higher animals have lately been adduced by dr. ogle. it has been found that a colored or dark pigment in the olfactory region of the nostrils is essential to perfect smell, and this pigment is rarely deficient except when the whole animal is pure white. in these cases the creature is almost without smell or taste. this, dr. ogle believes, explains the curious case of the pigs in virginia adduced by mr. darwin, white pigs being poisoned by a poisonous root which does not affect black pigs. mr. darwin imputed this to a constitutional difference accompanying the dark color, which rendered what was poisonous to the white colored animals quite innocuous to the black. dr. ogle, however, observes that there is no proof that the black pigs eat the root, and he believes the more probable explanation to be that it is distasteful to them, while the white pigs, being deficient in smell and taste, eat it, and are killed. analogous facts occur in several distinct families. white sheep are killed in the tarentino by eating _hypericum criscum_, while black sheep escape; white rhinoceros are said to perish from eating _euphorbia candelabrum_; and white horses are said to suffer from poisonous food where colored ones escape. now it is very improbable that a constitutional immunity from poisoning by so many distinct plants should, in the case of such widely different animals, be always correlated with the same difference of color; but the facts are readily understood if the senses of smell and taste are dependent on the presence of a pigment which is deficient in wholly white animals. the explanation has, however, been carried a step further by experiments showing that the absorption of odors by dead matter, such as clothing, is greatly affected by color, black being the most powerful absorbent, then blue, red, yellow, and lastly white. we have here a physical cause for the sense-inferiority of totally white animals which may account for their rarity in nature. for few, if any, wild animals are wholly white. the head, the face, or at least the muzzle or the nose, are generally black. the ears and eyes are also often black; and there is reason to believe that dark pigment is essential to good hearing, as it certainly is to perfect vision. we can therefore understand why white cats with blue eyes are so often deaf--a peculiarity we notice more readily than their deficiency of smell or taste.--_dr. wallace, british association_, . * * * * * improved trolling hook. mr. henry c. brush, of brush's mills, n.y., has patented through the scientific american patent agency an improved troller, the novel feature in which consists in attaching a float to the shank of the implement under the revolving blade, the object being to keep the troller near the surface of the water, where the fish may see it more readily, and whereby the liability of catching in weeds and logs is obviated. [illustration] a is a float, attached to the shank, _a_, of the troller. b is the spoon, which is swiveled in the usual manner. the device is very simple, and is claimed to prevent all the annoyance arising from the hook catching in sunken obstructions. * * * * * purification of wool and woolen stuff. the process, patented some time ago, for the removal of straw, burrs, etc., from wool, by treatment with sulphuric acid, has been modified by lisc as follows: the stuff is worked for one to two hours in a bath consisting of about gallons sulphuric acid, of ° to °, lb. alum, ½ lb. salt, and grains borax. it is then treated in a centrifugal machine, and afterward subjected to a temperature of ° to °. for removal of the acid it is first washed with pure water for ½ hours, then treated for two hours with fuller's earth, soda, and lime, and finally washed for two hours with fresh water. as sulphuric acid can only be employed with uncolored cloths, or such as have been dyed with indigo, chloride of zinc and chloride of manganese diluted to ° are substituted with fabrics otherwise dyed. * * * * * caffeone. caffeone, the aromatic principle of coffee, may be isolated by distilling or lbs. roasted coffee with water, agitating the aqueous distillate with ether, and afterwards evaporating the ether. it is a brown oil, heavier than water, in which it is only very slightly soluble. an almost imponderable quantity of this essential oil will suffice to aromatize a gallon of water. * * * * * the hemi-plunger. the novel form of vessel, to which the above odd name has been given by its inventor, m. donato tommasi, of paris, france, is a combination of a boat wholly submerged with a raft: a connecting link, to borrow the naturalist's expression, between the submerged torpedo boat and the monitor. the advantages which are expected to be realized from this hybrid craft, the inventor describes as follows: "it is evident that a vessel, plunged several yards below the surface of the sea, is no longer influenced by wind or wave. let the sea be agitated, let there be the most violent tempest, yet the boat which navigates under water will never be wrecked, for the same reason that a fish cannot be drowned. * * * what a beautiful vision, that of traversing the ocean, as a balloon floats through the air, with the same tranquillity, without shocks, without the insupportable rolling and pitching!" etc. the construction of the invention introduced in this glowing manner will be understood from figs. and . a is the plunger cylinder, shown with its side broken away in fig. . in fig. , g is the rudder, h the propeller, and i the tube through which sea water passes to the pump. in fig. , c is the smokestack, m m are compartments in which water may be admitted to increase the weight, and hence the depth of flotation of the plunger, the same being filled or emptied by the pump, p. n is the hold for merchandise, partitioned off from the boiler room as shown. [illustration: fig. .--tommasi's hemi-plunger] [illustration: fig. .--the hemi-plunger, the submerged portion] from the plunger, a, rise two hollow columns, e, to which metallic plates, f, are attached to diminish friction through the water. these support the upper division or platform, b. the second shaft (not lettered), which rises above the platform in fig. , serves to ventilate the plunger. the columns, e, serve as shoots down which merchandise is lowered to the compartments, n; and their upper ends are received in two immense inverted cups attached to the bottom of the part, b. through these cups pass large screws, which confine the columns so that, by removing the connection, the whole submarine apparatus may in case of necessity be freed from the upper works. on each side of the platform, b, which is of elliptical figure, is a large float, seen in fig. , which, by means of racks and gearing, may be raised or lowered at will. usually these floats are carried at a height of a yard above the water. in calm weather, this distance is increased, and in storms it is diminished, the object of the floats being to keep the whole vessel on an even plane, and to prevent too violent oscillations. in order to facilitate navigation in shallow water, the columns, e, may be made telescopic, and operated by hydraulic apparatus, so that they may be shortened at will. any form of engine or propeller may be used. [illustration: fig. .--the hemi-plunger on a voyage] besides the advantage of the vessel being unaffected by waves, since its submerged portion travels far below them, the inventor claims that it will meet less resistance from the water than would a vessel of corresponding volume sailing on the surface. it will make faster progress, because it has no waves to mount and descend; and hence it always travels in a nearly right line. the screw being submerged at a great depth will not tend to turn the vessel from her straight path. the platform being easily detachable may serve as a raft in case of injury to the submarine boat. for fast travel, on lakes, rivers, and shallow water generally, m. tommasi proposes to support his platform on two floats which rest on the surface of the water. no weight, therefore, is thrown on the submarine vessel, which need be constructed with only just enough buoyancy to sustain itself and its engine. in this way, the upper craft has no engine or other load than its cargo; and as it merely rests upon the surface, the inventor thinks that it will skim over the same like an ice boat on ice. for war purposes, the hemi-plunger is especially adapted, because the vulnerable portions, engines, boiler, rudder, etc., are wholly out of the reach of shot. guns are mounted on the platform, which thus becomes a circular or elliptical turret, just above the water when the vessel is in fighting trim. instead of steel armor, m. tommasi has a new invention which he calls hydro-metallic plating. he reserves the details of this for future publication; but generally the armor consists of tubes in which liquid is forced under a pressure equivalent to the resistance, say, of forged steel. he thinks this will oppose shot as effectually as the solid metal, and will have the additional advantage of superior lightness. * * * * * in-soles saturated with salicylic acid have been introduced as a remedy for perspiration of the feet. * * * * * supreme court patent decision. a united states patent was granted may , , to john myers and robert g. eunson for a wood-sawing machine for cutting boards into thin stuff for making picture frame and mirror backs. one of the principal claims was for the employment of two deflecting plates, one on each side of the circular saw, by which both sides of the sawed stuff, as fast as it was cut, was slightly deflected so as not to bind upon the saw. suit was brought by the patentee against dunbar and hopper for infringement, and judgment was given in favor of the patentees, in the united states circuit court, this city, the damages awarded being $ , . the defendants thereupon took an appeal to the supreme court of the united states, which tribunal has reversed the finding of the circuit court and dismissed the complaint. it was held by the supreme court that, inasmuch as the use of a single deflecting plate was old, well known, and in common use, it was simply an exercise of ordinary mechanical skill, and not a patentable invention, to employ a second deflecting plate, although the superiority of the double deflectors, for certain kinds of work, appears to be conceded. * * * * * planing mill machinery. the planing machine, next to the saw, is perhaps the most important agent for the conversion and manipulation of wood in use; and before proceeding to consider it, in its present form, says the author of this article, mr. f.h. morse, in the _northwestern lumberman_, it may not be out of place to notice briefly its origin and history. the first man to employ power in the operation of smoothing the surface of wood was sir samuel bentham, of london, england, and to him belongs the honor of having discovered the principle upon which all planing machines operate. a brief personal notice of this remarkable inventor will serve to show under what circumstances the planing machine originated. his education was secured at the westminster school of london, and, as far as can be ascertained from the meager records of his life that have come down to us, was of the most thorough kind, both classical and scientific, that could be obtained at that time ( ). when his education was finished, he was bound to the master shipwright of the woolwich dockyard, to whom he served an apprenticeship of seven years, acquiring in that time a practical knowledge of the methods of working in both wood and iron then in vogue, and receiving the best scientific instruction that the development of that period afforded. after his term of apprenticeship had expired, he spent about two years in looking up the local peculiarities of other shipyards whose methods of working differed in some respects from those of the woolwich mechanics. in he was ordered by the government to examine into the progress of shipbuilding in northern europe, and in carrying out this commission he repaired to russia, where he invented the first machine for planing wood. its mode of operation, whether reciprocating or rotating, it is impossible to ascertain positively, but the conclusion arrived at, after referring to the specifications of his first patent, which was issued in , is that it worked upon the former principle by means closely analogous to the operation of planing by hand. he seems to have made no use of his venture in russia, though he resided there several years and filled several important positions under the russian government. he returned to his native country in and joined his brother, jeremy bentham, who had at that time just received an appointment from the government to introduce industrial prisons in england. to utilize the unskilled labor of the convicts, the talents of sir samuel were called into use, and he devised a number of new machines, the greater part of which were for working wood. for want of a more suitable place, these machines were constructed at the residence of jeremy bentham, which was thus converted into the first manufactory for woodworking machines. this factory was established in , but was soon found to be too small for the purpose, and another building was occupied. in a lecture before the society of arts, in , professor willis, referring to the shops of the benthams, stated that "there were constructed machines for all general operations in woodwork, including planing, molding, rebating, grooving, mortising, and sawing, both in coarse and fine work, in curved, winding, and transverse directions, and shaping wood in complicated forms; and further, as an example, that all parts of a highly finished window sash are prepared, also all parts of an ornamented carriage wheel were made so that nothing remained to be done by hand but to put the component parts together." in the admiralty consented to the introduction of such of these machines as could be used to advantage in the different dockyards, and they were manufactured under the direction of jeremy bentham, and forwarded from time to time to portsmouth and plymouth, where they were used with good results, performing all that was claimed for them. bentham was joined in by another genius (formerly in the employ of the brothers) by the name of brunel, who had invented several valuable machines, among which was one for shaping block shells, which seems to have had bentham's indorsement. as inspector general, in , sir samuel advised the admiralty to introduce many of his new machines, and also to permit the use of steam engines; accordingly, the dockyards were fitted with engines for sawing, planing, boring, tenoning, mortising, etc. the labor saved by their use can be inferred from the fact that brunel, who had assisted in their construction, received as a premium for his inventions the amount saved in the yards by their use in one year, which reached the respectable sum of $ , . in the same year the government settled with jeremy bentham, after arbitration, and allowed him for machines furnished the yards and prisons, $ , . we learn from testimony given before the arbitrators that "sir samuel bentham prepared a system of machinery for the employment of men without skill, and particularly with a view to utilizing convict labor. in patents were taken out on these inventions to secure their exclusive use for the prisons." the testimony states that no skill was required in the use of these machines; they were introduced into the dockyards and worked by common laborers. it was claimed that nine tenths of the labor was saved by the use of bentham's machines, which proves that they were at least effective, which cannot be said in all cases of those of modern manufacture. the patent of bentham, issued in , is doubtless one of the most remarkable ones ever issued, both for the importance of the inventions it protected and the clearness with which they and the principles on which they operated are described. richards, in referring to that section of this patent which relates to rotary tools for woodcutting, quotes the inventor as saying: "the idea of adapting the rotative motion of a tool with more or less advantage, to give all sorts of substances any shape that may be required, is my own, and, as i believe, entirely new." for those not skilled in nor acquainted with the nature and extent of the various operations in wood conversion which come under the head of shaping with rotary cutters, it will be difficult to convey an idea of the invention here set forth; it includes, indeed, nearly all operations in woodworking, and as an original invention may be said to consist in the discovery of the fact that flat surfaces, or surfaces of any contour, can be properly prepared by the action of rotating tools. it is not to be wondered at that such an operation should not have been sooner discovered, for even at the present time there are few processes in treating material which seem so anomalous as that of planing a flat surface with cutters revolving in a circle of a few inches in diameter. in reference to planing mouldings, it is said: "if the circumference of a circular cutter be formed in the shape of any moulding, and projecting above the bench no more than necessary, the piece being shoved over the cutter will thus be cut to a moulding corresponding to the cutter--that is, the reverse of it, just as a plane iron cuts the reverse. if a plane cutter, such as that above spoken of for cutting a groove in the breadth of a piece, be made so thick, or, as we might be apt to say now, so broad, or so long, as to cover the whole breadth of the piece, it will present the idea of a roller. this i call a cutting roller; it maybe employed in many cases with great advantage to perform the office of a plane." the cutting roller of bentham is the present cutter block of england, or the cutting cylinder of america, and after what has been quoted it may be seen that the idea of rotary planing and moulding machines had been fully grasped by bentham. he goes on as usual to the various conditions which attach to the process of planing, and says further: "if a cutting roller of this sort be placed with its axis horizontal and the bench beneath, it may be made to rise and lower. the bench (machine) may be very readily adjusted, so as to determine the thickness to which a piece will be reduced by being passed under the roller." "to gain time, cutters may be applied to different sides of a piece at once, and such of them as make parallel cuts may be mounted on the same spindle." these extracts would not be out of place in an explanatory lecture or essay on woodcutting at the present day, and cannot help awakening surprise that they should have been written eighty-three years ago, when there had, so far as we know, been no precedents, nor even suggestions from previous practice. the foregoing shows that nearly all the fundamental principles, upon which woodcutting by machinery in its present development depends, were familiar to sir samuel bentham, and though his name has been almost forgotten, it may be safely asserted that he gave to the world more useful inventions than any other man of his age. his work shows throughout a constant method and system of reasoning, which point rather to a life of persistent labor than to one of what would ordinarily be called genius. that latter quality he must certainly have possessed in the highest degree, for without it even his knowledge and experience could not have been equal to the work he accomplished. directed to different ends, his talent and genius would doubtless have secured for him a fame that would live for years, though it does not seem possible that he could have conferred upon the world a greater benefit. * * * * * suicide statistics. a curious and suggestive table of statistics has recently appeared in france, which will doubtless prove of much value in the hands of students of psychology and nervous mental ailments. it relates to suicides; and the conditions, etc., of the people who made away with themselves in in france are taken as the basis of the figures. in that year, , suicides occurred, the largest number ever known in any one year in the country. of these, , , or per cent., were committed by men, , , or per cent., by women. in spite of the careful investigations of the police, the ages of people could be determined. the , others are divided as follows: years, ; between and years, ; between and years, , ; between and years, , ; exceeding the last mentioned age, , . about per cent. of these unfortunates were unmarried, per cent. married, and per cent. widowers. of those which constituted the last two classes, nearly two thirds had children. more than seven tenths of the suicides were effected by strangulation or drowning. the crime was most frequently committed during spring, when per cent. of the whole number destroyed themselves; during other seasons the percentages were: in summer, ; in winter, ; in autumn, . included in the tables are the results of the judicial inquests, showing the professions and callings of the deceased. about per cent. were farmers, per cent. mechanics, per cent. merchants or business men, per cent. members of the liberal professions, per cent. servants, and percent. were destitute of any calling. the table even analyzes, in all but people, the motives which caused the fatal act. thus we are told that killed themselves because of reverses in fortune, through family troubles, through drunkenness, through love, debauchery, etc.; died to avoid physical suffering, to avoid the penalties of capital crimes, for unclassified troubles, and , were clearly shown to have been afflicted with some mental disease. * * * * * communications. * * * * * the frost plant of russia. _to the editor of the scientific american:_ mr. charles williams, of winoa, ohio, has written a letter to that veteran botanist, humphrey marshall, of chester county, pa., on the subject of the abovenamed plant, and my opinion concerning it has been asked for. seeds of this plant were obtained by citizens of boston, who had snow brought from the white mountains and from the coast of labrador, and who stated that they have "now the most unbounded satisfaction and pleasure of announcing that all signs are favorable to the realization of their fondest hopes." this wonderful plant, it seems, was found amid the perpetual snows of the northern boundaries of siberia, in , by count swinoskoff, the eminent russian botanist, and it was by him cultivated at st. petersburgh. the account sent me is very vague, and is evidently not from the pen of a botanist. it is stated that it comes forth on the first day of the year, grows to the height of three feet, and flowers on the third day. it continues in bloom for twenty-four hours, then dissolves itself, being of the finest snow; it has a stalk one inch in diameter, and leaves, three in number, ½ inches wide, covered with infinitesimal frost or snow cones. the flower is of the shape of a star, with petals inches long and ½ inch wide at the broadest part, forming a basketwork of frost. the seeds are like a pin's head. this is about all that can be gleaned from the description, and is by no means satisfactory. allow me to present my humble views of an analogous discovery of frostwork on december , , in a sandy loam in chester county, pa., near the paoli monument. in the _horticultural journal_ of philadelphia, then edited by j. jay smith (new series, volume vii., page , ), an account was published of my observations then. these i have since more fully confirmed. the common dittany (cunila mariana) is frequently met with in december, with the base of the stem surrounded with shellwork of ice, of a pearly whiteness. dr. darlington, in his "flora cestrica" published in , page , under the article cunila, observes: "in the beginning of winter, after a rain, very curious ribbons of ice may be observed, attached to the base of the stems, produced, i presume, by the moisture of the earth rising in the dead stems by capillary attraction, and then being gradually forced out horizontally, through a slit, by the process of freezing. the same phenomenon has been observed in other plants. see observations on _helianthemum_, page ." had the doctor given a more extended investigation, i fancy he would have agreed with me as to the cause. i found hundreds of diversified specimens. i am not aware that it was after a rain, but i took up a number of the plants, and always found a vigorous scaly root bud, undergoing development at this early season under ground, to produce a new stem the following spring. i came to the conclusion that, as the temperature was below freezing and snow was on the ground, the expanding bud, in close proximity to the surface, gave out sufficient caloric or warmth to generate vapor from the moist soil. this vapor rising around the stem of the plant, and attracted by it, becomes congealed into what we term hoar-frost, in numerous forms; some like shellwork, others like tulips, with radiated petals, variously contorted, and often as symmetrical as snowflake crystals. [illustration: root-bud and frost-flower of the cunila mariana (maryland dittany). a, the developing or budding root. b, the old stem of the previous year. c, the congealed vapor or hoarfrost, forming the first flower of various shapes.] that plants in germinating have the power of generating heat was proved by mr. hunter and by lamarck. experiments of hales and du hamel show that vegetation is not wholly suspended, however cold it may be; and that there is a regular and gradual progress till the returning warmth of spring gives a greater degree of velocity to the juices, rendering their development more vigorous and apparent. if the crystallization takes place when the air is calm, the crystals will be regularly formed; otherwise, when windy, i have seen them like a shell within a shell, very thin, of a pearly whiteness. professor tyndall has shown in a very beautiful manner that ice is but an agglomeration of snow crystals: the transparency of the former being due to the expulsion of the air, entrapped in and causing the whiteness and opacity of the latter. there is a formation called the snow plant of california, which arises to some height, and has been compared to various things, a fountain convoluted and enlarged above, a crystallized small bushy shrub, etc.; but on closer inquiry, i have failed as yet to get any definite ideas to its true character. some bulbs in the soil might cause such formations by the congelation of vapor deposited successively upon itself, or the stems of the previous year's growth yet remaining, and thus give them a sheathing of frosting. the shape of a star is common in snow crystals, which we all know assume the most beautiful forms, and which are illustrated in various publications. the eminent botanist count swinoskoff should give us some clue as to the genus or character of the plant, the flower of which, we are told, melted away on being touched, and as to the stamens, the diamond seeds like a pin's head, etc. the whole needs further explanation. i trust those bostonians who are in such hope will edify the public as to the final result of their experiment. what has that veteran in botany, dr. asa gray, to say about it? let some one well qualified tell us more about this frost flower of russia. j. stauffer. lancaster, pa. * * * * * patent matters in washington, d.c. _to the editor of the scientific american:_ from the report of the commissioner of patents, just issued, it appears that its surplus revenue for the past year amounts to over one hundred and five thousand dollars, and that there is nearly a million dollars in the united states treasury to the credit of the patent office; and yet, notwithstanding that this enormous amount is lying idle, our pseudo-economists at the capitol refuse to grant the office sufficient of its own funds to carry on its business promptly. so much is the work behindhand in some of the departments that, as the commissioner states in his report, some of the attorneys who require certified copies of papers have been obliged to employ their own clerks to do office copying, and then had to pay the full legal rate of ten cents per hundred words, the same as though the office had done the work. this style of _economizing_, by making inventors pay two prices for their work, may be "reform" in the eyes of the average democratic congressman; but speaking for myself, as one of those who have had to pay twice, i would prefer to dispense with this style of "retrenchment and reform," and therefore ask you, messrs. editors, in behalf of the inventors of the united states, to so stir up our legislators that they will allow the office sufficient of its own funds to do its work properly, and not delay the work of the inventor--work that he has to pay for in advance--and so prevent the discouragement and trouble which these delays always cause. as the patent office has been doing a good business lately, there appears to be some attempt at rivalry at the capitol, as the following list of applications for extension will show: list of applicants for extensions of patents now before congress. ---- reynolds, power loom brake. strong & ross, scales. wm. & w.h. lewis, photographic plates. t.a. weston, differential pulley. s.s. hartshorn, buckles. h.a. stone, making cheese. n. whitehall, cultivator. j.r. harrington, carpet lining. h.l. emery, cotton gins. j. stainthorp, moulding candles. walter hunt's heirs, paper collars. a.b. wilson, sewing machines. s.a. knox, plows. rollin white, firearms. aikin a. felthousen, sewing machines. h. woodman, stripping cotton cards. l. hall, heel trimmer. j.a. conover, wood splitter. j. dyson, carding engine. g. wellmann, card strippers. e. brady, safety valves. jearum atkins, harvester rakes. john thomas, re-rolling railroad rails. thomas mitchell, hair brushes. stephen hull, harvesters. t.r. crosby, wiring blind slats. g.w. laban, mitre cutting machine. t.a. whitenack, harvesters. j.j. vinton, furnaces. a. fuller, faucets. d. baker, pitcher spouts and lids. g.f. chandler, refining sugar. g.h. nott, boiler furnace. william hall, lightning rods. b.f. rice, paper bag machines. s.d. nelson, shovels. e.t. russell, car springs. hubbell & conant, steam pumps. c.a. chamberlain, shovels. c.a. adams, locks. e.a. leland, paint can. in addition to the above, i find the following names as applicants for extensions, but the inventions covered by the patents sought to be extended is not mentioned: s.s. turner, arculous wyckoff, de witt c. cummings, moses marshall, j.w. fowler, and holloway & graham. many of the applicants have apparently given up their cases for this session, but they may be only lying back to its close in hopes that in the final rush their "little bills" may slip through easily. several bills tinkering at the patent laws are before congress, and one of these (house bill, no. , ) passed the house on the th ult. it has one section that may be made to work great harm to inventors, as it prevents infringers being sued for more than one year's damages previous to notice of infringement being given. by this bill, if it is allowed to become a law, a person will be able to build and use patented machines or processes for years in some out of the way place where the inventor cannot easily find him; and should he be discovered, he can only be sued for one year's damages. there are other sections in this bill which will bear ventilating. another bill, introduced into the senate by mr. paddock, provides that all appeals from the board of appeals shall be direct to the supreme court of the district of columbia, instead of to the commissioner as heretofore; and that the fees shall be the same as now paid to the latter official. mr. sampson has introduced into the house a bill changing section so that it shall read as follows: "sec. . any person who has discovered any new or useful art, machine, manufacture or composition of matter, or any new or useful improvement thereof, not known or used by others in this country, and not patented or described in any printed publication in this or any foreign country, before his invention or discovery thereof, and not in public use or on sale for more than two years prior to his application, unless the same is proved to have been abandoned, may, upon payment of the fees required by law, and other due proceedings had, obtain a patent therefor: _provided, that the manufacture or composition of drugs as a medicine shall not be patentable_." the change is the addition of the words in italics. the smithsonian institute has sent to congress a memorial setting forth that the present institute building is already too small for the vast amount of articles already placed there on exhibition; that at the late centennial exposition the commissioners of various countries presented their entire collection of exhibits to the united states, which had delegated their care to the smithsonian institute, and they had no place for them; that the armory building was being fitted up for the reception of the united states centennial collection, and they therefore asked that a building be erected for the foreign collection, which could be used as a national museum, or otherwise we should have to offend the donors by keeping their valuable gifts stowed away in cellars and other rubbish receptacles. mr. eads, who is now here on the lookout for his pay for his work on the south pass of the mississippi's mouth, has received intelligence from the resident engineer at the jetties that the channel through the shoal at the head of the south pass is now twenty-two feet deep, and that the least width at which twenty feet depth is found is one hundred and ten feet. the principal works to improve this shoal were constructed during the last six months. the low stage and feeble current of the river has delayed their effect until the recent flood from the ohio reached them, and the problem of deepening the shoal has been fully solved by the rapid scouring away of the obstruction. it is stated that the channel is quite straight and is deepening rapidly. the channel through the jetties at the mouth of the pass is twenty-one feet deep. the entrance from the sea through the jetties is one thousand feet wide, and through the works at the head of the pass eight hundred feet. a recent telegram from nevada states that the sutro tunnel (of which i gave you some particulars in one of my letters) has now progressed a total distance of , feet and has fairly entered the mineral belt, and will soon help to increase the already vast products of the comstock lode. while on the subject of mining, i will state that the amount of quicksilver produced in california has increased so immensely during the last two years that it has attracted the attention of all interested in the article throughout the world. the receipts for the year have been , and the exports , flasks. in addition to the receipts there, probably about six thousand flasks were shipped direct from the mines to nevada, thus bringing up the total production to over , flasks, a gain in round numbers of from twelve thousand to fifteen thousand flasks over . the exports in that year were , flasks, or , less than in . occasional. * * * * * tyrian purple ink for marking linen.--von bele gives the following method for preparing an ink for marking linen and cotton: neutralize grains of carbonate of ammonia with pure nitric acid, and triturate to grains of carmine with the solution. mordant the fabric with a mixed solution of acetate of alumina and tin salt, and write upon it, when it is perfectly dry, with the ink. * * * * * new york academy of sciences. on monday evening, january , , a meeting of this academy was held at the school of mines, columbia college, dr. j.s. newberry, president, in the chair. mr. a.a. julian, a.m., read a paper on the preparation of rock and mineral sections for microscopic study. the speaker described in detail the various operations, exhibited the different kinds of apparatus employed, showed the operations, and exhibited the finished sections. in some rocks a thin chip can be broken off, others require to be sawn, and for the latter purpose the diamond saw is best. having obtained the chip, it is first polished on one side, then cemented to a little square of glass, and the other side polished in the same way. the sections must not be too thick, nor too thin; they are usually made from a hundredth to a thousandth of an inch thick. lathes employed in polishing minerals require to be provided with conical spindles, so that the wear, due to grit and emery dust getting on them, may be readily taken up. the grinding wheel may be either horizontal or vertical; the former has the advantage that the mineral can be held in either hand; with the latter only the right hand can be employed, and that in an awkward and tiresome position. mr. julian then referred briefly to the kinds of emery, its preparation by elutriation, etc., and cautioned operators against using rouge or tin putty powder in polishing rock sections, although they may be employed in polishing certain minerals and gems. the object of making the rock sections being to study their constituents and determine what minerals enter into their composition, it is important that no foreign substance, liable to adhere to the specimen and to be mistaken for one of its ingredients, be placed on the section while grinding. lastly, the minerals are mounted on glass, with or without covers, by means of canada balsam. square glasses are to be preferred to the long and narrow strips, usually employed, as less liable to break in the center, and more easily revolved on the stage of a microscope. mr. l.h. landy then exhibited, by means of the gas microscope, several beautiful rock sections, both american and german. the same gentleman also showed the effect of passing polarized light through certain crystal sections, the black cross and rainbow-hued rings revolving like so many wheels as the polarizer was turned. at the conclusion of this brilliant exhibition, dr. p.t. austen made some remarks on laboratory manipulations. the points referred to were the apparently unimportant details which often contribute so much to the ease and pleasure of working. first, the use of square pieces of felt, such as are used under beer glasses in saloons, for setting hot beakers and flasks on to prevent chilling and consequent cracking. second, in crystallizing substances for examination under the microscope; one watch glass is placed upon another with the substance between them, and the upper glass filled with ether, the cold produced by its evaporation hastening the crystallization. third, removing precipitates and solid matter from flasks, by heating to boiling, and inverting in a vessel of water. fourth, crystallization by gradual dilution. fifth, filter paper without ash. in german laboratories it is customary to dissolve out the mineral matter from white filtering paper by washing in dilute hydrochloric and hydrofluoric acids. sixth, the use of infusorial silica for drying purposes. being very porous, it will absorb five times its own volume of water. if a filter paper, holding a wet precipitate, be placed upon a layer of this earth, it will become quite dry in a very short space of time. mr. austen also remarked that substances retain their heat for several days when placed in cork boxes. to keep a substance air-tight, it may be placed in a flask, the neck painted with a solution of india rubber in chloroform, and a plate of glass laid upon it. the solvent quickly evaporates, leaving a delicate film of rubber, which holds the glass tightly in place. the next meeting of the chemical section will be held february ; of the mineralogical section, february . * * * * * annual report of the patent office. the annual report to congress of the commissioner of patents, for the year , has made its appearance. the amount received on applications for patents, reissues, designs, extensions, caveats, disclaimers, appeals, trade marks, labels, copies, etc., was $ , . . the amount paid for salaries was $ , ; other expenses, $ , . total payments, $ , . number of applications for patents during the year , number of patents issued, including reissues and designs , number of applications for extension of patents number of patents extended number of caveats filed during the year , number of patents expired during the year number of patents allowed but not issued for want of final fee , number of applications for registering of trade marks , number of trade marks registered number of applications for registering of labels number of labels registered of the patents granted there were to-- citizens of the united states , subjects of great britain subjects of france subjects of other foreign governments ----- total , the number of applications for patents was a little less than during the previous year. the commissioner suggests that congress should appropriate $ , to promote the printing of the old patents; that additional examiners be employed, and more clerks, for the purpose of expediting the business of the office; that the price of the official gazette be reduced, also the fee for trade mark registration; that the library fund be increased; that more space be provided for models, and for the transaction of business. in respect to the centennial, the value of new improvements, and the service of the patent office in stimulating discovery, the acting commissioner speaks as follows: "the display made at the exposition by the patent office was creditable in every respect, and excited general attention. about , models of inventions, representing the leading branches of the arts and manufactures, were exhibited in suitable cases, and properly labeled, the various publications of the office were displayed, its practice fully explained to all inquirers, and copies of the patent laws and the office regulations and forms freely distributed. the knowledge of our patent system thus imparted to foreigners and all others unable to visit washington has more than repaid the small cost attendant upon the representation. the exhibits were sent from and returned to the office with scarcely any damage being suffered. "but the array of models, etc., made by the patent office at the exposition was not needed to illustrate the value of our patent practice. the wisdom of that system was demonstrated in the most practical and triumphant manner in nearly every branch of that munificent enterprise. not only in the grand display of labor-saving machinery, but in the vast collection of manufactured articles, and even in the department of fine arts, were seen the fruits of that provision in our constitution giving to congress the power 'to promote the progress of science and the useful arts by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries.' "whatever persons may do in a 'perfect condition of society' in sharing, without price, the fruits of their labors with others, it must be apparent to the dullest observer that the wonderful growth of the useful arts in this country is due, thus far, to the protection given by our government to property in inventions--a property as sacred as any other class of property, and whose value is determined by the same general law of supply and demand. "it may be safely said that two thirds of the manufacturing interests of the country are based upon patents, and the welfare of all such interests are intimately connected with the welfare of the patent system. during the past seven years a larger number of applications for patents were filed and patents granted than during the entire seventy-eight preceding years, reaching back to the enactment of the first patent law. the needs of the office have advanced in proportion to this sudden and vast increase of work, but have been but partly supplied. nay, in fact, its already scanty force and accommodations have been actually reduced at a time when most required. if these vast interests, and the future promotion of science and the useful arts are to be encouraged, a liberal recognition must be made of the wants of this office. "the examining corps, the duties in which are most arduous and exacting, comprises gentlemen of legal, as well as scientific, attainments. it should be re-inforced by more of the same character. they should be relieved, by legislation, of continual embarrassment by reason of meager salaries and fears of removal incident to merely political changes. the office would then be spared the continual loss of its most experienced and efficient men." * * * * * the iron trade in england. the british _mercantile gazette_ of january states that the situation and prospects of the iron trade have not materially improved in the month of december, but some week or two must elapse yet before trade returns to its regular channels. in the north of england the tone of the market is tolerably cheerful, and prospects, though still vague, are considered encouraging. makers of pig iron go into the next quarter with a good supply of orders on their books, and merchants and consumers are desirous of buying over the first half of the year. notwithstanding the great depression which has ruled throughout , there is likely to be a greater production of pig iron by several thousand tons than ever there was before, and the total make must considerably exceed two million tons, which is twice the quantity turned out in scotland, though in the latter district a greater number of furnaces have been kept in blast. prices are nominally the same as were quoted last week, but show an upward tendency. the bulk of the mills and forges, foundries, etc., have resumed work, and the finished iron trade is again in full swing. the plate department is well provided with orders, but the rail manufacturers, though rather better off than they were, are still in a poor position. the miscellaneous branches of the iron trade, such as the foundries and tube, wire, and cut-nail manufactories are generally well off for orders, and engineers find plenty to do. the wages agreement in the finished iron trade ends this week, but it is thought that no alteration will be made. in the south staffordshire iron trade, work has been only partially resumed as yet, and many of the mills and forges will not be started until the quarterly meetings, next week. orders have rarely been so scarce as they are at this moment, arrears having been pretty generally cleared off before the holidays, and no new ones coming in. nevertheless, the feeling of the trade is more hopeful than it was a month ago. the number of furnaces in blast in this district is now only out of ; but should the expected improvement in trade arrive with the quarterly meeting, this number will soon be increased. in the finished iron branch, in which quotations for marked iron contain the basis of $ for bars, makers of leading brands of sheets and bars are better off than the manufacturers of cheap iron, who suffer much from competition in the north. some considerable contracts for girders, bridges, gasometers, etc., are under execution at the works devoted to constructive ironwork; but the merchant iron trade, as a whole, is very dull. unmarked iron is weak and variable, and to this circumstance may be attributed the reduction, announced this week, in various descriptions of common iron hardware. * * * * * improved lathe chuck. the annexed engravings represent a new lathe chuck, which may be constructed of any size, which holds tools with great firmness, and which is provided with an improved device for taking up wear and for the separate adjustment of the jaws. the implement is made of the best steel, by special machinery, so that its parts are interchangeable. [illustration: vinton's lathe chuck.] figs. and represent the chuck taken apart so as to exhibit the interior. figs. and are sectional views. a is a collar which encircles the spindle, and has formed on its outer face a bevel gear wheel, b. c, fig. , is the rear portion of the shell of the chuck inclosing the forward part of the collar, a. also on said collar, a, is a washer, d, which rests against the shell, c, and a nut, e, which travels on a thread formed on the collar. as it is necessary, as will be explained further on, to turn the entire shell in order to move the jaws, the use of the nut just described is to jam the part, c, and the enlarged portion of the collar, a, tightly together, and so rigidly hold the jaws in any position in which they may be adjusted. fig. represents the outer face of the chuck with the jaws and their working mechanism. within the chuck, each jaw has attached to it a screw, e. this enters a bevel wheel, f. as the jaws are incapable of any but radial motion, it follows that, when the chuck is rotated bodily and the bevel wheels engage on the motionless gear wheel, b, the effect of the rotation of said bevel wheels is to cause the jaws to travel toward or from the center of the chuck face. and it will be further clear that this motion must be simultaneous in all the jaws. as the outer portion of the chuck is rigidly secured to the shell, c, by screws, of course when that shell is jammed, as already stated, by the nut, e, it becomes impossible to turn the chuck bodily; and hence the bevel wheels cannot be rotated around the main gear wheel, and consequently the position of the jaws cannot be altered. the above comprises the mechanism proper of the device, that is to say, all that is necessary for moving or clamping the jaws. there is, however, another feature of considerable importance yet to be described, and that is the device for taking up any play of the jaws due to wear, and which enables each to be adjusted so that the motion of all may be uniform. by referring to fig. , it will be seen that, above the bevel wheel, there is a projection, into the threaded interior of which, as already explained, the jaw screw enters. surrounding this projection is a sleeve, g, the outer surface of which is threaded to fit a similarly threaded aperture, cut partly in the shell and partly in the face plate. the upper portion of the sleeve is notched to receive a wrench or driver; and beneath the sleeve an armed washer, h, is slipped over the projection. the arms of this washer enter recesses in the face plate. it will be evident that, by turning the sleeve, f, so that the screw works inward, the jaw and all its appendages will be moved bodily in corresponding direction. but its movement is limited by the arms of the washer, g, which, through the narrowness of the recesses, are allowed only just enough play to compensate for slight changes in the jaw. as the above device is applied to every jaw, it follows that any one of them may be nicely adjusted from the outside, so that all are caused to grasp the tool accurately. the spindle, instead of being solid as represented, may be made hollow. patented to j.h. vinton, august , . for further information, address the manufacturer, mr. f. armstrong, bridgeport, conn. * * * * * screw-cutting lathes. [illustration: screw-cutting lathes] an english lathe, now in use at the rogers locomotive works, paterson, n.j., contains several novel features. the ways are flat on the faces, instead of having raised vs; and this is a feature of all english lathes, and of those known in this country as the freeland lathes. a great deal of discussion has at various times taken place as to the relative qualification or merits of these two forms of lathe bed. the advocates of the flat way, with vs at the edges of the way, claim superiority on the score of steadiness, increased wearing surface, and strength; while, on behalf of the raised vs, it is urged that, the vs being true, the saddle is bound to travel true, because there can be no lost motion on the slides; whereas any lost motion, from want of adjustment of the slides in flat ways, is liable to be reproduced twofold in the work, for the reason that / of an inch lateral movement of the slide carriage becomes / of an inch in the diameter of the work. then, again, the most of the wear upon a lathe bed takes place at the part at and near the running center of the lathe, because the saddle is, on account of short jobs, more used in that part than on any other. as a result, when wear has taken place, the saddle, if adjusted to suit the worn part, becomes too tight to travel over the unworn part of the bed; and hence, after the wear has taken place, a proper adjustment of the lathe saddle becomes impossible if the job is a long one. in the case of raised vs, however, the wear simply causes the saddle to fall vertically, so that an amount of wear equal to / of an inch would have the same effect as lowering the tool / inch, its effect upon the work being almost imperceptible by ordinary measurement. on the other hand, however, v lathes are usually made with either a weight or a spring to keep the saddle down; and as a result, when the cutting tool stands far out from the tool post, the saddle is apt to tip, especially in the case of boring with a lathe tool. in some cases, the raised vs are accompanied with gibs to secure the saddle; but in many instances the gibs are given too little wearing surface. in the lathe above referred to, there are three ways in one casting, with the slide angles on the outer edges. there are also three separate and independent tail stocks fitting into the two openings between the ways. the running head has one cone pulley connected by suitable gearing to three face plates. the three centers at the running head are stationary. the slide rest saddle spans the three ways, having a v slide which contains three separate slide rests, all connected by a nut to the feed screw, so that all three are operated by the one screw. in addition to this, the two back slide rests have the nuts so attached that they can be moved by means of a separate screw, the object being to facilitate setting the cuts, since it would be a tedious matter to set all three tools to an equal cut, or to their desired respective cuts, without means of operating two of them independently. to set the cut during screw-cutting operations, the ingenious device shown in our engraving is provided. a represents the cross-feed or slide rest screw, which operates the three slide rests. it is fast to the notched wheel, b, and is operated by it in the usual way. c is a short screw which provides journal bearing for the screw, a, by a plain hole. it is screwed on the outside, and the plate in which it fits acts as its nut. it is fast to the handle, d, and is in fact operated by it. the handle or lever is provided with a catch, e, pivoted in the enclosed box, f, which also contains a means of detaining the catch in the notches of the wheel, or of holding it free from the same when it is placed clear. if, then, the lever, d, be moved back and forth the feed screw, a, and hence the three slide rests, will be operated; while, if the catch be placed in one of the notches on the wheel, b, both the screws, a and c, will act to operate the rests. when, therefore, the operator is cutting screws, he sets the catch, e, into one of the notches so soon as the tools are properly adjusted to the work; and then lifting the catch, e, he turns the wheel, b, so that the catch falls into the next notch, and this puts the cut on. when the tool has taken that cut, and while the latter saddle is traveling back, the catch is placed in the next notch, and so on, the cut for the forward travel always being put on as above while the saddle is traveling back. thus is insured an exactly equable amount of cut on the whole three rests. when the lever, d, is not in use, the catch is removed from the wheel, b, and is allowed to rest against the pins, g or a, provided for that purpose. for piston rods, or for work such as cutting jack screws, this lathe is very useful. it is obviously, however, a special tool. * * * * * natural ornaments in winter. now that the hedges are no longer green, and the trees stand black and bare on the landscape, is the time to seek for endless variety and beauty waiting to be admired in its turn. what miniature fairy glens and grottoes are distributed over the hedge banks of our country lanes! mosses, delicate and beautiful, may be found in the interstices of any old wall, or at the foot of almost any tree or shrub. in the winter time mosses and lichens are found in fruit, and are beautiful objects. a pocket microscope lens is essential for their proper observation; and though the delicate carmine cups of the species known as the cup moss, and the familiar gray and yellow mosaic appearance we see on twigs and branches on our way, are easily recognized, the study of this form of winter vegetation is an inexhaustible one, and is an occupation for a lifetime, if earnestly pursued. we do not however, suggest that every one who endeavors to recognize the different species of moss, lichens, or fungi should necessarily do so through the medium of the microscope; but it will greatly add to the pleasure of making a collection out of doors if there be a good microscope at home, so that when the contents of the basket be turned out, after the winter's walk, there should be interest even in the fragments left, after a little pile of varied bits has been constructed, rivalling the choicest summer bouquet in beauty of form and color. we have seen such a collection formed into a beautiful object by raising a little mound of rough bits of bark in a plate or saucer, and placing on it varieties of fungus of every shade of red, brown, yellow, and gray. they seem to spring forth from a bed of sphagnum or bog moss of brightest emerald green; while a clump of the screw wall moss in fruit, with its curious little box-like capsules, supports a gray or yellow lichen, which has been gently removed from some old wall or tree. a bit of stick or a twig, incrusted with a bright orange-colored lichen, supports a trailing branch of delicate green ivy, the most beautiful and adaptable of all winter foliage. over this little arrangement is placed a bell glass, to preserve it from dust and the effect of a dry atmosphere; and we know how pleasing to the eye is its varied beauty of form and color, lasting thus, a constant source of pleasure, for many a day without renewal.--_chambers' journal_. * * * * * improved harness cockeye. we illustrate herewith a very simple little device for attaching traces to the single tree. it forms a secure fastening which may be instantly attached, and which, by its construction, is prevented from wearing out rapidly. [illustration: figs. and ] fig. shows the cockeye attached to the single tree, and fig. exhibits parts in section, displaying the construction very clearly. the yoke is of the usual pattern. swiveled to it is a long loop, which is chambered out to receive a spiral spring which acts upon a plunger. the latter is provided with a follower having a semicircular notch, which corresponds in form to the inside of the end of the loop. the follower also has guiding lips which extend over the sides of the loop. through the yielding of the spring, the space between the follower and loop adjusts itself to studs or hooks of any size. patented december , , through the scientific american patent agency. for further particulars, address the inventors, messrs. f.w. knapp and c. schallhorn, fiddletown, amador county, cal. * * * * * proposed cremation temple. cremation, in this country at least, is not popular. for a time, it occupied here some public attention, but only in a sensational way; and the sober discussion of the subject, which followed after its novelty had worn off, led to the general opinion that, while every one might be quite willing to see his dead neighbors cremated, no one would acquiesce in the disposal of his friends and relatives in so abnormal a manner. hence, with the single exception of the late revolting exhibition in pennsylvania, which we alluded to at the time, the dead in this country have continued to be deposited in their hallowed resting places, and have not been packed away, in an incinerated state, in labeled urns. in europe, however, cremation still finds many warm adherents; and during last summer a congress of the "friends of cremation" (a society which, we are informed by _engineering_, whence we take the annexed engravings, has branches in various parts of the world), was held in dresden. before this meeting, a large number of designs for cremation and mortuary buildings were brought in competition, and finally the prize was awarded to mr. g. lilienthal, a berlin architect, for the imposing structure illustrated herewith. this will be the grand temple of cremation when it is erected--a proceeding to take place in the dim future: when or where not stated. on each side of a central chapel there is a circular memorial hall; and extending so as to inclose the garden of the establishment, on the sides of the halls are wings containing a large number of niches for the reception of funeral urns. the cremation ceremony is proposed to be as follows: the body, having been brought into the hall, is subjected to the usual medical examination; or when an inquest is necessary, it is removed to offices in another part of the building, where the required investigation can be held. when all is ready, the body, placed on the platform, b, fig. , is raised by a lift into the hall, a, where visitors are gathered, and here the result of the medical examination is declared, and whatever preliminary religious ceremonies that are desired are performed. the body is then transported to the chapel, e, in front of the pulpit, f, where the burial service is performed. the bier is afterward lowered mechanically, and brought to the furnaces, which are arranged in a semicircle and partitioned for the reception of several biers. the ashes are subsequently placed in an urn, on which the name, etc., of the deceased are recorded, and which is set up in a suitable niche. [illustration: fig. .--design for a cremation temple] the building, which we illustrate both in elevation, fig. , and in plan, fig. , is designed to contain , urns, and is adapted for a town of , inhabitants. the architect has certainly exhibited much taste in his design for the building, and has provided every convenience in the internal arrangement for carrying on a large business in the cremation line. [illustration: fig. .--section of a cremation temple.] * * * * * how to rejuvenate an old rose bush. never give up a decaying rose bush till you have tried watering it two or three times a week with soot tea. make the concoction with boiling water, from soot taken from the chimney or stove in which wood is burned. when cold, water the bush with it. when it is used up, pour boiling hot water on the soot a second time. rose bushes treated in this way will often send out thrifty shoots, the leaves will become large and thick, the blossoms will greatly improve in size and be more richly tinted than before.--d.h. jacques. * * * * * a clock collector. one of those odd geniuses, who spend their lives and means in collecting curious and rare articles, lately died. his name was sylvester bonaffon, a retired merchant of philadelphia. his elaborate collections were sold at auction, and their oddity has attracted general attention. his chief mania was for clocks, which literally covered every portion of available space in his apartments, whether they were placed on chairs, tables, shelves, or hung against the wall. some of these timepieces were of unique construction. one clock was made to run for days after one winding; another was set in the dashboard of his carriage, and he used mr. bonaffon also had an especial fondness for electrical apparatus. his windows were provided with ingenious burglar alarms, his rooms with fire alarms, and he ignited his gas always by electricity. his place of business, his stable, the continental hotel where he dined, were all connected with instruments in his room; and he even had perfected arrangements so that he could set at home and send his own messages to california. besides the clocks and electric apparatus, there was an immense collection of _bric-a-brac_ of every conceivable variety, which was sold at the auction--as is usually the case--at prices much below those paid by its late owner. * * * * * fertilizing influence of snow. snow is often called the "poor man's manure;" and if it is true that it has any manurial value, the farmer's prospects for the next season are certainly flattering. the body of snow upon the ground in all the northern and middle states is very great, and millions of acres of land are covered by it as with a blanket of the whitest wool. it is probable that seldom, perhaps never, has so wide an area of our country been covered as during this month of january, . the question whether snow is capable of affording to lands any of the elements of fertility is one often asked; and in reply, the boston _journal of chemistry_ says that it probably is. the atmosphere holds ammonia and some other nitrogenous products, which are without doubt brought to the soil by snowflakes as well as by rain drops. experiments both here and abroad would seem to prove the truth of this conclusion. rains are not only valuable for the moisture which they supply, but for what they bring to us from the atmosphere. during a thunderstorm nitric acid is produced in considerable quantities; and dissolved in the rain drops to a high degree of attenuation, its effects upon soils are highly salutary, as the nitrogen permeates the entire soil. * * * * * action of sea water on lead. the _journal of the chemical society_ says that freshly cut strips of lead were kept in a bottle of sea water for four days, the bottle being frequently shaken. no trace of lead could be detected in the water, but the bright surface of the strips was coated with an insoluble lead compound. hence lead pipes may be used in marine aquaria without any fear of injury to their inhabitants. * * * * * papin's steam engine. by professor charles a. joy. it is a matter of history that, as early as , denis papin, professor of physics and mathematics at the university of marburg, proposed to substitute steam for powder in the engine invented by huyghens, and that in he published a description of several new inventions, in which steam played an important part. the elector carl, of hesse-cassel, was anxious to be free from the annoyances and impositions practised upon his boatmen by the authorities at münden, and he proposed to avoid that city by constructing a canal connecting the weser with the river that flowed through cassel. much of the work was accomplished, and the half finished line of the canal can be traced even at the present day. papin was authorized to build a powerful steam pump by which the supply of water was to be regulated. a working model of this pump was completed; and the elector was on the point of visiting the laboratory to witness its operation, when a fearful explosion frightened the workmen, and afforded an opportunity for enemies to intrigue for the expulsion of papin from the country. the model was preserved for a long time in cassel; but at the time of the french invasion, it disappeared, and no trace of it has since been found. in writing about his inventions, papin says, in : "it would occupy too much space for me to describe in what manner this principle could be applied to removing water from mines, throwing bombs, sailing against the wind, and for many other similar purposes; everyone according to his wants can imagine the constructions that could be made. i cannot, however, refrain from remarking how much preferable this power would be to oars for those whose business calls them to the sea." and further on he says: "the steam cylinders could be employed for a great variety of purposes." one of the cylinders, which was to form a part of the pump, was cast at the foundry in cassel, and after various vicissitudes has finally become the property of the historical museum in that city, where it will be preserved, with jealous care, from any further injury. during the recent exhibition of philosophical instruments in london, this remnant of papin's invention played an important part, it having been generously loaned by the authorities for that occasion. after the flight of papin from germany, the cylinder was used as a receptacle for iron turnings and borings in the royal works; and after the destruction of those works by fire, it came into the possession of henschel, the founder of one of the most extensive locomotive works in germany. this man fully appreciated the value of the historical relic; and when i visited him at the works, twenty-five years ago, he pointed out with pride to me the inscription on its side, "papin's cylinder," and said that he intended to have it placed upon a solid pedestal near the gate. his grandson has since presented it to the city, and its preservation from destruction or sale is now secured. a copy of the drawing made by papin of the pump of which this cylinder was to form a part, and which was published in , has recently appeared in dingler's _journal_, and i send it to you, hoping that you will have it engraved and perpetuated in your valuable paper. it is a peculiar combination of savery's invention and papin's piston engine, suggested for another purpose, and is a decided improvement on huyghens' powder engine. [illustration: papin's steam engine.] a is the boiler for the generation of the steam, provided with a safety valve (an invention of papin). on opening the stopcock, c, the steam passes through b into the cylinder, d, and by its expansion drives the plunger, e, against the water contained in the cylinder, d, which is thus forced into the chamber, f, compressing strongly the air, which in turn expels the water through the pipe, g, to the height desired. k is a funnel for the fresh supply of water, and at i and h are valves opening upwards and downwards. after the condensation of the steam in d, a renewed supply of water, through k, forces the plunger, e, to the top of the cylinder, ready for the next action of steam. the strokes of such a pump could not be frequent, and it would not compare very favorably with the wonderful machinery exhibited in philadelphia last summer; but it contains the germ of the idea, and is worthy of all honor. having often seen it stated that papin had invented a steamboat, i resolved during a recent visit to germany to investigate the matter, and especially to search for the correspondence between papin and leibnitz in the library at hanover. it will be borne in mind that two hundred years ago, on december , , leibnitz was appointed to take charge of the library in hanover, and that he remained in this position until his death in . he bequeathed his manuscripts to the library; and as he had the habit of writing upon all manner of loose scraps of paper, it has cost much labor to assort and classify them. on making my application to the librarian to be permitted to see the correspondence between papin and leibnitz, my request was at once granted; and a table having been assigned me, i was able to examine these precious relics at my leisure. i was also shown a copy of an original treatise on the steam engine by papin, which contained numerous marginal notes by leibnitz. in one place, leibnitz criticized papin's method for condensing steam, and makes a drawing on the margin, showing a piston and valve which he thought would be more practical. it is somewhat remarkable that the germans have not caused a fac-simile of this little volume to be published. after considerable search, i found a copy of the original letter addressed by papin to leibnitz in , asking leibnitz to assist him in obtaining the consent of the hanoverian government to navigate the river weser with a sidewheel steamboat. the letter was dated july , , and contained among other interesting passages the following sentence: "the new invention will enable one or two men to accomplish more effect than several hundred oarsmen." it is evident that leibnitz was deeply impressed by papin's letter, and he supported the simple and reasonable request contained in it by the following petition addressed to the councillors of state. this communication from leibnitz bears two indorsements, one by the clerk of the council, "_pro memoria_ respectfully, in reference to the passage of a ship from the river fulda into the weser;" the other is in the handwriting of leibnitz: "papin's sidewheel ship." this last indorsement is of great value, as indicating the fact that papin proposed to apply side wheels for the propulsion of his new invention. the following is a translation of leibnitz' letter, the original of which i saw in the library: "dionysius papin, councillor and physician to his royal highness the elector of cassel, also professor of mathematics at marburg, is about to dispatch a vessel of singular construction down the river weser to bremen. as he learns that all ships coming from cassel, or any point on the fulda, are not permitted to enter the weser, but are required to unload at münden, and as he anticipates some difficulty, although those vessels have a different object, his own not being intended for freight, he begs most humbly that a gracious order be granted that his ship may be allowed to pass unmolested through the electoral domain, which petition i most humbly support. g.w. leibnitz. "hanover, july , ." this letter was returned to leibnitz with the following indorsement: "the electoral councillors have found serious obstacles in the way of granting the above petition, and, without giving their reasons, have directed me to inform you of their decision, and that in consequence the request is not granted by his electoral highness. h. reiche. "hanover, july , ." this failure of papin's petition was the deathblow to his effort to establish steam navigation. a mob of boatmen, who thought they saw in the embryo ship the ruin of their business, attacked the vessel at night and utterly destroyed it. papin narrowly escaped with his life, and fled to england, where he endured great hardships and poverty, and all traces of him were soon lost, so that it is uncertain in what country he finally died or where he was buried. this remarkable man was driven out of france on account of his protestant faith, and found a refuge in germany; here he was again persecuted on account of the injury that ignorant and jealous people believed his inventions would inflict upon the industries of the country; and when the climax of steam engines for pumping water and propelling ships was reached, the enlightened government of the period "found serious obstacles" in the way of granting him protection, and, without condescending to state what those "objections" were, secretly instigated the mob to make an end of the trouble. it is another instance, unfortunately too often repeated in history, of the mischief men dressed up in a little brief authority can work upon their generation. if papin had been permitted to navigate the weser with his ship, and to carry it to london, as was his intention, it is possible that we should have had steamboats one hundred years earlier than they were given to us by fulton. the plan proposed by papin was highly impracticable; but a knowledge of what savery had done in the way of steam machinery, aided by the shrewd suggestions of leibnitz, combined with the practical assistance of englishmen, would, no doubt, have enabled him to improve upon his invention until it had obtained sufficient credit to be secure against the misfortune of being totally forgotten. after the lapse of years from the date of papin's invention, when the first steamboat was put upon the river rhine, the vessel was fired into by concealed marksmen on shore, and navigation was more dangerous than it is now on the upper waters of the missouri in times of indian hostility. it was only after stationing troops along the banks of the river to protect the boatmen that the government, fortunately more enlightened than in the days of leibnitz, was able to establish steam navigation on a secure footing. i have thought it worth while to make this contribution to the history of steam navigation, particularly as i have been able to authenticate a portion of it by reference to original documents. columbia college, new york city, january, . * * * * * the speaking telegraph. we have heretofore given accounts of the wonderful success of professor bell in transmitting the vibrations of the human voice by electrical means over a telegraph wire. he has lately made improvements in his method of transmission, by which he dispenses with the use of the battery, and substitutes the magneto-electric plan of producing the current. the boston _transcript_ describes a recent experiment with the new apparatus, by which conversation and singing was successfully carried on between boston and malden, a distance of six miles. the telephone, in its present form, consists of a powerful compound permanent magnet, to the poles of which are attached ordinary telegraph coils of insulated wire. in front of the poles, surrounded by these coils of wire, is placed a diaphragm of iron. a mouthpiece to converge the sound upon this diaphragm substantially completes the arrangement. as is well known, the motion of steel or iron in front of the poles of a magnet creates a current of electricity in coils surrounding the poles of the magnet, and the duration of this current of electricity coincides with the duration of the motion of the steel or iron moved or vibrated in the proximity of the magnet. when the human voice causes the diaphragm to vibrate, electrical undulations are induced in the coils environing the magnets, precisely analogous to the undulations of the air produced by that voice. these coils are connected with the line wire, which may be of any length, provided the insulation be good. the undulations which are induced in these coils travel through the line wire, and, passing through the coils of an instrument of precisely similar construction at the distant station, are again resolved into air undulations by the diaphragm of this instrument. the experiments were as follows: telephones having been connected with the private telegraphic line of the boston rubber shoe company, conversation was at once commenced. stationed at the boston end of the wire, professor bell requested mr. watson, who was at the malden end, to speak in loud tones, with a view of enabling the entire company at once to distinguish the sounds. this was so successful that a smile of mingled pleasure and surprise played on the features of those present. that it, however, might not be supposed that loud speaking was essential to intelligibility, mr. bell explained that soft tones could be heard across the wires even more distinctly than loud utterances, even a whisper being audible. in confirmation of this statement, mr. watson commenced speaking in turn with each member of the company; and after the efficiency of this method had been proved to the satisfaction of all, he took up a newspaper and informed the assemblage that gold had closed the previous evening at new york at - / . as there were quite a number of business men present, the effect that this practical demonstration of the value of the telephone produced can scarcely be exaggerated. other passages from the daily journals were then given, and by this time the desire for conversation having become general, mr. watson was plied with questions such as: "is it thawing or freezing at malden? who will be the next president?" etc. it was remarkable that mr. watson was able to distinguish between the voices at the boston end, he calling at least one gentleman by name as soon as the latter commenced speaking. this went on for some time, until a lady at the malden end sent the company an invitation to lunch per telephone, and an appropriate response was made by the same medium. at length the boston company were requested to remain quiet while a lady at the other end conveyed to them the sweet strains of music. the assemblage thereupon listened with rapt attention while a young lady commenced singing "the last rose of summer." the effect was simply charming. the sound of the voice penetrated into the boston end of the telephone with a distinctness equal to that attainable in the more distant parts of a large concert room, and a unanimous vote of thanks was sent by the handy little instrument which had procured for the assemblage so agreeable an hour. * * * * * the superb steam engine built by c.h. brown & co., of fitchburg, mass., which was illustrated and described on page of our current volume, has been purchased by messrs. phineas jones & co., and is being erected in their extensive carriage wheel works at newark, n.j. * * * * * crossing a river on a wire. a reporter of the new york sun wanted to realize the sensation of being suspended on a wire feet from the surface of the earth. he applied to the engineer of the brooklyn bridge for permission to cross the east river on a wire, three quarters of an inch in diameter, which hangs between the two towers. he was refused permission; but he finally saw the president of the company, who granted his request. arriving at the appointed time, the engineer, mr. farrington, said: "well, sir; whenever you're ready, i am." "all ready, said i, as bold as brass outside, and as nervous as the endorian witch on the inside. he walked on and i followed, when, horror of horrors--capital h's--to both horrors--instead of leading me to the 'cradle,' which i called a raft, he took me to a little square board held up by two crossed iron arms, called a 'buggy.' it was about three feet square, and depended from the 'traveler,' a three quarter inch wire which crosses the river, and is run from tower to tower over apparatus, by means of a stationary engine. it was too late to back out, but i didn't feel exactly prepared to plunge in. he did. "he jumped in, and the little buggy swung from side to side, precisely as a swing does when you jump on the board and try to steady it by the ropes. i looked at him, at the scale--that's it; it's exactly like a pair of scales, with one scale--at the deep depths below us, and at myself. i imagined the ticklish thrill which would permeate my body when we started. i fancied the glories of the prospective perspective before me. "'come, hurry up, please,' interrupted farrington, and with resignation i hurried down. he stood up. i crouched down. perhaps you think you'd have stood up as he did. you're mistaken. i crouched down and held on tight. make no mistake. i held on tight and waited for my thrill. it didn't come. then i stood up, and farrington gave the word 'go.' 'wouldn't you better take a rope along?' said one of the men. 'yes, i think i would.' what did he want of a rope? he feared i would be nervous. he meant to grapple me in the middle of the river, and tie me in. i knew it. i felt it. but i didn't say a word. "with a gentle jerk we started--slow, slow, very slow. farrington stood in front and watched the wire. i stood behind and watched myself. i felt nothing. i was'n't exhilarated. i was'n't scared. i was'n't even timid. i can't look from the top of a house without desiring to jump off, but i looked down from the buggy and hadn't the least desire to jump. farrington says: 'it's because it's so high up.' well, we went on without any special sensation till the buggy struck against a stay rope which reaches from one of the cables to the tower. in the effort to free the buggy, mr. farrington gave a push which swung us out some little distance and back again, at which a little piece of indigestion seemed to be monarch of my interior, and for a moment i was on the verge of a sensation. having passed the middle, the ascent was more labored. i waved my handkerchief to the people on the ferryboats. i looked out toward the sea. i looked up at the heavens. i even looked toward harlem, but, like the buyer in the bible, i said: 'it is naught, it is naught.' "in about eight minutes we touched the new york side--all but ten feet. the red flag waved for the engine to stop. there we hung in mid-air feet above the level, swinging to and fro like a drunken buggy, at an angle of forty degrees, and quite uneasy. the rope which was to haul us on was fastened to the iron--blest be the tie that binds--and with a few hearty pulls we were brought so near the new york tower that without difficulty we clambered up. i had made the trip, but i had not felt a feel. from the top of the new york tower i saw much, but the chief point of interest was the innumerable jets of steam which flourish in the air, and fantastically curl off into space. "again the steeples, the tower, and the long, narrow, dirty river filled the prospect, and the bright sun of a charming day lightened up the western sky that was all, except to say 'thanks and good-bye,' and descend the stairs. there were of them stairs, and before i reached the bottom i was dizzy, faint, seasick, and filled with a decoction of tickle, so that i had to shut my eyes and rest from my labors. "thus ends the trip which filled my anticipatory imagination as the waters fill the sea, but which resolved itself in realization to a simple, childlike faith in the fixtures on the wire, and in the skill and competence of the man who guided them. monsieur x." * * * * * blue glass science. there is nothing more reassuring in these days, when new "isms" of the scientists are slowly sapping the foundations of cherished beliefs, than to remember that, after all, the much vaunted dicta of nature are yet opposable by the sound operations of honest common sense. see for example how one of our evening dailies, tossing the dogmas of so-called science contemptuously aside, evolves such profoundly original thoughts as these, to explain the lucid blue glass theory of general pleasonton: "the blue glass presents an obstruction to the sun's rays which can only be penetrated by one of the seven primary rays--the blue ray; the remaining six rays, travelling with the velocity of , miles a second, falling upon the blue glass, are suddenly arrested; the impact evolves upon the surface of the glass friction, heat, electricity and magnetism; the heat expands the molecules of the glass, and a current of electricity and magnetism passes through it into the room; this current, falling upon animal or vegetable life within, stimulates it to unusual vigor. certainly the results achieved, and abundantly certified to, are marvellous, and sufficient to provoke further experiments and inquiry." prior to these splendid original discoveries of our contemporary, we ignorantly believed that blue glass only partially sifted out the orange and yellow rays from the spectrum, and that with this exception, it acted merely as a screen to diminish the intensity of all the rays. we also supposed that there was a sharp distinction to be drawn between sunlight after passing through blue glass and the blue spectral ray: that in one case all the colored rays were more or less present, and that in the other but one was. but think of the utter dismay of such pretenders as helmholtz, tyndall, and henry when they learn that the undulatory theory of light with which they have so long taxed our credulity is overthrown--that of the seven primary rays, six bounce off from blue glass and distribute themselves over the adjoining neighborhood. that the glass is heated by the impact; and as the sun persistently emits more rays, there are more impacts and more heat. the glass gets hotter and hotter; but--mark the scientific acumen here--just as we are wondering whether it will reach the melting point, the pores open. it is the turkish bath of nature. electricity and magnetism, no longer shut out, rush in between the separate molecules. hand in hand, these great curative powers seek a proper subject. they meet (we learn from a report, also in our contemporary, of pleasonton's latest triumph) a pig or a young lady whose hair has come out--a heifer, a rooster, or a rheumatic child. forthwith the pig fattens, hair equal to that produced by the finest _tricopherus_ pervades the female scalp, and "unusual vigor" and general happiness prevail. such is the boon which pleasonton bestows on humanity, as elucidated by the original genius of our contemporary. * * * * * infectious disease propagation. in view of the alarming prevalence of scarlet fever in many parts of the country, the following hints by the _british medical journal_ are wholesome warnings: "there are three common ways by means of which infectious diseases may be very widely spread. it is a very usual practice for parents to take children suffering from scarlet fever, measles, etc., to a public dispensary, in order to obtain advice and medicines. it is little less than crime to expose, in the streets of a town and in the crowded waiting room of a dispensary, children afflicted with such complaints. again, persons who are recovering from infectious disorders borrow books out of the lending departments of public libraries; these books, on their reissue to fresh borrowers, are sources of very great danger. in all libraries, notices should be posted up informing borrowers that no books will be lent out to persons who are suffering from diseases of an infectious character; and that any person so suffering will be prosecuted if he borrow during the time of his illness. lastly, disease is spread by tract distributors. it is the habit for such well meaning people to call at a house where a person is ill and to leave him a tract. in a week or so the tract is called for again, another left in its place, and the old one is left with another person. it needs not much imagination to know with what result to health such a practice will lead if the first person be in scarlet fever or smallpox." dr. hutton offers "a warning on the reckless manner in which parents allow their healthy children to run into the houses of acquaintances who have members of their families suffering from scarlatina, etc., and states that he has seen the infection thus carried from the patient, and several families attacked." * * * * * toughened glass making in brooklyn. a _world_ reporter has lately visited the works in brooklyn where the manufacture of the la bastie toughened glass is now in active progress. the manufacturer states that, in june last, his factory was destroyed by fire, and the introduction of the glass into our markets has for that reason been delayed. only one kind of goods, lamp chimneys, are now made, and the process is as follows: a workman, having in his hand a pole about eight feet long, with a knob on the end of the size of a lamp burner, fits a chimney on the knob and plunges it into the flame of a furnace. he with-draws it twice or thrice that it may not heat too quickly, turning the pole rapidly the while, and when the glass reaches a red heat quickly shoots it into one of a dozen small baths fixed on a revolving table, and seizes another chimney. a boy keeps the revolving table always in position, and as the chimneys come around to him, having been the proper time in the bath, he takes them out to be dried, sorted, cleaned, and packed. the bath has to be of just the right temperature, as, if it be too hot or too cold, the chimneys are liable to explode. in either case the process of annealing is imperfect. by working the tables at a certain rate, the baths are kept at the right temperature by the immersion of the red hot glass. oil or tallow is used in the bath. any greasy substance will do, though tallow has proved most satisfactory. m. de la chapelle, the manufacturer, states that he has already sold $ , worth of the chimneys. the toughened chimneys are about per cent dearer than those of ordinary glass. the factory is in delavan street, brooklyn, n.y. * * * * * alexander bain, electrician. this ingenious man, whose inventions in connection with the electric telegraph entitle his name to be held in grateful remembrance, died in january last at the new home for incurables at broomhill, kirkintilloch, near glasgow, scotland, and on saturday his remains were interred in the burying ground in the neighborhood of that town known as the old aisle cemetery. mr. bain, who was about sixty-six years of age, was a native of thurso. he was the inventor of the electro-chemical printing telegraph, the electro-magnetic clock, and of perforated paper for automatic transmission of messages, and was author of a number of books and pamphlets relating to these subjects. sir william thomson, in his address to the mathematical section of the british association at its meeting in glasgow last year, said: "in the united states telegraphic department of the great exhibition at philadelphia, i saw edison's automatic telegraph delivering , words in seconds. this was done by the long neglected electro-chemical method of bain, long ago condemned in england to the helot work of recording from a relay, and turned adrift as needlessly delicate for that." mr. bain was stricken by paralysis, and suffered from complete loss of power in the lower limbs. for some time he had received a pension from the government, obtained for him, we believe, through the instrumentality of sir william thomson. mr. bain was a widower, and has left a son and daughter, the former of whom is in america, and the latter at present on the continent. photographs of him by mayall were recently presented to the society of telegraph engineers and the american society of telegraphers at philadelphia. --_the engineer._ * * * * * self-reliance necessary to success. self-reliance, conjoined with promptitude in the execution of our undertakings, is indispensable to success. and yet multitudes live a life of vacillation and consequent failure, because they remain undetermined what to do, or, having decided that, have no confidence in themselves. such persons need to be assured; but this assurance can be obtained in no other way than by their own successes in whatever they may attempt for themselves. if they lean upon others, they not only become dissatisfied with what they achieve, but the success of one achievement, in which they are entitled to but partial credit, is no guaranty to them that, unaided, they will not fail in their very next experiment. for want of self-reliance and decision of character, thousands are submerged in their first essays to make the voyage of life. disappointed and chagrined at this, they underestimate their own capacities, and thenceforward, relying on others, they take and keep a subordinate position, from which they rise, when they rise at all, with the utmost difficulty. when a young man attains his majority, it is better for him, as a general rule, to take some independent position of his own, even though the present remuneration be less than he would obtain in the service of others. when at work for himself, in a business which requires and demands foresight, economy, and industry, he will naturally develop the strong points of his character, and become self-reliant. a glance at the business men of any community will show who have and who have not improved the opportunities of their earlier years. the former transact their business with ease, promptitude, and profit. they rely upon themselves, and execute what they have to do with energy and dispatch. but those who shirked everything in their youth are compelled to rely on their clerks and salesmen for advice, and are never ready to act when occasions of profit arise. many parents commit a lamentable error in this respect. they lead their children to believe that they can do nothing without the constant assistance of their superiors, and after awhile the child becomes impressed with that idea. fortunate will it be for him when he emerges from the parental roof, if he can at once acquire the self-reliance which has been kept down at home--otherwise he must necessarily fail in whatever independent enterprise he undertakes; and in such a case, while the misfortune is his own, the fault lies at the door of misjudging parents rather than at his own. * * * * * something to do. it is an old trick of despots, and a good one, to employ their subjects. why? to keep them out of mischief, employed men are most contented. there is no conspiracy. men do not sit down and coolly proceed to concoct iniquity so long as there is plenty of pleasant and profitable employment for body and mind. work drives off discontent, provided there is compensation in proportion to the amount of labor performed. there must be a stimulant. god never intended a man should sweat without eating of the fruits of his labor--reaping a reward--more than he intended the idle man should revel in plenty and grow gouty on luxuries. industry is a great peacemaker--a mind-your-own-business citizen. something to do renders the despairing good-natured and hopeful--stops the cry of the hungry, and promotes all virtue. the best men are the most industrious; the most wealthy work the hardest. they always find something to do. do you ever wonder that men of wealth do not "retire" and enjoy their substance? we know some young men look forward with anticipation to the time of "retiring." it is doubtful if a man should ever retire from business as long as he lives. we think we know men who, were they to abandon business, would be ruined, not pecuniarily, but mentally--their lives would be shortened. god never intended man's mind should become dormant. it is governed by fixed laws. those laws are imperative in their exactions. something to do! "oh, if i had something to do!" there are young men who sigh for it, yet one thing they can do--that is, seek for a job. once found, provided it is an honest one, do not hesitate to perform it, even if it does not pay as well as you expected. * * * * * moneyed men. the cleveland _herald_ said, twenty years ago, during a stringency of the times, that moneyed men are the veriest cravens on earth: so timid, that on the least alarm they pull their heads, turtle-like, within their shells, and, snugly housed, hug their glittering treasure until all fear is removed. the consequence is that a few days' disturbance of the monetary atmosphere brings on a perfect dearth of not only the precious metals, but even of paper money, their representative. moneyed men never adopt the tactics of mutual support; hence, as soon as a shot is fired into the flock, they scatter, each looking out for himself, each distrustful of the other, and each recognizing only the great law of selfishness, which is to take care of number one. courage has saved many an army, even when ammunition was low; and many a foe has been scattered by one yell of defiance when there was not a cartridge left. * * * * * new books and publications. archology, or the science of government. by s.v. blakeslee. price $ . . new york and san francisco: a. roman & co. this book is a very metaphysical treatise on theories of government and the duties of citizens to the law, each other, and themselves. theoretical politics are little in favor with thinking men of this day; and the social difficulties of our age will have to be solved by practical wisdom founded on experience. the people that knows that a certain course of legislation has destroyed an empire, and that a contrary policy has developed one, will care little as to whether or not "the will controls the feelings by mediate and indirect force." we are unable to find in this book any attempt to apply the finely worded theories stated to practical use and popular instruction in political science. graphical analysis of roof trusses, for the use of engineers, architects, and builders. by charles e. greene, a.m., professor of civil engineering in the university of michigan. chicago, ill: george h. frost. the author of this work truly says that any designer who fairly tries the graphical method will be pleased with the simplicity and directness of the analysis, even for apparently complex forms. the hindrance to the general use of the method is the want of knowledge of the higher mathematics, which are largely used in most treatises on the subject. professor greene has avoided this stumbling block, and given us a treatise which may be understood and appreciated by any one of common school education. we therefore give his work a hearty commendation, and we hope that every carpenter and builder may be induced to analyze the stresses which affect the different parts of structures, which he can readily do by carefully reading this volume. the hub: a journal devoted to the carriage building trades. published monthly. subscription price, $ . a year. new york city: the hub publishing company, pearl street. this journal is widely known for its accurate and extended information as to carriage building, trimming, lining, painting, etc.; and since its first issue it has maintained its reputation, and given the public an immense amount of instruction in a spirited and practical manner. the illustrations and typography are excellent, and every number shows how extended an area it serves as an authority on the important industry to which it is devoted. assignats and mandats: the money and the finances of the french revolution of . by stephen d. dillaye. price, free by mail, cents. philadelphia, pa.: henry carey baird & co., walnut street. mr. dillaye differs with the hon. a.d. white, president of cornell university, as to the relative merits of money and promises to pay money; and he begins with the assertion that the president's "object is to depreciate american credit, stability, and honor." further perusal, to ascertain the meaning of this attack on a patriotic and useful member of society, shows us what mr. dillaye thinks he means. he talks of credit being the vital element of national power; and from this he argues that the more "credit" a nation has--that is, the deeper it is in debt--the more powerful it becomes. in short, he confuses credit as opposed to discredit with credit as opposed to cash--a grievous blunder, surely. a nation's credit is like a merchant's; it becomes greater only as his debts become smaller; and people trust a government for the same reason as they trust an individual, mainly because every previous obligation has been honorably observed. it is gratifying to know that persons of mr. dillaye's way of thinking are few and unimportant, and their number is diminishing daily. croton water supply for the city of new york: an address by george b. butler to the new york municipal society. new york city: published by order of the society, madison avenue. a review of the whole subject of our water supply, its sources and the area they drain, the geographical features of the district, and the works erected by the city. mr. butler maintains that the croton valley, with proper storage reservoirs, can abundantly supply the whole city; and that no new aqueduct need be constructed in the present condition of the public debt. eine kurze allgemeine einleitung zu den aromatischen nitroverbindungen. von peter townsend austen. leipzig, germany: winter, publisher. we are glad to see that an american is able to publish a very useful chemical treatise in germany, the great head center of chemistry. dr. austen, one of our most distinguished young chemists in the field of original research, has produced a work which bears the marks of much patient thought and study. the book is dedicated to the renowned german chemist, professor a.w. hofmann. our young folks' magazine: a monthly journal of instruction and amusement. subscription price, $ . a year. boston, mass.: post office box . a readable little periodical, well calculated to amuse the little ones for whom it is intended. glass for the studio and dark room. by thomas gaffield. philadelphia, pa.: benerman & wilson. there is much useful information in this little pamphlet, and photographers especially should read it. the matter first appeared in the philadelphia _photographer_. * * * * * recent american and foreign patents * * * * * new agricultural inventions. improved gang plow. ezra peak, montana, kan.--this invention is so constructed that it may be easily raised from and lowered to the ground, and adjusted to work at any desired depth in the ground. it is claimed to be of lighter draft than plows constructed in the usual way, also to be simple in construction and inexpensive in manufacture. the wheels, the faces of which are notched to give them a slight up-and-down movement as they are drawn forward, slightly jar the plows, and thus cause them to be easier drawn than when smooth wheels are used. the shaft can be provided with a ratchet wheel and pawl to hold it in any position into which it may be turned; and to it is attached a rope or chain, the other end of which, is attached to the forward end of the frame, so that by turning the shaft the plows may be raised from, lowered to, and adjusted to work at any desired depth in the ground. improved plow. james willis hendley, cedar hill, n.c., assignor to david n. bennett and samuel t. wright, of same place.--the objects here are simplicity and cheapness of construction, and such arrangement of parts as will prevent the plow becoming clogged with weeds, etc. the mold-board is welded to the land side, or cast in one piece with it, so that no brace or other connection is required between the mold-board and standard; secondly, the curved beam is attached to the heel of the land-side and supported by a brace, which is bolted to the middle portion of the latter, and arranged in such relation to the mold-board that a space is left between them, into which the trash will fall, and thus be drawn into the furrow and covered. improved grain drill. george w. osborn, parkville, mich.--this is an improved attachment for seed drills, for gaging the depth at which the grain shall be deposited in the earth. it consists in an adjustable spring gage bar attached to the shank of each drill tooth, whereby the teeth may be made to enter the ground a greater or less depth. it is claimed to ensure the planting of seeds at equal depth in hard or soft ground, and to diminish the draft. improved horse hay rake. joseph b. wakeman and john l. wager, deposit, n.y.--the construction of this implement is such that a large space is afforded beneath the rake head for the collection of hay. the pivots of said rake head back are also brought back, so that the teeth may be readily raised to discharge the collected hay. by an ingenious lever arrangement the driver is enabled to hold the rake to its work by the pressure of his foot, and also readily to discharge the hay gathered. improved bee hive. george w. akins, bridgeton, pa.--in this hive, holes are bored in the sides of the compartment for ventilation, and windows are flared for the purpose of inspecting the inside of the hive. a frame is used whenever it is desired to have the honeycomb of any particular shape. it consists of a form of tin or other suitable maternal, placed on a frame or slide, and having the shape required in the comb. bees will build inside of the form, leaving about one fourth inch space between the form and the comb. the tin sheet receives a portion of the refuse matter, and can be readily taken out and cleaned. on the st of may the bees are driven out into another hive and the frames examined. three frames are taken out and set in a new box, and three empty frames are put in their place. the old queen must be put with the new colony, and half of the bees must be put in each box and shut up, and put on a stand. the hives are to be opened the next morning. at the next natural swarming time the swarms can be again divided. the hive cannot freeze, and it is proof against mice. improved plow stock. robert weber, new ulm, texas.--in this invention, by loosening a nut, the point of draft attachment may be raised and lowered to cause the plow to work deeper or shallower in the ground, or turned to one or the other side, to cause the plow to take or leave land, and may be secured in place when adjusted by again tightening the nut. improved combined hay tedder and side rake. john huber and henry snell, girard, ill.--this machine may be used simply for stirring up and turning the hay, or for turning the hay and gathering it into windrows. the shaft of a reel revolves in bearings attached to the side bars of the frame near their rear ends. to the bars of the reel are attached spring teeth, which, as the machine is drawn forward, take hold of the hay, carry it up and over the reel, and drop it to the ground in the rear of the machine. a carrier takes the hay from the teeth, when it has been brought to the top of the reel, carries it over the shaft, and discharges it into a trough, down which it slides, and is deposited in a windrow along one side of the path of the machine. improved grubbing machine. ira burley, redwing, minn.--this invention consists in the combination of wheels and axle, tongue, adjusting bar, adjustable brace, uprights, cross bar, two ropes, and four pulley blocks with each other. to the forward end of the tongue is attached a loop or clevis, to receive an iron pin, to be driven into the ground to keep the machine from moving about while being used. to the pulley block is swiveled a hook, to be hooked into a loop, attached to the forward end of a lever. the rear end of the lever passes through a slot in the upper end of a fulcrum post, and has a notch formed in its lower side to receive a bolt or pin, attached to said post to serve as a fulcrum to said lever. several notches are formed in the lever to receive the fulcrum bolt, to enable the position of the fulcrum post to be adjusted to regulate the leverage, and as circumstances may require. to the lever is attached a strong clevis, to receive the hook of the chain, that is secured to the stump to be pulled. improved seed planter. daniel j. davis, red boiling springs, tenn.--in this invention two wheels revolve upon the journals of the axle. upon the end parts of the axle are attached the rear ends of side bars, the forward ends of which are bolted to the outer sides of the forward ends of the plow beams. the forward ends of the beams are bolted to the ends of the front bar, to the center of which is secured the forward end of the central bar. to the beams are attached the plows for opening furrows to receive the seed as it passes from the conductor spouts. the lower ends of the spouts or tubes pass in through the sides of the plows, so as to conduct the seed into the bottom of the furrows before they have been partially filled by the falling in of the soil. the dropping plate is concaved around its dropping holes, and is provided with a plate that may be adjusted to cover one set of dropping holes to drop the hills twice as far apart as when both sets of holes operate. improved animal trap. thomas n. hughes, muddy creek, tenn.--this trap is for animals of all kinds, as rats, mice, and larger animals, as foxes, minks, coons, etc., that are allured by bait, and is automatically set again by the animal caught, to be ready for the next animal attracted by the bait. it is divided by a longitudinal partition into two main sections, in which the working parts are disposed. the entrance at the end of one section has a drop door, which is arranged back of the same, resting, when closed, on side strips in inclined position, and being supported on an upright arm, of a centrally pivoted treadle door, at the bottom of the trap, when the trap is set. the treadle door is only required to swing sufficiently on its pivots to release the drop door from the arm, suitable seats at the under side of the trap, at both sides of the treadle door, preventing the door from swinging farther than necessary. the bait is placed, in a grated receptacle, near the treadle door, and entices the animal to pass in, so as to close the drop door when it arrives at the part of the treadle door near the bait. the back end of this section is perforated or grated to admit light, which attracts the frightened animal and induces him to pass toward the light. the top part of the trap may be grated to admit air, and the glass door at the end made to slide, to admit the taking out of the animals for killing them. * * * * * new miscellaneous inventions. apparatus for the hydration of chlorine gas. william maynard, new york city.--this invention relates to an improved construction of apparatus for the hydration of gases, and more particularly chlorine gas for the manufacture of chlorine water for use in the industrial arts of bleaching, etc. it consists mainly in a case having an inlet for the water above, an inlet for the gas below, and provided with an intermediate water percolating medium; combined with a reservoir located below the level of the case and having a water-sealed communication therewith, which reservoir receives the hydrated gases, and which water seal prevents the heavy gas in the case from passing out through the bottom inlet. the case for the percolation of water and the absorption of the gas is made of conical shape, with the largest diameter at the bottom, to produce the greatest absorption of the heavy gas when first admitted; while horizontal partitions, or shelves, in said case are provided with upwardly projecting tubes which hold a permanent surface of water on the said partition or shelves. the tubes permit, by their peculiar shape, the water to pass down on one side and the gas up on the opposite side of said tube, while their alternating arrangement in the alternating shelves gives a zigzag and long continued passage to the gas and water in moving in opposite directions through the case. improved process of preparing gas fuel. martin n. diall, terre haute, ind.--this inventor saturates wood by immersing it in any hydrocarbon oil for from six to twelve hours, as required by the nature of the wood, so that it may take up the necessary quantity of oil for the required strength of gas. the wood is then immersed in a bath of water, for taking up a quantity of water outside the oil, and is then charged in the retorts, the same as coal, and distilled in the same way. by this process the inventor claims that he produces fixed gas equal to coal gas, much faster, and with less expense, the wood and water furnishing the hydrogen, and the oil furnishing the carbon. improved fishing line leader. welmer t. jahne and anthony moors, jersey city, n.j.--this consists of a leader made of spring wire, bent into v form, provided with a swivel and eye at its middle part, and with eyes or loops at its ends to receive the line and snells. by this construction the snells and hooks will be kept apart however the line maybe thrown, and however they and the leader may be turned about by the tide or current. the device is one well calculated to meet with a favorable reception from fishermen. improved abdominal corset. christina lascell, newark, n.j.--the object of this invention is to furnish an improved abdominal corset, which supports the weight of the abdomen in a perfectly comfortable and easy manner, and throws the strain on the shoulders and hips of the wearer. the corset is adjustable to the varying conditions of the abdomen, does not interfere with the motion and different positions of the body, and is readily put on and taken off. it has adjustable elastic shoulder straps, and opening at the sides by lacings and elastic bands and buttons. the front part of the corset is stiffened by a stay that slides in a pocket to provide for stooping. a central front and lacing admit the front part of the corset to expand. the lower extension part of the corset has short stiffening stays, and it is connected independently of the upper stays by short side lacing and elastic straps to the side or hip parts of the corset. a hernial band extends from the lowermost part of the corset-extension between the legs to the rear, and is attached by adjustable hip straps to the sides of the corset. improved fire escape. john f. werner, new york city.--the terrible disaster in the brooklyn theater is serving as a stimulus to induce the invention of devices looking to the prevention of a like occurrence. the present inventor has devised a new fire escape for theaters, concert halls, and other public places of amusement, by which the space at the upper parts of the entrances, halls, or vestibules of the buildings is utilized for the purpose of forming additional passage ways for the persons in the buildings, to be used in case of fire for the more convenient and less dangerous exit of the same. the invention consists, mainly, of a movable floor, suspended by chains, pulleys, and weights, near the ceiling of the entrances, and lowered in case of fire. it is supported on projecting rests of the side walls, at suitable height above the floor. sliding extensions and swinging stairs and rear sections connect with the ground outside of the door, and with the staircases of the gallery, so as to form separate exits above the regular entrances. improved electro-magnetic dental plugger. james e. dexter, new york city.--this invention consists, first, in a magnet having a centrally bored iron core, surrounded by a magnetic coil, which is enveloped by an iron shell that is concentric with the central core, and is attached to a flange formed on the lower end of the said central core. one side of both shell and core are split for the purpose of obviating residual magnetism. the invention also consists in combining a spring yoke, a vibrator, and a spring contact piece, as hereinafter particularly described. the third part of this invention consists in the arrangement of the key for completing the circuit, which is made with an insulating exterior, and is provided with one of the termini of the magnet coil, and bears against the side of the key to insure a constant contact of the surfaces. the various parts of the plugger are combined, so that pressing the key with the finger makes the circuit, and a succession of regular strokes is produced, the force of which may be varied by an adjusting screw. * * * * * new mechanical and engineering inventions. improved cotton gin. joseph w. thorn, iuka, miss., assignor to himself and m.w. beardsley, of same place.--in this machine there is a new construction of the brush drum for simplifying the same, and facilitating the application of the brush wings, so that they can be readily taken off and put on; also, an arrangement of the ribs between the saws for facilitating the separating of the seed from the cotton without breaking and injuring the fiber. there are also ingenious devices for preventing the seed from gathering and clogging at the ends of the saw drum. improved safety check for elevators. nathan h. fogg, boston, mass.--when the car is suspended normally from the rope, the rubber balls, arranged in sockets near the lower part of the car, are supported on their seats in a state of rest; but the instant that the rope breaks or gets detached from the bolt the action of a spiral spring throws an actuating plate downward, and levers and ball-carrying rods upward. the balls are thus thrown off their seats and wedged between the inclined sides of the pockets and the guide posts of the elevator so as to stop thereby the car. improved combination lock. achille parise, naples, italy.--this is a new combination lock for doors, trunks, safes, etc., that admits of a large number of combinations, and may be opened and closed quickly. it consists of sliding tumbler plates, having longitudinal slots and a number of perforations placed at different relative positions to the slots of each tumbler. the trunks are connected by screw set pins attached to face slides, and passing through any one of the perforations, admitting the setting of the tumblers and opening of the lock by outer projections or buttons of the slides to fixed exterior guides. improved machine for wiring and binding hats. mari a. cuming and judson knight, new york city.--this is a machine for binding hats, felt skirts, and similar articles, by a uniform and parallel pressure on the rims, and by facilitating the applying and taking off of the articles from the machine, and accomplishing the cutting of the binding or braid and wire in a reliable and improved manner. pressure rollers attach the binding and the wire, if one is required, in connection with a grooved gage that is supported on a seat of the shaft of the lower pressure roller. the wire is guided by annular recesses or chamferings at the rear circumference of the pressure rollers and the groove of the gage. the gage is so connected to its seat that it may be turned and another guide groove of the same be exposed to face the pressure rollers, so as to adapt the same for a variety of work. * * * * * business and personal _the charge for insertion under this head is one dollar a line for each insertion. if the notice exceeds four lines, one dollar and a half per line will be charged._ * * * * * manufs. of scissors address j.w.d.e., harmony grove, ga. for sale-- in. lathe, $ . ; in. lathe, $ . ; in. pratt whiting shaper, $ . ; h.p. loco. boiler, $ ; in. lathe, $ ; at shearman's, n. d st., phila. iron tubing--wanted, a yearly supply of - in. light iron tubing. address p.o. box , new york city. baxter's adjustable wrenches--the best for farmers, householders and mechanics. greene, tweed & co., park place, n.y. for sale--baldwin no. foot lathe and fittings; in perfect order. address p.o. box , clinton, mich. national steam pump--simple, durable, economical. reduced price. national iron works, n. brunswick, n.j. manufs. and dealers in cotton gins, grist mills, and rice hullers and polishers, address with terms, y.l. ridley, liberty, texas. for sale--patent combination fruit press, filter and funnel. an indispensable article in every household. for circulars, address g.a. newsam, d pl. brooklyn. mill stone dressing diamonds. simple, effective, and durable. j. dickinson, nassau st., n.y. will purchase or introduce, on a reasonable royalty, some good, useful article. address, with description and full particulars, a.e. lowison, boston, mass. mechanical inventors familiar with envelope manufacturing. l.j. henry, kearny st., san francisco, cal. set of mechanical curves, as illustrated in sci. am. supplement, no. , mailed on receipt of $ . , by keuffel & esser, new york. hyatt & co.'s varnishes and japans, as to price, color, purity, and durability, are cheap by comparison than any others extant. grand st., n.y. factory, newark, n.j. send for circular and descriptive price list. lightning screw plates. a perfect thread at one cut adjustable for wear. frasse & co., chatham st., n.y. wire needle pointer, w. crabb, newark, n.j. power & foot presses, ferracute co., bridgeton, n.j. superior lace leather, all sizes, cheap. hooks and couplings for flat and round belts. send for catalogue. c.w. arny, north d st., philadelphia, pa. f.c. beach & co., makers of the tom thumb telegraph and other electrical machines, have removed to water st., n.y. for best presses, dies, and fruit can tools, bliss & williams, cor. of plymouth and jay sts., brooklyn, n.y. water, gas, and steam pipe, wrought iron. send for prices. bailey, farrell & co., pittsburgh, pa. walrus leather and supplies for polishing iron, steel, and brass. greene, tweed & co., park place, n.y. hydraulic presses and jacks, new and second hand. lathes and machinery for polishing and buffing metals. e. lyon, grand st., n.y. solid emery vulcanite wheels--the solid original emery wheel--other kinds imitations and inferior. caution.--our name is stamped in full on all our best standard belting, packing, and hose. buy that only. the best is the cheapest. new york belting and packing company, and park row, new york. steel castings from one lb. to five thousand lbs. invaluable for strength and durability. circulars free. pittsburgh steel casting co., pittsburgh, pa. m. shaw, manufacturer of insulated wire for galvanic and telegraph purposes, &c., w. th st., n.y. shingle, heading, and stave machine. see advertisement of trevor & co., lockport, n.y. for solid wrought iron beams, etc., see advertisement. address union iron mills, pittsburgh, pa., for lithograph, etc. articles in light metal work, fine castings in brass, malleable iron, &c., japanning, tinning, galvanizing. welles specialty works, chicago, ill. see boult's paneling, moulding, and dovetailing machine at centennial, b. - . send for pamphlet and sample of work. b.c. mach'y co., battle creek, mich. wanted--novel and practical invention, by a reliable house, for manufacturing. address post office, box , chillicothe, ohio. chester steel castings co. make castings twice as strong as malleable iron castings, at about the same price. see their advertisement on page . hand fire engines, lift and force pumps for fire and all other purposes. address rumsey & co., seneca falls, n.y., u.s.a. * * * * * notes & queries * * * * * s.j.s. will find good recipes for laundry soaps on pp. , , vol. . for toilet soaps, see p. , vol. .--b.f.t. will find directions for putting a black finish on brass on p. , vol. .--j.c.s. will find directions for coloring a meerschaum pipe on p. , vol. .--a.b. will find a good recipe for babbitt metal on p. , vol. .--g.a.d. will find directions for coloring butter with annatto on p. , vol. .--l.o.j. will find something on iceboats sailing faster than the wind on p. , vol. .--j.m.l. will find directions for clarifying cotton seed oil on p. , vol. .--d.v. will find a good recipe for shoe polish on p. , vol. .--a.b. will find directions for japanning on metal on p. , vol. .--t.s.d. will find recipes for all kinds of colored fires on p. , vol. .--g.s.c. can fasten his paper labels to wood with flour paste.--w.r.b. will find directions for dyeing billiard balls on p. , vol. .--g.w.m. will find directions for making raisins on p. , vol. .--t.f.t. will find something on burning petroleum in steam boilers on p. , vol. .--s.b.u. will find some illustrations of lathes for turning spokes, tool handles, etc., on p. , vol. .--w.e.p. will find a formula for safety valves on p. . vol. .--a.o. will find directions for removing mildew on p. , vol. . for mending rubber boots, etc., see p. , vol. .--w.c.l. will find directions for preserving eggs on p. , vol. .--r.m.g. will find a recipe for root beer on p. , vol. .--w.f.h.'s plan for a refrigerator might answer. see p. , vol. .--j.c. can remove the wool from pelts by steeping the skins in water, and hanging them up till the wool putrifies. then scrape with a blunt knife. for cleansing wool, see p. , vol. .--w.h.j. will find a recipe for a cement for marble on p. , vol. .--t.b. can gild his steel scabbard by following the directions given on p. , vol. .--a.h.b., j.a.c., w.h.h., j.f.p., d.s., j.n.h., j.p., f.f., m.n., m.c., r.c., k.s.w., t.j., and others, who ask us to recommend books on industrial and scientific subjects, should address the booksellers who advertise in our columns, all of whom are trustworthy firms, for catalogues ( ) r.h.c. says: we have a slate roof which leaks very much. i have not discovered any defect in the way in which it was put on; it appears to be perfect. the pitch may be too low, and the rain may be driven through by the wind on this account. is there any wash, paint, or cement that might be used for the purpose of remedying this defect? a. there is an india rubber paint which is used to make leaky roofs tight, but we have not learned of its being applied to slate roofs. ( ) c.c.b. says: i am making a small steam engine. the cylinder has, inside diameter, about inch with ½ inches stroke. what would be the most suitable material and dimensions for the boiler? a. make one or inches in diameter and inches high, of / inch iron. you can carry lbs. steam pressure. ( ) m.c. says: i have had charge of some greenhouses that were erected about four years ago; they are thoroughly heated, and all the pipes have a thick coat of black paint. the houses never gave any satisfaction, no matter how healthy the plants were in the fall. soon after the fires were lighted both leaves and flowers began to drop, and some plants died. my predecessors attributed it to gas getting into the houses. upon inquiry i found no gas was there except when the pipes were hot, and that the hotter they were the worse it was. in my opinion, the cause of the trouble was a strong smell of paint from the pipes. since then i only keep heat enough to save the plants from freezing. a. from your statement there is no doubt that the paint used on the pipes was an imperfectly purified coal tar. such tar contains a great number of hydrocarbons--naphtha, naphthalen, anthracen, phenol, several organic alkaloids, hydrosulphuric and hydrocyanic acids, etc., all of which are more or less volatile at the temperature to which they must have been subjected. these exhalations have proved fatal to plant life when in sufficient quantity. we do not know of a better remedy than that of removing the cause. painting the pipes with a strong solution of washing soda and lime would, in a measure, prevent the escape of the most objectionable constituents into the air, by forming with them compounds non-volatile at any temperature to which they are likely to be subjected in contact with the pipes; but the former would be the surest plan. ( ) c.d.w. asks: the roof of the new illinois state house, as well as the stylobate cornices and upper portion of the dome, are covered with zinc. it has been on about three years, and i am told is materially affected by oxidation. the theory is that zinc, though subject to oxidization, has the peculiarity that the oxide does not scale off as from iron, but forms a permanent coating impervious to the action of the atmosphere. some mechanics, however, assert that neither zinc, copper, nor lead will withstand the action of our atmosphere, as bituminous coal strongly impregnated with sulphur is almost the only fuel used. it is claimed by some that the sulphurous acid in the atmosphere tends to corrode zinc so as to make it worthless for roofs or gutter linings. a. are you sure that the roof and gutters in question are not of galvanized iron, iron coated with zinc? this is the material most commonly used for that purpose at the present time. zinc has been found to be too brittle for the strain to which it is subjected, in such cases, by the expansion and contraction induced by changes of temperature. a slight oxidation will adhere to the surface, but an acid deposit from the atmosphere will penetrate the coating in points and deteriorate the metal. ( ) n.j.s. says: i have a floor of ash and black walnut which has been oiled with raw linseed oil once. how can i finish it so as to get a hard, smooth finish that will not be scratched by boot heels nor be sticky or retain the dirt as a waxed floor does? a. oil raises the fiber of black walnut and gives it a rougher surface than when free from it. to polish any wood, it is only necessary to fill the pores well, and then rub it down to a smooth surface. thus painters prefer to put on a coat of shellac varnish first, before oiling walnut and other hard woods. for fine floors, a thin coat of liquid wax is applied as a finish. ( ) a.j.s. asks: what is the best plan for putting up a cheap dry house of lumber, for drying (by steam) white oak, hickory, and other lumber used in wagon and buggy making? a. make as tight a house as possible with tongued and grooved siding-boards, floors, roof, etc., and provide a stack of steam pipe containing foot of heating surface to every cubic feet of air contained in the building. set the steam pipe in compact shape and enclose it with a casing of galvanized sheet iron open at the top; supply cold air from outside of the building by a boxed conduit to the bottom of this stack. the air when heated will rise and diffuse itself into the room, and as it cools will fall to the floor; provide registers in the floor, through which it may escape into other boxed tubes under the floor leading to an upright chimney discharging above the roof. let a smoke pipe from the boiler enter the chimney and extend up inside the flue far enough to heat the same. the change of air is necessary to dry the lumber. the size of the house of course will depend upon the quantity of material required to be stacked up into it at any one time. ( ) g. asks: . how do you calculate the amount of pipe of a given size to warm a room of a given size? a. one square foot of plate or pipe surface is generally taken as sufficient to heat about cubic feet of air in dwellings. . what allowance should be made for doors and windows? a. the said foot of surface will heat, in accordance with varying conditions, from to cubic feet of air, and allowance should be made for extra exposures, to correspond with that scale. a steam pressure of lbs. is sufficient for heating purposes. . what is meant by the terms direct and indirect radiation, in giving capacity of steam generators for heating houses? a. direct radiation is used when the pipes are located in the room, and indirect when they are located in a chamber in the cellar, to warm air which is conducted to the room by air pipes. ( ) d.m. says: after reading l.s.w.'s reply to j.b.c., p. ( ), vol. , i think the following demonstration will be more acceptable to j.b.c.: imagine three spheres of which the given circles are great circles, and a plane tangent to the three spheres. any two of the spheres may be conceived to have been generated by the revolution of two of the circles about the line joining their centers. during such revolution, the lines tangent to the two circles describe a conical surface. we have, therefore, three spheres and three conical surfaces. now the plane, which is tangent to the three spheres, is also evidently tangent to the three conical surfaces; and therefore the vertices of those conical surfaces are all in the tangent plane. now those vertices are the points ( ), ( ), ( ). but the same points are also in the plane passing through the centers of the three spheres, which is the same with the plane of the paper on which the figure is drawn. those points, being in two planes at the same time, must therefore be in the intersection of those planes, that is to say, in a straight line. ( ) c.w.h. asks: can dyeing or coloring be done in cold water? a. many of the coal tar colors may be used in this way: for animal fibers--wool, silk, | etc.--the affinity of these colors is so great that, in most instances, no mordants are necessary. the baths are usually made slightly acid. with vegetable fibers, however, a fast dye is not assured without mordanting. some of the finer goods are prepared by treating with steam coagulated albumen (animalizing), gelatin, various tannates, tin salt, alum, and other metallic salts. the following is, the usual method of treatment, except with goods intended for very light shades: pass the goods through a strong decoction of sumac or other tannin solution for an hour, and afterwards for an hour or two through a weak solution of stannate of soda; wring out, dip into a dilute solution of sulphuric acid, and rinse well in water. the goods are then ready to be passed through the color bath, slightly acidulated. for different tints, these baths are worked at different temperatures. ( ) f.w. says: i wish to lay the face tier of a brick wall in black mortar. how can i make the coloring material and mix it? a. some prefer to use red mortar and afterwards pencil the joints with black. color the ordinary white mortar with spanish brown for red mortar, and with ivory black for black, by mixing in enough of the color in a powdered state to give a good deep tone. ( ) h.a.s. asks: . how many prisms are required in a spectroscope to detect mineral elements in presence of all the ash ingredients of organic bodies? a. if we understand you, one ° prism will answer. . what is the best and cheapest form of apparatus to heat such compounds for examination? a. mix the substance with a little pure hydrochloric acid and glycerin, and introduce into the flame on a coil of platinum wire. . has soup prepared by dissolving meat bones in a papin's digester ever been known to produce ossification of any of the soft tissues? a. we have never heard of such a result. . has it ever been known to produce a new crop of teeth in toothless persons? a. we have no data as to such a fact. i have seen a statement that may , , was so dark a day that candles were necessary everywhere; and i have heard that another occurred about the year . has any scientific explanation ever been given of this phenomenon? a. the darkness on the days you mention were the result of solar eclipses. they occurred on days of unusual cloudiness. perhaps the darkest day in modern history was that caused by the total solar eclipse in the year . ( ) a.b. says: . i have built a boat feet long and feet inches wide. how large a boiler and engine do i require to work her to best advantage? she is inches deep from top of rail to top of keel. a. cylinder, ½ x inches; boiler, inches in diameter and feet high. propeller, to inches in diameter, and of feet pitch. . how fast ought she to run? a. probable speed, miles an hour in smooth water. ( ) l.l. asks: . does it make any difference in what position a watch is in when running? a. for watches adjusted to temperature and position, it does not make much difference. . when not being carried, what position should it be left in? a. in the case of ordinary watches, we imagine that the wear will be rather more uniform when they are in a vertical position. . if a person sleeps in a cola room, would a watch be better under his pillow than on a table or hung up in the same room? a. it is best not to subject them to great changes of temperature. ( ) w.g. says, in reply to c.w.w., who has an engine, of - / inches bore and inches stroke, which runs slower with increase of pressure: having had much experience with small engines and boilers, i will state that i have had the same difficulty when using an upright tubular boiler, and discovered the following to be the cause: the upper portions of the tube superheat the steam to such a degree as to prevent lubrication on the valve and piston surface by condensation, and thereby reduce the speed of engine. even with increased pressure, this effect will be more appreciable when the area and travel of slide valve are in excess. ( ) j.m.t. asks: is there friction between two bodies while at rest, or only when one or both are in motion? a. both when at rest and in motion. why does a balloon rise in the air? a. see p. , vol. . ( ) s.j.s. asks: . how are augers twisted? a. by special machinery. . how are twist drills made, and are they single or double grooved? a. they are double grooved or double twisted, and are cut out in a milling machine. can weights, springs, or water from a tank be used to any advantage to run a lathe? a. no. how much do iron and brass, in rods or bands, expand in length when heated to red heat? a. iron about / inch per foot, brass / inch. is the pressure of the air to be added to the weight of water in the bottom of a vessel in estimating the pressure on the bottom? a. no. does a watch or clock run faster when just wound up? a. no. is it not moisture in the air that makes it heavier, and so affects the barometer? a. yes. is the pressure in a siphon equal throughout, or is it greater in the upper end? a. equal throughout. will it take more power to run two millstones in opposite directions than it will to run one at the same speed, the other being stationary? a. yes, it will take double the power. . how are common screws made? a. in lathes, with tools and dies. . how can i make wooden screws perfectly smooth? a. by using keen tools. what is the simplest way of cutting a square hole in a bar of iron? a. drill a round hole and square it out. ( ) g.e.c. asks: could i have a brick range Ã� feet, built on a platform about foot from floor, with two compartments, to be heated with petroleum, the lower one to be used as an oven, the upper one to have a stove top to set cooking utensils on, and have a ventilating pipe run from each compartment of the oil receptacles into the place in the chimney where the stove pipe usually goes, to carry away any gas or smoke? i want the oil receptacles to be arranged to be drawn out, to be filled and trimmed, and i would like four burners to heat an oven inches square, as hot as the same oven could be heated with wood. a. we doubt the propriety or the economy of substituting oil for wood, but something may be done to make the atmosphere of kitchens more endurable in summer, and permanently so in warm climates. a double faced range could be made and set in the center of the thickness of the chimney, with the space above the top of it open to the exterior of the house; a very slight structure, simply having a good floor and roof and open around the sides, and built against the chimney as an extension to the house, would answer for a summer kitchen, while the ordinary kitchen inside the house could be used in winter. the transposition could be made by a pair of iron sliding doors shutting off the kitchen not in use; and these doors could be transferred from one side of the chimney to the other when the change of season required it. ( ) a.x.a. says: in your issue of december is a recipe in which "insoluble acid chromate of lime," and gelatin are to be used; and in a succeeding number of your paper the modes of preparing the insoluble acid are given. i have made the acid according to your directions, but the result of my manipulation of the recipe is a failure. you say: "take of insoluble acid chromate of lime one part, and of gelatin five parts;" but you do not say what further is to be done. will the acid dissolve the gelatin, or must warm water be added? in my experiment the acid would not dissolve the gelatin, and i had to add considerable warm water before it would do so. a. dissolve the bichromate of lime in the smallest possible quantity of warm water, and filter; then add the gelatin, previously softened by immersion in cold water. heat the mixture over a water bath until the gelatin is completely dissolved, stir well, and use while hot. the recipe should have stated that this cement was best suited for glassware. the bichromate of potash or of ammonia will answer nearly as well as the lime salt. ( ) e.c.n. asks: how must a stove be constructed to burn pea coal, for heating outbuildings? is there any way of constructing a draught below the grate of any common heating stove, sufficiently strong to do without an extra long chimney? a. use a broad grate to spread the coal out well, so as to avoid the necessity of heaping it up much; make the opening for the draft some distance below the grate, and regulate by the usual slide dampers in the lower and upper doors. minerals, etc.--specimens have been received from the following correspondents, and examined, with the result stated: f.r.r.s.--the substance you send is carbonate of iron. it is held in solution in the water by the large excess of carbonic acid which the water contains. on boiling the water the carbonic acid gas is expelled and the iron salt is precipitated from solution. the removal of this and some other objectionable salts which the water very probably contains, may be removed by the addition of the proper quantity of clear lime water to it--the lime in this instance will combine with the excess of carbonic acid and fall to the bottom together with the carbonate of iron. to determine the precise quantity of lime water requisite, add the reagent (saturated solution) to a small portion (of known volume) of the freshly drawn water, in small quantities at a time, and with constant stirring until no further precipitate forms. then by a simple operation in proportion the quantity of the reagent necessary for the purification of a given quantity of the well water may be easily determined. an excess of the reagent must be avoided. this impurity would probably prevent the successful working of an injector. w.s.w. asks: how is the best rosin, used on violin bows, prepared?--w.f. asks: what is a simple method for washing clay for brick and tile making?--e.s.d. asks: what is the best kind of wood to construct a guitar? * * * * * communications received. the editor of the scientific american acknowledges, with much pleasure, the receipt of original papers and contributions upon the following subjects: on rheumatism. by a.r.e. on postage stamps. by e.b. on boiler explosions. by g.b.b. on reaching the north pole. by j.h.s. on heating street cars. by p.t. on a hybrid fruit, by r.s.b. on an air vessel. by j.t.r. also inquiries and answers from the following: e.b.m.--f.f.f.--n.b.h.--b.b.--o.f.--r.v.j.--f.m.--n.b.c.--c.f.e.--w.t. --c.w.c.--t.f.--c.a.s.--s.n.m.--j.r.d.--p.j.d.s. * * * * * hints to correspondents. correspondents whose inquiries fail to appear should repeat them. if not then published, they may conclude that, for good reasons, the editor declines them. the address of the writer should always be given. inquiries relating to patents, or to the patentability of inventions, assignments, etc., will not be published here. all such questions, when initials only are given, are thrown into the waste basket, as it would fill half of our paper to print them all; but we generally take pleasure in answering briefly by mail, if the writer's address is given. hundreds of inquiries analogous to the following are sent: "who sells a tool for truing up a crosshead wrist? who sells tools for refitting steam valves without unscrewing them from the pipes? who sells spoke-turning lathes? who makes machinery for freeing wool of burrs and dirt? where can tungsten, or tungsten steel, be procured, and at what price? who sells silicate of alumina and silicate of potash?" all such personal inquiries are printed, as will be observed, in the column of "business and personal," which is specially set apart for that purpose, subject to the charge mentioned at the head of that column. almost any desired information can in this way be expeditiously obtained. * * * * * official. index of inventions for which letters patent of the united states were granted in the week ending january , , and each bearing that date. [those marked (r) are reissued patents.] * * * * * a complete copy of any patent in the annexed list, including both the specifications and drawings, will be furnished from this office for one dollar. in ordering, please state the number and date of the patent desired, and remit to munn & co., park row, new york city. * * * * * abdominal corset, c. lascell , acoustic telegraph, t.a. edison , advertising card, h. mahler , air compressor, j. clayton , air compressor, w.f. garrison , animal trap, t.n. hughes , annealing furnace, h.b. chess , atomizer, w. kennish , axle tree, trussed, j.b. brewster , barbed fence, c.f. washburn , bee hive, g.w. akins , belt shipping attachment, r. denmark , blotter and paper clip, c.b. farrington , bone black, cooling, c. doscher , book back, metallic, i. reynolds , bottle and basket, e. cusenier, sr , bottle for hair dye, t. divine , bottle stopper, e.b. requa , bread cutter, g.b. heath , brick and tile lifter, braislin & wood , broom, w.m. jackson , brush handle, i.l. landis , buckle, g.f. eberhard , buffing roll, l.s. graves , butter press, w.s. alexander , button, d. wilcox , call bell, a.c. gould , car axle lubricator, r. macdonald , car coupling, o. & m. crum , car coupling, j.w. skeele , car roof, h. aldridge , car roof, h. aldridge , cards for fibers, making, yates & kellett , cartridge, j.p. white , chamber vessel, j.c. moore , clamp for ratchet drills, l. beland , cloth, folding and scouring, r.d. nesmith , clothespin, w.s. davis , clutch, a.b. bean , coffee pot, w.w. stevens , combination lock, a. parise , combination lock, g. winter , combination tool, i.u. malphurs , combustible, j.b.d. cassinelli , corn planter, w. gilman , corn planter, j.l.g. schmidt , corn planter and cultivator, e.c. gage , corn popper, g.p. sisson , corset, j. mayer, , cotton gin, j.w. thorn , cotton holder, dental, t. cogswell , curtain fixture, collins & saltsgaver , curtain fixture, j.b. marshall , dial telegraph, j.h.c. watts , door and gate fastener, j. gibbs , door hanger, w.e. warner , door retainer, r.e. dietz , drop light, j.a. evarts , egg beater, g.p. sisson , egg carrier, l. inglee , electric gas lighting, c.h. hinds , electro harmonic telegraph, e. gray , electric dental plugger, j.e. dexter , elevator, safety check, n.h. fogg , fabrics, winding up, g.e. jones , feed apparatus, punching, j. morgan , feed bag for horses, g.c. booth , fence post, p.j. rickard , fire place, h.f. watson , fire place heater, j.k. dimmick , fire place, portable, t.c. nativel , fish scrap, treating, s.l. goodale , fly fan, h.b. baker , fly fan, w.r. fowler , folding chair, b f. little , friction wheel, e. brauer , fruit or paint can, w.h. fowler , furnace, evaporating, j. kitchen , furnace, smelting, g.w. swett (r) , gang plow, w. fruhling , gang plow, e. peak , gas and air carbureter, boomer & randall , gas governor, j.r. blossom , gas, manufacturing, j g. hunt , gas retort cover, a. schwarz , gate, d. scherer , gill net, d.w. & s.h. davis , grafting machine, e. walters , grain binder, j.m. rosebrooks , grain separator, o.j. chubbuck , grain separator, t.j. doyle , grubbing machine, i. burley , hand truck, h.r. ferris , hat bodies, washing, t.c. beatty , hats, wiring and binding. cuming & knight , hay tedder and side rake, huber & snell , high pressure hot air engine, o. stenberg , hook for drawrods, m.b. eskine , hoops, racking, s. parker , horse power, traverse pinion, j.a. field , horseshoe, weighted, e.e. seixas , hose nozzle, m.s. curtis , hot air furnace, j.c. sanborn , hydraulic motor, j.m. bois , indexer, j. suter , indicator for liquids, i. levi , insects, destroying, j.b. margarit , iron fence, nellis & guttridge , key board, musical, b. bishop , knob roses to doors, w.a. barlow , lamp burner, h.h. doty , lamp chimney, s.w. fowler (r) , lathe chuck, metal, j.h. harris , leather-covered nut, l.t. smith , letter scales, j.v.h. nott , lifting jack, c.f. davis , lifting jack, f.m. lottridge , lifting jack, d.m. ross , lighting alarm clocks, h.j. & w.d. davies , limekiln, j.w. devling , lock for drawers, etc., g.w. baker , locomotive engine, w. wells , loom, l.j. knowles , loom, smith & skinner , looms, preparing warps for, w. heaton , molasses gate, s. barker , multifold pipe coupling, e.a. leland , muzzle bit for horses, a.j. short , newspaper file, p.e. sloan , odorless air closet, g.r. moore , odorless receptacle, g.r. moore , oiler, s.s. newton , ordnance, s. crispin , ore and coal jigger, g. schmauch , ores, process of treating, g.d. wyckoff , paper box, r.h. foster , paper, cloth, etc., machine for cutting, e. allen , paper cutting machine, p. mcaleer , paper dish, s.e. harlow , paper folding machine, l.c. crowell , paper, folding, s.d. tucker , , , pasting machine, t. goodall , piano forte attachment, e. zachariae , pins, dowels, etc., cutting, f.h. kane , pipes bursting, preventing, a. bujac , plaiting machine, e.s. harding , plane irons, adjusting, j.a. traut , plate for stoves, n.m. simonds , plow attachment, d.w. hughes , plow stock, r. weber , powder, compensating, miltimore & totten , printing telegraph transmit, g.m. phelps , pulleys from shafting, drawing, h.f. casterline , pulverizing machine, a.b. lipsey , pump, g.r. mccrum , quilting frame, h.t. davis , railway brake apparatus, h.f. knapp , railway car, s.r. & o.v. wallace , rake, self-cleaning, v.w. blanchard , refrigerating car, j.m. ayer (r) , refrigerator, g.h. crisfield , refrigerator, j.w. stewart , registering fare box, j.c. strong , reversing valve, engine, bevins, weis & phillips , riding saddle, j.c. miller , rotary engine, d.r. harder , sad iron, baker & asbury , sample garment, l.e. warner , saw set, c. heinen , saw table, g.e. burt , screw for piano stools, g.w. archer , seat, reversible, j.e. rugg , seed planter, d.j. davis , seed sower, j. pearce , seeder and cultivator, w.a. van brunt (r) , separating germs from grain, c.a. duprez , sheep shears, porterfield & malin , sheet metal can, j.s. field , shirt stud, c.h. field , shot cartridge, j.p. white , sock and stocking, j.l. krauser , socket for scythe shanks, m. smith , sofa bedstead, h. compes , spark arrester, w.s. hudson , spark arrester and consumer, t.e. roberts , spinning frame, g. draper , spinning frame, ring, g. draper , spinning frame, ring, w.f. draper , spinning machine, g. draper , spring back wagon seat, j.w. wood , spring bolt for sliding doors, etc., a. hance , spring for wagons, auxiliary, a.w. mckown , stalls, cutting, j.m. goff (r) , stencil plate, wright & bryant , stove, m.l. wood , stove pipe, a.b. allen , straw cutter, d. maxwell , tempering steel, etc., g.f. simonds (r) , , , tension regulator, g. draper , ticket case, s. strandgaard , time attachment for locks, j. sargent , time lock, e.j. woolley , toothbrush, s. woolverton , toy card shooter, c.w. frost , tubular gang saw, j.a. balch , underground telegraphs, w. mackintosh , , , valve gear of engines, link for, j.h. luther , vapor burner, w.c. north , variable cut-off, j. fish , vehicle wheel, h. mounts , vehicle wheel, g.f. almy , velocipede, stineman & halloway , vent clearer for wash bowls etc., j.s. hawley , ventilator, j.b. hill , vessels, lessening draught of, e. ellison , wagon end gate, t.l. black , water closet trunk, e.a. leland , weaning bit for animals, j.p. israel , weather strip, e.c. underwood , whirling toy, j.h.jenkins , wrench, p. chapin, sr , * * * * * designs patented. , , , .--chains.--d.a. beam, newark, n.j. , .--brackets.--o.f. fogelstrand, kensington, conn. , .--bottle.--a.t. francis, paterson, n.j., et al. , , , .--carpets.--a. heald, philadelphia, pa. , .--carpets.--d. mcnair, boston, mass. , , , .--carpets.--t.j. stearns, boston, mass. , .--bronze.--j.w. tiemann et al., darlington, n.j. , .--shirt front.--s. weill, new york city. , .--desk.--j.h. frink, detroit, mich. [a copy of any of the above patents may be had by remitting one dollar to munn & co., park row, new york city.] * * * * * advertisements. * * * * * inside page, each insertion cents a line. back page, each insertion $ . a line. _engravings may head advertisements at the same rate per line, by measurement, as the letter press. advertisements must be received at publication office as early as friday morning to appear in next issue._ * * * * * water wheels. more than four times as many of jas. lefell's improved double turbine water wheels in operation than any other kind. sizes made, ranging from - to in. diam. under heads from to ft. successful for every purpose. large new pamphlet, the finest ever published, containing over fine illustrations, sent free to parties interested in water power. [illustration] jas. leffel & co., springfield, o., and liberty st., new york city. * * * * * steel castings, from - to , lbs. weight. an invaluable substitute for expensive forgings or for malleable iron castings requiring great strength. send for circular and price list to chester steel casting company, evelina street, philadelphia, pa. * * * * * george c. hicks & co., baltimore, md. clay retorts, tiles, fire bricks, &c. terra cotta pipes of all sizes. * * * * * cheapest rotary hand cornsheller in the u.s. guaranteed to be the simplest, cheapest, most durable, effective and the best. buy it. try it and be convinced. samples $ . . large profits to agents. address harrisburgh pa., family cornsheller co. lock box . * * * * * y.a. fay & co. cincinnati, ohio u.s.s. wood working machinery. woodsworth planers and matchers, daniels & dimension planers, universal wood workers, band & circular re-saws, ripping, edging & cross-cutting saws, molding, mortising and tenoning machines, band & scroll saws, carving, boring, shaping, friezing & sand papering machines, wood lathes & machinery for furniture, car, wheel & agricultural shops. superior to any in use. prices reduced to suit the times. * * * * * dayton cam pump. the only pump in the market designed and constructed especially for boiler feeding. are pumping water at ° f. no dead centers. the steam valve is a plain slide valve identical to the slide valve of a steam engine, but derives its motion from a cam. speed can be regulated to suit evaporation. pumping returns from steam heating apparatus a specialty. send for circular. smith, vaile & co., dayton, ohio. [illustration] * * * * * wanted the sole manufacture for england, of one or two patent articles in demand by steam users. advertisers have good manufacturing premises, and a first-class connection among steam users in england and the continent. apply in first instance by letter to p.s.b., care of mr. g. street, advertising offices, cornhill, london, e.c., england. * * * * * a new year's gift a $ new year's gift given away! to every reader of this paper! consisting of the beautiful and valuable steel engraving, entitled "christ in the temple!" in an american edition, issued by w.w. bostwick & co., publishers, and west fourth street, cincinnati, o., and furnished to every reader of this paper free. the retail price of the english edition of this engraving is $ . per copy. it illustrates one of the most remarkable incidents in the life time of our savior. the subject is taken from luke, second chapter, , , , , and th verses. its size is three feet long and two feet wide, and has over figures represented. it is the best premium ever given away. w.w. bostwick & co. will supply every reader of this paper with the valuable and appropriate engraving of "christ in the temple" as a new year's gift. a new years gift readers will therefore please cut out the following certificate and send it to w.w. bostwick & co., publishers, and west fourth street, cincinnati, o., for redemption, together with cents to pay for postage, wrapping, roller, and mounting the engraving. cut out this readers' certificate. it is worth $ . . certificate. on receipt of this certificate, together with cents to pay for postage, roller, wrapping, and mounting, we will send the beautiful engraving, three feet long and two feet wide, entitled "christ in the temple," to every reader of this paper, by mail, postpaid. send for engraving at once, stating name in full, p.o. address, county, and state, address all orders to w.w. bostwick co., publishers, . & w. fourth st., cincinnati, o. readers of this paper will be allowed this new year's premium gift, and all orders must be accompanied with above certificate, which be sure to cut out and send with directions for mailing to w.w. bostwick & co., publishers, and west fourth street, cincinnati, o. a new year's gift copyright secured * * * * * a man of a thousand. having discovered, in a manner which might be considered almost providential, a positive cure for consumption and all lung complaints, i feel it my duty to make it known in a practical manner by furnishing a sample bottle, free of charge, to all sufferers, my only hope of remuneration being that the medicine will perform all i claim for it. the ingredients are of the choicest herbal products and perfectly safe; will be sent free to all. address at once. dr. o. phelps brown, grand st., jersey city, n.j. * * * * * i have acres of land in san jacinto county, texas. rolling and heavily timbered, with two spring branches running through the land. the entire tract suitable for farming purposes. title perfect. at the present valuation of land in the neighborhood, its worth five dollars per acre. the bast and west narrow gauge r.r. when completed will run within easy distance of the land, which will increase its value materially. i will give a warranty deed to the above tract of land in exchange for one -horse power portable engine, and -horse boiler return flues, new and complete-geared to run sugar mill without band and gin with band. the machinery to be delivered at depot in liberty. any reference given desired. address y.l. ridley, liberty, liberty county, texas. * * * * * $ for best pianos in the world --in use all over the u.s. in over towns by persons you will find in our illustrated circular, probably residents of your own place, or very near, where you can try our pianos. genuine rosewood--overstrung --full iron plate-- - octaves--agraffe--and possessing every improvement known, and warranted years by a responsible incorporated manufacturing co., referring by permission to the chemical national bank, new york city, by far the strongest bank in america. pianos sent everywhere on trial. we have no agents. send for illustrated circular giving full particulars. address united states piano company. broadway, new york. (please name this paper.) * * * * * practical treatise on the properties of continuous bridges. by charles e. bender, c.e. illustrated. being no. , van nostrand's science series. mo. boards, cents. _recently published._ the fatigue of metals under repeated strains, with various tables of results of experiments, from the german of prof. ludwig spangenberg, with a preface by s.h. shreve, a.m. mo. bound, cents. d. van nostrand, publisher, murran street, and warren street. [ stars] copies sent free by mail on receipt of price. * * * * * wanted--a second-hand shaping machine; inch stroke; in good condition. pratt & whitney's make preferred. address, with full particulars as to size, make, and price, r.g.e., lorimer street, greenpoint, l.i. * * * * * wood-working machinery, such as woodworth planing, tongueing, and grooving machines, daniel's planers, richardson's patent improved tenon machines, mortising, moulding, and re-saw machines, and wood-working machinery generally. manufactured by witherby, rugg & richardson, salisbury street, worcester, mass. (shop formerly occupied by r. ball & co.) * * * * * brainard milling machines all styles and sizes. universal milling machines from $ upwards; brown's patent screw machines. &c., &c. address brainard m.m. co., milk st., boston, mass. * * * * * agents to control territory, west and south (new england states, connecticut excepted, taken), for the sale of the "eureka button fasteners," patented . no tool required to put them on. samples, &c., free. w.l. urann, m'f'r, fulton st., new york. * * * * * engines and boilers. new and complete. one -horse power, $ : h.p., $ ; h. p., $ ; h.p., $ ; h.p., $ , ; all sizes in proportion. patterns, drawings and models best and cheapest of any. address pond grand st. n.y. * * * * * _founded by mathew carey, ._ baird's scientific book catalogues now ready, new revised editions. of our valuable scientific book catalogues, which will be sent by mail gratis, and free of postage, on application. we are now receiving and keeping in stock the most important english and american scientific books as they are published, and are prepared to furnish them or to give information in regard to all american and foreign publications in this department of literature. henry carey baird & co., industrial publishers, booksellers & importers, _ walnut street, philadelphia._ * * * * * air compressors for all purposes. _a specialty of heavy pressures._ the norwalk iron works co., south norwalk, conn. * * * * * otis' safety hoisting machinery. otis bros. & co., no. broadway, new york. * * * * * wrought iron _beams and girders_ the union iron mills, pittsburgh, pa., manufacturers of improved wrought iron beams and girders (patented). the great fall which has taken place in the prices of iron and especially in beams used in the construction of fire proof buildings, induces us to call the special attention of engineers, architects, and builders to the undoubted advantages of now erecting fire proof structures; and by reference to pages & of our book of sections--which will be sent on application to those contemplating the erection of fire proof buildings--the cost can be accurately calculated, the cost of insurance avoided, and the serious losses and interruption to business caused by fire; these and like considerations fully justify any additional first cost. it is believed, that were owners fully aware of the small difference which now exists between the use of wood and iron, that in many cases the latter would be adopted. we shall be pleased to furnish estimates for all the beams complete, for any specific structure, so that the difference in cost may at once be ascertained. address carnegie, bros. & co., pittsburgh, pa. * * * * * arsenic in the arts.--a lecture before the medical association of central new york. by s.a. lattimore, ll.d., professor of chemistry in the rochester university. a popular and important paper. scientific american supplement no. . price, cents. to be had at this office and of all newsdealers. * * * * * a new departure. traveling and local salesmen wanted. staple goods. no peddling. salary $ a month. hotel and traveling expenses paid, s.a. grant & co., manufacturers of envelopes and paper. , , , and home st., cincinnati, ohio. * * * * * $ a week in your own town. terms and $ outfit free. h. hallett & co., portland, maine. * * * * * messrs. b. dambacher & co., hamburg, germany dealers in american wood-working machinery and tools of all kinds. messrt. d. & co., solicit consignments from american manufacturers. catalogues and descriptive circulars desired, by mail. * * * * * machinery of every description, cold rolled shafting, hangers, pulleys, couplings, belting, tanite emery wheels and grinders, in stock. george place, chambers & reade sts., new york city. * * * * * $ to $ invested in wall st. often leads to wealth. a page book explaining everything, and a copy of the wall street review, sent free. john hickling & co., bankers and brokers broadway, new york * * * * * we enamel in fine jet black every variety of turned woodwork parts of machinery, casting's, tinware and other metalwork, enameled jet goods, in wood or metal, made to order. american enamel co. warren st., providence, r.i. * * * * * a gift by an arrangement with the publisher we will send every reader of this paper a sample package of transfer pictures free. send ¢. stamp for postage. they are highly colored, beautiful, and easily transferred to any object. agents wanted. j.l. patten & co., william st., new york. * * * * * flowers _strong plants_ delivered, _free of cost_ safely per mail at your door. satisfaction guaranteed. splendid assortment of roses for $ ; for $ . send for _new catalogue of plants._ hoopes, bro. & thomas, cherry hill nurseries. west chester. pa. * * * * * shafts. pulleys. hangers couplings etc. in stock, and for sale by william sellers & co., philadelphia, and liberty st., new york. price lists and pamphlets on application. * * * * * wanted salesmen to sell light hardware to _dealers,_ no peddling. salary, $ , a year. hotel and traveling expenses paid. address defiance m'f'g co., chicago, ill. * * * * * [illustration] barnes foot power machinery. invaluable machines for mechanics and amateurs. also fancy woods and designs. send for page illustrated catalogue, free. w.f. & john barnes, rockford, winnebago co., ills. * * * * * celebrated foot lathes. [illustration] foot power, back-geared screw lathes, small hand and power planers for metal, small gear cutters, slide-rests, ball machine for lathes, foot scroll saws, light and heavy, foot circular saws. just the articles for amateurs or artisans. highly recommended. send for illustrated catalogues. n.h. baldwin, laconia, n.h. * * * * * pond's tools. engine lathes, planers, drills, &c. send for catalogue. david w. pond, successor to lucius w. pond, worcester, mass. * * * * * l. smith hobart, president. john c. moss, superintendent. d.j. carson, general agent. photo engraving co. moss' process no. park place new york [illustration] relief plates in hard type metal, for printing all kinds of pictorial illustrations in books, newspapers, and catalogues. these plates are an excellent substitute for woodcuts, being used in precisely the same way, giving equally good results for much less money. electrotypes and stereotypes are made from them in the usual manner. we offer special advantages to manufacturers and inventors, as our mechanical work is of the best quality and rapidly executed. our plates are used satisfactorily in the scientific american and the scientific american supplement, and by manufacturers and publishers in all parts of the country. "copy" we work direct only from prints or properly prepared pen and ink drawings. any other copy may be furnished, such as photographs, pencil sketches, or the articles themselves, in which cases we have drawings made in the best manner by our own trained draughtsmen. photographs, taken in the ordinary way, are suitable, and they may be of any size. we make the plates larger or smaller, as desired. we are glad to have customers prepare their own pen drawings, and append one or two, directions to artists: the most important requisite in drawings for our use is that every line shall be _perfectly black._ the paper or drawing board must be _white_ and _smooth_. for fine work drawings should be made double the scale of the plate desired. carefully observing these main points, the artist has the utmost freedom in his choice of styles of drawing. for further information and fine samples of our work, send stamp for current number of our illustrated _quarterly circular_. * * * * * we also publish, | list of engravings. price one dollar | . the letter writer. art album | . the crossing sweeper. containing | . the royal princesses. twelve beautiful photo engravings | . the skein winder. suitable for framing | . the spanish sisters. reproduced by moss process from | . a rest on the hill. art journal steel engravings | . the fair correspondent. published by | . barthram's dirge. photo engraving co. | . going to school. park place | . peep o'day boy's cabin. | . the scanty meal. | . the amazon. printed on heavy toned plate paper, Ã� inches. liberal discount to the trade. sent postpaid on receipt of price. _please say where you saw this._ photo-engraving co., park place, new york. * * * * * [illustration] the trade engine. noiseless in operation--perfect in workmanship--all light parts of cast steel. every engine indicated, and valve corrected to give the highest attainable results. warranted superior to any semi-portable engine in the market! send for price list and circular. herrmann & herchelrode m'f'g co., dayton, ohio. * * * * * wood-working machinery. patent scroll saws and band saws a specialty. over machines in use. medal at cincinnati industrial exposition. agents in all large cities. cordesman, egan & co., m'f'rs, cincinnati, o * * * * * [hand->]send for _descriptive catalogue_ of reliable vegetable and flower seeds containing pages on seeds and plants mailed free. h.a. dreer, seedsman and florist, philada. * * * * * [illustration] $ . reward. $ . this moustache produced on a smooth face by the use of dyke's beard elixir without injury, or will forfeit $ . price by mail in sealed package cents, for three cents. a.l. smith & co., ag'ts, palatine, ill. * * * * * [illustration] j.h. blaisdell's moulder, north th st., philadelphia, pa. * * * * * [illustration] shaping machines have novel device for changing length of stroke while in motion, also, automatic down feed, and quick return. four sizes. patented , , , wood & light machine co. worcester, mass. manufacturers of all kinds of iron working machinery shafting, pulleys, &c. * * * * * $ a day at home. agents wanted. outfit and terms free. true & co., augusta, maine. * * * * * lathes, planers, shapers, drills, gear & bolt cutters, &c. e. gould, newark, n.j. * * * * * snyder's little giant steam engine the best small power engines in the country. ward b. snyder fulton str. new york [illustration] one-horse power, with tubular boiler complete, only $ two-horse power three-horse power call and examine or send for illustrated catalogue * * * * * see photographic apparatus & chemicals complete, with directions, $ . no toy; takes pictures x ½ inches. send for illustrated circular. b. morgan, ann st. new york, p.o. box . * * * * * wanted! salesmen at a salary of $ a year to travel and sell goods to dealers. no peddling. hotel and traveling expenses paid. address. monitor manufacturing co., cincinnati, ohio. * * * * * $ each week to agents. goods staple. , testimonials received. terms liberal. particulars free. j. worth & co. st. louis, mo. * * * * * $ to $ a week to agents. $ _outfit free_. p.o. vickery, augusta, maine. * * * * * the compound steam pump uses steam expansively, hence economically. simpler than any other. only two moving parts in cylinder. no levers, springs, tappets, or reversing valves. critical examination invited. address e. & a. betts, wilmington, del. * * * * * beautiful cards, with name, cents, post paid. millport printing co., millport, n.y. * * * * * spare the croton and save the cost. driven or tube wells furnished to large consumers of croton and ridgewood water. wm. d, andrews & bro., water st., n.y. who control the patent for green's american driven well. * * * * * vinegar. how made in hours from cider, wine or sorghum without using drugs. name paper and address f.i. sage, springfield mass. * * * * * agents. page illustrated catalogue, free. boston novelty co., boston, mass. * * * * * the toll-gate! prize picture sent free! an ingenious gem! objects to find! address, with stamp, e.c. abbey, buffalo, n.y. * * * * * $ made by one agent in days. new articles. samples free. address, c.m. linington, chicago. * * * * * lightning screw plate. [illustration] will make a perfect thread at one cut, and can be adjusted for wear. send for catalogue to the agents, frasse & company, dealers in fine tools, files, steel wire & supplies, chatham street, new york. * * * * * advertisements. inside page, each insertion--- cents a line. back page, each insertion--- $ . a line. _engravings may head advertisements at the same rate per line, by measurement, as the letter press. advertisements must be received at publication office as early as friday morning to appear in next issue._ * * * * * guardiola's coffee & sugar machinery coffee, mait, corn, cocoa, and grain-drying machine. coffee-hulling and polishing machines. coffee-washing machine. helix sugar evaporator. messrs. c. adolphe low & co., cedar street, messrs. munoz & espriella, pine street, new york, are mr. guardiola's agents, and they will give prompt attention to all orders for any of the above machines. * * * * * four grand prize medals! awarded our exhibit at the centennial! [illustration: bliss's select garden seeds.] bliss's illustrated seed catalogue and amateur's guide to the flower and kitchen garden.-- pages, including several hundred finely executed engravings, and a beautifully colored lithograph, cents. bliss's illustrated gardener's almanac and abridged catalogue.-- pages. embraces a monthly calendar of operations, and a price list of all the leading garden, field and flower seeds, profusely illustrated, with brief directions for their culture. cents. bliss's illustrated potato catalogue contains a descriptive list of all the varieties recently introduced, with many other desirable sorts; also much useful information upon their cultivation. cents. b.k. bliss & sons, barclay st., (p.o. box .) new york. please state that you saw this advertisement in the scientific american. * * * * * wanted.--a first-class mold maker on undertakers' hardware. address crane, breed & co., cincinnati, o. * * * * * [illustration: patents] [established .] munn & co.'s patent offices. the oldest agency for eliciting patents in the united states. _thirty years' experience._ more patents have been secured through this agency, at home and abroad, than through any other in the world. they employ as their assistants a corps of the most experienced men as examiners, specification writers, and draughtsmen, that can be found, many of whom have been selected from the ranks of the patent office. sixty thousand inventors have availed themselves of munn & co.'s services in examining their inventions and procuring their patents. munn & co., in connection with the publication of the scientific american, continue to examine inventions, confer with inventors, prepare drawings, specifications, and assignments, attend to filing applications in the patent office, paying the government fees, and watch each case, step by step, while pending before the examiner. this is done through their branch office, corner f and th sts., washington. they also prepare and file caveats, procure design patents, trade marks, and re-issues, attend to rejected cases (prepared by the inventor or other attorneys), procure copyrights, attend to interferences, give written opinions on matters of infringement, furnish copies of patent business, both in this and in foreign countries. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. patents are often sold, in part or whole, to persons attracted to the invention by such notice. patents obtained in canada, england, france, belgium, germany, russia, prussia, spain, portugal, the british colonies, and all other countries where patents are granted, at prices greatly reduced from former rates. send for pamphlet pertaining specially to foreign patents, which states the cost, time granted, and the requirements for each country. copies of patents. persons desiring any patent issued from to november , , can be supplied with official copies at reasonable cost, the price depending upon the extent of drawings and length of specifications. any patent issued since november , , at which time the patent office commenced printing the drawings and specifications, may be had by remitting to this office $ . a copy of the claims of any patent issued since will be furnished for $ . when ordering copies, please remit for the same as as above, and state name of patentee, title of invention, and date of patent. a pamphlet, containing full directions for obtaining united states patents, sent free. a handsomely bound reference book, gilt edges, contains pages and many engravings and tables important to every patentee and mechanic, and is a useful handbook of reference for everybody. price cents, mailed free. address munn & co., publishers scientific american park row, n.y. branch office--corner of f and th streets, washington, d.c. * * * * * emerson's patent damascus tempered saws patent planer, clipper, lumberman's clipper, from clipper cross-cut, universal adjustable saw swage, band saws for saw mills and re-sawing, and solid saws of all kinds. are superior to all others, extra thin saws a specialty. send your full address, plainly written, for price list and circular to emerson, smith & co., beaver falls, pa., successors to emerson, ford & co. * * * * * roots' patent portable forge. [illustration: adapted to every variety of work. ] the only forge with force blast blower. the only effective forge made. p.h. & f.m. roots, manuf's, connersville, ind. s.s. townsend, gen'l ag't, liberty st., new york * * * * * first premium ahead of all at centennial, hand and self-inking. [illustration: do your own printing the excelsior presses ] save money! do more advertising. $ press for cards, labels, envelopes, etc. large sizes for large work. _anybody_ can work them, have good pastime for spare hours, and can make money by taking in small jobs. boys have much fun and make money very fast at printing cards, etc., send two stamps for catalogue, to mfrs, kelsey & co. meriden, conn. * * * * * machinists' tools. new and improved patterns. send for new illustrated catalogue. lathes, planers, drills, &c. new haven manufacturing co., new haven, conn. * * * * * to appear end of february, the united states business directory for . this directory contains over , names of persons in all kinds of business. arranged alphabetically according to states, and classified according to business. it is a valuable aid to the merchant, manufacturer, and mechanic, for correspondence or the distribution of circulars. the edition of is the third year of issue, and has already received a largely increased patronage from the business public. price to parties who send their order before the book is issued, $ . . geo. de colange & co., publishers, bond st., new york. * * * * * hartford steam boiler inspection & insurance company. w.b. franklin, v. pres't j.m. allen, pres't j.b. pierce sec'y. * * * * * elocutionist's journal gives choicest standard and new pieces for professional and amateur readers and speakers, and interesting articles on appropriate subjects. just the thing wanted. cts. of any newsdealer or by mail. jesse haney & co., nassau street, new york. * * * * * noye's mill furnishing works are the largest in the united states. they make burr millstones, portable mills, smut machines, packers, mill picks, water wheels, pulleys and gearing, specially adapted to flour mills. send for catalogue. j.t. noye & son, buffalo, n.y. * * * * * [illustration: rock drilling machines and air compressors manufactured by burleigh rock drill co. send for pamphlet. fitchburg mass. ] * * * * * [illustration] niagara steam pump works. established . charles b. hardick, no. adams street, brooklyn, n.y. * * * * * non-combustible steam boiler and pipe covering with "air space" improvement. saves to per cent. chalmers spence co., foot e. th st. n.y.; n. d st., st. louis, mo. * * * * * the hoadley portable steam engine. with automatical cut-off regulator and balanced valve the best and most economical engine made _send for circular_ the j.c. hoadley co. lawrence, mass. state where you saw this * * * * * important for all corporations and manf'g concerns.--buerk's watchman's time detector, capable of accurately controlling the motion of a watchman or patrolman at the different stations of his beat. send for circular. j.e. buerk, p.o. box . boston, mass. n.b.--the suit against imhaeuser& co., of new york, was decided in my favor, june , . proceedings have been commenced against imhaeuser & co. for selling, contrary to the order of the court. persons using clocks infringing on my patent, will be dealt with according to law. * * * * * established . joseph c. todd, (formerly of todd & rafferty), engineer and machinist. flax, hemp, jute, rope, oakum, and bagging machinery, steam engines, boilers, etc. also agent for the celebrated and improved rawson & rittinger hoisting engine, i will furnish specifications and estimates for all kinds of machinery. send for descriptive circular and price. address j.c. todd, barclay st., new york, or paterson, n.j. * * * * * [illustration: patent cold rolled shafting. ] the fact that this shafting has per cent. greater strength, a finer finish, and is truer to gauge, than any other in use, renders it undoubtedly the most economical we are also the sole manufacturers of the celebrated collins' pat. coupling, and furnish pulleys, hangers, etc., of the most approved styles. price list mailed on application to jones & laughlins, try street, d and rd avenues, pittsburgh, pa. s. canal street, chicago, ill., and milwaukie, wis. stocks of this shafting in store and for sale by fuller. dana, & fitz, boston, mass. geo. place & co. chambers st., n.y. * * * * * a cyclopedia of mechanics and engineering, for sale. the few copies of the author's extra edition of prof. r.h. thurston's report on machinery and manufactures at the great international exhibition, , with an account of european manufacturing districts. the volume contains over pages, and contains wood-cuts and plates. please send orders for copies at once. price, $ . . f.t. thurston, civil and mechanical engineer. hoboken, n.j. * * * * * tube cleaners for cleaning boiler tubes. the national steel tube cleaner co. e. th st., n.y. * * * * * knowles steam pump works, & liberty st., new york. great reduction in prices. send for catalogue. the "knowles" has always been the best steam pump made. * * * * * [illustration: to inventors and manufacturers ] follows & bate, manchester, england, hardware and machinery merchants, are prepared to buy american goods for cash, and to act as sole wholesale agents. * * * * * punching presses drop hammers and dies, for working metals, &c. the stiles & parker press co., middletown, conn. * * * * * alcott lathes, for broom, rake and hoe handles. s.c. hills, chambers st., n.y. * * * * * machinery of improved styles for making shingles, heading and staves; also guage lathes for turning handles. sole makers of law's pat. shingle and heading sawing machine. address trevor & co., lockport, n.y. * * * * * chloride of calcium. for sale very cheap. ransome, bush street, san francisco, cal. * * * * * perfect newspaper file the koch patent file, for preserving newspapers, magazines, and pamphlets, has been recently improved and price reduced. subscribers to the scientific american and scientific american supplement can be supplied for the low price of $ . by mail, or $ . at the office of this paper. heavy board sides; inscription "scientific american," in gilt. necessary for every one who wishes to preserve the paper. address munn & co., publishers scientific american. * * * * * lecount's patent machinists' tools. reduced prices. set iron dogs, - to in., $ . " " " - to in., . " steel " - to in., . " " " - to in., . iron & steel clamps, die dogs, clamp dogs, vice clamps expanding mandrels, &c. send for latest price list to c.w. le count, south norwalk, conn. * * * * * best damper regulators and lever gauge cocks. murrill & keizer, holliday st., baltimore. * * * * * brayton ready motor it has no boiler, is safe, economical, started by any one in one minute, occupies small space, and gives an unsurpassed steady, reliable power. address penna ready motor co., n. th st philadelphia, pa. * * * * * the tanite co., stroudsburg, pa. emery wheels and grinders. geo. place, chambers st., new york agent. * * * * * bolt cutters schlenker's new machine revolving-die. send for catalogue, giving prices and full description. howard iron works, buffalo, n.y. * * * * * state, county and shop rights for sale of c. koons' patent rat trap; best out; caught one night. enclose stamp to owners and manufacturers, j.t. wilhide & bro., york road, carroll co., md. * * * * * $ to $ day at home. samples worth $ free. stinson & co., portland, me. * * * * * duc's improved patent elevator bucket, for brewers, flour mills, grain elevators, sugar refiners, &c. these buckets are made of the best charcoal stamping iron, and are warranted to outwear six of the "oldstyle buckets." the cost is about the same. address t.f. rowland, brooklyn, e.d., n.y. * * * * * $ watches. cheapest in the known world. _sample watch and outfit free to agents._ for terms address coulter & co. chicago. * * * * * bogardus' patent universal eccentric mills--for grinding bones, ores, sand, old crucibles, fire clay, guanos, oil cake, feed, corn, corn and cob, tobacco, snuff, sugar, salts, roots, spices, coffee, cocoanut, flaxseed, asbestos, mica, etc., and whatever cannot be ground by other mills. also for paints, printers' inks, paste blacking, etc. john w. thomson, successor to james bogardus, corner of white and elm sts. new york. * * * * * _working models_ and experimental machinery, metal or wood, made to order by j.f. werner, center st., n.y. * * * * * eagle foot lathes, [illustration: eagle foot lathe] with scroll and circular saw attachments, slide rest, tools, &c.; also small engine lathes, metal hand planers, &c. neatest designs, superior finish. low prices. our new catalogue describes these and every tool necessary for the amateur or artisan. send for it. wm. l. chase & co., & liberty st. new york. * * * * * pyrometers for showing heat of ovens, hot blast pipes, boiler flues, super-heated steam, oil stills, &c. henry w. bulkley. sole manufacturer, broadway, new york. * * * * * prospectus of the scientific american for , the most popular scientific paper in the world. ---- thirty-second year. ---- volume xxxvi.--new series. ---- the publishers of the scientific american beg to announce that on the sixth day of january, , a new volume was commenced. it will continue to be the aim of the publishers to render the contents of the new volume more attractive and useful than any of its predecessors. _to the mechanic and manufacturer._ no person engaged in any of the mechanical pursuits should think of doing without the scientific american. every number contains from six to ten engravings of new machines and inventions which cannot be found in any other publication. terms of subscription. one copy of the scientific american will be sent for _one year_, numbers, postage prepaid, to any subscriber in the united states or canada, on receipt of _three dollars and twenty cents_ by the publishers. _one extra copy_ of the scientific american will be supplied gratis _for every club of five subscribers_ at $ . each; or six copies for $ . without extra copy. postage free. the scientific american supplement. a weekly paper, uniform in size with the scientific american, but a distinct publication. it contains working drawings of engineering works, and elaborate treatises on every branch of science and mechanics, by eminent writers, at home and abroad. an illustrated cover protects the handsomely printed sheets. price, $ . per annum. single copies cents. _one copy of the_ scientific american _and one copy of the_ scientific american supplement will be sent for one year, postage prepaid, to any subscriber in the united states or canada, on receipt of _seven dollars_ by the publishers. the safest way to remit is by postal-order, draft, or express. money carefully placed inside of envelopes, securely sealed, and carefully addressed, seldom goes astray; but it is at the sender's risk. address all letters and make all orders, drafts, etc., payable to munn & co., park row, new york. * * * * * the "scientific american" is printed with chas. eneu johnson & co.'s ink. tenth and lombard sts., philadelphia, and gold st., new york. [illustration] scientific american a weekly journal of practical information, art, science, mechanics, chemistry, and manufactures. new york, march , . vol. xxiv.--no. . [new series.] $ per annum [in advance.] * * * * * scientific american. munn & co., editors and proprietors. published weekly at no. park row (park building), new york. o. d. munn. s. h. wales. a. e. beach. vol. xxiv., no. ... [new series.] _twenty-sixth year_ new york, saturday, march , . * * * * * contents: (illustrated articles are marked with an asterisk.) *knots and splices influence of cold on iron and steel. oak graining in oil colors knots and splices (explanation) hartford steam boiler and insurance co.'s report *improved spiral spring for railway carriages *portable writing and copying case how walking-sticks are made flowering of the victoria regia jute ventilation of the liverpool tunnel *impregnating wood with tar, etc. *boardman's combined tool *belt tightener some things i don't want in the building trades *action of the reciprocating parts of steam engines *answer to practical problem reciprocating parts of steam engines test for white lead how to build a chimney crystallized honey rambles for relics.--no. silk culture *universal boring machine *combined trunk and rocking-chair cosmetics *smith's infant dining-chair the medicines of the ancients *barnes ventilator for mattresses exhibition of the national photographic association a scientific and technical awakening the sherman process rubber tires for traction engines central shaft of the hoosac tunnel a museum of art and natural history report of judges, american institute fair. --the allen engine lyceum of natural history warming and ventilating railroad cars the mineral resources of missouri scientific intelligence american institute of mining engineers consumption of sugar, coffee, and tea unpleasant discovery in the patent office substitute for albumen in photography (omitted) louisiana state fair test for purity of water new books and publications business and personal answers to correspondents applications for the extension of patents recent american and foreign patents queries inventions patented in england by americans list of patents * * * * * the influence of intense cold on steel and iron. [condensed from nature.] there has recently been a most interesting discussion at the literary and philosophical society, manchester, on the above subject. the paper which gave rise to the discussion was by mr. brockbank, who detailed many experiments, and ended by stating his opinion that iron does become much weaker, both in its cast and wrought states, under the influence of low temperature; but mr. brockbank's paper was immediately followed by others by sir w. fairbairn, dr. joule, and mr. spence, which at once put an entirely new complexion on the matter. dr. joule says: "as is usual in a severe frost, we have recently heard of many severe accidents consequent upon the fracture of the tires of the wheels of railway carriages. the common-sense explanation of these accidents is, that the ground being harder than usual, the metal with which it is brought into contact is more severely tried than in ordinary circumstances. in order apparently to excuse certain railway companies, a pretence has been set up that iron and steel become brittle at a low temperature. this pretence, although put forth in defiance, not only of all we know, of the properties of materials, but also of the experience of everyday life, has yet obtained the credence of so many people that i thought it would be useful to make the following simple experiments: " st. a freezing mixture of salt and snow was placed on a table. wires of steel and of iron were stretched, so that a part of them was in contact with the freezing mixture and another part out of it. in every case i tried the wire broke outside of the mixture, showing that it was weaker at ° f., than at about ° f. " d. i took twelve darning needles of good quality, in. long, / in. thick. the ends of these were placed against steel props, - / in. asunder. in making an experiment, a wire was fastened to the middle of a needle, the other end being attached to a spring weighing-machine. this was then pulled until the needle gave way. six of the needles, taken at random, were tried at a temperature of ° f., and the remaining six in a freezing mixture which brought down their temperature to ° f. the results were as follow:-- warm needles. cold needles. ounces broke ounces broke " " " " " " " " " " " bent " " " broke " bent " " --- --- average, - / average, - / "i did not notice any perceptible difference in the perfection of elasticity in the two sets of needles. the result, as far as it goes, is in favor of the cold metal. " d. the above are doubtless decisive of the question at issue. but as it might be alleged that the violence to which a railway wheel is subjected is more akin to a blow than a steady pull; and as, moreover, the pretended brittleness is attributed more to cast iron than any other description of the metal, i have made yet another kind of experiment. i got a quantity of cast iron garden nails, an inch and a quarter long and / in. thick in the middle. these i weighed, and selected such as were nearly of the same weight. i then arranged matters so that by removing a prop i could cause the blunt edge of a steel chisel weighted to lb. oz., to fall from a given height upon the middle of the nail as it was supported from each end, - / in. asunder. in order to secure the absolute fairness of the trials, the nails were taken at random, and an experiment with a cold nail was always alternated with one at the ordinary temperature. the nails to be cooled were placed in a mixture of salt and snow, from which they were removed and struck with the hammer in less than "." the collective result of the experiments, the details of which need not be given, was that cold nails broke and warm ones. dr. joule adds, "the experiments of lavoisier and laplace, of smeaton, of dulong and petit, and of troughton, conspire in giving a less expansion by heat to steel than iron, especially if the former be in an untempered state; but this, would in certain limits have the effect of strengthening rather than of weakening an iron wheel with a tire of steel. "the general conclusion is this: frost does _not_ make either iron (cast or wrought), or steel, brittle. mr. spence, in his experiments, decided on having some lengths of cast iron made of a uniform thickness of ½ in. square, from the same metal and the same mould. he writes:--"two of the four castings i got seemed to be good ones, and i got the surface taken off, and made them as regular a thickness as was practicable. "i then fixed two knife-edged wedges upon the surface of a plank, at exactly nine inches distance from each other, with an opening in the plank in the intervening space, the bar being laid across the wedges, a knife-edged hook was hung in the middle of the suspended piece of the bar, and to the hook was hung a large scale on which to place weights. "the bar was tried first at a temperature of ° f.; to find the breaking weight i placed lb. weights one after another on the scale, and when the ninth was put on the bar snapped. this was the only unsatisfactory experiment, as or lb. might have done it, but i include it among others. i now adopted another precaution, by placing the one end of the plank on a fixed point and the other end on to a screw-jack, by raising which i could, without any vibration, bring the weight to bear upon the bar. by this means, small weights up to lb. could be put on while hanging, but when these had to be taken off and a large weight put on, the scale was lowered to the rest, and again raised after the change was made. i may here state that a curious circumstance occurred twice, which seems to indicate that mere raising of the weight, without the slightest apparent vibration, was equal in effect to an additional weight. ¾ cwts. were on the scale, a lb. weight was added, then lb., then lb., lb., lb., and lb., making cwts. and lb. this was allowed to act for from one to two minutes, and then lowered to take off the small weights, which were replaced by a lb. with the intention of adding small weights when suspended; the whole was then raised so imperceptibly by the screw, that the only way of ascertaining that it was suspended, was by looking under the scale to see that it was clear of the rest. as soon as it was half-an-inch clear it snapped, thus breaking at once with one pound less than it resisted for nearly two minutes. "six experiments were carefully conducted at ° f., the parts of the bars being selected so as to give to each set of experiments similar portions of both bars; the results are marked on the pieces. my assistant now prepared a refrigerating mixture which stood at zero, the bars were immersed for some time in this, and we prepared for the breaking trials to be made as quickly as could be, consistently with accuracy; and to secure the low temperature, each bar, on being placed in the machine, had its surface at top covered with the freezing mixture. the bars at zero broke with more regularity than at °, but instead of the results confirming the general impression as to cold rendering iron more brittle, they are calculated to substantiate an exactly opposite idea, namely, that reduction of temperature, _cæteris paribus_, increases the strength of cast iron. the only doubtful experiment of the whole twelve is the first, and as it stands much the highest, the probability is that it should be lower; yet, even taking it as it stands, the average of the six experiments at ° f., gives cwt. lb. as the breaking weight of the bar at that temperature, while the average of the six experiments at zero gives cwt lb. as the breaking weight of the bar at zero, being an increase of strength, from the reduction of temperature, equal to . per cent." sir w. fairbairn states: "it has been asserted, in evidence given at the coroner's inquest, in a recent railway accident, that the breaking of the steel tire was occasioned by the intensity of the frost, which is supposed to have rendered the metal, of which this particular tire was composed, brittle. this is the opinion of most persons, but judging from my own experience such is not the fact. some years since i endeavored to settle this question by a long and careful series of experiments on wrought iron, from which it was proved that the resistance to a tensile chain was as great at the temperature of zero as it was at ° or upwards, until it attained a scarcely visible red heat." the immense number of purposes to which both iron and steel are applied, and the changes of temperature to which they are exposed, renders the inquiry not only interesting in a scientific point of view, but absolutely necessary to a knowledge of their security under the various influences of those changes. it was for these reasons that the experiments in question were undertaken, and the summary of results is sufficiently conclusive to show that changes of temperature are not always the cause of failure. sir w. fairbairn adds: "the danger arising from broken tires does not, according to my opinion, arise so much from changes of temperature as from the practice of heating them to a dull red heat, and shrinking them on to the rim of the wheels. this, i believe, is the general practice, and the unequal, and in some cases, the severe strains to which they are subject, has a direct tendency to break the tires." * * * * * oak graining in oil colors. condensed from the building news. there is a charm and feeling about work executed by the hand, which gives it a value no mere machine work can possess. machine work, from its very nature, necessitates a repetition of pattern, which cannot be avoided. hand-work, on the contrary, can imitate every variety, and follow nature so closely that no two pieces need be alike. there is also in hand-work a wide scope for the inventive faculty and the exercise of good taste (both in form and color) and skillful workmanship. as a rule, strong contrasts between the ground and the graining color should be avoided. the figure and grain should of course be seen clearly, but only so clearly as to be distinct, without interfering with the general and uniform quietness of tone necessary to fulfil the conditions required by the laws of harmony and good taste. violent contrasts and gaudy coloring are always vulgar, brilliancy and richness of color are not necessarily vulgar; it is the absence of the guiding power of knowledge and pure taste in their arrangement which degrades them to the rank of vulgarity. we have before spoken of the importance of good combing, and of the various kinds of combs used; we now proceed to describe how the work is done. the graining color is brushed over the work, in the ordinary manner, with a pound-brush, care being taken not to put too much color on, or else it is very liable to be dirty. a dry duster is now used to stipple with, which, if properly done, will distribute the color evenly; it is now ready for combing. in the real oak it will be found, as a rule, that the grain is invariably coarser on one side of the panel than on the other; this arises from the very nature of the growth of the tree; it is, therefore, well to imitate this pattern, and in order to do so we take first a medium or coarse cut gutta-percha comb, and draw it down one side of the panel; then use a finer one to complete it. this comb will leave the marks of the grain in clear unbroken lines from top to bottom of the panel. we now take a fine steel comb and go over the whole of the previous combing, moving it in a slanting or diagonal direction across the previous grain, or with a quick and short wavy motion or curl; both the former and the latter motion will break up the long lines, left by the gutta-percha comb, into short bits, which of course represent the pores or grains of the real wood. there are several other motions of the comb having the same end in view; and by using the gutta-percha or cork combs, in conjunction with the fine steel, an infinite variety of grain may be produced. steel combs, with one or more folds of thin rag placed over the ends of the teeth are a style of comb which has nothing to recommend it. a natural variation in the grain may be produced by one comb alone, according to the manner in which it is held. for instance, if we take a coarse or broad-toothed gutta-percha comb, and commence at the top of a panel, with the comb, placed at its full width: if drawn down in this position it will leave a grain of the same width as the width of the teeth: but if we start with the full width, and gradually turn the comb or slightly incline it to one side--that is to say, on its edge, we thereby graduate the grain from coarse to fine at pleasure, and by holding the comb at a certain inclination we may actually make very fine the coarse comb. a very important point is the formation of the joints in the wood, as much of the effect of otherwise good work is lost in consequence of neglect in this respect. in looking at a real oak door, the joints of the stiles and rails are clearly and sharply defined, not by any defect of workmanship, but by the difference in the run of the grain, the stiles being perpendicular, and the rails horizontal. the rails being cut sharp off by the stiles, show a perfectly straight line. the light also acts differently upon the two, simply because the grain or fibre of the wood is exposed to its influence under different aspects. this also tends to produce a difference in the depth of the color of rails and stiles, and panels also. it will be evident that no imitations can be considered really good except they include these seemingly unimportant points. it is a common practice for grainers to imitate a broad piece of heart or sap of oak, upon the back rail of almost every door they do, and many of them are not even content with that, but daub the stiles over from top to bottom with it also. there is nothing so vulgar or in such bad taste. it should only be done upon those parts of the work on which it would appear on a real oak door, namely, on the edges of the doors and on mouldings. there is a vulgar pretentiousness about what we may call the sappy style of work which is very undesirable. the figures cross the grain more or less abruptly and of course are of different shapes, sizes, and forms, a knowledge of which can only be acquired by study of the real wood. the figure may be wiped out with a piece of soft rag, held tight over the thumb nail. this should have two or three folds over the nail, the superfluous rag being held by the other hand to prevent it hanging down and smearing the grain; and every time a figure is wiped, the rag should be moved slightly, so that the same part of the rag will not be used twice, thus insuring clean work. it will often happen that the thumb-nail will get broken, or is too weak to stand the work; in these cases, or, in fact, in any case, a good substitute or artificial thumb-nail may be made of gutta-percha, thus: a piece of thin sheet gutta-percha is put into warm water, and, while soft, is wrapped around the end of the thumb up to the first joint. it is then pressed with the hand, so as to fit and take the shape of the thumb and nail. this cannot be done at one heating, but will have to be put into the hot water again, and the end pinched and squeezed into form to the shape of the nail, and to fit easily upon the thumb. when this gets hard, it may be trimmed into perfect form with a penknife. this artificial nail will answer the purpose admirably if properly made; and even when the natural nail is good, the gutta-percha will serve to save it from injury. good figuring may also be done by using the blank end of the steel comb with a rag folded over its edge. we have also used a piece of gutta-percha to take out the lights. this should be square-ended, about one inch wide, and three or four inches long, and will do successful work of a certain class, but not of the best. many grainers use a piece of thin horn, in shape something like a spatula, about three or four inches long and three quarters of an inch wide, with rounded ends, and quite flexible. with this tool the figure is cut or scooped out--a sort of quick, side-long motion, very difficult to describe, and requiring a very considerable amount of practice before it can be worked with any success. there is, however, the same objection to this tool as may be urged against the gutta-percha for figuring, namely, that neither of them take the color clean away, but leave an accumulation of color on the edge of the figure, which is fatal to good work; and therefore we cannot honestly recommend the use of any method but the wiping out with the thumb-nail or its substitute. when the figure is wiped out it will require to be softened. by softening, we mean the imitation of those half shades seen upon and about the figures in the real wood. between and around the lights or figure in oak, there is always a lighter tint of color; this is imitated by doubling a piece of rag into a small roll, and with the side of this the grain is partially wiped away, but not to the extent of taking off the whole of the grain. a recent but most admirable system of graining oak, by means of over-combing, is worked exactly the reverse of any of the foregoing methods; that is to say, the figure is first wiped out, and the combing or grain is done afterwards, when the graining color is dry, in this wise: the graining color is mixed somewhat thinner than for ordinary graining, and is brushed over the work sparingly, leaving it just sufficiently strong to show a clear distinction between the ground and the color. the light or figure is then softened by drawing the end of a flat hog-hair fitch, or a small thin mottler, across each figure, and slightly softening with the badger-hair softener. the figure is broken up a little with fine lines across it in parts, such as may be seen in the real wood; but previous to wiping out the figure, streaks of light should be wiped out and softened on one side of the panel or across the stiles, in imitation of the reflective lights seen in oak. the color should also be partially wiped off the rails or stiles at their junction; this tends to define the joint. the color is now let to dry hard, when it will be ready for over-combing--that is, combing or graining over the figure (hence its name), and this will have to be done somewhat differently to the ordinary combing. as thus: the color is rubbed in as before, and combed solely with the gutta-percha combs, but these are specially cut for the purpose; they are best about in. wide. the first must be cut with teeth about three-sixteenths of an inch in width, the next one-eighth, and the third about one-sixteenth. the broad-toothed comb is first used, and must be drawn down the panel, with a wavy motion, in short or long curls; either will answer our purpose now. the next size of comb is then drawn straight down--the straighter the better. this has the effect of breaking the wavy combing into short and long straight bits, similar to the pores or grain of the real wood. both the first and second combing may be varied by holding the comb in a slanting direction, and may be fine or coarse, according to the width of the combs used; now take a soft rag folded, and with this partially clear off the grain which runs over the figure, leaving only a sufficient quantity crossing the light or figure, to be just distinguished, exactly as it appears upon the figure in real oak. the grain is also wiped off in parts on the plain spaces between the figure, in order to break it up and take away any formality. if this method be well and probably done, a thoroughly deceptive imitation may be produced; and except this end be kept in view, no really good work will result. * * * * * knots and splices. [_see engraving on first page._] . turn used in making up ropes. . end tapered for the purpose of passing it readily through a loop. to make this, we unlay the rope for the necessary length, reducing a rope diminishing in diameter towards the end, which is finished by interlacing the ends without cutting them, as it would weaken the work; it is lastly "whipped" with small twine. . tapered end, covered with interlaced cordage for the purpose of making it stronger. this is done with very small twine attached at one end to the small eye, and at the other to the strands of the rope, thus making a strong "webbing" around the end. . double turn used for making rope. . eye splice. the strands of the cable are brought back over themselves, and interlaced with their original turns, as in a splice. . tie for the end of a four-strand rope. . the same completed; the strands are tied together, forming loops, laying one over the other. . commencement for making the end by interlacing the strands. . interlacing complete, but not fastened. and . shell in two views used in no. , showing the disposition of it at the throat. this joining is advantageous, as it does not strain the cords, and it prevents them from cutting each other; so that the rings pass one into the other and are joined outside the intermediate shell. . interlacing in two directions. . mode of finishing the end by several turns of the twine continued over the cable. . interlacing commenced, in one direction. . interlacing finished, the ends being worked under the strands, as in a splice. . pigtail commenced. . interlacing fastened. . pigtail with the strands taut. . dead eye, shown in two views. . pigtail finished. we pass the ends of the strands, one under the other, in the same way as if we were making a pudding splice: thus bringing it in a line with the rope, to which it is seized fast, and the ends cut off. . scull pigtail; instead of holding the ends by a tie, we interlace them again, as in no. , the one under the other. . pigtail, or "lark's nest." we make this to the "pennant" of a cable, which has several strands, by taking the requisite number of turns over the pudding, in such a manner that the strands shall lay under each other. this "pigtail" forms a knot at the end of the rope. it thus draws together two ropes, as shown in no. , forming a "shroud" knot. in these two pigtails, the strands are crossed before finishing the ends, so that the button, a, is made with the strands, a, and b, with those of the rope, b. . slip clinch to sailors' knot. . slip clinch, secured. . ordinary knot upon a double rope. . bowline knot for a man to sit in at his work. . called a "short splice," as it is not of great length, and besides, can be made quickly. . long splice. this extends from a to b. we unlay the strands of each of the ropes we intend to join, for about half the length that the splice will be, putting each strand of the one between two strands of the other. . simple fastening on a rope. . a "shroud" knot. . the ends of the rope are prepared for making the splice (no. ) in the same manner as for the "shroud" knot in no. . when the strands are untwisted, we put the ends of two cords together as close as possible, and place the ends of the one between the strands of the other, above and below alternately, so as to interlace them as in no. . this splice is not, however, very strong, and is only used when there is not time to make a long splice, which is much the best. and . marline spikes. tools made of wood or iron, used to open out a rope to pass the strands of another through it. . shows strands arranged as described in no. . . fastening when a lever is used, and is employed when hauling upon large ropes, where the strength of several men are necessary. . a "pudding splice." this is commenced, like the others, by placing the rope end to end, the turns of the one being passed between those of the other; having first swelled out the yarns by a "rat's-tail," we put them, two by two, one over the other, twisting them tightly, and opening a way for them with the marlinspike. the inconvenience of this splice is, that it is larger in diameter than the rope itself; but when made sufficiently long, by gradually reducing the size of the strands, it has great strength. . this shows two strands, a and b, of the ropes, a b, knotted together, being drawn as tight as possible; we unlay the strand, a', of the rope, a, for half the length of the splice, and twist the strand, b', of the rope, b, strongly in its place, tying a' and b' together tightly. the same process is again gone through on the rope, b, the strand, a", of the rope, a, being knotted to the strand, b", of the rope, b. when all the strands are thus knotted together, we interlace them with the strands of the cable. thus the strands, a a' a", are interlocked by being passed alternately above and below the turns of the cord, b, the ends being also sometimes "whipped." in the same manner the strands, b b' b", pass alternately over and under the strands of the rope, a, and are in like manner "whipped." it is important that the several interlacings and knots should not meet at one point; we reduce the size of the strands towards the end, so that they loose themselves in the body of the splice, cutting off such parts as may project. this splice is employed for joining the ends of a rope when a chafed part has been cut out, and is quite as strong as the rope itself. . belaying-pin opened to serve as a button; these are used where it is necessary to stop or check velocity. . chain knot, or fastening. . variable or regulating lashing. by laying the piece, a f, horizontally, it can be slipped along the rope, b; by raising or lowering this, we shall raise or depress the weight, c, the cord, b, running over the two pulleys, d, from the piece, a f, in the direction shown in the figure. the friction of the cord, b, passing through the hole, e, sufficiently fixes the piece, a f, and holds the weight, c, securely. . cleet, with three ties. . cleet, showing the mode of belaying the cord. . the piece, a f, of no. . . fair leader. . cleet to be fixed to a stay. . loop for slipping other lines. . a "bend" which is only used for fear of the stoppers snapping. . bastard loop, made on the end of the rope, and whipped with yarns. . tie to pins: a, the pin; b, small cords fixed by a cross tie. . cleet, fixed to the "rail," either with screws or nails, to which the lines are belayed. . waterman's knot. . fair leader. . tie, or bend to pier. . simple fastening to tie. . fastening by a loop. this can be tied or untied without loosening the loop itself. it is made by following, towards the longer loop, the direction as numbered , , , , , and is terminated by the loop, , , , finally passing it over the head of the post, a. this knot holds itself, the turns being in opposite directions. to untie it, we slack the turns of the cable sufficiently to again pass the loop, , , , over the post, a, and turn the ends in the contrary direction to that in which they were made (as , , , , ). . iron "shell," in two views. and . "wedding" knots; a b, eyelets; c d, the join; e, the fastening. . lark's-head fastening to running knot. . a round turn; the cord, a, is passed through the bight of the cord, b, over the button, c, where it is secured by an ordinary knot. . belaying-pin splice. the cord, b, "stops" the pin, e, its end being spliced upon itself, and "served" with yarn; this rope, with its pin, is passed through the spliced eye, f of the line, g. . round button. . joint by a spherical shell, each loop, a and b, being made by ties and splices, and surrounding the shell, c. . belaying-pin, shown separately, before being stoppered. . fastening to shears. . square mooring. when the cable is round the post, a, and the piece, c, without being crossed, it lays in the section , , , , , , , and the end is fastened by tying. . wooden shell in section. . crossed fastening. the turns of the cable, passing in front of the post, b, are crossed at the back of c, in the direction , , , , , , , , the end, , being secured to the cable. . wooden shell. . double-chain fastening. . lashing for "ram" block, or "dead-eye." the ram blocks, a and b, are strapped by the cords, e, which hold them; the small lanyards, d, pass through the holes to make the connection, and as they are tightened give the requisite tension to the cordage; the ends are fastened to the main rope. usually one of these dead-eyes is held by an iron strap to the point where it is required to fix and strain the cordage, which is ordinarily a shroud. . chain fastening. '. simple band, showing the upper side. '. the same, showing the under side and the knot. '. tie, with crossed ends, commenced; a turn is taken under the strands, to hold the ends of the cord. '. the same, completed. '. bend with crossed strands, commenced, the one end being looped over the other. '. the same, completed. '. necklace tie, seen on the upper side. '. the same, seen underneath. the greater the strain on the cords, the tighter the knot becomes. ' and ' are similar splices to ' and ' with slight modifications. ' shows the commencement of ', the legs in elevation; ' being a front view. an ordinary band, made by several turns of a small rope, is lapped round them and hauled taut, and then interlaced at the ends. this done, the legs are shifted into the shape of a st. andrew's cross. thus the lashing is tightened, and, for further security, we pass the line several times over the tie and between the spars, knotting the ends. '. portuguese knot. this is a lashing for shear legs, and must be tight enough to prevent the spars slipping on each other; the crossing of the two legs gives a means of securing the knot. '. for binding timbers; a, knot commenced. take several turns round the timbers, and fasten the ends by passing them under the turns; b, knot completed. the end of a round stick, m n, termed a packing stick, should be passed under the knob, the cord being slack enough to allow of this. by turning the stick, the turns can be tightened to any extent; when tight, we fasten the longer arm of the lever to some fixed point, by a rope, p q, so that it cannot fly back. care must be taken not to turn the stick too far, or the rope may be broken. as the timber dries and shrinks, the lever may be used to make all taut again. * * * * * the hartford steam boiler inspection and insurance company. the hartford steam boiler inspection and insurance company makes the following report of its inspections in january, : during the month, there were visits of inspection made, and , boilers examined-- externally and internally, while have been tested by hydraulic pressure. number of defects in all discovered, , of which were regarded as dangerous. these defects were as follows: furnaces out of shape, -- dangerous; fractures, -- dangerous; burned plates, -- dangerous; blistered plates, -- dangerous; cases of sediment and deposit, -- dangerous; cases of incrustation and scale, -- dangerous. to show how little attention is paid to the internal condition of boilers by incompetent engineers, we copy the following from a letter of one of our inspectors: "in one tubular boiler i found sediment in the back end, eight inches deep, and extending forward more than four feet. it seemed to be an accumulation of fine scale cemented together, so that it was necessary to break it up with a hammer and chisel before it could be removed. the engineer said _he had cleaned the boilers only three days before_, and objected to my making another examination. this is one of the many cases we find, where the proprietor trusts everything about his boilers to his engineer, supposing him to be reliable." with such accumulation of sediment and deposit, is it any wonder that sheets are burned? a careful engineer will understand, if the feed water be impure, that he must blow down two or three inches every day, or oftener, that the sediment may be removed as it accumulates, and then an internal examination once in two weeks, or once a month, will insure a clean boiler. cases of external corrosion, -- dangerous; cases of internal corrosion, -- dangerous; cases of internal grooving, -- dangerous; water gages out of order, ; blow-out apparatus out of order, -- dangerous; safety valves overloaded, -- dangerous; pressure gages out of order, -- dangerous, varying from - to + pounds. (we have found several gages entirely ruined from being frozen). boilers without gages, ; cases of deficiency of water, -- dangerous; broken braces and stays, -- dangerous; boilers condemned, --both dangerous. two engineers were found drunk on duty, and promptly discharged. there were serious explosions during the month, by which persons were killed, and wounded. eighty-seven of the killed were passengers on the ill-fated steamer _h.r. arthur_, on the mississippi river. many were drowned, and some burned, but the origin of the calamity was the bad quality of the boilers, which a careless management was unable to detect. the upper and fore part of the boat was blown away by the exploded boilers, and, to add to the horror, what remained took fire. none of these exploded boilers were under the care of this company. * * * * * five ore-roasting furnaces are in full blast in nevada. * * * * * improved compound spiral car spring for railway carriages. our engravings illustrate an improved compound car-spring, which appears to possess all the requisites of a first-class spring, combining in its construction extreme simplicity with great strength, and a feature whereby the power of the spring increases with increase of the load, and _vice versâ_, so that its flexibility remains nearly constant for all loads. fig. is a perspective view of this spring, with a portion of the side of the case broken out to show the interior arrangement of the spiral springs. fig. is a section of the compressing plate. fig. is a plan view, showing the arrangement of the tubes which enclose the springs. [illustration: pott's' spiral car spring for railway carriages. _fig. fig. fig. _] the case is cast in two pieces. its vertical wall is cast in a single piece, and has at the top a flange or bead extending inwardly, against which the compressing plate abuts when the spring is not compressed, as shown in fig. . a bottom plate completes the case. the spiral components of the spring are inclosed in tubes, as shown in figs. and . it is not deemed essential that these tubes should be seamless, or that their edges, brought together in bending, should be soldered, brazed, or welded. they act merely as guides to compel the component springs to expand or contract in vertical lines, and need only be strong enough for that purpose. the compressing plate is formed with concentric steps or ledges, as shown in fig. , so that with light loads, only a portion of the component spirals act. with a heavier load a new series of spirals is brought into action, and so on, till the spring is loaded to its full capacity. this feature is novel, and as important as novel, as it gives the spring a far more easy and flexible carriage, with light loads, than would be the case if all the spirals were permitted to act. in putting the spring together, the vertical part of the case is inverted. the compressing plate is then placed within the case, resting upon the inner flange of the case above described. the tubes with their inclosed springs are then arranged in position, as shown in the plan view, fig. . the bottom plate of the case is then placed in position, and held to its place by lugs and rivets, as shown in fig. ; the spring is then ready for use. the employment of tubes in the manner described, enables springs of the greatest practical length to be used, without the sectional or division plates met with in other spiral car springs. a greater and easier movement is therefore obtained. these springs can, it is claimed, compete in price with any spring in market, and are guaranteed by the manufacturers. patented through the scientific american patent agency, december , , by albert potts, whom address for further information, no. north third street, philadelphia, pa. * * * * * portable writing and copying case. this device is the invention of a. g. buzby, of philadelphia, pa. it is a combined writing and copying case. besides the usual recesses or chambers for pen, ink, paper, etc., it is provided with a book of copying paper, in which copies of important letters may be made, by damping the letters in the usual way, and pressing them between the leaves of the copying book; or the transfer paper may be used, so that the letter will be copied as it is written, if preferred. [illustration] * * * * * how walking sticks are made. sticks are manufactured both from large timber of from two to six feet girth, and from small underwood of about the thickness of a man's thumb. the timber, which is chiefly beech, is first sawed into battens of about three feet in length and as many inches in width; and from each of these battens two square sticks, with square heads are afterwards cut in opposite directions, so that the middle portion is waste wood. the corners of each are afterwards rounded off by a planing process called "trapping," and the square head is reduced, by a small saw, to a curve or rectangular bend, so as to form a handle. when the sticks are brought in this way to the exact size and pattern, they are polished with great care, are finely varnished, and packed in boxes or bundles for the market. many sawn sticks, however, are supplied with bone and horn handles, which are fastened on with glue; and then of course there is less wood waste, as a larger number of them may be cut from one batten. a very different process takes place in the manufacture of sticks from small underwood, in which there is no sawing required. the rough unfashioned sticks, which are generally of hazel, ash, oak and thorn, are cut with a bill in the same way as kidney bean sticks, and are brought to the factory in large bavins or bundles, piled on a timber tug. there must of course, be some little care in their selection, yet it is evident that the woodmen are not very particular on this score, for they have in general an ungainly appearance; and many are so crooked and rough, that no drover or country boy would think it worth while to polish the like of them with his knife. having arrived at this place, however, their numerous excrescences are soon pruned away, and their ugliness converted into elegance. when sufficiently seasoned and fit for working, they are first laid to soak in wet sand, and rendered more tough and pliable; a workman then takes them one by one, and securing them with an iron stock, bends them skillfully this way and that, so as to bring out their natural crooks, and render them at last all straight even rods. if they are not required to be knotted, they next go to the "trapper," who puts them through a kind of circular plane, which takes off knots, and renders them uniformly smooth and round. the most important process of all is that of giving them their elegantly curved handles, for which purpose they are passed over to the "crooker." every child knows that if we bend a tough stick moderately when the pressure is discontinued, it will soon fly back, more or less, to its former position; and if we bend it very much, it will break. now the crooker professes to accomplish the miracle of bending a stick as it might be an iron wire, so that it shall neither break nor "backen." to prevent the breaking, the wood is rendered pliant by further soaking in wet sand; and a flexible band of metal is clamped down firmly to that portion of the stick that will form the outside of the curve; the top end is then fitted into a grooved iron shoulder which determines the size of the crook, the other end being brought round so as to point in the opposite direction; the metal band during this process binding with increasing tightness against the stretching fibers of the wood, so that they cannot snap or give way under the strain. the crook having been made, the next thing is to fix it, or remove from the fibers the reaction of elasticity, which would otherwise, on the cessation of the bending force, cause it to backen more or less, and undo the work. in the old process of crooking by steam, as timber bending is effected, the stick was merely left till it was cold to acquire a permanent set; but in the new process, a more permanent set is given by turning the handle about briskly over a jet of gas. the sticks being now fashioned, it only remains to polish and stain or varnish them; and they are sometimes scorched or burned brown, and carved with foliage, animal heads and other devices.--_chambers' journal_. * * * * * flowering of the victoria regia in the open air.--joseph mager, esq., has succeeded in flowering the victoria lily, in his pond in england. the pond is perfectly open, but the water is heated by hot water pipes coming from a boiler near the pond, carefully concealed. the seeds of the victoria were planted in may last, and the first flower was produced sept. th. afterwards seven other flowers opened. the plant has eight leaves, of which the largest is five feet two inches in diameter. mr. mager has also succeeded in flowering a large number of other tropical lilies in his pond. * * * * * jute, a material largely used in combination with hemp, for making cordage, sacking, mats, and carpets, is produced in india to the extent of , tuns per annum. the scarcity of fuel prevents its manufacture on the spot, except by the rudest and most primitive means, so that the bulk of the growth is sent to great britain. * * * * * ventilation of the liverpool tunnel. this tunnel, which forms an ascending incline of a mile and a quarter length from the terminal station in lime-street london and n. w. railroad, was worked until recently by a rope and stationary engine, to avoid fouling the air of the tunnel by the passage of locomotives; but the increase of the traffic having necessitated the abandonment of the rope and the substitution of locomotives for bringing the trains up through the tunnel, it became requisite to provide some efficient means of ventilation for clearing the tunnel speedily of the smoke and steam after the passage of each train. a large exhausting fan has been designed by mr. john ramsbottom for this purpose, which works in a chamber situated near the middle of the length of the tunnel, and draws the air in from the tunnel, through a cross drift; discharging it up a tapering chimney that extends to a considerable hight above the surface of the ground over the tunnel. the fan is about thirty feet diameter, and is made with straight radial vanes; it revolves on a horizontal shaft at a speed of about forty-five revolutions per minute, within a brick casing, built concentric with the fan for the first half of the circumference, and afterwards expanding gradually for discharging into the base of the chimney, the air from the tunnel being drawn in at the center of the fan at each side, and discharged from the circumference of the fan by the revolution of the vanes. the engine driving the fan is started by telegraph signal at each departure of a train from the terminal station, and the fan is kept running until the discharge from it becomes quite clear, showing that no steam or smoke remains in the tunnel; this is usually the case in about eight minutes after the time of the train entering the lower end of the tunnel, the passage of the train through the tunnel occupying about three minutes. the fan draws air in at both ends of the tunnel simultaneously, and begins to clear the lower end immediately upon the train entering; the clearing of the upper end commences as soon as the train has passed out of the tunnel, and as the fan is situated nearer the upper end of the tunnel than the lower, the clearing of both lengths is completed almost simultaneously. the fan is so constructed as to allow an uninterrupted passage through it, for the air, whilst the fan is standing still; and the natural ventilation thus obtained by means of the large chimney is found sufficient for clearing the tunnel during the night and some portion of the day, without the fan being worked at those times. this natural ventilation is aided by the engine exhaust and the boiler discharging into the chimney. the fan has now been in regular operation for three-quarters of a year, and has been found completely successful. * * * * * impregnating wood with tar or other preserving material. the preservation of wood is a problem which is attracting increased attention, as year by year diminishes the material supply of timber, and consequently gradually increases its price. among other methods employed, the impregnation of wood by the vapors of tar, creosote, petroleum, etc., has been tried, and one of the practical difficulties met with has been the obtaining of suitable apparatus for the purpose. [illustration] the engraving annexed is an invention intended to supply this want. the wood is inclosed, in a tank kept hot by a steam jacket which surrounds it, as shown. a boiler at one end is used to heat the substance with which it is desired to impregnate the wood. an air pump is also employed to remove the steam, generated in the heated timber, and the air from the tank. the pores of the wood being thus rendered vacuous, the hot liquid or vapors from the heating tank readily penetrate the entire substance, and thoroughly impregnate it. this apparatus is the invention of george pustkuchen, of hoboken, n. j. * * * * * boardman's combined tool. this tool, of which our engraving is a good representation, comprises a screw wrench, a pipe wrench, a hammer, a nail claw, a screw-driver, and a bit handle, or socket wrench. the bit handle is the entire tool, the square socket or opening being made in the end of the handle, in which the shanks of bits may be inserted. the screw driver is formed on the end of the screw bar, attached to the outer jaw of the wrench, and is taken out from the hollow of the handle when required for use. the use of the other parts of the tool will be apparent from the engraving. the tool is very compact, and has this advantage over the ordinary screw wrench, that its leverage increases as it is opened to receive nuts of larger size. [illustration] this invention is protected by two patents, dated respectively, may , , and july , . for further information address b. boardman & co., norwich, conn. * * * * * belt tightener. [illustration] this instrument will be found of great service in bringing together the ends of belts, the weight of which is so great that they cannot be held together by the hand while lacing. a strap engages with holes made in the belt, at the back of the holes punched for lacing, the tightening strap being provided with claws or hooks, as shown. a winch axle and ratchet, adjusted in a frame as shown, are then employed to pull the ends of the belt together and hold them firmly till the lacing is completed. this is the invention of t. g. stansberry, of medora, ill. patented in september, . * * * * * some things i don't want in the building trades. i don't want my house put in repair, or rather out of repair, by a master who employs "jacks of all trades." i don't want my foreman to tell me too much at one time about the faults of the workmen under him, as i may forget asking him about himself. i don't want a builder or carpenter to give a coat of paint to any joinery work he may be doing for me, until i have examined first the material and workmanship. i don't want any jobbing carpenter or joiner, whom i may employ, to bring a lump of putty in his tool basket. i prefer leave the use of putty to the painters. i don't want jobbing plumbers to spend three days upon the roof, soldering up a crack in the gutter, and, when done, leaving fresher cracks behind them. the practice is something akin to "cut and come again." i don't want a contractor to undertake a job at a price that he knows will not pay, and then throw the fault of his bankruptcy on "that blackguard building." i don't want any more hodmen to be carrying up the weight of themselves in their hod, as well as their bricks; i would much prefer seeing the poor human machines tempering the mortar or wheeling the barrow, while the donkey engine, the hydraulic lift, or the old gray horse, worked the pulley. i don't want house doors to be made badly, hung badly, or composed of green and unseasoned timber. i don't want houses built first and designed afterwards, or, rather, wedged into shape, and braced into form. i don't want to be compelled to pay any workman a fair day's wages for a half day's work. i don't want an employer to act towards his workmen as if he thought their sinews and thews were of iron, instead of flesh and blood. i don't want any kind of old rubbish of brick and stone to be bundled into walls and partitions, and then plastered over "hurry-skurry." trade infamy, like murder, will out, sooner or later. i don't want men to wear flesh and bone, and waste sweat and blood, in forms of labor to which machinery can be applied, and by which valuable human life and labor can be better and more profitably utilized. * * * * * correspondence. _the editors are not responsible for the opinions expressed by their correspondents._ * * * * * action of the reciprocating parts of steam engines. messrs. editors:--i have hesitated about the propriety of replying to the criticisms of your correspondent, j. e. hendricks, upon my paper, on the action of the reciprocating parts of steam engines. it is not to be expected that a truth so opposed to commonly received notions--the reception of which requires so much to be unlearned--should at once receive the assent of every one. some odd fancies on the subject are likely to be ventilated first. but your correspondent touches the root of the matter, and perhaps the fact questioned by him should be more clearly placed beyond dispute. i will dismiss the introductory part of his letter, merely observing that his "logical inference" is quite gratuitous and unwarranted. he says himself that its absurdity is obvious, in which i quite agree with him. the real question is this: what is the figure representing the acceleration of the motion of a piston, controlled by a crank which revolves with a uniform velocity? i stated it to be a right-angled triangle, and indicated, as i supposed, clearly enough, a simple method by which this could be shown. your correspondent claims that the calculation, according to my own rule, gives a figure of a totally different form, and one that shows the acceleration, as well as the motion, to be reduced to zero at the commencement of the stroke. let us see. let the straight line, aj, in the following figure, represent half the stroke of the piston, and let the distances, ab, ac, etc., on this line, represent the versed sines of °, °, etc., up to °, or the motion of the piston while the crank is moving through these arcs. at the points a, b, c, etc., erect the perpendiculars, aa, bb, cc, etc., and let the length of each of these ordinates represent the acceleration imparted in a given time at that point of the stroke. then will aj be to aa as ij is to ii, as hj is to hh, etc., showing that the straight line, aj, connects the extremities of all the ordinates, and that the triangle, aja, represents the acceleration of the motion of the piston, from the commencement to the middle of the stroke. [illustration] the following table will enable any one to make the calculations proving the truth of the above proposition: degrees. versed sine. motion for ° acceleration during °. ° . _aa_ . ° _ab_ . _ab_ . _bb_ . ° _ac_ . _bc_ . _cc_ . ° _ad_ . _cd_ . _dd_ . ° _ae_ . _de_ . _ee_ . ° _af_ . _ef_ . _ff_ . ° _ag_ . _fg_ . _gg_ . ° _ah_ . _gh_ . _hh_ . ° _ai_ . _hi_ . _ii_ . ° _aj_ . _ij_ . _jj_ . the method of obtaining the decimals representing the acceleration for °, at any point, was fully explained in the paper, and compared with the similar method of showing the uniform acceleration of a body acted on by a constant force. the ordinary tables in the hand-books, going only to five places of decimals, are of no use for these computations. i would suggest a practical experiment. let any one having an engine running at a good speed, loosen the crank pin brasses a little, so that, at starting, it will thump heavily. let the engine be lightly loaded, so that only a small portion of the boiler pressure will need to be admitted to the cylinder. as its speed increases, the thump will die away; and, if at its full speed, the pressure of the steam admitted is not so great as to overcome the centrifugal strain of the reciprocating parts on the crank, as it passes the centers, the engine will revolve in silence. any one can ascertain, by the rule given in the note to the paper, just what pressure can be admitted without causing a thump, or this can be found by a little experimenting. i am running an engine which does not thump with loose crank pin brasses, under eighty pounds pressure, admitted sharply on the centers. charles t. porter. * * * * * answer to practical problem. messrs. editors;--i submit the following solution of "practical problem" on page : given ab, arm, c, arm, d, chord of half angle of oscillation of arm, d, and angles of arms, with line ab. to find angles, bac', abb, and length of link, e. . as the length of arm, d, is to the chord of arc, ab, divided by , so is the radius to the sine angle oscillation of arm, d, divided by . . ° is to the whole circumference as the angle bba is to the length of arc ab. . now arc ab is equal to arc a'c'. . the whole circumference is to ° as the length of arc a'e' is to the angle oscillation of c divided by . . half angle oscillation, c, taken from angle baa' is equal to angle bac'. . half angle oscillation, d, taken from angle aba is equal to angle abb. . the diagonal of the rectangle formed by the (sum of the sines of the angles of the arms with ab) into (ab--sum of cosines of same) will be the length of link, e. [illustration] g. r. nash, civil engineer. north adams, mass. [we have received other solutions of this problem, but as this covers the ground in a very simple manner, we think it will be sufficient. those forwarding the solutions not published will accept our thanks and assurances that it is not because they lack merit that they are declined.--eds. * * * * * reciprocating parts of steam engines. messrs. editors:--in one of the late numbers of your journal, you publish a paper, read by mr. porter before some learned society in new york, on something about the possibility or practicability of running a steam engine at a high rate of speed, and claiming to give a scientific explanation of the why and wherefore. now, scientifically, i know nothing about a steam engine; practically, i know how to stop and start one. therefore, you will understand that what i say is not as coming from one who claims to be wise above what is written, but as simply being a statement of the case, as it appears to one who wants to learn, and takes this way to draw out the truth. a scientific theory, invested with all its sines, coefficients, and other paraphernalia, is a very pretty thing to look at, no doubt, for those who understand it, and, when properly applied, is invaluable; but when, as in this case, a practical question is to be decided, by the aid of a scientific demonstration, it will not do to throw aside the main elements of the problem, or any, in fact, of the minor points, no matter how trivial they may appear. mr. porter's labors were strictly of a scientific nature. he starts out with the proposition that what he is about to explain is very simple, and very likely it is; but, for one, i can't see it, and i want more light. he says that it takes a certain number of pounds to overcome the inertia of the reciprocating parts of a certain weight, to give it a certain speed. what is inertia? he says, "we will not take into account the friction of parts." now, my understanding of this point is, that friction is practically one of the main elements in the problem. how can we hope to obtain a correct solution when he rubs out one of the terms of the equation? what is friction doing all the time, while he is theoretically having his reciprocating parts storing up power and then giving it out again, just at the right time, and in the right quantity? what an immense amount of iron has been wasted by being cast into fly wheels, when a fraction of the amount, if only put into cross heads, would render fly wheels unnecessary! mr. porter stops short in his discussion. he should have added a table giving the proportionate length of stroke, weight of parts, and number of revolutions required to produce the effect of an engine running at a high speed, without the least fraction of inequality in the strain on the crank, and then the sun would have fairly risen in the "dawn of a new era for the steam engine." but, as it is so very simple, we can all figure it out for ourselves. in the diagram mr. porter gives, to illustrate the travel of the piston, he wets his finger and draws it over another term in the equation (a method of elimination not taught by hutton, davies, and other mathematicians). it is a quick way, but is it correct? he says, "the distance traveled by the piston is the versed sine of an angle formed by a line from the center of the crank pin, in any part of its stroke to the center of the circle described by the crank pin, leaving out of the calculation the angular vibration of the connecting rod." what he means by the "angular vibration," i do not know. he is wrong in the statement. if he will think of it he will see it. if he meant to say that the piston's travel was measured by the versed sine of the angle formed by the connecting rod and the line of horizontal centers, he is wrong again, yet nearer the truth than before, just as the proportion between the length of the connecting rod and the half diameter of the circle described by the crank pin. this can quickly be seen by supposing the connecting rod to be detached, and allowed to fall down on the center line, at any part of the stroke. if he understood this (as no doubt he did), he should not ignore the facts. what i am aiming at is this. when a man attempts to demonstrate a thing mathematically, he must take into his calculation everything essentially connected with the problem, just exactly as it is, and not as he would have it; otherwise, he cannot, by any possibility, attain a correct result. when he claims, as now, the practicability of running engines at a high speed, i think he is claiming too much. build an engine of proper materials, make it strong, and fit everything as it should be, balance crank and fly wheel to a nicety, keep everything snugly in its place, and the terrors of a quick stroke vanish. s. w. h. * * * * * test for white lead. messrs. editors:--i have read, with much interest, dr. chandler's colorimetric test of the purity of white lead, as published in the scientific american sometime ago. i enclose another test, which, though not new, is of value to all using white lead on account of its simplicity and effectiveness. it has been in use here for nearly two years, and has been found reliable. having never seen it in print, i have tried to put it in as simple words as possible. felix mcardle, analytical chemist. st. louis, mo. take a piece of firm, close grained charcoal, and, near one end of it, scoop out a cavity about half an inch in diameter and a quarter of an inch in depth. place in the cavity a sample, of the lead to be tested, about the size of a small pea, and apply to it continuously the blue or hottest part of the flame of the blow pipe; if the sample be strictly pure, it will in a very short time, say in two minutes, be reduced to metallic lead, leaving no residue; but if it be adulterated to the extent of ten per cent. only, with oxide of zinc, sulphate of baryta, whiting or any other carbonate of lime, (which substances are now the only adulterations used), or if it be composed entirely of these materials, as is sometimes the case with cheap lead, it cannot be reduced, but will remain on the charcoal an infusible mass. dry white lead, (carbonate of lead) is composed of metallic lead, oxygen and carbonic acid, and, when ground with linseed oil, forms the white lead of commerce. when it is subjected to the above treatment, the oil is first burned off, and then at a certain degree of heat, the oxygen and carbonic acid are set free, leaving only the metallic lead from which it was manufactured. if, however, there be present in the sample any of the above mentioned adulterations, they cannot of course be reduced to metallic lead, and cannot be reduced, by any heat of the blow pipe flame, to their own metallic bases; and being intimately incorporated and ground with the carbonate of lead, they prevent it from being reduced. it is well, after blowing upon the sample, say for half a minute, by which time the oil will be burned off, to loosen the sample from the charcoal, with a knife blade or spatula, in order that the flame may pass under as well as over and against it. with proper care the lead will run into one button, instead of scattering over the charcoal, and this is the reason why the cavity above mentioned is necessary. a common star candle or a lard oil lamp furnishes the best flame for use of the blow pipe; a coal oil lamp should not be used. by the above test, after a little practice, so small an adulteration as one or two per cent. can be detected; it is, however, only a test of the purity or impurity of a lead, and if found adulterated, the degree or percentage of adulteration cannot be well ascertained by it. jewellers usually have all the necessary apparatus for making the test, and any one of them can readily make it by observing the above directions, and from them can be obtained a blow pipe at small cost. if you have no open package of the lead to be tested, a sample can most easily be obtained by boring into the side or top of a keg with a gimlet, and with it taking out the required quantity; care should be used to free it entirely from the borings or particles of wood, and it should not be larger than the size mentioned; a larger quantity can be reduced, but of course more time will be required, and the experiment cannot be so neatly performed. * * * * * how to build a chimney. messrs. editors:--i am satisfied that a great many fires originate through poorly constructed chimneys; and, although not a bricklayer by trade, i would offer a few hints how to construct a fire-proof chimney. let the bed be laid of brick and mortar, iron, or stone; then the workman should take a brick in his left hand, and with the trowel, draw the mortar upon the end of the brick, from the under side, and not from the outside edge, as is usual. then, by pressing the brick against the next one, the whole space between the two bricks will be filled with mortar; and so he should point up the inside as perfectly as the outside, as he proceeds. by drawing the mortar on the edge of the brick, the space between the ends will not always be entirely filled, and will make (where the inside pointing is not attended to) a leaky and unsafe chimney, which, if not kept clear of soot, will, in burning out, stand a good chance of setting the building on fire. the best thing that i know of, to put the fire out in a burning chimney is salt; but the matter of first importance, after having a chimney properly constructed, is to keep it clean. austin b. culver. westfield, n. y. * * * * * crystallized honey. messrs. editors:--please allow me to say to the querist who, through your columns, asks what to do with crystalline honey, that if he will "doctor" it with almost any artificial honey of the day, it will not become like lard in cold weather, which change is a natural proof that it is pure. for almost any purpose, pure honey is preferable to that which has been adulterated, but purity is a minor consideration with many. next we shall hear of some fastidious customer who objects to pure lard, because it looks white when cold. to such we would recommend lard oil as a great improvement, especially for cooking purposes. a. m. b. louisville, ky. * * * * * [for the scientific american.] rambles for relics. number ii. at a depth of fifteen feet, we were about to suspend our labors, supposing from the nature and uniformly dark color of the earth, that we had reached the surface of the alluvium, when a sign of the inevitable wood and bark layer was seen in a crevice. an excavation, five or six feet, into the wall, revealed the skeleton of a man laid at length, having an extra coverlid of wooden material. eighteen large oblong beads, an ax of polished green stone, eleven arrow points, and five implements of bone (to be described) were deposited on the left side; and a few small beads, an ornamental shell pin, two small hatchets, and a sharp-pointed flint knife or lance, eight inches long, having a neck or projection at the base, suitable for a handle, or for insertion in a shaft, on the right side. the earth behind the skull being removed, three enormous conch shells presented their open mouths. one of my assistants started back as if the ghost of the departed had come to claim the treasure preserved, in accordance with superstitious notions, for its journey to the "happy lands." the alarm seemed to be a warning, for at the moment the embankment, overloaded on one side, caved in, nearly burying three workmen, myself, and a spectator. our tools being at the bottom of the heap, and the wall on the other side, shaken by the falling earth, giving tokens of a change of base, our prospects of a ready deliverance were not very hopeful. the bystanders, however, went to work with their hands, and we were soon relieved, not without casualty, the spectator having the worst of it. struggling to extricate himself, instead of abiding his time, he dragged one leg out of the pile shorter than the other. the occurrence of marine shells in a burial depository, especially of the varieties pyrula and oliva, four or five hundred miles from the gulf and that portion of the southern coast where the mollusks exist, bears upon the question of migration and tribal intercourse, and the commercial value of these articles. obtained from a distance and regarded as precious commodities, they were used in exchange, for the material of ornaments, and for choice utensils. only two or three of these shells have been found in a perfect condition, but defective ones are frequent, with fragments, "cuttings," and various trinkets made out of them--such as ornamental pins, needles, crosses, buttons, amulets, engraved plates, and beads. from one of the specimens recovered from the mound sepulchre, the spire and columella had been removed, leaving a hollow utensil. it would have been suitable for a water vessel, but for a hole in the bottom, which had furnished a button-shaped ornament, or piece of money, which was found with the relic, and exactly corresponded to the orifice. the twirled end of the shell, however, had been improved for a handle by shallow cavities, one on the inside slanting from the middle longitudinal line, and one crossing that line at right angles on the convex side, so as to be fitted to the thumb and fore finger of the left hand, suggesting a use of the implement as a shield, or a mask held before the face. adair speaks of large shells in use by the indians of his time ( ), suspended about the neck for shields, and regarded as badges of priestly dignity. a trench was dug on the east side of the mound, nearly corresponding in dimensions to the one on the west side, making the length of the whole excavation, including the central cavity, thirty-two feet. in the last opening, eight skeletons were exhumed; the mode of burial was the same throughout. the only article of value recovered was a curiously wrought pipe of stone, having a "figure head" representing the human face, which i have put down in a list of "articles stolen," and which the thief can describe better than the writer. after filling up all the gaps, and levelling the surface to suit the taste of the proprietor, we closed our labors on the mound in the bent. of the skulls collected, it is sufficient to say that they belong to the "short heads," the length and breadth having a comparative medium proportion, a common form of cranium in the mounds of tennessee. of stone implements i specify an ax of serpentine, ten inches long, two thick, and four broad, having plain sides and a straight edge ground down on both of the flat faces; hatchets ("tomahawks") of green stone, flint, and diorite, from five to eight inches long, with rounded faces and sides, contracted to an edge at one end, and to a flat heel at the other; a wedge of black slate, seven inches long and half an inch thick, of a square finish on the faces and sides and at the heel, which was diminished two inches, as compared with the length of the edge; hatchets with a serrated edge at each end, plane on both sides, convex on one face and flat on the other. with one skeleton was deposited a "set of tools," eight in number, of the species of rock before mentioned, varying in length from two to eight inches. their peculiarity consists in a variety of shapes--no two being precisely alike--and in their fitness to various uses, such as carving, hacking, paring, and grooving. the smallest of them, having a square finish, was held by the thumb and two fingers, and is suitable for cutting lines and figures in wood and shells. specimens of this art were furnished from the mound. the largest number might serve for hatchets, chisels, and gouges. one had been ground in the form of a cylinder five inches long and an inch thick, and then cut an inch on two sides to an edge, and worked into a handle with a round bead, from the center of the elliptical faces. it might be used for chipping wood and stone. one answered the purpose of a cold chisel; another was somewhat similar, but had a hollow face reduced to a curved edge for grooving. these polished instruments, wrought with much care, seemed intended for use by the hand rather than for insertion in a handle or socket, or attachment to a shaft by means of a strap or withe. only one was perforated. the drilling through granite, quartz, and diorite, without the use of metal, was a severe labor, even for savage patience. a long knife of silex, with a wrought handle, lance heads, leaf shaped, of the same material, of beautiful workmanship, arrow points of fine finish, furnished, with others before mentioned, an assortment of arms. several flint points, though only an inch long, were curved like a cimeter, and used probably as flaying instruments. true disks, of various mineral substances, from an inch to five inches in diameter, having convex faces, complete the list of stone implements. those of bone comprise several like hollow chisels, sharpened at one end, and pierced through one face, near the other extremity, so as to be fastened to a handle; these were used for dressing skins. one was formed like a poniard, with a worked hilt. with these may be connected arrow heads and sharp pointed weapons of the worked antlers of the stag, and tusks of the wild boar. of ornaments, i noticed pins used for dressing the hair, made of the columns of large sea shells. the head is generally round, sometimes oval, from an eighth to a half of an inch in diameter, retaining the diagonal groove of the pillar from which it is made. the stems vary in length from one to six inches. it would be tedious even to classify ornamental beads and buttons of shell work, such as are usually found in the mounds. these trinkets are perforated, and, in addition to their being articles of dress, were used probably as "wampum," the currency of the recent indians. a miscellaneous collection includes a hematite stone, wrought in the shape of a cup weighing half a pound; when rubbed or ground it furnished the war paint of the savages; also the extremity of a copper tube, two inches long; needles in bone and shell, from an inch to six inches long, with grooves round the head, to serve the purpose of eyes; and plates of mica. the use of mica plates, which are found of large size in some of the western mounds, has excited some inquiry. of a certain thickness, they make good mirrors. beside their use for ornamental purposes, they were probably looking-glasses of the beauties of the stone age. there was also found a pipe of soap stone, having a stem five inches long, and a bowl with a broad brim, like a quaker's hat. of earthenware, there was an endless variety of fragments of the usual black, grey, or red compressed clay, mixed with pulverized shells or stones. one kind i have never seen described. the sherds had a red coating on both sides, an eighth of an inch in thickness, evidently not a paint or a glaze. the red coloring might have come from the pottery being burnt in the open air, instead of baked in a furnace, were not the layer of uniform thickness and of homogeneous paste, unlike the material of the vessel, which was a gray mixture of clay and particles of shells. i give the above memoranda to the general fund of information, touching a subject that invites inquiry on account of its novelty and ethnological importance. every examination of the monumental remains of the ancient americans brings to light some new feature in structure or type of rudimental art. and since archæology has become a science, investigators, for half a century, may be looking about for facts to complete the system auspiciously introduced by the antiquarians of northern europe, and advanced in our own country by the researches of caleb atwater (_archæologia americana_) and by those of the smithsonian contributors to knowledge, especially squier and davis. rambler. * * * * * a small water wheel.--there is in the town of meriden, conn., a leffel double turbine wheel, running under feet fall and driving a manufactory. it uses only about one-half of a square inch of water, and runs at the marvelous speed of , revolutions per minute, or revolutions per second, which is by far the most rapid rate of motion ever imparted to a water wheel. this is, also, beyond comparison the greatest fall applied to the propulsion of a wheel in america. the wheel at meriden is of the most diminutive size, scarcely exceeding in dimensions the old-fashioned "turnip" watches which our grandfathers used to carry in their capacious vest pockets. the complete success of this wheel has attracted much attention and affords further evidence of the wide range of adaptability of the leffel turbine. * * * * * [for the scientific american.] silk culture. by w. v. andrews. a vague notion that silk culture ought to form one of the industrial pursuits of the american people seems to be prevalent enough; but it does not take practical hold upon anybody. the nearest approach to anything practical which we have seen, in late years--excepting, of course, what has been done in california--occurred in new york in july last, when a number of gentlemen pledged themselves, according to a report given in the _tribune_ of july , "to promote the native silk trade." the gentlemen present at the meeting represented the most prominent silk manufacturing and importing houses in this country. what these gentlemen have since done towards promoting the native silk trade, i do not know, but, having pledged themselves, it is presumed they have done something. at the meeting, of which the _tribune_ article is a report, dags, and other things, manufactured from california silk, were exhibited; and the report goes on to say that "mr. warren also exhibited samples of native and foreign cocoons, and of raw and thrown silk, together with the common _cecropia_ and _bombyx cynthia_, species of silkworms which feed upon oak leaves. * * also the _bombyx yamamai_ which feeds upon mulberry leaves; also the _bombyx pernyi_, of which the cocoons are early as good as the cocoons of worms fed upon mulberry leaves." i have given this extract, word for word, as it stands in the columns of the _tribune_, because it contains more blunders of one kind or another than i remember ever to have seen in so many words. _cecropia_ is certainly not very particular as to its food, but it is not an oak feeder. _cynthia_ will thrive on nothing except ailanthus, though it will eat one or two other things, but not oak. the _yamamai_, on the other hand, will eat oak, indeed it is its natural food; but mr. warren errs greatly when he says that it will feed on mulberry. the last clause of the sentence, which says that cocoons of _pernyi_ are nearly as good as those of worms fed on mulberry leaves, must be a sort of entomological joke, of which the point is not discoverable by me, so i pass it over. i do not, however, notice this report on account of its grammatical and entomological mistakes. it is because of the evil effects it may, and probably will, have on amateur silk culturists, that i notice it; for most assuredly, failure will be the result of all attempts to produce silk cocoons by feeding the caterpillars of the different moths on the food prescribed by mr. warren. any patriotic, money making farmer, who believes in the _tribune_, purchasing _yamamai_ eggs and setting his worms to feed upon mulberry, which they refuse to eat, and consequently, all die, will probably give up silk culture as being nothing more or less than a humbug. and thus the cause is injured. for several years past, i have made some experiments in the rearing of the silkworms, giving the result of my experience in the first year in vol. ii., page , of the _american naturalist_; and of a subsequent year in the _entomologist_, for november, . the paper in the _naturalist_ is devoted to my experiments with the ailanthus silkworm, _samia cynthia_ (g. & r.), a naturalized species from the east. in that paper, i have said all that is necessary to say at present, on that species, except perhaps that i am further convinced, from the inspection of samples of sewing and other silks, made from the cocoons of _cynthia_, that one day it will be reared very extensively in the united states. it is perfectly hardy, is double brooded, and may be reared by any one possessed of a few acres of land, which may be good enough for growing ailanthus trees, but not good enough to grow any thing else. the labor of a few old men, or women, or even children, is sufficient for the purpose. the cost is therefore trifling. the objection to the cultivation of _cynthia_ is that the cocoon cannot be reeled. but it can be carded, and if the chinese can make excellent silk goods from it, why cannot we? i suspect, too, that _cynthia_ silk can be worked in with cotton, or, perhaps, woolen goods, adding to their beauty and durability (for it is indestructible in wear), and thus open up branches of manufacture hitherto unknown. for manufacturers of coarse goods, i have no doubt that the silk from our native silk moths, _cecropia_ and _polyphemus_, may be used. indeed, i believe that m. trouvelot is of opinion that _polyphemus_ may fairly enter into competition with _bombyx mori_, the ordinary mulberry silkworm. the worm, however, is rather difficult to rear. in reference, however, to _bombyx mori_, it is well known that the silk crop in france and italy has been reduced greatly, and the price of silk goods consequently enhanced, by prevalence of disease among the worms. so much is this the case, that silk breeders have been obliged to look around for some silk-producing moths whose products may, at any rate, supplement the deficient crop. _cynthia_, as already mentioned as one of these, and two others mentioned by warren in the _tribune_ reports above adverted to, are at present the subjects of experiment. my article mentioned before as appearing in the _american entomologist_ is mainly devoted to my experiments, and those of my correspondents, with _yamamai_, which, as i said before, is an oak feeder. in japan, which is its native country, it feeds, in its wild state, on _quercus serrata_. whether that oak be found in america, i do not know, but it is of little importance, as the worm will feed on almost any species of oak, although i think that it prefers white oak. the importance of acclimatizing new species of silk moths is of so much prospective importance, that i shall devote the remainder of this article to the consideration of whether _yamamai_ and _pernyi_ may not be naturalized here. any one, who happens to have the number of the _entomologist_ containing the article above alluded to, may find it worth while to read it, but as many persons may not be able to obtain that number, i will here repeat the substance of my remarks, adding as much new matter as subsequent experience has afforded. the silk from the _yamamai_ being considered superior to that produced by any other of the substitute silk moths, great efforts have been made in europe to acclimatize it; but, it must be confessed, hitherto with but slight success. there are exceptions, however, particularly among amateurs in germany, sufficient to show that success is possible. the baron de bretton raises about , cocoons annually. in this country but little has been done, or attempted, and that little has not been very successful. the fact is, that _yamamai_ is a difficult moth to rear in a country like this, where in early spring the temperature varies so much; but that success is possible, i am convinced. the moth emerges from the cocoon in the latter part of the summer, copulates, lays its eggs, and of course dies. and now the trouble commences; that is, with eggs laid, say in japan, from whence we mainly get our supplies. as soon as the egg is laid, the young larva commences its formation, which in a short time (about one month) is perfected. it lies in the egg in a quiescent state till early spring. if the egg remain in the country where it is laid, and is kept at a pretty even temperature, and free from damp, the caterpillar emerges in a healthy condition. but if it be removed some thousands of miles, passing in the transit from heat to cold, and back to heat again: and if, in addition, it be closely confined in a damp place, with little or no circulation of air, the egg is attacked by a fungus which sometimes prevents the worm from emerging at all; or, if it emerge, it is in a sickly condition. that these conditions obtain in the transit of eggs, from japan to europe, and thence to america, is evident enough; and it may, therefore, require the efforts of many persons, continued for a long time, to enable us to acclimatize the _yamamai_. but this is all that is required, and i feel confident that ultimate success is certain. on hatching out, the worm is of a brimstone yellow, and thinly covered with strong hairs; after the second month it is greenish, with black, longitudinal streaks, and the thread a dull coral red color. after the third month it becomes of a fine apple green, with yellow tubercles on each segment, from which issue a few black hairs. the head and legs are chocolate brown, the prolegs reddish, and the first segment edged with pinkish color. the greatest care is necessary, as the spring advances, to prevent the eggs from hatching before the oak buds are ready for them, and the temperature must be regulated with the greatest nicety. if the eggs can be kept somewhere about deg. fah., it would be quite safe; higher than that the mercury should not be allowed to rise, till you are quite ready for the worms, and, on the other hand, the eggs should not be allowed to freeze. on emerging from the eggs, the worms should be allowed either to crawl to the oak branches, or rather to sprigs obtained for that purpose, the end of which should be placed in a jar, or bottle, of water, or the worms may be placed on gently with a camel-hair brush. the leaves should be well sprinkled with clean water that the caterpillars may drink. from some cause, not well understood, the young caterpillars have a tendency to wander; and if care be not taken many may be lost. to prevent this, it is well to cover the branches with a gauze bag, tied tightly around the stems, and close to the bottle. care must also be taken that the caterpillars do not find their way into the water, which they assuredly will if they have the opportunity, committing suicide in the most reckless manner. if the number of caterpillars be few, it is a good plan to place them at the outset with their food, in a wide-mouthed bottle, covering the mouth with gauze. the branches, particularly if the weather be warm, must still be occasionally sprinkled, so that the caterpillars may have the opportunity of drinking. it must be remembered that experiment is necessary in rearing _yamamai_, but one thing is ascertained, and that is, that the worms must not be exposed to direct sunshine, at least not after seven or eight in the morning. if the spring be warm, i am inclined to think that a northeastern exposure is the best, and we may sum up by saying, that comparatively cool and moist seasons are more favorable to success that hot, dry weather. in america the worms suffer in the early spring, from the rapid changes of temperature, ° at a.m. increasing to ° in the afternoon and falling off to freezing point during the night. the worms cannot stand this. they become torpid, refuse to eat, and consequently die. to prevent this, if the nights be cold, they must be placed where no such change of temperature can occur. it is scarcely necessary to say that an ample supply of fresh food must be always supplied, but it may not be amiss to say that it is well, when supplying fresh branches, to remove the worms from the old to the new. the best way of doing this is to clip off the branch, or leaf, on which the worm is resting, and tie, pin, or in some way affix the same to the new branches. if this be not done, they will continue to eat the old leaf, even if it be withered, and this induces disease. if the worm has fastened itself for the purpose of moulting, the best way is to remove the entire branch, clipping off all the dried leaves before so removing it. these remarks apply, in general, to the treatment of all silkworms, except _bombyx mori_. the results of numerous experiments with _yamamai_ go to show that it is, as i said before, a difficult worm to rear; but it has been reared near new york to the extent of eight hundred cocoons out of sixteen hundred eggs, and this, although not a remunerative result, is encouraging. the chinese silk moth, _aulterea pernyi_, also an oak feeder, has been successfully raised by me and by others, for several years. eggs have been sold to persons in states widely separated, and the results show that this worm is perfectly hardy. the moth winters in the cocoon, emerges early in may, if the weather be warm, pairs readily, and lays from to eggs. these hatch out in about fourteen days, and like _yamamai_, always about or o'clock in the morning. it is necessary to be on the alert to catch them on hatching only, and to remember that they are vagabonds, even to a greater extent than _yamamai_. consequently similar precautions must be taken. the worm on emerging from the egg is large, and of a chocolate-brown color. after the first month it becomes of a yellowish green; head, pale brown; feet and prolegs of nearly the same color. the body has numerous reddish tubercles, from which issue a few reddish hairs. at the base of some of the tubercles on the anterior segments are silvery patches. the _pernyi_ worm is much more easily reared than that of _yamamai_, but still great care is needed; fresh food of course is essential, and a slight sprinkling of the branches and worms in very warm weather is advisable; although it is not so necessary as with _yamamai_. it is remarkable that _pernyi_ worms, fed in the open air, on oak trees, do not, at present, thrive so well as those fed in-doors, but this, doubtless, is a question of acclimation. i advise white oak (_quercus alba_) as food, if it can be readily obtained, but failing that, pin oak (_quercus palustris_) will do; and i have no doubt that they will feed on any kind of oak. they will, indeed, feed on birch, and on sweet gum (_liquidambar_), but oak is the proper food. it is worthy of remark that _pernyi_ bears a strong resemblance to our _polyphemus_, but it is more easily reared in confinement, and double brooded; an important fact for the silk culturist. from american reared eggs, i obtained cocoons as early as july th, the perfect insect emerging on july . copulation immediately ensued, and the resulting eggs hatched only on august , ten days only from the time of laying; and as the worm feeds up in about four or five weeks, this affords plenty of time for rearing the second brood. it must be remembered that on the quantity and quality of food, much depends, not only with _pernyi_ but with all caterpillars. by furnishing food sparingly the time of feeding would be much prolonged. i have already said that both _yamamai_ and _pernyi_ should be fed under shelter for the reasons given, but there is another reason of less importance. the young worms are liable to be attacked by spiders and wasps, and even after the second month, they are not safe from these enemies. i have seen a wasp bite a large caterpillar in two, carry off the anterior section and return for the posterior, which had held on by its prolegs. did the wasp anticipate this fact, and therefore carry off the anterior part first? as to the spiders, they form a series of pulleys and hoist the caterpillar off its legs, sucking its juices at leisure. and now i must devote a few words to the advisability of silk culture from a pecuniary point of view. _bombyx mori_, or the ordinary mulberry silkworm, is, of course, the best to rear, if you can obtain healthy eggs. but this is the difficulty, and thence arises the necessity of cultivating other silk-producing species. i imagine that silk can be produced in most of the states of the union, and manufactured from the cocoon at a large profit; but for the present, we will leave the manufacture out of the question, and consider only, whether it will not pay to rear eggs and cocoons for sale? it must be remembered that european manufacturers are at this moment largely dependent on foreign countries for the supply of both eggs and cocoons; and this, because of the general prevalence of disease among all the races of _bombyx mori_. and now, to what extent does the reader suppose this dependence exists? of cocoons i have no returns at hand, but, of raw silk, european manufacturers purchase, annually, not less than $ , , worth; and of eggs (_bombyx mori_) to the value of $ , , . this, then, is a business of no trifling amount. california seems to be alive to the fact, and, i am informed, raised, this last season, $ , , cocoons; and, for sale, about , ounces of eggs, worth at least $ per ounce, wholesale. now, there is no earthly reason why california should monopolize this business. why are not companies formed in other states for this purpose? or if private individuals lack the enterprise or the means, why do not the legislatures, of those states most favorably located, do something by way of starting the business? a few thousand dollars loaned, or even donated, may prove to be a valuable investment for the people at large, and, even supposing a failure, would not be a very great loss to any body. so far as farmers are concerned, it may interest them to know that one man in england, capt. mason, clears $ per acre by rearing silkworms (_bombyx mori_ in this case), and i much doubt whether any crop raised here pays as well. by way of commencement, then, let everybody that has sufficient leisure set to work, and rear as many silkworms, of the above-named species, as he possibly can; and if the process be not remunerative in a pecuniary sense, it most assuredly will be in the amount of pleasure and knowledge obtained. one caution i must give to those who cultivate _bombyx mori_. although _yamamai_ requires sprinkled branches, _bombyx mori_ does not; nor must the leaves be furnished to them while wet with rain or dew. * * * * * effect of cold upon iron.--the article upon this subject, giving experiments of fairbairn and others, referred to in our editorial upon the same subject, in our last issue, was crowded out by press of matter. the reader will find it in the present number. * * * * * universal boring machine. our readers will recollect an illustrated description of an universal wood-working machine, published on page , vol. xiii. of the scientific american. the machine herewith illustrated is manufactured by the same firm, and is a valuable addition to the many excellent wood-working machines now in use. a boring machine, though one of the simplest, is by no means an unimportant adjunct to a full outfit of wood-working machines. the one shown in our engraving is one of the most complete ever brought to our notice, and the great variety of work it is capable of performing, renders the name chosen for it peculiarly applicable. it is called the "universal boring machine" because the most prominent feature of its construction is its power to bore a hole in any desired angle with the axis of the bit. any sized bit required is inserted into the chuck, which is adjustable to fit large and small shanks. the mandrel which carries the chuck is made to traverse by a foot lever, so as to bore any depth up to twelve inches. the mandrel is driven by belt from a cone pulley of three faces, which gives the proper speeds for different sized bits. slots and stops upon the table enable the work to be set at any desired angle on the horizontal plane, while the table can be set on an incline to any angle not exceeding forty-five degrees. the table is twenty-one inches wide, with fifteen inches slide, and it can be raised or lowered fifteen inches. the countershaft rests in self-adjusting boxes, and has a tight and a loose pulley eight inches in diameter. the traversing mandrel is of the best quality of steel, and the machine is otherwise made of iron in a substantial manner. [illustration: mcbeth, bentel, & margedant's universal boring machine.] the several adjustments enable the operator to do all kinds of light and heavy boring, with ease and with great rapidity. this machine was awarded the first premium at the cincinnati industrial exposition, in october, , and was patented through the scientific american patent agency, aug. , . it is manufactured by mcbeth, bentel and margedant, of hamilton, ohio, whom address for machines rights to manufacture, or other information. * * * * * combined trunk and rocking chair. a unique invention, calculated to increase the comforts of travellers on steamboats, ships, and in crowded rooms of hotels, is illustrated in the engraving published herewith. it is the invention of t. nye, of westbrook, me., and was patented by him, june , . it is a combined trunk and rocking chair. the rockers are made to fold into recesses, where they are retained by suitable appliances till wanted. the trunk being opened, as shown, forms a back to the seat, which is held by metallic braces. when closed, the whole presents the appearance of an ordinary trunk. [illustration] * * * * * cosmetics. the extensive use of preparations for hiding nature's bloom on the human countenance, and presenting to our view a sort of metallic plaster, suggests the inquiry, "how are these pigments made?" without going into an unnecessary analysis of the "bloom of youth," the "rejuvenator," the "corpse decorator," or the other inventions for destroying the skin, with which the druggists' stores abound, we may state again the fact, always unheeded, that all the detestable compounds are injurious. they are nearly all metallic poisons, and, if there be any that are innocent of this charge, they are in every instance harmful to the health. the color and surface of the skin cannot be changed by any application which does not close the pores; the pores, which are so exquisitely fine that there are millions of them to the square inch, and which must be kept open if a healthy and cleanly body is to be preserved. there is more breathing done through the pores of a healthy person than through the lungs; and we need not remind our readers of a ghastly piece of cruelty once enacted in paris (that of gilding the body of a child, for a triumphal procession, which killed the subject in two hours), to show that the stoppage, in any degree, of the natural functions of so important an organ as the skin, is injurious. the immediate effect of the use of such compounds is to destroy the vitality of the skin, and to render it, in appearance, a piece of shriveled parchment. we must warn our readers that a temporary and meretricious "bloom" can only be attained at the cost of future freshness and lively appearance, so that a year or two of "looking like paint" is followed by a long period of "looking like dilapidation." * * * * * smith's infant dining chair. the accompanying engraving illustrates a convenient and cheap infant dining chair, which can be attached to any of the ordinary chairs in common use. [illustration] it consists of a chair without legs, suspended by the posts of the back, as shown, on pins engaging with hooked bars, which are placed upon the back of an ordinary chair. the details of the device will be seen by a glance at the engraving. the chair is adjusted in hight by placing the pins in the proper holes in the posts made for this purpose. for further information, address smith, hollenbeck & co., toledo, ohio. * * * * * the medicines of the ancients. at the recent commencement of the homeopathic college in this city, mr. s. h. wales, of the scientific american addressed the graduating class, and from his remarks, we quote the following: "many writers of our time persist in regarding this, above all others, as the best period in the history of our race; and, doubtless, it is true in many important respects. but i cannot forbear the suggestion at this moment that there was a time in the history of the world when the science of medicine was unknown, when people lived to the incredible age of many centuries; and, even after the span of life had been reduced to threescore and ten, sickness was comparatively unknown. in ancient times, it was looked upon as a calamity, that had overtaken a tribe or people, when one of its members prematurely sickened and died. "other arts and sciences flourished in rome long before medicine was thought of; and the historian tells us that the first doctor who settled in rome, some two hundred years before christ, was banished on account of his poor success and the very severe treatment applied to his patients; and it was a hundred years before the next one came. he rose to great popularity, simply because he allowed his patients to drink all the wine they wanted, and to eat their favorite dishes. some writer on hygiene has made the statement that the whole code of medical ethics presented by moses consisted simply in bathing, purification, and diet. this simplicity of life was not confined to the wandering tribes who settled in the land of canaan, but was the universal custom of all nations of which history gives us any account. this simple arrangement for health was considered enough in those primitive times, when the human system had not been worn out and exhausted by depletive medicines. the luxuries of public baths, athletic sports and games were deemed ample, both to educate the physical perceptions and to prevent disease. "all this wisdom, which had its origin in ancient games and sports of the field, led to the erection of extensive bath-houses, and the adoption of other healthful luxuries to which all the people could resort to recreate their wasted powers." * * * * * barnes' ventilator for mattresses, etc. many diseases are caused by the use of beds not properly aired; and it is difficult, if not impossible, to properly air, or ventilate, a mattress, made in the usual manner. if this could be done more thoroughly than it generally is, much sickness would be avoided. [illustration] to secure this object cheaply and efficiently is the design of the invention herewith illustrated. by it a complete circulation of air through the mattress is secured, which carries off all dampness arising from constant use. thus the mattress becomes more healthy for sleeping purposes, more durable and better fitted for the sick room. the ventilators consist of coiled wire, covered with coarse cloth (to prevent the stuffing closing up the tube), running through the mattress in all directions. the ends of the coils are secured to the ticking by means of metal thimbles, inside of which are pieces of wire gauze, to prevent insects getting in, but which admit air freely. the cost of the ventilators is small, and they will last as long as any mattress. they can be applied to any bed at small expense. this invention was patented through the scientific american patent agency, january , . the right to manufacture will be disposed of in any part of the country. further information can be obtained by addressing the proprietors, barnes & allen, hoosick falls, n. y. * * * * * the third annual exhibition of the national photographic association takes place at horticultural hall, philadelphia, june , . prof. morton is to deliver two lectures on light. * * * * * a scientific and technical awakening. our english cotemporary, _engineering_, appears to have seriously exercised itself in the perusal of our good-natured article on "english and american scientific and mechanical engineering journalism," which appeared in the scientific american, february th; at least, we so judge from the tenor of an article in response thereto, covering a full page of that journal. the article in question is a curiosity in literature. it deserves a much wider circulation than _engineering_ can give it, and we would gladly transfer it to our columns, but for its exceeding length--a serious fault generally, not only with _engineering's_ articles, but most other technical journals published in england. it would scarcely do for them to be brief in their discussions, and above all other things, spice and piquancy must always be excluded. _engineering_ evidently labors under the conviction that the heavier it can make its discussions, the more profoundly will it be able to impress its readers. hence, we are equally astonished and gratified to find a gleam of humor flashing out from the ordinary sober-sided composition of our learned contemporary. the article came to us just as we were laboring under an attack of dyspepsia, and its reading fairly shook our atrabilious _corpus_. we said to ourselves, "can it be possible that _engineering_ is about to experience the new birth, to undergo regeneration, and a baptism of fire?" the article is really worth reading, and we begin to indulge the hope that at least one english technical is going to try to make itself not only useful, but readable and interesting. and what is most perplexingly novel in this new manifestation, is the display of a considerable amount of egotism, which we had always supposed to be a sinful and naughty thing in technical journalism. and, as if to magnify this self-complaisance, it actually alludes to its "_own extensive and ever-increasing circulation in america_." now to show how small a thing can impart comfort to the soul of our cotemporary, we venture to say that the circulation of _engineering_ in this country cannot much exceed three hundred copies per week. it evidently amazes our english cotemporary that a journal like the scientific american, which, according to its own notions, is chiefly the work of "scissors and paste," should circulate so widely; and it even belittles our weekly circulation by several thousand copies, in order to give point to its very amusing, and, we will also add, generally just criticism. the writer in _engineering_, whoever he may be, appears to be a sort of literary rip van winkle, just waking out of a long sleep; and he cannot get the idea through his head that it is possible that a technical journal can become a vehicle of popular information to the mass of mankind, instead of being the organ of a small clique of professional engineers or wealthy manufacturers, such as seems to hold control of the columns of _engineering_, and who use it either to ventilate their own pet schemes and theories, or to advertise, by illustration and otherwise, in the reading columns, a repetition of lathes, axle-boxes brakes, cars, and other trade specialities, which can lay little or no claim to novelty. it is, furthermore, a crying sin in the estimation of our english critic that american technical journals do not separate their advertisements from the subject matter; and he thinks that when yankee editors learn that trade announcements are out of place in the body of a journal, they will see how to make their journals pay by making them higher priced. now we venture to say, without intending to give offence, that yankee editors understand their business quite as well as do english editors; and it is presumable, at least, that they know what suits their readers on this side, much better than do english editors. we venture to suggest--modestly, of course--that journalism in the two countries is not the same, and should the editor of _engineering_ undertake to transfer his system of intellectual labor to this side of the atlantic, he would not be long in making the discovery that those wandering bohemian engineers, who, he tells us, are in sorrow and heaviness over the short-comings of american technical journals, would turn out after all to be slender props for him to lean upon. we think it probable, however, that with a little more snap, a journal like _engineering_ might possibly attain a circulation, in this country, of or copies weekly. why, american engineers have scarcely yet been able to organize themselves into an association for mutual advancement in their profession, much less to give the reading public the benefit of their experience and labors! this fact alone ought, of itself, to satisfy _engineering_ that no such journal could profitably exist in this country. whenever our american engineers are ready to support such a journal, there will be no difficulty in finding a publisher. _engineering_, in its casual reference to the various technical journals of america, omits to name our leading scientific monthly, but introduces with just commendation a venerable cotemporary, now upwards of three score years of age. now, it is no disparagement of this really modest monthly to say, that perhaps there are not sixty hundred people in the states who know it, even by name; and so far as the use of "scissors and paste" are made available in our technical journals, we venture the assertion that the editorial staff expenses of the scientific american are as great, if not greater, than those of _engineering_. the question, however, is not so much one of original outlay, but which of the two journals gives most for the money. in this very essential particular, and with no intention to depreciate the value of _engineering_, we assert, with becoming modesty, that the scientific american occupies a position which _engineering_ will never be able to attain. * * * * * the sherman process. when people boast of extraordinary successes in processes the details of which are kept profoundly hidden from public scrutiny, and when the evidences of success are presented in the doubtful form of specimens which the public has no means of tracing directly to the process, the public is apt to be skeptical, and to express skepticism often in not very complimentary terms. for a considerable time, the public has been treated to highly-colored accounts of a wonderful metallurgic process whereby the best iron and steel were said to be made, from the very worst materials, almost in the twinkling of an eye. this process has been called after its assumed inventor, or discoverer, the "sherman process." the details of the process are still withheld, but we last week gave an extract from an english contemporary, which throws a little light upon the subject. the agent relied upon to effect the remarkable transformation claimed, is iodine, used preferably in the form of iodide of potassium, and very little of it is said to produce a most marvellous change in the character of the metal. a very feeble attempt at explaining the rationale of this effect has been made, in one or two english journals, which we opine will not prove very satisfactory to chemists and scientific metallurgists. the _engineer_ has published two three-column articles upon the subject, the first containing very little information, and the second a great number of unnecessary paragraphs, but which gives the proportion of the iodide used, in the extremely scientific and accurate formula expressed in the terms "a small quantity." assertions of remarkable success have also been given. nothing, however, was said of remarkable failures, of which there have doubtless been some. a series of continued successes would, we should think, by this time, have sufficed for the parturition of this metallurgic process, and the discovery would ere this have been introduced to the world, had there not been some drawbacks. we are not prepared to deny _in toto_ that the process is all that is claimed for it; but the way in which it has been managed is certainly one not likely to encourage faith in it. the very name of "process" implies a system perfected, and if it be still so far back in the experimental stage that nothing definite in the way of results can be relied upon, it is not yet a process. if, in the use of iodine, in some instances, fine grades of iron or steel are produced, and in as many other experiments, with the same material, failures result, it is just as fair to attribute the failures to the iodine, as the successes. a process worthy the name is one that acts with approximate uniformity, and when, in its use, results vary widely from what is usual, the variation may be traced to important differences in the conditions of its application. on the whole, we are inclined to believe mr. sherman's experiments have not yet developed a definite process, and we shall receive with much allowance the glowing statements published in regard to it, until such time as it can face the world and defy unbelief. the patents obtained by mr. sherman seem to cover the use of iodine, rather than the manner of using it, and throw no light upon the rationale of the process. a patent was granted by the united states patent office, sept. , , to j. c. atwood, in which the inventor claims the use of iodide of potassium in connection with the carbons and fluxes used in making and refining iron. in his specification he states that he uses about _fifteen grains_ of this salt to eighty pounds of the metal. this is about / of one per cent. he uses in connection with this exceedingly small proportion of iodide of potassium, about two ounces of lampblack, or charcoal, and four ounces of manganese, and asserts that steel made with these materials will be superior in quality to that made by the old method. these claims we are inclined to discredit. certainly, we see no chemical reason why this small amount of iodide should produce such an effect, and the specification itself throws no light upon our darkness. if the experiments in these so-called processes have no better basis than is apparent from such information as at present can be gathered respecting them, it is probable we shall wait some time before the promised revolution in iron and steel manufacture is accomplished through their use. * * * * * rubber tires for traction engines. when it was first discovered that a smooth-faced driving wheel, running on a smooth-faced rail, would "bite," the era of iron railways and locomotive engines may be said to have fairly commenced. the correction of a single radical error was, in this case, the dawn of a new system of travel, so extensive in its growth and marvelous in its results, that even the wildest dreamer could not, at that time, have imagined the consequences of so simple a discovery. a popular and somewhat similar error regarding the bite of wheels on rough and uneven surfaces, has also prevailed. we say popular error, because engineers have not shared it, and it has obtained, to any notable extent, only among those unfamiliar with mechanical science. the error in question is, that hard-surfaced wheels will not bite on a moderately rough surface, sufficiently to give an efficient tractile power. it seems strange that this error should have diffused itself very extensively, when it is remembered that a certain degree of roughness is essential to frictional resistance. the smoothness of the ordinary railway track is roughness compared to that of an oiled or unctuous metallic surface; and it has been amply demonstrated that the resistance of friction, of two bearing surfaces depends, not upon their extent, but upon the pressure with which they are forced together. a traction wheel, of given weight, resting upon two square inches of hard earth or rock, would develop the same tractile power as though it had a bearing surface of two square feet of similar material. on very rough and stony ways, however, another element practically of no importance on moderately rough ways, like a macadam surface or a concrete road, where the prominences are nearly of uniform hight, and so near together as to admit between their summits only very small arcs of the circumference of the wheel; comes into action. this element is the constantly recurring lifting of the superincumbent weight of the machine. even this would not result in loss of power, could the power developed in falling be wholly applied to useful work in the direction of the advance of the engine. the fact is, however, that it is not so applied, and in any method of propulsion at present known to engineering science, cannot be so applied. above a certain point where friction enough is developed to prevent slip, the more uneven the road surface is, the greater the power demanded for the propulsion of the locomotive. and this will hold good for both hard and soft-tired wheels. what then is the advantage, if any, of rubber-tired wheels? the advantages claimed may be enumerated as follows: increased tractile power, with a given weight, secured without damage to roadways; ease of carriage to the supported machinery, whereby it--the machinery--is saved from stress and wear; and economy of the power, expended in moving the extra weight required by rigid-tired wheels, to secure the required frictional resistance. the last-mentioned claim depends upon the first, and must stand or fall with it. the saving of roadway, ease of carriage, and its favorable result upon the machinery, are generally conceded. a denial of the first claim has been made, by those interested in the manufacture of rigid-tired traction engines and others, in so far as the rubber tires are employed on comparatively smooth surfaces; although the increased tractile power on quite _rough_ pavements and roads is acknowledged. this denial is based upon results of experiments performed on the streets of rochester, england, between the th october and the nd november, , by a committee of the royal engineers (british army), with a view to determine accurately the point in question. care was taken to make the circumstances, under which the trials took place, exactly alike for both the rubber and the iron tires. the experiments were performed with an aveling and porter six-horse power road engine, built in the royal engineers' establishment. the weight of the engine, without rubber tires, was , pounds; with rubber tires, it weighed , pounds. without rubber tires it drew . times its own weight up a gradient of in ; with rubber tires, it drew up the same incline . times the weight of engine, with the weight of rubber tires added; showing that, although it drew a little over , pounds more than it could do without the rubber tires, the increase of traction was only that which might be expected from the additional weight. it is claimed, moreover, that the additional traction power and superior ease of carriage on rough roads, secured with rubber tires, is dearly bought at the very great increase in cost, of an engine fitted with them, over one not so fitted. this is a point we regard as not fully settled, though it will not long remain in doubt. there are enough of both types of wheels now in use to soon answer practically any question there may be of durability (upon which the point of economy hinges), so far as the interest on the increased cost due to rubber tires, is offset against the greater wear and tear of iron rimmed wheels. it is stated, on good authority that a rubber tired engine, started at work in aberdeen, scotland, wore out its tires between april and september, inclusive, and when it is taken into consideration, that the cost of these tires is about half that of other engines, made with solid iron rimmed driving wheels, it will be seen that, unless very much greater durability than this can be shown for the rubber, the advantages of such tires are very nearly, if not more than, balanced by their disadvantages. the fact that one set of tires wore out so soon does not prove a rule. there may have been causes at work which do not affect such tires generally, and it would be, we think, quite premature to form favorable or unfavorable judgment, of relative economy from such data as have been yet furnished. the difference in the current expenses of running the two most prominent types of engines, with hard and soft tires, now in use, does not affect the question of rubber tires, unless it can be shown that these tires necessitate, _per se_, such a form of engine as requires a greater consumption of fuel, and greater cost of attendance, to perform a given amount of work. * * * * * central shaft of the hoosac tunnel. as many of our readers have evinced much interest and ingenuity on the question of the propriety of placing reliance upon the accuracy of dropping a perpendicular from the top to the bottom of a shaft , feet in depth, by means of an ordinary plummet, we take the earliest opportunity of settling the matter beyond dispute, by reporting the results lately obtained, through a series of experiments by the engineers in charge, for the ultimate purpose of laying down the correct line for the tunnel. the perpendicular line has, of course, been dropped many times, and the main result taken. the plummet used is made of steel, properly balanced and polished, in shape something like a pineapple, and of about the same size, weighing fifteen pounds. it was suspended, with the large end downwards, by a thin copper wire, one fortieth of an inch in diameter, immersed in water; and, after careful steadying with the hand, occupied about an hour in assuming its final position or motion, which, contrary to the expectation and theories of many, resulted in a circular motion around a fixed point, the diameter of the circle being a mean of one quarter of an inch. the suspending wire in these operations was not quite the entire length of the shaft, being only feet; and before the plummet had settled, the wire had stretched nearly twenty feet. the suspension of the plummet in water was not considered necessary for any other reason than that water was continually trickling down the wire, and dropping on the plummet. the experiments so far have not been of the perfect character it is determined to attain, when the final alignment is made, as, until the headings east and west of the shaft have advanced to a considerable distance, any slight error would be of no account. a neat and ingenious instrument has been constructed for determining the variation of the plummet, and will be used when great accuracy is desired; the plummet will also be suspended in oil. the bearing of the tunnel is about s. ° e.; but, independently of its near approach to the line of revolution described by the earth, it is not considered necessary to take into account any motion it may derive from this cause. in fact, the opinion is, that the motion of the earth will not practically have any effect. on the whole, after the still imperfect experiments which have been made, enough is established to show there is no difficulty to be encountered, other than the accurate and delicate manipulation of the plummet and its attachments. the shaft headings are progressing favorably. the rock is not so hard or varied as that met with at the west end markings. already nearly feet have been taken out, and with the proved energy of the contractors, this great task will doubtless be prosecuted steadily and surely to completion, within the contract time expiring march , . * * * * * a museum of art and natural history. our recent articles on "scientific destitution in new york" and "the scientific value of the central park," have called forth numerous letters from correspondents, and have been extensively noticed by the press. we now learn that the legislature of the state has taken the matter in hand, and there is some prospect, with an honest administration of the appropriations, of something being done to relieve our city of the opprobrium that rests upon it. a bill is pending, before the senate, authorizing the park commissioners to build, equip, and furnish, on manhattan square, or any other public square or park, suitable fire-proof buildings, at a cost not exceeding $ , for each corporation, for the purpose of establishing a museum of art, by the metropolitan museum of art, and of a museum of natural history, by the american museum of natural history, two societies recently incorporated by the legislature. this is a million dollars to begin with, and an ample site, without cost, to the aforementioned corporations. manhattan square extends from seventy-seventh to eighty-first streets, and from eighth to ninth avenues, and spans about eighteen acres. until it was set apart by the state board of commissioners, for the purposes of a zoological garden, it was proposed, by a number of enlightened citizens of new york, to devote it to the uses of four of our existing corporations, giving to each one a corner, and an equal share in the allotment of space. the societies were, "the academy of design," for art, "the historical society," for public records and libraries, "the lyceum of natural history," for science, and "the american institute," for technology. these have been incorporated for many years, and are known to include the leading artists, men of letters, science, and the arts, of the city, on their lists of members. the committee went so far as to have plans of the building drawn by competent architects; but, like many other well-meant schemes, want of money compelled the originators of the plan to abandon any further attempts. in the meantime, the legislature chartered the american botanical and zoological society, and gave the commissioners of the park authority to set apart a portion of it, not exceeding sixty acres, for the use of the society, for the establishment of a zoological and botanical garden. this society was duly organized under the act, and mr. hamilton fish was made its president, and considerable sums of money were subscribed. but, according to the sixth annual report of the board of commissioners, "the society never manifested its desire for an allotment of ground." it appears to have died, and made no sign. some of our citizens, fearing that the central park would go the way of every other public work in the city, made strenuous effort to revive the zoological society, for the purpose of obtaining a perpetual lease of a suitable site, on which to establish a zoological garden, similar to those in london, paris, amsterdam, and cologne. their object was to remove this part of the park beyond the reach of political intrigue. subsequent events have shown that the fears of these gentlemen were well founded. the legislature of the state, on the th of march, , gave ample powers to the new york historical society to establish a museum of antiquity and science, and a gallery of art, in the central park. they have submitted designs for a building, but, for some reason, no decisive steps have been taken towards its construction. the lyceum of natural history was also negotiating with the commissioners, for the use of the upper rooms of the arsenal for its collections, and there is no doubt that an arrangement to this effect would have been made, if a fire had not destroyed the entire collections of the lyceum. the lyceum made great effort to raise money to purchase a new collection, but without avail; and, although this is the oldest scientific society in new york, and has inrolled in its list of members, nearly every professional scientist of the city, it is probably the poorest, in income and resources, of any academy of sciences in the world. we do not know that the academy of design has ever applied for a home in the central park; and we cannot speak for the american institute, nor for the geographical society, in this particular. as we stated in our former article, the old board of commissioners appears to have become weary of the unsuccessful attempts on the part of numerous societies to divide up and apportion the central park, and they applied to the legislature for authority to conduct matters in their own way. an act was duly passed, authorizing the board "to erect, establish, conduct, and maintain, on the central park, a meteorological and astronomical observatory, a museum of natural history, and a gallery of art, and the buildings therefor, and to provide the necessary instruments, furniture, and equipments for the same." here would seem to be ample power for the establishment of museums of science and art, but nothing is said about the manner of raising the money. one would suppose, however, that, by means of the "central park improvement fund," abundant means could have been raised. the bill now before the legislature puts matters in a new light. if it does not conflict with previous enactments, nor destroy vested rights, it has the appearance of being a thoroughly practical way of solving the question of art and science for the city. the metropolitan museum of art and the american museum of natural history are in the hands of the most respectable citizens of new york. it would not be possible to find a body of men of more unimpeachable integrity and greater worth, than the gentlemen who have founded these two societies. it is impossible that they should lend their names to anything that will not bear the closest scrutiny; hence the proposition, now before the legislature, to put up buildings for them, at a cost of a million dollars, must attract unusual attention. if the state would appropriate the money to these corporations, giving them the control of its expenditure, we should have considerably more confidence in its honest administration than, we are grieved to say, we can feel under the present circumstances; and if we knew what other institutions are to have the remaining portions of manhattan square, it would be a great relief to our minds. "we fear the greeks bringing gifts," but are willing to accept the gifts, if the officers of the two organizations are certain that it is all right. the need of a museum of natural history, and of a gallery of art, in new york, is so pressing that there is some danger of our accepting the appropriations without a proper regard to consequences. the court house is not yet finished, and the foundations of the post-office are scarcely laid. * * * * * report of the judges of group , department v. of the exhibition of the american institute for . the allen engine. the labors of the judges in this department were much lighter in the last exhibition than in the preceding one, and we are happy to say, were, in our opinion, so far as the award of premiums is concerned, much more fairly performed. the award of two first premiums to two competing engines could scarcely be repeated this time, as there was in reality no competition. the allen engine was the only important one entered, and of course received the first premium. the engine is, however, one that evidently could have competed favorably with those previously exhibited. we are in receipt of advanced sheets of the judges' report pertaining to the critical examination of this engine, being a record and account of experiments performed under the supervision of washington lee, c. e. the experiments were very comprehensive, and comprised approved tests, of each important detail, usually made by expert engineers. the report is too voluminous for reprint or even for condensation in our columns. in looking it through, we are satisfied that the experiments were accurately made, and that the engine exhibited great working efficiency and economy. as the engine has been recently illustrated and described in our columns, we deem it unnecessary to dwell upon the details of its construction. the water test of the previous exhibition was employed, the water being this time measured, with indisputable accuracy, in a tank, instead of by a meter as before. the voluminous comparison of this engine with those previously exhibited, seems unnecessary, and we think not in good taste in such a report, however much it may possess of scientific interest. moreover, the circumstances under which the trials were respectively performed, render the comparison difficult, if not unfair. mr. lee concludes his report with a thorough endorsement of the theory of mr. porter upon the action of the reciprocating parts of engines, as set forth by the last named gentleman in recent articles in this journal. he says: "under the resistance of . horse powers at the brake, the motion of the engine was remarkably uniform; not the least diminution of speed in passing the centers could be detected, illustrating very satisfactorily the value, in this respect, of the speed employed, and of the action of the reciprocating parts of the engine in equalizing the rotative pressure on the crank through the stroke. the governor was, during the trials and through the exhibition, nearly motionless, while the load remained constant, and instantaneous in its action on changes of resistance, maintaining a steadiness of running which left nothing to be desired." the judges--prof. f. a. p. barnard, thos. j. sloan, and robert weir--speak in their report as follows: "the performance of this engine has exceeded that of the two fine engines which were on trial here last year. the results seem to be without precedent in such engines. the engine ran from to hours repeatedly without showing a sign of a warm bearing, displaying thorough perfection in all its parts. in all respects the engine is first-class, and from the fact of its presenting weight with speed, as a requisite for perfection in steam engines, it has opened a new era in this necessary branch--its economy having been clearly demonstrated in the careful trials, which ought to be published in full." * * * * * lyceum of natural history. there was an unusually large attendance of members at the meeting of the lyceum of natural history, on monday evening, the th inst., to listen to an address by professor b. waterhouse hawkins, on the progress of the work of the restoration of the forms of extinct animals in the central park. mr. hawkins gave an account of the difficulties he encountered at the outset, in finding any skeletons of animals in new york, with which to make comparisons, and he was finally compelled to go to boston and philadelphia for this purpose. after much study and many delays, the casts of the _hadrosaurus_ were completed, and numerous smaller skeletons prepared. at this stage of the proceedings an entire change in the administration of the park took place, and the newly appointed commissioners decided to suspend the work upon the palæozoic museum, and they dismissed mr. hawkins from their service. the announcement that an end had thus been summarily put to one of the most important educational projects ever started in this country, was received by the lyceum with profound surprise. for a few minutes after the close of mr. hawkins' report, no one felt disposed to make any comment, but as the truth of the great damage became apparent, there was considerable disposition manifested to have the society give expression to its sense of the value of mr. hawkins' services in the cause of education, and their regret that so important a work should be suspended at this critical period. remarks were made by dr. newbery, professor joy, mr. andrew h. green, professor seely, dr. walz, mr. e. g. squier, and others, and the following resolutions were unanimously adopted: _resolved_, that the lyceum of natural history, in the city of new york, has learned with deep regret of the temporary suspension of the work of restoration of the forms of extinct animals, as hitherto prosecuted in the central park, under the able superintendence of professor waterhouse hawkins. _resolved_, that the society considers the proposed palæozoic museum not only a valuable acquisition to the scientific treasures and resources of the city, but also as a most important adjunct and complement to our great system of public education. * * * * * warming and ventilation of railroad cars. there has been enough of denunciation against the present general method of warming and ventilating railway cars. it produces no effect on the corporations who could, if they would, adopt appliances that would not burn people to death in cases of accident, nor regularly and persistently poison them with bad air. there is no lack of ways and means; the problem is simple and easily solved; nay--a not very extensive search through the patent office records will show that it has been solved already; perhaps not in the most practical and perfect manner, but still solved so well, as, were it not for corporation cupidity, would greatly add to the comfort and safety of passengers. the real problem is how to compel corporations to recognize the fact that the public has rights they are bound to respect. it is the disregard of these rights that fills our cars with smoke, dust, and exhalations, and puts box stoves full of hot coals in the corners, ready to cook the human stew whenever a frisky car shall take a notion to turn a somersault. the invention needed is a conscience for corporations--an invention, by the way, scarcely less difficult than the one advertised for in our last issue, namely, a plan for preventing the sale of intoxicating liquors and tobacco in new jersey. the _railroad gazette_, imitating the english ideal of prolixity in discussion, for which _engineering_ has recently patted it on the back approvingly, treats us, in its issue of february th, to a page article, to be continued, under the title of "warming and ventilation of railroad cars." in this article the writer takes the ground that people in general are ignorant of the effects of pure air, and not being able to "see the foulness," they "therefore do not believe it exists." it is quite possible they may not be able to see the foulness, but if in the majority of railroad cars run in this country, they are not able to feel it in gritty, grimy accumulations on skin and linen, and smell it in suffocating stenches which serve, with sneeze-provoking dust, to stifle anything like comfort, their skin must be thicker, their linen more neglected, and their noses less sensitive than those of the majority of fellow travellers it has been our fortune to be cooped up with for a day's railroad journey. the _railroad gazette_ makes this wholesale charge of ignorance and insensibility the excuse for an essay on the physiology of respiration, mostly extracted from huxley's "elementary lessons in physiology," and therefore excellent in its way, though having a somewhat remote bearing upon the subject as announced in the title of the article. we trust that before this journal concludes its series of articles thus commenced, it will tell how to breathe into the breasts of the corporations which choke us in their human packing boxes, something resembling the soul which they are universally acknowledged to be destitute of. when this is done, carbonic acid, ammoniacal smells, organic exhalations, smoke, and dust, will be invited to shun the interiors of railway cars, and comparative comfort will descend upon the peregrinating public. * * * * * the mineral resources of missouri. the incalculable wealth, which lies hid in the bosom of mother earth, in our vast possessions of the west, is undoubtedly centered in the state of missouri; and the development of this fund of riches must add to the national prosperity, not only by its immeasurable intrinsic value, but by its affording occupation to armies of laborers, the latter being the highest and most important consideration. in - , a geological survey of the state was wisely decided upon, and a liberal provision for its execution made. two valuable reports, by professor swallow, have been printed, in the year , but the notes of his subsequent investigations have not been made public. in the session of - , further action, in this important public work, was taken by the state legislature, and arrangements made for a still more accurate and detailed examination, under the direction of professor a. d. hager, of vermont. the distribution of metals all over the state will be seen in the following figures, taken from the st. louis _journal of commerce_, which show the number of counties in which the various ores are found: iron in counties, lead in , coal in , copper in , marble in , zinc in , fire clay in , barytes in , nickel in , granite in , tin in , plumbago in , gypsum in , alum in , antimony in . there is probably no country in the world so endowed as this. of iron alone, according to the state geologist's report for , there is ore of the best quality, sufficient to furnish , , tuns of iron; and this quantity lies in a small space, in the vicinity of pilot knob and iron mountain, and within miles of st. louis. the quality of the iron is highly spoken of by the manufacturers, and the capacity of the smelting appliances has reached to over , tuns per annum. the coal is well suited for reduction of ores, either by hot or cold blast treatment. the scotia iron co. commenced operations in january, ; and, although the materials for building blast furnaces had to be carried miles into a desert, the first furnace was blown into blast in august, . this furnace will run about tuns per day. the company procures ore from a hill, near the furnace, in which there is an apparently inexhaustible supply of red oxide and brown specular. this ore yields per cent of pure metal. the erection of mills for making wrought iron is contemplated, and the high quality and prodigious quantity of the raw material will justify and reward any outlay of capital in this direction. the shipment of ore to other states goes on constantly, the last year's account showing that , tuns were dispersed over indiana, ohio, and others. the furnaces at kingsland, south st. louis, lewis iron co.'s works, carondelet, and maramec are all well situated as to coal and limestone, the maramec works having a most valuable water-power. these latter works also ship about , tuns red hematite ore yearly. * * * * * scientific intelligence. according to _petermann's mittheilungen_, the new german empire, including alsatia and lorraine, will embrace , square miles, with , , inhabitants. russia alone will exceed it in extent and population, for russia in europe has , square miles with a population of , , . france, after the loss of alsatia and lorraine, will have , square miles of territory, with , , inhabitants. austria will number , , inhabitants spread over a larger extent of country, namely, , square miles. great britain and ireland has , square miles, with , , inhabitants; and italy, including rome, has , square miles, with , , inhabitants. in the order of population, the governments will stand: russia, germany, france, austria, and england; but in military power, the first position must henceforth be accorded to germany. american institute of mining engineers. a circular has been issued by several mining engineers, proposing a meeting at wilkes-barre, some time in april or may next, of all persons interested in the general subjects of mining and metallurgy, for the purpose of establishing an association, to be called "the american institute of mining engineers." the institute will hold meetings periodically "in the great mining and metallurgical centers, when works of interest, such as mines, machine shops, furnaces, and other metallurgical works, can be inspected, and the members exchange their views, and consult, for mutual advantage, upon the difficulties encountered by each." there will be the usual publication of "transactions" and "proceedings." the idea of forming an association of persons thus mutually interested in each other's occupations, is an excellent one; but it has been suggested by a number of scientific gentlemen that the american association for the advancement of science offers every facility for the accomplishment of the objects set forth in the circular, while it affords the very great advantage of an assemblage of men learned in all departments of knowledge, whose acquaintance mining engineers would do well to make, and from whom they could learn much, while at the same time imparting of their own knowledge. as a section of the american association, the mining engineers would have more influence before the country, and it would perhaps be well for them to stop and consider before establishing a separate institute. consumption of sugar, coffee, and tea. e. behm gives in his geographical year book, for , the following estimate of the consumption of sugar, coffee, and tea, _per capita_, in various countries: countries. sugar, lbs. coffee, lbs. tea, lbs. great britain . . . united states . . ..... holland . . . france . . . norway . . . sweden . . . switzerland . . ..... germany . . . denmark . . . belgium . . . portugal . . . italy . . . austria . . . spain . . . russia . . . the entire consumption of sugar in europe has averaged, during the last few years, three thousand four hundred and ten million pounds ( , , pounds), and for the whole world it is set down at nearly twice that amount. it is estimated that three fourths of the sugar is made from cane, and one fourth from the beet. the consumption of coffee has doubled in most countries during the last twenty years. * * * * * unpleasant discovery in the patent office--levying black mail. "the patent office has been, during the past week, in a high state of excitement, occasioned by the discovery of the operations of e. w. w. griffin, clerk in charge of the draftsmen's division, who, it appears, has been levying black mail on the lady employés of the office, for nearly two years. during the administration of colonel fisher, late commissioner of patents, a large number of ladies were employed, for the purpose of recopying drawings, when ordered by the inventors, of patents already on file. "these ladies were placed under charge of griffin, with power to retain them in office so long as their services were satisfactory. it has been proved that griffin hired the ladies at regular salaries of $ , per annum, the most of whom he blackmailed to the amount of $ per year each. it is estimated that he has made $ , per month for the past two years. "the matter was brought to the notice of commissioner duncan, and an investigation ordered, which resulted in the dismissal of griffin. "it is thought that there are other cases of this kind, and the commissioner expresses his determination to ferret them all out, and make a clean sweep of all parties in his department engaged in swindling operations, against the government or against individuals. "the patent office has for a long time been considered a rich field for operations of this kind, and investigations have often been suggested, but passed unheeded by the proper authorities. "it is openly stated that an investigation into the relations existing between certain examiners of patents and certain patent agents, would disclose a more fearful state of blackmailing than exists in all the other government departments combined." [we find the above sensational paragraph among the recent washington items of the _evening mail_. we are in a position to say that "the high state of excitement" alluded to has existed only in the brain of the newspaper correspondent. the facts, in brief, are these: in july, , a lady, and wife of one of the clerks in the draftsmen's room, made application to commissioner fisher for a position in the copying division of the same department; and, upon the urgent solicitation and recommendation of mr. e. w. w. griffin, chief of the division, she was appointed, and has held the position from that time until now, receiving as salary $ , per annum, which, with the full knowledge of her husband, she has divided with griffin, in consideration of his services in procuring for her the appointment. about a month ago, one of the lady's friends got hold of the matter, and reported it to the court, which resulted in an investigation and the subsequent dismissal of griffin. this is the only case of the kind that we have heard of, and we have no reason to believe that there is any other, or that corruption exists in the examining corps, as alleged.--eds. * * * * * a method of testing the purity of samples of water, by watching the rapidity of its action on soap and similar compounds, has been introduced by the french _savants_, mm. boutron and boudet. the experiment tests, at the same time, the purity of the soap. dissolved in water in which lime is held in solution, the soap is precipitated in hard white flakes. if the quantity of soap put in the lime water be noted, it will be found that the smaller the quantity producing precipitation, the purer the soap. the _journal de pharmacie et de chemie_ (of paris) reports some experiments, on this subject, by m. f. schulze. * * * * * louisiana state fair.--the fifth state fair of the mechanics, and agricultural fair association of louisiana will commence in the city of new orleans, on saturday, april , , and continue nine days. over $ , in premiums are offered. rules, regulations, and schedule of premiums may be obtained of the secretary and treasurer, luther homes, esq., new orleans, la. * * * * * knitted goods.--john kent advertises, in this paper, valuable machinery for the manufacture of knitted goods, to which we invite the attention of all who are interested in this branch of industry. mr. kent has devoted many years to the perfection of these machines. * * * * * kaolin, a white clay, used largely in the adulteration of flour, starch, and candles, is found near augusta, ga., and is sent to the northern states in large quantities. * * * * * we are indebted to james vick, practical florist, rochester, n. y., for a choice variety of flower seeds. * * * * * new books and publications. a complete guide for coach painters. translated from the french of m. arlot, coach painter, for eleven years foreman of painting to m. eherler, coach maker, paris. by a. a. fesquet, chemist and engineer. to which is added an appendix, containing information respecting the materials and the practice of coach and car painting and varnishing, in the united states and great britain. philadelphia: henry carey baird, industrial publisher, walnut street. london: sampson low, son & marston, crown buildings, fleet street. . price, by mail, to any part of the united states, $ . . this is another of the large number of practical works and industrial treatises issued from the press of mr. baird. it is intended as a practical manual for the use of coach painters, and we must say, upon examination of its contents, that we think it admirably adapted to meet the wants of that class of artisans for which it has been prepared. there is perhaps no department of decorative art in which there is greater room for the display of skill and taste than in coach painting. this work, however, does not deal with the subject of art, to any great extent. its aim is to give information in regard to colors, varnishes, etc., and their management in carriage painting in the plainest manner, and in this way it thoroughly fulfils the intention of the author. on the generation of species. by st. george mivart, f. r. s. london: macmillan & co. . the darwinian theory of the origin of species, has, perhaps, aroused more attention, excited more dispute, and won more converts in a shorter time among scientific and unscientific men, than any other of equal importance promulgated in the th century. it seems to be the rule either to swallow the theory whole, or reject it as unworthy of belief, and as conflicting with orthodoxy. the author of the work before us has, however, taken a middle ground, from which we opine it will be difficult to dislodge him, though it is within full range of the batteries of both the contending parties. while he admits the truth of darwin's views regarding the operation of natural selection as a cause of the origin of species, he denies that it is the sole cause, yet maintains that if it could be demonstrated to be the sole cause, it would in no manner conflict with orthodox belief in the scriptures as the revelation of god to mankind. the perfect candor of the author is one of the marked features of the discussion, and his style is a model of pure terse english writing, seldom, if ever, excelled by any scientific writer. the work is an octavo, most beautifully printed on tinted paper, and illustrated by many fine wood engravings. the architect's and builder's pocket companion and price book, consisting of a short but comprehensive epitome of decimals, duodecimals, geometry and mensuration; with tables of u. s. measures, sizes, weights, strengths, etc., of iron, wood, stone, and various other materials; quantities of materials in given sizes and dimensions of wood, brick, and stone; and a full and complete bill of prices for carpenter's work; also rules for computing and valuing brick and brick work, stone work, painting, plastering, etc. by frank w. vogdes architect. philadelphia: henry carey baird, publisher, walnut street. price by mail, postpaid, $ . this is a small work, but printed in small type, and containing a large amount of useful matter, thoroughly indexed for reference; bound in morocco; and provided with a clasp, so as to be conveniently carried in the pocket. gas superintendent's pocket companion for the year . by harris & brother, gas meter manufacturers, nos. and cherry street, philadelphia. philadelphia: henry carey baird, industrial publisher, walnut street. we find in this pocket-book much of interest to gas consumers, as well as to gas makers. the subject of meters is fully discussed. the work is bound in pocket-book style, in flexible morocco binding. price, by mail, postpaid, $ . * * * * * business and personal. _the charge for insertion under this head is one dollar a line. if the notices exceed four lines, one dollar and a half per line will be charged._ * * * * * the paper that meets the eye of manufacturers throughout the united states--boston bulletin, $ . a year. advertisements c. a line. half interest for sale in established machinery depot, new and second-hand. steam fitting connected. small capital, with energy, required. address t. v. carpenter, advertising agent, box , new york. see advertisement of a woolen mill for sale. a bargain. i am active, have a clear record, and some capital. how can i make some money? f. carmill, box , boston, mass. pattern letters for machinists, molders, and inventors, to letter patterns of castings, all sizes. address h. w. knight, seneca falls, n. y. improved mode of graining wood, pat. july , ' , by j. j. callow, cleveland, o. see illustrated s. a., dec. , ' . send stamp for circular. can a round, spring-steel rod be drawn to any desired length, with a true taper to a point, with equal elasticity the whole length, and rolled temper? what is the price per hundred pounds, and where can they be procured? answer "sportsman," malone, n. y. manufacturers of foot lathes and other light machinery please address geo. b. kirkham, e. d st., n. y. city. business of importance! safety kerosene lamps (perkins & house's patent). explosion or breaking impossible; light equal to gas, and no odor. families supplied and canvassers appointed, by montgomery & co., barclay st., new york, or cleveland, o. all parties wanting a water wheel will learn something of interest by addressing p. h. wait, sandy hill, n. y., for a free circular of his hudson river champion turbine. ashcroft's low water detector, $ ; thousands in use; year's experience. can be applied for $ . send for circular. e. h. ashcroft, boston, mass. wanted.--machines for manufacturing pails, tubs, and matches. also, competent man to superintend construction of buildings, and manage all parts of business when complete. address, with descriptive circulars, price, etc., no. lexington avenue, new york. turbine water wheels, portable and stationary engines, gang and circular saw mills, rolling mill machinery, and machinery for axe manufacturers, manufactured by wm. p. duncan, bellefonte, pa. for best power picket header in use, apply to wm. p. duncan, bellefonte, pa. new blind wirer and rod cutter. b. c. davis & co., binghamton, n. y. self-testing steam gage. there's a difference between a chronometer watch and a "bull's eye." same difference between a self-tester and common steam gage. send for circular. e. h. ashcroft, boston, mass. see advertisement of l. & j. w. feuchtwanger, chemists, n. y. $ . . stephens' patent combination rule, level, square, plumb, bevel, etc. see advertisement in another column. agents wanted. american boiler powder co., box , pittsburgh, pa., make the only safe, sure, and cheap remedy for "scaly boilers." orders solicited. belting that is belting.--always send for the best philadelphia oak-tanned, to c. w. arny, manufacturer, cherry st., phil'a. e. howard & co., boston, make the best stem-winding watch in the country. ask for it at all the dealers. office maiden lane, n. y. for mining, wrecking, pumping, drainage, and irrigating machinery, see advertisement of andrews' patents in another column. the best place to get working models and parts is at t. b. jeffery's, south water st., chicago. brown's coalyard quarry & contractors' apparatus for hoisting and conveying material by iron cable. w. d. andrews & bro, water st., n. y. improved foot lathes. many a reader of this paper has one of them. selling in all parts of the country, canada, europe, etc. catalogue free. n. h. baldwin, laconia, n. h. peteler portable r. r. co. contractors, graders. see adv'ment. e. p. peacock, manufacturer of cutting dies, press work. patent articles in metals, etc. franklin st., chicago. peck's patent drop press. milo peck & co., new haven, ct. millstone dressing diamond machine--simple, effective, durable. for description of the above see scientific american, nov. th, . also, glazier's diamonds. john dickinson, nassau st., n. y. steel name stamps, figures, etc. e. h. payn, m'f'r, burlington, vt. cold rolled-shafting, piston rods, pump rods, collins pat. double compression couplings, manufactured by jones & laughlins, pittsburgh, pa. keuffel & esser fulton st., n. y., the best place to get st-class drawing materials, swiss instruments, and rubber triangles and curves. for solid wrought-iron beams, etc., see advertisement. address union iron mills, pittsburgh, pa., for lithograph, etc. for the best self-regulating windmill in the world, to pump water for residences, farms, city buildings, drainage, and irrigation, address con. windmill co., college place, new york. the merriman bolt cutter--the best made. send for circulars. h. b. brown & co., fair haven, conn. taft's portable hot air, vapor and shower bathing apparatus. address portable bath co., sag harbor, n. y. (send for circular.) glynn's anti-incrustator for steam boilers--the only reliable preventive. no foaming, and does not attack metals of boilers. price cents per lb. c. d. fredricks, broadway, new york. for fruit-can tools, presses, dies for all metals, apply to bliss & williams, successor to may & bliss, , , and plymouth st., brooklyn, n. y. send for catalogue. d-hand worthington, woodward and novelty pumps, engines to h. p., horse loc. boiler. w. d. andrews & bro., water st., n. y. agents wanted, to sell the star bevel. it supersedes the old style. send for circular. hallett & white, west meriden, conn. english and american cotton machinery and yarns, beam warps and machine tools. thos. pray, jr., weybosset st., providence, r. i. for small, soft, gray iron castings, japanned, tinned, or bronzed, address enterprise manufacturing company, philadelphia. conklin's detachable rubber lip, for bowls, etc., works like a charm. for rights, address o. p. conklin, worcester, mass., or a. daul, philadelphia, pa. to ascertain where there will be a demand for new machinery or manufacturers' supplies read boston commercial bulletin's manufacturing news of the united states. terms $ . a year. * * * * * facts for the ladies. in , mrs. w. made, with her wheeler & wilson machine, , vests, besides doing her family sewing for six persons. * * * * * the pittsburgh, pa., "leader" says: "the firm of geo. p. rowell & co. is the largest and best advertising agency in the united states, and we can cheerfully recommend it to the attention of those who desire to advertise their business scientifically and systematically in such a way; that is, to secure the largest amount of publicity for the least expenditure of money." * * * * * after an exhaustive trial, at american institute fair for , pratt's astral oil was pronounced the safest and best. * * * * * dyspepsia: its varieties, causes, symptoms, and cure. by e. p. miller, m. d. paper, cts.; muslin, $ . address miller, haynes & co., west twenty-sixth st., new york city. * * * * * vital force: how wasted and how preserved; or, abuses of the sexual function, their causes effects and means of cure. by e. p. miller m. d. paper, cts. address miller, haynes & co., west twenty-sixth st., new york city. * * * * * answers to correspondents. * * * * * _correspondents who expect to receive answers to their letters must, in all cases, sign their names. we have a right to know those who seek information from us; besides, as sometimes happens, we may prefer to address correspondents by mail._ _special note.--this column is designed for the general interest and instruction of our readers, not for gratuitous replies to questions of a purely business or personal nature. we will publish such inquiries, however, when paid for as advertisements at . a line, under the head of "business and personal."_ _all reference to back numbers must be by volume and page._ * * * * * mixing metals.--all the hard gray american charcoal iron, of which car wheels and all such work are made, requires more heat and a longer time to melt than soft iron, especially scotch pig, which is the most fluid and the easiest to melt of any iron. consequently, unless the melter exercises good judgment in charging, the scotch pig will melt and run off before the car-wheel iron is melted. if g. h. p. be particular in the quality and strength of his iron, he will make better results by using soft american charcoal pig, with old car-wheel iron. it will make stronger castings, mix better, and melt more uniformly; but he should always recollect in charging his furnace that soft iron will melt before hard in the same position, in the cupola. i also think he had better use a larger proportion of soft pig, as every time cast iron is melted it becomes harder, so much so that iron which can be filed and turned with ease, when re-cast will often be found too hard to work.--j. t., of n. y. hardening tallow.--if e. h. h. will use one pound of alum for every five pounds of tallow, his candles will be as hard and white as wax. the alum must be dissolved in water, then put in the tallow, and stirred until they are both melted together, and run in molds.--f. o. h. l. l., of n. y.--according to ure, strass is made as follows: ounces of pure rock crystal or flint, in powder, mixed with ounces of salt of tartar, are to be baked and left to cool. the mixture is then poured into hot water, and treated with dilute nitric acid till it ceases to effervesce, and the "frit" is then washed in water till the water comes off tasteless. the frit is then dried, and mixed with ounces of white lead, and this last mixture reduced to fine powder, and washed with distilled water; ounce of calcined borax is now added to every ounces of the mixture, the whole rubbed together in a porcelain mortar, melted in a clean crucible, and poured out into pure cold water. this melting and pouring into water must be done three times, using a clean, new crucible each time. the third frit is pulverized, five drachms of niter added, and then melted for the last time, when a clean, beautiful white crystal mass results. c. m. s., of wis.--there are no precise proportions observed in making the coal-tar and gravel walks of which you speak. the aim is to saturate the gravel with the hot tar without surplus. the interstices of the gravel are simply to be filled, and the amount required to do this depends wholly upon the coarseness or fineness of the gravel employed. w. p. t., of ohio.--two teams of horses, of equal strength, pulling against each other, by means of a rope, would create the same tension in the rope, as one of the teams drawing against an immovable object. w. h. b., of va.--ice can be made by compressing air, and, after it has radiated its heat, allowing it to extract the heat of water with which it is brought into contact. the temperature of air at ° fah., would be raised, by compressing the air to one fourth its original volume, to ° fah; and the air would radiate and absorb again, in expanding, about units of heat. e. t. h., of ga.--the friable sandstone, a specimen of which you send us, may, we think, be rendered firmer by soaking it in a solution of silicate of soda, and allowing it to stand till dry. j. a. v., of ohio.--the use of steam expansively, by means of cut-off appliances, enables the expansive force of the steam to be utilized, which cannot be done when the pressure is maintained at one standard, and steam admitted through the fall stroke. it takes no more power to do a given amount of work in one case than in the other, but more boiler capacity, and more fuel, as the working power of the steam is more economically applied when the cut-off is used. geo. f. r., of ohio.--type metal is composed of parts lead and part antimony for smallest, hardest, and most brittle types; of lead and of antimony for next grade; of lead and of antimony for medium sizes; of lead and of antimony for larger types; and of lead and of antimony for the largest. e. j. m., of texas.--the term "power of a boiler" means its evaporating power, and in that sense is proper. if its evaporative power be sufficient to perform a given amount of work, it is proper to estimate that work in horse power. water can not be pumped out of a pipe from which atmospheric air is excluded. a pipe driven into a soil impervious to air, can never yield water unless the water is forced up by hydraulic power, as in the artesian system. a. p. y., of n. y.--you will find descriptions of iron enamelling processes, on pages and , vol. xii. of this journal. it can be done in colors. see ure's "dictionary of arts and manufactures." h. c., of pa.--we do not think increasing the size of the journals of your car axles from ½ inches to inches diameter, would make them run lighter. h. h. a., of n. y.--the lining up of a beam engine, in a vessel, is a process for which no definite mode of procedure is exclusively applicable. it is an operation to which common sense and judgment must be brought, and for which each engineer must be a law unto himself. j. s., of va.--the use of horizontal propellers to force balloons up or down is not a new suggestion. it has been tried, but, we believe, without much practical success. j. t .s., of n. y.--you will find further information on the subject of transmitting power by compressed air, in our editorial columns of last week. * * * * * applications for extension of patents. harvesters.--william t. b. read, chicago, ill., has petitioned for an extension of the above patent. day of hearing, may , . mode of fastening sheet metal on roofs, etc.--asa johnson, brooklyn, n. y., has petitioned for an extension of the above patent. day of hearing, may , . method of printing in colors.--rosalie croome, brooklyn, n. y., has petitioned for an extension of the above patent. day of hearing, may , . machinery for compressing gaseous bodies.--william a. royce, newburgh, n. y., has petitioned for an extension of the above patent. day of hearing, may , . plows.--john s. hall, pittsburgh, pa., has petitioned for an extension of the above patent. day of hearing, may , . carriage wheels.--james d. sarven, new haven, conn., has petitioned for an extension of the above patent. day of hearing may , . * * * * * new patent law of . instructions how to obtain letters-patent for new inventions. * * * * * information about caveats, extensions, interferences, designs, trade-marks, and foreign patents. * * * * * for twenty-five years, munn & co. have occupied the leading position of solicitors of american and european patents. during this long experience they have examined not less than _fifty thousand inventions_, and have prosecuted upwards of thirty thousand applications for patents. in addition to this they have made, at the patent office, _twenty-five thousand_ special examinations into the novelty of various inventions. the important advantage of munn & co.'s american and european patent agency is that the practice has been tenfold greater than that of any other agency in existence, with the additional advantages of having the aid of the highest professional skill in every department and a branch office at washington, that watches and supervises cases when necessary, as they pass through official examination. munn & co., ask special attention to their system of doing business. _consultation and opinions free._ inventors who desire to consult with munn & co. are invited to call at their office park row, or to send a sketch and description of the invention, which will be examined and an opinion given or sent by mail without charge. a special examination is made into the novelty of an invention by personal examination at the patent office of all patented inventions bearing on the particular class. this search is made by examiners of long experience, for which a fee of $ is charged. a report is given in writing. to avoid all possible misapprehension, munn & co. advise generally, that inventors send models. but the commissioner may at his discretion dispense with a model--this can be arranged beforehand. munn & co. take special care in preparation of drawings and specifications. if a case should for any cause be rejected it is investigated immediately, and the rejection if an improper one set aside. no extra charge is made to clients for this extra service. munn & co. have skillful experts in attendance to supervise cases and to press them forward when necessary. rejected cases. munn & co. give very special attention to the examination and prosecution of rejected cases filed by inventors and other attorneys. in such cases a fee of $ is required for special examination and report; and in case of probable success by further prosecution and the papers are found tolerably well prepared, munn & co. will take up the case and endeavor to get it through for a reasonable fee to be agreed upon in advance of prosecution. caveats are desirable if an inventor is not fully prepared to apply for a patent. a caveat affords protection for one year against the issue of a patent to another for the same invention. caveat papers should be carefully prepared. the government fee on filing a caveat is $ , and munn & co.'s charge for preparing the necessary papers is usually from $ to $ . reissues. a patent when discovered to be defective may be reissued by the surrender of the original patent, and the filing of amended papers. this proceeding should be taken with great care. designs, trade-marks, & compositions can be patented for a term of years, also new medicines or medical compounds, and useful mixtures of all kinds. when the invention consists of a medicine or compound, or a new article of manufacture, or a new composition, samples of the article must be furnished, neatly put up. there should also be forwarded a full statement of its ingredients, proportions, mode of preparation, uses, and merits. canadians and all other foreigners can now obtain patents upon the same terms as citizens. european patents. munn & co. have solicited a larger number of european patents than any other agency. they have agents located at london, paris, brussels, berlin, and other chief cities. a pamphlet containing a synopsis of the foreign patent laws sent free. munn & co. could refer, if necessary, to thousands of patentees who have had the benefit of their advice and assistance, to many of the principal business men in this and other cities, and to members of congress and prominent citizens throughout the country. all communications are treated as confidential. _address_ munn & co., no. park row, _new york._ * * * * * recent american and foreign patents. _under this heading we shall publish weekly notes of some of the more prominent home and foreign patents._ * * * * * self-acting shackle and car brake.--lyman alphonzo russell, shrewsbury, vt.--this invention relates to improvements in self-acting shackles and car brakes, and consists in an improved connection of the brakes with the shackle, for automatic operation, whereby the connection may be readily so adjusted that the brakes will not be set in action as when required to back up the train. feed bags for horses.--w. a. hough, south butler, n. y.--this invention relates to a new and useful improvement in feed bags for horses, and consists in making the bag self-supplying, by means of one or more reservoirs, the discharge orifices of which reservoirs are closed by a valve or valves. truss.--adam hinoult, montgomery, n. y.--this invention has for its object to furnish an improved truss, which shall be so constructed as to yield freely to the various movements of the body of the wearer, while holding the rupture securely in place. governor for steam engines.--charles a. conde, indianapolis, ind.--this invention relates to a new method of regulating the movement of the balls of a steam governor, with a view of adjusting the same in proportion to the increased or diminished centrifugal force. circular saw guard.--g. w. shipman, ischua, n. y.--this invention relates to a new and useful improvement in means for protecting the operator and others, near running circular saws, from injury, and it consists in a movable guard, operated by means of the saw carriage, in such a manner that, during the period of danger (when the saw is not cutting), the guard covers the saw, and is thrown back from the saw when the latter is in actual use. carpet-cleaning machine.--j. c. craft, baltimore, md.--this invention relates to a machine, through which a carpet may be passed, and so beaten and brushed, during its passage, as to come out of the machine thoroughly cleansed. the invention consists in the peculiar construction and arrangement of beaters and brushes for effecting this result. combined cotton and corn planter.--l. a. perrault, natchez, miss.--this invention relates to improvements in machinery for planting seed, and consists in a combination, in one machine, of a seed-dropping apparatus, adapted for corn, and another adapted for cotton, in a manner to utilize one running gear for the two kinds of seed, and thereby save the expense of separate gear for each. lime kiln.--t. a. kirk, kansas city, mo.--this invention has for its object to furnish an improved lime kiln, which shall be so constructed as to enable the kiln to be worked from the front, in firing and in drawing the lime and ashes, which will not allow cold or unburnt rock to pass through, and which will consume its own smoke. car brake.--s. d. tripp, lynn, and luther hill, stoneham, mass.--this invention relates to improvements in railroad car brakes, and consists in an arrangement, on the locomotive or tender, of a steam cylinder and piston, and the arrangement, on the cars, in connection with the brakes, of sliding rods, so that the rod of the car next to the engine or tender, being moved backwards by the piston rod of the above cylinder, will bring the brakes of the rear wheels down upon them, as well as the brakes of the tender, and slacken the speed thereby, so that the rear projecting end of the brake rod will come in contact with the rod of the next car, and set its brakes in action in like manner, and so on, throughout the train. the arrangement of the said brake actuating rods is such that no matter which end of the car is foremost, the wheels of one track will be acted on by the brakes. combined ruler, blotter, and paper cutter.--hugh s. ball, spartanburgh, s. c.--this invention relates to a new and useful improvement in a combined ruler, blotter, and paper cutter, three articles indispensable for the desk, combined in one. reed for organs and melodeons.--augustus newell, chicago, ill.--the object of this invention is to so construct the tongue-butts, or shanks, of musical reeds, that the same cannot, during the vibratory motion of the tongues, be raised from their seats. anti-friction compound.--victory purdy, poughkeepsie, n. y.--this invention relates to a new and useful compound for lubricating railroad car axle journals, and other journal bearings. * * * * * queries. [_we present herewith a series of inquiries embracing a variety of topics of greater or less general interest. the questions are simple, it is true, but we prefer to elicit practical answers from our readers, and hope to be able to make this column of inquiries and answers a popular and useful feature of the paper._] * * * * * .--emery wheels.--can i make emery wheels similar to those used in a foot lathe, that will answer for sharpening fine tools, such as gouges, rounds, and hollows, and if so, how shall i proceed?--f. w. .--boiler furnace.--i have two boilers, twenty-four feet long and four feet in diameter each, with five ten-inch flues. the fire passes under the boiler, and enters the flues at the back end, passes through the flues, and enters the smoke stack at the front end. i use hard pine wood for fuel. will some of your many readers give me the best way of constructing the flue under the boiler, from the end of the grate bars to where it enters the flues at the back end, and also state the proper distance from the back wall to the end of the boiler?--n. h. .--medal casts.--i have some medals which i should like to copy. having tried several times, and failed, i thought that i would ask advice through your query columns. i do not know of what the medals are manufactured. they are, i suppose, made to imitate bronze. i have tried casting them in plaster of paris molds, but have had very poor success, as the surface of the medals was covered with small holes. the metal used was lead and antimony, seven to one. i should like to know, if there be any metal that i can cast them of, and bring out the bronze color afterwards, or if there be any metal that i can cast them of, and afterwards color by some solution. also, of what should i make my molds?--j. e. m. .--removing the taste of tar from rain water.--will some of your correspondents tell me if rain water, which runs off a gravel roof, and tastes very strongly of tar, is unhealthy, and if there be anything that will prevent its tasting, as it is very disagreeable for cooking purposes?--c. e. h. .--sorghum molasses.--how can i separate the molasses from the sugar, in sorghum sugar mush, to make a dry merchantable sugar? .--flux for aluminum.--will some of your readers tell me, through your columns, the best flux to use in melting and mixing aluminum and copper? * * * * * inventions patented in england by americans. [compiled from the commissioners of patents' journal.] applications for letters patent. .--breech-loading fire-arms.--eli whitney, new haven, conn. february , . .--governor.--stilliman b. allen, ----, mass. february , . .--windmill.--a. p. brown, new york city. february , . .--furniture casters.--f. a. gardner and h. s. turrell, danbury conn. february , . .--wire fabrics for mattresses.--samuel rogers, new york city. february , . .--screw propeller canal boats.--thomas main, pierpoint, n. y. february , . .--flyer for spinning machinery.--thomas mayor and geo. chatterton, providence, r. i. february , . .--telegraphic apparatus and detectors.--w. b. watkins, jersey city, n. j. february , . .--steam and other safety valves.--walter dawson scranton, pa. february , . .--iron rails and bars, and modes of manufacturing the same.--eldridge wheeler, philadelphia, pa. february , . * * * * * official list of patents. issued by the u. s. patent office. for the week ending march , . _reported officially for the scientific american._ schedule of patent fees on each caveat $ on each trade-mark $ on filing each application for a patent, (seventeen years) $ on issuing each original patent $ on appeal to examiners-in-chief $ on appeal to commissioner of patents $ on application for reissue $ on application for extension of patent $ on granting the extension $ on filing a disclaimer $ on an application for design (three and a half years) $ on an application for design (seven years) $ on an application for design (fourteen years) $ _for copy of claim of any patent issued within years_ $ _a sketch from the model or drawing, relating to such portion of a machine as the claim covers, from_ $ _upward, but usually at the price above-named._ _the full specification of any patent issued since nov. , at which time the patent office commenced printing them_ $ . _official copies of drawings of any patent issued since , we can supply at a reasonable cost, the price depending upon the amount of labor involved and the number of views._ _full information, as to price of drawings, in each case, may be had by addressing_ munn & co., patent solicitors, park row, new york. * * * * * , .--hose sprinkler.--william anderson, san francisco, cal. , .--locomotive spark arrester.--j. g. armstrong, new brunswick, n. j. , .--tool for carriage makers' use.--george atkinson, san francisco, cal. , .--potato probe.--john a. beal, waterford, n. y. , .--hinge for carriage doors.--george w. beers, bridgeport, conn. , .--stove leg.--james birckhead, jr., baltimore, md. , .--clothes pin.--orris a. bishop, chicago, ill. , .--manufacture of rochelle salts and borax.--v. g. bloede, brooklyn, n. y. , .--beehive.--felix brewer, waynesville, mo. , .--thill coupling.--theodore burr (assignor to allen muir and henry muir), battle creek, mich. , .--evaporating pan for saccharine liquids.--f. c. butler, bellows falls, vt., assignor to himself and james b. williams, glastonbury, conn. , .--door securer.--william h. caldwell, wheeling, w. va. , .--toe-calk bar.--r. b. caswell, springfield, mass. antedated march , . , .--glass flattening furnace and leer.--james clabby, lenox, mass. , .--spring bed bottom.--alex. cole, manamuskin, n. j. , .--water wheel.--e. e. coleman, west cummington, mass. , .--toy horse and carriage.--john b. cuzner, bridgeport, conn. , .--mackerel-line holder.--e. l. decker, southport, me. , .--sewing machine.--j. william dufour, stratford, conn. , .--steam boiler.--edwards evans, north tonawanda, n. y. , .--medical compound for cure of catarrh and asthma.--erastus field, ostrander, ohio. , .--machine for grinding the cutters of mowers, etc.--h. c. fisk, wellsville, n. y. , .--machine for making hooks and eyes.--jeremy t. ford, san francisco, cal. , .--churn.--thompson freeman, westfield, ill. , .--attachment for revolving mold boards for plows.--j. s. godfrey, leslie, mich., assignor to himself and s. m. loveridge, pittsburgh, pa. , .--grain cleaner and fertilizer sifter.--j. a. green, mill dale, va. , .--screw propulsion.--e. c. gregg (assignor to a. h. gregg and c. p. gregg), trumansburg, n. y. , .--seeding machine.--p. m. gundlach, belleville, ill. , .--compound for kindling fires.--j. l. hannum and s. h. stebbins, berea, ohio. , .--lawn mower.--benjamin harnish, lancaster, and d. h. harnish, pequea, pa. , .--composition for pavements.--c. b. harris, new york city. antedated february , . , .--spring for vehicles.--john r. hiller, woodland, cal. , .--harvester rake.--s. t. holly, (assignor to john p. manny), rockford, ill. , .--door clamp.--henry o. hooper, diamond springs, cal. , .--taper holder.--thomas w. houchin, morrisania, n. y. , .--metallic garter.--henry a. house, bridgeport, conn. , .--bobbin winder.--henry a. house, bridgeport, conn. , .--method of knitting stockings, etc.--henry a. house, bridgeport, conn. , .--apparatus for evaporating and concentrating liquids.--john howarth, salem, mass. antedated march , . , .--apparatus for evaporating and concentrating liquids.--john howarth, salem, mass. antedated march , . , .--apparatus for removing oil from vegetable and other matters.--elias s. hutchinson, baltimore, md. , .--apparatus and process for removing oil from grain, seeds, etc.--elias s. hutchinson, baltimore, md. , .--chandelier.--charles f. jacobsen, new york city. , .--culinary vessel.--carrie jessup, new haven, conn. , .--machine for cutting leather.--aberdeen keith, north bridgewater, mass. , .--attaching knobs to their spindles.--john f. keller and nathaniel sehner, hagerstown, md. , .--miter machine.--t. e. king, boston, mass. , .--take-up for corset looms.--julius kuttner, new york city. , .--elevator and carrier.--t. w. lackore, worth, ill. , .--apparatus for burning hydrocarbon oils.--james r. lee, grass valley, cal. , .--burglar alarm.--robert lee, cincinnati, ohio. , .--telegraph apparatus.--l. t. lindsey, jackson, tenn. , .--harvester.--j. p. manny, rockford, ill. , .--harvester.--j. p. manny, rockford, ill. , .--harvester rake.--j. p. manny, rockford, ill. , .--cheese curd sink.--h. c. markham, collinsville, n. y. , .--mowing machine.--h. c. markham and dewitt c. markham, collinsville, n. y. , .--propeller.--alex. j. marshall, warrenton, va. antedated march , . , .--oiler.--edward mcduff and e. d. forrow, warwick, r. i. , .--wash boiler.--john mcinnes, oxford, pa. , .--propelling canal boats.--h. b. meech, fort edward, n. y. antedated february , . , .--water-proof compound for coating cloth wood, metals, etc.--peter e. minor, schenectady, n. y. , .--cooking stove.--w. n. moore, neenah, wis. , .--boring machine.--j. h. pardieck (assignor to himself and s. m. brown), acton, ind. , .--vapor burner.--r. w. park, philadelphia, pa. , .--machine for pointing blanks for cultivator teeth.--john pedder and george abel, west pittsburgh, pa. , .--bale tie.--j. e. perkins, san francisco, cal. , .--lining walls with felt, etc.--james phillips, chicago, ill. , .--cooking stove.--samuel pierce, boston, mass. , .--tack.--a. a. porter, new haven, conn. antedated feb. , . , .--machine for shaping and cutting gear cutters.--f. a. pratt (assignor to the pratt & whitney company), hartford, conn. , .--combination camera and developing box.--e. c. ratzell, philadelphia, pa. , .--punching machine.--j. c. rhodes, south abington, mass. , .--washing machine.--j. w. ricker, chelsea, mass. , .--curtain fixture.--charles robin. chester, conn. , .--machine for making printers' leads.--isaac schoenberg, new york city. , .--slide valve for steam riveting machines.--coleman sellers (assignor to william sellers & co.), philadelphia, pa. , .--machine for polishing thread.--samuel semple, sr., john semple, samuel semple, jr., and r. a. semple, mount holly, n. j. , .--paint brush.--f. s. shearer, washington, ill. , .--bee hive.--s. a. short, f. j. short, j. b. short, and jasper kile, decatur, ala. , .--apparatus for removing oil from vegetable and other matter.--thomas sim, baltimore, md. , .--retort for producing bisulphide of carbon.--thomas sim, baltimore, md. , .--utilizing the silky down of the wild cotton.--m. h. simpson, boston, mass. , .--pruning shears.--frank smiley, batavia, n. y. , .--water-closet valve.--a. j. smith, san francisco, cal. , .--gang plow.--j. w. sursa, san leandro, cal. , .--grinding pan and amalgamator.--w. h. thoss, west point, cal. , .--street lantern.--augustus tufts, malden, mass. , .--cooking stove.--alvin warren, swanton, ohio. , .--safety bridle.--james weatherhead, san josé, cal. , .--fire grate.--george wellhouse, akron, ohio. , .--hay knife.--g. f. weymouth, dresden, me. , .--claw bar.--charles winter, chillicothe, ohio. , .--steam generator.--j. c. woodhead, pittsburgh, pa. , .--animal trap.--w. d. wrightson, queenstown england. , .--brush.--john ames, lansingburg, n. y. , .--clod fender.--f. l. bailey, freeport, ind. , .--ruler.--h. s. ball, spartanburg, s. c. , .--fanning mill.--benjamin barney, time, ill. , .--ice-cutting machine.--lafayett barnum (assignor to himself and a. r. hale), bridgeport, conn. , .--manufacture of ice.--t. j. bigger, kansas city, mo. , .--machine for heading bolts and spikes.--reinhold boeklen, brooklyn, n. y., assignor to himself and henry torstrick new york city. antedated feb. , . , .--washing machine.--joseph boswell, l. m. boswell, jonathan palmer, and j. h. james (assignors to themselves and thomas starbuck), wilmington, ohio. , .--water wheel.--e. c. boyles, new york city. , .--cotton press.--r. m. brooks, pike county, ga. , .--paper-cutting machine.--samuel brown (assignor to himself and c. r. carver), philadelphia, pa. , .--governor for direct-acting engines.--a. s. cameron, new york city. , .--governor for direct-acting engines.--a. s. cameron, new york city. , .--butt hinge.--j. w. carleton (assignor to the union manufacturing co.), new britain, conn. , .--machine for cutting sheet metal.--c. r. choate, east saginaw, mich. , .--bit brace.--william cleveland, lawrence, mass., assignor to himself and james swan, seymour, conn. , .--steam engine governor.--c. a. condé, indianapolis, ind. , .--carpet-cleaning machine.--j. c. craft (assignor to himself and antonio rosello), baltimore, md. , .--steam regulator for paper dryers.--daniel crosby, hampden, me. .--metallic piston and valve rod packing.--g. m. cruickshank, providence, r. i. , .--grain-thrashing and separating machine.--john culham, grand rapids, mich. antedated feb. , . , .--cooking stove.--david curtis, mishawaka, assignor to himself and c. b. graham, south bend, ind. , .--lightning rod.--s. d. cushman, new lisbon, ohio. , .--hose bridge.--patrick daily (assignor to himself and j. j. kehoe), new york city. , .--cover for openings in sidewalks.--william dale, new york city. , .--rotary pump.--f. o. deschamps, philadelphia, pa. , .--machine for cutting files.--james dodge, manchester, england, assignor to david blake, spencertown, n. y. , .--coupling for railway cars.--henry dubs and s. g. goodall-copestake, glasgow, great britain. , .--tobacco pipe.--p. j. dwyer, elizabethport, n. j. , .--basket for house plants.--albert p. eastman, washington, d. c. , .--sulky plow.--milo a. elliott, stratford hollow, n. h. , .--stretcher for paintings.--james fairman, new york city. , .--body lantern holder.--samuel c. fessenden, stamford, conn. , .--stove leg.--amon l. finch, sing sing, n. y. , .--pump piston.--john s. follansbee and george doolittle (assignors to the forrester manufacturing company), bridgeport, conn. , .--shoe.--samuel w. francis (assignor to himself and w. h. newton), newport, r. i. , .--guard-finger for harvesters.--george fyfe and chester hard, ottawa, ill. , .--dining table.--s. r. gardner (assignor to himself and s. m. marquette), independence, iowa. , .--step ladder.--m. boland geary, new york city. , .--oilcloth printing machinery.--ebenezer a. goodes (assignor to philadelphia patent and novelty company), philadelphia, pa. , .--tenoning machine.--lyman gould, norwich, conn. , .--printer's case.--wm. h. a. gresham, atlanta, ga. , .--lamp chimney.--geo. w. griswold, factoryville, pa. , .--grain separator.--philander griswold, hudson, mich. , .--clamp for thill couplings.--john w. guider (assignor to himself and john kiefer), st. joseph, mo. , .--bird cage.--gottlob gunther, new york city. , .--stop cock and valve.--william haas, new york city. , .--valve for steam engines.--joseph l. harley, baltimore, md., and xaver fendrich, georgetown, d. c. , .--metallic hub.--john h. harper, pittsburgh, pa. , .--composition for lubricating machinery.--e. q. henderson (assignor to john c. burroughs and richard a. springs) charlotte, n. c. , .--post-hole digger.--bryant b. herrick, decatur, mich. , .--door check.--levi s. hicks (assignor to himself, j. perrin johnson, and john buell), peoria, ill. , .--railway-car brake.--luther hill, stoneham, and seth d. tripp, lynn, mass. , .--truss.--adam hinoult, montgomery, n. y. , .--feed bag for horses.--walter a. hough, south butler, n. y. , .--shade holder for lamps--mark w. house, cleveland, ohio. , .--lamp chimney.--mark wiggins house (assignor to the cleveland non-explosive lamp company), cleveland, ohio. antedated march , . , .--horse hay rake.--james howard and e. t. bousfield, bedford, england. , .--tongs for rolling barrels.--mark w. ingle, indianapolis, ind. , .--pitman.--george w. jayson, lodi, ohio. , .--paste for paper hangings.--john jones (assignor to himself and henry a. smith), new york city. , .--twine holder.--edward m. judd, new haven, ct. , .--clothes pin or clasp.--amos l. keeports and william yount, littletown, pa. , .--putting up hams.--samuel edward kelly, philadelphia, pa. , .--limn kiln.--thomas a. kirk, kansas city, mo. , .--fastening for seats for wagons or sleighs.--john g. knapp and john f. robertson (assignors of one third their right to james h. holly), warwick, n. y. , .--potato planter.--george knowlton (assignor for one-half his right to n. haynes), johnstown, pa. , .--revolving firearm.--edwin s. leaycroft, brooklyn, n. y., assignor by mesne assignment, to "colt's patent firearms manufacturing company," hartford, conn. , .--revolving firearm.--edwin s. leaycroft, brooklyn, n. y., assignor, by mesne assignment, to "colt's patent firearms manufacturing company," hartford, conn. , .--railroad cattle-guard gate.--j. h. mallory, la porte, ind. , .--back-reflecting mirror.--richard mason (assignor to himself and matthew ely), newark, n. j. , .--ventilator and chimney top.--james mcgowan (assignor to himself and daniel h. waring), new york city. , .--apparatus for rectifying and refining spirits.--frederick measey (assignor to himself and henry d. fling), philadelphia, pa. , .--tin can.--john f. merrill (assignor to himself and alexander stewart), cincinnati, ohio. , .--take-up mechanism for looms.--john michna and joseph fischer, new york city. , .--combined baker and broiler.--wm. h. miller, brandenburg, ky. , .--shuttle for sewing machines.--james d. moore, grinnell, iowa. , .--cotton chopper and grain cultivator.--daniel mosely, osark, arkansas. , .--sad and fluting iron.--frederick myers, new york city. , .--reed for organs and melodeons.--augustus newell, chicago, ill. , .--straw cutter.--amon park, germanville, iowa. , .--apparatus for aging whisky and other spirits.--josiah peiffer and samuel richards, valonia, pa. , .--combined cotton and corn planter.--louis a. perrault (assignor to himself and joseph huber), natchez, miss. , .--faucet.--solomon pfleger, reading, assignor to himself and j. s. pfleger, tamaqua, pa. , .--treadle.--george k. proctor, salem, mass. , .--lubricating compound.--victory purdy, poughkeepsie, n. y. , .--fertilizer and seeding machine.--archibald putnam (assignor to elizabeth putnam), owego, n. y. , .--rotary pump.--george w. putnam, south glens falls, n. y. , .--hat brush.--robert dunbar radcliffe, palmyra, n. y. , .--refrigerating show case.--thomas l. rankin, lyndon, kansas, assignor to himself and d. w. rockwell, elyria, ohio. , .--device for starting and stopping cars.--philip rhoads, carlisle, pa. , .--pipe-molding machine.--george richardson, milwaukee, wis. , .--sulky cultivator.--richard b. robbins, adrian, mich. , .--hand plow.--nelson rue, harrodsburg, ky. , .--mechanical movement.--edward g. russell, ravenna, ohio. , .--railway car brake.--lyman alphonzo russell, shrewsbury, vt. , .--stovepipe cleaner.--david sanford, ashton, ill. , .--twine holder.--joseph b. sargent and purmont bradford (assignors to sargent & co.), new haven, conn. , .--dovetailing machine.--james m. seymour, newark, n. j. , .--wooden pavement.--eaton shaw, portland, me. , .--guard for circular saws.--george w. shipman, ischua, n. y. , .--breech-loading firearm.--dexter smith and martin j. chamberlin, springfield, mass. , .--spark arrester.--james smith, altoona, pa. , .--horse hay rake.--solomon p. smith, waterford, n. y. , .--plow.--s. m. stewart, new harrisburg, ohio. , .--medical compound for treating fever and ague.--george e. swan, mount vernon, ohio. , .--device for cooling journals of car axles.--henry g. thompson, milford, conn. , .--cooling journal of car axles.--henry g. thompson, milford, conn. , .--cooling journal of car-wheel axles.--henry g. thompson, milford, conn. , .--device for cooling journals of railway cars.--henry g. thompson, milford, conn. , .--non-heating handle for sad irons, etc.--william h. towers, boston, mass. , .--lubricator.--john erst uhl, renovo, pa. , .--combined corn planter and cultivator.--franklin underwood, south rutland, n. y. , .--king bolt.--wendel vondersaar, indianapolis, ind. , .--wheat roaster.--george w. waitt (assignor to himself and robert b. fitts), philadelphia, pa. , .--plaster sower.--thomas j. west, alfred center, n. y. , .--ticket holder.--henry wexel, providence, r. i. , .--tobacco press.--abraham n. zell, lancaster, pa. , .--combined bag holder and scales.--william zimmerman, lebanon, pa. antedated february , . , .--breech-loading firearm.--james m. mason, washington, d. c. * * * * * reissues. , .--treating fruits to dry, saccharify, and preserve them.--charles alden, newburg, assignor of part interest to alden fruit preserving company, new york city. patent no. , , dated march , ; reissue no. , , dated june , . , .--device for securing pulleys to shaft.--john h. buckman (assignor to himself and peter w. reinshagen), cincinnati, ohio. patent no. , , dated december , . , .--shawl strap.--george crouch, westport, conn. patent no. , , dated september , . , .--atmospheric dental plate.--nehemiah t. folsom, laconia, n. h. patent no. , , dated january , . , .--pessary.--william r. gardner, leonardsville, n. y. patent no. , , dated july , . , .--division a.--skate.--james l. plimpton, new york city. patent no. , , dated january , ; reissue no. , , dated april , . , .--division b.--skate.--james l. plimpton, new york city. patent no. , , dated january , ; reissue no. , , dated april , . , .--apparatus for pitching barrels.--louis schulze, baltimore, md. patent no. , , dated august , . * * * * * designs. , .--picture frame.--john h. bellamy, charlestown, mass. , .--bell crank and escutcheon.--pietro cinquini, west meriden, conn., assignor to parker & whipple company. , .--pedestal for a cake dish.--george gill (assignor to reed & barton), taunton, mass. , .--table caster.--william parkin (assignor to reed & barton), taunton, mass. , .--buckle frame.--john e. smith, waterbury, conn. , .--back of a chair or sofa.--george unverzagt, philadelphia, pa. * * * * * trade-marks. .--hat.--nathan a. baldwin, milford, conn., james h. prentice, brooklyn, and john r. waller, new york city. .--spool cotton.--lewis coleman & co., boston, mass. .--salve.--robert dobbins, binghamton, n. y. .--soap.--leberman & co., philadelphia, pa. .--medicine.--ridenour, coblentz & co., springfield, ohio. .--paper.--union manufacturing company, springfield, mass. * * * * * extensions. wagons.--edgar huson, ithaca, n. y. letters patent no. , , dated february , ; reissue no. , , dated march , . operating valve of steam engine.--samuel r. wilmot, bridgeport, conn. letters patent no. , , dated february , . hinges.--john david browne, cincinnati, ohio. letters patent no. , , dated february , . keeper for right and left hand door locks.--calvin adams, pittsburgh, pa. letters patent no. , , dated february , . solar camera.--david a. woodward, baltimore, md. letters patent no. , , dated february , ; reissue no. , , dated july , . cast seamless thimble skeins for wagons.--john benedict, kenosha, wis., administrator of andrew leonard, deceased. letters patent no. , , dated february , ; reissue no. , dated july , ; reissue no. , , dated october , . mode of casting seamless skeins for wagons.--john benedict, kenosha, wis., administrator of andrew leonard, deceased. letters patent no. , , dated february , ; reissue no. , dated july , ; reissue no. , , dated october , . breech-loading firearms.--william cleveland hicks, summit, n. j. letters patent no. , , dated march , ; reissue no. , , dated may , ; reissue no. , , dated january , ; reissue no. , , dated march , . seeding machine.--lewis b. myers and henry a. myers, elmore, ohio. letters patent no. , , dated march , . * * * * * disclaimer. solar camera.--david a. woodward, baltimore, md. letters patent no. , , dated february , ; reissue no. , , dated july , . filed february , . * * * * * city subscribers.--the scientific american will be delivered in every part of the city at $ . a year. single copies for sale at the news-stands in this city, brooklyn, jersey city, and williamsburgh, and by most of the news dealers in the united states. * * * * * receipts--when money is paid at the office for subscriptions, a receipt for it will be given; but when subscribers remit their money by mail, they may consider the arrival of the first paper a bona-fide acknowledgment of their funds. * * * * * advertisements. * * * * * _the value of the_ scientific american _as an advertising medium cannot be over-estimated. its circulation is ten times greater than that of any similar journal now published. it goes into all the states and territories, and is read in all the principal libraries and reading-rooms of the world. we invite the attention of those who wish to make their business known to the annexed rates. a business man wants something more than to see his advertisement in a printed newspaper. he wants circulation. if it is worth cents per line to advertise in a paper of three thousand circulation, it is worth $ . per line to advertise in one of thirty thousand._ rates of advertising. back page - - - - . a line, inside page - - - cents a line, _for each insertion_. _engravings may head advertisements at the same rate per line, by measurement, as the letter-press_. * * * * * to manufacturers of knitted goods. john kent is now in england, completing arrangements so as to be able to supply his american friends with his improved knitting machines with greater dispatch, and with all the latest improvements. he would beg to call especial attention to the improved rib top frame, now so well known, and acknowledged to be the best rib top frame ever built, for speed and quality of goods produced. price, delivered free in new york, $ , currency. the improved circular web frame, for drawers and shirts, built of any size and gage. price for a -head set, inch to inch diameter, $ , currency, delivered free in new york. the circular stocking frame, from in. to ½ in. diameter. these circular frames, with my last improvements, are as near perfection as possible. the patent full-fashioned shirt, drawers and stocking frames produce the most perfect goods ever made by steam-power machinery, and cost fifty per cent less to keep in repair than any other knitting machine. built to gage, and from to inch wide, to order. the improved circular looping frame, for putting on shirt cuffs, drawers bands, clearing the top of circular shirts, &c., built to order, of any size, from in. to in. diameter, and of any gage. steel needles and sinkers to pattern. persons wishing to order while mr. kent is in england, will please address john kent, nottingham, up to april th, or, if they prefer, may send through depot. address john kent, pearl st., new york. * * * * * pumps.--for description, price lists etc., of the best centrifugal pump ever invented, with overwhelming testimony in its favor, send for new illustrated pamphlet ( pp.) to messrs. heald, sisco & co., baldwinsville, n. y. * * * * * brick presses. for red and fire brick. factory s. fifth street, philadelphia, pa. s. p. miller. * * * * * st. joseph, mo., nov. , . t. r. bailey & vail, lockport, n. y.: gentlemen:--the lathe you shipped me has arrived, and i have it in full operation. it works perfectly, and i think it the best lathe made in the world for bedstead and chair work. i would recommend it to any one desirous of obtaining such a lathe. yours truly, h. r. bristol. * * * * * woolen mill for sale. with house and acres of land, seymour, ct., (naugatuck valley,) miles from r. r. depot. never-failing stream. ft. fall, dam and wheel in good condition. inquire of jas. ormsbee, on the premises. * * * * * portable & stationary steam engines and hoisting engines. a good article at low prices. every machine warranted. send for descriptive price list. h. b. bigelow & co., new haven, conn. * * * * * patent bandsaw machines [illustration] of the most approved kinds, of various sizes, to saw bevel as well as square, without inclining the table, by first & pryibil, to tenth ave., new york. price $ , $ , $ , and $ . at present (oct. ), there are in operation, in this city alone, of our machines. send for circular. manufacture, also, an improved saw-filing apparatus; price, $ . have also on hand a large stock of best french bandsaw blades. * * * * * l. & j. w. feuchtwanger, cedar st., new york, chemists, manufacturers, and importers of specialities, silicates, soda and potash, chloride of calcium, peroxide of manganese, hydrofluoric acid, metallic oxides, steel and glass makers' and potters' articles, publishers of treatises on "soluble glass," "gems," and "fermented liquors." * * * * * pimlico braces, something new. this invention is based on a strictly scientific principle, and is a valuable improvement on old style suspenders. it is simple in construction, and combines the qualities of brace and suspender. they are unequaled for elegance, durability and comfort. manufactured at the monumental silk works, baltimore. john m. davies & co., sole agents, & b'd'y, n. y. * * * * * dr. j. armstrong's (patent) improved heater, filter, lime extractor, and condenser combined, for steam boilers. [illustration] manufactured by armstrong & starr, toledo, ohio. _send for circulars._ formerly armstrong & welsh. * * * * * for sale.--an engine, × in. cylinder, and two boilers, × feet, in good order, will be sold cheap. j. j. taylor & co., courtlandt st., new york. * * * * * hunting, trapping and fishing. all about it. sent free. address "hunter," hinsdale, n. h. * * * * * first premium awarded by am. inst., microscopes, } illustrated price list and catalogues magic lanterns, } free to any address. t. h. mcallister, optician, nassau st., n. y. * * * * * rare and beautiful flowers --and-- choice vegetables can always be obtained by sowing [illustration: bliss's select garden seeds.] bliss's select garden seeds. the seventeenth annual edition of their celebrated "seed catalogue and guide to the flower and kitchen garden," is now ready for distribution. it contains four beautifully colored lithographs, and about choice engravings of favorite flowers and vegetables, pages of closely-printed matter, and a list of twenty-five hundred species and varieties of flower and vegetable seeds, with explicit directions for their culture, and much other useful information upon the subject of gardening. a copy will be mailed to all applicants inclosing cts. regular customers supplied gratis. address b. k. bliss & sons, nos. park place, and murray st., p. o. box no. . new york. * * * * * science for the million. the boston journal of chemistry, devoted to the science of home life, the arts, agriculture, and medicine. james r. nichols, m. d.,} william a. rolfe, a. m.,} editors. one dollar per year. a paper which commends itself at once to physicians, druggists, chemists, teachers, farmers, mechanics--in short, to professional and practical men of every class. the domestic recipes and formulæ for art processes are of themselves worth many times the cost of subscription. ---> specimen copies sent free. address boston journal of chemistry, congress st., boston. * * * * * foot lathes, and all kinds of small tools. illustrated catalogue free. goodnow & wightman, cornhill, boston, mass. * * * * * agents wanted.--to sell stephens' patent combination rule, which embraces a rule, level, square, plumb, bevel, slope level, t square, etc., in one compact tool. these instruments retail at $ . each, and energetic salesmen can make money by selling them among mechanics. we warrant them in every particular, as the construction and graduation is faultless. send for descriptive circular, cuts, and terms. stephens & co., riverton, conn. * * * * * felt. the best, cheapest and most durable non-conductor known, for sale by the original manufacturer, at the boiler felting works, courtland st., new york. * * * * * universal wood worker. for agricultural, railroad, car, carriage, and wagon works, planing mill, sash, door and blind, bedstead, cabinet and furniture factories. mcbeth, bentel & margedant, hamilton, o. * * * * * inventor's exchange, broadway, n. y., "am. agriculturist" building. tangible inventions negotiated. no goods received unless ordered. b. f. kemp, proprietor. * * * * * machinists' tools, at greatly reduced prices. also, some woodworth planers and second-hand tools. to r. r. ave., newark, n. j. e. & r. j. gould, successors to gould machine co. * * * * * n. b. patented articles introduced. also, state and county rights sold for inventors. stone, pugh & co., n. th st., philadelphia. * * * * * golden hill seminary for young ladies, bridgeport, conn. miss emily nelson, principal. * * * * * use the vegetable pulmonary balsam. the old standard remedy for coughs, colds, consumption. "nothing better." cutler bros. & co., boston. * * * * * the calvert iron rolling mills are offered at private sale. these mills are situated in the city of baltimore, and cover ½ acres of ground. the machinery is of the most approved description, for making all sizes of round and square bar iron, from ¼ in. to in. diameter, and flat bars of all widths, up to inches. the buildings are ample and commodious. in addition to the rolling mills are two brick buildings ( × feet and × feet), now containing an h. p. engine, and spike machinery, but which could be used for the manufacture of nails, horseshoes, or any other branch of heavy hardware. this property offers an unusual opportunity to capitalists, and will be sold at a reasonable price. for further description address marshall p. smith, p. o. box , baltimore, md. * * * * * burdon iron works.--manufacturers of pumping engines for water works, high & low pressure engines, portable engines and boilers, of all kinds, sugar mills, screw, lever, drop, & hydraulic presses, machinery in general. hubbard & whittaker, front st., brooklyn. * * * * * engines and machinery for sale, at a great sacrifice. two new steam engines, and horse power; faribain's riveting machine; large power shears; ditto table punch; ditto flange punches; set power bending rolls; together with a large lot of turning lathes, drilling machines, machinists' and smiths' hand tools, pulleys, hangers, and fairbanks' platform scales. send for catalogue, or apply at the south brooklyn steam engine works, cor. imlay and summit sts., brooklyn. * * * * * shingle and heading machine-- law's patent with trevor & co.'s improvements. the simplest and best in use. also, shingle, heading and stave jointers, equalizers, heading turners, planers etc. address trevor & co., lockport, n. y. * * * * * agents wanted--($ a month) by the american knitting machine co. boston, mass., or st. louis, mo. * * * * * the _united states_ brick machine is the best in the world, because it makes the greatest number, the best, and the cheapest bricks. it is the perfection of simplicity. it is durable, and not likely to get out of repair. see scientific american, sept. , . for descriptive circular apply to f. c. wells, president, room , madison st., chicago. machines can be seen in operation at the company's works, chicago; at rear ann st., new york city; and at novelty iron works, corner of delord and peter sts., new orleans. * * * * * prepared asphalte roofing felt. [illustration] this new prepared production is ready coated, and can be applied on the roof without further trouble. it is easy of application, and does not require any repairs for a long time. it is more durable than some slates, and has been found a suitable substitute for iron or tin roofs. it has a sanded or stony surface, which renders it uninflammable and fire-proof. exposed to the most intense fire, and sparks falling upon it, it will not propagate the fire. under the influence of the sun it will not run, which makes it specially adapted to hot climates. its easy application and pleasing appearance have made it a favorite roofing material throughout all the indies and other colonies. being not cumbrous for transport, it is of invaluable service to settlers and farmers in far remote districts. when used for temporary purposes it may be taken off and applied again to another construction. it replaces common asphalting on terraces, lobbies, counting-houses, office floors, etc.; is a great preservative against dampness and vermin, and equalizes the temperature. it is inches wide, and made in rolls of yards each. send for circular to e. h. martin, maiden lane and liberty st., n. y. * * * * * j. j. h. gregory's seed catalogue. my annual illustrated catalogue, containing a list of many new and rare vegetables, some of which are not found in any other catalogue, and all the standard vegetables of the farm and garden (over one hundred of which i grow on my three seed farms), with a carefully selected list of flower seed, will be sent free to all. all my seed is sold under three warrants: st. that all money sent shall reach me. d. that all seed ordered shall reach the purchaser. d. that my seeds shall be fresh and true to name. james j. h. gregory, marblehead, mass. * * * * * the new wilson under-feed shuttle sewing machines! $ cheaper than any other! [illustration] for simplicity, durability and beauty they stand _unrivalled!_ for stitching, hemming, tucking, felling, quilting, cording, binding, braiding, gathering, gathering & sewing on gathers, _they are unexcelled!_ for particulars address wilson sewing machine co., cleveland, o., or st. louis, mo. agents wanted. * * * * * machinery, new and d-hand.--send for circular. chas. place & co., vesey st., new york. * * * * * machinists. illustrated catalogue and price list of all kinds of small tools and materials sent free to any address. goodnow & wightman, cornhill, boston, mass. * * * * * p. blaisdell & co. manufacturers of the "blaisdell" patent drill presses, with quick return motion, agricultural drills, improved engine lathes, from in. to in. swing, planers, gear cutters, boring mills, hand lathes, and other first-class machinists' tools. jackson st., worcester, mass. * * * * * patent bedstead fastening. the best, cheapest, and strongest fastening ever invented. rights for states and territories for sale. address john domingos and benjamin essig, sacramento, cal. * * * * * bent, goodnow & co., boston, mass., publishers of "patent star", sell patent rights and goods of all kinds. orders solicited. agents wanted. ---> send stamp for copy. * * * * * to the working class.--we are now prepared to furnish all classes with constant employment at home, the whole of the time or for the spare moments. business new, light and profitable. persons of either sex easily earn from c. to $ per evening, and a proportional sum by devoting their whole time to the business. boys and girls earn nearly as much as men. that all who see this notice may send their address, and test the business, we make this unparalleled offer: to such as are not well satisfied, we will send $ to pay for the trouble of writing. full particulars, a valuable sample which will do to commence work on, and a copy of _the people's literary companion_--one of the largest and best family newspapers published--all sent free by mail. reader, if you want permanent, profitable work, address d. c. allen & co., augusta, maine. * * * * * _important_ to machinists.--the best metal for all machine uses is the martin steel, made by the new jersey steel and iron co., trenton, n. j. this steel is made by an entirely different process from any other and is tougher than wrought iron. it can be turned without annealing, being entirely free from hard spots. every one who uses it pronounces it just what they have long wanted, for a multitude of uses, such as crank pins, lathe spindles and screws, cotton machinery rollers, saw and fan spindles, etc., etc. also, particularly adapted for firebox plates. prices low. send for further information, or a sample, stating use to which it is to be applied. * * * * * otis' safety hoisting machinery. otis, bros. & co. no. broadway, new york. * * * * * [illustration: trade mark.] union emery wheels. solid and with stone center. union stone co., boston, mass. branch office, liberty st., n. y. general agents for the am. twist drill co.'s superior grinder and other emery wheel machinery and tools. send for circular. * * * * * woodbury's patent _planing and matching_ and molding machines, gray & wood's planers, self-oiling saw arbors, and other wood working machinery. s. a. woods, { liberty street, n. y.; send for circulars. { sudbury street, boston. * * * * * richardson, meriam & co., manufacturers of the latest improved patent daniels' and woodworth planing machines, matching, sash, and molding, tenoning, mortising, boring, shaping, vertical, and circular re-sawing machines, saw mills saw arbors, scroll saws, railway, cut-off, and rip-saw machines, spoke and wood turning lathes, and various other kinds of wood-working machinery. catalogues and price lists sent on application. manufactory, worcester, mass. warehouse, liberty st., new york. * * * * * [illustration] reynolds' turbine water wheels. the oldest and newest. all others only imitations of each other in their strife after complications to confuse the public. we do not boast but quietly excel them all in staunch reliable, economical power. beautiful pamphlet free. geo. tallcot, liberty st., new york. gearing, shafting. * * * * * _niagara steam pump._ chas. b. hardick, adams st., brooklyn, n. y. * * * * * models, patterns, experimental, and other machinery, models for the patent office, built to order by holske machine co., nos. , , and water st., near jefferson. refer to scientific american office. tf * * * * * . schenck's patent. . woodworth planers. and re-sawing machines, wood and iron working machinery, engines, boilers, etc. john b. schenck & son, matteawan, n. y., and liberty st., new york. * * * * * wanted--agents, $ per day, to sell the celebrated home shuttle sewing machine. has the under-feed, makes the "lock stitch" alike on both sides, and is fully licensed. the best and cheapest family sewing machine in the market. address johnson, clark & co., boston, mass.; pittsburgh, pa.; chicago, ill., or st. louis, mo. * * * * * milling machine, index, standard, universal, and horizontal.--the largest variety to be found in the country, on hand and finishing. workmanship, material, and design unsurpassed. machines on exhibition at fair of american institute. union vise co. of boston. office milk st. works at hyde park, mass. * * * * * _andrew's patents._ noiseless, friction grooved, portable, and warehouse hoisters. friction or geared mining & quarry hoisters. smoke-burning safety boilers. oscillating engines, double and single, - to -horse power. centrifugal pumps, to , gallons per minute, best pumps in the world, pass mud, sand, gravel, coal, grain, etc., without injury. all light, simple, durable, and economical. send for circulars. wm. d. andrews & bro., water street, new york. * * * * * $ a month! employment! extra inducements! a premium horse and wagon for agents. we desire to employ agents for a term of seven years, to sell the buckeye $ . shuttle sewing machine. it makes a stitch alike on both sides, and is the best low-priced licensed machine in the world. w. a. henderson & co., cleveland, ohio, or st. louis, mo. * * * * * allcott's lathes, for broom, hoe, and rake handles, for sale by l. w. pond, liberty st., new york. * * * * * unrivalled hand saw mill, self-feeding, with ease. rip -in. lumber; guaranteed do work of men. the only hand saw machine known, does as represented. thousands in use. send for circular. wm. h. hoag, sole manufacturer, pearl st. n. y. * * * * * u. s. piano co. n. y. best in the world--$ . sent on trial--see large cut and terms in scientific american. oct. st . * * * * * _dovetailing machine._ will make drawers per day. see scientific american, jan. , ' . h. h. evarts, liberty st.; trevor & co., lockport n. y. * * * * * circular saw mills. hays & newman's patent double parallel edgers, foster's patent log-canting machines, and sawmill machinery generally, manufactured by the washington mowing machine company. leroy mowry, agent, sandy hill, wash. co., n. y. send for illustrated circulars and price lists. * * * * * _to electro-platers._ batteries, chemicals, and materials, in sets or single, with books of instruction, manufactured and sold by thomas hall, manufacturing electrician, bromfield street, boston, mass. illustrated catalogue sent free on application. * * * * * prize medal scroll saw.-- thos. l. cornell, derby, conn. * * * * * patent rights sold on commission. by e. e. roberts & co., consulting engineers, wall st., n. y. send stamp for circular. * * * * * newspaper advertising. a book of closely printed pages, lately issued, contains a list of the best american advertising mediums giving the names, circulations, and full particulars concerning the leading daily and weekly political and family newspapers, together with all those having large circulations, published in the interest of religion, agriculture, literature, etc., etc. every advertiser, and every person who contemplates becoming such, will find this book of great value. mailed free to any address on receipt of c. geo. p. rowell & co., publishers, no. park row, new york. the pittsburgh (pa.) leader, in its issue of may , says: "the firm of g. p. rowell & co., which issues this interesting and valuable book, is the largest and best advertising agency in the united states, and we can cheerfully recommend it to the attention of those who desire to advertise their business scientifically and systematically in such a way: that is, so as to secure the largest amount of publicity for the least expenditure of money." * * * * * the celebrated _cold-rolled shafting._ this shafting is in every particular superior to any turned shafting ever made. it is the most economical shafting to buy, being so very much stronger than turned shafting. less diameter answers every purpose, causing a great saving in coupling, pulleys and hangers. it is perfectly round, and made to whitworth gage. all who give it a trial continue to use it exclusively. we have it in large quantities. call and examine it, or send for price list. address george place & co., and chambers st., new york. * * * * * _n. y. machinery depot._ george place & co., manufacturers and dealers in wood and iron working machinery, of every description, stationary and portable engines and boilers, leather and rubber belting, and all articles needful in machine or railroad repair shops. and chamber st., new york. * * * * * _sturtevant blowers._ these are in every particular the best and most perfect blower ever made. a full assortment of every size on hand, ready to deliver. address george place & co., and chamber st., new york. * * * * * [illustration: wrought iron beams & girders] the union iron mills, pittsburgh, pa. the attention of engineers and architects is called to our improved wrought-iron beams and girders (patented), in which the compound welds between the stem and flanges, which have proved so objectionable in the old mode of manufacturing, are entirely avoided, we are prepared to furnish all sizes at terms as favorable as can be obtained elsewhere. for descriptive lithograph address carnegie, kloman & co., union iron mills, pittsburgh, pa. * * * * * mill owners, attention.--our turbine water wheels still ahead. no complications. simple, compact, and durable. prices moderate. valentine & co., ft. edward, n. y. * * * * * the woodward steam-pump manufacturing company, manufacturers of the woodward pat. improved safety steam pump and fire engine, steam, water, and gas fittings of all kinds. also dealers in wrought-iron pipe, boiler tubes, etc. hotels, churches, factories, & public buildings heated by steam. low pressure. woodward building, and center st., cor. of worth st. (formerly of beekman st., n. y.) all parties are hereby cautioned against infringing the pat. right of the above pump. g. m. woodward, pres't. * * * * * buerk's watchman's time detector.--important for all large corporations and manufacturing concerns--capable of controlling with the utmost accuracy the motion of a watchman or patrolman, as the same reaches different stations of his beat. send for a circular. j. e. buerk, p. o. box , boston, mass. n. b.--this detector is covered by two u. s. patents. parties using or selling these instruments without authority from me will be dealt with according to law. * * * * * portable steam engines, combining the maximum of efficiency, durability and economy, with the minimum of weight and price. they are widely and favorably known, more than being in use. all warranted satisfactory or no sale. descriptive circulars sent on application. address j. c. hoadley & co., lawrence, mass. . cortlandt st., new york. * * * * * $ to $ per day. men, women, boys and girls who engage in our new business make from $ to $ per day in their own localities. full particulars and instructions sent free by mail. those in need of permanent, profitable work, should address at once. george stinson & co., portland, maine. * * * * * _agents! read this!_ we will pay agents a salary of $ per week and expenses, or allow a large commission, to sell our new and wonderful inventions. address m. wagner & co., marshall, mich. * * * * * epilepsy or fits. a sure cure for this distressing complaint is now made known in a treatise of octavo pages, on foreign and native herbal preparations, published by dr. o. phelps brown. the prescription was discovered by him in such a providential manner that he cannot conscientiously refuse to make it known, as it has cured everybody who has used it for fits, never having failed in a single case. the ingredients may be obtained from any druggist. persons desiring a copy may address dr. o. phelps brown, no. grand street, jersey city, n. j., and it will be sent by return mail. * * * * * wood-working machinery generally. specialties, woodworth planers and richardson's patent improved tenon machines. nos. and central, corner union st., worcester, mass. warerooms cortlandt st., new york. witherby rugg, & richardson. * * * * * cincinnati brass works.--engineers and steam fitters' brass work, best quality at very low prices. f. lunkenheimer, prop'r. * * * * * hinkley knitting machine. the simplest, cheapest, and best in use. has but one needle! a child can run it! agents wanted in every town. send for circular and sample stocking to hinkley knitting machine co., bath, me. * * * * * lathe chucks--horton's patent from to inches. also for car wheels. address e. horton & son, windsor locks, conn. * * * * * silicate of soda, in its various forms, manufactured as a specialty, by philadelphia quartz co., south d st. philadelphia, pa. * * * * * advertisements. _advertisements will be admitted on this page at the rate of $ . per line for each insertion. engravings may head advertisements at the same rate per line, by measurement, as the letter-press._ * * * * * _an important fact._ marvin & co.'s spherical safes have never been robbed. hundreds are in use by banks, bankers, and merchants. { broadway, new york. { chestnut st., philadelphia. warehouses, { bank st., cleveland. { main st., buffalo. * * * * * l: l: smith & co., nickel platers, howard st., new york, between elm and centre. * * * * * _save your fuel._ [illustration] the original l. b. tupper's furnace grate bar. guaranteed to make from to lbs. more steam, with less fuel, than any other bar. adapted to all kinds of fuel; no alteration of furnace required. received silver medal at cincinnati industrial exposition, ; silver medal at worcester co. mechanics' association, ; medal and diploma at american institute fair, ; honorable mention at paris exposition. send for descriptive pamphlet. now in use in , places. l. b. tupper, west st., new york. * * * * * [illustration] pyrometers. for blast furnaces, bakers' ovens, boiler flues, superheated steam oil stills, zinc and lead baths. e. brown, walnut st., philadelphia. * * * * * _agents wanted._ to sell the universal sash lock. it is self-acting and burglar-proof. send stamp for circulars. carpenters and builders can make from $ to $ selling them. address g. s. lacey, care of patterson brothers, no. park row, new york city. * * * * * sperm oil, _strictly pure_, for sewing machines and fine machinery, in bottles and bbls. sample by mail, cts. w. f. nye, new bedford, mass. * * * * * _the reasons why_ dooley's yeast powder is preferred to any other baking powder in market, are owing to its perfect purity, quality, quantity, and economy. the ingredients are strictly free from deleterious substances, and hence the full strength of each is obtained, and the results are uniform every time it is used. this cannot be the case in those of ordinary manufacture, and for proof of our assertion, we ask those who have never used dooley's yeast powder to give it a trial. your grocer keeps it. dooley & brother, manufacturers, new st., new york. * * * * * patent cutters for the teeth of gear wheels, which can be sharpened by grinding, without changing their form. cutters made on this plan will last many times as long as those of the common form, with the advantage of being always ready for use. descriptive circular, with price list, sent per mail on application. brown & sharpe m'f'g co., providence, r. i. * * * * * a spring of water at the top of the house. houghton's automatic water elevator, patented feb. , , no. , , delivers water from the well or cistern in the tank at the top of the house. is operated by the fire in the kitchen range without additional fuel; is simple in construction, reliable and cheap. reliable parties wanted to introduce them into use in all the states except new england. for drawings and full description address charles houghton, state st., boston, mass. * * * * * short hand.-- words per minute in four weeks. send stamp for circular. prof. gray, p. o. box , new york. * * * * * watches that are watches. we shall be pleased to send our descriptive price list of genuine waltham watches, together with an illustrated pamphlet entitled a history of watchmaking, to all who send us their address. no matter how remote you are from new york, we can sell you a watch at the same price as if you were here. when you write mention that you saw this notice in the scientific amer. howard & co., broadway, n. y. * * * * * engines, tools, machinery, etc., for sale at the novelty iron works, foot of east th street, new york city, embracing engines, planers, lathes, smith and boiler makers' tools, and machinery and patterns of the most approved kinds, etc. also, high pressure engine, -inch diameter by -inch stroke: stevenson's patent turbine water wheels, -inch diameter, and marine beam engine, -inches by -feet stroke. send for catalogue. jno. s. schultze, receiver of the novelty iron works. new york, march , . * * * * * for circular illustrating a new and greatly improved turbine wheel, believed to be the best and cheapest in the market, apply to pusey jones & co., wilmington, delaware * * * * * hotchkiss brick and tile machine.--send for circular to room , no. cliff street, new york. * * * * * pratt's astral oil: not the cheapest, but the best illuminating oil ever made. does not take fire or explode if the lamp be upset or broken. over , families continue to use it, and no accidents of any description, directly or indirectly, have occurred from it. oil house of charles pratt, established , new york. * * * * * union spoke works. spokes, rims, and plow handles. all goods warranted seasoned, and of the best quality. john g. davis & son, southwest cor. of leopard and otter sts., philadelphia. * * * * * [illustration] vertical & horizontal corn mills. -inch grinds bus. per hour, and -in. . price $ and $ . edward harrison, new haven, conn. * * * * * iron steamship builders. neafie & levy, penn works, marine engines, boilers, etc., philadelphia, pa. * * * * * swain turbine. "our low-water wheel from this on" will do ten per cent more work on small streams, in a dry season, than any wheel ever invented. gave the best results, in every respect, at the lowell tests. for report of tests at lowell, with diagrams and tables of power, address the swain turbine co., north chelmsford, mass. * * * * * building paper of three grades. tarred sheathing, for outside of studding, under clapboards. a non-conductor of cold, heat, and dampness. prepared plastering board, a cheap and perfect substitute for lath and plaster; makes a smooth, warm, and substantial wall, at less than half the usual cost. double thick roofing and quartz cement, make a good water and fire-proof roof, for less than $ . per square. sample and circulars sent free, by rock river paper co., chicago; or, b. e. hale, & frankfort street, n. y. * * * * * iron planers, engine lathes, drills, and other machinists' tools, of superior quality, on hand, and finishing. for sale low. for description and price address new haven manufacturing co. new haven conn. * * * * * _rumpff & lutz,_ importers and manufacturers of aniline colors and dyestuffs, colors for paperhangers and stainers. reliable recipes for dyeing and printing on silk, wool, and cotton. all new improvements in the art of dyeing, and new colors are transmitted to us by our friends in europe, as soon as they appear. beaver street, new york. * * * * * page's _patent tanned belting_ runs per cent more machinery, is nearly twice as strong, and wears per c. longer than any other. send for circular containing price lists and discounts. page brothers, sole manuf'rs, franklin, n. h. * * * * * [illustration] steam engines & boilers from to horse power including corliss engines, slide valve stationary engines, portable engines, etc. also, circular saw mills, shafting, pulleys etc. wheat and corn mills, circular saws, etc. send for price list. wood & mann steam engine company, works--utica, n. y. principal office-- cortlandt st., new york. * * * * * drills diamond pointed _steam drills._ for all kinds of rock drilling, mining, quarrying, tunneling, railroad grading, well boring, prospecting, etc. fifty to seventy-five per cent of cost and time of hand labor saved. "test cores," in form of solid cylinders of rock or mineral taken out of mines from any depth not exceeding one thousand feet, showing true value, stratification, etc. no percussion. never require sharpening. first premiums awarded in both american and europe. illustrated circulars sent on application. beware of infringements. severance & holt, proprietors and manufacturers, office wall st., new york. * * * * * _nickel plating._ beardslee nickel and manufacturing co., and fulton st., brooklyn, n. y. rights sold for the use of, and instruction given in the best method of nickel plating. an experience of twelve years enables us to offer a solution and apparatus that remain practically unchanged for years, in constant use. first premium awarded us by the american institute in . critical examination of our work solicited. all goods sent to our factory will meet with prompt attention. new york office-- dev st., room . * * * * * [illustration] best damper regulator for steam boiler. send for circulars. agents wanted. murrill & keizer, baltimore, md. * * * * * pat. solid emery wheels and oil stones, for brass and iron work, saw mills, and edge tools. northampton emery wheel co., leeds, mass. * * * * * no live mechanic can afford to be without some of baird's books for practical men. my new and enlarged catalogue of practical and scientific books, pages, vo., will be sent, free of postage, to any one who will favor me with his address. henry carey baird, industrial publisher, walnut st., philadelphia. * * * * * the fifth grand state fair of the mechanics and agricultural state association of louisiana will be held on the fair grounds of the association, in the city of new orleans, commencing saturday, april , , and continuing nine days. exhibitors are invited from every section of america. railroads, steamships, and other transportation lines, as named in the premium catalogues, will carry exhibitors and their wares to and from the fair at one half the usual rates. for further information see premium catalogue, which will be sent to any address free of charge. luther homes, secretary and treasurer, new orleans, la. * * * * * [illustration] root's safety boiler. for pamphlets with price list and testimonials, address root steam engine co,, d ave., cor. th st., n. y. the best in the market. * * * * * _wire rope._ john a. roebling's sons, manufacturers, trenton, n. j. for inclined planes, standing ship rigging, bridges, ferries, stays, or guys on derricks & cranes, tiller ropes, sash cords of copper and iron, lightning conductors of copper. special attention given to hoisting rope of all kinds for mines and elevators. apply for circular, giving price and other information. send for pamphlet on transmission of power by wire ropes. a large stock constantly on hand at new york warehouse, no. liberty street. * * * * * $ in days, made by one agent, selling silver's broom. , in use. recommended by horace greeley and _am. agriculturist_. one county for each agent. _prices reduced_. c. a. clegg & co., new york, or chicago, ill. * * * * * american saw co., manufacturers of [illustration: emerson's patent moveable toothed circular saws] and perforated circular and long saws. also solid saws of all kinds. no. ferry st., cor. gold street, new york. branch office for pacific coast, no. front street, san francisco, cal. * * * * * _machine screws,_ for all purposes, with square, round, and hexagon heads. a. w. gifford & co., worcester, mass. * * * * * patent cold rolled shafting. the fact that this shafting has per cent greater strength, a finer finish, and is truer to gage, than any other in use, renders it undoubtedly the most economical. we are also the sole manufacturers of the celebrated collins pat. coupling, and furnish pulleys, hangers, etc., of the most approved styles. price lists mailed on application to jones & laughlins, water street, pittsburgh, pa. ---> stocks of this shafting in store and for sale by fuller, dana & fitz, boston, mass. geo. place & co., chambers street, n. y. * * * * * [illustration: schlenker's patent bolt cutter new invention. address, howard iron works, buffalo, n. y. ] * * * * * _steam super-heater,_ for saving fuel, and supplying dry steam of any desired temperature. safe, durable, easily attached. h. w. bulkley engineer, liberty st., n. y. * * * * * for circular of tremper's patent variable cut-off, for high and low pressure steam engines, address pusey jones & co. wilmington delaware. * * * * * harrison safety boiler. first-class medal, world's fair, london, . and american institute fair, new york, . over , boilers in use. weston's patent differential pulley blocks. , in use. address harrison boiler works, philadelphia, pa. or, john a. coleman, agent, broadway, new york, and federal st., boston. * * * * * _doyle's_ patent differential pulley blocks, the celebrated doyle blocks have taken premiums over the differential blocks of all other makers at every fair where they have been exhibited at the same time. when you buy, see that the blocks are marked j. j. doyle. pat. jan. , . all others are infringements. samuel hall's son & co., sole manufacturers. west th street, new york. * * * * * heavy castings for forge and mill work. the m. & t. sault co. steam engine builders & founders, new haven, conn. * * * * * employment. $ a month with stencil dies. samples free. address s. m. spencer brattleboro vt. * * * * * the tanite emery wheel. does not glaze, gum, heat, or smell. address the tanite co., stroudsburg, monroe co., pa. * * * * * a. s. & j. gear & co., boston, furnish every description of wood and iron working machinery and supplies. the best in use, regardless of maker, at lowest possible rates. * * * * * _working models_ and experimental machinery, metal, or wood, made to order, by j. f. werner center st. n. y. * * * * * mcnab & harlan, manufacturers of wrought iron pipe and fittings, brass cocks, valves, gage cocks, whistles, water gages, and oil cups, harlin's patent lubricator, plumber's brass work, getty's patent pipe cutter, getty's patent proving pump and gage. no. john st., new york. * * * * * the allen engine works, the allen engine. fourth avenue and th and st sts., new york city manufacturers of porter's governor, the allen boiler, and standard straight edges, surface plates, and angle plates. four first premiums were awarded to us at the fair of the american institute, . send for our illustrated circular. * * * * * _l. w. pond--new tools._ extra heavy and improved patterns. lathes, planers, drills, of all sizes; vertical boring mills, ten feet swing, and under; milling machines, gear and bolt cutters; hand punches and shears for iron. office and warerooms, liberty st., new york; works at worcester, mass. a. c. stebbins, new york, agent. * * * * * water-proof _building paper_ (no tar), for roofing, sheathing, ceilings, oil-cloths, shoe stiffenings, tags, trunks, cartridges, blasting, pass-book covers, grain and flour bins, etc., for sale by j. hunter, jr., paper warehouse, duane st., new york. * * * * * scientific american for . twenty-sixth year. every number is printed on fine paper, and elegantly illustrated with original engravings representing new inventions, novelties in mechanics, manufactures, chemistry, photography, architecture. agriculture. engineering, science, and art. farmers, mechanics, inventors, engineers, chemists manufacturers and people of all professions or trades will find the scientific american of great value and interest. the editors are assisted by many of the ablest american and european writers, and having access to all the leading scientific and mechanical journals of the world, the columns of the scientific american are constantly enriched with the choicest information. an official list of all the patents issued is published weekly. the yearly numbers of the scientific american make two splendid volumes of nearly one thousand pages equivalent in size to four thousand ordinary book pages. specimen copies sent free. terms--$ . a year, $ . half year; clubs of ten copies for one year, at $ . each, $ . , with a splendid premium to the person who forms the club, consisting of a copy of the celebrated steel plate engraving, "men of progress." address munn & co., publishers of the scientific american. park row, new york. * * * * * the "scientific american" is printed with chas. eneu johnson & co.'s ink. tenth and lombard sts. philadelphia, and gold st. new york. transcriber's note the punctuation and spelling from the original text have been faithfully preserved. only obvious typographical errors have been corrected. subscripts are represented as x_ . superscripts are represented by x^ . how it works author's note. i beg to thank the following gentlemen and firms for the help they have given me in connection with the letterpress and illustrations of "how it works"-- messrs. f.j.c. pole and m.g. tweedie (for revision of ms.); w. lineham; j.f. kendall; e. edser; a.d. helps; j. limb; the edison bell phonograph co.; messrs. holmes and co.; the pelton wheel co.; messrs. babcock and wilcox; messrs. siebe, gorman, and co.; messrs. negretti and zambra; messrs. chubb; the yale lock co.; the micrometer engineering co.; messrs. marshall and sons; the maignen filter co.; messrs. broadwood and co. [illustration: on the footplate of a locomotive.] how it works dealing in simple language with steam, electricity, light, heat, sound, hydraulics, optics, etc. and with their applications to apparatus in common use by archibald williams author of "the romance of modern invention," "the romance of mining," etc., etc. thomas nelson and sons london, edinburgh, dublin, and new york preface. how does it work? this question has been put to me so often by persons young and old that i have at last decided to answer it in such a manner that a much larger public than that with which i have personal acquaintance may be able to satisfy themselves as to the principles underlying many of the mechanisms met with in everyday life. in order to include steam, electricity, optics, hydraulics, thermics, light, and a variety of detached mechanisms which cannot be classified under any one of these heads, within the compass of about pages, i have to be content with a comparatively brief treatment of each subject. this brevity has in turn compelled me to deal with principles rather than with detailed descriptions of individual devices--though in several cases recognized types are examined. the reader will look in vain for accounts of the yerkes telescope, of the latest thing in motor cars, and of the largest locomotive. but he will be put in the way of understanding the essential nature of _all_ telescopes, motors, and steam-engines so far as they are at present developed, which i think may be of greater ultimate profit to the uninitiated. while careful to avoid puzzling the reader by the use of mysterious phraseology i consider that the parts of a machine should be given their technical names wherever possible. to prevent misconception, many of the diagrams accompanying the letterpress have words as well as letters written on them. this course also obviates the wearisome reference from text to diagram necessitated by the use of solitary letters or figures. i may add, with regard to the diagrams of this book, that they are purposely somewhat unconventional, not being drawn to scale nor conforming to the canons of professional draughtsmanship. where advisable, a part of a machine has been exaggerated to show its details. as a rule solid black has been preferred to fine shading in sectional drawings, and all unnecessary lines are omitted. i would here acknowledge my indebtedness to my draughtsman, mr. frank hodgson, for his care and industry in preparing the two hundred or more diagrams for which he was responsible. four organs of the body--the eye, the ear, the larynx, and the heart--are noticed in appropriate places. the eye is compared with the camera, the larynx with a reed pipe, the heart with a pump, while the ear fitly opens the chapter on acoustics. the reader who is unacquainted with physiology will thus be enabled to appreciate the better these marvellous devices, far more marvellous, by reason of their absolutely automatic action, than any creation of human hands. a.w. uplands, stoke poges, bucks. contents. chapter i.--the steam-engine. what is steam?--the mechanical energy of steam--the boiler--the circulation of water in a boiler--the enclosed furnace--the multitubular boiler--fire-tube boilers--other types of boilers--aids to combustion--boiler fittings--the safety-valve--the water-gauge--the steam-gauge--the water supply to a boiler chapter ii.--the conversion of heat energy into mechanical motion. reciprocating engines--double-cylinder engines--the function of the fly-wheel--the cylinder--the slide-valve--the eccentric--"lap" of the valve: expansion of steam--how the cut-off is managed--limit of expansive working--compound engines--arrangement of expansion engines--compound locomotives--reversing gears--"linking-up"--piston-valves--speed governors--marine-speed governors--the condenser chapter iii.--the steam turbine. how a turbine works--the de laval turbine--the parsons turbine--description of the parsons turbine--the expansive action of steam in a parsons turbine--balancing the thrust--advantages of the marine turbine chapter iv.--the internal-combustion engine. the meaning of the term--action of the internal-combustion engine--the motor car--the starting-handle--the engine--the carburetter--ignition of the charge--advancing the spark--governing the engine--the clutch--the gear-box--the compensating gear--the silencer--the brakes--speed of cars chapter v.--electrical apparatus. what is electricity?--forms of electricity--magnetism--the permanent magnet--lines of force--electro-magnets--the electric bell--the induction coil--the condenser--transformation of current--uses of the induction coil chapter vi.--the electric telegraph. needle instruments--influence of current on the magnetic needle--method of reversing the current--sounding instruments--telegraphic relays--recording telegraphs--high-speed telegraphy chapter vii.--wireless telegraphy. the transmitting apparatus--the receiving apparatus--syntonic transmission--the advance of wireless telegraphy chapter viii.--the telephone. the bell telephone--the edison transmitter--the granular carbon transmitter--general arrangement of a telephone circuit--double-line circuits--telephone exchanges--submarine telephony chapter ix.--dynamos and electric motors. a simple dynamo--continuous-current dynamos--multipolar dynamos--exciting the field magnets--alternating current dynamos--the transmission of power--the electric motor--electric lighting--the incandescent lamp--arc lamps--"series" and "parallel" arrangement of lamps--current for electric lamps--electroplating chapter x.--railway brakes. the vacuum automatic brake--the westinghouse air-brake chapter xi.--railway signalling. the block system--position of signals--interlocking the signals--locking gear--points--points and signals in combination--working the block system--series of signalling operations--single line signals--the train staff--train staff and ticket--electric train staff system--interlocking--signalling operations--power signalling--pneumatic signalling--automatic signalling chapter xii.--optics. lenses--the image cast by a convex lens--focus--relative position of object and lens--correction of lenses for colour--spherical aberration--distortion of image--the human eye--the use of spectacles--the blind spot chapter xiii.--the microscope, the telescope, and the magic-lantern. the simple microscope--use of the simple microscope in the telescope--the terrestrial telescope--the galilean telescope--the prismatic telescope--the reflecting telescope--the parabolic mirror--the compound microscope--the magic-lantern--the bioscope--the plane mirror chapter xiv.--sound and musical instruments. nature of sound--the ear--musical instruments--the vibration of strings--the sounding-board and the frame of a piano--the strings--the striking mechanism--the quality of a note chapter xv.--wind instruments. longitudinal vibration--columns of air--resonance of columns of air--length and tone--the open pipe--the overtones of an open pipe--where overtones are used--the arrangement of the pipes and pedals--separate sound-boards--varieties of stops--tuning pipes and reeds--the bellows--electric and pneumatic actions--the largest organ in the world--human reeds chapter xvi.--talking-machines. the phonograph--the recorder--the reproducer--the gramophone--the making of records--cylinder records--gramophone records chapter xvii.--why the wind blows. why the wind blows--land and sea breezes--light air and moisture--the barometer--the column barometer--the wheel barometer--a very simple barometer--the aneroid barometer--barometers and weather--the diving-bell--the diving-dress--air-pumps--pneumatic tyres--the air-gun--the self-closing door-stop--the action of wind on oblique surfaces--the balloon--the flying-machine chapter xviii.--hydraulic machinery. the siphon--the bucket pump--the force-pump--the most marvellous pump--the blood channels--the course of the blood--the hydraulic press--household water-supply fittings--the ball-cock--the water-meter--water-supply systems--the household filter--gas traps--water engines--the cream separator--the "hydro" chapter xix.--heating and lighting. the hot-water supply--the tank system--the cylinder system--how a lamp works--gas and gasworks--automatic stoking--a gas governor--the gas meter--incandescent gas lighting chapter xx.--various mechanisms. clocks and watches:--a short history of timepieces--the construction of timepieces--the driving power--the escapement--compensating pendulums--the spring balance--the cylinder escapement--the lever escapement--compensated balance-wheels--keyless winding mechanism for watches--the hour hand train. locks:--the chubb lock--the yale lock. the cycle:--the gearing of a cycle--the free wheel--the change-speed gear. agricultural machines:--the threshing-machine--mowing-machines. some natural phenomena:--why sun-heat varies in intensity--the tides--why high tide varies daily how it works. chapter i. the steam-engine. what is steam?--the mechanical energy of steam--the boiler--the circulation of water in a boiler--the enclosed furnace--the multitubular boiler--fire-tube boilers--other types of boilers--aids to combustion--boiler fittings--the safety-valve--the water-gauge--the steam-gauge--the water supply to a boiler. what is steam? if ice be heated above ° fahrenheit, its molecules lose their cohesion, and move freely round one another--the ice is turned into water. heat water above ° fahrenheit, and the molecules exhibit a violent mutual repulsion, and, like dormant bees revived by spring sunshine, separate and dart to and fro. if confined in an air-tight vessel, the molecules have their flights curtailed, and beat more and more violently against their prison walls, so that every square inch of the vessel is subjected to a rising pressure. we may compare the action of the steam molecules to that of bullets fired from a machine-gun at a plate mounted on a spring. the faster the bullets came, the greater would be the continuous compression of the spring. the mechanical energy of steam. if steam is let into one end of a cylinder behind an air-tight but freely-moving piston, it will bombard the walls of the cylinder and the piston; and if the united push of the molecules on the one side of the latter is greater than the resistance on the other side opposing its motion, the piston must move. having thus partly got their liberty, the molecules become less active, and do not rush about so vigorously. the pressure on the piston decreases as it moves. but if the piston were driven back to its original position against the force of the steam, the molecular activity--that is, pressure--would be restored. we are here assuming that no heat has passed through the cylinder or piston and been radiated into the air; for any loss of heat means loss of energy, since heat _is_ energy. the boiler. the combustion of fuel in a furnace causes the walls of the furnace to become _hot_, which means that the molecules of the substance forming the walls are thrown into violent agitation. if the walls are what are called "good conductors" of heat, they will transmit the agitation through them to any surrounding substance. in the case of the ordinary house stove this is the air, which itself is agitated, or grows warm. a steam-boiler has the furnace walls surrounded by water, and its function is to transmit molecular movement (heat, or energy) through the furnace plates to the water until the point is reached when steam generates. at atmospheric pressure--that is, if not confined in any way--steam would fill , times the space which its molecules occupied in their watery formation. if we seal up the boiler so that no escape is possible for the steam molecules, their motion becomes more and more rapid, and _pressure_ is developed by their beating on the walls of the boiler. there is theoretically no limit to which the pressure may be raised, provided that sufficient fuel-combustion energy is transmitted to the vaporizing water. to raise steam in large quantities we must employ a fuel which develops great heat in proportion to its weight, is readily procured, and cheap. coal fulfils all these conditions. of the million tons mined annually throughout the world, million tons are burnt in the furnaces of steam-boilers. a good boiler must be--( ) strong enough to withstand much higher pressures than that at which it is worked; ( ) so designed as to burn its fuel to the greatest advantage. even in the best-designed boilers a large part of the combustion heat passes through the chimney, while a further proportion is radiated from the boiler. professor john perry[ ] considers that this waste amounts, under the best conditions at present obtainable, to eleven-twelfths of the whole. we have to burn a shillingsworth of coal to capture the energy stored in a pennyworth. yet the steam-engine of to-day is three or four times as efficient as the engine of fifty years ago. this is due to radical improvements in the design of boilers and of the machinery which converts the heat energy of steam into mechanical motion. circulation of water in a boiler. if you place a pot filled with water on an open fire, and watch it when it boils, you will notice that the water heaves up at the sides and plunges down at the centre. this is due to the water being heated most at the sides, and therefore being lightest there. the rising steam-bubbles also carry it up. on reaching the surface, the bubbles burst, the steam escapes, and the water loses some of its heat, and rushes down again to take the place of steam-laden water rising. [illustration: fig. .] [illustration: fig. .] if the fire is very fierce, steam-bubbles may rise from all points at the bottom, and impede downward currents (fig. ). the pot then "boils over." fig. shows a method of preventing this trouble. we lower into our pot a vessel of somewhat smaller diameter, with a hole in the bottom, arranged in such a manner as to leave a space between it and the pot all round. the upward currents are then separated entirely from the downward, and the fire can be forced to a very much greater extent than before without the water boiling over. this very simple arrangement is the basis of many devices for producing free circulation of the water in steam-boilers. we can easily follow out the process of development. in fig. we see a simple u-tube depending from a vessel of water. heat is applied to the left leg, and a steady circulation at once commences. in order to increase the heating surface we can extend the heated leg into a long incline (fig. ), beneath which three lamps instead of only one are placed. the direction of the circulation is the same, but its rate is increased. [illustration: fig. .] a further improvement results from increasing the number of tubes (fig. ), keeping them all on the slant, so that the heated water and steam may rise freely. the enclosed furnace. [illustration: fig. .] [illustration: fig. .] still, a lot of the heat gets away. in a steam-boiler the burning fuel is enclosed either by fire-brick or a "water-jacket," forming part of the boiler. a water-jacket signifies a double coating of metal plates with a space between, which is filled with water (see fig. ). the fire is now enclosed much as it is in a kitchen range. but our boiler must not be so wasteful of the heat as is that useful household fixture. on their way to the funnel the flames and hot gases should act on a very large metal or other surface in contact with the water of the boiler, in order to give up a due proportion of their heat. [illustration: fig. .--diagrammatic sketch of a locomotive type of boiler. water indicated by dotted lines. the arrows show the direction taken by the air and hot gases from the air-door to the funnel.] the multitubular boiler. [illustration: fig. .--the babcock and wilcox water-tube boiler. one side of the brick seating has been removed to show the arrangement of the water-tubes and furnace.] to save room, boilers which have to make steam very quickly and at high pressures are largely composed of pipes. such boilers we call multitubular. they are of two kinds--( ) _water_-tube boilers; in which the water circulates through tubes exposed to the furnace heat. the babcock and wilcox boiler (fig. ) is typical of this variety. ( ) _fire_-tube boilers; in which the hot gases pass through tubes surrounded by water. the ordinary locomotive boiler (fig. ) illustrates this form. the babcock and wilcox boiler is widely used in mines, power stations, and, in a modified form, on shipboard. it consists of two main parts--( ) a drum, h, in the upper part of which the steam collects; ( ) a group of pipes arranged on the principle illustrated by fig. . the boiler is seated on a rectangular frame of fire-bricks. at one end is the furnace door; at the other the exit to the chimney. from the furnace f the flames and hot gases rise round the upper end of the sloping tubes tt into the space a, where they play upon the under surface of h before plunging downward again among the tubes into the space b. here the temperature is lower. the arrows indicate further journeys upwards into the space c on the right of a fire-brick division, and past the down tubes ss into d, whence the hot gases find an escape into the chimney through the opening e. it will be noticed that the greatest heat is brought to bear on tt near their junction with uu, the "uptake" tubes; and that every succeeding passage of the pipes brings the gradually cooling gases nearer to the "downtake" tubes ss. the pipes tt are easily brushed and scraped after the removal of plugs from the "headers" into which the tube ends are expanded. other well-known water-tube boilers are the yarrow, belleville, stirling, and thorneycroft, all used for driving marine engines. fire-tube boilers. fig. shows a locomotive boiler in section. to the right is the fire-box, surrounded on all sides by a water-jacket in direct communication with the barrel of the boiler. the inner shell of the fire-box is often made of copper, which withstands the fierce heat better than steel; the outer, like the rest of the boiler, is of steel plates from / to / inch thick. the shells of the jacket are braced together by a large number of rivets, rr; and the top, or crown, is strengthened by heavy longitudinal girders riveted to it, or is braced to the top of the boiler by long bolts. a large number of fire-tubes (only three are shown in the diagram for the sake of simplicity) extend from the fire-box to the smoke-box. the most powerful "mammoth" american locomotives have or more tubes, which, with the fire-box, give , square feet of surface for the furnace heat to act upon. these tubes are expanded at their ends by a special tool into the tube-plates of the fire-box and boiler front. george stephenson and his predecessors experienced great difficulty in rendering the tube-end joints quite water-tight, but the invention of the "expander" has removed this trouble. the _fire-brick arch_ shown (fig. ) in the fire-box is used to deflect the flames towards the back of the fire-box, so that the hot gases may be retarded somewhat, and their combustion rendered more perfect. it also helps to distribute the heat more evenly over the whole of the inside of the box, and prevents cold air from flying directly from the firing door to the tubes. in some american and continental locomotives the fire-brick arch is replaced by a "water bridge," which serves the same purpose, while giving additional heating surface. the water circulation in a locomotive boiler is--upwards at the fire-box end, where the heat is most intense; forward along the surface; downwards at the smoke-box end; backwards along the bottom of the barrel. other types of boilers. for small stationary land engines the _vertical_ boiler is much used. in fig. we have three forms of this type--a and b with cross water-tubes; c with vertical fire-tubes. the furnace in every case is surrounded by water, and fed through a door at one side. [illustration: fig. .--diagrammatic representation of three types of vertical boilers.] the _lancashire_ boiler is of large size. it has a cylindrical shell, measuring up to feet in length and feet in diameter, traversed from end to end by two large flues, in the rear part of which are situated the furnaces. the boiler is fixed on a seating of fire-bricks, so built up as to form three flues, a and bb, shown in cross section in fig. . the furnace gases, after leaving the two furnace flues, are deflected downwards into the channel a, by which they pass underneath the boiler to a point almost under the furnace, where they divide right and left and travel through cross passages into the side channels bb, to be led along the boiler's flanks to the chimney exit c. by this arrangement the effective heating surface is greatly increased; and the passages being large, natural draught generally suffices to maintain proper combustion. the lancashire boiler is much used in factories and (in a modified form) on ships, since it is a steady steamer and is easily kept in order. [illustration: fig. .--cross and longitudinal sections of a lancashire boiler.] in marine boilers of cylindrical shape cross water-tubes and fire-tubes are often employed to increase the heating surface. return tubes are also led through the water to the funnels, situated at the same end as the furnace. aids to combustion. we may now turn our attention more particularly to the chemical process called _combustion_, upon which a boiler depends for its heat. ordinary steam coal contains about per cent. of carbon, per cent. of oxygen, and per cent. of hydrogen, besides traces of nitrogen and sulphur and a small incombustible residue. when the coal burns, the nitrogen is released and passes away without combining with any of the other elements. the sulphur unites with hydrogen and forms sulphuretted hydrogen (also named sulphurous acid), which is injurious to steel plates, and is largely responsible for the decay of tubes and funnels. more of the hydrogen unites with the oxygen as steam. the most important element in coal is the carbon (known chemically by the symbol c). its combination with oxygen, called combustion, is the act which heats the boiler. only when the carbon present has combined with the greatest possible amount of oxygen that it will take into partnership is the combustion complete and the full heat-value (fixed by scientific experiment at , thermal units per pound of carbon) developed. now, carbon may unite with oxygen, atom for atom, and form _carbon monoxide_ (co); or in the proportion of one atom of carbon to _two_ of oxygen, and form _carbon dioxide_ (co_ ). the former gas is combustible--that is, will admit another atom of carbon to the molecule--but the latter is saturated with oxygen, and will not burn, or, to put it otherwise, is the product of _perfect_ combustion. a properly designed furnace, supplied with a due amount of air, will cause nearly all the carbon in the coal burnt to combine with the full amount of oxygen. on the other hand, if the oxygen supply is inefficient, co as well as co_ will form, and there will be a heat loss, equal in extreme cases to two-thirds of the whole. it is therefore necessary that a furnace which has to eat up fuel at a great pace should be artificially fed with air in the proportion of from to _pounds_ of air for every pound of fuel. there are two methods of creating a violent draught through the furnace. the first is-- the _forced draught_; very simply exemplified by the ordinary bellows used in every house. on a ship (fig. ) the principle is developed as follows:--the boilers are situated in a compartment or compartments having no communication with the outer air, except for the passages down which air is forced by powerful fans at a pressure considerably greater than that of the atmosphere. there is only one "way out"--namely, through the furnace and tubes (or gas-ways) of the boiler, and the funnel. so through these it rushes, raising the fuel to white heat. as may easily be imagined, the temperature of a stokehold, especially in the tropics, is far from pleasant. in the red sea the thermometer sometimes rises to ° fahrenheit or more, and the poor stokers have a very bad time of it. [illustration: fig. .--sketch showing how the "forced draught" is produced in a stokehold and how it affects the furnaces.] [illustration: scene in the stokehold of a battle-ship.] the second system is that of the _induced draught_. here air is _sucked_ through the furnace by creating a vacuum in the funnel and in a chamber opening into it. turning to fig. , we see a pipe through which the exhaust steam from the locomotive's cylinders is shot upwards into the funnel, in which, and in the smoke-box beneath it, a strong vacuum is formed while the engine is running. now, "nature abhors a vacuum," so air will get into the smoke-box if there be a way open. there is--through the air-doors at the bottom of the furnace, the furnace itself, and the fire-tubes; and on the way oxygen combines with the carbon of the fuel, to form carbon dioxide. the power of the draught is so great that, as one often notices when a train passes during the night, red-hot cinders, plucked from the fire-box, and dragged through the tubes, are hurled far into the air. it might be mentioned in parenthesis that the so-called "smoke" which pours from the funnel of a moving engine is mainly condensing steam. a steamship, on the other hand, belches smoke only from its funnels, as fresh water is far too precious to waste as steam. we shall refer to this later on (p. ). boiler fittings. the most important fittings on a boiler are:--( ) the safety-valve; ( ) the water-gauge; ( ) the steam-gauge; ( ) the mechanisms for feeding it with water. the safety-valve. professor thurston, an eminent authority on the steam-engine, has estimated that a plain cylindrical boiler carrying lbs. pressure to the square inch contains sufficient stored energy to project it into the air a vertical distance of - / miles. in the case of a lancashire boiler at equal pressure the distance would be - / miles; of a locomotive boiler, at lbs., - / miles; of a steam tubular boiler, at lbs., mile. according to the same writer, a cubic foot of heated water under a pressure of from to lbs. per square inch has _about the same energy as one pound of gunpowder_. steam is a good servant, but a terrible master. it must be kept under strict control. however strong a boiler may be, it will burst if the steam pressure in it be raised to a certain point; and some device must therefore be fitted on it which will give the steam free egress before that point is reached. a device of this kind is called a _safety-valve_. it usually blows off at less than half the greatest pressure that the boiler has been proved by experiment to be capable of withstanding. in principle the safety-valve denotes an orifice closed by an accurately-fitting plug, which is pressed against its seat on the boiler top by a weighted lever, or by a spring. as soon as the steam pressure on the face of the plug exceeds the counteracting force of the weight or spring, the plug rises, and steam escapes until equilibrium of the opposing forces is restored. on stationary engines a lever safety-valve is commonly employed (fig. ). the blowing-off point can be varied by shifting the weight along the arm so as to give it a greater or less leverage. on locomotive and marine boilers, where shocks and movements have to be reckoned with, weights are replaced by springs, set to a certain tension, and locked up so that they cannot be tampered with. [illustration: fig. .--a lever safety-valve. v, valve; s, seating; p, pin; l, lever; f, fulcrum; w, weight. the figures indicate the positions at which the weight should be placed for the valve to act when the pressure rises to that number of pounds per square inch.] boilers are tested by filling the boilers quite full and ( ) by heating the water, which expands slightly, but with great pressure; ( ) by forcing in additional water with a powerful pump. in either case a rupture would not be attended by an explosion, as water is very inelastic. the days when an engineer could "sit on the valves"--that is, screw them down--to obtain greater pressure, are now past, and with them a considerable proportion of the dangers of high-pressure steam. the factory act of , in force throughout the british isles, provides that every boiler for generating steam in a factory or workshop where the act applies must have a proper safety-valve, steam-gauge, and water-gauge; and that boilers and fittings must be examined by a competent person at least once in every fourteen months. neglect of these provisions renders the owner of a boiler liable to heavy penalties if an explosion occurs. one of the most disastrous explosions on record took place at the redcar iron works, yorkshire, in june . in this case, twelve out of fifteen boilers ranged side by side burst, through one proving too weak for its work. the flying fragments of this boiler, striking the sides of other boilers, exploded them, and so the damage was transmitted down the line. twenty men were killed and injured; while masses of metal, weighing several tons each, were hurled yards, and caused widespread damage. the following is taken from a journal, dated december , : "_providence_ (_rhode island_).--a recent prophecy that a boiler would explode between december and in a store has seriously affected the christmas trade. shoppers are incredibly nervous. one store advertises, 'no boilers are being used; lifts running electrically.' all stores have had their boilers inspected." the water-gauge. no fitting of a boiler is more important than the _water-gauge_, which shows the level at which the water stands. the engineer must continually consult his gauge, for if the water gets too low, pipes and other surfaces exposed to the furnace flames may burn through, with disastrous results; while, on the other hand, too much water will cause bad steaming. a section of an ordinary gauge is seen in fig. . it consists of two parts, each furnished with a gland, g, to make a steam-tight joint round the glass tube, which is inserted through the hole covered by the plug p^ . the cocks t^ t^ are normally open, allowing the ingress of steam and water respectively to the tube. cock t^ is kept closed unless for any reason it is necessary to blow steam or water through the gauge. the holes c c can be cleaned out if the plugs p^ p^ are removed. most gauges on high-pressure boilers have a thick glass screen in front, so that in the event of the tube breaking, the steam and water may not blow directly on to the attendants. a further precaution is to include two ball-valves near the ends of the gauge-glass. under ordinary conditions the balls lie in depressions clear of the ways; but when a rush of steam or water occurs they are sucked into their seatings and block all egress. [illustration: fig. .--section of a water-gauge.] on many boilers two water-gauges are fitted, since any gauge may work badly at times. the glasses are tested to a pressure of , lbs. or more to the square inch before use. the steam-gauge. it is of the utmost importance that a person in charge of a boiler should know what pressure the steam has reached. every boiler is therefore fitted with one _steam-gauge_; many with two, lest one might be unreliable. there are two principal types of steam-gauge:--( ) the bourdon; ( ) the schäffer-budenberg. the principle of the bourdon is illustrated by fig. , in which a is a piece of rubber tubing closed at one end, and at the other drawn over the nozzle of a cycle tyre inflator. if bent in a curve, as shown, the section of the tube is an oval. when air is pumped in, the rubber walls endeavour to assume a circular section, because this shape encloses a larger area than an oval of equal circumference, and therefore makes room for a larger volume of air. in doing so the tube straightens itself, and assumes the position indicated by the dotted lines. hang an empty "inner tube" of a pneumatic tyre over a nail and inflate it, and you will get a good illustration of the principle. [illustration: fig. .--showing the principle of the steam-gauge.] [illustration: fig. .--bourdon steam-gauge. part of dial removed to show mechanism.] in fig. we have a bourdon gauge, with part of the dial face broken away to show the internal mechanism. t is a flattened metal tube soldered at one end into a hollow casting, into which screws a tap connected with the boiler. the other end (closed) is attached to a link, l, which works an arm of a quadrant rack, r, engaging with a small pinion, p, actuating the pointer. as the steam pressure rises, the tube t moves its free end outwards towards the position shown by the dotted lines, and traverses the arm of the rack, so shifting the pointer round the scale. as the pressure falls, the tube gradually returns to its zero position. the schäffer-budenberg gauge depends for its action on the elasticity of a thin corrugated metal plate, on one side of which steam presses. as the plate bulges upwards it pushes up a small rod resting on it, which operates a quadrant and rack similar to that of the bourdon gauge. the principle is employed in another form for the aneroid barometer (p. ). the water supply to a boiler. the water inside a boiler is kept at a proper level by ( ) pumps or ( ) injectors. the former are most commonly used on stationary and marine boilers. as their mechanism is much the same as that of ordinary force pumps, which will be described in a later chapter, we may pass at once to the _injector_, now almost universally used on locomotive, and sometimes on stationary boilers. at first sight the injector is a mechanical paradox, since it employs the steam from a boiler to blow water into the boiler. in fig. we have an illustration of the principle of an injector. steam is led from the boiler through pipe a, which terminates in a nozzle surrounded by a cone, e, connected by the pipe b with the water tank. when steam is turned on it rushes with immense velocity from the nozzle, and creates a partial vacuum in cone e, which soon fills with water. on meeting the water the steam condenses, but not before it has imparted some of its _velocity_ to the water, which thus gains sufficient momentum to force down the valve and find its way to the boiler. the overflow space o o between e and c allows steam and water to escape until the water has gathered the requisite momentum. [illustration: fig. .--diagram illustrating the principle of a steam-injector.] [illustration: fig. .--the giffard injector.] a form of injector very commonly used is giffard's (fig. ). steam is allowed to enter by screwing up the valve v. as it rushes through the nozzle of the cone a it takes up water and projects it into the "mixing cone" b, which can be raised or lowered by the pinion d (worked by the hand-wheel wheel shown) so as to regulate the amount of water admitted to b. at the centre of b is an aperture, o, communicating with the overflow. the water passes to the boiler through the valve on the left. it will be noticed that the cone a and the part of b above the orifice o contract downward. this is to convert the _pressure_ of the steam into _velocity_. below o is a cone, the diameter of which increases downwards. here the _velocity_ of the water is converted back into _pressure_ in obedience to a well-known hydromechanic law. an injector does not work well if the feed-water be too hot to condense the steam quickly; and it may be taken as a rule that the warmer the water, the smaller is the amount of it injected by a given weight of steam.[ ] some injectors have flap-valves covering the overflow orifice, to prevent air being sucked in and carried to the boiler. when an injector receives a sudden shock, such as that produced by the passing of a locomotive over points, it is liable to "fly off"--that is, stop momentarily--and then send the steam and water through the overflow. if this happens, both steam and water must be turned off, and the injector be restarted; unless it be of the _self-starting_ variety, which automatically controls the admission of water to the "mixing-cone," and allows the injector to "pick up" of itself. for economy's sake part of the steam expelled from the cylinders of a locomotive is sometimes used to work an injector, which passes the water on, at a pressure of lbs. to the square inch, to a second injector operated by high-pressure steam coming direct from the boiler, which increases its velocity sufficiently to overcome the boiler pressure. in this case only a fraction of the weight of high-pressure steam is required to inject a given weight of water, as compared with that used in a single-stage injector. [ ] "the steam-engine," p. . [ ] by "weight of steam" is meant the steam produced by boiling a certain weight of water. a pound of steam, if condensed, would form a pound of water. chapter ii. the conversion of heat energy into mechanical motion. reciprocating engines--double-cylinder engines--the function of the fly-wheel--the cylinder--the slide-valve--the eccentric--"lap" of the valve: expansion of steam--how the cut-off is managed--limit of expansive working--compound engines--arrangement of expansion engines--compound locomotives--reversing gears--"linking-up"--piston-valves--speed governors--marine-speed governors--the condenser. having treated at some length the apparatus used for converting water into high-pressure steam, we may pass at once to a consideration of the mechanisms which convert the energy of steam into mechanical motion, or _work_. steam-engines are of two kinds:--( ) _reciprocating_, employing cylinders and cranks; ( ) _rotary_, called turbines. reciprocating engines. [illustration: fig. .--sketch showing parts of a horizontal steam-engine.] fig. is a skeleton diagram of the simplest form of reciprocating engine. c is a _cylinder_ to which steam is admitted through the _steam-ways_[ ] w w, first on one side of the piston p, then on the other. the pressure on the piston pushes it along the cylinder, and the force is transmitted through the piston rod p r to the _connecting rod_ c r, which causes the _crank_ k to revolve. at the point where the two rods meet there is a "crosshead," h, running to and fro in a guide to prevent the piston rod being broken or bent by the oblique thrusts and pulls which it imparts through c r to the crank k. the latter is keyed to a _shaft_ s carrying the fly-wheel, or, in the case of a locomotive, the driving-wheels. the crank shaft revolves in bearings. the internal diameter of a cylinder is called its _bore_. the travel of the piston is called its _stroke_. the distance from the centre of the shaft to the centre of the crank pin is called the crank's _throw_, which is half of the piston's _stroke_. an engine of this type is called double-acting, as the piston is pushed alternately backwards and forwards by the steam. when piston rod, connecting rod, and crank lie in a straight line--that is, when the piston is fully out, or fully in--the crank is said to be at a "dead point;" for, were the crank turned to such a position, the admission of steam would not produce motion, since the thrust or pull would be entirely absorbed by the bearings. [illustration: fig. .--sectional plan of a horizontal engine.] double-cylinder engines. [illustration: fig. .] [illustration: fig. .] locomotive, marine, and all other engines which must be started in any position have at least _two_ cylinders, and as many cranks set at an angle to one another. fig. demonstrates that when one crank, c_ , of a double-cylinder engine is at a "dead point," the other, c_ , has reached a position at which the piston exerts the maximum of turning power. in fig. each crank is at ° with the horizontal, and both pistons are able to do work. the power of one piston is constantly increasing while that of the other is decreasing. if _single_-action cylinders are used, at least _three_ of these are needed to produce a perpetual turning movement, independently of a fly-wheel. the function of the fly-wheel. a fly-wheel acts as a _reservoir of energy_, to carry the crank of a single-cylinder engine past the "dead points." it is useful in all reciprocating engines to produce steady running, as a heavy wheel acts as a drag on the effects of a sudden increase or decrease of steam pressure. in a pump, mangold-slicer, cake-crusher, or chaff-cutter, the fly-wheel helps the operator to pass _his_ dead points--that is, those parts of the circle described by the handle in which he can do little work. the cylinder. [illustration: fig. .--diagrammatic section of a cylinder and its slide-valve.] the cylinders of an engine take the place of the muscular system of the human body. in fig. we have a cylinder and its slide-valve shown in section. first of all, look at p, the piston. round it are white grooves, r r, in which rings are fitted to prevent the passage of steam past the piston. the rings are cut through at one point in their circumference, and slightly opened, so that when in position they press all round against the walls of the cylinder. after a little use they "settle down to their work"--that is, wear to a true fit in the cylinder. each end of the cylinder is closed by a cover, one of which has a boss cast on it, pierced by a hole for the piston rod to work through. to prevent the escape of steam the boss is hollowed out true to accommodate a _gland_, g^ , which is threaded on the rod and screwed up against the boss; the internal space between them being filled with packing. steam from the boiler enters the steam-chest, and would have access to both sides of the piston simultaneously through the steam-ways, w w, were it not for the slide-valve, a hollow box open at the bottom, and long enough for its edges to cover both steam-ways at once. between w w is e, the passage for the exhaust steam to escape by. the edges of the slide-valve are perfectly flat, as is the face over which the valve moves, so that no steam may pass under the edges. in our illustration the piston has just begun to move towards the right. steam enters by the left steam-way, which the valve is just commencing to uncover. as the piston moves, the valve moves in the same direction until the port is fully uncovered, when it begins to move back again; and just before the piston has finished its stroke the steam-way on the right begins to open. the steam-way on the left is now in communication with the exhaust port e, so that the steam that has done its duty is released and pressed from the cylinder by the piston. _reciprocation_ is this backward and forward motion of the piston: hence the term "reciprocating" engines. the linear motion of the piston rod is converted into rotatory motion by the connecting rod and crank. [illustration: fig. .--perspective section of cylinder.] the use of a crank appears to be so obvious a method of producing this conversion that it is interesting to learn that, when james watt produced his "rotative engine" in he was unable to use the crank because it had already been patented by one matthew wasborough. watt was not easily daunted, however, and within a twelvemonth had himself patented five other devices for obtaining rotatory motion from a piston rod. before passing on, it may be mentioned that watt was the father of the modern--that is, the high-pressure--steam-engine; and that, owing to the imperfection of the existing machinery, the difficulties he had to overcome were enormous. on one occasion he congratulated himself because one of his steam-cylinders was only three-eighths of an inch out of truth in the bore. nowadays a good firm would reject a cylinder / of an inch out of truth; and in small petrol-engines / of an inch is sometimes the greatest "limit of error" allowed. [illustration: fig. .--the eccentric and its rod.] the eccentric is used to move the slide-valve to and fro over the steam ports (fig. ). it consists of three main parts--the _sheave_, or circular plate s, mounted on the crank shaft; and the two _straps_ which encircle it, and in which it revolves. to one strap is bolted the "big end" of the eccentric rod, which engages at its other end with the valve rod. the straps are semicircular and held together by strong bolts, b b, passing through lugs, or thickenings at the ends of the semicircles. the sheave has a deep groove all round the edges, in which the straps ride. the "eccentricity" or "throw" of an eccentric is the distance between c^ , the centre of the shaft, and c^ , the centre of the sheave. the throw must equal half of the distance which the slide-valve has to travel over the steam ports. a tapering steel wedge or key, k, sunk half in the eccentric and half in a slot in the shaft, holds the eccentric steady and prevents it slipping. some eccentric sheaves are made in two parts, bolted together, so that they may be removed easily without dismounting the shaft. the eccentric is in principle nothing more than a crank pin so exaggerated as to be larger than the shaft of the crank. its convenience lies in the fact that it may be mounted at any point on a shaft, whereas a crank can be situated at an end only, if it is not actually a v-shaped bend in the shaft itself--in which case its position is of course permanent. setting of the slide-valve and eccentric. the subject of valve-setting is so extensive that a full exposition might weary the reader, even if space permitted its inclusion. but inasmuch as the effectiveness of a reciprocating engine depends largely on the nature and arrangement of the valves, we will glance at some of the more elementary principles. [illustration: fig. .] [illustration: fig. .] in fig. we see in section the slide-valve, the ports of the cylinder, and part of the piston. to the right are two lines at right angles--the thicker, c, representing the position of the crank; the thinner, e, that of the eccentric. (the position of an eccentric is denoted diagrammatically by a line drawn from the centre of the crank shaft through the centre of the sheave.) the edges of the valve are in this case only broad enough to just cover the ports--that is, they have no _lap_. the piston is about to commence its stroke towards the left; and the eccentric, which is set at an angle of ° in _advance_ of the crank, is about to begin opening the left-hand port. by the time that c has got to the position originally occupied by e, e will be horizontal (fig. )--that is, the eccentric will have finished its stroke towards the left; and while c passes through the next right angle the valve will be closing the left port, which will cease to admit steam when the piston has come to the end of its travel. the operation is repeated on the right-hand side while the piston returns. [illustration: fig. .] it must be noticed here--( ) that steam is admitted at full pressure _all through_ the stroke; ( ) that admission begins and ends simultaneously with the stroke. now, in actual practice it is necessary to admit steam before the piston has ended its travel, so as to _cushion_ the violence of the sudden change of direction of the piston, its rod, and other moving parts. to effect this, the eccentric is set more than ° in advance--that is, more than what the engineers call _square_. fig. shows such an arrangement. the angle between e and e^ is called the _angle of advance_. referring to the valve, you will see that it has opened an appreciable amount, though the piston has not yet started on its rightwards journey. "lap" of the valve--expansion of steam. in the simple form of valve that appears in fig. , the valve faces are just wide enough to cover the steam ports. if the eccentric is not _square_ with the crank, the admission of steam lasts until the very end of the stroke; if set a little in advance--that is, given _lead_--the steam is cut off before the piston has travelled quite along the cylinder, and readmitted before the back stroke is accomplished. even with this lead the working is very uneconomical, as the steam goes to the exhaust at practically the same pressure as that at which it entered the cylinder. its property of _expansion_ has been neglected. but supposing that steam at lbs. pressure were admitted till half-stroke, and then suddenly cut off, the expansive nature of the steam would then continue to push the piston out until the pressure had decreased to lbs. per square inch, at which pressure it would go to the exhaust. now, observe that all the work done by the steam after the cut-off is so much power saved. the _average_ pressure on the piston is not so high as in the first case; still, from a given volume of lbs. pressure steam we get much more _work_. how the cut-off is managed. [illustration: fig. .--a slide-valve with "lap."] [illustration: fig. .] look at fig. . here we have a slide-valve, with faces much wider than the steam ports. the parts marked black, p p, are those corresponding to the faces of the valves shown in previous diagrams (p. ). the shaded parts, l l, are called the _lap_. by increasing the length of the lap we increase the range of expansive working. fig. shows the piston full to the left; the valve is just on the point of opening to admit steam behind the piston. the eccentric has a throw equal to the breadth of a port + the lap of the valve. that this must be so is obvious from a consideration of fig. , where the valve is at its central position. hence the very simple formula:--travel of valve = × (lap + breadth of port). the path of the eccentric's centre round the centre of the shaft is indicated by the usual dotted line (fig. ). you will notice that the "angle of advance," denoted by the arrow a, is now very considerable. by the time that the crank c has assumed the position of the line s, the eccentric has passed its dead point, and the valve begins to travel backwards, eventually returning to the position shown in fig. , and cutting off the steam supply while the piston has still a considerable part of its stroke to make. the steam then begins to work expansively, and continues to do so until the valve assumes the position shown in fig. . if the valve has to have "lead" to admit steam _before_ the end of the stroke to the other side of the piston, the _angle of advance_ must be increased, and the eccentric centre line would lie on the line e^ . therefore--total angle of advance = angle for _lap_ and angle for _lead_. limit of expansive working. theoretically, by increasing the _lap_ and cutting off the steam earlier and earlier in the stroke, we should economize our power more and more. but in practice a great difficulty is met with--namely, that _as the steam expands its temperature falls_. if the cut-off occurs early, say at one-third stroke, the great expansion will reduce the temperature of the metal walls of the cylinder to such an extent, that when the next spirt of steam enters from the other end a considerable proportion of the steam's energy will be lost by cooling. in such a case, the difference in temperature between admitted steam and exhausted steam is too great for economy. yet we want to utilize as much energy as possible. how are we to do it? compound engines. in the year , john elder, founder of the shipping firm of elder and co., glasgow, introduced the _compound_ engine for use on ships. the steam, when exhausted from the high-pressure cylinder, passed into another cylinder of equal stroke but larger diameter, where the expansion continued. in modern engines the expansion is extended to three and even four stages, according to the boiler pressure; for it is a rule that the higher the initial pressure is, the larger is the number of stages of expansion consistent with economical working. [illustration: fig. .--sketch of the arrangement of a triple-expansion marine engine. no valve gear or supports, etc., shown.] in fig. we have a triple-expansion marine engine. steam enters the high-pressure cylinder[ ] at, say, lbs. per square inch. it exhausts at lbs. into the large pipe , and passes to the intermediate cylinder, whence it is exhausted at lbs. or so through pipe to the low-pressure cylinder. finally, it is ejected at about lbs. per square inch to the condenser, and is suddenly converted into water; an act which produces a vacuum, and diminishes the back-pressure of the exhaust from cylinder c. in fact, the condenser exerts a _sucking_ power on the exhaust side of c's piston. arrangement of expansion engines. in the illustration the cranks are set at angles of °, or a third of a circle, so that one or other is always at or near the position of maximum turning power. where only two stages are used the cylinders are often arranged _tandem_, both pistons having a common piston rod and crank. in order to get a constant turning movement they must be mounted separately, and work cranks set at right angles to one another. compound locomotives. in mr. a. mallet introduced _compounding_ in locomotives; and the practice has been largely adopted. the various types of "compounds" may be classified as follows:--( ) one low-pressure and one high-pressure cylinder; ( ) one high-pressure and two low-pressure; ( ) one low-pressure and two high-pressure; ( ) two high-pressure and two low-pressure. the last class is very widely used in france, america, and russia, and seems to give the best results. where only two cylinders are used (and sometimes in the case of three and four), a valve arrangement permits the admission of high-pressure steam to both high and low-pressure cylinders for starting a train, or moving it up heavy grades. reversing gears. [illustration: figs. , , .--showing how a reversing gear alters the position of the slide-valve.] the engines of a locomotive or steamship must be reversible--that is, when steam is admitted to the cylinders, the engineer must be able to so direct it through the steam-ways that the cranks may turn in the desired direction. the commonest form of reversing device (invented by george stephenson) is known as stephenson's link gear. in fig. we have a diagrammatic presentment of this gear. e^ and e^ are two eccentrics set square with the crank at opposite ends of a diameter. their rods are connected to the ends of a link, l, which can be raised and lowered by means of levers (not shown). b is a block which can partly revolve on a pin projecting from the valve rod, working through a guide, g. in fig. the link is half raised, or in "mid-gear," as drivers say. eccentric e^ has pushed the lower end of the link fully back; e^ has pulled it fully forward; and since any movement of the one eccentric is counterbalanced by the opposite movement of the other, rotation of the eccentrics would not cause the valve to move at all, and no steam could be admitted to the cylinder. let us suppose that fig. denotes one cylinder, crank, rods, etc., of a locomotive. the crank has come to rest at its half-stroke; the reversing lever is at the mid-gear notch. if the engineer desires to turn his cranks in an anti-clockwise direction, he _raises_ the link, which brings the rod of e^ into line with the valve rod and presses the block _backwards_ till the right-hand port is uncovered (fig. ). if steam be now admitted, the piston will be pushed towards the left, and the engine will continue to run in an anti-clockwise direction. if, on the other hand, he wants to run the engine the other way, he would _drop_ the link, bringing the rod of e^ into line with the valve rod, and drawing v _forward_ to uncover the rear port (fig. ). in either case the eccentric working the end of the link remote from b has no effect, since it merely causes that end to describe arcs of circles of which b is the centre. "linking up." if the link is only partly lowered or raised from the central position it still causes the engine to run accordingly, but the movement of the valve is decreased. when running at high speed the engineer "links up" his reversing gear, causing his valves to cut off early in the stroke, and the steam to work more expansively than it could with the lever at _full_, or _end_, gear; so that this device not only renders an engine reversible, but also gives the engineer an absolute command over the expansion ratio of the steam admitted to the cylinder, and furnishes a method of cutting off the steam altogether. in figs. , , , the valve has no lap and the eccentrics are set square. in actual practice the valve faces would have "lap" and the eccentric "lead" to correspond; but for the sake of simplicity neither is shown. other gears. in the gooch gear for reversing locomotives the link does not shift, but the valve rod and its block is raised or lowered. the allan gear is so arranged that when the link is raised the block is lowered, and _vice versâ_. these are really only modifications of stephenson's principle--namely, the employment of _two_ eccentrics set at equal angles to and on opposite sides of the crank. there are three other forms of link-reversing gear, and nearly a dozen types of _radial_ reversing devices; but as we have already described the three most commonly used on locomotives and ships, there is no need to give particulars of these. before the introduction of stephenson's gear a single eccentric was used for each cylinder, and to reverse the engine this eccentric had to be loose on the axle. "a lever and gear worked by a treadle on the footplate controlled the position of the eccentrics. when starting the engine, the driver put the eccentrics out of gear by the treadle; then, by means of a lever he raised the small-ends[ ] of the eccentric rods, and, noting the position of the cranks, or, if more convenient, the balance weight in the wheels, he, by means of another handle, moved the valves to open the necessary ports to steam and worked them by hand until the engine was moving; then, with the treadle, he threw the eccentrics over to engage the studs, at the same time dropping the small-ends of the rods to engage pins upon the valve spindles, so that they continued to keep up the movement of the valve."[ ] one would imagine that in modern shunting yards such a device would somewhat delay operations! piston valves. in marine engines, and on many locomotives and some stationary engines, the d-valve (shown in figs. - ) is replaced by a piston valve, or circular valve, working up and down in a tubular seating. it may best be described as a rod carrying two pistons which correspond to the faces of a d-valve. instead of rectangular ports there are openings in the tube in which the piston valve moves, communicating with the steam-ways into the cylinder and with the exhaust pipe. in the case of the d-valve the pressure above it is much greater than that below, and considerable friction arises if the rubbing faces are not kept well lubricated. the piston valve gets over this difficulty, since such steam as may leak past it presses on its circumference at all points equally. speed governors. [illustration: fig. .--a speed governor.] practically all engines except locomotives and those known as "donkey-engines"--used on cranes--are fitted with some device for keeping the rotatory speed of the crank constant within very narrow limits. perhaps you have seen a pair of balls moving round on a seating over the boiler of a threshing-engine. they form part of the "governor," or speed-controller, shown in principle in fig. . a belt driven by a pulley on the crank shaft turns a small pulley, p, at the foot of the governor. this transmits motion through two bevel-wheels, g, to a vertical shaft, from the top of which hang two heavy balls on links, k k. two more links, l l, connect the balls with a weight, w, which has a deep groove cut round it at the bottom. when the shaft revolves, the balls fly outwards by centrifugal force, and as their velocity increases the quadrilateral figure contained by the four links expands laterally and shortens vertically. the angles between k k and l l become less and less obtuse, and the weight w is drawn upwards, bringing with it the fork c of the rod a, which has ends engaging with the groove. as c rises, the other end of the rod is depressed, and the rod b depresses rod o, which is attached to the spindle operating a sort of shutter in the steam-pipe. consequently the supply of steam is throttled more and more as the speed increases, until it has been so reduced that the engine slows, and the balls fall, opening the valve again. fig. shows the valve fully closed. this form of governor was invented by james watt. a spring is often used instead of a weight, and the governor is arranged horizontally so that it may be driven direct from the crank shaft without the intervention of bevel gearing. [illustration: fig. .] the hartwell governor employs a link motion. you must here picture the balls raising and lowering the _free end_ of the valve rod, which carries a block moving in a link connected with the eccentric rod. the link is pivoted at the upper end, and the eccentric rod is attached to the lower. when the engine is at rest the end of the valve rod and its block are dropped till in a line with the eccentric rod; but when the machinery begins to work the block is gradually drawn up by the governor, diminishing the movement of the valve, and so shortening the period of steam admission to the cylinder. governors are of special importance where the _load_ of an engine is constantly varying, as in the case of a sawmill. a good governor will limit variation of speed within two per cent.--that is, if the engine is set to run at revolutions a minute, it will not allow it to exceed or fall below . in _very_ high-speed engines the governing will prevent variation of less than one per cent., even when the load is at one instant full on, and the next taken completely off. marine governors. these must be more quick-acting than those used on engines provided with fly-wheels, which prevent very sudden variations of speed. the screw is light in proportion to the engine power, and when it is suddenly raised from the water by the pitching of the vessel, the engine would race till the screw took the water again, unless some regulating mechanism were provided. many types of marine governors have been tried. the most successful seems to be one in which water is being constantly forced by a pump driven off the engine shaft into a cylinder controlling a throttle-valve in the main steam-pipe. the water escapes through a leak, which is adjustable. as long as the speed of the engine is normal, the water escapes from the cylinder as fast as it is pumped in, and no movement of the piston results; but when the screw begins to race, the pump overcomes the leak, and the piston is driven out, causing a throttling of the steam supply. condensers. the _condenser_ serves two purposes:--( ) it makes it possible to use the same water over and over again in the boilers. on the sea, where fresh water is not obtainable in large quantities, this is a matter of the greatest importance. ( ) it adds to the power of a compound engine by exerting a back pull on the piston of the low-pressure cylinder while the steam is being exhausted. [illustration: fig. .--the marine condenser.] fig. is a sectional illustration of a marine condenser. steam enters the condenser through the large pipe e, and passes among a number of very thin copper tubes, through which sea-water is kept circulating by a pump. the path of the water is shown by the featherless arrows. it comes from the pump through pipe a into the lower part of a large cap covering one end of the condenser and divided transversely by a diaphragm, d. passing through the pipes, it reaches the cap attached to the other end, and flows back through the upper tubes to the outlet c. this arrangement ensures that, as the steam condenses, it shall meet colder and colder tubes, and finally be turned to water, which passes to the well through the outlet f. in some condensers the positions of steam and water are reversed, steam going through the tubes outside which cold water circulates. [ ] also called _ports_. [ ] the bores of the cylinders are in the proportion of : : . the stroke of all three is the same. [ ] the ends furthest from the eccentric. [ ] "the locomotive of to-day," p. . chapter iii. the steam turbine. how a turbine works--the de laval turbine--the parsons turbine--description of the parsons turbine--the expansive action of steam in a parsons turbine--balancing the thrust--advantages of the marine turbine. more than two thousand years ago hero of alexandria produced the first apparatus to which the name of steam-engine could rightly be given. its principle was practically the same as that of the revolving jet used to sprinkle lawns during dry weather, steam being used in the place of water. from the top of a closed cauldron rose two vertical pipes, which at their upper ends had short, right-angle bends. between them was hung a hollow globe, pivoted on two short tubes projecting from its sides into the upright tubes. two little l-shaped pipes projected from opposite sides of the globe, at the ends of a diameter, in a plane perpendicular to the axis. on fire being applied to the cauldron, steam was generated. it passed up through the upright, through the pivots, and into the globe, from which it escaped by the two l-shaped nozzles, causing rapid revolution of the ball. in short, the first steam-engine was a turbine. curiously enough, we have reverted to this primitive type (scientifically developed, of course) in the most modern engineering practice. how a turbine works. in reciprocating--that is, cylinder--engines steam is admitted into a chamber and the door shut behind it, as it were. as it struggles to expand, it forces out one of the confining walls--that is, the piston--and presently the door opens again, and allows it to escape when it has done its work. in hero's toy the impact of the issuing molecules against other molecules that have already emerged from the pipes was used. one may compare the reaction to that exerted by a thrown stone on the thrower. if the thrower is standing on skates, the reaction of the stone will cause him to glide backwards, just as if he had pushed off from some fixed object. in the case of the _reaction_--namely, the hero-type--turbine the nozzle from which the steam or water issues moves, along with bodies to which it may be attached. in _action_ turbines steam is led through fixed nozzles or steam-ways, and the momentum of the steam is brought to bear on the surfaces of movable bodies connected with the shaft. the de laval turbine. in its earliest form this turbine was a modification of hero's. the wheel was merely a pipe bent in s form, attached at its centre to a hollow vertical shaft supplied with steam through a stuffing-box at one extremity. the steam blew out tangentially from the ends of the s, causing the shaft to revolve rapidly and work the machinery (usually a cream separator) mounted on it. this motor proved very suitable for dairy work, but was too wasteful of steam to be useful where high power was needed. [illustration: fig. .--the wheel and nozzles of a de laval turbine.] in the de laval turbine as now constructed the steam is blown from stationary nozzles against vanes mounted on a revolving wheel. fig. shows the nozzles and a turbine wheel. the wheel is made as a solid disc, to the circumference of which the vanes are dovetailed separately in a single row. each vane is of curved section, the concave side directed towards the nozzles, which, as will be gathered from the "transparent" specimen on the right of our illustration, gradually expand towards the mouth. this is to allow the expansion of the steam, and a consequent gain of velocity. as it issues, each molecule strikes against the concave face of a vane, and, while changing its direction, is robbed of its kinetic energy, which passes to the wheel. to turn once more to a stone-throwing comparison, it is as if a boy were pelting the wheel with an enormous number of tiny stones. now, escaping high-pressure steam moves very fast indeed. to give figures, if it enters the small end of a de laval nozzle at lbs. per square inch, it will leave the big end at a velocity of miles per _minute_--that is, at a speed which would take it right round the world in - / hours! the wheel itself would not move at more than about one-third of this speed as a maximum.[ ] but even so, it may make as many as , revolutions per minute. a mechanical difficulty is now encountered--namely, that arising from vibration. no matter how carefully the turbine wheel may be balanced, it is practically impossible to make its centre of gravity coincide exactly with the central point of the shaft; in other words, the wheel will be a bit--perhaps only a tiny fraction of an ounce--heavier on one side than the other. this want of truth causes vibration, which, at the high speed mentioned, would cause the shaft to knock the bearings in which it revolves to pieces, if--and this is the point--those bearings were close to the wheel m. de laval mounted the wheel on a shaft long enough between the bearings to "whip," or bend a little, and the difficulty was surmounted. the normal speed of the turbine wheel is too high for direct driving of some machinery, so it is reduced by means of gearing. to dynamos, pumps, and air-fans it is often coupled direct. the parsons turbine. at the grand naval review held in in honour of queen victoria's diamond jubilee, one of the most noteworthy sights was the little _turbinia_ of - / tons burthen, which darted about among the floating forts at a speed much surpassing that of the fastest "destroyer." inside the nimble little craft were engines developing , horse power, without any of the clank and vibration which usually reigns in the engine-room of a high-speed vessel. the _turbinia_ was the first turbine-driven boat, and as such, even apart from her extraordinary pace, she attracted great attention. since the parsons turbine has been installed on many ships, including several men-of-war, and it seems probable that the time is not far distant when reciprocating engines will be abandoned on all high-speed craft. description of the parsons turbine. [illustration: fig. .--section of a parsons turbine.] the essential parts of a parsons turbine are:--( ) the shaft, on which is mounted ( ) the drum; ( ) the cylindrical casing inside which the drum revolves; ( ) the vanes on the drum and casing; ( ) the balance pistons. fig. shows a diagrammatic turbine in section. the drum, it will be noticed, increases its diameter in three stages, d^ , d^ , d^ , towards the right. from end to end it is studded with little vanes, m m, set in parallel rings small distances apart. each vane has a curved section (see fig. ), the hollow side facing towards the left. the vanes stick out from the drum like short spokes, and their outer ends almost touch the casing. to the latter are attached equally-spaced rings of fixed vanes, f f, pointing inwards towards the drum, and occupying the intervals between the rings of moving vanes. their concave sides also face towards the left, but, as seen in fig. , their line of curve lies the reverse way to that of m m. steam enters the casing at a, and at once rushes through the vanes towards the outlet at b. it meets the first row of fixed vanes, and has its path so deflected that it strikes the ring of moving (or drum) vanes at the most effective angle, and pushes them round. it then has its direction changed by the ring of f f, so that it may treat the next row of m m in a similar fashion. [illustration: fig. .--blades or vanes of a parsons turbine.] [illustration: one of the low-pressure turbines of the _carmania_, in casing. its size will be inferred from comparison with the man standing near the end of the casing.] the expansive action of steam in a turbine. on reaching the end of d^ it enters the second, or intermediate, set of vanes. the drum here is of a greater diameter, and the blades are longer and set somewhat farther apart, to give a freer passage to the now partly expanded steam, which has lost pressure but gained velocity. the process of movement is repeated through this stage; and again in d^ , the low-pressure drum. the steam then escapes to the condenser through b, having by this time expanded very many times; and it is found advisable, for reasons explained in connection with compound steam-engines, to have a separate turbine in an independent casing for the extreme stages of expansion. the vanes are made of brass. in the turbines of the _carmania_, the huge cunard liner, , , vanes are used. the largest diameter of the drums is feet, and each low-pressure turbine weighs tons. balancing of thrust. the push exerted by the steam on the blades not only turns the drum, but presses it in the direction in which the steam flows. this end thrust is counterbalanced by means of the "dummy" pistons, p^ , p^ , p^ . each dummy consists of a number of discs revolving between rings projecting from the casing, the distance between discs and rings being so small that but little steam can pass. in the high-pressure compartment the steam pushes p^ to the left with the same pressure as it pushes the blades of d^ to the right. after completing the first stage it fills the passage c, which communicates with the second piston, p^ , and the pressure on that piston negatives the thrust on d^ . similarly, the passage e causes the steam to press equally on p^ and the vanes of d^ . so that the bearings in which the shaft revolves have but little thrust to take. this form of compensation is necessary in marine as well as in stationary turbines. in the former the dummy pistons are so proportioned that the forward thrust given by them and the screw combined is almost equal to the thrust aft of the moving vanes. [illustration: one of the turbine drums of the _carmania_. note the rows of vanes. the drum is here being tested for perfect balance on two absolutely level supports.] advantages of the marine turbine. ( .) absence of vibration. reciprocating engines, however well balanced, cause a shaking of the whole ship which is very unpleasant to passengers. the turbine, on the other hand, being almost perfectly balanced, runs so smoothly at the highest speeds that, if the hand be laid on the covering, it is sometimes almost impossible to tell whether the machinery is in motion. as a consequence of this smooth running there is little noise in the engine-room--a pleasant contrast to the deafening roar of reciprocating engines. ( .) turbines occupy less room. ( .) they are more easily tended. ( .) they require fewer repairs, since the rubbing surfaces are very small as compared to those of reciprocating engines. ( .) they are more economical at high speeds. it must be remembered that a turbine is essentially meant for high speeds. if run slowly, the steam will escape through the many passages without doing much work. owing to its construction, a turbine cannot be reversed like a cylinder engine. it therefore becomes necessary to fit special astern turbines to one or more of the screw shafts, for use when the ship has to be stopped or moved astern. under ordinary conditions these turbines revolve idly in their cases. the highest speed ever attained on the sea was the forty-two miles per hour of the unfortunate _viper_, a turbine destroyer which developed , horse power, though displacing only tons. this velocity would compare favourably with that of a good many expresses on certain railways that we could name. in the future thirty miles an hour will certainly be attained by turbine-driven liners. [ ] even at this speed the wheel has a circumferential velocity of two-thirds that of a bullet shot from a lee-metford rifle. a vane weighing only grains (about / oz.) exerts under these conditions a centrifugal pull of cwt. on the wheel! chapter iv. the internal-combustion engine. the meaning of the term--action of the internal-combustion engine--the motor car--the starting-handle--the engine--the carburetter--ignition of the charge--advancing the spark--governing the engine--the clutch--the gear-box--the compensating gear--the silencer--the brakes--speed of cars. the meaning of the term "internal-combustion engine." in the case of a steam-boiler the energy of combustion is transmitted to water inside an air-tight vessel. the fuel does not actually touch the "working fluid." in the gas or oil engine the fuel is brought into contact and mixed with the working fluid, which is air. it combines suddenly with it in the cylinder, and heat energy is developed so rapidly that the act is called an explosion. coal gas, mineral oils, alcohol, petrol, etc., all contain hydrogen and carbon. if air, which contributes oxygen, be added to any of these in due proportion, the mixture becomes highly explosive. on a light being applied, oxygen and carbon unite, also hydrogen and oxygen, and violent heat is generated, causing a violent molecular bombardment of the sides of the vessel containing the mixture. now, if the mixture be _compressed_ it becomes hotter and hotter, until a point is reached at which it ignites spontaneously. early gas-engines did not compress the charge before ignition. alphonse beau de rochas, a frenchman, first thought of making the piston of the engine squeeze the mixture before ignition; and from the year , when he proposed this innovation, the success of the internal-combustion engine may be said to date. [illustration] [illustration: fig. .--showing the four strokes that the piston of a gas-engine makes during one "cycle."] action of the engine. the gas-engine, the oil-engine, and the motor-car engine are similar in general principles. the cylinder has, instead of a slide-valve, two, or sometimes three, "mushroom" valves, which may be described as small and thick round plates, with bevelled edges, mounted on the ends of short rods, called stems. these valves open into the cylinder, upwards, downwards, or horizontally, as the case may be; being pushed in by cams projecting from a shaft rotated by the engine. for the present we will confine our attention to the series of operations which causes the engine to work. this series is called the beau de rochas, or otto, cycle, and includes four movements of the piston. reference to fig. will show exactly what happens in a gas-engine--( ) the piston moves from left to right, and just as the movement commences valves g (gas) and a (air) open to admit the explosive mixture. by the time that p has reached the end of its travel these valves have closed again. ( ) the piston returns to the left, compressing the mixture, which has no way of escape open to it. at the end of the stroke the charge is ignited by an incandescent tube i (in motor car and some stationary engines by an electric spark), and ( ) the piston flies out again on the "explosion" stroke. before it reaches the limit position, valve e (exhaust) opens, and ( ) the piston flies back under the momentum of the fly-wheel, driving out the burnt gases through the still open e. the "cycle" is now complete. there has been suction, compression (including ignition), combustion, and exhaustion. it is evident that a heavy fly-wheel must be attached to the crank shaft, because the energy of one stroke (the explosion) has to serve for the whole cycle; in other words, for two complete revolutions of the crank. a single-cylinder steam-engine develops an impulse every half-turn--that is, four times as often. in order to get a more constant turning effect, motor cars have two, three, four, six, and even eight cylinders. four-cylinder engines are at present the most popular type for powerful cars. the motor car. [illustration: fig. .--plan of the chassis of a motor car.] we will now proceed to an examination of the motor car, which, in addition to mechanical apparatus for the transmission of motion to the driving-wheels, includes all the fundamental adjuncts of the internal-combustion engine.[ ] fig. is a bird's-eye view of the _chassis_ (or "works" and wheels) of a car, from which the body has been removed. starting at the left, we have the handle for setting the engine in motion; the engine (a two-cylinder in this case); the fly-wheel, inside which is the clutch; the gear-box, containing the cogs for altering the speed of revolution of the driving-wheels relatively to that of the engine; the propeller shaft; the silencer, for deadening the noise of the exhaust; and the bevel-gear, for turning the driving-wheels. in the particular type of car here considered you will notice that a "direct," or shaft, drive is used. the shaft has at each end a flexible, or "universal," joint, which allows the shaft to turn freely, even though it may not be in a line with the shaft projecting from the gear-box. it must be remembered that the engine and gear-box are mounted on the frame, between which and the axles are springs, so that when the car bumps up and down, the shaft describes part of a circle, of which the gear-box end is the centre. an alternative method of driving is by means of chains, which run round sprocket (cog) wheels on the ends of a shaft crossing the frame just behind the gear-box, and round larger sprockets attached to the hubs of the driving-wheels. in such a case the axles of the driving-wheel are fixed to the springs, and the wheels revolve round them. where a cardan (shaft) drive is used the axles are attached rigidly to the wheels at one end, and extend, through tubes fixed to the springs, to bevel-wheels in a central compensating-gear box (of which more presently). several parts--the carburetter, tanks, governor, and pump--are not shown in the general plan. these will be referred to in the more detailed account that follows. the starting-handle. [illustration: fig. .--the starting-handle.] fig. gives the starting-handle in part section. the handle h is attached to a tube which terminates in a clutch, c. a powerful spring keeps c normally apart from a second clutch, c^ , keyed to the engine shaft. when the driver wishes to start the engine he presses the handle towards the right, brings the clutches together, and turns the handle in a clockwise direction. as soon as the engine begins to fire, the faces of the clutches slip over one another. the engine. [illustration: fig. .--end and cross sections of a two-cylinder motor.] we next examine the two-cylinder engine (fig. ). each cylinder is surrounded by a water-jacket, through which water is circulated by a pump[ ] (fig. ). the heat generated by combustion is so great that the walls of the cylinder would soon become red-hot unless some of the heat were quickly carried away. the pistons are of "trunk" form--that is, long enough to act as guides and absorb the oblique thrust of the piston rods. three or more piston rings lying in slots (not shown) prevent the escape of gas past the piston. it is interesting to notice that the efficiency of an internal-combustion engine depends so largely on the good fit of these moving parts, that cylinders, pistons, and rings must be exceedingly true. a good firm will turn out standard parts which are well within / of an inch of perfect truth. it is also a wonderful testimony to the quality of the materials used that, if properly looked after, an engine which has made many millions of revolutions, at the rate of , to , per minute, often shows no appreciable signs of wear. in one particular test an engine was run _continuously for several months_, and at the end of the trial was in absolutely perfect condition. the cranks revolve in an oil-tight case (generally made of aluminium), and dip in oil, which they splash up into the cylinder to keep the piston well lubricated. the plate, p p, through a slot in which the piston rod works, prevents an excess of oil being flung up. channels are provided for leading oil into the bearings. the cranks are ° apart. while one piston is being driven out by an explosion, the other is compressing its charge prior to ignition, so that the one action deadens the other. therefore two explosions occur in one revolution of the cranks, and none during the next revolution. if both cranks were in line, the pistons would move together, giving one explosion each revolution. [illustration: fig. .--showing how the water which cools the cylinders is circulated.] the valve seats, and the inlet and exhaust pipes, are seen in section. the inlet valve here works automatically, being pulled in by suction; but on many engines--on all powerful engines--the inlet, like the exhaust valve, is lifted by a cam, lest it should stick or work irregularly. three dotted circles show a, a cog on the crank shaft; b, a "lay" cog, which transmits motion to c, on a short shaft rotating the cam that lifts the exhaust valve. c, having twice as many teeth as a, revolves at half its rate. this ensures that the valve shall be lifted only once in two revolutions of the crank shaft to which it is geared. the cogs are timed, or arranged, so that the cam begins to lift the valve when the piston has made about seven-eighths of its explosion stroke, and closes the valve at the end of the exhaust stroke. the carburetter. a motor car generally uses petrol as its fuel. petrol is one of the more volatile products of petroleum, and has a specific gravity of about --that is, volume for volume, its weight is to that of water in the proportion of to , . it is extremely dangerous, as it gives off an inflammable gas at ordinary temperatures. benzine, which we use to clean clothes, is practically the same as petrol, and should be treated with equal care. the function of a _carburetter_ is to reduce petrol to a very fine spray and mix it with a due quantity of air. the device consists of two main parts (fig. )--the _float chamber_ and the _jet chamber_. in the former is a contrivance for regulating the petrol supply. a float--a cork, or air-tight metal box--is arranged to move freely up and down the stem of a needle-valve, which closes the inlet from the tank. at the bottom of the chamber are two pivoted levers, w w, which, when the float rests on them, tip up and lift the valve. petrol flows in and raises the float. this allows the valve to sink and cut off the supply. if the valve is a good fit and the float is of the correct weight, the petrol will never rise higher than the tip of the jet g. [illustration: fig. .--section of a carburetter.] the suction of the engine makes petrol spirt through the jet (which has a very small hole in its end) and atomize itself against a spraying-cone, a. it then passes to the engine inlet pipe through a number of openings, after mixing with air entering from below. an extra air inlet, controllable by the driver, is generally added, unless the carburetter be of a type which automatically maintains constant proportions of air and vapour. the jet chamber is often surrounded by a jacket, through which part of the hot exhaust gases circulate. in cold weather especially this is a valuable aid to vaporization. [illustration: fig. .--sketch of the electrical ignition arrangements on a motor car.] ignition of the charge. all petrol-cars now use electrical ignition. there are two main systems--( ) by an accumulator and induction coil; ( ) _magneto ignition_, by means of a small dynamo driven by the engine. a general arrangement of the first is shown in fig. . a disc, d, of some insulating material--fibre or vulcanite--is mounted on the cam, or half-speed, shaft. into the circumference is let a piece of brass, called the contact-piece, through which a screw passes to the cam shaft. a movable plate, m p, which can be rotated concentrically with d through part of a circle, carries a "wipe" block at the end of a spring, which presses it against d. the spring itself is attached to an insulated plate. when the revolution of d brings the wipe and contact together, current flows from the accumulator through switch s to the wipe; through the contact-piece to c; from c to m p and the induction coil; and back to the accumulator. this is the _primary, or low-tension, circuit_. a _high-tension_ current is induced by the coil in the _secondary_ circuit, indicated by dotted lines.[ ] in this circuit is the sparking-plug (see fig. ), having a central insulated rod in connection with one terminal of the secondary coil. between it and a bent wire projecting from the iron casing of the plug (in contact with the other terminal of the secondary coil through the metal of the engine, to which one wire of the circuit is attached) is a small gap, across which the secondary current leaps when the primary current is broken by the wipe and contact parting company. the spark is intensely hot, and suffices to ignite the compressed charge in the cylinder. [illustration: fig. .--section of a sparking-plug.] advancing the spark. we will assume that the position of w (in fig. ) is such that the contact touches w at the moment when the piston has just completed the compression stroke. now, the actual combustion of the charge occupies an appreciable time, and with the engine running at high speed the piston would have travelled some way down the cylinder before the full force of the explosion was developed. but by raising lever l, the position of w may be so altered that contact is made slightly _before_ the compression stroke is complete, so that the charge is fairly alight by the time the piston has altered its direction. this is called _advancing_ the spark. governing the engine. there are several methods of controlling the speed of internal-combustion engines. the operating mechanism in most cases is a centrifugal ball-governor. when the speed has reached the fixed limit it either ( ) raises the exhaust valve, so that no fresh charges are drawn in; ( ) prevents the opening of the inlet valve; or ( ) throttles the gas supply. the last is now most commonly used on motor cars, in conjunction with some device for putting it out of action when the driver wishes to exceed the highest speed that it normally permits. [illustration: fig. .--one form of governor used on motor cars.] a sketch of a neat governor, with regulating attachment, is given in fig. . the governor shaft is driven from the engine. as the balls, b b, increase their velocity, they fly away from the shaft and move the arms, a a, and a sliding tube, c, towards the right. this rocks the lever r, and allows the valves in the inlet pipe to close and reduce the supply of air and gas. a wedge, w, which can be raised or lowered by lever l, intervenes between the end of r and the valve stem. if this lever be lifted to its highest position, the governing commences at a lower speed, as the valve then has but a short distance to travel before closing completely. for high speeds the driver depresses l, forces the wedge down, and so minimizes the effect of the governor. the clutch. the engine shaft has on its rear end the fly-wheel, which has a broad and heavy rim, turned to a conical shape inside. close to this, revolving loosely on the shaft, is the clutch plate, a heavy disc with a broad edge so shaped as to fit the inside of a fly-wheel. it is generally faced with leather. a very strong spring presses the plate into the fly-wheel, and the resulting friction is sufficient to prevent any slip. projections on the rear of the clutch engage with the gear-box shaft. the driver throws out the clutch by depressing a lever with his foot. some clutches dispense with the leather lining. these are termed _metal to metal_ clutches. the gear-box. we now come to a very interesting detail of the motor car, the gear-box. the steam-engine has its speed increased by admitting more steam to the cylinders. but an explosion engine must be run at a high speed to develop its full power, and when heavier work has to be done on a hill it becomes necessary to alter the speed ratio of engine to driving-wheels. our illustration (fig. ) gives a section of a gear-box, which will serve as a typical example. it provides three forward speeds and one reverse. to understand how it works, we must study the illustration carefully. pinion is mounted on a hollow shaft turned by the clutch. into the hollow shaft projects the end of another shaft carrying pinions and . pinion slides up and down this shaft, which is square at this point, but round inside the _loose_ pinion . pinions and are keyed to a square secondary shaft, and are respectively always in gear with and ; but can be slid backwards and forwards so as to engage or disengage with . in the illustration no gear is "in." if the engine is working, revolves , turns , and revolves idly on its shaft. [illustration: fig. .--the gear-box of a motor car.] to get the lowest, or "first," speed the driver moves his lever and slides into gear with . the transmission then is: turns , turns , turns , turns the propeller shaft through the universal joint. for the second speed, and are disengaged, and is moved up the page, as it were, till projections on it interlock with slots in ; thus driving , , , , shaft. for the third, or "solid," speed, is pulled down into connection with , and couples the engine shaft direct to the propeller shaft. the "reverse" is accomplished by raising a long pinion, , which lies in the gear-box under and . the drive then is , , , , . there being an odd number of pinions now engaged, the propeller shaft turns in the reverse direction to that of the engine shaft. [illustration: fig. .] the compensating gear. every axle of a railway train carries a wheel at each end, rigidly attached to it. when rounding a corner the outside wheel has further to travel than the other, and consequently one or both wheels must slip. the curves are made so gentle, however, that the amount of slip is very small. but with a traction-engine, motor car, or tricycle the case is different, for all have to describe circles of very small diameter in proportion to the length of the vehicle. therefore in every case a _compensating gear_ is fitted, to allow the wheels to turn at different speeds, while permitting them both to drive. fig. is an exaggerated sketch of the gear. the axles of the moving wheels turn inside tubes attached to the springs and a central casing (not shown), and terminate in large bevel-wheels, c and d. between these are small bevels mounted on a shaft supported by the driving drum. if the latter be rotated, the bevels would turn c and d at equal speeds, assuming that both axles revolve without friction in their bearings. we will suppose that the drum is turned times a minute. now, if one wheel be held, the other will revolve times a minute; or, if one be slowed, the other will increase its speed by a corresponding amount. the _average_ speed remains . it should be mentioned that drum a has incorporated with it on the outside a bevel-wheel (not shown) rotated by a smaller bevel on the end of the propeller shaft. the silencer. the petrol-engine, as now used, emits the products of combustion at a high pressure. if unchecked, they expand violently, and cause a partial vacuum in the exhaust pipe, into which the air rushes back with such violence as to cause a loud noise. devices called _silencers_ are therefore fitted, to render the escape more gradual, and split it up among a number of small apertures. the simplest form of silencer is a cylindrical box, with a number of finely perforated tubes passing from end to end of it. the exhaust gases pouring into the box maintain a constant pressure somewhat higher than that of the atmosphere, but as the gases are escaping from it in a fairly steady stream the noise becomes a gentle hiss rather than a "pop." there are numerous types of silencers, but all employ this principle in one form or another. the brakes. every car carries at least two brakes of band pattern--one, usually worked by a side hand-lever, acting on the axle or hubs of the driving-wheel; the other, operated by the foot, acting on the transmission gear (see fig. ). the latter brake is generally arranged to withdraw the clutch simultaneously. tests have proved that even heavy cars can be pulled up in astonishingly short distances, considering their rate of travel. trials made in the united states with a touring car and a four-in-hand coach gave - / and feet respectively for the distance in which the speed could be reduced from sixteen miles per hour to zero. speed of cars. as regards speed, motor cars can rival the fastest express trains, even on long journeys. in fact, feats performed during the gordon-bennett and other races have equalled railway performances over equal distances. when we come to record speeds, we find a car, specially built for the purpose, covering a mile in less than half a minute. a speed of over miles an hour has actually been reached. engines of h.p. can now be packed into a vehicle scaling less than - / tons. even on touring cars are often found engines developing to h.p., which force the car up steep hills at a pace nothing less than astonishing. in the future the motor car will revolutionize our modes of life to an extent comparable to the changes effected by the advent of the steam-engine. even since , when the "man-with-the-flag" law was abolished in the british isles, the motor has reduced distances, opened up country districts, and generally quickened the pulses of the community in a manner which makes it hazardous to prophesy how the next generation will live. _note._--the author is much indebted to mr. wilfrid j. lineham, m. inst. c.e., for several of the illustrations which appear in the above chapter. [ ] steam-driven cars are not considered in this chapter, as their principle is much the same as that of the ordinary locomotive. [ ] on some cars natural circulation is used, the hot water flowing from the top of the cylinder to the tank, from which it returns, after being cooled, to the bottom of the cylinder. [ ] for explanation of the induction coil, see p. chapter v. electrical apparatus. what is electricity?--forms of electricity--magnetism--the permanent magnet--lines of force--electro-magnets--the electric bell--the induction coil--the condenser--transformation of current--uses of the induction coil. what is electricity? of the ultimate nature of electricity, as of that of heat and light, we are at present ignorant. but it has been clearly established that all three phenomena are but manifestations of the energy pervading the universe. by means of suitable apparatus one form can be converted into another form. the heat of fuel burnt in a boiler furnace develops mechanical energy in the engine which the boiler feeds with steam. the engine revolves a dynamo, and the electric current thereby generated can be passed through wires to produce mechanical motion, heat, or light. we must remain content, therefore, with assuming that electricity is energy or motion transmitted through the ether from molecule to molecule, or from atom to atom, of matter. scientific investigation has taught us how to produce it at will, how to harness it to our uses, and how to measure it; but not _what_ it is. that question may, perhaps, remain unanswered till the end of human history. a great difficulty attending the explanation of electrical action is this--that, except in one or two cases, no comparison can be established between it and the operation of gases and fluids. when dealing with the steam-engine, any ordinary intelligence soon grasps the principles which govern the use of steam in cylinders or turbines. the diagrams show, it is hoped, quite plainly "how it works." but electricity is elusive, invisible; and the greatest authorities cannot say what goes on at the poles of a magnet or on the surface of an electrified body. even the existence of "negative" and "positive" electricity is problematical. however, we see the effects, and we know that if one thing is done another thing happens; so that we are at least able to use terms which, while convenient, are not at present controverted by scientific progress. forms of electricity. rub a vulcanite rod and hold one end near some tiny pieces of paper. they fly to it, stick to it for a time, and then fall off. the rod was electrified--that is, its surface was affected in such a way as to be in a state of molecular strain which the contact of the paper fragments alleviated. by rubbing large surfaces and collecting the electricity in suitable receivers the strain can be made to relieve itself in the form of a violent discharge accompanied by a bright flash. this form of electricity is known as _static_. next, place a copper plate and a zinc plate into a jar full of diluted sulphuric acid. if a wire be attached to them a current of electricity is said to _flow_ along the wire. we must not, however, imagine that anything actually moves along inside the wire, as water, steam, or air, passes through a pipe. professor trowbridge says,[ ] "no other agency for transmitting power can be stopped by such slight obstacles as electricity. a thin sheet of paper placed across a tube conveying compressed air would be instantly ruptured. it would take a wall of steel at least an inch thick to stand the pressure of steam which is driving a , horse-power engine. a thin layer of dirt beneath the wheels of an electric car can prevent the current which propels the car from passing to the rail, and then back to the power-house." there would, indeed, be a puncture of the paper if the current had a sufficient voltage, or pressure; yet the fact remains that _current_ electricity can be very easily confined to its conductor by means of some insulating or nonconducting envelope. magnetism. the most familiar form of electricity is that known as magnetism. when a bar of steel or iron is magnetized, it is supposed that the molecules in it turn and arrange themselves with all their north-seeking poles towards the one end of the bar, and their south-seeking poles towards the other. if the bar is balanced freely on a pivot, it comes to rest pointing north and south; for, the earth being a huge magnet, its north pole attracts all the north-seeking poles of the molecules, and its south poles the south-seeking poles. (the north-_seeking_ pole of a magnet is marked n., though it is in reality the _south_ pole; for unlike poles are mutually attractive, and like poles repellent.) there are two forms of magnet--_permanent_ and _temporary_. if steel is magnetized, it remains so; but soft iron loses practically all its magnetism as soon as the cause of magnetization is withdrawn. this is what we should expect; for steel is more closely compacted than iron, and the molecules therefore would be able to turn about more easily.[ ] it is fortunate for us that this is so, since on the rapid magnetization and demagnetization of soft iron depends the action of many of our electrical mechanisms. the permanent magnet. magnets are either ( ) straight, in which case they are called bar magnets; or ( ) of horseshoe form, as in figs. and . by bending the magnet the two poles are brought close together, and the attraction of both may be exercised simultaneously on a bar of steel or iron. lines of force. in fig. are seen a number of dotted lines. these are called _lines of magnetic force_. if you lay a sheet of paper on a horseshoe magnet and sprinkle it with iron dust, you will at once notice how the particles arrange themselves in curves similar in shape to those shown in the illustration. it is supposed (it cannot be _proved_) that magnetic force streams away from the n. pole and describes a circular course through the air back to the s. pole. the same remark applies to the bar magnet. electrical magnets. [illustration: fig. .--permanent magnet, and the "lines of force" emanating from it.] if an insulated wire is wound round and round a steel or iron bar from end to end, and has its ends connected to the terminals of an electric battery, current rotates round the bar, and the bar is magnetized. by increasing the strength and volume of the current, and multiplying the number of turns of wire, the attractive force of the magnet is increased. now disconnect the wires from the battery. if of iron, the magnet at once loses its attractive force; but if of steel, it retains it in part. instead of a simple horseshoe-shaped bar, two shorter bars riveted into a plate are generally used for electromagnets of this type. coils of wire are wound round each bar, and connected so as to form one continuous whole; but the wire of one coil is wound in the direction opposite to that of the other. the free end of each goes to a battery terminal. in fig. you will notice that some of the "lines of force" are deflected through the iron bar a. they pass more easily through iron than through air; and will choose iron by preference. the attraction exercised by a magnet on iron may be due to the effort of the lines of force to shorten their paths. it is evident that the closer a comes to the poles of the magnet the less will be the distance to be travelled from one pole to the bar, along it, and back to the other pole. [illustration: fig. .--electro-magnet: a, armature; b, battery.] having now considered electricity in three of its forms--static, current, and rotatory--we will pass to some of its applications. the electric bell. a fit device to begin with is the electric bell, which has so largely replaced wire-pulled bells. these last cause a great deal of trouble sometimes, since if a wire snaps it may be necessary to take up carpets and floor-boards to put things right. their installation is not simple, for at every corner must be put a crank to alter the direction of the pull, and the cranks mean increased friction. but when electric wires have once been properly installed, there should be no need for touching them for an indefinite period. they can be taken round as many corners as you wish without losing any of their conductivity, and be placed wherever is most convenient for examination. one bell may serve a large number of rooms if an _indicator_ be used to show where the call was made from, by a card appearing in one of a number of small windows. before answering a call, the attendant presses in a button to return the card to its normal position. in fig. we have a diagrammatic view of an electric bell and current. when the bell-push is pressed in, current flows from the battery to terminal t^ , round the electro-magnet m, through the pillar p and flat steel springs s and b, through the platinum-pointed screw, and back to the battery through the push. the circulation of current magnetizes m, which attracts the iron armature a attached to the spring s, and draws the hammer h towards the gong. just before the stroke occurs, the spring b leaves the tip of the screw, and the circuit is broken, so that the magnet no longer attracts. h is carried by its momentum against the gong, and is withdrawn by the spring, until b once more makes contact, and the magnet is re-excited. the hammer vibrations recur many times a second as long as the push is pressed in. [illustration: fig. .--sketch of an electric-bell circuit.] the electric bell is used for so many purposes that they cannot all be noted. it plays an especially important part in telephonic installations to draw the attention of the subscribers, forms an item in automatic fire and burglar alarms, and is a necessary adjunct of railway signalling cabins. the induction or ruhmkorff coil. reference was made in connection with the electrical ignition of internal-combustion engines (p. ) to the _induction coil_. this is a device for increasing the _voltage_, or pressure, of a current. the two-cell accumulator carried in a motor car gives a voltage (otherwise called electro-motive force = e.m.f.) of · volts. if you attach a wire to one terminal of the accumulator and brush the loose end rapidly across the other terminal, you will notice that a bright spark passes between the wire and the terminal. in reality there are two sparks, one when they touch, and another when they separate, but they occur so closely together that the eye cannot separate the two impressions. a spark of this kind would not be sufficiently hot to ignite a charge in a motor cylinder, and a spark from the induction coil is therefore used. [illustration: fig. .--sketch of an induction coil.] we give a sketch of the induction coil in fig. . it consists of a core of soft iron wires round which is wound a layer of coarse insulated wire, denoted by the thick line. one end of the winding of this _primary_ coil is attached to the battery, the other to the base of a hammer, h, vibrating between the end of the core and a screw, s, passing through an upright, t, connected with the other terminal of the battery. the action of the hammer is precisely the same as that of the armature of an electric bell. outside the primary coil are wound many turns of a much finer wire completely insulated from the primary coil. the ends of this _secondary_ coil are attached to the objects (in the case of a motor car, the insulated wire of the sparking-plug and a wire projecting from its outer iron casing) between which a spark has to pass. as soon as h touches s the circuit is completed. the core becomes a powerful magnet with external lines of force passing from one pole to the other over and among the turns of the secondary coil. h is almost instantaneously attracted by the core, and the break occurs. the lines of force now (at least so it is supposed) sink into the core, cutting through the turns of the "secondary," and causing a powerful current to flow through them. the greater the number of turns, the greater the number of times the lines of force are cut, and the stronger is the current. if sufficiently intense, it jumps any gap in the secondary circuit, heating the intermediate air to a state of incandescence. the condenser. the sudden parting of h and s would produce strong sparking across the gap between them if it were not for the condenser, which consists of a number of tinfoil sheets separated by layers of paraffined paper. all the "odd" sheets are connected with t, all the "even" with t^ . now, the more rapid the extinction of magnetism in the core after "break" of the primary circuit, the more rapidly will the lines of force collapse, and the more intense will be the induced current in the secondary coil. the condenser diminishes the period of extinction very greatly, while lengthening the period of magnetization after the "make" of the primary current, and so decreasing the strength of the reverse current. transformation of current. the difference in the voltage of the primary and secondary currents depends on the length of the windings. if there are turns of wire in the primary, and , turns in the secondary, the voltage will be increased , times; so that a -volt current is "stepped up" to , volts. in the largest induction coils the secondary winding absorbs - miles of wire, and the spark given may be anything up to four feet in length. such a spark would pierce a glass plate two inches thick. it must not be supposed that an induction coil increases the _amount_ of current given off by a battery. it merely increases its pressure at the expense of its volume--stores up its energy, as it were, until there is enough to do what a low-tension flow could not effect. a fair comparison would be to picture the energy of the low-tension current as the momentum of a number of small pebbles thrown in succession at a door, say a minute. if you went on pelting the door for hours you might make no impression on it, but if you could knead every pebbles into a single stone, and throw these stones one per minute, you would soon break the door in. any intermittent current can be transformed as regards its intensity. you may either increase its pressure while decreasing its rate of flow, or _amperage_; or decrease its pressure and increase its flow. in the case that we have considered, a continuous battery current is rendered intermittent by a mechanical contrivance. but if the current comes from an "alternating" dynamo--that is, is already intermittent--the contact-breaker is not needed. there will be more to say about transformation of current in later paragraphs. uses of the induction coil. the induction coil is used--( .) for passing currents through glass tubes almost exhausted of air or containing highly rarefied gases. the luminous effects of these "geissler" tubes are very beautiful. ( .) for producing the now famous x or röntgen rays. these rays accompany the light rays given off at the negative terminal (cathode) of a vacuum tube, and are invisible to the eye unless caught on a fluorescent screen, which reduces their rate of vibration sufficiently for the eye to be sensitive to them. the röntgen rays have the peculiar property of penetrating many substances quite opaque to light, such as metals, stone, wood, etc., and as a consequence have proved of great use to the surgeon in localizing or determining the nature of an internal injury. they also have a deterrent effect upon cancerous growths. ( .) in wireless telegraphy, to cause powerful electric oscillations in the ether. ( .) on motor cars, for igniting the cylinder charges. ( .) for electrical massage of the body. [ ] "what is electricity?" p. . [ ] if a magnetized bar be heated to white heat and tapped with a hammer it loses its magnetism, because the distance between the molecules has increased, and the molecules can easily return to their original positions. chapter vi. the electric telegraph. needle instruments--influence of current on the magnetic needle--method of reversing the current--sounding instruments--telegraphic relays--recording telegraphs--high-speed telegraphy. take a small pocket compass and wind several turns of fine insulated wire round the case, over the top and under the bottom. now lay the compass on a table, and turn it about until the coil is on a line with the needle--in fact, covers it. next touch the terminals of a battery with the ends of the wire. the needle at once shifts either to right or left, and remains in that position as long as the current flows. if you change the wires over, so reversing the direction of the current, the needle at once points in the other direction. it is to this conduct on the part of a magnetic needle when in a "magnetic field" that we owe the existence of the needle telegraph instrument. needle instruments. [illustration: fig. .--sketch of the side elevation of a wheatstone needle instrument.] probably the best-known needle instrument is the cooke-wheatstone, largely used in signal-boxes and in some post-offices. a vertical section of it is shown in fig. . it consists of a base, b, and an upright front, a, to the back of which are attached two hollow coils on either side of a magnetic needle mounted on the same shaft as a second dial needle, n, outside the front. the wires w w are connected to the telegraph line and to the commutator, a device which, when the operator moves the handle h to right and left, keeps reversing the direction of the current. the needles on both receiving and transmitting instruments wag in accordance with the movements of the handle. one or more movements form an alphabetical letter of the morse code. thus, if the needle points first to left, and then to right, and comes to rest in a normal position for a moment, the letter a is signified; right-left-left-left in quick succession = b; right-left-right-left = c, and so on. where a marking instrument is used, a dot signifies a "left," and a dash a right; and if a "sounder" is employed, the operator judges by the length of the intervals between the clicks. influence of current on a magnetic needle. [illustration: figs. , .--the coils of a needle instrument. the arrows show the direction taken by the current.] figs. and are two views of the coils and magnetic needle of the wheatstone instrument as they appear from behind. in fig. the current enters the left-hand coil from the left, and travels round and round it in a clockwise direction to the other end, whence it passes to the other coil and away to the battery. now, a coil through which a current passes becomes a magnet. its polarity depends on the direction in which the current flows. suppose that you are looking through the coil, and that the current enters it from your end. if the wire is wound in a clockwise direction, the s. pole will be nearest you; if in an anti-clockwise direction, the n. pole. in fig. the n. poles are at the right end of the coils, the s. poles at the left end; so the n. pole of the needle is attracted to the right, and the s. pole to the left. when the current is reversed, as in fig. , the needle moves over. if no current passes, it remains vertical. method of reversing the current. [illustration: fig. .--general arrangement of needle-instrument circuit. the shaded plates on the left (b and r) are in contact.] a simple method of changing the direction of the current in a two-instrument circuit is shown diagrammatically in fig. . the _principle_ is used in the wheatstone needle instrument. the battery terminals at each station are attached to two brass plates, a b, a^ b^ . crossing these at right angles (under a a^ and over b b^ ) are the flat brass springs, l r, l^ r^ , having buttons at their lower ends, and fixed at their upper ends to baseboards. when at rest they all press upwards against the plates a and a^ respectively. r and l^ are connected with the line circuit, in which are the coils of dials and , one at each station. l and r^ are connected with the earth-plates e e^ . an operator at station depresses r so as to touch b. current now flows from the battery to b, thence through r to the line circuit, round the coils of both dials through l^ a^ and r to earth-plate e^ , through the earth to e, and then back to the battery through l and a. the needles assume the position shown. to reverse the current the operator allows r to rise into contact with a, and depresses l to touch b. the course can be traced out easily. in the wheatstone "drop-handle" instrument (fig. ) the commutator may be described as an insulated core on which are two short lengths of brass tubing. one of these has rubbing against it a spring connected with the + terminal of the battery; the other has similar communication with the - terminal. projecting from each tube is a spike, and rising from the baseboard are four upright brass strips not quite touching the commutator. those on one side lead to the line circuit, those on the other to the earth-plate. when the handle is turned one way, the spikes touch the forward line strip and the rear earth strip, and _vice versâ_ when moved in the opposite direction. sounding instruments. sometimes little brass strips are attached to the dial plate of a needle instrument for the needle to strike against. as these give different notes, the operator can comprehend the message by ear alone. but the most widely used sounding instrument is the morse sounder, named after its inventor. for this a reversible current is not needed. the receiver is merely an electro-magnet (connected with the line circuit and an earth-plate) which, when a current passes, attracts a little iron bar attached to the middle of a pivoted lever. the free end of the lever works between two stops. every time the circuit is closed by the transmitting key at the sending station the lever flies down against the lower stop, to rise again when the circuit is broken. the duration of its stay decides whether a "long" or "short" is meant. telegraphic relays. [illustration: fig. .--section of a telegraph wire insulator on its arm. the shaded circle is the line wire, the two blank circles indicate the wire which ties the line wire to the insulator.] when an electric current has travelled for a long distance through a wire its strength is much reduced on account of the resistance of the wire, and may be insufficient to cause the electro-magnet of the sounder to move the heavy lever. instead, therefore, of the current acting directly on the sounder magnet, it is used to energize a small magnet, or _relay_, which pulls down a light bar and closes a second "local" circuit--that is, one at the receiver end--worked by a separate battery, which has sufficient power to operate the sounder. recording telegraphs. by attaching a small wheel to the end of a morse-sounder lever, by arranging an ink-well for the wheel to dip into when the end falls, and by moving a paper ribbon slowly along for the wheel to press against when it rises, a self-recording morse inker is produced. the ribbon-feeding apparatus is set in motion automatically by the current, and continues to pull the ribbon along until the message is completed. the hughes type-printer covers a sheet of paper with printed characters in bold roman type. the transmitter has a keyboard, on which are marked letters, signs, and numbers; also a type-wheel, with the characters on its circumference, rotated by electricity. the receiver contains mechanisms for rotating another type-wheel synchronously--that is, in time--with the first; for shifting the wheel across the paper; for pressing the paper against the wheel; and for moving the paper when a fresh line is needed. these are too complicated to be described here in detail. by means of relays one transmitter may be made to work five hundred receivers. in london a single operator, controlling a keyboard in the central dispatching office, causes typewritten messages to spell themselves out simultaneously in machines distributed all over the metropolis. the tape machine resembles that just described in many details. the main difference is that it prints on a continuous ribbon instead of on sheets. automatic electric printers of some kind or other are to be found in the vestibules of all the principal hotels and clubs of our large cities, and in the offices of bankers, stockbrokers, and newspaper editors. in london alone over million words are printed by the receivers in a year. high-speed telegraphy. at certain seasons, or when important political events are taking place, the telegraph service would become congested with news were there not some means of transmitting messages at a much greater speed than is possible by hand signalling. fifty words a minute is about the limit speed that a good operator can maintain. by means of wheatstone's _automatic transmitter_ the rate can be increased to words per minute. paper ribbons are punched in special machines by a number of clerks with a series of holes which by their position indicate a dot or a dash. the ribbons are passed through a special transmitter, over little electric brushes, which make contact through the holes with surfaces connected to the line circuit. at the receiver end the message is printed by a morse inker. it has been found possible to send several messages simultaneously over a single line. to effect this a _distributer_ is used to put a number of transmitters at one end of the line in communication with an equal number of receivers at the other end, fed by a second distributer keeping perfect time with the first. instead of a signal coming as a whole to any one instrument it arrives in little bits, but these follow one another so closely as to be practically continuous. by working a number of automatic transmitters through a distributer, a thousand words or more per minute are easily dispatched over a single wire. the pollak virag system employs a punched ribbon, and the receiver traces out the message in alphabetical characters on a moving strip of sensitized photographic paper. a mirror attached to a vibrating diaphragm reflects light from a lamp on to the strip, which is automatically developed and fixed in chemical baths. the method of moving the mirror so as to make the rays trace out words is extremely ingenious. messages have been transmitted by this system at the rate of , words per hour. chapter vii. wireless telegraphy. the transmitting apparatus--the receiving apparatus--syntonic transmission--the advance of wireless telegraphy. in our last chapter we reviewed briefly some systems of sending telegraphic messages from one point of the earth's surface to another through a circuit consisting partly of an insulated wire and partly of the earth itself. the metallic portion of a long circuit, especially if it be a submarine cable, is costly to install, so that in quite the early days of telegraphy efforts were made to use the ether in the place of wire as one conductor. when a hammer strikes an anvil the air around is violently disturbed. this disturbance spreads through the molecules of the air in much the same way as ripples spread from the splash of a stone thrown into a pond. when the sound waves reach the ear they agitate the tympanum, or drum membrane, and we "hear a noise." the hammer is here the transmitter, the air the conductor, the ear the receiver. in wireless telegraphy we use the ether as the conductor of electrical disturbances.[ ] marconi, slaby, branly, lodge, de forest, popoff, and others have invented apparatus for causing disturbances of the requisite kind, and for detecting their presence. the main features of a wireless telegraphy outfit are shown in figs. and . the transmitter apparatus. we will first consider the transmitting outfit (fig. ). it includes a battery, dispatching key, and an induction coil having its secondary circuit terminals connected with two wires, the one leading to an earth-plate, the other carried aloft on poles or suspended from a kite. in the large station at poldhu, cornwall, for transatlantic signalling, there are special wooden towers feet high, between which the aërial wires hang. at their upper and lower ends respectively the earth and aërial wires terminate in brass balls separated by a gap. when the operator depresses the key the induction coil charges these balls and the wires attached thereto with high-tension electricity. as soon as the quantity collected exceeds the resistance of the air-gap, a discharge takes place between the balls, and the ether round the aërial wire is violently disturbed, and waves of electrical energy are propagated through it. the rapidity with which the discharges follow one another, and their travelling power, depends on the strength of the induction coil, the length of the air-gap, and the capacity of the wires.[ ] [illustration: fig. .--sketch of the transmitter of a wireless telegraphy outfit.] [illustration: fig. .--a marconi coherer.] receiving apparatus. the human body is quite insensitive to these etheric waves. we cannot feel, hear, or see them. but at the receiving station there is what may be called an "electric eye." technically it is named a _coherer_. a marconi coherer is seen in fig. . inside a small glass tube exhausted of air are two silver plugs, p p, carrying terminals, t t, projecting through the glass at both ends. a small gap separates the plugs at the centre, and this gap is partly filled with nickel-silver powder. if the terminals of the coherer are attached to those of a battery, practically no current will pass under ordinary conditions, as the particles of nickel-silver touch each other very lightly and make a "bad contact." but if the coherer is also attached to wires leading into the earth and air, and ether waves strike those wires, at every impact the particles will cohere--that is, pack tightly together--and allow battery current to pass. the property of cohesion of small conductive bodies when influenced by hertzian waves was first noticed in by professor d.e. hughes while experimenting with a telephone. [illustration: fig. .--sketch of the receiving apparatus in a wireless telegraphy outfit.] we are now in a position to examine the apparatus of which a coherer forms part (fig. ). first, we notice the aërial and earth wires, to which are attached other wires from battery a. this battery circuit passes round the relay magnet r and through two choking coils, whose function is to prevent the hertzian waves entering the battery. the relay, when energized, brings contact d against e and closes the circuit of battery b, which is much more powerful than battery a, and operates the magnet m as well as the _tapper_, which is practically an electric bell minus the gong. (the tapper circuit is indicated by the dotted lines.) we will suppose the transmitter of a distant station to be at work. the electric waves strike the aërial wire of the receiving station, and cause the coherer to cohere and pass current. the relay is closed, and both tapper and morse inker begin to work. the tapper keeps striking the coherer and shakes the particles loose after every cohesion. if this were not done the current of a would pass continuously after cohesion had once taken place. when the key of the transmitter is pressed down, the waves follow one another very quickly, and the acquired conductivity of the coherer is only momentarily destroyed by the tap of the hammer. during the impression of a dot by the morse inker, contact is made and broken repeatedly; but as the armature of the inker is heavy and slow to move it does not vibrate in time with the relay and tapper. therefore the morse instrument reproduces in dots and dashes the short and long depressions of the key at the transmitting station, while the tapper works rapidly in time with the relay. the morse inker is shown diagrammatically. while current passes through m the armature is pulled towards it, the end p, carrying an inked wheel, rises, and a mark is made on the tape w, which is moved continuously being drawn forward off reel r by the clockwork--or electrically-driven rollers r^ r^ . syntonic transmission. if a number of transmitting stations are sending out messages simultaneously, a jumble of signals would affect all the receivers round, unless some method were employed for rendering a receiver sensitive only to the waves intended to influence it. also, if distinction were impossible, even with one transmitter in action its message might go to undesired stations. there are various ways of "tuning" receivers and transmitters, but the principle underlying them all is analogous to that of mechanical vibration. if a weight is suspended from the end of a spiral spring, and given an upward blow, it bobs up and down a certain number of times per minute, every movement from start to finish having exactly the same duration as the rest. the resistance of the air and the internal friction of the spring gradually lessen the amplitude of the movements, and the weight finally comes to rest. suppose that the weight scales lbs., and that it naturally bobs twenty times a minute. if you now take a feather and give it a push every three seconds you can coax it into vigorous motion, assuming that every push catches it exactly on the rebound. the same effect would be produced more slowly if or second intervals were substituted. but if you strike it at , , or second intervals it will gradually cease to oscillate, as the effect of one blow neutralizes that of another. the same phenomenon is witnessed when two tuning-forks of equal pitch are mounted near one another, and one is struck. the other soon picks up the note. but a fork of unequal pitch would remain dumb. now, every electrical circuit has a "natural period of oscillation" in which its electric charge vibrates. it is found possible to "tune," or "syntonize," the aërial rod or wire of a receiving station with a transmitter. a vertical wire about feet in length, says professor j.a. fleming,[ ] has a natural time period of electrical oscillation of about one-millionth of a second. therefore if waves strike this wire a million times a second they will reinforce one another and influence the coherer; whereas a less or greater frequency will leave it practically unaffected. by adjusting the receiving circuit to the transmitter, or _vice versâ_, selective wireless telegraphy becomes possible. advance of wireless telegraphy. the history of wireless telegraphy may be summed up as follows:-- .--professor morse sent aërial messages across the susquehanna river. a line containing a battery and transmitter was carried on posts along one bank and "earthed" in the river at each end. on the other bank was a second wire attached to a receiver and similarly earthed. whenever contact was made and broken on the battery side, the receiver on the other was affected. distance about mile. .--james bowman lindsay transmitted messages across the tay at glencarse in a somewhat similar way. distance about / mile. .--sir william preece signalled from lavernock point, near cardiff, to steep holm, an island in the bristol channel. distance about - / miles. in all these electrical _induction_ of current was employed. .--hertzian waves discovered. .--professor a. popoff sent hertzian wave messages over a distance of miles. .--marconi signalled from the needles hotel, isle of wight, to swanage; - / miles. .--messages sent at sea for miles. , dec. .--messages transmitted from poldhu, cornwall, to hospital point, newfoundland; , miles. mr. marconi has so perfected tuning devices that his transatlantic messages do not affect receivers placed on board ships crossing the ocean, unless they are purposely tuned. atlantic liners now publish daily small newspapers containing the latest news, flashed through space from land stations. in the united states the de forest and fessenden systems are being rapidly extended to embrace the most out-of-the-way districts. every navy of importance has adopted wireless telegraphy, which, as was proved during the russo-japanese war, can be of the greatest help in directing operations. [ ] named after their first discoverer, dr. hertz of carlsruhe, "hertzian waves." [ ] for long-distance transmission powerful dynamos take the place of the induction coil and battery. [ ] "technics," vol. ii. p. . chapter viii. the telephone. the bell telephone--the edison transmitter--the granular carbon transmitter--general arrangement of a telephone circuit--double-line circuits--telephone exchanges--submarine telephony. for the purposes of everyday life the telephone is even more useful than the telegraph. telephones now connect one room of a building with another, house with house, town with town, country with country. an infinitely greater number of words pass over the telephonic circuits of the world in a year than are transmitted by telegraph operators. the telephone has become an important adjunct to the transaction of business of all sorts. its wires penetrate everywhere. without moving from his desk, the london citizen may hold easy converse with a parisian, a new yorker with a dweller in chicago. wonderful as the transmission of signals over great distances is, the transmission of human speech so clearly that individual voices may be distinguished hundreds of miles away is even more so. yet the instrument which works the miracle is essentially simple in its principles. the bell telephone. [illustration: fig. .--section of a bell telephone.] the first telephone that came into general use was that of bell, shown in fig. . in a central hole of an ebonite casing is fixed a permanent magnet, m. the casing expands at one end to accommodate a coil of insulated wire wound about one extremity of a magnet. the coil ends are attached to wires passing through small channels to terminals at the rear. a circular diaphragm, d, of very thin iron plate, clamped between the concave mouthpiece and the casing, almost touches the end of the magnet. we will suppose that two bell telephones, a and b, are connected up by wires, so that the wires and the coils form a complete circuit. words are spoken into a. the air vibrations, passing through the central hole in the cover, make the diaphragm vibrate towards and away from the magnet. the distances through which the diaphragm moves have been measured, and found not to exceed in some cases more than / , , of an inch! its movements distort the shape of the "lines of force" (see p. ) emanating from the magnet, and these, cutting through the turns of the coil, induce a current in the line circuit. as the diaphragm approaches the magnet a circuit is sent in one direction; as it leaves it, in the other. consequently speech produces rapidly alternating currents in the circuit, their duration and intensity depending on the nature of the sound. now consider telephone b. the currents passing through its coil increase or diminish the magnetism of the magnet, and cause it to attract its diaphragm with varying force. the vibration of the diaphragm disturbs the air in exact accordance with the vibrations of a's diaphragm, and speech is reproduced. the edison transmitter. the bell telephone may be used both as a transmitter and a receiver, and the permanent magnetism of the cores renders it independent of an electric battery. but currents generated by it are so minute that they cannot overcome the resistance of a long circuit; therefore a battery is now always used, and with it a special device as transmitter. if in a circuit containing a telephone and a battery there be a loose contact, and this be shaken, the varying resistance of the contact will cause electrical currents of varying force to pass through the circuit. edison introduced the first successful _microphone_ transmitter, in which a small platinum disc connected to the diaphragm pressed with varying force against a disc of carbon, each disc forming part of the circuit. vibrations of the diaphragm caused current to flow in a series of rapid pulsations. [illustration: fig. .--section of a granular carbon transmitter.] the granular carbon transmitter. in fig. we have a section of a microphone transmitter now very widely used. it was invented, in its original form, by an english clergyman named hunnings. resting in a central cavity of an ebonite seating is a carbon block, c, with a face moulded into a number of pyramidal projections, p p. the space between c and a carbon diaphragm, d, is packed with carbon granules, g g. c has direct contact with line terminal t, which screws into it; d with t^ through the brass casing, screw s, and a small plate at the back of the transmitter. voice vibrations compress g g, and allow current to pass more freely from d to c. this form of microphone is very delicate, and unequalled for long-distance transmission. [illustration: fig. .--a diagrammatic representation of a telephonic circuit.] general arrangement of a telephone circuit. in many forms of subscriber's instruments both receiver and transmitter are mounted on a single handle in such a way as to be conveniently placed for ear and mouth. for the sake of clearness the diagrammatic sketch of a complete installation (fig. ) shows them separated. the transmitters, it will be noticed, are located in battery circuits, including the primary windings p p_ of induction coils. the transmitters are in the line circuit, which includes the secondary windings s s_ of the coils. we will assume that the transmitters are, in the first instance, both hung on the hooks of the metallic switches, which their weight depresses to the position indicated by the dotted lines. the handle of the magneto-generator at the left-end station is turned, and current passes through the closed circuit:--line a, e b_ , contact , the switch ; line b, , the other switch, contact , and e b. both bells ring. both parties now lift their receivers from the switch hooks. the switches rise against contacts , , and , , respectively. both primary and both secondary circuits are now completed, while the bells are disconnected from the line wires. the pulsations set up by transmitter t in primary coil p are magnified by secondary coil s for transmission through the line circuit, and affect both receivers. the same thing happens when t_ is used. at the end of the conversation the receivers are hung on their hooks again, and the bell circuit is remade, ready for the next call. [illustration: a telephone exchange.] double-line circuits. the currents used in telephones pulsate very rapidly, but are very feeble. electric disturbances caused by the proximity of telegraph or tram wires would much interfere with them if the earth were used for the return circuit. it has been found that a complete metallic circuit (two wires) is practically free from interference, though where a number of wires are hung on the same poles, speech-sounds may be faintly induced in one circuit from another. this defect is, however, minimized by crossing the wires about among themselves, so that any one line does not pass round the corresponding insulator on every pole. telephone exchanges. in a district where a number of telephones are used the subscribers are put into connection with one another through an "exchange," to which all the wires lead. one wire of each subscriber runs to a common "earth;" the other terminates at a switchboard presided over by an operator. in an exchange used by many subscribers the terminals are distributed over a number of switchboards, each containing to terminals, and attended to by an operator, usually a girl. when a subscriber wishes to be connected to another subscriber, he either turns the handle of a magneto generator, which causes a shutter to fall and expose his number at the exchange, or simply depresses a key which works a relay at the exchange and lights a tiny electric lamp. the operator, seeing the signal, connects her telephone with the subscriber's circuit and asks the number wanted. this given, she rings up the other subscriber, and connects the two circuits by means of an insulated wire cord having a spike at each end to fit the "jack" sockets of the switchboard terminals. the two subscribers are now in communication. [illustration: fig. .--the headdress of an operator at a telephone exchange. the receiver is fastened over one ear, and the transmitter to the chest.] if a number on switchboard a calls for a number on switchboard c, the operator at a connects her subscriber by a jack cord to a trunk line running to c, where the operator similarly connects the trunk line with the number asked for, after ringing up the subscriber. the central exchange of one town is connected with that of another by one or more trunk lines, so that a subscriber may speak through an indefinite number of exchanges. so perfect is the modern telephone that the writer remembers on one occasion hearing the door-bell ring in a house more than a hundred miles away, with which he was at the moment in telephonic connection, though three exchanges were in the circuit. submarine telephony. though telegraphic messages are transmitted easily through thousands of miles of cable,[ ] submarine telephony is at present restricted to comparatively short distances. when a current passes through a cable, electricity of opposite polarity induced on the outside of the cable damps the vibration in the conductor. in the atlantic cable, strong currents of electricity are poured periodically into one end, and though much enfeebled when they reach the other they are sufficiently strong to work a very delicate "mirror galvanometer" (invented by lord kelvin), which moves a reflected ray up and down a screen, the direction of the movements indicating a dot or a dash. reversible currents are used in transmarine telegraphy. the galvanometer is affected like the coils and small magnet in wheatstone's needle instrument (p. ). telephonic currents are too feeble to penetrate many miles of cable. there is telephonic communication between england and france, and england and ireland. but transatlantic telephony is still a thing of the future. it is hoped, however, that by inserting induction coils at intervals along the cables the currents may be "stepped up" from point to point, and so get across. turning to fig. , we may suppose s to be on shore at the english end, and s_ to be the _primary_ winding of an induction coil a hundred miles away in the sea, which magnifies the enfeebled vibrations for a journey to s_ , where they are again revived; and so on, till the new world is reached. the difficulty is to devise induction coils of great power though of small size. yet science advances nowadays so fast that we may live to hear words spoken at the antipodes. [ ] in the late li hung chang sent a cablegram from china to england ( , miles), and received a reply, in _seven minutes_. chapter ix. dynamos and electric motors. a simple dynamo--continuous-current dynamos--multipolar dynamos--exciting the field magnets--alternating current dynamos--the transmission of power--the electric motor--electric lighting--the incandescent lamp--arc lamps--"series" and "parallel" arrangement of lamps--current for electric lamps--electroplating. in previous chapters we have incidentally referred to the conversion of mechanical work into electrical energy. in this we shall examine how it is done--how the silently spinning dynamo develops power, and why the motor spins when current is passed through it. we must begin by returning to our first electrical diagram (fig. ), and calling to mind the invisible "lines of force" which permeate the ether in the immediate neighbourhood of a magnet's poles, called the _magnetic field_ of the magnet. many years ago ( ) the great michael faraday discovered that if a loop of wire were moved up and down between the poles of an electro-magnet (fig. ) a current was induced in the loop, its direction depending upon that in which the loop was moved. the energy required to cut the lines of force passed in some mysterious way into the wire. why this is so we cannot say, but, taking advantage of the fact, electricians have gradually developed the enormous machines which now send vehicles spinning over metal tracks, light our streets and houses, and supply energy to innumerable factories. [illustration: fig. .] the strength of the current induced in a circuit cutting the lines of force of a magnet is called its pressure, voltage, or electro-motive force (expressed shortly e.m.f.). it may be compared with the pounds-to-the-square-inch of steam. in order to produce an e.m.f. of one volt it is calculated that , , lines of force must be cut every second. the voltage depends on three things:--( .) the _strength_ of the magnet: the stronger it is, the greater the number of lines of force coming from it. ( .) the _length_ of the conductor cutting the lines of force: the longer it is, the more lines it will cut. ( .) the _speed_ at which the conductor moves: the faster it travels, the more lines it will cut in a given time. it follows that a powerful dynamo, or mechanical producer of current, must have strong magnets and a long conductor; and the latter must be moved at a high speed across the lines of force. a simple dynamo. in fig. we have the simplest possible form of dynamo--a single turn of wire, _w x y z_, mounted on a spindle, and having one end attached to an insulated ring c, the other to an insulated ring c^ . two small brushes, b b^ , of wire gauze or carbon, rubbing continuously against these collecting rings, connect them with a wire which completes the circuit. the armature, as the revolving coil is called, is mounted between the poles of a magnet, where the lines of force are thickest. these lines are _supposed_ to stream from the n. to the s. pole. in fig. the armature has reached a position in which _y z_ and _w x_ are cutting no, or very few, lines of force, as they move practically parallel to the lines. this is called the _zero_ position. [illustration: fig. .] [illustration: fig. .] in fig. the armature, moving at right angles to the lines of force, cuts a maximum number in a given time, and the current induced in the coil is therefore now most intense. here we must stop a moment to consider how to decide in which direction the current flows. the armature is revolving in a clockwise direction, and _y z_, therefore, is moving downwards. now, suppose that you rest your _left_ hand on the n. pole of the magnet so that the arm lies in a line with the magnet. point your forefinger towards the s. pole. it will indicate the _direction of the lines of force_. bend your other three fingers downwards over the edge of the n. pole. they will indicate the _direction in which the conductor is moving_ across the magnetic field. stick out the thumb at right angles to the forefinger. it points in the direction in which the _induced_ current is moving through the nearer half of the coil. therefore lines of force, conductor, and induced current travel in planes which, like the top and two adjacent sides of a box, are at right angles to one another. while current travels from _z_ to _y_--that is, _from_ the ring c^ to _y_--it also travels from _x_ to _w_, because _w x_ rises while _y z_ descends. so that a current circulates through the coil and the exterior part of the circuit, including the lamp. after _z y_ has passed the lowest possible point of the circle it begins to ascend, _w x_ to descend. the direction of the current is therefore reversed; and as the change is repeated every half-revolution this form of dynamo is called an _alternator_ or creator of alternating currents. a well-known type of alternator is the magneto machine which sends shocks through any one who completes the external circuit by holding the brass handles connected by wires to the brushes. the faster the handle of the machine is turned the more frequent is the alternation, and the stronger the current. [illustration: fig. .] continuous-current dynamos. an alternating current is not so convenient for some purposes as a continuous current. it is therefore sometimes desirable (even necessary) to convert the alternating into a uni-directional or continuous current. how this is done is shown in figs. and . in place of the two collecting rings c c^ , we now have a single ring split longitudinally into two portions, one of which is connected to each end of the coil _w x y z_. in fig. brush b has just passed the gap on to segment c, brush b^ on to segment c^ . for half a revolution these remain respectively in contact; then, just as _y z_ begins to rise and _w x_ to descend, the brushes cross the gaps again and exchange segments, so that the current is perpetually flowing one way through the circuit. the effect of the commutator[ ] is, in fact, equivalent to transposing the brushes of the collecting rings of the alternator every time the coil reaches a zero position. figs. and give end views in section of the coil and the commutator, with the coil in the position of minimum and maximum efficiency. the arrow denotes the direction of movement; the double dotted lines the commutator end of the revolving coil. [illustration: fig. .] practical continuous-current dynamos. the electrical output of our simple dynamo would be increased if, instead of a single turn of wire, we used a coil of many turns. a further improvement would result from mounting on the shaft, inside the coil, a core or drum of iron, to entice the lines of force within reach of the revolving coil. it is evident that any lines which pass through the air outside the circle described by the coil cannot be cut, and are wasted. [illustration: fig. .] [illustration: fig. .] the core is not a solid mass of iron, but built up of a number of very thin iron discs threaded on the shaft and insulated from one another to prevent electric eddies, which would interfere with the induced current in the conductor.[ ] sometimes there are openings through the core from end to end to ventilate and cool it. [illustration: fig. .] we have already noticed that in the case of a single coil the current rises and falls in a series of pulsations. such a form of armature would be unsuitable for large dynamos, which accordingly have a number of coils wound over their drums, at equal distances round the circumference, and a commutator divided into an equal number of segments. the subject of drum winding is too complicated for brief treatment, and we must therefore be content with noticing that the coils are so connected to their respective commutator segments and to one another that they mutually assist one another. a glance at fig. will help to explain this. here we have in section a number of conductors on the right of the drum (marked with a cross to show that current is moving, as it were, into the page), connected with conductors on the left (marked with a dot to signify current coming out of the page). if the "crossed" and "dotted" conductors were respectively the "up" and "down" turns of a single coil terminating in a simple split commutator (fig. ), when the coil had been revolved through an angle of ° some of the up turns would be ascending and some descending, so that conflicting currents would arise. yet we want to utilize the whole surface of the drum; and by winding a number of coils in the manner hinted at, each coil, as it passes the zero point, top or bottom, at once generates a current in the desired direction and reinforces that in all the other turns of its own and of other coils on the same side of a line drawn vertically through the centre. there is thus practically no fluctuation in the pressure of the current generated. the action of single and multiple coil windings may be compared to that of single and multiple pumps. water is ejected by a single pump in gulps; whereas the flow from a pipe fed by several pumps arranged to deliver consecutively is much more constant. multipolar dynamos. hitherto we have considered the magnetic field produced by one bi-polar magnet only. large dynamos have four, six, eight, or more field magnets set inside a casing, from which their cores project towards the armature so as almost to touch it (fig. ). the magnet coils are wound to give n. and s. poles alternately at their armature ends round the field; and the lines of force from each n. pole stream each way to the two adjacent s. poles across the path of the armature coils. in dynamos of this kind several pairs of collecting brushes pick current off the commutator at equidistant points on its circumference. [illustration: fig. .--a holmes continuous current dynamo: a, armature; c, commutator; m, field magnets.] exciting the field magnets. until current passes through the field magnet coils, no magnetic field can be created. how are the coils supplied with current? a dynamo, starting for the first time, is excited by a current from an outside source; but when it has once begun to generate current it feeds its magnets itself, and ever afterwards will be self-exciting,[ ] owing to the residual magnetism left in the magnet cores. [illustration: fig. .--partly finished commutator.] look carefully at figs. and . in the first of these you will observe that part of the wire forming the external circuit is wound round the arms of the field magnet. this is called a _series_ winding. in this case _all_ the current generated helps to excite the dynamo. at the start the residual magnetism of the magnet cores gives a weak field. the armature coils cut this and pass a current through the circuit. the magnets are further excited, and the field becomes stronger; and so on till the dynamo is developing full power. series winding is used where the current in the external circuit is required to be very constant. [illustration: fig. .--the brushes of a holmes dynamo.] fig. shows another method of winding--the _shunt_. most of the current generated passes through the external circuit , ; but a part is switched through a separate winding for the magnets, denoted by the fine wire , . here the strength of the magnetism does not vary directly with the current, as only a small part of the current serves the magnets. the shunt winding is therefore used where the voltage (or pressure) must be constant. [illustration: fig. .--sketch showing a "series" winding.] [illustration: fig. .--"shunt" winding.] a third method is a combination of the two already named. a winding of fine wire passes from brush to brush round the magnets; and there is also a series winding as in fig. . this compound method is adapted more especially for electric traction. alternating dynamos. these have their field magnets excited by a separate continuous current dynamo of small size. the field magnets usually revolve inside a fixed armature (the reverse of the arrangement in a direct-current generator); or there may be a fixed central armature and field magnets revolving outside it. this latter arrangement is found in the great power stations at niagara falls, where the enormous field-rings are mounted on the top ends of vertical shafts, driven by water-turbines at the bottom of pits feet deep, down which water is led to the turbines through great pipes, or penstocks. the weight of each shaft and the field-ring attached totals about thirty-five tons. this mass revolves times a minute, and , horse power is constantly developed by the dynamo. similar dynamos of , horse power each have been installed on the canadian side of the falls. [illustration: fig. .] transmission of power. alternating current is used where power has to be transmitted for long distances, because such a current can be intensified, or stepped up, by a transformer somewhat similar in principle to a ruhmkorff coil _minus_ a contact-breaker (see p. ). a typical example of transformation is seen in fig. . alternating current of , volts pressure is produced in the generating station and sent through conductors to a distant station, where a transformer, b, reduces the pressure to volts to drive an alternating motor, c, which in turn operates a direct current dynamo, d. this dynamo has its + terminal connected with the insulated or "live" rail of an electric railway, and its - terminal with the wheel rails, which are metallically united at the joints to act as a "return." on its way from the live rail to the return the current passes through the motors. in the case of trams the conductor is either a cable carried overhead on standards, from which it passes to the motor through a trolley arm, or a rail laid underground in a conduit between the rails. in the top of the conduit is a slit through which an arm carrying a contact shoe on the end projects from the car. the shoe rubs continuously on the live rail as the car moves. to return for a moment to the question of transformation of current. "why," it may be asked, "should we not send low-pressure _direct_ current to a distant station straight from the dynamo, instead of altering its nature and pressure? or, at any rate, why not use high-pressure direct current, and transform _that_?" the answer is, that to transmit a large amount of electrical energy at low pressure (or voltage) would necessitate large volume (or _amperage_) and a big and expensive copper conductor to carry it. high-pressure direct current is not easily generated, since the sparking at the collecting brushes as they pass over the commutator segments gives trouble. so engineers prefer high-pressure alternating current, which is easily produced, and can be sent through a small and inexpensive conductor with little loss. also its voltage can be transformed by apparatus having no revolving parts. the electric motor. anybody who understands the dynamo will also be able to understand the electric motor, which is merely a reversed dynamo. imagine in fig. a dynamo taking the place of the lamp and passing current through the brushes and commutator into the coil _w x y z_. now, any coil through which current passes becomes a magnet with n. and s. poles at either end. (in fig. we will assume that the n. pole is below and the s. pole above the coil.) the coil poles therefore try to seek the contrary poles of the permanent magnet, and the coil revolves until its s. pole faces the n. of the magnet, and _vice versâ_. the lines of force of the coil and the magnet are now parallel. but the momentum of revolution carries the coil on, and suddenly the commutator reverses its polarity, and a further half-revolution takes place. then comes a further reversal, and so on _ad infinitum_. the rotation of the motor is therefore merely a question of repulsion and attraction of like and unlike poles. an ordinary compass needle may be converted into a tiny motor by presenting the n. and s. poles of a magnet to its s. and n. poles alternately every half-revolution. in construction and winding a motor is practically the same as a dynamo. in fact, either machine can perform either function, though perhaps not equally well adapted for both. motors may be run with direct or alternating current, according to their construction. on electric cars the motor is generally suspended from the wheel truck, and a small pinion on the armature shaft gears with a large pinion on a wheel axle. one great advantage of electric traction is that every vehicle of a train can carry its own motor, so that the whole weight of the train may be used to get a grip on the rails when starting. where a single steam locomotive is used, the adhesion of its driving-wheels only is available for overcoming the inertia of the load; and the whole strain of starting is thrown on to the foremost couplings. other advantages may be summed up as follows:--( ) ease of starting and rapid acceleration; ( ) absence of waste of energy (in the shape of burning fuel) when the vehicles are at rest; ( ) absence of smoke and smell. electric lighting. dynamos are used to generate current for two main purposes--( ) to supply power to motors of all kinds; ( ) to light our houses, factories, and streets. in private houses and theatres incandescent lamps are generally used; in the open air, in shops, and in larger buildings, such as railway stations, the arc lamp is more often found. incandescent lamp. if you take a piece of very fine iron wire and lay it across the terminals of an accumulator, it becomes white hot and melts, owing to the heat generated by its resistance to the current. a piece of fine platinum wire would become white hot without melting, and would give out an intense light. here we have the principle of the glow or incandescent lamp--namely, the interposition in an electric circuit of a conductor which at once offers a high resistance to the current, but is not destroyed by the resulting heat. in fig. is shown a fan propelling liquid constantly through a pipe. let us assume that the liquid is one which develops great friction on the inside of the pipe. at the contraction, where the speed of travel is much greater than elsewhere in the circuit, most heat will be produced. [illustration: fig. .--diagram to show circulation of water through a pipe.] in quite the early days of the glow-lamp platinum wire was found to be unreliable as regards melting, and filaments of carbon are now used. to prevent the wasting away of the carbon by combination with oxygen the filament is enclosed in a glass bulb from which practically all air has been sucked by a mercury pump before sealing. [illustration: fig. .--the electrical counterpart of fig. . the filament takes the place of the contraction in the pipe.] the manufacture of glow-lamps is now an important industry. one brand of lamp[ ] is made as follows:--first, cotton-wool is dissolved in chloride of zinc, and forms a treacly solution, which is squirted through a fine nozzle into a settling solution which hardens it and makes it coil up like a very fine violin string. after being washed and dried, it is wound on a plumbago rod and baked in a furnace until only the carbon element remains. this is the filament in the rough. it is next removed from the rod and tipped with two short pieces of fine platinum wire. to make the junction electrically perfect the filament is plunged in benzine and heated to whiteness by the passage of a strong current, which deposits the carbon of the benzine on the joints. the filament is now placed under the glass receiver of an air-pump, the air is exhausted, hydro-carbon vapour is introduced, and the filament has a current passed through it to make it white hot. carbon from the vapour is deposited all over the filament until the required electrical resistance is attained. the filament is now ready for enclosure in the bulb. when the bulb has been exhausted and sealed, the lamp is tested, and, if passed, goes to the finishing department, where the two platinum wires (projecting through the glass) are soldered to a couple of brass plates, which make contact with two terminals in a lamp socket. finally, brass caps are affixed with a special water-tight and hard cement. arc lamps. in _arc_ lighting, instead of a contraction at a point in the circuit, there is an actual break of very small extent. suppose that to the ends of the wires leading from a dynamo's terminals we attach two carbon rods, and touch the end of the rods together. the tips become white hot, and if they are separated slightly, atoms of incandescent carbon leap from the positive to the negative rod in a continuous and intensely luminous stream, which is called an _arc_ because the path of the particles is curved. no arc would be formed unless the carbons were first touched to start incandescence. if they are separated too far for the strength of the current to bridge the gap the light will flicker or go out. the arc lamp is therefore provided with a mechanism which, when the current is cut off, causes the carbons to fall together, gradually separates them when it is turned on, and keeps them apart. the principle employed is the effort of a coil through which a current passes to draw an iron rod into its centre. some of the current feeding the lamp is shunted through a coil, into which projects one end of an iron bar connected with one carbon point. a spring normally presses the points together when no current flows. as soon as current circulates through the coil the bar is drawn upwards against the spring. series and parallel arrangement of lamps. when current passes from one lamp to another, as in fig. , the lamps are said to be in _series_. should one lamp fail, all in the circuit would go out. but where arc lamps are thus arranged a special mechanism on each lamp "short-circuits" it in case of failure, so that current may pass uninterruptedly to the next. [illustration: fig. .--incandescent lamps connected in "series."] fig. shows a number of lamps set _in parallel_. one terminal of each is attached to the positive conductor, the other to the negative conductor. each lamp therefore forms an independent bridge, and does not affect the efficiency of the rest. _parallel series_ signifies a combination of the two systems, and would be illustrated if, in fig. , two or more lamps were connected in series groups from one conductor to the other. this arrangement is often used in arc lighting. [illustration: fig. .--incandescent lamps connected in "parallel."] current for electric lamps. this may be either direct or alternating. the former is commonly used for arc lamps, the latter for incandescent, as it is easily stepped-down from the high-pressure mains for use in a house. glow-lamps usually take current of or volts pressure. in arc lamps fed with direct current the tip of the positive carbon has a bowl-shaped depression worn in it, while the negative tip is pointed. most of the illumination comes from the inner surface of the bowl, and the positive carbon is therefore placed uppermost to throw the light downwards. an alternating current, of course, affects both carbons in the same manner, and there is no bowl. the carbons need frequent renewal. a powerful lamp uses about feet of rod in , hours if the arc is exposed to the air. some lamps have partly enclosed arcs--that is, are surrounded by globes perforated by a single small hole, which renders combustion very slow, though preventing a vacuum. electroplating. electroplating is the art of coating metals with metals by means of electricity. silver, copper, and nickel are the metals most generally deposited. the article to be coated is suspended in a chemical solution of the metal to be deposited. fig. shows a very simple plating outfit. a is a battery; b a vessel containing, say, an acidulated solution of sulphate of copper. a spoon, s, hanging in this from a glass rod, r, is connected with the zinc or negative element, z, of the battery, and a plate of copper, p, with the positive element, c. current flows in the direction shown by the arrows, from z to c, c to p, p to s, s to z. the copper deposited from the solution on the spoon is replaced by gradual dissolution of the plate, so that the latter serves a double purpose. [illustration: fig. .--an electroplating outfit.] in silver plating, p is of silver, and the solution one of cyanide of potassium and silver salts. where nickel or silver has to be deposited on iron, the article is often given a preliminary coating of copper, as iron does not make a good junction with either of the first two metals, but has an affinity for copper. [ ] from the latin _commuto_, "i exchange." [ ] only the "drum" type of armature is treated here. [ ] this refers to continuous-current dynamos only. [ ] the robertson. chapter x. railway brakes. the vacuum automatic brake--the westinghouse air-brake. in the early days of the railway, the pulling up of a train necessitated the shutting off of steam while the stopping-place was still a great distance away. the train gradually lost its velocity, the process being hastened to a comparatively small degree by the screw-down brakes on the engine and guard's van. the goods train of to-day in many cases still observes this practice, long obsolete in passenger traffic. an advance was made when a chain, running along the entire length of the train, was arranged so as to pull on subsidiary chains branching off under each carriage and operating levers connected with brake blocks pressing on every pair of wheels. the guard strained the main chain by means of a wheel gear in his van. this system was, however, radically defective, since, if any one branch chain was shorter than the rest, it alone would get the strain. furthermore, it is obvious that the snapping of the main chain would render the whole arrangement powerless. accordingly, brakes operated by steam were tried. under every carriage was placed a cylinder, in connection with a main steam-pipe running under the train. when the engineer wished to apply the brakes, he turned high-pressure steam into the train pipe, and the steam, passing into the brake cylinders, drove out in each a piston operating the brake gear. unfortunately, the steam, during its passage along the pipe, was condensed, and in cold weather failed to reach the rear carriages. water formed in the pipes, and this was liable to freeze. if the train parted accidentally, the apparatus of course broke down. hydraulic brakes have been tried; but these are open to several objections; and railway engineers now make use of air-pressure as the most suitable form of power. whatever air system be adopted, experience has shown that three features are essential:--( .) the brakes must be kept "off" artificially. ( .) in case of the train parting accidentally, the brakes must be applied automatically, and quickly bring all the vehicles of the train to a standstill. ( .) it must be possible to apply the brakes with greater or less force, according to the needs of the case. at the present day one or other of two systems is used on practically all automatically-braked cars and coaches. these are known as--( ) the _vacuum automatic_, using the pressure of the atmosphere on a piston from the other side of which air has been mechanically exhausted; and ( ) the _westinghouse automatic_, using compressed air. the action of these brakes will now be explained as simply as possible. the vacuum automatic brake. under each carriage is a vacuum chamber (fig. ) riding on trunnions, e e, so that it may swing a little when the brakes are applied. inside the chamber is a cylinder, the piston of which is rendered air-tight by a rubber ring rolling between it and the cylinder walls. the piston rod works through an air-tight stuffing-box in the bottom of the casing, and when it rises operates the brake rods. it is obvious that if air is exhausted from both sides of the piston at once, the piston will sink by reason of its own weight and that of its attachments. if air is now admitted below the piston, the latter will be pushed upwards with a maximum pressure of lbs. to the square inch. the ball-valve ensures that while air can be sucked from _both_ sides of the piston, it can be admitted to the lower side only. [illustration: fig. .--vacuum brake "off."] [illustration: fig. .--vacuum brake "on."] let us imagine that a train has been standing in a siding, and that air has gradually filled the vacuum chamber by leakage. the engine is coupled on, and the driver at once turns on the steam ejector,[ ] which sucks all the air out of the pipes and chambers throughout the train. the air is sucked directly from the under side of the piston through pipe d; and from the space a a and the cylinder (open at the top) through the channel c, lifting the ball, which, as soon as exhaustion is complete, or when the pressure on both sides of the piston is equal, falls back on its seat. on air being admitted to the train pipe, it rushes through d and into the space b (fig. ) below the piston, but is unable to pass the ball, so that a strong upward pressure is exerted on the piston, and the brakes go on. to throw them off, the space below the piston must be exhausted. this is to be noted: if there is a leak, as in the case of the train parting, _the brakes go on at once_, since the vacuum below the piston is automatically broken. [illustration: fig. .--guard's valve for applying the vacuum brake.] for ordinary stops the vacuum is only partially broken--that is, an air-pressure of but from to lbs. per square inch is admitted. for emergency stops full atmospheric pressure is used. in this case it is advisable that air should enter at _both_ ends of the train; so in the guard's van there is installed an ingenious automatic valve, which can at any time be opened by the guard pressing down a lever, but which opens of itself when the train-pipe vacuum is rapidly destroyed. fig. shows this device in section. seated on the top of an upright pipe is a valve, _a_, connected by a bolt, b, to an elastic diaphragm, c, sealing the bottom of the chamber d. the bolt b has a very small hole bored through it from end to end. when the vacuum is broken slowly, the pressure falls in d as fast as in the pipe; but a sudden inrush of air causes the valve a to be pulled off its seat by the diaphragm c, as the vacuum in d has not been broken to any appreciable extent. air then rushes into the train pipe through the valve. it is thus evident that the driver controls this valve as effectively as if it were on the engine. these "emergency" valves are sometimes fitted to every vehicle of a train. when a carriage is slipped, taps on each side of the coupling joint of the train pipe are turned off by the guard in the "slip;" and when he wishes to stop he merely depresses the lever e, gradually opening the valve. under the van is an auxiliary vacuum chamber, from which the air is exhausted by the train pipe. if the guard, after the slip has parted from the train, finds that he has applied his brakes too hard, he can put this chamber into communication with the brake cylinder, and restore the vacuum sufficiently to pull the brakes off again. when a train has come to rest, the brakes must be sucked off by the ejector. until this has been done the train cannot be moved, so that it is impossible for it to leave the station unprepared to make a sudden stop if necessary. the westinghouse air-brake. this system is somewhat more complicated than the vacuum, though equally reliable and powerful. owing to the complexity of certain parts, such as the steam air-pump and the triple-valve, it is impossible to explain the system in detail; we therefore have recourse to simple diagrammatic sketches, which will help to make clear the general principles employed. the air-brake, as first evolved by mr. george westinghouse, was a very simple affair--an air-pump and reservoir on the engine; a long pipe running along the train; and a cylinder under every vehicle to work the brakes. to stop the train, the high-pressure air collected in the reservoir was turned into the train pipe to force out the pistons in the coach cylinders, connected to it by short branch pipes. one defect of this "straight" system was that the brakes at the rear of a long train did not come into action until a considerable time after the driver turned on the air; and since, when danger is imminent, a very few seconds are of great importance, this slowness of operation was a serious fault. also, it was found that the brakes on coaches near the engine went on long before those more distant, so that during a quick stop there was a danger of the forward coaches being bumped by those behind. it goes without saying that any coaches which might break loose were uncontrollable. mr. westinghouse therefore patented his _automatic_ brake, now so largely used all over the world. the brake ensures practically instantaneous and simultaneous action on all the vehicles of _a train of any length_. [illustration: fig. .--diagrammatic sketch of the details of the westinghouse air-brake. brake "off."] the principle of the brake will be gathered from figs. and . p is a steam-driven air-pump on the engine, which compresses air into a reservoir, a, situated below the engine or tender, and maintains a pressure of from to lbs. per square inch. a three-way cock, c, puts the train pipe into communication with a or the open air at the wish of the driver. under each coach is a triple-valve, t, an auxiliary reservoir, b, and a brake cylinder, d. the triple-valve is the most noteworthy feature of the whole system. the reader must remember that the valve shown in the section is _only diagrammatic_. now for the operation of the brake. when the engine is coupled to the train, the compressed air in the main reservoir is turned into the train pipe, from which it passes through the triple-valve into the auxiliary reservoir, and fills it till it has a pressure of, say, lbs. per square inch. until the brakes are required, the pressure in the train pipe must be maintained. if accidentally, or purposely (by turning the cock c to the position shown in fig. ), the train-pipe pressure is reduced, the triple-valve at once shifts, putting b in connection with the brake cylinder d, and cutting off the connection between d and the air, and the brakes go on. to get them off, the pressure in the train pipe must be made equal to that in b, when the valve will assume its original position, allowing the air in d to escape. the force with which the brake is applied depends upon the reduction of pressure in the train pipe. a slight reduction would admit air very slowly from b to d, whereas a full escape from the train pipe would open the valve to its utmost. we have not represented the means whereby the valve is rendered sensitive to these changes, for the reason given above. [illustration: fig. .--brake "on."] the latest form of triple-valve includes a device which, when air is rapidly discharged from the train pipe, as in an emergency application of the brake, opens a port through which compressed air is also admitted from the train pipe _directly_ into d. it will easily be understood that a double advantage is hereby gained--first, in utilizing a considerable portion of the air in the train pipe to increase the available brake force in cases of emergency; and, secondly, in producing a quick reduction of pressure in the whole length of the pipe, which accelerates the action of the brakes with extraordinary rapidity. it may be added that this secondary communication is kept open only until the pressure in d is equal to that in the train pipe. then it is cut off, to prevent a return of air from b to the pipe. an interesting detail of the system is the automatic regulation of air-pressure in the main reservoir by the air-pump governor (fig. ). the governor is attached to the steam-pipe leading from the locomotive boiler to the air-pump. steam from the boiler, entering at f, flows through valve and passes by d into the pump, which is thus brought into operation, and continues to work until the pressure in the main reservoir, acting on the under side of the diaphragm , exceeds the tension to which the regulating spring is set. any excess of pressure forces the diaphragm upwards, lifting valve , and allowing compressed air from the main reservoir to flow into the chamber c. the air-pressure forces piston downwards and closes steam-valve , thus cutting off the supply of steam to the pump. as soon as the pressure in the reservoir is reduced (by leakage or use) below the normal, spring returns diaphragm to the position shown in fig. , and pin-valve closes. the compressed air previously admitted to the chamber c escapes through the small port _a_ to the atmosphere. the steam, acting on the lower surface of valve , lifts it and its piston to the position shown, and again flows to the pump, which works until the required air-pressure is again obtained in the reservoir. [illustration: fig. .--air-pump of westinghouse brake.] [ ] this resembles the upper part of the rudimentary water injector shown in fig. . the reader need only imagine pipe b to be connected with the train pipe. a rush of steam through pipe a creates a partial vacuum in the cone e, causing air from the train pipe to rush into it and be expelled by the steam blast. chapter xi. railway signalling. the block system--position of signals--interlocking the signals--locking gear--points--points and signals in combination--working the block system--series of signalling operations--single line signals--the train staff--train staff and ticket--electric train staff system--interlocking--signalling operations--power signalling--pneumatic signalling--automatic signalling. under certain conditions--namely, at sharp curves or in darkness--the most powerful brakes might not avail to prevent a train running into the rear of another, if trains were allowed to follow each other closely over the line. it is therefore necessary to introduce an effective system of keeping trains running in the same direction a sufficient distance apart, and this is done by giving visible and easily understood orders to the driver while a train is in motion. in the early days of the railway it was customary to allow a time interval between the passings of trains, a train not being permitted to leave a station until at least five minutes after the start of a preceding train. this method did not, of course, prevent collisions, as the first train sometimes broke down soon after leaving the station; and in the absence of effective brakes, its successor ran into it. the advent of the electric telegraph, which put stations in rapid communication with one another, proved of the utmost value to the safe working of railways. the block system. time limits were abolished and distance limits substituted. a line was divided into _blocks_, or lengths, and two trains going in the same direction were never allowed on any one block at the same time. the signal-posts carrying the movable arms, or semaphores, by means of which the signalman communicates with the engine-driver, are well known to us. they are usually placed on the left-hand side of the line of rails to which they apply, with their arms pointing away from the rails. the side of the arms which faces the direction from which a train approaches has a white stripe painted on a red background, the other side has a black stripe on a white background. the distant and other signal arms vary slightly in shape (fig. ). a distant signal has a forked end and a v-shaped stripe; the home and starting signals are square-ended, with straight stripes. when the arm stands horizontally, the signal is "on," or at "danger"; when dropped, it is "off," and indicates "all right; proceed." at the end nearest the post it carries a spectacle frame glazed with panes of red and green glass. when the arm is at danger, the red pane is opposite a lamp attached to the signal post; when the arm drops, the green pane rises to that position--so that a driver is kept as fully informed at night as during the day, provided the lamp remains alight. [illustration: fig. .--distant and home signals.] position of signals. on double lines each set of rails has its own separate signals, and drivers travelling on the "up" line take no notice of signals meant for the "down" line. each signal-box usually controls three signals on each set of rails--the distant, the home, and the starting. their respective positions will be gathered from fig. , which shows a station on a double line. between the distant and the home an interval is allowed of yards on the level, , yards on a falling gradient, and yards on a rising gradient. the home stands near the approach end of the station, and the starting at the departure end of the platform. the last is sometimes reinforced by an "advance starting" signal some distance farther on. it should be noted that the distant is only a _caution_ signal, whereas both home and starting are _stop_ signals. this means that when the driver sees the distant "on," he does not stop his train, but slackens speed, and prepares to stop at the home signal. he must, however, on no account pass either home or starting if they are at danger. in short, the distant merely warns the driver of what he may expect at the home. to prevent damage if a driver should overrun the home, it has been laid down that no train shall be allowed to pass the starting signal of one box unless the line is clear to a point at least a quarter of a mile beyond the home of the next box. that point is called the _standard clearing point_. technically described, a _block_ is a length of line between the last stop signal worked from one signal-box and the first stop signal worked from the next signal-box in advance. [illustration: fig. .--showing position of signals. those at the top are "off."] interlocking signals. a signalman cannot lower or restore his signals to their normal positions in any order he likes. he is compelled to lower them as follows:--starting and home; _then_ distant. and restore them--distant; _then_ starting and home. if a signalman were quite independent, he might, after the passage of a train, restore the home or starting, but forget all about the distant, so that the next train, which he wants to stop, would dash past the distant without warning and have to pull up suddenly when the home came in sight. but by a mechanical arrangement he is prevented from restoring the home or starting until the distant is at danger; and, _vice versâ_, he cannot lower the last until the other two are off. this mechanism is called _locking gear_. looking gear. there are many different types of locking gear in use. it is impossible to describe them all, or even to give particulars of an elaborate locking-frame of any one type. but if we confine ourselves to the simplest combination of a stud-locking apparatus, such as is used in small boxes on the great western railway, the reader will get an insight into the general principles of these safety devices, as the same principles underlie them all. [illustration: fig. .--a signal lever and its connections. to move the lever, c is pressed towards b raising the catch-rod from its nick in the rack, g g g, guides; r r, anti-friction rollers; s, sockets for catch-rod to work in.] the levers in the particular type of locking gear which we are considering have each a tailpiece or "tappet arm" attached to it, which moves backwards and forwards with the lever (fig. ). running at right angles to this tappet, and close to it, either under or above, are the lock bars, or stud bars. refer now to fig. , which shows the ends of the three tappet arms, d, h, and s, crossed by a bar, b, from which project these studs. the levers are all forward and the signals all "on." if the signalman tried to pull the lever attached to d down the page, as it were, he would fail to move it on account of the stud _a_, which engages with a notch in d. before this stud can be got free of the notch the tappets h and s must be pulled over, so as to bring their notches in line with studs _b_ and _c_ (fig. ). the signalman can now move d, since the notch easily pushes the stud _a_ to the left (fig. ). the signals must be restored to danger. as h and s are back-locked by d--that is, prevented by d from being put back into their normal positions--d must be moved first. the interlocking of the three signals described is merely repeated in the interlocking of a large number of signals. [illustration: fig. .] [illustration: fig. .] on entering a signal-box a visitor will notice that the levers have different colours:--_green_, signifying distant signals; _red_, signifying home and starting signals; _blue_, signifying facing points; _black_, signifying trailing points; _white_, signifying spare levers. these different colours help the signalman to pick out the right levers easily. to the front of each lever is attached a small brass tablet bearing certain numbers; one in large figures on the top, then a line, and other numbers in small figures beneath. the large number is that of the lever itself; the others, called _leads_, refer to levers which must be pulled before that particular lever can be released. [illustration: fig. .] [illustration: fig. .--model signal equipment in a signalling school. (by permission of the "g.w.r. magazine").] points. mention was made, in connection with the lever, of _points_. before going further we will glance at the action of these devices for enabling a train to run from one set of rails to another. figs. and show the points at a simple junction. it will be noticed that the rails of the line to the left of the points are continued as the outer rails of the main and branch lines. the inner rails come to a sharp v-point, and to the left of this are the two short rails which, by means of shifting portions, decide the direction of a train's travel. in fig. the main line is open; in fig. , the branch. the shifting parts are kept properly spaced by cross bars (or tie-rods), a a. [illustration: fig. .--points open to main line.] [illustration: fig. .--points open to branch line.] it might be thought that the wheels would bump badly when they reach the point b, where there is a gap. this is prevented, however, by the bent ends e e (fig. ), on which the tread of the wheel rests until it has reached some distance along the point of v. the safety rails s r keep the outer wheel up against its rail until the v has been passed. points and signals in combination. let us suppose that a train is approaching the junction shown in figs. and from the left. it is not enough that the driver should know that the tracks are clear. he must also be assured that the track, main or branch, as the case may be, along which he has to go, is open; and on the other hand, if he were approaching from the right, he would want to be certain that no train on the other line was converging on his. danger is avoided and assurance given by interlocking the points and signals. to the left of the junction the home and distant signals are doubled, there being two semaphore arms on each post. these are interlocked with the points in such a manner that the signals referring to either line can be pulled off only when the points are set to open the way to that line. moreover, before any shifting of points can be made, the signals behind must be put to danger. the convergence of trains is prevented by interlocking, which renders it impossible to have both sets of distant and home signals at "all right" simultaneously. working of block system. we may now pass to the working of the block system of signalling trains from station to station on one line of a double track. each signal-box (except, of course, those at termini) has electric communication with the next box in both directions. the instruments used vary on different systems, but the principle is the same; so we will concentrate our attention on those most commonly employed on the great western railway. they are:--( .) two tapper-bell instruments, connected with similar instruments in the adjacent boxes on both sides. each of these rings one beat in the corresponding box every time its key is depressed. ( .) two spagnoletti disc instruments--one, having two keys, communicating with the box in the rear; and the other, in connection with the forward box, having no keys. their respective functions are to give signals and receive them. in the centre of the face of each is a square opening, behind which moves a disc carrying two "flags"--"train on line" in white letters on red ground, and "line clear" in black letters on a white ground. the keyed instrument has a red and a white key. when the red key is depressed, "train on line" appears at the opening; also in that of a keyless disc at the adjacent signal-box. a depression of the white key similarly gives "line clear." a piece of wire with the ends turned over and passed through two eyes slides over the keys, and can be made to hold either down. in addition to these, telephonic and telegraphic instruments are provided to enable the signalmen to converse. series of signalling operations. [illustration: fig. .--the signaling instruments in three adjacent cabins. the featherless arrows show the connection of the instruments.] we may now watch the doings of signalmen in four successive boxes, a, b, c, and d, during the passage of an express train. signalman a calls signalman b's attention by one beat on the tapper-bell. b answers by repeating it to show that he is attending. a asks, "is line clear for passenger express?"--four beats on the bell. b, seeing that the line is clear to his clearing point, sends back four beats, and pins down the white key of his instrument. "line clear" appears on the opening, and also at that of a's keyless disc. a lowers starting signal. train moves off. a gives two beats on the tapper = "train entering section." b pins indicator at "train on line," which also appears on a's instrument. a places signals at danger. b asks c, "is line clear?" c repeats the bell code, and pins indicator at "line clear," shown on b's keyless disc also. b lowers all signals. train passes. b signals to c, "train entering section." b signals to a, "train out of section," and releases indicator, which returns to normal position with half of each flag showing at the window. b signals to c, "train on line," and sets all his signals to danger. c pins indicator to "train on line." c asks, "is line clear?" but there is a train at station d, and signalman d therefore gives no reply, which is equivalent to a negative. the driver, on approaching c's distant, sees it at danger, and slows down, stopping at the home. c lowers home, and allows train to proceed to his starting signal. d, when the line is clear to his clearing point, signals "line clear," and pins indicator at "line clear." c lowers starting signals, and train proceeds. c signals to d, "train entering section," and d pins indicator at "train on line." c signals to b, "train out of section," sets indicator at normal, and puts signals at danger. and so the process is repeated from station to station. where, however, sections are short, the signalman is advised one section ahead of the approach of a train by an additional signal signifying, "fast train approaching." the block indicator reminds the signalman of the whereabouts of the train. unless his keyless indicator is at normal, he may not ask, "is line clear?" and until he signals back "line clear" to the box behind, a train is not allowed to enter his section. in this way a section of line with a full complement of signals is always interposed between any two trains. the working of single lines. we have dealt with the signalling arrangements pertaining to double lines of railway, showing that a system of signals is necessary to prevent a train running into the back of its predecessor. where trains in both directions pass over a single line, not only has this element of danger to be dealt with, but also the possibility of a train being allowed to enter a section of line from each end _at the same time_. this is effected in several ways, the essence of each being that the engine-driver shall have in his possession _visible_ evidence of the permission accorded him by the signalman to enter a section of single line. a single train staff. the simplest form of working is to allocate to the length of line a "train staff"--a piece of wood about inches long, bearing the names of the stations at either end. this is adopted where only one engine is used for working a section, such as a short branch line. in a case like this there is obviously no danger of two trains meeting, and the train staff is merely the authority to the driver to start a journey. no telegraphic communication is necessary with such a system, and signals are placed only at the ends of the line. train staff and ticket. on long lengths of single line where more than one train has to be considered, the line is divided into blocks in the way already described for double lines, and a staff is assigned to each, the staffs for the various blocks differing from each other in shape and colour. the usual signals are provided at each station, and block telegraph instruments are employed, the only difference being that one disc, of the key pattern, is used for trains in both directions. on such a line it is, of course, possible that two or more trains may require to follow each other without any travelling intermediately in the opposite direction. this would be impossible if the staff passed uniformly to and fro in the block section; but it is arranged by the introduction of a train staff _ticket_ used in conjunction with the staff. no train is permitted to leave a staff station unless the staff for the section of line to be traversed is at the station; and the driver has the strictest possible instructions that he must _see_ the staff. if a second train is required to follow, the staff is _shown_ to the driver, and a train staff ticket handed him as his authority to proceed. if, however, the next train over the section will enter from the opposite end, the staff is _handed_ to the driver. to render this system as safe as possible, train staff tickets are of the same colour and shape as the staff for the section to which they apply, and are kept in a special box at the stations, the key being attached to the staff and the lock so arranged that the key cannot be withdrawn unless the box has been locked. electric train staff and tablet systems. these systems of working are developments of the last mentioned, by which are secured greater safety and ease in working the line. on some sections of single line circumstances often necessitate the running of several trains in one direction without a return train. for such cases the train staff ticket was introduced; but even on the best regulated lines it is not always possible to secure that the staff shall be at the station where it is required at the right time, and cases have arisen where, no train being available at the station where the staff was, it had to be taken to the other station by a man on foot, causing much delay to traffic. the electric train staff and tablet systems overcome this difficulty. both work on much the same principle, and we will therefore describe the former. [illustration: fig. .--an electric train staff holder: s s, staffs in the slot of the instrument. leaning against the side of the cabin is a staff showing the key k at the end for unlocking a siding points between two stations. the engine driver cannot remove the staff until the points have been locked again.] at each end of a block section a train staff instrument (fig. ) is provided. in the base of these instruments are a number of train staffs, any one of which would be accepted by an engine-driver as permission to travel over the single line. the instruments are electrically connected, the mechanism securing that a staff can be withdrawn only by the co-operation of the signalman at each end of the section; that, when _all_ the staffs are in the instruments, a staff may be withdrawn at _either_ end; that, when a staff has been withdrawn, another cannot be obtained until the one out has been restored to one or other of the instruments. the safety of such a system is obvious, as also the assistance to the working by having a staff available for a train no matter from which end it is to enter the section. the mechanism of the instruments is quite simple. a double-poled electro-magnet is energized by the depression of a key by the signalman at the further end of the block into which the train is to run, and by the turning of a handle by the signalman who requires to withdraw a staff. the magnet, being energized, is able to lift a mechanical lock, and permits the withdrawal of a staff. in its passage through the instrument the staff revolves a number of iron discs, which in turn raise or lower a switch controlling the electrical connections. this causes the electric currents actuating the electro-magnet to oppose each other, the magnetism to cease, and the lock to fall back, preventing another staff being withdrawn. it will naturally be asked, "how is the electrical system restored?" we have said that there were a number of staffs in each instrument--in other words, a given number of staffs, usually twenty, is assigned to the section. assume that there are ten in each instrument, and that the switch in each is in its lower position. now withdraw a staff, and one instrument has an odd, the other an even, number of staffs, and similarly one switch is raised while the other remains lowered, therefore the electrical circuit is "out of phase"--that is, the currents in the magnets of each staff instrument are opposed to one another, and cannot release the lock. the staff travels through the section and is placed in the instrument at the other end, bringing the number of staffs to eleven--an odd number, and, what is more important, _raising_ the switch. both switches are now raised, consequently the electric currents will support each other, so that a staff may be withdrawn. briefly, then, when there is an odd number of staffs in one instrument and an even number in the other, as when a staff is in use, the signalmen are unable to obtain a staff, and consequently cannot give authority for a train to enter the section; but when there is either an odd or an even number of staffs in each instrument a staff may be withdrawn at either end on the co-operation of the signalmen. we may add that, where two instruments are in the same signal-box, one for working to the box in advance, the other to the rear, it is arranged that the staffs pertaining to one section shall not fit the instrument for the other, and must be of different colours. this prevents the driver accidentally accepting a staff belonging to one section as authority to travel over the other. interlocking. the remarks made on the interlocking of points and signals on double lines apply also to the working of single lines, with the addition that not only are the distant, home, and starting signals interlocked with each other, but with the signals and points governing the approach of a train from the opposite direction--in other words, the signals for the approach of a train to a station from one direction cannot be lowered unless those for the approach to the station of a train from the opposite direction are at danger, and the points correctly set. signalling operations. in the working of single lines, as of double, the signalman at the station from which a train is to proceed has to obtain the consent of the signalman ahead, the series of questions to be signalled being very similar to those detailed for double lines. there is, however, one notable exception. on long lengths of single line it is necessary to make arrangements for trains to pass each other. this is done by providing loop lines at intervals, a second pair of rails being laid for the accommodation of one train while another in the opposite direction passes it. to secure that more than one train shall not be on a section of single line between two crossing-places it is laid down that, when a signalman at a non-crossing station is asked to allow a train to approach his station, he must not give permission until he has notified the signalman ahead of him, thus securing that he is not asking permission for trains to approach from both directions at the same time. both for single and double line working a number of rules designed to deal with cases of emergency are laid down, the guiding principle being safety; but we have now dealt with all the conditions of everyday working, and must pass to the consideration of [illustration: fig. .--an electric lever-frame in a signalling cabin at didcot.] "power" signalling. in a power system of signalling the signalman is provided with some auxiliary means--electricity, compressed air, etc.--of moving the signals or points under his control. it is still necessary to have a locking-frame in the signal-box, with levers interlocked with each other, and connections between the box and the various points and signals. but the frame is much smaller than an ordinary manual frame, and but little force is needed to move the little levers which make or break an electric circuit, or open an air-valve, according to the power-agent used. electric signalling. fig. represents the locking-frame of a cabin at didcot, england, where an all-electric system has been installed. wires lead from the cabin to motors situated at the points and signals, which they operate through worm gearing. when a lever is moved it closes a circuit and sets the current flowing through a motor, the direction of the flow (and consequently of the motor's revolution) depending on whether the lever has been moved forward or backward. indicators arranged under the levers tell the signalman when the desired movements at the points and signals have been completed. if any motion is not carried through, owing to failure of the current or obstruction of the working parts, an electric lock prevents him continuing operations. thus, suppose he has to open the main line to an express, he is obliged by the mechanical locking-frame to set all the points correctly before the signals can be lowered. he might move all the necessary levers in due order, yet one set of points might remain open, and, were the signals lowered, an accident would result. but this cannot happen, as the electric locks worked by the points in question block the signal levers, and until the failure has been set right, the signals must remain at "danger." the point motors are connected direct to the points; but between a signal motor and its arm there is an "electric slot," consisting of a powerful electro-magnet which forms a link in the rod work. to lower a signal it is necessary that the motor shall revolve and a control current pass round the magnet to give it the requisite attractive force. if no control current flows, as would happen were any pair of points not in their proper position, the motor can have no effect on the signal arm to lower it, owing to the magnet letting go its grip. furthermore, if the signal had been already lowered when the control current failed, it would rise to "danger" automatically, as all signals are weighted to assume the danger position by gravity. the signal control currents can be broken by the signalman moving a switch, so that in case of emergency all signals may be thrown simultaneously to danger. pneumatic signalling. in england and the united states compressed air is also used to do the hard labour of the signalman for him. instead of closing a circuit, the signalman, by moving a lever half-way over, admits air to a pipe running along the track to an air reservoir placed beside the points or signal to which the lever relates. the air opens a valve and puts the reservoir in connection with a piston operating the points or signal-arm, as the case may be. this movement having been performed, another valve in the reservoir is opened, and air passes back through a second pipe to the signal-box, where it opens a third valve controlling a piston which completes the movement of the lever, so showing the signalman that the operation is complete. with compressed air, as with electricity, a mechanical locking-frame is of course used. automatic signalling. to reduce expense, and increase the running speed on lines where the sections are short, the train is sometimes made to act as its own signalman. the rails of each section are all bonded together so as to be in metallic contact, and each section is insulated from the two neighbouring sections. at the further end of a section is installed an electric battery, connected to the rails, which lead the current back to a magnet operating a signal stationed some distance back on the preceding section. as long as current flows the signal is held at "all right." when a train enters the section the wheels and axles short-circuit the current, so that it does not reach the signal magnet, and the signal rises to "danger," and stays there until the last pair of wheels has passed out of the section. should the current fail or a vehicle break loose and remain on the section, the same thing would happen. the human element can thus be practically eliminated from signalling. to make things absolutely safe, a train should have positive control over a train following, to prevent the driver overrunning the signals. on electric railways this has been effected by means of contacts working in combination with the signals, which either cut the current off from the section preceding that on which a train may be, or raise a trigger to strike an arm on the train following and apply its brakes. chapter xii. optics. lenses--the image cast by a convex lens--focus--relative position of object and lens--correction of lenses for colour--spherical aberration--distortion of image--the human eye--the use of spectacles--the blind spot. light is a third form of that energy of which we have already treated two manifestations--heat and electricity. the distinguishing characteristic of ether light-waves is their extreme rapidity of vibration, which has been calculated to range from billion movements per second for violet rays to billion for red rays. if a beam of white light be passed through a prism it is resolved into the seven visible colours of the spectrum--violet, indigo, blue, green, yellow, orange, and red--in this order. the human eye is most sensitive to the yellow-red rays, a photographic plate to the green-violet rays. all bodies fall into one of two classes--( ) _luminous_--that is, those which are a _source_ of light, such as the sun, a candle flame, or a red-hot coal; and ( ) _non-luminous_, which become visible only by virtue of light which they receive from other bodies and reflect to our eyes. the propagation of light. light naturally travels in a straight line. it is deflected only when it passes from one transparent medium into another--for example, from air to water--and the mediums are of different densities. we may regard the surface of a visible object as made up of countless points, from each of which a diverging pencil of rays is sent off through the ether. lenses. if a beam of light encounters a transparent glass body with non-parallel sides, the rays are deflected. the direction they take depends on the shape of the body, but it may be laid down as a rule that they are bent toward the thicker part of the glass. the common burning-glass is well known to us. we hold it up facing the sun to concentrate all the heat rays that fall upon it into one intensely brilliant spot, which speedily ignites any inflammable substance on which it may fall (fig. ). we may imagine that one ray passes from the centre of the sun through the centre of the glass. this is undeflected; but all the others are bent towards it, as they pass through the thinner parts of the lens. [illustration: fig. .--showing how a burning-glass concentrates the heat rays which fall upon it.] it should be noted here that _sunlight_, as we call it, is accompanied by heat. a burning-glass is used to concentrate the _heat_ rays, not the _light_ rays, which, though they are collected too, have no igniting effect. in photography we use a lens to concentrate light rays only. such heat rays as may pass through the lens with them are not wanted, and as they have no practical effect are not taken any notice of. to be of real value, a lens must be quite symmetrical--that is, the curve from the centre to the circumference must be the same in all directions. there are six forms of simple lenses, as given in fig. . nos. and have one flat and one spherical surface. nos. , , , have two spherical surfaces. when a lens is thicker at the middle than at the sides it is called a _convex_ lens; when thinner, a _concave_ lens. the names of the various shapes are as follows:--no. , plano-convex; no. , plano-concave; no. , double convex; no. , double concave; no. , meniscus; no. , concavo-convex. the thick-centre lenses, as we may term them (nos. , , ), _concentrate_ a pencil of rays passing through them; while the thin-centre lenses (nos. , , ) _scatter_ the rays (see fig. ). [illustration: fig. .--six forms of lenses.] the camera. [illustration: fig. .] [illustration: fig. .] we said above that light is propagated in straight lines. to prove this is easy. get a piece of cardboard and prick a hole in it. set this up some distance away from a candle flame, and hold behind it a piece of tissue paper. you will at once perceive a faint, upside-down image of the flame on the tissue. why is this? turn for a moment to fig. , which shows a "pinhole" camera in section. at the rear is a ground-glass screen, b, to catch the image. suppose that a is the lowest point of the flame. a pencil of rays diverging from it strikes the front of the camera, which stops them all except the one which passes through the hole and makes a tiny luminous spot on b, _above_ the centre of the screen, though a is below the axis of the camera. similarly the tip of the flame (above the axis) would be represented by a dot on the screen below its centre. and so on for all the millions of points of the flame. if we were to enlarge the hole we should get a brighter image, but it would have less sharp outlines, because a number of rays from every point of the candle would reach the screen and be jumbled up with the rays of neighbouring pencils. now, though a good, sharp photograph may be taken through a pinhole, the time required is so long that photography of this sort has little practical value. what we want is a large hole for the light to enter the camera by, and yet to secure a distinct image. if we place a lens in the hole we can fulfil our wish. fig. shows a lens in position, gathering up a number of rays from a point, a, and focussing them on a point, b. if the lens has , times the area of the pinhole, it will pass , times as many rays, and the image of a will be impressed on a sensitized photographic plate , times more quickly. [illustration: fig. .] the image cast by a convex lens. fig. shows diagrammatically how a convex lens forms an image. from a and b, the extremities of the object, a simple ray is considered to pass through the centre of the lens. this is not deflected at all. two other rays from the same points strike the lens above and below the centre respectively. these are bent inwards and meet the central rays, or come to a focus with them at a^ and b^ . in reality a countless number of rays would be transmitted from every point of the object and collected to form the image. [illustration: fig. .--showing how an image is cast by a convex lens.] focus. we must now take special notice of that word heard so often in photographic talk--"focus." what is meant by the focus or focal length of a lens? well, it merely signifies the distance between the optical centre of the lens and the plane in which the image is formed. [illustration: fig. .] we must here digress a moment to draw attention to the three simple diagrams of fig. . the object, o, in each case is assumed to be to the right of the lens. in the topmost diagram the object is so far away from the lens that all rays coming from a single point in it are practically parallel. these converge to a focus at f. if the distance between f and the centre of the lens is six inches, we say that the lens has a six-inch focal length. the focal length of a lens is judged by the distance between lens and image when the object is far away. to avoid confusion, this focal length is known as the _principal_ focus, and is denoted by the symbol f. in the middle diagram the object is quite near the lens, which has to deal with rays striking its nearer surface at an acuter angle than before (reckoning from the centre). as the lens can only deflect their path to a fixed degree, they will not, after passing the lens, come together until they have reached a point, f^ , further from the lens than f. the nearer we approach o to the lens, the further away on the other side is the focal point, until a distance equal to that of f from the lens is reached, when the rays emerge from the glass in a parallel pencil. the rays now come to a focus no longer, and there can be no image. if o be brought nearer than the focal distance, the rays would _diverge_ after passing through the lens. relative positions of object and image. [illustration: fig. .--showing how the position of the image alters relatively to the position of the object.] from what has been said above we deduce two main conclusions--( .) the nearer an object is brought to the lens, the further away from the lens will the image be. ( .) if the object approaches within the principal focal distance of the lens, no image will be cast by the lens. to make this plainer we append a diagram (fig. ), which shows five positions of an object and the relative positions of the image (in dotted lines). first, we note that the line a b, or a b^ , denotes the principal focal length of the lens, and a c, or a c^ , denotes twice the focal length. we will take the positions in order:-- _position i._ object further away than _f_. inverted image _smaller_ than object, at distance somewhat exceeding _f_. _position ii._ object at distance = _f_. inverted image at distance = _f_, and of size equal to that of object. _position iii_ object nearer than _f_. inverted image further away than _f_; _larger_ than the object. _position iv._ object at distance = _f_. as rays are parallel after passing the lens _no_ image is cast. _position v._ object at distance less than _f_. no real image--that is, one that can be caught on a focussing screen--is now given by the lens, but a magnified, erect, _virtual_ image exists on the same side of the lens as the object. we shall refer to _virtual_ images at greater length presently. it is hoped that any reader who practises photography will now understand why it is necessary to rack his camera out beyond the ordinary focal distance when taking objects at close quarters. from fig. he may gather one practically useful hint--namely, that to copy a diagram, etc., full size, both it and the plate must be exactly _f_ from the optical centre of the lens. and it follows from this that the further he can rack his camera out beyond _f_ the greater will be the possible enlargement of the original. correction of lenses for colour. we have referred to the separation of the spectrum colours of white light by a prism. now, a lens is one form of prism, and therefore sorts out the colours. in fig. we assume that two parallel red rays and two parallel violet rays from a distant object pass through a lens. a lens has most bending effect on violet rays and least on red, and the other colours of the spectrum are intermediately influenced. for the sake of simplicity we have taken the two extremes only. you observe that the point r, in which the red rays meet, is much further from the lens than is v, the meeting-point of the violet rays. a photographer very seldom has to take a subject in which there are not objects of several different colours, and it is obvious that if he used a simple lens like that in fig. and got his red objects in good focus, the blue and green portions of his picture would necessarily be more or less out of focus. [illustration: fig. .] [illustration: fig. .] this defect can fortunately be corrected by the method shown in fig. . a _compound_ lens is needed, made up of a _crown_ glass convex element, b, and a concave element, a, of _flint_ glass. for the sake of illustration the two parts are shown separated; in practice they would be cemented together, forming one optical body, thicker in the centre than at the edges--a meniscus lens in fact, since a is not so concave as b is convex. now, it was discovered by a mr. hall many years ago that if white light passed through two similar prisms, one of flint glass the other of crown glass, the former had the greater effect in separating the spectrum colours--that is, violet rays were bent aside more suddenly compared with the red rays than happened with the crown-glass prism. look at fig. . the red rays passing through the flint glass are but little deflected, while the violet rays turn suddenly outwards. this is just what is wanted, for it counteracts the unequal inward refraction by b, and both sets of rays come to a focus in the same plane. such a lens is called _achromatic_, or colourless. if you hold a common reading-glass some distance away from large print you will see that the letters are edged with coloured bands, proving that the lens is not achromatic. a properly corrected photographic lens would not show these pretty edgings. colour correction is necessary also for lenses used in telescopes and microscopes. spherical aberration. a lens which has been corrected for colour is still imperfect. if rays pass through all parts of it, those which strike it near the edge will be refracted more than those near the centre, and a blurred focus results. this is termed _spherical aberration_. you will be able to understand the reason from figs. and . two rays, a, are parallel to the axis and enter the lens near the centre (fig. ). these meet in one plane. two other rays, b, strike the lens very obliquely near the edge, and on that account are both turned sharply upwards, coming to a focus in a plane nearer the lens than a. if this happened in a camera the results would be very bad. either a or b would be out of focus. the trouble is minimized by placing in front of the lens a plate with a central circular opening in it (denoted by the thick, dark line in fig. ). the rays b of fig. are stopped by this plate, which is therefore called a _stop_. but other rays from the same point pass through the hole. these, however, strike the lens much more squarely above the centre, and are not unduly refracted, so that they are brought to a focus in the same plane as rays a. [illustration: fig. .] [illustration: fig. .] distortion of image. [illustration: fig. .--section of a rectilinear lens.] the lens we have been considering is a single meniscus, such as is used in landscape photography, mounted with the convex side turned towards the inside of the camera, and having the stop in front of it. if you possess a lens of this sort, try the following experiment with it. draw a large square on a sheet of white paper and focus it on the screen. the sides instead of being straight bow outwards: this is called _barrel_ distortion. now turn the lens mount round so that the lens is outwards and the stop inwards. the sides of the square will appear to bow towards the centre: this is _pin-cushion_ distortion. for a long time opticians were unable to find a remedy. then mr. george s. cundell suggested that _two_ meniscus lenses should be used in combination, one on either side of the stop, as in fig . each produces distortion, but it is counteracted by the opposite distortion of the other, and a square is represented as a square. lenses of this kind are called _rectilinear_, or straight-line producing. we have now reviewed the three chief defects of a lens--chromatic aberration, spherical aberration, and distortion--and have seen how they may be remedied. so we will now pass on to the most perfect of cameras, the human eye. the eye (fig. ) is nearly spherical in form, and is surrounded outside, except in front, by a hard, horny coat called the _sclerotica_ (s). in front is the _cornea_ (a), which bulges outwards, and acts as a transparent window to admit light to the lens of the eye (c). inside the sclerotica, and next to it, comes the _choroid_ coat; and inside that again is the _retina_, or curved focussing screen of the eye, which may best be described as a network of fibres ramifying from the optic nerve, which carries sight sensations to the brain. the hollow of the ball is full of a jelly-like substance called the _vitreous humour_; and the cavity between the lens and the cornea is full of water. we have already seen that, in focussing, the distance between lens and image depends on the distance between object and lens. now, the retina cannot be pushed nearer to or pulled further away from its lens, like the focussing screen of a camera. how, then, is the eye able to focus sharply objects at distances varying from a foot to many miles? [illustration: fig. .--section of the human eye.] as a preliminary to the answer we must observe that the more convex a lens is, the shorter is its focus. we will suppose that we have a box camera with a lens of six-inch focus fixed rigidly in the position necessary for obtaining a sharp image of distant objects. it so happens that we want to take with it a portrait of a person only a few feet from the lens. if it were a bellows camera, we should rack out the back or front. but we cannot do this here. so we place in front of our lens a second convex lens which shortens its principal focus; so that _in effect_ the box has been racked out sufficiently. nature, however, employs a much more perfect method than this. the eye lens is plastic, like a piece of india-rubber. its edges are attached to ligaments (l l), which pull outwards and tend to flatten the curve of its surfaces. the normal focus is for distant objects. when we read a book the eye adapts itself to the work. the ligaments relax and the lens decreases in diameter while thickening at the centre, until its curvature is such as to focus all rays from the book sharply on the retina. if we suddenly look through the window at something outside, the ligaments pull on the lens envelope and flatten the curves. this wonderful lens is achromatic, and free from spherical aberration and distortion of image. nor must we forget that it is aided by an automatic "stop," the _iris_, the central hole of which is named the _pupil_. we say that a person has black, blue, or gray eyes according to the colour of the iris. like the lens, the iris adapts itself to all conditions, contracting when the light is strong, and opening when the light is weak, so that as uniform an amount of light as conditions allow may be admitted to the eye. most modern camera lenses are fitted with adjustable stops which can be made larger or smaller by twisting a ring on the mount, and are named "iris" stops. the image of anything seen is thrown on the retina upside down, and the brain reverses the position again, so that we get a correct impression of things. the use of spectacles. [illustration: fig. _a_.] [illustration: fig. _b_.] [illustration: fig. _a_.] [illustration: fig. _b_.] the reader will now be able to understand without much trouble the function of a pair of spectacles. a great many people of all ages suffer from short-sight. for one reason or another the distance between lens and retina becomes too great for a person to distinguish distant objects clearly. the lens, as shown in fig _a_, is too convex--has its minimum focus too short--and the rays meet and cross before they reach the retina, causing general confusion of outline. this defect is simply remedied by placing in front of the eye (fig. _b_) a _concave_ lens, to disperse the rays somewhat before they enter the eye, so that they come to a focus on the retina. if a person's sight is thus corrected for distant objects, he can still see near objects quite plainly, as the lens will accommodate its convexity for them. the scientific term for short-sight is _myopia_. long-sight, or _hypermetropia_, signifies that the eyeball is too short or the lens too flat. fig. _a_ represents the normal condition of a long-sighted eye. when looking at a distant object the eye thickens slightly and brings the focus forward into the retina. but its thickening power in such an eye is very limited, and consequently the rays from a near object focus behind the retina. it is therefore necessary for a long-sighted person to use _convex_ spectacles for reading the newspaper. as seen in fig. _b_, the spectacle lens concentrates the rays before they enter the eye, and so does part of the eye's work for it. returning for a moment to the diagram of the eye (fig. ), we notice a black patch on the retina near the optic nerve. this is the "yellow spot." vision is most distinct when the image of the object looked at is formed on this part of the retina. the "blind spot" is that point at which the optic nerve enters the retina, being so called from the fact that it is quite insensitive to light. the finding of the blind spot is an interesting little experiment. on a card make a large and a small spot three inches apart, the one an eighth, the other half an inch in diameter. bring the card near the face so that an eye is exactly opposite to each spot, and close the eye opposite to the smaller. now direct the other eye to this spot and you will find, if the card be moved backwards and forwards, that at a certain distance the large spot, though many times larger than its fellow, has completely vanished, because the rays from it enter the open eye obliquely and fall on the "blind spot." chapter xiii. the microscope, the telescope, and the magic-lantern. the simple microscope--use of the simple microscope in the telescope--the terrestrial telescope--the galilean telescope--the prismatic telescope--the reflecting telescope--the parabolic mirror--the compound microscope--the magic-lantern--the bioscope--the plane mirror. in fig. is represented an eye looking at a vase, three inches high, situated at a, a foot away. if we were to place another vase, b, six inches high, at a distance of two feet; or c, nine inches high, at three feet; or d, a foot high, at four feet, the image on the retina would in every case be of the same size as that cast by a. we can therefore lay down the rule that _the apparent size of an object depends on the angle that it subtends at the eye_. [illustration: fig. .] to see a thing more plainly, we go nearer to it; and if it be very small, we hold it close to the eye. there is, however, a limit to the nearness to which it can be brought with advantage. the normal eye is unable to adapt its focus to an object less than about ten inches away, termed the "least distance of distinct vision." the simple microscope. [illustration: fig. .] a magnifying glass comes in useful when we want to examine an object very closely. the glass is a lens of short focus, held at a distance somewhat less than its principal focal length, f (see fig. ), from the object. the rays from the head and tip of the pin which enter the eye are denoted by continuous lines. as they are deflected by the glass the eye gets the _impression_ that a much longer pin is situated a considerable distance behind the real object in the plane in which the refracted rays would meet if produced backwards (shown by the dotted lines). the effect of the glass, practically, is to remove it (the object) to beyond the least distance of distinct vision, and at the same time to retain undiminished the angle it subtends at the eye, or, what amounts to the same thing, the actual size of the image formed on the retina.[ ] it follows, therefore, that if a lens be of such short focus that it allows us to see an object clearly at a distance of two inches--that is, one-fifth of the least distance of distinct vision--we shall get an image on the retina five times larger in diameter than would be possible without the lens. the two simple diagrams (figs. and ) show why the image to be magnified should be nearer to the lens than the principal focus, f. we have already seen (fig. ) that rays coming from a point in the principal focal plane emerge as a parallel pencil. these the eye can bring to a focus, because it normally has a curvature for focussing parallel rays. but, owing to the power of "accommodation," it can also focus _diverging_ rays (fig. ), the eye lens thickening the necessary amount, and we therefore put our magnifying glass a bit nearer than f to get full advantage of proximity. if we had the object _outside_ the principal focus, as in fig. , the rays from it would converge, and these could not be gathered to a sharp point by the eye lens, as it cannot _flatten_ more than is required for focussing parallel rays. [illustration: fig. .] [illustration: fig. .] use of the simple microscope in the telescope. [illustration: fig. .] let us now turn to fig. . at a is a distant object, say, a hundred yards away. b is a double convex lens, which has a focal length of twenty inches. we may suppose that it is a lens in a camera. an inverted image of the object is cast by the lens at c. if the eye were placed at c, it would distinguish nothing. but if withdrawn to d, the least distance of distinct vision,[ ] behind c, the image is seen clearly. that the image really is at c is proved by letting down the focussing screen, which at once catches it. now, as the focus of the lens is twice _d_, the image will be twice as large as the object would appear if viewed directly without the lens. we may put this into a very simple formula:-- magnification = focal length of lens -------------------- _d_ [illustration: fig. .] in fig. we have interposed between the eye and the object a small magnifying glass of - / -inch focus, so that the eye can now clearly see the image when one-quarter _d_ away from it. b already magnifies the image twice; the eye-piece again magnifies it four times; so that the total magnification is × = times. this result is arrived at quickly by dividing the focus of b (which corresponds to the object-glass of a telescope) by the focus of the eye-piece, thus:-- ____ = - / the ordinary astronomical telescope has a very long focus object-glass at one end of the tube, and a very short focus eye-piece at the other. to see an object clearly one merely has to push in or pull out the eye-piece until its focus exactly corresponds with that of the object-glass. the terrestrial telescope. an astronomical telescope inverts images. this inversion is inconvenient for other purposes. so the terrestrial telescope (such as is commonly used by sailors) has an eye-piece compounded of four convex lenses which erect as well as magnify the image. fig. shows the simplest form of compound erecting eye-piece. [illustration: fig. .] the galilean telescope. [illustration: fig. .] a third form of telescope is that invented by the great italian astronomer, galileo,[ ] in . its principle is shown in fig. . the rays transmitted by the object-glass are caught, _before_ coming to a focus, on a concave lens which separates them so that they appear to meet in the paths of convergence denoted by the dotted lines. the image is erect. opera-glasses are constructed on the galilean principle. the prismatic telescope. in order to be able to use a long-focus object-glass without a long focussing-tube, a system of glass reflecting prisms is sometimes employed, as in fig. . a ray passing through the object-glass is reflected from one posterior surface of prism a on to the other posterior surface, and by it out through the front on to a second prism arranged at right angles to it, which passes the ray on to the compound eye-piece. the distance between object-glass and eye-piece is thus practically trebled. the best-known prismatic telescopes are the zeiss field-glasses. [illustration: fig. .] the reflecting telescope. we must not omit reference to the _reflecting_ telescope, so largely used by astronomers. the front end of the telescope is open, there being no object-glass. rays from the object fall on a parabolic mirror situated in the rear end of the tube. this reflects them forwards to a focus. in the newtonian reflector a plane mirror or prism is situated in the axis of the tube, at the focus, to reflect the rays through an eye-piece projecting through the side of the tube. herschel's form of reflector has the mirror set at an angle to the axis, so that the rays are reflected direct into an eye-piece pointing through the side of the tube towards the mirror. the parabolic mirror. this mirror (fig. ) is of such a shape that all rays parallel to the axis are reflected to a common point. in the marine searchlight a powerful arc lamp is arranged with the arc at the focus of a parabolic reflector, which sends all reflected light forward in a pencil of parallel rays. the most powerful searchlight in existence gives a light equal to that of million candles. [illustration: fig. .--a parabolic reflector.] the compound microscope. we have already observed (fig. ) that the nearer an object approaches a lens the further off behind it is the real image formed, until the object has reached the focal distance, when no image at all is cast, as it is an infinite distance behind the lens. we will assume that a certain lens has a focus of six inches. we place a lighted candle four feet in front of it, and find that a _sharp_ diminished image is cast on a ground-glass screen held seven inches behind it. if we now exchange the positions of the candle and the screen, we shall get an enlarged image of the candle. this is a simple demonstration of the law of _conjugate foci_--namely, that the distance between the lens and an object on one side and that between the lens and the corresponding image on the other bear a definite relation to each other; and an object placed at either focus will cast an image at the other. whether the image is larger or smaller than the object depends on which focus it occupies. in the case of the object-glass of a telescope the image was at what we may call the _short_ focus. [illustration: fig. .--diagram to explain the compound microscope.] now, a compound microscope is practically a telescope with the object at the _long_ focus, very close to a short-focus lens. a greatly enlarged image is thrown (see fig. ) at the conjugate focus, and this is caught and still further magnified by the eye-piece. we may add that the object-glass, or _objective_, of a microscope is usually compounded of several lenses, as is also the eye-piece. the magic-lantern. the most essential features of a magic-lantern are:--( ) the _source of light_; ( ) the _condenser_ for concentrating the light rays on to the slide; ( ) the _lens_ for projecting a magnified image on to a screen. fig. shows these diagrammatically. the _illuminant_ is most commonly an oil-lamp, or an acetylene gas jet, or a cylinder of lime heated to intense luminosity by an oxy-hydrogen flame. the natural combustion of hydrogen is attended by a great heat, and when the supply of oxygen is artificially increased the temperature of the flame rises enormously. the nozzle of an oxy-hydrogen jet has an interior pipe connected with the cylinder holding one gas, and an exterior, and somewhat larger, pipe leading from that containing the other, the two being arranged concentrically at the nozzle. by means of valves the proportions of the gases can be regulated to give the best results. [illustration: fig. .--sketch of the elements of a magic-lantern.] the _condenser_ is set somewhat further from the illuminant than the principal focal length of the lenses, so that the rays falling on them are bent inwards, or to the slide. the _objective_, or object lens, stands in front of the slide. its position is adjustable by means of a rack and a draw-tube. the nearer it is brought to the slide the further away is the conjugate focus (see p. ), and consequently the image. the exhibitor first sets up his screen and lantern, and then finds the conjugate foci of slide and image by racking the lens in or out. if a very short focus objective be used, subjects of microscopic proportions can be projected on the screen enormously magnified. during the siege of paris in - the parisians established a balloon and pigeon post to carry letters which had been copied in a minute size by photography. these copies could be enclosed in a quill and attached to a pigeon's wing. on receipt, the copies were placed in a special lantern and thrown as large writing on the screen. micro-photography has since then made great strides, and is now widely used for scientific purposes, one of the most important being the study of the crystalline formations of metals under different conditions. the bioscope. "living pictures" are the most recent improvement in magic-lantern entertainments. the negatives from which the lantern films are printed are made by passing a ribbon of sensitized celluloid through a special form of camera, which feeds the ribbon past the lens in a series of jerks, an exposure being made automatically by a revolving shutter during each rest. the positive film is placed in a lantern, and the intermittent movement is repeated; but now the source of illumination is behind the film, and light passes outwards through the shutter to the screen. in the urban bioscope the film travels at the rate of fifteen miles an hour, upwards of one hundred exposures being made every second. the impression of continuous movement arises from the fact that the eye cannot get rid of a visual impression in less than one-tenth of a second. so that if a series of impressions follow one another more rapidly than the eye can rid itself of them the impressions will overlap, and give one of _motion_, if the position of some of the objects, or parts of the objects, varies slightly in each succeeding picture.[ ] the plane mirror. [illustration: fig. .] this chapter may conclude with a glance at the common looking-glass. why do we see a reflection in it? the answer is given graphically by fig. . two rays, a _b_, a _c_, from a point a strike the mirror m at the points _b_ and _c_. lines _b_ n, _c_ o, drawn from these points perpendicular to the mirror are called their _normals_. the angles a _b_ n, a _c_ o are the _angles of incidence_ of rays a _b_, a _c_. the paths which the rays take after reflection must make angles with _b_ n and _c_ o respectively equal to a _b_ n, a _c_ o. these are the _angles of reflection_. if the eye is so situated that the rays enter it as in our illustration, an image of the point a is seen at the point a^ , in which the lines d _b_, e _c_ meet when produced backwards. [illustration: fig. .] when the vertical mirror is replaced by a horizontal reflecting surface, such as a pond (fig. ), the same thing happens. the point at which the ray from the reflection of the spire's tip to the eye appears to pass through the surface of the water must be so situated that if a line were drawn perpendicular to it from the surface the angles made by lines drawn from the real spire tip and from the observer's eye to the base of the perpendicular would be equal. [ ] glazebrook, "light," p. . [ ] glazebrook, "light," p. . [ ] galileo was severely censured and imprisoned for daring to maintain that the earth moved round the sun, and revolved on its axis. [ ] for a full account of animated pictures the reader might advantageously consult "the romance of modern invention," pp. foll. chapter xiv. sound and musical instruments. nature of sound--the ear--musical instruments--the vibration of strings--the sounding-board and the frame of a piano--the strings--the striking mechanism--the quality of a note. sound differs from light, heat, and electricity in that it can be propagated through matter only. sound-waves are matter-waves, not ether-waves. this can be proved by placing an electric bell under the bell-glass of an air-pump and exhausting all the air. ether still remains inside the glass, but if the bell be set in motion no sound is audible. admit air, and the clang of the gong is heard quite plainly. sound resembles light and heat, however, thus far, that it can be concentrated by means of suitable lenses and curved surfaces. an _echo_ is a proof of its _reflection_ from a surface. before dealing with the various appliances used for producing sound-waves of a definite character, let us examine that wonderful natural apparatus the ear, through which we receive those sensations which we call sound. [illustration: fig. .--diagrammatic sketch of the parts of the ear.] fig. is a purely diagrammatic section of the ear, showing the various parts distorted and out of proportion. beginning at the left, we have the _outer ear_, the lobe, to gather in the sound-waves on to the membrane of the tympanum, or drum, to which is attached the first of a series of _ossicles_, or small bones. the last of these presses against an opening in the _inner ear_, a cavity surrounded by the bones of the head. inside the inner ear is a watery fluid, p, called _perilymph_ ("surrounding water"), immersed in which is a membranic envelope, m, containing _endolymph_ ("inside water"), also full of fluid. into this fluid project e e e, the terminations of the _auditory nerve_, leading to the brain. when sound-waves strike the tympanum, they cause it to move inwards and outwards in a series of rapid movements. the ossicles operated by the tympanum press on the little opening o, covered by a membrane, and every time they push it in they slightly squeeze the perilymph, which in turn compresses the endolymph, which affects the nerve-ends, and telegraphs a sensation of sound to the brain. in fig. we have a more developed sketch, giving in fuller detail, though still not in their actual proportions, the components of the ear. the ossicles m, i, and s are respectively the _malleus_ (hammer), _incus_ (anvil), and _stapes_ (stirrup). each is attached by ligaments to the walls of the middle ear. the tympanum moves the malleus, the malleus the incus, and the incus the stapes, the last pressing into the opening o of fig. , which is scientifically known as the _fenestra ovalis_, or oval window. as liquids are practically incompressible, nature has made allowance for the squeezing in of the oval window membrane, by providing a second opening, the round window, also covered with a membrane. when the stapes pushes the oval membrane in, the round membrane bulges out, its elasticity sufficing to put a certain pressure on the perilymph (indicated by the dotted portion of the inner ear). [illustration: fig. .--diagrammatic section of the ear, showing the various parts.] the inner ear consists of two main parts, the _cochlea_--so called from its resemblance in shape to a snail's shell--and the _semicircular canals_. each portion has its perilymph and endolymph, and contains a number of the nerve-ends, which are, however, most numerous in the cochlea. we do not know for certain what the functions of the canals and the cochlea are; but it is probable that the former enables us to distinguish between the _intensity_ or loudness of sounds and the direction from which they come, while the latter enables us to determine the _pitch_ of a note. in the cochlea are about , tiny nerve-ends, called the _rods of corti_. the normal ear has such a range as to give about rods to the semitone. the great scientist helmholtz has advanced the theory that these little rods are like tiny tuning-forks, each responding to a note of a certain pitch; so that when a string of a piano is sounded and the air vibrations are transmitted to the inner ear, they affect only one of these rods and the part of the brain which it serves, and we have the impression of one particular note. it has been proved by experiment that a very sensitive ear can distinguish between sounds varying in pitch by only / th of a semitone, or but half the range of any one corti fibre. this difficulty helmholtz gets over by suggesting that in such an ear two adjacent fibres are affected, but one more than the other. a person who has a "good ear" for music is presumably one whose corti rods are very perfect. unlucky people like the gentleman who could only recognize one tune, and that because people took off their hats when it commenced, are physically deficient. their corti rods cannot be properly developed. what applies to one single note applies also to the elements of a musical chord. a dozen notes may sound simultaneously, but the ear is able to assimilate each and blend it with its fellows; yet it requires a very sensitive and well-trained ear to pick out any one part of a harmony and concentrate the brain's attention on that part. the ear has a much larger range than the eye. "while the former ranges over eleven octaves, but little more than a single octave is possible to the latter. the quickest vibrations which strike the eye, as light, have only about twice the rapidity of the slowest; whereas the quickest vibrations which strike the ear, as a musical sound, have more than two thousand times the rapidity of the slowest."[ ] to come to actual figures, the ordinary ear is sensitive to vibrations ranging from to , per second. the bottom and top notes of a piano make respectively about and , vibrations a second. of course, some ears, like some eyes, cannot comprehend the whole scale. the squeak of bats and the chirrup of crickets are inaudible to some people; and dogs are able to hear sounds far too shrill to affect the human auditory apparatus. not the least interesting part of this wonderful organ is the tympanic membrane, which is provided with muscles for altering its tension automatically. if we are "straining our ears" to catch a shrill sound, we tighten the membrane; while if we are "getting ready" for a deep, loud report like that of a gun, we allow the drum to slacken. the _eustachian tube_ (fig. ) communicates with the mouth. its function is probably to keep the air-pressure equal on both sides of the drum. when one catches cold the tube is apt to become blocked by mucus, causing unequal pressure and consequent partial deafness. before leaving this subject, it will be well to remind our more youthful readers that the ear is delicately as well as wonderfully made, and must be treated with respect. sudden shouting into the ear, or a playful blow, may have most serious effects, by bursting the tympanum or injuring the arrangement of the tiny bones putting it in communication with the inner ear. musical instruments. these are contrivances for producing sonorous shocks following each other rapidly at regular intervals. musical sounds are distinguished from mere noises by their regularity. if we shake a number of nails in a tin box, we get only a series of superimposed and chaotic sensations. on the other hand, if we strike a tuning-fork, the air is agitated a certain number of times a second, with a pleasant result which we call a note. we will begin our excursion into the region of musical instruments with an examination of that very familiar piece of furniture, the pianoforte, which means literally the "soft-strong." by many children the piano is regarded as a great nuisance, the swallower-up of time which could be much more agreeably occupied, and is accordingly shown much less respect than is given to a phonograph or a musical-box. yet the modern piano is a very clever piece of work, admirably adapted for the production of sweet melody--if properly handled. the two forms of piano now generally used are the _upright_, with vertical sound-board and wires, and the _grand_, with horizontal sound-board.[ ] the vibration of strings. as the pianoforte is a stringed instrument, some attention should be given to the subject of the vibration of strings. a string in a state of tension emits a note when plucked and allowed to vibrate freely. the _pitch_ of the note depends on several conditions:--( ) the diameter of the string; ( ) the tension of the string; ( ) the length of the string; ( ) the substance of the string. taking them in order:--( .) the number of vibrations per second is inversely proportional to the diameter of the string: thus, a string one-quarter of an inch in diameter would vibrate only half as often in a given time as a string one-eighth of an inch in diameter. ( .) the length remaining the same, the number of vibrations is directly proportional to the _square root_ of the _tension_: thus, a string strained by a -lb. weight would vibrate four times as fast as it would if strained by a -lb. weight. ( .) the number of vibrations is inversely proportional to the _length_ of the string: thus, a one-foot string would vibrate twice as fast as a two-foot string, strained to the same tension, and of equal diameter and weight. ( .) other things being equal, the rate of vibration is inversely proportional to the square root of the _density_ of the substance: so that a steel wire would vibrate more rapidly than a platinum wire of equal diameter, length, and tension. these facts are important to remember as the underlying principles of stringed instruments. now, if you hang a wire from a cord, and hang a heavy weight from the wire, the wire will be in a state of high tension, and yield a distinct note if struck. but the volume of sound will be very small, much too small for a practical instrument. the surface of the string itself is so limited that it sets up but feeble motions in the surrounding air. now hang the wire from a large board and strike it again. the volume of sound has greatly increased, because the string has transmitted its vibrations to the large surface of the board. to get the full sound-value of the vibrations of a string, we evidently ought to so mount the string that it may influence a large sounding surface. in a violin this is effected by straining the strings over a "bridge" resting on a hollow box made of perfectly elastic wood. draw the bow across a string. the loud sound heard proceeds not from the string only, but also from the whole surface of the box. the sounding-board and frame of a piano. a piano has its strings strained across a _frame_ of wood or steel, from a row of hooks in the top of the frame to a row of tapering square-ended pins in the bottom, the wires passing over sharp edges near both ends. the tuner is able, on turning a pin, to tension its strings till it gives any desired note. readers may be interested to learn that the average tension of a string is lbs., so that the total strain on the frame of a grand piano is anything between and _tons_. to the back of the frame is attached the _sounding-board_, made of spruce fir (the familiar christmas tree). this is obtained from central and eastern europe, where it is carefully selected and prepared, as it is essential that the timber should be sawn in such a way that the grain of the wood runs in the proper direction. the strings. these are made of extremely strong steel wire of the best quality. if you examine the wires of your piano, you will see that they vary in thickness, the thinnest being at the treble end of the frame. it is found impracticable to use wires of the same gauge and the same tension throughout. the makers therefore use highly-tensioned thick wires for the bass, and finer, shorter wires for the treble, taking advantage of the three factors--weight, tension, and length--which we have noticed above. the wires for the deepest notes are wrapped round with fine copper wire to add to their weight without increasing their diameter at the tuning-pins. there are about yards (roughly one-third of a mile) of wire in a grand piano. the striking mechanism. we now pass to the apparatus for putting the strings in a state of vibration. the grand piano mechanism shown in fig. may be taken as typical of the latest improvements. the essentials of an effective mechanism are:--( ) that the blow delivered shall be sharp and certain; ( ) that the string shall be immediately "damped," or have its vibration checked if required, so as not to interfere with the succeeding notes of other strings; ( ) that the hammer shall be able to repeat the blows in quick succession. the _hammer_ has a head of mahogany covered with felt, the thickness of which tapers gradually and regularly from an inch and a quarter at the bass end to three-sixteenths of an inch at the extreme treble notes. the entire eighty-five hammers for the piano are covered all together in one piece, and then they are cut apart from each other. the consistency of the covering is very important. if too hard, it yields a harsh note, and must be reduced to the right degree by pricking with a needle. in the diagram the felt is indicated by the dotted part. [illustration: fig. .--the striking mechanism of a "grand" piano.] the _action carriage_ which operates the hammer is somewhat complicated. when the key is depressed, the left end rises, and pushes up the whole carriage, which is pivoted at one end. the hammer shank is raised by the jack b pressing upon a knob, n, called the _notch_, attached to the under side of the shank. when the jack has risen to a certain point, its arm, b^ , catches against the button c and jerks it from under the notch at the very moment when the hammer strikes, so that it may not be blocked against the string. as it rebounds, the hammer is caught on the _repetition lever_ r, which lifts it to allow of perfect repetition. the _check_ catches the tail of the hammer head during its descent when the key is raised, and prevents it coming back violently on the carriage and rest. the tail is curved so as to wedge against the check without jamming in any way. the moment the carriage begins to rise, the rear end of the key lifts a lever connected with the _damper_ by a vertical wire, and raises the damper of the string. if the key is held down, the vibrations continue for a long time after the blow; but if released at once, the damper stifles them as the hammer regains its seat. a bar, l, passing along under all the _damper lifters_, is raised by depressing the loud pedal. the _soft pedal_ slides the whole keyboard along such a distance that the hammers strike two only out of the three strings allotted to all except the bass notes, which have only one string apiece, or two, according to their depth or length. in some pianos the soft pedal presses a special damper against the strings; and a third kind of device moves the hammers nearer the strings so that they deliver a lighter blow. these two methods of damping are confined to upright pianos. a high-class piano is the result of very careful workmanship. the mechanism of each note must be accurately regulated by its tiny screws to a minute fraction of an inch. it must be ensured that every hammer strikes its blow at exactly the right place on the string, since on this depends the musical value of the note. the adjustment of the dampers requires equal care, and the whole work calls for a sensitive ear combined with skilled mechanical knowledge, so that the instrument may have a light touch, strength, and certainty of action throughout the whole keyboard. the quality of a note. if two strings, alike in all respects and equally tensioned, are plucked, both will give the same note, but both will not necessarily have the same quality of tone. the quality, or _timbre_, as musicians call it, is influenced by the presence of _overtones_, or _harmonics_, in combination with the _fundamental_, or deepest, tone of the string. the fact is, that while a vibrating string vibrates as a whole, it also vibrates in parts. there are, as it were, small waves superimposed on the big fundamental waves. points of least motion, called _nodes_, form on the string, dividing it into two, three, four, five, etc., parts, which may be further divided by subsidiary nodes. the string, considered as halved by one node, gives the first overtone, or octave of the fundamental. it may also vibrate as three parts, and give the second overtone, or twelfth of the fundamental;[ ] and as four parts, and give the third overtone, the double octave. now, if a string be struck at a point corresponding to a node, the overtones which require that point for a node will be killed, on account of the excessive motion imparted to the string at that spot. thus to hit it at the middle kills the octave, the double octave, etc.; while to hit it at a point one-third of the length from one end stifles the twelfth and all its sub-multiples. a fundamental note robbed of all its harmonics is hard to obtain, which is not a matter for regret, as it is a most uninteresting sound. to get a rich tone we must keep as many useful harmonics as possible, and therefore a piano hammer is so placed as to strike the string at a point which does not interfere with the best harmonics, but kills those which are objectionable. pianoforte makers have discovered by experiment that the most pleasing tone is excited when the point against which the hammer strikes is one-seventh to one-ninth of the length of the wire from one end. the nature of the material which does the actual striking is also of importance. the harder the substance, and the sharper the blow, the more prominent do the harmonics become; so that the worker has to regulate carefully both the duration of the blow and the hardness of the hammer covering. [ ] tyndall, "on sound," p. . [ ] a broadwood "grand" is made up of , separate pieces, and in its manufacture forty separate trades are concerned. [ ] twelve notes higher up the scale. chapter xv. wind instruments. longitudinal vibration--columns of air--resonance of columns of air--length and tone--the open pipe--the overtones of an open pipe--where overtones are used--the arrangement of the pipes and pedals--separate sound-boards--varieties of stops--tuning pipes and reeds--the bellows--electric and pneumatic actions--the largest organ in the world--human reeds. longitudinal vibration. in stringed instruments we are concerned only with the transverse vibrations of a string--that is, its movements in a direction at right angles to the axis of the string. a string can also vibrate longitudinally--that is, in the direction of its axis--as may be proved by drawing a piece of resined leather along a violin string. in this case the harmonics "step up" at the same rate as when the movements were transverse. let us substitute for a wire a stout bar of metal fixed at one end only. the longitudinal vibrations of this rod contain overtones of a different ratio. the first harmonic is not an octave, but a twelfth. while a tensioned string is divided by nodes into two, three, four, five, six, etc., parts, a rod fixed at one end only is capable of producing only those harmonics which correspond to division into three, five, seven, nine, etc., parts. therefore a free-end rod and a wire of the same fundamental note would not have the same _timbre_, or quality, owing to the difference in the harmonics. columns of air. in wind instruments we employ, instead of rods or wires, columns of air as the vibrating medium. the note of the column depends on its length. in the "penny whistle," flute, clarionet, and piccolo the length of the column is altered by closing or opening apertures in the substance encircling the column. resonance of columns of air. why does a tube closed at one end, such as the shank of a key, emit a note when we blow across the open end? the act of blowing drives a thin sheet of air against the edge of the tube and causes it to vibrate. the vibrations are confused, some "pulses" occurring more frequently than others. if we blew against the edge of a knife or a piece of wood, we should hear nothing but a hiss. but when, as in the case which we are considering, there is a partly-enclosed column of air close to the pulses, this selects those pulses which correspond to its natural period of vibration, and augments them to a sustained and very audible musical sound. [illustration: fig .--showing how the harmonics of a "stopped" pipe are formed.] in fig. , _ _ is a pipe, closed at the bottom and open at the top. a tuning-fork of the same note as the pipe is struck and held over it so that the prongs vibrate upwards and downwards. at the commencement of an outward movement of the prongs the air in front of them is _compressed_. this impulse, imparted to the air in the pipe, runs down the column, strikes the bottom, and returns. just as it reaches the top the prong is beginning to move inwards, causing a _rarefaction_ of the air behind it. this effect also travels down and back up the column of air in the pipe, reaching the prong just as it arrives at the furthest point of the inward motion. the process is repeated, and the column of air in the pipe, striking on the surrounding atmosphere at regular intervals, greatly increases the volume of sound. we must observe that if the tuning-fork were of too high or too low a note for the column of air to move in perfect sympathy with it, this increase of sound would not result. now, when we blow across the end, we present, as it were, a number of vibrating tuning-forks to the pipe, which picks out those air-pulses with which it sympathizes. length and tone. the rate of vibration is found to be inversely proportional to the length of the pipe. thus, the vibrations of a two-foot pipe are twice as rapid as those of a four-foot pipe, and the note emitted by the former is an octave higher than that of the latter. a one-foot pipe gives a note an octave higher still. we are here speaking of the _fundamental_ tones of the pipes. with them, as in the case of strings, are associated the _overtones_, or harmonics, which can be brought into prominence by increasing the pressure of the blast at the top of the pipe. blow very hard on your key, and the note suddenly changes to one much shriller. it is the twelfth of the fundamental, of which it has completely got the upper hand. we must now put on our thinking-caps and try to understand how this comes about. first, let us note that the vibration of a body (in this case a column of air) means a motion from a point of rest to a point of rest, or from node to node. in the air-column in fig. , _ _, there is only one point of rest for an impulse--namely, at the bottom of the pipe. so that to pass from node to node the impulse must pass up the pipe and down again. the distance from node to node in a vibrating body is called a _ventral segment_. remember this term. therefore the pipe represents a semi-ventral segment when the fundamental note is sounding. when the first overtone is sounded the column divides itself into two vibrating parts. where will the node between them be? we might naturally say, "half-way up." but this cannot be so; for if the node were so situated, an impulse going down the pipe would only have to travel to the bottom to find another node, while an impulse going up would have to travel to the top and back again--that is, go twice as far. so the node forms itself _one-third_ of the distance down the pipe. from b to a (fig. , _ _) and back is now equal to from b to c. when the second overtone is blown (fig. , _ _) a third node forms. the pipe is now divided into _five_ semi-ventral segments. and with each succeeding overtone another node and ventral segment are added. the law of vibration of a column of air is that the number of vibrations is directly proportional to the number of semi-ventral segments into which the column of air inside the pipe is divided.[ ] if the fundamental tone gives vibrations per second, the first overtone in a closed pipe must give , and the second vibrations. the open pipe. a pipe open at both ends is capable of emitting a note. but we shall find, if we experiment, that the note of a stopped pipe is an octave lower than that of an open pipe of equal length. this is explained by fig. , _ _. the air-column in the pipe (of the same length as that in fig. ) divides itself, when an end is blown across, into two equal portions at the node b, the natural point to obtain equilibrium. a pulse will pass from a or a^ to b and back again in half the time required to pass from a to b and back in fig. , _ _; therefore the note is an octave higher. [illustration: fig. .--showing how harmonics of an open pipe are formed, b, b^ , and c are "nodes." the arrows indicate the distance travelled by a sound impulse from a node to a node.] the overtones of an open pipe. the first overtone results when nodes form as in fig. , _ _, at points one-quarter of the length of the pipe from the ends, giving one complete ventral segment and two semi-ventral segments. the vibrations now are twice as rapid as before. the second overtone requires three nodes, as in fig. , _ _. the rate has now trebled. so that, while the overtones of a closed pipe rise in the ratio , , , , etc., those of an open pipe rise in the proportion , , , , etc. where overtones are used. in the flute, piccolo, and clarionet, as well as in the horn class of instrument, the overtones are as important as the fundamental notes. by artificially altering the length of the column of air, the fundamental notes are also altered, while the harmonics of each fundamental are produced at will by varying the blowing pressure; so that a continuous chromatic, or semitonal, scale is possible throughout the compass of the instrument. the organ. from the theory of acoustics[ ] we pass to the practical application, and concentrate our attention upon the grandest of all wind instruments, the pipe organ. this mechanism has a separate pipe for every note, properly proportioned. a section of an ordinary wooden pipe is given in fig. . wind rushes up through the foot of the pipe into a little chamber, closed by a block of wood or a plate except for a narrow slit, which directs it against the sharp lip a, and causes a fluttering, the proper pulse of which is converted by the air-column above into a musical sound. [illustration: fig. .--section of an ordinary wooden "flue" pipe.] in even the smallest organs more than one pipe is actuated by one key on the keyboard, for not only do pipes of different shapes give different qualities of tone, but it is found desirable to have ranks of pipes with their bottom note of different pitches. the length of an open pipe is measured from the edge of the lip to the top of the pipe; of a stopped pipe, from the lip to the top and back again. when we speak of a or foot rank, or stop, we mean one of which the lowest note in the rank is that produced by a or foot open pipe, or their stopped equivalents ( or foot). in a big organ we find , , , , and foot stops, and some of these repeated a number of times in pipes of different shape and construction. the arrangement of the pipes. we will now study briefly the mechanism of a very simple single-keyboard organ, with five ranks of pipes, or stops. [illustration: fig. .--the table of a sound-board.] it is necessary to arrange matters so that the pressing down of one key may make all five of the pipes belonging to it speak, or only four, three, two, or one, as we may desire. the pipes are mounted in rows on a _sound-board_, which is built up in several layers. at the top is the _upper board_; below it come the _sliders_, one for each stop; and underneath that the _table_. in fig. we see part of the table from below. across the under side are fastened parallel bars with spaces (shown black) left between them. two other bars are fastened across the ends, so that each groove is enclosed by wood at the top and on all sides. the under side of the table has sheets of leather glued or otherwise attached to it in such a manner that no air can leak from one groove to the next. upper board, sliders, and table are pierced with rows of holes, to permit the passage of wind from the grooves to the pipes. the grooves under the big pipes are wider than those under the small pipes, as they have to pass more air. the bars between the grooves also vary in width according to the weight of the pipes which they have to carry. the sliders can be moved in and out a short distance in the direction of the axis of the rows of pipes. there is one slider under each row. when a slider is in, the holes in it do not correspond with those in the table and upper board, so that no wind can get from the grooves to the rank over that particular slider. fig. shows the manner in which the sliders are operated by the little knobs (also called stops) projecting from the casing of the organ within convenient reach of the performer's hands. one stop is in, the other drawn out. [illustration: fig. .] in fig. we see the table, etc., in cross section, with a slider out, putting the pipes of its rank in communication with the grooves. the same diagram shows us in section the little triangular _pallets_ which admit air from the _wind-chest_ to the grooves; and fig. gives us an end section of table, sliders, and wind-chest, together with the rods, etc., connecting the key to its pallet. when the key is depressed, the _sticker_ (a slight wooden rod) is pushed up. this rocks a _backfall_, or pivoted lever, to which is attached the _pulldown_, a wire penetrating the bottom of the wind-chest to the pallet. as soon as the pallet opens, wind rushes into the groove above through the aperture in the leather bottom, and thence to any one of the pipes of which the slider has been drawn out. (the sliders in fig. are solid black.) it is evident that if the sound-board is sufficiently deep from back to front, any number of rows of pipes may be placed on it. [illustration: fig. .] pedals. the organ pedals are connected to the pallets by an action similar to that of the keys. the pedal stops are generally of deep tone, -foot and -foot, as they have to sustain the bass part of the musical harmonies. by means of _couplers_ one or more of the keyboard stops may be linked to the pedals. separate sound-boards. the keyboard of a very large organ has as many as five _manuals_, or rows of keys. each manual operates what is practically a separate organ mounted on its own sound-board. [illustration: fig. .] [illustration: fig. .--general section of a two-manual organ.] the manuals are arranged in steps, each slightly overhanging that below. taken in order from the top, they are:--( .) _echo organ_, of stops of small scale and very soft tone, enclosed in a "swell-box." ( .) _solo organ_, of stops imitating orchestral instruments. the wonderful "vox humana" stop also belongs to this manual. ( .) _swell organ_, contained in a swell-box, the front and sides of which have shutters which can be opened and closed by the pressure of the foot on a lever, so as to regulate the amount of sound proceeding from the pipes inside. ( .) _great organ_, including pipes of powerful tone. ( .) _choir organ_, of soft, mellow stops, often enclosed in a swell-box. we may add to these the _pedal organ_, which can be coupled to any but the echo manual. varieties of stops. we have already remarked that the quality of a stop depends on the shape and construction of the pipe. some pipes are of wood, others of metal. some are rectangular, others circular. some have parallel sides, others taper or expand towards the top. some are open, others stopped. the two main classes into which organ pipes may be divided are:--( .) _flue_ pipes, in which the wind is directed against a lip, as in fig. . ( .) _reed_ pipes--that is, pipes used in combination with a simple device for admitting air into the bottom of the pipe in a series of gusts. fig. shows a _striking_ reed, such as is found in the ordinary motor horn. the elastic metal tongue when at rest stands a very short distance away from the orifice in the reed. when wind is blown through the reed the tongue is sucked against the reed, blocks the current, and springs away again. a _free_ reed has a tongue which vibrates in a slot without actually touching the sides. harmonium and concertina reeds are of this type. in the organ the reed admits air to a pipe of the correct length to sympathize with the rate of the puffs of air which the reed passes. reed pipes expand towards the top. tuning pipes and reeds. [illustration: fig. .--a reed pipe.] pipes are tuned by adjusting their length. the plug at the top of a stopped pipe is pulled out or pushed in a trifle to flatten or sharpen the note respectively. an open pipe, if large, has a tongue cut in the side at the top, which can be pressed inwards or outwards for the purpose of correcting the tone. small metal pipes are flattened by contracting the tops inwards with a metal cone like a candle-extinguisher placed over the top and tapped; and sharpened by having the top splayed by a cone pushed in point downwards. reeds of the striking variety (see fig. ) have a tuning-wire pressing on the tongue near the fixed end. the end of this wire projects through the casing. by moving it, the length of the vibrating part of the tongue is adjusted to correctness. bellows. different stops require different wind-pressures, ranging from / lb. to lb. to the square inch, the reeds taking the heaviest pressures. there must therefore be as many sets of bellows and wind-chests as there are different pressures wanted. a very large organ consumes immense quantities of air when all the stops are out, and the pumping has to be done by a powerful gas, water, or electric engine. every bellows has a reservoir (see fig. ) above it. the top of this is weighted to give the pressure required. a valve in the top opens automatically as soon as the reservoir has expanded to a certain fixed limit, so that there is no possibility of bursting the leather sides. [illustration: fig. .--the keyboard and part of the pneumatic mechanism of the hereford cathedral organ. c, composition pedals for pushing out groups of stops; p (at bottom), pedals; p p (at top), pipes carrying compressed air; m, manuals ( ); s s, stops.] electric and pneumatic actions. we have mentioned in connection with railway signalling that the signalman is sometimes relieved of the hard manual labour of moving signals and points by the employment of electric and pneumatic auxiliaries. the same is true of organs and organists. the touch of the keys has been greatly lightened by making the keys open air-valves or complete electric circuits which actuate the mechanism for pulling down the pallets. the stops, pedals, and couplers also employ "power." not only are the performer's muscles spared a lot of heavy work when compressed air and electricity aid him, but he is able to have the _console_, or keyboard, far away from the pipes. "from the console, the player, sitting with the singers, or in any desirable part of the choir or chancel, would be able to command the working of the whole of the largest organ situated afar at the western end of the nave; would draw each stop in complete reliance on the sliders and the sound-board fulfilling their office; ... and--marvel of it all--the player, using the swell pedal in his ordinary manner, would obtain crescendo and diminuendo with a more perfect effect than by the old way."[ ] in cathedrals it is no uncommon thing for the different sound-boards to be placed in positions far apart, so that to the uninitiated there may appear to be several independent organs scattered about. yet all are absolutely under the control of a man who is sitting away from them all, but connected with them by a number of tubes or wires. the largest organ in the world is that in the town hall, sydney. it has a hundred and twenty-six speaking stops, five manuals, fourteen couplers, and forty-six combination studs. the pipes, about , in number, range from the enormous -foot contra-trombone to some only a fraction of an inch in length. the organ occupies a space feet long and feet deep. human reeds. the most wonderful of all musical reeds is found in the human throat, in the anatomical part called the _larynx_, situated at the top of the _trachea_, or windpipe. slip a piece of rubber tubing over the end of a pipe, allowing an inch or so to project. take the free part of the tube by two opposite points between the first fingers and thumbs and pull it until the edges are stretched tight. now blow through it. the wind, forcing its way between the two rubber edges, causes them and the air inside the tube to vibrate, and a musical note results. the more you strain the rubber the higher is the note. the larynx works on this principle. the windpipe takes the place of the glass pipe; the two vocal cords represent the rubber edges; and the _arytenoid muscles_ stand instead of the hands. when contracted, these muscles bring the edges of the cords nearer to one another, stretch the cords, and shorten the cords. a person gifted with a "very good ear" can, it has been calculated, adjust the length of the vocal cords to / th of an inch! simultaneously with the adjustment of the cords is effected the adjustment of the length of the windpipe, so that the column of air in it may be of the right length to vibrate in unison. here again is seen a wonderful provision of nature. the resonance of the mouth cavity is also of great importance. by altering the shape of the mouth the various harmonics of any fundamental note produced by the larynx are rendered prominent, and so we get the different vocal sounds. helmholtz has shown that the fundamental tone of any note is represented by the sound _oo_. if the mouth is adjusted to bring out the octave of the fundamental, _o_ results. _a_ is produced by accentuating the second harmonic, the twelfth; _ee_ by developing the second and fourth harmonics; while for _ah_ the fifth and seventh must be prominent. when we whistle we transform the lips into a reed and the mouth into a pipe. the tension of the lips and the shape of the mouth cavity decide the note. the lips are also used as a reed for blowing the flute, piccolo, and all the brass band instruments of the cornet order. in blowing a coach-horn the various harmonics of the fundamental note are brought out by altering the lip tension and the wind pressure. a cornet is practically a coach-horn rolled up into a convenient shape and furnished with three keys, the depression of which puts extra lengths of tubing in connection with the main tube--in fact, makes it longer. one key lowers the fundamental note of the horn half a tone; the second, a full tone; the third, a tone and a half. if the first and third are pressed down together, the note sinks two tones; if the second and third, two and a half tones; and simultaneous depression of all three gives a drop of three tones. the performer thus has seven possible fundamental notes, and several harmonics of each of these at his command; so that by a proper manipulation of the keys he can run up the chromatic scale. we should add that the cornet tube is an "open" pipe. so is that of the flute. the clarionet is a "stopped" pipe. [ ] it is obvious that in fig. , _ _, a pulse will pass from a to b and back in one-third the time required for it to pass from a to b and back in fig. , _ _. [ ] the science of hearing; from the greek verb, [greek: akouein], "to hear." [ ] "organs and tuning," p. . chapter xvi. talking-machines. the phonograph--the recorder--the reproducer--the gramophone--the making of records--cylinder records--gramophone records. in the patent office museum at south kensington is a curious little piece of machinery--a metal cylinder mounted on a long axle, which has at one end a screw thread chased along it. the screw end rotates in a socket with a thread of equal pitch cut in it. to the other end is attached a handle. on an upright near the cylinder is mounted a sort of drum. the membrane of the drum carries a needle, which, when the membrane is agitated by the air-waves set up by human speech, digs into a sheet of tinfoil wrapped round the cylinder, pressing it into a helical groove turned on the cylinder from end to end. this construction is the first phonograph ever made. thomas edison, the "wizard of the west," devised it in ; and from this rude parent have descended the beautiful machines which record and reproduce human speech and musical sounds with startling accuracy. [illustration: fig. .--the "governor" of a phonograph.] we do not propose to trace here the development of the talking-machine; nor will it be necessary to describe in detail its mechanism, which is probably well known to most readers, or could be mastered in a very short time on personal examination. we will content ourselves with saying that the wax cylinder of the phonograph, or the ebonite disc of the gramophone, is generally rotated by clockwork concealed in the body of the machine. the speed of rotation has to be very carefully governed, in order that the record may revolve under the reproducing point at a uniform speed. the principle of the governor commonly used appears in fig. . the last pinion of the clockwork train is mounted on a shaft carrying two triangular plates, a and c, to which are attached three short lengths of flat steel spring with a heavy ball attached to the centre of each. a is fixed; c moves up the shaft as the balls fly out, and pulls with it the disc d, which rubs against the pad p (on the end of a spring) and sets up sufficient friction to slow the clockwork. the limit rate is regulated by screw s. the phonograph. though the recording and reproducing apparatus of a phonograph gives very wonderful results, its construction is quite simple. at the same time, it must be borne in mind that an immense amount of experimenting has been devoted to finding out the most suitable materials and forms for the parts. [illustration: fig. .--section of an edison bell phonograph recorder.] the _recorder_ (fig. ) is a little circular box about one and a half inches in diameter.[ ] from the top a tube leads to the horn. the bottom is a circular plate, c c, hinged at one side. this plate supports a glass disc, d, about / th of an inch thick, to which is attached the cutting stylus--a tiny sapphire rod with a cup-shaped end having very sharp edges. sound-waves enter the box through the horn tube; but instead of being allowed to fill the whole box, they are concentrated by the shifting nozzle n on to the centre of the glass disc through the hole in c c. you will notice that n has a ball end, and c c a socket to fit n exactly, so that, though c c and n move up and down very rapidly, they still make perfect contact. the disc is vibrated by the sound-impulses, and drives the cutting point down into the surface of the wax cylinder, turning below it in a clockwork direction. the only dead weight pressing on s is that of n, c c, and the glass diaphragm. [illustration: fig. .--perspective view of a phonograph recorder.] as the cylinder revolves, the recorder is shifted continuously along by a leading screw having one hundred or more threads to the inch cut on it, so that it traces a continuous helical groove from one end of the wax cylinder to the other. this groove is really a series of very minute indentations, not exceeding / th of an inch in depth.[ ] seen under a microscope, the surface of the record is a succession of hills and valleys, some much larger than others (fig. , _a_). a loud sound causes the stylus to give a vigorous dig, while low sounds scarcely move it at all. the wonderful thing about this sound-recording is, that not only are the fundamental tones of musical notes impressed, but also the harmonics, which enable us to decide at once whether the record is one of a cornet, violin, or banjo performance. furthermore, if several instruments are playing simultaneously near the recorder's horn, the stylus catches all the different shades of tone of every note of a chord. there are, so to speak, minor hills and valleys cut in the slopes of the main hills and valleys. [illustration: fig. .--section of the reproducer of an edison bell phonograph.] [illustration: fig. .--perspective view of a phonograph reproducer.] the _reproducer_ (fig. ) is somewhat more complicated than the recorder. as before, we have a circular box communicating with the horn of the instrument. a thin glass disc forms a bottom to the box. it is held in position between rubber rings, r r, by a screw collar, c. to the centre is attached a little eye, from which hangs a link, l. pivoted at p from one edge of the box is a _floating weight_, having a circular opening immediately under the eye. the link passes through this to the left end of a tiny lever, which rocks on a pivot projecting from the weight. to the right end of the lever is affixed a sapphire bar, or stylus, with a ball end of a diameter equal to that of the cutting point of the recorder. the floating weight presses the stylus against the record, and also keeps the link between the rocking lever of the glass diaphragm in a state of tension. every blow given to the stylus is therefore transmitted by the link to the diaphragm, which vibrates and sends an air-impulse into the horn. as the impulses are given at the same rate as those which agitated the diaphragm of the recorder, the sounds which they represent are accurately reproduced, even to the harmonics of a musical note. the gramophone. this effects the same purpose as the phonograph, but in a somewhat different manner. the phonograph recorder digs vertically downwards into the surface of the record, whereas the stylus of the gramophone wags from side to side and describes a snaky course (fig. _b_). it makes no difference in talking-machines whether the reproducing stylus be moved sideways or vertically by the record, provided that motion is imparted by it to the diaphragm. [illustration: fig. _a._] [illustration: fig. _b._] [illustration: fig. _c._--section of a gramophone reproducer.] in fig. _c_ the construction of the gramophone reproducer is shown in section. a is the cover which screws on to the bottom b, and confines the diaphragm d between itself and a rubber ring. the portion b is elongated into a tubular shape for connection with the horn, an arm of which slides over the tube and presses against the rubber ring c to make an air-tight joint. the needle-carrier n is attached at its upper end to the centre of the diaphragm. at a point indicated by the white dot a pin passes through it and the cover. the lower end is tubular to accommodate the steel points, which have to be replaced after passing once over a record. a screw, s, working in a socket projecting from the carrier, holds the point fast. the record moves horizontally under the point in a plane perpendicular to the page. the groove being zigzag, the needle vibrates right and left, and rotating the carrier a minute fraction of an inch on the pivot, shakes the glass diaphragm and sends waves of air into the horn. the gramophone is a reproducing instrument only. the records are made on a special machine, fitted with a device for causing the recorder point to describe a spiral course from the circumference to the centre of the record disc. some gramophone records have as many as turns to the inch. the total length of the tracing on a ten-inch "concert" record is about , feet. the making of records. for commercial purposes it would not pay to make every record separately in a recording machine. the expense of employing good singers and instrumentalists renders such a method impracticable. all the records we buy are made from moulds, the preparation of which we will now briefly describe. cylinder, or phonograph records. first of all, a wax record is made in the ordinary way on a recording machine. after being tested and approved, it is hung vertically and centrally from a rotating table pivoted on a vertical metal spike passing up through the record. on one side of the table is a piece of iron. on each side of the record, and a small distance away, rises a brass rod enclosed in a glass tube. the top of the rods are hooked, so that pieces of gold leaf may be suspended from them. a bell-glass is now placed over the record, table, and rods, and the air is sucked out by a pump. as soon as a good vacuum has been obtained, the current from the secondary circuit of an induction coil is sent into the rods supporting the gold leaves, which are volatilized by the current jumping from one to the other. a magnet, whirled outside the bell-glass, draws round the iron armature on the pivoted table, and consequently revolves the record, on the surface of which a very thin coating of gold is deposited. the record is next placed in an electroplating bath until a copper shell one-sixteenth of an inch thick has formed all over the outside. this is trued up on a lathe and encased in a brass tube. the "master," or original wax record, is removed by cooling it till it contracts sufficiently to fall out of the copper mould, on the inside surface of which are reproduced, in relief, the indentations of the wax "master." copies are made from the mould by immersing it in a tank of melted wax. the cold metal chills the wax that touches it, so that the mould soon has a thick waxen lining. the mould and copy are removed from the tank and mounted on a lathe, which shapes and smooths the inside of the record. the record is loosened from the mould by cooling. after inspection for flaws, it is, if found satisfactory, packed in cotton-wool and added to the saleable stock. gramophone master records are made on a circular disc of zinc, coated over with a very thin film of acid-proof fat. when the disc is revolved in the recording machine, the sharp stylus cuts through the fat and exposes the zinc beneath. on immersion in a bath of chromic acid the bared surfaces are bitten into, while the unexposed parts remain unaffected. when the etching is considered complete, the plate is carefully cleaned and tested. a negative copper copy is made from it by electrotyping. this constitutes the mould. from it as many as , copies may be made on ebonite plates by combined pressure and heating. [ ] the edison bell phonograph is here referred to. [ ] some of the sibilant or hissing sounds of the voice are computed to be represented by depressions less than a millionth of an inch in depth. yet these are reproduced very clearly! chapter xvii. why the wind blows. why the wind blows--land and sea breezes--light air and moisture--the barometer--the column barometer--the wheel barometer--a very simple barometer--the aneroid barometer--barometers and weather--the diving-bell--the diving-dress--air-pumps--pneumatic tyres--the air-gun--the self-closing door-stop--the action of wind on oblique surfaces--the balloon--the flying-machine. when a child's rubber ball gets slack through a slight leakage of air, and loses some of its bounce, it is a common practice to hold it for a few minutes in front of the fire till it becomes temporarily taut again. why does the heat have this effect on the ball? no more air has been forced into the ball. after perusing the chapter on the steam-engine the reader will be able to supply the answer. "because the molecules of air dash about more vigorously among one another when the air is heated, and by striking the inside of the ball with greater force put it in a state of greater tension." if we heat an open jar there is no pressure developed, since the air simply expands and flows out of the neck. but the air that remains in the jar, being less in quantity than when it was not yet heated, weighs less, though occupying the same space as before. if we took a very thin bladder and filled it with hot air it would therefore float in colder air, proving that heated air, as we should expect, _tends to rise_. the fire-balloon employs this principle, the air inside the bag being kept artificially warm by a fire burning in some vessel attached below the open neck of the bag. now, the sun shines with different degrees of heating power at different parts of the world. where its effect is greatest the air there is hottest. we will suppose, for the sake of argument, that, at a certain moment, the air envelope all round the globe is of equal temperature. suddenly the sun shines out and heats the air at a point, a, till it is many degrees warmer than the surrounding air. the heated air expands, rises, and spreads out above the cold air. but, as a given depth of warm air has less weight than an equal depth of cold air, the cold air at once begins to rush towards b and squeeze the rest of the warm air out. we may therefore picture the atmosphere as made up of a number of colder currents passing along the surface of the earth to replace warm currents rising and spreading over the upper surface of the cold air. a similar circulation takes place in a vessel of heated water (see p. ). land and sea breezes. a breeze which blows from the sea on to the land during the day often reverses its direction during the evening. why is this? the earth grows hot or cold more rapidly than the sea. when the sun shines hotly, the land warms quickly and heats the air over it, which becomes light, and is displaced by the cooler air over the sea. when the sun sets, the earth and the air over it lose their warmth quickly, while the sea remains at practically the same temperature as before. so the balance is changed, the heavier air now lying over the land. it therefore flows seawards, and drives out the warmer air there. light air and moisture. light, warm air absorbs moisture. as it cools, the moisture in it condenses. breathe on a plate, and you notice that a watery film forms on it at once. the cold surface condenses the water suspended in the warm breath. if you wish to dry a damp room you heat it. moisture then passes from the walls and objects in the room to the atmosphere. the barometer. this property of air is responsible for the changes in weather. light, moisture-laden air meets cold, dry air, and the sudden cooling forces it to release its moisture, which falls as rain, or floats about as clouds. if only we are able to detect the presence of warm air-strata above us, we ought to be in a position to foretell the weather. we can judge of the specific gravity of the air in our neighbourhood by means of the barometer, which means "weight-measurer." the normal air-pressure at sea-level on our bodies or any other objects is about lbs. to the square inch--that is to say, if you could imprison and weigh a column of air one inch square in section and of the height of the world's atmospheric envelope, the scale would register lbs. many years ago ( ) torricelli, a pupil of galileo, first calculated the pressure by a very simple experiment. he took a long glass tube sealed at one end, filled it with mercury, and, closing the open end with the thumb, inverted the tube and plunged the open end below the surface of a tank of mercury. on removing his thumb he found that the mercury sank in the tube till the surface of the mercury in the tube was about inches in a vertical direction above the surface of the mercury in the tank. now, as the upper end was sealed, there must be a vacuum _above_ the mercury. what supported the column? the atmosphere. so it was evident that the downward pressure of the mercury exactly counterbalanced the upward pressure of the air. as a mercury column inches high and inch square weighs lbs., the air-pressure on a square inch obviously is the same. [illustration: fig. .--a fortin barometer.] fortin's column barometer is a simple torricellian tube, t, with the lower end submerged in a little glass tank of mercury (fig. ). the bottom of this tank is made of washleather. to obtain a "reading" the screw s, pressing on the washleather, is adjusted until the mercury in the tank rises to the tip of the little ivory point p. the reading is the figure of the scale on the face of the case opposite which the surface of the column stands. [illustration: fig. .] the wheel barometer also employs the mercury column (fig. ). the lower end of the tube is turned up and expanded to form a tank, c. the pointer p, which travels round a graduated dial, is mounted on a spindle carrying a pulley, over which passes a string with a weight at each end. the heavier of the weights rests on the top of the mercury. when the atmospheric pressure falls, the mercury in c rises, lifting this weight, and the pointer moves. this form of barometer is not so delicate or reliable as fortin's, or as the siphon barometer, which has a tube of the same shape as the wheel instrument, but of the same diameter from end to end except for a contraction at the bend. the reading of a siphon is the distance between the two surfaces of the mercury. a very simple barometer is made by knocking off the neck of a small bottle, filling the body with water, and hanging it up by a string in the position shown (fig. ). when the atmospheric pressure falls, the water at the orifice bulges outwards; when it rises, the water retreats till its surface is slightly concave. [illustration: fig. .] the aneroid barometer. on account of their size and weight, and the comparative difficulty of transporting them without derangement of the mercury column, column barometers are not so generally used as the aneroid variety. aneroid means "without moisture," and in this particular connection signifies that no liquid is used in the construction of the barometer. fig. shows an aneroid in detail. the most noticeable feature is the vacuum chamber, v c, a circular box which has a top and bottom of corrugated but thin and elastic metal. sections of the box are shown in figs. , . it is attached at the bottom to the base board of the instrument by a screw (fig. ). from the top rises a pin, p, with a transverse hole through it to accommodate the pin k e, which has a triangular section, and stands on one edge. [illustration: fig. .--an aneroid barometer.] returning to fig. , we see that p projects through s, a powerful spring of sheet-steel. to this is attached a long arm, c, the free end of which moves a link rotating, through the pin e, a spindle mounted in a frame, d. the spindle moves arm f. this pulls on a very minute chain wound round the pointer spindle b, in opposition to a hairspring, h s. b is mounted on arm h, which is quite independent of the rest of the aneroid. [illustration: fig. . fig. . the vacuum chamber of an aneroid barometer extended and compressed.] the vacuum chamber is exhausted during manufacture and sealed. it would naturally assume the shape of fig. , but the spring s, acting against the atmospheric pressure, pulls it out. as the pressure varies, so does the spring rise or sink; and the slightest movement is transmitted through the multiplying arms c, e, f, to the pointer. a good aneroid is so delicate that it will register the difference in pressure caused by raising it from the floor to the table, where it has a couple of feet less of air-column resting upon it. an aneroid is therefore a valuable help to mountaineers for determining their altitude above sea-level. barometers and weather. we may now return to the consideration of forecasting the weather by movements of the barometer. the first thing to keep in mind is, that the instrument is essentially a _weight_ recorder. how is weather connected with atmospheric weight? in england the warm south-west wind generally brings wet weather, the north and east winds fine weather; the reason for this being that the first reaches us after passing over the atlantic and picking up a quantity of moisture, while the second and third have come overland and deposited their moisture before reaching us. a sinking of the barometer heralds the approach of heated air--that is, moist air--which on meeting colder air sheds its moisture. so when the mercury falls we expect rain. on the other hand, when the "glass" rises, we know that colder air is coming, and as colder air comes from a dry quarter we anticipate fine weather. it does not follow that the same conditions are found in all parts of the world. in regions which have the ocean to the east or the north, the winds blowing thence would be the rainy winds, while south-westerly winds might bring hot and dry weather. the diving-bell. water is nearly times as heavy as air. if we submerge a barometer a very little way below the surface of a water tank, we shall at once observe a rise of the mercury column. at a depth of feet the pressure on any submerged object is lbs. to the square inch, in addition to the atmospheric pressure of lbs. per square inch--that is, there would be a -lb. _absolute_ pressure. as a rule, when speaking of hydraulic pressures, we start with the normal atmospheric pressure as zero, and we will here observe the practice. [illustration: fig. .--a diving bell.] the diving-bell is used to enable people to work under water without having recourse to the diving-dress. a sketch of an ordinary diving-bell is given in fig. . it may be described as a square iron box without a bottom. at the top are links by which it is attached to a lowering chain, and windows, protected by grids; also a nozzle for the air-tube. [illustration: fig. .] a simple model bell (fig. ) is easily made out of a glass tumbler which has had a tap fitted in a hole drilled through the bottom. we turn off the tap and plunge the glass into a vessel of water. the water rises a certain way up the interior, until the air within has been compressed to a pressure equal to that of the water at the level of the surface inside. the further the tumbler is lowered, the higher does the water rise inside it. evidently men could not work in a diving-bell which is invaded thus by water. it is imperative to keep the water at bay. this we can do by attaching a tube to the tap (fig. ) and blowing into the tumbler till the air-pressure exceeds that of the water, which is shown by bubbles rising to the surface. the diving-bell therefore has attached to it a hose through which air is forced by pumps from the atmosphere above, at a pressure sufficient to keep the water out of the bell. this pumping of air also maintains a fresh supply of oxygen for the workers. [illustration: fig. .] inside the bell is tackle for grappling any object that has to be moved, such as a heavy stone block. the diving-bell is used mostly for laying submarine masonry. "the bell, slung either from a crane on the masonry already built above sea-level, or from a specially fitted barge, comes into action. the block is lowered by its own crane on to the bottom. the bell descends upon it, and the crew seize it with tackle suspended inside the bell. instructions are sent up as to the direction in which the bell should be moved with its burden, and as soon as the exact spot has been reached the signal for lowering is given, and the stone settles on to the cement laid ready for it."[ ] for many purposes it is necessary that the worker should have more freedom of action than is possible when he is cooped up inside an iron box. hence the invention of the diving-dress, which consists of two main parts, the helmet and the dress proper. the helmet (fig. ) is made of copper. a breastplate, b, shaped to fit the shoulders, has at the neck a segmental screw bayonet-joint. the headpiece is fitted with a corresponding screw, which can be attached or removed by one-eighth of a turn. the neck edge of the dress, which is made in one piece, legs, arms, body and all, is attached to the breastplate by means of the plate p^ , screwed down tightly on it by the wing-nuts n n, the bolts of which pass through the breastplate. air enters the helmet through a valve situated at the back, and is led through tubes along the inside to the front. this valve closes automatically if any accident cuts off the air supply, and encloses sufficient air in the dress to allow the diver to regain the surface. the outlet valve o v can be adjusted by the diver to maintain any pressure. at the sides of the headpiece are two hooks, h, over which pass the cords connecting the heavy lead weights of lbs. each hanging on the diver's breast and back. these weights are also attached to the knobs k k. a pair of boots, having lbs. of lead each in the soles, complete the dress. three glazed windows are placed in the headpiece, that in the front, r w, being removable, so that the diver may gain free access to the air when he is above water without being obliged to take off the helmet. [illustration: fig. .--a diver's helmet.] by means of telephone wires built into the life-line (which passes under the diver's arms and is used for lowering and hoisting) easy communication is established between the diver and his attendants above. the transmitter of the telephone is placed inside the helmet between the front and a side window, the receiver and the button of an electric bell in the crown. this last he can press by raising his head. the life-line sometimes also includes the wires for an electric lamp (fig. ) used by the diver at depths to which daylight cannot penetrate. the pressure on a diver's body increases in the ratio of - / lbs. per square inch for every feet that he descends. the ordinary working limit is about feet, though "old hands" are able to stand greater pressures. the record is held by one james hooper, who, when removing the cargo of the _cape horn_ sunk off the south american coast, made seven descents of feet, one of which lasted for forty-two minutes. [illustration: fig. .--diver's electric lamp.] a sketch is given (fig. ) of divers working below water with pneumatic tools, fed from above with high-pressure air. owing to his buoyancy a diver has little depressing or pushing power, and he cannot bore a hole in a post with an auger unless he is able to rest his back against some firm object, or is roped to the post. pneumatic chipping tools merely require holding to their work, their weight offering sufficient resistance to the very rapid blows which they make. [illustration: fig. .--divers at work below water with pneumatic tools.] air-pumps. [illustration: fig. .] [illustration: fig. .] mention having been made of the air-pump, we append diagrams (figs. , ) of the simplest form of air-pump, the cycle tyre inflator. the piston is composed of two circular plates of smaller diameter than the barrel, holding between them a cup leather. during the upstroke the cup collapses inwards and allows air to pass by it. on the downstroke (fig. ) the edges of the cup expand against the barrel, preventing the passage of air round the piston. a double-action air-pump requires a long, well-fitting piston with a cup on each side of it, and the addition of extra valves to the barrel, as the cups under these circumstances cannot act as valves. pneumatic tyres. [illustration: fig. .] [illustration: fig. .] the action of the pneumatic tyre in reducing vibration and increasing the speed of a vehicle is explained by figs. , . when the tyre encounters an obstacle, such as a large stone, it laps over it (fig. ), and while supporting the weight on the wheel, reduces the deflection of the direction of movement. when an iron-tyred wheel meets a similar obstacle it has to rise right over it, often jumping a considerable distance into the air. the resultant motions of the wheel are indicated in each case by an arrow. every change of direction means a loss of forward velocity, the loss increasing with the violence and extent of the change. the pneumatic tyre also scores because, on account of its elasticity, it gives a "kick off" against the obstacle, which compensates for the resistance during compression. [illustration: fig. .--section of the mechanism of an air-gun.] the air-gun. this may be described as a valveless air-pump. fig. is a section of a "gem" air-gun, with the mechanism set ready for firing. in the stock of the gun is the _cylinder_, in which an accurately fitting and hollow _piston_ moves. a powerful helical spring, turned out of a solid bar of steel, is compressed between the inside end of the piston and the upper end of the butt. to set the gun, the _catch_ is pressed down so that its hooked end disengages from the stock, and the barrel is bent downwards on pivot p. this slides the lower end of the _compressing lever_ towards the butt, and a projection on the guide b, working in a groove, takes the piston with it. when the spring has been fully compressed, the triangular tip of the rocking cam r engages with a groove in the piston's head, and prevents recoil when the barrel is returned to its original position. on pulling the trigger, the piston is released and flies up the cylinder with great force, and the air in the cylinder is compressed and driven through the bore of the barrel, blocked by the leaden slug, to which the whole energy of the expanding spring is transmitted through the elastic medium of the air. there are several other good types of air-gun, all of which employ the principles described above. the self-closing door-stop is another interesting pneumatic device. it consists of a cylinder with an air-tight piston, and a piston rod working through a cover at one end. the other end of the cylinder is pivoted to the door frame. when the door is opened the piston compresses a spring in the cylinder, and air is admitted past a cup leather on the piston to the upper part of the cylinder. this air is confined by the cup leather when the door is released, and escapes slowly through a leak, allowing the spring to regain its shape slowly, and by the agency of the piston rod to close the door. the action of wind on oblique surfaces. why does a kite rise? why does a boat sail across the wind? we can supply an answer almost instinctively in both cases, "because the wind pushes the kite or sail aside." it will, however, be worth while to look for a more scientific answer. the kite cannot travel in the direction of the wind because it is confined by a string. but the face is so attached to the string that it inclines at an angle to the direction of the wind. now, when a force meets an inclined surface which it cannot carry along with it, but which is free to travel in another direction, the force may be regarded as resolving itself into _two_ forces, coming from each side of the original line. these are called the _component_ forces. [illustration: fig. .] to explain this we give a simple sketch of a kite in the act of flying (fig. ). the wind is blowing in the direction of the solid arrow a. the oblique surface of the kite resolves its force into the two components indicated by the dotted arrows b and c. of these c only has lifting power to overcome the force of gravity. the kite assumes a position in which force c and gravity counterbalance one another. [illustration: fig. .] a boat sailing across the wind is acted on in a similar manner (fig. ). the wind strikes the sail obliquely, and would thrust it to leeward were it not for the opposition of the water. the force a is resolved into forces b and c, of which c propels the boat on the line of its axis. the boat can be made to sail even "up" the wind, her head being brought round until a point is reached at which the force b on the boat, masts, etc., overcomes the force c. the capability of a boat for sailing up wind depends on her "lines" and the amount of surface she offers to the wind. the balloon is a pear-shaped bag--usually made of silk--filled with some gas lighter than air. the tendency of a heavier medium to displace a lighter drives the gas upwards, and with it the bag and the wicker-work car attached to a network encasing the bag. the tapering neck at the lower end is open, to permit the free escape of gas as the atmospheric pressure outside diminishes with increasing elevation. at the top of the bag is a wooden valve opening inwards, which can be drawn down by a rope passing up to it through the neck whenever the aeronaut wishes to let gas escape for a descent. he is able to cause a very rapid escape by pulling another cord depending from a "ripping piece" near the top of the bag. in case of emergency this is torn away bodily, leaving a large hole. the ballast (usually sand) carried enables him to maintain a state of equilibrium between the upward pull of the gas and the downward pull of gravity. to sink he lets out gas, to rise he throws out ballast; and this process can be repeated until the ballast is exhausted. the greatest height ever attained by aeronauts is the - / miles, or , feet, of messrs. glaisher and coxwell on september , . the ascent nearly cost them their lives, for at an elevation of about , feet they were partly paralyzed by the rarefaction of the air, and had not mr. coxwell been able to pull the valve rope with his teeth and cause a descent, both would have died from want of air. [illustration: fig. .] the _flying-machine_, which scientific engineers have so long been trying to produce, will probably be quite independent of balloons, and will depend for its ascensive powers on the action of air on oblique surfaces. sir hiram maxim's experimental air-ship embodied the principles shown by fig. . on a deck was mounted an engine, e, extremely powerful for its weight. this drove large propellers, s s. large aeroplanes, of canvas stretched over light frameworks, were set up overhead, the forward end somewhat higher than the rear. the machine was run on rails so arranged as to prevent it rising. unfortunately an accident happened at the first trial and destroyed the machine. in actual flight it would be necessary to have a vertical rudder for altering the horizontal direction, and a horizontal "tail" for steering up or down. the principle of an aeroplane is that of the kite, with this difference, that, instead of moving air striking a captive body, a moving body is propelled against more or less stationary air. the resolution of forces is shown by the arrows as before. up to the present time no practical flying-machine has appeared. but experimenters are hard at work examining the conditions which must be fulfilled to enable man to claim the "dominion of the air." [ ] the "romance of modern mechanism," p. chapter xviii. hydraulic machinery. the siphon--the bucket pump--the force-pump--the most marvellous pump--the blood channels--the course of the blood--the hydraulic press--household water-supply fittings--the ball-cock--the water-meter--water-supply systems--the household filter--gas traps--water engines--the cream separator--the "hydro." in the last chapter we saw that the pressure of the atmosphere is lbs. to the square inch. suppose that to a very long tube having a sectional area of one square inch we fit an air-tight piston (fig. ), and place the lower end of the tube in a vessel of water. on raising the piston a vacuum would be created in the tube, did not the pressure of the atmosphere force water up into the tube behind the piston. the water would continue to rise until it reached a point feet perpendicularly above the level of the water in the vessel. the column would then weigh lbs., and exactly counterbalance the atmospheric pressure; so that a further raising of the piston would not raise the water any farther. at sea-level, therefore, the _lifting_ power of a pump by suction is limited to feet. on the top of a lofty mountain, where the air-pressure is less, the height of the column would be diminished--in fact, be proportional to the pressure. [illustration: fig. .] [illustration: fig. .] the siphon is an interesting application of the principle of suction. by its own weight water may be made to lift water through a height not exceeding feet. this is explained by fig. . the siphon pipe, a b c d, is in the first instance filled by suction. the weight of the water between a and b counter-balances that between b and c. but the column c d hangs, as it were, to the heels of b c, and draws it down. or, to put it otherwise, the column b d, being heavier than the column b a, draws it over the topmost point of the siphon. any parting between the columns, provided that b a does not exceed feet, is impossible, as the pressure of the atmosphere on the mouth of b a is sufficient to prevent the formation of a vacuum. the bucket pump. we may now pass to the commonest form of pump used in houses, stables, gardens, etc. (fig. ). the piston has a large hole through it, over the top of which a valve is hinged. at the bottom of the barrel is a second valve, also opening upwards, seated on the top of the supply pipe. in sketch (_a_) the first upstroke is in progress. a vacuum forms under the piston, or plunger, and water rises up the barrel to fill it. the next diagram (_b_) shows the first downstroke. the plunger valve now opens and allows water to rise above the piston, while the lower closes under the pressure of the water above and the pull of that below. during the second upstroke (_c_) the water above the piston is raised until it overflows through the spout, while a fresh supply is being sucked in below. [illustration: fig. .] the force-pump. [illustration: fig. . force-pump; suction stroke.] [illustration: fig. . force-pump; delivery stroke.] for driving water to levels above that of the pump a somewhat different arrangement is required. one type of force-pump is shown in figs. , . the piston now is solid, and the upper valve is situated in the delivery pipe. during an upstroke this closes, and the other opens; the reverse happening during a downstroke. an air-chamber is generally fitted to the delivery pipe when water is to be lifted to great heights or under high pressure. at each delivery stroke the air in the chamber is compressed, absorbing some of the shock given to the water in the pipe by the water coming from the pump; and its expansion during the next suction stroke forces the water gradually up the pipe. the air-chamber is a very prominent feature of the fire-engine. a _double-action_ force-pump is seen in fig. , making an upward stroke. both sides of the piston are here utilized, and the piston rod works through a water-tight stuffing-box. the action of the pump will be easily understood from the diagram. [illustration: fig. .] the most marvellous pump known is the _heart_. we give in fig. a diagrammatic sketch of the system of blood circulation in the human body, showing the heart, the arteries, and the veins, big and little. the body is supposed to be facing the reader, so that the left lung, etc., is to his right. [illustration: fig. .--a diagrammatic representation of the circulatory system of the blood.] the heart, which forces the blood through the body, is a large muscle (of about the size of the clenched fist) with four cavities. these are respectively known as the right and left _auricles_, and the right and left _ventricles_. they are arranged in two pairs, the auricle uppermost, separated by a fleshy partition. between each auricle and its ventricle is a valve, which consists of strong membranous flaps, with loose edges turned downwards. the left-side valve is the _mitral_ valve, that between the right auricle and ventricle the _tricuspid_ valve. the edges of the valves fall together when the heart contracts, and prevent the passage of blood. each ventricle has a second valve through which it ejects the blood. (that of the right ventricle has been shown double for the sake of convenience.) the action of the heart is this:--the auricles and ventricles expand; blood rushes into the auricles from the channels supplying them, and distends them and the ventricles; the auricles contract and fill the ventricles below quite full (there are no valves above the auricles, but the force of contraction is not sufficient to return the blood to the veins); the ventricles contract; the mitral and tricuspid valves close; the valves leading to the arteries open; blood is forced out of the ventricles. the blood channels are of two kinds--( ) the _arteries_, which lead the blood into the circulatory system; ( ) the _veins_, which lead the blood back to the heart. the arteries divide up into branches, and these again divide into smaller and smaller arteries. the smallest, termed _capillaries_ (latin, _capillus_, a hair), are minute tubes having an average diameter of / th of an inch. these permeate every part of the body. the capillary arteries lead into the smallest veins, which unite to form larger and larger veins, until what we may call the main streams are reached. through these the blood flows to the heart. there are three main points of difference between arteries and veins. in the first place, the larger arteries have thick elastic walls, and maintain their shape even when empty. this elasticity performs the function of the air-chamber of the force-pump. when the ventricles contract, driving blood into the arteries, the walls of the latter expand, and their contraction pushes the blood steadily forward without shock. the capillaries have very thin walls, so that fluids pass through them to and from the body, feeding it and taking out waste matter. the veins are all thin-walled, and collapse when empty. secondly, most veins are furnished with valves, which prevent blood flowing the wrong way. these are similar in principle to those of the heart. arteries have no valves. thirdly, arteries are generally deeply set, while many of the veins run near the surface of the body. those on the front of the arm are specially visible. place your thumb on them and run it along towards the wrist, and you will notice that the veins distend owing to the closing of the valves just mentioned. arterial blood is _red_, and comes out from a cut in gulps, on account of the contraction of the elastic walls. if you cut a vein, _blue_ blood issues in a steady stream. the change of colour is caused by the loss of oxygen during the passage of the blood through the capillaries, and the absorption of carbon dioxide from the tissues. the _lungs_ are two of the great purifiers of the blood. as it circulates through them, it gives up the carbon dioxide which it has absorbed, and receives pure oxygen in exchange. if the air of a room is "foul," the blood does not get the proper amount of oxygen. for this reason it is advisable for us to keep the windows of our rooms open as much as possible both day and night. fatigue is caused by the accumulation of carbon dioxide and other impurities in the blood. when we run, the heart pumps blood through the lungs faster than they can purify it, and eventually our muscles become poisoned to such an extent that we have to stop from sheer exhaustion. the course of the blood. it takes rather less than a minute for a drop of blood to circulate from the heart through the whole system and back to the heart. we may briefly summarize the course of the circulation of the blood thus:--it is expelled from the left ventricle into the _aorta_ and the main arteries, whence it passes into the smaller arteries, and thence into the capillaries of the brain, stomach, kidneys, etc. it here imparts oxygen to the body, and takes in impurities. it then enters the veins, and through them flows back to the right auricle; is driven into the right ventricle; is expelled into the _pulmonary_ (lung) _arteries_; enters the lungs, and is purified. it returns to the left auricle through the _pulmonary veins_; enters the left auricle, passes to left ventricle, and so on. a healthy heart beats from times per minute in a one-year-old infant to per minute in a very aged person. the normal rate for a middle-aged adult is from to beats. heart disease signifies the failure of the heart valves to close properly. blood passes back when the heart contracts, and the circulation is much enfeebled. by listening through a stethoscope the doctor is able to tell whether the valves are in good order. a hissing sound during the beat indicates a leakage past the valves; a thump, or "clack," that they shut completely. the hydraulic press. it is a characteristic of fluids and gases that if pressure be brought to bear on any part of a mass of either class of bodies it is transmitted equally and undiminished in all directions, and acts with the same force on all equal surfaces, at right angles to those surfaces. the great natural philosopher pascal first formulated this remarkable fact, of which a simple illustration is given in fig. . two cylinders, a and b, having a bore of one and two inches respectively, are connected by a pipe. water is poured in, and pistons fitting the cylinders accurately and of equal weight are inserted. on piston b is placed a load of lbs. to prevent a rising above the level of b, it must be loaded proportionately. the area of piston a is four times that of b, so that if we lay on it a -lb. weight, neither piston will move. the walls of the cylinders and connecting pipe are also pressed outwards in the ratio of lbs. for every part of their interior surface which has an area equal to that of piston b. [illustration: fig. .] [illustration: fig. .--the cylinder and ram of a hydraulic press.] the hydraulic press is an application of this law. cylinder b is represented by a force pump of small bore, capable of delivering water at very high pressures (up to tons per square inch). in the place of a we have a stout cylinder with a solid plunger, p (fig. ), carrying the _table_ on which the object to be pressed is placed. bramah, the inventor of the hydraulic press, experienced great difficulty in preventing the escape of water between the top of the cylinder and the plunger. if a "gland" packing of the type found in steam-cylinders were used, it failed to hold back the water unless it were screwed down so tightly as to jam the plunger. he tried all kinds of expedients without success; and his invention, excellent though it was in principle, seemed doomed to failure, when his foreman, henry maudslay,[ ] solved the problem in a simple but most masterly manner. he had a recess turned in the neck of the cylinder at the point formerly occupied by the stuffing-box, and into this a leather collar of u-section (marked solid black in fig. ) was placed with its open side downwards. when water reached it, it forced the edges apart, one against the plunger, the other against the walls of the recess, with a degree of tightness proportionate to the pressure. on water being released from the cylinder the collar collapsed, allowing the plunger to sink without friction. the principle of the hydraulic press is employed in lifts; in machines for bending, drilling, and riveting steel plates, or forcing wheels on or off their axles; for advancing the "boring shield" of a tunnel; and for other purposes too numerous to mention. household water-supply fittings. among these, the most used is the tap, or cock. when a house is served by the town or district water supply, the fitting of proper taps on all pipes connected with the supply is stipulated for by the water-works authorities. the old-fashioned "plug" tap is unsuitable for controlling high-pressure water on account of the suddenness with which it checks the flow. lest the reader should have doubts as to the nature of a plug tap, we may add that it has a tapering cone of metal working in a tapering socket. on the cone being turned till a hole through it is brought into line with the channel of the tap, water passes. a quarter turn closes the tap. [illustration: fig. .--a screw-down water cock.] its place has been taken by the screw-down cock. a very common and effective pattern is shown in fig. . the valve v, with a facing of rubber, leather, or some other sufficiently elastic substance, is attached to a pin, c, which projects upwards into the spindle a of the tap. this spindle has a screw thread on it engaging with a collar, b. when the spindle is turned it rises or falls, allowing the valve to leave its seating, v s, or forcing it down on to it. a packing p in the neck of b prevents the passage of water round the spindle. to open or close the tap completely is a matter of several turns, which cannot be made fast enough to produce a "water-hammer" in the pipes by suddenly arresting the flow. the reader will easily understand that if water flowing at the rate of several miles an hour is abruptly checked, the shock to the pipes carrying it must be very severe. the ball-cock is used to feed a cistern automatically with water, and prevent the water rising too far in the cistern (fig. ). water enters the cistern through a valve, which is opened and closed by a plug faced with rubber. the lower extremity of the plug is flattened, and has a rectangular hole cut in it. through this passes a lever, l, attached at one end to a hollow copper sphere, and pivoted at the other on the valve casing. this casing is not quite circular in section, for two slots are cast in the circumference to allow water to pass round the plug freely when the valve is open. the buoyancy of the copper sphere is sufficient to force the plug's face up towards its seating as the valve rises, and to cut off the supply entirely when a certain level has been attained. if water is drawn off, the sphere sinks, the valve opens, and the loss is made good. [illustration: fig. .--an automatic ball-valve.] the water-meter. [illustration: fig. .] some consumers pay a sum quarterly for the privilege of a water supply, and the water company allows them to use as much as they require. others, however, prefer to pay a fixed amount for every thousand gallons used. in such cases, a water-meter is required to record the consumption. we append a sectional diagram of kennedy's patent water-meter (fig. ), very widely used. at the bottom is the measuring cylinder, fitted with a piston, ( ), which is made to move perfectly water-tight and free from friction by means of a cylindrical ring of india-rubber, rolling between the body of the piston and the internal surface of the cylinder. the piston rod ( ), after passing through a stuffing-box in the cylinder cover, is attached to a rack, ( ), which gears with a cog, ( ), fixed on a shaft. as the piston moves up and down, this cog is turned first in one direction, then in the other. to this shaft is connected the index mechanism (to the right). the cock-key ( ) is so constructed that it can put either end of the measuring cylinder in communication with the supply or delivery pipes, if given a quarter turn (see fig. ). the weighted lever ( ) moves loosely on the pinion shaft through part of a circle. from the pinion project two arms, one on each side of the lever. when the lever has been lifted by one of these past the vertical position, it falls by its own weight on to a buffer-box rest, ( ). in doing so, it strikes a projection on the duplex lever ( ), which is joined to the cock-key, and gives the latter a quarter turn. in order to follow the working of the meter, we must keep an eye on figs. and simultaneously. water is entering from a, the supply pipe. it flows through the cock downwards through channel d into the lower half of the cylinder. the piston rises, driving out the water above it through c to the delivery pipe b. just as the piston completes its stroke the weight, raised by the rack and pinion, topples over, and strikes the key-arm, which it sends down till stopped by the buffer-box. the tap is then at right angles to the position shown in fig. , and water is directed from a down c into the top of the cylinder, forcing the piston down, while the water admitted below during the last stroke is forced up the passage d, and out by the outlet b. before the piston has arrived at the bottom of the cylinder, the lifter will have lifted the weighted lever from the buffer-box, and raised it to a vertical position; from there it will have fallen on the right-hand key-arm, and have brought the cock-key to its former position, ready to begin another upward stroke. [illustration: fig. .] the _index mechanism_ makes allowance for the fact that the bevel-wheel on the pinion shaft has its direction reversed at the beginning of every stroke of the piston. this bevel engages with two others mounted loosely on the little shaft, on which is turned a screw thread to revolve the index counter wheels. each of these latter bevels actuates the shaft through a ratchet; but while one turns the shaft when rotating in a clockwise direction only, the other engages it when making an anti-clockwise revolution. the result is that the shaft is always turned in the same direction. water-supply systems. the water for a town or a district supply is got either from wells or from a river. in the former case it may be assumed to be free from impurities. in the latter, there is need for removing all the objectionable and dangerous matter which river water always contains in a greater or less degree. this purification is accomplished by first leading the water into large _settling tanks_, where the suspended matter sinks to the bottom. the water is then drawn off into _filtration beds_, made in the following manner. the bottom is covered with a thick layer of concrete. on this are laid parallel rows of bricks, the rows a small distance apart. then come a layer of bricks or tiles placed close together; a layer of coarse gravel; a layer of finer gravel; and a thick layer of sand at the top. the sand arrests any solid matter in the water as it percolates to the gravel and drains below. even the microbes,[ ] of microscopic size, are arrested as soon as the film of mud has formed on the top of the sand. until this film is formed the filter is not in its most efficient condition. every now and then the bed is drained, the surface mud and sand carefully drained off, and fresh sand put in their place. a good filter bed should not pass more than from two to three gallons per hour for every square foot of surface, and it must therefore have a large area. it is sometimes necessary to send the water through a succession of beds, arranged in terraces, before it is sufficiently pure for drinking purposes. the household filter. when there is any doubt as to the wholesomeness of the water supply, a small filter is often used. the microbe-stopper is usually either charcoal, sand, asbestos, or baked clay of some kind. in fig. we give a section of a maignen filter. r is the reservoir for the filtered water; a the filter case proper; d a conical perforated frame; b a jacket of asbestos cloth secured top and bottom by asbestos cords to d; c powdered carbon, between which and the asbestos is a layer of special chemical filtering medium. a perforated cap, e, covers in the carbon and prevents it being disturbed when water is poured in. the carbon arrests the coarser forms of matter; the asbestos the finer. the asbestos jacket is easily removed and cleansed by heating over a fire. [illustration: fig. .] the most useful form of household filter is one which can be attached to a tap connected with the main. such a filter is usually made of porcelain or biscuit china. the berkefeld filter has an outer case of iron, and an interior hollow "candle" of porcelain from which a tube passes through the lid of the filter to a storage tank for the filtered water. the water from the main enters the outer case, and percolates through the porcelain walls to the internal cavity and thence flows away through the delivery pipe. whatever be the type of filter used it must be cleansed at proper intervals. a foul filter is very dangerous to those who drink the water from it. it has been proved by tests that, so far from purifying the water, an inefficient and contaminated filter passes out water much more highly charged with microbes than it was before it entered. we must not therefore think that, because water has been filtered, it is necessarily safe. the reverse is only too often the case. gas traps. dangerous microbes can be breathed as well as drunk into the human system. every communication between house and drains should be most carefully "trapped." the principle of a gas trap between, say, a kitchen sink and the drain to carry off the water is given in fig. . enough water always remains in the bend to rise above the level of the elbow, effectually keeping back any gas that there may be in the pipe beyond the bend. [illustration: fig. .--a trap for foul air.] water-engines. before the invention of the steam-engine human industries were largely dependent on the motive power of the wind and running water. but when the infant nursed by watt and stephenson had grown into a giant, both of these natural agents were deposed from the important position they once held. windmills in a state of decay crown many of our hilltops, and the water-wheel which formerly brought wealth to the miller now rots in its mountings at the end of the dam. except for pumping and moving boats and ships, wind-power finds its occupation gone. it is too uncertain in quantity and quality to find a place in modern economics. water-power, on the other hand, has received a fresh lease of life through the invention of machinery so scientifically designed as to use much more of the water's energy than was possible with the old-fashioned wheel. [illustration: fig. .--a pelton wheel which develops , horse-power. observe the shape of the double buckets.] the _turbine_, of which we have already spoken in our third chapter, is now the favourite hydraulic engine. some water-turbines work on much the same principle as the parsons steam-turbine; others resemble the de laval. among the latter the pelton wheel takes the first place. by the courtesy of the manufacturers we are able to give some interesting details and illustrations of this device. [illustration: fig. .--pelton wheel mounted, with nozzle in position.] the wheel, which may be of any diameter from six inches to ten feet, has buckets set at regular intervals round the circumference, sticking outwards. each bucket, as will be gathered from our illustration of an enormous , h.p. wheel (fig. ), is composed of two cups. a nozzle is so arranged as to direct water on the buckets just as they reach the lowest point of a revolution (see fig. ). the water strikes the bucket on the partition between the two cups, which turns it right and left round the inside of the cups. the change of direction transfers the energy of the water to the wheel. [illustration: fig. .--speed regulator for pelton wheel.] the speed of the wheel may be automatically regulated by a deflecting nozzle (fig. ), which has a ball and socket joint to permit of its being raised or lowered by a centrifugal governor, thus throwing the stream on or off the buckets. the power of the wheel is consequently increased or diminished to meet the change of load, and a constant speed is maintained. when it is necessary to waste as little water as possible, a concentric tapered needle may be fitted inside the nozzle. when the nozzle is in its highest position the needle tip is withdrawn; as the nozzle sinks the needle protrudes, gradually decreasing the discharge area of the nozzle. pelton wheels are designed to run at all speeds and to use water of any pressure. at manitou, colorado, is an installation of three wheels operated by water which leaves the nozzle at the enormous pressure of lbs. per square inch. it is interesting to note that jets of very high-pressure water offer astonishing resistance to any attempt to deflect their course. a three-inch jet of -lb. water cannot be cut through by a blow from a crowbar. in order to get sufficient pressure for working hydraulic machinery in mines, factories, etc., water is often led for many miles in flumes, or artificial channels, along the sides of valleys from the source of supply to the point at which it is to be used. by the time that point is reached the difference between the gradients of the flume and of the valley bottom has produced a difference in height of some hundreds of feet. [illustration: fig. .--the laxey water-wheel, isle of man. in the top right-hand corner is a pelton wheel of proportionate size required to do the same amount of work with the same consumption of water at the same pressure.] the full-page illustration on p. affords a striking testimony to the wonderful progress made in engineering practice during the last fifty years. the huge water-wheel which forms the bulk of the picture is that at laxey, in the isle of man. it is - / feet in diameter, and is supposed to develop horse-power, which is transmitted several hundreds of feet by means of wooden rods supported at regular intervals. the power thus transmitted operates a system of pumps in a lead mine, raising gallons of water per minute, to an elevation of , feet. the driving water is brought some distance to the wheel in an underground conduit, and is carried up the masonry tower by pressure, flowing over the top into the buckets on the circumference of the wheel. the little cut in the upper corner represents a pelton wheel drawn on the same scale, which, given an equal supply of water at the same pressure, would develop the same power as the laxey monster. by the side of the giant the other appears a mere toy. the cream separator. in denmark went to war with germany, and emerged from the short struggle shorn of the provinces of lauenburg, holstein, and schleswig. the loss of the two last, the fairest and most fertile districts of the kingdom, was indeed grievous. the danish king now ruled only over a land consisting largely of moor, marsh, and dunes, apparently worthless for any purpose. but the danes, with admirable courage, entered upon a second struggle, this time with nature. they made roads and railways, dug irrigation ditches, and planted forest trees; and so gradually turned large tracts of what had been useless country into valuable possessions. agriculture being much depressed, owing to the low price of corn, they next gave their attention to the improvement of dairy farming. labour-saving machinery of all kinds was introduced, none more important than the device for separating the fatty from the watery constituents of milk. it would not be too much to say that the separator is largely responsible for the present prosperity of denmark. [illustration: fig. .--section of a cream separator.] how does it work? asks the reader. centrifugal force[ ] is the governing principle. to explain its application we append a sectional illustration (fig. ) of messrs. burmeister and wain's hand-power separator, which may be taken as generally representative of this class of machines. inside a circular casing is a cylindrical bowl, d, mounted on a shaft which can be revolved , times a minute by means of the cog-wheels and the screw thread chased on it near the bottom extremity. milk flows from the reservoir r (supported on a stout arm) through tap a into a little distributer on the top of the separator, and from it drops into the central tube c of the bowl. falling to the bottom, it is flung outwards by centrifugal force, finds an escape upwards through the holes _a a_, and climbs up the perforated grid _e_, the surface of which is a series of pyramidical excrescences, and finally reaches the inner surface of the drum proper. the velocity of rotation is so tremendous that the heavier portions of the milk--that is, the watery--crowd towards the point furthest from the centre, and keep the lighter fatty elements away from contact with the sides of the drum. in the diagram the water is represented by small circles, the cream by small crosses. as more milk enters the drum it forces upwards what is already there. the cap of the drum has an inner jacket, f, which at the bottom _all but touches_ the side of the drum. the distance between them is the merest slit; but the cream is deflected up outside f into space e, and escapes through a hole one-sixteenth of an inch in diameter perforating the plate g. the cream is flung into space k and trickles out of spout b, while the water flies into space h and trickles away through spout a. the "hydro.," used in laundries for wringing clothes by centrifugal force, has a solid outer casing and an inner perforated cylindrical cage, revolved at high speed by a vertical shaft. the wet clothes are placed in the cage, and the machine is started. the water escapes through the perforations and runs down the side of the casing to a drain. after a few minutes the clothes are dry enough for ironing. so great is the centrifugal force that they are consolidated against the sides of the cage, and care is needed in their removal. [ ] inventor of the lathe slide-rest. [ ] living germs; some varieties the cause of disease. [ ] that is, centre-fleeing force. water dropped on a spinning top rushes towards the circumference and is shot off at right angles to a line drawn from the point of parting to the centre of the top. chapter xix. heating and lighting. the hot-water supply--the tank system--the cylinder system--how a lamp works--gas and gasworks--automatic stoking--a gas governor--the gas meter--incandescent gas lighting. hot-water supply. a well-equipped house is nowadays expected to contain efficient apparatus for supplying plenty of hot water at all hours of the day. there is little romance about the kitchen boiler and the pipes which the plumber and his satellites have sometimes to inspect and put right, but the methods of securing a proper circulation of hot water through the house are sufficiently important and interesting to be noticed in these pages. in houses of moderate size the kitchen range does the heating. the two systems of storing and distributing the heated water most commonly used are--( ) the _tank_ system; ( ) the _cylinder_ system. the tank system is shown diagrammatically in fig. . the boiler is situated at the back of the range, and when a "damper" is drawn the fire and hot gases pass under it to a flue leading to the chimney. the almost boiling water rises to the top of the boiler and thence finds its way up the _flow pipe_ into the hot-water tank a, displacing the somewhat colder water there, which descends through the _return pipe_ to the bottom of the boiler. water is drawn off from the flow pipe. this pipe projects some distance through the bottom of a, so that the hottest portion of the contents may be drawn off first. a tank situated in the roof, and fed from the main by a ball-cock valve, communicates with a through the siphon pipe s. the bend in this pipe prevents the ascent of hot water, which cannot sink through water colder than itself. from the top of a an _expansion pipe_ is led up and turned over the cold-water tank to discharge any steam which may be generated in the boiler. a hot-water radiator for warming the house may be connected to the flow and return pipes as shown. since it opens a "short circuit" for the circulation, the water in the tank above will not be so well heated while it is in action. if cocks are fitted to the radiator pipes, the amount of heat thus deflected can be governed. [illustration: fig. .--the "tank" system of hot-water supply.] a disadvantage of the tank system is that the tank, if placed high enough to supply all flows, is sometimes so far from the boiler that the water loses much of its heat in the course of circulation. also, if for any reason the cold water fails, tank a may be entirely emptied, circulation cease, and the water in the boiler and pipes boil away rapidly. the cylinder system (fig. ) is open to neither of these objections. instead of a rectangular tank up aloft, we now have a large copper cylinder situated in the kitchen near the range. the flow and return pipes are continuous, and the cold supply enters the bottom of the cylinder through a pipe with a siphon bend in it. as before, water is drawn off from the flow pipe, and a radiator may be put in the circuit. since there is no draw-off point below the top of the cylinder, even if the cold supply fails the cylinder will remain full, and the failure will be discovered long before there is any danger of the water in it boiling away. [illustration: fig. .--the "cylinder" system of hot-water supply.] boiler explosions are due to obstructions in the pipes. if the expansion pipe and the cold-water supply pipe freeze, there is danger of a slight accumulation of steam; and if one of the circulation pipes is also blocked, steam must generate until "something has to go,"[ ] which is naturally the boiler. assuming that the pipes are quite full to the points of obstruction, the fracture would result from the expansion of the water. steam cannot generate unless there be a space above the water. but the expanding water has stored up the heat which would have raised steam, and the moment expansion begins after fracture this energy is suddenly let loose. steam forms instantaneously, augmenting the effects of the explosion. from this it will be gathered that all pipes should be properly protected against frost; especially near the roof. another cause of disaster is the _furring up_ of the pipes with the lime deposited by hard water when heated. when hard water is used, the pipes will sooner or later be blocked near the boiler; and as the deposit is too hard to be scraped away, periodical renewals are unavoidable. how a lamp works. from heating we turn to lighting, and first to the ordinary paraffin lamp. the two chief things to notice about this are the wick and the chimney. the wick, being made of closely-woven cotton, draws up the oil by what is known as _capillary attraction_. if you dip the ends of two glass tubes, one half an inch, the other one-eighth of an inch in diameter, into a vessel of water, you will notice that the water rises higher in the smaller tube. or get two clean glass plates and lay them face to face, touching at one end, but kept slightly apart at the other by some small object. if they are partly submerged perpendicularly, the water will rise between the plates--furthest on the side at which the two plates touch, and less and less as the other edge is approached. the tendency of liquids to rise through porous bodies is a phenomenon for which we cannot account. mineral oil contains a large proportion of carbon and hydrogen; it is therefore termed hydro-carbon. when oil reaches the top of a lighted wick, the liquid is heated until it turns into gas. the carbon and hydrogen unite with the oxygen of the air. some particles of the carbon apparently do not combine at once, and as they pass through the fiery zone of the flame are heated to such a temperature as to become highly luminous. it is to produce these light-rays that we use a lamp, and to burn our oil efficiently we must supply the flame with plenty of oxygen, with more than it could naturally obtain. so we surround it with a transparent chimney of special glass. the air inside the chimney is heated, and rises; fresh air rushes in at the bottom, and is also heated and replaced. as the air passes through, the flame seizes on the oxygen. if the wick is turned up until the flame becomes smoky and flares, the point has been passed at which the induced chimney draught can supply sufficient oxygen to combine with the carbon of the vapour, and the "free" carbon escapes as smoke. the blower-plate used to draw up a fire (fig. ) performs exactly the same function as the lamp chimney, but on a larger scale. the plate prevents air passing straight up the chimney over the coals, and compels it to find a way through the fire itself to replace the heated air rising up the chimney. [illustration: fig. .--showing how a blower-plate draws up the fire.] gas and gasworks. a lamp is an apparatus for converting hydro-carbon mineral oil into gas and burning it efficiently. the gas-jet burns gases produced by driving off hydro-carbon vapours from coal in apparatus specially designed for the purpose. gas-making is now, in spite of the competition of electric lighting, so important an industry that we shall do well to glance at the processes which it includes. coal gas may be produced on a very small scale as follows:--fill a tin canister (the joints of which have been made by folding the metal, not by soldering) with coal, clap on the lid, and place it, lid downwards, in a bright fire, after punching a hole in the bottom. vapour soon begins to issue from the hole. this is probably at first only steam, due to the coal being more or less damp. but if a lighted match be presently applied the vapour takes fire, showing that coal gas proper is coming off. the flame lasts for a long time. when it dies the canister may be removed and the contents examined. most of the carbon remains in the form of _coke_. it is bulk for bulk much lighter than coal, for the hydrogen, oxygen, and other gases, and some of the carbon have been driven off by the heat. the coke itself burns if placed in a fire, but without any smoke, such as issues from coal. [illustration: fig. .--sketch of the apparatus used in the manufacture of coal gas.] our home-made gas yields a smoky and unsatisfactory flame, owing to the presence of certain impurities--ammonia, tar, sulphuretted hydrogen, and carbon bisulphide. a gas factory must be equipped with means of getting rid of these objectionable constituents. turning to fig. , which displays very diagrammatically the main features of a gas plant, we observe at the extreme right the _retorts_, which correspond to our canister. these are usually long fire-brick tubes of d-section, the flat side at the bottom. under each is a furnace, the flames of which play on the bottom, sides, and inner end of the retort. the outer end projecting beyond the brickwork seating has an iron air-tight door for filling the retort through, immediately behind which rises an iron exit pipe, a, for the gases. tar, which vaporizes at high temperatures, but liquefies at ordinary atmospheric heat, must first be got rid of. this is effected by passing the gas through the _hydraulic main_, a tubular vessel half full of water running the whole length of the retorts. the end of pipe a dips below the surface of the water, which condenses most of the tar and steam. the partly-purified gas now passes through pipe b to the _condensers_, a series of inverted u-pipes standing on an iron chest with vertical cross divisions between the mouths of each u. these divisions dip into water, so that the gas has to pass up one leg of a u, down the other, up the first leg of the second pipe, and so on, till all traces of the tar and other liquid constituents have condensed on the inside of the pipe, from which they drop into the tank below. the next stage is the passage of the _scrubber_, filled with coke over which water perpetually flows. the ammonia gas is here absorbed. there still remain the sulphuretted hydrogen and the carbon bisulphide, both of which are extremely offensive to the nostrils. slaked lime, laid on trays in an air-tight compartment called the _lime purifier_, absorbs most of the sulphurous elements of these; and the coal gas is then fit for use. on leaving the purifiers it flows into the _gasometer_, or gasholder, the huge cake-like form of which is a very familiar object in the environs of towns. the gasometer is a cylindrical box with a domed top, but no bottom, built of riveted steel plates. it stands in a circular tank of water, so that it may rise and fall without any escape of gas. the levity of the gas, in conjunction with weights attached to the ends of chains working over pulleys on the framework surrounding the holder, suffices to raise the holder. [illustration: fig. .--the largest gasholder in the world: south metropolitan gas co., greenwich gas works. capacity, , , cubic feet.] some gasometers have an enormous capacity. the record is at present held by that built for the south metropolitan gas co., london, by messrs. clayton & son of leeds. this monster (of which we append an illustration, fig. ) is feet in diameter and feet high. when fully extended it holds , , cubic feet of gas. owing to its immense size, it is built on the telescopic principle in six "lifts," of feet deep each. the sides of each lift, or ring, except the topmost, have a section shaped somewhat like the letter n. two of the members form a deep, narrow cup to hold water, in which the "dip" member of the ring above it rises and falls. [illustration: fig. .--drawing retorts. (_photo by f. marsh._)] automatic stoking. the labour of feeding the retorts with coal and removing the coke is exceedingly severe. in the illustration on p. (made from a very fine photograph taken by mr. f. marsh of clifton) we see a man engaged in "drawing" the retorts through the iron doors at their outer ends. automatic machinery is now used in large gasworks for both operations. one of the most ingenious stokers is the de brouwer, shown at work in fig. . the machine is suspended from an overhead trolley running on rails along the face of the retorts. coal falls into a funnel at the top of the telescopic pipe p from hoppers in the story above, which have openings, h h, controlled by shutters. the coal as it falls is caught by a rubber belt working round part of the circumference of the large wheel w and a number of pulleys, and is shot into the mouth of the retort. the operator is seen pulling the handle which opens the shutter of the hopper above the feed-tube, and switching on the h.p. electric motor which drives the belt and moves the machine about. one of these feeders will charge a retort feet long in twenty-two seconds. [illustration: fig. .--de brouwer automatic retort charger.] a gas governor. some readers may have noticed that late at night a gas-jet, which a few hours before burned with a somewhat feeble flame when the tap was turned fully on, now becomes more and more vigorous, and finally may flare up with a hissing sound. this is because many of the burners fed by the main supplying the house have been turned off, and consequently there is a greater amount of gas available for the jets still burning, which therefore feel an increased pressure. as a matter of fact, the pressure of gas in the main is constantly varying, owing partly to the irregularity of the delivery from the gasometer, and partly to the fact that the number of burners in action is not the same for many minutes together. it must also be remembered that houses near the gasometer end of the main will receive their gas at a higher pressure than those at the other end. the gas stored in the holders may be wanted for use in the street lamps a few yards away, or for other lamps several miles distant. it is therefore evident that if there be just enough pressure to give a good supply to the nearest lamp, there will be too little a short distance beyond it, and none at all at the extreme point; so that it is necessary to put on enough pressure to overcome the friction on all these miles of pipe, and give just enough gas at the extreme end. it follows that at all intermediate points the pressure is excessive. gas of the average quality is burned to the greatest advantage, as regards its light-giving properties, when its pressure is equal to that of a column of water half an inch high, or about / lb. to the square inch. with less it gives a smoky, flickering light, and with more the combustion is also imperfect. [illustration: fig. .] every house supply should therefore be fitted with a gas governor, to keep the pressure constant. a governor frequently used, the stott, is shown in section in fig. . gas enters from the main on the right, and passes into a circular elbow, d, which has top and bottom apertures closed by the valves v v. attached to the valve shaft is a large inverted cup of metal, the tip of which is immersed in mercury. the pressure at which the governor is to act is determined by the weights w, with which the valve spindle is loaded at the top. as soon as this pressure is exceeded, the gas in c c lifts the metal cup, and v v are pressed against their seats, so cutting off the supply. gas cannot escape from c c, as it has not sufficient pressure to force its way through the mercury under the lip of the cup. immediately the pressure in c c falls, owing to some of the gas being used up, the valves open and admit more gas. when the fluctuations of pressure are slight, the valves never close completely, but merely throttle the supply until the pressure beyond them falls to its proper level--that is, they pass just as much gas as the burners in use can consume at the pressure arranged for. governors of much larger size, but working on much the same principle, are fitted to the mains at the point where they leave the gasometers. they are not, however, sensitive to local fluctuations in the pipes, hence the necessity for separate governors in the house between the meter and the burners. the gas-meter commonly used in houses acts on the principle shown in fig. . the air-tight casing is divided by horizontal and vertical divisions into three gas-chambers, b, c, and d. gas enters at a, and passes to the valve chamber b. the slide-valves of this allow it to pass into c and d, and also into the two circular leather bellows e, f, which are attached to the central division g, but are quite independent of one another. [illustration: fig. .--sketch of the bellows and chambers of a "dry" gas meter.] we will suppose that in the illustration the valves are admitting gas to chamber c and bellows f. the pressure in c presses the circular head of e towards the division g, expelling the contents of the bellows through an outlet pipe (not shown) to the burners in operation within the house. simultaneously the inflation of f forces the gas in chamber d also through the outlet. the head-plates of the bellows are attached to rods and levers (not shown) working the slide-valves in b. as soon as e is fully in, and f fully expanded, the valves begin to open and put the inlet pipe in communication with d and e, and allow the contents of f and c to escape to the outlet. the movements of the valve mechanism operate a train of counting wheels, visible through a glass window in the side of the case. as the bellows have a definite capacity, every stroke that they give means that a certain volume of gas has been ejected either from them or from the chambers in which they move: this is registered by the counter. the apparatus practically has two double-action cylinders (of which the bellows ends are the pistons) working on the same principle as the steam-cylinder (fig. ). the valves have three ports--the central, or exhaust, leading to the outlet, the outer ones from the inlet. the bellows are fed through channels in the division g. incandescent gas lighting. the introduction of the electric arc lamp and the incandescent glow-lamp seemed at one time to spell the doom of gas as an illuminating agent. but the appearance in of the welsbach _incandescent mantle_ for gas-burners opened a prosperous era in the history of gas lighting. the luminosity of a gas flame depends on the number of carbon particles liberated within it, and the temperature to which these particles can be heated as they pass through the intensely hot outside zone of the flame. by enriching the gas in carbon more light is yielded, up to a certain point, with a flame of a given temperature. to increase the heat of the flame various devices were tried before the introduction of the incandescent mantle, but they were found to be too short-lived to have any commercial value. inventors therefore sought for methods by which the emission of light could be obtained from coal gas independently of the incandescence of the carbon particles in the flame itself; and step by step it was discovered that gas could be better employed merely as a heating agent, to raise to incandescence substances having a higher emissivity of light than carbon. dr. auer von welsbach found that the substances most suitable for incandescent mantles were the oxides of certain rare metals, _thorium_, and _cerium_. the mantle is made by dipping a cylinder of cotton net into a solution of nitrate of thorium and cerium, containing per cent. of the former and per cent. of the latter metal. when the fibres are sufficiently soaked, the mantle is withdrawn, squeezed, and placed on a mould to dry. it is next held over a bunsen gas flame and the cotton is burned away, while the nitrates are converted into oxides. the mantle is now ready for use, but very brittle. so it has to undergo a further dipping, in a solution of gun-cotton and alcohol, to render it tough enough for packing. when it is required for use, it is suspended over the burner by an asbestos thread woven across the top, a light is applied to the bottom, and the collodion burned off, leaving nothing but the heat-resisting oxides. the burner used with a mantle is constructed on the bunsen principle. the gas is mixed, as it emerges from the jet, with sufficient air to render its combustion perfect. all the carbon is burned, and the flame, though almost invisible, is intensely hot. the mantle oxides convert the heat energy of the flame into light energy. this is proved not only by the intense whiteness of the mantle, but by the fact that the heat issuing from the chimney of the burner is not nearly so great when the mantle is in position as when it is absent. the incandescent mantle is more extensively used every year. in germany per cent. of gas lighting is on the incandescent system, and in england about per cent. we may notice, as an interesting example of the fluctuating fortunes of invention, that the once doomed gas-burner has, thanks to welsbach's mantle, in many instances replaced the incandescent electric lamps that were to doom it. [ ] if, of course, there is no safety-valve in proper working order included in the installation. chapter xx. various mechanisms. clocks and watches:--a short history of timepieces--the construction of timepieces--the driving power--the escapement--compensating pendulums--the spring balance--the cylinder escapement--the lever escapement--compensated balance-wheels--keyless winding mechanism for watches--the hour hand train. locks:--the chubb lock--the yale lock. the cycle:--the gearing of a cycle--the free wheel--the change-speed gear. agricultural machines:--the threshing-machine--mowing-machines. some natural phenomena:--why sun-heat varies in intensity--the tides--why high tide varies daily. clocks and watches. a short history of timepieces. the oldest device for measuring time is the sun-dial. that of ahaz mentioned in the second book of kings is the earliest dial of which we have record. the obelisks of the egyptians and the curious stone pillars of the druidic age also probably served as shadow-casters. the clepsydra, or water-clock, also of great antiquity, was the first contrivance for gauging the passage of the hours independently of the motion of the earth. in its simplest form it was a measure into which water fell drop by drop, hour levels being marked on the inside. subsequently a very simple mechanism was added to drive a pointer--a float carrying a vertical rack, engaging with a cog on the pointer spindle; or a string from the float passed over a pulley attached to the pointer and rotated it as the float rose, after the manner of the wheel barometer (fig. ). in a.d. charlemagne received from the king of persia a water-clock which struck the hours. it is thus described in gifford's "history of france":--"the dial was composed of twelve small doors, which represented the division of the hours. each door opened at the hour it was intended to represent, and out of it came a small number of little balls, which fell one by one, at equal distances of time, on a brass drum. it might be told by the eye what hour it was by the number of doors that were open, and by the ear by the number of balls that fell. when it was twelve o'clock twelve horsemen in miniature issued forth at the same time and shut all the doors." sand-glasses were introduced about a.d. except for special purposes, such as timing sermons and boiling eggs, they have not been of any practical value. the clepsydra naturally suggested to the mechanical mind the idea of driving a mechanism for registering time by the force of gravity acting on some body other than water. the invention of the _weight-driven clock_ is attributed, like a good many other things, to archimedes, the famous sicilian mathematician of the third century b.c.; but no record exists of any actual clock composed of wheels operated by a weight prior to a.d. so we may take that year as opening the era of the clock as we know it. about peter hele of nuremberg invented the _mainspring_ as a substitute for the weight, and the _watch_ appeared soon afterwards ( a.d.). the pendulum was first adopted for controlling the motion of the wheels by christian huygens, a distinguished dutch mechanician, in . to thomas tompion, "the father of english watchmaking," is ascribed the honour of first fitting a _hairspring_ to the escapement of a watch, in or about the year . he also introduced the _cylinder escapement_ now so commonly used in cheap watches. though many improvements have been made since his time, tompion manufactured clocks and watches which were excellent timekeepers, and as a reward for the benefits conferred on his fellows during his lifetime, he was, after death, granted the exceptional honour of a resting-place in westminster abbey. the construction of timepieces. a clock or watch contains three main elements:--( ) the source of power, which may be a weight or a spring; ( ) the train of wheels operated by the driving force; ( ) the agent for controlling the movements of the train--this in large clocks is usually a pendulum, in small clocks and watches a hairspring balance. to these may be added, in the case of clocks, the apparatus for striking the hour. the driving power. _weights_ are used only in large clocks, such as one finds in halls, towers, and observatories. the great advantage of employing weights is that a constant driving power is exerted. _springs_ occupy much less room than weights, and are indispensable for portable timepieces. the employment of them caused trouble to early experimenters on account of the decrease in power which necessarily accompanies the uncoiling of a wound-up spring. jacob zech of prague overcame the difficulty in by the invention of the _fusee_, a kind of conical pulley interposed between the barrel, or circular drum containing the mainspring, and the train of wheels which the spring has to drive. the principle of the "drum and fusee" action will be understood from fig. . the mainspring is a long steel ribbon fixed at one end to an arbor (the watchmaker's name for a spindle or axle), round which it is tightly wound. the arbor and spring are inserted in the barrel. the arbor is prevented from turning by a ratchet, b, and click, and therefore the spring in its effort to uncoil causes the barrel to rotate. [illustration: fig. .] a string of catgut (or a very fine chain) is connected at one end to the circumference of the drum, and wound round it, the other end being fixed to the larger end of the fusee, which is attached to the driving-wheel of the watch or clock by the intervention of a ratchet and click (not shown). to wind the spring the fusee is turned backward by means of a key applied to the square end a of the fusee arbor, and this draws the string from off the drum on to the fusee. the force of the spring causes the fusee to rotate by pulling the string off it, coil by coil, and so drives the train of wheels. but while the mainspring, when fully wound, turns the fusee by uncoiling the string from the smallest part of the fusee, it gets the advantage of the larger radius as its energy becomes lessened. the fusee is still used for marine chronometers, for some clocks that have a mainspring and pendulum, and occasionally for watches. in the latter it has been rendered unnecessary by the introduction of the _going-barrel_ by swiss watchmakers, who formed teeth on the edge of the mainspring barrel to drive the train of wheels. this kind of drum is called "going" because it drives the watch during the operation of winding, which is performed by rotating the drum arbor to which the inner end of the spring is attached. a ratchet prevents the arbor from being turned backwards by the spring. the adoption of the going-barrel has been made satisfactory by the improvements in the various escapement actions. the escapement. [illustration: fig. .] the spring or weight transmits its power through a train of cogs to the _escapement_, or device for regulating the rate at which the wheels are to revolve. in clocks a _pendulum_ is generally used as the controlling agent. galileo, when a student at pisa, noticed that certain hanging lamps in the cathedral there swung on their cords at an equal rate; and on investigation he discovered the principle that the shorter a pendulum is the more quickly will it swing to and fro. as has already been observed, huygens first applied the principle to the governing of clocks. in fig. we have a simple representation of the "dead-beat" escapement commonly used in clocks. the escape-wheel is mounted on the shaft of the last cog of the driving train, the pallet on a spindle from which depends a split arm embracing the rod and the pendulum. we must be careful to note that the pendulum _controls_ motion only; it does not cause movement. the escape-wheel revolves in a clockwise direction. the two pallets _a_ and _b_ are so designed that only one can rest on the teeth at one time. in the sketch the sloping end of _b_ has just been forced upwards by the pressure of a tooth. this swings the pallet and the pendulum. the momentum of the latter causes _a_ to descend, and at the instant when _b_ clears its tooth _a_ catches and holds another. the left-hand side of _a_, called the _locking-face_, is part of a circle, so that the escape-wheel is held motionless as long as it touches _a_: hence the term, "dead beat"--that is, brought to a dead stop. as the pendulum swings back, to the left, under the influence of gravity, _a_ is raised and frees the tooth. the wheel jerks round, and another tooth is caught by the locking-face of _b_. again the pendulum swings to the right, and the sloping end of _b_ is pushed up once more, giving the pendulum fresh impetus. this process repeats itself as long as the driving power lasts--for weeks, months, or years, as the case may be, and the mechanism continues to be in good working order. compensating pendulums. metal expands when heated; therefore a steel pendulum which is of the exact length to govern a clock correctly at a temperature of ° would become too long at °, and slow the clock, and too short at °, and cause it to gain. in common clocks the pendulum rod is often made of wood, which maintains an almost constant length at all ordinary temperatures. but for very accurate clocks something more efficient is required. graham, the partner of thomas tompion, took advantage of the fact that different kinds of metal have different ratios of expansion to produce a _self-compensating_ pendulum on the principle illustrated by fig. . he used steel for the rod, and formed the _bob_, or weighted end, of a glass jar containing mercury held in a stirrup; the mercury being of such a height that, as the pendulum rod lengthened with a rise of temperature, the mercury expanded _upwards_ sufficiently to keep the distance between the point of suspension and the centre of gravity of the bob always the same. with a fall of temperature the rod shortened, while the mercury sank in the jar. this device has not been improved upon, and is still used in observatories and other places where timekeepers of extreme precision are required. the milled nut s in fig. is fitted at the end of the pendulum rod to permit the exact adjustment of the pendulum's length. for watches, chronometers, and small clocks the spring balance takes the place of the pendulum. we still have an escape-wheel with teeth of a suitable shape to give impulses to the controlling agent. there are two forms of spring escapement, but as both employ a hairspring and balance-wheel we will glance at these before going further. [illustration: fig. .] the _hairspring_ is made of very fine steel ribbon, tempered to extreme elasticity, and shaped to a spiral. the inner end is attached to the arbor of the _balance-wheel_, the outer end to a stud projecting from the plate of the watch. when the balance-wheel, impelled by the escapement, rotates, it winds up the spring. the energy thus stored helps the wheel to revolve the other way during the locking of a tooth of the escape-wheel. the time occupied by the winding and the unwinding depends upon the length of the spring. the strength of the impulse makes no difference. a strong impulse causes the spring to coil itself up more than a weak impulse would; but inasmuch as more energy is stored the process of unwinding is hastened. to put the matter very simply--a strong impulse moves the balance-wheel further, but rotates it quickly; a weak impulse moves it a shorter distance, but rotates it slowly. in fact, the principle of the pendulum is also that of the hairspring; and the duration of a vibration depends on the length of the rod in the one case, and of the spring in the other. motion is transmitted to the balance by one of two methods. either ( ) directly, by a cylinder escapement; or ( ) indirectly, through a lever. [illustration: fig. .--"cylinder" watch escapement.] the cylinder escapement is seen in fig. . the escape-wheel has sharp teeth set on stalks. (one tooth is removed to show the stalk.) the balance-wheel is mounted on a small steel cylinder, with part of the circumference cut away at the level of the teeth, so that if seen from above it would appear like _a_ in our illustration. a tooth is just beginning to shove its point under the nearer edge of the opening. as it is forced forwards, _b_ is revolved in a clockwise direction, winding up the hairspring. when the tooth has passed the nearer edge it flies forward, striking the inside of the further wall of the cylinder, which holds it while the spring uncoils. the tooth now pushes its way past the other edge, accelerating the unwinding, and, as it escapes, the next tooth jumps forward and is arrested by the outside of the cylinder. the balance now reverses its motion, is helped by the tooth, is wound up, locks the tooth, and so on. the lever escapement is somewhat more complicated. the escape-wheel teeth are locked and unlocked by the pallets p p^ projecting from a lever which moves on a pivot (fig. ). the end of the lever is forked, and has a square notch in it. on the arbor of the balance-wheel is a roller, or plate, r, which carries a small pin, i. two pins, b b, projecting from the plate of the watch prevent the lever moving too far. we must further notice the little pin c on the lever, and a notch in the edge of the roller. [illustration: fig. .--"lever" watch escapement.] in the illustration a tooth has just passed under the "impulse face" _b_ of p^ . the lever has been moved upwards at the right end; and its forked end has given an impulse to r, and through it to the balance-wheel. the spring winds up. the pin c prevents the lever dropping, because it no longer has the notch opposite to it, but presses on the circumference of r. as the spring unwinds it strikes the lever at the moment when the notch and c are opposite. the lever is knocked downwards, and the tooth, which had been arrested by the locking-face _a_ of pallet p, now presses on the impulse face _b_, forcing the left end of the lever up. the impulse pin i receives a blow, assisting the unwinding of the spring, and c again locks the lever. the same thing is repeated in alternate directions over and over again. compensating balance-wheels. the watchmaker has had to overcome the same difficulty as the clockmaker with regard to the expansion of the metal in the controlling agent. when a metal wheel is heated its spokes lengthen, and the rim recedes from the centre. now, let us suppose that we have two rods of equal weight, one three feet long, the other six feet long. to an end of each we fasten a -lb. weight. we shall find it much easier to wave the shorter rod backwards and forwards quickly than the other. why? because the weight of the longer rod has more leverage over the hand than has that of the shorter rod. similarly, if, while the mass of the rim of a wheel remains constant, the length of the spokes varies, the effort needed to rotate the wheel to and fro at a constant rate must vary also. graham got over the difficulty with a rod by means of the compensating pendulum. thomas earnshaw mastered it in wheels by means of the _compensating balance_, using the same principle--namely, the unequal expansion of different metals. any one who owns a compensated watch will see, on stopping the tiny fly-wheel, that it has two spokes (fig. ), each carrying an almost complete semicircle of rim attached to it. a close examination shows that the rim is compounded of an outer strip of brass welded to an inner lining of steel. the brass element expands more with heat and contracts more with cold than steel; so that when the spokes become elongated by a rise of temperature, the pieces bend inwards at their free ends (fig. ); if the temperature falls, the spokes are shortened, and the rim pieces bend outwards (fig. ).[ ] this ingenious contrivance keeps the leverage of the rim constant within very fine limits. the screws s s are inserted in the rim to balance it correctly, and very fine adjustment is made by means of the four tiny weights w w. in ships' chronometers,[ ] the rim pieces are _sub_-compensated towards their free ends to counteract slight errors in the primary compensation. so delicate is the compensation that a daily loss or gain of only half a second is often the limit of error. [illustration: fig. . fig. . fig. . a "compensating" watch balance, at normal, super-normal, and sub-normal temperatures.] keyless winding mechanism for watches. the inconvenience attaching to a key-wound watch caused the swiss manufacturers to put on the market, in , watches which dispensed with a separate key. those of our readers who carry keyless watches will be interested to learn how the winding and setting of the hands is effected by the little serrated knob enclosed inside the pendant ring. there are two forms of "going-barrel" keyless mechanism--( ) the rocking bar; ( ) the shifting sleeve. the _rocking bar_ device is shown in figs. , . the milled head m turns a cog, g, which is always in gear with a cog, f. this cog gears with two others, a and b, mounted at each end of the rocker r, which moves on pivot s. a spring, s p, attached to the watch plate presses against a small stud on the rocking bar, and keeps a normally in gear with c, mounted on the arbor of the mainspring. [illustration: fig. .--the winding mechanism of a keyless watch.] to wind the watch, m is turned so as to give f an anti-clockwise motion. the teeth of f now press a downwards and keep it in gear with c while the winding is done. a spring click (marked solid black) prevents the spring uncoiling (fig. ). if f is turned in a clockwise direction it lifts a and prevents it biting the teeth of c, and no strain is thrown on c. to set the hands, the little push-piece p is pressed inwards by the thumb (fig. ) so as to depress the right-hand end of r and bring b into gear with d, which in turn moves e, mounted on the end of the minute-hand shaft. the hands can now be moved in either direction by turning m. on releasing the push-piece the winding-wheels engage again. the _shifting sleeve_ mechanism has a bevel pinion in the place of g (fig. ) gearing with the mainspring cog. the shaft of the knob m is round where it passes through the bevel and can turn freely inside it, but is square below. on the square part is mounted a little sliding clutch with teeth on the top corresponding with the other teeth on the under side of the bevel-wheel, and teeth similar to those of g (fig. ) at the end. the clutch has a groove cut in the circumference, and in this lies the end of a spring lever which can be depressed by the push-piece. the mechanism much resembles on a small scale the motor car changing gear (fig. ). normally, the clutch is pushed up the square part of the knob shaft by the spring so as to engage with the bevel and the winding-wheels. on depressing the clutch by means of the push-piece it gears with the minute-hand pinion, and lets go of the bevel. [illustration: fig. .--the hand-setting mechanism in action.] in one form of this mechanism the push-piece is dispensed with, and the minute-wheel pinion is engaged by pulling the knob upwards. the hour-hand train. [illustration: fig. .--the hour-hand train of a clock.] the teeth of the mainspring drum gear with a cog on the minute-hand shaft, which also carries one of the cogs of the escapement train. the shaft is permitted by the escapement to revolve once an hour. fig. shows diagrammatically how this is managed. the hour-hand shaft a (solid black) can be moved round inside the cog b, driven by the mainspring drum. it carries a cog, c. this gears with a cog, d, having three times as many teeth. the cog e, united to d, drives cog f, having four times as many teeth as e. to f is attached the collar g of the hour-hand. f and g revolve outside the minute-hand shaft. on turning a, c turns d and e, e turns f and the hour-hand, which revolves / of / = / as fast as a.[ ] * * * * * locks. on these unfortunately necessary mechanisms a great deal of ingenuity has been expended. with the advance of luxury and the increased worship of wealth, it becomes more and more necessary to guard one's belongings against the less scrupulous members of society. [illustration: fig. .] the simplest form of lock, such as is found in desks and very cheap articles, works on the principle shown in fig. . the bolt is split at the rear, and the upper part bent upwards to form a spring. the under edge has two notches cut in it, separated by a curved excrescence. the key merely presses the bolt upwards against the spring, until the notch, engaging with the frame, moves it backwards or forwards until the spring drives the tail down into the other notch. this primitive device affords, of course, very little security. an advance is seen in the tumbler lock. [illustration: fig. .] the bolt now can move only in a horizontal direction. it has an opening cut in it with two notches (figs. , ). behind the bolt lies the _tumbler_ t (indicated by the dotted line), pivoted at the angle on a pin. from the face of the tumbler a stud, s, projects through the hole in the bolt. this stud is forced into one or other of the notches by the spring, s^ , which presses on the tail of the tumbler. [illustration: fig. .] in fig. the key is about to actuate the locking mechanism. the next diagram (fig. ) shows how the key, as it enters the notch on the lower side of the bolt to move it along, also raises the tumbler stud clear of the projection between the two notches. by the time that the bolt has been fully "shot," the key leaves the under notch and allows the tumbler stud to fall into the rear locking-notch. a lock of this type also can be picked very easily, as the picker has merely to lift the tumbler and move the bolt along. barron's lock, patented in , had two tumblers and two studs; and the opening in the bolt had notches at the top as well as at the bottom (fig. ). this made it necessary for both tumblers to be raised simultaneously to exactly the right height. if either was not lifted sufficiently, a stud could not clear its bottom notch; if either rose too far, it engaged an upper notch. the chances therefore were greatly against a wrong key turning the lock. [illustration: fig. .--the bolt of a barron lock.] the chubb lock is an amplification of this principle. it usually has several tumblers of the shape shown in fig. . the lock stud in these locks projects from the bolt itself, and the openings, or "gates," through which the stud must pass as the lock moves, are cut in the tumblers. it will be noticed that the forward notch of the tumbler has square serrations in the edges. these engage with similar serrations in the bolt stud and make it impossible to raise the tumbler if the bolt begins to move too soon when a wrong key is inserted. [illustration: fig. .--tumbler of chubb lock.] fig. is a chubb key with eight steps. that nearest the head ( ) operates a circular revolving curtain, which prevents the introduction of picking tools when a key is inserted and partly turned, as the key slot in the curtain is no longer opposite that in the lock. step moves the bolt. [illustration: fig. .--a chubb key.] in order to shoot the bolt the height of the key steps must be so proportioned to the depth of their tumblers that all the gates in the tumblers are simultaneously raised to the right level for the stud to pass through them, as in fig. . here you will observe that the tumbler d on the extreme right (lifted by step of the key) has a stud, d s, projecting from it over the other tumblers. this is called the _detector tumbler_. if a false key or picking tool is inserted it is certain to raise one of the tumblers too far. the detector is then over-lifted by the stud d s, and a spring catch falls into a notch at the rear. it is now impossible to pick the lock, as the detector can be released only by the right key shooting the bolt a little further in the locking direction, when a projection on the rear of the bolt lifts the catch and allows the tumbler to fall. the detector also shows that the lock has been tampered with, since even the right key cannot move the bolt until the overlocking has been performed. [illustration: fig. .--a chubb key raising all the tumblers to the correct height.] each tumbler step of a large chubb key can be given one of thirty different heights; the bolt step one of twenty. by merely transposing the order of the steps in a six-step key it is possible to get different combinations. by diminishing or increasing the heights the possible combinations may be raised to the enormous total of , , ! [illustration: fig. .--section of a yale lock.] the yale lock, which comes from america, works on a quite different system. its most noticeable feature is that it permits the use of a very small key, though the number of combinations possible is still enormous (several millions). in our illustrations (figs. , , ) we show the mechanism controlling the turning of the key. the keyhole is a narrow twisted slot in the face of a cylinder, g (fig. ), which revolves inside a larger fixed cylinder, f. as the key is pushed in, the notches in its upper edge raise up the pins a^ , b^ , c^ , d^ , e^ , until their tops exactly reach the surface of g, which can now be revolved by the key in fig. , and work the bolt through the medium of the arm h. (the bolt itself is not shown.) if a wrong key is inserted, either some of the lower pins will project upwards into the fixed cylinder f (see fig. ), or some of the pins in f will sink into g. it is then impossible to turn the key. [illustration: fig. .--yale key turning.] there are other well-known locks, such as those invented by bramah and hobbs. but as these do not lend themselves readily to illustration no detailed account can be given. we might, however, notice the _time_ lock, which is set to a certain hour, and can be opened by the right key or a number of keys in combination only when that hour is reached. another very interesting device is the _automatic combination_ lock. this may have twenty or more keys, any one of which can lock it; but the same one must be used to _un_lock it, as the key automatically sets the mechanism in favour of itself. with such a lock it would be possible to have a different key for every day in the month; and if any one key got into wrong hands it would be useless unless it happened to be the one which last locked the lock. [illustration: fig. .--the wrong key inserted. the pins do not allow the lock to be turned.] * * * * * the cycle. there are a few features of this useful and in some ways wonderful contrivance which should be noticed. first, the gearing of a cycle. to a good many people the expression "geared to inches," or , or , as the case may be, conveys nothing except the fact that the higher the gear the faster one ought to be able to travel. let us therefore examine the meaning of such a phrase before going farther. the safety cycle is always "geared up"--that is, one turn of the pedals will turn the rear wheel more than once. to get the exact ratio of turning speed we count the teeth on the big chain-wheel, and the teeth on the small chain-wheel attached to the hub of the rear wheel, and divide the former by the latter. to take an example:--the teeth are and in number respectively; the ratio of speed therefore = / = / = - / . one turn of the pedal turns the rear wheel - / times. the gear of the cycle is calculated by multiplying this result by the diameter of the rear wheel in inches. thus a -inch wheel would in this case give a gear of - / × = inches. one turn of the pedals on a machine of this gear would propel the rider as far as if he were on a high "ordinary" with the pedals attached directly to a wheel inches in diameter. the gearing is raised or lowered by altering the number ratio of the teeth on the two chain-wheels. if for the -tooth wheel we substituted one of teeth the gearing would be-- / × inches = inches. a handy formula to remember is, gearing = t/_t_ × d, where t = teeth on large chain-wheel; _t_ = teeth on small chain-wheel; and d = diameter of driving-wheel in inches. two of the most important improvements recently added to the cycle are--( ) the free wheel; ( ) the change-speed gear. the free wheel is a device for enabling the driving-wheel to overrun the pedals when the rider ceases pedalling; it renders the driving-wheel "free" of the driving gear. it is a ratchet specially suited for this kind of work. from among the many patterns now marketed we select the micrometer free-wheel hub (fig. ), which is extremely simple. the _ratchet-wheel_ r is attached to the hub of the driving-wheel. the small chain-wheel (or "chain-ring," as it is often called) turns outside this, on a number of balls running in a groove chased in the neck of the ratchet. between these two parts are the _pawls_, of half-moon shape. the driving-wheel is assumed to be on the further side of the ratchet. to propel the cycle the chain-ring is turned in a clockwise direction. three out of the six pawls at once engage with notches in the ratchet, and are held tightly in place by the pressure of the chain-ring on their rear ends. the other three are in a midway position. [illustration: fig. .] when the rider ceases to pedal, the chain-ring becomes stationary, but the ratchet continues to revolve. the pawls offer no resistance to the ratchet teeth, which push them up into the semicircular recesses in the chain-ring. each one rises as it passes over a tooth. it is obvious that driving power cannot be transmitted again to the road wheel until the chain-wheel is turned fast enough to overtake the ratchet. the change-speed gear. a gain in speed means a loss in power, and _vice versâ_. by gearing-up a cycle we are able to make the driving-wheel revolve faster than the pedals, but at the expense of control over the driving-wheel. a high-geared cycle is fast on the level, but a bad hill-climber. the low-geared machine shows to disadvantage on the flat, but is a good hill-climber. similarly, the express engine must have large driving-wheels, the goods engine small driving-wheels, to perform their special functions properly. in order to travel fast over level country, and yet be able to mount hills without undue exertion, we must be able to do what the motorist does--change gear. two-speed and three-speed gears are now very commonly fitted to cycles. they all work on the same principle, that of the epicyclic train of cog-wheels, the mechanisms being so devised that the hub turns more slowly than, at the same speed as, or faster than the small chain-wheel,[ ] according to the wish of the rider. we do not propose to do more here than explain the principle of the epicyclic train, which means "a wheel on (or running round) a wheel." lay a footrule on the table and roll a cylinder along it by the aid of a second rule, parallel to the first, but resting on the cylinder. it will be found that, while the cylinder advances six inches, the upper rule advances twice that distance. in the absence of friction the work done by the agent moving the upper rule is equal to that done in overcoming the force which opposes the forward motion of the cylinder; and as the distance through which the cylinder advances is only half that through which the upper rule advances, it follows that the _force_ which must act on the upper rule is only half as great as that overcome in moving the cylinder. the carter makes use of this principle when he puts his hand to the top of a wheel to help his cart over an obstacle. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] now see how this principle is applied to the change-speed gear. the lower rule is replaced by a cog-wheel, c (fig. ); the cylinder by a cog, b, running round it; and the upper rule by a ring, a, with internal teeth. we may suppose that a is the chain-ring, b a cog mounted on a pin projecting from the hub, and c a cog attached to the fixed axle. it is evident that b will not move so fast round c as a does. the amount by which a will get ahead of b can be calculated easily. we begin with the wheels in the position shown in fig. . a point, i, on a is exactly over the topmost point of c. for the sake of convenience we will first assume that instead of b running round c, b is revolved on its axis for one complete revolution in a clockwise direction, and that a and c move as in fig. . if b has teeth, c , and a , a will have been moved / = / of a revolution in a clockwise direction, and c / = / of a revolution in an anti-clockwise direction. now, coming back to what actually does happen, we shall be able to understand how far a rotates round c relatively to the motion of b, when c is fixed and b rolls (fig. ). b advances / of distance round c; a advances / + / = / of distance round b. the fractions, if reduced to a common denominator, are as : , and this is equivalent to (number of teeth on a): + (teeth on a + teeth on c.) to leave the reader with a very clear idea we will summarize the matter thus:--if t = number of teeth on a, _t_ = number of teeth on c, then movement of a: movement of b:: t + _t_: t. here is a two-speed hub. let us count the teeth. the chain-ring (= a) has internal teeth, and the central cog (= c) on the axle has teeth. there are four cogs (= b) equally spaced, running on pins projecting from the hub-shell between a and c. how much faster than b does a run round c? apply the formula:--motion of a: motion of b:: + : . that is, while a revolves once, b and the hub and the driving-wheel will revolve only / = / of a turn. to use scientific language, b revolves per cent. slower than a. this is the gearing we use for hill-climbing. on the level we want the driving-wheel to turn as fast as, or faster than, the chain-ring. to make it turn at the same rate, both a and c must revolve together. in one well-known gear this is effected by sliding c along the spindle of the wheel till it disengages itself from the spindle, and one end locks with the plate which carries a. since b is now being pulled round at the bottom as well as the top, it cannot rotate on its own axis any longer, and the whole train revolves _solidly_--that is, while a turns through a circle b does the same. to get an _increase_ of gearing, matters must be so arranged that the drive is transmitted from the chain-wheel to b, and from a to the hub. while b describes a circle, a and the driving-wheel turn through a circle and a part of a circle--that is, the driving-wheel revolves faster than the hub. given the same number of teeth as before, the proportional rates will be a = , b = , so that the gear _rises_ per cent. by means of proper mechanism the power is transmitted in a three-speed gear either ( ) from chain-wheel to a, a to b, b to wheel = _low_ gear; or ( ) from chain-wheel to a and c simultaneously = solid, normal, or _middle_ gear; or ( ) from chain-wheel to b, b to a, a to wheel = _high_ gear. in two-speed gears either or is omitted. * * * * * agricultural machines. the threshing-machine. bread would not be so cheap as it is were the flail still the only means of separating the grain from the straw. what the cream separator has done for the dairy industry (p. ), the threshing-machine has done for agriculture. a page or two ought therefore to be spared for this useful invention. [illustration: fig. .--section of a threshing machine.] in fig. a very complete fore-and-aft section of the machine is given. after the bands of the sheaves have been cut, the latter are fed into the mouth of the _drum_ a by the feeder, who stands in the feeding-box on the top of the machine. the drum revolves at a very high velocity, and is fitted with fluted beaters which act against a steel concave, or breastwork, b, the grain being threshed out of the straw in passing between the two. the breastwork is provided with open wires, through which most of the threshed grain, cavings (short straws), and chaff passes on to a sloping board. the straw is flung forward on to the shakers c, which gradually move the straw towards the open end and throw it off. any grain, etc., that has escaped the drum falls through the shakers on to d, and works backwards to the _caving riddles_, or moving sieves, e. the _main blower_, by means of a revolving fan, n, sends air along the channel x upwards through these riddles, blowing the short straws away to the left. the grain, husks, and dust fall through e on to g, over the end of which they fall on to the _chaff riddle_, h. a second column of air from the blower drives the chaff away. the heavy grain, seeds, dust, etc., fall on to i, j, and k in turn, and are shaken until only the grain remains to pass along l to the elevator bottom, m. an endless band with cups attached to it scoops up the grain, carries it aloft, and shoots it into hopper p. it then goes through the shakers q, r, is dusted by the _back end blower_, s, and slides down t into the open end of the rotary screen-drum u, which is mounted on the slope, so that as it turns the grain travels gradually along it. the first half of the screen has wires set closely together. all the small grain that falls through this, called "thirds," passes into a hopper, and is collected in a sack attached to the hopper mouth. the "seconds" fall through the second half of the drum, more widely spaced, into their sack; and the "firsts" fall out of the end and through a third spout. mowing-machines. [illustration: fig. .] the ordinary _lawn--mower_ employs a revolving reel, built up of spirally-arranged knives, the edges of which pass very close to a sharp plate projecting from the frame of the mower. each blade, as it turns, works along the plate, giving a shearing cut to any grass that may be caught between the two cutting edges. the action is that of a pair of scissors (fig. ), one blade representing the fixed, the other the moving knife. if you place a cylinder of wood in the scissors it will be driven forward by the closing of the blades, and be marked by them as it passes along the edges. the same thing happens with grass, which is so soft that it is cut right through. hay-cutter. the _hay-cutter_ is another adaptation of the same principle. a cutter-bar is pulled rapidly backwards and forwards in a frame which runs a few inches above the ground by a crank driven by the wheels through gearing. to the front edge of the bar are attached by one side a number of triangular knives. the frame carries an equal number of spikes pointing forward horizontally. through slots in these the cutter-bar works, and its knives give a drawing cut to grass caught between them and the sides of the spikes. * * * * * some natural phenomena. why sun-heat varies in intensity. the more squarely parallel heat-rays strike a surface the greater will be the number that can affect that surface. this is evident from figs. , , where a b is an equal distance in both cases. the nearer the sun is to the horizon, the more obliquely do its rays strike the earth. hence midday is necessarily warmer than the evening, and the tropics, where the sun stands overhead, are hotter than the temperate zones, where, even in summer at midday, the rays fall more or less on the slant. [illustration: fig. .] [illustration: fig. .] the atmospheric envelope which encompasses the earth tends to increase the effect of obliquity, since a slanting ray has to travel further through it and is robbed of more heat than a vertical ray. the tides. all bodies have an attraction for one another. the earth attracts the moon, and the moon attracts the earth. now, though the effect of this attraction is not visible as regards the solid part of the globe, it is strongly manifested by the water which covers a large portion of the earth's surface. the moon attracts the water most powerfully at two points, that nearest to it and that furthest away from it; as shown on an exaggerated scale in fig. . since the earth and the water revolve as one mass daily on their axis, every point on the circumference would be daily nearest to and furthest from the moon at regular intervals, and wherever there is ocean there would be two tides in that period, were the moon stationary as regards the earth. (it should be clearly understood that the tides are not great currents, but mere thickenings of the watery envelope. the inrush of the tide is due to the temporary rise of level.) [illustration: fig. .] [illustration: fig. .] why high tide varies daily. the moon travels round the earth once in twenty-eight days. in fig. the point _a_ is nearest the moon at, say, twelve noon. at the end of twenty-four hours it will have arrived at the same position by the compass, but yet not be nearest to the moon, which has in that period moved on / th of a revolution round the earth.[ ] consequently high tide will not occur till _a_ has reached position _b_ and overtaken the moon, as it were, which takes about an hour on the average. this explains why high tide occurs at intervals of more than twelve hours. [illustration: fig. .--relative positions of sun, moon, and earth at "spring" tides.] [illustration: fig. .--relative positions of sun, moon, and earth at "neap" tides.] neap tides and spring tides. the sun, as well as the moon, attracts the ocean, but with less power, owing to its being so much further away. at certain periods of the month, sun, earth, and moon are all in line. sun and moon then pull together, and we get the highest, or _spring_ tides (fig. ). when sun and moon pull at right angles to one another--namely, at the first and third quarters--the excrescence caused by the moon is flattened (fig. ), and we get the lowest, or _neap_ tides. [ ] in both figs. and the degree of expansion is very greatly exaggerated. [ ] as the sun passes the meridian (twelve o'clock, noon) the chronometer's reading is taken, and the longitude, or distance east or west of greenwich, is reckoned by the difference in time between local noon and that of the chronometer. [ ] for much of the information given here about clocks and watches the author is indebted to "the history of watches," by mr. j.f. kendal. [ ] we shall here notice only those gears which are included in the hub of the driving-wheel. [ ] the original position of the moon is indicated by the dotted circle. index. note.--figures in italics signify that an illustration of the thing referred to appears on the page. aberration, spherical, of lens, . acoustics, . achromatic lens, . action carriage of piano, . advancing the spark, . air-gun, _ _. air-pump for cycle tyres, _ _; for westinghouse brake, . alternating currents, ; dynamo, . amperage, . angle of advance, , ; incidence, ; reflection, . aorta, . arc lamp, . archimedes, . armature, . arteries, . arterial blood, . atmospheric pressure, . auditory nerve, . automatic brakes, ; signalling, ; stoker, . backfall, . balance-wheel, . ball cock, , _ _. balloon, fire, ; gas, . barometer, aneroid, , _ _; and weather, ; fortin's, _ _; meaning of, ; simple, _ _; wheel, _ _. beau de rochas, . bell, diving, _ _; electric, , _ _. bellows of organ, . bioscope, . blades, turbine, _ _, . block system, , . blood, arterial, ; circulation of, _ _, _ _, ; venous, . blower-plate, , _ _. boat, sails of, . boiler, babcock and wilcox, _ _, ; explosions, , ; fire-tube, ; fittings, ; lancashire, , _ _; locomotive, _ _, ; multitubular, ; principle of, ; stored energy in, ; vertical, _ _; water supply to, ; water-tube, . brakes, hydraulic, ; motor car, ; railway, ; vacuum, , _ _, _ _; westinghouse, , _ _, _ _. bramah, , . breezes, land and sea, . brushes of dynamo, , _ _. bunsen burner, . burning-glass, . camera, the, ; pinhole, _ _, _ _. canals, semicircular, . capillary attraction, ; veins, . carbon dioxide, , ; monoxide, . carburetter, , _ _. cardan shaft, . _carmania_, the, . centrifugal force, . change-speed gear, , . chassis of motor car, . circulation of water in a boiler, _ _, _ _, _ _; of water in a motor car, , _ _. clarionet, . clock, first weight-driven, ; water, . clutch of motor car, . coal, as fuel, ; gas, ; gas making, ; gas plant, _ _; gas, purification of, . cochlea, . coherer, . coil, ruhmkorff, . coke, . combinations in chubb lock, ; yale lock, . combustion, , ; perfect, . compensating gear, , _ _. compound engines, ; arrangement of, ; invention of, . compound locomotives, . compound microscope, . condenser, marine, , _ _; of ruhmkorff coil, . conduit, . convex lens, image cast by, _ _. conjugate foci, . cornet, . corti, rods of, . coxwell, . cream separator, , _ _. current, reversal of electric, _ _, ; transformation of, . cushioning of steam, . cycle, gearing of, . cylinder, hydraulic press, _ _; steam, _ _. danes, . dead point, . de brouwer stoker, . detector in chubb lock, . diving-bell, _ _; simple, _ _, _ _. diving-dress, . direction of current in dynamo circuit, . diver's feats, ; helmet, _ _; lamp, _ _. donkey-engines, . doorstop, self-closing, . double-cylinder engines, . draught, forced, , _ _; induced, . drum and fusee, _ _. durability of motor-car engine, . d-valve, . dynamo, alternating, , ; brushes, _ _; compound, ; continuous-current, ; multipolar, ; series wound, _ _; shunt wound, _ _; simple, , _ _. ear, the, _ _, _ _; a good, , ; sensitiveness of, . eccentric, _ _, ; setting of, . edison, thomas, . edison-bell phonograph, . electricity, current, ; forms of, ; nature of, ; static, . electric bell, , _ _; signalling, ; slot, . electroplating, , _ _. electro-magnets, . endolymph, . engines, compound, ; donkey, ; double-cylinder, ; internal-combustion, , ; reciprocating, . escapement of timepieces, ; cylinder, _ _; lever, , _ _. ether, . eustachian tube, . eye, human, , _ _; self-accommodation of, . expansive working of steam, . faraday, michael, . field, magnetic, ; magnets, ; ring, . filters, ; maignen, _ _; berkefeld, . filtration beds, . flute, . flying-machines, . fly-wheel, use of, . focus, meaning of, ; principal, . foci, conjugate, . force, lines of, . forces, component, . free wheel, _ _. furring-up of pipes, . fusee, drum and, . galileo, , , . galilean telescope, _ _. gas, coal, ; governor, ; meter, ; traps, ; works, . gasometer, ; largest, _ _, . gauge, steam, , _ _; water, , _ _. gear, compensating, , _ _. gear-box of motor car, . gearing of cycle, . glaisher, . gland, , . glass, flint and crown, . going-barrel for watches, . gooch reversing gear, . governors, speed, ; of motor car, , _ _. graham, . gramophone, ; records, , ; reproducer, _ _. hairspring, . hay-cutter, . heart, the, ; disease, ; rate of pulsation of, ; size of, . heat of sun, . hele, peter, . helmet, diver's, _ _. helmholtz, , . hero of alexandria, . herschel, . hertz, dr., . hertzian waves, . hot-water supply, . hour-hand train in timepieces, _ _. household water supply, . hughes type-printer, . hydraulic press, , _ _. hydro, . ignition of charge in motor-car cylinder, , _ _. image and object, relative positions of, ; distortion of, . incandescent gas mantle, ; electric lamp, . incus, . index mechanism of water-meter, . indicator of electric bell, . induction coil, ; uses of, . injector, ; giffard's, _ _; principle of, ; self-starting, . interlocking of signals, , . internal-combustion engine, . iris of eye, ; stop, . kelvin, lord, . keyless winding mechanism, , _ _, . kite, . lamp, arc, ; how it works, ; incandescent, ; manufacture of incandescent lamps, . lap of slide-valve, _ _, . larynx, . laxey wheel, _ _, . leads, . lenses, ; correction of for colour, , _ _; focus of, ; rectilinear, _ _; spherical aberration in, . levers, signal, colours of, . limit of error in cylinder, . light, electric, ; nature of, ; propagation of, . li hung chang, . lindsay, james bowman, . lines of force, , . "linking up," . locks, ; barron, ; bramah, ; chubb, , ; hobbs, ; simplest, _ _; tumbler, _ _; yale, _ _. locking gear for signals, . locomotive, electric, ; advantages of, . lungs, . magic-lantern, , _ _. magnet, ; permanent, , ; temporary, . magnetism, . magnetic needle, influence of current on, . mainspring, invention of, . malleus, . marconi, , . marine chronometers, ; delicacy of, . marine speed governor, . marine turbine, advantages of, . maudslay, henry, . maxim, sir hiram, . micrometer free wheel, . micro-photography, . microscope, ; compound, , _ _; in telescope, ; simple, _ _. mineral oil, . mirror, parabolic, , _ _; plane, _ _. morse, , ; code, ; inker, ; sounder, . motor car, the, ; electric, . mouth, . mowing-machines, . musical sounds, . nerve, auditory, ; optic, . nodes on a string, ; column of air, . note, fundamental, ; quality of, . niagara falls, power station at, . organ, the, , _ _; bellows, ; console, ; echo, solo, swell, great, and choir, ; electric and pneumatic, ; largest in the world, ; pedals, ; pipes, ; pipes, arrangement of, ; sound-board, _ _; wind-chest, . otto cycle, . overtones, . pallets of organ, . parallel arrangement of electric lamps, . paris, siege of, . pedals of organ, . pelton wheel, _ _. pendulum, ; compensating, , _ _. perilymph, . perry, professor, . petrol, . phonograph, ; governor, _ _; recorder, , _ _; records, making of, ; reproducer, ; tracings on record of, _ _. pianoforte, ; sounding-board, ; striking mechanism, ; strings, . piccolo, . pipes, closed, ; flue, ; open, ; organ, ; reed, , _ _; tuning, . piston valve, . pneumatic tyres, . poldhu, signalling station at, . points, railway, , _ _; and signals in combination, . poles of a magnet, . popoff, professor a., , . power, transmission of, . preece, sir william, . primary winding of induction coil, . pump, air, ; bucket, , _ _; force, ; most marvellous, ; westinghouse air, . railway brakes, ; signalling, . rays, converging and diverging, _ _; heat, concentrated by lens, _ _; light, , , , . records, master, , . reciprocation, . reed, human, ; pipes, , _ _. reflecting telescope, . relays, telegraphic, , . retina, . retorts, . reversing gear, ; allan, ; gooch, ; radial, . rocking bar mechanism for watches, . rods of corti, . ruhmkorff coil, , _ _. safety-valve, , _ _, . sand-glasses, . scissors, action of, _ _. secondary winding of induction coil, . series arrangement of electric lamps, . series winding of dynamo, _ _. shunt wound dynamo, _ _. sight, long and short, . signalling, automatic, ; electric, ; pneumatic, ; power, . signal levers, _ _. signals, interlocking of, ; position of, ; railway, ; single line, . silencer on motor cars, . siphon, _ _. slide-valve, , , ; setting of, . sliders, . sound, nature of, ; board of organ, ; board of piano, . spagnoletti disc instrument, . sparking-plug, _ _. spectacles, use of, . spectrum, colours of, . speed governors, , _ _, _ _; hartwell, ; marine, . speed of motor cars, . spot, blind, in eye, ; yellow, in eye, . spring balance for watches, ; compensating, , _ _. stapes, . steam, what it is, ; energy of, ; engines, ; engines, reciprocating, _ _; expansive working of, , ; gauge, ; gauge, principle of, ; turbine, ; turbine, de laval, , _ _; turbine, hero's, ; turbine, parsons, , _ _; volume of, as compared with water, . stephenson, george, , . stop, in lens, ; iris, ; use of, . sun-dial of ahaz, . syntonic transmission of wireless messages, . talking-machines, . tapper in wireless telegraphy receiver, . tappet arm, . telegraph, electric, ; insulator, _ _; needle, _ _; recording, ; sounder, . telegraphy, high-speed, ; wireless, . telephone, ; bell, _ _; circuit, double-line, ; circuit, general arrangement, _ _, ; exchange, _ _, . telephony, submarine, . telescope, ; galilean, _ _; prismatic, _ _; reflecting, ; terrestrial, _ _. threshing-machine, , _ _. thurston, professor, . tides, ; high, ; neap and spring, . timbre, . tompion, thomas, . torricelli, . trachea, . train staff signalling, ; single, ; and ticket, ; electric, . transformation of current, , . transmission of power, , _ _. transmitter, edison telephone, ; granular carbon, , _ _. triple-valve, . trolley arm, . turbines, steam, . _turbinia_, the, . tympanum, , , . universal joint, . vacuum brake, , _ _, _ _. vacuum chamber of aneroid barometer, _ _. valve, piston, ; safety, ; of internal-combustion engine, . valves of the heart, . veins, ; capillary, ; pulmonary, . ventral segments, . ventricles, . vibration of columns of air, , ; of rods, ; of strings, ; of strings, conditions regulating, . _viper_, the, . virag, pollak--high-speed telegraphy, . vitreous humour, . voltage, , . vowel sounds, . wasborough, matthew, . watches, first, . water cock, _ _; engines, ; gauge, , _ _; jacket, , ; meter, _ _; supply, ; turbines, , ; wheels, . watt, james, , , . welsbach incandescent mantle, . westinghouse air-brake, , _ _, _ _; george, . wheatstone needle instrument, , ; automatic transmitter, . wind, why it blows, ; action of on kites, ; on sails, . windmills, . window, oval, in ear, ; round, in ear, . wireless telegraphy, ; advance of, ; receiver, , ; syntonic, ; transmitter, , _ _. yale lock, _ _, _ _. yellow spot, in eye, . zech, jacob, . zeiss field-glasses, . the end. proofreading team at www.pgdp.net [illustration] scientific american supplement no. new york, april , scientific american supplement. vol. xxv., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. archÆology.--the subterranean temples of india.--the subterranean temples of india described and illustrated, the wonderful works of the ancient dwellers in hindostan.-- illustrations. ii. biography.--general f. perrier.--portrait and biography of the french geodesian, his triangulations in algiers and corsica.-- illustration. the crown prince of germany--prince william and his son.-- biographical note of prince william, the heir to the german throne.-- illustration. iii. biology.--poisons.--abstract of a lecture by prof. meymott tidy, giving the relations of poisons to life. the president's annual address to the royal microscopical society.--the theory of putrefaction and putrefactive organisms.--exhaustive review of the subject. iv. chemistry.--molecular weights.--a new and simple method of determining molecular weights for unvolatilizable substances. v. civil engineering.--concrete.--by john lundie.--a practical paper on the above subject.--the uses and proper methods of handling concrete, machine mixing contrasted with hand mixing. timber and some of its diseases.--by h. marshall ward.--the continuation of this important treatise on timber destruction, the fungi affecting wood, and treatment of the troubles arising therefrom. vi. engineering.--estrade's high speed locomotive.--a comparative review of the engineering features of m. estrade's new engine, designed for speeds of to miles an hour.-- illustration. machine designing.--by john b. sweet.--first portion of a franklin institute lecture on this eminently practical subject.-- illustrations. vii. meteorology.--the peak of teneriffe.--electrical and meteorological observations on the summit of teneriffe. viii. miscellaneous.--analysis of a hand fire grenade.--by chas. catlett and r.c. price.--the contents of a fire grenade and its origin. how to catch and preserve moths and butterflies.--practical directions for collectors. the clavi harp.--a new instrument, a harp played by means of keys arranged on a keyboard-- illustration. inquiries regarding the incubator.--by p.h. jacobs.--notes concerning the incubator described in a previous issue (supplement, no. ).--practical points. ix. physics.--the direct optical projection of electro-dynamic lines of force, and other electro-dynamic phenomena.--by prof. j.w. moore--second portion of this profusely illustrated paper, giving a great variety of experiments on the phenomena of loop-shaped conductors.-- illustrations. the mechanics of a liquid.--an ingenious method of measuring the volume of fibrous and porous substances without immersion in any liquid.-- illustration. x. physiology.--artificial mother for infants.--an apparatus resembling an incubator for infants that are prematurely born.--results attained by its use.-- illustration. gastrostomy.--artificial feeding for cases of obstructed oesophagus.--the apparatus and its application.-- illustrations. xi. photography.--how to make photo-printing plates.--the process of making relief plates for printers. xii. technology.--improved current meter.--a simple apparatus for measuring air and water currents without indexes or other complications.-- illustration. the flower industry of grasse.--methods of manufacturing perfumes in france.--the industry as practiced in the town of grasse. volute double distilling condenser.--a distiller and condenser for producing fresh water from sea water.-- illustrations. the argand burner.--the origin of the invention of the argand burner. * * * * * [illustration: the crown prince of germany--prince william and son [from a photograph]] the crown prince of germany--prince william and his son. at a moment when the entire world has its eyes fixed upon the invalid of the villa zurio, it appears to us to be of interest to publish the portrait of his son, prince william. the military spirit of the hohenzollerns is found in him in all its force and exclusiveness. it was hoped that the accession of the crown prince to the throne of germany would temper the harshness of it and modernize its aspect, but the painful disease from which he is suffering warns us that the moment may soon come in which the son will be called to succeed the emperor william, his grandfather, of whom he is morally the perfect portrait. like him, he loves the army, and makes it the object of his entire attention. no colonel more scrupulously performs his duty than he, when he enters the quarters of the regiment of red hussars whose chief he is. his solicitude for the army manifests itself openly. it is not without pride that he regards his eldest son, who will soon be six years old, and who is already clad in the uniform of a fusilier of the guard. prince william is a soldier in spirit, just as harsh toward himself as severe toward others. so he is the friend and emulator of prince von bismarck, who sees in him the depositary of the military traditions of the house of prussia, and who is preparing him by his lessons and his advice to receive and preserve the patrimony that his ancestors have conquered. prince william was born january , . on the th of february, , he married princess augusta victoria, daughter of the duke of sleswick-holstein. their eldest son, little prince william, represented with his father in our engraving, was born at potsdam, may , .--_l'illustration._ * * * * * general f. perrier. francois perrier, who was born at valleraugue (gard), on the th of april, , descended from an honorable family of protestants, of cevennes. after finishing his studies at the lyceum of nimes and at st. barbe college, he was received at the polytechnic school in , and left it in , as a staff officer. endowed with perseverance and will, he owed all his grades and all his success to his splendid conduct and his important labors. lieutenant in , captain in , major of cavalry in , lieutenant-colonel in , he received a year before his death the stars of brigadier-general. he was commander of the legion of honor and president of the council-general of his department. general perrier long ago made a name for himself in science. after some remarkable publications upon the trigonometrical junction of france and england ( ) and upon the triangulation and leveling of corsica ( ), he was put at the head of the geodesic service of the army in . in , the learned geodesian was sent as a delegate to the conference of berlin for settling the boundaries of the new greco-turkish frontiers. in january of the same year, he was elected a member of the academy of sciences, as successor to m. de tessan. he was a member of the bureau of longitudes from . in , perrier was sent to florida to observe the transit of venus. thanks to his activity and ability, his observations were a complete success. thenceforward, his celebrity continued to increase until his last triangulating operations in algeria. [illustration: general francois perrier.] "do you not remember," said mr. janssen recently to the academy of sciences, "the feeling of satisfaction that the whole country felt when it learned the entire success of that grand geodesic operation that united spain with our algeria over the mediterranean, and passed through france a meridian arc extending from the north of england as far as to the sahara, that is to say, an arc exceeding in length the greatest arcs that had been measured up till then? this splendid result attracted all minds, and rendered perrier's name popular. but how much had this success been prepared by long and conscientious labors that cede in nothing to it in importance? the triangulation and leveling of corsica, and the connecting of it with the continent; the splendid operations executed in algeria, which required fifteen years of labor, and led to the measurement of an arc of parallels of nearly ° in extent, that offers a very peculiar interest for the study of the earth's figure; and, again, that revision of the meridian of france in which it became necessary to utilize all the progress that had been made since the beginning of the century in the construction of instruments and in methods of observation and calculation. and it must be added that general perrier had formed a school of scientists and devoted officers who were his co-laborers, and upon whom we must now rely to continue his work." the merits of general perrier gained him the honor of being placed at the head of a service of high importance, the geographical service of the army, to the organization of which he devoted his entire energy. in general perrier, the man ceded in nothing to the worker and scientist. good, affable, generous, he joined liveliness and good humor with courage and energy. incessantly occupied with the prosperity and grandeur of his country, he knew that true patriotism does not consist in putting forth vain declamations, but in endeavoring to accomplish useful and fruitful work.--_la nature._ general perrier died at montpellier on the th of february, . * * * * * the president's annual address to the royal microscopical society.[ ] [footnote : delivered by the rev. dr. dallinger, f.r.s., at the annual meeting of the royal microscopical society, feb. , .--_nature._] retrospect may involve regret, but can scarcely involve anxiety. to one who fully appreciates the actual, and above all the potential, importance of this society in its bearing upon the general progress of scientific research in every field of physical inquiry, the responsibilities of president will not be lightly, while they may certainly be proudly, undertaken. i think it may be now fairly taken for granted that, as this society has, from the outset, promoted and pointed to the higher scientific perfection of the microscope, so now, more than ever, it is its special function to place this in the forefront as its _raison d'etre_. the microscope has been long enough in the hands of amateur and expert alike to establish itself as an instrument having an application to every actual and conceivable department of human research; and while in the earliest days of this society it was possible for a zealous fellow to have seen, and been more or less familiar with, all the applications to which it then had been put, it is different to-day. specialists in the most diverse areas of research are assiduously applying the instrument to their various subjects, and with results that, if we would estimate aright, we must survey with instructed vision the whole ground which advancing science covers. from this it is manifest that this society cannot hope to infold, or at least to organically bind to itself, men whose objects of research are so diverse. but these are all none the less linked by one inseverable bond; it is the microscope; and while, amid the inconceivable diversity of its applications, it remains manifest that this society has for its primary object the constant progress of the instrument--whether in its mechanical construction or its optical appliances; whether the improvements shall bear upon the use of high powers or low powers; whether it shall be improvement that shall apply to its commercial employment, its easier professional application, or its most exalted scientific use; so long as this shall be the undoubted aim of the royal microscopical society, its existence may well be the pride of englishmen, and will commend itself more and more to men of all countries. this, and this only, can lift such a society out of what i believe has ceased to be its danger, that of forgetting that in proportion as the optical principles of the microscope are understood, and the theory of microscopical vision is made plain, the value of the instrument over every region to which it can be applied, and in all the varied hands that use it, is increased without definable limit. it is therefore by such means that the true interests of science are promoted. it is one of the most admirable features of this society that it has become cosmopolitan in its character in relation to the instrument, and all the ever-improving methods of research employed with it. from meeting to meeting it is not one country, or one continent even, that is represented on our tables. nay, more, not only are we made familiar with improvements brought from every civilized part of the world, referring alike to the microscope itself and every instrument devised by specialists for its employment in every department of research; but also, by the admirable persistence of mr. crisp and mr. jno. mayall, jr., we are familiarized with every discovery of the old forms of the instrument wherever found or originally employed. the value of all this cannot be overestimated, for it will, even where prejudices as to our judgment may exist, gradually make it more and more clear that this society exists to promote and acknowledge improvements in every constituent of the microscope, come from whatever source they may; and, in connection with this, to promote by demonstrations, exhibitions, and monographs the finest applications of the finest instruments for their respective purposes. to give all this its highest value, of course, the theoretical side of our instrument must occupy the attention of the most accomplished experts. we may not despair that our somewhat too practical past in this respect may right itself in our own country; but meantime the splendid work of german students and experts is placed by the wise editors of our journal within the reach of all. i know of no higher hope for this important society than that it may continue in ever increasing strength to promote, criticise, and welcome from every quarter of the world whatever will improve the microscope in itself and in any of its applications, from the most simple to the most complex and important in which its employment is possible. there are two points of some practical interest to which i desire for a few moments to call your attention. the former has reference to the group of organisms to which i have for so many years directed your attention, viz., the "monads," which throughout i have called "putrefactive organisms." there can be no longer any doubt that the destructive process of putrefaction is essentially a process of fermentation. the fermentative saprophyte is as absolutely essential to the setting up of destructive rotting or putrescence in a putrescible fluid as the torula is to the setting up of alcoholic fermentation in a saccharine fluid. make the presence of torulæ impossible, and you exclude with certainty fermentative action. in precisely the same way, provide a proteinaceous solution, capable of the highest putrescence, but absolutely sterilized, and placed in an optically pure or absolutely calcined air; and while these conditions are maintained, no matter what length of time may be suffered to elapse, the putrescible fluid will remain absolutely without trace of decay. but suffer the slightest infection of the protected and pure air to take place, or, from some putrescent source, inoculate your sterilized fluid with the minutest atom, and shortly turbidity, offensive scent, and destructive putrescence ensue. as in the alcoholic, lactic, or butyric ferments, the process set up is shown to be dependent upon and concurrent with the vegetative processes of the demonstrated organisms characterizing these ferments; so it can be shown with equal clearness and certainty that the entire process of what is known as putrescence is equally and as absolutely dependent on the vital processes of a given and discoverable series of organisms. now it is quite customary to treat the fermentative agency in putrefaction as if it were wholly bacterial, and, indeed, the putrefactive group of bacteria are now known as saprophytes, or saprophytic bacteria, as distinct from morphologically similar, but physiologically dissimilar, forms known as parasitic or pathogenic bacteria. it is indeed usually and justly admitted that _b. termo_ is the exciting cause of fermentative putrefaction. cohn has in fact contended that it is the distinctive ferment of all putrefactions, and that it is to decomposing proteinaceous solutions what _torula cerevisiæ_ is to the fermenting fluids containing sugar. in a sense, this is no doubt strictly true: it is impossible to find a decomposing proteinaceous solution, at any stage, without finding this form in vast abundance. but it is well to remember that in nature putrefactive ferments must go on to an extent rarely imitated or followed in the laboratory. as a rule, the pabulum in which the saprophytic organisms are provided and "cultured" is infusions, or extracts of meat carefully filtered, and, if vegetable matter is used, extracts of fruit, treated with equal care, and if needful neutralized, are used in a similar way. to these may be added all the forms of gelatine, employed in films, masses and so forth. but in following the process of destructive fermentation as it takes place in large masses of tissue, animal or vegetable, but far preferably the former, as they lie in water at a constant temperature of from ° to ° f., it will be seen that the fermentative process is the work, not of one organism, nor, judging by the standard of our present knowledge, of one specified class of vegetative forms, but by organisms which, though related to each other, are in many respects greatly dissimilar, not only morphologically, but also embryologically, and even physiologically. moreover, although this is a matter that will want most thorough and efficient inquiry and research to understand properly its conditions, yet it is sufficiently manifest that these organisms succeed each other in a curious and even remarkable manner. each does a part in the work of fermentative destruction; each aids in splitting up into lower and lower compounds the elements of which the masses of degrading tissue are composed; while, apparently, each set in turn does by vital action, coupled with excretion, ( ) take up the substances necessary for its own growth and multiplication; ( ) carry on the fermentative process; and ( ) so change the immediate pabulum as to give rise to conditions suitable for its immediate successor. now the point of special interest is that there is an apparent adaptation in the form, functions, mode of multiplication, and order of succession in these fermentative organisms, deserving study and fraught with instruction. let it be remembered that the aim of nature in this fermentative action is not the partial splitting of certain organic compounds, and their reconstruction in simpler conditions, but the ultimate setting free, by saprophytic action, of the elements locked up in great masses of organic tissue--the sending back into nature of the only material of which future organic structures are to be composed. i have said that there can be no question whatever that _bacterium termo_ is the pioneer of saprophytes. exclude _b. termo_ (and therefore with it all its congeners), and you can obtain no putrefaction. but wherever, in ordinary circumstances, a decomposable organic mass, say the body of a fish, or a considerable mass of the flesh of a terrestrial animal, is exposed in water at a temperature of ° to ° f., _b. termo_ rapidly appears, and increases with a simply astounding rapidity. it clothes the tissues like a skin, and diffuses itself throughout the fluid. the exact chemical changes it thus effects are not at present clearly known; but the fermentative action is manifestly concurrent with its multiplication. it finds its pabulum in the mass it ferments by its vegetative processes. but it also produces a visible change in the enveloping fluid, and noxious gases continuously are thrown off. in the course of a week or more, dependent on the period of the year, there is, not inevitably, but as a rule, a rapid accession of spiral forms, such as _spirillum volutans_, _s. undula_, and similar forms, often accompanied by _bacterium lineola_; and the whole interspersed still with inconceivable multitudes of _b. termo_. these invest the rotting tissues liked an elastic garment, but are always in a state of movement. these, again, manifestly further the destructive ferment, and bring about a softness and flaccidity in the decomposing tissues, while they without doubt, at the same time, have, by their vital activity and possible secretions, affected the condition of the changing organic mass. there can be, so far as my observations go, no certainty as to when, after this, another form of organism will present itself; nor, when it does, which of a limited series it will be. but, in a majority of observed cases, a loosening of the living investment of bacterial forms takes place, and simultaneously with this, the access of one or two forms of my putrefactive monads. they were among the first we worked at; and have been, by means of recent lenses, among the last revised. mr. s. kent named them _cercomonas typica_ and _monas dallingeri_ respectively. they are both simple oval forms, but the former has a flagellum at both ends of the longer axis of the body, while the latter has a single flagellum in front. the principal difference is in their mode of multiplication by fission. the former is in every way like a bacterium in its mode of self-division. it divides, acquiring for each half a flagellum in division, and then, in its highest vigor, in about four minutes, each half divides again. the second form does not divide into two, but into many, and thus although the whole process is slower, develops with greater rapidity. but both ultimately multiply--that is, commence new generations--by the equivalent of a sexual process. these would average about four times the size of _bacterium termo_; and when once they gain a place on and about the putrefying tissues, their relatively powerful and incessant action, their enormous multitude, and the manner in which they glide over, under, and beside each other, as they invest the fermenting mass, is worthy of close study. it has been the life history of these organisms, and not their relations as ferment, that has specially occupied my fullest attention; but it would be in a high degree interesting if we could discover, or determine, what besides the vegetative or organic processes of nutrition are being effected by one, or both, of these organisms on the fast yielding mass. still more would it be of interest to discover what, if any, changes were wrought in the pabulum, or fluid generally. for after some extended observations i have found that it is only after one or other or both, of these organisms have performed their part in the destructive ferment, that subsequent and extremely interesting changes arise. it is true that in some three or four instances of this saprophytic destruction of organic tissues, i have observed that, after the strong bacterial investment, there has arisen, not the two forms just named, nor either of them, but one or other of the striking forms now called _tetramitus rostratus_ and _polytoma uvella_; but this has been in relatively few instances. the rule is that _cercomonas typica_ or its congener precedes other forms, that not only succeed them in promoting and carrying to a still further point the putrescence of the fermenting substance, but appear to be aided in the accomplishment of this by mechanical means. by this time the mass of tissue has ceased to cohere. the mass has largely disintegrated, and there appears among the countless bacterial and monad forms some one, and sometimes even three forms, that while they at first swim and gyrate, and glide about the decomposing matter, which is now much less closely invested by _cercomonas typica_, or those organisms that may have acted in its place, they also resort to an entirely new mode of movement. one of these forms is _heteromita rostrata_, which, it will be remembered, in addition to a front flagellum, has also a long fiber or flagellum-like appendage that gracefully trails as it swims. at certain periods of its life they anchor themselves in countless billions all over the fermenting tissues, and as i have described in the life history of this form, they coil their anchored fiber, as does a vorticellan, bringing the body to the level of the point of anchorage, then shoot out the body with lightning-like rapidity, and bring it down like a hammer on some point of the decomposition. it rests here for a second or two, and repeats the process; and this is taking place by what seems almost like rhythmic movement all over the rotting tissue. the results are scarcely visible in the mass. but if a group of these organisms be watched, attached to a small particle of the fermenting tissue, it will be seen to gradually diminish, and at length to disappear. now, there are at least two other similar forms, one of which, _heteromita uncinata_, is similar in action, and the other of which, _dallingeria drysdali_, is much more powerful, being possessed of a double anchor, and springing down upon the decadent mass with relatively far greater power. now, it is under the action of these last forms that in a period varying from one month to two or three the entire substance of the organic tissues disappears, and the decomposition has been designated by me "exhausted"; nothing being left in the vessel but slightly noxious and pale gray water, charged with carbonic acid, and a fine, buff colored, impalpable sediment at the bottom. my purpose is not, by this brief notice, to give an exhaustive, or even a sufficient account, of the progress of fermentative action, by means of saprophytic organisms, on great masses of tissue; my observations have been incidental, but they lead me to the conclusion that the fermentative process is not only not carried through by what are called saprophytic bacteria, but that a _series_ of fermentative organisms arise, which succeed each other, the earlier ones preparing the pabulum or altering the surrounding medium, so as to render it highly favorable to a succeeding form. on the other hand, the succeeding form has a special adaptation for carrying on the fermentative destruction more efficiently from the period at which it arises, and thus ultimately of setting free the chemical elements locked up in dead organic compounds. that these later organisms are saprophytic, although not bacterial, there can be no doubt. a set of experiments, recorded by me in the proceedings of this society some years since, would go far to establish this (_monthly microscopical journal_, , p. ). but it may be readily shown, by extremely simple experiments, that these forms will set up fermentative decomposition rapidly if introduced in either a desiccated or living condition, or in the spore state, into suitable but sterilized pabulum. thus while we have specific ferments which bring about definite and specific results, and while even infusions of proteid substances may be exhaustively fermented by saprophytic bacteria, the most important of all ferments, that by which nature's dead organic masses are removed, is one which there is evidence to show is brought about by the successive vital activities of a series of adapted organisms, which are forever at work in every region of the earth. there is one other matter of some interest and moment on which i would say a few words. to thoroughly instructed biologists, such words will be quite needless; but, in a society of this kind, the possibilities that lie in the use of the instrument are associated with the contingency of large error, especially in the biology of the minuter forms of life, unless a well grounded biological knowledge form the basis of all specific inference, to say nothing of deduction. i am the more encouraged to speak of the difficulty to which i refer, because i have reason to know that it presents itself again and again in the provincial societies of the country, and is often adhered to with a tenacity worthy of a better cause. i refer to the danger that always exists, that young or occasional observers are exposed to, amid the complexities of minute animal and vegetable life, of concluding that they have come upon absolute evidences of the transformation of one minute form into another; that in fact they have demonstrated cases of heterogenesis. this difficulty is not diminished by the fact that on the shelves of most microscopical societies there is to be found some sort of literature written in support of this strange doctrine. you will pardon me for allusion again to the field of inquiry in which i have spent so many happy hours. it is, as you know, a region of life in which we touch, as it were, the very margin of living things. if nature were capricious anywhere, we might expect to find her so here. if her methods were in a slovenly or only half determined condition, we might expect to find it here. but it is not so. know accurately what you are doing, use the precautions absolutely essential, and through years of the closest observation it will be seen that the vegetative and vital processes generally, of the very simplest and lowliest life forms, are as much directed and controlled by immutable laws as the most complex and elevated. the life cycles, accurately known, of monads repeat themselves as accurately as those of rotifers or planarians. and of course, on the very surface of the matter, the question presents itself to the biologist why it should not be so. the irrefragable philosophy of modern biology is that the most complex forms of living creatures have derived their splendid complexity and adaptations from the slow and majestically progressive variation and survival from the simpler and the simplest forms. if, then, the simplest forms of the present and the past were not governed by accurate and unchanging laws of life, how did the rigid certainties that manifestly and admittedly govern the more complex and the most complex come into play? if our modern philosophy of biology be, as we know it is, true, then it must be very strong evidence indeed that would lead us to conclude that the laws seen to be universal break down and cease accurately to operate where the objects become microscopic, and our knowledge of them is by no means full, exhaustive, and clear. moreover, looked at in the abstract, it is a little difficult to conceive why there should be more uncertainty about the life processes of a group of lowly living things than there should be about the behavior, in reaction, of a given group of molecules. the triumph of modern knowledge is the certainty, which nothing can shake, that nature's laws are immutable. the stability of her processes, the precision of her action, and the universality of her laws, is the basis of all science, to which biology forms no exception. once establish, by clear and unmistakable demonstration, the life history of an organism, and truly some change must have come over nature as a whole, if that life history be not the same to-morrow as to-day; and the same to one observer, in the same conditions, as to another. no amount of paradox would induce us to believe that the combining proportions of hydrogen and oxygen had altered, in a specified experimenter's hands, in synthetically producing water. we believe that the melting point of platinum and the freezing point of mercury are the same as they were a hundred years ago, and as they will be a hundred years hence. now, carefully remember that so far as we can see at all, it must be so with life. life inheres in protoplasm; but just as you cannot get _abstract matter_--that is, matter with no properties or modes of motion--so you cannot get _abstract_ protoplasm. every piece of living protoplasm we see has a history; it is the inheritor of countless millions of years. its properties have been determined by its history. it is the protoplasm of some definite form of life which has inherited its specific history. it can be no more false to that inheritance than an atom of oxygen can be false to its properties. all this, of course, within the lines of the great secular processes of the darwinian laws; which, by the way, could not operate at all if caprice formed any part of the activities of nature. but let me give a practical instance of how what appears like fact may override philosophy, if an incident, or even a group of incidents, _per se_ are to control our judgment. eighteen years ago i was paying much attention to vorticellæ. i was observing with some pertinacity _vorticella convallaria_; for one of the calices in a group under observation was in a strange and semi-encysted state, while the remainder were in full normal activity. i watched with great interest and care, and have in my folio still the drawings made at the time. the stalk carrying this individual calyx fell upon the branch of vegetable matter to which the vorticellan was attached, and the calyx became perfectly globular; and at length there emerged from it a small form with which, in this condition, i was quite unfamiliar; it was small, tortoise-like in form, and crept over the branch on setæ or hair-like pedicels; but, carefully followed, i found it soon swam, and at length got the long neck-like appendage of _amphileptus anser_! here then was the cup or calyx of a definite vorticellan form changing into (?) an absolutely different infusorian, viz., _amphileptus anser_! now i simply reported the _fact_ to the liverpool microscopical society, with no attempt at inference; but two years after i was able to explain the mystery, for, finding in the same pond both _v. convallaria_ and _a. anser_, i carefully watched their movements, and saw the _amphileptus_ seize and struggle with a calyx of _convallaria_, and absolutely become encysted upon it, with the results that i had reported two years before. and there can be no doubt but this is the key to the cases that come to us again and again of minute forms suddenly changing into forms wholly unlike. it is happily among the virtues of the man of science to "rejoice in the truth," even though it be found at his expense; and true workers, earnest seekers for nature's methods, in the obscurest fields of her action, will not murmur that this source of danger to younger microscopists has been pointed out, or recalled to them. and now i bid you, as your president, farewell. it has been all pleasure to me to serve you. it has enlarged my friendships and my interests, and although my work has linked me with the society for many years, i have derived much profit from this more organic union with it; and it is a source of encouragement to me, and will, i am sure, be to you, that, after having done with simple pleasure what i could, i am to be succeeded in this place of honor by so distinguished a student of the phenomena of minute life as dr. hudson. i can but wish him as happy a tenure of office as mine has been. * * * * * inquiries regarding the incubator. p.h. jacobs. space in the _rural_ is valuable, and so important a subject as artificial incubation cannot perhaps be made entirely plain to a novice in a few articles; but as interested parties have written for additional information, it may interest others to answer them here. among the questions asked are: "does the incubator described in the _rural_ dispense entirely with the use of a lamp, using at intervals a bucket of water to maintain proper temperature? i fear this will not be satisfactory unless the incubator is kept in a warm room or cellar." all incubators must be kept in a warm location, whether operated by a lamp or otherwise. the warmer the room or cellar, the less warmth required to be supplied. bear in mind that the incubator recommended has four inches of sawdust surrounding it, and more sawdust would still be an advantage. the sawdust is not used to protect against the outside temperature, but to absorb and hold a large amount of heat, and that is the secret of its success. the directions given were to first fill the tank with boiling water and allow it to remain for hours. in the meantime the sawdust absorbs the heat, and more boiling water is then added until the egg-drawer is about or degrees. by this time there is a quantity of stored heat in the sawdust. the eggs will cool the drawer to . the loss of heat (due to its being held by the sawdust) will be very slow. all that is needed then is to supply that which will be lost in hours, and a bucket of boiling water should keep the heat about correct, if added twice a day, but it may require more, as some consideration must be given to fluctuations of the temperature of the atmosphere. the third week of incubation, owing to animal heat from the embryo chicks, a bucket of boiling water will sometimes hold temperature for hours. no objection can be urged against attaching a lamp arrangement, but a lamp is dangerous at night, while the flame must be regulated according to temperature. the object of giving the hot water method was to avoid lamps. we have a large number of them in use (no lamps) here, and they are equal to any others in results. with all due respect to some inquirers, the majority of them seem afraid of the work. now, there is some work with all incubators. what is desired is to get rid of the anxiety. i stated that a bucket of water twice a day would suffice. i trusted to the judgment of the reader somewhat. of course, if the heat in the egg drawer is degrees, and the weather cold, it may then take a wash boiler full of water to get the temperature back to degrees, but when it is at keep it there, even if it occasionally requires two buckets of boiling water. to judge of what may be required, let us suppose the operator looks at the thermometer in the morning, and it is exactly degrees. he estimates that it will lose a little by night, and draws off half a bucket of water. at night he finds it at . knowing that it is on what we term "the down grade," he applies a bucket and a half (always allowing for the night being colder than the day). as stated, the sawdust will not allow the drawer to become too cold, as it gives off heat to the drawer. and, as the sawdust absorbs, it is not easy to have the heat too high. one need not even look at the drawer until the proper times. no watching--the incubator regulates itself. if a lamp is used, too much heat may accumulate. the flame must be occasionally turned up or down, and the operator must remain at home and watch it, while during the third week he will easily cook his eggs. the incubator can be made at home for so small a sum (about $ for the tank, $ for faucet, etc., with feet of lumber) that it will cost but little to try it. a piece of glass can be placed in front of the egg drawer, if preferred. if the heat goes down to , or rises at times to , no harm is done. but it works well, and hatches, the proof being that hundreds are in use. i did not give the plan as a theory or an experiment. they are in practical use here, and work alongside of the more expensive ones, and have been in use for four years. to use a lamp attachment, all that is necessary is to have a no. burner lamp with a riveted sheet-iron chimney, the chimney fitting over the flame, like an ordinary globe, and extending the chimney (using an elbow) through the tank from the rear, ending in front. it should be soldered at the tank. the heat from the lamp will then pass through the chimney and consequently warm the surrounding water.--_rural new-yorker._ [for description and illustrations of this incubator see supplement, no. .] * * * * * the peak of teneriffe. the hon. ralph abercromby made a trip to the island of teneriffe in october, , for the purpose of making some electrical and meteorological observations, and now gives some of the results which he obtained, which may be summarized as follows: the electrical condition of the peak of teneriffe was found to be the same as in every other part of the world. the potential was moderately positive, from to volts, at ft. in. from the ground, even at considerable altitudes; but the tension rose to volts on the summit of the peak, , ft., and to volts on the top of the rock of gayga, , feet. a large number of halos were seen associated with local showers and cloud masses. the necessary ice dust appeared to be formed by rising currents. the shadow of the peak was seen projected against the sky at sunset. the idea of a southwest current flowing directly over the northeast trade was found to be erroneous. there was always a regular vertical succession of air currents in intermediate directions at different levels from the surface upward, so that the air was always circulating on a complicated screw system. * * * * * estrade's high speed locomotive. we illustrate a very remarkable locomotive, which has been constructed from the designs of m. estrade, a french engineer. this engine was exhibited last year in paris. although the engine was built, m. estrade could not persuade any railway company to try it for him, and finally he applied to the french government, who have at last sanctioned the carrying out of experiments with it on one of the state railway lines. the engine is in all respects so opposed to english ideas that we have hitherto said nothing about it. as, however, it is going to be tried, an importance is given to it which it did not possess before; and, as a mechanical curiosity, we think it is worth the consideration of our readers. in order that we may do m. estrade no injustice, we reproduce here in a condensed form, and in english, the arguments in its favor contained in a paper written by m. max de nansouty, c.e., who brought m. estrade's views before the french institution of civil engineers, on may , . m. nansouty's paper has been prepared with much care, and contains a great deal of useful data quite apart from the estrade engine. the paper in question is entitled "_memoire relatif au materiel roulant a grand vitesse_," d.m. estrade. about thirty years ago, m. estrade, formerly pupil of the polytechnic school, invented rolling stock for high speed under especial conditions, and capable of leading to important results, more especially with regard to speed. following step by step the progress made in the construction of railway stock, the inventor, from time to time, modified and improved his original plan, and finally, in , arrived at the conception of a system entirely new in its fundamental principles and in its execution. a description of this system is the object of the memoir. the great number of types of locomotives and carriages now met with in france, england, and the united states renders it difficult to combine their advantages, as m. estrade proposed to do, in a system responding to the requirements of the constructor. his principal object, however, has been to construct, under specially favorable conditions, a locomotive, tender, and rolling stock adapted to each other, so as to establish a perfect accord between these organs when in motion. it is, in fact, a complete train, and not, as sometimes supposed, a locomotive only, of an especial type, which has been the object he set before him. before entering into other considerations, we shall first give a description of the stock proposed by m. estrade. the idea of the invention consists in the use of coupled wheels of large diameter and in the adoption of a new system of double suspension. the locomotive and tender we illustrate were constructed by mm. boulet & co. the locomotive is carried on six driving wheels, feet inches in diameter. the total weight of the engine is thus utilized for adhesion. the accompanying table gives the principal dimensions: table i. +---------------------------------------+ | | ft. in. | +-----------------------+---------------+ |total length of engine.| | +-----------------------+---------------+ |width between frames. | | +-----------------------+---------------+ |wheel base, total. | | +-----------------------+---------------+ |diameter of cylinder. | ½ | +-----------------------+---------------+ |length of stroke. | ½ | +-----------------------+---------------+ |grate surface. | sq. feet. | +-----------------------+---------------+ |total heating surface. | , sq. ft. | +-----------------------+---------------+ |weight empty. | tons. | +-----------------------+---------------+ |weight full. | tons. | +---------------------------------------+ the high speeds-- to miles an hour--in view of which this stock has been constructed have, it will be seen, caused the elements relative to the capacity of the boiler and the heating surfaces to be developed as much as possible. it is in this, in fact, that one of the great difficulties of the problem lies, the practical limit of stability being fixed by the diameter of the driving wheels. speed can only be obtained by an expenditure of steam which soon becomes such as rapidly to exhaust the engine unless the heating surface is very large. the tender, also fitted with wheels of ft. in. in diameter, offers no particular feature; it is simply arranged so as to carry the greatest quantity of coal and water. m. estrade has also designed carriages. one has been constructed by mm. reynaud, bechade, gire & co., which has very few points in common with those in general use. independently of the division of the compartments into two stories, wheels ft. in. in diameter are employed, and the double system of suspension adopted. two axles, ft. apart, support, by means of plate springs, an iron framing running from end to end over the whole length, its extremities being curved toward the ground. each frame carries in its turn three other plate springs, to which the body is suspended by means of iron tie-rods serving to support it. this is then a double suspension, which at once appears to be very superior to the systems adopted up to the present time. the great diameter of the wheels has necessitated the division into two stories. the lower story is formed of three equal parts, lengthened toward the axles by narrow compartments, which can be utilized for luggage or converted into lavatories, etc. above is one single compartment with a central passage, which is reached by staircases at the end. all the vehicles of the same train are to be united at this level by jointed platforms furnished with hand rails. it is sufficient to point out the general disposition, without entering into details which do not affect the system, and which must vary for the different classes and according to the requirements of the service. [illustration: m. estrade's high speed locomotive.] m. nansouty draws a comparison between the diameters of the driving wheels and cylinders of the principal locomotives now in use and those of the estrade engine as set forth in the following table. we only give the figures for coupled engines: table ii. +--------------------+------------------+-----------+-------------+ | | diameter of | size of | | | | driving wheels. | cylinder. | position of | | | ft. in. | in. in. | cylinder. | +--------------------+------------------+-----------+-------------+ |great eastern | | × | inside | +--------------------+------------------+-----------+-------------+ |south-eastern | | × | " | +--------------------+------------------+-----------+-------------+ |glasgow and | | | | |southwestern | | × | " | +--------------------+------------------+-----------+-------------+ |midland, | | × | " | +--------------------+------------------+-----------+-------------+ |north-eastern | | ½ × | " | +--------------------+------------------+-----------+-------------+ |london and | | | | |north-western | | × | " | +--------------------+------------------+-----------+-------------+ |lancashire and | | | | |yorkshire | | ½ × | " | +--------------------+------------------+-----------+-------------+ |north british | | × | " | +--------------------+------------------+-----------+-------------+ |nord | | × | " | +--------------------+------------------+-----------+-------------+ |paris-orleans, | | × ½ | outside. | +--------------------+------------------+-----------+-------------+ |ouest | | ¼ × ½| " | +-----------------------------------------------------------------+ this table, the examination of which will be found very instructive, shows that there are already in use: for locomotives with single drivers, diameters of ft., ft. in., and ft.; ( ) for locomotives with four coupled wheels, diameters ft. to ft. there is therefore an important difference between the diameters of the coupled wheels of ft. and those of ft. in., as conceived by m. estrade. however, the transition is not illogically sudden, and if the conception is a bold one, "it cannot," says m. nansouty, "on the other hand, be qualified as rash." he goes on to consider, in the first place: especial types of uncoupled wheels, the diameters of which form useful samples for our present case. the engines of the bristol and exeter line are express tender engines, adopted on the english lines in , some specimens of which are still in use.[ ] these engines have ten wheels, the single drivers in the center, ft. in diameter, and a four-wheeled bogie at each end. the driving wheels have no flanges. the bogie wheels are ft. in diameter. the cylinders have a diameter of ½ in. and a piston stroke of in. the boiler contains tubes, and the total weight of the engine is tons. these locomotives, constructed for ft. gauge, have attained a speed of seventy-seven miles per hour. [footnote : m. nansouty is mistaken. none of the bristol and exeter tank engines with. ft. wheels are in use, so far as we know. ed. e.] the single driver locomotives of the great northern are powerful engines in current use in england. the driving wheels carry tons, the heating surface is , square feet, the diameters of the cylinders in., and that of the driving wheels ft. in. we have here, then, a diameter very near to that adopted by m. estrade, and which, together with the previous example, forms a precedent of great interest. the locomotive of the great northern has a leading four-wheeled bogie, which considerably increases the steadiness of the engine, and counterbalances the disturbing effect of outside cylinders. acting on the same principles which have animated m. estrade, that is to say, with the aim of reducing the retarding effects of rolling friction, the constructor of the locomotive of the great northern has considerably increased the diameter of the wheels of the bogie. in this engine all the bearing are inside, while the cylinders are outside and horizontal. the tender has six wheels, also of large dimensions. it is capable of containing three tons and a half of coal and about , gallons of water. this type of engine is now in current and daily use in england. m. nansouty next considers the broad gauge great western engines with ft. driving wheels. the diameters of their wheels approach those of m. estrade, and exceed considerably in size any lately proposed. m. nansouty dwells especially upon the boiler power of the great western railway, because one of the objections made to m. estrade's locomotive by the learned societies has been the difficulty of supplying boiler power enough for high speeds contemplated; and he deals at considerable length with a large number of english engines of maximum power, the dimensions and performance of which are too well known to our readers to need reproduction here. aware that a prominent weak point in m. estrade's design is that, no matter what size we make cylinders and wheels, we have ultimately to depend on the boiler for power, m. nansouty argues that m. estrade having provided more surface than is to be found in any other engine, must be successful. but the total heating surface in the engine, which we illustrate, is but , square feet, while that of the great western engines, on which he lays such stress, is , square feet, and the table which he gives of the heating surface of various english engines really means very little. it is quite true that there are no engines working in england with much over , square feet of surface, except those on the broad gauge, but it does not follow that because they manage to make an average of miles an hour that an addition of square feet would enable them to run at a speed higher by miles an hour. there are engines in france, however, which have as much as , square feet, as, for example, on the paris-orleans line, but we have never heard that these engines attain a speed of miles an hour. leaving the question of boiler power, m. nansouty goes on to consider the question of adhesion. about this he says: is the locomotive proposed by m. estrade under abnormal conditions as to weight and adhesion? this appears to have been doubted, especially taking into consideration its height and elegant appearance. we shall again reply here by figures, while remarking that the adhesion of locomotives increases with the speed, according to laws still unknown or imperfectly understood, and that consequently for extreme speeds, ignorance of the value of the coefficiency of adhesion f in the formula d i fp = . p ------- - r d renders it impossible to pronounce upon it before the trials earnestly and justly demanded by the author of this new system. in present practice f = / is admitted. m. nansouty gives in a table a _resume_ of the experience on this subject, and goes on: "the english engineers, as will be seen, make a single axle support more than tons. in france the maximum weight admitted is tons, and the constructor of the estrade locomotive has kept a little below this figure. the question of total weight appears to be secondary in a great measure, for, taking the models with uncoupled wheels, the english engines for great speed have on an average, for a smaller total weight, an adhesion equal to that of the french locomotives. the p.l.m. type of engine, which has eight wheels, four of which are coupled, throws only . tons upon the latter, being per cent. of the total weight. on the other hand, that of the english great eastern throws per cent. of the total weight on the driving wheels. numerous other examples could be cited. we cannot, we repeat, give an opinion rashly as to the calculation of adhesion for the high speed estrade locomotive before complete trials have taken place which will enable us to judge of the particular coefficients for this entirely new case." m. nansouty then goes on to consider the question of curves, and says: "it has been asked, not without reason, notably by the institution of civil engineers of paris, whether peculiar difficulties will not be met with by m. estrade's locomotive--with its three axles and large coupled wheels--in getting round curves. we have seen in the preceding tables that the driving wheels of the english locomotives with independent wheels are as much as ft. in diameter. the driving wheels of the english locomotives with four coupled wheels are ft. in diameter. m. estrade's locomotive has certainly six coupled wheels with diameters never before tried, but these six coupled wheels constitute the whole rolling length, while in the above engines a leading axle or a bogie must be taken into account, independent, it is true, but which must not be lost sight of, and which will in a great measure equalize the difficulties of passing over the curves. "is it opposed to absolute security to attack the line with driving wheels? this generally admitted principle appears to rest rather on theoretic considerations than on the results of actual experience. m. estrade, besides, sets in opposition to the disadvantages of attacking the rails with driving wheels those which ensue from the use of wheels of small diameter as liable to more wear and tear. we should further note with particular care that the leading axle of this locomotive has a certain transverse play, also that it is a driving axle. this disposition is judicious and in accordance with the best known principles." a careful perusal of m. nansouty's memoir leaves us in much doubt as to what m. estrade's views are based on. so far as we understand him, he seems to have worked on the theory that by the use of very large wheels the rolling resistance of a train can be greatly diminished. on this point, however, there is not a scrap of evidence derived from railway practice to prove that any great advantage can be gained by augmenting the diameters of wheels. in the next place, he is afraid that he will not have adhesion enough to work up all his boiler power, and, consequently, he couples his wheels, thereby greatly augmenting the resistance of the engine. he forgets that large coupled wheels were tried years ago on the great western railway, and did not answer. a single pair of drivers ft. in. in diameter would suffice to work up all the power m. estrade's boiler could supply at sixty miles an hour, much less eighty miles an hour. on the london and brighton line mr. stroudley uses with success coupled leading wheels of large diameter on his express engines, and we imagine that m. estrade's engine will get round corners safely enough, but it is not the right kind of machine for eighty miles an hour, and so he will find out as soon as a trial is made. the experiment is, however, a notable experiment, and m. estrade has our best wishes for his success.--_the engineer._ * * * * * concrete.[ ] [footnote : read july , , before the western society of engineers.] by john lundie. the subject of cement and concrete has been so well treated of in engineering literature, that to give an extended paper on the subject would be but the collection and reiteration of platitudes familiar to every engineer who has been engaged on foundation works of any magnitude. it shall therefore be the object of this communication to place before the society several notes, stated briefly and to the point, rather as a basis for discussion than as an attempt at an exhaustive treatment of the subject. concrete is simply a low grade of masonry. it is a comparatively simple matter to trace the line of continuity from heavy squared ashlar blocks down through coursed and random rubble, to grouted indiscriminate rubble, and finally to concrete. improvements in the manufacture of hydraulic cements have given an impetus to the use of concrete, but its use is by no means of recent date. it is no uncommon thing in the taking down of heavy walls several centuries old to find that the method of building was to carry up face and back with rubble and stiff mortar, and to fill the interior with bowlders and gravel, the interstices of which were filled by grouting--the whole mass becoming virtually a monolith. modern quick-setting cement accomplishes this object within a time consistent with the requirements of modern engineering works; the formation of a monolithic mass within a reasonable time and with materials requiring as little handling as possible being the desideratum. the materials of concrete as used at present are cement, sand, gravel, broken stone, and, of course, water. it is, perhaps, unnecessary to say that one of the primary requirements in materials is that they should be clean. stone should be angular, gravel well washed, sand coarse and sharp, cement fine and possessing a fair proportion of the requirements laid down in the orthodox specification. the addition of lime water, saccharated or otherwise, has been suggested as an improvement over water pure and simple, but no satisfactory experiments are on record justifying the addition of lime water. regarding the mixing of cement and lime with saccharated water, the writer made some experiments several months ago by mixing neat cement and lime with pure water and with saccharated water, with the result that the sugar proved positively detrimental to the cement, while it increased the tenacity of briquettes of lime. stone which will pass a inch is usually specified for ordinary concrete. it will be found that stone broken to this limit of size has fifty per cent. of its bulk voids. this space must be filled by mortar or preferably by gravel and mortar. if the mixing of concrete is perfect, the proportion of stone, by bulk, to other materials should be two to one. a percentage excess of other materials is, however, usually allowed to compensate for imperfection in mixing. while an excess of good mortar is not detrimental to concrete (as it will harden in course of time to equal the stone), still on the score of economy it is advisable to use gravel or a finer grade of stone in addition to the inch ring stone to fill the interstices--gravel is cheaper than cement. the statement that excess in stone will give body to concrete is a fallacy hardly worth contradicting. in short, the proportion of material should be so graded that each particle of sand should have its jacket of cement, necessitating the cement being finer than the sand (this forms the mortar); then each pebble and stone should have its jacket of mortar. the smaller the interstices between the gravel and stones, the better. the quantity of water necessary to make good concrete is a sorely debated question. the quantity necessary depends on various considerations, and will probably be different for what appears to be the same proportion of materials. it is a well known fact that brick mortar is made very soft, and bricks are often wet before being laid, while a very hard stone is usually set with very stiff mortar. so in concrete the amount of water necessarily depends, to a great extent, on the porosity or dryness of the stone and other material used. but as to using a larger or smaller quantity of water with given materials, as a matter of observation it will be found that the water should only be limited by its effect in washing away mortar from the stone. where can better concrete be found than that which has set under water? a certain definite amount of water is necessary and sufficient to hydrate the cement; less than that amount will be detrimental, while an excess can do no harm, provided, as before mentioned, that it does not wash the mortar from the stone. again, dry concrete is apt to be very porous, which in certain positions is a very grave objection to it--this, not only from the fact of its porosity, but from the liability to disintegration from water freezing in the crevices. concrete, when ready to be placed in position, should be of the consistency of a pulpy mass which will settle into place by its own weight, every crevice being naturally filled. pounding dry concrete is apt to break adjacent work, which will never again set properly. there should be no other object in pounding concrete than to assist it to settle into the place it is intended to fill. this is one of the evils concomitant with imperfection of mixing. the greater perfection of mixing attained, the nearer we get to the ideal monolith. the less handling concrete has after being mixed, the better. immediately after the mass is mixed setting commences; therefore the sooner it is in position, the more perfect will be the hardened mass; and, on the other hand, the more it is handled, the more is the process interrupted and in like degree is the finished mass deteriorated. a low drop will be found the best method of placing a batch in position. too much of a drop scatters the material and undoes the work of thorough mixing. let the mass drop and then let it alone. if of proper temper, it will find its own place with very little trimming. care should be taken to wet adjacent porous material, or the wooden form into which concrete is being placed; otherwise the water may be extracted from the concrete, to its detriment. it has been found on removing boxing that the portion adjacent to the wood was frequently friable and of poor quality, owing to the fact just stated. it is usual to face or plaster concrete work after removing the boxing. on breakwater work, where the writer was engaged, the wall was faced with cement and flint grit, and this was found to form a particularly hard and lasting protection to the face of the work. batches of concrete should be placed in position as if they were stones in block masonry, as the union of one day's work with a previous is not by any means so perfect as where one batch is placed in contact with another which has not yet set. a slope cannot be added to with the same degree of perfection that one horizontal layer can be placed on another; consequently, where work must necessarily be interrupted, it should be stepped, and not sloped off. experience in concrete work has shown that its true place is in heavy foundations, retaining walls, and such like, and then perfectly independent of other material. arches, thin walls, and such like are very questionable structures in continuous concrete, and are on record rather as failures than otherwise. this may to a certain degree be due to the high coefficient of expansion portland cement concrete has by heat. this was found by cunningham to be . of its bulk for one degree fahrenheit. it is a matter which any intelligent observer may remark, the invariable breakage of continuous concrete sidewalks, while those made in small sections remain good. this may be traced to expansion and contraction by heat, together with friction on the lower side. in foundations, according to the same authority above quoted, properly made portland cement concrete may be trusted with a safe load of tons per square foot. in large masses concrete should be worked continuously, while in small masses it should be moulded in small sections, which should be independent of each other and simply form artificial stones. the facility with which concrete can be used in founding under water renders it particularly suitable for subaqueous structures. the method of dropping it from hopper barges in masses of tons at a time, inclosed in a bag of coarse stuff, has been successfully employed by dyce cay and others. this can be carried on till the concrete appears above water, when the ordinary method of boxing can be employed to complete the work. this method was employed in the north pier breakwater at aberdeen, the breakwater being founded on the sand, with a very broad base. the advantage of bags is apparent in the leveling off of an uneven foundation. in breakwater works on the tay, in scotland, where the writer was engaged, large blocks perforated vertically were employed. these were constructed below high water mark, and an air tight cover placed over them. they were lifted by pontoons as the tide rose, and conveyed to and deposited in place, the hollows being filled with air, serving to give buoyancy to the mass. after placing in position the vertical hollows were filled with concrete, so binding the whole together--they being placed vertically over each other. as mentioned before, continuous stretches of concrete in small sections should be guarded against, owing to expansion by heat; but the fact of a few cracks appearing in heavy masses of concrete should not cause apprehension. these occur from unequal settlement and other causes. they should continue to be carefully grouted and faced until settlement is complete. the use of concrete is becoming more and more general for foundation works. the desideratum hitherto has been a perfect and at the same time an economical mixer. concrete can be mixed by hand and the materials well incorporated, but this is an expensive and man-killing method, as the handling of the wet mass by the shovel is extremely hard work, besides which the slowness of the method allows part of a large batch to set before the other is mixed, so that small batches, with attendant extra handling, are necessary to make a good job. mixers with a multiplicity of knives to toss the material have been used, but with little economical success. of simple conveyers, such as a worm screw, little need be said; they are not mixers, and it seems a positive waste of time to pass material through a machine when it comes out in little better shape than it is put in. a box of the shape of a barrel has been used, it being trunnioned at the sides. the objection to this is that the material is thrown from side to side as a mass, there being a waste of energy in throwing about the material in mass without accomplishing an equivalent amount of mixing. then a rectangular box has been used, trunnioned at opposite corners; but here the grave objection is that the concrete collects in the corners, and after a few turns it requires cleaning out, the material so sticking in the corners that it gets clogged up and ceases to mix. the writer has just protected by letters patent a machine, in devising which the following objects were borne in mind: st. that every motion of the machine should do some useful work. hitherto box or barrel mixers have gone on the principle of throwing the material about indiscriminately, expecting that somehow or other it would get mixed. d. that the sticking of the material anywhere within the mixer should be obviated. d. that an easy discharge should be obtained. th. that the water should be introduced while the mixer revolves. with these desiderata in view, a box was designed which in half a turn gathers the material, then spreads it, and throws it from one side to the other at the same time that water is being introduced through a hollow trunnion. it is also so constructed that all the sides slope steeply toward the discharge, and there is not a rectangular or acute angle within the box. a machine has now been worked steadily for several weeks, putting in the concrete in the foundations of the new jackson street bridge in this city, by general fitz-simons. the result exceeds expectations. the concrete is perfectly mixed, the discharge is simple, complete and effective, and at the same time the cost of labor in mixing and placing in position is lessened by per cent. as compared with any known to have been put in under similar circumstances.--_jour. association of engineering societies._ * * * * * machine designing.[ ] [footnote : a lecture delivered before the franklin institute, philadelphia, monday, jan. , . from the journal of the institute.] by john e. sweet. "carrying coals to newcastle," the oft quoted comparison, fittingly indicates the position i place myself in when attempting to address members of this institute on the subject of machine designing. philadelphia, the birthplace of the great and nearly all the good work in this, the noblest of all industrial arts, needs no help or praise at my hands, but i hope her sons may be prevailed upon to do in their right way what i shall try to do roughly--that is, formulate some rules or establish principles by which we, who are not endowed with genius, may so gauge our work as to avoid doing that which is truly bad. no great author was ever made by studying grammar, rhetoric, language, history, or by imitating some other author, however great. neither has there ever been any great poet or artist produced by training. but there are many writers who are not great authors, many rhymsters who are not poets, and many painters who are not artists; and while training will not make great men of them, it will help them to avoid doing that which is absolutely bad, and so may it not be with machine designing? if there are among you some who have a genius for it, what i shall have to say will do you no good, for genius needs no rules, no laws, no help, no training, and the sooner you let what i have to say pass from your minds, the better. rules only hamper the man of genius; but for us, who either from choice or necessity work away at machine designing without the gift, cannot some simple ruling facts be determined and rules formulated or principles laid down by which we can determine what is really good, and what bad? one of the most important and one of the first things in the construction of a building is the foundation, and the laws which govern its construction can be stated in a breath, and ought to be understood by every one. assuming the ground upon which a building is to be built to be of uniform density, _the width_ of the foundation should be in proportion to the load, the foundation should taper equally on each side, and the center of the foundation should be under the center of pressure. in other words, it is as fatal to success to have too much foundation under the light load as it is too little under a heavy one. cannot we analyze causes and effects, cost and requirements, so as to formulate some simple laws similar to the above by which we shall be able to determine what is a good and what a bad arrangement of machinery, foundation, framing or supports? a vast amount of work is expended to make machines true, and the machines, or a large majority of them, are expected to produce true work of some kind in turn. then, if this be admitted, cannot the following law be established, that every machine should be so designed and constructed that when once made true it will so remain, regardless of wear and all external influences to which it is liable to be subjected? one tool maker says that it is right, and another that it cannot be done. no matter whether it can or cannot, is it not the thing wanted, and if so, is it not an object worth striving for? one tool maker says that all machine tools, engines, and machinery should set on solid stone foundations. should they? they do not always, for in substantial philadelphia some machine tools used by machine builders stand upon second floors, or, perhaps, higher up. and of these machine tools none, or few at least, except those mounted upon a single pedestal, are free from detrimental torsion where the floor upon which they rest is distorted by unequal loading. but, to first consider those of such magnitude as to render it absolutely necessary to erect them--not rest them--on masonry, is due consideration always taken to arrange an unequal foundation to support the unequal loads?--and they cannot be expected to remain true if not. when one has the good fortune to have a machine to design of such extent that the masonry becomes the main part of it, what part of the glory does he give to the mason? is the masonry part of it always satisfactory, and is not this resorting to the mason for a frame rather than a support adopted on smaller machines than is necessary? is it necessary even in a planing machine of forty feet length of bed and a thirty foot table? could not the bed be cast in three pieces, the center a rectangular box, or or feet square, feet long, with internal end flanges, ways planed on its upper surface, and ends squared off, a monster, perhaps, but if our civil engineers wanted such a casting for a bridge, they'd get it. add to this central section two bevel pieces of half the length, and set the whole down through the floor where your masonry would have been and rest the whole on two cross walls, and you would have a structure that if once made true would remain so regardless of external influences. cost? yes; and so do frodsham watches--more than "waterbury." it may be claimed, in fact, i have seen lathes resting on six and eight feet, engines on ten, and a planing machine on a dozen. do they remain true? sometimes they do, and many times they do not. is the principle right? not when it can be avoided; and when it cannot be avoided, the true principle of foundation building should be employed.... a strange example of depending on the stone foundation for not simply support, but to resist strain, may be found in the machines used for beveling the edges of boiler plate. not so particularly strange that the first one might have, like topsy, "growed," but strange because each builder copies the original. you will remember it, a complete machine set upon a stone foundation, to straighten and hold a plate, and another complete machine set down by the side of it and bolted to the same stone to plane off the edge; a lot of wasted material and a lot of wasted genius, it always seems to me. going around robin hood's barn is the old comparison. why not hook the tool carriage on the side of the clamping structure, and thus dispense with one of the frames altogether? many of the modern builders of what chordal calls the hyphen corliss engine claim to have made a great advance by putting a post under the center of the frame, but whether in acknowledgment that the frame would be likely to go down or the stonework come up i could never make out. what i should fear would be that the stone would come up and take the frame with it. every brick mason knows better than to bed mortar under the center of a window sill; and this putting a prop under the center of an engine girder seems a parallel case. they say mr. corliss would have done the same thing if he had thought of it. i do not believe it. if mr. corliss had found his frames too weak, he would soon have found a way to make them stronger. john richards, once a resident of this city, and likely the best designer of wood-working machinery this country, if not the world, ever saw, pointed out in some of his letters the true form for constructing machine framing, and in a way that it had never been forced on my mind before. as dozens, yes, hundreds, of new designs have been brought out by machine tool makers and engine builders since john richards made a convert of me, without any one else, so far as i know, having applied the principle in its broadest sense, i hope to present the case to you in a material form, in the hope that it may be more thoroughly appreciated. the usual form of lathe and planer beds or frames is two side plates and a lot of cross girts; their duty is to guide the carriages or tables in straight lines and carry loads resisting bending and torsional strains. if a designer desires to make his lathe frame stronger than the other fellows, he thinks, if he thinks at all, that he will put in more iron, rather than, as he ought to think, how shall i distribute the iron so it will do the most good? in illustration of this peculiar way of doing things, which is not wholly confined to machine designers, i should like to relate a story, and as i had to carry the large end of the joke, it may do for me to tell it. while occupying a prominent position, and yet compelled to carry my dinner, my wife thought the common dinner pail, with which you are probably familiar (by sight, of course), was not quite the thing for a professor (even by brevet) to be seen carrying through the streets. so she interviewed the tinsmith to see if he could not get up something a little more tony than the regulation fifty-cent sort. oh, yes; he could do that very nicely. how much would the best one he could make cost? well, if she could stand the racket, he could make one worth a dollar. she thought she could, and the pail was ordered, made, and delivered with pride. perhaps you can guess the result. a facsimile of the original, only twice the size. now, this is a very fair illustration of the fallacy of making things stronger by simply adding iron. to illustrate what i think a much better way, i have had made these crude models (see fig. ), for the full force of which, as i said before, i am indebted to john richards; and i would here add that the mechanic who has never learned anything from john richards is either a very good or very poor one, or has never read what john richards has written or heard what he has had to say. three models, as shown in fig. , were exhibited; all were of the same general dimensions and containing the same amount of material. the one made on the box principle, c, proved to be fifty per cent. stiffer in a vertical direction than either a or b, from twenty to fifty times stiffer sidewise, and thirteen times more rigid against torsion than either of the others. however strong a frame may be, its own weight and the weight of the work upon it tends to spring it unless evenly distributed, and to twist it unless evenly proportioned. for all small machines the single post obviates all trouble, but for machine tools of from twice to a half dozen times their own length the single post is not available. four legs are used for machines up to ten feet or so, and above that legs various and then solid masonry. if the four legs were always set upon solid masonry, and leveled perfectly when set, no question could be raised against the usual arrangement, unless it be this: ought they not to be set nearly one-fourth the way from the end of the bed? or to put it in another form: will not the bed of an iron planing machine twelve feet in length be equally as well supported by four legs if each pair is set three feet from the ends--that is, six feet apart--as by six legs, two pairs at the ends and one in the center, and the pairs six feet apart? there being six feet of unsupported bed in either case, with this advantage in favor of the four over the six, settling of the foundation would not bend the bed. it is not likely that one-half of the four-legged machine tools used in this country are resting upon stable foundations, nor that they ever will be; and while this is a fact, it must also remain a fact that they should be built so as to do their best on an unstable one. any one of the thousand iron planing machines of the country, if put in good condition and set upon the ordinary wood floors, may be made to plane work winding in either direction by shifting a moving load of a few hundred pounds on the floor from one corner of the machine to the other, and the ways of the ordinary turning lathe may be more easily distorted still. machine tool builders do not believe this, simply because they have not tried it. that is, i suppose this must be so, for the proof is so positive, and the remedy so simple, that it does not seem possible they can know the fact and overlook it. the remedy in the case of the planer is to rest the structure on the two housings at the rear end and on a pair of legs about one-fourth of the way back from the front, pivoted to the bed on a single bolt as near the top as possible. [illustration: a, b, c, fig. , illustrate the models shown by mr. sweet, which represented three forms of lathe and planer construction. the box form, c, proved to be fifty per cent. stronger in its vertical direction than either a or b, fifty times stronger sideways than a and twenty times stronger than b, and more than thirteen times stronger than either when subject to torsional strain. a, fig. , represents an ordinary pinion tooth, and b shows one of the same size strengthened by cutting put metal at the root; c and d were models showing the same width of teeth extended to six times the length, showing what would be their character if considered as springs. ] a similar arrangement applies to the lathe and machine tools of that character--that is, machines of considerable length in proportion to their width, and with beds made sufficiently strong within themselves to resist all bending and torsional strains, fill the requirements so far as all except wear is concerned. that is, if the frames are once made true, they will remain so, regardless of all external influences that can be reasonably anticipated. among wood-working machines there are many that cannot be built on the single rectangular box plan--rested on three points of support. fortunately, the requirements are not such as demand absolute straight and flat work, because in part from the fact that the material dealt with will not remain straight and flat even if once made so, and in the design of wood-working machinery it is of more importance to so design that one section or element shall remain true within itself, than that the various elements should remain true with one another. the lathe, the planing machine, the drilling machine, and many others of the now standard machine tools will never be superseded, and will for a long time to come remain subjects of alteration and attempted improvement in every detail. the head stock of a lathe--the back gear in particular--is about as hard a thing to improve as the link motion of a locomotive. some arrangement by which a single motion would change from fast to slow, and a substitute for the flanges on the pulleys, which are intended to keep the belt out of the gear, but never do, might be improvements. if the flanges were cast on the head stock itself, and stand still, rather than on the pulley, where they keep turning, the belt would keep out from between the gear for a certainty. one motion should fasten a foot stock, and as secure as it is possible to secure it, and a single motion free it so it could be moved from end to end of the bed. the reason any lathe takes more than a single motion is because of elasticity in the parts, imperfection in the planing, and from another cause, infinitely greater than the others, the swinging of the hold-down bolts. should not the propelling powers of a lathe slide be as near the point of greatest resistance as possible, as is the case in a sellers lathe, and the guiding ways as close to the greatest resistance and propelling power as possible, and all other necessary guiding surfaces made to run as free as possible? a common expression to be found among the description of new lathes is the one that says "the carriage has a long bearing on the ways." long is a relative word, and the only place i have seen any long slides among the lathes in the market is in the advertisements. but if any one has the courage to make a long one, they will need something besides material to make a success of it. it needs only that the guiding side that should be long, and that must be as rigid as possible--nothing short of casting the apron in the same piece will be strong enough, because with a long, elastic guide heavy work will spring it down and wear it away at the center, and then with light work it will ride at the ends, with a chattering cut as a consequence. an almost endless and likely profitless discussion has been indulged in as to the proper way to guide a slide rest, and different opinions exist. it is a question that, so far as principle is concerned, there ought to be some way to settle which should not only govern the question in regard to the slide rest of a lathe, but all slides that work against a torsional resistance, as it may be called--that is, a resistance that does not directly oppose the propelling power. in other words, in a lathe the cutting point of the tool is not in line with the lead screw or rack, and a twisting strain has to be resisted by the slides, whereas in an upright drill the sliding sleeve is directly over and in line with the drill, and subject to no side strain. does not the foregoing statement that "the propelling power should be as near the resistance as possible, and the guide be as near in line with the two as possible," embody the true principle? neither of the two methods in common use meets this requirement to its fullest extent. the two-v new england plan seems like sending two men to do what one can do much better alone; and the inconsistency of guiding by the back edge of a flat bed is prominently shown by considering what the result would be if carried to an extreme. if a slide such as is used on a twenty inch lathe were placed upon a bed or shears twenty feet wide, it would work badly, and that which is bad when carried to an extreme cannot well be less than half bad when carried half way. the ease with which a cast iron bar can be sprung is many times overlooked. there is another peculiarity about cast iron, and likely other metals, which an exaggerated example renders more apparent than can be done by direct statement. cast iron, when subject to a bending strain, acts like a stiff spring, but when subject to compression it dents like a plastic substance. what i mean is this: if some plastic substance, say a thick coating of mud in the street, be leveled off true, and a board be laid upon it, it will fit, but if two heavy weights be placed on the ends, the center will be thrown up in the air far away from the mud; so, too, will the same thing occur if a perfectly straight bar of cast iron be placed on a perfectly straight planer bed--the two will fit; but when the ends of the bar are bolted down, the center of the bar will be up to a surprising degree. and so with sliding surfaces when working on oil. if to any extent elastic, they will, when unequally loaded, settle through the oil where the load exists and spring away where it is not. the tool post or tool holder that permits of a tool being raised or lowered and turned around after the tool is set, without any sacrifice of absolute stability, will be better than one in which either one of these features is sacrificed. handiness becomes the more desirable as the machines are smaller, but handiness is not to be despised even in a large machine, except where solidity is sacrificed to obtain it. the weak point in nearly all (and so nearly all that i feel pretty safe in saying all) small planing machines is their absolute weakness as regards their ability to resist torsional strain in the bed, and both torsional and bending strain in the table. is it an uncommon thing to see the ways of a planer that has run any length of time cut? in fact, is it not a pretty difficult thing to find one that is not cut, and is this because they are overloaded? not at all. figure up at even fifty pounds to the square inch of wearing surface what any planer ought to carry, and you will find that it is not from overloading. twist the bed upon the floor (and any of them will twist as easy as two basswood boards), and your table will rest the hardest on two corners. strap, or bolt, or wedge a casting upon the table, or tighten up a piece between a pair of centers eight or ten inches above the table, and bend the table to an extent only equal to the thickness of the film of oil between the surface of the ways, and the large wearing surface is reduced to two wearing points. in designing it should always be kept in mind, or, in fact, it is found many times to be the correct thing to do, to consider the piece as a stiff spring, and the stiffer the better. the tooth of a gear wheel is a cast iron spring, and if only treated as would be a spring, many less would be broken. a point in evidence: the pinions in a train of rolls, which compel the two or more rolls to travel in unison, are necessarily about as small at the pitch line as the rolls themselves; they are subject to considerable strain and a terrible hammering by back lash, and break discouragingly frequent, or do when made of cast iron, if not of very coarse pitch, that is, with very few teeth--eleven or twelve sometimes. in a certain case it became desirable to increase the number of teeth, when it was found that the breakages occurred about as the square root of their number. when the form was changed by cutting out at the root in this form (fig. ), the breakage ceased. a, fig. , shows an ordinary gear tooth, and b the form as changed; c and d show the two forms of the same width, but increased to six times the length. if the two are considered as springs, it will be seen that d is much less likely to be broken by a blow or strain. the remedy for the flimsy bed is the box section; the remedy for the flimsy planer table is the deep box section, and with this advantage, that the upper edge can be made to shelve over above the reversing dogs to the full width between the housings. the parabolic form of housing is elegant in appearance, but theoretically right only when of uniform cross section. in some of the counterfeit sort the designers seem to have seen the original sellers, remembering the form just well enough to have got the curve wrong end up, and knowing nothing of the principle, have succeeded in building a housing that is absolutely weak and absolutely ugly, with just enough of the original left to show from where it was stolen. if the housing is constructed on the brace plan, should not the braces be straight, as in the old bement, and the center line of strain pass through the center line of the brace? if the housing is to take the form of a curve, the section should be practically uniform, and the curve drawn by an artist. many times housings are quite rigid enough in the direction of the travel of the table, but weak against side pressure. the hollow box section, with secure attachment to the bed and a deep cross beam at the top, are the remedies. raising and lowering cross heads, large and small, by two screws is a slow and laborious job, and slow when done by power. counterweights just balancing the cross head, with metal straps rather than chains or ropes, large wheels with small anti-friction journals, and the cross head guarded by one post only, changes a slow to a quick arrangement, and a task to a comfort. housings of the hollow box section furnish an excellent place for the counterweights. the moving head, which is not expected to move while under pressure, seems to have settled into one form, and when hooked over a square ledge at the top, a pretty satisfactory form, too. but in other machines built in the form of planing machines, in which the head is traversed while cutting, as is the case with the profiling machine, the planer head form is not right. both the propelling screw, or whatever gives the side motion, should be as low down as possible, as should also be the guide. there is a principle underlying the sellers method of driving a planer table that may be utilized in many ways. the endurance goes far beyond any man's original expectations, and the explanation, very likely, lies in the fact that the point of contact is always changing. to apply the same principle to a common worm gear it is only necessary to use a worm in a plain spur gear, with the teeth cut at an angle the wrong way, and set the worm shaft at an angle double the amount, rather than at °. such a worm gear will, i fancy, outwear a dozen of the scientific sort. it would likely be found a convenience to have the head of a planing machine traverse by a handle or crank attached to itself, so it could be operated like the slide rest of a lathe, rather than as is now the case from the end of the cross head. the principle should be to have things convenient, even at an additional cost. anything more than a single motion to lock the cross head to the housing or stanchions should not be countenanced in small planers at least. many of the inferior machines show marked improvements over the better sorts, so far as handiness goes, while there is nothing to hinder the handy from being good and the good handy. when we consider that since the post-drilling machine first made its appearance, there have been added blasdell's quick return, the automatic feed, belt-driven spindles, back gears placed where they ought to be, with many minor improvements, it is not safe to assume that the end has been reached; and when we consider that as a piece of machine designing, considered in an artistic sense entirely, the bement post drill is the finest the world ever saw (the porter-allen engine not excepted, which is saying a good deal), is it not strange that of all mechanical designs none other has taken on such outrageous forms as this? one thing that would seem to be desirable, and that ordinary skill might devise, is some sort of snap clutch by which the main spindle could be stopped instantly by touching a trigger with the foot; many drills and accidents would be saved thereby. of the many special devices i have seen for use on a drilling machine, one used by mr. lipe might be made of universal use. it is in the form of a bracket or knee adjustably attached to the post, which has in its upper surface a v into which round pieces of almost any size can be fastened, so that the drill will pass through it diametrically. it is not only useful in making holes through round bars, but straight through bosses and collars as well. the radial drill has got so it points its nose in all directions but skyward, but whether in its best form is not certain. the handle of the belt shipper, in none that i have seen, follows around within reach of the drill as conveniently as one would like. as the one suggestion i have to make in regard to the shaping machine best illustrates the subject of maintaining true wearing surfaces, i will leave it until i reach that part of my paper. (_to be continued._) * * * * * the mechanics of a liquid. a liquid comes in handy sometimes in measuring the volume of a substance where the length, breadth, and thickness is difficult to get at. it is a very simple operation, only requiring the material to be plunged under water and measure the amount of displacement by giving close attention to the overflow. it is a process that was first brought into use in the days when jewelers and silversmiths were inclined to be a little dishonest and to make the most of their earnings out of the rule of their country. if we remember rightly, the voice of some one crying "eureka" was heard about that time from somebody who had been taking a bath up in the country some two miles from home. tradition would have us believe that the inventor left for the patent office long before his bathing exercises were half through with, and that he did the most of his traveling at a lively rate while on foot, but it is more reasonable to suppose that bath tubs were in use in those days, and that he noticed, as every good philosopher should, that his bathing solution was running over the edge of the tub as fast as his body sunk below the surface. taking to the heels is something that we hear of even at this late day. [illustration] it was not many years ago that an inventor of a siphon noticed how water could be drawn up hill with a lamp wick, and the thought struck him that with a soaking arrangement of this kind in one leg of the siphon a flow of water could be obtained that would always be kept in motion. without taking a second thought he dropped his work in the hay field, and ran all the way to london, a distance of twenty miles, to lay his scheme before a learned man of science. he must have felt like being carried home on a stretcher when he learned that a performance of this kind was a failure. among the others who have given an exhibition of this kind we notice an observer who was more successful. being an overseer in a cotton mill, he had only to run over to his dining room and secure two empty fruit jars and pipe them up, as shown. he had had trouble in measuring volume by the liquid process by having everything he attempted to measure get a thorough wetting, and there were many substances that were to be experimented upon that would not stand this part of the operation, such as fibers and a number of pulverized materials. one of the jars was packed in tight, nearly half full of cotton, and the other left entirely empty. the question now is to measure the volume of cotton without bringing any of the fibers in contact with the water. the liquid is poured into the tunnel in the upright tube under head enough to partially fill the jars when the overflow that stands on a level with the line, d e, is open to allow the air in each jar to adjust itself as the straight portions are wanted to work from. the overflow is then closed and head enough of water put on to compress the air in the empty jar down into half its volume. it may take a pipe long enough to reach up into the second story, but it need not be a large one, and pipes round a cotton mill are plentiful. in the jar containing cotton the water has not risen so high, there being not so much air to compress, and comes to rest on the line, c. now we have this simple condition to work from. if the water has risen so as to occupy half of the space that has been taken up by the amount of air in one jar, it must have done the same in the other, and if it could have been carried to twice the extent in volume would reach the bottom of the jar in the one containing nothing but air, and to the line, h i, in the jar containing cotton. the fibers then must have had an amount of material substance about them to fill the remaining space entirely full, so that a particle of air could not be taken into account anywhere. the cotton has produced the same effect that a solid substance would do if it just filled the space shown above the line, h i, for the water has risen into half the space that is left below it. this enables an overseer to look into the material substance of textile fibers by bringing into use the elasticity of atmospheric air, reserving the liquid process for measuring volume to govern the amount of compressibility.--_boston journal of commerce._ * * * * * volute double distilling condenser. this distiller and condenser which we illustrate has been designed, says _engineering_, for the purpose of obtaining fresh water from sea water. it is very compact, and the various details in connection with it may be described as follows: steam from the boiler is admitted into the evaporator through a reducing valve at a pressure of about lb., and passing through the volute, b, evaporates the salt water contained in the chamber, c; the vapor thus generated passing through the pipe, d, into the volute condenser, e, where it is condensed. the fresh water thus obtained flows into the filter, from which it is pumped into suitable drinking tanks. [illustration: volute double distilling apparatus.] the steam from the boiler after passing through the volute, b, is conveyed by means of a pipe to the second volute, h, where it is condensed, and the water resulting is conveyed by means of a pump to the hot well or feed tank. the necessary condensing water enters at j and is discharged at k. the method of keeping the supply of salt water in the evaporator at a constant level is very efficient and ingenious. to the main circulating discharge pipe, a small pipe, l, is fitted, which is in communication with the chamber, m, and through this the circulating sea water runs back until it attains a working level in the evaporator, when a valve in the end of pipe, l, is closed by the action of the float, n, the regulation of admission being thus automatic and certain. the steam from the boiler can be regulated by means of a stop valve, and the pressure in the evaporator should not exceed lb., while the pressure gauge is so arranged that the pressure in both condenser and evaporator is shown at the same time. a safety valve is fitted at the top of the condenser, and an automatic blow-off valve, p, is arranged to blow off when a certain density of brine has been attained in the evaporator. the "esco" triple pump (fig. ), which has been specially manufactured for this purpose, has three suctions and deliveries, one for circulating water, the second for the condensed steam, and a third for the filtered drinking water, so that the latter is kept fresh and clean. the condenser and pumps are manufactured by ernest scott & co., close works, newcastle on tyne, and were shown by them at the late exhibition in their town. * * * * * improved current meter. paul kotlarewsky, of st. petersburg, has invented an instrument for measuring or ascertaining the velocity of water and air currents. upon the shaft or axis of the propeller wheel, or upon a shaft geared therewith, there is a hermetically closed tube or receptacle, d, which is placed at right angles with the shaft, and preferably so that its longitudinal axis shall intersect the axis of said shaft. in this tube or receptacle is placed a weight, such as a ball, which is free to roll or slide back and forth in the tube. the effect of this arrangement is, that as the shaft revolves, the weight will drop alternately toward opposite ends of the tube, and its stroke, as it brings up against either end, will be distinctly heard by the observer as well as felt by him if, as is usually the case, the apparatus when in use is held by him. by counting the strokes which occur during a given period of time, the number of revolutions during that period can readily be ascertained, and from that the velocity of the current to be measured can be computed in the usual way. when the apparatus is submerged in water, by a rope held by the observer, it will at once adjust itself to the direction of the current. the force of the current, acting against the wings or blades of the propeller wheel, puts the latter in revolution, and the tube, d, will be carried around, and the sliding weight, according to the position of the tube, will drop toward and bring up against alternately opposite ends of said tube, making two strokes for every revolution of the shaft. [illustration] * * * * * the flower industry of grasse. a paper on this subject was read before the chemists' assistants' association on march , by mr. f.w. warrick, and was listened to with much interest. mr. warrick first apologized for presenting a paper on such a frivolous subject to men who had shown themselves such ardent advocates of the higher pharmacy, of the "ologies" in preference to the groceries, perfumeries, and other "eries." but if perfumery could not hope to take an elevated position in the materiæ pharmaceuticæ, it might be accorded a place as an adjunct, if only on the plea that those also serve who only stand and wait. mr. warrick mentioned that his family had been connected with this industry for many years, and that for many of the facts in the paper he was indebted to a cousin who had had twenty years' practical experience in the south, and who was present that evening. grasse. the town of grasse is perhaps more celebrated than any other for its connection with the perfume industry in a province which is itself well known to be its home. this, the department of the alpes maritimes, forms the southeastern corner of france. its most prominent geographical features are an elevated mountain range, a portion of the alps, and a long seaboard washed by the mediterranean--whence the name alpes maritimes. the calcareous hills round grasse and to the north of nice are more or less bare, though they were at one time well wooded; the reafforesting of these parts has, however, made of late great progress. nearer the sea vegetation is less rare, and there many a promontory excites the just admiration of the visitor by its growth of olives, orange and lemon trees, and odoriferous shrubs. who that has ever sojourned in this province can wonder that goethe's mignon should have ardently desired a return to these sunny regions? visitors on these shores on the first day of this year found goethe's lines more poetical than true-- where a wind ever soft from the blue heaven blows, and the groves are of laurel, and myrtle, and rose; for they gathered round their fires and coughed and groaned in chorus, and entertained each other with accounts of their ailments. but this was exceptional, and the climate of the alpes maritimes is on the whole as near perfection as anything earthly can be. this, however, is not due to its latitude, but rather to its happy protection from the north by its alps and to its being bathed on the south by the warm mediterranean and the soft breezes of an eastern wind (which evidently there bears a different reputation to that which it does with us). the mistral, or cold breeze from the hills, is indeed the only climatic enemy, if we except an occasional earthquake. the town of grasse itself is situated in the southern portion of the department, and enjoys its fair share of the advantages this situation affords. it is about ten miles from cannes (lord brougham's creation), and, as the crow flies, twenty-five miles from nice, though about forty miles by rail, for the line runs down to cannes and thence along the shore to nice. built on the side of a hill some , feet above the level of the sea, the town commands magnificent views over the surrounding country, especially in the direction of the sea, which is gloriously visible. an abundant stream, the foux, issuing from the rocks just above the town, is the all productive genius of the place; it feeds a hundred fountains and as many factories, and then gives life to the neighboring fields and gardens. the population of grasse is about , , and the flora of its environs represents almost all the botany of europe. among the splendid pasture lands, , feet above the sea, are fields of lavender, thyme, etc. from , to , feet there are forests of pine and other gymnosperms. from , to , feet firs and the beech are the most prominent trees. between , and , feet we find our familiar friends the oak, the chestnut, cereals, maize, potatoes. below this is the mediterranean region. here orange, lemon, fig, and olive trees, the vine, mulberry, etc., flourish in the open as well as any number of exotics, palms, aloes, cactuses, castor oil plants, etc. it is in this region that nature with lavish hand bestows her flowers, which, unlike their compeers in other lands, are not born to waste their fragrance on the desert air or to die "like the bubble on the fountain," but rather (to paraphrase george eliot's lofty words) to die, and live again in fats and oils, made nobler by their presence. the following are the plants put under contribution by the perfume factories of the district, viz., the orange tree, bitter and sweet, the lemon, eucalyptus, myrtle, bay laurel, cherry laurel, elder; the labiates; lavender, spike, thyme, etc.; the umbelliferous fennel and parsley, the composite wormwood and tarragon, and, more delicate than these, the rose, geranium, cassie, jasmin, jonquil, mignonette, and violet. the perfume factory. in the perfume factory everything is done by steam. starting from the engine room at the bottom, the visitor next enters the receiving room, where early in the morning the chattering, patois-speaking natives come to deliver the flowers for the supply of which they have contracted. the next room is occupied with a number of steam-jacketed pans, a mill, and hydraulic presses. next comes the still room, the stills in which are all heated by steam. in the "extract" department, which is next reached, are large tinned-copper drums, fitted with stirrers, revolving in opposite directions on vertical axes. descending to the cellar--the coolest part of the building--we find the simple apparatus used in the process of enfleurage. the apparatus is of two kinds. the smaller is a frame fitted with a sheet of stout glass. a number of these, all of the same size, when placed one on the top of the other, form a tolerably air tight box. the larger is a frame fitted with wire netting, over which a piece of molleton is placed. the other rooms are used for bottling, labeling, etc. the following are some of the details of the cultivation and extraction of perfumes as given in mr. warrick's paper: orange perfumes. the orange tree is produced from the pip, which is sown in a sheltered uncovered bed. when the young plant is about feet high, it is transplanted and allowed a year to gain strength in its new surroundings. it is then grafted with shoots from the portugal or bigaradier. it requires much care in the first few years, must be well manured, and during the summer well watered, and if at all exposed must have its stem covered up with straw in winter. it is not expected to yield a crop of flowers before the fourth year after transplantation. the flowering begins toward the end of april and lasts through may to the middle of june. the buds are picked when on the point of opening by women, boys, and girls, who make use of a tripod ladder to reach them. these villagers carry the fruits (or, rather, flowers) of their day's labor to a flower agent or commissionnaire, who weighs them, spreads them out in a cool place (the flowers, not the villagers), where they remain until or a.m.; he then puts them into sacks, and delivers them at the factory before the sun has risen. they are here taken in hand at once; on exceptional days as many as tons being so treated in the whole province. after the following season, say end of june, the farmers prune their trees; these prunings are carted to the factory, where the leaves are separated and made use of. during the autumn the ground round about the trees is well weeded, dug about, and manured. the old practice of planting violets under the orange trees is being abandoned. later on in the year those blossoms which escaped extermination have developed into fruits. these, when destined for the production of the oil, are picked while green. the orange trees produce a second crop of flowers in autumn, sometimes of sufficient importance to allow of their being taken to the factories, and always of sufficient importance to provide brides with the necessary bouquets. nature having been thus assisted to deliver these, her wonderful productions, the flowers, the leaves, and the fruits of the orange tree, at the factory, man has to do the rest. he does it in the following manner: the flowers are spread out on the stone floor of the receiving room in a layer some to inches deep; they are taken in hand by young girls, who separate the sepals, which are discarded. such of the petals as are destined for the production of orange flower water and neroli are put into a still through a large canvas chute, and are covered with water, which is measured by the filling of reservoirs on the same floor. the manhole of the still is then closed, and the contents are brought to boiling point by the passage of superheated steam through the coils of a surrounding worm. the water and oil pass over, are condensed, and fall into a florentine receiver, where the oil floating on the surface remains in the flask, while the water escapes through the tube opening below. a piece of wood or cork is placed in the receiver to break up the steam flowing from the still; this gives time for the small globules of oil to cohere, while it breaks the force of the downward current, thus preventing any of the oil being carried away. the first portions of the water coming from the still are put into large tinned copper vats, capable of holding some gallons, and there stored, to be drawn off as occasion may require into glass carboys or tinned copper bottles. this water is an article of very large consumption in france; our english cooks have no idea to what an extent it is used by the _chefs_ in the land of the "darned mounseer." the oil is separated by means of a pipette, filtered, and bottled off. it forms the oil of neroli of commerce; , kilos. of the flowers yield kilo. of oil. that obtained from the flowers of the bigaradier, or bitter orange, is the finer and more expensive quality. the delicate scent of orange flowers can be preserved quite unchanged by another and more gentle process, viz., that of maceration. it was noticed by some individual, whose name has not been handed down to us, that bodies of the nature of fat and oil are absorbers of the odor-imparting particles exhaled by plants. this property was seized upon by some other genius equally unknown to fame, who utilized it to transfer the odor of flowers to alcohol. where oil is used it is the very finest olive, produced by the trees in the neighborhood. this is put into copper vats holding about gallons; cwt. of flowers is added. after some hours the flowers are strained out by means of a large tin sieve. the oil is treated with another cwt. of flowers and still another, until sufficiently impregnated. it is then filtered through paper until it becomes quite bright; lastly it is put into tins, and is ready for exportation or for use in the production of extracts. where fat is employed as the macerating agent, the fat used is a properly adjusted mixture of lard and suet, both of which have been purified and refined during the winter months, and kept stored away in well closed tins. one cwt. of the fat is melted in a steam-jacketed pan, and poured into a tinned copper vat capable of holding from to cwt. about cwt. of orange flowers being added, these are well stirred in with a wooden spatula. after standing for a few hours, which time is not sufficient for solidification to take place, the contents are poured into shallow pans and heated to ° c. the mixture thus rendered more fluid is poured on to a tin sieve; the fat passes through, the flowers remain behind. these naturally retain a large amount of macerating liquor. to save this they are packed into strong canvas bags and subjected to pressure between the plates of a powerful hydraulic press. the fat squeezed out is accompanied by the moisture of the flowers, from which it is separated by skimming. being returned to the original vat, our macerating medium receives another complement of flowers to rob of their scent, and yet others, until the strength of the pomade desired is reached. the fat is then remelted, decanted, and poured into tins or glass jars. to make the extrait, the pomade is beaten up with alcohol in a special air tight mixing machine holding some gallons, stirrers moved by steam power agitating the pomade in opposite directions. after some hours' agitation a creamy liquid is produced, which, after resting, separates, the alcohol now containing the perfume. by passing the alcohol through tubes surrounded by iced water, the greater part of the dissolved fat is removed. these are the processes applied to the flowers. the leaves are distilled only for the oil of petit grain. this name was given to the oil because it was formerly obtained from miniature orange fruits. from , kilos. of leaves kilos. of oil are obtained. the oil obtained from the fruit of the orange, like that of the lemon, is extracted at grasse by rolling the orange over the pricks of an _ecueille_, an instrument with a hollow handle, into which the oil flows. the oil is sometimes taken up by a sponge. where the oil is produced in larger quantities, as at messina, more elaborate apparatus is employed. a less fragrant oil is obtained by distilling the raspings of the rind. the eucalyptus, myrtle, etc. of later introduction than the trees of the orange family is the eucalyptus globulus, which, not being able to compete with the former in the variety of nasal titillations it gives rise to, probably consoles itself with coming off the distinct victor in the department of power and penetration. the leaves and twigs of this tree are distilled for oil. this oil is in large demand on the continent, the fact of there being no other species than the globulus in the neighborhood being a guarantee of the uniformity of the product. whereas the eucalyptus is but a newcomer in these regions, another member of the same family, the common myrtle, can date its introduction many centuries back. an oil is distilled from its leaves, and also a water. associated with the myrtle we find the leaves of the bay laurel, forming the victorious wreaths of the ancients. the oil produced is the oil of bay laurel, oil of sweet bay. this must not be confounded with the oil of bays of the west indies, the produce of the _myrcia acris_; nor yet with the cherry laurel, a member of yet another family, the leaves of which are sometimes substituted for those of the sweet bay. the leaves of this plant yield the cherry laurel water of the b.p. it can hardly be said to be an article of perfumery. it also yields an oil. another water known to the british pharmacopoeia is that produced from the flowers of the elder, which flourishes round about grasse. the rue also grows wild in these parts, and is distilled. the labiates. the family which overshadows all others in the quantity of essential oils which it puts at the disposal of the grassois and their neighbors is that of the labiatæ. foremost among these we have the lavender, spike, thyme, and rosemary. these are all of a vigorous and hardy nature and require no cultivation. the tops of these plants are generally distilled _in situ_, under contract with the grasse manufacturer, by the villagers in the immediate vicinity. the higher the altitude at which these grow, the more esteemed the oil. the finest oil of lavender is produced by distilling the flowers only. about tons of lavender, of spike, of thyme, and of rosemary are sent out from grasse every year. among the less abundant labiates of these parts is the melissa, which yields, however, a very fragrant oil. in the same family we have the sage and the sweet or common basil, also giving up their essential oils on distillation. the umbellifers. whereas the flowers of the labiate family are treated by the distillers as favorites are by the gods, and are cut off in their youth, those of the umbelliferæ are allowed to mature and develop into the oil-yielding fruits. its representatives, the fennel and parsley, grow wild round about the town, and are laid under contribution by the manufacturers. the composites are represented by the wormwood and tarragon (_estragon_). the geranium. oil of geranium is produced from the rose or oak-leaved geranium, cuttings of which are planted in well sheltered beds in october. during the winter they are covered over with straw matting. in april they are taken up, and planted in rows in fields or upon easily irrigated terraces. of water they require _quantum sufficit_; of nature's other gift, which cheers and not inebriates--the glorious sunshine--they cannot have too much. they soon grow into bushes three or four feet high. at nice they generally flower at the end of august. at grasse and cooler places they flower about the end of october. the whole flowering plant is put into the still. the rose. allied to the oil of geranium in odor are the products of the rose. the rose de provence is the variety cultivated. it is grown on gentle slopes facing the southeast. young shoots are taken from a five-year-old tree, and are planted in ground which has been well broken up to a depth of three or four feet, in rows like vines. when the young plant begins to branch out, the top of it is cut off about a foot from the ground. during the first year the farmer picks off the buds that appear, in order that the whole attention of the plant may be taken up in developing its system. in the fourth or fifth year the tree is in its full yielding condition. the flowering begins about mid-april, and lasts through may to early june. on some days as many as tons of roses are gathered in the province of the alpes maritimes. the buds on the point of opening are picked in the early morning. scott says they are "sweetest washed with morning dew." the purchaser may think otherwise where the dew has to be paid for. the flowering season over, the trees are allowed to run wild. in january they are pruned, and the branches left are entwined from tree to tree all along the line, and form impenetrable fences. a rose tree will live to a good age, but does not yield much after its seventh year. at that period it is dug up and burned, and corn, potatoes, or some other crop is grown on the land for twelve months or more. in the factory the petals are separated from the calyx, and are distilled with water for the production of rose water and the otto. for the production of the huile and pomade they are treated by maceration. they are finished off, however, by the process of enfleurage, in which the frames before alluded to are made use of. the fat, or pomade, is spread on to the glass on both sides. the blossoms are then lightly strewn on to the upper surface. a number of trays so filled are placed one on the top of the other to a convenient height, forming a tolerably air tight box. the next day the old flowers are removed, and fresh ones are substituted for them. this is repeated until the fat is sufficiently impregnated. from time to time the surface of the absorbent is renewed by serrating it with a comb-like instrument. this, of course, is necessary in order to give the hungry, non-saturated lower layers a chance of doing their duty. where oil is the absorbent, the wired frames are used in connection with cloths. the cloth acts as the holder of the oil, and the flowers are spread upon it, and the process is conducted in the same way as with the frames with glass. from the pomade the extrait de rose is made in the same way as the orange extrait. cassie. the stronger, though less delicate, cassie is grown from seeds, which are contained in pods which betray the connection of this plant with the leguminous family. after being steeped in water they are sown in a warm and well sheltered spot. when two feet high the young plant is grafted and transplanted to the open ground--ground well exposed to the sun and sheltered from the cold winds. it flourishes best in the neighborhood of grasse and cannes. the season of flowering is from october to january or february, according to the presence or absence of frost. the flowers are gathered twice a week in the daytime, and are brought to the factories in the evening. they are here subjected to maceration. jonquil. a plant of humbler growth is the jonquil. the bulbs of this are set out in rows. the flowers put in an appearance about the end of march, four or five on each stem. each flower as it blooms is picked off at the calyx. they are treated by maceration and enfleurage, chiefly the latter. the harvesting period of the jonquil is of very short duration, and it often takes two seasons for the perfumer to finish off his pomades of extra strength. the crop is also very uncertain. jasmin. a more reliable crop is that of the jasmin. this plant is reared from cuttings of the wild jasmin, which are put in the earth in rows with trenches between. level ground is chosen; if hillside only is available, this is formed into a series of terraces. when strong enough, the young stem is grafted with shoots of the _jasminum grandiflorum_. the first year it is allowed to run wild, the second it is trained by means of rods, canes and other appliances. at the approach of winter the plants are banked up with earth to half their height. the exposed parts then die off. when the last frost of winter is gone the earth is removed, and what remains of the shrub is trimmed and tidied up for the coming season. it grows to four or five feet. support is given by means of horizontal and upright poles, which join the plants of one row into a hedge-like structure. water is provided by means of the ditches already mentioned. when not used for this purpose, the trenches allow of the passage of women and children to gather the flowers. these begin to appear in sufficient quantity to repay collecting about the middle of july. the jasmin is collected as soon as possible after it blooms. this occurs in the evening, and up to about august , early enough for the blossoms to be gathered the same day. they are delivered at the factories at once, where they are put on to the chassis immediately; the work on them continuing very often till long after midnight. later on in the year they are gathered in the early morning directly the dew is off. the farmer is up betimes, and as soon as he sees the blossoms are dry he sounds a bugle (made from a sea shell) to announce the fact to those engaged to pick for him. tuberose. the tuberose is planted in rows in a similar way to the jasmin. the stems thrown up by the bulbs bear ten or twelve flowers. each flower as it blooms is picked off. the harvesting for the factories takes place from about the first week in july to the middle of october. there is an abundant yield, indeed, after this, but it is only of service to the florist, the valued scent not being present in sufficient quantity. the flowers are worked up at the factory directly they arrive by the enfleurage process. mignonette. the _reseda_, or mignonette, is planted from seed, as here in england. the flowering tops are used to produce the huile or pomade. violets. last in order and least in size comes the violet. for "the flower of sweetest smell is shy and lowly," and has taken a modest place in the paper. violets are planted out in october or april. october is preferred, as it is the rainy season; nor are the young plants then exposed to the heat of the sun or to the drought, as they would be if starting life in april. the best place for them is in olive or orange groves, where they are protected from the too powerful rays of the sun in summer and from the extreme cold in winter. specks of violets appear during november. by december the green is quite overshadowed, and the whole plantation appears of one glorious hue. for the leaves, having developed sufficiently for the maintenance of the plant, rest on their oars, and seem to take a silent pleasure in seeing the young buds they have protected shoot past them and blossom in the open. the flowers are picked twice a week; they lose both color and flavor if they are allowed to remain too long upon the plant. they are gathered in the morning, and delivered at the factories by the commissionnaires or agents in the afternoon, when they are taken in hand at once. the products yielded by this flower are prized before all others in the realms of perfumery, and cannot be improved; for, as one great authority on all matters has said: "to throw a perfume on the violet ... were wasteful and ridiculous excess." * * * * * how to make photo. printing plates. the drawing intended for reproduction is pinned on a board and placed squarely before a copying camera in a good, even light. the lens used for this purpose must be capable of giving a perfectly sharp picture right up to the edges, and must be of the class called rectilinear, i.e., giving straight lines. the picture is then accurately focused and brought to the required size. a plate is prepared in the dark room by the collodion process, which is then exposed in the camera for the proper time and developed in the ordinary way. after development, the plate is fixed and strongly intensified, in order to render the white portions of the drawings as opaque as possible. on looking through a properly treated negative of this kind, it will be seen that the parts representing the lines and black portions of the drawing are clear glass, and the whites representing the paper a dense black. the negative, after drying, is ready for the next operation, i.e., printing upon zinc. this is done in several ways. one method will, however, be sufficient for the purpose here. i obtain a piece of the bichromatized gelatine paper previously mentioned, and place it on the face of the negative in a printing frame. this is exposed to sunlight (if there is any) or daylight for a period varying from five to thirty minutes, according to the strength of the light. this exposed piece of paper is then covered all over with a thin coating of printing ink, and wetted in a bath of cold water. in a few minutes the ink leaves the white or protected parts of the paper, remaining only on the lines where the light has passed through the negative and affected the gelatine. we now have a transcript of the drawing in printing ink, on a paper which, as soon as dry, is ready for laying down on a piece of perfectly clean zinc, and passing through a press. the effect and purpose of passing this cleaned sheet of zinc through the press in contact with the picture on the gelatine paper is this: owing to the stronger attraction of the greasy ink for the clean metal than for the gelatine, it leaves its original support, and attaches itself strongly to the zinc, giving a beautifully sharp and clean impression of our original drawing in greasy ink on the surface of the zinc. the zinc plate is next damped and carefully rolled up with a roller charged with more printing ink, and the image is thus made strong enough to resist the first etching. this etching is done in a shallow bath, which is so arranged that it can be rocked to and fro. for the first etching, very weak solution of nitric acid and water is used. the plate is placed with this acid solution in the bath, and steadily rocked for five or ten minutes. the plate is then taken out, washed, and again inked; then it is dusted over with powdered resin, which sticks to the ink on the plate. after this the plate is heated until the ink and resin on the lines melt together and form a strong acid-resisting varnish over all the work. the plate is again put into the acid etching bath and further etched. these operations are repeated five or six times, until the zinc of the unprotected or white part of the picture is etched deep enough to allow the lines to be printed clean in a press, like ordinary type or an engraved wood block. i ought perhaps to explain that between each etching the plate is thoroughly inked, and that this ink is melted down the sides of the line, so as to protect the sides as well as the top from the action of the acid; were this neglected, the acid would soon eat out the lines from below. the greatest skill and care is, therefore, necessary in this work, especially so in the case of some of the exquisitely fine blocks which are etched for some art publications. there are many details which are necessary to successful etching, but those now given will be sufficient to convey to you generally the method of making the zinc plate for the typographic block. after etching there only remains the trimming of the zinc, a little touching up, and mounting it on a block of mahogany or cherry of exact thickness to render it type high, and it is now ready for insertion with type in the printer's form. from a properly etched plate hundreds of thousands of prints may be obtained, or it may be electrotyped or stereotyped and multiplied indefinitely.--_g.s. waterlow, brit. jour. photo._ * * * * * analysis of a hand fire grenade. by chas. catlett and r.c. price. the analyses of several of these "fire extinguishers" have been published, showing that they are composed essentially of an aqueous solution of one or more of the following bodies; sodium, potassium, ammonium, and calcium chlorides and sulphates, and in small amount borax and sodium acetate; while their power of extinguishing fire is but three or fourfold that of water. one of these grenades of a popular brand of which i have not found an analysis was examined by mr. catlett with the following results: the blue corked flask was so open as to show that it contained no gas under pressure, and upon warming its contents, but or cubic inches of a gas were given off. the grenade contained about c.c. of a neutral solution, which gave on analysis: in c.c. in the flask. grammes. grains. calcium chloride¹ . . magnesium " . . sodium " . . potassium " . . ------ ------ . . ¹trace of bromide. as this mixture of substances naturally suggested the composition of the "mother liquors" from salt brines, mr. price made an analysis of such a sample of "bittern" from the snow hill furnace, kanawha co., w.va., obtaining the following composition: in c.c. in c.c. grammes. grains. calcium chloride¹ . . magnesium " . . strontium " . . sodium " . . potassium " . . ------ ------ . . ¹trace of bromide. there is of course some variation in the bittern obtained from different brines, but it appears of interest to call attention to this correspondence in composition, as indicating that the liquid for filling such grenades is obtained by adding two volumes of water to one of the "bittern." the latter statement is fairly proved by the presence of the bromine, and certainly from an economical standpoint such should be its method of manufacture.--_amer. chem. jour._ * * * * * molecular weights. a new and most valuable method of determining the molecular weights of non-volatile as well as volatile substances has just been brought into prominence by prof. victor meyer (_berichte_, , no. ). the method itself was discovered by m. raoult, and finally perfected by him in , but up to the present has been but little utilized by chemists. it will be remembered that prof. meyer has recently discovered two isomeric series of derivatives of benzil, differing only in the position of the various groups in space. if each couple of isomers possess the same molecular weight, a certain modification of the new van't hoff-wislicenus theory as to the position of atoms in space is rendered necessary; but if the two are polymers, one having a molecular weight n times that of the other, then the theory in its present form will still hold. hence it was imperative to determine without doubt the molecular weight of some two typical isomers. but the compounds in question are not volatile, so that vapor density determinations were out of the question. in this difficulty prof. meyer has tested the discovery of m. raoult upon a number of compounds of known molecular weights, and found it perfectly reliable and easy of application. the method depends upon the lowering of the solidifying point of a solvent, such as water, benzine, or glacial acetic acid, by the introduction of a given weight of the substance whose molecular weight is to be determined. the amount by which the solidifying point is lowered is connected with the molecular weight, m, by the following extremely simple formula: m = t x (p / c); where c represents the amount by which the point of congelation is lowered, p the weight of anhydrous substance dissolved in grammes of the solvent, and t a constant for the same solvent readily determined from volatile substances whose molecular weights are well known. on applying this law to the case of two isomeric benzil derivatives, the molecular weights were found, as expected, to be identical, and not multiples; hence prof. meyer is perfectly justified in introducing the necessary modification in the "position in space" theory. now that this generalization of raoult is placed upon a secure basis, it takes its well merited rank along with that of dulong and petit as a most valuable means of checking molecular weights, especially in determining which of two or more possible values expresses the truth.--_nature._ * * * * * [continued from supplement, no. , page .] the direct optical projection of electro-dynamic lines of force and other electro-dynamic phenomena.[ ] [footnote : an expansion of two papers read before the a.a.a.s. at the ann arbor meeting.] by prof. j.w. moore. ii. loops. if the wire, with its lines of force, be bent into the form of a vertical circle - / in. in diameter, and fixed in a glass plate, some of the lines of force will be seen parallel to the axis of the circle. if the loop is horizontal, the lines become points. [illustration: fig. .] [illustration: fig. a.] fields of loops and magnets. place now a vertical loop opposite to the pole of a short bar magnet cemented to the glass plate with the n pole facing it. if the current passes in one direction the field will be as represented by fig. b; if it is reversed by the commutator, fig. c is an image of the spectrum. applying faraday's second principle, it appears that attraction results in the first case, and repulsion in the second. the usual method of stating the fact is, that if you face the loop and the current circulates from left over to right, the n end of the needle will be drawn into the loop. [illustration: fig. b.] [illustration: fig. c.] it thus becomes evident that the loop is equivalent to a flat steel plate, one surface of which is n and the other s. facing the loop if the current is right handed, the s side is toward you. to show the actual attraction and repulsion of a magnet by a "magnetic shell." produce the field as before (fig. ), carry a suspended magnetic needle over the field. it will tend to place itself parallel to the lines of force, with the n pole in such a position that, if the current passes clockwise as you look upon the plane of the loop, it will be drawn into the loop. reversing the position of the needle or of current will show repulsion. clerk maxwell's method of stating the fact is that "every portion of the circuit is acted on by a force urging it across the lines of magnetic induction, so as to include a greater number of these lines within the embrace of the circuit."[ ] [footnote : electricity and magnetism, maxwell, p. , §§ , .] if the horizontal loop is used (fig. a), the needle tries to assume a vertical position, with the n or s end down, according to the direction of the current. if it is desired to show that if the magnet is fixed and the loop free, the loop will be attracted or repelled, a special support is needed. [illustration: fig. ] a strip (fig. ) of brass, j, having two iron mercury cups, k_{ } k_{ }, screwed near the ends, one insulated from the strip, is fastened upon the horizontal arm of the ring support, fig. , already described. the cups may be given a slight vertical motion for accurate adjustment. small conductors (figs. , , ), which are circles, rectangles, solenoids, etc., may be suspended from the top of the plate by unspun silk, with the ends dipping into the mercury. the apparatus is therefore an ampere's stand, with the weight of the movable circuit supported by silk and with means of adjusting the contacts. the rectangles or circles are about two inches in their extreme dimension. horizontal and vertical astatic system are also used--figs. , a. the apparatus may be used with either the horizontal or vertical lantern. [illustration: fig. . fig. .] [illustration: fig. . fig. a.] if the rectangle or circle is suspended and a magnet brought near it when the current passes, the loop will be attracted or repelled, as the law requires. the experiments usually performed with de la rive's floating battery may be exhibited. the great similarity between the loop and the magnet may be shown by comparing the fields above (figs. b, c) with the actual fields of two bar magnets, figs. , a. it will be noticed that the lines in fig. , where unlike poles are opposite, are gathered together as in fig. b,--where the n end of the magnet faces the s side of the magnetic shell; and that in a, where two norths face, the line of repulsion has the same general character as in c, in which the n end of the magnet faces the n side of the shell. [illustration: fig. .] [illustration: fig. a.] instead of placing the magnet perpendicular to the plane of the loop, it may be placed parallel to its plane. fig. d shows the magnet and loop both vertical. the field shows that the magnet will be rotated, and will finally take for stable equilibrium an axial position, with the n end pointing as determined by the rule already given. [illustration: fig. d.] if two loops are placed with their axes in the same straight line as follows, figs. f, g, a reproduction of figs. b and c will become evident. it is obvious from these spectra that the two loops attract or repel each other according to the direction of the current, which fact may be shown by bringing a loop near to another loop suspended from the ring stand, fig. , or by using the ordinary apparatus for that purpose--de la rive's battery and ampere's stand. [illustration: fig. f.] [illustration: fig. g.] if two loops are placed in the same vertical plane, as in figs. h and i, there will be attraction or repulsion, according to the direction of the adjacent currents. the fields become the same as figs. and a, as may be seen by comparing them with those figures. [illustration: fig. h.] [illustration: fig. i.] having thus demonstrated the practical identity of a loop and a magnet, we proceed to examine the effects produced by loops on straight wires. if the loop is placed with a straight wire in its plane along one edge, there will be attraction or repulsion, according to the direction of the two currents, figs. and a, which are obviously the same as figs. and a. [illustration: fig. .] [illustration: fig. a.] [illustration: fig. b.] [illustration: fig. c.] if the wire is placed parallel to the plane of the loop and to one side, figs. b and c, there will be rotation (same as figs. b and c). if the loop is horizontal and the wire vertical and on one side, the figs. d, e are the same as d and e. if the loop is horizontal and the wire vertical and axial, f and g, there will be rotation, and the figures are mere duplicates of g and h. [illustration: fig. d.] [illustration: fig. e.] [illustration: fig. f.] [illustration: fig. g.] [illustration: fig. h.] fig. h shows a view of f when the wire is horizontal and the plane of the loop vertical. it is like i. to verify these facts, suspend a loop from ampere's stand, fig. , and bring a straight wire near. a small rectangle or circle may be hung in a similar manner. when the circuit is closed, it tends to place itself with its axis in a n and s direction through the earth's influence. the supposition of an e and w horizontal earth current will explain this action. to exemplify rotation of a vertical wire by a horizontal loop, fig. may be shown. a circular copper vessel with a glass bottom (fig. ) has wound around its rim several turns of insulated wire. in the center of the vessel is a metallic upright upon the top of which is balanced in a mercury cup a light copper [inverted u] shaped strip. the ends of the inverted u dip into the dilute sulphuric acid contained in the circular vessel. the current passes from, the battery, up the pillar, down the legs of the u to the liquid, thence through the insulated wire back to the battery. [illustration: fig. .] this is the usual form of apparatus, modified in size for the vertical or horizontal lantern. (_to be continued._) * * * * * poisons. "poisons and poisoning" was the subject of a discourse a few days ago at the royal institution. the lecturer, professor meymott tidy, began by directing attention to the derivation of the word "toxicology," the science of poisons. the greek word [greek: toxon] signified primarily that specially oriental weapon which we call a bow, but the word in the earliest authors included in its meaning the arrow shot from the bow. dioscorides in the first century a.d. uses the word [greek: to toxikon] to signify the poison to smear arrows with. thus, by giving an enlarged sense to the word--for words ever strive to keep pace, if possible, with scientific progress, we get our modern and significant expression toxicology as the science of poisons and of poisoning. a certain grim historical interest gathers around the story of poisons. it is a history worth studying, for poisons have played their part in history. the "subtil serpent" taught men the power of a poisoned fang. poison was in the first instance a simple instrument of open warfare. thus, our savage ancestors tipped their arrows with the snake poison in order to render them more deadly. the use of vegetable extracts for this purpose belongs to a later period. the suggestion is not unreasonable that if war chemists with their powders, their gun cotton, and their explosives had not been invented, warlike nations would have turned for their _instrumenta belli_ to toxicologists and their poisons. at any rate, the toxicologists may claim that the very cradle of science was rocked in the laboratory of the toxicological worker. early in the history of arrow tipping the admixture of blood with the snake poison became a common practice. even the use of animal fluids alone is recorded--e.g., the arrows of hercules, which were dipped in the gall of the lernæan hydra. hercules himself at last fell a victim to the blood stained tunic of the dead centaur nessus. as late as the middle of the last century blumenbach persuaded one of his class to drink oz. of warm bullock's blood in order to disprove the then popular notion that even fresh blood was a poison. the young man who consented to drink the blood did not die a martyr to science. the first important question we have to answer is, what do we mean by a poison? the law has not defined a poison, although it requires at times a definition. the popular definition of a poison is "a drug which destroys life rapidly when taken in small quantity." the terms "small quantity" as regards amount, and "rapidly" as regards time, are as indefinite as hodge's "piece of chalk" as regards size. the professor defined a poison as "any substance which otherwise than by the agency of heat or electricity is capable of destroying life, either by chemical action on the tissues of the living body or by physiological action by absorption into the living system." this definition excepted from the list of poisons all agencies that destroyed life by a simple mechanical action, thus drawing a distinction between a "poison" and a "destructive thing." it explains why nitrogen is not a poison and why carbonic acid is, although neither can support life. this point the lecturer illustrated. a poison must be capable of destroying life. it was nonsense to talk of a "deadly poison." if a body be a poison, it is deadly; if it be not deadly, it is not a poison. three illustrations of the chemical actions of poisons were selected. the first was sulphuric acid. here the molecular death of the part to which the acid was applied was due to the tendency of sulphuric acid to combine with water. the stomach became charred. the molecular death of certain tissues destroyed the general functional rhythmicity of the system until the disturbance became general, somatic death (that is, the death of the entire body) resulting. the second illustration was poisoning by carbonic oxide. the professor gave an illustrated description of the origin and properties of the coloring matter of the blood, known as _hæmoglobin_, drawing attention to its remarkable formation by a higher synthetical act from the albumenoids in the animal body, and to the circumstance that, contrary to general rule, both its oxidation and reduction may be easily effected. it was explained that on this rhythmic action of oxidizing and reducing _hæmoglobin_ life depended. carbonic oxide, like oxygen, combined with _hæmoglobin_, produced a comparatively stable compound; at any rate, a compound so stable that it ceased to be the efficient oxygen carrier of normal _hæmoglobin_. this interference with the ordinary action of _hæmoglobin_ constituted poisoning by carbonic oxide. in connection with this subject the lecturer referred to the use of the spectroscope as an analytical agent, and showed the audience the spectrum of blood extracted from the hat of the late mr. briggs (for the murder of whom muller was executed), and this was the first case in which the spectroscopic appearances of blood formed the subject matter of evidence. the third illustration of poisoning was poisoning by strychnine. here again the power of the drug for undergoing oxidation was illustrated. it was noted that although our knowledge of the precise _modus operandi_ of the poison was imperfect, nevertheless that the coincidence of the first fit in the animal after its exhibition with the formation of reduced _hæmoglobin_ in the body was important. there followed upon this view of the chemical action of poison in the living body this question: given a knowledge of certain properties of the elements--for example, their atomic weights, their relative position according to the periodic law, their spectroscopic character, and so forth--or given a knowledge of the molecular constitution, together with the general physical and chemical properties of compounds--in other words, given such knowledge of the element or compound as may be learned in a laboratory--does such knowledge afford us any clew whereby to predicate the probable action of the element or of the compound respectively on the living body? the researches of blake, rabuteau, richet, bouchardat, fraser, and crum-brown were discussed, the results of their observations being that at present we were unable to determine toxicity or physiological action by any general chemical or physical researches. the lecturer pointed out that such relationship was scarcely to be expected. poisons acted on different tissues, while even the same poison, according to the dose administered and other conditions, expended its toxic activity in different ways. further, the allotropic modifications of elements and the isomerism of compounds increased the difficulties. why should yellow phosphorus be an active poison and red phosphorus be inert? why should piperine be the poison of all poisons to keep you awake, and morphine the poison of all poisons to send you asleep, although to the chemist these two bodies were of identical composition? the lecturer urged that the science of medicine (for the poisons of the toxicologist were the medicines of the physician) must be experimental. guard jealously against all wanton cruelty to animals; but to deprive the higher creation of life and health lest one of the lower creatures should suffer was the very refinement of cruelty. "are ye not of much more value then they?" spoke a still small voice amid the noisy babble of well intentioned enthusiasts.--_london times._ * * * * * artificial mother for infants. all the journals have recently narrated the curious story of the triplets that were born prematurely at the clinic of assas street. placed at their birth in an apparatus constructed on the principle of an incubator, in order to finish their development therein, these frail beings are doing wonderfully well, thanks to the assiduous care bestowed upon them, and are even showing, it appears, a true emulation to become persons of importance. every one now knows the incubator or "artificial hen"--that box with a glass top in which, under the influence of a mild heat, hens' eggs, laid upon wire cloth, hatch of themselves in a few days, and allow pretty little chicks to make their way out of the cracked shell. this ingenious apparatus, which has been adopted by most breeders, gives so good results that it has already supplanted the mother hens in all large poultry yards, and at present, thanks to it, large numbers of eggs that formerly ended in omelets are now changing into chickens. although not belonging to the same race, a number of children at their birth are none the less delicate than these little chicks. there are some that are so puny and frail among the many brought into the world by the anæmic and jaded women of the present generation that, in the first days of their existence, their blood, incapable of warming them, threatens at every instant to congeal in their veins. there are some which, born prematurely, are so incapable of taking nourishment of themselves, of breathing and of moving, that they would be fatally condemned to death were not haste made to take up their development where nature left it, in order to carry it on and finish it. in such a case it is not, as might be supposed, to the exceptionally devoted care of the mother that the safety of these delicate existences is confided. as the sitting hen often interferes with the hatching of her eggs by too much solicitude, so the most loving and attentive mother, in this case, would certainly prove more prejudicial than useful to her nursling. so, for this difficult task that she cannot perform, there is advantageously substituted for her what is known as an artificial mother. this apparatus, which is identical with the one employed for the incubation of chickens, consists of a large square box, supporting, upon a double bottom, a series of bowls of warm water. above these vessels, which are renewed as soon as the temperature lowers, is arranged a basket filled with cotton, and in this is laid, as in a nest, the weak creature which could not exist in the open air. [illustration: still birth warming apparatus.] through the glass in the cover, the mother has every opportunity of watching the growth of her new born babe; but this is all that she is allowed to do. the feeding of the infant, which is regulated by the physician at regular hours, is effected by means of a special rubber apparatus, through the aid of an intelligent woman who has sole charge of this essential operation. the aeration of the little being, which is no less important, is assured by a free circulation, in the box, of pure warm air, which is kept at a definite temperature and is constantly renewed through a draught flue. the least variations in the temperature are easily seen through a horizontal thermometer placed beneath the glass. thus protected against all those bad influences that are often so fatal at the inception of life, even to the healthiest babes, preserved from an excess or insufficiency of food, sheltered from cold and dampness, protected against clumsy handling and against pernicious microbes, sickly or prematurely born babies soon acquire enough strength in the apparatus to be able, finally, like others, to face the various perils that await us from the cradle. the results that have been obtained for some time back at paris, where the surroundings are so unfavorable, no longer leave any doubt as to the excellence of the process. at the lying-in clinic of assas street, doctors farnier, chantreuil, and budin succeeded in a few days in bringing some infants born at six months (genuine human dolls, weighing scarcely more than from ¼ to ½ pounds) up to the normal weight of ½ pounds.--_l'illustration._ * * * * * gastrostomy. surgery has, as is well known, made great progress in recent years. apropos of this subject, we shall describe to our readers an operation that was recently performed by one of our most skillful surgeons, dr. terrillon, under peculiar circumstances, in which success is quite rare. the subject was a man whose oesophagus was obstructed, and who could no longer swallow any food, or drink the least quantity of liquid, and to whom death was imminent. dr. terrillon made an incision in the patient's stomach, and, through a tube, enabled him to take nourishment and regain his strength. we borrow a few details concerning the operation from a note presented by the doctor at one of the last meetings of the academy of medicine. [illustration: fig. .--feeding a patient through a stomachal tube.] [illustration: fig. .--details of the tube. c, rubber tube for leading food to the stomach, e; b b', rubber balls, which, inflated with air by means of the tube, t, and rubber ball, p, effect a hermetic closing; a, stopper for the tube, c; r, cock of the air tube.] mr. x., fifty-three years of age, is a strong man of arthritic temperament. he has suffered for several years with violent gastralgia and obstinate dyspepsia, for which he has long used morphine. the oesophagal symptoms appear to date back to the month of september, , when he had a painful regurgitation of a certain quantity of meat that he had swallowed somewhat rapidly. since that epoch, the passage of solid food has been either painful or difficult, and often followed by regurgitation. the food seemed to stop at the level of the pit of the stomach. so he gave up solid food, and confined himself to liquids or semi-liquids, which readily passed up to december , . at this epoch, he remarked that liquids were swallowed with difficulty, especially at certain moments, they remaining behind the sternum and afterward slowly descending or being regurgitated. this state of things was more marked especially in the first part of january. he was successfully sounded several times, but soon the sound was not able to pass. doctors affre and bazenet got him to come to paris, where he arrived february , . for ten days, the patient had not been able to swallow anything but about a quart of milk or bouillon in small doses. as soon as he had swallowed the liquid, he experienced distress over the pit of the stomach, followed by painful regurgitations. for three days, every attempt made by dr. terrillon to remove the obstacle that evidently existed at the level of the cardia entirely failed. several times after such attempts a little blood was brought out, but there was never any hemorrhage. the patient suffered, grew lean and impatient, and was unable to introduce into his stomach anything but a few spoonfuls of water from time to time. as he was not cachectic and no apparent ganglion was found, and as his thoracic respiration was perfect, it seemed to be indicated that an incision should be made in his stomach. the patient at once consented. the operation was performed february , at o'clock, with the aid of dr. routier, the patient being under the influence of chloroform. a small aperture was made in the wall of the stomach and a red rubber sound was at once introduced in the direction of the cardia and great tuberosity. this gave exit to some yellowish gastric liquid. the tube was fixed in the abdominal wall with a silver wire. the operation took three quarters of an hour. the patient was not unduly weakened, and awoke a short time afterward. he had no nausea, but merely a burning thirst. the operation was followed by no peritoneal reaction or fever. three hours afterward, bouillon and milk were injected and easily digested. passing in silence the technical details, which would not interest the majority of our readers, we shall be content to say that mr. x., thanks to this alimentation, has regained his strength, and is daily taking his food as shown in fig. . the aperture made in the stomach permits of the introduction of the rubber apparatus shown in fig. , the object of which is to prevent the egress of the liquids of the stomach and at the same time to introduce food. a funnel is fitted to the tube, and the liquid or semi-liquid food is directly poured into the stomach. digestion proceeds with perfect regularity, and mr. x., who has presented himself, of his own accord, before the academy, and whom we have recently seen, has resumed his health and good spirits.--_la nature._ * * * * * how to catch and preserve moths and butterflies. there is no part of our country in which one cannot form a beautiful local collection, and any young person who wants amusement, instruction, and benefit from two, three, or more weeks in the country can find all in catching butterflies and moths, arranging them, and studying them up. provide yourself first with two tools, a net and a poison bottle. the net may be made of any light material. i find the thinnest swiss muslin best. get a piece of iron wire, not as heavy as telegraph wire, bend it in a circle of about ten inches diameter, with the ends projecting from the circle two or three inches; lash this net frame to the end of a light stick four or five feet long. sew the net on the wire. the net must be a bag whose depth is not quite the length of your arm--so deep that when you hold the wire in one hand you can easily reach the bottom with the bottle (to be described) in the other hand. never touch wing of moth or butterfly with your fingers. the colors are in the dusty down (as you call it), which comes off at a touch. get a glass bottle or vial, with large, open mouth, and cork which you can easily put in and take out. the bottles in which druggists usually get quinine are the most convenient. it should not be so large that you cannot easily carry it in your pocket. let the druggist put in the bottle a half ounce of cyanide of potassium; on this pour water to the depth of about three-fourths of an inch, and then sprinkle in and mix gently and evenly enough plaster of paris to form a thick cream, which will _set_ in a cake in the bottom of the vial. let it stand open an hour to set and dry, then wipe out the inside of the vial above the cake and keep it corked. this is the regular entomological poison bottle, used everywhere. an insect put in it dies quietly at once. it will last several months. these two tools, the net and the poison bottle, are your catching and killing instruments. you know where to look for butterflies. moths are vastly more numerous, and while equally beautiful, present more varieties of beauty than butterflies. they can be found by daylight in all kinds of weather, in the grass fields, in brush, in dark woods, sometimes on flowers. many spend the daytime spread out, others with close shut wings on the trunks of trees in dark woods. the night moths are more numerous and of great variety. they come around lamps, set out on verandas in the night, in great numbers. a european fashion is to spread on tree trunks a sirup made of brown sugar and rum, and visit them once in a while at night with net and lantern. catch your moth in the net, take him out of it by cornering him with the open mouth of your poison bottle, so that you secure him unrubbed. now comes the work of stretching your moths. this is easy, but must be done carefully. provide your own stretching boards. these can be made anywhere with hammer and nail and strips of wood. you want two flat strips of wood about seven-eighths or three-fourths of an inch thick and eight to fourteen inches long, nailed parallel to each other on another strip, so as to leave a narrow open space between the two parallel strips. make two or three or more of these, with the slit or space between the strips of various widths, for large and small moths and butterflies. make as many of them, with as various widths of slit, as your catches may demand. take your moth by the feet, gently in your fingers, put a long pin down through his body, set the pin down in the slit of the stretching board, so that the body of the moth will be at the top of the slit and the wings can be laid out flat on the boards on each side. have ready narrow slips of white paper. lay out one _upper_ wing flat, raising it gently and carefully by using the point of a pin to draw it with, until the lower edge of this upper wing is nearly at a right angle with the body. pin it there temporarily with one pin, carefully, while you draw up the _under_ wing to a natural position, and pin that. put a slip of paper over both wings, pinning one end above the upper and the other below the under wing, thus holding both wings flat on the stretching board. take out the pins first put in the wings and let the paper do the holding. treat the opposite wings in the same way. put as many moths or butterflies on your stretching board as it will hold, and let them remain in a dry room for two, three, or more days, according to size of moths and dampness of climate. put them in sunshine or near a stove to hasten drying. when dry, take off the slips of paper, lift the moth out by the pin through the body, and place him permanently in your collection.--_wm. c. prime, in n.y. jour. of commerce._ * * * * * the clavi harp. the beautiful instrument which we illustrate to-day is the invention of m. dietz, of brussels. his grandfather was one of the first manufacturers of upright pianos, and being struck with the difficulties and defects of the harp, constructed, in , an instrument _à cordes pincées à clavier_--the strings connected with a keyboard. many improvements have from time to time been made on this model, which at last arrived at the perfection exhibited in the newly patented clavi harp. the difficulty of learning to play the ordinary harp, and the inherent inconveniences of the instrument, limit its use. it is furnished with catgut strings, which are affected by all the influences of temperature, and require to be frequently tuned. the necessity of playing the strings with the fingers renders it difficult to obtain equality in the sounds. it gives only the natural sounds of the diatonic gamut, and in order to obtain changes of modulation, the pedals must be employed. harmonics and shakes are very difficult to execute on the harp, and--last, but not least--it is not provided with dampers. the external form of the clavi harp resembles that of the harp, and all the cords, or strings, are visible. the mechanism which produces the sound is put into motion directly a key is depressed, and acts in a similar manner to the fingers of a harpist; the strings being pulled, not struck. the clavi harp is free from all the objections inherent in the ordinary harp. the strings are of a peculiar metal, covered with an insulating material, which has for its object the production of sounds similar to that obtained from catgut strings, and to prevent the strings from falling out of tune. the keyboard, exactly like that of a piano, permits of playing in all keys, without the employment of pedals. the clavi harp has two pedals. the first, connected with the dampers, permits the playing of sustained sounds, or damping them instantaneously. the second pedal divides certain strings into two equal parts, to give the harmonic octaves; by the aid of this pedal the performer can produce ten harmonic sounds simultaneously; on the ordinary harp only four simultaneous harmonics are possible. an ordinary keyboard being the intermediary between the performer and the movement of the mechanical "fingers" which pluck the strings, perfect equality of manipulation is secured. the mechanical "fingers" instantaneously quit the strings on which they operate, and are ready for further action. the "fingers" are covered with suitable material, so that their contact with the strings takes place with the softness necessary to obtain the most beautiful tones possible. [illustration: the clavi harp.] the clavi harp is much lighter than the piano--so that it can easily be moved from room to room, or taken into an orchestra, by one or two persons--and is of an elegant form, favorable to artistic decoration. sufficient will have been said to give a general idea of the new instrument. it is undeniable that at the present day that beautiful instrument, the harp, is seldom played; still seldomer well played. this is attributable to the difficulties it presents to pupils. its seven pedals must be employed in different ways when notes are to be raised or lowered a semitone; chromatic passages easy of execution on the piano are almost impracticable on the harp. the same may be said of the shake; and it is only after long and exclusive devotion to its study that the harp can become endurable in the hands of an amateur, or the means of furnishing a professional harpist with a moderate income. it is needless to point out how far, in these respects, the harp is surpassed by the clavi harp. vocalists who accompany themselves on the harp are forced, by the extension of their arms to reach the lower strings, and by frequent employment of their feet on the pedals, into postures and movements unfavorable to voice production; but they can accompany themselves with ease on the clavi harp. composers are restricted in the introduction of harp passages in their orchestral scores, owing to the paucity of harpists. in some cases, composers have written harp passages beyond the possibility of execution by a single harpist, and the difficulty and cost of providing two harpists have been inevitable. these difficulties will disappear, and composers may give full play to their inspirations, when the harp is displaced by the clavi harp.--_building news._ * * * * * the argand burner. argand, a poor swiss, invented a lamp with a wick fitted into a hollow cylinder, up which a current of air was permitted to pass, thus giving a supply of oxygen to the interior as well as the exterior of the circular frame. at first argand used the lamp without a glass chimney. one day he was busy in his work room and sitting before the burning lamp. his little brother was amusing himself by placing a bottomless oil flask over different articles. suddenly he placed it upon the flame of the lamp, which instantly shot up the long, circular neck of the flask with increased brilliancy. it did more, for it flashed into argand's mind the idea of the lamp chimney, by which his invention was perfected. * * * * * the subterranean temples of india. during the last fifteen years bombay has undergone a complete transformation, and the english are now making of it one of the prettiest cities that it is possible to see. the environs likewise have been improved, and thanks to the railways and _bungalows_ (inns), many excursions may now be easily made, and tourists can thus visit the wonders of india, such as the subterranean temples of ajunta, elephanta, nassik, etc., without the difficulties of heretofore. the excavations of elephanta are very near bombay, and the trip in the bay by boat to the island where they are located is a delightful one. the deplorable state in which these temples now exist, with their broken columns and statues, detracts much from their interest. the temples of ajunta, perhaps the most interesting of all, are easier of access, and are situated miles from bombay and far from the railway station at pachora, where it is necessary to leave the cars. here an ox cart has to be obtained, and thirty miles have to be traveled over roads that are almost impassable. it takes the oxen fifteen hours to reach the bungalow of furdapore, the last village before the temples, and so it is necessary to purchase provisions. in these wild and most picturesque places, the hindoos cannot give you a dinner, even of the most primitive character. it was formerly thought that the subterranean temples of india were of an extraordinary antiquity. the hindoos still say that the gods constructed these works, but of the national history of the country they are entirely ignorant, and they do not, so to speak, know how to estimate the value of a century. the researches made by mr. jas. prinsep between and have enlightened the scientific world as to the antiquity of the monuments of india. he succeeded in deciphering the buddhist inscriptions that exist in all the north of india beyond the indus as far as to the banks of the bengal. these discoveries opened the way to the work done by mr. turnour on the buddhist literature of ceylon, and it was thus that was determined the date of the birth of sakya muni, the founder of buddhism. he was born b.c. and his death occurred eighty years later, in . it is also certain that buddhism did not become a true religion until years after these events, under the reign of aoska. the first subterranean temples cannot therefore be of a greater antiquity. researches that have been made more recently have in all cases confirmed these different results, and we can now no longer doubt that these temples have been excavated within a period of fourteen centuries. dasaratha, the grandson of aoska, first excavated the temples known under the name of milkmaid, in behar (bengal), b.c., and the finishing of the last monument of ellora, dedicated by indradyumna to indra subha, occurred during the twelfth century of our era. [illustration: fig. .--facade of the temple of pandu lena.] we shall speak first of the temples of pandu lena, situated in the vicinity of nassik, near bombay. these are less frequented by travelers, and that is why i desired to make a sketch of them (fig. ). the church of pandu lena is very ancient. inscriptions have been found upon its front, and in the interior on one of the pillars, that teach us that it was excavated by an inhabitant of nassik, under the reign of king krishna, in honor of king badrakaraka, the fifth of the dynasty of sunga, who mounted the throne b.c. the front of this church, all carved in the rock, is especially remarkable by the perfection of the ornaments. in these it is to be seen that the artist has endeavored to imitate in rock a structure made of wood. this is the case in nearly all the subterranean temples, and it is presumable that the architects of the time did their composing after the reminiscences of the antique wooden monuments that still existed in india at their epoch, but which for a long time have been forever destroyed. the large bay placed over the small front door gives a mysterious light in the nave of the church, and sends the rays directly upon the main altar or _dagoba_, leaving the lateral columns and porticoes in a semi-obscurity well calculated to inspire meditation and prayer. the temples and monasteries of ajunta, too, are of the highest interest. they consist of grottoes, of which four only are churches or _chaityas_. the other excavations compose the monasteries or _viharas_. begun b.c., they have remained since the tenth century of our era as we now see them. the subterranean monasteries are majestic in appearance. sustained by superb columns with curiously sculptured capitals, they are ornamented with admirable frescoes which make us live over again the ancient hindoo life. the paintings are unfortunately in a sad state, yet for the tourist they are an inexhaustible source of interesting observations. the excavations, which have been made one after another in the wall of volcanic rock of the mountain, form, like the latter, a sort of semicircle. but the churches and monasteries have fronts whose richness of ornamentation is unequaled. the profusion of the sculptures and friezes, ornamented with the most artistic taste, strikes you with so much the more admiration in that in these places they offer a perfect and varied _ensemble_ of the true type of the buddhist religion during this long period of centuries. the picturesque landscape that surrounds these astonishing sculptures adds to the beauty of these various pictures. the temples of ellora are no less remarkable, but they do not offer the same artistic _ensemble_. the excavations may be divided into three series: ten of them belong to the religion of buddha, fourteen to that of brahma, and six to the dravidian sect, which resembles that of jaius, of which we still have numerous specimens in the indies. excavated in the same amygdaloid rock, the temples and monasteries differ in aspect from those of ajunta, on account of the form of the mountain. ajunta is a nearly vertical wall. at ellora, the rock has a gentle slope, so that, in order to have the desired height for excavating the immense halls of the _viharas_ or the naves of the _chaityas_, it became necessary to carve out a sort of forecourt in front of each excavation. [illustration: fig. .--plan of the temples of kylas.] some of the churches thus have their entrance ornamented with porticoes, and the immense monasteries (which are sometimes three stories high) with lateral entrances and facades. the mountain has also been excavated in other places, so as to form a relatively narrow entrance, which gives access to the internal court of one of these monasteries. it thus becomes nearly invisible to whoever passes along the road formed on the sloping side of the mountain. the greatest curiosity among the monuments of ellora is the group of temples known by the name of kylas (fig. ). the monks have excavated the rocky slope on three faces so as to isolate completely, in the center, an immense block, out of which they have carved an admirable temple (see t in the plan, fig. ), with its annexed chapels. these temples are thus roofless and are sculptured externally in the form of pagodas. literally covered with sculptures composed with infinite art, they form a very unique collection. these temples seem to rest upon a fantastic base in which are carved in alto rilievo all the gods of hindoo mythology, along with symbolic monsters and rows of elephants. these are so many caryatides of strange and mysterious aspect, certainly designed to strike the imagination of the ancient indian population (fig. ). [illustration: fig. .--subterranean temple at ellora.] two flights of steps at s and s (fig. ) near the main entrance of kylas lead to the top of this unique base and to the floor of the temples. the interior of the central pagoda, ornamented with sixteen magnificent columns, formerly covered, like the walls, with paintings, and the central sanctuary that contains the great idol, are composed with a perfect understanding of architectural proportions. exit from this temple is effected through two doors at the sides. these open upon a platform where there are five pagodas of smaller size that equal the central temple in the beauty of their sculptures and the elegance of their proportions. around these temples great excavations have been made in the sides of the mountain. at a (fig. ), on a level with the ground, is seen a great cloister ornamented with a series of bass reliefs representing the principal gods of the hindoo paradise. the side walls contain large, two-storied halls ornamented with superb sculptures of various divinities. columns of squat proportions support the ceilings. a small stairway, x (fig. ), leads to one of these halls. communication was formerly had with its counterpart by a stone bridge which is now broken. there still exist two (p) which lead from the floor of the central temple to the first story of the detached pavilion or _mantapa_, d, and to that of the entrance pavilion or _gopura_, c. at g we still see two sorts of obelisks ornamented with arabesques and designed for holding the fires during religious fetes. at e are seen two colossal elephants carved out of the rock. these structures, made upon a general plan of remarkable character, are truly without an equal in the entire world. we may thus see how much art feeling the architects of these remote epochs possessed, and express our wonder at the extreme taste that presided over all these marvelous subterranean structures.--_a. tissandier, in la nature._ * * * * * [nature.] timber, and some of its diseases.[ ] [footnote : continued from supplement, no, , p. .] by h. marshall ward. iv. before proceeding further it will be of advantage to describe another tree-killing fungus, which has long been well known to mycologists as one of the commonest of our toadstools growing from rotten stumps and decaying wood-work such as old water pipes, bridges, etc. this is _agaricus melleus_ (fig. ), a tawny yellow toadstool with a ring round its stem, and its gills running down on the stem and bearing white spores, and which springs in tufts from the base of dead and dying trees during september and october. it is very common in this country, and i have often found it on beeches and other trees in surrey, but it has been regarded as simply springing from the dead rotten wood, etc., at the base of the tree. as a matter of fact, however, this toadstool is traced to a series of dark shining strings, looking almost like the purple-black leaf stalks of the maidenhair fern, and these strings branch and meander in the wood of the tree, and in the soil, and may attain even great lengths--several feet, for instance. the interest of all this is enhanced when we know that until the last few years these long black cords were supposed to be a peculiar form of fungus, and were known as _rhizomorpha_. they are, however, the subterranean vegetative parts (mycelium) of the agaric we are concerned with, and they can be traced without break of continuity from the base of the toadstool into the soil and tree (fig. ). i have several times followed these dark mycelial cords into the timber of old beeches and spruce fir stumps, but they are also to be found in oaks, plums, various conifers, and probably may occur in most of our timber trees if opportunity offers. the most important point in this connection is that _agaricus melleus_ becomes in these cases a true parasite, producing fatal disease in the attacked timber trees, and, as hartig has conclusively proved, spreading from one tree to another by means of the rhizomorphs under ground. only the last summer i had an opportunity of witnessing, on a large scale, the damage that can be done to timber by this fungus. hundreds of spruce firs with fine tall stems, growing on the hillsides of a valley in the bavarian alps, were shown to me as "victims to a kind of rot." in most cases the trees (which at first sight appeared only slightly unhealthy) gave a hollow sound when struck, and the foresters told me that nearly every tree was rotten at the core. i had found the mycelium of _agaricus melleus_ in the rotting stumps of previously felled trees all up and down the same valley, but it was not satisfactory to simply assume that the "rot" was the same in both cases, though the foresters assured me it was so. [illustration: fig. .--a small group of _agaricus (armillaria) melleus_. the toadstool is tawny yellow, and produces white spores; the gills are decurrent, and the stem bears a ring. the fine hair-like appendages on the pileus should be bolder.] by the kindness of the forest manager i was allowed to fell one of these trees. it was chosen at hazard, after the men had struck a large number, to show me how easily the hollow trees could be detected by the sound. the tree was felled by sawing close to the roots; the interior was hollow for several feet up the stem, and two of the main roots were hollow as far as we could poke canes, and no doubt further. the dark-colored rotting mass around the hollow was wet and spongy, and consisted of disintegrated wood held together by a mesh work of the rhizomorphs. further outward the wood was yellow, with white patches scattered in the yellow matrix, and, again, the rhizomorph strands were seen running in all directions through the mass. [illustration: fig. .--sketch of the base of a young tree (s) killed by _agaricus melleus_, which has attacked the roots, and developed rhizomorphs at r, and fructifications. to the right the fructifications have been traced by dissection to the rhizomorph strands which produced them.] not to follow this particular case further--since we are concerned with the general features of the diseases of timber--i may pass to the consideration of the diagnosis of this disease caused by _agaricus melleus_, as contrasted with that due to _trametes radiciperda_. of course no botanist would confound the fructification of the _trametes_ with that of the _agaricus_; but the fructifications of such fungi only appear at certain seasons, and that of _trametes radiciperda_ may be underground, and it is important to be able to distinguish such forms in the absence of the fructifications. the external symptoms of the disease, where young trees are concerned, are similar in both cases. in a plantation at freising, in bavaria, prof. hartig showed me young weymouth pines (_p. strobus_) attacked and killed by _agaricus melleus_. the leaves turn pale and yellow, and the lower part of the stem--the so-called "collar"--begins to die and rot, the cortex above still looking healthy. so far the symptoms might be those due to the destructive action of other forms of tree-killing fungi. on uprooting a young pine, killed or badly attacked by the agaric, the roots are found to be matted together with a ball of earth permeated by the resin which has flowed out; this is very pronounced in the case of some pines, less so in others. on lifting up the scales of the bark, there will be found, not the silky white, delicate mycelium of the _trametes_, but probably the dark cord-like rhizomorphs; there may also be flat white rhizomorphs in the young stages, but they are easily distinguished. these dark rhizomorphs may also be found spreading around into the soil from the roots, and they look so much like thin roots indeed that we can at once understand their name--rhizomorph. the presence of the rhizomorphs and (in the case of the resinous pines) the outflow of resin and sticking together of soil and roots are good distinctive features. no less evident are the differences to be found on examining the diseased timber, as exemplified by prof. hartig's magnificent specimens. the wood attacked assumes brown and bright yellow colors, and is marked by sharp brown or nearly black lines, bounding areas of one color and separating them from areas of another color. in some cases the yellow color is quite bright--canary yellow, or nearly so. the white areas scattered in this yellow matrix have no black specks in them, and can thus be distinguished from those due to the _trametes_. in advanced stages the purple-black rhizomorphs will be found in the soft, spongy wood. the great danger of _agaricus melleus_ is its power of extending itself beneath the soil by means of the spreading rhizomorphs; these are known to reach lengths of several feet, and to pass from root to root, keeping a more or less horizontal course at a depth of six or eight inches or so in the ground. on reaching the root of another tree, the tips of the branched rhizomorph penetrate the living cortex, and grow forward in the plane of the cambium, sending off smaller ramifications into the medullary rays and (in the case of the pines, etc.) into the resin passages. the hyphæ of the ultimate twigs enter the tracheides, vessels, etc., of the wood, and delignify them, with changes of color and substance as described. reference must be made to prof. hartig's publications for the details which serve to distinguish histologically between timber attacked by _agaricus melleus_ and by _trametes_ or other fungi. enough has been said to show that diagnosis is possible, and indeed to an expert not difficult. it is at least clear from the above sketch that we can distinguish these two kinds of diseases of timber, and it will be seen on reflection that this depends on knowledge of the structure and functions of the timber and cambium on the one hand and proper acquaintance with the biology of the fungi on the other. it is the victory of the fungus over the timber in the struggle for existence which brings about the disease; and one who is ignorant of these points will be apt to go astray in any reasoning which concerns the whole question. any one knowing the facts and understanding their bearings, on the contrary, possesses the key to a reasonable treatment of the timber; and this is important, because the two diseases referred to can be eradicated from young plantations and the areas of their ravages limited in older forests. suppose, for example, a plantation presents the following case. a tree is found to turn sickly and die, with the symptoms described, and trees immediately surrounding it are turning yellow. the first tree is at once cut down, and its roots and timber examined, and the diagnosis shows the presence of _agaricus melleus_ or of _trametes radiciperda_, as the case may be. knowing this, the expert also knows more. if the timber is being destroyed by the _trametes_, he knows that the ravaging agent can travel from tree to tree by means of roots in contact, and he at once cuts a ditch around the diseased area, taking care to include the recently infected and neighboring trees. then the diseased timber is cut, because it will get worse the longer it stands, and the diseased parts burnt. if _agaricus melleus_ is the destroying agent, a similar procedure is necessary; but regard must be had to the much more extensive wanderings of the rhizomorphs in the soil, and it may be imperative to cut the moat round more of the neighboring trees. nevertheless, it has also to be remembered that the rhizomorphs run not far below the surface. however, my purpose here is not to treat this subject in detail, but to indicate the lines along which practical application of the truths of botanical science may be looked for. the reader who wishes to go further into the subject may consult special works. of course the spores are a source of danger, but need be by no means so much so where knowledge is intelligently applied in removing young fructifications. i will now pass on to a few remarks on a class of disease-producing timber fungi which present certain peculiarities in their biology. the two fungi which have been described are true parasites, attacking the roots of living trees, and causing disease in the timber by traveling up the cambium, etc., into the stem; the fungi i am about to refer to are termed wound parasites, because they attack the timber of trees at the surfaces of wounds, such as cut branches, torn bark, frost cracks, etc., and spread from thence into the sound timber. when we are reminded how many sources of danger are here open in the shape of wounds, there is no room for wonder that such fungi as these are so widely spread. squirrels, rats, cattle, etc., nibble or rub off bark; snow and dew break branches; insects bore into stems; wind, hail, etc., injure young parts of trees, and in fact small wounds are formed in such quantities that if the fructifications of such fungi as those referred to are permitted to ripen indiscriminately, the wonder is not that access to the timber is gained, but rather that a tree of any considerable age escapes at all. one of the commonest of these is _polyporus sulphureus_, which does great injury to all kinds of standing timber, especially the oak, poplar, willow, hazel, pear, larch, and others. it is probably well known to all foresters, as its fructification projects horizontally from the diseased trunks as tiers of bracket-shaped bodies of a cheese-like consistency; bright yellow below, where the numerous minute pores are, and orange or somewhat vermilion above, giving the substance a coral-like appearance. i have often seen it in the neighborhood of englefield green and windsor, and it is very common in england generally. if the spore of this _polyporus_ lodges on a wound which exposes the cambium and young wood, the filaments grow into the medullary rays and the vessels and soon spread in all directions in the timber, especially longitudinally, causing the latter to assume a warm brown color and to undergo decay. in the infested timber are to observed radial and other crevices filled with the dense felt-like mycelium formed by the common growth of the innumerable branched filaments. in bad cases it is possible to strip sheets of this yellowish white felt work out of the cracks, and on looking at the timber more closely (of the oak, for instance), the vessels are found to be filled with the fungus filaments, and look like long white streaks in longitudinal sections of the wood--showing as white dots in transverse sections. it is not necessary to dwell on the details of the histology of the diseased timber; the ultimate filaments of the fungus penetrate the walls of all the cells and vessels, dissolve and destroy the starch in the medullary rays, and convert the lignified walls of the wood elements back again into cellulose. this evidently occurs by some solvent action, and is due to a ferment excreted from the fungus filaments, and the destroyed timber becomes reduced to a brown mass of powder. i cannot leave this subject without referring to a remarkably interesting museum specimen which prof. hartig showed and explained to me last summer. this is a block of wood containing an enormous irregularly spheroidal mass of the white felted mycelium of this fungus, _polyporus sulphureus_. the mass had been cut clean across, and the section exposed a number of thin brown ovoid bodies embedded in the closely woven felt; these bodies were of the size and shape of acorns, but were simply hollow shells filled with the same felt-like mycelium as that in which they were embedded. they were cut in all directions, and so appeared as circles in some cases. these bodies are, in fact, the outer shells of so many acorns, embedded in and hollowed out by the mycelium of _polyporus sulphureus_. hartig's ingenious explanation of their presence speaks for itself. a squirrel had stored up the acorns in a hollow in the timber, and had not returned to them--what tragedy intervenes must be left to the imagination. the _polyporus_ had then invaded the hollow, and the acorns, and had dissolved and destroyed the cellular and starchy contents of the latter, leaving only the cuticularized and corky shells, looking exactly like fossil eggs in the matrix. i hardly think geology can beat this for a true story. the three diseases so far described serve very well as types of a number of others known to be due to the invasion of timber and the dissolution of the walls of its cells, fibers, and vessels by hymenomycetous fungi, i.e., by fungi allied to the toadstools and polypores. they all "rot" the timber by destroying its structure and substance, starting from the cambium and medullary rays. to mention one or two additional forms, _trametes pini_ is common on pines, but, unlike its truly parasitic ally, _tr. radiciperda_, which attacks sound roots, it is a wound parasite, and seems able to gain access to the timber only if the spores germinate on exposed surfaces. the disease it produces is very like that caused by its ally; probably none but an expert could distinguish between them, though the differences are clear when the histology is understood. _polyporus fulvus_ is remarkable because its hyphæ destroy the middle lamella, and thus isolate the tracheides in the timber of firs; _polyporus borealis_ also produces disease in the timber of standing conifers; _polyporus igniarius_ is one of the commonest parasites on trees such as the oak, etc., and produces in them a disease not unlike that due to the last form mentioned; _polyporus dryadeus_ also destroys oaks, and is again remarkable because its hyphæ destroy the middle lamella. with reference to the two fungi last mentioned i cannot avoid describing a specimen in the museum of forest botany in munich, since it seems to have a possible bearing on a very important question of biology, viz., the action of soluble ferments. it has already been stated that some of these tree-killing fungi excrete ferments which attack and dissolve starch grains, and it is well known that starch grains are stored up in the cells of the medullary rays found in timber. now, _polyporus dryadeus_ and _p. igniarius_ are such fungi; their hyphæ excrete a ferment which completely destroys the starch grains in the cells of the medullary rays of the oak, a tree very apt to be attacked by these two parasites, though _p. igniarius_, at any rate, attacks many other dicotyledonous trees as well. it occasionally happens that an oak is attacked by both of these polyporei, and their mycelia become intermingled in the timber; when this is the case, the _starch grains remain intact in those cells which are invaded simultaneously by the hyphæ of both fungi_. prof. hartig lately showed me longitudinal radial sections of oak timber thus attacked, and the medullary rays showed up as glistening white plates. these plates consist of nearly pure starch; the hyphæ have destroyed the cell walls, but left the starch intact. it is easy to suggest that the two ferments acting together exert (with respect to the starch) a sort of inhibitory action one on the other; but it is also obvious that this is not the ultimate explanation, and one feels that the matter deserves investigation. it now becomes a question--what other types of timber diseases shall be described? of course the limits of a popular article are too narrow for anything approaching an exhaustive treatment of such a subject, and nothing has as yet been said of several other diseases due to crust-like fungi often found on decaying stems, or of others due to certain minute fungi which attack healthy roots. then there is a class of diseases which commence in the bark or cortex of trees, and extend thence into the cambium and timber: some of these "cankers," as they are often called, are proved to be due to the ravages of fungi, though there is another series of apparently similar "cankers" which are caused by variations in the environment--the atmosphere and weather generally. it would need a long article to place the reader _au courant_ with the chief results of what is known of these diseases, and i must be content here with the bare statement that these "cankers" are in the main due to local injury or destruction of the cambium. if the normal cylindrical sheet of cambium is locally irritated or destroyed, no one can wonder that the thickening layers of wood are not continued normally at the locality in question; the uninjured cells are also influenced, and abnormal cushions of tissue formed, which vary in different cases. now, in "cankers" this is--put shortly--what happens: it may be, and often is, due to the local action of a parasitic fungus; or it may be, and, again, often is, owing to injuries produced by the weather, in the broad sense, and saprophytic organisms may subsequently invade the wounds. the details as to how the injury thus set up is propagated to other parts--how the "canker" spreads into the bark and wood around--_are_ details, and would require considerable space for their description: the chief point here is again the destructive action of mycelia of various fungi, which by means of their powers of pervading the cells and vessels of the wood, and of secreting soluble ferments which break down the structure of the timber, render the latter diseased and unfit for use. the only too well known larch disease is a case in point; but since this is a subject which needs a chapter to itself, i may pass on to more general remarks on what we have learned so far. it will be noticed that, whereas such fungi as _trametes radiciperda_ and _agaricus melleus_ are true parasites which can attack the living roots of trees, the other fungi referred to can only reach the interior of the timber from the exposed surfaces of wounds. it has been pointed out along what lines the special treatment of the former diseases must be followed, and it only remains to say of the latter: take care of the cortex and cambium of the tree, and the timber will take care of itself. it is unquestionably true that the diseases due to wound parasites can be avoided if no open wounds are allowed to exist. many a fine oak and beech perishes before its time, or its timber becomes diseased and a high wind blows the tree down, because the spores of one of these fungi alight on the cut or torn surface of a pruned or broken branch. of course it is not always possible to carry out the surgical operations, so to speak, which are necessary to protect a tree which has lost a limb, and in other cases no doubt those responsible have to discuss whether it costs more to perform the operations on a large scale than to risk the timber. with these matters i have nothing to do here, but the fact remains that by properly closing over open wounds, and allowing the surrounding cambium to cover them up, as it will naturally do, the term of life of many a valuable tree can be prolonged, and its timber not only prevented from becoming diseased and deteriorating, but actually increased in value. there is no need probably for me to repeat that, although the present essay deals with certain diseases of timber due to fungi, there are other diseases brought about entirely by inorganic agencies. some of these were touched upon in the last article, and i have already put before the readers of _nature_ some remarks as to how trees and their timber may suffer from the roots being in an unsuitable medium. in the next paper it is proposed to deal with the so-called "dry rot" in timber which has been felled and cut up--a disease which has produced much distress at various times and in various countries. * * * * * the scientific american architects and builders edition $ . a year. single copies, cts. this is a special edition of the scientific american, issued monthly--on the first day of the month. each number contains about forty large quarto pages, equal to about two hundred ordinary book pages, forming, practically, a large and splendid magazine of architecture, richly adorned with _elegant plates in colors_ and with, fine engravings, illustrating the most interesting examples of modern architectural construction and allied subjects. a special feature is the presentation in each number of a variety of the latest and best plans for private residences, city and country, including those of very moderate cost as well as the more expensive. drawings in perspective and in color are given, together with full plans, specifications, costs, bills of estimate, and sheets of details. no other building paper contains so many plans, details, and specifications regularly presented as the scientific american. hundreds of dwellings have already been erected on the various plans we have issued during the past year, and many others are in process of construction. architects, builders, and owners will find this work valuable in furnishing fresh and useful suggestions. all who contemplate building or improving homes, or erecting structures of any kind, have before them in this work an almost _endless series of the latest and best examples_ from which to make selections, thus saving time and money. many other subjects, including sewerage, piping, lighting, warming, ventilating, decorating, laying out of grounds, etc., are illustrated. an extensive compendium of manufacturers' announcements is also given, in which the most reliable and approved building materials, goods, machines, tools, and appliances are described and illustrated, with addresses of the makers, etc. the fullness, richness, cheapness, and convenience of this work have won for it the largest circulation of any architectural publication in the world. munn & co., publishers, broadway, new york. * * * * * a catalogue of valuable books on architecture, building, carpentry, masonry, heating, warming, lighting, ventilation, and all branches of industry pertaining to the art of building, is supplied free of charge, sent to any address. * * * * * building plans and specifications. in connection with the publication of the building edition of the scientific american, messrs. munn & co. furnish plans and specifications for buildings of every kind, including churches, schools, stores, dwellings, carriage houses, barns, etc. in this work they are assisted by able and experienced architects. full plans, details, and specifications for the various buildings illustrated in this paper can be supplied. those who contemplate building, or who wish to alter, improve, extend, or add to existing buildings, whether wings, porches, bay windows, or attic rooms, are invited to communicate with the undersigned. our work extends to all parts of the country. estimates, plans, and drawings promptly prepared. terms moderate. address munn & co., broadway, new york. * * * * * the scientific american supplement. published weekly terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . stitched in paper, or $ . bound in stiff covers. combined rates.--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway, new york, n.y. * * * * * patents. in connection with the scientific american, messrs. munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american, of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats, trade marks, their costs, and how procured. address munn & co., broadway, new york. branch office, and f st., washington, d.c. proofreading canada team at http://www.pgdpcanada.net images generously provided by "making of america" cornell university. the new york scientific american: _published weekly at fulton street, (sun building,) new york._ by munn & company. * * * * * rufus porter, editor. * * * * * terms.--$ a year--$ in advance, and the remainder in months. [illustration: hand pointing right] _see advertisement on last page._ =the new roman road.= [the present pope has given his consent to build railroads in his dominions, which the former pope was averse to. the following lines are predicated on his consent.] ancient romans, ancient romans-- cato, scipio africanus, ye whose fame's eclips'd by no man's, publius Æmilianus, sylla, marius, pompey, cæsar, fabius, dilatory teaser, coriolanus, and ye gracchi who gave so many a foe a black eye, antony, lepidus, and crassus; and you, ye votaries of parnassus, virgil, and horace, and tibullus, terence and juvenal, catullus, martial, and all ye wits beside, on pegasus expert to ride; numa, good king, surnamed pampilius, and tullus, eke 'yclept hostilius-- kings, consuls, imperators, lictors, prætors, the whole world's former victors, who sleep by yellow tiber's brink; ye mighty names--what d'ye think? the pope has sanctioned railway bills! and so the lofty aventine, and your six other famous hills will soon look down upon a 'line.' oh! if so be that hills could turn their noses up, with gesture antic, thus would the seven deride and spurn a roman work so unromantic: 'was this the ancient roman way. with tickets taken, fares to pay, stockers and engineers, perhaps-- nothing more likely--english chaps brawling away, 'go on!' for ito, and 'cut along!' instead of cito; the engine letting off its steam, with puff and whistle, snort and scream; a smell meanwhile, like burning clothes, flouting the angry roman nose? is it not conscript fathers shocking? does it not seem your mem'ry mocking? the roman and the railway station-- what an incongruous combination! how odd, with no one to adore him, terminus--and in the forum!'--[punch. =good advice.= somebody lays down the following rules to young men in business. they will apply equally well to young and old. 'let the business of every one alone, and attend to your own.--don't buy what you don't want. use every hour to advantage, and study even to make leisure hours useful. think twice before you spend a shilling; remember you have another to make for it. find recreation in looking after your business, and so your business will not be neglected in looking after recreation.--buy fair, sell fair, take care of the profits; look over the books regularly, and if you find an error, trace it out. should a stroke of misfortune come upon you in trade, retrench--work harder, but never fly the track; confront difficulties with unflinching perseverance, and they will disappear at last, and you will be honored; but shrink from the task, and you will be despised.' * * * * * in russia, coffins are generally brown, but children have pink, grown up unmarried girls sky blue, while other females are indulged with a violet color. [illustration: barnum's safety apparatus] introduction.--much has been said of late in and about new york on the subject of the adoption by steamboat proprietors of some apparatus that will in some measure secure the passengers against such casualties as have occurred on board the excelsior and several other boats. there have been a great variety of inventions introduced for the purpose of preventing explosions; but from the best information we can obtain on the subject, we are of the opinion that mr. barnum's apparatus takes a general preference over all others. it consists of an arrangement of machinery, partly within the boiler, and which is constructed on such a self-regulating principle as to keep up a supply of water within the boiler, without any attention from the engineer; and in case that the apparatus itself should become impaired or cease to operate regular, the engineer becomes instantly notified thereof. explanation.--it is inexpedient for us to give a full and minute description of the several points and peculiarities of the mechanism of this apparatus; but we may so far explain as to say that a horizontal lever inside of the boiler, being mounted on a pivot near its centre, and connected to a buoy or float at one end, as represented in the engraving, (a part of the surface of the boiler being omitted for that purpose, and not, as some might infer, to represent the apparatus attached to a boiler already burst by an explosion.) one of these floats is placed within a small enclosed box within the boiler, that it may be secure from the effect of foam which sometimes pervades the surface of the water in a steam boiler.--this lever, near its bearing, is connected to a short valve-rod, which governs the valves in a small valve-chamber, whereby the steam is occasionally admitted to operate a small steam engine, placed directly over the boiler; and this engine puts in motion a pump, by which the water in the boiler is replenished. this engine, it will be understood, is never put in operation except when the water in the boiler becomes too low: and when the water rises, the elevation of the encased float closes the valve and stops the engine. the ball on the end of the lever acts as a counterpoise to the float, (which is of stone) that it may be freely influenced by the rising or falling of the surface of the water. the small engine constructed by mr. barnum for this purpose, is well adapted to its place, and has several peculiarities whereby the valves, and consequent reciprocal motion of the engine are regulated without the use of a crank or fly-wheel: but of these we cannot at present give a minute description. the whole of this apparatus evinces much scientific ability of the inventor, daniel barnum, esq., resident at present in this city, and who has received many certificates from the first scientific men in the union, in commendation of his invention. =a piggish parvenue.= a proud porker, fancying that it was degrading to his dignity to root in the gutter, came upon the sidewalk, and full of his consequence, promenaded from morning till night, leaving his humbler companions to munch corn, husks and potatoe parings. he fared as people usually do, who from vanity assume a station they are not qualified to fill. in the gutter he would have lived in unnoticed enjoyment. on the walk he got kicked by every passenger and bitten by every cur, till hungry and bruised he was glad to return to his proper station.--[ex, paper. =wanting workmen back again.= the proprietors of the cotton mill in schuylerville, n. y., who reduced the wages of their hands, a week or two since, says the schuylerville herald, twenty-five per cent., are now, and have been for several days, endeavoring to induce them to return to their work, at the old wages; but they are too late, as most of them are engaged to work in other mills. =hard climbing.= a man in orange county was found one night climbing an over-shot wheel in a fulling mill. he was asked what he was doing. he said he was 'trying to go up to bed, but some how or other these stairs won't hold still.' there are many unlucky wights who are laboriously endeavoring to climb fortune's ladder on the same principle. =power of imagination.= an amusing incident recently occurred at williams college, which is thus related by a correspondent of the springfield gazette: the professor of chemistry, while administering, in the course of his lectures, the protoxide of nitrogen, or, as it is commonly called, laughing gas, in order to ascertain how great an influence the imagination had in producing the effects consequent on respiring it, secretly filled the india rubber gas-bag with common air instead of gas. it was taken without suspicion, and the effects, if anything, were more powerful than upon those who had really breathed the pure gas. one complained that it produced nausea and dizziness, another immediately manifested pugilistic propensities, and before he could be restrained, tore in pieces the coat of one of the bystanders, while the third exclaimed, 'this is life. i never enjoyed it before.' the laughter that followed the exposure of this gaseous trick may be imagined. =true policy.= under all circumstances there is but one honest course; and that is, to do right and trust the consequences to divine providence. 'duties are ours: events are god's.' policy, with all her cunning, can devise no rule so safe, salutary and effective, as this simple maxim. * * * * * six thousand pounds of saxony wool have been purchased in pennsylvania, at sixty-two and a half cents per pound. a list of patents _issued from the th of july to the th of july, , inclusive._ to m. w. obenchain, of springfield, ohio, for improvement in carding machines. patented th july, . to russell wildman, of hartford, ct., for improvement in machinery for forming hat bodies. patented th july, . to william sherwood, of ridgefield, ct., for improvement in carpet looms. patented th july, . to richard garsed, of frankford, pa., for improvement in operating treadle cams in looms for tweeling. patented th july, . to james ives, of hamden, ct., for improvement in locks for carriage doors. patented th july, . to jacob peebles, of concordia, la., for improvement in brick cisterns. patented th july, . to jacob shermer, of new valley, md., for improvement in winnowing machines. patented, th july, . to george levan, of gap, pa., for improvement in doubling and twisting and reeling. patented th july, . to joseph stevens, of northumberland, n. y., for improvement in fences. patented th july, . to james boss, of philadelphia, pa., for improvement in ever pointed pencils. patented th july, . to richard c. holmes and jonathan j. springer, of cape may c. h., n. j., for improvement in machinery for steering vessels. patented th july, . to daniel hoats, of mifflingburgh, pa., for improvement in threshing machines. patented th july, . to tappan townsend, of albany, n. y., for improvement in warming railroad cars.--patented th july, . to elizur l. booth, of canandaigua, n. y., for improvement in threshing machines. patented th july, . to allen eldred, of oppenheim, n. y., for improvement in potatoe ploughs. patented th july, . to amos l. reed, of pittsburgh, pa., for improvement in feeding nail plates. patented th july, . to joseph greenleaf, of north yarmouth, me., for improvement in washing machines. patented th july, . to james atwater, of new haven, ct., for improvement in door locks. patented th july, . to richard flint, of meriden, ct., for improvement in rat-tail files. patented th july, . to addison smith, of perrysburgh, ohio, for improvement in magnetic fire alarms.--patented th july, . to charles f. johnson, of oswego, n. y., for improvement in turret clocks. patented th july, . to h, d. reynolds, of mill-hall, pa., for improvement in smut machines. patented th july, . to charles edward jacot, of new york city, for improvement in lever escapements. patented th july, . to ross winans, of baltimore, md., for improvement in locomotive carriages. patented th july, . to jonathan knowles, of lowell, mass., for improvement in children's chairs and wagons. patented th july, . to moses miller, of fort ann, n. y., for improvement in sleighs. patented th july, . to william hatch, of medford, mass., for improvement in spike and nail machines.--patented th july, . [illustration: variety] =old bachelors.= they are wanderers and ramblers--never at home, making sure of a welcome wherever they roam. and ev'ry one knows that the bachelor's den is a room set apart for these singular men-- a nook in the clouds, of some five feet by four, though sometimes, perchance, it may be rather more, with skylight, or no light, ghosts, goblins and gloom, and ev'ry where termed, 'the bachelor's room.' these creatures, they say, are not valued at all, except when the herd give a bachelor's ball. then drest in their best, in their gold broidered vest, it is known as a fact, that they act with much tact, and they lisp out 'how do?' and they coo and they woo, and they smile, for a while, their fair guests to beguile; condescending and bending, for fear of offending, though inert, and they spy, they exert, with their eye, to be pert, and they sigh and to flirt, as they fly. and they whisk, and they whiz, and are brisk, when they quiz. for they meet, advancing, to be sweet, and glancing, and are fleet, and dancing, on their feet, and prancing. sliding and gliding with minuet pace, piroueting and setting with infinite grace. and jumping, and racing, and bumping, and chasing, and stumping, and pacing, and thumping, and lacing. they are flittering and glittering, gallant and gay, yawning all the morning, and lounging all day, but when he grows old, and his sunshine is past, three score years being told, brings repentance at last. he then becomes an odd old man: his warmest friend's the frying pan; he's fidgety, fretful and weary; in fine, loves nothing but self, and his dinner and wine. he rates and he prates, and reads the debates: despised by the men, and the women he hates. then prosing, and pouring, and dozing, and snoring, and cozing, and boring, and nosing, and roaring, whene'er befalls in with a rabble, his delight is to vapor and gabble. he's gruffy, and musty, and puffy, and tusty, and stuffy, and rusty, and huffy, and crusty, he sits in his slippers, with back to the door, near freezing, and grumbling, and wheezing, and mumbling, and teazing, and stumbling, and sneezing, and tumbling, and curses the carpet, or nails in the floor. oft falling, oft waking, and bawling, and aching, and sprawling, and quaking, and crawling, and shaking, his hand is unsteady: his stomach is sore, he's railing, uncheery, and failing, and dreary, and ailing, and teary, bewailing, and weary, groaning and moaning, his selfishness owning. grieving and heaving, though nought is he leaving. but pelf and ill health, himself and his wealth. he sends for a doctor, to cure or to kill, who gives him advice, and offence, and a pill, and drops him a hint about making his will, as fretful antiquity cannot be mended, the mis'rable life of a bachelor's ended. nobody misses him, nobody sighs, nobody grieves when the bachelor dies. =wellman's illustrated botany.= we have received the october number of this incomparable work, and find it equal in all respects to its "illustrious predecessors." among the flowers presented in full colors, by way of illustration, we notice the scarlet pimpernel, china aster, blue hepatia, cerus speciosus, agrimonia eupatoria, besides several other sketches of buds, sections, &c. we esteem this work worth at least double the publishers' price,--$ per annum. published at nassau street. =literary emporium.= we have hitherto neglected to notice the september and october numbers of this serious, rational and elegant periodical. each number is embellished with beautiful portraits, landscapes and flowers, and contains the most useful and interesting reading matter, as well as choice poetry and occasional music. terms $ per annum. by j. k. wellman, nassau street. =a delicate compliment.= washington was sometimes given to pleasantry. journeying east on one occasion, attended by two of his aids, he asked some young ladies at a hotel where he breakfasted, how they liked the appearance of his young men! one of them promptly replied, 'we cannot judge of the stars in the presence of the sun!' =fatal deer fight.= the skeleton heads of two deers, their antlers so closely interlocked that they cannot be disengaged without violence, were found about a month ago by a gentleman while hunting in nassau county, east florida. the ground for a quarter of an acre was completely cut up by their hoofs. =a provoking blunder.= the letter bags for the steamer cambria, despatched from this city, and containing upwards of ten thousand letters for europe, was taken from the boston post office by a country stage driver, through mistake, and the cambria was compelled to sail without them. they were returned to this city. =curious needlework.= a complete map of the state of pennsylvania, wrought in lace--in which the town, counties, rivers, &c., are all distinctly shown, each county being worked in a style of lace different from those adjoining--is being exhibited in baltimore, and commands much admiration. =the credit system.= we infer, from certain polite hints and intimation, in the 'massachusetts farmers' and mechanics' leger,' that that paper is circulated on trust. if so, the publishers are in no danger of wanting business for some years to come. =charcoal road.= the citizens of yazoo, miss., have determined to make a charcoal road over the valley swamp of that place. sixty hands cutting timber will burn and spread the coal over two miles in thirty days--the embankments being already thrown up. =quick work.= the baltimore sun says--'a communication was made from _buffalo to baltimore_ last week, and an answer was received at the telegraph office in the former city in about _two hours_!' =oregon currency.= by an act of the oregon legislature, wheat is made a lawful tender, in payment of debts or taxes, at the market prices, when delivered at such places as it is customary for the merchants to receive it. =suffering by success.= it is reported that a gentleman congratulated mr. polk on having carried all his measures through congress. mr. polk replied, 'yes, i have carried all of them through, and am the weaker for the passage of each one of them.' =a rich ore.= the detroit advertiser, in an article upon the nature of the ores in the lake superior region, remarks that messrs. robbins and hubbard, of that city, have recently assayed a specimen of native copper from lake superior, and found in ounces of copper, not only - / ounces of pure silver, but several grains of gold! =musical.= the gross receipts of a late musical festival at birmingham, amounted to $ , . the excitement was caused by performing mendleson's messiah, which we learn is to be brought out in this city. =singular accident.= the steamboat highland having got aground near turkey island, on the mississippi, a large tree, three feet in diameter, fell directly across the boat, smashing the cabin, breaking the connecting pipe, and seriously injuring the pilot. =combined accomplishments.= mr. s. lover, who recently arrived in this city, is said to be a good poet, a good painter, a good musician, full of wit, anecdotes and pleasantry--it is impossible to pass a dull evening in his company. =marriage of rossini.= this celebrated composer was married at bologna, on the th of august, after a courtship of years, to mademoiselle olympe bearrien of paris. it may change the turn of his muse. =great luck.= a poor englishman, with a wife and family living in st. louis, has had a fortune of $ , in money, and a family estate worth $ , , recently left him by a deceased relative. =zinc mines.= there are several mines of zinc in new jersey, one of which is said to consist of a deposit feet in length, and is thought to contain ore worth $ , , . =a monstrous woman.= the ohio state journal says that there is a woman in pickaway county, in that state, who weighs pounds! =old boy.= a southern paper advertises a runaway boy, _thirty-six years of age_! * * * * * by a recent telegraphic arrangement, the papers in albany, troy, utica, syracuse, auburn, rochester and buffalo, are furnished with reports from new york twice a day,--at and p. m. * * * * * the connecticut river is reported to be lower than it has been known within the remembrance of the oldest inhabitants. it is reduced to a mere brook. * * * * * a company formed in boston has commenced operation on a copper mine in cumberland, r. i. about lbs. of ore were taken out a few days since, and yields about per cent. * * * * * the hon. louis mclane gets a salary of $ a year--nearly $ per week--for holding the office of president of the baltimore and ohio railway company. * * * * * an imperial _quarter_ of indian corn, in pounds, which is equal to eight bushels of sixty pounds each. we suppose some of our readers would like to know about that. * * * * * a solution of copper is an excellent wash for purifying sinks, and removing all unpleasant effluvia. two or three applications will be effectual. * * * * * we are informed that the steamer buffalo is making arrangements for the adoption of barnum's safety apparatus. * * * * * two iron steamboats, of tons each, are to run between philadelphia and reading, pa., carrying freight and passengers. * * * * * the editor of the cincinnati commercial says that he has a project for connecting the old and new worlds by telegraph. * * * * * twelve hundred and thirty-four miles of magnetic telegraph are reported to be in actual operation in the united states. * * * * * an association of capitalists at worcester county, mass., are exploring a vein of copper in greenfield. =the true ornament.= 'the ornament of a meek and quiet spirit.' by miss e. j. andrews. i ask not for the glittering wreath, of india's sparkling diamonds rare, to deck my brow, while oft beneath, there throbs a heart with heaviest care. i ask not for the gilded chain, of perishing and worthless gold, to clasp my neck, while oft in vain the heart's best sympathies unfold. oh! give me not the worthless dust, for which vain, anxious mortals toil, to treasure up where moth and rust, doth soon corrupt the hoarded pile. i covet not the gay attire, in which vain beauty oft appears, oft that which wondering crowds admire, needeth far more their heartfelt tears. but there's an ornament i crave;-- to grant, vain world, it is not thine, it floateth not o'er yon proud wave, nor yields it me earth's richest mine. oh, may it be a guileless heart! in heaven's own sight of priceless worth! where nought corrupting e'er hath part, pure, as the source which gave it birth. _a spirit meek and pure within;_ may this, alone, my life adorn, unsullied by the touch of sin, though subject to the proud world's scorn. this ornament, o god of love! 'tis thine, and thine alone, to give; oh, may i its rich beauties prove, and in its full possession, _live_! _bethel, conn._, . =female piety.= the gem of all others which enriches the coronet of woman's character, is unaffected piety. nature may lavish much on her person; the enchantment of her countenance, the grace of her mind, the strength of her intellect; yet her loveliness is uncrowned till piety throws around the whole the sweetness and power of its charms. she then becomes unearthly in her desires and associations. the spell which bound her affections to the things below is broken, and she mounts on the silent wings of her fancy and hope to the habitation of god, where it is her delight to hold communion with the spirits that have been ransomed from the thraldom of earth and wreathed with a garland of glory. her beauty may throw a magical charm over many; princes and conquerors may bow with admiration at the shrine of her beauty and love; the sons of science may embalm her memory in the page of history; yet her piety must be her ornament, her pearl. her name must be written in 'the book of life,' that when the mountains fade away, and every memento of earthly greatness is lost in the general wreck of nature, it may remain and swell the list of that mighty throng who have been clothed in the mantle of righteousness, and their voices attuned to the melody of heaven. with such a treasure, every lofty gratification on earth may be purchased; friendship will be doubly sweet; and sorrow will lose their sting; and the character will possess a price far above rubies: life will be but a pleasant visit to earth, and entrance upon a joyful and perpetual home. and when the notes of the last trump shall be heard, and sleeping millions awake to judgment, its possessor shall be presented faultless before the throne of god with exceeding joy, and a crown of glory that shall never wear away. such is piety. like a tender flower, planted in the fertile soil of woman's heart, it grows, expanding in its foliage, and imparting its fragrance to all around, till transplanted, and set to bloom in perpetual vigor and unfading beauty, in the paradise of god. =iron ore.= one of the most valuable beds of iron ore ever discovered has been found in the northeast corner of dodge county, wisconsin, and is said to yield ninety per cent. the deposit is feet thick. * * * * * 'pursue your calling with diligence, and your creditor shall not interrupt you.' new inventions. =lewis's reversible faucet filters.= highly favorable as our opinion may be of the several excellent filters which have been introduced, we cannot avoid giving a preference to the one recently invented by mr. s. h. lewis. it consists of a very neat faucet, calculated to be attached to a common croton or other hydrant, and in connection with the faucet key, is a circular chamber, three inches in diameter, within which is a circular filter consisting of a quantity of cotton cloth, flannel sponge or porous porcelain (which is preferred) compressed between two perforated metallic disks: and the faucet key is so constructed that by turning it to the right, the water is permitted to flow through the filter in one direction; but its course is reversed and it is made to flow in the opposite direction through the filter by turning the key to the left. the filter is thus cleansed at pleasure without any trouble, on examination of the filter or chamber. they may be seen at - broadway. =west's cheap and convenient filter.= for the thousands of families in this city whose houses are not furnished with the croton water-pipes, a neat portable filter, recently invented by mr. n. west, of this city, is as near perfection, in convenience and utility, as could be furnished for the low price of _one dollar_, and should find a place in every house or shop where the croton water is used. it consists of two conical pails, one within the other; the first is furnished with an efficient filter at the bottom thereof; and the other has a faucet, by which the water is drawn off as occasion requires. they may be found at delancy street. =improved yoke for oxen.= this yoke is constructed with sliding blocks attached to the under side of the beam of the yoke, near each end, and each sliding block is attached to the beam by bolts which pass through mortises so that the blocks may be made to slide occasionally to the right or left. to these blocks are attached the bows, the position of which are adjusted by gauge screws; and by the sliding of the blocks, the distance of the oxen from each other may be regulated. the middle of the yoke is furnished with a draught staple or eye-bolt which is moveable and regulated by a hand screw at the top, whereby the _pitch_ of the draught it regulated. invented by david chappel, and entered at the patent office, sept. d. =another improvement in stoves.= messrs. hartshorn, payson & ring entered at the patent office, september d, an improved stove, in which they claim the combination of the common wood stove and cylinder coal stove, so that the coal may be burned alone, and the draught so arranged as at the same time to heat the wood stove with the same heat, and if wood alone should be burned, then the draught should be so managed and arranged as at the same time to heat the side radiators and coal cylinders. a minute description of this improvement, is not, in this place, essential. =iron shingles.= we have never been able to understand the reason why iron has so long been neglected as a covering for roofs, but are gratified to learn that mr. wm. beach, of troy, n. y., has invented and patented a mode of using cast iron plates for covering roofs. they are about one foot square, and are made to fit one into another, so as to render the roof water tight, by applying white lead to the joints. it can be afforded at cents the square foot, and probably may be so far improved as to cost no more than slate, and will be much more permanent and safe. we see no difficulty in dispensing with white lead, however, and making the seams tight without it. =improvement in the railroad track.= this improvement was entered sept. th, by john f. rogers. what he claims is the combination of the balance beam with the centre beam, by means of the recesses in the centre beam, spring plates, having tubes thereon on which the springs rest, and attached to the beam by bolts, by which a compact and secure connection is formed, while all the necessary flexibility is preserved. =the great fair.= the american institute appears emblematical of the genius of our countrymen--unsubdued even by conflagration, and looking upon obstacles as incentives to redoubled effort. contrast the smoking ruins of niblo's with castle garden, having its whole amphitheatre enriched with a tastefully arranged collection of the most varied products of american arts and manufactures, and behold an evidence that we even inherit perseverance, enterprize and skill. we here see the embodiment of the excellence of greatness of our country--an unerring index of our future advance--if it be not that the signs of the times indicate that madness in our rulers which precedes and forebodes heaven's wrath. but it cannot, it must not be, that the blood of _labor_ shall cry from the ground of america. it must be sheathed, it must be protected. protection is nature's first law. expose the bleating flocks to the hungry beasts of the forest; cut the wings and pluck the feathers of her whom nature teaches to protect her brood from cold and rain; say to the mother to leave her babe unprotected and in free competition with all the elements of destruction, sooner than refuse the protection of our government to the hitherto flourishing american manufactures. castle garden, or more correctly castle clinton, is at the southern extremity of our city. it was built for a fort--is of a circular form, of solid mason work, surrounded by the waters of the bay--connected to that ornament of the city, the battery, by a long bridge. this bridge the managers have covered with a roof, and thus secured a very eligible and spacious apartment for the exhibition of carriages, sleighs, carts, farming implements and machinery in great variety. thence the ingress suddenly opens into view the whole interior, creating the most lively and pleasing emotions. in the columns of the scientific american we shall endeavor to give those details that will, we trust, interest our readers and promote the cause of american improvements. =baths.= after leaving the bridge, the passage way to the interior of the castle is ornamented on both sides with a pleasing display of baths--the immersion bath made of tin and of iron, and these combined with the showering apparatus. the shower baths are variously constructed, and some of them are of finished workmanship and costly material. stebbin's patent furniture shower bath presents itself first in the form of a very convenient washstand, with all its out fit; it is next easily converted into a work stand; with equal dispatch it assumes the form of a shower bath, furnished with every requisite. we regard this as an ingenious piece of furniture, that will greatly increase the use of the shower-bath, and thus add to the health of the community. =sofa bedsteads.= much ingenuity has been expended in combining the sofa and bedstead. the first that attracted our attention was that manufactured by mr. john a. robson, th st. and th avenue. it is on the double cone spring, so constructed that using it as a bed does not affect the cushion, and vice versa. the matrass or bed is by feet, without an intervening bar. it is exceedingly simple, of admirable contrivance, and of moderate price. =cutlery.= the display of american cutlery is rich, affording a most gratifying evidence of the progress of the useful arts among us. our neighbors, j. c. nixon & sons, in the sun buildings, feel quite confident that they will, as usual, carry off the premiums, particularly for their much celebrated tailor's shears. in the manufacture of engravers' tools; they challenge not only all america, but the world itself.--they manufacture for customers, from whom their articles have derived their just and solid reputation. (_to be continued._) =improved steam printing press.= we have recently seen a model of a new steam printing press, the invention of mr. wm. w. marston, a young and ingenious mechanic of this city. a mass of other matters prevents our giving a description at present; we shall probably procure an engraving, however, and publish a full description in a few days. =information to persons having business to transact at the patent office.= of models. (_continued from no. ._) sec. . the law requires that the inventor shall deliver a model of his invention or improvement when the same admits of a model. the model should he neatly made, and as small as a distinct representation of the machine or improvement, and its characteristic properties, will admit; the name of the inventor should be printed or engraved upon, or fixed to it, in a durable manner. models forwarded without a name, cannot be entered on record, and therefore liable to be lost or mislaid. sec. . when the invention is of 'a composition of matter,' the law requires that the application be accompanied with specimens of ingredients, and of the composition of matter, sufficient in quantity for the purpose of experiment. on granting anew lost patents. sec. . the third sec. of the act of march , , provides: 'sec. . and be it further enacted, that whenever it shall appear to the commissioner that any patent was destroyed by the burning of the patent office building on the aforesaid fifteenth day of december, or was otherwise lost prior thereto, it shall be his duty, on application therefor by the patentee, or other persons interested therein, to issue a new patent for the same invention or discovery, bearing the date of the original patent, with his certificate thereon, that it was made and issued pursuant to the provisions of the third section of this act; and shall enter the same of record; provided, however, that before such patent shall be issued, the applicant therefor shall deposit in the patent office a duplicate, as near as may be, of the original model, drawings, and description, with specification of the invention or discovery, verified by oath, as it shall be required by the commissioner; and such patent and copies of such drawings and descriptions, duly certified, shall be admissible as evidence in any judicial court of the united states, and shall protect the rights of the patentee, his administrators, heirs, and assigns, to the extent only in which they would have been protected by the original patent and specification.' proceedings on applications for patents, and on appeals from decisions of the commissioner. (act of , section, .) sec. . 'that on the filing of any such application (consisting of petition, specification, model, and drawings, or specimens,) and the payment of the duty hereinafter provided, the commissioner shall make, or cause to be made, an examination, of the alleged new invention or discovery; and if, on any such examination, it shall not appear to the commissioner that the same had been invented or discovered by any other person in this country prior to the alleged invention or discovery thereof by the applicant, or that it had been patented or described in any printed publication in this or any foreign country, or had been in public use or on sale, with the applicant's consent or allowance, prior to the application, if the commissioner shall deem it to be sufficiently useful and important, it shall be his duty to issue a patent therefor. but whenever on such examination it shall appear to the commissioner that the applicant was not the original and first inventor or discoverer thereof, or that any part of that which is claimed as new had before been invented or discovered or patented, or described in any printed publication in this or any foreign country as aforesaid, or that the description is defective and insufficient, he shall notify the applicant thereof, giving him briefly such information and references as may be useful in judging of the propriety of renewing his application, or of altering his specification to embrace only that part of the invention or discovery which is new. in every such case, if the applicant shall elect to withdraw his application, relinquishing his claim to the model, he shall be entitled to receive back twenty dollars, part of the duty required by this act, on filing a notice in writing of such election in the patent office; a copy of which, certified by the commissioner, shall be a sufficient warrant to the treasurer for paying back to the said applicant the said sum of twenty dollars. but if the applicant, in such case, shall persist in his claim for a patent, with or without any alteration his specification, he shall be required to make oath or affirmation anew, in manner as aforesaid; and if specification and claim shall not have been so modified as, in the opinion of the commissioner, shall entitle the applicant to a patent, he may appeal to the chief justice of the united states court for the district of columbia, who may affirm or reverse the decision of the commissioner of patents, in whole or in part, and may order a patent to issue; or he may have remedy against the decision of the commissioner of patents, or the decision of the chief justice of the united states court for the district of columbia, by filing a bill in equity in any of the united states courts having jurisdiction, as hereinafter explained. (_to be continued._) =consolation for the christian.= 'eye hath not seen; nor ear heard; neither have entered into the heart of man, the things which god hath prepared for those that love him.'-- cor. ii: . but it is said in the words following, that god hath revealed them unto us by his spirit. in this, we are not to understand, that the excellent things spoken of, are _communicated_ to men; but that by the aid of the divine spirit they are enabled to receive such sublime and brilliant ideas of the glorious things which are prepared for them, that they are filled with sublime and unspeakable joy, though they find it utterly impracticable to describe these things to another, so as to be understood. it is like the new name which no man can know, but him to whom it is given: and although, in the solicitude of those who have been favored with a view of these things, to represent them to others, the most full and expressive forms of language have been put in requisition, it has in every instance failed to convey the least correct idea on the subject: because no man can see, or in anywise appreciate the excellence of these things, without the aid of the spirit of truth. but to those who obtain such enlightened views--and every man may, or might, obtain them,--the glorious things prepared are as the 'pearl of great price,' which, when a man hath found, he is ready to sacrifice all things else,--riches, honors, friends, pleasures, reputation in the world, or even life itself,--to obtain it. neither adam nor eve, in their sinless, paradisaical state, could have had any correct idea of such delectable and glorious excellence of blessings as are prepared for these who become 'joint heirs of the son of god,' through the blood of a crucified saviour: for, had they been capable of seeing or imagining such things, they would never have fallen. there can be no question but that the glorious consolation of the faithful and obedient believers, will incomparably, not to say infinitely, excel that of the primitive state of man, or anything which could have been by man attained, if the blessed son had not suffered. let the most brilliant and soaring imagination exert its most strenuous and happy efforts in conceiving, arranging and representing to itself the highest possible state of bliss and glory, and it will fall as far short of the reality of the immortal state of the glorified saints,--the salvation purchased by the suffering of christ,--as a mere shadow of the most beautiful picture comes short of the rich coloring of the original. and this fact is well known to those who have had the beauties of the 'world to come' revealed to them by the divine spirit. these statements may appear strange to those who are accustomed to look upon the popular _reverend clergy_, fashionable church members and wealthy deacons, as choice specimens of the saints of the lord. the true, and most favored saints, are generally found among those who are subject to poverty and tribulation, in this world. but these blessings of the gospel are free for all who will conform to the requisitions plainly expressed by our savior, and recorded by the evangelist, and practicable by all who are willing to forsake all things else, for the sake of this great and everlasting salvation. * * * * * a cotton manufacturer in new-haven lost his operatives, last week, by attempting to reduce their wages. =the color printing machine.= [illustration:] introduction.--there have appeared, in modern times, but few machines, to which more importance apparently attaches, than to the one here presented. it is well known that the best paper hangings, or room-papers command from $ to $ , per piece, of eight yards, while most of those of american manufacture are sold for to cents per piece; and this difference is occasioned by the difficulty and extra labor of applying a great variety of different colors. but by means of this machine, seven, twelve, or even twenty different colors, may be accurately applied by one operation, and with less labor than is required to print with a single color, by the ordinary method; and thus the manufacturer will be enabled to sell, for cents, such patterns as ordinarily cost a dollar or more, to either import or manufacture them. explanation.--the first row of gear wheels, a b, are attached to the ends of a row of cylinders, each cylinder being inches long, and inches in diameter. these cylinders support a broad, endless apron or belt, which passes over the whole series, and supports the strip of paper as it passes through the machine to receive the colors. the second series of wheels, c d, are attached to cylinders of the same dimensions of those in the first row, and are connected to each other by intervening pinions, whereby a uniform velocity is maintained through the whole series. the peripheries of this row of cylinders are cut in figures, according to the design of the pattern to be worked. the figures are left prominent, so as to come in contact with the paper upon the apron, as the cylinder revolves; the surface between the figures, being cut away to the depth of one eighth of an inch. each of these printing cylinders contains sections of the figures to be printed, and is calculated to work a different color from the others; and the sections of figures on each cylinder are calculated to match those of the others, so as to complete the entire figure in all its colors on the paper. the entire machine is put in operation by a band, passing over the band-wheel, h. the third row of cylinders, e f, are distributing cylinders, which are put in motion by mere contact with the series below, and receives the several colors from the small cylinders in the upper rows, and distributes the same upon the prominent figures of the printing cylinders. the fourth series, i j, are called the receiving cylinders, because they receive the colors from the hoppers or reservoirs, m n, and impart them to the series below. the cylinders of the third and fourth rows, are covered with cloth, and the bottom of each hopper is so nicely fitted to its respective cylinder, that but a small quantity of each color (which passes through an aperture at the bottom of the hopper) adheres to the cloth periphery of the cylinder. the colors ordinarily used consist of various pigments, ground and mixed in water, with a solution of glue. the principles of this mode of color printing have been satisfactorily tested, though the entire machine has not yet been constructed: and any person who may be disposed to construct and enjoy the exclusive use of this invention, may have the most favorable terms. new inventions. =a new brick machine.= messrs. culbertson, mcmillen & co. of cincinnati, have recently put in successful operation, a new machine, a description of which is given in a cincinnati paper, as follows: 'a frame of fourteen moulds, one brick to each is drawn by the power of steam between two press rollers, the lower one of which enables the frame to support the pressure of the upper roller, and being run through backwards and forwards equalizes the pressure over the entire face of the brick. these, after undergoing in this mode a pressure of nearly one hundred tons to each brick, a pressure which covers clay, apparently perfectly dry, with a coat of glossy moisture, are raised above the surface of the mould by parallel levers, and are then delivered over to a bench or table by self-acting machinery, whence they are taken in barrows to the stacker at the kiln. the dry clay is shoveled into a hopper, and if more of the material is pressed into a mould than serves to make a brick, a knife which ranges with the surface of the mould, shaves off the surplus. two hands shoveling, two more taking off, and one at the barrow, constitute a gang of five persons who turn out from , to , per day of ten hours. as brick makers' days are from sun to sun, say twelve working hours per day, during the season, from to , bricks, per day, may be made by a single machine. this is, however, by no means the most important feature in the invention. in the ordinary mode of making bricks, the manufacturer cannot begin operations for the season, until the spring has so far advanced that working in wet clay will no longer chill his moulders' hands. on the same account, he loses also morning hours, until the advance of summer enables his hands to put in the whole period of daylight. he loses, also, sometimes days together--from the entire stoppage of his operations in the rainy weather, which forbids the bricks being put out to dry. in making press brick, all these difficulties are obviated. as a theory, operations in this mode can go on throughout the entire winter, frost never extending into solid clay; but as a practical business, it can be conveniently carried on two months earlier and one month later than in the ordinary mode. pressed brick, made by these machines, are also stronger than their competitive article, the last of equal hardness in burning, always giving way when struck by the pressed bricks, as i have witnessed. indeed, it cannot be otherwise, the one being porous and the other as compact as the enormous pressure employed can make it. the machine, it must be apparent, offers peculiar advantages in turning out brick without occupying the ordinary brick yard space necessary for spreading wet brick out to dry. it affords great economy in time, owing to its operations being independent of frost or rains. to every new and thriving place commencing the making of bricks, it dispenses with the necessity of bringing skilful workmen from other places--in short, it enables every man to be his own brick-maker. under these considerations, i anticipate an extensive sale of these machines, especially for places at a distance. =marble saw mills.= we are informed that a large mill for sawing marble is in course of erection at brandon, vt. the marble in that vicinity is principally of a beautiful white, and of a fine texture, though not very hard. =railroad locks.= it is reported that locks for elevating railroad trains, from one level to another, are coming into successful use in france. it appears to us to be much behind the age, since, by certain american inventions, an ordinary train may be elevated feet in five minutes, by the engine alone. [illustration: the vertical propeller.] we have alluded to this subject in a former number, and now present one of the several plans which have been introduced within the present year, although we are not fully authorised to give the name of the inventor of this particular plan. we have preferred to represent the paddles and crank unconnected with an apparent vessel or section thereof, but must require the reader to suppose that the line a b is the level of the railing of the boat, and that the crank-shaft e projects from the side, while the crank-pivot governs the motion of the walking bar d e, and with it the paddles, which are supposed to be just now dipping in the surface of the water. it will be understood that the motion of the walking bar being circular, and that of the heads of the paddles being vertical and nearly rectilinear, the motion of the blades of the paddles must be elliptical, inclining to the horizontal; and that the position of the paddles is kept so nearly vertical that they will meet with less resistance in entering or leaving the water than those of a common paddle wheel, while the atmospheric resistance to be encountered thereby is much less. there appears no reasonable doubt that this plan might be made to succeed well on a larger scale, though it is very doubtful whether any of the steamboat proprietors can be persuaded to adopt it until it has been more thoroughly tested by experiment. =a great astronomical discovery.= a late number of an astronomical journal published at altona, near hamburg, contains a long article by dr. maedler, director of the dorpat observatory, russia, well known to the astronomical world, in which he announces the extraordinary discovery of the _grand central star or sun_, about which the universe of stars is revolving, our own sun and system among the rest. this discovery, the result of many years of incessant toil and research, has been deduced by a train of reasoning and an examination of facts scarcely to be surpassed in the annals of science. he announces his discovery in the following language: 'i therefore pronounce the pleiades to be the central group of that mass of fixed stars limited by the stratum composing the milky way and alcyene as the individual star of this group, which, among all others, combines the greatest probability of being the true central sun.' by a train of reasoning, which i shall not attempt to explain, he finds the probable parallax of this great central star to be six thousandths of one second of arc, and its distance to be millions of times the distance of the sun, or so remote that light, with a velocity of millions of miles per minute, requires a period of years to pass from _the great centre_ to our sun. as a first rough approximation, he deduces the period of the revolution of our sun, with all its train of planets, satellites and comets, about the grand centre, to be _eighteen millions two hundred thousand years_. =ocean steam navigation.= the 'ocean steam company,' which has the patronage of the united states government to the amount of $ , per annum, are getting on rapidly with the first steamship of their line. she is to be completed and commence running on the first of march next. scientific american new york, october , . =employment.= it is dangerous for a man of superior ability to find himself thrown upon the world without some regular employment. the restlessness inherent in genius, being thus undirected by any permanent influence, frames for itself occupations out of accidents. moral integrity sometimes falls a prey to the want of a fixed pursuit, and the man who receives his direction in active life from the fortuitous impulse of circumstances, will be very apt to receive his principles likewise from chance. genius, under such guidance, attains no noble ends, but resembles rather a copious spring conveyed in a falling aqueduct, where the waters continually escape through the frequent crevices, and waste themselves ineffectually on their passage. the law of nature is here, as elsewhere, binding, and no powerful results ever ensue from the trivial exercise of high endowments. the finest mind, when thus destitute of a fixed purpose, passes away without leaving permanent traces of its existence; losing its energy by turning aside from its course, it becomes as harmless and inefficient as the lightning, which, of itself irresistible, may yet be rendered powerless by a slight conductor. =the editor.= write--keep writing--is the motto of an editor. if he has no ideas, he must dig for them; if he has but little time to arrange them, no matter, the work must be done. sickness may come upon him; want may stare him in the face, but he must cogitate something for the dear public. perhaps in his darkest moments, he indites a paragraph that cheers thousands. when almost desponding, his words may put courage into the hearts of millions. who would be an editor? yet he has much to encourage him. if he can call no time his own, he is not rusting out, or in unprofitable society. a faithful contributor of the public press, is a man of great influence. no person has more power than himself. he instructs tens of thousands, and leads them to virtue, to honor, to happiness. no man will have more to answer for than the conductor of a corrupt and vacillating press. =a mountain in labor.= the workmen, says a paris paper, are still busily engaged in excavating montmarte in quest of holy vases and other riches said to have been deposited there in the early days of the french revolution by the orders of the lady superior of the abbey of montmarte.--two workmen, who were at the time charged with transporting the wealth to the place designated, were never after seen, and it is supposed that they were sacrificed to the necessity of the secret. the superior, at her death, bequeathed the secret to a lady friend, who, in turn, on her death bed, divulged it to her daughter, then thirteen years of age. the child, now a sexagenary, disclosed it to the municipality. her statements have thus far been found scrupulously correct. the _cesarian_ operation is actively going on, an excavation of feet having been made, and the mountain's speedy deliverance of a mine of wealth is anticipated. may it not prove a mouse! =that editorial committee.= we are informed that the editorial committee of the national association of inventors have by _their own request_ been discharged from the supervision of the new periodical which has recently appeared under the title of 'the eureka.' =news by telegraph.= the news by the great western which arrived on wednesday week, was published within four hours in boston, new haven, springfield, albany, utica, rochester, buffalo, philadelphia and baltimore. the following beautiful extract we find in a recent number of the new york sun. it is from the pen of mr. c. d. stuart, the able correspondent of that paper, now in london. "on remarking to an englishman, that i did not see here in london as at home, the artizan, the drayman, the laborer of every kind, with a newspaper in his pocket, which at intervals in his toil he could glance at and be as learned in the condition of his country and the world as the man of fortune, he replied--"no, they have something better to do, they attend to their work." here lies the rub, and it may be a fear of the sedition of thought that has put these close hampers upon the english press. it would seem by such an argument that the differences of condition are not induced by unholy oppressions, by the trampling for ages of one class upon another until servitude became almost a birth-right--and the law of strength that proved itself in barbarous times the "supremacy" had at last from concession so long made, become the law of human justice and divine right. the steer may work under his yoke an appointed time, the slave bow mutely through his whole life, but the freeman--has he so fallen, that while the lord revels in his "club-room" and reads not only papers, but gilt edged and velvet bound books, he forsooth being a common "poor devil" not able to enjoy a tithe of his unearned luxury--has something better than reading to do. let him dig then! there are those in the young republic whose spirit begins to animate the world, who, though they toil, remember, that it was said in the beginning to all men, "thou shalt earn thy bread by the sweat of thy brow," and will read freely as they drink in the common air, and enjoy the common light. there are classes in england intelligent no doubt beyond any other people in the world--classes that enjoy the means of making themselves so, but as a mass they will in no-wise compare with their progeny, the anglo-saxons. all that they have here in the main we have got, and our wits have not been blunted by a contact with the wilderness, and the difficulties of founding an empire "in the woods." i see now more clearly than ever where our faults lie; contrast exposes them; but they are all twigs upon the rising trunk, which the keen knife of national experience, age, and the calm that must succeed the rush and tumult of our giant and boisterous infancy will cut off.--with greater pride than ever, however much i may like the old world, and especially england, i look over the ocean to america for an exemplification of what the world has not known, an _earthly_ paradise for humanity.--it is but three quarters of a century, remember, since we were nationally born: give as the fourteen hundred years that have nursed and cultivated this island, and where is the limit of our perfection and strength? on either side of that mississippi back-bone of ours to the oceans, and as far north and south as freedom and knowledge can pierce, america must be a garden and a goal, filled with every excellence and beauty, beyond which there can be no advance. we shall not live to see it, but it will come, only let us pull careful and steady. we have been dickens'd and trollop'd, and it should do us good. nothing but the grandeur that lies germinating in our heart provokes this idle spleen from our neighbors, and the moment we cool down and think and curb ourselves the rest is secure." =new glass factory.= erastus corning & co. are about establishing a factory near the ferry at troy, for the manufacture of all kinds of glass ware. the work is fast progressing, and in about four weeks they will commence blowing. it will afford employment to a large number of men, and will, no doubt, meet with that success which it certainly merits. =result of observation.= the editor of the new haven herald sets it down as a fact in natural history, proved by his experience for years, that when a traveller rides up to a toll gate, the keeper--if a man, invariably brings out a box, or a handful of change; but if a woman, she comes out and takes the traveller's coin, and then goes back for the change. * * * * * snags and other obstructions in the western rivers, are now denominated _polk stalks_. =the science of astronomy.= descriptive astronomy. mercury, the nearest planet to the sun, is a globe of about miles in diameter, rotating on its axis in hours and - minutes, and revolving round the central luminary, at a distance of , , of miles, in days.--from the earth it can only be seen occasionally in the morning or evening, as it never rises before, or sets after the sun, at a greater distance of the time than hour and minutes. it appears to the naked eye as a small and brilliant star, but when observed through a telescope, is horned like the moon, because we only see a part of the surface which the sun is illuminating. mountains of great height have been observed on the surface of this planet, particularly in its lower or southern hemisphere. one has been calculated at - miles in height, being about eight times higher, in proportion to the bulk of the planet, than the loftiest mountains upon earth. the matter of mercury is of much greater density than that of the earth, equalling lead in weight; so that a human being placed upon its surface would be so strongly drawn towards the ground as scarcely to be able to crawl. venus is a globe of about miles in diameter, or nearly the size of the earth, rotating on its axis in hours, minutes, and seconds, and revolving round the sun, at the distance of , , of miles in days.--like mercury, it is visible to an observer on the earth only in the morning and evening, but for a greater space of time before sunrise and after sunset. it appears to us the most brilliant and beautiful of all the planetary and stellar bodies, occasionally giving so much light as to produce a sensible shadow. observed through a telescope, it appears horned, on account of our seeing only a part of its luminous surface. the illuminating part of venus occasionally presents slight spots. it has been ascertained that its surface is very unequal, the greatest mountains being in the southern hemisphere, as in the case of both mercury and the earth. the higher mountains in venus range between and miles in altitude. the planet is also enveloped in an atmosphere like that by which animal and vegetable life is supported on earth; and it has consequently a twilight. venus performs its revolution round the sun in days. mercury and venus have been termed the inferior planets, as being placed within the orbit of the earth. the earth, the third planet in order, and one of the smaller size, though not the smallest, is important to us, as the theatre on which our race have been placed to 'live, move, and have their being.' it is miles in mean diameter, rotating on its axis in hours, at a mean distance of , , of miles from the sun, round which it revolves in days, hours, minutes, and seconds. as a planet viewed from another of the planets, suppose the moon, 'it would present a pretty, variegated, and sometimes a mottled appearance. the distinction between its seas, oceans, continents, and islands, would be clearly marked; they would appear like brighter and darker spots upon its disc. the continents would appear bright, and the ocean of a darker hue, because water absorbs the greater part of the solar light that falls upon it. the level plains, (excepting perhaps, such regions as the arabian deserts of sand) would appear of a somewhat darker color than the more elevated and mountainous regions, as we find to be the case on the surface of the moon. the islands would appear like small bright specks on the darker surface of the ocean; and the lakes and mediterranean seas like darker spots or broad streaks intersecting the bright parts, or the land. by its revolution round its axis, successive portions of the surface would be brought into view, and present a different aspect from the parts which preceded,'--(dick's celestial scenery, .) the form of the earth, and probably that of every other planet, is not strictly spheroidal; that is, flattened a little at the poles, or extremities of the axis. the diameter of the earth at the axis is miles less than in the cross direction. this peculiarity of the form is a consequence of the rotatory motion, as will be afterwards explained. [illustration: latest news] =late foreign news.= the steamer hibernia arrived at boston on saturday last, thirteen days from liverpool. the british government and people have manifested so much violent opposition to the marriage of the youngest son of louis phillipe to a sister of the queen of spain, that the celebration of the nuptials has been postponed for the present, if not forever; and there is apparent danger of a rupture between england and france on this account. in spain, don carlos having escaped from imprisonment, it is expected that a serious insurrection will immediately take place. property to the amount of $ , has been destroyed by incendiary fires at leipsic. a line of electric telegraph has been put in operation between brussels and antwerp. twenty thousand bales of cotton were sold at liverpool on the th of september. =latest from the army.= according to recent intelligence by private letters, gen. kearney has taken quiet possession of santa fe, notwithstanding the considerable preparations which the mexicans had made to defend it. gen. armijo had assembled troops to defend the canon pass, but on account of the disaffection and insubordination of his officers and men, he was constrained to retreat on the approach of a few companies of americans. gen. taylor had advanced steadily, though slowly on monterey, and has probably ere this, taken possession, notwithstanding the strong force, and full supply of well mounted cannon, concentrated to oppose him. should he prove successful in this, it would seem that mexico is destined to fall under the protection of the united states, whether our government desires it or not. what can we do? the mexicans will neither treat nor fight; and although our armies move as slow as possible, they cannot well avoid progressing through the country in time, and are bound to furnish protection as far as they go. we shall see. =the sea and wave roaring.= the steamer great western, which arrived at this port last week, reports having encountered one of the most terrific storms ever known on the atlantic ocean. capt. mathews is said to have remarked that at three different times the ship was approached by seas of such magnitude and power that he thought destruction inevitable; but unexpectedly each broke just before reaching the vessel. the passengers assembled in the cabin where they joined in religious service, and in the solemn administration of the lord's supper. their lives were preserved, but some of them appeared to forget their obligations to their preserver very quick after getting safe on shore. =an american slave in england.= douglas, who escaped from slavery and found his way to england, has received marked attention from the nobility and gentry of england. he has attended their soirees, occupied the most honorable positions at their dinner parties, rode in their carriages, flirted with their daughters, walked arm in arm through their gardens with lords, viscounts, counts and mayors of cities. * * * * * many of the girls employed in the mills of the nashua corporation, have refused to work by candlelight. they may be right. the =scientific american=. persons wishing to subscribe for this paper, have only to enclose the amount in a letter directed (post paid) to munn & company, publishers of the scientific american, new york city. terms.--$ a year; one dollar in advance--the remainder in months. _postmasters_ are respectfully requested to receive subscriptions for this paper, to whom a discount of per cent will be allowed. any person sending us subscribers for months, shall receive a copy of the paper for the same length of time. observations on the more recent researches concerning the operations of the blast furnace in the manufacture of iron. by dr. j. l. smith. the great difference existing between metallurgical operations of the present day, and those of a former period, is owing chiefly to the ameliorations produced by the application of the science of chemistry to the _modus operandi_ of the various changes taking place during the operations, from their commencement to their termination. copper and some other metals are now made to assume forms in the chemist's laboratory, that formerly required great artistical skill for their production--the chemist simply making use of such agents and forces as are at his command, and over which he has, by close analytical study, acquired perfect control. our object, at present, is only to advert to the chemical investigations more recently made on the manufacture of iron, treating of those changes that occur in the ore, coal and flux, that are thrown in at the mouth of the furnace, and in the air thrown in from below. for most that will be said on this subject, we are principally indebted to the recent interesting researches of m. ebelman. the importance of a knowledge of the facts to be brought forward, in this article, will be apparent to every one in any way acquainted with the manufacture of iron. it will be seen that the time is not far distant when the economy in the article of fuel will amount in value to the present profit of many of the works. the consequences must be, that many of those works that are abandoned will be resumed, and others erected in localities formerly thought unfit. it is well known that the blast furnace is the first into which the ore is introduced, for the purpose of converting it into malleable iron, and much, therefore, depends upon the state in which the pig metal passes from this furnace, whether subsequent operations will furnish an iron of the first quality or not. in putting the blast furnace into operation, the first step is to heat it for some time with coal only. after the furnace has arrived at a proper temperature, ore, fuel and flux, are thrown in alternately, in small quantities, so as to have the three ingredients properly mixed in their descent. in from to hours from the time when the ore is first thrown in, the entire capacity of the furnace, from the tuyer to the mouth, is occupied with the ore, fuel and flux, in their various stages of transformation. in order to explain clearly, and in as short space as possible, what these transformations are, and how they are brought about, we may consider:-- . the changes that take place in the descending mass, composed of ore, fuel and flux. . the changes that take place in the ascending mass, composed of air and its hygrometric moisture, thrown in at the tuyer. . the chemical action going on between the ascending and descending masses. . the composition of the gases in various parts of the furnace during its operation. . the causes that render necessary the great heat of the blast furnace. . _changes that take place in the descending mass, composed of ore, coal and flux._--by coal is here meant charcoal; when any other species of fuel is alluded to, it will be specified. in the upper half of the fire-room the materials are subjected to a comparatively low temperature, and they lose only the moisture, volatile matter, hydrogen, and carbonic acid, that they may contain; this change taking place principally in the lower part of the upper half of the fire-room. in the lower half of the fire-room, the ore is the only material that undergoes a change, it being converted wholly or in part into iron or magnetic oxide of iron--the coal is not altered, no consumption of it taking place from the mouth down to the commencement of the boshes. from the commencement of the boshes down to the tuyer, the reduction of the ore is completed. very little of the coal is consumed between the boshes and in the upper part of the hearth; the principal consumption of it taking place in the immediate neighborhood of the tuyer. the fusion of the iron and slag occurs at a short distance above the tuyer, and it is in the hearth of the furnace that the iron combines with a portion of coal to form the fusible carburet or pig-iron. it is also on the hearth that the flux combines with the siliceous and other impurities of the ore. this concludes the changes which the ore, coal and flux, undergo, from the mouth of the furnace to the tuyer. if the fuel used be wood, or partly wood, it is during its passage through the upper half of the fire-room that its volatile parts are lost, and it becomes converted into charcoal. m. ebelman ascertained that wood, at the depth of ten feet, in a fire-room twenty-six feet high, preserved its appearance after an exposure for - of an hour, and that the mineral mixed with it preserved its moisture at this depth; but three and a half feet lower, an exposure of - hours reduced the wood to perfect charcoal, and the ore to magnetic oxide. the temperature of the upper half of the fire-room, when wood is used, is lower than in the case of charcoal, from the great amount of heat made latent by the vapor arising from the wood. in the case of bituminous coal, bunsen and playfair find that it has to descend still lower before it is perfectly coked. after the wood is completely charred, or the coal become coked, the subsequent changes are the same that happen in the charcoal furnaces. _to be continued._ =animalculae in water.= [illustration:] the fact is generally known that nearly all liquids contain a variety of minute living animals, though in some they are too small for observation, even with a microscope. in others, especially in water that has been long stagnant, these animals appear not only in hideous forms, but with malignant and voracious propensities. the print at the head of this article purports to be a microscopic representation of a single drop of such water, with the various animals therein, and some of the inventors and venders of the various improved filters for the croton water, would have no objection to the prevalence of the opinion that this water contains all the variety of monsters represented in this cut. but the fact is far otherwise; and it is doubtful whether these animals could frequently be detected in the croton water, with the best solar microscope. nevertheless, the fact is readily and clearly established that the croton water contains a quantity of deleterious matter, which is arrested by the filters; and, on this account, we cheerfully and heartily recommend the adoption of filters by all who use this water, from either the public or private hydrants. to this end we would call the special attention of our city readers to the improved filters noticed under the head of "new inventions." =length of days.= at berlin and london the longest day has sixteen and a half hours. at stockholm and upsal, the longest has eighteen and a half hours, and the shortest five and a half. at hamburg, dantzic, and stettin, the longest day has seventeen hours, and the shortest seven. at st. petersburg and tobolsk, the longest has nineteen, and the shortest five hours. at toreno, in finland, the longest day has twenty-one hours and a half, and the shortest two and a half. at wandorbus, in norway, the day lasts from the st of may to the d of july, without interruption; and in spitzbergen, the longest day lasts three months and a half. =excitement of curiosity.= the editor of the cincinnati enquirer, having been one of a recent excursion party on the opening of a new section of railroad, remarks on the occasion, 'it is really amusing to see the sensation a train of railroad cars produces on all animate beings, human and brute, for the first few times it passes over a section of road. we saw herds of cattle, sheep, and horses, stand for a few seconds and gaze at the passing train, then turn and run for a few rods with all possible speed, stop and look again with eyes distended, and head and ears erect, seemingly so frightened at the tramp of the iron horse as to have lost the power of locomotion. men women and children also seemed dumbfounded at the strange and unusual spectacle. as the cars came rumbling along early in the morning, they seemed to bring everybody out of bed, all eager to catch a glance as we whirled past. old men and women, middle-aged and youth, without waiting to put on a rag in addition to their night gear, were seen at the doors, windows and round the corners of log huts and dwellings, gaping with wonder and astonishment at the new, and to them grand and terrific sight.' [communicated.] at the last special meeting of the national association of inventors, called to hear the report on the rights and duties of the editors of the eureka, on a resolution offered by one of the editorial committee who had been dissatisfied by the proceedings of the 'acting editors,' and refused to attend their sittings, it was reported that the 'acting editors,' had exceeded their authority, and a majority of the editorial committee resigned and a resolution was passed that the resignation should be published in the eureka, but it has not appeared. mr. kingsley, one of the 'acting editors,' spoke at the said meeting of having consulted counsel who had declared that the association were under a legal obligation to furnish messrs. kingley & pirsson with matter for publication in the eureka, and on the understanding that they had advanced money they were allowed to have the first use of the reports and advertisements of the association. but as they in effect refuse to publish a resolution of great importance to the reputation of all the parties interested, it is left for the public to decide whether the 'acting editors' are in any respect entitled to the name they have assumed for their paper. one of the editorial committee. humorous. =to my sweetheart.= you're a broth of creature, in form and in feature,-- it's myself that now tells you that same, and sure, by my troth, i'll not be very wroth. if you'll plaze me by changing your name what a swate little wife, as a partner for life, my darlint, 'tis you might be living; and i'm just the boy, to wish you much joy, when your heart it's to me you'll be giving. i'm half dead--botheration! with sad consternation-- of your flirting it is that i'm speaking; so plaze to be thinking, when you're winking and blinking. it's my own honest heart that you're braking. the divil a haper, will i stand of a caper,-- 'twould kill me to find you deceiving; by my sowl and i'd die, and that same is no lie, before i'd be kilt by me grieving. then spake but the word. my nate little bird, that you're niver a man's but mine; and straight to the praist, it's myself that'll haste, to make you my _swate waluntine_! [_teddy magowan._ =boys and men.= a youthful volunteer, the other day, out in arkansas, was taunting a married gentleman, who had a wife and three small children depending upon him, for not rallying to the standard of his country, soon after the requisition upon that state arrived. 'tom,' said our friend, 'you _boys_ can whip the mexicans, but should old england take a hand in the pie, _i'll_ join, for it will require _men_ to whip the english.' =trusting too long.= we recollect that a weekly paper was started, some years ago, in one of the western states, the terms of which were $ , in advance, $ at the end of the year--to which the editor jocosely added in a paragraph, 'and $ if never paid.' we think that most of his subscribers took the paper upon the latter terms, since it has been non est. he played a joke upon himself. =business stand.= a frenchman, being about to remove his shop, his landlord inquired the reason, stating, at the time, that it was considered a very good stand for business. he replied, with a shrug of the shoulders, "oh, yes, he's very good stand for de businis; by gar, me stan' all day, for nobody come to make me _move_!" =plain directions.= represent me in my portrait, said a gentleman to his painter, with a book in my hand reading aloud. paint my servant also in a corner where he cannot be seen, but in such a manner that he may hear me when i call him. =homogeneous.= joe snooks, seeing some farmer's boys employed, some at hoeing and others at mowing, in the same field, remarked that they were a _hoe-mow_-geneous set of fellows. * * * * * the louisville journal, philosophizing on the recent commencement of several newspapers, gives the following poetic remark: 'income and ink'em, although you may link'em, are not such first cousins as some folks may think'em.' * * * * * we did not expect to mention large peaches again; but the louisville journal speaks of a lot which measured nearly _twelve inches_ each, in circumference. =proposition of a new patent law.= the following remarks and proposition, which we copy from the 'farmer and mechanic,' was written by a prominent member of the national association of inventors, and expresses the sentiments of a large majority of the members of that association. no person who carefully examines the subject, can fail of seeing that the cause of justice and equity, as well as the advance of improvement, would be promoted by the substitution of the principles therein expressed, in place of some of those embraced in the existing patent laws of the united states. "we advance the principle, which may be novel to some, that if the inventor apply genius, time, toil, and capital, to produce anything he may consider valuable, he has the same right to the exclusive use and enjoyment of it as the man who may apply time, and toil, and capital, without genius. that the application of genius does not divest him of any right enjoyed by all others in society. it is true, the creations of genius are sometimes intangible, but that is no objection; all rights are abstractions, until embodied in constitutions and laws, and rendered practical by penalties. if an inventor can define the limits of his claim, he is entitled to protection in it just the same as when a deed is put on record, limiting the boundaries of a lot of ground. all rights to real property are traced back to original discovery and occupancy, and now all the inventor desires, or nearly all, in any patent law, is a simple registry, just as we find in our halls of record. the commissioner of patents should be called the register of patents. indeed, grants of land, as they are termed, have frequently been registered by the name of patents, in our halls of records, so strong is the analogy, if not perfect similarity. then what should be the patent law? we answer, by sections, at once. the first should be declaratory of the rights of inventors, as follows: sec. . the application of capital, time, skill and ingenuity, to the production of new and useful discoveries, shall be protected under the th article of the amendments to the constitution, which forbids private use without the consent of the owner, and for public use without just compensation. sec. . should any invention or discovery be deemed of great importance to the general prosperity, its value shall he appraised on the requisition of the secretary of state, which value, which ascertained, as hereinafter provided, shall be paid to the inventor from the treasury of the united states, and, until this payment shall take place, the discovery of any inventor duly qualified to take out a patent, shall remain his property, and inalienable without his consent or the consent of his legal representatives. sec. . any inventor or discoverer who may desire a patent for any discovery of his own, shall make oath or solemnly affirm thereto, and any specification, drawing or model, he may see fit to deposit with the register of patents, shall be received by him and recorded, as a matter of evidence of original right. sec. . there shall be no salaried examiners of patents, but each patentee may contract on any terms he may see fit with any patent agent or examiner, to examine the records of the patent office, on the payment of ten dollars fee for the use of the books and privilege of the patent office, and no more fees than this first $ shall be charged on any single patent, excepting five dollars each for every record of transfer of rights or parts of rights. nor shall the fees be raised until it may be discovered that they will not support the expenses of the patent office. and it is provided, no expenses for the improvement of agriculture, or any purpose foreign to the business of the registry of patents, and the necessary books and buildings, and salaries of the register, librarian and two clerks and door-keeper, shall be charged upon the patent fund. sec. . the commissioner of patents shall give advice of a scientific and legal character as he may be desired and qualified to do, to inventors. he may guaranty the originality of any invention at his own risk, at any price be may agree upon with any inventor to give certificates thereof, and this shall not interfere with his regular salary. but it is provided that the commissioner shall not in any manner prevent others from examining and guarantying the originality of any invention for which a patent may be desired. and it is also provided that any commissioner, register, clerk, attorney, examiner or agent, who may give a guaranty or warrant of the novelty of any invention shall be held responsible in costs on any information to be filed by any party who may feel himself aggrieved, to rescind the patent which may not be an original invention of the claimant so guarantied. sec. . to rescind a patent, any party feeling himself aggrieved may file information in the district court of the united states, of the district in which the patentee resides, notifying the patentee of such information filed, with what the former intends to prove, and where the patentee may discover the evidence relied upon by the informer, on which, the patentee may surrender his patent without costs should he so elect. but should the patentee determine to stand trial, he shall plead to such information within twenty days, denying the allegations of the informer, on which the trial shall proceed in its regular order on the calendar, and the patentee, if found wilfully and knowingly a monopolizer of the public rights, shall suffer costs and the reasonable expenses and counsel fee of the informer. and if such inventor shall make oath he has not been enabled to examine the proofs on which the informer relies to rescind his patent, he shall be allowed such further time as the court having jurisdiction may prescribe. and the court may make an order to the informer to exhibit fully his evidence of priority of invention, and no other evidence than has been exhibited to the inventor excepting rebutting, shall be introduced on the trial to rescind the patent. sec. . the commissioner of patents shall collect and keep in the patent office all the scientific works published and useful for references, and pay the expenses of the same from the patent fund. but the commissioner shall not subscribe for more than three copies of any publication for the use of the office as aforesaid out of the patent fund. sec. . the application of any known machinery or matter of combination of machinery, or matter to new purposes or old purposes after a new method, or any means by which useful results are to be more advantageously produced than formerly, shall be the subject of a patent. sec. . a method, plan, design, or any new and useful idea, which can be defined, shall be the subject of a patent. sec. . a simple change of form shall not entitle any one to evade the patent of any inventor by a new patent. the above are the principal improvements desired by inventors. some think it not well to ask for all they want at once, but we think differently, for it will be said hereafter, when new amendments are desired, 'gentlemen, you petitioned for the very provisions you now seek to have annulled. your own committee was here at washington assenting.' what answer will there be to this? none can be made without confusion of face for having over assented to a wrong. we do not desire to censure the committee charged with the mission to washington.--they have thought to act prudently and for the greatest good. we differ only on the real expediency of the case. we do not believe that such men as benton, calhoun, and other kindred spirits, ask or desire anything but what they think is right. they will not sacrifice their reputation against a body of men to whom the republic owe so much, and who have so long suffered in silence. the law as it now stands, is an improvement on the former law, and considering how low was the state of morals in former times respecting inventors, such sentiments as have been advanced by judge woodbury, and which are in spirit the same as the above, are destined ultimately to prevail. and those who choose to record their names in opposition are free to do so, as are also the tribe of persecutors who in all ages have stoned the prophets. the principle endeavored to be followed throughout, is that of the common and statutes laws respecting the rights to real property. it may tend to create litigation, as to claims which are now refused entirely, but if no litigation or less is the grand desideratum, why not establish a dictatorship at once? the _ipse dixit_ of one man will then prevent all argument. but the rights of property and jury trial in all cases are ours by the constitution--and equally are we entitled by the constitution to the pursuit of happiness and wealth in ærial regions as on the common earth--and if we may not be divested of our other property without certain laws and a fair jury trial, why should we be of patent property? and if patent agents presume to beguile honest inventors, why should they not be held responsible? they may refuse to back their operation by a guaranty, but then the inventor has a right to know it, and to know he has a remedy, should they do so improperly. the clerk of one of our courts guarantied the searches of one of his clerks as to a piece of real property, and had to pay some ten thousand dollars, and why should it not be so. when a tailor makes a coat he warrants it to fit, and when a surgeon sets a leg unscientifically he is also responsible in damages to his patient, and as is an attorney for negligent practice. holding examiners responsible will leave the patent office open to the filing of new claims at the same time that it will prevent a world of litigation, favoritism and corruption. we are not striking at our present worthy commissioner, mr. burke. we are friendly to him. but the more honest a man may be, the sooner will he find himself displaced, if the office he holds may be used to grasp a vast amount of patronage and property.' advertisements. [**hand pointing right]this paper circulates in every state in the union, and is seen principally by mechanics and manufacturers. hence it may be considered the best medium of advertising, for those who import or manufacture machinery, mechanics tools, or such wares and materials as are generally used by those classes. the few advertisements in this paper are regarded with much more attention than those in closely printed dailies. advertisements are inserted in this paper at the following rates: one square, of eight lines one insertion, $ " " " " two do., " " " " three do., " " " " one month, " " " " three do., " " " " six do., " " " " twelve do., terms:--cash in advance. * * * * * general agents for the scientific american. new york city, geo. dexter " " wm. taylor & co. boston, messrs. hotchkiss & co. philadelphia, messrs. colon & adriance. local agents. albany, peter cook. baltimore, md., s. sands. cabotville, mass., e. f. brown. hartford, ct., e. h. bowers. lynn, mass., j. e. f. marsh. middletown, ct., wm. woodward. norwich, ct., safford & parks. new haven, ct., e. downes. new bedford, mass., wm. robinson & co. newark, n.j. j. l. agens. patterson, n.j., l. garside. providence, r.i., h. & j. s. rowe. springfield, mass., wm. b. brocket. salem, mass., l. chandler. troy, n.y., a. smith. taunton. mass., w. p. seaver. worcester, mass., s. thompson. boston, jordon & wiley. newark, n. j., robert rashaw. williamsburgh, j. c. gander. travelling agents. o. d. davis, john stoughton, john murray, sylvester dierfenorf. city carriers. clark selleck, squire selleck, nathan selleck. persons residing in the city of brooklyn, can have the paper left at their residences regularly, by sending their address to the office, fulton st., d. floor. =american and foreign patent agency.= no. chambers street, new york. joseph h. bailey, engineer and agent for procuring patents, will prepare all the necessary specifications, drawings, &c. for applicants for patents, in the united states or europe. having the experience of a number of years in the business, and being connected with a gentleman of high character and ability in england, he has facilities for enabling inventors to obtain their patents at home or abroad, with the least expense and trouble. the subscriber, being practically acquainted with all the various kinds of drawing used, is able to represent machinery, inventions, or designs of any kind, either by authographic drawing, or in isometrical, parallel, or true perspective, at any angle best calculated to show the construction of the machinery of design patented. to those desiring drawings or specifications, mr. b. has the pleasure of referring to gen. wm. gibbs mcniel, civil engineer, prof. renwick, columbia college, prof. morse, jno. lee. residence, no. carroll place; office, no. chambers street. oct tf * * * * * black lead pots!--the subscriber offers for sales, in lots to suit purchasers, a superior article of black lead pots, that can be used without annealing. the price is low, and founders are requested to make a trial. samuel c. hills, to ndv patent agent, platt street. state of new york. secretary's office, albany, july , . to the sheriff of the city and county of new york: sir--notice is hereby given, that at the next general election, to be held on the tuesday succeeding the first monday of november next, the following officers are to be elected, to wit:--a governor and lieutenant governor of this state. canal commissioners, to supply the place of jonas earll, junior, and stephen clark, whose terms of office will expire on the last day of december next. a senator for the first senatorial district, to supply the vacancy which will accrue by the expiration of the term of service of john a. lott on the last day of december next. a representative in the th congress of the united states for the third congressional district, consisting of the st, d, d, th and th wards of the city of new york. also a representative in the said congress for the fourth congressional district, consisting of the th, th, th and th wards of said city. also a representative in the said congress for the fifth congressional district, consisting of the th, th and th wards of said city. and also a representative in the said congress for the sixth congressional district, consisting of the th, th, th, th, th and th wards of said city. also the following officers for the said county, to wit: members of assembly, a sheriff in the place of william jones, whose term of service will expire on the last day of december next. a county clerk in the place of james connor, whose term of service will expire on the last day of december next, and a coroner in the place of edmund g. rawson, whose term of service will expire on the last day of december next. yours, respectfully, n. s. benton, secretary of state. * * * * * sheriff's office, new york, august d, . the above is published pursuant to the notice of the secretary of state and the requirements of the statute in such case made and provided for. wm. jones, sheriff of the city and county of new york. [illustration: hand pointing right]all the public newspapers in the county will publish the above once in each week until election, and then hand in their bills so that they may be laid before the board of supervisors, and passed for payment. see revised statutes, vol. , chap. vi. title d, article d--part st, page . aug =brass foundry.= james kenneard & co. respectfully inform their friends and the public that they are prepared to furnish all orders for brass and composition castings, and finishing in general at the shortest possible notice. n.b. all orders for rail road, factory and steamboat work from any distance, will be thankfully received and attended to with despatch and on reasonable terms. [illustration: hand pointing right]patterns made to order. james kenneard & co. oct. m* - chrystie st. new york. [illustration: hand pointing right]notice--r. c. wetmore & co. return their thanks to the fire department & police, for the zealous exertions used by them in saving the property in the store no. water street, at the fire this evening. r. c. wetmore & co. desire especially to acknowledge the aid of his honor the mayor, in preserving their books and papers. tuesday night. prosper m. wetmore, navy agent, begs to return his grateful acknowledgment to his honor the mayor, the members of the fire department, and municipal police, for the assistance rendered him in saving all the books and papers of the navy agency from the fire this evening, tuesday night. notice. the office of the navy agent is removed for the present to the back office of the store no. broad street. prosper m. wetmore, navy agent. [illustration: hand pointing right]all city papers please copy, and send bill. o t * * * * * new improvement.--m. h. mansfield, of mifflintown, juniata co., pennsylvania, has invented a new clover hulling machine, which is one of the best inventions of the kind now in use. this machine will hull forty bushels of seed per day. persons wishing to manufacture them can procure the right on moderate terms from the inventor. for further particulars, address. martin h. mansfield, oct. t* mifflintown, juniata co. pa. * * * * * copper smith!--the subscriber takes this method of informing the public that he is manufacturing copper work of every description. particular attention is given to making and repairing locomotive tubes. those at a distance, can have any kind of work made to drawings, and may ascertain costs, &c., by addressing l. r. bailey, cor. of west and franklin sts., n. y. n.b.--work shipped to any part of the country. to dv * * * * * * =electricity.= smith's celebrated torpedo, or vibrating electro magnetic machine --this instrument differs from those in ordinary use, by having a third connection with the battery, rendering them much more powerful and beneficial. as a curious electrical machine, they should be in the possession of every one, while their wonderful efficacy as a medical agent, renders them invaluable. they are used with extraordinary success, for the following maladies. =rheumatism=--palsy, curvature of the spine, chronic diseases, tic-doloureaux, paralysis tubercula of the brain, heart, liver, spleen, kidneys, sick-headache. =toothache=--st vitus dance, epilepsy, fevers, diseases of the eye, nose, antrum, throat, muscles, cholera, all diseases of the skin, face, &c. =deafness=--loss of voice, bronchitis, hooping cough. these machines are perfectly simple and conveniently managed. the whole apparatus is contained in a little box inches long, by wide and deep. they may be easily sent to any part of the united states. to be had at the office of the scientific american, fulton st, nd floor, (sun building) where they may be seen in operation, at all times of the day and evening. * * * * * gold pens!!--in consequence of the increased facility afforded by machinery for the manufacture of my gold pens, i am enabled to furnish them to the trade, at a much less price than they have heretofore obtained them through my agent. those purchasing direct of the manufacturer will have the double advantage of the lowest market price, and the privilege of returning those that are imperfect. in connection with the above, i am manufacturing the usual style of penholder, together with my patent extension penholder with pencil. all orders thankfully received, and punctually attended to. a. g. bagley, sept. tf broadway, n. y. =engraving on wood.= neatly and promptly executed at the office of the scientific american, fulton st, three doors from the sun office. designs, drawings of all kinds for patents, &c., also made, as above, at very low charges. [illustration: curious arts] =labor to make a watch.= mr. dent, in a lecture delivered before the london royal institute, made an allusion to the formation of a watch, and stated that a watch consists of pieces; and that trades, and probably persons are employed in making one of these little machines. the iron of which the balance wheel is formed, is valued at something less than a farthing; this produces an ounce of steel, worth - pence, which is drawn into , yards of steel wire, and represents in the market, _l._ _s._; but still another process of hardening this originally a farthing's worth of iron, renders it workable into , balance springs, which will realize, at the common price, of _s._ _d_ each _l_. _s_, the effect of labor alone. thus it may be seen that the mere labor bestowed upon one farthing's worth of iron, gives it the value of _l._ _s_, or $ , , which is , times its original value. =mule boats.= this kind of conveyance is, we believe, peculiar to the illinois river, for we never remember to have seen one belonging to any other stream. a year or two since, we were perfectly astonished at beholding the first one that ever arrived in this port; but now they are as common as the species usually termed _broad horns_, and their appearance creates about as much surprise and curiosity among the more aristocratic order of steam and sail. a genuine mule boat is not unlike an ocean steamer, as they are susceptible of being propelled both by steam and wind; with this difference, the mule-boat steam is generated upon the tread-mill plan, and by the united exertions of some half dozen quadrupeds, generally of the long-eared kind. to this treading or pulling apparatus are attached cylinder, pitt-man, boilers, &c., in the shape of some three or more cog-wheels, and immediately connected with them is a couple of shafts, which give a rotary motion to a couple of water-wheels, one on each side, and which usually propel a keel about feet in length, and of about tons burthen; over it is a roof and covering, usually called a cargo box, to protect the inside from the weather, and the whole making an appearance similar to an ohio river keel boat, with the exception of a space left her to operate in. the difficulty and danger attending the management of a boat propelled by steam, is upon the mule boat entirely dispensed with. there is no firing up, or blowing up; all that is necessary, when wishing to commence a journey, is to start, and when tired of going, all that is to be done is to stop the mules; in giving a lick ahead, they are all made to bounce at once, and in giving a lick back, they are turned around and made to pull the other way: and should the wind prove favorable, by means of a mast, with which they are all provided, sails can be hoisted, and the the double power of mules and wind be put in requisition. this description of boat is getting to be quite fashionable on the illinois and tributaries, and some two or three extend their trips to this city. they are a great benefit in low water, as they are of exceeding light draught, and the running of them is attended with but trifling expense. we learn that several new ones are in a state of completion, on the line of the illinois, intended as regular traders up the sangamon river, and from the head of navigation on the illinois to this city. there is nothing like enterprise, or a mule boat on the illinois, in a low stage of water, to get along.--[st. louis new era. =discovery of glass.= 'as some merchants,' says pliny, 'were carrying nitre, they stopped near a river which issues from mount carmel. as they could not readily find stones to rest their kettles on, they used for this purpose some of these pieces of nitre. the fire, which gradually dissolved the nitre, and mixed it with the sand, occasioned a transparent matter to flow, which in fact was nothing less than glass.' =pumping the water out of lake michigan.= it is well known to our readers that, by an arrangement with the english bond holders, the state of illinois has given over to them the unfinished canal, from the waters of lake michigan, at chicago, to the illinois river.--they are about completing it, but the principal difficulty now is, to supply it with water, owing to the level of the lake being _eight_ feet below the bottom of the canal. to overcome this, the present company, after various propositions, finally bethought themselves of raising the water of the lake, so as to supply the canal. they went to messrs. knapp & totten, of this city, and furnished them with a data to calculate whether it could be done, and what force and what machinery would accomplish it. these gentlemen soon furnished an answer to build some powerful machinery for that purpose,--a steam engine and _eight_ pumps of four and a half bore and six feet stroke. we are glad to hear that this eminently scientific firm have been selected to execute this order. their shop and mechanical force are not excelled by any establishment in the united states.--[pittsburg gaz. =the self-regulating ventilator.= [illustration:] explanation:--this is a cheap and simple but scientific apparatus for regulating the air-vent of a common, cheap stove, according to the temperature of the atmosphere in the room in which it is located. the draught door is a plain iron door, hung by a common hinge joint at the upper end; and to the front of the hinge is attached a piece of brass wire, which extends vertically nearly to the top of the room, and is connected at b to a horizontal brass wire c d. this is the only apparatus required, but must be so adjusted as to allow the door to be closed, or nearly so, when the temperature is about right. if the temperature rises above that point, the horizontal wire will immediately expand so as to allow the door to close. but as soon as the temperature begins to fail, the wire contracts and opens the vent. on this principle the apparatus will readily find a medium, and there remain, varying only occasionally to accommodate itself to the variations of the quantity of fuel in the stove. the entire expense of this apparatus, exclusive of the stove, will not exceed cents. it is generally conceded that a large portion of cases of colds, coughs, &c. are occasioned by irregularities of the temperature of sitting-rooms but with this plan of regulation this evil may be avoided without any material expense. =new paper mill.= mr. c. c. p. moses has erected a line brick building, by feet, three stories high, on the site of the old foundry, at dover, n. h., $ , to $ , . the rooms are constructed and furnished in a complete manner for carrying on the paper making business in all its departments. the works are nearly completed, and will be in operation in five or six weeks. =new mill at lowell.= the merrimack company have in progress of erection the largest mill in lowell, and which is calculated to employ from to operatives. the building is nearly finished, and the machinery is to embrace the latest improvements in this or any other country. =machine shop.= a new machine shop is about commencing operation in norwich: about half a mile northeast from the railroad depot. the building is by feet, and is calculated to employ hands in the manufacture of steam engines and manufacturing machinery. the work at this shop will be finished in the best style and at moderate prices. =ornamental kites.= [illustration:] this month being considered as one of the best for flying kites, we may indulge our young friends with an article on that subject. the principle on which kites are made to ascend by the action of the wind, is too well understood, even by children, to require explanation. we shall merely introduce and describe some fancy models of kites, which are not often seen. the pattern, fig. , which is the figure called a star, is very easily made. the frame consists simply of the strips, or rods of light wood; spruce timber, willow twig's--and interlocked, as shown in the cut; so that each rod shall pass alternately over and under the other rods at each intersection. these rods being lashed together at the points, the whole frame is covered with white or yellow paper, and the twine is attached to three of the angles of the star. the eagle, fig. , is but little more difficult; a rod extends from the beak to the tail, and is crossed by another which extends from tip to tip of the wings. the rods being lashed together, a small thread is drawn from the place of the head of the eagle, to the two extremities of the wings, and thence to the leeward end of the centre rod. this thread should be white or light blue, and will not be visible when aloft; but the form of the eagle should be made of black, dark or brown paper. the paper eagle must be sewed to the several threads, and two or more threads may extend from the wings to the centre rod to support the feathers of the wings. the eagle kite appears curious, but is not so elegant as the rose, fig. . to construct this figure there must be four light rods of wood, made to cross each other in the centre, being there lashed together, and thus constituting eight arms. from the end of each arm, a thin strip of light wood or reed, is bent in a curved form to the next arm on either side: the bow being lashed to the arms. this frame is covered with white paper, which is to be afterward colored with rose color, with the yellow centre. the twine must be fastened to four of the arms, and the tail of the kite should be covered with green paper, which by the contrast, will have a pleasing effect. =rochester edge tools in england.= some time since, a mr. ash, an extensive manufacturer of mechanics' tools at sheffield, england, sent to this country for patterns of the latest improvements, and amongst the rest, ordered a variety from messrs. barton & belden of rochester, which were promptly forwarded. on their arrival there, it seems that their make gave such universal satisfaction, that they were immediately copied, and the fact that they came from this country made prominent, by stamping upon them 'rochester pattern.' =an animal curiosity.= travellers state that there is on the island of st. luce a cavern, in which is a large basin twelve or fifteen feet deep, at the bottom of which are rocks. from these rocks proceed certain substances that present at first, sight beautiful flowers, but on the approach of a hand or instrument, retire like a snail, out of sight! on examination, there appears in the middle of a disk, filaments resembling spiders' legs, which moved briskly round a kind of petal. the filaments, or legs, have pincers to seize their prey, when the petals close, so that it cannot escape. under this flower is the body of an animal, and it is probable he lives on the marine insects thrown by the sea into his basin. * * * * * the first clock that ever measured time was made for the caliph of bagdad. this art was afterwards lost for several centuries. =skate runners.= at drontheim, in norway, they have a regiment of soldiers, called skate runners. they wear leg gaiters for travelling in deep snow, and green uniform. they carry a short sword, a rifle fastened by a broad strap passing over the shoulder, and a climbing staff seven feet long, with a spike in the end. they move so fast in the snow that no cavalry can overtake them, and it does little good to fire cannon balls at them, as they go two or three hundred feet apart. they are very useful soldiers in following an enemy on a march. they go over marshes, rivers and lakes at a great rate. =a receipt to make peach wine.= take four or five bushels of ripe juicy peaches, mash or bruise them in a tub, and pour them into a barrel, large enough to contain them, and place it in a cool place. at the bottom of the barrel, before putting in the peaches, some clean straw must be placed to prevent the pumice from filling up the spigot. the head of the barrel must be covered. in about three days the peach wine is ready for use. draw it off, from the spigot, and if care and attention have been adopted, a delicious beverage will be produced. =a novel enterprise.= an expedition, which promises the most important results both to science and commerce is at this moment fitting out in england, for the purpose of navigating some of the more important unexplored rivers in south america it is to be under the command of lord ranelagh. several noblemen and gentlemen have already volunteered to accompany his lordship, and the enterprising and scientific band, it is said, will sail as soon as the necessary arrangements shall be completed. the new york =scientific american:= _published weekly at fulton street., (sun building,) new york._ by munn & company. the scientific american is the advocate of industry and journal of mechanical and other improvements: as such its contents are probably more varied and interesting, than those of any other weekly newspaper in the united states, and certainly more useful. it contains as much interesting intelligence as six ordinary daily papers, while for _real benefit_, it is unequalled by any thing yet published. each number regularly contains from three to six original engravings, illustrated by new inventions, american and foreign,--scientific principles and curiosities,--notices of the progress of mechanical and other scientific improvements, scientific essays on the principles of the sciences of mechanics, chemistry and architecture,--catalogues of american patents,--instruction in various arts and trades, _with engravings_,--curious philosophical experiments,--the latest rail road intelligence in europe and america,--valuable information on the art of gardening, &c. &c. this paper is especially entitled to the patronage of mechanics and manufacturers, being devoted to the interests of those classes. it is particularly useful to farmers, as it will not only apprise them of improvements in agricultural implements, but instruct them in various mechanical trades, and guard against impositions. as a family newspaper, it will convey more useful intelligence to children and young people, than five times its cost in school instruction. being published in quarto form, it is conveniently adapted to preservation and binding. terms.--the scientific american is sent to subscribers in the country at the rate of $ a year, one dollar in advance, the remainder in months. persons desiring to subscribe, have only to enclose the amount in a letter, directed to munn & company, publishers of the scientific american, new york. [illustration: hand pointing right]specimen copies sent when desired. all letters must be post paid.] [illustration] scientific american supplement no. new york, september , . scientific american supplement. vol. xxviii., no. . scientific american established . scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. civil engineering.--the girard hydraulic railway.--one of the great curiosities of the paris exposition, the almost frictionless railway, with sectional illustrations of its structure.-- illustrations. ii. electricity.--early electric lighting.--electric lighting in salem in , a very curious piece of early history. electric motor for alternating currents.--a motor on an entirely new principle for the application of the alternating current with results obtained, and the economic outlook of the invention. portable electric light.--a lamp for military and other use, in which the prime motor, including the boiler and the lamp itself, are carried on one carriage.-- illustration. the electric age.--by charles carleton coffin.--a short _resume_ of the initial achievements of modern electricity. iii. geology.--the fuels of the future.--a prognosis of the future prospect of the world as regards a fuel supply, with a special reference to the use of natural gas. iv. miscellaneous.--preservation of spiders for the cabinet.--a method of setting up spiders for preservation in the cabinet, with formulæ of solutions used and full details of the manipulation.-- illustration. the ship in the new french ballet of the "tempest."--a curious example of modern scenic perfection, giving the construction and use of an appliance of the modern ballet.-- illustrations. v. naval engineering.--crank and screw shafts of the mercantile marine.--by g. w. manuel.--this all-important subject of modern naval engineering treated in detail, illustrating the progress of the present day, the superiority of material and method of using it, with interesting practical examples.-- illustration. experimental aid in the design of high speed steamships.--by d. p.--a plea for the experimental determination of the probable speed of ships, with examples of its application in practice. forging a propeller shaft.--how large steamer shafts are forged, with example of the operation as exhibited to the shah of persia at brown & co.'s works, sheffield, england.-- illustration. the naval forges and steel works at st. chamond.--the forging of a piece of ordnance from a ton ingot of steel, an artistic presentation of the subject.-- illustration. vi. photography.--the pyro developer with metabisulphite of potash.--by dr. j. m. eder.--a new addition to the pyro developer, with formulæ and results. vii. physics.--quartz fibers.--a lecture by mr. c. v. boys on his famous experiments of the production of microscopic fibers, with enlarged illustrations of the same, and a graphic account of the entire subject.-- illustrations. the modern theory of light.--by prof. oliver lodge.--an abstract of a lecture by the eminent investigator and expositor of prof. hertz's experiments, giving a brief review of the present aspect of this absorbing question. viii. physiology.--heat in man.--experiments recently made by dr. loewy on the heat of the human system.--described and commented on by prof. zuntz. ix. sanitation.--on purification of air by ozone--with an account of a new method.--by dr. b. w. richardson.--a very important subject treated in full, giving the past attempts in the utilization of ozone and a method now available. x. technology.--alkali manufactories.--present aspect of the leblanc process and the new process for the recovery of sulphur from its waste. dried wine grapes.--the preparation of the above wine on a large scale in california, with full details of the process adopted. the production of ammonia from coal.--by ludwig mond.--a valuable review of this important industry, with actual working results obtained in carrying out a retort process.-- illustrations. nature, composition, and treatment of animal and vegetable fabrics.--the history of fabrics and fibers in the vegetable and animal world, their sources, applications, and treatments. walnut oil.--by thomas t. p. bruce warren.--an excellent oil for painters' use, with description of a simple method for preparing it on a small scale. * * * * * the naval forges and steel works at st. chamond. with the idyls and historic or picturesque subjects that the universal exposition gives us the occasion to publish, we thought we would make a happy contrast by selecting a subject of a different kind, by presenting to our readers mr. layraud's fine picture, which represents the gigantic power hammer used at the st. chamond forges and steel works in the construction of our naval guns. by the side of the machinery gallery and the eiffel tower this gigantic apparatus is well in its place. [illustration: universal exposition--beaux arts--marine iron and steel works at saint chamond--presentation of a piece of ordnance under the vertical hammer.--picture by m. joseph layraud.] the following is the technical description that has been given to us to accompany our engraving: in an immense hall, measuring ft. in length by ft. in width, a gang of workmen has just taken from the furnace a ton ingot for a large gun for an armor-clad vessel. the piece is carried by a steam crane of tons power, and the men grouped at the maneuvering levers are directing this incandescent mass under the power hammer which is to shape it. this hammer, whose huge dimensions allow it to take in the object treated, is one of the largest in existence. its striking mass is capable of reaching tons, and the height of the fall is ft. to the left of the hammer is seen a workman getting ready to set it in motion. it takes but one man to maneuver this apparatus, and this is one of the characteristic features of its construction. the beginning of this hammer's operation, as well as the operations of the forge itself, which contains three other hammers of less power, dates back to . it is with this great hammer that the largest cannons of the naval artillery--those of inches--have been made (almost all of which have been manufactured at st. chamond), and those, too, of , , and inches. this is the hammer, too, that, a few months ago, was the first to be set at work on the huge in. guns of new model, whose length is no less than ft. in the rough. let us add a few more figures to this account in order to emphasize the importance of the installations which mr. layraud's picture recalls, and which our great french industry has not hesitated to establish, notwithstanding the great outlay that they necessitated. this huge hammer required foundations extending to a depth of ft., and the amount of metal used in its construction was , , pounds. the cost of establishing the works with all the apparatus contained therein was $ , .--_le monde illustré._ * * * * * forging a propeller shaft. during the recent visit of the shah of persia to england, he visited, among other places, the great works of john brown & co., at sheffield, and witnessed the pressing of a propeller shaft for one of the large ocean steamships. the operation is admirably illustrated in our engraving, for which we are indebted to the _illustrated london news_. [illustration: propeller shaft being pressed at messrs. john brown & co.'s works, sheffield.] * * * * * crank and screw shafts of the mercantile marine.[ ] by g. w. manuel. [footnote : a paper read before the institute of marine engineers, stratford, .] being asked to read a paper before your institute, i have chosen this subject, as i think no part of the marine engine has given so much trouble and anxiety to the seagoing engineer; and from the list of shipping casualties in the daily papers, a large proportion seem due to the shafting, causing loss to the shipowner, and in some instances danger to the crew. my endeavor is to put some of the causes of these casualties before you, also some of the remedies that have tended to reduce their number. several papers have been read on this subject, chiefly of a theoretical description, dealing with the calculations relating to the twisting and bending moments, effects of the angles of the cranks, and length of stroke--notably that read by mr. milton before the institute of naval architects in . the only _practical_ part of this paper dealt with the possibility of the shafts getting out of line; and regarding this contingency dr. kirk said that "if superintendent engineers would only see that the bearings were kept in line, broken crank and other shafts would not be so much heard of." of course this is one of those statements made in discussions of this kind, for what purpose i fail to see, and as far as my own experience goes is _misleading_; for having taken charge of steamers new from the builders' hands, when it is at least expected that these shafts would _be in line_, the crank shaft bearings heated very considerably, and _continued_ to do so, rendering the duration of life of the crank shaft a short one; and though they were never what is termed out of line, the bearings could _not_ be kept cool without the use of sea water, and occasionally the engines had to be stopped to cool and smooth up the bearing surfaces, causing delays, worry, and anxiety, for which the engineer in charge was in no way responsible. happily this state of what i might call _uncertainties_ is being gradually remedied, thanks being largely due to those engineers who have the skill to suggest improvements and the patience to carry them out against much opposition. these improvements in many instances pertain to the engine builder's duties, and are questions which i think have been treated lightly; notably that of insufficient bearing surface, and one of the principal causes of hot bearings, whereby the oil intended for lubrication was squeezed out, and the metal surfaces brought too close in contact; and when bearings had a pressure of lb. per square inch, it has been found that not more than lb. per square inch should be exerted to keep them cool (this varies according to the material of which the bearing is composed), without having to use sea water and prevent them being ground down, and thus getting out of line. i have known a bearing in a new steamer, in spite of many gallons of oil wasted on it, wear down one-eighth of an inch in a voyage of only , miles, from insufficiency of bearing surface. several good rules are in use governing the strength of shafts, which treat of the diameter of the bearings only and angles of the cranks; and the engine builder, along with the ship owner, has been chary of increasing the surfaces by lengthening the bearings; for to do this means increase of space taken up fore and aft the vessel, besides additional weight of engine. engine builders all aim in competing to put their engines in less space than their rivals, giving same power and sometimes more. i think, however, this inducement is now more carefully considered, as it has been found more economical to give larger bearing surfaces than to have steamers lying in port, refitting a crank shaft, along with the consequences of heavy bills for salvage and repairs, also the risk of losing the steamer altogether. proportioning the bearings to the weights and strains they have to carry has also been an improvement. the different bearings of marine engines were usually made alike in surface, irrespective of the work each had to do, with a view to economy in construction. in modern practice the after bearings have more surface than the forward, except in cases where heavy slide-valve gear has to be supported, so that the wear down in the whole length of the shaft is equal, thus avoiding those alternate bending strains at the top and bottom of the stroke every revolution. another improvement that has been successfully introduced, adding to the duration of life of crank shafts, is the use of white bearing metal, such as parson's white brass, on which the shafts run smoothly with less friction and tendency to heat, so that, along with well proportioned surfaces, a number of crank shafts in the peninsular and oriental co.'s service have not required lining up for eight years, and i hope with care may last till new boilers are required. large and powerful steamers can be driven full speed from london to australia and back without having any water on the bearings, using oil of only what is considered a moderate price, allowing the engineer in charge to attend to the economical working of both engines and boilers (as well as many other engines of all kinds now placed on board a large mail and passenger steamer), instead of getting many a drenching with sea water, and worried by close attention to one or two hot bearings all the watch. compare these results with the following: in the same service in , and with no blame to the engineer in charge, the crank shaft bearings of a screw steamer had to be lined up every five days at intermediate ports, through insufficient bearing surfaces. sea water had continually to be used, resulting in frequent renewal of crank shaft. steamers can now run , miles without having to lift a bearing, except for examination at the end of the voyage. i would note here that the form of the bearings on which the shafts work has also been much improved. they are made more of a _solid character_, the metal being more equally disposed _round_ the shaft, and the use of gun metal for the main bearings is now fast disappearing. in large engines the only metals used are cast iron and white brass, an advantage also in reducing the amount of wear on the recess by corrosion and grinding where sea water was used often to a considerable extent. [illustration: fig. fig. ] figs. no. and no. show the design of the old and new main bearings, and, i think, require but little explanation. most of you present will remember your feelings when, after a hot bearing, the brasses were found to be cracked at top and bottom, and the trouble you had afterward to keep these brasses in position. when a smoking hot bearing occurred, say in the heating of a crank pin, it had the effect of damaging the material of the shaft more or less, according to its original soundness, generally at the fillets in the angles of the cranks. for when the outer surface of the iron got hot, cold water, often of a low temperature, was suddenly poured on, and the hot iron, previously expanded, was suddenly contracted, setting up strains which in my opinion made a small tear transversely where the metal was _solid_; and where what is termed lamination flaws, due to construction, existed, these were extended in their natural direction, and by a repetition of this treatment these flaws became of such a serious character that the shafts had to be condemned, or actually gave way at sea. the introduction of the triple expansion engine, with the three cranks, gave better balance to the shaft, and the forces acting in the path of the crank pin, being better divided, caused more regular motion on the shaft, and so to the propeller. this is specially noticeable in screw steamers, and is taken advantage of by placing the cabins further aft, nearer the propeller, the stern having but little vibration; the dull and heavy surging sound, due to unequal motions of the shaft in the two-crank engines, is exchanged for a more regular sound of less extent, and the power formerly wasted in vibrating the stern is utilized in propelling the vessel. in spite of all these improvements i have mentioned, there remains the serious question of defects in the material, due to variety of quality and the extreme care that has to be exercised in all the stages during construction of crank or other shafts built of iron. many shafts have given out at sea and been condemned, through no other cause than _original defects_ in their construction and material. the process of welding and forging a crank shaft of large diameter now is to make it up of so many small _pieces_, the _best shafts_ being made of what is termed scrap, representing thousands of small pieces of selected iron, such as cuttings of old iron boiler plates, cuttings off forgings, old bolts, horseshoes, angle iron, etc., all welded together, forged into billets, reheated, and rolled into bars. it is then cut into lengths, piled, and formed into slabs of suitable size for welding up into the shafts. no doubt this method is preferable to the old method of "fagoting," so called, as the iron bars were placed side by side, resembling a bundle of fagots of about or inches square. the result was that while the outside bars would be welded, the inside would be improperly welded, or, the hammer being weak, the blow would be insufficient to secure the proper weld, and it was no uncommon thing for a shaft to break and expose the internal bars, showing them to be quite separate, or only partially united. this danger has been much lessened in late years by careful selection of the materials, improved methods of cleaning the scrap, better furnaces, the use of the most suitable fuels, and more powerful steam hammers. still, with all this care, i think i may say there is not a shaft without flaws or defects, more or less, and when these flaws are situated in line of the greatest strains, and though you _may not_ have a hot bearing, they often extend until the shaft becomes unseaworthy. [diagrams shown illustrated the various forms of flaws.] these flaws were not observable when the shafts were new, although carefully inspected. they gradually increased under strain, came to the outside, and were detected. considerable loss fell upon the owners of these vessels, who were in no way to blame; nor could they recover any money from the makers of the shafts, who were alone to blame. i am pleased to state, and some of the members here present know, that considerable improvement has been effected in the use of better material than iron for crank shafts, by the introduction of a special mild steel, by messrs. vickers, sons & co., of sheffield, and that instead of having to record the old familiar defects found in iron shafts, i can safely say no flaws have been observed, when new or during eight years running, and there are now twenty-two shafts of this mild steel in the company's service. i may here state that steel was used for crank shafts in this service in , as then manufactured in prussia by messrs. krupp, and generally known as _krupp's steel_, the tensile strength of which was about tons per square inch, and though free from flaws, it was unable to stand the fatigue, and broke, giving little warning. it was of too brittle a nature, more resembling chisel steel. it was broken again under a falling weight of cwt. with a ft. drop = ½ tons. the mild steel now used was first tried in . it possessed tensile strength of to tons per square inch. it was then considered advisable not to exceed this, and err rather on the safe side. this shaft has been in use eight years, and no sign of any flaw has been observed. since then the tensile strength of mild steel has gradually been increased by messrs. vickers, the steel still retaining the elasticity and toughness to endure fatigue. this has only been arrived at by improvements in the manufacture and more powerful and better adapted hammers to forge it down from the large ingots to the size required. the amount of work they are now able to subject the steel to renders it more fit to sustain the fatigue such as that to be endured by a crank shaft. these ingots of steel can be cast up to tons weight, and require powerful machines to deal with them. for shafts say of inches diameter, the diameter of the ingot would be about inches. this allows sufficient work to be put on the couplings, as well as the shaft. to make solid crank shafts of this material, say of inches diameter, the ingot would weigh tons, the forging, when completed, tons, and the finished shaft ¾ tons; so that you see there is tons wasted before any machining is done, and ¼ tons between the forging and finished shaft. this makes it very expensive for solid shafts of large size, and it is found better to make what is termed a _built shaft_; the cranks are a little heavier, and engine framings necessarily a little wider, a matter comparatively of little moment. i give you a rough drawing of the hydraulic hammer, or strictly speaking a _press_, used by messrs. vickers in forging down the ingots in shafts, guns, or other large work. this hammer can give a squeeze of , tons. the steel seems to yield under it like tough putty, and, unlike the steam hammer, there is no _jarring_ on the material, and it is manipulated with the same ease as a small hammer by hydraulics. the tensile strength of steel used for shafts having increased from to tons, and in some cases tons, considering that this was tons above that specified, and that we were approaching what may be termed _hard steel_, i proposed to the makers to test this material beyond the usual tests, viz., tensile, extension, and cold bending test. the latter, i considered, was much too easy for this fine material, as a piece of fair iron will bend cold to a radius of ½ times its diameter or thickness, without fracture; and i proposed a test more resembling the fatigue that a crank shaft has sometimes to stand, and more worthy of this material; and in the event of its standing this successfully, i would pass the material of or tons tensile strength. specimens of steel used in the shafts were cut off different parts--crank pins and main bearings--(the shafts being built shafts) and roughly planed to ½ inches square, and about inches long. they were laid on the block as shown, and a cast iron block, fitted with a hammer head ½ ton weight, let suddenly fall inches, the block striking the bar with a blow of about tons. the steel bar was then turned upside down, and the blow repeated, reversing the piece every time until fracture was observed, and the bar ultimately broken. the results were that this steel stood blows before showing signs of fracture, and was only broken after blows. it is noticeable how many blows it stood after fracture. a bar of good wrought iron, undressed, of same dimensions, was tried, and broke the first blow. a bar cut from a piece of iron to form a large chain, afterward forged down and only filed to same dimensions, broke at blows. i was well satisfied with the results, and considered this material, though possessing a high tensile strength, was in every way suitable for the construction and endurance required in crank shafts. sheet no. shows you some particulars of these tests: tensile elong. fractured broke fall tons. in " bend. blows. blows. in. a = . p. c. good in order to test the comparative value of steel of ¾ up to tons tensile strength, i had several specimens taken from shafts tested in the manner described, which may be called a _fatigue_ test. the results are shown on the same sheet: b = ½ good b -- -- -- c = . p. c. good d = . . p. c. good e = . . p. c. good f = . p. c. good the latter was very tough to break. specimen marked a shows one of these pieces of steel. i show you also fresh broken specimens which will give you a good idea of the beautiful quality of this material. these specimens were cut out of shafts made of steel co. of scotland's steel. i also show you specimens of cold bending: tensile elong. fractured broke fall tons. in. " bend. blows. blows. in. g = . ½ p. c. good h = . p. c. good i = . . p. c. good i think all of the above tests show that this material, when carefully made and treated with sufficient mechanical work on forging down from the ingot, is suitable up to tons for crank shafts; how much higher it would be desirable to go is a question of superior excellence in material and manufacture resting with the makers. i would, however, remark that no allowance has been made by the board of trade or lloyds for the excellence of this material above that of iron. i was interested to know how the material in the best iron shafts would stand this fatigue test compared with steel, and had some specimens of same dimensions cut out of iron shafts. the following are the results: best iron, three good qualities, rolled into flat bars, cut and made into ½ cwt. blooms. j = . . p. c. good made of best double rolled scrap, ½ cwt. blooms. k = ½ p. c. good you will see from these results that steel stood this fatigue test, vickers' per cent. and steel co.'s per cent., better than iron of the best quality for crank shafts; and i am of opinion that so long as we use such material as these for crank shafts, along with the present rules, and give ample _bearing surface_, there will be few broken shafts to record. i omitted to mention that built shafts, both of steel and iron, of large diameter, are now in general use, and with the excellent machines, and under special mechanics, are built up of five separate pieces in such a rigid manner that they possess all the solidity necessary for a crank shaft. the forgings of iron and steel being much smaller are capable of more careful treatment in the process of manufacture. these shafts, for large mail steamers, when coupled up, are feet long, and weigh tons. they require to be carefully coupled, some makers finishing the bearings in the lathe, others depend on the excellence of their work in each piece, and finish each complete. to insure the correct centering of these large shafts, i have had in. dia. recesses ¾ inch deep turned out of each coupling to one gauge and made to fit one disk. duplicate disks are then fitted in each coupling, and the centering is preserved, and should a spare piece be ever required, there is no trouble to couple correctly on board the steamer. the propeller shaft is generally made of iron, and if made _not less_ than the board of trade rules as regards diameter, of the best iron, and the gun metal liners carefully fitted, they have given little trouble; the principal trouble has arisen from defective fitting of the propeller boss. this shaft working in sea water, though running in lignum vitæ bearings, has a considerable wear down at the outer bearings in four or five years, and the shaft gets out of line. this wear has been lessened considerably by fitting the wood so that the grain is endway to the shaft, and with sufficient bearing surface these bearings have not required lining up for nine years. it is, however, a shaft that cannot be inspected except when in dry dock, and has to be disconnected from the propeller, and drawn inside for examination at periods suggested by experience. serious accidents have occurred through want of attention to the examination of this shaft; when working in salt water, with liners of gun metal, galvanic action ensues, and extensive corrosion takes place in the iron at the ends of the brass liners, more especially if they are faced up at right angles to the shaft. some engineers have the uncovered part of the shaft between the liners, inside the tube, protected against the sea water by winding over it tarred line. as this may give out and cause some trouble, by stopping the water space, i have not adopted it, and shall be pleased to have the experience of any seagoing engineer on this important matter. a groove round the shaft is formed, due to this action, and in some cases the shaft has broken inside the stern tube, breaking not only it, but tearing open the hull, resulting in the foundering of the vessel. steel has been used for screw shafts, but has not been found so suitable, as it corrodes more rapidly in the presence of salt water and gun metal than iron, and unless protected by a solid liner for the most part of its length, a mechanical feat which has not yet been achieved in ordinary construction, as this liner would require to be ft. long. i find it exceedingly difficult to get a liner of only ft. long in one piece, and the majority of ft. liners are fitted _in two pieces_. the joint of the two liners is rarely _watertight_, and many shafts have been destroyed by this method of fitting these liners. i trust that engine builders will make a step further in the fitting of these liners on these shafts, as it is against the interest of the _shipowner_ to keep ships in dry dock from such causes as defective liners, and i think it will be only a matter of time when the screw shaft will be completely protected from sea water, at least inside the stern tube; and when this is done, i would have no hesitation in using steel for screw shafts. though an easier forging than a crank shaft, these shafts are often liable to flaws of a very serious character, owing to the contraction of the _mass_ of metal forming the coupling; the outside cooling first tears the center open, and when there is not much metal to turn off the face of the coupling, it is sometimes undiscovered. having observed several of these cavities, some only when the _last cut_ was being taken off, i have considered it advisable to have holes bored in the end and center of each coupling, as far through as the thickness of the flange; when the shafts are of large size, this is sure to find these flaws out. another flaw, which has in many cases proved serious when allowed to extend, is situated immediately abaft the gun metal liner, in front of the propeller. this may be induced by corrosion, caused by the presence of sea water, gun metal, and iron, assisted by the rotation of the shaft. it may also be caused under heavy strain, owing to the over-finishing of the shaft at this part under the steam hammer. the forgemen, in these days of competition and low prices, are instructed to so finish that there won't be much weight to turn off when completing the shaft in the lathe. this is effected by the use of half-round blocks under the hammer, at a lower temperature than the rest of the forging is done, along with the use of a little water flung on from time to time; and it is remarkable how near a forging is in truth when centered in the lathe, and how little there is to come off. the effect of this manipulation is to form a hard ring of close grain about one inch thick from the circumference of the shaft inward. the metal in this ring is much harder than that in the rest of the shaft, and takes all the strain the inner section gives; consequently, when strain is brought on, either in heavy weather or should the propeller strike any object at sea or in the suez canal, a fracture is caused at the circumference. this, assisted by slight corrosion, has in my experience led in the course of four months to a screw shaft being seriously crippled. i show you a section of a screw shaft found to be flawed, and which i had broken under the falling weight of a steam hammer, when the decided difference of the granules near the circumference from that in the central part conveyed to me that it was weakened by treatment i have referred to. i think more material should be left on the forging, and the high finish with a little cold water should be discontinued. doing away with the outer bearing in rudder post is an improvement, provided the bearing in the outer end of screw shaft in the stern tube is sufficiently large. it allows the rudder post to have its own work to do without bringing any strain on the screw shaft, and in the event of the vessel's grounding and striking under the rudder post, it does not throw any strain on the screw shaft. it also tends to reduce weight at this part, where all the weight is overhung from the stern of the vessel. * * * * * experimental aid in the design of high speed steamships. by d. p. the achievement of one triumph after another in the matter of high speed steamships, and especially the confidence with which pledges of certain results are given and accepted long before actual trials are made, form one of the most convincing proofs of the important part which scientific methods play in modern shipbuilding. this is evident in the case of ships embodying novel or hitherto untried features, and more especially so in cases where shipbuilders, having no personal practical experience or data, achieve such results. this was notably illustrated in the case of the fairfield co. undertaking some five years ago to build and engine a huge craft of most phenomenal form and proportions, and to propel the vessel at a given speed under conditions which appeared highly impracticable to many engaged in the same profession. the contract was proceeded with, however, and the czar of russia's wonderful yacht livadia was the result, which (however much she may have justified the professional strictures as to form and proportions) entirely answered the designer's anticipations as to speed. equally remarkable and far more interesting instances are the inman liners city of paris and city of new york, in whose design there was sufficient novelty to warrant the degree of misgiving which undoubtedly existed regarding the messrs. thomson's ability to attain the speed required. in the case at least of the city of paris, messrs. thomson's intrepidity has been triumphantly justified. an instance still more opposite to our present subject is found in the now renowned channel steamers princess henrietta and princess josephine, built by messrs. denny, of dumbarton, for the belgian government. the speed stipulated for in this case was ½ knots, and although in one or two previous channel steamers, built by the fairfield co., a like speed had been achieved, still the guaranteeing of this speed by messrs. denny was remarkable, in so far as the firm had never produced, or had to do with, any craft faster than or knots. the attainment not only of the speed guaranteed, but of the better part of a knot in excess of that speed, was triumphant testimony to the skill and care brought to bear upon the undertaking. in this case, at least, the result was not one due to a previous course of "trial and error" with actual ships, but was distinctly due to superior practical skill, backed and enhanced by knowledge and use of specialized branches in the science of marine architecture. messrs. denny are the only firm of private shipbuilders possessing an experimental tank for recording the speed and resistance of ships by means of miniature reproductions of the actual vessels, and to this fact may safely be ascribed their confidence in guaranteeing, and their success in obtaining, a speed so remarkable in itself and so much in excess of anything they had previously had to do with. confirmatory evidence of their success with the belgian steamers is afforded by the fact that they have recently been instructed to build for service between stranraer and larne a paddle steamer guaranteed to steam knots, and have had inquiries as to other high speed vessels. in estimating the power required for vessels of unusual types or of abnormal speed, where empirical formulæ do not apply, and where data for previous ships are not available, the system of experimenting with models is the only trustworthy expedient. in the case of the czar's extraordinary yacht, the livadia, already referred to, it may be remembered that previous to the work of construction being proceeded with, experiments were made with a small model of the vessel by the late dr. tideman, at the government tank at amsterdam. on the strength of the data so obtained, coupled with the results of trials made with a miniature of the actual vessel on loch lomond, those responsible for her stipulated speed were satisfied that it could be attained. the actual results amply justified the reliance placed upon such experiments. the design of many of her majesty's ships has been altered after trials with their models. this was notably the case in connection with the design of the medway class of river gunboats. the admiralty constructors at first determined to make them ft. long, by only ft. in breadth. a doubt arising in their minds, the matter was referred to the late mr. froude, who had models made of various breadths, with which he experimented. the results satisfied the admiralty officers that a substantial gain, rather than a loss, would follow from giving them much greater beam than had been proposed, and this was amply verified in the actual ships. so long ago as the last decade of last century, an extended series of experiments with variously shaped bodies, ships as well as other shapes, were conducted by colonel beaufoy, in greenland dock, london, under the auspices of a society instituted to improve naval architecture at that time. robert fulton, of america, david napier, of glasgow, and other pioneers of the steamship, are related to have carried out systematic model experiments, although of a rude kind in modern eyes, before entering on some of their ventures. about mr. john scott russell carried on, on behalf of the british association, of which he was at that time one of its most distinguished members, an elaborate series of investigations into the form of least resistance in vessels. for this purpose he leased the virginia house and grounds, a former residence of rodger stewart, a famous greenock shipowner of the early part of the century, the house being used as offices, while in the grounds an experimental tank was erected. in it tests were made of the speed and resistance of the various forms which mr. russell's ingenuity evolved--notably those based on the well-known stream line theory--as possible types of the steam fleets of the future. all the data derived from experiment was tabulated, or shown graphically in the form of diagrams, which, doubtless, proved of great interest to the _savants_ of the british association of that day. mr. russell returned to london in , and the investigations were discontinued. it will thus be seen that model experiments had been made by investigators long before the time of the late dr. william froude, of torquay. it was not, however, until this gentleman took the subject of resistance of vessels in hand that designers were enabled to render the results from model trials accurately applicable to vessels of full size. this was principally due to his enunciation and verification by experiment of what is now known as the "law of comparison," or the law by which one is enabled to refer accurately the resistance of a model to one of larger size, or to that of a full sized vessel. in effect, the law is this--for vessels of the same proportional dimensions, or, as designers say, of the same lines, there are speeds appropriate to these vessels, which vary as the square roots of the ratio of their dimensions, and at these appropriate speeds the resistances will vary as the cubes of these dimensions. the fundament upon which the law is based has recently been shown to have found expression in the works of f. reech, a distinguished french scientist who wrote early in the century. there are no valid grounds for supposing that the discovery of reech was familiar to froude; but even were this so, it is abundantly evident that, although never claimed by himself, there are the best of grounds for claiming the law of comparison, as now established, to be an independent discovery of froude's. dr. froude began his investigations with ships' models at the experimental tank at torquay about , carrying it on uninterruptedly until his death in . since his decease, the work of investigation has been carried on by his son, mr. r. e. froude, who ably assisted his father, and originated much of the existing apparatus. at the beginning of , the whole experimental appliances and effects were removed from torquay to haslar, near portsmouth, where a large tank and more commodious offices have been constructed, with a view to entering more extensively upon the work of experimental investigation. the dimensions of the old tank were ft. in length, ft. in width, and ft. in depth. the new one is about ft. long, ft. wide, and ft. deep. the new establishment is more commodious and better equipped than the old, and although the experiments are taken over a greater length, the operators are enabled to turn out results with as great dispatch as in the torquay tank. the adjacency of the new tank to the dockyard at portsmouth enables the admiralty authorities to make fuller and more frequent use of it than formerly. since the value of the work carried on for the british government has become appreciated, several experimental establishments of a similar character have been instituted in other countries. the dutch government in formed one at amsterdam which, up till his death in , was under the superintendence of dr. tideman, whose labors in this direction were second only to those of the late dr. froude. in the french naval authorities established an experimental tank in the dockyard at brest, and the italian government have just completed one on an elaborate scale in the naval dockyard at spezia. the spezia tank, which is ft. in length by about ft. in breadth, is fully equipped with all the special and highly ingenious instruments and appliances which the scientific skill of the late dr. froude brought into existence, and have been since his day improved upon by his son, mr. r. e. froude, and other experts. through the courtesy of our own admiralty and of messrs. denny, of dumbarton, the italians have been permitted to avail themselves of the latest improvements which experience has suggested, and the construction of the special machinery and apparatus required has been executed by firms in this country having previous experience in this connection--messrs. kelso & co., of commerce street, glasgow; and mr. robert w. munro, of london. having briefly traced the origin and development of the system of model experiment, it may now be of interest to describe the _modus operandi_ of such experiments, and explain the way in which they are made applicable to actual ships. the models with which experiments are made in those establishments conducted on the lines instituted by mr. froude are made of paraffin wax, a material well adapted for the purpose, being easily worked, impervious to water, and yielding a fine smooth surface. moreover, when done with, the models may be remelted for further use and all parings utilized. they are produced in the following manner: a mould is formed in clay by means of cross sections made somewhat larger than is actually required, this allowance being made to admit of the cutting and paring afterward required to bring the model to the correct point. into this mould a core is placed, consisting of a light wooden framework covered with calico and coated with a thick solution of clay to make it impervious to the melted paraffin. this latter substance is run into the space between the core and the mould and allowed to cool. this space, forming the thickness of the model, is usually from ¾ in. for a model of ft. long to ¼ in. and ½ in. for one of ft. and ft. long. when cold, the model is floated out of the mould by water pressure and placed bottom upward on the bed of a shaping machine, an ingenious piece of mechanism devised by the late dr. froude, to aid in reducing the rough casting to the accurate form. the bed of this machine, which travels automatically while the machine is in operation, can be raised or lowered to any desired level by adjusting screws. a plan of water lines of the vessel to be modeled is placed on a tablet geared to the machine, the travel of which is a function of the travel of the bed containing the model. with a pointer, which is connected by a system of levers to the cutting tools, the operator traces out the water lines upon the plan as the machine and its bed are in motion, with the result that corresponding lines are cut upon the model. the cutting tools are swiftly revolving knives which work on vertical spindles moved in a lateral direction (brought near or removed from each other), according to the varying breadth of the water lines throughout the length of the model, as traced out by the operator's pointer. in this way a series of longitudinal incisions are made on the model at different levels corresponding to the water lines of the vessel. the model is now taken from the bed of the machine and the superfluous material or projection between the incisions is removed by means of a spokeshave or other sharp hand tool, and the whole surface brought to the correct form, and made fair and smooth. to test accuracy of form, the weight of model is carefully taken, and the displacement at the intended trial draught accurately determined from the plan of lines. the difference between the weight of model and the displacement at the draught intended is then put into the bottom of the model in the form of small bags of shot, and by unique and very delicately constructed instruments for ascertaining the correct draught, the smallest error can at once be detected and allowed for. the models vary in size from about one-tenth to one-thirtieth of the size of the actual ship. a model of the largest size can be produced and its resistance determined at a number of speeds in about two days or so. the mode of procedure in arranging the model for the resistance experiment, after the model is afloat in the tank at the correct draught and trim, consists in attaching to it a skillfully devised dynamometric apparatus secured to a lightly constructed carriage. this carriage traverses a railway which extends the whole length of the tank about in. or in. above the water. the floating model is carefully guided in its passage through the water by a delicate device, keeping it from deviating either to the right or left, but at the same time allowing a free vertical and horizontal motion. the carriage with the model attached is propelled by means of an endless steel wire rope, passing at each end of the tank around a drum, driven by a small stationary engine, fitted with a very sensitive governor, capable of being so adjusted that any required speed may be given to the carriage and model. the resistance which the model encounters in its passage through the water is communicated to a spiral spring, and the extension this spring undergoes is a measure of the model's resistance. the amount of the extension is recorded on a revolving cylinder to a much enlarged scale through the medium of levers or bell cranks supported by steel knife edges resting on rocking pieces. on the same cylinder are registered "time" and "distance" diagrams, by means of which a correct measure of the speed is obtained. the time diagram is recorded by means of a clock attached to an electric circuit, making contact every half second, and actuating a pen which forms an indent in what would otherwise be a straight line on the paper. the distance pen, by a similar arrangement, traces another line on the cylinder in which are indents corresponding to fixed distances of travel along the tank, the indents being caused by small projections which strike a trigger at the bottom of the carriage as it passes, and make electric contact. from these time and distance diagrams accurate account can be taken of the speed at which the model and its supporting carriage have been driven. thus on the same cylinder is recorded graphically the speed and resistance of the model. the carriage may be driven at any assigned speed by adjusting the governor of the driving engine already alluded to, but the record of the speed by means of the time and distance diagrams is more definite. when the resistances of the model have been obtained at several speeds, varying in some cases from to , feet per minute, the speeds are set off in suitable units along a base line, and for every speed at which resistance is measured, the resistance is set off to scale as an ordinate value at those speeds. a line passing through these spots forms the "curve of resistance," from which the resistance experienced by the model at the given trial speeds or any intermediate speed can be ascertained. the resistance being known, the power required to overcome resistance and drive the actual ship at any given speed is easily deduced by applying the rule before described as the law of comparison.--_the steamship._ * * * * * the ship in the new french ballet of the "tempest." a new ballet, entitled the "tempest," by messrs. barbier and thomas, has recently been put upon the stage of the opera at paris with superb settings. one of the most important of the several tableaux exhibited is the last one of the third act, in which appears a vessel of unusual dimensions for the stage, and which leaves far behind it the celebrated ships of the "corsaire" and "l'africaine." this vessel, starting from the back of the stage, advances majestically, describes a wide circle, and stops in front of the prompter's box. [illustration: fig. .--ship of the "tempest," in process of construction.] [illustration: fig. .--setting of the scenery before and after the appearance of the ship.] as the structure of this vessel and the mechanism by which it is moved are a little out of the ordinary, we shall give some details in regard to them. first, the sea is represented by four parallel strips of water, each formed of a vertical wooden frame entirely free in its movements (fig. ). the ship (figs. , , , and ) is carried by wheels that roll over the floor of the stage. it is guided in its motion by two grooved bronze wheels and by a rail formed of a simple reversed t-iron which is fixed to the floor by bolts. in measure as it advances, the strips of water open in the center to allow it to pass, and, as the vessel itself is covered up to the water line with painted canvas imitating the sea, it has the appearance of cleaving the waves. as soon as it has passed, the three strips of water in the rear rise slightly. when the vessel reaches the first of the strips, the three other strips, at first juxtaposed against the preceding, spread out and thus increase the extent of the sea, while the inclined plane of the preceding tableau advances in order to make place for the vessel. the shifting of this inclined place is effected by simply pulling upon the carpet that covers it, and which enters a groove in the floor in front of the prompter's box. at this moment, the entire stage seems to be in motion, and the effect is very striking. [illustration: fig. .--ship of the new ballet, the "tempest."] we come now to the details of construction of the vessel. it is not here a question of a ship represented simply by means of frames and accessories, but of a true ship in its entirety, performing its evolutions over the whole stage. now, a ship is not constructed at a theater as in reality. it does not suffice to have it all entire upon the stage, but it is necessary also to be able to dismount it after every representation, and that, too, in a large number of pieces that can be easily stored away. thus, the vessel of the tempest, which measures a dozen yards from stem to stern, and is capable of carrying fifty persons, comes apart in about pieces of wood, without counting all the iron work, bolts, etc. nevertheless, it can be mounted in less than two hours by ten skilled men. [illustration: fig. .--the ship with its occupants.] the visible hull of the ship is placed upon a large and very strong wooden framework, formed of twenty-six trusses. in the center, there are two longitudinal trusses about three feet in height by twenty-five in length, upon which are assembled, perpendicularly, seven other trusses. in the interior there are six transverse pieces held by stirrup bolts, and at the extremity of each of these is fixed a thirteen-inch iron wheel. it is upon these twelve wheels that the entire structure rolls. there are in addition the two bronze guide wheels that we have already spoken of. in the rear there are two large vertical trusses sixteen feet in height, which are joined by ties and descend to the bottom of the frame, to which they are bolted. these are worked out into steps and constitute the skeleton of the immense stern of the vessel. the skeleton of the prow is formed of a large vertical truss which is bolted to the front of the frame and is held within by a tie bar. on each side of this truss are placed the _parallels_ (figs. and ), which are formed of pieces of wood that are set into the frame below and are provided above with grooves for the passage of iron rods that support the foot rests by means of which the supernumeraries are lifted. as a whole, those rods constitute a jointed parallelogram, so that the foot rest always remains horizontal while describing a curve of five feet radius from the top of the frame to the deck of the vessel. they are actuated by a cable which winds around a small windlass fixed in the interior of the frame. [illustration: fig. .--the ship as seen from the stage.] the large mast consists of a vertical sheath ft. high, which is set into the center of the frame, and in the interior of which slides a wooden spar that exceeds it by ft. at first, and is capable of being drawn out as many more feet for the final apotheosis. this part of the mast carries three footboards and a platform for the reception of "supers." it is actuated by a windlass placed upon the frame. to form the skeleton of the vessel there are mounted upon the frame a series of eight large vertical trusses parallel with each other and cross-braced by small trusses. the upper part of these supports the flooring of the deck, and their exterior portion affects the curve of a ship's sides. it is to these trusses that are attached the panels covered with painted canvas that represent the hull. these panels are nine in number on each side. above are placed those that simulate the nettings and those that cover the prow or form its crest. the turret that surrounds the large mast is formed of vertical trusses provided with panels of painted canvas and carrying a floor for the figurants to stand upon. the bowsprit is in two parts, one sliding in the other. the front portion is at first pulled back, in order to hide the vessel entirely in the side scenes. it begins to make its appearance before the vessel itself gets under way. light silken cordages connect the mast, the bowsprit, and the small mast at the stern. on each side of the vessel, there are bolted to the frame that supports it five iron frames covered with canvas (fig. ), which reach the level of the water line, and upon which stand the "supers" representing the naiads that are supposed to draw the ship upon the beach. finally at the bow there is fixed a frame which supports a danseuse representing the living prow of the vessel. the vessel is drawn to the middle of the stage by a cable attached to its right side and passing around a windlass placed in the side scenes to the left (fig. ). it is at the same time pushed by machinists placed in the interior of the framework. the latter, as above stated, is entirely covered with painted canvas resembling water. as the vessel, freighted with harmoniously grouped spirits, and with naiads, sea fairies, and graceful genii seeming to swim around it, sails in upon the stage, puts about, and advances as if carried along by the waves to the front of the stage, the effect is really beautiful, and does great credit to the machinists of the opera. we are indebted to _le genie civil_ and _le monde illustré_ for the description and engravings. * * * * * the girard hydraulic railway. [illustration: fig. .] [illustration: fig. .] we give herewith some illustrations of this railway which has recently excited so much technical interest in europe and america, and which threatens to revolutionize both the method and velocity of traveling, if only the initial expense of laying the line can be brought within moderate limits. a short line of railway has been laid in paris, and we have there examined it, and traveled over the line more than once; so that we can testify to the smoothness and ease of the motion. sir edward watkin examined the railway recently, and we understand that a line two miles long is to be laid in london, under his auspices. he seems to think it might be used for the channel tunnel, being both smokeless and noiseless. it might also, if it could be laid at a sufficiently low price, be useful for the underground railways in london, of one of which he is chairman. we are favorably impressed by the experiments we have witnessed; our misgivings are as to the cost. the railway is the invention of the well known hydraulic engineer, monsieur girard, who, as early as , endeavored to replace the ordinary steam traction on railways by hydraulic propulsion, and in sought to diminish the resistance to the movement of the wagons by removing the wheels, and causing them to slide on broad rails. in order to test the invention, mons. girard demanded, and at the end of obtained, a concession for a short line from paris to argenteuil, starting in front of the palais de l'industrie, passing by le champ de courses de longchamps, and crossing the seine at suresnes. unfortunately, the war of - intervened, during which the works were destroyed and mons. girard was killed. after his death the invention was neglected for some years. a short time ago, however, one of his former colleagues, mons. barre, purchased the plans and drawings of mons. girard from his family, and having developed the invention, and taken out new patents, formed a company to work them. the invention may be divided into two parts, which are distinct, the first relating to the mode of supporting the carriages and the second to their propulsion. each carriage is carried by four or six shoes, shown in figs. , , and ; and these shoes slide on a broad, flat rail, in. or in. wide. the rail and shoe are shown in section in fig. . the rail is bolted to longitudinal wooden sleepers, and the shoe is held on the rail by four pieces of metal, a, two on each side, which project slightly below the top of the rail. the bottom of the shoe which is in contact with the rail is grooved or channeled, so as to hold the water and keep a film between each shoe and the rail. the carriage is supported by vertical rods, which fit one into each shoe, a hole being formed for that purpose; and the point of support being very low, and quite close to the rail, great stability is insured. it is proposed to make the rail of the form shown in fig. in future, as this will avoid the plates, a, and the flanges, b, will help to keep the water on the rail. figs. , , and show the shoe in detail. fig. gives a longitudinal section, fig. is a plan, and fig. is a plan of the shoe inverted, showing the grooves in its face. fig. shows the hollow shoe, into which water at a pressure of ten atmospheres is forced by a pipe from a tank on the tender. the water enters by the pipe, c, and fills the whole of the chamber, d. the water attempts to escape, and in doing so lifts the shoe slightly, thus filling the first groove of the chamber. the pressure again lifts the shoe, and the second chamber is filled; and so on, until ultimately the water escapes at the ends, e, and sides, f. thus a film of water is kept between the shoe and the rail, and on this film the carriage is said to float. the water runs away into the channels, h h (fig. ), and is collected to be used over again. fig. also shows the means of supporting the carriage on the shoe by means of k, the point of support being very low. the system of grooves on the lower face of the shoe is shown in fig. . so much for the means by which wheels are dispensed with, and the carriage enabled to slide along the line. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] the next point is the method of propulsion. figs. and give an elevation and plan of one of the experimental carriages. along the under side of each of the carriages a straight turbine, l l, extends the whole length, and water at high pressure impinges on the blades of this turbine from a jet, m, and by this means the carriage is moved along. a parabolic guide, which can be moved in and out of gear by a lever, is placed under the tender, and this on passing strikes the tappet, s, and opens the valve which discharges the water from the jet, m, and this process is repeated every few yards along the whole line. the jets, m, must be placed at such a distance apart that at least one will be able to operate on the shortest train that can be used. in this turbine there are two sets of blades, one above the other, placed with their concave sides in opposite directions, so that one set is used for propelling in one direction and the other in the opposite direction. in fig. it is seen that the jet, m, for one direction is just high enough to act against the blades, q, while the other jet is higher, and acts on the blades, p, for propulsion in the opposite direction. the valves, r, which are opened by the tappet, s, are of peculiar construction, and we hope soon to be able to give details of them. reservoirs (fig. ) holding water at high pressure must be placed at intervals, and the pipe, t, carrying high pressure water must run the whole length of the line. fig. shows a cross section of the rail and carriage, and gives a good idea of the general arrangements. the absence of wheels and of greasing and lubricating arrangements will alone effect a very great saving, as we are informed that on the lyons railway, which is kilometers long, the cost of oil and grease exceeds £ , per annum. as sir edward watkin recently explained, all the great railway companies have long tried to find a substitute for wheels, and this railway appears to offer a solution of that problem. mons. barre thinks that a speed of kilometers (or miles) per hour may be easily and safely attained. [illustration: fig. .] [illustration: fig. .] of course, as there is no heavy locomotive, and as the traction does not depend upon pressure on the rail, the road may be made comparatively light. the force required to move a wagon along the road is very small, mons. barre stating, as the result of his experiments, that an effort amounting to less than half a kilogramme is sufficient to move one ton when suspended on a film of water with his improved shoes. it is recommended that the stations be placed at the summit of a double incline, so that on going up one side of the incline the motion of the train may be arrested, and on starting it may be assisted. no brakes are required, as the friction of the shoe against the rail, when the water under pressure is not being forced through, is found to be quite sufficient to bring the train to a standstill in a very short distance. the same water is run into troughs by the side of the line, and can be used over and over again indefinitely, and in the case of long journeys, the water required for the tender could be taken up while the train is running. the principal advantages claimed for the railway are: the absence of vibration and of side rolling motion; the pleasure of traveling is comparable to that of sleighing over a surface of ice, there is no noise, and what is important in town railways, no smoke; no dust is caused by the motion of the train during the journey. it is not easy for the carriages to be thrown from the rails, since any body getting on the rail is easily thrown off by the shoe, and will not be liable to get underneath, as is the case with wheels; the train can be stopped almost instantly, very smoothly, and without shock. very high speed can be attained; with water at a pressure of kilogrammes, a speed of kilometers per hour can be attained; great facility in climbing up inclines and turning round the curves; as fixed engines are employed to obtain the pressure, there is great economy in the use of coal and construction of boilers, and there is a total absence of the expense of lubrication. it is, however, difficult to see how the railway is to work during a long and severe frost. we hope to give further illustrations at an early date of this remarkable invention.--_industries._ * * * * * quartz fibers.[ ] [footnote : lecture delivered at the royal institution, on friday, june , by mr. c. v. boys, f.r.s.--_nature._] in almost all investigations which the physicist carries out in the laboratory, he has to deal with and to measure with accuracy those subtile and to our senses inappreciable forces to which the so-called laws of nature give rise. whether he is observing by an electrometer the behavior of electricity at rest or by a galvanometer the action of electricity in motion, whether in the tube of crookes he is investigating the power of radiant matter, or with the famous experiment of cavendish he is finding the mass of the earth--in these and in a host of other cases he is bound to measure with certainty and accuracy forces so small that in no ordinary way could their existence be detected, while disturbing causes which might seem to be of no particular consequence must be eliminated if his experiments are to have any value. it is not too much to say that the very existence of the physicist depends upon the power which he possesses of producing at will and by artificial means forces against which he balances those that he wishes to measure. i had better perhaps at once indicate in a general way the magnitude of the forces with which we have to deal. the weight of a single grain is not to our senses appreciable, while the weight of a ton is sufficient to crush the life out of any one in a moment. a ton is about , , grains. it is quite possible to measure with unfailing accuracy forces which bear the same relation to the weight of a grain that a grain bears to a ton. to show how the torsion of wires or threads is made use of in measuring forces, i have arranged what i can hardly dignify by the name of an experiment. it is simply a straw hung horizontally by a piece of wire. resting on the straw is a fragment of sheet iron weighing ten grains. a magnet so weak that it cannot lift the iron yet is able to pull the straw round through an angle so great that the existence of the feeble attraction is evident to every one in the room. now it is clear that if, instead of a straw moving over the table simply, we had here an arm in a glass case and a mirror to read the motion of the arm, it would be easy to observe a movement a hundred or a thousand times less than that just produced, and therefore to measure a force a hundred or a thousand times less than that exerted by this feeble magnet. again, if instead of wire as thick as an ordinary pin i had used the finest wire that can be obtained, it would have opposed the movement of the straw with a far less force. it is possible to obtain wire ten times finer than this stubborn material, but wire ten times finer is much more than ten times more easily twisted. it is ten thousand times more easily twisted. this is because the torsion varies as the fourth power of the diameter. so we say × = , × = , . therefore, with the finest wire, forces , times feebler still could be observed. it is therefore evident how great is the advantage of reducing the size of a torsion wire. even if it is only halved, the torsion is reduced sixteenfold. to give a better idea of the actual sizes of such wires and fibers as are in use, i shall show upon the screen a series of such photographs taken by mr. chapman, on each of which a scale of thousandths of an inch has been printed. [illustration: scale of ths of an inch for figs. to . the scale of figs. and is much finer.] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] the first photograph (fig. ) is an ordinary hair--a sufficiently familiar object, and one that is generally spoken of as if it were rather fine. much finer than this is the specimen of copper wire now on the screen (fig. ), which i recently obtained from messrs. nalder brothers. it is only a little over one-thousandth of an inch in diameter. ordinary spun glass, a most beautiful material, is about one-thousandth of an inch in diameter, and this would appear to be an ideal torsion thread (fig. ). owing to its fineness, its torsion would be extremely small, and the more so because glass is more easily deformed than metals. owing to its very great strength, it can carry heavier loads than would be expected of it. i imagine many physicists must have turned to this material in their endeavor to find a really delicate torsion thread. i have so turned only to be disappointed. it has every good quality but one, and that is its imperfect elasticity. for instance, a mirror hung by a piece of spun glass is casting an image of a spot of light on the scale. if i turn the mirror, by means of a fork, twice to the right, and then turn it back again, the light does not come back to its old point of rest, but oscillates about a point on one side, which, however, is slowly changing, so that it is impossible to say what the point of rest really is. further, if the glass is twisted one way first and then the other way, the point of rest moves in a manner which shows that it is not influenced by the last deflection alone: the glass remembers what was done to it previously. for this reason spun glass is quite unsuitable as a torsion thread; it is impossible to say what the twist is at any time, and therefore what is the force developed. [illustration: fig. .] so great has the difficulty been in finding a fine torsion thread that the attempt has been given up, and in all the most exact instruments silk has been used. the natural cocoon fibers, as shown on the screen (fig. ), consist of two irregular lines gummed together, each about one two-thousandth of an inch in diameter. these fibers must be separated from one another and washed. then each component will, according to the experiment of gray, carry nearly grains before breaking, and can be safely loaded with grains. silk is therefore very strong, carrying at the rate of from to tons to the square inch. it is further valuable in that its torsion is far less than that of a fiber of the same size of metal or even of glass, if such could be produced. the torsion of silk, though exceedingly small, is quite sufficient to upset the working of any delicate instrument, because it is never constant. at one time the fiber twists one way and another time in another, and the evil effect can only be mitigated by using large apparatus in which strong forces are developed. any attempt that may be made to increase the delicacy of apparatus by reducing their dimensions is at once prevented by the relatively great importance of the vagaries of the silk suspension. the result, then, is this. the smallness, the length of period, and therefore delicacy, of the instruments at the physicist's disposal have until lately been simply limited by the behavior of silk. a more perfect suspension means still more perfect instruments, and therefore advance in knowledge. it was in this way that some improvements that i was making in an instrument for measuring radiant heat came to a deadlock about two years ago. i would not use silk, and i could not find anything else that would do. spun glass, even, was far too coarse for my purpose, it was a thousand times too stiff. [illustration: fig. .] there is a material invented by wollaston long ago, which, however, i did not try because it is so easily broken. it is platinum wire which has been drawn in silver, and finally separated by the action of nitric acid. a specimen about the size of a single line of silk is now on the screen, showing the silver coating at one end (fig. ). as nothing that i knew of could be obtained that would be of use to me, i was driven to the necessity of trying by experiment to find some new material. the result of these experiments was the development of a process of almost ridiculous simplicity which it may be of interest for me to show. the apparatus consists of a small crossbow, and an arrow made of straw with a needle point. to the tail of the arrow is attached a fine rod of quartz which has been melted and drawn out in the oxyhydrogen jet. i have a piece of the same material in my hand, and now after melting their ends and joining them together, an operation which produces a beautiful and dazzling light, all i have to do is to liberate the string of the bow by pulling the trigger with one foot, and then if all is well a fiber will have been drawn by the arrow, the existence of which can be made evident by fastening to it a piece of stamp paper. in this way threads can be produced of great length, of almost any degree of fineness, of extraordinary uniformity, and of enormous strength. i do not believe, if any experimentalist had been promised by a good fairy that he might have anything he desired, that he would have ventured to ask for any one thing with so many valuable properties as these fibers possess. i hope in the course of this evening to show that i am not exaggerating their merits. [illustration: fig. .] [illustration: fig. .] in the first place, let me say something about the degree of fineness to which they can be drawn. there is now projected upon the screen a quartz fiber one five-thousandth of an inch in diameter (fig. ). this is one which i had in constant use in an instrument loaded with about grains. it has a section only one-sixth of that of a single line of silk, and it is just as strong. not being organic, it is in no way affected by changes of moisture and temperature, and so it is free from the vagaries of silk which give so much trouble. the piece used in the instrument was about inches long. had it been necessary to employ spun glass, which hitherto was the finest torsion material, then, instead of inches, i should have required a piece , feet long, and an instrument as high as the eiffel tower to put it in. there is no difficulty in obtaining pieces as fine as this yards long if required, or in spinning it very much finer. there is upon the screen a single line made by the small garden spider, and the size of this is perfectly evident (fig. ). you now see a quartz fiber far finer than this, or, rather, you see a diffraction phenomenon, for no true image is formed at all; but even this is a conspicuous object in comparison with the tapering ends, which it is absolutely impossible to trace in a microscope. the next two photographs, taken by mr. nelson, whose skill and resources are so famous, represent the extreme end of a tail of quartz, and, though the scale is a great deal larger than that used in the other photographs, the end will be visible only to a few. mr. nelson has photographed here what it is absolutely impossible to see. what the size of these ends may be, i have no means of telling. dr. royston piggott has estimated some of them at less than one-millionth of an inch, but, whatever they are, they supply for the first time objects of extreme smallness the form of which is certainly known, and, therefore, i cannot help looking upon them as more satisfactory tests for the microscope than diatoms and other things of the real shape of which we know nothing whatever. since figures as large as a million cannot be realized properly, it may be worth while to give an illustration of what is meant by a fiber one-millionth of an inch in diameter. a piece of quartz an inch long and an inch in diameter would, if drawn out to this degree of fineness, be sufficient to go all the way round the world times; or a grain of sand just visible--that is, one-hundredth of an inch long and one hundredth of an inch in diameter--would make one thousand miles of such thread. further, the pressure inside such a thread due to a surface tension equal to that of water would be atmospheres. going back to such threads as can be used in instruments, i have made use of fibers one ten-thousandth of an inch in diameter, and in these the torsion is , times less than that of spun glass. as these fibers are made finer their strength increases in proportion to their size, and surpasses that of ordinary bar steel, reaching, to use the language of engineers, as high a figure as tons to the inch. fibers of ordinary size have a strength of tons to the inch. while it is evident that these fibers give us the means of producing an exceedingly small torsion, and one that is not affected by weather, it is not yet evident that they may not show the same fatigue that makes spun glass useless. i have, therefore, a duplicate apparatus with a quartz fiber, and you will see that the spot of light comes back to its true place on the screen after the mirror has been twisted round twice. i shall now for a moment draw your attention to that peculiar property of melted quartz that makes threads such as i have been describing a possibility. a liquid cylinder, as plateau has so beautifully shown, is an unstable form. it can no more exist than can a pencil stand on its point. it immediately breaks up into a series of spheres. this is well illustrated in that very ancient experiment of shooting threads of resin electrically. when the resin is hot, the liquid cylinders, which are projected in all directions, break up into spheres, as you see now upon the screen. as the resin cools, they begin to develop tails; and when it is cool enough, i.e., sufficiently viscous, the tails thicken and the beads become less, and at last uniform threads are the result. the series of photographs show this well. [illustration: fig. .] [illustration: fig. .] there is a far more perfect illustration which we have only to go into the garden to find. there we may see in abundance what is now upon the screen--the webs of those beautiful geometrical spiders. the radial threads are smooth like the one you saw a few minutes ago, but the threads that go round and round are beaded. the spider draws these webs slowly, and at the same time pours upon them a liquid, and still further to obtain the effect of launching a liquid cylinder in space he, or rather she, pulls it out like the string of a bow, and lets it go with a jerk. the liquid cylinder cannot exist, and the result is what you now see upon the screen (fig. ). a more perfect illustration of the regular breaking up of a liquid cylinder it would be impossible to find. the beads are, as plateau showed they ought to be, alternately large and small, and their regularity is marvelous. sometimes two still smaller beads are developed, as may be seen in the second photograph, thus completely agreeing with the results of plateau's investigations. i have heard it maintained that the spider goes round her web and places these beads there afterward. but since a web with about , beads is completed in an hour--that is at the rate of about a second--this does not seem likely. that what i have said is true, is made more probable by the photograph of a beaded web that i have made myself by simply stroking a quartz fiber with a straw wetted with castor oil (fig. ); it is rather larger than a spider line; but i have made beaded threads, using a fine fiber, quite indistinguishable from a real spider web, and they have the further similarity that they are just as good for catching flies. now, going back to the melted quartz, it is evident that if it ever became perfectly liquid, it could not exist as a fiber for an instant. it is the extreme viscosity of quartz, at the heat even of an electric arc, that makes these fibers possible. the only difference between quartz in the oxyhydrogen jet and quartz in the arc is that in the first you make threads and in the second are blown bubbles. i have in my hand some microscopic bubbles of quartz showing all the perfection of form and color that we are familiar with in the soap bubble. an invaluable property of quartz is its power of insulating perfectly, even in an atmosphere saturated with water. the gold leaves now diverging were charged some time before the lecture, and hardly show any change, yet the insulator is a rod of quartz only three-quarters of an inch long, and the air is kept moist by a dish of water. the quartz may even be dipped in the water and replaced with the water upon it without any difference in the insulation being observed. not only can fibers be made of extreme fineness, but they are wonderfully uniform in diameter. so uniform are they that they perfectly stand an optical test so severe that irregularities invisible in any microscope would immediately be made apparent. every one must have noticed when the sun is shining upon a border of flowers and shrubs how the lines which spiders use as railways to travel from place to place glisten with brilliant colors. these colors are only produced when the fibers are sufficiently fine. if you take one of these webs and examine it in the sunlight, you will find that the colors are variegated, and the effect, consequently, is one of great beauty. a quartz fiber of about the same size shows colors in the same way, but the tint is perfectly uniform on the fiber. if the color of the fiber is examined with a prism, the spectrum is found to consist of alternate bright and dark bands. upon the screen are photographs taken by mr. briscoe, a student in the laboratory at south kensington, of the spectra of some of these fibers at different angles of incidence. it will be seen that coarse fibers have more bands than fine, and that the number increases with the angle of incidence of the light. there are peculiarities in the march of the bands as the angle increases which i cannot describe now. i may only say that they appear to move not uniformly, but in waves, presenting very much the appearance of a caterpillar walking. so uniform are the quartz fibers that the spectrum from end to end consists of parallel bands. occasionally a fiber is found which presents a slight irregularity here and there. a spider line is so irregular that these bands are hardly observable; but, as the photograph on the screen shows, it is possible to trace them running up and down the spectrum when you know what to look for. to show that these longitudinal bands are due to the irregularities, i have drawn a taper piece of quartz by hand, in which the two edges make with one another an almost imperceptible angle, and the spectrum of this shows the gradual change of diameter by the very steep angle at which the bands run up the spectrum. into the theory of the development of these bands i am unable to enter; that is a subject on which your professor of natural philosophy is best able to speak. perhaps i may venture to express the hope, as the experimental investigation of this subject is now rendered possible, that he may be induced to carry out a research for which he is so eminently fitted. though this is a subject which is altogether beyond me, i have been able to use the results in a practical way. when it is required to place into an instrument a fiber of any particular size, all that has to be done is to hold the frame of fibers toward a bright and distant light, and look at them through a low-angled prism. the banded spectra are then visible, and it is the work of a moment to pick out one with the number of bands that has been found to be given by a fiber of the desired size. a coarse fiber may have a dozen or more, while such fibers as i find most useful have only two dark bands. much finer ones exist, showing the colors of the first order with one dark band; and fibers so fine as to correspond to the white or even the gray of newton's scale are easily produced. passing now from the most scientific test of the uniformity of these fibers, i shall next refer to one more homely. it is simply this: the common garden spider, except when very young, cannot climb up one of the same size as the web on which she displays such activity. she is perfectly helpless, and slips down with a run. after vainly trying to make any headway, she finally puts her hands (or feet) into her mouth and then tries again, with no better success. i may mention that a male of the same species is able to run up one of these with the greatest ease, a feat which may perhaps save the lives of a few of these unprotected creatures when quartz fibers are more common. it is possible to make any quantity of very fine quartz fiber without a bow and arrow at all, by simply drawing out a rod of quartz over and over again in a strong oxyhydrogen jet. then, if a stand of any sort has been placed a few feet in front of the jet, it will be found covered with a maze of thread, of which the photograph on the screen represents a sample. this is hardly distinguishable from the web spun by this magnificent spider in corners of greenhouses and such places. by regulating the jet and the manipulation, anything from one of these stranded cables to a single ultro-microscope line may be developed. and now that i have explained that these fibers have such valuable properties, it will no doubt be expected that i should perform some feat with their aid which, up to the present time, has been considered impossible, and this i intend to do. of all experiments, the one which has most excited my admiration is the famous experiment of cavendish, of which i have a full size model before you. the object of this experiment is to weigh the earth by comparing directly the force with which it attracts things with that due to large masses of lead. as is shown by the model, any attraction which these large balls exert on the small ones will tend to deflect this ft. beam in one direction, and then if the balls are reversed in position, the deflection will be in the other direction. now, when it is considered how enormously greater the earth is than these balls, it will be evident that the attraction due to them must be in comparison excessively small. to make this evident, the enormous apparatus you see had to be constructed, and then, using a fine torsion wire, a perfectly certain but small effect was produced. the experiment, however, could only be successfully carried out in cellars and underground places, because changes of temperature produced effects greater than those due to gravity.[ ] [footnote : dr. lodge has been able, by an elaborate arrangement of screens, to make this attraction just evident to an audience.--c. v. b.] now i have in a hole in the wall an instrument no bigger than a galvanometer, of which a model is on the table. the balls of the cavendish apparatus, weighing several hundredweight each, are replaced by balls weighing ¾ pounds only. the smaller balls of ¾ pounds are replaced by little weights of grains each. the foot beam is replaced by one that will swing round freely in a tube three-quarters of an inch in diameter. the beam is, of course, suspended by a quartz fiber. with this microscopic apparatus, not only is the very feeble attraction observable, but i can actually obtain an effect eighteen times as great as that given by the apparatus of cavendish, and what is more important, the accuracy of observation is enormously increased. the light from a lamp passes through a telescope lens, and falls on the mirror of the instrument. it is reflected back to the table, and thence by a fixed mirror to the scale on the wall, where it comes to a focus. if the mirror on the table were plane, the whole movement of the light would be only about eight inches, but the mirror is convex, and this magnifies the motion nearly eight times. at the present moment the attracting weights are in one extreme position, and the line of light is quiet. i will now move them to the other position, and you will see the result--the light slowly begins to move, and slowly increases in movement. in forty seconds it will have acquired its highest velocity, and in forty more it will have stopped at feet ½ inches from the starting point, after which it will slowly move back again, oscillating about its new position of rest. it is not possible at this hour to enter into any calculations; i will only say that the motion you have seen is the effect of a force of less than one ten-millionth of the weight of a grain, and that with this apparatus i can detect a force two thousand times smaller still. there would be no difficulty even in showing the attraction between two no. shot. and now, in conclusion, i would only say that if there is anything that is good in the experiments to which i have this evening directed your attention, experiments conducted largely with sticks, and string, and straw and sealing wax, i may perhaps be pardoned if i express my conviction that in these days we are too apt to depart from the simple ways of our fathers, and instead of following them, to fall down and worship the brazen image which the instrument maker hath set up. * * * * * nature, composition, and treatment of animal and vegetable fabrics. the inseparable duties of studying the composition of the various animal and vegetable fabrics, as also their nature--when in contact with the various mineral, vegetable, animal, and gaseous bodies applied in the individual industries--should not devolve upon the heads, chemists, or managers of firms alone. it is most important that every intelligent workman, whom we cannot expect to acquire a very extensive knowledge of chemistry and perfect acquaintance of the particular nature and component parts of fabrics, should, at least, be able to thwart the possibility of the majority of accidents brought about in regard to the quality and aspect of materials treated by them. in the treatment of wool the first operations are of no mean importance, and the whole subsequent operations and final results, almost as a whole, depend on the manner in which the fleece washing had been effected. in presence of suintine, as also fatty matters, as well as the countless kinds of acids deposited on the wool through exudation from the body, etc., the various agents and materials cannot act and deposit as evenly as might be desired, and the complete obliteration of the former, therefore, becomes an absolute necessity. for vegetable fabrics a great technical and practical knowledge is already requisite in their cultivation itself, and before any operations are necessary at all. one of the greatest points is the ripeness of the fibers. it is almost an impossibility to produce delicate colors on vegetable fabrics which were gathered inopportunely. numerous experiments have been made on cotton containing smaller or larger quantities of unripe fibers, and after the necessary preceding operations, have been dyed in rose, purple, and blue colors, and the beauty of the shades invariably differed in proportion to the greater or lesser quantities of unripe fibers contained in the samples, and by a careless admixture of unripe and unseasoned fibers the most brilliant colors have been completely spoiled in the presence of the former. these deficiencies of unripe vegetable fibers are so serious that the utmost precautions should be taken, not only by planters to gather the fibers in a ripe state, but the natural aspect of ripe and unripe fibers and their respective differences should be known to the operators of the individual branches in the cotton industry themselves. the newest vegetable fabrics, as _ma_ (china grass), pina, _abaca_, or manila hemp, _agave_, jute, and that obtained from the palm tree, must be tended with equal care to that of cotton. the _ma_, or china grass, is obtained from the _boehmeria nivea_, as also from the less known _boehmeria puya_. the fibers of this stalk, after preparing and bleaching, have the whiteness of snow and the brilliancy of silk. by a special process--the description of which we must for the present leave in abeyance--the china grass can be transformed into a material greatly resembling the finest quality of wool. the greatest advantage afforded in the application of china grass is, moreover, that the tissues produced with this fiber are much more easily washed than silks, and in this operation they lose none of their beauty or their quality. the _abaca_ is produced from the fibrous parts of the bark of the wild banana tree, found in the philippines. its botanical denomination is _musa troglodytarum_. the _abaca_ fiber is not spun or wrung, but is jointed end to end. the threads are wound and subsequently beaten for softening, and finally bleached by plunging in lime water for twenty-four hours, and dried in the sun. the _pina_ is a fiber obtained from the leaf of the anana tree (_bromelias ananas_), and is prepared in the same way as the abaca, but extreme care must in this case be observed in culling the fibers, in order to sort in accordance with their degree of fineness. the arabs manufacture the stuff for their tents with a mixture of camel's hair and the fibrous flocks (kind of wadding) obtained from the stalks of the wafer palm (the _chamærops humilis_). the tissues used by the arabs are coarse and colored, but the palm fibers--when freed from gluten, which makes them adhere more strongly--are susceptible to divide in a most astonishing manner. the _agave americana_ is a coarse fiber, mostly used in france for the manufacture of gobelin carpets and the production of ropes. great efforts have been made to bleach it in a satisfactory manner, as is done with the _phormium tenax_, but the former kind of fiber resists the ordinary treatment with lyes, etc., and an appropriate bleaching process has only been discovered quite recently. jute, which by many is confounded with _phormium tenax_, or new zealand lint, is a fiber which can be divided as finely as desired, and can be most beautifully bleached. the jute or indian _paat_ is generally known as a fibrous and textile fabric, obtained chiefly from calcutta, and is similar in nature to the _corchorus capsularis_, an oriental species, known in oriental india by the name of _hatta jute_ and _gheenatlapaat_. this fibrous plant has the property of dividing into the finest parallel fibers, which can be carded without difficulty, and may be said to have the excellent properties of linen, hemp, and cotton at once. when properly bleached, it has an aspect which is as beautiful as that of silk. a mixture of silk and jute can be easily worked together, and can also be mixed with such vegetable fibers as cotton and linen. an immense quantity of flannel and other stuffs are now manufactured and imitated with the different mixtures containing jute. the _suun_ is a fiber of a plant in the form of a cane (_crotalaria juncea_), and the paat or _suncheepaat_ is the thread of a species of spiral (_corchorus olitarius_), sold under the name of jute tissues. the cotton tissues lose about twenty-five per cent. of their weight in bleaching, five per cent. of the substances are dissolved through alkalies, and the other twenty per cent., which are not attacked directly through the alkalies, are removed through chlorine, acids, and the water itself. the linen and hemp tissues contain eighteen per cent. of substances which are soluble in alkalies, and they lose from twenty-seven to thirty per cent. of their weight when taken through the consecutive bleaching operations. the substances do not alone include the substances contained in the fabric originally, but also such as are deposited in the preliminary treatment of the fabrics, as dirt from the hands of the operator, and gluten soluble in warm water; as also glue or gelatine, potash or soda, starch, albumen, and sugar, used by weavers, etc., and which are all soluble in water; further, such as greasy matters, calcareous soap, coppery soap, resinous or gummo-resinous matters, and the yellow and green coloring matters contained in textile fabrics, which are soluble in caustic soda; and finally, the earthy constituents which are soluble in acids. the nature and composition of silk and wool is diametrically opposed to that of the former. the silk is more of a gummy nature, and is susceptible to decompose into a kind of gelatinous mass if specially treated. the yellow coloring principle in silk was found only to be contained in a very small proportion, and consisting of several distinct bodies. the wool contains, first, a fatty matter which is solid at an ordinary temperature, and perfectly liquid at ° c.; secondly, a fatty matter which is liquid at ° c.; thirdly, a fibrous substance which essentially constitutes the wool in the strict sense of the word. the wool at least contains three important principles, as it will be known that the fibrous substance disengages sulphur and hydro-sulphuric acid without losing its peculiar properties; and it, therefore, appears probable that the sulphur entered as an element in the composition of a body which is perfectly distinct from the fibrous substance aforementioned. in treating wool with nitric acid, and taking all possible precautions to determine as accurately as possible the quantity of sulphuric acid produced by the contents of sulphur in the wool by the reaction with chloride of barium, it will be found to contain from . to . per cent. of sulphur.--_wool and textile fabrics._ * * * * * the production of ammonia from coal.[ ] by ludwig mond. [footnote : a paper read at the annual general meeting of the society of chemical industry, london, july , .] as exemplifying to a certain extent the application of methodical research to an industrial problem, i propose to bring before you to-day an account of the work i have been engaged in for many years in relation to the procuring of new and abundant supplies of ammonia, and to investigations connected therewith. through the classic researches of lawes and gilbert, who proved, in opposition to no less an authority than liebig, that ammonia is a most valuable manure which enables us not only to maintain, but to multiply, the yield of our fields, and thus to feed on the same area a much larger number of inhabitants, the immense importance of an abundant supply of ammonia, more particularly for the old world, with its teeming population and worn-out soil, has been apparent to every one. for many years europe has paid to south america millions upon millions of pounds for ammonia in the shape of guano, and more recently, since the supply of guano practically ceased, for nitrate of soda, which effectually serves the same purpose as ammonia. during the past year south america exported , tons of nitrate, of which , went to europe, representing a value of not less than , , l. the problem of saving this immense expenditure to europe, of making ourselves independent of a country so far away for the supply of a material upon which the prosperity of our agriculture--our most important industry--depends, by supplying this ammonia from sources at our own command, is certainly one of the most important which our science has to solve. it is more than years since berthollet ascertained that ammonia consists of nitrogen and hydrogen, two elements which we have in great abundance at our command, and innumerable attempts have been made during this century to produce this valuable product by the direct combination of the elements, as well as by indirect means. it has been equally well known that we are in possession of three abundant sources of nitrogen: ( .) in the shape of matter of animal origin. ( .) in the shape of matter of vegetable origin. ( .) in the atmosphere, which contains no less than per cent. of uncombined nitrogen. in olden times ammonia was principally obtained from animal matter, originally in egypt by the distillation of camel dung, later on from urine, and from the distillation of bones and horn. the quantity so obtained was very small and the products very expensive. the introduction of coal gas for illumination gave us a considerable and constantly increasing supply of ammonia as a by-product of the gas manufacture, and until recently all practical efforts to increase our supply of ammonia were directed toward collecting and utilizing in the best possible manner the ammonia so obtained. the immense extension of the coal gas industry all over the world has in this way put us into possession of a very considerable amount of sulphate of ammonia, amounting in europe now to , tons per annum. in recent years this has been augmented by the ammonia obtained by the distillation of shale, by the introduction of closed ovens for the manufacture of coke, combined with apparatus for condensing the ammonia formed in this manufacture, and also by the condensation of the ammonia contained in the gases from blast furnaces working with coal. but all these new sources have so far added only about , tons of sulphate of ammonia to our supply, making a total of , tons per annum, of which about , are produced in the united kingdom, while we still import , tons of nitrate of soda, equivalent to , tons of sulphate of ammonia, to make up our requirements. many processes have from time to time been proposed to obtain ammonia from other sources. the distillation of turf, which contains upward of per cent. of nitrogen, has received much attention, and a large number of inventors have endeavored to produce ammonia from the nitrogen of the air; but none of these processes has to my knowledge been successful on a manufacturing scale. my attention was called to this subject at an early part of my career. already, as far back as , i undertook experiments to utilize, for the production of ammonia, waste leather, a waste material of animal origin at once abundant and very rich in nitrogen, containing from per cent. to per cent. of this element. distillation in iron retorts yielded about half the nitrogen of this material in the form of ammonia, the carbon remaining in the retorts containing still from per cent. to per cent. distillation with a moderate quantity of hydrate of lime increased the yield of ammonia only by per cent. to ½ per cent. a rather better result was obtained by distilling the ground residual carbon with hydrate of lime, but this operation proceeded very slowly, and the total yield of ammonia still remained very far below the quantity theoretically obtainable, so that i came to the conclusion that it was more rational to utilize the leather, reduced to powder by mechanical means, by mixing it directly with other manures. a few years later i became connected with a large animal charcoal works, in which sulphate of ammonia was obtained as a by-product. here again i was met with the fact that the yield of ammonia by no means corresponded with the nitrogen in the raw material and that the charcoal remaining in the retorts contained still about half as much nitrogen as had been present in the bones used. from this time forward my attention was for many years given exclusively to the soda manufacture, and it was only in that i again took up the question of ammonia. i then determined to submit the various processes which had been proposed for obtaining ammonia from the nitrogen of the air to a searching investigation, and engaged mr. joseph hawliczek to carry out the experimental work. these processes may be broadly divided into three classes: ( .) processes which propose to combine nascent hydrogen with nitrogen at high temperatures or by electricity, with or without the presence of acid gases. ( .) processes in which nitrides are first formed, from which ammonia is obtained by the action of hydrogen or steam. ( .) processes in which cyanides are first formed and the ammonia obtained from these by the action of steam. we began with an investigation of those processes in which a mixture of steam and nitrogen or of steam and air is made to act upon coke at a high temperature, sometimes in the presence of lime, baryta, or an alkali, sometimes in the presence of hydrochloric acid. very numerous patents have been taken out in this direction and there is no doubt that ammonia has been obtained by these processes by many inventors, but as i was aware that coke contains a considerable quantity of nitrogen, frequently as much as . per cent., which might be the source of the ammonia obtained, i determined to carry on the investigation in such a way as to make quite certain whether we obtained the ammonia from the coke or from the nitrogen of the atmosphere, or from both. for this purpose we made for every experiment carried on by a mixture of nitrogen or air with steam another experiment with steam alone, carefully excluding nitrogen from the apparatus. a very large number of experiments carried on at carefully determined temperatures, ranging from ° to , °c., and in which the directions given by the various inventors were most carefully observed, all led to the same result, viz., that the quantities of ammonia obtained were the same whether nitrogen was introduced into the apparatus with the steam or whether steam alone was used, thus proving conclusively that the ammonia obtained was derived from the nitrogen contained in the coke. further, on carefully determining the nitrogen in the coke used, it was found that the quantity of ammonia we had obtained in burning coke in a current of nitrogen and steam very nearly corresponded with the total nitrogen in the coke, so that we subsequently made our nitrogen determinations in the coke by simply burning it in a current of steam. a process belonging to this class, proposed by hugo fleck, in which a mixture of carbonic oxide, steam, and nitrogen is made to pass over lime at a moderate red heat in order to obtain ammonia, was also carefully tried. it was claimed for this process that it produced nascent hydrogen at temperatures at which the ammonia is not dissociated, and for this reason succeeded where others had failed. we found that a considerable amount of hydrogen was obtained in this way at a temperature not exceeding °c., and that the reaction was nearly complete at °c.; but although we tried many experiments over a great range of temperatures, we never obtained a trace of ammonia by this process. among experiments with processes of the second class, based upon the formation of nitrides and their subsequent decomposition, the nitrides of boron and titanium had received most attention from inventors. the nitride of boron, which is obtained by treating boracic acid with carbon in the presence of nitrogen, when acted upon by steam, forms boracic acid again and yields the whole of its nitrogen in the form of ammonia, but the high temperature at which the first reaction takes place, and the volatility of boracic acid in a current of steam, make it impossible to utilize this reaction industrially. there seemed to be a better chance for a process patented by m. tessier du mothay, who proposed to bring a mixture of nitrogen and hydrogen into contact with titanium nitride and thus to form ammonia continuously. titanium is the only element of which we know at present several combinations with nitrogen, and the higher of these does, on being acted upon by a current of hydrogen at an elevated temperature, produce ammonia and a lower nitride of titanium; but this lower nitride does not absorb nitrogen under any of the conditions under which we tried it, which explains the fact that if we passed a current of hydrogen and nitrogen over the higher nitride, we at first obtained a quantity of ammonia corresponding to the quantity which the nitride would give with hydrogen alone, but that the formation of ammonia then ceased completely. thus far we had quite failed to get the nitrogen of the air into action. with the third class of processes, however, based upon the formation in the first instance of cyanides, we found by our very first experiments that the nitrogen of the atmosphere can be easily led into combination. a few experiments showed that the cyanide of barium was much more readily formed than any other cyanide; so we gave our full attention from this time to the process for obtaining ammonia by means of cyanide of barium invented by mm. margueritte and sourdeval. this process consists in heating a mixture of carbonate of barium with carbon in the presence of nitrogen, and subsequently treating the cyanide of barium produced with steam, thus producing ammonia and regenerating the carbonate of barium. a great difficulty in this process is that the carbonate of barium fuses at high temperatures, and when fused attacks fireclay goods very powerfully. we found that this can be overcome by mixing the carbonate of barium with a sufficient quantity of carbon and a small quantity of pitch, and that in this way balls can be made which will not fuse, so that they can be treated in a continuous apparatus in which the broken briquettes can be charged from the top, and after treatment can be withdrawn from the bottom. we found that the formation of cyanides required a temperature of at least , ° c., and proceeded most readily at , ° c., temperatures which, although difficult to attain, are still quite within the range of practical working, and we found no difficulty in obtaining a product containing per cent. of barium cyanide, corresponding to a conversion into cyanide of per cent. of the barium present. we found, however, that the cyanide when exposed to the atmosphere at a temperature above ° c. is readily destroyed under reformation of carbonate of barium, so that it is absolutely necessary to cool it down to this temperature before exposing it to the atmosphere, a fact of great importance that had hitherto been overlooked. the operation for producing ammonia and regenerating the carbonate of barium by acting upon the cyanide with steam offers no difficulty whatever, and if the temperature is not allowed to exceed ° c., the results are quantitative. the regenerated carbonate of barium acts actually better than the ground witherite used in the first instance, and if care is taken that no impurities are introduced by the pitch which is used to remake the briquettes and to replace the small amount of carbon consumed at each operation, i see no reason why it should not continue to act for a very long time. the cyanide is not acted on by carbonic oxide, but carbonic acid destroys it at high temperatures, so that it is not possible to produce it by heating the briquettes directly in a flame free from oxygen, but containing carbonic acid. the process has, therefore, to be carried out in closed vessels, and i designed for this purpose the following apparatus: clay retorts of moderate dimensions and thin walls are placed vertically in a furnace, passing through the hearth as well as through the arch of the furnace. these are joined at the bottom to cast iron retorts of the same shape as the earthenware retort. through a cast iron mouthpiece on the top of the retort the material was introduced, while in the cast iron retort below the material was cooled to the necessary temperature by radiation and by the cold nitrogen gas introduced into the bottom of it. the lower end of the cast iron retort was furnished with an arrangement for taking out from time to time small quantities of the material, while fresh material was in the same proportion fed in at the top. as a source of nitrogen i used the gases escaping from the carbonating towers of the ammonia-soda process. the formation of cyanide of barium from barium carbonate, carbon, and nitrogen absorbs a very large amount of heat--no less than , calories per equivalent of the cyanide formed--which heat has to be transmitted through the walls of the retort. i therefore considered it necessary to use retorts with very thin walls, but i did not succeed in obtaining retorts of this description which would resist the very high temperatures which the process requires, and for this reason i abandoned these experiments. i was at that time not acquainted with the excellent quality of clay retorts used in zinc works, with which i have since experimented for a different purpose. i have no doubt that with such retorts the production of cyanides by this process can be carried out without great difficulty. i believe that the process will prove remunerative for the manufacture of cyanogen products, which, if produced more cheaply, may in the future play an important role in organic synthesis, in the extraction of noble metals, and possibly other chemical and metallurgical operations. the process certainly also offers a solution of the problem of obtaining ammonia from the nitrogen of the atmosphere, but whether this can be done with satisfactory commercial results is a question i cannot at present answer, as i have not been able to secure the data for making the necessary calculations. i am the more doubtful about this point, as in the course of our investigations i have found means to produce ammonia at small cost and in great abundance from the immense store of combined nitrogen which we possess in our coal fields. among the processes for obtaining ammonia from the nitrogen of the air which we investigated, was one apparently of great simplicity, patented by messrs. rickman and thompson. these gentlemen state that by passing air and steam through a deep coal fire, the nitrogen so passed through is to a certain extent converted into ammonia. in investigating this statement we found that the process described certainly yields a considerable quantity of ammonia, but when we burned the same coal at a moderate temperature by means of steam alone in a tube heated from the outside, we obtained twice as much ammonia as we had done by burning it with a mixture of air and steam, proving in this case, as in all others, the source of the ammonia to have been the nitrogen contained in the coal. the quantity of ammonia obtained was, however, so large that i determined to follow up this experience, and at once commenced experiments on a semi-manufacturing scale to ascertain whether they would lead to practical and economic results. i came to the conclusion that burning coal by steam alone at a temperature at which the ammonia formed should not be dissociated, although it yielded more ammonia, would not lead to an economic process, because it would require apparatus heated from the outside, of great complication, bulk, and costliness, on account of the immense quantity of raw material to be treated for a small amount of ammonia obtainable. on the other hand, if the coal could be burned in gas producers by a mixture of air and steam, the plant and working of it would be simple and inexpensive, the gas obtained could be utilized in the same way as ordinary producer gas, and would pay to a large extent for the coal used in the operation, so that although only one-half of the ammonia would be obtained, it seemed probable that the result would be economical. i consequently constructed gas producers and absorbing plant of various designs and carried on experiments for a number of years. these experiments were superintended by mr. g. h. beckett, dr. carl markel, and, during the last four years, by dr. adolf staub, to whose zeal and energy i am much indebted for the success that has been achieved. the object of these experiments was to determine the most favorable conditions for the economic working of the process with respect to both the cost of manufacture as well as the first cost and simplicity of plant. the cost of manufacture depends mainly upon the yield of ammonia, as the expenses remain almost the same whether a large or a small amount of ammonia is obtained; the only other item of importance is the quantity of steam used in the process. we found the yield of ammonia to vary with the temperature at which the producer was working, and to be highest when the producer was worked as cool as was compatible with a good combustion of the fuel. the temperature again depended upon the amount of steam introduced into the producer, and of course decreased the more steam increased. we obtained the best practical results by introducing about two tons of steam for every ton of fuel consumed. we experimented upon numerous kinds of fuel, common slack and burgy of the lancashire, staffordshire, and nottinghamshire districts. we found not much difference in the amount of nitrogen contained in these fuels, which varied between . and . per cent., nor did we find much difference in the ammonia obtained from these fuels if worked under similar conditions. employing the quantity of steam just named we recovered about half the nitrogen in the form of ammonia, yielding on an average . per cent. of ammonia, equal to kilos, of sulphate per ton of fuel. in order to obtain regular results we found it necessary to work with a great depth of fuel in the producers, so that slight irregularities in the working would not affect results. open burning kinds of slack do of course work with the greater ease, but there is no difficulty in using a caking fuel, as the low temperature at which the producers work prevents clinkering and diminishes the tendency of such fuels to cake together. the quantity of steam thus required to obtain a good yield of ammonia is rather considerable, and threatened to become a serious item of expense. only one-third of this steam is decomposed, in its passage through the producer, and two-thirds remain mixed with the gases which leave the producer. my endeavors were consequently directed toward finding means to recover this steam, and to return it to the producers, and also to utilize the heat of the gases which leave the producers with a temperature of ° to ° c., for raising steam for the same purpose. the difficulties in the way of attaining this end and at the same time of recovering, in a simple manner, the small amount of ammonia contained in the immense volume of gas we have to deal with, were very great. we obtain from one ton of coal , cubic feet of dry gas at ° c. and atmospheric pressure. the steam mixed with this gas as it leaves the producer adds another , cubic feet to this, and the large amount of latent heat in this quantity of steam makes the problem still more difficult. the application of cooling arrangements, such as have been successfully applied to blast furnace gases, in which there is no steam present, and which depend upon the cooling through the metallic sides of the apparatus, is here practically out of the question. after trying a number of different kinds of apparatus, i have succeeded in solving the problem in the following way: the gases issuing from the producers are led through a rectangular chamber partly filled with water, which is thrown up in a fine spray by revolving beaters so as to fill the whole area of the chamber. this water, of course, becomes hot; a certain quantity of it evaporates, the spray produced washes all dust and soot out of the gases, and also condenses the fixed ammonia. the water thus becomes, to a certain degree, saturated with ammonia salts, and a certain portion of it is regularly removed from the chamber and distilled with lime to recover the ammonia. [illustration: longitudinal section of plant for obtaining ammonia from gas producers. cross section through gas producers.] this chamber is provided with water lutes, through which the tar condensed in it is from time to time removed. from this chamber the gases, which are now cooled down to about ° c., and are loaded with a large amount of water vapor, are passed through a scrubber filled with perforated bricks, in which the ammonia contained in the gases is absorbed by sulphuric acid. in this scrubber a fairly concentrated solution of sulphate of ammonia containing to per cent. is used, to which a small quantity of sulphuric acid is added, so that the liquid leaving the scrubber contains only . per cent. of free acid. this is necessary, as a liquid containing more acid would act upon the tarry matter and produce a very dark-colored solution. the liquid running from the scrubber is passed through a separator in which the solution of sulphate of ammonia separates from the tar. the greater portion of the clear liquid is, after adding a fresh quantity of acid to it, pumped back through the scrubber. a certain portion of it is, after treatment with a small quantity of heavy tar oils, which take the tarry matter dissolved in it out, evaporated in conical lead-lined pans furnished with lead steam coils, and which are kept constantly filled by the addition of fresh liquor until the whole mass is thick. this is then run out on a strainer and yields, after draining and washing with a little water, a sulphate of ammonia of very fair quality, which finds a ready sale. the mother liquor, which contains all the free acid, is pumped back to the scrubber. the gas on entering this scrubber contains only . volume per cent. of ammonia, and on leaving the scrubber it contains not more than one-tenth of this quantity. its temperature has been reduced to ° c., and is fully saturated with moisture, so that practically no condensation of water takes place in the scrubber. the gas is next passed through a second scrubber filled with perforated wood blocks. in this it meets with a current of cold water which condenses the steam, the water being thereby heated to about ° c. in this scrubber the gas is cooled down to about °- ° c., and passes from it to the gas main leading to the various places where it is to be consumed. the hot water obtained in this second scrubber is passed through a vessel suitably constructed for separating the tar which is mixed with it, and is then pumped through a third scrubber, through which, in an opposite direction to the hot water, cold air is passed. this is forced by means of a roots blower through the scrubber into the producer. the air gets heated to about ° c. and saturated with moisture at that temperature by its contact with the hot water, and the water leaves this third scrubber cold enough to be pumped back through the second scrubber. the same quantity of water is thus constantly used for condensing the water vapor in one scrubber and giving it up to the air in the other. in this way we recover and return to the producer fully two-thirds of the steam which has been originally introduced, so that we have to add to the air, which has thus been loaded with moisture, an additional quantity of steam equal to only one-third of the total quantity required before it enters the producer. this additional quantity of steam, which amounts to . ton of steam for every ton of fuel burnt, we obtain as exhaust steam from the engines driving the blowers and pumps required for working the plant. the gas producers which i prefer to use are of rectangular shape, so that a number of them can be put into a row. they are six feet wide and feet long inside. the air is introduced and the ashes removed at the two small sides of the producer which taper toward the middle and are closed at the bottom by a water lute of sufficient depth for the pressure under which the air is forced in, equal to about inches of water. the ashes are taken out from underneath the water, the producers having no grate or fire bars at all. the air enters just above the level of the water through a pipe connected with the blower. these small sides of the producer rest upon cast iron plates lined to a certain height with brickwork, and this brickwork is carried by horizontal cast iron plates above the air entrance. in this way a chamber is formed of triangular shape, one side of which is closed by the ashes, and thus the air is distributed over the whole width of the producer. the gas is taken out in the middle of the top of the producer by an iron pipe, and fuel charged in by hoppers on both sides of this pipe. between the pipe and the hoppers two hanging arches are put into the producers a certain distance down, and the fuel is kept above the bottom level of these hanging arches. this compels the products of distillation, produced when fresh fuel is charged in, to pass through the incandescent fuel between the two hanging arches, whereby the tarry products are to a considerable extent converted into permanent gas, and the coal dust arising from the charging is kept back in the producer. the details of construction of this plant will be easily understood by reference to the diagrams before you. the fuel we use is a common kind of slack, and contains, on an average, . per cent. of volatile matter, including water, and . per cent. of ashes, leaving per cent. of non-volatile carbon. the cinders which we take out of the producer contain, on an average, per cent. of carbon. of this we recover about one-half by riddling or picking, which we return to the producer. the amount of unburnt carbon lost in the cinders is thus not more than per cent. to per cent. on the weight of fuel used. the gas we obtain contains, in a dry state, on an average, per cent. of carbonic acid, per cent. of carbonic oxide, per cent. of hydrogen, per cent. of hydrocarbons, and per cent. of nitrogen. the caloric value of this gas is very nearly equal to per cent. of the caloric value of the fuel used, but in using this gas for heating purposes, such as raising steam or making salt, we utilize the heat it can give very much better than in burning fuel, as we can completely burn it with almost the theoretical quantity of air, so that the products of combustion resulting do not contain more than to per cent. of free oxygen. consequently the heat escaping into the chimney is very much less than when fuel is burnt direct, and we arrive at evaporating, by means of the gas, per cent. of the water that we would evaporate by burning the fuel direct, in ordinary fireplaces. we have, however, to use a certain quantity of steam in the producers and in evaporating the sulphate of ammonia liquors, which has to be deducted from the steam that can be raised by the gas in order to get at the quantity of available steam therefrom obtainable. the former amounts, as already stated, to . ton, the latter to . ton of steam per ton of fuel burnt, making a total of . ton. the gas obtained from one ton of fuel evaporates . tons of water in good steam boilers, working at a rate of evaporation of to tons per hours under lb. pressure. deducting from this the . ton necessary for working the plant leaves an available amount of steam raised by the gas from one ton of fuel of . tons, equal to per cent. of the steam that we can obtain from the same fuel by hand firing. in addition to the gas, we obtain about per cent. of tar from the fuel. this tar is very thick, and of little commercial value. it contains only per cent. of oils volatile below ° c., and per cent. of oils of a higher boiling point, consisting mostly of creosote oils very similar to those obtained from blast furnaces; and only small quantities of anthracene and paraffin wax. i have made no attempts to utilize this tar except as fuel. it evaporates nearly twice as much water as its weight of coal, and we have thus to add its evaporative efficiency to that of the gas given above, leading to a total of about per cent. of the evaporative efficiency of the fuel used in the producers. the loss involved in gasifying the fuel to recover the ammonia therefrom amounts thus to per cent. of the fuel used. this means that, where we have now to burn tons of fuel, we shall have to burn tons in the producers in order to obtain ammonia equal to about half the nitrogen contained therein. our actual yield of ammonia on a large scale amounting on an average to kilos., equal to . lb. per ton of fuel, tons of fuel will turn out tons of sulphate of ammonia. we thus consume . tons of fuel for every ton of sulphate obtained, or nearly the same quantity as is used in producing a ton of caustic soda by the le blanc process--a product not more than half the value of ammonium sulphate. at present prices in northwich this fuel represents a value of s. if we add to this the extra cost of labor over and above the cost of burning fuel in ordinary fireplaces, the cost of sulphuric acid, bags, etc., we come to a total of l. s. to l. per ton of sulphate of ammonia, which at the present selling price of this article, say l. per ton, leaves, after a liberal allowance for wear and tear of plant, an ample margin of profit. with a rise in the price of fuel, this margin, however, rapidly decreases, and the working of the process will, of course, be much more expensive on a small scale, as will also be the cost of the plant, which under all circumstances is very considerable. the great advantages incidental to this process over and above the profit arising from the manufacture of sulphate of ammonia, viz., the absolute impossibility of producing smoke and the great regularity of the heating resulting from the use of gas, are, therefore, as far as i can see for the present, only available for large consumers of cheap fuel. we have tried many experiments to produce hydrochloric acid in the producers, with the hope of thereby increasing the yield of ammonia, as it is well known that ammonium chloride vapor, although it consists of a mixture of ammonia gas and hydrochloric acid gas, is not at all dissociated at temperatures at which the dissociation of ammonia alone has already taken place to a considerable extent. i had also hoped that i might in this way produce the acid necessary to combine with the ammonia at very small cost. for this purpose we moistened the fuel used with concentrated brine, and also with the waste liquors from the ammonia soda manufacture, consisting mainly of chloride of calcium; and we also introduced with the fuel balls made by mixing very concentrated chloride of calcium solution with clay, which allowed us to produce a larger quantity of hydrochloric acid in the producer than by the other methods. we did in this way succeed in producing hydrochloric acid sometimes less and sometimes more than was necessary to combine with the ammonia, but we did not succeed in producing with regularity the exact amount of acid necessary to neutralize the ammonia. when the ammonia was in excess, we had therefore to use sulphuric acid as before to absorb this excess, and we were never certain that sometimes the hydrochloric acid might not be in excess, which would have necessitated to construct the whole plant so that it could have resisted the action of weak hydrochloric acid--a difficulty which i have not ventured to attack. the yield of ammonia was not in any case increased by the presence of the hydrochloric acid. this explains itself if we consider that there is only a very small amount of ammonia and hydrochloric acid diffused through a very large volume of other gases, so that the very peculiar protective action which the hydrochloric acid does exercise in retarding the dissociation of ammonia in ammonium chloride vapor, where an atom of ammonia is always in contact with an atom of hydrochloric acid, will be diminished almost to zero in such a dilute gas where the atoms of hydrochloric acid and ammonia will only rarely come into immediate contact with each other. when we burnt coke by a mixture of air and steam in presence of a large excess of hydrochloric acid, the yield of ammonia certainly was thereby considerably increased, but such a large excess cannot be used on an industrial scale. i have therefore for the present to rest satisfied with obtaining only half the nitrogen contained in the fuel in the form of ammonia. the enormous consumption of fuel in this country--amounting to no less than million tons per annum--would at this rate yield as much as five million tons of sulphate of ammonia a year, so that if only one-tenth of this fuel would be treated by the process, england alone could supply the whole of the nitrogenous compounds, sulphate of ammonia, and nitrate of soda at present consumed by the old world. as the process is especially profitable for large consumers of fuel situated in districts where fuel is cheap, it seems to me particularly suitable to be adopted in this country. it promises to give england the privilege of supplying the old world with this all-important fertilizer, and while yielding a fair profit to the invested capital and finding employment for a considerable number of men, to make us, last not least, independent of the new world for our supply of so indispensable a commodity. before leaving my subject, i will, if you will allow me, give you in a few words a description of two other inventions which have been the outcome of this research. while looking one day at the beautiful, almost colorless, flame of the producer gas burning under one of our boilers, it occurred to me that a gas so rich in hydrogen might be turned to better use, and that it might be possible to convert it direct into electricity by means of a gas battery. you all know that lord justice grove showed, now fifty years ago, that two strips of platinum partly immersed in dilute sulphuric acid, one of which is in contact with hydrogen and the other with oxygen, produce electricity. i will not detain you with the many and varied forms of gas batteries which dr. carl langer (to whom i intrusted this investigation) has made and tried during the last four years, in order to arrive at the construction of a gas battery which would give a practical result, but i will call your attention to the battery before me on the table, which is the last result of our extended labors in this direction, and which we hope will mark a great step in advance in the economic production of electricity. the distinguishing feature of this battery is that the electrolyte is not employed as a mobile liquid, but in a quasi-solid form, and it is, therefore, named dry gas battery. it consists of a number of elements, which are formed of a porous diaphragm of a non-conducting material (in this instance plaster of paris), which is impregnated with dilute sulphuric acid. both sides of this diaphragm are covered with very fine platinum leaf perforated with very numerous small holes, and over this a thin film of platinum black. both these coatings are in contact with frameworks of lead and antimony, insulated one from the other, which conduct the electricity to the poles of the battery. a number of these elements are placed side by side, with non-conducting frames intervening, so as to form chambers through which the hydrogen gas is passed along one side of the element and air along the other. this peculiar construction allows us to get a very large amount of duty from a very small amount of platinum. one of the batteries before you, consisting of seven elements, with a total effective surface of half a square meter, contains ½ grammes of platinum leaf and grammes of platinum black, a total of ½ grammes of platinum, and produces a current of amperes and volts, or watts, when the outer resistance is properly adjusted. this current is equal to nearly per cent. of the total energy obtainable from the hydrogen absorbed in the battery. in order to maintain a constant current, we have from time to time (say once an hour) to interchange the gases, so as to counteract the disturbing influence produced by the transport of the sulphuric acid gas from one side of the diaphragm to the other. this operation can easily be performed automatically by a commutator worked by a clock. the water produced in the battery by the oxidation of the hydrogen is carried off by the inert gas mixed with the hydrogen, and by the air, of which we use a certain excess for this purpose. this is important, as if the platinum black becomes wet, it loses its absorbing power for the gases almost completely and stops the work of the battery. to avoid this was in fact the great difficulty in designing a powerful gas battery, and all previous constructions which employed the electrolyte as a mobile liquid failed in consequence. the results obtained by our battery are practically the same whether pure oxygen and hydrogen or air and gases containing per cent. of hydrogen are used; but we found that the latter gases must be practically free from carbonic oxide and hydrocarbons, which both interfere very much with the absorbing power of the platinum black. we had thus to find a cheap method of eliminating these two gases from the producer gas, and converting them at the same time into their equivalent of hydrogen. the processes hitherto known for this purpose, viz., passing a mixture of such gases with steam over lime (which i mentioned some time ago) or over oxide of iron or manganese, require high temperatures, which render them expensive, and the latter do not effect the reaction to a sufficient extent for our purpose. we have succeeded in attaining our object at a temperature below that at which the gases leave my producers, viz., at ° c. to ° c., by passing the producer gases, still containing a considerable excess of steam, over metallic nickel or cobalt. these metals have the extraordinary property of decomposing almost completely, even at the low temperature named, carbonic oxide into carbon and carbonic acid and hydrocarbons into carbon and hydrogen. in order to carry the process out with small quantities of nickel and cobalt, we impregnate pumice stone or similar material with a salt of nickel or cobalt, and reduce this by means of hydrogen or producer gas. these pieces of pumice stone are filled into a retort or chamber and the hot gases passed through them. as the reaction produces heat, it is not necessary to heat the chambers or retorts from the outside when the necessary temperature has once been attained. this process has not yet been carried out on a large scale, but the laboratory experiments have been so satisfactory that we have no doubt as to its complete success. it will enable us to obtain gases containing per cent. to per cent. of hydrogen and practically free from carbonic oxide and hydrocarbons from producer gas at a very small cost, and thus to make the latter suitable for the production of electricity by our gas battery. we obtain, as stated before, per cent. of the energy in the hydrogen absorbed in the battery in the form of electricity, while, if the same gas was consumed under steam boilers to make steam, which, as i have shown before, could in this way be raised cheaper than by burning fuel direct, and if this steam was turned into motive power by first-rate steam engines, and the motive power converted into electricity by a dynamo, the yield of electricity would in the most favorable case not exceed per cent. of the energy in the gas. i hope that this kind of battery will one day enable us to perform chemical operations by electricity on the largest scale, and to press this potent power into the service of the chemical industries. the statement is frequently made that "necessity is the mother of invention." if this has been the case in the past, i think it is no longer so in our days, since science has made us acquainted with the correlation of forces, teaching us what amount of energy we utilize and how much we waste in our various methods for attaining certain objects, and indicating to us where and in what direction and how far improvement is possible; and since the increase in our knowledge of the properties of matter enables us to form an opinion beforehand as to the substances we have available for obtaining a desired result. we can now foresee, in most cases, in what direction progress in technology will move, and in consequence the inventor is now frequently in advance of the wants of his time. he may even create new wants, to my mind a distinct step in the development of human culture. it can then no longer be stated that "necessity is the mother of invention;" but i think it may truly be said that the steady, methodical investigation of natural phenomena is the father of industrial progress. sir lowthian bell, bart., f.r.s., in moving a vote of thanks, said that the meeting had had the privilege of listening to a description of results obtained by a man of exceptional intelligence and learning, supplemented by that devotion of mind which qualified him to pursue his work with great energy and perseverance. the importance of the president's address could not possibly be overrated. at various periods different substances had been put forward as indications of the civilization of the people. he remembered hearing from dr. ure that he considered the consumption of sulphuric acid to be the most accurate measure of the civilization of the people. in course of time sulphuric acid gave way to soap, the consumption of which was probably still regarded as the great exponent of civilization by such of his fellow citizens as had thereby made their name. from what he had heard that morning, however, he should be inclined to make soap yield to ammonia, as sulphuric acid had in its time succumbed to soap. for not only was ammonia of great importance to us as a manufacturing nation, but it almost appeared to be a condition of our existence. england had a large population concentrated on an area so small as to make it almost a matter of apprehension whether the surface could maintain the people upon it. we were now importing almost as much food as we consumed, and were thus more and more dependent on the foreigner. under certain conditions this would become a very serious matter, and thus any one who showed how to produce plenty of ammonia at a cheap rate was a benefactor to his country. mr. mond's process seemed to come nearer to success than any which had preceded it, and it needed no words from him to induce the meeting to accord a hearty vote of thanks to the president for his admirable paper. mr. j. c. stevenson, m.p., in seconding the motion, said that no paper could be more interesting and valuable to the society than that delivered by the president. it opened out a future for the advancement of chemical industry which almost overcame one by the greatness of its possibilities. mr. mond had performed an invaluable service by investigating the various methods proposed for the manufacture of ammonia, and clearing the decks of those processes supposed by their inventors to be valuable, but proved by him to be delusive. it gave him hearty pleasure therefore to second the vote of thanks proposed by sir lowthian bell. the vote having been put and carried by acclamation, after a brief reply from the president: the secretary read the report of the scrutators, which showed that ballot papers had been sent in, voting for the proposed list intact, and four substituting other names. the gentlemen nominated in the list issued by the council were therefore declared elected. * * * * * in his brief report for the year ending may , , the director of the pasteur institute, paris, announces the treatment of , subjects, of whom were seized with rabies during and within a fortnight after the process. but only succumbed after the treatment had been completely carried out, making death in , or, including all cases, in . * * * * * alkali manufactories. when the alkali, etc., works regulation act was passed in , it was supposed that the result would be that the atmosphere in the districts where such works are situated would be considerably improved, and, consequently, that vegetation would have a better chance in the struggle for existence, and the sanitary conditions of human dwellings would be advanced. in all these respects the act has been a success. but perhaps the most notable result is the effect which the act and those which have preceded it have had upon the manufactures which they control. this was not anticipated by manufacturers, but now one of the principal of them (mr. a. m. chance) has stated that "government inspection has not only led to material improvement in the general management of chemical works, but it has also been in reality a distinct benefit to, rather than a tax upon, the owners of such works." this expression of opinion is substantiated by the chief inspector under the act, whose report for last year has recently been laid before the local government board. there are , works in the united kingdom which are visited by the inspectors, and in only two of these during did the neglect to carry out the inspectors' warnings become so flagrant as to call for legal interference; viz., in the case of thomas farmer & co. (limited), victoria docks, e., who were fined l. and costs for failing to use the "best practicable means" for preventing the escape of acid gas from manure plant; and in the case of joseph fison & co., bramford, who were fined l. and costs for excessive escape of acid gas from sulphuric acid plant. there were seven other cases, but these were simply for failure to register under the act. it is very evident, therefore, that from a public point of view the act is splendidly successful, and from the practical or scientific side it is no less satisfactory. of the total number of chemical works ( , ) are registered in england, in scotland, and in ireland--a decrease in the case of scotland of , and in ireland of from the previous year, while england has increased by . this must not, however, be taken as a sign of diminished production, because there is a tendency for the larger works to increase in size and for the smaller ones to close their operations. the principal nuisances which the inspectors have to prevent are the escape of hydrochloric acid gas from alkali works and of sulphurous gas from vitriol and manure works. the alkali act forbids the manufacturer to allow the escape of more than per cent. of the hydrochloric acid which he produces, or that that acid must not exist to a greater extent than . grain in cubic foot of air, steam, or chimney gas which accompanies. the inspectors' figures for last year show that the percentage of the acid which escaped amounted to only . of the total produced, which is equal to . grain per cubic foot, and much below the figures for previous years. the figures in regard to sulphurous gas are equally satisfactory. the act allows grains of sulphuric anhydride (so ) per cubic foot to escape into the air, and last year's average was only . grain, or less than a fifth of the limit. of course it is now the aim of the leblanc alkali manufacturers to reduce the escape of hydrochloric acid to the lowest possible amount, as their profits depend solely upon the sale of chlorine products, soda products being sold at a loss. in this connection it is interesting to note that the amount of common salt manufactured in the united kingdom in was , , tons, and of this nearly , tons were taken by leblanc soda makers, and over , tons by the ammonia-soda makers. the figures are very largely in excess of previous years, and indicate a gratifying growth in trade. the salt used in the leblanc process yields the hydrochloric acid, and that in the ammonia-soda method none, so that we may put down the theoretical production of acid as , tons, , tons of which was allowed to escape. what was a mere trace in the chimney gases amounts, therefore, to a good round figure at the end of a year, and if it were converted into bleaching powder it would be worth nearly , l. these figures are, it should be understood, based on theory, but they serve to show to what importance a gas has now reached which twenty-five years ago was a perfect incubus to the manufacturers, and wrought desolation in the country sides miles and miles around the producing works. there has long been an expectation that the ammonia-soda makers would add the manufacture of bleaching powder to their process, but they appear to be as far as ever from that result, and meanwhile the leblanc makers are honestly striving to utilize every atom of the valuable material which they handle. hence the eagerness to recover the sulphur from tank waste by one or other of the few workable processes which have been proposed. this waste contains from to per cent. of sulphur, and when it is stated that the total amount of tank waste produced yearly is about , tons, containing about , tons of sulphur, it will be seen how large is the reward held out to the successful manipulator. moreover, the value of the sulphur that might possibly be saved is not the only prize held out to those who can successfully deal with the waste, for this material is not only thrown away as useless, but much expense is incurred in the throwing. in lancashire and in other inland districts land must be found on which to deposit it, and the act of depositing is costly, for unless it is beaten together so as to exclude the air, an intolerable nuisance arises from it. the cost of haulage and deposit on land varies, according to the district, from s. to s. d. a ton. in widnes it is about s. in the newcastle district the practice is to carry this material out to sea at a cost of about d. a ton. mr. chance's process for the recovery of sulphur from the waste signalizes the centenary of the leblanc process; parnell and simpson are following in his wake, and lately mr. f. gossage, of widnes, has been working on a process for the production of alkali, which enables him to save the sulphur of the sulphuric acid. in his process a mixture of parts leblanc salt cake (sulphate of soda) and parts common salt is mixed with coal and heated in a furnace, and so reduced to sulphide of sodium. the resulting "ash" is then dissolved in water and exposed to the action of carbonic acid, when sulphureted hydrogen is given off, to be dealt with as in mr. chance's sulphur process, while bicarbonate of soda is formed and separates by precipitation from the solution of undecomposed common salt. ere long it is expected this new method will be in active operation in some leblanc works, the plant of which will, in all probability, be utilized. it has these great advantages: the absence of lime, the recovery of the sulphur used in the first instance and the consequent absence of the objectionable tank waste. thus a bright promise is held out that the days of alkali waste are numbered, and that the air in certain parts of lancashire will be more balmy than it has been in the memory of the oldest inhabitant.--_chemist and druggist._ * * * * * the fuels of the future. it is undeniable that in this country, at least, we are accustomed to regard coal as the chief, and, indeed, the only substance which falls to be considered under the name of fuel. in other countries, however, the case is different. various materials, ranging from wood to oil, come within the category of material for the production of heat. the question of fuel, it may be remarked, has a social, an antiquarian, and a chemical interest. in the first place, the inquiry whether or not our supplies of coal will hold out for say the next hundred thousand years, or for a much more limited period only, has been very often discussed by sociologists and by geological authorities. again, it is clear that as man advances in the practice of civilized arts, his dependence upon fuel becomes of more and more intimate character. he not merely demands fire wherewith to cook his food, and to raise his own temperature or that of his dwelling, but requires fuel for the thousand and one manufacturing operations in which he is perpetually engaged. it is obvious that without fuel civilized life would practically come to an end. we cannot take the shortest journey by rail or steamboat without a tacit dependence upon a fuel supply; and the failure of this supply would therefore mean and imply the extinction of all the comforts and conveniences on which we are accustomed to rely as aids to easy living in these latter days. again, socially regarded, man is the only animal that practices the fire-making habit. even the highest apes, who will sit round the fire which a traveler has just left, and enjoy the heat, do not appear to have developed any sense or idea of keeping up the fire by casting fresh fuel upon it. it seems fairly certain, then, that we may define man as being a "fuel-employing animal," and in so doing be within the bounds of certitude. he may be, and often is, approached by other animals in respect of many of his arts and practices. birds weave nest materials, ants make--and maul--slaves, beavers build dams, and other animals show the germs and beginnings of human contrivances for aiding the processes of life, but as yet no animal save man lights and maintains a fire. that the fire-making habit must have dawned very early in human history appears to be proved by the finding of ashes and other evidences of the presence of fire among the remains and traces of primitive man. all we know, also, concerning the history of savage tribes teaches us that humanity is skillful, even in very rude stages of its progress, in the making of fire. the contrivances for obtaining fire are many and curious in savage life, while, once attained, this art seems to have not only formed a constant accompaniment but probably also a determining cause in the evolution of civilization. wood, the fat of animals, and even the oils expressed from plants, probably all became known to man as convenient sources of fuel in prehistoric times. from the incineration of wood to the use of peat and coal would prove an easy stage in the advance toward present day practices, and with the attainment of coal as a fuel the first great era in man's fire-making habits may be said to end. beyond the coal stage, however, lies the more or less distinctively modern one of the utilization of gas and oil for fuel. the existence of great natural centers, or underground stores, of gas and oil is probably no new fact. we read in the histories of classic chroniclers of the blazing gases which were wont to issue from the earth, and to inspire feelings of superstitious awe in the minds of beholders. only within a few years, however, have geologists been able to tell us much or anything regarding these reservoirs of natural fuel which have become famous in america and in the russian province of baku. for example, it is now known that three products--gas, oil, and salt or brine--lie within natural receptacles formed by the rock strata in the order of their weight. this law, as has well been said, forms the foundation of all successful boring experiments, and the search for natural fuel, therefore, becomes as easy and as reliable a duty as that for artesian water or for coal. the great oil fever of the west was attended at first, as professor m'gee tells us, with much waste of the product. wells were sunk everywhere, and the oil overflowed the land, tainting the rivers, poisoning the air, and often driving out the prospectors from the field of discovery. in baku accidents and catastrophes have, similarly, been of frequent occurrence. we read of petroleum flowing from the ground in jets feet high, and as thick as a man's body; we learn how it swept away the huge cranes and other machinery, and how, as it flowed away from the orifices, its course was marked by the formation of rivers of oil many miles in length. in america the pressure of rock gas has burst open stills weighing over a ton, and has rushed through huge iron tanks and split open the pipes wherewith it was sought to control its progress. the roar of this great stream of natural gas was heard for miles around as it escaped from the outlet, and when it was ignited the pillar of flame illumined the surrounding country over a radius extending in some cases to forty miles. it is clear that man having tapped the earth's stores of natural fuel, stood in danger of having unloosed a monster whose power he seemed unable to control. yet, as the sequel will show, science has been able to tackle with success the problems of mastering the force and of utilizing the energy which are thus locked up within the crust of the globe. as regards the chemistry of rock gas, we may remark in the first place that this natural product ranks usually as light carbureted hydrogen gas. in this respect it is not unlike the marsh gas with which everyone is familiar, which is found bubbling up from swamps and morasses, and which constitutes the "will o' the wisp" of romance. in rock gas, marsh gas itself is actually found in the proportion of about per cent. the composition of marsh gas is very simple. it consists of the two elements carbon and hydrogen united in certain proportions, indicated chemically by the symbol ch . we find, in fact, that rock gas possesses a close relationship, chemically speaking, with many familiar carbon compounds, and of these latter, petroleum itself, asphaltum, coal, jet, graphite or plumbago, and even the diamond itself--which is only crystallized carbon after all--are excellent examples. the differences between these substances really consist in the degree of fixing of the carbon or solid portion of the product, as it were, which exists. thus in coal and jet the carbon is of stable character, such as we might expect to result from the slow decomposition of vegetable matter, and the products of this action are not volatile or liable to be suddenly dissociated or broken up. on the other hand, when we deal with the _hydrocarbons_ as they are called, in the shape of rock gas, naphtha, petroleum, tar, asphaltum, and similar substances, we see how the carbon has become subordinated to the hydrogen part of the compounds, with the result of rendering them more or less unstable in their character. as professor m'gee has shown us, there is in truth a graduated series leading us from the marsh gas and rock gas as the lightest members of this class of compounds onward through the semi-gaseous naphtha to the fluid petroleum, the semi-fluid tar, the solid asphaltum, and the rigid and brittle substance known as albertite, with other and allied products. having said so much regarding the chemistry of the fuels of the future, we may now pass to consider their geological record. a somewhat curious distribution awaits the man of science in this latter respect. most readers are aware that the geologists are accustomed to classify rocks, according to their relative age, into three great groups, known respectively as the primary, secondary, and tertiary periods. in the secondary period we do not appear to meet with the fuels of the future, but as far back as the devonian or old red sandstone period, and in the still older silurian rocks, stores of gas and petroleum abound. in the latest or tertiary period, again, we come upon nearly all the forms of fuels we have already specified. the meaning of this geological distribution of the fuels is entirely fortuitous. dr. m'gee tells us that as their formation depended on local conditions (such as plant growth), and as we have no means of judging why such local conditions occurred within any given area, so must we regard the existence of fuel products in particular regions as beyond explanation. of one point, however, we are well assured, namely that the volume of the fuels of the future is developed in an inverse proportion to their geological age. the proportionate volume, as it has been expressed, diminishes progressively as the geological scale is descended. again, the weight of the fuels varies directly with their age; for it is in the older formation of any series that we come upon the oils and tars and asphaltum, while the marsh gas exists in later and more recently formed deposits. further geological research shows us that the american gas fields exist each as an inverted trough or dome, a conformation due, of course, to the bending and twisting of the rocks by the great underground heat forces of the world. the porous part of the dome may be sandstone or limestone, and above this portion lie shales, which are the opposite of porous in texture. the dome, further, contains gas above, naphtha in the middle, and petroleum below, while last of all comes water, which is usually very salt. in the indiana field, however, we are told that the oils lie near the springing or foundation of the arch of the dome, and at its crown gas exists, and overlies brine. a very important inquiry, in relation to the statement that upon the products whose composition and history have just been described the fuel supply of the future will depend, consists in the question of the extent and duration of these natural gas and oil reservoirs. if we are beginning to look forward to a time when our coal supply will have been worked out, it behooves us to ask whether or not the supply of natural gas and oil is practically illimitable. the geologist will be able to give the coming man some degree of comfort on this point, by informing him that there seems to be no limit to the formation of the fuel of the future. natural gas is being manufactured to-day by nature on a big scale. wherever plant material has been entombed in the rock formations, and wherever its decomposition proceeds, as proceed it must, there natural gas is being made. so that with the prospect of coal becoming as rare as the dodo itself, the world, we are told by scientists, may still regard with complacency the failure of our ordinary carbon supply. the natural gases and oils of the world will provide the human race with combustible material for untold ages--such at least is the opinion of those who are best informed on the subject. for one thing, we are reminded that gas is found to be the most convenient and most economical of fuels. rock gas is being utilized abroad even now in manufacturing processes. dr. m'gee says that even if the natural supply of rock gas were exhausted to-morrow, manufacturers of glass, certain grades of iron, and other products would substitute an artificial gas for the natural product rather than return to coal. he adds that "enormous waste would thereby be prevented, the gas by which the air of whole counties in coke-burning regions is contaminated would be utilized, and the carbon of the dense smoke clouds by which manufacturing cities are overshadowed would be turned to good account." so that, as regards the latter point, even mr. ruskin with his horror of the black smoke of to-day and of the disfigurement of sky and air might become a warm ally of the fuel of the future. the chemist in his laudation of rock gas and allied products is only re-echoing, when all is said and done, the modern eulogy pronounced on ordinary coal gas as a cooking and heating medium. we are within the mark when we say that the past five years alone have witnessed a wonderful extension in the use of gas in the kitchen and elsewhere. it would be singular, indeed, if we should happen to be already anticipating the fuel of the future by such a practice. whether or not this is the case, it is at least satisfactory for mankind to know that the mother earth will not fail him when he comes to demand a substitute for coal. i may be too early even to think of the day of extinction; but we may regard that evil day with complacency in face of the stores of fuel husbanded for us within the rock foundations of our planet.--_glasgow herald._ * * * * * portable electric light. the famous house of mm. sautter, lemonnier & co. takes a conspicuous part in the paris exhibition, and from the wide range of its specialties exhibits largely in three important branches of industry: mechanics, electricity, and the optics of lighthouses and projectors. in these three branches mm. sautter, lemonnier & co. occupy a leading position in all parts of the world. the invention of the aplanetic projector, due to col. mangin, was a clever means of overcoming difficulties, practically insurmountable, that were inseparable from the construction of parabolic mirrors; this contributed chiefly to the success of mm. sautter, lemonnier & co. in this direction. the firm has produced more than , of these apparatus, representing a value of nearly £ , , for the french and other governments. besides the great projector, which forms the central and crowning object of the exhibit of mm. sautter, lemonnier & co. in the machinery hall, the firm exhibits a projector centimeters in diameter mounted on a crane traveling on wheels, in the pavilion of the war department. the lamp used for this apparatus has a luminous value of , carcels, with a current of amperes; the amplifying power of the mirror is , , which gives an intensity of ten millions to twelve millions of carcels to the beam. projectors used for field work are mounted on a portable carriage, which also contains the electric generator and the motor driving it. [illustration: military portable electric light at the paris exhibition.] it consists of a tubular boiler (dion, bouton & trepardoux system). this generator is easily taken to pieces, cleaned, and repaired, and steam can be raised to working pressure in minutes. the mechanical and electrical part of the apparatus consists of a parsons turbo-motor, of which mm. sautter, lemonnier & co. possess the license in france for application to military and naval purposes. the speed of the motor is , revolutions per minute, and the dynamo is driven direct from it; at this speed it gives a current of amperes with and from to volts; the intensity of the light is from , to , carcels. the carriage upon which the whole of this apparatus is mounted is carried on four wheels, made of wood with gun metal mountings. these are more easy to repair when in service than if they were wholly of iron. the weight of the carriage is three tons.--_engineering._ * * * * * electric motor for alternating currents. prof. galileo ferraris, of turin, who has carefully studied alternating currents and secondary transformers, has constructed a little motor based upon an entirely new principle, which is as follows: if we take two inductive fields developed by two bobbins, the axes of which cut each other at right angles, and a pole placed at the vertex of the angle, this pole will be subjected to the simultaneous action of the two bobbins, and the resultant of the magnetic actions will be represented in magnitude and direction by the diagonal of the parallelogram, two consecutive sides of which have for their length the intensity of the two fields, and for their direction the axes of the two bobbins. if into each of these bobbins we send alternating currents having between one bobbin and the other a difference of phase of °, the extremity of the resultant will describe a circle having for its center the vertex of the right angle. if, instead of a fixed pole, we use a metal cylinder movable on its axis, we shall obtain a continuous rotatory motion of this part, and the direction of the movement will change when we interchange the difference of phase in the exciting currents. this rotatory movement is not due to the foucault currents, for the metal cylinder may consist of plates of iron insulated from each other. in order to realize the production of these fields, several means can be employed: the current is sent from an alternating current machine into the primary circuit of a transformer and thence into one of the bobbins, the other being supplied by means of the secondary current of the transformer. a resistance introduced into the circuit will produce the required difference of phase, and the equality of the intensities of the fields will be obtained by multiplying the number of turns of the secondary wire on the bobbin. moreover, the two bobbins may be supplied by the secondary current of a transformer by producing the difference of phase, as in the first case. in the motor constructed by prof. ferraris the armature consisted of a copper cylinder measuring centimeters in diameter and centimeters in length, movable on its axis. the inductors were formed of two groups of two bobbins. the bobbins which branched off from the primary circuit of a gaulard transformer, and were connected in series, comprised spirals with a resistance of ohms; the bobbins comprising the secondary circuit were coupled in parallel, and had spirals with . ohms resistance. in order to produce the difference of phase, a resistance of ohms was introduced into the second circuit, when the dynamo produced a current of amperes with inversions per second. under these conditions the available work measured on the axis of the motor was found for different speeds: revolutions per minute: -- -- -- -- -- . watts measured at the brake: . -- . -- . -- . -- . -- . . the maximum rendering corresponds to a speed of rotation of revolutions, and prof. ferraris attributes the loss of work for higher speeds to the vibrations to which the machine is exposed. at present the apparatus is but a laboratory one.--_bulletin international de l'electricite._ * * * * * the electric age. by charles carleton coffin. the application of electricity for our convenience and comfort is one of the marvels of the age. never in the history of the world has there been so rapid a development of an occult science. prior to very little was known in regard to magnetism and electricity. during that year oersted discovered that an electric current would deflect a magnetic needle, thus showing that there was some relationship between electric and magnetic force. a few months later, arago and sir humphry davy, independently of each other, discovered that by coiling a wire around a piece of iron, and passing an electric current through it, the iron would possess for the time being all the properties of a magnet. in william sturgeon, of london, bent a piece of wire in the form of the letter u, wound a second wire around it, and, upon connecting it with a galvanic battery, discovered that the first wire became magnetic, but lost its magnetic property the moment the battery was disconnected. the idea of a telegraphic signal came to him, but the electric impulse, through his rude apparatus, faded out at a distance of fifty feet. in prof. joseph henry, of this country, constructed a line of wire, one and a half miles in length, and sent a current of electricity through it, ringing a bell at the farther end. the following year professor faraday discovered magnetic induction. this, in brief, is the genesis of magnetic electricity, which is the basis of all that has been accomplished in electrical science. the first advance after these discoveries was in the development of the electric telegraph--the discovery in , by the philosopher steinhill, that the earth could serve as a conductor, thus requiring but one wire in the employment of an electric current. simultaneously came morse's invention of the mechanism for the telegraph in , foreshadowed by henry in the ringing of bells, thus transmitting intelligence by sound. four years later, in , prof. m. g. farmer, still living in eliot, me., attached an electro-magnet to clockwork for the striking of bells to give an alarm of fire. the same idea came to william f. channing. the mechanism, constructed simply to illustrate the idea by professor farmer, was placed upon the roof of the court house in boston, and connected with the telegraph wire leading to new york, and an alarm rung by the operator in that city. the application of electricity for giving definite information to firemen was first made in boston, and it was my privilege to give the first alarm on the afternoon of april , . at the close of the last century, benjamin thompson, born in woburn, mass., known to the world as count rumford, was in the workshop of the military arsenal of the king of bavaria in munich, superintending the boring of a cannon. the machinery was worked by two horses. he was surprised at the amount of heat which was generated, for when he threw the borings into a tumbler filled with cold water, it was set to boiling, greatly to the astonishment of the workmen. whence came the heat? what was heat? the old philosopher said that it was an element. by experiment he discovered that a horse working two hours and twenty minutes with the boring machinery would heat nineteen pounds of water to the boiling point. he traced the heat to the horse, but with all his acumen he did not go on with the induction to the hay and oats, to the earth, the sunshine and rain, and so get back to the sun. one hundred years ago there was no chemical science worthy of the name, no knowledge of the constitution of plants or the properties of light and heat. the old philosophers considered light and heat to be fluids, which passed out of substances when they were too full. count rumford showed that motion was convertible into heat, but did not trace the motion to its source, so far as we know, in the sun. it is only forty-six years since professor joule first demonstrated the mutual relations of all the manifestations of nature's energy. thirty-nine years only have passed since he announced the great law of the convertibility of force. he constructed a miniature churn which held one pound of water, and connected the revolving paddle of the churn with a wheel moved by a pound weight, wound up the weight, and set the paddle in motion. a thermometer detected the change of temperature and a graduated scale marked the distance traversed by the descending weight. repeated experiments showed that a pound weight falling feet would raise the temperature of water one degree, and that this was an unvarying law. this was transferring gravitation to heat, and the law held good when applied to electricity, magnetism, and chemical affinity, leading to the conclusion that they were severally manifestations of one universal power.--_congregationalist._ * * * * * early electric lighting. the opening of the new station of the electric lighting co., of salem, mass., was recently celebrated with appropriate festivities. among the letters of regret from those unable to attend the opening was the following from prof. moses g. farmer: "eliot, me., aug. , . "_to the salem electric lighting company, charles h. price, president_: "gentlemen: it would give me great pleasure to accept your kind invitation to be present at the opening of your new station in salem on the th of this present august. "it is now thirty years since the first dwelling house in salem was lighted by electricity. that little obscure dwelling, pearl street, formerly owned by 'pa' webb, had the honor to be illuminated by the effulgent electric beam during every evening of july, , as some of your honored residents, perhaps, well remember. mr. george d. phippen can doubtless testify to one or more evenings; mr. wm. h. mendell, of boston, can also add his testimony; dozens of others could also do the same, had not some of them already passed to the 'great beyond,' among whom i well recollect the interest taken by the late and honored henry l. williams, mr. j. g. felt, and i do not know how many others. i well remember reading some of the very finest print standing with my back to the front wall and reading by the light of a candle power lamp on the northernmost end of the mantel piece in the parlor; very possibly the hole in which the lamp was fastened remains to this day. in a little closet in the rear sleeping room was a switch which could be turned in one direction and give a beautiful glow light, while if turned in the other direction, it instantly gave as beautiful a dark. my then year old daughter used to surprise and please her visitors by suddenly turning on and off the 'glim.' it is not well to despise the day of small things, for although the dynamo had not at that date put in an appearance, and though i used thirty-six smee cells of six gallons capacity each, yet i demonstrated then and there that the incandescent electric light was a possibility, and although i innocently remarked to the late samuel w. bates, of boston, who with his partner, mr. chauncey smith, furnished so generously in the interest of science, not wholly without hope of return, the funds for the experiment, that it 'did not take much zinc,' and though mr. bates as naively replied, 'i notice that it takes some silver, though,' still it was then and there heralded as the coming grand illuminant for the dwelling. i am thankful to have lived to see my predictions partly fulfilled. "during the early fifties i published a statement something like this: 'one pound of coal will furnish gas enough to maintain a candle light for fifteen hours. one pound of gas (the product of five pounds of coal) will, in a good fishtail gas burner, furnish one candle light for seventy-five hours. one pound of coal burned in a good furnace, under a good boiler, driving a good steam engine, turning a good magneto-electric machine, will give a candle light for one thousand hours. but if all the energy locked up in one pound of pure carbon could be wholly converted into light, it would maintain one candle light for more than one and a half years.' "so, gentlemen, _nil desperandum_; there is still room for improvement. let your motto be 'excelsior.' possibly you may have already extracted from one-fifteenth to one-twelfth of the energy stored in the pound of carbon, but hardly more. go on, go on, and bring it so cheap as to reach the humblest dwelling when you shall celebrate the centennial of the opening of your new station. "i do most sincerely regret that i cannot be with you in the flesh. i am, like ixion of old, confined to a wheel (chair in my case), cannot walk, cannot even stand; hence, owing to the impairment of my understanding (???), i must wish you all the enjoyments of the evening, and gladly content myself that you have made so much possible. "very truly yours, moses g. farmer." * * * * * the modern theory of light.[ ] [footnote : being the general substance of a lecture to the ashmolean society in the university of oxford, on monday, june , . [reprinted from the _liverpool university college magazine_.]] by prof. oliver lodge. to persons occupied in other branches of learning, and not directly engaged in the study of physical science, some rumor must probably have traveled of the stir and activity manifest at the present time among the votaries of that department of knowledge. it may serve a useful purpose if i try and explain to outsiders what this stir is mainly about, and why it exists. there is a proximate and there is an ultimate cause. the proximate cause is certain experiments exhibiting in a marked and easily recognizable way the already theoretically predicted connection between electricity and light. the ultimate cause is that we begin to feel inklings and foretastes of theories, wider than that of gravitation, more fundamental than any theories which have yet been advanced; theories which if successfully worked out will carry the banner of physical science far into the dark continent of metaphysics, and will illuminate with a clear philosophy much that is at present only dimly guessed. more explicitly, we begin to perceive chinks of insight into the natures of electricity, of ether, of elasticity, and even of matter itself. we begin to have a kinetic theory of the physical universe. we are living, not in a newtonian, but at the beginning of a perhaps still greater thomsonian era. greater, not because any one man is probably greater than newton,[ ] but because of the stupendousness of the problems now waiting to be solved. there are a dozen men of great magnitude, either now living or but recently deceased, to whom what we now know toward these generalizations is in some measure due, and the epoch of complete development may hardly be seen by those now alive. it is proverbially rash to attempt prediction, but it seems to me that it may well take a period of fifty years for these great strides to be fully accomplished. if it does, and if progress goes on at anything like its present rate, the aspect of physical science bequeathed to the latter half of the twentieth century will indeed excite admiration, and when the populace are sufficiently educated to appreciate it, will form a worthy theme for poetry, for oratorios, and for great works of art. [footnote : though, indeed, a century hence it may be premature to offer an opinion on such a point.] to attempt to give any idea of the drift of progress in all the directions which i have hastily mentioned, to attempt to explain the beginnings of the theories of elasticity and of matter, would take too long, and might only result in confusion. i will limit myself chiefly to giving some notion of what we have gained in knowledge concerning electricity, ether, and light. even that is far too much. i find i must confine myself principally to light, and only treat of the others as incidental to that. for now well nigh a century we have had a wave theory of light; and a wave theory of light is quite certainly true. it is directly demonstrable that light consists of waves of some kind or other, and that these waves travel at a certain well-known velocity, seven times the circumference of the earth per second, taking eight minutes on the journey from the sun to the earth. this propagation in time of an undulatory disturbance necessarily involves a medium. if waves setting out from the sun exist in space eight minutes before striking our eyes, there must necessarily be in space some medium in which they exist and which conveys them. waves we cannot have unless they be waves in something. no ordinary medium is competent to transmit waves at anything like the speed of light; hence the luminiferous medium must be a special kind of substance, and it is called the ether. the _luminiferous_ ether it used to be called, because the conveyance of light was all it was then known to be capable of; but now that it is known to do a variety of other things also, the qualifying adjective may be dropped. wave motion in ether, light certainly is; but what does one mean by the term wave? the popular notion is, i suppose, of something heaving up and down, or, perhaps, of something breaking on the shore in which it is possible to bathe. but if you ask a mathematician what he means by a wave, he will probably reply that the simplest wave is y = a sin (p t - n x), and he might possibly refuse to give any other answer. and in refusing to give any other answer than this, or its equivalent in ordinary words, he is entirely justified; that is what is meant by the term wave, and nothing less general would be all-inclusive. translated into ordinary english the phrase signifies "a disturbance periodic both in space and time." anything thus doubly periodic is a wave; and all waves, whether in air as sound waves, or in ether as light waves, or on the surface of water as ocean waves, are comprehended in the definition. what properties are essential to a medium capable of transmitting wave motion? roughly we may say two--_elasticity_ and _inertia_. elasticity in some form, or some equivalent of it, in order to be able to store up energy and effect recoil; inertia, in order to enable the disturbed substance to overshoot the mark and oscillate beyond its place of equilibrium to and fro. any medium possessing these two properties can transmit waves, and unless a medium possesses these properties in some form or other, or some equivalent for them, it may be said with moderate security to be incompetent to transmit waves. but if we make this latter statement, one must be prepared to extend to the terms elasticity and inertia their very largest and broadest signification, so as to include any possible kind of restoring force and any possible kind of persistence of motion respectively. these matters may be illustrated in many ways, but perhaps a simple loaded lath or spring in a vise will serve well enough. pull aside one end, and its elasticity tends to make it recoil; let it go, and its inertia causes it to overshoot its normal position; both causes together cause it to swing to and fro till its energy is exhausted. a regular series of such springs at equal intervals in space, set going at regular intervals of time one after the other, gives you at once a wave motion and appearance which the most casual observer must recognize as such. a series of pendulums will do just as well. any wave-transmitting medium must similarly possess some form of elasticity and of inertia. but now proceed to ask what is this ether which in the case of light is thus vibrating? what corresponds to the elastic displacement and recoil of the spring or pendulum? what corresponds to the inertia whereby it overshoots its mark? do we know these properties in the ether in any other way? the answer, given first by clerk maxwell, and now reiterated and insisted on by experiments performed in every important laboratory in the world, is: the elastic displacement corresponds to electrostatic charge (roughly speaking, to electricity). the inertia corresponds to magnetism. this is the basis of the modern electro-magnetic theory of light. now let me illustrate electrically how this can be. the old and familiar operation of charging a leyden jar--the storing up of energy in a strained dielectric, any electrostatic charging whatever--is quite analogous to the drawing aside of our flexible spring. it is making use of the elasticity of the ether to produce a tendency to recoil. letting go the spring is analogous to permitting a discharge of the jar--permitting the strained dielectric to recover itself, the electrostatic disturbance to subside. in nearly all the experiments of electrostatics, ethereal elasticity is manifest. next consider inertia. how would one illustrate the fact that water, for instance, possesses inertia--the power of persisting in motion against obstacles--the power of possessing kinetic energy? the most direct way would be to take a stream of water and try suddenly to stop it. open a water tap freely and then suddenly shut it. the impetus or momentum of the stopped water makes itself manifest by a violent shock to the pipe, with which everybody must be familiar. the momentum of water is utilized by engineers in the "water ram." a precisely analogous experiment in electricity is what faraday called "the extra current." send a current through a coil of wire round a piece of iron, or take any other arrangement for developing powerful magnetism, and then suddenly stop the current by breaking the circuit. a violent flash occurs if the stoppage is sudden enough, a flash which means the bursting of the insulating air partition by the accumulated electro-magnetic momentum. briefly, we may say that nearly all electro-magnetic experiments illustrate the fact of ethereal inertia. now return to consider what happens when a charged conductor (say a leyden jar) is discharged. the recoil of the strained dielectric causes a current, the inertia of this current causes it to overshoot the mark, and for an instant the charge of the jar is reversed; the current now flows backward and charges the jar up as at first; back again flows the current, and so on, charging and reversing the charge with rapid oscillations until the energy is all dissipated into heat. the operation is precisely analogous to the release of a strained spring or to the plucking of a stretched string. but the discharging body thus thrown into strong electrical vibration is embedded in the all-pervading ether, and we have just seen that the ether possesses the two properties requisite for the generation and transmission of waves--viz., elasticity and inertia or density; hence, just as a tuning fork vibrating in air excites aerial waves or sound, so a discharging leyden jar in ether excites ethereal waves or light. ethereal waves can therefore be actually produced by direct electrical means. i discharge here a jar, and the room is for an instant filled with light. with light, i say, though you can see nothing. you can see and hear the spark indeed--but that is a mere secondary disturbance we can for the present ignore--i do not mean any secondary disturbance. i mean the true ethereal waves emitted by the electric oscillation going on in the neighborhood of this recoiling dielectric. you pull aside the prong of a tuning fork and let it go; vibration follows and sound is produced. you charge a leyden jar and let it discharge; vibration follows and light is excited. it is light just as good as any other light. it travels at the same pace, it is reflected and refracted according to the same laws; every experiment known to optics can be performed with this ethereal radiation electrically produced, and yet you cannot see it. why not? for no fault of the light; the fault (if there be a fault) is in the eye. the retina is incompetent to respond to these vibrations--they are too slow. the vibrations set up when this large jar is discharged are from a hundred thousand to a million per second, but that is too slow for the retina. it responds only to vibrations between , billions and , billions per second. the vibrations are too quick for the ear, which responds only to vibrations between and , per second. between the highest audible and the lowest visible vibrations there has been hitherto a great gap, which these electric oscillations go far to fill up. there has been a great gap simply because we have no intermediate sense organ to detect rates of vibration between , and , , , , , per second. it was, therefore, an unexplored territory. waves have been there all the time in any quantity, but we have not thought about them nor attended to them. it happens that i have myself succeeded in getting electric oscillations so slow as to be audible. the lowest i have got at present are per second, and for some way above this the sparks emit a musical note; but no one has yet succeeded in directly making electric oscillations which are visible, though indirectly every one does it when they light a candle. here, however, is an electric oscillator, which vibrates million times a second, and emits ethereal waves a yard long. the whole range of vibrations between musical tones and some thousand million per second is now filled up. these electro-magnetic waves have long been known on the side of theory, but interest in them has been immensely quickened by the discovery of a receiver or detector for them. the great though simple discovery by hertz of an "electric eye," as sir w. thomson calls it, makes experiments on these waves for the first time easy or even possible. we have now a sort of artificial sense organ for their appreciation--an electric arrangement which can virtually "see" these intermediate rates of vibration. the hertz receiver is the simplest thing in the world--nothing but a bit of wire or a pair of bits of wire adjusted so that when immersed in strong electric radiation they give minute sparks across a microscopic air gap. the receiver i have here is adapted for the yard-long waves emitted from this small oscillator; but for the far longer waves emitted by a discharging leyden jar an excellent receiver is a gilt wall paper or other interrupted metallic surface. the waves falling upon the metallic surface are reflected, and in the act of reflection excite electric currents, which cause sparks. similarly, gigantic solar waves may produce auroræ; and minute waves from a candle do electrically disturb the retina. the smaller waves are, however, far the most interesting and the most tractable to ordinary optical experiments. from a small oscillator, which may be a couple of small cylinders kept sparking into each other end to end by an induction coil, waves are emitted on which all manner of optical experiments can be performed. they can be reflected by plain sheets of metal, concentrated by parabolic reflectors, refracted by prisms, concentrated by lenses. i have at the college a large lens of pitch, weighing over three hundredweight, for concentrating them to a focus. they can be made to show the phenomenon of interference, and thus have their wave length accurately measured. they are stopped by all conductors and transmitted by all insulators. metals are opaque, but even imperfect insulators such as wood or stone are strikingly transparent, and waves may be received in one room from a source in another, the door between the two being shut. the real nature of metallic opacity and of transparency has long been clear in maxwell's theory of light, and these electrically produced waves only illustrate and bring home the well known facts. the experiments of hertz are in fact the apotheosis of that theory. thus, then, in every way maxwell's brilliant perception of the real nature of light is abundantly justified; and for the first time we have a true theory of light, no longer based upon analogy with sound, nor upon a hypothetical jelly or elastic solid. light is an electro-magnetic disturbance of the ether. optics is a branch of electricity. outstanding problems in optics are being rapidly solved now that we have the means of definitely exciting light with a full perception of what we are doing and of the precise mode of its vibration. it remains to find out how to shorten down the waves--to hurry up the vibration until the light becomes visible. nothing is wanted but quicker modes of vibrations. smaller oscillators must be used--very much smaller--oscillators not much bigger than molecules. in all probability--one may almost say certainly--ordinary light is the result of electric oscillation in the molecules of hot bodies, or sometimes of bodies not hot--as in the phenomenon of phosphorescence. the direct generation of _visible_ light by electric means, so soon as we have learnt how to attain the necessary frequency of vibration, will have most important practical consequences. speaking in this university, it is happily quite unnecessary for me to bespeak interest in a subject by any reference to possible practical applications. but any practical application of what i have dealt with this evening is apparently so far distant as to be free from any sordid gloss of competition and company promotion, and is interesting in itself as a matter of pure science. for consider our present methods of making artificial light; they are both wasteful and ineffective. we want a certain range of oscillation, between , and , billion vibrations per second; no other is useful to us, because no other has any effect upon our retina; but we do not know how to produce vibrations of this rate. we can produce a definite vibration of one or two hundred or thousand per second; in other words, we can excite a pure tone of definite pitch; and we can demand any desired range of such tones continuously by means of bellows and a keyboard. we can also (though the fact is less well known) excite momentarily definite ethereal vibrations of some million per second, as i have explained at length; but we do not at present seem to know how to maintain this rate quite continuously. to get much faster rates of vibration than this we have to fall back upon atoms. we know how to make atoms vibrate; it is done by what we call "heating" the substance, and if we could deal with individual atoms unhampered by others, it is possible that we might get a pure and simple mode of vibration from them. it is possible, but unlikely; for atoms, even when isolated, have a multitude of modes of vibration special to themselves, of which only a few are of practical use to us, and we do not know how to excite some without also the others. however, we do not at present even deal with individual atoms; we treat them crowded together in a compact mass, so that their modes of vibration are really infinite. we take a lump of matter, say a carbon filament or a piece of quicklime, and by raising its temperature we impress upon its atoms higher and higher modes of vibration, not transmuting the lower into the higher, but superposing the higher upon the lower, until at length we get such rates of vibration as our retina is constructed for, and we are satisfied. but how wasteful and indirect and empirical is the process. we want a small range of rapid vibrations, and we know no better than to make the whole series leading up to them. it is as though, in order to sound some little shrill octave of pipes in an organ, we are obliged to depress every key and every pedal, and to blow a young hurricane. i have purposely selected as examples the more perfect methods of obtaining artificial light, wherein the waste radiation is only useless and not noxious. but the old-fashioned plan was cruder even than this; it consisted simply in setting something burning; whereby not the fuel but the air was consumed, whereby also a most powerful radiation was produced, in the waste waves of which we were content to sit stewing, for the sake of the minute--almost infinitesimal--fraction of it which enabled us to see. every one knows now, however, that combustion is not a pleasant or healthy mode of obtaining light; but every one does not realize that neither is incandescence a satisfactory and unwasteful method which is likely to be practiced for more than a few decades, or perhaps a century. look at the furnaces and boilers of a great steam engine driving a group of dynamos, and estimate the energy expended; and then look at the incandescent filaments of the lamps excited by them, and estimate how much of their radiated energy is of real service to the eye. it will be as the energy of a pitch pipe to an entire orchestra. it is not too much to say that a boy turning a handle could, if his energy were properly directed, produce quite as much real light as is produced by all this mass of mechanism and consumption of material. there might, perhaps, be something contrary to the laws of nature in thus hoping to get and utilize some specific kind of radiation without the rest, but lord rayleigh has shown in a short communication to the british association at york that it is not so, and that, therefore, we have a right to try to do it. we do not yet know how, it is true, but it is one of the things we have got to learn. any one looking at a common glow-worm must be struck with the fact that not by ordinary combustion, nor yet on the steam engine and dynamo principle, is that easy light produced. very little waste radiation is there from phosphorescent things in general. light of the kind able to affect the retina is directly emitted; and for this, for even a large supply of this, a modicum of energy suffices. solar radiation consists of waves of all sizes, it is true; but then solar radiation has innumerable things to do besides making things visible. the whole of its energy is useful. in artificial lighting nothing but light is desired; when heat is wanted it is best obtained separately by combustion. and so soon as we clearly recognize that light is an electric vibration, so soon shall we begin to beat about for some mode of exciting and maintaining an electrical vibration of any required degree of rapidity. when this has been accomplished the problem of artificial lighting will have been solved. * * * * * on purification of air by ozone--with an account of a new method.[ ] [footnote : paper read in section c, domestic health, at the hastings health congress, on friday, may , .] by dr. b. w. richardson. during the time when i was engaged in my preliminary medical studies--for i never admit to this day of being anything less than a medical student--the substance called ozone became the topic of much conversation and speculation. i cannot say that ozone was a discovery of that date, for in the early part of the century von marum had observed that when electrical discharges were made through oxygen in a glass cylinder inverted over water, the water rose in the cylinder as if something had either been taken away from the gas, or as if the gas itself had been condensed, and was therefore occupying a smaller space. it had also been observed by many electricians that during a passage of the electric spark through air or oxygen, there was a peculiar emanation or odor which some compared to fresh sea air, others to the air after a thunderstorm, when the sky has become very clear, the firmament blue, and the stars, if visible, extremely bright. but it was not until the time, or about the time, of which i have spoken, - , that these discovered but unexplained phenomena received proper recognition. the distinguished physicist schonbein first, if i may so say, isolated the substance which yielded the phenomena, and gave to it the name, by which it has since generally been known, of _ozone_, which means, to emit an odor; a name, i have always thought, not particularly happy, but which has become, practically, so fully recognized and understood, that it would be wrong now to disturb it. schonbein made ozone by the action of the electric spark on oxygen. he collected it, he tested its chemical properties, he announced it to be oxygen in a modified form, and he traced its action as an active oxidizer of various substances, and especially of organic substances, even when they were in a state of decomposition. but schonbein went further than this. he argued that ozone was a natural part of the atmosphere, and that in places where there was no decomposition, that is to say, in places away from great towns, ozone was present. on the high tower of a cathedral in a big city he discovered ozone; in the city, at the foot of the tower, he found no ozone at the same time. he argued, therefore, that the ozone above was used up in purifying the town below, and so suggested quite a new explanation of the purification of air. the subject was very soon taken up by english observers, and i remember well a lecture upon it by michael faraday, in which that illustrious philosopher, confirming schonbein, stated that he had discovered ozone freely on the brighton downs, and had found the evidence of it diminishing as he approached brighton, until it was lost altogether in the town itself. such was the beginning of our knowledge of ozone, the precise nature of which has not yet been completely made out. at the present time it is held to be oxygen condensed. to use a chemical phrase, the molecule of oxygen, which in the ordinary state is composed of two atoms, is condensed, in ozone, as three atoms. by the electric spark discharged in dry oxygen as much as per cent. may, under proper conditions, be turned into ozone. ozone has also been found to be heavier than air. professor zinno says, that compared with an equal volume of air its density is equal to , , and that it is forty-eight times heavier than hydrogen. heat decomposes it; at the temperature of boiling water it begins to decompose. in water it is much less soluble than oxygen, and indeed is practically insoluble; when made to bubble through boiling water, it ceases to be ozone. the oxidizing power of ozone is very much greater than that of oxygen, and, according to saret, when ozone is decomposed, one part of it enters into combination, the other remains simply as oxygen. it is remarkable that some substances, like turpentine and cinnamon, absorb ozone and combine with it, a simple fact of much greater importance than has ever been attached to it. i found, for instance, that cinnamon which by exposure to the air has been made odorless and, as it is said, "spoiled," can be made to reabsorb ozone and gain a kind of freshness. it is certain also that some substances which are supposed to have disinfecting properties owe what virtues they possess to the presence of ozone. on some grand scale ozone is formed in the air, and my former friend and colleague, the late dr. moffatt, of hawarden, with whom i wrote a paper on "meteorology and disease," read before the epidemiological society in - , described what he designated ozone periods of the atmosphere, connecting these with storms. when the atmospheric pressure is decreasing, when with that there is increasing warmth and moisture, and when south and southwesterly winds prevail, then ozone is active; but when the atmospheric pressure is increasing, when the air is becoming dry and cold, and north and northeasterly winds prevail, then the presence of ozone is less active. these facts have also been put in another way, namely, that the maximum period of ozone occurs when there is greatest evaporation of water from the earth, and the minimum when there is greatest condensation of water on the earth; a theory which tallies well with the idea that ozone is most freely present when electricity is being produced, least present when electricity is in smallest quantity. mr. buchan, reporting on the observations of the scottish meteorological society, records that ozone is most abundant from february to june, when the average amount is . ; and least from july to january, when the average is . ; the maximum, . , being reached in may, and the minimum, . , in november. this same excellent observer states that "ozone is more abundant on the sea coast than inland; in the west than the east of great britain; in elevated than in low situations; with southwest than with northeast winds; in the country than in towns; and on the windward than the leeward side of towns." recently a very singular hypothesis has been broached in regard to the blue color of the firmament and ozone. it has been observed that when a tube is filled with ozone, the light transmitted through it is of a blue color; from which fact it is assumed that the blue color of the sky is due to the presence of this body in the higher atmospheric strata. the hypothesis is in entire accord with the suggestion of professor dove, to which moffatt always paid the greatest respect, viz., that the source of ozone for the whole of the planet is equatorial, and that the point of development of ozone is where the terrestrial atmosphere raised to its highest altitude, at the equator, expands out north and south in opposite directions toward the two poles, to return to the equator over the earth as the trade winds. it is necessary for all who would understand the applications of ozone for any purpose, whether for bleaching purposes or pure chemical purposes, or for medical or sanitary purposes, to understand these preliminary facts concerning it, facts which bring me to the particular point to which i wish to refer to-day. in my essay describing the model city, hygeiopolis, it was suggested that in every town there should be a building like a gas house, in which ozone should be made and stored, and from which it should be dispensed to every street or house at pleasure. this suggestion was made as the final result of observations which had been going on since i first began to work at the subject in . it occurred to me from the moment when i first made ozone by schonbein's method, that the value of it in a hygienic point of view was incalculable. to my then young and enthusiastic mind it seemed that in ozone we had a means of stopping all putrefaction, of destroying all infectious substances, and of actually commanding and destroying the causes which produced the great spreading diseases; and, although increase of years and greater experience have toned down the enthusiasm, i still believe that here one of the most useful fields for investigation remains almost unexplored. in my first experiments i subjected decomposing blood to ozone, and found that the products of decomposition were instantly destroyed, and that the fluid was rendered odorless and sweet. i discovered that the red corpuscles of fresh blood decomposed ozone, and that coagulated blood underwent a degree of solution through its action. i put dead birds and pieces of animal substances that had undergone extreme decomposition into atmospheres containing ozone, and observed the rapidity with which the products of decomposition were neutralized and rendered harmless. i employed ozone medicinally, by having it inhaled by persons who were suffering from foetor of the breath, and with remarkable success, and i began to employ it and have employed it ever since (that is to say, for thirty-seven years), for purposes of disinfection and deodorization, in close rooms, closets, and the like. i should have used it much more largely but for one circumstance, namely, the almost impracticable difficulty of making it with sufficient ease and in sufficient quantities to meet the necessities of sanitary practice. we are often obstructed in this way. we know of something exceedingly useful, but we cannot utilize it. this was the case with ozone. i hope now that difficulty is overcome. if it is, we shall start from this day on a new era in regard to ozone as an instrument of sanitation. as we have seen, ozone was originally made by charging dry oxygen or common dry air with electricity from sparks or points. afterward faraday showed that it could be made by holding a warm glass rod in vapor of ether. again he showed that it could be made by passing air over bright phosphorus half immersed in water. then siemens modified the electric process by inventing his well known ozone tube, which consists of a wide glass tube coated with tinfoil on its outside, and holding within it a smaller glass tube coated with tinfoil on its surface. when a current of dry air or oxygen was passed in current between these two tubes, and the electric spark from a ruhmkorf coil was discharged by the terminal wires connected with tinfoil surfaces, ozone was freely produced, and this was no doubt the best method, for by means of a double-acting hand bellows currents of ozone could be driven over very freely. one of these tubes with hand bellows attached, which i have had in use for twenty-four years, is before the meeting, and answers as well as ever. the practical difficulty lies in the requirement of a battery, a large coil, and a separate bellows as well as the tube. my dear and most distinguished friend, the late professor polli, of milan, tried to overcome the difficulties arising from the use of the coil by making ozone chemically, namely, by the decomposition of permanganate of potassa with strong sulphuric acid. he placed the permanganate in glass vessels, moistened it gradually with the acid, and then allowed the ozone, which is formed, to diffuse into the air. in this way he endeavored, as i had done, to purify the air of rooms, especially those vitiated by the breaths of many people. when he visited me, not very long before his death, he was enthusiastic as to the success that must attend the utilization of ozone for purification, and when i expressed a practical doubt, he rallied me by saying i must not desert my own child. at the theater la scala, on the occasion of an unusually full attendance, polli collected the condensible part of the exhaled organic matter, by means of a large glass bell filled with ice and placed over the circular opening in the roof, which corresponds with the large central light. the deposit on this bell was liquid and had a mouldy smell; was for some few days limpid, but then became very thick and had a nauseous odor. when mixed with a solution of one part glucose to four parts of water, and kept at a temperature of from ° to ° c., this liquid underwent a slow fermentation, with the formation, on the superficies, of green must; during the same period of time, and placed under the same conditions, a similar glucose solution underwent no change whatever. by the use of his ozone bottles polli believed that he had supplied a means most suitable for directly destroying in the air miasmatic principles, without otherwise interfering with the respiratory functions. the ozonized air had neither a powerful nor an offensive smell, and it might be easily and economically made. the smell of ozone was scarcely perceptible, and was far less disagreeable than chlorine, bromine, and iodine, while it was more efficacious than either of these; if, therefore, its application as a purifier of a vitiated air succeeded, it would probably supply all the exigences of defective ventilation in crowded atmospheres. in confined places vessels might be placed containing mixtures of permanganate of potassa or soda and acid in proper quantities, and of which the duration of the action was known; or sulphuric acid could be dropped upon the permanganate. this idea of applying ozone was no doubt very ingenious, and in the bottles before us on the table, which have been prepared in hastings by mr. rossiter, we see it in operation. the disadvantages of the plan are that manipulation with strong sulphuric acid is never an agreeable or safe process, and that the ozone evolved cannot be on a large scale without considerable trouble. in dr. lender published a process for the production of ozone. in this process he used equal parts of manganese, permanganate of potash, and oxalic acid. when this mixture is placed in contact with water, ozone is quickly generated. for a room of medium size two spoonfuls of this powder, placed in a dish and occasionally diluted with water, would be sufficient. as the ozone is developed, it disinfects the surrounding air without producing cough. lender's process is very useful when ozone is wanted on a limited scale. we have some of it here prepared by mr. rossiter, and it answers exceedingly well; but it would be impossible to generate sufficient ozone by this plan for the large application that would be required should it come into general use. the process deserves to be remembered, and the physician may find it valuable as a means by which ozone may be medically applied, to wounds, or by inhalation when there are foetid exhalations from the mouth or nostrils. a new method. for the past ten or fifteen years the manufacture of ozone, for the reasons related above, has remained in abeyance, and it is to a new mode, which will, i trust, mark another stage of advancement, that i now wish to direct attention. some years since, mr. wimshurst, a most able electrician, invented the electrical machine which goes by his name. the machine, as will be seen from the specimen of it on the table, looks something like the old electrical machine, but differs in that there is no friction, and that the plates of glass with their metal sectors, separated a little distance from each other, revolve, when the handle of the machine is turned, in opposite directions. the machine when it is in good working order (and it is very easily kept in good working order) produces electricity abundantly, and in working it i observed that ozone was so freely generated, that more than once the air of my laboratory became charged with ozone to an oppressive degree. the fact led me to use this machine for the production of ozone on a large scale, in the following way. from the terminals of the machine two wires are carried and are conducted, by their terminals, to an ozone generator formed somewhat after the manner of siemens', but with this difference, that the discharge is made through a series of fine points within the cylinders. the machine is placed on a table with the ozone generator at the back of it, and can be so arranged that with the turning of the handle which works the machine a blast of air is carried through the generator. thus by one action electricity is generated, sparks are discharged in the ozone generator, air is driven through, and ozone is delivered over freely. if it be wished to use pure oxygen instead of common air, nothing more is required than to use compressed oxygen and to allow a gentle current to pass through the ozone generator in place of air. for this purpose brin's compressed oxygen is the purest and best; but for ordinary service atmospheric air is sufficient.[ ] [footnote : for illustration to-day, messrs mayfield, the electrical engineers of queen victoria street, e. c., have been good enough to lend me a machine fitted up on the plan named. it works so effectively that i can make the ozone given off from it detectable in every part of this large hall.] the advantages of this apparatus are as follows: . with care it is always ready for use, and as no battery is required nor anything more than the turning of a handle, any person can work it. . it can be readily moved about from one part of a room or ward to another part. . if required for the sick it can be wheeled near the bedside and, by a tube, the ozone it emits can be brought into action in any way desired by the physician. i refer in the above to the minor uses of ozone by this method, but i should add that it admits of application on a much grander scale. it would now be quite easy in any public institution to have a room in which a large compound wimshurst could be worked with a gas engine, and from which, with the additional apparatus named, ozone could be distributed at pleasure into any part of the building. on a still larger scale ozone could be supplied to towns by this method, as suggested in hygeiopolis, the model city. it will occur, i doubt not, to the learned president of this section, and to others of our common profession, that care will have to be taken in the application of ozone that it be used with discretion. this is true. it has been observed in regard to diseases, that in the presence of some diseases ozone is absent in the atmosphere, but that with other diseases ozone is present in abundance. during epidemics of cholera, ozone is at a minimum. during other epidemics, like influenza, it has been at a maximum. in our paper dr. moffatt and i classified diseases under both conditions, and the difference must never be forgotten, since in some diseases we might by the use of ozone do mischief instead of good. moreover, as my published experiments have shown, prolonged inhalation of ozone produces headache, coryza, soreness of the eyes, soreness of the throat, general malaise, and all the symptoms of severe influenza cold. warm-blooded animals, also, exposed to it in full charge, suffer from congestion of the lungs, which may prove rapidly fatal. with care, however, these dangers are easily avoided, the point of practice being never to charge the air with ozone too abundantly or too long. a simple test affords good evidence as to presence of ozone. if into twenty ounces of water there be put one ounce of starch and forty grains of potassium iodide, and the whole be boiled together, a starch will be made which can be used as a test for ozone. if ozone be passed through this starch the potassium is oxidized, and the iodine, set free, strikes a blue color with the starch. or bibulous paper can be dipped in the starch, dried and cut into slips, and these slips being placed in the air will indicate when ozone is present. in disinfecting or purifying the air of a room with ozone, there is no occasion to stop until the test paper, by change of color, shows that the ozone has done its work of destroying the organic matter which is the cause of impurity or danger. for my own part, i have never seen the slightest risk from the use of ozone in an impure air. the difficulty has always been to obtain sufficient ozone to remove the impurity, and it is this difficulty which i hope now to have conquered.--_the asclepiad._ * * * * * heat in man. at a recent meeting of the physiological society of berlin, prof. zuntz spoke on heat regulation in man, basing his remarks on experiments made by dr. loewy. the store of heat in the human body at any one time is very large, equal, in fact, to nearly all the heat produced by the body during twenty hours, hence the heat given off to a calorimeter during a given period cannot be taken as a measure of the heat production. this determination must be based rather upon the amount of oxygen consumed and of carbonic acid gas given off. the purpose of the experiments was to ascertain what alteration the gaseous interchange of the body undergoes by the application of cold, inasmuch as existing data on this point are largely contradictory. the observations were made on a number of men whose respiratory gases were compared, during complete rest, when they were at one time clothed, at another time naked, at temperatures from ° to ° c., and in warm and cold baths. each experiment lasted from half an hour to an hour, during which period the gases were repeatedly analyzed. as a result of fifty-five experiments, twenty showed no alteration of oxygen consumption as the result of cooling, nine gave a lessened consumption, while the remaining twenty-six showed an increased using up of oxygen. this diversity of result is explicable on the basis of observations made by prof. zuntz, who was himself experimented upon, as to his subjective heat sensations during the experiments. he found that after the first impression due to the application of cold is overcome, it was quite easy to maintain himself in a perfectly passive condition; subsequently it required a distinct effort of the will to refrain from shivering and throwing the muscles into activity, and finally even this became no longer possible, and involuntary shivering and muscular contraction supervened, as soon as the body temperature (_in ano_) had fallen ½° to ° c. during the first stage of cooling, zuntz's oxygen consumption showed a uniform diminution; during the period also in which shivering was repressed by an effort of the will, cooling led to no increased consumption of oxygen, but as soon as shivering became involuntary there was at once an increased using up of oxygen and excretion of carbonic acid. this explains the differences in the results of dr. loewy's experiments, and may be taken to show that in man, and presumably in _large_ animals, heat regulation as directly dependent upon alteration (fall) in temperature of the surrounding medium does not exist; the increased heat production is rather the outcome of the movements resulting from the application of cold to the body. in _small_ animals, on the other hand, there undoubtedly exists a heat regulation dependent upon an increased activity of chemical changes in the tissues set up by the application of cold to the surface of the body, and in this case the thermotaxic centers in the brain most probably play some part.--dr. herter gave an account of experiments made by dr. popoff on the artificial digestion of various and variously cooked meats. lean beef and the flesh of eels and flounders were digested in artificial gastric juice; the amount of raw flesh thus peptonized was in all cases greater than that of cooked meat similarly treated. the flesh was shredded and heated by steam to ° c. the result was the same for beef as for fish. when compared with each other, beef was, on the whole, the most digestible, but the amount of fish flesh which was peptonized was sufficiently great to do away with the evil repute which fish still has in germany as a proteid food. smoked meat differed in no essential extent from raw meat as regards its digestibility. * * * * * preservation of spiders for the cabinet. for several years past, i have devoted a portion of my leisure time to the arrangement of the collection of arachnidæ of the natural history museum of the university of gand. this collection, which is partially a result of my own captures, is quite a large one, for a university museum, since it comprises more than six hundred european and foreign specimens. each group of individuals of the small forms and each individual of the large forms is contained in a bottle of alcohol closed with a ground glass stopper, and, whenever possible, the specimens have been spread out and fixed upon strips of glass. the loss of alcohol through evaporation is almost entirely prevented by paraffining the stoppers and tying a piece of bladder over them. properly labeled, the series has a very satisfactory aspect, and is easily consulted for study. the reader, however, will readily understand how much time and patience such work requires, and can easily imagine how great an amount of space the collection occupies, it being at least twenty times greater than that that would be taken up by a collection of an equal number of insects mounted in the ordinary way on pins and kept in boxes. these inconveniences led me to endeavor to find out whether there was not some way of preserving spiders, properly so called, in a dry state, and without distortion or notable modification of their colors. experience long ago taught me that pure and simple desiccation, after a more or less prolonged immersion in alcohol, gives passable results only with scorpions, galeodes, phrynes, and mygales, and consequently with arachnides having thick integuments, while it is entirely unsuccessful with most of the spiders. the abdomen of these shrivels, the characteristic colors disappear in great part, and the animals become unrecognizable. something else was therefore necessary, and i thought of carbolated glycerine. my process, which i have tried only upon the common species of the country--_tegenaria domestica_, _epeira cucurbitina_, _zilla inclinata_, etc., having furnished me with preparations that were generally satisfactory. i think i shall be doing collectors a service by publishing it in the _naturaliste_. the specimens should first be deprived of moisture, that is to say, they should be allowed to remain eight or ten days in succession in per cent. alcohol and in pure commercial alcohol. absolute alcohol is not necessary. after being taken from the alcohol, and allowed to drain, the specimens are immersed in a mixture compound of pure glycerine volumes, pure carbolic acid in crystals volume. in this they ought to remain at least a week, but there will be no harm if they are left therein indefinitely, so that the collections of summer may be mounted during winter evenings. what follows is a little more delicate, although very easy. after being removed from the carbolated glycerine, the spiders are placed upon several folds of white filtering paper, and are changed from time to time until the greatest part of the liquid has been absorbed. an insect pin is then passed through the cephalothorax of each individual and is inserted in the support upon which the final desiccation is to take place. this support consists of a piece of sheet cork tacked or glued at the edges to a piece of wood at least one inch in thickness. upon the cork are placed four or five folds of filtering paper, so that the ventral surface of the pinned spider is in contact with this absorbing surface. for the rest, the legs, palpi, spinnerets, etc., are spread out by means of fine pins, precisely as would be done in the case of coleoptera. [illustration: setting board for spiders. a. absorbent papers. b. sheet cork. c. wooden support.] the setting board is put for two or three months in a very dry place under cover from dust. the spiders thus treated will scarcely have changed in appearance, the abdomen of the largest epeiras will have preserved its form, the hairs will in nowise have become agglutinated, and a person would never suspect that glycerine had performed the role. the forms with a large abdomen require a special precaution; it is necessary to pass the mounting pin through a piece of thin cardboard or of gelatine prolonged behind under the abdomen, because the latter is heavy, and the pedicel that connects it with the cephalothorax easily breaks. the specimens are mounted in boxes lined with cork, just as insects are. as there is nothing simpler than to have in one's laboratory three bottles, two of them containing alcohol and the other containing carbolated glycerine, and as it is easy to make setting boards capable of holding from twenty to thirty individuals at once, it will be seen that, with a little practice, the method is scarcely any more complicated than the one daily employed for coleoptera and orthoptera, which latter, too, must pass through alcohol, and be pinned, spread out, and dried. there are but two additional elements, carbolated glycerine and absorbent paper. i do not estimate the time necessary for desiccation as being very long, since the zoologist can occupy himself with other subjects while the specimens are drying. let us add that the process renders the preservation indefinite, and that destructive insects are not to be feared. some vertebrates, such as monkeys, that i preserved in the flesh ten years ago, by a nearly identical method, are still intact.--_f. plateau, in le naturaliste._ * * * * * dried wine grapes. according to a report of the committee of the grape growers' and wine maker's association of california, the drying of wine grapes on a large scale was begun during the vintage season of , in which season about eight carloads in all were made and sold, the bulk of which came from the vicinity of fresno; that year, the committee are informed, the growers netted about three and a half cents per pound. during the season of about carloads were dried, packed, and sold, netting the growers from two and a half to three and a half cents per pound, depending on the quality of the fruit. the great bulk of that year's product has entered into consumption, but there yet remains unsold to consumers, we are informed, about ten carloads, which, it is expected, will be sold during the next three months. it has been observed by those handling this product that the largest sales of dried wine grapes in and took place at those points to which the first lots were shipped in , which would show that as the product becomes better known it finds a readier market. dried wine grapes are prepared in a similar manner to raisins; that is they are dried in the sun, but do not require the same care in handling that are given to raisins. wooden trays × are sometimes used, but it is by no means necessary to go to the expense of procuring trays, as it has been found that a good quality of coarse brown paper will answer every purpose, and this, with care, may be made to last two or three seasons. the drying was last season principally done on the bare ground, but there is much loss by shelling, as those dried are required to be turned; a pitchfork is used for that purpose. brown building paper can be procured of city paper dealers in large rolls at four and a half cents per pound; according to the thickness, it will cost from one and three-quarters to three and a half cents per square yard. a thin, tough, waterproof paper is also made in rolls at about six cents a square yard. wine grapes dry in from ten days to three weeks, according to variety and weather, and with the exception of malvoisie, rose of peru, and black hamburg, from three and a half to four and a half tons of the green fruit are required to make one of the dried; these three varieties, however, being large, meaty, and a firm pulp, do not require more than from three to three and a half tons of the green fruit to produce one ton of dried, and are, therefore, the most profitable for drying; they also command better values in the market. the grapes are sufficiently dried when, on being rolled between the thumb and finger, no moisture exudes, and also when the stems are found to be dry and brittle, so that they can be separated readily from the berries. after the grapes have reached the proper state of dryness, they are taken in boxes or sacks to the packing house, where they are stemmed and cleaned, after which they are packed in white cotton sacks, holding from fifty to seventy-five pounds each, and when marked are ready for shipment. the stemming and cleaning of the dried grapes is done by special machines designed for that purpose, which leaves the fruit in a bright, clean condition attractive to purchasers. these machines are at present built only by james porteous, fresno, and are operated either by hand or power. the cost of a stemmer and cleaner complete is $ , f. o. b. cars at fresno. where several producers can do so, it would be advisable to club together and get the machine in this way. much extra expense could be avoided and one set of machinery would serve several vineyards, possibly an entire district where time was not a great object; or some one person in a district could purchase an outfit and do the work by contract, going from place to place. the capacity of the stemmer and cleaner is from five to eight tons per day, when the grapes are in proper condition; and the cost or charge for stemming, cleaning, sacking, and sewing up the sacks is from four to five dollars per ton when the producer furnishes the sacks. good cotton sacks, holding about seventy-five pounds, cost from eight to ten cents each, including the necessary twine. last year dried grapes were generally sold for cash, f. o. b., but it is probable that other markets could be secured by selling on consignment. as to the advisability of such a course, each producer must himself be the judge. it is, however, quite certain that until consumers have an opportunity to try this product, the sales will necessarily be more or less limited, unless vigorously pushed by merchants and others interested in extending the markets for california products in the eastern cities not yet tried. the varieties most suitable and profitable for drying, and especially for consumption in the eastern markets, are the malvoisie, rose of peru, black hamburg, mission, zinfandel, charbono, grenache, and in some localities the carignan, of the dark varieties, and the feher zagos and golden chasselas of the white grapes; there are many other white grapes that are excellent when dried, but are too valuable for wine-making purposes, or are too small or deficient in sugar for use as dried grapes. the same is true of the dark grapes, some of which ripen so late that it would be impossible to dry them in the sun, and the use of artificial heat is, at present prices, too expensive. therefore, the varieties mentioned, which generally mature early, are found to be the most suitable for this purpose. this product is sold by dealers in the eastern cities for cooking purposes, and as a substitute for dried fruits, such as peaches, apples, apricots, etc., in comparison with which it is usually much cheaper; while for stewing and for puddings and pies it answers the same purpose. the demand for this product will probably be gauged by the eastern fruit crop; that is, the quantity that can be disposed of will depend upon the quantity of eastern fruit in the market, and the prices will be largely dependent upon that of dried fruit. * * * * * walnut oil. by thomas t. p. bruce warren. this oil, which i obtained from the fully ripened nut of the _jugluns regia_, has so many excellent properties, especially for mixing with artists' colors for fine art work, that i am surprised at the small amount of information available on this interesting oil. walnut oil is largely used for adulterating olive oil, and to compensate for its high iodine absorption it is mixed with pure lard oil olein, which also retards the thickening effect due to oxidation. the marc left on expression of the oil is said to be largely used in the manufacture of chocolate. many people, i am told, prefer walnut oil to olive oil for cooking purposes. the value of this oil for out-door work has been given me by a friend who used it for painting the verandas and jalousies of his house (near como, italy) some twenty years ago, and which have not required painting since. in this country, at least, walnut oil is beyond the reach of the general painter, and i do not know that the pure oil is to be obtained as a commercial article, even on a small scale. it was in examining the properties of this and other oils, used as adulterants of olive oil, that i was obliged to prepare them so as to be sure of getting them in a reliable condition as regards purity. the walnuts were harvested in the autumn of , and kept in a dry airy room until the following march. the kernels had shrunk up and contracted a disagreeable acrid taste, so familiar with old olive oil in which this has been used as an adulterant. most oxidized oils, especially cotton seed oil, reveal a similar acrid taste, but walnut oil has, in addition, an unmistakable increase in viscosity. the nuts were opened and the kernels thrown into warm water, so as to loosen the epidermis; they were then rubbed in a coarse towel, so as to blanch them. the decorticated nuts were wiped dry and rubbed to a smooth paste in a marble mortar. the paste was first digested in cs , then placed in a percolator and exhausted with the same solvent, which was evaporated off. the yield of oil was small, but probably, if the nuts had been left to fully ripen on the trees without knocking them off, the yield might have been greater. it is by no means improbable that oxidation may have rendered a portion of the oil insoluble. the decorticated kernels gave a perfectly sweet, inodorous, and almost colorless oil, which rapidly thickens to an almost colorless, transparent, and perfectly elastic skin or film, which does not darken or crack easily by age. these are properties which, for fine art painting, might be of great value in preserving the tinctorial purity and freshness of pigments. sulphur chloride gives a perfectly white product with the fresh oil, but, when oxidized, the product is very dark, almost black. the iodine absorption of the fresh oil thus obtained is very high, but falls rapidly by oxidation or blowing. a curious fact has been disclosed with reference to the oxidation of this and similar oils. if such an oil be mixed with lard oil, olive oil, or sperm oil, it thickens by oxidation, but is perfectly soluble. such a mixture is largely used in weaving or spinning. commercial samples of linseed oil, when cold-drawn, have a much higher iodine absorption, probably due to the same cause. oils extracted by cs are very much higher than the same oils, especially if hot-pressed.--_chem. news._ * * * * * the pyro developer with metabisulphite of potash. by dr. j. m. eder. lately i called attention to the metabisulphite of potassium as an addition to the pyro solution for development, and can give now some of my experiences with this salt. the metabisulphite of potassium, which was introduced into the market by dr. schuchardt, and whose correct analysis is not known yet, is a white crystal, which in a solid condition, as well as in an aqueous solution, has a strong smell of sulphurous acid. an aqueous per cent. solution of this salt dissolves pyrogallic acid to a weak yellowish color, being distinguished from the more light brown solution of sulphite of soda and pyro. the solution kept very well for four weeks in half-filled bottles, and showed a better preservation than the usual solution of pyro and sulphite of soda. more than per cent. of the metabisulphite of potassium is without any advantage. if this solution is mixed with soda, a picture will develop rapidly, but the same will show a strongly yellow coloration in the gelatine film. sulphite of soda has to be added to the soda solution to obtain an agreeable brownish or black tone in the negatives. if the contents of metabisulphite and pyro-soda developer are increased, it will act very slowly; larger quantities of the metabisulphite of potassium, therefore, act like a strong retarder. in small quantities there is no injurious retarding action, but it will have the effect that the plates obtain very clear shadows in this developer, and that the picture appears slower, and will strengthen more slowly. the strongly retarding action of larger quantities of metabisulphite might be accounted for in that the bisulphite will give, with the carbonate of soda, monosulphite and soda bicarbonate, which latter is not a strong enough alkali to develop the bromide of silver strongly with pyro. an increase of soda compensates this retarding action of the metabisulphite of potassium. good results were obtained by me with this salt after several tests, by producing the following solutions: a. pyrogallic acid grammes. metabisulphite of potassium ½ " water c. c. this solution keeps for weeks in corked bottles. b. crystallized soda grammes. neutral sulphite of soda " water c. c. before using mix-- pyro solution a c. c. soda solution b " water " the developer acts about one and a half times slower than the ordinary pyro soda developer, approaching to the latter pretty nearly, and gives to the negatives an agreeable color and softness, with clear shadows. if the negatives are to be thinner, more water, say to c. c., is taken. if denser, then the soda is increased, and the water in the developer is reduced. an alum bath before fixing is to be recommended. an advantage of this development is the great durability of the pyro-meta sulphite solution. the cost price is about the same as that of the ordinary pyro developer. at all events, it is worth while to make further investigation with the metabisulphite of potassium, the same being also a good preservative for hydroquinone solutions.--_photographische correspondenz; reported in the photo. news._ * * * * * a new catalogue of valuable papers contained in scientific american supplement during the past ten years, sent _free of charge_ to any address. munn & co., broadway, new york. * * * * * the scientific american architects and builders edition. $ . a year. single copies, cts. this is a special edition of the scientific american, issued monthly--on the first day of the month. each number contains about forty large quarto pages, equal to about two hundred ordinary book pages, forming, practically, a large and splendid magazine of architecture, richly adorned 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and how procured. address munn & co., broadway, new york. branch office, and f st., washington, d. c. [illustration] scientific american supplement no. new york, january , scientific american supplement. vol. xxxi., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. biography.--charles goodyear.--the life and discoveries of the inventor of vulcanized india rubber, with portrait.-- illustration ii. biology.--can we separate animals from plants?--by andrew wilson.--a debated point well discussed.--the bases on which distinctions must be drawn iii. electricity.--a new electric ballistic target.--a target for investigations of the velocity of projectiles, now in use at the united states military academy, west point, n.y.-- illustration. electric erygmascope.--an electric lighting apparatus for examining earth strata in bore holes for geologists' and prospectors' use.-- illustration the electro-magnet.--by prof. silvanus thompson.--continuation of this exhaustive treatise, giving further details on special points of construction.-- illustrations iv. entomology.--potash salts.--the use of potash salts as insecticides, with accounts of experiments the outlook for applied entomology.--by dr. c.v. riley, u.s. entomologist.--the conclusion of prof. riley's lecture, treating of the branch of entomology with which his name is so honorably associated v. insurance.--the expense margin in life insurance.--elaborate review of the necessary expenses of conducting the insurance of lives, with tables and calculations vi. mathematics.--the trisection of any angle.--by frederic r. honey, ph.b.--a very ingenious demonstration of this problem, based on the properties of conjugate hyperbolas vii. meteorology.--note on the mt. blanc meteorological station the flood at karlsbad.--account of the recent flood and of its destructive effects.-- illustration viii. mechanical engineering.--station for testing agricultural machines.--a proposed establishment for applying dynamometer tests to agricultural machines.-- illustration steam engine valves.--by thomas hawley.--a review of modern slide valve practice, the lap, cut-off, and other points.-- illustrations ix. miscellaneous.--science in the theater.--curious examples of stage effect in fictitious mesmerizing and hypnotizing.-- illustrations theatrical water plays.--recent episodes in real water plays at hengler's circus, london.-- illustrations x. naval engineering.--the french ironclad war ship colbert.--an armored wood and iron ship, with central battery.-- illustration xi. physiology and hygiene.--newer physiology and pathology.--by prof. samuel bell. m.d.--an excellent presentation of modern practice in the light of bacteriology test card hints.--how to test the eyes for selecting eyeglasses and spectacles the composition of koch's lymph.--what prof. koch says it is and what it can do.--the cabled account of the disclosure so long waited for xii. technology.--firing points of various explosives.--the leading explosives, with the temperature of their exploding points tabulated the recovery of gold and silver from plating and gilding solutions--a paper of interest to silver and gold platers, as well as photographers water softening and purifying apparatus.--an apparatus for treatment of sewage, etc., chemically and by deposition.-- illustration * * * * * the french ironclad war ship colbert. the central battery ironclad colbert is one of the ten ships of the french navy that constitute the group ranking next in importance to the squadron of great turret ships, of which the formidable is the largest. the group consists of six types, as follows: . the ocean type; three vessels; the marengo, ocean, and suffren. . the friedland type, of which no others are built. . the richelieu type, of which no others are built. . the colbert type, of which there are two; the colbert and the trident. . the redoubtable type, of which no others are built. . the devastation type, of which no others are built. [illustration: the french ironclad war ship colbert.] the colbert was launched at brest in , and her sister ship, the trident, in . both are of iron and wood, and the following are the principal dimensions of the colbert, which apply very closely to the trident: she is ft. in. long, ft. in. beam, and ft. in. draught aft. her displacement is , tons, her indicated horse power is , , and her speed . knots. she has coal carrying capacity for tons, and her crew numbers . the thickness of her armor belt is . in., that protecting the central battery is . in. thick, which is also the thickness of the transverse armored bulkheads, while the deck is . in. in thickness. the armament of the colbert consists of eight . in. guns, two . in., six . in., two quick firing guns, and fourteen revolving and machine guns.--_engineering._ * * * * * a compound locomotive, built by the rhode island locomotive works, has been tried on the union elevated railroad, brooklyn, n.y. the engine can be run either single or compound. the economy in fuel was . per cent, and in water . per cent, over a simple engine which was tested at the same time. the smoothness of running and the stillness and comparative absence of cinders was fully demonstrated. * * * * * steam engine valves. [footnote: lecture delivered at wells memorial institute, boston, in the lowell free course for engineers. from report in the _boston journal of commerce_.] by thomas hawley. riding cut-off valves--peculiarities and merits of the different styles. in considering the slide valve in its simple form with or without lap, we find there are certain limitations to its use as a valve that would give the best results. the limitation of most importance is that its construction will not allow of the proper cut off to obtain all the benefits of expansion without hindering the perfect action of the valve in other particulars. at this economical cut off the opening of the steam port is very little and very narrow, and although this is attempted to be overcome by exceedingly wide ports, sixteen inches in width in many cases in locomotive work, this great width adds largely to the unbalanced area of the valve. the exhausting functions of the valve are materially changed at the short cut off, and when much lap is added to overcome this defect, there usually takes place a choking of the exhaust port. you might inquire, why not make the port wider, but this would increase the minimum amount of load on the valve, and this must not be overlooked. then the cut off is a fixed one, and we can govern only by throttling the pressure we have raised in the boiler or by using a cut off governor and the consequent wastes of an enormous clearance space. you will observe, therefore, that the plain slide valve engine gives the most general satisfaction at about two-thirds cut off and a very low economic result. the best of such engines will require forty-five to fifty pounds of steam per horse power per hour, and to generate this, assuming an evaporation of nine pounds of water to a pound of coal, would require between five and six pounds of coal per horse power per hour. and the only feature that the valve has specially to commend it is its extreme simplicity and the very little mechanism required to operate it. yet this is of considerable importance, and in consideration of some special features at its latest cut off, the attempt has been many times made to take advantage of these features. for instance, at ° advance, the valve opens very rapidly indeed and fully satisfies our requirements of a perfect valve. this is one good point, and in this position also the exhaust and compression can be regulated very closely and as desired without much lap, and as the opening of the exhaust port comes with the eccentric at its most rapid movement the release is very quick and as we would have it. this is only possible at the most uneconomic position of the valve as regards cut off. the aim of many engineers has been to take advantage of these matters by using the valve with ° angular advance of eccentric ahead of crank, for the admission, release, and compression of the steam, and provide another means of cutting off, besides the one already referred to, viz., cutting off the supply of steam to the chest, and overcome the objection in this one of large clearance spaces. this is done by means of riding cut off valves, often called expansion valves, of which, perhaps, the most widely known types in this vicinity are the kendall & roberts engine and the buckeye. the former is used in the simplest form of riding cut off, while the buckeye has many peculiar features that engineers, i find, are too prone to overlook in a casual examination of the engine. in these uses of the slide valve, too, means are suggested and carried out of practically balancing the valve. the origin of the riding cut off is most generally attributed to gonzenbach. his arrangement had two steam chests, the lower one provided with the ordinary slide valve of late cut off, and steam was cut off from this steam chest by the expansion valve covering the ports connecting with the upper steam chest. this had the old disadvantage that all the steam in the lower chest expanded with that in the cylinder, at a consequent considerable loss. this was further improved by causing the riding cut off to be upon the top of the main valve, instead of its chest, and resulted in a considerable reduction of the clearance space. this is the simplest form, and is shown in fig. . the steam is supplied by a passage through the main valve which operates exactly as an ordinary slide valve would. that is, the inside edges of the steam passage are the same as the ordinary valve, the additional piece on each end, if i may so term it, being merely to provide a passage for the steam which can be closed, instead of allowing the steam to pass the edge. the eccentric of the main valve is fastened to the shaft to give the proper amount of lead, and the desired release and compression, and the expansion valve is operated by a separate eccentric fastened in line with or ° ahead of the crank. when the piston, therefore, commences to move from the crank end to open the port, d, the expansion valve is forced by its eccentric in the opposite direction, and is closing the steam port and would have closed it before the piston reached quarter stroke, thus allowing the steam then in the cylinder to do work by expansion. the eccentric operating this expansion valve may be set to close this steam port at any point in the stroke that is desired, the closing occurring when the expansion valve has covered the steam port. continuing the movements of the valves, the two would move together until one or the other reached its dead center, when the movements would be in opposite directions. [illustration: fig. .] there are three ways of effecting the cut off in such engines, the main valve meanwhile being undisturbed, its eccentric fastened securely so as not to disturb the points of lead, release, and compression. all that is required is to cause the edge of the expansion valve to cover the steam port earlier in the stroke, and this can be done, first, by increasing the angular advance of the cut off eccentric; second, by adding lap to the cut off valve; and third by changing the throw of the eccentric. in all these instances the riding valve is caused to reach the edge of the steam port earlier in the stroke. we will take first, as the simplest, those methods by which the lap of the cut off valve is increased. it will be noted that there is but one edge of this valve that is required to do any work, and that is to close the valve. the eccentrics are so placed that the passage in the main valve is opened long before the main valve itself is ready to admit steam to the cylinder, so that only the outer edges are the ones to be considered, and it will be readily seen that the two valves traveling in opposite directions, any lap added to the working edge of the cut off valve will cause it to reach the edge and therefore close the port earlier than it would if there was less lap. and we might carry it to the extreme that we could add lap enough that the steam passage would not be opened at all. in fig. is shown the method by which this is accomplished, in what is called meyer's valve, and such as is used in the kendall & roberts engine. we have only one point to look after, the cut off, so we can add all the lap we wish without disturbing anything else. in this engine the lap is changed by hand by means of a little hand wheel on a stem that extends out of the rear of the steam chest. the valve is in two sections, and when it is desired to cut off earlier, the hand wheel is turned in such a direction that the right and left hand screws controlling the cut off valve move one valve portion back and the other forward, which would, if they were one valve and they should be so considered, have the effect of lengthening them, or adding lap to them. the result would be that the riding valve would reach the edge of the steam port earlier in the stroke, bringing about an earlier cut off. if the cut off is desired to be later, the hand wheel is so turned that the right and left hand screws will bring the valve sections nearer together, thus practically taking off lap. now this may be done by hand or it may be done by the action of a governor. [illustration: fig. .] in the latter case the governor at each change of load turns the right and left hand screws to add or take away lap, as the load demands an earlier or later cut off; in other cases the governor moves a rack in mesh with a gear by which the valve sections are brought closer together or are separated. the difficulty with the case where the hand wheel is turned by hand is that the cut off is fixed where you leave it, and governing can only be at the throttle. for this reason anywhere near full boiler pressure would not be obtained in the cylinder of the engine. if the load was a constant one, and the cut off could be fixed at about one-third, causing the throttle to open its widest, very good results would be obtained, but there is no margin left for governing. if the load should increase at such a time the governor could not control it under these conditions, and it would lead to a decrease in speed unless the lap was again changed to give a later cut off. on this account the general practice soon becomes to leave the cut off at the later point and give range to the throttle, and we come back once more to the plain slide valve cutting off at half stroke, and the only gain there is, is in a quick port opening and quick cut off. but these matters are more than offset by the wire drawing between the steam pipe and chest, through the throttle, and the fact that there is added to the friction of the engine the friction of this additional slide valve and a considerable liability to have a leaky valve. in the case where the governor changes the position of the cut off valve a greater decree of economy would result. in this engine, of which the lambertville engine is a type, the main valve is a long d slide, with multiple ports at the ends through which the steam enters the cylinders. it is operated from an eccentric on the crank shaft in the usual manner. the cut off valve is also operated from the motion on an eccentric fixed upon the crank shaft. the rod or stem of the cut off valve passes through the main valve rod and slide. upon the outer end of the cut off valve rod are tappets fastened to engage with tappets on the eccentric valve rod. connection between the cut off eccentric, therefore, and the cut off valve is only by means of the engagement of these tappets. the eccentric rod is fastened to a rocker arm having motion swinging about a pin or bearing in the governor slide, which may be raised or lowered by a cam operated by the governor. the cut off slide is of cylindrical shape and incloses a spring and dash pot with disks attached by means of which the valve is closed. the motion for operating the valves is relatively in the same direction, the cut off eccentric having the greatest throw and greater angular advance to cause it to open earlier and quickly before the main valve is ready to admit steam. the cut off eccentric rod swinging the rocker arm, the tappets thereon engage with those upon the cut off valve rod and open the passages to the main valve, and in their movement compress the spring in the main valve. according as the speed of the engine, the rock arm will be raised or lowered so that the tappets upon the eccentric rod may keep in engagement a shorter or longer time before they disengage, thus allowing the spring that has been compressed by the movement of the cut off valve to close that valve quickly and the supply of steam to the engine, the cut off valve traveling with the main valve for the balance of the stroke. this device will give a remarkably quick opening and a quick cut off, but in view of the fact that the governor has so much to do, its delicacy is impaired and a quick response to the demands of the load changing not so likely to occur. the cut off cannot be as quick as in some other engines, because the valves are moving in opposite directions, and while this fact would help, so far as shortening the distance to be traveled before cut off, the resistance of the valves to travel in opposite directions, or rather the tendency of the valve to travel with the main valve, hinders its rapid action. [illustration: fig. .] this is one great objection to the rack and gear operated by the governor, that two flat valves riding upon each other and sliding in opposite directions at times require a considerable amount of force to move them, and as only a slight change in load is required by the load, the governor cannot handle the work as delicately as it should. it is too much for the governor to do well. to overcome this difficulty the ryder cut-off, shown in fig. , was made by the delamater people, of new york. the main slide valve is hollowed in the back and the ports cut diagonally across the valve to form almost a letter v. the expansion valve is v-shaped, and circular to fit its circular-seat. the valve rod of the expansion valve has a sector upon it and operated by a gear upon the governor stem, which rotates the valve rod, and the edge of the valve rod is brought farther over the steam port, thus practically adding lap to the valve. little movement is found necessary to make the ordinary change in cut-off, and it is found to be much easier to move the riding valve across the valve than in a direction directly opposite. it would require considerable force to move the upper valve by the governor faster than the lower, or in a direction opposite to that in which it is moving, but very little force applied sideways at the same time it is moving forward will give it a sideways motion. in this device the governor has only to exert this side pressure and therefore has less to do than if it were called upon to move the upper valve directly against the movement of the lower. something similar is the valve of the woodbury engine, of rochester, n.y. the cut-off valve is cylindrical, covering diagonal ports directly opposite, and is caused to be rotated by the action of the governor that operates a rack in mesh with a segment. very little movement will effect a considerable change in the lappage of the valve, the valve turning about one-quarter a revolution for the extremes of cut off. the cut off valve rod works through a bracket and its end terminates in a ball in a socket on the end of the eccentric rod. in this case the governor has not as much to do as in other instances. [illustration: fig. .] still another method of effecting this change in cut off, but hardly by increasing the lap of the valve, is shown in the next drawing, fig. . the cut off valve is held upon the main valve by the pressure of steam upon its back and rides with it until it comes in contact with the cut off wedge-shaped blocks, when its motion is arrested, and the main valve continuing its movement the steam port is closed by the main valve passing beneath the cut off valve. thus the main valve travels and carries the cut off valve upon its back again until the cut off valve strikes the wedge on the other end and the cut off is effected. the relative positions of the blocks are determined by the governor, that will raise or lower them so that the cut off valve will engage with them earlier or later as desired. this device was designed specially as an inexpensive method of changing the common slide valve into an automatic cut off. the cut off would not be as quick as in other cases we have cited, depending here upon the movement of the lower valve alone, and that, too, is in its slowest movement; whereas in the other cases, the edges approaching each other, by the differing movement of the valves the cut off is very rapid, provided the distance to travel is not long. in this device considerable noise must result by the cut off valve striking the cut off blocks, and a considerable amount of leakage is likely to occur past this valve. but there is one great objection in the valve gears thus far cited, that the travel of the expansion valve upon the main valve is variable. i have in mind the case of a kendall & roberts engine, which had been run for a long time at no better economy than would be obtained from a plain slide valve engine, and when it was attempted to get an earlier cut off by separating the two cut off valves, they had worn so much in their old place on the valve that shoulders were found sufficient to cause a disagreeable noise and a leaky valve. this is very apt to occur, not only where the valve is run for a long time on one seat, but in cases of variation of the travel of the expansion valve. the result is that a change will bring about a leaky valve, something that every engineer abhors. the construction of the buckeye engine, which is also of this type, is such that the travel of the valve on the back of the main valve is always the same, no matter what the cut off may be. then this engine makes use of our second proposition as a means of effecting the cut off, viz., by advancing the eccentric. you will readily observe that anything that will cause the cut off valve to reach a certain point earlier in the stroke will bring about an earlier cut off as it hastens everything all around. this is the plan pursued in the buckeye, in which the governor, of the shaft type, turns the eccentric forward or back according as the load demands. then, in addition, the valve is balanced partially, the attempt not being made to produce an absolutely balanced valve, on the ground that there should be friction enough to keep the surfaces bright and to prevent leakage. the most perfect valve will, of course, be entirely balanced under all conditions of pressure so as to move with perfect ease. with the riding cut off valve in connection with the plain slide valve, this is not accomplished, and it does not matter whether it is partially unbalanced to prevent leakage or not, the fact that it is not entirely balanced prevents it reaching the ideal valve. [illustration: fig. ] this valve, fig. , differs from the others also in this particular, that the exhaust takes place at the end of the valve instead of under the arch. two eccentrics are used, the one for the main valve being fastened to the shaft and the other riding loosely upon it and connected to the fly wheel governor, by which it may be turned forward or back as the load requires. the three points of lead, or admission and exhaust and compression, are fixed and independent of the changes and cut off. the motion of the main eccentric is given to a rocker arm, the pivot of which is at the bottom, and from the upper end the valve rod transfers the motion to the valve without reversing the motion, as is done sometimes in the slide valve to overcome the effects of the angularity of the connecting rod. the action of the rocker arm, therefore, so far as the main valve in the buckeye is concerned, is no different than that which would occur if no rocker arm intervened. the motion of the cut off eccentric, through its eccentric rod, is given to a rocker rocking in a bearing in the center of the main rocker arm (see fig. ). the motion of this eccentric is reversed, so far as the cut off valve is concerned, and when the cut off eccentric is moving forward, the cut off valve is being pushed back. the main valve rod is hollow, and the cut off valve rod passes through it. [illustration: fig. ] the cut off eccentric can be placed in any position to cause it to cut off as desired, and by drawing the valve forward, by increasing the angular advance of the eccentric, the cut off valve is caused to reach and cover the steam passage in the main valve earlier in the stroke. instead of being ahead of the crank, the main eccentric in this arrangement follows the crank, on account of the exhaust and steam edges being exactly opposite from those in the ordinary slide. what is the steam edge of the common slide is in this the exhaust edge, and what is the exhaust edge in the common valve is the steam edge in this one. the valve, therefore, must be moved in the opposite direction from what is ordinarily the case, the main eccentric being not deg. behind the crank. it has a rapid and full opening just the same, for it is at this point behind the crank, or ahead of it, that the eccentric gives to the valve its quickest movement, or between the eccentric dead centers. the cut off eccentric is considerably ahead of the main eccentric, and about even with the crank. if it was not for the reversal of motion of the cut off valve through the rocker arm this eccentric would be about in line with the crank, but on the other end. the movement of the cut off valve, therefore, at the time of port opening is very little, being about on its dead center, passing which, it immediately commences to close. the object of the peculiar construction of the rocker arm, and the pivot for the cut off rocker being placed thereon, is to provide equal travel on the back of the main valve, no matter what the cut off. i have already explained, in connection with the slide valve, that advancing the eccentric does not change the movement of the valve on its seat, but simply its relation to the movement of the piston. you will see that this is unchanged as using the main valve as a seat or any other seat. if the main valve was to remain stationary, and only the cut off valve to be operated by its eccentric, the movement of this cut off valve on a certain plane would be the same for all positions of the eccentric. moving the main slide does not affect the matter in any way, for it moves at the same time the pivot of the cut off, and while the cut off seat has assumed a different position with reference to the engine, it is still as though stationary so far as the cut off valve is concerned. this is the object of this peculiar construction, and not, as some engineers suppose, simply to make an odd way of doing things. and the object of it all is to give at all cut offs the same amount of travel, so that there might be no unequal wear to bring about a leak, to prevent which a perfect balancing has been sacrificed. referring to the valve and this engine as to how it will satisfy our requirements of a perfect valve gear, we find that the first requirement of a rapid and full opening is met, in that the opening occurs when the main eccentric is moving very rapidly, yet not its fastest, and while this opening will be very satisfactory, it is not so rapid an opening as is obtained in some other forms of valves and valve gears, but this could be overcome very readily by increasing the lead a trifle, and in my experience with these engines i find that the practice is very general by engineers and by builders themselves to give them a considerable amount of lead. as to the second requirement, the maintenance of initial pressure until cut off, giving a straight steam line, cards from this engine will not be found to show that the engine satisfies this requirement, and for this reason, that the cut-off valve commences to close the port immediately after the piston commences to move. the cut off eccentric you will remember is set to move with the crank or very nearly so, and the lighter the load, the greater will this fact appear. for the lightest loads the governor places the eccentric in advance of the crank, so that the cut off valve will commence to close the port before steam is admitted by the main valve to the engine. now, the later the cut off, the less will this wire drawing appear at first, and the shorter the cut off, the amount of wire drawing increases sensibly. the operation of the valve, therefore, in this particular, cannot be considered as meeting our requirement that the port shall be held open full width until ready to be closed. many men claim for this engine that the closing occurs when the cut off eccentric is moving its fastest. this is a fact, and if we consider the point of cut off only to be the point of absolute cut off, the cut off must be instantaneous, for there is an instantaneous point where the cut off is final only to be considered. the reasoning applied here would hold good also to a less extent on the slide valve, but is not the point of absolute cut off. we want to note how long it is from the time the valve commences to close at all until finally closed, and, as i have shown you, this is considerable in this engine. referring to the point of cut off finally, it is determined upon by a governor of the fly wheel type. the eccentric is loose about the shaft, and arms projecting therefrom are connected by other arms to the extremity of an arm upon which is mounted a weight, and which is attached to the spokes of the fly wheel, or special governor wheel in this case, and which is fastened to the crank shaft. as the speed increases through throwing off a portion of the load the governor weights fly out, and this movement is transferred through the lever connections to the eccentric, causing it to be turned ahead, and the manner hastening the movement of the cut off valve on its seat and causing it to reach and cover the edge of the steam port earlier in the stroke. this engine was the pioneer in governors of this character, the advantage being, in addition to its necessity for the work of turning the eccentric ahead or back, that the liability of the engine to run away, as very often happens from the breaking of the governor belt or a similar cause, was not possible. the cut off valve has a travel considerably beyond the edge of the steam passage after the valve is closed, and this has one advantage, that the valve is less liable to leak, and to this must be added the loss from the friction of this moving valve, and moving too in opposition to the main valve. in our perfect valve, as we outlined it, the valve does not move after the port is closed. the exhausting functions of the valve are very good, giving a quick opening and a full opening, because this opening occurs when the eccentric is moving its fastest. the engine also possesses a distinct advantage in having remarkably small clearance spaces. the length of the steam passage is very small in comparison with any form of engine, and having but two ports instead of four, as in the corliss and four valve type. in these there must be included in the clearance, that to the exhaust port as well as the steam port, adding a considerable amount where the piston comes close to the head. as the engines leave the maker's hand the engines are provided with a considerable amount of lap to give plenty of compression, but are, of course, capable of having more added to increase compression, or some planed off to decrease it. one of the peculiar things about this engine is the failure to realize anywhere near boiler pressure, noticeable in every case that has come under my notice. the considerable lead gives it for an instant, but it soon falls away, indicating the steam chest pressure only by a peak at the junction of the admission and steam lines. this is probably due to the fact that the cut off valve commences closing the steam passage so soon after steam is admitted, and in this particular does not satisfy the requirements of a perfect valve. there is this about the engine, that above all others of this type there has come under my notice fewer engines of this type with a maladjustment of valves from tampering by incompetent engineers. * * * * * firing points of various explosives. an apparatus, devised by horsley, was used, which consisted of an iron stand with a ring support holding a hemispherical iron vessel, in which paraffin or tin was put. above this was another movable support, from which a thermometer was suspended and so adjusted that its bulb was immersed in molten material in the iron vessel. a thin copper cartridge case, / in. in diameter and - / in. long, was suspended over the bath by means of a triangle, so that the end of the case was in. below the surface of the liquid. on beginning the experiment the material in the bath was heated to just above the melting point, the thermometer was inserted in it, and a minute quantity of the explosive was placed in the bottom of the cartridge case. the temperature marked by the thermometer was noted as the _initial temperature_, the cartridge case containing the explosive was inserted in the bath, and the temperature quickly raised until the explosive flashed off or exploded, when the temperature marked by the thermometer was again noted as the _firing point_. the tables given show the results of about six experiments with each explosive. the initial temperatures range from ° to ° c. in some cases, but as the firing points remained fairly constant, only the extremes of the latter are quoted in the following table: --------------------------------+----------------------- description of explosive. | firing point in ° c. --------------------------------+----------------------- compressed military gun-cotton. | - air-dried military gun-cotton. | - " " " | - " " " | - " " " | - gun-cotton dried at ° c. | - air-dried collodion gun-cotton. | - " " " | - " " " | - air-dried gun-cotton. | - " " | - hydro-nitrocellulose. | - nitroglycerin. | - kieselghur dynamite. no. . | - explosive gelatin. | - explosive gelatin, camphorated. | - mercury fulminate. | - gunpowder. | - hill's picric powder. | - " " " | - forcite, no. . | - atlas powder, per cent. | - emmensite, no. . | - emmensite, no. . | - emmensite, no. . | - --------------------------------+----------------------- _--c.e. munroe, j. amer. chem. soc._ * * * * * station for testing agricultural machines. the minister of agriculture has recently established a special laboratory for testing agricultural _materiel_. this establishment, which is as yet but little known, is destined to render the greatest services to manufacturers and cultivators. in fact, agriculture now has recourse to physics and mechanics as well as to chemistry. now, although there were agricultural laboratories whose mission it was to fix the choice of the cultivator upon such or such a seed or fertilizer, there was no official establishment designed to inform him as to the value of machines, the models of which are often very numerous. _chemical_ advice was to be had, but _mechanical_ advice was wanting. it is such a want that has just been supplied. upon the report presented by mr. tisserand, director of agriculture, a ministerial decree of the th of january, , ordered the establishment of an experimental station. mr. ringelmann, professor of rural engineering at the school of grignon, was put in charge of the installation of it, and was appointed its director. he immediately began to look around for a site, and on the th of december, , the municipal council of paris, taking into consideration the value of such an establishment to the city's industries, decided that a plot of ground of an area of , square meters, situated on jenner street, should be put at the disposal of the minister of agriculture for fifteen years for the establishment thereon of a trial station. this land, bordering on a very wide street and easy of access, opposite the municipal buildings, offers, through its area, its situation, and its neigborhood, indisputable advantages. a fence meters in extent surrounds the station. an iron gate opens upon a paved path that ends at the station. the year was devoted to the installation, and the station is now in full operation. the tests that can be made here are many, and concern all kinds of apparatus, even those connected with the electric lighting that the agriculturist may employ to facilitate his exploitation. however, the tests that are oftenest made are ( ) of rotary apparatus, such as mills, thrashing machines, etc.; ( ) of traction machines, such as wagons, carts, plows, etc.; and ( ) of lifting apparatus. it is possible, also, to make experiments on the resistance of materials. the experimental hall contains a horse power gas motor, dynamometers with automatic registering apparatus, counters, balances, etc. a small machine shop contains a lathe, a forge, a drilling machine, etc. the main shaft is meters in length and is centimeters in diameter. it is supported at a distance of one meter from the floor by four pillow blocks, and is formed of three sections united by movable coupling boxes. out of these meters, are in the hall and extend beyond the hall to an annex, meters in length and in width, in which tests are made of machines whose operation creates dust. when the machines to be tested require more than the power of seven horses that the motor gives, the persons interested furnish a movable engine, which, placed under the annex, actuates the driving shaft. alongside of the main building there is a ring for experimenting upon machines actuated by a horse whim. there will soon be erected in the center of the grounds an meter tower for experiments on pumps. platforms spaced meters apart, a crane at the top, and some gauging apparatus will complete this hydraulic installation. the equipment of the hall is very complete, and is fitted for all kinds of experiments. [illustration: station for testing agricultural machines--dynamometer for testing rotary machines.] the tests of rotary machines are made by means of a dynamometer (see figure). two fast pulleys and one loose pulley are interposed between the machine to be tested and the motor. the pulley connected with the motor carries along the one connected with the machine, through the intermedium of spring plates, whose strength varies with the nature of the apparatus to be tested. the greater or less elongation of these plates gives the tangential stress exerted by the driving pulley to carry along the pulley that actuates the machine to be tested. this elongation is registered by means of a pencil connected with the spring plates, and which draws a diagram upon a sheet of paper. at the same time, a special totalizer gives the stress in kilogrammeters. besides, the pulley shaft actuates a revolution counter, and a clock measures the time employed in the experiment. in order to obtain a simultaneous starting and stopping point for all these apparatus, they are connected electrically, and, through the maneuver of a commutator, are all controlled at once. the electric current is furnished by two series of bichromate batteries. the tests of traction machines are effected by means of a three-wheeled vehicle carrying a dynamometer. the front wheel is capable of turning freely in the horizontal plane, and the dynamometer is mounted upon a frame provided with a screw that permits of regulating its position according to the slope of the ground. the method of suspension of the dynamometer allows it to take automatically the inclination of the line of traction without any torsion of the plates. there are two models of this vehicle, one designed to be drawn by a man, and the other by a horse. the station is provided, in addition, with registering pressure gauges, a large double dynamometric indicator, a counter of electricity, balances of precision, etc. an apparatus designed for measuring the rendering of presses is now in course of construction. although the station has been in operation only from the st of january, twenty-five machines have already been presented to be tested.--_extract from le genie civil_. * * * * * water softening and purifying apparatus. we have recently had brought under our notice a system of water and sewage purification which appears to possess several substantial advantages. chief among these are simplicity in construction and operation, economy in first cost and working and efficiency in action. this system is the invention of messrs. slack & brownlow, of canning works, upper medlock street, manchester, and the apparatus adopted in carrying it out is here illustrated. it consists of an iron cylindrical tank having inside a series of plates arranged in a spiral direction around a fixed center, and sloping downward at a considerable angle outward. the water to be purified and softened flows through the large inlet tube to the bottom, mixing on its way with the necessary chemicals, and entering the apparatus at the bottom, rises to the top, passing spirally round the whole circumference, and depositing on the plates all solids and impurities. all that is needed in the way of attention, even when dealing with sewage, or the most polluted waters, is stated to be the mixing in the small tanks the necessary chemical reagents, at the commencement of the working day; and at the close of the day the opening of the mud cocks shown in our engraving, to remove the collected deposit upon the plates. for the past six months this system has been in operation at a dye works in manchester, successfully purifying and softening the foul waters of the river medlock. it is stated that , gallons per day can be easily purified by an apparatus feet in diameter. the chemicals used are chiefly lime, soda, and alumina, and the cost of treatment is stated to vary from a farthing to twopence per , gallons, according to the degree of impurity of the water or sewage treated. the results of working at manchester show that all the visible filth is removed from the medlock's inky waters, besides which the hardness of the water is reduced to about ° from a normal condition of about °. the effluent is fit for all the varied uses of a dye works, and is stated to be perfectly capable of sustaining fish life. with results such as these the system should have a promising future before it in respect of sewage treatment, as well as the purification and softening of water generally for industrial and manufacturing purposes.--_iron._ [illustration: water softening and purifying apparatus.] * * * * * the trisection of any angle. by frederic r. honey, ph.b., yale university. the following analysis shows that with the aid of an hyperbola any arc, and therefore any angle, may be trisected. if the reader should not care to follow the analytical work, the construction is described in the last paragraph--referring to fig. ii. let a b c d (fig. i.) be the arc subtending a given angle. draw the chord a d and bisect it at o. through o draw e f perpendicular to a d. we wish to find the locus of a point c whose distance from a given straight line e f is one-half the distance from a given point d. in order to write the equation of this curve, refer it to the co-ordinate axes a d (axis of x) and e f (axis of y), intersecting at the origin o. let g c = x therefore, from the definition c d = x let o d = d [hence] h d = d-x let c h = y [hence] ( x)² = y² + (d-x)² or x² = y² + d²- dx + x² [hence] y²- x² + d²- dx = o [i.] this is the equation of an hyperbola whose center is on the axis of abscisses. in order to determine the position of the center, eliminate the x term, and find the distance from the origin o to a new origin o'. let e = distance from o to o' [hence] x = x' + e substituting this value of x in equation i. y²- (x' + e)² + d²- d(x' + e) = o or y²- x²- ex'- e² + d²- dx'- de = o [ii.] in this equation the x' terms should disappear. [hence] - ex' - dx' = o [hence] -e = - d/ that is, the distance from the origin o to the new origin or the center of the hyperbola o' is equal to one-third of the distance from o to d; and the minus sign indicates that the measurement should be laid off to the left of the origin o. substituting this value of e in equation ii., and omitting accents-- we have y² - x² + dx - d²/ + d² - dx + d²/ = o [hence] y² - x² = - d²/ [illustration: fig i] [illustration: fig ii] this is the equation of an hyperbola referred to its center o' as the origin of co-ordinates. to write it in the ordinary form, that is in terms of the transverse and conjugate axes, multiply each term by c, i.e., __ let \/c = semi-transverse axis. [tex: \sqrt{c} = \text{semi-transverse axis.}] thus cy² - cx² = - cd²/ . [iii.] when in this form the product of the coefficients of the x² and y² terms should be equal to the remaining term. that is c² = - cd²/ . [hence] c = d²/ . and equation iii. becomes: d² d² d^{ } ----- y² - ----- x² = - --------- [tex: \frac{ d^ }{ } y^ - \frac{ d^ }{ } x^ = -\frac{ d^ }{ }] ____ / d² d the semi-transverse axis = \/ ----- = ---- [tex: \text{the semi-transverse axis} = \sqrt{\frac{ d^ }{ }} = \frac{ d}{ }] ____ / d² d the semi-conjugate axis = \/ ----- = ----- ___ \/ [tex: \text{the semi-conjugate axis} = \sqrt{\frac{ d^ }{ }} = \frac{ d}{\sqrt{ }}] since the distance from the center of the curve to either focus is equal to the square root of the sum of the squares of the semi-axes, the distance from o' to either focus ____________ / d² d² d = /\ /----- + ----- = ---- \/ [tex: \sqrt{\frac{ d^ }{ } + \frac{ d^ }{ }} = \frac{ d}{ }] we can therefore make the following construction (fig. ii.) draw a d the chord of the arc a c d. trisect a d at o' and k. produce d a to l, making a l = a o' = o' k = k d. with a k as a transverse axis, and l and d as foci, construct the branch of the hyperbola k c c' c", which will intersect all arcs having the common chord a d at c, c', c", etc., making the arcs c d, c' d, c" d, etc., respectively, equal to one-third of the arcs a c d, a c' d, a c" d, etc. * * * * * test card hints. by dr. f. ogden stout. i know it is the custom with a great many if not the majority of opticians to fit a customer without knowing whether he has presbyopia, hypermetropia, or any of the other errors of refraction. their method is first to try a convex, and if this does not improve, a concave, etc., until the proper one is found. this, of course, amounts to the same thing if the right glass is found. but in practice it will be found both time saving and more satisfactory to first decide with what error you have to deal. it is very simple, and, where you have no other means of diagnosing (such as the ophthalmoscope), it does away with the necessity of trying so many lenses before the proper one is found. you should have a distance test card placed at a distance of twenty feet from the person you are examining, and in a good light. a distance test card consists of letters of various sizes which it has been found can be seen at certain distances by people with good vision. thus the largest letter is marked with a cc, meaning that this should be seen at two hundred feet, and another line, xx, at twenty feet, which is the proper distance for testing vision for distance, for the reason that a normal eye is at rest when looking at any object twenty feet from it or beyond, and the rays coming from it are parallel and come to a focus on the retina. you must also have a near vision test card with lines that should be seen by a normal eye from ten to seventy-two inches, and a card of radiating lines for astigmatism. with this preparation you are ready to proceed. to illustrate, the first customer comes and tells you that up to six months ago he had very good vision, but he finds now that, especially at night, he has trouble in reading or writing, and that he finds he can see better a little farther away. his head aches and eyes smart. you will of course say that this is a very simple case. it must be old sight (presbyopia). probably it is if he is old enough ( ), but you must prove this for yourself, without asking his age, which is embarrassing in the case of a lady. if you direct him to the distance card twenty feet away, and find that he can see every one down to and including the one marked xx, his vision is up to the standard for distance, and you know that he can have no astigmatism worth correcting, nor any near sight, as both of these affect vision for distance, but he may have far sight or old sight or both combined. you must find which it is. if, while he is still looking at the twenty-foot line, you place in front of the eyes a weak convex and he tells you he sees just as well with as without, it proves the existence of far-sight or hypermetropia, and the strongest convex that still leaves vision as good for distance as without any, corrects the manifest. but if the weak convex blurs it, it shows that there is some defect in focusing, if the near vision is below normal. you therefore know that you have a case of old sight or presbyopia, requiring the weakest convex to correct it, that will enable your customer to see the finest line on the near card at the required distance. the next customer that comes to be fitted with glasses can only see the line marked xl on the distance card at feet or about one-half of what he should see, which leads you to think that there is no far sight, for vision for distance is good except in very high degrees of this error. nor can there be old-sight, for vision for distance is good in old-sight until after the fifty-fifth year, but it can be near sight (myopia) or astigmatism, or both. we next try the near card and find that even the finest line can be seen clearly if held sufficiently close to the eyes. we now know that this is a case of near sight, and we must fit them with glasses for distance. the weakest concave that will enable him to see the line that should be seen on the distance card at feet is the proper one to give him for use.--_the optician._ * * * * * charles goodyear. charles goodyear was born in new haven, december , . he was the son of amasa goodyear, and the eldest among six children. his father was quite proud of being a descendant of stephen goodyear, one of the founders of the colony of new haven in . amasa goodyear owned a little farm on the neck of land in new haven which is now known as oyster point, and it was here that charles spent the earliest years of his life. when, however, he was quite young, his father secured an interest in a patent for the manufacture of ivory buttons, and looking for a convenient location for a small mill, settled at naugatuck, conn., where he made use of the valuable water power that is there. aside from his manufacturing, the elder goodyear ran a farm, and between the two lines of industry kept young charles pretty busy. in , charles left his home and went to philadelphia to learn the hardware business. he worked at this very industriously until he was twenty-one years old, and then, returning to connecticut, entered into partnership with his father at the old stand in naugatuck, where they manufactured not only ivory and metal buttons, but a variety of agricultural implements, which were just beginning to be appreciated by the farmers. in august of he was united in marriage with clarissa beecher, a woman of remarkable strength of character and kindness of disposition, and one who in after years was of the greatest assistance to the impulsive inventor. two years later he removed again to philadelphia, and there opened a hardware store. his specialties were the valuable agricultural implements that his firm had been manufacturing, and after the first distrust of home made goods had worn away--for all agricultural implements were imported from england at that time--he found himself established at the head of a successful business. this continued to increase until it seemed but a question of a few years until he would be a very wealthy man. between and he suddenly broke down in health, being troubled with dyspepsia. at the same time came the failure of a number of business houses that seriously embarrassed his firm. they struggled on, however, for some time, but were finally obliged to fail. the ten years that followed this were full of the bitterest struggles and trials to goodyear. under the law that then existed he was imprisoned time after time for debts, even while he was trying to perfect inventions that should pay off his indebtedness. between the years and he began to hear about gum elastic and very carefully examined every article that appeared in the newspapers relative to this new material. the roxbury rubber company, of boston, had been for some time experimenting with the gum, and believing that they had found means for manufacturing goods from it, had a large plant and were sending their goods all over the country. it was some of their goods that first attracted his attention. soon after this goodyear visited new york, and went at once to the store of the roxbury rubber company. while there, he examined with considerable care some of their life preservers, and it struck him that the tube used for inflation was not very perfect. he, therefore, on his return to philadelphia, made some tubes and brought them down to new york and showed them to the manager of the roxbury rubber company. this gentlemen was so pleased with the ingenuity that goodyear had shown in manufacturing these tubes, that he talked very freely with him and confessed to him that the business was on the verge of ruin, that the goods had to be tested for a year before they could tell whether they were perfect or not, and to their surprise, thousands of dollars worth of goods that they had supposed were all right were coming back to them, the gum having rotted and made them so offensive that it was necessary to bury them in the ground to get them out of the way. goodyear at once made up his mind to experiment on this gum and see if he could not overcome its stickiness. he, therefore, returned to philadelphia, and, as usual, met a creditor, who had him arrested and thrown into prison. while there, he tried his first experiments with india rubber. the gum was very cheap then, and by heating it and working it in his hands, he managed to incorporate in it a certain amount of magnesia which produced a beautiful white compound and appeared to take away the stickiness. he therefore thought he had discovered the secret, and through the kindness of friends was put in the way of further perfecting his invention at a little place in new haven. the first thing that he made here was shoes, and he used his own house for grinding room, calender room, and vulcanizing department, and his wife and children helped to make up the goods. his compound at this time was india rubber, lampblack, and magnesia, the whole dissolved in turpentine and spread upon the flannel cloth which served as the lining for the shoes. it was not long, however, before he discovered that the gum, even treated this way, became sticky, and then those who had supplied the money for the furtherance of these experiments, completely discouraged, made up their minds that they could go no further, and so told the inventor. [illustration: charles goodyear.] he, however, had no mind to stop here in his experiments, but, selling his furniture and placing his family in a quiet boarding place, he went to new york, and there, in an attic, helped by a friendly druggist, continued his experiments. his next step in this line was to compound the rubber with magnesia and then boil it in quicklime and water. this appeared to really solve the problem, and he made some beautiful goods. at once it was noised abroad that india rubber had been so treated that it lost its stickiness, and he received medals and testimonials and seemed on the high road to success, till one day he noticed that a drop of weak acid, falling on the cloth, neutralized the alkali, and immediately the rubber was soft again. to see this, with his knowledge of what rubber should do, proved to him at once that his process was not a successful one. he therefore continued experimenting, and after preparing his mixtures in his attic in new york, would walk three miles to the mill of a mr. pike, at greenwich village, and there try various experiments. in the line of these, he discovered that rubber, dipped in nitric acid, formed a surface cure, and he made a great many goods with this acid cure which were spoken of, and which even received a letter of commendation from andrew jackson. the constant and varied experiments that goodyear went through with affected his health more or less, and at one time he came very near being suffocated by gas generated in his laboratory. that he did not die then everybody knows, but he was thrown then into a fever by the accident and came very near losing his life. it was there that he formed an acquaintance with dr. bradshaw, who was very much pleased with the samples of rubber goods that he saw in goodyear's room, and when the doctor went to europe he took them with him, where they attracted a great deal of attention, but beyond that nothing was done about them. now that he appeared to have success, he found no difficulty in obtaining a partner, and together the two gentlemen fitted up a factory and began to make clothing, life preservers, rubber shoes, and a great variety of rubber goods. they also had a large factory, with special machinery, built at staten island, where he removed his family and again had a home of his own. just about this time, when everything looked bright, the great panic of - came, and swept away the entire fortune of his associate and left goodyear without a cent, and no means of earning one. his next move was to go to boston, where he became acquainted with j. haskins, of the roxbury rubber company, and found in him a firm friend, who loaned him money and stood by him when no one would have anything to do with the visionary inventor. mr. chaffee was also exceedingly kind and ever ready to lend a listening ear to his plans, and to also assist him in a pecuniary way. it was about this time that it occurred to mr. chaffee that much of the trouble that they had experienced in working india rubber might come from the solvent that was used. he therefore invented a huge machine for doing the mixing by mechanical means. the goods that were made in this way were beautiful to look at, and it appeared, as it had before, that all difficulties were overcome. goodyear discovered a new method for making rubber shoes and got a patent on it, which he sold to the providence company, in rhode island. the secret of making the rubber so that it would stand heat and cold and acids, however, had not been discovered, and the goods were constantly growing sticky and decomposing and being returned. in he, for the first time, met nathaniel hayward, who was then running a factory in woburn. some time after this goodyear himself moved to woburn, all the time continuing his experiments. he was very much interested in hayward's sulphur experiments for drying rubber, but it appears that neither of them at that time appreciated the fact that it needed heat to make the sulphur combine with the rubber and to vulcanize it. the circumstances attending the discovery of his celebrated process is thus described by mr. goodyear himself in his book, "gum elastic." it will be observed that he makes use of the third person in all references to himself: "in the summer of he became acquainted with mr. nathaniel hayward, of woburn, mass., who had been employed as the foreman of the eagle company at woburn, where he had made use of sulphur by impregnating the solvent with it. it was through him that the writer (charles goodyear, who makes use all through his book of the third person) received the first knowledge of the use of sulphur as a drier of gum elastic. "mr. hayward was left in possession of the factory which was abandoned by the eagle company. soon after this it was occupied by the writer, who employed him for the purpose of manufacturing life preservers and other articles by the acid gas process. at this period he made many novel and useful applications of this substance. among other fancy articles he had newspapers printed on the gum elastic drapery, and the improvement began to be highly appreciated. he therefore now entered, as he thought, upon a successful career for the future. a far different result awaited him. "it was supposed by others as well as himself that a change was wrought through the mass of the goods acted upon by the acid gas, and that the whole body of the article was made better than the native gum. the surface of the goods really was so, but owing to the eventual decomposition of the goods beneath the surface, the process was pronounced by the public a complete failure. thus instead of realizing the large fortune which by all acquainted with his prospects was considered certain, his whole invention would not bring him a week's living. "he was obliged for the want of means to discontinue manufacturing, and mr. hayward left his employment. the inventor now applied himself alone, with unabated ardor and diligence, to detect the cause of his misfortune and if possible to retrieve the lost reputation of his invention. on one occasion he made some experiments to ascertain the effect of heat upon the same compound that had decomposed in the articles previously manufactured, and was surprised to find that the specimen, being carelessly brought in contact with a hot stove, charred like leather. he endeavored to call the attention of his brother as well as some other individuals who were present, and who were acquainted with the manufacture of gum elastic, to this effect as remarkable and unlike any before known, since gum elastic always melted when exposed to a high degree of heat. the occurrence did not at the time appear to them to be worthy of notice. it was considered as one of the frequent appeals that he was in the habit of making in behalf of some new experiment. he, however, directly inferred that if the process of charring could be stopped at the right point, it might divest the gum of its native adhesiveness throughout, which would make it better than the native gum. "he made another trial of heating a similar fabric, before an open fire. the same effect, that of charring the gum, followed, but there were further and very satisfactory indications of ultimate success in producing the desired result, as upon the edge of the charred portions of the fabric there appeared a line, or border, that was not charred, but perfectly cured. "these facts have been stated precisely as they occurred in reference to the acid gas, as well as the vulcanizing process. "the incidents attending the discovery of both have a strong resemblance, so much so they may be considered parallel cases. it being now known that the results of the vulcanizing process are produced by means and in a manner which would not have been anticipated from any reasoning on the subject, and that they have not yet been satisfactorily accounted for, it has been sometimes asked, how the inventor came to make the discovery? the answer has already been given. it may be added that he was many years seeking to accomplish this object, and that he allowed nothing to escape his notice that related to the subject. like the falling of an apple, it was suggestive of an important fact to one whose mind was previously prepared to draw an inference from any occurrence which might favor the object of his research. while the inventor admits that these discoveries were not the results of scientific chemical investigations, _he is not willing to admit that they were the result of what is commonly termed accident_; he claims them to be the result of the closest application and observation. "the discoloring and charring of the specimens proved nothing and discovered nothing of value, but quite the contrary, for in the first instance, as stated in the acid gas improvement, the specimen acted upon was thrown away as worthless and left for some time; in the latter instance, the specimen that was charred was in like manner disregarded by others. "it may, therefore, be considered as one of those cases where the leading of the creator providentially aids his creatures, by what are termed 'accidents,' to attain those things which are not attainable by the powers of reasoning he has conferred on them." now that goodyear was sure that he had the key to the intricate puzzle that he had worked over for so many years, he began at once to tell his friends about it and to try to secure capital, but they had listened to their sorrow so many times that his efforts were futile. for a number of years be struggled and experimented and worked along in a small way, his family suffering with himself the pangs of the extremest poverty. at last he went to new york and showed some of his samples to william ryder, who, with his brother emory, at once appreciated the value of the discovery and started in to manufacturing. even here goodyear's bad luck seemed to follow him, for the ryder bros. failed and it was impossible to continue the business. he had, however, started a small factory at springfield, mass., and his brother-in-law, mr. de forest, who was a wealthy woolen manufacturer, took ryder's place, and the work of making the invention practical was continued. in it was so far perfected that goodyear felt it safe to take out a patent. the factory at springfield was run by his brothers, nelson and henry. in henry started one in naugatuck, and in introduced mechanical mixing in place of the mixture by the use of solvents. in the year goodyear went to europe, a trip that he had long planned, and saw hancock, then in the employ of charles macintosh & co. hancock admitted in evidence that the first piece of vulcanized rubber he ever saw came from america, but claimed to have reinvented vulcanization and secured patents in great britain, but it is _a remarkable fact_ that charles goodyear's french patent was the first publication in europe of this discovery. in a french company were licensed by mr. goodyear to make shoes, and a great deal of interest was felt in the new business. in the french emperor gave to charles goodyear the grand medal of honor and decorated him with the cross of the legion of honor in recognition of his services as a public benefactor, but the french courts subsequently set aside his french patents on the ground of the importation of vulcanized goods from america by licenses under the united states patents. he died july , , at the fifth avenue hotel, new york city.--_india rubber world_. * * * * * [continued from supplement, no. , page .] the electromagnet. [footnote: lectures delivered before the society of arts, london, . from the journal of the society.] by professor silvanus p. thompson, d. sc., b.a., m.i.e.e. iii. researches of professor hughes. [illustration: fig. .--hughes' electromagnet.] his object was to find out the best form of electromagnet, the best distance between the poles, and the best form of armature for the rapid work required in hughes' printing telegraphs. one word about hughes' magnets. this diagram (fig. ) shows the form of the well known hughes' electromagnet. i feel almost ashamed to say those words "well known," because on the continent everybody knows what you mean by a hughes' electromagnet. in england scarcely anyone knows what you mean. englishmen do not even know that professor hughes has invented a special form of electromagnet. hughes' special form is this: a permanent steel magnet, generally a compound one, having soft iron pole pieces, and a couple of coils on the pole pieces only. as i have to speak of hughes' special contrivance among the mechanisms that will occupy our attention later on, i only now refer to this magnet in one particular. if you wish a magnet to work rapidly, you will secure the most rapid action, not when the coils are distributed all along, but when they are heaped up near, not necessarily entirely on, the poles. hughes made a number of researches to find out what the right length and thickness of these pole pieces should be. it was found an advantage not to use too thin pole pieces, otherwise the magnetism from the permanent magnet did not pass through the iron without considerable reluctance, being choked by insufficiency of section: also not to use too thick pieces, otherwise they presented too much surface for leakage across from one to the other. eventually a particular length was settled upon, in proportion about six times the diameter, or rather longer. in the further researches that hughes made he used a magnet of shorter form, not shown here, more like those employed in relays, and with an armature from to millimeters thick, centimeter wide and centimeters long. the poles were turned over at the top toward one another. hughes tried whether there was any advantage in making those poles approach one another, and whether there was any advantage in having as long an armature as centimeters. he tried all the different kinds, and plotted out the results of observations in curves, which could be compared and studied. his object was to ascertain the conditions which would give the strongest pull, not with a steady current, but with such currents as were required for operating his printing telegraph instruments; currents which lasted but one to twenty hundredths of a second. he found it was decidedly an advantage to shorten the length of the armature, so that it did not protrude far over the poles. in fact, he got a sufficient magnetic circuit to secure all the attractive power that he needed, without allowing as much chance of leakage as there would have been had the armature extended a longer distance over the poles. he also tried various forms of armature having very various cross sections. position and form of armature. in one of du moncel's papers on electromagnets[ ] you will also find a discussion on armatures, and the best forms for working in different positions. among other things in du moncel you will find this paradox: that whereas using a horseshoe magnet with fat poles, and a flat piece of soft iron for armature, it sticks on far tighter when put on edgeways; on the other hand, if you are going to work at a distance, across air, the attraction is far greater when it is set flatways. i explained the advantage of narrowing the surfaces of contact by the law of traction, b², coming in. why should we have for action at a distance the greater advantage from placing the armature flatway to the poles? it is simply that you thereby reduce the reluctance offered by the air gap to the flow of the magnetic lines. du moncel also tried the difference between round armatures and flat ones, and found that a cylindrical armature was only attracted about half as strongly as a prismatic armature having the same surface when at the same distance. let us examine this fact in the light of the magnetic circuit. the poles are flat. you have at a certain distance away a round armature; there is a certain distance between its nearest side and the polar surfaces. if you have at the same distance away a flat armature having the same surface, and, therefore, about the same tendency to leak, why do you get a greater pull in this case than in that? i think it is clear that if they are at the same distance away, giving the same range of motion, there is a greater magnetic reluctance in the case of the round armature, although there is the same periphery, because, though the nearest part of the surface is at the prescribed distance, the rest of the under surface is farther away; so that the gain found in substituting an armature with a flat surface is a gain resulting from the diminution in the resistance offered by the air gap. [footnote : "la lumiere electrique," vol. ii.] pole pieces on horseshoe magnets. another of du moncel's researches[ ] relates to the effect of polar projections or shoes--movable pole pieces, if you like--upon a horseshoe electromagnet. the core of this magnet was of round iron centimeters in diameter, and the parallel limbs were centimeters long and centimeters apart. the shoes consisted of two flat pieces of iron slotted out at one end, so that they could be slid along over the poles and brought nearer together. the attraction exerted on a flat armature across air gaps millimeters thick was measured by counterpoising. exciting this electromagnet with a certain battery, it was found that the attraction was greatest when the shoes were pushed to about millimeters, or about one-quarter of the interpolar distance, apart. the numbers were as follows: distance between shoes. attraction, millimeters. in grammes. , , [footnote : "la lumiere electrique," vol. iv., p. .] with a stronger battery the magnet without shoes had an attraction of grammes, but with the shoes millimeters apart, , grammes. when one pole only was employed, the attraction, which was grammes without a shoe, was _diminished_ by adding a shoe to grammes! contrast between electromagnets and permanent magnets. now i want particularly to ask you to guard against the idea that all these results obtained from electromagnets are equally applicable to permanent magnets of steel; they are not, for this simple reason. with an electromagnet, when you put the armature near, and make the magnetic circuit better, you not only get more magnetic lines going through that armature, but you get more magnetic lines going through the whole of the iron. you get more magnetic lines round the bend when you put an armature on to the poles, because you have a magnetic circuit of less reluctance with the same external magnetizing power in the coils acting around it. therefore, in that case, you will have a greater magnetic flux all the way round. the data obtained with the electromagnet (fig. ), with the exploring coil, c, on the bend of the core, where the armature was in contact, and when it was removed are most significant. when the armature was present it multiplied the total magnetic flow tenfold for weak currents and nearly threefold for strong currents. but with a steel horseshoe, magnetized once for all, the magnetic lines that flow around the bend of the steel are a fixed quantity, and, however much you diminish the reluctance of the magnetic circuit, you do not create or evoke any more. when the armature is away the magnetic lines arch across, not at the ends of the horseshoe only, but from its flanks; the whole of the magnetic lines leaking somehow across the space. where you have put the armature on, these lines, instead of arching out into space as freely as they did, pass for the most part along the steel limbs and through the iron armature. you may still have a considerable amount of leakage, but you have not made one line more go through the bent part. you have absolutely the same number going through the bend with the armature off as with the armature on. you do not add to the total number by reducing the magnetic reluctance, because you are not working under the influence of a constantly impressed magnetizing force. by putting the armature on to a steel horseshoe magnet you only _collect_ the magnetic lines, you do not _multiply_ them. this is not a matter of conjecture. a group of my students have been making experiments in the following way: they took this large steel horseshoe magnet (fig. ), the length of which, from end to end, through the steel, is ½ inches. a light, narrow frame was constructed so that it could be slipped on over the magnet, and on it were wound turns of fine wire, to serve as an exploring coil. the ends of this coil were carried to a distant part of the laboratory, and connected to a sensitive ballistic galvanometer. the mode of experimenting is as follows: the coil is slipped on over the magnet (or over its armature) to any desired position. the armature of the magnet is placed gently upon the poles, and time enough is allowed to elapse for the galvanometer needle to settle to zero. the armature is then suddenly detached. the first swing measures the change, due to removing the armature, in the number of magnetic lines that pass through the coil in the particular position. [illustration: fig. .--experiment with permanent magnet.] i will roughly repeat the experiment before you: the spot of light on the screen is reflected from my galvanometer at the far end of the table. i place the exploring coil just over the pole, and slide on the armature; then close the galvanometer circuit. now i detach the armature, and you observe the large swing. i shift the exploring coil, right up to the bend; replace the armature; wait until the spot of light is brought to rest at the zero of the scale. now, on detaching the armature, the movement of the spot of light is quite imperceptible. in our careful laboratory experiments, the effect was noticed inch by inch all along the magnet. the effect when the exploring coil was over the bend was not as great as - th part of the effect when the coil was hard up to the pole. we are, therefore, justified in saying that the number of magnetic lines in a permanently magnetized steel horseshoe magnet is not altered by the presence or absence of the armature. you will have noticed that i always put on the armature gently. it does not do to slam on the armature; every time you do so, you knock some of the so-called permanent magnetism out of it. but you may pull off the armature as suddenly as you like. it does the magnet good rather than harm. there is a popular superstition that you ought never to pull off the keeper of a magnet suddenly. on investigation, it is found that the facts are just the other way. you may pull off the keeper as suddenly as you like, but you should never slam it on. from these experimental results i pass to the special design of electromagnets for special purposes. electromagnets for maximum traction. these have already been dealt with in the preceding lecture; the characteristic feature of all the forms suitable for traction being the compact magnetic circuit. several times it has been proposed to increase the power of electromagnets by constructing them with intermediate masses of iron between the central core and the outside, between the layers of windings. all these constructions are founded on fallacies. such iron is far better placed either right inside the coils or right outside them, so that it may properly constitute a part of the magnetic circuit. the constructions known as camacho's and cance's, and one patented by mr. s.a. varley, in , belonging to this delusive order of ideas, are now entirely obsolete. another construction which is periodically brought forward as a novelty is the use of iron windings of wire or strip in place of copper winding. the lower electric conductivity of iron, as compared with copper, makes such a construction wasteful of exciting power. to apply equal magnetizing power by means of an iron coil implies the expenditure of about six times as many watts as need be expended if the coil is of copper. electromagnets for maximum range of attraction. we have already laid down the principle which will enable us to design electromagnets to act at a distance. we want our magnet to project, as it were, its force across the greatest length of air gap. clearly, then, such a magnet must have a very large magnetizing power, with many ampere turns upon it, to be able to make the required number of magnetic lines pass across the air resistance. also it is clear that the poles must not be too close together for its work, otherwise the magnetic lines at one pole will be likely to curl round and take short cuts to the other pole. there must be a wider width between the poles than is desirable in electromagnets for traction. electromagnets of minimum weight. in designing an apparatus to put on board a boat or a balloon, where weight is a consideration of primary importance, there is again a difference. there are three things that come into play--iron, copper, and electric current. the current weighs nothing, therefore, if you are going to sacrifice everything else to weight, you may have comparatively little iron, but you must have enough copper to be able to carry the electric current; and under such circumstances you must not mind heating your wires nearly red hot to pass the biggest possible current. provide as little copper as you conveniently can, sacrificing economy in that case to the attainment of your object; but, of course, you must use fireproof material, such as asbestos, for insulating, instead of cotton or silk. a useful guiding principle. in all cases of design there is one leading principle which will be found of great assistance, namely, that a magnet always tends so to act as though it tried to diminish the length of its magnetic circuit. it tries to grow more compact. this is the reverse of that which holds good with an electric current. the electric circuit always tries to enlarge itself, so as to inclose as much space as possible, but the magnetic circuit always tries to make itself as compact as possible. armatures are drawn in as near as can be, to close up the magnetic circuit. many two-pole electromagnets show a tendency to bend together when the current is turned on. one form in particular, which was devised by ruhmkorff for the purpose of repeating faraday's celebrated experiment on the magnetic rotation of polarized light, is liable to this defect. indeed, this form of electromagnet is often designed very badly, the yoke being too thin, both mechanically and magnetically, for the purpose which it has to fulfill. here is a small electric bell, constructed by wagener, of wiesbaden, the construction of which illustrates this principle. the electromagnet, a horseshoe, lies horizontally; its poles are provided with protruding curved pins of brass. through the armature are drilled two holes, so that it can be hung upon the two brass pins; and when so hung up it touches the ends of the iron cores just at one edge, being held from more perfect contact by a spring. there is no complete gap, therefore, in the magnetic circuit. when the current comes and applies a magnetizing power, it finds the magnetic circuit already complete in the sense that there are no absolute gaps. but the circuit can be bettered by tilting the armature to bring it flat against the polar ends, that being indeed the mode of motion. this is a most reliable and sensitive pattern of bell. [illustration: fig. .--electromagnetic pop-gun.] _electromagnetic pop-gun._--here is another curious illustration of the tendency to complete the magnetic circuit. here is a tubular electromagnet (fig. ), consisting of a small bobbin, the core of which is an iron tube about two inches long. there is nothing very unusual about it; it will stick on, as you see, to pieces of iron when the current is turned on. it clearly is an ordinary electromagnet in that respect. now suppose i take a little round rod of iron, about an inch long, and put it into the end of the tube, what will happen when i turn on my current? in this apparatus as it stands, the magnetic circuit consists of a short length of iron, and then all the rest is air. the magnetic circuit will try to complete itself, not by shortening the iron, but by _lengthening_ it; by pushing the piece of iron out so as to afford more surface for leakage. that is exactly what happens; for, as you see, when i turn on the current, the little piece of iron shoots out and drops down. you see that little piece of iron shoot out with considerable force. it becomes a sort of magnetic popgun. this is an experiment which has been twice discovered. i found it first described by count du moncel, in the pages of _la lumiere electrique_, under the name of the "pistolet electromagnetique;" and mr. shelford bidwell invented it independently. i am indebted to him for the use of this apparatus. he gave an account of it to the physical society, in , but the reporter missed it, i suppose, as there is no record in the society's proceedings. electromagnets for use with alternating currents. when you are designing electromagnets for use with alternating currents, it is necessary to make a change in one respect, namely, you must so laminate the iron that internal eddy currents shall not occur; indeed, for all rapid-acting electromagnetic apparatus it is a good rule that the iron must not be solid. it is not usual with telegraphic instruments to laminate them by making up the core of bundles of iron plates or wires, but they are often made with tubular cores, that is to say, the cylindrical iron core is drilled with a hole down the middle, and the tube so formed is slit with a saw cut to prevent the circulation of currents in the substance of the tube. now when electromagnets are to be employed with rapidly alternating currents, such as are used for electric lighting, the frequency of the alternations being usually about periods per second, slitting the cores is insufficient to guard against eddy currents; nothing short of completely laminating the cores is a satisfactory remedy. i have here, thanks to the brush electric engineering company, an electromagnet of the special form that is used in the brush arc lamp when required for the purpose of working in an alternating current circuit. it has two bobbins that are screwed up against the top of an iron box at the head of the lamp. the iron slab serves as a kind of yoke to carry the magnetism across the top. there are no fixed cores in the bobbins, which are entered by the ends of a pair of yoked plungers. now in the ordinary brush lamp for use with a steady current, the plungers are simply two round pieces of iron tapped into a common yoke; but for alternate current working this construction must not be used, and instead a u-shaped double plunger is used, made up of laminated iron, riveted together. of course it is no novelty to use a laminated core; that device, first used by joule, and then by cowper, has been repatented rather too often during the past fifty years to be considered as a recent invention. the alternate rapid reversals of the magnetism in the magnetic field of an electromagnet, when excited by alternating electric currents, sets up eddy currents in every piece of undivided metal within range. all frames, bobbin tubes, bobbin ends, and the like, must be most carefully slit, otherwise they will overheat. if a domestic flat iron is placed on the top of the poles of a properly laminated electromagnet, supplied with alternating currents, the flat iron is speedily heated up by the eddy currents that are generated internally within it. the eddy currents set up by induction in neighboring masses of metal, especially in good conducting metals such as copper, give rise to many curious phenomena. for example, a copper disk or copper ring placed over the pole of a straight electromagnet so excited is violently repelled. these remarkable phenomena have been recently investigated by professor elihu thomson, with whose beautiful and elaborate researches we have lately been made conversant in the pages of the technical journals. he rightly attributes many of the repulsion phenomena to the lag in phase of the alternating currents thus induced in the conducting metal. the electromagnetic inertia, or self-inductive property of the electric circuit, causes the currents to rise and fall later in time than the electromotive forces by which they are occasioned. in all such cases the impedance which the circuit offers is made up of two things--resistance and inductance. both these causes tend to diminish the amount of current that flows, and the inductance also tends to delay the flow. electromagnets for quickest action. i have already mentioned hughes' researches on the form of electromagnet best adapted for rapid signaling. i have also incidentally mentioned the fact that where rapidly varying currents are employed, the strength of the electric current that a given battery can yield is determined not so much by the resistance of the electric circuit as by its electric inertia. it is not a very easy task to explain precisely what happens to an electric circuit when the current is turned on suddenly. the current does not suddenly rise to its full value, being retarded by inertia. the ordinary law of ohm in its simple form no longer applies; one needs to apply that other law which bears the name of the law of helmholtz, the use of which is to give us an expression, not for the final value of the current, but for its value at any short time, t, after the current has been turned on. the strength of the current after a lapse of a short time, t, cannot be calculated by the simple process of taking the electromotive force and dividing it by the resistance, as you would calculate steady currents. in symbols, helmholtz's law is: i_{t} = e/r ( - e^{-(r/l)t} ) in this formula i_{t} means the strength of the current after the lapse of a short time t; e is the electromotive force; r, the resistance of the whole circuit; l, its coefficient of self-induction; and _e_ the number . , which is the base of the napierian logarithms. let us look at this formula; in its general form it resembles ohm's law, but with a new factor, namely, the expression contained within the brackets. the factor is necessarily a fractional quantity, for it consists of unity less a certain negative exponential, which we will presently further consider. if the factor within brackets is a quantity less than unity, that signifies that i_{t} will be less than e ÷ r. now the exponential of negative sign, and with negative fractional index, is rather a troublesome thing to deal with in a popular lecture. our best way is to calculate some values, and then plot it out as a curve. when once you have got it into the form of a curve, you can begin to think about it, for the curve gives you a mental picture of the facts that the long formula expresses in the abstract. accordingly we will take the following case. let e = volts; r = ohm; and let us take a relatively large self-induction, so as to exaggerate the effect; say let l = quads. this gives us the following: ________________________________________ | | | | | t_{(sec.)} | e^{+(r/l)t} | i_{t} | --------------+--------------+---------| | | | | | | . | . | | | . | . | | | . | . | | | . | . | | | . | . | | | . | . | | | . | . | | | . | . | ---------------------------------------- in this case the value of the steady current as calculated by ohm's law is amperes, but helmholtz's law shows us that with the great self-induction which we have assumed to be present, the current, even at the end of seconds, has only risen up to within percent. of its final value; and only at the end of two minutes has practically attained full strength. these values are set out in the highest curve in fig. , in which, however, the further supposition is made that the number of spirals, s, in the coils of the electromagnet is , so that when the current attains its full value of amperes, the full magnetizing power will be si = . it will be noticed that the curve rises from zero at first steeply and nearly in a straight line, then bends over, and then becomes nearly straight again, as it gradually rises to its limiting value. the first part of the curve--that relating to the strength of the current after _very small_ interval of time--is the period within which the strength of the current is governed by inertia (i.e., the self-induction) rather than by resistance. in reality the current is not governed either by the self-induction or by the resistance alone, but by the ratio of the two. this ratio is sometimes called the "time constant" of the circuit, for it represents _the time_ which the current takes in that circuit to rise to a definite fraction of its final value. e = r = r = l = si + _..------------------------------- | . _ _--------- | . .---- | . .- in series | . .- | - | .: - : | .: . : | . : __- -:--------------------------- | . : _.- - : in parallel | . :. - : | . / : - : | . / - : |. / - : : |./. : : |/_____:_____________:____________________________ t fig. .--curves of rise of currents. this definite fraction is the fraction (e - )/e; or in decimals, . . all curves of rise of current are alike in general shape, they differ only in scale, that is to say, they differ only in the height to which they will ultimately rise, and in the time they will take to attain this fraction of their final value. _example ( )._--suppose e = ; r = ohms; l = . the final value of the current will be . amp. or milliamperes. then the time constant will be ÷ = - th sec. _example ( )._--the p.o. standard "a" relay has r = ohms; l = . . it works with . milliampere current, and therefore will work with daniell cells through a line of , ohms. under these circumstances the time constant of the instrument on short circuit is . sec. it will be noted that the time constant of a circuit can be reduced either by diminishing the self-induction or by increasing the resistance. in fig. the position of the time constant for the top curve is shown by the vertical dotted line at seconds. the current will take seconds to rise to . of its final value. this retardation of the rise of current is simply due to the presence of coils and electromagnets in the circuit; the current as it grows being retarded because it has to create magnetic fields in these coils, and so sets up opposing electromotive forces that prevent it from growing all at once to its full strength. many electricians, unacquainted with helmholtz's law, have been in the habit of accounting for this by saying that there is a lag in the iron of the electromagnet cores. they tell you that an iron core cannot be magnetized suddenly, that it takes time to acquire its magnetism. they think it is one of the properties of iron. but we know that the only true time lag in the magnetization of iron, that which is properly termed "viscous hysteresis," does not amount to any great percentage of the whole amount of magnetization, takes comparatively a long time to show itself, and cannot therefore be the cause of the retardation which we are considering. there are also electricians who will tell you that when magnetization is suddenly evoked in an iron bar, there are induction currents set up in the iron which oppose and delay its magnetization. that they oppose the magnetization is perfectly true, but if you carefully laminate the iron so as to eliminate eddy currents, you will find, strangely enough, that the magnetism rises still more slowly to its final value. for by laminating the iron you have virtually increased the self-inductive action, and increased the time constant of the circuit, so that the currents rise more slowly than before. the lag is not in the iron, but in the magnetizing current, and the current being retarded, the magnetization is of course retarded also. connecting coils for quickest action. now let us apply these most important though rather intricate considerations to the practical problems of the quick working of the electromagnet. take the case of an electromagnet forming some part of the receiving apparatus of a telegraph system in which it is desired to secure very rapid working. suppose the two coils that are wound upon the horseshoe core are connected together in series. the coefficient of self-induction for these two is four times as great as that of either separately; coefficients of self-induction being proportional to the square of the number of turns of wire that surround a given core. now if the two coils instead of being put in series are put in parallel, the coefficient of self-induction will be reduced to the same value as if there were only one coil, because half the line current (which is practically unaltered) will go through each coil. hence the time constant of the circuit when the coils are in parallel will be a quarter of that which it is when the coils are in series; on the other hand, for a given line current, the final magnetizing power of the two coils in parallel is only half what it would be with the coil in series. the two lower curves in fig. illustrate this, from which it is at once plain that the magnetizing power for very brief currents is greater when the two coils are put in parallel with one another than when they are joined in series. now this circumstance has been known for some time to telegraph engineers. it has been patented several times over. it has formed the theme of scientific papers, which have been read both in france and in england. the explanation generally given of the advantage of uniting the coils in parallel is, i think, fallacious; namely that the "extra currents" (i.e., currents due to self-induction) set up in the two coils are induced in such directions as tend to help one another when the coils are in series, and to neutralize one another when they are in parallel. it is a fallacy, because in neither case do they neutralize one another. whichever way the current flows to make the magnetism, it is opposed in the coils while the current is rising, and helped in the coils while the current is falling, by the so-called extra currents. if the current is rising in both coils at the same moment, then, whether the coils are in series or in parallel, the effect of self-induction is to retard the rise of the current. the advantage of parallel grouping is simply that it reduces the time constant. battery grouping for quickest action. one may consider the question of grouping the battery cells from the same point of view. how does the need for rapid working, and the question of time constant, affect the best mode of grouping the battery cells? the amateur's rule, which tells you to so arrange your battery that its internal resistance should be equal to the external resistance, gives you a result wholly wrong for rapid working. the supposed best arrangement will not give you (at the expense even of economy) the best result that might be got out of the given number of cells. let us take an example and calculate it out, and place the results graphically before our eyes in the form of curves. suppose the line and electromagnet have together a resistance of ohms, and that we have small daniell cells, each of electromotive force say volt, and of internal resistance ohms. also let the coefficient of self-induction of the electromagnet and circuit be quadrants. when all the cells are in series, the resistance of the battery will be ohms, the total resistance of the circuit ohms, and the full value of the current . ampere. when all the cells are in parallel, the resistance of the battery will be . ohm, the total resistance . ohms, and the full value of the current . ampere. according to the amateur rule of grouping cells so that internal resistance equals external, we must arrange the cells in parallels, each having cells in series, so that the internal resistance of the battery will be ohms, total resistance of circuit ohms, full value of current . ampere. now the corresponding time constants of the circuit in the three cases (calculated by dividing the coefficient of self-induction by the total resistance) will be respectively--in series, . sec.; in parallel, . sec.; grouped for maximum steady current, . sec. from these data we may now draw the three curves, as in fig. , wherein the abscissæ are the values of time in seconds and the ordinates the current. the faint vertical dotted lines mark the time constants in the three cases. it will be seen that when rapid working is required the magnetizing current will rise, during short intervals of time, more rapidly if all the cells are put in series than it will do if the cells are grouped according to the amateur rule. | | . | . | . | maximum . | output \ . | . | . | . : all in series | _-------------------:------------------------------ | .- - : | - - : | -: - : | / : - : all in parallel |. : . : _________-------- |- :__ : ---------- +-----------------------------:------------------------------- fig. .--curves of rise of current with different groupings of battery. when they are all put in series, so that the battery has a much greater resistance than the rest of the circuit, the current rises much more rapidly, because of the smallness of the time constant, although it never attains the same ultimate maximum as when grouped in the other way. that is to say, if there is self-induction as well as resistance in the circuit, the amateur rule does not tell you the best way of arranging the battery. there is another mode of regarding the matter which is helpful. self-induction, while the current is growing, acts as if there were a sort of spurious addition to the resistance of the circuit; and while the current is dying away it acts of course in the other way, as if there were a subtraction from the resistance. therefore you ought to arrange the battery so that the internal resistance is equal to the real resistance of the circuit, plus the spurious resistance during that time. but how much is the spurious resistance during that time? it is a resistance proportional to the time that has elapsed since the current was turned on. so then it comes to a question of the length of time for which you want to work it. what fraction of a second do you require your signal to be given in? what is the rate of the vibrator of your electric bell? suppose you have settled that point, and that the short time during which the current is required to rise is called t; then the apparent resistance at time t after the current is turned on is given by the formula: r_{t} = r × e^{(r/l)t} + ( e^{(r/l)t} - ) time constants of electromagnets. i may here refer to some determinations made by m. vaschy,[ ] respecting the coefficients of self-induction of the electromagnets of a number of pieces of telegraphic apparatus. of these i must only quote one result, which is very significant. it relates to the electromagnet of a morse receiver of the pattern habitually used on the french telegraph lines. l, in quadrants. bobbins, separately, without iron cores. . and . bobbins, separately, with iron cores. . and . bobbins, with cores joined by yoke, coils in series . bobbins, with armature resting on poles. . [footnote : "bulletin de la societe internationale des electriciens," .] it is interesting to note how the perfecting of the magnetic circuit increases the self-induction. thanks to the kindness of mr. preece, i have been furnished with some most valuable information about the coefficients of self-induction, and the resistance of the standard pattern of relays, and other instruments which are used in the british postal telegraph service, from which data one is able to say exactly what the time constants of those instruments will be on a given circuit, and how long in their case the current will take to rise to any given fraction of its final value. here let me refer to a very capital paper by mr. preece in an old number of the "journal of the society of telegraph engineers," a paper "on shunts," in which he treats this question, not as perfectly as it could now be treated with the fuller knowledge we have in about the coefficients of self-induction, but in a very useful and practical way. he showed most completely that the more perfect the magnetic circuit is--though of course you are getting more magnetism from your current--the more is that current retarded. mr. preece'e mode of experiment was extremely simple. he observed the throw of the galvanometer when the circuit which contained the battery and the electromagnet was opened by a key which at the same moment connected the electromagnet wires to the galvanometer. the throw of the galvanometer was assumed to represent the extra current which flowed out. fig. represents a few of the results of mr. preece's paper. +==========+ |=| |=| |=| |=| |=| \======= \======= =======/ ======= ======= | | | | | | | | | | | | | | | | | | | | | | | |--| | | | | | ======= ======= ======= /======= =======\ |=| |=| |=| |=| |=| +===========+ +==========+ +===== ======+ |=| |=| |=| |=| |=| |=| ======= =======/ b\======= =======/a a\======= =======/b | | | | | | | | | | | | | | | | | | | | | | | | | |--| | | | | | | | | | ======= ======= a======= =======b =======b =======a |=| |=| |=| |=| |=| |=| +==========+ +==========+ +====== =====+ fig. .--electromagnets of relay, and their effects. take from an ordinary relay a coil, with its iron core, half the electromagnet, so to speak, without any yoke or armature. connect it up as described, and observe the throw given to the galvanometer. the amount of throw obtained from the single coil was taken as unity, and all others were compared with it. if you join up two such coils as they are usually joined, in series, but without any iron yoke across the cores, the throw was . putting the iron yoke across the cores, to constitute a horseshoe form, was the throw; that is to say, the tendency of this electromagnet to retard the current was times as great as that of the simple coil. but when an armature was put over the top, the effect ran up to , . by the mere device of putting the coils in parallel, instead of in series, the , came down to , a little less than the quarter value which would have been expected. lastly, when the armature and yoke were both of them split in the middle, as is done in fact in all the standard patterns of the british postal telegraph relays, the throw of the galvanometer was brought down from to . relays so constructed will work excessively rapidly. mr. preece states that with the old pattern of relay having so much self-induction as to give a galvanometer throw of , , the speed of signaling was only from to words per minute, whereas, with the standard relays constructed on the new plan, the speed of signaling is from to words per minute. it is a very interesting and beautiful result to arrive at from the experimental study of these magnetic circuits. short cores _versus_ long cores. in considering the forms that are best for rapid action, it ought to be mentioned that the effects of hysteresis in retarding changes in the magnetization of iron cores are much more noticeable in the case of nearly closed magnetic circuits than in short pieces. electromagnets with iron armatures in contact across their poles will retain, after the current has been cut off, a very large part of their magnetism, even if the cores be of the softest of iron. but so soon as the armature is wrenched off, the magnetism disappears. an air gap in a magnetic circuit always tends to hasten demagnetizing. a magnetic circuit composed of a long air path and a short iron path demagnetizes itself much more rapidly than one composed of a short air path and a long iron path. in long pieces of iron the mutual action of the various parts tends to keep in them any magnetization that they may possess; hence they are less readily demagnetized. in short pieces, where these mutual actions are feeble or almost absent, the magnetization is less stable, and disappears almost instantly on the cessation of the magnetizing force. short bits and small spheres of iron have no magnetic memory. hence the cause of the commonly received opinion among telegraph engineers that for rapid work electromagnets must have short cores. as we have seen, the only reason for employing long cores is to afford the requisite length for winding the wire which is necessary for carrying the needful circulation of current to force the magnetism across the air gaps. if, for the sake of rapidity of action, length has to be sacrificed, then the coils must be heaped up more thickly on the short cores. the electromagnets in american patterns of telegraphic apparatus usually have shorter cores, and a relatively greater thickness of winding upon them, than those of european patterns. * * * * * electric erygmascope. the erygmascope is the name of an electric lighting apparatus designed for the examination of the strata of earth traversed by boring apparatus. it consists of a very powerful incandescent lamp inclosed in a metallic cylinder. one of the two semi-cylindrical sides constitutes the reflector, and the other, which is of thick glass, allows of the passage of the luminous rays, which thus illuminate with great brilliancy the strata of earth traversed by the instrument. the base, which is inclined at an angle of °, is an elliptical mirror, and the top, of straight section, is open in order to permit the observer standing at the mouth of the well, and provided with a powerful spyglass, to see in the mirror the image of the earth. the lamp is so mounted that its upwardly emitted rays are intercepted. the whole apparatus is suspended from a long cable, formed of two conducting wires, which winds around a windlass with metallic journals which are electrically insulated. these journals communicate, through the intermedium of two friction springs, with the conductors on the one hand and, on the other, with the poles of an automatic and portable battery. [illustration: the trouve erygmascope.] this permits of lowering and raising the apparatus at will, without derangement, and without its being necessary to interrupt the light and the observation.--_revue industrielle._ * * * * * a new electric ballistic target. the electrical target usually employed in determining velocities of projectiles consists of a wooden frame on which is strung a copper wire so as to make a continuous circuit arranged in parallel vertical lines about one inch or one and one half inches apart. it frequently happens that a projectile will pass through this target without breaking the circuit, either by squeezing between the wires or because, when last repaired, the target was short-circuited unnoticed, so that the cutting of the wires did not break the circuit. the repair of this target takes considerable time. _______________________________________________________ | { | +-------------__ --------------__---------------- } | | _ // \\ // \\ } { | | |_| || c_{ } || a || || || a { } | | p \\ // \\ // } { | +------------- --------------- ---------------- } | f { |_______________________________________________________} plan. p c =|= _________ |===| ========= a a ========| | s |========\_______/================= |spring | | | | | | | | |s_ | __| |__ __| ||| | | ___________|||______________| |_____________________ | | section. h / \+/ | | | | | | _____+_____ | | | w | | | |___________| besides these objections to this target, another and more serious one is the irregularity in the manner of breaking the circuit. it has been proved that times required for a flat headed and an ogival headed projectile to rupture the current are very different. to remedy these defects a new and very ingenious target has been devised and used with great success at the united states military academy at west point. the top of the target is a wooden strip, f, on the upper side of which are screwed strips of copper, a a, about / in. wide, and / in. thick. the connection between two adjoining strips is made by a copper cartridge, c, which is dropped in a hole in the frame bored to receive it. this cartridge is the one used in the springfield rifle. inside the cartridge is a spiral spring, s, which, acting on the bottom of the hole and the head of the cartridge, tends to make the latter spring up, and so break the circuit. to the hook, h, which is attached to the cartridge, is suspended, by means of a string, the lead weight, w, thus drawing down the cartridge and making the circuit between a and a'. all the weights being suspended the current comes in through the post, p, passes along the copper strips and out of the corresponding post on the other end. on firing the projectile cuts a string, and the spring at once causes the cartridge to spring up, thus breaking the circuit. it is not possible for the projectile to squeeze between the strings and not break the current, for in so doing the cartridge is tipped slightly, which is sufficient, as it breaks the current on one side. this target is used in connection with the boulenge chronograph. two targets are established at a known distance apart, say ft., and the time required for the projectile to pass over this distance is determined by finding the difference in the time of cutting of the two targets, by finding the difference in the time of falling of the two rods, caused by the demagnetization of two electromagnets in the same circuit with the targets. by means of a disjunctor both rods are dropped at the same time, the shorter one releasing a knife blade which makes a cut on the longer one. now both rods are hung from the magnets again and the gun is fired. the projectile passes through the first target, breaks the circuit, demagnetizes the magnet of the longer rod, and it begins to fall. on passing through the second target, the projectile causes the shorter rod to fall. this releases the knife blade, and a second cut is made. the time corresponding to the distance between these cuts is the time the longer rod was falling before the second rod began to fall or the time between the cutting of the two targets by the projectile. the distance between the cuts is measured, and the time corresponding to it can easily be found. then the velocity of the projectile is equal to /t. to repair this target, strings are prepared in advance of suitable length and looped at both ends, so that by placing the hook of the cartridge in one loop and that of the weight in the other the repair is quickly made. this target has been used on the west point proving ground to determine velocities over distances of ft. interval to distances of only ft. interval, and has given most satisfactory results. * * * * * [continued from supplement, no. , page .] the outlook for applied entomology. [footnote: address of dr. c.v. riley at the annual meeting of the association of economic entomologists, champaign, ills., november to , .] legislation. the amount of legislation in different countries that has of late years been deemed necessary or sufficiently important, in view of injurious insects, is a striking evidence of the increased attention paid to applied entomology; and while modern legislation of this kind has been, on the whole, far more intelligent than similar efforts in years gone by, many of the laws passed have nevertheless been unwise, futile, and impracticable, and even unnecessarily oppressive to other interests. the chief danger here is the intervention of politics or political methods. expert counsel should guide our legislators and the steps taken should be thorough in order to be effective. we have had of late years in germany very good evidence of the excellent results flowing from thorough methods, and the recent legislation in massachusetts against the gypsy moth (_ocneria dispar_), which at one time threatened to become farcical, has, fortunately, proved more than usually successful; the commission appointed to deal with the subject having worked with energy and followed competent advice. publication. on the question of publication of the results of our labors it is perhaps premature to dwell at length. each of the experiment stations is publishing its own bulletins and reports quite independently of the others, but after a uniform plan recommended by the association with which we meet here; and with but one exception that has come to my notice, another important recommendation of the same association--that these publications shall be void of all personal matter--has been kept in mind. the national bureau of experiment stations at washington is doing what it can with the means at command to further the general work by issuing the experiment station record, devoted chiefly to digests of the state station bulletins. there is a serious question in my mind as to the utility of state digests by the national department of results already published extensively by the different states and distributed under government frank to all similar institutions and to whomsoever is interested enough to ask for them. such digests may or may not be intelligently made, and, even under the most favorable circumstances, will hardly serve any other purpose than helping to the reference to the original articles, and this could undoubtedly be done more satisfactorily to the stations and to the people at large by general and classified indices to all the state documents, made as full as possible and issued at stated intervals. only a small proportion of the bulletins have been so far noticed by digest in this record, with no particular rule, so far as i can see, in the selection. in point of fact, those will be most apt to be noticed whose authors can find time to themselves send or make for the purpose their own abstracts. this is, perhaps, inevitable under present arrangements. complete and satisfactory digests of all, if intelligent and critical, imply a far greater force than is at present at prof. atwater's command. under these circumstances, it would seem wiser to devote all the energies of the bureau to digests of the similar literature of other countries, which would be of immense advantage to our people and to the different station workers. judging from the recommendations and resolutions of the general association, this is the view very generally held, but except in chemistry and special industries like that of beet sugar, very little of that kind of work has yet been attempted. what is true of the station publications in general is equally true of special publications. as entomologist of the department, i have been urged to bring together, at stated intervals, digests of the entomological publications of the different stations. such digests to be of any value, however, should also be critical, and it were a thankless task for any one to be critic or censor even of that which needs correction or criticism. moreover, to do this work intelligently would require increase of the divisional force, which at present is more advantageously employed, for, as already intimated, i should have great doubts of the utility of these digests. i believe, however, that the division should strive for such increase of means as would justify the periodic publication, either independently or as a part of the department record, of general and classified indices to the entomological matter of the station bulletins, and should work more and more toward giving results from other parts of the world. this could, perhaps, best be done by titles of subject and of author so spaced and printed on stout paper that they could be cut and used in the ordinary card catalogue. the recipient could cut and systematically place the titles as fast as received. as to the character of the matter of the entomological bulletins, it will inevitably be influenced by the needs and demands of the people of the respective states, and while originality should be kept in mind, there must needs be in the earlier years of the work much restatement of what is already well known. that some results have been published of work which reflects no particular credit upon our calling is a mere incident of the new positions created. yet we may expect marked improvement from year to year in this direction, and without being invidious, i would cite those of prof. gillette's on his spraying experiments and on the plum curculio and plum gouger, as models of what such bulletins should be. although the resolution offered at our last meeting by prof. cook, to the effect that purely descriptive matter should be excluded from the station bulletins, met with no favor, but was laid on the table, by the general association, i am in full sympathy with this position and am strongly of the opinion that in the ordinary bulletins such purely technical and descriptive matter should be reduced to the necessary minimum consistent with clearness of statement and accuracy, and that if it is desired, on the part of the station entomologists, to issue technical and descriptive papers, a separate series of bulletins were better instituted for this class of matter. finally, for results which it is desired to promptly get before the people, the agricultural press is at our disposal, and so far as the entomological work of the department of agriculture is concerned, the periodical bulletin, _insect life_, was established for this purpose. its columns are open to all station workers, and i would here appeal to the members of the association to help make it, as far as possible, national, by sending brief notes and digests of their work as it progresses. hitherto we have been unable to make as much effort in this direction as we desired, but in future it is our hope to make the bulletin, as far as possible, a national medium through which the results of work done in all parts of the country may quickly be put on record and distributed, not only to all parts of our own country, but to all parts of the world. the rapid growth and development of the national department and the multiplication of its divisions have necessitated special modes of publication and rendered the annual report almost an anachronism so far as it pretends to be what it at one time was--a pretty complete report of the scientific and other work of the department. the attempts which i have made through the proper authorities to get congress to order more pretentious monographic works in quarto volume similar to those issued by other departments of the government have not met with encouragement, and in this direction many of the stations will, let us hope, be able to do better. co-operation. every other subject that might be considered on this occasion must be subordinate to the one great question of co-operation. with the large increase of actual workers in our favorite field, distributed all over the country, the necessity for some co-operation and co-ordination must be apparent to every one. just how this should be brought about or in what direction we may work toward it, will be for this association in its deliberations to decide. nor will i venture to anticipate the deliberations and conclusions of the special committee appointed to take the matter into consideration, beyond the statement that there are many directions in which we can adopt plans for mutual benefit. take, for instance, the introduction and dissemination of parasites. how much greater will be the chance of success in any particular case if we have all the different station entomologists interested in some specific plan to be carried out in co-operation with the national department, which ought to have better facilities of introducing specimens to foreign countries or to different sections of our own country than any of the state stations. let us suppose that the fruit growers of one section of the country, comprising several states in area, need the benefit in their warfare against any particularly injurious insect of such natural enemy or enemies as are known to help the fruit growers of some other section. there will certainly be much greater chances of success in the carrying out of any scheme of introduction if all the workers in the one section may be called upon through some central or national body to help in the introduction and disposition of the desired material into the other section. or, take the case of the boll worm investigation already alluded to. the chances of success would be much greater if the entomologists in all the states interested were to give some attention to such lepidopterous larvæ as are found to be affected with contagious diseases and to follow out some specific plan of cultivating and transmitting them to the party or parties with whom the actual trials are intrusted. the argument applies with still greater force to any international efforts. i need hardly multiply instances. there is, it is true, nothing to prevent any individual station entomologist from requesting co-operation of the other stations, nor is there anything to prevent the national department from doing likewise; but in all organization results are more apt to flow from the power to direct rather than from mere liberty to request or to plead. the station entomologist may be engrossed in some line of research which he deems of more importance to the people of his state, and may resent being called upon to divert his energies; and with no central or national power to decide upon plans of co-operation for the common weal, we are left to voluntary methods, mutually devised, and it is here that this association can, it seems to me, most fully justify its organization. and this brings me to the question of the department and the stations. immediately connected with the question of co-operation is the relation of the national department of agriculture and the state experiment stations. the relation, instead of being vital and authoritative, is, in reality, a subordinate one. many persons interested in the advancement of agriculture foresaw the advantage of having experiment stations attached to the state agricultural colleges founded under the morrill act of ; but i think that in the minds of most persons the establishment of these stations implied some such connection with the national department as that outlined in an address on agricultural advancement in the united states, which i had the honor to deliver in before the national agricultural congress, at rochester, and in which the following language was used: "in the light of the past history of the german experimental stations and their work, or of that in our own state of connecticut, the expediency of purchasing an experimental farm of large dimensions in the vicinity of washington is very questionable. there can be no doubt, however, of the value of a good experimental station there that shall have its branches in every state of the union. the results to flow from such stations will not depend upon the number of acres at command, and it will be far wiser and more economical for the commissioner to make each agricultural college that accepted the government endowment auxiliary to the national bureau, so that the experimental farm that is now, or should be, connected with each of these institutions might be at its service and under the general management of the superintendent of the main station. there is reason to believe that the directors of these colleges would cheerfully have them constituted as experimental stations under the direction of the department, and thus help to make it really national--the head of a vast system that should ramify through all parts of the land.... "with the different state agricultural colleges, and the state agricultural societies, or boards, we have every advantage for building up a national bureau of agriculture worthy of the country and its vast productive interests, and on a thoroughly economical basis, such as that of prussia, for instance." in short, the view in mind was something in the nature of that which has since been adopted by our neighbors of the north, where there is a central or national station or farm at ottawa and sub-stations or branch farms at nappan, nova scotia, brandon, manitoba, indian head, n.w.t., and agassiz, british columbia, all under the able direction of mr. william saunders, one of our esteemed fellow workers. it was my privilege to be a good deal with mr. saunders when he was in europe studying the experience of other countries in this matter, and the policy finally adopted in canada as a result of his labors is an eminently wise one, preventing some of the difficulties and dangers which beset our plan, whether as between state and nation or college and station. under the present laws and with the vast influence which the association of agricultural colleges and experiment stations will wield, both in congress and in the different states, there is great danger of transposition, in this agricultural body politic, of those parts which in the animal body are denominated head and tail, and the old saw to the effect that "the dog wags the tail because the tail cannot wag the dog," will find another application. so far as the law goes, the national department, which should hold a truly national position toward state agricultural institutions depending on federal support, can do little except by suggestion, whether in the line of directing plans or in any way co-ordinating or controlling the work of the different stations throughout the country. the men who influenced and shaped the legislation which resulted in the hatch bill were careful that the department's function should be to indicate, not to dictate; to advise and assist, not to govern or regulate. we have, therefore, to depend on such relationships and such plans of co-operation as will appear advantageous to all concerned, and these can best be brought about through such associations as are now in convention here. without such plans there is great danger of such waste of energy and means and duplication of results as will bring the work into popular disfavor and invite disintegration, for already there is a growing feeling that agricultural experiment is and will be subordinated to the ordinary college work in the disposition of the federal appropriations. what is true of the national department as a whole in its connection with the state stations is true in a greater or less degree of the different divisions of the department in connection with the different specialists of the stations. with the multiplicity of workers in any given direction in the different states, the necessity for national work lessens. a favorite scheme of mine in the past, for instance (and one i am glad to say fully indorsed by prof. willits), was to endeavor to have a permanent agent located in every section of the country that was sufficiently distinctive in its agricultural resources and climate, or, as a yet further elaboration of the same plan, one in each of the more important agricultural states. the necessity for such state agents has been lessened, if not obviated, by the hatch bill, and the subsequent modifications looking to permanent appropriations to the state stations or colleges, which give no central power at washington. the question then arises, what function shall the national department perform? its influence and field for usefulness have been lessened rather than augmented in the lines of actual investigation in very many directions. many a state is already far better equipped both as to valuable surrounding land, laboratory and library facilities, more liberal salaries, and greater freedom from red tape, administrative routine, and restrictions as to expenditures, than we are at washington; and, except as a directing agent and a useful servant, i cannot see where the future growth of the department's influence is to be outside of those federal functions which are executive. just what that directing influence is to be is the question of the hour, not only in the broader but in the special sense. the same question, in a narrower sense, had arisen in the case of the few states which employed state entomologists. in the event, for instance, of an outbreak of some injurious insect, or in the event of any particular economic entomological question within the limits of the state having such an officer, the united states entomologist would naturally feel that any effort on his part would be unnecessary, or might even be looked upon as an interference. he would feel that there was always danger of mere duplication of observation or experiment, except where appealed to for aid or co-operation. this is, perhaps, true only of insects which are local or sectional, and is rather a narrow view of the matter, but it is one brought home from experience, and is certainly to be considered in our future plans. the favor with which the museum work of the national division was viewed by you at the meeting last november and the amount of material sent on for determination would indicate that the building up of a grand national reference collection will be most useful to the station workers. but to do this satisfactorily we need your co-operation, and i appeal to all entomologists to aid in this effort by sending duplicates of their types to washington, and thus more fully insuring against ultimate loss thereof. status of our society. this train of thought brings up the question of the status of our society with the station entomologists as represented by the committee of the general association. those of us who had desired a national association for the various purposes for which such associations are formed, felt, i believe, if i may speak for them, that the creation of the different experimental stations rendered such an organization feasible. your organization at toronto and the constitution adopted and amended at the meeting at washington all indicate that the chief object was the advancement of our chosen work and that the strength of the association would come from the experiment station entomologists. there was then no other organization of the kind, nor any intimation that such a one would be founded. some of us therefore were surprised to learn from the circular sent out by prof. forbes, its chairman, that the committee appointed by the association of agricultural colleges and experiment stations, and through which we had hoped to communicate and co-operate with that association, was not in the proper sense a committee, but a section which has prepared (and in fact was required by the executive committee and the rules of the superior body to prepare) a programme of papers and discussions for the meeting to be held at the same time and place with our own. i cannot but feel that this is in some respects a misfortune, and it will devolve upon you to decide upon several questions of importance that will materially affect our future existence. that there is not room for two national organizations having the same objects in view and meeting at the same time and place goes, i think, without saying; and if the committee of the general association is to be anything more than a committee in the proper sense of the word, or if it is to assume with or without formal constitution the functions of our own association, then our own must necessarily be crippled, and to do any good at all must meet at a different time and a different place. a committee or section, or whatever it may be called, of the general association with which we meet, would preclude active membership of any but those who come within the constitution of that body. our canadian friends and many others who have identified themselves with applied entomology, and do not belong to any of our state or government institutions, would be debarred from active representation, however liberal the association may have been in inviting such to participate, without power to vote in its deliberations. our own association has, or should have, no such limitations. some of us who are entitled to membership in both bodies may feel indifferent as to the course finally decided upon, and that it will not make any difference whether we have an outside and independent organization, as that of the association of official chemists, or whether we do, as did the botanists and horticulturists, waive independence in favor of more direct connection with the general association, provided there is some way whereby the committees of the general association are given sufficient latitude and time to properly present their papers and deliberate; but there are others who feel more sensitive as to their action and are more immediately influenced by the feelings of the main body. i hope that whatever action be taken at this meeting, the general good and the promotion of economic entomology will be kept in mind and that no sectional or personal feeling will be allowed to influence our deliberations. suggestion and comment. you will, i know, pardon me if, before concluding these remarks, i venture to make a few comments which, though not altogether agreeable, are made in all sincerity and in the hope of doing good. the question as to how far purely technical and especially descriptive and monographic work should be done by the different stations or by the national department is one which i have already alluded to and upon which we shall probably hold differing opinions, and which will be settled according to the views of the authorities at the different stations. individually, i have ever felt that one ostensibly engaged in applied entomology and paid by the state or national government to the end that he may benefit the agricultural community can be true to his trust only by largely overcoming the pleasure of entomological work having no practical bearing. i would, therefore, draw the line at descriptive work except where it is incidental to the economic work and for the purpose of giving accuracy to the popular and economic statements. this would make our work essentially biological, for all biologic investigation would be justified, not only because the life habits of any insect, once ascertained, throw light on those of species which are closely related to it, but because we can never know when a species at present harmless may subsequently prove harmful, and have to be classed among the species injurious to agriculture. on the question of credit to their original sources of results already on record, it is hardly necessary for me to advise, because good sense and the consensus of opinion will in the end justify or condemn a writer according as he prove just and conscientious in this regard. there is one principle that should guide every careful writer, viz., that in any publications whatever, where facts or opinions are put forth, it should always be made clear as to which are based upon the author's personal experience and which are compiled or stated upon the authority of others. we should have no patience with a very common tendency to set forth facts, even those relating to the most common and best known species, without the indications to which i have referred. the tendency belittles our calling and is generally misleading and confusing, especially for bibliographic work, and cannot be too strongly deprecated. on this point there will hardly be any difference of opinion, but i will allude to another question of credit upon which there prevails a good deal of loose opinion and custom. it is the habit of using illustrations of other authors without any indication of their original source. this is an equally vicious custom and one to be condemned, though i know that some have fallen into the habit, without appreciation of its evil effect. it is, in my judgment, almost as blameworthy as to use the language or the facts of another without citing the authority. every member of this association who has due appreciation of the time and labor and special knowledge required to produce a good and true illustration of the transformations and chief characteristics of an insect will appreciate this criticism. however pardonable in fugitive newspaper articles in respect of cuts which, from repeated use, have become common or which have no individuality, the habit inevitably gives a certain spurious character to more serious and official publications, for assumption of originality, whether intended or not, goes with uncredited matter whether of text or figure. nor is mere acknowledgment of loan or purchase to the publisher, institution or individual who may own the block or stone what i refer to. but that acknowledgment to the author of the figure or the work in which it first appears which is part of conscientious writing, and often a valuable index as to the reliability of the figure. it were supererogation to point out to a body of this kind the value of the most careful and thorough work in connection with life histories and habits, often involving as it does much microscopic study of structure. the officers of our institutions who control the funds, and more or less fully our conduct, are apt to be somewhat impatient and inappreciative of the time given to anatomic work, and where it is given for the purpose of describing species and of synopsizing or monographing higher groups, without reference to agriculture, i am firmly of the belief that it diverts one from economic work, but where pursued for a definite economic purpose it cannot be too careful or too thorough and i know of no instances better calculated to appeal to and modify the views of those inclined to belittle such structural study than phylloxera and icerya. on the careful comparison of the european and american specimens of _phylloxera vastatrix_, involving the most minute structures and details, depended originally those important economic questions which have resulted in legislation by many different nations and the regeneration of the affected vineyards of europe, of our own pacific coast, and of other parts of the world by the use of american resistant stocks. in the case of _icerya purchasi_ the possibilities of success in checking it by its natural enemies hung at one time upon a question of specific difference between it and the _icerya sacchari_ of signoret--a question of minute structure which the descriptions left unsettled and which could only be settled by the most careful structural study and the comparison of the types, involving a trip to europe. conclusion. i have thus touched, gentlemen, upon a few of the many subjects that crowd upon the mind for consideration on an occasion like this--a few gleanings from a field which is passing rich in promise and possibility. it is a field that some of us have cultivated for many years and yet have only scratched the surface, and if i have ventured to suggest or admonish, it is with the feeling that my own labors in this field are ere long about to end and that i may not have another occasion. at no time in the history of the world has there, i trow, been gathered together such a body of devoted and capable workers in applied entomology. it marks an era in our calling and, looking back at the progress of the past fifteen years, we may well ponder the possibilities of the next fifteen. they will be fruitful of grand results in proportion as we persistently and combinedly pursue the yet unsolved problems and are not tempted to the immediate presentation of separate facts, which are so innumerable and so easily observed that their very wealth becomes an element of weakness. epoch-making discoveries result only from this power of following up unswervingly any given problem, or any fixed ideal. the kerosene emulsion, the cyclone nozzle, the history of _phylloxera vastatrix_, of _phorodon humuli_, of _vedalia cardinalis_, are illustrations in point, and while we may not expect frequent results as striking or of as wide application as these, there is no end of important problems yet to be solved and from the solution of which we may look for similar beneficial results. applied entomology is often considered a sordid pursuit, but it only becomes so when the object is sordid. when pursued with unselfish enthusiasm born of the love of investigation and the delight in benefiting our fellow men, it is inspiring, and there are few pursuits more deservedly so, considering the vast losses to our farmers from insect injury and the pressing need that the distressed husbandman has for every aid that can be given him. our work is elevating in its sympathies for the struggles and suffering of others. our standard should be high--the pursuit of knowledge for the advancement of agriculture. no official entomologist should lower it by sordid aims. during the recent political campaign the farmer must have been sorely puzzled to know whether his interests needed protection or not. on the abstract question of tariff protection to his products we, as entomologists, may no more agree than do the politicians or than does the farmer himself. but ours is a case of protection from injurious insects, and upon that there can nowhere be division of opinion. it is our duty to see that he gets it with as little tax for the means as possible. * * * * * potash salts. [footnote: by john b. smith, entomologist. potash as an insecticide is not entirely new, but has never been brought out with the prominence i think it deserves.--_n.j. ag. col. exp. st., bulletin ._] my attention was attracted to potash salts as an insecticide, by the casual remark of an intelligent farmer, that washing his young pear trees with a muriate of potash solution cleared them of scales. the value of this substance for insecticide purposes, should its powers be sufficient, struck me at once, and i began investigation. it was unluckily too late in the season for field experiments of the nature desired; but it is the uniform testimony of farmers who have used either the muriate or the kainit in the cornfields, that they have there no trouble with grubs or cut worms. mr. e.b. voorhees, the senior chemist of the station, assures me that on his father's farm the fields were badly infested, and replanting cornhills killed by grubs or wire worms was a recognized part of the programme. since using the potash salts, however, they have had absolutely no trouble, and even their previously worst-infested fields show no further trace of injury. the same testimony comes from others, and i feel safe in recommending these salts, preferably kainit, to those who are troubled with cut worms or wire worms in corn. experiments. a lot of wire worms (_iulus_ sp.) brought in from potato hills were put into a tin can with about three inches of soil and some potato cuttings, and the soil was thoroughly moistened with kainit, one ounce to one pint of water. next morning all the specimens were dead. a check lot in another can, moistened with water only, were healthy and lived for some days afterward. a number of cabbage maggots placed on the soil impregnated with the solution died within twelve hours. to test its actual killing power, used the solution, one ounce kainit to one pint water, to spray a rose bush badly infested with plant lice. effect, all the lice dead ten hours later; the younger forms were dropping within an hour. sprayed several heads of wheat with the solution, and within three hours all the aphides infesting them were dead. some experiments on hairy caterpillars resulted unsatisfactorily, the hair serving as a perfect protection against the spray, even from the atomizer. to test its effect on the foliage, sprayed some tender shoots of rose and grape leaves, blossoms, and clusters of young fruit. no bad effect observable hours later. there was on some of the leaves a fine glaze of salt crystals, and a decided salt taste was manifest on all. muriate of potash of the same strength was tested as follows: sprayed on some greenhouse camellias badly infested by mealy bugs, it killed nearly all within three hours, and six hours later not a living insect was found. the plants were entirely uninjured by the application. thoroughly sprayed some rose bushes badly infested with aphides, and carried off some of the worst branches. on these the lice were dead next morning; but on the bushes the effect was not so satisfactory, most of the winged forms and many mature wingless specimens were unaffected, while the terminal shoots and very young leaves were drooping as though frosted. all, however, recovered later. the same experiment repeated on other, hardier roses, resulted similarly so far as the effect on the aphides was concerned, but there was no injury to the plant. used this same mixture on the caterpillars of _orgyia leucostigma_ with unsatisfactory effect, and with the same results used it on a number of other larvæ. used on the rose leaf roller, _cacæcia rosaceana_, it was promptly effective. tested for injury to plants, it injured the foliage and flowers of wisteria, the younger leaves of maple and grape, and the finer kinds of roses. from these few experiments kainit seems preferable to the muriate, as acting more effectively on insects and not injuriously on plants. for general use on plants it is not to be recommended. it is otherwise on underground species, where the soil will be penetrated by the salts and where the moisture evaporates but slowly, and the salt has a longer and better chance to act. the best method of application would be a broadcasting in fertilizing quantity before or during a rain, so as to carry the material into the soil at once. in cornfields infested with grubs or wire worms, the application should be made before planting. where it is to be used to reach root lice, it should be used when the injury is beginning. when strawberry beds are infested by the white grub, the application should be made when cultivating or before setting out. the potash salts have a high value as fertilizers, and any application made will act as a stimulant as well as insecticide, thus enabling the plants to overcome the insect injury as well as destroying the insect. in speaking on this subject in salem county, i learned from farmers present that those using potash were not troubled with the corn root louse to any extent, and also that young peach trees have been successfully grown in old lice-infested orchards, where previously all died, by first treating the soil with kainit of potash. * * * * * a meteorological station has been built on mont blanc, at an elevation of , feet, under the direction of m. vallot. it required six weeks to deliver the materials. the instruments are self-registering and are to be visited in summer every fifteen days if possible, the instruments being left to register between the visits. in the winter the observatory will be entirely inaccessible. this is the highest scientific station in europe, but is feet lower than the pike's peak station in colorado. * * * * * the expense margin in life insurance. the principle of mutuality requires that the burden of expense in life insurance should be borne by all the members equally; but, even with the most careful adjustment, the allowance usually made is considerably in excess of what is needed in the regular companies doing business on the "level premium" plan. it is customary in these companies to add to the net premium a percentage thereof to cover the expense account. this practice, though in harmony with the "commission system," is so clearly defective and so far removed from the spirit of life insurance mathematics, that it scarcely deserves even this passing notice. it is generally understood that these corporations combine the functions of the savings bank and life insurance company, and it is only by separating the two in our minds as far as possible that we can obtain a clear conception of the laws that should govern the apportionment of the expenses among the great variety of policies. while it is a comparatively simple matter to state the amount of either the insurance or savings bank element in a single policy, it is by no means easy, as things go, to classify the company's actual expenses on this basis. fortunately, we can pretty accurately determine what these amounts should be in any particular case. in the first place, there are institutions in our midst devoted solely to receiving and conserving small sums of money; doing, in fact, exactly what our insurance companies are undertaking to do with the reserve and contributions thereto. these savings banks are required by law to make returns to the state commissioner, from whose official report we can get a very good idea of the expense attendant on doing this business. confining ourselves to the city banks, where the conditions more nearly resemble those of the insurance companies, we find in thirty-eight combined institutions for saving in the state of massachusetts a deposit in of $ , , , taken care of at an aggregate cost of $ , , or about - of one per cent. the same ratio carried out for all the savings banks in massachusetts gives a trifle over - of one per cent.; we may, therefore, consider ¼ of one per cent. as expressing pretty nearly the cost of receiving, paying out, and investing the savings of the people. we must remember in this connection that in the popular estimation, the savings bank is an important factor in the public welfare, and in the towns and smaller cities there are often found public spirited men willing to give their services to encourage this mode of saving; but public sentiment has not yet given to life insurance the place which it is destined, sooner or later, to occupy by the side of the savings bank. hence the services of able managers can only be obtained by a liberal outlay of the corporate funds. a satisfactory adjustment of the matter of expenses will, perhaps, do more than anything else to bring about this recognition on the part of the public. in the case of the savings bank it is safe to say that for double the present outlay a liberal salary could be paid to all the officers. following the analogy, we are led to infer that if this be the case in savings banks, then ½ of one per cent. of the reserve should be an ample allowance for the special labor required in the purely banking portion of the business. in this we have the concurrence of the late elizur wright. in an essay on this subject he says: "the expenses of the five largest savings banks in boston, in , did not exceed - of one per cent. on $ , , deposited in them. they certainly had twice as many transactions, in proportion to the deposits, as any life insurance company could have with the same amount of reserve, so that ½ of one per cent. on the reserve seems to be ample for all working expenses save those of maintaining the agencies and collecting the premiums." this need hardly be looked upon as an admission that it costs twice as much to care for the funds of a life insurance company as for those of a savings bank. a liberal expense allowance must be made at the outset, seeing that an error in this particular cannot easily be rectified after the policy is issued. the dividend, or, to speak more correctly, the annual return of surplus, will correct any overpayment on this account. there is another expense which seems inevitable. this is the government tax on insurance companies, amounting in the aggregate to nearly / of one per cent. on the reserve. when we consider that these institutions are intended to encourage thrift and to relieve the community from the care of numberless widows and orphans, it seems a clear violation of the principles of political economy to levy a tax on this business; still, whatever our opinion may be as to the justice or injustice of the imposition, the tax is maintained and must be provided for. consequently a further allowance of ½ of one per cent. must be added to the net premium to cover the same, making a total of per cent. of the reserve for banking expenses and taxes. considering this point as settled for the time being, let us proceed to investigate the insurance expenses. here, again, we are fortunate in being able to refer to the official reports of a class of corporations doing nearly, if not quite pure insurance. the assessment societies, outside of the fraternal and benevolent, reporting in to the insurance commissioner of massachusetts, show outstanding risks amounting to $ , , . losses to the amount of $ , , were paid during the year at a cost for transacting the business of $ , , , which includes among other items "agency expenses and commissions," which amount to about $ , , , or per cent. of the cost value of the insurance actually done. it would seem as if an allowance of per cent. would be a liberal one in the case of the regular companies, which surely have as good facilities for doing business as the assessment societies. as far as insurance is concerned, there is less difference between regular and co-operative companies than is generally supposed. regular companies assess each policy in advance for a year's insurance at a time, while co-operative societies furnish insurance only from one assessment to another. the difficulty in the way of collecting the assessment in the latter case would seem to be greater than in the former, owing to the more permanent nature of the regular insurance contract. in compensating agents the assessment companies naturally pay in proportion to the insurance obtained, inasmuch as there is no other basis to go upon, but regular companies usually pay the agent a percentage of the premium _which includes a considerable trust fund_ over and above the assessment for actual insurance. it is easily seen that by the last method the agent's compensation increases in proportion to the amount of savings bank business forced upon the company. to realize how far we are from anything like a scientific, not to say common sense basis for insurance expenses, we have but to examine the following list, which gives the ratios between the expenditures for general expenses in , and those for the extension of the business. for every $ used in a general way, the different companies spend for commissions and agency expenses: $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ , $ . it will doubtless be said that i am taking a very advanced position when i say that in the ideal life insurance scheme there is no place for the commission system. solicitors will be a necessity only so long as they are in the field, but fifty years of life insurance has taught our community its true value and, thanks to the modern press, the institution it is no more likely to fall into desuetude than is christianity or the moral law. for the convenience of bringing the company to the individual, the latter should be willing to pay a fee. the man who renders another a service or puts his superior knowledge at another's disposal should look to the party benefited for his remuneration. any compensation given for such service to a go-between by a mutual company is paid by all, and the question arises, is the advantage to the company of sufficient importance to warrant the imposition of this tax upon all its members promiscuously? the following, from the massachusetts insurance commissioner's report for , leaves no doubt as to the convictions of the writer on this important matter: "the expensiveness of the life insurance policy is not because the level net premium is too high, for the premium is absolutely just, and the policy holder gets full value; but the complaint justly applies to the excessive expense charge. a person who wants insurance, life or fire or other, should be able to buy it at first cost without paying tribute of profits to middlemen. to that complexion the matter will finally be brought by the force of intelligent opinion, whatever resistance may be opposed by persons whose thrift lies in the perpetuation of the expensive system now in fashion." it requires but a slight degree of prophetic vision to predict that in a very few years the companies in self defense will be obliged to change their method of compensating agents. several companies have already begun the reform by grading commissions; granting a percentage proportional to the amount of insurance likely to be done on the policy. other companies have simply reduced the amount of the commission rate, thus virtually withdrawing from active competition. this will, in a certain degree, explain the wide variation in the figures given above, where it is noticed that, in five companies out of twenty-two, the total agency expenditures amount to less than the general expenses, while in six cases the companies spend more than double as much on the former as on the latter. in either class we find representatives of the five largest companies in the country. on applying the foregoing ratios to the business of the existing companies we find that, calling the theoretical expenses $ , the actual expenditures for were as follows: $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . . in this discouraging exhibit there is one ray of comfort. the combined assets of the two companies heading the list amount to over $ , , . there is no question as to their financial standing, and both show a large increase in membership over the previous year. i may also say here that it is a difficult matter to get at the actual "cost of insurance" in the various companies. many of them, on their own acknowledgment, do not compute the advance cost of carrying their "amount at risk," and others, for reasons of their own, do not care to state the figures. in cases where the correct figures were not obtainable, i have assumed the cost to have been - / per cent. of the mean amount at risk. if we should, in our comparison, omit the actual agency expenses and commissions, the ratios would stand as follows: where i would allow $ the companies actually used: $ . , $ . , $ . , $ . , $ . , $ . , $ . . $ . . $ . , $ . , $ . . $ . . $ . . $ . , $ . , $ . , $ . , $ . , $ . , $ . , $ . . as might be supposed, the first two ratios are those companies before alluded to. these companies might have doubled their advertising account and expended $ , between them on agents' salaries, and still have kept within my allowance. admitting, for the present at least, the reasonableness of the proposed allowance for the expenses of the banking and insurance departments of the business, we have before us the problem how to equitably adjust the burden among the great variety of policies. in the first place, _there should be no policy in the company that does not contribute its proportionate share of the expense allowance during every year of its life_. i make a special point of this, for at present the policies which have become paid up, either by the payment of a single premium at the outset or by the completion of a stipulated number of payments, contribute practically nothing to the expense account after the premium payments cease. the following plan, i think, complies with all the requirements of the problem. by the proposed method every policy, at all stages of its existence, contributes its exact share to the expense fund, whatever its plan of payment may be. let us, as an illustration, examine the case of a ten year endowment policy, taken out at age , and consider it under three aspects, first, as paid for in advance by a single payment, second, as paid by five annual payments, and third, as paid for annually throughout the term. i have used this short term endowment policy simply for convenience, the rule applying equally to policies of longer term or to the ordinary life policy, which is, in fact, an endowment policy payable at death or age .[ ] [footnote : the expense allowance on a plain life policy for $ , , taken at age , would be about $ . ; net premium (com. ex. per cent.), $ . ; total office premium, $ . ; present rate $ . .] taking the case of the single premium endowment policy for $ , , we find that the following sums are required, each year to provide for the care of the reserve and to pay the government fees ( per cent. of reserve): st year $ . | th year $ . d " . | th " . d " . | th " . th " . | th " . th " . | th " . the insurance expenses should be covered by the per cent. allowance given below: st year $ . | th year $ . d " . | th " . d " . | th " . th " . | th " . th " . | th " . consequently the total contribution required from this policy each year is: st year $ . | th year $ . d " . | th " . d " . | th " . th " . | th " . th " . | th " . the present value of all these contributions is found to be, at per cent. interest, $ . ; in other words, this sum paid at the outset, provides a fund from which we may deduct the current expenses of each year in advance, and by accumulating the balance at the assumed rate of interest from year to year, we shall have enough to pay the anticipated expenses, leaving nothing over. in the above case the sums in hand at the beginning of the year are as follows: st year $ . | th year $ . d " . | th " . d " . | th " . th " . | th " . th " . | th " . we find a somewhat different condition existing during the first years of a -year endowment policy. as there is more insurance and less banking, the requirements are as follows: ------------+----------+-----------+--------+---------+ | p. ct. | p. ct. | | | | on | on | total. | initial | | reserve. | cost. | | fund. | ------------+----------+-----------+--------+---------+ st year | $ . | $ . |$ . |$ . | d " | . | . | . | . | d " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | ------------+----------+-----------+--------+---------+ as the premium payments extend over only five years, the expense contributions must all be paid during that time and are most conveniently made by a uniform addition to the net premium. the present value of the amounts in column is $ . , and the equivalent annuity for five years is $ . . this amount, received for five consecutive years, will put the company in funds to pay current expenses and leave a reserve of $ . at the beginning of the sixth year, which, as we have seen in the analysis of the single-premium policy, is the sum required for future expenses on the paid up basis. in like manner we find that the -year annuity equivalent to the present value of the annual contributions in the case of an annual-payment policy is $ . , thus: ------------+----------+-----------+--------+---------+ | p. ct. | p. ct. | | | | on | on | total. | initial | | reserve. | cost. | | fund. | ------------+----------+-----------+--------+---------+ st year | $. | $ . |$ . |$ . | d " | . | . | . | . | d " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | th " | . | . | . | . | ------------+----------+-----------+--------+---------+ the present value of the ten yearly expense items given in the "total" column above is $ . , which is equal to a ten-year annuity of $ . . the several premiums stand now as follows: endowment: $ , , age , payable at death or net prem.[ ] margin. total. at single premium. $ . $ . $ . at five premiums. . . . at annual premiums. . . . [footnote : thirty american offices. discount from middle of year, vx-½ or (m x . ) / dx.] by the actuaries' rate we have, with the customary loading for expense: single premium: $ . (loaded, $ . ). five premiums, $ . (loaded $ . ). annual premium, $ . (loaded $ . ). admitting the correctness of the new method, we must conclude that the present single premium is not sufficiently loaded to cover its own expenses, while the annual payment policy pays more than its just share. a prominent and thoroughly informed life insurance president says in this connection: "many of the policies, particularly the short term endowments, are charged with too high a percentage of expenses to prove a good investment at maturity or profitable to the insured in case of surrender." this is not to be wondered at when the applicant for a -year endowment policy sees at a glance that he must pay, in the gross, more than is returned unless he should die in the interim, in which case a plain "life" or "term" policy would have answered the purpose. under the new system of assessing expenses one form is as desirable as another, from the standpoint of the insured or the company. the new premium for the -year endowment policy, $ . , commends itself at once to the applicant, who can easily see that his total outlay must fall short of the amount ultimately to be realized, of course, disregarding interest and probable dividends in both cases. in discounting the future expense contributions i have not taken the chances of dying into account. hence the expense reserve in any instance applies only to that individual case, and, in the event of death or surrender before the maturity of the policy, the amount of the expense fund not used would naturally revert to the insured. the scheme of expense assessment outlined above will doubtless be pronounced impracticable by the majority of insurance men. such a far reaching reform is too much to hope for, at least in the immediate future. no well informed life insurance expert will deny that there are opportunities for improvement in the business, but to graft new methods on old companies is a hopeless undertaking. it is well, however, to have new methods well matured in advance of the public demand, and i feel convinced that the ideas here set forth are in the line of the reform which, before long, must be instituted by the companies if they would retain the confidence and patronage of the community. doubtless many insurance presidents could tell of suggestions which have impressed them favorably and which they would gladly have adopted were it not for the injustice done thereby to older members and the changes necessary to bring existing contracts into conformity with the new system. similar objections may be urged against the ideas here advanced, and i must confess i hardly see a way by which the present suggestions can be utilized by existing companies. we can only hope that sooner or later some of the new theories may be practically tested. meanwhile the companies at present in the field are doing a great work for the good of humanity, even though their methods may be, in some particulars, more practical than scientific. winchester, mass. frank j. wills. * * * * * the flood at karlsbad. during the flood which occurred in germany and bohemia, the last week of november, karlsbad was especially unfortunate; it suffered such an inundation as had never before been known in the "sprudelstadt." on the evening of november , the tepl was very much swollen by the rain, which had continued for several days, but it was supposed that there was no danger of a flood, as the bed of the river had been put in proper condition. during the forenoon of november , the water suddenly began to rise with such astonishing rapidity that within half an hour all the lower streets were like turbulent rivers and the alte and neue wiese were transformed into a lake. the stores on the alte wiese were under water to the roofs, and the proprietors, who were trying to save their goods, were surprised by the water and had to take refuge in the trees. they were rescued by having ropes thrown to them, and during this work a catastrophe occurred which was a great misfortune to all classes of citizens. the beloved burgermeister of karlsbad, dr. rudolf knoll, who had just recovered from a severe illness, was, with others, directing the work from the balcony of one of the houses, when a rope by which a man was being drawn through the water broke, and the man was carried off by the waves. the fright and excitement of the scene gave the burgermeister a shock which caused his instant death, but the man who was in danger was brought safely out of the water. the water was ft. in marienbaderstrasse, the marktplatz, muhlbadgasse, the sprudelgasse, kreuzgasse, kaiserstrasse, and egerstrasse, and flooded the quay, causing great destruction. all places of business were flooded, the doors and iron shutters were pushed in by the force of the water and the goods were carried away or ruined. the house called "zum kaffeebaum" was undermined and part of it fell to the ground; the same fate was feared for other buildings. the sophien and curhaus bridges were carried away. other bridges were greatly damaged, and the masonry along the banks of the river was partially destroyed. the sprudelgasse was completely washed out, and the condition of the muhlbadgasse was almost as bad. the fire department with its apparatus had great difficulty in saving the inhabitants and guests, as there were very few boats or pontoons at their command, and the soldiers (pionniere) from prague and the firemen from the neighboring towns did not arrive until evening. fortunately the water began to fall in the night, and the next day it had gone down so that it left its terrible work visible. the sprudel and the mineral springs were not injured, but, on the other hand, the water pipes of the bathing establishments and the gas pipes were completely destroyed.--_illustrirte zeitung._ * * * * * theatrical water plays. in one of the plays at hengler's circus in london a water scene is introduced, for which purpose the main ring is flooded with water in a manner which is both striking and interesting. [illustration: flooding a circus ring.] the ring is entirely lined with stout macintosh sheeting, and into this, from two large conduits. , gallons of water are poured, the tank being filled to a depth of some ft. in the remarkably short time of seconds. a steamboat and other small craft are then launched and the adventures of the heroine then proceed. she falls overboard, we believe, but is saved after desperate and amusing struggles. our engravings, which are from the _graphic_, illustrate the mode of filling the ring with water, and the steamboat launch. [illustration: a theatrical steamboat.] * * * * * science in the theater. in the pretty little hall of the boulevard des italiens, at paris, a striking exhibition of simulated hypnotism is given every evening. this entertainment, which has met with much success, was devised by mr. melies, director of the establishment, which was founded many years ago by the celebrated prestidigitator whose popular name (robert houdin) it still bears. this performance carries instruction with it, for it shows how easily the most surprising phenomena of the pathologic state can be imitated. to this effect, several exhibitions are given every evening. mr. harmington, a convinced disciple of mesmer, asks for a subject, and finds one in the hall. a young artist named marius presents himself. mr. harmington makes him perform all sorts of extravagant acts, accompanied with a continuous round of pantomimes that are rendered the more striking by the supposed state of somnipathy of the subject. at the moment at which marius is finishing his most extraordinary exercises, a policeman suddenly breaks in upon the stage in order to execute the recent orders relative to hypnotism. but he himself is subjugated by mr. harmington and thrown down by the vibrations of which the encephalus of this terrible magnetizer is the center. when the curtain falls, the representative of authority is struggling against the catalepsy that is overcoming him. all the phenomena of induced sleep are successively simulated with much naturalness by mr. jules david, who plays the part of marius in this pleasing little performance. at a certain moment, after skillfully simulated passes made by the magnetizer, mr. david suddenly becomes as rigid as a stick of wood, and falls in pivoting on his heels (fig. ). did not mr. harmington run to his assistance, he would inevitably crack his skull upon the floor, but the magnetizer stands just behind him in order to receive him in his arms. then he lifts him, and places him upon two chairs just as he would do with a simple board. he places the head of the subject upon the seat of one of the chairs and the heels upon that of the other. mr. david then remains in a state of perfect immobility. not a muscle is seen to relax, and not a motion betrays the persistence of life in him. the simulation is perfect. [illustration: fig. .--cataleptic rigidity.] in order to complete the astonishment of the spectators, mr. harmington seats himself triumphantly upon the abdomen of the subject and slowly raises his feet and holds them suspended in the air to show that it is the subject only that supports him, without the need of any other point of support than the two chairs (fig. ). [illustration: fig. .--experiment on the same subject.] usually, there are plenty of persons ingenuous enough to think that mr. david is actually in a cataleptic sleep, one of the characters of which is cadaveric rigidity. as mr. david's neck is entirely bare, it is not possible to suppose that the simulator of catalepsy wears an iron corset concealed beneath his clothing. he has performed a feat of strength and skill rendered easy by the exercise that he has given to the muscles occupying the _colliciæ_ of his vertebral column. this part of the muscular system is greatly developed in the weakest and least hardy persons. in fact, in order that man may keep a vertical position and execute an infinite multitude of motions in which stability is involved, nature has had to give him a large number of different organs. the muscles of the back are arranged upon several superposed layers, the vertebral column is doubly recurved in order that it may have more strength, and, finally, rachidion nerves issue from each vertebra in order to regulate the contraction of each muscular fasciculus according to the requirements of equilibrium. the trick is so easy that we have seen youths belonging to the ligue d'education physique immediately imitate mr. david after seeing him operate but once. for the sake of those who would like to perform it, we shall add that mr. david takes care to bend his body in the form of an arch in such a way that the convexity shall be beneath. as mr. harmington never fails to place himself in the center of the line that joins mr. david's head and heels, his weight is divided into two parts, that is to say, pounds on each side of the point of support. the result is that the stress necessary is less than that of a strong man of the halle lifting a bag of wheat to his shoulder or of an athlete supporting a human pyramid. the force of contraction of the muscular fibers brought into play in this experiment is much greater than is commonly believed. in his lectures on physiology, milne-edwards cites some facts that prove that it may exceed pounds per square inch of section. [illustration: fig. .--the perforate arm.] the experiment on cadaveric rigidity is followed by others in insensibility. mr. david, without wincing, allows a poignard to be thrust into his arm, which mr. harmington has previously "cataleptized" (fig. ). this trick is performed by means of a blade divided into two parts that are connected by a semicircle. this process is well known to prestidigitators, but it might be executed in a genuine manner. in fact, on replacing the poignard by one of the gold needles used by physicians for acupuncture, it would be possible to dispense with prestidigitation. under such conditions it is possible to transpierce a person's arm. the pain is supportable, and consists in the sensation of a prick produced in the passage of the needle through the skin. as for the muscular flesh, that is of itself perfectly insensible. the needle, upon the necessary antiseptic precautions being taken, may traverse the veins and arteries with impunity, provided that it is not allowed to remain long enough to bring about the formation of a clot of coagulated blood (fig. ). [illustration: fig. .--an arm transpierced by a needle.] we think it of interest to add that it is necessary that the experiment be performed by a practitioner if one desires to demonstrate upon himself a very curious physiological fact that has been known from the remotest antiquity. it has been employed for several thousand years in chinese medicine, for opening a passage for the bad spirits that produce diseases. for some years past a much more serious use has been made of it in european medicine for introducing electric currents into the interior of the organism. in this case the perimeter of the needle is insulated, and the electricity flows into the organism through the point. we have several times had these operations performed upon ourselves, and this permits us to assert that the above mentioned facts are absolutely true.--_la nature._ * * * * * newer physiology and pathology. by prof. samuel bell, m.d. physiology has for many decades been a science founded on experiment, and pathology has been rapidly pressing forward in the same direction. to read the accounts of how certain conclusions have been arrived at in the laboratory, by ingenious devices and by skillful manipulations, is as fascinating as any tale of adventure. when the microscope began its work, how discouraging was the vastness and complexity of the discoveries which it brought to light; how many years has it been diligently used, and how uncertain are we still about many of its revelations! but what a happy conjecture of man, and as proper environment takes place we may reach better results! let me give an illustration: some thirty years ago, virchow began his studies and lectures upon cellular pathology. the enthusiasm which he awakened spread over the whole medical world. the wonderful attention to detail, the broad philosophy which signalized his observations, were alike remarkable. his class room was packed with students from every country, who thought it no hardship to struggle for a seat at eight o'clock in the morning. with his blackboard behind him and specimens of pathology before him, and microscopes coursing upon railway tracks around the tables which filled the room, he was the embodiment of the teacher; his highest honor was as discoverer. the life and importance of the cell, both in health and disease, it has been his work to discover and to teach. the point of view from which he has classified tumors is founded on this basis, and remains the accepted method. the light which he cast upon the nature of inflammation has not yet been obscured, and while other phenomena appear, the multiplication of cells and nuclei and the formation of connective tissue in the process of inflammation will always call to mind his labors. to one of virchow's pupils, prof. recklinghausen, we chiefly owe our knowledge of the phenomena of diapedesis as a part of the inflammatory activity. how incredible it seems that masses of living matter can make their way through the walls of blood vessels which do not rupture and which have no visible apertures! virchow fixed his attention upon the forms and activities of the cells, their multiplication and degradation, and how they build up tissues, both healthy and morbid. to another matter with which, both literally and metaphorically, the air is filled, we must also make allusion. the existence of micro-organisms in countless numbers is no new fact, but the influence they may exert over living tissues has only lately become the subject of earnest attention. so long as they were not known to have any practical bearing upon human welfare, they interested almost nobody, but when, however, it was shown that putrefaction of meat is due to the agency of the _bacterium termo_, and the decomposition of albumen to the _bacillus subtilis_; when anthrax in cattle and sheep was found to depend on the _bacillus anthracis_, and that in human beings it caused malignant pustules; when suppuration of wounds was found to be associated with micrococci; and when it was announced that by a process of inoculation cattle could be protected against anthrax, and that by carbolic spray and other well known precautions the suppuration of wounds could be prevented--all the world lent its ears and investigation at once began. because labors in bacteriology promised to be fruitful in practical results, the workers speedily became innumerable, and we are accumulating a wondrous store of facts. how long now is the list of diseases in which germs make their appearance--in pneumonia, in endocarditis, in erysipelas, in pyæmia, in tuberculosis, and so on and so on. one of the most striking illustrations is the gonococcus of gonorrhoea, whose presence in and around gives to the pus cells their virulent properties, and when transferred to the eye works such lamentable mischief. without their existence the inoculation of pus in the healthy eye is harmless; pus bearing the gonococci excites the most intense inflammation. similar suppurative action in the cornea is often caused by infection of cocci. the proof of causation may be found in the fact that the most effective cure now practiced for such suppuration is to sterilize them by the actual cautery. rosenbach says that he knows six distinct microbes which are capable of exciting suppuration in man. their activity may be productive of a poison, or putrefactive alkaloid, which is absorbed. there are at present two prominent theories in regard to the infections which produce disease. the first is based upon chemical processes, the second upon the multiplication of living organisms. the chemical theory maintains that after the infectious element has been received into the body it acts as a ferment, and gives rise to certain morbid processes, upon the principle of catalysis. the theory of organisms, or the germ theory, maintains that the infectious elements are living organisms, which, being received into the system, are reproduced indefinitely, and excite morbid processes which are characteristic of certain types of disease. this latter theory so readily explains many of the facts connected with the development and reproduction of infectious diseases, that it has been unqualifiedly adopted by a large number of investigators. the proofs of this theory had not, however, advanced beyond the demonstrations of the presence of certain forms of bacteria in the pathological changes of a very limited number of infectious diseases, until february, , when koch announced his discovery of the tubercle bacillus, since which time nearly every disease has its supposed microbe, and the race is, indeed, swift in which the would-be discoverers press forward with new germs for public favor. the term bacteria or microbe refers to particles of matter, microscopic in size, which belong to the vegetable kingdom, where they are known as fungi. if we examine a drop of stagnant water under the microscope, amplifying say four hundred diameters, we see it loaded with minute bodies, some mere points, others slightly elongated into rods, all actively in motion and in various positions, a countless confusion. if evaporation now takes place, all is still. if we now apply moisture, the dried-up granules will show activity, as though they had not been disturbed. all these different organisms have become familiar to us under the generic term bacteria, which is a very unfortunate application, as it really applies to only a single class of fungi. cohn calls them schizomycetes, and makes the following classifications: . _sphero-bacteria_, or microbes. . _micro-bacteria_, or bacteria. . _desmo-bacteria_, or bacilli. . _spiroteria_, or spirillæ. the _spiro-bacteria_, or micrococci, are the simplest of the fungi, and appear as minute organisms of spherical form. they multiply by fission, a single coccus forming two, these two producing four, and so on. they present a variety of appearances under the microscope. from single isolated specimens (which under the highest magnifying power present nothing beyond minute points) you will observe them in pairs, again in fours, or in clusters of hundreds (forming zoöglea) and still adhering together, forming chains. when a given specimen is about to divide, it is seen to elongate slightly, then a constriction is formed, which deepens until complete fission ensues. micrococci possess no visible structure. they consist of a minute droplet of protoplasm (mycroprotein) surrounded by a delicate cell membrane. certain forms are embedded in a capsule (diameter . to . millimeter). these little organisms, when observed in a fluid like blood, sputum, etc., are found to present very active movements, although provided with no organs of locomotion. this brownian motion is possessed by almost every minute particle of matter, organic and inorganic, and is not due to any inherent power of the individual. they are almost omnipresent, abounding in the air, the earth, the water, are always found in millions where moist organic matter is undergoing decomposition, and are associated with the processes of fermentation--in fact, they are essential to it. the souring of milk succeeds the multiplication of these germs. certain varieties are pigmented, and we observe colonies of chromogenic cocci multiplying upon slices of boiled potato, eggs, etc., presenting all the colors of the rainbow. all of these germs are not the cause of disease. certain species, however (termed pathogenic), are always associated with certain diseased conditions. the _bacteria-termo_--micro-bacteria--are slightly elongated, and inasmuch as they multiply by division, frequently appear coupled together, linked in pairs, and in chains. they are generally found in putrefying liquids, especially infusions of vegetable matter. they possess mobility to a remarkable degree. observing a field of bacteria-termo under the microscope, they may be seen actively engaged in twining and twisting. a flagellum has been demonstrated as attached to one or both extremities. this is too minute to be generally resolved, even if it is a common appendage. _desmo-bacteria_ (or bacilli) are rod-like organisms, occurring of various lengths and different thicknesses. in a slide of the bacillus of tuberculosis and anthrax, we notice at intervals dots which represent the spores from which, as the rods break up, future bacilli are developed. then we have _spiro-bacteria,_ the spirilla and the spirochetæ; the former having short open spirals, the latter long and closely wound spirals. the _spirillum, volutans_ is often found in drinking water, and in common with some other specimens of this class is provided with flagellæ, sometimes at both extremities, which furnish the means of rapid locomotion. the spiro-bacteria multiply by spores, although little is at present known of their life history. they frequently are attached together at their extremities, forming zigzag chains. we have seen that bacteria differ greatly in appearance from the elongated dot of the bacterium proper, to the elongated rod or cylinder of the bacillus, and the long spirals of spiro-bacteria. it is unfortunate that they are not sufficiently constant in habit to always attach themselves to one or the other of these genera. the micrococcus has a habit of elongating at times until it is impossible to recognize him except as a bacterium; while bacilli, again, break up until their particles exactly resemble micrococci. bacteria cannot exist without water; certain forms require oxygen, while others thrive equally well without it; some thrive in solution of simple salts, while others require albuminoid material. bacteriology, with its relation to the science of medicine, is of importance to every investigating physician; it covers our knowledge of the relation of these minute organisms to the ætiology of disease. what has been gained as to practical application in the treatment of disease? this question is not infrequently asked in a sneering manner. we can, in reply, say that the results are not all in the future. it is encouraging that results have been attained which have had a very important practical bearing, and that these complaints come generally from individuals least acquainted with scientific investigations in bacteriology. in the study of the relation of a given bacterium to a certain disease, it becomes necessary to attend carefully to three different operations: first, the organism supposed to cause the disease must be found and isolated. second, it must be cultivated through several generations in order that absolute purity may be secured. lastly, the germ must be again introduced into a healthy living being. if the preceding steps be carried out, and the original disease be communicated by inoculation, and the germs be again found in the diseased body, we have no alternative; we must conclude that we have ascertained the cause of the disease. the importance of being familiar with the ætiology of the disease before we can expect to combat it with any well-grounded hope of success is evident. if the sputum of a phthisical patient be submitted to the skilled microscopist, he is nearly always able to demonstrate bacilli, but this goes for very little. because bacilli are found in phthisis, it is no more certain that they are the cause of phthisis than it is certain that cheese mites are the cause of cheese. well, suppose we were to inject sputum from a phthisical person into the lower animal and tuberculosis follows, and then announce to the profession that we have demonstrated the relation of the cause and effect between bacilli and phthisis? why we would start such an uproar of objections as would speedily convince us that there was much work yet in the domain of bacteriology. the scientific investigators would say you have injected with the sputum into the blood of your unfortunate patient, pus, morphological elements, and perhaps half a dozen other forms of bacteria, any one of which is just as likely to produce the disease as the bacillus you have selected. the first important step is, first isolate your bacillus. if i were to take a glass plate, one side of which is coated with a thick solution of peptonized gelatin, and allow the water to collect, the gelatinous matter will become solid. if now, with a wire dipped in some tuberculous matter, i draw a line along the gelatin, i have deposited at intervals along this line, specimens of tubercle bacilli. if this plate be now kept at a proper temperature, after a few days, wherever the bacilli have been caught, a grayish spot will appear, which, easily seen with the naked eye, gradually spreads and becomes larger. these spots are colonies containing thousands of bacilli. let us return to our gelatin plate. we find a spot which answers to the description of a colony of tubercle bacilli. we now take a minute particle from this colony on a wire and convey it to the surface of some hardened blood serum in a test tube. we plug the tube so that no air germs may drop in, and place it in an incubator at the proper temperature. after several days, if no contamination be present, a colony of bacilli will appear around the spot where we sowed the spores. let us repeat the process. take a particle from this colony, and transfer it to another tube. this is our second culture. this must be repeated until we are satisfied that we have secured a _pure_ culture. if this be carried to the twenty-fifth generation, we may be assured that there remains no pus, no ptomaines, nothing but the desired bacilli. it is a proper material now for inoculation, and if we inoculate some of the lower animals, for instance the monkey, we produce a disease identical with phthisis pulmpnalis. bacteria also afford peculiar chemical reactions. for example, nitric acid will discharge all the color from all bacilli artificially dyed with anilin, except those of tubercle and anthrax. one species is stained readily with a dye that leaves another unaltered. thus we are enabled in the laboratory to determine whether the bacilli found in sputum, for example, are from tubercle or are the bacteria of decomposition. from what i have said of the tubercle bacillus, it would seem thoroughly demonstrated that it is the cause of tubercle in these animals. but we must walk cautiously here. these are not human beings, who know that like results would follow their inoculation. the animals used by koch are animals very subject to tubercle. we must, from the very nature of our environment, be constantly inhaling these germs as we pass through the wards of our hospitals; yes, they are floating in the air of our streets and dwellings. it becomes necessary then for us to inquire: if bacteria cause disease, in what manner do they produce it? the healthy organism is always beset with a multitude of non-pathogenic bacteria. they occupy the natural cavities, especially the alimentary canal. they feed on the substances lying in their neighborhood, whether brought into the body or secreted by the tissues. in so doing they set up chemical changes in their substances. where the organs are acting normally these fungi work no mischief. the products of decomposition thus set up are harmless, or are conveyed out of the body before they begin to be active. if bacteria develop to an inordinate degree, if the contents of organs are not frequently discharged, fermentative processes may be set up, which result in disease. bacteria must always multiply and exist at the expense of the body which they infest, and the more weakened the vital forces become, the more favorable is the soil for their development. septicæmia is caused by the absorption of the products of putrefaction, induced before bacteria can multiply inside or outside the body. bacteria must find a congenial soil. the so-called cholera bacillus must gain access to the intestinal tract before it finds conditions suitable to colonization. it does not seem to multiply in the stomach or in the blood, but once injected into the duodenum develops with astonishing rapidity, and the delicate epithelial cells of the villi become swollen, soften and break down, exposing the mucosa. it has been shown that _bouillon_ in which loeffler's diphtheria bacillus has grown, and which has been passed through unglazed porcelain filters, shows the presence of a poison which is capable of producing the same results upon inoculation as the pure culture of the bacillus itself. zarniko, working upon the same organism, obtained a number of positive results that led him to declare this bacillus is the cause of epidemic diphtheria, in spite of many assertions to the contrary. chantmesse and widal record the results of their work as to what will most easily and effectively destroy the bacillus of diphtheria. the only three substances that actually checked and destroyed its vitality were phenic acid ( per cent.), camphor ( per cent.), olive oil ( per cent.), in combination. for the last i substitute glycerine, because this allows the mixture to penetrate farther into the mucous membrane than oil, the latter favoring a tendency to pass over the surface. this mixture when heated separates into two layers, the upper one viscid and forming a sort of "glycerol," the lower clear. the latter will completely sterilize a thread dipped in a pure culture of the diphtheria bacillus. corrosive sublimate was not examined because in strong enough doses it would be dangerous and in weaker ones it would be useless. the facts obtained in regards to the streptococcus of erysipelas are reported as follows: that both chemical and experimental evidence teach the extreme ease of a renewed attack of the disease; that it is possible to kill guinea pigs by an intoxication when they are immune to an inoculation of the culture in ordinary quantities. and this latter fact should warn experimenters trying to obtain immunity in man by the inoculation of non-pathogenic bacteria, because the same results may be reached. a new theory in regard to fevers and the relation of micro-organisms is suggested by roussy, viz.: that it is a fermentation produced by a diastase or soluble ferment found in all micro-organisms and cells, and which they use in attacking and transforming matter, either inside their substance or without it. the resemblance of the malaria parasite to that of recurrent fever is noted in the work of sacharoff. he states that there exists in the blood of those suffering from recurrent fever a hæmatozoon, which is most prominent after the fever has begun to fall, when it is of enormous proportions, twenty or more diameters of a red blood corpuscle, although smaller ones may still be found. the parasite consists of a delicate amoeboid body containing a multitude of dark, round, uniform, sharply outlined, movable granules. besides these, the protoplasm contains a generally grayish homogeneous nucleus as large as one or two red blood corpuscles. the protoplasm sends out pseudopodia (with granules), which sometimes separate and appear as small delicate pieces of protoplasm. they vary in size, and are often swallowed by the red blood corpuscles in which they grow, and finally develop into the above mentioned amoeboid bodies. prof. j. lewis smith has made a great many autopsies of children dead from cholera infantum, and almost invariably found the stomach and liver in a comparatively healthy condition. ganghen, who has given this subject considerable study, denies the existence of any specific germ in the summer diarrhea of infants, but claims to have found three different germs in the intestines of children suffering from cholera infantum, each producing a chemical poison which is capable of producing vomiting, purging, and even death. a great variety of germs are found in drinking water, and no doubt countless numbers are taken into the digestive tract, and the principal reason why pathological conditions do not occur more frequently is on account of the germicidal qualities of the gastric juice. the comma bacillus of koch, and the typhoid fever germ of eberth, are especially destroyed in normal gastric juice. when the germs are very numerous, they run the gauntlet of the stomach (as the gastric juice is secreted only during digestion); and once in the alkaline intestinal canal they are capable of setting up disease, other conditions contributing--ill health, deranged digestion, etc. mittnam has made a study of bacteria beneath the nails, and reports, after examining persons following different occupations, having found numerous varieties of micro-organisms; which are interesting from a scientific standpoint relative to the importance of thoroughly cleansing the hands before undertaking any surgical procedure. he found, out of twenty-five experiments, varieties of bacteria, of which were classed as micrococci, diplococci, rods, sarcinæ, and yeast. cooks, barbers, waiters, etc., were examined. the blood, defibrinated and freshly drawn, has marked germicidal action; for bacteria its action is decidedly deadly, even hours after it has been drawn from the body. especially were anti-germic qualities noticed upon pathogenic bacteria. buchner put the bacilli of anthrax in a quantity of blood, and in two hours the number was reduced from , to , and in three hours only living bacteria remained. other bacteria were experimented upon in blood with similar results, but the destruction of the organism from putrefaction was much less marked, and on some varieties the blood had little or no action. it is not the object of these remarks to even give a _résumé_ of the _status præsens_ of bacteriology, but simply to stimulate thought in that direction. the claims of some of the ultra-bacteriologists may never be realized, but enough has been accomplished to revolutionize the treatment of certain diseases, and the observing student will do well to keep his eye on the microbe, as it seems from the latest investigations that its star is in the ascendant. and who can prognosticate but that in the next decade an entire revolution in the ætiology and treatment of many diseases may take place? detroit, mich. * * * * * the composition of koch's lymph. what professor koch says it is, and what it can do. (by cable to the _medical record_.) berlin, january , . the curiosity to know the composition of the famous lymph has been gratified by the publication to-day of an article by professor koch on the subject. in the following, as will be seen, he reaffirms his original convictions and acknowledges the valuable assistance he has received from those who have used his fluid, and thus helped him in the accumulation of experience. professor koch says: two months ago i published the results of my experiments with the new remedy for tuberculosis, since which time many physicians who received the preparation have been enabled to become acquainted with its properties through their own experiments. so far as i have been able to review the statements published and the communications received by letter, my predictions have been fully and completely confirmed. the general consensus of opinion is that the remedy has a specific action upon tubercular tissues, and is, therefore, applicable as a very delicate and sure reagent for discovering latent and diagnosing doubtful tuberculous processes. regarding the curative effects of the remedy, most reports agree that, despite the comparatively short duration of its application, many patients have shown more or less pronounced improvement. it has been affirmed that in not a few cases even a cure has been established. standing quite by itself is the assertion that the remedy may not only be dangerous in cases which have advanced too far--a fact which may forthwith be conceded--but also that it actually promotes the tuberculous process, being therefore injurious. during the past six weeks i myself have had opportunity to bring together further experiences touching the curative effects and diagnostic application of the remedy in the cases of about one hundred and fifty sufferers from tuberculosis of the most varied types in this city and in the moabit hospital. i can only say that everything i have latterly seen accords with my previous observations. there has been nothing to modify in what i before reported. as long as it was only a question of proving the accuracy of my indications, it was needless for any one to know what the remedy contained or whence it was derived. on the contrary, subsequent testing would necessarily be more unbiased, the less people knew of the remedy itself. now, after sufficient confirmatory testing, the importance of the remedy is proved, my next task is to extend my study of the remedy beyond the field where it has hitherto been applied, and if possible to apply the principle underlying the discovery to other diseases. this task naturally demands a full knowledge of the remedy. i therefore consider that the time has arrived when the requisite indications in this direction shall be made. this is done in what follows. before going into the remedy itself, i deem it necessary for the better understanding of its mode of operation to state briefly the way by which i arrived at the discovery. if a healthy guinea pig be inoculated with the pure cultivation of german kultur of tubercle bacilli, the wound caused by the inoculation mostly closes over with a sticky matter, and appears in its early days to heal. only after ten to fourteen days a hard nodule presents itself, which, soon breaking, forms an ulcerating sore, which continues until the animal dies. quite a different condition of things occurs when a guinea pig already suffering from tuberculosis is inoculated. an animal successfully inoculated from four to six weeks before is best adapted for this purpose. in such an animal the small indentation assumes the same sticky covering at the beginning, but no nodules form. on the contrary, on the day following, or the second day after the inoculation, the place where the lymph is injected shows a strange change. it becomes hard and assumes a darker coloring, which is not confined to the inoculation spot, but spreads to the neighboring parts until it attains a diameter of from . to cm. in a few days it becomes more and more manifest that the skin thus changed is necrotic, finally falling off, leaving a flat ulceration which usually heals rapidly and permanently without any involvement of the adjacent lymphatic glands. thus the injected tubercular bacilli quite differently affect the skin of a healthy guinea pig from one affected with tuberculosis. this effect is not exclusively produced with living tubercular bacilli, but is also observed with the dead bacilli, the result being the same whether, as i discovered by experiments at the outset, the bacilli are killed by a somewhat prolonged application of a low temperature or boiling heat or by means of certain chemicals. this peculiar fact i followed up in all directions, and this further result was obtained--that killed pure cultivations of tubercular bacilli, after rinsing in water, might be injected in great quantities under healthy guinea pig's skin without anything occurring beyond local suppuration. such injections belong to the simplest and surest means of producing suppurations free from living bacteria. tuberculous guinea pigs, on the other hand, are killed by the injection of very small quantities of such diluted cultivations. in fact, within six to forty-eight hours, according to the strength of the dose, an injection which is not sufficient to produce the death of the animal may cause extended necrosis to the skin in the vicinity of the place of injection. if the dilution is still further diluted until it is scarcely visibly clouded, the animals inoculated remain alive and a noticeable improvement in their condition soon supervenes. if the injections are continued at intervals of from one to two days, the ulcerating inoculation wound becomes smaller and finally scars over, which otherwise it never does; the size of the swollen lymphatic glands is reduced, the body becomes better nourished, and the morbid process ceases, unless it has gone too far, in which case the animal perishes from exhaustion. by this means the basis of a curative process against tuberculosis was established. against the practical application of such dilutions of dead tubercle bacilli there presented itself the fact that the tubercle bacilli are not absorbed at the inoculation points, nor do they disappear in another way, but for a long time remain unchanged, and engender greater or smaller suppurative foci. anything, therefore, intended to exercise a healing effect on the tuberculous process must be a soluble substance which would be liberated to a certain extent by the fluids of the body floating around the tubercle bacilli, and be transferred in a fairly rapid manner to the juices of the body; while the substance producing suppuration apparently remains behind in the tubercular bacilli, or dissolves but very slowly. the only important point was, therefore, to induce outside the body the process going on inside, if possible, and to extract from the tubercular bacilli alone the curative substance. this demanded time and toil, until i finally succeeded, with the aid of a forty to fifty per cent. solution of glycerine, in obtaining an effective substance from the tubercular bacilli. with the fluid so obtained i made further experiments on animals, and finally on human beings. these fluids were given to other physicians to enable them to repeat the experiments. the remedy which is used in the new treatment consists of a glycerine extract, derived from the pure cultivation of tubercle bacilli. into the simple extract there naturally passes from the tubercular bacilli, besides the effective substance, all the other matter soluble in fifty per cent. glycerine. consequently, it contains a certain quantity of mineral salts, coloring substances, and other unknown extractive matters. some of these substances can be removed from it tolerably easily. the effective substance is insoluble in absolute alcohol. it can be precipitated by it, though not, indeed, in a pure condition, but still combined with the other extractive matter. it is likewise insoluble in alcohol. the coloring matter may also be removed, rendering it possible to obtain from the extract a colorless, dry substance containing the effective principle in a much more concentrated form than the original glycerine solution. for application in practice this purification of the glycerine extract offers no advantage, because the substances so eliminated are unessential for the human organism. the process of purification would make the cost of the remedy unnecessarily high. regarding the constitution of the more effective substances, only surmises may for the present be expressed. it appears to me to be derivative from albuminous bodies, having a close affinity to them. it does not belong to the group of so-called toxalbumins, because it bears high temperatures, and in the dialyzer goes easily and quickly through the membrane. the proportion of the substance in the extract to all appearance is very small. it is estimated at fractions of one per cent., which, if correct, we should have to do with a matter whose effects upon organisms attacked with tuberculosis go far beyond what is known to us of the strongest drugs. regarding the manner in which the specific action of the remedy on tuberculous tissue is to be represented, various hypotheses may naturally be put forward. without wishing to affirm that my view affords the best explanation, i represent the process myself in the following manner: the tubercle bacilli produced when growing in living tissues, the same as in artificial cultivations, contain substances which variously and notably unfavorably influence living elements in their vicinity. among these is a substance which in a certain degree of concentration kills or so alters living protoplasm that it passes into a condition that weigert describes as coagulation necrosis. in tissue thus become necrotic the bacillus finds such unfavorable conditions of nourishment that it can grow no more and sometimes dies. this explains the remarkable phenomenon that in organs newly attacked with tuberculosis, for instance in guinea pigs' spleen and liver, which then are covered with gray nodules, numbers of bacilli are found, whereas they are rare or wholly absent when the enormously enlarged spleen consists almost entirely of whitish substance in a condition of coagulation necrosis, such as is often found in cases of natural death in tuberculous guinea pigs. the single bacillus cannot, therefore, induce necrosis at a great distance, for as soon as necrosis attains a certain extension the growth of the bacillus subsides, and therewith the production of the necrotizing substance. a kind of reciprocal compensation thus occurs, causing the vegetation of isolated bacilli to remain so extraordinarily restricted, as, for instance, in lupus and scrofulous glands. in such cases the necrosis generally extends only to a part of the cells, which then, with further growth, assume the peculiar form of riesen zelle, or giant cells. thus, in this interpretation, follow first the explanation weigert gives of the production of giant cells. if now one increased artificially in the vicinity of the bacillus the amount of necrotizing substance in the tissue, the necrosis would spread a greater distance. the conditions of nourishment for the bacillus would thereby become more unfavorable than usual. in the first place the tissue which had become necrotic over a large extent would decay and detach itself, and where such were possible would carry off the inclosed bacilli and eject them outwardly, so far disturbing their vegetation that they would much more speedily be killed than under ordinary circumstances. it is just in looking at such changes that the effect of the remedy appears to consist. it contains a certain quantity of necrotizing substance, a correspondingly large dose of which injures certain tissue elements even in a healthy person, and perhaps the white blood corpuscles or adjacent cells, thereby producing fever and a complication of symptoms, whereas with tuberculous patients a much smaller quantity suffices to induce at certain places, namely, where tubercle bacilli are vegetating and have already impregnated the adjacent region with the same necrotizing matter, more or less extensive necrosis of the cells, with the phenomena in the whole organism which result from and are connected with it. for the present, at least, it is impossible to explain the specific influence which the remedy, in accurately defined doses, exercises upon tuberculous tissue, and the possibility of increasing the doses with such remarkable rapidity, and the remedial effects which have unquestionably been produced under not too favorable circumstances. of the consumptive patients whom he described as temporarily cured, two have been returned to the moabit hospital for further observation. no bacilli have appeared in their sputum for the past three months, and their phthisical symptoms have gradually and completely disappeared. * * * * * can we separate animals from plants? by andrew wilson. one of the plainest points connected with the study of living things is the power we apparently possess of separating animals from plants. so self-evident appears this power that the popular notion scoffs at the idea of science modestly disclaiming its ability to separate the one group of living beings from the other. is there any danger of confusing a bird with the tree amid the foliage of which it builds its nest, or of mistaking a cow for the grass it eats? these queries are, of course, answerable in one way only. unfortunately (for the querists), however, they do not include or comprehend the whole difficulty. they merely assert, what is perfectly true, that we are able, without trouble, to mark off the higher animals from the higher plants. what science inquires is, whether we are able to separate _all_ animals from _all_ plants, and to fix a definite boundary line, so as to say that all the organisms on the one side of the line are assuredly animals, while all the others on the opposite side of the line may be declared to be truly plants. it is exactly this task which science declares to be among the impossibilities of knowledge. away down in the depths of existence and among the groundlings of life the identity of living things becomes of a nature which is worse than confusing, and which renders it a futile task to attempt to separate the two worlds of life. the hopelessness of the task, indeed, has struck some observers so forcibly that they have proposed to constitute a third kingdom--the _regnum protisticum_--between the animal and the plant worlds, for the reception of the host of doubtful organisms. this third kingdom would resemble the casual ward of a workhouse, in that it would receive the waifs and strays of life which could not find a refuge anywhere else. a very slight incursion into biological fields may serve to show forth the difficulties of naturalists when the task of separating animals from plants is mooted for discussion. to begin with, if we suppose our popular disbeliever to assert that animals and plants are always to be distinguished by shape and form, it is easy enough to show him that here, as elsewhere, appearances are deceptive. what are we to say of a sponge, or a sea anemone, of corals, of zoophytes growing rooted from oyster shells, of sea squirts, and of sea mats? these, each and all of them, are true animals, but they are so plant-like that, as a matter of fact, they are often mistaken by seaside visitors for plants. this last remark holds especially true of the zoophytes and the sea mats. then, on the other hand, we can point to hundreds of lower plants, from the yeast plant onward, which show none of the ordinary features of plant life at all. they possess neither roots, stems, branches, leaves, nor flowers, so that on this first count of the indictment the naturalist gains the day. power of movement, to which the popular doubter is certain to appeal, is an equally baseless ground of separation. for all the animals i have above named are rooted and fixed, while many true plants of lower grade are never rooted at all. the yeast plant, the _algæ_ that swarm in our ponds, and the diatoms that crowd the waters, exemplify plants that are as free as animals; and many of them, besides, in their young state especially (e.g., the seaweeds), swim about freely in the water as if they were roving animalcules. on the second count, also, science gains the day; power of motion is no legitimate ground at all for distinguishing one living being as an animal, while absence of movement is similarly no reason for assuming that the fixed organism must of necessity be a plant. then comes the microscopic evidence. what can this wonder glass do in the way of drawing boundary lines betwixt the living worlds? the reply again is disappointing to the doubter; for the microscope teaches us that the tissues of animals and plants are built upon kindred lines. we meet with cells and fibers in both. the cell is in each case the primitive expression of the whole organism. beyond cells and fibers we see the wonderful living substance, _protoplasm_, which is alike to our senses in the two kingdoms, although, indeed, differing much here and there in the results of its work. on purely microscopic grounds, we cannot separate animals from plants. there is no justification for rigidly assuming that this is a plant or that an animal on account of anything the microscope can disclose. a still more important point in connection with this protoplasm question consists in the fact that as we go backward to the beginnings of life, both in animals and plants, we seem to approach nearer and nearer to an identity of substance which baffles the microscope with all its powers of discernment. every animal and every plant begins existence as a mere speck of this living jelly. the germ of each is a protoplasm particle, which, whatever traces of structure it may exhibit, is practically unrecognizable as being definitely animal or plant in respect of its nature. later on, as we know, the egg or germ shows traces of structure in the case of the higher animals and plants; while even lowly forms of life exhibit more or less characteristic phases when they reach their adult stage. but, of life's beginnings, the microscope is as futile as a kind scientific touchstone for distinguishing animals from plants as is power of movement, or shape, or form. a fourth point of appeal in the matter is found within the domain of the chemist. chemistry, with its subtile powers of analysis, with its many-sided possibilities of discovering the composition of things, and with its ability to analyze for us even the light of the far distant stars, only complicates the difficulties of the biologist. for, while of old it was assumed that a particular element, nitrogen, was peculiar to animals, and that carbon was an element peculiar to plants, we now know that both elements are found in animals, just as both occur in plants. the chemistry of living things, moreover, when it did grow to become a staple part of science, revealed other and greater anomalies than these. it showed that certain substances which were supposed to be peculiar to plants, and to be made and manufactured by them alone, were also found in animals. chlorophyl is the green coloring matter of plants, and is, of course, a typical product of the vegetable world; yet it is made by such animals as the hydra of the brooks and ponds, and by many animalcules and some worms. starch is surely a typical plant product, yet it is undoubtedly manufactured, or at least stored up, by animals--a work illustrated by the liver of man himself, which occasionally produces sugar out of its starch. again, there is a substance called _cellulose_, found well nigh universally in plants. of this substance, which is akin to starch, the walls or envelopes of the cells of plant tissues are composed. yet we find those curious animals, the sea squirts, found on rocks and stones at low-water mark, manufacturing cellulose to form part and parcel of the outer covering of their sac-like bodies. here it is as if the animal, like a dishonest manufacturer, had infringed the patent rights of the plant. on the fourth count, then--that of chemical composition--the verdict is that nothing that chemistry can teach us may serve definitely, clearly, and exactly to set a boundary line or to erect a partition wall between the two worlds of life. there yet remains for us to consider a fifth head--that of the food. in the matter of the feeding of the two great living worlds we might perchance light upon some adequate grounds for making up the one kingdom from the other. what the consideration of form, movement, chemical composition, and microscopic structure could not effect for us in this way, it might be supposed the investigation of the diet of animals and plants would render clear. our hopes of distinguishing the one group from the other by reference to the food on which animals and plants subsist are, however, dashed to the ground; and the diet question leaves us, therefore, when it has been discussed, in the same quandary as before. nevertheless, it is an interesting story, this of the nutrition of animals and plants. a large amount of scientific information is to be gleaned from such a study, which may very well be commenced by our having regard to the matters on which a _green_ plant feeds. i emphasize the word "green," because it so happens that when a plant has no chlorophyl (as green color is named in the plant world) its feeding is of diverse kind to that which a green plant exhibits. the mushroom or other fungus may be taken as an illustration of a plant which represents the non-green race, while every common plant, from a bit of grass to an oak tree, exemplifies the green-bearing order of the vegetable tribes. suppose we were to invite a green plant to dinner, the _menu_ would have to be very differently arranged from that which would satisfy a human or other animal guest. the soup would be represented for the plant's delectation by water, the fish by minerals, the joint by carbonic acid gas, and the dessert by ammonia. on these four items a green plant feeds, out of them it builds up its living frame. note that its diet is of inorganic or non-living matter. it derives its sustenance from soil and air, yet out of these lifeless matters the green plant elaborates and manufactures its living matter, or protoplasm. it is a more wonderful organism than the animal, for while the latter can only make new protoplasm when living matter is included in its food supply, the green plant, by the exercise of its vital chemistry, can transform that which is not living into that which is life-possessing. the green plant in other words, raises non-living into living matter, while the animal can only transform living matters into its like. this is why the plant is called a constructive organism, while the animal is, contrariwise, named a destructive one. the result of the plant's existence is to build up, that of the animal's life is to break down its substance, as the result of its work, into non-living matter. the animal's body is, in fact, breaking down into the very things on which the green plant feeds. we ourselves are perpetually dissipating our substance in our acts of life and work into the carbonic acid, water, ammonia, and minerals on which plants feed. we "die daily" in as true a sense as that in which the apostle used the term. and out of the debris of the animal frame the green plant builds up leaf and flower, stein and branch, and all the other tokens of its beauty and its life. if, then, an animal can only live upon living matter--that is to say on the bodies of other animals or of plants--with water, minerals and oxygen gas from the air thrown in to boot, we might be tempted to hold that in such distinctive ways and works we had at last found a means of separating animals from plants. unfortunately, this view may be legitimately disputed and rendered null and void, on two grounds. first of all, the mushrooms and their friends and neighbors, all true plants, do not feed as do the green tribes. and secondly, many of the green plants themselves can be shown to have taken very kindly to an animal mode of diet. a mushroom, thus, because it has no green color, lives upon water, oxygen, minerals, and organic matter. you can only grow mushrooms where there is plenty of animal matter in a state of decay, and as for the oxygen, they habitually inhale that gas as if they were animals. non-green plants thus want a most characteristic action of their green neighbors. for the latter in daylight take in the carbonic acid gas, which is composed of carbon and oxygen. under the combined influence of the green color and the light, they split up the gas into its two elements, retaining the carbon for food and allowing the oxygen to escape to the atmosphere. alas! however, in the dark our green plant becomes essentially like an animal as regards its gas food, for then it is an absorber of oxygen, while it gives off carbonic acid. if to take in carbonic acid and to give out oxygen be held to be a feature characteristic of a plant, it is one, as has been well said, which disappears with the daylight in green plants, and which is not witnessed at all in plants that have no green color. so far, we have seen that not even the food of plants and animals can separate the one kingdom of life from the other. the mushroom bars the way and the green plant's curious behavior by night and by day respectively, in the matter of its gas food, once more assimilates animal life and plant life in a remarkable manner. still more interesting is the fact, already noticed, that even among the green tribes there are to be found many and various lapses from the stated rules of their feeding. thus what are we to say of the parasitic mistletoe, which, while it has grown leaves of its own, and can, therefore, obtain so much carbon food from the air on its own account, nevertheless drinks up the sap of the oak or apple which forms its host, and thus illustrates the spectacle of a green plant feeding like an animal, on living matter? or, what may we think of such plants as the sundew, the venus' fly trap, the pitcher plants, the side saddle plants, the butterworts and bladderworts, and others of their kind, which not only capture insects, often by ingenious and complex lures, but also digest the animal food thus captured? a sundew thus spreads out its lure in the shape of its leaf studded with sensitive tentacles, each capped by a glistening drop of gummy secretion. entangled in this secretion, the fly is further fixed to the leaf by the tentacles which bend over it and inclose it in their fold. then is poured out upon the insect's body a digestive acid fluid, and the substance of the dissolved and digested animal is duly absorbed by the plant. so also the venus' fly trap captures insects by means of its leaf, which closes upon the prey when certain sensitive hairs have given the signal that the animal has been trapped. within the leaf the insect is duly digested as before, and its substance applied to the nutrition of the plant. such plants, moreover, cannot flourish perfectly unless duly supplied with their animal food. such illustrations of exceptions to the rule of green plant feeding simply have the effect of abolishing the distinctions which the diet question might be supposed to raise between animals and plants. we may return to the sundews and other insect catchers; meanwhile, i have said enough to show that to the question, "can we separate animals from plants?" a very decided negative reply must be given. life everywhere exhibits too many points of contact to admit of any boundary line being drawn between the two great groups which make up the sum total of organic existence.--_illustrated london news._ * * * * * the recovery of silver and gold from plating and gilding solutions. in view of the rapid development and extension of the methods of electro-plating with silver and gold, and of the large amount of spent liquors containing silver or gold thus produced, it has long been desirable to find methods by which these metals can be recovered from the spent liquors. the processes hitherto adopted generally necessitate the tedious and unpleasant evaporation of the cyanide liquors, or else involve a series of chemical operations which are somewhat difficult to carry out, so that actually the used-up baths are sold to some firm which undertakes this recovery as a particular branch of its business. a process invented by stockmuir and fleischmann, and worked out by them in the chemical laboratory of the bavarian industrial museum, is, however, exceedingly simple, and is employed in many establishments. in order to remove silver from a potassium cyanide silver solution, it is only necessary to allow a clean piece of plate zinc to remain in the liquid for two days; even better results are obtained by the use of iron conjointly with the zinc. in the first case, the silver often adheres firmly to the zinc, while in the second it always separates out as a powder. it is then only necessary to wash the precipitated powder, which usually contains copper (since spent silver solutions always contain copper), dry it, and then dissolve it in hot concentrated sulphuric acid, water being added, and the dissolved silver precipitated by strips of copper. the silver thus obtained is perfectly pure. if the amount of copper present is only small, it can usually be removed by fusing the precipitated powder with a little niter and borax. in this way a spent silver bath was found to contain per liter st experiment . grms. d " . " ------ mean . " the presence of silver could not be qualitatively ascertained in the residual liquor. although sheet zinc, or zinc and iron sheets, serve so well for the precipitation of silver, they cannot be employed for the recovery of gold. the latter separates out in such a case very incompletely and as a firmly adhering lustrous film in the zinc. on the other hand, finely divided zinc, the so-called zinc dust, is an excellent substance to employ for precipitating gold quantitatively and in the form of powder from spent cyanide liquors. when zinc dust is added to a spent gold bath and the liquid periodically stirred or shaken, all the gold is precipitated in two or three days. the amount of zinc to be added naturally depends on the quantity of gold present. freshly prepared gold baths for gilding in the cold contain on the average . grms. gold per liter, while those used for the hot process contain . grms. to precipitate all the gold in the original bath, . grms. or . - . grms. zinc dust would be necessary, and, of course, a much smaller quantity would be sufficient for the spent liquors. since the precipitation takes place more rapidly when an excess of zinc dust is present, it is generally advisable to add ¼ or at the most ½ kilo, of zinc dust to every liters of solution. the precipitated gold, which contains zinc dust and usually silver and copper, is washed, freed from zinc by hydrochloric acid, and then from silver and copper by nitric acid and thus obtained pure. a spent bath treated in this way gave the following amounts of gold per liter: st experiment . d " . mean . grms. the presence of gold in the residual cyanide solution could not be qualitatively detected. the potassium cyanide of the solutions obtained by this process should be converted into ferrocyanide by heating with ferrous sulphate and milk of lime, since this substance is not poisonous and can therefore be got rid of without danger. it would, however, be more economical and, considering the large amount 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[new series.] _thirty-fourth year_. new york, saturday, march , . * * * * * contents. (illustrated articles are marked with an asterisk.) africa crossed again aluminum barometer, aneroid bolt, door, improved* bread, snow-raised buffalo, domestication of the carpet beetle, remedy for the chimney flues clocks, pneumatic cooper, peter, as an inventor crusher, ore, novel* electricity, statical, phenom. in flour, banana furnace, imp., for burn'g garbage* hardware, english & american ice cave of decorah, iowa inventions, new agricultural iron, advance in light, albo-carbon magnetism, curious facts in motor, gary, the* natural science, charms of neutral line, gary's notes and queries patent laws patents, american, recent pen, stencil, new* people, a strange phosphorescence plants protected by insects pleuro-pneumonia railway, vesuvius reading and eyesight reading, taste for regulator, engine, novel* spain a field for machinery sponges, glass* table, ironing, new* telegraph, writing telegraph, writing, cowper's telegraphy, ocean, progress of tiller, steam, new* tree, pottery vase, greek, ancient* * * * * * table of contents of the scientific american supplement no. , for the week ending march , . price cents. for sale by all newsdealers. i. engineering and mechanics.--the herreshoff torpedo boat, recently built at bristol, r. i., for the british government. the novelties in the placing of the screw, etc. the peculiar boiler. figures.--improved hopper steam dredger. figures.--the st. gothard tunnel.--the beacon tower of lavezzi. figures. ii. architecture.--bath abbey church. full page illustration. iii. technology.--the achison stone cutting machine. engraving.--the deep mines of the world.--shoemakers' wax.--gruber's new method of germination. engraving.--improved process for treating wood, etc., for paper manufacture.--bronzing plaster of paris casts.--sal soda for unhairing hides and skins.--sieburger's paste.--to tan lace leather with softsoap. practical dyeing recipes: blue white zephyr, scotch blue on worsted, scotch green on worsted, jacquineaux on worsted, drab on worsted, gold on venetian carpet yarn, red brown slubbing, scarlet braid, slate braid, light drab on cotton, blue on cotton, brown on cotton, chrome orange on cotton carpet yarn, black on common mixed carpet yarn for filling, black on cotton and wool mixed yarn. damar varnish for negatives.--to make vignetters by means of gelatino-chromate.--resorcine colors.--phosphate soaps.--substitution of different metals in ultramarine colors.--a harmless green for paper hangings.--siegwart's bath for etching glass.--composition of french bronzes.--a new enemy to the tea plant.--the bradford oil sand. iv. chemistry and metallurgy.--apparatus for titration, figure.--palladium.--hæmocyanin.--test for alcohol in ethereal oils and chloroform.--reaction of tartaric and citric acid.--a peculiar observation.--insolubility of iodate of lead.--mode of preventing the contamination of water with lead.--separating phosphorus from iron and steel.--production of alcohol without fermentation. v. electricity, light, heat, etc.--some facts in regard to telescopic and stereoscopic vision.--the centenary of the birth of sir humphry davy. his boyish days. his first chemical experiments. his first lecture at the royal institution. a very entertaining biographical sketch.--light and heat in gas flames.--nickel needles for compasses.--the nature of the elements.--a new compound prism for direct vision spectroscopes. vi. medicine and hygiene.--filaria in the eye. by chas. s. turnbull, m. d.--the species of tapeworm now prevalent.--nitrous oxide under pressure. vii. natural history, geology, etc.--a gigantic american deep-sea crustacean, engraving.--glaciers in the united states.--the toulomne cave.--archæological explorations in tennessee. by f. w. putnam. figures.--memorably cold winters.--life at timber line. by professor c. e. robins, summit, colorado.--the walled lake in iowa. viii. astronomy.--is the moon inhabited? by camille flammarion. the various opinions that have been held in regard to the moon. the best we can do with our present telescopes. the means we possess for judging of the condition of the moon. recent changes on the moon. photographs of the moon and their defects. facts that have been observed by the persevering eyes of astronomers. * * * * * a new steam tiller. steam is now made to perform almost everything in the way of heavy labor, to the saving of muscle and energy that may be more profitably employed; and since inventive genius has devised means of governing steam with absolute accuracy, there seems to be no limit to its economical application. a recent invention in steam engineering, which exhibits in a marked degree the controllability and adaptability of steam, is mr. herbert wadsworth's steam tiller, an engraving of which we present herewith. [illustration: fig. , , .] this machine (fig. ) is provided with a steam cylinder, similar to the cylinder of a steam engine, containing a piston, the rod of which is attached to a crosshead, a, that slides on ways, b, secured to the bed supporting the cylinder. the tiller, d, as it is carried to starboard or port, slides through a socket, e, pivoted to the crosshead. the motion of the rudder is communicated to the steam cut-off by means of the shaft, c, crank, j, rod, k, crank, i, and the hollow valve spindle. when the tiller is amidships the valve handle, h, is at right angles to the cylinder, and parallel to the tiller. by moving the lever, h, to right or left, steam is admitted to one end or the other of the cylinder, which, acting on the tiller through the piston, piston rod, and crosshead, moves the rudder; and when the rudder reaches the desired position the cut-off will have been moved the amount necessary to prevent further entrance of steam. when the rudder is influenced by the waves or by the expansion or contraction of steam, the cut-off alters its position in relation to the valve and automatically arranges the steam passages so that the piston is returned to its proper position. the details of the cut-off are shown in fig. ; the valve, g, which covers the cut-off, f, acts like a four way cock. the spindle of the cut-off, f, is connected with the lever, i, and is moved by the rudder, as already described. by enlarging or gradually narrowing the ends of the steam ports great rigidity or elasticity may be given to the hold of this engine, according to the requirements of the particular vessel. few and simple as are the parts of this machine it is possible, by balancing the valves and suiting the diameter of the cylinder to the work to be performed, to overcome great resistances with a slight effort. the inventor says that this system of valves is considered by experts to be novel and very valuable. in fig. is shown a pattern of a slide valve suited to special purposes. its working is essentially the same as that of the valve already described. the ports are set side by side, parallel with the sides of the valve. the supply port is in the middle, the other ports lead to opposite ends of the cylinder. [illustration: fig. .] in fig. is shown another application of the controlling valve and cut-off described above. two oscillating steam cylinders are employed in working the rudder. they are placed on opposite sides of the chest, a, and are supplied with steam through the controlling valve, b. the piston rods of the two cylinders are connected with cranks placed on opposite ends of the shaft, c, at right angles to each other. upon this shaft, half-way between the pillow blocks which support it, there is a worm which engages a toothed sector, d, on the rudder-post, e. to an extension of the rudder-post is secured an arm, f, which is connected with the arm, g, of the controlling valve. by shifting the lever, h, the supply of steam to the two cylinders may be increased or diminished, or its direction may be changed, so that the engines will be reversed or stopped. this engine is remarkable for its simplicity. the cylinders may be detached and changed if required, one size of bed answering for three different sizes of cylinder, which may vary only in diameter, the stroke being the same, so that the castings for engines of different power are the same except in the matter of the cylinders and pistons, and all the parts are interchangeable--a feature of modern engine building that cannot be too highly valued. further information may be obtained from herbert wadsworth, merchants' bank building, state street, boston, mass. * * * * * how our patent laws promote and improve american industries. on another page we print in full a most suggestive paper recently read before the manchester (eng.) scientific and mechanical society, by mr. frederick smith, a prominent builder of that city, contrasting the qualities, styles, and prices of american and english builders' hardware--a paper which the _ironmonger_ pronounces one of the most serious indictments yet preferred against british workmanship in that department. the field covered by the paper--the supplying of house builders' hardware--embraces a multitude of conveniences, but no real necessities. why is it that america has been prolific in novel devices and clever improvements in this department of manufacture as in so many others, while england has gone on stolidly copying ancient forms, changing only to cheapen by the introduction of poor material and sham construction? mr. smith mentions several reasons that english manufacturers have given him for the state of things he, as an englishman, so greatly deplores; but evidently he is not satisfied with any of them, and very justly; for none of them touches the real cause--the radically different attitude of the public mind toward inventions, characteristic of the two countries. in england the user of household inconveniences accepts them as matters of fact; or if he grumbles at them he never thinks of trying to change them. it is not his business; and if he should devise an improvement, ten to one he could not get it made. to patent it is practically out of the question, for if it were not condemned off-hand as trivial, the patent fees would make it cost more than it was likely to be worth. the mechanic who makes such things is trained to work to pattern, and not waste his time on experiments. besides, if he should make a clever invention he would not be able to raise the necessary fees for a patent, or to get any one to help him thereto. the manufacturer "makes what his customers call for." why should he spend his money and spoil his plant to introduce improvements? so things go, until some pestilent yankees flood the markets with better articles at a lower price; and british consumers suddenly discover that they want something that the native manufacturer cannot make. the need was there; but invention did not follow. how happened it that the american manufacturer did not pursue the same uninventive course? what produced the radically different attitude of the american mind toward newfangled notions out of which inventions proceeded and flourished? no doubt several causes have been at work: freedom of thought and action; popular education; a blending of races; and the tide of adventurous spirits naturally resorting to a new and free land. these have had their influence undoubtedly; but all these have existed, more or less completely, in other new lands, without that outburst of creative energy which has made america the nursery of inventions, great and small. the determining cause, the one condition that prevailed here and not elsewhere, was the circumstance that almost from the start new ideas were given a market value in this country. unlike all others, the american patent law directly encouraged independent thinking in all classes. the fees were low and the protection offered fairly good. men soon found that it paid to invent; that one of the surest roads to competency was a patented improvement on something of general use. if a household utensil or appliance went wrong or worked badly, every user was directly interested in devising something better; and, more than that, he was interested in making his invention known and in securing its adoption. the workman at his bench had an ever-present inducement to contrive something at once cheaper and better than the article he was hired to make. he could patent his improvement, or the wholly original device he might hit upon, for a few dollars; and his patent would count as capital. it would make him his own master, possibly bring him a fortune. the manufacturer could not rest contented with the thing he set out to make, for the meanest hired man in his employ might suddenly become a competitor. he must be constantly alert for possible improvements, or his rivals would get ahead of him. the result is a nation of inventors, at whose hands the newest of lands has leaped to the leadership in the arts, almost at a bound. there is talk of changing all this; of emulating the conservative spirit of the old world; of putting inventors under bonds; of stopping the rush of industrial improvement--to enable a few short-sighted yet grasping corporations to get along without paying license fees for such inventions as they happen to approve of. they profess to want inventors to go on making improvements. they are willing to ascribe all honor to the successful inventor; but they are determined not to pay him for his work. still more they are determined to change the attitude of the public mind toward inventors and inventions, if such a change can be wrought by plausible misrepresentations. the fact that they were able to inveigle one branch of the american congress into assenting to their unjust and mischievous scheme is one of the anomalies of our recent history. it should be taken as a timely warning of impending danger to all the industrial interests of the country. it is outrageous that the inventors of the land, after having raised their country to the first rank among industrial nations, should have to defend their constitutional rights against congressional invasion; but the fact exists; and the defense should be made a matter of personal interest and effort not only by every inventor and manufacturer, but by every honest citizen. * * * * * pleuro-pneumonia. the cattle plague, which is creating so much anxiety throughout the eastern states, is a contagious fever, affecting cows chiefly, characterized by extensive exudations into the respiratory organs, and attended by a low typhus inflammation of the lungs, pluræ, and bronchia. it has prevailed in europe for ages, at times developing into wide-spread scourges, causing incalculable loss. it was imported into england in , and again three years later; and it was estimated that within twenty-five years thereafter the losses by deaths alone in england had amounted to $ , , . in the disease was carried to australia by an english cow, and, spreading to the cattle ranges, almost depopulated them. in an infected dutch cow brought the disease to brooklyn, where it has since lingered, slowly spreading among the cattle in kings and queens counties. in several head of infected english cattle were imported into new jersey, and, spreading among a herd of valuable cattle, made it necessary for them all to be slaughtered, the only certain method of stamping out the disease. in four infected cows were imported into massachusetts from holland; the plague spread rapidly, and was stamped out only by persistent effort, the state paying for over , slaughtered cattle. since the disease has not been known there. meantime the pest had invaded eastern pennsylvania, delaware, and maryland, where it has since prevailed in isolated localities. the absence of large herds of moving cattle in these districts, except for speedy slaughter, has prevented the disease from developing into a general plague. the recent action of the british council in forbidding the importation of american live cattle is likely to prove of inestimable benefit to this country, in forcibly calling attention to the grave risk that the presence of the disease on long island and elsewhere constantly entails. fortunately the drift of the cattle traffic is eastward, and as yet there has been no propagation of the poison in the great cattle ranges of the west. unless summarily arrested, however, the disease will surely reach those sources of our cattle supply, and occasion losses that can be estimated only in hundreds of millions of dollars. the experience of all countries into which this disease has gained access appears to prove that there is only one way of getting rid of it--namely, the immediate killing of all infected cattle, and the thorough disinfection of the premises in which they are found. the disease is purely infectious, and is never found in regions where it has not gained a foothold by importation. palliative measures have in every instance failed to eradicate the disease, and are only justifiable, as in australia, after the plague has reached dimensions utterly beyond the reach of any process of extermination. professor law, of cornell university, one of our best informed veterinary surgeons, most emphatically opposes every attempt to control the disease by quarantining the sick or by the inoculation of the healthy. "we may quarantine the sick," he says, "but we cannot quarantine the air." to establish quarantine yards is simply to maintain prolific manufacturers of the poison, which is given off by the breath of the sick, and by their excretions, to such an extent that no watchfulness can insure against its dissemination. besides, the expense of thorough quarantining operations would amount to more than the value of the infected animals whose lives might be saved thereby. inoculation is still less to be tolerated at this stage of the pest. the professor says: "germany, holland, belgium, france, and england, have been treating the victims of this plague for nearly half a century, but the result has only been the increase of disease and death. our own infected states have been treating it for a third of a century, and to-day it exists over a wider area than ever before. contrast this with the results in massachusetts and connecticut, where the disease has been repeatedly crushed out at small expense, and there can be no doubt as to which is the wisest course. as all the plagues are alike in the propagation of the poison in the bodies of the sick, i may be allowed to adduce the experience of two adjacent counties in scotland when invaded by the rinderpest. aberdeen raised a fund of £ , , and though she suffered several successive invasions, she speedily crushed out the poison wherever it appeared by slaughtering the sick beasts and disinfecting the premises. the result was that little more than half the fund was wanted to reimburse the owners for their losses, and the splendid herds of the county were preserved. forfar, on the other hand, set herself to cure the plague, with the result of a universal infection, the loss of many thousands of cattle, and the ruin of hundreds of farmers. finally the malady was crushed out in the entire island by the method adopted by aberdeen and other well advised counties at the outset." and again, "cattle have been inoculated by the tens of thousands in belgium and holland, and of all europe these are the countries now most extensively infected. france, prussia, italy, austria, and england have each practiced it on a large scale, and each remains a home of the plague. australia has followed the practice, and is now and must continue an infected country. our own infected states have inoculated, and the disease has survived and spread in spite of it, and even by its aid. whatever country has definitively exterminated the plague (norway, sweden, denmark, holstein, mecklenburg, switzerland, massachusetts, and connecticut), that country has prohibited inoculation and all other methods that prevail on the principle of preserving the sick, and has relied on the slaughter of the infected and the thorough disinfection of their surroundings. so will it be with us. if any state adopts or allows any of these temporizing measures, that state will only repeat the experience of the past alike in the old world and the new, will perpetuate the disease in the country, will entail great losses on its citizens, will keep up the need for constant watchfulness and great expense by the adjoining states for their own protection, and will indefinitely postpone the resumption of the foreign live stock trade, which, a few months ago, promised to be one of the most valuable branches of our international commerce." we are persuaded that the position taken by professor law, and other similar-minded veterinary surgeons, is the only safe one. the disease can be stamped out now with comparatively small loss. if trifled with, and tolerated, it cannot but result in a great national calamity. * * * * * spain a field for machinery and patents. from a too lengthy communication to admit in full to our columns, a resident of madrid communicates to the scientific american some facts relative to the fertility of the soil of spain, her necessity for improved agricultural and other implements, and closes with the assertion that it is a good field withal for patents. we cull from the letter as follows: i have lived, says the writer, for a number of years in this beautiful country, so little understood by foreigners, so little appreciated by its own inhabitants. the spain of romance, poetry, and song, is the garden as well as the california of europe. but it stands in great need of the health-giving touch of the north american enterprise. we have here the same mineral treasures, the same unrivaled advantages of climate, that made spain once the industrial and commercial emporium of the world. but spain is awakening. she is endeavoring to shake off her lethargy. the late exhibition of paris has proved this; and those who are familiar with the past history and present condition of spain have been astonished at the result of this effort. a new era has commenced for the country, and it is everywhere evident that a strong current of enterprise and industry has set in. but it is with nations, as with individuals, when they have remained long in complete inaction, brain and muscles are torpid and cannot at first obey the will. spain needs the assistance of other nations hardened and inured to toil. the plows now used to till the land are precisely such as were those left by the moors in the unfinished furrow, when with tears and sighs they bade farewell to their broad fields, their mosques and palaces, whose ideal architecture is still the wonder of the world, to go forth as outcasts and exiles in obedience to the cruel edict that drove them away to the deserts of africa. i doubt whether there is an american plow in spain, much less a steam plow. sowing and reaping machines are here unknown, and grain is tread out by oxen and mules just as it was in scripture times, and cleaned by women, who toss it in the air to scatter the chaff. everything is primitive and oriental here as yet. spain could supply all europe with butter and cheese, and, on the contrary, these articles are imported in large quantities from england, holland, and switzerland. the traveler crosses leagues and leagues of meadow land where not a tree is to be seen, nor one sheep pasture, and which are nevertheless watered by broad rivers that carry away to the ocean the water that would, by irrigation, convert these fields into productive farms. there are many places in spain where the wine is thrown away for want of purchasers and vats in which to keep it. in the upper aragon, the mortar with which the houses are built is made with wine instead of water, the former being the most plentiful. aragon needs an enterprising american company to convert into wholesome table wine the infinite varieties there produced, and which our neighbors the french buy and carry away to convert into bordeaux. we want american enterprise in galicia and asturias, where milk is almost given away, to convert it into the best of butter and cheese; and also in those same provinces, where delicious fruit is grown in such abundance that it is left on the ground for the swine. spain needs many more railroads and canals, all of which, when constructed, are subsidized by the government; the railroads at the rate of $ , a kilometer, and many more additional advantages are offered for canals. with regard to commerce with spain, we have to lament the same indifference on the part of the americans. i have, for instance, an american double-burner petroleum lamp. all who see it admire and covet it, but they are not to be had here. if we except one american in madrid, who brings mostly pumps and similar articles on a very small scale, we have no dealers in american goods here. wooden clothes pins, lemon squeezers, clothes horses, potato peelers, and the hundreds of domestic appliances of american invention, elsewhere considered indispensable, are in spain unknown. we had confidently expected that the new spanish law on patents would draw the attention of american inventors toward this country, that to-day offers a wide field for every new practical invention, but i am sorry to see that, with the exception of edison and a few others, the americans have not yet availed themselves of the easy facility for taking patents for spain, where new inventions and new industries are now eagerly accepted and adopted. and while the americans are thus careless as to their own interests, the french take out and negotiate, in spain, american patents with insignificant variations. let american inventors be assured that any new invention, useful and practical, and above all, requiring but little capital to establish it as an industry, will find a ready sale in spain. i could enlarge to a much greater extent upon the indifference of american inventors, merchants, manufacturers, and business men, as to the market they have in spain in their respective lines, and upon the importance of building up a trade with this country, but to do so would require more space than i think you would feel justified in occupying in your columns. * * * * * peter cooper as an inventor. the successes of peter cooper's long and useful life are well known. not so many are aware of his varied experience in the direction of failure, particularly in the field of invention. more than once he has found his best devices profitless because ahead of his time, or because of conditions, political or otherwise, which no one could foresee. he possessed the rare qualities, however, of pluck and perseverance, and when one thing failed he lost no time in trying something else. before he was of age he had learned three trades--and he did not make his fortune at either. in a familiar conversation with a _herald_ writer recently, mr. cooper related some of his early experiences, particularly with reference to enterprises which did not succeed. his father was a hatter, and as a boy young cooper learned how to make a hat in all its parts. the father was not successful in business, and the hatter's trade seems to have offered little encouragement to the son. accordingly he learned the art of making ale. why he did not stick to that calling and become a millionaire brewer, mr. cooper does not say. most probably the national taste for stronger tipple could not at that time be overcome, and ale could not compete with new england rum and apple-jack. the young mechanic next essayed the art of coachmaking, at which he served a full apprenticeship. at the end of his time his employer offered to set him up in business, but the offer was not accepted, through fear of losing another's money. he felt that if he took the money and lost it he would have to be a slave for life. so he quit coachmaking and went to work for a man at hempstead, l. i., making machines for shearing cloth. in three years, on $ . a day, cooper had saved enough money to buy his employer's patent. immediately he introduced improvements in the manufacture and in the machine, which the war with england made a great demand for by excluding foreign cloths. at this time cooper married. in due time the family numbered three, and the young father's inventive faculty was again called upon. "in those days," said mr. cooper to the reporter, smiling as the remembrance came to his mind, "we kept no servants as they do nowadays, and my wife and myself had to do all that was to be done. after our first child was born i used to come into the house and find my wife rocking the cradle, and i relieved her from that while i was there. after doing that for a few days i thought to myself that i could make that thing go of itself. so i went into my shop, and made a pendulous cradle that would rock the child. then i attached a musical instrument which would sing for it, and at the same time the machine would keep the flies off. the latter was very simple; by hanging something to the cross bar, as the cradle swung under it, backward and forward, it would create wind enough to drive away the flies. the machine was wound up by a weight, and would run for nearly half an hour without stopping. i took out a patent for it, and one day a peddler came along with a horse and wagon, as they do in the country, and saw the cradle. he struck a bargain with me and bought the patent right for the state of connecticut, giving for it his horse and wagon and all the goods he had with him. they afterward made some there, but nothing like as good as mine. it was a beautiful piece of furniture," said mr. cooper regretfully, as he thought of it as a thing of the past. "they afterward substituted springs for the weight movement, but that kind was not so good." about this time the war with england ended and the market was spoiled for the shearing machines. then, we believe, mr. cooper tried his hand at cabinetmaking, but that failed, and he set up a grocery store where the bible house now stands. while selling groceries mr. cooper made an invention which ought to have made his fortune, but it did not. the story is best told in mr. cooper's own words: "it was just before the erie canal was completed, and i conceived a plan by which to tow boats by the use of all the elevated waters on the line of the canal. to demonstrate that that was practicable i made with my own hands a chain two miles long, and placed posts feet apart in the east river from bellevue dock down town about a mile. these posts supported grooved wheels to lay the chain in, forming an endless chain. the whole was moved by an overshot waterwheel placed at the bellevue dock. a reservoir twelve feet square and three deep held the water to turn the wheel." at the suggestion of governor clinton mr. cooper tightened his chain and pulled up the end post just before the grand trial of his device was to come off. he succeeded in getting stone enough to anchor the post, however, and the experiment went off swimmingly. the boat was hooked on to the chain, and the passage back and forward--two miles--was made in eleven minutes. "i ran that boat some ten days," says mr. cooper, "to let people see what could be done, and carried nearly a thousand people. part of the time i ran two boats. once i counted people in one boat. i made the whole chain myself and planted the posts. as i could find no wheels to suit me i made the moulds and cast the wheels myself out of block tin and zinc. it was no small job, i can tell you." this was unquestionably a grand invention. in itself it was a perfect success; but it was not used. mr. cooper tells why: "it demonstrated completely that the elevated water power along the line of the canal and every lock in the canal could be made use of to drive the boats. governor clinton gave me $ for the privilege of buying the right to the plan in case he should want to use it on the erie canal. in making the canal he had promised the people along the route that as soon as it was finished they could sell their horses to tow the boats, their grain and fodder to feed the horses, and their provisions for the passengers. on reflection he thought that if he took all that away from them he would have to run the gantlet again, and he could not afford to do that. there never was anything done with the plan until a few years ago, when mr. welch, president of the camden and amboy railroad and canal, invented exactly the same thing and put it in practice on his locks on the canal. he found it saved half the time and great expense. he went to washington to take out a patent for it, and when he got there he found that i had patented the same thing fifty-three years before. my patent had run out, so he could use the plan on his canal. it has also been used on one lock on the erie canal. if they could have used that chain on the whole length of the erie canal it would have saved many millions of dollars." this would not be a bad place, were there room for it, to speak of "undeveloped" and therefore worthless inventions; and the assumption that if an inventor does not make his invention immediately profitable it must be good for nothing, and should be dispatented. but the moral goes without telling. mr. cooper's next attempt at invention was made about the same time, but in quite a different direction. it was during the struggle of the greeks for independence, and wishing to do something for their assistance, mr. cooper undertook to make a torpedo boat for them. mr. cooper says: "it was a small one that could be taken on board ship and used to destroy any vessel that came to destroy them. it was fixed with a rotary steam engine and a screw wheel to propel it. it was intended to be guided from the ship or the shore. there were two steel wires fixed to the tiller of the rudder, and the operator could pull on one side or the other and guide the vessel just as a horse is guided with reins. it was so arranged that at night it would carry a light with its dark side toward the object to be destroyed, and by simply keeping the light in range with the vessel it would be sure to hit it. the torpedo was carried on a little iron rod, projecting in front of the torpedo vessel a few inches under water. contact would discharge the torpedo and bend this iron rod. this would reverse the action of the engine and cause the torpedo vessel to return right back from whence it came, ready to carry another torpedo." unfortunately the torpedo boat was not ready in time to go with the ship carrying the contributions for greece. it was stored in mr. cooper's factory (he had then turned his attention to glue) and was destroyed by the burning of the factory. it seems to have been quite a promising affair for the time. mr. cooper says: "i experimented with it at once to see how far it could be guided. i made a steel wire ten miles long and went down to the narrows to test the matter. i had steel yards fastened to one end of the wire, and to the other end the torpedo vessel as attached. it got about six miles away when a vessel coming into the harbor crossed the wire and broke it. although the experiment was not complete it showed that for at least six miles i could guide the vessel as easily as i could guide a horse." mr. cooper's work as the pioneer locomotive builder in this country; his later inventions and improvements in the manufacture of railway iron and wrought iron beams for fireproof buildings; his application of anthracite coal to iron puddling, and his other successes are almost as widely known as his philanthropic efforts for the education and advancement of the industrial classes of this city. after all, we are not sure but the story of his long and varied and always honorable career, told by himself, would not be worth, to young people who have to make their way in life through many difficulties, more even than the advantages of the noble institution which bears his name. * * * * * taste for reading.--sir john herschel has declared that "if he were to pray for a taste which should stand under every variety of circumstance and be a source of happiness and cheerfulness to him through life, it would be a taste for reading." give a man, he affirms, that taste, and the means of gratifying it, and you cannot fail of making him good and happy; for you bring him in contact with the best society in all ages, with the tenderest, the bravest, and the purest men who have adorned humanity, making him a denizen of all nations, a contemporary of all times, and giving him a practical proof that the world has been created for him, for his solace, and for his enjoyment. * * * * * africa crossed again. information has been received by way of lisbon, march , that the portuguese explorer, pinto, has succeeded in traversing africa from west to east, and has reached transvaal. the latitude of his course across is not mentioned. * * * * * curious facts in magnetism. at the meeting of the new york academy of sciences february th, the article in the march number of _harper's magazine_, entitled "gary's magnetic motor," was incidentally alluded to, and prof. c. a. seeley made the following remarks: the article claims that mr. gary has made a discovery of a neutral line or surface, at which the polarity of an induced magnet, while moving in the field of the inducing pole, is changed. the alleged discovery appears to be an exaggerated statement of some curious facts, which, although not new, are not commonly recognized. if a bar of iron be brought up, end on, near a magnetic pole, the bar becomes an induced magnet, but an induced magnet quite different from what our elementary treatises seem to predict. on the first scrutiny it is a magnet without a neutral point, and only one kind of magnetism--namely, that of the inducing pole. moreover, the single pole is pretty evenly distributed over the whole surface, so that if iron filings be sprinkled on the bar they will be attracted at all points and completely cover it. now, if while the bar is covered by filings it be moved away from the inducing pole, the filings will gradually and progressively fall, beginning at the end nearest the inducing pole and continuing to some point near the middle of the bar; the filings at the remote end will generally be held permanently. when the bar is carried beyond the field of the inducing pole it is simply a weak magnet of ordinary properties--_i. e._, of two poles and a neutral point between them. a plausible and simple explanation of this case is that the inducing pole holds or binds the induced magnetism of opposite name, so that it has no external influence; the two magnetisms are related to each other as are the positive and negative electricities of the leyden jar. let the inducing pole be n.; the s. of the bar will be attracted by it and bound, while the n. of the bar becomes abnormally free and active. on moving the bar from the pole the bound magnetism is released and a part becomes residual magnetism. now when the residual balances the free magnetism which is of opposite name, we are on gary's neutral line. in a restricted sense there is a change of polarity over the half of the bar contiguous to the inducing pole; on the other half there is no change of pole in any sense. experiment with a shingle nail in the place of the filings, _à la_ gary, bring the nail to the induced bound pole, and it may be held, except at the neutral line. now if one will read the magazine article with such ideas as these he will feel pretty sure that the writer of it has used words recklessly, that gary has not made an original discovery, and that the "neutral" line, whatever it be, has only an imagined relation to the "principle" of the motor. the gary motor as a perpetual motion scheme, of course, is not worthy of serious notice from a society devoted to science. it has no noteworthy novelty of construction or conception. mr. gary is afflicted with the very old delusion of the cut-off or shield of magnetism, which is to cost less than what comes from it. his cut-off is a sheet of iron, which we know acts simply as an armature. * * * * * a new phenomenon in statical electricity. m. e. duter, in a paper read before the french academy in december, showed that when a leyden jar is charged with either positive or negative electricity its internal volume increases, and that this effect is a new phenomenon, unexplainable by either a theory of an increase of temperature or of an electrical pressure. the experiment was performed by means of a flask-shaped leyden jar with a long tube attached to its neck, and containing a liquid which served as the inner armature. the author's attention had been called to the fact that this phenomenon had been observed ten years ago by m. gori. his researches, just made public, leave no doubt of the accuracy of m. duter's view, that the glass of the jar really expands. according to the theory of elasticity, the effect of an internal pressure in a hollow sphere is in the inverse ratio of its thickness. m. duter, therefore, had three flasks made of the same volume, but of thicknesses of mm., . mm., and . mm. respectively. they were filled with water and enveloped by tin foil. each carried a capillary thermometer tube, in which the variations of the height of liquid served to measure the changes in volume due to electrification. he found that these changes were imperceptible in the thick glass, very marked in the flask of mean thickness, and rose to mm. in the thinnest. the variations in volume were very nearly in inverse ratio of the square roots of the thicknesses. * * * * * a new ore crusher. the accompanying engravings represent an improved ore crusher, which is said to be very effective and economical in the use of power. [illustration: fig. .--brown's ore crusher.] [illustration: fig. .--horizontal section.] a short vertical cast iron cylinder, a, having in one side a discharge opening, h, contains all of the movable parts. the upper portion of the cylinder is lined with chilled iron plates, l, and an inclined chute, x, leads to the discharge opening, h. a rigid shaft, b, carries the circular crusher, c, and moves in a ball and socket joint at the upper end, and extends eccentrically through the boss of a bevel wheel, g, at its lower end, and rests on a step supported by a lever that may be adjusted by the screw, r. the wheel, g, is driven by the pinion, p, on whose shaft there are a pulley and a fly-wheel. the double gyratory motion of the crusher, c, causes it to approach all portions of the lining, l, crushing whatever lies between. it is said that this machine is capable of crushing tons of the hardest ore per hour. its weight is , lbs.--_musée de l'industrie._ * * * * * recent american patents. enos richmond, of troy, n. y., has invented a steak tenderer, having a plunger studded with chisel-pointed rods, and arranged in a case in connection with an elevating spring. a blow upon the knob at the top of the plunger forces the chisel-pointed rods through holes in the casing into the meat, the casing resting on the surface of the steak. messrs. a. w. southard and volney r. sears, of falls city, neb., have patented an improved invalid bedstead, which is provided with ingenious mechanism for placing the invalid in different positions. an improved spring attachment for carriage tops, which is designed to prevent the rear bow from being bent by the weight of the top when turned back, has been patented by mr. robert e. mccormick, of doylestown, o. mr. espy gallipher, of schellsburg, pa., has devised an axle journal having a groove lengthwise upon its upper side which extends back upon the surface of the axle and communicates with an oil cup. a sliding rod occupies a portion of the groove; when this rod is drawn out it permits the oil to fill the groove; when it is pushed into the groove in the axle, the oil is ejected and a further supply is cut off. an improved pill machine, invented by messrs. w. n. fort and r. r. moore, of lewisville, ark., is adapted to the manufacture of pills in large quantities. the machine has mechanism for grinding and mixing ingredients, a grooved wheel and trough for forming the pills, and a device for applying powder. an improvement in millstone adjustments has been patented by mr. stephen p. walling, of south edmeston, n. y. this invention consists in a screw applied to the end of the mill spindle on which the stone is rigidly held, so that the running stone may be forced by the screw away from the stationary stone and held against the action of a spring at the opposite end of the spindle, the object being to prevent the stones from becoming dulled by contact with each other. an improved attachment for sewing machines for soaking or waxing the thread as it passes the needle, has been patented by mr. pedro f. fernandez, of san juan, porto rico. the invention consists in a frame secured to the arm of a sewing machine by a thumb-screw, and provided with a clamping device for holding wax or soap. a novel combination of a toggle and springs and levers for operating a drag saw has been patented by mr. harvey hughes, of wheat ridge, ohio. the saw, while properly guided, is free to move up or down without affecting the leverage. an improvement in filters, which consists in re-enforcing the felt disk with a backing of wire cloth to enable it to resist heavy water pressure, has been patented by mr. b. p. chatfield, of aiken, s. c. a basket having light sheet metal sides attached to a wooden bottom by crimping the edges over a rib on the periphery of the bottom, has been patented by mr. samuel friend, of decatur, ill. the handle and lid may be easily removed to permit of packing and storage. an improved cross bar for fastening doors, patented by mr. richard condon, of la salle, ill., has a spring acted portion which engages a socket on the door casing, and is retained in that position by a spring catch. * * * * * a new ironing table. the accompanying engraving represents a convenient and inexpensive table recently patented by mr. albert h. hogins, of morrisania, n. y. it is more especially designed for ironing, but it may be used for other purposes when closed up. the top is made in two tapering sections, a b. the section, b, is narrower than the other, and is pivoted at its wider end to a bar, e, which slides into a socket formed in the table. the table has five legs, one of which, d, is attached to a sliding rail that supports the narrower end of the movable part of the top. the table is provided with a drawer in one end and with a tray, c, for containing blankets, etc. [illustration: hogins improved table.] the convenience and practicability of this table for general laundry use, will be apparent without further explanation. the board, b, when drawn out will be used for ironing skirts, shirts, and other garments requiring a board of this character, and when the table is closed together and fastened by the hooks, it may be used in ironing larger articles. when closed it presents the appearance of an ordinary table and may be used as such. further information may be obtained by addressing the inventor as above. * * * * * a novel engine regulator. the accompanying engraving represents two different styles of regulator, invented by mr. stenberg, in which the effect of centrifugal force is utilized. in a vessel, a, of parabolic shape is placed a disk, c, which floats on glycerine contained by the vessel, and is attached to the walls of the vessel by an annular membrane, so that it may rise and fall in a vertical direction as the glycerine is carried with more or less force toward the edge of the vessel by centrifugal action. the inner surface of the vessel, a, is provided with radial grooves, by which the rotary motion of the vessel is communicated to the glycerine. to the center of the disk, c, is attached a vertical rod, which extends downward through the hollow shaft and is connected with governor valve. an increase of speed throws the glycerine toward the periphery of the valve, and, raising the disk, c, closes the steam valve; a diminution of speed permits the glycerine to fall back, when the disk descends and the valve opens. [illustration: stenberg regulator.] the disk, c, has a small aperture for the admission and escape of air, and the apparatus is adjusted by pouring lead into the groove in the disk. the regulator shown in fig. operates upon the same principle, but it is adjusted by means of a spring. this apparatus is manufactured by blancke bros., magdeburg.--_musée de l'industrie._ * * * * * a strange people. botel tobago is an island in the south seas which has lately been visited by a party of united states naval officers. they were surveying a rock east of the south cape of formosa, and called at this island. they found a curious race of malay stock. these aborigines did not know what money was good for. nor had they ever used tobacco or rum. they gave the officers goats and pigs for tin pots and brass buttons, and hung around the vessel all day in their canoes waiting for a chance to dive for something which might be thrown overboard. they wore clouts only, ate taro and yams, and had axes, spears, and knives made of common iron. their canoes were made without nails, and were ornamented with geometrical lines. they wore the beards of goats and small shells as ornaments. such is the account of these strange people given by dr. siegfried, in a letter read at the last meeting of the philadelphia academy of natural sciences. * * * * * remedy for the new carpet beetle. noticing a statement made by mr. j. a. lintner, to the effect that the persian insect powder would probably prove unavailing as a remedy against the ravages of the new carpet beetle (_anthrenus_), w. l. carpenter, of the u.s.a., was led to institute some experiments with this well known insecticide, the results of which he communicates to the current number of the _naturalist_. a small quantity of the powder was introduced, on the point of a penknife, under a tumbler beneath which various insects were consecutively confined. the movements of the insects brought them in contact with the poison, which readily adhered to their body; in endeavoring to remove it from their appendages a few particles would be carried to the mouth and thence to the stomach, with fatal effect. the results were briefly thus: a honey bee became helpless in minutes; a mad wasp in minutes; a small ant in minutes; a large butterfly resisted the effects for over an hour, and apparently recovered, but died the next day; a house-fly became helpless in minutes; a mosquito in ; and a flea in minutes. in experimenting on beetles, an insect was secured as nearly the size of the carpet beetle as could be found. it was easily affected, and became helpless in minutes. in these, and experiments with various other insects, the scent from the powder did not produce any bad effect on those subjected to its odor where actual contact was not possible; but when carried to the mandibles the effect was to produce complete paralysis of the motor nerves. the experiments prove that all insects having open mouth parts are peculiarly susceptible to this popular insecticide. as a result, the writer does not hesitate to recommend the powder to housekeepers as an infallible agent in destroying the carpet beetle and preventing its ravages. the persian insect powder liberally sprinkled upon the floor before putting down a carpet, and afterward freely placed around the edges, and never swept away, will suffice to preserve a large sized carpet. no ill effects from its use need be feared by the householder, since the drug is poisonous to no kinds of animals except insects. * * * * * banana flour. the banana has recently found a new use in venezuela. it has the property of keeping the soil moist round it, in a country where sometimes no rain falls for months; so it has been employed to give freshness, as well as shade, to the coffee plant, whose cultivation has been greatly extended (venezuela produced , , kilogrammes of coffee in ). the venezuelans can consume but little of the banana fruit thus furnished, so that attention is being given to increasing its value as an export. at the paris exhibition were samples of banana flour (got by drying and pulverizing the fruit before maturity) and brandy (from the ripe fruit) the flour has been analyzed by mm. marcano and muntz. it contains . per cent of starch, and only . of azotized matter. * * * * * new stencil pen. the accompanying engraving shows new form of stencil pen invented by mr. j. w. brickenridge, of la fayette, ind. in fig. the entire apparatus is shown in perspective; fig. is a longitudinal section of the pen; and fig. is a vertical section of a portion of the driving apparatus. in this instrument compressed air is used as a motive force for driving the perforating needle. the inverted cup, shown in detail in fig. , has its mouth closed with a flexible diaphragm, which is vibrated rapidly by a pitman having a convex end attached by its center to the middle of the diaphragm. the pitman is reciprocated by a simple treadle motion, which will be readily understood by reference to fig. . [illustration: brickenridge's pneumatic stencil pen.] the cup has a small aperture covered by a valve to admit of the entrance of air when the diaphragm is drawn down. the pen, shown in detail in fig. , has a cup and flexible diaphragm similar to the one already described. the diaphragm rests upon the enlarged end of a bar which carries at its lower end a perforating needle. the pen is connected with the driving mechanism by a flexible tube. the needle bar is pressed lightly against the diaphragm by a spiral spring. when the treadle motion is operated the impelling diaphragm is rapidly vibrated, and through the medium of the air contained in the flexible tube it communicates motion to the pen diaphragm and consequently to the needle bar and needle. if, while the needle is reciprocated in this way, the pen is moved over the surface of the paper, a line of fine perforations will be made. with this instrument stencils may be made for making multiplied copies of maps, drawings, and manuscripts. * * * * * origin and progress of ocean telegraphy. at the celebration in this city of the twenty-fifth anniversary of the formation of the company for laying the first atlantic cable, monday, march , the projector of the enterprise, mr. cyrus w. field, spoke as follows: neighbors and friends: twenty-five years ago this evening, in this house, in this room, and on this table, and at this very hour, was signed the agreement to form the new york, newfoundland and london telegraph company--the first company ever formed to lay an ocean cable. it was signed by five persons, four of whom--peter cooper, moses taylor, marshall o. roberts, and myself--are here to-night. the fifth, mr. chandler white, died two years after, and his place was taken by mr. wilson g. hunt, who is also present. of my associates, it is to be said to their honor--as might have been expected from men of their high position and character--that they stood by the undertaking manfully for twelve long years, through discouragements such as nobody knows but themselves. those who applaud our success know little through what struggles it was obtained. one disappointment followed another, till "hope deferred made the heart sick." we had little help from outside, for few had any faith in our enterprise. but not a man deserted the ship: all stood by it to the end. my brother dudley is also here, who, as the counsel of the company, was present at the signing of the agreement, and went with mr. white and myself the week after to newfoundland, to obtain the charter, and was our legal adviser through those anxious and troubled years, when success seemed very doubtful. at st. john's the first man to give us a hearty welcome, and who aided us in obtaining our charter, was mr. edward m. archibald, then prime minister of newfoundland, and now for more than twenty years the honored representative of her majesty's government at this port, who is also here to-night. it is a matter for grateful acknowledgment that we were spared to see accomplished the work that we began; and that we meet now, at the end of a quarter of a century, to look with wonder at what has been wrought since in other parts of the world. our little company came into existence only a few weeks before the western union telegraph company, which is entitled to share in our congratulations, and has kindly brought a connecting wire into this room, by which we can this evening communicate with every town and village from the atlantic to the pacific; and by our sea cables, with europe, asia, africa, australia, new zealand, the west indies, and south america. while our small circle has been broken by death but once, very different has it been with the atlantic telegraph company, which was formed in london in , to extend our line across the ocean. at its beginning there were eighteen english and twelve american directors, thirty in all, of whom twenty-nine have either died or retired from the board. i alone still remain one of the directors. many of the great men of science on both sides of the atlantic, who inspired us by their knowledge and their enthusiasm, have passed away. we have lost bache, whose coast survey mapped out the whole line of the american shores; and maury, who first taught us to find a path through the depths of the seas; and berryman, who sounded across the atlantic; and morse; and last, but not least, henry. across the water we miss some who did as much as any men in their generation to make the name of england great--faraday and wheatstone, stephenson and brunel--all of whom gave us freely of their invaluable counsel, refusing all compensation, because of the interest which they felt in the solution of a great problem of science and engineering skill. it is a proud satisfaction to remember that while the two governments aided us so generously with their ships, making surveys of the ocean, and even carrying our cables in the first expeditions, such men as these gave their support to an enterprise which was to unite the two countries, and in the end to bring the whole world together. others there are, among the living and the dead, to whom we are under great obligations. but i cannot repeat the long roll of illustrious names. yet i must pay a passing tribute to one who was my friend, as he was the steadfast friend of my country--richard cobden. he was one of the first to look forward with the eye of faith to what has since come to pass. as long ago as he had a sort of prophet's dream that the ocean might yet be crossed, and advised prince albert to devote the profits of the great london exhibition of that year to an attempt thus to unite england with america. he did not live to see his dream fulfilled. but though men die, their works, their discoveries, and their inventions live. from that small beginning under this roof, arose an art till then scarcely known, that of telegraphing through the depths of the sea. twenty-five years ago there was not an ocean cable in the world. a few short lines had been laid across the channel from england to the continent, but all were in shallow water. even science hardly dared to conceive of the possibility of sending human intelligence through the abysses of the ocean. but when we struck out to cross the atlantic, we had to lay a cable over , miles long, in water over miles deep. that great success gave an immense impulse to submarine telegraphy then in its infancy, but which has since grown till it has stretched out its fingers tipped with fire into all the waters of the globe. "its lines have gone into all the earth, and its words to the ends of the world." to-day there are over , miles of cable, crossing the seas and the oceans. and, as if it were not enough to have messages sent with the speed of lightning, they must be sent in opposite directions at the same moment. i have just received a telegram from valentia, ireland, which reads, "this anniversary witnesses duplex working across the atlantic as an accomplished fact"--by which the capacity of all our ocean cables is doubled. who can measure the effect of this swift intelligence passing to and fro? already it regulates the markets of the world. but better still is the new relation into which it brings the different kindreds of mankind. nations are made enemies by their ignorance of each other. a better acquaintance leads to a better understanding; the sense of nearness, the relation of neighborhood, awakens the feeling of brotherhood. is it not a sign that a better age is coming, when along the ocean beds strewn with the wrecks of war, now glide the messages of peace? one thing only remains which i still hope to be spared to see, and in which to take a part, the laying of a cable from san francisco to the sandwich islands--for which i have received this very day a concession from king kalakaua, by his minister, who is here to night--and from thence to japan, by which the island groups of the pacific may be brought into communication with the continents on either side--asia and america--thus completing the circuit of the globe. but life is passing, and perhaps that is to be left to other hands. many of our old companions have fallen, and we must soon give place to our successors. but though we shall pass away, it is a satisfaction to have been able to do something that shall remain when we are gone. if in what i have done to advance this enterprise, i have done something for the honor of my country and the good of the world, i am devoutly grateful to my creator. this has been the great ambition of my life, and is the chief inheritance which i leave to my children. * * * * * correspondence. * * * * * the gary motor. _to the editor of the scientific american:_ in your article on the "gary motor," issue of march , page , you say: "there is no neutral line in the sense that polarity changes when mr. gary moves his piece of sheet iron with its attached shingle nail across the pole or near the pole of a magnet." "the most delicate instruments fail to detect such a change of polarity," etc. mr. gary's claim of a neutral line is of course absurd, but you are wrong in saying that the polarity does not change under the conditions described in the _harper's monthly_ article. mr. gary is perfectly correct in claiming a change of polarity in that experiment, although his other claim of deriving from this change of polarity a continuous motion without consuming energy are manifestly absurd. [illustration: gary motor a.] [illustration: gary motor b.] the change of polarity is easily explained. if a bar of soft iron, whose length is two or three times the distance between the poles of the horseshoe magnet, be placed in front of the latter as in the sketch, and at some distance, poles will be induced, as shown by the letters n s. now let the bar approach the magnet. when within a short distance consequent points will be formed and the polarity at the ends will be reversed, the bar having four poles, as in the second sketch. the bar of soft iron must have certain dimensions depending on the size and power of the horseshoe magnet. by using a powerful electro-magnet in place of a permanent one, a soft iron bar of considerable size may be used, and the change of polarity exhibited by showing the repulsion in one case for the south pole and in the other for the north pole of a heavy permanent magnet. when in the proper position a very small movement of the soft iron bar is sufficient to produce the change. wm. a. anthony. cornell university, ithaca, n. y., march , . * * * * * gary's neutral line. _to the editor of the scientific american:_ i have just read the article in the issue of march , on the gary motor, and cannot refrain from offering a suggestion on the subject. when i read the article referred to in _harper's_, i formed the same opinion of the so-called invention that the writer in the scientific american has expressed, and, in the main, such is my opinion still. i, however, tried the experiment by which gary claims to prove the existence of his neutral line, and soon found the same explanation that the writer in the american has given. i then, curiously enough, modified the experiment in precisely the manner he suggests, placing the magnet in a vertical position, and using first a piece of sheet iron and then an iron wire under it. this was before seeing the article in the scientific american. my experiment is well illustrated by the writer's diagram, except that the nail should be at the end of the iron wire, where its polarity is of course most strongly marked. but the result is not as he states it. for, as the wire is brought up toward the magnet, the nail drops off before the wire touches the magnet. when the sheet iron is used, the point at which the nail drops off is farther from the magnet than in the case of the wire, and when it is brought nearer it will again pick up the nail, which then continues to cling until the iron touches the magnet and afterwards. thus the existence of a line in which the soft iron, or induced magnet, does not attract the nail, and above and below which it does attract it, is demonstrated. that the polarity of the induced magnet is reversed when it crosses this line may be demonstrated as follows: when it is held beyond (or below) this line (fig. ), the negative pole of the permanent magnet, the positive being kept at a distance, may be made to approach the iron and touch it, without causing the nail to drop. (fig. .) but when contact occurs, the whole of the iron must possess the polarity of that part of the magnet which it touches, namely, negative. hence in the position indicated in fig. , the polarity of the induced magnet does not correspond with that of the permanent magnet, but is as indicated by the letters. on the other hand, if the positive pole alone be made to approach, the nail will drop; but when it is very near, or in contact, it again holds the nail, and the iron is now positive; and if the negative pole also be now brought into contact, the polarity of the soft iron will correspond with that of the magnet, as shown in fig. . [illustration: gary's neutral line a.] [illustration: gary's neutral line b.] [illustration: gary's neutral line c.] these experiments should be performed with the soft iron under both poles of the magnet, and the ends of the former should extend somewhat beyond the poles of the latter, or the nail is liable to jump to the magnet as the "neutral" line is crossed. the position of the letters in fig. , of the previous article, represents the polarity of the induced magnet to be the same as that of the permanent, which is true only within (or above) the line described; and this, together with his statement that no such line can be discovered, appears to indicate that the writer relied upon his knowledge of the laws of magnetism to state what would be the result, without testing it experimentally. it is probable that this reversal of polarity is susceptible of explanation by the known laws of magnetic currents, but if it has hitherto escaped observation, its discovery is certainly deserving of notice, and may lead to valuable results. of the fact, any one may easily convince himself by the simple experiments above described. g. h. felton, m.d. haverhill, mass., february , . * * * * * pneumatic clocks. _to the editor of the scientific american:_ in the description of the pneumatic clock, copied from _la nature_, and published in your journal of date st of march, the invention is credited to me. such is not the case. by an arrangement between mr. wenzel, mr. brandon of paris, and myself, patents have been obtained in france, england, etc., for the clock, and issued in my name; but the honor of the invention belongs exclusively to hermann j. wenzel, of san francisco. yours faithfully, e. j. muybridge. san francisco, cal., february , . * * * * * the ice cave of decorah, iowa. _to the editor of the scientific american:_ some years ago i visited the "ice cave" of decorah, winneshiek county, iowa, and having since been unable to receive any explanation of the wonderful phenomenon exhibited by it, i write, hoping that you or some correspondent may explain the paradox. the thriving town of decorah lies in a romantic valley of the upper iowa river, and the cave is almost within its corporate limits. following the left bank of the stream, one soon reaches the vicinity, and with a hard scramble through a loose shale, up the side of a precipitous hill, forming the immediate bank of the river, the entrance is gained--an opening feet wide and feet high. these dimensions generally describe the cave's section. from the entrance the course is a steep decline--seldom less than °. at times the ceiling is so low that progress on hands and knees is necessary. about feet from the entrance the "ice chamber" is reached. at this spot the cave widens into a well proportioned room, by feet. the floor is solid ice of unknown thickness, and on the right hand wall of the room a curtain of ice drops to the floor, from a crevice extending horizontally in the rock at the height of one's eyes. close examination discovers the water oozing from this crevice, and as it finds its way down the side it freezes in the low temperature of the chamber. singularly this one crevice, and that no wider than a knife edge, furnishes this, nature's ice house, with the necessary water. it was a hot day in august, the thermometer marking ° in the shade when the visit was made, and comparatively the cold was intense. in common with all visitors, we detached some large pieces of ice and with them hurriedly departed, glad to regain the warmth of the outside world. the most remarkable fact in connection with this wonder is that the water only freezes in the summer. as the cold of actual winter comes on the ice of the cave gradually melts, and when the river below is frozen by the fierce cold of northern iowa, the ice has disappeared and a muddy slush has taken the place of the frigid floor. i would add that the ice chamber forms the terminus of the cave. beyond a shallow crevice in the crumbling rock forbids further advance. the rock formation of this region is the portland sandstone. why should the temperature of the ice chamber be such as to freeze the water trickling into it? and above all, why should the ice disappear with the cold of winter? mansfield, o. h. m. w. * * * * * the writing telegraph. on the evening of february , , the writing telegraph of mr. e. a. cowper, of london, was exhibited in operation before the society of telegraph engineers, in that city. it is a curious and remarkable invention. by its use the handwriting of the operator may be transmitted, but a double circuit, that is, two telegraph wires, are used. the operator moves with his hand an upright pointer or stylus, with which he writes the message on paper. the stylus has two arms connected with it, one of which arms, when the stylus makes an upward movement, causes a current to be sent over one wire, while the other arm causes a current to pass over the other wire when the stylus is moved laterally. these two motions are, at the receiving end of the line, made to operate on the needles of galvanometers, and the latter are by silk threads combined or connected with a delicately suspended ink tube, from which a minute stream of ink falls upon the strip of paper below it; the arrangement being such that the combined motions of the galvanometers so move the ink pen as to make it correspond to the motion of the stylus at the sending end. the apparatus is said to work very well, and it is expected that it will form a useful adjunct to the art of telegraphy. we present herewith a facsimile of writing done by this new instrument, which has been worked with success over a line of forty miles length. it is hardly probable that it can compete in rapidity with some of the telegraph instruments now in use; but for many purposes it is likely to become important, while in point of ingenuity it is certainly a great achievement, and the author is deserving of the highest credit. [illustration: writing telegraph.] * * * * * a rare geological specimen. rev. r. m. luther, while absent in attendance upon the missionary convention, held in addison, vt., obtained through the kindness of the rev. mr. nott a rare and curious geological specimen from the shores of lake champlain. it is a slab of limestone, about eleven inches long by six inches wide, which seems to be composed almost entirely of fossils. there is not half an inch square of the surface which does not show a fossil. there are many varieties, some of which have not been identified, but among those which have been are many remains of the trinucleus conceniricus, some specimens of petraia, fragments of the orthis, a number of discinæ, several well preserved specimens of leptenæ, and impressions of lingula. the latter is the only shell which has existed from the first dawn of life until the present time without change. the specimens of existing lingula are precisely similar to those found in the earliest geological formations. there are also in the slab several rare specimens of seaweed, remains of which are seldom found at so early an age in the geological history of the world. the slab belongs to the lower silurian formation, the first in which organic remains are found. it is probably from the trenton epoch of that age. if geologists can be trusted, at the time the little animals, whose remains are thus preserved, were living, the only part of this continent which had appeared above the primeval ocean was a strip of land along the present st. lawrence river and the northern shores of the great lakes, with a promontory reaching out toward the adirondacks, and a few islands along what is now the atlantic coast line.--_bennington (vt.) banner._ * * * * * cowper's writing telegraph. the most recent of the brilliant series of telegraphic marvels which has from time to time, and especially of late, engaged the attention of the world, is the "telegraphic pen" of mr. e. a. cowper, the well known engineer of great george street, westminster. this ingenious apparatus, which constitutes the first real telegraph, was publicly shown by its inventor at the meeting of the society of telegraph engineers on wednesday, february . there had been no lack of copying telegraphs hitherto. we have bakewell's, casselli's, meyer's, and d'arlincourt's, so recently tried at our general post office by mr. preece. all of these instruments telegraph an almost perfect copy of the writing or sketch submitted to them by means of synchronous mechanism. but the process is necessarily complex and slow; whereas by the new device a person may take the writing pencil in his hand, and himself transmit his message in the act of writing it. the principle which guided mr. cowper to a solution of the problem which he has successfully overcome, is the well known mathematical fact that the position of any point in a curve can be determined by its distance from two rectangular co-ordinates. it follows, then, that every position of the point of a pencil, stylus, or pen, as it forms a letter, can be determined by its distance from two fixed lines, say the adjacent edges of the paper. moreover it is obvious that if these distances could be transmitted by telegraph and recombined so as to give a resultant motion to a duplicate pen, a duplicate copy of the original writing would be produced. but inasmuch as the writing stylus moves continuously over the paper, the process of transmission would require to be a continuous one; that is to say, the current traversing the telegraph line, and conveying the distances in question (or what comes to the same thing, the up and down, and direct sidelong ranges of the stylus) would require to vary continuously in accordance with the range to be transmitted. mr. cowper effects this by employing two separate telegraphic circuits, each with its own wire, battery, sending, and receiving apparatus. one of these circuits is made to transmit the up and down component writing of the pencil's motion, while the other simultaneously transmits its sidelong component. at the receiving station these two components are then recomposed by a pantograph arrangement of taut cords, or levers, and the resultant motion is communicated to the duplicate pen at that place. the plan adopted by mr. cowper to transmit each continuously varying component is to cause the resistance of the circuit to vary very closely with the component in question. fig. shows how the apparatus is theoretically arranged for this purpose. p is the writing style, which is held in the writer's hand in the ordinary way, while he shapes the letters one by one on paper pulled uniformly underneath by means of clockwork. to p are attached, at right angles, two arms, a a, one for each circuit; but as it is only necessary to consider one of the circuits, say that sending up and down motions, we will confine our attention for the present to the arm, a. one pole of the sending battery, b, is connected to the arm, a, the other pole being connected to earth. now the arm, a, is fitted with a sliding contact at its free extremity, and as the pencil, p, is moved in writing, a slides lengthwise across the edges of a series of thin metal contact plates, c, insulated from each other by paraffined paper. between each pair of these plates there is a resistance coil, c, and the last of these is connected through the last plate to the line, l. it will be seen that as a slides outward across the plates the current from the battery has to pass through fewer coils, since a short-circuits a number of coils proportional to its motion. but the fewer of these coils in circuit the stronger will be the current in the line; so that the extent of the motion of the arm, a, in the direction of its length, that is to say, the direct component of the motion of the pencil along the line of the arm, a, is attended by a corresponding change in the current traversing the line. if the pencil makes a long up and down stroke there will be a strong current in the line, if a short one there will be a weak current, and so on. a precisely similar arrangement is used to transmit the sidelong motion of the pencil along the line, l. [illustration: fig. .] the current from the line, l, flows at the receiving station through a powerful galvanometer, g, to earth. the galvanometer has a stout needle, one tip of which is connected to a duplicate pen, p, by a thread, t, which is kept taut by a second thread stretched by a spring, s'. the current from the line, l', flows through a similar galvanometer, g', to earth. the needle of g' is also connected to the pen, p, by a taut thread, t', stretched by means of the spring, s. now, since the needle of each of these galvanometers deflects in proportion to the strength of the current flowing through its coil, the points of these two needles keep moving with the varying currents. but since these currents vary the motions of the sending pen, the receiving pen controlled by the united movements of the needles will trace out a close copy of the original writing. we give on another page a facsimile of a sentence written by mr. cowper's telegraph. [illustration: the cowper writing telegraph.] the receiving pen is a fine glass siphon, drawing off aniline ink from a small glass holder. there are thirty-two coils, c, in each circuit, with a corresponding number of contact plates, c, so as to get accuracy of working. a few daniell's cells are sufficient to operate the apparatus, and writing has been already sent successfully over a line miles in length. the writing may be received either of the same size or larger or smaller than the original, as the case may be. at present the writing must not be too hurried, that is, unless the characters are bold and well formed; but further improvement will, of course, quicken the working of the apparatus. the engravings, figs. to , illustrate the actual apparatus. fig. is a plan of the sending instrument, with the writing pencil, a, the traveling paper, b, the light connecting rods or arms, d (which correspond to a in the theoretical diagram above), the series of metal contact plates over which these arms slide, the resistance coils connected to these plates, and the battery and line wires. it will be seen that each arm, d, is connected to its particular battery, and each set of contact plates to its particular line. fig. is an elevation of the sending instrument, in which a is the pencil as before, c c the contact plates over which the arms, d d, slide, f f the coils, and b the traveling slip of paper. fig. is a plan of the receiving instrument, in which h h are the light pivoted needles surrounded by coils of fine insulated copper wires, i i, and controlled in their zero position by the electro-magnets, j j j j, placed underneath, the whole forming a pair of galvanoscopes or current detecters, one for each line. it will be understood that the varying currents from the lines are allowed to flow through the coils, i i, so as to deflect the needles, and that the deflections of the needles follow, so to speak, the variations of the currents. the electro-magnets are magnetized by a local battery; permanent magnets might, however, take their place with a gain in simplicity. now the writing pen, k, is connected to the nearest tip of the needle, h, of each galvanoscope by threads, n n, which are kept taut by the fibers, o_{ } o_{ } o_{ }, the springs, o, and the pins, o_{ }. in this way the motions of the needles are recombined in the motion of the duplicate pen upon the paper, p. fig. is an elevation of the receiving instrument, in which i i are the coils as before, j j j j the controlling electro-magnets, k is the writing siphon dipping with its short leg into the ink well, m, and l is the bridge from which the writing siphon is suspended by means of a thread and spring. the long leg of the siphon reaches down to the surface of the paper, p, which is pulled along beneath it in contact with the film of ink filling the point of the tube. when the siphon is at rest its point marks a zero line along the middle of the paper, but when the receiver is working, the siphon point forms each letter of the message upon the paper as it passes.--_engineering._ * * * * * aluminum. the splendid exhibit of the french aluminum manufacturers at the late exhibition has again called attention to that metal, which is so admirably adapted to many purposes on account of its great lightness and its stability under the influence of the atmosphere. while aluminum industry has heretofore been thought to be confined to france solely, we are now told by mr. c. bambery, in the annual report of the society of berlin instrument makers, that for some years past aluminum has been extensively manufactured in berlin. three firms especially (stückradt, häcke, and schultze) are engaged in this branch of industry. the articles manufactured principally are nautical instruments, as sextants, compasses, etc. the german navy is supplied throughout with aluminum instruments. as a proof of the superiority of german aluminum, it may here be mentioned that the normal sets of weights and balances used by the international commission for the regulation of weights and measures, which lately was in session at paris, were obtained from stückradt, in berlin, and not from any of the firms at paris, the reputed seat of aluminum industry. aluminum is, in berlin, generally used pure, and cast pieces only are composed of aluminum containing about per cent of silver. nevertheless the use of aluminum will remain limited, even in case the cost of manufacturing it could be materially reduced, until some method shall have been discovered by which aluminum may be soldered. this difficulty has, in spite of all efforts, not yet been overcome, and for some purposes, to which the metal would otherwise be well adapted, it remains so far unavailable. here then is a chance for some ingenious mind. * * * * * an improved door bolt. the accompanying engraving represents, in perspective and in section, an improved door bolt, recently patented by mr. thomas hoesly, of new glaras, wis. the principal features of this bolt will be understood by reference to the engraving. on the plate or body are cast two loops or guides for the bolt, and the plate is slotted under the bolt, and a lug projects into the slot and bears against a spring contained by a small casing riveted to the back of the plate. the end of the bolt is beveled, and its operation is similar to that of the ordinary door latch. two handles are provided, one of which is of sufficient length to reach through the door, and a pawl or dog accompanies the bolt, which may be attached to the door with a single screw, and is to be used in locking the door. the bolt is very simple and strong, suitable for shops, out-buildings such as barns, stables, etc., and some of the doors of dwellings. [illustration: hoesly's door bolt.] further information may be obtained by addressing the inventor, as above. * * * * * chimney flues. messrs. w. h. jackson & co., of this city, whose long experience in treating refractory flues gives weight to their opinion, communicate to the _american architect_ the following useful information: to secure a good draught the chimney should be of sufficient size, should be carried up above surrounding objects, should be as straight as possible throughout its length, and should be as smooth as possible inside, to avoid friction. as a draught is caused by unequal temperatures, the chimney should be so arranged as to avoid a rapid radiation of heat. if in an exterior wall there should be at least inches of brickwork between the flue and the exterior surface. for country houses it is much better to have the chimneys run up through the interior, as the flue is more easily kept warm, and the heat that is radiated helps to warm the house. the most frequent cause of a "smoky chimney" is the insufficient size of the flue for the grate or fireplace connected therewith. the flue should not be less than one eighth the capacity of the square of the width and height of the grate or fireplace. that is, if the grate has a front opening inches wide and inches high, the flue should be in. × in.; or, with an opening inches wide and inches high, the flue should be in. × in.; and, to get the best result, the opening into the flue from the grate or fireplace should be of a less number of square inches than the square of the flue, and never larger, as no more air should be admitted at the inlet than can be carried through the flue. where there is more than one inlet to the same flue, the sum of all the inlets should not more than equal the size of the flue. a number of stoves may be connected with the same flue, one above another, if this rule is observed. a square flue is better than a narrow one, as in two flues containing the same number of square inches the square flue would have the smallest amount of wall surface, and consequently less friction for the ascending currents, and less absorption of heat by the walls. chimneys should be closely built, having no cracks nor openings through which external air may be drawn to weaken the draught. if they could be made throughout their length as impervious to air as a tube of glass, with interior surface as smooth, one cause of smoky chimneys would be removed. a downward current of air is frequently caused by some contiguous object higher than the chimney, against which the wind strikes. this higher object may sometimes be quite a distance from the chimney, and still affect it badly. a good chimney top constructed to prevent a down draught will remedy this difficulty. each grate or fireplace should have a flue to itself. under very favorable conditions, two grates or fireplaces might be connected with the same flue, but it is not a good plan. we have known grates and fireplaces connected with two flues, where they have been built under a window for instance, and, owing to there being insufficient room for a flue of suitable size, a flue has been run up on each side of the window. this is a very bad plan, and never can work well; it requires too much heat to warm both flues, and if the room in which the grate or fireplace is situated should be pretty close, so that there was no other entrance for air, there is danger that it would circulate down one flue and up the other, forcing smoke out of the fireplace into the room. * * * * * improved furnace for burning garbage. the refuse matter and garbage of large cities is in the main composed of animal and vegetable offal of the kitchens; of the sweepings of warehouses, manufactories, saloons, groceries, public and private houses; of straw, sawdust, old bedding, tobacco stems, ashes, old boots, shoes, tin cans, bottles, rags, and feathers; dead cats, dogs, and other small animals; of the dust and sweepings of the streets, the condemned fruit, vegetables, meat, and fish of the markets, all of which compose a mass of the most obnoxious and unhealthy matter that can be deposited near human habitations. the inventor of the furnace shown in the accompanying engravings aims to produce a change of form and of chemical nature and a great reduction in bulk of all such refuse and garbage within the limits of the city where it accumulates, without screening, separating, preparing, or mixing, without the expense of using other fuel, without any offensive odors being generated in the operation, and to produce an entirely unobjectionable residuum or product that may be made useful. [illustration: fig. .--foote's furnace for burning garbage.] as a rule organic matter largely preponderates in the refuse, being as high in some instances as per cent. there is always more than enough to generate sufficient heat to fuse the earthy or inorganic portion, which is mainly composed of sand, clay, and the alkalies from the coal and vegetable ashes, etc. by producing a high degree of heat in the combustion of the organic portion of the refuse with a forced blast or forced draught, the non-combustible elements are fused, and form a vitreous slag, which is entirely inodorous and unobjectionable, and which may be utilized for many purposes. the upper section or cone of the consuming furnace is built of boiler iron, and lined with fire brick resting upon an iron plate, which is supported by iron columns. the hearth is made of fire brick, and is in the form of an inverted cone, being smaller at the bottom and larger at the top, as shown in fig. . the sides of the hearth are perforated near the bottom with arches for the tuyeres or blast pipes, and also in front for the special blast pipe and the tapping hole. the top of the furnace is closed with an iron plate, provided with a circular opening, through which the hopper enters the top of the furnace. at the left in the larger engraving is seen an elevator, operated by a steam engine, for conveying the garbage and refuse to a platform, whence it is projected into the furnace by an inclined plane or chute. gas or smoke conductors convey the gas from the top of the furnace to the furnace of the boiler and to the heating oven, where it is used in heating air, which is conveyed through the iron pipes passing through the heating oven into a wind box, from which it enters the furnace at several points near the bottom by means of the tuyere pipes. [illustration: section of furnace.] the consumption of the garbage is effected near the bottom of the furnace, where the air is forced in, and is continued as long as the blast is applied, and while burning at the base it is continually sinking down at the top, so that it is necessary to keep filling all the time. the odoriferous gases and the hot products of such combustion are forced upward through the superimposed mass, and escape to the fires of the boiler and heating oven, and, being largely composed of carbonic oxide and the hydrocarbon gases distilled from the animal and vegetable offal of the garbage, are thoroughly consumed; and it is said that by this means not only are all the offensive odors destroyed, but the heat generated is utilized for making steam and heating the air used for blast. the refuse in its descent through the high furnace is exposed to the drying action of the hot gases of distillation and the hot products of combustion, its temperature increasing in its descent the nearer it approaches the tuyeres, and becomes completely desiccated and combustible when it reaches the blast. the high heat in this way obtained by the combustion of the organic portion melts all of the inorganic portion, forming a vitreous slag or glass, which may be allowed to run continuously, or by closing the tap may be allowed to accumulate, and can be drawn off at intervals. if there is an adequate supply of clay and sand in the refuse to combine with the ashes, the slag will run hot and free. the combination of silex or alumina and an alkali in proper portions always yields a fusible, easy-running compound. the molten slag, as it runs from the furnace, may be discharged into tanks of cold water, which will pulverize or granulate it, making it like fine sand, or as it pours over a runner, through which it flows, if struck with a forcible air or steam blast it will be spun into fine thread-like wool. the furnace once lighted and started may be kept running day and night continuously for days, months, or years, if desired; but if it becomes necessary to stop at any time, the tuyere pipes may be removed and the holes all stopped with clay, so as to entirely shut off the supply of air, and it will then hold in fire for many days, and will be in readiness to start again at any time the pipes are replaced and the blast turned on. this furnace is the invention of mr. henry r. foote, of stamford, conn. * * * * * an ancient greek vase. the vase shown in the accompanying engravings must not be classed with ordinary ceramic ware, as it is a veritable work of art. it is the celebrated cup of arcesilaus, which is preserved in the collection of the library of richelieu street after having figured in the durand museum. it was found at vulsei, in etruria. it was made by a potter of cyrene, the capital of cyrenaica, founded by greeks from the island of thera. it is remarkable that cyrene, removed from the center of grecian manufacture, should possess a manufactory of painted vases from which have come so many works of art. the traveler, paul lucas, discovered in the necropolis of cyrene, in , many antique vases, both in the tombs and in the soil. one of them is still preserved in the museum at leyden. the arcesilaus, who is represented on this vase, is not the celebrated skeptical philosopher of that name; it is arcesilaus, king of cyrenaica, who was sung by pindar, and who was vanquished in the pythian games under the th olympiad ( years b.c.). the height of this vase is centimeters, its diameter centimeters. the paste is very fine, of a pale red. it is entirely coated with a black groundwork, which has been generally re-covered with a yellowish white clay, baked on. according to m. brongniart, this piece has been subjected to the baking process at least two or three times, thus indicating that the ceramic art had made considerable progress in cyrene even at that remote epoch. the following description of this vase is given in the catalogue of the durand museum: the king arcesilaus is seated under a pavilion upon the deck of a ship. his head is covered with a kind of hat with a large brim, and his hair hangs down upon his shoulders. he is clothed in a white tunic and embroidered cloak or mantle, and he carries a scepter in his left hand; under his seat is a leopard, and his right hand he holds toward a young man, who makes the same gesture, and he is weighing in a large scale assafoetida, which is being let down into the hold of the ship. we know that he deals with assafoetida because one of the personages (the one who lifts up his arm toward the beam of the scale) holds in his right hand something resembling that which is in the scale, and the greek word traced near it signifies "that which prepares _silphium_." assafoetida, the resinous matter of the silphium, is used largely by the greeks in the preparation of their food. the orientals to-day make frequent use of it and call it the delight of the gods; while in europe, because of its repulsive odor, it has long been designated as _stircus diaboli_. [illustration: fig. .--ancient greek vase.] [illustration: fig. .--top of greek vase.] * * * * * snow-raised bread. somebody thinks he has discovered that snow, when incorporated with dough, performs the same office as baking powder or yeast. "i have this morning for breakfast," says a writer in the _english mechanic_, "partaken of a snow-raised bread cake, made last evening as follows: the cake when baked weighed about three quarters of a pound. a large tablespoonful of fine, dry, clean snow was intimately stirred with a spoon into the dry flour, and to this was added a tablespoonful of caraways and a little butter and salt. then sufficient cold water was added to make the dough of the proper usual consistence (simply stirred with the spoon, not kneaded by the warm hands), and it was immediately put into a quick oven and baked three quarters of an hour. it turned out both light and palatable. the reason," adds the writer, "appears to be this: the light mass of interlaced snow crystals hold imprisoned a large quantity of condensed atmospheric air, which, when the snow is warmed by thawing very rapidly in the dough, expands enormously and acts the part of the carbonic acid gas in either baking powder or yeast. i take the precise action to be, then, not due in any way to the snow itself, but simply to the expansion of the fixed air lodged between the interstices of the snow crystals by application of heat. this theory, if carefully followed out, may perchance give a clew to a simple and perfectly innocuous method of raising bread and pastry." and stop the discussion as to whether alum in baking powders is deleterious to health or otherwise. * * * * * new agricultural inventions. an improved gate, invented by messrs. p. w. mckinley and george l. ellis, of ripley, o., is designed for general use. it is operated by cords and pulleys, and can be opened without dismounting from the horse. it is constructed so that it cannot sag, and is not liable to get out of order. an improved apparatus for pressing tobacco has been patented by mr. f. b. deane, of lynchburg, va. it consists mainly in the construction of a suspended jack, arranged to travel over a row of hogsheads, so that a single jack gives successively to each hogshead the desired pressure. an improved combined harrow and corn planter has been patented by mr. m. mcnitt, of hanover, kan. in this machine the opening, pulverizing, planting, and covering teeth are combined with a single frame. a machine, which is adapted to the thrashing and cleaning of peas and seeds, and for cleaning all kinds of grain, has been patented by mr. j. j. sweatt, of conyersville, tenn. mr. amos m. gooch, of farmington, w. va., has patented an improved corn planter, which drops the fertilizer simultaneously with the seed, and is provided with a device for pressing the soil around the seed, leaving over the seed a portion of loose earth. an improved machine for harvesting cotton has been patented by r. h. pirtle, of lowe's, ky. this machine carries two vertical cylinders armed with teeth or spurs, and two inclined endless belts provided with teeth. the teeth of the cylinders and the belts remove the cotton from the plants, and deliver it to a receptacle carried by the machine. messrs. julius fern and samuel bligh, of oneonta, n. y., have patented an improved power for churning and other purposes where little power is required. it consists in the combination of a drum and weight, a train of gearing, and a pallet wheel arranged to oscillate a balanced beam. an improvement in the class of feed cutters in which two or more knives work between parallel bars attached to the cutter box, has been patented by messrs. j. n. tatum and r. c. harvey, of danville, va. the improvement consists in arranging the knives so that one begins and finishes its cut in advance of the other. mr. william bradberry, of darrtown, o., has invented an improvement in reciprocating churns. the aim of this inventor is to utilize the resistance of the milk as a source of power. to accomplish this a peculiar combination of mechanism is required, which cannot be clearly described without an engraving. * * * * * reading and eyesight. m. javel, in a recent lecture, tries to answer the question, "why is reading a specially fatiguing exercise?" and also suggests some remedies for this fatigue. first, m. javel says reading requires an absolutely permanent application of eyesight, resulting in a permanent tension of the organ, which may be measured by the amount of fatigue or by the production of permanent myopy. secondly, books are printed in black on a white ground; the eye is thus in presence of the most absolute contrast which can be imagined. the third peculiarity lies in the arrangement of the characters in horizontal lines, over which we run our eyes. if we maintain during reading a perfect immobility of the book and the head, the printed lines are applied successively to the same parts of the retina, while the interspaces, more bright, also affect certain regions of the retina, always the same. there must result from this a fatigue analogous to that which we experience when we make experiments in "accidental images," and physicists will admit that there is nothing more disastrous for the sight than the prolonged contemplation of these images. lastly, and most important of all in m. javel's estimation, is the continual variation of the distance of the eye from the point of fixation on the book. a simple calculation demonstrates that the accommodation of the eye to the page undergoes a distinct variation in proportion as the eye passes from the beginning to the end of each line, and that this variation is all the greater in proportion to the nearness of the book to the eye and the length of the line. as to the rules which m. javel inculcates in order that the injurious effects of reading may be avoided, with reference to the permanent application of the eyes, he counsels to avoid excess, to take notes in reading, to stop in order to reflect or even to roll a cigarette; but not to go on reading for hours on end without stopping. as to the contrast between the white of the paper and the black of the characters, various experiments have been made in the introduction of colored papers. m. javel advises the adoption of a slightly yellow tint. but the nature of the yellow to be used is not a matter of indifference; he would desire a yellow resulting from the absence of the blue rays, analogous to that of paper made from a wood paste, and which is often mistakenly corrected by the addition of an ultramarine blue, which produces gray and not white. m. javel has been led to this conclusion both from practical observation and also theoretically from the relation which must exist between the two eyes and the colors of the spectrum. his third advice is to give preference to small volumes which can be held in the hand, which obviates the necessity of the book being kept fixed in one place, and the fatigue resulting from accidental images. lastly, m. javel advises the avoidance of too long lines, and therefore he prefers small volumes, and for the same reason those journals which are printed in narrow columns. of course every one knows that it is exceedingly injurious to read with insufficient light, or to use too small print, and other common rules. m. javel concludes by protesting against an invidious assertion which has recently been made "in a neighboring country," according to which the degree of civilization of a people is proportional to the number of the short sighted shown to exist by statistics; the extreme economy of light, the abuse of reading to the detriment of reflection and the observation of real facts, the employment of gothic characters and of a too broad column for books and journals, are the conditions which, m. javel believes, lead to myopy, especially if successive generations have been subjected to these injurious influences. * * * * * phosphorescence. m. nuesch records, in a recent number of the _journal de pharmacie_, some curious observations regarding luminous bacteria in fresh meat. some pork cutlets, he found, illuminated his kitchen so that he could read the time on his watch. the butcher who sent the meat told him the phosphorescence was first observed in a cellar, where he kept scraps for making sausages. by degrees all his meat became phosphorescent, and fresh meat from distant towns got into the same state. on scratching the surface or wiping it vigorously, the phosphorescence disappears for a time; and the butcher wiped carefully the meat he sent out. all parts of the animal, except the blood, acquired the phenomenon over their whole surface. the meat must be fresh; when it ceases to be so, the phosphorescence ceases, and _bacterium termo_ appear. none of the customers had been incommoded. it was remarked that if a small trace of the phosphorescent matter were put at any point on the flesh of cats, rabbits, etc., the phosphorescence gradually spread out from the center, and in three or four days covered the piece; it disappeared generally on the sixth or seventh day. cooked meat did not present the phenomenon but it could be had in a weak manner, from cooked albumen or potatoes. no other butcher's shop in the place was affected. the author is uncertain whether to attribute the complete disappearance of the phenomenon to the higher temperature of the season, or to phenic acid, or to fumigation with chlorine. * * * * * the charms of natural science. the earl of derby, in an address at the edinburgh university, said: "of the gains derivable from natural science i do not trust myself to speak; my personal knowledge is too limited, and the subject is too vast. but so much as this i can say--that those who have in them a real and deep love of scientific research, whatever their position in other respects, are so far at least among the happiest of mankind.... no passion is so absorbing, no labor is so assuredly its own reward (well that it is so, for other rewards are few); and they have the satisfaction of knowing that, while satisfying one of the deepest wants of their own natures, they are at the same time promoting in the most effectual manner the interests of mankind. scientific discovery has this advantage over almost every other form of successful human efforts, that its results are certain, that they are permanent, that whatever benefits grow out of them are world-wide. not many of us can hope to extend the range of knowledge in however minute a degree; but to know and to apply the knowledge that has been gained by others, to have an intelligent appreciation of what is going on around us, is in itself one of the highest and most enduring of pleasures." the vesuvius rail way.--the italian ministry of public works, in union with the ministry of finance and the prefecture of naples, has issued the concession for the construction of the vesuvius railway. the line will run along that part of the mountain which has been proved, after the experience of many years, to be the least exposed to the eruptions. the work is to be commenced immediately, and it is believed that it will come into use during the present year. a sufficient number of carriages are being built to convey persons during the day. the line is to be constructed upon an iron bridge, built after a patented system. * * * * * the pottery tree. among the various economic products of the vegetable kingdom, scarcely any hold a more important place than barks, whether for medicinal, manufacturing, or other purposes. the structure and formation of all barks are essentially very similar, being composed of cellular and fibrous tissue. the cell contents of these tissues, however, vary much in different plants; and, for this reason, we have fibrous or soft, woody, hard, and even stony barks. to explain everything which relates to the structure of bark would lead us into long details which our space will not permit. briefly stated, the bark of trees (considering, now, those of our own climate) consists of three layers. the outermost, called the "cortical," is formed of cellular tissue, and differs widely in consistency in different species; thus, in the cork oak, which furnishes man with one of his most useful commercial products, the cortical layer acquires extraordinary thickness. the middle layer, called the "cellular" or "green bark," is a cellular mass of a very different nature. the cells of which it is composed are polyhedral, thicker, and more loosely joined, and filled with sap and chlorophyl. the inner layer (next the wood), called the "liber," consists of fibers more or less long and tenacious. it is from the liber that our most valuable commercial fibers are obtained. in some plants the fibrous system prevails throughout the inner bark; but what we wish to refer to more particularly at present is a remarkable example of the harder and more silicious barks, and which is to be found in the "pottery tree" of para. this tree, known to the spaniards as _el caouta_, to the french as _bois de fer_, to the brazilians as _caraipe_, is the _moquilea utilis_ of botanists, and belongs to the natural order _ternstroeiaceæ_. it is very large, straight, and slender, reaching a height of feet before branching; its diameter is from to inches; and its wood is exceedingly hard from containing much flinty matter. although the wood of the tree is exceedingly sound and durable, the great value of the tree to the natives exists in the bark for a purpose which, to say the least, is a novel one in the application of barks--that of the manufacture of pottery. the indians employed in the manufacture of pottery from this material always keep a stock of it on hand in their huts for the purpose of drying and seasoning it, as it then burns more freely, and the ashes can be gathered with more ease than when fresh. in the process of manufacturing the pottery the ashes of the bark are powdered and mixed with the purest clay that can be obtained from the beds of the rivers; this kind being preferred, as it takes up a larger quantity of the ash, and thus produces a stronger kind of ware. though the proportions of ash and clay are varied at the will of the maker, and according to the quality of the bark, a superior kind of pottery is produced by a mixture of equal parts of fine clay and ashes. all sorts of vessels of small or large size for household or other purposes are made of this kind of ware, as are also vases or ornamental articles, many of which are painted and glazed. these articles are all very durable, and are able to stand almost any amount of heat; they are consequently much used by the natives for boiling eggs, heating milk, and indeed for culinary purposes generally. a brief glance at the structure of the bark will show how it comes to be so well adapted for this purpose. the bark seldom grows more than half an inch thick, and is covered with a skin or epidermis; when fresh, it cuts somewhat similar to a soft sandstone, but when dry, it is very brittle and flint like, and often difficult to break. on examination of a section under the microscope, all the cells of the different layers are seen to be more or less silicated, the silex forming in the cells when the bark is still very young. in the inner bark the flint is deposited in a very regular manner, the particles being straight and giving off branches at right angles; that of the porous cells of the bark, however, is very much contorted, and ramifies in all directions. in the best varieties of the tree, those growing in rich and dry soil, the silex can be readily detected by the naked eye; but to test the quality of the various kinds of bark, the natives burn it and then try its strength between their fingers; if it breaks easily it is considered of little value, but if it requires a mortar and pestle to break, its quality is pronounced good. from an analysis of this singular bark, that of old trees has been found to give . per cent of ash, and that of young . per cent. of the different layers of old bark, the outer gave . per cent, the middle . , and the inner . the wood of the tree, in comparison with the bark, is relatively poor in silex, the duramen of an old tree giving only . per cent of silex. * * * * * glass sponges. the natural history of sponges had, up to the middle of this century, been comparatively neglected. until , when lieberkuhn published his treatise on sponges, very little or nothing had been written on the subject. later, haeckel did much to determine their exact nature, and it is now universally admitted that sponges form one of the connecting links between the animal and the vegetable kingdom. sponges, generally considered, consist of fine porous tissue, covered, during life, with viscid, semi-liquid protoplasm, and are held in shape and strengthened by a more or less rigid skeleton, consisting chiefly of lime or silica. the tissue consists of a very fine network of threads, formed probably by gradual solidification of the threads of protoplasm. the inorganic skeleton is formed by larger and smaller crystals and crystalline threads. in the various families of sponges the quantity of inorganic matter varies greatly; some sponges are nearly devoid of an inorganic skeleton, while other families consist chiefly of lime or silica, the organic tissue being only rudimentarily developed. as observed in their natural state, sponges are apparently lifeless. when, however, a live sponge is placed in water containing some finely powdered pigment in suspension, it will be noticed that in regular, short intervals water is absorbed through the pores of the tissue and ejected again through larger openings, which are called "osculæ." following up these into the interior, we find them divided into numerous branches, the walls of which are, under the microscope, found to be covered with minute cells, fastened at one end only and oscillating continually. by means of these cells the sponge receives its nourishment. sponges with very rigid inorganic skeletons may be divided into two classes--calcareous and silicious--according to whether the skeleton is chiefly composed of lime or silica. our engravings represent two species of the latter kind, which are, on account of the peculiar appearance of their skeleton, called glass sponges. fig. represents the "sprinkling pot sponge," _eucleptella aspergillum_. it is generally found in very deep water throughout the pacific. specimens were found over fifty years ago, but, as they had to be brought up from depths between and fathoms, they remained very scarce and sold at fabulous prices. [illustration: fig. .--sprinkling pot sponge.--(_eucleptella aspergillum_.)] the skeleton is formed by small crystals and long threads of vitreous silica, cemented together, during life, by protoplasm. they are arranged in longitudinal and annular bands so as to form a long curved cylinder, about nine to twelve inches long, the walls of which are about one inch in thickness. the threads and bands are interwoven with the greatest regularity, and when the skeleton is freed from the adhering organic matter, it looks extremely beautiful. the mode in which the intersecting bunches of crystals are connected is shown in fig. . the upper end of the cylinder is closed by a perforated cover, which probably has given rise to the name of the sponge. the upper portion of the cylinder is surrounded by a few irregular, annular masses of organic tissue, which adheres loosely only to the skeleton. the lower end is formed by a bunch of long threads, rooting firmly in the ground. [illustration: fig. .--sponge crystals magnified.] up to about ten years ago the price of specimens of this sponge was very high. at that time, however, a colony of eucleptellas was found near the cities of cebu and manila, in the east indies, in a depth not exceeding fathoms, and since they have appeared in larger quantities in the market. it is remarkable that, contrary to their habits, these organisms have immigrated into regions to which they were totally unaccustomed. yet it must be regarded as a greater curiosity that they have been accompanied to their new abode by a few animals living in equally deep water and never met with before at depths less than three or four hundred fathoms. among these animals is a _phormosoma_ (water hedgehog), noted for its long spines. glass sponges are not confined to tropical regions. they are met with in latitudes as high as the färöe islands, where the beautiful _holtenia carpentaria_ abounds. it is represented in fig. . its cup-shaped skeleton is similar in structure to that of the _eucleptella_; numerous crystalline needles protrude from the surface of the upper part. lately some specimens of _holtenia_ have been found on the coast of florida. [illustration: fig. .--holtenia carpenteria.] glass sponges serve as dwellings for numerous animals, especially crustaceæ. a small shrimp inhabits the tubes of the _eucleptella_, a male and a female generally living together. they are shut up as in a prison in their crystalline home, as they are generally too large to pass through the meshes formed by the bundles of crystals. it was formerly believed that these skeletons had actually been built by the shrimps, and we can find no explanation for this curious circumstance, other than that the shrimps entered these habitations while very small and became too large to leave them. * * * * * plants protected by insects. mr. francis darwin, in a lecture on "means of self-defense among plants," delivered lately at the london institution, said that one of the most curious forms of defense known is afforded by a recently discovered class of plants, which, being stingless themselves, are protected by stinging ants, which make their home in the plant and defend it against its enemies. of these the most remarkable is the bull's-horn acacia (described by the late mr. belt in his book "the naturalist in nicaragua"), a shrubby tree with gigantic curved thorns, from which its name is derived. these horns are hollow and tenanted by ants, which bore a hole in them, and the workers may be seen running about over the green leaves. if a branch is shaken the ants swarm out of the thorns and attack the aggressor with their stings. their chief service to the plant consists in defending it against leaf-cutting ants, which are the great enemy of all vegetation in that part of america. the latter form large underground nests, and their work of destruction consists in gathering leaves, which they strip to form heaps of material, which become covered over with a delicate white fungus, on which the larvæ of the ants are fed, so that literally they are a colony of mushroom growers. the special province of the little stinging ants, which live in the thorns of the acacia, is, therefore, to protect the leaves of the shrub from being used by the leaf-cutters to make mushroom beds. certain varieties of the orange tree have leaves which are distasteful to the leaf-cutters, this property of the leaves thus forming a means of defense. other plants are unaccountably spared by them--grass, for example, which, if brought to the nest, is at once thrown out by some ant in authority. the bull's-horn acacia, in return for the service rendered by the stinging ants, not only affords them shelter in its thorns, but provides them with nectar secreted by glands at the base of its leaves, and also grows for them small yellow pear-shaped bodies, about one twelfth of an inch in length, at the tip of some of its leaflets, which they use as food. these little yellow bodies are made up of cells containing protoplasm rich in oil, and afford the insects an excellent food. when the leaf unfolds, the ants may be seen running from one leaflet to another, to see if these little yellow bodies are ripe; and if they are ready to be gathered they are broken up by the ants and carried away to the nest in the thorn. several small birds, also, build their nests in the bull's horn acacia, thus escaping from a predatory ant which is capable of killing young birds. the trumpet tree, another plant of south and central america, is also protected by a standing army of ants; and, like the above mentioned acacia, grows for its protectors small food bodies containing oil, but instead of secreting nectar in its leaves it harbors a small insect (coccus), whose sweet secretion is much relished by the ants. dr. beccari mentions an epiphytal plant growing on trees in borneo, the seeds of which germinate, like those of the mistletoe, on the branches of the tree; and the seedling stem, crowned by the cotyledons, grows to about an inch in length, remaining in that condition until a certain species of ant bites a hole in the stem, which then produces a gall-like growth that ultimately constitutes the home of the ants. if the plant is not fortunate enough to be bitten by an ant it dies. these ants, then, protect their plant home by rushing out fiercely on intruders, and thus are preserved the sessile white flowers which, in this plant, are developed on the tuber like body. * * * * * advance in iron.--at a meeting of the philadelphia iron merchants' association, march , prices of all descriptions of merchant iron were advanced fully per cent. * * * * * the aneroid barometer. the aneroid barometer was invented by m. vidi, of paris. it consists essentially of a circular box, the face of which is made of thin elastic metal, rendered more elastic by being stamped and pressed into concentric circular wave-like corrugations. this box is nearly exhausted of air, and its elastic face supports the pressure of the atmosphere, and yields to it with elastic resistance in proportion to the amount of pressure. thus, if the atmospheric pressure increases, the face is pressed inward; if atmospheric pressure diminishes, the elastic reaction of the metal moves the face outward. these movements are communicated to an index by suitable and very delicate mechanism, and registered in largely magnified dimensions, by the movements of this index upon the face of the dial. aneroid barometers are now made of pocket size, compensated for temperature, and with double scales, one reading the height of the barometer column, the other the elevation obtained. i have, says prof. w. m. williams, used one of these during many years, and find it a very interesting traveling companion. it is sufficiently sensitive to indicate the ascent from the ground floor to the upper rooms of a three-storied house, or to enable the traveler sitting in a railway train to tell, by watching its face, whether he is ascending or descending an incline. such slight variations are more easily observed on the aneroid than on the mercurial barometer, and therefore it is commonly stated that the aneroid is the more sensitive instrument. this, however, is a fallacious conclusion. it is not the superior sensitiveness of the movements of the instrument, but the greater facility of reading them, that gives this advantage to the aneroid, the index of which has a needle point traveling nearly in contact with the foot of the divisions; the readings are further aided by a needle point register attached to a movable rim, which may be brought point to point against the index, thus showing the slightest movement that human vision may detect. a magnifying lens may be easily used in such a case. it should be understood that the aneroid barometer is not an independent instrument; it is merely a device for representing the movements of the mercurial barometer. it is regulated by comparison with the primary instrument, and this comparison should be renewed from time to time, as the elastic properties of the metal may and do vary. an adjusting or regulating screw is attached to the back of the instrument, and is usually movable by a watch key. besides this, the magnified reading of course magnifies any primary error, and is largely dependent on the accuracy of the mechanism. * * * * * the albo-carbon light. we need hardly remind our readers that numerous unsuccessful attempts have been made at various times to enrich ordinary coal gas by the aid of volatile oils. upon the present occasion we have to place before them particulars of a process having the same object in view, but which is so far dissimilar in that it deals with a solid substance instead of a liquid oil. the invention has been brought into its present practical shape by mr. james livesey, c. e., of no. victoria chambers, westminster, in conjunction with mr. kidd, with whom it originated. the process consists in the employment of a substance called albo-carbon, which is the solid residuum of creosote. this material is moulded into the form of candles, which in large lamps are placed in a metallic vessel or receiver near the gas burner. the albo-carbon is warmed by the heat of the burning gas, the heat being transmitted to the receiver by a metallic conductor. upon the albo-carbon being raised to the necessary temperature it volatilizes, and as the coal gas passes over it to the burner its vapor becomes mingled with the gas, and greatly raises its illuminating power. of course when first lighted the coal gas only is burned, but in a few minutes the albo-carbon communicates its enriching vapor to it. the only alteration necessary to the present gas fittings is the vaporizing chamber, which is of simple construction, although at present the details of the various arrangements necessary for the different kinds of lights have not yet been fully worked out. this invention is now being tried experimentally in the eastern section of the westminster aquarium, where we recently examined it, and found it to afford a marked improvement upon the ordinary system of gas illumination, although a smaller number of burners is being used. tried alternately with ordinary coal gas, the higher illuminating power of the albo-carbon light was very remarkable. it appears that there are burners fitted at the aquarium with the new light, and these successfully take the place of ordinary gas burners previously in use. the illuminating effect is stated to be doubled, with an additional advantage as regards economy. the reduction of cost arises from the smaller quantity of gas consumed with the albo-carbon process than without it, and the very small cost of the enriching material. according to our information, , cubic feet of ordinary gas as generally used will, by the albo-carbon appliance, give as much illumination as , cubic feet without it, and the cost of the material to produce this result is only s. d. experiments have been made with this light by mr. t. w. keates, the consulting chemist to the metropolitan board of works, who reports very favorably upon it, as does also dr. wallace, of glasgow, who has obtained some very satisfactory results with it. it is claimed for the albo-carbon material that it is perfectly inexplosive, safe and portable, that it causes no obstruction and leaves no residuum, and that the receivers can be replenished almost indefinitely without any accumulation taking place, so perfect is the evaporation of the albo-carbon. on the whole the display at the aquarium speaks greatly in favor of the new process of gas enrichment, which, other things being equal, bids fair to find its way into practice.--_engineering._ * * * * * english and american hardware. mr. frederick smith, manager of the union land and building company (limited), recently read a paper on the above subject before the manchester scientific and mechanical society. mr. h. whiley, superintendent of the manchester health department, presided. the following is the text of the paper, as given in the london _ironmonger_. the lecturer said: a spectator in any of our courts of justice will generally be struck with the amount of hard swearing which is given to the court, under the name of evidence. he will find one set of witnesses testifying, under oath, to one thing, and another set, also under oath, to the very opposite. some prove too much, some too little, some are of a totally negative character, proving nothing, and some are of no character at all, and therefore are willing to prove anything. to some extent the same phenomena are to be observed in reference to the question of foreign competition. on the one hand the manufacturers hold up to our affrighted vision the picture of our mills stopped, our machine shops standing empty and idle, our hardware trade slipping through our fingers, our ships rotting in our own and in foreign ports, and our greatness as a producing nation for ever passed away. on the other hand, the journalists who take the labor side of the question, the trades-union leaders, and a large number of the workmen themselves, hold that we have little or nothing to fear from our foreign rivals; that the depression, like those atmospheric ones of which our american cousins are constantly warning us, will pass away, and leave us with better times to follow. i will, therefore, as far as possible, keep out of the region of speculation, give you a few facts, show you some examples, and leave you to draw your own inferences. some two or three years ago ordinary axle pulleys of english make were difficult to get; the price was scandalously high, and the quality as scandalously low. out of a dozen probably four would not turn round without sticking, and the casting was--well, simply vile. i show you a sample rather above the average, and the retail price for this inferior article was s. per gross. all at once the americans deluged the english market with the pulley which i now show to you, and it needs no explanation of mine to satisfy the mechanical minds present of the superiority of the transatlantic article; but when we also bear in mind that the price of the american was from to per cent less than the english pulley, you can understand how the builders exulted, and how the volscians of the birmingham district were fluttered. then, and not till then, would the english maker condescend to believe that it was possible to improve upon the wretched things which he had foisted upon his customers, and he at once commenced to copy the american pulley. he has not yet succeeded in producing such a beautiful casting, but i venture to say that he has improved the quality more in the last eighteen months than in the previous eighteen years. now take the ordinary door furniture. for generations the english builder and householder has had to be content with the stereotyped, with all its aggravating propensities. first, the little screw (so small as to be scarcely perceptible to touch or to sight) shakes loose from its countersunk depression in the spindle, gets lost, and lets the knob go adrift; or next, the knob itself, formed of a bit of sheet brass, turns round on its shank and the door cannot be opened, or the shank, not having a sufficient bearing on the spindle, works loose, and the whole thing is out of repair. it is the same thing to-day as it was when it tormented my grandfather; for, of course, no improvement could be made until uncle sam sent us his cheap, strong, serviceable, and sensible "mineral knob." the english maker says: "but look at the many devices which we have invented for door furniture." granted, and some of them very good, but none of them so good as this--for the money. plenty of them well adapted for extraordinary use, but none of them cheap enough and strong enough to be placed in competition with this in fitting up the dwelling of the ordinary englishman. the spindle and furniture of a lock is the portion which is liable to and receives the most rough usage. i have here an ordinary cheap set of china furniture of english make, which i dare not drop lest i should break it, but as you see, i dare throw its yankee competitor the whole length of this room. the retail price of this english set is ninepence--the price of the american is less than sixpence. the english spindle is fitted with the usual little screw, the knob is loose, the roses are china, and liable to break with the least strain or blow. the american set, as you see, has a long shank; the form of the knob is a very oblate spheroid, giving a good grip and free play for the fingers between the knob and the door. the rose is japanned iron, and has small studs or teeth projecting on its inner side effectually preventing it from turning round with the spindle; the screw is strong, and is tapped through the spindle itself, insuring both security and perfect steadiness. several small washers are supplied with each spindle, enabling the slack to be taken up perfectly, and at the same time preventing the spindle from sticking with any ordinary amount of friction. i will now show you a cheap american rim lock. first, you will notice that both sides are alike. next, that by pulling the latch forward it can be turned half round, and is thereby converted from a right hand to a left hand, or _vice versa_, in an instant. this is an important point to a builder, but our lockmakers do not seem to know it. several attempts have been made to introduce locks of this kind, but the fancy prices put upon every article which departs, in ever so slight a measure, from the antediluvian patterns mostly used, practically prohibits their adoption. the carcass of the lock is of cast iron; the casting, like all the small american castings, is simply perfect; bosses are cast round the follower and keyholes; the box staple is one piece of metal, neat and strong. but there is another point, and, to my mind, the most important one. whatever opinions may be held as to the relative quality of this lock, whether it is better or worse than an english one, it is at least an honest article. it makes no pretensions to be any better than it is. it does not entrap the unwary purchaser by pretending to be a first-class article, when at the same time it may be a swindle. i will now show you an ordinary inch rim-lock of english manufacture. at a short distance it looks like a superior article; the follower and keyhole appear as if they were bushed with brass. but let us take it to pieces, and see what we can find. the follower is a rough casting, not turned at the bearings, and is in no sense a fit. the screw holes are not countersunk, but merely punched in; the key is of the roughest and worst fitting description; the inside is as rough and cheap as possible; the key is cut so as to deceive the purchaser into the belief that there are twice as many wards in the lock as is really the case, and the bushes prove to be thin plates of brass riveted on, and not bushes at all. in short, the whole article is a vile fraud, and the maker was a swindler. this is strong language, but i think you will agree with me when i maintain that it is not stronger than the circumstances warrant. but there are still its defects of bad design and useless workmanship. the lock is of the usual form given to the english rim-lock, that is, it has a flange which requires to be let into the edge of the door. i have fixed hundreds of them, and have never yet been able to see a use for this flange. it is one great obstacle to the general introduction of a reversible lock; it adds to the labor of fixing without adding to the security of the door, for if the door is to be forced from the outside, the box staples give way first; if from the inside, the unscrewing of the box staple is all that is necessary to give egress; if the door requires easing, it effectually prevents it being done--in fact, it is a nuisance, and nothing but a nuisance. but our lockmakers do not appear to give these things a thought; their doctrine seems to be, "as it was in the beginning, is now, and ever shall be." again, notice that the edges of the iron which lie against the door and the sham bushes are ground bright. here is labor wasted, for as soon as the lock is fixed these polished portions are hidden for ever. next, take the box staple. as is usual, it is fearfully and wonderfully made up of sheet iron, square iron, and brass; the outcome of which is that the showy brass striking piece comes unriveted, the door comes unfastened, and the tenant's temper comes unhinged. why, in the name of common sense, could they not substitute a neat malleable casting? in our own houses i have long since discarded the ordinary box staple for draw-back locks, and find it cheaper to buy a cast iron staple, and throw away the one supplied by the english lockmaker. bear in mind that i have shown neither of these locks as samples of high-class goods, but as samples of the furniture fixed in the houses of the working and middle classes of this country; and when i tell you that the american lock, fitted with the mineral furniture, is at least per cent cheaper than the english abortion i have shown to you, you will begin to realize what our english markets have to fear from the americans. here is a common, cheap english mortise lock, and you will naturally ask why the outside of this lock is ground bright, when it is buried in the door and never seen except it has to be taken out for repairs. i have asked the same question, and for years have paused for a reply. this lock is not reversible, the follower is not bushed, and the inside is rough and cheap. contrast it with this neat american lock, and notice again the bosses to receive the wear; notice also that the bolts are brass; the latch-bolt is, of course, reversible--i never saw an american lock which was not. the body of the lock is cast iron; and, seeing that there are no strains upon a mortise lock, it is quite as good as if it was of wrought iron. there is no unnecessary grinding, but the iron is japanned, and the japan is as much superior to the english compound as is the lacquer ware of the japanese to that which is executed in birmingham and palmed upon the ignorant buyer as japanese work. in fact, as you can see for yourselves, the english japan looks almost like gas tar beside the american. this american lock is a two-lever, and there is no sham about the key, which is made of some kind of white metal and is small and neat. this lock is only ½ per cent higher in price than the english. before leaving these locks, let me say a word or two upon the relative wear upon their different portions, and their relative safety. the english maker appears to ignore the fact that nineteen-twentieths of the wear of a lock is upon the latch, spindle, and follower; the amount of actual wear upon the rest of the lock is comparatively slight. let any of you consider the number of times you open and close a door, compared with the times you lock it. our drawbacks and large rim locks are used about once a day; the great bulk of our mortise locks are not used, except as latches, once a week. one argument used by our manufacturers against the american lock is that, being made by machinery, there is necessarily a great duplication of parts, and a consequent lowering of the standard of security; while their own locks, being made by hand, are not alike, and therefore cannot be so easily opened. let any of you put this argument to proof, by trying how many front doors you can open with one key in a row of workmen's dwellings such as are found in manchester, ranging up to £ rentals, and the result will astonish you. if our own manufacturers made their locks sufficiently well to give this security, there would be some force in what they say; but so far as security is concerned, they might as well make their locks by machinery as make them in the way they do. i now show you two thumb latches, one of american and one of english make. notice the general finish of the american latch; the shape, the mode of construction, and everything about it proves that brains were used when it was designed and made. the english "norfolk latch," on the other hand, is ill designed, uncomfortable in hand, clumsily finished, the japan hangs about it in lumps, the latch is clumsy, the catch is clumsier, and the keeper, a rough piece of hoop iron, seems as if designed to "keep" the latch from doing its duty. in this case the american latch is per cent cheaper than the english one; and the english latch is of the same pattern as the one that was in use when i was a boy, only that it is a greatly inferior article. i will now introduce you to the well known nuisance which we have been accustomed to use for fastening our cupboard doors--the cupboard turn--and without further comment, ask you to compare it with this neat and simple latch of american make, costing about per cent more, twice as efficacious, and five times as durable. in this case no improvement has been made in the english fastener. it is just as it was when i went to the trade, about years ago, and although many attempts have been made to improve it they have added so much to its cost as to prevent the improved articles from coming into general use. the difference between the english and american inventor and designer seems to consist in this--that while an englishman devotes all his energies to the improvement of an existing shape, the american throws the old article under his bench and commences _de novo_. i think i have made out a case against the english hardware manufacturer, but when i have pointed these matters out to merchants and ironmongers, i have been met with various reasons for this manifest inferiority. i do not know how far these excuses may be valid, but one man says that the reason, as regards locks, is somewhat as follows: the locksmiths of the district wherein they are made in many cases work at their own homes; one man making one part of a lock, while other men make other parts. this goes on generation after generation, and the men become mere machines, not knowing how the entire lock is constructed, and not caring to know. another attributes it to the influence of the trades-unions, and says that if a manufacturer wants a different kind of lock, the price for the work is immediately put higher, even though the actual labor may not be increased. a third says it is due to the drunkenness of the hands, and their consequent poverty and physical and social demoralization, which prevents them from rising to such an intellectual level as will enable them to see the evils of their system, and adopt the right means to remove them. a fourth boldly says, "we make these goods because our customers want them." how far the reasons assigned by the first three are correct i am unable to say, but for the fourth, the extent to which the builders of england have patronized the americans is a complete answer. this defense, "our customers want them," is as old as the hills, and has been used to cover every kind of deception and inferior article ever manufactured. our lancashire manufacturers use it when they are charged with sending china clay and mildew (and call it calico) for the mild hindoo and the heathen chinee to dress themselves in. our butter merchants use it when they make up grease and call it butter; and our hardware merchants use it when they send us sham locks, and call them brass bushed, etc. it is the duty of the manufacturer to invent for his customers, and it is preposterous to say that the builder would prefer that embodiment of fraud--the english rim-lock, which i showed to you--to the american lock, which, at any rate, was an honest article, especially when the latter had the great advantage of being considerably cheaper. i am afraid that the swindling and greed of our merchants is having the effect of thrusting us out of the markets of the world, including our home markets; and when it is too late, these men who are making the name of english goods a byword and a reproach, even among the hindoos, the chinese, and the untutored savages of the south sea islands, will find that "honesty is the best policy." we have been accustomed to hear a deal of buncombe talked about the honesty of the englishman, and the want of honesty of the yankee; about the enterprise of our manufacturers and the skill of our workmen; but if what i have shown to you is to be taken as a specimen, it is time we set our house in order. since commencing the paper i have read the discussion between messrs. chubb and hill, and am at a loss to know why messrs. chubb entered into the arena. if all the english makers tried to reach chubb's standard we should keep our markets, at least so far as high quality is concerned; and to see messrs. chubb acting as champions of the english lockmakers is something like seeing messrs. horrocks taking up the cudgels for those people who manufacture china clay and call it calico, the proportion of fiber in the material being just a little greater than that found in hair mortar. in conclusion, i wish it to be understood that i bring these facts before you in no exultant spirit. i am an englishman, and the future welfare of myself and my children depends very much upon the future of english manufactures; but we cannot be blind to the fact that the apathy and conservatism of our manufacturers, the greed of our merchants, and the ignorance and drunkenness of our workmen, are weighing us so heavily in the race for trade that a member of our own family, whose leading business should be to produce food for us, is outstripping us with the greatest ease. our boasted supremacy as a manufacturing people is leaving us, and leaving us under such humiliating circumstances--and if the men of birmingham and the district are content to dwell in their present "fools' paradise," it is the duty of every lover of his country to speak as plainly as possible to them. of course i am prepared to be told that as i am not a lockmaker my opinion is worthless; but i have been about years as man and boy, employer and workman, in the building trade, and if i have not got to know something about builders' hardware during that period, i have made but a poor use of my time. i do not know if i have added to your stock of knowledge, but deeming the subject an important one, i have done the best i could in the time at my disposal. in the discussion which followed the opinion of the members present was unanimously in favor of the american articles shown to them. * * * * * a high indian official reports that the people of cashmere are dying of famine like flies, and at the present rate of mortality the province will be nearly depopulated by the end of the year. * * * * * to inventors. an experience of more than thirty years, and the preparation of not less than one hundred thousand applications for patents at home and abroad, enable us to understand the laws and practice on both continents, and to possess unequaled facilities for procuring patents everywhere. in addition to our facilities for preparing drawings and specifications quickly, the applicant can rest assured that his case will be filed in the patent office without delay. every application, in which the fees have been paid, is sent complete--including the model--to the patent office the same day the papers are signed at our office, or received by mail, so there is no delay in filing the case, a complaint we often hear from other sources. another advantage to the inventor in securing his patent through the scientific american patent agency, it insures a special notice of the invention in the scientific american, which publication often opens negotiations for the sale of the patent or manufacture of the article. a synopsis of the patent laws in foreign countries may be found on another page, and persons contemplating the securing of patents abroad are invited to write to this office for prices, which have been reduced in accordance with the times, and our perfected facilities for conducting the business. address munn & co., office scientific american. * * * * * business and personal. _the charge for insertion under this head is one dollar a line for each insertion; about eight words to a line. advertisements must be received at publication office as early as thursday morning to appear in next issue._ valves and hydrants, warranted to give perfect satisfaction. chapman valve manuf. co., boston, mass. brown & sharpe, prov., r. i. best gear teeth cutters and index plates at low prices. send for catalogue. wanted--galvanic battery, induction coil, electro-magnet. address, with description and price, box , boston, mass. new steam governor.--entire right for $ , . for circulars address e. towns, cisne, ill. gutta percha, pure and sheeted, for sale in quantities to suit. anderson & reynolds, salem, mass. the new fragrant vanity fair cigarettes. new combinations of rare old perique and virginia. wanted--second-hand corliss engine, to h. p. address p. o. box , new haven, conn. and in. gibed rest screw lathes. geo. s. lincoln, hartford, conn. "downer's anti-incrustation liquid" for removal and prevention of scales in steam boilers, is spoken of in highest terms by those who have given it a thorough trial. circulars and price lists furnished on application. a. h. downer, peck slip, new york. mr. w. b. adams, one of the most extensive contractors and decorators in this city, says he has used nearly fifty thousand gallons of h. w. johns' asbestos liquid paints, and after an experience of twenty years with white lead and other paints, he considers them not only superior in richness of color and durability, but owing to their wonderful covering properties, they are fully per cent more economical than any others. new pamphlet of "burnham's standard turbine wheel" sent free by n. f. burnham, york, pa. gaume's electric engine. pearl st., b'klyn, n. y. engines, ½ to h. p. g. f. shedd, waltham, mass. clipper injector. j. d. lynde, philadelphia, pa. diamond drills, j. dickinson, nassau st., n. y. eagle anvils, cents per pound. fully warranted. case hardening preparation. box , willimantic, ct. vertical burr mill. c. k. bullock, phila., pa. sheet metal presses, ferracute co., bridgeton, n. j. mundy's pat. friction hoist. eng., of any power, double and single. said by all to be the best. j. s. mundy, newark, n. j. auction sale.--the machinery and property of the well known hardie's machine works, and church st., albany, n. y., will be sold march , at noon. no postponement. to manufacturers or capitalists.--a rare chance to control a valuable agricultural patented implement. address s. a. fisher, maplewood, mass. reflecting telescope, ½ inches aperture, well mounted, price only $ . j. ramsden, philadelphia, pa. see hogins' laundry table, illustrated on page . state, canada, and entire right for sale. emery.--best turkey emery in bbls., kegs, and cases in quantities to suit. greene, tweed & co., park place, n. y. the scientific american export edition is published monthly, about the th of each month. every number comprises most of the plates of the four preceding weekly numbers of the scientific american, with other appropriate contents, business announcements, etc. it forms a large and splendid periodical of nearly one hundred quarto pages, each number illustrated with about one hundred engravings. it is a complete record of american progress in the arts. gold, silver, and nickel plater wants situation. address plater, oakville, conn. amateur photo. apparatus, including instructions; outfits complete. e. sackmann & co., pearl st., n. y. outfits for nickel and silver plating, $ to $ . union silver plating company, princeton, ill. send for circulars of indestructible boot and shoe soles to h. c. goodrich, hoyne ave., chicago, ill. for sale.--brown & sharp universal milling machine; bement profiling machine; first-class d hand machine tools. e. p. bullard, dey st., new york. for sale.-- foot bed putnam planer, $ . a. a. pool & co., newark, n. j. bevins & co.'s hydraulic elevator. great power, simplicity, safety, economy, durability. liberty st. n. y. a cupola works best with forced blast from a baker blower. wilbraham bros., , frankford ave., phila. shaw's noise quieting nozzles and mercury pressure gauges. t. shaw, ridge ave., philadelphia, pa. for solid wrought iron beams, etc., see advertisement. address union iron mills, pittsburgh, pa., for lithograph, etc. h. prentiss & company, dey st., n. y., manufs. taps, dies, screw plates, reamers, etc. send for list. presses, dies, and tools for working sheet metal, etc. fruit & other can tools. bliss & williams, b'klyn, n. y. nickel plating.--a white deposit guaranteed by using our material. condit, hanson & van winkle, newark, n. j. hydraulic elevators for private houses, hotels, and public buildings. burdon iron works, brooklyn, n. y. the lathes, planers, drills, and other tools, new and second-hand, of the wood & light machine company, worcester, are to be sold out very low by the george place machinery agency, chambers st., new york. hydraulic presses and jacks, new and second hand. lathes and machinery for polishing and buffing metals e. lyon & co., grand st., n. y. solid emery vulcanite wheels--the solid original emery wheel--other kinds imitations and inferior. caution.--our name is stamped in full on all our best standard belting, packing, and hose. buy that only. the best is the cheapest. new york belting and packing company, and park row, n. y. pulverizing mills for all hard substances and grinding purposes. walker bros. & co., d & wood st., phila., pa. portland cement--roman & keene's, for walks, cisterns, foundations, stables, cellars, bridges, reservoirs, breweries, etc. remit cents postage stamps for practical treatise on cements. s. l. merchant & co., broadway, new york. needle pointed iron, brass, and steel wire for all purposes. w. crabb, newark, n. j. manufacturers of improved goods who desire to build up a lucrative foreign trade, will do well to insert a well displayed advertisement in the scientific american export edition. this paper has a very large foreign circulation. band saws, $ ; scroll saws, $ ; planers, $ ; universal wood workers and hand planers, $ , and upwards. bentel, margedant & co., hamilton, ohio. the best friction clutch pulley and friction hoisting machinery in the world, to be seen with power applied, and liberty st., new york. d. frisbie & co., new haven, conn. c. m. flint, fitchburg, mass., mfr. of saw mills and dogs, shingle and clapboard machines. circulars. blake's belt studs; strongest, cheapest, and best fastening for leather or rubber belts. greene, tweed & co., new york. no gum! no grit! no acid! anti-corrosive cylinder oil is the best in the world, and the first and only oil that perfectly lubricates a railroad locomotive cylinder, doing it with half the quantity required of best lard or tallow, giving increased power and less wear to machinery, with entire freedom from gum, stain, or corrosion of any sort, and it is equally superior for all steam cylinders or heavy work where body or cooling qualities are indispensable. a fair trial insures its continued use. address e. h. kellogg, sole manufacturer, cedar st., new york. the unprecedented demand for kinney bros.' new cigarette, sweet caporal, is a good recommendation as to their merit. wheels and pinions, heavy and light, remarkably strong and durable. especially suited for sugar mills and similar work. pittsburgh steel casting company, pittsburgh, pa. deoxidized bronze. patent for machine and engine journals. philadelphia smelting co., phila., pa. for sale.-- h. p. vertical engine and boiler (new york safety steam power co.'s make), as good, and in some respects better, than new. address h. m. quackenbush, herkimer, n. y. wood-working machinery, waymouth lathes. specialty, wardwell patent saw bench; it has no equal. improved patent planers; elevators; dowel machines. rollstone machine company, fitchburg, mass. galland & co.'s improved hydraulic elevators. office broadway, n. y., (evening post building, room .) the only economical and practical gas engine in the market is the new "otto" silent, built by schleicher. schumm & co., philadelphia, pa. send for circular. dead pulleys that stop the running of loose pulleys and their belts, controlled from any point. send for catalogue. taper sleeve pulley works, erie, pa. _vick's illustrated monthly magazine_ is one of the most beautiful magazines in the world. each number contains a chromo of some group of flowers, and many fine engravings. published monthly at $ . per year. address james vick, rochester, n. y. * * * * * [illustration: notes and queries] notes & queries hints to correspondents. no attention will be paid to communications unless accompanied with the full name and address of the writer. names and addresses of correspondents will not be given to inquirers. we renew our request that correspondents, in referring to former answers or articles, will be kind enough to name the date of the paper and the page, or the number of the question. correspondents whose inquiries do not appear after a reasonable time should repeat them. persons desiring special information which is purely of a personal character, and not of general interest, should remit from $ to $ , according to the subject, as we cannot be expected to spend time and labor to obtain such information without remuneration. * * * * * ( ) s. q.--the speed of a circular saw at the periphery should be from , to , feet per minute. the number of revolutions per minute will of course vary with the diameter of the saw. ( ) t. j. f. asks ( ) for the best way to fasten emery on a wooden wheel, to be used in place of a solid emery wheel. a. cover the wheel with leather devoid of grease, and coat the leather surface, a portion at a time, with good glue; immediately roll the glued surface in emery spread out on a board. . how can i fasten small pieces of looking glass on iron? a. use equal parts of pitch and gutta percha together. ( ) w. c. asks: . what is the power of the simple electric light described in supplement no. ? a. when supplied with a strong current it is equal to or -foot gas burners. it is designed for temporary use only. . what is the cost of manufacturing the dynamo-electric machine in supplement no. ? a. the one shown in the article referred to cost about $ . ( ) l. d. asks: . which is the better conductor, silver or copper? a. silver. . and the comparative resistance offered to the electric current by water and the above? a. taking pure silver as , , , the conductivity of distilled water would be . . ( ) h. j. f. writes: in supplement a simple electric light is described. i wish to light a room × × feet. . how large is the bell glass? a. ½ inches. . can i use battery carbon? a. use a carbon pencil made for electric lamps. . how can i make tray water tight after putting wire through? a. with gutta percha. . i have one large cell bunsen and one smee. how many more and of what kind shall i get? a. one of the batteries described in supplements , , , will do, probably or bunsen elements would be the best. ( ) w. b. f. writes: i tried to make an electric pen, like the one described in your scientific american, of february d, , using a smee's battery, a circuit breaker, and an induction coil, but it did not work. is there anything wrong, or is a condenser different from an induction coil? a. a condenser consists of a number of sheets of tin foil separated from each other by larger sheets of paper. one half of the tin foil sheets are connected with one terminal of the primary coil, the other half with the other terminal; the tin foil sheets connected with one terminal alternate with those of the other terminal. the condenser is essential to the working of the coil. for complete directions for making induction coils, see scientific american supplement no. . ( ) j. de f. asks: . knowing the resistance of a wire of given conductivity, length, and diameter, will the resistance of any other wire be in proportion inversely? a. yes. . is there heat enough developed in the secondary coil of an induction coil to prevent the use of paraffine as an insulating material? a. with proper battery power, no. . how high in the list of non-conductors does paraffine stand? a. it is one of the best. . will a cotton insulator soaked in paraffine answer as well as silk? a. no, because it renders the covering of the wire too thick. . can you recommend any insulating material for making induction coils which will dry rapidly? a. alcoholic shellac varnish. rosin to which a little beeswax has been added is an excellent insulator; it must be applied in a melted state. . what is the composition of the black material covering the leclanche porous cell? a. gutta percha. . is the magneto-electric machine described in the scientific american supplement patented? a. to which do you refer? most, if not all of them are patented. ( ) b. v. f. writes: with reference to item , on page , of scientific american, march , , i think there is some mistake about the coal you think required to heat , cubic feet space. i burn some tons coal to heat, in the whole year, such part of my house as must exceed × × = , cubic feet. we keep up a moderate heat at night. ventilate more than most families do; take part only of the cool air, and only in part of the coldest weather, from the cellar, which at such times is opened into the main entries. house wood, back plastered, and stands alone. if lbs. coal would heat , feet one day, i ought to burn lbs. a day, or nearly tons in december and more in january. a. we are glad to receive these data, which correspond quite closely with some obtained by recent accurate experiments. the estimate given in the scientific american also agrees well with experiments on the use of hot air heaters for very small buildings or rooms. of course, the larger the space to be heated, the more economically it can generally be done. ( ) w. m. s. asks: will the coil described in supplement no. do for the electric pen described in a recent number of the scientific american? if not how must it be changed? a. it is too large; make it one half the size given. [illustration] ( ) b. g.--in reply to your inquiry as to mr. stroh's telephone experiment, we give the following, which we clip from the _english mechanic_: a singular experimental effect, of special interest just now from its possible bearing on the theory of the source of sound in the bell telephone, has just been observed by mr. stroh, the well known mechanician. if a telephone, t, with the circuit of its coil left open, be held to the ear, and a powerful magnet, m, be moved gently up and down along the length of the magnet, as shown by the arrow, and at a distance of an inch or two from it, a faint breathing sound will be heard, the recurring pulses of sound keeping time with the up and down motion of the magnet. the sound may be aptly compared to the steady breathing of a child, and there is a striking resemblance between it and the microphonic sounds of gases diffusing through a porous septum as heard by mr. chandler roberts. we understand that professor hughes is investigating the cause of this curious sound by help of the microphone. ( ) "enterprise" asks: what part of its volume will iron expand in passing from a temperature of ° to melting temperature? a. the cubical expansion of iron for each degree (c.) between ° and ° is . of its volume, its volume being . this ratio however, increases somewhat at higher temperatures, since the mean coefficient of expansion for each degree between ° c. and ° c. is . . the question you ask has probably never been settled. you may form an approximation by the use of the above ratios, knowing the melting point of the iron. ( ) p. l. o. asks for a good chemistry for a beginner to study without a teacher. a. fownes' "chemistry;" gorup-besanez, "inorganic, organic and physiological chemistry." ( ) l. e. m. asks: what is the best method of keeping fine guns from rusting, and what oil should be used? a. for the outside, clear gum copal part, oil of rosemary part, absolute alcohol parts. clean and heat the metal and apply a flowing coat of the liquid by means of a camel's hair brush. do not handle until the coat becomes dry and hard. for the inside of the barrel a trace of refined sperm oil is as good as anything, but an excess should be avoided. ( ) a. h. b. asks how much weight, falling feet, will be required to produce one horse power for five hours? a. one horse power for hours = , × = , , foot pounds--so that the weight required is , , ÷ = , lbs. ( ) a. d. r. asks: . in renewing a leclanche battery, do the zincs have to be amalgamated? a. they are usually amalgamated. . will two cells large size leclanche battery give any light, using the simple lamp described in supplement no. ? a. no. ( ) h. l. j. writes: in a recent issue of the scientific american you state that the floating of solid iron on melted iron is on the same principle as the floating of ice in water. i do not quite understand how it can be. please explain. a. solid iron, at an elevated temperature, floats upon molten iron for the same reason that ice floats upon molten ice-water--because it is specifically lighter. you will find the subject discussed at length in tyndall's "heat as a mode of motion." ( ) j. w. will find full directions for canning corn, etc., on p. ( ), vol. , scientific american. ( ) "amateur" writes: i wish to make some small bells that have a clear ring. what metal or metals can i use that i can melt easily? a. use an alloy of tin and antimony. see scientific american supplement no. . ( ) h.--a nutritious mixed diet is unquestionably the best, care being taken to avoid an excess of meat. ( ) w. f. writes: i have made an engine, and would like to find out what size of boiler it will require. the cylinder has ¼ inch bore and inches stroke. a. it depends upon pressure and speed to be maintained; probably a vertical tubular boiler, inches diameter, and to inches high, would suit you. ( ) r. g. (salt lake).--please send full name. ( ) j. m. g. asks: if two persons each pull one hundred pounds on opposite ends of a rope, what will be the strain on the rope? a. the strain on the rope will be lbs. ( ) w. m. m. asks: in laying off a mill stone in furrows, what draught is given? what amount of the space of a stone is given to furrows and what to grinding surface? a. there is considerable difference in the practice of various millers, and we would be glad to receive communications from those experienced in the art of dressing millstones. minerals, etc.--specimens have been received from the following correspondents, and examined, with the results stated: s. (new orleans.)--the powder consists of a mixture of zinc oxide and finely powdered resin. a quantitative analysis would be necessary to determine the proportions. any numbers of the scientific american supplement referred to in these columns may be had at this office. price cents each. * * * * * communications received. life preserving stone. by j. d. w. on ventilation. by d. w. what is mental action? by n. k. panama railroad or canal. by g. r. p. a problem. by k. on the gary motor. by g. f. m. magnetic motor. by g. w. w., w. a. a., g. h. f. house warming. by h. b. f. the injector. by m. a. b. columbus' problem; cure for diphtheria; the mullein cure for consumption. by r. w. l. a visit to tula. by l. r. on vacuum in pumps and the atwood machine. by p. j. d. on the patent bill. by r. * * * * * [official.] index of inventions for which letters patent of the united states were granted in the week ending february , , and each bearing that date. [those marked (r) are reissued patents.] a complete copy of any patent in the annexed list, including both the specifications and drawings, will be furnished from this office for one dollar. in ordering, please state the number and date of the patent desired, and remit to munn & co., park row, new york city. air heater, w. pickhardt , anchor, a. f. white , animal trap, s. j. bennett , axle box, vehicle, p. k. hughes , axle, carriage, c. h. kendall , axle for wagons, trussed, j. herby , axle, vehicle, c. h. kendall , barrel cover, c. brinton , bed bottom, j. flinn , bed bottom, spring, w. b. crich , bedstead, sofa, a. n. hornung , bedstead, wardrobe, h. p. blackman , belt hook templet, e. card , boot and shoe laster, l. graf , boot and shoe sole polisher, etc., o. gilmore , boot and shoe sole edge trimmer, c. h. helms , boot fronts, cutting in, c. h. colburn , boot, india-rubber, g. watkinson (r) , bottle filler, w. s. paddock , bread board, h. van doren , brick, shed for drying, c. h. roselius , bridge gate, a. stempel , broom corn tabler, g. w. foulger , button f. e. williams , calculator, tax, p. f. pettibone , car coupling, g. r. hamilton , car coupling, s. a. haydock , car coupling, j. worrall , car heaters, coupling for pipes of railway, j. w. graydon , car heater, railway, j. w. graydon , car heating pipe coupling, railway, j. w. graydon , car ventilation, j. knipscheer , cars, heating, j. & j. w. russell , cars, supplying water to wash stands on, d. h. jones , carbureter feed regulator, w. h. reed , card machine burr conveyer, w. c. bramwell , carpet beater, j. l. leach , carriage, c. h. palmer, jr. , carriage bow, f. h. niemann , carriage, child's, f. h. way (r) , carriage top prop, j. p. simpson , carriage canopy top, d. gleason , cartridge, w. w. hubbell , chair foot or leg rest, m. e. keiran , chimney, locomotive engine, h. r. walker , chuck, lathe, j. h. vinton , churn power motion, w. f. witherington , cigarette, c. c. millaudon , coat, reversible, n. h. lund , cock and faucet, etc., self-closing, j. broughton , coffee pot, teapot, etc., stand, d. h. murphy , coffee roaster, r. davis , corset, w. thomas , corset steel, e. m. smith , dental plugger, w. g. a. bonwill , door securer and combined tool, p. e. rudel , door sill and carpet strip, s. m. stewart , drip pan and self-oiler for bearings, r. b. eason , egg cup and opener, d. h. murphy , end gate, wagon, w. h. parkin , file, bill, e. h. owen , files, recutting, m. j. murphy , filter, j. w. lefferts , firearm, breech-loading, h. goodman , firearm lock, kaufmann & warnant , fire extinguisher, d. t. perkins , fires in buildings, extinguishing, c. barnes , fluid motor, chase & bowker , fountain tip, h. g. fiske , furnace, g. b. field , game apparatus, w. t. ebert , garter, etc., clasp, l. lobenstein , gate, mckinley & ellis , gate, g. w. pyle , glassware, decorating, h. feurhake , glassware shaper and finisher, atterbury & beck , glazier's tool, w. h. g. savage , governor and friction brake for machinery, speed, t. a. weston , grain drill, c. f. davis (r) , harness breeching strap, h. holt , harrow, toothless, j. w. mulvey , harvester, w. a. wood , harvester cutter, b. pratt , harvester, grain binding, j. f. appleby , harvester reel, b. moreland , harvesting machine, dutton & tornquist , hat formers, web tender for, r. eickemeyer , hay binder and elevator, p. h. nichols , hay elevator, h. barlow , hay tedder, e. j. knowlton , headlights, signal for locomotive, w. kelley (r) , heat regulator for furnaces, a. c. norcross (r) , hoisting bucket, f. h. c. mey , hoisting drums, etc., friction brake and clutch for, t. a. , weston hoisting machine, t. a. weston , horse toe weight, g. c. clausen , hydrant, j. snell , hydrant, street, g. c. morgan , hydraulic motor, w. s. puckett , injector, steam boiler, g. r. buckman , keg trussing machine, e. & b. holmes , kettle, h. c. mclean , kitchen cabinet, c. a. adams , lamp, j. h. irwin , lamp burner, e. b. requa , lamp, fountain, c. stockmann , lamp shade holder, brown & taplin , lamp, street, j. stewart , lamp wick, h. halvorson , life preserver, t. richards , life preserver, r. e. rose , lock, w. e. forster , lock gate, d. risher, jr. , mechanical movement, c. b. hitchcock , metal tube maker, a. ball , middlings separator, j. schoonover , milker, cow, a. c. baldwin , millstone adjustment, s. p. walling , millstone curb or hoop, j. s. detwiler , miter machine, j. j. spilker , mop head, h. murch , needle eye polisher, george & payne , oil cup, f. lunkenheimer , ore concentrator, e. w. stephens , ore roaster, c. e. robinson , oven bottom and slide, j. jewett , oysters, board bank for fattening, f. lang , package or box filler, bolton & strieby , paper cutter, j. m. jones , paper folder, r. m. hoe , paper machines, method and apparatus for producing a vacuum in , the suction box of, dunn & hollister paper machines, wire guide for j. w. moore , paper making, treating pulp stock, s. & j. deacon , paper scorer and cutter, g. l. ingram , paper scorer and cutter, w. f. lodge , permutation lock dial screen, corbett & miller , picture exhibitor, a. l. high , pill machine, fort & moore , pipe wrench, s. w. hudson , pipe wrench with cutter, franklin & gilberds , plant protector, e. r. frederick , plants, etc., poison distributer for, g. townsend , planter and drill, check row, g. j. hyer , planter, corn, j. a. roderick , plow, e. walker , plow attachment, a. o. bement , plow cutter, a. aldrich , plow, sulky, j. r. whitney , printer's roller, t. m. fisher , printing machine, l. c. crowell , pumping engine, duplex, g. f. blake (r) , radiator for steam heaters, covert & snyder , railway crossing, bernard & perkins , railway switch, c. f. gessert , ratchet mechanism and clutch for machinery, t. a. weston , rocking chair, j. w. hamburger , rotary engine, a. b. haughey , rubber mat, e. l. perry , sad iron holder, a. failor , safety pin, i. w. stewart (r) , salt cellar, w. sellers , sandpaper roll, o. gilmore , sash cord guide, clarkson & kesler (r) , sash fastener, j. benson , sash fastener, g. w. cary , sash fastener, j. b. morris , saw, circular, g. schleicher , saw handle, e. r. osgood , saw, jig, g. w. gary , saw mill, gang, h. d. & e. n. wickes , saw mill head block, j. t. james , sawing machine, scroll, n. p. selden , scales, platform, f. fairbanks , scales, weighing, g. l. c. coulon , scarf pins, etc., making ball heads of, j. n. allen , scythe snath fastening, p. e. rudel , sewer trap, j. p. cahill , sewing implement, a. j. lytle , sewing machine, c. o. parmenter , sewing machine attachment, j. b. sulgrove , sewing machine plaiter, white & bowhannan , sheet metal vessel bottom, f. w. moseley , shoe, searl & bly , skate, c. t. day (r) , skylight, j. friend , slate frame, e. butler (r) , sled propeller, g. f. shaver (r) , smelting furnace, iron, p. l. weimer , sole edge burnisher, t. p. young , spoke tenoning machine, a. j. roberts , sprinkling can, g. f. payne , stamp, postage and revenue, k. wheeler , staple machine, w. m. collins , staples in paper, etc., device for inserting metallic, g. w. , mcgill stave crozer and chamferer, h. h. dunlevy , steak tenderer, e. richmond , steam boiler, fire tube, j. cowhig , steam brake for locomotives, etc., w. l. card , steam piping for heating, etc., b. f. osborne , steam trap, i. w. merrill , stove and furnace grate, s. smyth , stove, cooking, g. h. hess , stove, cooking, j. jewett , stove, oil, fleming & hamilton , stove oven door and shelf, c. w. brieder , strainer, gravy, j. scheider (r) , strap for garments, adjusting, t. o. potter , street motor, j. t. cord , surveying instrument leveler, g. n. saegmuller , swing, j. ryan , telephone apparatus, speaking, e. gray , telephony, electric, black & rosebrugh , telephony, electric, a. m. rosebrugh , thill coupling, d. c. bacon , thill coupling, c. e. gillespie et al. , thill coupling, m. f. ten eyck , thill supporter, vehicle, h. o. rector , ticket, passenger, j. h. purdy , tiles for use as stands, frame for holding ornamental or fancy , pottery, c. a. wellington tiles, decorative, j. g. low , tiles, paving blocks, etc., composition for drain, w. h. haight , tire upsetter, b. k. taylor , tobacco, curing, a. p. poladura , tobacco cutter, bauer & seitz , tobacco flavoring compound, d. sternberg , tobacco manufacture, j. t. harris , tobacco presser, f. b. deane , traction engine, j. cooper , truss, j. r. alexander , type distributer, a. c. richards , type setter, a. c. richards , umbrella, m. girbardt , umbrella runner, w. h. belknap , undershoe or slipper, g. gardner , vehicle seat lock, w. g. allen , vehicle spring, m. h. crane , vehicle spring bolster, j. g. snyder , velocipede, e. c. f. otto , wash boiler, f. j. boyer , washing and bath tub, j. b o. shevill , washing machine, j. w. patterson , water meter diaphragm, w. b. mounteney , whip holder, curtis & worden (r) , wire measurer and cutter, g. a. baron , wire, winding tubes and rods with, a. ball , wrench, c. b. billings , * * * * * trade marks. boots, shoes, and brogans, w. f. thorne & co. , cigars, sullivan & burk , cigars, cigarettes, and smoking and chewing tobacco, b. hilson , cotton gins, printup, brother & pollard , fertilizers for flowers, w. h. bowker & co. , grain fans, j. montgomery , hair goods for ladies' wear, m. e. thompson , hoes, semple & birge manufacturing company , medicine for the cure of neuralgia, and the like diseases, j. s. nicolds , roofing paper, carpet paper, or paper felt, and building paper, watson & janes , soap, gallup & hewitt , spool cotton, j. & j. clark & co , table cutlery, john russell cutlery company , * * * * * designs. carpet, t. j. stearns , combined sleigh bell and terret ring, h. m. richmond , crocheted body for shawls, l. howard , oil cloth, c. t. & v. e. meyer , to , statue, a. bartholdi , * * * * * english patents issued to americans. from february to february , inclusive. bed bottoms, etc.--c. d. flynt, brooklyn, n. y. berth.--d. huston, boston, mass. lead smelting furnace.--g. t. lewis, philadelphia, pa. locks.--a. p. thomas _et al._, baltimore, md. railway joint.--p. t. madison, indianapolis, ind. spikes for railroads.--r. bocklen, new york city. ventilating buildings.--f. s. norton, new york city. * * * * * advertisements. inside page, each insertion cents a line. back page, each insertion $ . a line. (about eight words to a line.) _engravings may head advertisements at the same rate per line, by measurement, as the letter press. advertisements must be received at publication office as early as thursday morning to appear in next issue._ * * * * * a rare opportunity, on easy terms. to be sold at auction, at charleston, south carolina, on tuesday, the first day of april, , the taylor iron works, complete and in operation, together with all stores, stock, and work on hand on day of sale. the above is a large, first-class engineering establishment, complete within itself for all kinds of work, comprising iron and brass foundries, boiler shop, machine shops, pattern and millwright shops, with a large stock of patterns for local machinery, and taylor presses. connected with the works is a large, well-stocked engineer and mill supply store. all departments have the best of modern tools in thorough repair. buildings comparatively new, and conveniently arranged on large grounds. the business was established ; has always done a large business and maintained a high reputation. the present works, built since , have ample facilities to work men. at present about men are employed. for further particulars apply to the works or to john f. taylor, sharon springs, n. y., who will meet parties at albany, n. y., by appointment, or new york, if preferred. * * * * * largest assortment in the world of plays, dramas, comedies, farces, ethiopian dramas, plays for ladies only, plays for gentlemen only. wigs, beards, moustaches, face preparations, burnt cork, jarley's wax works, tableaux, charades, pantomimes, guides to the stage, and for amateurs make up book, make up boxes, new plays. sam'l french & son, east th st., union square, new york. catalogues sent free!!! * * * * * _latest style_ cards. _bouquet, lawn, floral,_ etc., in case, _name in gold_, c. seavy bros., northford, ct. [symbol: right index] rare opportunity. [symbol: left index] the proprietor, advanced in years and desirous of retiring from active control of business, would _sell at a bargain_, or convert into a joint stock company and retain an interest himself, a foundry and machine shops, with all their machinery and fixtures complete, and now crowded with custom work, having cost upwards of sixty thousand dollars, and the only ones of magnitude for miles on the mississippi river, on various points of which may be seen specimens of work of these shops at stillwater, winona, mcgregor. dubuque, fulton, lyons, clinton, muscatine, and on many of the boats. for particulars, address the proprietor at clinton, iowa. a. p. hosford. * * * * * for sale--gear cutter. been in use only eighteen months; will cut gears, both spur-bevel-miter and spiral, from four feet to one inch in diameter. is complete with counter-shaft and several cutters. machine made by pond, of worcester. index made by browne & sharpe. cost $ . will sell for $ . address j. g. stowe, main street, cincinnati, o. * * * * * the triumph non-conductor weighs but ½ lbs. to the square foot, and saves daily four pounds of coal. (asbestos saves but lbs.) price cts.-- cts. cash and cts. after satisfactory trial. agents wanted. for circulars showing why fuel is wasted and how to per cent., can be saved; also, how to construct reduction works for mineral ores of half the present weight and cost, to do three times the work with the fuel now used, and save per cent. of assay; also, the opinions of distinguished engineers, address b. f. smith, new orleans, la. * * * * * photo visiting cards--now all the rage in paris. one dozen beautiful gilt edged (round cornered) cards with your name and photograph, only cents; dozen, $ . full particulars and a -page book free. e. nason & co., nassau st., new york. * * * * * "bell" telephones. _any_ one can make in fifteen minutes. send three c. stamps for "where to get the parts, prices (total $ . per pair), and how put together." a. h. davis, hanover st., boston, mass. * * * * * catarrh. a sure cure. samples by mail, c. geo. n. stoddard, buffalo, n. y. it cures others. _it will cure you_. sample will prove. * * * * * any number of opportunities to buy what you want or sell or exchange what you don't want, in the _property journal_. send c. for copy. anderson & co., broadway, new york. * * * * * novelties, notions, watches, cheap jewelry, stationery packages. agents and country stores supplied. illustrated circular _free_. j. bride & co., manufacturers, salesroom, b'way, new york. address letters to p. o. box . * * * * * for universal lathe dogs, die dogs, etc., send for circular to c. w. le count, s. norwalk, ct. * * * * * ice-house and cold room.--by r. g. hatfield. with directions for construction. four engravings. supplement no. . price, cents. * * * * * send for our priced and illustrated catalogues. part st--mathematical instruments, pages; contains list and prices of drawing instruments, drawing materials, pocket compasses, surveying compasses, engineers' transits and levels, surveying chains, tape measures, pocket rules, and books relating to drawing, engineering, and mechanics. part d--optical instruments, pages; contains list and prices of spectacles, eye glasses, lenses, spy glasses, telescopes, opera and field glasses, graphoscopes, stereoscopes, camera obscuras, camera lucidas, microscopes, microscopic preparations, and books on optics and microscopy. part d--magic lanterns and slides, pages; contains list and prices or magic lanterns for toys, for public and private exhibitions, sciopticons, stereopticons, scientific lanterns, and accessory apparatus to be used with them; magic lantern slides, both colored and uncolored. part th--physical instruments, pages; contains list and prices of instruments to illustrate lectures in every department of physics and chemical science, air pumps, electric machines, galvanic batteries, barometers, thermometers, rain gauges, globes, spectroscopes, auzoux's anatomical models, and books relating to scientific subjects. james w. queen & co., optical and philosophical instrument makers, chestnut st., philadelphia. * * * * * wood-working machinery, such as woodworth planing, tonguing, and grooving machines, daniel's planers, richardson's patent improved tenon machines, mortising, moulding, and re-saw machines, and wood-working machinery generally. manufactured by witherby, rugg & richardson, salisbury street, worcester, mass. (shop formerly occupied by r. ball & co.) * * * * * the driven well. town and county privileges for making driven wells and selling licenses under the established american driven well patent, leased by the year to responsible parties, by wm. d. andrews & bro., new york. * * * * * mining machinery. engines. boilers, pumps, coal and ore jigs, dust burning appliances. drawings and advice free to customers. jeanesville iron works (j. c. haydon & co.). address howell green, supt., jeanesville, luzerne co., pa. * * * * * it pays to sell our rubber hand printing stamps. goods delivered in any country. circulars free. g. a. harper & bro., cleveland, o. * * * * * for ten dollars cash, we will insert a seven-line advertisement one week in a list of weekly newspapers, or four lines in a different list of papers, or ten lines two weeks in a choice of either of four separate and distinct lists containing from to papers each, or four lines one week in all four of the same lists, or one line one week in all six lists combined, being more than , papers. we also have lists of papers by states, throughout the united states and canada. send cents for our page pamphlet. address geo. p. rowell & co., newspaper advertising bureau, spruce street, new york. * * * * * machinery at very low prices. d hand lathes, drills, planers, hand tools for iron work, new woodworth planing machines, resawing, tenoning, moulding machines, scroll saws, portable steam engine. jos. r. blossom, ass'e, matteawan, n. y. * * * * * the george place machinery agency machinery of every description. chambers and reade streets, new york. * * * * * chromo and perfumed cards [no alike], name in gold and jet, c. clinton bros., clintonville, ct. * * * * * roof painting. for $ , by post office order or express, i will send the recipe for making langhorne's english gum coating paint and other mineral paints, with full instructions for roof and sidewall painting. this paint is used by the u. s. government. address m. langhorne, e street, washington, d. c. * * * * * for sale.--letters patent of wilhide's celebrated noiseless self-setting rat and mouse traps. thoroughly introduced. traps sold by all dealers. address owners and manufacturers, j. t. wilhide & bro., york road, carroll co., md. * * * * * important for all corporations and manf'g concerns.--buerk's watchman's time detector, capable of accurately controlling the motion of a watchman or patrolman at the different stations of his beat. send for circular. j. e. buerk, p. o. box . boston, mass n. b.--the suit against imhaeuser & co., of new york, was decided in my favor, june , . a fine was assessed against them nov. , , for selling contrary to the order of the court. persons buying or using clocks infringing on my patent will be dealt with according to law. * * * * * spare the croton and save the cost. driven or tube wells furnished to large consumers of croton and ridgewood water. wm. d. andrews & bro., water st., n. y., who control the patent for green's american driven well. * * * * * a new and valuable work for the practical mechanic and engineer. appletons' cyclopÆdia of applied mechanics. a dictionary of mechanical engineering and the mechanical arts. illustrated by , engravings. _edited by park benjamin, ph.d._ this valuable work is now being published in semi-monthly parts, at fifty cents each. active agents wanted. for terms and territory address geo. w. davis, care of d. appleton & co., new york. * * * * * caveats, copyrights, trade marks, etc. messrs. munn & co., in connection with the publication of the scientific american, continue to examine improvements, and to act as solicitors of patents for inventors. in this line of business they have had over thirty years' experience, and now have _unequaled facilities_ for the preparation of patent drawings, specifications, and the prosecution of applications for patents in the united states, canada, and foreign countries. messrs. munn & co. also attend to the preparation of caveats, trade mark regulations, copyrights for books, labels, reissues, assignments, and reports on infringements of patents. all business intrusted to them is done with special care and promptness, on very moderate terms. we send free of charge, on application, a pamphlet containing further information about patents and how to procure them; directions concerning trade marks, copyrights, designs, patents, appeals, reissues, infringements, assignments, rejected cases, hints on the sale of patents, etc. _foreign patents_.--we also send, _free of charge_, a synopsis of foreign patent laws, showing the cost and method of securing patents in all the principal countries of the world. american inventors should bear in mind that, as a general rule, any invention that is valuable to the patentee in this country is worth equally as much in england and some other foreign countries. five patents--embracing canadian, english, german, french, and belgian--will secure to an inventor the exclusive monopoly to his discovery among about one hundred and fifty millions of the most intelligent people in the world. the facilities of business and steam communication are such that patents can be obtained abroad by our citizens almost as easily as at home. the expense to apply for an english patent is $ ; german, $ ; french, $ ; belgian, $ ; canadian, $ . _copies of patents_.--persons desiring any patent issued from to november , , can be supplied with official copies at reasonable cost, the price depending upon the extent of drawings and length of specifications. any patent issued since november , , at which time the patent office commenced printing the drawings and specifications, may be had by remitting to this office $ . a copy of the claims of any patent issued since will be furnished for $ . when ordering copies, please to remit for the same as above, and state name of patentee, title of invention, and date of patent. a pamphlet, containing full directions for obtaining united states patents sent free. a handsomely bound reference book, gilt edges, contains pages and many engravings and tables important to every patentee and mechanic, and is a useful hand book of reference for everybody. price cents, mailed free. address munn & co., publishers scientific american, park row, new york. _branch office--corner of f and th streets, washington, d. c._ * * * * * practical draughtsman's book of industrial design and machinists' & engineers' drawing companion. forming a complete course of mechanical, engineering, and architectural drawing. from the french of m. armengaud the elder, professor of design in conservatoire of arts and industry, paris, and mm. armengaud the younger, and amoroux, civil engineers. rewritten and arranged with additional matter and plates, selections from and examples of the most useful and generally employed mechanism of the day. by william johnson, assoc. inst. c. e. illustrated by fifty folio steel plates, and fifty wood cuts. a new edition, to....$ among the contents are: linear drawing, definitions, and problems. sweeps, sections, and mouldings, elementary gothic forms, and rosettes. ovals, ellipses, parabolas, and volutes. rules and principal data. study of projections. elementary principles. of prisms and other solids. rules and practical data. on coloring sections, with applications. conventional colors, composition or mixture of colors. continuation of the study of projection--use of sections--details of machinery. simple applications--spindles, shafts, couplings, wooden patterns. method of constructing a wooden model or pattern of a coupling. elementary applications. rules and practical data. the intersection and development of surfaces, with applications.--the intersection of cylinders and cones. the delineation and development of helices, screws, and serpentines. application of the helix--the construction of a staircase. the intersection of surfaces--applications to stop cocks. rules and practical data. the study and construction of toothed gear.--involute, cycloid, and epicycloid. involute, cycloid. external epicycloid, described by a circle rolling about a fixed circle inside of it. internal epicycloid. delineation of a rack and pinion in gear. gearing of a worm with a worm wheel. cylindrical or spur gearing. practical delineation of a couple of spur wheels. the delineation and construction of wooden patterns for toothed wheels. rules and practical data. continuation of the study of toothed gear.--design for a pair of bevel wheels in gear. construction of wooden patterns for a pair of bevel wheels. involute and helical teeth. contrivances for obtaining differential movements. rules and practical data. elementary principles of shadows.--shadows of prisms, pyramids, and cylinders. principles of shading. continuation of the study of shadows. tuscan order. rules and practical data. application of shadows to toothed gear.--application of shadows to screws. application of shadow to a boiler and its furnace. shading in black--shading in colors. the cutting and shaping of masonry.--rules and practical data. remarks on machine tools. the study of machinery and sketching.--various applications and combinations: the sketching of machinery. drilling machines; motive machines; water wheels. construction and setting up of water wheels. delineation of water wheels. design of a water wheel. sketch of a water wheel. overshot water wheels. water pumps; steam motors; high-pressure expansive steam engine. details of construction; movements of the distribution and expansion valves; rules and practical data. oblique projections. parallel perspective. true perspective.--elementary principles. applications--flour mill driven by belts. description of the mill. representation of the mill in perspective. examples of finished drawings of machinery. [symbol: right index] the above, or any of our books, sent by mail, free of postage, at the publication price. our new and enlarged catalogue of practical and scientific books-- pages, vo.--sent free to any one who will furnish his address. henry carey baird & co., industrial publishers and booksellers, walnut street, philadelphia. * * * * * steam pumps. henry r. worthington, broadway, n. y. water st., boston. the worthington duplex pumping engines for water works--compound, condensing or non-condensing. used in over water-works stations. steam pumps--duplex and single cylinder. price list issued jan. , , with a reduction exceeding per cent. water meters. oil meters. * * * * * [illustration: truss] this new elastic truss has a pad differing from all others, is cup-shape, with self-adjusting ball in center, adapts itself to all positions of the body, while the ball in the cup presses back the intestines just as a person would with the finger. with light pressure the hernia is held securely day and night, and a radical cure certain. it is easy, durable and cheap. sent by mail. circulars free. eggleston truss co., chicago, ill. * * * * * the hancock inspirator testimonials. office of the hancock insp. co., london, eng., feb. , . i have just received an order from the english government for number inspirators--making machines in all for the government this month. b. h. warren, agent. * * * * * office of h. s. manning & co., liberty st., new york, feb. , . gentlemen: we have authority from mr. martin, chief engineer union ferry co., brooklyn, to state that they have inspirators at work on of their boats, feeding their main boilers, and all giving satisfaction, and to refer any one to him. yours truly, h. s. manning & co., agents. [symbol: right index] illustrated and descriptive circulars sent on application to hancock inspirator co., central wharf, boston. * * * * * [illustration: corrugated iron] this new moseley iron bridge and roof co. corrugated iron buildings, roofs, shutters, doors, iron sashes, skylights, etc. dey street, new york. * * * * * [illustration: crusher] this new blake's stone and ore breaker and crusher. for breaking hard and brittle substances to any size. endorsed by the leading mining, manufacturing, and railroad corporations in the united states and foreign countries. first premium wherever exhibited, and hundreds of testimonials of the _highest character_. a new size for prospecting and laboratory use. [symbol: right index] all stone crushers not made or licensed by us, containing vibratory convergent jaws actuated by a revolving shaft and fly-wheel, are infringements on our patent, and makers and users of such will be held accountable. address blake crusher co., new haven, conn. * * * * * [illustration: rival steam pumps. $ . and upwards john mcgowan & co. cincinnati, ohio. ] * * * * * pulmocura an absolute and unfailing remedy for consumption and all other diseases of the lungs and throat. mailed free on receipt of $ . a. a. martin, pulmocura man'f'g co., sole depot for the u. s., east th st., cor. broadway, new york. * * * * * soft, strong, and smooth iron or brass castings plain, galvanized, bronzed or nickled to order promptly. also patterns and models. light work a specialty. livingston & co., iron founders, pittsburg, pa. * * * * * [illustration: horse shoe] new steel horse shoe with level spring platform--continuous calk. the best in the world. cures tender and contracted feet, corns, interfering, quarter-crack lameness, and all evils resulting from the use of the common shoe. responsible men can make money selling this shoe. send for pamphlet. trial set with nails, $ . . to measure, place foot on paper, and draw pencil around. the john d. billings patent horse shoe company broadway, new york. * * * * * [illustration: steel stamps. n.y. stencil works, nassau st., n.y.] * * * * * lap welded charcoal iron boiler tubes, steam pipe, light and heavy forgings, engines, boilers, cotton presses, rolling mill and blast furnace work. reading iron works, south fourth st., phila. * * * * * phosphor-bronze bearings, pump-rods, and spring wire. [illustration: phosphor-bronze] apply to the phosphor-bronze smelting co., limited, washington ave., philadelphia, pa. * * * * * lathes, planers, shapers drills, bolt and gear cutters, milling machines. special machinery. e. gould & eberhardt, newark, n. j. * * * * * the best steam pump in america the deane made by holyoke machine co. more than in use. send for reduced price list. deane steam pump works liberty st., new york. * * * * * [illustration: gear wheels] small tools of all kinds; gear wheels, parts of models, and materials of all kinds. catalogues free. goodnow & wightman, wash'n st., boston, mass. * * * * * fine pamphlets printed for c. a page per , . , fine × circulars, $ . . price list or estimate and samples for stamp. bill heads, $ . "local" printing house, silver creek, n. y. * * * * * $ a month and expenses guaranteed to agents. outfit free. shaw & co., augusta, maine. * * * * * leffel water wheels. [illustration: water wheel] with recent improvements. prices greatly reduced. in successful operation. fine new pamphlet for sent free to those interested james leffel & co., springfield, o. liberty st., n. y. city. * * * * * [illustration: medal] paris, australia, phila., santiago, vienna, j. a. fay & co's wood working machinery was awarded at the paris exposition over all competitors the gold medal of honor. also highest award at phila., santiago, australia, and vienna. it is original in design, simple in construction, perfect in workmanship, saves labor, economizes lumber, and increases products of the highest standard of excellence. railroad, furniture, and agricultural implement shops, planing mills, etc., equipped at short notice, and the lowest cash prices. send for circulars. j. a. fay & co., cincinnati, ohio, u.s.a. * * * * * l. f. standish & co., screw manufacturers, builders of small machinery and fine tools. artisan st., new haven, ct. * * * * * [illustration: emery wheel.] emery wheel. new york belting and packing comp'y. the oldest and largest manufacturers of the original solid vulcanite emery wheels. all other kinds imitations and inferior. our name is stamped in full upon all our standard belting, packing, and hose. address new york belting and packing co., new york. john h. cheever, treas. * * * * * the seventh cincinnati industrial exposition opens for the reception of goods august th. opens to the public september th, and continues open until october th, in the new permanent buildings erected for the purpose. machinery tested and fully reported upon. send for rules and premium lists after april . h. mccollum, sec'y. * * * * * [illustration: amalgamating.] the forster-firmin gold and silver amalgamating comp'y of norristown, pa., will grant state rights or licenses or easy terms. this system works up to assay, and recovers the mercury rapidly. apply as above. * * * * * thomas's concentrated dye stuffs. ( recipes sent gratis.) (see scientific american supplement, march , ' .) address n. spencer thomas, elmira, n. y. * * * * * [illustration: rotary pressure blower.] baker rotary pressure blower. (forced blast) warranted superior to any other. wilbraham bros. frankford ave. philadelphia * * * * * "the injector." simple, durable, and reliable. requires no special valves. send for illustrated circular. wm. sellers & co., phila. * * * * * [illustration: cold rolled shafting.] the fact that this shafting has per cent. greater strength, a finer finish, and is truer to gauge, than any other in use renders it undoubtedly the most economical. we are also the sole manufacturers of the celebrated collins' pat. coupling, and furnish pulleys, hangers, etc., of the most approved styles. price list mailed on application to jones & laughlins, try street, d and d avenues, pittsburgh, pa. s. canal street, chicago, ill., and milwaukee. wis. [right index] stocks of this shafting in store and for sale by fuller, dana & fitz, boston, mass. geo. place machinery agency, chambers st., n. y. * * * * * vegetable and flower seeds we sell everything for the garden descriptive catalogues of pages sent free peter henderson & co. _ cortlandt st., new york._ flower and fruit plants * * * * * [illustration: engraving.] l. smith hobart, president. john c. moss, superintendent. type-metal relief plates. a superior substitute for wood-cuts at much lower prices. persons desiring illustrations for books, newspapers, catalogues, advertisements, or for any other purposes, can have their work done by us promptly and in the best style. our relief plates are engraved by photo-chemical means; are mounted on blocks type-high ready for use on any ordinary press, and will wear longer than the common stereotype plates. they have a perfectly smooth printing surface, and the lines are _as deep, as even,_ and _as sharp_ as they could possibly be cut by hand. electrotypes may be made from them in the same manner as from wood-cuts. copy. the engraving is done either from prints or pen-drawings. almost all kinds of prints can be re-engraved directly from the copy, provided they be in _clear, black lines_ or stipple, and on _white_ or only slightly tinted paper. pen drawings, suitable for engraving by us, must be made with _thoroughly_ black ink, on _smooth, white_ paper. they should usually be made twice the length and twice the width of the plates desired. when such drawings cannot be furnished us, we can produce them from photographs, pencil sketches, or designs of any kind accompanied with proper instructions. photographs taken in the usual way, and of any convenient size, we can use. change of size.--wood-cut prints of the coarser kind may often be reduced to half their lineal dimensions, while others will admit of very little reduction, and some of none at all. most lithographic and steel-plate prints will admit of no reduction. very fine prints of any kind may be _enlarged_ moderately without detriment. any prints which cannot be satisfactorily reduced or enlarged may be _redrawn_ and thus brought to any desired size. in all cases of reduction and enlargement, the relative proportions remain unchanged. proofs.--whenever desired, we will furnish tintype proofs of the drawings made by us, for approval or correction, before engraving. a printed proof is furnished with each plate. time.--we cannot usually engage to fill an order for a single plate in less than from three to six days; larger orders will require longer time. estimates will be promptly furnished when desired. that these may be definite and correct, the copy to be used--whether print, photograph, sketch, or drawing--should always be submitted for our examination, together with a distinct statement of the size of plate wanted, and of any other details to be observed. terms.--to insure attention, all orders must be accompanied by an advance of half the price charged, the balance to be paid on delivery. electrotyping and printing.--we have recently added to our establishment excellent facilities for making electrotypes, and also three power presses specially fitted for printing plates of all sizes in the finest manner. artificial light.--we have just introduced this most important facility, which enables us to prosecute our work _in cloudy weather_, and to push forward hurried orders _in the night_. references.--our plates are now used by the principal publishers in this city, and by most of the leading houses in every state in the union. our general circular contains a few specimens of the various kinds of our work, and will be sent on receipt of stamp. we have just prepared five special circulars, as follows: no. . portraits and figures. no. . buildings and landscapes. no. . machinery and apparatus. no. . maps, autographs, and ornamental lettering. no. . reproductions from wood-cuts, steel-plate prints, and lithographs. these will be furnished at _ten cents_ each. * * * * * advertisements. inside page, each insertion-- cents a line back page, each insertion--$ . a line. (about eight words to a line.) _engravings may head advertisements at the same rate per line, by measurement, as the letter press. advertisements must be received at publication office as early as thursday morning to appear in next issue._ adjustable incline presses. stiles & parker press co., middletown, conn. * * * * * [illustration: illustrated guide.] pages beautifully illustrated, mailed to all applicants inclosing cents. regular customers free. bliss' illustrated amateur's guide to the flower and kitchen garden, with colored chromo; pages, price cents. address b. k. bliss & sons, p. o. box , new york city. * * * * * to large consumers of fine light malleable iron castings, we can offer special inducements in the way of very superior quality guaranteed, and at fair prices. being ourselves large consumers and requiring the most perfect castings, other work is insured the same attention. mallory, wheeler & co., new haven, conn. * * * * * [illustration: lawn mower.] the philadelphia lawn mower _stands_ "_head of the class._" descriptive circulars and price lists sent on application. graham, emlem & passmore, patentees and manufacturers, market street, philadelphia, pa. * * * * * shafting pulleys, hangers, etc. a specialty. send for price list to a. & f. brown, - lewis street, new york. * * * * * air compressors, hoisting engines and other mining machinery; manufactured by griffith & wedge. zanesville, ohio. * * * * * mill stones and corn mills. we make burr millstones, portable mills, smut machines, packers, mill picks, water wheels, pulleys, and gearing, specially adapted to flour mills. send for catalogue. j. t. noye & son, buffalo, n. y. * * * * * how to sell patents.--this little book fully explains how all patents can be sold for good prices. price cents. l. d. snook, barrington, yates co., n. y. * * * * * pond's tools, engine lathes, planers, drills, &c., david w. pond, worcester, mass. * * * * * edmund draper, manufacturer of first-class engineers' instruments. established in . pear st., phila., pa. * * * * * j. lloyd haigh, manufacturer of [illustration: wire rope.] every description, for railroad and mining use, elevators, derricks, rope tramways, transmission of power, etc. no. john st., n. y. send for price list. plans and estimates furnished for suspension bridges. * * * * * the dingee & conard co's beautiful ever-blooming roses the best in the world. our great specialty is _growing_ and _distributing_ these beautiful roses. _we deliver_ strong pot plants, suitable for _immediate_ bloom, _safely by mail_ at all post-offices. splendid varieties, _your choice_, all labeled, for $ ; for $ ; for $ ; for $ ; for $ ; for $ ; for $ . [symbol: right index] send for our new guide to rose culture-- pages, elegantly illustrated--and _choose_ from over five hundred finest sorts. address the dingee & conard co., rose growers, west grove, chester co., pa. * * * * * how to sell patents. we send our page book of instruction, containing valuable information, free. send us your address. geo. c. tracy & co., cleveland, o. * * * * * [illustration: no more rheumatism or gout acute or chronic salicylica sure cure.] manufactured only under the above trade-mark, by the european salicylic medicine co., of paris and leipzig. immediate relief warranted. permanent cure guaranteed. now exclusively used by all celebrated physicians of europe and america, becoming a staple, harmless, and reliable remedy on both continents. the highest medical academy of paris report cures out of cases within three days. secret--the only dissolver of the poisonous uric acid which exists in the blood of rheumatic and gouty patients. $ . a box; boxes for $ . . sent to any address on receipt of price. endorsed by physicians. sold by all druggists. address washburne & co., only importers' depot. broadway, cor. fulton st., new york. * * * * * th annual statement of the equitable life assurance society of the u. s. henry b. hyde, president. for the year ending december , . amount of ledger assets, jan. , $ , , . less depreciation in government bonds, and appropriation to meet any depreciation in other assets , . -------- , , . income , , . -------- $ , , . disbursements. paid policy holders for claims by death, dividends, surrender values, discounted and matured endowments and annuities , , . other disbursements as per extended statement , , . -------- net cash assets, december , $ , , . assets. bonds and mortgages $ , , . real estate , , . united states stocks , , . state, city, and other stocks authorized by the laws of the state , , . loans secured by united states and other stocks , . cash and other ledger assets as per extended statement , , . ------------- $ , , . market value of stocks over cost , . accrued interest, rents, and premiums, as per extended statement , , . ------------- total assets, dec. , $ , , . total liabilities, including legal reserve for reinsurance of all existing policies , , . ------------- total undivided surplus $ , , . ------------- risks assumed in , , policies, assuring $ , , . n. b.--for the details of the above statement, see the society's "circular to policy holders," and other publications for . james w. alexander, vice-president. e. w. scott, superintendent of agencies. samuel borrowe, secretary. * * * * * [illustration: bolt cutters.] bolt cutters. send for catalogue of schlenker's automatic bolt cutters and screw cutting machines. howard iron works, buffalo, n. y. * * * * * big pay to sell our rubber printing stamps. samples free. taylor bros. & co., cleveland, o. * * * * * [illustration: la caisse generale of paris, france.] fire insurance exclusively. paid up capital $ , , . net surplus, dec. , , . cash assets in u. s. jan. , , . net assets in u. s. jan. , , . trustees in new york: louis de comeau, esq., of de rham & co. chas. coudert, jr., esq., of coudert bros. chas. renauld, esq., of renauld, francois & co. julien le cesne, resident secretary. t. j. temple, manager for the middle states. _western union building, n. y._ * * * * * the eclipse engine [illustration: eclipse engine.] furnishes steam power for all _agricultural_ purposes, _driving saw mills_, and for every use where a first-class and economical engine is required. eleven first-class premiums awarded, including centennial, ' . refer to no. , issue of ' , no. , issue of ' , of scientific american, for editorial illustrations. frick & co., waynesboro, franklin co., pa. when you write please name this paper. * * * * * the cameron steam pump, also known as the "special" pump, is the standard of excellence at home and abroad. for price lists, address cameron pump works, foot east d street, new york. * * * * * [illustration: foot lathe.] shepard's celebrated $ screw cutting foot lathe. foot and power lathes, drill presses, scrolls, circular and band saws, saw attachments, chucks, mandrels, twist drills, dogs, calipers, etc. send for catalogue of outfits for amateurs or artisans. h. l. shepard & co., , , & west front street, cincinnati, ohio. * * * * * established . joseph c. todd, engineer and machinist. flax, hemp, jute, rope, oakum and bagging machinery, steam engines, boilers, etc. i also manufacture baxter's new portable engine of . can be seen in operation at my store. a one horse-power portable engine, complete, $ ; two horse-power, $ ; two and a half horse-power, $ ; three horse-power, $ . manufactured exclusively by j. c. todd, barclay st., new york, or paterson, n. j. send for catalogue * * * * * steel castings, from ¼; to , lbs. weight, true to pattern, sound and solid, of unequaled strength, toughness and durability. an invaluable substitute for forgings or cast-iron requiring three-fold strength. send for circular & price list. chester steel castings co., evelina st., phila, pa. * * * * * [illustration: steel wire of every description & steel springs. cary & moen w. . st. new york city] * * * * * shafts, pulleys, hangers, etc. full assortment in store for immediate delivery. wm. sellers & co., liberty street, new york. * * * * * the lehigh valley emery wheel co., weissport, carbon co., pa. manufacturers of wheels and machines. * * * * * centennial and paris medals. mason's friction clutches and elevators. "new and improved patterns." per cent. off list. volney w. mason & co., providence, r. i., u.s.a. * * * * * ruffner & dunn, patentees and sole manufacturers of the excelsior steel tube cleaners. price $ . per inch. send for circular. schuylkill falls, phila., pa. * * * * * woodworth surface planers, $ . planers and matchers, $ . s. c. hills, chambers street, new york. * * * * * [illustration: columbia bicycle.] the columbia bicycle, made by the pope m'f'g co., summer street, boston. a practical road machine, easy to learn to ride, and when mastered one can beat the best horse in a day's run over an ordinary road. send c. stamp for price list and -page catalogue with full informat'n. * * * * * [illustration: bradford mill company cin. o.] bradford mill co. successors to jas. bradford & co., manufacturers of french buhr millstones, portable corn & flour mills, smu machines, etc. also, dealers in bolting cloths and general mill furnishings. office & factory, w. d st. cincinnati, o. j. r. stewart, _pres._ w. r. dunlap, _sec._ [symbol: right index] price lists sent on application. * * * * * second-hand boilers and machinery for sale.--boilers from to horse power, -horse power portable engine, one -inch lathe, two upright drills, blowers, etc., etc. for prices, etc., address james f. mann, utica, n. y. * * * * * wetherill & brother, philadelphia. pure white lead * * * * * rock drills. national drill and compressor co., liberty st., new york. air compressors to be run by steam, water power, or belt. * * * * * [illustration: foot power.] barnes' foot power machinery. different machines with which builders, cabinet makers, wagon makers, and jobbers in miscellaneous work can compete as to quality and price with steam power manufacturing; also amateurs' supplies. machines sent on trial. say where you read this, and send for catalogue and prices. w. f. & john barnes, rockford, winnebago co., ill. * * * * * nat'l bolt & pipe machinery co., mfrs. of hand and power bolt and pipe cutters, bolt pointers, bolt headers, hot and cold pressed nut machinery, taps and dies, etc. send for cir. cleveland, o. * * * * * [illustration: elevators hand power and hydraulic freight and passenger shafting pulleys & hangers s. graves & son rochester n.y.] * * * * * boiler coverings. with the "air space" improvements. the chalmers-spence co., foot e. th st., new york. sole owners of the air space patents. * * * * * the tanite co., stroudsburg, pa. emery wheels and grinders. london-- st. andrews st., holborn viaduct, e. c. liverpool-- the temple, dale st. geo. place, chambers st., new york agent. * * * * * [illustration: rock drilling machines and air compressors manufactured by burleigh rock drill co fitchburg mass. send for pamphlet.] * * * * * patents at auction. regular monthly sales. for terms, address n. y. patent exchange, liberty street, new york. * * * * * holly's improved water works. direct pumping plan. combines, with other advantages, over older systems, the following: . secures by variable pressure a more reliable water supply for all purposes. . less cost for construction. . less cost for maintenance. . less cost for daily supply by the use of holly's improved pumping machinery. . affords the best fire protection in the world. . largely reduces insurance risks and premiums. . dispenses with fire engines, in whole or in part. . reduces fire department expenses. for information by descriptive pamphlet, or otherwise, address the holly manufacturing co., lockport, n. y. * * * * * every man his own printer. [illustration: the excelsior.] the excelsior $ press prints labels, cards etc. (self-inker $ ) larger sizes for business, pleasure, young or old catalogue of presses, type, etc., for stamps. kelsey & co. meriden, conn. * * * * * pyrometers. for showing heat of ovens. hot blast pipes, boiler flues, superheated steam, oil stills, etc. henry w. bulkley, sole manufacturer, broadway, n. y. * * * * * machinists' tools. new and improved patterns. send for new illustrated catalogue. lathes, planers, drills, &c. new haven manufacturing co., new haven, conn. * * * * * [illustration: sanitary closet.] hermetical sanitary closet guaranteed absolutely water & gas tight send for circular john s. leng, fletcher st. n. y. * * * * * cigar box lumber, manufactured by our new patent process. the best in the world. spanish cedar, mahogany, poplar. also thin lumber of all other kinds, / to / in., at corresponding prices. all qualities. equal in all respects to any made, and at prices much under any to be obtained outside of our establishment. send for price list. geo. w. read & co., to lewis street, n. y. * * * * * bogardus' patent universal eccentric mills--for grinding bones, ores, sand, old crucibles, fire clay, guanos, oil cake, feed, corn, corn and cob, tobacco, snuff, sugar, salts, roots, spices, coffee, cocoanut, flaxseed, asbestos, mica, etc., and whatever cannot be ground by other mills. also for paints, printers' inks, paste blacking, etc. john w. thomson, successor to james bogardus, corner of white and elm sts., new york. * * * * * [illustration: watson pump.] the watson pump, for artesian, or deepwell pumping, piston rod, plunger & well rod in direct line machine simple, efficient. james watson. . s. front st. phila. * * * * * farm law. address of hon. edmund h. bennett, delivered before the massachusetts state board of agriculture. this is an essay embracing complete and practical information, valuable not only to the farmer but to every one. showing how to buy a farm: bargains that are not binding; boundaries, and where they are in streams, ponds, lakes, or on the seashore; what a deed of a farm includes; rights in the road. farm fences: their legal height, etc. railway fences. stray cattle; cattle on railways; impounding cattle. the farmer's liability for his animals. the law on the dog. the farmer not liable for his dogs. water rights and drainage; damming; diverting the course of a stream. surface water; underground water. trespassing, in summer and in winter. hunting and fishing. fruit trees on boundary lines, etc., etc. contained in scientific american supplement . price cents. * * * * * [illustration: wrought iron. beams & girders] the union iron mills. pittsburgh, pa., manufacturers of improved wrought iron beams and girders (patented). the great fall which has taken place in the prices of iron, and especially in beams used in the construction of fire proof buildings, induces us to call the special attention of engineers, architects, and builders to the undoubted advantages of now erecting fire proof structures; and by reference to pages & of our book of sections--which will be sent on application to those contemplating the erection of fire proof buildings--the cost can be accurately calculated, the cost of insurance avoided, and the serious losses and interruption to business caused by fire; these and like considerations fully justify any additional first cost. it is believed, that, were owners fully aware of the small difference which now exists between the use of wood and iron, in many cases the latter would be adopted. we shall be pleased to furnish estimates for all the beams complete, for any specific structure, so that the difference in cost may at once be ascertained. address carnegie, bros. & co., pittsburgh, pa. * * * * * ice at $ . per ton. the pictet artificial ice co., limited, room , coal and iron exchange, p. o. box , n. y. * * * * * [illustration: h. w. johns' asbestos] liquid paints, roofing, boiler coverings, steam packing, sheathings, fire proof coatings, cements, &c. send for descriptive price list. h. w. johns m'f'g co. maiden lane, n. y. * * * * * $ to $ invested in wall st. stocks makes fortunes every month. books sent free explaining everything. address baxter & co., bankers, wall st., n. y. * * * * * the "scientific american" is printed with chas. eneu johnson & co.'s ink. tenth and lombard sts., philadelphia, and gold st., new york. * * * * * transcriber's notes: [symbol: right index] and [symbol: left index] are used where the text had a picture of a hand with the index finger pointing right or left, respectively. table of contents: article named "buffalo, the domestication of" page was not included in the original. table of contents: article named "steamship, ocean, large" page was not included in the original. table of contents: article named "specimen, a rare geological" page was not included in the table of contents. [illustration] scientific american supplement no. new york, december , . scientific american supplement. vol. xiv., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. engineering and mechanics.--louis favre, constructor of the st. gothard tunnel.-- figures.--portrait and monument at turin to commemorate the tunneling of the alps the new harbor of vera cruz.--new artificial harbor for vera cruz.--capt. eads's plan.-- figure.--plan of harbor and improvement cost of power to make flour driving gear mechanism for lift hammers.-- figures de junker and ruh's machine for cutting annular wheels.-- figures recent hydraulic experiments.--results of experiments on the flow of water in the ganges canal the germ: shall it be retained in flour? by arthur atkins wheat tests ii. technology and chemistry.--apparatus for manufacturing gaseous or aerated beverages.-- figures.--bicarbonate of soda apparatus. generator. washer.--suction pump.--saturator.--apparatus for using carbonate of lime.--apparatus completely mechanical in operation detection and estimation of fusel oil on silicon.--curious formation of silicide of platinum stannous nitrates.--the formation of explosive compounds in machines by the corrosion of bronze and tin solder metallic thorium. by l.f. nilson friedrich wöhler.--obituary notice of the great german chemist apparatus for printing by the blue process. by channing whitaker.-- figures iii. electricity, light, heat, etc.--spectrum gratings a new pocket opera glass.-- figures atoms, molecules, and ether waves. by john tyndall. action of heat and light on molecules.--heat as an agent in exploring molecular conditions.--the results of a recent incursion into the extra-sensible world of atoms and molecules apparatus for measuring electricity at the upper school of telegraphy. by e. mercadier.-- figures. constant vibrator.--the electrical tuning fork. arrangement for testing electric piles.--very rapid electric tuning fork.--a vibrating micrometer iv. natural history.--our origin as a species. by richard owen.--the neanderthal skull.--differential characters between the lowest _homo_ and the highest _simia_ the aba or odika. by dr. w.h. bacheler.--a remarkable tree of west africa california cedars * * * * * apparatus for manufacturing gaseous or aerated beverages. the apparatus employed at present for making gaseous beverages are divided into two classes--intermittent apparatus based on chemical compression, and continuous ones based on mechanical compression. the first are simple in appearance and occupy small space, but their use is attended with too great inconveniences and losses to allow them to be employed in cases where the manufacture is of any extent, so the continuous apparatus are more and more preferred by those engaged in the industry. continuous apparatus, however, other than those that we now propose to occupy ourselves with, are not without some defects, for the gas is produced in them intermittingly and at intervals, and more rapidly than it is used, thus necessitating the use of a gasometer, numerous and large washers, complicated piping, and, besides, of an acid cock. to get rid of such drawbacks, it became necessary to seek a means of rendering the production of the gas continuous, and of regulating it automatically without the aid of the operator. mr. mondollot has obtained such a result through a happy modification of the primitive system of the english engineer bramah. he preserves the suction and force pump but, while applying it to the same uses, he likewise employs it, by the aid of a special arrangement, so as to distribute the sulphuric acid automatically over the chalk in the generator, and to thus obtain a regular and continuous disengagement of carbonic acid gas. the dangers and difficulties in the maneuver of an acid cock are obviated, the gasometer and its cumbersome accessories are dispensed with, and the purification is more certain, owing to the regularity with which the gas traverses the washers. in the accompanying plate we have figured three types of these apparatus. the first that we shall describe is arranged for the use of bicarbonate of soda. this apparatus consists ( ) of a _generator_, c d, ( ) of a double _washer_ g g, ( ) of a _suction pump_, p, and ( ) of a _saturator_, s (see figs to ). _the generator._--this consists of a cylindrical leaden receptacle, d, on the bottom of which rests a leaden bell containing apertures, c, at its base. a partition, c, into which is screwed a leaden tube, c, containing apertures divides the interior of the bell into two compartments. the upper of these latter is surmounted by a mouth, b, closed by a clamp, and through which the bicarbonate of soda is introduced. a definite quantity of water and sulphuric acid having been poured into the receptacle, d, a level tends to take place between the latter and the bell, c, the liquid passing through the apertures. but the acidulated water, coming in contact with the soda, sets free carbonic acid gas, which, having no exit, forces the water back and stops the production of gas until the apparatus is set in motion. at this moment, the suction of the pump causes a new inflow of acidulated water upon the soda, from whence another disengagement of gas, and then a momentary forcing of the water, whose level thus alternately rises and falls and causes a continuous production of gas proportionate with the suction of the pump. the consumption of soda and acid is about kilogrammes each for charging siphons or bottles. the bicarbonate is known to be used up when the liquid in the generator is seen to descend to the bottom of the water level, n, fixed to the vessel, d. _the washer_ (figs and )--the gas, on leaving the generator, enters the washer through a bent copper pipe, r. the washer is formed of two ovoid glass flasks g g, mounted on a bronze piece, l, to which they are fixed by screw rings, l, of the same metal. the two flasks, g g, communicate with each other only through the tinned-copper tube q, which is held in the mounting q, of the same metal. this latter is screwed into the piece, l, and contains numerous apertures, through which the gas coming in from the pipe, r, passes to reach the upper flask, g. the gas is washed by bubbling up through water that has been introduced through the cock, r. after it has traversed both flasks, it escapes through the copper pipe, p, into which it is sucked by the pump, p. _the pump_ (figs , and )--this consists of a cylindrical chamber, p, of bronze, bolted to a bracket on the frame, and cast in a piece, with the suction valve chamber, p, in which the valve, p, plays. it is surmounted by the distributing valve chamber p². this latter is held by means of two nuts screwed on to the extremity of the rods, p³, connected with the shell, e, of the distributing-cock, e. in the shell, e, terminates, on one side, the pipe, p, through which enters the gas from the washer, and, on the other, the pipe i, that communicates with a feed-reservoir not shown in the cuts. the cock e, permits of the simultaneous regulation of the entrance of the gas and water. its position is shown by an index e, passing over a graduated dial, _e¹_. from the distributing valve chamber, p² the pipe, s, leads the mixture of water and gas under pressure into _the saturator_, s (figs , and )--this consists of a large copper vessel, s, affixed to the top of the frame through the intermedium of a bronze collar h, and a self closing bottom h. this latter is provided with two pipes, one of which, s, leads the mixture of water and carbonic acid forced by the pump, and the other, b, communicates with the siphons or bottles to be filled. the pipe, b, is not affixed directly to the bottom, but is connected therewith through the intermedium of a cock, r. the object of the broken form of this pipe is to cause the pressure to act according to the axis of the screw, r, which is maneuvered by the key, r². the water under pressure, having been forced into the vessel, s, is submitted therein to an agitation that allows it to dissolve a larger quantity of gas. such agitation is produced by two pairs of paddles, j j, mounted at the extremity of an axle actuated by the wheel, a, through the intermedium of gearings, g and g. the course of the operation in the saturator may be followed by an inspection of the water level, n, seen at the front and side in figs. and . this apparatus, in which the pressure reaches to atmospheres in the manufacture of seltzer water or gaseous lemonade in bottles, and from to atmospheres in that of seltzer water in siphons, is provided also with a pressure gauge, m, and a safety valve, both screwed, as is also the tube, n², into a sphere, s, on the top of the saturator. _apparatus for using carbonate of lime_ (figs , , and )--when chalk is acted upon by sulphuric acid, there is formed an insoluble sulphate which, by covering the chalk, prevents the action of the acid from continuing if care be not taken to constantly agitate the materials. this has led to a change in the arrangement of the generator in the apparatus designed for the use of chalk. it consists in this case of a leaden vessel, d, having a hemispherical bottom set into a cylindrical cast iron base, k, and of an agitator similar to that shown in fig. , for keeping the chalk in suspension in the water. these latter materials are introduced through the mouth, b (fig. ). then a special receptacle, c, of lead, shown in detail in fig. , and the cock, c, of which is kept closed, is filled with sulphuric acid. the acid is not introduced directly into the vessel, c, but is poured into the cylinder, c, whose sides contain numerous apertures which prevent foreign materials from passing into the siphon tube c, and obstructing it. to put the apparatus in operation, the acid cock, c, is opened and the wheel, a, is turned, thus setting in motion both the pump piston, p, and the agitator, within s and d. then the play of the pump produces a suction in the washers and from thence in the generator and causes the acid in the vessel, c, to flow into the generator through the leaden siphon tubes, c. coming in contact with the chalk in suspension, the acid produces a disengagement of gas which soon establishes sufficient pressure to stop the flow of the acid and drive it back into the siphon tube. the play of the pump continuing, a new suction takes place and consequently a momentary flow of acid and a new disengagement of gas. thus the production of the latter is continuous, and is regulated by the very action of the pump, without the operator having to maneuver an acid-cock. the latter he only has to open when he sets the apparatus in operation, and to close it when he stops it. the arrangement of the washer is the same as in the preceding apparatus, save that a larger cylindrical copper reservoir, g', is substituted for the lower flask. the pump and saturator offer nothing peculiar. a bent tube, u, which communicates with the generator, d, on one side, and with a cylindrical tube, v, ending in a glass vessel on the other, serves as a safety-valve for both the generator and the acid vessel. the consumption of chalk is about . kilogrammes, and the same of acid, for charging siphons or bottles. the apparatus shown in the figure is capable of charging siphons or bottles per day. _an apparatus completely mechanical in operation_ (fig. ).--this apparatus consists of two very distinct parts. the saturator, pump, and driving shaft are supported by a hollow base, in whose interior are placed a copper washer and the water-inlet controlled by a float-cock. this part of the apparatus is not shown in the plate. the generator, partially shown in fig. , is placed on a base of its own, and is connected by a pipe with the rest of the apparatus. it consists of two similar generators, d, made of copper lined with lead, and working alternately, so as to avoid all stoppages in the manufacture when the materials are being renewed. the pipe, d, connecting the two parts of the apparatus forks so as to lead the gas from one or the other of the generators, whence it passes into the copper washer within the base, then into the glass indicating washer, and then to the pump which forces it into the saturator. each of the generators communicates by special pipes, a, with a single safety vessel, v, that operates the same as in the preceding apparatus. the agitator, q, is of bronze, and is curved as shown in fig. . the production of this type of apparatus is dependent upon the number of siphons that can be filled by a siphon filler working without interruption.--_machines, outils et appareils._ * * * * * detection and estimation of fusel oil. until quite recently we have had no accurate method for the determination of fusel oil in alcohol or brandy. in meurer suggested a solution of one part of silver nitrate in nine parts of water as a reagent for its detection, stating that when added to alcohol containing fusel oil, a reddish brown color is produced, and in case large quantities are present, a dark brown precipitate is formed. it was soon found, however, that other substances than amyl alcohol produce brown colored solutions with silver nitrate; and bouvier[ ] observed that on adding potassium iodide to alcohol containing fusel oil, the solution is colored yellow, from the decomposition of the iodide. subsequently böttger[ ] proved that potassium iodide is not decomposed by pure amyl alcohol, and that the decomposition is due to the presence of acids contained in fusel oil. more accurate results are obtained by using a very dilute solution of potassium permanganate, which is decomposed by amyl alcohol much more rapidly than by ethyl alcohol. [footnote : zeitschrift f. anal. chem. xi., .] [footnote : dingler's polytech. jour., ccxii., .] depré[ ] determines fusel oil by oxidizing a definite quantity of the alcohol in a closed vessel with potassium bichromate and sulphuric acid. after removal of excess of the oxidizing reagents, the organic acids are distilled, and, by repeated fractional distillation, the acetic acid is separated as completely as possible. the remaining acids are saturated with barium hydroxide, and the salts analyzed; a difference between the percentage of barium found and that of barium in barium acetate proves the presence of fusel oil, and the amount of difference gives some idea of its quantity. betelli[ ] dilutes c.c. of the alcohol to be tested with to volumes of water, and adds to drops of chloroform and shakes thoroughly. if fusel oil is present, its odor may be detected by evaporating the chloroform; or, by treatment with sulphuric acid and sodium acetate, the ether is obtained, which can be readily recognized. jorissen[ ] tests for fusel oil by adding drops of colorless aniline and to drops of hydrochloric acid to c.c. of the alcohol. in the presence of fusel oil a red color is produced within a short time, which can be detected when not more than . per cent. is present. but foerster[ ] objects to this method because he finds the color to be due to the presence of furfurol, and that pure amyl alcohol gives no color with aniline and hydrochloric acid. [footnote : pharm. j. trans. [ ] vi., .] [footnote : berichte d. deutschen chem. gesellsch., viii., .] [footnote : pharm. centralhalle, xxii., .] [footnote : berichte d. deutsch. chem. gesellsch., xv., .] hager[ ] detects fusel oil as follows: if the spirit contains more than per cent. of alcohol, it is diluted with an equal volume of water and some glycerine added, pieces of filter paper are then saturated with the liquid and exposed to the after the evaporation of the alcohol, the odor of the fusel oil can be readily detected. for the quantitative determination he distills c.c. of the alcohol in a flask of to c.c. capacity connected with a condenser, and so arranged that the apparatus does not extend more than cm. above the water bath. this arrangement prevents the fusel oil from passing over. if the alcohol is stronger than per cent., and the height of the distillation apparatus is not more than cm., the residue in the flask may be weighed as fusel oil. with a weaker alcohol, or an apparatus which projects further out of the water bath, the residual fusel oil is mixed with water. it can, however, be separated by adding strong alcohol and redistilling, or by treating with ether, which dissolves the amyl alcohol, and distilling, the temperature being raised finally to °. [footnote : pharm. centralhalle, xxii., .] marquardt,[ ] like betelli, extracts the fusel oil from alcohol by means of chloroform, and by oxidation converts it into valeric acid. from the quantity of barium valerate found he calculates the amount of amyl alcohol present in the original solution; c.c. of the spirit, which has been diluted so as to contain to per cent. of alcohol, are shaken up thoroughly with c.c. of chloroform, the aqueous layer drawn off, and shaken with a fresh portion of chloroform. this treatment is repeated several times. the extracts are then united, and washed repeatedly with water. the chloroform, which is now free from alcohol and contains all the fusel oil, is treated with a solution of grammes of potassium bichromate in grammes of water and grammes of sulphuric acid, and then heated in a closed flask for six hours on a water bath at °. the contents of the flask are then distilled, the distillate saturated with barium carbonate, and the chloroform distilled; the residue is evaporated to a small volume, the excess of barium carbonate filtered off, and the filtrate evaporated to dryness and weighed. the residue is dissolved in water, a few drops of nitric acid added, and the solution divided into two portions. in the first portion the barium is determined; in the second the barium chloride. the total per cent. of barium minus that of barium chloride gives the amount present as barium valerate, from which is calculated the per cent. of amyl alcohol. by this process the author has determined one part of fusel oil in ten thousand of alcohol. to detect very minute quantities of fusel oil, the chloroform extracts are treated with several drops of sulphuric acid and enough potassium permanganate to keep the solution red for twenty-four hours. if allowed to stand in a test tube, the odor of valeric aldehyde will first be noticed, then that of amyl valerate, and lastly that of valeric acid.--_amer. chem. journal._ [footnote : berichte d. deutsch. chem. gesellsch., xv., , and , .] * * * * * on silicon. it is known that platinum heated in a forge fire, in contact with carbon, becomes fusible. boussingault has shown that this is due to the formation of a silicide of platinum by means of the reduction of the silica of the carbon by the metal. mm. p. schützenberger and a. colson have produced the same phenomenon by heating to white heat a slip of platinum in the center of a thick layer of lampblack free from silica. the increase in weight of the metal and the augmentation of its fusibility were found to be due, in this case also, to a combination with silicon. as the silicon could not come directly from the carbon which surrounded the platinum, mm. schützenberger and colson have endeavored to discover under what form it could pass from the walls of the crucible through a layer of lampblack several centimeters in thickness, in spite of a volatility amounting to almost nothing under the conditions of the experiment. they describe the following experiments as serving to throw some light upon the question: . a thin slip of platinum rolled in a spiral is placed in a small crucible of retort carbon closed by a turned cover of the same material. this is placed in a second larger crucible of refractory clay, and the intervening space filled with lampblack tightly packed. the whole is then heated to white heat for an hour and a half in a good wind furnace. after cooling, the platinum is generally found to have been fused into a button, with a marked increase in weight due to taking up silicon, which has penetrated in the form of vapor through the walls of the interior crucible. . if, in the preceding experiment, the lampblack be replaced by a mixture of lampblack and rutile in fine powder, the slip of platinum remains absolutely intact, and does not change in weight. thus the titaniferous packing recommended by sainte-claire deville for preventing the access of nitrogen in experiments at high temperatures also prevents the passage of silicon. a mixture of carbon and finely divided iron is, on the contrary, ineffectual. these facts seem to indicate that nitrogen plays a part in the transportation of the silicon, as this is only prevented by the same means made use of in order to prevent the passage of nitrogen. . the volatility of free silicon at a high temperature is too slight to account for the alteration of the platinum at a distance. this can be shown by placing several decigrammes of crystallized silicon on the bottom of a small crucible of retort carbon, covering the silicon with a small flat disk of retort carbon upon which is placed the slip of platinum. the crucible, closed by its turned cover, is then enveloped in a titaniferous packing and kept at a brilliant white heat for an hour and a half. the metal is found to have only very slightly increased in weight, and its properties remain unaltered. this experiment was repeated several times with the same result. if, however, the crystallized silicon be replaced by powdered calcined silica, the platinum, placed upon the carbon disk, fuses and increases in weight, while the silica loses weight. the theory of these curious phenomena is very difficult to establish on account of the high temperatures which are necessary for their manifestation, but it may be concluded, at present, that nitrogen and probably oxygen also play some part in the transportation of the silicon across the intervening space, and that the carbosilicious compounds recently described by mm. schützenberger and colson also take part in the phenomenon.--_comptes rendus_, xciv., , .--_amer. chem. journal._ * * * * * stannous nitrates. at the royal powder works at spandau, prussia, frequent ignition of the powder at a certain stage of the process led to an examination of the machinery, when it was found that where, at certain parts, bronze pieces which were soldered were in constant contact with the moist powder, the solder was much corroded and in part entirely destroyed, and that in the joints had collected a substance which, on being scraped out with a chisel, exploded with emission of sparks. it was suspected that the formation of this explosive material was in some way connected with the corrosion of the solder, and the subject was referred for investigation to rudolph weber, of the school of technology, at berlin. the main results of his investigation are here given. the explosive properties of the substance indicated a probable nitro-compound of one of the solder metals (tin and lead), and as the lead salts are more stable and better understood than those of tin, it was resolved to investigate the latter, in hope of obtaining a similar explosive compound. experiments on the action of moist potassium nitrate on pure tin led to no result, as no explosive body was formed. stannous nitrate, sn(no_{ })_{ }, formed by the action of dilute nitric acid on tin, has long been known, but only in solution, as it is decomposed on evaporating. by adding freshly precipitated moist brown stannous oxide to cool nitric acid of sp. gr. . , as long as solution occurred, and then cooling the solution to - °, weber obtained an abundance of crystals of the composition sn(no_{ })_{ } + h_{ }o. they resemble crystals of potassium chlorate. they cannot be kept, as they liquefy at ordinary temperatures. an insoluble _basic_ salt was obtained by digesting an excess of moist stannous oxide in solution of stannous nitrate, or by adding to a solution of stannous nitrate by degrees, with constant stirring, a quantity of sodium carbonate solution insufficient for complete precipitation. thus obtained, the basic salt, which has the composition sn_{ }n_{ }o_{ }, is a snow-white crystalline powder, which is partially decomposed by water, and slowly oxidized by long exposure to the air, or by heating to °. by rapid heating to a higher temperature, as well as by percussion and friction, it explodes violently, giving off a shower of sparks. this compound is also formed when a fine spray of nitric acid (sp. gr. . ) is thrown upon a surface of tin or solder. it is also formed when tin or solder is exposed to the action of a solution of copper nitrate, and thus formed presents the properties already described. in this, then, we have a probable cause of the explosions occurring in the powder works; but the explanation of the formation of the substance is wanting, as potassium nitrate was shown not to give an explosive substance with tin. a thin layer of a mixture of sulphur and potassium nitrate was placed between sheets of tin and copper foil, and allowed to stand, being kept constantly moist. after a time the copper was found to have become coated with sulphide, while the tin was largely converted into the explosive basic nitrate. the conditions are obviously the same as those found in the powder machinery, where bronze and tin solder are constantly in contact with moist gunpowder. the chemical action is probably this: the sulphur of the powder forms, with the copper of the bronze, copper sulphide; this is oxidized to sulphate, which reacts with the niter of the powder, forming potassium sulphate and copper nitrate; the latter, as shown above, then forms with the tin of the solder the explosive basic nitrate, which, being insoluble, gradually collects in the joints, and finally leads to an explosion.--_journal für praktische chemie._ * * * * * metallic thorium. by l.f. nilson. the density of thorium as obtained by reducing the anhydrous chloride by means of sodium was found by chydenius, . to . . the author has obtained metallic thorium by heating sodium with the double anhydrous thorium potassium chloride, in presence of sodium chloride in an iron crucible. after treating the residue with water there remains a grayish, heavy, sparkling powder, which under the microscope appears to consist of very small crystals. metallic thorium is brittle and almost infusible; the powder takes a metallic luster under pressure, is permanent in the air at temperatures up to °, takes fire below a red heat either in air or oxygen, and burns with a dazzling luster, leaving a residue of perfectly white thoria. if heated with chlorine, bromine, iodine, and sulphur, it combines with them with ignition. it is not attacked by water, cold or hot. dilute sulphuric acid occasions the disengagement of hydrogen, especially if heated, but the metal is acted on very slowly. concentrated sulphuric acid with the aid of heat attacks the metal very slightly, evolving sulphurous anhydride. nitric acid, strong or weak, has no sensible action. fuming hydrochloric acid and _aqua regia_ attack thorium readily, but the alkalies are without action. the metal examined by the author behaves with the reagents in question the same as did the specimens obtained by berzelius. the mean specific gravity of pure thorium is about . hence it would seem that the metal obtained by chydenius must have contained much foreign matter. the specific gravity of pure thoria is . to . . the equivalent and the density being known, we may calculate the atomic volume. if we admit that the metal is equivalent to atoms of hydrogen, we obtain the value . . this number coincides with the atomic volumes of zirconium ( . ), cerium ( . ), lanthanum ( . ), and didymium ( . ). this analogy is certainly not due to chance; it rather confirms the opinion which i have put forward in connection with my researches on the selenites, on certain chloro-platinates and chloro-platinites, etc., that the elements of the rare earths form a series of quadrivalent metals. * * * * * [american chemical journal.] friedrich wÖhler. no one but a chemist can appreciate the full significance of the brief message which came to us a month ago without warning--"wöhler is dead!" what need be added to it? no chemist was better known or more honored than wöhler, and none ever deserved distinction and honor more than he. his life was made up of a series of brilliant successes, which not only compelled the admiration of the world at large, but directed the thoughts of his fellow workers, and led to results of the highest importance to science. it is impossible in a few words to give a correct account of the work of wöhler, and to show in what way his life and work have been of such great value to chemistry. could he himself direct the preparation of this notice, the writer knows that his advice would be, "keep to the facts." so far as any one phrase can characterize the teachings of wöhler, that one does it; and though enthusiasm prompts to eulogy, let us rather recall the plain facts of his life, and let them, in the main, speak for themselves.[ ] [footnote : see kopp's "geschichte der chemie," iv., .] he was born in the year at eschersheim, a village near frankfort-on-the-main. from his earliest years the study of nature appears to have been attractive to him. he took great delight in collecting minerals and in performing chemical and physical experiments. while still a boy, he associated with a dr. buch, of frankfort, and was aided by this gentleman, who did what he could to encourage in the young student his inclination toward the natural sciences. the first paper which bears the name of wöhler dates from this period, and is upon the presence of selenium in the iron pyrites from kraslitz. in he went to the university of marburg to study medicine. while there he did not, however, neglect the study of chemistry. he was at that time particularly interested in an investigation on certain cyanogen compounds. in he went to heidelberg, and in he received the degree of doctor of medicine. l. gmelin became interested in him, and it was largely due to gmelin's influence that wöhler gave up his intention of practicing medicine, and concluded to devote himself entirely to chemistry. for further instruction in his chosen science, wöhler went to stockholm to receive instruction from berzelius, in whose laboratory he continued to work from the fall of until the middle of the following year. only a few years since, in a communication entitled "jugenderinnerungen eines chemikers," he gave a fascinating account of his journey to stockholm and his experiences while working with berzelius. on his return to germany, he was called to teach chemistry in the recently founded municipal trade school (gewerbschule) at berlin. he accepted the call, and remained in berlin until , when he went to cassel to live. in a short time he was called upon to take part in the direction of the higher trade school at cassel. he continued to teach and work in cassel until , when he was appointed professor of chemistry in göttingen. this office he held at the time of his death, september , . in wöhler became acquainted with liebig, and an intimate friendship resulted, which continued until the death of liebig, a few years ago. though they lived far apart, they met during the vacations at their homes, or traveled together. many important investigations were conceived by them as they talked over the problems of chemistry, and many papers appeared under both their names, containing the results of their joint work. among such papers may be mentioned: "on cyanic acid" ( ); "on mellithic acid" ( ); "on sulphotartaric acid" ( ); "on oil of bitter almonds, benzoic acid, and related compounds" ( ); "on the formation of oil of bitter almonds from amygdalin" ( ); and "on uric acid" ( ). of the papers included in the above list, the two which most attract attention are those "on the oil of bitter almonds" and "on uric acid." in the former it was shown for the first time that in analogous carbon compounds there are groups which remain unchanged, though the compounds containing them may, in other respects, undergo a variety of changes. this is the conception of radicals or residues as we use it at the present day. it cannot be denied that this conception has done very much to simplify the study of organic compounds. the full value of the discovery was recognized at once by berzelius, who, in a letter to the authors of the paper, proposed that they should call their radical proin or orthrin (the dawn of day), for the reason that the assumption of its existence might be likened to the dawn of a new day in chemistry. the study of this paper should form a part of the work of every advanced student of chemistry. it is a model of all that is desirable in a scientific memoir. the paper on uric acid is remarkable for the number of interesting transformation products described in it, and the skill displayed in devising methods for the isolation and purification of the new compounds. comparatively little has been added to our knowledge of uric acid since the appearance of the paper of liebig and wöhler. it would lead too far to attempt to give a complete list of the papers which have appeared under the name of wöhler alone. in he made the remarkable discovery that when an aqueous solution of ammonium cyanate, cnonh_{ }, is evaporated, the salt is completely transformed into urea, which has the same percentage composition. it would be difficult to exaggerate the importance of this discovery. that a substance like urea, which up to that time had only been met with as a product of processes which take place in the animal body, should be formed in the laboratory out of inorganic compounds, appeared to chemists then to be little less than a miracle. to-day such facts are among the commonest of chemistry. the many brilliant syntheses of well-known and valuable organic compounds which have been made during the past twenty years are results of this discovery of wöhler. in he published a paper on secretion, in the urine, of substances which are foreign to the animal organism, but which are brought into the body. he discovered the transformation of neutral organic salts into carbonates by the process of assimilation. in he investigated the dimorphism of arsenious acid and antimony oxide. in he made the discovery that dimorphous bodies have different fusing points, according as they are in the crystallized or amorphous condition. among the more remarkable of his investigations in inorganic chemistry are those on methods for the preparation of potassium ( ); on tungsten compounds ( ); the preparation of aluminum ( ); of glucinum and yttrium ( ). in , working with ste. claire deville, he discovered crystallized boron. analytical methods were improved in many ways, and excellent new methods were introduced by him. further, he did a great deal for the improvement of the processes of applied chemistry. with liebig he was associated in editing the "annalen der chemie and pharmacie" and the "handwörterbuch der chemie." he wrote a remarkably useful and popular "grundriss der chemie." the part relating to inorganic chemistry appeared first in , and was in use until a few years ago, when fittig wrote his "grundriss" on the same plan, a work which supplanted its prototype. the above will serve to give some idea of the great activity of wöhler's life, and the fruitfulness of his labors. while thus contributing largely by his own work directly to the growth of chemistry, he did perhaps as much in the capacity of teacher. many of the active chemists of the present day have enjoyed the advantages of wöhler's instruction, and many can trace their success to the impulse gathered in the laboratory at göttingen. the hand of the old master appears in investigations carried on to-day by his pupils. wöhler's was not a speculative mind. he took very little part in the many important discussions on chemical theories which engaged the attention of such men as dumas, gerhardt, berzelius, and liebig, during the active period of his life. he preferred to deal with the facts as such; and no one ever dealt with the facts of chemistry more successfully. he had a genius for methods which has never been equaled. the obstacles which had baffled his predecessors were surmounted by him with ease. he was in this respect a truly great man. personally, wöhler was modest and retiring. his life was simple and unostentatious. he had a kindly disposition, which endeared him to his students, to which fact many american chemists who were students at göttingen during the time of wöhler's activity can cordially testify. in short, it may be said deliberately that wöhler, as a chemist and as a man, was a fit model for all of us and for those who will come after us. though he has gone, his methods live in every laboratory. his spirit reigns in many; could it reign in all, the chemical world would be the better for it. i.r. * * * * * louis favre, constructor of the st. gothard tunnel. it is now already a year that the locomotive has been rolling over the st. gothard road, crossing at a flash the distance separating basle from milan, and passing rapidly from the dark and damp defiles of german switzerland into the sun lit plains of lombardy. our neighbors uproariously fêted the opening of this great international artery, which they consider as their personal and exclusive work, as well from a technical point of view as from that of the economic result that they had proposed to attain--the creation of a road which, in the words of bismarck, "glorifies no other nation." as regards the piercing of the gothard, the initiative does, in fact, belong by good right to the powerful "iron chancellor," so we have never dreamed of robbing germany of the glory (and it is a true glory) of having created the second of the great transalpine routes, that open to european products a new gate to the oriental world. it seems to us, however, that in the noisy concert of acclamations that echoed during the days of the fêtes over the inauguration of the line, a less modest place might have been made for those who, with invincible tenacity and rare talent, directed the technical part of the work, and especially those kilometers of colossal boring--the great st. gothard tunnel, which ranks in the history of great public works side by side with the piercing of the frejus, and the marvelous digging of suez and panama. we recall just now the names of those who, during nearly ten years, have contributed with entire disinterestedness to the completion of this colossal work. over all stands a figure of very peculiar originality--that of m. louis favre, the general contractor of the great tunnel, whose name will remain attached to the creation of this work through the helvetian alps, like that of sommeiller to the great tunnel of the frejus, and that of de lesseps to the artificial straits that henceforward join the oceans. having myself had the honor of occupying the position of general secretary of the enterprise under consideration, i have been enabled to make a close acquaintance with the man who was so remarkable in all respects, and who, after passing his entire life in great public works, died like a soldier on the field of honor--in the depths of the tunnel. [illustration: louis favre.] [illustration: the downfall of the titans, conquered by the genius of man. (monument at turin to commemorate the tunneling of the alps.)] i saw favre, for the first time, in geneva, in , a few days after he had assumed the responsibility of undertaking the great work. he had been living since the war on his magnificent plongeon estate, on the right bank of the lake. there was no need of dancing attendance in order to reach the contractor of the greatest work that has been accomplished up to the present time, for m. favre was easy of access. we had scarcely passed five minutes together than we we were conversing as we often did later after an acquaintance of six years. after making known to him the object of my visit, the desire of being numbered among the _personnel_ of his enterprise, the conversation quickly took that turn of mirthfulness that was at the bottom of favre's character. "this is the first time," said he to me, laughing, "that i ever worked with germans, and i had not yet struck the first blow of the pick on the gothard when they began to quibble about our contract of the th of last august. ah! that agreement of august th! how i had to change and re-change it, later on. if this thing continues, we shall have a pretty quarrel, considering that i do not understand a word of the multiple interpretations of their _charabia_. i ought to have mistrusted this. but you see i have remained inactive during the whole of this unfortunate war. i was not made for promenading in the paths of a garden, and i should have died of chagrin if such inaction had had to be prolonged. when one lives, as i have, for thirty years around lumber yards, it is difficult to accustom one's self to the sedentary and secluded life that i have led here for nearly two years." as he said, with just pride, louis favre had, indeed, before becoming the first contractor of public works in the world, lived for a long time in lumber yards. the years that so many other better instructed but less learned persons, who were afterward to gladly accept his authority, had given up to their studies, favre had passed in the humble shop of his father, a carpenter at chêne, a small village at a half league from geneva. it soon becoming somewhat irksome for him in the village, he left the paternal workbench to start on what is called the "tour of france." he was then eighteen years of age. three years afterward, he was undertaking small works. it was not long ere he was remarked by the engineers conducting the latter, and he was soon called to give his advice on all difficult questions. between times, favre had courageously studied the principal bases of such sciences as were to be useful to him. in the evening, he made up at the public school what was lacking in his early instruction; not that he hoped to make a complete study for an engineer, but only to learn the indispensable. he was, before all things, a practical man, who made up for the enforced insufficiency of his technical knowledge by a _coup d'oeil_ of surprising accuracy. here it may be said to me that the piercing of the great st. gothard tunnel was accompanied by considerable loss. that is true, but it must be recalled also that this colossal work was accomplished amid the most insurmountable difficulties which ever presented themselves. in spite of this, the cost of the tunnel per running foot was also a third less than that of the great mont cenis tunnel. when favre undertook the st. gothard, he already reckoned to his credit numerous victories in the domain of public works, especially in the construction of subterranean ones. the majority of tunnels of any length which, since the beginning of the establishment of railways, have been considered as works of some proportions (the blaisy tunnel, for instance), were executed by him, in addition to other open air works. so favre reached the st. gothard full of hope. the battle with the colossus did not displease him, and his courage and his confidence in the success of the work seemed to increase in measure as the circumstances surrounding the boring became more difficult. in the presence of the terrible inundation of the gallery of airolo and the falling of aquiferous rocks, creating in the subterranean work so desperate a situation that a large number of very experienced engineers almost advised the abandonment of the works, favre remained impassive. amid the general apprehension, which, it may be readily comprehended, was felt in such a situation he made his confident and cheerful voice heard, reviving the ardor of all, and speaking disdainfully of "that insignificant gothard, which would come out all right." the _personnel_ of the enterprise were not the only ones, however, who were uneasy over the constantly occurring difficulties in the way of the work, for the company itself and the swiss federal council made known to favre their fears that the execution of the work would be delayed. he, however, calmed their fears, and exposed his projects to them, and the seances always ended by a vote of confidence in the future of the undertaking. favre certainly did not dissimulate the difficulties that he should have to conquer, but he execrated those who were timorous and always tried to put confidence into those who surrounded him. but, singular phenomenon, he ended by deceiving himself and, at certain times, it would not have been easy to prove to him that the st. gothard was not the most easy undertaking in the world. those who have lived around him know the jokes that he sometimes made at the expense of poor gothard, which paid him back with interest, however, and did not allow itself to be pierced so easy after all. such confidence as existed in the first years, however, was not to exist for ever. the tunnel advanced, the heading deepened, but at the price of what troubles, and especially of how many expenses! day by day one could soon count the probable deficit in the affair and the silent partners began to get a glimpse of the loss of the eight millions of securities that had had to be deposited with the swiss federal council. for favre personally the failure of the enterprise would have been ruin for his fortune was not so large as has been stated. to fears which favre possessed more on account of the associates that he had engaged in the enterprise than for himself, came to join themselves those troubles with the germans that he had spoken to me about on the first day. the st. gothard company, whose troubles are so celebrated, and whose inactivity lasted until the reconstruction of the affair, was seemingly undertaking to make favre, who was directing the only work then in activity, bear all the insults that it had itself had to endure. and yet, amid these multiple cares, the contractor of the tunnel did not allow himself to become disheartened. constantly at the breach he lived at his works, going from the gigantic adit of goschenen to the inundated one of anolo, constantly on the mountain, having no heed of the icy and perilous crossing, and passing days in the torrential rain that was flooding the tunnel. who of us does not picture him in mind as he reached the inn at night, with his high boots still soaking wet, and his gray beard full of icicles to take his accustomed seat at the table, and, between courses, to tell some story full of mirth, some joke from the other works whence he had come, which made us laugh immoderately, and brought a smile to the faces of the german engineers. it is a singular coincidence that this confidence in his own work, despite all the struggles borne, was shared likewise by another man than favre--by germano sommeiller, the creator of the mont cenis tunnel. when the work of the first piercing of the alps was yet in the period of attacks and incredulity, sommeiller wrote his brother the following letter: "always keep me posted my dear leander, as to what the laughers are saying and remember the proverb that 'he will laugh well who laughs last!' the majority of the people, even engineers, are rubbing their hands in expectation of the colossal fiasco that awaits us, and it is for that that the envious keep somewhat silent. i will predict to you that as soon as success is assured everybody will mount to the house tops and say 'i told you so! it was an idea of my own!' what great geniuses are going to spring from the earth! i am in haste, so adieu, courage, energy, silence and especially cheerfulness! and especially cheerfulness!" perhaps this cheerfulness of strong minds is the invincible weapon of those who, like sommeiller and favre, fight against apathy or the bad faith of their adversaries! like favre however sommeiller had not the pleasure of being present at the consecration of his glory, for at the mont cenis banquet as at the st. gothard the place reserved for the creator of the great work was empty. as disastrous as was the enterprise from a financial point of view what a triumph for favre would have been the day on which he traversed from one end to the other that kilometers of tunnel that he had walked over step by step since the first blow of the pick had struck the rock of the st. gothard! but such a satisfaction was not to be reserved for him. suddenly, on the th of july, , less than seven years after the beginning of the work, and six months before the meeting of the adits, in the course of one of his visits to the tunnel favre was carried off by the rupture of a blood vessel. a year before that epoch, i had left the enterprise, favre having confided to me the general supervision over the manufacture of dynamite that he had undertaken at varallo pombia for the needs of his tunnel, but my friend m. stockalper, engineer in chief of the goschenen section, who accompanied favre on his fatal subterranean excursion, has many a time recounted to me the sad details of his sudden death. for months before it must be said favre had been growing old. the man of broad shoulders and with head covered with thick hair in which here and there a few silver threads showed themselves, and who was as straight as at the age of twenty years, had begun to stoop, his hair had whitened and his face had assumed an expression of sadness that it was difficult for him to conceal. as powerful as it was this character had been subjugated. the transformation had not escaped me. often during the days that we passed together he complained of a dizziness that became more and more frequent. we all saw him rapidly growing old. on the th of july, , he had entered the tunnel with one of his friends, a french engineer who had come to visit the work, accompanied by m. stockalper. up to the end of the adit he had complained of nothing, but, according to his habit, went along examining the timbers, stopping at different points to give instructions, and making now and then a sally at his friend, who was unused to the smell of dynamite. in returning he began to complain of internal pains. "my dear stockalper," said he, "take my lamp, i will join you." at the end of ten minutes not seeing him return, m. stockalper exclaimed, "well! m. favre, are you coming?" no answer. the visitor and engineer retraced their steps, and when they reached favre he was leaning against the rocks with his head resting upon his breast. his heart had already ceased to beat. a train loaded with excavated rock was passing and on this was laid the already stiff body of him who had struggled up to his last breath to execute a work all science and labor. a glorious end, if ever there was one! favre died in the full plenitude of his forces at less than fifty four years of age, and i can say, without fear of contradiction, that he was universally and sincerely regretted by all those who had worked at his side. still at the present time when a few of us old colleagues of goschenen, airolo or altorf meet, it is not without emotion that we recall the old days, the joyful reunions at which he cheered the whole table with his broad and genial laugh.--_maxime helene, in la nature._ * * * * * the new harbor of vera cruz. besides the enormous engineering work of rendering navigable one of the mouths of the mississippi delta, and the continuous labor of developing the more original and still bolder project for an isthmian ship railway, mr. james b. eads has been engaged in the design of new and extensive harbor works at vera cruz, which, when completed, will secure for that city a commodious and secure port. the accompanying plan shows the natural features of the locality, as well as the new works. the harbor is formed by the coast line from the punta de la caleta to the punta de hornos, and by la gallega reef. from the first named point a coral reef, nearly dry at low water, extends out about yards into the gulf, and a similar one of about the same length runs out from the punta de hornos. between these is a bay , meters wide, and at its northwest end lies the city of vera cruz. the bay is partly inclosed by an island or reef--la gallega--which, on the harbor front, has a length of , meters. beyond this, and to the southeast, is another small island--the lavendera reef. between the end of this reef and that projecting from the punta de hornos is meters wide. as will be seen from the plan the natural harbor is exposed to the gale from the north and northwest, while the formation affords general protection from the northeast and southeast thanks to five large coral reefs. not unfrequently, however, heavy seas sweep through the wide channels between these small islands interfering seriously with vessels lying alongside the present limited wharfage. northeast, la gallega and gallaguilla reefs run northward from the harbor for , meters and these with the main coast line, form a bay exposed to the full fury of the winds from the north, and when northern winds prevail rough water is driven through the passage between la gallega and caleta reefs with great violence, and sets up a rapid and dangerous current into the harbor. [illustration: new harbor at vera cruz.] from the foregoing it will be seen that, while presenting some advantages, the natural harbor of vera cruz possesses many drawbacks and dangers which the design of mr. eads will completely remove. the leading features of the works about to be carried out are indicated on the plan. they comprise . the construction of a sea wall between la gallega and the lavendera reefs, with an extension over the latter. . the construction of a sea wall from punta de la caleta to la gallega. this part of the work will be begun after the completion of the first wall to a height of at least ft. above low water. . a dike connecting the northern ends of the first two dikes with each other, and stretching across the southern part of la gallega, to prevent the seas which sometimes break over this reef from entering the harbor. the wall between la gallega and lavendera will not only cut off the rough water during northerly gales, but will also effectually prevent the deposition of sand in the harbor, because the through passage to the northwest will be stopped. passages closed by sluice gates will be formed through this wall at about low water level, so that at any time the harbor may be flushed out and stagnation prevented. . after the construction of the inclosing walls the harbor will be dredged out and cleared of coral to a depth of ft. below low water. . following these works of primary importance comes the construction of a wooden roadway from the hornos reef to the northwestern dike. this roadway will form the south front of the harbor, and the excavated material will be deposited on the space between the roadway and the existing bottom, so as ultimately to make it a permanent work with a masonry retaining wall fronting the harbor. the land between the roadway and the city would also be reclaimed to the extent of more than , square yards. . the construction of wooden piers at right angles to the roadway, which would be extended to run around the harbor as trade required it, for ships to be alongside for loading and unloading. the construction of these short piers would be similar to those used in new york and other united states ports, and they might afterward be replaced by masonry if the increase in trade justified so large an expenditure. . the erection of a lighthouse, at or near the eastern end of the lavendera sea wall of a second on the eastern side of la gallaguilla reef, and of another on the west side of la blanquilla reef. these houses will be furnished with distinctive signals to enable steamers running in before another to run with safety between la gallaguilla and la blanquilla as soon as the lavendera light is seen between the other two. the width of deep water at the entrance between the lavendera and hornos reefs will be , ft. the estimated cost of these extensive works is ten millions of dollars, a large sum for the mexican republic to expend in harbor improvements at one port but it will doubtless be found a profitable investment as it will tend greatly to promote trade, and so increase indefinitely the commerce of the port. mr. eads' plan having been approved by the mexican government the work was formally commenced on the th of last august. plans were also furnished by him at the request of the government, for deepening the mouth of the panuco river upon which is located the city of tampico, the gulf terminus of the mexican central railway system.--_engineering._ * * * * * cost of power to make flour. the following estimate of the cost of the power required to manufacture a barrel of flour is taken from the _miller_. the calculation would hardly hold good in this country owing to difference in cost of fuel attendance etc., but is nevertheless of interest. "the cost of a steam motor per stone ( lb.) sack of flour depends entirely on local circumstances. it depends first, on the amount of power expended in the production of a sack of flour, that is on its mode of manufacture, and it depends, secondly, on the cost of the necessary amount of power, that is, on the cost of fuel burned per horse power the average consumption of coal of first class steam engines may be taken at lb. per hour per indicated horse power. "supposing a mill with six pairs of stones, two pairs of porcelain roller mills, and the necessary dressing, purifying, and wheat cleaning machinery to require a steam motor of indicated horse power to drive it, then the average consumption of fuel in this mill would be lb. of coal per hour. such a mill working day and night will turn out about sacks of flour per week of, say, hours, so that x = , lb. of coal would be required to manufacture sacks of flour. the cost of this quantity of coal may be taken at, say, £ (about $ . ), and for cost of attending engine and boiler, cost of oil, etc., another £ (about $ . ) per week may be added; so that, in this case, the manufacture of sacks of flour would cause an expenditure of £ ($ . ) for the steam motor. therefore the cost of the steam motor per -stone sack of flour may be taken at d. (about cents) per sack, if an improved low grinding system is used. "in this case it is supposed that about per cent. of flour is obtained in the first run, leaving about per cent. of middlings and about per cent. of bran, which is finished in a bran duster. the middlings are purified, ground over one pair of middling stones, then dressed through a centrifugal and the tailings of the latter are passed over one of the porcelain roller mills, whereas the other porcelain roller mill treats the second quality of middlings coming from the purifier. the products from the two porcelain roller mills are dressed through a second centrifugal, and the whole flour is mixed into one straight grade. four pairs of stones are supposed to work on wheat, one on middlings, and one pair is sharpening. the first run is supposed to be dressed through two long silk reels. of course, not every steam motor has so low a consumption of coal as two pounds per hour per horse power; it often amounts to three, four, and five pounds per hour. in that case, of course, the cost of steam power per sack is much greater than d. per sack. a greater number of breaks does not necessarily increase the cost of steam power per sack of flour. although more machines may be employed, each of them may require less horse power; so that the total amount of power required for manufacturing an equal amount of flour may not be greater in the case of gradual reduction. "as, however, the cost of maintenance may be slightly greater in the latter case, on account of a greater number of more elaborate machines, the cost of manufacturing a sack of flour may be a little greater when gradual reduction is employed, taking into account the total expenses of the mill and interest on the capital employed. "water motors are generally a much cheaper source of energy than steam motors, but they are not so reliable and constant as the latter. the very irregular supply of water sometimes causes stoppages of the mill, and often a reserve steam engine has to be provided in order to assist the water motor when the quantity of water decreases during the summer months. wind motors were formerly extensively used for milling purposes, but they are now gradually disappearing. they are too irregular and unreliable, although they utilize a very cheap motive power. it is not advantageous to expend a large amount of capital for a mill which often is unable to work at the very time when there are favorable opportunities for doing profitable business. animal motors are too dear. they are only suitable for driving very small mills in out of the way localities." * * * * * driving gear mechanism for lift hammers. a very interesting system of driving gear for lift hammers was applied in an apparatus exhibited at frankfort in by mr. meier of herzen. the arrangement of the mechanism is shown in figs. and . in the upper part of the hammer-frame there is a shaft which is possessed of a continuous rotary motion, and, with it, there is connected by a friction coupling a drum that receives the belt from which is suspended the hammer. in the apparatus exhibited, the mechanism is so arranged that the hammer must always follow the motion of the controlling lever in the same direction; but a system may likewise be adopted such that the hammer shall continue to operate automatically, when and so long as a lever prepared for such purpose is lowered. _ab_ is the shaft having a continuous rotary motion, and upon which are fixed the pulley, c, the fly-wheel, d, and the friction-disk, e. upon one of the extremities of the driving shaft is fixed an elongated sleeve, formed of the drum, g, and of the screw, f, carried by the nut, h. this latter is supported in the frame in such a way that it cannot turn, but can move easily in the direction of the axis. such motion may be produced by the spring, i, and its extent is such that the drum, g, is brought in contact with the friction-disk, e. the hand-lever, k, rod, l, and bent lever, m, serve to bring about a motion in the opposite direction, and which disengages the drum, g, from the disk, e, and lets the hammer fall; the drum being then able to turn freely. if the lever, k, be afterward raised again, the spring, i, will act anew and couple the drum with the driving-shaft, so that the hammer will be lifted. in this rotary motion the screw, f, turns or re-enters into its nut, which it displaces toward the left, since it cannot itself move in that direction until the rectilinear motion be wiped out, and the power of the spring be thus overcome. at the same moment, the screw should naturally also make this rectilinear movement forward, that is to say, the coupling would be disengaged, if, at the least lateral motion toward the right, the spring, i, did not push the system toward the left. there is thus produced a state of equilibrium such that there is just enough friction between the disk, e, and the drum, g, to keep the hammer at rest and suspended. through the action of an external force which lowers the lever, k, the hammer at once falls, and the screw issues anew from its nut and brings the parts into their former positions. [illustration: meier's driving gear mechanism for lift hammers.] * * * * * de junker & ruh's machine for cutting annular wheels. the machine shown in figs. , , and has been devised by messrs. junker & ruh, of carlsruhe, for cutting internally-toothed gear-wheels. the progress of the work is such that the wheel is pushed toward the tool by a piece, n, provided with a curve guide, and that the tool is raised and separated from the wheel after a tooth has been cut, in order to allow the wheel to revolve one division further. the tool is placed in a support, b, which is fixed to the upright, d, in such away that it may revolve; and this support is connected to the frame, a, of the machine. a strong flat spring, f, constantly presses the tool-carrier, b, toward the upright, d, as much as the screw, g, will permit; and this pressure and the tension of the belt draw the tool downward. the screws, g, determine the depth of the cut, and compensate for the differences in the diameter of the tool. [illustration: machine for cutting annular wheels.] the wheels to be cut are set by pressure into a wrought iron ring, with which they are placed in a sleeve or support, h. the connection between the two is assured by means of a nut, c. the axle of the support, h, is held in the upright of the carriage, k, which receives from a piece, l, placed on the driving-shaft, n, a slow forward motion toward the tool, and a rapid motion backward. the trajectory curve or groove of special form of the piece, l, in which moves the conducting roller, o, of the carriage, is not closed everywhere on the two sides, in that the guides that limit it extend only on the part strictly necessary. this arrangement permits of the roller being made to leave the trajectory in order that the carriage may be drawn back to a sufficient distance from the tool when the wheel is finished, so as to replace the latter by another. one hollow is cut during each forward travel of the carriage; and, when such travel is finished, a cam-disk, p, placed on the shaft, n, lifts the tool-carrier, b, and thus draws the cutting-tool out of the hollow cut by it, so that the carriage cam can then move back without restraint. in the interim, the sleeve, h, which supports the wheel, revolves one tooth through the following arrangement: on the axis, e, of this sleeve there are two ratchet-wheels, r and s, the number of whose teeth is equal to that of the teeth to be cut in the wheel. the wheel, r, produces the rotation of the sleeve, h, and the wheel, s, keeps the shaft stationary during the operation. the two wheels are set in motion by a lever, t, or by its click, this lever being raised at the desired moment on the free extremity of the driving shaft, n, by a wedge, u. the short arm of the lever, t, engages, through its point of appropriate shape, with the teeth of the wheel, s, so as to keep this latter stationary while the tool is cutting out the interspace between the teeth. when the lever, t, is raised, this point is at first disengaged from the wheel, s; and the raising of the lever being prolonged, the button, i, places itself against the upper curve of the slot in the lever, q, and raises that likewise. q is connected with the lever, v, which revolves about the axis, e, and v carries the click, w, so that when the lever, v, is raised, the wheel, r, turns forward by one tooth. when the lever, t, is lowered, as the wedge, u, turns more, its click holds the wheel, s, stationary. this series of operations is repeated until the last interspace between the teeth has been cut, when the machine stops automatically as follows: a cam of the disk, a, which receives from the shaft, n, through cone-wheels, a motion corresponding to that of the wheels, r and s, abuts against the two-armed lever, z, and this latter then disengages the rod, y, so that the weight, g, can move the fork, b, in such a way that the belt shall pass from the fast to the loose pulley. motion is communicated to the machine as a whole by the shaft, c, which is provided with a fast and loose pulley. as shown in the engraving, the pulley, d, moves the tool, and the pulley, e, causes the revolution of the shaft, n, through a helicoidal gearing, f. the construction of the tool carrier is represented in detail in fig. . the cutting tool, f, rests on a sleeve forming part of the pulley, r , against which it is pressed by a nut, while its position is fixed by a key. the axle, s , of the tool is held in two boxes, in which it is fixed by screws. in order that the tool may be placed exactly in the axis of the wheel to be toothed, and that also the play produced by lateral wear of the pulley, r , may be compensated for, two screws, r , are arranged on the sides. all rotation of the shaft, s , is prevented by a screw, o, which traverses the cast iron stirrup, c, and the steel axle box. * * * * * recent hydraulic experiments. at a late meeting of the institution of civil engineers, the paper read was on "recent hydraulic experiments," by major allan cunningham, r.e. this paper was mainly a general account of some extensive experiments on the flow of water in the ganges canal, lasting over four years-- - . their principal object was to find a good mode of discharge measurements for large canals, and to test existing formulæ. there are about , velocity, and surface-slope measurements, besides many special experiments. the ganges canal, from its great size, from the variety of its branches abounding in long straight reaches, and from the power of control over the water in it, was eminently suited for such experiments. an important feature was the great range of conditions, and, therefore, also of results obtained. thus the chief work was done at thirteen sites in brickwork and in earth, some being rectangular and others trapezoidal, and varying from ft. to ft. in breadth, and from ft. to in. in depth, with surface-slopes from to per million, velocities from . ft. to . ft. per second, and discharges from , to cubic feet per second. for all systematic velocity measurements, floats were exclusively used, viz., surface floats, double floats, and loaded rods. their advantages and disadvantages had been fully discussed in the detailed treatise "roorkee hydraulic experiments"-- . they measured only "forward velocity," the practically useful part of the actual velocity. the motion of water, even when tranquil to the eye, was found to be technically "unsteady;" it was inferred that there is no definite velocity at any point, and that the velocity varies everywhere largely, both in direction and in magnitude. the average of, say, fifty forward velocity measurements at any one point was pretty constant, so that there must be probably average steady motion. hence average forward velocity measurements would be the only ones of much practical use. to obtain these would be tedious and costly, and special arrangements would be required to obviate the effects of a change in the state of water, which often occurred in a long experiment, as when velocities at many points were wanted. as to surface-slope its measurement--from nearly trials--was found to be such a delicate operation that the result would be of doubtful utility. this would affect the application of all formulas into which it entered. the water surface was ascertained, on the average of its oscillations, to be sensibly level across, not convex, as supposed by some writers. there were sets of vertical velocity measurements combined into forty-six series. the forty-six average curves were all very flat and convex down stream--except near an irregular bank--and were approximately parabolas with horizontal axes; the data determined the parameters only very roughly; the maximum velocity line was usually below the service, and sank in a rectangular channel, from the center outward down to about mid-depth near the banks. its depression seemed not to depend on the depth, slope, velocity, or wind; probably the air itself, being a continuous source of surface retardation, would permanently depress the maximum velocity, while wind failed to effect this, owing to its short duration. on any vertical the mid-depth velocity was greater than the mean, and the bed velocity was the least. the details showed that the mid-depth velocity was nearly as variable from instant to instant as any other, instead of being nearly constant, as suggested by the mississippi experimenters. the measurement of the mean velocity past a vertical was thought to be of fundamental importance. loaded rods seemed by far the best for both accuracy and convenience in depths under ft. they should be immersed only . of the full depth. the chief objection to their use, that--from not dipping into the slack water near the bed--they moved too quickly, was thus for the first time removed. a double float with two similar sub-floats at depths of . and . of the full depth would also give this mean with more accuracy and convenience than any instrument of its class; this instrument is new. measurement of the velocity at five eighths depth would also afford a fair approximation. one hundred and fourteen average transverse velocity curves were prepared from separate curves. these average curves were all very flat, and were convex down stream--over a level or concave bed--and nearly symmetric in a symmetric section. the velocity was greatest near the center, or deepest channel, decreased very slowly at first toward both banks, more rapidly with approach to the banks or with shallowing of the depth, very rapidly close to the banks, and was very small at the edges, possibly zero. the figure of the curve was found to be determined by the figure of the bed, a convexity in the bed producing a concavity in the curve and _vice versa_, and more markedly in shallow than in deep water. curves on the same transversal, at the same site, and with similar conditions, but differing in general velocity, were nearly parallel projections. at the edges there was a strong transverse surface flow from the edge toward mid-channel, decreasing rapidly with distance from the edge. the discussion showed that it was almost hopeless to seek the geometric figure of the curves from mere experiment. five hundred and eighty-one cubic discharges were measured under very varied conditions. the process adopted contained three steps: ( ) sounding along about fifteen float courses, scattered across the site in eight cross sections; time, say four hours. ( ) measurement of the mean velocities through the full depths in those float courses, each thrice repeated; time, say four hours. ( ) computation, say two hours. this process was direct and wholly experimental; each step was done in a time which gave some chance of a constant state of water. from an extended comparison of all results under similar conditions, it appeared that the above process yielded, under favorable circumstances, results not likely to differ more than per cent. the sequel showed that in a channel with variable regimen, a discharge table for a given site must be of at least double entry, as dependent on the local gauge-reading, and on the velocity or surface-slope. special attention was paid to rapid approximations to mean sectional velocity. the mean velocity past the central vertical, the central surface velocity, and chézy's quasi-velocity--i.e., x sqrt (r x s) where r = the hydraulic mean depth, and s = surface slope--were tried in detail; thus , , and average values thereof respectively were taken from , , and detail values. the ratios of these three velocities to the mean velocity were taken out, and compared in detail with bazin's and cutter's coefficients. other formulæ were contrasted also in slight detail. kutter's alone seemed to be of general applicability; when the surface slope measurement is good, and the rugosity coefficient known for the site--both doubtful matters--it would probably give results within ½ per cent. of error. improvement in formulæ could at present be obtained only by increased complexity, and the tentative research would be excessively laborious. now the first two ratios varied far less than the third; thus their use would probably involve less error than the third, or approximation would be more likely from direct velocity measurement than from any use of surface slope. the connection between velocities was probably a closer one than between velocity and slope; the former being perhaps only a geometric, and the latter a physical one. the mean velocity past the central vertical was recommended for use, as not being affected by wind; the reduction coefficient could at present only be found by special experiment for each site. three current meters were tried for some time with a special lift, contrived to grip the meter firmly parallel to the current axis, so as to register only forward velocity, and with a nearly rigid gearing wire. no useful general results were obtained. ninety specimens of silt were collected, but no connection could be traced between silt and velocity; it seemed that the silt at any point varied greatly from instant to instant, and that the quantity depended not on the mean velocity, but probably on the silt in the supply water. forty measurements of the evaporation from the canal surface were made in a floating pan, during twenty five months. the average daily evaporation was only about / in. the smallness of this result seemed to be due to the coldness of the water--only deg. in may, with deg. in the sun and deg. in shade. lastly, it must suffice to say that great care was taken to insure accuracy in both fieldwork and computation. * * * * * the germ. by arthur atkins. there seems to have sprung up within a few mouths a tendency to revive the discussion on that hackneyed question, "shall the germ be retained in the flour?" this question has been more than once answered in the negative by both scientific and practical men, but recently certain prominent persons have come to the conclusion that every one has been wrong on this point, and the miller should by all means retain the germ. now the nutritive value of the germ cannot be disputed, but there are two circumstances which condemn it us an ingredient of flour. the first is that the albuminoids which it contains are largely soluble, and this means that good light bread from germy flour is impossible. i have not time to go into a detailed explanation of the chemical reasons for this, but they may be found in a series of articles which appeared in _the milling world_ about a year ago. in the next place, the oil contained in the germ not only discolors the flour, but seriously interferes with its keeping qualities. now color is only a matter of taste, and if that were the only objection to the germ, it might be admitted, but we certainly do not want anything in our flour to interfere with making light, sweet bread, and will render it more liable to spoil. if our scientists can discover some method of obviating these objections, it will then be time enough to talk about retaining the germ. meanwhile millers know that germy flour is low priced flour, and they are not very likely to reduce their profits by retaining the germ.--_milling world._ * * * * * wheat tests. there was considerable complaint last season, on the part of wheat raisers in sections tributary to minneapolis, on account of the rigid standard of grading adopted by the millers of that city. it was asserted that the differentiation of prices between the grades was unjustly great and out of proportion to the actual difference of value. in order to ascertain whether this was the case or not, the farmers' association of blue earth county, minn., decided to have samples of each grade analyzed by a competent chemist in order to determine their relative value. accordingly specimens were secured, certified to by the agent of the millers' association of minneapolis, and sent to the university of minnesota for analysis. the analysis was conducted by prof. wm. a. noyes, ph.d., an experienced chemist, who has recently reported as follows: "the analyses of wheat given below were undertaken for the purpose of determining whether the millers' grades of wheat correspond to an actual difference in the chemical character of the wheat. for this purpose samples of wheat were secured, which were inspected and certified to by m. w. trexa on april th of this year. the inspection cards contained no statement except the grade of the wheat and the weight per bushel, but the samples were all of fife, for the purpose of a better comparison. the analyses of the wheat were made during october in this laboratory. in each case the wheat was carefully separated from any foreign substances before analysis. the results of analysis were as follows: grade grade grade no. . no. . no. . weight per bushel.................. lb. ½ lb. lb. grains to weigh grains.......... per ct. per ct. per ct. foreign matter (seeds, etc.)....... . . . nitrogen........................... . . . phosphorus......................... . . . water.............................. . . . ash................................ . . . albuminoids (nitrogen multiplied by ¼)........................... . . . cellulose.......................... . . . starch, sugar, fat, etc............ . . . "the analyses require but little comment. the only substances in which there is evident connection between the results of analysis and the grades of wheat are the cellulose, ash, and phosphorus. as regards the last substance, grades two and three seem to have the greatest food value. but it seems quite probable from the results that greater difference would be found between different varieties of wheat of the same kind than is shown here between different grades of the same variety of wheat. however, it does not necessarily follow from this that the different grades of wheat are of nearly equal value to the miller for the purpose of making flour. that is a question which can be best answered by determining accurately the amount and character of the flour which can be made from each grade of wheat. if possible, the investigation will be continued in that direction." as prof. noyes justly remarks, the value of the different grades of wheat can best be determined by a comparison of the results of reducing them to flour, but an intelligent study of the table given above would of itself be sufficient to indicate the justness of the grading. in the first place, even were the percentages of the different components exactly the same in each grade, still the difference in weight would of itself be sufficient to justify a marked difference in price. this requires no proof, for, other things being equal, fifty-nine pounds is worth more than fifty-five pounds. again, the figures show that no. contained nearly four times as much foreign matter as no. . millers certainly should not be expected to pay for foreign seeds or other substances valueless for their purpose, at the price of wheat. finally, if the analysis proves anything, it proves that the lower grades contain a decidedly larger percentage of components which it is generally agreed, whether directly or the reverse, ought not to be incorporated with the flour, and are, therefore, of comparatively little value to the miller. this is shown by the relative amounts of cellulose, ash, and phosphorus present. cellulose, as every one knows, is the woody, indigestible substance which is found in the bran, and the greater the amount of cellulose, the heavier will be the bran in proportion to the flour producing elements. according to the figures presented, no. contained nearly one-quarter more cellulose than no. , while the amount in no. was slightly less than in no. . the ash, too, which represents the mineral constituents of the wheat, is directly dependent upon the quantity of bran. here, too, the lowest grade is shown to yield about one-quarter more than the highest. the larger percentage of phosphorus in the lower grades is suggested by the analyst to indicate their greater food value in this respect. so it would, were we in the habit of boiling our wheat and heating it whole, or of using "whole wheat meal." but, fortunately or unfortunately, the bread reformers have not yet succeeded in inoculating any considerable portion of the community with their doctrines, and hence the actual food value of any sample of wheat must be ascertained, not directly from the composition of the wheat, but from the composition of the flour made therefrom. now, as already stated, phosphorus, like the other mineral components, is found almost entirely in the bran. its presence in greater quantity, therefore, simply adds to the testimony that a larger proportion of the low grade wheat must be rejected than of the higher grade. it should be evident to the complaining farmers that the millers were in the right of the question, on this occasion at least. it is expected that further analysis will be made, this time of the flour made from the different grades of wheat. if these investigations be properly conducted, we have no doubt that they will simply confirm the evidence of the wheat tests. a chemical analysis alone, however, will not be sufficient. the quantity of flour obtained from a given amount of wheat must also be ascertained and its quality further tested by means best known to millers, as regards "doughing-up," keeping qualities, color, etc. and then the result can be no less than to show what millers already knew--that the best quality of flour, commanding the top prices in the market, cannot be obtained from an inferior quality of wheat.--_milling world._ * * * * * apparatus for printing by the blue process.[ ] [footnote : read june , , before the boston society of civil engineers.] by channing whitaker. the blue process is well known to the members of the society, and i need not take time to describe it; but with the ordinary blue process printing frame the results are sometimes unsatisfactory, and now that the process has come to be so commonly used i have thought that an account of an inexpensive but efficient printing frame would be of interest. the essential parts of the apparatus are its frame, its glass, its pad or cushion, its clamps, and the mechanism by which the surface of the glass can easily be made to take a position that is square with the direction of the sun's rays. _the blue process printing frame in common use.--its defects._--the pad of the apparatus in common use consists of several thicknesses of blanketing stretched upon a back board. the sensitized paper and the negative are placed between the pad and the plate glass, and the whole is squeezed together by pressure applied at the periphery of the glass and of the back-board. both the glass and the back-board spring under the pressure, and it results that the sensitized paper is not so severely pressed against the negative near the center of the glass as it is near the edges. if at any point the sensitized paper is not pressed hard up against the negative, a bluish tinge will appear where a white line or surface was expected. with an efficient printing frame and suitable negatives, these blue lines will never appear, and it was to prevent the production of defective work that i undertook to improve the pad of the printing frame. _the printing frame used in ordinary photography._--very naturally, i first examined the printing frame used in ordinary photography. this frame is extremely simple, and is very well adapted to its use. it is, undoubtedly, the best frame for blue process printing, when the area of the glass is not too large. the glass is set in an ordinary wooden frame, while the back-board is stiff and divided into two parts. a flat, bow-shaped spring is attached by a pivot to the center of each half of the back-board. the two halves of the back-board are hinged together by ordinary butts. four lugs are fastened to the back of the frame, and, when the back-board is placed in position, the springs may be swung around, parallel to the line of the hinges, and pressed under the lugs, so that the back of the back-board is pressed most severely at the center of each half, while the glass is prevented from springing away from the back-board by the resistance of the frame at its edges. unless the frame is remarkably stiff, it will resist the springing of the glass more perfectly in the neighborhood of the lugs than elsewhere. it will now be seen that, on account of the manner in which the pressure is applied, the back-board tends to become convex toward the glass, while the adjacent surface of the glass tends to become concave toward the back-board; and that with such a frame, the pressure upon all parts of the sensitized paper is more nearly uniform than when the pressure is applied in the manner before described. with a small frame of this description, a piece of ordinary cotton flannel is used between the back-board and the sensitized paper, and, with larger sizes, one or more thicknesses of elastic woolen blanket are substituted for the cotton flannel. there is an advantage in having a hinged back-board like that which has been described, because, when the operator thinks that the exposure to sunlight has been sufficiently prolonged, he can turn down either half of the back and examine the sensitized paper, to see if the process has been carried far enough. if it has not, the back-board can be replaced, and the exposure continued, without any displacement of the sensitized paper with respect to the negative. this is an important advantage. _an efficient blue process frame, for printing from large negatives, or for printing simultaneously from many small ones._--in order to be efficient, such a frame must be capable of keeping the sensitized paper _everywhere tightly pressed against the negative_. again, such a frame, being large, is necessarily somewhat heavy. it should be so mounted that it can be handled with ease; and, in order that it may print quickly, it should be so arranged that it can be turned without delay, at any time, into a position that is square with the direction of the sun's rays. undoubtedly, if a sufficiently thick plate of glass should be used, the ordinary photographic printing frames would answer the purpose, whatever the size, but very thick plate glass is both heavy and expensive. commercial plate glass varies in thickness from one-fourth to three eighths of an inch, and the thicker plates are rather rare. a large plate of it is easily broken by a slight uniformly distributed pressure. but the pressure that is required for the blue process printing, although slight, is much greater than is used in the ordinary photographic process. for the sensitized paper that is used in the blue process printing is, comparatively, very thick and stiff, and it may cockle more or less, while the paper that is used in ordinary photography is thin and does not cockle. now, it is easy to see that a pressure severe enough to flatten all cockles must be had at every part of the sensitized paper, and that, if the comparatively thin, inexpensive, light weight, commercial plate glass is to be used, it is desirable to have the pressure _nowhere much greater than is needed for that purpose_, lest the fragile glass should be fractured by it. in each of my large frames i use the commercial plate glass; instead of the cushion of cotton flannel, or of flannel, i use a cushion filled with air of sufficiently high pressure to flatten all cockles, and to press all parts of the sensitized paper closely against the negative; and instead of the hinged back-board i use a back-board made in one piece and clamped to the frame of the glass at its edges. connected with the cushion is a pressure gauge, and a tube with a cock, for charging the cushion with air from the lungs. experience shows what pressure is necessary with any given paper, and the gauge enables one to know that the pressure is neither deficient nor in excess of that which is safe for the glass. [illustration: plan. cotton flannel removed.] [illustration: section at co.] _the construction of the air-cushion._--the expense of such an air-cushion seemed at first likely to prevent its being used; but a method of construction suggested itself, the expense of which proved to be very slight. the wooden back-board, as constructed, is made in one piece containing no wide cracks. it has laid upon it some thick brown manila paper, the upper surface of which has been previously shellacked to make it entirely air-tight. upon this shellacked surface is laid a single thickness of thin paper of any kind; even newspaper will answer. its object is simply to prevent the sheet rubber, which forms the top of the air-cushion, from sticking to the shellacked paper. the heat of the sun is often sufficient to bring the shellac to a sticky state. it would probably answer as well to shellac the under side of the paper, and to use but one sheet, but i have not tried this plan. around the periphery of the pad, there is laid a piece of rubber gasket about one and a half inches wide, and about one-eighth of an inch thick. in order that the gasket may not be too expensive, it is cut from two strips about three inches wide. one of them is as long as the outside length of the frame, and the other is as long as the outside width of the frame. each of these strips is cut into two l-shaped pieces, an inch and a half in width, with the shorter leg of each l three inches long. when the four pieces are put together a scarf joint is made near each corner, having an inch and one-half lap. it is somewhat difficult to cut such a scarf joint as perfectly as one would wish, and it is best to use rubber cement at the joints. over the gasket is laid a sheet of the thinnest grade of what is called pure rubber or elastic gum. above this, and over the gasket, is placed a single thickness of cotton cloth, of the same dimensions as the gasket, and yet above this are strips of ordinary strap iron, an inch and a half wide and nearly one eighth of an inch thick. these strips are filed square at the ends and butt against each other at right angles. as the edges of the strips are slightly rounded, they are filed away sufficiently to form good joints wherever the others butt against them. the whole combination is bound together by ordinary stove bolts, one quarter of an inch in diameter, placed near the center of the width of the iron strips, and at a distance apart of about two and one-half inches. their heads are countersunk into the strap iron. in making the holes for the stove bolts through the thin rubber, care should be taken to make them sufficiently large to enable the bolt to pass through without touching the rubber, otherwise the rubber may cling to the bolts, and if they are turned in their holes the rubber may be torn near the bolts and made to leak. a rough washer, under each nut, prevents it from cutting into the back-board. for the purpose of introducing air to, or removing air from, the pad, a three-eighths of an inch lock nut nipple is introduced through the back-board, the shellacked paper, and its thin paper covering. without the back-board a t connects with the nipple. one of its branches leads, by a rubber tube, to the pressure gauge, which is a u-tube of glass containing mercury. the other branch has upon it an ordinary plug cock, and, beyond this, a rubber tube terminating in a glass mouth-piece. when it is desired to inflate the air-cushion, it is only necessary to blow into the mouth-piece. a pressure of one inch of mercury is sufficient for any work that i have yet undertaken. with particularly good paper, a lower pressure is sufficient. upon the top of the pad is laid a piece of common cotton flannel with the nap outward, and with its edges tacked along the under edge of the back-board. the cotton flannel is not drawn tight across the top of the pad. the reason for employing a cotton flannel covering is this: when the sheet rubber has been exposed for a few days to the strong sunlight, it loses its strength and becomes worthless. the cotton flannel is a protection against the destruction of the rubber by the sunlight. i first observed this destruction while experimenting with a cheap and convenient form of gauge. i used, as an inexpensive gauge, an ordinary toy balloon, and i could tell, with sufficient accuracy, how much pressure i had applied, by the swelling of the balloon. this balloon ruptured from some unknown cause, and i made a substitute for it out of a round sheet of thin flat rubber, gathered all around the circumference. i made holes about one-quarter of an inch apart, and passing a string in and out drew it tight upon the outside of a piece of three eighths of an inch pipe, i then wound a string tightly over the rubber, on the pipe, and found the whole to be air-tight. this served me for some time, but one day, on applying the pressure, i found a hole in the balloon which looked as if it had been cut with a very sharp knife. that it had been so cut was not to be imagined, and on further examination i found that the fracture had occured at a line which separated a surface in the strong sunlight from a surface in the shade, at a fold in the rubber. i saw that all of the rubber which had been continuously exposed to the intense sunlight had changed color and had become whiter than before, and that that portion of the balloon had lost its strength. i then returned to the use of the mercury gauge, and took the precaution to cover my pad with cotton flannel, as a protection from the light and from other sources of destruction. this pad is upon the roof of the institute; and is exposed to all weathers. as a protection from the rain and the snow, the whole is covered again with a rubber blanket. it has withstood the exposure perfectly well for a year, without injury. the gauge, made from flat rubber, is altogether so cheap and so convenient that i am now experimenting with one of this description having a black cloth covering upon the outside. the balloon is of spherical shape, the black cloth covering is of cylindrical shape, and i hope that this device will serve every necessary purpose. a sectional view of the air-cushion is offered as a part of this communication. _the frame, which contains the plate glass_, is made of thick board or plank, with the broad side of the board at right angles to the surface of the glass. a rabbet is made for the reception of the glass, and four strips of strap iron, overlapping both the glass, and the wood, and screwed to the wood, keep the glass in position. strips of rubber are interposed between the glass and the wood and between the glass and the iron. the frame is hinged to the back-board by separable hinges, so that the glass can be unhinged from the pad without removing the screws. hooks, such as are used for foundry flasks, connect the frame with the pad upon the opposite side. a frame made in this manner is very stiff and springs but little, and its depth serves an excellent purpose. the air-cushion and the frame are so mounted that they can be easily turned to make the surface of the glass square with the direction of the sun's rays. it is necessary to have a tell tale connected with the apparatus, which will show when the surface of the glass has been thus adjusted. the shadow of the deep frame is an inexpensive tell-tale, and enables the operator to know when the adjustment is right. i have now described, in detail, the construction of the air-cushion with its back-board, as well as that of the frame which holds the plate glass, and i think it will be evident that the first cost of the materials of which they are made is comparatively little, and that the workmanship required to produce it is reduced to a minimum. it will also, i think, be evident that a uniform pressure, of any desired intensity, can be had all over the surface of the sensitized paper for the purpose of securing perfect contact between it and the negative. the blue copies that are taken with this apparatus are entirely free from blue lines when the negatives, chemicals, and paper are good. _the mechanism for adjusting the surface of the glass, until it shall be perpendicular to the direction of the sun's rays._--i have found many uses for the blue copying process in connection with the work of instruction at the massachusetts institute of technology. notes printed by it are far better and less costly than those printed by papyrograph. i will not detain you now with an account of the uses that i have made of it. i will merely say that more than a year ago i found that my frame, which has a glass feet x feet, was wholly inadequate to the work in hand, and i tried to increase the production from it by diminishing the time of printing. the glass of this frame was horizontal, except when one of its ends was tilted off from the slides which guided it when pushed out of the window; and i knew that it took three or four times as long to print when the sun was low as it did when the sun was near the meridian. i made plans for mounting this frame upon a single axis, about which it could be turned after it had been pushed through the window, but i saw that no movement about a single axis would give a satisfactory adjustment for all times of the year, and i considered what arrangement of two axes would permit a rapid and perfect adjustment, at all times, with the least trouble to the operator. it was evident that when the sun was in the equatorial plane, the surface of the glass should contain a line which was parallel to the axis of the earth; and further, that if such a glass was firmly attached to an axis which was parallel to that of the earth, it would fulfill the desired purpose. for the glass, being once in adjustment, is only thrown out of position by the rotation of the earth, and if the glass is rotated sufficiently about its own axis, in a direction opposite to that of the earth, it will retain its adjustment. in order to have the adjustment equally good when the sun was either north or south of the equatorial plane, it was sufficient to mount a secondary axis upon the primary one and at right angles to it. about this the glass could be turned through an angle of ½°, either way, from the position which it should have when the sun was in the equatorial plane. [illustration: blue process printing apparatus.] _the construction of the adjusting mechanism._--i desired to have the mechanism as compact and inexpensive as possible, and to have the frame well balanced about the primary axis, in every position. i also desired to have a rotation of nearly ° about the principal axis. the plan adopted will be most easily understood by referring to the drawing which illustrates it. the axes are composed chiefly of wood. they are built up from strips which are inches × / inch, and from small pieces of inch plank. they are stiffly braced. a pair of ordinary hinges permit the secondary rotation to occur, while a pair of cast iron dowel pins with their sockets, such as are used in foundry flasks, serve as pivots during the primary rotation. _the adjustments._--the adjustment about the secondary axis does not need to be made more frequently than once a week, or once a fortnight. in order to prevent rotation about this axis when in adjustment, two cords lead from points which are beneath the back board, and as far removed from the secondary axis as is convenient. each cord passes forward and backward through four parallel holes in a wooden block which is attached to the primary axis. the cords can be easily slipped in the holes by pulling their loops, but the friction is so great that they cannot be slipped by pulling at either end. it takes about twice as long to make the adjustment as would be necessary if a more expensive device had been used; but this device is at once so cheap, so secure, and has so seldom to be used, that it was thought to be best adapted for the purpose. to prevent rotation from occurring about the primary axis when it is not desired, a bar parallel to the secondary axis is attached by its middle point to the primary axis near one end. a cord passes from either end of this bar through cam shaped clamps, which were originally designed for clamping the cords of curtains with spring fixtures. these clamps are cheap. they are easily and quickly adjusted, and are very secure. the whole apparatus can be located upon the roof of a building, or, if convenient, it can be mounted upon slides, and pushed through an open window when it is to be exposed to the light. if it is to be used upon a roof, a small hut, or shelter of some sort, near by is a great convenience to the operator, particularly in winter. _an inexpensive drying case for use in coating the paper._--when the apparatus is in continuous use, time may be saved by having a convenient arrangement for drying the sheets that have been coated with the sensitizing liquid. i have made an inexpensive drying case which serves the purpose very well. it consists simply of a light-tight rectangular case of drawers. there are twenty-five drawers in all. they are constructed in an inexpensive manner, and are the only parts of the case that are worth describing. they are very shallow, being but - / inches deep, and as it appeared that the principal expense would be for the materials of which the bottoms of the drawers should be composed, it was decided to make the bottoms of cotton cloth. this cloth is stretched upon a frame, the dimensions of which are greater than that of the paper to be dried. the stock of which the frame is made is pine, ¼ inches wide, and three-eighths of an inch thick. the corners are simply mitered together and attached to each other by means of the wire staples that are commonly used for fastening together pages of manuscript, and which are called "novelty staples." eight staples are used at each miter, four above and four below the joint. two of the staples, at the top and near the ends of the joint, are set square across it, and two others, at the top and near the middle of the joint, are placed diagonally across it. the staples at the bottom are similarly placed. the joint is quite firm and strong, and is likely to hold for an indefinite period with fair usage. the cloth, stretched upon the frame, is fastened to it by means of similar staples. a dark colored cloth not transparent to light is to be preferred. a strip of pine, - / inches wide, and three eighths of an inch thick, forms the vertical front of the drawer, and prevents the admission of much light from the front while the sheet is drying. two triangular knee pieces, three-quarters of an inch thick, serve to connect the front board with the frame, and four small screws with a few brads are used in attaching them. the lower edge of the front board drops one-quarter of an inch below the bottom of the drawer. my case stands in a poorly lighted room, and paper dried in this case and removed to a portfolio as soon as it is dry does not seem to be injured by the light that reaches it. with the case in a well lighted room, i should prefer to have outer doors to the case, made of ordinary board six or eight inches wide, hinged to one end, and arranged to swing horizontally across the front of the case. these would more completely prevent the admission of light. the opening of any one of the doors would allow three or four of the drawers to be filled, while the rest of the case would be comparatively dark at the same time.[ ] [footnote : since this paper was read, i have seen in the office of the city engineer of boston a drying case which is similar in some respects to the one that i have devised. it has been longer in use than my own. the drawers are simply the ordinary mosquito netting frames covered with cotton netting. they have no fronts, but a door covers the front of the case, and shuts out the light.] _the portfolio for protecting the sensitized paper from exposure to light._--the sensitized paper is very well protected from exposure to light, if kept in a portfolio or book, the brown paper leaves of which are considerably larger than the sensitized sheets. the sheets may be returned to such a book after exposure, and washed at the convenience of the operator. they can be washed more quickly and perfectly if _two_ water-tanks are provided in which to wash them. a few minutes' soaking will remove nearly all of the sensitizing preparation which has not been fixed by the exposure. if the soaking is too long continued in water that is much discolored by the sensitizing preparation, the sheets become saturated with the diluted preparation, and they may become slightly colored by _after_ exposure. if the first soaking is not too long continued, and if the sheets are transferred at once to a second bath of clean water, which is kept slowly changing from an open faucet, they may remain there until the soluble chemicals have been entirely extracted, and there will be no risk of staining by after exposure. washing in two tanks is of more consequence when the ground is white and the lines blue, than when the ground is blue and the lines white. _the grades of paper that are well adapted for blue process work._--i have tested many grades of paper, to ascertain if they were well adapted for blue process work. some grades of brown manila are very good; others have little specks embedded in their surfaces which refuse to take on a blue tint; still others, when printed upon, have white lines that are wider than the corresponding black lines of the negative. the blue obtained upon bond paper appears to be particularly rich, and the whites remain pure; but bond paper cockles badly, and the cockles remain in the finished print. weston's linen record is an excellent paper. it is strong, cockles but little, and dries very smooth. a paper that is used by allen & rowell, for carbon printing, is comparatively cheap, and is an excellent paper. it is not so stiff as the linen record, and the whites are quite as pure. it does not cockle, neither does it curl while being sensitized. it comes in one hundred pound rolls, and is about thirty inches wide. the best papers are those that are prepared for photographic work. the plain saxe and the plain rives both give excellent results. blue lines on a pure white ground can be obtained on these papers, from photographic negatives, without difficulty. none of the hard papers of good grade require the use of gum in the sensitizing liquid. the liquid penetrates the more porous papers too far when gum is not used, and without it good whites are seldom obtained upon porous paper. _the best chemicals for this work_ are the _recrystallized_ red prussiate of potash and the citrate of iron and ammonia, _which is manufactured by powers & wightman_, of philadelphia. if the red prussiate has not been recrystallized, the whites will be unsatisfactory and the samples of citrates of iron and ammonia which have come to us from other chemists than those named, have all proved unreliable for this process. _the sensitizing liquid.--its proportions._--the blue process was originally introduced from france, by the late mr. a. l. holley. i was indebted to mr. p. barnes, who was with mr. holley at the time, for an early account of it, and i had the first blue process machine that was in use in new england. since , instruction in the use of the blue process has been given to the students of mechanical engineering of the massachusetts institute of technology, and they have caused its introduction into many draughting offices. the proportions of the sensitizing liquid, as originally given me by mr barnes, were as follows: red prussiate of potash............. parts. citrate of iron and ammonia......... parts. gum arabic.......................... part. water.............................. parts. _results of experiments._--in our use, it first appeared that the gum might be omitted from the preparation when sufficiently hard papers were used. next, that a preparation containing red prussiate of potash........ parts, citrate of iron and ammonia.... " water......................... " printed more rapidly. this preparation i continue to use when much time may elapse between sensitizing and printing; but, when the paper is to be printed immediately after sensitizing, i use a larger proportion of citrate of iron and ammonia. before arriving at the conclusion that these proportions were the best to be used, i made a series of purely empirical experiments, beginning with the proportions: red prussiate of potash.......... parts. citrate of iron and ammonia....... part. water............................ parts. and ending with the proportions: red prussiate of potash............... part. citrate of iron and ammonia.......... parts. water................................ " i found the best plan for conducting these experiments to be: to coat a sheet of the paper with a given mixture; to cut the sheet into strips before exposure; to expose all the strips of the sheet, at the same time, to the direct sunlight without an intervening negative; and to withdraw them, one after another, at stated intervals. i found that with each mixture there was a time of exposure which would produce the deepest blue, that with over-exposure the blue gradually turned gray, and that if a curve should be plotted, the abscissas of which should represent the time of exposure, and the ordinates of which should represent the intensity of the blue the curves drawn would have approximately an elliptical form, so that if one knew the exact time of exposure which would give the best result with any mixture, one might deviate two or three minutes either way from that time without producing a noticeable result. i have found that, with the same paper, the same blue results with any good proportions of the chemicals named, provided a sufficient weight of both chemicals is applied to the surface; that an excess of the red prussiate of potash renders the preparation less sensitive to light, and very much lengthens the necessary time of exposure; that the prints are finer with some excess of the red prussiate; that an excess of the citrate of iron and ammonia hastens the time of printing materially; that a greater excess of the citrate causes the whites to become badly stained by the iron, while a still greater excess of the citrate, in a concentrated solution causes the sensitized paper to change without exposure to light, and to produce a redder blue or purple, which does not adhere to the paper, but may be washed off with a sponge. i have found that the cheapest method of reproducing inked drawings that have been made on thick paper is not to trace them, but to print the blues from a photographic glass negative; and also, that the dry plate process is well adapted to such work in offices, when one has become sufficiently experienced. printed matter can also most easily and inexpensively be reproduced by the same means, when a small issue is required on each successive year. for the reproduction of manuscript by the blue process, the best plan that i have found has been to write the manuscript upon the thinnest blue tinted french note-paper, with black opaque ink--the stylographic ink is very good--and, afterward, to dip the paper into melted paraffine, and to dry the paper at the melting temperature. this operation, if cheaply done, requires special apparatus. for positive printing from the glass negative, i use a multiple frame, by the aid of which i can print from negatives at the same time, upon a single sheet of paper. this frame is interchangeable with the one that contains the plate glass. the negatives are so arranged in the frame that the sheets can be cut and bound, as in the ordinary process of book binding. the time required for exposure, when printing from glass negatives, varies with the negative; and, in order to secure satisfactory results with the multiple frame it is necessary to stop the exposure of some, while the exposure of others is continued. i insert wooden or cloth stoppers into the frame for the purpose of stopping the exposure of certain negatives. when paraffined manuscript is to be printed from, i find it convenient to have it written on sheets of small size, and to have these mounted upon an opaque frame of brown manila paper, printing sixteen or more at a time, depending upon the size of the printing frame. many small tracings may be similarly mounted upon a brown paper multiple frame, and may be printed together upon a single sheet. * * * * * spectrum gratings. at a recent meeting of the london physical society, prof. rowland, of baltimore, exhibited a number of his new concave gratings for giving a diffraction spectrum. he explained the theory of their action. gratings can be ruled on any surface, if the lines are at a proper distance apart and of the proper form. the best surface, however, is a cylindrical or spherical one. the gratings are solid slabs of polished speculum metal ruled with lines equidistant by a special machine of prof. rowland's invention. an account of this machine will be published shortly. the number of lines per inch varied in the specimens shown from , to , , but higher numbers can be engraved by the cutting diamond. the author has designed an ingenious mechanical arrangement for keeping the photographic plates in focus. in this way photographs of great distinctness can be obtained. prof. rowland exhibited some inches long, which showed the e line doubled, and the large b group very clearly. lines are divided by this method which have never been divided before, and the work of photographing takes a mere fraction of the time formerly required. a photographic plate sensitive throughout its length is got by means of a mixture of eosene, iodized collodion, and bromized collodion. prof. rowland and captain abney, r.e., are at present engaged in preparing a new map of the whole spectrum with a focus of feet. in reply to mr. hilger, f.r.a.s., the author stated that if the metal is the true speculum metal used by lord rosse, it would stand the effects of climate, he thought; but if too much copper were put in, it might not. in reply to mr. warren de la rue, prof. rowland said that , was the largest number of lines he had yet required to engrave on the metal. prof. guthrie read a letter from captain abney, pointing out that prof. rowland's plates gave clearer spectra than any others; they were free from "ghosts," caused by periodicity in the ruling, and the speculum metal had no particular absorption. prof. dewar, f.r.s., observed that prof. liveing and he had been engaged for three years past in preparing a map of the ultra-violet spectrum, which would soon be published. he considered the concave gratings to make a new departure in the subject, and that they would have greatly facilitated the preparation of his map. * * * * * a new pocket opera glass. [illustration: pocket opera glass.] inasmuch as high power combined with small size is usually required in an opera glass, manufacturers have always striven to unite these two features in their instruments, and have succeeded in producing glasses which, although sufficiently small to be carried in the waistcoat pocket, are nevertheless powerful enough to allow quite distant objects to be clearly distinguished. recently, a parisian optician has succeeded in constructing an instrument of this kind that is somewhat of a novelty in its way, since its mechanism allows it to be closed in such a manner as to take up no more space than a package of cigarettes (fig. .) it is constructed as follows: ab and cd (fig. ) are two metallic tubes, in which slide with slight friction two other tubes. into the upper part of the latter are inserted two hollow elliptical eye-pieces, which move therein with slight friction, and which are united by the two supports tor the wheel, _bb_ (fig. ), and endless screw that serve for focusing the instrument. the eyepieces, tt, are held in the tube by means of two screws, _vv_ (figs. and ), in such a way that they can revolve around the latter as axes. the lenses of the eye-piece are fixed therein by means of a copper ring. the object glasses are placed in the ends of the tubes, ab and cd, at _oo_. when the instrument is closed, it forms a cylinder millimeters in diameter by centimeters in length. to open it, it is grasped by the extremities and drawn apart horizontally so as to bring it into the position shown in fig. . then it is turned over so that the screw, v, points upward, while at the same time the two tubes are pressed gently downward. this causes the eye-pieces to revolve around their axes, _vv_, and brings the two tubes parallel with each other.--_la nature._ * * * * * ancient greek painting. a lecture on ancient greek painting was lately delivered by professor c.t. newton, c.b., at university college, london. the lecturer began by reminding his audience of the course of lectures on greek sculpture, from the earliest times to the roman period, which he completed this year. the main epochs in the history of ancient sculpture had an intimate connection with the general history of the greeks, with their intellectual, political, and social development. we could not profitably study the history of ancient sculpture except as part of the collateral study of ancient life as a whole, nor could we get a clear idea of the history of ancient sculpture without tracing out, so far as our imperfect knowledge permits, the characteristics and successive stages of ancient painting. between these twin sister arts there had been in all times, and especially in greek antiquity, a close sympathy and a reciprocal influence. the method in dealing with the history of greek painting in this course would be similar to that adopted in the course on sculpture. the evidence of ancient authors as to the works and characteristics of greek painters would be first examined, then the extant monuments which illustrate the history of this branch of art would be described. in the case of painting, the extant monuments were few and far between, but we might learn much by the careful study of the mural paintings from the buried campanian cities, pompeii, herculaneum, and those found in the tombs near rome and etruria. the paintings on greek vases would enable us to trace the history of what is called ceramographic art from b.c. for nearly five centuries onward. after noticing the traditions preserved by pliny and others as to the earliest painters, the lecturer passed on to the period after the persian war. polygnotos of thasos was the earliest greek painter of celebrity. he flourished b.c. - . at athens he decorated with paintings the portico called the stoa poikile, the temple of the dioscuri, the temple of theseus, and the pinakotheke on the akropolis. at delphi he painted on the walls of the building called lesche two celebrated pictures, the taking of troy and the descent of ulysses into hades. all these were mural paintings; the subjects were partly mythical, partly historical. thus in the stoa poikile were represented the taking of troy, the battle of theseus with the amazons, the battle of marathon. in the temple of theseus came the battle of the lapiths and centaurs and the battle of the amazons again. in the other two athenian temples he treated mythological subjects. these great public works were executed during the administration of kimon, to whom polygnotos stood in the same relation us phidias did to perikles, the successor of kimon. the paintings in the stoa poikile were executed by polygnotos gratuitously, for which service the athenians rewarded him with the freedom of their city. his greatest and probably his earliest works were the two pictures in the lesche at delphi. of these there was a very full description in pausanias. the building called lesche was thought to have been of elliptical form, with a colonnade on either side, separated by a wall in the middle, and to have been about ft in length. the figures were probably life size. according to the list given by pausanias, there were upward of seventy in each of the two pictures. in that representing the taking of troy polygnotos had brought together many incidents described in the cyclic epics: menelaos agamemnon, ulysses, nestor, neoptolemos, antenor, helen, andromache, kassandra, and many other figures, with which the homeric poems have made us familiar, all appeared united in one skillful composition, arranged in groups. the other picture, the descent of ulysses into hades to interrogate teiresias, might be called a pictorial epic of hades. on one side was the entrance, indicated by charon's boat crossing: the acheron, and the evocation of teiresias by ulysses, besides the punishment of tityos and other wicked men; on the other side were tantalos and sisyphos. between these scenes, on the flanks, were various groups of heroes and heroines from the trojan and other legends. from the remarks of ancient critics, it might be inferred that the genius of polygnotos, like that of giotto, was far in advance of his technical skill. aristotle called him the most ethical of painters, and recommended the young artist to study his works in preference to those of his contemporary pauson, who was ignobly realistic, or those of zeuxis, who had great technical merit, but was deficient in spiritual conception. the course will comprise four more lectures, as follows--november , "greek painters from b.c. to accession of alexander the great b.c. --apollodoros, zeuxis, parrhasios, pamphilos, aristides;" november , "greek painters from age of alexander to augustan age--apelles, protogenes, theon;" december , "pictures on greek fictile vases;" december , "mural paintings from pompeii, herculaneum, and other ancient sites." * * * * * the new iowa state capitol has thus far cost $ , , , and it will require $ , to finish it. it is feet long fron north to south, and measures feet from the sidewalk to the top of the central dome. * * * * * [longman's magazine.] atoms, molecules, and ether waves. by john tyndall, f.r.s. i. man is prone to idealization. he cannot accept as final the phenomena of the sensible world, but looks behind that world into another which rules the sensible one. from this tendency of the human mind, systems of mythology and scientific theories have equally sprung. by the former the experiences of volition, passion, power, and design, manifested among ourselves, were transplanted, with the necessary modifications, into an unseen universe from which the sway and potency of those magnified human qualities were exerted. "in the roar of thunder and in the violence of the storm was felt the presence of a shouter and furious strikers, and out of the rain was created an indra or giver of rain." it is substantially the same with science, the principal force of which is expended in endeavoring to rend the veil which separates the sensible world from an ultra-sensible one. in both cases our materials, drawn from the world of the senses, are modified by the imagination to suit intellectual needs. the "first beginnings" of lucretius were not objects of sense, but they were suggested and illustrated by objects of sense. the idea of atoms proved an early want on the part of minds in pursuit of the knowledge of nature. it has never been relinquished, and in our own day it is growing steadily in power and precision. the union of bodies in fixed and multiple proportions constitutes the basis of modern atomic theory. the same compound retains, for ever, the same elements, in an unalterable ratio. we cannot produce pure water containing one part, by weight, of hydrogen and nine of oxygen, nor can we produce it when the ratio is one to ten; but we can produce it from the ratio of one to eight, and from no other. so also when water is decomposed by the electric current, the proportion, as regards volumes, is as fixed as in the case of weights. two volumes of hydrogen and one of oxygen invariably go the formation of water. number and harmony, as in the pythagorean system, are everywhere dominant in this under-world. following the discovery of fixed proportions we have that of _multiple_ proportions. for the same compound, as above stated, the elementary factors are constant; but one elementary body often unites with another so as to form different compounds. water, for example, is an oxide of hydrogen; but a peroxide of that substance also exists, containing exactly double the quantity of oxygen. nitrogen also unites with oxygen in various ratios, but not in all. the union takes place, not gradually and uniformly, but by steps, a definite weight of matter being added at each step. the larger combining quantities of oxygen are thus multiples of the smaller ones. it is the same with other combinations. we remain thus far in the region of fact: why not rest there? it might as well be asked why we do not, like our poor relations of the woods and forests, rest content with the facts of the sensible world. in virtue of our mental idiosyncrasy, we demand _why_ bodies should combine in multiple proportions, and the outcome and answer of this question is the atomic theory. the definite weights of matter, above referred to, represent the weights of atoms, indivisible by any force which chemistry has hitherto brought to bear upon them. if matter were a _continuum_--if it were not rounded off, so to say, into these discrete atomic masses--the impassable breaches of continuity which the law of multiple proportions reveals, could not be accounted for. these atoms are what maxwell finely calls "the foundation stones of the material universe," which, amid the wreck of composite matter, "remain unbroken and unworn." a group of atoms drawn and held together by what chemists term affinity is called a molecule. the ultimate parts of all compound bodies are molecules. a molecule of water, for example, consists of two atoms of hydrogen, which grasp and are grasped by one atom of oxygen. when water is converted into steam, the distances between the molecules are greatly augmented, but the molecules themselves continue intact. we must not, however, picture the constituent atoms of any molecule as held so rigidly together as to render intestine motion impossible. the interlocked atoms have still liberty of vibration, which may, under certain circumstances, become so intense as to shake the molecule asunder. most molecules--probably all--are wrecked by intense heat, or in other words by intense vibratory motion; and many are wrecked by a very moderate heat of the proper quality. indeed, a weak force, which bears a suitable relation to the constitution of the molecule, can, by timely savings and accumulations, accomplish what a strong force out of relation fails to achieve. we have here a glimpse of the world in which the physical philosopher for the most part resides. science has been defined as "organized common sense;" by whom i have forgotten; but, unless we stretch unduly the definition of common sense, i think it is hardly applicable to this world of molecules. i should be inclined to ascribe the creation of that world to inspiration rather than to what is currently known as common sense. for the natural history sciences the definition may stand--hardly for the physical and mathematical sciences. the sensation of light is produced by a succession of waves which strike the retina in periodic intervals; and such waves, impinging on the molecules of bodies, agitate their constituent atoms. these atoms are so small, and, when grouped to molecules, are so tightly clasped together, that they are capable of tremors equal in rapidity to those of light and radiant heat. to a mind coming freshly to these subjects, the numbers with which scientific men here habitually deal must appear utterly fantastical; and yet, to minds trained in the logic of science, they express most sober and certain truth. the constituent atoms of molecules can vibrate to and fro millions of millions of times in a second. the waves of light and of radiant heat follow each other at similar rates through the luminiferous ether. further, the atoms of different molecules are held together with varying degrees of tightness--they are tuned, as it were, to notes of different pitch. suppose, then, light-waves, or heat-waves, to impinge upon an assemblage of such molecules, what may be expected to occur? the same as what occurs when a piano is opened and sung into. the waves of sound select the strings which respectively respond to them--the strings, that is to say, whose rates of vibration are the same as their own--and of the general series of strings these only sound. the vibratory motion of the voice, imparted first to the air, is here taken up by the strings. it may be regarded as _absorbed_, each string constituting itself thereby a new center of motion. thus also, as regards the tightly locked atoms of molecules on which waves of light or radiant heat impinge. like the waves of sound just adverted to, the waves of ether select those atoms whose periods of vibration synchronize with their own periods of recurrence, and to such atoms deliver up their motion. it is thus that light and radiant heat are absorbed. and here the statement, though elementary, must not be omitted, that the colors of the prismatic spectrum, which are presented in an impure form in the rainbow, are due to different rates of atomic vibration in their source, the sun. from the extreme red to the extreme violet, between which are embraced all colors visible to the human eye, the rapidity of vibration steadily increases, the length of the waves of ether produced by these vibrations diminishing in the same proportion. i say "visible to the human eye," because there may be eyes capable of receiving visual impression from waves which do not affect ours. there is a vast store of rays, or more correctly waves, beyond the red, and also beyond the violet, which are incompetent to excite our vision; so that could the whole length of the spectrum, visible and invisible, be seen by the same eye, its length would be vastly augmented. i have spoken of molecules being wrecked by a moderate amount of heat of the proper quality: let us examine this point for a moment. there is a liquid called nitrite of amyl--frequently administered to patients suffering from heart disease. the liquid is volatile, and its vapor is usually inhaled by the patient. let a quantity of this vapor be introduced into a wide glass tube, and let a concentrated beam of solar light be sent through the tube along its axis. prior to the entry of the beam, the vapor is as invisible as the purest air. when the light enters, a bright cloud is immediately precipitated on the beam. this is entirely due to the waves of light, which wreck the nitrite of amyl molecules, the products of decomposition forming innumerable liquid particles which constitute the cloud. many other gases and vapors are acted upon in a similar manner. now the waves that produce this decomposition are by no means the most powerful of those emitted by the sun. it is, for example, possible to gather up the ultra-red waves into a concentrated beam, and to send it through the vapor, like the beam of light. but, though possessing vastly greater energy than the light waves, they fail to produce decomposition. hence the justification of the statement already made, that a suitable relation must subsist between the molecules and the waves of ether to render the latter effectual. a very impressive illustration of the decomposing power of the waves of light is here purposely chosen; but the processes of photography illustrate the same principle. the photographer, without fear, illuminates his developing room with light transmitted through red or yellow glass; but he dares not use blue glass, for blue light would decompose his chemicals. and yet the waves of red light, measured by the amount of energy which they carry, are immensely more powerful than the waves of blue. the blue rays are usually called chemical rays--a misleading term; for, as draper and others have taught us, the rays that produce the grandest chemical effects in nature, by decomposing the carbonic acid and water which form the nutriment of plants, are not the blue ones. in regard, however, to the salts of silver, and many other compounds, the blue rays are the most effectual. how is it then that weak waves can produce effects which strong waves are incompetent to produce? this is a feature characteristic of periodic motion. in the experiment of singing into an open piano already referred to, it is the accord subsisting between the vibrations of the voice and those of the string that causes the latter to sound. were this accord absent, the intensity of the voice might be quintupled, without producing any response. but when voice and string are identical in pitch, the successive impulses add themselves together, and this addition renders them, in the aggregate, powerful, though individually they may be weak. it some such fashion the periodic strokes of the smaller ether waves accumulate, till the atoms on which their timed impulses impinge are jerked asunder, and what we call chemical decomposition ensues. savart was the first to show the influence of musical sounds upon liquid jets, and i have now to describe an experiment belonging to this class, which bears upon the present question. from a screw-tap in my little alpine kitchen i permitted, an hour ago, a vein of water to descend into a trough, so arranging the flow that the jet was steady and continuous from top to bottom. a slight diminution of the orifice caused the continuous portion of the vein to shorten, the part further down resolving itself into drops. in my experiment, however, the vein, before it broke, was intersected by the bottom of the trough. shouting near the descending jet produced no sensible effect upon it. the higher notes of the voice, however powerful, were also ineffectual. but when the voice was lowered to about vibrations a second, the feeblest utterance of this note sufficed to shorten, by one half, the continuous portion of the jet. the responsive drops ran along the vein, pattered against the trough, and scattered a copious spray round their place of impact. when the note ceased, the continuity and steadiness of the vein were immediately restored. the formation of the drops was here periodic; and when the vibrations of the note accurately synchronized with the periods of the drops, the waves of sound aided what plateau has proved to be the natural tendency of the liquid cylinder to resolve itself into spherules, and virtually decomposed the vein. i have stated, without proof, that where absorption occurs, the motion of the ether-waves is taken up by the constituent atoms of molecules. it is conceivable that the ether-waves, in passing through an assemblage of molecules, might deliver up their motion to each molecule as a whole, leaving the relative positions of the constituent atoms unchanged. but the long series of reactions, represented by the deportment of nitrite of amyl vapor, does not favor this conception; for, were the atoms animated solely by a common motion, the molecules would not be decomposed. the fact of decomposition, then, goes to prove the atoms to be the seat of the absorption. they, in great part, take up the energy of the ether-waves, whereby their union is severed, and the building materials of the molecules are scattered abroad. molecules differ in stability; some of them, though hit by waves of considerable force, and taking up the motions of these waves, nevertheless hold their own with a tenacity which defies decomposition. and here, in passing, i may say that it would give me extreme pleasure to be able to point to my researches in confirmation of the solar theory recently enunciated by my friend the president of the british association. but though the experiments which i have made on the decomposition of vapors by light might be numbered by the thousand, i have, to my regret, encountered no fact which prove that free aqueous vapor is decomposed by the solar rays, or that the sun is reheated by the combination of gases, in the severance of which it had previously sacrificed its heat. ii. the memorable investigations of leslie and rumford, and the subsequent classical reasearches of melloni, dealt, in the main, with the properties of radiant heat; while in my investigations, radiant heat, instead of being regarded as an end, was employed as a means of exploring molecular condition. on this score little could be said until the gaseous form of matter was brought under the dominion of experiment. this was first effected in , when it was proved that gases and vapors, notwithstanding the open door which the distances between their molecules might be supposed to offer to the heat waves, were, in many cases, able effectually to bar their passage. it was then proved that while the elementary gases and their mixtures, including among the latter the earth's atmosphere, were almost as pervious as a vacuum to ordinary radiant heat, the compound gases were one and all absorbers, some of them taking up with intense avidity the motion of the ether-waves. a single illustration will here suffice. let a mixture of hydrogen and nitrogen, in the proportion of three to fourteen by weight, be inclosed in a space through which are passing the heat rays from an ordinary stove. the gaseous mixture offers no measurable impediment to the rays of heat. let the hydrogen and nitrogen now unite to form the compound ammonia. a magical change instantly occurs. the number of atoms present remains unchanged. the transparency of the compound is quite equal to that of the mixture prior to combination. no change is perceptible to the eye, but the keen vision of experiment soon detects the fact that the perfectly transparent and highly attenuated ammonia resembles pitch or lampblack in its behavior to the rays of heat. there is probably boldness, if not rashness, in the attempt to make these ultra-sensible actions generally intelligible, and i may have already transgressed the limits beyond which the writer of a familiar article cannot profitably go. there may, however, be a remnant of readers willing to accompany me, and for their sakes i proceed. a hundred compounds might be named which, like the ammonia, are transparent to light, but more or less opaque--often, indeed, intensely opaque--to the rays of heat from obscure sources. now the difference between these latter rays and the light rays is purely a difference of period of vibration. the vibrations in the case of light are more rapid, and the ether waves which they produce are shorter, than in the case of obscure heat. why, then, should the ultra-red waves be intercepted by bodies like ammonia, while the more rapidly recurrent waves of the whole visible spectrum are allowed free transmission? the answer i hold to be that, by the act of chemical combination, the vibrations of the constituent atoms of the molecules are rendered so sluggish as to synchronize with the motions of the longer waves. they resemble loaded piano strings, or slowly descending water jets, requiring notes of low pitch to set them in motion. the influence of synchronism between the "radiant" and the "absorbent" is well shown by the behavior of carbonic acid gas. to the complex emission from our heated stove, carbonic acid would be one of the most transparent of gases. for such waves olefiant gas, for example, would vastly transcend it in absorbing power. but when we select a radiant with whose waves the atoms of carbonic acid are in accord, the case is entirely altered. such a radiant is found in a carbonic oxide flame, where the radiating body is really hot carbonic acid. to this special radiation carbonic acid is the most opaque of gases. and here we find ourselves face to face with a question of great delicacy and importance. both as a radiator and as an absorber, carbonic acid is, in general, a feeble gas. it is beaten in this respect by chloride of methyl, ethylene, ammonia, sulphurous acid, nitrous oxide, and marsh gas. compared with some of these gases, its behavior, in fact, approaches that of elementary bodies. may it not help to explain their neutrality? the doctrine is now very generally accepted that atoms of the same kind may, like atoms of different kinds, group themselves to molecules. affinity exists between hydrogen and hydrogen and between chlorine and chlorine, as well as between hydrogen and chlorine. we have thus homogeneous molecules as well as heterogeneous molecules, and the neutrality so strikingly exhibited by the elements may be due to a quality of which carbonic acid furnishes a partial illustration. the paired atoms of the elementary molecules may be so out of accord with the periods of the ultra red waves--the vibrating periods of these atoms may, for example, be so rapid--as to disqualify them both from emitting those waves, and from accepting their energy. this would practically destroy their power, both as radiators and absorbers. i have reason to know that a distinguished authority has for some time entertained this hypothesis. we must, however, refresh ourselves by occasional contact with the solid ground of experiment, and an interesting problem now lies before us awaiting experimental solution. suppose two hundred men to be scattered equably throughout the length of pall mall. by timely swerving now and then, a runner from st. james's palace to the athenæum club might be able to get through such a crowd without much hinderance. but supposing the men to close up so as to form a dense file crossing pall mall from north to south; such a barrier might seriously impede, or entirely stop, the runner. instead of a crowd of men, let us imagine a column of molecules under small pressure, thus resembling the sparsely distributed crowd. let us suppose the column to shorten, without change in the quantity of matter, until the molecules are so squeezed together as to resemble the closed file across pall mall. during these changes of density, would the action of the molecules upon a beam of heat passing among them at all resemble the action of the crowd upon the runner? we must answer this question by direct experiment. to form our molecular crowd we place, in the first instance, a gas or vapor in a tube inches long, the ends of which are closed with circular windows, air-tight, but formed of a substance which offers little or no obstruction to the calorific waves. calling the measured value of a heat beam passing through this tube , we carefully determine the proportionate part of this total absorbed by the molecules in the tube. we then gather precisely the same number of molecules into a column . inches long, the one column being thus three and a half times the length of the other. in this case also we determine the quantity of radiant heat absorbed. by the depression of a barometric column, we can easily and exactly measure out the proper quantities of the gaseous body. it is obvious that one mercury inch of vapor, in the long tube, would represent precisely the same amount of matter--or, in other words, the same number of molecules--as ½ inches in the short one; while inches of vapor in the long tube would be equivalent to inches in the short one. the experiments have been made with the vapors of two very volatile liquids, namely, sulphuric ether and hydride of amyl. the sources of radiant heat were, in some cases, an incandescent lime cylinder, and in others a spiral of platinum wire, heated to bright redness by an electric current. one or two of the measurements will suffice for the purposes of illustration. first, then, as regards the lime light; for inch of pressure in the long tube, the absorption was . per cent. of the total beam; while for . inches of pressure in the short tube, the absorption was . per cent., or almost exactly the same as the former. for inches pressure, moreover, in the long tube, the absorption was . per cent.; while for inches in the short tube it was . per cent. of the total beam. thus closely do the absorptions in the two cases run together--thus emphatically do the molecules assert their individuality. as long as their number is unaltered, their action on radiant heat is unchanged. passing from the lime light to the incandescent spiral, the absorptions of the smaller equivalent quantities, in the two tubes, were . and . per cent.; while the absorptions of the larger equivalent quantities were . and . per cent., respectively. this constancy of absorption, when the density of a gas or vapor is varied, i have called "the conservation of molecular action." but it may be urged that the change of density, in these experiments, has not been carried far enough to justify the enunciation of a law of molecular physics. the condensation into less than one-third of the space does not, it may be said, quite represent the close file of men across pall mall. let us therefore push matters to extremes, and continue the condensation till the vapor has been squeezed into a liquid. to the pure change of density we shall then have added the change in the state of aggregation. the experiments here are more easily described than executed; nevertheless, by sufficient training, scrupulous accuracy, and minute attention to details, success may be insured. knowing the respective specific gravities, it is easy, by calculation, to determine the condensation requisite to reduce a column of vapor of definite density and length to a layer of liquid of definite thickness. let the vapor, for example, be that of sulphuric ether, and let it be introduced into our inch tube till a pressure of . inches of mercury is obtained. or let it be hydride of amyl, of the same length, and at a pressure of . inches. supposing the column to shorten, the vapor would become proportionally denser, and would, in each case, end in the production of a layer of liquid exactly one millimeter in thickness.[ ] conversely, a layer of liquid ether or of hydride of amyl, of this thickness, were its molecules freed from the thrall of cohesion, would form a column of vapor inches long, at a pressure of . inches in the one case, and of . inches in the other. in passing through the liquid layer, a beam of heat encounters the same number of molecules as in passing through the vapor layer: and our problem is to decide, by experiment, whether, in both cases, the molecule is not the dominant factor, or whether its power is augmented, diminished, or otherwise overridden by the state of aggregation. [footnote : the millimeter is - th of an inch.] using the sources of heat before mentioned, and employing diathermanous lenses, or silvered minors, to render the rays from those sources parallel, the absorption of radiant heat was determined, first for the liquid layer, and then for its equivalent vaporous layer. as before, a representative experiment or two will suffice for illustration. when the substance was sulphuric ether, and the source of radiant heat an incandescent platinum spiral, the absorption by the column of vapor was found to be . per cent. of the total beam. the absorption of the equivalent liquid layer was next determined, and found to be . per cent. liquid and vapor, therefore, differed from each only . per cent.; in other words, they were practically identical in their action. the radiation from the lime light has a greater power of penetration through transparent substances than that from the spiral. in the emission from both of these sources we have a mixture of obscure and luminous rays; but the ratio of the latter to the former, in the lime light is greater than in the spiral; and, as the very meaning of transparency is perviousness to the luminous rays, the emission in which these rays are predominant must pass most freely through transparent substances. increased transmission implies diminished absorption; and accordingly, the respective absorption of ether vapor and liquid ether, when the lime light was used, instead of being . and . per cent., were found to be vapor.................... . per cent. liquid................... . " no difference whatever being observed between the two states of aggregation. the same was found true of hydride of amyl. this constancy and continuity of the action exerted on the waves of heat when the state of aggregation is changed, i have called "the thermal continuity of liquids and vapors." it is, i think, the strongest illustration hitherto adduced of the conservation of molecular action. thus, by new methods of search, we reach a result which was long ago enunciated on other grounds. water is well known to be one of the most opaque of liquids to the waves of obscure heat. but if the relation of liquids to their vapors be that here shadowed forth, if in both cases the molecule asserts itself to be the dominant factor, then the dispersion of the water of our seas and rivers, as invisible aqueous vapor in our atmosphere, does not annul the action of the molecules on solar and terrestrial heat. both are profoundly modified by this constituent; but as aqueous vapor is transparent, which, as before explained, means pervious to the luminous rays, and as the emission from the sun abounds in such rays, while from the earth's emission they are wholly absent, the vapor screen offers a far greater hinderance to the outflow of heat from the earth toward space than to the inflow from the sun toward the earth. the elevation of our planet's temperature is therefore a direct consequence of the existence of aqueous vapor in our air. flimsy as that garment may appear, were it removed terrestrial life would probably perish through the consequent refrigeration. i have thus endeavored to give some account of a recent incursion into that ultra-sensible world mentioned at the outset of this paper. invited by my publishers, with whom i have now worked in harmony for a period of twenty years, to send some contribution to the first number of their new magazine, i could not refuse them this proof of my good will. j. tyndall alp lusgen, september , * * * * * the german empire has now about , , acres of forest, valued at $ , , , and appropriates $ , even year to increase and maintain the growth of trees. * * * * * apparatus for measuring electricity at the upper school of telegraphy. _electro tuning forks and their uses._--on a former occasion i described an instrument to which, in , i gave the name _electro-tuning fork_, and which is nothing else than a tuning fork whose motion is kept up electrically in such a way as to last indefinitely, provided that the elements of the pile are renewed gradually, and that from time to time the metallic contact is changed, which causes, at every oscillation, the current to pass from the pile into the magnet, which keeps up the vibration. we reproduce herewith, in fig. , a cut showing in projection one of the simplest forms of the apparatus. [illustration: fig. .--constant vibrator.] if we imagine the platinum or steel style, s, of the figure to be done away with, as well as the platinized plate, i, and its communication with the negative pole of the pile, p, we shall have the ordinary instrument kept in operation electrically by the aid of the electro-magnet, e, the style, s, the interrupting plate, i, and the pile. if we preserve the parts above mentioned, the instrument will possess the property of having vibrations of a constant amplitude if sufficient energy be kept up in the pile. in fact, when the amplitude is sufficiently great to cause the style, s, to touch the plate, i, it will be seen that at such a moment the current no longer passes through the electromagnet, and the vibration is no longer maintained. the amplitude cannot exceed an extent which shall permit the style, s, to touch i. under such conditions, the duration of the vibrations remains exactly constant, as does also the vibratory intensity of the entire instrument. the measurement of time, then, by an instrument of this kind is, indeed, as perfect as it could well be. this complication in the arrangement of the apparatus has no importance as regards those tuning forks the number of whose vibrations exceeds a hundred per second, for in such a case these are given an amplitude of a few millimeters only; but it would be of importance with regard to instruments whose number of vibrations is very small, and to which it might be desirable to give great amplitude; for then, as i have long ago shown, the duration of the oscillation would depend a little on the amplitude, but a very little, it is true. i shall not refer now to the applications of these instruments in chronography, but will rather point out first the applications in which they are destined to produce an effective power. for this purpose it is necessary to make them pretty massive. the number of the vibrations depends upon such massiveness, and it is necessity to know the relation which exists between these two quantities in order to be able to construct an instrument under determinate conditions. i made in former years such a research with regard to tuning forks of prismatic form, that is to say, of a constant rectangular section continuing even into the bent portion where the parallel branches are united by a semicylinder, at the middle of which is the wrought iron rod as well as the branches. the _thickness_ of the instrument is the dimension parallel to the vibrations; its _width_ is the dimension which is perpendicular to them, and its _length_ is reckoned from the extremity of the branches up to the middle of the curved portion. it is found that the number of vibrations is independent of the width, proportional to the thickness, and very nearly inverse ratio of the square of the length, provided the latter exceeds ten centimeters. if we represent the length by l, the thickness by e, and the number of vibrations by n, we shall have the following formula: n = k x ( e / l² ) in which k is a constant quantity whose value depends upon the nature of the metal of which the tuning fork is made. this constant varies very little from steel to malleable cast iron, and it may be taken as equal to . thus, then, we have a means of constructing a tuning fork in which two of the three quantities, n, e, l, are given in advance. experience proves that no errors are committed exceeding one or two per cent. it is seen from this that there is a means of increasing the mass of the instrument without changing anything in the thickness, the length or, consequently, the number of vibrations, and this is by increasing the _breadth_. it is in this way that i have succeeded in having long massive tuning forks made of malleable iron, giving no more than to vibrations per second, and vibrating with perfect regularity. fig. , annexed, shows one of these instruments of about centimeters length, whose breadth, e, is from to centimeters, and which makes about fifteen double vibrations per second only. [illustration: fig. .--the electrical tuning fork.] this number might be still further reduced, but at the expense of our being led to exaggerate the longitudinal dimensions of the apparatus in such a way as to make it inconvenient. the object may be attained more simply by loading the branches with slides supporting leaden weights, m, of grammes each. by fixing these slides at different points on the branches, the number of vibrations can be made to vary from simple to double, and even triple. thus, by fixing them at the extremity of the branches the number of the vibrations is reduced to or . there will be seen in the figure the electro-magnet which keeps up the vibration. this is formed of three simple electro-magnets, whose bobbins have a resistance of no more than ohms, and which are united in series. the interrupting plate, p, against which the style, s, rests at each vibration, is capable of a forward movement, or one of recoil, by the aid of a screw, v, and of an eccentric movement which is produced by a small handle, m, and during which its plane remains invariable. this arrangement permits the point of contact of the style and plate to be varied without changing the precision with which the contact takes place, and all the points of the plate to be slowly used in succession before replacing it. the motion is produced by means of a relatively weak pile, whose poles are connected to the terminals, a and a'. three callaud elements of triple surface, renewed one after the other every month at the most, are sufficient to keep up the vibrations continuously, day and night, without interruption, and that too even when the instrument is employed in producing a small mechanical power, as we shall see further on. we have now seen how electro-tuning forks may be constructed of large dimensions, of large mass, and giving a small number of vibrations per second. such instruments are well fitted to perform the role of electrical interrupters, and it was in such a character that one of them figured in the exhibition of the upper school of telegraphy as a type of an interrupter for testing piles. when it is desired to test a pile to ascertain the practicability of employing it in telegraphy, it is necessary to make it perform a work which shall be as nearly as possible identical with that which it will be called on to do, until it is used up, to estimate the duration of such work, to measure regularly the constants of the pile, the electro-motive power, and the internal resistance. usually, in telegraphy, this work consists in sending over a line of a certain resistance intermittent currents, through the intermedium of suitable manipulators. it suffices then to cause the branches of the electro tuning fork to play the role of one of these manipulators. for doing this the tuning fork carries two insulating ebonite or ivory strips, b b (fig. ), which, at every oscillation, abut against vertical brass springs, r. each of these latter is located in front of the platinized point of a screw, v, which is affixed to a small metallic tongue. the springs and tongues are insulated from each other, and are mounted on a piece which may be moved by a screw, v, so as to cause the springs of the strips, b b', to approach or recede according to the amplitude of the instrument's vibrations. each spring and tongue is connected with terminals affixed to the base of the apparatus. one of the poles of one element, p, of the pile is connected with the tongue and corresponding screw, while the other pole is connected with the screw in front of it through the intermedium of a galvanometer, g², which gives the intensity of the intermittent current, and of a resistance coil, b², which performs the role of an artificial telegraph line. the apparatus being set in operation, it will be seen that the current from the pile is emitted once at every vibration. thus there may be exhausted as many pile elements as there are springs, and that, too, simultaneously; and the contacts of the screws and springs can be regulated in such a way that the duration of the emissions shall be the same for all. at the laboratory of the school of telegraphy one of these instruments has operated without interruption, day and night, during eighteen months. [illustration: fig. .--very rapid electric tuning fork] the apparatus shown in fig. is also an interrupting electro-tuning fork, but it makes a much greater number of vibrations than the preceding, and may serve for other electric tests. the operation of the tuning fork is kept up electrically by the aid of the screw, v, and the corresponding plate; of the style, s, and of the fine wire spiral spring, f, both insulated from the fork, from the electro-magnet, n, and from the two wires, f f', which communicate with a pile. the interrupting system is symmetrical with the first. it consists of the style, s, of the spiral spring, f, of the screw, v, and of the plate that this carries at its extremity. the terminal, b, which carries the spring, f, and the rod which carries the screw being insulated from each other, it is only necessary to cause to terminate therein the extremities of a circuit comprising one pile, in order to produce in the circuit a number of interruptions equal to that of the tuning fork's vibrations. provided the lengths of the springs, f and _f'_, are proper, such vibrations will not be altered. moreover, the instrument is so arranged as to produce vibrations whose _duration can be varied at pleasure and kept constant_ during the whole time the experiments last. this is done by modifying the _amplitude_ of the vibrations; for the greater the amplitude, the longer likewise the duration of the contact of the style, s, on the corresponding plate, and the shorter the duration of the interruption. in order to modify the amplitude, the action of the electro-magnet on the branches of the apparatus is made to vary. to effect this, the electro-magnet is made movable perpendicularly by the aid of a screw, v, between two slides, so that the core, n, may be moved with respect to the median line of the branches, and even be raised above them. its action diminishes, necessarily, while it is being raised, and the amplitude of the vibrations likewise diminishes gradually and continuously. it may thus be made, without difficulty, to vary from two to three tenths of a millimeter to three or four millimeters or more. but it is not sufficient to cause the amplitude to vary; it is necessary to measure it and to keep it constant at the value desired. [illustration: fig. ] the measurement is effected by the aid of a very simple apparatus that i have before described under the name of the _vibrating micrometer_. this is a small square of paper carrving a design like that shown in fig. , and which is seen in fig. glued to one of the masses, m, which serve to vary the number of the instrument's vibrations. this figure is in fact, an angle, one of whose sides is graduated into millimeters, for example, and the other forms the edge of a wide black band. the apex of the angle is above and the divided side is perpendicular to the direction of the vibrations. under such conditions, when the fork is vibrating, the apex of the angle, by virtue of the persistence of impressions upon the retina, _seems_ to advance along the graduation in measure as the amplitude of the vibrations increases. if an angle has been drawn such that the slope of one of its sides to the other is one-tenth, it is easy to see that for each millimeter passed over _apparently_ by the apex of the angle, the amplitude will increase by two-tenths of a millimeter. this is the way, then, that the amplitude is measured. on another hand, it suffices to keep the apex of the angle of the micrometer immovable, in order to be sure of the constancy of the tuning fork's amplitude; and this is done, when necessary, by causing the screw, v, to move slightly. the instrument represented in fig. is, moreover, fixed to a support devised by mr. a. duboscq, so as to make it possible to give the tuning fork every position possible with respect to a vertical plane; to raise it or lower it, and to move it backward or forward so that it may be employed for chimography, and in all those experiments in which electro-tuning folks are used. e. mercadier. * * * * * longman's magazine. our origin as a species. by richard owen, c.b., f.r.s. there seems to be a manifest desire in some quarters to anticipate the looked for and, by some, hoped-for proofs of our descent, or rather ascent, from the ape. in the september issue of the _fortnightly review_ a writer cites, in this relation, the "neanderthal skull, which possesses large bosses on the forehead, strikingly suggestive of those which give the gorilla its peculiarly fierce appearance;" and he proceeds: "no other human skull presents so utterly bestial a type as the neanderthal fragment. if one cuts a female gorilla-skull in the same fashion, the resemblance is truly astonishing, and we may say that the only human feature in the skull is its size."[ ] [footnote : grant allen, "on primitive man," p. .] in testing the question as between linnæus and cuvier of the zoological value of the differences between lowest man and highest ape, a naturalist would not limit his comparison of a portion of the human skull with the corresponding one of a female ape, but would extend it to the young or immature gorilla, and also to the adult male; he would then find the generic and specific characters summed up, so far, at least, as a portion or "fragment" of the skull might show them. what is posed as the "neanderthal skull" is the roof of the brain-case, or "calvarium" of the anatomist, including the pent-house overhanging the eye-holes or "orbits." there is no other part of the fragment which can be supposed to be meant by the "large bosses" of the above quotation. and, on this assumption, i have to state that the super-orbital ridge in the calvarium in question is but little more prominent than in certain human skulls of both higher and lower races, and of both the existing and cave-dwelling periods. it is a variable cranial character, by no means indicative of race, but rather of sex. limiting the comparison to that on which the writer quoted bases his conclusions--apparently the superficial extent of the roof plate--its greater extent as compared with that of a gorilla equaling, probably, in weight the entire frame of the individual from the neanderthal cave, is strongly significant of the superiority of size of brain in the cave-dweller. the inner surface moreover indicates the more complex character of the soft organ on which it was moulded; the precious "gray substance" being multiplied by certain convolutions which are absent in the apes. but there is another surface which the unbiased zoologist finds it requisite to compare. in the human "calvarium" in question, the mid-line traced backward from the super-orbital ridge runs along a smooth track. in the gorilla a ridge is raised from along the major part of that tract to increase the surface giving attachment to the biting muscles. such ridge in this position varies only in height in the female and the male adult ape, as the specimens in the british museum demonstrate. in the neanderthal individual, as in the rest of mankind, the corresponding muscles do not extend their origins to the upper surface of the cranium, but stop short at the sides forming the inner wall or boundary of what are called the "temples," defined by johnson as the "upper part of the sides of the head," whence our "biting muscles" are called "temporal," as the side-bones of the skull to which they are attached are also the "temporal bones." in the superficial comparison to which mr. grant allen has restricted himself in bearing testimony on a question which perhaps affects our fellow-creatures, in the right sense of the term, more warmly than any other in human and comparative anatomy, the obvious difference just pointed out ought not to have been passed over. it was the more incumbent on one pronouncing on the paramount problem, because the "sagittal ridge in the gorilla," as in the orang, relates to and signifies the dental character which differentiates all _quadrumana_ from all _bimana_ that have ever come under the ken of the biologist. and this ridge much more "strikingly suggests" the fierceness of the powerful brute-ape than the part referred to as "large bosses." frontal prominences, more truly so termed, are even better developed in peaceful, timid, graminivorous quadrupeds than in the skulls of man or of ape. but before noticing the evidence which the teeth bear on the physical relations of man to brute, i would premise that the comparison must not be limited to a part or "fragment" of the bony frame, but to its totality, as relating to the modes and faculties of locomotion. beginning with the skull--and, indeed, for present aim, limiting myself thereto--i have found that a vertical longitudinal section brings to light in greatest number and of truest value the differential characters between lowest _homo_ and highest _simia_. those truly and indifferently interested in the question may not think it unworthy their time--if it has not already been so bestowed--to give attention to the detailed discussions and illustrations of the characters in question in the second and third volumes of the "transactions of the zoological society."[ ] the concluding memoir, relating more especially to points of approximation in cranial and denial structure of the highest _quadrumane_ to the lowest _bimane_, has been separately published. [footnote : "oseteological contributions to the natural history of the orangs (_pithecus_) and chimpanzees (_troglodites niger_ and _trog. gorilla_)."] i selected from the large and instructive series of human skulls of various races in the museum of the royal college of surgeons that which was the lowest, and might be called most bestial, in its cranial and dental characters. it was from an adult of that human family of which the life-characters are chiefly but truly and suggestively defined in the narrative of cook's first voyage in the endeavor.[ ] [footnote : hawkesworth's th ed., vol. iii., , pp. , , . the skull in question is no , of the "catalogue of the osteology" in the above museum, to, vol. ii, p. , .] not to trespass further on the patience of my readers, i may refer to the "memoir on the gorilla," to, . plate xii. gives a view, natural size, of the vertical and longitudinal section of an australian skull; plate xi. gives a similar view of the skull of the gorilla. reduced copies of these views may be found at p. , figs. , , vol. ii, of my "anatomy of vertebrates." as far as my experience has reached, there is no skull displaying the characters of a quadrumanous species, as that series descends from the gorilla and chimpanzee to the baboon, which exhibits differences, osteal or dental, on which specific and generic distinctions are founded, so great, so marked, as are to be seen, and have been above illustrated, in the comparison of the highest ape with the lowest man. the modification of man's upper limbs for the endless variety, nicety, and perfection of their application, in fulfillment of the behests of his correspondingly developed brain--actions summed up in the term "manipulation"--testify as strongly to the same conclusion. the corresponding degree of modification of the human lower limbs, to which he owes his upright attitude, relieving the manual instruments from all share in station and terrestrial locomotion--combine and concur in raising the group so characterized above and beyond the apes, to, at least, ordinal distinction. the dental characters of mankind bear like testimony. the lowest (melanian), like the highest (caucasian), variety of the bimanal order differs from the quadrumanal one in the order of appearance, and succession to the first set of teeth, of the second or "permanent" set. the foremost incisor and foremost molar are the earliest to appear in that scries; the intermediate teeth are acquired sooner than those behind the foremost molar.[ ] [footnote : "odontography," to, - , p. , plates , , .] in the gorilla and chimpanzee, the rate or course of progress is reversed; the second true molar, or the one behind the first, makes its appearance before the bicuspid molars rise in front of the first; and the third or last of the molars behind the first comes into place before the canine tooth has risen. this tooth, indeed, which occupies part of the interval between the foremost incisor and foremost molar, is the last of the permanent set of teeth to be fully developed in the _quadrumana_; especially in those which, in their order, rank next to the _bimana_. to this differential character add the breaks in the dental series necessitated for the reception of the crowns of the huge canines when the gorilla or chimpanzee shuts its mouth. but the superior value of developmental over adult anatomical characters in such questions as the present is too well known in the actual phase of biology to need comment. in the article on "primeval man," the author states that the cave-men "probably had lower foreheads, with high bosses like the neanderthal skull, and big canine teeth like the naulette jaw."[ ] [footnote : _fortnightly review_, september, p. .] the human lower jaw so defined, from a belgian cave, which i have carefully examined, gives no evidence of a canine tooth of a size indicative of one in the upper jaw necessitating such vacancy in the lower series of teeth which the apes present. there is no such vacancy nor any evidence of a "big canine tooth" in that cave specimen. and, with respect to cave specimens in general, the zoological characters of the race of men they represent must be founded on the rule, not on an exception, to their cranial features. those which i obtained from the cavern at bruniquel, and which are now exhibited in the museum of natural history, were disinterred under circumstances more satisfactorily determining their contemporaneity with the extinct quadrupeds those cave-men killed and devoured than in any other spelæan retreat which i have explored. they show neither "lower foreheads" nor "higher bosses" than do the skulls of existing races of mankind. present evidence concurs in concluding that the modes of life and grades of thought of the men who have left evidences of their existence at the earliest periods hitherto discovered and determined, were such as are now observable in "savages," or the human races which are commonly so called. the industry and pains now devoted to the determination of the physical characters of such races, to their ways of living, their tools and weapons, and to the relations of their dermal, osteal, and dental modifications to those of the mammals which follow next after _bimana_ in the descensive series of mammalian orders, are exemplary. the present phase of the quest may be far from the bourn to yield hereafter trustworthy evidence of the origin of man; but, meanwhile, exaggerations and misstatements of acquired grounds ought especially to be avoided. * * * * * the aba or odika. by w.h. bacheler, m.d. among the many luxuriant and magnificent forest trees of equatorial west africa, none can surpass, for general beauty and symmetry, that which is called by the natives the "aba." when growing alone and undisturbed, its conical outline and dark green foliage remind one very much of the white maples of the northern united states, by a distant view, but, on a nearer approach, a dissimilarity is observed. wherever, in ravines or near the banks of rivers, the soil is moist the most part of the year, there the aba chooses to grow, and during the months of june and july the falling fruits permeate the atmosphere with a delicious fragrance not similar to any other. this, in form, size, and general appearance, is very much like mango apples, so that the natives call mangoes the "white man's aba;" but the wild aba is not much eaten as a fruit, one or two being sufficient for the whole season. the kernel, or seed, is the important and useful part. when the fallen fruit covers the ground, much as apples do in america, the natives go in canoes to gather it, and the number harvested will be in proportion to the industry of the women. the aba plum is about the size of a goose's egg, of a flattened, ovoid shape, and, when ripe, a beautiful golden color. it consists of three distinct parts: the rind, the pulp, and the seed. the pulp consists of a mass extensively interwoven with strong filaments, which apparently grow out of the seed and are with great difficulty separated from it. the seed, reniform in shape, is bivalved, and constitutes about two-thirds of the bulk of the entire plum, and the inner kernel two-thirds the bulk of the seed. in consequence of it being such a high tree and growing in such inconvenient places, i have been unable to procure a specimen of the flowers. as soon as the fruit is brought to the village, all the inhabitants assemble with cutlasses and engage in the work of opening the plums and removing the kernels. the former are thrown away as useless. the seeds are evenly spread on the top of a rack of small sticks, under which a fire is built in the morning, and subjected to the smoke and heat of an entire day. toward evening the heat is greatly augmented, and in a couple of hours the process is completed. the kernels are now soft, and the oil oozing from them, and while yet in this condition they are thrown into an immense trough and throughly beaten and mashed with a pestle. baskets, with banana leaves spread in the inside to prevent the escape of the product, are in readiness, and it is put into them and pressed down. the next day these baskets are suspended in the sun, and at night are brought into the houses to congeal. the process is now finished. the cakes are removed by inversion of the baskets and "bushrope" tied around them, by which the pieces are carried. as thus prepared, odika is highly esteemed by the natives as an article of food, being made into a kind of thick gravy and eaten with boiled plantains. while at an interior mission station on the ogowe river, i made some experiments in soap making. with palm oil i succeeded very well, using for an alkali the old-fashioned lye of ashes. but i was disappointed with the odika, though i learned some peculiar characteristics of it as a grease. by boiling the crude odika, i was unable, as i hoped, to separate the oleaginous from the extraneous matter, of which it contains a large proportion, but when the above-mentioned lye was used instead of water, the mass, instead of saponifying, merely separated; the grease, resembling very much in all particulars ordinary beef tallow, rising to the top of the caldron, while the refuse was precipitated. after clarifying this, it answers instead of oil of theobroma very nicely, and i have used it considerably in making ointments and suppositories with pleasing results. gaboon, w. africa, aug., .--_new remedies._ * * * * * california cedars. the incense cedar (_libocedius decurrens_) is one of the valued trees of the california coast and mountains. it is eminently noted for great rapidity of growth, wonderful lightness, stiffness, and extraordinary durability. a thousand uses have sprung up and are multiplying around this interesting cedar as its most inestimable qualities become better known. fortunately it is one of the most extensively distributed trees of the pacific--found from the coast range north, south to san diego, sierra nevada, southern oregon, and most of the interior mountain region from , to , feet, and it even thrives quite well at , feet altitude, but seeming to give out at , feet, though said to extend to , feet, which is questionable. as usual with the sylva, flora, and fauna, this also is found lowest along the coast, where it finds the requisite temperature and other essentials, with combined moisture. the base and lower trunk somewhat resembles the western juniper (_j. occidentalis_). it is to be noted in general that trees of such broad, outwardly sweeping, or expanded bases seldom blow over, and to the perceptive and artistic eye their significant character is one of firmness and stability. one hundred to two hundred feet high, six to nine feet in diameter (rarely larger) the shaft is often clear of limbs to feet, and although the lower limbs, or even dry branches, may encumber the middle portion, pin-knots do not damage the timber. the massive body tapers more rapidly above than redwood, and is less eccentric than juniper, yet its general port resembles most the best specimens of the latter. the light cinnamon bark is thick and of shreddy-fibered texture, but so concretely compacted as to render the surface evenly ridged by very long, big bars of bark. these sweep obliquely down on the long spiral twist of swift water lines. the top is conic, the foliage is in compressed, flattened sprays, upright, thickened, and somewhat succulent; if not a languid type, at least in no sense rigid. it bears some resemblance to the great western arborvitæ (_thuja gigantea_), but the tiny leaf-scales are opposite and quite awl-pointed. the general hue of the foliage is light yellowish green, warmly tinted, golden and bead tipped, with tiny, oblong male catkins, as the fruit ripens in october and november. the cones are pendulous from the tips of twigs, oblong, and seldom over three-quarters of an inch long, little more than one-third as thick, and for the most part a trifle compressed. the wood is a pale cream-tint in color--a delicate salmon shade. this would hardly warrant the name white cedar, sometimes applied to it, as well as the giant arborvitæ. the extreme lightness of the lumber and its sweetness for packing boxes will commend it for express and commercial purposes, for posts and fencing, and especially railway ties, for sleepers, stringers, and ground timbers of all varieties, and for unnumbered uses, a tithe of which cannot be told in a brief notice. formerly these trees were cut away and burned up, to clear the track for redwood, tamarack, and ponderous pith-pines, etc.; now all else is superseded by this incense cedar. thus is seen how hasty and ill-advised notions give place to genuine merit. a fungus (_dædalus_) attacks and honeycombs it; and riddled as it may occasionally be, still, if spike or nail finds substance enough to hold, or sufficient solidity to resist crushing, then, for many purposes, even such lumber is practically as good as the soundest timber; because when the tree dies the fungus dies, and thenceforth will absorb no more moisture than the soundest part, and is alike imperishable, contrary to common experience in similar cases. this is a timber nearly as lasting as solid granite. for ship or boat lumber, the clear stuff from sound wood is so exceedingly light, stiff, and durable, and so plenty and available, that few timbers excel it, unless the yellow cedar or cyprus (_cupressus nutkaensis_) is excepted, which is a little tougher, stronger, perhaps more elastic, and equally durable, if judged apart from thorough tests and careful data, which, it has been remarked, the apathy or ignorance of some governments appear to deem unworthy their sublime attention. there are said to be in california a thousand times more and better kinds of naval timbers on government lands as important to preserve as the live oaks of the south atlantic states. it has been asserted as probable that, after due investigation, california would be found to possess a vast amount of the best naval timber in the world, a hundredfold more lasting than the best now in use, if a few woods are excepted, of which there is understood to be no very adequate supply. the great washington cedar (_sequoia gigantea_) is another important california tree. the great sequoian timber belt lies along the sierras, upon the first exposed mountain side--moraines of recent retiring glaciers--that face the pacific, from calaveras on the north to near the head of deer creek on the south--a distance of miles, or a little above degrees north to a little below degrees; altitude , to , feet, and rarely , feet. the belt is broken by two gaps, each miles wide, caused by manifest topographical and glacial reasons, one gap between calaveras and tuolumne, the other between fresno and king's river; thence the vast forest trends south, across the broad basins of kaweah and tule, a distance of miles, on fresh moraine soil, ground from high mountain flanks by glaciers. the inscriptions are scarcely marred by post glacial agents, and the contiguous water-worn marks are often so slight in the rock-bound streams as to be measured by a few inches. rarely does one of these sound and vigorous cedars fall, and those that do will lie to , years, scarcely less perishable than the granite on which they grew. the great sequoian ditches, dug at a blow by their fall, and the tree tumuli, always turned up beside the deep root-bowls, remain; but, scientists assert, not a vestige of one outside the present forests has yet presented itself, hence the area has not been diminished during the last , or , years, and probably not at all in post glacial times. these colossal sequoias rise , , and even feet aloft; are to , and in some rare cases feet in diameter, looking like vast columnar pillars of the skies. no known trees of the world compare with them and their kin, the redwoods, for the focused proximity of such a marvelous amount of timber within limited areas--as it were, the highest standard of timber-land capacity. the stage coach passes through one; children and a piano crowd inside another; a trunk furnishes a house for cotillon parties to dance "stout on stumps;" a horse and rider travel within the burnt-out hollows of others, and so on. a single tree would furnish a two-rail fence, to miles long. the tree has great value for wood and lumber.--_n.w. lumberman._ * * * * * a catalogue containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. * * * * * all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. * * * * * all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . , stitched in paper, or $ . . bound in stiff covers. * * * * * combined rates--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway, new york, n.y. * * * * * patents. in connection with the scientific american, messrs. munn & co are solicitors of american and foreign patents, have had years experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws. patents, caveats, trade marks, their costs, and how procured, with hints for procuring advances on inventions. address munn & co., broadway, new york. branch office, cor. f and th sts., washington, d.c. mechanical drawing self-taught: comprising instructions in the selection and preparation of drawing instruments, _elementary instruction in practical mechanical drawing_; together with examples in simple geometry and elementary mechanism, including screw threads, gear wheels, mechanical motions, engines and boilers. by joshua rose, m.e., author of "the complete practical machinist," "the pattern maker's assistant," "the slide valve" illustrated by three hundred and thirty engravings. philadelphia: henry carey baird & co., industrial publishers, booksellers and importers, walnut street. london: sampson low, marston, searle & rivington, crown buildings, fleet street. . copyright by joshua rose. . philadelphia. collins, printer preface. the object of this book is to enable the beginner to learn to make simple mechanical drawings without the aid of an instructor, and to create an interest in the subject by giving examples such as the machinist meets with in his every-day workshop practice. the plan of representing in many examples the pencil lines, and numbering the order in which they are marked, the author believes to possess great advantages for the learner, since it is the producing of the pencil lines that really proves the study, the inking in being merely a curtailed repetition of the pencilling. similarly when the drawing of a piece, such, for example, as a fully developed screw thread, is shown fully developed from end to end, even though the pencil lines were all shown, yet the process of construction will be less clear than if the process of development be shown gradually along the drawing. thus beginning at an end of the example the first pencil lines only may be shown, and as the pencilling progresses to the right-hand, the development may progress so that at the other or left-hand end, the finished inked in and shaded thread may be shown, and between these two ends will be found a part showing each stage of development of the thread, all the lines being numbered in the order in which they were marked. this prevents a confusion of lines, and makes it more easy to follow or to copy the drawing. it is the numerous inquiries from working machinists for a book of this kind that have led the author to its production, which he hopes and believes will meet the want thus indicated, giving to the learner a sufficiently practical knowledge of mechanical drawing to enable him to proceed further by copying such drawings as he may be able to obtain, or by the aid of some of the more expensive and elaborate books already published on the subject. he believes that in learning mechanical drawing without the aid of an instructor the chief difficulty is overcome when the learner has become sufficiently familiar with the instruments to be enabled to use them without hesitation or difficulty, and it is to attain this end that the chapter on plotting mechanical motions and the succeeding examples have been introduced; these forming studies that are easily followed by the beginner; while sufficiently interesting to afford to the student pleasure as well as profit. new york, _february, _. contents. chapter i. the drawing board. the t square the triangles curves selecting and testing drawing instruments lead pencils mixing india ink the drawing paper tracing paper the ink testing and selecting india ink draftsmen's measuring rules chapter ii. the preparation and use of the instruments. preparing the lining pen for use the shapes of the lining pen points oil stoning pen points preparing the circle pen for use the shape for circle pen points shaping circle pens for very small circles a form of pen point recently introduced; forming the pen point the method of oil-stoning circle pen points the needle point and pen point how to use the circle pen german instrument to avoid slipping of a needle point how to use the lining pen applying the ink to the bow-pen using a straight line or lining pen with a t square chapter iii. lines and curves. explanation of simple geometrical terms; radius; explanation of conventional dotted lines a line at a right angle to another; a point; parallel lines a line produced; a line bisected; a line bounding a circle; an arc of a circle; segments of a circle; the chord of an arc; a quadrant of a circle a sector of a circle; a line tangent to a circle; a semicircle; centre of a circle; axis of a cylinder; to draw a circle that shall pass through three given points to find the centre from which an arc of a circle has been struck; the degrees of a circle the protractor to find the angle of one line to another to find the angles of three lines one to the other acute angles and obtuse angles triangles; right angle triangle; obtuse angle triangle; equilateral triangle; isosceles triangle scalene triangle; a quadrangle; quadrilateral or tetragon rhomboid; trapezoid; trapezium the construction of polygons the names of regular polygons the angles of regular polygons; the ellipse form of a true ellipse the use of a trammel for drawing an ellipse to draw a parabola mechanically to draw a parabola by lines to draw a heart cam chapter iv. shadow lines and line-shading. section lining or cross-hatching to represent cylindrical pieces one within the other; to represent a number of pieces one within the other to represent pieces put together and having slots or keyways through them. effects of shading or cross-hatching lines in sectional shading or cross-hatching made to denote the material of which the piece is composed--lead, wood, steel, brass, wrought iron, cast iron line-shading the shade line to indicate the shape of piece; representation of a washer a key drawn with a shade line; shade line applied to a nut; a german pen regulated to draw lines of various breadths example of line-shading in perspective drawing, shown in a pipe threading stock and die a cylindrical pin line-shaded; two cylindrical pieces that join each other; a lathe centre; a piece having a curved outline line-shading applied to a ball or sphere; applied to a pin in a socket shown in section a piece of tube, where the thickness of the tube is shown; where the hollow or hole is seen, the piece shown in section; where the body is bell-mouthed and the hollow curve shown by shading example of line-shading to denote the relative distances of various surfaces from the eye line-shading to denote that the piece represented is of wood; shade-lines being regular or irregular chapter v. marking dimensions. examples in marking dimensions chapter vi. the arrangement of different views. the different views of a mechanical drawing; elevation; plan; general view; a figure to represent a solid cylinder to represent the different sides of a cube; the use of a cross to denote a square a triangular piece requires two or three views to represent a ring having hexagon cross section; examples; a rectangular piece in two views the position of the piece when in its place determines the name of the view in the drawing view of a lever best method of projecting one view from another; the two systems of different views of a piece chapter vii. examples in bolts, nuts and polygons. to represent the thread of a small screw a bolt with a hexagon head united states standard sizes for forged or unfinished bolts and nuts the basis of the franklin institute or united states standard for bolts and nuts; hexagonal or hexagon heads of bolts comparison of hexagon and square heads of bolts; chamfers without chamfer; best plan for view of both square and hexagon heads drawing different views of hexagon heads to draw a square-headed bolt; to draw the end view of a hexagon head use of the triangle to divide circles scales giving the length of the sides of polygons to find what a square body which measures one inch on each side measures across the corners; to find what diameter a cylindrical piece of wood must be turned to which is to be squared, and each side of which square must measure an inch to find a radius across corners of a hexagon or a six sided figure, the length of a side being an inch to draw a stud to pencil in a cap nut; pencilling for a link having the hubs on one side only link with hubs on both sides; pencil lines for a double eye or a knuckle joint double eye or knuckle joint with an offset; a connecting rod end a rod end with a round stem a bolt with a square under the head example in which the corner where the round stem meets the square under the head is sharp; a centre punch giving an example in which the flat sides gradually run out upon a circle, the edges forming curves chapter viii. screw threads and spirals. screw threads for small bolts with the angles of the thread drawn in, and the method of doing this a double thread; a round top and bottom thread such as the whitworth thread; a left hand thread; to draw screw threads of a large diameter drawing the curves for screw threads to draw the united states standard thread to draw a square thread form of template for drawing the curves of threads to show the thread depth in a top or end view of a nut; to draw a spiral spring to obtain an accurate division of the lines that divide the pitch chapter ix. examples for practice. a locomotive spring; a stuffing box and gland; working drawings of a coupling rod; dimensions and directions marked; a connecting rod drawn and put together as it would be for the lathe, vise, or erecting shop drawings for the blacksmith a locomotive frame reducing scales making a drawing to scale chapter x. projections. a spiral wound around a cylinder whose end is cut off at an angle a cylindrical body joining another at a right-angle; a tee for example other examples of tees example of a cylinder intersecting a cone a cylindrical body whose top face if viewed from one point would appear as a straight line, or from another a circle chapter xi. drawing gear wheels. names of the curves and lines of gear teeth how to draw spur wheel teeth professor willis' scale of tooth proportions the application of the scale how to find the curve for the tooth face to trace hypocycloides for the flanks of teeth sectional view of a section of a wheel for showing the dimensions through the arms and hub to draw an edge view of a wheel; rules for drawing the teeth of wheels; bevel gear wheels the construction to find the curves to draw the arcs for the teeth to draw the pitch circle of the inner and small end of the pinion teeth one-half of a bevel gear and an edge view projected from the same a pair of bevel wheels shown in section; drawing of a part of an ames lathe feed motion; small bevel gears example in which part of the gear is shown with teeth in, and the remainder illustrated by circles; drawings of part of the feed motion of a niles horizontal tool work boring mill three bevel gears, one of which is line-shaded; the construction of oval gearing; professor rankine's process for rectifying and subdividing circular arcs various examples of laying out gear wheels chapter xii. plotting mechanical motions. to find how much motion an eccentric will give to its rod to find how much a given amount of motion of a long arm will move the short arm of a lever example of the end of a lever acting directly on a shoe; a short arm having a roller acting upon a larger roller a link introduced in the place of the roller to find the amount of motion of the rod; a lever actuating a plunger in a vertical line, to find how much a given amount of motion of the long arm will actuate the plunger two levers upon their axles or shafts, the arms connected by a link and one arm connected to a rod a lever arm and cam in one piece on a shaft, a shoe sliding on the line, and held against the cam face by the rod, to find the position of the face of the shoe against the cam to find the amount of motion imparted in a straight line to a rod, attached to an eccentric strap examples in drawing the cut off cams employed instead of eccentrics on river steamboats in the western and southern states. different views of a pair of cams the object of using a cam instead of an eccentric method of drawing or marking out a full stroke cam illustration of the lines embracing cut off cams of varying limits of cut-off part played by the stroke of the engine in determining the conformation of cut-off cams; manner of finding essential points of drawings of cutoff cams a cam designed to cut off the steam at five-eighths of the piston stroke three-fourths and seven-eighths cams necessary imperfections in the operations of cut-off cams drawing representing the motion which a crank imparts to a connecting rod plotting out the motion of a shaper link quick return plotting out the whitworth quick return motion employed in machines finding the curves for moulding cutters chapter xiii. examples in line-shading and drawing for line-shaded engravings. arrangement of idle pulleys to guide bolts from one pulley to another; representation of a cutting tool for a planing machine drawings for photo-engraving drawing for an engraver in wood; drawings for engravings by the wax process engraving made by the wax process from a print from a wood engraving; engravings of a boiler drilling machine chapter xiv. shading and coloring drawings. coloring the journals of shafts; simple shading; drawing cast-iron, wrought iron, steel and copper points to be observed in coloring and shading; colored drawings to be glued around their edges to the drawing board; to maintain an even shade of color; mixing colors to graduate the depth of tint for a cylindrical surface the size and use of brushes; light in shading; example for shading a medart pulley brush shading to show by the shading that the surfaces are highly polished; representation of an oil cup; representation of an iron planing machine example in shading of blake's patent direct acting steam pump example of shading an independent condenser chapter xv. examples of engine work. drawings of an automatic high speed engine; side and end views of the engine; vertical section of the cylinder through the valve face valve motion; governor pillow box, block crank-pin, wheel and main journal side and edge view of the connecting rod a two hundred horse power horizontal steam boiler for a stationary engine; cross sectional view of the boiler shell side elevation, end view of the boiler, and setting working drawings of a one hundred horse power engine; plan and side view of the bed plate, with the main bearing and guide bars; cross sections of the bed plate; side elevation of the cylinder, with end view of the same steam chest side and horizontal cross section of the cylinder; steam chest and the valves; cam wrist plate and cut-off mechanism; shaft for the cam plate; cross head; side view and section through the centre of the eccentric and strap construction of the connecting rod index +-----------------------------------------------------------------------+ |transcriber's note: in this text $t$ indicates a larger capital letter.| +-----------------------------------------------------------------------+ mechanical drawing self-taught. chapter i. _the drawing board._ a drawing board should be of soft pine and free from knots, so that it will easily receive the pins or tacks used to fasten down the paper. its surface should be flat and level, or a little rounding, so that the paper shall lie close to its surface, which is one of the first requisites in making a good drawing. its edges should be straight and at a right angle one to the other, and the ends of the battens b b in figure should fall a little short of the edge a of the board, so that if the latter shrinks they will not protrude. the size of the board of course depends upon the size of the paper, hence it is best to obtain a board as small as will answer for the size of paper it is intended to use. the student will find it most convenient as well as cheapest to learn on small drawings rather than large ones, since they take less time to make, and cost less for paper; and although they require more skill to make, yet are preferable for the beginner, because he does not require to reach so far over the board, and furthermore, they teach him more quickly and effectively. he who can make a fair drawing having short lines and small curves can make a better one if it has large curves, etc., because it is easier to draw a large than a very small circle or curve. it is unnecessary to enter into a description of the various kinds of drawing boards in use, because if the student purchases one he will be duly informed of the kinds and their special features, while if he intends to make one the sketch in figure will give him all the information he requires, save that, as before noted, the wood must be soft pine, well seasoned and free from knots, while the battens b should be dovetailed in and the face of the board trued after they are glued and driven in. to true the edges square, it is best to make the two longest edges parallel and straight, and then the ends may be squared from those long edges. [illustration: fig. .] the $t$ square. drawing squares or t squares, as they are termed, are made of wood, of hard rubber and of steel. there are several kinds of t squares; in one the blade is solid, as it is shown in figure on page ; in another the back of the square is pivoted, so that the blade can be set to draw lines at an angle as well as across the board, which is often very convenient, although this double back prevents the triangles, when used in some positions, from coming close enough to the left hand side of the board. in an improved form of steel square, with pivoted blade, shown in figure , the back is provided with a half circle divided into the degrees of a circle, so that the blade can be set to any required degree of angle at once. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] the triangles. [illustration: fig. .] two triangles are all that are absolutely necessary for a beginner. the first is that shown in figure , which is called a triangle of degrees, because its edge a is at that angle to edges b and c. that in figure is called a triangle of degrees, its edge a being at degrees to b, and at degrees to c. the edges p and c are at a right angle or an angle of degrees in both figures; hence they are in this respect alike. by means of these triangles alone, a great many straight line drawings may be made with ease without the use of a drawing square; but it is better for the beginner to use the square at first. the manner of using these triangles with the square is shown in figure , in which the triangle, figure , is shown in three positions marked d e f, and that shown in figure is shown in three positions, marked respectively g h and i. it is obvious, however, that by turning i over, end for end, another position is attained. the usefulness in these particular triangles is because in the various positions shown they are capable of use for drawing a very large proportion of the lines that occur in mechanical drawing. the principal requirement in their use is to hold them firmly to the square-blade without moving it, and without permitting them to move upon it. the learner will find that this is best attained by so regulating the height of the square-blade that the line to be drawn does not come down too near the bottom of the triangle or edge of the square-blade, nor too high on the triangle; that is to say, too near its uppermost point. it is the left-hand edge of the triangle that is used, whenever it can be done, to produce the required line. [illustration: fig. .] curves. to draw curves that are not formed of arcs or parts of circles, templates called curves are provided, examples of these forms being given in figure . they are made in wood and in hard rubber, the latter being most durable; their uses are so obvious as to require no explanation. it may be remarked, however, that the use of curves gives excellent practice, because they must be adjusted very accurately to produce good results, and the drawing pen must be held in the same vertical plane, or the curve drawn will not be true in its outline. drawing instruments. it is not intended or necessary to enter into an elaborate discussion of the various kinds of drawing instruments, since the purchaser can obtain a good set of drawing instruments from a reputable dealer by paying a proportionate price, and must _per force_ learn to use such as his means enable him to purchase. it is recommended that the beginner purchase as good a set of instruments as his means will permit, and that if his means are limited he purchase less than a full set of instruments, having the same of good quality. all the instruments that need be used in the examples of this book are as follows: a small spring bow-pen for circles, a lining pen or pen for straight lines, a small spring bow-pencil for circles, a large bow-pen with a removable leg to replace by a divider leg or a pencil leg, and having an extension piece to increase its capacity. the spring bow-pen should have a stiff spring, and should be opened out to its full capacity to see that the spring acts well when so opened out, keeping the legs stiff when opened for the larger diameters. the purchaser should see that the joint for opening and closing the legs is an easy but not a loose fit on the screw, and that the legs will not move sideways. to test this latter, which is of great importance in the spring bow-pencil as well as in the pen, it is well to close the legs nearly together and taking one leg in one hand and the other leg in the other hand (between the forefinger and thumb), pushing and pulling them sideways, any motion in that direction being sufficient to condemn the instrument. it is safest and best to have the two legs of the bow-pen and pencil made from one piece of metal, and not of two separate pieces screwed together at the top, as the screw will rarely hold them firmly together. the points should be long and fine, and as round as possible. in very small instruments separate points that are fastened with a screw are objectionable, because, in very small circles, they hide the point and make it difficult to apply the instrument to the exact proper point or spot on the drawing. the joints of the large bow or circle-pen should also be somewhat stiff, and quite free from side motion, and the extension piece should be rigidly secured when held by the screw. it is a good plan in purchasing to put in the extension piece, open the joint and the pen to their fullest, and draw a circle, moving the pen in one direction, and then redraw it, moving it in the other direction, and if one line only appears and that not thickened by the second drawing, the pen is a good one. the lead pencil should be of hard lead, and it is recommended that they be of the h, h, h, h, h, h, in the english grades, which corresponds to the v, v, h, of the dixon grade. the pencil lines should be made as lightly as possible; first, because the presence of the lead on the paper tends to prevent the ink from passing to the paper; and, secondly, because in rubbing out the pencil lines the ink lines are reduced in blackness and the surface of the paper becomes roughened, so that it will soil easier and be harder to clean. in order to produce fine pencil lines without requiring a very frequent sharpening of the pencil it is best to sharpen the pencil as in figures and , so that the edge shall be long in the direction in which it is moved, which is denoted by the arrow in figure . but when very fine work is to be done, as in the case of patent office drawings, a long, round point is preferable, because the eye can see plainer just where the pencil will begin to mark and leave off; hence the pencil lines will not be so liable to overrun. [illustration: fig. .] [illustration: fig. .] in place of the ordinary wood-covered lead pencils there may be obtained at the drawing material stores pencil holders for holding the fine, round sticks of lead, and these are by far the best for a learner. they are easier to sharpen, and will slip in the holder, giving warning when the draftsman is pressing them too hard on the paper, as he is apt to do. the best method of trimming these leads, as also lead pencils after they have been roughly shaped, is with a small fine file, holding the file still and moving the pencil; or a good piece of emery paper or sand paper is good, moving the pencil as before. all lines in pencilling as in inking in should begin at the left hand and be drawn towards the right, or when triangles are used the lines are begun at the bottom and drawn towards the top or away from the operator. the rubber used should not be of a harsh grade, since that will roughen the face of the paper and probably cause the ink to run. the less rubbing out the better the learner will progress, and the more satisfaction he will receive from the results. if it becomes necessary to scratch out it is best done with a penknife well sharpened, and not applied too forcibly to the paper but somewhat lightly, and moved in different and not all in one direction. after the penknife the rubber may sometimes be used to advantage, since it will, if of a smooth grade, leave the paper smoother than the knife. finally, before inking in, the surface that has been scraped should be condensed again by rubbing some clean, hard substance over it which will prevent the ink from spreading. the end of a paper-cutter or the end of a rounded ivory handled drawing instrument is excellent for this purpose. [illustration: fig. .] [illustration: fig. .] it is well to use the rubber for general purposes in such a way as to fit it for special purposes; thus, in cleaning the sheet of paper, the rubber may be applied first, as in figure , as at a, and then as at b, and if it be moved sideways at the same time it will wear to the form shown in figure , which will enable it to be applied along a line that may require to be rubbed out without removing other and neighboring lines. if the rubber is in the form of a square stick one end may be bevelled, as in figure , which is an excellent form, or it may be made to have a point, as in figure . the object is in each case to enable the rubber action to be confined to the desired location on the paper, so as to destroy its smooth surface as little as possible. [illustration: fig. .] [illustration: fig .] for simple cleaning purposes, or to efface the pencil lines when they are drawn very lightly, squares of sponge-rubber answer admirably, these being furnished by the dealers in drawing materials. a piece of bread will answer a similar purpose, but it is less convenient. for glazed surface paper, as bristol-board, the smoothest rubber must be used, the grade termed velvet rubber answering well. the drawing paper. whatever kind of drawing paper be used it should be kept dry, or the ink, however good it may be, will be apt to run and make a thick line that will not have the sharp, clean edges necessary to make lines look well. drawing paper is made in various qualities, kinds, and forms, as follows: the sizes and names of paper made in sheets are: cap, Ã� inches. demy, Ã� " medium, Ã� " royal, Ã� " super royal, Ã� " imperial, Ã� " elephant, Ã� " columbier, Ã� " atlas, Ã� " theorem, Ã� " double elephant, Ã� " antiquarian, Ã� " emperor, Ã� " uncle sam, Ã� " the thickness of the sheets increasing with their size. some sheets of paper are hot pressed, to give a smoother surface, and thus enable cleaner-edged lines to be drawn. [illustration: fig. .] for large drawings paper is made in rolls of various widths, but as rolled paper is troublesome to lay flat upon the drawing board, it is recommended to the learner to obtain the sheets, which may be laid sufficiently flat by means of broad headed pins, such as shown in figure , which are called thumb tacks. these are forced through the paper into the board at each corner, as in figure at _f_. on account of the large diameter of the stems of these thumb tacks, which unduly pierce and damage the board, and on account also of their heads, by reason of their thickness, coming in the way of the square blade, it will be found preferable to use the smallest sizes of ordinary iron tacks, with flat heads, whose stems are much finer and heads much thinner than thumb tacks. the objection to ordinary tacks is that they are more difficult to remove, but they are, as stated, more desirable for use. [illustration: fig. .] [illustration: fig. .] if the paper is nearly the full size of the board, it does not much matter as to its precise location on the board, but otherwise it is best to place it as near the left-hand edge of the board as convenient, as is shown in figure . the lower edge, d, figure , of the paper, however, should not be placed too near the edge, a, of the board, because if the end p of the square back comes down below the edge of the board, it is more difficult to keep the square back true against the end of the board. the paper must lie flat upon and close to the surface of the board, and a sufficient number of tacks must be used to effect this purpose. drawings that are to be intricate, or to contain a great many lines, as a drawing of an engine or of a machine, are best pasted or glued all around the edges of the paper, which should first be dampened; but as the learner will scarcely require to make such drawings until he is somewhat familiar with and well practised in the use of the instruments, this part of the subject need not be treated here. tracing paper. for taking tracings from drawings tracing paper or tracing cloth is used. they require to be stretched tightly and without wrinkles upon the drawing. to effect this object the mucilage should be thick, and the tracing paper should be dampened with a sponge after it is pasted. it must be thoroughly dry before use, or the ink will run. tracing cloth must be fastened by pins or thumb tacks, and not dampened. the drawing should be made on the polished side of the cloth, and any coloring to be done should be on the other side, and done after the tracing is removed from the drawing. the ink. india ink should always be used for mechanical drawing: first, because it lies upon and does not sink into the paper, and is, therefore, easily erased; and, secondly, because it does not corrode or injure the drawing instruments. india ink is prepared in two forms--in the stick and in a liquid form. the stick ink is mixed in what are termed saucers, or cabinet saucers, one being placed above the other, so as to exclude the dust from settling in it, and also to prevent the rapid evaporation to which it is subject. the surface of the saucer should be smooth, as any roughness grinds the ink too coarsely, whereas the finer it is ground or mixed the easier it will flow, the less liability to clog the instruments, and the smoother and more flat it will lie upon the paper. in mixing the ink only a small quantity of water should be used, the stick of ink being pressed _lightly_ upon the saucer and moved quickly, the grinding being continued until the ink is mixed quite thickly. this will grind the ink fine as it is mixed, and more water may be added to thin it. it is best, however, to let the ink be somewhat thick for use, and to keep it covered when not in use; and though water may be added if it gets too thick, yet ink that has once dried should not be mixed up again, as it will not work so well after having once dried. of liquid inks the higgins ink is by far the best, being quite equal to and much more convenient for use than the best stick ink. the difference between a good and an inferior india ink lies chiefly in the extent to which the lamp-black, which is the coloring matter, forms with the water a chemical solution rather than a mechanical mixture. in inferior ink the lamp-black is more or less held in suspension, and by prolonged exposure to the air will separate, so that on being spread the solid particles will aggregate by themselves and the water by itself. this explains why draughtsmen will, after the ink has been exposed to the air for an hour or two, add a drop of mucilage to it; the mucilage thickening the solution, adding weight to the water, and deferring the separation of the lamp-black. a good india ink is jet black, flows easily, lies close to, does not stand upon or sink into the paper, and has an even lustre, the latter being an indication of fineness. the more perfect the incorporation of the lamp-black with the water the easier the ink will flow, the less liable it is to clog the instruments, the more even and sharp the edges of the lines, and the finer the lines that may be drawn. usually india ink can only be tested by actual trial; but since it is desirable to test before purchasing it, it may be mentioned that one method is to mix a little on the finger nail, and if it has a "bronzy" gloss it is a good indication. it should also spread out and dry without any tendency to separate. the best method of testing is to mix a very little, and drop a single drop in a tumbler of clear water. the best ink will diffuse itself over the surface, and if the water is disturbed will diffuse itself through the water, leaving it translucent and black, with a slight tinge of bronze color. a coarser ink will act in a similar manner, but make the water somewhat opaque, with a blue-black, or dull, ashy color. a still coarser ink will, when diffused over the surface of the water, show fine specks, like black dust, on the surface. this is readily apparent, showing that the mixture of the ink is not homogeneous. when it is an object to have the lines of a drawing show as black as possible, as for drawings that are to be photo-engraved, the ink should be mixed so thickly as to have a tendency to lift when a body, such as a lead pencil, is lifted out of it. for patent office drawings some will mix it so thickly that under the above test it appears a little stringy. the thicker the ink can be used the better, because the tendency of the carbon to separate is less; and it is for this reason that the test mentioned with a tumbler of water is so accurate. when ink is to be used on parchment, or glossy tracing-paper, it will flow perfectly if a few drops of ox-gall be mixed with it; but on soft paper, or on bristol board, this will cause the ink to spread. for purposes of measurement, there are special rules or scales of steel and of paper manufactured. the steel rules are finely and accurately divided, and some are of triangular form, so that when laid upon the paper the lines divided will lie close to the paper, and the light will fall directly on the ruled surface. triangular rules or scales are therefore much superior to flat ones. the object of having a paper rule or scale is, that the paper will expand and contract under varying degrees of atmospheric moisture, the same as the drawing paper does. figure represents a triangular scale, having upon it six different divisions of the inch. these are made in different patterns, having either decimal divisions or the vulgar fractions. being made of steel, and nickel-plated, they are proof against the moisture of the fingers, and are not subject to the variation of the wooden scale. [illustration: fig. .] chapter ii. _the preparation and use of the instruments._ the points of drawing instruments require to be very accurately prepared and shaped, to enable them to make clean, clear lines. the object is to have the points as sharp as they can be made without cutting the paper, and the curves as even and regular as possible. [illustration: fig. .] [illustration: fig. .] the lining pen should be formed as in figure , which presents an edge and a front view of the points. the inside faces should be flat across, and slightly curved in their lengths, as shown. if this curve is too great, as shown exaggerated in figure , the body of the ink lies too near the point and is apt to flow too freely, running over the pen-point and making a thick, ragged line. on the other hand, if the inside faces, between which the ink lies, are too parallel and narrow near the points, the ink dries in the pen, and renders a too frequent cleaning necessary. looking at the face of the pen as at a in figure , its point should have an even curve, as shown, the edge being as sharp as it can be made without cutting the drawing paper. upon this quality depends the fineness and cleanness of the lines it will make. this thin edge should extend around the curve as far as the dotted line, so that it will be practicable to slant the pen in either of the directions shown in figure ; and it is obvious that its thickness must be equal around the arc, so that the same thickness of line will be drawn whether the pen be held vertical or slanted in either direction. [illustration: fig. .] [illustration: fig. .] the outside faces of the pen should be slightly curved, so that when held vertically, as in figure (the dotted line representing the centre of the length of the instrument), and against the square blade s, the point will meet the paper a short distance from the lower edge of s as shown. by this means it is not necessary to adjust the square edge exactly coincident with the line, but a little way from it. this is an advantage for two reasons: first, the trouble of setting the square-edge exactly coincident is avoided, and, secondly, the liability of the ink to adhere to the edge of the square-blade and flow on to the paper and make a thick, ragged line, is prevented. the square being set as near to the line as desired, the handle may be held at such an angle that the pen-point will just meet the line when sloped either as in figure or . if, however, the slope be too much in the direction shown in figure , practice is necessary to enable the drawing of straight lines if they be long ones, because any variation in the angle of the instrument to the paper obviously vitiates the straightness of the line. if, on the other hand, the square be too close to the line, and the pen therefore requires to be sloped as in figure , the ink flowing from the pen-point is apt to adhere to the square-edge, and the result will be a ragged, thick line, as shown in figure . [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] each of the legs should be of equal thickness at the pen-point edge, so that when closed together the point will be in the middle of the edge. the width and curve of each individual point should be quite equal, and the easiest method of attaining this end is as follows: take a small slip of arkansas oil-stone, and with the pen-points closed firmly by the screw trim the pen-edges to the required curve as shown at a, figure , making the curve as even as possible. then stone the faces until this curve is brought up to a sharp edge at the point between the two pen-legs forming the point. next take a piece of french emery paper, lay it upon some flat body like the blade of a square, and smooth the curve of the edge enough to take off the fine, sharp edge left by the oil-stone; then apply the outside flat faces of the pen to the emery paper again, bringing the pen-edge up sharp. the emery paper will simply have smoothed and polished the surfaces, still leaving them too sharp, so sharp as to cut the paper, and to take off this sharp edge (which must first be done on the inside faces) open the pen-points as wide as the screw will permit. then wrap one thickness of the emery paper upon a thin blade, as upon a drawing-triangle, and pass the open pen-points over it, and move the instrument endwise, taking care to keep the inside face level with the surface of the emery paper, so that the pen-points shall not cut through. next close the pen-points with the screw until they nearly, but not quite, touch, and sweep the edge of the pen-point along the emery paper under a slight pressure, so moving the handle that at each stroke the whole length around the curved end of the pen will meet the emery surface. during this motion the inside faces of the pen-point must be held as nearly vertical as possible, so as to keep the two halves of the pen-point equal. the pen is now ready for use, and will draw a fine and clean line. it is not usual to employ emery paper for the purpose indicated, but it will be found very desirable, since it leaves a smoother surface and edge than the oil-stone alone. circle-pens are more difficult to put in order than the straight-line pen, especially those for drawing the smallest circles, which cannot be well drawn unless the pen is of the precise right shape and in the best condition. a circle-pen is shown in figure , in which a represents the point-leg and b the pen-leg. the point-leg must be the longest because it requires to enter the drawing paper before the pen meets the surface. the point should be sharp and round, for any edges or angles on it will cause it to widen the hole in the paper when it is rotated. to shape the points to prevent the enlargement of the centre in the paper is one of the most important considerations in the use of this instrument, especially when several circles require to be drawn from the same centre. to accomplish this end the inside of the point-leg should be, as near as possible, parallel to the length of the instrument (which is denoted in figure by the dotted line) when the legs are closed, as in the figure. if the point is at an angle, as shown in figure , it is obvious that rotating it will enlarge the top of the centre in the drawing paper. the point should be sharp and smooth on its circumferential surface, and so much longer than the pen-point that it will have sufficient hold in the paper when the instrument stands vertical and the pen-point meets the surface of it, which amount is about / th of an inch. we may now consider the shape of the pen-point. its inside surfaces should be flat across and to the curve shown in figure , not as shown exaggerated in figure , because in the latter the body of the ink will be too near the pen-point, and but little can be placed in it without causing it sometimes to flow over the edges and down the outside of the pen. a form of pen-point recently introduced is shaped as in figure , the object being to have a thin stream of ink near the marking pen-point and the main body of the ink near at hand, instead of extending up the pen, as would be the case with figure . the advantage thus gained is that the ink lies in a more solid body, and having less area of surface exposed to the air will not dry so quickly in the pen; but this is more than offset by the liability of the ink to flow over the crook at a, and cause the pen to draw a thick ragged line. the pen-point must be slightly inclined toward the needle-point, to the end that they may approach each other close enough for drawing very small circles, but it should also stand as nearly vertical as will permit that end to be attained. as this pen is for drawing small circles only, it does not require much ink, and hence may be somewhat close together, as in figure ; this has the advantage that the point is not hidden from observation. in forming the pen-point the greatest refinement is necessary to enable the drawing of very small true circles, say / th of an inch, or less, in diameter. the requirements are that the pen-point shall meet the surface of the paper when the needle-point has entered it sufficiently to give the necessary support, and that the instrument shall stand vertical, as shown by the dotted line in figure . also, that the pen shall then touch the paper at a point only, this point being the apex of a fine curve; that this curve be equal on each side of the point of contact with the paper; that both halves forming the pen be of equal thickness and width at the pointed curve; and that the point be as sharp as possible without cutting the paper. the best method of attaining these ends is as follows: on each side of the pen make, with an oil-stone, a flat place, as c d, figure (where the pen-point is shown magnified), thus bringing both halves to an edge of exactly equal length, and leaving the point flat at d. these flat places must be parallel to one another and to the joint between the two halves of the pen. as the oil-stone may leave a slightly ragged edge, it is a good plan to take a piece of french emery paper, lay it on a flat surface, and holding the instrument vertically remove the fine edge d until it will not cut. then with the oil-stone shape the curved edge as in figure , taking care that the curve no more than brings the flat place d up to a true curve and leaves the edge sharp, with only the very point touching the paper, which is represented in the cut by the horizontal line. [illustration: figures . . . . . .] the point must have a sharp edge all around the curve, and the two halves must be exactly equal in width, for if one half is wider than the other, as in figure at a, or as in figure at b, it will be impossible to draw a very small circle true. so, likewise, the two halves of the pen must be of exactly equal length, and not one half longer than the other, as in figures or , which would tend to cut the paper, and also render the drawing of true small circles impracticable. when the pen is closed to draw a very small circle the two halves of the pen-leg should have an equal degree of contact with the surface of the paper, and then as the legs are opened out to draw larger circles the contact of the outside half of the pen will have less contact with the paper. the smaller the circle, the more difficult it is to keep the point-leg from slipping out of the centre, and the more difficult it is to draw a clear line and true circle; hence the points should be shaped to the best advantage for drawing these small circles, by oil-stoning the pen, as already described, and then finishing it as follows: after the oil-stoning, open the two valves of the pen-leg wide enough to admit a piece of french emery paper wrapped once around a very thin blade, and move the pen endwise as described for the straight-line pen. this will smooth the inner surfaces and remove any fine wire-edge that the oil-stone may leave. close the two halves of the pen again, and lightly emery-paper the outside faces, which will leave the edge sharp enough to cut the paper. the removal of the sharp edge still left, to the exact degree, requires great care. it may best be done by closing the pen until its two halves very nearly, but not quite, touch, then adjust it to mark a circle of about / inch diameter, and strike a number of circles in different locations upon the surface of a piece of french emery paper. in marking these circles, however, let the instrument stand out of the perpendicular, and do very little while standing vertically. indeed, it is well to strike a number of half-circles, first from right to left and then from left to right, and finally draw a full circle, sloping the pen on one side, gradually raising it vertically, and finally sloping it to the other side. this will insure that the pen has contact at its extreme point, and leave that point fine and keen, but not enough so to cut the paper. to test the pen, draw small circles with the pen rotated first in one direction and then in the other, closing its points so as to mark a fine line, which, if the pen is properly shaped, will be clear and fine, while if improperly formed the circle drawn with the pen rotated in one direction will not coincide with that drawn while rotating it in the other. the same circle may be drawn over several times to make a thorough test. if a drawing instrument will draw a fine line correctly, it will be found to answer for thick lines which are more easily made. in thus preparing the instruments, the operator will find that if he occasionally holds the points in the right position with regard to the light, he will be able to see plainly if the work is proceeding evenly and equally, for if one-half of the pen is thicker at the point or edge than the other, it will show a brighter line. this is especially the case with instruments that have become dull by use, for in that case the edges will be found quite bright, and any inequality of thickness shows plainly. [illustration: fig .] [illustration: fig. .] it follows, from what has been said, that the needle-point and pen-point should stand vertical when in use, and to effect this the instruments, except in the smallest sizes, are provided with joints, such as shown at a and b in the bow-pencil or circle-pencil, in figure . these joints should be sufficiently stiff that they will not move too easily, and yet will move rather than that the legs should sensibly spring without moving at the joint. the needle-point leg should be adjusted by means of the joint, to stand vertical, and the same remarks apply equally to the pen-leg; but in the case of the pencil-leg it is the pencil itself and not the leg that requires attention, the joint b being so adjusted that the pencil either stands vertical, or, what is perhaps preferable, so that it stands inclined slightly towards the needle-point. in sharpening the pencil the inner face c may be made concave or at least vertical and flat, and the outer convex or else bevelled and flat, producing a fine and long edge rounded in its length of edge. in using the circle-pencil and circle-pen it will be found more convenient to rotate it in the direction of the arrow in figure . it should be held lightly to the paper, and the learner will find that he has a natural tendency to hold it too firmly and press it too heavily, which is _especially to be avoided_. if in drawing a small circle the needle-point slips out of the paper, it is because the pencil-point is too long; or, what is the same thing, the needle-point does not protrude far enough out from the leg. or if the instrument requires to be leaned over too much to make the pencil or pen mark, it is because the pen or pencil is not far enough out, and this again may cause the needle-point to slip out of the paper. [illustration: fig. .] [illustration: fig. .] in figure is shown a german instrument especially designed to avoid this slipping. the peculiarity of this instrument consists in the arrangement of the centre point, which remains stationary whilst the pen or pencil, resting by its own weight on the paper, is guided round by gently turning, without pressure, the small knob at the upper end of the tube. by this means the misplacing or sliding of the centre-point and the cutting of the paper by the pen are avoided. by means of this fixed centre-point any number of concentric circles may be drawn, without making a hole of very distinguishable size on the paper. [illustration: fig .] in applying the ink to the bow-pen as to all other instruments, care must be taken that the ink lies between the points only and not on the outside, for in the latter case the ink will flow down too freely and make a broad, ragged line, perhaps getting on the edge of the square blade or triangle, and causing a blot of ink on the drawing. in using a straight line or lining pen with a t square it may be used as in figure , being nearly vertical, as shown, and moved from left to right as denoted by the arrow, s representing the square blade. but in using it, or a pencil, with a straight edge or a triangle unsupported by the square blade, the latter should be steadied by letting the fingers rest upon it while using the instrument, the operation being shown in figure . the position, figure , is suitable for long lines, and that in figure for small drawings, where the pen requires close adjustment to the lines. chapter iii. _lines and curves._ although the beginner will find that a study of geometry is not essential to the production of such elementary examples of mechanical drawing as are given in this book, yet as more difficult examples are essayed he will find such a study to be of great advantage and assistance. meantime the following explanation of simple geometrical terms is all that is necessary to an understanding of the examples given. the shortest distance between two points is termed the radius; and, in the case of a circle, means the distance from the centre to the perimeter measured in a straight line. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] dotted lines, thus, <----->, mean the direction and the points at which a dimension is taken or marked. dotted lines, thus,-----, simply connect the same parts or lines in different views of the object. thus in figure are a side and an end view of a rivet, and the dotted lines show that the circles on the end view correspond to the circle of the diameters of the head and of the stem, and therefore represent their diameters while showing that both are round. a straight line is in geometry termed a right line. a line at a right angle to another is said to be perpendicular to it; thus, in figures , , and , lines a are in each case perpendicular to line b, or line b is in each case perpendicular to line a. a point is a position or location supposed to have no size, and in cases where necessary is indicated by a dot. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] parallel lines are those equidistant one from the other throughout their length, as in figure . lines maybe parallel though not straight; thus, in figure , the lines are parallel. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] a line is said to be _produced_ when it is extended beyond its natural limits: thus, in figure , lines a and b are _produced_ in the point c. a line is bisected when the centre of its length is marked: thus, line a in figure is bisected, at or in, as it is termed, _e_. the line bounding a circle is termed its circumference or periphery and sometimes the perimeter. a part of this circumference is termed an arc of a circle or an arc; thus figure represents an arc. when this arc has breadth it is termed a segment; thus figures and are segments of a circle. a straight line cutting off an arc is termed the chord of the arc; thus, in figure , line a is the chord of the arc. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] a quadrant of a circle is one quarter of the same, being bounded on two of its sides by two radial lines, as in figure . when the area of a circle that is enclosed within two radial lines is either less or more than one quarter of the whole area of the circle the figure is termed a sector; thus, in figure , a and b are both sectors of a circle. a straight line touching the perimeter of a circle is said to be tangent to that circle, and the point at which it touches is that to which it is tangent; thus, in figure , line a is tangent to the circle at point b. the half of a circle is termed a semicircle; thus, in figure , a b and c are each a semicircle. [illustration: fig. .] [illustration: fig. .] the point from which a circle or arc of a circle is drawn is termed its centre. the line representing the centre of a cylinder is termed its axis; thus, in figure , dot _d_ represents the centre of the circle, and line _b b_ the axial line of the cylinder. to draw a circle that shall pass through any three given points: let a b and c in figure be the points through which the circumference of a circle is to pass. draw line d connecting a to c, and line e connecting b to c. bisect d in f and e in g. from f as a centre draw the semicircle o, and from g as a centre draw the semicircle p; these two semicircles meeting the two ends of the respective lines d e. from b as a centre draw arc h, and from c the arc i, bisecting p in j. from a as a centre draw arc k, and from c the arc l, bisecting the semicircle o in m. draw a line passing through m and f, and a line passing through j and q, and where these two lines intersect, as at q, is the centre of a circle r that will pass through all three of the points a b and c. [illustration: fig. .] [illustration: fig. .] to find the centre from which an arc of a circle has been struck: let a a in figure be the arc whose centre is to be found. from the extreme ends of the arc bisect it in b. from end a draw the arc c, and from b the arc d. then from the end a draw arc g, and from b the arc f. draw line h passing through the two points of intersections of arcs c d, and line i passing through the two points of intersection of f g, and where h and i meet, as at j, is the centre from which the arc was drawn. a degree of a circle is the / part of its circumference. the whole circumference is supposed to be divided into equal divisions, which are called the degrees of a circle; but, as one-half of the circle is simply a repetition of the other half, it is not necessary for mechanical purposes to deal with more than one-half, as is done in figure . as the whole circle contains degrees, half of it will contain one-half of that number, or ; a quarter will contain , and an eighth will contain degrees. in the protractors (as the instruments having the degrees of a circle marked on them are termed) made for sale the edges of the half-circle are marked off into degrees and half-degrees; but it is sufficient for the purpose of this explanation to divide off one quarter by lines degrees apart, and the other by lines degrees apart. the diameter of the circle obviously makes no difference in the number of decrees contained in any portion of it. thus, in the quarter from to , there are degrees, as marked; but suppose the diameter of the circle were that of inner circle _d_, and one-quarter of it would still contain degrees. [illustration: fig. .] so, likewise, the degrees of one line to another are not always taken from one point, as from the point o, but from any one line to another. thus the line marked is degrees from line , or line is degrees from line . similarly in the other quarter of the circle degrees are marked. this may be explained further by stating that the point o or zero may be situated at the point from which the degrees of angle are to be taken. here it may be remarked that, to save writing the word "degrees," it is usual to place on the right and above the figures a small °, as is done in figure , the ° meaning sixty degrees, the °, of course, standing for degrees. [illustration: fig. .] suppose, then, we are given two lines, as _a_ and _b_ in figure , and are required to find their angle one to the other. then, if we have a protractor, we may apply it to the lines and see how many degrees of angle they contain. this word "contain" means how many degrees of angle there are between the lines, which, in the absence of a protractor, we may find by prolonging the lines until they meet in a point as at _c_. from this point as a centre we draw a circle d, passing through both lines _a_, _b_. all we now have to do is to find what part, or how much of the circumference, of the circle is enclosed within the two lines. in the example we find it is the one-twelfth part; hence the lines are degrees apart, for, as the whole circle contains , then one-twelfth must contain , because ÷ = . [illustration: fig. .] if we have three lines, as lines a b and c in figure , we may find their angles one to the other by projecting or prolonging the lines until they meet as at points d, e, and f, and use these points as the centres wherefrom to mark circles as g, h, and i. then, from circle h, we may, by dividing it, obtain the angle of a to b or of b to a. by dividing circle i we may obtain the angle of a to c or of c to a, and by dividing circle g we may obtain the angle of b to c or of c to b. [illustration: fig. .] it may happen, and, indeed, generally will do so, that the first attempt will not succeed, because the distance between the lines measured, or the arc of the circle, will not divide the circle without having the last division either too long or too short, in which case the circle may be divided as follows: the compasses set to its radius, or half its diameter, will divide the circle into equal divisions, and each of these divisions will contain degrees of angle, because (the number of degrees in the whole circle) ÷ (the number of divisions) = , the number of degrees in each division. we may, therefore, subdivide as many of the divisions as are necessary for the two lines whose degrees of angle are to be found. thus, in figure , are two lines, c, d, and it is required to find their angle one to the other. the circle is divided into six divisions, marked respectively from to , the division being made from the intersection of line c with the circle. as both lines fall within less than a division, we subdivide that division as by arcs _a_, _b_, which divide it into three equal divisions, of which the lines occupy one division. hence, it is clear that they are at an angle of degrees, because twenty is one-third of sixty. when the number of degrees of angle between two lines is less than , the lines are said to form an acute angle one to the other, but when they are at more than degrees of angle they are said to form an obtuse angle. thus, in figure , a and c are at an acute angle, while b and c are at an obtuse angle. f and g form an acute angle one to the other, as also do g and b, while h and a are at an obtuse angle. between i and j there are degrees of angle; hence they form neither an acute nor an obtuse angle, but what is termed a right-angle, or an angle of degrees. e and b are at an obtuse angle. thus it will be perceived that it is the amount of inclination of one line to another that determines its angle, irrespective of the positions of the lines, with respect to the circle. [illustration: fig. .] triangles. a right-angled triangle is one in which two of the sides are at a right angle one to the other. figure represents a right-angled triangle, a and b forming a right angle. the side opposite, as c, is called the hypothenuse. the other sides, a and b, are called respectively the base and the perpendicular. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] an acute-angled triangle has all its angles acute, as in figure . an obtuse-angled triangle has one obtuse angle, as a, figure . when all the sides of a triangle are equal in length and the angles are all equal, as in figure , it is termed an equilateral triangle, and either of its sides may be called the base. when two only of the sides and two only of the angles are equal, as in figure , it is termed an isosceles triangle, and the side that is unequal, as a in the figure, is termed the base. [illustration: fig. .] [illustration: fig. .] when all the sides and angles are unequal, as in figure , it is termed a scalene triangle, and either of its sides may be called the base. the angle opposite the base of a triangle is called the vertex. [illustration: fig. .] [illustration: fig. .] a figure that is bounded by four straight lines is termed a quadrangle, quadrilateral or tetragon. when opposite sides of the figure are parallel to each other it is termed a parallelogram, no matter what the angle of the adjoining lines in the figure may be. when all the angles are right angles, as in figure , the figure is called a rectangle. if the sides of a rectangle are of equal length, as in figure , the figure is called a square. if two of the parallel sides of a rectangle are longer than the other two sides, as in figure , it is called an oblong. if the length of the sides of a parallelogram are all equal and the angles are not right angles, as in figure , it is called a rhomb, rhombus or diamond. if two of the parallel sides of a parallelogram are longer than the other two, and the angles are not right angles, as in figure , it is called a rhomboid. if two of the parallel sides of a quadrilateral are of unequal lengths and the angles of the other two sides are not equal, as in figure , it is termed a trapezoid. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] if none of the sides of a quadrangle are parallel, as in figure , it is termed a trapezium. the construction of polygons. [illustration: fig. _a_.] [illustration: fig. .] the term polygon is applied to figures having flat sides equidistant from a common centre. from this centre a circle may be struck that will touch all the corners of the sides of the polygon, or the point of each side that is central in the length of the side. in drawing a polygon, one of these circles is used upon which to divide the figure into the requisite number of divisions for the sides. when the dimension of the polygon across its corners is given, the circle drawn to that dimension circumscribes the polygon, because the circle is without or outside of the polygon and touches it at its corners only. when the dimension across the flats of the polygon is given, or when the dimension given is that of a circle that can be inscribed or marked within the polygon, touching its sides but not passing through them, then the polygon circumscribes or envelops the circle, and the circle is inscribed or marked within the polygon. thus, in figure _a_, the circle is inscribed within the polygon, while in figure the polygon is circumscribed by the circle; the first is therefore a circumscribed and the second an inscribed polygon. a regular polygon is one the sides of which are all of an equal length. names of regular polygons. a figure of sides is called a trigon. " " " tetragon. polygon " " pentagon. " " " hexagon. " " " heptagon. " " " octagon. " " " enneagon or nonagon. [illustration: fig. .] [illustration: fig. .] the angles of regular polygons are designated by their degrees of angle, "at the centre" and "at the circumference." by the angle at the centre is meant the angle of a side to a radial line; thus in figure is a hexagon, and at c is a radial line; thus the angle of the side d to c is degrees. or if at the two ends of a side, as a, two radial lines be drawn, as b, c, then the angles of these two lines, one to the other, will be the "angle at the centre." the angle at the circumference is the angle of one side to its next neighbor; thus the angle at the circumference in a hexagon is degrees, as shown in the figure for the sides e, f. it is obvious that as all the sides are of equal length, they are all at the same angle both to the centre and to one another. in figure is a trigon, the angles at its centre being , and the angle at the circumference being , as marked. the angles of regular polygons: trigon, at the centre, °, at the circumference, °. tetragon, " °, " " °. pentagon, " °, " " °. hexagon, " °, " " °. octagon, " °, " " °. enneagon, " °, " " °. decagon, " °, " " °. dodecagon, " °, " " °. the ellipse. an ellipse is a figure bounded by a continuous curve, whose nature will be shown presently. the dimensions of an ellipse are taken at its extreme length and narrowest width, and they are designated in three ways, as by the length and breadth, by the major and minor axis (the major axis meaning the length, and the minor the breadth of the figure), and the conjugate and transverse diameters, the transverse meaning the shortest, and the conjugate the longest diameter of the figure. in this book the terms major and minor axis will be used to designate the dimensions. the minor and major axes are at a right angle one to the other, and their point of intersection is termed the axis of the ellipse. in an ellipse there are two points situated upon the line representing the major axis, and which are termed the foci when both are spoken of, and a focus when one only is referred to, foci simply being the plural of focus. these foci are equidistant from the centre of the ellipse, which is formed as follows: two pins are driven in on the major axis to represent the foci a and b, figure , and around these pins a loop of fine twine is passed; a pencil point, c, is then placed in the loop and pulled outwards, to take up the slack of the twine. the pencil is held vertical and moved around, tracing an ellipse as shown. [illustration: fig. .] now it is obvious, from this method of construction, that there will be at every point in the pencil's path a length of twine from the final point to each of the foci, and a length from one foci to the other, and the length of twine in the loop remaining constant, it is demonstrated that if in a true ellipse we take any number of points in its curve, and for each point add together its distance to each focus, and to this add the distance apart of the foci, the total sum obtained will be the same for each point taken. [illustration: fig. .] [illustration: fig. .] in figures and are a series of ellipses marked with pins and a piece of twine, as already described. the corresponding ellipses, as a in both figures, were marked with the same loop, the difference in the two forms being due to the difference in distance apart of the foci. again, the same loop was used for ellipses b in both figures, as also for c and d. from these figures we perceive that-- st. with a given width or distance apart of foci, the larger the dimensions are the nearer the form of the figure will approach to that of a circle. d. the nearer the foci are together in an ellipse, having any given dimensions, the nearer the form of the figure will approach that of a circle. d. that the proportion of length to width in an ellipse is determined by the distance apart of the foci. th. that the area enclosed within an ellipse of a given circumference is greater in proportion as the distance apart of the foci is diminished; and, th. that an ellipse may be given any required proportion of width to length by locating the foci at the requisite distance apart. the form of a true ellipse may be very nearly approached by means of the arcs of circles, if the centres from which those arcs are struck are located in the most desirable positions for the form of ellipse to be drawn. [illustration: fig. .] thus in figure are three ellipses whose forms were pencilled in by means of pins and a loop of twine, as already described, but which were inked in by finding four arcs of circles of a radius that would most closely approach the pencilled line; _a b_ are the foci of all three ellipses a, b, and c; the centre for the end curves of _a_ are at _c_ and _d_, and those for its side arcs are at _e_ and _f_. for b the end centres are at _g_ and _h_, and the side centres at _i_ and _j_. for c the end centres are at _k_, _l_, and the side centres at _m_ and _n_. it will be noted that, first, all the centres for the end curves fall on the line of the length or major axis, while all those for the sides fall on the line of width or the minor axis; and, second, that as the dimensions of the ellipses increase, the centres for the arcs fall nearer to the axis of the ellipse. now in proportion as a greater number of arcs of circles are employed to form the figure, the nearer it will approach the form of a true ellipse; but in practice it is not usual to employ more than eight, while it is obvious that not less than four can be used. when four are used they will always fall somewhere on the lines on the major and minor axis; but if eight are used, two will fall on the line of the major axis, two on the line of the minor axis, and the remaining four elsewhere. [illustration: fig. .] in figure is a construction wherein four arcs are used. draw the line _a b_, the major axis, and at a right angle to it the line _c d_, the minor axis of the figure. now find the difference between the length of half the two axes as shown below the figure, the length of line _f_ (from _g_ to _i_) representing half the length of the figure (as from _a_ to _e_), and the length or radius from _g_ to _h_ equalling that from _e_ to _d_; hence from _h_ to _i_ is the difference between half the major and half the minor axis. with the radius (_h i_), mark from _e_ as a centre the arcs _j k_, and join _j k_ by line _l_. take half the length of line _l_ and from _j_ as a centre mark a line on _a_ to the arc _m_. now the radius of _m_ from _e_ will be the radius of all the centres from which to draw the figure; hence we may draw in the circle _m_ and draw line _s_, cutting the circle. then draw line _o_, passing through _m_, and giving the centre _p_. from _p_ we draw the line _q_, cutting the intersection of the circle with line _a_ and giving the centre _r_. from _r_ we draw line _s_, meeting the circle and the line _c, d_, giving us the centre _t_. from _t_ we draw line _u_, passing through the centre _m_. these four lines _o_, _q_, _s_, _u_ are prolonged past the centres, because they define what part of the curve is to be drawn from each centre: thus from centre _m_ the curve from _v_ to _w_ is drawn, from centre _t_ the curve from _w_ to _x_ is drawn. from centre _r_ the curve from _x_ to _y_ is drawn, and from centre _p_ the curve from _y_ to _v_ is drawn. it is to be noted, however, that after the point _m_ is found, the remaining lines may be drawn very quickly, because the line _o_ from _m_ to _p_ may be drawn with the triangle of degrees resting on the square blade. the triangle may be turned over, set to point _p_ and line _q_ drawn, and by turning the triangle again the line _s_ may be drawn from point _r_; finally the triangle may be again turned over and line _u_ drawn, which renders the drawing of the circle _m_ unnecessary. to draw an elliptical figure whose proportion of width to breadth shall remain the same, whatever the length of the major axis may be: take any square figure and bisect it by the line a in figure . draw, in each half of the square, the diagonals e f, g h. from p as a centre with the radius p r draw the arc s e r. with the same radius draw from o as a centre the arc t d v. with radius l c draw arc r c v, and from k as a centre draw arc s b t. [illustration: fig. .] [illustration: fig. .] a very near approach to the true form of a true ellipse may be drawn by the construction given in figure , in which a a and b b are centre lines passing through the major and minor axis of the ellipse, of which _a_ is the axis or centre, _b c_ is the major axis, and _a e_ half the minor axis. draw the rectangle _b f g c_, and then the diagonal line _b e_; at a right angle to _b e_ draw line _f h_, cutting b b at _i_. with radius _a e_ and from _a_ as a centre draw the dotted arc _e j_, giving the point _j_ on line b b. from centre _k_, which is on the line b b and central between _b_ and _j_, draw the semicircle _b m j_, cutting a a at _l_. draw the radius of the semicircle _b m j_, cutting it at _m_, and cutting _f g_ at _n_. with the radius _m n_ mark on a a at and from _a_ as a centre the point _o_. with radius _h o_ and from centre _h_ draw the arc _p o q_. with radius _a l_ and from _b_ and _c_ as centres, draw arcs cutting _p o q_ at the points _p q_. draw the lines _h p r_ and _h q s_ and also the lines _p i t_ and _q v w_. from _h_ as a centre draw that part of the ellipse lying between _r_ and _s_, with radius _p r_; from _p_ as a centre draw that part of the ellipse lying between _r_ and _t_, with radius _q s_, and from _q_ as a centre draw the ellipse from _s_ to _w_, with radius _i t_; and from _i_ as a centre draw the ellipse from _t_ to _b_ and with radius _v w_, and from _v_ as a centre draw the ellipse from _w_ to _c_, and one-half of the ellipse will be drawn. it will be seen that the whole construction has been performed to find the centres _h_, _p_, _q_, _i_ and _v_, and that while _v_ and _i_ may be used to carry the curve around on the other side of the ellipse, new centres must be provided for _h_ _p_ and _q_, these new centres corresponding in position to _h_ _p_ _q_. divesting the drawing of all the lines except those determining its dimensions and the centres from which the ellipse is struck, we have in figure the same ellipse drawn half as large. the centres _v_, _p_, _q_, _h_ correspond to the same centres in figure , while _v'_, _p'_, _q'_, _h'_ are in corresponding positions to draw in the other half of the ellipse. the length of curve drawn from each centre is denoted by the dotted lines radiating from that centre; thus, from _h_ the part from _r_ to _s_ is drawn; from _h'_ that part from _r'_ to _s'_. at the ends the respective centres _v_ are used for the parts from _w_ to _w'_ and from _t_ to _t'_ respectively. [illustration: fig. .] [illustration: fig. .] the most correct method of drawing an ellipse is by means of an instrument termed a trammel, which is shown in figure . it consists of a cross frame in which are two grooves, represented by the broad black lines, one of which is at a right angle to the other. in these grooves are closely fitted two sliding blocks, carrying pivots e f, which may be fastened to the sliding blocks, while leaving them free to slide in the grooves at any adjusted distance apart. these blocks carry an arm or rod having a tracing point (as pen or pencil) at g. when this arm is swept around by the operator, the blocks slide in the grooves and the pen-point describes an ellipse whose proportion of width to length is determined by the distance apart of the sliding blocks, and whose dimensions are determined by the distance of the pen-point from the sliding block. to set the instrument, draw lines representing the major and minor axes of the required ellipse, and set off on these lines (equidistant from their intersection), to mark the required length and width of ellipse. place the trammel so that the centre of its slots is directly over the point or centre from which the axes are marked (which may be done by setting the centres of the slots true to the lines passing through the axis) and set the pivots as follows: place the pencil-point g so that it coincides with one of the points as c, and place the pivot e so that it comes directly at the point of intersection of the two slots, and fasten it there. then turn the arm so that the pencil-point g coincides with one of the points of the minor axis as d, the arm lying parallel to b d, and place the pivot f over the centre of the trammel and fasten it there, and the setting is complete. [illustration: fig. .] to draw a parabola mechanically: in figure c d is the width and h j the height of the curve. bisect h d in k. draw the diagonal line j k and draw k e, cutting k at a right angle to j k, and produce it in e. with the radius h e, and from j as a centre, mark point f, which will be the focus of the curve. at any convenient distance above j fasten a straight-edge a b, setting it parallel to the base c d of the parabola. place a square s with its back against the straight-edge, setting the edge o n coincident with the line j h. place a pin in the focus f, and tie to it one end of a piece of twine. place a tracing-point at j, pass the twine around the tracing-point, bringing down along the square-blade and fasten it at n, with the tracing-point kept against the edge of the square and the twine kept taut; slide the square along the straight-edge, and the tracing-point will mark the half j c of the parabola. turn the square over and repeat the operation to trace the other half j d. this method corresponds to the method of drawing an ellipse by the twine and pins, as already described. [illustration: fig. .] to draw a parabola by lines: bisect the width a b in figure , and divide each half into any convenient number of equal divisions; and through these points of division draw vertical lines, as , , , etc. (in each half). divide the height a d at one end and b e at the other into as many equal divisions as the half of a b is divided into. from the points of divisions , , , etc., on lines a d and b e, draw lines pointing to c, and where these lines intersect the corresponding vertical lines are points through which the curve may be drawn. thus on the side a d of the curve, the intersection of the two lines marked is a point in the curve; the intersection of the two lines marked is another point in the curve, and so on. to draw a heart cam. [illustration: fig. .] draw the line a b, figure , equal to the length of stroke required. divide it into any number of equal parts, and from c as a centre draw circles through the points of division. draw the outer circle and divide its circumference into twice as many equal divisions as the line a b was divided into. draw radial lines from each point of division on the circle, and the points of intersection of the radial lines with the circles are points for the outline of the cam, and through these points a curved line may be drawn giving the shape of the cam. it is obvious that the greater the number of divisions on a b, the more points and the more perfect the curve may be drawn. chapter iv. _shadow lines and line shading._ section lining or cross-hatching. when the interior of a piece is to be shown as a piece cut in half, or when a piece is broken away, as is done to make more of the parts show, or show more clearly, the surface so broken away or cut off is section-lined or cross-hatched; that is to say, diagonal lines are drawn across it, and to distinguish one piece from another these lines are drawn at varying angles and of varying widths apart. in figure is given a view of three cylindrical pieces. it may be known to be a sectional view by the cross-hatching or section lines. it would be a difficult matter to represent the three pieces put together without showing them in section, because, in an outline view, the collars and recesses would not appear. each piece could of course be drawn separately, but this would not show how they were placed when put together. they could be shown in one view if they were shaded by lines and a piece shown broken out where the collars and, recesses are, but line shading is too tedious for detail drawings, beside involving too much labor in their production. [illustration: fig. .] figure represents a case in which there are three cylindrical pieces one within the other, the two inner ones being fastened together by a screw which is shown dotted in in the end view, and whose position along the pieces is shown in the side view. the edges of the fracture in the outer piece are in this case cross-hatched, to show the line of fracture. [illustration: fig. .] [illustration: fig. .] in cross-hatching it is better that the diagonal lines do not quite meet the edges of the piece, than that they should in the least overrun, as is shown in figure , where in the top half the diagonals slightly overrun, while in the lower half they do not quite meet the outlines of the piece. in figure are shown in section a number of pieces one within the other, the central bore being filled with short plugs. all the cross-hatching was done with the triangle of degrees and that of degrees. it is here shown that with these two triangles only, and a judicious arrangement of the diagonals, an almost infinite number of pieces may be shown in cross section without any liability of mistaking one for the other, or any doubt as to the form and arrangement of the pieces; for, beside the difference in spacing in the cross-hatching, there are no two adjoining pieces with the diagonals running in the same direction. it will be seen that the narrow pieces are most clearly defined by a close spacing of the cross-hatching. [illustration: fig. .] in figure are shown three pieces put together and having slots or keyways through them. the outer shell is shown to be in one piece from end to end, because the cross-hatching is not only equally spaced, but the diagonals are in the same direction; hence it would be known that d, f, h, and e were slots or recesses through the piece. the same remarks apply to piece b, wherein g, j, k are recesses or slots. piece c is shown to have in its bore a recess at l. in the case of b, as of a, there would be no question as to the piece being all one from end to end, notwithstanding that the two ends are completely severed where the slots g, i, come, because the spacing and direction of the cross-hatching are equal on each side of the slots, which they would not be if they were separate pieces. [illustration: fig. .] [illustration: fig. .] section shading or cross-hatching may sometimes cause the lines of the drawing to appear crooked to the eye. thus, in figure , the key edge on the right appears curved inwards, while on the left the key edge appears curved outwards, although such is not actually the case. the same effect is produced in figure on the right-hand edge of the key, but not on the left-hand edge. [illustration: fig. ] [illustration: fig. .] a remarkable instance of this kind is shown in figure , when the vertical lines appear to the eye to be at a considerable angle one to the other, although they are parallel. the lines in sectional shading or cross-hatching may be made to denote the material of which the piece is to be composed. thus professor unwin has proposed the system shown in the figures and . this may be of service in some cases, but it would involve very much more labor than it is worth in ordinary machine shop drawings, except in the case of cast iron and wood, these two being shown in the simplest and the usual manner. it is much better to write the name of the material beneath the piece in a detail drawing. [illustration: fig. .] [illustration: fig. .] line shading. mechanical drawings are made to look better and to show more distinctly by being line shaded or shaded by lines. the simplest form of line shading is by the use of the shade or shadow line. in a mechanical drawing the light is supposed, for the purposes of line shading or of coloring, to come in from the upper left-hand corner of the drawing paper; hence it falls directly upon the upper and left-hand lines of each piece, which are therefore represented by fine lines, while the right hand and lower edges of the piece being on the shadow side may therefore, with propriety, be represented by broader lines, which are called shadow or shade lines. these lines will often serve to indicate the shape of some part of the piece represented, as will be seen from the following examples. in figure is a piece that contains a hole, the fact being shown by the circle being thickened at a. if the circle were thickened on the other side as at b, in figure , it would show that it represented a cylindrical stem instead of a hole. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] in figure is represented a washer, the surfaces that are in the shadow side being shown in a shade line or shadow line, as it is often called. in figure is a key drawn with a shade line, while in figure the shade line is shown applied to a nut. the shade line may be produced in straight lines by drawing the line twice over, and slightly inclining the pen, or by opening the pen points a little. for circles, however, it may be produced either by slightly moving the centre from which the circle is drawn, or by going over the shade part twice, and slightly pressing the instrument as it moves, so as to gradually spring the legs farther apart, the latter plan being generally preferable. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] figure shows a german pen, that can be regulated to draw lines of various breadths. the head of the adjusting screw is made rather larger than usual, and is divided at the under side into twenty divisional notches, each alternate notch being marked by a figure on the face. by this arrangement a uniform thickness of line may be maintained after filling or clearing the pen, and any desired thickness may be repeated, without any loss of time in trial of thickness on the paper. a small spring automatically holds the divided screw-head in any place. with very little practice the click of the spring in the notches becomes a sufficient guide for adjustment, without reference to the figures on the screw-head. another meritorious feature of this pen is that it is armed with sapphire points, which retain their sharpness very long, and thus save the time and labor required to keep ordinary instruments in order for the performance of fine work. an example of line shading in perspective drawing is shown in the drawing of a pipe threading stock and die in figure . [illustration: fig. .] shading by means of lines may be used with excellent effect in mechanical drawing, not only to distinguish round from flat surfaces, but also to denote to the eye the relative distances of surfaces. figure represents a cylindrical pin line shaded. as the light is supposed to come in from the upper left-hand corner, it will evidently fall more upon the left-hand half of the stem, and of the collar or bead, hence those parts are shaded with lighter or finer lines than the right-hand sides are. [illustration: fig. .] [illustration: fig. .] two cylindrical pieces that join each other may be line shaded at whatever angle they may join. figure represents two such pieces, one at a right angle to the other, both being of equal diameter. [illustration: fig. .] figure represents a drawing of a lathe centre shaded by lines, the lines on the taper parts meeting those on the parallel part a, and becoming more nearly parallel to the axis of the piece as the centre of the piece is approached. the same is the case where a piece having a curved outline is drawn, which is shown in figure , where the set of the bow-pen is gradually increased for drawing the shade lines of the curves. the centres of the shade curves fall in each case upon a line at a right angle to the axis of the piece, as upon the lines a, b, c, the dotted lines showing the radius for each curve. [illustration: fig. .] the lines are made finer by closing the pen points by means of the screw provided for that purpose. the pen requires for this purpose to be cleaned of the ink that is apt to dry in it. in figure line shading is shown applied to a ball or sphere, while in figure it is shown applied to a pin in a socket which is shown in section. by showing the hollow in connection with the round piece, the difference between the two is quite clearly seen, the light falling most upon the upper half of the pin and the lower half of the hole. this perhaps is more clearly shown in the piece of tube in figure , where the thickness of the tube showing is a great aid to the eye. so, likewise, the hollow or hole is more clearly seen where the piece is shown in section, as in figure , which is the case even though the piece be taper as in the figure. if the body be bell-mouthed, as in figure , the hollow curve is readily shown by the shading; but to line shade a hollow curve without any of these aids to the eye, as say, to show a half of a tin tube, is a very difficult matter if the piece is to look natural; and all that can be done is to shade the top darkly and let the light fall mostly at and near the bottom. an example of line shading to denote the relative distances from the eye of various surfaces is given in figure , where the surfaces most distant are the most shaded. the flat surfaces are lined with lines of equal breadth, the degrees of shading being governed by the width apart of the lines. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] line shading is often used to denote that the piece represented is to be of wood, the shade lines being in some cases regular in combination with regular ones, or entirely irregular, as in figure . [illustration: fig. .] chapter v. _marking dimensions._ the dimensions of mechanical drawings are best marked in red ink so that they will show plainly, and that the lines denoting the points at which the dimension is given shall not be confounded with the lines of the drawing. the dimension figures should be as large as the drawing will conveniently admit; and should be marked at every point at which a shoulder or change of form or dimension occurs, except in the case of straight tapers which have their dimensions marked at each end of the taper. in the case of a single piece standing by itself the dimension figures may be marked all standing one way, so as to be read without changing the position of the operator or requiring to turn the drawing around. this is done in figure , which represents the drawing of a key. the figures are here placed outside the drawing in all cases where it can be done, which, in the case of a small drawing, leaves the same clearer. [illustration: fig. .] in figure the dimensions are marked, running parallel to the dimension for which they are given, so that all measures of length stand lengthwise, and those of breadth across the drawing. [illustration: fig. .] figure represents a key with a sharp-cornered step in it. here the two dimensions forming the steps cannot both be coincident with it; hence they are marked as near to it as convenient, it being understood that they apply to the step, and not to one side of it. when the step has a round instead of a sharp corner, the radius of the arc of the corner may be marked, as shown in figure . [illustration: fig. .] figure represents a key drawn in perspective, so that all the dimensions may be marked on one view. perspective sketches may be used for single pieces, as they denote the shape of the piece more clearly to the eye. on account of the skill required in their production, they are not, however, used in mechanical drawing, except as in the case of patent-office or similar drawings, where the form and construction rather than the dimension is the information sought to be conveyed. [illustration: fig. .] [illustration: fig. .] chapter vi. _the arrangement of different views._ the different views of a mechanical drawing. the word _elevation_, as applied to mechanical drawing, means simply a view; hence a side elevation is a side view, or an end elevation is an end view. the word _plan_ is employed in place of the word top; hence a plan view is a top view, or a view looking down upon the top of the piece. a _general_ view means a view showing the machine put together or assembled, while a detail drawing is one containing a detail, as a part of the machine or a single piece disconnected from the other parts of the whole machine. it is obviously desirable in a mechanical drawing to present the piece of work in as few views as possible, but in all cases there must be a sufficient number to permit of the dimensions in every necessary direction to be marked on the drawing. suppose, then, that in figure we have to represent a solid cylinder, whose length equals its diameter, and it is obvious that both the diameter and length may be marked in the one view given; hence, a second view, such as shown by the circle in figure , is unnecessary, except it be to distinguish the body from a cube, in which the one view would also be sufficient whereon to mark all the dimensions necessary to enable the piece to be made. it happens, however, that a cube and a cylinder are the only two figures upon which all the dimensions can be marked on one view of the piece, and as cylindrical pieces are much more common in machine work than cubes are, it is taken for granted that, where the pieces are cylindrical, but one view shall be used, and that where they are cubes either two views shall be given, or where they are square a cross shall be marked upon the parts that are square; thus, in figure , is shown a cross formed by the lines a b across the face of the drawing, which saves making a second view. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] it would appear that under some conditions this might lead to error; as, for example, take the piece in figure , and there is nothing to denote which is the length and which is the diameter of the piece, but there is a certain amount of custom in such cases than will usually determine this point; thus, the piece will be given a name, as pin or disk, the one denoting that its diameter is less than its length, and the other that its diameter is greater than its length. in the absence of any such name, it would be in practice assumed that it was a pin and not a disk; because, if it were a disk, it would either be named or shaded, or a second view given to show its unusual form, the disk being a more unusual form than the pin-form in mechanical structures. as an example of the use of the cross to denote a square, we have figure , which represents a piece having a hexagon head, section _a_, _a'_, that is rectangular, a collar _b_, a square part _c_, and a round stem _d_. here it will be noted that it is the rectangular part _a_, _a'_, that renders necessary two views, and that in the absence of the cross, yet another view would be necessary to show that part _c_ is square. [illustration: fig. .] [illustration: fig. .] a rectangular piece always requires two views and sometimes three. in figure , for example, is a piece that would require a side view to show the length and breadth, and an edge view to show the thickness. suppose the piece to be wedge-shaped in any direction; then another view will be necessary, as is shown in figs. and . in the former the wedge or taper is in the direction of its length, while in the latter it is in the direction of its thickness. outline views, however, will not in some cases show the form of the figure, however many views be presented. an example of this is given in figure , which represents a ring having a hexagon cross section. a sectional edge view is here necessary in order to show the hexagonal form. another example of this kind, which occurs more frequently in practice, is a cupped ring such as shown in figure . [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] examples. let it be required to draw a rectangular piece such as is shown in two views in figure , and the process for the pencil lines is as follows: [illustration: fig. .] with the bow-pencil set to half the required length and breadth of the square the arcs , , and , in figure , are marked, and then the lines and , letting them run past the width of the arcs and . there is no need to pencil in lines and , since they can be inked in without pencilling, because it is known that they must meet the arcs and and terminate at the lines and . the top and bottom lines of the edge view are merely prolongations of lines and ; hence the lines and are drawn the requisite distance apart for the thickness and to meet the top and bottom lines. the lines are then inked in, the pencil lines rubbed out, and the drawing will appear as in figure . [illustration: fig. .] [illustration: fig. .] suppose, however, that the piece has a step in it, as in figure , and the pencilling will be as in figure . from the centre, the arcs , , and for the outer, and arcs , , and for the inner square are marked; lines and , and their prolongations, and , for the edge view, are then pencilled; lines and , and their prolongations, and , are then pencilled, and dots to show the locations for lines and maybe marked and the pencilling is complete. lines , , , , , , and may then be inked in, in the order named, and then lines , , , , , , and , when the inking in will be complete. [illustration: fig. .] in inking in horizontal lines begin at the top and mark in each line as the square comes to it; and in inking the vertical ones begin always at the left hand line and mark the lines as they are come to, moving the square or the triangle to the right, and great care should be taken not to let the lines cross where they meet, as at the corners, since this would greatly impair the appearance of the drawing. these figures have been drawn without the aid of a centre line, because from their shapes it was easy to dispense with it, but in most cases a centre line is necessary; thus in figure we have a body having a number of steps. the diameters of these steps are marked by arcs, as in the previous examples, and their lengths may be marked by applying the measuring rule direct to the drawing paper and making the necessary pencil mark. but it would be tedious to mark the successive steps true one with the other by measuring each step, because one step would require to be pencilled in before the next could be marked. to avoid this the centre line , figure , is first marked, and the arcs for the steps are then marked as shown. centre lines are also necessary to show the alignment of one part to another; thus in figure is a cube with a hole passing through it. the dotted lines in the side view show that the hole passes clear through the piece and is a parallel one, while the centre line, being central to the outline throughout the piece, shows that the hole is equidistant, all through, from the walls of the piece. [illustration: fig. .] [illustration: fig. .] the pencil lines for this piece would be marked as in figure , line representing the centre line from which all the arcs are marked. it will be noted that the length of the piece is marked by arcs which occur, because being a cube the set of the compasses for arcs , , and will answer without altering to mark arcs and . [illustration: fig. .] if the hole in the piece were a taper or conical one, it would be denoted by the dotted lines, as in figure , and that the taper is central to the body is shown by these dotted lines being equidistant from the centre line. [illustration: fig. .] suppose one of the sides to be tapered, as is the side a, in figure , and that the hole is not central, and both facts will be shown by the centre lines and in the figure. the measurement of face a would be marked from a to line b at each end, but the distance the hole was out of the centre would be marked by the distance between the centre line and the edge c of the piece. [illustration: fig. .] if the hole did not pass entirely through the piece, the dotted lines would show it, as in figure . [illustration: fig. .] [illustration: fig. .] the designations of the views of a piece of work depend upon the position in which the piece stands, when in place upon the machine of which it forms a part. thus in figure is a lever, and if its shaft stood horizontal when the piece is in place in the machine, the view given is an end one, but suppose that the shaft stood vertical, and the same view becomes a plan or top view. [illustration: fig. .] [illustration: fig. .] in figure is a view of a lever which is a side view if the lever stands horizontal, and lever b hangs down, or a plan view if the shaft stands horizontal, but lever b stands also horizontal. we may take the same drawing and turn it around on the paper as in figure , and it becomes a side view if the shaft stands vertical, and a plan view if the shaft stands horizontal and arm d vertical above it. in a side or an end view, the piece that projects highest in the drawing is highest when upon the machine; also in a side elevation the piece that is at the highest point in the drawing extends farthest upward when the piece is on the machine. but in a plan or top view the height of vertical pieces is not shown, as appears in the case of arm d in figure . [illustration: fig. .] in either of the levers, figures or , all the dimensions could be marked if an additional view were given, but this will not be the case if an eye have a slot in it, as at e, in figure , or a jaw have a tongue in it, as at f: hence, end views of the eye and the jaw must be given, which may be most conveniently done by showing them projected from the ends of those parts as in the figure. this naturally brings us to a consideration as to the best method of projecting one view from another. as a general rule, the side elevation or side view is the most important, because it shows more of the parts and details of the work; hence it should be drawn first, because it affords more assistance in drawing the other views. [illustration: fig. .] there are two systems of placing the different views of a piece. in the first the views are presented as the piece would present itself if it were laid upon the paper for the side view, and then turned or rolled upon the paper for the other views, as shown in figure , in which the piece consists of five sections or members, marked respectively a, b, c, d, and e. now if the piece were turned or rolled so that the end face of b were uppermost, and the member e was beneath, it will, by the operation of turning it, have assumed the position in the lower view marked position ; while if it were turned over upon the paper in the opposite direction it would assume the position marked . this gives to the mind a clear idea of the various views and positions; but it possesses some disadvantages: thus, if position is a side elevation or view of the piece, as it stands when in place of the machine, then e is naturally the bottom member; but it is shown in the top view of the drawing, hence what is actually the bottom view of the piece (position ) becomes the top view in the drawing. a second disadvantage is that if we desire to put in dotted lines, to show how one view is derived from the other, and denote corresponding parts, then these dotted lines must be drawn across the face of the drawing, making it less distinct; thus the dotted lines connecting stem e in position to e in position , pass across the faces of both a and b of position . [illustration: fig. .] [illustration: fig. .] in a large drawing, or one composed of many members or parts, it would, therefore, be out of the question to mark in the dotted lines. a further disadvantage in a large drawing is that it is necessary to go from one side of the drawing to the other to see the construction of the same part. [illustration: fig. .] to obviate these difficulties, a modern method is to suppose the piece, instead of rolling upon the paper, to be lifted from it, turned around to present the required view, and then moved upwards on the paper for a top view, sideways for a side view, and below for a bottom view. thus the three views of the piece in figure would be as in figure , where position is obtained by supposing the piece to be lifted from position , the bottom face turned uppermost, and the piece moved down the paper to position , which is a bottom view of the piece, and the bottom view in the drawing. similarly, if the piece be lifted from position , and the top face in that figure is turned uppermost, and the piece is then slid upwards on the paper, view is obtained, being a top view of the piece as it lies in position , and the top view in the drawing. now suppose we require to find the shape of member b, then in figure we require to look at the top of position , and then down below to position . [illustration: fig. .] but in figure we have the side view and end view both together, while the dotted lines do not require to cross the face of the side view. now suppose we take a similar piece, and suppose its end faces, as f, g, to have holes in them, which require to be shown in both views, and under the one system the drawing would, if the dotted lines were drawn across, appear as in figure , whereas under the other system the drawing would appear as in figure . and it follows that in cases where it is necessary to draw dotted lines from one view to the other, it is best to adopt the new system. chapter vii. _examples in bolts, nuts, and polygons._ [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] let it be required to draw a machine screw, and it is not necessary, and therefore not usual in small screws to draw the full outline of the thread, but to represent it by thick and thin lines running diagonally across the bolt, as in figure , the thick ones representing the bottom, and the thin ones the top of the thread. the pencil lines would be drawn in the order shown in figure . line is the centre line, and line a line to represent the lower side of the head; from the intersection of these two lines as a centre (as at a) short arcs and , showing the diameter of the thread, are marked, and the arcs and , representing the depth of the thread, are marked. the arc , representing the head, is then marked. the vertical lines , , , and are then marked, and the outline of the screw is complete. the thick lines representing the bottom of the thread are next marked in, as in figure , extending from line to line . midway between these lines fine ones are made for the tops of the thread. all the lines being pencilled in, they may be inked in with the drawing instruments, taking care that they do not overrun one another. when the pencil lines are rubbed out, the sketch will appear as in figure . [illustration: fig. .] for a bolt with a hexagon head the lines would be drawn in the order shown in figure . at a right-angle to centre line , line two is drawn. the pencil-compasses are then set to half the diameter of the bolt, and from point a arcs and are pencilled, thus showing the width of the front flat of the head, as well as the diameter of the stem. from the point where these arcs meet line , and with the same radius, arcs and are marked, showing the widths of the other two flats of the head. the thickness of the head and the length of the bolt head may then be marked either by placing a rule on line and marking the short lines (such as line ) a cross line , or the pencil-compasses may be set to the rule and the lengths marked from point a. in the united states standard for bolt heads and nuts the thickness of the head is made equal to the diameter of the bolt. with the compasses set for the arcs and , we may in two steps, from a along the centre line, mark off the thickness of the head without using the rule. but as the rule has to be applied along line to mark line for the length of the bolt, it is just as easy to mark the head thickness at the same time. the line showing the length of the thread may be marked at the same time as the other lengths are marked, and the outlines , , , , may be drawn in the order named. we have now to mark the arcs at the top of the flats of the head to show the chamfer, and to explain how these arcs are obtained we have in figure an enlarged view of the head. it is evident that the smallest diameter of the chamfer is represented by the circle a, and therefore the length of the line b must equal a. it is also evident that the outer edge of the chamfer will meet the corners at an equal depth (from the face of the nut), as represented by the line c c, and it is obvious that the curves that represent the outline of the chamfer on each side of the head or nut will approach the face of the head or nut at an equal distance, as denoted by the line d d. it follows that the curve must in each case be such as will, at each of its ends, meet the line c, and at its centre meet the line d d, the centres of the respective curves being marked in the figure by x. [illustration: fig. .] it is sufficiently accurate, therefore, for all practical purposes to set the pencil on the centre-line at the point a in figure and mark the curve , and to then set the compasses by trial to mark the other two curves of the chamfer, so that they shall be an equal distance with arc from line , and join lines and at the same distance from line that joins lines and , so that as in figure all three of the arcs would touch a line as c, and another line as d. [illustration: fig. .] the united states standard sizes for forged or unfinished bolts and nuts are given in the following table, figure showing the dimensions referred to in the table. united states standard dimensions of bolts and nuts. key: a: nominal. d. b: effective.[*] c: standard number of threads per inch. ------------------------+----------------------------+--------------------- bolt. | bolt head and nut. | ------------------------+-----------------+----------+----------+---------- diameter. | | long diameter, | short | | -------+------| | i, or diameter | diameter | | | | | across corners. | of | | | | |--------+--------| hexagon | | a | b | c | hexa- | square.| and | | | | | gon. | | square, | depth of | depth of | | | | | or width | nut, | bolt | | | | | across j.| h. | head, k. -------+------+---------+--------+--------+----------+----------+---------- / | . | | / | / | / | / | / / | . | | / | / | / | / | / / | . | | / | / | / | / | / / | . | | / | - / | / | / | / / | . | | | - / | / | / | / / | . | | - / | - / | / | / | / / | . | | - / | - / | - / | / | / / | . | | - / | - / | - / | / | / / | . | | - / | - / | - / | / | / | . | | - / | - / | - / | | / - / | . | | - / | - / | - / | - / | / - / | . | | - / | - / | | - / | - / | . | | - / | - / | - / | - / | - / - / | . | | - / | - / | - / | - / | - / - / | . | - / | - / | - / | - / | - / | - / - / | . | | - / | - / | - / | - / | - / - / | . | | - / | - / | - / | - / | - / | . | - / | - / | - / | - / | | - / - / | . | - / | - / | - / | - / | - / | - / - / | . | | - / | - / | - / | - / | - / - / | . | | - / | | - / | - / | - / | . | - / | - / | - / | - / | | - / - / | . | - / | - / | - / | | - / | - / - / | . | - / | - / | - / | - / | - / | - / - / | . | | - / | - / | - / | - / | - / ... | . | | - / | - / | - / | | - / - / | . | - / | - / | - / | - / | - / | - / - / | . | - / | - / | - / | - / | - / | - / - / | . | - / | - / | - / | - / | - / | - / | . | - / | - / | - / | - / | | - / - / | . | - / | - / | - / | | - / | - / | . | - / | - / | - / | - / | - / | - / - / | . | - / | - / | - / | - / | - / | - / | . | - / | - / | - / | - / | | - / -------+------+---------+--------+--------+----------+----------+---------- * diameter at the root of the thread. the basis of the franklin institute or united states standard for the heads of bolts and for nuts is as follows: the short diameter or width across the flats is equal to one and one-half times the diameter plus / inch for rough or unfinished bolts and nuts, and one and one-half times the bolt diameter plus, / inch for finished heads and nuts. the thickness is, for rough heads and nuts, equal to the diameter of the bolt, and for finished heads and nuts / inch less. [illustration: fig. .] [illustration: fig. .] the hexagonal or hexagon (as they are termed in the shop) heads of bolts may be presented in two ways, as is shown in figures and . the latter is preferable, inasmuch as it shows the width across the flats, which is the dimension that is worked to, because it is where the wrench fits, and therefore of most importance; whereas the latter gives the length of a flat, which is not worked to, except incidentally, as it were. there is the objection to the view of the head, given in figure , however, that unless it is accompanied by an end view it somewhat resembles a similar view of a square head for a bolt. it may be distinguished therefrom, however, in the following points: if the amount of chamfer is such as to leave the chamfer circle (as circle a, in figure ) of smaller diameter than the width across the flats of the bolt-head, the outline of the sides of the head will pass above the arcs at the top of the flats, and there will be two small flat places, as a and b, in figure (representing the angle of the chamfer), which will not meet the arcs at the top of the flats, but will join the sides above those arcs, as in the figure; which is also the case in a similar view of a square-headed bolt. it may be distinguished therefrom, however, in the following points: if the amount of chamfer is such as to leave the chamfer circle (a, figure ) of smaller diameter than the width across the flats of the bolt-head, the outline of the sides will pass above the arc on the flats, as is shown in figure , in which the chamfer a meets the side of the head at b, and does not, therefore, meet the arc c. the length of side lying between b and d in the side view corresponds with the part lying between e and f in the end view. [illustration: fig. .] if we compare this head with similar views of a square head g, both being of equal widths, and having their chamfer circles at an equal distance from the sides of the flats, and at the same angle, we perceive at once that the amount of chamfer necessary to give the same distance between the chamfer circle and the side of the bolt (that is, the distance from j to k, being equal to that from l to m), the length of the chamfer n for the square head so greatly exceeds the length a for the hexagon head that the eye detects the difference at once, and is instinctively informed that g must be square, independently of the fact that in the case of the square head, n meets the arc o, while in the hexagon head, a, which corresponds to n, does not meet the arc c, which corresponds to o. when, however, the chamfer is drawn, but just sufficient to meet the flats, as in the case of the hexagon h, and the square i, in figure , the chamfer line passes from the chamfer circle to the side of the head, and the distinction is greater, as will be seen by comparing head h with head i, both being of equal width, having the same angle of chamfer, and an amount just sufficient to meet the sides of the flats. here it will be seen that in the hexagon h, each side of the head, as p, meets the chamfer circle a. whereas, in the square head these two lines are joined by the chamfer line q, the figures being quite dissimilar. [illustration: fig. .] it is obvious that whatever the degree or angle of the chamfer may be, the diameter of the chamfer circle will be the same in any view in which the head may be presented. thus, in figure , the line g in the side view is in length equal to the diameter of circle g, in the end view, and so long as the angle of the chamfer is forty-five degrees, as in all the views hitherto given, the width of the chamfer will be equal at corresponding points in the different views; thus in the figure the widths a and b in the two views are equal. [illustration: fig. .] if the other view showing a corner of the head in front of the head be given, the same fact holds good, as is shown in figure . that the two outside flats should appear in the drawing to be half the width of the middle flat is also shown in figure , where d and e are each half the width of c. let us now suppose, that the chamfer be given some other angle than that of degrees, and we shall find that the effect is to alter the curves of the chamfer arcs on the flats, as is shown in figure , where these arcs e, c, d are shown less curved, because the chamfer b has more angle to the flats. as a result, the width or distance between the arcs and line g is different in the two views. on this account it is better to draw the chamfer at degrees, as correct results may be obtained with the least trouble. if no chamfer at all is to be given, a hexagon head may still be distinguished from a square one, providing that the view giving three sides of the head, as in figure , is shown, because the two sides d and e being half the width of the middle one c, imparts the information that it is a hexagon head. if, however, the view showing but two of the sides and a corner in front is given, and no chamfer is used, it could not be known whether the head was to be hexagon or square, unless an end view be given, as in figure . [illustration: fig. .] if the view showing a full side of the head of a square-headed bolt is given, then either an end view must be given, as in figure , or else a single view with a cross on its head, as in figure , may be given. it is the better plan, both in square and hexagon heads, to give the view in which the full face of a flat is presented, that is, as in figures and ; because, in the case of the square, the length of a side and the width across the head are both given in that view; whereas if two sides are shown, as in figure , the width across flats is not given, and this is the dimension that is wanted to work to, and not the width across corners. in the case of a hexagon the middle of the three flats is equal in width to the diameter of the bolt, and the other two are one-half its width; all three, therefore, being marked with the same set of compasses as gives the diameter of the body of the bolt, were as shown in figure . for the width across flats there is an accepted standard; hence there is no need to mark it upon the drawing, unless in cases where the standard is to be departed from, in which event an end view may be added, or the view showing two sides may be given. [illustration: fig .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] to draw a square-headed bolt, the pencil lines are marked in the order shown by figures in figure . the inking in is done in the order of the letters _a_, _b_, _c_, etc. it will be observed that pencil lines , , and are not drawn to cross, but only to meet the lines at their ends, a point that, as before stated, should always be carefully attended to. [illustration: fig. ] to draw the end view of a hexagon head, first draw a circle of the diameter across the flats, and then rest the triangle of degrees on the blade _s_ of the square, as at t , in figure , and mark the lines _a_ and _b_. reverse the triangle, as at t , and draw lines _c_ and _d_. then place the triangle as in figure , and draw the lines _e_ and _f_. [illustration: fig. .] if the other view of the head is to be drawn, then first draw the lines _a_ and _b_ in figure with the square, then with the degree triangle, placed on the square s, as at t , draw the lines _c_, _d_, and turning the square over, as at t , mark lines _e_ and _f_. [illustration: fig. .] if the diameter across corners of a square head is given, and it be required to draw the head, the process is as follows: for a view showing one corner in front, as in figure , a circle of the given diameter across corners is pencilled, and the horizontal centre-line _a_ is marked, and the triangle of degrees is rested against the square blade s, as in position t , and lines _b_ and _c_ marked, _b_ being marked first; and the triangle is then slid along the square blade to position t , when line _c_ is marked, these two lines just meeting the horizontal line _a_, where it meets the circle. the triangle is then moved to the left, and line _d_, joining the ends of _b_ and _c_, is marked, and by moving it still farther to the left to position t , line _e_ is marked. lines _b_, _c_, _d_, and _e_ are, of course, the only ones inked in. [illustration: fig. .] [illustration: fig. .] if the flats are to lie in the other direction, the pencilling will be done as in figure . the circle is marked as before, and with the triangle placed as shown at t , line _a_, passing through the centre of the circle, is drawn. by moving the triangle to the right its edge b will be brought into position to mark line _b_, also passing through the centre of the circle. all that remains is to join the ends of these two lines, using the square blade for lines _c_, _d_, and the triangle for _e_ and _f_, its position on the square blade being denoted at t ; lines _c_, _d_, _e_, _f_, are the ones inked in. [illustration: fig. .] for a hexagon head we have the processes, figures and . the circle is struck, and across it line _a_, figure , passing through its centre, the triangle of sixty degrees will mark the sides _b_, _c_, and _d_, _e_, as shown, and the square blade is used for _f_, _g_. [illustration: fig. .] the chamfer circles are left out of these figures to reduce the number of lines and so keep the engraving clear. figure shows the method of drawing a hexagon head when the diameter across corners is given, the lines being drawn in the alphabetical order marked, and the triangle used as will now be understood. [illustration: fig. .] [illustration: fig. .] it may now be pointed out that the triangle may be used to divide circles much more quickly than they could be divided by stepping around them with compasses. suppose, for example, that we require to divide a circle into eight equal parts, and we may do so as in figure , line _a_ being marked from the square, and lines _b_, _c_ and _d_ from the triangle of forty-five degrees; the lines to be inked in to form an octagon need not be pencilled, as their location is clearly defined, being lines joining the ends of the lines crossing the circle, as for example, lines _e_, _f_. let it be required to draw a polygon having twelve equal sides, and the triangle of sixty is used, marking all the lines within the circle in figure , except _a_, for which the square blade is used; the only lines to be inked in are such as _b_, _c_. in this example there is a corner at the top and bottom, but suppose it were required that a flat should fall there instead of a corner; then all we have to do is to set the square blade s at the required angle, as in figure , and then proceed as before, bearing in mind that the point of the circle nearest to the square blade, straight-edge, or whatever the triangle is rested on, is always a corner of a polygon having twelve sides. [illustration: fig. .] [illustration: fig. .] in both of these examples we have assumed that the diameter across corners of the polygon was given, but suppose the diameter across the flats were given, and the construction is a little more complicated. circle _a_, _a_, in figure , is drawn of the required diameter across the flats, and the lines of division are drawn across with the triangle of as before; the triangle of is then used to draw the four lines, _b_, _c_, _d_, _e_, joining the ends of lines _i_, _j_, _k_, _l_, and touching the inner circle, _a_, _a_. the outer circle is then pencilled in, touching the lines of division where they meet the lines _b_, _c_, _d_, _e_, and the rest of the lines for the sides of the polygon may then be drawn within the outer circle, as at _g_, _h_. [illustration: fig. .] it is obvious, also, that the triangle may be used to draw slots radiating from a centre, as in figure , where it is desired to draw a chuck-plate having slots. the triangle of is used to draw the centre lines, _a_, _b_, _c_, etc., for the slots. from the centre, the arcs _e_, _f_, _g_, _h_, etc., are marked, showing where the centres will fall for describing the half circles forming the ends of the slots. then half circles, _i_, _j_, _k_, _l_, etc., being drawn, the sides of the slots may be drawn in with the triangle, and the outer circle and the slots inked in. if the slots are not to radiate from the centre of the circle the process is as follows: the outer circle _a_, figure , being drawn, an inner one _b_ is drawn, its radius equalling the amount; the centres of the slots are to point to one side of the centre of circle _a_. the triangle is then used to divide the circle into the requisite number of divisions _c_ for the slots, and arcs _i, j_, are then drawn for the lengths of the slots. the centre lines _e_ are then drawn, passing through the lines _c_, and the arcs _i, j_, etc., and touching the perimeter of the inner circle _b_; arcs _f, g_, are then marked in, and their sides joined with the triangle adjusted by hand. all that would be inked in black are the outer circle and the slots, but the inner circle _b_ and a centre line of one of the slots should be marked in red ink to show how the inclination of the slot was obtained, and therefore its amount. [illustration: fig. .] for a five-sided figure it is best to step around the circumference of the circle with the compasses, but for a three-sided one, or trigon, the construction is as follows: it will be found that the compasses set to the radius of a circle will accurately divide it into six equal divisions, as is shown in figure ; hence every other one of these divisions will be the location for a corner of a trigon. the circle being drawn, a line a, , is drawn through its centre, and from its intersection with the circle as at _b_, here a step on each side is marked as _c_, _d_, then lines _c_ to _d_, and _c_ and _d_ to _e_, where a meets, the circle will describe a trigon. if the figure is to stand vertical, all that is necessary is to draw the line _a_ vertical, as in figure . a ready method of getting the dimension across corners, across the flats, or the length of a side of a given polygon, is by means of diagrams, such as shown in the following figures, which form excellent examples for practice. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] draw the line o p, figure , and at a right angle to it the line o b; divide these two lines into parts of one inch, as shown in the cut, which is divided into inches and quarter inches, and from these points of division draw lines crossing each other as shown. [illustration: fig. .] from the point o, draw diagonal lines, at suitable angles to the line o p. as shown in the cut, these diagonal lines are marked: degrees for sided figures. " " " " " " " " - / " " " " - / " " " " but still others could be added for figures having a greater number of sides. . now it will be found as follows: half the diameter, or the radius of a piece of cylindrical work being given, and the number of sides it is to have being stated, the length of one side will be the distance measured horizontally from the line o b to the diagonal line for that particular number of sides. example.--a piece of work is - / inches in diameter, and is required to have sides: what will be the length of the sides or flats? now the half diameter or radius of - / inches is - / inches. then look along the line o b for - / , which is denoted in the cut by figures and the arrow a; set one point of the compasses at a, and the other at the point of crossing of the diagonal line with the - / horizontal line, as shown in the figure at _a_, and from a to _a_ is the length of one side. again: a piece of work, inches in diameter, is to have sides: how long will each side be? now half of is , hence from b to _b_ is the length of each side. but suppose that from the length of each side, and the number of sides, it is required to find the diameter to which to turn the piece; that is, its diameter across corners, and we simply reverse the process thus: a body has sides, each side measures / : what is its diameter across corners? take a rule, apply it horizontally on the figure, and pass it along till the distance from the line o b to the diagonal line marked sides measures / , which is from - / on o b to _a_, and the - / is the radius, which, multiplied by , gives - / inches, which is the required diameter across corners. for any other number of sides the process is just the same. thus: a body is - / inches in diameter, and is to have sides: what will be the length of each side? now half of - / is - / ; hence from - / on the line o b to the point c, where the diagonal line crosses the - / line, is the length of each of the sides. . it will be found that the length of a side of a square being given, the size of the square, measured across corners, will be the length of the diagonal line marked degrees, from the point o to the figures indicating, on the line o b or on the line o p, the length of one side. example.--a square body measures inch on each side: what does it measure across the corners? answer: from the point o, along diagonal line marked degrees, to the point where it crosses the lines (as denoted in the figure by a dot). again: a cylindrical piece of wood requires to be squared, and each side of the square must measure an inch: what diameter must the piece be turned to? now the diagonal line marked degrees passes through the -inch line on o b, and the inch line on o p, at the point where these lines meet; hence all we have to do is to run the eye along either of the lines marked inch, and from its point of meeting the degrees line, to the point o, is the diameter to turn the piece to. there is another way, however, of getting this same measurement, which is to set a pair of compasses from the line on o b, to line on o p, as shown by the line d, which is the full diameter across corners. this is apparent, because from point o, along line o b, to , thence to the dot, thence down to line on o p, and along that to o, encloses a square, of which either from o to the dot, or the length of the line d, is the measurement across corners, while the length of each side, or diameter across the flats, is from point o to either of the points , or from either of the points to the dot. [illustration: fig. .] after graphically demonstrating the correctness of the scale we may simplify it considerably. in figure , therefore, we have applications shown. a is a hexagon, and if one of its sides be measured, it will be found that it measures the same as along line from o b to the diagonal line degrees, which distance is shown by a thickened line. at - / is shown a seven-sided figure, whose diameter is inches, and radius - / inches, and if from the point at - / (along the thickened horizontal line), to the diagonal marked degrees, be measured, it will be found exactly equal to the length of a side on the polygon. at c is shown part of a nine-sided polygon, of -inch radius, and the length of one of its sides will be found to equal the distance from the diagonal line marked - / degrees, and the line o b at . let it now be noted that if from the point o, as a centre, we describe arcs of circles from the points of division on o b to o p, one end of each arc will meet the same figure on o p as it started from at o b, as is shown in figure , and it becomes apparent that in the length of diagonal line between o and the required arc we have the radius of the polygon. example.--what is the radius across corners of a hexagon or six-sided figure, the length of a side being an inch? turning to our scale we find that the place where there is a horizontal distance of an inch between the diagonal degrees, answering to six-sided figures, is along line (figure ), and the radius of the circle enclosing the six-sided body is, therefore, an inch, as will be seen on referring to circle a. but it will be noted that the length of diagonal line degrees, enclosed between the point o and the arc of circle from on o b to one on o p, measures also an inch. hence we may measure the radius along the diagonal lines if we choose. this, however, simply serves to demonstrate the correctness of the scale, which, being understood, we may dispense with most of the lines, arriving at a scale such as shown in figure , in which the length of the side of the polygon is the distance from the line o b, measured horizontally to the diagonal, corresponding to the number of sides of the polygon. the radius across corners of the polygon is that of the distance from o along o b to the horizontal line, giving the length of the side of the polygon, and the width across corners for a given length of one side of the square, is measured by the length of the lines a, b, c, etc. thus, dotted line shows the length of the side of a nine-sided figure, of -inch radius, the radius across corners of the figure being inches. [illustration: fig. .] the dotted line - / shows the length of the side of a nine-sided polygon, having a radius across corners of - / inches. the dotted line shows the diameter, across corners, of a square whose sides measure an inch, and so on. [illustration: fig. .] this scale lacks, however, one element, in that the diameter across the flats of a regular polygon being given, it will not give the diameter across the corners. this, however, we may obtain by a somewhat similar construction. thus, in figure , draw the line o b, and divide it into inches and parts of an inch. from these points of division draw horizontal lines; from the point o draw the following lines and at the following angles from the horizontal line o p. [illustration: fig. .] a line at ° for polygons having sides. " ° " " " " - / ° " " " " ° " " " from the point o to the numerals denoting the radius of the polygon is the radius across the flats, while from point o to the horizontal line drawn from those numerals is the radius across corners of the polygon. [illustration: fig. .] a hexagon measures two inches across the flats: what is its diameter measured across the corners? now from point o to the horizontal line marked inch, measured along the line of degrees, is - nds inches: hence the hexagon measures twice that, or - ths inches across corners. the proof of the construction is shown in the figure, the hexagon and other polygons being marked simply for clearness of illustration. [illustration: fig. .] [illustration: fig. .] let it be required to draw the stud shown in figure , and the construction would be, for the pencil lines, as shown in figure ; line is the centre line, arcs, and give the large, and arcs and the small diameter, to touch which lines , , , and may be drawn. lines , , and are then drawn for the lengths, and it remains to draw the curves in. in drawing these curves great exactitude is required to properly find their centres; nothing looks worse in a drawing than an unfair or uneven junction between curves and straight lines. to find the location for these centres, set the compasses to the required radius for the curve, and from the point or corner a draw the arcs _b_ and _c_, from _c_ mark the arc _e_, and from _b_ the arc _d_, and where _d_ and _e_ cross is the centre for the curve _f_. [illustration: fig. .] similarly for the curve _h_, set the compasses on _i_ and mark the arc _g_, and from the point where it crosses line , draw the curve _h_. in inking in it is best to draw in all curves or arcs of circles first, and the straight lines that join them afterward, because, if the straight lines are drawn first, it is a difficult matter to alter the centres of the curves to make them fall true, whereas, after the curves are drawn it is an easy matter, if it should be necessary, to vary the line a trifle, so as to make it join the curves correctly and fair. in inking in these curves also, care must be taken not to draw them too short or too long, as this would impair the appearance very much, as is shown in figure . [illustration: fig. .] [illustration: fig. .] to draw the piece shown in figure , the lines are drawn in the order indicated by the letters in figure , the example being given for practice. it is well for the beginner to draw examples of common objects, such as the hand hammer in figure , or the chuck plate in figure , which afford good examples in the drawing of arcs and circles. in figure _a_ is a cap nut, and the order in which the same would be pencilled in is indicated by the respective numerals. the circles and represent the thread. [illustration: fig. _a_.] in figure is shown the pencilling for a link having the hubs on one side only, so that a centre line is unnecessary on the edge view, as all the lengths are derived from the top view, while the thickness of the stem and height of the hubs may be measured from the line a. in figure there are hubs (on both sides of the link) of unequal height, hence a centre line is necessary in both views, and from this line all measurements should be marked. [illustration: fig. .] [illustration: fig. .] in figure are represented the pencil lines for a double eye or knuckle joint, as it is sometimes termed, an example that it is desirable for the student to draw in various sizes, as it is representative of a large class of work. these eyes often have an offset, and an example of this is given in figure , in which a is the centre line for the stem distant from the centre line b of the eyes to the amount of offset required. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] in figure is an example of a connecting rod end. from a point, as a, we draw arcs, as b c for the width, and e d for the length of the block, and through a we draw the centre line. it is obvious, however, that we may draw the centre line first, and apply the measuring rule direct to the paper, and mark lines in place of the arcs b, c, d, e, and f, g, which are for the stem. as the block joins the stem in a straight line, the latter is evidently rectangular, as will be seen by referring to figure , which represents a rod end with a round stem, the fact that the stem is round being clearly shown by the curves a b. the radius of these curves is obtained as follows: it is obvious that they will join the rod stem at the same point as the shoulder curves do, as denoted by the dotted vertical line. so likewise they join the curves e f at the same point in the rod length as the shoulder curves, both curves in fact being formed by the same round corner or shoulder. the centre of the radius of a or b must therefore be the same distance from the centre of the rod as is the centre from which the shoulder curve is struck, and at the same time at such a distance from the corner (as e or f) that the curve will meet the centre line of the rod at the same point in its length as the shoulder curves do. [illustration: fig. .] figure gives an example, in which the similar curved lines show that a part is square. the figure represents a bolt with a square under the head. as but one view is given, that fact alone tells us that it must be round or square. now we might mark a cross on the square part, to denote that it is square; but this is unnecessary, because the curves f g show such to be the case. these curves are marked as follows: with the compasses set to the radius e, one point is rested at a, and arc b is drawn; then one point of the compass is rested at c, and arc d is drawn; giving the centre for the curve f by a similar process on the other side of the figure, curve g is drawn. point c is obtained by drawing the dotted line across where the outline curve meets the stem. suppose that the corner where the round stem meets the square under the head was a sharp one instead of a curve, then the traditional cross would require to be put on the square, as in figure ; or the cross will be necessary if the corner be a round one, if the stem is reduced in diameter, as in figure . [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] figure represents a centre punch, giving an example, in which the flat sides gradually run out upon a circle, the edges forming curves, as at a, b, etc. the length of these curves is determined as follows: they must begin where the taper of the punch joins the parallel, or at c, c, and they must end on that part of the taper stem where the diameter is equal to the diameter across the flats of the octagon. all that is to be done then is to find the diameter across the flats on the end view, and mark it on the taper stem, as at d, d, which will show where the flats terminate on the taper stem. and the curved lines, as a, b, may be drawn in by a curve that must meet at the line c, and also in a rounded point at line d. chapter viii. _screw threads and spirals._ [illustration: fig. .] [illustration: fig. .] the screw thread for small bolts is represented by thick and thin lines, such as was shown in figure , but in larger sizes; the angles of the thread also are drawn in, as in figure , and the method of doing this is shown in figure . the centre line and lines and for the full diameter of the thread being drawn, set the compasses to the required pitch of the thread, and stepping along line , mark the arcs , , , etc., for the full length the thread is to be marked. with the triangle resting against the $t$-square, the lines , , , etc. (for the full length of the thread), are drawn from the points , , , on line . these give one side of the thread. reversing the drawing triangle, angles , , etc., are then drawn, which will complete the outline of the thread at the top of the bolt. we may now mark the depth of the thread by drawing line , and with the compasses set on the centre line transfer this depth to the other side of the bolt, as denoted by the arcs and . touching arc we mark line for the thread depth on that side. we have now to get the slant of the thread across the bolt. it is obvious that in passing once around the bolt the thread advances to the amount of the pitch as from _a_ to _b_; hence, in passing half way around, it will advance from _a_ to _c_; we therefore draw line at a right-angle to the centre line, and a line that touches the top of the threads at _a_, where it meets line , and also meets line , where it touches line , is the angle or slope for the tops of the threads, which may be drawn across by lines, as , , , etc. from these lines the sides of the thread may be drawn at the bottom of the bolt, marking first the angle on one side, as by lines , , , etc., and then the angles on the other, as by lines , , etc. [illustration: fig. .] there now remain the bottoms of the thread to draw, and this is done by drawing lines from the bottom of the thread on one side of the bolt to the bottom on the other, as shown in the cut by a dotted line; hence, we may set a square blade to that angle, and mark in these lines, as , , , etc., and the thread is pencilled in complete. if the student will follow out this example upon paper, it will appear to him that after the thread had been marked out on one side of the bolt, the angle of the thread might be obtained, as shown by lines and , and that the bottoms of the thread as well as the tops might be carried across the bolt to the other side. figure represents a case in which this has been done, and it will be observed that the lines denoting the bottom of the thread do not meet the bottoms of the thread, which occurs for the reason that the angle for the bottom is not the same as that for the top of the thread. [illustration: fig. .] [illustration: fig. .] in inking in the thread, it enhances the appearance to give the bottom of the thread and the right-hand side of the same, heavy shade lines, as in figure , a plan that is usually adopted for threads of large diameter and coarse pitch. a double thread, such as in figure , is drawn in the same way, except that the slant of the thread is doubled, and the square is to be set for the thread-pitch a, a, both for the tops and bottoms of the thread. [illustration: fig .] a round top and bottom thread, as the whitworth thread, is drawn by single lines, as in figure . a left-hand thread, figure , is obviously drawn by the same process as a right-hand one, except that the slant of the thread is given in the opposite direction. for screw threads of a large diameter it is not uncommon to draw in the thread curves as they appear to the eye, and the method of doing this is shown in figure . the thread is first marked on both sides of the bolt, as explained, and instead of drawing, straight across the bolt, lines to represent the tops and bottoms of the thread, a template to draw the curves by is required. to get these curves, two half-circles, one equal in diameter to the top, and one equal to the bottom of the thread, are drawn, as in figure . [illustration: fig. .] these half-circles are divided into any convenient number of equal divisions: thus in figure , each has eight divisions, as _a_, _b_, _c_, etc., for the outer, and _i_, _j_, _k_, etc., for the inner one. the pitch of the thread is then divided off by vertical lines into as many equal divisions as the half-circles are divided into, as by the lines _a_, _b_, _c_, etc., to _o_. of these, the seven from _a_, to _h_, correspond to the seven from _a'_ to _g'_, and are for the top of the thread, and the seven from _i_ to _o_ correspond to the seven on the inner half-circle, as _i_, _j_, _k_, etc. horizontal lines are then drawn from the points of the division to meet the vertical lines of division; thus the horizontal dotted line from _a'_ meets the vertical line _a_, and where they meet, as at a, a dot is made. where the dotted line from _b'_ meets vertical line _b_, another dot is made, as at b, and so on until the point g is found. a curve drawn to pass from the top of the thread on one side of the bolt to the top of the other side, and passing through these points, as from a to g, will be the curve for the top of the thread, and from this curve a template may be made to mark all the other thread-tops from, because manifestly all the tops of the thread on the bolt will be alike. for the bottoms of the thread, lines are similarly drawn, as from _i'_ to meet _i_, where dot i is marked. j is got from _j'_ and _j_, while k is got from the intersection of _k'_ with _k_, and so on, the dots from i to o being those through which a curve is drawn for the bottom of the thread, and from this curve a template also may be made to mark all the thread bottoms. we have in our example used eight points of division in each half-circle, but either more or less points maybe used, the only requisite being that the pitch of the thread must be divided into as many divisions as the two half-circles are. but it is not absolutely necessary that both half-circles be divided into the same number of equal divisions. thus, suppose the large half-circle were divided into ten divisions, then instead of the first half of the pitch being divided into eight (as from _a_ to _h_) it would require to have ten lines. but the inner half-circle may have eight only, as in our example. it is more convenient, however, to use the same number of divisions for both circles, so that they may both be divided together by lines radiating from the centre. the more the points of division, the greater number of points to draw the curves through; hence it is desirable to have as many as possible, which is governed by the pitch of the thread, it being obvious that the finer the pitch the less the number of distinct and clear divisions it is practicable to divide it into. in our example the angles of the thread are spread out to cause these lines to be thrown further apart than they would be in a bolt of that diameter; hence it will be seen that in threads of but two or three inches in diameter the lines would fall very close together, and would require to be drawn finely and with care to keep them distinct. [illustration: fig. _a_.] [illustration: fig. .] the curves for a united states standard form of thread are obtained in the same manner as from the $v$ thread in figure , but the thread itself is more difficult to draw. the construction of this thread is shown in figure , it having a flat place at the top and at the bottom of the thread. a common $v$ thread has its sides at an angle of degrees, one to the other, the top and bottom meeting in a point. the united states standard is obtained from drawing a common $v$ thread and dividing its depth into eight equal divisions, as at _x_, in figure _a_, and cutting off one of these divisions at the top and filling in one at the bottom to form flat places, as shown in the figure. but the thread cannot be sketched on a bolt by this means unless temporary lines are used to get the thread from, these temporary lines being drawn to represent a bolt one-fourth the depth of the thread too large in diameter. thus, in figure _a_, it is seen that cutting off one-eighth the depth of the thread reduces the diameter of the thread. it is necessary, then, to draw the flat place on top of the thread first, the order of procedure being shown in figure . the lines for the full diameter of the thread being drawn, the pitch is stepped off by arcs, as , , , etc.; and from these, arcs, as , , , etc., are marked for the width of the flat places at the tops of the threads. then one side of the thread is marked off by lines, as , which meet the arcs , , , etc., as at _a_, _c_, etc. similar lines, as and , are marked for the other side of the thread, these lines, , and , projecting until they cross each other. line is then drawn, making a flat place at the bottom of the thread equal in width to that at the top. line is then drawn square across the bolt, starting from the bottom of the thread, and line is drawn starting from the corner _f_ on one side of the thread and meeting line on the other side of the thread, which gives the angle for the tops of the thread. the depth of the thread may then be marked on the other side of the bolt by the arcs _d_ and _e_, and the line . the tops of all the threads may then be drawn in, as by lines , , and , and by lines, as , etc., the thread sides may be drawn on the other side of the bolt. all that remains is to join the bottoms of the threads by lines across the bolt, and the pencil lines will be complete, ready to ink in. if the thread is to be shown curved instead of drawn straight across, the curve may be obtained by the construction in figure , which is similar to that in figure , except that while the pitch is divided off into divisions, the whole of these divisions are not used to get the curves, some of them being used twice over; thus for the bottom the eight divisions from _b_ to _i_ are used, while for the tops the eight from _g_ to _o_ are used. hence _g_, _h_ and _i_ are used for getting both curves, the divisions from _a_ to _b_ and from _o_ to _p_ being taken up by the flat top and bottom of the thread. it will be noted that in figure , the top of the thread is drawn first, while in figure the bottom is drawn first, and that in the latter (for the u.s. standard) the pitch is marked from centre to centre of the flats of the thread. [illustration: fig. .] to draw a square thread the pencil lines are marked in the order shown in figure , in which represents the centre line and , , and , the diameter and depth of the thread. the pitch of the thread is marked off by arcs, as , , etc., or by laying a rule directly on the centre line and marking with a lead pencil. to obtain the slant of the thread, lines and are drawn, and from these line , touching and where they meet lines and ; the threads may then be drawn in from the arcs as , , etc. the side of the thread will show at the top and the bottom as at a b, because of the coarse pitch and the thread on the other or unseen side of the bolt slants, as denoted by the lines , ; and hence to draw the sides a b, the triangle must be set from one thread to the next on the opposite side of the bolt, as denoted by the dotted lines and . [illustration: fig. .] if the curves of the thread are to be drawn in, they may be obtained as in figure , which is substantially the same as described for a v thread. the curves _f_, representing the sides of the thread, terminate at the centre line _g_, and the curves _e_ are equidistant with the curves _c_ from the vertical lines _d_. as the curves _f_ above the line are the same as _f_ below the line, the template for _f_ need not be made to extend the whole distance across, but one-half only; as is shown by the dotted curve _g_, in the construction for finding the curve for square-threaded nuts in figure . [illustration: fig. .] [illustration: fig. .] a specimen of the form of template for drawing these curves is shown in figure ; _g_ _g_, is the centre line parallel to the edges r, s; lines _m_, _n_, represent the diameter of the thread at the top, and _o_, _p_, that at the bottom or root; edge _a_ is formed to the points (found by the constructions in the figures as already explained) for the tops of the thread, and edge _f_ is so formed for the curve at the thread bottoms. the edge, as s or r, is laid against the square-blade to steady it while drawing in the curves. it may be noted, however, that since the curve is the same below the centre line as it is above, the template may be made to serve for one-half the thread diameter, as at _f_, where it is made from _o_ to _g_, only being turned upside down to draw the other half of the curve; the notches cut out at _x_, _x_, are merely to let the pencil-lines in the drawing show plainly when setting the template. when the thread of a nut is shown in section, it slants in the opposite direction to that which appears on the bolt-thread, because it shows the thread that fits to the opposite side of the bolt, which, therefore, slants in the opposite direction, as shown by the lines and in figure . in a top or end view of a nut the thread depth is usually shown by a simple circle, as in figure . [illustration: fig. .] to draw a spiral spring, draw the centre line a, and lines b, c, figure , distant apart the diameter the spring is to be less the diameter of the wire of which it is to be made. on the centre line a mark two lines _a b_, _c d_, representing the pitch of the spring. divide the distance between _a_ and _b_ into four equal divisions, as by lines , , , letting line meet line b. line _e_ meeting the centre line at line _a_, and the line b at its intersection with line , is the angle of the coil on one side of the spring; hence it may be marked in at all the locations, as at _e f_, etc. these lines give at their intersections with the lines c and b the centres for the half circles _g_, which being drawn, the sides _h_, _i_, _j_, _k_, etc., of the spring, may all be marked in. by the lines _m_, _n_, _o_, _p_, the other sides of the spring may be marked in. [illustration: fig. .] the end of the spring is usually marked straight across, as at l. if it is required to draw the coils curved instead of straight across, a template must be made, the curve being obtained as already described for threads. it may be pointed out, however, that to obtain as accurate a division as possible of the lines that divide the pitch, the pitch may be divided upon a diagonal line, as f, figure , which will greatly facilitate the operation. [illustration: fig. .] before going into projections it may be as well to give some examples for practice. [illustration: fig. . (page .)] chapter ix. _examples for practice._ figure represents a simple example for practice, which the student may draw the size of the engraving, or he may draw it twice the size. it is a locomotive spring, composed of leaves or plates, held together by a central band. [illustration: fig. .] figure is an example of a stuffing box and gland, supposed to stand vertical, hence the gland has an oil cup or receptacle. in figure are working drawings of a coupling rod, with the dimensions and directions marked in. it may be remarked, however, that the drawings of a workshop are, where large quantities of the same kind of work is done, varied in character to suit some special departments--that is to say, special extra drawings are made for these departments. in figures and is a drawing of a connecting rod drawn, put together as it would be for the lathe, vise or erecting shop. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] to the two views shown there would be necessary detail sketches of the set screws, gibbs, and keys, all the rest being shown; the necessary dimensions being, of course, marked on the general drawing and on the details. in so simple a thing as a connecting rod, however, there would be no question as to how the parts go together; hence detail drawings of each separate piece would answer for the lathe or vise bands. but in many cases this would not be the case, and the drawing would require to show the parts put together, and be accompanied with such detail sketches as might be necessary to show parts that could not be clearly defined in the general views. the blacksmith, for example, is only concerned with the making of the separate pieces, and has no concern as to how the parts go together. furthermore, there are parts and dimensions in the general drawing with which the blacksmith has nothing to do. thus the location and dimensions of the keyways, the dimensions of the brasses, and the location of the bolt holes, are matters that have no reference to the blacksmith's work, because the keyways, bolt holes, and set-screw holes would be cut out of the solid in the machine shop. it is customary, therefore, to send to the blacksmith shop drawings containing separate views of each piece drawn to the shape it is to be forged; and drawn full size, or else on a scale sufficiently large to make each part show clearly without close inspection, marking thereon the full sizes, and stating beneath the number of pieces of each detail. (as in figure , which represents the iron work of the connecting rod in figure ). in some cases the finished sizes are marked, and it is left to the blacksmith's judgment how much to leave for the finishing. this is undesirable, because either the blacksmith is left to judge what parts are to be finished, or else there must be on the drawing instructions on this point, or else signs or symbols that are understood to convey the information. it is better, therefore, to make for the blacksmith a special sketch, and mark thereon the full-forged sizes, stating on the drawing that such is the case. [illustration: fig. ] as to the material of which the pieces are to be made, the greater part of blacksmith work is made of wrought iron, and it is, therefore, unnecessary to write "wrought iron" beneath each piece. when the pieces are to be of steel, however, it should be marked on the drawing and beneath the piece. in special cases, as where the greater part of the work of the shop is of steel, the rule may, of course, be reversed, and the parts made of iron may be the ones marked, whereas when parts are sometimes of iron, and at others of steel, each piece should be marked. as a general rule the blacksmith knows, from the custom of the shop or the nature of the work, what the quality or kind of iron is to be, and it is, therefore, only in exceptional cases that they need to be mentioned on the drawing. thus in a carriage manufactory, norway or swede iron will be found, as well as the better grades of refined iron, but the blacksmith will know what iron to use, for certain parts, or the shop may be so regulated that the selection of the iron is not left to him. in marking the number of pieces required, it is better to use the word "thus" than the words "of this," or "off this," because it is shorter and more correct, for the forging is not taken off the drawing, nor is it of the same; the drawing gives the shape and the size, and the word "thus" conveys that idea better than "of," "off," or "like this." in shops where there are many of the same pieces forged, the blacksmith is furnished with sheet-iron templates that he can lay directly upon the forging and test its dimensions at once, which is an excellent plan in large work. such templates are, of course, made from the drawings, and it becomes a question as to whether their dimensions should be the forged or the finished ones. if they are the forged, they may cause trouble, because a forging may have a scant place that it is difficult for the blacksmith to bring up to the size of the template, and he is in doubt whether there is enough metal in the scant place to allow the job to clean up. it is better, therefore, to make them to finished sizes, so that he can see at once if the work will clean up, notwithstanding the scant place. this will lead to no errors in large work, because such work is marked out by lines, and the scant part will therefore be discovered by the machinist, who will line out the piece accordingly. figure is a drawing of a locomotive frame, which the student may as well draw three or four times as large as the engraving, which brings us to the subject of enlarging or reducing scales. reducing scales. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] it is sometimes necessary to reduce a drawing to a smaller scale, or to find a minute fraction of a given dimension, such fraction not being marked on the lineal measuring rules at hand. figure represents a scale for finding minute fractions. draw seven lines parallel to each other, and equidistant draw vertical lines dividing the scale into half-inches, as at _a_, _b_, _c_, etc. divide the first space _e d_ into equal halves, draw diagonal lines, and number them as in the figure. the distance of point , which is at the intersection of diagonal with the second horizontal line, will be / inch from vertical line _e_. point will be / inch from line _e_, and so on. for tenths of inches there would require to be but six horizontal lines, the diagonals being drawn as before. a similar scale is shown in figure . draw the lines a b, b d, d c, c a, enclosing a square inch. divide each of these lines into ten equal divisions, and number and letter them as shown. draw also the diagonal lines a , _a_ , b , and so on; then the distances from the line a c to the points of intersection of the diagonals with the horizontal lines represent hundredths of an inch. suppose, for example, we trace one diagonal line in its path across the figure, taking that which starts from a and ends at on the top horizontal line; then where the diagonal intersects _horizontal_ line , is / from the line b d, and / from the line a c, while where it intersects _horizontal_ line , is / from line b d, and / from line a c, and so on. if we require to set the compasses to / inch, we set them to the radius of _n_, and the figure on line b d, because from that to the vertical line _d_ is / or / inch, and from that vertical line to the diagonal at _n_ is seven divisions from the line c d of the figure. in making a drawing to scale, however, it is an excellent plan to draw a line and divide it off to suit the required scale. suppose, for example, that the given scale is one-quarter size, or three inches per foot; then a line three inches long may be divided into twelve equal divisions, representing twelve inches, and these may be subdivided into half or quarter inches and so on. it is recommended to the beginner, however, to spend all his time making simple drawings, without making them to scale, in order to become so familiar with the use of the instruments as to feel at home with them, avoiding the complication of early studies that would accompany drawing to scale. chapter x. _projections._ in projecting, the lines in one view are used to mark those in other views, and to find their shapes or curvature as they will appear in other views. thus, in figure _a_ we have a spiral, wound around a cylinder whose end is cut off at an angle. the pitch of the spiral is the distance a b, and we may delineate the curve of the spiral looking at the cylinder from two positions (one at a right-angle to the other, as is shown in the figure), by means of a circle having a circumference equal to that of the cylinder. the circumference of this circle we divide into any number of equidistant divisions, as from to . the pitch a b of the spiral or thread is then divided off also into equidistant divisions, as marked on the left hand of the figure; vertical lines are then drawn from the points of division on the circle to the points correspondingly numbered on the lines dividing the pitch; and where line on the circle intersects line on the pitch is one point in the curve. similarly, where point on the circle intersects line on the pitch is another point in the curve, and so on for the whole divisions on the circle and on the pitch. in this view, however, the path of the spiral from line to line lies on the other side of the cylinder, and is marked in dotted lines, because it is hidden by the cylinder. in the right-hand view, however, a different portion of the spiral or thread is hidden, namely from lines to inclusive, being an equal proportion to that hidden in the left-hand view. [illustration: fig. _a_.] the top of the cylinder is shown in the left-hand view to be cut off at an angle to the axis, and will therefore appear elliptical; in the right-hand view, to delineate this oval, the same vertical lines from the circle may be carried up as shown on the right hand, and horizontal lines may be drawn from the inclined face in one view across the end of the other view, as at p; the divisions on the circle may be carried up on the right-hand view by means of straight lines, as q, and arcs of circle, as at r, and vertical lines drawn from these arcs, as line s, and where these vertical lines s intersect the horizontal lines as p, are points in the ellipse. let it be required to draw a cylindrical body joining another at a right-angle; as for example, a tee, such as in figure , and the outline can all be shown in one view, but it is required to find the line of junction of one piece, a, with the other, b; that is, find or mark the lines of junction c. now when the diameters of a and b are equal, the line of junction c is a straight line, but it becomes a curved one when the diameter of a is less than that of b, or _vice versa_; hence it may be as well to project it in both cases. for this purpose the three views are necessary. one-quarter of the circle of b, in the end view, is divided off into any number of equal divisions; thus we have chosen the divisions marked _a_, _b_, _c_, _d_, _e_, etc.; a quarter of the top view is similarly divided off, as at _f_, _g_, _h_, _i_, _j_; from these points of division lines are projected on to the side view, as shown by the dotted lines _k_, _l_, _m_, _n_, _o_, _p_, etc., and where these lines meet, as denoted by the dots, is in each case a point in the line of junction of the two cylinders a, b. [illustration: fig. .] [illustration: fig. .] figure represents a tee, in which b is less in diameter than a; hence the two join in a curve, which is found in a similar manner, as is shown in figure . suppose that the end and top views are drawn, and that the side view is drawn in outline, but that the curve of junction or intersection is to be found. now it is evident that since the centre line passes through the side and end views, that the face _a_, in the end view, will be even with the face _a'_ in the side view, both being the same face, and as the full length of the side of b in the end view is marked by line _b_, therefore line _c_ projected down from _b_ will at its junction with line _b'_, which corresponds to line _b_, give the extreme depth to which _b'_ extends into the body a, and therefore, the apex of the curve of intersection of b with a. to obtain other points, we divide one-quarter of the circumference of the circle b in the top view into four equal divisions, as by lines _d_, _e_, _f_, and from the points of division we draw lines _j_, _i_, _g_, to the centre line marked , these lines being thickened in the cut for clearness of illustration. the compasses are then set to the length of thickened line _g_, and from point _h_, in the end view, as a centre, the arc _g'_ is marked. with the compasses set to the length of thickened line _i_, and from _h_ as a centre, arc _i'_ is marked, and with the length of thickened line _j_ as a radius and from _h_ as a centre arc _j'_ is marked; from these arcs lines _k_, _l_, _m_ are drawn, and from the intersection of _k_, _l_, _m_, with the circle of a, lines _n_, _o_, _p_ are let fall. from the lines of division, _d_, _e_, _f_, the lines _q_, _r_, _s_ are drawn, and where lines _n_, _o_, _p_ join lines _q_, _r_, _s_, are points in the curve, as shown by the dots, and by drawing a line to intersect these dots the curve is obtained on one-half of b. since the axis of b is in the same plane as that of a, the lower half of the curve is of the same curvature as the upper, as is shown by the dotted curve. [illustration: fig. .] in figure the axis of piece b is not in the same plane as that of d, but to one side of it to the distance between the centre lines c, d, which is most clearly seen in the top view. in this case the process is the same except in the following points: in the side view the line _w_, corresponding to the line _w_ in the end view, passes within the line _x_ before the curve of intersection begins, and in transferring the lengths of the full lines _b_, _c_, _d_, _e_, _f_ to the end view, and marking the arcs _b'_, _c'_, _d'_, _e'_, _f'_, they are marked from the point _w_ (the point where the centre line of b intersects the outline of a), instead of from the point _x_. in all other respects the construction is the same as that in figure . [illustration: fig. .] in these examples the axis of b stands at a right-angle to that of a. but in figure is shown the construction where the axis of b is not at a right-angle to a. in this case there is projected from b, in the side view, an end view of b as at b', and across this end at a right-angle to the centre line of b is marked a centre line c c of b', which is divided as before by lines _d_, _e_, _f_, _g_, _h_, their respective lengths being transferred from w as a centre, and marked by the arcs _d'_, _e'_, _f'_, which are marked on a vertical line and carried by horizontal lines, to the arc of a as at _i_, _j_, _k_. from these points, _i_, _j_, _k_, the perpendicular lines _l_, _m_, _n_, _o_, are dropped, and where these lines meet lines _p_, _q_, _r_, _s_, _t_, are points in the curve of intersection of b with a. it will be observed that each of the lines _m_, _n_, _o_, serves for two of the points in the curve; thus, _m_ meets _q_ and _s_, while _n_ meets _p_ and _t_, and _o_ meets the outline on each side of b, in the side view, and as _i_, _j_, _k_ are obtained from _d_ and _e_, the lines _g_ and _h_ might have been omitted, being inserted merely for the sake of illustration. in figure is an example in which a cylinder intersects a cone, the axes being parallel. to obtain the curve of intersection in this case, the side view is divided by any convenient number of lines, as _a_, _b_, _c_, etc., drawn at a right-angle to its axis a a, and from one end of these lines are let fall the perpendiculars _f_, _g_, _h_, _i_, _j_; from the ends of these (where they meet the centre line of a in the top view), half-circles _k_, _l_, _m_, _n_, _o_, are drawn to meet the circle of b in the top view, and from their points of intersection with b, lines _p_, _q_, _r_, _s_, _t_, are drawn, and where these meet lines _a_, _b_, _c_, _d_ and _e_, which is at _u_, _v_, _w_, _x_, _y_, are points in the curve. [illustration: fig. .] [illustration: fig. .] it will be observed, on referring again to figure , that the branch or cylinder b appears to be of elliptical section on its end face, which occurs because it is seen at an angle to its end surface; now the method of finding the ellipse for any given degree of angle is as in figure , in which b represents a cylindrical body whose top face would, if viewed from point i, appear as a straight line, while if viewed from point j it would appear in outline a circle. now if viewed from point e its apparent dimension in one direction will obviously be defined by the lines s, z. so that if on a line g g at a right angle to the line of vision e, we mark points touching lines s, z, we get points and , representing the apparent dimension in that direction which is the width of the ellipse. the length of the ellipse will obviously be the full diameter of the cylinder b; hence from e as a centre we mark points and , and of the remaining points we will speak presently. suppose now the angle the top face of b is viewed from is denoted by the line l, and lines s', z, parallel to l, will be the width for the ellipse whose length is marked by dots, equidistant on each side of centre line g' g', which equal in their widths one from the other the full diameter of b. in this construction the ellipse will be drawn away from the cylinder b, and the ellipse, after being found, would have to be transferred to the end of b. but since centre line g g is obviously at the same angle to a a that a a is to g g, we may start from the centre line of the body whose elliptical appearance is to be drawn, and draw a centre line a a at the same angle to g g as the end of b is supposed to be viewed from. this is done in figure _a_, in which the end face of b is to be drawn viewed from a point on the line g g, but at an angle of degrees; hence line a a is drawn at an angle of degrees to centre line g g, and centre line e is drawn from the centre of the end of b at a right angle to g g, and from where it cuts a a, as at f, a side view of b is drawn, or a single line of a length equal to the diameter of b may be drawn at a right angle to a a and equidistant on each side of f. a line, d d, at a right angle to a a, and at any convenient distance above f, is then drawn, and from its intersection with a a as a centre, a circle c equal to the diameter of b is drawn; one-half of the circumference of c is divided off into any number of equal divisions as by arcs _a_, _b_, _c_, _d_, _e_, _f_. from these points of division, lines _g_, _h_, _i_, _j_, _k_, _l_ are drawn, and also lines _m_, _n_, _o_, _p_, _q_, _r_. from the intersection of these last lines with the face in the side view, lines _s_, _t_, _u_, _t_, _w_, _x_, _y_, _z_ are drawn, and from point f line e is drawn. now it is clear that the width of the end face of the cylinder will appear the same from any point of view it may be looked at, hence the sides h h are made to equal the diameter of the cylinder b and marked up to centre line e. [illustration: fig. _a_.] [illustration: fig. .] it is obvious also that the lines _s_, _z_, drawn from the extremes of the face to be projected will define the width of the ellipse, hence we have four of the points (marked respectively , , , ) in the ellipse. to obtain the remaining points, lines _t_, _u_, _v_, _w_, _x_, _y_ (which start from the point on the face f where the lines _m_, _n_, _o_, _p_, _q_, _r_, respectively meet it) are drawn across the face of b as shown. the compasses are then set to the radius _g_; that is, from centre line d to division _a_ on the circle, and this radius is transferred to the face to be projected the compass-point being rested at the intersection of centre line g and line _t_, and two arcs as and drawn, giving two more points in the curve of the ellipse. the compasses are then set to the length of line _h_ (that is, from centre line d to point of division _b_), and this distance is transferred, setting the compasses on centre line g where it is intersected by line _u_, and arcs , are marked, giving two more points in the ellipse. in like manner points and are obtained from the length of line _i_, and from that of _j_; points and from the length of _k_, and and from _l_, and the ellipse may be drawn in from these points. it may be pointed out, however, that since points and are the same distance from g that points and are, and since points and are the same distance from g that points and are, while points and are the same distance from g that and are, the lines, _j_, _k_, _l_ are unnecessary, since _l_ and _g_ are of equal length, as are also _h_ and _k_ and _i_ and _j_. in figure the cylinders are line shaded to make them show plainer to the eye, and but three lines (_a_, _b_, _c_) are used to get the radius wherefrom to mark the arcs where the points in the ellipse shall fall; thus, radius _a_ gives points , , and ; radius _b_ gives points , , and , and radius _c_ gives , , and , the extreme diameter being obtained from lines s, z, and h, h. chapter xi. _drawing gear wheels._ the names given to the various lines of a tooth on a gear-wheel are as follows: in figure , a is the face and b the flank of a tooth, while c is the point, and d the root of the tooth; e is the height or depth, and f the breadth. p p is the pitch circle, and the space between the two teeth, as h, is termed a space. [illustration: fig. .] [illustration: fig. .] it is obvious that the points of the teeth and the bottoms of the spaces, as well as the pitch circle, are concentric to the axis of the wheel bore. and to pencil in the teeth these circles must be fully drawn, as in figure , in which p p is the pitch circle. this circle is divided into as many equal divisions as the wheel is to have teeth, these divisions being denoted by the radial lines, a, b, c, etc. where these divisions intersect the pitch circle are the centres from which all the teeth curves may be drawn. the compasses are set to a radius equal to the pitch, less one-half the thickness of the tooth, and from a centre, as r, two face curves, as f g, may be marked; from the next centre, as at s, the curves d e may be marked, and so on for all the faces; that is, the tooth curves lying between the outer circle x and the pitch circle p. for the flank curves, that is, the curve from p to y, the compasses are set to a radius equal to the pitch; and from the sides of the teeth the flank curves are drawn. thus from j, as a centre flank, k is drawn; from v, as a centre flank, h is drawn, and so on. the proportions of the teeth for cast gears generally accepted in this country are those given by professor willis, as average practice, and are as follows: depth to pitch line, / of the pitch. working depth, / " " whole depth, / " " thickness of tooth, / " " breadth of space, / " " instead, however, of calculating the dimensions these proportions give for any particular pitch, a diagram or scale may be made from which they may be taken for any pitch by a direct application of the compasses. a scale of this kind is given in figure , in which the line a b is divided into inches and parts to represent the pitches; its total length representing the coarsest pitch within the capacity of the scale; and, the line b c (at a right-angle to a b) the whole depth of the tooth for the coarsest pitch, being / of the length of a b. [illustration: fig. .] the other diagonal lines are for the proportion of the dimensions marked on the figure. thus the depth of face, or distance from the pitch line to the extremity or tooth point for a inch pitch, would be measured along the line b c, from the vertical line b to the first diagonal. the thickness of the tooth would be for a inch pitch along line b c from b to the second diagonal, and so on. for a inch pitch the measurement would be taken along the horizontal line, starting from the on the line a b, and so on. on the left of the diagram or scale is marked the lbs. strain each pitch will safely transmit per inch width of wheel face, according to professor marks. [illustration: fig. .] the application of the scale as follows: the pitch circles p p and p' p', figure , for the respective wheels, are drawn, and the height of the teeth is obtained from the scale and marked beyond the pitch circles, when circles q and q' may be drawn. similarly, the depths of the teeth within the pitch circles are obtained from the scale or diagram and marked within the respective pitch circles, and circles r and r' are marked in. the pitch circles are divided off into as many points of equal division, as at _a_, _b_, _c_, _d_, _e_, etc., as the respective wheels are to have teeth, and the thickness of tooth having been obtained from the scale, this thickness is marked from the points of division on the pitch circles, as at _f_ in the figure, and the tooth curves may then be drawn in. it may be observed, however, that the tooth thicknesses will not be strictly correct, because the scale gives the same chord pitch for the teeth on both wheels which will give different arc pitches to the teeth on the two wheels; whereas, it is the arc pitches, and not the chord pitches, that should be correct. this error obviously increases as there is a greater amount of difference between the two wheels. the curves given to the teeth in figure are not the proper ones to transmit uniform motion, but are curves merely used by draughtsmen to save the trouble of finding the true curves, which if it be required, may be drawn with a very near approach to accuracy, as follows, which is a construction given by rankine: draw the rolling circle d, figure , and draw a d, the line of centres. from the point of contact at c, mark on d, a point distant from c one-half the amount of the pitch, as at p, and draw the line p c of indefinite length beyond c. draw the line p e passing through the line of centres at e, which is equidistant between c and a. then increase the length of line p f to the right of c by an amount equal to the radius a c, and then diminish it to an amount equal to the radius e d, thus obtaining the point f and the latter will be the location of centre for compasses to strike the face curve. [illustration: fig. .] [illustration: fig. .] another method of finding the face curve, with compasses, is as follows: in figure let p p represent the pitch circle of the wheel to be marked, and b c the path of the centre of the generating or describing circle as it rolls outside of p p. let the point b represent the centre of the generating circle when it is in contact with the pitch circle at a. then from b mark off, on b c, any number of equidistant points, as d, e, f, g, h, and from a mark on the pitch circle, with the same radius, an equal number of points of division, as , , , , . with the compasses set to the radius of the generating circle, that is, a b, from b, as a centre, mark the arc i, from d, the arc j, from e, the arc k, from f, and so on, marking as many arcs as there are points of division on b c. with the compasses set to the radius of divisions , , etc., step off on arc m the five divisions, n, o, s, t, v, and at v will be a point on the epicycloidal curve. from point of division , step off on l four points of division, as _a_, _b_, _c_, _d_; and _d_ will be another point on the epicycloidal curve. from point , set off three divisions, and so on, and through the points so obtained draw by hand, or with a scroll, the curve. [illustration: fig. .] hypocycloids for the flanks of the teeth maybe traced in a similar manner. thus in figure , p p is the pitch circle, and b c the line of motion of the centre of the generating circle to be rolled within p p. from to are points of equal division on the pitch circle, and d to i are arc locations for the centre of the generating circle. starting from a, which represents the location for the centre of the generating circle, the point of contact between the generating and base circles will be at b. then from to are points of equal division on the pitch circle, and from d to i are the corresponding locations for the centres of the generating circle. from these centres the arcs j, k, l, m, n, o, are struck. the six divisions on o, from _a_ to _f_, give at _f_ a point in the curve. five divisions on n, four on m, and so on, give, respectively, points in the curve. there is this, however, to be noted concerning the construction of the last two figures. since the circle described by the centre of the generating circle is of a different arc or curve to that of the pitch circle, the length of an arc having an equal radius on each will be different. the amount is so small as to be practically correct. the direction of the error is to give to the curves a less curvature, as though they had been produced by a generating circle of larger diameter. suppose, for example, that the difference between the arc _a_, _b_, and its chord is . , and that the difference between the arc , , and its chord is . , then the error in one step is . , and, as the point _f_ is formed in five steps, it will contain this error multiplied five times. point _d_ would contain it multiplied three times, because it has three steps, and so on. the error will increase in proportion as the diameter of the generating is less than that of the pitch circle, and though in large wheels, working with large wheels, so that the difference between the radius of the generating circle and that of the smallest wheel is not excessive, it is so small as to be practically inappreciable, yet in small wheels, working with large ones, it may form a sensible error. [illustration: fig. .] for showing the dimensions through the arms and hub, a sectional view of a section of the wheel may be given, as in figure , which represents a section of a wheel, and a pinion, and on these two views all the necessary dimensions may be marked. [illustration: fig. _a_. (page .)] if it is desired to draw an edge view of a wheel (which the student will find excellent practice), the lines for the teeth may be projected from the teeth in the side view, as in figure _a_. thus tooth e is projected by drawing lines from the corners a, b, c, in the side view across the face in the edge view, as at a, b, c in the latter view, and similar lines may be obtained in the same way for all the teeth. when the teeth of wheels are to be cut to form in a gear-cutting machine, the thickness of the teeth is nearly equal to the thickness of the spaces, there being just sufficient difference to prevent the teeth of one wheel from becoming locked in the spaces of the other; but when the teeth are to be cast upon the wheel, the tooth thickness is made less than the width of the space to an amount that is usually a certain proportion of the pitch, and is termed the side clearance. in all wheels, whether with cut or cast teeth, there is given a certain amount of top and bottom clearance; that is to say, the points of the teeth of one wheel do not reach to the bottom of the spaces in the other. thus in the pratt and whitney system the top and bottom clearance is one-eighth of the pitch, while in the brown and sharpe system for involute teeth the clearance is equal to one-tenth the thickness of the tooth. in drawing bevil gear wheels, the pitch line of each tooth on each wheel, and the surfaces of the points, as well as those at the bottom of the spaces, must all point to a centre, as e in figure , which centre is where the axes of the shafts would meet. it is unnecessary to mark in the correct curves for the teeth, for reasons already stated, with reference to the curves for a spur wheel. but if it is required to do so, the construction to find the curves is as shown in figure , in which let a a represent the axis of one shaft, and b that of the other of the pair of bevil wheels that are to work together, their axes meeting at w; draw the line e at a right angle to a a, and representing the pitch circle diameter of one wheel, and draw f at a right angle to b, and representing the pitch circle of the other wheel; draw the line g g, passing through the point w and the point t, where the pitch circles or lines e f meet, and g g will be the line of contact of the tooth of one wheel upon the tooth of the other wheel; or in other words, the pitch line of the tooth. [illustration: fig. .] [illustration: fig. .] draw lines, as h and i, representing the tooth breadth. from w, as a centre, draw on each side of g g dotted lines, as p, representing the height of the tooth above and below the pitch line g g. at a right angle to g g draw the line j k; and from where this line meets b, as at q, mark the arc _a_, which will represent the pitch circle for the large diameter of the pinion d. [the smallest wheel of a pair of gears is termed the pinion.] draw the arc _b_ for the height, and circle _c_ for the depth of the teeth, thus defining the height of the tooth at that end. similarly from p, as a centre mark (for the large diameter of wheel c,) arcs _g_, _h_, and _i_, arc _g_ representing the pitch circle, _i_ the height, and _h_ the depth of the tooth. on these arcs draw the proper tooth curves in the same manner as for spur wheels; that is, obtain the curves by the construction shown in figures , or by those in figures and . to obtain the arcs for the other end of the tooth, draw line m m parallel to line j k; set the compasses to the radius r l, and from p, as a centre, draw the pitch circle _k_. for the depth of the tooth draw the dotted line _p_, meeting the circle _h_ and the point w. a similar line, from _i_ to w, will give the height of the tooth at its inner end. then the tooth curves may be drawn on these three arcs, _k_, _l_, _m_, in the same as if they were for a spur wheel. similarly for the pitch circle of the inner and small end of the pinion teeth, set the compasses to radius s l, and from q as a centre mark the pitch circle _d_. outside of _d_ mark _e_ for the height above pitch lines of the tooth, and inside of _d_ mark the arc _f_ for the depth below pitch line of the tooth at that end. the distance between the dotted lines as _p_, represents the full height of the tooth; hence _h_ meets _p_, which is the root of the tooth on the large wheel. to give clearance and prevent the tops of the teeth on one wheel from bearing against the bottoms of the spaces in the other wheel, the point of the pinion teeth is marked below; thus arc _b_ does not meet _h_ or _p_, but is short to the amount of clearance. having obtained the arcs _d_, _e_, _f_, the curves may be marked thereon as for a spur wheel. a tooth thus marked is shown at _x_, and from its curves between _b_ and _c_, a template may be made for the large diameter or outer end of the pinion teeth. similarly for the wheel c the outer end curves are marked on the arcs _g_, _h_, _i_, and those for the other end of the tooth are marked between the arcs _l_, _m_. [illustration: fig. . (page .)] [illustration: fig. .] figure represents a drawing of one-half of a bevil gear, and an edge view projected from the same. the point e corresponds to point e in figure , or w in . the line f shows that the top surface of the teeth points to e. line g shows that the pitch line of each tooth points to e, and lines h show that the bottom of the surface of a space also points to e. line shows that the sides of each tooth point to e. and it follows that the outer end of a tooth is both higher or deeper and also thicker than its inner end; thus j is thicker and deeper than end k of the tooth. lines f g, representing the top and bottom of a tooth in figure , obviously correspond to dotted lines _p_ in figure . the outer and inner ends of the teeth in the edge view are projected from the outer and inner ends in the face view, as is shown by the dotted lines carried from tooth l in the face view, to tooth l in the edge view, and it is obvious from what has been said that in drawing the lines for the tooth in the edge view they will point to the centre e. [illustration: fig. .] to save work in drawing bevil gear wheels, they are sometimes drawn in section or in outline only; thus in figure is shown a pair of bevil wheels shown in section, and in figure is a drawing of a part of an ames lathe feed motion. b c d and e are spur gears, while g h and i are bevil gears, the cone surface on which the teeth lie being left blank, save at the edges where a tooth is in each case drawn in. wheel d is shown in section so as to show the means by which it may be moved out of gear with c and e. small bevil gears may also be represented by simple line shading; thus in figure the two bodies a and c would readily be understood to be a bevil gear and pinion. similarly small spur wheels may be represented by simple circles in a side view and by line shading in an edge view; thus it would answer every practical purpose if such small wheels as in figures and at d, f, g, k, p, h, i and j, were drawn as shown. the pitch circles, however, are usually drawn in red ink to distinguish them. [illustration: fig. . (page .)] [illustration: fig. .] [illustration: fig. .] in figure is an example in which part of the gear is shown with teeth in, and the remainder is illustrated by circles. in figure is a drawing of part of the feed motions of a niles tool works horizontal boring mill, figure being an end view of the same, _f_ is a friction disk, and _g_ a friction pinion, _g'_ is a rack, f is a feed-screw, _p_ is a bevil pinion, and _q_ a bevil wheel; _i_, _m_, _o_, are gear wheels, and _j_ a worm operating a worm-pinion and the gears shown. figure represents three bevil gears, the upper of which is line shaded, forming an excellent example for the student to copy. [illustration: fig. .] the construction of oval gearing is shown in figures , , , , and . the pitch-circle is drawn by the construction for drawing an ellipse that was given with reference to figure , but as that construction is by means of arcs of circles, and therefore not strictly correct, professor mccord, in an article on elliptical gearing, says, concerning it and the construction of oval gearing generally, as follows: [illustration: fig. . (page .)] [illustration: fig. .] [illustration: fig. .] "but these circular arcs may be rectified and subdivided with great facility and accuracy by a very simple process, which we take from prof. rankine's "machinery and mill work," and is illustrated in figure . let o b be tangent at o to the arc o d, of which c is the centre. draw the chord d o, bisect it in e, and produce it to a, making o a=o e; with centre a and radius a d describe an arc cutting the tangent in b; then o b will be very nearly equal in length to the arc o d, which, however, should not exceed about degrees; if it be degrees, the error is theoretically about / of the length of the arc, o b being so much too short; but this error varies with the fourth power of the angle subtended by the arc, so that for degrees it is reduced to / of that amount, that is, to / . conversely, let o b be a tangent of given length; make o f= / o b; then with centre f and radius f b describe an arc cutting the circle o d g (tangent to o b at o) in the point d; then o d will be approximately equal to o b, the error being the same as in the other construction and following the same law. [illustration: fig. .] the extreme simplicity of these two constructions and the facility with which they may be made with ordinary drawing instruments make them exceedingly convenient, and they should be more widely known than they are. their application to the present problem is shown in figure , which represents a quadrant of an ellipse, the approximate arcs c d, e, e f, f a having been determined by trial and error. in order to space this off, for the positions of the teeth, a tangent is drawn at d, upon which is constructed the rectification of d c, which is d g, and also that of d e in the opposite direction, that is, d h, by the process just explained. then, drawing the tangent at f, we set off in the same manner f i = f e, and f k = f a, and then measuring h l = i k, we have finally g l, equal to the whole quadrant of the ellipse. [illustration: fig. .] let it now be required to lay out twenty-four teeth upon this ellipse; that is, six in each quadrant; and for symmetry's sake we will suppose that the centre of one tooth is to be at a, and that of another at c, figure . we, therefore, divide l g into six equal parts at the points , , , etc., which will be the centres of the teeth upon the rectified ellipse. it is practically necessary to make the spaces a little greater than the teeth; but if the greatest attainable exactness in the operation of the wheels is aimed at, it is important to observe that backlash, in elliptical gearing, has an effect quite different from that resulting in the case of circular wheels. when the pitch-curves are circles, they are always in contact; and we may, if we choose, make the tooth only half the breadth of the space, so long as its outline is correct. when the motion of the driver is reversed, the follower will stand still until the backlash is taken up, when the motion will go on with a perfectly constant velocity ratio as before. but in the case of two elliptical wheels, if the follower stand still while the driver moves, which must happen when the motion is reversed if backlash exists, the pitch-curves are thrown out of contact, and, although the continuity of the motion will not be interrupted, the velocity ratio will be affected. if the motion is never to be reversed, the perfect law of the velocity ratio due to the elliptical pitch-curve may be preserved by reducing the thickness of the tooth, not equally on each side, as is done in circular wheels, but wholly on the side not in action. but if the machine must be capable of acting indifferently in both directions, the reduction must be made on both sides of the tooth: evidently the action will be slightly impaired, for which reason the backlash should be reduced to a minimum. precisely what _is_ the minimum is not so easy to say, as it evidently depends much upon the excellence of the tools and the skill of the workman. in many treatises on constructive mechanism it is variously stated that the backlash should be from one-fifteenth to one-eleventh of the pitch, which would seem to be an ample allowance in reasonably good castings not intended to be finished, and quite excessive if the teeth are to be cut; nor is it very obvious that its amount should depend upon the pitch any more than upon the precession of the equinoxes. on paper, at any rate, we may reduce it to zero, and make the teeth and spaces equal in breadth, as shown in the figure, the teeth being indicated by the double lines. those upon the portion l h are then laid off upon k i, after which these divisions are transferred to the ellipse by the second of prof. rankine's constructions, and we are then ready to draw the teeth. the outlines of these, as of any other teeth upon pitch-curves which roll together in the same plane, depend upon the general law that they must be such as can be marked out upon the planes of the curves, as they roll by a tracing-point, which is rigidly connected with and carried by a third line, moving in rolling contact with both the pitch-curves. and since under that condition the motion of this third line, relatively to each of the others, is the same as though it rolled along each of them separately while they remained fixed, the process of constructing the generated curves becomes comparatively simple. for the describing line we naturally select a circle, which, in order to fulfil the condition, must be small enough to roll within the pitch ellipse; its diameter is determined by the consideration that if it be equal to a p, the radius of the arc a f, the flanks of the teeth in that region will be radial. we have, therefore, chosen a circle whose diameter, a b, is three-fourths of a p, as shown, so that the teeth, even at the ends of the wheels, will be broader at the base than on the pitch line. this circle ought strictly to roll upon the true elliptical curve; and assuming, as usual, the tracing-point upon the circumference, the generated curves would vary slightly from true epicycloids, and no two of those used in the same quadrant of the ellipse would be exactly alike. were it possible to divide the ellipse accurately, there would be no difficulty in laying out these curves; but having substituted the circular arcs, we must now roll the generating circle upon these as bases, thus forming true epicycloidal teeth, of which those lying upon the same approximating arc will be exactly alike. should the junction of two of these arcs fall within the breadth of a tooth, as at d, evidently both the face and the flank on one side of that tooth will be different from those on the other side; should the junction coincide with the edge of a tooth, which is very nearly the case at f, then the face on that side will be the epicycloid belonging to one of the arcs, its flank a hypocycloid belonging to the other; and it is possible that either the face or the flank on one side should be generated by the rolling of the describing circle partly on one arc, partly on the one adjacent, which, upon a large scale, and where the best results are aimed at, may make a sensible change in the form of the curve. the convenience of the constructions given in figure is nowhere more apparent than in the drawing of the epicycloids, when, as in the case in hand the base and generating circles may be of incommensurable diameters; for which reason we have, in figure , shown its application in connection with the most rapid and accurate mode yet known of describing those curves. let c be the centre of the base circle; b, that of the rolling one; a, the point of contact. divide the semi-circumference of b into six equal parts at , , , etc.; draw the common tangent at a, upon which rectify the arc a by process no. ; then by process no. set out an equal arc a on the base circle, and stepping it off three times to the right and left, bisect these spaces, thus making subdivisions on the base circle equal in length to those on the rolling one. take in succession as radii the chords a , a , a , etc., of the describing circle, and with centres , , , etc., on the base circle, strike arcs either externally or internally, as shown respectively on the right and left; the curve tangent to the external arcs is the epicycloid, that tangent to the internal ones the hypocycloid, forming the face and flank of a tooth for the base circle. [illustration: fig. .] in the diagram, figure , we have shown a part of an ellipse whose length is ten inches, and breadth six, the figure being half size. in order to give an idea of the actual appearance of the combination when complete, we show in figure the pair in gear, on a scale of three inches to the foot. the excessive eccentricity was selected merely for the purpose of illustration. figure will serve also to call attention to another serious circumstance, which is, that although the ellipses are alike, the wheels are not; nor can they be made so if there be an even number of teeth, for the obvious reason that a tooth upon one wheel must fit into a space on the other; and since in the first wheel, figure , we chose to place a tooth at the extremity of each axis, we must in the second one place there a space instead; because at one time the major axes must coincide; at another, the minor axes, as in figure . if, then, we use even numbers, the distribution, and even the forms of the teeth, are not the same in the two wheels of the pair. but this complication may be avoided by using an odd number of teeth, since, placing a tooth at one extremity of the major axes, a space will come at the other. it is not, however, always necessary to cut teeth all round these wheels, as will be seen by an examination of figure , c and d being the fixed centres of the two ellipses in contact at p. now p must be on the line c d, whence, considering the free foci, we see that p b is equal to p c, and p a to p d; and the common tangent at p makes equal angles with c p and p a, as is also with p b and p d; therefore, c d being a straight line, a b is also a straight line and equal to c d. if then the wheels be overhung, that is, fixed on the ends of the shafts outside the bearings, leaving the outer faces free, the moving foci may be connected by a rigid link a b, as shown. [illustration: fig. .] this link will then communicate the same motion that would result from the use of the complete elliptical wheels, and we may therefore dispense with the most of the teeth, retaining only those near the extremities of the major axes, which are necessary in order to assist and control the motion of the link at and near the dead-points. the arc of the pitch-curves through which the teeth must extend will vary with their eccentricity; but in many cases it would not be greater than that which in the approximation may be struck about one centre; so that, in fact, it would not be necessary to go through the process of rectifying and subdividing the quarter of the ellipse at all, as in this case it can make no possible difference whether the spacing adopted for the teeth to be cut would "come out even" or not, if carried around the curve. by this expedient, then, we may save not only the trouble of drawing, but a great deal of labor in making, the teeth round the whole ellipse. we might even omit the intermediate portions of the pitch ellipses themselves; but as they move in rolling contact their retention can do no harm, and in one part of the movement will be beneficial, as they will do part of the work; for if, when turning, as shown by the arrows, we consider the wheel whose axis is d as the driver, it will be noted that its radius of contact, c p, is on the increase; and so long as this is the case the other wheel will be compelled to move by contact of the pitch lines, although the link be omitted. and even if teeth be cut all round the wheels, this link is a comparatively inexpensive and a useful addition to the combination, especially if the eccentricity be considerable. of course the wheels shown in figure might also have been made alike, by placing a tooth at one end of the major axis and a space at the other, as above suggested. in regard to the variation in the velocity ratio, it will be seen, by reference to figure , that if d be the axis of the driver, the follower will in the position there shown move faster, the ratio of the angular velocities being p Ã� d/p Ã� b; if the driver turn uniformly, the velocity of the follower will diminish, until at the end of half a revolution, the velocity ratio will be p Ã� b/p Ã� d; in the other half of the revolution these changes will occur in a reverse order. but p d = l b; if then the centres b d are given in position, we know l p, the major axis; and in order to produce any assumed maximum or minimum velocity ratio, we have only to divide l p into segments whose ratio is equal to that assumed value, which will give the foci of the ellipse, whence the minor axis may be found and the curve described. for instance, in figure the velocity ratio being nine to one at the maximum, the major axis is divided into two parts, of which one is nine times as long as the other; in figure the ratio is as one to three, so that the major axis being divided into four parts, the distance a c between the foci is equal to two of them, and the distance of either focus from the nearest extremity of the major axis is equal to one, and from the more remote extremity is equal to three of these parts. chapter xii. _plotting mechanical motions._ [illustration: fig. .] let it be required to find how much motion an eccentric will give to its rod, the distance from the centre of its bore to the centre of the circumference, which is called the throw, being the distance from a to b in figure . now as the eccentric is moved around by the shaft, it is evident that the axis of its motion will be the axis a of the shaft. then from a as a centre, and with radius from a to c, we draw the dotted circle d, and from e to f will be the amount of motion of the rod in the direction of the arrow. this becomes obvious if we suppose a lead pencil to be placed against the eccentric at e, and suppose the eccentric to make half a revolution, whereupon the pencil will be pushed out to f. if now we measure the distance from e to f, we shall find it is just twice that from a to b. we may find the amount of motion, however, in another way, as by striking the dotted half circle g, showing the path of motion of b, the diameter of this path of motion being the amount of lateral motion given to the rod. [illustration: fig. .] in figure is a two arm lever fast upon the same axis or shaft, and it is required to find how much a given amount of motion of the long arm will move the short one. suppose the distance the long arm moves is to a. then draw the line b from a to the axis of the shaft, and the line c the centre line of the long arm. from the axis of the shaft as a centre, draw the circle d, passing through the eye or centre e of the short arm. take the radius from f to g, and from e as a centre mark it on d as at h, and h is where e will be when the long arm moves to a. we have here simply decreased the motion in the same proportion as one arm is shorter than the other. the principle involved is to take the motion of both arms at an equal distance from their axis of motion, which is the axis of the shaft s. [illustration: fig. .] in figure we have a case in which the end of a lever acts directly upon a shoe. now let it be required to find how much a given motion of the lever will cause the shoe to slide along the line _x_; the point h is here found precisely as before, and from it as a centre, the dotted circle equal in diameter to the small circle at e is drawn from the perimeter of the dotted circle, a dotted line is carried up and another is carried up from the face of the shoe. the distance k between these dotted lines is the amount of motion of the shoe. in figure we have the same conditions as in figure , but the short arm has a roller acting against a larger roller r. the point h is found as before. the amount of motion of r is the distance of k from j; hence we may transfer this distance from the centre of r, producing the point p, from which the new position may be marked by a dotted circle as shown. [illustration: fig. .] in figure a link is introduced in place of the roller, and it is required to find the amount of motion of rod r. the point h is found as before, and then the length from centre to centre of link l is found, and with this radius and from h as a centre the arc p is drawn, and where p intersects the centre line j of r is the new position for the eye or centre q of r. [illustration: fig. .] in figure we have a case of a similar lever actuating a plunger in a vertical line, it being required to find how much a given amount of motion of the long arm will actuate the plunger. suppose the long arm to move to a, then draw the lines b c and the circle d. take the radius or distance f, g, and from e mark on d the arc h. mark the centre line j of the rod. now take the length from e to i of the link, and from h as a centre mark arc k, and at the intersection of k with j is where the eye i will be when the long arm has moved to a. [illustration: fig. .] in figure are two levers upon their axles or shafts s and s'; arm a is connected by a link to arm b, and arm c is connected direct to a rod r. it is required to find the position of centre g of the rod eye when d is in position e, and when it is also in position f. now the points e and f are, of course, on an arc struck from the axis s, and it is obvious that in whatever position the centre h may be it will be somewhere on the arc i, i, which is struck from the centre s'. now suppose that d moves to e, and if we take the radius d, h, and from e mark it upon the arc i as at v, then h will obviously be the new position of h. to find the new position of g we first strike the arc j, j, because in every position of g it will be somewhere on the arc j, j. to find where that will be when h is at v, take the radius h, g, and from v as a centre mark it on j, j, as at k, which is the position of g when d is at e and h is at v. for the positions when d is at f we repeat the process, taking the radius d, h, and from f marking p, and with the radius h, g, and from p as a centre marking q; then p is the new position for h, and q is that for g. [illustration: fig. .] in figure a lever arm a and cam c are in one piece on a shaft. s is a shoe sliding on the line _x_, and held against the cam face by the rod r; it is required to find the position of the face of the shoe against the cam when the end of the arm is at d. draw line e from d to the axis of the shaft and line f. from the shaft axis as a centre draw circle w; draw line j parallel to _x_. take the radius g h, and from k as a centre mark point p on w; draw line q from the shaft axis through p, and mark point t. from the shaft axis as a centre draw from t an arc, cutting j at v, and v is the point where the face of the shoe and the face of the cam will touch when the arm stands at d. [illustration: fig. .] let it be required to find the amount of motion imparted in a straight line to a rod attached to an eccentric strap, and the following construction may be used. in figure let a represent the centre of the shaft, and, therefore, the axis about which the eccentric revolves. let b represent the centre of the eccentric, and let it be required to find in what position on the line of motion _x_, the centre c of the rod eye will be when the centre b of the eccentric has moved to e. now since a is the axis, the centre b of the eccentric must rotate about it as denoted by the circle d, and all that is necessary to find the position of c for any position of eccentric is to mark the position of b on circle d, as at e, and from that position, as from e, as a centre, and with the length of the rod as a radius, mark the new position of c on the line _x_ of its motion. with the centre of the eccentric at b, the line q, representing the faces of the straps, will stand at a right angle to the line of motion, and the length of the rod is from b to c; when the eccentric centre moves to e, the centre line of the rod will be moved to position p, the line q will have assumed position r, and point c will have moved from its position in the drawing to g on line _x_. if the eccentric centre be supposed to move on to f, the point c will move to h, the radii b c, e g, and f h all being equal in length. now when the eccentric centre is at e it will have moved one-quarter of a revolution, and yet the point c will only have moved to g, which is not central between c and h, as is denoted by the dotted half circle i. [illustration: fig. .] on the other hand, while the eccentric centre is moving from e to f, which is but one-quarter of a revolution, the rod end will move from g to h. this occurs because the rod not only moves _endwise_, but the end connected to the eccentric strap moves towards and away from the line _x_. this is shown in the figure, the rod centre line being marked in full line from b to _x_. and when b has moved to e, the rod centre line is marked by dotted line e, so that it has moved away from the line of motion b _x_. in figure the eccentric centre is shown to stand at an angle of degrees from line _q_, which is at a right angle to the line of motion _x x_, and the position of the rod end is shown at c, j and h representing the extremes of motion, and g the centre of the motion. [illustration: fig. .] if now we suppose the eccentric centre to stand at t, which is also an angle of degrees to _q_, then the rod end will stand at k, which is further away from g than c is; hence we find that on account of the movement of the rod out of the straight end motion, the motion of the rod end becomes irregular in proportion to that of the eccentric, whose action in moving the eye c of the rod in a straight line is increased (by the rod) while it is moving through the half rotation denoted by v in figure, and diminished during the other half rotation. in many cases, as, for example, on the river steamboats in the western and southern states, cams are employed instead of eccentrics, and the principles involved in drawing or marking out such cams are given in the following remarks, which contain the substance of a paper read by lewis johnson before the american society of mechanical engineers. in figure is a side view of a pair of cams; one, c, being a full stroke cam for operating the valve that admits steam to the engine cylinder; and the other, d, being a cam to cut off the steam supply at the required point in the engine stroke. the positions of these cams with relation to the position of the crank-pin need not be commented upon here, more than to remark that obviously the cam c must operate to open the steam inlet valve in advance of cam d, which operates to close it and cause the steam to act expansively in the cylinder, and that the angle of the throw line of the cut-off valve d to the other cam or to the crank-pin varies according as it is required to cut off the steam either earlier or later in the stroke. [illustration: fig. .] the cam yoke is composed of two halves, y and y', bolted together by bolts b, which have a collar at one end and two nuts at the other end, the inner nuts n n enabling the letting together of the two halves of the yoke to take up the wear. it is obvious that as the shaft revolves and carries the cam with it, it will, by reason of its shape, move the yoke back and forth; thus, in the position of the parts shown in figure , the direction of rotation being denoted by the arrow, cam c will, as it rotates, move the yoke to the left, and this motion will occur from the time corner _a_ of the cam meets the face of y' until corner _b_ has passed the centre line _d_. now since that part of the circumference lying between points _a_ and _b_ of the cam is an arc of a circle, of which the axis of the shaft is the centre, the yoke will remain at rest until such time as _b_ has passed line _d_ and corner _a_ meets the jaw y of the yoke; hence the period of rest is determined by the amount of circumference that is made concentric to the shaft; or, in other words, is determined by the distance between _a_ and _b_. the object of using a cam instead of an eccentric is to enable the opening of the valves abruptly at the beginning of the piston stroke, maintaining a uniform steam-port opening during nearly the entire length of stroke, and as abruptly closing the valves at the termination of the stroke. figure is a top view of the mechanism in figure ; and figure shows an end view of the yoke. at b, in figure , is shown a guide through which the yoke-stem passes so as to be guided to move in a straight line, there being a guide of this kind on each side of the yoke. [illustration: fig. .] the two cams are bolted to a collar that is secured to the crank-shaft, and are made in halves, as shown in the figures and also in figures and , which represent cams removed from the other mechanism. to enable a certain amount of adjustment of the cams upon the collar, the bolts which hold them to the collar fit closely in the holes in the collar, but the cams are provided with oblong bolt holes as shown, so that the position of either cam, either with relation to the other cam or with relation to the crank-pin, can be adjusted to the extent permitted by the length of the oblong holes. [illustration: fig. .] the crank is assumed in the figures to be on its dead centre nearest to the engine cylinder, and to revolve in the direction of the arrows. the cams are so arranged that their plain unflanged surfaces bolt against the collar. the method of drawing or marking out a full stroke cam, such as c in figure , is illustrated in figure , in which the dimensions are assumed to be as follows: diameter of crank shaft, - / inches; travel of cam, inches; width of yoke, inches. [illustration: fig. .] the circumference of the cam is composed of four curved lines, p, p', k , and k . the position of the centre of the crank shaft in this irregularly curved body is at x. the arcs k and k differ in radius, but are drawn from the same point, x, and hence are concentric with the crank shaft. the arcs p, p', are of like radius, but are drawn from the opposite points s, s', shown at the intersection of the arcs p, p', with the arc k . thus arcs p, p', are eccentric to the crank shaft. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] to draw the cam place one point of the dividers at x, which is the centre of the crank shaft, and draw the circle e equal to width of yoke, inches. through this centre x, draw the two right lines a and b. on the line b, at the intersection of the curved line e, draw the two vertical lines a , a . with a radius of - / inches, and with one point of the dividers at x, draw the arc k . with a radius of - / inches, and one point of the dividers at x, draw the arc k . with a radius of inches, and one point of the dividers at the intersection of the arc e, with the vertical line a at s, draw the arc p opposite to s, and let it merge or lose itself in the curved line k . draw the other curved line p' from the other point s, and we have a full stroke cam of the dimensions required, and which is represented in figure , removed from the lines used in constructing it. [illustration: fig. .] the engravings from and including figure illustrate the lines embracing cut-off cams of varying limits of cut-off, but all of like travel and dimensions, which are the same as those given for the full stroke cam in figure . in drawing cut-off cams, the stroke of the engine plays a part in determining their conformation, and in the examples shown this is assumed to be feet. figure illustrates the manner of finding essential points in drawing or marking out cut-off cams. with x as a centre, and a radius of feet, draw the circle e , showing the path of the crank-pin in making a revolution. this circle has a diameter of feet, equal to the stroke of the engine. draw the horizontal line b, passing through the centre of circle e . within the limits of circle e , subdivide line b into eight equal parts, as at , , , , etc. draw the vertical lines, , , , , etc., until they each intersect the circle e . [illustration: fig. .] with x as a centre, draw the circle e, having a diameter of inches, equal to the space in the yoke embracing the cam. from the centre x draw the series of radial lines through the points of intersection of the vertical lines , , , , etc., from the circle e , and terminating at x. we will now proceed to utilize the scale afforded by figure , in laying off the cut-off cam shown in figure , of half stroke limit. [illustration: fig. .] with x as a centre, draw the circle e, figure , having a diameter of inches. bisect this circle with the straight lines a and b, which bear the same relation to their enclosing circle that the lines a, b, do to the circle e in figure . [illustration: fig. .] it will be observed, in figure , that the vertical line a is (at the top half) also no. , representing / , or half of the stroke. with a radius of inches, and one point of the dividers placed at v, which is at the intersection of the circle e with the horizontal line b in figure , draw the arc p. with the same radius and with one compass point rested at v', draw the arc p'; then two arcs, p and p', intersecting at the point s. with the same radius and one point of the compasses at s, draw the arc h h. the arcs k and k are drawn from the centre x, with a radius of - / for k and - / inches for k , and only serve in a half stroke cam to intersect the curved lines already drawn, as shown in figure . in practice, the sharp corner at s would be objectionable, owing to rapid wear at this point; and hence a modification of the dimensions for this half stroke cam would be required to obtain a larger wearing surface at the point s, but the cam of this limit ( / stroke) is correctly drawn by the process described with reference to figure , the outline of the cam so constructed being shown in figure . [illustration: fig. .] in figure is shown a cam designed to cut off the steam at five-eighths of the piston stroke, the construction lines being given in figure , for which draw circle e and straight lines a and b, as in the preceding example. by reference to figure it will be observed that the diagonal line drawn through circle e at is drawn from the straight line marked , which intersects circle e , and as this straight line represents five-eighths of the stroke laid off on line b, it determines the limit of cut-off on the five-eighths cam in figure . [illustration: fig. .] turning then to figure , take on circle e the radius from radial line to radial line , and mark it in figure from the vertical line producing v'. now, with a radius of inches, and one point of the dividers fixed at point v, forming the intersection of the circle e with the horizontal line b, draw the arc p. with the same radius, and one point of the dividers fixed at point v', draw the opposite arc p'. with a radius of - / inches from the centre x, draw the arc k , intersecting lines p p', at s s. with a radius of - / inches, draw the curved line k , opposite to curved line k . now, with a radius of inches, and one point of the dividers fixed alternately at s s, draw the arcs h, h, from their intersection with the circle e, until they merge into the curved line k . these curved lines embrace a cut-off cam of five-eighths limit, shown complete in figure . [illustration: fig. .] from the instructions already given it should be easy to understand that the three-fourths and seven-eighths cams, shown in figures , , and , are drawn by taking the points of their cut-off from the same scale shown in figure , at the diagonal points and , intersecting circle e in that figure; and cut-off cams of intermediate limit of cut-off can be drawn by further subdividing the stroke line b, in figure , into the required limits. [illustration: fig. .] cut-off cams of any limit are necessarily imperfect in their operations as to uniformity of cut-off from opposite ends of the slides, not from any defect in the rule for laying them off, but from the well-known fact of the crank pin travelling a greater distance, while driven by the piston from the centre of the cylinder, through its curved path from the cylinder, over its centre, and back to the centre of the cylinder, than in accomplishing the remaining distance of its path in making a complete revolution; and, although the subdivisions of eighths of the stroke line b, in figure , does not truly represent a like division of the piston stroke, owing to deviation, caused by inclination of the connecting rod in traversing from the centres to half stroke, still it will be found that laying off a cut-off cam by this rule is more nearly correct than if the divisions on stroke line b were made to correspond exactly with a subdivision of piston stroke into eighths. [illustration: fig. .] the cut-off in cams laid off by the rules herein described is greater in travelling from one side of the slides than in travelling from the opposite end, one cut-off being more than the actual cut-off of piston stroke, and the other less; and in practical use, owing to play or lost motion in the connections from cam to valve, the actual cut-off is less than the theoretical; hence cut-off cams are usually laid off to compensate for lost motion; that is, laid off with more limit; for instance, a five-eighths cam would be laid off to cut-off at eleven-sixteenths instead of five-eighths. [illustration: fig. .] figure represents the motion a crank, c, imparts to a connecting rod, represented by the thick line r, whose end, b, is supposed to be guided to move in a straight line. the circle h represents the path of the crank-pin, and dots , , , etc., are different crank-pin positions equidistant on the circle of crank-pin revolution. suppose the crank-pin to have moved to position , and with the compasses set to the length of the rod r, we set one point on the centre of position , and mark on the line of motion _m_ the line _a_, which will be the position rod end b will have moved to. suppose next that the crank-pin has moved into position , and with the compass point on the centre of we mark line , showing that while the crank-pin moved from to , the rod end moved from _a_ to _b_; by continuing this process we are enabled to discern the motion for the whole of the stroke. the backward stroke will be the same, for corresponding crank-pin positions, for both strokes; thus, when the rod end is at the crank-pin may be at or at . this fact enables us to find the positions for the positions later than , on the other side of the circle, as at , , , etc., which keeps the engraving clear. [illustration: fig. .] in figure a pinion, p, drives a gear-wheel, d, on which there is a pin driving the sliding die a in the link l, which is pivoted at c, and connected at its upper end to a rod, r, which is connected to a bolt, b, fast to a slide, s. it is required to find the motion of s, it moving in a straight line, dotted circle h' representing the path of the pin in the sliding die a, arc h representing the line of motion of the upper end of link l, and lines n, o, its centre line at the extreme ends of its vibrating motion. in figure the letters of reference refer to the same parts as those in figure . we divide the circle h' of pin motion into equidistant parts marked by dots, and through these we draw lines radiating from centre, c, and cutting arc h, obtaining on the arc h the various positions for end z of rod r, these positions being marked respectively , , , , etc., up to . with a pair of compasses set to the length of rod r from on h, as a centre, we mark on the line of motion of the slide, line _a_, which shows where the other end of rod r will be (or in other words, it shows the position of bolt b in figure ), when the centre of a, figure , is in position , figure . [illustration: fig. .] from on arc h, we mark with the compasses line _b_ on line m, showing that while the pin moved from to , the rod r would move slide s, figure , from _a_ to _b_, in figure . from we mark _c_, and so on, all these marks being above the horizontal line m, representing the line of motion, and being for the forward stroke. for the backward stroke we draw the dotted line from position up to arc h, and with the compasses at mark a line beneath the line m of motion, pursuing the same course for all the other pin motions, as , , etc., until the pin arrives again at position , and the link at o, and has made a full revolution, and we shall have the motion of the forward stroke above and that of the backward one below the line of motion of the slide, and may compare the two. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] figures and represent the whitworth quick return motion that is employed in many machines. f represents a frame supporting a fixed journal, b, on which revolves a gear-wheel, g, operated by a pinion, p. at a is an arm having journal bearing in b at c. this arm is driven by a pin, d, fast in the gear, g; hence as the gear revolves, pin d moves a around on c as a centre of motion. a is provided with a slot carrying a pin, x, on which is pivoted the rod, r. the motion of end n of the rod r being in a straight line, m, it is required to find the positions of n during twenty-four periods in one revolution of g. in figure let h' represent the path of motion of the driving pin d, about the centre of b, and h the path of motion of x about the centre c; these two centres corresponding to the centres of b and c respectively, in figure . let the line m correspond to the line of motion m in figure . now since it is the pin d, figure , that drives, and since its speed of revolution is uniform, we divide its circle of motion h' into twenty-four equal divisions, and by drawing lines radiating from centre c, and passing through the lines of division on h' we get on circle h twenty-four positions for the pin x in figure . then setting the compasses to the length of the rod (r, figure ), we mark from position on circle h as a centre line, _a_; from position on h we mark line _b_, and so on for the whole twenty-four positions on circle h, obtaining from _a_ to _n_ for the forward, and from _n_ to _y_ for the motion during the backward stroke. suppose now that the mechanism remaining precisely the same as before, the line m of motion be in a line with the centres c, b, instead of at a right angle to it, as it is in figure , and the motion under this new condition will be as in figure ; the process for finding the amount of motion along m from the motion around h being precisely as before. [illustration: fig. .] in figure is shown a cutter-head for a wood moulding machine, and it is required to find what shape the cutting edge of the cutter must be to form a moulding such as is shown in the end view of the moulding in the figure. now the line a a being at a right angle to the line of motion of the moulding as it is passed beneath the revolving cutter, or, what is the same thing, at a right angle to the face of the table on which the moulding is moved, it is obvious that the highest point c of the moulding will be cut to shape by the point c of the cutter; and that since the line of motion of the end of the cutter is the arc d, the lowest part of the cutter action upon the moulding will be at point e. it will also be obvious that as the cutter edge passes, at each point, its length across the line a a, it forms the moulding to shape, while all the cutting action that occurs on either side of that line is serving simply to remove material. all that we have to consider, therefore, is the action on line a a. it may be observed also that the highest point c of the cutter edge must not be less than / inch from the corner of the cutter head, which gives room for the nut n (that holds the cutter to the head) to pass over the top of the moulding in a - / inch head. in proportion as the heads are made larger, however, less clearance is necessary for the nut, as is shown in figure , the cutter edge extending to c, and therefore nearly up to the corner of the head. its path of motion at c is shown by dotted arc b, which it will be observed amply clears the nut n. in practice, however, point c is not in any size of cutter-head placed nearer than / inch from corner x of the cutter-head. to find the length of the cutter edge necessary to produce a given depth of moulding, we may draw a circle _i_, figure , equal in diameter to the size of the cutter head to be used, and line a a. the highest point of cutting edge being at _e_, and the lowest at g, then circles _d_ and _f_ represent the line of motion of these two points; and if we mark the cutter in, the necessary length of cutting edge on the cutter is obviously from _a_ to _b_. [illustration: fig. .] [illustration: fig. .] now the necessary depth of cutter edge being found for any given moulding, or part of a moulding, the curves for the edge may be found as follows: suppose the moulding is to be half round, as in the end view in figure . the width of the cutter must of course equal the width of the moulding, and the length or depth of cutting edge required may be found from the construction shown in figure ; hence all that remains is to find the curve for the cutting edge. in figure , let a a represent the centre of the cutter width, its sides being f f', and its end b b. from centre c draw circle d, the upper half of which will serve to represent the moulding. mark on a the length or depth the cutting edge requires to be, ascertaining the same from the construction shown in figure , and mark it as from c to k'. then draw line e e, passing through point k. draw line g, standing at the same angle to a a as the face _h b_, figure , of the cutter does to the line a a, and draw line h h, parallel to g. from any point on g, as at i, with radius j, draw a quarter of a circle, as k. mark off this quarter circle into equal points of division, as by , , , etc., and from these points of division draw lines, as _a_, _b_, _c_, etc.; and from these lines draw horizontal lines _d_, _e_, _f_, etc. now divide the lower half of circle d into twice as many equal divisions as quarter circle k is divided into, and from these points of division draw perpendiculars _g_, _h_, _i_, etc. and where these perpendiculars cross the horizontal lines, as _d_, will be points through which the curve may be drawn, three of such points being marked by dots at _p_, _q_, _r_. if the student will, after having drawn the curve by this construction, draw it by the construction that was explained in connection with figure , he will find the two methods give so nearly identical curves, that the latter and more simple method may be used without sensible error. [illustration: fig. .] [illustration: fig. .] when the curves of the moulding are not arcs of circles they may be marked as follows: take the drawing of the moulding and divide each member or step of it by equidistant lines, as _a_, _b_, _c_, _d_, _e_, _f_, _g_, in figure ; above the moulding draw lines representing the cutter, and having found the depth of cutting edge for each member by the construction shown in figure , finding a separate line, _a b_, for each member of the moulding, transfer the depths so found to the face of the cutter; divide the depth of each member of the cutter into as many equal divisions as the corresponding member of the moulding is divided into, as by lines _h_, _i_, _j_, _k_, _l_, _m_, _n_. then draw vertical lines, as _o_, _p_, _q_, _r_, etc.; and where these lines meet the respective lines _h_, _i_, _j_, etc., are points in the curve, such points being marked on the cutter by dots. chapter xiii. _examples in line-shading and drawings for line-shaded engravings._ although in workshop drawings, line-shading is rarely employed, yet where a design rather than the particular details of construction is to be shown, line-shading is a valuable accessory. figure , for example, is intended to show an arrangement of idle pulleys to guide belts from one pulley to another; the principle being that so long as the belt passes to a pulley moving in line with the line of rotation of the pulley, the belt will run correctly, although it may leave the pulley at considerable angle. when a belt envelops two pulleys that are at a right angle to each other, two guide pulleys are needed in order that the belt may, in passing to each pulley, move in the same plane as the pulley rotates in, and the belt is in this case given what is termed a quarter twist. it will be observed that by the line-shading even the twist of the belt is much more clearly shown than it would be if left unshaded. an excellent example of shading is given in figure , which is extracted from the _american machinist_, and represents a cutting tool for a planing machine. the figure is from a wood engraving, but the effect may be produced by lines, the black parts being considered as simply broad black lines. [illustration: fig. .] the drawings from which engravings are made are drawn to conform to the process by which the engraving is to be produced. drawings that are shaded by plain lines may be engraved by three methods. first, the drawing may be photo-engraved, in which process the drawing is photographed on the metal, and every line appears in the engraving precisely as it appears in the drawing. [illustration: fig. .] for this kind of engraving the drawing may be made of any convenient size that is larger than the size of engraving to be produced, the reduction of size being produced in the photographing process. drawings for photo-engraving require to have the lines jet black, and it is to be remembered that if red centrelines are marked on the drawing, they will be produced as ordinary black lines in the engraving. the shading on a drawing to be photo-engraved must be produced by lines, and not by tints, for tints, whether of black or of colors, will not photo-engrave properly. it is generally preferred to make the drawing for a photo-engraving larger than the engraving that is to be made from it, a good proportion being to make the drawing twice the length the engraving is to be. this serves to reduce the magnitude of any roughness in the lines of the drawing, and, therefore, to make the engraving better than the drawing. the thickness of the lines in the drawing should be made to suit the amount of reduction to be made, because the lines are reduced in thickness in the same proportion as the engraving is reduced from the drawing. thus the lines on an engraving reduced to one-half the dimensions of the drawing would be one-half as thick as the lines on the drawing. drawings for photo-engraving should be made on smooth-faced paper; as, for example, on bristol board; and to make the lines clean and clear, the drawing instruments should be in the best of condition, and the paper or bristol board quite dry. the india rubber should be used as little as possible on drawings to be photo-engraved, because, if used before the lines are inked in, it roughens the surface of the paper, and the inking lines will be less smooth and even at their edges; and for this reason it is better not to rub out any lines until all the lines have been inked in. if used to excess after the lines have been inked in it serves to reduce the blackness of the lines, and may so pale them that they will not properly photo-engrave. to make a drawing for an engraver in wood it would be drawn directly on the face of the box-wood block, on which it is to be engraved. the surface of the block is first whitened by a white water color, as chinese white. if the drawing that is to be used as a copy is on sufficiently thin paper, its outline may be traced over by pencil lines, and the copy may then be laid face down on the wood block and its edges held to the block by wax, the pencilled lines being face to the block. the outline may then be again traced over with a pencil or pointed instrument, causing the imprint of the lead pencil lines to be left on the whitened surface of the block. if the copy is on paper too thick to be thus employed, a tracing may be made and used as above; it being borne in mind that the tracing must be laid with the pencilled lines on the block, because what is the right hand of the drawing on the block is the left hand in the print it gives. the shading on wood blocks is given by tints of india ink aided by pencilled lines, or of course pencilled lines only may for less artistic work be used. another method is to photograph the drawing direct upon the surface of the wood block; it is unnecessary, however, to enter into this part of the subject. the third method of producing an engraving from a drawing is by means of what is known as the wax process. drawings for this process should be made on thin paper, for the following reasons: the process consists, briefly stated, in coating a copper plate with a layer of wax about / inch deep, and in drawing upon the wax the lines to compose the engraving, which lines are produced by means of tools that remove the wax down to the surface of the copper. the plate and wax are then placed in a battery and a deposit of copper fills in the lines and surface of the wax, thus forming the engraving. now if the drawing is made on thin paper, the engraver coats the surface of the drawing with a dry red pigment, and with a pointed instrument traces over the lines of the drawing, which causes them to leave a red imprint on the surface of the wax, and after the drawing is removed the engraver cuts these imprinted lines in the wax. if the drawing is on thick paper, this method of transferring the drawing to the wax cannot be used, and the engraver may take a tracing from the drawing and transfer from the tracing to the wax. it is obvious, also, that for wax engravings the drawing should be made of the same size that the engraving is required to be, or otherwise the tracing process described cannot be used. figure represents an engraving made by the wax process from a print from a wood engraving, and it is obvious that since all the lines drawn on the wax sink down to the surface of the copper plate, the shading is virtually composed of lines, the black surfaces being where the lines have been sufficiently close together and broad to remove all the wax enclosed within those surfaces. [illustration: fig. .] [illustration: fig. .] the wax process is, however, more suitable for engravings in plain outline only, and is especially excellent when the parts are small and the lines fall close together; as, for example, in figures and , which are engravings of a boiler drilling machine, and were produced for the _american machinist_ by tracing over a wood engraving from london, "engineering" in the manner already described. the fineness and cleanness of the lines in the wax process is here well illustrated, the disposition of the parts being easily seen from the engraving, and easily followed in connection with the following description: the machine consists of two horizontal bed-plates a and a , made with $v$ slides on top, and placed at right angles to each other. upon each of the bed-plates is fitted a vertical arm b and b , each of which carries two saddles, c and c , these being each adjustable vertically on its respective arm by means of rack and pinion and hand wheels d and d . the saddles are balanced so that the least possible exertion is sufficient to adjust them. the vertical arms, b and b , are cast each with a round foot by which the arms are attached to the square boxes e and e , which are fitted to the $v$ slides on the horizontal beds a and a , and are adjustable thereon by means of screw and ratchet motion f and f . each of the square boxes has cast on it a small arm g and g , carrying studs upon which run pinions gearing into the circular racks at the foot of the vertical arms. the square boxes have each a circular groove turned in the top to receive the bolts by which the vertical arms are connected to them, and thus the vertical arms, and with them the drill spindles n and n , are adjustable radially with the boiler--the adjustment being effected by means of the pinions and circular racks. the pinions are arranged so that they can be worked with the same screw key that is used for the bolts in the circular grooves. the shell to be drilled is placed upon the circular table h, which is carried by suitable framework adjustable by means of screw on a $v$ slide i, placed at an angle of ° with the horizontal bed-plates. by this arrangement, when the table is moved along i, it will approach to or recede from all the drills equally. j and j are girders forming additional bearings for the framework of the table. the bed-plates and slides for the table are bolted and braced together, making the whole machine very firm and rigid. power is applied to the machine through the cones k and k , working the horizontal and vertical shafts l and l , etc. on the vertical shafts are fitted coarse pitch worms sliding on feather keys, and carried with the saddles c and c , etc. the worms gearing with the worm wheels m and m are fitted on the sleeves of the steel spindles n and n . the spindles are fitted with self-acting motions o and o , which are easily thrown in and out of gear. the machine is also used for turning the edge of the flanges which some makers prefer to have on the end plates of marine boilers. the plates are very readily fixed to the circular table h, and the edge of the flange trued up much quicker than by the ordinary means of chipping. when the machine is used for this purpose, the cross beam p, which is removable, is fastened to the two upright brackets r and r . the cross beam is cast with $v$ slides at one side for a little more than half its length from one end, and on the opposite side for the same length, but from the opposite end. the $v$ slides are each fitted with a tool box s and s , having a screw adjustment for setting the tool to the depth of cut, and adjustable on the $v$ slides of the cross beam to the diameter of the plate to be turned. this arrangement of the machine is also used for cutting out the furnace mouths in the boiler ends. the plate is fastened to the circular table, the centre of the hole to be cut out being placed over the centre of table; one or both of the tool boxes may be used. there is sufficient space between the upright brackets r and r , to allow that section of a boiler end which contains the furnace mouths to revolve while the holes are being cut out; the plate belonging to the end of a boiler of the largest diameter that the machine will take in for drilling. the holes cut out will be from feet inches in diameter and upwards. power for using the turntable is applied through the cone t. the bevel wheels, worms, worm wheels, and pinions for driving the tables are of cast steel, which is necessary for the rough work of turning the flanges. [illustration: fig. . (page .)] as to the practical results of using the machine, the drills are driven at a speed of feet per minute at the cutting edges. a jet of soapsuds plays on each drill from an orifice / in. in diameter, and at a pressure of lbs. per square inch. a joint composed of two -inch plates, and having holes and one-eighth in. in diameter, can be drilled in about - / minutes, and allowing about half a minute for adjusting the drill, each drill will do about holes per hour. the machine is designed to stand any amount of work that the drills will bear. the time required for putting on the end of a boiler and turning the flange thereon (say feet diameter) is about - / hours; much, however, depends on the state of the flanges, as sometimes they are very rough, while at others very little is necessary to true them up. the time required for putting on the plate containing the furnace mouths and cutting out three holes feet in. in diameter, the plate being and one-eighth in. thick, is three hours. of course, if several boilers of one size are being made at the same time, the holes in two or more of these plates can be cut out at once. the machine is of such design that it can be placed with one of the horizontal bed-plates (say a ), parallel and close up to a wall of the boiler shop; and when the turning apparatus is being used, the vertical arm b can be swiveled half way round on its square box e , and used for drilling and tapping the stay holes in marine boiler ends after they are put together; of course sufficient room must be left between bed-plate a , and the wall of boiler shop parallel with it, to allow for reception of the boiler to be operated upon. it would obviously be quite difficult to draw such drawings as in figures and on thin paper, so as to enable the drawing to be traced on the wax direct by the process before described, unless indeed the draftsman had considerable experience in fine work; hence, it is not uncommon to make the drawing large, and on ordinary drawing paper. the engraver then has the drawing photographed on the surface of the wax, and works to the photograph. the letters of reference in wax engravings are put in by impressing type in the wax, and in this connection it may be remarked that the letters i and o should not be used on drawings to be engraved by the wax process, unless they are situated outside the outlines of the drawing, because the i looks so much like part of a dotted line that it is often indistinguishable therefrom, while the o looks like a circle or an ellipse. chapter xiv. _shading and coloring drawings._ the shading or coloring of drawings by tints is more employed in large drawings than in small ones, and in europe than in the united states; while on the other hand tinting by means of line-shading is more employed in the united states than in europe, and more on small drawings than on large ones. many draftsmen adopt the plan of coloring the journals of shafts, etc., with a light tint, giving them the deepest tint at the circumference to give them a cylindrical appearance. this makes the drawing much clearer and takes but little time to do, and is especially advantageous where the parts are small or on a small scale, so that the lines are comparatively close together. for simple shading purposes black tints of various degrees of darkness may be employed, but it is usual to tint brass work with yellow. cast iron with india ink, wrought iron with prussian blue, steel with as light purple tint produced by mixing india ink, prussian blue and a tinge of crimson lake. copper is tinted red. on plane surfaces an even tint of color is laid, but if the surfaces are cylindrical they are usually colored deeper at and near the circumference, and are tinted over the colors with light tints of india ink to show their cylindrical form. if a drawing is to be colored or shaded with india ink the paper should be glued all around its edges to the drawing board, and then dampened evenly all over with a sponge, which will cause the paper to shrink and lay close to the surface of the drawing board. if, in applying a color or a tint, the color dries before the whole surface is colored, the color will not be of an equal shade; hence it is necessary before applying the color to dampen the surface, if it is a large one, so that the color at one part shall not get dry before there has been time to go over the whole surface; a more even depth of color is attained by the application of several coats of a light tint, than with one coat, giving the full depth of color. but if the paper is not allowed to dry sufficiently between the coats, or if it has been made too wet previous to the application of the colors, it will run in places, leaving other hollows into which the color will flow, making darker-colored spots. to avoid this the paper may be dried somewhat by the application of clean blotting paper. to maintain an even shade of color, it is necessary to slightly stir up the color each time the brush is dipped into the color saucer or palette, especially when the coloring is composed of mixed colors, because the coloring matter is apt to separate from the water and sink to the bottom. so, also, in mixing colors it is best to apply the end of the color to the surface of the palette and not to apply the brush direct to the cake of color, because the color is more completely mixed by contact with the palette than it can be by the brush, which may retain a speck of color that will, unless washed out, make a streak upon the drawing. to graduate the depth of tint for a cylindrical surface, it is best to mix several, as, say three depths or degrees of tint, and to first use the darkest, applying it in the direction in which the piece is to be shaded darkest. the width this dark application should be is obviously determined by the diameter of the piece. the next operation is to lighten or draw the part, line or streak thus dark colored, causing it to get paler and paler as it approaches the axial line of the piece or cylinder. this lightening is accomplished as follows: the dark streak is applied along such a length of the piece that it will not dry before there has been time to draw it out or lighten it on the side towards the axis. a separate brush may then be wetted and drawn along the edge of the dark streak in short strokes, causing the color to run outwards and become lighter as it approaches the axis. it will be found that during this process the brush will occasionally require washing in water, because from continuous contact with the dark streak the tint it contains will darken. when the first coat has been laid and spread or drawn out from end to end of the piece, the process may be repeated two or three times, the most even results being obtained by making the first dark streak not too dark, and going over the drawing several times, but allowing the paper to get very nearly dry between each coat. in small cylindrical bodies, as, say / inch in diameter, the darkest line of shadow may be located at the lines representing the diameter of the piece, but in pieces of larger diameter the darkest line may be located at a short distance from the line that denotes the diameter or perimeter on the shadow or right-hand side of the piece, as is shown in many of the engravings that follow. it is obvious that if a drawing is to have dimensions marked on it, the coloring or tinting should not be deep enough to make it difficult to see the dimension figures. the size of the brush to be used depends, of course, upon the size of the piece to be shaded or colored, and it is best to keep one brush for the dark tint and to never let the brush dry with the tint in it, as this makes it harsh. in a good brush the hairs are fine, lie close together when moistened, are smooth and yet sufficiently stiff or elastic to bend back slightly when the pressure is removed. if, when under pressure and nearly dry, the hairs will separate or the brush has no elasticity in it, good results cannot be obtained. all brushes should be well dried after use. the light in shading is supposed to come in at the left-hand corner of the drawing, as was explained with reference to the shade line. excellent examples to copy and shade with the brush are given as follows: figure represents a medart pulley, constructed by the hartford steam engineering company; the arms and hub are cast in one piece, and the rim is a wrought iron band riveted to the arms, whose ends are turned or ground true with the hub bore. the figure is obviously a wood engraving, but it presents the varying degrees of shade or shadow with sufficient accuracy to form a good example to copy and brush shade with india ink. figure represents a similar pulley with a double set of arms, forming an excellent example in perspective drawing, as well as for brush-shading. [illustration: fig. .] in brush-shading as with line-shading, the difficulties increase with an increase in the size of the piece, and the learner will find that after he has succeeded tolerably well in shading these small pulleys, it will be quite difficult, but excellent practice to shade the large pulley in figure . one of the principal considerations is to not let the color dry at the edges in one part while continuing the shading in another part of the same surface, hence it is best to begin at the edge or outline of the drawing and carry the work forward as quickly as possible, occasionally slightly wetting with water edges that require to be left while the shading is proceeding in another direction. [illustration: fig. .] when it is required to show by the shading that the surfaces are highly polished, the lighter parts of the shading are made to contain what may be termed splashes of lighter and darker shadow, as in figure , which represents an oil cup, having a brass casing enclosing a glass cylinder, which appears through the openings in the brass shell. figure represents an iron planing machine whose line-shading is so evenly effected that it affords an excellent example of shading. its parts are similar to those shown in the iron planer in figure , save that it carries two sliding heads, so as to enable the use, simultaneously, of two cutting tools. [illustration: fig. . (page .)] [illustration: fig. .] a superior example in shading is shown in figures and , which represent a plan and a sectional view of the steam-cylinder of a blake's patent direct-acting steam-pump. the construction of the parts is as follows: a is the steam-piston, h and h are the cylinder steam-passages; m is the cylinder exhaust port. [illustration: fig. .] [illustration: fig. .] the main valve, whose movement alternately opens the ports for the admission of steam to, and the escape of steam from, the main cylinder, is divided into two parts, one of which, c, slides upon a seat on the main cylinder, and at the same time affords a seat for the other part, d, which slides upon the upper face of c. as shown in the engravings, d is at the left-hand end of its stroke, and c at the opposite or right-hand end of its stroke. steam from the steam-chest, j, is therefore entering the right-hand end of the main cylinder through the ports e and h, and the exhaust is escaping through the ports h , e , k and m, which causes the main piston a to move from right to left. when this _piston_ has nearly reached the left-hand end of its cylinder, the tappet arm, t, attached to the piston-rod, comes in contact with, and moves the valve rod collar o and valve rod p, and thus causes c, together with the supplemental valves r and s s , which form, with c, _one casting_, to be moved from right to left. this movement causes steam to be admitted to the left-hand end of the supplemental cylinder, whereby its piston b will be forced towards the right, carrying d to the opposite or right-hand end of its stroke; for the movement of s closes n (the steam-port leading to the right-hand end), and the movement of s opens n (the steam-port leading to the opposite or left-hand end), at the same time the movement of v opens the right-hand end of this cylinder to the exhaust, through the exhaust ports x and z. the parts c and d now have positions opposite to those shown in the engravings, and steam is therefore entering the main cylinder through the ports e and h , and escaping through the ports h, e, k and m, which causes the main piston a to move in the opposite direction, or from left to right, and operations similar to those already described will follow, when the piston approaches the right-hand end of its cylinder. by this simple arrangement the pump is rendered positive in its action; that is, it will instantly start and continue working the moment steam is admitted to the steam-chest, while at the same time the piston is enabled to move as slowly as the nature of the duty may require. it will be noted that in figure , the ports of c are shown through d, whose location is marked by dark shading. this obviously is not correct, because d being above c should be shaded lighter than c, and again the ports e and k could not show dark through the port d. they might, of course, be shown by dotted outlines, but they would not appear to such advantage, and on this account it is permissible where artistic effect is sought, the object being to subserve the shading to making the mechanism and its operation clearly and readily understood. [illustration: fig. .] figure affords another excellent example for shading. it consists of an independent condenser, whose steam-cylinder and valve mechanism is the same as that described with reference to figures and . [illustration: fig. . (page .)] [illustration: fig. . (page .)] [illustration: fig. . (page .)] [illustration: fig. --section of cylinder and steam chest. (page .)] chapter xv. _examples in engine work._ in the figures from to inclusive are given three examples in engine work, all these drawings being from _the american machinist_. figures to represent drawings of an automatic high speed engine designed and made by professor john e. and william a. sweet, of syracuse, new york. figure is a side and an end view of the engine. upon a bed-plate is bolted two straight frames, between which, at their upper ends, the cylinder is secured by bolts. the guides for the cross-head are bolted to the frame, which enables them to be readily removed to be replaned when necessary. the hand wheel and rod to the right are to operate the stop-cock for turning on and off the steam to the steam-chest. the objects of the design are as follows: figure is a vertical section of the cylinder through the valve face, also showing the valve in section, and it will be seen that the lower steam passage enters the cylinder its full depth below the inside bottom, and that the whole inside bottom surface of the cylinder slopes or inclines towards the entrance of this passage. the object of this is to overcome the difficulty experienced from the accumulation of water in the cylinder, which, in the vertical engine, is usually a source of considerable annoyance and frequently the cause of accident. any water that may be present in the bottom finds its way by gravity to the port steam entrance, and is forced out by and with the exhaust steam at or before the commencement of the return stroke. to assist in the escape of water from the top of the cylinder, the piston is made quite crowning at that end, the effect of which is to collect the water in a narrow band, instead of spreading it over a large surface. this materially assists in its escape, and at the same time presents a large surface for the distribution of any water that may not find its way out in advance of the piston. the piston is a single casting unusually long and light, and is packed with four spring rings of / inch square brass wire. the valve is a simple rectangular plate, working between the valve face and a cover plate, the cover plate being held in its proper position, relative to the back of the valve, by steam pressure against its outer surface, and by resting against loose distance pieces between its inner surface and the valve seat. this construction admits of the valve leaving the seat, if necessary, to relieve the cylinder from water, as in the instance of priming, and also, by the reduction of these pieces, admits of ready adjustment to contact, should it become necessary. [illustration: fig. --valve motion.] the cover plate is provided with recesses on its inner surface which exactly correspond with the ports in the valve face, and the corresponding ports and recesses are kept in communication with each other by means of relief passages in the valve. from this it will be seen that the valve is subjected to equal and balanced pressure on each of its sides, and hence, is in equilibrium. the valve is operated through the valve motion, shown in figure , the eccentric rod of which hooks on a slightly tapered block that turns on the pin of the rock arm, like an ordinary journal box. the expansion, or cut-off, is automatically regulated by the operation of the governor in swinging the slotted eccentric in a manner substantially equivalent to moving it across the shaft, but is however favorably modified by the arrangement of the rock arm, which, in combination with the other motions, neutralizes the unfavorable operation of the usual shifting eccentric, and which, in connection with the large double port opening, provides for a good use of steam from to / stroke. the governor shown in figure is of the disc and single ball type, the centrifugal force of the ball being counteracted by a powerful spring. friction is reduced to a minimum in the governor connection, by introducing steel rollers and hardened steel plates in such a manner as to provide rolling instead of sliding motion. in order that a governor shall correctly perform its functions, it is unquestionably necessary that it have power largely in excess of the work required of it, and also that the friction shall represent a very low percentage of that power. in respect to this, especial means have been employed to reduce the friction; the valve being balanced, requires but little power to move it, while the governor ball being made heavy for the purpose of counterbalancing the weight of the eccentric and strap, its centrifugal force when the engine is at full speed is enormous, the spring to counteract it having to sustain from _two to three thousand pounds_. under these circumstances, as might be expected, the regulation is remarkably good. this is a very important consideration in an engine working under the conditions of a roll-train engine. [illustration: fig. --governor.] [illustration: fig. --section of pillow block.] figure represents a section of the pillow block box, crank-pin and wheel, together with the main journal. it will be seen that the end of the box next the crank wheel has a circular groove around its outside, and that a corresponding groove in the crank wheel projects over this groove. from this latter groove an oil hole of liberal size extends, as shown, to the surface of the crank-pin. any oil placed at the upper part of the groove on the box finds its way by gravity into the groove in the crank wheel, and is carried by centrifugal force to the outside surface of the crank-pin; so that whatever other means of lubrication may be employed, this one will always be positive in its action. this cut also shows the manner in which the box overlaps the main journal and forms the oil reservoir. [illustration: fig. --connecting rod. (page .)] another feature in the construction of this box is the means by which it is made to adjust itself in line with the shaft. it will be observed that it rests on the bottom of the jaws of the frame on two inclined surfaces, which form equal angles with the axis of the shaft when in its normal position, and that by moving longitudinally in either direction, as may be necessary, the box will accommodate itself to a change in the alignment of the shaft. in order that it may be free to move for this purpose it is not fitted with the usual fore and aft flanges. by this means any slight derangement, as in either the outboard or inboard bearing wearing down the fastest, is taken care of, the movement of the box on the inclined surfaces being for this purpose equivalent to the operation of a ball and socket bearing. figure gives a side and an edge view of the connecting rod, the rod being in section in the edge view, and the brasses in section lined in both views. the cross-head pin, it will be observed, is tapered, and is drawn home in the cross-head by a bolt; the sides of the pin are flattened somewhat where the journal is, so that the pin may not wear oval, as it is apt to do, because of the pull and thrust strain of the rod brasses falling mainly upon the top and bottom of the journal, where the most wear therefore takes place. the brasses at the crossed end are set up by a wedge adjustable by means of the screw bolts shown. the cross-head wrist pin being removable from the cross-head enables the upper end of the rod to have a solid end, since it can be passed into place in the crossed and the wrist pin inserted through the two. the lower ends of the connecting-rod and the crank-pin possess a peculiar feature, inasmuch as by enlarging the diameter of the crank-pin, the ends of the brasses overlap, to a certain extent, the ends of the journal, thus holding the oil and affording increased lubrication. the segments that partly envelop the cross-head pin and crank-pin, and are section lined in two directions, producing crossing section lines, or small squares, show that the brasses are lined with babbitt metal, which is represented by this kind of cross-hatching. these drawings are sufficiently open and clear to form very good examples to copy and to trace on tracing paper. [illustration: fig. .] [illustration: fig. . (page .)] [illustration: fig. .] figures , and represent, in place upon its setting, a horse-power horizontal steam-boiler for a stationary engine, and are the design of william h. hoffman. the cross-sectional view of the boiler shell in figure shows the arrangement of the tubes, which, having clear or unobstructed passages between the vertical rows of tubes, permits the steam to rise freely and assists the circulation of the water. the dry pipe (which is also shown in figure ) is a perforated pipe through which the steam passes to the engine cylinder, its object being to carry off the steam as dry as possible; that is to say, without its carrying away with the steam any entrained water that may be held in suspension. figure is a side elevation with the setting shown in section, and figure is an end view of the boiler and setting at the furnace end. the boiler is supported on each side by channel iron columns, these being riveted to the boiler shell angle pieces which rest upon the columns. the heat and products of combustion pass from the furnace along the bottom of the boiler, and at the end pass into and through the tubes and thence over the top of the boiler to the chimney flue. there is shown in the bridge wall an opening, and its service is to admit air to the gases after they have passed the bridge wall, and thus complete the combustion of such gases as may have remained unconsumed in the furnace. the cleansing door at one end and that lined with asbestos at the other, are to admit the passage of the tube cleaners. the asbestos at the top of the boiler shell is to protect it from any undue rise in temperature, steam being a poorer conductor of heat than water, and it being obvious that if one side of the boiler is hotter than the other it expands more from the heat and becomes longer, causing the boiler to bend, which strains and weakens it. the sides of the setting are composed of a double row of brick walls with an air space of three inches between them, the object being to prevent as far as possible the radiation of heat from the walls. the brick-staves are simply stays to hold the brick work together and prevent its cracking, as it is apt, in the absence of staying, to do. [illustration: fig. . (page .)] figures from to are working drawings of a -horse engine, designed also by william h. hoffman. figure represents a plan and a side view of the bed-plate with the main bearing and the guide bars in place. the cylinder is bolted at the stuffing box end to the bed-plate, and is supported at the outer end by an expansion link pivoted to the bed-plate. the main bearing is provided with a screw for adjusting the height of the bottom piece of the bearing, and thus taking up the wear. the guide bars are held to the bed in the middle as well as at each end. figures and represent cross sections of the bed-plate. [illustration: fig. --cross section of bed plate near junction with cylinder. (page .)] [illustration: fig. .] [illustration: fig. -- h.p. horizontal steam-engine--elevation of cylinder--scale - / " = foot. (page .)] [illustration: fig. -- h.p. horizontal steam-engine--end view of cylinder--scale - / " = foot. (page .)] figure represents a side elevation of the cylinder, and figure an end view of the same, the expansion support being for the purpose of permitting the cylinder to expand and contract under variations of temperature without acting to bend the bed-plate, while at the same time the cylinder is supported at both ends. the cylinder and cylinder covers are jacketted with live steam in the steam-spaces shown. [illustration: fig. -- h.p. engine--outside view of cylinder and steam-chest. (page .)] [illustration: fig. --sectional view of cylinder and valves--scale - / inches = foot. (page .)] [illustration: fig. --plan of cut-off device. (page .)] [illustration: fig. --working drawing of h.p. engine--details of main valve motion--scale " = foot. (page .)] [illustration: fig. -- h.p. horizontal steam-engine--cross head. (page .)] [illustration: fig. . fig. _a_. working drawings of h.p. steam engine--eccentric and eccentric strap--scale: " = foot. (page .)] [illustration: fig. -- h.p. horizontal steam-engine--connecting rod. (page .)] a view of the steam-chest side of the cylinder is given in figure , and a horizontal cross section of the cylinder, the steam-chest and the valves, is shown in figure . the main valves are connected by a right and left hand screw, to enable their adjustment, as are also the cut-off valves. figures and show the cam wrist plate and the cut-off mechanism. the cam wrist plate, which is of course vibrated by the eccentric rod, has an inclined groove, whose walls are protected from wear by steel shoes. in this groove is a steel roller upon a pin attached to the bell crank operating the main valve stem. the operation of the groove is to accelerate the motion imparted from the eccentric to the valve at one part of the latter's travel, and retard it at another, the accelerated portion being during the opening of the port for steam admission, and during its closure for cutting off, which enables the employment of a smaller steam-port than would otherwise be the case. the shaft for the cam plate is carried in a bearing at one end, and fits in a socket at the other, the socket and bearing being upon a base plate that is bolted to the bed-plate of the engine; a side view of the construction being shown in figure . figure represents the cross-head, whose wrist pin is let into the cross-head cheeks, so that it may be removed to be turned up true. the clip is to prevent the piston rod nut from loosening back of itself. figure represents a side view; and figure _a_ a section through the centre of the eccentric and strap. [illustration: fig. --working drawing of h.p. steam-engine.--wrist plate.-- " = foot.] the eccentric is let into the strap and is provided with an eye to receive a circular nut by means of which the length of the eccentric rod may be adjusted, a hexagon nut being upon the other or outer end of the eye. figure shows the construction of the connecting rod, the brasses of which are adjustable to take up the wear and to maintain them to correct length, notwithstanding the wear, by means of a key on each side of each pair of brasses, the keys being set up by nuts and secured by check nuts. index. ames' lathe feed motion, drawing a part of, . angle of three lines, one to the other, to find, , . of two lines, one to the other, to find, , , . angles, acute and obtuse, . arc of a circle, an, . arcs, construction with four, , . arcs for the teeth of wheels, to draw, . arrangement of different views, - . automatic high speed engine, drawings of, . axis of a cylinder, . of an ellipse, . ball or sphere, representation of by line-shading, , . bed-plate, cross section of, . plan and side view of, with main bearing and guide bars, . bell-mouthed body, representation of by line-shading, , . bevelled gear, one-half of, and an edge view projected from the same, . one of which is line-shaded, . wheels, . bevelled gears, small, . bevelled wheels, a pair of, in section, . bisected line, . black lines of a drawing, how to produce, . blacksmith, drawings for the, . blake's patent direct acting steam pump, , . boiler drilling machine, a, , . boiler, end view of, . shell, sectional view of, . bolt heads and nuts, united states standard, , . to draw a square-headed, . with a hexagon head, to draw. , . with a square under the head, . bolts and nuts, dimensions of united states standard, . united states standard, forged or unfinished, . bolts, nuts and polygons, examples in, - . bow pen, applying the ink to, . large, with a removable leg, . brass, representation of, by cross-hatching, . bread for rubbing out, . bristol board, use of rubber on, . brush-shading, . brushes, size and use of, . cam, a, and a lever arm in one piece on a shaft, a shoe sliding on the line, and held against the cam face by the rod, to find the position of the face of the shoe against the cam, . a full stroke, method of drawing or marking out, - . designed to cut off steam at five-eighths of the piston stroke, - . heart, to draw, , . object of using, instead of eccentric, . cam wrist plate, and cut-off mechanism, . cams, cut-off, employed instead of eccentrics on steamboats, examples in drawing, . finding the essential points of drawings of, - . necessary imperfections in the operations of, - . part played by the stroke of the engine in determining the conformation of, . three-fourths and seven-eighths, , . cap nut, to pencil in a, . cast iron, representation of, . representation of by cross-hatching, . centre from which an arc of a circle has been struck, to find, . centre of a circle, . centre punch in which the flat sides run out upon a circle, the edges forming curves, . chamfer circles of bolt heads, - . of franklin institute bolt head, . chord of an arc, . chuck plate with six slots, to draw, . circle, degrees of a, - . pencil and circle pen, use of, , . pens, , . that shall pass through any three given points, to draw, . to divide into six divisions, , . circles, to divide with the triangle, . for bolt heads, to draw, . german instrument for drawing, , . use of the instrument in forming, - . circular arcs, rankine's process for rectifying and subdividing, . circumference, . collar, a representation of, . coloring and shading, points to be observed in, . color, to maintain an even shade of, . colors, mixing, . condenser, independent, . cone, cylinder intersecting a, . connecting rod, , , . drawing representing the motion which a crank imparts to a, , . end, . copper, representation of, . corner where the round stem meets the square under the head, . coupling rod, working drawings of a, . crank, drawing representing the motion which it imparts to a connecting rod, . pin and wheel, . cross-hatching or section lining, - . made to denote material of which the piece is composed, , . may sometimes cause the lines of the drawing to appear crooked to the eye, , . representation by, of a section of a number of pieces one within the other, the central bore being filled with short plugs, , . representation by, of three pieces put together, having slots or keyways through them, , . the diagonal lines in, should not meet the edges of the piece, . cross-head, . cross, use of, to designate a square, , . cube, with a hole passing through it, to draw, , . cupped ring, representation of, . curved outline, representation of, , . curve for tooth face, how to find, . representation of the radius for, . curves and lines, - . of gear teeth, names of, . curves for moulding cutter, to find the, - . of thread, template for drawing, . of wheels, construction, to find, . screw threads, drawing, . templates called, . use of, in practice, . cut-off cams, employed instead of eccentrics on steamboats, examples in drawing, . manner of finding essential points of drawings of, - . necessary imperfections in the operations of, - . part played by the stroke of the engine in determining the conformation of, . cut-off mechanism, . cutting tool for a planing machine, representation of, - . cylinder, . a solid, representation of, , . intersecting a cone, of an engine, - . of an engine, drawing of, . cylindrical body joining another at a right angle, a, . body whose top face, if viewed from one point, would appear as a straight line, or if from another as a circle, . piece of wood, which is to be squared, and each side of which square must be an inch, to find the diameter, . pieces and cubes, representation of, . pieces, representation of, by cross-hatching, , . cylindrical pieces, representation of three, one within the other, by cross-hatching, . pieces that join each other, representation of, . pin line-shaded, representation of, . decagon, a, . degrees of a circle, - . diameter of a cylindrical piece of wood, which is to be squared, and each side of which square must measure an inch, to find, . diamond, a, , . different views, arrangement of, - . dimension figures in mechanical drawing, . dimensions, marking, - . distances, relative from the eye, representation of, by line-shading, . dodecagon, a, . dotted lines, use of, . double eye, or knuckle-joint, pencil lines for, . or knuckle-joint, with an offset, . double thread, . drawing board, , . fastening the drawing to, . size of, . small, advantage of, to student, . drawing for engraver on wood, . gear wheels, - . drawing instruments, - . parts of, . selecting and testing, . drawing paper, - . different qualities, kinds and forms, , . location of on the drawing board, , . drawing the curves for screw threads, . to scale, making a, . drawings for engraving, necessity of conforming to the particular process of, . for engravings by the wax process, , . drawings for photo-engraving, . for the blacksmith, . shading and coloring, - . drilling machine, a boiler, , . eccentric and strap, . to find how much motion it will give to its rod, . edge view of a wheel, to draw, . elevation, . ellipse, dimensions of, how taken and designated, . form of a true, . most correct method of drawing, . the, - . elliptical figure, whose proportion of width to breadth shall remain the same, whatever the length of the major axis, . emery paper, use of on the lining pen, . ennagon, a, , . engine work, examples of, - . engine, working drawings of a horse-power, . engravings by the wax process, drawings for, , . examples for practice, - in bolts, nuts and polygons, - . of engine work, - . of work with nine sides, . feed motion of a niles horizontal tool work boring mill, . five-sided figure, to draw, , . flanks of teeth to trace hypocycloides, for, . foci of an ellipse, . franklin institute or united states standard for heads of bolts and of nuts, basis of, . full stroke cam, method of drawing or marking out a, - . gear, part of, showing the teeth in, the remainder illustrated by circles, . gear teeth, names of the curves and lines of, . gear wheels, drawing, - . various examples for laying out, - . gearing oval, construction of, . general view, . geometrical terms, simple explanation of, . geometry, advantage of to the draughtsman, . governor of an engine, , . guide bolts from one pulley to another, arrangement of idle pulleys to, . heart cam, to draw, , . hexagon, a, , . head, representation of a piece with, . head, to draw the end view of, , , . headed screw, to draw, , . radius across corners, . hexagonal form, representation of, . or hexagon heads of bolts, , . hole, representation of by shade or shadow line, . hollows in connection with round pieces, representations of, - . hypocycloides for the flanks of teeth, to trace, . independent condenser, . india ink, advantages of in drawing, . difference between good and inferior, . good, characteristics of, . india ink, higgins', . mixing, . testing, , . the two forms of, . to be used thick, . use of, . use of on parchment, . ink, applying, to the bow pen, . for drawing, - . instruments, preparation and use of, - . iron planing machine, representation of, . iron, wrought and cast, representation of by cross-hatching, . journal, . journals of shafts, . key, a, drawn in perspective, , . drawing of a, . marking the dimensions of on a drawing, . representation of with a shade line, . knuckle-joint, pencil eye for, . with an offset, . large bow or circle pen, joints of, . lathe centre, representation of, . lathe feed motion, drawing of a part of a, . lead pencils for drawing, . lead, representation of by cross-hatching, . left-hand thread, . lever, a, actuating a plunger in a vertical line, to find how much a given amount of motion of the long arm will actuate the plunger, . and shaft, drawing, , , . arm and cam, in one piece on a shaft, a shoe sliding on the line, and held against the cam face by the rod, to find the position of the face of the shoe against the cam, . example of the end of a, acting directly on a shoe, . to find how much a given amount of motion of a long arm will move the short arm of a lever, . levers, two, upon their axles or shafts, the arms connected by a link, and one arm connected to a rod, . light in shading, . management of, in mechanical drawing, , . line-shaded engravings, drawing for, - . line-shading, - . and drawing for line-shaded engravings, - . in perspective drawing of a pipe-threading stock and die, . mechanical drawing made to look better and show more distinctly by, . simplest form of, . lines and curves, - . lines in pencilling, where to begin, , . lining pen, . lining pen, form of, - . lining pen, use of with a t square, , . link introduced in the place of a roller, to find the amount of motion of the rod, . quick return, plotting out the motion of a shaper, - . links, pencilling for, , . locomotive frame, . spring, . machine screw, to draw, , . main journal, . marking dimensions, - . measuring rules, draughtsman's, . mechanical motions, plotting, - . motion an eccentric will give to its rod, to find, . a shaper link, quick return, plotting out, - . imparted in a straight line to a rod, attached to an eccentric strap, to find the amount of, - . which a crank imparts to a connecting rod, , . motions, plotting mechanical, - . moulding cutter, finding the curves for, - . niles' horizontal tool work boring mill, feed motion of a, . nonagon, a, . nut, a representation of the shade line on, . cap, to pencil in a, . to show the thread depth in the top or end view of a, . nuts' and bolts, dimensions of united states standard, . nuts and polygons, examples in, - . octagon, a, , . oil cup, representation of, , . outline views, , . oval gearing, construction of, . paper cutter, the form of the end of, . rules or scales, . parabola, to draw by lines, , . to draw mechanically, , . parallel lines, . parallelogram, , . parchment, use of india ink on, . pen, german, regulated to draw lines of various breadths, , . lining, form of, - . pen point, forming the, , . form of recently introduced, . pen points, oil-stoning, . pen, with sapphire points, . pens, circle, , . used in drawing, . pencil holders for sticks of lead, . lines in drawing, . sharpening for fine work, . pencilling for a link, having the hubs on one side only, . in a cap nut, . penknife and rubber scratching out, . pentagon, a, , . perimeter, the, . periphery, . perpendicular line, . perspective sketches to denote the shape of the piece, . photo-engraving, drawings for, , . piece of work should, in mechanical drawing, be presented in as few views as possible, . pillow block box, . pin, in a socket, in section, representation of, , . pinion teeth, to draw to the pitch of the inner and small end of, . pins and discs, discrimination of, in mechanical drawing, . pipe threading stock and die, drawing of, . pitch circle of the inner and small end of, to draw, . to obtain a division of the lines that divide, . plan, . planing machine, a cutting tool for, - . plotting mechanical motions, - . out the motion of a shaper link quick return, - . point, a, . points of drawing instruments, . polished surfaces, to show by shading, . polygon of twelve equal sides, to draw, , . polygons, bolts and nuts, examples of, - . construction of, . designation of the angles of, . names of regular, , . scales giving the lengths of the sides of, . preparation and use of the instruments, - . produced line, . projecting one view from another, . projections, - . protractors, . pulley, medart, shading a, . pulleys, arrangement of idle, to guide bolts from one pulley to another, . quadrangle, quadrilateral or tetragon, . quadrant of a circle, . quick return motion, whitworth, plotting out, - . radius across corners of a hexagon, . rankine's process for rectifying and subdividing circular arcs, . reducing scales, . rectangle, a, , . rectangular piece, a, to draw in two views, , . requires two or three views, , . representation of, . red ink, marking dimensions of mechanical drawings in, . rhomboid, a, . rhomb, rhombus or diamond, , . right line, a, . ring with a hexagon cross section, . rivet, side and end views of, . roller, example of a short arm having a, acting upon a larger roller, . rod, attached to an eccentric strap, to find the amount of motion imparted in a straight line to a, - . end with a round stem, . round stem, a representation of, . top and bottom thread, . rubber, . form of, . proper uses of, . sponge, . the use of, . to be used on bristol board, . velvet, . rule, steel, . sapphire points, pen with, . scale for diameter of a regular polygon, . of tooth proportions, . triangular, . scales, for measurement and drawing, . reducing, . scratching out, . screw machine, to draw, , . thread, united states standard, to draw, - . threads and spirals, - . threads, drawing the curves for, . threads for small bolts, with the angles of the threads drawn in, - . threads of a large diameter, . section lining or cross-hatching, - . sectional view of a section of a wheel, for showing dimensions through arms and hub, . sector of a circle, . segment of a circle, . semicircle, . shade curve, representation of, . line produced for circles, . shade line, produced in straight lines, . or shadow line, . shading a medart pulley, . and coloring, points to be observed in, . brush, . by means of lines to distinguish round from flat surfaces, and denote relative distances of surfaces, . example in, of a blake's patent direct acting steam pump, , . example of, in an independent condenser, . light in, . simple, . to show by, that the surfaces are highly polished, . shadow line, . lines and line shading, - . shaft for cam plate, . shaper link, quick return, plotting out the motion of a, - . shoe against a cam, to find the position of the face of, . side elevation, drawing a, . sides or flats of work, to find the lengths of, , . slots not radiating from a centre, to draw, , . radiating from a centre, . spiral spring, to draw, . spiral wound round a cylinder, whose end is cut off at an angle, . spirals and screw threads, - . sponge, rubber, . spring bow pencil, for circles, . pen, for circles, , . spring, spiral, to draw, . spur wheel teeth, how to draw, . square, a, , . body, which measures one inch on each side, to find what it measures across the corners, . square part, a representation of, . parts, use of a cross to designate, , . thread, to draw a, - . steam boiler, horizontal, for stationary engine, . chest and valves, . chest side, and horizontal cross section of cylinder, . pump, blake's patent direct acting, , . steel, representation of, . representation of by cross-hatching, . square, improved, with pivoted blade, . steps, to draw a piece containing, - . stock and die, pipe-threading, drawing of, . straight line in geometry termed a right line, . or lining pen, use of with a t square, , . stud, to draw a, . stuffing-box and gland, . surface of the paper, condensing after rubbing out, . surfaces, highly polished, to show by shading, . tacks for drawing paper, , . tangent, . taper or conical hole, to denote in drawing, . sides in a drawing, , . tees, . teeth of wheels, rules for drawing, . pinion, to draw the pitch of the inner and small end of, . spur wheel, how to draw, . to trace hypocycloides for the flanks of, . template for drawing the curves of thread, . templates called curves, . t square, , . t squares, different kinds of, . tetragon, a, , , . thread, a double, . a round top and bottom, . depth in the top or end view of a nut, to show, . left hand, . square, to draw a, - . whitworth, . threads of a large diameter, . thumb tacks for drawing paper, . tint, to graduate the depth of, for a cylindrical surface, . tooth face, how to find the curve for, . proportions, willis' scale of, . tracing cloth, . paper, . trammel, use of in drawing an ellipse, . trapezium, . trapezoid, a, . triangle, equilateral, , . isosceles, , . obtuse, . right angle, . scalene, . use of in dividing circles, . use of in drawing polygons, , . use of to draw slots radiating from a centre, . triangles, - , - . requirements in use of, , . to draw, . using with the square, . triangular scale, . trigon, a, , . true ellipse, a near approach to the form of, - . united states standard bolts and nuts, - . standard thread, to draw, , . valve of an engine, - . valves, . vertex, the, . views, different arrangement of, - . of a piece of work, designations of, , . of a piece, two systems of placing, - . washer, a, representation of the shadow side of, . wax process, drawings for engravings by, , . engraving from a print from a wood engraving, . wedge-shaped piece, representation of a, . wheel, edge view of a, to draw, . sectional view of a section of a, . wheels, construction, to find the curves of, . to draw the arcs for the teeth of, . whitworth thread, . quick return motion, plotting out, - . willis' scale of tooth proportions, . application of, . wood engraving, drawing for, . wood, representation of by cross-hatching, . representation of, regular and irregular shade lines in, . wrought iron, representation of, . representation of by cross-hatching, . catalogue of practical and scientific books published by henry carey baird & co. industrial publishers, booksellers and importers, walnut street, philadelphia. [illustration: pointing finger] any of the books comprised in this catalogue will be sent by mail, free of postage, to any address in the world, at the publication prices. [illustration: pointing finger] a descriptive catalogue, pages, vo., will be sent free and free of postage, to any one in any part of the world, who will furnish his address. [illustration: pointing finger] where not otherwise stated, all of the books in this catalogue are bound in muslin. $amateur mechanics' workshop:$ a treatise containing plain and concise directions for the manipulation of wood and metals, including casting, forging, brazing, soldering and carpentry. by the author of the "lathe and its uses." third edition. illustrated. vo. $ . $andres.--a practical treatise on the fabrication of volatile and fat varnishes, lacquers, siccatives and sealing waxes.$ from the german of erwin andres, manufacturer of varnishes and lacquers. with additions on the manufacture and application of varnishes, stains for wood, horn, ivory, bone and leather. from the german of dr. emil winckler and louis e. andes. the whole translated and edited by william t. brannt. with illustrations. mo. $ . $arlot.--a complete guide for coach painters:$ translated from the french of m. arlot, coach painter; for eleven years foreman of painting to m. eherler, coach maker, paris. by a.a. fesquet, chemist and engineer. to which is added an appendix, containing information respecting the materials and the practice of coach and car painting and varnishing in the united states and great britain. mo. $ . $armengaud, amoroux, and johnson.--the practical draughtsman's book of industrial design, and machinist's and engineer's drawing companion$: forming a complete course of mechanical engineering and architectural drawing. from the french of m. armengaud the elder, prof. of design in the conservatoire of arts and industry, paris, and mm. armengaud the younger, and amoroux, civil engineers. rewritten and arranged with additional matter and plates, selections from and examples of the most useful and generally employed mechanism of the day. by william johnson, assoc. inst. c.e. illustrated by fifty folio steel plates, and fifty wood-cuts. a new edition, to., half morocco $ . $armstrong.--the construction and management of steam boilers$: by r. armstrong, with an appendix by robert mallet, c.f., f.r.s. seventh edition. illustrated. vol. mo. $ . $arrowsmith.--paper-hanger's companion$: a treatise in which the practical operations of the trade are systematically laid down: with copious directions preparatory to papering; preventives against the effect of damp on walls; the various cements and pastes adapted to the several purposes of the trade; observations and directions for the panelling and ornamenting of rooms, etc. by james arrowsmith. mo., cloth $ . $ashton.--the theory and practice of the art of designing fancy cotton and woollen cloths from sample$: giving full instructions for reducing drafts, as well as the methods of spooling and making out harness for cross drafts and finding any required reed; with calculations and tables of yarn. by frederic t. ashton, designer, west pittsfield, mass. with fifty-two illustrations. one vol. folio $ . $auerbach--crookes.--anthracen$: its constitution, properties, manufacture and derivatives, including artificial alizarin, anthrapurpurin, etc., with their applications in dyeing and printing. by g. auerbach. translated and edited from the revised manuscript of the author, by wm. crookes, f.r. s., vice-president of the chemical society. vo. $ . $baird.--miscellaneous papers on economic questions. by henry carey baird.$ (_in preparation._) $baird.--the american cotton spinner, and manager's and carder's guide$: a practical treatise on cotton spinning; giving the dimensions and speed of machinery, draught and twist calculations, etc.; with notices of recent improvements: together with rules and examples for making changes in the sizes and numbers of roving and yarn. compiled from the papers of the late robert h. baird. mo. $ . $baird.--standard wages computing tables:$ an improvement in all former methods of computation, so arranged that wages for days, hours, or fractions of hours, at a specified rate per day or hour, may be ascertained at a glance. by t. spangler baird. oblong folio $ . $baker.--long-span railway bridges:$ composing investigations of the comparative theoretical and practical advantages of the various adopted or proposed type systems of construction; with numerous formulæ and tables. by b. baker. mo. $ . $baker.--the mathematical theory of the steam-engine:$ with rules at length, and examples worked out for the use of practical men. by t. baker, c.e., with numerous diagrams. sixth edition, revised by prof. j.r. young. mo. $ . $barlow.--the history and principles of weaving, by hand and by power:$ reprinted, with considerable additions, from "engineering," with a chapter on lace-making machinery, reprinted from the journal of the "society of arts." by alfred barlow. with several hundred illustrations. vo., pages $ . $barr.--a practical treatise on the combustion of coal:$ including descriptions of various mechanical devices for the economic generation of heat by the combustion of fuel, whether solid, liquid or gaseous. vo. $ . $barr.--a practical treatise on high pressure steam boilers:$ including results of recent experimental tests of boiler materials, together with a description of approved safety apparatus, steam pumps, injectors and economizers in actual use. by wm. m. barr. illustrations. vo. $ . $bauerman.--a treatise on the metallurgy of iron:$ containing outlines of the history of iron manufacture, methods of assay, and analysis of iron ores, processes of manufacture of iron and steel, etc., etc. by h. bauerman, f.g.s., associate of the royal school of mines. fifth edition, revised and enlarged. illustrated with numerous wood engravings from drawings by j.b. jordan. mo. . $bayles.--house drainage and water service:$ in cities, villages and rural neighborhoods. with incidental consideration of certain causes affecting the healthfulness of dwellings. by james c. bayles, editor of "the iron age" and "the metal worker." with numerous illustrations. vo. cloth, $ . $beans.--a treatise on railway curves and location of railroads:$ by e.w. beans, c.e. illustrated. mo. tucks $ . $beckett.--a rudimentary treatise on clocks, and watches and bells:$ by sir edmund beckett, bart., ll. d., q.c.f.r.a.s. with numerous illustrations. seventh edition, revised and enlarged. mo. $ . $bell.--carpentry made easy$: or, the science and art of framing on a new and improved system with specific instructions for building balloon frames, barn frames, mill; frames, warehouses, church spires, etc. comprising also a system of bridge building, with bills, estimates of cost, and valuable tables. illustrated by forty four plates, comprising nearly figures. by william e. bell, architect and practical builder. vo. $ . $bemrose.--fret-cutting and perforated carving.$ with fifty three practical illustrations by w. bemrose, jr. vol. quarto. $ . $bemrose.--manual of buhl-work and marquetry.$ with practical instructions for learners, and ninety colored designs by w. bemrose, jr. vol. quarto. $ . $bemrose.--manual of wood carving.$ with practical illustrations for learners of the art, and original and selected designs. by william bemrose, jr. with an introduction by llewellyn jewitt, f.s.a., etc. with illustrations, to. $ . $billings.--tobacco$ its history, variety, culture, manufacture, commerce, and various modes of use. by e.r. billings. illustrated by nearly engravings. vo. $ . $bird.--the american practical dyers' companion.$ comprising a description of the principal dye stuffs and chemicals used in dyeing, their natures and uses, mordants, and how made, with the best american, english, french and german processes for bleaching and dyeing silk, wool, cotton, linen, flannel, felt, dress goods, mixed and hosiery yarns, feathers, grass, felt, fur, wool, and straw hats, jute yarn, vegetable ivory, mats, skins, furs, leather, etc., etc. by wood, aniline, and other processes, together with remarks on finishing agents, and instructions in the finishing of fabrics, substitutes for indigo, water proofing of materials, tests and purification of water, manufacture of aniline and other new dye wares, harmonizing colors, etc., etc., embracing in all over receipts for colors and shades, _accompanied by dyed samples of raw materials and fabrics_ by f.j. bird, practical dyer, author of "the dyers' hand book." vo. $ . $blinn.--a practical workshop companion for tin, sheet-iron, and copper-plate workers.$ containing rules for describing various kinds of patterns used by tin, sheet iron, and copper plate workers, practical geometry; mensuration of surfaces and solids, tables of the weights of metals, lead pipe, etc., tables of areas and circumferences of circles, japan, varnishes, lackers, cements, compositions, etc., etc. by leroy j. blinn, master mechanic. with over one hundred illustrations. mo. $ . $booth.--marble worker's manual.$ containing practical information respecting marbles in general, their cutting, working and polishing, veneering of marble, mosaics, composition and use of artificial marble, stuccos, cements, receipts. secrets, etc., etc. translated from the french by m.l. booth. with an appendix concerning american marbles. mo, cloth $ . $booth and morfit.--the encyclopædia of chemistry, practical and theoretical.$ embracing its application to the arts, metallurgy, mineralogy, geology, medicine and pharmacy. by james c. booth, melter and refiner in the united states mint, professor of applied chemistry in the franklin institute, etc., assisted by campbell morfit, author of "chemical manipulations," etc. seventh edition. complete in one volume. royal vo., pages, with numerous wood cuts and other illustrations. $ . $bramwell.--the wool carder's vade-mecum$. a complete manual of the art of carding textile fabrics. by w.c. bramwell. third edition, revised and enlarged. illustrated pp. . mo. $ . $brannt.--a practical treatise on the raw materials and the distillation and rectification of alcohol, and the preparation of alcoholic liquors, liqueurs, cordials, bitters, etc.$: edited chiefly from the german of dr. k. stammer, dr. f. elsner, and e. schubert. by wm t. brannt. illustrated by thirty one engravings. mo. $ . $brannt--wahl.--the techno-chemical receipt book.$ containing several thousand receipts covering the latest, most important, and most useful discoveries in chemical technology, and their practical application in the arts, and the industries. edited chiefly from the german of drs. winckler, elsner, heintze, mierzinski, jacobsen, koller and heinzerling with additions by wm.t. brannt and wm.h. wahl, ph. d. illustrated by engravings. mo. pages. $ . $brown.--five hundred and seven mechanical movements.$ embracing all those which are most important in dynamics, hydraulics, hydrostatics, pneumatics, steam engines, mill and other gearing, presses, horology and miscellaneous machinery, and including many movements never before published, and several of which have only recently come into use. by henry t. brown. mo. $ . $buckmaster.--the elements of mechanical physics.$ by j.c. buckmaster. illustrated with numerous engravings. mo. $ . $bullock.--the american cottage builder.$ a series of designs, plans and specifications, from $ to $ , , for homes for the people, together with warming, ventilation, drainage, painting and landscape gardening. by john bullock, architect and editor of "the rudiments of architecture and building," etc., etc. illustrated by engravings. vo. $ . $bullock.--the rudiments of architecture and building.$ for the use of architects, builders, draughtsmen, machinists, engineers and mechanics. edited by john bullock author of "the american cottage builder." illustrated by engravings. vo. $ . $burgh.--practical rules for the proportions of modern engines and boilers for land and marine purposes.$ by n.p. burgh, engineer. mo. $ . $burns.--the american woolen manufacturer$: a practical treatise on the manufacture of woolens, in two parts. part first gives full and explicit instructions upon drafting, cross-drawing, combining weaves, and the correct arrangement of weights, colors and sizes of yarns to produce any desired fabric. illustrated with diagrams of various weavings, and twelve samples of cloth for explanation and practice. part second is fully supplied with extended tables, rules, examples, explanations, etc.; gives full and practical information, in detailed order, from the stock department to the market, of the proper selection and use of the various grades and staples of wool, with the admixture of waste, cotton and shoddy; and the proper application and economical use of the various oils, drugs, dye stuffs, soaps, belting, etc. also, the most approved method for calculating and estimating the cost of goods, for all wool, wool waste and cotton and cotton warps. with examples and calculations on the circular motions of wheels, pinions, drums, pulleys and gears, how to speed them, etc. the two parts combined form a whole work on the american way of manufacturing more complete than any yet issued. by george c. burns. vo. $byles.--sophisms of free trade and popular political economy examined.$ by a barrister (sir john barnard byles, judge of common pleas). from the ninth english edition, as published by the manchester reciprocity association. mo. $ . $bowman.--the structure of the wool fibre in its relation to the use of wool for technical purposes$: being the substance, with additions, of five lectures, delivered at the request of the council, to the members of the bradford technical college, and the society of dyers and colorists. by f.h. bowman, d. sc., f.r.s.e., f.l.s. illustrated by engravings. vo. $ . $byrn.--the complete practical distiller:$ comprising the most perfect and exact theoretical and practical description of the art of distillation and rectification; including all of the most recent improvements in distilling apparatus; instructions for preparing spirits from the numerous vegetables, fruits, etc; directions for the distillation and preparation of all kinds of brandies and other spirits, spirituous and other compounds, etc. by m. la fayette byrn, m.d. eighth edition. to which are added practical directions for distilling, from the french of th. fling, brewer and distiller. mo. $byrne.--hand-book for the artisan, mechanic, and engineer$: comprising the grinding and sharpening of cutting tools, abrasive processes, lapidary work, gem and glass engraving, varnishing and lackering, apparatus, materials and processes for grinding and polishing, etc. by oliver byrne. illustrated by wood engravings. vo. $ . $byrne.--pocket-book for railroad and civil engineers$: containing new, exact and concise methods for laying out railroad curves, switches, frog angles and crossings; the staking out of work; levelling; the calculation of cuttings; embankments; earthwork, etc. by oliver byrne. mo., full bound, pocket-book form. $ . $byrne.--the practical metal-worker's assistant$: comprising metallurgic chemistry; the arts of working all metals and alloys; forging of iron and steel; hardening and tempering; melting and mixing; casting and founding; works in sheet metal; the processes dependent on the ductility of the metals; soldering; and the most improved processes and tools employed by metal-workers. with the application of the art of electro-metallurgy to manufacturing processes; collected from original sources, and from the works of holtzapffel, bergeron, leupold, plumier, napier, scoffern, clay, fairbairn and others. by oliver byrne. a new, revised and improved edition, to which is added an appendix, containing the manufacture of russian sheet-iron. by john percy, m.d., f.r.s. the manufacture of malleable iron castings, and improvements in bessemer steel. by a.a. fesquet, chemist and engineer. with over six hundred engravings, illustrating every branch of the subject. vo. $ . $byrne.--the practical model calculator$: for the engineer, mechanic, manufacturer of engine work, naval architect, miner and millwright. by oliver byrne. vo., nearly pages. $ . $cabinet maker's album of furniture$: comprising a collection of designs for various styles of furniture. illustrated by forty-eight large and beautifully engraved plates. oblong, vo. $ . $callingham.--sign writing and glass embossing$: a complete practical illustrated manual of the art. by james callingham. mo. $ . $campin.--a practical treatise on mechanical engineering$: comprising metallurgy, moulding, casting, forging, tools, workshop machinery, mechanical manipulation, manufacture of steam-engines, etc. with an appendix on the analysis of iron and iron ores. by francis campin, c.e. to which are added, observations on the construction of steam boilers, and remarks upon furnaces used for smoke prevention; with a chapter on explosions. by r. armstrong, c.e., and john bourne. rules for calculating the change wheels for screws on a turning lathe, and for a wheel-cutting machine. by j. la nicca. management of steel, including forging, hardening, tempering, annealing, shrinking and expansion; and the case-hardening of iron. by g. ede. vo. illustrated with twenty-nine plates and wood engravings. $ . $carey.--a memoir of henry c. carey.$ by dr. wm. elder. with a portrait. vo., cloth $. $carey.--the works of henry c. carey:$ $harmony of interests:$ agricultural, manufacturing and commercial. vo. $ . $manual of social science.$ condensed from carey's "principles of social science." by kate mckean. vol. mo. $ . $miscellaneous works.$ with a portrait. vols. vo. $ . $past, present and future.$ vo. $ . $principles of social science.$ volumes, vo. $ . $the slave-trade, domestic and foreign;$ why it exists, and how it may be extinguished ( ). vo. $ . $the unity of law:$ as exhibited in the relations of physical, social, mental and moral science ( ). vo. $ . $clark.--tramways, their construction and working$: embracing a comprehensive history of the system. with an exhaustive analysis of the various modes of traction, including horse-power, steam, heated water and compressed air; a description of the varieties of rolling stock, and ample details of cost and working expenses. by d. kinnear clark. illustrated by over wood engravings, and thirteen folding plates. vols. vo. $ . $colburn.--the locomotive engine$: including a description of its structure, rules for estimating its capabilities, and practical observations on its construction and management. by zerah colburn. illustrated. mo. $ . $collens.--the eden of labor; or, the christian utopia.$ by t. wharton collens, author of "humanics," "the history of charity," etc. mo. paper cover, $ . ; cloth $ . $cooley.--a complete practical treatise on perfumery$: being a hand-book of perfumes, cosmetics and other toilet articles. with a comprehensive collection of formulæ. by arnold j. cooley. mo. $ . $cooper.--a treatise on the use of belting for the transmission of power.$ with numerous illustrations of approved and actual methods of arranging main driving and quarter twist belts, and of belt fastenings. examples and rules in great number for exhibiting and calculating the size and driving power of belts. plain, particular and practical directions for the treatment, care and management of belts. descriptions of many varieties of beltings, together with chapters on the transmission of power by ropes; by iron and wood frictional gearing; on the strength of belting leather; and on the experimental investigations of morin, briggs, and others. by john h. cooper, m.e. vo. $ . $craik.--the practical american millwright and miller.$ by david craik, millwright. illustrated by numerous wood engravings and two folding plates. vo. $ . $cristiani.--a technical treatise on soap and candles$: with a glance at the industry of fats and oils. by r.s. cristiani, chemist. author of "perfumery and kindred arts." illustrated by engravings. pages, vo. $ . $cristiani.--perfumery and kindred arts$: a comprehensive treatise on perfumery, containing a history of perfumes from the remotest ages to the present time. a complete detailed description of the various materials and apparatus used in the perfumer's art, with thorough practical instruction and careful formulæ, and advice for the fabrication of all known preparations of the day, including essences, tinctures, extracts, spirits, waters, vinegars, pomades, powders, paints, oils, emulsions, cosmetics, infusions, pastilles, tooth powders and washes, cachous, hair dyes, sachets, essential oils, flavoring extracts, etc.; and full details for making and manipulating fancy toilet soaps, shaving creams, etc., by new and improved methods. with an appendix giving hints and advice for making and fermenting domestic wines, cordials, liquors, candies, jellies, syrups, colors, etc., and for perfuming and flavoring segars, snuff and tobacco, and miscellaneous receipts for various useful analogous articles. by r.s. cristiani, consulting chemist and perfumer, philadelphia. vo. $ . $cupper.--the universal stair-builder$: being a new treatise on the construction of stair-cases and hand-rails; showing plans of the various forms of stairs, method of placing the risers in the cylinders, general method of describing the face moulds for a hand-rail, and an expeditious method of squaring the rail. useful also to stonemasons constructing stone stairs and hand-rails; with a new method of sawing the twist part of any hand-rail square from the face of the plank, and to a parallel width. also, a new method of forming the easings of the rail by a gauge; preceded by some necessary problems in practical geometry, with the sections of prismatic solids. illustrated by plates. by r.a. cupper, architect, author of "the practical stair-builder's guide." third edition. large to. $davidson.--a practical manual of house painting, graining, marbling, and sign-writing$: containing full information on the processes of house painting in oil and distemper, the formation of letters and practice of sign-writing, the principles of decorative art, a course of elementary drawing for house painters, writers, etc., and a collection of useful receipts. with nine colored illustrations of woods and marbles, and numerous wood engravings. by ellis a. davidson. mo. $ . $davies.--a treatise on earthy and other minerals and mining$: by d.c. davies, f.g.s., mining engineer, etc. illustrated by engravings. mo. $ . $davies.--a treatise on metalliferous minerals and mining$: by d.c. davies, f.g.s., mining engineer, examiner of mines, quarries and collieries. illustrated by engravings of geological formations, mining operations and machinery, drawn from the practice of all parts of the world. d edition, mo., pages. $ . $davies.--a treatise on slate and slate quarrying$: scientific, practical and commercial. by d.c. davies, f.g.s., mining engineer, etc. with numerous illustrations and folding plates. mo. $ . $davis.--a practical treatise on the manufacture of bricks, tiles, terra-cotta, etc.$: including common, pressed, ornamentally shaped, and enamelled bricks, drain-tiles, straight and curved sewer-pipes, fire-clays, fire-bricks, terra-cotta, roofing-tiles, flooring-tiles, art-tiles, mosaic plates, and imitation of intarsia or inlaid surfaces; comprising every important product of clay employed in architecture, engineering, the blast-furnace, for retorts, etc., with a history and the actual processes in handling, disintegrating, tempering, and moulding the clay into shape, drying naturally and artificially, setting and burning, enamelling in polychrome colors, composition and application of glazes, etc.; including full detailed descriptions of the most modern machines, tools, kilns, and kiln-roofs used. by charles thomas davis. illustrated by engravings and plates. vo., pages $ . $davis.--the manufacture of leather$: being a description of all of the processes for the tanning, tawing, currying, finishing and dyeing of every kind of leather; including the various raw materials and the methods for determining their values; the tools, machines, and all details of importance connected with an intelligent and profitable prosecution of the art, with special reference to the best american practice. to which are added complete lists of all american patents for materials, processes, tools, and machines for tanning, currying, etc. by charles thomas davis. illustrated by engravings and samples of dyed leathers. one vol., vo., pages $ . $dawidowsky--brannt.--a practical treatise on the raw materials and fabrication of glue, gelatine, gelatine veneers and foils, isinglass, cements, pastes, mucilages, etc.$: based upon actual experience. by f. dawidowsky, technical chemist. translated from the german, with extensive additions, including a description of the most recent american processes, by william t. brannt, graduate of the royal agricultural college of eldena, prussia. engravings. mo. $ . $de graff.--the geometrical stair-builders' guide$: being a plain practical system of hand-railing, embracing all its necessary details, and geometrically illustrated by twenty-two steel engravings; together with the use of the most approved principles of practical geometry. by simon de graff, architect. to. $ . $de koninck--dietz.--a practical manual of chemical analysis and assaying:$ as applied to the manufacture of iron from its ores, and to cast iron, wrought iron, and steel, as found in commerce. by l.l. de koninck, dr. sc, and e. dietz, engineer. edited with notes, by robert mallet, f.r.s., f.s.g., m.i.c.e., etc. american edition, edited with notes and an appendix on iron ores, by a.a. fesquet, chemist and engineer. mo. $ . $duncan.--practical surveyor's guide:$ containing the necessary information to make any person of common capacity, a finished land surveyor without the aid of a teacher. by andrew duncan. illustrated. mo. $ . $duplais--a treatise on the manufacture and distillation of alcoholic liquors:$ comprising accurate and complete details in regard to alcohol from wine, molasses, beets, grain, rice, potatoes, sorghum, asphodel, fruits, etc.; with the distillation and rectification of brandy, whiskey, rum, gin, swiss absinthe, etc., the preparation of aromatic waters. volatile oils or essences, sugars, syrups, aromatic tinctures, liqueurs, cordial wines, effervescing wines, etc., the ageing of brandy and the improvement of spirits, with copious directions and tables for testing and reducing spirituous liquors, etc., etc. translated and edited from the french of mm. duplais, ainè et jeune. by m. mckennie, m.d. to which are added the united states internal revenue regulations for the assessment and collection of taxes on distilled spirits. illustrated by fourteen folding plates and several wood engravings. pp. vo. $ . $dussauce.--a general treatise on the manufacture of vinegar:$ theoretical and practical. comprising the various methods, by the slow and the quick processes, with alcohol, wine, grain, malt, cider, molasses, and beets; as well as the fabrication of wood vinegar, etc., etc. by prof. h. dussauce. vo. $ . $dussauce.--practical treatise on the fabrication of matches, gun cotton, and fulminating powder.$ by professor h. dussauce. mo. $ . $dyer and color-maker's companion:$ containing upwards of two hundred receipts for making colors, on the most approved principles, for all the various styles and fabrics now in existence; with the scouring process, and plain directions for preparing, washing-off, and finishing the goods. mo. $ . $edwards.--a catechism of the marine steam-engine,$ for the use of engineers, firemen, and mechanics. a practical work for practical men. by emory edwards, mechanical engineer. illustrated by sixty-three engravings, including examples of the most modern engines. third edition, thoroughly revised, with much additional matter. mo. pages $ . $edwards.--modern american locomotive engines,$ their design, construction and management. by emory edwards. illustrated mo. $ . $edwards.--modern american marine engines, boilers, and screw propellers$, their design and construction. showing the present practice of the most eminent engineers and marine engine builders in the united states. illustrated by large and elaborate plates. to. $ . $edwards.--the practical steam engineer's guide$ in the design, construction, and management of american stationary, portable, and steam fire engines, steam pumps, boilers, injectors, governors, indicators, pistons and rings, safety valves and steam gauges. for the use of engineers, firemen, and steam users. by emory edwards. illustrated by engravings. pages. mo. $ . $elder.--conversations on the principal subjects of political economy.$ by dr. william elder. vo. $ . $elder.--questions of the day$, economic and social. by dr. william elder. vo. $ . $elder.--memoir of henry c. carey.$ by dr. william elder. vo. cloth. $. $erni.--mineralogy simplified.$ easy methods of determining and classifying minerals, including ores, by means of the blowpipe, and by humid chemical analysis, based on professor von kobell's tables for the determination of minerals, with an introduction to modern chemistry. by henry erni, a.m., m.d., professor of chemistry. second edition, rewritten, enlarged and improved. mo. $ . $fairbairn.--the principles of mechanism and machinery of transmission$ comprising the principles of mechanism, wheels, and pulleys, strength and proportions of shafts, coupling of shafts, and engaging and disengaging gear. by sir william fairbairn, bait. c.e. beautifully illustrated by over wood-cuts. in one volume, mo. $ . $fitch.--bessemer steel$, ores and methods, new facts and statistics relating to the types of machinery in use, the methods in vogue, cost and class of labor employed, and the character and availability of the ores utilized in the manufacture of bessemer steel in europe and in the united states; together with opinions and excerpts from various accepted authorities. compiled and arranged by thomas w. fitch. vo. $ . $fleming.--narrow gauge railways in america.$ a sketch of their rise, progress, and success. valuable statistics as to grades, curves, weight of rail, locomotives, cars, etc. by howard fleming. illustrated, vo. $ . $forsyth.--book of designs for headstones, mural, and other monuments$: containing designs. by james forsyth. with an introduction by charles boutell, m.a. to., cloth $ . $frankel--hutter.--a practical treatise on the manufacture of starch, glucose, starch-sugar, and dextrine:$ based on the german of ladislaus von wagner, professor in the royal technical high school, buda-pest, hungary, and other authorities. by julius frankel, graduate of the polytechnic school of hanover. edited by robert hutter, chemist, practical manufacturer of starch-sugar. illustrated by engravings, covering every branch of the subject, including examples of the most recent and best american machinery. vo., pp. $ . $gee.--the goldsmith's handbook:$ containing full instructions for the alloying and working of gold, including the art of alloying, melting, reducing, coloring, collecting, and refining; the processes of manipulation, recovery of waste; chemical and physical properties of gold; with a new system of mixing its alloys; solders, enamels, and other useful rules and recipes. by george e. gee. mo. $ . $gee.--the silversmith's handbook:$ containing full instructions for the alloying and working of silver, including the different modes of refining and melting the metal; its solders; the preparation of imitation alloys; methods of manipulation; prevention of waste; instructions for improving and finishing the surface of the work; together with other useful information and memoranda. by george e. gee, jeweller. illustrated. mo. $ . $gothic album for cabinet-makers:$ designs for gothic furniture. twenty-three plates. oblong $ . $greenwood.--steel and iron:$ comprising the practice and theory of the several methods pursued in their manufacture, and of their treatment in the rolling-mills, the forge, and the foundry. by william henry greenwood, f.c.s. asso. m.i.c.e., m.i.m.e., associate of the royal school of mines. with diagrams, pages. mo. $ . $gregory.--mathematics for practical men:$ adapted to the pursuits of surveyors, architects, mechanics, and civil engineers. by olinthus gregory. vo., plates. $ . $grier.--rural hydraulics:$ a practical treatise on rural household water supply. giving a full description of springs and wells, of pumps and hydraulic ram, with instructions in cistern building, laying of pipes, etc. by w.w. grier. illustrated vo. $. $grimshaw.--modern milling:$ being the substance of two addresses delivered by request, at the franklin institute, philadelphia, january th; and january th, . by robert grimshaw, ph. d. edited from the phonographic reports. with illustrations. vo. $ . $grimshaw.--saws:$ the history, development, action, classification, and comparison of saws of all kinds. _with copious appendices._ giving the details of manufacture, filing. setting, gumming, etc. care and use of saws; tables of gauges; capacities of saw-mills; list of saw-patents, and other valuable information. by robert grimshaw. second and greatly enlarged edition, _with supplement_, and illustrations. quarto $ . $grimshaw.--a supplement to grimshaw on saws$: containing additional practical matter, more especially relating to the forms of saw-teeth, for special material and conditions, and to the behavior of saws under particular conditions. illustrations. by robert grimshaw. quarto. $ . $griswold.--railroad engineer's pocket companion for the field$: comprising rules for calculating deflection distances and angles, tangential distances and angles, and all necessary tables for engineers; also the art of levelling from preliminary survey to the construction of railroads, intended expressly for the young engineer, together with numerous valuable rules and examples. by w. griswold. mo., tucks $ . $gruner.--studies of blast furnace phenomena$: by m.l. gruner, president of the general council of mines of france, and lately professor of metallurgy at the ecole des mines. translated, with the author's sanction, with an appendix, by l.d. b. gordon, f.r.s.e., f.g.s. vo. $ . $guettier.--metallic alloys$: being a practical guide to their chemical and physical properties, their preparation, composition, and uses. translated from the french of a. guettier, engineer and director of founderies, author of "la fouderie en france," etc., etc. by a.a. fesquet, chemist and engineer. mo. $ . $haserick.--the secrets of the art of dyeing wool, cotton, and linen$, including bleaching and coloring wool and cotton hosiery and random yarns. a treatise based on economy and practice. by e.c. haserick. _illustrated by dyed patterns of the yarns or fabrics._ vo. $ . $hats and felting$: a practical treatise on their manufacture. by a practical hatter. illustrated by drawings of machinery, etc. vo. $ . $henry.--the early and later history of petroleum$: with authentic facts in regard to its development in western pennsylvania. with sketches of the pioneer and prominent operators, together with the refining capacity of the united states. by j.t. henry. illustrated vo. $hoffer.--a practical treatise on caoutchouc and gutta percha$, comprising the properties of the raw materials, and the manner of mixing and working them; with the fabrication of vulcanized and hard rubbers, caoutchouc and gutta percha compositions, water-proof substances, elastic tissues, the utilization of waste, etc., etc. from the german of raimund hoffer. by w.t. brannt. illustrated mo. $ . $hofmann.--a practical treatise on the manufacture of paper in all its branches$: by carl hofmann, late superintendent of paper-mills in germany and the united states; recently manager of the "public ledger" paper mills, near elkton, maryland. illustrated by wood engravings, and five large folding plates. to., cloth; about pages. $ . $hughes.--american miller and millwright's assistant$: by william carter hughes. mo. $ . $hulme.--worked examination questions in plane geometrical drawing$: for the use of candidates for the royal military academy, woolwich; the royal military college, sandhurst; the indian civil engineering college, cooper's hill; indian public works and telegraph departments; royal marine light infantry; the oxford and cambridge local examinations, etc. by f. edward hulme, f.l.s., f.s.a., art-master marlborough college. illustrated by examples. small quarto. $ . $jervis.--railroad property$: a treatise on the construction and management of railways; designed to afford useful knowledge, in the popular style, to the holders of this class of property; as well as railway managers, officers, and agents. by john b. jervis, late civil engineer of the hudson river railroad, croton aqueduct, etc. mo., cloth $ . $keene.--a hand-book of practical gauging$: for the use of beginners, to which is added a chapter on distillation, describing the process in operation at the custom-house for ascertaining the strength of wines. by james b. keene, of h.m. customs. vo. $ . $kelley.--speeches, addresses, and letters on industrial and financial questions$: by hon. william d. kelley, m.c. pages, vo. $ . $kellogg.--a new monetary system$: the only means of securing the respective rights of labor and property, and of protecting the public from financial revulsions. by edward kellogg. revised from his work on "labor and other capital." with numerous additions from his manuscript. edited by mary kellogg putnam. $fifth edition.$ to which is added a biographical sketch of the author. one volume, mo. paper cover. $ . bound in cloth. $ . $kemlo.--watch-repairer's hand-book$: being a complete guide to the young beginner, in taking apart, putting together, and thoroughly cleaning the english lever and other foreign watches, and all american watches. by f. kemlo, practical watchmaker. with illustrations. mo. $ . $kentish.--a treatise on a box of instruments$, and the slide rule; with the theory of trigonometry and logarithms, including practical geometry, surveying, measuring of timber, cask and malt gauging, heights, and distances. by thomas kentish. in one volume, mo. $ . $kerl.--the assayer's manual$: an abridged treatise on the docimastic examination of ores, and furnace and other artificial products. by bruno kerl, professor in the royal school of mines; member of the royal technical commission for the industries, and of the imperial patent-office, berlin. translated from the german by william t. brannt, graduate of the royal agricultural college of eldena, prussia. edited by william h. wahl, ph. d., secretary of the franklin institute, philadelphia. illustrated by sixty-five engravings. vo. $ . $kingzett.--the history, products, and processes of the alkali trade$: including the most recent improvements. by charles thomas kingzett, consulting chemist. with illustrations. vo. $ . $kinsley.--self-instructor on lumber surveying$: for the use of lumber manufacturers, surveyors, and teachers. by charles kinsley, practical surveyor and teacher of surveying. mo. $ . $kirk.--the founding of metals$: a practical treatise on the melting of iron, with a description of the founding of alloys; also, of all the metals and mineral substances used in the art of founding. collected from original sources. by edward kirk, practical foundryman and chemist. illustrated. third edition. vo. $ . $kittredge.--the compendium of architectural sheet-metal work$: profusely illustrated. embracing rules and directions for estimates, items of cost, nomenclature, tables of brackets, modillions, dentals, trusses, stop-blocks, frieze pieces, etc. architect's specification, tables of tin-roofing, galvanized iron, etc., etc. to which is added the exemplar of architectural sheet-metal work, containing details of the centennial buildings, and other important sheet-metal work, designs and prices of architectural ornaments, as manufactured for the trade by the kittredge cornice and ornament company, and a catalogue of cornices, window-caps, mouldings, etc., as manufactured by the kittredge cornice and ornament company. the whole supplemented by a full index and table of contents. by a.o. kittredge. vo., pages. $landrin.--a treatise on steel$: comprising its theory, metallurgy, properties, practical working, and use. by m.h.c. landrin, jr., civil engineer. translated from the french, with notes, by a.a. fesquet, chemist and engineer. with an appendix on the bessemer and the martin processes for manufacturing steel, from the report of abram s. hewitt, united states commissioner to the universal exposition, paris, . mo. $ . $larden.--a school course on heat$: by w. larden, m.a. pp. mo. $ . $lardner.--the steam-engine$: for the use of beginners. by dr. lardner. illustrated. mo. $. $larkin.--the practical brass and iron founder's guide$: a concise treatise on brass founding, moulding, the metals and their alloys, etc.; to which are added recent improvements in the manufacture of iron, steel by the bessemer process, etc., etc. by james larkin, late conductor of the brass foundry department in reany, neafie & co.'s penn works, philadelphia. fifth edition, revised, with extensive additions. mo. $ . $leroux.--a practical treatise on the manufacture of worsteds and carded yarns$: comprising practical mechanics, with rules and calculations applied to spinning; sorting, cleaning, and scouring wools; the english and french methods of combing, drawing, and spinning worsteds, and manufacturing carded yarns. translated from the french of charles leroux, mechanical engineer and superintendent of a spinning mill, by horatio paine, m.d., and a.a. fesquet, chemist and engineer. illustrated by twelve large plates. to which is added an appendix, containing extracts from the reports of the international jury, and of the artisans selected by the committee appointed by the council of the society of arts, london, on woolen and worsted machinery and fabrics, as exhibited in the paris universal exposition, . vo. $ . $leffel.--the construction of mill-dams$: comprising also the building of race and reservoir embankments and head-gates, the measurement of streams, gauging of water supply, etc. by james leffel & co. illustrated by engravings. vo. $ . $leslie.--complete cookery$: directions for cookery in its various branches. by miss leslie. sixtieth thousand. thoroughly revised, with the addition of new receipts. in mo., cloth $ . $lieber.--assayer's guide$: or, practical directions to assayers, miners, and smelters, for the tests and assays, by heat and by wet processes, for the ores of all the principal metals, of gold and silver coins and alloys, and of coal, etc. by oscar m. lieber. mo. $ . $love.--the art of dyeing, cleaning, scouring, and finishing, on the most approved english and french methods$: being practical instructions in dyeing silks, woolens, and cottons, feathers, chips, straw, etc. scouring and cleaning bed and window curtains, carpets, rugs, etc. french and english cleaning, any color or fabric of silk, satin, or damask. by thomas love, a working dyer and scourer. second american edition, to which are added general instructions for the use of aniline colors. vo. pages $ . $lukin.--amongst machines$: embracing descriptions of the various mechanical appliances used in the manufacture of wood, metal, and other substances. mo. $ . $lukin.--the boy engineers$: what they did, and how they did it. with plates. mo. $ . $lukin.--the young mechanic$: practical carpentry. containing directions for the use of all kinds of tools, and for construction of steam-engines and mechanical models, including the art of turning in wood and metal. by john lukin, author of "the lathe and its uses," etc. illustrated. mo $ . $main and brown.--questions on subjects connected with the marine steam-engine$: and examination papers; with hints for their solution. by thomas j. main, professor of mathematics, royal naval college, and thomas brown, chief engineer, r.n. mo., cloth. $ . $main and brown.--the indicator and dynamometer$: with their practical applications to the steam-engine. by thomas j. main, m.a.f.r., ass't s. professor royal naval college, portsmouth, and thomas brown, assoc. inst. c.e., chief engineer r.n., attached to the r.n. college. illustrated. vo. $ . $main and brown.--the marine steam-engine.$ by thomas j. main, f.r. ass't s. mathematical professor at the royal naval college, portsmouth, and thomas brown, assoc. inst. c.e., chief engineer r.n. attached to the royal naval college. with numerous illustrations. vo. $ . $martin.--screw-cutting tables, for the use of mechanical engineers$: showing the proper arrangement of wheels for cutting the threads of screws of any required pitch; with a table for making the universal gas-pipe thread and taps. by w.a. martin, engineer. vo. . $michell.--mine drainage$: being a complete and practical treatise on direct-acting underground steam pumping machinery. with a description of a large number of the best known engines, their general utility and the special sphere of their action, the mode of their application, and their merits compared with other pumping machinery. by stephen michell. illustrated by engravings. vo., pages. $ . $molesworth.--pocket-book of useful formulæ and memoranda for civil and mechanical engineers.$ by guilford l. molesworth, member of the institution of civil engineers, chief resident engineer of the ceylon railway. full-bound in pocket-book form $ . $moore.--the universal assistant and the complete mechanic$: containing over one million industrial facts, calculations, receipts, processes, trades secrets, rules, business forms, legal items, etc., in every occupation, from the household to the manufactory. by r. moore. illustrated by engravings. mo. $ . $morris.--easy rules for the measurement of earthworks$: by means of the prismoidal formula. illustrated with numerous wood-cuts, problems, and examples, and concluded by an extensive table for finding the solidity in cubic yards from mean areas. the whole being adapted for convenient use by engineers, surveyors, contractors, and others needing correct measurements of earthwork. by elwood morris, c.e. vo. $ . $morton.--the system of calculating diameter, circumference, area, and squaring the circle$: together with interest and miscellaneous tables, and other information. by james morton. second edition, enlarged, with the metric system. mo. $ . $napier.--manual of electro-metallurgy$: including the application of the art to manufacturing processes. by james napier. fourth american, from the fourth london edition, revised and enlarged. illustrated by engravings. vo. $ . $napier.--a system of chemistry applied to dyeing.$ by james napier, f.c.s. a new and thoroughly revised edition. completely brought up to the present state of the science, including the chemistry of coal tar colors, by a.a. fesquet, chemist and engineer. with an appendix on dyeing and calico printing, as shown at the universal exposition, paris, . illustrated. vo. pages $ . $neville.--hydraulic tables, coefficients, and formulæ, for finding the discharge of water from orifices, notches, weirs, pipes, and rivers$: third edition, with additions, consisting of new formulæ for the discharge from tidal and flood sluices and siphons; general information on rainfall, catchment-basins, drainage, sewerage, water supply for towns and mill power. by john neville, c.e.m.r. i.a.; fellow of the royal geological society of ireland. thick mo. $ . $newbery.--gleanings from ornamental art of every style$: drawn from examples in the british, south kensington, indian, crystal palace, and other museums, the exhibitions of and , and the best english and foreign works. in a series of exquisitely drawn plates, containing many hundred examples. by robert newbery. to. $ . $nicholls.--the theoretical and practical boiler-maker and engineer's reference book$: containing a variety of useful information for employers of labor, foremen and working boiler-makers, iron, copper, and tinsmiths, draughtsmen, engineers, the general steam-using public, and for the use of science schools and classes. by samuel nicholls. illustrated by sixteen plates, mo. $ . $nicholson.--a manual of the art of bookbinding$: containing full instructions in the different branches of forwarding, gilding, and finishing. also, the art of marbling book-edges and paper. by james b. nicholson. illustrated. mo., cloth $ . $nicolls.--the railway builder$: a hand-book for estimating the probable cost of american railway construction and equipment. by william j. nicolls, civil engineer. illustrated, full bound, pocket-book form. $ . $normandy.--the commercial handbook of chemical analysis$: or practical instructions for the determination of the intrinsic or commercial value of substances used in manufactures, in trades, and in the arts. by a. normandy. new edition, enlarged, and to a great extent rewritten. by henry m. noad, ph.d., f.r.s., thick mo. $ . $norris.--a handbook for locomotive engineers and machinists$: comprising the proportions and calculations for constructing locomotives; manner of setting valves; tables of squares, cubes, areas, etc., etc. by septimus norris, m.e. new edition. illustrated, mo. $ . $north.--the practical assayer$: containing easy methods for the assay of the principal metals and alloys. principally designed for explorers and those interested in mines. by oliver north. illustrated. mo. $nystrom.--a new treatise on elements of mechanics$: establishing strict precision in the meaning of dynamical terms: accompanied with an appendix on duodenal arithmetic and metrology. by john w. nystrom, c.e. illustrated. vo. $ . $nystrom.--on technological education and the construction of ships and screw propellers$: for naval and marine engineers. by john w. nystrom, late acting chief engineer, u.s.n. second edition, revised, with additional matter. illustrated by seven engravings. mo. $ . $o'neill.--a dictionary of dyeing and calico printing$: containing a brief account of all the substances and processes in use in the art of dyeing and printing textile fabrics; with practical receipts and scientific information. by charles o'neill, analytical chemist. to which is added an essay on coal tar colors and their application to dyeing and calico printing. by a.a. fesquet, chemist and engineer. with an appendix on dyeing and calico printing, as shown at the universal exposition, paris, . vo., pages. $ . $orton.--underground treasures$: how and where to find them. a key for the ready determination of all the useful minerals within the united states. by james orton, a.m., late professor of natural history in vassar college, n.y.; cor. mem. of the academy of natural sciences, philadelphia, and of the lyceum of natural history, new york; author of the "andes and the amazon," etc. a new edition, with additions. illustrated. $ . $osborn.--the metallurgy of iron and steel$: theoretical and practical in all its branches; with special reference to american materials and processes. by h.s. osborn, ll. d., professor of mining and metallurgy in lafayette college, easton, pennsylvania. illustrated by numerous large folding plates and wood-engravings. vo. $ . $overman.--the manufacture of steel$: containing the practice and principles of working and making steel. a handbook for blacksmiths and workers in steel and iron, wagon makers, die sinkers, cutlers, and manufacturers of files and hardware, of steel and iron, and for men of science and art. by frederick overman, mining engineer, author of the "manufacture of iron," etc. a new, enlarged, and revised edition. by a.a. fesquet, chemist and engineer. mo. $ . $overman.--the moulder's and founder's pocket guide$: a treatise on moulding and founding in green-sand, dry-sand, loam, and cement; the moulding of machine frames, mill-gear, hollow-ware, ornaments, trinkets, bells, and statues; description of moulds for iron, bronze, brass, and other metals; plaster of paris, sulphur, wax, etc.; the construction of melting furnaces, the melting and founding of metals; the composition of alloys and their nature, etc., etc. by frederick overman, m.e. a new edition, to which is added a supplement on statuary and ornamental moulding, ordnance, malleable iron castings, etc. by a.a. fesquet, chemist and engineer. illustrated by engravings. mo. $ . $painter, gilder, and varnisher's companion$: containing rules and regulations in everything relating to the arts of painting, gilding, varnishing, glass-staining, graining, marbling, sign-writing, gilding on glass, and coach painting and varnishing; tests for the detection of adulterations in oils, colors, etc.; and a statement of the diseases to which painters are peculiarly liable, with the simplest and best remedies. sixteenth edition. revised, with an appendix. containing colors and coloring--theoretical and practical. comprising descriptions of a great variety of additional pigments, their qualities and uses, to which are added, dryers, and modes and operations of painting, etc. together with chevreul's principles of harmony and contrast of colors. mo. cloth $ . $pallett.--the miller's, millwright's, and engineer's guide.$ by henry pallett. illustrated. mo. $ . $pearse.--a concise history of the iron manufacture of the american colonies up to the revolution, and of pennsylvania until the present time.$ by john b. pearse. illustrated mo. $ . $percy.--the manufacture of russian sheet-iron.$ by john percy, m.d., f.r.s., lecturer on metallurgy at the royal school of mines, and to the advance class of artillery officers at the royal artillery institution, woolwich; author of "metallurgy." with illustrations. vo., paper cts. $perkins.--gas and ventilation$: practical treatise on gas and ventilation. with special relation to illuminating, heating, and cooking by gas. including scientific helps to engineer-students and others. with illustrated diagrams. by e.e. perkins. mo., cloth $ . $perkins and stowe.--a new guide to the sheet-iron and boiler plate roller$: containing a series of tables showing the weight of slabs and piles to produce boiler plates, and of the weight of piles and the sizes of bars to produce sheet-iron; the thickness of the bar gauge in decimals; the weight per foot, and the thickness on the bar or wire gauge of the fractional parts of an inch; the weight per sheet, and the thickness on the wire gauge of sheet-iron of various dimensions to weigh lbs. per bundle; and the conversion of short weight into long weight, and long weight into short. estimated and collected by g.h. perkins and j.g. stowe. $ . $powell--chance--harris.--the principles of glass making.$ by harry j. powell, b.a. together with treatises on crown and sheet glass; by henry chance, m.a. and plate glass, by h.g. harris, asso. m. inst. c.e. illustrated mo. $ . $proteaux.--practical guide for the manufacture of paper and boards.$ by a. proteaux. from the french, by horatio paine, a.b., m.d. to which is added the manufacture of paper from wood, by henry t. brown. illustrated by six plates. vo. $proctor.--a pocket-book of useful tables and formulæ for marine engineers.$ by frank proctor. second edition, revised and enlarged. full bound pocket-book form. $ . $regnault.--elements of chemistry.$ by m.v. regnault. translated from the french by t. forrest betton, m.d., and edited, with notes, by james c. booth, melter and refiner u.s. mint, and william l. faber, metallurgist and mining engineer. illustrated by nearly wood engravings. comprising nearly , pages. in two volumes, vo., cloth $ . $riffault, vergnaud, and toussaint.--a practical treatise on the manufacture of colors for painting$: comprising the origin, definition, and classification of colors; the treatment of the raw materials; the best formulæ and the newest processes for the preparation of every description of pigment, and the necessary apparatus and directions for its use; dryers; the testing, application, and qualities of paints, etc., etc. by mm. riffault, vergnaud, and toussaint. revised and edited by m.f. malepeyre. translated from the french, by a.a. fesquet, chemist and engineer. illustrated by eighty engravings. in one vol., vo., pages. $ . $roper.--a catechism of high-pressure, or non-condensing steam-engines$: including the modelling, constructing, and management of steam-engines and steam boilers. with valuable illustrations. by stephen roper, engineer. sixteenth edition, revised and enlarged. mo., tucks, gilt edge. $ . $roper.--engineer's handy-book$: containing a full explanation of the steam-engine indicator, and its use and advantages to engineers and steam users. with formulæ for estimating the power of all classes of steam-engines; also, facts, figures, questions, and tables for engineers who wish to qualify themselves for the united states navy, the revenue service, the mercantile marine, or to take charge of the better class of stationary steam-engines. sixth edition. mo., pages, tucks, gilt edge. $ . $roper.--hand-book of land and marine engines$: including the modelling, construction, running, and management of land and marine engines and boilers. with illustrations. by stephen roper, engineer. sixth edition. mo., tucks, gilt edge. $ . $roper.--hand-book of the locomotive$: including the construction of engines and boilers, and the construction, management, and running of locomotives. by stephen roper. eleventh edition. mo., tucks, gilt edge. $ . $roper.--hand-book of modern steam fire-engines.$ with illustrations. by stephen roper, engineer. fourth edition, mo., tucks, gilt edge. $ . $roper.--questions and answers for engineers.$ this little book contains all the questions that engineers will be asked when undergoing an examination for the purpose of procuring licenses, and they are so plain that any engineer or fireman of ordinary intelligence may commit them to memory in a short time. by stephen roper, engineer. third edition. $ . $roper.--use and abuse of the steam boiler.$ by stephen roper, engineer. eighth edition, with illustrations. mo., tucks, gilt edge. $ . $rose.--the complete practical machinist$: embracing lathe work, vise work, drills and drilling, taps and dies, hardening and tempering, the making and use of tools, tool grinding, marking out work, etc. by joshua rose. illustrated by engravings. thirteenth edition, thoroughly revised and in great part rewritten. in one vol., mo., pages. $ . $rose.--mechanical drawing self-taught$: comprising instructions in the selection and preparation of drawing instruments, elementary instruction in practical mechanical drawing, together with examples in simple geometry and elementary mechanism, including screw threads, gear wheels, mechanical motions, engines and boilers. by joshua rose, m.e., author of "the complete practical machinist," "the pattern-maker's assistant," "the slide-valve." illustrated by engravings. vo., pages. $ . $rose.--the slide-valve practically explained$: embracing simple and complete practical demonstrations of the operation of each element in a slide-valve movement, and illustrating the effects of variations in their proportions by examples carefully selected from the most recent and successful practice. by joshua rose, m.e., author of "the complete practical machinist," "the pattern-maker's assistant," etc. illustrated by engravings. $ . $ross.--the blowpipe in chemistry, mineralogy and geology$: containing all known methods of anhydrous analysis, many working examples, and instructions for making apparatus. by lieut.-colonel w.a. ross, r.a.f., g.s. with illustrations. mo. $ . $shaw.--civil architecture$: being a complete theoretical and practical system of building, containing the fundamental principles of the art. by edward shaw, architect. to which is added a treatise on gothic architecture, etc. by thomas w. silloway and george m. harding, architects. the whole illustrated by quarto plates finely engraved on copper. eleventh edition. to. $ . $shunk.--a practical treatise on railway curves and location, for young engineers.$ by william f. shunk, civil engineer. mo. full bound pocket-book form. $ . $slater.--the manual of colors and dye wares.$ by j.w. slater. mo. $ . $sloan.--american houses$: a variety of original designs for rural buildings. illustrated by twenty-six colored engravings, with descriptive references. by samuel sloan, architect, author of the "model architect," etc. etc. vo. $ . $sloan.--homestead architecture$: containing forty designs for villas, cottages, and farm-houses, with essays on style, construction, landscape gardening, furniture, etc., etc. illustrated by upwards of engravings. by samuel sloan, architect. vo. $ . $smeaton.--builder's pocket-companion$: containing the elements of building, surveying, and architecture; with practical rules and instructions connected with the subject. by a.c. smeaton, civil engineer, etc. mo. $ . $smith.--a manual of political economy.$ by e. peshine smith. a new edition, to which is added a full index. mo. $ . $smith.--parks and pleasure-grounds:$ or practical notes on country residences, villas, public parks, and gardens. by charles h.j. smith, landscape gardener and garden architect, etc., etc. mo. $ . $smith.--the dyer's instructor:$ comprising practical instructions in the art of dyeing silk, cotton, wool, and worsted, and woolen goods; containing nearly receipts. to which is added a treatise on the art of padding; and the printing of silk warps, skeins, and handkerchiefs, and the various mordants and colors for the different styles of such work. by david smith, pattern dyer. mo. $ . $smyth.--a rudimentary treatise on coal and coal-mining.$ by warrington w. smyth, m.a., f.r.g., president r.g.s. of cornwall. fifth edition, revised and corrected. with numerous illustrations. mo. $ . $snively.--a treatise on the manufacture of perfumes and kindred toilet articles.$ by john h. snively, phr. d., professor of analytical chemistry in the tennessee college of pharmacy. vo. $ . $snively.--tables for systematic qualitative chemical analysis.$ by john h. snively, phr. d. vo. $ . $snively.--the elements of systematic qualitative chemical analysis:$ a hand-book for beginners. by john h. snively, phr. d. mo. $ . $stewart.--the american system:$ speeches on the tariff question, and on internal improvements, principally delivered in the house of representatives of the united states. by andrew stewart, late m.c. from pennsylvania. with a portrait, and a biographical sketch. vo. $ . $stokes.--the cabinet-maker and upholsterer's companion:$ comprising the art of drawing, as applicable to cabinet work; veneering, inlaying, and buhl-work; the art of dyeing and staining wood, ivory, bone, tortoise-shell, etc. directions for lackering, japanning, and varnishing; to make french polish, glues, cements, and compositions; with numerous receipts, useful to workmen generally. by j. stokes. illustrated. a new edition, with an appendix upon french polishing, staining, imitating, varnishing, etc., etc. mo. $ . $strength and other properties of metals:$ reports of experiments on the strength and other properties of metals for cannon. with a description of the machines for testing metals, and of the classification of cannon in service. by officers of the ordnance department, u.s. army. by authority of the secretary of war. illustrated by large steel plates. quarto. $ . $sullivan.--protection to native industry.$ by sir edward sullivan, baronet, author of "ten chapters on social reforms." vo. $ . $syme.--outlines of an industrial science.$ by david syme. mo. $ . $tables showing the weight of round, square, and flat bar iron, steel, etc.,$ by measurement. cloth. $taylor.--statistics of coal:$ including mineral bituminous substances employed in arts and manufactures; with their geographical, geological, and commercial distribution and amount of production and consumption on the american continent. with incidental statistics of the iron manufacture. by r.c. taylor. second edition, revised by s.s. haldeman. illustrated by five maps and many wood engravings. vo., cloth. $ . $templeton.--the practical examinator on steam and the steam--engine:$ with instructive references relative thereto, arranged for the use of engineers, students, and others. by william templeton, engineer. mo. $ . $thausing.--the theory and practice of the preparation of malt and the fabrication of beer:$ with especial reference to the vienna process of brewing. elaborated from personal experience by julius e. thausing, professor at the school for brewers, and at the agricultural institute, mödling, near vienna. translated from the german by william t. brannt. thoroughly and elaborately edited, with much american matter, and according to the latest and most scientific practice, by a. schwarz and dr. a.h. bauer. illustrated by engravings. vo., pages. $ . $thomas.--the modern practice of photography:$ by r.w. thomas, f.c.s. vo. $. $thompson.--political economy. with especial reference to the industrial history of nations:$ by robert e. thompson, m.a., professor of social science in the university of pennsylvania. mo. $ . $thomson.--freight charges calculator:$ by andrew thomson, freight agent. mo. $ . $turner's (the) companion:$ containing instructions in concentric, elliptic, and eccentric turning; also various plates of chucks, tools, and instruments; and directions for using the eccentric cutter, drill, vertical cutter, and circular rest; with patterns and instructions for working them. mo. $ . $turning: specimens of fancy turning executed on the hand or foot-lathe:$ with geometric, oval, and eccentric chucks, and elliptical cutting frame. by an amateur. illustrated by exquisite photographs. to. $ . $urbin--brull.--a practical guide for puddling iron and steel.$ by ed. urbin, engineer of arts and manufactures. a prize essay, read before the association of engineers, graduate of the school of mines, of liege, belgium, at the meeting of - . to which is added a comparison of the resisting properties of iron and steel. by a. brull. translated from the french by a.a. fesquet, chemist and engineer. vo. $ . $vaile.--galvanized-iron cornice-worker's manual:$ containing instructions in laying out the different. mitres, and making patterns for all kinds of plain and circular work. also, tables of weights, areas and circumferences of circles, and other matter calculated to benefit the trade. by charles a. vaile. illustrated by twenty-one plates. to. $ . $ville.--on artificial manures:$ their chemical selection and scientific application to agriculture. a series of lectures given at the experimental farm at vincennes, during and - . by m. georges ville. translated and edited by william crookes, f.r.s. illustrated by thirty-one engravings. vo., pages. $ . $ville.--the school of chemical manures:$ or, elementary principles in the use of fertilizing agents. from the french of m. geo. ville, by a.a. fesquet, chemist and engineer. with illustrations. mo. $ . $vogdes.--the architect's and builder's pocket-companion and price-book:$ consisting of a short but comprehensive epitome of decimals, duodecimals, geometry and mensuration; with tables of united states measures, sizes, weights, strengths, etc., of iron, wood, stone, brick, cement and concretes, quantities of materials in given sizes and dimensions of wood, brick and stone; and full and complete bills of prices for carpenter's work and painting; also, rules for computing and valuing brick and brick work, stone work, painting, plastering, with a vocabulary of technical terms, etc. by frank w. vogdes, architect, indianapolis, ind. enlarged, revised, and corrected. in one volume, pages, full-bound, pocket-book form, gilt edges. $ . cloth . $wahl.--galvanoplastic manipulations:$ a practical guide for the gold and silver electroplater and the galvanoplastic operator. comprising the electro-deposition of all metals by means of the battery and the dynamo-electric machine, as well as the most approved processes of deposition by simple immersion, with descriptions of apparatus, chemical products employed in the art, etc. based largely on the "manipulations hydroplastiques" of alfred roseleur. by william h. wahl, ph. d. (heid), secretary of the franklin institute. illustrated by engravings. vo., pages. $ . $walton.--coal-mining described and illustrated:$ by thomas h. walton, mining engineer. illustrated by large and elaborate plates, after actual workings and apparatus. $ . $ware.--the sugar beet.$ including a history of the beet sugar industry in europe, varieties of the sugar beet, examination, soils, tillage, seeds and sowing, yield and cost of cultivation, harvesting, transportation, conservation, feeding qualities of the beet and of the pulp, etc. by lewis s. ware, c.e., m.e. illustrated by ninety engravings. vo. $ . $warn.--the sheet-metal worker's instructor:$ for zinc, sheet-iron, copper, and tin-plate workers, etc. containing a selection of geometrical problems; also, practical and simple rules for describing the various patterns required in the different branches of the above trades. by reuben h. warn, practical tin-plate worker. to which is added an appendix, containing instructions for boiler-making, mensuration of surfaces and solids, rules for calculating the weights of different figures of iron and steel, tables of the weights of iron, steel, etc. illustrated by thirty-two plates and thirty-seven wood engravings. vo. $ . . $warner.--new theorems, tables, and diagrams, for the computation of earth-work:$ designed for the use of engineers in preliminary and final estimates, of students in engineering, and of contractors and other non-professional computers. in two parts, with an appendix. part i. a practical treatise; part ii. a theoretical treatise, and the appendix. containing notes to the rules and examples of part i.; explanations of the construction of scales, tables, and diagrams, and a treatise upon equivalent square bases and equivalent level heights. the whole illustrated by numerous original engravings, comprising explanatory cuts for definitions and problems, stereometric scales and diagrams, and a series of lithographic drawings from models: showing all the combinations of solid forms which occur in railroad excavations and embankments. by john warner, a.m., mining and mechanical engineer. illustrated by plates. a new, revised and improved edition. vo. $ . $watson.--a manual of the hand-lathe:$ comprising concise directions for working metals of all kinds, ivory, bone and precious woods; dyeing, coloring, and french polishing; inlaying by veneers, and various methods practised to produce elaborate work with dispatch, and at small expense. by egbert p. watson, author of "the modern practice of american machinists and engineers." illustrated by engravings. $ . $watson.--the modern practice of american machinists and engineers:$ including the construction, application, and use of drills, lathe tools, cutters for boring cylinders, and hollow-work generally, with the most economical speed for the same; 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to which is added a list of valuable tables, rules, and receipts, by foster wilson. mo. $ . $wilson.--first principles of political economy:$ with reference to statesmanship and the progress of civilization. by professor w.d. wilson, of the cornell university. a new and revised edition. mo. $ . $wÃ�hler.--a hand-book of mineral analysis.$ by f. wÃ�hler, professor of chemistry in the university of göttingen. edited by henry b. nason, professor of chemistry in the renssalaer polytechnic institute, troy, new york. illustrated mo. $ . $worssam.--on mechanical saws:$ from the transactions of the society of engineers, . by s.w. worssam, jr. illustrated by eighteen large plates. vo. $ . * * * * * $recent additions.$ $anderson--the prospector's hand-book:$ a guide for the prospector and traveler in search of metal bearing or other valuable minerals. by j.w. anderson. illustrations. mo. $ . $bilgram.--slide-valve gears:$ a new, graphical method for analyzing the action of slide-valves, moved by eccentrics, link motions, and cut-off gears, offering easy means for properly designing valves and valve-gears, and for establishing the comparative merits of their various constructions. by hugo bilgram, m.e. illustrated. mo. $ . $crew.--a practical treatise on petroleum:$ comprising its geographical distribution, its geology, chemistry, mining, refining, preparation, and uses. together with a description of gas wells and the application of gas as fuel, etc. by benjamin j. crew. illustrated. vo. (in preparation.) $crookes.--select methods in chemical analysis (chiefly inorganic):$ by william crookes, f.r.s., v.p.c.s. d edition, re-written and greatly enlarged. illustrated by wood-cuts. pp. vo. $ . $davis.--a treatise on steam-boiler incrustation and methods for preventing corrosion and the formation of scale:$ by charles t. davis. illustrated by engravings. vo. $ . $davis.--the manufacture of paper:$ being a description of the various processes for the fabrication, coloring and finishing of every kind of paper, including the different raw materials and the methods for determining their values, the tools, machines and practical details connected with an intelligent and a profitable prosecution of the art, with special reference to the best american practice. to which are added a history of paper, complete lists of paper-making materials, list of american machines, tools and processes used in treating the raw materials, and in making, coloring and finishing paper. by charles t. davis. illustrated by engravings. pages, vo. $ . $hand-book of useful tables for the lumberman, farmer and mechanic:$ containing accurate tables of logs reduced to inch board measure, plank, scantling and timber measure; wages and rent, by week or month; capacity of granaries, bins and cisterns; land measure, interest tables, with directions for finding the interest on any sum at , , , and per cent., and many other useful tables. mo., boards. pages . $makins.--a manual of metallurgy:$ by george hogarth makins, m.r.c.s.s.c.s. illustrated by engravings. second edition rewritten and much enlarged. vo., pages. $ . $roper.--instructions and suggestions for engineers and firemen:$ by stephen roper, engineer $ . $roper.--the steam boiler: its care and management:$ by stephen roper, engineer. mo., tuck, gilt edges. $ . $roper.--the young engineer's own book:$ containing an explanation of the principle and theories on which the steam engine as a prime mover is based. by stephen roper, engineer. illustrations, pages. mo., tuck $ . $rose.--modern steam-engines:$ an elementary treatise upon the steam-engine, written in plain language; for use in the workshop as well as in the drawing office. giving full explanations of the construction of modern steam-engines: including diagrams showing their actual operation. together with complete but simple explanations of the operations of various kinds of valves, valve motions, and link motions, etc., thereby enabling the ordinary engineer to clearly understand the principles involved in their construction and use, and to plot out their movements upon the drawing board. by joshua rose, m.e., author of "the complete practical machinist," "the pattern maker's assistant," "the slide valve" and "mechanical drawing self-taught." illustrated by over engravings. in one volume, to, pages. $ . $a great repository of practical and scientific information.$ * * * * * one of the fullest, freshest and most valuable hand-books of the age. indispensable to every practical man. just ready. $price, $ . $ $free of postage to any address in the world.$ $the techno-chemical receipt book:$ containing several thousand receipts, covering the latest, most important and most useful discoveries in chemical technology, and their practical application in the arts and the industries. edited chiefly from the german of drs. winckler, eisner, heintze, mierzinski, jacobsen, koller, and heinzerling, with additions by $william t. brannt,$ graduate of the royal agricultural college of eldena, prussia, and $william h. wahl, ph. d. (heid.),$ secretary of the franklin institute, philadelphia; author of "galvanoplastic manipulations." $illustrated by seventy-eight engravings.$ in one volume, xxxii, pages, mo., closely printed, containing an immense amount and a great variety of matter. price $ . , free of postage to any address in the world. »_the above or any of our books sent by mail, free of postage, at the publication price, to any address in the world._ »_our new and enlarged catalogue of practical and scientific books, pages, vo., and our other catalogues, the whole covering every branch of science applied to the arts, sent free and free of postage to any one, in any part of the world, who will furnish his address._ $henry carey baird & co., industrial publishers, booksellers and importers, walnut street, philadelphia, pa., u.s.a.$ transcriber's notes: opening quote on folio page was eliminated due to ambiguity of the extent of the quote: quote: "but these circular arcs.... conventional text emphasis coding $...$ used for bolded text. twentieth century inventions a forecast by george sutherland, m.a. longmans, green, and co. paternoster row, london new york and bombay preface. twenty years ago the author started a career in technological journalism by writing descriptions of what he regarded as the most promising inventions which had been displayed in international exhibitions then recently held. from that time until the present it has been his constant duty and practice to take note of the advance of inventive science as applied to industrial improvement--to watch it as an organic growth, not only from a philosophical, but also from a practical, point of view. the advance towards the actual adoption of any great industrial invention is generally a more or less collective movement; and, in the course of a practice such as that referred to, the habit of watching the signs of progress has been naturally acquired. moreover, it has always been necessary to take a comprehensive, rather than a minute or detailed, view of the progress of the great industrial army of nineteenth century civilisation towards certain objectives. it is better, for some purposes of technological journalism, to be attached to the staff than to march with any individual company--for the war correspondent must ever place himself in a position from which a bird's-eye view is possible. the personal aspect of the campaign becomes merged in that which regards the army as an organic unit. it may, therefore, be claimed that, in some moderate degree, the author is fitted by training and opportunities for undertaking the necessarily difficult task of foretelling the trend of invention and industrial improvement during the twentieth century. he must, of course, expect to be wrong in a certain proportion of his prognostications; but, like the meteorologists, he will be content if in a fair percentage of his forecasts it should be admitted that he has reasoned correctly according to the available data. the questions to be answered in an inquiry as to the chances of failure or success which lie before any invention or proposed improvement are, first, whether it is really wanted; and, secondly, whether the environment in the midst of which it must make its début is favourable. these requirements generally depend upon matters which, to a large extent, stand apart from the personal qualifications of any individual inventor. in the course of a search through the vast accumulations of the patent specifications of various countries, the thought is almost irresistibly forced upon the mind of the investigator that "there is nothing new under the sun". no matter how far back he may push his inquiry in attempting to unveil the true source of any important idea, he will always find at some antecedent date the germ, either of the same inventive conception, or of something which is hardly distinguishable from it. the habit of research into the origin of improved industrial method must therefore help to strengthen the impression of the importance of gradual growth, and of general tendencies, as being the prime factors in promoting social advancement through the success of invention. the same habit will also generally have the effect of rendering the searcher more diffident in any claims which he may entertain as to the originality of his own ideas. inventive thought has been so enormously stimulated during the past two or three generations, that the public recognition of a want invariably sets thousands of minds thinking about the possible methods of ministering to it. startling illustrations of this fact are continually cropping up in the experiences of patent agents and others who are engaged in technological work and its literature. the average inventor is almost always inclined to imagine--when he finds another man working in exactly the same groove as himself--that by some means his ideas have leaked out, and have been pirated. but those who have studied invention, as a social and industrial force, know that nothing is more common than to find two or more inventors making entirely independent progress in the same direction. for example, while this book was in course of preparation the author wrote out an account of an application of wireless telegraphy to the purpose of keeping all the clocks within a given area correct to one standard time. within a few days there came to hand a copy of _engineering_ in which exactly the same suggestion was put forward, and an announcement was made to the effect that mr. richard kerr, f.g.s., had been working independently on the same lines, the details of his method of applying the hertzian waves to the purpose being practically the same as those sketched out by the author. this is only one of several instances of coincidences in independent work which have been noticed during the period while this volume was in course of preparation. it may, therefore, be readily understood that the author would hardly like to undertake the task of attempting to discriminate between those forecasts in the subsequent pages which are the results of his own original suggestions, and those which have been derived from other sources. whatever is of value has in all probability been thought of, or perhaps patented and otherwise publicly suggested, before. at any rate, the great majority of the forecasts are based on actual records of the trials of inventions which distinctly have a future lying before them in the years of the twentieth century. in declining to enter into questions relating to the original authorship of the improvements or discoveries discussed, it should not be supposed that any wish is implied to detract from the merits of inventors and promoters of inventions, either individually or collectively. many of these are the heroes and statesmen of that great nation which is gradually coming to be recognised as a true entity under the name of civilisation. their life's work is to elevate humanity, and if mankind paid more attention to them, and to what they are thinking and doing, instead of setting so much store by the veriest tittle-tattle of what is called political life, it would make much faster progress. some of the industrial improvements referred to in the succeeding pages are necessarily sketched in an indefinite manner. the outlines, as it were, have been only roughed in; and no attempt has been made to supply particulars, which in fact would be out of place in an essay towards a comprehensive survey in so small a space. it is upon the wise and skilful arrangement of details that sound and commercially profitable patents are usually founded, rather than upon the broad general principles of a proposed industrial advance or reform. during the twentieth century this latter fact, already well recognised by experts in what is known as industrial property, will doubtless force itself more and more upon the attention of inventors. every specification will require to be drawn up with the very greatest care in observing the truth taught by the fable of the boy and the jar of nuts. so rapidly does the mass of bygone patent records accumulate, that almost any kind of claim based upon very wide foundations will be found to have trenched upon ground already in some degree taken up. probably there is hardly anything indicated in this work which is not--in the strict sense of the rules laid down for examiners in those countries which make search as to originality--common public property. the labour involved in gathering the data for a forecast of the inventions likely to produce important effects during the twentieth century has been chiefly that of selecting from out of a vast mass of heterogeneous ideas those which give promise of springing up amidst favourable conditions and of growing to large proportions and bearing valuable fruit. such ideas, when planted in the soil of the collective mind through the medium of official or other records, generally require for their germination a longer time than that for which the patent laws grant protection for industrial property. many of them, indeed, have formed the subjects of patents which, from one reason or another, lapsed long before the expiration of the maximum terms. nature is ever prodigal of seeds and of "seed-thoughts" but comparatively niggardly of places in which the young plant will find exactly the kind of soil, air, rain, and sunshine which the young plant needs. if any one requires proof of this statement he will find ample evidence in support of it in the tenth chapter of smiles's work on _industrial biography_, where facts and dates are adduced to show that steam locomotion, reaping machines, balloons, gunpowder, macadamised roads, coal gas, photography, anæsthesia, and even telegraphy are inventions which, so far as concerns the germ idea on which their success has been based, are of very much older origin than the world generally supposes. the author, therefore, submits that he is justified in referring inventions to the century in which they produce successful results, not to that in which they may have been first vaguely thought of. and in this view it is obvious that many of those patents and suggestions which have been published in current literature during the nineteenth century, but which, although pregnant with mighty industrial influences, have not yet reached fruition, are essentially inventions of the twentieth century. more than this, it is extremely probable that the great majority of those ideas which will move the industrial world during the next ensuing hundred years have already been indicated, more or less clearly, by the inventive thought of the nineteenth century. george sutherland. _december_, . contents. page chapter i. inventive progress chapter ii. natural power chapter iii. storage of power chapter iv. artificial power chapter v. road and rail chapter vi. ships chapter vii. agriculture chapter viii. mining chapter ix. domestic chapter x. electric messages, etc. chapter xi. warfare chapter xii. music chapter xiii. art and news chapter xiv. invention and collectivism chapter i. inventive progress. the year , the first of the nineteenth century, was _annus mirabilis_ in the industrial history of mankind. it was in that year that the railway locomotive was invented by richard trevithick, who had studied the steam engine under a friend and assistant of james watt. his patent, which was secured during the ensuing year, makes distinct mention of the use of his locomotive driven by steam upon tramways; and in he actually had an engine running on the pen-y-darran mining tramway in cornwall. from that small beginning has grown a system of railway communication which has brought the farthest inland regions of mighty continents within easy reach of the seaboard and of the world's great markets; which has made social and friendly intercourse possible in millions of homes which otherwise would have been almost destitute of it; which has been the means of spreading a knowledge of literature, science and religion over the face of the civilised world; and which, at the present moment, constitutes the outward and visible sign of the difference between western civilisation and that of the asiatic, as seen in china. in another corner of the globe, during the year , volta was constructing his first apparatus demonstrating the material and physical nature of those mysterious electric currents which his friend professor galvani of bologna, who died just two years earlier, had at first ascribed to a physiological source. the researches of the latter, it will be remembered, were begun in an observation of the way in which the legs of a dead frog twitched under certain conditions. the voltaic pile was the first electric battery, and, therefore, the parent of the existing marvellous telegraphic and telephonic systems, while less immediately it led to the development of the dynamo and its work in electric lighting and traction. it brought into harmony much fragmentary knowledge which had lain disjointed in the armoury of the physicist since dufay in france and franklin in america had investigated their theories of positive and negative frictional electricities, and had connected them with the flash of lightning as seen in nature. thus it became a fresh starting point both for industry and for science. at the exposition of national industry, held in paris during the year , a working model of the jacquard loom was exhibited--the prototype of those remarkable pieces of mechanism by which the most elaborately figured designs are worked upon fabrics during the process of weaving by means of sets of perforated cardboards. this was the crowning achievement of the inventions relating to textile fabrics, which had rendered the latter half of the eighteenth century so noteworthy in an industrial sense. it brought artistic designs in articles of common use within the reach of even poor people, and has been the means of unconsciously improving the public taste, in matters of applied art, more rapidly than could have been accomplished by an army of trained artists. the riots in which the mob nearly drowned jacquard at lyons for attempting to set up some of his looms were very nearly a counterpart of those which had occurred in england in connection with the introduction of spinning, weaving and knitting machinery. in paris, during the first year of the nineteenth century, robert fulton, an american, and friend of the united states representative in france, was making trials on the seine with his first steam-boat--a little vessel imitated by him later on in the first successful steamers which plied on the river hudson, carrying passengers from new york. at the same time, william symongton launched the _charlotte dundas_, the steam tug-boat which, on the scottish canals, did the first actually useful work in the conveyance of goods by steam power on the water. these small experiments have initiated a movement in maritime transport which is fully comparable to that brought about on land by the invention of the railway locomotive. again, in , sir humphry davy gave his first lecture at the royal institution in london, where he had just been installed as a professor, and began that long series of investigations into the chemistry of common things which, taken up by his successor faraday, gave to the united kingdom the first start in some of those industries depending upon a knowledge of organic chemistry and the use of certain essential oils. public attention at the beginning of the nineteenth century, however, was directed anywhere but towards these small commencements of mighty forces which were to revolutionise the industrial world, and through it also the social and political. if in those days cornwall was ever referred to, it was not by any means in connection with trevithick and his steam-engine which would run on rails, but by way of reference to the relations of the prince of wales to the duchy, and the proportion of its revenues which belonged to him from birth. glancing over the pages of any history compiled in the early half of the century, the eye will trace hardly the barest allusions to forces, the discoveries in which were, in the year , still in the incipient stage. canon hughes, for instance, in his continuation of the histories of hume and smollett, devoted some forty pages to the record of that year. the space which he could spare from the demands made upon his attention by the wars in spain and egypt, and the naval conflict with france, was mainly occupied with such matters as the election of the rev. horne tooke for old sarum, and the burning question as to whether that gentleman had not rendered himself permanently ineligible for parliamentary honours through taking holy orders, and with a miscellaneous mass of topics relating to the merely evanescent politics of the day. the whole of the effects of invention and discovery in making history during the first year of the century were dismissed by this writer with a casual reference to the augmentation of the productive power of the labouring population through the use of machinery, and a footnote stating that "this was more particularly the case in the cotton manufacture". time corrects the historical perspective of the past, but it does not very materially alter the power of the historical vision to adjust itself to an examination of the present day forces which are likely to grow to importance in the making of future history. when we ask what are the inventions and discoveries which are really destined to grow from seeds of the nineteenth into trees of the twentieth century, we are at once confronted with the same kind of difficulty which would present itself to one who, standing in the midst of an ancient forest, should be requested to indicate in what spots the wide-spreading giants of the next generation of trees might be expected to grow. the company promoter labels those inventions in which he is commercially interested as the affairs which will grow to huge dimensions in the future; while the man of scientific or mechanical bent is very apt to predict a mighty future only for achievements which strike him as being peculiarly brilliant. patent experts, on the other hand, when asked by their clients to state candidly what class of inventions may be relied upon to bring the most certain returns, generally reply that "big money usually comes from small patents". in other words, an invention embodying some comparatively trivial, but yet really serviceable, improvement on a very widely used type of machine; or a little bit of apparatus which in some small degree facilitates some well known process; or a fashionable toy or puzzle likely to have a good run for a season or two, and then a moderate sale for a few years longer; these are the things to be recommended to an inventor whose main object is to make money. thus the most qualified experts in patent law and practice do not fail to disclose this fact to those who seek their professional advice in a money-making spirit, as the great majority of inventors do. the full term of fourteen years in the united kingdom, or seventeen in the united states, may be a ridiculously long period for which to grant a monopoly to the inventor of some ephemeral toy, although absolutely inadequate to secure the just reward for one who labours for many years to perfect an epoch-making invention, and then to introduce it to the public in the face of all the opposition from vested interests which such inventions almost invariably meet. thus the fact that a man has made money out of one class of patents may not be any safe guide at all to arriving at a due estimate of his ideas on industrial improvements of greater "pith and moment," but, on the contrary, it is generally exactly the reverse. the law offers an immense premium for such inventions as are readily introduced, and the inventor who has made it his business to take advantage of this fact is usually one of the last men from whom to get a trustworthy opinion on patents of a different class. of the patents taken out during the latter portion of the nineteenth century, many undoubtedly contain the germs of great ideas, and, nevertheless, have excited comparatively little attention from business men or from the general public. it was so in the latter part of the eighteenth century, and history is only repeating itself when the seeds of twentieth century industrial movements are permitted to germinate unseen. for all practical purposes each invention must be referred to the age in which it actually does useful work in the service of mankind. thus, hero of alexandria, in the third century b.c., devised a water fountain worked by the expansive power of steam. from time to time during the succeeding twenty centuries similar pieces of apparatus excited the curiosity of the inquisitive and the interest of the learned. the clever and eccentric marquis of worcester, in his little book published in , _a century of the names and scantlings of inventions_, generally known as the _century of inventions_, gave an account of one application of the power of steam to lift water which he had worked out, probably on a scale large enough to have become of practical service. thomas savery and denis papin, both of them men of high attainments and great ingenuity, made important improvements before the end of the seventeenth century. yet, if we refer to the question as to the proper age to which the steam-engine as a useful invention is to be assigned, we shall unhesitatingly speak of it as an eighteenth century invention, and this notwithstanding the fact that savery's patent for the first pumping engine which came into practical use was dated . the real introduction of steam as a factor in man's daily work was effected later on, partly by savery himself and partly by newcomen, and above all by james watt. the expiration of watt's vital patent occurred in , and he himself then retired from the active supervision of his engineering business, having virtually finished his great life's work on the last year of the century which he had marked for all time by the efforts of his genius. similarly we may confidently characterise the locomotive engine as an invention belonging to the first half of the nineteenth century, although tramways on the one hand, and steam-engines on the other hand, were ready for the application of steam transport, and the only work that remained to be accomplished in the half century indicated was the bringing of the two things together. the dynamo, as a factor in human life--or, in other words, the electric current as a form of energy producing power and light--is an invention of the second half of the nineteenth century, although the main principles upon which it was built were worked out prior to the year . it will be seen, in the course of the subsequent pages, that portable electric power has as yet won its way only into very up-to-date workshops and mines, and that the means by which it will be applied to numerous useful purposes in the field, the road, and the house will be distinctly inventions of the twentieth century. similarly the steam-engine has not really been placed upon the ordinary road, although efforts have been made for more than a century to put it there, the conception of a road locomotive being, in fact, an earlier one than that of an engine running on rails. steam automobiles and traction engines are still confined to special purposes, the natures of which prove that certain elements of adaptability are still lacking in order to render them universally useful as are the locomotive and the steam-ship. in nearly every other important line of human needs and desires it will be found that merely tentative efforts have been made by ingenious minds resulting in inventions of greater or less promise. many of the finest conceptions which have necessarily been set down as failures have missed fulfilling their intended missions, not so much by reason of inherent weakness, as through the want of accessory circumstances to assist them. as in biology, so in industrial progress the definition of fitness appended to the law of the survival of the fittest must have reference to the environment. a foolish law or public prejudice results in the temporary failure of a great invention, and the inventor's patent succumbs to the inexorable operation of the struggle for existence. yet, fortunately for mankind, if not for the individual inventor, an idea does not suffer extinction as the penalty for non-success in the struggle. "the beginning of creation," says carlyle, "is light," and the kind of light which inventors throw upon the dark problems involving man's industrial progress is providentially indestructible. twentieth century inventions--as the term is used in this book--are, therefore, those which are destined to fulfil their missions during the ensuing hundred years. they are those whose light will not only exist in hidden places, but will also shine abroad to help and to bless mankind. or, if we may revert to the former figure, they are those which have not only been planted in the seed and have germinated in the leaf, but which have grown to goodly proportions, so that none may dare to assert that they have been planted for nought. a man's age is the age in which he does his work rather than that in which he struggles to years of maturity. moore and byron were poets of the nineteenth century, although the one had attained to manhood and the other had grown from poverty to inherit a peerage before the new century dawned. the prophetic rôle--although proverbially an unsafe one--is nevertheless one which every business man must play almost every day of his life. the merchant, the manufacturer, the publisher, the director, the manager, and even the artist, must perforce stake some portion of his success in life upon the chance of his forecast as to the success of a particular speculation, article of manufacture, or artistic conception, and its prospects of proving as attractive or remunerative as he has expected it to be. the successful business man no doubt makes his plans, as far as may be practicable, upon the system indicated by the humorist, who advises people never to prophesy unless they happen to know, but the nature of his knowledge is almost always to some extent removed from certainty. he may spend much time in laborious searching; make many inquiries from persons whom he believes to be competent to advise him; diligently study the conditions upon which the problem before him depends--in short, he may take every reasonable precaution against the chances of failure, yet, in spite of all, he must necessarily incur risks. and so it is with regard to the task of forecasting the trend of industrial improvement. all who are called upon to lay their plans for a number of years beforehand must necessarily be deeply interested in the problems relating to the various directions which the course of that improvement may possibly take. meanwhile their estimates of the future, although based upon an intimate knowledge of the past and aided by naturally clear powers of insight, must be hypothetical and conditional. unfortunately for the vast majority of manufacturing experts, the thoroughness with which they have mastered the details of one particular branch of industry too often blinds them to the chances of change arising from localities beyond their own restricted fields of vision. the merriment occasioned by the first proposals for affixing pneumatic tyres to bicycles may be cited as a striking instance of the lack of forecasting insight displayed by very many of those who are best entitled to pronounce opinions on the minutiae of their particular avocations. in almost every "bike" shop and factory throughout the united kingdom and america, the suggestion of putting an air-filled hosepipe around each wheel of the machine to act as a tyre was received with shouts of ridicule! railway men, who understood the wonderful elasticity imparted by air to pieces of mechanism, such as the pneumatic brake, were not by any means so much inclined to laughter; but naturally, for the most part, they deferred to the rule which enjoins every man to stick to his trade. the rule in question--when applied to the task of estimating the worth of inventions claiming to produce revolutionary effects in any industry--is necessarily, in the majority of cases, more or less irrelevant, because such an invention should be regarded not so much as a proposed _innovation_ in an old trade as the _creation_ of a new one. george stephenson's ideas on the transport of passengers and goods were almost unanimously condemned by the experts of his day who were engaged in that line of business. on points relating to wheels of waggons and the harness of horses, the opinions of these men were probably worth something; but in relation to steam locomotives, carriages and trucks running upon rails, their judgment was not merely worthless, but a good deal worse; it was indeed actually misleading, because based on a pretence of knowledge of a trade which was to be called into existence to compete with their own. "great is diana of the ephesians" said the artificers of old; and on the strength of their expert knowledge in the making of idols they set themselves up as judges of systems of theology and morality. the argument, although based on self-interest subjectively, was nevertheless intended to carry weight even among persons who wished to judge the questions in dispute according to their merits, and most of the latter were only too ready to accept the implied dictum that men who work about a temple must be experts in theology! the principles upon which royal commissions and select committees are sometimes appointed and entrusted with the onerous duty of deciding upon far-reaching industrial problems, affecting the progress of trade and manufactures in the present day, involve exactly the same kind of fallacy. men are selected to pronounce judgment upon the proposals of their rivals in trade, and narrow-minded specialists to give their opinions upon projects which essentially belong to the border lands between two or more branches of industry, and cannot be understood by persons not possessing a knowledge of both. yet the world's work goes on apace; and as capital is accumulated and seeks to find new outlets the multiplication of industrial projects must continue in spite of every discouragement. this process will go on at a rate even faster than that which was exhibited at the beginning of the nineteenth century; but in watching the course of advancement, the world must take count of ideas rather than of the names of those who may have claims to rank as the originators of ideas. while for purposes of convenience, history labels certain great inventive movements, each with the name of one pre-eminent individual who has contributed largely to its success, nothing like a due appraisement of the services rendered by other men is ever attempted. it is not even as if the commanding general should by public acclamation receive all the applause for a successful campaign to the exclusion of his lieutenants. the pioneers in each great department of invention have generally acted as forerunners of the men whose names have become the most famous. they have borne much of the heat and burden of the day, while their successors have reaped the fruits of triumph. mr. herbert spencer's strong protest against the part assigned by some writers in the mental and industrial evolution of the human race to the influence of great men is certainly fully justified, if the attribute of greatness is to be ascribed only to those whose names figure in current histories. the parts performed by others, whose fate it may have been to have fallen into comparatively unfavourable environments, may have entitled them even more eminently to the acclamation of greatness. the world in such a matter asks, reasonably enough under the circumstances, shall we omit to honour any of the great men who have played important parts in an industrial movement, assigning as our motive the difficulty of enumerating so many names? for the encouragement of those to whom the ambition for fame acts as a great stimulus to self-devotion in the interests of human progress, it is unavoidable that some men should be singled out and made heroes, while the much more numerous class of those who have also done great work, but who have not been quite so successful, must pass out of the ken of all, excepting the few who possess an expert knowledge of the various subjects which they have taken in hand. still the distortion to which history has been subjected through its biographical mode of treatment must always be reckoned with as a factor of possible error by any one attempting to read the riddle of the past, and it may offer a still more dangerous snare to one who tries to deduce the future course of events from the evidences of the past, and the promises which they hold out. people are naturally prone to take it for granted that the world's progress during the first part of the twentieth century depends upon the future work of those inventors and industrial promoters whose names have become most famous during the latter half of the nineteenth. but this personal treatment of the subject will be found to be in the last degree unsatisfactory, when judged in the light both of past experience and of some of the utterances of those eminent inventors who have tried to forecast the future in their own particular lines of research. if, therefore, we look at the whole subject from the entirely impersonal point of view, and face the task of forecasting the progress of industry during the twentieth century, in this aspect we shall find that we have entered upon a chapter in the evolution of the human race--dealing, in fact, with a branch of anthropology. we see certain industrial and inventive forces at work, producing certain initial effects, but plainly, as yet, falling immeasurably short of an entire fulfilment of their possibilities; setting to work a multitude of busy brains, planning and arranging, and gradually preparing the minds of the more apathetic portion of humanity for the reception of new ideas and the adoption of improved methods of life and of work. whither is it all tending? will the twentieth century bring about as great a change upon the earth--man's habitat--as the nineteenth did? or have the possibilities of really great and effective industrial revolutions been practically exhausted? the belief impressed upon the author's mind, by facts and considerations evoked during the collection of materials for this book, is that the march of industrial progress is only just beginning, and that the twentieth century will witness a far greater development than the nineteenth has seen. the great majority of mankind still require to be released from the drudgery of irksome, physical exertion, which, when power has been cheapened, will be seen to be to a very large extent avoidable. pleasurable exercise will be substituted for the monotonous, manual labour which, while it continues, generally precludes the possibility of mental improvement. hygienic science will insist more strenuously than ever upon the great truth that, in order to be really serviceable in promoting the health of mind and body, physical exertion must be in some degree exhilarating, and the bad old practice of "all work and no play," which was based upon the assumption that a boy can get as much good out of chopping wood for an hour as out of a bicycle ride or a game of cricket, will be relegated to the limbo of exploded fallacies. the race, as a whole, will be athletic in the same sense in which cultured ladies and gentlemen are at present. it will, a century hence, offer a still more striking contrast to the existing state of the chinese, who bandage their women's feet in order to show that they are high born and never needed to walk or to exert themselves!--the assumption being that no one would ever move a muscle unless under fear of the lash of poverty or of actual hunger. the farther western civilisation travels from that effete eastern ideal, the greater will be the hope for human progress in physical, mental and moral well-being. chapter ii. natural power. "nature," remarked james watt when he set to work inventing his improved steam-engine, "has always a weak side if we can only find it out." many invaluable secrets have been successfully explored through the discovery of nature's "weak side" since that momentous era in the industrial history of the world; and the nineteenth century, as watt clearly foresaw, has been emphatically the age of steam power. in the condenser, the high pressure cylinder and the automatic cut-off, which utilises the expansive power of steam vapour, mankind now possesses the means of taming a monster whose capacities were almost entirely unknown to the ancients, and of bringing it into ready and willing service for the accomplishment of useful work. vaguely and loosely it is often asserted that the age of steam is now giving place to that of electricity; but these two cannot yet be logically placed in opposition to one another. no method has yet been discovered whereby the heat of a furnace can be directly converted into an electric current. the steam-engine or, as watt and his predecessors called it, the "fire-engine" is _par excellence_ the world's prime motor; and by far the greater proportion of the electrical energy that is generated to-day owes its existence primarily to the steam-engine and to other forms of reciprocating machinery designed to utilise the expansive power of vapours or gases acting in a similar manner to steam. the industrial revolutions of the coming century will, without doubt, be brought about very largely through the utilisation of nature's waste energy in the service of mankind. waterfalls, after being very largely neglected for two or three generations, are now commanding attention as valuable and highly profitable sources of power. this is only to be regarded as forming the small beginning of a movement which, in the coming century, will "acquire strength by going," and which most probably will, in less than a hundred years, have produced changes in the industrial world comparable to those brought about by the invention of the steam-engine. lord kelvin, in the year , briefly, but very significantly, classified the sources of power available to man under the five primary headings of tides, food, fuel, wind, and rain. food is the generator of animal energy, fuel that of the power obtained from steam and other mechanical expansive engines; rain, as it falls on the hill-tops and descends in long lines of natural force to the sea coasts, furnishes power to the water-wheel; while wind may be utilised to generate mechanical energy through the agency of windmills and other contrivances. the tides as a source of useful power have hardly yet begun to make their influence felt, and indeed the possibility of largely using them is still a matter of doubt. the relative advantages of reclaiming a given area of soil for purposes of cultivation, and of converting the same land into a tidal basin in order to generate power through the inward and outward flow of the sea-water, were contrasted by lord kelvin in the statement of a problem as follows: which is the more valuable--an agricultural area of forty acres or an available source of energy equal to one hundred horse-power? the data for the solution of such a question are obviously not at hand, unless the quality of the land, its relative nearness to the position at which power might be required, and several other factors in its economic application have been supplied. still, the fact remains that very large quantities of the coastal land and a considerable quantity of expensive work would be needed for the generation, by means of the tides, of any really material quantity of power. it is strange that, while so much has been written and spoken about the possibility of turning the energy of the tides to account for power in the service of man, comparatively little attention has been paid to the problem of similarly utilising the wave-power, which goes to waste in such inconceivably huge quantities. where the tidal force elevates and depresses the sea-water on a shore, through a vertical distance of say eight feet, about once in twelve hours, the waves of the ocean will perform the same work during moderate weather once in every twelve or fifteen seconds. it is true that the moon in its attraction of the sea-water produces a vastly greater sum total of effect than the wind does in raising the surface-waves, but reckoning only that part of the ocean energy which might conceivably be made available for service it is safe to calculate that the waves offer between two and three thousand times as much opportunity for the capture of natural power and its application to useful work as the tides could ever present. in no other form is the energy of the wind brought forward in so small a compass or in so concrete a form. a steam-ship of , tons gross weight which rises and falls ten times per minute through an average height of · feet is thereby subjected to an influence equal to , horse-power. in this estimate the unit of the horse-power which has been adopted is watt's arbitrary standard of " , foot pounds per minute". the work done in raising the vessel referred to is equal to ten horse-power multiplied by the number of pounds in a ton, or, in other words, , horse-power, as stated. wind-power, again, has been to a large extent neglected since the advent of the steam-engine. the mightiest work carried out in any european country in the early part of the present century was that which the dutch people most efficiently performed in the draining of their reclaimed land by means of scores of windmills erected along their seaboard. even to the present day there are no examples of the direct employment of the power of the wind which can be placed in comparison with those still to be found on the coasts of holland. but, unfortunately for the last generation of windmill builders, the intermittent character of the power to which they had to trust completely condemned it when placed in competition with the handy and always convenient steam-engine. the wind bloweth "where it listeth," but only at such times and seasons as it listeth, and its vagaries do not suit an employer whose wages list is mounting up whether he has his men fully occupied or not. the storage of power was the great thing needful to enable the windmill to hold its own. the electrical storage battery, compressed air, and other agencies which will be referred to later on, have now supplied this want of the windmill builder, but in the meantime his trade has been to a large extent destroyed. for its revival there is no doubt that, as lord kelvin remarked in the address already quoted, "the little thing wanted to let the thing be done is cheap windmills." this, however, leads to another part of the problem. the costliness of the best modern patterns of windmill as now so extensively used, particularly in america, is mainly due to the elaborate, and, on the whole, successful attempts at minimising the objection of the intermittent nature of the source of power. to put the matter in another way, it may be said that lightness, and sensitiveness to the slightest breeze, have had to be conjoined with an eminent degree of safety in the severest gale, so that the most complicated self-regulating mechanisms have been rendered absolutely imperative. once the principle of storage is applied, the whole of the conditions in this respect are revolutionised. there is no need to attempt the construction of wind-motors that shall run lightly in a soft zephyr of only five or six miles an hour, and stability is the main desideratum to be looked to. the fixed windmill, which requires no swivel mechanism and no vane to keep it up to the wind, is the cheapest and may be made the most substantial of all the forms of wind-motor. in its rudimentary shape this very elementary windmill resembles a four-bladed screw steam-ship propeller. the wheel may be constructed by simply erecting a high windlass with arms bolted to the barrel at each end, making the shape of a rectangular cross. but those at one end are fixed in such positions that when viewed from the side they bisect the angles made by those at the other side. sails of canvas or galvanised iron are then fastened to the arms, the position of which is such that the necessary obliquity to the line of the barrel is secured at once. looking at this elementary and at one time very popular form of windmill, and asking ourselves what adaptation its general principle is susceptible of in order that it may be usefully employed in conjunction with a storage battery, we find, at the outset, that, inasmuch as the electric generator requires a high speed, there is every inducement to greatly lengthen the barrel and at the same time to make the arms of the sails shorter, because short sails give in the windmill the high rate of speed required. we are confronted, in fact, with the same kind of problem which met the constructors of turbine steam-engines designed for electric lighting. the object was to get an initial speed which would be so great as to admit of the coupling of the dynamo to the revolving shaft of the turbine steam-motor, without the employment of too much reducing gear. in the case of the wind-motor the eighteenth century miller was compelled to make the arms of his mill of gigantic length, so that, while the centre of the wind pressure on each arm was travelling at somewhere near to the rate of the wind, the axis would not be running too fast and the mill stones would never be grinding so rapidly as to "set the _tems_--or the lighter parts of the corn--on fire." the dynamo for the generation of the electric current demands exactly the opposite class of conditions. we may therefore surmise that the windmill of the future, as constructed for the purposes of storing power, will have a long barrel upon which will be set numerous very short blades or sails. reducing this again to its most convenient form, it is plain that a spiral of sheet-metal wound round the barrel will offer the most convenient type of structure for stability and cheapness combined. at the end of this long barrel will be fixed the dynamo, the armature of which is virtually a part of the barrel itself, while the magnets are placed in convenient positions on the supporting uprights. from the generating dynamo the current is conveyed directly to the storage batteries, and these alone work the electric motor, which, if desired, keeps continually in motion, pumping, grinding, or driving any suitable class of machinery. it is rather surprising to find how relatively small is the advantage possessed by the vane-windmill over the fixed type in the matter of continuity of working. during about two years the author conducted a series of experiments with the object of determining this point, the fixed windmill being applied to work which rendered it a matter of indifference in which way the wheel ran. with the prevailing winds from the west it ran in one direction, and with those of next degree of frequency, namely from the east, it turned in the reverse direction. the mill, however, was effective although the breeze might veer several points from either of the locations mentioned. it was found that there were rather less than one-fourth of the points of the compass, the winds from which would bring the wheel to a standstill or cause it to swing ineffectively, but as these were the directions in which the wind least frequently blew it might safely be reckoned that not one-eighth of the possible working hours of a swivel-windmill were really lost in the fixed machine. with the type adapted to the working of a dynamo as already described, it will, in most cases, be convenient to construct two spirals on uprights set in three holes in the ground, forming lines at right angles to each other, but both engaging, by suitable gearing, with the electric current generator situated at the angle. this will be found cheaper than to go to the expense of constructing the mill on a swivel so that it may follow the direction of the wind. at the same time it should be noticed that the adoption of the high speed wind-wheel, consisting of some kind of spiral on a very long axis, may be made effective for improving even the swivel windmill itself, so as to adapt it for electric generation and conservation of power through the medium of the storage battery. supposing that a number of small oblique sails be set upon an axis lying in the direction of the wind, the popular conception of the result of such an arrangement is that the foremost sails would render those behind it almost, if not entirely, useless. the analogy followed in reaching this conclusion is that of the sails of a ship, but, as applied to wind-motors, it is quite misleading, because not more than one-third or one-fourth of the energy of the wind is expended upon the oblique sails of an ordinary wind-wheel. moreover, in the case of a number of such wheels set on a long axis, one behind the other as described, the space within which the shelter of the front sail is operative to keep the wind from driving the next one is exceedingly minute. the elasticity of the air and its frictional inertia when running in the form of wind cause the current to proceed on its course after a very slight check, which in point of time is momentary and in its effects almost infinitesimal. this being the case, and the principal expense attendant upon the construction of ordinary wind-engines being due to the need for providing a large diameter of wind-wheel, with all the attendant complications required to secure such a wheel from risk, it is obvious that as soon as the long axis and the very short sail, or the metallic spiral, have been generally introduced as adjuncts to the dynamo storage battery, an era of cheaper wind-motors will have been entered upon,--in fact, the "little want" of which lord kelvin spoke in will have been supplied. the high speed which the dynamo requires, and the more rapid rate at which windmills constructed on this very economical principle must necessarily run, both mark the two classes of apparatus as being eminently suited for mutual assistance in future usefulness. the anemometer of the "robinson" type, having four little hemispherical cups revolving horizontally, furnishes the first hint of another principle of construction adapted to the generation of electricity. some years ago a professor in one of the scottish universities set up a windmill which was simply an amplified anemometer, and connected it with several of faure's storage batteries for the purpose of furnishing the electric light to his residence. his report regarding his experience with this arrangement showed that the results of the system were quite satisfactory. in this particular type of natural motor the wind-wheel, of course, is permanently set to run no matter from what direction the wind may be blowing. tests instituted with the object of determining the pressure which the wind exerts on the cup of a "robinson" anemometer have shown that when the breeze blows into the concave side of the cup, its effect is rather more than three times as strong as when it blows against the convex side. at any given time the principal part of the work done by a windmill constructed on this principle is being carried out by one cup which has its concave side presented to the wind, while, opposite to it, there is another cup travelling in the opposite direction to that of the wind but having its convex side opposed. the facts that practically only one sail of the mill is operative at any given time, and that even the work which is done by this must be diminished by nearly one-third owing to the opposing "pull" of the cup at the opposite side, no doubt must detract from the merits of such a wind-motor, judged simply on the basis of actual area of sail employed. but when the matter of cost alone is taken as the standard, the advantages are much more evenly balanced than they might at first sight seem to be. the cup-shaped sail may be greatly improved upon for power-generating purposes by adopting a sail having a section not semicircular but triangular in shape, and by extending its length in the vertical direction to a very considerable extent. practically this cheap and efficient wind-motor then becomes a square or hexagonal upright axis of fairly large section, to each side of which is secured a board or a rigid sheet-metal sail projecting beyond the corners. the side of the axis and the projecting portion of the sail then together form the triangular section required. for the sake of safety in time of storm, an opening may be left at the apex of the angle which is closed by a door kept shut through the tension of a spring. when the wind rises to such a speed as to overbalance the force of the spring each door opens and lets the blast pass through. one collateral advantage of this type of windmill is that it may be made to act virtually as its own stand, the only necessity in its erection being that it should have a collar fitting round the topmost bearing, which collar is fastened by four strong steel ropes to stakes securely set in the ground. the dynamo is then placed at the lower bearing and protected from the weather by a metal shield through which the shaft of the axis passes. for pumping, and for other simple purposes apart from the use of the dynamo, a ready application of this form of wind-engine with a minimum of intricacy or expense may be worked out by setting the lower bearing in a round tank of water kept in circular motion by a set of small paddles working horizontally. into the water a vertically-working paddle-wheel dips, carrying on its shaft a crank which directly drives the pump. this simple wind-motor is particularly safe in a storm, because on attaining a high speed it merely "smashes" the water in the tank. solar heat is one of the principal sources of the energy to be derived from the wind. several very determined and ingenious attempts at the utilisation of the heat of sunshine for the driving of a motor have been made during the past century. as a solution of a mechanical and physical puzzle, the arrangement of a large reflector, with a small steam-boiler at the focus of the heat rays thrown by it, is full of interest. yet, when a man like the late john ericsson, who did so much to improve the caloric engine, and the steam-ship as applied to war-like purposes, meets with failure in the attempt to carry such an idea to a commercially successful issue, there is at least _prima facie_ evidence of some obstacle which places the proposed machine at a disadvantage in competition with its rivals. the solar engine, if generally introduced, would be found more intermittent in its action than the windmill--excepting perhaps in a very few localities where there is a cloudless sky throughout the year. the windmill gathers up the power generated by the expansion of the air in passing over long stretches of heated ground, while a solar engine cannot command more of the sun's heat than that which falls upon the reflector or condenser of the engine itself. the latter machine may possibly have a place assigned to it in the industrial economy of the future, but the sum total of the power which it will furnish must always be an insignificant fraction. the wave-power machine, when allied to electric transmission, will, without doubt, supply in a cheap and convenient form a material proportion of the energy required during the twentieth century for industrial purposes. easy and effective transmission is a _sine quâ non_ in this case, just as it is in the utilisation of waterfalls situated far from the busy mart and factory. hardly any natural source of power presents so near an approach to constancy as the ocean billows. shakespeare takes as his emblem of perpetual motion the dancing "waves o' th' sea". but the ocean coasts--where alone natural wave-power is constant--are exactly the localities at which, as a rule, it is the least practicable to build up a manufacturing trade. commerce needs smooth water for the havens offered to its ships, and inasmuch as this requirement is vastly more imperative during the early stages of civilisation than cheap power, the drift of manufacturing centres has been all towards the calm harbours and away from the ocean coasts. but electrical transmission in this connection abolishes space, and can bring to the service of man the power of the thundering wave just as it can that of the roaring torrent or waterfall. the simplest form of wave-motor may be suggested by the force exerted by a ferry boat or dinghy tied up to a pier. the pull exerted by the rope is equal to the inertia of the boat as it falls into the trough of each wave successively, and the amount of strain involved in rough weather may be estimated from the thickness of the rope that is generally found necessary for the security of even very small craft indeed. a similar suggestion is conveyed by the need for elaborate "fenders" to break the force of the shock when a barge is lying alongside of a steamer, or when any other vessel is ranging along a pier or jetty. a buoy of large size, moored in position at a convenient distance from a rock-bound ocean coast, will supply the first idea of a wave-motor on this primary principle as adapted for the generation of power. on the cliff a high derrick is erected. over a pulley or wheel on the top of this there is passed a wire-rope cable fastened on the seaward side to the buoy, and on the landward side to the machinery in the engine-house. the whole arrangement in fact is very similar in appearance to the "poppet-head" and surface buildings that may be seen at any well-equipped mine. the difference in principle, of course, is that while on a mine the engine-house is supplying power to the other side of the derrick, the relations are reversed in the wave-motor, the energy being passed from the sea across into the engine-house. the reciprocating, or backward and forward, movement imparted to the cable by the rising and falling of the buoy now requires to be converted into a force exerted in one direction. in the steam-engine and in other machines of similar type, the problem is simplified by the uniform length of the stroke made by the piston, so that devices such as the crank and eccentric circular discs are readily applicable to the securing of a rotatory motion for a fly-wheel from a reciprocating motion in the cylinders. in the application of wave-power provision must be made for the utilisation of the force derived from movements of _differing lengths_, as well as of _differing characters_, in the force of impact. every movement of the buoy which imparts motion to the pulley on top of the derrick must be converted into an additional impetus to a fly-wheel always running in the same direction. the spur-wheel and ratchet, as at present largely used in machinery, offer a rough and ready means of solving this problem, but two very important improvements must be effected before full advantage can be taken of the principle involved. in the first place it is obvious that if a ratchet runs freely in one direction and only catches on the tooth of the spur-wheel when it is drawn in the other, the power developed and used is concentrated on one stroke, when it might, with greater advantage, be divided between the two; and in the second place the shock occasioned by the striking of the ratchet against the tooth when it just misses catching one of the teeth and is then forced along the whole length of the tooth gathering energy as it goes, must add greatly to the wear and tear of the machinery and to the unevenness of the running. taking the first of these difficulties into consideration it is obvious that by means of a counterbalancing weight, about equal to half that of the buoy, it is possible to cause the wave-power to operate two ratchets, one doing work when the pull is to landwards and the other when it is to seawards. each, however, must be set to catch the teeth of its own separate spur-wheel; and, inasmuch as the direction of the motion in one case is different from what it is in the other, it is necessary that, by means of an intervening toothed wheel, the motion of one of these should be reversed before it is communicated to the fly-wheel. the latter is thus driven always in the same direction, both by the inward and by the outward stroke or pull of the cable from the buoy. perhaps the most convenient development of the system is that in which the spur-wheel is driven by two vertically pendant toothed bands, resembling saws, and of sufficient length to provide for the greatest possible amplitude of movement that could be imparted to them by the motion of the buoy. the teeth are set to engage in those of the spur-wheel, one band on each side, so that the effective stroke in one case is downward, while in the other it is upward. these toothed bands are drawn together at their lower ends by a spring, and they are also kept under downward tension by weights or a powerful spring beneath. the effect of this is that when both are drawn up and down the spur-wheel goes round with a continuous motion, because at every stroke the teeth of one band engage in the wheel and control it, while those of the reversed one (at the other side) slip quite freely. the shock occasioned by the blow of the ratchet on the spur-wheel, or of one tooth upon another, may be reduced almost to vanishing point by multiplying the number of ratchets or toothed bands, and placing the effective ends, which engage in the teeth of the wheel successively, one very slightly in advance of the other. in this way the machine is so arranged that, no matter at what point the stroke imparted by the movement of the buoy may be arrested, there is always one or other of the ratchets or of the teeth which will fall into engagement with the tooth of the spur-wheel, very close to its effective face, and thus the momentum acquired by the one part before it impinges upon the other becomes comparatively small. the limit to which it may be practicable to multiply ratchets or toothed bands will, of course, depend upon the thickness of the spur-wheel, and when this latter has been greatly enlarged, with the object of providing for this feature, it becomes virtually a steel drum having bevelled steps accurately cut longitudinally upon its periphery. the masts of a ship tend to assume a position at right angles to the water-line. when the waves catch the vessel on the beam the greatest degree of pendulous swing is brought about in a series of waves so timed, and of such a length, that the duration of the swing coincides with the period required for one wave to succeed another. the increasing slope of the ship's decks, due to the inertia of this continuous rhythmical motion, often amounts to far more than the angle made by the declivity of the wave as compared with the sea level; and it is, of course, a source of serious danger in the eyes of the mariner. but, for the purposes of the mechanician who desires to secure power from the waves, the problem is not how to avoid a pendulous motion but how to increase it. for each locality in which any large wave-power plant of machinery is to be installed, it will therefore be advisable to study the characteristic length of the wave, which, as observation has proved, is shorter in confined seas than in those fully open to the ocean. it is advisable then to make the beam width of the buoy, no matter how it may be turned, of such a length that when one side is well in the trough of a wave the other must be not far from the crest. practically the best design for such a floating power-generator will be one in which four buoys are placed, each of them at the end of one arm of a cross which has been braced up very firmly. from the angle of intersection projects a vertical mast, also firmly held by stays or guys. the whole must be anchored to the bottom of the sea by attachment to a large cemented block or other heavy weight having a ring let into it, from which is attached a chain of a few links connecting with an upright beam. it is the continuation of the latter above sea-level which forms the mast. on this beam the framework of the buoy must be free to move up and down. at first sight it might seem as if this arrangement rendered nugatory the attempt to take advantage of the rise and fall of the buoy; but it is not so when the relations of the four buoys to one another are considered. although the frame is free to move up and down upon the uprising shaft, still its inclination to the vertical is determined by the direction of the line drawn from a buoy in the trough of a wave to one on the crest. in order to facilitate the free movement, and to render the rocking effect more accurate and free from vibration, sets of wheels running on rails fixed to the beam are of considerable advantage. the rise and fall of the tides render necessary the adoption of some such compensating device as that which has been indicated. of course it would be possible to provide for utilising the force generated by a buoy simply moored direct to a ring at the bottom by means of a common chain cable; but this latter would require to be of a length sufficient to provide for the highest possible wave on the top of the highest tide. then, again, the loose chain at low tide would permit the buoy to drift abroad within a very considerable area of sea surface, and in order to take advantage of the rise and fall on each wave it would be essential to provide at the derrick on the shore end of the wave-power plant very long toothed bands or equivalent devices on a similarly enlarged scale. by providing three or four chains and moorings, meeting in a centre at the buoy itself but fastened to rings secured to weights at the bottom at a considerable distance apart, the lateral movement might, no doubt, be minimised; and for very simple installations this plan, associated with the device of taking a cable from the buoy and turning it several times round a drum on shore, could be used to furnish a convenient source of cheap power. the drum may carry a crank and shaft, which works the spur-wheel and toothed bands as already described, so that no matter at what stage in the revolution of the drum an upward or downward stroke may be stopped, the motion will still be communicated in a continuous rotary form to the fly-wheel. but the beam and sliding frame, with buoys, give the best practical results, especially for large installations. it is in some instances advisable, especially where the depth of the water at a convenient distance from the shore is very considerable, not to provide a single beam reaching the whole distance to the bottom, but to anchor an air-tight tank below the surface and well beneath the depth at which wave disturbance is ever felt. from this submerged tank, which approximately keeps a steady position in all tides and weathers, the upward beam is attached by a ring just as would be done if the tank itself constituted the bottom. one main reason for this arrangement is that the resistance of the beam to the water as it rocks backwards and forwards wastes to some extent the power generated by the force of the waves; and the greater the length of the beam, the longer must be the distance through which it has to travel when the buoys draw it into positions vertical to that of the framework. a thin steel pipe offers less resistance than a wooden beam of equal strength, besides facilitating the use of a simple device for enabling the frame and buoys to slide easily up and down. the generally fatal defect of those inventions which have been designed in the past with the object of utilising wave-power has arisen from the mistake of placing too much of the machinery in the sea. the device of erecting in the water an adjustable reservoir to catch the wave crests and to use the power derived from them as the water escaped through a water-wheel was patented in . nearly twenty years later another scheme was brought out depending upon the working of a large pump fixed far under the surface, and connected with the shore so that, when operated by the rising and falling of floats upon the waves, it would drive a supply of water into an elevated reservoir on shore, from which, on escaping down the cliff, the pressure of the water would be utilised to work a turbine. earlier devices included the building of a mill upon a rocking barge, having weights and pulleys adjusted to run the machinery on board; and also a revolving float so constructed that each successive wave would turn one portion, but the latter would then be held firm by a toothed wheel and ratchet until another impulse would be given to it in the same direction. this plan included certain elements of the simple system already described; but it is obvious that some of its floating parts might with advantage have been removed to the shore end, where they would not only be available for ready inspection and adjustment, but also be out of harm's way in rough weather. different wave-lengths, as already explained, correspond to various periods in the pendulous swing of floating bodies. examples have been cited by mr. vaughan cornish, m. sc., in _knowledge_, nd march, , as follows: "a wave-length of fifty feet corresponds to a period of two and a half seconds, while one of feet corresponds to five and a half seconds. it is mentioned that the swing of the steam-ship _great eastern_ took six seconds." other authorities state that during a storm in the atlantic the velocity of the wave was determined to be thirty-two miles an hour, and that nine or ten waves were included in each mile; thus about five would pass in each minute. but in average weather the number of waves to the mile is considerably larger, say, from fifteen to twenty to the mile; and in nearly calm days about double those numbers. one interesting fact, which gives to wave-power a peculiarly enhanced value as a source of stored wind-power, is that the surface of the ocean--wild as it may at times appear--is not moved by such extremes of agitation as the atmosphere. in a calm it is never so inertly still, and in a storm it is never so far beyond the normal condition in its agitation as is the wind. the ocean surface to some extent operates as the governor of a steam-engine, checking an excess in either direction. in very moderate weather the number of waves to the mile is greatly increased, while their speed is not very much diminished. indeed the rate at which they travel may even be increased. this latter phenomenon generally occurs when long ocean rollers pass out of a region of high wind into one of relative calm, the energy remaining for a long time comparatively constant by reason of the multiplication of short, low waves created out of long, high ones. on all ocean coasts the normal condition of the surface is governed by this law, and it follows that, no matter what the local weather may be at any given time, there is always plenty of power available. an attempt was made by m. c. antoine, after a long series of observations, to establish a general relation between the speed of the wind and that of the waves caused by it, the formulæ being published in the _revue nautique et coloniale_ in . the rule may be taken as correct within certain limits, although in calm weather, when the condition of the ocean surface is almost entirely ruled by distant disturbances, it has but little relevancy. approximately, the velocity of wave transmission is seven times the fourth root of the wind-speed; so that when the latter is a brisk breeze of sixteen miles an hour the waves will be travelling fourteen miles an hour, or very nearly as fast as the wind. when, on the other hand, a light breeze of nine miles an hour is driving the waves, the latter, according to the formula, should run about twelve and a half miles an hour; but, in point of fact, the influence of more distant commotion nearly always interferes with this result. as a matter of experience, the waves on an ocean coast are usually running faster than the wind, and, being so much more numerous in calm than they are in rough weather, they maintain comparatively a uniform sum total of energy. it is obvious that, so far as practical purposes are concerned, three waves of an available height of three feet each are as effective as one of nine feet. if the state of the weather be such that the average wave length is feet there will be exactly thirty waves to the mile, and if the speed be twelve miles an hour--that is to say, if an expanse of twelve miles of waves pass a given point hourly--then waves will pass every sixty minutes, or six every minute. in the wave-power plant as described, each buoy of one hundred tons displacement when raised and depressed, say, three feet by every wave will thus be capable of giving power equal to three times , or , foot-tons per minute. the unit of nominal horse-power being , foot-pounds or about fifteen foot-tons per minute, it is evident that each buoy, at its maximum, would be capable of giving about horse-power. supposing that half of the possible energy were exerted at the forward and half at the backward stroke and that each buoy were always in position to exert its full power upon the uprising shaft without deduction, the total effective duty of a machine such as has been described would be horse-power. in practice, however, the available duty would probably, according to minor circumstances, be rather more or rather less than horse-power. chapter iii. storage of power. the three principal forms of stored power which are now in sight above the horizon of the industrial outlook are the electric storage battery, compressed air, and calcium-carbide. the first of these has come largely into use owing to the demand for a regulated and stored supply of electricity available for lighting purposes. indeed the storage battery has practically rendered safe the wide introduction of electric lighting, because a number of cells, when once charged, are always available as a reserve in case of any failure in the power or in the generators at any central station; and also because, by means of the storage cells or "accumulators," the amount of available electrical energy can be subdivided into different and subordinate circuits, thus obviating the necessity for the employment of currents of very high voltage and eluding the only imperfectly-solved problem of dividing a current traversing a wire as conveniently as lighting gas is divided by taking small pipes off from the gas mains. compressed air for the storage of power has hitherto been best appreciated in mining operations, one of the main reasons for this being that the liberated air itself--apart from the power which it conveyed and stored--has been so great a boon to the miner working in ill-ventilated stopes and drives. the cooling effects of the expansion, after close compression, are also very grateful to men labouring hard at very great depths, where the heat from the country rock would become, in the absence of such artificial refrigeration, almost overpowering. for underground railway traffic exactly the same recommendations have, at one period during the fourth quarter of the nineteenth century, given an adventitious stimulus to the use of compressed air. yet it is now undoubted that, even in deep mining, the engineer's best policy is to adopt different methods for the conveyance and storage of power on the one hand, and for the ventilation of the workings on the other. few temptations are more illusory in the course of industrial progress than those presented by that class of inventions which aim at "killing two birds with one stone". if one object be successfully accomplished it almost invariably happens that the other is indifferently carried out; but the most frequent result is that both of them suffer in the attempt to adapt machinery to irreconcilable purposes. the electric rock-drill is now winning its way into the mines which are ventilated with comparative ease as well as into those which are more difficult to supply with air. it is plain, therefore, that on its merits as a conveyer and storer of power the electric current is preferable to compressed air. the heat that is generated and then dissipated in the compression of any gas for such a purpose represents a very serious loss of power; and it is altogether an insufficient excuse to point to the compensation of coolness being secured from the expansion. fans driven by electric motors already offer a better solution of the ventilation difficulty, and the advantages on this side are certain to increase rather than to diminish during the next few years. the electric rock-drill, which can already hold its own with that driven by compressed air, is therefore bound to gain ground in the future. this is a type and indication of what will happen all along the industrial line, the electric current taking the place of the majority of other means adopted for the transmission of power. even in workshops--where it is important to have a wide distribution of power and each man must be able to turn on a supply of it to his bench at any moment--shafting is being displaced by electric cables for the conveyance of power to numerous small motors. the loss of power in this system has already been reduced to less than that which occurs with shafting, unless under the most favourable circumstances; and in places where the works are necessarily distributed over a considerable area the advantage is so pronounced that hardly any factories of that kind will be erected ten years hence without resort being had to electricity, and small motors as the means of distributing the requisite supplies of power to the spots where they are needed. it was a significant fact that at the paris exposition of the electric system of distribution was adopted. in regard to compressed air, however, it seems practically certain that, notwithstanding its inferiority to electric storage of power, it is applicable to so many kinds of small and cheap installations that, on the whole, its area of usefulness, instead of being restricted, will be largely increased in the near future. there will be an advance all along the line; and although electric storage will far outstrip compressed air for the purposes of the large manufacturer, the air reservoir will prove highly useful in isolated situations, and particularly for agricultural work. for example, as an adjunct to the ordinary rural windmill for pumping water, it will prove much more handy and effective than the system at present in vogue of keeping large tanks on hand for the purpose of ensuring a supply of water during periods of calm weather. regarding a tank of water elevated above the ground and filled from a well as representing so much stored energy, and also comparing this with an equal bulk of air compressed to about pounds pressure to the square inch, it would be easy to show that--unless the water has been pumped from a very deep well--the power which its elevation indicates must be only a small fraction of that enclosed in the air reservoir. it will be one great point in favour of compressed air, as a form of stored energy for the special purpose of pumping, that by making a continuous small flow of air take the place of the water at the lowest level in the upward pipe, it is possible to cause it to do the pumping without the intervention of any motor. one means of effecting this may be simply indicated. the air under pressure is admitted from a very small air pipe and the bubbles, as they rise, fill the hollow of an inverted iron cup rising and falling on a bearing like a hinge. above and beneath the chamber containing this cup are valves opening upwards and similar to those of an ordinary force or suction pump. the cup must be weighted with adjustable weights so that it will not rise until quite full of air. when that point is reached the stroke is completed, the air having driven upwards a quantity of water of equal bulk with itself, and, as the cup falls again by its own weight, the vacuum caused by the air escaping upwards through the pipe is filled by an inrush of water through the lower valve. the function of the upper valve, at that time, is to keep the water in the pipe from falling when the pressure on the column is removed. the expansive power of the air enables it to do more lifting at the upper than at the lower level, so that a larger diameter of pipe can be used at the former place. cheap motors working on the same principle--that is to say through the upward escape of compressed air, gas or vapour filling a cup and operating it by its buoyancy, or turning a wheel in a similar manner--will doubtless be a feature in the machine work of the future; and for motors of this description it is obvious that compressed air will be very useful as the form of power-storage. excepting under very special conditions, steam is not available for such a purpose, seeing that it condenses long before it has risen any material distance in a column of cold water. "the present accumulator," remarked prof. sylvanus p. thompson in the year , referring to the faure storage batteries then in use, "probably bears as much resemblance to the future accumulator as a glass bell-jar used in chemical experiments for holding gas does to the gasometer of a city gasworks, or james watt's first model steam-engine does to the engines of an atlantic steamer." when faure, having in improved upon the storage battery of planté, sent his four-cell battery from paris to glasgow, carrying in it stored electrical energy, it was found to contain power equal to close upon a million foot-pounds, which is about the work done by a horse-power during the space of half an hour. this battery weighed very nearly lb. it nevertheless represented an immense forward step in the problem of compressing a given quantity of potential power into a small weight of accumulator. the progress made during less than twenty years to the end of the century may be estimated from the conditions laid down by the automobile club of paris for the competitive test of accumulators applicable to auto-car purposes in . it was stipulated that five cells, weighing in all lb., should give out ampere-hours of electric intensity; and that at the conclusion of the test there should remain a voltage of · volt per cell. very great improvements in the construction of electric accumulators are to be looked for in the near future. hitherto the average duration of the life of a storage cell has not been more than about two years; and where impurities have been present in the sulphuric acid, or in the litharge or "minium" employed, the term of durability has been still further shortened. it must be remembered that while the principal chemical and electrical action in the cell is a circular one,--that is to say, the plates and liquids get back to the original condition from which they started when beginning work in a given period,--there is also a progressive minor action depending upon the impurities that may be present. such a reagent, for instance, as nitric acid has an extremely injurious effect upon the plates. during the first decade after planté and faure had made their original discoveries, the main drawback to the advancement of the electric accumulator for the storage of power owed its existence to the lack of precise knowledge, among those placed in charge of storage batteries, as to the destructive effects of impurities in the cells. it is, however, now the rule that all acids and all samples of water used for the purpose must be carefully tested before adoption, and this practice, in itself, has greatly prolonged the average life of the accumulator cell. the era of the large electric accumulator of the kind foreshadowed by prof. sylvanus p. thompson has not yet arrived, the simple reason being that electric power storage--apart from the special purposes of the subdivision and transmission for lighting--has not yet been tried on a large scale. for the regulation and graduation of power it is exceedingly handy to be able to "switch-on" a number of small accumulator cells for any particular purpose; and, of course, the degree of control held in the hands of the engineer must depend largely on the smallness of each individual cell, and the number which he has at command. this fact of itself tends to keep down the size of the storage cell which is most popular. but when power storage by means of the electric accumulator really begins in earnest the cells will attain to what would at present be regarded as mammoth proportions; and the special purpose aimed at in each instance of power installation will be the securing of continuity in the working of a machine depending upon some intermittent natural force. windmills are especially marked out as the engines which will be used to put electrical energy into the accumulators. from these latter again the power will be given out and conveyed to a distance continuously. high ridges and eminences of all kinds will in the future be selected as the sites of wind-power and accumulator plants. in the eighteenth century, when the corn from the wheat-field required to be ground into flour by the agency of wind-power, it was customary to build the mill on the top of some high hill and to cart all the material laboriously to the eminence. in the installations of the future the power will be brought to the material rather than the material to the power. from the ranges or mountain peaks, and also from smaller hills, will radiate electrical power-nerves branching out into network on the plains and supplying power for almost every purpose to which man applies physical force or electro-chemical energy. the gas-engine during the twentieth century will vigorously dispute the field against electrical storage; and its success in the struggle--so far as regards its own particular province--will be enhanced owing to the fact that, in some respects, it will be able to command the services of electricity as its handmaid. gas-engines are already very largely used as the actuators of electric lighting machinery. but in the developments which are now foreshadowed by the advent of acetylene gas the relation will be reversed. in other words, the gas-engine will owe its supply of cheap fuel to the electric current derived at small expense from natural sources of power. calcium carbide, by means of which acetylene gas is obtained as a product from water, becomes in this view stored power. the marvellously cheap "water-gas" which is made through a jet of steam impinging upon incandescent carbons or upon other suitable glowing hot materials will, no doubt, for a long time command the market after the date at which coal-gas for the generation of power has been partially superseded. but it seems exceedingly probable that a compromise will ultimately be effected between the methods adopted for making water-gas and calcium carbide respectively, the electric current being employed to keep the carbons incandescent. when power is to be sold in concrete form it will be made up as calcium carbide, so that it can be conveyed to any place where it is required without the assistance of either pipes or wires. but when the laying of the latter is practicable--as it will be in the majority of instances--the gas for an engine will be obtainable without the need for forcing lime to combine with carbon as in calcium carbide. petroleum oil is estimated to supply power at just one-third the price of acetylene gas made with calcium carbide at a price of £ per ton. this calculation was drawn up before the occurrence of the material rise in the price of "petrol" in the last year of the nineteenth century; while, concurrently, the price of calcium carbide was falling. a similar process will, on the average, be maintained throughout each decade; and, as larger plants, with cheaper natural sources of energy, are brought into requisition, the costs of power, as obtained from oil and from acetylene gas, will more and more closely approximate, until, in course of time, they will be about equal; after which, no doubt, the relative positions will be reversed, although not perhaps in the same ratio. time is all on the side of the agent which depends for its cheapness of production on the utilisation of any natural source of power which is free of all cost save interest, wear and tear, and supervision. even the steam-engine itself is not exempt from the operation of the general law placing the growing advantage on the side of power that is obtainable gratis. one cubic inch of water converted into steam and at boiling point will raise a ton weight to the height of one foot; and the quantity of coal of good quality needed for the transformation of the water is very small. one pound of good coal will evaporate nine pounds of water, equal to about cubic inches, this doing foot-tons of work. but niagara performs the same amount of work at infinitely less cost. however small any quantity may be, its ratio to nothing is infinity. it has been the custom during the nineteenth century to institute comparisons between the marvellous economy of steam power and the expensive wastefulness of human muscular effort. for instance, the full day's work of an eastern porter, specially trained to carry heavy weights, will generally amount to the removal of a load of from three to five hundred-weight for a distance of one mile; but such a labourer in the course of a long day has only expended as much power as would be stored up in about five ounces of coal. still the fact remains that one of the greatest problems of the future is that which concerns the reduction in the cost of power. hundreds of millions of the human race pass lives of a kind of dull monotonous toil which develops only the muscular, at the expense of the higher, faculties of the body; they are almost entirely cut off from social intercourse with their fellow-men, and they sink prematurely into decrepitude simply by reason of the lack of a cheap and abundant supply of mechanical power, ready at hand wherever it is wanted. scores of "enterprises of great pith and moment" in the industrial advancement of the world have to be abandoned by reason of the same lack. in mining, in agriculture, in transport and in manufacture the thing that is needful to convert the "human machine" into a more or less intelligent brainworker is cheaper power. all the technical education in the world will not avail to raise the labourer in the intellectual scale if his daily work be only such as a horse or an engine might perform. the transmission of power through the medium of the electric current will naturally attain its first great development in the neighbourhoods of large waterfalls such as niagara. when the manufacturers within a short radius of the source of power in each case have begun to fully reap the benefit due to cheap power, competition will assert itself in many different ways. the values of real property will rise, and population will tend to become congested within the localities' served. it will be found, however, that facilities for shipment will to a large extent perpetuate the advantage at present held by manufactories situated on ports and harbours; and this, of course, will apply with peculiar force to the cases of articles of considerable bulk. where a very great deal of power is needed for the making of an article or material of comparatively small weight and bulk proportioned to its value--such for instance as calcium carbide or aluminium--the immediate vicinity of the source of natural power will offer superlative inducements. but an immense number of things lie between the domains of these two classes, and for the economical manufacture of these it is imperative that both cheap power and low wharfage rates should be obtainable. an increasingly intense demand must thus spring up for systems of long distance transmission, and very high voltage will be adopted as the means of diminishing the loss of power due to leakage from the cables. similarly the "polyphase" system--which is eminently adapted to installations of the nature indicated--must demand increasing attention. taking a concrete example, mention may be made of the effects to be expected from the proposed scheme for diverting some of the headwaters of the tay and its lakes from the eastern to the western shores of scotland and establishing at loch leven--the western inlet, not the inland lake of that name--a seaport town devoted to manufacturing purposes requiring very cheap supplies of power. it is obvious that the owners of mills in and around glasgow, and only forty or fifty miles distant, will make the most strenuous exertions to enable them to secure a similar advantage. it is already claimed that with the use of currents of high voltage for carrying the power, and "step-down transformers" converting these into a suitable medium for the driving of machinery, a fairly economical transmission can be ensured along a distance of miles. it therefore seems plain that the natural forces derived from such sources as waterfalls can safely be reckoned upon as friends rather than as foes of the vested interests of all the great cities of the united kingdom. the possibilities of long distance transmission are greatly enhanced by the very recent discovery that a cable carrying a current of high voltage can be most effectually insulated by encasing it in the midst of a tube filled with wet sawdust and kept at a low temperature, preferably at the freezing point of water. wireless transmission of a small amount of power has been proved to be experimentally possible. in the rarefied atmosphere at a height of five or ten miles from the earth's surface, electric discharges of very high voltage are conveyed without any other conducting medium than that of the air. by sending up balloons, carrying suspended wires, the positions of despatch and of receipt can be so elevated that the resistance of the atmosphere can be almost indefinitely diminished. in this way small motors have been worked by discharges generated at considerable distances, and absolutely without the existence of any connection by metallic conductors. possibilities of the exportation of power from suitable stations--such as the neighbourhoods of waterfalls--and its transmission for distances of hundreds or even thousands of miles have been spoken of in relation to the industrial prospects of the twentieth century. comparing any such hypothetical system with that of sending power along good metallic conductors, there is at once apparent a very serious objection in the needless dispersion of energy throughout space in every direction. if a power generator by wireless transmission, without any metallic connection, can work one motor at a distance of, say, , miles, then it can also operate millions of similar possible motors situated at the same distance; and by far the greater part of its electro-motive force must be wasted in upward dispersion. the analogy of the wireless transmitter of intelligence may be misleading if applied to the question of power. the practicability of wireless telegraphy depends upon the marvellous susceptibility of the "coherer," which enables it to respond to an impulse almost infinitesimally small, certainly very much smaller than that despatched by the generator from the receiving station. from this it follows, as already stated, that the analogy of apparatus designed merely for the despatch of intelligence by signalling cannot safely be applied to the case of the transmission of energy. making all due allowances for the prospects of advance in minimising the resistance of the atmosphere, it must nevertheless be remembered that any wireless system will be called upon to compete with improved means of conveying the electric current along metallic circuits. electrical science, moreover, is only at the commencement of its work in economising the cost of power-cables. the invention by which one wire can be used to convey the return current of two cables very much larger in sectional area is only one instance in point. the two major cables carry currents running in opposite directions, and as these currents are both caused to return along the third and smaller wire their electro-motive forces balance one another, with the result that the return wire needs only to carry a small difference-current. the return wire, in fact, is analogous to the banking clearing house, which deals with balances only, and which therefore can sometimes adjust business to the value of many millions with payments of only a few thousands. later on it may fairly be expected that duplicate and quadruplicate telegraphy will find its counterpart in systems by which different series of electrical impulses of high voltage will run along a wire, the one alternating with the other and each series filling up the gaps left between the others. chapter iv. artificial power. the steam-turbine is the most clearly visible of the revolutionary agencies in motors using the artificial sources of power. in the first attempts to introduce the principle the false analogy of the water-turbine gave rise to much waste of inventive energy and of money; but the more recent and more distinctly successful types of machine have been constructed with a clear understanding that the windmill is the true precursor of the steam-turbine. it is clearly perceived that, although it may be convenient and even essential to reduce the arms to pigmy dimensions and to enclose them in a tube, still the general principle of the machine must resemble that of a number of wind motors all running on the same shaft. it has been proved, moreover, that this multiplicity of minute wheels and arms has a very distinct advantage in that it renders possible the utilisation of the expansive power of steam. the first impact is small in area but intense in force, while those arms which receive the expanded steam further on are larger in size as suited to making the best use of a weaker force distributed over a greater amount of space. the enormous speed at which steam under heavy pressure rushes out of an orifice was not duly appreciated by the first experimenters in this direction. to obtain the best results in utilising the power from escaping steam there must be a certain definite proportion between the speed of the vapour and that of the vane or arm against which it strikes. in other words, the latter must not "smash" the jet, but must run along with it. in the case of the windmill the ratio has been stated approximately by the generalisation that the velocity of the tips of the sails is about two and a half times that of the wind. this refers to the old style of windmill as used for grinding corn. the steam turbine must, therefore, be essentially a motor of very great initial speed; and the efforts of recent inventors have been wisely directed in the first instance to the object of applying it to those purposes for which machinery could be coupled up to the motor with little, if any, necessity for slowing down the motion through such appliances as belting, toothed wheels, or other forms of intermediate gearing. the dynamo for electric lighting naturally first suggested itself; but even in this application it was found necessary to adopt a rate of speed considerably lower than that which the steam imparts to the turbine; and, unfortunately, it is exactly in the arrangement of the gear for the first slowing-down that the main difficulty comes in. nearly parallel is the case of the cream separator, to which the steam-turbine principle has been applied with a certain degree of success. by means of fine flexible steel shafts running in bearings swathed in oil it has been found possible to utilise the comparatively feeble force of a small steam jet operating at immense speed to produce one of much slower rate but enormously greater strength. some success has been achieved also in using the principle not only for cream separators, which require a comparatively high velocity, but for other purposes connected with the rural and manufacturing industries. an immense forward stride, however, was made when the idea was first conceived of a steam-turbine and a water-turbine being fixed on the same shaft and the latter being used for the propulsion of a vessel at sea. in this case it is obvious that, by a suitable adjustment of the pitch of screw adopted in both cases, a nice mathematical agreement between the vapour power and the liquid application of that power can be ensured. all previous records of speed have been eclipsed by the turbine-driven steamers engined on this principle. through the abolition of the principal causes of excessive vibration--which renders dangerous the enlargement of marine reciprocating engines beyond a certain size--the final limit of possible speed has been indefinitely extended. the comfort of the passenger, equally with the safety of the hull, demands the diminution of the vibration nuisance in modern steamships, and whether the first attempts to cater for the need by turbine-engines be fully successful or not, there is no doubt whatever that the fast mail packets of the future will be driven by steam-engines constructed on a system in which the turbine principle will form an important part. further applications will soon follow. it is clear that if the steam-turbine can be advantageously used for the driving of a vessel through the water, then, conversely, it can be similarly applied to the creation of a current of water or of any other suitable liquid. this liquid-current, again, is applicable to the driving of machinery at any rate that may be desired. in this view the slowing-down process, which involves elaborate and delicate machinery when accomplished in the purely mechanical method, can be much more economically effected through the friction of fluid particles. one method of achieving this object is an arrangement in which the escaping steam drives a turbine-shaft running through a long tube and passing into the water in a circular tank, in which, again, the shaft carries a spiral or turbine screw for propelling the water. the arrangement, it will be seen, is strictly analogous to that of the steam-turbine as used in marine propulsion, the shaft passing through the side of the tank just as it does through the stern of the vessel. one essential point, however, is that the line of the shaft must not pass through the centre of the circular tank, but must form the chord of an arc, so that when the water is driven against the side by the revolution of the screw it acts like a tangential jet. practically the water is thus kept in motion just as it would be if a hose with a strong jet of water were inserted and caused to play at an obtuse angle against the inner side. motion having been imparted to the fluid in the tank, a simple device such as a paddle-wheel immersed at its lower end, may be adopted for taking up the power and passing it on to the machinery required to be actuated. by setting both the shaft carrying the vanes for the steam-turbine and the screw for the propulsion of the water at a downward inclination it becomes practicable to drive the fluid without requiring any hole in the tank; and in this case the latter may be shaped in annular form and pivoted so that it becomes a horizontal fly-wheel. obstructing projections on the inside periphery of the annular tank assist the water to carry the latter along with it in its circular motion. for small steam motors, particularly for agricultural and domestic purposes, the turbine principle is destined to render services of the utmost importance. the prospect of its extremely economical construction depends largely upon the fact that, with the exception of two or three very small bearings carrying narrow shafts, it contains no parts demanding the same fine finish as does the cylinder of a reciprocating engine. it solves in a very simple manner the much-vexed problem of the rotary engine, upon which so much ingenuity has been fruitlessly exercised. the steam-turbine also has shown that, for taking advantage of the generation and the expansive power of steam, there is no absolute necessity for including a steam-tight chamber with moving parts in the machine. for very small motors suitable for working fans and working other household appliances, the use of a jet of steam, applied directly to drive a small annular fly-wheel filled with mercury--without the intervention of any turbine--will no doubt prove handy. but in the economy of the future such appliances will take the place of electrical machinery only in exceptional situations. one promising use of the turbine or steam-jet--used to propel a fly-wheel filled with liquid as described--has for its object the supply of the electric light in country houses. in this case the fly-wheel is fitted, on its lower side, to act as the armature of a dynamo, and the magnets are placed horizontally around it. the full effective power from a jet of steam is not communicated to a dynamo for electric lighting or other purposes unless there be a definite ratio between the speeds of the turbine and of the armature respectively. this may be conveniently provided for, with more precision and in a less elaborate way than that which has just been described, if the steam jet be made to drive a vertically pendant turbine, the lower extremity of which, carrying very small horizontal paddles, must be inserted into the centre of a circular tank. the principle upon which the reduction of speed necessary for the dynamo is then effected depends upon the fact that in a whirlpool the liquid near the centre runs nearly as fast as that on the outer periphery, and therefore--the circles being so very much smaller--the number of revolutions effected in a given time is much greater. thus a steam jet turning a pendant turbine--dipping into the middle of the whirlpool and carrying paddles--at an enormously high speed may be made to impart motion to the water in a circular tank (or, if desired, to the tank itself) at a very much slower rate; the amount of the reduction, of course, depending mainly on the ratio between the diameter of the tank and the length of the small paddles at the centre setting the liquid in motion. for special purposes it is best to substitute a spherical for an ordinary circular tank and the size may be greatly diminished by using mercury instead of water. the sphere is complete, excepting for a small aperture at the top for the admission of the steel shaft of the steam-driven turbine. no matter how high may be the speed, the liquid cannot be thrown out from a spherical revolving receptacle constructed in this way. moreover, the mercury acts not only as a transmitter of the power from the turbine to the purpose for which it is wanted, but also as a governor. whenever the speed becomes so great as to throw the liquid entirely into the sides of the sphere--so that the shaft and paddles are running free of contact with it in the middle--the machine slows down, and it cannot again attain full speed until the same conditions recur. the rate of speed which may be worked up to as a maximum is determined by the position of the paddle-wheel, which is adjustable and floats upon the liquid although controlled in its circular motion by the shaft which passes through a square aperture in it and also a sleeve extending upward from it. the duty of the latter is to economise steam by cutting off the jet as soon as, by its rapidity of motion, the paddle-wheel has thrown the mercury to the sides to such an extent as to sink to a certain level in the centre. cheap motors coupled with cheap dynamos will, in the twentieth century, go far towards lightening the labours of millions whose toil is at present far too much of a mere mechanical nature. the dynamo itself, however, requires to be greatly reduced in first cost. particularly it is necessary that the expense involved in drawing the wire, insulating it, and winding machines with it, should be diminished. this will no doubt be partly accomplished by the electrolytic producers of copper when once they get properly started on methods of depositing thin strips or wires of tough copper on to sheets of insulating material for wrapping round the magnets and other effective parts intended for dynamos. there is no fundamental reason which forbids that when electro deposition is resorted to for the recovery of a metal from its ore it should be straightway converted to the shape and to the purpose for which it is ultimately intended. this consideration has presented itself to the minds of some of the manufacturers of aluminium, who make many articles intended for household use electrolytically; and it must affect many other trades which are concerned in the output and in the working-up of metals readily susceptible of deposition--more particularly such as copper. the familiar aneroid barometer furnishes a hint for another convenient form of small steam-engine. in seeking to cheapen machinery of this class it is of the utmost importance that the necessity for boring out cylinders and for planing and other expensive work should be avoided. in the aneroid barometer a shallow circular box is fitted with a cover, which is corrugated in concentric circles, and the pressure of the superincumbent air is caused to depress the centre of this cover through the device of partially exhausting the box of air and thus diminishing the internal resistance. to the slightly moving middle part of the cover is affixed a lever which actuates, after some intermediate action, the hand which moves on the dial to indicate, by its record of variations in the weight of the atmosphere, what the prospect of the weather may be. in the aneroid form of the steam-engine the cylinder is immensely widened and flattened, and the broad circular lid, with its spiral corrugations, takes the place of the piston. the rod, which acts virtually as a piston-rod, is hollow, and it works into a bearing which permits the steam to escape when the extreme point of the stroke has been reached into a separate condensing chamber kept cool with water. the boiler itself, with corrugated top, may take the place of the cylinder. in some respects this little machine represents a retrograde movement, even from watt's original engine with its separate condenser; but its extreme economy of first cost recommends it to poor producers. in the near future no country homestead will be without its power installation of one kind or another, and there is room for many types of cheap motors. a motor like the steam-turbine is evidently the forerunner of other engines designed to utilise the force of an emission jet of vapour or gas. there are very many processes in which gases generated by chemical combinations are permitted to escape without performing any services, not even that of giving up the energy which they may be made to store up when held in compression in a closed vessel. the reciprocating forms found suitable for steam and gas engines are hardly adaptable for experiments in the direction of economising this source of power, one fatal objection in the majority of cases being the corrosive effects of the gases generated upon the insides of cylinders and other working parts. as soon as the force of the emission jet can be applied as a factor in giving motive power, the fact that no close-fitting parts are required for the places upon which the line of force impinges will alter the conditions of the whole problem. in the centrifugal sand pump, as now largely used for raising silt from rivers and harbours, the serious corrosive action of the jet of sand and water upon the inside of the pump has been successfully overcome by facing the metal with indiarubber; but nothing of the kind could have been done if the working of the apparatus had depended on the motion of close-fitting parts, as in the ordinary suction or lift pump. as an instance of the class of work for which gaseous jets, for driving turbines or similar forms of motor, may perform useful services the case of farm-made superphosphate of lime may be cited. by subjecting bones to the action of sulphuric acid the farmer may manufacture his own phosphatic manures for the enrichment of his land. but the carbonic dioxide and other gases generated as the result of the operation are wasted. therefore it at present pays better to carry the bones to the sulphuric acid than to reverse the procedure by conveying the acid to the farm, where the bones are a by-product. so bulky are the latter, however, that serious waste of labour is involved in transporting them for long distances. calculations made out by the experts of various state agricultural stations show that, as a general rule, it is now cheaper for the farmer to buy his superphosphates ready made than to make them on his farm. the difference in some cases, however, is not great; and only a comparative trifle would be needed in order to turn the balance. this may probably be found in the economic value of the service rendered by a turbine-engine or other device for utilising the expansive power of the gases which are driven from the constituents of the bones by the action of the sulphuric acid. for pumping water and other ordinary farm operations the chemical gas-engine will prove very handy; and the great point in its favour will be that instead of useless cinders the refuse from it will consist of the most valuable compost with which the farmer can dress the soil. enamelled iron will be employed for the troughs in which the bones and acid will be mixed, and a cover similar to that placed over a "papin's digester" will be clamped to the rim all round, the gases being liberated only in the form of a jet used for driving machinery. for very small motors, applicable specially to domestic purposes such as ventilation, there is one source of power which, in all places within the reticulation areas of waterworks, may be had practically for nothing. probably when the owners of water-supply works realise that they have command of something which is of commercial value, although hitherto unnoticed, they will arrange to sell not only the water which they supply, but also the power which can be generated by its escape when utilised and by the variations in the pressure from hour to hour and even from minute to minute. the latter, for such purposes as ventilation, for instance, will no doubt come to the front sooner than the intermittent power now wasted by the outflowing of water--a power which is comparatively too small an item in most cases to compensate for the outlay and trouble of arranging for the storage of energy. but in the case of the variation in the pressure, without any escape of water at all, no such disability appears. experiments conducted in several of the larger cities of england with various types of water meters--which are really motors on a small scale--have proved the practicability of obtaining a source of constant power from what may be termed the ebb and the flow of pressure within the pipes of a water supply system. at every hour of the day there is a marked variation in the quantity of water that is being drawn away by consumers, and consequently a rise and fall in the degree of pressure recorded by the meter. in an apparatus for converting the power derivable from this source to useful purposes something on a very small scale analogous to that which has already been described in connection with utilising the rise and fall of a wave will be found serviceable. a small spur-wheel is gripped on two sides by two metal laths, with edges serrated like those of saws, and held against the wheel by gentle pressure. every movement of the two saws--whether backwards or forwards--is then responded to by a continuous circular motion of the wheel, with the sole exception of those movements which may be too small in extent to include even as much as a single tooth of the wheel. on this account it is important that the teeth should be made as numerous as possible consistently with the amount of pressure which they may have to bear. resort may be had to the principle of the aneroid barometer in order to secure from the water within the pipe-system the energy by which these saw-like bands are driven up and down with reciprocal motion. a very shallow circular tank in the shape of a watch is in communication with the water in the pipes, and its top or covering is composed of a concentrically-corrugated sheet of finely tempered steel. at the centre of this is fixed the guide which pushes and pulls the saw-like laths. every rise and fall in the pressure of the water now effects a movement of the spur-wheel, and the latter may conveniently be connected with the strong spring of a clockwork attachment, so that the water pressure is really used for winding up a clockwork ventilating-fan. in the making of cheap steam and gas engines, as well as in machine work generally, rapid progress will be made when the possibilities of producing hard and smooth wearing surfaces without the need for cutting and filing rough-cast metal have been fully investigated. many parts of machinery will be electro-deposited--like the small articles already mentioned--in aluminium or hard copper at the metallurgical works where ore is being treated for the recovery of metal, or even at the mines themselves. side by side with this movement there will be one for developing the system of stamping mild steel and then tempering it. at the same time also the behaviour of various metals and alloys, not only in the cold state but also at the critical point between melting and solidification, will be much more carefully studied so as to take advantage of every means whereby accurately shaped articles may be made and finished in the casting. it has been found, for example, that certain kinds of type metal, if placed under very heavy pressure at the moment when passing from the liquid to the solid condition, not only take the exact form of the mould in which they are placed, but become extremely hard by comparison with the same alloy if permitted to solidify without pressure. the example of the cheap watch industry may be cited to convey an idea of the immensely important revolution which will take place in the production of both small and large prime-motors when all the possibilities of electrotyping, casting, and stamping the various wearing parts true to shape and size have been fully exploited. an accurate timekeeper is now practically within the reach of all; and in the twentieth century no one who requires a small prime motor to do the rough work about home or farm will be compelled to do without it by reason of poverty--unless, perhaps, he is absolutely destitute and a fit subject for public charity. many domestic industries which were crushed out of existence during the early part of the nineteenth century will therefore be resuscitated. the dear steam-engine created the factory system and brought the operatives to live close together in long rows of unsightly dwellings, but the cheap engine, in conjunction with the motor driven by transmitted electricity, will give to the working people comparative freedom again to live where they please, and to enjoy the legitimate pleasures both of town and of country. chapter v. road and rail. the existing keen motor-car rivalry presents one of the most interesting and instructive mechanical problems which are left still unsolved by the close of the nineteenth century. the question to be determined is not so much whether road locomotion by means of mechanical power is practicable and useful, for, of course, that point has been settled long ago; indeed it would have been recognised as settled years before had it not been for the crass legislation of a quarter of a century since which deliberately drove the first steam-motors off the road in order to ensure the undisturbed supremacy of horse traffic. the real point at issue is whether a motor can be made which shall furnish power for purposes of road locomotion as cheaply and conveniently as is already done for stationary purposes. horse traction, although extremely dear, possesses one qualification which until the present day has enabled it to outdistance its mechanical competitors upon ordinary roads. this is its power of adapting itself, by special effort, to the exigencies caused by the varying nature of the road. watch a team of horses pulling a waggon along an undulating highway, with level stretches of easy going and here and there a decline or a steep hill. there is a continual adjustment of the strain which each animal puts upon itself according to the character of the difficulties which must be surmounted, the effort varying from nothing at all--when going down a gentle decline--up to the almost desperate jerk with which the vehicle is taken over some stony part right on the brow of an eminence. the whip cracks and by threats and encouragements the driver induces each horse to put forth, for one brief moment, an effort which could not be sustained for many minutes save at the peril of utter exhaustion. when the unit of nominal horse-power was fixed at , foot-pounds per minute the work contemplated in the arbitrary standard was supposed to be such as a horse could go on performing for several hours. it was, of course, well recognised that any good, upstanding horse, if urged to a special effort, could perform several times the indicated amount of work in a minute. nevertheless the habit of reckoning steam-power in terms of a unit drawn from the analogy of the horse undoubtedly tended for many years to obscure the essential difference between the natures of the two sources of power. railroads were built with the object of rendering as uniform as possible the amount of power required to transport a given weight of goods or passengers over a specified distance; and consequently the application of the steam-engine to traffic conducted on the railway line was a success. many inventors at once jumped to the conclusion that, by making some fixed allowance for the greater roughness of an ordinary road, they would be able to construct a steam-traction engine that would suit exactly for road traffic. in a rough and rudimentary way an attempt to provide for the special effort required at steep or stony places was made by the introduction of a kind of fly-wheel of extraordinary weight proportionate to the size of the engine; and the same object was aimed at by increasing the power of the engine to somewhere near the limit of the possible special requirements. the consequence was the evolution of an immensely ponderous and wasteful machine, which for some years only held its ground within the domain of the heavy work of roadmaking. as a means of road traction the steam-engine was for half a century almost entirely discomfited and routed by horse-power, partly owing to this mechanical defect and partly, as we have seen, through legislative partisanship. the explosive type of engine was next called into requisition to do battle against the living competitor of the engineer's handiwork. petroleum and alcohol, when volatilised and mixed with air in due proportion, form explosive mixtures which are much more nearly instantaneous in their action than an elastic vapour like steam held under pressure in a boiler, and liberated to perform its work by comparatively slow expansion. the petroleum engine, as applied to the automobile, does its work in a series of jerks which provide for the unequal degrees of power required to cope with the unevenness of a road. as against this, however, there are certain grave defects, due mainly to the use of highly inflammable oils vapourised at high temperatures; and these have impressed a large proportion of engineers with a belief that, in the long run, either electricity or steam will win the day. storage batteries are well adapted for meeting the exigencies of the road, just as they are for those of tramway traffic, because, as soon as an extra strain is to be met, there is always the resource of coupling up fresh batteries held in reserve--a process which amounts to the same as yoking new horses to the vehicle in order to take it up a hill. in practice, however, it is found that the jerky vibratory motion of the gasoline automobile provides for this in a way almost as convenient, although not so pleasant. the chance of the steam-engine being largely adopted for automobile work and for road traffic generally depends principally on the prospects of inventing a form of cylinder--or its equivalent--which will enable the driver to couple up fresh effective working parts of his machinery at will, just as may be done with storage batteries. a new form of steam cylinder designed to provide for this need will outwardly resemble a long pipe--one being fixed on each lower side of the vehicle--but inwardly it will be divided into compartments each of which will have its own separate piston. practically there will thus be a series of cylinders having one piston-rod running through them all, but each having its own piston. normally, this machine will run with an admission of steam to only one or two of the cylinders; but when extra work has to be done the other cylinders will be called into requisition by the opening of the steam valves leading to them. provision can be made for the automatic working of this adjustment by the introduction of a spring upon the piston-rod, so arranged that, as soon as the resistance reaches a certain point, a lever is actuated which opens the valves to admit steam to the reserve cylinders of the engine. on such occasions, of course, the consumption of steam must necessarily be greatly increased; but on the other hand the automatic system of the admission to each cylinder also results in a shutting off of the steam when little or no work is required. in fact, with a fully automatic action, regulating the consumption of steam exactly according to the amount of force necessary to drive the automobile, it would be possible to work even a single cylinder to much greater advantage than is done by the machines generally in use. so heavy are the storage batteries needed for electric traction of the road motor-car that practically it is not found convenient to carry enough of cells to last for more than a twenty-mile run. the batteries must then either be replaced, or a delay of some three hours must occur while they are being recharged. the idea of establishing charging stations at almost every conceivable terminus of a run is quite chimerical; and, even if hundreds of such stations were provided for the convenience of the users of electric traction, the limitation imposed by being forced to follow the established routes would always give to the non-electric motor an advantage over its competitor. the best hope for the storage battery on the automobile rests upon its convenience as a repository of reserve power in conjunction with such a prime motor as the steam-engine. a turbine worked by a jet of steam, as already described, and moving in a magnetic field to generate electricity for storage in a few cells, is a convenient form in which steam and electricity can be yoked together in order to secure a power of just the type suitable for driving an automobile. in the machine indicated the supply of the motive power is direct from the storage batteries, which can be coupled up in any required number according to the exigencies of the road. automatic gear may be introduced by an adaptation of the principle already referred to. in a light road-motor for carrying one or two persons on holiday trips or business rounds, the quality of adaptability of the source of power to the sudden demands due to differences of level in the road is not so absolutely essential as it is in traction engines designed for the transport of goods over ordinary roads. in the former class of work the waste of power involved in employing a motor of strength sufficient to climb hills--although the bulk of the distance to be travelled is along level roads--may not be at all so serious as to overbalance the many and manifest advantages of the automobile principle. at the same time, as has already been indicated, there is no doubt whatever that when proper automatic shut-off contrivances have been applied for economising mechanical energy in the passenger road-motor, an immense impetus will be given to its advancement. in the road traction-engine the need for what may be termed _effort_ on the part of the mechanism is much greater, more especially as the competition against horse-traction is conducted on terms so much more nearly level. a team of strong draught-horses driven by one man on a well-loaded waggon is a far more economical installation of power than a two-horse buggy carrying one or two passengers. the asphalt and macadamised tracks which are now being laid down along the sides of roads for the convenience of cyclists, are the significant forerunners of an improvement destined to produce a revolution in road traffic during the twentieth century. when automobiles have become very much more numerous, and local authorities find that the settlement of wealthy or comparatively well-to-do families in their neighbourhoods may depend very largely upon the question whether light road-motor traffic may be conveniently conducted to and from the nearest city, an immense impetus will be administered to the reasonable efforts made for catering for the demand for tracks for the accommodation of automobiles, both private and public. the tyranny of the railway station will then be to a large extent mitigated, and suburban or country residents will no longer be practically compelled to crowd up close to each station on their lines of railroad. under existing conditions many of those who travel fifteen or twenty miles to business every day live just as close to one another, and with nearly as marked a lack of space for lawn and garden, as if they lived within the city. the bunchy nature of settlement promoted by railways must have excited the notice of any intelligent observer during the past twenty or thirty years--that is to say since the suburban railroad began to take its place as an important factor in determining the locating of population. to a very large extent the automobile will be rather a feeder to the railway than a rival to it; and all sorts of by-roads and country lanes will be improved and adapted so as to admit of residents running into their stations by their own motor-cars and then completing their journeys by rail. but when this point has been reached, and when fairly smooth tracks adapted for automobile and cycling traffic have been laid down all over the country, a very interesting question will crop up having reference to the practicability of converting these tracks into highways combining the capabilities both of roads and of railways. in an ordinary railroad the functions of the iron or steel rails are twofold, first to carry the weight of the load, and second to guide the engine, carriage or truck in the right direction. now the latter purpose--in the case of a rail-track never used for high speeds, especially in going round curves--might be served by the adoption of a very much lighter weight of rail, if only the carrying of the load could be otherwise provided for. in fact, if pneumatic-tyre wheels, running on a fairly smooth asphalt track, were employed to bear the weight of a vehicle, there would then be no need for more than one guide-rail, which might readily be fixed in the middle of the track; but this should preferably be made to resemble the rail of a tram rather than that of a railroad. "every man his own engine-driver" will be a rule which will undoubtedly require some little social and mechanical adjustment to carry out within the limits of the public safety. but the automobile, even in its existing form, makes the task of completing this adjustment practically a certainty of the near future; and as soon as it is seen that motor tracks with guide lines render traffic safer than it is on ordinary roads, the main objections to the innovation will be rapidly overcome. the rule of the road for such guide-line tracks will probably be based very closely on that which at present exists for ordinary thoroughfares. on those roads where two tracks have been laid down each motor will be required to keep to the left, and when a traveller coming up behind is impatient at the slow rate of speed adopted by his precursor he will be compelled to make the necessary détour himself, passing into the middle of the thoroughfare and there outstripping the party in front, without the assistance of the guide-rail, and rejoining the track. to execute this movement, of course, the motor wheels for the guide-tracks must be mounted on entirely different principles from those adapted for railroad traffic. the broad and soft tyred wheels which bear upon the asphalt track will be entrusted with the duty of carrying the machine without extraneous aid; but there will be two extra wheels, one in front and one at the rear, capable of being lifted at any time by means of a lever controlled by the driver. these guiding wheels will fit into the groove of the tram line in the centre, being made of a shape suitable for enabling the driver to pick up the groove quickly whenever he pleases. the carrying wheels of the vehicle in this system are enabled to pass over the guide-rail readily, because the latter does not stand up from the track like the line in a railroad. a simpler plan, particularly adapted for roads which are to have only a single guide-rail, is to place the rail at the off-side of the track, and to raise it a few inches from the ground. the wheels for the rail are attached to arms which can be raised and lifted off the rail by the driver operating a lever. guiding irons, forming an inverted y, are placed below the bearings of the wheels to facilitate the picking up of the rail, their effect being that, if the driver places his vehicle in approximately the position for engaging the side wheels with the rail and then goes slowly ahead, he will very quickly be drawn into the correct alignment. of course the rails for this kind of track can be very light and inexpensive in comparison with those required for railroads on which the whole weight of each vehicle, as well as the lateral strain caused by its guidance, must fall upon the rail itself. the asphalt track and its equivalent will be the means of bringing much nearer to fulfilment the dream of having "a railway to every man's door". many such tracks will be equipped with electric cables as well as guiding-rails, so that cars with electric motors will be available for running on them, and the power will be supplied from a publicly-maintained station. some difficulty may at first be experienced in adjusting the rates and modes of payment for the facilities thus offered; but a convenient precedent is present to hand in the class of enactment under which tramway companies are at present protected from having their permanent ways used by vehicles owned by other persons. practically the possession of a vehicle having a flanged wheel and a gauge exactly the same as that of the tram lines in the vicinity may be taken to indicate an intention to use the lines. similarly a certain relation between the positions of guiding wheels and those of the connections with cables may be held to furnish evidence of liability to contribute towards the maintenance of motor-tracks. roads and railways will be much more closely inter-related in the future than they have been in the past. the competition of the automobile would in itself be practically sufficient to force the owners of railways into a more adaptive mood in regard to the true relations between the world's great highways. the way in which the course of evolution will work the problem out may be indicated thus:--first, the owners of automobiles will find it convenient in many instances to run by road to the nearest railway station which suits their purposes, leaving their machines in charge of the stationmaster and going on by train. in course of time the owners of "omnibus automobiles" will desire to secure the same advantage for their customers, and on this account the road cars will await the arrival and departure of every train just as horse vehicles do at present. the next step will be taken by the railway companies, or by the local authorities, when it becomes obvious that there is much more profit in motor traffic than there ever was in catering for the public by means of vehicles drawn by horses. each important railway station will have its diverging lines of motor-traffic for the convenience of passengers, some of them owned and managed by the same authority as the railway line itself. rivalry will shortly enforce an improvement upon this system, because in the keen competition between railway lines those stations will attract the best parts of the trade at which the passengers are put to the smallest amount of inconvenience. the necessity for changing trains, with its attendant bustle of looking after luggage, perhaps during very inclement weather, always acts as a hindrance to the popularity of a line. when "motor-omnibuses" are running by road all the way into the city, setting people down almost at their doors and making wide circuits by road, the proprietors of these vehicles will make the most of their advantages in offering to travellers a cosy and comfortable retreat during the whole of their journey. road-motors, comfortably furnished, will therefore be mounted upon low railway trucks of special construction, designed to permit of their being run on and off the trucks from the level of the ground. the plan of mounting a road vehicle upon a truck suited to receive it has already been adopted for some purposes, notably for the removal of furniture and similar goods; and it is capable of immense extension. an express train will run through on the leading routes from which roads branch out in all directions, and as it approaches each station it will uncouple the truck and "motor-omnibus" intended for that destination. the latter will be shunted on to a loopline. the road-motor will be set free from its truck and will then proceed on its journey by road. when a similar system has been fully adapted for the conveyance of goods by rail and road experiments will then be commenced, on a systematic basis, with the object of rendering possible the picking up of packages, and even of vehicles, without stopping the train. the most pressing problem which now awaits solution in the railway world is how to serve roadside stations by express trains. "through" passengers demand a rapid service; while the roadside traffic goes largely to the line that offers the most frequent trains. in the violent strain and effort to combine these two desiderata the most successful means yet adopted have been those which rely upon the destruction of enormous quantities of costly engine-power by means of quick-acting brakes. the amount of power daily converted into the mischievous heat of friction by the brakes on some lines of railway would suffice to work the whole of the traffic several times over; but the sacrifice has been enforced by the public demand for a train that shall run fast and shall yet stop as frequently as possible. progress in this direction has reached its limit. a brake that shall conserve, instead of destroying, the power of the train's inertia on pulling up at a station is urgently required; but the efforts towards supplying the want have not, so far, proved very successful. each carriage or truck must be fitted with an air-pump so arranged that, on the application of the brake by the engine-driver, it shall drive back a corresponding amount of air to that which has been liberated from the reservoir, and the energy thus stored must be rendered available for re-starting the train. trials in this direction have been made through the application of strong springs which are caused to engage upon the wheels when the brake is applied, and thus are wound up, but which may then be reversed in position, so that for the starting of the vehicle the rebound of the spring offers material assistance. it is obvious, however, that the use of compressed air harmonises better with the railway system than any plan depending upon springs. the potential elasticity in an air-reservoir of portable dimensions is enormously greater than that of any metallic spring which could conveniently be carried. in picking up and setting down mail-bags a system has been for some years in operation on certain railway lines indicating in a small way the possibilities of the future in the direction of obviating the need for stopping trains at stations. the bag is hung on a sliding rod outside of the platform, and on a corresponding part of the van is affixed a strong net, which comes in contact with the bag and catches it while the train goes past at full speed. dropping a bag is, of course, a simpler matter. the occasionally urgent demand for the sending of parcels in a similar manner has set many inventive brains to work on the problem of extending the possibilities of this system, and there seems no reason to doubt that before long it will be practicable to load some classes of small, and not readily broken, articles into trucks or vans while trains are in motion. the root idea from which such an invention will spring may be borrowed from the sliding rail and tobogganing devices already introduced in pleasure grounds for the amusement of those who enjoy trying every novel excitement. a light and very small truck may be caused to run down an incline and to throw itself into one of the trucks comprising a goods train. the method of timing the descent, of course, will only be definitely ascertained after careful calculation and experiments designed to determine what length of time must elapse between the liberation of the small descending truck and the passing of the vehicle into which its contents are to be projected. foot-bridges over railway lines at wayside stations will afford the first conveniences to serve as tentative appliances for the purpose indicated. from the overway of the bridge are built out two light frameworks carrying small tram-lines which are set at sharp declivities in the directions of the up and the down trains respectively, and which terminate at a point just high enough to clear the smoke-stack of the engine. the small truck, into which the goods to be loaded are stowed with suitable packings to prevent undue concussion, is held at the top of its course by a catch, readily released by pressure on a lever from below. the guard's van is provided at its front end with a steel, upright rod carrying a cross-piece, which is easily elevated by the guard or his assistant in anticipation of passing any station where parcels are to be received by projection. at the rear of the van is an open receptacle communicating by a door or window with the van itself. at the instant when the steel cross-piece comes in contact with the lever of the catch, which holds the little truck in position on the elevated footbridge, the descent begins, and by the time that the receptacle behind the van has come directly under the end of the sloping track the truck has reached the latter point and is brought to a sudden standstill by buffers at the termination of the miniature "toboggan". the ends of the little truck being left open, its contents are discharged into the receptacle behind the van, from which the guard or assistant in charge removes them into the vehicle itself. for catching the parcels thrown out from the van a much simpler set of apparatus is sufficient. on a larger scale, no doubt in course of time, a somewhat similar plan will be brought into operation for causing loaded trucks to run from elevated sidings and to join themselves on to trains in motion. one essential condition for the attainment of this object is that the rails of the siding should be set at such a steep declivity that, when the last van of the passing train has cleared the points and set the waiting truck in motion by liberating its catch, the rate of speed attained by the pursuing vehicle should be sufficiently high to enable it to catch the train by its own impetus. it may be found more convenient on some lines to provide nearly level sidings and to impart the necessary momentum to the waiting truck, partly through the propelling agency of compressed air. any project for what will be described as "shooting a truck loaded with valuable goods after the retreating end of a train," in order to cause it to catch up with the moving vehicles, will no doubt give rise to alarm; and this feeling will be intensified when further proposals for projecting carriages full of passengers in a similar method come up for discussion. but these apprehensions will be met and answered in the light of the fact that in the earlier part of the nineteenth century critics of what was called "stephenson's mad scheme" of making trains run twenty or even thirty miles an hour were gradually induced to calm their nerves sufficiently to try the new experience of a train journey! the wire-rope tramway has hitherto been used principally in connection with mines situated in very hilly localities. trestles are erected at intervals upon which a strong steel rope is stretched and this carries the buckets or trucks slung on pulley-blocks, contrived so as to pass the supports without interference. a system of this kind can be worked electrically, the wire-rope being employed also for the conveyance of the current. but an inherent defect in the principle lies in the fact that the wire-rope dips deeply when the weight passes over it, and thus the progress from one support to another resolves itself into a series of sharp descents, followed by equally sharp ascents up a corresponding incline. the usual way of working the traffic is to haul the freight by means of a rope wound round a windlass driven by a stationary engine at the end. the constantly varying strain on the cable proves how large is the amount of power that must be wasted in jerking the buckets up one incline to let them jolt down another when the point of support has been passed. hitherto the wire-rope tramway has been usually adopted merely as presenting the lesser of two evils. if the nature of the hills to be traversed be so precipitous that ruinous cuttings and bridges would be needed for the construction of an ordinary railway or tramway line, the idea of conveyance by wire suggests itself as being, at least, a temporary mode of getting over the difficulty. but a great extension of the principle of overhead haulage may be expected as soon as the dipping of the load has been obviated, and the portion of the moving line upon which it is situated has been made rigid. a strong but light steel framework, placed in the line of the drawing-cable, and of sufficient length to reach across two of the intervals between the supports, may be drawn over enlarged pulleys and remain quite rigid all the time. the weight-carrying wire-rope is thus dispensed with, and the installation acquires a new character, becoming, in point of fact, a moving bridge which is drawn across its supports and fits into the grooves in the wheels surmounting the latter. the carriage or truck may be constructed on the plan adopted for the building of the longest type of modern bogie carriages for ordinary railways, the tensile strength of steel rods being largely utilised for imparting rigidity. we now find that instead of a railway we have the idea of what may be more appropriately called a "wheelway". the primitive application of the same principle is to be seen in the devices used in dockyards and workshops for moving heavy weights along the ground by skidding them on rollers. practically the main precaution observed in carrying out this operation is the taking care that no two rollers are put so far apart that the centre of gravity of the object to be conveyed shall have passed over one before the end has come in contact with the next just ahead of it. the "wheelway" itself will be economical in proportion as the length of the rigid carriage or truck which runs upon it is increased. the carrying of cheap freight will be the special province of the apparatus, and it will therefore be an object to secure the form of truck which will give, with the least expense, the greatest degree of rigidity over the longest stretch of span from one support to another. some modification of the tubular principle will probably supply the most promising form for the purpose. the hope of this will be greatly enhanced through the recent advances in the art of tube-constructing by which wrought-iron and tough steel tubes can be made quite seamless and jointless, being practically forged at one operation in the required tubular shape. for mining and other similar purposes, the long tubal "wheelway" trucks of this description can be drawn up an incline at the loading station so as to be partially "up-ended" in position for receiving the charges or loads of mineral or other freight. after this they can be despatched along the "wheelway" on the closing of the door at the loading end. in regard to the mode of application of the power in traction, the shorter-distance lines may serve their objects well enough by adopting the endless wire-rope system at present used on many mining properties. but it is found in practice that for heavy freight this endless cable traction does not suit over distances of more than about two miles. mining men insist upon the caution that where this length of distance has to be exceeded in the haulage of ore from the mine over wire-rope tramways, there is need for two installations, the loaded trucks being passed along from one to the other by means of suitable appliances at the termini. electric traction must, in the near future, displace such a cumbrous system, and the plan upon which it will be applied will probably depend upon the use of a steel cable along which the motor-truck must haul itself in its progress. this cable will be kept stationary, but gripped by the wheels and other appliances of the electric motors with which the long trucks are provided. besides this there must also be the conducting cables for the conveyance of the electric current. for cheap means of transport in sparsely-developed country, as well as in regions of an exceptionally hilly contour, the "wheelway" has a great future before it. ultimately the system can be worked out so as to present an almost exact converse of the railway. the rails are fixed on the lower part of the elongated truck, one on each side; while the wheels, placed at intervals upon suitable supports, constitute the permanent way. the amount of constructional work required for each mile of track under this plan is a mere fraction of that which is needed for the permanent way and rolling stock of a railway, the almost entire absence of earth-works being, of course, a most important source of economy. probably the development of transport on the principles indicated by the evolution of the ropeway or wire-rope tramway will take place primarily in connection with mining properties, and for general transport purposes in country of a nature which renders it unsuitable for railway construction. this applies not merely to hilly regions, but particularly to those long stretches of sandy country which impede the transport of traffic in many rich mining regions, and in patches separating good country from the seaboard. in the "wheelway" for land of this character the wheels need not be elevated more than a very few feet above the ground, just enough to keep them clear of the drift sand which in some places is fatal to the carrying out of any ordinary railway project. the conception of a truck or other vehicle that shall practically carry its own rail-road has been an attractive one to some inventive minds. in sandy regions, and in other places where a railway track is difficult to maintain, and where, at any rate, there would hardly be sufficient traffic to encourage expenditure in laying an iron road, a very great boon would be a kind of motor which would lay its own rails in front of its wheels and pick them up again as soon as they had passed. a carriage of this kind was worked for some time on the landes in france. the track was virtually a kind of endless band which ran round the four wheels, bearing a close resemblance to the ramp upon which the horse is made to tread in the "box" type of horse-gear. several somewhat similar devices have been brought out, and a gradual approach seems to have been made towards a serviceable vehicle. a large wheel offers less resistance to the traction of the weight upon it than a small one. the principal reason for this is that its outer periphery, being at any particular point comparatively straight, does not dip down into every hollow of the road, but strikes an average of the depressions and prominences which it meets. the pneumatic tyre accomplishes the same object, although in a different way, the weight being supported by an elastic surface which fits into the contour of the ground beneath it; and the downward pressure being balanced by the sum total of all the resistant forces offered by every part of the tyre which touches the ground, whether resting on hollows or on prominences. careful tests which have been made with pneumatic-tyred vehicles by means of various types of dynamometer have proved that, altogether apart from the question of comfort arising from absence of vibration, there is a very true and real saving of actual power in the driving of a vehicle on wheels fitted with inflated tubes, as compared with the quantity that is required to propel the same vehicle when resting on wheels having hard unyielding rims. so far as cycles and motor-cars are concerned, this is the best solution of the problem of averaging the inequalities of a road that has yet been presented; but when we come to consider the making of provision for goods traffic carried by traction engines along ordinary roadways, the difficulties which present themselves militating against the adoption of the pneumatic principle--at any rate so long as a cheap substitute for india-rubber is undiscovered--are practically insurmountable. large cart wheels of the ordinary type are much more difficult to construct than small ones, besides being more liable to get out of order. the advantages of a large over a small wheel in reducing the amount of resistance offered by rough roads have long been recognised, and the limit of height was soon attained. in looking for improvement in this direction, therefore, we must inquire what new types of wheel may be suggested, and whether an intermediate plan between the endless band, as already referred to, and the old-fashioned large wheel may not find a useful place. let the wheel consist of a very small truck-wheel running on the inside of a large, rigid steel hoop. the latter must be supported, to keep it from falling to either side, by means of a steel semi-circular framework rising from the sides of the vehicle and carrying small wheels to prevent friction. we now have a kind of rail which conforms to the condition already mentioned, namely, that of being capable of being laid down in front of the wheel of the truck or vehicle, and of being picked up again when the weight has passed over any particular part. the hoop, in fact, constitutes a rolling railway, and the larger it can with convenience be made, the nearer is the approach which it presents to a straight railway track as regards the absence of resistance to the passing of a loaded truck-wheel over it. the method of applying the rolling hoop, more particularly as regards the question whether two or four shall be used for a vehicle, will depend upon the special work to be performed. some vehicles, however, will have only two hoops, one on each side, but several small truck-wheels running on the inside of each. a vehicle of this pattern is not to be classed with a two-wheeled buggy, because it will maintain its equilibrium without being held in position by shafts or other similar means. so far as contact with the road is concerned it is two-wheeled; and yet, in its relation to the force of gravitation upon which its statical stability depends, it is a four or six-wheeler according to the number of the small truck-wheels with which it is fitted. traction engines carrying hoops twenty feet in height, or at any rate as high as may be found compatible with stability when referred to the available width on the road, will be capable of transporting goods at a cost much below that of horse traction. the limit of available height may be increased by the bringing of the two hoops closer to each other at the top than they are at the roadway, because the application of the principle does not demand that the hoops should stand absolutely erect. similar means will, no doubt, be tried for the achievement of a modified form of what has been dreamt of by cyclists under the name of a unicycle. this machine will resemble a bicycle running on the inner rim of a hoop, and will probably attain to a higher speed for show purposes than the safety high-geared bicycle of the usual pattern. but it is in the development of goods traffic along ordinary roads that the hoop-rail principle will make its most noticeable progress. by its agency not only will the transport of goods along well-made roads become less costly and more expeditious, but localities in sparsely settled countries--such as those beyond the missouri in america and the interior regions of south africa, australia and china--will become much more readily accessible. a traction-engine and automobile which can run across broad, almost trackless plains at the rate of fifteen miles an hour will bring within quick reach of civilisation many localities in which at present, for lack of such communication, rough men are apt to grow into semi-savages, while those who retain the instincts of civilisation look upon their exile as a living death. it will do more to enlighten the dark places of the earth than any other mechanical agency of the twentieth century. chapter vi. ships. the "cargo slave" and the "ocean greyhound" are already differentiated by marked characteristics, and in the twentieth century the divergence between the two types of vessels will become much accentuated. the object aimed at by the owners of cargo boats will be to secure the greatest possible economy of working, combined with a moderately good rate of speed, such as may ensure shippers against having to stand out of their capital locked up in the cargo for too long a period. hence cheap power will become increasingly a desideratum, and the possible applications of natural sources of energy will be keenly scrutinised with a view to turning any feasible plan to advantage. the sailing ship, and the economic and constructive lines upon which it is built and worked, will be carefully overhauled with a view to finding how its deficiencies may be supplemented and its good points turned to account. one result of this renewed attention will be to confirm, for some little time, the movement which showed itself during the past decade of the nineteenth century for an increase of sailing tonnage. sooner or later, however, it will be recognised that sail power must be largely supplemented, even on the "sailer," if it is to hold its own against steam. for mails and passengers, on the other hand, steam must more and more decidedly assert its supremacy. yet the mail-packet of the twentieth century will be very different from packets which have "made the running" towards the close of the nineteenth. she will carry little or no cargo excepting specie, and goods of exceptionally high value in proportion to their weight and bulk. nearly all her below-deck capacity, indeed, will be filled with machinery and fuel. she will be in other respects more like a floating hotel than the old ideal of a ship, her cellars, so to speak, being crammed with coal and her upper stories fitted luxuriously for sitting and bed rooms and brilliant with the electric light. but in size she will not necessarily be any larger than the nineteenth century type of mail steamer. indeed the probability is that, on the average, the twentieth century mail-packets will be smaller, being built for speed rather than for magnificence or carrying capacity. the turbine-engine will be the main factor in working the approaching revolution in mail steamer construction. the special reason for this will consist in the fact that only by its adoption can the conditions mentioned above be fulfilled. with the ordinary reciprocating type of marine steam machinery it would be impossible to place, in a steamer of moderate tonnage, engines of a size suitable to enable it to attain a very high rate of speed, because the strain and vibration of the gigantic steel arms, pulling and pushing the huge cranks to turn the shafting, would knock the hull to pieces in a very short time. for this very reason, in fact, the marine architect and engineer have hitherto urged, with considerable force of argument, that high speed and large tonnage must go concomitantly. practically, only a big steamer, with the old type of marine-engine, could be a very fast one, and, for ocean traffic at any rate, a smaller vessel must be regarded as out of the running. very large tonnage being thus made a prime necessity, it followed that the space provided must be utilised, and this need has tended to perpetuate the combination of mail and passenger traffic with cargo carrying. the first step towards the revolution was taken many years ago when the screw propeller was substituted for the paddle-wheel. the latter means of propulsion caused shock and vibration not only owing to the thrusts of the piston-rod from the steam-engine itself, but also from the impact of the paddles upon the water one after the other. a great increase in the smoothness of running was attained when the screw was invented--a propeller which was entirely sunk in the water and therefore exercised its force, not in shocks, but in gentle constant pressure upon the fluid around it. such as the windmill is for wind and the turbine water-wheel for water was the screw propeller, although adapted, not as a generator, but as an application of power. having made the work and stress continuous, the next thing to be accomplished was to effect a similar reform in the engines supplying the power. this is accomplished in the turbine steam-engine by causing the steam to play in strong jets continuously and steadily upon vanes which form virtually a number of small windmills. thus, while the screw outside of the hull is applying the force continuously, the steam in the inside is driving the shafting with equal evenness and regularity. the steam turbine does not appear to have by any means reached finality in its form, such questions as the angle of impact which the jet should make with the surface of the vane, and the size of the orifice through which the steam should be ejected, being still debatable points. but on one matter there is hardly any room for doubt, and that is that the best way to secure the benefit of the expansive power of steam is to permit it to escape from a pipe having a long series of orifices and to impinge upon a correspondingly numerous series of vanes, or, perhaps, upon a number of vanes arranged so that each one is long enough to receive the impact of many jets. hitherto the steam supply-pipe emitting the jet has been placed outside of the circle of the wheel; but the future form seems likely to be one in which the axis of the wheel is itself the pipe which contains the steam, but which permits it to escape outwards to the circumference of the wheel. the latter is, in this form of turbine, made in the shape of a paddle-wheel of very small circumference but considerable length, the paddles being set at such an inclination as to obtain the greatest possible rotative impulse from the outward-rushing steam. the pipe must be turned true at intervals to enable it to carry a number of diminutive wheels upon which these long vanes are mounted, and a very strong connection must be made between these wheels and the shaft of the screw. inasmuch as a high speed of rotation is to be maintained, the pitch of the screw in the water is set so as to offer but slight opposition to the water at each turn. the immense speed attained is thus due, not to the actual power with which the water is struck by the screw at each revolution, but to the extraordinary rapidity with which the shaft rotates. the twin screw, with which the best and safest of modern steam-ships are all fitted, will soon develop into what may be called "the twin stern". each screw requires a separate set of engines and the main object of the duplication is to lessen the risk of the vessel being left helpless in case of accident to one or other. the advisability of placing each engine and shafting in a separate water-tight compartment has therefore been seen. at this point there presents itself for consideration the advisability of separating the two screws by as wide a distance as may be convenient and placing the rudder between the two. practically, therefore, it will be found best to build out a steel framework from each side of the stern for holding the bearings of each screw in connection with the twin water-tight compartments holding the shafting; and thus will be evolved what will practically represent a twin, or double, stern. in the case of the turbine steamer several of the forms of screw which were first proposed when that type of propeller was invented will again come up for examination, notably the archimedean screw, wound round a fairly long piece of shafting. the larger the circular area of this screw is the less will be the risk of "smashing" the water, or of losing hold of it entirely in rough weather. with twin screws of the large archimedean type the propelling apparatus of a turbine steamer will--if the screws are left open--be objected to on the ground of liability to foul or to get broken in crowded fairways. hence will arise a demand for accommodation for each screw in a tube forming part of the lower hull itself and open at the side for the taking in of water, while the stern part is equally free. in this way there is evolved a kind of compromise between the two principles of marine propulsion, by a screw and by a jet of water thrown to sternward. the water-jet is already very successfully employed for the propulsion of steam lifeboats in which, owing to the danger of fouling the life-saving and other tackle, an open screw is objectionable. the final extermination of the sailing ship is popularly expected as one of the first developments of the twentieth century in maritime traffic. steam, which for oversea trade made its entrance cautiously in the shape of a mere auxiliary to sail power, had taken up a much more self-assertive position long before the close of the nineteenth century, and has driven its former ally almost out of the field in large departments of the shipping industry. yet a curious and interesting counter movement is now taking place on the pacific coast of america, as well as among the south sea islands and in several other places where coal is exceptionally dear. trading schooners and barques used in these localities are often fitted with petroleum oil engines, which enable them to continue their voyages during calm or adverse weather. for the owners of the smaller grade of craft it was a material point in recommendation of this movement that, having no boiler or other parts liable to explode and wreck the vessel, an oil engine may be worked without the attendance of a certificated engineer. as soon as this legal question was settled a considerable impetus was given to the extension of the auxiliary principle for sailing ships. the shorter duration of the average voyage made by the sail-and-oil power vessels had the effect of enabling shippers to realise upon the goods carried more speedily than would have been possible under the old system of sail-power alone. it is already found that in the matter of economy of working, including interest on cost of vessel and cargo, these oil-auxiliary ships can well hold their own against the ordinary steam cargo slave. up to a certain point, the policy of relying upon steam entirely, unaided by any natural cheap source of power, has been successful; but the rate of speed which the best types of marine engines impart to this kind of vessel is strictly limited, owing to considerations of the enormous increase of fuel-consumption after passing the twelve or fourteen mile grade. for ocean greyhounds carrying mails and passengers the prime necessity of high speed has to a large extent obliterated any such separating line between waste and economy. it is, however, a mistake to imagine that the cargo steamer of the future will be in any sense a replica of the mail-boat of to-day. the opposition presented by the water to the passage of a vessel increases by leaps and bounds as soon as the rate now adopted by the cargo steamer is passed, and thus presents a natural barrier beyond which it will not be economically feasible to advance much further. if then we recognise clearly that steam cargo transport across the ocean can only be done remuneratively at about one half the speed now attained by the very fastest mail-boats, we shall soon perceive also that the chances of the auxiliary principle, if wisely introduced, placing the "sailer" on a level with the cargo ship worked by steam alone, are by no means hopeless. a type of vessel which can be trusted to make some ten or twelve knots regularly, and which can also take advantage of the power of the wind whenever it is in its favour, must inevitably possess a material advantage over the steam cargo slave in economy of working, while making almost the same average passages as its rival. then, also, the sailless cargo slave, in the keen competition that must arise, will be fitted with such appliances as human ingenuity can in future devise, or has already tentatively suggested, for invoking the aid of natural powers in order to supplement the steam-engine and effect a saving in fuel. one of these will no doubt be the adoption of the heavy pendulum with universal joint movement in a special hold of the vessel so connected with an air-compression plant that its movements may continually work to fill a reservoir of air at a high pressure. the marine engines of the ordinary type will then be adapted to work with compressed air, and the true steam-engine itself will be used for operating an air compressor on the system adopted in mines. the pendulum apparatus, of course, is really a device for enabling a vessel to derive, from the power of the waves which raise her and roll her, an impetus in the desired direction of her course. inventions of this description will at first be only very cautiously and partially adopted, because if there is one thing which the master mariner fears more than another it is any heavy moving weight in the hold, the motions of which during a storm might possibly become uncontrollable. when steam was first applied to the propulsion of ships the common argument against it was that any machine worked by steam and having sufficient power to propel a vessel would also develop so much vibration as to pull her to pieces--to say nothing of the risk of having her hull shattered at one fell blow by the explosion of the steam boiler. these undoubtedly are dangers which have to be provided against, and probably the occasional lack of care has been the cause of many an unreported loss, as well as of recorded mishaps from broken tail-shafts and screws, or from explosions far out at sea. the air-compressing pendulum will no doubt be constructed on such a principle that, whenever there is any danger of its weighty movements getting beyond control or doing any damage to the vessel, its force can be instantly removed at will, and the apparatus can be brought to a standstill by the application of friction brakes and other means. the weight may be made up of comparatively small pigs of iron, which, through the opening of a valve controlled from the deck by the stem of the pendulum, can be let fall out into the hold separately. the swinging framework would then be steadied by the friction brake gripping it gradually. auxiliary machinery of this class can only be made use of, as already indicated, to a certain strictly limited extent, owing to the tendency of any swinging weight in a vessel to aggravate the rolling during heavy weather. some tentative schemes have been put forward for tapping a source of wave-power by providing a vessel with flippers, resting upon the surface of the water outside her hull, and actuating suitable internal machinery with the object of propulsion. a certain amount of encouragement has been given by the performances of small craft fitted in this way; but it is objected by sea-faring men that the behaviour of a large vessel, encumbered with outlying parts moving on the waves independently, would probably be very erratic during a storm and would endanger the safety of the ship itself. no kind of floating appendage, moving independently of the vessel, could exercise any actual force by the uprising of a wave in lifting it without being to some extent sunk in the water; and, accordingly, when the waves were running high there would be imminent risk that heavy volumes of water would get upon the apparatus and prevent the ship from righting itself. many of the schemes that have been put forward, by patent and otherwise, for the automatic propulsion of ships have entirely failed to commend themselves by reason of their taking little or no account of the behaviour of a ship, fitted with the proposed inventions, during very rough and trying weather. the swinging pendulum, with connected apparatus for compressing air or, perhaps, for generating the electric current, seems to be the most controllable and therefore the safest of the various types of apparatus which are applicable to the utilisation of wave-power for propulsion. in the construction of connecting machinery by which the movements of a pendulum hanging up from a universal joint may be transmitted to wheels or pistons operating compressors or dynamos, it is necessary to transform all motions passing in any direction through the spherical or bowl-shaped figure traced out by the end of the pendulum in the course of its swinging. this may be effected, for instance, in the case of a pendulum working air-compressors, by mounting the latter on bearings like those of the gun-carriage in a field piece, and having two of them operating one at right angles to the other. the rods which carry the air-compressing pistons are then connected to the end of the pendulum by universal joints, and the parts which have been likened to a gun-carriage are fixed on pivots so as to be able to move horizontally. air-tight joints in the pipes which lead to the compressed air reservoir are placed in the bearings of this mounting. we thus have the same kind of provision for taking advantage of a universal movement in space as is made in solid geometry by three co-ordinates at right angles to one another for measuring such movements. another plan is to have the pendulum swung in a strong steel collar and carrying at its end three or more air-compressing pumps set radially, with the piston-rods thrust outwards by a strong spring on each, but with the ends perfectly free from any attachment, yet fitted with a buffer or wheel. as the pendulum moves it throws one or more of these piston-rod ends into contact with the inner surface of the ring, driving it into the compressing pump. at the top of the pendulum there is a double or universal pipe-joint through which the air under pressure is driven to the reservoir, and by which the apparatus is also hung. this is the simplest, and in some respects the best, form. a very simple type of the wave-power motor as applied to marine propulsion is based upon an idea taken from the mode of progression adopted by certain crustaceans, namely the possession of the means for drawing in and rapidly ejecting the water. something of the kind will most probably be made available for assisting in the propulsion of sailing ships which are not furnished with machinery of any type suitable for the driving of a screw. a very much simplified form of the pendulous or rocking weight is applicable in this case. a considerable amount of cargo is stowed away in an inner hull, taking the shape of what is practically a gigantic cradle rocking upon semicircular lines of railway iron laid down in the form of ribs of the ship. to the sides of these large rocking receptacles are connected the rods carrying, at their other ends, the pistons of large force-pumps which draw the water in at one stroke and force it out to sternwards, below the water line, at the other. in this arrangement it is obvious that only the "roll" and not the "pitch" of the vessel can be utilised as the medium through which to obtain propulsive force. but it is probable that fully eighty per cent. of the movements of a vessel during a long voyage--as indicated, say, by the direction and sweep of its mast-heads--consists of the roll. each ton of goods moved through a vertical distance of one foot in relation to the hull of the vessel, has in it the potentiality of developing, when fourteen or fifteen movements occur per minute, about one horse-power. a cradle containing tons, as may therefore be imagined, can be made to afford very material assistance in helping forward a sailing ship during a calm. in such tantalising weather the "ground-swell" of the ocean usually carries past a becalmed vessel more waste energy than is ever utilised by its sails in the briskest and most propitious breeze. for sailing ships especially, the rocking form of wave-motor as an aid to propulsion will be recommended on account of the fact that when the weather is "on the beam" both of its sources of power can be kept in full use. the sailing vessel must tack at any rate with the object of giving its sail power a fair chance, and thus, when it has not a fair "wind that follows free," it must always seek to get the breeze on its beam, and therefore usually the swell must be taking it sideways. it would be only on rare occasions that a sailing vessel, if furnished with rocking gear for using the wave-power, would be set to go nearer to the teeth of the wind than she would under present conditions of using sail-power alone. the advantage of the wave-power, however, would be seen mainly during the calm and desultory weather which has virtually been the means of forcing sail-power to resign its supremacy to steam. for checking the rocker in time of heavy weather special appliances are necessary, which, of course, must be easily operated from the deck. wedge-shaped pieces with rails attached may be driven down by screws upon the sides of the vessel, thus having the effect of gradually narrowing the amplitude of the rocking motion until a condition of stability with reference to the hull has been attained. in the building of steel ships, as well as in the construction of bridges and other erections demanding much metal-work, great economies will be introduced by the reduction of the extent to which riveting will be required when the full advantages of hydraulic pressure are realised. the plates used in the building of a ship will be "knocked-up" at one side and split at the other, with the object of making joints without the need for using rivets to anything like the extent at present required. in putting the plates thus treated together to form the hull of a vessel the swollen side of one plate is inserted between the split portions of another and the latter parts are then clamped down by heavy hydraulic pressure. this important principle is already successfully used in the making of rivetless pipes, and its application to ships and bridges will be only a matter of a comparatively short time. through this reform, and the further use of steel ribs for imparting strength and thus admitting of the employment of thinner steel plates for the actual shell, the cost of shipbuilding will be very greatly reduced. hoisting and unloading machines will play a notable part in minimising the expenses of handling goods carried by sea. the grain-elevator system is only the beginning of a revolution in this department which will not end until the loading and unloading of ships have become almost entirely the work of machinery. the principle of the miner's tool known as the "sand-auger" may prove itself very useful in this connection. from a heap of tailings the miner can select a sample, by boring into it with a thin tube, inside of which revolves a shaft carrying at its end a flat steel rotary scoop. the auger, after working its way to the bottom of the heap, is raised, and, of course, it contains a fair sample of the sand at all depths from the top downwards. on a somewhat similar principle the unloading of ships laden with grain, ore, coal, and all other articles which can be handled in bulk and divided, will be carried out by machines which, by rotary action, will work their way down to the bottom of the hull and will then be elevated by powerful lifting cranes. for other classes of goods permanent packages and tramways will be provided in each ship, and trucks will be supplied at the wharf. for coastal passages across shallow but rough water like the english channel, the services of moving bridges will be called into requisition. one of these has been at work at st. malo on the french coast opposite jersey, and another was more recently constructed on the english coast near brighton. for the longer and much more important service across the channel submarine rails may be laid down as in the cases mentioned, but in addition it will be necessary to provide for static stability by fixing a flounder-shaped pontoon just below the greatest depth of wave disturbance, and just sufficient in buoyancy to take the great bulk of the weight of the structure off the rails. in this way passengers may be conveyed across straits like the channel without the discomforts of sea-sickness. the stoking difficulties on large ocean-going steamers have become so acute that they now suggest the conclusion that, notwithstanding repeated failures, a really effective mechanical stoker will be so imperatively called for as to enforce the adoption of any reasonably good device. the heat, grime, and general misery of the stoke-hole have become so deterrent that the difficulty of securing men to undertake the work grows greater year by year, and in recruiting the ranks of the stokers resort had to be had more and more to those unfortunate men whose principal motive for labour is the insatiable desire for a drinking bout. on the occasions of several shipwrecks in the latter part of the nineteenth century disquieting revelations took place showing how savagely bitter was the feeling of the stoke-hole towards the first saloon. as soon as the mechanical fuel-shifter has been adopted, and the boilers have been properly insulated in order to prevent the overheating of the stoke-hole, the stoker will be raised to the rank of a secondary engineer, and his work will cease to be looked upon as in any sense degrading. on the cargo-slave steamer and sailer a similar social revolution will be brought about by the amelioration of the conditions under which the men live and work. already some owners and masters have begun to mitigate, to a certain extent, the embargo which the choice of a sea-faring life has in times past been understood to place upon married men. positions are found for women as stewardesses and in other capacities, and it is coming to be increasingly recognised that there is a large amount of women's work to be done on board a ship. by and by, when it is found that the best and steadiest men can be secured by making some little concessions to their desire for a settled life and their objections to the crimp and the "girl at every port," and all the other squalid accessories so generally attached in the popular mind to the seaman's career, there will be a serious effort on the part of owners to remodel the community on board of a ship on the lines of a village. there will be the "ship's shop" and the "ship's school," the "ship's church" and various other institutions and societies. thus in the twentieth century the sea will no longer be regarded, to the same extent as in the past, as the refuge for the ne'er-do-well of the land-living populace; and this, more than perhaps anything else, will help to render travelling by the great ocean highways safe and comfortable. it is a common complaint on the part of owners that by far the larger part of maritime disasters are directly traceable to misconduct or neglect of duty on the part of masters, officers or crew; but they have the remedy in their own hands. chapter vii. agriculture. muscular power still carries out all the most laborious work of the farm and of the garden--work which, of course, consists, in the main, of turning the land over and breaking up the sods. in the operations of ploughing, harrowing, rolling, and so forth, the agency almost exclusively employed is the muscular power of the horse guided by man-power; with the accompaniment of a very large and exhausting expenditure of muscular effort on the part of the farmer or farm labourer. on the fruit and vegetable garden the great preponderance of the power usefully exercised must, under existing conditions, come direct from the muscles of men. spade and plough represent the badges of the rural workers' servitude, and to rescue the country residents from this old-world bondage must be one of the chief objects to which invention will in the near future apply itself. the miner has to a very large extent escaped from the thraldom of mere brute-work, or hardening muscular effort. he drills the holes in the face of the rock at which he is working by means of compressed air or power conveyed by the electric current; and then he performs the work of breaking it down by the agency of dynamite or some other high explosive. much heavy bodily labour, no doubt, remains to be done by some classes of workers in mines; but the significance of the march of improvement is shown by the fact that a larger and larger proportion of those who work under the surface of the ground, or in ore-reduction works, consists of men who are gradually being enrolled among the ranks of the more highly skilled and intelligent workers, whose duty it is to understand and to superintend pieces of mechanism driven by mechanical power. in farming and horticulture the field of labour is not so narrowly localised as it is in mining. work representing an expenditure of hundreds of thousands of pounds may be carried out in mines whose area does not exceed two or three acres; and it is therefore highly renumerative to concentrate mechanical power upon such enterprises in the most up-to-date machinery. but the farmer ranges from side to side of his wide fields, covering hundreds, or even thousands, of acres with his operations. he is better situated than the miner in respect of the economical and healthy application of horse-power, but far worse in regard to the immediate possibilities of steam-power and electrically-conducted energy. no one can feed draught stock more cheaply than he, and no one can secure able-bodied men to work from sunrise till evening at a lower wage. yet the course of industrial evolution, which has made so much progress in the mine and the factory, must very soon powerfully affect agriculture. already, in farming districts contiguous to unlimited supplies of cheap power from waterfalls, schemes have been set on foot for the supply of power on co-operative principles to the farmers of fertile land in america, germany, france, and great britain. one necessity which will most materially aid in spurring forward the movement for the distribution of power for rural work is the requirement of special means for lifting water for irrigation, more particularly in those places where good land lies very close to the area that is naturally irrigable, by some scheme already in operation but just a little too high. here it is seen at once that power means fertility and consequent wealth, while the lack of it--if the climate be really dry, as in the pacific states of america--means loss and dearth. but the presence of a source of power which can easily be shifted about from place to place on the farm for the purpose of watering the ground must very soon suggest the applicability of the same mechanical energy to the digging or ploughing of the soil. it is from this direction, rather than from the wide introduction of steam-ploughs and diggers, that the first great impetus to the employment of mechanical power on the farm may be looked for. the steam-plough, no doubt, has before it a future full of usefulness; and yet the slow progress that has been made by it during a quarter of a century suggests that, in its present form--that is to say while built on lines imitating the locomotive and the traction-engine--it cannot very successfully challenge the plough drawn by horse-power. more probable is it--as has already been indicated--that the analogy of the rock-drill in mining work will be followed. the farmer will use an implement much smaller and handier than a movable steam-engine, but supplied with power from a central station, either on his own land or in some place maintained by co-operative or public agency. just as the miner pounds away at the rock by means of compressed air or electricity, brought to his hands through a pipe or a wire, so the farmer will work his land by spades or ploughs by the same kind of mechanical power. the advantages of electrical transmission of energy will greatly favour this kind of installation on the farm, as compared with any other method of distribution which is as yet in sight. for the ploughing of a field by the electric plough a cable will be required capable of being stretched along one side of the area to be worked. on this will run loosely a link or wheel connected with another wire wound upon a drum carried on the plough and paid out as the latter proceeds across the field. for different grades of land, of course, different modes of working are advisable, the ordinary plough of a multifurrow pattern, with stump-jumping springs or weights, being used for land which is not too heavy or clayey; a disc plough or harrow being applicable to light, well-worked ground; and the mechanical spade or fork-digger--reciprocating in its motion very much like the rock-drill--having its special sphere of usefulness in wet and heavy land. in any case a wide, gripping wheel is required in front to carry the machine forward and to turn it on reaching the end of the furrow. the wire-wound drum is actuated by a spring which tends to keep it constantly wound up, and when the plough has turned and is heading again towards the cable at the side of the field, this drum automatically winds up the wire. so also when each pair of furrows has been completed, the supply-wire is automatically shifted along upon the fixed cable to a position suitable for the next pair. not only in the working, but also in the manuring, of the soil the electric current will play an important part in the revolution in agriculture. the fixing of the nitrogen from the atmosphere in order to form nitrates available as manure depends, from the physical point of view, upon the creation of a sufficient heat to set fire to it. the economic bearings of this fact upon the future of agriculture, especially in its relation to wheat-growing, seemed so important to sir william crookes that he made the subject the principal topic of his presidential address before the british association in . the feasibility of the electrical mode of fixing atmospheric nitrogen for plant-food has been demonstrated by eminent electricians, the famous hungarian inventor, nikola tesla, being among the foremost. the electric furnace is just as readily applicable for forcing the combination of an intractable element, such as nitrogen, with other materials suitable for forming a manurial base, as it is for making calcium carbide by bringing about the union of two such unsociable constituents as lime and carbon. cheap power is, in this view, the great essential for economically enriching the soil, as well as for turning it over and preparing it for the reception of seed. nor is the fact a matter of slight importance that this power is specially demanded for the production of an electric current for heating purposes, because the transmission of such a current over long distances to the places at which the manurial product is required will save the cost of much transport of heavy material. the agricultural chemist and the microbiologist of the latter end of the nineteenth century have laid considerable stress upon the prospects of using the minute organisms which attach themselves to the roots of some plants--particularly those of the leguminaceæ--as the means of fixing the nitrogen of the atmosphere, and rendering it available for the plant-food of cereals which are not endowed with the faculty of encouraging those bacteria which fix nitrogen. high hopes have been based upon the prospects of inoculating the soil over wide areas of land with small quantities of sandy loam, taken from patches cultivated for leguminous plants which have been permitted to run to seed, thus multiplying the nitrogen-fixing bacteria enormously. the main idea has been to encourage the rapid production of these minute organisms in places where they may be specially useful, but in which they do not find a particularly congenial breeding ground. the hope that any striking revolution may be brought about in the practice of agriculture by a device of this kind must be viewed in the light of the fact that, while the scientists of the nineteenth century have demonstrated, partially at least, the true reason for the beneficial effects of growing leguminous plants upon soil intended to be afterwards laid down in cereals, they were not by any means the first to observe the fact that such benefits accrued from the practice indicated. several references in the writings of ancient greek and latin poets prove definitely that the good results of a rotation of crops, regulated by the introduction of leguminous plants at certain stages, were empirically understood. in that more primitive process of reasoning which proceeds upon the assumption _post hoc, ergo propter hoc_, the ancient agriculturist was a past-master, and the chance of gleaning something valuable from the field of common observation over which he has trod is not very great. modern improvements in agriculture will probably be, in the main, such as are based upon fundamental processes unknown to the ancients. by the word "processes" it is intended to indicate not those methods the scientific reasons for which were understood--for these in ancient times were very few--but simply those which from long experience were noticed to be beneficial. good husbandry was in olden times clearly understood to include the practice of the rotation of crops, and the beneficial results to be expected from the introduction of those crops which are now discovered to act as hosts to the microbes which fix atmospheric nitrogen were not only observed, but insisted upon. from a scientific point of view this concurrence of the results of ancient and of modern observation may only serve to render the bacteriology of the soil more interesting; but, from the standpoint of an estimate of the practical openings for agriculture improvements in the near future, it greatly dwarfs the prospect of any epoch-making change actually founded upon the principle of the rotation of crops. it is, indeed, conceivable that fresh light on the life habits of the minute organisms of the soil may lead to practical results quite new; but hardly any such light is yet within the inventor's field of vision. this view of the limited prospects of practical microbiology for the fixing of nitrogen in plant-food was corroborated by sir william crookes in the presidential address already cited. he said that "practice has for a very long time been ahead of science in respect of this department of husbandry". for ages what is known as the four course rotation had been practised, the crops following one another in this order--turnips, barley, clover and wheat--a sequence which was popular more than two thousand years ago. his summing up of the position was to the effect that "our present knowledge leads to the conclusion that the much more frequent growth of clover on the same land, even with successful microbe-seeding and proper mineral supplies, would be attended with uncertainties and difficulties, because the land soon becomes what is called clover-sick, and turns barren". in regard to any practical application of microbe-seeding, the farmers of the united kingdom at the end of the nineteenth century had not, in the opinion of this eminent chemist, reached even the experimental stage, although on the continent there had been some extension of microbe cultivation. to this it may fairly be added that some of the attention attracted to the subject on the continent has been due to the natural tendency of the german mind to discover fine differences between things which are not radically distinct. under the title of "microbe-cultivation" the long-familiar practice of the rotation of crops may to some continental enthusiasts seem to be quite an innovation! in the electrical manures-factory the operations will be simply an enlargement of laboratory experiments which have been familiar to the chemist for many years. moist air, kept damp by steam, is traversed by strong electric sparks from an induction coil inside of a bottle or other liquor-tight receiver, and in a short time it is found that in the bottom of this receptacle a liquid has accumulated which, on being tested, proves to be nitric acid. there is also present a small quantity of ammonia from the atmosphere. nitrate of ammonia thus formed would in itself be a manure; but, of course, on the large scale other nitrates will be formed by mixing the acid with cheap alkalies which are abundant in nature, soda from common salt, and lime from limestone. in this process the excessive heat of the electric discharge really raises the nitrogen and oxygen of the atmosphere to a point of temperature at which chemical union is forced; or, in other words, the nitrogen is compelled to burn and to join in chemical combination with the oxygen with which formerly it was only in mechanical mixture. when nitrogen is burning, its flame is not in itself hot enough to ignite contiguous volumes of the same element;--otherwise indeed our atmosphere, after a discharge of lightning, would burn itself out!--but the continuance of an electric discharge forces into combination just a proportionate quantity of nitrogen. practically, therefore, manure in the future will mean electricity, and therefore power; so that cheap sources of energy are of the greatest importance to the farmer. with dynamos driven by steam-engines, the price of electrically-manufactured nitrate of soda would, according to the estimate of sir william crookes, be £ per ton, but at niagara, where water power is very cheap, not more than £ per ton. thus it will be seen that the cheapness of power due to the presence of the waterfall makes such a difference in the economic aspects of the problem of the electrical manufacture of manurial nitrates as to reduce the price to less than one-fifth! it must be remembered that at the close of the nineteenth century the electric installation at niagara is by very many persons looked upon as being in itself in the nature of an experiment, but at any rate there seems to be no room for doubt that the cost of natural power for electrical installations will very soon be materially reduced. even at the price quoted, namely £ per ton, the cost of nitrate of soda made with electrically combined atmospheric nitrogen compares very favourably with commercial nitrates as now imported for agriculture purposes. "chili nitrate," in fact, is about fifty per cent. dearer. when wave-power and other forms of the stored energy of the wind have been properly harnessed in the service of mankind, the region around niagara will only be one of thousands of localities at which nitrogenous manures can be manufactured electrically at a price far below the present cost of natural deposits of nitrate of soda. from the power stations all around the coasts, as well as from those on waterfalls and windy heights among the mountains, electric cables will be employed to convey the current for fixing the nitrogen of the air at places where the manures are most wanted. the rediscovery of the art of irrigation is one of the distinguishing features of modern industrial progress in agriculture. extensive ruins and other remains in assyria, egypt, india, china and central america prove beyond question that irrigation played a vastly more important part in the industrial life of the ancients than it does in that of modern mankind. this is true in spite of the fact that power and dominion ultimately fell to the lot of those races which originally dwelt in colder and more hilly or thickly-wooded regions, where the instincts of hunting and of warfare were naturally developed, so that, by degrees, the peoples who understood irrigation fell under the sway of those who neither needed nor appreciated it. in the long interval vast forests have been cleared away and the warlike habits of the northern and mountainous races have been greatly modified, but manufacturing progress among them has enabled them to perpetuate the power originally secured by the bow and the spear. the irrigating races of mankind are now held in fear of the modern weapons which are the products of the iron and steel industries, just as they were thousands of years ago terrorised by the inroads of the wild hunting men from the north. but the future of agriculture will very largely belong to a class of men who will combine in themselves the best attributes of the irrigationist and the man who knows how to use the iron weapon and the iron implement. as the manufacturing supremacy of the north becomes more and more assured by reason of the superior healthiness of a climate encouraging activity of muscle and brain, so the agricultural prospects of the warmer regions of the earth's surface will be improved by the comparative immunity of plant and of animal life from disease in a dry atmosphere. sheep, cattle and horses thrive far better in a climate having but a scanty rainfall than in one having an abundance of wet; and so, also, does the wheat plant when the limited rains happen to be timed to suit its growth, and the best kinds of fruit trees when the same conditions prevail. all this points to an immense recrudescence of irrigation in the near future. already the californians and other americans of the pacific slope have demonstrated that irrigation is a practice fully as well suited to the requirements of a thoroughly up-to-date people as it has been for long ages to those of the "unchanging east". but here again the question of cheap power obtrudes itself. the chinese, hindoos and egyptians have long ago passed the stage at which the limited areas which were irrigable by gravitation, without advanced methods of engineering, have been occupied; and the lifting of water for the supplying of their paddy fields has been for thousands of years a laborious occupation for the poorest and most degraded of the rural population. in a system of civilisation in which transport costs so little as it does in railway and steam-ship freights, the patches of territory which can be irrigated by water brought by gravitation from the hills or from the upper reaches of rivers are comparatively easy of access to a market. this fact retards the advent of the time when colossal installations for the throwing of water upon the land will be demanded. when that epoch arrives, as it assuredly will before the first half of the twentieth century has been nearly past, the pumping plants devoted to the purposes of irrigation will present as great a contrast to the lifting appliances of the east as does a fully loaded freight train or a mammoth steam cargo-slave to a coolie carrier. at the same time there must inevitably be a great extension of the useful purposes to which small motors can be applied in irrigation. year by year the importance of the sprinkler, not only for ornamental grounds such as lawns and flower-beds, but also for the vegetable patch and the fruit garden, becomes more apparent, and efforts are being made towards the enlargement of the arms of sprinkling contrivances to such an extent as to enable them to throw a fine shower of water over a very large area of ground. sometimes a windmill is used for pumping river or well-water into high tanks from which it descends by gravitation into the sprinklers, the latter being operated by the power of the liquid as it descends. this mode of working is convenient in many cases; but a more important, because a more widely applicable, method in the future will be that in which the wind-motor not only lifts the water, but scatters it around in the same operation. long helical-shaped screws, horizontally fixed between uprights or set on a swivel on a single high tower, can be used for loading the breeze with a finely divided shower of water and thus projecting the moisture to very long distances. a windmill of the ordinary pattern, as used for gardens, may be fitted with a long perforated pipe, supported by wire guys instead of a vane, a connection being made by a water-tight swivel-joint between this pipe and that which carries the liquid from the pump. in this way every stroke of the machine sends innumerable jets of water out upon the wind, to be carried far afield. gardening properties in comparatively dry climates, fitted with machines of this description, can be laid out in different zones of cultivation, determined according to the prevailing directions of the wind and the consequent distribution of the water supply. thus if the wind most frequently blows from the west the plants which require the most water must be laid out at the eastern side, not too far from the sprinkler. facilities for shutting off the supply of spray at will are, of course, very necessary. the system of watering founded on this principle depends upon the assumption that if the gardener or the farmer could always turn on the rain when he has a fairly good wind he would never lack for seasonable moisture to nourish his crops. this will be found in practice to apply correctly to the great majority of food plants. in the dry climates, which are so eminently healthy for cereals, "the early and the latter rains," as referred to in scripture, are both needed, and one of the most important applications of cheap power will be directed to supplementing the natural supply either at one end or at the other. the "tree-doctor" will be a personage of increasing importance in the rural economy of the twentieth century. he is already well in sight; but for lack of capital and of a due appreciation of the value of his services, he occupies as yet but a comparatively subordinate position. fruits, which are nature's most elaborately worked-up edible products, must come more and more into favour as the complement to the seed food represented by bread. as the demand increases it will be more clearly seen that an enormous waste of labour is involved in the culture of an orchard unless its trees are kept in perfect health. at the same time the law of specialization must operate to set aside the tree-doctor to his separate duties, just as the physician and the veterinary surgeon already find their own distinctive spheres of work. the apparatus required for the thorough eradication of disease in fruit trees will be too expensive for the average grower to find any advantage in buying it for use only a few times during the year; but the tree-doctor, with his gangs of men, will be able to keep his special appliances at work nearly all the year round. for the destruction of almost all classes of fruit-pests, the only really complete method now in sight is the application of a poisonous gas, such as hydrocyanic acid, which is retained by means of a gas-proof tent pitched around each tree. no kind of a spray or wash can penetrate between bark and stem or into the cavities on fruit so well as a gaseous insecticide which permeates the whole of the air within the included space. but the gas-tight tent system of fumigation is as yet only in its infancy, and its growth and development will greatly help to place the fruit-growing industry on a new basis, and to bring the best kinds of fruit within the reach of the middle classes, the artisans, and ultimately even the very poor. just as wheaten bread from being a luxury reserved for the rich has become the staple of food for all grades of society, so fruits which are now commonly regarded as an indulgence, although a very desirable addition to the food of the well-to-do, must, in a short time, become practically a necessity to the great mass of the people generally. the waste of effort and of wealth involved in planting trees and assiduously cultivating the soil for the growth of poor crops decimated by disease is the prime cause of the dearness of fruit. if, therefore, it be true that the fruit diet is one which is destined to greatly improve the average health of civilised mankind, it is obvious that the tree-doctor will act indirectly as the physician for human ailments. when this fact has been fully realised the public estimation in which economic entomology and kindred sciences are held will rise very appreciably, and the capital invested in complete apparatus for fighting disease in tree life will be enormously increased. very long tents, capable of covering not merely one tree each, but of including continuous rows stretching perhaps from end to end of a large orchard, will become practically essential for up-to-date fruit-culture. an elongated tent of this description, covering a row of trees, may be filled with fumes from a position at the end of the row, where a generating plant on a trolley may be situated. at the opposite end another trolley is stationed, and each movable vehicle carries an upright mast or trestle for the support of the strong cable which passes along the row over the tops of the trees and is stretched taut by suitable contrivances. attached to this cable is a flexible tube containing a number of apertures and connected at the generating station with the small furnace or fumigating box from which the poisonous gases emanate. along the ground at each side of the row are stretched two thinner wires or cables which hold the long tent securely in position. the method of shifting from one row to another is very simple. both trolleys are moved into their new positions at the two ends of a fresh row, the fastenings of the tent at the ground on the further side having been released, so that the flap of the tent on that side is dragged over the tops of the trees and may then be drawn over the top cable and down upon the other side. seen from the end, the movements of the tent thus resemble those of a double-hinged trestle in the form of an inverted v which advances by having one leg flung over the other. for this arrangement of a fumigating tent it is best that the top cable should consist of a double wire, the fabric of the tent itself being gripped between the two wires, and a flexible tube being attached to each. as progress is made from one row to another through the drawing of one flap over the other, it is obvious that the tent turns inside out at each step, and if only one cable and one tube were used, it would be difficult to avoid permitting the gas to escape into the outer air at one stage or another. but when the tubes are duplicated in the manner described, there is always one which is actually within the tent no matter what position the latter may be in. it is then only necessary that the connection with the generating apparatus at the end of the row should be made after each movement with the tube which is inside the tent. for very long rows of trees the top cable needs to be supported by intermediate trestles besides the uprights at the ends. the gas and air-proof tent can be used for various other purposes besides those of killing pests on fruit trees. one of the regular tasks of the tree-doctor will be connected with the artificial fertilisation of trees on the wholesale scale and for a purpose such as this it is necessary that the trees to be operated upon shall not be open to the outside atmosphere, but that the pollen dust, with which the air inside the tent is to be laden, shall be strictly confined during a stated period of time. those methods of fertilisation, with which the flower-gardener has in recent years worked such wonders, can undoubtedly be utilised for many objects besides those of the variation of form and hue in ornamental plants. chapter viii. mining. exploratory telegraphy seems likely to claim a position in the twentieth century economics of mining, its particular rôle being to aid in the determination of the "strike" of mineral-bearing lodes. one main reason for this conclusion consists in the fact that the formations which carry metalliferous ores are nearly always more moist than the surrounding country, and are therefore better conductors of the electrical current. indeed there is good ground for the belief that this moistness of the fissures and lodes in which metals chiefly occur has been in part the original cause of the deposition of those metals from their aqueous solutions percolating along the routes in which gravitation carries them. in the volumes of _nature_ for and will be found communications in which the present writer has set forth some of the arguments tending to strengthen the hypothesis that earth-currents of electricity exercise an appreciable influence in determining the occurrence of gold and silver, and that they have probably been to some extent instrumental in settling the distribution of other metals. the existence of currents of electricity passing through the earth's crust and on its surface along the lines of least resistance has long been an established fact. experiments conducted at harvard, u.s.a., by professor trowbridge have proved beyond a doubt that, by means of such delicate apparatus as the telephone and microphone, it is possible for the observer to state in which direction, from a given point, the best line of conductivity runs. under certain conditions the return current is so materially facilitated when brought along the line of a watercourse or a moist patch of the earth's crust, that the words heard through a telephone are distinctly more audible than they are at a similar distance when there is no moist return circuit. deflections of the compass, due to the passing of earth-currents along the natural lines of conductivity in the soil or the rocks, are so frequently noticed as to be a source of calculation to the scientific surveyor and astronomer. it can thus be shown not only that definite lines of least electrical resistance exist in the earth, but also that natural currents of greater or less strength are almost constantly passing along these lines. some of the curious and puzzling empirical rules gained from the life-long experience of miners in regard to the varying richness and poorness of mineral lodes, according to the directions in which they strike--whether north, south, east or west--may very probably be explained, and to some extent justified, by the fuller light which science may throw upon the conditions determining the action of earth-currents in producing results similar to those of electro deposition. if, in a given region of a mineral-bearing country, the geological formation is such as to lend itself to the easy conduction of currents in one direction rather than in another, the phenomenon referred to may perhaps be partially explained. but, on the other hand, the origin of the generating force which sets the currents in motion must first be studied before the true conditions determining their direction can be understood. in other words, much that is now obscure, including the true origin of the earth's magnetism, must be to some extent cleared up before the reasons for the seemingly erratic strike of earth-currents and of richness in mineral lodes can be fully explained. practice, however, may here get some distance ahead of science, and may indeed lend some assistance to the latter by providing empirical data upon which it may proceed. when once it is clearly seen that by delicate electrical instruments, such as the telephone, the microphone and the coherer as used in wireless telegraphy, the line of least resistance on any given area of the earth's surface or any given piece of its crust may be determined, the bearing of that fact in showing the best lines of moisture and therefore the likeliest lines for mineral lodes will soon be recognised in a very practical manner. no class of men is keener or more enterprising in its applications of the latest practical science to the getting of money than mining speculators. nor have they at all missed the significance of moist bands occurring in any underground workings as a very favourable augury for the close approach of highly mineralised lodes. if, then, moisture be favourable, first to the presence of mineral-bearing country and secondly to the conductivity of electrical lines, it is obvious that there is a hopeful field for the exercise of ingenuity in bringing the one into a practical relation to the other. the occult scientific reasons for the connection may not be understood; but it is sufficient for practical purposes to know that, in a certain line from the surface outcropping of a mineral lode, there has been given a demonstration of less electrical resistance along that line than is experienced in any other direction; also to know that such a line of least resistance is proved to have been, in almost innumerable instances, coincident with the best line of mineral-bearing country. the case is similar to that of the rotation of crops in its relation to scientific microbiology. the art of mining may get ahead of the science of physiography in respect of earth-currents and lines of least resistance, as showing where mineral lodes may be expected. yet there is no doubt whatever that science will not in the one case lag so far behind as it has done in the other. the first notable service rendered by systems of the kind indicated will no doubt be in connection with the rediscovery of very valuable lodes which have been followed up for certain distances and then lost. in an instance of this description much fruitless exploration drives, winzes and "jump-ups" may have been carried out in the surrounding country rock near the place where the lode last "cut out"; but, in the absence of anything to guide the mine manager and surveyor as to the direction which the search should take, nothing but loss has been involved in the quest. several properties in the same neighbourhood have, perhaps, been abandoned or suspended in operation owing to very similar causes. the whole group may perhaps have then been bought by an exploration company whose _modus operandi_ will be as follows: the terminal of the electrical exploration plant is fixed at the end of the lode where it gave out, or else immersed in the water of the shaft which is in connection with the lode system; and another similar terminal is fixed by turns in each shaft of the contiguous group. the electrical resistances offered to the return currents, or to the wireless vibrations, are then carefully measured; and the direction of the lost lode is taken to be that which shows the least resistance in proportion to the distance traversed. the work of carrying out such an investigation must of necessity be somewhat elaborate, because it may be necessary to connect in turn each shaft, as a centre, with every one of the others as subsidiaries. but the guidance afforded even of a negative character, resulting in the avoidance of useless cutting and blasting through heavy country, will prove invaluable. many matters will require attention, in following out such a line of practical investigation, which are to some extent foreign to the usual work of the mining engineer. for example, the conditions which determine the "short-circuiting" of an earth-current require to be carefully noted, because it would be fallacious to reason that because the line of least resistance lay in a certain direction, therefore an almost continuous lode would be found. moreover, the electrical method must only be relied upon as a guide when carefully checked by other considerations. other kinds of moist formations, both metalliferous and non-metalliferous, may influence the lines of least electrical resistance, besides those containing the particular metal which is being sought for. the water difficulty has enforced the abandonment of very many valuable mines in which the positions of the lodes are still well known. sunken riches lying beneath the sea in old spanish galleons have excited the cupidity and the ingenuity of speculators and engineers; but the total amount of wealth thus hidden away from view is a mere insignificant fraction of the value of the rich metalliferous lodes which lie below the water level in flooded mines. the point in depth at which the accumulation of the water renders further following of the lode impracticable may vary in different countries. in china, throughout whole provinces, there is hardly a mine to be found in which the efforts of the miners have not been absolutely paralyzed directly the water-level was reached. but in western lands, as well as in south africa and australia, the immense capacity of the pumps employed for keeping down the water has enabled comparatively wet ground to be worked to a very considerable depth. the limit, nevertheless, has been reached in many rich mining districts. pumps of the most approved type, and driven by the largest and most economical steam-engines, have done their best in the struggle against the difficulty; and yet the water has beaten them. rich as are the lodes which lie beneath the water, the mining engineer is compelled to confess that the metal value which they contain would not leave, after extraction, a sufficient margin to pay for the enormous cost of draining the shafts. in some instances, indeed, it remains exceedingly doubtful whether pumps of the largest capacity ever attained in any part of the world would cope with the task entailed in draining the abandoned shafts. the underground workings have practically tapped subterranean rivers which, to all intents and purposes, are inexhaustible. or it may be that the mine has penetrated into some hollow basin of impermeable strata filled only with porous material which is kept constantly saturated. to drain such a piece of country would mean practically the emptying of a lake. subaqueous mining is therefore one of the big problems which the mining engineer of the twentieth century must tackle. to a certain extent he will receive guidance in his difficult task from the experiences of those who have virtually undertaken submarine mining when in search of treasure lost in sunken ships. the two methods of pumping and of subaqueous mining will in some places be carried out conjointly. in such instances the work assigned to the pumping machinery will be to keep free of water those drives in which good bodies of ore were exposed when last profitable work was being carried on. all below that level will be permitted to fill with water, and the work of boring by means of compressed air, of blasting out the rock and of filling the trucks, will all be performed under the surface. for the shallower depths large tanks, open at the top, will be constructed and slung upon trucks run on rails along the lowest drives. practically this arrangement means that an iron shaft, closed at the sides and bottom, and movable on rails laid above the surface, will be employed to keep the water out. somewhat similar appliances have been found very useful in the operations for laying the foundations of bridges. the details requiring to be worked out for the successful working of subaqueous systems of mining are numerous and important. chief among these must be the needful provision for enabling the miner to see through strong glass windows near the bottom of the iron shaft, by the aid of electric lights slung in the water outside, and thus to estimate the correct positions at which to place his drills and his explosives. for this reason the work of the day must be systematically divided so that at stated intervals the clay and other materials held in suspension by the disturbed water may be allowed to settle and the water be made comparatively clear. specially constructed strainers for the mechanical filtration of the water near the ore face, and probably, also, chemical and other precipitates, will be largely resorted to for facilitating this important operation. beside each window will be provided strong flexible sleeves, terminating in gloves into which the miner can place his hands for the purpose of adjusting the various pieces of machinery required. beyond this, of course, every possible application of mechanical power operated from above will be resorted to, not only for drilling, but also for gripping and removing the shattered pieces of rock and ore resulting from the blasting operations. from the unwatered drive or tunnel downwards, the method of working as just described may be characterised as an underground application of the "open-cut system". no elaborate honeycombing of the country below the water-level will be economically possible as it is when working in dry rock. but then, again, it is becoming plain to many experts in mining that, in working downwards from the surface itself, the future of their industry offers a wide field for the extension of the open-cut system. in proportion as power becomes cheaper, the expense attendant upon the removal of clay, sand, and rock for the purpose of laying bare the cap of a lode at a moderate depth becomes less formidable when balanced against the economy introduced by methods which admit of the miner working in the open air, although at the bottom of a kind of deep quarry. while the system of close mining will hold its own in a very large number of localities, still there are other places where the increasing cheapness of power for working an open-cut and the coincident increase in the scarcity and cost of timber for supporting the ground, will gradually shift the balance of advantage on to the side of the open method. at the same time great improvements are now foreshadowed in regard to the modes of working mines by shafts and drives. some shafts will in future be worked practically as the vertical portions of tramways, having endless wire ropes to convey the trucks direct from the face or the stope to the reduction works, and thus an immense saving will be effected in the costs incidental to mining. from the neighbourhood of the place at which it has been won, the ore will be drawn in trucks, attached to the endless wire rope, first along the drive on the horizontal, and then up an incline increasing in sharpness till the shaft is reached, where the direction of motion becomes vertical. near the surface, again, there is an incline, gradually leading to the level of the ground, or rather of the elevated tramway from which the stuff is to be tipped into the mill, or, if it be mullock, on to the waste heap. the return of each truck is effected along the reverse side of the endless wire-rope cable. ventilation is an incidental work of much importance which it becomes more practicable to carry out in a satisfactory manner when an endless system of truck conveyance has been provided, reaching from the ore-face to the mill, and thence back again. the reason is mainly that the same routes which have been prepared for this traffic are available for the supply of air and for the return current which must carry off the accumulated bad gases from the underground workings. fans, operated by the cable at various places along the line of communication, keep up a brisk exchange of air, and the coming and going of the trucks themselves help to maintain a good, healthy atmosphere, even in the most remote parts of the mine. in very deep mines, where the heat becomes unbearable after a few minutes unless a strong wind be kept going underground, the forward and backward courses for traffic and ventilation together are specially advantageous. prices during the twentieth century will depend more definitely upon the cost of gold-mining than they have ever done at any former time in the world's history. in spite of all the opposition which fanaticism and ignorance could offer to the natural trend of events in the commercial and financial life of the world, the gold standard now rests on an impregnable base; and every year witnesses some new triumph for those who accept it as the foundation of the civilised monetary system. this being the case, it is obvious that the conditions affecting the production of gold must possess a very peculiar interest even for those who have never lived within hundreds of miles of any gold mine. to all intents and purposes the habit of every man is to measure daily and even hourly the value of his efforts at producing what the economist calls "utilities," against those of the gold miner. if, therefore, the latter successfully calls to his aid mechanical giants who render his work easier and who enable him to throw into the world's markets a larger proportion of gold for a given amount of effort, the result must be that the price of gold must fall, or, in other words, the prices of general commodities must rise. if, on the other hand, all other industries have been subjected to the like improved conditions of working, the effect must be to that extent to balance the rise and keep prices comparatively steady. from this point of view it will be seen that the interests of all those who desire to see a rise in general prices are to a large extent bound up in the improvement of methods for the extraction of gold. the question of cheap power does not by any means monopolise the data upon which such a problem can be provisionally decided; and yet it may be broadly stated that in the main the increased output of gold in the future depends upon the more economical production and application of power. measured against other commodities which also depend mainly upon the same factor, gold will probably remain very steady; while, in contrast with those things which require for the production taste and skill rather than mere brute force or mechanical power, gold will fall in value. in other words, the classes of articles and services depending upon the exercise of man's higher faculties of skill, taste, and mental power will rise in price. getting gold practically means, in modern times, crushing stone. this statement is subject to fewer and fewer exceptions from one decade to another, according as the alluvial deposits in the various gold-producing countries become more or less completely worked out. a partial revival of alluvial mining has been brought about through the application of the giant dredger to cheapening the process of extracting exceedingly small quantities of gold from alluvial drift and dirt. yet on the whole it will be found that the gold-mining industry, almost all the world over, is getting down to the bed-rock of ore-treatment by crushing and by simple methods of separation. thus practically we may say that the cost of gold is the cost of power in those usually secluded localities where the precious metal is found in quantities sufficient to tempt the investment of capital. from this it may be inferred that the cheap transmission of power by the electric current will effect a more profound revolution in the gold-mining industry than in almost any other. the main deterrent to the investing of money in opening up a new gold mine consists in the fact that a very large and certain expense is involved in the conveyance of heavy machinery to the locality, while the results are very largely in the nature of a lottery. when, however, the power is supplied from a central station, and when economical types of crusher are more fully introduced, this deterrent will, to a large extent, disappear. the cables which radiate from the central electric power-house in all directions can be very readily devoted to the furnishing of power to new mines as soon as it is found that the older ones have been proved unprofitable. no one will think of carrying ore to the power when it is far more economical and profitable to carry power to the ore. in this connection the principle of the division of labour becomes very important. in its bearing upon the mining industry generally, whether in its application to the precious metals or to those which are termed the baser, and even in the work of raising coal and other non-metalliferous minerals, the fact that nearly all mines occur in groups will greatly aid in determining the separation of the work of supplying power, as a distinct industry from that of mining. ore-dressing is an art which was in a very rudimentary state at the middle of the nineteenth century, when the great discoveries of gold, silver and other metals began to influence the world's markets in so striking a manner. the ancients used the jigger in the form of a wicker basket filled with crushed ore and jerked by hand up and down in water for the purpose of causing the lighter parts to rise to the top, while the more valuable portions made their way to the bottom. in this way the copper mines of spain were worked in the days of the roman empire, and probably the system had existed from time immemorial. fifty or sixty years ago the miner had got so far as to hitch his jigging basket or sieve on to some part of his machinery, generally his pumping engine, and thus to avoid the wearing muscular effort involved in moving it in the water by hand. it was not until the obvious mistake of using a machine which permitted the finest, and sometimes the richest, parts of the ore to escape had been for many years ineffectually admitted, that the "vanner," or moving endless band with a stream of water running on it, was invented with the special object of treating the finer stuff. jiggers and vanners form the staple of the miner's ore-dressing machinery at the present day. the efficiency of the latter class of separating machines, working on certain kinds of finely crushed ore, is already so great that it may be said without exaggeration that it could hardly be much improved upon, so far as percentage of extraction is concerned; and yet the waste of power which is involved is something outrageous. for the treatment of a thin layer of slimes, perhaps no thicker than a sixpence, it is necessary to violently agitate, with a reciprocating movement, a large and heavy framework. sometimes the quantity of stuff put through as the result of one horse-power working for an hour is not more than about a hundredweight. the consequence is that in large mines the nests of vanners comprise scores or even hundreds of machines. when shaking tables are used, without the addition of the endless moving bands, good work can also be done; but the waste of power is still excessive. the vanning spade and shallow washing dish are the prototypes of this kind of ore-dressing machinery. let any one place a line of finely-crushed wet ore on a flat spade and draw the latter quickly through still water, at the same time shaking it, and the result on inspection, if the speed has not been so great as to sweep all the fine grains off the surface, will be that the heavier parts of the ore will be found to have ranged themselves on the side towards which the spade was propelled in its progress through the water. a sheet of glass serves for the purpose of this experiment even better than a metal implement; but the spade is the time-honoured appliance among miners for testing some kinds of finely crushed ore by mechanical separation. it is to be observed that, besides the shaking motion imparted to the apparatus, the only active agency in the distribution of the particles is the sidelong movement of the spade relatively to the water. but it makes little or no difference whether the water moves sidelong on the spade or the latter progresses through the liquid; the ore will range itself accurately all the same. consequently, if a circular tank be used, and if the water be set in rotary motion, the ore on a sheet of glass, held steady, will arrange itself in the same way. if the ore be fed in small streams of water down the inclined surfaces of sloping glass, or other smooth shelves set close to and parallel with one another near the periphery of such a vessel of moving water, the resultant motions of the heavy and of the light particles respectively, in passing down these shelves, will be found to be so different that the good stuff can be caught by a receptacle placed at one part, while the tailings fall into another receiver which is differently situated at the place where the lighter grains fall. the main essential in this particular application of the art of vanning is simply that the water should move or drift transversely to lines of ore passing, while held in suspension with water, down a smooth sloping surface. in dealing with some very light classes of ore, and especially such as may naturally crush very fine--that is to say, with a large proportion of impalpable "slimes"--there is a decided advantage in causing the water to drift sidelong on the smooth shelf by other means than the motion in a circular tank. adopting nearly the form of the "side delivery manner," in which the moving band is canted to the side and the stuff runs off sideways, the sloping smooth shelf can be worked for ore separation with merely the streams of water holding the fine sand in suspension running down at fixed intervals. a glass covering is placed very close to this surface on which the streams run; and between the two is driven laterally a strong current of wind by means of a blast-fan, which causes each stream of water to drift a little sidewards, carrying with it the lighter particles, but leaving on its windward side a line of nearly pure ore. these small runlets can be multiplied, on a shelf measuring six or eight feet in length, to such an extent that the machine can put through as much ore as a dozen vanners, consuming only a mere fraction of the power necessary to drive one machine of the older type. cyanide solution, instead of water, is very advantageously employed for this kind of operation in the case of extracting gold from crushed ore. the method is to pump the liquid from the tanks in which it is stored and to allow it to flow back by way of the vanning apparatus, thus providing not only for catching the grains of gold by the concentrating machine, but also for the dissolving of the fine impalpable gold dust, or natural precipitate, by the action of the cyanide of potassium. upon the use of this latter chemical will be based the main improvements in the gold-mining industry during the twentieth century; and, conversely, the applications of the old system of amalgamating with mercury, in order to catch the golden particles, will be gradually restricted. fine concentrators, worked with cyanide solution, perform three operations at once, namely, first, the catching of the free gold grains; second, the production of a rich concentrate of minerals having gold in association and intended for smelting; and, third, the dissolving of the finest particles by the continual action of the chemical. in fact it is in the treatment of complex and very refractory ores generally, whether of the precious or of the baser metals, that the finer applications of the art of the ore-dresser will receive their first great impetus. the vanner, as well as the jigger, will become an instrument of precision; and in combination with rushing appliances operated by cheap power in almost unlimited quantities it will materially assist in multiplying the world's supply of metals. this again will aid in promoting the further extension of machinery. gold will be produced in greater abundance for what is called the machinery of commerce; and the base metals, particularly the new alloys of steel and also copper and aluminium, will be more largely produced for engineering and electrical purposes. the importation--particularly to england and scotland--of large quantities of highly-concentrated iron ore will cause one of the first notable developments in the mining and ore-treatment of the twentieth century so far as the united kingdom is concerned. the urgent necessity for an extension in the manufacture of bessemer steel, and of the new and remarkable alloys in which very small quantities of other metals are employed in order to impart altogether exceptional qualities to iron, must accentuate the demand for those kinds of ore which lend themselves most readily to the special requirements of the works on hand. hence the question of the transport of special kinds of iron ore over longer distances will have to be faced (as it has been already to a limited degree), and not only in reference to ores containing a low percentage of phosphorus and therefore exceptionally suitable for the bessemerising process, but also in regard to ores which are amenable to magnetic separation. magnetite, indeed, must bulk more largely in the future as a source of iron, particularly because it is susceptible of magnetic separation, a process which as yet is only in its infancy. containing, as it does, a larger percentage of iron than any other source from which the metal is commercially extracted, its employment as an ore results in great economy of fuel, as well as a reduction in the proportionate costs of transport. when ores of iron require to be brought from oversea places, it is obvious that those which will concentrate to the purest product possible, and which are in other respects specially applicable to the production of grades of steel of exceptional tensile strength, will have the preference. magnetic concentration, or the separation of an ore from the waste gangue by the attraction of powerful electro-magnets, must therefore occupy a much more prominent place in the metallurgy of the future than it has in that of the past. not only may ironstone containing magnetite be separated from other material, but several important minerals acquire the property of becoming magnetic when subjected to the operation of roasting, sometimes through a sulphide being converted into a magnetic oxide. by the use of powerful electro-magnets, the poles of which are brought to a point or to a nearly sharp knife-edge, the intensity of the magnetic field can be so enormously increased that even minerals which are only feebly magnetic can readily be separated by being lifted away from the non-magnetic material. in some systems the crushed ore is simply permitted to fall in a continuous stream through a strong magnetic field, and the magnetic particles are diverted out of the vertical in their descent by the operation of the magnets. nor is it only those minerals that actually become themselves magnetic on being roasted which can be so differentiated from the material with which they are associated as to be amenable to magnetic separation. even differences in hygroscopic properties--that is to say, in the degree of avidity with which a mineral takes up moisture from the atmosphere--may be made available for the purpose of effecting a commercially valuable separation. this is especially the case with some complex ores in which one constituent, on being roasted, acquires a much greater hygroscopic power than the others, the grains of the crushed and roasted ore becoming damp and sticky while those of the other minerals remain comparatively dry. by mixing with an ore of this kind--after it has been allowed to "weather" for a short time--some finely-powdered magnetite the strongly hygroscopic constituents can be made practically magnetic, because the magnetic impalpable dust adheres to them, while it remains separate from the grains of the other minerals. hardness--as well as magnetic attraction--is a property of ore which has as yet been made available to only a very slight extent as the basis of a system of separation. if a quantity of mixed fragments of glass and plumbago be pounded together in a mortar with only a moderate degree of pressure, so as to avoid, as far as possible, the breaking of the glass, there will soon come a stage at which the softer material can be separated from the harder simply by means of a fine sieve. there are many naturally-existing mineral mixtures in the crushing of which a similar result occurs in a very marked degree; and, indeed, there are none which do not show the peculiarity more or less, because the constituents of an ore are never of exactly the same degree of hardness. when the worthless parts are the softer and therefore have the greater tendency to "slime," the ore is very readily dressed to a high percentage by means of water. but when the reverse is the case, and the valuable constituents through their softness get reduced to a fine pulp long before the other parts, the ordinary operations of the ore-dresser become much more difficult to carry out. most elaborate ore-reduction plants are constructed with the view to causing the crushing surfaces, whether of rolls or of jaws, to merely tap each piece of stone so as to break it in bits without creating much dust. this operation is repeated over and over again; but the stuff which is fine enough to go to the concentrator is removed by sieving after each operation of the kind; and the successive rolls or other crushers are set to a finer and finer gauge, so that there is a progressive approach to the conditions of coarse sand, which is that specially desired by the ore-dresser. much of this elaboration will be seen to be needless, and, moreover, better commercial results will be obtained when it is more clearly perceived that the recovery of a valuable ore in the form of a fine slime may be economically effected by the action of grinders specially constructed for the purpose of permitting the hard constituents of the ore to remain in comparatively large grains, while the other and softer minerals are reduced to fine slimes or dust. in other words, a grinding plant, purposely designed to carry out its work in exactly the opposite way to that which has been described as the system aimed at in ordinary crushing machinery, has its place in the future of metallurgy. light mullers are employed to pound, or to press together, the crushed grains for a given length of time, and then sieving machinery completes the operation by taking out the dust from the more palpable grains. in some cases it will be found that an improvement can be effected by bringing about the separation of a finer grade of dust than could be taken out by any kind of sieve which is commercially practicable on the large scale. this is more particularly the case in regard to sulphide ores containing very friable constituents carrying silver. a fine dry dust-separator may then be employed constructed on the principle of a vibrating sloping shelf which moves rhythmically, either in a horizontal circle or with a reciprocal motion, and which at the same time alters its degree of inclination to the horizontal. when the shelf is nearly level its vibration drives the coarser particles off; but the very finest dust does not leave it until it assumes nearly a vertical position. a large nest of similar shelves, set close to, and parallel with, one another, can separate out a great quantity of well-dried slimes in a very short space of time. chapter ix. domestic. the enormous waste involved in the common methods of heating is one of the principal defects of household economy which will be corrected during the twentieth century. different authorities have made varying estimates of the proportion between the heat which goes up the chimney of an ordinary grate, and that which actually passes out into the room fulfilling its purpose of maintaining an equable temperature; but it cannot be denied that, at the very least, something like three-fourths of the heat generated by the domestic fires of even the most advanced and civilised nations goes absolutely to waste--or rather to worse than waste--because the extra smoke produced in creating it only serves to pollute the atmosphere. in the cities some degree of progress has been made in the introduction of heating appliances which really give warmth to a room without losing at least seventy-five per cent. of their heat; but in the country districts, where open fireplaces are the rule, it is not unusual to find that more than ninety per cent. of the heat produced behind the domestic hearth goes up the chimney. sentiment has had a great deal to do with retarding progress in the direction of improved house-heating appliances. for countless ages "the hearth" has been, so to speak, the domestic altar, around which some of the most sacred associations of mankind have gathered, and popular sentiment has declared that it is not for the iconoclastic inventor or architect to improve it out of existence, or even to interfere seriously with either its shape or the position in the living room from which it sheds its genial warmth and cheerfulness around the family circle. a recognition of this ineradicable popular feeling was involved in the adoption of the grate, filled with glowing balls of asbestos composition, by the makers of gas-heating apparatus. the imitation of the coal-filled grate is in some cases almost perfect; and yet it is in this close approximation to the real article that some lovers of the domestic fuel-fire find their chief objection, just as the tricks of anthropoid animals--so strongly reminiscent of human beings and yet distinct--have the effect of repelling some people far more than the ways of creatures utterly unlike man in form and feature. taking count of the domestic attachment to a real fuel-filled fireplace or grate as one of the principal factors in the problem of domestic heating, it is plain that one way of obviating the waste of heat which is at present incurred, without doing violence to that sentiment, is by making better use of the chimney. the hot-air pipes and coils which are already so largely used for indoor heating offer in themselves a hint in this direction. long pipes or coils inserted in the course taken by the heated air in ascending a chimney become warm, and it is possible, by taking such a pipe from one part of the room up the passage and back again, to cause, by means of a small rotating fan or other ventilating apparatus, the whole of the air in the chamber to circulate up the chimney and back again every few minutes, gathering warmth as it goes. in this way, and by exposing as much heating surface to the warm air in the chimney as possible, the warmth derived by an ordinary room from a fuel fire can be more than doubled. at the same time the risk of spreading "smuts" over the room can be entirely avoided first by keeping the whole length of pipe perfectly air-tight, and attaching it in such a way as to be readily removed for inspection; and, secondly, by placing the outward vent in such a position that the gentle current must mount upwards, and any dust must fall back again into a wide funnel-shaped orifice, and by covering the latter with fine wire gauze. an apparatus of this kind acts as a remover of dust from the room instead of adding any to it. one necessity, however, is the provision of motive power, very small though it be, to work the fan or otherwise promote a draught. electric heating is, however, the method which will probably take precedence over others in all those cases where systems are tried on their actual merits apart from sentiment or usage. the wonderful facility afforded by the electric heating wire for the distribution of a moderate degree of warmth, in exactly the proportions in which it may be needed, gives the electric method an enormous advantage over its rivals. the fundamental principle upon which heating by electricity is generally arranged depends upon the fact that a thin wire offers more electrical resistance to the passage of a current than a thick one, and therefore becomes heated. in the case of the incandescent lamp, in which the carbon filament requires to be raised to a white heat and must be free to emit its light without interference from opaque matter, it is necessary to protect the resisting and glowing material by nearly exhausting the air from the hermetically sealed globe or bulb in which it is enclosed. but in electrical house-warming, for which a white heat is not required and in which the necessary protection from the air can be secured by embedding the conveying medium in opaque solid material, the problem becomes much simpler, because strong metallic wires can be used, and they may be enclosed in any kind of cement which does not corrode them and which distributes the heat while refusing to conduct the electric current. a network of wire, crossing and recrossing but always carrying the same current, may be embedded in plaster and a gentle heat may be imparted to the whole mass through the resistance of the wires to the electricity and their contact with the non-conducting material. concurrently with this method of heating there is gradually being introduced a practice of using metallic lathing for the plastering of dwelling-rooms in place of the old wooden battens generally employed for lath-and-plaster work. the solution of the practical problem which has to be faced seems to depend upon the prospect of effecting a compromise between the two systems, introducing thin resisting wire as the metallic element in such work, but making all other components from non-conducting material. in the event of any "cut-out" or "short-circuiting" occurring through accidental injury to the wall, it would be very inconvenient to be compelled to knock away the plaster. moreover, it is not necessary for ordinary warming purposes that the whole of the wall, up to the ceiling, should be heated. accordingly the system which is likely to commend itself is that of constructing panels on some such principle as the one already described, and affixing them to the wall, forming a kind of solid dado from three to four feet from the floor. these can be fastened so as to facilitate removal for examination and repairs. when the current is switched on they are slowly warmed up by the heat generated through the resistance of the wires, and the air in the room is gently heated without being vitiated or deprived of its oxygen as it is by the presence of flames, whether of fuel or of gas. warming footstools will also be provided, and a room heated in this way will be found eminently comfortable to live in. this method of house-warming having once obtained a decided lead within the cities and other localities where a cheap electric current is available, somewhat similar systems, adapted for the heating of walls by hot air in tubes, instead of by resistant wires, will be largely adopted in the rural districts, more particularly in churches and other places of public assemblage. the progress made in this direction during the last few years of the nineteenth century is already noteworthy, but when electric-heating really gets a good chance to force the pace of improvement, the day will soon arrive when it will be regarded as nothing less than barbarous to ask people to sit during the winter months in places not evenly warmed all through by methods which result in the distribution of the heat exactly as it is wanted. ventilation is another household reform which will be very greatly accelerated by the presence of electric power of low cost. the great majority of civilised people, as yet, have no idea of ventilation excepting that highly unreasonable kind which depends upon leaving their houses and other buildings partly open to the outside weather. one man is sitting in church under a down draught from an open window above him, while others, in different parts of the same building, may be weltering in the heat and feeling stifled through the vitiated air. in dwelling-houses the great majority of living rooms really have no other effective form of ventilation than the draught from the fireplace. the strength of this draught, again, is regulated to a very large extent by the speed and direction of the outside wind. in calm and sultry weather, when ventilation is most needed, the current of air from the fireplace may be very slight indeed; while in the wild and boisterous days succeeding a sudden change of weather, the living rooms are subjected to such a drop in temperature and are swept by such draughts of cold air that the inmates are very liable to catch colds and influenza. hence has arisen in the british islands, and in the colder countries of europe and america, the very general desire among the poorer classes to suppress all ventilation. rooms are closed at the commencement of winter and practically remain so until the summer season. many people whose circumstances have improved, and who pass suddenly from ill-ventilated houses to those which have better access to the outside air, find the change so severe upon their constitutions and habits that they give a bad name to everything in the shape of ventilation. meanwhile the dread of draughts causes people to exclude the fresh air to such an extent that consumption and many other diseases are fostered and engendered. all this arises mainly from the very serious mistake of imagining that it is possible to move air without the exercise of force. in the case of the draught caused by a fire no doubt an active force is employed in the energy of the heated air ascending the chimney, and in the corresponding inrush. this latter is usually drawn from below the door--the very worst place from which it can be taken, seeing that in the experience of most people it is by getting the feet chilled, through draughts along the floor, that the worst colds are generally contracted. fireplaces are not unusually regarded as a direct means for ventilation, and with regard to nearly all the devices commonly adopted in houses and public buildings, it may be said that they lack the first requisite for a scientific system of renewing the air, namely a source of power by means of which to shift it from outside to inside, and _vice versâ_. there is no direction in which a more pressing need exists for the distribution of power in small quantities than in regard to the ventilation of private and public edifices. the circular fan, placed in the centre piece of the ceiling and controlled by an electric switch on the wall, is the principal type of apparatus applicable to the purposes of ventilation. as electric lighting of dwelling-houses becomes more common, and ultimately almost universal within cities, the practice will be to arrange for lighting and for ventilation at the same time. but, unfortunately, the current now principally employed for electric lighting and consisting of a series of impulses, first in one direction and then in the opposite, "alternating" with wonderful rapidity, is not well adapted for driving small motors of the types now in use. one improvement in domestic economy greatly needed in the twentieth century consists in the invention of a really effective simple and economical "alternate-current" motor. this is a matter which will be referred to in dealing with electrical machines. that the problem will be solved before many years have passed there is no good reason to doubt. in the meantime many laudable endeavours are being made towards the application of the pressure from water pipes to the purpose of driving ventilating fans. the extreme wastefulness of power and of water involved in this method of dealing with the difficulty may be partially overlooked on account of the very small amounts required to produce an effect in the desired direction; and yet there is no doubt that a recognition of the wastefulness acts to some extent as a deterrent to artificial ventilation. the benefits of the system are not sufficiently obvious or showy to induce any class of people, excepting physicians and persons fully acquainted with the principles of hygiene, to sanction a material outlay upon the object. when an exactly suitable alternate-current motor has been invented the standard electric light installation will be practically one apparatus with the ventilating fan, and the cost of the latter will hardly be felt as a separate item. in cooking there is in existing ordinary methods the same enormous waste of heat as there is in the warming of rooms. something, no doubt, has been done in the direction of economy by the invention of new and improved forms of stoves, but a great preponderance of the heat generated in the fire of even the best stove goes up the chimney. the electric oven, as already invented, is perhaps the nearest approach to a really economical "cooker" that has yet been proposed; but even before the general adoption of such an apparatus there will be ample room for improvement in the cooking stove, first as regards insulation, and secondly in the distribution of the fuel around the objects to be heated. one principal cause of the waste that goes on arises from the fact that the fire burns away from the place at which its heat is most beneficially applied, and no means are adopted, as in the case of the candle in a carriage lamp, for keeping it up to the required level. additions of fuel are made from the top with the immediate effect of checking the heat. a great advance in economy of fuel will take place when the household coal intended for cooking purposes is ground up together with the proper proportions of certain waste products of chemistry, so as to make a "smouldering mixture" which can be kept regularly supplied to a shallow or thin fire box by pressure applied from beneath or at the parts farthest away from the objects to be heated. an oven, for instance, may be surrounded by a "jacket" filled with ground smouldering mixture having a non-conducting insulator outside and a connection with a chimney. the heat from the fuel is thus kept in close proximity to the objects requiring to be cooked, and comparatively small waste results. it is by taking advantage of their superior facilities in the same direction that gas and inflammable oils have already made their mark in the sphere of domestic cookery. regarded as fuel their initial cost may be relatively heavy; and yet, owing to their more exact method of application, they often effect a saving in the end. not only do they bring the fire closer to the articles to be heated or cooked, but they also make it easy for the fire to be turned off or on, and this in itself is an important source of economy. still, with the advent of cheaper and more accessible power in every centre of population, the cost of grinding coal and of mixing it in order to form a fuel comparable in respect of convenience and economy with gas and oil will be so greatly reduced that the "black diamond" will still continue to challenge its rivals in the arena of competition presented by the demands of domestic economy. light, as well as heat and air, requires to be evenly and equably distributed throughout the dwelling-house before anything approaching an ideal residence can be secured. as the science of hygiene advances it is demonstrated more and more clearly that sunlight--and even diffused daylight--may be used as a most effective weapon against the spread of disease. alternations of deep gloom in the dwelling-house with the superior light resulting from brighter weather produce many kinds of nervous derangement, not the least deleterious of which arise from the unnecessary strain to which the eyesight is subjected. the promise of the future is that, through the abundance of windows provided in the walls, roofs and porches of our dwelling-houses--but all supplemented with shutters and blinds of various kinds--there shall be a possibility of regulating, far more accurately than at present, the accessibility of light from outside according to the brightness or dulness of the day. it is hardly to be expected that many people will build "crystal palaces" in which to reside; but with the immense progress that is being made in the construction of dwellings with iron or steel frames, and in the adaptation of various materials so that they may serve for building purposes in conjunction with metallic frameworks, it seems clear that many roofs, as well as large portions of walls, will in future be made on the composite principle, using steel and glass. these will, to a large extent, be permanently sheltered from the direct rays of the sun when high in the heavens, by shutters constructed on the louvre principle so that they may admit the light from the sky continually, but actual rays or beams of sunlight only for a short time after sunrise and at the close of day. the ceilings, if any are provided under the roofs, will also be glazed. the obstacles presented in the way of such a reform in a city like london may at first sight seem so serious as to be practically insuperable. long rows of three or four storied houses certainly offer but few facilities for the admission of light through the roofs of any but the rooms on the top floors, and yet it is in the dwelling-houses of this type that the depression caused by gloom and the absence of light during the hours of day are most severely felt as a source of nervous depression. evolution in a matter of this sort will take place gradually and along the line of least resistance. portions of courts, areas and yards will be glazed over in the way described; and it will be found that those rooms which are thus enclosed and sheltered from the wind and rain, but left open to the daylight, constitute the most cheerful sitting places in the houses. then, as rebuilding and alterations proceed, many houses will gradually be remodelled--at least as regards some of their rooms--in the same direction. physicians will become increasingly insistent on the necessity for admitting plenty of light into the abodes of the sick, more particularly of families inclined towards consumption. a very large trade will spring up during the twentieth century in household cooling apparatus for use in hot climates. the colonial expansion towards which all european races are now tending inevitably means that very many thousands of persons whose ancestors have been accustomed to life in cold or temperate climates, will be induced to dwell in the dry and warm, or in the humid tropical regions of the earth. it will be an important task of the british, continental and american machinists of the twentieth century to turn out convenient pieces of apparatus which shall be available for ventilating houses, especially during the night, and for reducing the temperature in them to something approaching that which is natural to the inmates. the old clumsy punkah will be replaced by circular fans keeping up a gentle current of air with a minimum of noise or annoyance of any kind. at present it is only in specially favoured circumstances that these quiet-working circular punkahs can be actuated by mechanical force, that is to say where a prime motor, or an electric current, or a reticulated water supply for driving a suitable machine may be at hand. in other situations the use of compressed air or gas may be resorted to, and for this purpose small capsules, similar to those already introduced for making soda water by the liberation of compressed carbonic acid gas, will be found handy. for a very small sum of money the householder will be able to purchase a sufficient number of capsules to ensure motive power for his fan during a week of hot nights. a convenient form of small motor suitable for being driven by compressed air or gases in this way is one in which a diminutive turbine or other wheel is set at the bottom of a thin tube of mercury. the capsule, being fastened to the lower end of this apparatus, liberates at very short intervals of time bubbles of air or gas, which, in the upward ascent, drive the wheel. the arrangement depends upon the fact that a stream of gas ascending in a heavy liquid behaves in the same way as a stream of water descending by its own weight and turning a water-wheel. it supplies what is perhaps the simplest and most inexpensive small motor available for the lightest domestic work to which a gentle but continuous source of power is applicable. for actually cooling the air, as well as keeping it in motion, similar devices will be resorted to, with the addition of the circulation of the current of air through coils of pipes laid under the surface of the ground. in this way householders will have all the advantages of living in cool underground rooms without incurring the discomforts and dangers which are often inseparable from that mode of life. in the coastal regions, which usually have the most trying climates for europeans living in tropical countries, a method of cooling the houses will be based on the fact that at moderate depths in the sea the prevailing temperature is a steady one, not much above the freezing point of water. almost every seaport town within the tropics--where white residents in their houses swelter nightly in the greatest discomfort from the heat--is in close proximity to deep ocean water, in which, at all seasons of the year, the regular temperature is only about thirty-four degrees fahr. the cost of steel piping strong enough to withstand the pressure of the water in places which possess absolutely the coolest temperature of the ocean would be very heavy; but, on the other hand, the actual reduction of heat demanded for the satisfactory cooling of the air in a dwelling-room is not by any means great, and at quite shallow depths the heat of the air can be satisfactorily abstracted by the sea water surrounding coils of pipes. even in colder climates it seems likely that similar systems will be found useful in producing a preliminary reduction in the temperature of the air employed in keeping fresh foodstuffs such as meat, fruits and vegetables. fruits especially, when placed in suitable receptacles, and stored at temperatures quite steady at about the freezing point of water, will not only be readily kept on land from one season to another, but will be transported to markets thousands of miles distant from the growers, and sold in practically the same condition as if they had just been picked from the trees. during the twentieth century the proportion of the fruit eaters among the peoples of the great manufacturing countries will be very largely augmented, and this result will be brought about mainly through the instrumentality of methods of keeping perishable produce free from deterioration by maintaining it almost at the freezing point--a temperature at which, under suitable conditions as regards exclusion of moisture, and steadiness of hygrometric pressure, the germs of decay in food are practically prevented from coming to maturity. for the cooling of dwelling-rooms in places distant from the sea, various systems, depending upon the supply of dry cold air from central stations through pipes to the dwellings of subscribers, will no doubt be brought into operation. this, however, will only be practicable in the more populous localities having plenty of residents ready to contribute to the expense. for more isolated houses the cooling and ventilating apparatus of the future may be a modification of the "shower-blast" which has been successfully adapted to metallurgical purposes. when downward jets of water, as in a shower-bath, are enclosed in a large pipe connected horizontally with a room but having facilities for the escape of the water underneath, a strong draught of cool air is created, and the prevailing temperature is quickly reduced. an apparatus of this kind may be intended for application either to the ventilators or to the windows of rooms. lifts for conveying persons from one storey of a building to another will probably undergo a considerable amount of modification during the next few years. the establishment of central electric stations and the distribution of electricity for lighting and for power will offer a very great premium upon the preference for electric motors for lifts. as soon as a maximum of efficiency, combined with the minimum of cost, has been attained, there will be a demand for the introduction of lifts in positions where the traffic is not large enough to warrant the constant presence of an attendant. in fact the desire will be for some kind of elevator which shall be just as free to the use of each individual as is the staircase of an ordinary house. for this purpose, inclined planes having moving canvas or similar ramps will be extensively brought into use. the passenger steps upon what is practically an endless belt having suitable slats upon it to prevent his foot from slipping, and, as the hand-railing at the side of this moves concurrently, he is taken up, without any effort, to the landing on which he may alight quite steadily. when this idea, which has already been brought into operation, has been more fully developed, it will be seen that a large circular slowly-revolving disc, set at an angle and properly furnished, will supply a more convenient form of free elevator. one side will be used by those who are going up and the other by those who wish to come down. the "well" of the staircase for such a lift is made in elliptical form, like the shadow projection of a circle. steps can be provided so that, when not in motion, the lift will be a staircase not differing much from the old style. chapter x. electric messages, etc. the telegraphic wire in the home and street will fulfil a very important part in the economy of the twentieth century. for conveying intelligence, as well as for heating, cooking and lighting, the electric current will become one of the most familiar of all the forces called in to assist in domestic arrangements. the rapidity with which the electric bell-push has taken the place of the old-fashioned knocker and the bell-hanger's system affords one indication of the readiness with which those forms of electric apparatus which are adapted to all the purposes of communicating and reminding will recommend themselves to the public during the twentieth century. in another direction the eagerness with which every advance in the telephone is hailed by the people may well offer an augury of rapid progress in the immediate future. in this department invention will aim just as much at simplification as at elaboration; and some of the pieces of domestic electrical apparatus universally used during the twentieth century will be astonishingly cheap. the call to awake in the morning will, in cities and towns, be made by wireless telegraphy, which will also be used for the purpose of regulating the domestic clocks, so that if desired any suitable form of clock alarm may be used with the most perfect confidence. a tentative system of this kind has been adopted in connection with certain telephone exchanges, in which special officers are told off whose duty it is to call those subscribers who have paid the small fee covering the expense. these officers are required to time their intimations according to the previously expressed wishes of subscribers. this kind of service, as well as the regulation of the household clock, is eminently a department of domestic economy in which wireless telegraphy will prove itself useful, because it does not demand that a subscriber shall have gone to the expense of installing a wire to his house and of paying a rent or fee for the use of one. the clock controlled by wireless telegraphy will doubtless undergo a rapid development from the time when it is first introduced. practically the same principles which enable the electrician to utilise the "hertzian waves," or ether vibrations, for the purpose of setting a clock right once a day, or once an hour, will permit of an impulse, true to time, being sent from the central station every second, or every minute, and when this has been accomplished it will be seen that there is no more use for the maintenance of elaborate clockworks at any place excepting the central station. the domestic clock will, in fact, become mainly a "receiver" for the wireless telegraphic apparatus, and its internal mechanism will be reduced, perhaps, to a couple of wheels, which are necessary to transmit the motion of a minute-hand to that which indicates the hours. the fire-alarm of the future must be very simple and inexpensive in order to ensure its introduction, not only into offices and warehouses but also into shops and houses. the fire-insurance companies will very shortly awake to the fact that prompt telegraphic alarm in case of fire is worth far more than the majority of the prohibitions upon which they are accustomed to insist by way of rendering fires less likely. the main principles upon which the electric fire-alarm will be operated have already been worked out and partially adopted. in the system of fuses and cut-outs used in connection with electric lighting, the methods of preventing fire due to the development of excessive heat have been well studied. but simplification is particularly required in the case of those fire-alarms which are to be useful for giving intimation of a conflagration from any cause arising. as the telegraphic and telephonic wires are extended so as to traverse practically all the streets of every city, the fire-insurance companies will find it to their advantage to promote a simple plan, depending on the use of a combustible thread passing round little pulleys in the corners of all the rooms and finally out to the front, where an electrical "contact-maker" is fixed, so that on the thread being burnt and broken at any point in its circuit, an electric message will be at once sent along the nearest wire to the fire-brigade station and a bell set ringing both inside and outside the premises. somewhat similar systems will be used for checking the enterprises of the burglar. the best protected safes of the future will be enmeshed in networks of wires encased in some material which will render it impossible to determine their positions from the outside. these wires will be so related to an electric circuit that the breaking of any one of them, at any part of its course, will have the effect of ringing a bell and giving warning at the police station, as well as at other places where potential thief-catchers may be on hand. for doors and windows very simple contact devices have already been brought out, but the principal objection to their general adoption arises from the fact that so very many houses remain unconnected with any telephone system which may be made available for calling the police. even were all houses connected it is true that in some instances attempts might be made to cut the wires when a raid was in contemplation, but the risk of discovery in any such operation would prove a very powerful deterrent. in fact the telephone wire, more than any other mechanical device, is destined to aid in "improving" the burglar out of existence. with the indefinite multiplication of telephone subscribers at very cheap rates, there will come a powerful inducement towards the invention of new appliances for rendering the subscriber independent of the attention of officers at any central exchange. the duty of connecting an individual subscriber with any other with whom he may desire to converse is, after all, a purely mechanical one, and eminently of a kind which, by a combination of engineering and electrical skill, may be quite successfully accomplished. in the apparatus which will probably be in use during the twentieth century, each subscriber will have a dial carrying on its face the names and numbers of all those with whom he is in the habit of holding communication. this will be his "smaller dial," and beside it will be another, intended for only occasional use, through which, by exercising a little more patience, he may connect himself with any other subscriber whatever. corresponding dials will be fixed in the central office. under this system, when the subscriber desires to secure a connection, he moves a handle round his dial until the pointer in its circuit comes to the desired number. an electrical impulse is thus sent along the wire to the central station for every number over which the pointer passes, and the corresponding pointer or contact-maker at the central station is moved exactly in sympathy. when the correct number is reached the subscriber is in connection with the person with whom he desires to converse. if, however, the latter should be already engaged, a return impulse causes the bell of the first subscriber to ring. of course the prime cost of installing such a system as this will be greater than in the case of the simple hand-connected telephones; but the two systems can be used conjointly, and the immense convenience, especially to large firms, of being able to go straight to the parties with whom they wish to communicate, will induce many of them to adopt the automatic apparatus as soon as it has been perfected. wireless telephony must come to the front in the near future, but at first for only very special purposes. the prospect of the profits that would be attendant on working up a business unhampered by the heavy capital charges which weigh upon the owners of telephone wires must stimulate inventive enterprise to a remarkable degree in this particular line. the main difficulty, however, in the application of the system to general purposes will lie in the need for an ingenious but simple means for enabling one subscriber to call another. for this purpose probably the synchronised clock system already referred to will be found essential, each office or house being furnished with a timekeeper of this type kept in constant agreement with a central clock, and so arranged that only when the ethereal electrical impulse is given at a certain fixed point in the minute, will any particular subscriber's bell be rung. this may be effected by some such arrangement as a revolving drum, perforated at a different part of its periphery for each individual subscriber, and capable of permitting the electrical contact which makes a magnet and rings the bell only at the fraction of a moment when the subscriber's slot passes the pointer. this will mean, of course, that only at a certain almost infinitesimally small space of time in the duration of each minute will it be possible to call any particular subscriber, or rather to release the mechanism which will set his bell ringing for perhaps a minute at a time. in the presence of unscrupulous competition, resulting in the flinging out of hertzian wave vibrations promiscuously, for the purpose of destroying a rival's chances of obtaining satisfactory connections, it would be necessary to make rather more complicated arrangements of a nature analogous to those of the puzzle lock. instead of one impulse during the minute, two or three would be required, in order to release the mechanism for ringing any subscriber's bell; and no ring would take place unless the time-spaces between these impulses were exactly in accordance with the agreed form, which might be varied at convenient intervals. yet in the cases in which wireless telephony and telegraphy are taken up by local public authorities having power to forbid any one playing "dog in the manger," by preventing useful work by others while failing to promote it himself, the simpler system of wireless telephone call will be practicable. with the advance of municipalisation, and of intelligent collectivism generally, enterprises of public utility will be guarded from mere cut-throat commercial hostility much more sedulously in the twentieth century than they have been in the past. a great multitude of new applications of the telegraphic and telephonic systems will be introduced in the immediate future. not only will those subscribers who are connected by wire with central stations have the advantage of being called at any hour in the morning according to their intimated wishes, but such services as lighting the fires in winter mornings, so that rooms may be fairly warmed before they are entered, will be performed by electric messages sent from a central station. drawings will also be despatched by telegraph. for such purposes as the transmission of sketches from the scene of any stirring event, the first really practical application of drawing by telegraph will probably depend upon the use of a large number of code words divided into two groups, each of which, on the principles of co-ordinate geometry, will indicate a different degree of distance from the base line and from the side line respectively, so that from any sketch a correct message in code may be made up and the drawing may be reconstructed at the receiving end. illustrated newspapers will in this way obtain drawings exactly at the same time as their other messages, and distant occurrences will be brought before the public eye much more vividly and more correctly than has ever hitherto been practicable. for special objects, also, photographs can be sent by telegraph through the use of the photo-relief in plaster of paris, or other suitable material, which travels backwards and forwards underneath a pointer, the rising and falling of which is accurately represented by thick and thin lines--or by the darker and lighter photographic printing of a beam of light of varying intensity--at the other end, so that a shaded reproduction of the photograph is produced. relief at the sending end is in this way translated into darkness of shade at the receiving end. any general expansion of this system, if it comes, will necessarily be postponed till long after the full possibilities of the codeword plan have been exploited, because the latter works in exactly with the ordinary methods for sending telegraphic matter. the keen competition between submarine and wireless telegraphy will be one of the most exciting contests furnished by electrical progress in the first quarter of the new century. attention will be devoted to those directions on the surface of the globe in which it is possible to send messages almost entirely by land lines, and to bridge over comparatively small intervals of space from land to land by wireless telegraphy. thus the asiatic and canadian route may be expected shortly to enter into competition with the atlantic cables in telegraphic business to the united states; while australia will be reached _viâ_ singapore and java. a great impetus will be given to the wireless system as a commercial undertaking when arrangements have been perfected for causing the receiver at any particular station to translate its message into a form suitable for sending automatically. when this has been done, many of the wayside stations will be almost entirely self-working, and messages, indeed, may be despatched from island to island, or from one floating station to another across the atlantic itself. another requirement for really cheap telegraphy on the new system is a more rapid method of making the letters or signals. the irregular intervals at which the sparks from the coil of the transmitter fly from one terminal to the other render it impossible to split up the succession of flashes into intervals on the dot-and-dash principle, without providing for each dot a much longer period of time than is required for the transmission of messages on land lines. in fact the need for going slowly in the sending of the message is the principal stumbling-block which disconcerts ordinary telegraphic operators when they come to try wireless telegraphy. for remedying this defect the most hopeful outlook is in the direction of a multiplication of the pieces of apparatus for spark-making and the combining of pairs of them in such a way that, whenever the first one fails during an appreciable interval of time to emit a spark, the second is called into requisition. in this way a constant stream of sparks may be ensured, without incurring the risk of running faster than the coil will supply the electrical impulses necessary for the transmission of the message. increased rapidity in land telegraphy by the ordinary system of transmission by wire, and facility in making the records at the receiving end in easily read typewriting--these are two desiderata which at the close of the nineteenth century have been almost attained, but which will take some time to introduce to general notice. in the commercial system of the twentieth century the merchant's clerk will write his messages on a typewriter which perforates a strip of paper with holes corresponding to the various letters, while it sets down in printing, on another strip, the letters themselves. the latter will be kept as a record, but the former will be taken to the telegraph office and put through the sending machine without being read by the operator. the message will print itself at the other end and wrap itself up in secret, nothing but the address being made visible to the operator. for the use of the general public who are not possessed of the special apparatus necessary to perforate the paper another system is available. sets of movable type may be provided at the telegraph office in small compartments, the letters being on one side and indentations corresponding to the required perforations being cut or stamped into the other sides of the movable pieces. the sender of a message will set it up in a long shallow tray or "galley" like those used by printers, and he will then turn the faces of the letters downwards and see the whole passed through the machine without being read by the operator; after which he can distribute the letters if he chooses. in this way telegraphy will gradually become at once far more secret and far cheaper than it is at present, and a large amount of correspondence which at present passes through the post will be sent along the wire. many merchants will have their telephonic apparatus fitted with arrangements for setting up type or perforating strips of paper, as already described; and also with receiving apparatus for making the records in typewriting. if they fail to find a subscriber or correspondent on hand at the time when he is wanted, they can write a note to him which he will find hanging on a paper strip from his telephone when he returns. another mode of accomplishing a somewhat similar result is to provide the telephone receiver itself with a moving strip of steel, which, in its varying degrees of magnetisation, records the spoken words so that they will, at some distance of time, actuate the diaphragm of the receiver and emit spoken words. the degree of permanency which can be attained by this system is, of course, a vital point as regards its practical merits. still unsolved electrical problems are the making of a satisfactory alternate current motor suitable for running with the kind of currents generally used for electric lighting purposes--the utilisation of the glow lamp having a partial vacuum or attenuated gas for giving a cheap and soft light somewhat on the principle of the geissler tube--and last, but not least, the direct conversion of heat into electricity. with regard to the first-mentioned, the prospects have been materially altered by a discovery announced at the new york meeting of the american association for the advancement of science within a few weeks of the close of the nineteenth century. the handy and effective alternate current motor indeed seemed then as far distant as it had been in , when sir david salomons remarked, in his work on _electric light installations_ (vol. ii., p. ): "no satisfactory alternate current motor available on all circuits exists as yet, although," he added later, "the demand for such an appliance increases daily". it seems, however, that electricians have been looking in the wrong direction for the solution of using the same wire for alternate current lighting and for motive power at the same time. professor bedell, of cornell university, announced at the new york meeting referred to his discovery of the important fact that when direct and alternate currents are sent over the same line each behaves as if the other were not there, and thus the same line can be used for two distinct systems of transmitting electrical energy. no time will be lost in putting this announcement to the test, not only of scientific but also of practical verification, and the probability is that all electric lighting stations in the twentieth century will contain not only dynamos of one type for the supply of light, but also direct current generators for transmitting power in all directions over the same cables. the glow lamp having no carbon filament, but setting up a bright light with only a fraction of the resistance presented by carbon, would, if perfected, render electric lighting by far the cheapest as well as the best method of illumination. tentative work has indicated a high degree of probability that success will be achieved, and the glowing bulb is at any rate a possibility of the future which it will be well to reckon with. in reference to the conversion of heat into electricity without the intervention of machinery to provide motion, and thus to cause magnetic fields to cross one another, very little promise has yet been shown of any fundamental principle upon which a practical apparatus of the kind could be based. the electrician who works at this problem has to begin almost _de novo_, and his task is an immensely difficult one, although on every ground of analogy success certainly looks possible. in the meantime, as has already been indicated, the steam turbine and dynamo combined, working practically as a single machine for the generation of electricity, offers practically the nearest approach to direct conversion which is yet well in sight. chapter xi. warfare. the last notable war of the nineteenth century has falsified the anticipations of nearly all the makers of small arms. the magazine rifle was held to be so perfect in its trajectory, and in the rapidity with which it could discharge its convenient store of cartridges in succession, that the bayonet charge had been put outside of the region of possibility in warfare. those who reasoned thus were forgetting, to a large extent, that while small arms have been improving so also has artillery, and that a bayonet charge covered by a demoralising fire of field-pieces, mortars, and quick-firing artillery is a very different thing from one in which the assailants alone are the targets exposed to fire. given that two opposing armies are possessed of weapons of about equal capacity for striking from a distance, they may do one another a great deal of harm without coming to close quarters at all. yet victory will rest with the men who have sufficient bravery, skill and ingenuity to cross the fire-zone and tackle their enemies hand to hand. smoke-producing shells and other forms of projected cover, designed to mask the advance of cavalry and infantry, will greatly assist in the work of rendering this task of crossing the fire-zone less dangerous, notwithstanding any possible improvement that may be effected in the magazine-rifle. already it has been observed that much of the surprise and confusion which terrifies those who have no bayonets, when subjected to a cannonade and at the same time brought face to face with a bayonet charge, arises from the fact that they cannot see to shoot straight, owing to the haze produced by the smoke and its blinding effects upon the eyes. special smoke-producing shells, made for the express purpose of covering a charge, will soon be evolved from the laboratory of the chemist in pursuance of this clue. in addition to shells and other missiles, small pieces of steel-piping will be projected by mortars into the fire-swept zone, in order to supplement the defects of natural cover which, of course, are nearly always as great as possible, seeing that the ground has generally been selected by the side against which the attack is being directed. the task of enabling a rifleman to shoot straight has been taken up with extraordinary zeal and ability compared with the amount of skill and effort devoted to the corresponding or opposing object of spoiling his aim and preventing him from getting a shot in. when this latter has been to some extent accomplished, mainly by the agency of artillery, the bayonet and other weapons for use at close quarters will once more be in the ascendant. thin shields of hard steel will be affixed to the rifles of the attacking party, so as to deflect the bullets wherever possible. this baffling of the rifleman by the artillery supporting the cavalry and bayonet charge will produce momentous changes, not only in the future of war, but also in that of international relations. anything which tends to discount the value of personal bravery and to elevate the tactics of the ambuscade and the sharp-shooting expedition gives, _pro tanto_, an advantage to the meaner-spirited races of mankind, and places them more or less in a position of mastery over those who hold higher racial traditions. the man who will face the risk of being shot in the open generally belongs to a higher type of humanity than he who only shoots from behind cover. moreover, the nations which have the skill and ingenuity to manufacture new weapons of self-defence belong to a higher class than those which only acquire advanced warlike munitions by purchase. one of the early international movements of the twentieth century will be directed towards the prohibition of the sale of such weapons as magazine-rifles, quick-firing field guns, and torpedoes to any savage or barbarous race. it will be accounted as treason to civilisation for any member of the international family to permit its manufacturers to sell the latest patterns of weapons to races whose ascendency might possibly become a menace to civilisation. as factors in determining the survival of the fittest, the elements of high character, bravery, and intellectual development must be conserved in their maximum efficiency at all hazards. another potent element in the safeguards of civilisation may be seen in the increased effectiveness of weapons for coastal defence. the hideous nightmare of a barbarian irruption, such as those which almost erased culture and intellect from the face of europe during the dark ages of the fourth, fifth and sixth centuries, may occasionally be seen exercising its influence in the pessimistic writings which are from time to time issued from the press predicting the coming ascendency of the yellow man. however the case may be in regard to nations which are accessible by land to the encroachments of the asiatic, there is no doubt that those countries which are divided off by the sea have been rendered much more secure through the rapid advances which have been made in the modern appliances for defending coasts and harbours. in naval tactics, also, it will be more and more clearly seen that to possess and defend the harbours where coaling can be carried out is practically to possess and defend the trade of the high seas; and the essence of good maritime policy will be to so locate the defended harbours that they may afford the greatest amount of protection, having in view the harm that may be done by an enemy's harbours in the vicinity. the most effective naval weapon in the future will undoubtedly be the torpedo, but, like the bayonet, it requires to be in the hands of brave men before its value as the ultimate arbiter of naval conflict can be demonstrated. much fallacious teaching has arisen from what has been called the lessons of certain naval wars which occurred on the coasts of south america and china--international embroilments in which mercenaries, or only half-trained seamen and engineers, were engaged. on similar fallacious grounds it was argued that the magazine-rifle had put the bayonet out of the court of military arbitrament, and the south african war has proved conclusively how erroneous was that idea. the use of the torpedo-boat and of the weapons which it carries must always demand, like that of the bayonet, men of the strongest nerve, and of the greatest devotion to their duty and to their country. fifty miles an hour is a rate which is already in sight as the speed of the future torpedo-boat, the first turbine steamer of the british navy having achieved forty-three miles an hour before the end of the nineteenth century. it should be distinctly understood, however, that such a speed cannot be kept up for any great length of time and that long voyages are out of the question. the rôle of the turbine torpedo-boat will be to "get home" with its weapon in the shortest practicable time. hence its great value for the defence of harbours by striking at distances of perhaps two or three hours' steaming. on the high seas the battle-ships, which will virtually be the cruisers of the future, will be provided with turbine torpedo-boats, carried slung in convenient positions and ready at short notice to be let slip like greyhounds. during the hazardous run of the torpedo-boat towards the enemy, various devices will be employed for the purpose of baffling his aim, such for instance as the emission of volumes of smoke from the bows and the erection of broad network blinds covering the sight of the little craft, but capable of being shifted from side to side, so that the enemy's marksmen may never know exactly what part of the object in sight is to be aimed at. the torpedo will be carried on a mast, which at the right moment can be lowered to form a projecting spar like a bowsprit; and the explosion that will take place on its impact with the enemy's hull will be enough to blow a fatal breach in any warship afloat. for harbour defence and the safety of the battle-ship the wire-guided and propelled torpedo will form a second line behind the fast torpedo-boat. this type of weapon strikes with more unerring accuracy than any other yet included in the armoury of naval warfare, because it is under the control of the marksman from the time of its launching until it fulfils its deadly mission. its range, of course, is strictly limited; but it may be worked to advantage within the distances at which the best naval artillery can be depended upon to make good practice. the least costly and the lightest form is that in which the backward pulling of two wires, unwinding two drums on the torpedo, actuates two screws at greater or less speeds according to the rapidity of the motion imparted, any advantage of speed in one screw over the other being responded to by an alteration in the direction taken by the weapon. the torpedo may be set so as to dive from the surface at any desired interval; but, of course, an appearance in the form of at least a flash is necessary to enable the operator to judge in what direction he is sending his missile. small torpedo-boats, not manned but sticking to the surface, may be used in the same manner. each one no doubt runs a very great risk of being hit by shot or shell aimed at them; but out of half a dozen, discharged at short intervals, it would be practically impossible for an enemy to make certain that one at least did not find its billet. the submarine boat will have some useful applications in peace; but its range of utility in warfare is likely to be very limited. it is hopeless to expect the eyes of sailors to see any great distance under the water; therefore the descent must be made within sight of the enemy, who has only to surround himself with placed contact-torpedoes hanging to a depth, and to pollute the water in order to render the assault an absolutely desperate enterprise. military aeronautics, like submarine operations in naval warfare, have been somewhat overrated. visions of air-ships hovering over a doomed city and devastating it with missiles dropped from above are mere fairy tales. indeed the whole subject of aeronautics as an element in future human progress has excited far more attention than its intrinsic merits deserve. a balloon is at the mercy of the wind and must remain so, while a true flying machine, which supports itself in the air by the operation of fans or similar devices, may be interesting as a toy, but cannot have much economical importance for the future. when man has the solid earth upon which to conduct his traffic, without the necessity of overcoming the force of gravitation by costly power, he would be foolish in the extreme to attempt to abandon the advantage which this gives him, and to commit himself to such an element as the air, in which the power required to lift himself and his goods would be immeasurably greater than that needed to transport them from place to place. the amount of misdirected ingenuity that has been expended on these two problems of submarine and aerial navigation during the nineteenth century will offer one of the most curious and interesting studies to the future historian of technological progress. unfortunately that faculty of the constructive imagination upon which inventive talent depends may too frequently be indulged by its possessor without any serious reference to the question of utility. fancy paints a picture in which the inventor appears disporting himself at unheard-of depths below the surface of the sea or at extraordinary heights above the level of the land, while his friends, his rivals, and all manner of men and women besides, gaze with amazement! patent agents are only too well aware how often an inordinate desire for self-glorification goes along with real inventive talent, and how many of the brotherhood of inventors make light of the losses which may be inflicted upon trusting investors so long as they themselves may get well talked about. nations may at times be infected with this unpractical vainglory of inventiveness; and on these occasions there is need of all the restraining influence of the hard-headed business man to prevent the waste of enormous sums of money. the idea that military ascendency in the future is to be secured by the ability to fly through the air and to dive for long distances under the water has taken possession of certain sections in france, germany, russia, great britain and the united states. large numbers of voluble "boulevardiers" in paris have, during the last years of the nineteenth century, made it an article of their patriotic faith that the future success of the french navy depends upon the submarine boat. the question as to what an enemy would do with such a boat in actual warfare seems hardly ever to occur to them; and, indeed, any one who should venture to put such a query would run the risk of being set down as a traitor to his country! more important to the student of the practical details of naval preparation is the great question as to the point at which the contest between shot and armour will be brought to a standstill. that it cannot proceed indefinitely may be confidently taken for granted. the plate-makers thicken their armour while the gun-makers enlarge the size and increase the penetrative power of their weapons, until the weight that has to be carried on a battle-ship renders the attainment of speed practically impossible. meanwhile there is going forward, in the hull of the vessel itself, a gradual course of evolution which will eventually place the policy of increasing strength of armour and of guns at a discount. the division of the air-space of a warship into water-tight compartments will doubtless prove to be, in actual naval conflict, a more effectual means of keeping the vessel afloat than the indefinite increase in the thickness and consequent weight of her armour. the most advanced naval architects of modern times are bestowing more and more attention upon this feature, as affording a prospect of rendering ships unsinkable, whether through accidents or through injury in warfare. no doubt, for merchant steamers, it will be seen that development along the lines already laid down in this department will suffice for all practical purposes. the water-tight bulkheads, with readily closed or automatically shutting doorways, ensure the maintenance of buoyancy in case of any ordinary accident from collision or grounding, while the duplication of engines, shafts and propellers--without which no steamship of the middle twentieth century will be passed by marine surveyors as fit for carrying passengers on long ocean voyages--will make provision against all excepting the most extremely improbable mishaps to the machinery. if the numerical estimate of the chance of the disablement of a single engine and its propeller during a certain voyage be stated at one to a thousand, then the risk of helplessness through the break down of both systems in a vessel having twin screws and entirely separate engines will be represented by the proportion of one to a million. this mode of reckoning, of course, assumes that the two systems could be made absolutely independent in relation to all possible disasters; and some deduction must be made on account of the impossibility of attaining this ideal. yet it is evident that when every practicable device has been adopted for rendering a double accident improbable the chances against such a disaster will not be far from the proportion stated. when we come to consider the evolution of the warship as compared with that of the merchant steamer, we are at once confronted with the fact that the infliction of injury upon the boilers, the engine, or the propellers of a hostile vessel is the great object aimed at by the gunners. the evolution of the warship in the direction of ensuring safety, therefore, will not stop at the duplication of the engines, boilers and propellers. in fact it must sooner or later be apparent that the interests of a great naval power demand the working out of a type of warlike craft that shall be almost entirely destitute of armour, but constructed on such a principle--both as to hull and machinery--that she can be raked fore and aft, and shot through in all directions without becoming either water-logged or deprived of her motive power. a torpedo-boat built on this system may consist essentially of a series of steel tubes of large section grouped longitudinally, and divided into compartments like those of a bamboo cane. each of these has its own small but powerful boilers and engines, and each its separate propeller at the stern. care also is taken to place the machinery of each tube in such a position that no two are abreast. in fact, the principle of construction is such as to render just as remote as may be the possibility of any shot passing through the vessel and disabling two at the same time. if a boat of this description has each tube furnished not only with a separate screw at the stern, but also with a torpedo at the bows, it can offer a most serious menace to even the most powerful battle-ship afloat, because its power of "getting home" with a missile depends not upon its protective precautions, but upon an appeal to the law of averages, which makes it practically impossible for any gunners, however skilful, to disable all its independent sections during the run from long range to torpedo-striking distance. the attacked warship is like an animal exposed to the onslaught of one of those fabled reptiles possessing a separate life and a separate sting in each of its myriad sections; so that what would be a mortal injury to a creature having its vital organs concentrated in one spot produces only the most limited effect in diminishing its strength and powers of offence. or this class of naval fighter may be regarded as a combined fleet of small torpedo-boats, bound together for mutual purposes of offence and defence. singly, they would present defects of coal-carrying capacity, sea-going qualities, and accommodation for crew which would render them comparatively helpless and innocuous; but in combination they possess all the travelling capacities of a large warship, conjoined with the deadly powers at close quarters of a number of torpedo boats, all acting closely in concert upon a single plan. the chief naval lesson taught during the spanish-american war was the need for improving the sea-going qualities of the torpedo-boat before it can be regarded as a truly effective weapon in naval warfare. it was announced at one stage that if the spanish torpedo-boat fleet could have been coaled and re-coaled at the azores, and two or three other points on the passage across to america, it might have been brought within striking distance of the united states cruisers operating against santiago. this hypothetical statement provided but cold comfort for the spaniards, who had been persuaded to put so much of their available naval strength into a type of craft utterly unsuited for operations complying with the first great requirement of naval warfare, namely, that the proper limit of the campaign coincides with the shores of the enemy's country. but when the naval architect and the engineer have evolved a class of torpedo-using vessel which can both travel far and strike hard, and which, moreover, can stand a few well-directed shots penetrating her without succumbing to their effect, a new era will have been opened up in naval warfare--an era of high explosive weapons requiring to strike home with dash and bravery in spite of risk from shot and shell; but, like the bayonet on land, capable of overthrowing all war-machines which can only strike from a considerable distance. chapter xii. music. a perfect _sostenuto_ piano has been the dream of many a musician whose ardent desire it was to perform his music exactly as it was written. a sustained piano note is, indeed, the great mechanical desideratum for the music of the future. in music, as at present written and published for the piano, which is, and must continue to be, the real "king of instruments," there is a good deal of make-believe. a long note--or two notes tied in a certain method--is intended to be played as a continued sound, like the note of an organ; whereas there is no piano in existence which will produce anything even approximately approaching to that effect. the characteristic of the piano as an instrument is _percussion_, producing, at the moment of striking the note, a loud sound which almost immediately dies away and leaves but a faint vibration. the phonographic record of a pianoforte solo shows this very clearly to the eye, because the impression made by a long note is a deeply-marked indentation succeeded by the merest shallow scratch--not unlike the impression made by a tadpole on mud--with a big head and an attenuated body. every note marked long in pianoforte music is therefore essentially a _sforzando_ followed by a rapid _diminuendo_. anything in such music marked as a long note to be sustained _crescendo_--the most thrilling effect of orchestral, choral, and organ music--is necessarily a sham and a delusion. the genius and skill which have enabled the masters of pianoforte composition not only to cover up this defect in their instrument, but even to make amends for it, by working out effects only suitable for a percussion note, present one of the most remarkable features of musical progress in the nineteenth century. so notable is that fact in its relation to the pianoforte accompaniments of vocal music, that it seems open to question whether, even in the presence of a thoroughly satisfactory _sostenuto_ piano, much use would for many years be made of it for this particular purpose. the effects of repeated notes succeeding one another with increasing or decreasing force, and of _arpeggio_ passages, have been so fully explored and made available in standard music of every grade, that necessarily the public taste has set itself to appreciate the pianoforte solo and the accompanied song exactly as they are written and performed. these are, after all, the highest forms of music which civilisation has yet enabled one or two performers to produce. yet, in regard to solo instrumentalisation, there is no doubt that a general hope exists for the discovery of a compromise between the piano and the organ or between the piano and the string band. some inventors have aimed in the latter direction and others in the former; but no one has succeeded in really recommending his ideas to the public. combined piano-violins and piano-organs have been shown at each of the great exhibitions from the middle of the nineteenth century to its close. several of these instruments have been devised and constructed with great ingenuity; and yet practically all of them have been received by the musical profession either with indifference or with positive ridicule. the fact is that revolutionary sudden changes in musical instruments are rendered impossible owing to the near relationship which exists between each instrument and the general body of the music that is written for it. no one can divorce the two, which, as a factor in æsthetic progress, are really one and indivisible. therefore, if any man invents a musical instrument which requires for its success the sudden evolution of a new race of composers writing for it, and a new type of educated public taste to hail these composers with delight, he is asking for a miracle and he will be disappointed. what is wanted is not a new instrument, but an improved piano that shall at one and the same time correct, to some extent, the defects of the existing instrument, and leave still available all the brilliant effects which have been invented for it by a generation of musical geniuses. we want the sustained note, and yet we do not wish to lose the pretty turns and graceful devices by which the lack of it has been hidden, or atoned for, in the works of the masters. therefore our sustained note must not be too aggressive. for a long time, indeed, it must partake of the very defects which it is intended ultimately to abolish. in other words, we want to retain the percussion note with the dampers and with the loud and soft pedals, in fact, all the existing inventions for coaxing some of the notes to sustain themselves while others are cut short, as may be desired, and at the same time we have to add other and more effective means to assist the performer in achieving the same object. the more or less complicated methods aiming at the prolongation of the residual effect of the percussion have apparently been very nearly exhausted. some of the most modern pianos are really marvels of mechanical ingenuity applied to this purpose. we have now to look to something slightly resembling the principle of the violin or of the organ, in order to secure the additional _sostenuto_ effect for which we are searching. having to deal with a piano in practically its existing form, we obviously require to take special account of the fact that the note is begun by percussion, and that any attempt to bring a solid substance into contact with the wire while still vibrating, with the object of continuing its motion, is likely to produce more or less of a jarring effect. the air-blast type of note-continuer for _sostenuto_ effect therefore offers the most promising outlook for the improvement of the modern piano in the direction indicated. by directing a blast of air from a very thin nozzle on to the vibrating wire of a piano, the sound emitted may be very greatly intensified; and although naturally the decreasing amplitude of the vibration may in itself tend to create a _diminuendo_, yet it is possible to make up for this in some degree by causing the air-blast to increase in force, through the use of any suitable means, modified by an extra pedal as may be desired. delicate _pianissimo_ effects, somewhat resembling those of the eolian lyre, are produced by playing the notes with the air-blast alone, without the aid of percussion. but the louder _sostenuto_ notes depend upon the added atmospheric resistance offered by a strong current of air to those movements of the wire which have been originally set up by percussion, and the fact that this resistance gives rise to a corresponding continuance of the motion. the prolongation of a note in this way is analogous to the continual swinging of an elastic switch in a stream of water, the current by its force producing a rhythmic movement. when these eolian effects, as applied to the pianoforte, have been carefully studied, many devices for controlling them will be brought forward. the main purpose, however, must be to connect the air-blast with the percussion apparatus in such a manner that, as soon as a key is depressed, the nozzle of that particular note in the air-blast is opened exactly at the same time that the wire is struck by the hammer, and it remains open as long as the note is held down. the movement of an extra pedal, however, has the effect of throwing the whole of the air-blast apparatus out of gear and reducing the piano to a percussion instrument, pure and simple. it will be on the concert platform, no doubt, that this kind of improvement will find its first field of usefulness. performers will require, in addition to their grand pianos, reservoirs of compressed air attachable by tubes to their instruments. in private houses hydraulic air-compressors will be found more convenient. when the piano has by some such means acquired the faculty of _singing_ its notes, as well as of _ringing_ them, its ascendency, as the finest instrument adapted to solo instrumentalism, will be assured. the common domestic piano is rightly regarded by many people as being little better than an instrument of torture. one reason for this aversion is that, in the great majority of cases, the household instrument is not kept in tune. probably it is not too much to say that the man who would invent a sound cottage piano which would remain in tune would do more for the improvement of the national taste in music than the largest and finest orchestra ever assembled. the constantly vitiated sense of hearing, which is brought about by the continual jangle of notes just a fractional part of a tone out of tune, is responsible for much of the distaste for good music which prevails among the people. when the domestic instrument is but imperfectly tuned, it is natural that those pieces should be preferred which suffer least by reason of the imperfection, and these, it need hardly be remarked, generally belong to the class of music which must be rated as essentially inferior, if not vulgar. the device of winding a string round a peg and twisting it up on the latter in order to obtain tension for a vibrating note is thousands of years old. it was the method by which tension was imparted to some of the earliest harps and lyres of which history is cognisant; and it is still to be found to-day in the most elaborate and costly grand piano, with but few alterations affecting its principle of action. the pianoforte of the future will be kept in tune by more exact and scientific methods, attaining a certain balance between the thickness of the wire and the tension placed upon it by means of springs and weights. besides the ravages of the badly-tuned piano, much suffering is inflicted by the barbarous habit of permitting a sounding instrument to be used for mere mechanical exercises. the taste of the pupil is vitiated, and the nerves of other inmates of the house are subjected to a source of constant irritation when long series of notes, arranged merely as muscular exercises, and some of them violating almost every rule of musical form, are ground out hour after hour like coffee from a coffee-mill. the inconsistency of subjecting the musical ear and taste of a boy or girl to this process, and then expecting the child to develop an innate taste for the delicacies of form in melody and of the beauty of harmony, is almost as bad as would be that of asking a chinese victim of foot-binding to walk easily and gracefully. the use of the digitorium for promoting the mechanical portion of a musical education by the training of the fingers has already, to some slight extent, obviated the evils complained of. but this instrument is, as yet, only in its rudimentary stage of development. the dumb notes of the keyboard ought to be capable of emitting sounds by way of notice to the operator, in order to show when the rules have been broken. thus, for instance, the impact caused by putting a key down should have the effect of driving a small weight upwards in the direction of a metal bar, the distance of which can be adjusted. another bar, at a lower level, is also approached by a second weight, and the perfect degree of evenness in the touch is indicated by the fact that the lower bar should be made to emit a faint sound with every note, but the higher one not at all. the closer the bars the more difficult is the exercise, and remarkable evenness of touch can be acquired by a progressive training with such an instrument. the organ has been wonderfully improved during the nineteenth century. yet the decline of its popularity in comparison with the pianoforte may be accounted for on very rational grounds. while ardent organists still claim that the organ is the "king of instruments" the public generally entertain a feeling that it is a deposed king. it remains for the organ-builders of the twentieth century to attack the problem of curing its defects by methods going more directly to the root of the difficulty than any hitherto attempted. as contrasted with the pianoforte, the organ is extremely deficient in that power which the conductor of an orchestra loves to exercise--facility in accentuating and in subduing at will the work of each individual performer. for all practical purposes the ten fingers of a piano-player are the ten players in an orchestra; and, according to the force with which each finger strikes the note, is the prominence given to its effects. an air or a _motif_ may be brought out with emphasis by one set of fingers, while the others are playing an accompaniment with all sorts of delicate gradations of softness and emphasis. by multiplying the manuals, the organ-builder has endeavoured, with a certain degree of success, to make up for the unfortunate fact that the performer on his instrument possesses no similar facility in making it speak louder when he submits the note to extra pressure. one hand may be playing an air on one manual, while the second is engaged in the accompaniment on another; and the former may be connected with a louder stop, or with one of a more penetrating quality than the latter. this device, together with an elaborate arrangement of swells and pedal-notes, has greatly enlarged the capacity of the organ for producing those choral effects which mainly depend upon gradations of volume. yet the whole system, elaborate as it is, offers but a poor substitute for the marvellous range of individuality that may be expressed on the notes of the piano by instantaneous changes in the values ascribed to single notes. by the same action of his finger the pianist not only makes the note, but also gives its value; while the method of the organist is to neglect the element of finger-pressure and to rely upon other methods for imparting emphasis or softness to his work. an organ that shall emit a louder or softer note, according to the force with which the key on the manual is depressed, will no doubt be one of the musical instruments of the twentieth century. whether each key will be fitted with a resisting spring, or whether the lever will be constructed in such a way as to throw a weight to a higher or lower grade of position, according to the force with which it is struck, is a question which will depend upon the results of experiment. but the latter method is more in consonance with the conditions which have given to the piano its wonderful versatility, and it therefore seems the more probable solution of the two. upon the vigour of the finger's impact will depend the height to which a valve is thrown, and this will determine the speed and volume of the air which is liberated to rush into the pipe and make the note. the nineteenth century orchestra is a fearfully and wonderfully constructed agglomeration of ancient and modern instruments. its merits are attested by the fine musical sense of the most experienced conductors, whose aim it has been so to balance the different instruments as to produce a tastefully-blended effect, while at the same time providing for solos and also for the rendering of parts in which a small number of performers may contribute to the unfolding of the composer's ideas. the orchestra cannot therefore be examined or discussed from a mechanical point of view, however much some of the instruments of which it is composed may be thought capable of improvement. but the position of the conductor himself in the front of an orchestra is, from a purely artistic standpoint, highly anomalous. it is as if the prompter at the performance of a drama were to be seen taking the most conspicuous part and mixing among the actors upon the stage. if an orchestral piece be well played without the visible presence of a conductor, the sense of correct time reaches the audience naturally through the music itself; and any sort of gesticulations intended to mark it are under these conditions regarded as being out of place. the foremost orchestral conductors of the day are evidently impressed with this unfitness of the mechanical marking of time by the wild waving of a stick or swaying of the body; and accordingly, however much they exert themselves at the rehearsal, they purposely subdue their motions during a public performance. the time is not far distant when the object of the conductor will be to guide his band without permitting his promptings to be perceived in any way by the audience. for this purpose an "electric beat-indicator" will prove useful. various proposals for its application have been put forward, and for different purposes several of them are obviously feasible. for instance, in one system the conductor sits in a place hidden from the audience and beats time on an electric contact-maker, which admits of his sending a special message to any particular performer whenever he desires to do so. the signal which marks the time may be given to each performer, either visually by a beater concealed within a small bell-shaped cavity affixed to his desk or to his electric light; or it may be conveyed by the sense of touch through a mechanical beater within a small metal weight placed on the floor and upon which he sets one of his feet. the electric time-beater in the latter system thus taps the measure gently on the sole of the performer's foot, and special signals, as may be arranged, are sent to him by preconcerted combinations of taps. the absence of any distraction from the music itself will soon be gratefully felt by audiences, and the playing of a symphony in the twentieth century, in which the whole orchestra moves sympathetically in obedience to the "nerve-waves" of the electric current, will be the highest possible presentment of the musical art. chapter xiii. art and news. the production of pictures for the million will be practically the highest achievement of the graphic art in the twentieth century. many eminent painters do not at all relish the prospect, being strongly of opinion that when every branch of art becomes popular it will be vulgarised. this notion arises from a fallacy which has affected ideas during the nineteenth century in many matters besides art, the mistake of supposing that vulgar people all belong to one grade of society. yet every one who knows modern england, for instance, is perfectly aware that the highest standard of taste is only to be found in the elect of all classes of society. after the experience of the eighteenth century, surely it ought to have been recognised that the "upper ten thousand," when left to develop vulgarity in its true essence, can attain to a degree of perfection hardly possible in any other social grade. is there in the whole range of pictorial art anything more irredeemably vulgar than a "state portrait" by sir thomas lawrence or one of his imitators? it was under the prompting of a dread of the process of popularising art that so many eminent painters of the nineteenth century protested against the fashion set by sir j. e. millais when he sold such pictures as "cherry ripe" and "bubbles," knowing they were intended for reproduction in very large numbers by mechanical means. from a somewhat similar motive a few of the leading artists of the nineteenth century for a time stood aloof from the movement for familiarising the people with at least the form, if not the colouring, of each notable picture of the year. from small and very unpretentious beginnings, the published pictorial notes of the royal academy and other exhibitions of the year have risen to most imposing proportions; and already there is some talk of attempting a few of the best from each year's production in colours. half-tone zinco and similar processes have brought down the expenses entailed by reproductions in colour-work, so as to render an undertaking of this kind much more feasible than it was in the middle of the last half-century. "cherry ripe" cost five thousand pounds to reproduce, by the laborious processes of printing not only each colour, but almost every different shade of each colour from a different surface. in the "three-colour-zinco" process of reproduction only three printings are required, each colour with all its delicate gradations of shade being fully provided for by a single engraved block. when machines of great precision have been finally perfected for admitting of the successive blocks being printed from on paper run from the reel without any handling, a revolution will be brought about not only in artistic printing, but even in the conditions of studio work upon which the artist depends for success. first, the pictorial notes of the year will be brought out in colour; and as competition for the right of reproduction increases, the artists who have painted the most suitable and most popular pictures will find that they can get more remuneration for copyright than they can for the pictures themselves. this has already been the case in regard to a very limited number of pictures; but the exception of the past will be the rule of the future, at least as regards those pictures which possess any special merits at all. more thought will therefore be required as the motive or basis of each subject; and historical pictures will come more into favour, the affected simplicity and mental emptiness of the _plein air_ school being discarded in favour of a style which shall speak more directly to the people, and stir more deeply both their mental and their emotional natures. the artist and the printer must then confer. they can no longer afford to work in the future with such disregard of each other's ideas and methods as they have done in the past. it was at one time the custom among painters almost to despise the "black-and-white man" who drew for the press in any shape or form; but that piece of affectation has nearly been destroyed by the general ridicule with which it is now received, and by the knowledge that there are already, at the end of the nineteenth century, just as many men of talent working by methods suitable for reproduction, as there are painters who confine their attention to palette, canvas and brush. the printer will now advance a step further, and will invoke the services of the painter himself, even prescribing certain methods by which the press may be enabled to reproduce the work of the artist more faithfully than would otherwise be possible. transparency painting will no doubt be one of these methods. the artist will paint on a set of sheets of transparent celluloid or glass, mounted in frames of wood and hinged so that they can, for purposes of observation, be put aside and yet brought back to their original positions quite accurately. each different transparent sheet will be intended for one pure colour, the only pigments used being of the most transparent description obtainable. the picture may thus be built up by successive additions and alterations, not all put upon one surface, but constituting a number of "monochromes," superimposed one upon the other. when finished, each of these one-colour transparencies can then be reproduced by photo-mechanical means for multi-colour printing in the press. by what are known as the photographic "interruption" processes, a kind of converse method has achieved a certain degree of success. a landscape or a picture is photographed several times from exactly the same position, but on each occasion it is taken through a screen of a different coloured glass, which is intended for the purpose of intercepting all the rays of light, except those of one particular tint. coloured prints in transparent gelatine or other suitable medium are then made from the various negatives, each in its appropriate tint; and when all are placed together and viewed through transmitted light, the effect of the picture, with all its colours combined, is fairly well produced. more serviceable from the artistic point of view will be the method according to which the artist makes his picture by transmitted light, but the finished printed product is seen on paper, because this latter lends itself to the finest work of the artistic printer. the principal branch of the work of the photographer must continue to be portraiture. he cannot greatly reduce the cost of getting a really good negative, because so much hand-labour is required for the task of "retouching"; but he can give, perhaps, a hundred prints for the price which he now charges for a dozen, and make money by the enterprise. it has already been proved that there is no necessity for using expensive salts of gold, silver or platinum in order to secure the most artistic prints; and, as a matter of fact, some of the finest art work in the photography of the past quarter of a century has been accomplished with the cheapest of materials, such as gelatine, glue and lampblack. pigmented gelatine is, without doubt, the coming medium for photographic prints, and the methods of making them must approximate more and more closely to those of the typographic printer. by producing a "photo-relief" in gelatine--sensitised with bichromate of potash, and afterwards exposed first to the sun and then to the action of water--an impression in plastic material can be secured, from which, with the use of warm, thin, pigmented gelatine, a hundred copies or more can be printed off in a few minutes. the very general introduction of such a process has naturally been delayed owing to the extra trouble involved in the first methods which were suggested for applying it, and also, no doubt, on account of the recent fashion for platinotype and bromide of silver prints. but as soon as more convenient details for the making of pigmented gelatine prints have been elaborated, the cheapness of the material and the wonderful variety of the art shades and tints in which photographs can be executed will give the gelatine processes an advantage in the competition which it will be hopeless for other methods to challenge. the daily newspapers of a few years hence will be vividly illustrated with photographic pictures of the personages and the events of the day. the gelatine photo-relief, already alluded to, will no doubt afford the basis of the principal processes by which this will be effected. hitherto the chief drawback has been the difficulty of imparting a suitable grain to the printing blocks made from these reliefs; but this has been practically overcome by the use of sheets of metallic foil previously impressed with the form of a finely-engraved tint-block. the actual printing surface, of course, consists of an electrotype or stereotype taken from this metallic-grained photographic face. for "high-art" printing on fine paper with the more expensive kinds of ink, the half-tone zinco processes will doubtless maintain their supremacy and gradually diminish the area within which lithographic printing is required. in the case of newspaper work, however, where haste in getting ready for the press is necessarily the prime consideration, the flat and very slightly-indented surface of the zinco block is found to be unsuited to the requirements. flat blocks, which require careful "overlaying" on the machine, waste too much time for daily news work. without going into technical details it may be surmised in general terms that in the near future almost every newspaper will contain, each day, one or more photo-illustrations of events of the previous day or of the news which has come to hand from a distance. type-setting by hand is, for newspaper purposes, being so rapidly superseded, that only in the smaller towns and villages can it remain for even a few years longer. but in the machines by which this revolution has been effected, finality has been by no means reached. every line of matter which appears in any modern daily newspaper has to pass through two processes of stereotyping before it makes a beginning to effect its final work of printing upon paper. first, there is the stereotyping or casting of the line in its position in the type-setting machine after the matrices have been ranged in position by the application of the fingers to the various keys; and, secondly, when all the lines have been placed together to make a page, it is necessary to take an impression of them upon _papier mâché_, or what is technically called "flong," and then to dry it and make the full cast from it curved and ready for placing on the cylinder of the printing machine. the delay occasioned by the need for drying the wet flong is such a serious matter--particularly to evening newspapers requiring many editions during the afternoon--that several dry methods have been tried with greater or less success. but there is really no need for more than one casting process. in the twentieth century machine the matrices will be replaced by permanent type from which, when ranged in the line, an impression will be made by hard pressure on a small bar of soft metal or plastic material. all the impressed bars having been set together in a casting box having the necessary curvature, the final stereo plate for printing from will be taken at once by pouring melted metal on the combined bars. an appreciable saving, both in time and in money, will also be effected by applying the principle of the perforated strip of paper or cardboard to the purpose of operating the machine by which the necessary letters are caused to range themselves in the required order. machines similar to typewriters will be employed for perforating the strips of paper and for printing, at the same time, in ordinary letters the matter just as if it were being typewritten. the corrections can then be made by cutting off those pieces of the strips which are wrong and inserting corrected pieces in their places. no initial "justification" to the space required to make a line is needed in this system. the strips, however, are put through the setting machine, and, as they make the reading matter by the impression of bars as already described, they are divided into lines automatically. large numbers of newspapers will in future be sold from "penny-in-the-slot" machines. the system to be adopted for this particular purpose will doubtless differ in some important respects from that which has been successful in the vending of small articles such as sweetmeats and cigarettes. the newspapers may be hung on light bars within the machine, these being supported at the end by a carefully-adjusted cross piece, which, on the insertion of a penny in the slot, moves just sufficiently to permit the end of one bar with its newspaper to drop, and to precipitate the latter on to a table forming the front of the machine. when the full complement of newspapers has been exhausted the slot is automatically closed. some of the newspapers of the twentieth century will be given away gratis, and will be, for the most part, owned by the principal advertisers. this is the direction in which journalistic property is now tending, and at any juncture steps might be taken, in one or other of the great centres of newspaper enterprise, which would precipitate the ultimate movement. hardly any one who buys a half-penny paper to-day imagines for a moment that there is any actual profit on the article. it is understood on all hands that the advertisers keep the newspapers going and that the arrangement is mutually beneficial. not that either party can dictate to the other in matters outside of its own province. the effect is simply to permit the great public to purchase its news practically for the price of the paper and ink on which it is conveyed; the condition being that the said public will permit its eyes to be greeted with certain announcements placed in juxtaposition to the news and comments. sooner or later, therefore, the idea will occur to some of the leading advertisers to form a syndicate and give to the people a small broadsheet containing briefly the daily narrative. the ponderous newspapers of the latter end of the nineteenth century--filled full of enough of linotype matter to occupy more than the whole day of the subscriber in their perusal--will be to a large extent dispensed with; and the new art of journalism will consist in saying things as briefly--not as lengthily--as possible. chapter xiv. invention and collectivism. the ownership of machinery and of all the varied appliances in the evolution of which inventive genius is exercised is a matter which, strictly speaking, does not belong to the domain of this work. nevertheless, in endeavouring to forecast the progress of invention during the twentieth century, it is necessary to take count of the risks involved in the inauguration of any public and social economical systems which might tend to stifle freedom of thought and to discourage the efforts of those who have suggestions of industrial improvements to make. it is plain that those economic forces which prevent the inventor from having his ideas tested must to that extent retard the progress of industrial improvement. thousands of men, who imagine that they possess the inventive talent in a highly developed degree, are either crack-brained enthusiasts or else utterly unpractical men whose services would never be worth anything at all in the work of attacking difficult mechanical problems. it is in the task of discriminating between this class and the true inventors that many industrial organizers fail. any economic system which offers inducements to the directors of industrial enterprises to shirk the onerous, and at times very irksome, duty of sifting out the good from the bad must stand condemned not only on account of its wastefulness, but by reason of its baneful effects in the discouragement of inventive genius. considerations of this kind lead to the conclusion that during the twentieth century the spread of collectivist or socialistic ideas, and the adoption of methods of state and municipal control of production and transport may have an important bearing upon the progress of civilisation through the adoption of new inventions. many thinking men and women of the present generation are inclined to believe _the_ twentieth century invention _par excellence_ will be the bringing of all the machinery of production, transport and exchange under the official control of persons appointed by the state or by the municipality, and therefore amenable to the vote of the people. projects of collectivism are in the air, and high hopes are entertained that the twentieth century will be far more distinctively marked by the revolution which it will witness in the social and industrial organisation of the people than in the improvements effected in the mechanical and other means for extending man's powers over natural forces. the average official naturally wishes to retain his billet. that is the main motive which governs nearly all his official acts; and in the treatment which he usually accords to the inventor he shows this anxiety perhaps more clearly than in any other class of the actions of his administration. he wants to make no mistakes, but whether he ever scores a distinct and decided success is comparatively a matter of indifference to him. so long as he does not give a handle to his enemies to be used against him, he is fairly contented to go on from year to year in a humdrum style. even a man of fine feeling and progressive ideas soon experiences the numbing effects of the routine life after he has been a few years in office. he knows that he will be judged rather on the negative than on the positive principle, that is to say, for the things which it is accounted he ought not to have done rather than for the more enterprising good things which it is admitted he may have done. now any one who undertakes to encourage invention must necessarily make mistakes. he may indeed know that one case of brilliant success will make up for half a dozen comparative failures; but he reckons that at any rate the blanks in the chances which he is taking will numerically exceed the prizes. an official, however, will not dare to draw blanks. better for him to draw nothing at all. he must therefore turn his back upon the inventor and approve of nothing which has not been shown to be a great success elsewhere. this means that the socialised and municipalised enterprises must always lag behind those depending upon private effort; and the country which imposes disabilities on the latter must, for a time at least, lose its lead in the industrial race. this is what happened to england, as contrasted with the united states, when, under the influence of enthusiasm for future municipalisation, the british legislature laid heavy penalties upon those who should venture to instal electric trams in the united kingdom. the american manufacturers and tramway companies, in their keen competition with one another and perfect freedom to compete on even terms with horse traction, soon took the lead in all matters pertaining to electric traction, and the british public, at the close of the nineteenth century, have had to witness the humiliating spectacle of their own public authorities being forced to import electrical apparatus, and even steam-engines applicable to dynamos used for tramway purposes, from the other side of the atlantic! the lesson thus enforced will not in the end be missed, although it may require a considerable time to be fully understood. officialism is a foe to inventive progress; and whether it exists under a regime of collectivism or under one of autocracy, it must paralyse industrial enterprise to that extent, thus rendering the country which has adopted it liable to be outstripped by its competitors. the true friend of inventive progress is generally the rising competitor in a busy hive of industry where the difficulties of securing a profitable footing are very considerable. such a man is ever on the watch for an opportunity to gain some leverage by which he may raise himself to a level with older-established or richer competitors. if he be a good employer his workmen enter into the spirit of the competition, feeling that promotion will follow on any services they may render. they may perhaps possess the inventive talent themselves, or they may do even greater services by recognising it in others and co-operating in their work. it is thus that successful inventions are usually started on their useful careers. it is therefore upon private enterprise that the principal onus of advancing the inventions which will contribute to the progress of the human race in the twentieth century must necessarily fall. the type of man who will cheerfully work _pro bono publico_, with just as much ardour as he would exhibit when labouring to advance his own interests, may already be found here and there in civilised communities at existing stages of development; but it is not sufficiently numerous to enable the world to dispense with the powerful stimulus of competition. just as a superior type of machinery can be elaborated during the course of a single century, there is no doubt that--mainly through the use of improved appliances for lessening the amount of brute force which man needs to exert in his daily avocations--the nervous organisations of the men and women constituting the rank and file during the latter part of the twentieth century will be immensely improved in sensitiveness. a corresponding advance will then take place in the capacity for collectivism. but a human being of the high class demanded for the carrying out of any scheme of state socialism must be bred by a slow improvement during successive generations. a hundred years do not constitute a long period of time in the process of the organic evolution of the human race, and, as tennyson declared, we are far from the noon of man-- there is time for the race to grow. yet the public advantages of collectivist activities in certain particular directions cannot for a moment be denied. much waste and heavy loss are entailed by the duplication of works of general utility by rival owners, each of them, perhaps, only half utilising the full capacities of his machinery or of the other plant upon which capital has been expended. moreover, as soon as companies have become so large that their managers and other officials are brought into no closer personal relations with the shareholders than the town clerks, engineers, and surveyors of cities, and the departmental heads of state bureaus are associated with the voters and ratepayers, the systems of private and of collective ownership begin to stand much more nearly on a par as regards the non-encouragement which they offer to inventiveness. one of the greatest discoveries of the twentieth century, therefore, will be the adoption of a _via media_ which will admit of the progressiveness of private ownership in promoting industrial inventions, combined with the political progressiveness of collectivism. one direction in which an important factor assisting in the solution of this problem is to be expected is in the removal of the causes which tend to make public officials so timid and unprogressive. so long as a mere temporary outcry about the apparent non-success of some adopted improvement--whose real value perhaps cannot be proved unless by the exercise of patience--may result in the dismissal or in the disrating of the official who has recommended it, just so long will all those who are called upon to act as guides to public enterprises be compelled to stick to the most conservative lines in the exercise of their duties. more assurance of permanence in positions of public administration is needed. the man upon whose shoulders rests the responsibility of adopting, or of condemning, new proposals brought before him, ostensibly in the interests of the public welfare, ought to be regarded as being called upon to carry out _quasi_-judicial functions; and his tenure of office, and his claim to a pension after a busy career, ought not to depend upon the chances of the evanescent politics of the day. if a man has proved, by his close and successful application to the study of his profession--as evinced in the tests which he has passed as a youth and during his subsequent career in subordinate positions--that he is really a lover of hard work, and imbued with conscientious devotion to duty, he may generally be trusted, when he has attained to a position of superintendence, to do his utmost in the interests of the public whom he serves. this is the theory upon which the appointment of a judge in almost any english-speaking community is understood to be made; and, although failures in its application may occur now and then, there is no doubt whatever that on the average of cases it works out well in practice. if private manufacturers, whose success in life depends upon their appreciation of talent and inventiveness, could be assured that in dealing with public officials they would be brought into contact with men of the standing indicated, instead of being confronted so frequently with the demand for commissions and other kinds of solatium on account of the risks undertaken in recommending anything new, they would soon largely modify their distrust of what is known as collectivism. it is the duty of the public whose servant an official is, rather than of the private manufacturer, to insure him against the danger of losing his position on account of any possible mistake in the exercise of his judgment. in short, the day is not far distant when the men upon whom devolves the responsibility of examining into, and reporting upon, the claims of those who profess to have made important industrial improvements will be looked upon as exercising judicial functions of the very highest type. when the important reforms arising from this recognition have been introduced, the forces of collectivism will cease to range themselves on the side of stolid conservatism in industry, as they undoubtedly have done in the nineteenth century even while they inconsistently professed to advance the cause of progress politically. the inventor, who in the early part of the nineteenth century was generally denounced as a public enemy, will, in the latter part of the twentieth century, be hailed as a benefactor to the community, because he will be judged by the ultimate, rather than by the immediate, effects of his work, and because it will be the duty of the public authorities to see to it that the dislocation of one industry incidental the promotion of another by any invention does not, on the whole, operate to throw people out of employment, but, on the contrary, gives more constant work and better wages to all. but the slow progress of the fundamental traits of human nature will retard the attainment of this goal. the world has a long distance to travel in the uphill road of industrial and social improvement before it can succeed in obtaining a really true view of the part fulfilled by inventive genius in contributing to human happiness. the aberdeen university press limited. a classified catalogue of scientific works published by messrs. longmans, green, & co. london: paternoster row, e.c. new york: & fifth avenue. bombay: hornby road. contents. page _advanced science manuals_ agriculture astronomy bacteriology biology botany and gardening building construction chemistry dynamics electricity _elementary science manuals_ engineering geology health and hygiene heat hydrostatics light _london science class-books_ _longmans' civil engineering series_ machine drawing and design magnetism manufactures mechanics medicine and surgery metallurgy mineralogy natural history and general science naval architecture navigation optics photography physics physiography physiology _practical elementary science series_ _proctor's (r. a.) works_ sound statics steam, oil and gas engines strength of materials technology telegraphy telephone _text-books of science_ thermodynamics _tyndall's (john) works_ veterinary medicine, etc. workshop appliances zoology chemistry. _crookes._--select methods in chemical analysis, chiefly inorganic. by sir william crookes, f.r.s., etc. third edition, rewritten and enlarged. with woodcuts. vo., _s._ net. _furneaux._--elementary chemistry, inorganic and organic. by w. furneaux, f.r.g.s., lecturer on chemistry, london school board. with illustrations and experiments. crown vo., _s._ _d._ _garrett and harden._--an elementary course of practical organic chemistry. by f. c. garrett, m.sc. (vict. et dunelm.), assistant lecturer and demonstrator in chemistry, the durham college of science, newcastle-on-tyne; and arthur harden, m.sc. (vict.), ph.d., assistant lecturer and demonstrator in chemistry, the owens college, manchester. with illustrations. crown vo., _s._ _jago._--works by w. jago, f.c.s., f.i.c. inorganic chemistry, theoretical and practical. with an introduction to the principles of chemical analysis inorganic and organic. with woodcuts and numerous questions and exercises. fcp. vo., _s._ _d._ an introduction to practical inorganic chemistry. crown vo., _s._ _d._ inorganic chemistry, theoretical and practical. a manual for students in advanced classes of the science and art department. with plate of spectra and woodcuts. crown vo., _s._ _d._ _kolbe._--a short text-book of inorganic chemistry. by dr. hermann kolbe. translated and edited by t. s. humpidge, ph.d. with illustrations. crown vo., _s._ _d._ _mendelÉeff._--the principles of chemistry. by d. mendelÉeff. translated from the russian (sixth edition) by george kamensky, a.r.s.m., of the imperial mint, st. petersburg; and edited by t. a. lawson, b.sc, ph.d., fellow of the institute of chemistry. with diagrams and illustrations. vols. vo., _s._ _meyer._--outlines of theoretical chemistry. by lothar meyer, professor of chemistry in the university of tübingen. translated by professors p. phillips bedson, d.sc., and w. carleton williams, b.sc. vo., _s._ _miller._--introduction to the study of inorganic chemistry. by w. allen miller, m.d., ll.d. with woodcuts, fcp. vo., _s._ _d._ _muir._--a course of practical chemistry. by m. m. p. muir, m.a., fellow and prælector in chemistry of gonville and caius college, cambridge. ( parts.) part i. elementary. crown vo., _s._ _d._ part ii. intermediate. crown vo., _s._ _d._ part iii. 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(vict.), ph.d., f.r.s., professor of chemistry in the royal college of science, south kensington. assisted by eminent contributors. a dictionary of applied chemistry. vols. vo. vols. i. and ii., _s._ each. vol. iii., _s._ quantitative chemical analysis. with woodcuts. fcp. vo., _s._ _d._ _thorpe and muir._--qualitative chemical analysis and laboratory practice. by t. e. thorpe, c.b., ph.d., d.sc., f.r.s., and m. m. pattison muir, m.a. with plate of spectra and woodcuts. fcp. vo., _s._ _d._ _tilden._--works by william a. tilden, d.sc. london, f.r.s., professor of chemistry in the royal college of science, south kensington. a short history of the progress of scientific chemistry in our own times. crown vo., _s._ net. introduction to the study of chemical philosophy. the principles of theoretical and systematic chemistry. with woodcuts. with or without the answers of problems. fcp. vo., _s._ _d._ practical chemistry. the principles of qualitative analysis. fcp. vo., _s._ _d._ hints on the teaching of elementary chemistry in schools and science classes. with illustrations. crown vo., _s._ _watts'_ dictionary of chemistry. revised and entirely rewritten by h. forster morley, m.a., d.sc., fellow of, and lately assistant professor of chemistry in, university college, london; and m. m. pattison muir, m.a., f.r.s.e., fellow, and prælector in chemistry, of gonville and caius college, cambridge. assisted by eminent contributors. vols. vo. vols. i. and ii., _s._ each. vol. iii., _s._ vol. iv., _s._ _whiteley._--works by r. lloyd whiteley, f.i.c., principal of the municipal science school, west bromwich. chemical calculations. with explanatory notes, problems and answers, specially adapted for use in colleges and science schools. with a preface by professor f. clowes, d.sc. (lond.), f.i.c. crown vo., _s._ organic chemistry: the fatty compounds. with illustrations. crown vo., _s._ _d._ physics, etc. _ganot._--works by professor ganot. translated and edited by e. atkinson, ph.d., f.c.s. elementary treatise on physics, experimental and applied. with coloured plates and maps, and woodcuts, and appendix of problems and examples with answers. crown vo., _s._ natural philosophy for general readers and young persons. with plates, woodcuts, and an appendix of questions. crown vo., _s._ _d._ _glazebrook and shaw._--practical physics. by r. t. glazebrook, m.a., f.r.s., and w. n. shaw, m.a. with woodcuts. fcp. vo., _s._ _d._ _guthrie._--molecular physics and sound. by f. guthrie, ph.d. with diagrams. fcp. vo., _s._ _d._ _helmholtz._--popular lectures on scientific subjects. by hermann von helmholtz. translated by e. atkinson, ph.d., f.c.s., formerly professor of experimental science, staff college. with illustrations. vols., crown vo., _s._ _d._ each. contents.--vol. i.--the relation of natural science to science in general--goethe's scientific researches--the physiological causes of harmony in music--ice and glaciers--the interaction of the natural forces--the recent progress of the theory of vision--the conservation of force--the aim and progress of physical science. contents.--vol. ii.--gustav magnus. in memoriam--the origin and significance of geometrical axioms--the relation of optics to painting--the origin of the planetary system--thought in medicine--academic freedom in german universities--hermann von helmholtz--an autobiographical sketch. _henderson._--elementary physics. by john henderson, d.sc. (edin.), a.i.e.e., physics department, borough road polytechnic. crown vo., _s._ _d._ _maclean._--exercises in natural philosophy. by magnus maclean, d.sc., professor of electrical engineering at the glasgow and west of scotland technical college. crown vo., _s._ _d._ _meyer._--the kinetic theory of gases. elementary treatise, with mathematical appendices. by dr. oskar emil meyer, professor of physics at the university of breslau. second revised edition. translated by robert e. baynes, m.a., student of christ church, oxford, and dr. lee's reader in physics. vo., _s._ net. _van 'thoff._--the arrangement of atoms in space. by j. h. van t'hoff. second, revised, and enlarged edition. with a preface by johannes wislicenus, professor of chemistry at the university of leipzig; and an appendix 'stereo-chemistry among inorganic substances,' by alfred werner, professor of chemistry at the university of zürich. translated and edited by arnold eiloart. crown vo., _s._ _d._ _watson._--works by w. watson, b.sc., assistant professor of physics in the royal college of science, london; assistant examiner in physics, science and art department. elementary practical physics: a laboratory manual for use in organised science schools. with illustrations and exercises. crown vo., _s._ _d._ a text-book of physics. with diagrams and illustrations. large crown vo., _s._ _d._ _worthington._--a first course of physical laboratory practice. containing experiments. by a. m. worthington, m.a., f.r.s. with illustrations. crown vo., _s._ _d._ _wright._--elementary physics. by mark r. wright, m.a., professor of normal education, durham college of science. with illustrations. crown vo., _s._ _d._ mechanics, dynamics, statics, hydrostatics, etc. _ball._--a class-book of mechanics. by sir r. s. ball, ll.d. diagrams. fcp. vo., _s._ _d._ _geldard._--statics and dynamics. by c. geldard, m.a., formerly scholar of trinity college, cambridge. crown vo., _s._ _goodeve._--works by t. m. goodeve, m.a., formerly professor of mechanics at the normal school of science, and the royal school of mines. the elements of mechanism. with woodcuts. crown vo., _s._ principles of mechanics. with woodcuts and numerous examples. crown vo., _s._ a manual of mechanics: an elementary text-book for students of applied mechanics. with illustrations and diagrams and examples taken from the science department examination papers, with answers. fcp. vo., _s._ _d._ _goodman._--mechanics applied to engineering. by john goodman, wh. sch., a.m.i.c.e., m.i.m.e., professor of engineering in the yorkshire college, leeds (victoria university). with illustrations and numerous examples. crown vo., _s._ _d._ net. _grieve._--lessons in elementary mechanics. by w. h. grieve, late engineer, r.n., science demonstrator for the london school board, etc. stage . with illustrations and a large number of examples. fcp. vo., _s._ _d._ stage . with illustrations. fcp. vo., _s._ _d._ stage . with illustrations. fcp. vo., _s._ _magnus._--works by sir philip magnus, b.sc., b.a. lessons in elementary mechanics. introductory to the study of physical science. designed for the use of schools, and of candidates for the london matriculation and other examinations. with numerous exercises, examples, examination questions, and solutions, etc., from - . with answers, and woodcuts. fcp. vo., _s._ _d._ key for the use of teachers only, price _s._ - / _d._ hydrostatics and pneumatics. fcp. vo., _s._ _d._; or, with answers, _s._ the worked solutions of the problems, _s._ _robinson._--works by the rev. j. l. robinson, m.a. elements of dynamics (kinetics and statics). with numerous exercises. a text-book for junior students. crown vo., _s._ a first book in statics and dynamics. with numerous examples and answers. crown vo, _s._ _d._ sold separately: statics, _s._; dynamics, _s._ _smith._--works by j. hamblin smith, m.a. elementary statics. crown vo., _s._ elementary hydrostatics. crown vo., _s._ key to statics and hydrostatics. crown vo., _s._ _tarleton._--an introduction to the mathematical theory of attraction. by francis a. tarleton, ll.d., sc.d., fellow of trinity college, and professor of natural philosophy in the university of dublin. crown vo., _s._ _d._ _taylor._--works by j. e. taylor, m.a., b.sc. (lond.). theoretical mechanics, including hydrostatics and pneumatics. with diagrams and illustrations, and examination questions and answers. crown vo., _s._ _d._ theoretical mechanics--solids. with illustrations, worked examples and over examples from examination papers, etc. crown vo., _s._ _d._ theoretical mechanics.--fluids. with illustrations, numerous worked examples, and about examples from examination papers, etc. crown vo., _s._ _d._ _thornton._--theoretical mechanics--solids. including kinematics, statics and kinetics. by arthur thornton, m.a., f.r.a.s. with illustrations, worked examples, and over examples from examination papers, etc. crown vo., _s._ _d._ _twisden._--works by the rev. john f. twisden, m.a. practical mechanics; an elementary introduction to their study. with exercises, and figures and diagrams. crown vo., _s._ _d._ theoretical mechanics. with examples, numerous exercises, and diagrams. crown vo., _s._ _d._ _williamson._--introduction to the mathematical theory of the stress and strain of elastic solids. by benjamin williamson, d.sc., f.r.s. crown vo., _s._ _williamson and tarleton._--an elementary treatise on dynamics. containing applications to thermodynamics, with numerous examples. by benjamin williamson, d.sc., f.r.s., and francis a. tarleton, ll.d. crown vo., _s._ _d._ _worthington._--dynamics of rotation: an elementary introduction to rigid dynamics. by a. m. worthington, m.a., f.r.s. crown vo., _s._ _d._ optics and photography. _abney._--a treatise on photography. by sir william de wiveleslie abney, k.c.b., f.r.s., principal assistant secretary of the secondary department of the board of education. with woodcuts. fcp. vo., _s._ _d._ _glazebrook._--physical optics. by r. t. glazebrook, m.a., f.r.s., principal of university college, liverpool. with woodcuts of apparatus, etc. fcp. vo., _s._ _wright._--optical projection: a treatise on the use of the lantern in exhibition and scientific demonstration. by lewis wright, author of 'light: a course of experimental optics'. with illustrations. crown vo., _s._ sound, light, heat, and thermodynamics. _cumming._--heat treated experimentally. by linnÆus cumming, m.a. with illustrations. crown vo., _s._ _d._ _day._--numerical examples in heat. by r. e. day, m.a. fcp. vo., _s._ _d._ _emtage._--light. by w. t. a. emtage, m.a. with illustrations. crown vo., _s._ _helmholtz._--on the sensations of tone as a physiological basis for the theory of music. by hermann von helmholtz. royal vo., _s._ _madan._--an elementary text-book on heat for the use of schools. by h. g. madan, m.a., f.c.s., fellow of queen's college, oxford; 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author of 'telephone lines and their properties,' etc. with full-page illustrations and diagrams. crown vo., _s._ _d._ _preece and sivewright._--telegraphy. by sir w. h. preece, k.c.b., f.r.s., v.p.inst., c.e., etc., engineer-in-chief and electrician, post office telegraphs; and sir j. sivewright, k.c.m.g., general manager, south african telegraphs. with illustrations. fcp. vo., _s._ engineering, strength of materials, etc. _anderson._--the strength of materials and structures: the strength of materials as depending on their quality and as ascertained by testing apparatus. by sir j. anderson, c.e., ll.d., f.r.s.e. with woodcuts. fcp. vo., _s._ _d._ _barry._--railway appliances: a description of details of railway construction subsequent to the completion of the earthworks and structures. by sir john wolfe barry, k.c.b., f.r.s., m.i.c.e. with woodcuts. fcp. vo., _s._ _d._ _goodman._--mechanics applied to engineering. by john goodman, wh.sch., a.m.i.c.e., m.i.m.e., professor of engineering in the yorkshire college, leeds (victoria university). with illustrations and numerous examples. crown vo., _s._ _d._ net. _low._--a pocket-book for mechanical engineers. by david allan low (whitworth scholar), m.i.mech.e., professor of engineering, east london technical college (people's palace), london. with over specially prepared illustrations. fcp. vo., gilt edges, rounded corners, _s._ _d._ _smith._--graphics, or the art of calculation by drawing lines, applied especially to mechanical engineering. by robert h. smith, professor of engineering, mason college, birmingham. part i. with separate atlas of plates containing diagrams. vo., _s._ _stoney._--the theory of stresses in girders and similar structures; 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(two volumes.) vol. i., with portrait and a reminiscence of the author, plates, and numerous illustrations. crown vo., _s._ vol. ii., with numerous illustrations. crown vo., _s._ _d._ works by richard a. proctor. the moon: her motions, aspect, scenery, and physical condition. with many plates and charts, wood engravings, and lunar photographs. crown vo., _s._ _d._ other worlds than ours: the plurality of worlds studied under the light of recent scientific researches. with illustrations; map, charts, etc. crown vo., _s._ _d._ our place among infinities: a series of essays contrasting our little abode in space and time with the infinities around us. crown vo., _s._ _d._ myths and marvels of astronomy. crown vo., _s._ _d._ light science for leisure hours: familiar essays on scientific subjects, natural phenomena, etc. vols. i. and ii. crown vo., _s._ each. vol. i. cheap edition. crown vo., _s._ _d._ the orbs around us; essays on the moon and planets, meteors and comets, the sun and coloured pairs of suns. crown vo., _s._ _d._ the expanse of heaven: essays on the wonders of the firmament. crown vo., _s._ _d._ other suns than ours: a series of essays on suns--old, young, and dead. with other science gleanings. two essays on whist, and correspondence with sir john herschel. with star-maps and diagrams. crown vo., _s._ _d._ half-hours with the telescope: a popular guide to the use of the telescope as a means of amusement and instruction. with plates. fcp. vo., _s._ _d._ new star atlas for the library, the school, and the observatory, in twelve circular maps (with two index-plates). with an introduction on the study of the stars. illustrated by diagrams. cr. vo., _s._ the southern skies: a plain and easy guide to the constellations of the southern hemisphere. showing in maps the position of the principal star-groups night after night throughout the year. with an introduction and a separate explanation of each map. true for every year. to., _s._ half-hours with the stars: a plain and easy guide to the knowledge of the constellations. showing in maps the position of the principal star-groups night after night throughout the year. with introduction and a separate explanation of each map. true for every year. to., _s._ _d._ larger star atlas for observers and students. in twelve circular maps, showing stars, double stars, nebulæ, etc. with index-plates. folio, _s._ the stars in their seasons: an easy guide to a knowledge of the star-groups. in large maps. imperial vo., _s._ rough ways made smooth. familiar essays on scientific subjects. crown vo., _s._ _d._ pleasant ways in science. crown vo., _s._ _d._ nature studies. by r. a. proctor, grant allen, a. wilson, t. foster, and e. clodd. crown vo., _s._ _d._ leisure readings. by r. a. proctor, e. clodd, a. wilson, t. foster, and a. c. ranyard. crown vo., _s._ _d._ physiography and geology. _bird._--works by charles bird, b.a. elementary geology. with geological map of the british isles, and illustrations. crown vo., _s._ _d._ advanced geology. a manual for students in advanced classes and for general readers. with over illustrations, a geological map of the british isles (coloured), and a set of questions for examination. crown vo., _s._ _d._ _green._--physical geology for students and general readers. by a. h. green, m.a., f.g.s. with illustrations. vo., _s._ _morgan._--elementary physiography. treated experimentally. by alex. morgan, m.a., d.sc., f.r.s.e., lecturer in mathematics and science, church of scotland training college, edinburgh. with maps and diagrams. crown vo., _s._ _d._ _thornton._--works by j. thornton, m.a. elementary practical physiography. part i. with illustrations. crown vo., _s._ _d._ part ii. with illustrations. crown vo., _s._ _d._ elementary physiography: an introduction to the study of nature. with maps and illustrations. with appendix on astronomical instruments and measurements. crown vo., _s._ _d._ advanced physiography. with maps and illustrations. crown vo., _s._ _d._ natural history and general science. _beddard._--the structure and classification of birds. by frank e. beddard, m.a., f.r.s., prosector and vice-secretary of the zoological society of london. with illustrations. vo., _s._ net. _furneaux._--works by william furneaux, f.r.g.s. the outdoor world; or, the young collector's hand-book. with plates, of which are coloured, and illustrations in the text. crown vo., _s._ net. life in ponds and streams. with coloured plates and illustrations in the text. crown vo., _s._ net. butterflies and moths (british). with coloured plates and illustrations in the text. crown vo., _s._ net. _hudson._--british birds. by w. h. hudson, c.m.z.s. with coloured plates from original drawings by a. thorburn, and plates and figures by c. e. lodge, and illustrations from photographs. crown vo., _s._ net. _nansen._--the norwegian north polar expedition, - : scientific results. edited by fridtjof nansen. volume i. with plates and numerous illustrations in the text. demy to, _s._ net. contents: . colin archer: the _fram_-- . j. f. pompeckj: the jurassic fauna of cape flora. with a geological sketch of cape flora and its neighbourhood by fridtjof nansen-- . a. g. nathorst: fossil plants from franz josef land-- . r. collett and f. nansen: an account of the birds-- . g. o. sars: crustacea. *** _the aim of this report (which will be published in english only) is to give, in a series of separate memoirs, a complete account of the scientific results of the norwegian polar expedition, - . the whole work is estimated to form five or six quarto volumes, which it is hoped will be finished in the course of about two years._ _stanley._--a familiar history of birds. by e. stanley, d.d., formerly bishop of norwich. with illustrations. crown vo, _s._ _d._ manufactures, technology, etc. _bell._--jacquard weaving and designing. by f. t. bell. with diagrams. vo., _s._ net. _calder._--the prevention of factory accidents: being an account of manufacturing industry and accident, and a practical guide to the law on the safe-guarding, safe-working and safe-construction of factory machinery, plant and premises. by john calder, sometime her majesty's inspector of factories for the north of scotland. with tables and illustrations. crown vo., _s._ _d._ net. _lupton._--mining. an elementary treatise on the getting of minerals. by arnold lupton, m.i.c.e., f.g.s., etc. with diagrams and illustrations. crown vo., _s._ net. _morris and wilkinson._--the elements of cotton spinning. by john morris and f. wilkinson. with a preface by sir b. a. dobson, c.e., m.i.m.e. with diagrams and illustrations. crown vo., _s._ _d._ net. _sharp._--bicycles and tricycles: an elementary treatise on their design and construction. with examples and tables. by archibald sharp, b.sc. with illustrations and diagrams. cr. vo., _s._ _taylor._--cotton weaving and designing. by john t. taylor. with diagrams. crown vo., _s._ _d._ net. _watts._--an introductory manual for sugar growers. by francis watts, f.c.s., f.i.c. with illustrations. crown vo., _s._ health and hygiene. _ashby._--health in the nursery. by henry ashby, m.d., f.r.c.p., physician to the manchester children's hospital, and lecturer on the diseases of children at the owens college. with illustrations. crown vo., _s._ _d._ _buckton._--health in the house; twenty-five lectures on elementary physiology. by mrs. c. m. buckton. with woodcuts and diagrams. crown vo., _s._ _corfield._--the laws of health. by w. h. corfield, m.a., m.d. fcp. vo., _s._ _d._ _notter and firth._--works by j. l. notter, m.a., m.d., and r. h. firth, f.r.c.s. hygiene. with illustrations. crown vo., _s._ _d._ practical domestic hygiene. with illustrations. crown vo., _s._ _d._ _poore._--works by george vivian poore, m.d. essays on rural hygiene. crown vo., _s._ _d._ the dwelling-house. with illustrations. crown vo., _s._ _d._ _wilson._--a manual of health-science: adapted for use in schools and colleges. by andrew wilson, f.r.s.e., f.l.s., etc. with illustrations. crown vo., _s._ _d._ medicine and surgery. _ashby and wright._--the diseases of children, medical and surgical. by henry ashby, m.d., lond., f.r.c.p., physician to the general hospital for sick children, manchester; and g. a. wright, b.a., m.b. oxon., f.r.c.s., eng., assistant-surgeon to the manchester royal infirmary, and surgeon to the children's hospital. enlarged and improved edition. with illustrations. vo., _s._ _bennett._--works by william h. bennett, f.r.c.s., surgeon to st. george's hospital; 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and f. f. burghard, m.d. and m.s., f.r.c.s., teacher of practical surgery in king's college, london, surgeon to king's college, hospital (lond.), etc. part i. the treatment of general surgical diseases, including inflammation, suppuration, ulceration, gangrene, wounds and their complications, infective diseases and tumours; the administration of anæsthetics. with illustrations. royal vo., _s._ _d._ [ready. part ii. the treatment of the surgical affections of the tissues, including the skin and subcutaneous tissues, the nails, the lymphatic vessels and glands, the fasciæ, bursæ, muscles, tendons and tendon-sheaths, nerves, arteries and veins. deformities. with illustrations. royal vo., _s._ [ready. part iii. the treatment of the surgical affections of the bones. amputations. with illustrations. royal vo., _s._ part iv. the treatment of the surgical affections of the joints (including excisions) and the spine. with illustrations. royal vo., _s._ _other parts are in preparation._ _clarke._--works by j. jackson clarke, m.b. lond., f.r.c.s., assistant surgeon at the north-west london and city orthopædic hospitals, etc. surgical pathology and principles. with illustrations. crown vo., _s._ _d._ post-mortem examinations in medico-legal and ordinary cases. with special chapters on the legal aspects of post-mortems, and on certificates of death. fcp. vo., _s._ _d._ _coats._--a manual of pathology. by joseph coats, m.d., late professor of pathology in the university of glasgow. fourth edition. revised throughout and edited by lewis r. sutherland, m. d., professor of pathology, university of st. andrews. with illustrations. vo., _s._ _d._ _cooke._--works by thomas cook, f.r.c.s. eng., b.a., b.sc., m.d., paris. tablets of anatomy. being a synopsis of demonstrations given in the westminster hospital medical school. eleventh edition in three parts, thoroughly brought up to date, and with over illustrations from all the best sources, british and foreign. post to. part i. the bones. _s._ _d._ net. part ii. limbs, abdomen, pelvis. _s._ _d._ net. part iii. head and neck, thorax, brain. _s._ _d._ net. aphorisms in applied anatomy and operative surgery. including typical _vivâ voce_ questions on surface marking, etc. crown vo., _s._ _d._ dissection guides. aiming at extending and facilitating such practical work in anatomy as will be specially useful in connection with an ordinary hospital curriculum. vo., _s._ _d._ _curtis._--the essentials of practical bacteriology: an elementary laboratory book for students and practitioners. by h. j. curtis, b.s. and m.d. lond., f.r.c.s., late surgical registrar, university college hospital; 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a treatise on surgical injuries, diseases, and operations. by sir john eric erichsen, bart., f.r.s., ll.d. edin., hon. m.ch. and f.r.c.s. ireland. illustrated by nearly engravings on wood. vols. royal vo., _s._ _fowler and godlee._--the diseases of the lungs. by james kingston fowler, m.a., m.d., f.r.c.p., physician to the middlesex hospital and to the hospital for consumption and diseases of the chest, brompton, etc.; and rickman john godlee, m.s., f.r.c.s., fellow and professor of clinical surgery, university college, london, etc.; with illustrations. vo., _s._ _garrod._--works by sir alfred baring garrod, m.d., f.r.s., etc. a treatise on gout and rheumatic gout (rheumatoid arthritis). with plates, comprising figures ( coloured), and illustrations engraved on wood. vo., _s._ the essentials of materia medica and therapeutics. crown vo., _s._ _d._ _goodsall and miles._--diseases of the anus and rectum. by d. h. goodsall, f.r.c.s., senior surgeon, metropolitan hospital; senior surgeon (late house surgeon), st. mark's hospital; 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(lond.), f.g.s. with over illustrations, a geological map of the british isles (coloured), and a set of questions for examination. crown vo., _s._ _d._ human physiology: a manual for students in advanced classes of the science and art department. by john thornton, m.a. with illustrations, some of which are coloured, and a set of questions for examination. crown vo., _s._ physiography. by john thornton, m.a. with maps, illustrations, and coloured plate of spectra. crown vo., _s._ _d._ agriculture. by henry j. webb, ph.d., b.sc. with illustrations. crown vo., _s._ _d._ net. hygiene. by j. lane notter, m.a., m.d., professor of hygiene in the army medical school, netley, colonel, royal army medical corps; and r. h. firth, f.r.c.s., late assistant professor of hygiene in the army medical school, netley, major, royal army medical corps. with illustrations. crown vo., _s._ _d._ elementary science manuals. *** _written specially to meet the requirements of the elementary stage of science subjects as laid down in the syllabus of the directory of the science and art department._ practical, plane, and solid geometry, including graphic arithmetic. by i. h. morris. fully illustrated with drawings. crown vo., _s._ _d._ geometrical drawing for art students. embracing plane geometry and its applications, the use of scales, and the plans and elevations of solids, as required for the examinations of the science and art department. by i. h. morris. crown vo., _s._ _d._ text-book on practical, solid, or descriptive geometry. by david allan low (whitworth scholar). part i. crown vo., _s._ part ii. crown vo., _s._ an introduction to machine drawing and design. by david allan low. with illustrations. crown vo., _s._ _d._ building construction and drawing. by edward j. burrell. with illustrations and working drawings. crown vo., _s._ _d._ an elementary course of mathematics. containing arithmetic; euclid (book i., with deductions and exercises); and algebra. crown vo., _s._ _d._ theoretical mechanics. including hydrostatics and pneumatics. by j. e. taylor, m.a., b.sc. with numerous examples and answers, and diagrams and illustrations. crown vo., _s._ _d._ theoretical mechanics--solids. by j. e. taylor, m.a., b.sc. (lond.). with illustrations, worked examples, and over examples from examination papers, etc. crown vo., _s._ _d._ theoretical mechanics--fluids. by j. e. taylor, m.a., b.sc. (lond.). with illustrations, numerous worked examples, and about examples from examination papers, etc. crown vo., _s._ _d._ a manual of mechanics. with illustrations and diagrams, and examples taken from examination papers, with answers. by t. m. goodeve, m.a. crown vo., _s._ _d._ sound, light, and heat. by mark r. wright, m.a. with diagrams and illustrations. crown vo., _s._ _d._ metallurgy: an elementary text-book. by e. l. rhead. with illustrations. crown vo., _s._ _d._ physics. alternative course. by mark r. wright, m.a. with illustrations. crown vo., _s._ _d._ magnetism and electricity. by a. w. poyser, m.a. with illustrations. crown vo., _s._ _d._ organic chemistry: the fatty compounds. by r. lloyd whiteley, f.i.c., f.c.s. with illustrations. crown vo., _s._ _d._ inorganic chemistry, theoretical and practical. by william jago, f.c.s., f.i.c. with illustrations and numerous questions and exercises. fcp. vo., _s._ _d._ an introduction to practical inorganic chemistry. by william jago, f.c.s., f.i.c. crown vo., _s._ _d._ practical chemistry: the principles of qualitative analysis. by william a. tilden, d.sc. fcp. vo., _s._ _d._ elementary inorganic chemistry. by william furneaux, f.r.g.s. crown vo., _s._ _d._ elementary geology. by charles bird, b.a., f.g.s. with coloured geological map of the british islands, and illustrations. crown vo., _s._ _d._ human physiology. by william furneaux, f.r.g.s. with illustrations. crown vo., _s._ _d._ a course of practical elementary biology. by j. bidgood, b.sc. with illustrations. crown vo., _s._ _d._ elementary botany, theoretical and practical. by henry edmonds, b.sc. with illustrations. crown vo., _s._ _d._ steam. by william ripper, member of the institution of mechanical engineers. with illustrations. crown vo., _s._ _d._ elementary physiography. by j. thornton, m.a. with maps and illustrations. with appendix on astronomical instruments and measurements. crown vo., _s._ _d._ agriculture. by henry j. webb, ph.d. with illustrations. crown vo., _s._ _d._ the london science class-books. edited by g. carey foster, f.r.s., and by sir philip magnus, b.sc., b.a., of the city and guilds of london institute. astronomy. by sir robert stawell ball, ll.d., f.r.s. with diagrams. fcp. vo., _s._ _d._ mechanics. by sir robert stawell ball, ll.d., f.r.s. with diagrams. fcp. vo., _s._ _d._ the laws of health. by w. h. corfield, m.a., m.d., f.r.c.p. with illustrations. fcp. vo., _s._ _d._ molecular physics and sound. by frederick guthrie, f.r.s. with diagrams. fcp. vo., _s._ _d._ geometry, congruent figures. by o. henrici, ph.d., f.r.s. with diagrams. fcp. vo., _s._ _d._ zoology of the invertebrate animals. by alexander macalister, m.d. with diagrams. fcp. vo., _s._ _d._ zoology of the vertebrate animals. by alexander macalister, m.d. with diagrams. fcp. vo., _s._ _d._ hydrostatics and pneumatics. by sir philip magnus, b.sc., b.a. with diagrams. fcp. vo., _s._ _d._ (to be had also _with answers_, _s._) the worked solutions of the problems, _s._ botany. outlines of the classification of plants. by w. r. mcnab, m.d. with diagrams. fcp. vo., _s._ _d._ botany. outlines of morphology and physiology. by w. r. mcnab, m.d. with diagrams. fcp. vo., _s._ _d._ thermodynamics. by richard wormell, m.a., d.sc. with diagrams. fcp. vo., _s._ _d._ practical elementary science series. elementary practical physiography. (section i.) by john thornton, m.a., head master of the central higher grade school, bolton. with illustrations and a coloured spectrum. crown vo., _s._ _d._ elementary practical physiography. (section ii.). a course of lessons and experiments in elementary science for the queen's scholarship examination. by john thornton, m.a. with illustrations and a series of questions. crown vo., _s._ _d._ practical domestic hygiene. by j. lane notter, m.a., m.d., professor of hygiene in the army medical school, netley, etc.; and r. h. firth, f.r.c.s., late assistant professor of hygiene in the army medical school, netley, etc. with illustrations. crown vo., _s._ _d._ practical mathematics. by a. g. cracknell, m.a., b.sc. crown vo., _s._ _d._ a practical introduction to the study of botany: flowering plants. by j. bretland farmer, f.r.s., m.a., professor of botany in the royal college of science, london. with illustrations. crown vo., _s._ _d._ elementary practical chemistry. by g. s. newth, f.i.c., f.c.s., demonstrator in the royal college of science, london, etc. with illustrations and experiments. crown vo., _s._ _d._ elementary practical physics. by w. watson, b.sc., assistant professor of physics in the royal college of science, london, etc. with illustrations and exercises. crown vo., _s._ _d._ elementary practical zoology. by frank e. beddard, m.a. oxon., f.r.s., prosector to the zoological society of london. with illustrations. crown vo., _s._ _d._ _other volumes in preparation._ transcriber's notes . passages in italics are surrounded by _underscores_. . the word pharmacopoeia uses an oe ligature in the original. . minor changes were made for the purpose of consistency in the book list at the end, like adding period, etc. . the following misprints have been corrected: "sufficiemt" corrected to "sufficient" (page ) changed "--" to "-" in nitrogen-fixing (page ) joined words "intel lectual" split over two lines (page ) missing text "to" added after "incidental" (page ) . other than the corrections listed above, printer's inconsistencies in spelling, punctuation and hyphenation have been retained. proofreading team at www.pgdp.net [illustration] scientific american supplement no. new york, september , scientific american supplement. vol. xxiv., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. page i. biography.--the new statue of philip lebon.--biography of the french pioneer inventor of gas lighting, with notes on the recent inauguration of his statue.-- illustration. ii. chemistry.--the analysis of urine.--an elaborate investigation of the method of analyzing chemically and microscopically this fluid, with illustrations of the apparatus employed.-- illustrations iii. electricity.--electrical alarm for pharmacists.--an apparatus for indicating to the pharmacist when he removes from the shelf a bottle containing poison.-- illustrations. electric steel railways.--by george w. mansfield.--a full discussion of the problem of electric railways; comparison with horse and cable traction. iv. engineering.--improved oscillating hydraulic motor.--a small motor for household use, as for driving sewing machines and other domestic machinery.-- illustrations. the ceara harbor works.--a remarkable engineering work now in progress in brazil; the formation of an artificial harbor.-- illustrations. v. geology.--notes of a recent visit to some of the petroleum-producing territories of the united states and canada.--by boverton redwood, f.i.c., f.c.s.--the second portion of this valuable paper, treating more particularly of canadian petroleum. vi. meteorology.--the "meteorologiske institut" at upsala, and cloud measurements.--the methods used and results attained in the famous upsala observatory under profs. ekholm and hagström; the measurement of clouds.-- illustration. vii. miscellaneous.--drawing instrument for accurate work.--by j. lehrke.--a magnifying instrument for fine work and measurements.-- illustrations. liquid and gaseous rings.--notes on the production of vortex rings.--the different aspects and breaking up of smoke rings.-- illustrations. scenes among the extinct volcanoes of rhineland.--the picturesque features of the geological formations of this region described.-- illustrations. shall we have a national horse?--an eloquent plea by randolph huntington for the production of a good type of animal.--use of the arabian horse as an improver of the breed. viii. naval engineering.--trial trip of the ohio.--the remarkable results attained by the introduction of new boilers and machinery in an american steamship. ix. physiology.--apparatus for determining mechanically the reaction period of hearing.--an interesting study of the time of transmission of an impulse through the sensor and motor nerves.-- illustration. x. sanitation.--a new disinfector.--description of a new apparatus for disinfecting by superheated steam and air, with tabular statement of elaborate tests made with it.-- illustrations. trees from a sanitary aspect.--by charles roberts, f.r.c.s., etc.--the sanitary value of trees considered by this eminent sanitarian.--the uses and abuses of shade near houses. xi. technology.--a new alkali process.--the parnell & simpson process of making carbonate of soda, combining the features of the leblanc and ammonia methods. a new process for the distillation and concentration of chemical liquids.--by george anderson, of london.--an apparatus and process especially adapted to the manufacture of sulphate of ammonia.--the invention of alex. angus croll described.-- illustration. barlow's machine for moulding candles.--a new apparatus for candle manufacture, fully described and illustrated.-- illustrations. temperature of gas distillation.--the mooted question discussed by mr. wm. foulis, the eminent gas engineer. the largest black ash furnace in the world.--note of a recent furnace for use in the leblanc process of soda manufacture. * * * * * improved oscillating hydraulic motor. the motor of mm. schaltenbrand & moller is adapted for use for household purposes, where small power is required, as in driving sewing machines. fig. shows the motor with all its parts in side elevation, the flywheel and head rest being in section. fig. is a side view, with the air reservoir and distribution valve in section through the line - . figs. and represent the same apparatus, but without support, as where it is to be used on the table of a sewing machine, with the crank of the motor directly fastened to the flywheel of the sewing machine. fig. is a plan or horizontal section at the level of the line - , and fig. is a section passing through the same line, but only including the cylinder and axis of the distributing valve. fig. is a horizontal section of the button of the cock through the line - of fig. . finally, fig. shows in detail, plan, and elevation the arrangement of the starting valve. [illustration: figs. through improved oscillating hydraulic motor.] this little motor does not show any new principle. it uses the old oscillating cylinder, but it embraces in its construction ingenious details which render its application very simple and very easy, especially, as we have already said, to sewing machines. in the first place, the oscillating bronze cylinder, a, is cast in one piece with the distribution cock, _a_, fig. , and its seat, _b_, also of bronze, is adjusted and fastened by means of the screw, _b_, to the air reservoir, c', cast with its cistern, c, acting as foundation or bed plate for the motor. this cistern is held either on the base of the cast iron bearing frame, d, of the main shaft, _d_, _d_, figs. and , or directly on the sewing machine table, figs. and , by means of two pins, _e_ and _e'_, so that it can oscillate about an axis which is perpendicular to the shaft, _d_, to which is attached the disk, f, carrying the crank. this arrangement of parts, in combination with the horizontal axis of the distribution valve and with the piston rod, _g_, considered as a vertical axis of rotation, forms a species of universal joint between the crank pin and the table, so that it can be put in place without adjustment by any workman, who only has to screw up the two screws, _h_, to fasten to the table the standard, e, and the piece, e', in which are screwed the pivots, _e_ and _e'_, which support the tank, and this all the rest of the motor. as is seen more clearly in fig. , the water under pressure enters by the pipe, _c_, to which is attached a small tube of india rubber, and leaves by the pipe, _c'_, and is carried away by another india rubber tube. the openings of the distribution cock are symmetrically pierced in the seat and plug, which latter is divided internally by a horizontal diaphragm so arranged that at each oscillation communication is established alternately above and below the piston. so that it can be started or stopped quickly, the opening and closing of the throttle valve, _i_ (fig. ), is effected by a single pulling movement upon the handle, i, and this draws out the valve horizontally. for this end the lever is pivoted upon the extremity of the valve stem, and ends in a bar engaging with a fork which acts as its fulcrum. this fork is cast in one piece with the plug, j, which closes the opening through which the valve is put in place, as shown in detail in fig. . to prevent the lever from spinning out of the fork when it is pulled or pushed, this lever is prevented from turning by the valve stem, provided for this purpose with a double rib, _i'_ (figs. and ), which engages in slots in one piece, _j_, secured in the interior of the plug, j. lest the friction of the conical distribution valve oscillating with the cylinder should occasion a loss of power, care is taken to leave the key free in its seat, _b_, by not forcing the pivot, _k_ (figs. , , and ), whose position in its seat is regulated by the screw, _k'_. it follows that a very slight escape of water may be produced, but that does no harm, as it is caught in the reservoir, c, provided with a little pipe, k (figs. and ), to carry it away. to maintain proper relations between the pressure of the water, or the work it is called upon to do, and the motor, the quantity of water introduced into the cylinder at each stroke of the piston is regulated by adjusting the length of stroke by the crank pin. for this end the course of the latter is made variable by means of the piece, _f_, adjusted by set-screw in the interior of the disk, f (figs. and ), and tapped for the reception of a screw terminated by a milled button, _f_. if this button is turned, it moves the piece, _f_, and therefore regulates the distance of the crank pin, _g'_, to which the piston rod, _g_, is attached (fig. ) from the center of rotation. when the motor is arranged as shown in figs. and , or for the transmission of motion by means of a band wheel, _p_, cast in one with the flywheel, p, the disk which receives the crank pin of variable position is fixed directly upon the axle, _d_, of the same flywheel carried by the support, d; but when the motor can be applied directly, as is the case for example in the singer sewing machine, upon the axle of the machine, no support is used, and the arrangement shown in figs. and is adopted. in this case the disk, f', is cast with three arms which serve, by means of a screw, to fasten it to the flywheel carried by the axle of the sewing machine. when the motor is used on the upper stories of buildings, the changes of speed incidental to drawing the water from the lower stories from the same pipe can be compensated by the use of an accumulator. this accessory apparatus is composed of a reservoir of a capacity of liters or more, intercalated in the pipe which supplies the motor, so that the water coming from the principal pipe enters the bottom of this reservoir, passing through an india rubber valve opening inward, the supply for the motor coming through a tube always open and placed above this valve. the air trapped in the accumulator is compressed by the water, and when the pressure in the pipe decreases, the valve closes and the compressed air drives the water through the motor with decreasing pressure until normal pressure is re-established in the pipes.--_publication industrielle._ * * * * * trial trip of the ohio. some important trials of the new machinery of the screw steamer ohio, belonging to the international navigation company, have recently taken place on the clyde. the ohio is an american built steamer measuring ft. by ft. by ft. in., and of , tons gross. she has been entirely refitted with new engines and boilers by messrs. james howden & co., glasgow, who also rearranged the bunker, machinery, and hold spaces, so as to give the important advantage of increased cargo accommodation obtainable from the use of their improved machinery, which occupies considerably less space than the engines and boilers of the same power which have been replaced. the new engines are of the triple expansion type, and the boilers, which are designed for supplying steam of lb. pressure, are worked on howden's system of forced draught, which combines increased power with high economy in fuel. the object of the owners in refitting the ohio was to test the capability and economy of this system of forced draught on a sufficient scale to guide them in dealing with steamships of the largest class and great power. in the refit of the ohio the boilers were designed to work with a very moderate air pressure, this being sufficient for the power required by the contract. the combined power and economy, however, guaranteed by messrs. howden & co. for the use of their system of forced draught was higher than has hitherto been attempted in any steamship, and sufficient, if attained, to prove the large reduction that could safely be made in the number and size of boilers for the use of the system, and the quantity of coal required to produce a given power. the contract for the refit of the steamer required that , indicated horse power (which was the maximum power of the engines removed) should be maintained during the trial on a consumption of . lb. of coal per indicated horse power per hour. originally the boilers of the ohio, from which this power was produced, were three in number, double ended, ft. in. in diameter by ft. in. in length, having each six furnaces ft. in diameter, or eighteen furnaces in all, with an aggregate fire grate area of square feet. the new boilers, fitted with the forced draught, are likewise three in number, but single ended, ft. in diameter by ft. in. in length, having each three furnaces ft. in. in diameter, or nine furnaces in all, with an aggregate fire grate area of square feet. air for combustion is supplied to the boilers by one of messrs. w.h. allen & co.'s fans, ft. in. in diameter, driven direct by an engine having a cylinder in. in diameter with stroke of in. the boilers removed had two stoke holds across the ship, one fore and one aft of the boilers, while the new boilers have only one stoke hold on the after side. the engines removed have cylinders in. and in. in diameter by in. stroke, while the new engines have three cylinders in., in., and in. in diameter respectively, with piston stroke of in. during the trials the coals were weighed out under the supervision of the officers of the company, who also took the record of speed and other data. after running down channel for a considerable time, the trial on the coals weighed out began, and lasted hours minutes, during which time , lb. of welsh coal were burned, the trial ending with the same revolutions of engines and the same pressure in boilers with which it began. the mean indicated horse power, calculated from the mean of seven sets of indicator cards, taken during the trial, and the mean revolutions per minute, found by dividing the total revolutions recorded on the engine counter by the minutes in the period of the trial, amounted to , , thus making the consumption . lb. per indicated horse power per hour, and the power per square foot of fire grate almost exactly indicated horse power. while testing the indicated horse power and consumption of coal, the steamer ran to and fro between the cloch and cumbrae lights, and also made several runs on the measured mile at skelmorlie, from which the mean speed of the vessel was found to be . knots per hour. the remarkably high results obtained were most satisfactory to the representatives of the owners, and a large party of experts on board congratulated mr. howden on the successful fulfillment of the onerous guarantees undertaken.--_engineering._ * * * * * the ceara harbor works. the works illustrated by the engravings are now being constructed under a concession from the imperial government of brazil. the province of ceara has an area of about , square miles, and is one of the richest in brazil. its produce comprises sugar, coffee, cocoa, cotton, tobacco, spices, fruit, cabinet and dye woods, india rubber, etc. its population at the last census, taken in , amounted to , inhabitants, that of the capital, the city and port of ceara, being about , . although ceara is the principal seaport at which lines of english, french, american, brazilian, and other steamers regularly call, prior to the commencement of the harbor improvements it was almost an open roadstead, passengers and goods having to be conveyed by lighters and boats between vessels and the shore. the official statistics of the trade and shipping of the port show that an income of £ , per annum will be collected by the ceara harbor corporation from the dues which they are authorized by their concession to charge on all imports and exports and on the vessels using the port and from the rent of the bonded warehouses. [illustration: new harbor works, ceara, brazil.] the drawings given here show the nature of the works, which are of a simple character. the depth of water along the principal quay, which is being constructed of solid concrete, and is connected with the shore by an iron and steel viaduct over ft. in length--which is already completed--will be ft. at low water and ft. at high. this quay and breakwater is shown in perspective, in plan, and in section, and is of a very heavy section, as will be gathered by the scale given immediately below it. meanwhile the landing of cargo is temporarily carried on at the end of the viaduct, which at high tide has a depth of about ft. of water. the custom house and bonded warehouses are being built of the fine granite obtained at the monguba quarries, which adjoin the baturite railway, about sixteen miles from the port. a new incline has also been constructed from the rail way down to the port. the line has been laid along the viaduct, and will be extended over the quays as soon as they are completed. the concrete, of which a large quantity is being used, is mixed by carey & latham's patent mixers, and the contractors have supplied the very large and complete plant for carrying out the operations. the engineer to the corporation is mr. r.e. wilson, m. inst. c.e., westminster, and his resident at ceara is mr. r.t.h. saunders, m. inst. c.e. the contractors for the work are messrs. punchard, mctaggart & co., their representative at ceara being mr. george wilson, m. inst. c.e._--the engineer._ * * * * * electric street railroads. by george w. mansfield. why should we prefer electricity as the propelling agent of our street cars over all other known methods? i answer, without hesitation, because it is the best, and being the best is the cheapest. briefly i will present the grounds upon which i take my stand. to-day the only methods for tramway service are three in number: horses, with a history of fifty years and over; cables, with a history of fifteen years; and electricity, with a history of two years. i give the latter two years on the basis of the oldest electric street railroad in existence to-day, and that is the baltimore railroad, equipped with the daft system. the main points for consideration common to each are six in number: st. obtaining of franchise. d. construction of buildings, viz., engine house or stable. d. equipment--rolling stock, horses, engines and dynamos. th. construction of tramway. th. cost of operation. th. individual characteristics and advantages. each of these requires a paper by itself, but in as concise a way as possible, presenting only the salient reasons and figures, i shall endeavor to embody it in one. st. obtaining of franchise. i assume the municipal officers and the promoters honest men. it is the universal settled conviction that a street car propelled with certainty and promptness by mechanical means is infinitely to be preferred to horses. hence, if this guarantee can be given, there need be no fear from the other side of the house. years of experience prove that this guarantee can be given. the mechanical methods are electricity and the cable. to suit local conditions the former has three general applications--overhead, underground, and accumulator systems; while the latter has but one, the underground. hence, the former, electricity, has three chances to the latter's one to meet the whims, opinions, or decisions of municipal authorities. other advantages accruing from mechanical methods are cleaner streets, absence of noise, quick time, no blockades, no stables accumulating filth and breeding pestilence, and lastly the great moral sympathetic feeling for man's most faithful and valuable servant, the horse. these all are directly in favor of obtaining the right franchise. the three general ways of obtaining the same are a definite payment of cash to the authorities, a guarantee of an annual payment of a certain per cent. of the earnings, and lastly a combination of the two. for the city or town the latter way is the safest, and the best, all things considered. as electricity is mechanical, and as it can be shown that it is the cheapest to construct and most economical, and has three chances to operate, it stands by far the most likely to obtain the franchise. d. construction of buildings. the governing factors under this head are the local land valuation and tax. the system necessitating a spread eagle policy on the land question will cost. what could be a more perfect illustration than the horse railroad system? the motive power of the new york central railroad between new york and albany could be comfortably stowed in the barns of some of the new york city street railways. what a contrast! the real estate, buildings, and fixtures of the third ave. line are valued at $ , , , and what buildings! cattle sheds in the metropolis of america. surely they did not cost a tithe of this great sum. what did? the land, a whole block and more. henry george advocates might find food for thought here. all this is true of the other lines in every city in the union. enormous expenditures for land. a good one half of their capital sunk in purchasing the necessary room. go where you will, a good fifty per cent. of the capital is used for land for their stables. this obviously does not include equipment. how is it with mechanical systems? the land is one of the minor considerations, the last thing considered. let us look at some figures. from careful examination of many engine plants, considering the ratio between a certain number of horses with their necessary adjuncts and a steam plant of numerically equal power, i find it stands as to . that is, a steam plant complete of horse power capacity would need only one thirtieth the floor space of thirty horses. with larger powers this ratio is still greater, and from one estimate i found that it stood as to , i.e., for horses i should have to have times more floor space than for an equal number of mechanical horse power. it must be remembered also that the mechanical horse power is per cent. greater than the best animal horsepower. from one maker, taking the engine alone, i found that a rated horse power engine, guaranteed in every particular, would have ample room in the stall for one horse in the average stable. another instance showed that i could get a steam plant complete, engine, boiler, etc., of horse power, in a space by feet, which is smaller than the average stall. here is shown the enormous saving in land purchase. for car room a building several stories high would answer perfectly, since quick-hoisting elevators could be put in and the tracks on each floor have wire connections with the dynamos, so that the cars could be run across the floor to where you please, facilitating storage and dispensing with handling. this would not be possible with the cable. comparing electricity and cable on this point, all things favor the former clearly and beyond all question. furthermore, if locality so favored, the subject of land purchase for electricity could be tabooed entirely, since distance can be so readily overcome. way out in the suburbs or back in the country by the side of some waterfall, your station might be, while the current is sent to the great city over heavy conductors. here land rent or tax would be at the minimum. with horses or cable plainly proximity must be had. it is estimated that the land occupied by the madison avenue line of new york city is worth the cost of miles of ordinary double track. d. equipment at station and rolling stock. the rolling stock would be in each case approximately the same. consisting of cars of equal seating capacity, the difference of cost would be the necessary attachments for the mechanical systems. a first class foot horse car costs $ , ; a first class foot cable car costs about $ , ; and a first class foot electric car costs about $ , . rates: electricity, ; horse, . ; cable, . . i believe, however, that the mechanical system is bound to work material changes in car construction, in fact it is almost imperative. in all probability a car with to per cent. greater seating capacity than the horse car can be constructed on a different plan for the price given for the electric car. this price, it must be noted, is the one for attachment of motor to the present horse car. the horse cars produced to-day are most carefully planned, thoroughly built, and admirably adapted to their service, but the inexorable law of progress decrees their extinction, for something better. motive power. to represent clearly the costs, etc., of the three systems under this head, let us assume a road. take, if you please, a double line miles long, and operating cars with speed of miles an hour, and running hours out of . this would call for horses on the track and horses in the stables, or a total of horses; at $ , counting harness, etc., this would cost $ , . with electricity we will proceed as follows: the weight of car with passengers and motor attachments would be about , lb. it is easily calculated that to propel the same at the specified rate on a level would take about . horse power, a total of horse power. to make allowances for grades we can calculate that, if the entire road was one gradient of three per cent., each car would take about . horse power, or since only are going up, a total of . horse power. it will be fair now to take the average of these two, or . horse power for an average road. allowing per cent. loss from engine to work done in actually propelling car, we would have to have . horse power. allowing a good safety factor, it would be well to put in a horse power plant. this would cost complete $ , ; necessary dynamos, $ , . among these figures should be counted cost of conductor of sufficient size to allow of but three per cent. in energy to overcome its resistance. this i have calculated using a potential of volts; and find that the total cost of six miles copper conductor is $ , with above conditions. the total cost is now seen to be $ , . as to cables, since the recovery of energy available for tractive purposes is but percent., then the engine of horse power represents what must be had. allowing a generous factor of safety, let us say that a is all sufficient. this would cost complete and erected about $ , . the cable would cost $ . , and gears, etc., $ , , making a total of $ , . the ratio of the three systems stands: electricity, ; cable, . ; horse, . . th. construction of tramway. figures upon this point must necessarily be either averages or approximations. the nature of the locality socially, naturally, and we grieve to say it, politically, has a strong influence upon its construction. estimating on single track only, a horse road would cost as an average $ , per mile. with electricity we have several methods we can avail ourselves of: surface, costing about $ , ; overhead double conductor, $ . ; underground, $ , . with cable but one method, the underground, is possible. this cost is variously estimated at from $ , to $ , per mile; however, the latter figure is excessive. a fair average would be $ , . the ratio of constructions could be fairly placed as follows, putting electricity as , by taking the average of the three methods at $ , : horse road, . ; cable, . . unquestionably a great majority of roads of the past have not been constructions of engineering, and of all places requiring care, skill, and engineering, the street roads are the places. th. cost of operation. a fair figure for cost of one horse for one year is $ . for electricity, allowing per cent. loss in transmission, etc., . horsepower would be the work done by engine to get horse power on the track. there are to-day plenty of steam plants producing horse power for work at from $ to $ per annum. take the average, $ . with electricity then $ would well represent the price of producing . horsepower. with cable these figures would hold true, but more work is required. a greater loss is entailed. since but per cent. is recovered, the figure for horse power on the track would be . horse power. at the above rates this would be $ per horse power per year. our ratio here is: electricity, ; cables, . ; horses, . . this is by no means the whole of the story, for just here must we compute the depreciation and hence repairs due to time. let us take the road figured on heretofore, and make three tables. in the following i have under each system taken the estimated costs, allowed a fair per cent. for depreciation, summed up and obtained the ratios. any figure then like interest, etc., which would not affect ratios, i have omitted. electricity. conductors, per cent. $ . engine and dynamos, per cent. . cars, per cent. , . roadway, per cent. , . ----------- total. $ , . horses. horses and appurtenances, per cent. $ , . cars, per cent. , . roadway, etc., per cent. , . ----------- total. $ , . cables. cable, per cent. $ , . engine and boiler, etc., per cent. , . cars, per cent. , . roadway, per cent. , . ------------ total. $ , . these totals put in ratio are as follows: electricity, ; cable, . ; and horses, . . placing all the ratios obtained in a table, we have the following: electricity. horses. cables. depreciation. . . operating expenses. . . construction of tramway. . . motors, cars, etc. . . cars. . . --- ---- ---- totals. . . average. . . now this table must stand by itself for what it represents, and no more. it will be noted that i have not introduced the subject of men. this would unquestionably show favorably for both electricity and cable. again, note, please, that this table does not represent your profits exactly as per ratios. i have to get them operated the same number of cars and under the same headway. now with either electricity or cable a higher rate of speed can be maintained with but a very small proportionate increase of cost. this means quicker time, more trips, and greater receipts. evidently, as a financial investment, even if cost of maintenance and operating is greater, the cable is to be preferred to horses. how is it with electricity? the ratios of expenses, etc., stand for themselves, the law of speed is far simpler than with cable, bringing even greater receipts, and again in practice the saving of coal in proportion to work done on track day or night is immensely more economical than with the cable. this point will be touched upon later. th. individual characteristics and advantages. under this head a few of the salient features of each system will be mentioned. as the possibilities and limitations of the horse railroad system are, however, so well known, it is needless to go over them. i therefore will confine myself to the electric and cable systems. with electricity single track lines, crooked streets, all descriptions of turnouts, crossings, branches, etc., are as easy to construct and operate as with horses. with the cable system they are either impossible or enormously expensive. with electricity the line is not a unit, so that the complete stoppage of the whole line is absolutely impossible. with cable it is a unit and it is possible. with electricity the life of the conductor is infinite; with cable, two years. with electricity, and the improvements now being made in traction wheels, etc., the heaviest grades are as easily surmounted as with the cable; although it is true that for grades exceptional in character, such as per cent. grades or over, i should be willing to give the contract to cable. with electricity any speed can be attained by the individual cars. they are absolutely independent. lost time can be made up, etc. with cable the cars are dependent upon speed of cable. lost time cannot be made up except on down grades. with electricity work done by engine is synchronous with work done on the track at any time of the day or night, with the loss of per cent. due to the conversions in each case. in other words, for every horse power of useful work done on track the engine does . horse power. this ratio is constant. it makes no difference whether or horse power of work is necessary on the track, the engine has but to do per cent. in excess. with cable, if horse power of work is all that is required on the track, the engine may be doing horse power to get that amount there through the gears and cable. with heavier loads this is somewhat diminished, but about the very best figure that can be put forth is but per cent. recovery, with per cent. loss--the exact converse of electricity under heavy loads.--_street railway journal._ * * * * * electrical alarm for pharmacies. [illustration: fig. .] to avoid the errors which sometimes occur in a pharmacy or in a laboratory, where one bottle is taken for another, especially in the case of those containing highly poisonous or dangerous substances, a simple arrangement, shown in the cuts, has been proposed. the apparatus, in principle, is a species of electrical alarm, in circuit with an ordinary house telegraph line. it consists essentially, as shown in fig. , of a battery, bell, and pedestal, provided with an electric contact on which the flask rests. fig. shows this contact or break piece. on a series of pedestals thus arranged and intercalated in the same circuit the flasks containing poisonous or dangerous substances, whose inadvertent handling might cause trouble, are placed. in removing one of these flasks the circuit is closed, and the electric bell notifies the pharmacist of the danger attendant on the use of the substances contained in the flask referred to, thus guarding against the errors due to carelessness, and quite too frequent, especially in pharmacies.--_chronica cientifica._ [illustration: fig. .] * * * * * apparatus for determining mechanically the reaction period of hearing. the following apparatus, constructed after the designs of dr. loeb, assistant in the physiological institute at wurzburg, is for the purpose of measuring the reaction period of hearing, that is, the period which elapses between the time when a sound wave affects the auditory nerve and is thence transferred to the brain, then affecting the consciousness, and the moment when the motor nerves can be thrown into action by the will. it is, therefore, necessary to fix both instants--when the sound is produced and when the observer has, from its warning, received the impulse so as to press down a key. the great advantage of this instrument over others adapted for the same end consists in this, that the determination in its essentials is effected entirely by mechanism, and, therefore, the graphic results attained by it are free from all sources of error, which errors other methods always introduce to a greater or less extent. thus its results are quite unexceptionable. [illustration: reaction period of hearing.] the apparatus shown in the cut rests on three feet, two of them consisting of strong screws, so that by aid of the circular level, _l_, on the base plate, it can be adjusted perfectly level. on a little shelf attached to a square rod, seen on the left of the instrument, rising from the base plate, and near its top, is a horizontal tube, through which, by a bulb not shown in the cut, a blast of air can be blown. in front of the other opening of the tube is a horizontal fork of ebonite, whose arms carry on the side opposite the tube a metallic ball. through the arms of the fork pass the wires of the circuit of an electric battery. these terminate in two rounded ends, which, when the arms approach each other, are touched by the metallic ball, so that the latter also closes the metallic circuit. by the blast of air a wooden wedge contained in the tube is driven between the arms of the fork, the ball falls from them, and the electric stream is cut off. the ball drops upon the inclined metallic plate, _p_, bounces off it, and is received in a little sack, s. when the observer hears the ball strike the plate, he presses on the key, _t_, and the interval between the two instants, namely, the falling of the ball upon the plate and the pressing of the key, _t_, is what is to be mechanically fixed and measured. the electric current, which is closed by the ball as long as it lies on the jaws of the fork, flows around the arms of the electro-magnet, _m_, which continually attracts an armature fastened to a lever arm, and coming over the poles of the magnet. if the circuit is broken by the fall of the ball, the armature at once rises upward. by this a spring contained in the tube, _g_, and hitherto kept compressed, is released, which gives a shock to the right angled frame, _a a_, containing a blackened or smoked plate of glass, so that, following the wire, _b_, acting as a guide, the plate flies from left to right of the apparatus. to prevent the plate from recoiling, a catch, _d_, is fastened to the side bar, _c_. furthermore, lest the friction of the wire, _b_, in the guiding apertures of the frame should impair its velocity as it moves from left to right, it is connected with a weight pan by a cord passing over the pulley, _g_, which is so loaded that by the added velocity with which it strives to fall, the retardation already alluded to is overcome, so that the frame moves from left to right with even speed. in front of the frame, _a a_, is the tuning fork, _f_, which as estimated makes vibrations in a second. by the stylus, _y_, on the upper limb of the fork these oscillations are marked upon the sliding plate of glass as a wave line. lest, after the first impulses of the fork have been registered, they should soon die away, in front of it is an electro-magnet, h, whose pole-faces near the arms of the tuning fork pass over them. the latter, to be more strongly affected by the magnet, are provided with faces of soft iron. to the lower face of the lower arm of the fork a small sharp stylus is fastened, which, with each beat of the fork, comes into contact with the mercury in the little cup, _n_, or a spring used instead of it. this closes an electric circuit, which passes around the magnet, thence going through the tuning fork by the binding screw, _k_, and thence by connections not shown in the cut back to the battery. in consequence of the magnetism thus excited, the arms of the tuning fork are attracted by the poles of the magnet, and forced to beat with increased amplitude. in a short time a constant amplitude of oscillation is reached, when the magnetic impulses are of equal influence with the atmospheric resistance and the internal force of the tuning fork restraining its movements. finally, the stylus, _s_, which touches the glass plate directly above _y_, is for registering the moments when by the falling ball the sound is produced and when the observer presses the key. this is brought about by the rod, _i_, to which _s_ is firmly screwed, being jerked upward a short distance at each of these instants, so that the horizontal lines which the stylus, _s_, marks upon the screen passing in front of it are broken at both places. the mechanism which jerks the rod, _i_, upward is thus arranged: the inclined plate, _p_, on which the ball drops, is carried by the upper horizontal arm of an angular lever turning on the axis, _x_, and counterpoised by the balancing weight, _x'_. by the falling ball this arm is pressed downward, and the lower horizontal arm, _w_, of the lever is also moved. on a second horizontal axis the lever, _v_, partly concealed, moves, restricted as to its length of swing by the screws, _n_. as long as the concealed arm is not moved, _v_ is lightly pressed by the small spring, _e_, against _w_. the projection, _z_, at the upper end of _v_ holds the rod, _i_, which the strong spring, _h_, is continually pressing upward. when the ball falls upon the plate, _p_, the arm, _w_, presses against the lower end of _v_, the projection, _z_, sets free the rod, and it springs upward. this movement is soon arrested, as the projection, _z'_, engages with a stud situated on the right side of the rod, _i_. this projection is situated on the vertical arm of an angular lever whose other arm is the key, _t_. when the observer presses the key, the rod, _i_, again is jerked upward by the spring, _h_. the screw, _o_, tapped into the rod, _i_, prevents the rod going higher than necessary, by striking a plate, which also serves as guide for _i_. to determine the interval between the falling of the ball and pressing of the key, one has finally to count the waves inscribed by the tuning fork, which come under the portion of the line inscribed by _s_, which is bounded by the two breaks produced by the successive movements of the rod. to make the glass plate carried by the frame available for more observations, which plate can be used as a photographic negative, the frame, t, is adjustable up and down upon the pillars, n. this frame carries the tuning fork, mercury cup, _n_, and the electro-magnet, m. the spring, _s_, can also be moved up and down along the rod, i.--_h. heele in zeitschrift fur instrumentenkunde._ * * * * * a new disinfector. the accompanying engravings represent a new disinfecting apparatus invented by mr. w.e. thursfield, m. inst. c.e., of victorgasse, vienna. the principle on which its action is based is that the complete destruction of all germs in wearing apparel and bedding, without any material injury whatever to the latter, is only to be obtained by subjecting the articles infected, for a period proportionate to their structural resistance, to a moist heat of at least deg. fah. recent experiences in berlin have shown that, for security's sake, a temperature of deg. is better. to insure the thorough penetration of this temperature in every fiber, a heat of from deg. to deg. must be maintained in the disinfecting chamber itself. to obtain this by means of ordinary or superheated steam involves the employment of boilers working under a pressure of ½ to atmospheres, of disinfecting chambers capable of resisting an equal tension, and of skilled labor in attending to the same; in other words, a large initial outlay and correspondingly heavy working expenses in fuel and wages. [illustration: fig. i and ii the aero-steam disinfector.] the disinfecting apparatus, illustrated in a portable and stationary form, of the dimensions adopted by the sanitary authorities of vienna, budapest, prague, lemberg, teplitz, etc., and by the imperial and royal theresianum institute, and sanctioned for use in barracks, military hospitals, etc., by the austrian ministry of war, and for ambulance hospitals by the red cross, acts by means of a mixture of steam and hot air in such proportion that the steam, after expending its mechanical energy in inducting the hot air into the disinfecting chamber, is, by contact with the clothes or bedding of a lower temperature, not only condensed, but by condensation completely neutralizes the risk of injury through any chance excess of hot air. the boiler being practically open is inexplosive, and requires neither safety valves nor skilled attendance. the heat generated in the furnace is utilized to the utmost, and the escaping vapors form a steam jacket in the double casing of the disinfecting chamber. the method of manipulation reduces the danger of contagion to a minimum, as the clothes or bedding are placed in specially constructed sacks in the sick chamber itself, and, after being tightly closed, the sacks are removed and hung in the disinfector. the stationary apparatus, which is constructed to disinfect four complete suits of clothes, including underlinen, or one complete set of bedding, including mattress, is specially adapted for hospitals, barracks, jails, etc. its dimensions can easily be increased, but the size shown has proved itself, from an economical point of view, the best, as, where the quantity of articles to be disinfected varies, several apparatus can be erected at a less cost than one large one, and one or more be heated as the quantity of infected articles be small or large. in the accompanying drawing a is the boiler, which is filled by pouring water into the reservoir, b, until the same, entering the boiler at its lowest part through the tube, c, rises to the desired height in the water gauge, g. c acts also in the place of a safety valve. d is the fire space, e a movable grate, and f the coal hopper. the fuel consists of charcoal or coke. the boiler is emptied by the cock, h. i is a steam pipe connecting the steam space with the hot air tube, l¹. k is an auxiliary pipe to admit the steam into the chimney during stoppage for emptying and recharging the disinfecting chamber in continuous working. the admission of air is regulated by the handle, l, and the draught in the chimney, m, by the handle, n. o is the disinfecting chamber inclosed by the space, p, which acts at the same time as a steam jacket and as a channel for the downward passage of the vapors escaping from the chamber through the outlets, s. the lower portion of the disinfecting chamber, q, is funnel-shaped for the better mixture and distribution of the steam and hot air, and to collect any condensation water. q¹ is a sieve to catch any fallen article. the vertical tubes, s, which serve at the same time to strengthen the chamber, connect the lower portion of the steam jacket, p, with the circular channel, t, which is again connected with the chimney, m, by the tube, t'. the disinfection chamber is hermetically closed by the double cover, r, to the lower plate of which hooks for hanging the sacks are fastened. the cover fits in a sand bath, and is raised and lowered by means of the pulley chain, w, and the swinging crane, x. u is a thermometer indicating the temperature of the steam and hot air in the disinfecting chamber, v a cock for drawing off any condensation water, y a battery connected with an electrical thermometer to be placed in the clothes or bedding, and z the sacks in which the infected articles are hung. the portable apparatus, as shown, for heating with gas, or even spirits of wine, can also be heated with a similar steam and hot air apparatus as the stationary disinfector. in country towns or villages, or even in cities, whose architectural arrangements permit, the portable disinfector can easily be drawn by one man into the courtyard or garden of any house, and the process of disinfection conducted on the spot. its usefulness in campaigns for ambulance hospitals is self-evident. the letters denoting the several parts are the same as in the stationary apparatus. the portable disinfector is constructed to disinfect two complete suits of clothes or one mattress. the extremely favorable results are shown in the accompanying table of trials.--_the engineer._ table of results with wm. e. thursfield's steam and hot air disinfectors. part . portable apparatus. __________________________________________________________________________________ | | | | | | | | series of trials. | i. |ii. |iii.| iv.| v. | vi. | vii.|viii. ----------------------------------------+----+----+----+----+----+-----+-----+---- contents of boiler, in gallons | . | . | - | . | . | . | . | . water added during the process | - | . | - | - | - | - | . | . temperature of water degs. fah. | - | - | - | | | | | firing commenced with spirits of | | | | | | | | wine at hours min.| - | . | . | . | - | . | - | - firing commenced with gas at " | . | - | - | - | . | - | - | - firing commenced with coke at " | - | - | - | - | - | - | - | . firing commenced with charcoal at " | - | - | - | - | - | - | . | steam generated at " | - | . | . | . | . | . | . | . deg. in chamber registered by | | | | | | | | external thermometer at " | . | . | . | - | - | - | . | . deg. in clothes registered by | | | | | | | | electrical thermometer at " | - | - | - | . | . | . | - | - deg. in clothes registered by | | | | | | | | electrical thermometer at " | - | - | - | - | - | - | . | . highest temperature in chamber | | | | | | | | registered by external thermometer deg.| - | | | - | | | | mean temperature in chamber | | | | | | | | registered by external thermometer " | | | | | - | | | trial closed at hours, min. | . | . | . | . | . | . | . | . max. therm. registered in mattress deg.| | - | - | - | - | - | - | - max. therm. registered in overcoat "| - | | | - | - | - | | max. therm. registered in winter coat "| - | - | - | | | | - | - max. therm. regis'd in winter trousers "| - | | | - | - | - | - | - max. therm. regis'd in summer trousers "| - | | | - | - | - | - | - time required to generate steam min. | - | | | | | | | time required to generate deg. | | | | | | | | in chamber " | | | | - | - | - | | time required to generate deg. | | | | | | | | in clothes " | - | - | - | | | | - | - time required to generate deg. | | | | | | | | in clothes " | - | - | - | - | - | - | | total duration of process " | | | | | | | | water evaporated, in gallons | - | - | - | . | . | . | . | . consumption of spirits of wine pints | - | - | - | . | - | . | - | - consumption of gas, in cubic feet | - | - | - | - | | - | - | - consumption of cokes, in cbs | - | - | - | - | - | - | - | consumption of charcoal, in cbs | - | - | - | - | - | - | . | - ----------------------------------------+----+----+----+----+----+-----+-----+---- part . stationary apparatus. __________________________________________________________________________________ | | | | | | | series of trials. | ix. | x. | xi. | xii.|xiii.| xiv.| xv. ----------------------------------------+-----+-----+-----+-----+-----+-----+----- contents of boiler, in gallons | . | . | . | . | . | . | . water added during the process | . | - | - | . | . | - | - temperature of water degs. fah. | | | | | | | firing commenced with spirits of | | | | | | | wine at hours min. | - | - | - | - | - | - | - firing commenced with gas at " | - | - | - | - | - | - | - firing commenced with coke at " | - | . | . | . | . | - | - firing commenced with charcoal at " | . | - | - | - | - | . | . steam generated at " | . | . | . | . | . | . | . deg. in chamber registered by | | | | | | | external thermometer at " | . | . | . | . | . | . | . deg. in clothes registered by | | | | | | | electrical thermometer at " | - | - | . | - | - | - | - deg. in clothes registered by | | | | | | | electrical thermometer at " | - | - | - | . | . | . | . highest temperature in chamber | | | | | | | registered by external thermometer deg.| | | | | | | mean temperature in chamber | | | | | | | registered by external thermometer " | | | | | | | trial closed at hours, min | . | . | . | . | . | . | . max. therm. registered in mattress deg.| - | - | - | - | - | - | - max. therm. registered in overcoat "| | | | - | - | - | max. therm. registered in winter coat "| - | - | - | | | | - max. therm. regis'd in winter trousers "| | - | | - | - | - | - max. therm. regis'd in summer trousers | | - | | - | - | - | - time required to generate steam min | | | | | | | time required to generate deg. | | | | | | | in chamber " | | | | | | | time required to generate deg. | | | | | | | in clothes " | - | - | | - | - | - | - time required to generate deg. | | | | | | | in clothes " | - | - | - | | | | total duration of process " | | | | | | | water evaporated, in gallons | . | - | - | . | - | . | . consumption of spirits of wine pints | - | - | - | - | - | - | - consumption of gas, in cubic feet | - | - | - | - | - | - | - consumption of cokes, in cbs | - | - | . | . | - | - | - consumption of charcoal, in cbs | - | - | - | - | - | . | . ----------------------------------------+-----+-----+-----+-----+-----+-----+----- n.b.--in every case, even in the trials v. and x., in which the temperature in the disinfecting chamber rose above deg. fah., the clothes, owing to the complete saturation of the hot air with live steam, remained absolutely unimpaired. the column "water evaporated" shows the quantity of live steam passing through the disinfecting chamber averages cubic feet per minute with gas or spirits, and cubic feet with charcoal or coke in the portable and cubic feet in the stationary apparatus. trials vi., vii., and viii. took place in open air. according to trial xii., from to complete suits of clothes can be disinfected at an expenditure of about cbs. of coke per diem. * * * * * drawing instrument for accurate work. by j. lehrke. this arrangement consists in a cylindrical metal or horn mounted lens two to four centimeters long, and magnifying two or three times, and two or three centimeters in diameter, whose side is provided with a contrivance for holding after it has been pushed into place a copying needle, a protractor, etc. while hitherto the architect in using millimeter paper must hold separately in his hands a magnifying glass and needle, while the engraver holds the engraving tool inclined in one hand and the magnifying glass in the other, or must work under a large lens standing on three feet, it is now possible by a firm connection between the lens and needle or other instrument to draw directly with one hand and under the lens. in the accompanying cut one of these lenses is shown in section, a, in which the glass is set obliquely, in whose focus the needle, _a_, is held and the field of view is enlarged. a longer description is unnecessary, as the illustration gives the best explanation. it need only be remarked that the stud, _s_, projecting a little near the glass, is for the purpose of preventing the instrument from leaving the position coinciding with the plane of the drawing. for architects and engineers is provided a small compass, _b_, of about cm. diameter, for laying off parallel widths, for making smaller scales and the like. in these cases it is substituted for the needle. in like manner for calculating cross profiles by graphical methods, for reading parallel divisions, for estimating areas, or revising maps, a finely divided prismatic ivory rule, _c_, can be placed under the glass, b, and will do good service. in this case the plane of the lens must be perpendicular to the axis of the tube. [illustration: improved drawing instrument.] for draughtsmen a parallel drawing pen, something like _b_, is used, which gives several lines at once, perfectly parallel and close together; or a drawing pen with which the smallest signatures, such as boundary stones and figures, can be made neatly and exactly, which is secured like the needle, _a_, and for which the cylinder serves also as pen holder, offers a great advance. thus a whole series of instruments can be used with the lens. for instance, a naturalist can use with it a knife or other instrument. to avoid injury from the instruments, one should, in laying down the cylinder, place it on its side. it is also recommended that on the outer tube of the frame, which is appropriately lacquered of black color, white arrows should be placed in the direction of the points of the instrument, so that the eyes shall be protected from injury in handling the instrument, as by the points being stuck into the pupil, owing to lifting the instrument in an inverted position.--_zeitschrift fur instrumentenkunde._ * * * * * barlow's machine for moulding candles. that style of machine for moulding candles in which the candles are forced out at the top by means of a piston is the one most employed, and it is an apparatus of this kind that we illustrate herewith. in its construction, this apparatus presents some important improvements in detail which it is of interest to set forth. the improvements made by the messrs. barlow have been studied with a view of manufacturing candles with conical ends, adapted to all chandeliers, without interfering with rapidity of production or increasing the net cost. these gentlemen have likewise so simplified the continuous system of drawing the wick along as to prevent any loss of cotton. in the next place, the structure of the moulds, properly so called, is new. instead of being cast, as is usually the case, they are rolled and drawn out, thus giving them smooth surfaces and permitting of their being soldered, are assembled by means of threaded bronze sockets. the engravings between figs. and show these two modes of fixation. at _a_ may be seen the old method of junction by soldering, and at _b_ the screwing of the moulds into the socket. this machine consists of a box which is alternately heated and cooled, and which is fixed upon a frame, a, at the lower part of which are located the wick bobbins, e. toward the top of the machine there is a mechanism for actuating the two pairs of jaws, b, which grasp the candles forced upward by the play of the pistons, d. this mechanism, which is controlled by a lever, acts by means of an eccentric. [illustration: figs. and . barlow's candle moulding machine.] the pistons, d, are hollow, and are provided above with pieces which form the small end of the candles. instead of using tin, as is usually done, the messrs. barlow employ galvanized iron in the construction of these pistons, and mount them through screw rings--no soldering being used. for this reason, any workman whatever can quickly replace one of the tubes. all the pistons are placed upon a horizontal table, which is made to rise and descend at will, in order to regulate the length of the candles and remove them from the mould. a winch transmits the motion which is communicated to it to two pairs of pinions that gear with racks fixed to the frame to lift the table that supports the pistons. how these latter are mounted may be seen from an inspection of figs. to . this new arrangement of spiral springs for the purpose is designed to hold the pistons on the table firmly, and at the same time to prevent the shock that their upper ends might undergo in case of an abrupt turn of the winch. moreover, the forged iron plate, h, is not exposed to breakage as it is in other machines, where it is of cast iron. the bobbins already mentioned revolve upon strong iron rods, and the moving forward of the wick in the moulds is effected automatically by the very fact of the manufactured candles' being forced out. these latter are held in position through the double play of the jaws, b, while the stearic acid is flowing into the upper part of the moulds. the cotton wick is thus drawn along and kept in the axis of the candles. [illustration: figs. , , . barlow's candle moulding machine.] one peculiarity of the machine consists in the waste system applied to the mould box. steam or hot or cold water is sent into the latter through the conduit, l, starting from a junction between pipes provided with cocks. when the water contained in the box is in excess, it flows out through the waste pipes, g, which terminate in a single conduit. owing to the branchings at t, and to the cocks of the conduits that converge at l, it is very easy to vary the temperature of the box at will. the warm or cold water or steam may be admitted or shut off simultaneously. when first beginning operations, the wick is introduced into each mould by hand. the piston table is raised by means of the winch, and is held in this position through the engaging of a click with a ratchet on the windlass. a fine iron rod long enough to reach beneath the pistons and catch the end of the wick is next introduced. after this is removed, the wick is fixed once for all, and in any way whatever, to the top of the mould. this operation having been accomplished, the piston table is lowered, and the machine is ready to receive the stearic acid. the moulds are of tin and are open at both ends. in order to facilitate the removal of the candles, they are made slightly conical. when the candles have hardened, the ends are equalized with a wooden or tin spatula, and then the piston table is raised. at this instant, the jaws, b, are closed so as to hold the candles in place. the latter, in rising, pull into the mould a new length of wick, well centered. a slight downward tension is exerted upon the wick by hand, then a new operation is begun. during this time, the candles held between the jaws having become hard, their wicks are now cut by means of the levers, c, and they are removed from the machine and submitted to a finishing process.--_revue industrielle._ * * * * * a new alkali process. in several former notes and articles in these pages, we have spoken of the severe crisis through which the old established, or "leblanc," process has now for some years been passing. it is, in fact, pushed well nigh out of the running by the newer process, known as the "ammonia-soda" process, and would have had to give up the battle before now were it not for the fact that one of its by-products, bleaching powder, cannot, so far, be produced at all by the ammonia-soda works. the bleaching powder trade has thus remained in the hands of the workers of the leblanc process, and its sale has enabled them to cover much of the loss which they are suffering on the manufacture of soda ash and caustic soda. in brief outline, the old leblanc process consists in the following operations: salt is decomposed and boiled down with sulphuric acid. sulphate of sodium is formed, and a large amount of hydrochloric acid is given off. this is condensed, and is utilized in the manufacture of the bleaching powder mentioned above. the sulphate of sodium, known as "salt cake," is mixed with certain proportions of small coal and limestone, and subjected to a further treatment in a furnace, by which a set of reactions take place, causing the conversion of the sulphate of sodium of the "salt cake" into carbonate of sodium, a quantity of sulphide of calcium being produced at the same time. the mass resulting from this process is known as "black ash." it is extracted with water, which dissolves out the carbonate of sodium, which is sold as such or worked into "caustic" soda, as may be required. the insoluble residue is the "alkali waste," which forms the vast piles, so hideous to look at and so dreadful to smell, which surround our large alkali works. the sulphuric acid required for the conversion of the salt into "salt cake" is made by the alkali manufacturer himself, this manufacture necessitating a large plant of "lead chambers" and accessories, and keeping up an immense trade in pyrites from spain and portugal. the development of the alkali trade in this country has been something colossal, and the interests involved in it and connected with it are so great that anything affecting it may safely be said to be of truly national importance, quite apart from what technical interest it may possess. the "ammonia-soda" process, which has played such havoc with the old style of manufacture, proceeds on totally different lines. briefly stated, it depends on the fact that if a solution of salt in water is mixed with bicarbonate of ammonium, under proper conditions, a reaction takes place by which the salt, or chloride of sodium, is converted at once into bicarbonate of sodium, the bicarbonate of ammonium being at the same time converted into chloride of ammonium. the bicarbonate of sodium settles out at once as insoluble crystals, easily removed, marketable at once as such, or easily converted into simple carbonate of sodium, and further into caustic soda, as in the ordinary "old" process. the residual chloride of ammonium is decomposed by distillation with lime, giving ammonia for reconversion into bicarbonate of ammonium, and chloride of calcium, which is a waste product. the maker of "ammonia" soda works direct on the brine, as pumped from the salt fields. his plant is simpler and less costly, and he arrives at his first marketable product much more rapidly and with very much lower working costs than the maker of leblanc soda, in spite of all the great mechanical improvements which have of late years been introduced into the old process, and which have cheapened its work. the original patents on the use of ammonium bicarbonate have, we understand, long since expired. but the working details of the process and much of the most successful apparatus have undergone great development and improvement during late years, all the important points being covered by patents still in force, and mainly, if not wholly, in the hands of the one large firm which is now carrying on the manufacture in this country, and is controlling the market. the one weak spot of the ammonia-soda process, as we mentioned before, is its inability to supply hydrochloric acid or chlorine, and so allow of making bleaching powder. time after time it has been announced positively that the problem was solved, that the ammonia-soda makers had devised a method of producing hydrochloric acid or chlorine, or both, without the use of sulphuric acid. but the announcements have so far proved baseless, and at present the leblanc makers are getting incredulous, and do not much excite themselves over new statements of the kind, though they know that if once their rivals had this weapon in their hands the battle would be over and the leblanc process doomed to rapid extinction. such is at present the state of the struggle in this great industry, and the above outline sketch of the two processes is designed to give some idea of the conditions to such of our readers as may not have any special knowledge of these manufactures. at the present moment great interest is being taken in a new process, about to be put to work on a large scale, which is designed to take up the cudgels against the ammonia process and enable the leblanc makers to continue the fight on something more like equal terms. we allude to the process proposed and patented by messrs. parnell & simpson, and about to be worked by the "lancashire alkali and sulphur company," at widnes. we recently had the opportunity of inspecting fully the plant erected, and of having the method of procedure explained to us. we look upon the new process as such a spirited attempt to turn the tide of a long and losing battle, and as so very interesting on its own merits, that an account of it in these pages will be thoroughly in place. the main idea of the process is to combine the "leblanc" and the "ammonia-soda" manufacture. but in place of using caustic lime to decompose the ammonium chloride and get back the ammonia, the "alkali waste" spoken of above is employed, it being found that not only is the ammonia driven off, but that also the sulphur in the "waste" is obtained in a form allowing of its easy utilization, it and the ammonia combining to form ammonium sulphide, which passes over in gaseous form from the decomposing apparatus. this ammonium sulphide is, as we shall see, quite as available for the working of the ammonia-soda manufacture as pure and simple ammonia, and all the sulphur can be obtained from it. in outline the process is as follows: we will suppose that a quantity of bicarbonate of sodium has been just precipitated from a brine solution, and we have the residual ammonium chloride to deal with. this is decomposed by "alkali waste," giving a final liquor of calcium chloride, which is run to waste, and a quantity of ammonium sulphide gas. this latter is led at once into a solution of salt in water, till saturation takes place. into this liquor of brine and ammonium sulphide _pure_ carbonic acid gas is now passed. the ammonium sulphide is decomposed, pure sulphureted hydrogen gas is given off, which is conducted to a gas holder and stored, while ammonium bicarbonate is formed in the liquor, which brings about the conversion of the salt into bicarbonate of sodium, ready for removal and preparation for the market. it will be observed that we printed the word _pure_ in italics in speaking of the carbonic acid used. this is one of the great points in the process, as in order that the sulphureted hydrogen gas obtained shall be concentrated and pure, only pure carbonic acid can be used in liberating it. the apparatus employed in its preparation is perhaps the most ingenious part of the works, and well worthy of attention by others besides alkali makers. the method is based on the fact that if dilute impure carbonic acid is passed into a solution of carbonate of sodium, the carbonic acid is absorbed, bicarbonate of sodium being formed, and the diluting gases passing away. the bicarbonate of sodium on heating gives up the extra carbonic acid, which can be collected and stored pure, while the liquor passes back to simple carbonate of sodium, to be used over again as an absorbent. this is not at all new in theory, of course, nor is this the first proposal to use it commercially; but it is claimed that this is the first successful working of it on a large scale. the gases from a large limekiln supply the dilute carbonic acid gas, which contains per cent. to per cent. of pure gas, the principal diluting gas being, of course, nitrogen. this kiln gas is drawn from the kiln by a blowing engine, and is first cooled in two large receivers. it is then forced into the solution of sodium carbonate in the absorption tower, ft. high by ft. diameter, filled with the liquor. the tower has many diaphragms and perforated "mushrooms," to cause a proper dispersion of the gases as they ascend through the liquor. the strength of liquor found best adapted for the work is equal to a density of about ° twaddell. after saturation the mud of bicarbonate of sodium is drawn off and passed into the "decomposer," a tower ft. high by ft. in. in diameter, with perforated shelves, into which steam is blown from below, the liquor passing downward. the bicarbonate is decomposed, pure carbonic acid being given off. this is passed through a scrubber and into a gas holder ready for use. the liquor, which has now returned to the state of simple carbonate of sodium, only requires cooling to be ready to absorb a fresh lot of carbonic acid gas. the cooling is effected in a tower packed loosely with bricks, the hot liquor trickling down against a powerful current of air blown in from below. liquor has been cooled in this way, in once passing through the tower, from ° fahr. to ° fahr., but of course the exact cooling obtained depends more or less on the temperature of the atmosphere. the next stage of the process, if we follow on after the preparation of the pure carbonic acid, is the employment of the gas for the decomposition of the ammonium sulphide absorbed in a brine liquor as above explained. the brine and ammonium sulphide are contained in what is known as a "solvay tower," provided with proper means for dispersion and absorption of the carbonic acid gas. the precipitated bicarbonate of sodium is removed and washed, and prepared for the market in whatever form is required, the sulphureted hydrogen gas being led to a holder and stored, as before stated. the decomposition of the ammonium chloride by means of "alkali waste" is carried out in a specially designed still. this is a tower ft. high by ft. diameter, divided by horizontal plates into compartments of about ft. in. in height. these compartments communicate with one another by means of pockets, or recesses, in the shell of the tower. a vertical shaft, with arms, revolves in the tower. the "waste" is fed in at the top by means of hopper and screw feed. the liquor is heated by steam blown in to over ° fahr. the ammonium sulphide is led direct into an absorbing vessel full of brine. it now only remains to see how it is proposed to deal with the sulphureted hydrogen gas which represents the sulphur recovered from the waste. it can be burnt direct to sulphurous acid and utilized for the production of vitriol perfectly pure and free from arsenic, commanding a special price. but messrs. parnell & simpson state that by a method of restricted combustion they are able to obtain nearly all the sulphur as such, and put it on the market on equal terms with the best sicilian sulphur. we did not gather that this has yet been done on the working scale, however. it will be seen that it is proposed that a leblanc alkali maker shall continue to produce a portion of his make by the old process, but shall erect plant to enable him to make another portion by the parnell & simpson method, using his leblanc "waste" in place of the caustic lime now employed by the ammonia soda people. he is thus to have the benefit of the cheaper process for, say, half his make, while he further cheapens the ammonia method by saving the cost of lime and by recovering the sulphur otherwise lost in his waste. the saving in lime is stated to be one ton for each ton of sodium carbonate produced, or in cash value about s. per ton at widnes, while the sulphur saved is estimated to be cwt. per ton of sodium carbonate. we reproduce these figures with all reserve, not being ourselves sufficiently specialists to judge of them. but we were assured that they represent the minimum expected, and reasons were given to us to show that they would probably be exceeded. another gain for the leblanc maker would be that he will escape the cost of removal and disposal of a portion of his refuse or waste. the plant now erected was calculated for a yield of one hundred tons carbonate of sodium and about thirty-five tons of sulphur per week, but it now appears likely that this will be exceeded; while the carbonic acid plant was supposed to be equal to a yield of tons of pure gas per day, and is now found capable of doing twice as much. a few weeks will now bring this new combination process into the active and crucial test of the markets. chemists and chemical engineers have all along taken a keen interest in the ingenious ideas of parnell & simpson. commercial men are no less interested in the financial result of the experiment about to be tried at the expense of a few gentlemen of liverpool and district. so far as we can learn, opinions are to some extent divided, though many good judges are very hopefully inclined. for our own part, speaking with diffidence, as being a little off our regular track of work, we will only say that we were favorably impressed with what we saw and heard; and we certainly wish the venture that full success which its cleverness and its pluck, as well as its great importance at this crisis, deserve for it.--_engineering_. * * * * * temperature of gas distillation. an important subject for investigation, which has not yet been satisfactorily determined, is the temperature at which it is most beneficial to distill coals of various qualities. the practice of allowing the charge to remain in the retort for some time after most of the gas has been driven off, to enable (it is said) the retort to recover heat for the next charge, often leads to misconception as to the true temperature of carbonization. the effect of this is to equalize the temperatures inside and outside the retort. this inside temperature is not maintained, the temperature outside not being high enough to transmit the heat with sufficient rapidity; and so, in an apparently hot retort, the coal may be carbonized at a comparatively low temperature. a truer test of temperature is that of the outside of the retort, which should be not less than ° to ° fahr. above the temperature necessary for proper carbonization. in all experiments relating to temperature pretending to any degree of accuracy, a pyrometer of some kind should be used. judging of the temperature by the color is often misleading. not only may the eye be deceived, but different clays do not present the same appearance at the same temperature. a good, reliable pyrometer to estimate temperatures to (say) ° fahr. is much wanted. experience during the last few years with the high temperatures obtained by the use of regenerative furnaces has led me to the conclusion that higher heats than are usual may be employed with advantage, as regards both the quantity and the quality of gas, provided the retorts are heated uniformly throughout their length, and the weight and duration of the charge are so adjusted that the coal does not remain longer in the retort than is just sufficient to drive off the gas; and that the more rapidly the coal is carbonized, the better are the results. in two retorts of the same size, one making , and the other , cubic feet per day, the gas will be twice as long in contact with the surface of the retort in the former as in the latter--to the probable detriment of its quality, and increased tendency to stoppage in the ascension pipes. a subject closely allied to that just alluded to is the temperature of the gas as it leaves the retort. until within the last few years, it was generally assumed that this was not higher than from ° to ° fahr.; and a very plausible theory was given to account for such a comparatively low temperature. a discussion which took place a few years ago in the _journal of gas lighting_ showed that at that time opinions on this subject were not unanimous. but the conclusion arrived at seemed to be that the gas was not higher in temperature than that before stated; and if higher temperatures were observed, they were due to the tarry matter in the gas, and were not those of the gas itself. a little reflection is sufficient to show that the existence of gas intimately mixed with tarry matter at a high temperature, without being itself raised to that temperature, is a physical impossibility. in a paper read to a continental gas association about a year ago, the writer stated, as the result of many experiments, that unless the temperature in the ascension pipe rises above ° fahr., thickening of the tar in the hydraulic main and choking of the ascension pipe will certainly occur. this led me to make a series of experiments, extending over many months, on the temperature of the gas in the ascension pipes at different points and at various times during the charge. the results of these experiments may be of some interest, and may lead to further investigation. the temperatures were taken by mercurial thermometers registering ° fahr., except those near the mouthpiece, which were taken by a siemens water pyrometer. every care was exercised to insure accuracy; and the instruments were carefully adjusted. at a distance of inches from the mouthpiece, the temperatures varied from an average of °, shortly after the retort was charged, to ° at the end of the charge; at feet distant from the mouthpiece, the corresponding temperature was °, falling to ° at the end of the charge; and at feet, the average temperature varied from ° at the commencement to ° at the end of the charge. these are the averages of a number of experiments. in some instances they were considerably above these averages--temperatures over ° being frequently obtained. this is about the temperature of a low red heat, and is much higher than any i have seen recorded. when the gas was allowed to issue from a hole in the ascension pipe, ¼ inches in diameter, inches above the mouthpiece, a strip of lead held about an inch from the orifice was freely melted. in the settings on which these experiments were made, the middle ascension pipe takes the gas from the two central retorts; and it is of interest to note that in this pipe the temperature of the gas inches from the upper retort was found to be ° fahr., and at the point where it entered the hydraulic main it was ° fahr. zinc was freely melted by the gas issuing from a hole inches from the mouthpiece. the temperatures always fall toward the end of the charge; the fall of temperature in the ascension pipe being a good indication that the charge is worked off. they increase with the heat of the retort and with the weight of the charge. experiments were also made to ascertain the temperature of the gas in the retort; and for this purpose one of murrie's pyrometers was used, the action of which depends on the pressure produced by the vaporization of mercury in a malleable iron tube. the end of this tube was first rested on the top of the coal, but not in contact with the retort. it reached about inches into the retort, and therefore was not in the hottest part. in this position the temperature indicated shortly after charging the retort was ° fahr., gradually rising to ° fahr. the end of the tube was then embedded in the coal, when the pyrometer indicated a temperature of ° fahr. within minutes after the retort was charged; gradually rising toward the end of the charge as before. at the time these temperatures were taken, the retorts were each producing , cubic feet of gas per day. i had no opportunity of testing the accuracy of the statement that, with lower temperatures, there is a tendency to stoppage of the ascension pipes; but with these high temperatures (contrary to what might be expected) there is no trouble from stoppages. these experiments, so far as they have gone, lead to the conclusion that the temperature of the gas as it is evolved from the coal is not less than ° fahr., and that cooling commences immediately on the gas leaving the retort. the temperatures being far above that of liquefaction, the gases are cooled very rapidly. the temperature of the gas in the ascension pipe depends on the rapidity with which the gas is evolved--that is to say, the greater the quantity produced in a given time, the less effective is the cooling action of the mouthpiece and the ascension pipe; and although i had no opportunity of testing it, i should expect to find that with retorts making from , to , cubic feet of gas per day, the maximum temperature in the ascension pipe inches from the mouthpiece will not exceed ° to ° fahr., while with lower heats and lighter charges the temperatures will be still lower. that these temperatures have some effect in causing or preventing stoppage in the ascension pipes there can be no doubt; and it is important that this subject should be thoroughly investigated. it is of interest to consider what must be the physical condition of the gas at these high temperatures. all the hydrocarbons which are afterward condensed must then be in the condition of gases having various degrees of condensability, mixed with and rendered visible by a cloud of carbon particles or soot. if this soot could be removed from the gas at this stage without reducing the temperature, we should probably have no thick tar or pitch, but only comparatively light-colored oils; and it might possibly lead to an entirely different mode of conducting the process of condensation. these are a few of the subjects on which it is extremely desirable that we should possess that complete information which can only be obtained by well-directed investigations with different materials and under varying conditions. there are many others in connection with carbonization and purification which might be mentioned; but i think i have said sufficient to show the necessity that exists for more minute investigation and research. investigations such as are here indicated do not involve any large expenditure of money; but they do require care and intelligence to prevent errors being made. experiments should not be condemned as defective because the results differ from old-established theories; yet when this does happen, it is in all cases better to suspect the new experiment rather than the old theory, until the results have been fully established.--_wm. foulis, journal of gas lighting._ * * * * * the largest black ash furnace in the world. the widnes alkali company have recently erected an enormous revolving black ash furnace, which is ft. in length and has a diameter of ft. in. the inside length is ft. in., with a diameter of ft. in. the furnace is lined with , fire bricks and fire-clay breakers, each weighing ¼ cwt. the weight of salt cake per charge, i.e., contained in each charge of salt cake, limestone, mud, and slack, is tons cwt. for tons of salt cake charged there are also used about tons of lime mud and limestone and tons of mixing slack. the total amount of salt cake decomposed weekly is about tons, which may be calculated to yield tons of per cent caustic soda. there is claimed for this massive furnace an economy in iron plate, in expense on the engine power and on fuel consumed, as well as on wear and tear.--_watson smith, in industries._ * * * * * the statue of philip lebon. the inauguration of the statue of philip lebon, the inventor of lighting by gas, occurred on the th of june, at chaumont, under the auspices of the technical gas society of france. the statue, which we illustrate herewith, is due to the practiced chisel of the young sculptor antide pechine, who has perfectly understood his work, and has represented the inventor at the moment at which he observes a flame start from a glass balloon in which he had heated some sawdust. the attitude is graceful and the expression of the face is meditative and intelligent. the statue, which is ten feet in height, was exhibited at the last _salon_. it was cast at the barbedienne works. it would be impossible to applaud too much the homage that has just been rendered to the inventor of gas lighting, for philip lebon, like so many other benefactors of humanity, has not by far the celebrity that ought to belong to him. when we study the documents that relate to his existence, when we follow the flashes of genius that darted through his brain, when we see the obstacles that he had to conquer, and when we thoroughly examine his great character and the lofty sentiments that animated him, we are seized with admiration for the humble worker who endowed his country with so great a benefit. lebon was born at brachay on the th of may, . at the age of twenty, he was admitted to the school of bridges and roads, where he soon distinguished himself by his ingenious and investigating turn of mind. his first labors were in connection with the steam engine, then in its infancy, and on april , , the young engineer obtained a national award of $ to continue the experiments that he had begun on the improvement of this apparatus. it was at about the same epoch that lebon was put upon the track of lighting by gas, during a sojourn at brachay. he one day threw a handful of sawdust into a glass vial that he heated over a fire. he observed issuing from the bottle a dense smoke which suddenly caught fire and produced a beautiful luminous flame. the inventor understood the importance of the experiment that he had just performed, and resolved to work it further. he had just found that wood and other combustibles were, under the action of heat, capable of disengaging a gas fit for lighting and heating. he had seen that the gas which is disengaged from wood is accompanied with blackish vapors of an acrid and empyreumatic odor. in order that it might serve for the production of light, it was necessary to free it from these foreign products. lebon passed the vapor through a tube into a flask of water, which condensed the tarry and acid substances, and the gas escaped in a state of purity. this modest apparatus was the first image of the gas works; and it comprised the three essential parts thereof--the generating apparatus, the purifying apparatus, and the receiver for collecting the gas. one year afterward, the inventor had seen fourcroy, prony, and the great scientists of his epoch. on the th of september, , he took out a patent in which he gives a complete description of his thermo lamp, by means of which he produced a luminous gas, while at the same time manufacturing wood tar and pyroligneous or acetic acid. in this patent he mentions coal as proper to replace wood, and he explains his system with a visible emotion and singular ardor. in reading what he has written we are struck with that form of persuasion that does not permit of doubting that he foresaw the future in reserve for his system. unfortunately, lebon could not devote all his time to his discovery. being a government engineer, without money and fortune, he had to attend to his duties. he went as an ordinary engineer to angouleme, but he did not forget his illuminating gas, and he strongly regretted paris, which he termed "an incomparable focus of study." he devoted himself to mathematics and science, he made himself beloved by all, and his mind wandered far from his daily occupation. the engineer in chief soon complained of him, but a committee appointed to investigate the charges that had been made against him affirmed that he was free from any reproach. he was sent back to his post, but war was decimating the resources of france, and the republic, while bonaparte was in italy, no longer had any time to pay its engineers. lebon wrote some pressing letters to the minister, asking for the sums due on his work, but all of them remained without reply. his wife went to paris, but her applications were fruitless. she wrote herself to the minister the following letter, which exists in the archives of the school of bridges and roads: "liberty, equality, fraternity--paris. messidor, year vii. of the french republic, one and indivisible--the wife of citizen lebon to citizen minister of the interior: "it is neither alms nor a favor that i ask of you, it is justice. i have for two months been languishing at leagues from my household. do not, by further delay, force the father of a family, for want of means, to leave a state for which he has sacrificed everything. ... have regard for our position, citizen. it is oppressive, and my demand is just. there is more than one motive to persuade me that my application will not be fruitless with a minister who makes it a law and duty for himself to be just. "greeting and esteem. your devoted fellow-citizen, "madame lebon, _nee_ de brambille." in , lebon was called to paris, as _attache_ in the service of blin, engineer in chief of pavements. he took a second patent--a true scientific memoir full of facts and ideas. it speaks of the numerous applications of illuminating gas and its mode of production, lays down the basis of the entire manufacture--furnaces, condensers, purifiers, gas burners. nothing is forgotten, not even the steam engine and balloon. lebon proposed to the government to construct an apparatus for heating and lighting the public buildings, but the offer was rejected. it was then that the unfortunate inventor, wearied by all his tentatives, fatigued by his thousands of vexations, made up his mind to have recourse to the public in order to convince it of the utility of his invention. he rented the hotel seignelay, st. dominique-st. germain st., and invited the public thither. here he arranged a gas apparatus, which distributed light and heat to all the rooms. he lighted the gardens with thousands of gas jets in the form of rosettes and flowers. a fountain was illuminated with the new gas, and the water that flowed from it seemed to be luminous. the crowd hastened from all parts and came to salute the new invention. lebon, excited by this success, published a prospectus, a sort of profession of faith, a model of grandeur and sincerity, a true monument of astonishing foresight. he followed his gas into the future and saw it circulating through pipes, whence it threw light into all the streets of future capitals. we reproduce a few passages from this remarkable production: "it is painful," says he, "and i experience the fact at this moment, to have extraordinary effects to announce. those who have not seen cry out against the possibility, and those who have seen often judge of the facility of a discovery by what they have to conceive of its demonstration. if the difficulty is conquered, the merit of the inventor vanishes with it. i would rather destroy every idea of merit than allow the slightest appearance of mystery or charlatanism to exist. "this aeriform principle is freed from those humid vapors that are so injurious and disagreeable to the organs of sight and smell, and of the soot which soils apartments. purified to perfect transparency, it travels in the state of cold air, and is led by the smallest as well as frailest pipes, by conduits an inch square, formed in the plaster of ceilings or walls, and even tubes of gummed taffety would perfectly answer the purpose. only the extremity of the tube, which puts the inflammable gas in contact with the air, and upon which the flame rests, should be of metal." [illustration: statue of philip lebon.] every one finally paid homage to the illustrious inventor, and a committee appointed in the name of the minister affirmed that "the advantageous results given by the experiments of citizen lebon have met and even exceeded the hopes of the friends of the sciences and arts." napoleon i. soon granted lebon a concession in the forest of rouvray for the organization of an industry of wood distillation and gas making. unfortunately, lebon was obliged to undertake too many things at once. he prepared the gas, and produced acetic acid and tar that he had to send to harve for the use of the navy. despite all his trouble and fatigue, he had something like a ray of hope. he believed that he saw the day of fortune dawning. his works were visited by numerous scientists, and among others the russian princes galitzin and dolgorouki, who, in the name of their government, proposed to the inventor to transfer his plant to russia, he to be free to set forth the conditions. lebon refused this splendid offer, and, in an outburst of patriotism, answered that his discovery belonged to his country, and that no other nation should before his own have the benefit of his labors. the hopes of lebon were of short duration. enemies and competitors caused him a thousand troubles, and the elements themselves seemed to turn against him. during a hurricane, the humble house in which he dwelt was destroyed, and a fire shortly afterward consumed a portion of his works. fatality, like the genius of old, seemed to be following up the unfortunate inventor; but sorrows and reverses could not have any hold on this invincible spirit, who was so well seconded by a wife of lofty character. lebon, always at work, was seemingly about to triumph over all obstacles, and the hour of the realization of his project of lighting on a large scale was near, when a death as tragic as it was mysterious snatched him from his labors. on the very day of the crowning of the emperor, december , , the body of philip lebon was found lying inert and lifeless in the champs elysees, exhibiting thirteen deep wounds made by a dagger.--_la nature._ * * * * * a new process for the distillation and concentration of chemical liquids. especially adapted to the manufacture of sulphate of ammonia. inventor, alex. angus croll.[ ]. [footnote : read at the recent meeting of the gas institute, glasgow.] by george anderson, of london. the paper i have to lay before you describes the last product of the brain of one of your past presidents--alexander angus croll--in connection with our industry. it may not be so well known to some of the younger as it is to many of the older members of the institute that the fertile brain of mr. croll has done much for the improvement and the extension of the gas industry. i consider that he has been the most successful pioneer both in the cheapening and the purification of gas--two elements without which our industry would progress but slowly if at all; and the success which has crowned his efforts, to our advantage, has reflected itself favorably on himself, showing by his financial success that he has also been a good man of business. all these are conditions which enhance the value of this paper. in the present instance, i claim no other credit than that of being the mouthpiece of mr. croll, whose assistant i was for ten of the busiest and most important years of his eventful life; and having (with my son bruce) taken part in the experiments, i have been asked to describe the process to the institute. the manufacture of sulphate of ammonia, as hitherto conducted, has consisted either in bringing together sulphuric acid and ammoniacal liquor or in distilling the liquor by external heat, or by the introduction of steam, and bringing it into contact with the acid in the form of gases and vapor of water. in either case a large volume of noxious gases is given off, the chief of which, being sulphureted hydrogen, has to be fixed by another method, in order to comply with acts of parliament for the prevention of nuisances. by the processes hitherto used, we sometimes get only ¼ tons of salts to every ton of acid used; while in the more perfect forms of apparatus, we may get - / tons of salts. by mr. croll's process, however, we get an increased yield of salts on the acid used, as follows: the experiments were made with sulphuric acid of the specific gravity of , or nearly concentrated oil of vitriol; and the quantity used was ounces in each experiment. the ammoniacal liquor was of uniform strength throughout all the experiments, being kept in a corked jar; and the solution of sulphate of ammonia was passed through filter paper before being crystallized. thus we obtained a white salt. in each experiment the solution of sulphate was divided into four equal parts by weight, and one part filtered and crystallized to dryness over a spirit lamp; the weight in each experiment being as nearly as possible the same, or ¼ oz. of salt to oz. of acid--being in the proportion of oz. of sulphate to lb. of acid, or ½ cwt. of salts to cwt. of acid. the results surprised me; and being uniform over a number of experiments, pleased me. still, i preserved the character of a critic and said: "i should like to treat oz. of acid in the ordinary way--saturating it with ammoniacal liquor, and then crystallizing it." "oh!" mr. croll said, "we know what that will produce." i replied: "yes; but i would like to do it with the precise acid and liquor we have been using, so that we may have the experiment on all fours with yours, barring your process." these experiments were made at his country residence. i was staying there for the night. so next morning i got down before him, went at my experiment, saturated oz. of acid (and a nice smell i made) out in the grounds, treated it afterward by division into four parts, filtered and crystallized it, all as before, with the result that i obtained ¾ oz., as against his ½ oz.--or in the proportion of ½ cwt. of salt to the ton of acid, as against his ½ cwt. i now thought of business. "what is the royalty to be?" i said, as we sat at breakfast. this we settled as we scotch say "in a crack," or as an englishman would say "in a jiffy." mr. croll decided to have the apparatus put up on a manufacturing scale here in glasgow; and i determined to erect similar apparatus at one of my gas works. i dare say that it will be uppermost in your minds, whence comes the increased yield of salts? well, i will state one fact, and leave you to ruminate on it, namely, by mr. croll's process we did not seem to produce any sulphureted hydrogen. the experiments were conducted in a room with ordinary doors and windows, but without a chimney; and we were not troubled with any offensive smell--a state of things that could not possibly have existed had we been experimenting with any other apparatus hitherto employed in the manufacture of sulphate of ammonia. the apparatus, which will presently be described, only substitutes, for the present mode of distillation, a new one, which forms the subject of mr. croll's patent. all other parts of present apparatus can remain as they now exist. mr croll has also introduced another mode of producing sulphate of ammonia, which dispenses with all the apparatus hitherto in use after the distillatory portion, and produces the salt in a state fit for the farmer, ready to be put on the land. this process consists in sending the products of distillation through a vessel filled with wood sawdust saturated with sulphuric acid. the ammonia becomes fixed and crystallized in the sawdust, and is ready for use. there are many works, both at home and abroad, to which the conveyance of sulphuric acid is both difficult and expensive, on account of the cost of carriage and the breakage which occurs; and thus in many such works the ammonia is not utilized. this saturated sawdust process will, i think, remove the difficulty; for i find that dry sawdust absorbs double its own weight of sulphuric acid, and this could be conveyed in the most ordinary casks in a damp state, and save all waste and annoyance from breakage of bottles. in this state it could be used by the farmer, or the sulphate of ammonia could be washed out, crystallized, and exported in the state of salt. in the remainder of this paper i have been assisted by my son bruce, who also assisted in the experiments that i have described. he has since been engaged on the trials on a manufacturing scale; and i ask you to permit him to read the concluding portion of the paper, in which he will describe the process, and what he has done. the process referred to in the foregoing portion of the paper is a method employed for heating the liquor, whereby a chemical action is brought into play, with the results already mentioned. this method consists in passing the products of combustion of a furnace from a clear fire in a hot state through a still containing the ammoniacal liquor. the hot gases from the furnace impart their heat to the liquor, causing the volatilization of the condensed gases, and at the same time act chemically upon the liquor and evolved gases, so that ammonia and sulphuric acid are resulting products, in the compound state of sulphate of ammonia. the formation of the ammonia produced in the process is probably due to the decomposition of nitrogenous bodies contained in solution in the liquor--the sulphocyanide, for instance; the nitrogen being given off in the form of ammonia. of the sulphuric acid produced, we look upon the sulphureted hydrogen as the source, also any sulphites existing in the liquor, which in their volatile state take up the atom of oxygen necessary for their conversion into sulphate. [illustration] the apparatus used in working the process consists of a tower still, containing a number of superposed trays about or inches apart, with a lipped hole through the bottom of each at the side. the trays are so placed in the tower that the holes are at alternate sides. the liquor passes into the top of the still, and zigzags down through the series of trays, as in an ordinary coffey still. the bottom tray differs from the rest; being much deeper, and having holes through it connecting it with the furnace, which is set immediately below it. the products of combustion of the fuel are caused to pass from the furnace up through the holes in the trays in the still, and, together with the gases evolved from the liquor, are directed into the saturator, where the sulphate of ammonia is obtained either in solution or in the crystalline state. where the process is at present being worked, an exhauster is used to draw the furnace gases through the still; but it might be advantageous to use a blower. a small plant has been put in action at the gas works in kilkenny and another on a larger scale, and differing somewhat in detail, here in glasgow at the alum and ammonia company's works, where the liquor from the tradeston gas works is converted. the trials on a working scale have only been made at both places within the past ten days; and, so far, nothing has appeared against the principle, though in certain of the details of construction some alterations are being made to improve it. the extra yield of salt from a given quantity of acid obtained in the experiments has been proved in practice, as also the absorption of the sulphureted hydrogen. the other day, while ammoniacal liquor of about oz. strength was being run at the rate of gallons per hour through the still, feet in diameter and feet high, containing seventeen trays, no smell of sulphureted hydrogen was perceptible from the waste gases from the saturator, although on applying lead paper a slight trace of this impurity was noticeable, and it may be stated that the gases were being delivered at the ground level, where there was no difficulty in testing them. in the glasgow apparatus we have found it advisable to enlarge the pipe leading the gases into the saturator, as the volume of these is much greater than would be the case in the ordinary method of working. further experience will probably indicate the desirability of increasing the height of the still, which, being only feet, is not more than half the height that coffey stills are ordinarily made. * * * * * the analysis of urine. introduction. whatever may be the position of british pharmacists in comparison with those of other countries, it cannot be said that they have paid the attention to the analysis of urine which the subject has received from pharmacists on the continent. considering the importance of the subject, this curious neglect can only be attributed to the fact that the pharmacist in great britain is but slowly attaining the position of chemical expert to the physician, which his foreign _confrere_ has so long held with credit and even distinction. in france, for example, m. méhu, whose name is familiar to readers of this journal, is looked upon as one of the leading authorities on morbid urine and its analysis, and yet a list of goodly pharmaceutical papers shows that, as the medical analyst, he has not forgotten his connection with pure pharmacy. there are several points about urinary analysis which entitle it to a very high position in the estimation of pharmacists. in the first place, the physician is no more likely to be fonder of the test tube than of the pestle, of analyzing urine than of compounding his own medicines. leading men in the profession are more and more setting their faces against the dispensing doctor, and there are numbers among them who admit that they succeed no better as analysts than they do as dispensers. some old fashioned practitioners trouble themselves very little about their patients' urine, except, perhaps, in respect of sugar and albumen. on the other hand, numbers of leading physicians, including especially those highly educated gentlemen who cultivate a consulting practice, are in the habit of pushing urinary analysis almost to an excess. one well-known specialist of the writer's acquaintance, with an extensive west end practice, makes quantitative determinations of urea, uric acid, and total acidity, in addition to conducting other diagnostic experiments, on every occasion that he interviews his patients. by this means he has accumulated in his case books a mass of data which he considers most valuable as an aid to diagnosis, and through that to successful treatment. pharmacists are proverbially neat-handed, as mr. martindale would say, and their habit of conducting dispensing operations which involve the dexterous manipulation of very small quantities of material fit them admirably to undertake volumetric and other rapid analytical determinations. compared with the doctor there is no doubt that in this matter the chemist is _facile princeps_, and from the nature of their respective occupations such could only have been expected. a few chemists throughout the country lay themselves out to save their local doctors from unwelcome test tube practice, and these almost to a man find it pay. some charge a handsome fee to patients, and a small one when the analysis comes through the physician. others find it to their interest to furnish medical men with qualitative reports on sugar or albumen gratuitously. although this practice has certain obvious drawbacks, if a doctor sends his prescriptions to a chemist, the latter is often willing to gratuitously perform his chemical work. in the present article we propose to describe briefly but fully the methods which have been found of most value in practice. preliminary operations. it is the practice of some physicians to direct the patient to preserve all the urine passed in twenty-four hours, and to forward this in one bottle for analysis. others, again, merely send a small sample of "morning" and "evening" urine in separate phials, desiring only a comparative report. in the former case the _volume_ should be accurately measured, and the quantity noted either in fluid ounces or cubic centimeters before commencing the analysis. this need not be done if small samples only are received. the _color_ should be noted. it varies greatly, through every shade of yellow and amber to dark brown, with a tinge of green or red, if the coloring matter of bile or blood is present. also note relative _transparency_ or _cloudiness_, _specific gravity_, and _reaction_, as all these observations are useful in diagnosis. _odor_ is not quite so important. the _specific gravity_ should be taken at about ° f. in an ordinary specific gravity bottle, or more conveniently by means of a good _urinometer_. in the latter case it is very important to have an instrument of known accuracy, many of those in the market being valueless. urinometers of glass, though fragile, are decidedly more cleanly and less liable to get out of order than the gilded brass instruments carried in the pocket by many physicians. mr. j.j. hicks, of hatton garden, e.c., manufactures a very creditable "patent urinometer" at an extremely low cost. healthy urine has a density of from . to . ; but variations from this range are common. [illustration] a fair quantity of the urine, after shaking, should be placed in a tall conical glass vessel, to allow easy collection of the precipitate for subsequent, microscopical examination. if an abundant amorphous deposit of a fawn or pink--from _uroerythrin_--color slowly settles and is readily diffused, _urates_ in excess can be anticipated. their presence is proved by the readiness with which they dissolve on warming with the supernatant urine to about the temperature of the blood. no difficulty is experienced if small quantities of albumen are present, as that body is not coagulated until the temperature rises much higher. a sandy precipitate of free _uric acid_ will not dissolve on warming the urine, and its identity can further be determined by means of the microscope, or by applying a well-known color-reaction. a grain or so is oxidized into reddish alloxan and alloxantin by carefuly evaporating with a few drops of strong nitric acid on a piece of porcelain. a little ammonia is then added, when the fine _purple_ murexide stain will be produced. it is always advisable to mention the reaction to test papers of all samples received. urine is normally _acid_, but there are certain diseases which render fluid neutral or alkaline. the urea of acid urine on standing is changed by a putrefactive ferment into ammonic carbonate, but this decomposition in a state of health should not take place for at least twenty-four hours. alkalies, or organic salts of alkaline metals, when taken as medicine render the urine alkaline, and the indication is then not of much moment; but if none of these causes exist, the condition is of serious diagnostic import. where it is desired to determine the degree of acidity of the urine voided, say, by a gouty patient, a dilute volumetric solution of caustic soda should be employed, using a few drops of an alcoholic solution of phenolphthalein as an indicator, and reporting in terms of oxalic acid. the soda solution may conveniently contain the equivalent of one milligramme of recrystallized oxalic acid (h_{ }c_{ }o_{ }. h_{ }o) in each cubic centimeter. urea. carbamide, as it is called by systematic chemists, or _urea_, is next to water the largest constituent of urine, and forms about one-third of its total solids. derived from ammonic carbonate by abstracting two molecules of the elements of water, it is readily converted by putrefaction into that salt, and the urine under these circumstances becomes strongly alkaline in reaction. earthy phosphates then fall naturally out of solution, so that the putrid fluid is always well furnished with sediment. nitrogen that has served its purpose as muscle or other proteid leaves the animal economy chiefly in the form of urea, and its proportion in the urine, therefore, is a fair index of the activity of wasting influences. for its determination knop's sodic hypobromite method, on account of its convenience, is now generally preferred. the volumetric process of liebig, which depends on the formation of an insoluble compound of urea with mercuric nitrate, possesses no advantages and is troublesome to work. the principle of the hypobromite process is simple. in a strongly alkaline solution urea is broken up by sodic hypobromite, its nitrogen being evolved in the gaseous state, and its carbon and hydrogen oxidized to carbonic anhydride and water respectively. the volume of free nitrogen obtained bears a direct ratio to the amount of urea decomposed. [illustration] among the number of instruments which have been introduced for the purpose of conveniently measuring the evolved gas, that of gerrard, an illustration of which we give, is one of the simplest, cheapest, and best. the ureometer tube, _b_, is connected at the base with a movable reservoir, _c_, and by means of a rubber tube passing through a cork at the top to the generating bottle, _a_. to use the apparatus, fill _b_ to zero with water and have the reservoir placed so high that it contains only an inch or so of the liquid. replace the cork with attached tube tightly in _b_. now pour into the generating bottle c.c. of a solution prepared by dissolving part of caustic soda in ½ parts of distilled water, and dexterously break in the liquid a tube containing . c.c. of bromine. the tubes will be found very convenient, obviating entirely the suffocating fumes diffused in the act of measuring bromine. allow to stand in the solution of sodic hypobromite thus prepared a test tube containing exactly c.c. of the urine under examination. cork the bottle as shown in the illustration, see that the water is at zero, and that the liquid in the reservoir is at the same level, and then allow the urine to gradually mix with the hypobromite solution. cool the evolved gas by placing the bottle in cold water, adjust the levels of the water in the tube and reservoir (to obviate a correction for pressure), and read off the percentage of urea in terms of which the tube is graduated. stale urine, the urea of which has largely been converted into ammonic carbonate, still yields a very fair result, that salt being also completely split up by the powerful oxidant employed. should the urine contain albumen, it is advisable to remove it by boiling and filtering, as, although only slowly decomposed by the hypobromite solution, it communicates to the liquid such a tendency to froth that the disengagement of the nitrogen is seriously impeded. most of those alkaloids which might possibly be present do not yield the gas when treated in this manner, and therefore may be disregarded. sugar. glucose, so characteristic of _diabetes mellitus_, is not difficult of detection or estimation. the facility with which it reduces alkaline cupric, argentic, bismuthous, ferric, mercuric salts, indigo and potassic picrate and chromate solutions has been utilized for the preparation of several ready methods for its determination. trommer's test consists in adding enough cupric sulphate to color green, then excess of alkali, and boiling. yellow to brick-red cuprous oxide forms as a heavy precipitate if glucose is present. the organic matter of the urine prevents the precipitation of cupric hydrate on the addition of the alkali. this test is delicate and deservedly popular. fehling's well-known solution contains sodio-potassic tartrate, which serves the purpose chiefly of retaining the copper in solution. unfortunately, fehling's original solution has a tendency to become hyper-sensitive if kept long, a proneness to change that is much increased on dilution. when so altered, the solution will yield a more or less copious precipitate of cuprous oxide on merely boiling, and quite independent of the presence of glucose. this decomposition is obviated by preserving the copper salt in a separate solution from the tartrate and alkali, and mixing before use. schmiedeberg substitutes mannite and cresswell glycerin for the rochelle salt, in order to render the solution stable. some prepared by the writer over twelve months ago, according to the suggestion of the latter physician, has since shown no signs of decomposition, and is now as good as it was then. for qualitative purposes the solution may be prepared thus: dissolve gm. of recrystallized cupric sulphate and c.c. of pure glycerin in c.c. of distilled water. dissolve separately gm. of caustic soda in c.c. of water. mix the solutions and boil for a quarter of an hour. a small amount of reduction from impurity in the glycerin takes place. allow to stand till clear, decant, and dilute to , c.c. ten cubic centimeters will then equal roughly centigrammes of glucose. for exact quantitative determination it is necessary to standardize the solution with pure anhydrous dextrose. to a practiced operator the indications yielded by the use of this test are of great value; but beginners are exceedingly liable to mistake its various reactions, and to report the urine as saccharine when normal traces only of sugar are present. the bismuth test of bottger, as greatly improved by nylander, is fairly delicate, and not so easily misread as fehling's. a large volume of reagent being used with a comparatively small quantity of urine, the precipitate of earthy phosphates does not interfere in the least with the reaction. on boiling about drachms of nylander's solution and minims of urine for a minute or two, the liquid darkens with a trace of sugar, and becomes opaque and black if the latter is present in quantity. the reagent is prepared by dissolving grains of caustic soda, grains of rochelle salt, and grains of subnitrate of bismuth (free from silver) in fluid oz. of distilled water. it should be decanted for use from any sediment. [illustration: dr. pavy's apparatus.] in those cases where the amount of glucose present is required to be determined, dr. pavy's ammonia cupric process distances all compeers for ease of application and delicacy of end-reaction, combined with considerable accuracy. his solution differs from that of fehling in containing ammonia, which dissolves the cuprous oxide as soon as it is formed, yielding a colorless solution. it is only necessary, therefore, to note the moment that the blue color of the liquid is exactly discharged, in order to tell when all the copper present has been reduced. pavy's solution is prepared as follows: dissolve grains of rochelle salt and the same weight of caustic potash in distilled water; dissolve separately grains of recrystallized cupric sulphate in more water with heat. add the copper solution to that first prepared, and when cold add fluid oz. of strong ammonia (sp. gr. . ), and distilled water to fluid oz. the estimation is thus conducted: dilute c.c. of the ammoniated cupric solution--equivalent to milligrammes of glucose--with c.c. of distilled water, and place in a or oz. flask. attach this by means of a cork to the nozzle of an ordinary mohr's burette, _b_, preferably fitted with a glass stopcock, and filled previously with the diluted urine. the small tube, _c_, which traverses the cork is intended to permit the escape of steam. now raise the blue liquid in the flask to active ebullition--not too violent--by the aid of a spirit lamp or small bunsen flame. turn the stopcock in order to allow the urine to flow into the boiling solution at the rate of about drops per minute (not more or much less) until the azure tint is exactly discharged. then stop the flow, and note the number of cubic centimeters used. that amount of dilute urine will contain milligrammes of glucose. to render the determination as accurate as possible, the urine should be diluted to such an extent that not less than or more than c.c. are required to decolorize the solution, and the proportions necessary will be found to vary from part of urine in ½ to in or . the subsequent calculation is very simple. if you wish to give the percentage of sugar, multiply . by , and divide the product by the number of cubic centimeters of dilute urine employed. the figure thus obtained, multiplied by the extent of dilution--i.e., if there is of urine in , multiply by --gives the required percentage. the number of grains per fluid ounce can of course be obtained by multiplying the percentage by . . to observe easily the exact end-reaction a piece of white paper should be placed behind the flask. if the analyst objects to the escape of the waste ammoniacal fumes, they may be conducted by a suitable arrangement into water or dilute acid. in addition to glucose there are small quantities of other copper-reducing bodies present in all urine, which always render the reading higher than strict accuracy would demand. their aggregate proportion, however, is, comparatively speaking, so minute that for most medical purposes their presence may be disregarded. greater care must be exercised, though, in those instances where such a deoxidizer as chloral hydrate is accidentally present. in case of doubt, a little washed and pressed yeast should be allowed to stand with the urine for a day or two in a warm place. alcoholic fermentation with evolution of carbonic acid gas soon sets in, and the specific gravity of the liquid is lowered considerably. this reaction points conclusively to the presence of sugar. based upon braun's potassic picrate test, dr. g. johnson has devised a colorimetric process for the estimation of sugar. on boiling an alkaline solution of that salt with glucose, the former is reduced to deep red-brown picramate, the color of the liquid, of course, varying in intensity according to the proportion of sugar present. this solution is diluted till it corresponds in tint with a ferric acetate standard, and the percentage of sugar is then readily calculated. for those who prefer this process the convenient apparatus manufactured by mr. cetti, of brooke street, holborn, is recommended, who will also furnish full particulars of the test. albumen. normal urine is free from coagulable proteids, though it is admitted that albumen may sometimes occur in the absence of disease. it is always highly important, therefore, to determine accurately the presence or absence of this body. in the relentless malady named after richard bright, the urine always contains albumen, and if accompanied by the "casts" of the uriniferous tubules your report may amount to a sentence of certain death. the tests which we now describe are accurate and easily applied; but reliance should never be placed on any single reaction--at any rate until the operator has acquired considerable experience. galippe's _picric acid test_ has within the last few years attracted much attention, chiefly through the commendation it has received from dr. george johnson. a saturated solution is prepared by dissolving grains of recrystallized picric acid (carbazotic acid, or, more correctly, trinitrophenol) in pint of water with heat, and decanting the clear solution. some of the urine is rendered perfectly bright by filtration--repeated, if necessary--through good filtering paper, and to this an equal volume of the picric acid solution is added. in the presence of albumen a more or less distinct haze is produced, which on heating to the boiling point is rather intensified than otherwise. peptones, if present, yield a similar haze, and quinine or other alkaloid a more or less crystalline precipitate; but in both these cases the opalescence is completely dissipated by heat. mucin, an important constituent of some urines, is not affected by picric acid, and the test is decidedly one of great value. the _nitric acid test_. heller's contact method, which can also be used with the last-described reagent, is the best mode of applying the old-fashioned and favorite test with nitric acid. to volumes of a filtered saturated solution of magnesic sulphate, prepared by dissolving parts of the salt in parts of distilled water, add volume of strong nitric acid, and label "sir w. roberts' nitric acid reagent." a couple of drachms of bright filtered urine is allowed to float on an equal quantity of this solution in a test tube; care being taken that the contact line is sharply defined. in a period of time varying from a few seconds to a quarter of an hour, according to the amount of albumen present, a delicate opalescent zone forms at the point of junction, and if mucin also is present, a more diffused haze higher up in the urine. special attention should be given to the position of the opacity. in some concentrated urines a belt of urates will appear at the line of demarkation; but these dissolve on warming. moreover, owing to the dilution necessary in the mode of applying galippe's picric acid test, they are not so readily shown by the latter. a ½ oz. glass syringe can very conveniently be substituted for a test tube in making analyses according to heller's method. some of the urine should be drawn up, and then an equal volume of the reagent. on setting aside, the albumen ring will rapidly develop. the _boiling test_. this method also is very delicate and valuable. it depends on the well-known property possessed by many proteids of coagulating under the influence of heat. the urine should have an acid reaction to test paper; if alkaline, it must be cautiously neutralized with dilute acetic acid. in either case a single drop of strong acetic acid should be added to about three drachms of the bright liquid. if this precaution is omitted, there is danger of precipitating earthy phosphates on heating; and should a great excess of acid be employed, a non-coagulable form of albumen known as syntonin is formed, besides increasing the likelihood of precipitating mucin. place the prepared urine in a narrow test-tube and hold it in a small flame so that the upper part only of the liquid approaches the boiling point. by this means very small traces of albumen are easily observed, the opalescence produced contrasting strongly with the cold and clear fluid beneath. the _ferrocyanide test_. hydroferrocyanic acid yields a precipitate immediately in the presence of much albumen, and if traces only are present, in the course of a few minutes. to apply the test, strongly acidulate with acetic acid, and then add a few drops of recently prepared potassic ferrocyanide solution. this is one of the most delicate tests known. it is often desirable that the percentage of albumen present should be determined at frequent intervals, in order to note the success or otherwise of the physician's treatment. these quantitative determinations, being intended only for comparative purposes, do not demand any very excessive degree of accuracy, such as would be difficult to obtain in ordinary practice. the recent method of a continental worker. dr. esbach, affords indications sufficiently precise for therapeutical requirements, and is at the same time extremely easy of application. the filtered acid urine is poured into the glass tube up to the mark u, and then the special reagent is added till the level of the liquid stands at r. [illustration] mix the liquids thoroughly, without shaking, by reversing the tube a dozen times, close with a cork, and allow it to stand upright for twenty-four hours. the height at which the coagulum then stands, read off on the scale, will indicate the number of parts per thousand, or grammes of albumen in one liter. this divided by ten gives the percentage. dr. esbach's test solution is prepared by dissolving grammes of picric acid and grammes of citric acid in c.c. of boiling distilled water, and then adding, when cold, sufficient water to yield liter. the citric acid is only employed for the purpose of maintaining the acidity of the liquid, and is really not essential. uric or lithic acid. the determination of the proportion of uric acid in urine was formerly rather neglected by physicians. there is now, however, a growing tendency in a certain class of diseases to attach considerable importance to its accurate estimation, and, as some little trouble is involved, pharmacists should be prepared to undertake the work. a rough way is to concentrate somewhat, acidulate with hydrochloric acid, and collect and weigh the precipitate thrown down on standing. there are several objections, however, to this method, and many attempts have been made to elaborate a more reliable process. one of the most recent, and which has been pronounced the most practical and successful, has been devised by professor haycraft. although apparently rather detailed and elaborate, the determination is easy and extremely simple. the following solutions must be prepared: . dissolve grammes of nitrate of silver in c.c. of distilled water, and add ammonia until the precipitate first formed redissolves. . dilute strong nitric acid with about two volumes of distilled water; boil, to destroy the lower oxides of nitrogen, and preserve in the dark. . dissolve about grammes of ammonic thiocyanate (sulphocyanide) crystals in a liter of water, and adjust to decinormal argentic nitrate solution, by diluting till one volume is exactly equal to a volume of the latter. dilute the solution thus prepared with nine volumes of distilled water, and label "centinormal ammonic-thiocyanate solution." . a saturated solution of ferric alum. . strong solution of ammonia (sp. gr. . ). the uric acid estimation is conducted as follows: place per cent. of urine in a beaker with gramme of sodic bicarbonate. add or c.c. of strong ammonia, and then or c.c. of the ammoniated silver solution. if, on allowing the precipitate caused by the latter reagent to subside, a further precipitate is produced by the addition of more solution, the urine contains an iodide, and silver solution must be added till there is an excess. the gelatinous urate must now be collected, the following special procedure being necessary: prepare an asbestos filter by filling a oz. glass funnel to about one-third with broken glass, and covering this with a bed of asbestos to about a quarter of an inch deep. this is best managed by shaking the latter in a flask with water until the fibers are thoroughly separated, and then pouring the emulsion so made in separate portions on to the broken glass. on account of the nature of the precipitate and of the filter, it is necessary to use a sprengel pump, in order to suck the liquid through. the small apparatus sold to students by chemical instrument makers will answer the purpose admirably. having collected the precipitate of silver urate on the prepared filter, wash it repeatedly with distilled water, until the washings cease to become opalescent with a soluble chloride. now dissolve the pure urate by washing it through the filter with a few cubic centimeters of the special nitric acid. the process is carried out thus: add to the liquid in the beaker a few drops of the ferric-alum solution to act as an indicator, and from a burette carefully drop in centinormal ammonic thiocyanate until a permanent red coloration of ferric thiocyanate barely appears. the number of cubic centimeters used of the thiocyanate solution multiplied by . gives the amount of uric acid in the c.c. one milligramme may be added to compensate for loss, and the whole multiplied by four gives the percentage of uric acid in the urine. the whole process depends on the fact that argentic urate fails to dissolve in ammonia, but is soluble in nitric acid, and is thus easily obtained in the pure state. by determining the amount of combined silver, the percentage of uric acid can readily be calculated. the addition of sodic bicarbonate prevents the otherwise inevitable reduction of the silver salt. bile. in diseases affecting the liver, the urine frequently becomes contaminated with biliary constituents. if the coloring matter of bile is present (_bilirubin_, etc.), the liquid is darkened considerably in tint, and may assume various shades of brown or green. should the color be decided, the fluid will be found to foam strongly on shaking, and white blotting-paper will be stained by it yellow or greenish. these characters point to the presence of bile in fair quantity, and it is only necessary to apply a single confirmatory test. allow some of the urine to flow carefully, according to heller's method, over a couple of drachms of yellow nitric acid (i.e., acid containing traces of the lower oxides of nitrogen). a number of rapidly changing colors soon appear, passing through green, blue, violet, and red to yellow. the first of these tints, green, is the only one that undoubtedly points to the presence of biliary coloring matter, all the others being yielded by another constituent of urine, indican, when similarly treated. should the color of the urine suggest the presence of only traces of bile, the best plan is not to treat the urine directly, but extract a quantity of it by shaking with chloroform. on separating the latter, and covering with yellowish nitric acid, the color changes will be observed penetrating into the chloroform. a little, also, evaporated on a slide yields reddish crystals, which exhibit a pretty play of colors under the microscope when touched with nitric acid. it is not unfrequently considered important to test urine for the sodium salts of the conjugate biliary acids, taurocholic and glycocholic. dr. oliver, of harrogate, has proposed the use of an acidulated peptone solution for this purpose, and the reaction is undoubtedly a good one. the reagent is prepared by dissolving grains of flesh peptone, grains of salicylic acid, and minims of strong acetic acid, in sufficient water to produce fluid oz. of solution. thus prepared, the peptone shows no signs of decomposition on keeping. to use the test, mix fluid drachm of the reagent with minims of urine, previously diluted to a standard specific gravity of . . a haze is produced, which will be found to be more or less distinct, according to the proportion of bile salts present. chlorides. a normal and variable constituent of urine, chlorine, is not usually required to be determined. should the estimation be considered necessary, however, volhard's silver process, which has been noticed in treating of uric acid, possesses several advantages over other methods: c.c. of urine are diluted with c.c. of distilled water. to this is added c.c. of pure percent. nitric acid and c.c. of a standard solution of silver nitrate ( c.c. = . gramme nacl). shake well and make up to c.c. with water. all the chlorine present will now be precipitated in the liquid as a silver salt. filter an aliquot part (about or c.c.), and determine in the clear solution the excess of silver with standard ammonic thiocyanate, using the ferric alum indicator. the difference between this and the amount of silver originally present in the aliquot part has been precipitated as silver chloride (agcl). the whole estimation should be conducted as rapidly as possible. a simple calculation will then give the proportion of chlorine in the dilute urine, and this multiplied by ten shows the percentage. it is usual to report in terms of nacl. phosphates. in those cases where the pharmacist is asked to determine phosphoric acid quantitatively, the uranic-acetate method described in sutton's "volumetric analysis" yields the most satisfactory results. the process requires some little experience to use it with ease, and is too lengthy for quotation here. microscopical examination. a good microscope is one of the first necessaries of the urinary analyst. by its aid it is possible to distinguish easily many solid constituents of urine--normal and pathological; indeed, the examination of urinary deposits is often quite as important as the more elaborate wet analysis. a well-made instrument is no luxury to the pharmacist; but even those whose chief aim is _bon marché_ can procure capital students' microscopes at exceedingly low cost. one of the cheapest, and at the same time an instrument of good quality, is the "star," manufactured by messrs. r. & j. beck, of cornhill, e.c. equipped with a good microscope, the analyst should obtain a fair supply of typical slides for comparison. the following selection will be found sufficient for his purpose: a set of the chief varieties of uric acid, calcic oxalate, and triple phosphate; the urates and oxalurates; urea nitrate, calcic hippurate and carbonate, hippuric acid, cystin, well mounted "casts" of the _tubili uriniferi_, spermatozoa, etc. in doubtful cases microchemical reagents can be employed, using professor attfield's "chemistry" as a guide. where mounted objects are not at hand, reference may be made to the capitally executed plates in that work. after obtaining a little experience in the use of the microscope, no difficulty will be met with in these examinations.--_the chemist and druggist._ * * * * * liquid and gaseous rings. all who have learned a little of chemistry doubtless remember the experiment with vortex rings produced by phosphorus trihydride mixed with a little phosphide of hydrogen. as this curious phenomenon evidently does not depend upon the peculiar properties of this gas, i have been trying for some time to reproduce it by means of tobacco smoke, and even with chemical precipitates, which are, in a way, liquid smoke. after a few tentatives made at different times, my experiment succeeded perfectly. the following is, in brief, the mode of operating: take up a little hydrochloric acid in a pipette and put a few drops of it into a very dilute solution of nitrate of mercury, and you will obtain rings of mercurial chloride that will, in their descent, take on the same whirling motion that characterizes the aureolas of phosphureted hydrogen. the drops of acid should be allowed to fall slowly, and from a feeble height, to the surface of the liquid contained in the vessel. it is unnecessary to say that the result may be obtained through the use of other solutions, provided that a precipitate is produced that is not very thick, for in the latter case the rings do not form. if need be, we may have recourse to milk, and carefully pour a few drops of it into a glass of water. [illustration: fig. .--production of smoke rings.] as regards smoke rings, it is easy to produce these by puffing cigar smoke through a tube (fig. ). but, in order to insure success, a few precautions are necessary. the least current of air must be avoided, and this requires the closing of the windows and doors. moreover, in order to interrupt the ascending currents that are formed in proximity to the body, the operation should be performed over a table, as shown in the figure. the rings that pass beyond the table are not perceptibly influenced by currents of hot air. a tube ¾ inch in diameter, made by rolling up a sheet of common letter paper, suffices for making very beautiful rings of one inch or more in diameter. in order to observe the rings well, it is well to project them toward the darkest part of the room, or toward the black table, if the operator is seated. the first puffs will not produce any rings if the tube has not previously been filled with smoke. the whirling motion is perfectly visible on the exit of the ring from the tube, and even far beyond. [illustration: figs. , , and .--various aspects of smoke rings.] as for the aspect of the rings projected with more or less velocity to different distances from the tube, figs. , , and give quite a clear idea of that. figs. and show the mode of destruction of the rings when the air is still. there are always filaments of smoke that fall after being preceded by a sort of cup. these capricious forms of smoke, in spreading through a calm atmosphere, are especially very apparent when the rays of the sun enter the room. very similar ones may be obtained in a liquid whose transparency is interfered with by producing a precipitate or rings in it.--_la nature._ [illustration: figs. and ..--smoke rings breaking up.] * * * * * shall we have a national horse? _to the editor of_ scientific american supplement: in your issue for august is "a proposition for a government breeding farm for cavalry horses," by lieutenant s.c. robertson u.s.a., first cavalry. the article is national in conception, deep in careful thought, which only gift, with practical experience with ability, could so ably put before the people. as a business proposition, it is creditable to an officer in the united states army. the husbandman and agriculturist, also the navy and scientific explorations, each in turn present their wants before the government for help in some way, and receive assistance. the seaman wants new and improved or better ships, and the navy gets them; but the poor cavalryman must put up with any kind of a craft he can get; the horse is the cavalryman's ship--war vessel on land. the appeal of lieut. robertson to our government for better horses is reasonable; and he tries to help the government with a carefully studied business proposition through which to enable our government to grant the supplication of the army. that lieut. robertson loves a horse, and knows what a good one is, no man can dispute who has read his article; but as to how it can best be produced, he does not know. while i for one applaud both his article and his earnestness, with your permission i will make some suggestions as to the breeding side of his proposition. the business portion will, of course, come under the ordnance department in any event. as for a government breeding establishment for any kind of livestock in this great agricultural country, i feel that such would be at variance with the interests of husbandry in america. the breeding of horses is particularly an important branch of agriculture, and the farmers should be assisted by the government in the improvement of their horses, until they are raised to a standard which in case of emergency could supply the army at a moment's notice with the best horses in the world at the least possible expense. our government agricultural bureau is constantly spending thousands of dollars to help the agriculturist in matter of better and greater varieties of improved seeds and the better way for cultivation. now, the seed of animal life is as important as in vegetable life to the interest and welfare of the husbandman, which also means the government. for the government to become a monopolist of any important branch in agriculture is not in harmony with the principles of our republican-democratic form of government. while advocating a protective tariff against outside depreciation of home industries, our government should not in any way approach monarchical intrusion upon the industries of its husbandmen. our government cannot afford to make its agriculturists competitors in so important a matter to them (the farmers) as in the raising of horses; but the government can see to it that the husbandman has a standard for excellence in the breeding of horses which shall be recognized as a national standard the civilized world over. then, by that standard, and through our superior advantages over any other civilized nation in the vast extent of cheap and good grass lands, with abundance of pure water, and with all temperatures of climate, we can grow, as a people, the best horses in the world, to be known as the national horse of america. our government must have a blood standard for the breeding of horses, by which our horses can be bred and raised true to a type, able to reproduce itself in any country to which we may export them; and the types can be several, as our territory is so great and demands so varied, but blood and breeding must be the standard for each type. our fancy breeders have a standard now, called a "time standard," which is purely a gambling standard, demoralizing in all its tendencies to both man and beast. with this the government need have nothing to do, for it will die out of itself as the masses learn more of it, and especially would it cease to be, once the government established a _blood_ standard for the breeding of all horses, and particularly a national horse. when the cereal crops of our country are light, or the prices fall below profitable production, the farmer has always a colt or two to sell, thus helping him through the year. in place of constantly importing horses from france, england, and scotland, where they are raised mostly in paddocks, and paying out annually millions of dollars, it is our duty to be exporting. as an american i am ashamed when i see paraded at our county or state fairs stallions and mares wearing the "blue ribbon" of superexcellence, with boastful exclamation by the owner of "a thoroughbred imported percheron, or a thoroughbred imported french coacher, or a thoroughbred imported scotch clyde, or a thoroughbred imported english coacher, or a thoroughbred imported english shire, or a thoroughbred imported english cleveland bay!" the american farmer and his boys look on aghast at the majesty and beauty of these prize winners over our big-headed, crowbar-necked, limp-tailed, peeked-quartered horses called "standard bred!" what standard? "time standard," as created by a man who is neither a horseman nor a breeder; but because of the lack of intelligent information and want of courage upon the part of a few, this man's _ipse dixit_ has become law for the american breeders until such time as cultured intelligence shall cause them to rebel. it soon will. it is indeed time for the government to step in and regulate our horse breeding. of all the national industries there is none of more importance than that of horses. more so in america than in any other country, because our facilities are greater, and results can be greater under proper regulation. lieut. robertson has proved to be the right man in the right place, to open the door for glorious results to our nation. no one man or a small body of men can regulate this horse-breeding industry, but as in france, russia, and england, the government must place its hand and voice. we are indeed an infant country, but have grown to an age where parental restraint must be used now, if ever. we have millions of farmers in america, breeding annually millions of horses; and except we have another internal war, our horses will soon become a burden and a pest. there are numbers of rich men throughout the country breeding fancy horses, for sport and speculation, but they only add to the increasing burden of useless animals, except for gambling purposes; for they are neither work horses, coach horses, nor saddle horses. our farmers of the land are the breeders, as our recent war of the rebellion testified. the war of , the mexican war of , and the war of each called for horses at a moment's notice, and our farmers supplied them, destroying foundation bloods for recuperation. from to the noble patriotism of our farmers caused them to vie with each other as to who should give the best and least money to help the government; and cannot our government now do something for the strength and sinew of the land, the farmers? i was dealing in horses, more or less, from to (as i had been before and long after), and many was the magnificent horse i saw led out by the farmer for the government, at a minimum price, when, previous to , $ , $ , and even $ was refused for the same animals. horses that would prove a headlight to any gentleman's coach in the city, and others that would trot off fourteen to sixteen miles an hour on the road as easy as they would eat their oats, went into the cavalry or artillery or to baggage trains. what were left for recuperation at the close of the war were mongrels from canada or the indian and wild lands of the west, and such other lazy brutes as our good farmers would not impose upon the government with or later were condemned by the army buyers. these were largely of the abdallah type of horse, noted for coarseness, homeliness, also soft and lazy constitutions. no one disputes the brute homeliness of the abdallah horse, and in this the old and trite saying of "like begets like" is exemplified in descendants, with which our country is flooded. the speed element of which we boast was left in our mares of arabian blood through clay and morgan, but was so limited in numbers as to be an apology for our present time standard in the breeding of fancy horses. knowing that abdallah blood produced no speed, and being largely ignorant as to the breeding of our mares, which were greatly scattered over the land after the war, some kind of a guess had to be made as to the possibility of the colts we were breeding, hence the time standard fallacy. but it has ruined enough men, and gone far enough. upon lieutenant robertson's proposition, a turn can be made, and a solid base for blood with breeding of all american horses can be demanded by the government for the country's good. from the earliest history of man, as a people increased in wealth, they gave attention to mental culture with refinement; following which the horse was cultivated to a high _blood_ standard with national pride. from the egyptians, the moors, the romans, and britons to france, russia, and prussia we look, finding the horse by each nation had been a national pride--each nation resorting to the same primitive blood from which to create its type, and that primitive was the arabian. scientists have theorized, men have written, and boys have imagined in print, as to some other than the arabian from which to create a type of horse, and yet through all ages we find that arabian has been the one stepping stone for each advanced nation upon which blood to build its national horse. scientists have reasoned and explored, trying to prove to the contrary, but what have they proved? the arabian horse still remains the fact. the lion, the tiger, the leopard, still remain the same, as does the ass and the zebra. as god created and man named them, with all animal life, subject to the will of man, so do they all continue to remain and reproduce, each true to its type, free from imperfections or disease; also the same in vegetable and mineral life. in animal life, the build, form, color, size, and instincts remain the same, true to its blood from the first, and yet all was created for man through which to amuse him and make him work. it is a fact that all of man's creations from any primitive life, either animal or vegetable, will degenerate and cease to be, while of god's perfect creations, all continue the same. we will condense on the horse. the arabian is the most pliable in its blood of any other known to man. from it, any other type can be created. once a type has been created, it must be sustained in itself by close breeding, which can be continued for quite a number of years without degeneracy. for invigoration or revitalizing, resort must be made to its primitive blood cause. to go out of the family to colder or even warmer creations of man means greater mongrelization of both blood and instinct, also to invite new diseases. nothing is more infatuating than the breeding of horses. a gifted practical student in the laws of animal life may create a new and fixed type of horse, but it can be as quickly destroyed by the multitude, through ignorant mongrelization. in the breeding of horses, our people are wild; and in no industry can our government do more good than in making laws relating to their breeding. it can father the production of a national horse without owning a breeding farm. it can make _blood_ and _breeding_ a standard for different types, and see to it that its laws are obeyed, thus benefiting all the agriculturists, and have breeding farms in america; and also itself as a government, financially. we must not however begin upon the creation of other nations, but independently upon god's gift to man, as did england, france, and russia. that a government should interfere in the breeding of horses is no new thing. the arabs of the desert boast to this day of king solomon's stud of horses; but in each and every instance where a nation has regulated and encouraged the breeding of the horse to a high standard of excellence, they have all begun at the primitive, or arabian. thus england in boasting of her thoroughbred race horse admits it to be of arabian origin. russia in boasting of her orloff trotting and saddle horse tells you it is of arabian origin. france boldly informs you that her percheron is but an enlarged arabian, and offers annual special premiums to such as revitalize it with fresh arabian blood. after the war of our forefathers imported many arabian stallions to recuperate the blood of their remnants in horses. from such prominent men as andrew jackson and henry clay said all they could by private letter and public speech to encourage the importation of and breeding freely to the arabian horse, and specially did the state of kentucky follow the advice of henry clay, so that from up to kentucky had more arabian stallions in her little district than the combined states of the union. kentucky has had a prestige in her mares since the war, and it comes in the larger amount of arabian blood influence she has had in them, than could be found elsewhere. kentucky is shut in, as it were, and retaining her mares largely impregnated with arabian blood, all that was necessary for them to do was to get trotting-bred stallions from new york state, then eclipse all other states in the produce. while i cheerfully award to kentucky all credit due to it, i am not willing that lieut. robertson should make his base for government breeding establishment sectional, nor would i submit to england through kentucky. i am too american for that. for cavalry purposes, the prussian horse is the best in the world, and is also arabian in its closest foundation. to get at this blood question more definitely, let us inquire into these different recognized self-producing national types of horses abroad. first is the english thoroughbred race horse, which is simply an improved arab. the functions of this english national horse are but twofold--to run races and to beget himself, after which he ceases to be of value. he is not a producer of any other type of value; to breed him out of his family is mongrelism and degeneracy, so we don't want him, even though we could humiliate our american pride through our loved state of kentucky. count orloff of russia was a great horseman, exceedingly fond of horseback riding independent of the chase. he tried in to breed a satisfactory horse from the english thoroughbred race horse, but went from bad to worse until he resorted to the ever-pliant blood of the arabian. he sent to egypt and secured a thoroughbred arabian stallion, paying $ , for him (in our money). this horse he bred to danish mares, largely of arabian blood, and created a very stout, short-backed horse, standing from ½ to ¾ and hands high, of great trotting speed, also able to run to weight, and with good disposition, which the english thoroughbred did not have. this type he continued to close-breed, going back to the arabian for renewed stoutness. at his death, his estates passed to his daughter, who continued her father's breedings until the russian government purchased the entire collection, about , since when the russian government orloff trotting and saddle horse has become famous the world over as a first-class saddle, cavalry, stage coach, and trotting horse combined. they are broken at three years of age, and scarce any that cannot beat : at trotting speed, and from that down to : in their crude way of hitching and driving. this is something for american breeders to think very interestedly upon. france wanted heavy draught horses, also proud coach horses; so rather than go to any competing nation for their created types, her enterprising subjects took the same arabian blood, and from it created the beautiful percheron, also french coach horses, so greatly valued and admired the world over, and which the gifted and immortal rosa bonheur has so happily reproduced upon canvas. can america show any kind of a horse to tempt her brush? with regard to a foundation for a government or national horse, i am certain so gifted and able united states officer as mr. s.c. robertson did not know that it was unnecessary to go to england for the blood of their national horse, even though we smuggled it through kentucky or any other of our states. again, it would be impossible to produce any type of a horse from the english thoroughbred, except a dunghill, and mr. robertson would not have his government breed national dunghills! i love england as our mother country, but am an american, born and dyed in the wool to our independence, from the "declaration." now let us see what england says of her thoroughbred: "he is no longer to be relied upon for fulfilling his twofold functions as a racer and reproducer of himself. he is degenerating in stoutness and speed. as a sire he has acquired faults of constitution and temper which, while leaving him the best we have, is not the best we should aspire to have. his stoutness and speed are distinctly arabian qualities, to which we must resort for fresh and pure blood." we have shown that the englishman says "his thoroughbred is full of radical and growing defects in wind, tendons, feet, and temper, and that his twofold functions are to run races and reproduce himself, which are the end of his purpose." does our government want breeding farms upon which to nurse these admitted "defects," including the "confirmed roarer," for cavalry horses? i quote again: "those who have had most to do with him are ready to admit that he no longer possesses the soundness, stoutness, speed, courage, and beauty he inherited from his arabian parentage. as a sire for half-bred stock, he may do for those who will use him, but we must resort to the arabian if we would revitalize and sustain our thoroughbred race horse." in the face of these statements, in print abroad, would lieut. robertson make the base for our proposed national horse that of the english thoroughbred, scattering the weeds from such imperfect breedings among the farmers of our land? i am writing as an old horseman and breeder, and not as a newspaper man or young enthusiast, although the enthusiasm of youth is still in me, for which i am thankful. this question of horse breeding i have been deeply interested in for forty years past. let me quote to the reader from one of many letters i have received from sir wilfrid seawen blunt during the past seven years. his practical knowledge of the english thoroughbred race horse and his blood cause, the arabian, is the equal if not superior to any other one man of this present age. with his wife, lady anne, he dwelt with the different tribes of the desert, studying the arabs as a people, in their customs and habits, also traditions with beliefs. in matter of their horses, mr. blunt made a special study, while lady anne put her diaries in book form after her return, and which book should be owned by every cultured and educated lady in america. after spending a year in arabia, traveling both sides of the euphrates and through mesopotamia, as no other anglo-saxons have been known to do, living with the different bedouin tribes of the desert as they lived, mr. blunt and his wife, lady anne, came out with sixteen of the choicest bred mares to be found, also two stallions, the mares mostly with foal. these were placed upon their estates, "crabbet park," to continue inbreeding as upon the desert, pure to its blood. as this question in itself will make a long and interesting article, i will avoid it at present, quoting to the reader from one of my old letters: "crabbet park, sussex, england. "dear sir: political matters have prevented an earlier reply to your last. "i am well satisfied with my present results, and shall not abandon what i have undertaken. the practical merits of arabian blood are well understood by us. "our sale of young stock maintains itself in good prices in spite of bad times; indeed, my average within the past two years has risen from £ to £ on the pure-breds sold as yearlings, and we receive the most flattering and satisfactory accounts from purchasers, although it is known that i retain the best of each year's produce, and so have greatly improved my breeding stock. "you speak of the opinions of the press as against you. the sporting press are not breeders, but are the mouthpiece of prejudices. we have had them somewhat against us, but they now view things in more friendly tone. "for immediate use in running races (in which the sporting press are chiefly interested), the arabian in his undeveloped state and under size will not compete with the english race horse. this fact has caused racing men to doubt his other many and more important merits; indeed, it is only those who have had personal experience of him that as yet acknowledge them. "the strong points in the arabian are many: "_first_, his undoubted soundness in constitution, in _wind_, _limb_, and _feet_. it will be noticed that the englishman must have soundness in wind, limb, and feet, showing that their thoroughbred is the thorn in that particular. the arabian has also wonderful intelligence, great beauty, and good disposition, with an almost affectionate desire to adapt himself to your wishes. "in breeding, i have found the pure-breds delicate during the first few weeks after birth, and have lost a good many, especially those foaled early in the year; yet it is a remarkable fact that during the eight years of my breeding them, i have had no serious illness in the stables; once over the dangerous age, they seem to have excellent constitutions, and are always sound in _wind_, _limb_, and _feet_. "_second_, they are nearly all good natural and _fast walkers_, also fast trotters; and from the soundness of their feet are especially fitted for fast road work, being able to do almost any number of miles without fatigue. "_third_, they are nearly all good natural jumpers, and i have not had a single instance of a colt that would not go across country well to hounds. "they are very bold fencers, requiring neither whip nor spur. they carry weight well, making bold and easy jumps where other larger horses fail. "_fourth_, they have naturally good mouths, and good tempers, with free and easy paces; so that one who has accustomed himself to riding a pure-bred arabian will hardly go back, if he can help it, to any other sort of horse. "there is all the difference in riding the arabian and the ordinary english hunter or half-bred that there is in riding in a well-hung gig or a cart without springs. "_fifth._ as sires for half-bred stock, the arabian may not be better than a _first-class_ english thoroughbred, but is certainly better than a _second_-class one, and _first_-class sires are out of the reach of all ordinary breeders; for that reason i recommend a fair trial of his quality, confident your breeders will not be disappointed. "with good young mares who require a horse to give their offspring quality, that is to say, beauty, with courage and stoutness, and with a turn of speed for fast road work, the arabian is better than any class of english thoroughbreds that are used for cross breeding. "i trust then for that reason you will not allow yourself to be discouraged by the slowness of the people to appreciate all the merits of the arabian at once. "our breeders are full of prejudices, and only experience can teach them the value of things outside their own circle of knowledge. "i have no doubt whatever that truth will in the end prevail; but you must have patience. remember that a public is always impatient, and most often unreasonably so. "my stud i keep at a permanent strength of twelve brood mares, and as many fillies growing in reserve. "you ask me regarding the _pacing_ gait. i have seen it in the pure-bred arabs on the desert; and in many parts of the east it is cultivated, notably in asia minor and barbary. the walk, pace, amble, trot, and run are found in the arabian, and either can be cultivated as a specialty. "if you think any of my letters to you are of general value to your people, i am quite willing you should so use them. "i am, very truly yours, "wilfrid scawen blunt. "to randolph huntington, rochester, n.y." my experience with arabian blood the past seven years justifies all that mr. blunt has predicted to me from time to time. so also do old letters by andrew jackson and henry clay hold out the same inducements to the breeders of kentucky and tennessee in their day. from my long years of experience in all classes of horses, i am frank to say to-day that i would not be without a thoroughbred arabian stallion on my place, and journalists who inform their readers that they "are liable to splints, ringbones, and spavins," give themselves away to all intelligent readers and breeders as exceedingly superficial in matter of horses; for ringbones and spavins are positively unknown among the arabs. the way to get rid of such imperfections in our mongrel breed of horses is to fill them up with pure arab blood. such paper men also talk about "_fresh diomed_" and "fresh messenger blood," as though there had been a drop of it in never so diluted form for any influence these many years, of course forgetting that _diomed_ was a very strongly _inbred arabian_ horse. he came to this country when years old. he was foaled , and arrived in virginia in . from his old age and rough voyage in an old-fashioned ship, it required nearly a year to recuperate from the journey, and was years old before he could do stud service to any extent. then, at no time to his death was he a sure foal getter, even to a few mares. he died in , thirty-one years old, long enfeebled and unfit for service. between and is quite a period of time, during which we have had four different wars, beginning with , and how much diomed blood does the reader suppose there is in this country? yet i take up daily and weekly papers devoted to horse articles, extolling the value of _diomed_ blood as cause for excellence in some young horse. are we a nation of idiots to be influenced by such nonsense? i wish there was fresh diomed blood; thus the public would know what arab blood had done for england. so i can say of imported messenger. what our breeders want is good, solid information in print, and not the; dreamings of some professional writer for money. for myself, i am on the downhill side of life, but so long as i can help the young by pen or example, i shall try. randolph huntington. rochester, n.y. * * * * * scenes among the extinct volcanoes of rhineland. in the province of the rhine there is a range of mountains, including several extinct volcanoes, which offer grand and beautiful scenery and every opportunity for geological study, leading the mind back to the early ages of the earth. let us take an imaginary trip through this region, starting on our wanderings from the rhine, where it breaks through the vine-clad slate mountains of the westerwald and the eifel. a short distance above the mouth of the ahr we leave its banks, turning to the west, and entering the mountains at the village of nieder breisig. a pretty valley leads us up through orchards and meadows. the lower hills are covered with vineyards and the mountains with a dense growth of bushes, so that we do not obtain an extended view until we reach an elevated ridge. [illustration: distant view of the volcanic portion of the eifel, taken from the heights of the schneifel.] the valley of the rhine lies far below us, but the glittering surface of the river, with the little towns, the castles and villas and the gardens and vineyards on its banks are still visible, while in the background the mountains of the westerwald have risen above the hills on the river. this range stretches out into a long wooded ridge crowned by cone-shaped peaks of basalt. to the northwest of this lies siebengebirge, with its numerous domes and pinnacles, making a grand picture veiled in the blue mist of distance. on the opposite side we have a very different view of curious dome and cone shaped summits surrounded by undulating plateaus or descending into deep ravines and gorges. it is the western part of the volcanic region of rhineland which lies before us, and in the center of which is the laachersee or lake of laach. the origin of these volcanoes is not as remote as many suppose, but their activity must have continued for a comparatively long period, judging from the extent of their lava beds. [illustration: the shores of laachersee.] there was a time when the sea covered the lowlands of north germany, and the waves of a deep bay washed the slopes of the siebengebirge. then the bed of the rhine lay in the highlands, which it gradually washed away until the surface of the river was far, far below the level of its old bed; and then the volcanoes poured forth their streams of lava over the surrounding plains. in the course of time the surface of the country has changed so that these lava beds now lie on the mountain sides overhanging the valleys of to-day. some of the volcanoes sent forth melted stones and ashes from their summits, and streams of lava from their sides, while the craters of others cracked and then sank in, throwing their debris over the neighboring country. in the eifel there are many such funnels which now contain water forming beautiful lakes (maaren), which add much to the scenery of the eifel. the laachersee is the largest of these lakes. in the mean time the channel of the rhine had been worn away almost to its present level, but the mountains still sent forth their streams of lava, which stopped brooks and filled the ravines, and even the rhine itself was dammed up by the great stream from fornicherkopf forming what was formerly the neuwied. the old lava stream which obstructed the river is still to be seen in a towering wall of rock, extending close beside the road and track that follow the shore. [illustration: crater and lake on top of the mosenberge.] after having made these observations, we descend from the height which afforded us the view of the vinrt valley. a clear brook flows through green meadows and variegated fields stretch along the mountain sides, while modest little villages are scattered among the fruit trees. on the other side of the valley rises the herchenberg, an extinct volcano. as we climb its sides we see traces of the former devastation. loose ashes cover the ground, bits of mica glittering in the sun, and on the summit we find enormous masses of stone which were melted and then baked together. in the center lies the old crater, a quiet, barren place bearing very little vegetation, but from its wall an excellent view of the surrounding country can be obtained. not far from this mountain lies the mighty bausenberg, with its immense, well preserved crater, only one side of which has been broken away, and which is covered with a thick growth of bushes. the ledges of this mountain are full of interest for the mineralogist. nearer to lake laach are the wahnenkopfe, the proud veitskopf, and other cone-shaped peaks. to these we direct our steps, and after a long tramp over the rolling, cultivated plateau, we climb the wood-covered sides of the great basin in whose depths the laachersee lies. from the shore of this lake rise the high volcanic peaks which tower above all the other mountains. [illustration: lake gemunden.] tired from our climb through the ashes, which are heated by the sun, we rest in the shade of a beech-wood, looking through the leaves into the valley below us, with the old cloisters and the high roman church which the monks once built on the banks of the lake. [illustration: the crater of the herchenberges.] to the south of the lake rise other volcanoes, lying on the border of the fertile maifeld, which gradually descends to the valley of neuwied. here, at the southern declivity of the group of volcanoes which surrounds the laachersee, remarkably large streams of lava were ejected, covering the surface of the plateau with a thick layer. the largest of these streams is that from the niedermendig, which consists of porous masses of nepheline lava. in the time of the romans millstones were made from this mass of rock, and the industry is carried on now on a larger scale. it is a strange sight which meets one's eyes when, after descending through narrow passages, he finds himself in large, dark halls, from which the stone has been cut away, and in which there are well-like shafts. the stones are raised through these shafts by means of gigantic cranes and engines. because of the rapid evaporation of the water in the porous stone, these vaults are always cool, winter and summer, and therefore they are used by several brewers as storehouses for their beer, which owes its fame to these underground halls. [illustration: the millstone galleries in the lava beds of niedermendig.] [illustration: on the lava beds of niedermendig.] although the traces of former volcanic action are evident to the student of nature, the rhine with its mild climate and luxuriant vegetation has covered many marks of the former chaotic state of the land. very little of this beauty is seen on the higher and, therefore, more severe and barren mountains of the western eifel, through which a volcanic fissure runs from the foot of the high unhospitable schneifel to bertrich baths, near the moselle. from the ridge of the schneifel the traveler from the north has his first glimpse of the still distant system of volcanoes. the most beautiful part of this portion of the eifel is in the neighborhood of dann and manderscheid. near the former rises a barren mountain with a long ridge, on each side of which is a deep basin. these are sunken craters, which now contain lakes, and near these two there is a third, larger lake, the maar von schalkemehren, on the cultivated banks of which we find a little village. the middle one, the weinfelder maar, is the most interesting for geologists, for there seems to have been scarcely any change here since the time of the eruption. on the other side of the mountain lies the gremundener maar, the shores of which are not barren and waste land, like those of the middle lake, but it is surrounded by a dark wreath of woods whose tops are mirrored in the crystal water. farther to the south, near the villages of gillenfeld and meerfeld, there are more lakes. [illustration: the weinfelder lake on the mauseberge.] [illustration: eastern declivity of mosenberge near manderscheid.] the grandest picture of these ancient events is offered by the mosenberg, near manderscheid, a mighty volcano which commands an extensive view of the country. two old craters lie on its double top, one of which has fallen in, forming a short rocky valley, but the other retains its original regular shape. in the circular funnel, whose walls consist of masses of lava stone, rests a quiet, black lake, that looks very mysterious to the wanderer. only low juniper bushes grow near the crater, bearing witness to the barrenness of the land. from the foot of this mountain an immense stream of lava, as wide and deep as a glacier, broke forth and flowed into the valley, where the end of the stream is still to be seen in a high, steep wall of rock. [illustration: the "cheese grotto" at bertrich baths.] similar sights are met all through this western volcanic region, and we can consider the mineral and acid springs, which are very numerous, as the last traces of the former disturbances, the products of the decomposition of the volcanic stones buried in the earth. at bertrich baths there are hot springs which were known to the romans, for numerous antiquities dating from their time have been excavated here. near these springs, at bertrich, there is a "cheese grotto," which is a break through the foot of a stream of lava, the stones of which have not assumed the usual form of solidified columns, but have taken flat, round shapes which resemble the forms of cheeses. now we have completed our wanderings, which required only a few days, although they extended over this whole volcanic region, and which end here on the moselle.--_ueber land und meer; allgemeine illustrirte zeitung._ * * * * * [nature.] the "meteorologiske institut" at upsala, and cloud measurements. the meteorological institute at upsala has gained so much fame by the investigations on clouds which have been carried on there during the last few years, that a few notes on a recent visit to that establishment will interest many readers. the institute is not a government establishment; it is entirely maintained by the university of upsala. the _personnel_ consists of prof. hildebrandsson, as director; m. ekholm and one other male assistant, besides a lady who does the telegraphic and some of the computing work. the main building contains a commodious office, with a small library and living apartments for the assistant. the principal instrument room is a separate pavilion in the garden. here is located thiorell's meteograph, which records automatically every quarter of an hour on a slip of paper the height of the barometer, and the readings of the wet and dry thermometers. another instrument records the direction and velocity of the wind. this meteograph of thiorell's is a very remarkable instrument. every fifteen minutes an apparatus is let loose which causes three wires to descend from rest till they are stopped by reaching the level of the mercury in the different tubes. when contact is made with the surface of the mercuries, an electric current passes and stops the descent of each wire at the proper time. the downward motion of the three wires has actuated three wheels, each of which carries a series of types on its edge, to denote successive readings of its own instrument. for instance, the barometer-wheel carries successive numbers for every five-hundredth of a millimeter-- . , . , . , etc.; so that when the motion is stopped the uppermost type gives in figures the actual reading of the barometer. then a subsidiary arrangement first inks the types, then prints them on a slip of paper, and finally winds the dipping wires up to zero again. an ingenious apparatus prevents the electricity from sparking when contact is made, so that there is no oxidation of the mercury. the mechanism is singularly beautiful, and it is quite fascinating to watch the self acting starting, stopping, inking, and printing arrangements. we could not but admire the exquisite order in which the whole apparatus was maintained. the sides of the various glass tubes were as clean as when they were new, and the surfaces of the mercuries were as bright as looking glasses. the university may well be proud that the instruments were entirely constructed in stockholm by the skillful mechanic sorrenson, though the cost is necessarily high. the meteograph, with the anemograph, cost £ , but the great advantage is that no assistant is required to sit up at night, and that all the figures wanted for climatic constants are ready tabulated without any further labor. but the institute is most justly celebrated for the researches on the motion and heights of clouds that have been carried on of late years under the guidance of prof. hildebrandsson, with the assistance of messrs. ekholm and hagström. the first studies were on the motion of clouds round cyclones and anticyclones; but the results are now so well known that we need not do more than mention them here. latterly the far more difficult subjects of cloud heights and cloud velocities have been taken up, and as the methods employed and the results that have been obtained are both novel and important, we will describe what we saw there. we should remark, in the first instance, that the motion of the higher atmosphere is far better studied by clouds than by observations on mountain tops, for on the latter the results are always more or less influenced by the local effect of the mountain in deflecting the wind and forcing it upward. the instrument which they employ to measure the angles from which to deduce the height of the clouds is a peculiar form of altazimuth that was originally designed by prof. mohn, of christiania, for measuring the parallax of the aurora borealis. it resembles an astronomical altazimuth, but instead of a telescope it carries an open tube without any lenses. the portion corresponding to the object glass is formed by thin cross wires: and that corresponding to the eye piece by a plate of brass, pierced in the center by a small circular hole an eighth of an inch in diameter. the tube of the telescope is replaced by a lattice of brass work, so as to diminish, as far as possible, the resistance of the wind. the vertical and horizontal circles are divided decimally, and this much facilitates the reduction of the readings. the general appearance of the instrument is well shown in the figure, which is engraved from a photograph i took of mr. ekholm while actually engaged in talking through a telephone to m. hagström as to what portion of a cloud should be observed. the latticework tube, the cross wires in place of an object glass, and the vertical circle are very obvious, while the horizontal circle is so much end on that it can scarcely be recognized except by the tangent screw which is seen near the lower telephone. two such instruments are placed at the opposite extremities of a suitable base. the new base at upsala has a length of , feet; the old one was about half the length. the result of the change has been that the mean error of a single determination of the highest clouds has been reduced from to a little more than per cent. of the actual height. at the same time the difficulty of identifying a particular spot on a low cloud is considerably increased. a wire is laid between the two ends of the base, and each observer is provided with two telephones--one for speaking, the other for listening. when an observation is to be taken, the conversation goes on somewhat as follows: first observer, who takes the lead--"do you see a patch of cloud away down west?" "yes." "can you make out a well-marked point on the leading edge?" "yes." "well, then; now." at this signal both observers put down their telephones, which have hitherto engaged both their hands, begin to count fifteen seconds, and adjust their instruments to the point of cloud agreed on. at the fifteenth second they stop, read the various arcs, and the operation is complete. but when the angles have been measured the height has to be calculated, and also the horizontal and vertical velocities of the cloud by combining the position and height at two successive measurements at a short interval. there are already well-known trigonometrical formulæ for calculating all these elements, if all the observations are good; but at upsala they do far more. not only are the observations first controlled by forming an equation to express the condition that the two lines of sight from either end of the base should meet in a point, if the angles have been correctly measured and all bad sets rejected; but the mean errors of the rectangular co-ordinates are calculated by the method of least squares. [illustration: n. ekholm measuring clouds. this figure shows the peculiar ocular part of the altazimuth, with the vertical and horizontal circles. it also shows the telephonic arrangement.] the whole of the calculations are combined into a series of formulæ which are necessarily complicated, and even by using logarithms of addition and subtraction and one or two subsidiary tables--such as for log. sin²([theta]/ ) specially constructed for this work--the computation of each set of observations takes about twenty minutes. before we describe the principal results that have been attained, it may be well to compare this with the other methods which have been used to determine the height of clouds. a great deal of time and skill and money have been spent at kew in trying to perfect the photographic method of measuring the height of clouds. very elaborate cloud cameras, or photo-nephoscopes, have been constructed, by means of which photographs of a cloud were taken simultaneously from both ends of a suitable base. the altitude and azimuth of the center of the plate were read off by the graduated circles which were attached to the cameras; and the angular measurements of any point of cloud on the picture were calculated by proper measurements from the known center of the photographic plate. when all this is done, the result ought to be the same as if the altitude and azimuth of the point of the cloud had been taken directly by an ordinary angle measuring instrument. it might have been thought that there would be less chance of mistaking the point of the cloud to be measured, if you had the pictures from the two ends of the base to look at leisurely than if you could only converse through a telephone with the observer at the other end of the base. but in practice it is not so. no one who has not seen such cloud photographs can realize the difficulty of identifying any point of a low cloud when seen from two stations half a mile or a whole mile apart, and for other reasons, which we will give presently, the form of a cloud is not so well defined in a photograph as it is to the naked eye. at kew an extremely ingenious sort of projector has been devised, which gives graphically the required height of a cloud from two simultaneous photographs at opposite ends of the same base, but it is evident that this method is capable of none of the refinements which have been applied to the upsala measures, and that the rate of vertical ascent or descent of a cloud could hardly be determined by this method. but there is a far greater defect in the photographic method, which at present no skill can surmount. we saw that the altazimuth employed at upsala had no lenses. the meaning of this will be obvious to anyone who looks through an opera glass at a faint cloud. he will probably see nothing for want of contrast, and if anything of the nature of a telescope is employed, only well-defined cloud outlines can be seen at all. the same loss of light and contrast occurs with a photographic lens, and many clouds that can be seen in the sky are invisible on the ground glass of the camera. cirrus and cirro-stratus--the very clouds we want most to observe--are always thin and indefined as regards their form and contrast against the rest of the sky, so that this defect of the method is the more unfortunate. but even when the image of a cloud is visible on the focusing glass, it does not follow that any image will be seen in the picture. in practice, thin, high white clouds against a blue sky can rarely be taken at all, or only under exceptional circumstances of illumination. the reason seems to be that there is very little light reflected at all from a thin wisp of cirrus, and what there is must pass through an atmosphere always more or less charged with floating particles of ice or water, besides earthy dust of all kinds. the light which is scattered and diffused by all these small particles is also concentrated on the sensitive plate by the lens, and the resulting negative shows a uniform dark surface for the sky without any trace of the cloud. what image there might have been is buried in photographic fog. in order to compare the two methods of measuring clouds, i went out one day last december at upsala with messrs. ekholm and hagström when they were measuring the height of some clouds. it was a dull afternoon, a low foggy stratus was driving rapidly across the sky at a low level, and through the general misty gloom of a northern winter day we could just make out some striated stripes of strato-cirrus--low cirro-stratus--between the openings in the lower cloud layer. the camera and lens that i use habitually for photographing cloud forms--not their angular height--was planted a few feet from the altazimuth with which m. ekholm was observing, and while he was measuring the necessary angles i took a picture of the clouds. as might have been expected under the circumstances, the low dark cloud came out quite well, but there was not the faintest trace of the strato-cirrus on the negative. mm. ekholm and hagström, however, succeeded in measuring both layers of cloud, and found that the low stratus was floating at an altitude of about , feet high, while the upper strato-cirrus was driving from s. ° w. at an altitude of , feet, with a horizontal velocity of and a downward velocity of . feet per second. this is a remarkable result, and shows conclusively the superiority of the altazimuth to the photographic method of measuring the heights of clouds. whenever opportunity occurs, measures of clouds are taken three times a day at upsala, and it may be well to glance at the principal results that have been obtained. the greatest height of any cloud which has yet been satisfactorily measured is only , feet, which is rather less than has usually been supposed; but the highest velocity, miles an hour with a cloud at , feet, is greater than would have been expected. it may be interesting to note that the isobars when this high velocity was reported were nearly straight, and sloping toward the northwest. the most important result which has been obtained from all the numerous measures that have been made is the fact clouds are not distributed promiscuously at all heights in the air, but that they have, on the contrary, a most decided tendency to form at three definite levels. the mean summer level of these three stories of clouds at upsala has been found to be as follows: low clouds--stratus, cumulus, cumulo-nimbus, , - , feet; middle clouds--strato-cirrus and cumulo-cirrus, , - , feet; high clouds--cirrus, cirro-stratus, cirro-cumulus, , - , feet. it would be premature at present to speculate on the physical significance of this fact, but we find the same definite layers of clouds in the tropics as in these high latitudes, and no future cloud nomenclature or cloud observations will be satisfactory which do not take the idea of these levels into account. but the refinements of the methods employed allow the diurnal variations both of velocity and altitude to be successfully measured. the velocity observations confirm the results that have been obtained from mountain stations--that, though the general travel of the middle and higher clouds is much greater than that of the surface winds, the diurnal variation of speed at those levels is the reverse of what occurs near the ground. the greatest velocity on the earth's surface is usually about p.m.; whereas the lowest rate of the upper currents is about midday. the diurnal variation of height is remarkable, for they find at upsala that the mean height of all varieties of clouds rises in the course of the day, and is higher between and in the evening than either in the early morning or at midday. such are the principal results that have been obtained at upsala, and no doubt they surpass any previous work that has been done on the subject. but whenever we see good results it is worth while to pause a moment to consider the conditions under which the work has been developed, and the nature and nurture of the men by whom the research has been conducted. scientific research is a delicate plant, that is easily nipped in the bud, but which, under certain surroundings and in a suitable moral atmosphere, develops a vigorous growth. the meteorological institute of upsala is an offshoot of the astronomical observatory of the university; and a university, if properly directed, can develop research which promises no immediate reward in a manner that no other body can approach. if you want any quantity of a particular kind of calculation, or to carry on the routine of any existing work in an observatory, it is easy to go into the labor market and engage a sufficient number of accurate computers, either by time or piece work, or to find an assistant who will make observations with the regularity of clockwork. but original research requires not only special natural aptitudes and enthusiasm to begin with, but even then will not flourish unless developed by encouragement and the identification of the worker with his work. it is rarely, except in universities, that men can be found for the highest original research. for there only are young students encouraged to come forward and interest themselves in any work for which they seem to have special aptitude. now, this is the history of the upsala work. prof. hildebrandsson was attached as a young man to the meteorological department of the astronomical observatory, and when the study of stars and weather were separated, he obtained the second post in the new meteorological institute. from this his great abilities soon raised him to the directorship, which he now holds with so much credit to the university. m. ekholm, a much younger man, has been brought up in the same manner. first as a student he showed such aptitude for the work as to be engaged as assistant; and now, as the actual observation and reduction of the cloud work is done by him and m. hagström, the results are published under their names, so that they are thoroughly identified with the work. upsala is the center of the intellectual life of sweden, and there, rather than at stockholm, could men be found to carry out original research. it redounds to the credit of the university that it has so steadily supported prof. hildebrandsson, and that he in his turn has utilized the social and educational system by which he is surrounded to bring up assistants who can co-operate with him in a great work that brings credit both to himself, to themselves, and to the institute which they all represent. ralph abercromby. * * * * * [continued from supplement, no. , page .] [journal of the society of chemical industry.] notes of a recent visit to some of the petroleum-producing territories of the united states and canada. by boverton redwood, f.i.c., f.c.s. canadian petroleum. when i visited canada in - , the refining of petroleum was principally conducted in the city of london, ontario. at the present time petrolia, ontario, is the chief seat of the industry, and it was accordingly to this city that we made our way. here we were treated with the greatest kindness and hospitality by mr. john d. noble, vice-president of the petrolia crude oil and tanking co., and his brother, mr. r. d'oyley noble, and were enabled in the short time at our disposal to visit typical portions of the producing territory and some of the principal refineries. the development of the canadian petroleum industry may be said to date from , when a well dug for water was found to yield a considerable quantity of petroleum; but long previously, indeed from the time of the earliest settlements in the county of lamberton, in the western part of the province of ontario, petroleum was known to exist in canada. in productive flowing wells were drilled at oil springs, but these wells, which were comparatively shallow, quickly became exhausted, and the territory was deserted on the discovery in of oil at petrolia, seven miles to the northward, and about miles southwest of the outlet of lake huron. recently the oil springs wells have been drilled deeper, and are now producing , to , barrels (of american gallons) per month. petroleum has also been found at bothwell, miles from oil springs, but this district has ceased to yield. quite recently a new territory has been discovered at euphemia, miles from bothwell, where, at the time of our visit, there were four wells producing collectively barrels per day. this territory is by some regarded as part of the bothwell field. the present producing oil belt extends from petrolia in a northwesterly direction, to the township of sarnia, and in a southeasterly direction to oil springs, but in the latter direction there is a break of about four and a quarter miles, commencing at a point about two miles from petrolia. at oil springs there appears to be a pool about two miles square. the extension of the belt then continues in the same direction, with another break of about nine miles, to the new oil field of euphemia, the average width of the oil belt being about two miles. in all, about , wells are believed to have been drilled in the canadian oil fields, and of these about , are now producing, the average yield being about three quarters of a barrel per well per day. the aggregate production is probably about , barrels per annum, the greater part of which is obtained in the petrolia district, and the stocks were at the time of our visit stated to amount to from , to , barrels. in the canadian oil fields the drilling contractor usually employs his own derrick, engine, boiler, and tools, furnishes wood and water, cases the well, and fixes the pump; the well owner providing the casing and pump, and subsequently erecting the permanent derrick. the wells in the oil springs field were formerly from ft. to ft. in depth, but the oil stratum then worked became waterlogged, and the wells are now sunk to a depth of about ft., and are cased to a depth of about ft. to shut off the water. the contract price for drilling a - / in. hole to a depth of about ft. under the conditions mentioned is dols. (£ ), and the time occupied in drilling is usually about a week when the work is continued night and day. the wells in the petrolia field have a depth of ft., the contract price, including the cost of ft. of wooden conductor, being dols. (£ ), and the time occupied in drilling being from six to twelve days. pole tools are used in drilling, the poles being of white ash, ft. in length. the derrick is about ft. in height. an auger some ft. in length, and about a foot in diameter, is used to bore through the earth to the bed rock, the auger being rotated by horse power. the drilling tools commonly consist of a bit, ½ ft. in length by - / in. in diameter, weighing about lb.; a sinker bar, into which the bit is screwed, ft. in length by in. in diameter, weighing about , lb.; and the jars, inserted between the sinker bar and the poles about ft. in length, and weighing lb. the tools are suspended by a chain, which passes three times round the end of the walking beam and thence to the windlass, with ratchet wheel fixed on the walking beam, by means of which the tools are gradually lowered as the drilling proceeds. the cable is thus only employed in raising the tools from the well and lowering them into it. the sand pump or bailer is frequently as much as ft. in length, and is about in. in diameter. the casing ( - / in diameter) costs about cents ( s. ½d.) per foot, and the ¼ in. pump, with piping, costs from dols. (£ ) to dols. (£ ), according to the length of pipe required. an ordinary square frame derrick costs, with mud sill, from dols. (£ s.) to dols. (£ s.), and the walking beam about dols. (£ s.) in many cases, however, a three-pole derrick, which can be erected at an expense of about dols. (£ ), is employed. a barrel wooden tank costs, erected, dols. (£ ). the canadian torpedo. the wells are torpedoed on completion with from to quarts of nitroglycerine, at a cost of dols. ( s.) per quart. the torpedoes employed in the canadian oil field are much smaller than those used for a similar purpose in the united states, the tin shell being only ft. in length by in. in diameter. we were enabled to witness the operation of torpedoing a well, and the following particulars, based on notes taken at the time, may be of interest: the torpedo case, which was furnished with a tube or "anchor" at the lower end, ft. in length, was placed in the mouth of the well and suspended so that its upper end was level with the surface of the ground. eight quarts of nitroglycerine, which was in a tin can, was then poured into the torpedo case, and the torpedo was carefully lowered into the well, which contained at the time about ft. of water, until the end of the anchor rested on the bottom of the well. a traveling primer or "go-devil squib" was then prepared as follows: a tin cone, in. in length by in. in diameter at the open end, was partially filled with sand to give it the necessary weight. a piece of double tape fuse, ft. long, was inserted into a nobel's treble detonator, and over the detonator and a portion of the fuse a perforated tin tube or sheath was passed. this tube was then inserted through a hole in a strip of tin fixed across the mouth of the conical cup into the sand, so that the detonator was embedded. the sand was then saturated with nitroglycerine, the fuse lighted, and the primer dropped into the well. in about seconds there was a perceptible tremor of the ground, immediately followed by a slight sound of the explosion. after an interval of a second or two there was a gurgling noise, and a magnificent black fountain shot up twice as high as the derrick, upon which all the spectators ran for shelter from the impending shower of oil and water. the well not being a flowing one, the outrush was only of momentary duration, and within a few minutes the drillers were at work removing from the well, by means of the sand pump, the fragments of rock which had been detached by the explosion. on the table are specimens of this rock, which i obtained at the time. the maximum yield per well is ten barrels per day, and the minimum yield for which it is considered profitable to pump is a quarter of a barrel per day. the yield being in some cases so small, it is usual to pump a number of wells through the agency of one engine, the various pumps being connected with the motor by means of wooden rods. in one instance i saw as many as eighty wells being thus pumped from one center. the motive power was a h.p. engine, which communicated motion, similar to that of the balance wheel of a watch, to a large horizontal wheel. from this wheel six main rod lines radiated, the length of stroke of the main lines being in., and the rate of movement strokes per minute. some of the wells being pumped from this center were from one-half to three-quarters of a mile distant, and altogether about eight miles of rods were employed in the pumping of the eighty wells. the pipe line system in canada has not been fully developed, and accordingly the well owner has to convey his oil by road to the nearest receiving station. thus from the euphemia oil field the oil has to be "teamed" miles, to bothwell. for the conveyance of the oil by road a long and slightly conical wooden tank or barrel, resting horizontally on a wagon, is employed. these vessels hold from eight to ten barrels of oil. the petrolia crude oil and tanking company is the principal transporting and storing company. the storage charge is one cent (½d.) per barrel per month, and the delivery charge two cents per barrel. the petroleum produced in the oil springs field is stored separately from that obtained in the petrolia field. the storage takes place for the most part in large underground tanks excavated in the retentive clay. these remarkable tanks are often as much as ft. in diameter by ft. in depth, and hold from , to , barrels. in the construction of the tanks the alluvial soil, of which there is about ft. or ft. above the clay, is curbed with wood and thoroughly puddled with clay. on the completion of the excavation, the entire vertical surface is then lined with rings of pine wood, so that the upper part down to the solid clay is doubly lined. the bottom is not lined. the roof of the tank is of wood, covered with clay. the cost of such a tank is about cents ( d.) per barrel, or , dols. (£ ) for an , barrel tank, and the time occupied in making such a tank is about six weeks. the crude petroleum from the petrolia field usually has a specific gravity ranging from . to . , while the specific gravity of the petroleum from the oil springs field ranges from . to . . the oil occurs in the corniferous limestone, and buildings constructed of this stone frequently exude petroleum in hot weather. canadian crude petroleum is of a black color, and possesses a very disagreeable odor, due to the presence of sulphur compounds. these characteristics are shown by the samples on the table, for some of which i am indebted to mr. james kerr, secretary of the petrolia oil exchange. the stills used in the process of refining the crude oil are horizontal two-flued cylinders, ft. in length by ft. in diameter, provided with six in. vapor pipes. the charge is barrels, and the following is an outline of the method of working. assuming the still to be charged on monday morning, heating is commenced about a.m., and the naphtha begins to come over about a.m. of this product about six barrels is obtained in the case of petrolia crude, or ½ barrels in the case of oil springs crude. the distillation of the naphtha takes from to hours, say till : a.m. the heat is then increased, and the distillation of the kerosene commences about noon, and continues till about p.m. of the kerosene distillate about barrels are obtained. the first portion of the kerosene distillate is usually collected separately, is steamed to drive off the more volatile hydrocarbons, and is then mixed with the remainder of the kerosene distillate. the product which then commences to distill is known as tailings. this is collected separately and is redistilled. the distillation of the tailings continues till about a.m. on wednesday, by which time about barrels has been obtained. steam is then passed into the still through a perforated pipe extending to the bottom, and about barrels of "gas oil" is distilled over. the additional quantity of kerosene obtained on redistilling the tailings brings up the total yield of this product to about per cent. of the crude oil. the gas oil is sold for the manufacture of illuminating gas. the residue is distilled for lubricating oils and paraffin. the agitator in which the kerosene distillate is treated commonly takes a charge of barrels. to this quantity of distillate two carboys of oil of vitriol is added, and the oil and acid are agitated together for minutes. the tarry acid having been allowed to settle is drawn off, and seven carboys more of acid is added. agitation having been effected for or minutes, the tarry acid is removed as before. another similar treatment with seven carboys of acid follows, and occasionally a fourth addition of acid is made. the oil is next allowed to remain at rest for an hour, any acid which settles out being drawn off, and cold (or, in winter, slightly warmed) water is allowed to pass down through the oil in fine streams, this treatment being continued, without agitation of the oil, for half an hour, or until the dark color which the oil assumed on treatment with acid is removed. the water is then drawn off, barrels of solution of caustic soda (sp. gr. ° b.) is added, and agitation conducted for minutes. the caustic soda solution having been drawn off, barrels of a solution of litharge in caustic soda is added. this solution is made by dissolving caustic soda in water to a density of ° b. and then adding the litharge. agitation with this solution is continued for about six hours, or until the oil is thoroughly deodorized. about lb. of sublimed sulphur is then added, and the agitation is continued for another two hours. the oil having been allowed to settle all night, the litharge solution is drawn off, and the oil run into a shallow tank or "bleacher," where it is exposed to the light to improve its color, and is, if necessary, steamed to drive off the lighter hydrocarbons and raise the flashing point to the legal minimum of ° f. to raise the flashing point from ° f. to ° f. (abel test) is stated to involve in practice a loss of per cent., the burning quality of the oil being at the same time seriously impaired, and upon this ground the ontario refiners in petitioned for a reduction of the test standard. the average percentage yield of the various products is given in the following table: naphtha. kerosene. gas oil. tar. coke. loss (including water). --- there are a dozen petroleum refineries in canada, and the annual outturn of kerosene is about , barrels of imperial gallons per annum. the total consumption of kerosene in canada is about , barrels, one-third of which is manufactured in the united states. the united states oil is subject to a duty of cents on the package and - / cents per imperial gallon on the contents, besides which there is an inspection fee of cents per package. of lubricating oils the outturn is from , to , barrels per annum. the quality of canadian kerosene has been greatly improved of late years, but notwithstanding the elaborate process of refining, the oil, though thoroughly deodorized and of good color, contains sulphur, and of course evolves sulphur compounds in its combustion. the rules of the petrolia oil exchange provide that refined kerosene shall be of the odor "locally known as inoffensive," and shall "absolutely stand the test of oxide of lead in a strong solution of caustic soda without change of color." the "burning percentage" in the case of "extra refined oil," "water white" in color, and of specific gravity not exceeding . , is required to be not less than ; in the case of "no. refined oil," "prime white" in color, not less than ; and in the case of "no. refined oil," "standard white" in color, to be not less than . the "burning percentage" is determined by the use of a lamp thus described: "the bowl of the lamp is cylindrical, in. in diameter and ¾ in. deep, with a neck placed thereon of such a height that the top of the wick tube is in. above the bowl. a sun-hinge burner is used, taking a wick / in. wide and / in. thick, and a chimney about in. long." the test is conducted as follows: "the lamp bowl is filled with the oil and weighed, then lighted and turned up full flame just below the smoking point, and burned without interference till oz. of the oil is consumed. the quantity consumed during the first hour and the last hour is noted." the ratio of the two quantities is the measure of the burning quality, and the percentage that the latter quantity is of the former is the "burning percentage" referred to. * * * * * trees from a sanitary aspect. by charles roberts, f.r.c.s., etc. as this is the usual time of the year for planting, pruning, and removing forest trees and shrubs, it is a fit time for considering the influence which trees exert on the sanitary surroundings of dwelling places. the recent parliamentary report on forestry shows that trees are now of little commercial value in this country. and we may conclude, therefore, that they are chiefly grown for picturesque effect, and for the shelter from the sun and winds which they afford. the relation of forests to rainfall has been studied by meteorologists, but little attention has been given by medical climatologists to the share which trees take in determining local variations of climate and the sanitary condition of dwellings, notwithstanding they play as important a part as differences of soil, of which so much is said and written nowadays. this remark does not apply to large towns, where trees grow with difficulty and are comparatively few in number, and where they afford a grateful relief to the eye, shade from the sun, and to a very slight extent temper the too dry atmosphere, but to suburban and country districts, where it is the custom to bury houses in masses of foliage--a condition of things which is deemed the chief attraction, and often a necessary accompaniment, of country life. trees of all kinds exercise a cooling and moistening influence on the atmosphere and soil in which they grow. the extent of these conditions depends on the number of trees and whether they stand alone, in belts, or in forests; on their size, whether tall trees with branchless stems or thickets of underwood: on their species, whether deciduous or evergreen; and on the season of the year. the cooling of the air and soil is due to the evaporation of water by the leaves, which is chiefly drawn from the subsoil--not the surface--by the roots, and to the exclusion of the sun's rays from the ground, trees themselves being little susceptible of receiving and radiating heat. the moisture of the atmosphere and ground about trees is due to the collection by the leaves and branches of a considerable portion of the rainfall, the condensation of aqueous vapor by the leaves, and the obstruction offered by the foliage to evaporation from the ground beneath the trees. the experiments of m. fautrat show that the leafage of leaf bearing trees intercepts one-third, and that of pine trees the half, of the rainfall, which is afterward returned to the atmosphere by evaporation. on the other hand, these same leaves and branches restrain the evaporation of the water which reaches the ground, and that evaporation is nearly four times less under a mass of foliage in a forest, and two and one-third times under a mass of pines, than in the open. moreover, trees prevent the circulation of the air by lateral wind currents and produce stagnation. hence, as mr. e.j. symons has truly observed, "a lovely spot embowered in trees and embraced by hills is usually characterized by a damp, misty, cold, and stagnant atmosphere," a condition of climate which is obviously unfavorable to good health and especially favorable to the development of consumption and rheumatism, our two most prevalent diseases. now, if we examine the surroundings of many of our suburban villas and country houses of the better sort, we shall find them embowered in trees, and subject to all the insanitary climatic conditions just mentioned. the custom almost everywhere prevails of blocking out of view other houses, roads, etc., by belts of trees, often planted on raised mounds of earth, and surrounded by high close walls or palings, from a foolish ambition of seeming to live "quite in the country." this is a most unwise proceeding from a sanitary point of view, and should be protested against as strongly by medical men as defective drainage and bad water supply. many houses stand under the very drip and shadow of trees, and "the grounds" of others are inclosed by dense belts of trees and shrubs, which convert them into veritable reservoirs of damp, stagnant air, often loaded with the effluvia of decaying leaves and other garden refuse, a condition of atmosphere very injurious to health, and answerable for much of the neuralgia of a malarious kind, of which we have heard so much lately. a very slight belt of trees suffices to obstruct the lateral circulation of the air, and if the sun be also excluded the natural upward currents are also prevented. as far back as lancisi recognized the influence of slight belts of trees in preventing the spread of malaria in rome, and the cold, damp, stagnant air of spaces inclosed by trees is easily demonstrated by the wet and dry bulb thermometer, or even by the ordinary sensations of the body. a dry garden, on gravel, of three acres in extent in surrey, surrounded by trees, is generally three or four degrees colder than the open common beyond the trees; and a large pond in a pine wood twenty miles from london afforded skating for ninety consecutive days in the winter of - , while during the greater part of the time the lakes in the london parks were free from ice. the speculative builder has more sins to answer for than the faulty construction of houses. he generally begins his operations by cutting down all the fine old trees which occupy the ground, and which from their size and isolation are more beautiful than young ones and are little likely to be injurious to health, and ends them by raising mounds and sticking into them dense belts of quick-growing trees like poplars to hide as speedily as possible the desolation of bricks and mortar he has created. it is this senseless outdoor work of the builder and his nurseryman which stands most in need of revision from time to time in suburban residences, but which rarely receives it from a silly notion, amounting to tree worship, which prohibits the cutting down of trees, no matter how injudicious may have been the planting of them in the first instance from a sanitary or picturesque point of view. the following hints for planting and removing trees may be useful to those persons who have given little attention to the subject. a tree should not stand so near a house that, if it were to fall, it would fall on the house; or, in other words, the root should be as far from the house as the height of the tree. belts of trees may be planted on the north and east aspects of houses, but on the east side the trees should not be so near, nor so high, as to keep the morning sun from the bedroom windows in the shorter days of the year. on the south and west aspects of houses isolated trees only should be permitted, so that there may be free access of the sunshine and the west winds to the house and grounds. high walls and palings on these aspects are also objectionable, and should be replaced by fences, or better still open palings, especially about houses which are occupied during the fall of the leaf, and in the winter. trees for planting near houses should be chosen in the following order: conifers, birch, acacia, beech, oak, elm, lime, and poplar. pine trees are the best of all trees for this purpose, as they collect the greatest amount of rainfall and permit the freest evaporation from the ground, while their branchless stems offer the least resistance to the lateral circulation of the air. acacias, oaks, and birches are late to burst into leaf, and therefore allow the ground to be warmed by the sun's rays in the early spring. the elm, lime, and chestnut are the least desirable kinds of trees to plant near houses, although they are the most common. they come into leaf early and cast their leaves early, so that they exclude the spring sun and do not afford much shade in the hot autumn months, when it is most required. the lime and the elm are, however, beautiful trees, and will doubtless on this account often be tolerated nearer houses than is desirable from a purely sanitary point of view. trees are often useful guides to the selection of residences. numerous trees with rich foliage and a rank undergrowth of ferns or moss indicate a damp, stagnant atmosphere; while abundance of flowers and fruit imply a dry, sunny climate. children will be healthiest where most flowers grow, and old people will live longest where our common fruits ripen best, as these conditions of vegetation indicate a climate which is least favorable to bronchitis and rheumatism. pines and their companions, the birches, indicate a dry, rocky, sandy, or gravel soil; beeches, a dryish, chalky, or gravel soil; elms and limes, a rich and somewhat damp soil; oaks and ashes, a heavy clay soil; and poplars and willows, a low, damp, or marshy soil. many of these are found growing together, and it is only when one species predominates in number and vigor that it is truly characteristic of the soil and that portion of the atmosphere in connection with it. curzon street, mayfair, w.--_lancet._ * * * * * solidification by pressure. m. amagat has succeeded in solidifying various liquids, by compressing them in cylinders of bronze and steel. he has also photographed the crystals after crystallization, by means of a ray of electric light traversing the interior of the vessel by glass cones serving as panes. the stages of crystallization can be observed in this way with chloride of carbon, and it is seen that the process varies with the rapidity with which the pressure is produced. if rapidly, a sudden circlet of crystals gathers round the edge of the luminous field, and grows to the center. the pressure being continued, the field becomes obscure, then transparent. as the pressure is diminished the reverse takes place, and the liquid state is reproduced. m. amagat finds that chloride of carbon solidifies at . ° cent., under a pressure of atmospheres. at ° cent., benzine crystallizes with a pressure of about atmospheres. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . stitched in paper, or $ . bound in stiff covers. combined rates.--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway, new york, n. y. * * * * * patents. in connection with the scientific american, messrs. munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats, trade marks, their costs, and how procured. address munn & co., broadway, new york. branch office, and f st., washington, d.c. * * * * * the scientific american architects and builders edition. $ . a year. single copies, cts. this is a special edition of the scientific american, issued monthly--on the first day of the month. each number contains about forty large quarto pages, equal to about two hundred ordinary book pages, forming, practically, a large and splendid magazine of architecture, richly adorned with _elegant plates in colors_ and with fine engravings, illustrating the most interesting examples of modern architectural construction and allied subjects. a special feature is the presentation in each number of a variety of the latest and best plans for private residences, city and country, including those of very moderate cost as well as the more expensive. drawings in perspective and in color are given, together with full plans, specifications, costs, bills of estimate, and sheets of 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the fullness, richness, cheapness, and convenience of this work have won for it the largest circulation of any architectural publication in the world. munn & co., publishers, broadway, new york. a catalogue of valuable books on architecture, building, carpentry, masonry, heating, warming, lighting, ventilation, and all branches of industry pertaining to the art of building, is supplied free of charge, sent to any address. * * * * * building plans and specifications. in connection with the publication of the building edition of the scientific american, messrs. munn & co. furnish plans and specifications for buildings of every kind, including churches, schools, stores, dwellings, carriage houses, barns, etc. in this work they are assisted by able and experienced architects. full plans, details, and specifications for the various buildings illustrated in this paper can be supplied. those who contemplate building, or who wish to alter, improve, extend, or add to existing buildings, whether wings, porches, bay windows, or attic rooms, are invited to communicate with the undersigned. our work extends to all parts of the country. estimates, plans, and drawings promptly prepared. terms moderate. address munn & co., broadway, new york. proofreading team at www.pgdp.net [illustration] scientific american supplement no. new york, february , . scientific american supplement. vol. xxv., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents i. architecture.--elements of architectural design.--by h.h. statham.--the commencement of a series of lectures delivered before the london society of arts, giving the line of development of the different styles and the aspirations of their originators. illustrations. ii. astronomy.--a fivefold comet.--a curious astronomical deduction; the probable division of one comet into five by the disturbing effects of the sun. illustration. iii. biography.--linnæus.--by c.s. hallberg.--the life and work of the great botanist, his portrait and birthplace. illustrations. iv. chemistry.--an apparatus for preparing sulphurous, carbonic, and phosphoric anhydrides.--by h.n. warren.--a simple apparatus for this purpose described and illustrated. illustration. the arrangement of atoms in space in organic molecules.--a review of prof. johannes wislicenus' recent theories on this abstract subject. the isolation of fluorine.--note on this last isolation of an element, with the properties of the gas. illustration. v. electricity.--observations on atmospheric electricity.--by prof. l. weber.--abstract of a british association paper on this important subject. the menges thermo-magnetic generator and motor.--the direct conversion of electricity into heat; the generator fully described. illustrations. vi. engineering.--an investigation into the internal stresses occurring in cast iron and steel.--by general nicholas kalakoutzky.--first installment of an elaborate paper, giving theoretical and experimental examination of this subject. illustrations. hargreaves' thermo-motor.--a new caloric engine.--its construction, theory, and cylinder diagrams. illustrations. the compound steam turbine.--a description and discussion of this motor, in which a series of forty-five turbines are acted on by the current of steam. illustrations. vii. miscellaneous.--cold storage for potatoes.--the application of artificial cold to preserving potatoes.--results obtained in actual experience.--a practical paper by mr. edwin taylor. viii. physics.--on a method of making the wave length of sodium light the actual and practical standard of length.--by albert a. michelson and edward w. morley.--description of the new standard of length and outlines of the practical method for its determination.--the question of check determinations. illustration. ix. technology.--progress of the sorghum sugar industry.-- elaborate report on the diffusion process as developed at the fort worth, kan., station. illustrations. the lowe incandescent gas burner.--the well known advanced type of gas burner described and illustrated. illustration. * * * * * the compound steam turbine. last year the whole of the lighting of the newcastle exhibition was effected by the agency of seventeen of these motors, of which four were spare, giving in the aggregate electrical horse power. as the steam was provided by the authorities of the exhibition, it was good proof to the public that they had satisfied themselves that the consumption would not be extravagant, as however favorable might be the terms on which the manufacturers would be willing to lend their engines, they could scarcely be sufficiently tempting to compensate for an outrageous consumption of coal, even in newcastle. at the time we gave an account of the result of the test, showing that the steam used was lb. per electrical horse power, a very satisfactory result, and equal to lb. per indicated horse power if compared with an ordinary engine driving a generator through a belt. recently mr. parsons has given an account of the theory and construction of his motor before the northeast coast institution, and has quoted lb. of steam per electric horse power as the best result hitherto attained with a steam pressure of lb. as now made there are forty-five turbines through which the steam passes in succession, expanding in each, until it is finally exhausted. [illustration: the compound steam turbine.] the theoretical efficiency of a motor of this kind is arrived at by mr. parsons in the following manner: the efflux of steam flowing from a vessel at . lb. per square inch absolute pressure through an orifice into another vessel at lb. pressure absolute is ft. per second, the drop of pressure of . lb. corresponding to a diminution of volume of per cent. in the opposite direction. the whole turbines are so proportioned that each one, starting from the steam inlet, has per cent. more blade area or capacity than that preceding it. taking the pressure at the exhaust end to be lb. absolute, that at the inlet end will be lb. above the atmosphere. the steam enters from the steam pipe at lb. pressure, and in passing through the first turbine it falls . lb. in pressure, its velocity due to the fall being ft. per second, and its increase of volume . per cent. of its original volume. it then passes through the second turbine, losing . lb. in pressure, and gaining . per cent. in volume, and so on until it reaches the last turbine, when its pressure is . lb. before entering, and lb. on leaving. the velocity due to the last drop is ft. per second. the velocity of the wheels at , revolutions per minute is ft. per second, or . per cent. of the mean velocity due to the head throughout the turbines. comparing this velocity with the results of a series of experiments made by mr. james b. francis on a tremont turbine at lowell, mass., it appears that there should be an efficiency of per cent. if the blades be equally well shaped in the steam as in the water turbine, and that the clearances be kept small and the steam dry. further, as each turbine discharges without check into the next, the residual energy after leaving the blades is not lost as it is in the case of the water turbine, but continues into the next guide blades, and is wholly utilized there. this gain should be equal to to per cent. as each turbine of the set is assumed to give . per cent. efficiency, the total number may be assumed to give the same result, or, in other words, over per cent. of the power derived from using the steam in a perfect engine, without losses due to condensation, clearances, friction, and such like. a perfect engine working with lb. boiler pressure, and exhausting into the atmosphere, would consume . lb. of steam per hour for each horse power. a motor giving per cent. efficiency would, therefore, require . lb. of steam per horse power per hour. the best results hitherto attained have been lb. of steam per hour per electrical horse power, as stated above, but it is anticipated that higher results will be attained shortly. whether that be so or not, the motor has many advantages to recommend it, and among these is the increased life of the lamps due to the uniform rotation of the dynamo. at the phoenix mills, newcastle, an installation of edison-swan lamps has been running, on an average, eleven hours a day for two years past, yet in that time only lamps have failed, the remaining being in good condition after , hours' service. now, if the lamps had only lasted , hours on the average, as is commonly assumed, the renewals would have amounted to double the year's cost of fuel, as at present consumed. the present construction of the motor and dynamo is shown in the figures. [illustration: fig. though ] fig. shows the arrangement of complete turbines, lying on each side of the central steam inlet. the guide blades, r, are cut on the internal periphery of brass rings, which are afterward cut in halves and held in the top and bottom halves of the cylinder by feathers. the moving blades, s, are cut on the periphery of brass rings, which are afterward threaded and feathered on to the steel shaft, and retained there by the end rings, which form nuts screwed on to the spindle. the whole of this spindle with its rings rotate together in bearings, shown in enlarged section, fig. . steam entering at the pipe, o, flows all round the spindle and passes along right and left, first through the guide blades, r, by which it is thrown on to the moving blades, s, then back on to the next guide blades, and so on through the whole series on each hand, and escapes by the passages, p, at each end of the cylinder connected to the exhaust pipe at the back of cylinder. the bearings, fig. , consist of a brass bush, on which is threaded an arrangement of washers, each successive washer alternately fitting to the bush and the block, while being alternately / smaller than the block outside and / larger than the bush in the hole. one broad washer at the end holds the bearings central. these washers are pressed together by a spiral spring, n, and nut, and, by friction against each other, steady or damp any vibration in the spindle that may be set up by want of balance or other cause at the high rate of speed that is necessary for economical working. the bearings are oiled by a small screw propeller, i, attached to the shaft. the oil in the drain pipes, d and f, and the oil tank, d, lies at a lower level than the screw, but the suction of the fan, k, raises it up into the stand pipe, h, over and around the screw, which gripes it and circulates it along the pipes to the bearings. the course of the oil is as follows: the oil is forced by the propeller, i, and oils the bearing, a. the greater part passes along the pipe, e, to the end bearing, c; some after oiling the bearing, c, drains back by the pipe, f, to the reservoir, d; the remaining oil passes along through the armature spindle, oils the bearings, b, and drains into the reservoir, d, from which the oil is again drawn along the pipe, g, into the stand pipe, h, by the suction of the fan, k. the suction of the fan is also connected to the diaphragm, l, and forms, with it and the spring, m, the principal part of the governor which actuates the throttle valve, v. fig. is the electrical control governor, which will be further described in connection with the dynamo. it acts directly upon the controlling diaphragm, l, by admitting or closing a large access of air to it, and thus exercises a controlling influence upon it. the dynamo which forms the other portion of the electric generator, fig. , is coupled to the motor spindle by a square tube coupling fitted on to the square spindle ends. the armature is of the drum type. the body is built up of thin iron disks threaded on to the spindle and insulated from each other by tracing paper. this iron body is turned up and grooves milled out to receive the conducting wires. for pressures of to volts there are fifteen convolutions of wire, or grooves. the wire starting at b, fig. , is led a quarter of a turn spirally, c, round the cylindrical portion, a, then passing along a groove longitudinally is again led a quarter turn spirally, d, round the cylindrical portion, a, then through the end washer, and back similarly a quarter turn, e, then led along the diametrically opposite groove, and lastly a little over a quarter turn, f, back to g, where it is coupled to the next convolution. the commutator is formed of rings of sections. each section is formed of short lengths. each length is dovetailed and interlocked between conical steel rings. the whole is insulated with asbestos, and, when screwed up by the end nut, forms, with the steel bush, a compact whole. there are fifteen sections in the commutator, and each coupling is connected to a section. the whole armature is bound externally from end to end with brass or pianoforte steel wire. the magnets are of soft cast iron and of the horseshoe type. they are shunt-wound only. on the top of the magnet yoke is the electrical control governor, fig. . it consists of one moving spindle on which are keyed a small soft iron bar, and also a double finger, t. there is also a spiral spring, x, attached at one end to the spindle, and at the other to an adjustable top head and clamping nut, y. the double finger, t, covers or opens a small hole in the face, u, communicating by the pipe, w, to the diaphragm, l. the action of the magnet yoke is to attract the needle toward the poles of the magnet, while by turning the head the spiral spring, x, is brought into tension to resist and balance this force, and can be set and adjusted to any degree of tension. the double finger, t, turns with the needle, and, by more or less covering the small air inlet hole, u, it regulates the access of air to the regulating diaphragm, l. the second finger is for safety in case the brushes get thrown off, or the magnet circuit be broken, in which case the machine would otherwise gain a considerable increase of speed before the diaphragm would act. in these cases, however, the needle ceases to be attracted, falls back, and the safety finger closes the air inlet hole. there is no resistance to the free movement of this regulator. a fraction of a volt increase or decrease of potential produces a considerable movement of the finger, sufficient to govern the steam pressure, and in ordinary work it is found possible to maintain the potential within one volt of the standard at all loads within the capacity of the machine, excepting only a slight momentary variation when a large portion of the load is switched on or off. the resistance of the armature from brush to brush is only . ohm, the resistance of the field magnets is only . ohms, while the normal output of the dynamo is amperes at volts. this, excluding other losses, gives an efficiency of per cent. the other losses are due to eddy currents throughout the armature, magnetic retardation, and bearing friction. they have been carefully measured. by separately exciting the field magnets from another dynamo, and observing the increased steam pressure required to maintain the speed constant, the corresponding power was afterward calculated in watts. the commercial efficiency of this dynamo, after allowing for all losses, is a little over per cent. in the larger sizes it rises to per cent. assuming the compound steam turbine to give a return of per cent. of the total mechanical energy of the steam, and the dynamos to convert per cent of this into electrical output, gives a resulting efficiency of per cent. as steam at lb. pressure above the atmosphere will with a perfect non-condensing engine give a horse power for every . lb. of steam consumed per hour, it follows that an electrical generator of per cent. efficiency will consume . lb. of steam for every electrical horse power per hour. again, with steam at lb. pressure above the atmosphere, a generator of the same efficiency would consume only . lb. of steam per electrical horse power per hour. the results so far actually obtained are a consumption of lb. per hour of steam for each electrical horse power with a steam pressure of lb. above the atmosphere.--_engineering._ * * * * * hargreaves' thermo-motor. from the researches and investigations of carnot, joule, rankine, clausius, and sir william thomson, the science of thermo-dynamics has not only been brought into existence, but fully matured. we learn from it that whereas in the steam engine, on account of the limited range of temperature in the working cylinder and the rapid conduction of steam during condensation, no combination of cylinders can materially affect its present efficiency, internally fired engines, such as gas and caloric engines--being, as it were, less fettered--can have their already high efficiency increased by simply overcoming mechanical difficulties. to this fact is no doubt due the recent remarkable development of gas and caloric engines. the first caloric or hot air engine was invented by sir george cayley in , and in dr. robert stirling, a scotch minister, took out his first patent for a hot air engine, which was the foundation of many subsequent machines, and by the invention of the regenerator he converted what was practically a scientific toy into an efficient machine. one of the most ardent workers in this field at the present time is mr. james hargreaves, of widnes, who, with a thorough theoretical knowledge of the subject has, after many years of patient perseverance, over come many of the mechanical difficulties, and designed the engine of which the above is an illustration. the sectional elevation, shown in fig. , is an expanded view of the machine, shown thus to enable the action of the machine to be more clearly understood; the relative position of the different parts, as actually made, is shown in the side elevation (fig. ). the principal working parts of the machine are the combustion chamber, d, which is of the form shown, lined with fire brick, and having an entrance, with the door screwed down like a manhole lid; the working cylinder, a, surrounded by the water casing, k; the piston, b, with a water lining, and coupled to the end of the working beam by a parallel motion, the beam being supported by two rocking columns, z, as in engines of the "grasshopper" type; the air compressor, c, coupled directly to the piston of the working cylinder; the injection pump, f, for supplying the fuel--creosote or coal tar--to the combustion chamber; the regenerator e; the receiver and separator, v y; the feed and exhaust valves, m. [illustration: fig. --sectional elevation--hargreaves' thermo-motor.] [illustration: fig. .] the action of the machine is as follows: assuming the engine to be in condition for starting, the sides of the combustion chamber, d, are red hot, the chamber charged with air, and the spray of creosote, injected by the pump, f, is ignited; the expansion of the gases produced by the combustion acts upon the bottom of the piston, b, forcing it to the top of the cylinder, and thus, by intermediate mechanism, causing the crank shaft to revolve. by the same stroke a charge of air is forced by the compressor, c, into the receiver through the pipe, r. the cylinder is, of course, single acting, and on the down stroke of the piston, b--which falls by its own weight and the momentum of the fly wheel--the exhaust gases are forced through the regenerator, e, which absorbs most of their heat; they then pass through the exhaust valve, placed immediately under the feed valve, m, along the pipe, q, up through the pipes, t, fitted into the receiver, v, down the pipes, t, fitted into the saturator, y, and out of the funnel fixed to the bottom of y. [illustration: fig .] [illustration: fig. .] the charge of air for supplying the combustion chamber is forced by the compressor, c, through the pipe, r, _outside_ the tubes, t, in the chambers, v and y, along the pipe, p, through the feed valve, m, and the regenerator, e, into the combustion chamber. in its passage from the compressor, it first picks up the residual heat of the exhaust gases in the tubes, t, and finally the heat absorbed by the regenerator, e, thus entering the combustion chamber in a highly heated state. having described generally the passage of the air from the compressor to the working cylinder, and back again to the funnel, we will now describe the details. the working cylinder, a, is fitted into the casting which forms the water casing, k, a space being left between the bottom of the cylinder and the casing, which is filled with a non-conducting mixture of asbestos to protect it from the heat of combustion; the bottom of the piston, b, has a similar protection, and the regenerator has a lining of the same mixture, to prevent any heat from escaping through the casting which holds it. the water in the casing, k, and in the piston, b, is supplied by a small pump, g, which forces the water through the pipe, p , into the telescopic pipe, l either into the piston, b, or through the pipe, p , into the casing, k--the bottom of the casing being connected by the pipe, p , with the auxiliary boiler, w. the steam generated in the casing, k, is carried to the boiler, w, by the pipe, p , and from the boiler it passes along the pipe, p , through the valve, a , into the chamber, v, thus giving up its heat to the incoming air, with which it mixes. the vapor gradually condenses at the bottom of the vessel, y, and the water so formed is drawn by the pump, j, along the suction pipe, p , and forced through the pipe, p , back to the chamber, y, through the valve, a , and in the form of spray plays on the tubes, t, and absorbing any residual heat. the heat generated by compression in the cylinder, c, is absorbed by a spray of water from the pump, h, the vapor being carried along with the air through the pipe, r, to the chamber, y, where it is separated, and falling to the bottom is circulated, as just described, by the pump, j. x is a small auxiliary air compressor, to obtain the necessary compression to start the engine, and is worked from the boiler, w. in future engines this compressor will be superseded by a specially designed injector, which will produce the necessary pressure at a considerable reduction in cost. when once the engine is started, the fire of the auxiliary boiler can, of course, be drawn, as the main engine afterward makes its own steam. the regenerator, e, has circular ends of fire clay perforated, the body being filled with fire clay spirals of the shape clearly shown in elevation in fig. . the injector valve for the creosote is shown to a larger scale in fig. . this valve has, however, been since considerably modified and improved. the feed and exhaust valves, m, are actuated by cams keyed to a countershaft driven by bevel wheels from the main shaft. the creosote pump, f, is also worked by a cam on the same shaft, but the pumps, g h j, are worked by eccentrics. a stop valve, n, is fixed to the supply pipe, p, under which is place a back pressure valve to retain the pressure in the combustion chamber. the engine is regulated by an ordinary porter governor actuating the throttle valve, o. an engine, as described, has been constructed by messrs. adair & co., engineers, waterloo road, liverpool, and has been running most satisfactorily for several weeks, the results being clearly shown by the indicator diagrams (figs. and ). the results obtained by this motor are very remarkable, and are a long way in advance of any previous performance, as only a little over ½ lb. of fuel is used per i.h.p. per hour. it may be mentioned that the temperature of the combustion chamber is calculated to be about , °f., and that of the exhaust gases does not exceed °f.--_industries._ [illustration: diagram from cylinder-- in. diam, in. stroke. i.h.p., . scale, / in. mean pressure, . lb. fig. .] [illustration: diagram from air pump-- in. diam., in. stroke. i.h.p., . scale, / in--mean pressure, . lb. fig. . diagrams from cylinder and air pump. net indicated horse power, ; revolutions per minute, ; coal tar consumed per hour, . lb.; coal tar per i.h.p. per hour, . lb.] * * * * * an investigation into the internal stresses occurring in cast iron and steel. by general nicholas kalakoutzky. no. i. _determination of the influence of internal stresses on the strength of materials._--we call internal stresses those which exist within the mass of any hollow cylinder or other body, when it appears to be in a state of repose, or not under the influence of external forces. when pressure is applied to a hollow cylinder, either externally or internally, the interior layers into which its walls may be conceived to be divided are subjected to a new series of stresses, the magnitude of which is independent of those already existing. these additional stresses combine with the former in such a manner that at every point of the thickness of the cylinder they have common resultants acting in various directions. thus, if we call t the internal stress existing at a distance r_x from the axis of the cylinder, and in a direction tangential to its cross section, and t the additional stress due to pressure inside the cylinder acting at the same point and in the same direction, then the newly developed stress will be t + t. if r and r be the external and internal radii of the cylinder, and if we suppose the external pressure _nil_, then, if the pressure inside the bore be p , the stress on the radius r_x is determined by the following expression deduced from the well-known fundamental formulæ of lame:[ ] r ² r² + (r_x)² t = p ------- · ------------- r²-r ² (r_x)² from which we see that t is a maximum when r_x = r , i.e., for the layer immediately next to the bore of the cylinder. calling t the internal stress in this layer, and t the stress resulting from the action inside the bore of the pressure p , and allowing that the sum of both these quantities must not exceed the elastic limit u of the material, we have--t = u - t . and for this value of t , the corresponding pressure inside the bore will be r² - r ² p = (u - t ) ----------. r² + r ² this pressure increases with the term (u - t ). with t positive, i.e., when the internal stresses in the thickness of the hollow cylinder are such that the metal of the layers nearest to the bore is in a state of tension and that of the outer layers in a state of compression, then the cylinder will have the least strength when t has the greatest numerical value. such stresses are termed injurious or detrimental stresses. with t negative, the strength of the cylinder increases with the numerical value of t , and those stresses which cause compression in the layers nearest to the bore of the cylinder and tension in the outer layers are termed beneficial or useful stresses. [footnote : lame holds that in a homogeneous tube subjected to the action of two pressures, external and internal, the difference between the tension and the compression developed at any point of the thickness of the tube is a constant quantity, and that the sum of these two stresses is inversely proportional to the square of the radius of the layer under consideration. let r , r, and r_x be the respective radii, p , p¹, and p_x the corresponding pressures, and t , t¹, and t_x, the tensions, then we have: t - p = t_x - p_x ( ) (t + p ) r ² = (t_x + p_x) (r_x)² ( ) t_x - p_x = t¹ - p¹ ( ) (t_x + p_x)(r_x)² = (t¹ + p¹)r² ( ) if the radii are known and p and p¹ be given, then deducing from the above equations the values t and t¹, and also the variable pressure p_x, we determine-- p r ²(r² + (r_x)²) - p¹ r²((r_x)² + r ²) t_x = ------------------------------------------ (r² + r ²) (r_x)² this is the formula of lame, from which, making p¹ = , we obtain the expression in the text.] for these reasons, and in order to increase the power of resistance of a cylinder, it is necessary to obtain on the inner layer a state of initial compression approaching as nearly as possible to the elastic limit of the metal. this proposition is in reality no novelty, since it forms the basis of the theory of hooped guns, by means of which the useful initial stresses which should be imparted to the metal throughout the gun can be calculated, and the extent to which the gun is thereby strengthened determined. the stresses which arise in a hollow cylinder when it is formed of several layers forced on one upon another, with a definite amount of shrinkage, we call the stress of built-up cylinders, in order to distinguish them from natural stresses developed in homogeneous masses, and which vary in character according to the conditions of treatment which the metal has undergone. if we conceive a hollow cylinder made up of a great number of very thin layers--for instance, of wire wound on with a definite tension--in which case the inner layer would represent the bore of the gun, then the distribution of the internal stresses and their magnitude would very nearly approach the ideally perfect useful stresses which should exist in a homogeneous cylinder; but in hollow cylinders built up of two, three, and four layers of great thickness, there would be a considerable deviation from the conditions which should be aimed at. the magnitude of the stresses in built-up cylinders is determined by calculation, on the presumption that initial stresses do not exist in the respective layers of the tube and of the hoops which make up the walls of the cylinder. nevertheless, rodman, as early as the year , first drew attention to the fact that when metal is cast and then cooled, under certain conditions, internal stresses are necessarily developed; and these considerations led him, in the manufacture of cast iron guns, to cool the bore with water and to heat the outside of the moulds after casting. although rodman's method was adopted everywhere, yet up to the present time no experiments of importance have been made with the view of investigating the internal stresses which he had drawn attention to, and in the transition from cast iron to steel guns the question has been persistently shelved, and has only very lately attracted serious attention. with the aid of the accepted theory relating to the internal stresses in the metal of hooped guns, we can form a clear idea of the most advantageous character for them to assume both in homogeneous and in built-up hollow cylinders. in proof of this, we can adduce the labors of colonels pashkevitch and duchene, the former of whom published an account of his investigations in the _artillery journal_ for --st. petersburg--and the latter in a work entitled "basis of the theory of hooped guns," from which we borrow some of the following information. the maximum resistance of a tube or hollow cylinder to external stresses will be attained when all the layers are expanded simultaneously to the elastic limit of the material employed. in that case, observing the same notation as that already adopted, we have-- r - r p = t -------- ( ) r but since the initial internal stresses before firing, that is previous to the action of the pressure inside the bore, should not exceed the elastic limit,[ ] the value of r will depend upon this condition. [footnote : we must, however, remark that in a built-up hollow cylinder the compression of the metal at the surface of the bore may exceed the elastic limit. this cannot occur in the case of natural stresses.] in a hollow cylinder which in a state of rest is free from initial stresses, the fiber of which, under fire, will undergo the maximum extension, will be that nearest to the internal surface, and the amount of extension of all the remaining layers will decrease with the increase of the radius. this extension is thus represented-- (r )² (r_x)² + r² (t_x)¹ = p ------------ . ------------ r² - (r )² (r_x)² therefore, to obtain the maximum resistance in the cylinder, the value t_x of the initial stress will be determined by the difference (t - t'_x),[*need to check the prime with library or work out the equations] and since p is given by equation ( ), then / r (r_x)² + r² \ t_x = t ( - ---------- · ------------- ) ( ) \ r + r (r_x)² / the greatest value t_x = t corresponds to the surface of the bore and must be t = -t, therefore r ² + r² --------------- = r (r + r ) whence p = t sqrt( ) = . t. from the whole of the preceding, it follows that in a homogeneous cylinder under fire we can only attain simultaneous expansion of all the layers when certain relations between the radii obtain, and on the assumption that the maximum pressure admissible in the bore does not exceed . u. equation ( ) may be written thus-- r r_x - rr t_x = t -------- . ---------- ( ) r + r (r_x)² substituting successively r_x = r and r_x = r, we obtain expressions for the stresses on the external and internal radii-- r - r r r - r t_r = t -------- and t_r = -t ---- -------- r + r r r + r therefore, in a homogeneous hollow cylinder, in which the internal stresses are theoretically most advantageous, the layer situated next to the bore must be in a state of compression, and the amount of compression relative to the tension in the external layer is measured by the inverse ratio of the radii of these layers. it is further evident that the internal stresses will obey a definite but very simple law, namely, there will be in the hollow cylinder a layer whose radius is sqrt(r r ), in which the stress is _nil_; from this layer the stresses increase toward the external and the internal radii of the cylinder, where they attain a maximum, being in compression in the internal layers and in tension in the external ones. the internal pressures corresponding to these stresses may be found by means of very simple calculations. the expression for this purpose, reduced to its most convenient form, is as follows: r / r \ / r \ p_x = t -------- ( --- - ) ( - ----- ) ( ) r + r \ r_x / \ r_x / in order to represent more clearly the distribution of stresses and pressures in the metal of a homogeneous ideally perfect hollow cylinder, let us take, as an example, the barrel of a in. gun-- mm. let us suppose t = , atmospheres; therefore, under the most favorable conditions, p = . t, or , atmospheres. from equation ( ) we determine r = . mm. with these data were calculated the internal stresses and the pressures from which the curve represented in fig. is constructed. the stresses developed under fire with a pressure in the bore of , atmospheres are represented by a line parallel to the axis of the abscissæ, since their value is the same throughout all the layers of metal and equal to the elastic limit, , atmospheres. if, previous to firing, the metal of the tube were free from any internal stresses, then the resistance of the tube would be r² - r²_ p = u ----------- , r² + r²_ or , atmospheres--that is, one-half that in the ideally perfect cylinder. from this we perceive the great advantage of developing useful initial stresses in the metal and of regulating the conditions of manufacture accordingly. unless due attention be paid to such precautions, and injurious stresses be permitted to develop themselves in the metal, then the resistance of the cylinder will always be less than , atmospheres; besides which, when the initial stresses exceed a certain intensity, the elastic limit will be exceeded, even without the action of external pressures, so that the bore of the gun will not be in a condition to withstand any pressure because the tensile stress due to such pressure, and which acts tangentially to the circumference, will increase the stress, already excessive, in the layers of the cylinder; and this will occur, notwithstanding the circumstance that the metal, according to the indications of test pieces taken from the bore, possessed the high elastic limit of , atmospheres. [illustration: fig. ] in order to understand more thoroughly the difference of the law of distribution of useful internal stresses as applied to homogeneous or to built-up cylinders, let us imagine the latter having the external and internal radii of the same length as in the first case, but as being composed of two layers--that is to say, made up of a tube with one hoop shrunk on under the most favorable conditions--when the internal radius of the hoop = sqrt(r v ) or . mm., fig. , has been traced, after calculating, by means of the usual well known formulæ, the amount of pressure exerted by the hoop on the tube, as well as the stresses and pressures inside the tube and the hoop, before and after firing. a comparison of these curves with those on fig. will show the difference between the internal stresses in a homogeneous and in a built-up cylinder. in the case of the hooped gun, the stresses in the layers before firing, both in the tube and in the hoop, diminish in intensity from the inside of the bore outward; but this decrease is comparatively small. in the first place, the layer in which the stresses are = when the gun is in a state of rest does not exist. secondly, under the pressure produced by the discharge, all the layers do not acquire simultaneously a strain equal to the elastic limit. only two of them, situated on the internal radii of the tube and hoop, reach such a stress; whence it follows that a cylinder so constructed possesses less resistance than one which is homogeneous and at the same time endowed with ideally perfect useful initial stresses. the work done by the forces acting on a homogeneous cylinder is represented by the area _a b c d_, and in a built-up cylinder by the two areas _a' b' c' d'_ and _a" b" c" d"_. calculation shows also that the resistance of the built-up cylinder is only , atmospheres, or per cent. of the resistance of a homogeneous cylinder. by increasing the number of layers or rows of hoops shrunk on, while the total thickness of metal and the caliber of the gun remains the same, we also increase the number of layers participating equally in the total resistance to the pressure in the bore, and taking up strains which are not only equal throughout, but are also the greatest possible. we see an endeavor to realize this idea in the systems advocated by longridge, schultz, and others, either by enveloping the inner tubes in numerous coils of wire, or, as in the later imitations of this system, by constructing guns with a greater number of thin hoops shrunk on in the customary manner. but in wire guns, as well as in those with a larger number of hoops--from four to six rows and more--the increase in strength anticipated is acknowledged to be obtained in spite of a departure from one of the fundamental principles of the theory of hooping, since in the majority of guns of this type the initial compression of the metal at the surface of the bore exceeds its elastic limit.[ ] we have these examples of departure from first principles, coupled with the assumption that initial stresses do not exist in any form in the metal of the inner tube previous to the hoops having been shrunk on; but if the tube happen to be under the influence of the most advantageous initial stresses, and we proceed either to hoop it or to envelope it with wire, according to the principles at present in vogue, then, without doubt, we shall injure the metal of the tube; its powers of resistance will be diminished instead of increased, because the metal at the surface of the bore would be compressed to an amount exceeding twice its elastic limit. an example of injury inflicted in this way is to be found in the method adopted for hooping cast iron tubes cast by rodman's process. if we take into consideration the undoubted fact of the existence to a considerable extent of useful initial stresses in these tubes, then the hoops should be put on them either with very little shrinkage or none at all, whereas ordnance authorities everywhere have applied to this case methods which are only correct for tubes which are free from initial stresses. [footnote : in certain cases this, of course, may be an advantage, as, for instance, when the inner tube is under injurious initial stresses; but then, in order to be able to apply the necessary shrinkage, we must know the magnitude of these stresses.] [illustration: fig. ] during the process of hooping guns it is very important to know how to take into account the value and mode of distribution of the prejudicial stresses in the inner tube, should such exist. knowing these stresses, it is possible, by regulating the tension of the hoops, to reduce the compression of the metal at the surface of the bore to the proper extent, thus doing away with the previously existing tension, and by that means removing a source of weakness in the tube. in precisely the same way in the shrinkage of gun hoops attention must be paid to the character and value of the stresses which arise in the course of their manufacture; otherwise it will be impossible to hoop the barrel throughout in a proper manner. if prejudicial stresses exist in the metal of a hoop before it is put in its place, then, when the gun is fired, if it had been shrunk on with the degree of tension usually allowed, the layer situated in the internal radius will be extended beyond admissible limits, thereby causing the resistance of the gun to be less than that prescribed.[ ] [footnote : when the inner tube is strengthened by means of wire, the initial or natural stresses in the latter may be neglected on account of its thinness; but when the thickness of the hoops is reduced, and the number of layers thereby increased, then the value of the initial stresses in these hoops is a very important factor with respect to the decrease or increase of the powers of resistance of the gun.] it is evident, from what has been said, that in order to determine precisely the resistance of hollow cylinders to internal pressures, and to make the correct calculations for hooping tubes, it is absolutely necessary to know whether internal initial stresses exist in the tube and in the hoops, and to ascertain what their nature and intensity may be--that is to say, whether they are useful or detrimental; yet it is incontestable that in the construction of modern ordnance no attention has been paid to the investigations indicated. if it be possible to ignore these considerations in the manufacture of guns of small caliber, and where the thickness of metal is not sufficiently great to admit of strongly developed internal stresses, such is by no means the case with the colossal and costly weapons of the present day. in these the thickness of metal in the tube and hoops is very great; hence the extreme probability of very considerable internal stresses developing themselves. that the strength of large guns is often far below that anticipated is demonstrated, year by year, by the repeated cases of failure. consciousness as to the want of strength in such guns is made evident by the precautionary measures as to their use everywhere adopted. the heavy artillery produced in the gun factories of europe is constructed with all the skill, science, and experience which engineers and artillerists can command, and therefore it would seem that instances of defective strength should not arise. such cases, however, do occur everywhere, and irresistibly give rise to the suspicion that not only is the system of construction of guns of large caliber faulty, but also that the conditions of their manufacture must be considered as defective. bearing in mind the enormous sums of money expended by every nation in order to secure an armament of completely trustworthy guns, this question demands speedy and searching investigation. the first step in this direction is the study of the internal stresses inherent in the metal; because, if such exist, and are capable of attaining, under certain conditions, considerable magnitudes, then it is absolutely necessary to take advantage of them in order to increase the resistance of the metal, instead of allowing them to act to its detriment. the study of natural internal stresses is of importance, not only with reference to gun making, but also in respect of other structures where great resistance is required. all have heard of the sudden failure of crank shafts and piston rods, of the bursting of boiler shells and tubes, of the breaking of tires, etc. in the majority of cases the investigations into the causes of such sudden failures have not led to any definite results. it has usually been found that the metal possessed a satisfactory elastic resistance, and satisfied all the conditions set down in the specifications. had attention been paid during these investigations to the state of the internal stresses in the metal, the cause of unlooked-for accidents might have been explained, and steps would consequently have been taken to avoid them in future. we are also familiar with the development of considerable internal stresses in various kinds of steel articles which are subjected to hardening and tempering; for example, as dies, tools of various description, sword blades, and thin plates rolled at a low temperature or subjected to cold hammering. in the foundry the appearance of internal stresses is of still more frequent occurrence. the neglect of certain practical rules in casting, and during the subsequent cooling, leads to the spontaneous breakage of castings after a few hours or days, although taken out of the sand apparently perfectly sound. projectiles for penetrating armor plate, and made of cast steel, as well as shells which have been forged and hardened, and in which the metal possessed an ultimate resistance of over twelve thousand ( , ) atmospheres, with an elastic limit of more than six or seven thousand atmospheres, will crack to a serious extent, and even break up in the lathe, while the recess for the copper ring is being turned out. in shell of this nature, as well as in chilled cast iron shell, the heads are apt to fly off spontaneously either while they are lying in store or during transport. such phenomena, it seems to me, demonstrate the existence of internal stresses of considerable magnitude in the metal of the projectiles, and it is highly probable that the manufacture of many articles would have approached nearer to perfection had more attention been bestowed upon the study of the internal stresses which they were liable to. having thus explained the nature and importance of the subject, i will proceed to describe the experiments which i have made with a view to its illustration.--_london engineer._ * * * * * elements of architectural design.[ ] [footnote : delivered before the society of arts, london, november , . from the _journal_ of the society.] by h.h. statham. lecture i. judging from the nature of the correspondence on architecture and the duty of architects which is frequently seen in the columns of the daily papers, the _times_ especially, it would seem that the popular notion of architecture now is that it is a study mainly of things connected with sanitary engineering--of the best forms of drain pipes and intercepting traps. this is indeed a very important part of sound building, and it is one that has been very much neglected, and has been, in fact, in a comparatively primitive state until very recent times; and therefore it is not surprising that there should be a reaction in regard to it, and that newspapers which follow every movement of public opinion, and try to keep pace with it, should speak as if the drain pipe were the true foundation of architecture. i have a great respect for the drain pipe, and wish to see it as well laid and "intercepted" as possible; but i think, for all that, that there is something in architecture higher than sanitary engineering. i wish to consider it in these lectures as what i think it essentially is, what it has evidently been in the eyes of all those of past days who have produced what we now regard as great architectural monuments, namely, as an intellectual art, the object of which is to so treat the buildings which we are obliged to raise for shelter and convenience as to render them objects of interest and beauty, and not mere utilitarian floors, walls, and roofs to shelter a race who care nothing for beauty, and who only want to have their physical comfort provided for. architecture, then, from the point of view from which i am asking you to regard it--and the only point of view in which it is worth the serious regard of thoughtful people--is the art of erecting expressive and beautiful buildings. i say expressive _and_ beautiful, and i put expressive first, because it is the characteristic which we can at least realize even when we cannot realize what can fairly be called beauty, and it is the characteristic which comes first in the order of things. a building may be expressive and thereby have interest, without rising into beauty; but it can never be, architecturally speaking, beautiful unless it has expression. and what do we mean by expression in a building? that brings us to the very pith of the matter. we know pretty well what we mean when we say that a painted or sculptured figure is expressive. we mean that, while correctly representing the structure of the human figure, it also conveys to our minds a distinct idea of a special emotion or sentiment, such as human beings are capable of feeling and expressing by looks and actions. expression in this sense a building cannot be said to have. it is incapable of emotion, and it has no mobility of surface or feature. yet i think we shall see that it is capable of expression in more senses than one. it may, in the first place, express or reflect the emotion of those who designed it, or it may express the facts of its own internal structure and arrangement. the former, however, can only, i think, be said to be realized in the case of architecture of the highest class, and when taken collectively as a typical style. for instance, we can all pretty well agree that the mediæval cathedral expresses an emotion of aspiration on the part of its builders. the age that built the cathedrals longed to soar in some way, and this was the way then open to it, and it sent up its soul in spreading vaults, and in pinnacles and spires. so also we can never look at greek architecture without seeing in it the reflection of a nature refined, precise, and critical; loving grace and finish, but content to live with the graces and the muses without any aspirations that spurned this earth. we can hardly go further than this in attributing emotional expression to architecture. but in a more restricted sense of the word _expression_, a building may express very definitely its main constructive facts, its plan and arrangement, to a certain extent even its purpose, so far at least that we may be able to identify the class of structure to which it belongs. it not only may, but it ought to do this, unless the architecture is to be a mere ornamental screen for concealing the prosaic facts of the structure. there is a good deal of architecture in the world which is in fact of this kind--an ornamental screen unconnected with the constructional arrangement of the building. nor is such architecture to be entirely scouted. it may be a very charming piece of scenery in itself, and you may even make a very good theoretical defense for it, from a certain point of view. but on the whole, architecture on that principle becomes uninteresting. you very soon tire of it. it is a mask rather than a countenance, and tends to the production of a dull uniformity of conventional design. for we must remember that architecture, although a form of artistic expression, is not, like painting and sculpture, unfettered by practical considerations. it is an art inextricably bound up with structural conditions and practical requirements. a building is erected first for convenience and shelter; secondly only for appearance, except in the case of such works as monuments, triumphal arches, etc., which represent architectural effect pure and simple, uncontrolled by practical requirements. with such exceptions, therefore, a building ought to express in its external design its internal planning and arrangement; in other words, the architectural design should arise out of the plan and disposition of the interior, or be carried on concurrently with it, not designed as a separate problem. then a design is dependent on structural conditions also, and if these are not observed, the building does not stand, and hence it is obvious that the architectural design must express these structural conditions. it must not appear to stand or be constructed in a way in which it could not stand (like the modern shops which are supposed to stand on sheets of plate glass), and its whole exterior appearance ought to be in accordance with, and convey the idea of, the manner and principle on which it is constructed. the most important portions of the interior must be shown as such externally by the greater elaboration and emphasis of their architectural treatment. if the general arrangement of the plan is symmetrical, on either side of a center (which, however, it cannot often be except in the largest type of monumental or public buildings), the architectural treatment must be symmetrical. if the building is necessarily arranged, in accordance with the requirements of the plan, unsymmetrically, the architectural treatment must follow suit, and the same principle must be carried out through all the details. now this dependence of architectural design upon plan and construction is one of the conditions which is often overlooked by amateurs in forming a judgment upon architectural design; and the overlooking of this is one reason of the uncertainty of opinion about architecture as compared with such arts as sculpture and painting. few people know or care much about the structure and planning of buildings except those whose business it is to care about this; and consequently they do not realize what it is which they should look for in the architectural design. they like it or do not like it, and they regard this as what is called a mere question of taste, which, according to the proverb, is not to be disputed about. in fact, however, the good or bad taste of an architectural design, say, if you like, its correctness or incorrectness, is to a considerable extent a matter of logical reasoning, of which you must accurately know the premises before you can form a just conclusion. but there is another reason for this prevalent uncertainty and vagueness of opinion, arising out of the very nature of architectural art itself, as compared with the imitative arts. a painting of a figure on a landscape is primarily a direct imitation of the physical facts of nature. i do not for a moment say it is only that, for there is far more involved in painting than the imitation of nature; but the immediate reference to nature does give a standard of comparison which to a certain extent every eye can appreciate. but architecture is not an art which imitates natural forms at all, except as minor decorations, and it then does so, or should do so, only in a conventionalized manner, for reasons which we shall consider later on. architecture is, like music, a metaphysical art. it deals with the abstract qualities of proportion, balance of form, and direction of line, but without any imitation of the concrete facts of nature. the comparison between architecture and music is an exercise of the fancy which may indeed be pushed too far, but there is really a definite similarity between them which it is useful to notice. for instance, the regular rhythm, or succession of accentuated points in equal times, which plays so important a part in musical form, is discernible in architecture as a rhythm in space. we may treat a cottage type of design, no doubt, with a playful irregularity, especially if this follows and is suggested by an irregularity, of plan. but in architecture on a grand scale, whether it be in a greek colonnade or a gothic arcade, we cannot tolerate irregularity of spacing except where some constructive necessity affords an obvious and higher reason for it. then, again, we find the unwritten law running throughout all architecture that a progress of line in one direction requires to be stopped in a marked and distinct manner when it has run its course, and we find a similarly felt necessity in regard to musical form. the repetition so common at the close of a piece of music of the same chord several times in succession is exactly analogous to the repetition of cross lines at the necking of a doric column to stop the vertical lines of the fluting, or to the strongly marked horizontal lines of a cornice which form the termination of the height or upward progress of an architectural design. the analogy is here very close. a less close analogy may also be felt between an architectural and a musical composition regarded as a whole. a fugue of bach's is really a built-up structure of tones (as browning has so finely put it in his poem, "abt vogler"), in accordance with certain ideas of relation and proportion, just as a temple or a cathedral is a built-up structure of lines and spaces in accordance with ideas of relation and proportion. both appeal to the same sense of proportion and construction in the brain; the one through the ear, the other through the eye. then, in regard to architecture again, we have further limiting conditions arising not only out of the principle of construction employed, but out of the physical properties of the very material we employ. a treatment that is suitable and expressive for a stone construction is quite unsuitable for a timber construction. details which are effective and permanent in marble are ineffective and perishable in stone, and so; on and the outcome of all this is that all architectural design has to be judged, not by any easy and ready reference to exterior physical nature, with which it has nothing to do, but by a process of logical reasoning as to the relation of the design to the practical conditions, first, which are its basis, and as to the relation of the parts to each other. of course beyond all this there is in architecture, as in music, something which defies analysis, which appeals to our sense of delight we know not how or why, and probably we do not want to know; the charm might be dissolved if we did. but up to this point architectural design and expression are based on reasoning from certain premises. the design is good or bad as it recognizes or ignores the logic of the case, and the criticism of it must rest on a similar basis. it is a matter of thought in both cases, and without thought it can neither be designed nor appreciated to any purpose, and this is the leading idea which i wish to urge and to illustrate in these lectures. you may say: may not a design satisfy all these logical conditions, and yet be cold and uninteresting, and give one no pleasure? certainly it may. indeed, we referred just now to that last element of beauty which is beyond analysis. but, if we cannot analyze the result, i rather think we can express what it is which the designer must evince, beyond clear reasoning, to give the highest interest to his architecture. he must have taken an interest in it himself. that seems a little thing to say, but much lies in it. as matthew arnold has said of poetry: "what poets feel not, when they make a pleasure in creating, the world, in its turn, will not take pleasure in contemplating." the truth runs through all art. there are, alas, so many people who do not seem to have the faculty of taking pleasure, and there is so much architecture about our streets which it is impossible to suppose any one took "pleasure in creating." when a feature is put into a design, not because the designer liked it, but because it is the usual thing and it saves trouble, it always proclaims that melancholy truth. but where something is designed because the designer liked doing it, and was trying to please his own fancy instead of copying what a hundred other men have done before, it will go hard but he will give some pleasure to the spectator. it is from this blessed faculty that a design becomes inspired with what is best described as "character." it is not the same thing as style. i have something to say in my next lecture as to what i think _style_ means, but it is certain that a building may have _style_ and yet want _character_, and it may have a good deal of _character_ and yet be faulty or contradictory in _style_. we cannot define "character," but when we feel that it is present we may rely upon it that it is because the designer took interest and pleasure in his work, was not doing it merely scholastically--in short, he put something of his own character into it, which means that he had some to put. [illustration: figs. through ] now, coming back to the axiom before mentioned, that architectural design should express and emphasize the practical requirements and physical conditions of the building, let us look a little more in detail into the manner in which this may be done. we will take, to begin with, the very simplest structure we can possibly build--a plain wall (fig. ).[ ] here there is no expression at all; only stones piled one on another, with sufficient care in coursing and jointing to give stability to the structure. it is better for the wall, constructively, however, that it should have a wider base, to give it more solidity of foundation, and that the coping should project beyond the face of the wall, in order to throw the rain off, and these two requirements may be treated so as to give architectural expression to our work (fig. ). it now consists of three distinct portions--a plinth, or base, a superficies of wall, and a coping. we will mark the thickening at the base by a moulding, which will give a few horizontal lines (at b), and the coping in the same way. the moulding of the coping must also be so designed as to have a hollow throating, which will act as a drip, to keep the rain from running round the under side of the coping and down the wall. we may then break up the superficies by inserting a band of single ornament in one course of this portion of the wall--not half way, for to divide any portion of a building into mere "halves" has usually a weak and monotonous effect, but about two thirds of the distance from the base line; and this band of ornament not only breaks up the plain surface a little, but also, by carrying another horizontal line along the wall, emphasizes its horizontality. always emphasize that which is the essential characteristic of your structure. a wall of this kind is essentially a long horizontal boundary. emphasize its length and horizontality. [footnote : the dark shaded portion in this and the next two diagrams show the "section" of the wall as seen if we cut it through and look at it endwise.] if we are millionaires, and can afford to spend a great deal on a wall, we may not only (fig. ) carry further the treatment of the coping and base, by giving them ornamental adjuncts as well as mouldings, but we might treat the whole wall superficies as a space for surface carving, not mechanically repeated, but with continual variation of every portion, so as to render our wall a matter of interest and beauty while retaining all its usefulness as a boundary, observing that such surface ornament should be designed so as to fulfill a double object: , to give general relief to the surface of the wall; , to afford matter of interest to the eye on close inspection and in detail. that is the double function of nearly all architectural ornament. it is, in the first place, to aid the general expression and balance of the building, and give point and emphasis where needed; and, in the second place, to furnish something to the eye for study on its own account when viewed more closely. [illustration: figs. through ] we will take another typical and simple erection, a stone pillar to support the ends of two lintels or beams. this may be simply a long squared piece set on end (fig. ), and will perform its constructive functions perfectly well in that form; but it is not only absolutely expressionless, but is in one sense clumsy and inconvenient, as taking up more space than need be, presenting an unwieldy-looking mass when viewed at an angle, and shutting out a good deal of light (if that happen to be a matter of practical consequence in the case). cutting off the angles (fig. ) does not weaken it much, and renders it much less unwieldy-looking, besides giving it a certain degree of verticality of expression, and rendering it more convenient as taking up less room and obstructing less light. but though the column is quite strong enough, the octagonal top does not make so good a seat or bearing for the ends of the lintels. we will therefore put a flat square stone on the top of it (fig. ), which will serve as a bed for the lintels to rest on securely. but the angles of this bed plate, where they project beyond the face of the column, appear rather weak, and are so actually to some extent--a double defect, for it is not enough in architecture that a thing should be strong enough, it is necessary that it should appear so, architecture having to do with expression as well as with fact. we will, therefore, strengthen this projecting angle, and correct the abruptness of transition between the column and the bed plate, by brackets (fig. ) projecting from the alternate faces of the column to the angles of the bed plates. as this rather emphasizes four planes of the octagon column at the expense of the other four, we will bind the whole together just under the brackets by a thin band of ornament constituting a necking, and thus we have something like a capital developed, a definitely designed finish to our column, expressive of its purpose. this treatment of the upper end, however, would make the lower end rising abruptly from the ground seem very bare. we will accordingly emphasize the base of the column, just as we emphasized the base of the wall, by a projecting moulding, not only giving expression to this connection of the column with the ground, but also giving it the appearance, and to some extent the reality, of greater stability, by giving it a wider and more spreading base to rest on. we have here still left the lines of one column vertically parallel, and there is no constructive reason why they should not remain so. there is, however, a general impression to the eye both of greater stability and more grace arising from a slight diminution upward. it is difficult to account for this on any metaphysical principle, but the fact has been felt by most nations which have used a columnar architecture, and we will accept it and diminute (so to speak) our column (fig. ). we have here taken a further step by treating the shaft of the column in two heights, keeping the lower portion octagonal and reducing the upper portion to a circle, and we now find it easier to treat the capital so as to have a direct and complete connection with the column, the capital being here merely a spreading out of the column into a bracket form all round, running it into the square of the bed plate.[ ] the spreading portion is emphasized by surface ornament, and the necking is again emphasized, this time more decisively, by a moulding, forming a series of parallel rings round the column. if we wish to give our column an expression of more grace and elegance, we can further reduce the thickness of it (fig. ), and give more spread to the capital, always taking care to be sure that the strength of the column is not reduced below what the weight which it has to carry requires. in this case a bracket is shown above the capital, projecting longitudinally only (in the direction of the lintel bearing), a method of giving a larger bearing surface for the ends of the lintels, shortening their actual bearing[ ] (in other words, widening the space which can be bridged between column and column) and giving a workmanlike appearance of stability to the construction at this point. the idea of the division of the column into two sections, suggested in fig. , is kept up in fig. by treating the lower portion up to the same height with incised decorative carving. the dotted lines on each side in fig. give the outline of the original square column as shown in fig. . the finished column was within that block; it is the business of the architectural designer to get it out.[ ] [footnote : this is the feature called "abacus" (i.e., "tile") in greek architecture, but i am here considering it apart from any special style or nomenclature.] [footnote : "bearing," in building language, is used in a double sense, for the distance between the points of support, and the extent to which the beam rests on the walls. thus a beam which extends feet between the points of support is a beam of feet bearing. if the beam is feet long, so that foot rests on the walls at each end, it has " foot bearing on the wall."] [footnote : none of the forms of column sketched here have any existence in reality. they are purposely kept apart from imitation of accepted forms to get rid of the idea that architecture consists in the acceptance of any particular form sanctioned by precedent.] let us see if we can apply the same kind of process of evolving expression in regard to a building. we will take again the very simplest form of building (fig. ), a square house with a door in the center and uniform rows of windows. there cannot be said to be any architectural expression in this. there is no base or plinth at all, no treatment of the wall. the slight projection at the eaves is only what is necessary to keep the rain from running down the walls, and facilitate the emptying of the gutters, and the even spacing of the windows is essential for constructive reasons, to keep the masses of wall over each other, and keep the whole in a state of equally balanced pressure. the first thing we should do in endeavoring to give some expression to the building would be to give it a base or plinth (fig. ), and to mark that and the cornice a little more decidedly by mouldings and a line of paneling at the plinth. [illustration: figs. and ] the house being obviously in three stories, we should give it some echo externally of this division into horizontal stages by horizontal mouldings, or what are called in architectural phraseology "string courses," not necessarily exactly at the floor levels, but so as to convey the idea of horizontal division; observing here, as in the case of the wall and column, that we should take care not to divide the height into equal parts, which is very expressionless. in this case we will keep the lower string close down on the ground floor windows, and keep these rather low, thus showing that the ground floor apartments are not the most important; while the fact that the first floor ones are so is conversely made apparent by keeping these windows rather higher, putting a double string course over them, and a slight extra depth of moulding, forming a kind of cornice over each. the space left between these and the roof, in which the attic windows are placed, is treated with a series of mullions and panelings, into which the attic windows are worked, as part of the series of openings; this gives a little richness of effect to the top story, and a continuity of treatment, which binds the whole series of windows together. to have treated the whole of the walls and windows in this way would have been merely throwing away labor; what little effect it has consists in the "character" given by the contrast of this top story treatment with the plain wall surfaces below. the last thing is to emphasize the door, as the principal opening in the walls, and quite distinct in use and meaning from the other openings, by giving it a little architectural frame or setting, which may be done in many ways, but in this case is done by the old fashioned device (not very logical certainly) of putting a little entablature over it, and a column on either side; there is, however, this to be said for it, that the projecting tablature forms a semi-porch, protecting those at the door somewhat from rain; it must be carried in some way, and columns are the readiest and most seemly manner of doing it, and they also form, practically, something of a weather screen; the bases on which they stand also form a framework or inclosing wall for the steps, which are thus made part of the architectural design, instead of standing out as an eyesore, as on fig. . we have now given the house a little general expression, but it still is vague in its design as far as regards the distribution of the interior; we do not know whether the first floor, for instance, is one large room, or two or more rooms, or how they are divided; and the little house is very square and prim in effect. let us try grouping the windows a little, and at the same time breaking up the flat surface of the front wall (fig. ). here, as before, we have divided the building by a horizontal string, but only by one main one on the first floor level, keeping the same contrast, however, between a richer portion above and a plainer portion below; we have divided the building vertically, also, by two projecting bays finishing in gables, thus breaking also the skyline of the roof, and giving it a little picturesqueness, and we have grouped the windows, instead of leaving them as so many holes in the wall at equal distances. the contrast between the ground and first floor windows is more emphatic; and it is now the more evident that the upper floor rooms are the best apartments, from their ample windows; it is also pretty evident that the first floor is divided into two main rooms with large bay windows, and a smaller room or a staircase window, between them; the second floor windows are also shifted up higher, the two principal ones going in to the gables, showing that the rooms below them have been raised in height. windows carried up the full height of these rooms, however, might be too large either for repose internally or for appearance externally, so the wall intervening between the top of these and the sill of the gables is a good field for some decorative treatment, confined to the bays, so as to assist in separating them from the straight wall which forms the background to them. [illustration: fig. ] so far we have treated our building only as a private house. without altering its general scale and shape we may suggest something entirely different from a private house. on fig. , we have tried to give a municipal appearance to it, as if it were the guild hall of a small country town. the plain basement and the wide principal doorway, and the row of three very large equal-spaced windows above, render it unquestionable that this is a building with a low ground story, and one large room above. a certain "public building" effect is given to it by the large and enriched cornice with balustrade above and paneling below, and by the accentuation of the angles by projecting piers, and by the turrets over them, which give it quite a different character from that of a private house. [illustration: fig. ] if, on the other hand, the building were the free library and reading room of the same small country town, we should have little doubt of this if we saw it as in fig. , with the walls all blank (showing that they are wanted for ranging something against, and cannot be pierced for windows), and windows only in the upper portion. similarly, if we want to build it as the country bank, we should have to put the large windows on the ground floor, bank clerks wanting plenty of light, and the ground story being always the principal one; and we might indulge the humor of giving it a grim fortress-like strength by a rusticated plinth (i.e., stones left or worked rough and rock-like) and by very massive piers between the windows, and a heavy cornice over them; the residential upper floor forming a low story subordinate to the bank story. it is true this would not satisfy a banker, who always wants classic pilasters stuck against the walls, that being his hereditary idea of bank expression in architecture. [illustration: figs. and ] now if we proceed to take to pieces the idea of architectural design, and consider wherein the problem of it consists, we shall find that it falls into a fourfold shape. it consists first in arranging the plan; secondly, in carrying up the boundary lines of this plan vertically in the shape of walls; thirdly, in the method of covering in the space which we have thus defined and inclosed; and, fourthly, in the details of ornamentation which give to it the last and concluding grace and finish. all building, when it gets beyond the mere wall with which we began, is really a method of covering in a space, or, if we may put it so, a collection of spaces, marked out and arranged for certain purposes. the first thing that the architect has to do is to arrange these spaces on the ground so that they may conveniently meet the necessary requirements of the building. convenience and practical usefulness come first; but in any building which is worth the name of architecture something more than mere convenience has to be kept in mind, even in the arrangement of the plan upon the site. it is to be a combination of convenience with effectiveness of arrangement. we shall probably find that some one compartment of the plan is of paramount importance. we have to arrange the interior so that this most important compartment shall be the climax of the plan. the entrance and the other subsidiary compartments must be kept subordinate to it, and must lead up to it in such a manner that the spectator shall be led by a natural gradation from the subsidiary compartments up to the main one, which is the center and _raison d'etre_ of the whole--everything in the lines of the plan should point to that. this is the great _crux_ in the planning of complicated public buildings. a visitor to such a building, unacquainted with it previously, ought to have no difficulty in finding out from the disposition of the interior which are the main lines of route, and when he is on the line leading him up to the central feature of the plan. there are public buildings to be found arranged on what may be called the rabbit warren system, in which perhaps a great number of apartments are got upon the ground, but which the visitor is obliged laboriously to learn before he can find his way about them. that is not only inconvenient but inartistic planning, and shows a want of logic and consideration, and, in addition to this, a want of feeling for artistic effect. i saw not long ago, for instance, in a set of competitive designs for an important public building, a design exhibiting a great deal of grace and elegance in the exterior architectural embellishment, but in which the principal entrance led right up to a blank wall facing the entrance, and the spectator had to turn aside to the left and then to the right before finding himself on the principal axis of the plan. that is what i should call inartistic or unarchitectural planning. the building may be just as convenient when you once know its dodges, but it does not appear so, and it loses the great effect of direct vista and climax. an able architect, who had given much thought to a plan of a large building of this kind, said to me, in showing me his plan, with a justifiable gratification in it, "it has cost me endless trouble, but it is a satisfaction to feel that you have got a plan with backbone in it." that is a very good expression of what is required in planning a complicated building, but few outsiders have any notion of the amount of thought and contrivance which goes to the production of a plan "with backbone;" a plan in which all the subordinate and merely practical departments shall be in the most convenient position in regard to each other, and yet shall all appear as if symmetrically and naturally subordinate to the central and leading feature; and if the public had a little more idea what is the difficulty of producing such a plan, they would perhaps do a little more justice to the labors of the man who contrives the plan, which they think such an easy business; and no doubt it may appear an easy business, because the very characteristic of a really good plan is that it should appear as if it were quite a natural and almost inevitable arrangement. just as it is said in regard to literature that easy writing is hard reading, so, in regard to planning, it is the complicated and rabbit warren plans that are the easiest to make, because it is just doing what you please; it is the apparently perfectly simple and natural plan which springs from thought and contrivance. then there is the next step of raising the walls on the plan, and giving them architectural expression. this must not be thought of as an entirely separate problem, for no truly architectural intellect will ever arrange a plan without seeing generally, in his mind's eye, the superstructure which he intends to rear upon it; but the detailed treatment of this forms a separate branch of the design. then comes the third and very important problem--the covering in of the space. next to the plan, this is the most important. all building is the covering over of a space, and the method of covering it over must be foreseen and provided for from the outset. it largely influences the arrangement of the plan. if there were no roofing, you could arrange the walls and carry them up pretty much as you chose, but the roofing of a large space is another matter. it requires extra strength at certain points, where the weight of the roof is concentrated, and it has to be determined whether you will employ a method of roofing which exercises only a vertical pressure on the walls, like the lid of a box, or one which, like an arch, or a vault, or a dome, is abutting against the walls, and requires counterforts to resist the outward thrust of the roof. we shall come upon this subject of the influence of the roof on the design of the substructure more in detail later on. then, if the plan is convenient and effective, the walls carried up with the architectural expression arising from the placing and grouping of the openings, and the proper emphasizing of the base and the cornice, and the horizontal stages (if any) of the structure, and the roof firmly and scientifically seated on the walls; after all these main portions of the structure are designed logically and in accordance with one another and with the leading idea of the building, then the finishing touches of expression and interest are given by well designed and effective ornamental detail. here the designer may indulge his fancy as he pleases, as far as the nature of the design is concerned, but not, if you please, as far as its position and distribution are concerned. there the logic of architecture still pursues us. we may not place ornament anywhere at haphazard on a building simply because it looks pretty. at least, to do so is to throw away great part of its value. for everything in architectural design is relative; it is to be considered in relation to the expression and design of the whole, and ornament is to be placed where it will emphasize certain points or certain features of the building. it must form a part of the grouping of the whole, and be all referable to a central and predominating idea. a building so planned, built, and decorated becomes, in fact, what all architecture--what every artistic design in fact should be--an organized whole, of which every part has its relation to the rest, and from which no feature can be removed without impairing the unity and consistency of the design. you may have a very good, even an expressive, building with no ornament at all if you like, but you may not have misplaced ornament. that is only an excrescence on the design, not an organic portion of it. i have thought that it would be of use to those who are unacquainted with architectural procedure in delineating architecture by geometrical drawings if i took the opportunity of illustrating very briefly the philosophy of elevations, plans, and sections, which many non-professional people certainly do not understand. [illustration: figs. through ] a simple model of a building, like that in fig. , will serve the purpose, as the principle is the same in the most complicated as in the simplest building. it must be remembered that the object of architectural drawings on the geometrical system is not to show a picture of the building, but to enable the designer to put together his design accurately in all its parts, according to scale, and to convey intelligible and precise information to those who have to erect the building. a perspective drawing like fig. is of no use for this purpose. it shows generally what the design is, but it is impossible to ascertain the size of any part by scale from it, except that if the length of one line were given it would be possible, by a long process of projection and calculation, to ascertain the other sizes. the _rationale_ of the architect's geometrical drawings is that on them each plane of the building (the front, the side, the plan, etc.) is shown separately and without any distortion by perspective, and in such a manner that every portion is supposed to be opposite to the eye at once. only the width of any object on one side can be shown in this way at one view; for the width of the return side you have to look to another drawing; you must compare the drawings in order to find out those relative proportions which the perspective view indicates to the eye at a glance; but each portion of each side can be measured by reference to a scale, and its precise size obtained, which can only be guessed at roughly from the perspective drawing. thus the side of the model is shown in fig. , the end in fig. ; the two together give the precise size and proportions of everything outside to scale, except the projection of the pilasters. this has to be got at from the plan and section. everything being drawn on one plane, of course surfaces which are sloping on one elevation are represented as flat in the other. for instance, on no. the raking line of the sloping roof is shown at n. so we know the slope of the roof, but we do not know to what length it extends the other way. this is shown on fig. , where the portion showing the roof is also marked n, and it will be seen that the surface which is sloping in fig. is seen in the side elevation only as a space between a top and bottom line. we see the length of the roof here, and its height, but for its slope we go to the end elevation. neither elevation tells us, however, what is inside the building; but the section (fig. ) shows us that it has an arched ceiling, and two stories, a lower and a higher one. the section is the building cut in half, showing the end of the walls, the height and depth of the window openings, the thickness of the floor, etc., and as all parts which are opposite the eye are shown in the drawing, the inside of the cross wall at the end of the building is shown as a part of the section drawing, between the sectional walls. in fig. the section is sketched in perspective, to show more clearly what it means. another section is made lengthwise of the building (fig. ). it is customary to indicate on the plan by dotted lines the portion through which the section is supposed to be made. thus on the plans the lines a b and c d are drawn, and the corresponding sections are labeled with the same lines. as with the elevation, one section must be compared with another to get the full information from them. thus in fig. , the ceiling, m, is shown as a semicircle; in fig. , it is only a space between the top and bottom lines. it is, certainly, shaded here to give the effect of rotundity, but that is quite a superfluity. on fig. the height of the side windows is shown at f, and the thickness of the wall in which they are made. in fig. (f) their width and spacing are shown. in fig. some lines drawn across, one over the other, are shown at h. these are the stairs, of which in this section we see only the fronts, or risers, so that they appear merely as lines (showing the edge of each step) drawn one over the other. at h on the plan, fig. , we again see them represented as a series of lines, but here we are looking down on the top of them, and see only the upper surfaces, or "treads," the edges again appearing as a series of lines. at h on the longitudinal section, we see the same steps in section, and consequently their actual slope, which, however, could have been calculated from figs. and , by putting the heights shown in section with the width shown in plan. the plan, fig. , shows the thickness and position on the floor of the pillars, g g. their height is shown in the sections. the plan of a building is merely a horizontal section, cutting off the top, and looking down on the sectional top of the walls, so as to see all their thicknesses. i have drawn (fig. ) a perspective sketch of one end of the plan (fig. ) of the building, on the same principle as was done with the section (fig. ), in order to show more intelligibly exactly what it is that a plan represents--the building with the upper part lifted off. returning for a moment to the subject of the relation between the plan and the exterior design, it should be noted that the plan of a building being practically the first consideration, and the basis of the whole design, the latter should be in accordance with the principle of disposition of the plan. for example, if we have an elevation (shown in diagram) showing two wings of similar design on either side of a center, designed so as to convey the idea of a grand gallery, with a suite of apartments on either side of similar importance--if the one side only of the plan contains such a suite, and the opposite side is in reality divided up into small and inferior rooms, filled in as well as may be behind the architectural design--the whole design is in that case only a blind or screen, giving a false exterior symmetry to a building which is not so planned. this is an extreme case (or might be called so if it were not actually of pretty frequent occurrence); but it illustrates in a broad sense a principle which must be carried out in all cases, if the architecture is to be a real expression of the facts of the building. in this lecture, which is concerned with general principles, a word may fittingly be said as to the subject of _proportion_, concerning which there are many misapprehensions. the word may be, and is, used in two senses, first in regard to the general idea suggested in the words "a well proportioned building." this expression, often vaguely used, seems to signify a building in which the balance of parts is such as to produce an agreeable impression of completeness and repose. there is a curious kind of popular fallacy in regard to this subject, illustrated in the remark which used to be often made about st. peter's, that it is so well proportioned that you are not aware of its great size, etc.--a criticism which has been slain over and over again, but continues to come to life again. the fact that this building does not show its size is true. but the inference drawn is the very reverse of the truth. one object in architectural design is to give full value to the size of a building, even to magnify its apparent size; and st. peter's does not show its size, because it is _ill_ proportioned, being merely like a smaller building, with all its parts magnified. hence the deception to the eye, which sees details which it is accustomed to see on a smaller scale, and underrates their actual size, which is only to be ascertained by deliberate investigation. this confusion as to scale is a weakness inherent in the classical forms of columnar architecture, in which the scale of all the parts is always in the same proportion to each other and to the total size of the building so that a large doric temple is in most respects only a small one magnified. in gothic architecture the scale is the human figure, and a larger building is treated, not by magnifying its parts, but by multiplying them. had this procedure been adopted in the case of st. peter's, instead of merely treating it with a columnar order of vast size, with all its details magnified in proportion, we should not have the fault to find with it that it does not produce the effect of its real size. in another sense, the word "proportion" in architecture refers to the system of designing buildings on some definite geometrical system of regulating the sizes of the different parts. the greeks certainly employed such a system, though there are not sufficient data for us to judge exactly on what principle it was worked out. in regard to the parthenon, and some other greek buildings, mr. watkiss lloyd has worked out a very probable theory, which will be found stated in a paper in the "transactions of the institute of architects." vitruvius gives elaborate directions for the proportioning of the size of all the details in the various orders; and though we may doubt whether his system is really a correct representation of the greek one, we can have no doubt that some such system was employed by them. various theorists have endeavored to show that the system has prevailed of proportioning the principal heights and widths of buildings in accordance with geometrical figures, triangles of various angles especially; and very probably this system has from time to time been applied, in gothic as well as in classical buildings. this idea is open to two criticisms, however. first, the facts and measurements which have been adduced in support of it, especially in regard to gothic buildings, are commonly found on investigation to be only approximately true. the diagram of the section of the building has nearly always, according to my experience, to be "coaxed" a little in order to fit the theory; or it is found that though the geometrical figure suggested corresponds exactly with some points on the plan or section, these are really of no more importance than other points which might just as well have been taken. the theorist draws our attention to those points in the building which correspond with his geometry, and leaves on one side those which do not. now it may certainly be assumed that any builders intending to lay out a building on the basis of a geometrical figure would have done so with precise exactitude, and that they would have selected the most obviously important points of the plan or section for the geometrical spacing. in illustration of this point, i have given (fig. ) a skeleton diagram of a roman arch, supposed to be set out on a geometrical figure. the center of the circle is on the intersection of lines connecting the outer projection of the main cornice with the perpendiculars from those points on the ground line. this point at the intersection is also the center of the circle of the archway itself. but the upper part of the imaginary circle beyond cuts the middle of the attic cornice. if the arch were to be regarded as set out in reference to this circle, it should certainly have given the most important line--the top line, of the upper cornice, not an inferior and less important line; and that is pretty much the case with all these proportion theories (except in regard to greek doric temples); they are right as to one or two points of the building, but break down when you attempt to apply them further. it is exceedingly probable that many of these apparent geometric coincidences really arise, quite naturally, from the employment of some fixed measure of division in setting out buildings. thus, if an apartment of somewhere about feet by feet is to be set out, the builder employing a foot measure naturally sets out exactly feet one way and feet the other way. it is easier and simpler to do so than to take chance fractional measurements. then comes your geometrical theorist, and observes that "the apartment is planned precisely in the proportion of six to five." so it is, but it is only the philosophy of the measuring-tape, after all. secondly, it is a question whether the value of this geometrical basis is so great as has sometimes been argued, seeing that the results of it in most cases cannot be judged by the eye. if, for instance, the room we are in were nearly in the proportion of seven in length to five in width, i doubt whether any of us here could tell by looking at it whether it were truly so or not, or even, if it were a foot out one way or the other, in which direction the excess lay; and if this be the case, the advantage of such a geometrical basis must be rather imaginary than real. [illustration: figs. through ] having spoken of plan as the basis of design, i should wish to conclude this lecture by suggesting also, what has never to my knowledge been prominently brought forward, that the plan itself, apart from any consideration of what we may build up upon it, is actually a form of artistic thought, of architectural poetry, so to speak. if we take three such plans as those shown in figs. , , and , typical forms respectively of the egyptian, greek, and gothic plans, we certainly can distinguish a special imaginative feeling or tendency in each of them. in the egyptian, which i have called the type of "mystery," the plan continually diminishes as we proceed inward. in the third great compartment the columns are planted thick and close, so as to leave no possibility of seeing through the building except along a single avenue of columns at a time. the gloom and mystery of a deep forest are in it, and the plan finally ends, still lessening as it goes, in the small and presumably sacred compartment to which all this series of colonnaded halls leads up. in the greek plan there is neither climax nor anti-climax, only the picturesque feature of an exterior colonnade encircling the building and surrounding a single oblong compartment. it is a rationalistic plan, aiming neither at mystery nor aspiration. in the plan of rheims (fig. ) we have the plan of climax or aspiration; as in the egyptian, we approach the sacred portion through a long avenue of piers; but instead of narrowing, the plan extends as we approach the shrine. i think it will be recognized, putting aside all considerations of the style of the superstructure on these plans, that each of them in itself represents a distinct artistic conception. so in the plan of the pantheon (fig. ), this entrance through a colonnaded porch into a vast circular compartment is in itself a great architectural idea, independently of the manner in which it is built up. [illustration: figs. through ] we may carry out this a little further by imagining a varied treatment on plan of a marked-out space of a certain size and proportion, on which a church of some kind, for instance, is to be placed. the simplest idea is to inclose it round with four walls as a parallelogram (fig. ), only thickening the walls where the weight of the roof principals comes. but this is a plan without an idea in it. the central or sacred space at the end is not expressed in the plan, but is merely a railed-off portion of the floor. the entrance is utterly without effect as well as without shelter. if we lay out our plan as in fig. , we see that there is now an idea in it. the two towers, as they must evidently be, form an advanced guard of the plan, the recessed central part connecting them gives an effective entrance to the interior; the arrangement in three aisles gives length, the apse at the end incloses and expresses the _sacrarium_, which is the climax and object of the plan. the shape of the ground, however, is not favorable to the employment of a long or avenue type of plan, it is too short and square; let us rather try a plan of the open area order, such as fig . this is based on the short-armed greek cross, with an open center area; again there is an "advanced guard" in the shape of an entrance block with a porch; and the three apses at the end give architectural emphasis to the _sacrarium_. fig. is another idea, the special object of which is to give an effect of contrast between the entrance, approached first through a colonnaded portico, then through an internal vestibule, lighted from above, and flanked by rows of small coupled columns; then through these colonnaded entrances, the inner one kept purposely rather dark, we come into an interior expanding in every direction; an effect of strong contrast and climax. if our plot of ground again be so situated that one angle of it is opposite the vista of two or more large streets, there and nowhere else will be the salient angle, so to speak, of the plan, and we can place there a circular porch--which may, it is evident, rise into a tower--and enter the interior at the angle instead of in the center; not an effective manner of entering as a rule, but quite legitimate when there is an obvious motive for it in the nature and position of the site. a new feature is here introduced in the circular colonnade dividing the interior into a central area and an aisle. each of these plans might be susceptible of many different styles of architectural treatment; but quite independently of that, it will be recognized that each of them represents in itself a distinct idea or invention, a form of artistic arrangement of spaces, which is what "plan," in an architectural sense, really means. * * * * * the lowe incandescent gas burner. this burner is in the form of a cylinder made of a composition in which magnesium predominates, and gives a light of candle power with a consumption of three and one-half cubic feet of gas per hour. [illustration] the cylinder to be heated to incandescence is firmly held in place on a metal spindle, which is slowly revolved by means of an ingenious clock-work in the base of the fixture. the arrangement is such that by turning off the gas the clock-work is stopped, and by the turning on of the gas, it is again set in motion. the movement of the spindle is so slow that a casual observer would not notice it, there being only one revolution made in twenty-four hours. the object of this movement is to continually present new surface to be heated, as that which is exposed to the high temperature wears away, similarly to the carbons used in electric lighting, though much more slowly. these burners can be made of , candle power, down to fifty candle power. pure oxygen can now be obtained from the atmosphere at a cost of about twenty-five cents per , cubic feet, and the small amount required to supplement the fuel water gas in producing this light can be supplied under proper pressure from a very small pipe, which can be laid in the same trench with the fuel gas pipe, at much less cost than is required to carry an electric wire to produce an equal amount of light. the oxygen pipe necessary to carry the gas under pressure need not exceed an inch and a half in diameter to supply , lamps of , candle power each. the only reason why this burner has not been further perfected and placed upon the market is because of the continual preoccupation of prof. lowe in other lines of invention, and the amount of attention required by his large business interests. besides, the field for its usefulness has been limited, as cheap fuel gas has only just begun to be generally introduced. now, however, that extensive preparations are being made for the rapid introduction of the lowe fuel gas system into various cities, this burner will receive sufficient attention to shortly complete it for general use in large quantities. it is a more powerful and at the same time a softer light than is the electric incandescent or the arc light. the light-giving property of a burner of , candle power would not cost more than one cent for ten hours' lighting, and the cylinder would only require to be changed once a week; whereas the carbons of arc lights are changed daily. the cost of the gas required to maintain such a lamp ten hours would be six cents, allowing the same profit on the gas as when it is sold for other heating purposes. the lamps complete will cost much less than the present electric lamps, and after allowing a large profit to companies supplying them, will not cost consumers more than one-fourth as much as arc lamps, and will give a much clearer and steadier light. since prof. lowe perfected his first incandescent burner great progress has been made in this line of invention, and it is no wonder that the attention of the whole gas fraternity of the country has been drawn to the subject of cheap fuel water gas, which is so admirably adapted to all purposes of heat, light, and power. while there is no doubt that light can be more cheaply produced by incandescence obtained by the use of fuel water gas than by any other means, still a large amount of electric lighting will continue to hold its position, and the electric system will gain ground for many uses. but the electric light also can be more economically produced when fuel water gas is used as power to revolve the dynamos. therefore, we believe it to be for the best interests of every gas company that would move in the line of progress to commence without delay to make preparations for the introduction of fuel water gas, if, at first, only as supplementary to their present illuminating gas business.-_progressive age._ * * * * * progress of the sorghum sugar industry. we are indebted to prof. e.b. cowgill, of kansas, for a copy of his recent report to the kansas state board of agriculture concerning the operations of the parkinson sugar works, at fort scott, kansas. the report contains an interesting historical sketch of the various efforts heretofore made to produce sugar from sorghum, none of which proved remunerative until , when the persevering efforts of a few energetic individuals, encouraged and assisted by a small pecuniary aid from government, were crowned with success, and gave birth, it may justly be said, to a new industry which seems destined shortly to assume gigantic proportions and increase the wealth of the country. we make the following abstracts from the report: the sorghum plant was introduced into the united states in - , by the patent office, which then embraced all there was of the united states department of agriculture. its juice was known to be sweetish, and chemists were not long in discovering that it contained a considerable percentage of some substance giving the reactions of cane sugar. the opinion that the reactions were due to cane sugar received repeated confirmations in the formation of true cane sugar crystals in sirups made from sorghum. yet the small amounts that were crystallized, compared with the amounts present in the juices as shown by the analyses, led many to believe that the reactions were largely due to some other substance than cane sugar. during the years to , inclusive, while dr. peter collier was chief chemist of the department of agriculture, much attention was given to the study of sorghum juices from canes cultivated in the gardens of the department at washington. dr. collier became an enthusiastic believer in the future greatness of sorghum as a sugar producing plant, and the extensive series of analyses published by him attracted much attention. as a result large sugar factories were erected and provided with costly appliances. hon. john bennyworth erected one of these at larned, in kansas. s.a. liebold & co. subsequently erected one at great bend. sterling and hutchinson followed with factories which made considerable amounts of merchantable sugar at no profit. the factory at sterling was erected by r.m. sandy & co., of new orleans, and while the sirup produced paid the expenses of the factory, not a crystal of sugar was made. the factory then, in , changed hands, and passed under the superintendency of prof. m.a. scovell, then of champaign, illinois, who, with prof. webber, had worked out, in the laboratories of the illinois industrial university, a practical method for obtaining sugar from sorghum in quantities which at prices then prevalent would pay a profit on the business. but prices declined, and after making sugar for two years in succession, the sterling factory succumbed. the hutchinson factory at first made no sugar, but subsequently passed under the management of prof. m. swenson, who had successfully made sugar in the laboratory of the university of wisconsin. large amounts of sugar were made at a loss, and the hutchinson factory closed its doors. in , hon. w.l. parkinson fitted up a complete sugar factory at ottawa, and for two years made sugar at a loss. mr. parkinson was assisted during the first year by dr. wilcox, and during the second year by prof. swenson. much valuable information was developed by the experience in those several factories, but the most important of all was the fact that, with the best crushers, the average extraction did not exceed half of the sugar contained in the cane. it was known to scientists and well informed sugar makers in this country that the process of diffusion was theoretically efficient for the extraction of sugar from plant cells, and that it had been successfully applied by the beet sugar makers of europe for this purpose. in , prof. h.w. wiley, chief chemist of the department of agriculture, made an exhaustive series of practical experiments in the laboratories of the department on the extraction of the sugars from sorghum by the diffusion process, by which the extraction of at least per cent. of the total sugars present was secured. the kansas delegation in congress became interested. senator plumb made a thorough study of the entire subject, and, with the foresight of statesmanship, gave his energies to the work of securing an appropriation of $ , for the development of the sugar industry, which was granted in , and fifty thousand dollars more was added in to the agricultural appropriation bill. this was expended at ottawa, kansas, and in louisiana. in that year judge parkinson, at fort scott, organized the parkinson sugar company. taking up the work when all others had failed, this company has taken a full share of the responsibilities and losses, until it has at last seen the northern sugar industry made a financial success. the report of showed such favorable results that in the house made an appropriation of $ , , to be used in louisiana, new jersey, and kansas. a new battery and complete carbonatation apparatus were erected at fort scott. about $ , of the appropriation was expended here in experiments in diffusion and carbonatation. last year ( ) the fort scott management made careful selection of essential parts of the processes already used, omitted non-essential and cumbrous processes, availed themselves of all the experience of the past in this country, and secured a fresh infusion of experience from the beet sugar factories of germany, and attained the success which finally places sorghum sugar making among the profitable industries of the country. the success has been due, first, to the almost complete extraction of the sugars from the cane by the diffusion process; second, the prompt and proper treatment of the juice in defecating and evaporating; third, the efficient manner in which the sugar was boiled to grain in the strike pan. total number tons of cane bought , " " " seed tops bought ----- total number tons of field cane , there was something over acres planted. some of it failed to come at all, some "fell upon the rocky places, where they had not much earth, and when the sun was risen they were scorched;" so that, as nearly as we can estimate, about acres of cane were actually harvested and delivered at the works. this would make the average yield of cane ½ tons per acre, or $ per acre in dollars and cents. total product of the season, . sugar, , lb., @ ¾c $ , " state bounty, @ c , --------- $ , sirups, , gals,(estimated) @ c. , seed (estimated) , -------- value of total product $ , total cost. cane, , tons,@ $ $ , seed, tons, @ $ , ------- $ , labor bill from august to october , including labor for department experiments , coal, including all experiments , salaries, etc. , insurance, sundries, etc. , ---------- total $ , ========== total value $ , total cost , ---------- net $ , to be paid by the department , ---------- total profit for season's work, $ , outline of the processes of sorghum sugar making. as now developed, the processes of making sugar from sorghum are as follows: _first_, the topped cane is delivered at the factory by the farmers who can grow it. _second_, the cane is cut by a machine into pieces about one and a quarter inches long. _third_, the leaves and sheaths are separated from the cut cane by fanning mills. _fourth_, the cleaned cane is cut into fine bits called chips. _fifth_, the chips are placed in iron tanks, and the sugar "diffused," soaked out with hot water. _sixth_, the juice obtained by diffusion has its acids nearly or quite neutralized with milk of lime, and is heated and skimmed. _seventh_, the defecated or clarified juice is boiled to a semi-sirup in vacuum pans. _eighth_, the semi-sirup is boiled "to grain" in a high vacuum in the "strike pan." _ninth_, the mixture of sugar and molasses from the strike pan is passed through a mixing machine into centrifugal machines which throw out the molasses and retain the sugar. the process of the formation of sugar in the cane is not fully determined, but analyses of canes made at different stages of growth show that the sap of growing cane contains a soluble substance having a composition and giving reactions similar to starch. as maturity approaches, grape sugar is also found in the juice. a further advance toward maturity discloses cane sugar with the other substances, and at full maturity perfect canes contain much cane sugar and little grape sugar and starchy matter. in sweet fruits the change from grape sugar to cane sugar does not take place, or takes place but sparingly. the grape sugar is very sweet, however. cane sugar, called also sucrose or crystallizable sugar, when in dilute solution is changed very readily into grape sugar or glucose, a substance which is much more difficult than cane sugar to crystallize. this change, called inversion, takes place in over-ripe canes. it sets in very soon after cutting in any cane during warm weather; it occurs in cane which has been injured by blowing down, or by insects, or by frost, and it probably occurs in cane which takes a second growth after nearly or quite reaching maturity. to insure a successful outcome from the operations of the factory, the cane must be so planted, cultivated and matured as to make the sugar in its juice. it must be delivered to the factory very soon after cutting, and it must be taken care of before the season of heavy frosts. the work at the factory. the operations of the factory are illustrated in the large diagram. the first cutting is accomplished in the ensilage or feed cutter at e. this cutter is provided with three knives fastened to the three spokes of a cast iron wheel which makes about revolutions per minute, carrying the knives with a shearing motion past a dead knife. by a forced feed the cane is so fed as to be cut into pieces about one and a quarter inches long. this cutting frees the leaves and nearly the entire sheaths from the pieces of cane. by a suitable elevator, f, the pieces of cane, leaves and sheaths are carried to the second floor. the elevator empties into a hopper, below which a series of four or five fans, g, is arranged one below the other. by passing down through these fans the cane is separated from the lighter leaves, much as grain is separated from chaff. the leaves are blown away, and finally taken from the building by an exhaust fan. this separation of the leaves and other refuse is essential to the success of the sugar making, for in them the largest part of the coloring and other deleterious matters are contained. if carried into the diffusion battery, these matters are extracted (see reports of chemical division, u.s. department of agriculture), and go into the juice with the sugar. as already stated, the process of manufacturing sugar is essentially one of separation. the mechanical elimination of these deleterious substances at the outset at once obviates the necessity of separating them later and by more difficult methods, and relieves the juice of their harmful influences. from the fans the pieces of cane are delivered by a screw carrier to an elevator which discharges into the final cutting machine on the third floor. this machine consists of an eight inch cast iron cylinder, with knives like those of a planing machine. it is really three cylinders placed end to end in the same shaft, making the entire length eighteen inches. the knives are inserted in slots and held in place with set screws. the cylinder revolves at the rate of about twelve hundred per minute, carrying the knives past an iron dead knife, which is set so close that no cane can pass without being cut into fine chips. from this cutter the chips of cane are taken by an elevator and a conveyer, k, to cells, mm, of the diffusion battery. the conveyer passes above and at one side of the battery, and is provided with an opening and a spout opposite each cell of the battery. the openings are closed at pleasure by a slide. a movable spout completes the connection with any cell which it is desired to fill with chips. what is diffusion? the condition in which the sugars and other soluble substances exist in the cane is that of solution in water. the sweetish liquid is contained, like the juices of plants generally, in cells. the walls of these cells are porous. it has long been known that if a solution of sugar in water be placed in a porous or membraneous sack, and the sack placed on water, an action called osmosis, whereby the water from the outside and the sugar solution from the inside of the sack each pass through, until the liquids on the two sides of the membrane are equally sweet. other substances soluble in water behave similarly, but sugar and other readily crystallizable substances pass through much more readily than uncrystallizable or difficultly crystallizable. to apply this properly to the extraction of sugar, the cane is first cut into fine chips, as already described, and put into the diffusion cells, where water is applied and the sugar is displaced. [illustration: fig. --apparatus for manufacture of sorghum by the diffusion process.] the diffusion battery, as used at the parkinson factory, consists of twelve iron tanks. (see diagram.) they are arranged in a line, as shown in diagram, fig. . each has a capacity of seventy-five cubic feet, and by a little packing holds a ton of cane chips. the cells are supported by brackets near the middle, which rest on iron joists. each cell is provided with a heater, through which the liquid is passed in the operation of the battery. the cells are so connected by pipes and valves that the liquid can be passed into the cells, and from cell to cell, at the pleasure of the operator. the bottom of each cell consists of a door, which closes on an annular rubber hose placed in a groove, and filled with water, under a pressure greater than that ever given to the liquids in the cell. this makes a water tight joint whenever the trap door bottom is drawn up firmly against it. the upper part is of cast iron and is jug shaped, and is covered with a lid which is held with a screw on rubber packing. in the jug neck and near the bottom the sides are double, the inner plates being perforated with small holes to let water in and out. the bottoms are double, the inner plates being perforated like the neighboring sides, and for the same purpose. the cells, of whose appearance a fair idea may be had from diagram, fig. , are connected with a water pipe, a juice pipe, a compressed air pipe, and the heaters, by suitable valves. the heaters are connected with a steam pipe. this, and the compressed air pipe, are not shown in the diagram. the water pipe is fed from an elevated tank, which gives a pressure of twelve pounds per square inch the valve connections enable the operator to pass water into the cells at either the top or the bottom; to pass the liquid from any cell to the next, or to the juice pipe through the heater; to separate any cell from any or all others, and to turn in compressed air. now let the reader refer to fig. . [illustration: fig. --diffusion process--manufacture of sorghum sugar.] the cutters are started, and cell is filled with chips. this done, the chips from the cutters are turned into cell ; cell is closed, and cut off from the others, and water is turned into it by opening valve, c, of cell (see fig. ) until it is filled with water among the chips. when is filled with chips, its valve, a, is raised to allow the liquid to pass down into the juice pipe. valve a of is also raised. now the juice pipe fills, and when it is full the liquid flows through valve, a, of , and into the heater between and , and into the bottom of , until is full of water among the chips. (this may be understood by following the course of the arrows shown in the diagrams of and ). valve a of is now screwed down; c is down and b is opened. it will be readily seen by attention to the diagram that this changes the course of the flow so that it will no longer enter at the bottom, but at the top of , as shown by the arrows at cell . it is to be observed that the water is continually pressing in at the top of , and driving the liquid forward whenever a valve is opened to admit it to another cell, heater, or pipe. when cell is full of chips, its valves are manipulated just as were those of . so as each succeeding cell is filled, the manipulation of valves is repeated until cell is filled with liquid. after passing through six cells of fresh chips, this liquid is very sweet, and is drawn off into the measuring tank shown at p in diagram, fig. , and is thence conveyed for subsequent treatment in the factory. to draw this juice from , valve a of is raised to connect the heater between and with the juice pipe. a gate valve in the juice pipe is opened into the measuring tank, and the pressure of water into the top of drives the liquid forward through the bottom of , through the heater, into the top of , out from the bottom of , through the heater into the top of , out from the bottom of , through the heater into the top of , out from the bottom of , through the heater, into the top of , out from the bottom of , through the heater, into the top of , and now out from the bottom of , through the heater, into the juice pipe, and from the juice pipe into the measuring tank. it will be understood that the liquid which is drawn from is chiefly that which was passed into when it was filled with chips. there is doubtless a little mixing as the pressure drives the liquid forward. but the lighter liquid is always pressed in at the top of the cells, so that the mixing is the least possible. the amount of liquid, now called juice, which is drawn from is , liters, or gallons. when this quantity has been drawn into the measuring tank, the gate valve is closed, and the valves connecting with are manipulated as were those of , a measure of juice being drawn in the same way. all this time the water has been passed into the top of , and this is continued until the juice has been drawn from . valve c to cell is now closed, and compressed air is turned into the top of to drive the liquid forward into . after the water has thus been nearly all expelled from , valve a of cell is lowered so as to shut off communication with the juice pipe, and b, of cell is closed. a and b of cell have, it will be observed, been closed or down from the beginning. cell is now isolated from all others. its chips have been exhausted of sugar, and are ready to be thrown out. the bottom of is opened, and the chips fall out into the car, o (see diagram, fig. ), and are conveyed away. immediately on closing valves a and b of cell , c is opened, and the water presses into the top of , as before into the top of , and the circulation is precisely similar to that already described, having taken the place of , of , and so on. when is emptied, takes the first place in the series and so on. when has been filled, it takes the l th place. (the juice pipe returns from the termination of the series, and connects with , making the circuit complete.) the process is continuous, and the best and most economical results are obtained if there is no intermission. one cell should be filled and another emptied every eight minutes, so that in twenty-four hours the number of cells diffused should be one hundred and eighty. what has taken place in the diffusion cells. for the purpose of illustration, let us assume that when it has been filled with chips just as much water is passed into the cell as there was juice in the chips. the process of osmosis or diffusion sets in, and in a few minutes there is as much sugar in the liquid outside of the cane cells as in the juice in these cane cells; i.e., the water and the juice have divided the sugar between them, each taking half. again, assume that as much liquid can be drawn from as there was water added. it is plain that if the osmotic action is complete, the liquid drawn off will be half as sweet as cane juice. it has now reached fresh chips in , and again equalization takes place. half of the sugar from was brought into , so that it now contains one and a half portions of sugar, dissolved in two portions of liquid, or the liquid has risen to three quarters of the strength of cane juice. this liquid having three fourths strength passes to , and we have in one and three fourths portions of liquid, or after the action has taken place the liquid in is seven eighths strength. one portion of this liquid passes to , and we have one and seven eighths portions of sugar in two portions of liquid, or the liquid becomes / strength. one portion of this liquid passes to , and we have in one and fifteen sixteenths portions of sugar in two portions of liquid, or the liquid is / strength. it is now called _juice_. from this time forward a cell is emptied for every one filled. throughout the operation, the temperature is kept as near the boiling point as can be done conveniently without danger of filling some of the cells with steam. diffusion takes place more rapidly at high than at low temperatures, and the danger of fermentation, with the consequent loss of sugar, is avoided. what has happened to the chips. by the first action of water in , ½ of the sugar was left in cell ; by the second ¼ was left, by the third / was left, by the fourth / was left, by the fifth / was left, by the sixth / was left, by the seventh / was left, by the eighth / was left, by the ninth / was left. the fractions representing the strength of the juice on the one hand and the sugar left in each cell on the other hand, after the battery is fully in operation, are not so readily deduced. the theory is easily understood, however, although the computation is somewhat intricate. those who desire to follow the process by mathematical formula are referred to pages and , bulletin no. , chemical division u.s. department of agriculture, where will be found the formula furnished by professor harkness, of the u.s. naval observatory. for the sake of simplifying the explanation, it was assumed that the water added is equal in volume to the juice in a cellful of cane chips. in practice more water is added, to secure more perfect exhaustion of the chips, and with the result of yielding about thirteen volumes of juice for every nine volumes as it exists in the cane, and of extracting . per cent. of all the sugars from the cane, as shown by the report of dr. c.a. crampton, assistant chemist of the u.s. department of agriculture. inversion of sugar in the diffusion cells. in the experiments at fort scott in , much difficulty was experienced on account of inversion of the sugar in the diffusion battery. the report shows that this resulted from the use of soured cane and from delays in the operation of the battery on account of the imperfect working of the cutting and elevating machinery, much of which was there experimental. under the circumstances, however, it became a matter of the gravest importance to find a method of preventing this inversion without in any manner interfering with the other processes. on the suggestion of prof. swenson, a portion of freshly precipitated carbonate of lime was placed with the chips in each cell.[ ] in the case of soured cane, this took up the acid which otherwise produced inversion. in case no harmful acids were present, this chalk was entirely inactive. soured canes are not desirable to work under any circumstances, and should be rejected by the chemist, and not allowed to enter the factory. so, also, delays on account of imperfect machinery are disastrous to profitable manufacturing, and must be avoided. but for those who desired to experiment with deteriorated canes and untried cutting machines, the addition of the calcium carbonate provides against disastrous results which would otherwise be inevitable. [footnote : for this improvement prof. swenson obtained a patent oct. , , the grant of which was recently made the subject of congressional inquiry.] immediately after it is drawn from the diffusion battery the juice is taken from the measuring tanks into the defecating tanks or pans. these are large, deep vessels, provided with copper steam coils in the bottom for the purpose of heating the juice. sufficient milk of lime is added here to nearly or quite neutralize the acids in the juice, the test being made with litmus paper. the juice is brought to the boiling point, and as much of the scum is removed as can be taken quickly. the scum is returned to the diffusion cells, and the juice is sent by a pump to the top of the building, where it is boiled and thoroughly skimmed. these skimmings are also returned to the diffusion cells. this method of disposing of the skimmings was suggested by mr. parkinson. it is better than the old plan of throwing them away to decompose and create a stench about the factory. probably a better method would be to pass these skimmings through some sort of filter, or, perhaps better still, to filter the juice and avoid all skimming. after this last skimming the juice is ready to be boiled down to a thin sirup in the double effect evaporators. these consist of two large closed pans provided within with steam pipes of copper, whereby the liquid is heated. they are also connected with each other and with pumps in such a way as to reduce the pressure in the first to about three fifths and in the second to about one fifth the normal atmospheric pressure. the juice boils rapidly in the first at somewhat below the temperature of boiling water, and in the second at a still lower temperature. the exhaust steam from the engines is used for heating the first pan, and the vapor from the boiling juice in the first pan is hot enough to do all the boiling in the second, and is taken into the copper pipes of the second for this purpose. in this way the evaporation is effected without so great expenditure of fuel as is necessary in open pans, or in single effect vacuum pans, and the deleterious influences of long continued high temperature on the crystallizing powers of the sugar are avoided. from the double effects the sirup is stored in tanks ready to be taken into the strike pan, where the sugar is crystallized. the first chance to pause. at this point the juice has just reached a condition in which it will keep. from the moment the cane is cut in the fields until now, every delay is liable to entail loss of sugar by inversion. after the water is put into the cells of the battery with the chips, the temperature is carefully kept above that at which fermentation takes place most readily, and the danger of inversion is thereby reduced. but with all the precautions known to science up to this point the utmost celerity is necessary to secure the best results. there is here, however, a natural division in the process of sugar making, which will be further considered under the heading of "auxiliary factories." any part of the process heretofore described may be learned in a few days by workmen of intelligence and observation who will give careful attention to their respective duties. boiling the sirup to grain the sugar. this operation is the next in course, and is performed in what is known at the sugar factory as the strike pan, a large air tight iron vessel from which the air and vapor are almost exhausted by means of a suitable pump and condensing apparatus. as is the case with the saccharine juices of other plants, the sugar from sorghum crystallizes best at medium temperature. the process of boiling to grain may be described as follows: a portion of the sirup is taken into the pan, and boiled rapidly _in vacuo_ to the crystallizing density. if in a sirup the molecules of sugar are brought sufficiently near to each other through concentration--the removal of the dissolving liquid--these molecules attract each other so strongly as to overcome the separating power of the solvent, and they unite to form crystals. sugar is much more soluble at high than at low temperatures, the heat acting in this as in almost all cases as a repulsive force among the molecules. it is therefore necessary to maintain a high vacuum in order to boil at a low temperature, in boiling to grain. when the proper density is reached the crystals sometimes fail to appear, and a fresh portion of cold sirup is allowed to enter the pan. this must not be sufficient in amount to reduce the density of the contents of the pan below that at which crystallization may take place. this cold sirup causes a sudden though slight reduction in temperature, which may so reduce the repulsive forces as to allow the attraction among the molecules to prevail, resulting in the inception of crystallization. to discover this requires the keenest observation. when beginning to form, the crystals are too minute to show either form or size, even when viewed through a strong magnifying glass. there is to be seen simply a very delicate cloud. the inexperienced observer would entirely overlook this cloud, his attention probably being directed to some curious globular and annular objects, which i have nowhere seen explained. very soon after the sample from the pan is placed upon glass for observation, the surface becomes cooled and somewhat hardened. as the cooling proceeds below the surface, contraction ensues, and consequently a wrinkling of the surface, causing a shimmer of the light in a very attractive manner. this, too, is likely to attract more attention than the delicate, thin cloud of crystals, and may be even confounded with the reflection and refraction of light, by which alone the minute crystals are determined. the practical operator learns to disregard all other attractions, and to look for the cloud and its peculiarities. when the contents of the pan have again reached the proper density, another portion of sirup is added. the sugar which this contains is attracted to the crystals already formed, and goes to enlarge these rather than to form new crystals, provided the first are sufficiently numerous to receive the sugar as rapidly as it can crystallize. the contents of the pan are repeatedly brought to the proper density, and fresh sirup added as above described until the desired size of grain is obtained, or until the pan is full. good management should bring about these two conditions at the same time. if a sufficient number of crystals has not been started at the beginning of the operation to receive the sugar from the sirup added, a fresh crop of crystals will be started at such time as the crystallization becomes too rapid to be accommodated on the surfaces of the grain already formed. the older and larger crystals grow more rapidly, by reason of their greater attractive force, than the newer and smaller ones on succeeding additions of sirup, so that the disparity in size will increase as the work proceeds. this condition is by all means to be avoided, since it entails serious difficulties on the process of separating the sugar from the molasses. in case this second crop of crystals, called "false grain" or "mush sugar" has appeared, the sugar boiler must act upon his judgment, guided by his experience as to what is to be done. he may take enough thin sirup into the pan to dissolve all of the crystals and begin again, or, if very skillful, he may so force the growth of the false grain as to bring it up to a size that can be worked. the completion of the work in the strike pan leaves the sugar mixed with molasses. this mixture is called _malada_ or _masscuite_. it may be drawn off into iron sugar wagons and set in the hot room above mentioned, in which case still more of the sugar which remains in the uncrystallized state generally joins the crystals, somewhat increasing the yield of "first sugars." at the proper time these sugar wagons are emptied into a mixing machine, where the mass is brought to a uniform consistency. if the sugar wagons are not used, the strike pan is emptied directly into the mixer. the centrifugal machines. from the mixer the melada is drawn into the centrifugal machines. these consist, first, of an iron case resembling in form the husk of mill stones. a spout at the bottom of the husk connects with a molasses tank. within this husk is placed a metallic vessel with perforated sides. this vessel is either mounted or hung on a vertical axis, and is lined with wire cloth. having taken a proper portion of the melada into the centrifugal, the operator starts it to revolving, and by means of a friction clutch makes such connection with the engine as gives it about , revolutions per minute. the centrifugal force developed drives the liquid molasses through the meshes of the wire cloth, and out against the husk, from which it flows off into a tank. the sugar, being solid, is retained by the wire cloth. if there is in the melada the "false grain" already mentioned, it passes into the meshes of the wire cloth, and prevents the passage of the molasses. after the molasses has been nearly all thrown out, a small quantity of water is sprayed over the sugar while the centrifugal is in motion. this is forced through the sugar, and carries with it much of the molasses which would otherwise adhere to the sugar, and discolor it. if the sugar is to be refined, this washing with water is omitted. when the sugar has been sufficiently dried, the machine is stopped, the sugar taken out, and put into barrels for market. simple as the operation of the centrifugals is, the direction of the sugar boiler as to the special treatment of each strike is necessary, since he, better than any one else, knows what difficulties are to be expected on account of the condition in which the melada left the strike pan. capacity of the sugar factory. a plant having a battery like that at fort scott, in which the cells are each capable of containing a ton of cane chips, should have a capacity of tons of cleaned cane, or tons of cane with leaves, or tons of cane as it grows in the field, per day of twenty-four hours. those who have given most attention to the subject think that a battery composed of one and a half ton cells may be operated quite as successfully as a battery of one ton cells. such a battery would have a capacity of tons of field cane per day. the cutting and cleaning apparatus. this consists of modifications of appliances which have long been used. simple as it is, and presenting only mechanical problems, the cutting, cleaning, and evaporating apparatus is likely to be the source of more delays and perplexities in the operation of the sugar factory than any other part. the diffusion battery in good hands works perfectly; the clarification of the juice causes no delays; the concentration to the condition of semi-sirup may be readily, rapidly, and surely effected in apparatus which has been brought to great perfection by long experience, and in many forms; the work at the strike pan requires only to be placed in the hands of an expert; the mixer never fails to do its duty; there are various forms of centrifugal machines on the market, some of which are nearly perfect. if, then, the mechanical work of delivering, cutting, cleaning, and elevating the cane can be accomplished with regularity and rapidity, the operation of a well adjusted sugar factory should proceed without interruption or delay from monday morning to saturday night. the future of the sorghum sugar industry. an acre of land cultivated in sorghum yields a greater tonnage of valuable products than in any other crop, with the possible exception of hay. under ordinary methods of cultivation, ten tons of cleaned cane per acre is somewhat above the average, but under the best cultivation the larger varieties often exceed twelve, while the small early amber sometimes goes below eight tons per acre. let seven and a half tons of cleaned cane per acre be assumed for the illustration. this corresponds to a gross yield of ten tons for the farmer, and at two dollars per ton gives him twenty dollars per acre for his crop. these seven and a half tons of clean cane will yield: pounds of sugar. , pounds of molasses. pounds of seed. , pounds of fodder (green leaves). , pounds of exhausted chips (dried). a total of , pounds. the first three items, which are as likely to be transported as wheat or corn, aggregate , pounds per acre. sorghum will yield seven and a half tons of cleaned cane per acre more surely than corn will yield thirty bushels or wheat fifteen bushels per acre. in the comparison, then, of products which bear transportation, these crops stand as follows: sorghum, at ½ tons, , pounds per acre. corn, at bushels, , pounds per acre. wheat, at bushels, pounds per acre. the sugar from the sorghum is worth say cents per pound; the molasses, ¾ cents per pound; the seed, ½ cent per pound. the sorghum products give market values as follows: pounds sugar at say cents,[ ] $ . . , pounds molasses at say ¾ cents,[ ] $ . . pounds seed at say ½ cent,[ ] $ . . total value of sorghum, less fodder, $ . . the corn crop gives , pounds, at ½ cent $ . . the wheat crop gives pounds, at cent, $ . [footnote : the sugar sold this year at ¾ cents per pound, the molasses at cents per gallon, and the seed at ---- per bushel of pounds. the seed is of about equal value with corn for feeding stock.] thus it will be seen that the sorghum yields to the farmer more than twice as much per acre as either of the leading cereals, and as a gross product of agriculture and manufacture on our own soil more than six times as much per acre as is usually realized from either of these standard crops. * * * * * a new process for producing iron and steel direct from the ore has been brought out in russia. under the new process iron ore, after being submitted to the smelting processes, is taken direct from the furnace to the rolling mill and turned into thin sheets of the finest charcoal iron. at present the process has only been commercially applied with charcoal fuel, but experiments are stated to have shown that equal success can be obtained with coke. the secret of the process lies in the construction of the furnace, which is said to be simple and inexpensive. * * * * * the menges thermo-magnetic generator and motor. we have received from m. menges (of the hague) a most interesting description of an apparatus on which he has been at work for some time past, with the object of generating electricity by the direct conversion of heat, or, as it might be more accurately described, by a more direct conversion than that of an ordinary dynamo. m. menges' apparatus depends, like that of edison, upon the fact that the magnetic metals lose their magnetic permeability at a certain temperature. it differs greatly, however, from its predecessor in important points, especially in the fact that it does not require the aid of any external source of motive power. in edison's pyromagnetic dynamo it will be remembered that it is necessary to provide some small amount of motive power from an extraneous source in order to revolve the shield by which the heat is alternately directed on one half or the other of the armature cores. m. menges' apparatus is, on the contrary, wholly automatic. we proceed to give a free translation of the description furnished us by the inventor. in attempting to employ the thermo-magnetic properties of iron or nickel in the construction of machines for the generation of electricity upon an industrial scale, we are met with the difficulty that the heating and cooling of large masses of metal not only involves great loss of heat, but also requires much time. hence, to obtain a useful effect of any importance, it would appear necessary to employ machines of dimensions altogether impracticable. by the device and method of construction now to be explained this difficulty has, however, been completely overcome. the action of a magnetic pole diminishes so rapidly with the increase of distance that it may suffice to remove the armature to a distance relatively small compared with its own dimensions, or with those of the magnet, in order to reduce the action to a negligible value. but if the magnet, n s, and the armature, a, being at a certain distance, we bring between them a piece of iron or nickel, d, then the magnetic force upon a is immediately and very considerably increased. in modern language, the resistance of the magnetic circuit has been reduced by the introduction of a better magnetic conductor, and the number of lines of force passing through a is proportionately increased. the mass of the piece, d, may, moreover, be relatively small compared with that of n s and a. if d be again withdrawn, the magnetic resistance is increased, and the lines through a are again a minimum. now, it is evident that we can also obtain the same effect by sufficiently heating and cooling the intermediate piece, d; and again, with a broad field we can alter the distribution of the lines at will by heating or cooling one side of this piece or the other. for this reason we will call the piece d the _thermo-magnetic distributor_, or, briefly, the distributor. we will now describe the manner in which this principle has been realized in the practical construction of both a thermo-magnetic generator and motor. [illustration: fig. .] fig. shows an elevation and part section of one of the arrangements employed. fig. is a plan of the same machine (in the latter the ring, _a a_, appearing on a higher plane than it actually occupies). [illustration: fig. .] n s is an electro-magnet, _a a_ the armature, wound as a gramme ring, and fixed to a frame with four arms, which can turn freely upon a pivot midway between the poles. the cross arms of the frame are attached at , , , , fig. . between the magnets and the armature is placed the distributor, _d d_, where it occupies an annular space open above and below. both the magnets and the armature are coated on the sides facing the distributor with mica or some other non-conductor of heat and electricity. the distributor is attached to and supported by the cross arms, so that it turns with the armature. the distributor is composed of a ribbon of iron or nickel, bent into a continuous zigzag. this form has the advantage of presenting, in the cool part of the distributor, an almost direct road for the lines of force between the poles and the armature, thus diminishing the magnetic resistance as far as possible. at the same time the foucault currents are minimized. to the same end it is useful to slit the ribbon, as in fig. . this also facilitates the folding into zigzags. [illustration: fig. .] the distributor is heated at two opposite points on a diameter by the burners, _b b_, above which are the chimneys, _e e_. the cooling of the alternate section is aided by the circulation of cold air, which is effected by means of the draught in the chimneys, _e e_. at the points of lowest temperature a jet of air or water is maintained. the cross arms are insulated with mica or asbestos at the points where they extend from the armature to the distributor. it will now be evident that while the distributor is entirely cool, many of the lines of force pass from n to s without entering the armature core; but if heat is applied at the points and in the figure, so as to increase the magnetic resistance at these points, then a great portion of the lines will leave the distributor, and pass through the armature core. under these conditions, so long as heat is applied at two points equidistant from n and s, we might, if we so pleased, cause the armature to be rotated by an external source of power, and we should then have an e.m.f. generated in the armature coils--that is to say, the machine would work as an ordinary dynamo, and the power expended in driving the armature would be proportionate to the output. suppose next that the points of heating, and with them the alternate points of cooling deg. apart, are shifted round about deg., so that the two hot regions are no longer symmetrically situated in respect to each pole of the field. the distribution of the magnetization has therefore become unsymmetrical, and the iron core is no longer in equilibrium in the magnetic field. we have, in fact, the conditions of schwedoff's experiment upon a larger scale, and if the forces are sufficient to overcome the frictional resistance, a rotation of the ring ensues in the endeavor to restore equilibrium. the regions of heating and cooling being fixed in space, this rotation is continuous so long as the difference of temperature is maintained. the ring in rotating carries with it the armature coils, and of course an e.m.f. is generated in the same way as if the motive power came from an external source. in this respect the machine therefore resembles a motor generator, and the rotation is entirely automatic. the armature coils are connected with a commutator in the usual way, and the field may, of course, be excited either in shunt or in series. m. menges says that the residual magnetization is sufficient in his machine to start the rotation by itself. when the machine is to be used as a motor, it is evident that the windings on the armature core need only be sufficient to supply current to excite the field, or by the use of permanent magnets they may be dispensed with altogether. m. menges has further designed a large number of variations on the original type, varying the arrangement of the several parts, and employing armatures and fields of many different types, such as are already in use for dynamos. in fig. a machine is represented in which the field is external to the armature. [illustration: fig. .] in fig. we have a thermo-magnetic generator, which corresponds to the disk machine in dynamos. similar parts are indicated by the same letters in each of these figures, so that no further detailed description is necessary. [illustration: fig. .] in another modification m. menges proposes to rotate the burners and leave the armature and distributor at rest. but in this case it is evident that the e.m.f. produced would be much less, because the magnetization of the core would only undergo a variation of intensity, and would nowhere be reversed, except, perhaps, just in front of the poles. in machines modeled on the brush type it is evident that the distributor need not be continuous. enough has, however, been said to indicate the extent of the field upon which the principle may be applied.--_the electrician._ * * * * * observations on atmospheric electricity.[ ] [footnote : abstract of a paper read before the british association meeting at manchester, september, .] by prof. l. weber. i will try to give a short report of some experiments i have made during the last year in regard to atmospheric electricity. it was formerly uncertain whether the electrostatic potential would increase by rising from the surface of the earth to more elevated region of the atmosphere or not, and also whether the potential in a normal--that is, cloudless--state of the atmosphere was always positive or sometimes negative. sir william thomson found by exact methods of measuring that the increase of the potential with elevation is very important, and values about volts per meter. that fact is proved by many other observers, especially lately by mr. f. exner, at vienna, who found an increase of to volts per meter. the observations were made by means of an electrometer. in respect of many inconveniences which are connected with the use of an electrometer, i have tried the measurements with a very sensitive galvanometer. in this case it is necessary to apply a separating air exhaust apparatus, for example flame, or a system of points at the upper end of the conductor, which is elevated in the atmosphere. in order to get a constant apparatus, i have used of the finest needles inserted in a metallic ribbon. this system i have raised in the air by means of a captive balloon, or by a kite, which was attached to a conductor of twine or to a twisted line of the finest steel wire. in this way i have attained a height of to meters. when the lower end of the kite line was communicating with the galvanometer whose other terminal was in contact with the earth, a current passed through the galvanometer. for determining the strength of this current i proposed to called a micro-ampere the ^{- } part of an ampere. at the height of about meters in the average the current begins to be regular, and increases at the height of meters to , or , of these units. the increase is very regular, and seems to be a linear function of the height. i have, nevertheless, found the smallest quantities of dust contained in the atmosphere or the lightest veil of cirrus disturbed the measurement very materially, and generally made the potential lower. in negative experiments of this nature i have made at breslau, at the sohneekoppe, and at the "reisengebirge," especially at the last station, an increase of potential was observed, not only by reason of the perpendicular height, but also by reaching such regions of the atmosphere as were situated horizontally to about meters from the utmost steep of the same mountain, sohneekoppe. therefore it must, according to mr. exner, be assumed that the surface of the air presents a surface of equal potential, and that the falling surfaces of high potential were stretched parallel over the plane contours of the air, and more thinly or narrow lying over all the elevated points, as, for example, mountains, church towers, etc. on the basis of these facts i think it easy to explain the electricity of thunder storm clouds, in fact every cloud, or every part of a cloud, may be considered as a leading conductor, such clouds as have for the most part perpendicular height. after being induced the change results by supposing the conduction of electricity either from the upper or from the lower side, according to greater or smaller speed of the air in the height. in the first case the clouds will be charged positive, in the other negative. i am inclined, therefore, to state that the electricity of thunder storm clouds must be considered as a special but disturbed case of the normal electric state of the atmosphere, and that all attempts to explain thunder storm electricity must be based on the study of the normal electric state of the atmosphere. * * * * * linnÆus.[ ] [footnote : for the illustrations and many facts in the life of linnæus we are indebted to the _illustrated tidning_, stockholm.] by c.s. hallberg. at intervals in the history of science, long periods of comparative inertia have attended the death of its more distinguished workers. as time progresses and the number of workers increases, there is a corresponding increase in the number of men whose labors merit distinction in the literature of every language; but as these accessions necessitate in most cases further division of the honors, many names conspicuously identified with modern science fail of their just relative rank, and fade into unmerited obscurity. thus the earlier workers in science, like scheele, liebig, humboldt, and others of that and later periods, have won imperishable fame, to which we all delight to pay homage, while others of more recent times, whose contributions have perhaps been equally valuable for their respective periods, are given stinted recognition of their services, if indeed their names are not quite forgotten. nothing illustrates so clearly the steps in the evolution of science as a review of the relative status of its representatives. as in the political history of the world an epoch like that of the french revolution stands out like a mountain peak, so in the history of science an epoch occurs rather by evolution than revolution, when a hitherto chaotic, heterogeneous mass of knowledge is rapidly given shape and systematized. previous to the seventeenth century an immense mass of facts had accumulated through the labors of investigators working under the baconian philosophy, but these facts had been thrown together in a confused, unsystematic manner. a man of master mind was then needed to grasp the wonders of nature and formulate the existing knowledge of them into a scientific system with a natural basis. such a system was given by linnæus, and so great were its merits that it continues the foundation of all existing systems of classification. charles linnæus was born may , , in a country place named roshult in smaland, near skane, sweden. he was called charles after the well known swedish knight errant, king charles xii., then at the height of his renown. the natural beauty of his native place, with its verdure-clad hills, its stately trees, and sparkling brooks fringed with mosses and flowers, inspired the boy linnæus with a love of nature and a devotion to her teachings which tinged the current of his whole life. he was destined by his parents for the ministry, and in accordance with their wish was sent to the vexio academy ("gymnasium"). here the dull theological studies interfered so much with his study of nature that he would have felt lost but for the sympathy of dr. rothman, one of his teachers, a graduate of harderwyk university, holland, who had been a pupil of boerhaave (the most eminent physician and scientist of his day), and been much impressed by his scientific teachings. [illustration] dr. rothman took a great interest in linnæus, and assured his father that he would prove a great success financially and otherwise as a physician (an occupation whose duties then included a study of all existing sciences). the father was satisfied, but dreaded the effect the announcement of such a career would have on the mother, whose ambition had been to see her son's name among the long list of clergymen of the family who had been ministers to the neighboring church of stentrohult. she finally yielded, and the best possible use was made by linnæus of dr. rothman's tuition. latin, then the mother tongue of all scientists and scholars, he wrote and spoke fluently. at the age of twenty linnæus entered the university of lund, and remained there a year. here he formed the acquaintance of a medical man, a teacher in the university, who opened his home and his library to him, and took him on his botanical excursions and professional visits. some time later, on dr. rothman's advice, linnæus entered the university of upsala, then the most celebrated university of northern europe. his parents were able to spare him but one hundred silver thalers for his expenses. at the end of a year his money was spent, his clothing and shoes were worn out, and he was without prospects of obtaining a scholarship. when things were at their gloomiest he accidentally entered into a discussion with a stranger in the botanical garden, who turned out to be a clergyman scientist named celsius. celsius, while staying at upsala, had conceived the plan of given a botanical description of biblical plants. having learned that linnæus had a herbarium of plants, he took the young man under his protection, and opened up to him his home and library. while studying in this library, his observations regarding the sexes in plants, hitherto in a chaotic state, took form, stimulated by an abstract published in a german journal of vaillant's views, and before the end of the basis of the sexual system had appeared in manuscript. this treatise having been seen by a member of the university faculty, linnæus was invited to fill a temporary vacancy, and lectured with great success therein one and a half years. meanwhile the foundation of the celebrated treatises afterward published on the sexual system of classification and on plant nomenclature had been laid. as in the history of most great men, a seemingly great misfortune proved to be a turning point in his career. the position he had temporarily filled with such credit to himself and profit to the students was claimed by its regular occupant, and, despite the opposition of the faculty, linnæus had to relinquish it. the two subsequent years were spent in botanical investigations under the patronage of various eminent men. during one of these he traveled through lapland to the shores of the polar sea, and the results of this expedition were embodied in his "lapland flora," the first flora founded on the sexual system. he delivered a peripatetic course of lectures, and during one of these he formed the acquaintance of dr. moræus, a pupil of the great boerhaave. dr. moræus took linnæus into partnership with him. here again a seeming misfortune proved to be a great advantage. linnæus fell in love with the eldest daughter of dr. moræus, but was denied her hand until he should graduate in medicine. linnæus, to complete his studies as a physician, then entered the university of harderwyk, holland, the alma mater of his first benefactor, dr. rothman, and of the great boerhaave. after two years' study he was graduated in medicine with high honors. his thesis, "the cause of chills," received special commendation. he visited all the botanical gardens and other scientific institutions for which holland was then renowned. a learned and wealthy burgomaster, gronovius, having read his "systema naturæ" in manuscript, not only defrayed the cost of its publication, but secured him the high honor of an interview with the great boerhaave--an honor for which even the czar peter the great had to beg. boerhaave's interest was at once awakened, and he gave linnæus so strong a recommendation to dr. burman, of amsterdam, that the influence of the scientific circles of the dutch metropolis was exerted in behalf of linnæus, and he was soon offered the position of physician superintendent of a magnificent botanical garden owned by a millionaire horticultural enthusiast, clifford, a director of the dutch east india company. linnæus' financial and scientific future was now secure. publication of his works was insured, and his position afforded him every opportunity for botanical research. after five years' residence in holland, during which he declined several positions of trust, he determined to return to sweden. his fame had become so widespread in western europe that his system was already adopted by scientists and made the basis of lectures at the dutch universities. in the french metropolis he was greatly esteemed, and during a visit thereto he was a highly distinguished guest. [illustration: roshult, sweden, birthplace of linnÆus.] his reception in sweden was rather frigid, and but for the hearty welcome by his family and betrothed he would probably have returned to holland. his _amour propre_ was also doubtless wounded, and he determined to remain and fight his way into the magic circle of the gilt-edged aristocracy which then monopolized all scientific honors in stockholm and the universities. he acquired a great reputation for the treatment of lung disease, and was popularly credited with the ability to cure consumption. this reached the ears of the queen (a sufferer from the disease), who directed one of her councilors to send for linnæus. he soon recognized the name of linnæus as one of great renown on the continent, and at once took him under his protection. the star of linnæus was now in the ascendant. he was soon delegated to various pleasant duties, among which was the delivery of lectures on botany and mineralogy in the "auditorium illustre" at stockholm. he at this time founded the "swedish scientific academy," and was its first president. in he was elected professor of medicine in upsala university, which chair he exchanged for that of botany and the position of director of the botanical garden. this opened up a new era for science in sweden. he who was regarded as the world's greatest botanist abroad had at last been similarly acknowledged in his native land. with the indomitable courage and tact characteristic of the man, he set on foot a gigantic scientific popular educational project. the government, under his direction, established a system of exploring expeditions into the fauna, flora, and mineralogy of the whole swedish peninsula, partly for the purpose of developing the resources of the country, partly in the interest of science, but more especially to interest the mass of the people in scientific research. the vast majority of the people of sweden, like those of other countries, were dominated by fetichic superstitions and absurd notions about plants and vegetables, which were indorsed to a certain extent by popular handbooks devoted more to the dissemination of marvels than facts. a popular clergyman, for instance, stated in a description of the maritime provinces that "certain ducks grew upon trees." the vast stride which was made by the populace in the knowledge of nature was due to these efforts of linnæus, who, in order to further popularize science, established and edited, in conjunction with salvius, a journal devoted to the discussion of natural history. during this period, on the first of may, semi-weekly excursions were made from the university, the public being invited to attend. the people came to these excursions by hundreds, and all classes were represented in them--physicians, apothecaries, preachers, merchants, and mechanics, all joined the procession, which left the university at seven in the morning, to return at eve laden with zoological, botanical, and mineralogical specimens. a man who could thus arouse popular enthusiasm for science a century and a half ago must have been a remarkable genius. trusted students of linnæus were sent on botanical exploring expeditions throughout the world. the high renown in which linnæus was held was shown in the significant title, almost universally bestowed upon him, of "the flower king."--_western druggist._ * * * * * on a method of making the wave length of sodium light the actual and practical standard of length. by albert a. michelson and edward w. morley. the first actual attempt to make the wave length of sodium light a standard of length was made by peirce.[ ] this method involves two distinct measurements: first, that of the angular displacement of the image of a slit by a diffraction grating, and, second, that of the distance between the lines of the grating. both of these are subject to errors due to changes of temperature and to instrumental errors. the results of this work have not as yet been published; but it is not probable that the degree of accuracy attained is much greater than one part in fifty or a hundred thousand. more recently, mr. bell, of the johns hopkins university, using rowland's gratings, has made a determination of the length of the wave of sodium light which is claimed to be accurate to one two hundred thousandth part[ ]. if this claim is justified, it is probably very near the limit of accuracy of which the method admits. a short time before this, another method was proposed by mace de lepinay.[ ] this consists in the calculation of the number of wave lengths between two surfaces of a cube of quartz. besides the spectroscopic observations of talbot's fringes, the method involves the measurement of the index of refraction and of the density of quartz, and it is not surprising that the degree of accuracy attained was only one in fifty thousand. [footnote : nature, xx, , ; this journal, iii, xviii, , .] [footnote : on the absolute wave lengths of light, this journal, iii, xxxiii, , .] [footnote : comptes rendus, cii, , ; journal, de phys., ii, v, , .] several years ago, a method suggested itself which seemed likely to furnish results much more accurate than either of the foregoing, and some preliminary experiments made in june have confirmed the anticipation. the apparatus for observing the interference phenomena is the same as that used in the experiments on the relative motion of the earth and the luminiferous ether. light from the source at s (fig. ), a sodium flame, falls on the plane parallel glass, a, and is divided, part going to the plane mirror, c, and part to the plane mirror, b. these two pencils are returned along _cae_ and _bae_, and the interference of the two is observed in the telescope at e. if the distances, _ac_ and _ab_, are made equal, the plane, c, made parallel with that of the image of b, and the compensating glass, d, interposed, the interference is at once seen. if the adjustment be exact, the whole field will be dark, since one pencil experiences external reflection and the other internal. if now b be moved parallel with itself a measured distance by means of the micrometer screw, the number of alternations of light and darkness is exactly twice the number of wave lengths in the measured distance. thus the determination consists absolutely of a measurement of a length and the counting of a number. the degree of accuracy depends on the number of wave lengths which it is possible to count. fizeau was unable to observe interference when the difference of path amounted to , wave lengths. it seemed probable that with a smaller density of sodium vapor this number might be increased, and the experiment was tried with metallic sodium in an exhausted tube provided with aluminum electrodes. it was found possible to increase this number to more than , . now it is very easy to estimate tenths or even twentieths of a wave length, which implies that it is possible to find the number of wave lengths in a given fixed distance between two planes with an error less than one part in two millions and probably one in ten millions. but the distance corresponding to , wave lengths is roughly a decimeter, and this cannot be determined or reproduced more accurately than say to one part in , . so it would be necessary to increase this distance. this can be done by using the same instrument together with a comparer. the intermediate standard decimeter, lm (fig. ), is put in place of the mirror, b. it consists of a prism of glass one decimeter long with one end, l, plane, and the other slightly convex, so that when it touches the plane, m, newton's rings appear, and these serve to control any change in the distance, lm, which has been previously determined in wave lengths. the end, l, is now adjusted so that colored fringes appear in white light. these can be measured to within one-twentieth of a wave length, and probably to within one-fiftieth. the piece, lm, is then moved forward till the fringes again appear at m. then the refractometer is moved in the same direction till the fringes appear again at l, and so on till the whole meter has been stepped off. supposing that in this operation the error in the setting of the fringes is always in the same direction, the whole error in stepping off the meter would be one part in two millions. by repetition this could of course be reduced. a microscope rigidly attached to the carriage holding the piece, lm, would serve to compare, and a diamond attached to the same piece would be used to produce copies. all measurements would be made with the apparatus surrounded by melting ice, so that no temperature corrections would be required. probably there would be considerable difficulty in actually counting , wave lengths, but this can be avoided by first counting the wave lengths and fractions in a length of one millimeter and using this to step off a centimeter. this will give the nearest whole number of wave lengths, and the fractions may be observed directly. the centimeter is then used in the same way to step off a decimeter, which again determines the nearest whole number, the fraction being observed directly as before. the fractions are determined as follows: the fringes observed in the refractometer under the conditions above mentioned can readily be shown to be concentric circles. the center has the minimum intensity when the difference in the distances, ab, ac, is an exact number of wave lengths. the diameters of the consecutive circles vary as the square roots of the corresponding number of waves. therefore, if x is the fraction of a wave length to be determined, and y the diameter of the first dark ring, d being the diameter of the ring corresponding to one wave length, then x = y²/d². [illustration: ----- +---+ |c | | | | | | | |+-------------------------+ | | || | | | || | | | |+-------------------------+ l | | | . | | | m | +---+ | ______ | +-------------| |---+ | /\ /\ | +-----------| __|-+ | _ a|/ / / / | | | b | | | | | s----------/\/__d/ / | | | | | | | | | / /| / /-----| |-----------|-| ||||||||||| | | \/ | | | | | | | | | _|_ | | | | | | |_| | : | | +-----------|___|----+ | m e| : | +-----------------------+ | : | |_ _| . u ] there is a slight difficulty to be noted in consequence of the fact that there are two series of waves in sodium light. the result of this superposition of these is that as the difference of path increases, the interference becomes less distinct and finally disappears, reappears, and has a maximum of distinctness again, when the difference of path is an exact multiple of both wave lengths. thus there is an alternation of distinct interference fringes with uniform illumination. if the length to be measured, the centimeter for instance, is such that the interference does not fall exactly at the maximum--to one side by, say, one-tenth the distance between two maxima, there would be an error of one-twentieth of a wave length requiring an arithmetical correction. among other substances tried in the preliminary experiments were thallium, lithium, and hydrogen. all of these gave interference up to fifty to one hundred thousand wave lengths, and could therefore all be used as checks on the determination with sodium. it may be noted that in case of the red hydrogen line, the interference phenomena disappeared at about , wave lengths, and again at about , wave lengths; so that the red hydrogen line must be a double line with the components about one-sixtieth as distant as the sodium lines.--_amer. jour. science._ * * * * * [rural new yorker] cold storage for potatoes. upon this subject i am able to speak with the freedom habitually enjoyed by some voluminous agricultural writers--my imagination will not be hampered by my knowledge. in debatable climates, like ohio, illinois, kansas and southward, it is conceded that a great point would be gained by the discovery of some plan--not too expensive--that would make it safe to put away potatoes in the summer, as soon as ripe, so that they would go through the winter without sprouting and preserve their eating qualities till potatoes come again. as it is, digging must be deferred till late, for fear of rot; the fields of early varieties grow up with weeds after they are "laid by." in the spring a long interregnum is left between old potatoes fit to eat and the new crop, and the seed stock of the country loses much of its vigor through sprouting in cellars and pits. most farmers have had occasion to notice the difference between the yield from crisp, unsprouted seed potatoes and that from the wilted, sprouted tubers so often used. some years ago professor beal made a test of this difference. i speak from recollection, but think i am right in saying that, according to the published account which i saw, he found one sprouting of seed potatoes lowered the yield per cent.; each additional sprouting still further reduced the crop, till finally there was no yield at all. even a per cent. shrinkage in all that portion of the annual potato crop grown from sprouted seed would result in an aggregate loss of millions of bushels. the question how to store potatoes and not have them sprout i have seen answered in the papers by recommending a "cold" cellar, of about degrees temperature. if there are cellars that are cold in warm weather, without the use of some artificial process, i have not seen them. the temperature of well water is about degrees only, and anybody knows how much colder a well is than a cellar. but the greatest difficulty comes in from the fact that potatoes are such a prolific source of heat in themselves. if a degree cellar could be found and be filled with potatoes, the temperature would at once begin to rise, and the later in the season, the faster it would go up. i repeat that a cellar filled with potatoes will have a much higher temperature than the same cellar would have if empty. this i have learned as nimbus learned tobacco growing--"by 'sposure." i hope i won't be asked "why." i don't know. the reason is unimportant. the remedy is the thing. the only help for it that i know of is to give the cellar plenty of ventilation, put the potatoes in as clean as possible, and then shovel them over every month or two. this will keep the sprouting tendency in check very largely; but it won't make it practicable to begin storing potatoes in july or cause them to keep in good flavor till june. several years ago i placed some barrels of early ohio potatoes in the kansas city cold storage warehouses from march till july. they were kept in a temperature of degrees, and came out crisp and very little sprouted. the plan of this structure was very simple: a three-story brick building so lined with matched lumber and tarred paper as to make three air-spaces around the wall. in the top story was a great bulk of ice, which was freely accessible to the air that, when cooled, passed through ducts to the different "cool rooms." the results were satisfactory, but the system seemed too expensive for potatoes. i have wondered whether it was necessary for potatoes to be kept as cold as degrees. would not a current of air passing through pipes showered with well water keep them cold enough? wine vaults, i believe, are sometimes cooled by air currents forced through a cold water spray. if the air blast of well water temperature would be sufficient, the apparatus for producing it would be comparatively inexpensive--or at least much cheaper than those plans of cold storage where ice is stored in quantity over the cool room. however, any process that could be devised would probably be unprofitable to the small cropper, and the larger the business done, the less the cost per bushel. if it should be found that individual operators could not reach such an improvement on a profitable scale, why could not several of them pool their issues sufficiently to build, jointly, a potato elevator? there are at least , bushels of potatoes held in store by farmers within three miles of where i live. it seems to me there would be many advantages and economies in having that large stock under one roof, one insurance, one management; on a side track where they could be loaded in any weather or state of the roads, besides the great item that the temperature could be controlled, by artificial means, in one large building much cheaper than in several small ones. edwin taylor. edwardsville, kans. * * * * * [knowledge.] a fivefold comet. the figure illustrating this article is taken from _l'astronomie_, and represents the remarkable southern comet of january, , as drawn on successive days by mr. finlay, of cape town. the comet was first seen by a farmer and a fisherman of blauwberg, near cape town, on the night of january - . the same night it was seen at the cordoba observatory by m. thome. on the next mr. todd discovered it independently at the adelaide observatory, and watched it till the th. on the d mr. finlay detected the comet, and was able to watch it till the th. at rio de janeiro m. cruls observed it from the d to the th; and at windsor, new south wales, mr. tebbutt observed the comet on the th and th. moonlight interfered with further observations. the comet's appearance was remarkable. its tail, long and straight, extended over an arc of degrees, but there was no appreciable condensation which could be called the comet's head. the long train of light, described as nearly equal in brightness to the magellanic clouds, seemed to be simply cut off at that end where in most comets a nucleus and coma are shown. this comet has helped to throw light on one of the most perplexing puzzles which those most perplexing of all the heavenly bodies, comets, have presented to astronomers. in the year a comet was seen in the southern skies which attracted very little notice at the time, and would probably have been little thought of since had not attention been directed to it by the appearance and behavior of certain comets seen during the last half century. visible for about three weeks, and discovered after it had already passed the point of its nearest approach to the sun, the comet of was not observed so satisfactorily that its orbit could be precisely determined. in fact, two entirely different orbits would satisfy the observations fairly, though one only could be regarded as satisfying them well. this orbit, however, was so remarkable that astronomers were led to prefer the other, less satisfactory though it was, in explaining the observed motions of the comet. for the orbit which best explained the comet's movements carried the comet so close to the sun as actually to graze his visible surface. moreover, there was this remarkable, and, indeed, absolutely unique peculiarity about the orbit thus assigned: the comet (whose period of revolution was to be measured by hundreds of years) actually passed through the whole of that part of its course during which it was north of our earth's orbit plane in less than two hours and a half! though this part of its course is a half circuit around the sun, so far as direction (not distance of travel) is concerned. that comet, when at its nearest to the sun, was traveling at the rate of about miles per second. it passed through regions near the sun's surface commonly supposed to be occupied by atmospheric matter. now, had the comet been so far checked in its swift rush through those regions as to lose one thousandth part of its velocity, it would have returned in less than a year. but the way in which the comet retreated showed that nothing of this sort was to be expected. i am not aware, indeed, that any anticipations were ever suggested in regard to the return of the comet of to our neighborhood. it was not till the time of halley's comet, , that modern astronomy began to consider the question of the possibly periodic character of cometic motions with attention. (for my own part, i reject as altogether improbable the statement of seneca that the ancient chaldean astronomers could calculate the return of comets.) the comet of , called newton's, was the very first whose orbital motions were dealt with on the principles of newtonian astronomy, and halley's was the first whose periodic character was recognized. in another comet came up from the south, and presently returned thither. it was, indeed, only seen during its return, having, like the comet of , been only discovered a day or two after perihelion passage. astronomers soon began to notice a curious resemblance between the orbits of the two comets. remembering the comparative roughness of the observations made in , it may be said that the two comets moved in the same orbit, so far as could be judged from observation. the comet of came along a path inclined at apparently the same angle to the earth's orbit plane, crossed that plane ascendingly at appreciably the same point, swept round in about two hours and a half that part of its angular circuit which lay north of the earth's orbit plane, and, crossing that plane descendingly at the same point as the comet of , passed along appreciably the same course toward the southern stellar regions! the close resemblance of two paths, each so strikingly remarkable in itself, could not well be regarded as a mere accidental coincidence. [illustration: the constellations, though unnamed, can readily be identified, when it is noted that the comet's course, as here represented, began in the constellation of the crane.] however, at that time no very special attention was directed to the resemblance between the paths of the comets of and . it was not regarded as anything very new or striking that a comet should return after making a wide excursion round the sun; and those who noticed that the two comets really had traversed appreciably the same path around the immediate neighborhood of the sun, simply concluded that the comet of had come back in , after years, and not necessarily for the first time. it must be noticed, however, before leaving this part of the record, that the comet of was suspected of behaving in a rather strange way when near the sun. for the first observation, made rather roughly, indeed, with a sextant, by a man who had no idea of the interest his observation might afterward have, could not be reconciled by mathematicians (including the well-known mathematician, benjamin pierce) with the movement of the comet as subsequently observed. it seemed as though when in the sun's neighborhood the comet had undergone some disturbance, possibly internal, which had in slight degree affected its subsequent career. according to some calculations, the comet of seemed to have a period of about thirty-five years, which accorded well with the idea that it was the comet of , returned after five circuits. nor was it deemed at all surprising that the comet, conspicuous though it is, had not been detected in , , , and , for its path would carry it where it would be very apt to escape notice except in the southern hemisphere, and even there it might quite readily be missed. the appearance of the comet of corresponded well with that of the comet of . each was remarkable for its extremely long tail and for the comparative insignificance of its head. in the northern skies, indeed, the comet of showed a very straight tail, and it is usually depicted in that way, whereas the comet of had a tail showing curvature. but pictures of the comet of , as seen in the southern hemisphere, show it with a curved tail, and also the tail appeared forked toward the end during that part of the comet's career. however, the best observations, and the calculations based on them, seemed to show that the period of the comet of could not be less than years. astronomers were rather startled, therefore, when, in , a comet appeared in the southern skies which traversed appreciably the same course as the comets of and . when i was in australia, in , a few months after the great comet had passed out of view, i met several persons who had seen both the comet of that year and the comet of . they all agreed in saying that the resemblance between the two comets was very close. like the comet of , that of had a singularly long tail, and both comets were remarkable for the smallness and dimness of their heads. one observer told me that at times the head of the comet of could barely be discerned. like the comets of and , the comet of grazed close past the sun's surface. like them, it was but about two hours and a half north of the earth's orbit place. had it only resembled the other two in these remarkable characteristics, the coincidence would have been remarkable. but of course the real evidence by which the association between the comets was shown was of a more decisive kind. it was not in general character only, but in details, that the path of the comet of resembled those on which the other two comets had traveled. its path had almost exactly the same slant to the earth's orbit plane as theirs, crossed that plane ascendingly and descendingly at almost exactly the same points, and made its nearest approach to the sun at very nearly the same place. to the astronomer such evidence is decisive. mr. hind, the superintendent of the "nautical almanac," and as sound and cautious a student of cometic astronomy as any man living, remarked, so soon as the resemblance of these comets' paths had been ascertained, that if it were merely accidental, the case was most unusual; nay, it might be described as unique. and, be it noticed, he was referring only to the resemblance between the comets of and . had he recalled at the time the comet of , and its closely similar orbit, he would have admitted that the double coincidence could not possibly be merely casual. but this was by no means the end of the matter. indeed, thus far, although the circumstances were striking, there was nothing to prevent astronomers from interpreting them as other cases of coincident, or nearly coincident, cometic paths had been interpreted. hind and others, myself included, inferred that the comets of , , and were simply one and the same comet, whose return in probably followed the return in after a single revolution. in , however, two years and a half after the appearance of the comet of , another comet came up from the south, which followed in the sun's neighborhood almost the same course as the comets of , , and . the path it followed was not quite so close to those followed by the other three as these had been to each other, but yet was far too close to indicate possibly a mere casual resemblance; on the contrary, the resemblance in regard to shape, slope, and those peculiarities which render this family of comets unique in the cometary system, was of the closest and most striking kind. many will remember the startling ideas which were suggested, by professor piazzi smyth respecting the portentous significance of the comet of . he regarded it as confirming the great pyramid's teaching (according to the views of orthodox pyramidalists) respecting the approaching end of the christian dispensation. it was seen under very remarkable circumstances, blazing close by the sun, within a fortnight or three weeks of the precise date which had been announced as marking that critical epoch in the history of the earth. moreover, even viewing the matter from a scientific standpoint, professor smyth (who, outside his pyramidal paradoxes, is an astronomer of well deserved repute) could recognize sufficient reason for regarding the comet as portentous. many others, indeed, both in america and in europe, shared his opinion in this respect. a very slight retardation of the course of the comet of , during its passage close by the surface of the sun, would have sufficed to alter its period of revolution from the thirty-seven years assigned on the supposition of its identity with the comet of to the two and a half years indicated by its apparent return in , and if this had occurred in , a similar interruption in would have caused its return in less than two and a half years. thus, circling in an ever narrowing (or rather shortening) orbit, it would presently, within a quarter of a century or so perhaps, have become so far entangled among the atmospheric matter around the sun that it would have been unable to resist absolute absorption. what the consequences to the solar system might have been, none ventured to suggest. newton had expressed his belief that the effects of such absorption would be disastrous, but the physicists of the nineteenth century, better acquainted with the laws associating heat and motion, were not so despondent. only professor smyth seems to have felt assured (not being despondent, but confident) that the comet portended, in a very decisive way, the beginning of the end. however, we were all mistaken. the comet of retreated on such a course, and with such variation of velocity, as to show that its real period must be measured, not by months, as had been supposed, nor even by years, but by centuries. probably it will not return till or years have passed. had this not been proved, we might have been not a little perplexed by the return of apparently the same comet in this present year. a comet was discovered in the south early in january, whose course, dealt with by professor kruger, one of the most zealous of our comet calculators, is found to be partially identical with that of the four remarkable comets we have been considering. astronomers have not been moved by this new visitant on the well-worn track as we were by the arrival of the comet of , or as we should have been if either the comet of had never been seen or its path had not been shown to be so wide ranging. whatever the comet of the present year may be, it was not the comet of returned. no one even supposes that it was the comet of , or , or . nevertheless, rightly apprehended, the appearance of a comet traveling on appreciably the same track as those four other comets is of extreme interest, and indeed practically decisive as to the interpretation we must place on these repeated coincidences. observe, we are absolutely certain that the five comets are associated together in some way; but we are as absolutely certain that they are not one and the same comet which had traveled along the same track and returned after a certain number of circuits. we need not trouble ourselves with the question whether two or more of the comets may not have been in reality one and the same body at different returns. it suffices that they all five were not one; since we deduce precisely the same conclusion whether we regard the five as in reality but four or three or two. but it may be mentioned in passing as appearing altogether more probable, when all the evidence is considered, that there were no fewer than five distinct comets, all traveling on what was practically the selfsame track when in the neighborhood of the sun. there can be but one interpretation of this remarkable fact--a fact really proved, be it noticed (as i and others have maintained since the retreat of the comet of ), independently of the evidence supplied by the great southern comet of the present year. these comets must all originally have been one comet, though now they are distinct bodies. for there is no reasonable way (indeed, no possible way) of imagining the separate formation of two or more comets at different times which should thereafter travel in the same path. no theory of the origin of comets ever suggested, none even which can be imagined, could account for such a peculiarity. whereas, on the other hand, we have direct evidence showing how a comet, originally single, may be transformed into two or more comets traveling on the same, or nearly the same, track. the comet called biela's, which had circuited as a single comet up to the year (during a period of unknown duration in the past--probably during millions of years), divided then into two, and has since broken up into so many parts that each cometic fragment is separately undiscernible. the two comets into which biela's divided, in , were watched long enough to show that had their separate existence continued (visibly), they would have been found, in the fullness of time, traveling at distances very far apart, though on nearly the same orbit. the distance between them, which in had increased only to about a quarter of a million of miles, had in increased to five times that space. probably a few thousands of years would have sufficed to set these comets so far apart (owing to some slight difference of velocity, initiated at the moment of their separation) that when one would have been at its nearest to the sun, the other would have been at its farthest from him. if we could now discern the separate fragments of the comet, we should doubtless recognize a process in progress by which, in the course of many centuries, the separate cometic bodies will be disseminated all round the common orbit. we know, further, that already such a process has been at work on portions removed from the comet many centuries ago, for as our earth passes through the track of this comet she encounters millions of meteoric bodies which are traveling in the comet's orbit, and once formed part of the substance of a comet doubtless much more distinguished in appearance than biela's. there can be little doubt that this is the true explanation of the origin of that family of comets, five of whose members returned to the neighborhood of the sun (possibly their parent) in the years , , , , and .[ ] [footnote : it may be interesting to compare the orbital elements of the five comets above dealt with. they may be presented as follows; but it should be noticed that the determinations must be regarded as rough in the case of comets i. and v., as the observations were insufficient for exact determination of the elements: ----------------+---------+------------+------------+------------+------- | i. | ii. | iii. | iv. | v. +---------+------------+------------+------------+------- | . | . | . | . | . perih. passage.| feb. | feb. | jan. | sep. |jan. log. per. dist.| . | . | . | . | . long. per. | ° ' | ° ' "| ° ' "| ° ' "| ° ' long. node. | ° '| ° ' "| ° ' "| ° ' "| ° ' inclination. | ° '| ° ' "| ° ' "| ° ' "| ° ' eccentricity. | . | . | . | . | ...... calculator. |henderson| plantamour | meyer | kreutz | finlay ----------------+---------+------------+------------+------------+------- ] but it is not merely as thus explaining what had been a most perplexing problem that i have dealt with the evidence supplied by the practical identity of these five comets' orbits. when once we recognize that this, and this only, can be the explanation of the associated group of five comets, we perceive that very interesting and important light has been thrown on the subject of comets generally. to begin with: what an amazing comet that must have been from which these five, and we know not how many more, were formed by disaggregative processes--probably by the divellent action of repulsive forces exerted by the sun! those who remember the comets of and as they appeared when at their full splendor will be able to imagine how noble an appearance a comet would present which was formed of these combined together in one. but the comet of was described by all who saw it in the southern hemisphere as most remarkable in appearance, despite the faintness of its head. the great southern comet of the present year was a striking object in the skies, though it showed the same weakness about the head. that of was probably as remarkable in appearance as even the comet of . a comet formed by combining all these together would certainly surpass in magnificence all the comets ever observed by astronomers. and then, what enormous periods of time must have been required to distribute the fragments of a single comet so widely that one would be found returning to its perihelion more than two centuries after another! when i spoke of one member of the biela group being in aphelion when another would be in perihelion, i was speaking of a difference of only three and one-third years in time; and even that would require thousands of years. but the scattered cometic bodies which returned to the sun's neighborhood in and speak probably of millions of years which have passed since first this comet was formed. it would be a matter of curious inquiry to determine what may have been the condition of our sun, what even his volume, at that remote epoch in history. * * * * * the isolation of fluorine. the element fluorine has at last been successfully isolated, and its chief chemical and physical properties determined. many chemists, notably faraday, gore, pflaunder, and brauner, have endeavored to prepare this element in the free state, but all attempts have hitherto proved futile. m. moissau, after a long series of researches with the fluorides of phosphorus, and the highly poisonous arsenic trifluoride, has finally been able to liberate fluorine in the gaseous state from anhydrous hydrofluoric acid by electrolysis. this acid in the pure state is not an electrolyte, but when potassium fluoride is dissolved in it, a current from ninety bunsen elements decomposes it, evolving hydrogen from the negative and fluoride from the positive electrode. [illustration: (+) (-) | | | | __/_|_\_a __/_|_\_a | | | | | | |____|____| |____|____| | | | | | | _____| | | | | |_____ / ---- | | | | -----\ // | | | | | | \\ || f |===|===| |===|===| h || || |- -|- -| |- -|- -| || || | - | - | | - | - | || || |- -|- - \_________/ - -|- -| || || | - | - - - - - - - - - | - | || // \___________________________/ \\ ] the apparatus employed in this process is constructed of platinum, and is made in the form of a u tube, as shown in the accompanying illustration, with fluorspar stoppers, through which the battery terminals, made of platinum iridium alloy, are led. the gas is liberated at about the rate of two liters per hour, and has very powerful chemical properties. it smells somewhat like hypochlorous acid, etches dry glass, and decomposes water, liberating ozone, and forming hydrofluoric acid. the non-metallic elements, with the exception of chlorine, oxygen, nitrogen, and carbon, combine directly with it, evolving in most cases both light and heat. it combines with hydrogen, even in the dark, without the addition of any external energy, and converts most metals into their fluorides. gold and platinum are not attacked in the cold, but when gently heated are easily corroded. mercury readily dissolves the gas, forming the protochloride; iron wire also completely absorbs the gas, while powdered antimony and lead take fire in it. it is necessary in the electrolysis of the liquid hydrofluoric acid to cool the electrolytic cell by means of methyl chloride to - ° c. fluorine appears to thus fully confirm the predictions which have been made by chemists concerning its properties. it is by far the, most energetic of all the known elements, and its position in the halogen series is established by its property of not liberating iodine from the iodides of potassium, mercury, and lead, and also of setting free chlorine from potassium chloride. with iodine it appears to form a fluoride. no compound with oxygen has yet been obtained.--_industries._ * * * * * an apparatus for preparing sulphurous, carbonic, and phosphoric anhydrides. by h.n. warren, research analyst. having had occasion to prepare a quantity of sulphurous anhydride, for the purpose of reducing chromates previous to their analysis, i made use of the following apparatus, as represented in the accompanying figure. it consists of a glass vessel, a, provided with three tubulars, otherwise resembling a large wolff bottle, the large tube, b, being provided with a stopper for the purpose of introducing pieces of sulphur from time to time into the small dish, c, intended for its reception, and fed with air by means of the delivery tube, d, thus allowing the stream of gas caused by the consumption of the sulphur to escape by means of the exit tube, e, to the vessel desired to receive it. [illustration] in using the apparatus the sulphur is first kindled by introducing a red hot wire through the tube, b, and replacing the stopper that has been momentarily removed for the introduction of the same. a slight blast is now maintained from the bellows that are in connection with the pipe, d, until the whole of the sulphur is thoroughly kindled, when a somewhat more powerful blast may be applied. when the apparatus above described is in full working order, from to lb. of sodium carbonate may be converted into sodium sulphite in less than half an hour, or several gallons of water saturated. i have also on connecting the apparatus with a powerful refrigerator obtained in a short time a large quantity of liquid so . it will be found advantageous, however, during the preparation of sulphurous anhydride, to employ a layer of water covering the bottom of the vessel to about inch in depth. carbonic anhydride and phosphoric anhydride may also be readily obtained in any desired quantity by slight alteration; but in case of phosphorus the air must be allowed to enter only gently, since a rapid current would at all times determine the fracture of the vessel.--_chem. news_. * * * * * the arrangement of atoms in space in organic molecules.[ ] [footnote : ueber die raumliche anordnung der atome in organischen molekulen, and ihre bestimmung in geometrisch-isomeren ungesattigten verbindungen. von johannes wislicenus.--abhandlungen der mathemalisch-physischen klasse der konigl. sachsischen gesellschaft der wissenechaften. band xiv., no. .] the expression "chemical structure," as commonly used by chemists, has, as is well known, nothing to do with the arrangement of atoms in space. the structural formula does not profess to represent spatial relations, but simply the connections which, after a careful study of the transformations and modes of formation of the compound represented, are believed to exist between the atoms. nevertheless, although we do not commonly consider the question of space relations, it is clear that atoms must have some definite positions in space in the molecules, and the only reason why we do not represent these positions is because we know practically nothing about them. the most definite suggestion concerning space relations of atoms which has been made is that of le bel and van't hoff. the well known hypothesis of these authors was put forward to account for a certain kind of so-called physical isomerism which shows itself in the action of substances upon polarized light. since this hypothesis was proposed, the number of cases of "abnormal isomerism," that is to say, of cases of isomerism which cannot be accounted for by the commonly accepted method of explaining structure, has increased to a considerable extent, and the necessity for some new hypothesis, or for some modification of the old ones, has come to be pretty generally recognized. among the cases of isomerism which it is at least difficult to explain by the aid of the prevailing views are those of maleic and fumaric acids; citraconic and mesaconic acids; certain halogen derivatives of crotonic acid and of cinnamic acid; and coumaric and coumarinic acids. more than one hypothesis has been proposed to account for these cases of isomerism, but no one has shown itself to be entirely satisfactory. quite recently johannes wislicenus, professor of chemistry in the university of liepsic, has made what has the appearance of being an important contribution toward the solution of the problem referred to. the author shows that many of the facts known in regard to the relations between maleic and fumaric acids, and the other substances which furnish examples of "abnormal isomerism," may be explained by the aid of an extension of the le bel-van't hoff hypothesis. it is difficult without the aid of models to give a clear idea concerning the hypothesis of wislicenus, but some idea of it may be gained from the following. if we suppose a carbon atom to exert its affinities in the directions of the solid angles of a tetrahedron, as is done in the le bel-van't hoff hypothesis, then, when two carbon atoms unite, as in ethane, the union will be between two solid angles of two tetrahedrons. if the two carbon atoms unite by the ethylene kind of union, the union will be along a line corresponding to one of the edges of each tetrahedron. in the former case, in which single union exists, the two parts of the molecule represented by the two tetrahedrons can be supposed to be capable of revolving around an axis either in the same direction or in opposite directions. this axis corresponds to the straight line joining the two carbon atoms. in the case in which double union exists no such revolution is possible. again, if, by addition to an unsaturated compound like ethylene, a saturated compound is formed, the kind of union between the carbon atoms is changed, and the possibility of revolution of the two parts of the compound is given. whether such revolution take place or not will be determined largely by the structure of the compound. the tendency will be for those parts of the molecule which have the greatest specific affinity for one another to take those positions in which they are nearest to one another. thus, suppose that chlorine is added to ethylene. by following the change on the model, it is seen that in the resulting figure the two chlorine atoms in ethylene chloride are situated at angles of the two tetrahedrons which are nearest each other. but chlorine has a stronger affinity for hydrogen than it has for chlorine, and therefore each chlorine atom would tend to get as near a hydrogen atom as possible. this involves a partial revolution of the two tetrahedrons in opposite directions around their common axis. so also hydrogen would tend to take a position as near as possible to hydroxyl and to carboxyl, while hydroxyl would avoid hydroxyl, and carboxyl would avoid carboxyl. these views are suggested as a result of a careful application of the original le bel-van't hoff hypothesis, and are, of course, of little value unless they can be shown to be in accordance with the facts. the chief merit of the work of wislicenus consists in the fact that he has shown that a large number of phenomena which have been observed in the study of such cases of isomerism as were mentioned above find a ready explanation in terms of the new hypothesis, whereas for most of these phenomena no explanation whatever has thus far been presented. the most marked case presented is that of maleic and fumaric acids. one by one, the author discusses the transformations of these acids and their substitution products, and becomes to this conclusion: "there is not to my knowledge a single fact known in regard to the relations between fumaric and maleic acids which is not explained by the aid of the above geometrical considerations, not one which does not clearly support the new hypothesis." among the facts which he discusses in the light of the hypothesis are these: the formation of fumaric and maleic acids from malic acid; the quantitative transformation of maleic into fumaric acid by contact with strong acids; the transformation of the ethereal salts of maleic acid into those of fumaric acid by the action of a minute quantity of free iodine; the formation of brommaleic acid and hydrobromic acid from the dibromsuccinic acid formed by the addition of two bromine atoms to fumaric acid; the formation of dibromsuccinic acid from brommaleic acid and of isodibromsuccinic acid from bromfumaric acid by the action of fuming hydrobromic acid; the conversion of brommaleic acid into fumaric and then into succinic acid by the action of sodium amalgam; the formation of one and the same tribromsuccinic acid by the action of bromine on brommaleic and on bromfumaric acid; and finally, the conversion of maleic into inactive tartaric acid, and of fumaric into racemic acid by potassium permanganate. all these facts are shown to find a ready explanation by the aid of the new hypothesis. further, it is shown that the decompositions of the salts of certain halogen derivatives of organic acids, which give up halogen salt and carbon dioxide, as well as the formation of lactones and of anhydrides of dibasic acids, are in perfect harmony with the hypothesis. but the only way to get a clear conception in regard to the mass of material which the author has brought together and which he has shown to support his hypothesis is by a careful study of the original paper, and the object of this notice is mainly to call the attention of american chemists to it. as to the question what value to attach to the speculations which wislicenus has brought to our notice, it is difficult to give any but a general answer. no one can well have a greater fear of mere speculation, which is indulged in independently of the facts, than the writer of this notice. great harm has been done chemistry, and probably every other branch of knowledge, by unwarranted speculation, and every one who has looked into the matter knows how extremely difficult it is to emancipate one's self from the influence of a plausible hypothesis, even when it can be shown that it is not in accordance with the facts. it behooves every one, therefore, before accepting a new hypothesis, no matter how fascinating it may appear at first sight, to look carefully into the facts, and to endeavor to determine independently whether it is well founded or not. on the other hand, there is some danger to be apprehended from a tendency, sometimes observed, to denounce everything speculative, no matter how broad the basis of facts upon which it rests may be. without legitimate speculation, it is clear that there could be no great progress in any subject. as far as the hypothesis under consideration is concerned, the writer is firmly of the opinion that it is likely to prove of great value in dealing with a large number of chemical facts, and that, as it suggests many lines of research, it will undoubtedly in the course of a few years exert a profound influence on chemistry. whether the evidence which will be accumulated will or will not confirm the view that the tetrahedron form is characteristic of the simplest molecules of carbon compounds is not the most important question to be asked under the circumstances. we should rather ask whether the testing of the hypothesis is or is not likely to bring us nearer to the truth. it is a proposition that admits of no denial that a hypothesis which can be tested by experiment, and which suggests lines of work and stimulates workers to follow them, is a gain to science, no matter what the ultimate fate of the hypothesis may be.--_amer. chem. jour._ * * * * * great warmth in paper. it should be thoroughly understood by all that any common paper, coarse wrapping paper, new or old newspapers, etc., are admirable to keep out cold or keep in warmth. the blood of _all_ domestic animals, as well as of human beings, _must_ be always kept very near degrees, just as much in winter as in summer. and this heat always comes from _within_ the body, whenever the atmosphere is not above degrees temperature. so long as the air is cooler than this, the heat produced inside the body is escaping. heat seeks a level. if there is more in one of two bodies or substances side by side, the heat will pass from the warmer into the colder, until they are both of the same temperature. moving air carries away vastly more heat than still air. the thin film of air next to the body soon gets warm from it. but if that air is moved along, slowly or swiftly, by a breeze, be it ever so gentle, new cooler air takes its place, and abstracts more heat from the body. anything that keeps the air next to the bodies of men and of animals from moving, checks the escape of heat. the thinnest paper serves to keep the air quiet. a newspaper laid on a bed acts much as a coverlid to keep a film or layer of air quiet, and thus less heat escapes from the bodies of the sleepers. if paper is pasted up over the cracks of a house, or of a barn or stable, or under the joists of a house floor, it has just the same effect. every person who keeps animals will find it a wonderful and paying protection to them, to put against the walls one, two, three, or more layers of newspapers during cold weather. if a person in riding finds his garments too cool, a newspaper placed under the coat or vest, or under or over the trousers, even if only on the side next the wind, will do a great deal to check the outflow of heat, and keep him warm. two or three thicknesses of newspaper crumpled a little, and put under the coat or overcoat, are almost as effective in keeping in warmth as an extra garment. a slight crumpling keeps them a little separate, and makes additional thin layers of air. further: heat does not pass through films of _still_ air. fibrous woolens, furs, loosely woven cotton, down, and the like, contain a great deal of air _confined_ in the meshes, and are therefore excellent conservers of heat. double walls of stone, brick, or wood, or even of wall or roofing paper, double glass, double layers of anything that will have thin layers of still air between them, prevent the escape of heat greatly. * * * * * the scientific american architects and builders edition. $ . a year. single copies, cts. this is a special edition of the scientific american, issued monthly--on the first day of the month. each number contains about forty large quarto pages, equal to about two hundred ordinary book pages, forming, practically, a large and splendid magazine of architecture, richly adorned with _elegant plates in colors_ and with fine engravings, illustrating the most interesting examples of modern architectural construction and allied subjects. a special feature is the presentation in each number of a variety of the latest and best plans for private residences, city and country, including those of very moderate cost as well as the more expensive. drawings in perspective and in color are given, together with full plans, specifications, costs, bills of estimate, and sheets of details. no other building paper contains so many plans, details, and specifications regularly presented as the scientific american. hundreds of dwellings have already been erected on the various plans we have issued during the past year, and many others are in process of construction. architects, builders, and owners will find this work valuable in furnishing fresh and useful suggestions. all who contemplate building or improving homes, or erecting structures of any kind, have before them in this work an almost _endless series of the latest and best examples_ from which to make selections, thus saving time and money. many other subjects, including sewerage, piping, lighting, warming, ventilating, decorating, laying out of grounds, etc., are illustrated. an extensive compendium of manufacturers' announcements is also given, in which the most reliable and approved building materials, goods, machines, tools, and appliances are described and illustrated, with addresses of the makers, etc. the fullness, richness, cheapness, and convenience of this work have won for it the largest circulation of any architectural publication in the world. munn & co., publishers, broadway, new york. a catalogue of valuable books on architecture, building, carpentry, masonry, heating, warming, lighting, ventilation, and all branches of industry pertaining to the art of building, is supplied free of charge, sent to any address. * * * * * building plans and specifications. in connection with the publication of the building edition of the scientific american, messrs. munn & co. furnish plans and specifications for buildings of every kind, including churches, schools, stores, dwellings, carriage houses, barns, etc. in this work they are assisted by able and experienced architects. full plans, details, and specifications for the various buildings illustrated in this paper can be supplied. those who contemplate building, or who wish to alter, improve, extend, or add to existing buildings, whether wings, porches, bay windows, or attic rooms, are invited to communicate with the undersigned. our work extends to all parts of the country. estimates, plans, and drawings promptly prepared. terms moderate. address munn & co., broadway, new york. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . stitched in paper, or $ . bound in stiff covers. combined rates.--one copy of scientific american and 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address munn & co., broadway, new york. branch office, and f st., washington, d.c. [illustration: issue title] the new york scientific american a weekly journal of practical information, art, science, mechanics, chemistry, and manufactures. new york, september , . * * * * * scientific american _published weekly at_ _fulton street_, (_sun building_,) _new york_. by munn & company. rufus porter, editor. terms.--$ a year--$ in advance, and the remainder in months. [symbol: right index] _see advertisement on last page_. * * * * * contents. nature's image of washington the viol seraphine* an eclipse in arabia giving credit the bowie knife and its inventor forests and streams prussian music philosophy polite preaching pure air the deerfield (n. h.) phenomena extraordinary instance of gambling gen. taylor's patriotism the columbian magazine a mountain in labor the pope's will improved railroad sageisms as good as cash how very hot it is california farming diversification of language "keep that testament in your vest pocket, over your heart." temperance in the army modes of raising ponderous articles information to persons having business to transact at the patent office the regulator(?)* a remarkable mineral spring cool forethought it may be so howe's sewing machine steering apparatus electro-magnetic boat improvement in boats casting iron cannon by a galvanic process new shingle machine improvement in blacksmiths forges improved fire engine a simple cheese-press* cast iron roofing the new and wonderful pavement to render shingles durable best plan of a barn robert fulton introduction to volume ii advantage of low fares avalon railroad iron the magnetic telegraph advertising in london deerfield bridge information wanted railroad intelligence arrival of the cambria the mexican war trade to santa fe the scientific american--subscriptions the harbor of havana* a very long nose sol. smith a profitable hoax reforming wrong side up* importance of humility the eureka: or journal of the national association of inventors advertisements the ball of the bears all is not gold that glitters painting in imitation of rose-wood india rubber communication on atmospheric resistance the conical windlass* requisite strength of steam boilers bagley's gold pens the humming bird (illustrated articles are marked with an asterisk.) * * * * * [illustration: poetry] nature's image of washington. by marshall s. pike, of the harmoneons descriptive: opposite harper's ferry,--which is situated on a pleasant elevation at the junction of the potomac and shenandoah rivers--a few rods north of "pinnacle bluff," a flighty eminence on the blue ridge mountains, stands a most singular formation of rock, known as 'washington's face'; and which, to a casualist void of imaginative powers, is easily recognized if pointed out by a guide; but to a close observer, however, with common discernable perception, it presents _at first sight_ a most striking and correct resemblance of _the great original_. from midway the bridge which crosses the potomac, the countenance and contour of the face _to me_, appeared discriminatingly perfect, and constrained me to look upon it as _one_ of the most wonderful, and the noblest work of revealed nature. in the high barren cliffs of the blue mountain ridge, that frightfully hang o'er the trestle-built bridge, juts out into space a huge rocky bluff, which the elements rudely left broken and rough. near this, stands a bust so exquisitely fair, that the chisel of art would be uselessness there! for nature wrought well till the model was done-- an impress on stone of our great washington. the earth born from chaos at some mighty shock, left the image to rest on the high mountain rock, on a turret-like peak, in the heavens above, _as a sentinel over the country we love:_ where the sunbeam could linger till daylight had fled, where the bright stars of night, form a crown o'er its head; and where, through the greenwood, the faintest breeze creeps, to sigh for the hero, who deathlessly sleeps. there it stands like a giant in storm and in calm, like the hero in battle, no foeman could harm! and commandingly looks with a patriot's pride, on the wild mountain stream of potomac's fast tide, whose waters swell on in the valley between, through the vast hilly regions and forests of green; o'er a rock-bottomed track, to the blue-bosomed sea, from its struggles to rest, like our sire of the free. stand up there in might, till the bright sun shall die, till the stars glimmer out their light in the sky, and the moon shall no longer lend beauty or light, but _all_ shall again be dark chaos and night,-- till then, let its base be the tall craggy steep, where rocks are o'er moss-grown, and ivy-vines creep; with the heaven's wide canopy over its head, _an immortal image of greatness that's dead._ * * * * * [illustration: the viol seraphine] introduction.--the clear tones of a viol or bass viol are generally admitted to be more melodious than those produced by other kinds of instruments, and many have expressed a desire to see an instrument so constructed as to be played with keys, like the organ or piano forte, and give the tones of the violin. this is the character of the instrument here introduced. it is elegant in appearance; occupies less than half the space of a piano forte, and is so light and portable that a lady-performer may readily place it before her, and thus avoid the necessity,--unpleasant to all parties,--of turning her back on the company. we do not say that an instrument of this kind has been as yet constructed complete: but the principle has been proved, and it may, and probably will be soon, offered to the public, at a cost not exceeding sixty dollars. explanation.--in the engraving, a side view elevation only is represented, showing only one string and one key of a series of twenty or more of each. the body of the machine a b, is a light hollow chest about three feet square and six inches deep, supported by four posts or legs with castors. two bridges, c and d, extend across the breadth of the chest. the bridge d is supported by a cleat, e, in which is inserted the pin f, to which is attached one end of the string c d f. the other end of the string is simply attached to the bridge c. a key-lever, g h, passes through the bridge, and is mounted on a pivot therein. the front end of the key (g) is held in its ordinary position by a small spring thereunder, and may be easily depressed by the finger of the performer: the other end of the key serves as the bearing of the pivot of a delicate arbor, the opposite pivot of which has its bearing in the bridge d. on the front end of this arbor is a wheel three-fourths of an inch in diameter, with its periphery smooth, and polished with rosin, or rosin varnish; and so adjusted, that by the depression of the key, this wheel is brought up in contact with the string, whereby, if in motion rotarily, a full sound is produced, as if a violin bow was drawn across the string. on the other end of the arbor is a grooved pulley, over which passes a silken cord, which also passes round a delicate band-wheel, i, below, and by which, motion is communicated to the arbor and sounding wheel. the band-wheel is mounted on a shaft, i j, which has its bearings in two small head blocks which project from two crossbars: and from the block j is suspended a vertical rod, to the bottom of which is attached a treadle, k l, and from which a curved ratch, l m, extends upward and takes to a small ratchet on the shaft i j; so that, by the horizontal motion of the treadle, the motion is communicated to the wheel, &c. the teeth of the ratch and ratchet have so gentle an inclination on one side of each, that although the ratch applies force to the ratchet in the upward direction, they slide freely over in their return. it may be understood that the machine is to have two treadles and two ratches, which move forward alternately: and that twenty or more arbors, pulleys, strings and keys are arranged in series, although only one of each is represented in the engraving. the cord applies to each pulley in the series, by passing over the first, under the second, and over the third, and so on, descending from the last of the series to the band-wheel. each arbor is placed directly under its respective string, and it is also proposed to place moveable stops under the strings, at equal distances from the key bridge, and to regulate the tones by adjusting the stops, without depending on the pins at the ends for that purpose. we shall employ a competent mechanic to construct one or more of these instruments as soon as convenient, and give due notice accordingly. * * * * * an eclipse in arabia. casting my eyes over the bright, full moon, i perceived that an eclipse was just coming upon it. what astronomer had calculated this eclipse for arabia? it was indeed a privilege to witness one in the bright sky that over-spread the lonely mountains of seir. soon we were seated in a circle, with our arabs round their watch-fire, enquiring of them their views of an eclipse, and explaining to them ours. they appeared to have no idea of its real cause, regarding it as a judgment from god, a sign of a bad season, and little camel feed. when we undertook to explain to them the theory of the earth being round, turning over every day, sometimes getting between the sun and moon, they seemed to look upon us as telling very strange tales. the eclipse was nearly total. i gazed upon it with interest, and then eyed the strange scene around me. the wild, lonely landscape of rock and sand--the camels kneeling round the bivouac--the wild faces of the arabs, reflecting the red light of the fire round which they were seated--their wild voices and strange guttural language, all combined to produce an effect so startling, that i felt till then i had never been thoroughly sensible of our complete separation from the civilized world. * * * * * giving credit. "one of our exchange" says one of our exchanges, "came to us this week with four of our editorials _not credited_." a frivolous complaint. not a week passes but we find in some of our exchanges from ten to twenty of our editorials; and instead of complaining, we are thankful for being thus complimented. * * * * * the bowie knife and its inventor. this instrument was devised by col. james bowie, an american, and a man of desperate valor. he considered, and apparently with justice, too, that, in close fighting, a much shorter weapon than the sword ordinarily in use, but still _heavy_ enough to give it sufficient force, and, at the same time, contrive to cut and thrust, would be far preferable, and more advantageous to the wearer. he accordingly invented the short sword, or knife, which has since gone under his name. it is made of various sizes; but the best, i may say, is about the length of a carving knife--case perfectly straight in the first instance, but greatly rounded at the end on the edge side; the upper edge at the end, for the length of about two inches, is ground into the small segment of a circle and rendered sharp; thus leaving an apparent curve of the knife, although in reality the upturned point is not higher than the line of the back. the back itself gradually increases in weight of metal as it approaches the hilt, on which a small guard is placed. the bowie knife, therefore, has a curved, keen point; is double edged for the space of about a couple of inches of its length; and when in use, falls with the weight of a bill hook.--bowie went to texas during the troubles which preceded the independence of that country,--and was lying sick in bed at the fortress of the alamo, when, on the th of march, , it was stormed by santa anna and taken. bowie was murdered there upon his pillow. the hand that formed the dreadful knife could no longer wield it. * * * * * forests and streams. that remarkable man, humbolt, has reduced it almost to a demonstration, that the streams of our country, fail in proportion to the destruction of its timber. and of course, if the streams fail, our seasons will be worse; it must get drier and drier in proportion. humbolt, speaking of the valley of araguay in venezuela, says that the lake receded as agriculture advanced, until the beautiful plantations of sugar-cane, banana and cotton-trees, were established on its banks, which (banks) year after year were farther from them. after the separation of that province from spain, and the decline of agriculture amid the desolating wars which swept over this beautiful region, the process of clearing was arrested, and old lands grew up in trees with that rapidity common to the tropics, and in a few years the inhabitants were alarmed by a rise of the waters, and an inundation of their choice plantations. * * * * * prussian music. the boston brigade band has been presented with a copy of the collection of the celebrated martial music of the prussian army. prussia has long been famous for the excellence of its military bands, and the music which they have produced is of the highest order. we hope this attempt to introduce it into our city will improve the style of martial music here. * * * * * philosophy. "uncle jo," said an observing little boy, "our folks always put up the window when the room is filled with smoke, and the wind always blows in so as to prevent the smoke from going out that way: now where does the smoke go?" "it goes into the people's eyes," was uncle jo's philosophic answer. * * * * * polite preaching. a certain preacher, when treating on the subject of repentance, said, "my dear hearers, you must repent; if you do not, you will go to a place which it would be improper to mention in this polite assembly." * * * * * mr. h. longfellow of cincinnati, has about one hundred acres under culture of grapes, strawberries, peaches and raspberries. [illustration: variety.] pure air. throw open the window and fasten it there! fling the curtain aside and the blind, and give a free entrance to heaven's pure air, 'tis the life and health of mankind. behold that dull concourse in yonder closed space, with visages sluggish and red; how calmly they sit, each one in his place, while their lungs with poison are fed. what makes the grave deacon so drowsy at church? the scholar so dull in his class? dry sermons!--dry studies!--the brain's in the lurch, for want of pure oxygen gas. come, 'rouse, from your stupor, before it's too late, and do not yourself so abuse-- to sit all day with your feet on the grate; no wonder you're getting the "blues!" are you fond of coughs, colds, dyspepsia and rheums? of headaches, and fevers and chills? of bitters, hot-drops, and medicine fumes, and bleeding, and blisters and pills? then shut yourself up like a monk in his cave, till nature grows weary and sad, and imagine yourself on the brink of the grave. where nothing is cheerful and glad. be sure when you sleep, that all is shut out: place, too, a warm brick to your feet-- wrap a bandage of flannel your neck quite about and cover your head with the sheet. but would you avoid the dark gloom of disease? then haste to the fresh open air, where your cheek may kindly be tanned by its breeze; 'twill make you well, happy and fair. o, prize not this lightly, so precious a thing; 'tis laden with gladness and wealth-- the richest of blessings that heaven can bring, the bright panacea of health. then open the window, and fasten it there! fling the curtain aside and the blind. and give a free entrance to heaven's pure air, 'tis light, life, and joy to mankind. * * * * * the deerfield (n. h.) phenomena. we have frequently heard of singular and unaccountable reports, as of explosion, in deerfield, but nothing so definite as the following statement by a correspondent of the portsmouth journal. "mr editor,--during the last twelve years, certain curious, not to say alarming phenomena in the town of deerfield, n. h., have excited the fears of the inhabitants, and we think should, ere this, have attracted the attention of the scientific. these are reports of explosions in the ground, apparently of a volcanic or gaseous nature. when first heard they were attributed to the blasting of rocks in manchester, a new town some ten miles distant; but from the frequency of the reports at all hours in the night as well as the day, from the consideration that they were so loud, and were heard in all seasons, winter as well as summer, it was soon concluded that they had some other origin. the explosions, if they may be so called, commenced on a ridge of land running s. e. and n, w, some five miles in length, and principally on that portion called the south road. they have, however, extended, and arc now heard in a northerly direction. the sounds have become louder, and during the last fall and the present spring or summer, as many as twenty have been heard in one night. many of them jar the houses and ground perceptibly, so much so, that a child whose balance is not steady, will roll from one side to the other. they are as loud as a heavy cannon fired near the house, with no reverberation, and little roll. last fall some of the inhabitants were riding in a wagon when an explosion was heard, and they saw the stone wall, which was apparently quite compact, fall over on one side of the way, and a second after upon the other. the stone wall of an unfinished cellar also fell in. this can be attested by many witnesses. there is no regularity in these reports, as they are heard at intervals of a day, a week, and sometimes of months: but for the last year they have become very common, and are heard almost every week more or less." * * * * * extraordinary instance of gambling. it is well known upon the western waters, that the firemen and other hands employed upon the boats spend much of their idle time in playing cards. of the passion for gaming, thus excited, an instance has been narrated to us upon the most credible authority, which surpasses the highest wrought fictions of the gambler's fate. a colored fireman, on board a steamboat running between saint louis and new-orleans, had lost all his money at poker with his companions. he then staked his clothing, and being still unfortunate, pledged his own freedom for a small amount. losing this, the bets were doubled, and he finally at one desperate hazard, ventured his full value as a slave, and laid down his free papers to represent the stake. he lost, suffered his certificates to be destroyed, and was actually sold by the winner to a slave dealer, who hesitated not to take him at a small discount upon his assessed value. when last heard of by one who knows him, and informed us of the fact, he was still paying in servitude the penalty of his criminal folly. * * * * * gen. taylor's patriotism. in answer to the complimentary resolutions passed at a meeting in this city some weeks since, gen. taylor says, "it is a source of gratulation to me that the meeting refrained from the meditated nomination for the presidency. for the high office in question i have no aspirations. the government has assigned to me an arduous and responsible duty in the prosecution of the existing war: in conducting it with honor to the country lie all my real aspirations." * * * * * the columbian magazine. the october number of this splendid work will be found to be equal, if not superior, to anything and everything of the kind in the literary region. it presents three superb embellishments--"a cure for love," mezzotint, by sadd; "view on the st. lawrence," fine steel engraving, by c. f, giles, and a plate of fashions; in a new style, besides a piece of first rate music. this work is published monthly by isreal post, nassau st. terms, only $ per annum. * * * * * a mountain in labor. the workmen, says a paris paper, are still busily engaged in excavating montmartre in quest of holy vases and other riches said to have been deposited there in early days of the french revolution by the orders of lady superior of the abbey of montmartre. two workmen, who were at the time charged with transporting the wealth to the place designated were never seen, and it is supposed that they were sacrificed to the necessity of the secret. the superior, at her death, bequeathed the secret to a lady friend, who in turn, on her death bed, divulged it to her daughter, then years of age. the child, now a sexagenary, disclosed it to the municipiality. her statements have thus far been found scrupulously correct. the _cesarian_ operation is actively going on, an excavation of fifty feet having been made, and the mountain's speedy deliverance of a mine of wealth is anticipated. may it not prove a mouse! * * * * * the pope's will. the late pope has left a fortune of eleven millions of francs, which, after some religious bequests; is to be divided among his relations! upon the singular condition that they never contest the will, and that they never take up their residence in rome. * * * * * improved railroad. the harlem railroad company have laid down a section of their road with cast iron rails of a new construction, invented by mr. imley. these rails are highly approved, and are expected to supersede the common wrought rails to a considerable extent. * * * * * it is reported that mr. isaac fisk of massachusetts, spells his name "eyzurk physque." well, what if he does? * * * * * sageisms. he who is passionate and hasty is generally honest. it's your cool, dissembling, smiling hypocrite, of whom you should beware. there is no deceit about a bull dog. it's only the cur that sneaks up and bites you when your back's turned. again, we say, beware of a man who has psalmody in his looks. if a person is bent on quarrelling with you, leave the whole of it to himself, and he will soon become weary of his unencouraged occupation. even the most malicious ram will soon cease to butt against a disregarding object, and will usually find his own head more injured than the object of his blind animosity. so let them kick. an easy flow of words is no sign of an abundance of ideas. swift made a wise comparison when he likened a well stored mind to a crowded church, where the people elbow each other, and cannot get out. "if a civil word or two will render a man happy," said a french king, "he must be a wretch indeed who will not give them to him. such a disposition is like lighting another man's candle by one's own, which loses none of its brilliancy by what the other gains." * * * * * in preparation. we have in course of preparation for future numbers, some large and elegant engravings, illustrative of some of the most interest and deeply scientific _new inventions_, together with illustrations of architecture, geometry and magnetism. also a variety of intelligence in _arts and trades_. * * * * * a strong position. "gentlemen of the jury," said an eminent lawyer, "there are four points in this case. in the first place, we contend that we never had the plaintiff's horse; second, that we paid him for the use of the horse; third, he agreed to let us use the horse for his keeping, without any charge; and fourth, that his horse is a jackass." * * * * * as good as cash. an editor out west having asked the consent of a father to his daughter's hand in marriage, the provident old gentleman inquired how much money he could bring the bride. the editor said he hadn't got any money, but he would give her a puff in his paper. the father was satisfied. * * * * * how very hot it is. the following lines would have been inserted earlier, but the weather was so hot we could not attend to it. did you ever know such weather? seven bright burning days together! swelt'ring nights and broiling days, sultry moonbeams, sun's hot rays: no one knows which way to turn him, all things either melt or burn him; half the weight of all the nation, is flying off in perspiration, and every man, and woman too, as languidly they look at you, exclaims, with moist and mournful phiz, "dear me! how very hot it is!" ladies all languid in muslin array, loll upon couches the live long day, looking more lovely than we can say-- though, alas! they are rapidly melting away "bring me _an ice!_" they languidly cry, but alas and alack! it is "all in my eye"-- for before it reaches the top of the stairs, it's turned into water quite "unawares," while john with his salver, looks red and stares, and the moist confectioner inwardly swears, as he wipes with his apron his long, pale phiz, "oh--pooh! how infernally hot it is!" oh, what a treat 'twould be to wade chin deep in fresh ice and lemonade! or to sit a deep marble bowl within, and camphor gurgling around your chin-- hissing and sparkling round your nose, till you open your mouth and down it goes, gulp by gulp, and sup by sup, as you "catawumpishly chew it up." refreshing your heart and cooling your faces-- burnt down as they've been with all sorts of sauces oh, the fellow who thus could lave his phiz needn't care how hot the weather is! * * * * * a son of the emperor nicholas, of russia, is now travelling in the united states. he is said to be an intelligent looking man. * * * * * california farming. a gentleman, writing from california to the editors of the saint louis reveille, says his stock consists of about four thousand head of oxen, one thousand seven hundred horses and mules, three thousand sheep, and as many hogs. they all pasture! themselves without difficulty in the rich prairies and bottoms of the sacremento, and only require to be attended. this is dune by the indians, of whom he employs four hundred. his annual crop of wheat is about twelve thousand bushels, with barley, peas, beans, etc, in proportion. * * * * * diversification of language. _a poetic line from gray admits of the following twenty-eight variations without changing the accent:_ the weary ploughman plods his homeward way, the ploughman, weary, plods his homeward way, his homeward way the weary ploughman plods, his homeward way the ploughman weary plods, the weary ploughman homeward plods his way, the ploughman, weary, homeward plods his way, his way, the weary ploughman homeward plods, his way, the ploughman, weary, homeward plods, the ploughman, homeward, plods his weary way, his way the ploughman, homeward, weary plods, his homeward weary way the ploughman plods, weary, the ploughman homeward plods his way, weary, the ploughman plods his homeward way, homeward, his way the weary ploughman plods, homeward, his way the ploughman, weary, plods, homeward, his weary way, the ploughman plods, the ploughman, homeward, weary plods his way, the ploughman, weary, homeward plods his way, his weary way, the ploughman homeward plods, his weary way, the homeward ploughman plods, homeward the plowman plods his weary way, homeward the weary ploughman plods his way, the weary ploughman, his way, homeward plods, the ploughman, weary, his way homeward plods, the ploughman plods his weary, homeward way, weary, the ploughman, his way homeward plods, weary, his homeward way the ploughman plods. from the gem of the prairie. * * * * * "keep that testament in your vest pocket, over your heart." we have been forcibly reminded of an interesting anecdote of the revolution, while witnessing so many young men in the ranks of the volunteer companies, in connection with the highly praiseworthy resolution of the nashville young men's bible society, to present a copy of the new testament to each officer and private constituting the regiment quartered here. the fond-hearted mother had assisted in adjusting upon her son the "tow frock and trowsers," had tightly secured the knapsack, canteen and cartridge box in the strings twisted with her own fingers from the same material as his clothes; as he turned, on opening the door, to speak the "manly good-bye," she suppressed the parting tear, lest it might damp the flame of freedom which fired his noble soul, and echoed the "good-bye" with a forced smile. as she went to the window to take another look, she discovered the testament had been forgotten; she caught it in her hand, ran to the door--called him loudly, holding the book in her uplifted hand, in order to show him why she stopped, and soon stood by his side. without uttering a word she put the book in its place, grasped his hand, looked him full in the face, and with quivering lips, heart big with emotion, checks bedewed with tears of maternal affection, she spoke: "my son, i would not have you stay; your country has the first claim upon you; be true to that as you have been dutiful to me, and heaven will protect you--keep that testament in your vest pocket, over your heart!" after faithfully serving the term of his enlistment, he returned to his home. before he uttered a word, he took from his "vest pocket" the old testament, and there lay british bullet, snugly imbedded where the force of the powder had driven it, and this was the only shot he had received while fighting for his country.--_nashville union_. * * * * * temperance in the army. we are gratified to learn that gen. taylor has totally prohibited the traffic in intoxicating liquors in the vicinity of the army. one fellow, persisting in the trade, was put in the guard house by capt. miles: and when liberated, on going to gen. taylor's tent with a complaint, was kicked out. he finally took marching orders _t'other way_. * * * * * modes of raising ponderous articles. a wedge is considered to be the most simple of "mechanical powers," and is often used in cases where no other apparatus can be made to apply; as in splitting logs and other adhesive articles. if a massive rock is to be elevated from the ground, a wedge must first be driven between that and its foundation, preparatory to the application of levers. yet the wedge is in most cases objectionable on account of the friction with which its use is attended. the next, and most common power applied for elevating buildings on large rocks, is the simple lever, commonly called a pry. this usually consists of a long straight beam or pole, one end of which is placed under the object to be raised, while a fulcrum consisting of a stone or block of wood, is placed under the lever, at a short distance from the object to be raised. the opposite extremity then being forced down by the weight of one or more of the workmen, a force is applied to the object to be raised, bearing the same proportion to that applied to the lever, that the distance between the fulcrum and the extreme end of the lever does to that between the fulcrum and the object. levers made of iron, and simply denominated "iron bars," are commonly used in raising and removing rocks. a machine called a "bed-screw" is frequently used for elevating buildings. it originally consisted principally of a large vertical screw, which was placed on a foundation called the "bed," and was turned by levers; but many improvements and variations have been added, till, in some instances, the screw has been dispensed with, and a rack and pinion have been substituted. some of the best in use consist of a vertical iron rack, which is occasionally forced upward by the teeth of a pinion: a geer wheel on the same axle with the pinion being driven by the thread of a horizontal screw, to the head of which is attached a crank. by a machine of this construction, properly proportioned, one man may raise about twenty tons weight. vertical screws, turned by levers, have been frequently used for the purpose of raising vessels to repair. but in these cases a large portion of the power applied is lost in the friction of the screw, and the process is laborious and tedious. this is probably the most awkward and injudicious method that has been applied to that purpose. another method which has been applied to the purpose of elevating vessels, is decidedly ridiculous, although less laborious than the former. it is called the "hydraulic power," and consists in forcing water into large cylinders, by forcing pumps which are operated by steam power; while the water thus forced into the cylinder moves a piston and piston-rod, to which is connected several stout chains, which passing over corresponding pulleys, descend to a platform, on which rests the vessel to be raised. an expensive apparatus, called the "marine railway," constructed on the principle of the _inclined plane_, with a huge and complicated carriage to travel thereon, has been extensively used for taking vessels out of the water to repair. this plan is objectionable, however, on several accounts. it requires the application of a great quantity of power to overcome the friction of its many axles and machinery, in addition to what is requisite to overcome the gravity of the vessel. it is, moreover, injurious to the vessels which are taken up thereby, on account of its elevating the forward part, before the centre and stern become seated on the carriage. the most judicious mode in present use, for raising vessels to repair, and which must be preferred to all others, where there is a supply of water from an elevated reservoir, is on the principle of locks; the vessel being floated into one apartment, is elevated by the induction of water from above, till it can be floated over an elevated platform, where it is left at rest, while the water is allowed to pass off below. the sides of this upper box or apartment, are moveable, being attached to the bottom or platform by hinge joints, so that they may be let down to a horizontal position, thus giving the workmen the advantage of light and convenience. the "dry dock" in the navy yard at charlestown, mass., is constructed awkwardly enough; but as the vessels at that place are not _raised_, it does not come under this head. the massive stones which were used in the construction of some of the ancient edifices, were evidently raised by inclined planes. a huge mound of earth was built up round the building, completely enclosing it; and the elevation of the mound kept pace with that of the edifice: thus giving the laborers a chance to roll up the stones to their places. they used no other mechanical power than the simple windlass and lever; and no other carriage than a drag, under which was placed rollers. when the building was completed, the earth was taken away, and levelled about the vicinity. the modern method of raising stones for building, and which is now used in the building of heavy stone edifices, is by the use of a set of stout tackle blocks, the _fall rope_ of which is taken up by a geered windlass, operated by a steam engine; the upper block being of course attached to an elevated _shears_ or derick. vessels, and other bodies, which have been sunk in the ocean, have been sometimes raised by means of airtight sacks, attached to different parts of the object by means of diving bells, been inflated with air, forced down through hollow tubes by pumps, till they thus acquired a buoyancy sufficient for the purpose. the power of buoyancy has also been applied for elevating vessels above water, by placing hollow trunks, filled with water, under the keel of the vessel, and then pumping them out. one of the best methods that has ever yet been proposed for raising vessels to repair, is to place under the keel a horizontal platform, to which is attached four large hollow trunks under its four corners: the trunks to be filled with water, and to have open apertures in the bottom of each. then by allowing a stream of atmospheric air, to rush by its own expansive force from the reservoirs in which it had been previously compressed, through suitable pipes or hose, into each trunk, the water is expelled through the apertures in the bottom, and the vessel is elevated immediately, and without loss of time. in this case, the reservoirs (iron cylinders) of compressed air, may be recharged by steam or other power, during the process of repairing one vessel, and be thus in readiness for another. a patent has been granted for this invention, but it has not yet been put in operation on a scale of practical use, though the patentee would willingly give the right of the patent to any person or company who should be disposed to construct the apparatus on a large scale. we have recently given a description of mr. spencer's plan for elevating vessels, and some other modes have been recently projected, which we may describe in a future number. * * * * * information to persons having business to transact at the patent office. sec. . the existing laws relating to patents are those approved july , , march , , and march , ; all former acts having been repealed by the act of . sec. . "patents are granted for any new and useful art, machine, manufacture, or composition of matter, or any new and useful improvement on any art, machine, manufacture, or composition of matter, not known or used by others before his or their discovery or invention thereof, and not, at the time of his application for a patent, in public use, or on sale, with his or their consent, or allowance, as the inventor or discoverer." act of , section . "no patent shall be held to be invalid by reason of the purchase, sale, or use [of the invention,] prior to the application for a patent as aforesaid, except on proof of abandonment of such invention to the public, or that such purchase, sale or public use, has been for more than two years prior to such application for a patent."--act of march , . sec. . the term for which a patent is granted, is fourteen years; but it may, under certain circumstances, be renewed for seven years, as hereinafter mentioned. sec. . patents are granted to citizens of the united states, to aliens who shall have been resident in the united states one year preceding, and shall have made oath of their intention to become citizens thereof, and also to foreigners who are inventors or discoverers. sec. . a patent may be taken out by the inventor in a foreign country, without affecting his right to a patent in the united states, provided the invention has not been introduced into public and common use in the united states prior to the application for such patent. in every such case the patent is limited to fourteen years from the date of the foreign letter patent. a patent is not granted upon introduction of a new invention from a foreign country, unless the person who introduced it be the inventor or discoverer. if an alien neglects to put and continue on sale the invention in the united states, to the public, on reasonable terms, for eighteen months, the patentee uses all benefit of the patent. sec. . joint inventors are entitled to a joint patent, but neither can claim one separately. sec. . an invention can assign his right before a patent is obtained, so as to enable the assignee to take out a patent in his own name; but the assignment must be first entered on record; and the application therefor must be duly made, and the specification signed, and sworn to by the inventor. and in the case of an assignment by a foreigner, the same fee will be required as if the patent issued to the inventor. sec. . the assignment of a patent may be to the whole or to an undivided part, "by any instrument in writing." all assignments, and also the grant or conveyance of the use of the patent in any town, comity, state, or specified district, must be recorded in the patent office, within three months from date of the same.--but assignments, if recorded after three months have expired, will be on record as notice to protect against subsequent purchases. no fee is now charged for recording assignments. patents, grants, and assignments, recorded prior to the th of december, , must be recorded anew before they can be valid as evidence of any title. this is also free of expense. sec. . in case of the decease of an inventor, before he had obtained a patent for his invention, "the right of applying for and obtaining such patent shall devolve on the administrator or executor of such person, in trust for the heirs of law of the deceased, if he shall have died intestate; but if otherwise, then in trust for his devisees, in as full and ample manner, and under the same conditions, limitations, and restrictions, as the same was held, or might have been claimed or enjoyed, by such person in his or her lifetime; and when application for a patent shall be made by such legal representatives, the oath or affirmation shall be so varied as to be applicable to them."--act of , sec. . sec. , the patent office will be open for examination during office hours, and applicants can personally, or by attorney, satisfy themselves on inspection of models and specifications, of the expediency of filing an application for a patent. sec. . all fees received are paid into the treasury, and the law has required the payment of the patent fee before the application is considered; two-thirds of which fee is refunded on withdrawing the application. but no money is refunded on the withdrawal of an application, after an appeal has been taken from the decision of the commissioner of patents. and no part of the fee paid for caveats, and on applications for the addition of improvements re-issues, and appeals, can be withdrawn. sec. . it is a frequent practice for inventors to send a description of their inventions to the office, and inquire whether there exists any thing like it, and whether a patent can be had therefor. _as the law does not provide for the examination of descriptions of new inventions, except upon application for a patent, no answer can be given to such inquiries_. * * * * * a sentimental writer says it is astonishing how much light a man may radiate upon the world around him, especially when the body he admires is beside him. * * * * * among the persons who recently laid in the boston jail over sunday, and were fined monday morning for intemperance or rowdyism, were a member of the bar and a clergy man. * * * * * said a bishop to a rough wagoner, "you seem better fed than taught." "of course," replied the fellow, "for we _feed_ ourselves, but for teaching we depend on _you._" * * * * * [illustration: the reg(ulator?)] the use of a pair of conical drums in reversed position, and connected by a band, as shown in the cut, has been known for several years to a few, but yet are not extensively known, and but a few of them have been seen in operation in this country. it will be seen that if the band be removed laterally, either to the right or left, the relative motion of drums will be materially varied. these drums being arranged to constitute a connection of motion between the driving power and driven machine, may be made to render the motion of the latter either regular or irregular at the option of the operator. if the band connecting the drums, is governed by a shifting lever connected with a _governor_, it may be so adjusted as to keep the motion of the machine regular, although the driving power should be irregular in its motion, as is the case with a wind-wheel. but if the operator is engaged, requires a move rapid motion at one time than at another, he can accommodate himself by shifting the position of the cone-band, to the right or left, as occasion may require. this is very convenient for turners, whose business requires at some times a rapid speed of the mandrill, and at other times a slow or gentle motion. these drums, as represented, must be swelled in the centre, that the band may be kept uniformly straight. * * * * * a remarkable mineral spring. it may not perhaps be generally known even to our own citizens that there is in the town of riga, n.y., one mile east of churchville, on the farm of linus pierson, a mineral spring, the gases from which are sufficiently combustible to burn as clear and brightly as a lamp, at all times of the day and night, and which is never exhausted. the spring is located near the bathing-house on the farm, and a tube has been constructed, leading from the spring to the rooms, by means of which the house is made sufficiently light without the use of lamps. some time ago the state geological surveyors paid this spring a visit, and analyzed the gas, which was found to be composed of sulphurated and carbonated hydrogen. the water is strongly impregnated with iron. * * * * * cool forethought. one of the most admirable instances of prudential forethought we have ever heard of, occurred in boston a few days since. three irishmen were engaged in taking down a wall in mount vernon street. the wall fell upon and buried them. a lady from the opposite side of the street rushed out, and calling to those who were rescuing the poor fellows, said, "bring them in here. bring them in here. i have been expecting this all day." the men were carried into her house, and, true enough, she had "every thing ready," bandages, lint, laudanum, and all. if this be not an instance of _cool forethought_, we know not what is. * * * * * it may be so. it is stated in a cincinnati paper, that the body of a drowned child has been discovered by means of a loaf of bread in which was deposited a quantity of quicksilver. the loaf was sent afloat in the canal, and after floating some distance, remained stationary, and beneath the spot thus indicated, the child was found. that mercury may have a natural attraction towards a human body, is possible; but the use of the loaf of bread in combination, indicate a superstitious faith rather than real science. * * * * * several rich lead mines have recently been discovered on the mississippi river, a few miles above bellevue. the unusual low state of the river lead to the discovery. * * * * * new inventions. howe's sewing machine. we have heretofore noticed the extraordinary invention by mr. elias howe, jr., of cambridge, mass.--a machine that sews beautiful and strong seams in cloth as rapid as nine tailors. we are not yet prepared to furnish a full description of this machine, but the following claims, in the words of the patentee, may give some idea of the various parts in combination. this machine was patented september th. "i claim the lifting of the thread that passes through the needle eye by the lifting rod, for the purpose of forming a loop of loose thread that is to be subsequently drawn in by the passage of the shuttle; said lifting rod being furnished with a lifting pin, and governed in its motions by the guide pieces and other devices. "i claim the holding of the thread that is given out by the shuttle, so as to prevent its unwinding from the shuttle bobbin, after the shuttle has passed through the loop, said thread being held by means of the lever, or clipping piece. "i claim the manner of arranging and combining the small lever, with the sliding box in combination with the spring piece, for the purpose of tightening the stitch as the needle is retracted. "i claim the holding of the cloth to be sewn, by the use of a baster plate, furnished with points for that purpose, and with holes enabling it to operate as a rack, thereby carrying the cloth forward, and dispensing altogether with the necessity of basting the parts together." * * * * * steering apparatus. mr. r. c. holmes, says the united states gazette, has invented a new application of the tiller rope to the wheel for steering vessels, and has prepared a model of the whole application, tiller-frame, wheel, and rope, so that the properties of the invention can be easily discovered. the advantages are that there is no slack made; and, consequently, there is no chafing, and a single hand at the wheel will do the ordinary work of two men. * * * * * electro-magnetic boat. it is stated in some of our exchanges, that dr. page, of washington, has perfected a boat to be propelled by the electro-magnetic power. we know of no man better qualified to produce and introduce successfully such an invention, and we feel assured that whatever enterprise dr. page undertakes in that line, will be very apt to go ahead. we hope soon to obtain further intelligence on the subject. * * * * * it is reported that the british government has granted $ , per annum to the royal company of atlantic steamers, for the establishment of a post route to the pacific, across the isthmus of panama. * * * * * improvement in boats. there is a model of a steamboat to be seen on the chesapeake, invented and constructed by cyrus williams, esq., which is exciting considerable interest among steamboat men. it is in the usual form of a boat, but more flat-bottomed, and much longer in proportion to its width, than the boats now in use, giving it a greater surface to the water, and of course a lighter draught. the improvement is in applying the bridge principle of bearers in supporting length of boats. it looks perfectly feasible. mr. williams thinks it will be a great saving of expense, as it takes much less timber, and all of it can be sawed in a mill, being straight stuff. he offers to build a boat on this model, furnishing one third of the stock, and if it does not make miles to the hour, he will forfeit his share. * * * * * casting iron cannon by a galvanic process. a hoaxical looking article, under the above caption, is going the rounds, and represents that successful experiments on this subject have been recently made at berlin. as no description or illustration of the process or principle is given, we leave the subject for those who are ever ready to swallow whatever appears in a newspaper, without regard to probability. * * * * * new shingle machine. among the patents particularly noticed in the commissioner's report, is one for a shingle machine, which cuts the shingles in a peculiar form. the shingles cut by this machine does not taper from one extremity to the other, but the taper is confined to about half the length of it at one end, the faces of the remaining half being parallel to each other. this shape of the shingle avoids the bending which is incidental to those of the ordinary form, when nailed upon the roof--an object well worthy of attainment. * * * * * improvement in blacksmiths forges. this invention was entered at the patent office on the th instant, by james k. hobbs. the improvement consists in the placing of grate-bars at the bottom of the fire chamber, below which is an open air chamber into which the cinders and ashes fall through the grate, instead of accumulating and clogging the fire chamber. the cinders may be drawn out of the air chamber by an opening at the side of the forge. the blast is admitted above the grate, and the mouth of the air chamber being ordinarily closed, the blast is not affected by the grate. we think it must prove a useful invention. * * * * * improved fire engine. this improvement consists in part, in the arrangement of two sets of levers and hand poles on each side, in such a manner that "when force is applied to the hand-poles of the outside levers, in a reverse direction to that which is applied to the hand poles of the inside levers, both powers will agree in forcing the pistons of the pumps in one and the same direction, while the reverse motion of the levers will prevent the engine from rocking". entered at the patent office, on the th instant, by barton & button. * * * * * a simple cheese-press. [illustration] an ingenious mechanic, not long since, hearing some persons conversing on the ordinary cost of cheese-presses, which is generally from three to six dollars, boldly averred that he could build a cheese-press in one hour, which would answer a good purpose as such, and which might be afforded for fifty cents. being bantered on the subject, he went to work, and by means of a good lathe and boring machine, he actually produced his cheese-press within the hour; though not very smoothly finished. we give a sketch of it at the head of this article,--too plain to require explanation. subsequently, several others were made on the same plan. * * * * * cast iron roofing. a specimen of cast-iron plates for roofing of buildings, says the philadelphia ledger, has been exhibited at the exchange, in philadelphia, by the inventor and patentee, mr. wm. beach. the plates are about a foot square, and are made to fit one into another so as to render the roof perfectly water-tight, with the application of white lead to the joints. in every respect this material for roofing is preferable to any other description now in use. as to its durability, there can be no doubt that it would remain perfectly whole for ages, if covered occasionally with a coat of paint, and even without that preservative, rust would not affect it materially for a period of fifty years at least. as compared with copper, the cost would be nearly one half, as it is expected the iron can be furnished at cents per square foot, while copper would at the most moderate estimate cost cents. as regards the weight of an iron roof, which at first sight would appear an objection, it is far less than one formed of slate, and does not much exceed one of copper. the iron plates weigh three and a half pounds per square foot. a slate roof would cost about eight cents per square foot, but for durability, and the ease with which it can be put on and made water tight, the iron roofing would appear to be far preferable. the plates exhibited were cast at troy, new york, and are of the very best quality. the patent for the eastern states is now owned by mr. hiram hemmistone, of troy, in which neighborhood the adaptation of such a durable material for roofing is rapidly attracting public attention there. starbuck's machine shop and foundry at troy has been covered on this plan, and it has also been adopted for the roofing of an arsenal at west point. * * * * * the new and wonderful pavement. we presented in a late number, a brief extract from an article on this subject from the "eureka," and should have thought no more of it, had we not observed the following notice editorial in the n, y. farmer and mechanic. we copy the article entire, that our readers may judge for themselves whether the style and statements savor most of reality or humbug. "new pavements.--a new system of making streets has been made known to us;--but as it will be the subject of patents, here and in europe, we can only give some of its most prominent features. a material or composition, of a very cheap character, has been invented, as hard, strong and compact as flint. it is formed into any desirable shape in the course of manufacture. from this, streets of any grade may be formed, and in such a way as to entirely secure a permanent and level surface to its proper arch; it can be taken up in five minutes, so as to get at the water pipes, and on being replaced will, from necessity, resume its first position. in durability, it will last ten times as long as granite, and twenty times as long as the common paving, without liability to require repair. it is so laid that frost and storms cannot affect it. but we shall have occasion to refer to it again".--persons wishing information may inquire of kingsley & pirsson, no. wall street. * * * * * to render shingles durable. one of our exchanges mentions an experiment which was made twenty-seven years ago, of dipping shingles into hot linseed oil prior to nailing them on the roof: and although they have not been painted, they are said to continue perfectly sound as when first put on. they were of the common pine, and as much exposed as roofs in general. this instance may be sufficient to establish the fact that shingles thus prepared, will last longer without painting than they could possibly be preserved by painting in the usual way. as a security against fire, however, we should recommend that they be first dipped in a hot solution of common salt; and afterward, when dry, be dipped in the hot oil. the expense will be trifling, and there can be no doubt of their durability, and there will be no danger of their taking fire from sparks or cinders. * * * * * best plan of a barn. perhaps no building on the farm in the northern states is of more importance than the barn. those who have had the charge of cattle during our long winters, can at once see that much time and hard labor could be saved by a judicious arrangement of stalls, and bay or bay lots, granaries, &c, so that every creature could be fed by taking as few steps as possible. one very important thing to be considered, is the best mode of preserving as well as collecting manure, so that it shall retain all its valuable properties in the spring, and be easily got out. we like the plan of having a barn on the side of a hill, and so arranged that you may drive your cart load in pretty near the ridge pole, and thus pitch most of your hay down instead of up. having your stalls under the hay, you can continue to pitch the hay down, and if you have a cellar beneath, you can throw the manure down also, and thus make the attraction of gravitation perform much of the labor of transportation from the mow to the manure cart. * * * * * the westfield, mass., news-letter states that there are between and manufacturers of whips in that town, who employ not less than braiders, beside their shop hands. * * * * * robert fulton. robert fulton, a celebrated engineer, whose name is connected with steamboat navigation, was born in the town of little britain, in the state of pennsylvania, in . his genius disclosed itself at an early period. he was attracted to the shops of mechanics; and at the age of seven he painted landscapes and portraits in philadelphia. thus he was enabled in part to purchase a small farm for his widowed mother. at the age of twenty-one, he by the advice of his friends repaired to london, to place himself under guidance of mr. west, the painter, and by him was kindly received, and admitted as an inmate of his house for several years. prosecuting his business as painter, he spent two years in devonshire, where he became acquainted with the duke of bridgewater and with lord stanhope, well known for his attachment to the mechanic arts. in , he engaged in the project of improving inland navigation, and in , obtained patents for a double inclined plane, and for machines for spinning flax and making ropes. the subject of canals now chiefly occupied his attention, and at this period, in , his work on canals was published. in his profession of civil engineer he was greatly benefitted by his skill in drawing and painting. he went to paris in , and being received into the family of joel barlow, he there spent seven years, studying chemistry, physics and mathematics, and acquiring a knowledge of the french, italian, and german languages. in dec. , he made his first experiment on sub-marine explosion in the seine, but without success. his plan for a sub-marine boat was afterwards perfected.--in , while he was residing with his friend, mr. barlow, he met in paris chancellor livingston, the american minister, who explained to him the importance in america of navigating boats by steam. mr. fulton had already conceived the project as early as , as appears by his letter to lord stanhope. he now engaged anew in the affair, and at the common expense of himself and mr. livingston built a boat on the seine, in , and successfully navigated the river. the principles of the steam engine he did not invent; he claimed only the application of that machine to water wheel, for propelling vessels. in he returned to america; he and mr. livingston built, in , the first boat, the clermont, feet in length, which navigated the hudson at the rate of five miles an hour. nothing could exceed the surprise and admiration of all who witnessed the experiment. the minds of the most incredulous were, changed in a few minutes. before the boat had made the progress of a quarter of a mile, the greatest unbeliever must have been converted. the man who, while he looked on the expensive machine, thanked his stars that he had more wisdom than to waste his money on such idle schemes, changed the expression of his features as the boat moved from the wharf and gained her speed, and his complacent expression gradually softened into one of wonder. the jeers of the ignorant, who had neither sense nor feeling to suppress their contemptuous ridicule and rude jokes, were silenced for a moment by a vulgar astonishment, which deprived them of the power of utterance, till the triumph of genius extorted from the incredulous multitude which crowded the shores, shouts and acclamations of congratulation and applause. in february, , he took out his first patent. in and , he built two steam ferry boats for crossing the hudson; he contrived also a very ingenious floating dock for the reception of those boats. in , he obtained a patent for a sub-marine battery. conceiving the plan of a steam man-of-war, the government, in march , appropriated $ , for constructing it, and appointed him the engineer. in about four months, she was launched with the name of fulton the first; but before this frigate was finished, fulton had paid the debt of nature. * * * * * the population of great britain for the last ten years shows an average annual increase of , . the population of london has increased per cent. within fifteen years. * * * * * within the last years, steamboats have been built in pittsburg--besides the present year. * * * * * introduction to volume ii. with our best bow, we present ourselves before our friends and the public, in a new dress, from head to foot, and though conscious of appearing rather plain and quaker-like, we can assure our friends that in this, we conform to the newest fashion, and have no doubt of being treated civilly by as large a portion of the public, as if we had appeared with more gay feathers in our cap, with starched ruffles and gilt buttons and trimmings. in this, however, we would not be understood to boast, of any peculiar evidence of taste of our own, as we have been induced in this instance, to submit wholly to that of our tailors, who it must be conceded, understand these things much better; while we have only to regard alertness and independence of movement, with a little vivacity, and intelligence of conversation.--our general principles, and rules of self-government will continue according to our original pledge, and the policy pursued in our first volume: we shall endeavor to encourage and excite a spirit of enterprise and emulation in artists, manufactures and mechanics, while we present such instruction and useful intelligence in arts and trades, practical science and new discoveries, inventions and improvements, as will add to the facilities of enterprise, and conduce to the prosperity and independence of the working class in particular. and that we may furnish an acceptable family newspaper, we shall continue to give in a brief and condensed form, the most useful and interesting intelligence of passing events,--not omitting a small portion of serious matter, suitable for sunday reading, but avoiding the disgusting and pernicious details of crime, with which too many of our public journals abound, and which evidently produces a deleterious effect on the morals of the community. with regard to political and sectarian subjects, however, we feel much inclined to change our style of neutrality so far as to advocate all parties, sects and denominations, each in its turn, which course may be more in accordance with our own maxim of "enlightening and pleasing," than either growling policy, or the affected indifference and cold inattention which tends to produce a reciprocity of coldness, and pleases none. on the subject of policy and rules, we might say more; but having already said twice as much as we at first intended, and finding ourselves near the bottom of the scrap on which we scribble, we have only to find some suitable form of sentence wherewith to round off this subject; and for this purpose, without wishing to be suspected of any motives of interest, we would gently and respectfully suggest to our readers the propriety of advancing the intelligence, enterprise and consequent prosperity of the community, by introducing and recommending to the patronage of all, this same scientific american. * * * * * advantage of low fares. during the month of july, , when the fare between new york and boston was reduced to the "ruinous rates" of only two dollars, the receipts on the different routes were $ , ; but during the corresponding month of the present year, with the fare up to four dollars, the receipts have been only $ , : being _nine thousand two hundred and forty-five dollars_ less for a single month, than when the fares were at half-price. * * * * * avalon railroad iron. the covington manufacturing co. at their avalon works, near baltimore, are now delivering, under their contract, the iron for the baltimore and ohio railroad. this iron is made exclusively of the best quality of baltimore charcoal pig iron. the fixtures by which it is manufactured are of the most approved description, and embrace several original improvements, by means of which nearly every bar is made perfect. * * * * * the magnetic telegraph. line to burlington, vt.--a movement appears to be in progress in vermont for establishing a line of telegraphic communication from springfield or albany to burlington. much confidence is expressed by some of the vermont papers that the enterprise will be carried through. it is stated that the magnetic telegraph will extended from washington city to richmond, and completed before the middle of december next. telegraph to canada.--it affords us great satisfaction, says the montreal herald, to learn that there is a great probability of the "lightning lines"--the electric telegraph--being extended from the great cities of the united states to montreal and quebec. a gentleman is now in town, and has submitted proposals to the board of trade for making an immediate commencement with this most, important public work. this line is expected to be extended to montreal from saratoga, to which place a line is already in operation. the line between new york and buffalo having been recently completed, the following is reported to have been the first telegraphic conversation on the occasion. general chat by lightning.--at one o'clock, p. m., precisely, the telegraph line connected through the whole distance from new york to buffalo, miles. upon turning the adjusting screw of the magnet by prof. morse, all things were found right, and prof. morse sent his compliments to all the operators on the line. the first to answer was albany. "the compliments of the _albany_ office to prof. morse and mr. wood." "_utica_ office wishes to be remembered to prof. morse and mr. wood." "_auburn_ office sends compliments to prof. morse and mr. wood." "_buffalo_ sends compliments to prof. morse and mr. wood, and presents _lake erie_ to _old ocean_." "_rochester_ office sends compliments to prof. morse and mr. wood, and presents _erie canal_ to _croton aqueduct_." "_auburn_ presents _state prison_ to the _tombs_." "_syracuse_ sends compliments to prof. morse, and asks how are the yorkers." "_troy_ says, now give me a chance. compliments to prof. morse and mr. wood; and now for business, if there is any." "_utica_ asks, need we keep dark any longer?" "_troy_ answers, no. announce it to the four winds that buffalo and new york _are no longer separated--they talk to each other by lightning._" this entire dialogue occupied somewhat less than _five minutes_! * * * * * setts of thirty-six numbers of the last volume of this paper, may be had for one dollar--very cheap. any one desiring them may enclose the amount to the publishers. * * * * * advertising in london. a new and "improved" mode of advertising has been introduced in london; which is to furnish laborers, carmen, &e. with while frocks or jackets, on the backs of which are printed in large characters, the advertisements of hotels, tradesmen, &c. the wearers of the bills are generally allowed a small compensation. * * * * * deerfield bridge. the railroad bridge at deerfield, mass., is said to be a splendid affair. it is fifty feet above the traveled stage road bridge, and nearly eighty feet above the waters of the river. the piers are already erected, and nearly ready for the superstructure. * * * * * the artesian well at south boston has been sunk to the depth of nearly feet. the boring machine is worked by steam power, and progresses about feet per day. * * * * * some impudent doctor says that tight lacing is a public benefit; for it kills off the foolish girls, and leaves the wise ones for good wives and mothers. * * * * * an exchange remarks--"when we see a man kick a horse, we say at once, that he never need come to court our daughter, for he should not have her if he was worth a million." * * * * * information wanted. mr. editor,--i have a saw-mill which draws thirty-six square inches of water, under thirty feet head. i wish to build another below with only twenty feet head of water. how many square inches aperture will be required to discharge the same quantity in the same time? if some of your correspondents will give me an answer, they will much oblige me. r. c. navarino, sept. , . we shall have no occasion to depend on correspondents for the intelligence above required. thirty-six inches of aperture under thirty feet head, will admit the discharge of cubic feet of water per minute; the velocity of the water being forty-four feet per second. under twenty feet head the velocity is only thirty-six feet per second, and consequently forty-four inches aperture is required to discharge an equal quantity. _rule in hydraulics_: (never before published.) to ascertain the velocity of water issuing through an aperture under a given head: multiply the head in feet by , and the square root of the product will show the velocity in feet per second. * * * * * railroad intelligence. old colony railroad, from boston to plymouth, mass., has for some time past been in full operation, and is doing a fair business. the whole amount of the stock of the michigan central railroad--$ , , --has been taken up, and of course the enterprise will go forward. on the first day of the opening of the subscription books for the stock of the new york and boston railroad, the people of middletown took shares to the amount of $ , ; and they expect to go up to half a million. the cheshire n. h. railroad is going ahead rapidly, the grading and bridging on every part of the line being in progress. this road is to be carried over the connecticut river at or near bellows' falls. the stock of the wilton n. h. branch railroad is said to be all taken up. a general meeting of the proprietors of the st. lawrence and atlantic railway was recently held at montreal. it appears by the report of the board of directors, that , shares had been taken up, amounting to about £ , , . all parties appear to be confident that this road will be constructed and in operation at an early day. the little miami railroad having been opened to springfield, is doing a fair business, and adds important facilities to trade in that section. the directors of the new york and erie railroad are said to be "going on with it in the right way to accomplish the great object of the undertaking." contracts are already made for the construction of the road as far as the valley of the delaware. proposals for grading miles more are advertised for, which will carry the road to binghampton, miles from new york. * * * * * it is asserted that of all single marriageable ladies who reached oregon last season, two-thirds were married before the first of march. * * * * * alexandria has decided on re-annexation to virginia, by a vote of to . probably some of her citizens want to be governors and representatives. * * * * * the arrival of the new steamship southerner in charleston, hours from new york, excited much admiration. she brought passengers; and was pronounced decidedly the handsomest vessel seen in those waters. * * * * * the price of flour at buffalo, on the th inst., was $ . per barrel. corn, cents per bushel. * * * * * mr. j. b. gough, who has been for some time seriously indisposed, has nearly recovered his health, and returned north. * * * * * gold is imported from st. petersburgh to london, at the rate of $ , per month.--the mining business in russia is increasing. * * * * * the boston common council charge $ per annum for the licenses of the howard and national theatres, with the condition that spirituous liquors shall not be sold, and no female admitted unless in company with a male. * * * * * latest news: [illustration: latest news] arrival of the cambria. the steamship cambria arrived at boston on friday, the th inst., thirteen days from liverpool. from the news by this arrival, we select the following brief items:--not very interesting, but better than none. * * * * * the man henry, who lately attempted to shoot the king of france, has been tried and condemned to work in the galleys for life.--during his trial, he expressed a wish to be condemned to death, but the request was not granted. * * * * * the bank of england has reduced its rate of interest to per cent., whereby greater facilities are given to trade to counteract the depression likely to proceed from other causes. * * * * * the british ship america recently arrived from the coast of mexico and peru, liberally laden with specie, the amount whereof is stated at _six millions of dollars_, which, in silver, would make nearly two hundred and fifty tons. * * * * * the queen of spain, isabella, has decided to marry her cousin, the duke de cadiz; thus putting to rest a subject which has long agitated the circles of royalty in europe. * * * * * late news from the east furnishes the report that robberies and piracies are of hourly occurrence in the immediate vicinity of hong kong. an ordinance had been promulgated in china for the relief of debtors. * * * * * the cambria brought passengers, among whom were hon. washington irving, our late minister to spain, and the celebrated "cruikshanks," the caricaturist. * * * * * the mexican war. the latest news from mexico, and from our army, represent affairs in a most quaint and ludicrous light, with regard to the policy and movements of all parties. the average progress of the army of invasion appears to be about three miles a day, with no opposition, nor prospect of any; while the mexicans are tame as bullfrogs, showing no disposition to either fight or run. gen. parades having got sick of his job, has suffered himself to be imprisoned at the approach of santa anna, who has returned and resumed the government without opposition. mr. polk having sent an embassy, virtually asking permission to "give it up," has been refused a hearing, unless he will first withdraw our troops from the mexican territory; while the mexican army appointed to combat and conquer gen. taylor, remains at ease and content at mexico, calculating, probably, that the longer they wait, the less distance they will have to travel to encounter the yankees. whether our president will call off gen. taylor with the american troops, before they reach anywhere in particular, remains to be decided. * * * * * trade to santa fe. the trade to santa fe is said to be much greater this year than ever before. thirty-nine companies of traders have gone out this season, taking with them four hundred and thirteen wagons, which are in the charge of about eighteen hundred men. the value of the goods carried out by these traders, is estimated at nearly a million of dollars. * * * * * a large mastiff dog picked up a favorite lap dog in the upper part of the city last week, and ran off with it. he was pursued by a mob, and after a severe chase, the terrified pet was recovered and brought back rejoicing. * * * * * the scientific american. persons wishing to subscribe for this paper, have only to enclose the amount in a letter directed (post paid) to munn & company, publishers of the scientific american, new york city. terms.--$ a year; one dollar in advance--the remainder in months. _postmasters_ are respectfully requested to receive subscriptions for this paper, to whom a discount of per cent will be allowed. any person sending us subscribers for months, shall receive a copy of the paper for the same length of time, gratis. * * * * * the harbor of havana [illustration: havana harbor] our engraving represents a view of the harbor of havana, which is one of the most commodious in the world, communicating with the sea by a channel little more than half a mile in length, and from to yards wide; its depth varying from eight to ten fathoms. the harbor itself is an oblong basin, surrounded by heights which usually shelter it from the wind. havana is a place of considerable strength, and, besides the walls and ditches which surround it, the city is defended by six strongholds, called the moro, the cobanas, no. , the atares, the principie and the putna. the first and last serve to protect the entrance of the harbor, the second is a sort of citadel and the others are so placed as to cover the approaches by land. the line of fortification, embraces a sort of irregular polygon of an eliptical form, the greatest diameter of which is , yards, and the smallest , yards in extent. the entrance between the moro and putna, castles is about , yards long, and in its narrowest part yards wide. in the arsenal of the havana, there have been built ships of the line, frigates, packet ships, brigs of war, and schooners of war. the town is built on the western side of the basin, near the channel, on a kind of promontory. the suburbs, or _barrios esta muros_, cover more ground and contain a larger population than the city itself, and yet they are so intimately connected with it, that the first of the houses in the suburban street, stands on the very edge of the _glacis_. the streets are narrow, crooked, and generally unpaved, but they contain some well-built houses. there are, too, several good buildings among the churches, one of which contains the remains of christopher columbus. the other large edifices, as the palace of the government (shown to the right of the engraving,) that of the commandant of the marine, the arsenal, the post-office, and the building used for the manufacture of tobacco, are less remarkable for their architecture than for their solidity. besides these, the city contains nine parish churches; six other churches, connected with hospitals and military orders; five chapels or hermitages; the caza cuna, a foundling hospital; and eleven convents, four for women, and seven for men. the other public establishments are the university, the colleges of san carlos and san francisco de soles, the botanic garden, the anatomical museum and lecture rooms, the academy of painting and design, a school of navigation, and seventy-eight common schools for both sexes. these places of education are all under the protection of the patriotic society and the municipal authorities. the charitable institutions consist of the _caza de beneficiencia_, for both sexes, a penitentiary, a magdalen asylum, and seven hospitals--one of them contains a lunatic asylum. there are, besides, three theatres, an amphitheatre for bull fights, _plaza de toros_, and several public promenades, such as the alameda and the paseo nuevo; in turnbull's "travels in cuba," published by longman & co., london, , the city is said to contain , houses within the walls, all built of stone; and in the suburbs, , , of various materials. the number of private carriages for hire amounted, in , to , , and they are certainly now more numerous. in the same year, the population was , --the whites were , ; the free negroes, , ; the free mulattoes, , ; the negro slaves, , , and the mulatto slaves , . turnbull, speaking of the _real caza de beneficencia_, says: "girls are not admitted to the institution after years of age; and, being entirely supported there, they are completely separated from their parents and their families, until the time of their final removal from the establishment has arrived. they are taught the various branches of needle-work and dress-making, and receive such other instruction as may sufficiently qualify them for becoming domestic servants, housemaids, cooks or washerwomen. they are not suffered, by the regulations, to remain in the house after the age of twenty-one: but, before that time, it is the duty of the _junta_, or committee of management, to endeavor to procure employment for them earlier in a private family or in some house of business. should the circumstances of the parents have improved during the stay of their daughter at the institution, they are not suffered to take her away until they have paid her previous board and education at the rate of fifteen dollars a month; but if the girl herself has acquired property by inheritance, or is able to improve her condition by marriage or otherwise, independent of her parents, she is suffered to leave the house without any payment; and, in the event of her marriage to the satisfaction of the junta, a little dowry is provided for her, amounting to $ , from a fund created from prizes in the lottery, the produce of tickets presented to the institution. six such marriages had taken place, and dowries bestowed from this fond in the course of a single year." this lottery business shows the spirit of gambling so largely developed in nations of spanish descent. the mexicans are noted for it, and santa ana, who spent his exile in cuba, and recently sailed from havana for vera cruz, indulged in the propensity to a great extent. but he had two strings to his bow, and whilst playing his fighting cocks was also playing for an empire, and has won the game. how long he will hold it remains to be seen. * * * * * [illustration: humourous] humorous. a very long nose. a gentleman having put out a candle by accident one night, ordered his waiting man (who was a simple being) to light it again in the kitchen, adding--"but take care, james, that you do not hit yourself against anything in the dark." mindful of the caution, james stretched out both arms at length before him, but unluckily, a door that stood half open, passed between his hands and struck him a woful blow upon the nose. "golly gracious!" muttered he, when he recovered his senses a little, "i always heard that i had a very long nose, but i never thought it was longer than my arm!" * * * * * sol. smith. the american sentinel, speaking of "sol. smith, the lawyer, actor, preacher," &c,. remarks--"we want a few more of such men," to which a dayton (ala.) paper replies--"you'll not get them. there are none others like him. he is the first and last of his genus, a _sol_itary specimen of a strange combination of character. even in the physical way sol. will be hard to match, for he is tall as a may-pole, and crooked as a pump-handle". * * * * * the true american says that when john c. calhoun takes snuff, every man in south carolina sneezes. * * * * * a profitable hoax. recently at the copper mines on lake superior, a "greenhorn" asked some miners to show him where to dig; they offered to do it, provided he would treat to a quart of "_prairie dew_," which he did, and they set him to work under a shady tree, in mere sport. before night he struck a "_lead_," and the next sold out for $ . * * * * * reforming. "well, how are you this morning?" said one old rowdy to another. "well, sir, quite well--never was better; i'm another man, sir." "ah! then who pays those old accounts of yourself that was?" "don't remind me of my sins, i'm reformed man. i was sinful in contracting such debts, and i must now atone for my error by not paying for them." * * * * * yankee hill is most outrageously puffed by some of the albany papers. it is even insinuated that he is employed in part by a combination of tailors to cause the citizens to split their coats and other garments with laughing,--for the benefit of the trade. * * * * * isaac hill of the n. h. patriot, concludes that the new tariff law is not seriously affecting the manufacturing interests, because he lately saw two loads of machinery going into the country. he must be a sage. * * * * * some scoundrel has run away with the wife, children and furniture of a mr. reynold, residing in allegany county, leaving nothing but an empty house with the rent unpaid. really too bad. * * * * * [illustration: wrong side up] the appearance of many things and circumstances, like the above cut, depends on the view we take of them: and be it remembered that when a man's head is inverted, to him all appear _wrong side up_. hence arises most of the complaints, grumbling and murmurings, about the times, the weather, the government, the people, &c. to one who possesses, or is possessed of a malignant, peevish disposition himself, most of the conduct of others, and the times and circumstances in general, will to him appear _wrong side up_, and he will not infrequently find his own calculations _up side down_. could we at once, view each circumstance in all its different bearings, we should generally see some things that would paliate others, and thus render the whole at least tolerable: and most of the jarring and clashing in the world would thus be avoided. but by far the better way is to take of each and every thing a view the most favorable. this course is evidently peaceable, else politicians and sectarians could not so uniformly applaud every act of their favorite sect or party, and as uniformly oppose and deprecate those of their opponents. every man who habituates himself to viewing things in the most favourable light, will find this course the most conducive to his own happiness, while it contributes much to that of his neighbors and associates. look at the bright side of every thing, and hold every picture _right side up_. * * * * * importance of humility. dr. franklin once received a very useful lesson from the excellent dr. cotton mather, which he thus relates in a letter to his son:--"the last time i saw your father was in . on taking my leave, he showed me a shorter way out of the house, by a narrow passage, which was crossed by a beam over head. we were still talking, and as i withdrew, he accompanying me behind, and i turning towards him, he said hastily, "stoop, stoop!" i did not understand him till i felt my head hit against the beam. he was a man who never missed an opportunity of giving instruction; and upon this he said to me: 'you are young and have the world before you. _learn to stoop_ as you go through it, and you will miss many hard thumps.' this advice, thus beat into my head, has frequently been of use to me. and i often think of it when i see pride mortified, and misfortune brought upon people by their carrying their heads too high." * * * * * "an ambassador" is defined as a man sent abroad to lie for the good of his country. to compensate them for the wear and tear of conscience, the country allows him a larger salary than any other subordinate they employ. * * * * * _communicated_ the eureka: or journal of the national association of inventors. (we had not intended to say any thing on the subject of the "eureka" in this number, nor until the second number of the work should have been issued: but finding that a great degree of dissatisfaction exists in the minds even of those who are represented in that paper to be the supporters and conductors thereof; and having received an implied request for the insertion of the following communication, we would not refuse it, although we doubt whether the eureka will ever reach its third number, whether its contents are subjected to public criticism or not.) _mr. editor:_ i had a little curiosity to hear what the press said of this periodical; but as yet i have not seen any notice, except the brief one in your columns. as a general rule, it is inexpedient for an association to publish a periodical. instead of being an expression of the society, it almost unavoidably becomes the organ of a clique, and renders the patronage of an otherwise liberal organization subservient to private interest. in the columns of the "n. york farmer" was first advocated the formation of the n. y. state agricultural society. among the first acts of this society was the issuing of an agricultural paper at _twenty-five cents_ per annum. this was scattered over the whole country to the injury of those who had been pioneers in publishing agricultural papers. the society could not sustain it without loss. it was sold to an individual on condition that he would publish the proceedings of the society. the price was quadrupled. it was soon found that a periodical having a general circulation, could not devote much space to a local society, however noble and prosperous. necessity led to the columns of the daily press, and to the issuing of a yearly volume of transactions. this will be the result of every prosperous association. if the proceedings are worth publishing, the press will spread them over the whole face of the civilized world. a collection of the most important and well-digested papers in a yearly volume, is more in accordance with the dignity and usefulness of a national association. besides the injustice done to other periodicals previously in existence, the association adds nothing to its reputation by the undertaking. there are three or four individuals at the american institute who have a hankering for the control of a paper. it is very easy to see that the publishing of a weekly paper by the institute would be a suicidal act. all the institute has to do is to make its proceedings interesting, and the widest publicity will be given as a matter of course. it was natural to suppose that with such an array of editors, editorial committee, and of associate professors, the "eureka" would have done credit to the age, and claimed a rank, in point of literature, with other monthlies. but candor leads me to say, i do not recollect of having read a select journal with so many violations of correct writing. with the exception of two or three articles, the whole number abounds with school-boy violations of the english language. redundancy and the want of appropriateness in the use of words are the most common errors. circumlocution and want of precision are common; and in many sentences all these and other violations occur, rendering it almost impossible to guess at the meaning. independent of "_inflexibly_ in advance" on the cover, the first sentence in the announcement on the first page is an instance of ambiguity and careless construction. in the first article, on the same page, are several sentences indicating the same carelessness. the article describing hoe's cylinder press is a collection of badly-constructed sentences. if your limits permitted i would give a whole column of illustrations. the following sentences have so many faults i cannot italicise. they may serve to exercise your juvenile readers. "we intend to pursue the publication of the list hereafter, future and past; that is in our next number will appear those of august , and follow for one month; also the list for one month prior to the st of june." "a material or composition, of a very cheap character, has been invented, and hard, strong and compact as flint." "from this, streets of any grade may be formed, and in such a way as to entirely to secure a permanent and level surface to its proper grade and arch". three fourths of the sentences forming the article on dr. lewis' railroad are very faulty. "hutching's propeller. it consists of forming a set of oars, and by cams upon themselves, and a foundation-plate with cams to match, cause the oars to revolve of themselves, when the main wheel, composed of these oars, revolves." "a patent is pending for the invention of a wheel, in which mr. wm. hulme, of paterson, n. j, has made an invention." "russ's pavement, there is no doubt it will make a good road in comparison with our present streets, as far as surface goes; but we must confess our incredulity of the entire success of this plan. we do not like the ideal method of getting at the water-pipes, &c. of the city." the report on rider's iron bridge is by another and different pen. i will pass by "_protracted_ from beneath upwards," &c., and give a few more quotations. "inventors scarcely ever receive the compensation due their however distinguished merit, either pecuniary or laudatory. the originators or first conceivers of the most momentous plans of utility and comfort are oftenest the most grossly neglected and overlooked." "shortly after these details reached the u. states, by professor s. f. b. morse, of new york, who was at the time of the discovery residing in paris." "this committee give their services for the promotion of good to the cause of invention and science, without any consideration other than this." "almost all other branches of knowledge have their magazines and journals, and other means of diffusing information, so that in their departments hardly a desideratum is left to be supplied; while the inventor, as such, has almost no channel through which he may legitimately appear before the public." "an editorial committee was accordingly appointed for the supervision of this department, and to whose inspection all matter of the journal, previous to publication, will be submitted." all the previous articles have been descriptive. we now come to our argumentative, on novelty in inventions. the reasoning powers of the writer may be learned from the following: "thus we conclude that the _novelty_ of _an invention_ consists in making something 'useful to society,' and that in an original and novel way, so as to embody the great principle of invention." or, as far as the writer has informed us, the novelty is the useful, the useful is the original and novel, and the original and novel are the great principle, and the great principle is the novelty or something else. "we offer an explanation, not an apology for the want of a more full variety of scientific matter." "fisher's magazine publishes a complete list, comprising the railroads of the u. states, as far as they are completed, and as far as particulars are known." "the french government has patronized an exploration of the island of cyprus, for the purpose of exploring its architectural remains." under the head of "editors' table," i subjoin the principal and most important sentence: "in this department we have but little room, and in this case it is, perhaps, well we have little, as it is seldom much in the way of articles for notice, are placed before an editorial corps before the appearance of the first number." with the exception of three or four articles, the whole number is discreditable to the national association of inventors. a second number should not appear until the editors have had the benefit of at least one term in the preparatory school of columbia college. sept. , . s. f. * * * * * a heron measuring over six feet from tip to tip of his wings, and nearly four feet from beak to toe, was lately captured in whately, mass. his beak was six inches in length. * * * * * the print works of east greenwich, r. i. engaged in printing mousseline-de-laines, are preparing to close business and shut up. * * * * * worthy of attention.--"we wonder at the foolish practice of the chinese, in the uncomfortable form and pressure of their shoes, while at the time, the construction of our own is often but little better. if shoes were made in the shape of our feet so as to exert an equal pressure on every part, corns and bunions would never exist."--[n. y. organ, sept. , . [symbol: right index] the above truthful and judicious remarks emanating from the able editors of the above valuable journal, should strongly present itself to the minds of every person having an eye to the comforts of life. to those who have given a trial of the superior boots and shoes manufactured with dick's patent elastic metallic shanks, information would be needless; for they could not be induced to purchase elsewhere. but we would respectfully ask attention of the entire boot and shoe wearing community, to call at nassau street, being assured that it gives the proprietors great pleasure to impart every information for the ease and comfort of the understanding, and also with regard to their entirely new mode of taking the measurement of the foot, to give an equal pressure on every part. * * * * * advertisements. [symbol: right index] this paper circulates in every state in the union, and is seen principally by mechanics and manufacturers. hence, it may be considered the best medium of advertising, for those who import or manufacture machinery, mechanics tools, or such wares and materials as are generally used by those classes. the few advertisements in this paper are regarded with much more attention than those in closely printed dailies. advertisements are inserted in this paper at the following rates: one square, of eight lines one insertion, $ . " " " " " two do., . " " " " " three do., . " " " " " one month, . " " " " " three do., . " " " " " six do., . " " " " " twelve do., . terms:--cash in advance. general agents for the scientific american. new york city, geo. dexter. " " " wm. taylor & co. boston, messrs. hotchkiss & co. philadelphia, messrs. colon & adriance. local agents albany, peter cook. baltimore, md., s. sands. cabotville, mass., e. f. brown. hartford, ct., wm. woodward. lynn, mass., j. e. f. marsh. middletown, ct., wm. woodward. norwich, ct., safford & parks. new haven, ct., e. downes. new bedford, mass., wm. robinson & co. newark, n.j., j. l. agens. patterson, n.j., l. garside. providence, r. i., h. & j.s. rowe. springfield, mass., wm. b. brocket. salem, mass., s. chandler. troy, n.y., w. smith. taunton, mass., w. p. seaver. worcester, mass., s. thompson. travelling agents v. d. david, john stoughton, john murray, sylvester dierfenorf. city carriers clark selleck, squire selleck, nathan selleck. persons residing in the city or brooklyn, can have the paper left at their residences regularly, by sending their address to the office, fulton st., nd floor. * * * * * gold pens!!--in consequence of the increased facility afforded by machinery for the manufacture of my gold pens, i am enabled to furnish them to the trade, at a much less price than they have heretofore obtained them through my agent. those purchasing direct of the manufacturer will have the double advantage of the lowest market price, and the privilege of returning those that are imperfect. in connection with the above, i am manufacturing the usual style of penholder, together with pencil. all orders thankfully received, and punctually attended to. a. g. bagley. sept . * broadway. n. y. * * * * * sherwood's magnetic machine,--is warranted to be greatly superior to every other manufactured, by whatever imitations or pretensions foisted upon the public. no premium has ever been obtained over this machine at the american or any other institute, as has been falsely represented. it imparts the magnetic forces more continuously, with less violence to the sensations of the patient, and with more permanent efficacy, than any other invented, while the cures it has actually effected are incomparably more numerous. it is compactly fitted, together withs it batteries, wires and other appliances in neat cases, of several sizes, and powers, at $ , $ , $ , and $ each. each case is accompanied with a manual, (eighth edition, pp. , vo.) in the english or french language, according to order, containing specific direction for the new method of using the instrument, and which alone can render it effectual. h. h. sherwood, m.d. chambers st. sept. to * * * * * * general patent agency.--the subscriber has established an agency at his warehouse, platt street, new york, for the protection and general advancement of the rights and interests of inventors and patentees. the objects of this agency are more particularly to aid and assist inventors and patentees in effecting sales of their inventions and of goods and wares made therewith--and also for the sale and transfer of patent rights. arrangements have been made with a lawyer familiar with the patent laws, who will attend to the legal branch of the business upon reasonable terms. satisfactory references will be given. applications may be made to the undersigned personally, or by letter, post paid. samuel c. hills - dv * general patent agent. * * * * * engraving on wood. neatly and promptly executed at the office of the scientific american, fulton st, three doors from the sun office. designs, drawings of all kinds for patents, &c., also made, as above, at very low charges. * * * * * copper smith!--the subscriber takes this method of informing the public that he is manufacturing copper work of every description. particular attention is given to making and repairing locomotive tubes. those at a distance, can have any kind of work made to drawings, and may ascertain costs, &c., by addressing l. r. bailey cor. of west and franklin sts., n. y. n. b.--work shipped to any part of the country. to dv * * * * * * black lead pots!--the subscriber offers for sale, in lots to suit purchasers, a superior article of black lead pots, that can be used without annealing. the price is low, and founders are requested to make a trial. samuel c. hills, to ndv patent agent, platt street. * * * * * electricity. smith's celebrated torpedo, or vibrating electro magnetic machine--this instrument differs from those in ordinary use, by having a third connection with the battery, rendering them much more powerful and beneficial. as a curious electrical machine, they should be in the possession of every one, while their wonderful efficacy as a medical agent, renders them invaluable. they are used with extraordinary success, for the following maladies. rheumatism--palsy, curvature of the spine, chronic diseases, tic-doloureaux, paralysis, tubercula of the brain, heart, liver, spleen, kidneys, sick-headache. toothache--st vitus dance, epilepsy, fevers, diseases of the eye, nose, antrum, throat, muscles, cholera, all diseases of the skin, face, &c. deafness--loss of voice, bronchitis, hooping cough. these machines are perfectly simple and conveniently managed. the whole apparatus is contained in a little box inches long, by wide and deep. they may easily be sent to any part of the united states. to be had at the office of the scientific americcan, fulton st, nd floor, (sun building) where they may be seen in operation, at all times of the day and evening. * * * * * the ball of the bears. as stanilaus augustus, the last king of poland, was a tool of russia, and did not enjoy any consideration, the polish grandees played him many tricks. prince radziwill came to court in a carriage drawn by six wild bears;--the horses of course, were extremely frightened; in consequence of which, some accidents happened. the king pointed out to the prince the impropriety of his conduct. radziwill added, that the bears were not cross, as whip, gold, and patience can put in order every thing; he added also, that, sometimes the ace beats the king at cards, and paid liberally the damages. after some time, he gave a splendid party, to which he invited all the ambassadors, and all the leading personages in poland, and displayed extraordinary luxury. the dancing was kept up in several drawing rooms. after the supper, he conducted a select parly to a separate apartment--where, to their astonishment, they found four girls of uncommon beauty, richly dressed, in company not with four gentlemen, but with four enormous bears!--which, after the first outbreak of music, began to dance with the girls all the figures of french quadrilles, with the utmost accuracy, and with as much ease as if they were highly educated gentlemen. at first the guests were alarmed; but, seeing the extra ordinary tameness of the beasts, struck with amazement, they seemed to have been pleased with this extraordinary sight. after the dance was over, their bear-ships conducted themselves with the utmost propriety, and, at a sign from the keeper, each of them made a bow to his lady, and withdrew to another room. for some time, nothing was talked of at warsaw but that singular ball. * * * * * all is not gold that glitters. a lady, at a ball lately given in calcutta, attracted the attention of all, and excited the jealousy of many, in consequence of the splendor and brilliancy which her diamonds shed upon her person and all around her. at length that curiosity which is the moving spring of woman's actions, could be no longer resisted by her female admirers, who at the close of the ball, instituted a rigid examination of the nature of those incomparable brilliants, when, to their astonishment, they found that they were no more or less than so many fire flies, which the envy of the ball-room had secured in gauze bags, and which as she moved about, fluttered, and thus threw out their varied brilliant hues. * * * * * the odd fellows procession to the dedication of their new hall at philadelphia, says our exchanges "_came off_ on thursday". we suppose the procession "came off" this way, as we saw a part of it passing through this city. * * * * * a young lady by the name of emma d. tower, sixteen years of age, has been missing from her parents and home in providence, r. i., since the th. her parents are distressed with anxiety to find or hear of her. * * * * * [illustration: curious arts] painting in imitation of rose-wood. (by the particular request of a "mechanic" in cherryfield, me.)--in this art the process is various according to the circumstances, and the ground on subjects to which it is applied. in painting common chairs, the ground is prepared by a coat of paint composed of ivory black and rose-pink,--equal quantities, ground in a mixture of equal parts of linseed oil, drying japan and spirits of turpentine.--when this is dry, the graining color, consisting of three parts of rose-pink with one of vermillion, ground in a mixture of oil, japan and spirits of turpentine, is applied with a common flat graining brush. fancy boxes and cabinet furniture are painted by a different process, by which a better imitation is produced. the ground is prepared by one or more coats of white lead changed two or three shades with yellow ochre. when dry, a thin staining of burnt terra-de-sienna ground in water, containing a very little sugar or gumarabic is laid on the work, and while this continues moist and flowing, the graining is applied. the graining should consist of a mixture of black and rose pink, ground in the staining compound. this must be varnished when dry, with copal varnish. some prefer, however, to grind the staining and graining in oil, diluted with spirits of turpentine. the learner must have some sample pieces of varnished rosewood before him when graining. * * * * * india rubber. the substance called india rubber, or caoutchouc, was not known in europe until the beginning of the eighteenth century. it was originally brought as a great curiosity from south america. europeans continued ignorant of its origin until a deputation of the french academicians undertook a voyage to south america in , for the purpose of obtaining the correct admeasurement of a degree of the meridian. these philosophers did not confine their attention to the one great object of their pursuit, but among other interesting discoveries made themselves acquainted with that peculiar substance--caoutchouc. these academicians discovered at emeralds, in brazil, trees called by the natives _heve_, whence flowed a juice, which, when dried, proved to be what is called india rubber. the _heve_ was also found growing in cayenne, and on the banks of the amazon river. it has since been discovered that caoutchouc may be obtained from another species of tree growing in south america, called _jatropha elastica_. if these trees are punctured, a milky juice flows out, which, on exposure to the air, thickens into a substance of a pure white color, having neither taste nor smell. the hue of the caoutchouc of commerce is black in consequence of the method employed in drying it. the usual manner of performing this operation is to spread a thin coating of the milky juice upon the moulds made of clay, and fashioned into a variety of figures. these are then dried by exposure to the heat of a smoke-fire: another layer is then spread over the first, and dried by the same means; and thus layer after layer is put on, until the whole is of the required thickness. while yet soft it will receive and retain any impression that may be given to if on the outside. when perfectly dry the clay within is broken into small fragments by percussion, and the pieces are drawn out through the aperture which is always left fur the purpose. the common bottle of india rubber, therefore, consists of numerous layers of pure caoutchouc, alternating with as many layers of soot. the natives of those parts of south america to which these trees are indigenous, convert the juice to a variety of purposes. they collect it chiefly in the rainy season, because, though it will exude at all times, it flows then most abundantly. boots are made of it by the indians, through which water cannot penetrate; and the inhabitants of quito prepare a kind of cloth with it, which they apply to the same purposes as those for which oil-cloth or tarpaulin, it used here. this, no doubt, is similar to the cloth now prepared with this substance in america, the use of which yields so many important advantages.--_youths' gazette_. * * * * * communication on atmospheric resistance. the following letter has been on hand several weeks, but deferred on account of a constant press of matter by which the limited space in our former small sheet was crowded. our respected correspondent has consented to excuse the delay. providence, ---- . _friend porter_: in january last, i addressed a few lines to you, asking information in regard to an article entitled atmospheric resistance, in the new york mechanic, of december , . in your answer, you say if the full surface is , square feet to each wing, (which makes , square feet,) only about half of one horse power would be required to sustain this weight, and i understand you, virtually to say, that they must be ten times as large, in order that the strength of one man be sufficient to work this and elevate himself together with the apparatus, if it were not too heavy. now, this makes , square feet. this is rather more than feet square: rather large sized wings. one would suppose that they might lift rather heavy, if they were very light, being by feet each. now, to me this is entirely incomprehensible, and i should like an explanation, if this calculation is correct, how it is that an eagle which sometimes weighs nearly thirty pounds, can elevate himself, with so much ease, and even carry with him nearly his own weight, using a pair of wings, which if they were five feet long and two feet wide each, would make but twenty feet of surface. thus, you will see, is no where in proportion to the weight even of the eagle alone, (which we will suppose to weigh twenty pounds,) that the wings bears to the pounds, while on the other hand, it is near in proportion to the surface of the wings of a pidgeon and its weight. nor can i comprehend why it would require so much power, the eagle though he exerts himself considerable in rising, no doubt, does not seem to use power any where in the proportion that you have thought would be required supposing the wings to be made in the same proportion to the pounds that his wings are to his weight, his beats are not so quick but what they can be very easily counted. by answering, you will much oblige, your friend, yankee. in answer to the foregoing, we would remind our correspondent, that in his former communication, he proposed a limited weight of apparatus, and in our answer, it was far from our intention to allow an additional weight on account of the requisite extent of surface. with regard to the philosophy of the flight of the eagle, it must be borne in mind that atmospheric resistance is as the square of the velocity _downward_ and the only way in which the phenomenon of the flight of the eagle can be reconciled with the laws of mechanical science as established by experiment, is by supposing the velocity of the wing downward to be equal to feet per second, whereby a resistance would be encountered equal to pounds per square foot of surface to the wings. it is a fact, however, that kites, and hawks are often seen to continue suspended in the air several minutes without any apparent motion of the wings; but by what law or theory the feat is accomplished, natural philosophy has ventured no other conjecture than that the bird is endowed with the faculty of suspending occasionally its ordinary subjection to the laws of gravity. if any observing theorist will give any more rational conjecture on the subject, we should be glad to have him examine it. * * * * * it is proposed and urged by the papers in several states, to have a thanksgiving day throughout the union, on the th of november. * * * * * "as dull as a hoe," is a very common phrase, and implies that hoes are necessarily or ordinarily dull. but it is advisible for farmers to keep their hoes sharp, as they regard a saving of labor. * * * * * [illustration: the conical windlass] the conical windlass. various methods have been heretofore described, for raising heavy bodies, or producing for other purposes, a great force,--usually miscalled power--by the application of a comparatively small force: but no method is known, more unlimited in its effect, or more simple in construction; than the conical windlass. it consists of a simple horizontal windlass, with a crank at one end, as shown in the engraving. the windlass is made in a conical form, being a little larger at one end, than at the other; and if the friction of its bearings be relieved by the ordinary friction rollers, it will so far multiply the force applied, as to break a double inch-rope, by the power of one man at the crank. an endless rope, or one of which the two ends are spliced together, is passed five or six times round the small end of the windlass, and down under a single pulley below: then, as the windlass is turned by the crank, the rope is constantly given off from one part, while the circumference is greater. now it is plain, that if the windlass is one-fifth of an inch larger in circumference, at the point at which the rope is taken up, than at the place where it is given off to the pulley, that whatever may be appended thereto, will be raised one tenth of an inch by each revolution then, if we suppose the crank lever to be fifteen inches, the handle will travel about inches, in each revolution, which gives a power, or increase of force, of to one. therefore, if pounds of power be applied to the crank handle, it will be sufficient--minus friction--to raise a weight of , lbs. the only inconvenience in this apparatus, and which prevents its coming into more general use, is, that it is too limited in the extent of its motion, in consequence of the travelling of the rope from one end of the windlass to the other. thus, if the windlass be but twenty-five inches long, and the rope one inch in diameter, it will admit only twenty revolutions, without renewing. yet, in many cases, in which an article in required to be raised, or moved but a few inches, the conical windlass will be found preferable to any other method. * * * * * requisite strength of steam boilers. our correspondent s. b. cannot comprehend that the strength of iron for a cylindrical boiler should be in direct proportion to the diameter thereof, in order to sustain an equal pressure per square inch; wherefore, we must reason with him on the long scale. the cohesive strength of good iron is , lbs. per square inch; and of course, a strip of boiler-iron plate / th inch thick will sustain lbs. if a boiler made of thin iron is inches in diameter, or inches in circumference, each inch of its length will contain square inches, and either half thereof will contain inches, and as the pressure on this portion is sustained by at least two inches of width of plate,--one inch on each side,--it follows that it will sustain a pressure of at least lbs. per square inch, in the direction of circumference. if the diameter is double, the number of square inches will be double, and will require double the thickness to sustain equal pressure. with regard to the pressure endwise, the area of a cylinder head inches in diameter is inches, and the strength of the inches of circumference would be sufficient to sustain , lbs., which, divided by the area, is , lbs. per square inch. if the diameter is inches, the circumference being , would sustain a pressure endwise of lbs. per inch. thus it will be seen that if the cylinder were even feet in diameter, the iron would better sustain the pressure on the head that on the periphery. with regard to the requisite strength of the cylinder's head, if they are made in a semi-spherical convex form, they will require no more thickness of plate than the cylinder: but if they consist of plane disks, the thickness thereof should bear the same proportion to that of the periphery that the area in square inches does to three times the circumference. but in general, no other rule is observed for the thickness of the heads, than to make them extravagantly heavy, without much regard to theoretic calculation. * * * * * bagley's gold pens. do our readers wish to hear any thing more about them? if so, they have only to inquire of any one of the many thousands of writers who have used these pens six months or more, and can hear the fact attested, that these are decidedly the cheapest pens (at $ ) that can be any where found. mr. bagley has recently patented a neat, elegant, and excellent improvement in the pen-holder, which "takes the shine off" all precedents. should our readers find a real good article in this paper, they may know it was written with one of bagley's pens. nuf ced. * * * * * the humming bird. a gentleman who resided some time on one of the west india islands informs us that while he was once travelling along the bed of a deep ravine overhung with thick vines, he was actually startled by the immense numbers of humming birds which hovered over and about him. they hovered about him as if actuated by curiosity alone. they were of various kinds and colors, some of them being nearly as large as sparrows, while others were but little larger than a bee. some were of a dingy green, or a light brown, while others seemed gaudily arrayed in plumage as brilliant and variegated as the rainbow. they would approach within arms length of his face, and pausing in their flight, with their little wings, in rapid motion, would stare at him as if they wondered what possible business he could have in those remote wilds; but they exhibited no symptoms of terror, not having been taught by experience to fear the cruelty of man. * * * * * the new york scientific american: _published weekly at_ _fulton street_., (_sun building_,) _new york_. by munn & company. the scientific american is the advocate of industry and journal of mechanical and other improvements: as such its contents are probably more varied and interesting, than those of any other weekly newspaper in the united states, and certainly more useful. it contains as much interesting intelligence as six ordinary daily papers, while for _real benefit_, it is unequalled by any thing yet published. each number regularly contains from three to six original engravings, illustrated by new inventions, american and foreign,--scientific principles and curiosities,--notices of the progress of mechanical and other scientific improvements, scientific essays on the principles of the sciences of mechanics, chemistry and architecture,--catalogues of american patents,--instruction in various arts and trades, _with engravings_,--curious philosophical experiments,--the latest rail road intelligence in europe and america,--valuable information on the art of gardening, &c. &c. this paper is especially entitled to the patronage of mechanics and manufacturers, being devoted to the interests of those classes. it is particularly useful to farmers, as it will not only apprise them of improvements in agricultural implements, but instruct them in various mechanical trades, and guard against impositions. as a family newspaper, it will convey more useful intelligence to children and young people, than five times its cost in school instruction. being published in quarto form, it is conveniently adapted to preservation and binding. terms.--the scientific american is sent to subscribers in the country at the rate of $ a year, one dollar in advance, the remainder in months. persons desiring to subscribe, have only to enclose the amount in a letter, directed to munn & company, publishers of the scientific american, new york. [symbol: right index] specimen copies sent when desired. all letters must be post paid. transcriber's notes: [symbol: right index] is used where the text had a picture of a hand with the index finger pointing right. obvious typographical errors have been corrected without comment, except in those articles where they were intentionally presented. [transcriber's notes: this is paper from the smithsonian institution united states national museum bulletin , comprising papers - , which will also be available as a complete e-book. the front material, introduction and relevant index entries from the bulletin are included in each single-paper e-book. note that several figures in this paper consist of two images separated from each other in the original layout, with separate labels. these separate labels are preserved in this text only version. typographical errors have been corrected as follows: p : "the _simon & jude_, later called _invention i_" (was "latter"). p : "its importance is that it..." (was "is that is"). index: "emmet, ----, " (was emmett).] smithsonian institution united states national museum bulletin [illustration] smithsonian press museum of history and technology contributions from the museum of history and technology _papers - _ _on science and technology_ smithsonian institution · washington, d.c. _publications of the united states national museum_ the scholarly and scientific publications of the united states national museum include two series, _proceedings of the united states national museum_ and _united states national museum bulletin_. in these series, the museum publishes original articles and monographs dealing with the collections and work of its constituent museums--the museum of natural history and the museum of history and technology--setting forth newly acquired facts in the fields of anthropology, biology, history, geology, and technology. copies of each publication are distributed to libraries, to cultural and scientific organizations, and to specialists and others interested in the different subjects. the _proceedings_, begun in , are intended for the publication, in separate form, of shorter papers from the museum of natural history. these are gathered in volumes, octavo in size, with the publication date of each paper recorded in the table of contents of the volume. in the _bulletin_ series, the first of which was issued in , appear longer, separate publications consisting of monographs (occasionally in several parts) and volumes in which are collected works on related subjects. _bulletins_ are either octavo or quarto in size, depending on the needs of the presentation. since papers relating to the botanical collections of the museum of natural history have been published in the _bulletin_ series under the heading _contributions from the united states national herbarium_, and since , in _bulletins_ titled "contributions from the museum of history and technology," have been gathered shorter papers relating to the collections and research of that museum. the present collection of contributions, papers - , comprises bulletin . each of these papers has been previously published in separate form. the year of publication is shown on the last page of each paper. frank a. taylor _director, united states national museum_ contributions from the museum of history and technology: paper fulton's "steam battery": blockship and catamaran _howard i. chapelle_ surviving designs for floating batteries controversial descriptions copenhagen plans history of double-hull craft sail and inboard plans reconstructing the plans appendix [footnotes] [index] [illustration: figure .--scale model of fulton's _steam battery_ in the museum of history and technology. (smithsonian photo p- -f.)] _howard i. chapelle_ fulton's "steam battery": blockship and catamaran _robert fulton's "steam battery," a catamaran-type blockship, was built during the war of . until recently, not enough material has been available to permit a reasonably accurate reconstruction of what is generally acknowledged to be the first steam man-of-war._ _with the discovery, in the danish royal archives at copenhagen, of plans of this vessel, it is now possible to prepare a reconstruction and to build a model._ _this article summarizes the history of the vessel, describes the plans and the reconstruction, and also evaluates its design with particular attention to the double-hull construction._ the author: _howard i. chapelle is curator of transportation in the smithsonian institution's museum of history and technology._ the identity of the first steam man-of-war has been known for many years, and a great deal has been written and published on the history of this american vessel. until recently, the only available drawing of the ship has been a patent drawing made for robert fulton. this does not comply with contemporary descriptions of the steamer and the drawing or plan is out of proportion with the known dimensions. the lack of plans has heretofore made it impossible to illustrate the vessel with any degree of precision, or to build a scale model. the discovery in of some of the plans of this historic ship in the danish royal archives at copenhagen now makes possible a reasonably accurate reconstruction of the vessel and also clarifies some of the incomplete and often confusing descriptions by contemporary writers. of the numerous published accounts of the ship that are available, the most complete is david b. tyler's "fulton's steam frigate."[ ] a contemporary description of the vessel by the british minister to washington, - , stratford canning, was published by arthur j. may.[ ] in _naval and mail steamers of the united states_, by charles b. stuart,[ ] and _the steam navy of the united states_, by frank m. bennett,[ ] the history of the ship and some descriptive facts are given. stuart, in an appendix, gives in full the report of the supervisory committee (set up to administer the building contract). tyler and stuart, and the committee report are the principal sources from which the following summary of the ship's history is drawn. [text of illustration: plate n^o. . "demologos" figure ^st. _transverse section a her boiler. b the steam engine. c the water wheel. e e her wooden walls feet thick, diminishing to below the waterline as at f.f draught of water feet d d her gun deck_ _scale / inch= foot_ waterline _scale / inch= foot_ figure ii^d. _this shews her gun deck, feet long feet wide, mounting guns. a the water wheel_ figure iii^d _side view_ _scale / inch= foot_ robert fulton _november ._ _s m^c elroy del._ _"stuart's naval & mail steamers u.s."_ _sarony & major. eng. n.y._] [illustration: figure .--"demologos," a wood engraving based on the sketch which robert fulton showed to president madison in . this wood engraving appears as plate in charles b. stuart's _naval and mail steamers of the united states_, and illustrates the section on naval steamers, from which the account "the demologos; or, fulton the first," is here reproduced (pp. - ). stuart obtained the sketch, assumed to have been made for fulton's patent on the design of the _steam battery_, from the files of the u.s. navy department.] on december , , robert fulton invited a group of friends--prominent merchants, professional men and naval officers--to his home in new york city and there presented a proposal for a project of great local interest. at that time the war of was in its second year and the economic effect of the british naval blockade was being felt severely. the blockade cut off seaborne trade and posed a constant threat of attack upon new york and other important ports, particularly baltimore. to defend the ports, it had been proposed to build mobile floating batteries or heavily built and armed hulks with small sailing rigs, but the high cost of these and their doubtful value in helping to break the blockade, compared to the value and action of a very heavy, large frigate, or a -gun ship, caused authorities to hesitate to proceed with the construction of any blockships or floating batteries. fulton's proposal concerned a floating battery propelled by steam power. he believed that steam propulsion not only would give it effective maneuverability with no loss of gunpower, but also would allow a successful attack upon the royal navy blockading ships during periods of protracted calm, when sailing men-of-war were nearly helpless. the blockaders then could be attacked and picked off, one by one, by the heavily armed steamboat. among those present at the meeting was major general henry dearborn, a leading citizen and soldier who was later to become noted in american political history. the first step taken during this meeting was the founding of the coast and harbor defense company with dearborn as president, fulton as engineer, and thomas morris as secretary. next, a committee was established to raise funds from federal, state, and new york city governments as well as from individual contributors to build the battery. the members of this committee consisted of general dearborn, commodore stephen decatur, u.s.n.; general morgan lewis; commodore jacob jones; u.s.n.; noah brown, shipbuilder; samuel l. mitchill; henry rutgers; and thomas morris. the committee proved cumbersome and was reduced to general lewis, issac bronson, henry rutgers, nathan sanford, thomas morris, oliver wolcott, and john jacob astor. known as the coast defense society and with the name of _pyremon_ given the ship in prospectus, they attempted, unsuccessfully, to raise funds privately. the estimated sums to build a battery feet long, with a -foot beam, capable of a speed of mph, and carrying long guns ( -pdr.), was $ , . fulton, still the chief engineer, in an effort to interest the federal government, built a model of the proposed vessel and submitted it to some prominent naval officers--commodore stephen decatur, jacob jones, james biddle, samuel evans, oliver perry, samuel warrington, and jacob lewis. all gave their support to the society in a written statement and this recommendation proved helpful to the project in congress and in the navy department. in the process of passing a bill which went to the senate naval affairs committee calling for $ , for the construction of the floating battery, the sum was raised to $ , , for the construction of "one or more" floating batteries and passed on march , . to supervise the start of construction, the coast defense society appointed a committee consisting of dearborn, wolcott, morris, mitchill, and rutgers, with fulton as engineer, and a model and drawing of the proposed vessel was submitted to the patent office. the secretary of the navy, although supporting the project, delayed action until he had weighed the importance of the batteries in relation to other war needs, for at this time the naval shipbuilding program on the great lakes was considered of prime importance. he also raised some technical questions concerning the design of the batteries, which fulton answered with a description of the vessel as feet on deck, feet on the keel, feet beam (each hull to have a -foot beam and the "race" between to be feet wide), draft or feet loaded, and the intended speed was to be - / to mph. the ship was to carry long guns ( -pdr.), the engine was to be hp, and the total cost, $ , . in his letters to the secretary of the navy, fulton stated that adam and noah brown would build the hull for $ , and that he would build the engine, machinery and boilers for $ , , a total of $ , . he intended to have the boilers, valves, fastenings, and air pumps of brass or copper, which would raise the machinery costs percent above that of stationary engines and boilers then in use. on may , , the secretary of the navy authorized the coast defense society and its committee to act as navy agents and to enter into the contracts required to build a vessel, and to draw on the navy storekeepers or navy yard commandants for such stores or articles on hand needed for construction. the contracts were prepared and the committee now was officially empowered to act for the society, with rutgers, wolcott, morris, dearborn, mitchill, and fulton. on june , dearborn asked the navy department for $ , advance, for work had started. on the th, he informed the secretary that he had been ordered to assume command of the defenses of boston and that rutgers had been appointed chairman of the construction committee in his place. it is apparent that the navy department was pressed for funds, due to the very extensive shipbuilding programs on lakes erie, ontario, and champlain in addition to the seagoing vessels being built in some of the coastal ports. this was certainly one cause for the secretary of the navy's reluctance to carry out the requirements of the bill passed by congress immediately after its signature and, also, this reluctance caused the supervisory committee much embarrassment in its administration of the contract. another factor which caused difficulty in the administration of the contract was the position of adam and noah brown. the brothers were deeply involved in the shipbuilding program on the lakes, in which they were associated at times with henry eckford. the browns constructed a blockhouse, shops, and quarters at erie; in addition to perry's two brigs and five of his schooners, they also built some of the lake ontario vessels and, later, the _saratoga_ on lake champlain. in their new york yard, whose operation continued throughout the war, they built some large letter-of-marques: the _general armstrong_, _prince de neufchatel_, _zebra_, _paul jones_, and some smaller vessels. they also cut down the -decked, merchant ship _china_ into a single flush-deck letter-of-marque, renamed _yorktown_; and they had a contract to build the sloop-of-war _peacock_. it is remarkable that the browns could undertake and complete so much work between and and still be able to build the steam battery in a very short time. with the contracts in order, the browns began building. the keels of the battery were laid june , . it is apparent that the browns prepared the original hull plans, undoubtedly before the building authority was obtained. the vessel required only about four months to build; she was launched october , , at a.m. this was an excellent performance, considering the size of the vessel, the amount of timber required and handled in her massive construction, and the other work being done by the builders. during the ship's construction, sightseers were a nuisance and finally guards had to be obtained. during the building of the steam battery, work had to be practically stopped on the sloop-of-war _peacock_ at one period after she had been partially planked. there were difficulties in obtaining metalwork for the vessel during her construction, due to the blockade and the demand for such material for other shipbuilding at new york. on november , , the ship was towed from the browns' yard on the east river by fulton's _car of neptune_ and _fulton_, each lashed to the sides of the battery, and taken to fulton's works on the north river. there fulton supervised in person the completion of the vessel and construction of her machinery. undoubtedly only a little of his time was required in inspection of the browns' work on the battery, for the shipbuilders had been closely associated with fulton throughout the life of the project and were fully capable as ship designers. the work on the machinery was another matter, however, for men capable of working metal were scarce and few workmen could read plans. fulton had some of the work done outside of his own plant, particularly the brass and copper work (mostly by john youle's foundry). as a result, fulton was required to move from plant to plant, keeping each job under almost constant observation and personally supervising the workmen. the equipment then available for building a large engine was inadequate in many ways. the large steam cylinder presented a problem: it had to be recast several times and some of the other parts gave trouble, either in casting or in machining and fitting. [illustration: figure .--scale model of _steam battery_, showing double hull, in the museum of history and technology. (smithsonian photo p- -d.)] guns for the battery were another problem. only long guns ( -pdr.), were available at the navy yard. the secretary of the navy promised some captured guns then at philadelphia. because of the blockade, these had to come overland to new york. the captured guns thus obtained were probably english, part of the cargo of the british ship _john of lancaster_ captured by the frigate _president_ early in the war. apparently guns were obtained this way; only were obtained from the navy yard. in july the supervising committee carried out some experimental damage studies, in which a -pdr. was fired at a target representing a section of the topsides of the battery. drawings of the result were sent to the secretary of the navy. further problems arose over the delays of the government in making payments: the banks discounted the treasury notes, so the committee members had to advance $ , out of their own pockets. there was fear that british agents might damage the vessel, and although the project was undoubtedly known to the british, no evidence of any act of sabotage was ever found. captain david porter was assigned to the command of the battery in november, and it was upon his request that the vessel was later rigged with sails. with the _steam battery_ approaching completion, the secretary of the navy became more enthusiastic and the construction of other batteries of this type was again proposed. captain stiles, a baltimore merchant, offered to build a steam battery, the hull to cost $ , ; the entire cost of the vessel, $ , , was raised in baltimore and the frames of a battery erected. another battery was projected at philadelphia and the secretary of the navy wanted one or more built at sackett's harbor, but naval officers and fulton objected. a bill put before congress to authorize another half million to build steam batteries passed the first reading january , , went to the house february , , but the end of the war prevented any further action on it. on february , , fulton died. he had been to trenton, new jersey, to attend a hearing on the steamboat monopoly and, on the way back, the ferry on north river was caught in the ice. fulton and his lawyer, emmet, had to walk over the ice to get ashore. on the way, emmet fell through and fulton got wet and chilled while helping him. after two or three days in bed fulton went to his foundry to inspect the battery's machinery causing a relapse from which he died. this resulted in some delay in completing the machinery and stopped work on the _mute_, an -foot, manually propelled, torpedo boat that fulton was having built in the browns' yard. it was decided to suspend work on the baltimore battery after an expenditure of $ , , but the new york battery was to be completed to prove the project was practical. the final payment of $ , was made four months after it was requested. charles stoudinger, fulton's foreman or superintendent, was able to complete and install the ship's machinery. on june , , the vessel was given a short trial run in the harbor with stoudinger and the navy inspector, captain smith, on board. this trial revealed the need of some mechanical alterations; sails were not used, and it was found she could stem the strong tide and a fresh headwind. the vessel also was visited by the officers of french men-of-war at anchor in the harbor. on july , , she was given another trial. she left fulton's works at corlear's hook at a.m., ran out to sandy hook lighthouse, bore west and returned, a total of miles under steam, reaching her slip at : p.m. she was found to steer "like a pilot boat." this prolonged trial revealed that the stokehold was not sufficiently ventilated and more deck openings were required. the windsails used in existing hatches were inadequate. the paddle wheel was too low and had to be raised inches, and there were still some desirable modifications to be made in the machinery. on september , , she was again given a trial run. all alterations had been made, including the addition of hatches and raising the paddle wheel, and her battery was on board with all stores, supplies, and equipment. she had long guns ( -pdr.), mounted on pivoted carriages, and now drew feet inches. on this day she left her slip at : a.m. and went through the narrows into the lower bay, where she maneuvered around the new frigate _java_ at anchor there. the battery then was given a thorough trial under steam and sail and, with the ship underway, her guns were fired to see if concussion would damage the machinery. the vessel was found to be a practical one, capable of meeting the government's requirements in all respects; her speed was - / knots. however, the stokehold temperature had reached ° fahrenheit! she returned to her slip at : p.m. on december , , the committee in a written report to the secretary of the navy,[ ] gave a description of the vessel and praised her performance. at this time a set of plans was made by "mr. morgan," of whom no other reference has appeared, and sent to the navy department. these cannot now be found. the committee recommended the battery be commissioned and used for training purposes. this suggestion was not followed. the ship remained in her slip during the winter, and in june she was turned over to the navy and delivered to captain samuel evans, commandant of the new york navy yard. captain joseph bainbridge was assigned to her command. however, she was not commissioned and soon after her delivery she was housed over and placed "in ordinary," that is, laid up. the final settlement showed that the committee, as navy agents, had paid out $ , . with $ . unpaid, as well as a claim for $ , . by adam and noah brown, making a total of $ , . . the following year, on june , , she was unroofed and put into service with a small crew. with president james monroe on board, she left the navy yard about noon for a short trip to the narrows and then to staten island and returned in the evening. the next day she was again placed "in ordinary." four years later, in , when her guns and machinery were removed, it was found that she was rapidly becoming rotten. she was then utilized as a receiving ship. at : p.m. on june , , she blew up, killing men and woman, with persons listed as injured. among those killed was one officer, lt. s. m. brackenridge. two lieutenants and a sailing master were hurt, four midshipmen were severely injured, and five persons were listed as missing. the explosion of - / barrels of condemned gunpowder was sufficient, due to her rotten condition, to destroy the ship completely. a court of inquiry blamed a -year-old gunner, who supposedly entered a magazine with a candle to get powder for the evening gun. it was stated to the court that about pounds of powder in casks and in cartridges was on board the ship at the time.[ ] she was not replaced until the coast-defense steamer _fulton_ was built in - , though in the navy purchased for $ , a "steam galliot" of tons, the _sea gull_, to be used as a dispatch boat for the west indian squadron engaged in suppressing piracy during . in she was laid up at philadelphia, and in she was sold for $ , . it is a curious fact that the battery did not receive an official name, as did the sailing blockship on the ways at new orleans, which at the end of the war of was officially listed as the _tchifonta_. nor was the battery given a number, as were the gunboats. in official correspondence and lists, the steam battery is referred to as the "fulton steam frigate," or as the "steam battery," but in later years she was referred to as the "fulton" or "fulton the first." perhaps the explanation is that as she was the only one of her kind she was not numbered, and as she was not considered fit for coastal or extended ocean voyages, she was not given a name. surviving designs for floating batteries the designs of american blockships that have survived are those of the _tchifonta_,[ ] feet long, -foot moulded beam, -foot -inch depth in hold, and about feet inches on deck. she was to carry a battery of long guns ( -pdr.), on the main deck carronades ( -pdr.), on forecastle and quarter decks. she was to have been rigged to rather lofty and very square topgallant sails, and would have been capable of sailing fairly well, though of rather shoal draft, drawing only about feet inches when ready for service. she was sold on the stocks at the end of the war and her later history is not known. another and earlier design for a blockship, or floating battery, was prepared by christian bergh for captain charles stewart in . this was a sailing vessel for the defense of the port of new york, planned to mount guns ( -pdr.), on her two lower decks and carronades ( -pdr.), on her spar deck. she was to be feet inches between perpendiculars, a -foot moulded beam, -foot depth of hold, and drawing about feet when ready for service. she was intended to be ship-rigged, but was never built.[ ] a few small sloop-rigged block vessels also were built during jefferson's administration. the sloop-of-war _saratoga_, built on lake champlain by the browns, in , was practically a blockship. a plan for a proposed "guard ship," or "floating battery," was made by james marsh at charleston, south carolina, in . this was an unrigged battery, feet extreme length, -foot moulded beam, -foot depth of hold, to mount guns ( -pdr.), on a flush deck, with a covering deck above.[ ] [illustration: figure .--design for an unrigged floating battery proposed by james marsh, charleston, south carolina, march , .] through the courtesy of the trustees of the national maritime museum, greenwich, england, the rigsarkivet, copenhagen, denmark, and the statens sjöhistoriska museum, stockholm, sweden, the author has been able to illustrate in this article the designs of some of the early floating batteries. in the last quarter of the th century and later, the danes had built sail-propelled floating batteries or blockships, which were employed in the defense of copenhagen. the british built at least one sail-propelled battery, the _spanker_, in . this was a scow of very angular form with overhanging gun-deck, bomb-ketch-rigged, and about feet overall -foot inches moulded beam and -foot depth of hold. she is said to have been a failure due to her unseaworthy proportions and form; the overhanging gun deck and sides were objected to in particular. she is called a "stationary battery" in her plans, which are in the admiralty collection of draughts, national maritime museum, greenwich. controversial descriptions the contemporary descriptions of the fulton _steam battery_ do not agree. this was in part due to differences between the dimensions given out by fulton during the negotiations with the federal government, and after the ship's construction was authorized. from the context of various statements concerning the projected vessel, such as that of the naval officers, the changes in the intended dimensions of the ship can be seen. for example, the officers state the model and plan shown them would produce a battery carrying guns ( - and -pdrs.), and a letter from fulton to jones,[ ] shows she was to be feet on deck and -foot beam. the final reported dimensions, given by the supervisory committee,[ ] are feet length, feet beam, and feet depth. in addition there are a few foreign accounts which give dimensions and descriptions. the most complete was probably that of jean baptiste marestier, a french naval constructor who visited the united states soon after the end of the war of and published a report on american steamboats in .[ ] the _steam battery_ is barely mentioned though a drawing of one of her boilers is given. marestier made another report on the american navy, however. extensive searches have been made for this in paris over the last years, but this paper has not been found in any of the french archives. references to the original text indicate that the naval report dealt very extensively with the _steam battery_. some of his comments on the battery appeared in _procès-verbaux des séances de l'académie des sciences_.[ ] marestier considered the powers of the battery to have been overrated due to fanciful accounts of some laymen writers. he was aware of the shortcomings of the double hull in a steam vessel at the then-possible speeds, but he apparently thought two engines, one in each hull and each with its boilers would be better than fulton's arrangement of boilers in one hull and engine in the other. he noted that the paddle wheel turned - rpm and that steam pressure sustained a column of mercury to centimeters. the safety valve was set at centimeters. fuel consumption was - / cords of pine wood per hour. in view of the access marestier is known to have had to american naval constructors, shipbuilders, and engineers, it is highly probable that he not only obtained the building plan of the ship but also some of the earlier project plans from the builders and from fulton's superintendent, stoudinger. it is, therefore, a great misfortune that his lengthy report on the _battery_ cannot be produced. a french naval officer who investigated the ship, m. montgéry, also wrote a description, published in "notice sur la vie et les travaux de robert fulton."[ ] [illustration: figure .--floating battery _spanker_ built, in england by william barnard, at deptford on the thames, and launched june , . rigged as a bomb ketch, its length is feet inches in the keel, extreme beam feet inches, depth of hold feet. upper deck plan also shown.] it should be noted in regard to what montgéry wrote about the _battery_, that in it had been considered desirable to disarm the ship. the engineer in charge, william purcell, had reported that as there were not proper scuppers, dirt and water had entered the hull and had collected under the engine and boilers, causing damage to the hull, and also that with guns removed, the _battery_ would float too high for the paddle wheel to propel the vessel; so it had been decided to remove all machinery as well as the armament. montgéry's description, published in , was taken from his report to the minister of marine and colonies. it noted the battery was made of two hulls separated by a channel, or "race," - / feet wide, running the full length of the vessel. the two hulls were joined by a deck just above the waterline, as well as by an upper deck, and also connected at their keels by means of oak beams each foot square. the vessel was feet long, feet beam, and feet deep. sides were feet inches thick, and the ends of the hull were rounded and alike. there were two rudders at each end, one on each hull, alongside the race. the eight paddle blades, each - / feet by feet, turned in either direction by stopping the engine piston at half-stroke and reversing the flow of steam. rigged with two lateen sails and two jibs, the ship sailed either end first. the engine of hp was in one hull and two boilers were in the other. other sources, marestier, and colden in _procès-verbaux des séances de l'académie des sciences_,[ ] gave additional information (some of it incorrect): the engine was inclined, with a -foot-diameter cylinder, -foot stroke, direct-connected to the paddle wheel, which was turned at rpm. the boilers were × feet with the fireboxes in inside cylinders, each about feet in diameter, and extending about half the length of the boiler from the fire doors. two fire tubes, each about feet in diameter, returned the gases from the inside end of the fireboxes to the stacks at the firing end. except at the fire-door end, the firebox was completely surrounded by water. the boiler pressure of about psi was not maintained, varying somewhat with each stroke of the engine. water level in the boilers was indicated by try cocks. the safety valve was controlled by a counterbalanced lever. a jet of salt water was injected into the exhaust trunk to form a vacuum by condensation. an air pump transferred condensate and sea water into a tank from which it passed overboard. only about a tenth of this water was returned to the boilers. montgéry stated also that only the lower or gun deck was to be armed. no bulwarks were on the spar deck, only iron stanchions to which were fastened a breastwork of wet cotton bales when the _steam battery_ was in action. the _battery_ was designed to carry guns ( -pdr.), with guns in each end and on each side, but no guns in the wake of paddle wheel and machinery. hatches to give air to the stokehold were located amidships. the _battery_ was to have been supplemented at the ends of each hull by a columbiad "submarine gun" ( -pdr.), fulton's invention, but these were not fitted. provision was to be made in the fireboxes for heating shot, and a force pump with a cylinder inches in diameter was employed to throw a stream of cold water, about - gallons per minute, for a distance of about two hundred feet. this could be done only when the paddle wheel was not in operation. the paddle wheel was housed, the top fitted with stairs to the spar deck. the gun deck, over the race, was used in part for staterooms, of which the bulkheads were permanent. hammocks for the complement of men were to be slung on the rest of the gun deck. the ship drew feet inches, with the port sills about - / feet above the loadline. burning wood, the vessel could carry about days' supply of fuel; burning coal, she carried days' supply. montgéry said that the vessel would be vulnerable to bombshells and hot shot, and that furthermore she could be boarded. the displacement of the ship, at service draft, was , tons, a figure montgéry obtained from a copy of the original plan given him by noah brown. [illustration: figure .--french sketch, in rigsarkivet, copenhagen, of inboard profile and arrangement of fulton's _steam battery_, showing details of the fulton engine, probably taken from one of his preliminary designs.] in , lieutenant ralph r. gurley, usn, attempted a reconstruction in sketches of the vessel published in his article "the u.s.s. _fulton_ the first" in the _u.s. naval institute proceedings_.[ ] this reconstruction was based on the patent office drawing prepared for fulton, and published by stuart and bennett, and the foregoing french sources. the patent office drawing showed the engine was an inclined cylinder and lt. gurley shows this in his sketch; in his text (p. ) he says, "the engine was an inclined, single-cylinder affair with a -foot base and a -foot stroke." gurley's attempt to reconstruct the _steam battery_ is the only one known to the author. copenhagen plans in , kjeld rasmussen, naval architect of the danish greenland company, was requested by the author to inspect in the danish royal archives at copenhagen a folio of american ship plans, the index of which had listed some civil war river monitors. mr. rasmussen found the monitor plans had been withdrawn but discovered that three plans of fulton's _steam battery_ existed, as well as plans of the first _princeton_, a screw sloop-of-war. copies of the _steam battery's_ plans were obtained at copenhagen in september through the courtesy of the archivist, and were found to consist of the lines, copied in , an inboard profile and arrangement, and a sail and rigging plan. from these the reconstruction for a scale model was drawn and is presented here with reproductions of the original drawings upon which the reconstruction is based. it is apparent that montgéry's description is generally accurate. the vessel is a catamaran, made of two hulls, double-ended and exactly alike. the outboard sides are "moulded," with round bilges, the inboard sides are straight and flat, as though a hull had been split along the middle line and then planked up flat where split. the hulls are separated by the race, in which the paddle wheel is placed at mid-length. the topsides are made elliptical at the ends, and the midsection shows a marked tumble-home over the thick topside planking but less on the moulded lines. [illustration: figure .] the lines plan agreed rather closely to montgéry's description of the hull. after careful fairing it was found the lines drawing would produce a vessel feet inches overall outside the stems, or about feet over the planked rabbets, with a moulded beam of feet and extreme beam of feet. the moulded depth was feet inches and the width of the race was feet inches, plank to plank. the room and space of framing shown was feet. the designed draft appears to be feet and this would bring the port sills feet inches above the loadline and the underside of the gun-deck beams about feet inches above the loadline. the lines plan is a danish copy, probably of the building plan by noah brown, and may be based on the plan montgéry obtained from brown. the spar deck has the iron stanchions (gurley translated these as "chandeliers") which are set inboard feet from the plank-sheer. this gives room for cotton bales, outboard the stanchions, to form a barricade. as will be seen by comparing the original danish drawing with the model drawing, the construction indicates that the iron stanchions should be carried around the ends of the hull in the same manner as along the sides, since the lower ends of the iron stanchions pass through the spar deck and are secured to the inside of the inner ceiling of the gun deck. the rudders are as shown in the danish drawing, and it is supposed that they were operated ferryboat fashion, one at each end of the vessel. hence, each pair of rudders was toggled together by a cross-yoke. this was probably operated by a tiller (possibly the cross-yokes and tillers were of iron) pivoted under the beams of the gun deck close to the ends of the ship. tiller ropes led from a tackle under the gun-deck through trunks to the spar deck, where the wheels were placed. this allowed proper sweep to the tillers and operation of each pair of rudders. the paddle wheel was apparently of iron, with wooden blades, and agrees with montgéry's description. in the plan for the model it is shown raised inches above the original design position, to agree with trial requirements. [illustration: figure .--original lines of robert fulton's _steam battery_, a danish copy dated september , ; found in rigsarkivet, copenhagen.] it should be observed that the close cl-to-cl frame spacing created a hull having frames touching one another, at least to above the turn of the bilge, so the vessel was almost solid timber, before being planked and ceiled, from keel to about the loadline. the sides are not only heavily planked but, after the frames were ceiled with extraordinarily heavy, square timbering, a supplementary solid, vertical framing was introduced inboard and another ceiling added. the sides scale about feet from outside the plank to the inboard face of the inner ceiling at the level of the gunports. the hulls were tied together athwartship by the deck beams of the gun deck and spar deck, except in the wake of the paddle wheel. knees were placed along the sides of the race at alternate gun-deck beams. in addition, the -foot-square timbers, crossing the race at the rabbets of the hulls, (mentioned by montgéry) are shown. these must have created extraordinary resistance, even at the low speed of this steamer. the deck details shown are the results of reconstruction of the inboard works. history of double-hull craft the use of catamaran hulls, or "double-hulls," has been periodically popular with ship designers since the time of charles ii of england. the earliest of such vessels known in the present day were four sloops or shallops designed - by sir william petty, who was an inventor in the field of naval architecture and received some attention from charles ii and from the royal society. the first petty experiment, the _simon & jude_, later called _invention i_, was launched october , . she was designed with two hulls cylindrical in cross section, each feet in diameter, and feet long. a platform connected the hulls, giving the boat a beam of a little over feet. she had a -foot mast stepped on one of the crossbeams connecting the hulls, with a single gaff sail. in sailing trials she beat three fast boats: the king's barge, a large pleasure boat, and a man-of-war's boat. this "double-bottom," also called a "sluiceboat" or "cylinder," was later lengthened at the stern to make her feet overall. [illustration: figure .] the king did not support petty, to the latter's great disappointment, and petty next built a larger double-bottom, _invention ii_. this catamaran was lapstrake construction. not much is known of this boat except that she beat the regular irish packet boat, running between holyhead and dublin, in a race each way, winning a £ wager. she was launched in july ; what became of her was not recorded. a third and still larger boat, the _experiment_, launched december , , appears to have been a large sloop. this vessel sailed by way of the thames in april and went to oporto, portugal. she left portugal october , , for home, but apparently went down with all hands in a severe storm. [illustration: figure .--danish copy of original sail plan of robert fulton's _steam battery_, dated september , , in rigsarkivet, copenhagen.] [illustration: figure .--lines of fulton's _steam battery_, as reconstructed for a model in the museum of history and technology.] [illustration: figure .--a reconstruction of inboard works of the _steam battery_, for construction of the model in the museum of history and technology.] for years petty did no more with the type, but finally, in july , he laid down a still larger sloop with two decks and a mast standing feet above her upper deck. she was named _st. michael the archangel_ and is probably the design in pepys' _book of miscellaneous illustrations_ in magdalene college, cambridge, england. this vessel proved unmanageable and was a complete failure. [illustration: figure .--model lines redrawn to outside of plank to show hydrodynamic form of the _steam battery_.] though the double canoes of the pacific islands were probably known to some in europe in , there is no evidence that petty based his designs on such craft. he appears to have produced his designs spontaneously from independent observations and resulting theories. before petty concluded his experiments, a number of double-hull craft had been produced by others; however, some "double" craft, such as "double shallops" may have been "double-enders," as shown by a "double-moses boat" of the th century and later.[ ] the use of two canoes, joined by a platform or by poles was common in colonial times; in maryland and virginia, dugouts so joined were used to transport tobacco down the tidal creeks to vessels' loading. such craft were also used as ferries. m. v. brewington's _chesapeake bay log canoes_[ ] and paul wilstack's _potomac landings_[ ] illustrate canoes used in this manner. a catamaran galley, two round-bottom hulls, flat on the inboard side (a hull split along the centerline and the inboard faces planked up), feet long and each hull a -foot moulded beam, -foot inches moulded depth, and placed feet apart, was proposed by sir sidney smith, r.n., in the 's, and built by the british admiralty. named _taurus_, she is shown by the admiralty draught to have been a double-ender, with cabins amidships on the platform, an iron rudder at each end (between the hulls) steered with tillers (to unship), and with a ramp at one end. the plans are undated, signed by captain sir sidney smith, and a field-carriage gun is shown at the ramp end of the boat. this, and the heavy rocker in the keels, suggests the _taurus_ was intended for a landing boat. no sailing rig is indicated, but tholes for oars or sweeps on each side are shown. the oarsmen apparently sat on deck, or on low seats, with stretchers in hatches between each pair of tholes (admiralty collection of draughts, the national maritime museum, greenwich, england). [illustration: figure .--general plan of the _taurus_, a catamaran galley gunboat proposed by sir sidney smith, r.n., to the british admiralty in the early years of the french revolution. from the admiralty collection of draughts, national maritime museum, greenwich.] another experimenter with the double-hull type of vessel was a wealthy scot named patrick miller who was particularly interested in manual propulsion of vessels, employing geared capstans to operate paddle wheels. in a letter dated june , , miller offered gustav iii of sweden a design for a double-hulled -gun ship-of-the-line (rating as a -gun ship) propelled by manually operated capstans connected to a paddle wheel between the hulls. she was rigged to sail, with five masts and was to be feet long, feet beam, and feet draft; the hulls were feet apart. this project was submitted by the king to fredrik henrik af chapman, the great swedish naval architect, who made an adverse report. chapman pointed out in great detail that the weight of the armament, the necessary hull structure, the stores, crew, ammunition, spars, sails, rigging and gear, would greatly exceed miller's designed displacement. he also pointed out the prime fault of catamarans under sail--slow turning in stays. he suggested that the speed under sail would be disappointing. he doubted that a double-hull ship of such size could be built strong enough to stand a heavy sea. he remarked that english records showed that a small vessel of the catamaran type had been built between and which had sailed well (this may have been one of petty's boats), and that " years ago" he had seen miles from london, a similar boat that had been newly built by lord baltimore and was about feet long; this was a failure and was discarded after one trial. therefore, said chapman, the miller project was not new but rather an old idea. chapman's final remark is perhaps the best illustration of his opinion of the catamaran, "despite all this, two-hull vessels are completely sound when the theory can be properly applied; that is in vessels of very light weight, and of small size, with crews of one or two men." a "model" of such a double-hull ship--the _experiment_, built at leith, scotland, in by j. laurie--was sent to sweden by miller. she was feet long, feet beam, and cost £ . this vessel arrived in the summer of and king gustav in a letter dated july ordered col. michael anckerswärd to welcome the vessel at stockholm. the king presented miller with a gold snuffbox and a painting was made of the vessel. the _experiment_ had five paddle wheels in tandem between her hulls, operated by geared capstans on deck. these gave her a speed of knots but caused the crew to suffer from exhaustion in a short time. the vessel was badly strained in a storm and was finally abandoned at st. petersburg, russia.[ ] [illustration: figure .] miller later turned to the idea of employing steam instead of manual power and built a -foot double-hulled pleasure boat of iron fitted with a steam engine built by william symington. also named _experiment_, she was an apparent success, so miller had a -foot boat built of the double-hull design and fitted with an engine built by symington. she reached a speed of mph on the forth and clyde canal. however, miller lost interest when he found that the symington engine was unreliable and that great britain showed very little public support for such projects. fulton was acquainted with symington's work and probably had heard of miller's vessels. at any rate, he employed the double-hull principle in his steam ferryboats, the first of which was the _jersey_, a -ton vessel built by charles browne, which began service july , . the next year he had a sister ship built, the _york_. these vessels were based on his patent drawing of . in he had another vessel of this type built, the _nassau_. it was, therefore, logical that he should apply this design to the _steam battery_. the double-hull design had worked well in these ferries, and the design would give protection from shot to the paddle wheel. the _battery_ would have the ability to run forward or astern so as not to be exposed to a raking fire from the enemy while maneuvering in action. the application of this "ferryboat" principle to the _battery_ reduced the need for extreme maneuverability, the catamaran's weakest point, even at low speed. the resistance factors in the design are of relatively small importance, for the speed possible under steam in this period was very low. however, the plans show an apparently efficient hull form for the power available, aside from the drag of the beams across the race in the vicinity of the keel. the displacement was adequate. the height of the gun-deck above the water at the race made the _battery_ unsuitable for rough-water operation, but there is no evidence that fulton or the sponsors of the vessel considered the _battery_ as a coastwise or seagoing steamer. however, the clearance of the gun deck above the water and the dip of the paddle wheel would have made the additional weight of an upper- or spar-deck battery prohibitive even had experience in action proven it desirable. sail and inboard plans [illustration: figure .--lines of _taurus_. from the admiralty collection of draughts, national maritime museum, greenwich.] the sail and rigging plan is likewise a danish copy and shows the two-masted lateen rig employed. the hull is shown with bulwarks and gunports on the spar deck but no other evidence that the _battery_ was finished in this manner has been found. the rig resembles that of some of josiah fox's designs for jeffersonian gunboats--double-enders designed to sail in either direction but without the jibs. the topmasts do not appear to be more than signal poles and apparently were not fitted with sails; however, some european lateeners did have triangular topsails over a lateen and it is possible the _battery_ may have carried such sails. considering the stability and displacement of the _battery_, the rig is very small and not sufficiently effective. shrouds were not required; the masts were supported by runners that were shifted when the yards were reversed, and in tacking. apparently the jibstays also could be slacked off so that the lateen yards would not have to be dipped under them. [illustration: figure .--rudder detail of _taurus_. from the admiralty collection of draughts, national maritime museum, greenwich.] the inboard profile is on tracing paper and the notes are in french. this drawing is of a simplified hull form having flat-bottom hulls with chines. it is possible that this is a tracing of a preliminary drawing obtained by marestier or montgéry, but no documentation can be found. its importance is that it shows in some detail the engine and boilers, as well as the wheelbox, and another drawing of the paddle wheel, more or less duplicating the wheel shown in the danish plan. no details of the deck arrangements are shown in any of the plans, except for the dome skylight over the fireroom in the boiler hull. both the lines plan and the inboard drawing show construction midsections and hull connections. these plans show that the engine was not inclined, but rather was vertical, contrary to fulton's patent drawing. the piston rod and the crosshead obviously passed through its gun deck in a large hatch. also it is plain that there must have been large hatches afore and abaft the wheelbox to make the stepped wheelbox construction desirable. there also must have been a hatch in the gun deck under the domed skylight. it is improbable that the engine and skylight hatches were used for ladderways, passing scuttles, or companionways. the boilers are shown in the inboard profile about as described and drawn by marestier but with two stacks on each boiler, one to each flue; marestier's sketch in his report on american steamships shows the flues of each boiler trunked into a single stack. the battery had two boilers and the stacks are at the boilers' fire-door end. the steam lines came off the crown of the boilers and probably passed through the ends of the wheelbox to the engine; a trunk for the steam lines would undoubtedly have been necessary. [illustration: figure .--sketch of -gun ship proposed by patrick miller to king gustav iii of sweden in . in statens sjöhistoriska museum, stockholm.] [illustration: figure .--patrick miller's manually propelled (paddle-wheel) catamaran ship _experiment_, built at leith, scotland, . scale drawing in statens sjöhistoriska museum, stockholm.] the engine is shown to have had counterbalanced side levers, one on each side, and a single flywheel on the outboard side. the cylinder is over the condenser or "cistern," connected by the steam line and valve box on the side. the cylinder crosshead is shown in the inboard profile to have reached the underside of the beams of the upper deck. the crosshead was connected by two connecting rods to the side levers. these levers operated the paddle wheel by connecting rods to cranks on the paddle-wheel shaft. there is another pair of connecting rods from the side levers to the crosshead of the air pump. all connecting rods are on one arm of the side levers, the other end having only a counterbalance weight beyond the fulcrum bearing. the flywheel has a shaft fitted with two gears, and is driven through idler gears from gears on the paddle-wheel shaft; it turns at about twice the speed of the paddle wheel. no other pumps or fittings are shown in the engine hull, although manual pumps were probably fitted to fill and empty the boilers. piping is not shown. [illustration: figure .--painting of the _experiment_ in the statens sjöhistoriska museum, stockholm.] the four rudders, toggled in pairs, are shown in both the lines and inboard drawings, but the shape is different in the two plans. operation must have been by a tiller under the gun-deck beams. the outer end of the tiller may have been pivoted on the toggle bar and the inboard end fitted, as previously described, with steering cable or chain tackles. this seems to be the only practical interpretation of the evidence. reconstructing the plans in the model it was necessary to reconstruct the deck arrangements without enough contemporary description. the outboard appearance and hull form, rig, and arrangement of armament require no reconstruction, for all that is of importance is shown in the lines and rig drawings, or in the inboard profile. the masts are shown to have been stepped over the race on the gun deck. the iron stanchions are shown in the lines drawing and in the construction section. however, their position at the ends of the _battery_ are apparently incorrectly shown in the original lines plan. the construction section shows these stanchions to have been stepped on the inside face of the inner ceiling and, as the ceiling structure was carried completely around the ship, the stanchions in the ends must have been placed inboard, as along the sides. the bowsprit was above deck and would probably be secured in the knighthead timbers at the ends of the hull, as well as by the heel bitts shown in the danish lines drawing. with the riding bitts shown inboard of the heel bitts at each end of the vessel, it is obvious that she would work her ground tackle at both ends and would therefore require two capstans; the wheelbox would prevent effective use of a single one. the capstans might be doubleheaded, as in some large frigates and ships-of-the-line. [illustration: figure .--sail plan of fulton's _steam battery_ as reconstructed for model in the museum of history and technology.] as to the remaining deck fixtures, hatches and fittings, these must be entirely a matter of speculation. ladderways, passing scuttles, hatches, trunks, galley, heads and cabins were obviously required in a fighting ship and can only be located on the theory that, when completed, the _battery_ was a practical vessel. it has been stated that the officers' cabins were over the race; the logical place for the heads, galley, wardroom and mess also would be over the race, giving the remaining part of the gun deck for the necessary hatches, ladderways, trunks, etc., in the two hulls, space required for armament, and to sling the hammocks of a watch below. as the vessel was never fully manned, apparently, the space for hammocks is not a serious problem in a reconstruction. if the vessel had been manned as proposed by men, hammocks for over would have been required, which would give very crowded quarters in view of the limited space available. though no specific requirements were stated in the reports of the trials, it seems reasonable to suppose that additional hatches were cut in the decks to improve the fireroom ventilation. in the reconstruction drawings, these hatchways as well as the other deck openings and deck fittings--such as bilge pumps, companionways, skylights, binnacles, wheels and wheel-rope trunks, cable trunks, steampipe casings, and stack fiddleys--have been located in an effort to meet the imagined requirements of the working of a ship of this unusual form. [illustration: figure .--model of _steam battery_ in the museum of history and technology. (smithsonian photo -e.)] [illustration: figure .--lines of steamer _congo_, built in - for the british admiralty and converted to a sailing survey vessel. from admiralty collection of draughts, national maritime museum, greenwich.] there are some unanswered questions that arose in the preparation of the reconstruction drawings. as has been shown, the original inboard arrangement plan found in copenhagen shows four smokestacks, while marestier's sketch of the vessel's boilers shows trunked flues indicating that two stacks were used. it is possible that the boilers were first fitted so that four stacks were required; alterations made as a result of steaming trials may well have included the introduction of trunked flues and the final use of two stacks in line fore-and-aft. this would have required a rearrangement of the fiddley hatches amidships. another troublesome question was the doubtful arrangement of the four companionways on the spar deck. perhaps only two were fitted, one on each side of the officers' staterooms while the ladderways at the crew's end of the ship were simple ladder hatches. the decision to use four bilge pumps is based upon the lack of drag in the keel of the hulls, which would prevent accumulation of bilge water at one end of the hull. the use of four single-barrel pumps instead of four double-barrel pumps may be questioned, for chain pumps requiring two barrels would have been practical. allowance for stores was made by use of platforms in the hold. it is known from statements made to the court of inquiry, that the magazines were amidships and that a part of these was close to the boilers. fuel and water would be in the lower hold under the platforms; hatches and ladderways are arranged to permit fueling the ship. a few prints or drawings of the ship, aside from the patent drawing, have been found. there are two prints that show the launch of the vessel. one, a print of , is in possession of the mariners' museum, newport news, va., and is reproduced in alexander crosby brown's _twin ships, notes on the chronological history of the use of multiple hulled vessels_.[ ] a poor copy of this print appears on page of bennett's _steam navy of the united states_, and another and inaccurate sketch is shown on page . these pictures were of no use in the reconstruction as they show no details that are not in the copenhagen plans. the patent drawing does not show deck details and in fact does not represent the vessel as built in any respect other than in being a catamaran with paddle wheel amidships between the hulls. the _steam battery_ did not have any particular influence on the design of men-of-war that followed her. in the first place, steampower was not viewed with favor by naval officers generally. this was without doubt due to prejudice, but engines in - were still unreliable when required to run for long periods, as experienced by the early ocean-going steamers. the great weight of the early steam engines and their size in relation to power were important, and also important were practical objections that prevented the design of efficient naval ocean steamers until about ; even then, the paddle wheels made them very vulnerable in action. until the introduction of the screw propellor it was not possible to design a really effective ocean-going naval steamer; hence until about - , sail remained predominant in naval vessels for ocean service, and steamers were accepted only in coast defense and towing services, or as dispatch vessels. no immediate use of the double hull in naval vessels of the maritime powers resulted from the construction of the _steam battery_. the flat-bottom chine-built design employed by fulton in _north river_, _raritan_, and other early steamboats was utilized in the design for a projected steamer by the british admiralty in - . this vessel was about feet overall, -foot beam, and -foot inches depth in hold. her design was for a flat-bottom, chine-built hull with no fore-and-aft camber in the bottom, a sharp entrance, and a square-tuck stern with slight overhang above the cross-seam. her side frames were straight and vertical amidships, but curved as the bow and stern were approached. she was to be a side-paddle-wheel steamer, and her hull was diagonally braced; the wheel and engine were to be about amidships where she was dead flat for about feet. however, the engine and boilers were not installed; the engine was utilized ashore for pumping, and the vessel was completed in the deptford yard as a sailing ship. under the name _congo_ she was employed in the african coast survey. her plan is in the admiralty collection of draughts, at the national maritime museum, greenwich, england. the double hull continued to be employed in both steam and team ferryboats in the united states and in england and france. a few river and lake steamers were also built with this design of hull. continued efforts to obtain fast sailing by use of the double hull produced a number of sailing catamarans; of these the herreshoff catamarans of the 's showed high speed when reaching in a fresh breeze. designs for double-hulled steamers appeared during the last half of the th century; in the _castalia_, a large, double-hull, iron, cross-channel steamer, was built by the thames iron-works company at blackwall, england. she was feet long, and each hull had a beam of feet. the paddle wheel was placed between the hulls and, ready for sea, she drew - / feet. she ran the miles between dover and calais in hour and minutes, a speed much slower than that of the paddle-wheel, cross-channel steamers having one hull. another double-hull steamer was built for this service by hawthorn, leslie and company, newcastle-on-tyne, scotland, in . first named _express_, she was renamed _calais-douvres_ when she went into service in may . her length was feet, her extreme beam feet, and each hull had a beam of feet, inches. she drew -foot - / inches ready for sea and the paddle wheel was between the hulls. on her trials she made knots and burned coal excessively. sold to france in , she was taken out of service in . though popular, she was not faster than the single-hull steamers in this service and had been a comparatively expensive vessel to build and operate. the many attempts to produce a very fast double-hull steamer and large sailing vessels have led to disappointment for their designers and sponsors. in the history of naval architecture, since petty's time, there have been a number of periods when the new-old idea of the double hull has become popular. craft of this type have been commonly well publicized but, on the whole, their basic designs have followed the same principles over and over again and have not produced the sought-for increase in speed and handiness. in very recent years there has been a revival in interest in sailing double-hull boats that is enthusiastic as to very small craft and somewhat restrained as to large boats. a few projects are under development for double-hull craft, power and sail, of over -foot length, including an oceanographic research vessel. in general, however, the performance of double-hull boats has shown that chapman's estimate of the type was reasonably correct and that there are limitations, particularly in maneuverability in the double-hull craft that could have been found by reference to the history of past experiments with the type. naval steamers. the demologos; or, fulton the first. at the close of the year eighteen hundred and thirteen, robert fulton exhibited to the president of the united states, the original drawing from which the engraving on plate one is sketched, being a representation of the proposed war-steamer or floating-battery, named by him, the demologos. this sketch possesses more than ordinary interest, from the circumstance that it is, doubtless, the only record of the _first war-steamer in the world_, designed and drawn by the immortal fulton, and represented by him to the executive, as capable of carrying a strong battery, with furnaces for red hot shot, and being propelled by the power of steam, at the rate of _four_ miles an hour. it was contemplated that this vessel, besides carrying her proposed armament on deck, should also be furnished with submarine guns, two suspended from each bow, so as to discharge a hundred pound ball into an enemy's ship at ten or twelve feet below her water-line. in addition to this, her machinery was calculated for the addition of an engine which would discharge an immense column of water upon the decks, and through the port-holes of an enemy, making her the most formidable engine for warfare that human ingenuity has contrived. the estimated cost of the vessel was three hundred and twenty thousand dollars, nearly the sum requisite for a frigate of the first class. the project was zealously embraced by the executive, and the national legislature in march, eighteen hundred and fourteen, passed a law, authorizing the president of the united states to cause to be built, equipped, and employed, one or more floating batteries, for the defense of the waters of the united states. the building of the vessel was committed by the coast and harbor defense association, to a sub-committee of five gentlemen, who were recognized by the government as their agents for that purpose, and whose interesting history of the steam frigate is copied in note a, of the appendix to this volume. robert fulton, whose soul animated the enterprise, was appointed the engineer; and on the twentieth day of june, eighteen hundred and fourteen, the keel of this novel steamer was laid at the ship-yard of adam and noah brown, her able and active constructors, in the city of new york, and on the twenty-ninth of the following october, or in little more than four months, she was safely launched, in the presence of multitudes of spectators who thronged the surrounding shores, and were seen upon the hills which limited the beautiful prospect around the bay of new york. the river and bay were filled with steamers and vessels of war, in compliment to the occasion. in the midst of these was the enormous floating mass, whose bulk and unwieldy form seemed to render her as unfit for motion, as the land batteries which were saluting her. in a communication from captain david porter, u. s. navy, to the hon. secretary of the navy, dated new york, october , , he states,--"i have the pleasure to inform you that the "fulton the first," was this morning safely launched. no one has yet ventured to suggest any improvement that could be made in the vessel, and to use the words of the projector, '_i would not alter her if it were in my power to do so._' "she promises fair to meet our most sanguine expectations, and i do not despair in being able to navigate in her from one extreme of our coast to the other. her buoyancy astonishes every one, she now draws _only eight feet three inches water_, and her draft will only be _ten_ feet with all her guns, machinery, stores, and crew, on board. the ease with which she can now be towed with a single steamboat, renders it certain that her velocity will be sufficiently great to answer every purpose, and the manner it is intended to secure her machinery from the gunner's shot, leaves no apprehension for its safety. i shall use every exertion to prepare her for immediate service; her guns will soon be mounted, and i am assured by mr. fulton, that her machinery will be in operation in about six weeks." on the twenty-first of november, the steam frigate was moved from the wharf of messrs. browns, in the east river, to the works of robert fulton, on the north river, to receive her machinery, which operation was performed by fastening the steamboat "car of neptune," to her larboard, and the steamboat "fulton," to her starboard side; they towed her through the water from three and a-half to four miles per hour. the dimensions of the "fulton the first" were:-- length, one hundred and fifty-six feet. breadth, fifty-six feet. depth, twenty feet. water-wheel, sixteen feet diameter. length of bucket, fourteen feet. dip, four feet. engine, forty-eight inch cylinder, and five feet stroke. boiler, length, twenty-two feet; breath, twelve feet; and depth, eight feet. tonnage, two thousand four hundred and seventy-five. by june, eighteen hundred and fifteen, her engine was put on board, and she was so far completed as to afford an opportunity of trying her machinery. on the first of june, at ten o'clock in the morning, the "fulton the first," propelled by her own steam and machinery, left the wharf near the brooklyn ferry, and proceeded majestically into the river; though a stiff breeze from the south blew directly ahead, she stemmed the current with perfect ease, as the tide was a strong ebb. she sailed by the forts and saluted them with her thirty-two pound guns. her speed was equal to the most sanguine expectations; she exhibited a novel and sublime spectacle to an admiring people. the intention of the commissioners being solely to try her enginery, no use was made of her sails. after navigating the bay, and receiving a visit from the officers of the french ship of war lying at her anchors, the steam frigate came to at powles' hook ferry, about two o'clock in the afternoon, without having experienced a single unpleasant occurrence. on the fourth of july, of the same year, she made a passage to the ocean and back, and went the distance, which, in going and returning, is fifty-three miles, in eight hours and twenty minutes, without the aid of sails; the wind and tide were partly in her favor and partly against her, the balance rather in her favor. in september, she made another trial trip to the ocean, and having at this time the weight of her whole armament on board, she went at an average of five and a half miles an hour, with and against the tide. when stemming the tide, which ran at the rate of three miles an hour, she advanced at the rate of two and a-half miles an hour. this performance was not more than equal to robert fulton's expectations, but it exceeded what he had premised to the government, which was that she should be propelled by steam at the rate of from three to four miles an hour. the english were not uninformed as to the preparations which were making for them, nor inattentive to their progress. it is certain that the steam frigate lost none of her terrors in the reports or imaginations of the enemy. in a treatise on steam vessels, published in scotland at that time, the author states that he has taken great care to procure _full_ and _accurate_ information of the steam frigate launched in new york, and which he describes in the following words:-- "length on deck, _three hundred feet_; breadth, _two hundred feet_; thickness of her sides, _thirteen feet_ of alternate oak plank and cork wood--carries forty-four guns, four of which are _hundred pounders_; quarter-deck and forecastle guns, forty-four pounders; and further to annoy an enemy attempting to board, can discharge _one hundred gallons of boiling water in a minute_, and by mechanism, brandishes _three hundred cutlasses_ with the utmost regularity over her gunwales; works also an equal number of heavy iron pikes of great length, darting them from her sides with prodigious force, and withdrawing them every quarter of a minute"!! the war having terminated before the "_fulton the first_" was entirely completed, she was taken to the navy yard, brooklyn, and moored on the flats abreast of that station, where she remained, and was used as a receiving-ship until the fourth of june, eighteen hundred and twenty-nine, when she was blown up. the following letters from commodore isaac chauncey (then commandant of the new york navy yard) to the honorable secretary of the navy, informing him of the distressing event, concludes this brief history of the _first steam vessel of war ever built_. * * * * * u. s. navy yard, new york, _june th, _. sir: it becomes my painful duty to report to you a most unfortunate occurrence which took place yesterday, at about half past two o'clock, p. m., in the accidental blowing up of the receiving ship fulton, which killed twenty-four men and a woman, and wounded nineteen; there are also five missing. amongst the killed i am sorry to number lieutenant s. m. brackenridge, a very fine, promising officer, and amongst the wounded are, lieutenants charles f. platt, and a. m. mull, and sailing-master clough, the former dangerously, and the two last severely; there are also four midshipmen severely wounded. how this unfortunate accident occurred i am not yet able to inform you, nor have i time to state more particularly; i will, as soon as possible, give a detailed account of the affair. i have the honor to be, sir, very respectfully, j. chauncey. hon. john branch, _secretary of the navy, washington._ u.s. navy yard, new york, _june th, _. sir: i had been on board the "fulton" all the morning, inspecting the ship and men, particularly the sick and invalids, which had increased considerably from other ships, and whom i had intended to ask the department permission to discharge, as being of little use to the service. i had left the ship but a few moments before the explosion took place, and was in my office at the time. the report did not appear to me louder than a thirty-two pounder, although the destruction of the ship was complete and entire, owing to her very decayed state, for there was not on board, at the time, more than two and a-half barrels of damaged powder, which was kept in the magazine for the purpose of firing the morning and evening gun. it appears to me that the explosion could not have taken place from accident, as the magazine was as well, or better secured, than the magazines of most of our ships, yet it would be difficult to assign a motive to those in the magazine for so horrible an act, as voluntarily to destroy themselves and those on board. if the explosion was not the effect of design, i am at a loss to account for the catastrophe. i have the honor to be, sir, very respectfully, j. chauncey. hon. john branch, _secretary of the navy, washington_. appendix. note a. steam frigate. _report of henry rutgers, samuel l. mitchel, and thomas morris, the commissioners superintending the construction of a steam vessel of war, to the secretary of the navy._ new york, _december th, _. sir: the war which was terminated by the treaty of ghent, afforded, during its short continuance, a glorious display of the valor of the united states by land and by sea--it made them much better known to foreign nations, and, what is of much greater importance, it contributed to make them better acquainted with themselves--it excited new enterprises--it educed latent talents--it stimulated to exertions unknown to our people before. a long extent of coast was exposed to an enemy, powerful above every other on the ocean. his commanders threatened to lay waste our country with fire and sword, and, actually, in various instances, carried their menaces into execution. it became necessary, for our defense, to resist, by every practicable method, such a formidable foe. it was conceived, by a most ingenious and enterprising citizen, that the power of steam could be employed to propel a floating battery, carrying heavy guns, to the destruction of any hostile force that should hover on the shores, or enter the ports of our atlantic frontier. the perfect and admirable success of his project for moving boats containing travelers and baggage by the same elastic agent, opened the way to its employment for carrying warriors and the apparatus for fighting. the plan was submitted to the consideration of the executive of an enlightened government. congress, influenced by the most liberal and patriotic spirit, appropriated money for the experiment, and the navy department, then conducted by the honorable william jones, appointed commissioners to superintend the construction of a convenient vessel under the direction of robert fulton, the inventor, as engineer, and messrs. adam and noah brown, as naval constructors. the enterprise, from its commencement, and during a considerable part of its preparatory operations, was aided by the zealous co-operation of major general dearborn, then holding his head-quarters at the city of new york, as the officer commanding the third military district. the loss of his valuable counsel in conducting a work which he had maturely considered, and which he strongly recommended, was the consequence of his removal to another section of the union, where his professional talents were specially required. the keels of this steam-frigate were laid on the twentieth day of june, eighteen hundred and fourteen. the strictest blockade the enemy could enforce interrupted the coasting trade, and greatly enhanced the price of timber. the vigilance with which he guarded our coast against intercourse with foreign nations, rendered difficult the importation of copper and iron. the same impediment attended the supplies of coal heretofore brought to new york from richmond and liverpool. lead, in like manner, was procured under additional disadvantages. these attempts of the enemy to frustrate the design, were vain and impotent. all the obstacles were surmounted. scarcity of the necessary woods and metals were overcome by strenuous exertions; and all the blockading squadron could achieve, was not a disappointment in the undertaking, but merely an increase of the expense. so, in respect to tradesmen and laborers, there was an extraordinary difficulty. shipwrights had repaired to the lakes, for repelling the enemy, in such numbers, that, comparatively speaking, few were left on the seaboard. a large portion of the men who had been engaged in daily work, had enlisted as soldiers, and had marched under the banners of the nation to the defense of its rights--yet amidst the scarcity of hands, a sufficient number were procured for the purpose which the commissioners had in charge. an increase of wages was the chief impediment, and this they were enabled practically to overcome. by the exemplary combination of diligence and skill, on the part of the engineer and constructors, the business was so accelerated, that the vessel was launched on the twenty-ninth day of october, amidst the plaudits of an unusual number of citizens. measures were immediately taken to complete her equipment; the boiler, the engine, and the machinery were put on board with all possible expedition. their weight and size far surpassed any thing that had been witnessed before among us. the stores of artillery in new york not furnishing the number and kind of cannon which she was destined to carry, it became necessary to transport guns from philadelphia. a prize, taken from the enemy, put some fit and excellent pieces at the disposal of the navy department. to avoid the danger of capture by the enemy's cruisers, these were carted over the miry roads of new jersey. twenty heavy cannon were thus conveyed by the strength of horses. carriages of the most approved model were constructed, and every thing done to bring her into prompt action, as an efficient instrument of war. about this time, an officer, pre-eminent for bravery and discipline, was commissioned by the government to her command. prior to this event, it had been intended by the commissioners to finish her conformably to the plan originally submitted to the executive. she is a structure resting upon two boats and keels, separated from end to end by a canal fifteen feet wide, and sixty-six long. one boat contained the caldrons of copper to prepare her steam. the vast cylinder of iron, with its piston, levers, and wheels, occupied a part of its fellow; the great water-wheel revolved in the space between them; the main or gun-deck supported her armament, and was protected by a bulwark four feet ten inches thick, of solid timber. this was pierced by thirty port-holes, to enable as many thirty-two pounders to fire red hot balls; her upper or spar deck was plain, and she was to be propelled by her enginery alone. it was the opinion of captain porter and mr. fulton, that the upper deck ought to be surrounded with a bulwark and stanchions--that two stout masts should be erected to support latteen sails--that there should be bowsprits for jibs, and that she should be rigged in a corresponding style. under authorities so great, and with the expectation of being able to raise the blockade of new london, by destroying, taking, or routing the enemy's ships, all these additions were adopted and incorporated with the vessel. it must here be observed, that during the exhaustion of the treasury, and the temporary depression of public credit, the commissioners were exceedingly embarrassed--their payments were made in treasury notes, which they were positively instructed to negotiate at par. on several occasions even these were so long withheld, that the persons who had advanced materials and labor were importunate for payment, and silently discontented. to a certain extent, the commissioners pledged their private credit. notwithstanding all this, the men, at one time, actually broke off. the work was retarded, and her completion unavoidably deferred, to the great disappointment of the commissioners, until winter rendered it impossible for her to act. under all this pressure, they, nevertheless, persevered in the important object confided to them. but their exertions were further retarded by the premature and unexpected death of the engineer. the world was deprived of his invaluable labors before he had completed this favorite undertaking. they will not inquire, wherefore, in the dispensations of divine providence, he was not permitted to realize his grand conception. _his discoveries, however, survive for the benefit of mankind_, and will extend to unborn generations. at length all matters were ready for a trial of the machinery to urge such a bulky vessel through the water. this essay was made on the first day of june, eighteen hundred and fifteen. she proved herself capable of opposing the wind, and of stemming the tide, of crossing currents, and of being steered among vessels riding at anchor, though the weather was boisterous and the water rough. her performance demonstrated that the project was successful--no doubt remained that a floating battery, composed of heavy artillery, could be moved by steam. the commissioners returned from the exercise of the day, satisfied that the vessel would answer the intended purpose, and consoled themselves that their care had been bestowed upon a worthy object. but it was discovered, that various alterations were necessary. guided by the light of experience, they caused some errors to be corrected, and some defects to be supplied. she was prepared for a second voyage with all practicable speed. on the fourth of july she was again put in action. she performed a trip to the ocean, eastward of sandy hook, and back again, a distance of fifty-three miles, in eight hours and twenty minutes. a part of this time she had the tide against her, and had no assistance whatever from sails. of the gentlemen who formed the company invited to witness the experiment, not one entertained a doubt of her fitness for the intended purpose. additional expedients were, notwithstanding, necessary to be sought for quickening and directing her motion. these were devised and executed with all possible care. suitable arrangements having been made, a third trial of her powers was attempted on the eleventh day of september, with the weight of twenty-six of her long and ponderous guns, and a considerable quantity of ammunition and stores on board; her draft of water was short of eleven feet. she changed her course by inverting the motion of the wheel, without the necessity of putting about. she fired salutes as she passed the forts, and she overcame the resistance of the wind and tide in her progress down the bay. she performed beautiful man[oe]uvres around the united states' frigate java, then at anchor near the light-house. she moved with remarkable celerity, and she was perfectly obedient to her double helm. it was observed that the explosion of powder produced very little concussion. the machinery was not affected by it in the smallest degree. her progress, during the firing, was steady and uninterrupted. on the most accurate calculations, derived from heaving the log, her average velocity was five and a-half miles per hour. notwithstanding the resistance of currents, she was found to make headway at the rate of two miles an hour against the ebb of the east river, running three and a-half knots. the day's exercise was satisfactory to the respectable company who attended, beyond their utmost expectations. it was universally agreed that we now possessed a new auxiliary against every maratime invader. the city of new york, exposed as it is, was considered as having the means of rendering itself invulnerable. the delaware, chesapeake, long island sound, and every other bay and harbor in the nation, may be protected by the same tremendous power. among the inconveniences observable during the experiment, was the heat endured by the men who attended the fires. to enable a correct judgment to be formed on this point, one of the commissioners (dr. mitchel) descended and examined, by a thermometer, the temperature of the hold, between the two boilers. the quicksilver, exposed to the radiant heat of the burning fuel, rose to one hundred and sixteen degrees of fahrenheit's scale. though exposed thus to its intensity, he experienced no indisposition afterwards. the analogy of potteries, forges, glass-houses, kitchens, and other places, where laborers are habitually exposed to high heats, is familiar to persons of business and of reflection. in all such occupations, the men, by proper relays, perform their services perfectly well. the government, however, will understand that the hold of the present vessel could be rendered cooler by other apertures for the admission of air, and that on building another steam frigate, the comfort of the firemen might be provided for, as in the ordinary steamboats. the commissioners congratulate the government and the nation on the event of this noble project. honorable alike, to its author and its patrons, it constitutes an era in warfare and the arts. the arrival of peace, indeed, has disappointed the expectations of conducting her to battle. that last and conclusive act of showing her superiority in combat, has not been in the power of the commissioners to make. if a continuance of tranquillity should be our lot, and this steam vessel of war be not required for the public defense, the nation may rejoice that the fact we have ascertained is of incalculably greater value than the expenditure--and that if the present structure should perish, we have the information never to perish, how, on a future emergency, others may be built. the requisite variations will be dictated by circumstances. owing to the cessation of hostilities, it has been deemed inexpedient to finish and equip her as for immediate and active employ. in a few weeks every thing that is incomplete could receive the proper adjustment. after so much has been done, and with such encouraging results, it becomes the commissioners to recommend that the steam frigate be officered and manned for discipline and practice. a discreet commander, with a selected crew, could acquire experience in the mode of navigating this peculiar vessel. the supplies of fuel, the tending of the fire, the replenishing of the expended water, the management of the mechanism, the heating of shot, the exercise of the guns, and various matters, can only become familiar by use. it is highly important that a portion of seamen and marines should be versed in the order and economy of the steam frigate. they will augment, diffuse, and perpetuate knowledge. when, in process of time, another war shall call for more structures of this kind, men, regularly trained to her tactics, may be dispatched to the several stations where they may be wanted. if, on any such disposition, the government should desire a good and faithful agent, the commissioners recommend captain obed smith to notice, as a person who has ably performed the duties of inspector from the beginning to the end of the concern. annexed to the report, you will find, sir, several statements explanatory of the subject. a separate report of our colleague, the honorable oliver wolcott, whose removal from new york precluded him from attending to the latter part of the business, with his accustomed zeal and fidelity, is herewith presented. a drawing of her form and appearance, by mr. morgan, as being like to give satisfaction to the department, is also subjoined, as are likewise an inventory of her furniture and effects, and an account of the timber and metals consolidated in her fabric. it is hoped these communications will evince the pains taken by the commissioners, to execute the honorable and responsible trust reposed in them by the government. samuel l. mitchel. thomas morris. henry rutgers. * * * * * u.s. government printing office: for sale by the superintendent of documents, u.s. government printing office washington, d.c. --price cents footnotes: [ ] _the american neptune_ ( ), vol. , pp. - . [ ] _the american neptune_ ( ), vol. , pp. - . [ ] new york, , pp. - . [ ] pittsburgh, , pp. - . [ ] see pages through for this report, which is reproduced from charles b. stuart, _naval and mail steamers of the united states_ (new york, ), app., pp. - . [ ] national archives, navy records plans, - - ; and howard i. chapelle, _history of the american sailing navy_ (new york: w. w. norton & co., ), pp. - . [ ] national archives, navy records plans, - - ; and chapelle, _history of the american sailing navy_, pp. , . [ ] national archives, navy records plans, - - . [ ] national archives, naval records collection, miscellaneous letters, , ii. [ ] see p. , reproduced from charles b. stuart, _naval and mail steamers of the united states_ (new york, ), p. . [ ] jean baptiste marestier, _mémoire sur les bateaux à vapeur des États-unis d'amérique, avec un appendice sur diverses machines relatives à la marine_ (paris: l'imprimerie royal, ). [ ] - , vol. , p. . [ ] _annales de l'industrie nationale et étrangère, ou mercure technologique_ (paris, ), pp. - . [ ] january , , vol. , pp. - . [ ] january-march , vol. , pp. - . [ ] howard i. chapelle, _american small sailing craft_ (new york: w. w. norton & co., inc., ), pp. , . [ ] newport news, va.: the mariners' museum, , p. . [ ] indianapolis, ind.: bobbs merrill, , p. . [ ] henry william edward, _the double bottom or twin hulled ship of sir william petty_ (oxford: the roxburghe club, ). [ ] publication no. (newport news: the mariners' museum, ), p. . index anckerswärd, col. michael, astor, john jacob, baltimore, lord. _see_ calvert. bennett, frank m., , , bergh, christian, biddle, james, brackenridge, s. m., brewington, m. v., brown, adam and noah, , , brown, alexander crosby, brown, noah, , , browne, charles, browns' yard, , calvert, george, lord baltimore, canning, stratford, chapman, fredrik henrik af, , charles ii of england, , coast and harbor defense company, coast defense society, , colden, c. d., danish greenland company, danish royal archives, , dearborn, henry, , decatur, stephen, deptford yard (england), eckford, henry, emmet, ----, evans, samuel, , fox, josiah, fulton, robert, , , , , , , , , , gurley, ralph r. (usn), , gustav iii of sweden, , hawthorn, leslie, and company (scotland), jefferson, thomas, jones, jacob, jones, william, laurie, j., lewis, jacob, lewis, morgan, marestier, jean baptiste, , , , mariners' museum, marsh, james, may, arthur j., miller, patrick, , mitchill, samuel l., , monroe, james, montgéry, m., , , morgan, "mr.", morris, thomas, , national maritime museum (england), , , pepys, samuel, perry, oliver, petty, sir william, , , , porter, david, purcell, william, rasmussen, kjeld, rigsarkivet (denmark), royal society of london, rutgers, henry, , smith, ---- (captain, usn), smith, sir sidney (rn), statens sjöhistoriska museum (sweden), stewart, charles, stiles, george, stoudinger, charles, stuart, charles b., , symington, william, thames iron-works company (england), tyler, david b., warrington, samuel, wilstack, paul, wolcott, oliver, , youle, john, foundry, little masterpieces of science [illustration: george stephenson.] little masterpieces of science edited by george iles invention and discovery _by_ benjamin franklin alexander graham bell michael faraday count rumford joseph henry george stephenson [illustration] new york doubleday, page & company copyright, , by doubleday, page & co. copyright, , by george b. prescott copyright, , by s. s. mcclure co. copyright, , by doubleday, mcclure & co. preface to a good many of us the inventor is the true hero for he multiplies the working value of life. he performs an old task with new economy, as when he devises a mowing-machine to oust the scythe; or he creates a service wholly new, as when he bids a landscape depict itself on a photographic plate. he, and his twin brother, the discoverer, have eyes to read a lesson that nature has held for ages under the undiscerning gaze of other men. where an ordinary observer sees, or thinks he sees, diversity, a franklin detects identity, as in the famous experiment here recounted which proves lightning to be one and the same with a charge of the leyden jar. of a later day than franklin, advantaged therefor by new knowledge and better opportunities for experiment, stood faraday, the founder of modern electric art. his work gave the world the dynamo and motor, the transmission of giant powers, almost without toll, for two hundred miles at a bound. it is, however, in the carriage of but trifling quantities of motion, just enough for signals, that electricity thus far has done its most telling work. among the men who have created the electric telegraph joseph henry has a commanding place. a short account of what he did, told in his own words, is here presented. then follows a narrative of the difficult task of laying the first atlantic cables, a task long scouted as impossible: it is a story which proves how much science may be indebted to unfaltering courage, to faith in ultimate triumph. to give speech the wings of electricity, to enable friends in denver and new york to converse with one another, is a marvel which only familiarity places beyond the pale of miracle. shortly after he perfected the telephone professor bell described the steps which led to its construction. that recital is here reprinted. a recent wonder of electric art is its penetration by a photographic ray of substances until now called opaque. professor röntgen's account of how he wrought this feat forms one of the most stirring chapters in the history of science. next follows an account of the telegraph as it dispenses with metallic conductors altogether, and trusts itself to that weightless ether which brings to the eye the luminous wave. to this succeeds a chapter which considers what electricity stands for as one of the supreme resources of human wit, a resource transcending even flame itself, bringing articulate speech and writing to new planes of facility and usefulness. it is shown that the rapidity with which during a single century electricity has been subdued for human service, illustrates that progress has leaps as well as deliberate steps, so that at last a gulf, all but infinite, divides man from his next of kin. at this point we pause to recall our debt to the physical philosophy which underlies the calculations of the modern engineer. in such an experiment as that of count rumford we observe how the corner-stone was laid of the knowledge that heat is motion, and that motion under whatever guise, as light, electricity, or what not, is equally beyond creation or annihilation, however elusively it may glide from phase to phase and vanish from view. in the mastery of flame for the superseding of muscle, of breeze and waterfall, the chief credit rests with james watt, the inventor of the steam engine. beside him stands george stephenson, who devised the locomotive which by abridging space has lengthened life and added to its highest pleasures. our volume closes by narrating the competition which decided that stephenson's "rocket" was much superior to its rivals, and thus opened a new chapter in the history of mankind. george iles. contents franklin, benjamin lightning identified with electricity franklin explains the action of the leyden phial or jar. suggests lightning-rods. sends a kite into the clouds during a thunderstorm; through the kite-string obtains a spark of lightning which throws into divergence the loose fibres of the string, just as an ordinary electrical discharge would do. faraday, michael preparing the way for the electric dynamo and motor notices the inductive effect in one coil when the circuit in a concentric coil is completed or broken. notices similar effects when a wire bearing a current approaches another wire or recedes from it. rotates a galvanometer needle by an electric pulse. induces currents in coils when the magnetism is varied in their iron or steel cores. observes the lines of magnetic force as iron filings are magnetized. a magnetic bar moved in and out of a coil of wire excites electricity therein,--mechanical motion is converted into electricity. generates a current by spinning a copper plate in a horizontal plane. henry, joseph invention of the electric telegraph improves the electro-magnet of sturgeon by insulating its wire with silk thread, and by disposing the wire in several coils instead of one. experiments with a large electro-magnet excited by nine distinct coils. uses a battery so powerful that electro-magnets are produced one hundred times more energetic than those of sturgeon. arranges a telegraphic circuit more than a mile long and at that distance sounds a bell by means of an electro-magnet. iles, george the first atlantic cables forerunners at new york and dover. gutta-percha the indispensable insulator. wire is used to sheathe the cables. cyrus w. field's project for an atlantic cable. the first cable fails. so does the second cable . a triumph of courage, . the highway smoothed for successors. lessons of the cable. bell, alexander graham the invention of the telephone indebted to his father's study of the vocal organs as they form sounds. examines the helmholtz method for the analysis and synthesis of vocal sounds. suggests the electrical actuation of tuning-forks and the electrical transmission of their tones. distinguishes intermittent, pulsatory and undulatory currents. devises as his first articulating telephone a harp of steel rods thrown into vibration by electro-magnetism. exhibits optically the vibrations of sound, using a preparation of a human ear: is struck by the efficiency of a slight aural membrane. attaches a bit of clock spring to a piece of goldbeater's skin, speaks to it, an audible message is received at a distant and similar device. this contrivance improved is shown at the centennial exhibition, philadelphia, . at first the same kind of instrument transmitted and delivered, a message; soon two distinct instruments were invented for transmitting and for receiving. extremely small magnets suffice. a single blade of grass forms a telephonic circuit. dam, h. j. w. photographing the unseen röntgen indebted to the researches of faraday, clerk-maxwell, hertz, lodge and lenard. the human optic nerve is affected by a very small range in the waves that exist in the ether. beyond the visible spectrum of common light are vibrations which have long been known as heat or as photographically active. crookes in a vacuous bulb produced soft light from high tension electricity. lenard found that rays from a crookes' tube passed through substances opaque to common light. röntgen extended these experiments and used the rays photographically, taking pictures of the bones of the hand through living flesh, and so on. iles, george the wireless telegraph what may follow upon electric induction. telegraphy to a moving train. the preece induction method; its limits. marconi's system. his precursors, hertz, onesti, branly and lodge. the coherer and the vertical wire form the essence of the apparatus. wireless telegraphy at sea. iles, george electricity, what its mastery means: with a review and a prospect electricity does all that fire ever did, does it better, and performs uncounted services impossible to flame. its mastery means as great a forward stride as the subjugation of fire. a minor invention or discovery simply adds to human resources: a supreme conquest as of flame or electricity, is a multiplier and lifts art and science to a new plane. growth is slow, flowering is rapid: progress at times is so quick of pace as virtually to become a leap. the mastery of electricity based on that of fire. electricity vastly wider of range than heat: it is energy in its most available and desirable phase. the telegraph and the telephone contrasted with the signal fire. electricity as the servant of mechanic and engineer. household uses of the current. electricity as an agent of research now examines nature in fresh aspects. the investigator and the commercial exploiter render aid to one another. social benefits of electricity, in telegraphy, in quick travel. the current should serve every city house. rumford, count (benjamin thompson) heat and motion identified observes that in boring a cannon much heat is generated: the longer the boring lasts, the more heat is produced. he argues that since heat without limit may be thus produced by motion, heat must be motion. stephenson, george the "rocket" locomotive and its victory shall it be a system of stationary engines or locomotives? the two best practical engineers of the day are in favour of stationary engines. a test of locomotives is, however, proffered, and george stephenson and his son, robert, discuss how they may best build an engine to win the first prize. they adopt a steam blast to stimulate the draft of the furnace, and raise steam quickly in a boiler having twenty-five small fire-tubes of copper. the "rocket" with a maximum speed of twenty-nine miles an hour distances its rivals. with its load of water its weight was but four and a quarter tons. invention and discovery franklin identifies lightning with electricity [from franklin's works, edited in ten volumes by john bigelow, vol. i, pages - , copyright by g. p. putnam's sons, new york.] dr. stuber, the author of the first continuation of franklin's life, gives this account of the electrical experiments of franklin:-- "his observations he communicated, in a series of letters, to his friend collinson, the first of which is dated march , . in these he shows the power of points in drawing and throwing off the electrical matter, which had hitherto escaped the notice of electricians. he also made the grand discovery of a _plus_ and _minus_, or of a _positive_ and _negative_ state of electricity. we give him the honour of this without hesitation; although the english have claimed it for their countryman, dr. watson. watson's paper is dated january , ; franklin's july , , several months prior. shortly after franklin, from his principles of the _plus_ and _minus_ state, explained in a satisfactory manner the phenomena of the leyden phial, first observed by mr. cuneus, or by professor muschenbroeck, of leyden, which had much perplexed philosophers. he showed clearly that when charged the bottle contained no more electricity than before, but that as much was taken from one side as thrown on the other; and that to discharge it nothing was necessary but to produce a communication between the two sides by which the equilibrium might be restored, and that then no signs of electricity would remain. he afterwards demonstrated by experiments that the electricity did not reside in the coating as had been supposed, but in the pores of the glass itself. after the phial was charged he removed the coating, and found that upon applying a new coating the shock might still be received. in the year , he first suggested his idea of explaining the phenomena of thunder gusts and of _aurora borealis_ upon electric principles. he points out many particulars in which lightning and electricity agree; and he adduces many facts, and reasonings from facts, in support of his positions. "in the same year he conceived the astonishingly bold and grand idea of ascertaining the truth of his doctrine by actually drawing down the lightning, by means of sharp pointed iron rods raised into the regions of the clouds. even in this uncertain state his passion to be useful to mankind displayed itself in a powerful manner. admitting the identity of electricity and lightning, and knowing the power of points in repelling bodies charged with electricity, and in conducting fires silently and imperceptibly, he suggested the idea of securing houses, ships and the like from being damaged by lightning, by erecting pointed rods that should rise some feet above the most elevated part, and descend some feet into the ground or water. the effect of these he concluded would be either to prevent a stroke by repelling the cloud beyond the striking distance or by drawing off the electrical fire which it contained; or, if they could not effect this they would at least conduct the electrical matter to the earth without any injury to the building. "it was not until the summer of that he was enabled to complete his grand and unparalleled discovery by experiment. the plan which he had originally proposed was, to erect, on some high tower or elevated place, a sentry-box from which should rise a pointed iron rod, insulated by being fixed in a cake of resin. electrified clouds passing over this would, he conceived, impart to it a portion of their electricity which would be rendered evident to the senses by sparks being emitted when a key, the knuckle, or other conductor, was presented to it. philadelphia at this time afforded no opportunity of trying an experiment of this kind. while franklin was waiting for the erection of a spire, it occurred to him that he might have more ready access to the region of clouds by means of a common kite. he prepared one by fastening two cross sticks to a silk handkerchief, which would not suffer so much from the rain as paper. to the upright stick was affixed an iron point. the string was, as usual, of hemp, except the lower end, which was silk. where the hempen string terminated, a key was fastened. with this apparatus, on the appearance of a thundergust approaching, he went out into the commons, accompanied by his son, to whom alone he communicated his intentions, well knowing the ridicule which, too generally for the interest of science, awaits unsuccessful experiments in philosophy. he placed himself under a shed, to avoid the rain; his kite was raised, a thunder-cloud passed over it, no sign of electricity appeared. he almost despaired of success, when suddenly he observed the loose fibres of his string to move towards an erect position. he now presented his knuckle to the key and received a strong spark. how exquisite must his sensations have been at this moment! on his experiment depended the fate of his theory. if he succeeded, his name would rank high among those who had improved science; if he failed, he must inevitably be subjected to the derision of mankind, or, what is worse, their pity, as a well-meaning man, but a weak, silly projector. the anxiety with which he looked for the result of his experiment may easily be conceived. doubts and despair had begun to prevail, when the fact was ascertained, in so clear a manner, that even the most incredulous could no longer withhold their assent. repeated sparks were drawn from the key, a phial was charged, a shock given, and all the experiments made which are usually performed with electricity." faraday's discoveries leading up to the electric dynamo and motor [michael faraday was for many years professor of natural philosophy at the royal institution, london, where his researches did more to subdue electricity to the service of man than those of any other physicist who ever lived. "faraday as a discoverer," by professor john tyndall (his successor) depicts a mind of the rarest ability and a character of the utmost charm. this biography is published by d. appleton & co., new york: the extracts which follow are from the third chapter.] in we have faraday at the climax of his intellectual strength, forty years of age, stored with knowledge and full of original power. through reading, lecturing, and experimenting, he had become thoroughly familiar with electrical science: he saw where light was needed and expansion possible. the phenomena of ordinary electric induction belonged, as it were, to the alphabet of his knowledge: he knew that under ordinary circumstances the presence of an electrified body was sufficient to excite, by induction, an unelectrified body. he knew that the wire which carried an electric current was an electrified body, and still that all attempts had failed to make it excite in other wires a state similar to its own. what was the reason of this failure? faraday never could work from the experiments of others, however clearly described. he knew well that from every experiment issues a kind of radiation, luminous, in different degrees to different minds, and he hardly trusted himself to reason upon an experiment that he had not seen. in the autumn of he began to repeat the experiments with electric currents, which, up to that time, had produced no positive result. and here, for the sake of younger inquirers, if not for the sake of us all, it is worth while to dwell for a moment on a power which faraday possessed in an extraordinary degree. he united vast strength with perfect flexibility. his momentum was that of a river, which combines weight and directness with the ability to yield to the flexures of its bed. the intentness of his vision in any direction did not apparently diminish his power of perception in other directions; and when he attacked a subject, expecting results, he had the faculty of keeping his mind alert, so that results different from those which he expected should not escape him through pre-occupation. he began his experiments "on the induction of electric currents" by composing a helix of two insulated wires, which were wound side by side round the same wooden cylinder. one of these wires he connected with a voltaic battery of ten cells, and the other with a sensitive galvanometer. when connection with the battery was made, and while the current flowed, no effect whatever was observed at the galvanometer. but he never accepted an experimental result, until he had applied to it the utmost power at his command. he raised his battery from ten cells to one hundred and twenty cells, but without avail. the current flowed calmly through the battery wire without producing, during its flow, any sensible result upon the galvanometer. "during its flow," and this was the time when an effect was expected--but here faraday's power of lateral vision, separating, as it were from the line of expectation, came into play--he noticed that a feeble movement of the needle always occurred at the moment when he made contact with the battery; that the needle would afterwards return to its former position and remain quietly there unaffected by the _flowing_ current. at the moment, however, when the circuit was interrupted the needle again moved, and in a direction opposed to that observed on the completion of the circuit. this result, and others of a similar kind, led him to the conclusion "that the battery current through the one wire did in reality induce a similar current through the other; but that it continued for an instant only, and partook more of the nature of the electric wave from a common leyden jar than of the current from a voltaic battery." the momentary currents thus generated were called _induced currents_, while the current which generated them was called the _inducing_ current. it was immediately proved that the current generated at making the circuit was always opposed in direction to its generator, while that developed on the rupture of the circuit coincided in direction with the inducing current. it appeared as if the current on its first rush through the primary wire sought a purchase in the secondary one, and, by a kind of kick, impelled backward through the latter an electric wave, which subsided as soon as the primary current was fully established. faraday, for a time, believed that the secondary wire, though quiescent when the primary current had been once established, was not in its natural condition, its return to that condition being declared by the current observed at breaking the circuit. he called this hypothetical state of the wire the _electro-tonic state_: he afterwards abandoned this hypothesis, but seemed to return to it in after life. the term electro-tonic is also preserved by professor du bois reymond to express a certain electric condition of the nerves, and professor clerk maxwell has ably defined and illustrated the hypothesis in the tenth volume of the "transactions of the cambridge philosophical society." the mere approach of a wire forming a closed curve to a second wire through which a voltaic current flowed was then shown by faraday to be sufficient to arouse in the neutral wire an induced current, opposed in direction to the inducing current; the withdrawal of the wire also generated a current having the same direction as the inducing current; those currents existed only during the time of approach or withdrawal, and when neither the primary nor the secondary wire was in motion, no matter how close their proximity might be, no induced current was generated. faraday has been called a purely inductive philosopher. a great deal of nonsense is, i fear, uttered in this land of england about induction and deduction. some profess to befriend the one, some the other, while the real vocation of an investigator, like faraday, consists in the incessant marriage of both. he was at this time full of the theory of ampère, and it cannot be doubted that numbers of his experiments were executed merely to test his deductions from that theory. starting from the discovery of oersted, the celebrated french philosopher had shown that all the phenomena of magnetism then known might be reduced to the mutual attractions and repulsions of electric currents. magnetism had been produced from electricity, and faraday, who all his life long entertained a strong belief in such reciprocal actions, now attempted to effect the evolution of electricity from magnetism. round a welded iron ring he placed two distinct coils of covered wire, causing the coils to occupy opposite halves of the ring. connecting the ends of one of the coils with a galvanometer, he found that the moment the ring was magnetized, by sending a current through _the other coil_, the galvanometer needle whirled round four or five times in succession. the action, as before, was that of a pulse, which vanished immediately. on interrupting the current, a whirl of the needle in the opposite direction occurred. it was only during the time of magnetization or demagnetization that these effects were produced. the induced currents declared a _change_ of condition only, and they vanished the moment the act of magnetization or demagnetization was complete. the effects obtained with the welded ring were also obtained with straight bars of iron. whether the bars were magnetized by the electric current, or were excited by the contact of permanent steel magnets, induced currents were always generated during the rise, and during the subsidence of the magnetism. the use of iron was then abandoned, and the same effects were obtained by merely thrusting a permanent steel magnet into a coil of wire. a rush of electricity through the coil accompanied the insertion of the magnet; an equal rush in the opposite direction accompanied its withdrawal. the precision with which faraday describes these results, and the completeness with which he defined the boundaries of his facts, are wonderful. the magnet, for example, must not be passed quite through the coil, but only half through, for if passed wholly through, the needle is stopped as by a blow, and then he shows how this blow results from a reversal of the electric wave in the helix. he next operated with the powerful permanent magnet of the royal society, and obtained with it, in an exalted degree, all the foregoing phenomena. and now he turned the light of these discoveries upon the darkest physical phenomenon of that day. arago had discovered in , that a disk of non-magnetic metal had the power of bringing a vibrating magnetic needle suspended over it rapidly to rest; and that on causing the disk to rotate the magnetic needle rotated along with it. when both were quiescent, there was not the slightest measurable attraction or repulsion exerted between the needle and the disk; still when in motion the disk was competent to drag after it, not only a light needle, but a heavy magnet. the question had been probed and investigated with admirable skill by both arago and ampère, and poisson had published a theoretic memoir on the subject; but no cause could be assigned for so extraordinary an action. it had also been examined in this country by two celebrated men, mr. babbage and sir john herschel; but it still remained a mystery. faraday always recommended the suspension of judgment in cases of doubt. "i have always admired," he says, "the prudence and philosophical reserve shown by m. arago in resisting the temptations to give a theory of the effect he had discovered, so long as he could not devise one which was perfect in its application, and in refusing to assent to the imperfect theories of others." now, however, the time for theory had come. faraday saw mentally the rotating disk, under the operation of the magnet, flooded with his induced currents, and from the known laws of interaction between currents and magnets he hoped to deduce the motion observed by arago. that hope he realized, showing by actual experiment that when his disk rotated currents passed through it, their position and direction being such as must, in accordance with the established laws of electro-magnetic action, produce the observed rotation. introducing the edge of his disk between the poles of the large horseshoe magnet of the royal society, and connecting the axis and the edge of the disk, each by a wire with a galvanometer, he obtained, when the disk was turned round, a constant flow of electricity. the direction of the current was determined by the direction of the motion, the current being reversed when the rotation was reversed. he now states the law which rules the production of currents in both disks and wires, and in so doing uses, for the first time, a phrase which has since become famous. when iron filings are scattered over a magnet, the particles of iron arrange themselves in certain determined lines called magnetic curves. in , faraday for the first time called these curves "lines of magnetic force;" and he showed that to produce induced currents neither approach to nor withdrawal from a magnetic source, or centre, or pole, was essential, but that it was only necessary to cut appropriately the lines of magnetic force. faraday's first paper on magneto-electric induction, which i have here endeavoured to condense, was read before the royal society on the th of november, . on january , , he communicated to the royal society a second paper on "terrestrial magneto-electric induction," which was chosen as the bakerian lecture for the year. he placed a bar of iron in a coil of wire, and lifting the bar into the direction of the dipping needle, he excited by this action a current in the coil. on reversing the bar, a current in the opposite direction rushed through the wire. the same effect was produced, when, on holding the helix in the line of dip, a bar of iron was thrust into it. here, however, the earth acted on the coil through the intermediation of the bar of iron. he abandoned the bar and simply set a copper-plate spinning in a horizontal plane; he knew that the earth's lines of magnetic force then crossed the plate at an angle of about °. when the plate spun round, the lines of force were intersected and induced currents generated, which produced their proper effect when carried from the plate to the galvanometer. "when the plate was in the magnetic meridian, or in any other plane coinciding with the magnetic dip, then its rotation produced no effect upon the galvanometer." at the suggestion of a mind fruitful in suggestions of a profound and philosophic character--i mean that of sir john herschel--mr. barlow, of woolwich, had experimented with a rotating iron shell. mr. christie had also performed an elaborate series of experiments on a rotating iron disk. both of them had found that when in rotation the body exercised a peculiar action upon the magnetic needle, deflecting it in a manner which was not observed during quiescence; but neither of them was aware at the time of the agent which produced this extraordinary deflection. they ascribed it to some change in the magnetism of the iron shell and disk. but faraday at once saw that his induced currents must come into play here, and he immediately obtained them from an iron disk. with a hollow brass ball, moreover, he produced the effects obtained by mr. barlow. iron was in no way necessary: the only condition of success was that the rotating body should be of a character to admit of the formation of currents in its substance: it must, in other words, be a conductor of electricity. the higher the conducting power the more copious were the currents. he now passes from his little brass globe to the globe of the earth. he plays like a magician with the earth's magnetism. he sees the invisible lines along which its magnetic action is exerted and sweeping his wand across these lines evokes this new power. placing a simple loop of wire round a magnetic needle he bends its upper portion to the west: the north pole of the needle immediately swerves to the east: he bends his loop to the east, and the north poles moves to the west. suspending a common bar magnet in a vertical position, he causes it to spin round its own axis. its pole being connected with one end of a galvanometer wire, and its equator with the other end, electricity rushes round the galvanometer from the rotating magnet. he remarks upon the "_singular independence_" of the magnetism and the body of the magnet which carries it. the steel behaves as if it were isolated from its own magnetism. and then his thoughts suddenly widen, and he asks himself whether the rotating earth does not generate induced currents as it turns round its axis from west to east. in his experiment with the twirling magnet the galvanometer wire remained at rest; one portion of the circuit was in motion _relatively_ to _another portion_. but in the case of the twirling planet the galvanometer wire would necessarily be carried along with the earth; there would be no relative motion. what must be the consequence? take the case of a telegraph wire with its two terminal plates dipped into the earth, and suppose the wire to lie in the magnetic meridian. the ground underneath the wire is influenced like the wire itself by the earth's rotation; if a current from south to north be generated in the wire, a similar current from south to north would be generated in the earth under the wire; these currents would run against the same terminal plates, and thus neutralize each other. this inference appears inevitable, but his profound vision perceived its possible invalidity. he saw that it was at least possible that the difference of conducting power between the earth and the wire might give one an advantage over the other, and that thus a residual or differential current might be obtained. he combined wires of different materials, and caused them to act in opposition to each other, but found the combination ineffectual. the more copious flow in the better conductor was exactly counterbalanced by the resistance of the worst. still, though experiment was thus emphatic, he would clear his mind of all discomfort by operating on the earth itself. he went to the round lake near kensington palace, and stretched four hundred and eighty feet of copper wire, north and south, over the lake, causing plates soldered to the wire at its ends to dip into the water. the copper wire was severed at the middle, and the severed ends connected with a galvanometer. no effect whatever was observed. but though quiescent water gave no effect, moving water might. he therefore worked at london bridge for three days during the ebb and flow of the tide, but without any satisfactory result. still he urges, "theoretically it seems a necessary consequence, that where water is flowing there electric currents should be formed. if a line be imagined passing from dover to calais through the sea, and returning through the land, beneath the water, to dover, it traces out a circuit of conducting matter one part of which, when the water moves up or down the channel, is cutting the magnetic curves of the earth, while the other is relatively at rest.... there is every reason to believe that currents do run in the general direction of the circuit described, either one way or the other, according as the passage of the waters is up or down the channel." this was written before the submarine cable was thought of, and he once informed me that actual observation upon that cable had been found to be in accordance with his theoretic deduction. three years subsequent to the publication of these researches, that is to say on january , , faraday read before the royal society a paper "on the influence by induction of an electric current upon itself." a shock and spark of a peculiar character had been observed by a young man named william jenkin, who must have been a youth of some scientific promise, but who, as faraday once informed me, was dissuaded by his own father from having anything to do with science. the investigation of the fact noticed by mr. jenkin led faraday to the discovery of the _extra current_, or the current _induced in the primary wire itself_ at the moments of making and breaking contact, the phenomena of which he described and illustrated in the beautiful and exhaustive paper referred to. seven and thirty years have passed since the discovery of magneto-electricity; but, if we except the _extra current_, until quite recently nothing of moment was added to the subject. faraday entertained the opinion that the discoverer of a great law or principle had a right to the "spoils"--this was his term--arising from its illustration; and guided by the principle he had discovered, his wonderful mind, aided by his wonderful ten fingers, overran in a single autumn this vast domain, and hardly left behind him the shred of a fact to be gathered by his successors. and here the question may arise in some minds, what is the use of it all? the answer is, that if man's intellectual nature thirsts for knowledge then knowledge is useful because it satisfies this thirst. if you demand practical ends, you must, i think, expand your definition of the term practical, and make it include all that elevates and enlightens the intellect, as well as all that ministers to the bodily health and comfort of men. still, if needed, an answer of another kind might be given to the question "what is its use?" as far as electricity has been applied for medical purposes, it has been almost exclusively faraday's electricity. you have noticed those lines of wire which cross the streets of london. it is faraday's currents that speed from place to place through these wires. approaching the point of dungeness, the mariner sees an unusually brilliant light, and from the noble lighthouse of la hève the same light flashes across the sea. these are faraday's sparks exalted by suitable machinery to sun-like splendour. at the present moment the board of trade and the brethren of the trinity house, as well as the commissioners of northern lights, are contemplating the introduction of the magneto-electric light at numerous points upon our coasts; and future generations will be able to refer to those guiding stars in answer to the question, what has been the practical use of the labours of faraday? but i would again emphatically say, that his work needs no justification, and that if he had allowed his vision to be disturbed by considerations regarding the practical use of his discoveries, those discoveries would never have been made by him. "i have rather," he writes in , "been desirous of discovering new facts and new relations dependent on magneto-electric induction, than of exalting the force of those already obtained; being assured that the latter would find their full development hereafter." in , when lecturing before a private society in london on the element chlorine, faraday thus expresses himself with reference to this question of utility. "before leaving this subject, i will point out the history of this substance as an answer to those who are in the habit of saying to every new fact, 'what is its use?' dr. franklin says to such, 'what is the use of an infant?' the answer of the experimentalist is, 'endeavour to make it useful.' when scheele discovered this substance, it appeared to have no use; it was in its infancy and useless state, but having grown up to maturity, witness its powers, and see what endeavours to make it useful have done." professor joseph henry's invention of the electric telegraph [in the regents of the smithsonian institution, washington, d. c., at the instance of their secretary, professor joseph henry, took evidence with respect to his claims as inventor of the electric telegraph. the essential paragraphs of professor henry's statement are taken from the proceedings of the board of regents of the smithsonian institution, washington, .] there are several forms of the electric telegraph; first, that in which frictional electricity has been proposed to produce sparks and motion of pith balls at a distance. second, that in which galvanism has been employed to produce signals by means of bubbles of gas from the decomposition of water. third, that in which electro-magnetism is the motive power to produce motion at a distance; and again, of the latter there are two kinds of telegraphs, those in which the intelligence is indicated by the motion of a magnetic needle, and those in which sounds and permanent signs are made by the attraction of an electro-magnet. the latter is the class to which mr. morse's invention belongs. the following is a brief exposition of the several steps which led to this form of the telegraph. the first essential fact which rendered the electro-magnetic telegraph possible was discovered by oersted, in the winter of -' . it is illustrated by figure , in which the magnetic needle is deflected by the action of a current of galvanism transmitted through the wire a b. [illustration: fig. ] the second fact of importance, discovered in , by arago and davy, is illustrated in fig. . it consists in this, that while a current of galvanism is passing through a copper wire a b, it is magnetic, it attracts iron filings and not those of copper or brass, and is capable of developing magnetism in soft iron. [illustration: fig. ] the next important discovery, also made in , by ampère, was that two wires through which galvanic currents are passing in the same direction attract, and in the opposite direction, repel, each other. on this fact ampère founded his celebrated theory, that magnetism consists merely in the attraction of electrical currents revolving at right angles to the line joining the two poles of the magnet. the magnetization of a bar of steel or iron, according to this theory consists in establishing within the metal by induction a series of electrical currents, all revolving in the same direction at right angles to the axis or length of the bar. [illustration: fig. ] it was this theory which led arago, as he states, to adopt the method of magnetizing sewing needles and pieces of steel wire, shown in fig. . this method consists in transmitting a current of electricity through a helix surrounding the needle or wire to be magnetised. for the purpose of insulation the needle was enclosed in a glass tube, and the several turns of the helix were at a distance from each other to insure the passage of electricity through the whole length of the wire, or, in other words, to prevent it from seeking a shorter passage by cutting across from one spire to another. the helix employed by arago obviously approximates the arrangement required by the theory of ampère, in order to develop by induction the magnetism of the iron. by an attentive perusal of the original account of the experiments of arago, it will be seen that, properly speaking, he made no electro-magnet, as has been asserted by morse and others; his experiments were confined to the magnetism of iron filings, to sewing needles and pieces of steel wire of the diameter of a millimetre, or of about the thickness of a small knitting needle. [illustration: fig. ] mr. sturgeon, in , made an important step in advance of the experiments of arago, and produced what is properly known as the electro-magnet. he bent a piece of iron _wire_ into the form of a horseshoe, covered it with varnish to insulate it, and surrounded it with a helix, of which the spires were at a distance. when a current of galvanism was passed through the helix from a small battery of a single cup the iron wire became magnetic, and continued so during the passage of the current. when the current was interrupted the magnetism disappeared, and thus was produced the first temporary soft iron magnet. the electro-magnet of sturgeon is shown in fig. . by comparing figs. and it will be seen that the helix employed by sturgeon was of the same kind as that used by arago; instead however, of a straight steel wire inclosed in a tube of glass, the former employed a bent wire of soft iron. the difference in the arrangement at first sight might appear to be small, but the difference in the results produced was important, since the temporary magnetism developed in the arrangement of sturgeon was sufficient to support a weight of several pounds, and an instrument was thus produced of value in future research. [illustration: fig. ] the next improvement was made by myself. after reading an account of the galvanometer of schweigger, the idea occurred to me that a much nearer approximation to the requirements of the theory of ampère could be attained by insulating the conducting wire itself, instead of the rod to be magnetized, and by covering the whole surface of the iron with a series of coils in close contact. this was effected by insulating a long wire with silk thread, and winding this around the rod of iron in close coils from one end to the other. the same principle was extended by employing a still longer insulated wire, and winding several strata of this over the first, care being taken to insure the insulation between each stratum by a covering of silk ribbon. by this arrangement the rod was surrounded by a compound helix formed of a long wire of many coils, instead of a single helix of a few coils, (fig. ). in the arrangement of arago and sturgeon the several turns of wire were not precisely at right angles to the axis of the rod, as they should be, to produce the effect required by the theory, but slightly oblique, and therefore each tended to develop a separate magnetism not coincident with the axis of the bar. but in winding the wire over itself, the obliquity of the several turns compensated each other, and the resultant action was at right angles to the bar. the arrangement then introduced by myself was superior to those of arago and sturgeon, first in the greater multiplicity of turns of wire, and second in the better application of these turns to the development of magnetism. the power of the instrument with the same amount of galvanic force, was by this arrangement several times increased. the maximum effect, however, with this arrangement and a single battery was not yet obtained. after a certain length of wire had been coiled upon the iron, the power diminished with a further increase of the number of turns. this was due to the increased resistance which the longer wire offered to the conduction of electricity. two methods of improvement therefore suggested themselves. the first consisted, not in increasing the length of the coil, but in using a number of separate coils on the same piece of iron. by this arrangement the resistance to the conduction of the electricity was diminished and a greater quantity made to circulate around the iron from the same battery. the second method of producing a similar result consisted in increasing the number of elements of the battery, or, in other words, the projectile force of the electricity, which enabled it to pass through an increased number of turns of wire, and thus, by increasing the length of the wire, to develop the maximum power of the iron. [illustration: fig. ] to test these principles on a larger scale, the experimental magnet was constructed, which is shown in fig. . in this a number of compound helices were placed on the same bar, their ends left projecting, and so numbered that they could be all united into one long helix, or variously combined in sets of lesser length. from a series of experiments with this and other magnets it was proved that, in order to produce the greatest amount of magnetism from a battery of a single cup, a number of helices is required; but when a compound battery is used, then one long wire must be employed, making many turns around the iron, the length of wire and consequently the number of turns being commensurate with the projectile power of the battery. in describing the results of my experiments, the terms _intensity_ and _quantity_ magnets were introduced to avoid circumlocution, and were intended to be used merely in a technical sense. by the _intensity_ magnet i designated a piece of soft iron, so surrounded with wire that its magnetic power could be called into operation by an _intensity_ battery, and by a _quantity_ magnet, a piece of iron so surrounded by a number of separate coils, that its magnetism could be fully developed by a _quantity_ battery. i was the first to point out this connection of the two kinds of the battery with the two forms of the magnet, in my paper in _silliman's journal_, january, , and clearly to state that when magnetism was to be developed by means of a compound battery, one long coil was to be employed, and when the maximum effect was to be produced by a single battery, a number of single strands were to be used. these steps in the advance of electro-magnetism, though small, were such as to interest and astonish the scientific world. with the same battery used by mr. sturgeon, at least a hundred times more magnetism was produced than could have been obtained by his experiment. the developments were considered at the time of much importance in a scientific point of view, and they subsequently furnished the means by which magneto-electricity, the phenomena of dia-magnetism, and the magnetic effects on polarized light were discovered. they gave rise to the various forms of electro-magnetic machines which have since exercised the ingenuity of inventors in every part of the world, and were of immediate applicability in the introduction of the magnet to telegraphic purposes. neither the electro-magnet of sturgeon nor any electro-magnet ever made previous to my investigations was applicable to transmitting power to a distance. the principles i have developed were properly appreciated by the scientific mind of dr. gale, and applied by him to operate mr. morse's machine at a distance. previous to my investigations the means of developing magnetism in soft iron were imperfectly understood. the electro-magnet made by sturgeon, and copied by dana, of new york, was an imperfect quantity magnet, the feeble power of which was developed by a single battery. it was entirely inapplicable to a long circuit with an intensity battery, and no person possessing the requisite scientific knowledge, would have attempted to use it in that connection after reading my paper. in sending a message to a distance, two circuits are employed, the first a long circuit through which the electricity is sent to the distant station to bring into action the second, a short one, in which is the local battery and magnet for working the machine. in order to give projectile force sufficient to send the power to a distance, it is necessary to use an intensity battery in the long circuit, and in connection with this, at the distant station, a magnet surrounded with many turns of one long wire must be employed to receive and multiply the effect of the current enfeebled by its transmission through the long conductor. in the local or short circuit either an intensity or a quantity magnet may be employed. if the first be used, then with it a compound battery will be required; and, therefore on account of the increased resistance due to the greater quantity of acid, a less amount of work will be performed by a given amount of material; and, consequently, though this arrangement is practicable it is by no means economical. in my original paper i state that the advantages of a greater conducting power, from using several wires in the quantity magnet, may, in a less degree, be obtained by substituting for them one large wire; but in this case, on account of the greater obliquity of the spires and other causes, the magnetic effect would be less. in accordance with these principles, the receiving magnet, or that which is introduced into the long circuit, consists of a horseshoe magnet surrounded with many hundred turns of a single long wire, and is operated with a battery of from twelve to twenty-four elements or more, while in the local circuit it is customary to employ a battery of one or two elements with a much thicker wire and fewer turns. it will, i think, be evident to the impartial reader that these were improvements in the electro-magnet, which first rendered it adequate to the transmission of mechanical power to a distance; and had i omitted all allusion to the telegraph in my paper, the conscientious historian of science would have awarded me some credit, however small might have been the advance which i made. arago and sturgeon, in the accounts of their experiments, make no mention of the telegraph, and yet their names always have been and will be associated with the invention. i briefly, however, called attention to the fact of the applicability of my experiments to the construction of the telegraph; but not being familiar with the history of the attempts made in regard to this invention, i called it "barlow's project," while i ought to have stated that mr. barlow's investigation merely tended to disprove the possibility of a telegraph. i did not refer exclusively to the needle telegraph when, in my paper, i stated that the _magnetic_ action of a current from a trough is at least not sensibly diminished by passing through a long wire. this is evident from the fact that the immediate experiment from which this deduction was made was by means of an electro-magnet and not by means of a needle galvanometer. [illustration: fig. ] at the conclusion of the series of experiments which i described in _silliman's journal_, there were two applications of the electro-magnet in my mind: one the production of a machine to be moved by electro-magnetism, and the other the transmission of or calling into action power at a distance. the first was carried into execution in the construction of the machine described in _silliman's journal_, vol. xx, , and for the purpose of experimenting in regard to the second, i arranged around one of the upper rooms in the albany academy a wire of more than a mile in length, through which i was enabled to make signals by sounding a bell, (fig. .) the mechanical arrangement for effecting this object was simply a steel bar, permanently magnetized, of about ten inches in length, supported on a pivot, and placed with its north end between the two arms of a horseshoe magnet. when the latter was excited by the current, the end of the bar thus placed was attracted by one arm of the horseshoe, and repelled by the other, and was thus caused to move in a horizontal plane and its further extremity to strike a bell suitably adjusted. i also devised a method of breaking a circuit, and thereby causing a large weight to fall. it was intended to illustrate the practicability of calling into action a great power at a distance capable of producing mechanical effects; but as a description of this was not printed, i do not place it in the same category with the experiments of which i published an account, or the facts which could be immediately deduced from my papers in _silliman's journal_. from a careful investigation of the history of electro-magnetism in its connection with the telegraph, the following facts may be established: . previous to my investigations the means of developing magnetism in soft iron were imperfectly understood, and the electro-magnet which then existed was inapplicable to the transmission of power to a distance. . i was the first to prove by actual experiment that, in order to develop magnetic power at a distance, a galvanic battery of intensity must be employed to project the current through the long conductor, and that a magnet surrounded by many turns of one long wire must be used to receive this current. . i was the first actually to magnetize a piece of iron at a distance, and to call attention to the fact of the applicability of my experiments to the telegraph. . i was the first to actually sound a bell at a distance by means of the electro-magnet. . the principles i had developed were applied by dr. gale to render morse's machine effective at a distance. the first atlantic cables george iles [from "flame, electricity and the camera," copyright doubleday, page & co., new york.] electric telegraphy on land has put a vast distance between itself and the mechanical signalling of chappé, just as the scope and availability of the french invention are in high contrast with the rude signal fires of the primitive savage. as the first land telegraphs joined village to village, and city to city, the crossing of water came in as a minor incident; the wires were readily committed to the bridges which spanned streams of moderate width. where a river or inlet was unbridged, or a channel was too wide for the roadway of the engineer, the question arose, may we lay an electric wire under water? with an ordinary land line, air serves as so good a non-conductor and insulator that as a rule cheap iron may be employed for the wire instead of expensive copper. in the quest for non-conductors suitable for immersion in rivers, channels, and the sea, obstacles of a stubborn kind were confronted. to overcome them demanded new materials, more refined instruments, and a complete revision of electrical philosophy. as far back as , francisco salva had recommended to the academy of sciences, barcelona, the covering of subaqueous wires by resin, which is both impenetrable by water and a non-conductor of electricity. insulators, indeed, of one kind and another, were common enough, but each of them was defective in some quality indispensable for success. neither glass nor porcelain is flexible, and therefore to lay a continuous line of one or the other was out of the question. resin and pitch were even more faulty, because extremely brittle and friable. what of such fibres as hemp or silk, if saturated with tar or some other good non-conductor? for very short distances under still water they served fairly well, but any exposure to a rocky beach with its chafing action, any rub by a passing anchor, was fatal to them. what the copper wire needed was a covering impervious to water, unchangeable in composition by time, tough of texture, and non-conducting in the highest degree. fortunately all these properties are united in gutta-percha: they exist in nothing else known to art. gutta-percha is the hardened juice of a large tree (_isonandra gutta_) common in the malay archipelago; it is tough and strong, easily moulded when moderately heated. in comparison with copper it is but one , , , , , , th as conductive. as without gutta-percha there could be no ocean telegraphy, it is worth while recalling how it came within the purview of the electrical engineer. in josé d'almeida, a portuguese engineer, presented to the royal asiatic society, london, the first specimens of gutta-percha brought to europe. a few months later, dr. w. montgomerie, a surgeon, gave other specimens to the society of arts, of london, which exhibited them; but it was four years before the chief characteristic of the gum was recognized. in mr. s. t. armstrong of new york, during a visit to london, inspected a pound or two of gutta-percha, and found it to be twice as good a non-conductor as glass. the next year, through his instrumentality, a cable covered with this new insulator was laid between new york and jersey city; its success prompted mr armstrong to suggest that a similarly protected cable be submerged between america and europe. eighteen years of untiring effort, impeded by the errors inevitable to the pioneer, stood between the proposal and its fulfilment. in the messrs. siemens laid under water in the port of kiel a wire covered with seamless gutta-percha, such as, beginning with , they had employed for subterranean conductors. this particular wire was not used for telegraphy, but formed part of a submarine-mine system. in mr. c. v. walker laid an experimental line in the english channel; he proved the possibility of signalling for two miles through a wire covered with gutta-percha, and so prepared the way for a venture which joined the shores of france and england. [illustration: fig. .--calais-dover cable, ] in a cable twenty-five miles in length was laid from dover to calais, only to prove worthless from faulty insulation and the lack of armour against dragging anchors and fretting rocks. in the experiment was repeated with success. the conductor now was not a single wire of copper, but four wires, wound spirally, so as to combine strength with flexibility; these were covered with gutta-percha and surrounded with tarred hemp. as a means of imparting additional strength, ten iron wires were wound round the hemp--a feature which has been copied in every subsequent cable (fig. ). the engineers were fast learning the rigorous conditions of submarine telegraphy; in its essentials the dover-calais line continues to be the type of deep-sea cables to-day. the success of the wire laid across the british channel incited other ventures of the kind. many of them, through careless construction or unskilful laying, were utter failures. at last, in , a submarine line miles in length gave excellent service, as it united varna with constantinople; this was the greatest length of satisfactory cable until the submergence of an atlantic line. in cyrus w. field of new york opened a new chapter in electrical enterprise as he resolved to lay a cable between ireland and newfoundland, along the shortest line that joins europe to america. he chose valentia and heart's content, a little more than , miles apart, as his termini, and at once began to enlist the co-operation of his friends. although an unfaltering enthusiast when once his great idea had possession of him, mr. field was a man of strong common sense. from first to last he went upon well-ascertained facts; when he failed he did so simply because other facts, which he could not possibly know, had to be disclosed by costly experience. messrs. whitehouse and bright, electricians to his company, were instructed to begin a preliminary series of experiments. they united a continuous stretch of wires laid beneath land and water for a distance of , miles, and found that through this extraordinary circuit they could transmit as many as four signals per second. they inferred that an atlantic cable would offer but little more resistance, and would therefore be electrically workable and commercially lucrative. in a cable was forthwith manufactured, divided in halves, and stowed in the holds of the _niagara_ of the united states navy, and the _agamemnon_ of the british fleet. the _niagara_ sailed from ireland; the sister ship proceeded to newfoundland, and was to meet her in mid-ocean. when the _niagara_ had run out miles of her cable it snapped under a sudden increase of strain at the paying-out machinery; all attempts at recovery were unavailing, and the work for that year was abandoned. the next year it was resumed, a liberal supply of new cable having been manufactured to replace the lost section, and to meet any fresh emergency that might arise. a new plan of voyages was adopted: the vessels now sailed together to mid-sea, uniting there both portions of the cable; then one ship steamed off to ireland, the other to the newfoundland coast. both reached their destinations on the same day, august , , and, feeble and irregular though it was, an electric pulse for the first time now bore a message from hemisphere to hemisphere. after despatches had passed through the wire it became silent forever. in one of these despatches from london, the war office countermanded the departure of two regiments about to leave canada for england, which saved an outlay of about $ , . this widely quoted fact demonstrated with telling effect the value of cable telegraphy. now followed years of struggle which would have dismayed any less resolute soul than mr. field. the civil war had broken out, with its perils to the union, its alarms and anxieties for every american heart. but while battleships and cruisers were patrolling the coast from maine to florida, and regiments were marching through washington on their way to battle, there was no remission of effort on the part of the great projector. indeed, in the misunderstandings which grew out of the war, and that at one time threatened international conflict, he plainly saw how a cable would have been a peace-maker. a single word of explanation through its wire, and angry feelings on both sides of the ocean would have been allayed at the time of the _trent_ affair. in this conviction he was confirmed by the english press; the london _times_ said: "we nearly went to war with america because we had no telegraph across the atlantic." in the british government had appointed a committee of eminent engineers to inquire into the feasibility of an atlantic telegraph, with a view to ascertaining what was wanting for success, and with the intention of adding to its original aid in case the enterprise were revived. in july, , this committee presented a report entirely favourable in its terms, affirming "that a well-insulated cable, properly protected, of suitable specific gravity, made with care, tested under water throughout its progress with the best-known apparatus, and paid into the ocean with the most improved machinery, possesses every prospect of not only being successfully laid in the first instance, but may reasonably be relied upon to continue for many years in an efficient state for the transmission of signals." taking his stand upon this endorsement, mr. field now addressed himself to the task of raising the large sum needed to make and lay a new cable which should be so much better than the old ones as to reward its owners with triumph. he found his english friends willing to venture the capital required, and without further delay the manufacture of a new cable was taken in hand. in every detail the recommendations of the scientific committee were carried out to the letter, so that the cable of was incomparably superior to that of . first, the central copper wire, which was the nerve along which the lightning was to run, was nearly three times larger than before. the old conductor was a strand consisting of seven fine wires, six laid around one, and weighed but pounds to the mile. the new was composed of the same number of wires, but weighed pounds to the mile. it was made of the finest copper obtainable. to secure insulation, this conductor was first embedded in chatterton's compound, a preparation impervious to water, and then covered with four layers of gutta-percha, which were laid on alternately with four thin layers of chatterton's compound. the old cable had but three coatings of gutta-percha, with nothing between. its entire insulation weighed but pounds to the mile, while that of the new weighed pounds.[ ] the exterior wires, ten in number, were of bessemer steel, each separately wound in pitch-soaked hemp yarn, the shore ends specially protected by thirty-six wires girdling the whole. here was a combination of the tenacity of steel with much of the flexibility of rope. the insulation of the copper was so excellent as to exceed by a hundredfold that of the core of --which, faulty though it was, had, nevertheless, sufficed for signals. so much inconvenience and risk had been encountered in dividing the task of cable-laying between two ships that this time it was decided to charter a single vessel, the _great eastern_, which, fortunately, was large enough to accommodate the cable in an unbroken length. foilhommerum bay, about six miles from valentia, was selected as the new irish terminus by the company. although the most anxious care was exercised in every detail, yet, when , miles had been laid, the cable parted in , feet of water, and although thrice it was grappled and brought toward the surface, thrice it slipped off the grappling hooks and escaped to the ocean floor. mr. field was obliged to return to england and face as best he might the men whose capital lay at the bottom of the sea--perchance as worthless as so much atlantic ooze. with heroic persistence he argued that all difficulties would yield to a renewed attack. there must be redoubled precautions and vigilance never for a moment relaxed. everything that deep-sea telegraphy has since accomplished was at that moment daylight clear to his prophetic view. never has there been a more signal example of the power of enthusiasm to stir cold-blooded men of business; never has there been a more striking illustration of how much science may depend for success upon the intelligence and the courage of capital. electricians might have gone on perfecting exquisite apparatus for ocean telegraphy, or indicated the weak points in the comparatively rude machinery which made and laid the cable, yet their exertions would have been wasted if men of wealth had not responded to mr. field's renewed appeal for help. thrice these men had invested largely, and thrice disaster had pursued their ventures; nevertheless they had faith surviving all misfortunes for a fourth attempt. in a new company was organized, for two objects: first, to recover the cable lost the previous year and complete it to the american shore; second, to lay another beside it in a parallel course. the _great eastern_ was again put in commission, and remodelled in accordance with the experience of her preceding voyage. this time the exterior wires of the cable were of galvanized iron, the better to resist corrosion. the paying-out machinery was reconstructed and greatly improved. on july , , the huge steamer began running out her cable twenty-five miles north of the line struck out during the expedition of ; she arrived without mishap in newfoundland on july , and electrical communication was re-established between america and europe. the steamer now returned to the spot where she had lost the cable a few months before; after eighteen days' search it was brought to the deck in good order. union was effected with the cable stowed in the tanks below, and the prow of the vessel was once more turned to newfoundland. on september th this second cable was safely landed at trinity bay. misfortunes now were at an end; the courage of mr. field knew victory at last; the highest honors of two continents were showered upon him. 'tis not the grapes of canaan that repay, but the high faith that failed not by the way. [illustration: fig. .--commercial cable, ] what at first was as much a daring adventure as a business enterprise has now taken its place as a task no more out of the common than building a steamship, or rearing a cantilever bridge. given its price, which will include too moderate a profit to betray any expectation of failure, and a responsible firm will contract to lay a cable across the pacific itself. in the atlantic lines the uniformly low temperature of the ocean floor (about ° c.), and the great pressure of the superincumbent sea, co-operate in effecting an enormous enhancement both in the insulation and in the carrying capacity of the wire. as an example of recent work in ocean telegraphy let us glance at the cable laid in , by the commercial cable company of new york. it unites cape canso, on the northeastern coast of nova scotia, to waterville, on the southwestern coast of ireland. the central portion of this cable much resembles that of its predecessor in . its exterior armour of steel wires is much more elaborate. the first part of fig. shows the details of manufacture: the central copper core is covered with gutta-percha, then with jute, upon which the steel wires are spirally wound, followed by a strong outer covering. for the greatest depths at sea, type _a_ is employed for a total length of , miles; the diameter of this part of the cable is seven-eighths of an inch. as the water lessens in depth the sheathing increases in size until the diameter of the cable becomes one and one-sixteenth inches for miles, as type _b_. the cable now undergoes a third enlargement, and then its fourth and last proportions are presented as it touches the shore, for a distance of one and three-quarter miles, where type _c_ has a diameter of two and one-half inches. the weights of material used in this cable are: copper wire, tons; gutta-percha, tons; jute yarn, tons; steel wire, , tons; compound and tar, , tons; total, , tons. the telegraph-ship _faraday_, specially designed for cable-laying, accomplished the work without mishap. electrical science owes much to the atlantic cables, in particular to the first of them. at the very beginning it banished the idea that electricity as it passes through metallic conductors has anything like its velocity through free space. it was soon found, as professor mendenhall says, "that it is no more correct to assign a definite velocity to electricity than to a river. as the rate of flow of a river is determined by the character of its bed, its gradient, and other circumstances, so the velocity of an electric current is found to depend on the conditions under which the flow takes place."[ ] mile for mile the original atlantic cable had twenty times the retarding effect of a good aerial line; the best recent cables reduce this figure by nearly one-half. in an extreme form, this slowing down reminds us of the obstruction of light as it enters the atmosphere of the earth, of the further impediment which the rays encounter if they pass from the air into the sea. in the main the causes which hinder a pulse committed to a cable are two: induction, and the electrostatic capacity of the wire, that is, the capacity of the wire to take up a charge of its own, just as if it were the metal of a leyden jar. let us first consider induction. as a current takes its way through the copper core it induces in its surroundings a second and opposing current. for this the remedy is one too costly to be applied. were a cable manufactured in a double line, as in the best telephonic circuits, induction, with its retarding and quenching effects, would be neutralized. here the steel wire armour which encircles the cable plays an unwelcome part. induction is always proportioned to the conductivity of the mass in which it appears; as steel is an excellent conductor, the armour of an ocean cable, close as it is to the copper core, has induced in it a current much stronger, and therefore more retarding, than if the steel wire were absent. a word now as to the second difficulty in working beneath the sea--that due to the absorbing power of the line itself. an atlantic cable, like any other extended conductor, is virtually a long, cylindrical leyden jar, the copper wire forming the inner coat, and its surroundings the outer coat. before a signal can be received at the distant terminus the wire must first be charged. the effect is somewhat like transmitting a signal through water which fills a rubber tube; first of all the tube is distended, and its compression, or secondary effect, really transmits the impulse. a remedy for this is a condenser formed of alternate sheets of tin-foil and mica, _c_, connected with the battery, _b_, so as to balance the electric charge of the cable wire (fig. ). in the first atlantic line an impulse demanded one-seventh of a second for its journey. this was reduced when mr. whitehouse made the capital discovery that the speed of a signal is increased threefold when the wire is alternately connected with the zinc and copper poles of the battery. sir william thomson ascertained that these successive pulses are most effective when of proportioned lengths. he accordingly devised an automatic transmitter which draws a duly perforated slip of paper under a metallic spring connected with the cable. to-day to letters are sent per minute instead of fifteen, as at first. [illustration: fig. .--condenser] in many ways a deep-sea cable exaggerates in an instructive manner the phenomena of telegraphy over long aerial lines. the two ends of a cable may be in regions of widely diverse electrical potential, or pressure, just as the readings of the barometer at these two places may differ much. if a copper wire were allowed to offer itself as a gateless conductor it would equalize these variations of potential with serious injury to itself. accordingly the rule is adopted of working the cable not directly, as if it were a land line, but indirectly through condensers. as the throb sent through such apparatus is but momentary, the cable is in no risk from the strong currents which would course through it if it were permitted to be an open channel. [illustration: fig. .--reflecting galvanometer l, lamp; n, moving spot of light reflected from mirror] a serious error in working the first cables was in supposing that they required strong currents as in land lines of considerable length. the very reverse is the fact. mr. charles bright, in _submarine telegraphs_, says: "mr. latimer clark had the conductor of the and lines joined together at the newfoundland end, thus forming an unbroken length of , miles in circuit. he then placed some sulphuric acid in a very small silver thimble, with a fragment of zinc weighing a grain or two. by this primitive agency he succeeded in conveying signals through twice the breadth of the atlantic ocean in little more than a second of time after making contact. the deflections were not of a dubious character, but full and strong, from which it was manifest than an even smaller battery would suffice to produce somewhat similar effects." [illustration: fig. .--siphon recorder] at first in operating the atlantic cable a mirror galvanometer was employed as a receiver. the principle of this receiver has often been illustrated by a mischievous boy as, with a slight and almost imperceptible motion of his hand, he has used a bit of looking-glass to dart a ray of reflected sunlight across a wide street or a large room. on the same plan, the extremely minute motion of a galvanometer, as it receives the successive pulsations of a message, is magnified by a weightless lever of light so that the words are easily read by an operator (fig. ). this beautiful invention comes from the hands of sir william thomson [now lord kelvin], who, more than any other electrician, has made ocean telegraphy an established success. [illustration: fig. .--siphon record. "arrived yesterday"] in another receiver, also of his design, the siphon recorder, he began by taking advantage of the fact, observed long before by bose, that a charge of electricity stimulates the flow of a liquid. in its original form the ink-well into which the siphon dipped was insulated and charged to a high voltage by an influence-machine; the ink, powerfully repelled, was spurted from the siphon point to a moving strip of paper beneath (fig. ). it was afterward found better to use a delicate mechanical shaker which throws out the ink in minute drops as the cable current gently sways the siphon back and forth (fig. ). minute as the current is which suffices for cable telegraphy, it is essential that the metallic circuit be not only unbroken, but unimpaired throughout. no part of his duty has more severely taxed the resources of the electrician than to discover the breaks and leaks in his ocean cables. one of his methods is to pour electricity as it were, into a broken wire, much as if it were a narrow tube, and estimate the length of the wire (and consequently the distance from shore to the defect or break) by the quantity of current required to fill it. footnotes: [ ] henry m. field, "history of the atlantic telegraph." new york: scribner, . [ ] "a century of electricity." boston, houghton, mifflin & co., . bell's telephonic researches [from "bell's electric speaking telephones," by george b. prescott, copyright by d appleton & co., new york, ] in a lecture delivered before the society of telegraph engineers, in london, october , , prof. a. g. bell gave a history of his researches in telephony, together with the experiments that he was led to undertake in his endeavours to produce a practical system of multiple telegraphy, and to realize also the transmission of articulate speech. after the usual introduction, professor bell said in part: it is to-night my pleasure, as well as duty, to give you some account of the telephonic researches in which i have been so long engaged. many years ago my attention was directed to the mechanism of speech by my father, alexander melville bell, of edinburgh, who has made a life-long study of the subject. many of those present may recollect the invention by my father of a means of representing, in a wonderfully accurate manner, the positions of the vocal organs in forming sounds. together we carried on quite a number of experiments, seeking to discover the correct mechanism of english and foreign elements of speech, and i remember especially an investigation in which we were engaged concerning the musical relations of vowel sounds. when vocal sounds are whispered, each vowel seems to possess a particular pitch of its own, and by whispering certain vowels in succession a musical scale can be distinctly perceived. our aim was to determine the natural pitch of each vowel; but unexpected difficulties made their appearance, for many of the vowels seemed to possess a double pitch--one due, probably, to the resonance of the air in the mouth, and the other to the resonance of the air contained in the cavity behind the tongue, comprehending the pharynx and larynx. i hit upon an expedient for determining the pitch, which, at that time, i thought to be original with myself. it consisted in vibrating a tuning fork in front of the mouth while the positions of the vocal organs for the various vowels were silently taken. it was found that each vowel position caused the reinforcement of some particular fork or forks. i wrote an account of these researches to mr. alex. j. ellis, of london. in reply, he informed me that the experiments related had already been performed by helmholtz, and in a much more perfect manner than i had done. indeed, he said that helmholtz had not only analyzed the vowel sounds into their constituent musical elements, but had actually performed the synthesis of them. he had succeeded in producing, artificially, certain of the vowel sounds by causing tuning forks of different pitch to vibrate simultaneously by means of an electric current. mr. ellis was kind enough to grant me an interview for the purpose of explaining the apparatus employed by helmholtz in producing these extraordinary effects, and i spent the greater part of a delightful day with him in investigating the subject. at that time, however, i was too slightly acquainted with the laws of electricity fully to understand the explanations given; but the interview had the effect of arousing my interest in the subjects of sound and electricity, and i did not rest until i had obtained possession of a copy of helmholtz's great work "the theory of tone," and had attempted, in a crude and imperfect manner, it is true, to reproduce his results. while reflecting upon the possibilities of the production of sound by electrical means, it struck me that the principle of vibrating a tuning fork by the intermittent attraction of an electro-magnet might be applied to the electrical production of music. i imagined to myself a series of tuning forks of different pitches, arranged to vibrate automatically in the manner shown by helmholtz--each fork interrupting, at every vibration, a voltaic current--and the thought occurred, why should not the depression of a key like that of a piano direct the interrupted current from any one of these forks, through a telegraph wire, to a series of electro-magnets operating the strings of a piano or other musical instrument, in which case a person might play the tuning fork piano in one place and the music be audible from the electro-magnetic piano in a distant city. the more i reflected upon this arrangement the more feasible did it seem to me; indeed, i saw no reason why the depression of a number of keys at the tuning fork end of the circuit should not be followed by the audible production of a full chord from the piano in the distant city, each tuning fork affecting at the receiving end that string of the piano with which it was in unison. at this time the interest which i felt in electricity led me to study the various systems of telegraphy in use in this country and in america. i was much struck with the simplicity of the morse alphabet, and with the fact that it could be read by sound. instead of having the dots and dashes recorded on paper, the operators were in the habit of observing the duration of the click of the instruments, and in this way were enabled to distinguish by ear the various signals. it struck me that in a similar manner the duration of a musical note might be made to represent the dot or dash of the telegraph code, so that a person might operate one of the keys of the tuning fork piano referred to above, and the duration of the sound proceeding from the corresponding string of the distant piano be observed by an operator stationed there. it seemed to me that in this way a number of distinct telegraph messages might be sent simultaneously from the tuning fork piano to the other end of the circuit by operators, each manipulating a different key of the instrument. these messages would be read by operators stationed at the distant piano, each receiving operator listening for signals for a certain definite pitch, and ignoring all others. in this way could be accomplished the simultaneous transmission of a number of telegraphic messages along a single wire, the number being limited only by the delicacy of the listener's ear. the idea of increasing the carrying power of a telegraph wire in this way took complete possession of my mind, and it was this practical end that i had in view when i commenced my researches in electric telephony. [illustration: fig. ] in the progress of science it is universally found that complexity leads to simplicity, and in narrating the history of scientific research it is often advisable to begin at the end. in glancing back over my own researches, i find it necessary to designate, by distinct names, a variety of electrical currents by means of which sounds can be produced, and i shall direct your attention to several distinct species of what may be termed telephonic currents of electricity. in order that the peculiarities of these currents may be clearly understood, i shall project upon the screen a graphical illustration of the different varieties. the graphical method of representing electrical currents shown in fig. is the best means i have been able to devise of studying, in an accurate manner, the effects produced by various forms of telephonic apparatus, and it has led me to the conception of that peculiar species of telephonic current, here designated as _undulatory_, which has rendered feasible the artificial production of articulate speech by electrical means. a horizontal line (_g g'_) is taken as the zero of current, and impulses of positive electricity are represented above the zero line, and negative impulses below it, or _vice versa_. the vertical thickness of any electrical impulse (_b_ or _d_), measured from the zero line, indicates the intensity of the electrical current at the point observed; and the horizontal extension of the electric line (_b_ or _d_) indicates the duration of the impulse. nine varieties of telephonic currents may be distinguished, but it will only be necessary to show you six of these. the three primary varieties designated as intermittent, pulsatory and undulatory, are represented in lines , and . sub-varieties of these can be distinguished as direct or reversed currents, according as the electrical impulses are all of one kind or are alternately positive and negative. direct currents may still further be distinguished as positive or negative, according as the impulses are of one kind or of the other. an intermittent current is characterized by the alternate presence and absence of electricity upon the circuit. a pulsatory current results from sudden or instantaneous changes in the intensity of a continuous current; and an undulatory current is a current of electricity, the intensity of which varies in a manner proportional to the velocity of the motion of a particle of air during the production of a sound: thus the curve representing graphically the undulatory current for a simple musical note is the curve expressive of a simple pendulous vibration--that is, a sinusoidal curve. and here i may remark, that, although the conception of the undulatory current of electricity is entirely original with myself, methods of producing sound by means of intermittent and pulsatory currents have long been known. for instance, it was long since discovered that an electro-magnet gives forth a decided sound when it is suddenly magnetized or demagnetized. when the circuit upon which it is placed is rapidly made and broken, a succession of explosive noises proceeds from the magnet. these sounds produce upon the ear the effect of a musical note when the current is interrupted a sufficient number of times per second.... [illustration: fig. ] for several years my attention was almost exclusively directed to the production of an instrument for making and breaking a voltaic circuit with extreme rapidity, to take the place of the transmitting tuning fork used in helmholtz's researches. without going into details, i shall merely say that the great defects of this plan of multiple telegraphy were found to consist, first, in the fact that the receiving operators were required to possess a good musical ear in order to discriminate the signals; and secondly, that the signals could only pass in one direction along the line (so that two wires would be necessary in order to complete communication in both directions). the first objection was got over by employing the device which i term a "vibratory circuit breaker," whereby musical signals can be automatically recorded.... i have formerly stated that helmholtz was enabled to produce vowel sounds artificially by combining musical tones of different pitches and intensities. his apparatus is shown in fig. . tuning forks of different pitch are placed between the poles of electro-magnets (_a _, _a _, &c.), and are kept in continuous vibration by the action of an intermittent current from the fork _b_. resonators, , , , etc., are arranged so as to reinforce the sounds in a greater or less degree, according as the exterior orifices are enlarged or contracted. [illustration: fig. ] thus it will be seen that upon helmholtz's plan the tuning forks themselves produce tones of uniform intensity, the loudness being varied by an external reinforcement; but it struck me that the same results would be obtained, and in a much more perfect manner, by causing the tuning forks themselves to vibrate with different degrees of amplitude. i therefore devised the apparatus shown in fig. , which was my first form of articulating telephone. in this figure a harp of steel rods is employed, attached to the poles of a permanent magnet, n. s. when any one of the rods is thrown into vibration an undulatory current is produced in the coils of the electro-magnet e, and the electro-magnet e' attracts the rods of the harp h' with a varying force, throwing into vibration that rod which is in unison with that vibrating at the other end of the circuit. not only so, but the amplitude of vibration in the one will determine the amplitude of vibration in the other, for the intensity of the induced current is determined by the amplitude of the inducing vibration, and the amplitude of the vibration at the receiving end depends upon the intensity of the attractive impulses. when we sing into a piano, certain of the strings of the instrument are set in vibration sympathetically by the action of the voice with different degrees of amplitude, and a sound, which is an approximation to the vowel uttered, is produced from the piano. theory shows that, had the piano a very much larger number of strings to the octave, the vowel sounds would be perfectly reproduced. my idea of the action of the apparatus, shown in fig. , was this: utter a sound in the neighbourhood of the harp h, and certain of the rods would be thrown into vibration with different amplitudes. at the other end of the circuit the corresponding rods of the harp h would vibrate with their proper relations of force, and the _timbre_ [characteristic quality] of the sound would be reproduced. the expense of constructing such an apparatus as that shown in figure deterred me from making the attempt, and i sought to simplify the apparatus before venturing to have it made. [illustration: fig. ] [illustration: fig. ] [illustration: fig. ] i have before alluded to the invention by my father of a system of physiological symbols for representing the action of the vocal organs, and i had been invited by the boston board of education to conduct a series of experiments with the system in the boston school for the deaf and dumb. it is well known that deaf mutes are dumb merely because they are deaf, and that there is no defect in their vocal organs to incapacitate them from utterance. hence it was thought that my father's system of pictorial symbols, popularly known as visible speech, might prove a means whereby we could teach the deaf and dumb to use their vocal organs and to speak. the great success of these experiments urged upon me the advisability of devising method of exhibiting the vibrations of sound optically, for use in teaching the deaf and dumb. for some time i carried on experiments with the manometric capsule of köenig and with the phonautograph of léon scott. the scientific apparatus in the institute of technology in boston was freely placed at my disposal for these experiments, and it happened that at that time a student of the institute of technology, mr. maurey, had invented an improvement upon the phonautograph. he had succeeded in vibrating by the voice a stylus of wood about a foot in length, which was attached to the membrane of the phonautograph, and in this way he had been enabled to obtain enlarged tracings upon a plane surface of smoked glass. with this apparatus i succeeded in producing very beautiful tracings of the vibrations of the air for vowel sounds. some of these tracings are shown in fig. . i was much struck with this improved form of apparatus, and it occurred to me that there was a remarkable likeness between the manner in which this piece of wood was vibrated by the membrane of the phonautograph and the manner in which the _ossiculo_ [small bones] of the human ear were moved by the tympanic membrane. i determined therefore, to construct a phonautograph modelled still more closely upon the mechanism of the human ear, and for this purpose i sought the assistance of a distinguished aurist in boston, dr. clarence j. blake. he suggested the use of the human ear itself as a phonautograph, instead of making an artificial imitation of it. the idea was novel and struck me accordingly, and i requested my friend to prepare a specimen for me, which he did. the apparatus, as finally constructed, is shown in fig. . the _stapes_ [inmost of the three auditory ossicles] was removed and a pointed piece of hay about an inch in length was attached to the end of the incus [the middle of the three auditory ossicles]. upon moistening the membrana tympani [membrane of the ear drum] and the ossiculæ with a mixture of glycerine and water the necessary mobility of the parts was obtained, and upon singing into the external artificial ear the piece of hay was thrown into vibration, and tracings were obtained upon a plane surface of smoked glass passed rapidly underneath. while engaged in these experiments i was struck with the remarkable disproportion in weight between the membrane and the bones that were vibrated by it. it occurred to me that if a membrane as thin as tissue paper could control the vibration of bones that were, compared to it, of immense size and weight, why should not a larger and thicker membrane be able to vibrate a piece of iron in front of an electro-magnet, in which case the complication of steel rods shown in my first form of telephone, fig. , could be done away with, and a simple piece of iron attached to a membrane be placed at either end of the telegraphic circuit. figure shows the form of apparatus that i was then employing for producing undulatory currents of electricity for the purpose of multiple telegraphy. a steel reed, a, was clamped firmly by one extremity to the uncovered leg _h_ of an electro-magnet e, and the free end of the reed projected above the covered leg. when the reed a was vibrated in any mechanical way the battery current was thrown into waves, and electrical undulations traversed the circuit b e w e', throwing into vibration the corresponding reed a' at the other end of the circuit. i immediately proceeded to put my new idea to the test of practical experiment, and for this purpose i attached the reed a (fig. ) loosely by one extremity to the uncovered pole _h_ of the magnet, and fastened the other extremity to the centre of a stretched membrane of goldbeaters' skin _n_. i presumed that upon speaking in the neighbourhood of the membrane _n_ it would be thrown into vibration and cause the steel reed a to move in a similar manner, occasioning undulations in the electrical current that would correspond to the changes in the density of the air during the production of the sound; and i further thought that the change of the density of the current at the receiving end would cause the magnet there to attract the reed a' in such a manner that it should copy the motion of the reed a, in which case its movements would occasion a sound from the membrane _n'_ similar in _timbre_ to that which had occasioned the original vibration. [illustration: fig. ] [illustration: fig. ] the results, however, were unsatisfactory and discouraging. my friend, mr. thomas a. watson, who assisted me in this first experiment, declared that he heard a faint sound proceed from the telephone at his end of the circuit, but i was unable to verify his assertion. after many experiments, attended by the same only partially successful results, i determined to reduce the size and weight of the spring as much as possible. for this purpose i glued a piece of clock spring about the size and shape of my thumb nail, firmly to the centre of the diaphragm, and had a similar instrument at the other end (fig. ); we were then enabled to obtain distinctly audible effects. i remember an experiment made with this telephone, which at the time gave me great satisfaction and delight. one of the telephones was placed in my lecture room in the boston university, and the other in the basement of the adjoining building. one of my students repaired to the distant telephone to observe the effects of articulate speech, while i uttered the sentence, "do you understand what i say?" into the telephone placed in the lecture hall. to my delight an answer was returned through the instrument itself, articulate sounds proceeded from the steel spring attached to the membrane, and i heard the sentence, "yes, i understand you perfectly." it is a mistake, however, to suppose that the articulation was by any means perfect, and expectancy no doubt had a great deal to do with my recognition of the sentence; still, the articulation was there, and i recognized the fact that the indistinctness was entirely due to the imperfection of the instrument. i will not trouble you by detailing the various stages through which the apparatus passed, but shall merely say that after a time i produced the form of instrument shown in fig. , which served very well as a receiving telephone. in this condition my invention was, in , exhibited at the centennial exhibition in philadelphia. the telephone shown in fig. was used as a transmitting instrument, and that in fig. as a receiver, so that vocal communication was only established in one direction.... [illustration: fig. ] the articulation produced from the instrument shown in fig. was remarkably distinct, but its great defect consisted in the fact that it could not be used as a transmitting instrument, and thus two telephones were required at each station, one for transmitting and one for receiving spoken messages. [illustration: fig. ] it was determined to vary the construction of the telephone shown in fig. , and i sought, by changing the size and tension of the membrane, the diameter and thickness of the steel spring, the size and power of the magnet, and the coils of insulated wire around their poles, to discover empirically the exact effect of each element of the combination, and thus to deduce a more perfect form of apparatus. it was found that a marked increase in the loudness of the sounds resulted from shortening the length of the coils of wire, and by enlarging the iron diaphragm which was glued to the membrane. in the latter case, also, the distinctness of the articulation was improved. finally, the membrane of goldbeaters' skin was discarded entirely, and a simple iron plate was used instead, and at once intelligible articulation was obtained. the new form of instrument is that shown in fig. , and, as had been long anticipated, it was proved that the only use of the battery was to magnetize the iron core, for the effects were equally audible when the battery was omitted and a rod of magnetized steel substituted for the iron core of the magnet. [illustration: fig. ] it was my original intention, as shown in fig. , and it was always claimed by me, that the final form of telephone would be operated by permanent magnets in place of batteries, and numerous experiments had been carried on by mr. watson and myself privately for the purpose of producing this effect. at the time the instruments were first exhibited in public the results obtained with permanent magnets were not nearly so striking as when a voltaic battery was employed, wherefore we thought it best to exhibit only the latter form of instrument. the interest excited by the first published accounts of the operation of the telephone led many persons to investigate the subject, and i doubt not that numbers of experimenters have independently discovered that permanent magnets might be employed instead of voltaic batteries. indeed, one gentleman, professor dolbear, of tufts college, not only claims to have discovered the magneto-electric telephone, but, i understand, charges me with having obtained the idea from him through the medium of a mutual friend. a still more powerful form of apparatus was constructed by using a powerful compound horseshoe magnet in place of the straight rod which had been previously used (see fig. ). indeed, the sounds produced by means of this instrument were of sufficient loudness to be faintly audible to a large audience, and in this condition the instrument was exhibited in the essex institute, in salem, massachusetts, on the th of february, , on which occasion a short speech shouted into a similar telephone in boston sixteen miles away, was heard by the audience in salem. the tones of the speaker's voice were distinctly audible to an audience of six hundred people, but the articulation was only distinct at a distance of about six feet. on the same occasion, also, a report of the lecture was transmitted by word of mouth from salem to boston, and published in the papers the next morning. from the form of telephone shown in fig. to the present form of the instrument (fig. ) is but a step. it is, in fact, the arrangement of fig. in a portable form, the magnet f. h. being placed inside the handle and a more convenient form of mouthpiece provided.... it was always my belief that a certain ratio would be found between the several parts of a telephone, and that the size of the instrument was immaterial; but professor peirce was the first to demonstrate the extreme smallness of the magnets which might be employed. and here, in order to show the parallel lines in which we were working, i may mention the fact that two or three days after i had constructed a telephone of the portable form (fig. ), containing the magnet inside the handle, dr. channing was kind enough to send me a pair of telephones of a similar pattern, which had been invented by experimenters at providence. the convenient form of the mouthpiece shown in fig. , now adopted by me, was invented solely by my friend, professor peirce. i must also express my obligations to my friend and associate, mr. thomas a. watson, of salem, massachusetts, who has for two years past given me his personal assistance in carrying on my researches. in pursuing my investigations i have ever had one end in view--the practical improvement of electric telegraphy--but i have come across many facts which, while having no direct bearing upon the subject of telegraphy, may yet possess an interest for you. for instance, i have found that a musical tone proceeds from a piece of plumbago or retort carbon when an intermittent current of electricity is passed through it, and i have observed the most curious audible effects produced by the passage of reversed intermittent currents through the human body. a breaker was placed in circuit with the primary wires of an induction coil, and the fine wires were connected with two strips of brass. one of these strips was held closely against the ear, and a loud sound proceeded from it whenever the other slip was touched with the other hand. the strips of brass were next held one in each hand. the induced currents occasioned a muscular tremor in the fingers. upon placing my forefinger to my ear a loud crackling noise was audible, seemingly proceeding from the finger itself. a friend who was present placed my finger to his ear, but heard nothing. i requested him to hold the strips himself. he was then distinctly conscious of a noise (which i was unable to perceive) proceeding from his finger. in this case a portion of the induced current passed through the head of the observer when he placed his ear against his own finger, and it is possible that the sound was occasioned by a vibration of the surfaces of the ear and finger in contact. when two persons receive a shock from a ruhmkorff's coil by clasping hands, each taking hold of one wire of the coil with the free hand, a sound proceeds from the clasped hands. the effect is not produced when the hands are moist. when either of the two touches the body of the other a loud sound comes from the parts in contact. when the arm of one is placed against the arm of the other, the noise produced can be heard at a distance of several feet. in all these cases a slight shock is experienced so long as the contact is preserved. the introduction of a piece of paper between the parts in contact does not materially interfere with the production of the sounds, but the unpleasant effects of the shock are avoided. [illustration: fig. ] when an intermittent current from a ruhmkorff's coil is passed through the arms a musical note can be perceived when the ear is closely applied to the arm of the person experimented upon. the sound seems to proceed from the muscles of the fore-arm and from the biceps muscle. mr. elisha gray has also produced audible effects by the passage of electricity through the human body. an extremely loud musical note is occasioned by the spark of a ruhmkorff's coil when the primary circuit is made and broken with sufficient rapidity. when two breakers of different pitch are caused simultaneously to open and close the primary circuit a double tone proceeds from the spark. a curious discovery, which may be of interest to you, has been made by professor blake. he constructed a telephone in which a rod of soft iron, about six feet in length, was used instead of a permanent magnet. a friend sang a continuous musical tone into the mouthpiece of a telephone, like that shown in fig. , which was connected with the soft iron instrument alluded to above. it was found that the loudness of the sound produced in this telephone varied with the direction in which the iron rod was held, and that the maximum effect was produced when the rod was in the position of the dipping needle. this curious discovery of professor blake has been verified by myself. when a telephone is placed in circuit with a telegraph line the telephone is found seemingly to emit sounds on its own account. the most extraordinary noises are often produced, the causes of which are at present very obscure. one class of sounds is produced by the inductive influence of neighbouring wires and by leakage from them, the signals of the morse alphabet passing over neighbouring wires being audible in the telephone, and another class can be traced to earth currents upon the wire, a curious modification of this sound revealing the presence of defective joints in the wire. professor blake informs me that he has been able to use the railroad track for conversational purposes in place of a telegraph wire, and he further states that when only one telephone was connected with the track the sounds of morse operating were distinctly audible in the telephone, although the nearest telegraph wires were at least fifty feet distant. professor peirce has observed the most singular sounds produced from a telephone in connection with a telegraph wire during the aurora borealis, and i have just heard of a curious phenomenon lately observed by dr. channing. in the city of providence, rhode island, there is an over-house wire about one mile in extent with a telephone at either end. on one occasion the sound of music and singing was faintly audible in one of the telephones. it seemed as if some one were practising vocal music with a pianoforte accompaniment. the natural supposition was that experiments were being made with the telephone at the other end of the circuit, but upon inquiry this proved not to have been the case. attention having thus been directed to the phenomenon, a watch was kept upon the instruments, and upon a subsequent occasion the same fact was observed at both ends of the line by dr. channing and his friends. it was proved that the sounds continued for about two hours, and usually commenced about the same time. a searching examination of the line disclosed nothing abnormal in its condition, and i am unable to give you any explanation of this curious phenomenon. dr. channing has, however, addressed a letter upon the subject to the editor of one of the providence papers, giving the names of such songs as were recognized, and full details of the observations, in the hope that publicity may lead to the discovery of the performer, and thus afford a solution of the mystery. my friend, mr. frederick a. gower, communicated to me a curious observation made by him regarding the slight earth connection required to establish a circuit for the telephone, and together we carried on a series of experiments with rather startling results. we took a couple of telephones and an insulated wire about yards in length into a garden, and were enabled to carry on conversation with the greatest ease when we held in our hands what should have been the earth wire, so that the connection with the ground was formed at either end through our bodies, our feet being clothed with cotton socks and leather boots. the day was fine, and the grass upon which we stood was seemingly perfectly dry. upon standing upon a gravel walk the vocal sounds, though much diminished, were still perfectly intelligible, and the same result occurred when standing upon a brick wall one foot in height, but no sound was audible when one of us stood upon a block of freestone. one experiment which we made is so very interesting that i must speak of it in detail. mr. gower made earth connection at his end of the line by standing upon a grass plot, whilst at the other end of the line i stood upon a wooden board. i requested mr. gower to sing a continuous musical note, and to my surprise the sound was very distinctly audible from the telephone in my hand. upon examining my feet i discovered that a single blade of grass was bent over the edge of the board, and that my foot touched it. the removal of this blade of grass was followed by the cessation of the sound from the telephone, and i found that the moment i touched with the toe of my boot a blade of grass or the petal of a daisy the sound was again audible. the question will naturally arise, through what length of wire can the telephone be used? in reply to this i may say that the maximum amount of resistance through which the undulatory current will pass, and yet retain sufficient force to produce an audible sound at the distant end, has yet to be determined; no difficulty has, however, been experienced in laboratory experiments in conversing through a resistance of , ohms, which has been the maximum at my disposal. on one occasion, not having a rheostat [for producing resistance] at hand, i passed the current through the bodies of sixteen persons, who stood hand in hand. the longest length of real telegraph line through which i have attempted to converse has been about miles. on this occasion no difficulty was experienced so long as parallel lines were not in operation. sunday was chosen as the day on which it was probable other circuits would be at rest. conversation was carried on between myself, in new york, and mr. thomas a. watson, in boston, until the opening of business upon the other wires. when this happened the vocal sounds were very much diminished, but still audible. it seemed, indeed, like talking through a storm. conversation, though possible, could be carried on with difficulty, owing to the distracting nature of the interfering currents. i am informed by my friend mr. preece that conversation has been successfully carried on through a submarine cable, sixty miles in length, extending from dartmouth to the island of guernsey, by means of hand telephones. photographing the unseen: the roentgen ray h. j. w. dam [by permission from _mcclure's magazine_, april, , copyright by s. s. mcclure, limited.] in all the history of scientific discovery there has never been, perhaps, so general, rapid, and dramatic an effect wrought on the scientific centres of europe as has followed, in the past four weeks, upon an announcement made to the würzburg physico-medical society, at their december [ ] meeting, by professor william konrad röntgen, professor of physics at the royal university of würzburg. the first news which reached london was by telegraph from vienna to the effect that a professor röntgen, until then the possessor of only a local fame in the town mentioned, had discovered a new kind of light, which penetrated and photographed through everything. this news was received with a mild interest, some amusement, and much incredulity; and a week passed. then, by mail and telegraph, came daily clear indications of the stir which the discovery was making in all the great line of universities between vienna and berlin. then röntgen's own report arrived, so cool, so business-like, and so truly scientific in character, that it left no doubt either of the truth or of the great importance of the preceding reports. to-day, four weeks after the announcement, röntgen's name is apparently in every scientific publication issued this week in europe; and accounts of his experiments, of the experiments of others following his method, and of theories as to the strange new force which he has been the first to observe, fill pages of every scientific journal that comes to hand. and before the necessary time elapses for this article to attain publication in america, it is in all ways probable that the laboratories and lecture-rooms of the united states will also be giving full evidence of this contagious arousal of interest over a discovery so strange that its importance cannot yet be measured, its utility be even prophesied, or its ultimate effect upon long established scientific beliefs be even vaguely foretold. the röntgen rays are certain invisible rays resembling, in many respects, rays of light, which are set free when a high-pressure electric current is discharged through a vacuum tube. a vacuum tube is a glass tube from which all the air, down to one-millionth of an atmosphere, has been exhausted after the insertion of a platinum wire in either end of the tube for connection with the two poles of a battery or induction coil. when the discharge is sent through the tube, there proceeds from the anode--that is, the wire which is connected with the positive pole of the battery--certain bands of light, varying in colour with the colour of the glass. but these are insignificant in comparison with the brilliant glow which shoots from the cathode, or negative wire. this glow excites brilliant phosphorescence in glass and many substances, and these "cathode rays," as they are called, were observed and studied by hertz; and more deeply by his assistant, professor lenard, lenard having, in , reported that the cathode rays would penetrate thin films of aluminum, wood, and other substances, and produce photographic results beyond. it was left, however, for professor röntgen to discover that during the discharge quite other rays are set free, which differ greatly from those described by lenard as cathode rays. the most marked difference between the two is the fact that röntgen rays are not deflected by a magnet, indicating a very essential difference, while their range and penetrative power are incomparably greater. in fact, all those qualities which have lent a sensational character to the discovery of röntgen's rays were mainly absent from those of lenard, to the end that, although röntgen has not been working in an entirely new field, he has by common accord been freely granted all the honors of a great discovery. exactly what kind of a force professor röntgen has discovered he does not know. as will be seen below, he declines to call it a new kind of light, or a new form of electricity. he has given it the name of the x rays. others speak of it as the röntgen rays. thus far its results only, and not its essence, are known. in the terminology of science it is generally called "a new mode of motion," or, in other words, a new force. as to whether it is or not actually a force new to science, or one of the known forces masquerading under strange conditions, weighty authorities are already arguing. more than one eminent scientist has already affected to see in it a key to the great mystery of the law of gravity. all who have expressed themselves in print have admitted, with more or less frankness, that, in view of röntgen's discovery, science must forthwith revise, possibly to a revolutionary degree, the long accepted theories concerning the phenomena of light and sound. that the x rays, in their mode of action, combine a strange resemblance to both sound and light vibrations, and are destined to materially affect, if they do not greatly alter, our views of both phenomena, is already certain; and beyond this is the opening into a new and unknown field of physical knowledge, concerning which speculation is already eager, and experimental investigation already in hand, in london, paris, berlin, and, perhaps, to a greater or less extent, in every well-equipped physical laboratory in europe. this is the present scientific aspect of the discovery. but, unlike most epoch-making results from laboratories, this discovery is one which, to a very unusual degree, is within the grasp of the popular and non-technical imagination. among the other kinds of matter which these rays penetrate with ease is human flesh. that a new photography has suddenly arisen which can photograph the bones, and, before long, the organs of the human body; that a light has been found which can penetrate, so as to make a photographic record, through everything from a purse or a pocket to the walls of a room or a house, is news which cannot fail to startle everybody. that the eye of the physician or surgeon, long baffled by the skin, and vainly seeking to penetrate the unfortunate darkness of the human body, is now to be supplemented by a camera, making all the parts of the human body as visible, in a way, as the exterior, appears certainly to be a greater blessing to humanity than even the listerian antiseptic system of surgery; and its benefits must inevitably be greater than those conferred by lister, great as the latter have been. already, in the few weeks since röntgen's announcement, the results of surgical operations under the new system are growing voluminous. in berlin, not only new bone fractures are being immediately photographed, but joined fractures, as well, in order to examine the results of recent surgical work. in vienna, imbedded bullets are being photographed, instead of being probed for, and extracted with comparative ease. in london, a wounded sailor, completely paralyzed, whose injury was a mystery, has been saved by the photographing of an object imbedded in the spine, which, upon extraction, proved to be a small knife-blade. operations for malformations, hitherto obscure, but now clearly revealed by the new photography, are already becoming common, and are being reported from all directions. professor czermark of graz has photographed the living skull, denuded of flesh and hair, and has begun the adaptation of the new photography to brain study. the relation of the new rays to thought rays is being eagerly discussed in what may be called the non-exact circles and journals; and all that numerous group of inquirers into the occult, the believers in clairvoyance, spiritualism, telepathy, and kindred orders of alleged phenomena, are confident of finding in the new force long-sought facts in proof of their claims. professor neusser in vienna has photographed gallstones in the liver of one patient (the stone showing snow-white in the negative), and a stone in the bladder of another patient. his results so far induce him to announce that all the organs of the human body can, and will, shortly, be photographed. lannelongue of paris has exhibited to the academy of science photographs of bones showing inherited tuberculosis which had not otherwise revealed itself. berlin has already formed a society of forty for the immediate prosecution of researches into both the character of the new force and its physiological possibilities. in the next few weeks these strange announcements will be trebled or quadrupled, giving the best evidence from all quarters of the great future that awaits the röntgen rays, and the startling impetus to the universal search for knowledge that has come at the close of the nineteenth century from the modest little laboratory in the pleicher ring at würzburg. the physical institute, professor röntgen's particular domain, is a modest building of two stories and basement, the upper story constituting his private residence, and the remainder of the building being given over to lecture rooms, laboratories, and their attendant offices. at the door i was met by an old serving-man of the idolatrous order, whose pain was apparent when i asked for "professor" röntgen, and he gently corrected me with "herr doctor röntgen." as it was evident, however, that we referred to the same person, he conducted me along a wide, bare hall, running the length of the building, with blackboards and charts on the walls. at the end he showed me into a small room on the right. this contained a large table desk, and a small table by the window, covered by photographs, while the walls held rows of shelves laden with laboratory and other records. an open door led into a somewhat larger room, perhaps twenty feet by fifteen, and i found myself gazing into a laboratory which was the scene of the discovery--a laboratory which, though in all ways modest, is destined to be enduringly historical. there was a wide table shelf running along the farther side, in front of the two windows, which were high, and gave plenty of light. in the centre was a stove; on the left, a small cabinet whose shelves held the small objects which the professor had been using. there was a table in the left-hand corner; and another small table--the one on which living bones were first photographed--was near the stove, and a ruhmkorff coil was on the right. the lesson of the laboratory was eloquent. compared, for instance, with the elaborate, expensive, and complete apparatus of, say, the university of london, or of any of the great american universities, it was bare and unassuming to a degree. it mutely said that in the great march of science it is the genius of man, and not the perfection of appliances, that breaks new ground in the great territory of the unknown. it also caused one to wonder at and endeavour to imagine the great things which are to be done through elaborate appliances with the röntgen rays--a field in which the united states, with its foremost genius in invention, will very possibly, if not probably, take the lead--when the discoverer himself had done so much with so little. already, in a few weeks, a skilled london operator, mr. a. a. c. swinton, has reduced the necessary time of exposure for röntgen photographs from fifteen minutes to four. he used, however, a tesla oil coil, discharged by twelve half-gallon leyden jars, with an alternating current of twenty thousand volts' pressure. here were no oil coils, leyden jars, or specially elaborate and expensive machines. there were only a ruhmkorff coil and crookes (vacuum) tube and the man himself. professor röntgen entered hurriedly, something like an amiable gust of wind. he is a tall, slender, and loose-limbed man, whose whole appearance bespeaks enthusiasm and energy. he wore a dark blue sack suit, and his long, dark hair stood straight up from his forehead, as if he were permanently electrified by his own enthusiasm. his voice is full and deep, he speaks rapidly, and, altogether, he seems clearly a man who, once upon the track of a mystery which appealed to him, would pursue it with unremitting vigor. his eyes are kind, quick, and penetrating; and there is no doubt that he much prefers gazing at a crookes tube to beholding a visitor, visitors at present robbing him of much valued time. the meeting was by appointment, however, and his greeting was cordial and hearty. in addition to his own language he speaks french well and english scientifically, which is different from speaking it popularly. these three tongues being more or less within the equipment of his visitor, the conversation proceeded on an international or polyglot basis, so to speak, varying at necessity's demand. it transpired in the course of inquiry, that the professor is a married man and fifty years of age, though his eyes have the enthusiasm of twenty-five. he was born near zurich, and educated there, and completed his studies and took his degree at utrecht. he has been at würzburg about seven years, and had made no discoveries which he considered of great importance prior to the one under consideration. these details were given under good-natured protest, he failing to understand why his personality should interest the public. he declined to admire himself or his results in any degree, and laughed at the idea of being famous. the professor is too deeply interested in science to waste any time in thinking about himself. his emperor had feasted, flattered, and decorated him, and he was loyally grateful. it was evident, however, that fame and applause had small attractions for him, compared to the mysteries still hidden in the vacuum tubes of the other room. "now, then," said he, smiling, and with some impatience, when the preliminary questions at which he chafed were over, "you have come to see the invisible rays." "is the invisible visible?" "not to the eye; but its results are. come in here." [illustration: bones of a human foot photographed through the flesh from a photograph by a. a. c. swinton, victoria street, london. exposure, fifty-five seconds] he led the way to the other square room mentioned, and indicated the induction coil with which his researches were made, an ordinary ruhmkorff coil, with a spark of from four to six inches, charged by a current of twenty amperes. two wires led from the coil, through an open door, into a smaller room on the right. in this room was a small table carrying a crookes tube connected with the coil. the most striking object in the room, however, was a huge and mysterious tin box about seven feet high and four feet square. it stood on end, like a huge packing case, its side being perhaps five inches from the crookes tube. the professor explained the mystery of the tin box, to the effect that it was a device of his own for obtaining a portable dark-room. when he began his investigations he used the whole room, as was shown by the heavy blinds and curtains so arranged as to exclude the entrance of all interfering light from the windows. in the side of the tin box, at the point immediately against the tube, was a circular sheet of aluminum one millimetre in thickness, and perhaps eighteen inches in diameter, soldered to the surrounding tin. to study his rays the professor had only to turn on the current, enter the box, close the door, and in perfect darkness inspect only such light or light effects as he had a right to consider his own, hiding his light, in fact, not under the biblical bushel, but in a more commodious box. "step inside," said he, opening the door, which was on the side of the box farthest from the tube. i immediately did so, not altogether certain whether my skeleton was to be photographed for general inspection, or my secret thoughts held up to light on a glass plate. "you will find a sheet of barium paper on the shelf," he added, and then went away to the coil. the door was closed, and the interior of the box became black darkness. the first thing i found was a wooden stool, on which i resolved to sit. then i found the shelf on the side next the tube, and then the sheet of paper prepared with barium platinocyanide. i was thus being shown the first phenomenon which attracted the discoverer's attention and led to his discovery, namely, the passage of rays, themselves wholly invisible, whose presence was only indicated by the effect they produced on a piece of sensitized photographic paper. a moment later, the black darkness was penetrated by the rapid snapping sound of the high-pressure current in action, and i knew that the tube outside was glowing. i held the sheet vertically on the shelf, perhaps four inches from the plate. there was no change, however, and nothing was visible. "do you see anything?" he called. "no." "the tension is not high enough;" and he proceeded to increase the pressure by operating an apparatus of mercury in long vertical tubes acted upon automatically by a weight lever which stood near the coil. in a few moments the sound of the discharge again began, and then i made my first acquaintance with the röntgen rays. the moment the current passed, the paper began to glow. a yellowish green light spread all over its surface in clouds, waves and flashes. the yellow-green luminescence, all the stranger and stronger in the darkness, trembled, wavered, and floated over the paper, in rhythm with the snapping of the discharge. through the metal plate, the paper, myself, and the tin box, the invisible rays were flying, with an effect strange, interesting and uncanny. the metal plate seemed to offer no appreciable resistance to the flying force, and the light was as rich and full as if nothing lay between the paper and the tube. "put the book up," said the professor. i felt upon the shelf, in the darkness, a heavy book, two inches in thickness, and placed this against the plate. it made no difference. the rays flew through the metal and the book as if neither had been there, and the waves of light, rolling cloud-like over the paper, showed no change in brightness. it was a clear, material illustration of the ease with which paper and wood are penetrated. and then i laid book and paper down, and put my eyes against the rays. all was blackness, and i neither saw nor felt anything. the discharge was in full force, and the rays were flying through my head, and, for all i knew, through the side of the box behind me. but they were invisible and impalpable. they gave no sensation whatever. whatever the mysterious rays may be, they are not to be seen, and are to be judged only by their works. i was loath to leave this historical tin box, but time pressed. i thanked the professor, who was happy in the reality of his discovery and the music of his sparks. then i said: "where did you first photograph living bones?" "here," he said, leading the way into the room where the coil stood. he pointed to a table on which was another--the latter a small short-legged wooden one with more the shape and size of a wooden seat. it was two feet square and painted coal black. i viewed it with interest. i would have bought it, for the little table on which light was first sent through the human body will some day be a great historical curiosity; but it was not for sale. a photograph of it would have been a consolation, but for several reasons one was not to be had at present. however, the historical table was there, and was duly inspected. "how did you take the first hand photograph?" i asked. the professor went over to a shelf by the window, where lay a number of prepared glass plates, closely wrapped in black paper. he put a crookes tube underneath the table, a few inches from the under side of its top. then he laid his hand flat on the top of the table, and placed the glass plate loosely on his hand. "you ought to have your portrait painted in that attitude," i suggested. "no, that is nonsense," said he, smiling. "or be photographed." this suggestion was made with a deeply hidden purpose. the rays from the röntgen eyes instantly penetrated the deeply hidden purpose. "oh, no," said he; "i can't let you make pictures of me. i am too busy." clearly the professor was entirely too modest to gratify the wishes of the curious world. "now, professor," said i, "will you tell me the history of the discovery?" "there is no history," he said. "i have been for a long time interested in the problem of the cathode rays from a vacuum tube as studied by hertz and lenard. i had followed their and other researches with great interest, and determined, as soon as i had the time, to make some researches of my own. this time i found at the close of last october. i had been at work for some days when i discovered something new." "what was the date?" "the eighth of november." "and what was the discovery?" "i was working with a crookes tube covered by a shield of black cardboard. a piece of barium platinocyanide paper lay on the bench there. i had been passing a current through the tube, and i noticed a peculiar black line across the paper." "what of that?" "the effect was one which could only be produced, in ordinary parlance, by the passage of light. no light could come from the tube, because the shield which covered it was impervious to any light known, even that of the electric arc." "and what did you think?" "i did not think; i investigated. i assumed that the effect must have come from the tube, since its character indicated that it could come from nowhere else. i tested it. in a few minutes there was no doubt about it. rays were coming from the tube which had a luminescent effect upon the paper. i tried it successfully at greater and greater distances, even at two metres. it seemed at first a new kind of invisible light. it was clearly something new, something unrecorded." "is it light?" "no." "is it electricity?" "not in any known form." "what is it?" "i don't know." and the discoverer of the x rays thus stated as calmly his ignorance of their essence as has everybody else who has written on the phenomena thus far. "having discovered the existence of a new kind of rays, i of course began to investigate what they would do." he took up a series of cabinet-sized photographs. "it soon appeared from tests that the rays had penetrative powers to a degree hitherto unknown. they penetrated paper, wood, and cloth with ease; and the thickness of the substance made no perceptible difference, within reasonable limits." he showed photographs of a box of laboratory weights of platinum, aluminum, and brass, they and the brass hinges all having been photographed from a closed box, without any indication of the box. also a photograph of a coil of fine wire, wound on a wooden spool, the wire having been photographed, and the wood omitted. "the rays," he continued, "passed through all the metals tested, with a facility varying, roughly speaking, with the density of the metal. these phenomena i have discussed carefully in my report to the würzburg society, and you will find all the technical results therein stated." he showed a photograph of a small sheet of zinc. this was composed of smaller plates soldered laterally with solders of different metallic proportions. the differing lines of shadow, caused by the difference in the solders, were visible evidence that a new means of detecting flaws and chemical variations in metals had been found. a photograph of a compass showed the needle and dial taken through the closed brass cover. the markings of the dial were in red metallic paint, and thus interfered with the rays, and were reproduced. "since the rays had this great penetrative power, it seemed natural that they should penetrate flesh, and so it proved in photographing the hand, as i showed you." a detailed discussion of the characteristics of his rays the professor considered unprofitable and unnecessary. he believes, though, that these mysterious radiations are not light, because their behaviour is essentially different from that of light rays, even those light rays which are themselves invisible. the röntgen rays cannot be reflected by reflecting surfaces, concentrated by lenses, or refracted or diffracted. they produce photographic action on a sensitive film, but their action is weak as yet, and herein lies the first important field of their development. the professor's exposures were comparatively long--an average of fifteen minutes in easily penetrable media, and half an hour or more in photographing the bones of the hand. concerning vacuum tubes, he said that he preferred the hittorf, because it had the most perfect vacuum, the highest degree of air exhaustion being the consummation most desirable. in answer to a question, "what of the future?" he said: "i am not a prophet, and i am opposed to prophesying. i am pursuing my investigations, and as fast as my results are verified i shall make them public." "do you think the rays can be so modified as to photograph the organs of the human body?" in answer he took up the photograph of the box of weights. "here are already modifications," he said, indicating the various degrees of shadow produced by the aluminum, platinum, and brass weights, the brass hinges, and even the metallic stamped lettering on the cover of the box, which was faintly perceptible. "but professor neusser has already announced that the photographing of the various organs is possible." "we shall see what we shall see," he said. "we have the start now; the development will follow in time." "you know the apparatus for introducing the electric light into the stomach?" "yes." "do you think that this electric light will become a vacuum tube for photographing, from the stomach, any part of the abdomen or thorax?" the idea of swallowing a crookes tube, and sending a high frequency current down into one's stomach, seemed to him exceedingly funny. "when i have done it, i will tell you," he said, smiling, resolute in abiding by results. "there is much to do, and i am busy, very busy," he said in conclusion. he extended his hand in farewell, his eyes already wandering toward his work in the inside room. and his visitor promptly left him; the words, "i am busy," said in all sincerity, seeming to describe in a single phrase the essence of his character and the watchword of a very unusual man. returning by way of berlin, i called upon herr spies of the urania, whose photographs after the röntgen method were the first made public, and have been the best seen thus far. in speaking of the discovery he said: "i applied it, as soon as the penetration of flesh was apparent, to the photograph of a man's hand. something in it had pained him for years, and the photograph at once exhibited a small foreign object, as you can see;" and he exhibited a copy of the photograph in question. "the speck there is a small piece of glass, which was immediately extracted, and which, in all probability, would have otherwise remained in the man's hand to the end of his days." all of which indicates that the needle which has pursued its travels in so many persons, through so many years, will be suppressed by the camera. "my next object is to photograph the bones of the entire leg," continued herr spies. "i anticipate no difficulty, though it requires some thought in manipulation." it will be seen that the röntgen rays and their marvellous practical possibilities are still in their infancy. the first successful modification of the action of the rays so that the varying densities of bodily organs will enable them to be photographed will bring all such morbid growths as tumours and cancers into the photographic field, to say nothing of vital organs which may be abnormally developed or degenerate. how much this means to medical and surgical practice it requires little imagination to conceive. diagnosis, long a painfully uncertain science, has received an unexpected and wonderful assistant; and how greatly the world will benefit thereby, how much pain will be saved, only the future can determine. in science a new door has been opened where none was known to exist, and a side-light on phenomena has appeared, of which the results may prove as penetrating and astonishing as the röntgen rays themselves. the most agreeable feature of the discovery is the opportunity it gives for other hands to help; and the work of these hands will add many new words to the dictionaries, many new facts to science, and, in the years long ahead of us, fill many more volumes than there are paragraphs in this brief and imperfect account. the wireless telegraph george iles [from "flame, electricity and the camera," copyright by doubleday, page & co., new york.] in a series of experiments interesting enough but barren of utility, the water of a canal, river, or bay has often served as a conductor for the telegraph. among the electricians who have thus impressed water into their service was professor morse. in he sent a few signals across the channel from castle garden, new york, to governor's island, a distance of a mile. with much better results, he sent messages, later in the same year, from one side of the canal at washington to the other, a distance of eighty feet, employing large copper plates at each terminal. the enormous current required to overcome the resistance of water has barred this method from practical adoption. we pass, therefore, to electrical communication as effected by induction--the influence which one conductor exerts on another through an intervening insulator. at the outset we shall do well to bear in mind that magnetic phenomena, which are so closely akin to electrical, are always inductive. to observe a common example of magnetic induction, we have only to move a horseshoe magnet in the vicinity of a compass needle, which will instantly sway about as if blown hither and thither by a sharp draught of air. this action takes place if a slate, a pane of glass, or a shingle is interposed between the needle and its perturber. there is no known insulator for magnetism, and an induction of this kind exerts itself perceptibly for many yards when large masses of iron are polarised, so that the derangement of compasses at sea from moving iron objects aboard ship, or from ferric ores underlying a sea-coast, is a constant peril to the mariner. electrical conductors behave much like magnetic masses. a current conveyed by a conductor induces a counter-current in all surrounding bodies, and in a degree proportioned to their conductive power. this effect is, of course, greatest upon the bodies nearest at hand, and we have already remarked its serious retarding effect in ocean telegraphy. when the original current is of high intensity, it can induce a perceptible current in another wire at a distance of several miles. in henry remarked that electric waves had this quality, but in that early day of electrical interpretation the full significance of the fact eluded him. in the top room of his house he produced a spark an inch long, which induced currents in wires stretched in his cellar, through two thick floors and two rooms which came between. induction of this sort causes the annoyance, familiar in single telephonic circuits, of being obliged to overhear other subscribers, whose wires are often far away from our own. the first practical use of induced currents in telegraphy was when mr. edison, in , enabled the trains on a line of the staten island railroad to be kept in constant communication with a telegraphic wire, suspended in the ordinary way beside the track. the roof of a car was of insulated metal, and every tap of an operator's key within the walls electrified the roof just long enough to induce a brief pulse through the telegraphic circuit. in sending a message to the car this wire was, moment by moment, electrified, inducing a response first in the car roof, and next in the "sounder" beneath it. this remarkable apparatus, afterward used on the lehigh valley railroad, was discontinued from lack of commercial support, although it would seem to be advantageous to maintain such a service on other than commercial grounds. in case of chance obstructions on the track, or other peril, to be able to communicate at any moment with a train as it speeds along might mean safety instead of disaster. the chief item in the cost of this system is the large outlay for a special telegraphic wire. the next electrician to employ induced currents in telegraphy was mr. (now sir) william h. preece, the engineer then at the head of the british telegraph system. let one example of his work be cited. in a cable was laid between lavernock, near cardiff, on the bristol channel, and flat holme, an island three and a third miles off. as the channel at this point is a much-frequented route and anchor ground, the cable was broken again and again. as a substitute for it mr. preece, in , strung wires along the opposite shores, and found that an electric pulse sent through one wire instantly made itself heard in a telephone connected with the other. it would seem that in this etheric form of telegraphy the two opposite lines of wire must be each as long as the distance which separates them; therefore, to communicate across the english channel from dover to calais would require a line along each coast at least twenty miles in length. where such lines exist for ordinary telegraphy, they might easily lend themselves to the preece system of signalling in case a submarine cable were to part. marconi, adopting electrostatic instead of electro-magnetic waves, has won striking results. let us note the chief of his forerunners, as they prepared the way for him. in maxwell observed that electricity and light have the same velocity, , miles a second, and he formulated the theory that electricity propagates itself in waves which differ from those of light only in being longer. this was proved to be true by hertz, who in showed that where alternating currents of very high frequency were set up in an open circuit, the energy might be conveyed entirely away from the circuit into the surrounding space as electric waves. his detector was a nearly closed circle of wire, the ends being soldered to metal balls almost in contact. with this simple apparatus he demonstrated that electric waves move with the speed of light, and that they can be reflected and refracted precisely as if they formed a visible beam. at a certain intensity of strain the air insulation broke down, and the air became a conductor. this phenomenon of passing quite suddenly from a non-conductive to a conductive state is, as we shall duly see, also to be noted when air or other gases are exposed to the x ray. now for the effect of electric waves such as hertz produced, when they impinge upon substances reduced to powder or filings. conductors, such as the metals, are of inestimable service to the electrician; of equal value are non-conductors, such as glass and gutta-percha, as they strictly fence in an electric stream. a third and remarkable vista opens to experiment when it deals with substances which, in their normal state, are non-conductive, but which, agitated by an electric wave, instantly become conductive in a high degree. as long ago as mr. s. a. varley noticed that black lead, reduced to a loose dust, effectually intercepted a current from fifty daniell cells, although the battery poles were very near each other. when he increased the electric tension four- to six-fold, the black-lead particles at once compacted themselves so as to form a bridge of excellent conductivity. on this principle he invented a lightning-protector for electrical instruments, the incoming flash causing a tiny heap of carbon dust to provide it with a path through which it could safely pass to the earth. professor temistocle calzecchi onesti of fermo, in , in an independent series of researches, discovered that a mass of powdered copper is a non-conductor until an electric wave beats upon it; then, in an instant, the mass resolves itself into a conductor almost as efficient as if it were a stout, unbroken wire. professor edouard branly of paris, in , on this principle devised a coherer, which passed from resistance to invitation when subjected to an electric impulse from afar. he enhanced the value of his device by the vital discovery that the conductivity bestowed upon filings by electric discharges could be destroyed by simply shaking or tapping them apart. in a homely way the principle of the coherer is often illustrated in ordinary telegraphic practice. an operator notices that his instrument is not working well, and he suspects that at some point in his circuit there is a defective contact. a little dirt, or oxide, or dampness, has come in between two metallic surfaces; to be sure, they still touch each other, but not in the firm and perfect way demanded for his work. accordingly he sends a powerful current abruptly into the line, which clears its path thoroughly, brushes aside dirt, oxide, or moisture, and the circuit once more is as it should be. in all likelihood, the coherer is acted upon in the same way. among the physicists who studied it in its original form was dr. oliver j. lodge. he improved it so much that, in , at the royal institution in london, he was able to show it as an electric eye that registered the impact of invisible rays at a distance of more than forty yards. he made bold to say that this distance might be raised to half a mile. as early as professor d. e. hughes began a series of experiments in wireless telegraphy, on much the lines which in other hands have now reached commercial as well as scientific success. professor hughes was the inventor of the microphone, and that instrument, he declared, affords an unrivalled means of receiving wireless messages, since it requires no tapping to restore its non-conductivity. in his researches this investigator was convinced that his signals were propagated, not by electro-magnetic induction, but by aerial electric waves spreading out from an electric spark. early in he showed his apparatus to professor stokes, who observed its operation carefully. his dictum was that he saw nothing which could not be explained by known electro-magnetic effects. this erroneous judgment so discouraged professor hughes that he desisted from following up his experiments, and thus, in all probability, the birth of the wireless telegraph was for several years delayed.[ ] [illustration: fig. .--marconi coherer, enlarged view] the coherer, as improved by marconi, is a glass tube about one and one-half inches long and about one-twelfth of an inch in internal diameter. the electrodes are inserted in this tube so as almost to touch; between them is about one-thirtieth of an inch filled with a pinch of the responsive mixture which forms the pivot of the whole contrivance. this mixture is per cent. nickel filings, per cent. hard silver filings, and a mere trace of mercury; the tube is exhausted of air to within one ten-thousandth part (fig. ). how does this trifle of metallic dust manage loudly to utter its signals through a telegraphic sounder, or forcibly indent them upon a moving strip of paper? not directly, but indirectly, as the very last refinement of initiation. let us imagine an ordinary telegraphic battery strong enough loudly to tick out a message. be it ever so strong it remains silent until its circuit is completed, and for that completion the merest touch suffices. now the thread of dust in the coherer forms part of such a telegraphic circuit: as loose dust it is an effectual bar and obstacle, under the influence of electric waves from afar it changes instantly to a coherent metallic link which at once completes the circuit and delivers the message. an electric impulse, almost too attenuated for computation, is here able to effect such a change in a pinch of dust that it becomes a free avenue instead of a barricade. through that avenue a powerful blow from a local store of energy makes itself heard and felt. no device of the trigger class is comparable with this in delicacy. an instant after a signal has taken its way through the coherer a small hammer strikes the tiny tube, jarring its particles asunder, so that they resume their normal state of high resistance. we may well be astonished at the sensitiveness of the metallic filings to an electric wave originating many miles away, but let us remember how clearly the eye can see a bright lamp at the same distance as it sheds a sister beam. thus far no substance has been discovered with a mechanical responsiveness to so feeble a ray of light; in the world of nature and art the coherer stands alone. the electric waves employed by marconi are about four feet long, or have a frequency of about , , per second. such undulations pass readily through brick or stone walls, through common roofs and floors--indeed, through all substances which are non-conductive to electric waves of ordinary length. were the energy of a marconi sending-instrument applied to an arc-lamp, it would generate a beam of a thousand candle-power. we have thus a means of comparing the sensitiveness of the retina to light with the responsiveness of the marconi coherer to electric waves, after both radiations have undergone a journey of miles. an essential feature of this method of etheric telegraphy, due to marconi himself, is the suspension of a perpendicular wire at each terminus, its length twenty feet for stations a mile apart, forty feet for four miles, and so on, the telegraphic distance increasing as the square of the length of suspended wire. in the kingstown regatta, july, , marconi sent from a yacht under full steam a report to the shore without the loss of a moment from start to finish. this feat was repeated during the protracted contest between the _columbia_ and the _shamrock_ yachts in new york bay, october, . on march , , marconi signals put wimereux, two miles north of boulogne, in communication with the south foreland lighthouse, thirty-two miles off.[ ] in august, , during the manoeuvres of the british navy, similar messages were sent as far as eighty miles. it was clearly demonstrated that a new power had been placed in the hands of a naval commander. "a touch on a button in a flagship is all that is now needed to initiate every tactical evolution in a fleet, and insure an almost automatic precision in the resulting movements of the ships. the flashing lantern is superseded at night, flags and the semaphore by day, or, if these are retained, it is for services purely auxiliary. the hideous and bewildering shrieks of the steam-siren need no longer be heard in a fog, and the uncertain system of gun signals will soon become a thing of the past." the interest of the naval and military strategist in the marconi apparatus extends far beyond its communication of intelligence. any electrical appliance whatever may be set in motion by the same wave that actuates a telegraphic sounder. a fuse may be ignited, or a motor started and directed, by apparatus connected with the coherer, for all its minuteness. mr. walter jamieson and mr. john trotter have devised means for the direction of torpedoes by ether waves, such as those set at work in the wireless telegraph. two rods projecting above the surface of the water receive the waves, and are in circuit with a coherer and a relay. at the will of the distant operator a hollow wire coil bearing a current draws in an iron core either to the right or to the left, moving the helm accordingly. as the news of the success of the marconi telegraph made its way to the london stock exchange there was a fall in the shares of cable companies. the fear of rivalry from the new invention was baseless. as but fifteen words a minute are transmissible by the marconi system, it evidently does not compete with a cable, such as that between france and england, which can transmit , words a minute without difficulty. the marconi telegraph comes less as a competitor to old systems than as a mode of communication which creates a field of its own. we have seen what it may accomplish in war, far outdoing any feat possible to other apparatus, acoustic, luminous, or electrical. in quite as striking fashion does it break new ground in the service of commerce and trade. it enables lighthouses continually to spell their names, so that receivers aboard ship may give the steersmen their bearings even in storm and fog. in the crowded condition of the steamship "lanes" which cross the atlantic, a priceless security against collision is afforded the man at the helm. on november , , marconi telegraphed from the american liner _st. paul_ to the needles, sixty-six nautical miles away. on december and , , he received wireless signals near st. john's, newfoundland, sent from poldhu, cornwall, england, or a distance of , miles,--a feat which astonished the world. in many cases the telegraphic business to an island is too small to warrant the laying of a cable; hence we find that trinidad and tobago are to be joined by the wireless system, as also five islands of the hawaiian group, eight to sixty-one miles apart. a weak point in the first marconi apparatus was that anybody within the working radius of the sending-instrument could read its messages. to modify this objection secret codes were at times employed, as in commerce and diplomacy. a complete deliverance from this difficulty is promised in attuning a transmitter and a receiver to the same note, so that one receiver, and no other, shall respond to a particular frequency of impulses. the experiments which indicate success in this vital particular have been conducted by professor lodge. when electricians, twenty years ago, committed energy to a wire and thus enabled it to go round a corner, they felt that they had done well. the hertz waves sent abroad by marconi ask no wire, as they find their way, not round a corner, but through a corner. on may , , a party of french officers on board the _ibis_ at sangatte, near calais, spoke to wimereux by means of a marconi apparatus, with cape grisnez, a lofty promontory, intervening. in ascertaining how much the earth and the sea may obstruct the waves of hertz there is a broad and fruitful field for investigation. "it may be," says professor john trowbridge, "that such long electrical waves roll around the surface of such obstructions very much as waves of sound and of water would do." [illustration: fig. --discontinuous electric waves] [illustration: fig. --wehnelt interrupter] it is singular how discoveries sometimes arrive abreast of each other so as to render mutual aid, or supply a pressing want almost as soon as it is felt. the coherer in its present form is actuated by waves of comparatively low frequency, which rise from zero to full height in extremely brief periods, and are separated by periods decidedly longer (fig. ). what is needed is a plan by which the waves may flow either continuously or so near together that they may lend themselves to attuning. dr. wehnelt, by an extraordinary discovery, may, in all likelihood, provide the lacking device in the form of his interrupter, which breaks an electric circuit as often as two thousand times a second. the means for this amazing performance are simplicity itself (fig. ). a jar, _a_, containing a solution of sulphuric acid has two electrodes immersed in it; one of them is a lead plate of large surface, _b_; the other is a small platinum wire which protrudes from a glass tube, _d_. a current passing through the cell between the two metals at _c_ is interrupted, in ordinary cases five hundred times a second, and in extreme cases four times as often, by bubbles of gas given off from the wire instant by instant. footnotes: [ ] "history of the wireless telegraph," by j. j. fahie. edinburgh and london, william blackwood & sons; new york, dodd, mead & co., . this work is full of interesting detail, well illustrated. [ ] the value of wireless telegraphy in relation to disasters at sea was proved in a remarkable way yesterday morning. while the channel was enveloped in a dense fog, which had lasted throughout the greater part of the night, the east goodwin lightship had a very narrow escape from sinking at her moorings by being run into by the steamship _r. f. matthews_, , tons gross burden, of london, outward bound from the thames. the east goodwin lightship is one of four such vessels marking the goodwin sands, and, curiously enough, it happens to be the one ship which has been fitted out with signor marconi's installation for wireless telegraphy. the vessel was moored about twelve miles to the northeast of the south foreland lighthouse (where there is another wireless-telegraphy installation), and she is about ten miles from the shore, being directly opposite deal. the information regarding the collision was at once communicated by wireless telegraphy from the disabled lightship to the south foreland lighthouse, where mr. bullock, assistant to signor marconi, received the following message: "we have just been run into by the steamer _r. f. matthews_ of london. steamship is standing by us. our bows very badly damaged." mr. bullock immediately forwarded this information to the trinity house authorities at ramsgate.--_times_, april , . electricity, what its mastery means: with a review and a prospect george iles [from "flame, electricity and the camera," copyright by doubleday, page & co., new york.] with the mastery of electricity man enters upon his first real sovereignty of nature. as we hear the whirr of the dynamo or listen at the telephone, as we turn the button of an incandescent lamp or travel in an electromobile, we are partakers in a revolution more swift and profound than has ever before been enacted upon earth. until the nineteenth century fire was justly accounted the most useful and versatile servant of man. to-day electricity is doing all that fire ever did, and doing it better, while it accomplishes uncounted tasks far beyond the reach of flame, however ingeniously applied. we may thus observe under our eyes just such an impetus to human intelligence and power as when fire was first subdued to the purposes of man, with the immense advantage that, whereas the subjugation of fire demanded ages of weary and uncertain experiment, the mastery of electricity is, for the most part, the assured work of the nineteenth century, and, in truth, very largely of its last three decades. the triumphs of the electrician are of absorbing interest in themselves, they bear a higher significance to the student of man as a creature who has gradually come to be what he is. in tracing the new horizons won by electric science and art, a beam of light falls on the long and tortuous paths by which man rose to his supremacy long before the drama of human life had been chronicled or sung. of the strides taken by humanity on its way to the summit of terrestrial life, there are but four worthy of mention as preparing the way for the victories of the electrician--the attainment of the upright attitude, the intentional kindling of fire, the maturing of emotional cries to articulate speech, and the invention of written symbols for speech. as we examine electricity in its fruitage we shall find that it bears the unfailing mark of every other decisive factor of human advance: its mastery is no mere addition to the resources of the race, but a multiplier of them. the case is not as when an explorer discovers a plant hitherto unknown, such as indian corn, which takes its place beside rice and wheat as a new food, and so measures a service which ends there. nor is it as when a prospector comes upon a new metal, such as nickel, with the sole effect of increasing the variety of materials from which a smith may fashion a hammer or a blade. almost infinitely higher is the benefit wrought when energy in its most useful phase is, for the first time, subjected to the will of man, with dawning knowledge of its unapproachable powers. it begins at once to marry the resources of the mechanic and the chemist, the engineer and the artist, with issue attested by all its own fertility, while its rays reveal province after province undreamed of, and indeed unexisting, before its advent. every other primal gift of man rises to a new height at the bidding of the electrician. all the deftness and skill that have followed from the upright attitude, in its creation of the human hand, have been brought to a new edge and a broader range through electric art. between the uses of flame and electricity have sprung up alliances which have created new wealth for the miner and the metal-worker, the manufacturer and the shipmaster, with new insights for the man of research. articulate speech borne on electric waves makes itself heard half-way across america, and words reduced to the symbols of symbols--expressed in the perforations of a strip of paper--take flight through a telegraph wire at twenty-fold the pace of speech. because the latest leap in knowledge and faculty has been won by the electrician, he has widened the scientific outlook vastly more than any explorer who went before. beyond any predecessor, he began with a better equipment and a larger capital to prove the gainfulness which ever attends the exploiting a supreme agent of discovery. as we trace a few of the unending interlacements of electrical science and art with other sciences and arts, and study their mutually stimulating effects, we shall be reminded of a series of permutations where the latest of the factors, because latest, multiplies all prior factors in an unexampled degree.[ ] we shall find reason to believe that this is not merely a suggestive analogy, but really true as a tendency, not only with regard to man's gains by the conquest of electricity, but also with respect to every other signal victory which has brought him to his present pinnacle of discernment and rule. if this permutative principle in former advances lay undetected, it stands forth clearly in that latest accession to skill and interpretation which has been ushered in by franklin and volta, faraday and henry. although of much less moment than the triumphs of the electrician, the discovery of photography ranks second in importance among the scientific feats of the nineteenth century. the camera is an artificial eye with almost every power of the human retina, and with many that are denied to vision--however ingeniously fortified by the lens-maker. a brief outline of photographic history will show a parallel to the permutative impulse so conspicuous in the progress of electricity. at the points where the electrician and the photographer collaborate we shall note achievements such as only the loftiest primal powers may evoke. a brief story of what electricity and its necessary precursor, fire, have done and promise to do for civilization, may have attraction in itself; so, also, may a review, though most cursory, of the work of the camera and all that led up to it: for the provinces here are as wide as art and science, and their bounds comprehend well-nigh the entirety of human exploits. and between the lines of this story we may read another--one which may tell us something of the earliest stumblings in the dawn of human faculty. when we compare man and his next of kin, we find between the two a great gulf, surely the widest betwixt any allied families in nature. can a being of intellect, conscience, and aspiration have sprung at any time, however remote, from the same stock as the orang and the chimpanzee? since , when darwin published his "origin of species," the theory of evolution has become so generally accepted that to-day it is little more assailed than the doctrine of gravitation. and yet, while the average man of intelligence bows to the formula that all which now exists has come from the simplest conceivable state of things,--a universal nebula, if you will,--in his secret soul he makes one exception--himself. that there is a great deal more assent than conviction in the world is a chiding which may come as justly from the teacher's table as from the preacher's pulpit. now, if we but catch the meaning of man's mastery of electricity, we shall have light upon his earlier steps as a fire-kindler, and as a graver of pictures and symbols on bone and rock. as we thus recede from civilization to primeval savagery, the process of the making of man may become so clear that the arguments of darwin shall be received with conviction, and not with silent repulse. as we proceed to recall, one by one, the salient chapters in the history of fire, and of the arts of depiction that foreran the camera, we shall perceive a truth of high significance. we shall see that, while every new faculty has its roots deep in older powers, and while its growth may have been going on for age after age, yet its flowering may be as the event of a morning. even as our gardens show us the century-plants, once supposed to bloom only at the end of a hundred years, so history, in the large, exhibits discoveries whose harvests are gathered only after the lapse of æons instead of years. the arts of fire were slowly elaborated until man had produced the crucible and the still, through which his labours culminated in metals purified, in acids vastly more corrosive than those of vegetation, in glass and porcelain equally resistant to flame and the electric wave. these were combined in an hour by volta to build his cell, and in that hour began a new era for human faculty and insight. it is commonly imagined that the progress of humanity has been at a tolerably uniform pace. our review of that progress will show that here and there in its course have been _leaps_, as radically new forces have been brought under the dominion of man. we of the electric revolution are sharply marked off from our great-grandfathers, who looked upon the cell of volta as a curious toy. they, in their turn, were profoundly differenced from the men of the seventeenth century, who had not learned that flame could outvie the horse as a carrier, and grind wheat better than the mill urged by the breeze. and nothing short of an abyss stretches between these men and their remote ancestors, who had not found a way to warm their frosted fingers or lengthen with lamp or candle the short, dark days of winter. throughout the pages of this book there will be some recital of the victories won by the fire-maker, the electrician, the photographer, and many more in the peerage of experiment and research. underlying the sketch will appear the significant contrast betwixt accessions of minor and of supreme dignity. the finding a new wood, such as that of the yew, means better bows for the archer, stronger handles for the tool-maker; the subjugation of a universal force such as fire, or electricity, stands for the exaltation of power in every field of toil, for the creation of a new earth for the worker, new heavens for the thinker. as a corollary, we shall observe that an increasing width of gap marks off the successive stages of human progress from each other, so that its latest stride is much the longest and most decisive. and it will be further evident that, while every new faculty is of age-long derivation from older powers and ancient aptitudes, it nevertheless comes to the birth in a moment, as it were, and puts a strain of probably fatal severity on those contestants who miss the new gift by however little. we shall, therefore, find that the principle of permutation, here merely indicated, accounts in large measure for three cardinal facts in the history of man: first, his leaps forward; second, the constant accelerations in these leaps; and third, the gap in the record of the tribes which, in the illimitable past, have succumbed as forces of a new edge and sweep have become engaged in the fray.[ ] the interlacements of the arts of fire and of electricity are intimate and pervasive. while many of the uses of flame date back to the dawn of human skill, many more have become of new and higher value within the last hundred years. fire to-day yields motive power with tenfold the economy of a hundred years ago, and motive power thus derived is the main source of modern electric currents. in metallurgy there has long been an unwitting preparation for the advent of the electrician, and here the services of fire within the nineteenth century have won triumphs upon which the later successes of electricity largely proceed. in producing alloys, and in the singular use of heat to effect its own banishment, novel and radical developments have been recorded within the past decade or two. these, also, make easier and bolder the electrician's tasks. the opening chapters of this book will, therefore, bestow a glance at the principal uses of fire as these have been revealed and applied. this glance will make clear how fire and electricity supplement each other with new and remarkable gains, while in other fields, not less important, electricity is nothing else than a supplanter of the very force which made possible its own discovery and impressment. [here follow chapters which outline the chief applications of flame and of electricity.] let us compare electricity with its precursor, fire, and we shall understand the revolution by which fire is now in so many tasks supplanted by the electric pulse which, the while, creates for itself a thousand fields denied to flame. copper is an excellent thermal conductor, and yet it transmits heat almost infinitely more slowly than it conveys electricity. one end of a thick copper rod ten feet long may be safely held in the hand while the other end is heated to redness, yet one millionth part of this same energy, if in the form of electricity, would traverse the rod in one , , th part of a second. compare next electricity with light, often the companion of heat. light travels in straight lines only; electricity can go round a corner every inch for miles, and, none the worse, yield a brilliant beam at the end of its journey. indirectly, therefore, electricity enables us to conduct either heat or light as if both were flexible pencils of rays, and subject to but the smallest tolls in their travel. we have remarked upon such methods as those of the electric welder which summon intense heat without fire, and we have glanced at the electric lamps which shine just because combustion is impossible through their rigid exclusion of air. then for a moment we paused to look at the plating baths which have developed themselves into a commanding rivalry with the blaze of the smelting furnace, with the flame which from time immemorial has filled the ladle of the founder and moulder. thus methods that commenced in dismissing flame end boldly by dispossessing heat itself. but, it may be said, this usurping electricity usually finds its source, after all, in combustion under a steam-boiler. true, but mark the harnessing of niagara, of the lachine rapids near montreal, of a thousand streams elsewhere. in the near future motive power of nature's giving is to be wasted less and less, and perforce will more and more exclude heat from the chain of transformations which issue in the locomotive's flight, in the whirl of factory and mill. thus in some degree is allayed the fear, never well grounded, that when the coal fields of the globe are spent civilization must collapse. as the electrician hears this foreboding he recalls how much fuel is wasted in converting heat into electricity. he looks beyond either turbine or shaft turned by wind or tide, and, remembering that the metal dissolved in his battery yields at his will its full content of energy, either as heat or electricity, he asks, why may not coal or forest tree, which are but other kinds of fuel, be made to do the same? one of the earliest uses of light was a means of communicating intelligence, and to this day the signal lamp and the red fire of the mariner are as useful as of old. but how much wider is the field of electricity as it creates the telegraph and the telephone! in the telegraph we have all that a pencil of light could be were it as long as an equatorial girdle and as flexible as a silken thread. in the telephone for nearly two thousand miles the pulsations of the speaker's voice are not only audible, but retain their characteristic tones. in the field of mechanics electricity is decidedly preferable to any other agent. heat may be transformed into motive power by a suitable engine, but there its adaptability is at an end. an electric current drives not only a motor, but every machine and tool attached to the motor, the whole executing tasks of a delicacy and complication new to industrial art. on an electric railroad an identical current propels the train, directs it by telegraph, operates its signals, provides it with light and heat, while it stands ready to give constant verbal communication with any station on the line, if this be desired. in the home electricity has equal versatility, at once promoting healthfulness, refinement and safety. its tiny button expels the hazardous match as it lights a lamp which sends forth no baleful fumes. an electric fan brings fresh air into the house--in summer as a grateful breeze. simple telephones, quite effective for their few yards of wire, give a better because a more flexible service than speaking-tubes. few invalids are too feeble to whisper at the light, portable ear of metal. sewing-machines and the more exigent apparatus of the kitchen and laundry transfer their demands from flagging human muscles to the tireless sinews of electric motors--which ask no wages when they stand unemployed. similar motors already enjoy favour in working the elevators of tall dwellings in cities. if a householder is timid about burglars, the electrician offers him a sleepless watchman in the guise of an automatic alarm; if he has a dread of fire, let him dispose on his walls an array of thermometers that at the very inception of a blaze will strike a gong at headquarters. but these, after all, are matters of minor importance in comparison with the foundations upon which may be reared, not a new piece of mechanism, but a new science or a new art. in the recent swift subjugation of the territory open alike to the chemist and the electrician, where each advances the quicker for the other's company, we have fresh confirmation of an old truth--that the boundary lines which mark off one field of science from another are purely artificial, are set up only for temporary convenience. the chemist has only to dig deep enough to find that the physicist and himself occupy common ground. "delve from the surface of your sphere to its heart, and at once your radius joins every other." even the briefest glance at electro-chemistry should pause to acknowledge its profound debt to the new theories as to the bonding of atoms to form molecules, and of the continuity between solution and electrical dissociation. however much these hypotheses may be modified as more light is shed on the geometry and the journeyings of the molecule, they have for the time being recommended themselves as finder-thoughts of golden value. these speculations of the chemist carry him back perforce to the days of his childhood. as he then joined together his black and white bricks he found that he could build cubes of widely different patterns. it was in propounding a theory of molecular architecture that kekulé gave an impetus to a vast and growing branch of chemical industry--that of the synthetic production of dyes and allied compounds. it was in pure research, in paths undirected to the market-place, that such theories have been thought out. let us consider electricity as an aid to investigation conducted for its own sake. the chief physical generalization of our time, and of all time, the persistence of force, emerged to view only with the dawn of electric art. when it was observed that electricity might become heat, light, chemical action, or mechanical motion, that in turn any of these might produce electricity, it was at once indicated that all these phases of energy might differ from each other only as the movements in circles, volutes, and spirals of ordinary mechanism. the suggestion was confirmed when electrical measurers were refined to the utmost precision, and a single quantum of energy was revealed a very proteus in its disguises, yet beneath these disguises nothing but constancy itself. "there is that scattereth, and yet increaseth; and there is that withholdeth more than is meet, but it tendeth to poverty." because the geometers of old patiently explored the properties of the triangle, the circle, and the ellipse, simply for pure love of truth, they laid the corner-stones for the arts of the architect, the engineer, and the navigator. in like manner it was the disinterested work of investigation conducted by ampère, faraday, henry and their compeers, in ascertaining the laws of electricity which made possible the telegraph, the telephone, the dynamo, and the electric furnace. the vital relations between pure research and economic gain have at last worked themselves clear. it is perfectly plain that a man who has it in him to discover laws of matter and energy does incomparably more for his kind than if he carried his talents to the mint for conversion into coin. the voyage of a columbus may not immediately bear as much fruit as the uncoverings of a mine prospector, but in the long run a columbus makes possible the finding many mines which without him no prospector would ever see. therefore let the seed-corn of knowledge be planted rather than eaten. but in choosing between one research and another it is impossible to foretell which may prove the richer in its harvests; for instance, all attempts thus far economically to oxidize carbon for the production of electricity have failed, yet in observations that at first seemed equally barren have lain the hints to which we owe the incandescent lamp and the wireless telegraph. perhaps the most promising field of electrical research is that of discharges at high pressures; here the leading american investigators are professor john trowbridge and professor elihu thomson. employing a tension estimated at one and a half millions volts, professor trowbridge has produced flashes of lightning six feet in length in atmospheric air; in a tube exhausted to one-seventh of atmospheric pressure the flashes extended themselves to forty feet. according to this inquirer, the familiar rending of trees by lightning is due to the intense heat developed in an instant by the electric spark; the sudden expansion of air or steam in the cavities of the wood causes an explosion. the experiments of professor thomson confront him with some of the seeming contradictions which ever await the explorer of new scientific territory. in the atmosphere an electrical discharge is facilitated when a metallic terminal (as a lightning rod) is shaped as a point; under oil a point is the form least favourable to discharge. in the same line of paradox it is observed that oil steadily improves in its insulating effect the higher the electrical pressure committed to its keeping; with air as an insulator the contrary is the fact. these and a goodly array of similar puzzles will, without doubt, be cleared up as students in the twentieth century pass from the twilight of anomaly to the sunshine of ascertained law. "before there can be applied science there must be science to apply," and it is by enabling the investigator to know nature under a fresh aspect that electricity rises to its highest office. the laboratory routine of ascertaining the conductivity, polarisability, and other electrical properties of matter is dull and exacting work, but it opens to the student new windows through which to peer at the architecture of matter. that architecture, as it rises to his view, discloses one law of structure after another; what in a first and clouded glance seemed anomaly is now resolved and reconciled; order displays itself where once anarchy alone appeared. when the investigator now needs a substance of peculiar properties he knows where to find it, or has a hint for its creation--a creation perhaps new in the history of the world. as he thinks of the wealth of qualities possessed by his store of alloys, salts, acids, alkalies, new uses for them are borne into his mind. yet more--a new orchestration of inquiry is possible by means of the instruments created for him by the electrician, through the advances in method which these instruments effect. with a second and more intimate point of view arrives a new trigonometry of the particle, a trigonometry inconceivable in pre-electric days. hence a surround is in progress which early in the twentieth century may go full circle, making atom and molecule as obedient to the chemist as brick and stone are to the builder now. the laboratory investigator and the commercial exploiter of his discoveries have been by turns borrower and lender, to the great profit of both. what leyden jar could ever be constructed of the size and revealing power of an atlantic cable? and how many refinements of measurement, of purification of metals, of precision in manufacture, have been imposed by the colossal investments in deep-sea telegraphy alone! when a current admitted to an ocean cable, such as that between brest and new york, can choose for its path either , miles of copper wire or a quarter of an inch of gutta-percha, there is a dangerous opportunity for escape into the sea, unless the current is of nicely adjusted strength, and the insulator has been made and laid with the best-informed skill, the most conscientious care. in the constant tests required in laying the first cables lord kelvin (then professor william thomson) felt the need for better designed and more sensitive galvanometers or current measurers. his great skill both as a mathematician and a mechanician created the existing instruments, which seem beyond improvement. they serve not only in commerce and manufacture, but in promoting the strictly scientific work of the laboratory. now that electricity purifies copper as fire cannot, the mathematician is able to treat his problems of long-distance transmission, of traction, of machine design, with an economy and certainty impossible when his materials were not simply impure, but impure in varying and indefinite degrees. the factory and the workshop originally took their magneto-machines from the experimental laboratory; they have returned them remodelled beyond recognition as dynamos and motors of almost ideal effectiveness. a galvanometer actuated by a thermo-electric pile furnishes much the most sensitive means of detecting changes of temperature; hence electricity enables the physicist to study the phenomena of heat with new ease and precision. it was thus that professor tyndall conducted the classical researches set forth in his "heat as a mode of motion," ascertaining the singular power to absorb terrestrial heat which makes the aqueous vapours of the atmosphere act as an indispensable blanket to the earth. and how vastly has electricity, whether in the workshop or laboratory, enlarged our conceptions of the forces that thrill space, of the substances, seemingly so simple, that surround us--substances that propound questions of structure and behaviour that silence the acutest investigator. "you ask me," said a great physicist, "if i have a theory of the _universe_? why, i haven't even a theory of _magnetism_!" the conventional phrase "conducting a current" is now understood to be mere figure of speech; it is thought that a wire does little else than give direction to electric energy. pulsations of high tension have been proved to be mainly superficial in their journeys, so that they are best conveyed (or convoyed) by conductors of tubular form. and what is it that moves when we speak of conduction? it seems to be now the molecule of atomic chemistry, and anon the same ether that undulates with light or radiant heat. indeed, the conquest of electricity means so much because it impresses the molecule and the ether into service as its vehicles of communication. instead of the old-time masses of metal, or bands of leather, which moved stiffly through ranges comparatively short, there is to-day employed a medium which may traverse , miles in a second, and with resistances most trivial in contrast with those of mechanical friction. and what is friction in the last analysis but the production of motion in undesired forms, the allowing valuable energy to do useless work? in that amazing case of long distance transmission, common sunshine, a solar beam arrives at the earth from the sun not one whit the weaker for its excursion of , , miles. it is highly probable that we are surrounded by similar cases of the total absence of friction in the phenomena of both physics and chemistry, and that art will come nearer and nearer to nature in this immunity is assured when we see how many steps in that direction have already been taken by the electrical engineer. in a preceding page a brief account was given of the theory that gases and vapours are in ceaseless motion. this motion suffers no abatement from friction, and hence we may infer that the molecules concerned are perfectly elastic. the opinion is gaining ground among physicists that all the properties of matter, transparency, chemical combinability, and the rest, are due to immanent motion in particular orbits, with diverse velocities. if this be established, then these motions also suffer no friction, and go on without resistance forever. as the investigators in the vanguard of science discuss the constitution of matter, and weave hypotheses more or less fruitful as to the interplay of its forces, there is a growing faith that the day is at hand when the tie between electricity and gravitation will be unveiled--when the reason why matter has weight will cease to puzzle the thinker. who can tell what relief of man's estate may be bound up with the ability to transform any phase of energy into any other without the circuitous methods and serious losses of to-day! in the sphere of economic progress one of the supreme advances was due to the invention of money, the providing a medium for which any salable thing may be exchanged, with which any purchasable thing may be bought. as soon as a shell, or a hide, or a bit of metal was recognized as having universal convertibility, all the delays and discounts of barter were at an end. in the world of physics and chemistry the corresponding medium is electricity; let it be produced as readily as it produces other modes of motion, and human art will take a stride forward such as when volta disposed his zinc and silver discs together, or when faraday set a magnet moving around a copper wire. for all that the electric current is not as yet produced as economically as it should be, we do wrong if we regard it as an infant force. however much new knowledge may do with electricity in the laboratory, in the factory, or in the exchange, some of its best work is already done. it is not likely ever to perform a greater feat than placing all mankind within ear-shot of each other. were electricity unmastered there could be no democratic government of the united states. to-day the drama of national affairs is more directly in view of every american citizen than, a century ago, the public business of delaware could be to the men of that little state. and when on the broader stage of international politics misunderstandings arise, let us note how the telegraph has modified the hard-and-fast rules of old-time diplomacy. to-day, through the columns of the press, the facts in controversy are instantly published throughout the world, and thus so speedily give rise to authoritative comment that a severe strain is put upon negotiators whose tradition it is to be both secret and slow. railroads, with all they mean for civilization, could not have extended themselves without the telegraph to control them. and railroads and telegraphs are the sinews and nerves of national life, the prime agencies in welding the diverse and widely separated states and territories of the union. a boston merchant builds a cotton-mill in georgia; a new york capitalist opens a copper-mine in arizona. the telegraph which informs them day by day how their investments prosper tells idle men where they can find work, where work can seek idle men. chicago is laid in ashes, charleston topples in earthquake, johnstown is whelmed in flood, and instantly a continent springs to their relief. and what benefits issue in the strictly commercial uses of the telegraph! at its click both locomotive and steamship speed to the relief of famine in any quarter of the globe. in times of plenty or of dearth the markets of the globe are merged and are brought to every man's door. not less striking is the neighbourhood guild of science, born, too, of the telegraph. the day after röntgen announced his x rays, physicists on every continent were repeating his experiments--were applying his discovery to the healing of the wounded and diseased. let an anti-toxin for diphtheria, consumption, or yellow fever be proposed, and a hundred investigators the world over bend their skill to confirm or disprove, as if the suggester dwelt next door. on a stage less dramatic, or rather not dramatic at all, electricity works equal good. its motor freeing us from dependence on the horse is spreading our towns and cities into their adjoining country. field and garden compete with airless streets. the sunny cottage is in active rivalry with the odious tenement-house. it is found that transportation within the gates of a metropolis has an importance second only to the means of transit which links one city with another. the engineer is at last filling the gap which too long existed between the traction of horses and that of steam. in point of speed, cleanliness, and comfort such an electric subway as that of south london leaves nothing to be desired. throughout america electric roads, at first suburban, are now fast joining town to town and city to city, while, as auxiliaries to steam railroads, they place sparsely settled communities in the arterial current of the world, and build up a ready market for the dairyman and the fruit-grower. in its saving of what mr. oscar t. crosby has called "man-hours" the third-rail system is beginning to oust steam as a motive power from trunk-lines. already shrewd railroad managers are granting partnerships to the electricians who might otherwise encroach upon their dividends. a service at first restricted to passengers has now extended itself to the carriage of letters and parcels, and begins to reach out for common freight. we may soon see the farmer's cry for good roads satisfied by good electric lines that will take his crops to market much more cheaply and quickly than horses and macadam ever did. in cities, electromobile cabs and vans steadily increase in numbers, furthering the quiet and cleanliness introduced by the trolley car. a word has been said about the blessings which electricity promises to country folk, yet greater are the boons it stands ready to bestow in the hives of population. until a few decades ago the water-supply of cities was a matter not of municipal but of individual enterprise; water was drawn in large part from wells here and there, from lines of piping laid in favoured localities, and always insufficient. many an epidemic of typhoid fever was due to the contamination of a spring by a cesspool a few yards away. to-day a supply such as that of new york is abundant and cheap because it enters every house. let a centralized electrical service enjoy a like privilege, and it will offer a current which is heat, light, chemical energy, or motive power, and all at a wage lower than that of any other servant. unwittingly, then, the electrical engineer is a political reformer of high degree, for he puts a new premium upon ability and justice at the city hall. his sole condition is that electricity shall be under control at once competent and honest. let us hope that his plea, joined to others as weighty, may quicken the spirit of civic righteousness so that some of the richest fruits ever borne in the garden of science and art may not be proffered in vain. flame, the old-time servant, is individual; electricity, its successor and heir, is collective. flame sits upon the hearth and draws a family together; electricity, welling from a public source, may bind into a unit all the families of a vast city, because it makes the benefit of each the interest of all. but not every promise brought forward in the name of the electrician has his assent or sanction. so much has been done by electricity, and so much more is plainly feasible, that a reflection of its triumphs has gilded many a baseless dream. one of these is that the cheap electric motor, by supply power at home, will break up the factory system, and bring back the domestic manufacturing of old days. but if this power cost nothing at all the gift would leave the factory unassailed; for we must remember that power is being steadily reduced in cost from year to year, so that in many industries it has but a minor place among the expenses of production. the strength and profit of the factory system lie in its assembling a wide variety of machines, the first delivering its product to the second for another step toward completion, and so on until a finished article is sent to the ware-room. it is this minute subdivision of labour, together with the saving and efficiency that inure to a business conducted on an immense scale under a single manager, that bids us believe that the factory has come to stay. to be sure, a weaver, a potter, or a lens-grinder of peculiar skill may thrive at his loom or wheel at home; but such a man is far from typical in modern manufacture. besides, it is very questionable whether the lamentations over the home industries of the past do not ignore evil concomitants such as still linger in the home industries of the present--those of the sweater's den, for example. this rapid survey of what electricity has done and may yet do--futile expectation dismissed--has shown it the creator of a thousand material resources, the perfector of that communication of things, of power, of thought, which in every prior stage of advancement has marked the successive lifts of humanity. it was much when the savage loaded a pack upon a horse or an ox instead of upon his own back; it was yet more when he could make a beacon-flare give news or warning to a whole country-side, instead of being limited to the messages which might be read in his waving hands. all that the modern engineer was able to do with steam for locomotion is raised to a higher plane by the advent of his new power, while the long-distance transmission of electrical energy is contracting the dimensions of the planet to a scale upon which its cataracts in the wilderness drive the spindles and looms of the factory town, or illuminate the thoroughfares of cities. beyond and above all such services as these, electricity is the corner-stone of physical generalization, a revealer of truths impenetrable by any other ray. the subjugation of fire has done much in giving man a new independence of nature, a mighty armoury against evil. in curtailing the most arduous and brutalizing forms of toil, electricity, that subtler kind of fire, carries this emancipation a long step further, and, meanwhile, bestows upon the poor many a luxury which but lately was the exclusive possession of the rich. in more closely binding up the good of the bee with the welfare of the hive, it is an educator and confirmer of every social bond. in so far as it proffers new help in the war on pain and disease it strengthens the confidence of man in an order of right and happiness which for so many dreary ages has been a matter rather of hope than of vision. are we not, then, justified in holding electricity to be a multiplier of faculty and insight, a means of dignifying mind and soul, unexampled since man first kindled fire and rejoiced? we have traced how dexterity rose to fire-making, how fire-making led to the subjugation of electricity. much of the most telling work of fire can be better done by its great successor, while electricity performs many tasks possible only to itself. unwitting truth there was in the simple fable of the captive who let down a spider's film, that drew up a thread, which in turn brought up a rope--and freedom. it was in on the threshold of the nineteenth century, that volta devised the first electric battery. in a hundred years the force then liberated has vitally interwoven itself with every art and science, bearing fruit not to be imagined even by men of the stature of watt, lavoisier, or humboldt. compare this rapid march of conquest with the slow adaptation, through age after age, of fire to cooking, smelting, tempering. yet it was partly, perhaps mainly, because the use of fire had drawn out man's intelligence and cultivated his skill that he was ready in the fulness of time so quickly to seize upon electricity and subdue it. electricity is as legitimately the offspring of fire as fire of the simple knack in which one savage in ten thousand was richer than his fellows. the principle of permutation, suggested in both victories, interprets not only how vast empire is won by a new weapon of prime dignity; it explains why such empires are brought under rule with ever-accelerated pace. every talent only pioneers the way for the richer talents which are born from it. footnotes: [ ] permutations are the various ways in which two or more different things may be arranged in a row, all the things appearing in each row. permutations are readily illustrated with squares or cubes of different colours, with numbers, or letters. permutations of two elements, and , are ( x ) two; , ; , ; or _a_, _b_; _b_, _a_. of three elements the permutations are ( x x ) six; , , ; , , ; , , ; , , ; , , ; , , ; or _a_, _b_, _c_; _a_, _c_, _b_; _b_, _a_, _c_; _b_, _c_, _a_; _c_, _a_, _b_; _c_, _b_, _a_. of four elements the permutations are ( x x x ) twenty-four; of five elements, one hundred and twenty, and so on. a new element or permutator multiplies by an increasing figure all the permutations it finds. [ ] some years ago i sent an outline of this argument to herbert spencer, who replied: "i recognize a novelty and value in your inference that the law implies an increasing width of gap between lower and higher types as evolution advances." count rumford identifies heat with motion. [benjamin thompson, who received the title of count rumford from the elector of bavaria, was born in woburn, massachusetts, in . when thirty-one years of age he settled in munich, where he devoted his remarkable abilities to the public service. twelve years afterward he removed to england; in he founded the royal institution of london, since famous as the theatre of the labours of davy, faraday, tyndall, and dewar. he bequeathed to harvard university a fund to endow a professorship of the application of science to the art of living: he instituted a prize to be awarded by the american academy of sciences for the most important discoveries and improvements relating to heat and light. in he married the widow of the illustrious chemist lavoisier: he died in . count rumford on january , , read a paper before the royal society entitled "an enquiry concerning the source of heat which is excited by friction." the experiments therein detailed proved that heat is identical with motion, as against the notion that heat is matter. he thus laid the corner-stone of the modern theory that heat light, electricity, magnetism, chemical action, and all other forms of energy are in essence motion, are convertible into one another, and as motion are indestructible. the following abstract of count rumford's paper is taken from "heat as a mode of motion," by professor john tyndall, published by d. appleton & co., new york. this work and "the correlation and conservation of forces," edited by dr. e. l. youmans, published by the same house, will serve as a capital introduction to the modern theory that energy is motion which, however varied in its forms, is changeless in its quantity.] being engaged in superintending the boring of cannon in the workshops of the military arsenal at munich, count rumford was struck with the very considerable degree of heat which a brass gun acquires, in a short time, in being bored, and with the still more intense heat (much greater than that of boiling water) of the metallic chips separated from it by the borer, he proposed to himself the following questions: "whence comes the heat actually produced in the mechanical operations above mentioned? "is it furnished by the metallic chips which are separated from the metal?" if this were the case, then the _capacity for heat_ of the parts of the metal so reduced to chips ought not only to be changed, but the change undergone by them should be sufficiently great to account for _all_ the heat produced. no such change, however, had taken place, for the chips were found to have the same capacity as slices of the same metal cut by a fine saw, where heating was avoided. hence, it is evident, that the heat produced could not possibly have been furnished at the expense of the latent heat of the metallic chips. rumford describes these experiments at length, and they are conclusive. he then designed a cylinder for the express purpose of generating heat by friction, by having a blunt borer forced against its solid bottom, while the cylinder was turned around its axis by the force of horses. to measure the heat developed, a small round hole was bored in the cylinder for the purpose of introducing a small mercurial thermometer. the weight of the cylinder was . pounds avoirdupois. the borer was a flat piece of hardened steel, . of an inch thick, four inches long, and nearly as wide as the cavity of the bore of the cylinder, namely, three and one-half inches. the area of the surface by which its end was in contact with the bottom of the bore was nearly two and one-half inches. at the beginning of the experiment the temperature of the air in the shade, and also that of the cylinder, was ° fahr. at the end of thirty minutes, and after the cylinder had made revolutions round its axis, the temperature was found to be °. having taken away the borer, he now removed the metallic dust, or rather scaly matter, which had been detached from the bottom of the cylinder by the blunt steel borer, and found its weight to be grains troy. "is it possible," he exclaims, "that the very considerable quantity of heat produced in this experiment--a quantity which actually raised the temperature of above pounds of gun-metal at least ° of fahrenheit's thermometer--could have been furnished by so inconsiderable a quantity of metallic dust and this merely in consequence of a _change_ in its capacity of heat?" "but without insisting on the improbability of this supposition, we have only to recollect that from the results of actual and decisive experiments, made for the express purpose of ascertaining that fact, the capacity for heat for the metal of which great guns are cast is _not sensibly changed_ by being reduced to the form of metallic chips, and there does not seem to be any reason to think that it can be much changed, if it be changed at all, in being reduced to much smaller pieces by a borer which is less sharp." he next surrounded his cylinder by an oblong deal-box, in such a manner that the cylinder could turn water-tight in the centre of the box, while the borer was pressed against the bottom of the cylinder. the box was filled with water until the entire cylinder was covered, and then the apparatus was set in action. the temperature of the water on commencing was °. "the result of this beautiful experiment," writes rumford, "was very striking, and the pleasure it afforded me amply repaid me for all the trouble i had had in contriving and arranging the complicated machinery used in making it. the cylinder had been in motion but a short time, when i perceived, by putting my hand into the water, and touching the outside of the cylinder, that heat was generated. "at the end of one hour the fluid, which weighed . pounds, or two and one-half gallons, had its temperature raised forty-seven degrees, being now °. "in thirty minutes more, or one hour and thirty minutes after the machinery had been set in motion, the heat of the water was °. "at the end of two hours from the beginning, the temperature was °. "at two hours and twenty minutes it was °, and at two hours and thirty minutes it _actually boiled_!" "it would be difficult to describe the surprise and astonishment expressed in the countenances of the bystanders on seeing so large a quantity of water heated, and actually made to boil, without any fire. though, there was nothing that could be considered very surprising in this matter, yet i acknowledge fairly that it afforded me a degree of childish pleasure which, were i ambitious of the reputation of a grave philosopher, i ought most certainly rather to hide than to discover." he then carefully estimates the quantity of heat possessed by each portion of his apparatus at the conclusion of the experiment, and, adding all together, finds a total sufficient to raise . pounds of ice-cold water to its boiling point, or through ° fahrenheit. by careful calculation, he finds this heat equal to that given out by the combustion of , . grains (equal to four and eight-tenths ounces troy) of wax. he then determines the "_celerity_" with which the heat was generated, summing up thus: "from the results of these computations, it appears that the quantity of heat produced equably, or in a continuous stream, if i may use the expression, by the friction of the blunt steel borer against the bottom of the hollow metallic cylinder, was _greater_ than that produced in the combustion of nine _wax-candles_, each three-quarters of an inch in diameter, all burning together with clear bright flames. "one horse would have been equal to the work performed, though two were actually employed. heat may thus be produced merely by the strength of a horse, and, in a case of necessity, this heat might be used in cooking victuals. but no circumstances could be imagined in which this method of procuring heat would be advantageous, for more heat might be obtained by using the fodder necessary for the support of a horse as fuel." [this is an extremely significant passage, intimating as it does, that rumford saw clearly that the force of animals was derived from the food; _no creation of force_ taking place in the animal body.] "by meditating on the results of all these experiments, we are naturally brought to that great question which has so often been the subject of speculation among philosophers, namely, what is heat--is there any such thing as an _igneous fluid_? is there anything that, with propriety, can be called caloric? "we have seen that a very considerable quantity of heat may be excited by the friction of two metallic surfaces, and given off in a constant stream or flux _in all directions_, without interruption or intermission, and without any signs of _diminution_ or _exhaustion_. in reasoning on this subject we must not forget _that most remarkable circumstance_, that the source of the heat generated by friction in these experiments appeared evidently to be _inexhaustible_. [the italics are rumford's.] it is hardly necessary to add, that anything which any _insulated_ body or system of bodies can continue to furnish _without limitation_ cannot possibly be a _material substance_; and it appears to me to be extremely difficult, if not quite impossible, to form any distinct idea of anything capable of being excited and communicated in those experiments, except it be motion." when the history of the dynamical theory of heat is written, the man who, in opposition to the scientific belief of his time, could experiment and reason upon experiment, as rumford did in the investigation here referred to, cannot be lightly passed over. hardly anything more powerful against the materiality of heat has been since adduced, hardly anything more conclusive in the way of establishing that heat is, what rumford considered it to be, _motion_. victory of the "rocket" locomotive. [part of chapter xii. part ii, of "the life of george stephenson and of his son, robert stephenson," by samuel smiles new york, harper & brothers, .] the works of the liverpool and manchester railway were now approaching completion. but, strange to say, the directors had not yet decided as to the tractive power to be employed in working the line when open for traffic. the differences of opinion among them were so great as apparently to be irreconcilable. it was necessary, however, that they should, come to some decision without further loss of time, and many board meetings were accordingly held to discuss the subject. the old-fashioned and well-tried system of horse-haulage was not without its advocates; but, looking at the large amount of traffic which there was to be conveyed, and at the probable delay in the transit from station to station if this method were adopted, the directors, after a visit made by them to the northumberland and durham railways in , came to the conclusion that the employment of horse-power was inadmissible. fixed engines had many advocates; the locomotive very few: it stood as yet almost in a minority of one--george stephenson.... in the meantime the discussion proceeded as to the kind of power to be permanently employed for the working of the railway. the directors were inundated with schemes of all sorts for facilitating locomotion. the projectors of england, france, and america seemed to be let loose upon them. there were plans for working the waggons along the line by water-power. some proposed hydrogen, and others carbonic acid gas. atmospheric pressure had its eager advocates. and various kinds of fixed and locomotive steam-power were suggested. thomas gray urged his plan of a greased road with cog-rails; and messrs. vignolles and ericsson recommended the adoption of a central friction-rail, against which two horizontal rollers under the locomotive, pressing upon the sides of this rail, were to afford the means of ascending the inclined planes.... the two best practical engineers of the day concurred in reporting substantially in favour of the employment of fixed engines. not a single professional man of eminence could be found to coincide with the engineer of the railway in his preference for locomotive over fixed engine power. he had scarcely a supporter, and the locomotive system seemed on the eve of being abandoned. still he did not despair. with the profession against him, and public opinion against him--for the most frightful stories went abroad respecting the dangers, the unsightliness, and the nuisance which the locomotive would create--stephenson held to his purpose. even in this, apparently the darkest hour of the locomotive, he did not hesitate to declare that locomotive railroads would, before many years had passed, be "the great highways of the world." he urged his views upon the directors in all ways, in season, and, as some of them thought, out of season. he pointed out the greater convenience of locomotive power for the purposes of a public highway, likening it to a series of short unconnected chains, any one of which could be removed and another substituted without interruption to the traffic; whereas the fixed-engine system might be regarded in the light of a continuous chain extending between the two termini, the failure of any link of which would derange the whole. but the fixed engine party was very strong at the board, and, led by mr. cropper, they urged the propriety of forthwith adopting the report of messrs. walker and rastrick. mr. sandars and mr. william rathbone, on the other hand, desired that a fair trial should be given to the locomotive; and they with reason objected to the expenditure of the large capital necessary to construct the proposed engine-houses, with their fixed engines, ropes, and machinery, until they had tested the powers of the locomotive as recommended by their own engineer. george stephenson continued to urge upon them that the locomotive was yet capable of great improvements, if proper inducements were held out to inventors and machinists to make them; and he pledged himself that, if time were given him, he would construct an engine that should satisfy their requirements, and prove itself capable of working heavy loads along the railway with speed, regularity, and safety. at length, influenced by his persistent earnestness not less than by his arguments, the directors, at the suggestion of mr. harrison, determined to offer a prize of £ for the best locomotive engine, which, on a certain day, should be produced on the railway, and perform certain specified conditions in the most satisfactory manner.[ ] the requirements of the directors as to speed were not excessive. all that they asked for was that ten miles an hour should be maintained. perhaps they had in mind the animadversions of the _quarterly review_ on the absurdity of travelling at a greater velocity, and also the remarks published by mr. nicholas wood, whom they selected to be one of the judges of the competition, in conjunction, with mr. rastrick, of stourbridge, and mr. kennedy, of manchester. it was now felt that the fate of railways in a great measure depended upon the issue of this appeal to the mechanical genius of england. when the advertisement of the prize for the best locomotive was published, scientific men began more particularly to direct their attention to the new power which was thus struggling into existence. in the meantime public opinion on the subject of railway working remained suspended, and the progress of the undertaking was watched with intense interest. during the progress of this important controversy with reference to the kind of power to be employed in working the railway, george stephenson was in constant communication with his son robert, who made frequent visits to liverpool for the purpose of assisting his father in the preparation of his reports to the board on the subject. mr. swanwick remembers the vivid interest of the evening discussions which then took place between father and son as to the best mode of increasing the powers and perfecting the mechanism of the locomotive. he wondered at their quick perception and rapid judgment on each other's suggestions; at the mechanical difficulties which they anticipated and provided for in the practical arrangement of the machine; and he speaks of these evenings as most interesting displays of two actively ingenious and able minds stimulating each other to feats of mechanical invention, by which it was ordained that the locomotive engine should become what it now is. these discussions became more frequent, and still more interesting, after the public prize had been offered for the best locomotive by the directors of the railway, and the working plans of the engine which they proposed to construct had to be settled. one of the most important considerations in the new engine was the arrangement of the boiler, and the extension of its heating surface to enable steam enough to be raised rapidly and continuously for the purpose of maintaining high rates of speed--the effect of high pressure engines being ascertained to depend mainly upon the quantity of steam which the boiler can generate, and upon its degree of elasticity when produced. the quantity of steam so generated, it will be obvious, must chiefly depend upon the quantity of fuel consumed in the furnace, and, by necessary consequence, upon the high rate of temperature maintained there. it will be remembered that in stephenson's first killingworth engines he invited and applied the ingenious method of stimulating combustion in the furnace by throwing the waste steam into the chimney after performing its office in the cylinders, thereby accelerating the ascent of the current of air, greatly increasing the draught, and consequently the temperature of the fire. this plan was adopted by him, as we have seen, as early as , and it was so successful that he himself attributed to it the greater economy of the locomotive as compared with horse-power. hence the continuance of its use upon the killingworth railway. though the adoption of the steam blast greatly quickened combustion and contributed to the rapid production of high-pressure steam, the limited amount of heating surface presented to the fire was still felt to be an obstacle to the complete success of the locomotive engine. mr. stephenson endeavoured to overcome this by lengthening the boilers and increasing the surface presented by the flue-tubes. the "lancashire witch," which he built for the bolton and leigh railway, and used in forming the liverpool and manchester railway embankments, was constructed with a double tube, each of which contained a fire, and passed longitudinally through the boiler. but this arrangement necessarily led to a considerable increase in the weight of those engines, which amounted to about twelve tons each; and as six tons was the limit allowed for engines admitted to the liverpool competition, it was clear that the time was come when the killingworth engine must undergo a farther important modification. for many years previous to this period, ingenious mechanics had been engaged in attempting to solve the problem of the best and most economical boiler for the production of high-pressure steam. the use of tubes in boilers for increasing the heating surface had long been known. as early as , matthew boulton employed copper tubes longitudinally in the boiler of the wheal busy engine in cornwall--the fire passing _through_ the tubes--and it was found that the production of steam was thereby considerably increased. the use of tubular boilers afterwards became common in cornwall. in , woolf, the cornish engineer, patented a boiler with tubes, with the same object of increasing the heating surface. the water was _inside_ the tubes, and the fire of the boiler outside. similar expedients were proposed by other inventors. in trevithick invented his light high-pressure boiler for portable purposes, in which, to "expose a large surface to the fire," he constructed the boiler of a number of small perpendicular tubes "opening into a common reservoir at the top." in w. h. james contrived a boiler composed of a series of annular wrought-iron tubes, placed side by side and bolted together, so as to form by their union a long cylindrical boiler, in the centre of which, at the end, the fireplace was situated. the fire played round the tubes, which contained the water. in james neville took out a patent for a boiler with vertical tubes surrounded by the water, through which the heated air of the furnace passed, explaining also in his specification that the tubes might be horizontal or inclined, according to circumstances. mr. goldsworthy, the persevering adaptor of steam-carriages to travelling on common roads, applied the tubular principle in the boiler of his engine, in which the steam was generated _within_ the tubes; while the boiler invented by messrs. summer and ogle for their turnpike-road steam-carriage consisted of a series of tubes placed vertically over the furnace, through which the heated air passed before reaching the chimney. about the same time george stephenson was trying the effect of introducing small tubes in the boilers of his locomotives, with the object of increasing their evaporative power. thus, in , he sent to france two engines constructed at the newcastle works for the lyons and st. etienne railway, in the boilers of which tubes were placed containing water. the heating surface was thus considerably increased; but the expedient was not successful, for the tubes, becoming furred with deposit, shortly burned out and were removed. it was then that m. seguin, the engineer of the railway, pursuing the same idea, is said to have adopted his plan of employing horizontal tubes through which the heated air passed in streamlets, and for which he took out a french patent. in the meantime mr. henry booth, secretary to the liverpool and manchester railway, whose attention had been directed to the subject on the prize being offered for the best locomotive to work that line, proposed the same method, which, unknown to him, matthew boulton had employed but not patented, in , and james neville had patented, but not employed, in ; and it was carried into effect by robert stephenson in the construction of the "rocket," which won the prize at rainhill in october, . the following is mr. booth's account in a letter to the author: "i was in almost daily communication with mr. stephenson at the time, and i was not aware that he had any intention of competing for the prize till i communicated to him my scheme of a multitubular boiler. this new plan of boiler comprised the introduction of numerous small tubes, two or three inches in diameter, and less than one-eighth of an inch thick, through which to carry the fire instead of a single tube or flue eighteen inches in diameter, and about half an inch thick, by which plan we not only obtain a very much larger heating surface, but the heating surface is much more effective, as there intervenes between the fire and the water only a thin sheet of copper or brass, not an eighth of an inch thick, instead of a plate of iron of four times the substance, as well as an inferior conductor of heat. "when the conditions of trial were published, i communicated my multitubular plan to mr. stephenson, and proposed to him that we should jointly construct an engine and compete for the prize. mr. stephenson approved the plan, and agreed to my proposal. he settled the mode in which the fire-box and tubes were to be mutually arranged and connected, and the engine was constructed at the works of messrs. robert stephenson & co., newcastle-on-tyne. "i am ignorant of m. seguin's proceedings in france, but i claim to be the inventor in england, and feel warranted in stating, without reservation, that until i named my plan to mr. stephenson, with a view to compete for the prize at rainhill, it had not been tried, and was not known in this country." from the well-known high character of mr. booth, we believe his statement to be made in perfect good faith, and that he was as much in ignorance of the plan patented by neville as he was of that of seguin. as we have seen, from the many plans of tubular boilers invented during the preceding thirty years, the idea was not by any means new; and we believe mr. booth to be entitled to the merit of inventing the method by which the multitubular principle was so effectually applied in the construction of the famous "rocket" engine. the principal circumstances connected with the construction of the "rocket," as described by robert stephenson to the author, may be briefly stated. the tubular principle was adopted in a more complete manner than had yet been attempted. twenty-five copper tubes, each three inches in diameter, extended from one end of the boiler to the other, the heated air passing through them on its way to the chimney; and the tubes being surrounded by the water of the boiler, it will be obvious that a large extension of the heating surface was thus effectually secured. the principal difficulty was in fitting the copper tubes in the boiler ends so as to prevent leakage. they were manufactured by a newcastle coppersmith, and soldered to brass screws which were screwed into the boiler ends, standing out in great knobs. when the tubes were thus fitted, and the boiler was filled with water, hydraulic pressure was applied; but the water squirted out at every joint, and the factory floor was soon flooded. robert went home in despair; and in the first moment of grief he wrote to his father that the whole thing was a failure. by return of post came a letter from his father, telling him that despair was not to be thought of--that he must "try again;" and he suggested a mode of overcoming the difficulty, which his son had already anticipated and proceeded to adopt. it was, to bore clean holes in the boiler ends, fit in the smooth copper tubes as tightly as possible, solder up, and then raise the steam. this plan succeeded perfectly, the expansion of the copper tubes completely filling up all interstices, and producing a perfectly water-tight boiler, capable of withstanding extreme external pressure. the mode of employing the steam-blast for the purpose of increasing the draught in the chimney was also the subject of numerous experiments. when the engine was first tried, it was thought that the blast in the chimney was not sufficiently strong for the purpose of keeping up the intensity of fire in the furnace, so as to produce high-pressure steam with the required velocity. the expedient was therefore adopted of hammering the copper tubes at the point at which they entered the chimney, whereby the blast was considerably sharpened; and on a farther trial it was found that the draught was increased to such an extent as to enable abundance of steam to be raised. the rationale of the blast may be simply explained by referring to the effect of contracting the pipe of a water-hose, by which the force of the jet of water is proportionately increased. widen the nozzle of the pipe, and the jet is in like manner diminished. so it is with the steam-blast in the chimney of the locomotive. doubts were, however, expressed whether the greater draught obtained by the contraction of the blast-pipe was not counterbalanced in some degree by the negative pressure upon the piston. hence a series of experiments was made with pipes of different diameters, and their efficiency was tested by the amount of vacuum that was produced in the smoke-box. the degree of rarefaction was determined by a glass tube fixed to the bottom of the smoke-box and descending into a bucket of water, the tube being open at both ends. as the rarefaction took place, the water would, of course, rise in the tube, and the height to which it rose above the surface of the water in the bucket was made the measure of the amount of rarefaction. these experiments proved that a considerable increase of draught was obtained by the contraction of the orifice; accordingly, the two blast-pipes opening from the cylinders into either side of the "rocket" chimney, and turned up within it, were contracted slightly below the area of the steam-ports, and before the engine left the factory, the water rose in the glass tube three inches above the water in the bucket. the other arrangements of the "rocket" were briefly these: the boiler was cylindrical, with flat ends, six feet in length, and three feet four inches in diameter. the upper half of the boiler was used as a reservoir for the steam, the lower half being filled with water. through the lower part the copper tubes extended, being open to the fire-box at one end, and to the chimney at the other. the fire-box, or furnace, two feet wide and three feet high, was attached immediately behind the boiler, and was also surrounded with water. the cylinders of the engine were placed on each side of the boiler, in an oblique position, one end being nearly level with the top of the boiler at its after end, and the other pointing toward the centre of the foremost or driving pair of wheels, with which the connection was directly made from the piston-rod to a pin on the outside of the wheel. the engine, together with its load of water, weighed only four tons and a quarter; and it was supported on four wheels, not coupled. the tender was four-wheeled, and similar in shape to a waggon--the foremost part holding the fuel, and the hind part a water cask. when the "rocket" was finished it was placed upon the killingworth railway for the purpose of experiment. the new boiler arrangement was found perfectly successful. the steam was raised rapidly and continuously, and in a quantity which then appeared marvellous. the same evening robert despatched a letter to his father at liverpool, informing him, to his great joy, that the "rocket" was "all right," and would be in complete working trim by the day of trial. the engine was shortly after sent by waggon to carlisle, and thence shipped for liverpool. the time so much longed for by george stephenson had now arrived, when the merits of the passenger locomotive were about to be put to the test. he had fought the battle for it until now almost single-handed. engrossed by his daily labours and anxieties, and harassed by difficulties and discouragements which would have crushed the spirit of a less resolute man, he had held firmly to his purpose through good and through evil report. the hostility which he experienced from some of the directors opposed to the adoption of the locomotive was the circumstance that caused him the greatest grief of all; for where he had looked for encouragement, he found only carping and opposition. but his pluck never failed him; and now the "rocket" was upon the ground to prove, to use his own words, "whether he was a man of his word or not." on the day appointed for the great competition of locomotives at rainhill the following engines were entered for the prize: . messrs. braithwaite and ericsson's "novelty." . mr. timothy hackworth's "sanspareil." . messrs. r. stephenson & co.'s "rocket." . mr. burstall's "perseverance." the ground on which the engines were to be tried was a level piece of railroad, about two miles in length. each was required to make twenty trips, or equal to a journey of seventy miles, in the course of the day, and the average rate of travelling was to be not under ten miles an hour. it was determined that, to avoid confusion, each engine should be tried separately, and on different days. the day fixed for the competition was the st of october, but, to allow sufficient time to get the locomotives into good working order, the directors extended it to the th. it was quite characteristic of the stephensons that, although their engine did not stand first on the list for trial, it was the first that was ready, and it was accordingly ordered out by the judges for an experimental trip. yet the "rocket" was by no means the "favourite" with either the judges or the spectators. nicholas wood has since stated that the majority of the judges were strongly predisposed in favour of the "novelty," and that "nine-tenths, if not ten-tenths, of the persons present were against the "rocket" because of its appearance." nearly every person favoured some other engine, so that there was nothing for the "rocket" but the practical test. the first trip made by it was quite successful. it ran about twelve miles, without interruption, in about fifty-three minutes. the "novelty" was next called out. it was a light engine, very compact in appearance, carrying the water and fuel upon the same wheels as the engine. the weight of the whole was only three tons and one hundred-weight. a peculiarity of this engine was that the air was driven or _forced_ through the fire by means of bellows. the day being now far advanced, and some dispute having arisen as to the method of assigning the proper load for the "novelty," no particular experiment was made further than that the engine traversed the line by way of exhibition, occasionally moving at the rate of twenty-four miles an hour. the "sanspareil," constructed by mr. timothy hackworth, was next exhibited, but no particular experiment was made with it on this day. this engine differed but little in its construction from the locomotive last supplied by the stephensons to the stockton and darlington railway, of which mr. hackworth was the locomotive foreman. the contest was postponed until the following day; but, before the judges arrived on the ground, the bellows for creating the blast in the "novelty" gave way, and it was found incapable of going through its performance. a defect was also detected in the boiler of the "sanspareil," and some further time was allowed to get it repaired. the large number of spectators who had assembled to witness the contest were greatly disappointed at this postponement; but, to lessen it, stephenson again brought out the "rocket," and, attaching it to a coach containing thirty persons, he ran them along the line at a rate of from twenty-four to thirty miles an hour, much to their gratification and amazement. before separating, the judges ordered the engine to be in readiness by eight o'clock on the following morning, to go through its definite trial according to the prescribed conditions. on the morning of the th of october the "rocket" was again ready for the contest. the engine was taken to the extremity of the stage, the fire-box was filled with coke, the fire lighted, and the steam raised until it lifted the safety-valve loaded to a pressure of fifty pounds to the square inch. this proceeding occupied fifty-seven minutes. the engine then started on its journey, dragging after it about thirteen tons' weight in waggons, and made the first ten trips backward and forward along two miles of road, running the thirty-five miles, including stoppages, in an hour and forty-eight minutes. the second ten trips were in like manner performed in two hours and three minutes. the maximum velocity attained during the trial trip was twenty-nine miles an hour, or about three times the speed that one of the judges of the competition had declared to be the limit of possibility. the average speed at which the whole of the journeys was performed was fifteen miles an hour, or five miles beyond the rate specified in the conditions published by the company. the entire performance excited the greatest astonishment among the assembled spectators; the directors felt confident that their enterprise was now on the eve of success; and george stephenson rejoiced to think that, in spite of all false prophets and fickle counsellors, the locomotive system was now safe. when the "rocket," having performed all the conditions of the contest, arrived at the "grand stand" at the close of its day's successful run, mr. cropper--one of the directors favourable to the fixed engine system--lifted up his hands, and exclaimed, "now has george stephenson at last delivered himself...." the "rocket" had eclipsed the performance of all locomotive engines that had yet been constructed, and outstripped even the sanguine expectations of its constructors. it satisfactorily answered the report of messrs. walker and rastrick, and established the efficiency of the locomotive for working the liverpool and manchester railway, and, indeed, all future railways. the "rocket" showed that a new power had been born into the world, full of activity and strength, with boundless capability of work. it was the simple but admirable contrivance of the steam-blast, and its combination with the multitubular boiler, that at once gave locomotion a vigorous life, and secured the triumph of the railway system.[ ] [illustration: the "rocket"] footnotes: [ ] the conditions were these: . the engine must effectually consume its own smoke. . the engine, if of six tons' weight, must be able to draw after it, day by day, twenty tons' weight (including the tender and water-tank) at _ten miles_ an hour, with a pressure of steam on the boiler not exceeding fifty pounds to the square inch. . the boiler must have two safety-valves, neither of which must be fastened down, and one of them be completely out of the control of the engine-man. . the engine and boiler must be supported on springs, and rest on six wheels, the height of the whole not exceeding fifteen feet to the top of the chimney. . the engine, with water, must not weigh more than six tons; but an engine of less weight would be preferred on its drawing a proportionate load behind it; if of only four and a half tons, then it might be put on only four wheels. the company will be at liberty to test the boiler, etc., by a pressure of one hundred and fifty pounds to the square inch. . a mercurial gauge must be affixed to the machine, showing the steam pressure above forty-five pounds per square inch. . the engine must be delivered, complete and ready for trial, at the liverpool end of the railway, not later than the st of october, . . the price of the engine must not exceed £ . many persons of influence declared the conditions published by the directors of the railway chimerical in the extreme. one gentleman of some eminence in liverpool, mr. p. ewart, who afterward filled the office of government inspector of post-office steam packets, declared that only a parcel of charlatans would ever have issued such a set of conditions; that it had been _proved_ to be impossible to make a locomotive engine go at ten miles an hour; but if it ever was done, he would undertake to eat a stewed engine-wheel for his breakfast. [ ] when heavier and more powerful engines were brought upon the road, the old "rocket," becoming regarded as a thing of no value, was sold in . it has since been transferred to the museum of patents at south kensington, london, where it is still to be seen. transcriber's notes: page --imployed changed to employed. page --subsequenty changed to subsequently. page --build changed to building. page --suggestor changed to suggester. page --supgestion changed to suggestion. footnote --changed question mark for a period. inconsistencies in hyphenated words have been made consistent. obvious printer errors, including punctuation, have been corrected without note. produced from scanned images of public domain material from the google print project.) united states patent office the classification of patents [illustration: department of the interior] washington government printing office prefatory note. parts a and b of the following pages are designed to acquaint all persons using the patent office classification with the principles upon which the reclassification is proceeding. part c consists of a few tentative rules advanced with the notion of fixing classification practice within the office in certain doubtful cases. part d is intended to inform examiners reclassifying within examining divisions respecting the initial procedure in reforming a class. contents. page. a. introduction. past classifications of the u. s. patent office. beginning of revision. precedents and authorities. definition of scientific classification. b. principles of the new classification of the patent office. elements of a patent office classification. basis of classification. art as a basis. function or effect as a basis. structure as a basis. division and arrangement. infinitude of possible combinations. division and arrangement in the natural sciences. difficulty of entitling a subclass corresponding to every combination. expedients to reduce the number of subdivisions. superiority and inferiority. definite positional relationship of subdivisions. indented schedules. bifurcate division. utility of arrangement according to resemblances. definition. cross-references and search-notes. diagnosis to determine classification. claimed or unclaimed disclosure. diagnosis of pending applications. difficulties due to varying ideas of claims. c. rules of classification. basis of classification. . "art" as the basis. . operative or manipulative arts. . structures. . composition of matter and formed stock. division and arrangement. . exhaustive division; miscellaneous subclass. . subclasses not to overlap. . subclasses of any group to be formed on one basis. . apparent exception to rules and . . relative position of subclasses. . indention of subclasses. . different kinds of titles for subclasses. . arrangement to limit search and cross references. definition. . tentative definition. . how to define. . explanatory notes may sometimes displace definition. cross-references and search-notes. . impossibility of cross-referencing all disclosures. . occasion and direction of cross-referencing. . occasion and scope of search-notes. diagnosis to determine classification. . patents diagnosed by claimed disclosure. . patents diagnosed by most intensive claim. . exception to rule , claim, for a part of a disclosed combination. . exception to rule , claims for a part of a disclosed combination. . exception to rule , generic combination old as matter of common knowledge. . exception to rule , article of manufacture defined only by material. . exception to rule , utilizing a composition. . exception to rule , utilizing a machine. . patents having claims for several different inventions. . general rule of superiority between statutory kinds of invention. . exception to rule . . process and apparatus. . article of manufacture and instrument for making a part of it or performing any minor act relative thereto. . process and product where search for the process would have to be made among machines. . process and product where search for the process would have to be made among products. . process of making a composition and the composition where the process is peculiarly adapted to make the composition. . article of manufacture or composition and process for making one of the parts of the article or ingredients of the composition. d. procedure in reclassifying within examining divisions. . general attitude. procedure involving only cursory scrutiny of familiar patents-- . consider wholes in forming tentative subdivisions of subclasses. . write tentative definitions of subdivisions. . consider the significance of analogies found to traverse parts of two or more existing subclasses. . arrange groups on parallel or accordant lines where practicable. . watch for subcombinations deserving separate recognition. . consider whether the groups collectively will constitute a proper class and their best correlation. procedure involving rigorous analysis-- . diagnose each patent for original classification. . group and consider the disposition of patents deemed foreign to the class. - . consider and indicate cross-referencing within and to and from the class. , note. the classification of patents (a) introduction. classification lies at the foundation of the mental processes. without the power of perceiving, recognizing resemblances, distinguishing differences in things, phenomena and notions, grouping them mentally according to those resemblances and differences, judgment is impossible, nor could reason be exercised in proceeding from the known to the unknown. * * * * * the facilitation and abbreviation of mental labor is at the bottom of all mental progress. the reasoning faculties of newton were not different in qualitative character from those of a ploughman; the difference lay in the extent to which they were exerted and the number of facts which could be treated. every thinking being generalizes more or less, but it is the depth and extent of his generalizations which distinguish the philosopher. now it is the exertion of the classifying and generalizing powers which thus enables the intellect of man to cope in some degree with the infinite number and variety of natural phenomena and objects. (jevons, principles of science.) past classifications of united states patent office. as under the patent laws the people of the united states assume all the risks in granting a patent for any means of the "useful arts," a classification that will facilitate a judgment respecting the patentability of any means presented to the patent office is of peculiar moment. the enormous extent, diversity, and refinement of the useful arts preclude the formation of a judgment on novelty within a reasonable time, unless the necessary comparisons with known processes and instruments have been previously made along the lines that searches must follow and the results of such comparisons made available in a classification. the vast majority of available disclosures of the arts occur in patents. hence the patent office classification must be adjusted in the main to the analysis, diagnosis, and orderly arrangement of the disclosures of patents. for more than years united states patents have been classified. the first published classification, promulgated in , comprised , patents, divided into classes. the change from a registration to an examination system in instigated a new classification in classes, including , patents. the next came in with classes, including about , patents. on march , , a revised classification was adopted, comprising classes, including , patents. this classification is said to have been planned by dr. edward h. knight. the placing of the patents in accordance with the schedule of classes is said to have been done by the several examiners. the class arrangement was purely alphabetical by class titles, and the number designations followed the alphabetical order. the names of things to be found in the several classes were arranged alphabetically under each class title. no attempt was made to bring the titles of allied materials into juxtaposition or to effect other definite arrangement with reference to subject matter in the printed schedules. a consolidated name index supplemented the list of names by classes. this classification of is in part the classification that now exists, many of the same class numbers and titles being still in use. examiners were apparently permitted to make changes in classification to suit their convenience without notice until . in that year a revision of the published schedule was made by a committee, resulting in the addition of new classes, and examiners were ordered to transfer patents in accordance with the new titles. the first classification published with distinct subclasses appeared in . from that time until the classification grew by addition and subdivision of classes to suit the ends of individual examiners or in response to supposed exigencies of the work where one division was thought to be overloaded and another underloaded, and the alphabetical arrangement of subclasses under each class has succeeded the alphabetical list of names. the arbitrary correspondence originally established between the alphabetical order of class titles and the numerical order was destroyed as soon as expansion of the classification began. however suitable to the then-existing material of the useful arts the classification of may have been, it failed as fail all inductive processes wherein the generalizations are not broad and deep. (isaac newton's intellect could detect the resemblance between the falling fruit and the motions of the planets.) the classification of was not exhaustive; it failed to recognize to the fullest extent what bishop wilkins saw nearly years ago, to wit, that there are "arts of arts;" and it failed to provide for future invention of new species in the same art, and to recognize that new arts could be formed from combinations of the old. beginning of revision. the classification division was created in the hope that guiding principles of classification could be developed and applied for the purpose of amending or revising the classification whereby patents could be placed with greater assurance, and whereby the searcher with these guiding principles in mind might find the nearest references. it was confronted with the problem of revising while at the same time keeping accurate record of all changes, correcting all indexes of patents, and using copies in constant demand for search at the same time, necessitating much clerical work, and constant interruption--of correcting rather than planning anew; of mending a machine while constantly increasing duty was required of it. ideas on the subject of revision were called for by the commissioner of patents, and all in the patent office had an opportunity to set forth their notions. the views of one met with approval and in accordance with those views a "plan of classification" was prepared and promulgated in . what other plans may have been submitted is not now generally known. but in substantial accordance with that published plan, the process of revision has proceeded for more than years until approximately per cent of the patents (including incomplete work) have been placed in revised classes. precedents and authorities. no effective precedents have been found in any prior classifications of the arts. the classifications of the principal foreign patent offices have not been materially different in principle from the united states patent office classifications of the past. the divisions found suitable for book classification for library use, have not been deemed adequate to the exactness and refinement essential to a patent office classification of the useful arts. the systems of class and subclass sign or number designations of the modern library classifications, with their mnemonic significance, afford the most important suggestions to be drawn from library classification. none of these systems of designation has been adopted, ( ) because of a serious doubt as to the availability of such designations by reason of the length or unwieldiness to which they would attain in the refinements of division necessary in a patent office classification, and ( ) because of the enormous amount of labor necessary to make the change from present practice. the best analogies are in the known (but changing) classifications of the natural sciences, and in them the problems are so different that they can serve only to illustrate general principles. the broad principles of classification are well understood. the authorities are the logicians from the ancient aristotle to the modern bentham, mill, and jevons. the effort of the classification division has been to adapt and apply these well-known principles to the enormously diversified useful arts, particularly as disclosed in patents and applications for patents. definition of scientific classification. it may be well to insert here an authoritative definition: "a scientific classification is a series of divisions so arranged as best to facilitate the complete and separate study of the several groups which are the result of the divisions as well as of the entire subject under investigation." (fowler, inductive logic.) investigation and study of any subject will be facilitated if the facts or materials pertinent to that subject be so marshaled and arranged that those most pertinent to it may appear to the mind in some form of juxtaposition. it is the purpose of the patent office classification to divide and arrange the body and multitudinous units of the useful arts so that, having the question of novelty of any defined means to answer, one may with reasonable assurance approach that portion of the rank of arts in which it will be found if it is not new, and in propinquity to which will also be found those means that bear the closest resemblances to that sought for, the resemblances of other units growing less in proportion to their distance therefrom. success in the fundamental aim of facilitating adequate search should evidently at the same time reduce proportionately the danger that interfering applications will be overlooked and also effect a distribution of labor favorable to the acquisition of special skill. (b) principles of the new classification of the patent office. the elements of a patent office classification. a classification will be useful in proportion ( ) to the pertinence to the subject under investigation of the facts selected to be grouped together, or, in other words, in proportion to the appropriateness of the "basis of classification" to the subject in hand; ( ) to the convenience, stability, and uniformity of the arrangement of the subdivisions whereby the investigator may proceed with reasonable assurance to that portion of the rank of groups within which he will find cognate material; ( ) to the accuracy and perspicuity of the definitions of the several divisions and subdivisions; ( ) to the completeness and reliability of the cross-referencing and cross-notations; ( ) to the uniformity, feasibility, and certainty of the rules by which the accessions of patents disclosing one or several inventions may be diagnosed and distributed to the appropriate divisions of the classification in accordance with the basis adopted. corresponding to the foregoing analysis the theory of patent office classification may be treated in five parts: ( ) the principles on which the arts shall be divided (basis of classification); ( ) subdivision and mechanical arrangement of groups; ( ) definition; ( ) cross-referencing and search-notes; ( ) the choice of features by which a patent shall be assigned in the classification (diagnosis). basis of classification. the first and most vital factor in any system of classification is the basis of division, that is, the kind of characteristics common to any number of objects selected to characterize groups, whereby the individuals of any group will resemble each other for the purpose in view more closely than any individual in any group will resemble any individual in any other group. "there is no property of objects which may not be taken, if we please, as the foundation for a classification or mental grouping of those objects, and in our first attempts we are likely to select for that purpose properties which are simple, easily conceived, and perceptible in a first view without any previous process of thought--but these classifications are seldom much adapted to the ends of that classification which is the subject of our present remarks." (j. s. mill, system of logic.) it is clear that a number of objects may be classified on several different bases. for example, a number of books could be divided into groups ( ) according to the subject of their contents; ( ) according to the language in which the books are written; ( ) according to the size of page; ( ) according to the binding material; or ( ) according to the color of the binding. each of these may be useful classifications for some purpose. for the student of literature none is of value except the first; for the connoisseur in bindings, only the last three. a classification of animals including classes of land animals and water animals would hardly suit a student of zoology, as it would associate with the shad and perch such differently organized creatures as the porpoise, whale, and seal. yet such a classification might prove very suitable for a student of fisheries. _art as a basis._[ ]--so in seeking a basis for a patent office classification the purposes of the classification should be the guide. allegations of ulterior uses[ ] (such as may be made merely because the inventor thought of applying his invention to those uses only, or in an effort to get the application examined in a certain division) and other superficial bases should be avoided. that basis will best suit the purpose which effects such an arrangement as will exhibit in suitable groups the "state of the prior art," by which is here meant not necessarily all the instruments of a trade or industry, or all the articles sold by a shopkeeper, as a stationer, but those means that achieve similar results by the application of similar natural laws[ ] to similar substances. as all inventions are made with the ultimate object of satisfying some human desire, the utility of an invention appears to be a natural basis of classification. it is apparent, however, that most inventions may contribute to numerous utilities besides the ultimate one. many processes and instruments intervene between the seed planter and the wheaten rolls upon the breakfast table. the plow may be viewed as an agricultural instrument or as an instrument of civil engineering, according as it is used for preparing the field for planting or rounding a road. a radiating coil of pipe may be thought of as a condenser of steam or of alcoholic vapors, according as it is applied to one material or another; as a cooler or a heater, according to the temperature of a fluid circulated through it. a hammer may drive nails, forge iron, crack stone or nuts. underlying all of these ulterior utilities, there is a fundamental one to which the normal mind will reach in its natural processes and there rest. the plow loosens or turns over the surface of earth; the coil effects an exchange of heat between its interior and exterior; the hammer strikes a blow. a classification of plows in agriculture, road building, or excavating, according to stated ultimate use; of a radiator coil as a steam condenser, still, jacket-water cooler, refrigerator, or house heater; of the hammer as a forging tool, a nail driver, or a nut cracker, appears to separate things that are essentially alike. but classifying a plow on its necessary function of plowing, a radiator on its necessary function of exchanging heat, a hammer on its necessary function of striking a blow, evidently results in getting very similar things together. assuming for the moment that utility is a reasonable basis of division of the useful arts, it is deemed more logical to adopt as a basis some utility that _must_ be effected by the means under consideration when put to its normal use rather than some utility that _may_ be effected under _some_ conditions. two of the five predictables of ancient logic are property[ ] and accident.[ ] the capacity of the hammer to strike a blow, the capacity of the radiator coil to exchange heat, are in the nature of properties. the capacity of the hammer to crack nuts, of the coil to condense steam, are in the nature of accidents--something that follows from the impact and the heat exchange because of the particular accidental conditions of operation. to select an accident as a basis of classification is contrary to the laws of thought. it may be said then that the patent office classification is based upon "art" in the strict sense in which the word may be said to be used in section , revised statutes, but not necessarily in the looser sense of industries and trades. a proper maintenance of the distinction between the word "arts" of the statute and the phrase "industrial arts" used in the sense of industries and trades is essential to an effective classification for the purposes of a patent office search. similar instruments have been patented in three different classes, because of the statements that one was designed for cooling water, another for heating water, another for sterilizing milk; in four different classes, because of the statements that one apparatus was to separate solids from the gases discharged from a metallurgical furnace, another to separate carbon from the combustion gases of a steam-boiler furnace, another to remove dust and tar from combustible gas, and another to saturate water with carbon dioxid. owing to the continuance of a classification based largely on remote use, many applications come into the office setting forth inventions of very general application which nevertheless have to be classified more or less arbitrarily in one of several arts in which they may be used but to which they are not limited. _function or effect as a basis._[ ]--means of the useful arts are related in different degrees. resemblances selected as bonds for a number of inventions may be more or less close. it is axiomatic that close resemblances should be preferred over looser ones for classification purposes. processes and instruments for performing general operations, such as moving, cutting, molding, heating, treating liquids with gases, assembling, etc., are more closely bonded than those for effecting the diverse separate successive operations directed toward complex special results, such as making shoes, buttons, nails, etc. means of the former sort perform an essentially unitary act--the application of a single force, the taking advantage of a single property of matter. those of the latter sort require the application of several different acts employing frequently a plurality of forces or taking advantage of several properties of matter. in the former case, classification can be based on what has been called function, in the latter it cannot be based on function but can be based on what has been called effect (or product). function is closely related to cause. it is an axiom of logic that cause is preferable to effect as a basis of those classifications designed for scientific research. hence the functional basis is preferred in all cases in which it can be applied. a condenser for the fumes of zinc is much more like a condenser for the fumes of acid or the vapor of water than it is like the art of recovering zinc from its ores, and it employs only one principle, to wit, heat interchange. a water-jacket for cooling the walls of a gas-producer or glass-furnace is much more like a water-jacket for cooling the walls of a limekiln or steam-boiler furnace than it is like the art of gas-making or manufacture of glass articles. in accordance with what are thought to be the correct principles, therefore, the zinc-condenser ought not to be classified as a part of the art of metallurgy, nor the water-jacket as a part of the art of gas-making, merely because these instruments have a use in these arts, but should be included, respectively, in classes based upon the more fundamental utilities effected by them. although it is evident that molding a button is more like molding a door-knob than it is like making buttons by the combined operations of sawing, grinding, turning, and drilling, wherefore the molding of buttons should be classified in a general plastic art rather than in a special button-making art, yet the making of buttons by a plurality of different kinds of operations can be placed only in a class based upon the product, to wit, button-making. since, therefore, the combination of many different operations for the production of a specific article can not be classified on the basis of any single function, it must be classified on the basis of product. thus by selecting essential function as a basis when possible, and resulting effect when the functional basis is not possible, one may approximate to the correct classification described by herbert spencer as follows: "a true classification includes in each class those objects that have more characteristics in common with one another than any of them have with objects excluded from the class."[ ] so it is deemed better to classify in accordance with the function or effect it is known a means _must_ perform or accomplish than in accordance with the _object_ with respect to which an act or acts are directed or in accordance with some _effect_ which may or may not result. _structure as a basis._--the phrase "structural classification" is frequently made use of. the application of the phrase to processes is manifestly absurd. the patent office never had a structural classification except in a limited sense. how could a machine, for example, be classified on structure, leaving out of consideration its function and the effect of its normal operation? in the refinements of subdivision however, it becomes frequently desirable to form minor subdivisions on structural differences. and it may also be that instruments will be presented for classification that are of such general utility as to baffle the efforts of the intellect to attain to the fundamental and necessary function, in which case a structure-defined class may best suit the needs of classification. as between a classification based upon structure and one based upon utility, the choice has been for the latter, without prejudice, however, to instances that may arise in favor of the former. the subject of structural classification will be dropped with a quotation from the original pamphlet "plan of classification," etc. (p. ): "a purely 'structural' classification is almost impossible on account of the infinite variety of mechanical combinations, and to attempt it would probably result in utter confusion, for the classes could not be defined, and the classification would be a mere digest of mechanical elements having no community of function." division and arrangement. having divided the aggregate of things to be classified into a large number of groups on a satisfactory basis, a most useful work will have been accomplished and the purpose of a classification to assemble the things most nearly alike and separate them from other things will have been partially achieved. unless these numerous groups are arranged in some definite understandable relation to each other, or are placed in definite known positions where they can be found, the mere formation of the groups, on however good a basis, is not a complete classification. furthermore, unless the position of each group with respect to those other groups that resemble it in whole or in part is made known, he who wishes to find other related matter must seek aimlessly with no assurance that his quest will end until the whole series shall have been investigated. each classified group is metaphorically a pigeonhole to contain similar material. if the pigeonholes are properly labeled, one can ultimately locate those that contain the matter he is seeking if he knows the name that has been applied to it. if the pigeonholes are arranged in alphabetical order, for example, he may find all related material, _provided he knows the name of every related group of material_, even though very similar things may bear names as far apart as a and z. but if all things were so placed that, adjacent and in certain fixed relation to each pigeonhole, other related matter could be found, the resemblances lessening in proportion to the separation, and if the entire area of pigeonholes were divided, and certain areas assigned to certain kinds of things defined in general terms, guessing the location of and desultory search for things that may have different names, but yet be very much alike, would be lessened and all cognate material be bunched. a second vital factor of a system of classification, therefore, is the arrangement of the groups. _infinitude of possible combinations._--there are now over , , united states patents, each presumptively covering a creation of the useful arts that is different from every other. most of these patents also disclose a plurality of elements or acts. each of these patented means is potentially an element of a more complex combination that may be patented. when one considers merely the number of forms of energy, the number of known substances and known mechanical elements, and attempts to figure possible combinations and permutations, it becomes apparent that the size of the numbers resulting is incomprehensible. consider the possibilities of combination also of the enormously varied disclosures of patents. calculations of the possible combinations and permutations of a small number of objects are familiar. different combinations of the letters of the alphabet are sufficient to record the sum of human knowledge in many languages. with substantially two octaves of the diatonic scale the world's melodies have been sounded, nor do any doubt that our successors will thrill to airs that we have never heard. "thirty metals may be combined into binary alloys, , ternary alloys, , quaternary alloys" (jevons). this does not take into consideration differences in proportion that figure so largely in results in the arts of substance-making. the total number of possible alloys of the known metals is incomprehensible. a moment's thought respecting the numbers of the means of the useful arts will alleviate any fears that the possibilities of invention are near the limit and will give food for further thought to all concerned with this attempt to classify the useful arts to the point of refinement necessary to enable this office to pass judgment with reasonable speed and accuracy upon the approximately , applications filed each year. _division and arrangement in the natural sciences._--some of the natural sciences are said to be in what is known as the classificatory stage of development. in some sciences the subject of classification has been predominant and these furnish excellent examples of scientific classification. the much-admired classifications of zoology, botany, and mineralogy are among the best available models of logical division,[ ] systematic and analytical arrangement. the most casual consideration of these classifications, however, renders apparent the relative simplicity of the task of classifying natural objects differentiated by fixed natural laws as compared with the task of classifying the products of the creative and imaginative faculties as applied to the useful arts. the chimera and other animal monsters occur only as figments of the mind. zoological classification does not have to classify combinations of birds, fishes, reptiles, and mammals, nor does it deal in the way of classification with the parts of animals, nor is the question of absolute numbers of instances a matter of moment to such a classification, all of the members of a species being alike for classification purposes. but any instrument of the useful arts may be combined with some other, any part with some other part. organizations may be parts of some other organizations, or even mutually parts of each other, as, for example, a pump may be a part of a lubricator, or a lubricator may be a part of a pump. some parts are peculiar to one instrument, some are common to many. every member of a species differs from every other member. added to this, the intellectual differences between the persons who present the applications for patent, the differences in their generalizing powers, the relatively broad and narrow views of two or more persons presenting the same invention (variations not indulged in by nature) complicate the problem of classifying the useful arts. _difficulty of entitling a subclass corresponding to every combination._--in any main class or group of the useful arts there are always a number of characteristics that it may be desirable to take note of in subdivision titles. a moment's thought shows the impossibility of taking care of any large number of combined characteristics so as to provide exactly for each combination, for the reason that the limitations of space and of the perceptive faculties forbid. for a simple illustration, the imaginary classification of books for use by a bookseller may be recurred to. the dealer, it may be assumed, has books on ( ) four different subjects, history, science, art, and fiction, ( ) each printed in four languages, english, german, french, spanish, ( ) in four different sizes of page, folio, quarto, octavo, duodecimo, ( ) bound in four materials, leather, rawhide, cloth, paper. here are four main characteristics, each in four varieties. a customer is likely to ask for ivanhoe in english, octavo, bound in leather. now if the bookseller had sought to arrange the books into one class according to subject matter, into another according to language, another according to size, another according to binding, he would have fallen into confusion, because his classes would be formed on different principles or bases and overlap. some histories will be in french, some will have octavo pages, and some cloth bindings. but if he divides first on the basis of subject matter, then each subject matter into language, each language book into sizes, each size into material of binding, he can immediately place his hand on a class wherein the book will be if he has it; but this classification, based on four different characteristics and four varieties of each, has necessitated the formation of classes or divisions, and if five characteristics were provided for, , divisions would be required. adapting the illustration of the books to a patent office classification: if it were possible to view these characteristics as patentable in combinations of all or in any combinations less than all, and also as separate characteristics, divisions additional to the for each independent characteristic would have to be provided, as well as other divisions for combinations of less than the whole, in order to make the classification absolutely indicative of every feature, and the number of divisions would be enormous. in such a classification, after the proper division had been located, the search would be nothing, the difficulty would be to find the appropriate class. _expedients to reduce the number of subdivisions._--fortunately most people carry on their mental processes in accordance with certain uniformities. under this uniformity of thought no patentable relationship may be alleged between a quarto volume and the subject of history or between a leather binding and the german language; wherefore classes of coordinate value, based on the characteristics, each divided into subclasses, divisions in all, may serve the purpose of a patent office search. but if, as sometimes happens, a patentable relationship had been assumed and admitted between a leather binding and any of the languages, or any of the subjects, or between any two or more of those different characteristics, provision could be made for such combinations by the following expedients: ( ) arrange the characteristics, in the order of relative significance or importance for the purpose in view, in four groups, giving each group the characteristic title. under each title arrange the varieties in a similar relation as follows in either ( ) or ( ): ( ) ( ) cl. x.--books. cl. x.--books. . miscellaneous. . subject-matter-- . subject-matter-- . history. . history. . science. . science. . art. . art. . fiction. . fiction-- . language-- . language-- . english. . english. . german. . german. . french. . french. . spanish. . spanish. . size-- . size-- . folio. . folio. . quarto. . quarto. . octavo. . octavo. . duodecimo. . duodecimo. . binding-- . binding material-- . leather. . leather. . rawhide. . rawhide. . cloth. . cloth. . paper. . paper. subject-matter, assumed to be the most important characteristic, is placed first. any exhibit of mere material for binding, mere size, mere language, or mere subject-matter, would fall into the correspondingly entitled group. if, however, a book on history in german or a history in red leather, etc., were to be classified, it would be placed in subclass "history" in the subject-matter group, and a french book in green cloth would be placed in subclass "french" in the language group. that is, combinations of any characteristic with any one or more other characteristics may be placed in the group for that characteristic deemed the most significant and which is highest in the schedule. again, by assigning a number to each generic title, each such title becomes thereby the miscellaneous group for varieties other than those indented under it, as well as for all varieties associating any characteristic with one or more of those standing lower down. thus, a book of poems would belong in subclass "subject-matter" and a mo volume bound with purple celluloid covers would belong in subclass "size." so, by giving meaning to relative position, exhaustive arrangement is sought to be provided in a reasonable number of groups. to provide for other features that may be presented in future, an additional miscellaneous group may be added at the top ( ), or the class title ( ) might be deemed to represent the unclassified residue and a depository for future matter not specifically provided for. ( ) if the number of instances of association of subject-matter and binding materials, language and size, etc., are numerous, additional groups might be placed above the groups having the names of the characteristics, the fact of the existence of these groups indicating that the characteristic groups are for single characteristics only and do not include books having several different ones. in such case the schedule might be headed by a miscellaneous group, having either the title "miscellaneous" or the title of the class, to receive associated characteristics not provided for by specific titles, immediately followed by subclasses for the particular associations found to be most numerous, as follows: books. miscellaneous. subject-matter and language. subject-matter and binding material. subject-matter. language. size. binding material. to illustrate further, selecting for the purpose a mass of objects presenting problems more nearly like those presented to the office in questions of patentability, let it be assumed that one is to classify the objects in a heap of metal scrap. on looking over the material of the heap it is noticed that there are a large number of metal balls; some have holes through them, some are hollow, some are smooth on the outside, and some are hollow, smooth, and perforated, but they are all nevertheless balls, and accordingly all balls can be separated out and placed in a heap by themselves. next, the presence of bars in the general mass is observed, some long, some short, some straight, some twisted, some of round stock, some of square stock, etc. these may be gathered together and placed in a separate pile at the left of the balls. it is further observed that there are many differently shaped annular bodies in the heap resembling generally the single links of a chain, some circular, some elliptical, some twisted, some made of round stock, some of square stock, etc. they are all nevertheless annular bodies; these may be placed in a separate pile at the left of the bars. now, in the remnant of the original heap, a sufficient number of similar single elements does not remain from which to make a smaller pile of elements. different combinations of links, balls, and bars are, however, observed in the remaining heap. some are combinations of links, some combinations of a ball and link, some of a bar and link, and some of a bar, link, and ball. these different combinations may be separated out in the order named and placed in separate piles. after all these things have been removed, there is left in the original heap a number of odds and ends or miscellaneous metal objects. these several groups may now be arranged in the inverse order in which (in the particular illustration adopted) they have been removed, thus: . miscellaneous (remnants of the original heap of scrap). . combined bar, link, and ball. . combined bar and link. . combined bar and ball. . combined link and ball. . chains. . links. . bars. . balls. knowing that objects of metal scrap not covered by the specific titles will be found in the miscellaneous group, and that the more complex specifically-named things are to be found first after the miscellaneous or at the left of the row of piles of materials thus separated and arranged, and the more simple things and parts farther to the right, the particular piles to resort to for the things wanted may be definitely determined. the same processes may be applied to each of the piles. thus, balls, in the above illustration, may be divided into-- balls-- . hollow perforated. . hollow grooved. . hollow. . perforated. . grooved. again, the same processes may be applied to a mass of more diversified junk, of which the metal scrap may form one pile, rags another, old bricks another, old timber another, and, still another, timber having metal-straps, bolts, nails, etc., connected with it. _superiority and inferiority._--in the arrangement of subclasses in a class, those groups that are related to each other as wholes and parts are arranged so that the wholes shall stand before the parts, and so that subclasses defined by effect or by special use shall stand before those defined by function or general use. for example, in the scrap illustration above, assuming the titles to be in a printed arrangement, "chains" precedes "links," which may be parts of chains, and if it had been desired to separate animal-drags, for instance, from the scrap, some animal-drags being particular adaptations of a bar, links, and ball, the group of animal-drags should precede "bar, link, and ball." the words "superior" and "inferior" have been used to indicate this relationship. a class or subclass defined to receive a certain combination is superior to one defined to receive an element or a combination that is a part of that certain combination. a class or subclass defined to receive means for making a particular product, as an electric lamp, is superior to a class or subclass designed to perform a general function, as pumping air from a container. and whenever a question of assignment of a patent or application that contains matters of two or more groups bearing that relation is raised, the "superior" group is selected to receive it. further, in those instances in which groups are formed on different bases or different characteristics, not comparable with each other, and a patent is presented having matter falling in each group, that group which is highest in position is preferred in those instances where separate provision for means having both characteristics has not been made. in cases of necessity, as where a combination is presented for which no class has been definitely provided, but classes exist into which the several parts would fall if separately claimed, the same practice that obtains in similar situations with respect to two or more _subclasses_ of a class may be followed with respect to two or more _classes_ and the patent placed in that class which, in accordance with above-stated principles, should be deemed the "superior." _definite positional relationship of subdivisions._--in the metal scrap example, above, division has been effected on the one basis of form or contour. if it had been desired to separate also on material, for example, if it were deemed important to locate all brass scrap, each of the groups based upon form could be divided into one of _brass_ and one _not brass_, or the entire heap could be divided into _brass_ and _not brass_, and under the heading "brass" could be indented the various articles made of brass, and under "not brass" the various articles not made of brass, and this would double the number of divisions. if also it were desired to separate the lead articles in the same manner the number of classes would be tripled. but, as in the book illustration, it may be impracticable thus to multiply subdivisions, and the basis "form" having been selected as of _first-rank_ importance, all divisions based upon form should be completed and kept together. then, "material," having been selected as of _second-rank_ importance, should be carried out with respect to all objects in which form is non-essential. if enough brass balls were found to render it advisable to make a subdivision of them, they should be assembled into a subclass indented under "balls" and not into a subclass indented under "brass." having selected one basis as _primary_, it should never subsequently be made _secondary_ or _vice versa_. some such restriction on modes of division appears salutary in a system of divisions designed to definitely limit search. the arrangement herein sought to be explained is susceptible of use to limit all searches for a single definitely stated invention to a subclass properly entitled to receive it or those indented under it, and to those subclasses above, which may include it as a part of an organization or specialized means. as between coordinate groups divided on the same basis, there is no question of superiority and inferiority. the terms "superior" and "inferior" are useful in questions of relationship between combinations and subcombinations or elements thereof, and between groups founded on effect or product and those founded on simple function. the mere difference in complexity of mutually exclusive coordinate groups involves no relationship of superiority or inferiority. a subclass to receive a screw-cutting lathe is superior to a subclass to receive a lathe-headstock, a locomotive class is superior to a class to receive steam-engines, for the reason that the lathe is a whole of which the headstock is a part, and the locomotive is an organization of which the engine is an element. but the headstock subclass is not superior necessarily to the tailstock subclass simply because the headstock is commonly more complex than the tailstock. yet arbitrary preference for classification in the headstock subclass may be established by position where an application or a patent contains claims for both. thus in a class that is founded on a well-chosen basis that brings together things bearing close resemblances to each other, all types that contain the elements essential to produce a complete practically operative means will be found in subclasses that have a position somewhere between the beginning and end of the list of subclasses of the class. those that add features of elaboration of the essential types and those that are highly specialized to some particular purpose within the definition of the class will stand above the essential type subclasses, while those subclasses for parts and details will stand below those for the essential types. _indented schedules._--in an indented schedule all subclasses in the first column reading from the left are species to the genus represented by the class title.[ ] all subclasses indented under another subclass are species to the genus represented by the subclass under which they are indented. if a title has no number, it represents merely a subject-matter to be divided, a genus,--having no representatives except in the species under it. if a subclass having a generic title has a number, it not only represents a subject-matter to be divided into species but also all other species not falling within the titles indented. although these relative positions might imply that only proximate species are indented one place, yet mechanical difficulties render it impracticable to so arrange that all species shall be indented under their proximate genera. indention properly carried out has a tendency to prevent in the process of logical division the logical fault of proceeding from a high or broad genus to a low or narrow species. this latter fault may inadvertently separate things that belong together. if, for example, it were desired to divide balls in the stated illustration according to material, an immediate division of balls into aluminum, zinc, glass, ivory, rubber, would be less useful than to divide into mineral materials and nonmineral materials as follows: balls-- mineral-- nonmetallic-- glass. metallic-- aluminum. zinc. nonmineral-- vegetable-- rubber. animal-- ivory. however, it is evident that indention carried to its full extant, useful as it is in keeping analogous things together, would make the printing of schedules complex and unwieldy. nevertheless, in the generalizing process necessary in logical division and arrangement, the divisions of species should always be _mentally indented_, as it were, under their _proximate_ genera. thus, under a genus unnamed may be arranged several species in juxtaposition, without actually printing the name of the genus, so that the schedule above may read: balls-- glass. aluminum zinc. rubber. ivory. in an arrangement printed in idea-order, though relegating the genera mineral, nonmetallic, metallic, nonmineral, vegetable, animal, to the mind unaided by printed words, the different species of the same genus may be kept together except that species for which no title has been provided must go back to the subclass under which the named species are indented. thus the arrangement above necessitates placing in subdivision "balls" all _copper_ balls, whereas indention under proximate genus "metal" would have brought all metal balls together. in a finely divided classification, printing of titles for all genera is not practicable; hence great care ought to be directed toward grouping species according to the principles of arrangement herein outlined, noting that whenever a change of basis is made, a new genus is implied, and that subclasses for all other species of the same genus under whatever name, must be brought into juxtaposition as if indented under the implied genus.[ ] _bifurcate division._--most discussions of classification make reference to the so-called bifurcate scheme of division as the only one by which exhaustive division can be surely achieved. this is commonly illustrated by the ancient tree of porphyry. by this method any subject it is desired to subdivide is first divided by writing the name of one selected species at one branch and writing at the other branch the name of the same species prefixed by "not." thus the agassiz classification of living beings divides them first into sensible and not sensible (plants). a botanical classification divides plants into flowering and not flowering. a zoological classification divides animals into vertebrate and not vertebrate. by continuing the process of division in the same manner, the division is obviously exhaustive of the subject, there being always a negative subdivision to receive any subsequently created or discovered species. although bifurcate division has been ridiculed by some, it is agreed by highest authority that it is the only plan of division by which one can be sure to have a consistent place for everything, or by which one can be certain that the divisions are mutually exclusive. it can be demonstrated that a classification schedule in which the relation of genera and species is shown by indentions, if correctly formed on the principles now sought to be applied in the revision of the patent office classification, is susceptible of conversion into a tree of porphyry, while unlike the latter it is compact and wieldy. _utility of arrangement according to resemblances._--the expedient of indicating kinds of relationship between several equally indented divisions by relative position has the following utility: ( ) a uniform rule is provided, applicable to all classes, for placing inventions that bear the relation of whole to part in subdivisions before those that bear the relation of a part to that whole, and those that are defined by a particular effect, product, material, or use before those that are defined by a function or an operation applicable generally to various effects, products, materials, or uses; whereby that portion of the schedule in which any invention belonging to any particular class should be found may be approached whether or not the investigator knows the name of the object sought for or the title of the appropriate subdivision. ( ) the substantial impossibility of dividing many branches of the useful arts exhaustively into a reasonable number of mutually exclusive or non-overlapping subclasses is compensated for; so that when the classifier or the searcher has an invention to place or to find including two or more different kinds of characteristics, for each of which a subdivision is provided, but no subdivision for the plural characteristics, it will be known that the invention should be in the subclass for that characteristic which stands before the subclass for the other characteristic. ( ) it compensates for omission of some generic titles that if written in the indented schedule would lengthen specific titles to a cumbersome extent. ( ) it provides a rule for cross-referencing where several inventions are claimed bearing to each other any of the relationships indicated above, cross-referencing being necessary in one direction only where the matter illustrated is coextensive with the matter claimed. ( ) it definitely limits the field of search for any _unitary invention_ in any class so arranged, as no patented invention having the limitations imposed by a unitary claim should be found in any subclass below the subclass properly defined to receive it or those indented under it. parts of such inventions may be found below or following this subclass in the same class if these parts are within the class definition, or elsewhere in the useful arts if not within that definition. the unitary invention may be found in the subclass limited to it and certain subclasses arranged _above_ or _before_ it adapted to receive organizations of which it may be a part. a complete system of arrangement should comprise ( ) a display of the entire field of the useful arts in a manner to show the relation of the larger as well as of the smaller groups,--carrying the appropriate relationship as far as possible from the highest genera to the lowest species, the arrangement being such as would bring materials most nearly alike into closest propinquity regardless of the names they may be called by. ( ) supplementary to this classification arrangement by ideas there should be an alphabetical index of subclass titles, appropriately cross indexed, and additional titles of various technical and trade names of things classified under subclass titles. definition. definition is indispensable in any classification and is very difficult. every class must be defined and all of the groups under it. after definitions have been made and printed, they are sometimes found inadequate and must be supplemented by the definitions of other classes. this is unavoidable while the complete material remains unexplored. definition in the strict logical sense is not to be expected, nor is it necessary. it is commonly sufficient if an explanation or comparison be made sufficient to direct the mind to the character of the contents of the group and indicate its limitations. hitherto four of the five predicables of ancient logic have been mentioned, to wit, genus, species, property, and accident. in connection with definition, the fifth predicable, difference, is useful. to define a class, it is sufficient, generally, for the purposes of office classification, to state a _peculiar property_ (not an accident) of the objects included in the class; and to define a species under the class it is sufficient to state the name of the class plus the difference--i. e., with the addition of the limitations that characterize the species.[ ] this procedure in definition is susceptible of application from the highest genus to the lowest species. it is advisable to define the means included within a title without any introductory words, such as "this subclass includes inventions relating to," etc., treating the subclass for definition purposes as if it were a collection of concrete things, in the same manner as in a dictionary definition. cross-references and search-notes.[ ] if patents were in all respects like material objects, cross-references and search-notes would not be necessary. nails, screws, locks, hinges, and boxes are distinct things susceptible of definite separation and classification. even though nails, screws, locks, and hinges form part of the box, the box is still a box, not a nail, screw, hinge, or lock. for the needs of the patent office classification, however, although a patent for a box must be classified with boxes, yet if a peculiar nail, screw, lock, or hinge is claimed in the same patent with the box, or even if any one of these customary accessories of boxes is illustrated, it may be necessary to provide copies of the patent for the box in each of the several classes provided for nails, screws, locks, or hinges. inasmuch as every relatively complex thing is made up of relatively simple things, it is obvious that all disclosures can not be cross-referenced. any attempt to calculate the number of cross-references to be supplied if all disclosures of the subjects of invention were to be cross-referenced would show the number to be incalculable. it is necessary, therefore, to leave to the judgment of the classifier the propriety of cross-referencing unclaimed disclosures. should a patent contain a number of claims defining a number of differently classifiable inventions, complete cross-referencing from the class in which the classification is made original into the other appropriate classes or subclasses should be effected, _unless_ cross-search notes or arrangement of subclasses with appropriate titles may be substituted to advantage. cross-referencing or cross-search notes are made, as a rule, from combination class to element class, but never or very rarely from the element class to the combination class in which it may be used. thus cross-referencing should normally be downward in a schedule of subclasses. search notes indicate parallel or otherwise related classes and subclasses, and those classes and subclasses in which analogous structures having different purposes but adapted to answer broad claims may be found. by arbitrary rules of arrangement such as have been referred to in the section dealing with division and arrangement, a search may ordinarily be definitely limited to a certain number of subclasses, even where cross-references are not made. in such arrangement any given patent, _if it be directed to one invention_, may be searched in the subclass within which the definition places it or subclasses indented under it, and in certain subclasses above, whose titles will indicate that the invention might be included as a part of the matter defined to belong therein, but it would never have to be searched in any subclass following and not indented thereunder. diagnosis to determine classification. each patent and each application discloses one or more means of the useful arts (using the term "means" to cover both processes and instruments in the sense in which it is used by prof. robinson), almost always more than one, since most new means are combinations of mechanical elements or acts. in some patents and applications the disclosure is coextensive with that which is claimed; in others there is matter disclosed but not claimed. the unclaimed disclosure may be as valuable as the claimed disclosure for purposes of anticipation, and the classification must provide for both. if the claimed disclosure belongs in one class and the unclaimed in others, the classifier must choose between two or more classes that one in which the patent or application shall be classified and those into which it shall be cross-referenced. _claimed or unclaimed disclosure._--the claims of a patent are the statutory indices of that which the applicant believes to be new, they define an invention that has been searched by the patent office and no anticipation discovered for it. future action must be based on inductions from past experience; none knows what the future lines of search will be; the only guides for future searches are the searches of the past; the evidence of past searches is the claims of patents; they trace the course of invention. furthermore, a presumption of novelty attaches to the claimed matter; no such presumption attaches to the unclaimed. the law requires every patent for improvement to show so much of the old as is necessary to explain the uses of the improvement. in practice much more than that is disclosed. questions as to the proper placing of patents and cross-references would be diminished by the strict enforcement of rule of the rules of practice requiring that the description and the drawings, as well as the claims, be confined to the specific improvement and such parts as necessarily coöperate with it. in any event both the claimed disclosure and that which is unclaimed must be taken care of, one by cross-reference, and the disclosure selected for cross-reference is that to which no presumption of novelty attaches. this practice of placing patents by the claimed disclosure is sometimes misunderstood. its chief application is in determining classification in case of disclosures involving a plurality of main classes. furthermore, the mere letter of the rule is not to be applied in preference to its spirit. subcombinations claimed may be placed with the combinations, and in subordinate type subclasses patents must be placed sometimes by claimed and sometimes by not-claimed disclosures. _diagnosis of pending applications._--what has been said relates to patents. the bearing of the practice of adopting the claimed disclosure as the basis of assignment of applications for examination has also to be considered. two pending applications claiming the same means very commonly differ in the kind and extent of disclosure. one application may disclose several inventions. which of the several disclosures shall be selected as the mark by which to place the application? for instance, the typical wire-nail machine has a wire-feeding mechanism, a shearing mechanism, an upsetting (forging) mechanism, side-serrating mechanism, and pointing mechanism; it may also have a counting mechanism, a packaging mechanism, an electric motor on its frame for furnishing power; and, in addition, numerous power-transmitting and other machine parts, such as bearings, oil-cups, safety appliances, etc. the applicant may have made a complete new organization of nail-machine and may seek a patent for the total combination. he may have invented a new shearing mechanism and have chosen to show it thus elaborately in the place of use he had in mind, or he may have designed a new counter or a new oil-cup or a new power transmission, or even a new motor, and have given his invention this elaborate setting. the shears, the counter, the oil-cup, the power transmission, and the motor are separately classifiable in widely separated classes. how shall the application be diagnosed for determining its place in the office classification? when the specification and drawing disclose (as most of them do) several subjects matter of invention, though claiming only one, which of those several subjects matter shall control the classification? the most natural procedure, at first thought, would be to classify on the totality of the showing, in which case the application for the nail-machine, supposed above, would be assigned to nail-making. but imagine the invention claimed by an applicant to be the counter. then the examiner in charge of nail-making would have to search the class of registers with which he is not familiar. suppose applicant no. files an application for the same counter which he illustrates and describes in connection with a bottle-filling machine, and that, classifying on the totality of the showing, this goes to the division that has the class of packaging liquids. now both the examiners in charge of bottle-filling and nail-making, knowing that counters are classified in registers, search the class of registers and also the pending applications in registers. after these examiners have made their searches, suppose applicant no. files an application for the same counter, which he says may be used for counting small articles produced by automatic machines. perhaps he shows the counter attached to a piece of conventional mechanism representing any manufacturing machine, mentioning, say, a cigarette or pill or cartridge-making machine. it has not occurred to either the the examiner of nail-making or the examiner of bottle-filling that the other might have any such application; nor does it occur to the examiner in charge of registers to search nail-making or bottle-filling. as the specification of the counter application mentions cigarette, pill, and cartridge-making machines to which the counter may be attached, the examiner in charge of registers may search those classes. suppose that the counter proves to be new, and each of the three examiners allows a patent. here now are three patents for the same thing. of course, after allowance, the counter and all other disclosed inventions that give any suggestion of novelty are cross-referenced; but the primary purpose of a patent office classification (to aid in determining patentability) has failed in this instance. in the imagined situation respecting pending applications, without doubt diagnosis and classification upon the invention claimed is necessary to effect the purpose of the office classification. cross-referencing after issue can not undo that which has been done. if no application save that of the nail-machine be pending, no duplication of patents occurs, but the labor of search is increased by reason of the unfamiliarity of the examiner with the inventions he has to search. after the patent is allowed he may find the entire combination of the nail-machine without the counter disclosed in a patent for a nail-making machine, so that as a nail-making machine this new patent is of no value as a reference. very probably all of the other inventions illustrated (except the counter) are also old in their respective classes; but the examiner of nail-making can not tell this without extensive searches in those classes, so he notes cross-references for them all. _difficulties due to varying ideas of claims._--very troublesome questions are constantly arising as to whether an invention should be classified in a combination class or an element class. the point will be illustrated by example: a describes and illustrates an automobile having an internal-combustion motor and a friction-clutch in the motor transmission-gear. he states that the clutch is in the usual relationship to the motor and gearing, but claims a new clutch for whatever it may be adapted. b discloses an internal-combustion motor said to be for automobiles with transmission-gearing and a friction-clutch and claims "in an internal-combustion motor a friction-clutch," etc., specifying the form of the clutch. c makes the same disclosure, but claims "an internal-combustion motor having a specified clutch," while d, with the same disclosure, claims "the combination with the internal-combustion engine of an automobile" of a specified friction-clutch. e claims and illustrates only the friction-clutch. should these be classified together? if so, in what class? should a bearing composed of a specified alloy of copper, tin, and antimony, be classed as a bearing or as an alloy? should a house painted with a mixture of linseed oil, lead oxid, and barium sulphate go to buildings or coating compositions? a lamp-filament of titanium and zirconium with electric lamps or with alloys? a building-block of cement, lime, sand, and carborundum, with building-blocks or plastic compositions? whether these be diagnosed as combinations or as elements and compositions respectively, and classified accordingly, criticism will be aroused. the point in view is that although principles of patentability must be considered in a classification designed as an instrument to aid in determining patentability, convenience and accuracy of search and avoidance of voluminous cross-referencing may necessitate some arbitrary rule of classification to meet various and changing theories applied to the drafting and allowance of claims. from the foregoing it will be evident that classification involves orderly logical processes of induction (supplemented by hypothesis), of definition and of deduction. after gathering a large number of facts generalizations are made from them and a hypothesis is found to be confirmed or modified by more extended research; the divisions are then defined; by correct diagnosis of other instances (as other patents) deductions may be drawn respecting the appropriate place for them in the classification. [ ] an "art," in the sense of a single unitary invention, is a synonym of process, method, and operation. the term "art" is ambiguous in popular usage. in the phrase "useful arts" in the constitution, it denotes the area of endeavor to which the patent laws apply. when the word "art" is used to specify some fragment of the useful arts, it commonly raises different notions in different minds. it may be correctly used to designate _any_ division of the useful arts. it is as proper to speak of the art of grinding or the art of molding as of the art of metal-working or the art of brickmaking. [ ] a "use" is an application of a means to substance to produce an effect which may or may not be the necessary effect of the means in its normal operation. a catalytic may be used to ignite gas or to convert oleins into stearines. an ice pick may be used to hold a chalk line or prick holes in leather, etc. [ ] by "natural law" in the useful arts is meant that uniformity of action which is manifested whenever any particular substance in any particular condition is brought into such relation with any particular manifestation of energy that the force exerted modifies or prevents modification of the form, nature, condition, or locus of the substance or modifies the manifestation of energy or both. [ ] a "property" may be described as any quality common and essential to the whole of a class but not necessary to mark out that class from other classes. thus, all wheel tires may be said to possess annularity; but washers and finger rings are also annular. a "peculiar property" is one that not only always belongs to a class of objects but belongs to that class alone; thus a circle has the peculiar property of containing the greatest space within a line of given length, and catalytic substances have the power of setting up chemical reaction without themselves being changed. [ ] an "accident" is any quality that may indifferently belong or not belong to a class without affecting the other qualities of the class. that a man's name is james is an accident telling nothing of the man's physique or character. [ ] "effect" or "result" is the consequence of a process of the useful arts practiced with or without instruments. the effect of an instrument is the effect of its operation. effects may be direct or indirect, proximate or remote, necessary or accidental. "product" is an effect consequent upon a process that changes the form, state, or ingredients of matter perceptibly and permanently, as distinguished from effects that are fleeting or involve no change in perceptible form, state, or ingredients of matter. "function" is the "action of means upon an object while producing the effect." (robinson.) functions may be direct or indirect, proximate or remote, necessary or accidental. the direct, proximate, or necessary function of the hammer in normal operation is impacting. indirect, remote, or accidental functions of a hammer may be comminuting, forging, driving, etc. [ ] classification of the sciences. [ ] logical division is the process by which the species of which a genus is composed are distinguished and set apart. physical division or partition is the process by which the parts of any object are distinguished and set apart. metaphysical division is the process by which the qualities of a thing are segregated and set apart in thought. [ ] any class of objects may be called a "genus" if it be regarded as made up of two or more different kinds of objects or of two or more species. "motors" is a genus when the class "motors" is considered as divided into electric motors and nonelectric motors, or electric motors, spring motors, weight motors, current motors fluid pressure motors, etc. a genus is more extensive than any of its species but less intensive. a "species" is any class that is regarded as forming a part of the next larger class, "electric motors" being a species of "motors" and "motors" being a species of "energy transformers." a species is more intensive than the genus to which it belongs but less extensive. every species may be a genus to another species until no further subdivisions can be made. this last indivisible species is termed the _infima species_. every genus may be a species to another genus until a point is reached where no further generalization may be made or the _summum genus_ is attained. in the patent office classification of the useful arts, the _summum genus_ is useful arts. the _summum genus_ of the plastic arts would be plastics. the _infima species_ in the useful arts evidently never can be attained. "proximate species" and "proximate genus" indicate, respectively, those species that are divided from a genus without intermediate genera, and those genera from which the species are directly divided. motors, and not energy transformers, is the proximate genus to the species, fluid motors, electric motors, etc., while fluid motors, electric motors, etc., and not steam engines, alternating current motors, etc., are proximate species to motors. [ ] in the manual of classification of the u. s. patent office the arrangement of subclasses has always been alphabetical, although in the supplement containing definitions of revised classes the arrangement is numerical. if the latter schedule of "balls" in the text had been printed in alphabetical order, it is apparent that the species "aluminum" and "zinc" of the genus metal would be as widely separated as possible. in the former schedule of "balls," in which the genus metal is printed, "aluminum" and "zinc" come together. it is apparent that in an alphabetical arrangement allied species can not be kept together without printing every proximate genus. this fact, among others, indicates the advisability of abandoning the alphabetical arrangement in the classification manual and adopting the idea arrangement in the schedules of revised classes, supplemented by a consolidated alphabetical index of all subclasses. [ ] a species contains all the qualities of the genus and more. these additional qualities form the "difference." the electric motor has the qualities that are common to motors and is differentiated by reason of the fact that electric energy is thereby converted to mechanical motion. [ ] classification of a patent is said to be "original" in the class and subclass which receives the most intensive claimed disclosure, and in which the patent is indexed in the official classification indexes. "original classification" is referred to as opposed to "classification by cross-reference." a "cross-reference" is a copy of a patent placed in a subclass other than that in which the classification is made original, in order to make available for search inventions disclosed therein and additional to that by which the patent has been diagnosed and classified. a "digest cross-reference" is a cross-reference formed from abstracts or extracts from a patent consisting of illustration and text cut from a photolithograph of a patent and mounted. a "search-card" is a sheet of the size of a photolithograph of a patent placed with the photolithographs of patents forming a subclass in the examining division and public search room, and containing suggestions for further search, and on the copy for the search room, a definition of the subclass. "search notes" are addenda to class and subclass definitions comparing other classes and subclasses with the one defined and giving directions for search when necessary to prosecute search beyond the defined class or subclass. (c) rules of classification. basis of classification. ( ) the basis of subdivision and assemblage of the means of the "useful arts" in the patent office classification is "art" within the meaning of "art" in section , revised statutes. the direct, proximate or necessary art, operation or effect, rather than some accidental and remote use or application, should be selected. in all cases qualities or characteristics that persist through all accidental uses and that can be identified as permanent are to be preferred. ( ) the operative, instrumental, or manipulative arts, including machines, tools, and manufacturing processes, should be classified according to whether a single operation of one kind applicable to various materials to be used for various purposes is carried out by the claimed means, or whether plural operations are performed, which, combined, produce a special effect or special product. example: an instrument performing a plurality of operations peculiar to shoe-manufacture would be classified on the basis of shoemaking, because that instrument would be incapable of other use, while an instrument peculiarly adapted to drive nails would be classified on the basis of nailing, whether for nailing shoe-heels or other objects, and a hammer would be classified on the basis of its function as an impact tool even though described as for driving nails, and even into shoe-heels. ( ) structures (passive instruments) will, in general, be classified on the basis of structure, either of special or general application, the essential functions and effects of static structures being resistive or the maintaining of forces in equilibrium. example: a structure recognized as peculiar to barriers of the kind known as fences would be classified in the special class of fences, but posts, joints, beams, etc., recognized as having use in general building, even though described as used in fences, would be classified in a more general building class, such as wooden buildings or metallic building structures. ( ) compositions of matter and manufactured or formed stock or materials will be classified in accordance with the inherent character of the substance or material where possible, otherwise according to special use. example: a pure chemical is expected to be classified on the basis of its chemical structure and constituents, even though useful as a food, medicine, dyestuff, explosive, etc., and alloys on the basis of metallic composition, even though used for bearings, coins, tools, etc.; whereas a physical composition having no reason for existence except to function as a cleansing composition or a paint might have to be classified on the basis of its function as a detergent or a coating composition, respectively. also a bimetallic layered foil, plate, or wire would be expected to be classified as metal stock even though designed for use for dental filler, plowshare, or electric conductor, and a woven textile fabric as a fabric even though described as used for a filter or apron for a paper-making machine. division and arrangement. ( ) the divisions or subclasses of a class should be made exhaustive, i. e., they should be susceptible of receiving any future invention that may fall within the scope of the class. the rule as usually phrased is: "the constituent species must be equal, when added together, to the genus." exhaustive division may be secured by maintaining always a residual or miscellaneous subclass. the miscellaneous subclass represents the remainder of the original undivided material undefined except as the class is defined and may be accurately treated as if it had the class title. ( ) a second rule respecting the subdivision of a class is: "the constituent species must exclude each other." that is, the divisions or subclasses must not overlap. (see exception in rule .) example: if a number of balls of several different materials, several different conformations, or constructions, several different colors, were to be divided into glass balls, hollow balls, and red balls, this rule would be violated, because some balls would be glass, hollow, and red. ( ) a third rule respecting subdivision is: "the divisions must be founded on one principle or basis." the application of this rule will generally form divisions that do not overlap. (see exception in rule .) example: if a number of balls of several different constructions, several different materials, and several different colors were to be classified so as to provide a place for each kind of characteristic, they should be divided first, for example, according to construction into hollow balls and solid balls, each of these according to materials into glass balls, rubber balls, metal balls, wooden balls, etc., and each of the latter into red balls, blue balls, green balls, etc. ( ) when it is found that division into overlapping subclasses and on different characteristics is a lesser evil than an unwieldy number of subclasses that would otherwise result, then those subclasses based on characteristics deemed more important for purposes of search should precede in the list of subclasses those based upon characteristics deemed less important. (see rule .) ( ) in arrangement of subclasses or subdivisions the miscellaneous groups containing material not falling within any of the specifically entitled subclasses, should stand first; those subclasses defined by effect or special use should precede those defined by function or general use; those containing matter that is related to the matter of other subclasses as whole to part should precede those subclasses that contain the part; and those defined by a characteristic deemed more important or significant for search purposes should precede those defined by characteristics deemed less important. _whenever superior rank has been assigned to any selected characteristic_ by placing divisions based upon it in advance of divisions based upon other characteristics, _this superiority should be maintained throughout_. example: a partial schedule of class follows to illustrate the arrangement of subclasses: class .--metal rolling. . miscellaneous. | . die rolling-- . heating and rolling. | . oscillating rolls. . cutting and rolling. | .. ... . drawing and rolling. | mills-- . annular bodies. | . coiling. . screw threads-- | . work reversing. . concave and roll. | . three or more coacting rolls. . platen rolling-- | . continuous-- . dies. | . inclined trains. . rods and wires. | .. ... . tubes-- | . roll cooling and heating. . idle rolls. | . cooling beds. . axial rolling. | . feeding-- . segmental rolls. | . tables. . skelping. | .. ... . wheels and disks. | . housings. . reworking. | . roll adjustments-- . concave and roll. | . relief devices. . platen and roll. | . rolls-- . platen rolling-- | .. ... . disk platens. | . processes-- . axial rolling-- | .. ... . pattern rolls. | . flanged bars. in this schedule the miscellaneous subclass is numbered , then follow three subclasses ( - ) of rolling plus another function, then four major subclasses ( - ) of rolling, merely, but applied to blanks of special form producing special products, then one special subclass ( ) based upon a special class of material treated, then five subclasses ( - ) specialized in type and mode of operation, then general types of rolling mills ( - ), then various parts and accessories ( - ), then processes ( - ). this is the usual arrangement and is an exhaustive division for the art of metal rolling. had there been miscellaneous subclasses for all combined operations of rolling plus some other function, a miscellaneous subclass for all mere rolling machines, either special or general, and a miscellaneous subclass for all parts and accessories, the requirements of exhaustive division would have been also satisfied. in the illustrative schedule, there being no miscellaneous subclass for means having combined functions of rolling and another, any patent having claims for the combination of a means for rolling and a means for cooling would fall in subclass , miscellaneous. in that subclass would also fall all "mills," such as for rolling spiral conveyer-flights, the same not falling under any of the subclasses - , no miscellaneous subclass of "mills" and no special article-rolling subclass having been provided; also all parts or accessories, such as a water-cooled screen, peculiarly adapted to rolling-mills, there being no existing subclass of screens therein and no miscellaneous subclass of parts. the arrangement of subclasses in class requires that the combination of a furnace and a rolling-mill shall be placed in subclass , even if the combination be designed and adapted for rolling annular bodies (subclass ) or tubes (subclass ). means special to rolling a tube between a concave and roll must be placed in subclass rather than in subclass . a work-reversing mill must be placed in subclass rather than in subclass even though it have three or more coacting rolls. the rolling of "screw-threads" having been given higher rank than a "concave and roll" mechanism, any concave and roll mechanism limited for use in rolling screw-threads should be formed into a subclass indented under "screw-threads" and not into a subclass "screw-threads" indented under "concave and roll." ( ) class schedules are arranged with certain subclasses appropriately indented according to a commonly understood expedient. in a properly indented schedule subclasses in column at the extreme left are the main species (the proximate species) of the class. the titles and definitions of all subclasses proximate to the class (at extreme left) must be read with the title and definition of the class, as if indented under the class title one space to the right; so also with the titles and definitions of subclasses indented under other subclasses. if a title has no number (as in class , "mills"), it represents merely a subject-matter to be divided, assumed to have no representatives other than those in the species indented under it. if a title having indented species under it has a number, it not only represents a subject to be divided but also a subclass including all other species not falling within the indented titles. indention does not indicate superiority or inferiority, but merely that the title and the definition of the indented subclass must be read with the title and definition of the subclass under which it is indented. a title selected in a scheme of subdivision to be of first importance and placed, therefore, in advance, should not thereafter be indented under a title selected to be of secondary importance and, therefore, having a lower position. (see rule .) ( ) a group of material may be divided on several different bases. "use" or "purpose" or "object treated" may be adopted only when the "use" or "purpose" or "object treated" stamps upon the invention such peculiarities of operation or construction as to limit the applicability of the invention to the use or purpose named. (see basis of classification, rule .) a group based upon mode of operation also may be divided into subclasses ( ) with a "functional" title, usually participial in form, and adapted therefore to receive machines, processes, and tools; ( ) with special use, purpose, or object-treated title containing the name of the use, purpose, or object; ( ) with "type" title, usually a name or a name with a qualifying adjective; ( ) with a title of a part or subcombination, also a name. example: in class , gear-cutting, milling, and planing, are to be found subclasses entitled "gear-cutting," certain machines being peculiar to that use; also other subclasses with the general functional title "planing," subordinate to which are the special use subclass "planing, soft metal," and the type subclass "planers" divided into two coordinate subclasses, "reciprocating bed" and "reciprocating cutter," and several subordinate "part" subclasses, including "tool-feeds" and "tool-heads." the adjective form of the title "planers, reciprocating bed," indicates a type subclass. if the title had been planers, reciprocating beds, the indication would be that the subclass was a part subclass to receive planer beds only. in the class referred to for illustration, "tool-feeds" and "tool-heads" indicate subclasses for parts and not for types of planers having tool feeds. ( ) in arranging the divisions of a class, such arrangement should be sought as will minimize the need of cross-references. search for any particular matter can not always be limited to one group without such extensive cross-referencing as would in some cases defeat the purpose of classification. forming the subdivisions of a class according to the total similarities of the inventions, rather than according to some selected more or less important characteristic, and arranging them in the correct order of superiority and inferiority, with care to maintain throughout the schedule the relative positional values of the several selected bases of division, will ordinarily in a closely bonded class limit the search for any single invention to the subclass particularly suited to receive it and some subclasses preceding that one, excluding from the necessity of search the subclasses succeeding. example: in class , metal-rolling, it would not be expected to find any tube-rolling mill lower in the schedule than the tube-rolling subclasses, but a tube-mill might be found higher up in "heating and rolling," "drawing and rolling," etc. no concave and roll combination should be found succeeding the subclass of "concave and roll," but it may be found under subclasses above, such as "tubes, screw-threads," etc. no rolls should be found lower than the subclass of "rolls," but they may be found in many subclasses above. definition. ( ) having some knowledge of the nature of the materials about to be classified, a tentative definition of a class to be formed may be framed, which may be either written down or merely carried in mind, to serve as a tentative guide. this tentative definition must be considered as subject to change to any extent by the fuller knowledge obtained by careful consideration of the material. after a full knowledge of the materials to be classified has been acquired, it will be necessary to frame a careful definition of the class, and also of each subclass whose title does not unequivocally indicate what is contained in it. ( ) a definition of any class should state the "qualities and circumstances possessed by all the objects that are intended to be included in the class and not possessed completely by any other objects." a proper definition should not ordinarily contain the name of the thing defined. "definitions in a circle" are, of course, worthless. a definition should be exactly equivalent to the species defined and should not be expressed in obscure or ambiguous language, but should employ terms already defined or perfectly understood. it should not be in negative form where it can be affirmative. if the class of objects has a peculiar property, the naming of that may serve as a definition. if no peculiar property can be detected, the definition should name more than one quality or property. several different classes may have one or more properties alike, but as the number is increased the likelihood of there being others having the same properties is decreased. the briefest possible statement of such properties or qualities as are possessed by all the objects of a class and not completely possessed by any other objects, which will suffice to distinguish the class from other classes and determine its position in the general classification, will be most satisfactory. to define any species, the genus having been defined, the genus should be named and the difference added. of course, no generic definition should contain any limitation not characteristic of every species of the defined genus. in seeking qualities by which to describe a genus or species, no accident should be selected. example: suppose there be marked out and defined as a genus all means whereby one form of energy is transformed into another form of energy and no more, and the genus be named energy-transformers. we may then name, as species, energy-transformers that are motors and energy-transformers that are not motors. motors may be defined by merely naming the genus energy-transformers, and stating the difference, to wit, continuously transforming energy into cyclical mechanical motion. then the definition will be: energy-transformers that are adapted to continuously transform energy into cyclical mechanical motion. the non-motor division will retain the genus definition. it would not be illuminating for a searcher having little familiarity with the textile arts to look under the title "carding" and find that carding is defined as a means for carding fiber. even though the first steam-engine invented had been used to run a gristmill, the accident of its use as a part of a gristmill would hardly warrant the definition of a steam-engine as a means to grind corn. nor would a hammer be properly defined as an instrument to drive nails or to crack nuts or to forge horseshoes, even though a patent should not mention any use other than one of these and should lay heavy emphasis on the special value of the hammer as a nut cracker, nail driver, etc. ( ) in those cases where the title is so obvious that definition is superfluous, explanatory notes may be substituted and will usually be found helpful. cross-references and search-notes. ( ) inasmuch as nearly every patent discloses unclaimed matter that is classifiable separately from the claimed matter, it is clearly impossible to cross-reference every disclosure of every means in every patent. many things must be taken as conventional, obvious, or well known, and the good judgment of the classifier is bound to be exercised in cross-referencing matter disclosed but not claimed to be the invention of the patentee. ( ) a mere part or element should rarely be cross-referenced from an element class to a superior combination class. an element forming part of a combination in a superior class should, if claimed, be cross-referenced to the element class and also if not claimed if it seems to be not merely a conventional form, and patents having claims for more than one differently classifiable invention should always be cross-referenced unless such an arrangement of subclasses with search-notes is substituted as will guide the searcher to all places where the material may be found. claimed matter additional to that which controls the classification, if belonging in the same class, should be cross-referenced into a _succeeding_ subclass. cross-references of unclaimed disclosure may be in either direction. ( ) to supplement or take the place of cross-referencing, more or less elaborate search-notes are needed, giving directions and suggestions for further search, setting out the relationship between classes and subclasses, and drawing distinctions by example. search-notes should indicate other classes or subclasses in which the subject-matter of the group to which the search-notes are appended is likely to form a part of a more intensive combination, also analogous matter that might serve as a reference for a broad claim. they need not, in general, indicate where parts or elements of the subject-matter which are common also to other classes can be found, because the index of classes contains the necessary information. for example, it is not necessary in every machine-class to indicate by search-notes where machine-elements and static parts may be found, nor in a class of wooden boxes to point out where the nails, screws, hinges, or locks that may form a part of the box are classified. diagnosis to determine classification. ( ) inasmuch as nearly every patent contains disclosure that is claimed and also disclosure that is not claimed, it has been deemed advisable to establish the general rule that where the claimed and unclaimed disclosures are classified in different classes or subclasses the invention both disclosed and claimed shall determine the placing of a patent (or a pending application) rather than any selected invention that may be disclosed but not claimed. "not claimed" covers means that may form an element only of a claim as well as means not referred to in any claim. (see exceptions in rules to inclusive.) example: a patent discloses and claims a dash-pot but illustrates it in such relation to a metal-planing machine as to utilize it for checking the movement of the bed at one end of its path, or in connection with an electric generator to aid in effecting the brush adjustment; the patent should be classified in the subclass of dash-pots. if the classifier finds the disclosed organization of dash-pots and planer or dash-pot and generator more than a conventional illustration of an obvious use, he should note a cross-reference to planers or electricity, generation. a patent discloses an internal-combustion engine associated with a specific form of carbureter; the claims relate to the engine parts only; the class of internal-combustion engines should receive the patent, and a cross-reference should be placed in carbureters. a patent discloses and specifically claims the combination of a rail-joint comprising abutting rails, fishplates, and specific bolts; the patent goes to an appropriate class of rail-joints, and if the bolt is more than a mere obvious conventional bolt, a cross-reference should be noted for the appropriate subclass of bolts. ( ) the totality of the claimed invention should be selected when possible to determine the appropriate class in which to place a patent. the entire expression of the invention will usually be set forth in the most relatively intensive claim.[ ] in a properly drawn patent there is at least one claim that will serve as a mark to indicate the classification of that patent. ( ) where a patent discloses but does not claim a combination of proper scope to be classified in a combination subclass and claims merely a detail classified in a subclass lower in the schedule, both in the same class, if the subclasses are so related that the combination always involves the detail so that a search for the detail must necessarily be made in the combination subclass, the patent may be placed in the combination subclass. this avoids the need of a cross reference into the combination subclass, and a lack of a copy in the detail subclass is immaterial, as it is seen in the completion of the search through the combination subclass. (see rule .) example: a patent for a saw-making machine discloses dressing, jointing, and gaging mechanisms; it claims dressing and jointing only. there is a subclass for dressing, jointing, and gaging, and a subclass for dressing and jointing. in this case the patent may be placed in the first-mentioned subclass, as that must be searched always when the second-mentioned one is searched, cross referencing in this situation being of little value. ( ) where a subclass with a generic title has indented thereunder a species type-subclass bearing the title of the generic subclass qualified by a difference, any patent which claims an invention falling within the genus subclass and discloses the qualification of the species type-subclass should be classified in the latter whether or not the entire disclosure is claimed. (see rule .) example: class .--metal working. machine chucks and tool sockets-- cam closing-- . scroll-- . bevel pinion or ring. if a patent claimed only the scroll of a scroll-chuck, but disclosed it in connection with a bevel pinion and ring, it should be classified in subclass , bevel pinion and ring, and not in subclass , scroll, although if there were no disclosure of the bevel pinion and ring it would go in subclass . any search for scrolls must be prosecuted through all subclasses that include "scroll" in the title. ( ) where, as in the case of patents that show and claim a combination that as matter of common knowledge is not new except in one of its elements, to classify a patent strictly in accordance with rule would result in placing the patent where it would serve no useful purpose as a reference and having to cross-reference it to a class where it would serve a useful purpose, it is best to classify the patent in the class to which the element would take it. (see rule .) example: a patent claiming a wheeled vehicle, broadly, in combination with an internal-combustion engine comprising a cylinder, a crank-case, a piston and suitably-connected crank, a valve opening into the crank-case, and a valve in the piston opening into the cylinder, may be advantageously classified as an internal-combustion engine notwithstanding the alleged invention is for a motor vehicle. ( ) in order to meet the situation respecting the classification of those patents that indiscriminately claim an article of manufacture defined only by the material of which it is made and those patents that claim those materials, leaving to the specification information regarding the designed uses, patents for articles defined only by their ingredients specifically set forth may be placed in the composition of matter or material class. (see rule .) example: a patent having a claim for a cutter made of an alloy of iron, tungsten, and manganese would be classified with alloys; a patent claiming a box made of paper composed of two layers united by a solution of asphaltum should go to the class of laminated fabric and analogous manufactures, rather than to paper boxes; and a patent for a house having its exterior coated with equal quantities by volume of carbonate of lead and oxid of barium suspended in a vehicle of linseed-oil would be classified as a paint rather than as a house. ( ) an alleged process of utilizing a specifically-defined composition or material which consists in merely applying it to the use it was designed for may be classified as a composition or material rather than as a process. (see rule .) example: a process of painting the bottom of a marine vessel which consists in applying thereto a composition consisting of sulphate of copper, powdered metallic zinc, chlorid of antimony, and hyposulphite of soda, in a vehicle of linseed oil, would be more usefully classified as an antifouling paint than as a ship, as the invention would hardly be distinguishable from a paint claimed as such and described for use on submarine surfaces. ( ) an alleged process consisting merely in the use of a particularly-defined machine or similar instrument operating according to its law of action will ordinarily be classified in the class or subclass where the machine belongs. but if in addition to defining the operation of a particular machine the claim also specifies acts not performed by the machine, the classification should be in the class or subclass in which the process belongs. (see rule .) example: thus a claim for a method of rolling an iron plate which consists in passing an iron blank between a pair of rolls arranged horizontally in juxtaposition one above the other and geared together so as to rotate in opposite directions, and causing an idle roll supported in bearings on the roll-housings to bear against the central portion of the surface of one of the first pair of rolls on the upper side thereof, should be classified as a rolling-mill, while if to that claim were added the steps of doubling the sheet after one passage between the rolls, again passing between the rolls, again doubling, and then passing the now four-ply pack between the rolls sidewise or turned per cent to the direction in which it had previously been fed, the classification should be with processes of sheet-metal manufacture. ( ) in the absence of settled rules defining permissible joinder of inventions, there may be in one patent claims for one or more or all of the classes of invention named in the statute, to wit, machine, art, manufacture, and composition of matter. there may also be claims to several more or less related inventions in the same statutory class of invention but each belonging to a different industrial art. ( ) where different main classes are involved, the patent will be classified by the most intensive invention, without regard to the statutory class to which it belongs. ( ) where different subclasses of the same class are involved, the patent will be classified in that one of the several subclasses defined to receive the several inventions which stands highest in the schedule of subclasses. ( ) where a patent contains claims for all or a plurality less than all of the statutory classes, the general rule of preference or superiority of the several classes of subclasses is that represented by the following order, to wit: ( ) machine (or other operative instrument); ( ) art; ( ) manufacture; ( ) composition of matter. this order is, in a general way, the order of intensiveness of the several kinds of invention. (see rules - .) example: an automatic screw-machine, peculiarly adapted to carry out a process of making a novel form of machine-screw out of a new iron alloy, and having a claim to the machine, to the process, to the screw, and to the alloy, would be assigned to metal-working, combined machines, and, if all claims were allowed, cross-referenced to bolt and rivet-making processes, to bolts, and to alloys. if the claim to any one or two of the subjects were eliminated, the order of preference or superiority and the order of cross-referencing would remain the same. ( ) patents containing a plurality of claims for several different statutory kinds of invention that are classifiable in different main classes, and wherein the rule of relative intensiveness varies from the order machine, art, manufacture, and composition of matter, may be diagnosed and classified as directed in the following paragraphs ( to ). ( ) where a patent contains claims for a process and for an apparatus susceptible of use as an instrument in carrying out the process, but not peculiar to that use, or for an apparatus adapted to carry out but one step or only a part of the process, the process claim, being in this instance the more intensive, would control the classification. (see rule .) example: in a patent containing a claim for a process of roasting ore and then collecting the fumes, and another claim for a roasting furnace that is a mere material-heating furnace, the process claim would control; whereas, if one claim were for a method of roasting ores consisting of stirring the ore, applying heat to the same, and collecting the solids from the fumes, and the other claim, were for a heating furnace having a stirrer and a fume arrester, the apparatus claim would control. and if a patent contained claims for a process of roasting ores, and other claims for a furnace susceptible of use in carrying out the process but equally useful in annealing glass or steel articles, the process claim would control. ( ) where a patent claims a specified article of manufacture or other product, and also an instrument for making a part only of that specified article or other product, the product claim, being more intensive, should control the classification; so also in case of a claim for a product and a claim for an instrument performing any minor act with respect thereto. (see rule .) example: where a patent claims a particular construction of a riveted joint, and also a tool for calking the rivet, and where a patent claims a particular construction of shoe, and also a buttonhook for buttoning said shoe, the article and not the tool claims control. ( ) where a patent contains claims to a process and a product, the process claims govern the classification in those cases where search among machines for making the product would have to be made, and such processes would be classifiable on the basis of the mode of operation, usually in the same class with machines for practicing such processes. (see rule .) example: a patent having a claim for a process of making bifocal lenses, consisting in grinding the surface of one piece of glass to form a convex lens, heating another piece of glass until it is plastic, then forcing the ground surface of the first-named piece into the body of the latter and gradually cooling the lens-blank thus formed; and also a claim for a bifocal lens composed of two pieces of glass weld-united, would be classified in glass-manufacture and cross-referenced into lenses. or a patent having a claim to a process of making a metal plate with elongated perforations, consisting in forming round perforations in the plate and subsequently rolling the plate, thereby thinning and elongating the plate and elongating the openings, and also a claim to a metallic plate having relatively long and narrow perforations, would be classified on the basis of the process claim. ( ) where a patent claims both process and product, and the alleged process is disclosed in the product, so that search would have to be made in the appropriate class of products, the product will be adopted as the basis of classification, and classification will be in the appropriate product class. (see rule .) example: a claim for a process of making a pencil consisting in assembling a core of graphite with a sheathing of wood, and attaching a cap of rubber-composition to one end, would be classified as a pencil rather than as a process, became conception of the article is inseparable from the process and search must be made in the article class. ( ) where a patent claims a process of making a composition of matter, and also the composition of matter, the claims will be classified in general in accordance with the classification of the composition of matter in all cases where the process is peculiarly adapted to produce the composition, as by setting forth the introduction or assemblage of particular ingredients, since those processes that include the selection of particular ingredients necessitate search among compositions having such ingredients. (see rule .) example: a patent having a claim for a composition consisting of a mixture of caoutchouc and casein, and a claim for the process of preparing a rubberlike substance which consists in adding undissolved raw caoutchouc to casein and thoroughly mixing and kneading the mass, would be classified according to the composition. ( ) where a patent claims a product such as a specific article of manufacture, or a specific composition of matter, and also claims a process of general application for making one of the parts of the article or one of the ingredients of the composition, the product claim should control the classification. (see rule .) example: if a patent claimed a woven textile fabric having the yarns interlaced in a defined relation, and a process of spinning a yarn utilized in the fabric; or if a patent claimed a varnish composed of shellac, dissolved in wood alcohol, and a pigment, and also contained a claim for distilling wood to obtain the alcohol, the product claim would control the classification in each instance, and the process would be cross-referenced. [ ] all terms have a meaning in extension and in intension. the meaning of a term in extension consists of the objects to which the term may be applied; its meaning in intension consists of the qualities necessarily possessed by objects bearing that name. the term "motors" in extension means all motors--electric, gas, water, spring, weight, etc. "motors" in intension means instruments to convert some form or manifestation of energy into periodical or cyclical motion of a body. as the intension increases the extension decreases, and vice versa. there must be more motors than there are electric motors, and electric motors have more qualifications than are common to all motors. comparison of arts and instruments with respect to their extension and intension for classification purposes should be made between comparable qualities. a claim for a steam-engine may be very specific while a claim for a reaper may be very broad; here there is no comparable relationship, and the terms intensive and extensive do not have the relative significance most useful in classification. but when a patent or application contains claims for mechanism peculiar to electric motors and other claims for mechanism common to electric motors and other kinds of motors, the claims for the electric motor would control the classification. (d) procedure in reclassifying within examining divisions. ( ) do not start to make a new class or revise an old one with preconceived fixed notions respecting its scope and the particular subdivisions required. wait until all patents pertinent to the subject have been seen and adequate knowledge of them acquired. in other words, make no _a priori_ classification but discover and assemble all the facts and from them make your inductions. then the common characteristics of the subject-matter of the class may be intelligently defined, the limitations of the class marked out, and its relation to other classes set forth. bear in mind that the patent office classification deals with the subject-matter of the useful arts rather than merely with existing classes, and that it is not therefore essential to retain classes that are found to be composed of unrelated or too distantly related units. assuming that the work of reclassification is undertaken by examiners who are already experienced in the subject-matter to be classified, procedure as follows is recommended: ( ) utilizing your previously acquired knowledge of the patents in the class you are about to revise, subdivide the existing subclasses into bundles, so as to assemble in each bundle those patents deemed to have the closest resemblance to each other. for the purpose of this assemblage, consider each patent as an entirety and not with reference to various more or less important parts of that entirety. example: an apparatus comprising in alleged combination a means for decanting water, a means for electrolytically depositing impurities, and a means for filtering the water, should not be classified either as a decanter, an electrolytic apparatus, or a filter, but should be classified as a combination apparatus (taking it to the general art of liquid purification). so also the combination of a rotary printing-press with a folding mechanism, and a wrapping mechanism, should not be classified merely as a rotary printing-press, a folding machine, or a wrapping machine, but should be classified as a combination of the several mechanisms as an entirety whose functions carried out in proper order produce a printed and wrapped newspaper. ( ) write an approximate or tentative definition of the matter thus assembled in each bundle and attach it to its appropriate bundle. ( ) where it appears that the subject matter of any bundle formed from the patents of any subclass is analogous to matter in other subclasses of the same class or in other classes, a note should be added to that effect so that this matter may be given special consideration. ( ) when the same examiner or different examiners are working on different subclasses containing analogous matter, parallel lines of subdivision should be followed wherever possible, in order to effect an arrangement that will facilitate comparisons. ( ) when subdividing a group of more or less complex organized structures or mechanisms, note should be taken of subcombinations that form or it is thought should form the basis of other subclasses, either in the same or different classes, into which those details may be collected, either classified therein originally or by cross-reference. example: assuming that the combination of press, folder, and wrapping mechanism, referred to in a preceding paragraph is to be classified in a class of printing, on the entirety as a combination having the function of printing, plus other functions, and that folding and also wrapping are separately classified, then the particular type of press should be selected to be cross-referenced into a press-type subclass of the class of printing, such as "presses, rotary," while the folding mechanism and the wrapping mechanism would be noted for cross-reference to other appropriate classes. also, any part of the printing press, such as the inking mechanism, specifically described, should be noted for cross-reference into a subclass of printing designed to receive the inking mechanism as a part of the printing press. ( ) after a knowledge of the material of the class has been obtained by estimating the resemblances between the individual patents that have been assembled in the several groups, comparison of these groups, represented by the bundles of photolithographs, by the aid of the approximate definitions and notes attached can be made. it can then be decided whether all of these groups are to be retained in the proposed class, and the retained groups can be organized into a class with the subclasses arranged so as to bring those subclasses having the strongest resemblances in closest relation, and in such order as to comply with the conventions adopted in the official classification. it will probably be necessary to have one subclass or group as broad as the definition of the class, to take unclassifiable matter and to provide for possible future inventions. ( ) up to this point, more or less cursory attention may be given individual patents; but when an arrangement of subclasses shall have been tentatively adopted it will be necessary to consider each patent carefully to ascertain whether it is properly placed. ( ) patents that, considered as an entirety, cover means not peculiar to the class or subject-matter being revised, should, in general, when assembled in groups as indicated, have a note attached indicating not only want of limitation to the subject-matter of the class but also a more appropriate class to receive them if such there be. although a very large proportion of patents can be accurately classified as indicated by their titles and stated uses, the mere fact that in a patent found in a class the invention is called in the specification or claims by a name peculiar to the class is not of itself a reason for considering it peculiar to the class. a gas and liquid contact apparatus may be called a heater, a cooler, a gas-washer, a water-carbonator, a condenser, a disinfecter, an air-moistener, and so on, depending upon accident of use. if there are not elements in some claim to confine the means described distinctively to what it is called, or if there are no functions necessarily implied in the means claimed peculiar to the named use, the patent should not be kept in the class unless there is no other class in the office that can receive it. example: where the matter claimed is a metal beam of peculiar cross-section, it should be classified with other metal beams, as in class , metallic building structures, even if it is named in the application as a beam of particular use, as a railroad-tie, car-sill, bridge-tie, etc. should a mere dash-pot be found classified in class , electricity, generation, a note should be attached indicating that it belongs in the appropriate element class. ( ) in giving this final careful attention to the patents, each should also be scanned to see whether it contains matter that should be cross-referenced. a few lines obscurely located in a specification may contain a disclosure of a most valuable invention. no class can be deemed complete until the disclosures appropriate to it found as parts of more complex inventions in other classes, or disclosures of analogous matter in other classes, are either cross-referenced into it or cross search-notes made. ( ) to indicate cross-references, from one subclass to another within the class or from the class under consideration into another class, attach a small slip of paper to the patent and mark on the slip the subclass number in which the cross-reference shall be mounted. if the matter to be cross-referenced relates only to a portion of a voluminous patent, the portion of the specification and drawing to be cross-referenced should be indicated. if the cross-reference falls outside the class, the class number should be noted in addition to the subclass number. ( ) should it be found that the handling of copies in making examinations detaches the cross-reference slips, it may be advisable to mark lightly but legibly in pencil on the lower right-hand corner of the examiner's photolithograph the number of the subclass or subclasses into which it is to be cross-referenced, or the number of the class and subclass in case it is to be cross-referenced to another class. ( ) whether cross-reference notations are written on a separate slip or on the photolithograph, the number of the class and subclass into which a patent is to be cross-referenced should always be preceded by x (thus x - ) in order to distinguish the original classification notation from the cross-reference notation and enable sorting and indexing to be done without confusion. ( ) to indicate cross-references from other classes into the one being reclassified, set down the number of the patent in a notebook, placing after the number ( ) the class and subclass in which it is classified; and ( ) the number of the class and subclass in which it is to be cross-referenced. ( ) should new subclasses be formed or transfers of patents be determined on, and lists of the patents, instead of copies thereof, be furnished clerks for the purpose of making such subclasses and transfers and correcting the official indexes and other records, each patent should be listed by number in column to the left of a sheet of paper or notebook, and opposite each patent number on the same sheet should be written ( ) the number of the class and subclass in which it is officially classified; ( ) the number of the class and subclass to which it is intended to transfer it; and ( ) the numbers of the classes and subclasses, preceded by x, into which it is intended to cross-reference it. note: even though examiners engaged in reclassifying are confident of their ability to classify and arrange on better principles than those that have been applied thus far in the classification, they ought, nevertheless, to follow those principles under which one-half of the patents have been classified. until the commissioner of patents orders examiners to classify on other principles, it is expected they will follow those now established. +-----------------------------------------------------------------+ | transcriber's note: | | | | every effort has been made to replicate this text as faithfully | | as possible, including obsolete and variant spellings and other | | inconsistencies. | | | | for readability, the footnotes have been moved to the end of | | the relevant chapter. | | | +-----------------------------------------------------------------+ proofreading team at www.pgdp.net [illustration] scientific american supplement no. new york, august , scientific american supplement. vol. xxviii., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. agriculture.--how to raise turkeys.--a collection of hints and suggestions on the raising of the delicate fowls, so often the cause of trouble to farmers. pear duchesse d'angouleme.--the history of the famous pear tree, with hints as to its culture and general treatment. ii. biology.--development of the embryo.--a note of some interesting biological researches.--by prof. preyer, of berlin. the "hatchery" of the sun fish.--a curious incident in the life history of the common sunfish.-- illustration. iii. chemistry.--on allotropic forms of silver.--by m. carey lea.--a continuation of this paper, containing one of the most important researches in the history of silver, with statement of interesting results attained. on the occurrence of paraffine in crude petroleum.--a valuable contribution to the history of paraffine, with reference to petroleum and ozokerite. turpentine and its products.--by edward davies.--a resume of the work done by chemists in the turpentine products. --the different compounds produced therefrom. iv. electricity.--electric lighting at the paris exhibition. --the oerlikon works.--a very exhaustive exhibition of electric apparatus described and illustrated.-- illustrations. magnetism in its relation to induced electromotive force and current.--by elihu thomson.--a most impressive paper, bringing the obscure laws of magnetic induction within the understanding of all without the application of mathematics.-- illustrations. the ader flourish of trumpets.--one of the curiosities in telephony from the paris exhibition, by which sounds are transmitted to a large audience.-- illustrations. the electric motor tests on the new york elevated railroad.--abstracts of tests which were recently made of the daft motor on the elevated railroad of this city. v. ethnology.--ancient lake dwellings.--interesting abstract of what is known about lake dwellings, the history of their construction, and the "finds" made on the sites by archæologists. vi. forestry.--succession of forest growths.--a valuable paper on forestry, treating of the evils done by man and a plea for the necessity of intelligent treatment of our woods. vii. hygiene and medicine.--acetic acid as a disinfectant.--use of acetic acid in septic medical cases as a substitute for carbolic acid and bichloride of mercury. counter-irritation in whooping cough.--by g.f. inglott, m.d.--application of irritants to the skin for curing the paroxysms of whooping cough. on the health value to man of the so-called divinely beneficent gift, tobacco.--by j.m.w. kitchen, m.d.--the evils to man and to the soil.--a formidable series of accusations well expressed. water as a therapeutical agent.--by f.c. robinson, m.d.--an interesting resume of different applications of water in therapeutics.--suggestions of use for all households. viii. military engineering.--gibraltar.--a history of this important strategic position and of the different sieges the fortress has undergone. gibraltar and neighborhood.--a consular report on the statistics of the famous military station. the defense of gibraltar--experimental naval and military operations.--interesting series of operations recently carried out under the shadow of the historic rock.-- illustration. ix. naval engineering.--clark's gyroscopic torpedoes.--a recent torpedo, in which all the possible parts are made to rotate.-- illustrations. the first steamboat on the seine.--the marquis de jouffroy's steamer of .-- illustration. the franz josef i., new war ship.--details of the dimensions of the new austrian ship.--her armament, speed, armor, etc. x. photography.--orthochromatic photography.--by oscar o. litzkow.--the last developments in this interesting branch of photographic art, with formulæ. platinotype printing.--a description of the most advanced method of conducting the platinum print process. xi. physics.--iridescent crystals.--by lord rayleigh.--an abstract of a lecture by the distinguished physicist, detailing some interesting experiments applicable to the colored reflection observed in crystals of chloride of potash.-- illustration. transmission of pressure in fluids.--by albert b. porter.--an apparatus for illustrating the laws of transmission of pressure in fluids, suitable for lecture purposes.-- illustration. xii. technology.--notes on dyewood extracts and similar preparations.--by louis siebold.--the recent development in the preparation of dyewood extracts, with notes of their adulterations. * * * * * the defense of gibraltar: experimental naval and military operations. [illustration: the defense of gibraltar--experimental naval and military operations.] a novel and interesting series of operations was carried out at gibraltar a few weeks ago, with a view to test the promptitude with which the garrison of the famous rock could turn out to resist a sudden attack by a powerful iron-clad fleet. the supposed enemy was represented by the channel squadron, under the command of vice-admiral baird, and consisting of h.m.s. northumberland (flag ship), the agincourt, monarch, iron duke, and curlew. the "general idea" of the operations was that a hostile fleet was known to be cruising in the vicinity, and that an attack on the rock might be made. the squadron left gibraltar and proceeded to the westward, returning to the eastward through the straits under cover of the night. the governor of gibraltar, general the hon. sir arthur hardinge, issued orders for the whole garrison to stand to their arms at dawn, and subsequent days, until the attack should be made; but by his express command no batteries were to be manned, or any troops moved from their alarm posts, until the signal was given that an attack was imminent. the alarm signal ordered was that of three guns fired in rapid succession from the upper signal station on the summit of the rock, to be followed, after a short pause, by two more shots. it was a matter of complete uncertainty as to the direction from which the attack would be made. every detail was carefully carried out, as if the impending attack was a real affair. the telegraphic communication between the various parts of the rock was supplemented by signalers; arrangements were made for the ready supply of reserve ammunition for all arms; and the medical authorities established dressing stations, at numerous points of the rock, to render "first aid" to those who might chance to be numbered among the "wounded." day broke with a "levanter," and the heavy clouds hanging about rendered any distant view a matter of difficulty. however, before it had become actually daylight the alarm guns gave notice that the enemy had been sighted. the troops turned out with great promptitude, being all at their assigned stations in less than a quarter of an hour, and were shortly ordered to various points commanding the east side of the rock. as day broke, the hostile ships were to be discerned steaming in single line ahead, from the northeast, along the back of the rock, and about , yards from it. the flag ship, followed by the monarch and the agincourt, proceeded toward europa point, while the iron duke and the curlew stood close in to the eastern beach, so as to engage the northern defenses of the fortress. the first shot was fired by the flag ship, shortly before six o'clock in the morning, at the southern defenses. it was replied to, in less than three minutes, by the europa batteries, and very shortly the engagement became general. the plan of tactics employed by the squadron was that of steaming rapidly up and down, and concentrating their fire in turn on the various shore batteries. later on, the whole squadron assembled off europa point, and fired broadsides by electricity as they steamed past at speed. the spectacle at this moment was a very fine one, the roar of the heavy guns of the ships being supplemented by the sharp, rapid report of the quick-firing guns, which were supposed to be sending a storm of small shell among the defenders of the rock. the incessant rattle of the ships' machine guns was also heard in the intervals between the thundering broadsides of heavy ordnance. all the ships were, of course, cleared for action, with topmasts and yards sent down, and it is needless to say they looked exceedingly workmanlike and formidable. the various batteries on the rock replied with great vivacity, and the general effect produced as gun after gun was brought to bear on the ships, and the white smoke wreathed itself round the many crags and precipices of the grim old rock, was a sight long to be remembered. the exercise afforded to both branches of the service was undoubtedly most instructive. our illustration is a sketch by captain willoughby verner from one of the batteries above the europa flats, at which point the governor took up his position to watch the operations. --_illustrated london news._ * * * * * gibraltar and neighborhood. report by consul sprague. notwithstanding that the political situation of europe seems to be less threatening among its leading powers, still the uncertainty prevalent among those who are generally considered the arbiters of public affairs has had its influence in contracting the limits of speculative adventure, thereby circumscribing the general course of trade throughout the mediterranean. in renewing to the department my reports upon the navigation and general commerce of gibraltar, i beg to state that there has been a tolerably fair current business prevailing in american produce during the past quarter, consisting chiefly in flour, tobacco, and refined petroleum in cases, imported direct from new york. the steady demand for american petroleum confirms the fact that russian petroleum so far receives but little attention in this market from the regular traders and consumers, so long as supplies from the united states can be regularly imported at reasonable prices. it, however, remains an open question, in the event of lower prices ruling in the russian petroleum regions, whether american supplies may not later on experience some greater competitive foreign interference. according to the statistical data, steam vessels of all nationalities have continued to make gibraltar their port of call, not only for orders, but also for replenishing their stock of fuel and provisions, and in larger numbers than ever before, the number in having reached , steam vessels, measuring in all , , tons, while in the number was only , steam vessels, with an aggregate tonnage of , , . this increase cannot but result in considerable benefit to the coal and maritime traffic, which now forms the most important portion of the general commerce of gibraltar, in spite of the keen competition it experiences from other british and foreign coaling ports. freights have also advanced in favor of steamship interests, which, with higher prices in england for coal, have also caused an advance in the price of coal at this port, to the benefit of the coal merchants and others interested in this important trade. at present the ruling price for steam coal is s. per ton, deliverable from alongside of coal hulks moored in the bay. as near as i have been able to ascertain, the quantity of coal sold in this market during the past year for supplying merchant steam vessels has amounted to about , tons, which is an increase of about , tons over the year . notwithstanding that plans have already been submitted to the british government for the construction of a dry dock in gibraltar, the matter remains somewhat in suspense, since it meets with some opposition on the part of the british government, which, in face of the european fever for general arming, seems more inclined to utilize in another form the expense which such a work would entail upon the imperial government, by replacing the obsolete ordnance recently removed from this fortress and substituting new defenses and guns of the most approved patterns, a matter which has evidently been receiving, for some time past, the special attention of the british military authorities, not doubting that the recent visit to the fortress of the duke of cambridge has had some connection with it. in fact, it is reported that the duke has already expressed the opinion that this fortress requires a larger number of artillerymen than are quartered here at present to man its batteries, and it would seem that this recommendation is likely to be carried out. it is yet somewhat too early to venture an opinion regarding the growing crops of cereals in this spanish neighborhood, but the agricultural and manufacturing interests in spain have suffered so much in the past years that the general feeling in spain continues to tend toward establishing increased restrictions against foreign competition in her home markets. there is every probability that the provinces of malaga and granada may shortly be granted the privilege of cultivating the tobacco plant under government supervision, as an essay. if properly managed, it may form an important and lucrative business for those interested in land and agricultural pursuits. after many consecutive years of heavy outlays, difficulties, and constant disappointments, a new english company has recently succeeded in commencing the construction of a railway from the neighboring spanish town of algeciras to join, via ronda, the railway station of bobadilla, on the railroad line toward malaga. it is presumed that when this railroad will be in running order it will greatly benefit this community, especially if the spanish government should decide to establish custom houses at algeciras and the spanish lines outside the gates of this fortress, similar to those existing on the frontiers of france and portugal. that some idea may be formed of the constant important daily intercourse which exists between this fortress and spain, i may state that late police statistics show that , , passes were issued to visitors entering this fortress on daily permits during the year , , , entering by the land route and , by sea. i must, however, observe that the larger portion of these visitors consists of laborers, coal heavers, market people, and others engaged in general traffic. a new industry in cork has lately sprung up, in which leading spanish and native commercial firms in gibraltar are directly interested to a considerable extent. extensive warehouses for the storing of cork wood and machinery for the manufacture of bottle corks have recently been established at the spanish lines, about a mile distant from this fortress, in spanish territory, where large quantities of cork have already been stored. the cork is obtained and collected from the valuable trees, which are owned by the representatives of some of the oldest nobility of spain, who have sold the products of their extensive woods to private individuals for periods reaching as far on as ten years, for which concession large cash advances have already been made. the woods commence at a distance of about twelve miles from gibraltar, and are of considerable extent. the railway now in course of construction passes through these woods, which may ere long offer quite picturesque scenery for travelers, especially when the cork trees are bearing acorns, which form the principal food for the fattening of large herds of swine during certain seasons of the year, in this way, also, contributing to the value of this tree, which, like the other kinds of oak trees, is of long and tardy growth. the tree from which the cork is obtained is somewhat abundant in the mountainous districts of andalusia. it grows to a height of about feet, and resembles the _quercus ilex_, or evergreen oak, and attains to a great age. after arriving at a certain state of maturity it periodically sheds its bark, but this bark is found to be of better quality when artificially removed from the tree, which may be effected without injury to the tree itself. after the tree has attained twenty-five years it may be barked, and the operation is afterward repeated once in every seven years. the quality of the cork seems to improve with the increasing age of the tree, which is said to live over one hundred and fifty years. the bark is taken off during july and august. cork dust is also obtained from this cork wood, and is much used in the packing of grapes, which fruit is largely shipped from the eastern coast of spain, especially from almeria, during the vintage seasons, for the american and british markets.--_reports of u.s. consuls._ * * * * * gibraltar. the point or rock known as gibraltar is a promontory two and one-half miles long and from a quarter to three-quarters of a mile wide. it rises abruptly from the sandy shore to a height at its highest point of , ft. it is composed of gray limestone, honeycombed with caves and subterranean passages, some of which contain most beautiful stalactites in the form of massive pillars. gibraltar is emphatically a fortress, and in some respects its fortifications are unique. on the eastern side the rock needs no defense beyond its own precipitous cliffs, and in all other directions it has been rendered practically impregnable. besides a sea wall extending at intervals round the western base of the rock, and strengthened by curtains and bastions and three formidable forts, there are batteries in all available positions from the sea wall up to the summit, , feet above the sea, and a remarkable series of galleries has been hewn out of the solid face of the rock toward the north and northwest. these galleries have an aggregate length of between two and three miles, and their breadth is sufficient to let a carriage pass. portholes are cut at intervals of twelve yards, so contrived that the gunners are safe from the shot of any possible assailants. at the end of one of the galleries hollowed out in a prominent part of the cliff is st. george's hall, feet long by feet wide, in which the governor was accustomed to give fetes. alterations, extensions, and improvements are continually taking place in the defensive system, and new guns of the most formidable sort are gradually displacing or supplementing the old fashioned ordnance. the whole population of gibraltar, whether civil or military, is subjected to certain stringent rules. for even a day's sojourn the alien must obtain a pass from the town major, and if he wish to remain longer, a consul or householder must become security for his good behavior. licenses of residence are granted only for short periods--ten, fifteen, or twenty days--but they can be renewed if occasion require. military officers may introduce a stranger for thirty days. a special permit is necessary if the visitor wishes to sketch. though the town of gibraltar may be said to date from the fourteenth century, it has preserved very little architectural evidence of its antiquity. rebuilt on an enlarged and improved plan after its almost complete destruction during the great siege, it is still, on the whole, a mean-looking town, with narrow streets and lanes and an incongruous mixture of houses after the english and the spanish types. as a proprietor may at any moment be called upon to give up his house and ground at the demand of the military authorities, he is naturally deterred from spending his money on substantial or sumptuous erections. the area of the town is about one hundred acres. gibraltar was known to the greek and roman geographers as calpe or alybe, the two names being probably corruptions of the same local (perhaps phenician) word. the eminence on the african coast near ceuta, which bears the modern english name of apes' hill, was then designated abyla; and calpe and abyla, at least according to an ancient and widely current interpretation, formed the renowned pillars of hercules (herculis columnæ), which for centuries were the limits of enterprise to the seafaring peoples of the mediterranean world. the strategic importance of the rock appears to have been first discovered by the moors, who, when they crossed over from africa in the eighth century, selected it as the site of a fortress. from their leader, tarik ibn zeyad, it was called gebel tarik or tarik's hill; and, though the name had a competitor in gebel af futah, or hill of the entrance, it gradually gained acceptance, and still remains sufficiently recognizable in the corrupted form of the present day. the first siege of the rock was in , when it was taken by alonzo perez de guzman for ferdinand iv. of spain, who, in order to attract inhabitants to the spot, offered an asylum to swindlers, thieves, and murderers, and promised to levy no taxes on the import or export of goods. the attack of ismail ben ferez, in (second siege), was frustrated; but in vasco paez de meira, having allowed the fortifications and garrison to decay, was obliged to capitulate to mahomet iv. (third siege). alphonso's attempts to recover possession (fourth siege) were futile, though pertinacious and heroic, and he was obliged to content himself with a tribute for the rock from abdul melek of granada; but after his successful attack on algeciras in he was encouraged to try his fortune again at gibraltar. in he invested the rock, but the siege (fifth siege) was brought to an untimely close by his death from the plague in february, . the next or sixth siege resulted simply in the transference of the coveted position from the hands of the king of morocco to those of yussef iii. of granada; and the seventh, undertaken by the spanish count of niebla, enrico de guzman, proved fatal to the besieger and his forces. in , however, success attended the efforts of alphonso de arcos (eighth siege), and in august the rock passed once more under christian sway. the duke of medina sidonia, a powerful grandee who had assisted in its capture, was anxious to get possession of the fortress, and though henry iv. at first managed to maintain the claims of the crown, the duke ultimately made good his ambition by force of arms (ninth siege), and in the king was constrained to declare his son and his heirs perpetual governors of gibraltar. in ferdinand and isabella made the second duke marquis of gibraltar, and in the third duke, don juan, was reluctantly allowed to retain the fortress. at length, in , garcilaso de la vega was ordered to take possession of the place in the king's name, and it was formally incorporated with the domains of the crown. after ferdinand and isabella were both dead the duke, don juan, tried in to recover possession, and added a tenth to the list of sieges. thirty-four years afterward the garrison had to defend itself against a much more formidable attack (eleventh siege)--the pirates of algiers having determined to recover the rock for mahomet and themselves. the conflict was severe, but resulted in the repulse of the besiegers. after this the spaniards made great efforts to strengthen the place, and they succeeded so well that throughout europe gibraltar was regarded as impregnable. in the course of the war of the spanish succession, however, it was taken by a combined english and dutch fleet under sir george rooke, assisted by a body of troops under prince george of hesse-darmstadt. the captors had ostensibly fought in the interests of charles archduke of austria (afterward charles iii.), but, though his sovereignty over the rock was proclaimed on july , , sir george rooke on his own responsibility caused the english flag to be hoisted, and took possession in name of queen anne. it is hardly to the honor of england that it was both unprincipled enough to sanction and ratify the occupation and ungrateful enough to leave unrewarded the general to whose unscrupulous patriotism the acquisition was due. the spaniards keenly felt the injustice done to them, and the inhabitants of the town of gibraltar in great numbers abandoned their homes rather than recognize the authority of the invaders. in october, , the rock was invested by sea and land; but the spanish ships were dispersed by sir john leake, and the marquis of villadarias fared so ill with his forces that he was replaced by marshal tesse, who was at length compelled to raise the siege in april, . during the next twenty years there were endless negotiations for the peaceful surrender of the fortress, and in the spaniards again appealed to arms. but the conde de la torres, who had the chief command, succeeded no better than his predecessors, and the defense of the garrison under general clayton and the earl of portmore was so effectual that the armistice of june practically put a close to the siege, though two years elapsed before the general pacification ensued. the most memorable siege of gibraltar, indeed one of the most memorable of all sieges, was that which it sustained from the combined land and sea forces of france and spain during the years - . the grand attack on the place was made on the th september, , and all the resources of power and science were exhausted by the assailants in the fruitless attempt. on the side of the sea they brought to bear against the fortress forty-six sail of the line and a countless fleet of gun and mortar boats. but their chief hope lay in the floating batteries planned by d'arcon, an eminent french engineer, and built at the cost of half a million sterling. they were so constructed as to be impenetrable by the red hot shot which it was foreseen the garrison would employ; and such hopes were entertained of their efficiency that they were styled invincible. the count d'artois (afterward charles x.) hastened from paris to witness the capture of the place. he arrived in time to see the total destruction of the floating batteries and a considerable portion of the combined fleet by the english fire. despite this disaster, however, the siege continued till brought to a close by the general pacification, february , . the history of the four eventful years' siege is fully detailed in the work of drinkwater, who himself took part in the defense, and in the life of its gallant defender sir george augustus eliott, afterward lord heathfield, whose military skill and moral courage place him among the best soldiers and noblest men whom europe produced during the th century. since the history of gibraltar has been comparatively uneventful. in the beginning of there were rumors of a spanish and french attack, but the spanish ships were defeated off algeciras in june by admiral saumarez. improvements in the fortifications, maintenance of military discipline, and legislation in regard to trade and smuggling are the principal matters of recent interest. * * * * * the franz josef i., new war ship. another addition was made to the austrian navy by the launching on may of the ram cruiser franz josef i. from the yards of s. rocco in the stabilimento tecnico triestino. her dimensions are: length (over all), . meters; length (between perpendiculars), . meters; greatest breadth (outside), . meters; draught (bow), . meters; draught (stern), . meters; displacement on the construction water line, , tons. the armament consists of two -centimeter and six -centimeter krupp breech loaders of caliber length, two -centimeter uchatius guns as an armament for the boats and for landing purposes, eleven hotchkiss quick-firing guns, and several torpedo-launching ports; indicated horse power with natural draught , , speed . knots; with forced draught , , speed knots. the ship is built of steel, and constructed according to the "double bottom" system along the engine, boiler, and ammunition rooms. the vaulted armor deck, extending . meters below the water line and protecting the most vital parts of the ship, is . meter thick. there are more than water tight compartments below and above the deck. a protecting belt of "cellulose" is provided for the engines and boilers, extending from the armor deck downward. the two main guns, placed on krupp's hydraulic carriages, occupy positions in front and rear, and are protected by stands . meter thick and . meters high. they fire _en barbette_ with a lateral range each of degrees at bow and stern--i.e., degrees on either of the broadsides. the weight of the barrel of the gun is tons, that of the steel shell kilogrammes (about lb.), that of the brown powder charge kilogrammes; initial velocity of projectile, meters; penetration, . meter iron; longest range, kilometers (about ½ english miles); range at deg. elevation, kilometers. the six -centimeter guns are placed in a kind of machicouli arrangement in two tiers on each of the broadsides, so that always four guns can fire in the direction of the keel to the front and rear. the weight of the barrel of the gun is each six tons, that of the steel shells kilogrammes, that of the charge kilogrammes; initial velocity, meters. the quick-firing guns are partly placed along the broadsides, partly in the masts, of which there are two. the triple expansion engines, having each a bronze screw of . meters diameter, with three blades and a rise of . meters, make with natural draught revolutions, and with forced draught . the pumping apparatus are able to lift in one hour tons of water. the front boiler room contains a special cylindrical boiler for the working of the electrical apparatus, for hydraulic pumps of the artillery service, for anchor windlasses, ventilators, fire engines, etc. the whole engines weigh tons. the bunkers have a capacity for tons of coal, which allows for a run of , sea miles. * * * * * clark's gyroscopic torpedoes. figs. and represent, upon a scale of about / , two types of torpedoes, the greatest number possible of the parts of which are made revolvable, so as to render the torpedoes as dirigible as the gyrating motion permits of. fig. represents an electric torpedo actuated by accumulators, a a, keyed upon the shaft, and revolving along with the gearings. at the beginning of the running, the accumulators are not all coupled, but under the action of a clockwork movement which is set in motion at the moment of starting, metallic brushes descend one after another upon the collectors, b, and set in action new batteries for keeping constant or, if need be, accelerating the speed at the end of the travel. [illustration: fig. .] [illustration: fig. . clark's gyroscopic torpedoes.] fig. represents an air torpedo proposed by the same inventor. the air reservoir, c, revolves along with the gearings under the action of the pneumatic machine, d. the central shaft is hollow, so as to serve as a conduit. the admission of air into the slide valve of the machine is regulated by a clockwork which actuates a slide in an aperture whose form and dimensions are so calculated that the speed remains as constant as possible toward the end of the travel. the trajectory of the two torpedoes is regulated by a cylindrical bellows, f, which gives entrance to the sea water. the springs shown in the figure balance the hydraulic pressure. the tension of these springs is regulated by the rod, h, according to the indications of the scale of depths, i. when the torpedo reaches too great a depth, the action of the springs can no longer balance the increase of the hydraulic pressure, and the accumulation of the charge in the rear causes the front to rise toward the surface. when the torpedo reaches the surface, a contrary action is produced.--_revue industrielle._ * * * * * the first steamboat on the seine. [illustration: first steamboat built on the seine.] the accompanying engraving represents the remarkable steamboat that the unfortunate marquis de jouffroy constructed at paris in , after organizing a company for the carriage of passengers on the seine. de jouffroy, as well known, made the first experiment in steam navigation at lyons in , but the inventor's genius was not recognized, and he met with nothing but deception and hostility. with the obstinacy of men of conviction, he did not cease to prosecute his task. he assuredly had an inkling of the future in store for the invention that he was offering to humanity. the paddle wheel boat that he constructed at paris in did not succeed any better than its predecessors; it was remarkable nevertheless in appearance and structure. the engine was forward, as shown in the engraving, which is copied from a composition of dubucourt's. the company organized by the marquis was ruined, and, as well known, the unfortunate inventor himself died in poverty in , at the age of eighty-one years.--_la nature._ * * * * * the electric motor tests on the new york elevated railroad. the american institute of electrical engineers at its last meeting of the season, held june , again considered the subject of electrical traction, the paper presented by mr. leo daft being based upon some recent electrical work on the elevated railroads and its bearing on the rapid transit problem. the _railroad gazette_ gives the following abstract: he introduced the subject with a tribute to the efficiency of the elevated railroad system as it is now operated by steam, with special reference to that section of it known as the ninth avenue line, upon which his experiments with the electric motor have been conducted, over which passengers are now conveyed a distance of five miles in minutes for five cents, which he considered the best and cheapest municipal rapid transit in the world, and which is operated with a higher degree of safety than any other railroad in the world making an equal number of stops per miles. on a recent holiday, april last, , passengers were carried upon the entire system without noticeable detention or accident. the rapidly increasing traffic makes the demand for better facilities a pressing one, and as the average half million now carried daily will soon become a million, it appears doubtful if any method can be devised of providing for the growth by the use of steam motors on the present structures, which are now taxed to their utmost. to the mind of the mechanical engineer, having in view the ordinary coefficients of tractive ability, there is no remedy for this. the speaker stated that these coefficients were not entirely trustworthy. he reiterated his previously expressed opinion, based on frequent experiments, that there is a decided increase in traction gained by the passage of the electric current from the wheels to the rails, giving the details of one test where a motor with a load making a total of lb. climbed a gradient of , ft. per mile, starting from a state of rest. he stated that some of those people who had ridiculed his statements had finally admitted that they were true. the motor ben franklin, which had been used in making these tests on the elevated roads, weighed tons, and performed service nearly equal to the steam motors weighing tons. the object of these tests was the determination of coal economy. tests with a prony brake showed that the motor developed h.p. the piece of track on which the experiments were conducted embraced , ft. of level track and - / miles of gradients, varying from - / to - / ft. per mile, while at thirtieth street the station is at the foot of the steepest grade, thus testing to the utmost the tractive capacity of the motor. the experiments were begun in october, , and carried on between the hours of p.m. and a.m., beginning with one or two cars, the load being increased nightly until it was finally made up of eight coaches of tons each, which were hauled up the ft. grade at a speed of ½ miles per hour, the entire distance being covered at the rate of - / miles per hour. the maximum speed obtained on level with that train was . miles per hour. seventy trips were subsequently made with a ton train operated between the steam trains under minutes headway, but the work was considered too critical on account of the absence of suitable brakes. a number of experiments made about this time showed that the mean speed with a three-car train running express on the up-town track was about miles per hour, although the ability of the motor on a level with a similar train was nearly miles per hour. this, however, was not the maximum speed, as the level track was not long enough to permit of its attaining the highest rate. it was the opinion of the speaker, however, that the speed attained could not be exceeded with prudence on the elevated structure. the measurements of speed were made by dividing the track into sections of ft., each section being provided with a circuit-closing plate connected with a chronograph which was carefully tested. the indicator cards were taken at the central station by mr. idell and his assistants, and the dynamometer used was of the liquid type made by mr. shaw, of philadelphia. the diagrams prepared from the data obtained were then explained by the speaker, who stated that there was not a marked difference between the ton motor and the ton locomotive in the initial effort on the level, as will be seen by comparing a run observed by a railroad officer on march with a steam motor and a load of about ½ tons. the steam motor required min. and sec. to make the distance from th to d streets, while the electric motor with a train of tons made the same trip in min. and sec.; the absence of power brakes compelled the current to be taken off at th street, while it was probable that the throttle of the steam locomotive was not closed until it reached d street, this being the usual practice. the data obtained in these experiments shows that , h.p. is required to operate the ninth avenue railroad for the hours' service, or an average of , h.p. per hour, or , h.p., adding station friction. the varying requirements of the traffic during the day shows that the service could be advantageously divided up between four stationary engines of h.p. each, there being but five hours of the day when all of them would be required. the fuel consumption per day, allowing lb. of coal per h.p. per hour at $ . per ton, would make a total of $ . per diem for fuel, the coal being a mixture deliverable at the dock for about $ . per ton. the weight of coal used for the present locomotives is about the same, viz., tons per day, but practice has shown it to be most economical to use coal of the best quality, costing $ per ton, making the cost of fuel about double that required for the electric system. without entering into other economies which the speaker claimed were in favor of electricity, and ignoring the plan suggested by sir william siemens of braking the train by converting the motor into a dynamo and thus utilizing the energy of momentum, he believed that the economy in fuel alone was sufficient to prove that the application of power by electricity was preferable to direct steam propulsion for the elevated railroad service. * * * * * magnetism in its relation to induced electromotive force and current.[ ] [footnote : a paper read before the american institute of electrical engineers, new york, may , .] by elihu thomson. there is perhaps no subject which at the present time can have a greater interest to the physicist, the electrician, and the electrical engineer than the one which heads this paper. the advances which have been made in the study from its purely theoretical or scientific side, and the great technical progress in the utilization of the known facts and principles concerning magnetic inductions, can but deepen and strengthen that interest. on the side of pure theory we find the eager collection of experimental data to be submitted to the scrutiny of the ablest and brightest minds, to be examined and reasoned upon with the hope of finding some clew to satisfying explanations, and on the side of practice we find the search for new facts and relations no less diligent, though often stimulated by practical problems presented for solution. indeed, the urgency for results is often the greater on the practical side, for theory can wait, practice cannot, at least in the united states. we must look for continued triumphs in both directions, and the most welcome of all will be the framing of a theory or explanation which will enable us to interpret magnetic and electric phenomena. the recent beautiful experiments of hertz on magnetic waves have opened a fertile region for investigation. it would seem that the study of magnetism and electricity will give us the ability to investigate the ether of space, which medium has been theorized upon at great length, with the result of leaving it very much where it was before, a mysterious necessity. faraday says, speaking of magnetism: "such an action may be a function of the ether, for it is not at all unlikely that if there be an ether it should have other uses than simply the conveyance of radiations." , . vol. iii., exp. res. "it may be a vibration of the hypothetical ether, or a state of tension of that ether equivalent to either a dynamic or a static condition," etc. , . vol. iii., exp. res. faraday again says, speaking of the magnetic power of a vacuum: "what that surrounding magnetic medium deprived of all material substance may be i cannot tell, perhaps the ether." , . vol. iii., exp. res. modern views would seem to point that through a study of magnetic phenomena we may take a feeble hold upon the universal ether. magnetism is an action or condition of that medium, and it may be that electrical actions are the expression of molecular disturbances brought about by ether strains or interferences. the close relations which are shown to exist between magnetism and light tend to strengthen such views. indeed, it would not be too much to expect that if the mechanics of the ether are ever worked out, we should find the relation between sensible heat and electric currents to be as close as that of light to magnetism, perhaps find ultimately the forms of matter, the elements and compounds to be the more complex manifestations of the universal medium--aggregations in stable equilibrium. it is a difficult conception, i confess, and a most shadowy and imperfect one, yet facts and inferences which favor such views are not wanting. our science of electricity seems almost to be in the same condition that chemistry was before the work of lavoisier had shed its light on chemical theory. our store of facts is daily increasing, and apparently disconnected phenomena are being brought into harmonious relation. perhaps the edifice of complete theory will not be more than begun in our time, perhaps the building process will be a very gradual one, but i cannot refrain from the conviction that the intelligence of man will, if it has time, continue its advance until such a structure exists. i have been led to make these general allusions to electrical theory in order to emphasize the fact that in the present paper no unraveling of the mystery is to be attempted, but rather the presentation of some few considerations upon a subject of absorbing interest. the conception of faraday in regard to the existence of lines of magnetic force representing directions of magnetic strain or tension in a medium has not only lost nothing of its usefulness up to the present time, but has continually been of great service in the understanding of magnetic phenomena. we need spend no time in showing, as faraday and others have done, that these lines are always closed circuits, polarized so that the direction of the lines cannot be reversed without reversal of the actions. nor need we take time to show that in any medium the lines are mutually repellent laterally if of the same direction of polarization. opposing this tendency to separation or lateral diffusion of magnetic force is the strong apparent tendency of the lines to shorten themselves in any medium. these actions are distributed by the presentation of a better medium, as iron instead of space or air. lines of force will move into the better medium, having apparently the constant tendency to diminish the resistance in their paths. the peculiar and mysterious nature of media, such as iron, is to permit an extraordinary crowding of lines on account of slight resistance to their passage through it. we need not, in addition, do more than refer to the other well-known facts of an electric current developing magnetic lines encircling the conductor, as being the general type, which includes all forms of magnetic field or electro-magnets, sustained by currents, and the fact of a development when magnetic lines or circuits and material masses are in relative movement of electromotive forces transversely to the direction of the lines of magnetism, and also transversely to the direction of relative movement, as in the case of electric conductors traversing or cutting through a field, or of a field traversing or being moved across a conductor. we must not forget that even insulators, as well as conductors, cutting lines of force, have the electromotive force developed in them. the action simply develops potential difference, and this generates the current where a circuit exists. while we are in the habit of saying that a conductor moved across a field of lines, or _vice versa_, generates electric current, i think the statement incomplete. the movement only sets up a potential difference, and the power expended in effecting the movement generates c × e. the current is energy less the potential, or the energy expended gives the two effects of potential or pressure and current or rate of movement. consequently an insulator, or an open-circuited conductor, traversing a field, consumes no energy, potential difference only being produced. nevertheless, as will be shown, the magnetic circuits or lines themselves may furnish the energy for their own movement across a conductor, and so develop current as well as potential. this occurs in the effort of lines to shorten their paths, to lessen their density, to pass to better media. indeed, a close examination will show that wherever power is expended in developing current in a circuit, cutting lines of force, the energy expended is first employed in stretching the lines, which thus receive the energy required to permit them, in shortening, to cut the conductor and set up currents in the electric circuit in accordance with the potential difference developed in that circuit and its resistance. i think we may also say, though i do not remember to have seen the statement so put, that whenever electric potential is set up inductively, as in self-induction, mutual induction, induction from one circuit to another, and induction from magnets or magnetic field, it is set up by the movement of lines of force laterally across the body, mass or conductor in which the potential is developed, and that whenever current is set up in a wire or an existing current prolonged, or an existing current checked by induction, self-induction, or induction from magnets, the action is a transfer of energy, represented by strained lines of force shortening or lessening their resistance, or lengthening and increasing the resistance in their paths. the magnetic field is like an elastic spring--it can in one condition represent stored energy--it can be strained and will store energy--it can be made to relieve its strain and impart energy. [illustration: fig. .] let us examine some known phenomena in this light. take the case of a simple wire, conveying current, say, in a line away from observer, fig. . there exists a free field of circular magnetism (so called), shading off away from the wire, and which is represented by concentric circles of increased diameter. the superior intensity or strength of the lines near the wire may also be represented by their thickness. this is often shown also by crowding the lines near the wire, though i am disposed to regard fig. as more nearly expressing the condition, unless we are to regard the lines as simply indicating a sort of atmosphere of magnetic effect whose density becomes less as we proceed outward from the wire, in which case either form of symbol suffices. the direction of polarization of the lines may be indicated by an arrow head pointing in a direction of right-handed rotation in the path of the lines. this is the typical figure or expression for all forms of simple magnetic circuit--the form of the lines, their length, position, density, will depend on the shape of the conductor or conductors (when more than one) and the materials surrounding or in proximity to the wire or wires. if the current traversing the conductor is constant, the magnetic field around it is stable and static, unless other influences come in to modify it. the cutting off of the current is followed by instability of the field whereby it can and must produce dynamic effects. i say _must_ because the field represents stored energy, and in disappearing _must_ give out that energy. to throw light on this part of the subject is one of the objects of the present paper. cutting off the current supply in the case assumed leaves the developed magnetic lines or strains unsupported. they at once shorten their paths or circuits, collapsing upon the conductor as it were, and continuing this action, cut the section of the conductor, and apparently disappear in magnetic closed circuits of infinitesimal diameter but of great strength of polarization. it appears to me that we must either be prepared to give up the idea of lines of force or take the position that the magnetic circuits precipitate themselves in shortening their circuits and disappearing upon and cut the conductor. it was hughes who put forward the idea that an iron bar in losing its apparent magnetism really short-circuits the lines in itself as innumerable strongly magnetized closed circuits among the molecules. in becoming magnetic once more these short circuits are opened or extended into the air by some source of energy applied to strain the lines, such as a current in a conductor around the bar. may not this idea be extended, then, to include the magnetic medium, the ether itself? does it contain intensely polarized closed circuits of magnetism which are ready to be stretched or extended under certain conditions by the application of energy, which energy is returned by the collapse of the extended circuits? this is doubtless but a crude expression of the real condition of things, for the lines are only symbols for a condition of strain in a medium which cannot be represented in thought, as we know nothing of its real nature. there is one point in this connection which i must emphasize. the strained lines, fig. , are indications of stored energy in the ether, and the lines _cannot_ disappear without giving out that energy. ordinarily, it makes its appearance as the extra current, and adds itself so as to prolong the current which extended the lines when an attempt is made to cut off such current. were it conceivable that the current could be cut off and the wire put on open circuit while the lines still remained open or strained, the energy must still escape when the field disappears. it would then produce such a high potential as to be able to discharge from the ends of the conductor, and if the conductor were of some section, part of the energy would be expended in setting up local currents in it. the field could not disappear without an outlet for the energy it represents. but we cannot cut off a current in a wire so as to leave the wire on open circuit with the lines of the magnetic circuit remaining around it without iron or steel or the like in the magnetic circuit. we can approach that condition, however, by breaking the circuit very quickly with a condenser of limited capacity around the break. this is done in the ruhmkorff coil primary; the condenser forms a sort of blind alley for the extra current on its beginning to flow out of the primary coil. but the condenser charges and backs up and stops the discharge from the primary, even giving a reverse current. the lines of magnetic force collapse, however, and have their effect in the enormous potential set up in the secondary coil. take away the secondary coil so as to stop that outlet, the energy expends itself on the iron core and the primary coil. take away the iron core, and the energy of magnetization of the air or ether core expends itself on the wire of the primary and, possibly, also on the dielectric of the condenser to some extent. the extra current becomes in this instance an oscillatory discharge of very high period back and forth through the primary coil from the condenser, until the energy is lost in the heat of c × r. this conversion is doubtless rendered all the more rapid by uneven distribution of current and eddy current set up in the wire of the coil. the considerations just given concern the loss of field or the shortening and apparent disappearance of the magnetic lines or circuits, as giving rise to the self-induction or increased potential on breaking. where the energizing current is slowly cut off or diminished the energy is gradually transferred to the wire in producing elevation of potential during the decrease; and the collapse and cutting of the wire by the collapsing circuits or lines is then only more gradual. let the current be returned to the wire after disappearance of magnetism, and the lines again seem to emanate from the wire and at the same time cut it and produce a counter potential in it, which is the index of the abstraction of energy from the circuit, and its storing up in the form of elastically strained lines of magnetism around the conductor. the effect is that of self-induction on making or upon increase of current, the measure of the amount being the energy stored in the magnetic circuits which have been extended or opened up by the current. the greater the current and the shorter the path for the lines developed around the axis of the conductor, the greater the energy stored up. hence, a circular section conductor has the highest self-induction, a tube of same section less as its diameter increases, a flat strip has less as its width increases and thickness diminishes, a divided conductor much less than a single conductor of same shape and section. separating the strands of a divided conductor increases the length of magnetic paths around it, and so diminishes the self-induction. a striking instance of this latter fact was developed in conveying very heavy alternating currents of a very low potential a distance of about three feet by copper conductors, the current being used in electric welding operations. the conductors were built up of flat thin strips of copper for flexibility. when the strips were allowed to lie closely together, the short conductor showed an enormous self-induction, which cut down the effective potential at its ends near the work. by spreading apart the strips so as to lengthen a line around the conductor, the self-induction could be easily made less than per cent. of what it had been before. the interweaving of the outgoing and return conductor strands as one compound conductor gets rid almost entirely of the self-inductive effects, because neither conductor has any free space in which to develop strong magnetic forces, but is opposed in effect everywhere by the opposite current in its neighbor. where a number of conductors are parallel, and have the same direction of current, as in a coil or in a strand, it is evident that statically the conductor may be considered as replaceable by a single conductor with the same external dimensions and same total current in the area occupied, the magnetic forces or lines surrounding them being of same intensity. but with changing current strength the distribution of current in the conductor has also a powerful effect on the energy absorbed or given out in accordance with the magnetism produced. hence the self-induction of a strand, coil or conductor of the same section varies with the rapidity of current changes, owing to the conduction being uneven. the uneven distribution of current, or its tendency to flow on the outer parts of a conductor when the rate of variation or alternation is made great, is in itself a consequence of the fact that less energy is transferred into magnetism in this case than when the current flows uniformly over the section, or is concentrated at the center. in other words, when a uniform current traverses a conductor of the same section, the circular magnetism, or surrounding magnetic lines, are to be found not only outside the conductor, but also beneath its exterior. since in forming these lines on passage of current the middle of section would be surrounded by more lines than any other part of the conductor, the current tends to keep out of that part and move nearer the exterior in greater amount. hence, in rapidly alternating currents the conductor section is practically lessened, being restricted largely to the outer metal of the conductor. if the round conductor, fig. , were made of iron, the magnetism interior to it and set up by a current in it would be very much greater, the section of the conductor being filled with magnetic circuits or lines around the center. the total magnetism, external and internal, would be much greater in this case for a given current flow, and the energy absorbed and given out in formation and loss of field or the self-induction would be much increased. this could, however, be greatly diminished by slitting the conductor radially or making it of a number of separate wires out of lateral magnetic contact one with the other, fig. . in these cases the resistance of the interior magnetic circuits would be increased, as there would be several breaks in the continuity around the center of the conductor. the total magnetism which could be set up by a current would be lessened, and the self-induction, therefore, lessened. [illustration: fig. .] [illustration: fig. .] the moment we begin the bringing of iron into proximity with an electric conductor conveying current, we provide a better medium for the flow or development of magnetic lines or circuits. in other words, the lines may then be longer, yet equally intense, or more lines may be crowded into a section of this metal than in air or space. figs. a, b, c show the effect brought about by bringing iron of different forms near to the conductor. [illustration: fig. a.] [illustration: fig. b.] [illustration: fig. c.] it shows, in other words, the development of the ordinary electro-magnet of the horseshoe form, and the concentration of the lines in the better medium. the lines also tend to shorten and diminish the resistance to their passage, so that attraction of the iron to the conductor takes place, and if there is more than one piece of iron, they tend to string themselves around the conductor in magnetic contact with one another. when copper bars of inch diameter are traversed by currents of , to , amperes, as in welding them, the magnetic forces just referred to become so enormous that very heavy masses of iron brought up to the bar are firmly held, even though the current be of an alternating character, changing direction many times a second. [illustration: fig. ] [illustration: fig. ] when a conductor is surrounded by a cast iron ring, as in fig. , the current in such conductor has an excellent magnetic medium surrounding it. a large amount of energy is then abstracted on the first impulse of current, which goes to develop strong and dense magnetic lines through the iron ring and across the gap in it. on taking off the current the energy is returned as extra current, and its force is many times what would be found with air alone surrounding the conductor. we have then greatly increased the self-induction, the storing of energy and opposition to current flow at the beginning, the giving back of energy and assistance to the current flow on attempting to remove or stop the current. let us now complete the ring, by making it of iron, endless, fig. , with the conductor in the middle. we now find that on passing current through the conductor it meets with a very strong opposing effect or counter potential. the evolution of magnetic lines, or the opening out of magnetic circuits, goes on at a very rapid rate. each line or magnetic circuit evolved, and cutting the conductor, flies at once outward, and locates itself in the iron ring. this ring can carry innumerable lines, and they do not crowd one another. it permits the lines even to lengthen in reaching it, and yet, on account of its low resistance to their passage, the lengthening is equivalent to their having shortened in other media. we will suppose the current not sufficient to exhaust this peculiar capacity for lines which the iron has. equilibrium is reached, the conductor has opened up innumerable closed circuits, and caused them to exist in the ring still closed; but in iron, not space or ether merely. the current passing has continued its action and storage of energy until to emit another line in view of the resistance now found in the crowded iron ring is impossible. now let us cut off the current. we are surprised to find a very weak extra current, a practical absence of self-induction on breaking, or, at least, a giving out of energy in nowise comparable to that on making. let us put on the current as it was before. another curious result. but little self-induction now on making energy not absorbed. now cut off the current again. same effect as before. now let us put on the current reversed in direction. at once we find a very strong counter potential or opposing self-induction developed. the ring had been polarized, or retained its magnetic energy, and we are now taking out one set of lines and putting in reversely polarized lines of force. this done, we break the reversed current without much effect of self-induction. the ring remains polarized and inert until an opposite flow of current be sent through. iron is then a different medium from the ether. the ring once magnetized must, in losing its magnetism, permit a closure of the lines by shortening. this involves their passage from the iron across the space in the center of the ring, notwithstanding its great resistance to the lines of force. as passage from iron to air is equivalent to lengthening of the lines, it is readily seen that such lengthening may oppose more effect than a slight shortening due to leaving iron, for air or space may give in provoking a closure and disappearance of the lines. looked at from another standpoint, the lines on the iron may actually require a small amount of initial energy to dislodge them therefrom, so that after being dislodged they may collapse and yield whatever energy they represent. i must reserve for the future further consideration of the iron ring, but in thinking upon this matter i am led to think that the production of a magnetic line in an iron ring around a conductor may represent a sort of wave of energy, an absorption of energy on the evolution of the line from the conductor, and a slight giving out of energy on the line reaching that position of proximity to the iron ring, that its passage thereto may be said to be a shortening process or a lessening of its resistance. the magnetism in air, gases, and non-magnetic bodies, being assumed to be that of the ether, this medium shows no such effects as those we get with the ring. it does not become permanently polarized, as does even soft iron under the condition of a closed ring. the iron possesses coercive force, or magnetic rigidity, and a steel ring would show more of it. the molecules of the iron or steel take a set. if we were to cut the soft iron ring, or separate it in any way, this introduction of resistance of air for ether in the magnetic circuit would cause the lines to collapse and set up a current in the conductor. the energy of the ring would have been restored to the latter. the curious thing is that physically the polarized ring does not present any different appearance or ordinary properties different from those of a plain ring, and will not deflect a compass needle. its condition is discoverable, however, by the test of self-induction to currents of different direction. as a practical consideration, we may mention in this connection that a self-inductive coil for currents of one direction must be constructed differently from one to be used with alternating currents. the former must have in its magnetic circuit a section of air or the like, or be an imperfectly closed circuit, as it were. the latter should have as perfectly closed a magnetic circuit as can be made. we see here also the futility of constructing a ruhmkorff core coil on the closed iron magnetic circuit plan, because the currents in the primary are interrupted, not reversed. the considerations just put forward in relation to the closed iron ring, and its passive character under the condition of becoming polarized, are more important than at first appears. it has been found that the secondary current wave of a closed iron circuit induction coil or transformer, whose primary circuit receives alternating current, is lagged from its theoretical position of degrees behind the primary wave an additional degrees, so that the phases of the two currents are directly opposed; or the secondary current working lamps only in its circuit is one half a wave length behind a primary, instead of a quarter wave length, as might have been expected. but when it is understood that the iron core polarized in one direction by the primary impulse does not begin to lose its magnetism when that impulse simply weakens, but waits until an actual reversal of current has taken place, it will be seen that the secondary current, which can only be produced when magnetic lines are leaving the core and cutting the secondary coil, or when the lines are being evolved and passing into the core from the primary coil, will have a beginning at the moment the primary reverses, will continue during the flow of that impulse, and will end at substantially the same time with the primary impulse, provided the work of the secondary current is not expended in overcoming self-induction, which would introduce a further lag. moreover, the direction of the secondary current will be opposite to that of the primary, because the magnetic circuits which are opened up by the primary current in magnetizing the core, or which are closed or collapsed by it in demagnetizing the core, will always cut the secondary coil in the direction proper for this result. transformers of the straight core type with very soft iron in the cores and not too high rates of alternation should approximate more nearly the theoretical relation of primary and secondary waves, because the magnetic changes in the core are capable of taking place almost simultaneously with the changes of strength of the primary current. this fact also has other important practical and theoretical bearings. let us assume a plain iron core, fig. , magnetized as indicated, so that its poles, n, s, complete their magnetic circuits by what is called free field or lines in space around it. let a coil of wire be wound thereon as indicated. now assume that the magnetism is to be lost or cease, either suddenly or slowly. an electric potential will be set up in the coil, and if it has a circuit, work or energy will be produced or given out in that circuit, and in any other inductively related to it. hence the magnetic field represents work or potential energy. but to develop potential in the wire the lines must cut the wire. this they can do by collapsing or closing on themselves. the bar seems, therefore, to lose its magnetism by gaining it all, and in doing so all the external lines of force moving inward cut the wire. the magnetic circuits shorten and short-circuit themselves in the bar, perhaps as innumerable molecular magnetic circuits interior to the iron medium. to remagnetize the bar we may pass an electric current through the coil. the small closed circuits are again distended, the free field appears, and the lines moving outward cut across the wire coil opposite to the former direction and produce a counter potential in the wire, and consequent absorption of the energy represented in the free field produced. as before studied, the magnetism cannot disappear without giving out the energy it represents, even though the wire coil be on open circuit, and therefore unable to discharge that energy. the coil open-circuited is static, not dynamic. in such assumed case the lines in closing cut the core and heat it. let us, however, laminate the core or subdivide it as far as possible, and we appear to have cut off this escape for the energy. this is not really so, however. we have simply increased the possible rate of speed of closure, or movement of the lines, and so have increased for the divided core the intensity of the actions of magnetic friction and local currents in the core, the latter still receiving the energy of the magnetic circuit. this reasoning is based on the possibility in this case of cutting off the current in the magnetizing coil and retaining the magnetic field. this is of itself probably impossible with soft iron. that the core receives the energy when the coil cannot is shown in the well known fact that in some dynamos with armatures of bobbins on iron cores, the running of the armature coils on open circuit gives rise to dangerous heating of the cores, and that under normal work the heating is less. in the former case the core accumulates the energy represented in the magnetic changes. in the latter the external circuit of the machine and its wire coils take the larger part of the energy which is expended in doing the work in the circuit. in this case, also, the current in the coils causes a retardation of the speed of change and extent of change of magnetism in the iron cores, which keeps down the intensity of the magnetic reaction. in fact, this retardation or lag and reduction of range of magnetic change may in some machines be made so great by closing the circuit of the armature coils themselves or short-circuiting them that the total heat developed in the cores is much less than under normal load. [illustration: fig. .] i wish now, in closing, to refer briefly to phenomena of moving lines of force, and to the effects of speed of movement. in order to generate a given potential in a length of conductor we have choice of certain conditions. we can vary the strength of field and we can vary the velocity. we can use a strong field and slow movement of conductor, or we can use a weak field and rapid movement of the conductor. but we find also that where the conductor has large section it is liable to heat from eddy currents caused by one part of its section being in a stronger field than another at the same time. one part cuts the lines where they are dense and the other where they are not dense, with the result of difference of potential and local currents which waste energy in heat. we cannot make the conductor move in a field of uniform density, because it must pass into and out of the field. the conditions just stated are present in dynamos for heavy current work, where the speed of cutting of lines is low and the armature conductor large in section. but we find that in a transformer secondary we can use very large section of conductor, even (as in welding machines) to square inches solid copper, without meeting appreciable difficulty from eddy currents in it. the magnetic lines certainly cut the heavy conductor and generate the heavy current and potential needed. what difference, if any, exists? in the transformer the currents are generated by magnetic field of very low density, in which the lines are moving across the conductor with extreme rapidity. the velocity of emanation of lines around the primary coil is probably near that of light, and each line passes across the section secondary conductor in a practically inappreciable time. there is no cause then for differences of potential at different parts of the section heavy secondary. then to avoid eddy currents in large conductors and generate useful currents in them, we may cause the conductor to be either moved into and out of a low density field with very great speed, or better, we must cause the lines of a very low or diffused field to traverse or cut across the conductor with very high velocity. it is a known fact that, in dynamos with large section armature conductors, there are less eddy currents produced in the conductors when they are provided with iron cores or wound upon iron cores than when the conductors are made into flat bobbins moved in front of field poles. projections existing on the armature between which the conductors are placed have a like effect, and enable us to employ heavy bars or bundles of wire without much difficulty from local currents. the reason is simple. in the armatures with coils without iron in them, or without projections extending between the turns, the conductor moves into and out of a very dense field at comparatively low velocity, so that any differences of potential developed in the parts of the section of conductor have full effect and abundant time to act in setting up harmful local currents. in the cases in which iron projects through the coil or conductor, the real action is that the lines of the magnetic circuits move at high speeds across the conductor, and the conductor is at all times in a field of very low density. figs. and will make this plain. in fig. we have shown a smooth armature surface, having a heavy conductor laid thereon, and which is at a just entering a dense field at the edge of the pole, n, and at b leaving such field. it will be seen that when in such position the conductor, if wide, is subjected to varying field strength, and moves at a low speed for the generation of the working potential as it passes through the field, thus giving rise to eddy currents in the conductor. [illustration: fig. .] in fig. the conductors are set down between projections, in which case both armature and field poles are laminated or subdivided. as each projection leaves the edge of field pole, n, the lines which it had concentrated on and through it snap backward at an enormous speed, and cross the gap to the next succeeding projection on the armature, cutting the whole section of the heavy armature conductor at practically the same instant. this brisk transfer of lines goes on from each projection to the succeeding one in front of the field pole, leaving a very low density of field at any time between the projections. the best results would be obtained when the armature conductor does not project beyond or quite fill the depth of groove between the projections. of course there are other remedies for the eddy current difficulty, notably the stranding and twisting of the conductor on the armatures so as to average the position of the parts of the compound conductor. [illustration: fig. .] perhaps the most extreme case of what may be called dilution of field by projections and by closed magnetic circuits in transformers would be that of a block of iron, b, fig. , moved between poles, n and s, and having a hole through it, into and through which a conductor is carried. the path through the iron is so good that we can scarcely consider that any lines cross the hole from n to s; yet as b moves forward there is a continual snapping transfer of lines from the right forward side of the hole to the left or backward side, cutting the conductor as they fly across, and developing an electromotive force in it. i have described this action more in detail because we have in it whatever distinction in the manner of cutting the lines of the field is to be found between wire on smooth armatures and on projection armatures and modifications thereof; and also between flat, open coils passing through a field and bobbins with cores of iron. the considerations advanced also bring out the relation which exists between closed iron circuit transformers and closed iron circuit (projection) dynamos, as we may call them. [illustration: fig. .] i had intended at the outset of this paper to deal to some extent with the propagation of lines of magnetism undergoing retardation in reference to alternating current motor devices, transformers with limited secondary current, or constant average current, an alternating motor working with what i may term a translation lag, etc.; but it was soon found that these matters must remain over for a continuation of this paper at some future time. my endeavor has been in the present paper to deal with the lines of force theory as though it were a symbol of the reality, but i confess that it is done with many misgivings that i may have carried it too far. yet, if we are to use the idea at all it has seemed but right to apply it wherever it may throw any light on the subject or assist in our understanding of phenomena. * * * * * electric lighting at the paris exhibition--the oerlikon works. immediately on entering the machinery hall by the _galerie_ leading from the central dome, and occupying a prominent position at the commencement of the swiss section, is a very important plant of dynamos, motors, and steam engines, put down by the oerlikon works, of zurich. during the time the machinery is kept running in the hall, power is supplied electrically to drive the whole of the main shafting in the swiss section and part of that in the belgian section, amounting in all to some ft., a large number of machines of various industries deriving their power from these lines of shafting, while during the evening a portion of the upper and lower galleries adjoining this section is lit by some twenty-five arc lamps run from this exhibit. steam is supplied from the roser boilers in the motive power court. the whole of the generating plant is illustrated in one view, and a separate view is given of the motor employed to drive the main shafting, this latter view showing the details of connection to the same. on the extreme right hand side of the first view is a direct coupled engine and dynamo of horse power, a separate cut of which is given in fig. . the engine is of the vertical single cylinder type, standing ft. high, and fitted, as are the other two engines exhibited, with centrifugal governor gear on the fly wheel, acting directly on the throw of the cutoff valve eccentric. the two standards, supporting the cylinder and forming the guide bars, together with the entire field magnets and pole pieces of the dynamo, and the bed plate common to both, are cast in one piece. [illustration: fig. engine and dynamo for steamships.] the machine is specially designed for ship lighting, and with the view of preventing any magnetic effect upon the ship's compass, the field is arranged so that the armature, pole pieces, and coils are entirely inclosed by iron. any tendency to leakage of magnetic lines will therefore be within the machine, the iron acting as a shield. this build of field--shown in fig. a--is also advantageous as a mechanical shield to the parts of the machine most likely to suffer from rough handling in transport, and it will be seen that the field coils are easily slipped on before the armature is mounted in its bearings. [illustration: fig. a] the winding is compound, and in such a direction that the two opposite horizontal poles have the same polarity; it follows from this that there will be two consequent poles in the iron, these being opposite in name to the horizontal poles and at right angles to them, viz., above and below the armature. opposite sections of the commutator are connected together internally as in most four-pole machines, so that only two brushes are necessary, at deg. apart. the section of iron in the field is square inches and rectangular in form, and the whole machine measures ft. in. in length, and ft. in height, without including the height of the bed plate. the armature is in. in length and the same in diameter, measured over the winding, and develops at the machine terminals volts and amperes at revolutions. the moving parts of the engine are well balanced, and run remarkably well and without noise at this high rate of speed. this dynamo serves to develop power to run a motor in an adjoining inclosure, containing some fine specimens of lathes and machine tools constructed by the oerlikon works. these are driven by the motor through the medium of a countershaft, and the power and speed are controlled from the switch board seen at the left of the exhibit, and in fig. . the resistance, r , serves to vary the intensity of the shunt field of the dynamo, the volts being indicated by the voltmeter v , and a resistance separate from the switch board is inserted in the main circuit of the two machines. the ammeter, a , is directly connected to the dynamo, and therefore indicates the current, whatever circuit this machine is running. [illustration: figs. - , plus the paris exhibition--stand of the oerlikon works.] a larger combined engine and dynamo, seen in the center of the stand, serves to run the lighting of the galleries. the engine is a horse power compound, running at revolutions, and fitted with a governor on the fly wheel, like that described above. the dynamo is a two-pole machine, the upper pole and yoke being cast in one, and the lower pole, yoke, and combined bed plate forming a separate casting. the two vertical cores, over which the field bobbins are slipped, are of wrought iron, and are turned with a shoulder at either end, the yokes being recessed to fit them exactly. the cores are then bolted to the yokes vertically from the top and horizontally below. the field of this machine is shunt-wound, and in order to maintain the potential constant a hand-regulated resistance--r on the switch board--is added in circuit with the shunt field. the voltmeter, v , immediately above this resistance, serves to indicate the difference of potential at the machine terminals. both voltmeters are fitted with keys, so that they are only put in circuit when the readings are taken. the main terminals of this machine are fitted on substantial insulating bases, fixed one at each end of the top yoke. these connect to the external circuit by a heavy cable--the machine being capable of developing amperes--and to the shunt circuit, and regulating resistance by small wires; while the two connections to the brushes are by four covered wires in parallel on each side. this mode of connection is more flexible than a short length of heavy cable, and looks well, the wires being held neatly together by vulcanized fiber bridges. the dynamo is a low tension machine, the field being regulated to give volts when running the lamp circuits. [illustration: fig. .] the illustration, fig. , represents the automatic re-regulator--c.e.l. brown's patent. motion is imparted to the cores of two electro-magnets at the ends by the pulleys, w w . the cores have a projection opposite to the spindle, ab, which latter is screw-threaded. by a relay one or other electro-magnet is put in action, and the rotating core, which is magnetized, causes rotation of the spindle by attraction, resulting in the movement of the contact along the resistance stops. the relay is acted upon directly by the potential of the dynamo, and the variable resistance is included in the shunt field of the machine, so that changes in the potential, resulting from changes in load or speed, are compensated for. the arrangements of the lamp circuits and the lamp itself may now be described. the lamps are all run in parallel circuit, but are divided into groups of five, each group being controlled by a separate switch on the board--figs. and a. these switches are not in direct communication with the dynamo, but make that connection through a large central switch, s , which therefore carries the whole current. the returns from each group are brought to the connections seen between the two resistances, where the circuits may be disconnected if desired, and the main current then passes through the ammeter, a , to the other terminal of the machine. one of the smaller switches at the top, fig. a, is directly connected with one terminal of the horse power dynamo before mentioned, and the other side of the switch to the motor in the machine tool exhibit. also one of the switches in connection with the central switch, s , is connected to the same motor, and therefore the latter may be run by either machine, or, in fact, any combination of machines, lamps, and motor be made as required. the form of switch made by the oerlikon works is illustrated in fig. . two thick semicircular bands of copper are screwed at one end to opposite sides of a square block which is turned round by the switch handle. the block has a projection at each corner, and two strong, flat, stationary springs are attached to the framework of the switch and press on opposite sides of the block. the ends of the springs engage in the projections and prevent the switch being turned round the wrong way, while the pressure of the springs on opposite sides forces the copper bands to take up a position exactly in line with the terminal contacts when the switch is closed, or at right angles to them when it is opened. [illustration: fig. a] [illustration: figs. , b and c] further, each lamp has its own separate adjustable resistance, fuse, and switch. these are of special construction, combined in one, and are illustrated in figs. and a; the other figures, b and c, showing some of the details of the same. the wires, w w, lead from and to one lamp. the current enters at one wire, passes through the fuse, f--figs. c and a--down the center of the cylinder to a divided contact, into which a switch arm can be shot. when this is so, a connection is made to the upright brass rod, t, which serves to grip the band, r, passing round the body of the cylinder. the current then passes through all the turns of wire above the band, and out at the other terminal. the resistance can be varied by raising or lowering the band. fig. b shows the manner of tightening the band against the wires on the cylinder. the upright rod, t, is seen in section, and is fixed in one position to the frame of the apparatus. abutting against this, and working in the block to which the two ends of the band are screwed, is a thumb screw, s, by turning which the band may be loosened for adjusting, and tightened when the right position is found. the cylinder is covered with asbestos sheet, and the wire, which is of nickel, and measures altogether from to ohms, is wound helically round this. the switch arm, to which the handle is attached below, does not itself make and break the circuit, but carries a spring, as shown, which, when the arm is at the end of its movement, pulls over the contact lever with a rapid action, shooting the same between the divided contact piece, and making a perfect contact. the switchboard forms one side of a closed wooden case or cupboard, with sufficient room for a man to enter and adjust the resistances or switches for each lamp. these are screwed to the inside of the case in rows, to the number of twenty-five. the greatest care has been taken in the fixing of the connections to the inside of this case, and no leading wires of different potential are allowed to cross each other. [illustration: fig. a] the oerlikon lamp, which is designed to work with constant potential, is shown partly in section in fig. . there is only one solenoid, a, through which all the current passes, and whose action is to strike the arc and maintain the current constant. the soft iron core, c, is suspended from the inside of the tube, t, in which it has an up and down movement checked by an air piston in the tube. an end elevation of the brake wheels and solenoid is given in fig. , where it will be seen that the spindle carrying these wheels also carries between them a pinion engaging with the rack rod, r. the top carbon attached to the rack rod falls by its own weight, and is therefore in contact with the lower carbon before the lamp is switched in circuit. when this is done the core is instantly magnetized, and attracted to the soft iron brake wheels, which it holds firmly. the air cushion in the tube prevents the core being drawn up until it has fairly gripped the sides of the wheels. the subsequent raising of the core therefore turns the wheels, raises the rack rod, and strikes the arc. the feed is operated by the weakening of the magnetic field of the coil, which causes the core to lose its grip of the wheels, and allows the top carbon to descend. the catch, l, fig. , has a lateral play, and serves to engage in the teeth of the rack rod, so as to prevent its falling when being trimmed. each carbon when in position is held against two rectangular guide bars by the pressure of a wire spring--see figure. in this way the carbon is pressed against two parallel knife edges, and is therefore always in true alignment. the action of the lamp is very simple, the working parts are few and solidly constructed, and the regulation, as exhibited by the lamps running in the galleries, is exceptionally steady. the transmission of power plant consists of two horse power dynamos--c.e.l. brown's patent--the generator being driven by a vertical compound condensing engine of the same power, running at revolutions. the dynamo generator is a four-pole volt direct current machine, series wound, and may be distinguished in the engraving next to the switch board; while the motor receiver connected to it, and erected in another portion of the swiss section, is of exactly the same size and type. the field, which is hexagonal in shape, is cast in two pieces, bolted together horizontally, the cross-sectional area of iron being square inches. the armature is cylindrical, and built up of flat rings stamped out of soft sheet iron, eight notches in the same being provided to fit over the arms of the spider keyed to the shaft. the spider is in halves, which are bolted together longitudinally after the rings are in position. it is gramme wound, and measures over the winding in. radial depth, in. outside diameter, and in. in length. the current is collected by four brushes. the fitting and mechanical build of the dynamos leaves nothing to be desired. all the working parts of the dynamos and engines are turned up to gauge and template, so as to be interchangeable. as an instance of this, the armature of the generator was built in the works, while the field magnets were being erected in the exhibition, and, on arrival, fitted in position perfectly, and ran at once without trouble. the energy taken off on the motor shaft is close on horse power, but varies according to the machines at work; the speed of the motor does not, however, vary more than per cent., and the brushes need no adjustment. about ft. of shafting is coupled on in line with the motor shaft, and an extra plummer block fixed at the end. this shafting carries at its extremity an additional ft. pulley, the power being delivered by belting from these pulleys to two large pulleys on the main shaft. the machines run by this transmission consist of the looms of rieter & co., of winterthur; the large flour mill and lift of a. millot & co.; the flour milling machinery of frederick wegmann & co., of zurich; the brick and tile making machines of the rorschach foundries; and the looms of messrs. houget & teston, of verviers, in the belgian section. a horse power two-pole oerlikon dynamo is also run by a belt from the main shaft, and generates power to drive a motor of similar type in the swiss section of the upper gallery. this runs a length of countershafting supplying power to three silk-weaving machines constructed by benninger frères; six weaving machines from the ruti works, near zurich; and one knitting machine exhibited by edward dubied & co., of couvet. the dynamo and motor are connected to the main cable by switches of the type shown in fig. . these are specially designed to destroy the extra current on breaking circuit by the formation of an arc which gradually increases the resistance till the break occurs, rendering it less sudden. one wire passes through the handle and makes contact with the springs, and the other is attached to the clamp in which the carbon rod is held. the current is made to enter at the carbon rod, so that the arcs formed cause consumption of the carbon. a magnetic cut-out--fig. --is also provided to each machine; this consists of an electro-magnet, through which the main current passes, provided with side pole pieces. a flat soft iron plate armature is hinged so as to come up against the pole pieces when attracted. when the current is not sufficiently strong to cause the plate to be attracted, a hole in the center of the latter engages over a small projection in the top of a weighted arm hinged in the center of the board, and keeps it upright. if now the current exceeds the limits of safety to the machine, due to a too heavy load being thrown on, the armature is attracted and releases the vertical arm, which falls over and enters with considerable force between the two spring contacts below. these contacts are connected to the field terminals, which are, therefore, short-circuited, and prevent the dynamo generating any current. a retractile spring can be adjusted to cause cut-off at any required current. these details are indicated in our illustrations mounted on their respective switch boards. since the erection of plant by these works at solothurn for transmitting horse power five miles distant, which attracted so much interest some time ago, several important works have been carried out. among these we may mention a horse power transmission at ½ kilom. distance to a cotton mill at derendingen in switzerland, a horse power transmission at ½ kilom. distance, carried out for gaetano rossi at piovene in italy, and a horse transmission at kilom. distance installed for giovanni rossi, in which the power is given off at two different stations.--_the engineer._ * * * * * the ader flourish of trumpets. although telephonic novelties are not numerous at the universal exposition, telephony--that quite young branch of electric science--is daily the object of curious and interesting experiments which we must make known to our readers, a large number of whom were not yet born to scientific life when the experiments were made for the first time at paris in ; and it is proper to congratulate the société générale des téléphones on having repeated them in to the great satisfaction of the rising generation. we allude to the ader system of telephonic transmissions of sounds in such a way that they can be heard by an audience. the essential parts of this mode of transmission consist of two distinct systems--transmitters and receivers. [illustration: fig. .--the ader flourish of trumpets] the transmitters are four in number, and are actuated by the same number of musicians, each humming into them his part of the quartet (fig. ). this transmitter, represented apart in elevation and section in fig. , is identical with the one used in the curious experiment with the singing condenser. at a is a mouthpiece before which the musician hums his part as upon a reed pipe. he causes the plate, b, to vibrate in unison with the sound that he emits, and this produces periodical interruptions of varying rapidity between the disk, b, and the point, c. the button, d, serves to regulate the distance in such a way that the breakings of the circuit shall be very complete and produce sounds in the receivers as pure as allowed by this special mode of transmission, in which all the harmonics are systematically suppressed in order to re-enforce the fundamental. [illustration: fig. .--details of the transmitter.] this transmitter interrupter is interposed in the circuit of a battery of accumulators, with the five receivers that it actuates, in such a way that the four transmitters and five receivers form in reality four groups of distinct autonomous transmission, the accordance of which is absolutely dependent upon that of the artists who make them vibrate. the five receivers are arranged over the front door of the telephone pavilion, near the eiffel tower (fig. ). each consists of a horseshoe magnet provided, between its branches, with two small iron cores having a space of a few millimeters between them (fig. ). each of these soft iron cores carries a copper wire bobbin, n, the number of spirals of which is properly calculated for the effect to be produced. opposite the vacant space left by the two cores, there is a small piece, t, of rectangular form, and also of soft iron, fixed to a vibrating strip of firwood, l, of about inches section. the periodical breaking of the circuit produced by the transmitter causes a variation in the magnetization of the iron cores of the five receivers and makes the firwood strips vibrate energetically. these vibrations are received and poured forth as it were in front of the telephone pavilion, by large brass trumpets arranged in front of each receiver, as shown in fig. . [illustration: fig. .--the ader flourish of trumpets] it would be difficult for us to pass any judgment whatever upon the musical and artistic value of these transmissions of trumpet music to a distance; we prefer to confess our incompetency in the matter. but it is none the less certain that these experiments are having the same success that they had at their inception in at the universal exposition of electricity, and they allow us to foresee that there is a time coming in which it will be possible to transmit speech to a distance with the same intensity that the present trumpet flourishes have. although all the tentatives hitherto made in this direction have not given very brilliant results, we must not despair of attaining the end some day or other. less than fifteen years ago the telephone did not exist; now it covers the world with its lines.--_la nature._ [illustration: fig. .--details of the receiver.] * * * * * notes on dyewood extracts and similar preparations. by louis siebold, f.i.c., f.c.s. during the last ten years there has been an enormous increase in the production of these preparations, and the time will come when their application in dyeing and calico printing will become so general as to completely supersede the employment of the raw materials. the manufacture of these extracts, to be thoroughly successful, requires to be so conducted as to secure the perfect exhaustion of the dyewoods without the slightest destruction or deterioration of the coloring matters contained in them; and though nothing like perfection has been reached in the attainment of these objects, it is certain that the processes of extraction and evaporation now employed by the best makers are a very great improvement on the older methods. indeed, there is no difficulty nowadays in procuring dyewood extracts of high excellence if the consumer is willing to pay a price for them corresponding to their quality, and knows how to avail himself of the aid of chemical skill to control his purchases. unfortunately, however, there is so much hankering after cheap articles, and so little care is taken to ascertain their real quality, that every scope is afforded to the malpractices of the adulterer. there are many dye and print works in which large quantities of these extracts are used without being subjected to trustworthy tests. moreover, much of the testing is done by fallacious methods and often by biased hands. so fallacious, indeed, are some of these tests, that grossly adulterated extracts are often declared superior to the purer ones, the cause of this being the application of an insufficient proportion of mordant in the dyeing or printing trials, and the consequent waste of the excess of coloring matter in the case of the purer preparation. professional analytical chemists have hitherto given but little attention to these preparations, and the employment of experienced chemists in works is as yet far from general. the testing of dyewood extracts in such a manner as to throw full light on their purity, the quality of raw material from which they are prepared, their exact commercial value their suitability for special purposes, and the proportion and nature of any adulterants they may contain, is of course a difficult and tedious task, and must be left to the expert who is in possession of authentic specimens prepared by himself of all the different extracts made from every variety and quality of raw materials, and who combines a thorough knowledge of experimental dyeing and printing with a large experience in the chemical investigation of these preparations. but when the object of the testing is merely careful comparison of the sample in question with an original sample or previous deliveries, the case is much simplified, and comes within the scope of the general chemist or the laboratory attached to works. a few years ago i recommended carefully conducted dyeing trials on woolen cloth mordanted with bichromate of potash as the best and simplest mode adapted to such cases, and my subsequent experience enables me to confirm that observation to the fullest extent. most of these extracts contain the coloring matter in two states, the developed and the undeveloped, and an oxidizing mordant such as bichromate of potash causes the latter as well as the former to enter completely into combination with a metallic base; whereas many of the other mordants, such as alumina or tin compounds, merely take up the developed portion of the coloring matter together with such small and variable proportions of the undeveloped as might undergo oxidation during the process of dyeing. i would therefore suggest dyeing trials with alumina, tin, iron, etc., only as subsidiary tests indicating the suitability of an extract for certain special purposes, while recommending the trial with bichromate of potash as the one giving the best information respecting the actual strength of the extract in relation to the raw material from which it was obtained, and as giving a fair idea of the money value of the sample. cotton dyeing does not, as a general rule, afford a good means of assaying extracts, as it is generally done under conditions which do not admit of complete exhaustion of the dye bath, but it might often with advantage be resorted to as an additional trial throwing further light on the degree of oxidation or development of the coloring matter. printing trials are apt to give fallacious results unless the proportion of mordant is carefully adjusted to the amount of coloring matter present, and several trials with different proportions would be necessary to prevent erroneous conclusions. for the trials with bichromate of potash on wool i would recommend pieces of cloth weighing about grains, and the most suitable proportion of bichromate of potash is per cent. of the weight of the cloth. the requisite number of pieces (equal to the number of samples to be tested) should be thoroughly scoured and then heated in the bichromate solution at or near the boiling point for not less than ½ hours, after which they should be well washed and then dyed separately in the solutions of equal weights of the extracts at the same temperature and for the same length of time; grains of extract is a suitable quantity for a first trial under these conditions. these trials can then be repeated with different relative proportions of extract in order to ascertain what weight of a sample would give the same depth of color as grains of the standard example. many precautions are required both in the mordanting and dyeing processes in order to obtain trustworthy results; and though the trials with bichromate of potash give the most reliable information of any single test, they should be supplemented by the subsidiary tests already alluded to, and also by a chemical examination, in order to obtain a knowledge, not merely of the wood strength, but also of the general nature of the extract. an adulteration with molasses or glucose can be best determined by fermentation in comparison with a pure sample. mineral adulterants may, of course, be detected by an estimation and analysis of the ash, after making due allowances for variations due to differences in different kinds of the same dyewoods. the estimation of the individual coloring matters in these extracts by means of a chemical analysis is under all circumstances a task requiring much experience, especially as the coloring principles are associated in different qualities of each class of dyewood with different proportions of other constituents which often give much trouble to the unpracticed experimenter. extracts made from logwood roots are now largely manufactured and often substituted or mixed with the extracts of real logwood, and have in some instances been palmed of as logwood extracts of high quality. the correct determination of such admixtures, like the fixing of anything like the exact commercial value of dyewood extracts, requires nothing less than a complete chemical investigation coupled with numerous dyeing trials in comparison with standard preparations, and should be left to an expert. the presence in dyewood extracts of coloring matters in various stages of development has hitherto militated against their use in place of the raw materials by many dyers and printers who are still employing inherited and antiquated processes in which the whole of the coloring matter is not rendered available. it is often asserted by these that even the best of extracts fail to give anything like the results attained by the use of well-prepared woods, and that, indeed, their application proves a complete failure. such failure, however, is simply due to the want of chemical knowledge on the part of the dyers, for there is no real difficulty in making any good and pure extract serve all the purposes for which the woods were used. it is to be hoped that in this branch of industry, as well as in many others, the employment of chemists will become more general than at present, and not be restricted, as is often the case, to young men without experience and without the trained intellect so essential to success in chemical investigations. high class chemical skill is of course available to the manufacturer, but the man of science who brings matured knowledge and valuable brain work into the business required social as well as pecuniary recognition, and the sooner and more fuller this fact is appreciated the better it will be for the maintenance and progress of our industries. with regard to the astringent extracts, such as sumac, myrabolam, divi, valonia, quebracho, oak, etc., it is the aim of the manufacturer, whenever such extracts are intended for the purposes of dyeing and printing, to obtain the tannin in a form in which it is best calculated to fix itself upon the fiber. the case is somewhat different when the same extracts are required for tanning. for this purpose it is necessary that the extract shall have considerable permeating power, and that the tannin contained in it shall readily yield leather of the desired texture, color, and permanency. extracts specially suited for this purpose are by no means always the most suitable for the dyer, and _vice versa_. a brief description of the processes by which the astringent extracts may be tested with particular reference to their fitness for definite purposes concluded the paper. with regard to the question as to whether experimental dyeing with bichromate of potash should be employed as a test even in works where all the dyeing was done with other mordants, he was decidedly of opinion that it should always be resorted to as one of the tests, inasmuch as it was the only simple and expeditious method giving a fair idea of the actual wood strength and money value of the extract. the test should, in such cases, be supplemented by dyeing trials with the mordants used at the works, and, if necessary, also by a chemical analysis. printing trials were not necessarily bad tests, since oxidizing was usually added in these where it was necessary, and any undeveloped coloring matter would thus be oxidized during the steaming process: but, as he had stated before, it was essentially necessary in such cases to have a fair idea of the amount of actual coloring matter in the extract and to adjust the proportion of mordant accordingly. such trials should therefore be preceded by carefully conducted dyeing trials with bichromate of potash. mr. thomson had raised the question whether it would not be well for the manufacturer to prepare these extracts in such a manner that they would contain all the coloring matter in one condition only, in order to insure greater uniformity in their quality and mode of application. this would, no doubt, be a desirable step to take if the owners of dye and print works were more in the habit of availing themselves of the service of competent chemists experienced in this branch, for then they would be able to make any extract do its full work irrespective of the state of development of the coloring matter. such, however, was not the case, and it was a very common thing for the consumer of dyewood extracts to require the manufacturer to prepare them specially for him so as to suit his own dyeing recipes, or in other words to give exactly the same shades, weight for weight, by his own method of dyeing as the article he was in the habit of using. the manufacturer was thus often compelled to make many different qualities of the same extract to suit different customers. for the same reason adulterated articles were often preferred to the pure ones. there was, perhaps, no branch of industry in which chemical skill of a high order could be applied with greater advantage than in dyeing, and nowhere was this fact less recognized. some of the processes of dyeing were exceedingly wasteful and stood in much need of improvement. he (mr. siebold) knew a large works in which a ton of logwood extract was used daily for black dyeing only, and he might safely assert that of this enormous quantity only a very small proportion would be fixed on the fiber, while by far the greater proportion was utterly wasted. such a waste could only be prevented by a searching investigation of its causes by trained skill. mr. thomson had further alluded to the color obtained with logwood or logwood extract and wool mordanted with bichromate of potash, and seemed to be under the impression that the color thus obtained was not black, but blue. this was undoubtedly the case in dyeing trials performed as tests, as these were conducted purposely with a very small proportion of coloring matter in order to admit of a better comparison of the resulting depth of shades. but with larger proportions of logwood the color obtained was a fine bluish-black, and with the addition of a small proportion of fustic or quercitron bark to the logwood a jet black was readily produced. with regard to mr. watson smith's observation as to fractional dyeing, he (mr. siebold) did not regard this method as a suitable trial for ascertaining the strength of an extract, but he admitted it was occasionally very valuable for detecting an admixture of extracts of other dyewoods, such as quercitron bark extract in logwood extract. it was also a good method of ascertaining the speed of dyeing and hence the relative proportion of fully developed coloring matter of an extract.--_jour. soc. chem. industry._ * * * * * orthochromatic photography.[ ] [footnote : read before the photographic association of brooklyn.] by oscar o. litzkow. what i want to show is the manner in which the process has been tested. my employer, mr. bierstadt, has given me permission to show you some samples, and also his chart containing the spectrum colors: violet, indigo blue, green, yellow, orange, red, and black. this chart has been photographed in the orthochromatic and also in the ordinary way. there are many ways of producing an orthochromatic effect; one is the use of a glass tank placed behind or in front of the lens, in which a coloring matter from either a vegetable or mineral product is placed; this tank or cell is, however, only for use in the studio, as for outdoor photography we have a colored glass screen, so as not to be bothered with carrying colored solution. the tank is constructed as follows: procure two pieces of best white plate glass, about inches square; between these place a piece of rubber of the same size square, and about / of an inch thick. in the center of this rubber cut out a circle about inches diameter, and from one of the corners to the center of the circle cut out a narrow strip ¼ inch wide; this serves as the mouth of the tank. the two pieces of glass and the rubber are cemented together with rubber cement; then, to hold it firmly together, two brass flanges are used as a clamp, with four screws at an equal distance apart; a thin sheet of rubber is on the glass side of the flanges to prevent direct contact with the glass, the center remaining clear for the rays of light to pass through solution and glass. one of the best orthochromatic effects made through this tank is with a three-grains-to-the-ounce solution of bichromatic of ammonia or bichromate of potassium. in this method there is no preparation used on the plate. a common rapid dry plate is exposed through this solution; the exposure, however, is about twenty times longer than it would be if you removed the tank with the yellow solution, or, in other words, if a dry-plate is exposed one minute without the yellow solution it would have to be exposed twenty minutes through a three-grain solution of bichromate of potassium or ammonia. it produces wonderful results on an oil painting or any highly colored object. another method, and the one best adapted for landscapes, is to bathe the plate in erythrosine and then expose it through a yellow glass screen. as an illustration, suppose we have before us a beautiful landscape. in the foreground beautiful foliage, in the center a lake, in the distance hills, with a bluish haze appearing pleasing to the eye, also a nice sky with light clouds. now make a plain negative, and see what has become of your clouds, hills, and the distance--not visible! some photographers have been led to think that by underexposing they retain the distance, but they sacrifice the foreground; besides, it does not produce an orthochromatic effect. but it is a good idea to expose longer on the foreground than you do on the distance. this can be done by raising the cap of the lens skyward and gradually shut off, giving the foreground more exposure. plates are prepared for orthochromatic work as follows: take any ordinary rapid dry plate, place it in a bath containing distilled water c.c. strong liquid ammonia c.c. rock it for two minutes, work as dark as you possibly can. now take it out, and place it in the second bath for one and one-fourth minutes and keep it rocking. have on hand for use a stock solution of distilled water , parts. erythrosine "y" brand part. prepare second bath as follows: erythrosine stock solution c.c. distilled water c.c. strong water ammonia c.c. after removing the plate, dip it again face down to rinse off any particles of scum, etc., that may get in the bath accidentally. this bath may be used for one dozen by , when it should be thrown away and fresh bath used. after the plates come out of the last bath, they should be stood on clean blotting paper to absorb the excess of solution. i would also advise to use clean fingers. pyro. or hypo. on the fingers is a drawback to success. after plates have been drained, place them in a cleaned rack in an absolutely light-tight closet, with air holes so constructed as to admit air but no light; the plates will dry in from eight to twelve hours. they are best prepared in the evening, and, if the closet is good, will be dry in the morning. after the plates are dry they may be packed face to face with nothing between them, in a double-cover paper box, and put in a dark closet free from sulphureted hydrogen gas, until ready for use. i have kept plates for three months in this way, and they were in good condition. great care should be used in developing these plates, as they are sensitive to the red; get used to developing in a dark part of the dark room; occasionally you may look at the process of development in a little stronger light. the exposure through the yellow screen with an erythrosine plate is about the same as if you had no orthochromatic plate--a plain plate instead--provided you are not using too dark a yellow on your screen. this can only be determined by experience. i will give to a common plate about four seconds, an orthochromatic plate under the same conditions five seconds. the yellow glass screen is prepared as follows: take a piece of best plate glass--common cannot be used--clean it nicely; take another large plate glass, or anything that is level and true, level it with a small spirit-level. now take the cleaned piece of glass and coat it with aurentia collodion. ether oz. alcohol oz. cotton grs. the aurentia to be added to suit your judgment; it takes a very small quantity to make an intense yellowish-red collodion. pour it on the center of the glass, flow it to the edges, and before it sets place it on the level glass and allow it to set; when set put it in a rack to dry. should it dry in ridges, the collodion may be too thick, and it must be thinned down with equal parts of alcohol and ether. a single piece of plate glass, about one-eighth inch thick, coated with aurentia collodion, is all that is required with an erythrosine plate. or, after a piece has been successfully coated, another piece of the same plate glass, and the same size, may be cemented together with balsam, having the coated aurentia side between the two glasses; the edges may then be bound with paper. in using different colored solutions, collodion, etc., i have found that one will change the focus and the other not. with some screens you must focus with them in their positions; take away the screen, and the picture appears out of focus. i cannot fully explain why it is, and for this reason will not make the attempt; experience alone can teach it. another thing that has been tried lately is to do away with the yellow screen by substituting a yellow coating direct on the plate. no doubt the focus on an object that requires absolute sharpness is somewhat affected by the use of a glass. we have been successful, on a small scale, to coat the plate with the following yellow solution: place in a tray enough of a saturated solution of tropæolin in wood alcohol to cover the plate; allow it to remain ten seconds. it is necessary that the plate should be bathed previously in erythrosine and dried. before applying the tropæolin, which, being in alcohol, dries in a few minutes, have some blotting paper on hand, as the solution gathers in a pool and leaves bad marks on the end of the plate. the plate can be developed in the usual way. try it and see the results.--_reported in the beacon._ * * * * * platinotype printing.[ ] [footnote : a communication to the north london photographic society.] platinotype, which may be considered to be the most artistic of photographic printing processes, may be separated into its three modifications--the hot bath and cold bath, in which a faintly visible image is developed, and the pizzighelli printing-out paper. the hot bath process, again, may be divided into the black and white and sepia papers. i intend to give you a rough outline of the preparation of the paper and working of these modifications, concluding by demonstrating the hot bath method, and handing around prints by it. platinotype may almost be styled an iron printing process, for, while no trace of iron or its salts is found in the finished print, certain salts of iron are mixed with the platinum salt, which is platinum combined with two atoms of chlorine (ptcl ), as a means for readily reducing it; this, however, cannot be effected without the presence of neutral oxalate of potash, hence the use of the oxalate bath. there is no platinum in the paper for the cold bath process, it being coated with ferric oxalate mixed with a very small quantity of chloride of mercury--somewhere about one grain to an ounce of ferric oxalate solution. when dry it is ready for exposure, which is about three times less than with silver printing. it is absolutely necessary to store all papers for platinum printing in an air-tight tin containing chloride of calcium, which must be dried by heating from time to time. for the cold bath, however, it is important to have moisture present during printing, or it may be after printing and before development. if the paper is left in a dampish room for fifteen minutes, it should be sufficient. prints made by exposing damp paper, or damping dry paper just before development, must be developed within one hour if the maximum of vigor is desired; by delaying the development some hours, the prints in the meantime being stored in a drawer so that they may retain their moisture, an increase of half tone and warmth of color will be obtained. if it should be necessary to delay development for a day or two, the prints must be dried before a fire soon after being removed from the frames, and then stored in a calcium tube until wanted for development. while printing, the lemon color of the paper receives a grayish colored image, which, although faint, can, with practice, be judged as easily as silver printing. the developer consists of oxalate of potash and potassic chloro-platinite--about thirty grains of the platinum salt to half an ounce of oxalate forming about six ounces of solution; a great many variations, however, may be made in the proportions of platinum salt and oxalate, and different effects secured. development is effected by sliding the print face downward on to the developer, which must be rocked after the development of each print to avoid scum marks. to clear the prints they are washed in three or four baths of a weak solution of hydrochloric acid after leaving the developer, to remove all traces of the iron salts, and finally washed for a quarter of an hour in three changes of water; they are then finished, and may be dried between clean blotting paper. pizzighelli's process differs from the above in being one that prints fully out in the frame without development; the paper contains the platinum and iron salts as well as the developer, and so prints and develops at the same time. although excellent prints can be produced with it, for general work the results of the paper, as at present made, will not compare with the hot and cold bath processes. it is, however, excellent for printing from very dense negatives, and occasional negatives that seem extremely suitable for it. the paper should be breathed on before printing, as if it is quite dry the printing will be very slow and irregular. the best conditions for the preparation of the paper have scarcely been decided upon yet, and it is not quite fair to judge the process. the prints are cleared in the acid baths and washed for about a quarter of an hour. the sepia and black hot bath processes are much alike in the general treatment. there are, however, some special precautions to be observed with the sepia paper, the chief being to protect it from any but the faintest rays of light; the prints, unlike the black ones, may be affected by light when in the acid bath. a special solution must be added to the developer to keep the lights pure. over-exposure cannot be corrected by using a cooler bath, as is the case with the black prints, and the paper does not remain good so long. the paper for the black prints by the hot bath process is washed with a mixture of potassic platinous chloride and ferric oxalate, the proportion being about sixty grains of the platinum salt to one ounce of the iron solution. it will not keep good longer than twenty minutes or so, and must be applied to the paper directly after mixing. the ferric oxalate in the paper is reduced by the action of light to ferrous oxalate, which forms the faint visible image; this, when the paper is floated on the oxalate of potash bath, is capable of reducing the platinum salt in contact with it into metallic platinum; but the ferric salt, which remains unaltered, has no action on the platinum salt, leaving these parts, which represent the high lights of the print, untouched. the ferric oxalate is removed by the acid baths which follow the development. a good temperature for development is ° fahr., and when using this so much detail should not be apparent as when printing for the cold bath process, in which all the detail desired should be very faintly visible. there are, however, many methods of exposing the paper and developing it, and no fixed rule can be made, but the development must in every case be suited to the exposure or the result will be a failure. for instance, the paper may be printed until all detail is visible, but a very much cooler development must be used, say ° or °; on the other hand, a slightly short exposure may be given, and a temperature of ° to ° used. ° should be taken as the normal temperature, and kept to until some experience has been gained, as employing all temperatures will lead to confusion, and nothing will be learned. some negatives require a special treatment, and both printing and development must be altered, while for a very dense negative the paper may be left out in a dampish room for some time. it will then print with less contrast and more half tone. a thin negative is better printed by the cold bath process, but negatives should be good and brilliant for platinotype printing. any one taking up platinotype and getting only weak prints would do well to look to his negatives instead of blaming the paper, as the high lights should be fairly dense, and the deep shadows nearly clear glass. time for complete development should always be allowed; with a hot bath fifteen seconds will be sufficient, but if a cooler development is used, or the prints are solarized in the shadows, more time should be allowed. when the deep shadows are solarized, or appear lighter than surrounding parts, a hot and prolonged development is required to obtain sufficient blackness, as they have a tendency to look like brown paper. i have found breathing on solarized shadows useful, as in the presence of slight moisture they begin to print out and become dark before development, getting black almost directly the print is floated on the oxalate. three or four acid baths of about ten minutes each are used, and the prints are washed as before. the process throughout takes much less time than silver printing, and can be kept on all the winter, when it is nearly impossible to print in silver. prints can be developed in weak daylight or gaslight, and prolonged washing is dispensed with.--_n.p. fox, reported in br. jour. of photo._ * * * * * [continued from supplement, no. , page .] on allotropic forms of silver. by m. carey lea. in the first part of this paper were described certain forms of silver; among them a lilac blue substance, very soluble in water, with a deep red color. after undergoing purification, it was shown to be nearly pure silver. during the purification by washing it seemed to change somewhat, and, consequently, some uncertainty existed as to whether or not the purified substance was essentially the same as the first product; it seemed possible that the extreme solubility of the product in its first condition might be due to a combination in some way with citric acid, the acid separating during the washing. many attempts were made to get a decisive indication, and two series of analyses, one a long one, to determine the ratio between the silver and the citric acid present, without obtaining a wholly satisfactory result, inasmuch as even these determinations of mere ratio involved a certain degree of previous purification which might have caused a separation. this question has since been settled in an extremely simple way, and the fact established that the soluble blue substance contains not a trace of combined citric acid. the precipitated lilac blue substance (obtained by reducing silver citrate by ferrous citrate) was thrown on a filter and cleared of mother water as far as possible with a filter pump. pure water was then poured on in successive portions until more than half the substance was dissolved. the residue, evidently quite unchanged, was, of course, tolerably free from mother water. it was found that by evaporating it to dryness over a water bath, most of the silver separated out as bright white normal silver; by adding water and evaporating a second time, the separation was complete, and water added dissolved no silver. _the solution thus obtained was neutral._ it must have been acid had any citric acid been combined originally with the silver. this experiment, repeated with every precaution, seems conclusive. the ferrous solution, used for reducing the silver citrate, had been brought to exact neutrality with sodium hydroxide. after the reduction had been effected, the mother water over the lilac blue precipitate was neutral or faintly acid. a corroborating indication is the following: the portions of the lilac blue substance which were dissolved on the filter (see above) were received into a dilute solution of magnesium sulphate, which throws down insoluble allotropic silver of the form i have called b (see previous paper). this form has already been shown to be nearly pure silver. the magnesia solution, neutral before use, was also neutral after it had effected the precipitation, indicating that no citric acid had been set free in the precipitation of the silver. it seems, therefore, clear that the lilac blue substance contains no combined citric acid. had the solubility of the silver been due to combination with either acid or alkali, the liquid from which it was separated by digestion at or below ° c. must have been acid or alkaline; it could not have been neutral. we have, therefore, this alternative: in the lilac blue substance we have either pure silver in a soluble form or else a compound of silver, with a perfectly neutral substance generated from citric acid in the reaction which leads to the formation of the lilac blue substance. if this last should prove the true explanation, then we have to do with a combination of silver of a quite different nature from any silver compounds hitherto known. a neutral substance generated from citric acid must have one or more atoms of hydrogen replaced by silver. this possibility recalls the recent observations of ballo, who, by acting with a ferrous salt on tartaric acid, obtained a neutral colloid substance having the constitution of arabin, c h o . to appreciate the difficulty of arriving at a correct conclusion, it must be remembered that the silver precipitate is obtained saturated with strong solutions of ferric and ferrous citrate, sodium citrate, sulphate, etc. these cannot be removed by washing with pure water, in which the substance itself is very soluble, but must be got rid of by washing with saline solutions, under the influence of which the substance itself slowly but continually changes. next, the saline solution used for washing must be removed by alcohol. during this treatment, the substance, at first very soluble, gradually loses its solubility, and, when ready for analysis, has become wholly insoluble. it is impossible at present to say whether it may not have undergone other change; this is a matter as to which i hope to speak more positively later. it is to be remarked, however, that these allotropic forms of silver acquire and lose solubility from very slight causes, as an instance of which may be mentioned the ease with which the insoluble form b recovers its solubility under the influence of sodium sulphate and borate, and other salts, as described in the previous part of this paper. the two insoluble forms of allotropic silver which i have described as b and c--b, bluish green; c, rich golden color--show the following curious reaction. a film of b, spread on glass and heated in a water stove to ° c. for a few minutes becomes superficially bright yellow. a similar film of the gold colored substance, c, treated in the same way, acquires a blue bloom. in both cases it is the surface only that changes. _sensitiveness to light._--all these forms of silver are acted upon by light. a and b acquire a brownish tinge by some hours' exposure to sunlight. with c the case is quite different, the color changes from that of red gold to that of pure yellow gold. the experiment is an interesting one. the exposed portion retains its full metallic brilliancy, giving an additional proof that the color depends upon molecular arrangement, and this with the allotropic forms of silver is subject to change from almost any influence. _stability._--these substances vary greatly in stability under influences difficult to appreciate. i have two specimens of the gold yellow substance, c, both made in december, , with the same proportions, under the same conditions. one has passed to dazzling white, normal silver, without falling to powder, or undergoing disaggregation of any sort; the fragments have retained their shape, simply changing to a pure frosted white, remaining apparently as solid as before; the other is unchanged, and still shows its deep yellow color and golden luster. another specimen made within a few months and supposed to be permanent has changed to brown. complete exclusion of air and light is certainly favorable to permanence. _physical condition._--the brittleness of the substances b and c, the facility with which they can be reduced to the finest powder, makes a striking point of difference between allotropic and normal silver. it is probable that normal silver, precipitated in fine powder and set aside moist to dry gradually, may cohere into brittle lumps, but these would be mere aggregations of discontinuous material. with allotropic silver the case is very different, the particles dry in optical contact with each other, the surfaces are brilliant, and the material evidently continuous. that this should be brittle indicates a totally different state of molecular constitution from that of normal silver. _specific gravities._--the allotropic forms of silver show a lower specific gravity than that of normal silver. in determining the specific gravities it was found essential to keep the sp. gr. bottle after placing the material in it for some hours under the bell of an air pump. films of air attach themselves obstinately to the surfaces, and escape but slowly even in vacuo. taken with this precaution, the blue substance, b, gave specific gravity . , and the yellow substance, c, specific gravity . . the specific gravity of normal silver, after melting, was found by g. rose to be . . that of finely divided silver obtained by precipitation is stated to be . .[ ] [footnote : watts' dict., orig. ed., v. .] i believe these determinations to be exact for the specimens employed. but the condition of aggregation may not improbably vary somewhat in different specimens. it seems, however, clear that these forms of silver have a lower specific gravity than the normal, and this is what would be expected. chestnut hill, philadelphia, may, . --_amer. jour. of science._ * * * * * turpentine and its products.[ ] [footnote : read at a meeting of the liverpool chemists' association.] by edward davies, f.c.s., f.i.c. in treating this subject it is necessary to limit it within comparatively narrow bounds, for bodies of the turpentine class are exceedingly numerous and not well understood. in this definite class turpentine means the exudation from various trees of the natural order coniferæ, consisting of a hydrocarbon, c h , and a resin. the constitution of the hydrocarbons in turpentine from different sources, though identical chemically, varies physically, the boiling point ranging from ° c. to ° c., the density from . to . , and the action on polarized light from - . to + . . they are very unstable bodies in their molecular constitution, heat, sulphuric acid, and other reagents modifying their properties. the resins are also very variable bodies formed probably by oxidation of the hydrocarbons, and as this oxidation is more or less complete, mixtures are formed very difficult to separate and study. turpentine as met with in commerce is mainly derived from _pinus maritima_, yielding french turpentine, and _pinus australis_, furnishing most of the american turpentine. the latter is obtained from north and south carolina, georgia and alabama. in hanbury and fluckiger's pharmacographia there is a full description of the manner in which the trees are wounded to obtain the turpentine. besides these there are venice turpentine from the larch, _pinus larix_, strassburg turpentine from _abies pectinata_, and canada balsam from _pinus balsamea_. the crude american turpentine is a viscid liquid of about the consistence of honey, but varying to a soft solid, known as gum, thus, according to the amount of exposure which it has undergone, it contains about to per cent. of "spirits," to which the name of turpentine is commonly given, the rest being resin, or as it is usually called, rosin. in liverpool almost all the spirits of turpentine comes from america, so that it is almost impossible to get a sample of french. the terpene from american turpentine is called austraterebenthene. it possesses dextro-rotatory polarization of + . . its density is . . boiling point ° c. in taking the boiling point of a commercial sample of spirits it is necessary to wait until the thermometer becomes steady. not more than per cent. should pass over before this takes place, and then there is not more than two or three degrees of rise until almost all is distilled over. the liquids of lower boiling point do not appear to have been much studied. in french spirits they seem to be of the same composition as the main product, but with more action on polarized light. french spirits of turpentine is mainly composed of terebenthene. the boiling point and sp. gr. are the same as those of the austraterebenthene, but the polarization is left handed and amounts to - . . isomeric modifications. heated to ° c. in a sealed tube for two hours, it becomes an isomeric compound, boiling at ° c., while the density is lowered, being only . at ° c. the rotatory power is only - °. it oxidizes much more rapidly. it is called isoterebenthene and has a smell of essential oil of lemons. by the action of a small quantity of sulphuric acid, among other products terebene is formed. it has the same boiling point and sp. gr. as terebenthene, but is without action on polarized light. austraterebenthene forms similar if not identical bodies. polymers. one part of boron fluoride bf instantly converts parts of terebenthene into polymers boiling above ° c., and optically inactive. h so does the same on heating and forms diterebene c h . terchloride of antimony does the same, and also produces tetraterebene c h , a solid brittle compound formed by the union of four molecules of c h . it does not boil below ° c. and decomposes on heating. compound with h o. terpin c h ho is formed when volume of spirits of turpentine is mixed with of nitric acid and of alcohol, and exposed to air for some weeks. crystals are formed which are pressed, decolorized by animal charcoal, and recrystallized from boiling water. compounds with hcl. when a slow current of hcl is passed through cooled spirits of turpentine, two isomeric compounds are formed, one solid, and one liquid. the lower the temperature is kept, the more of the solid body is produced. to obtain the solid body pure it is pressed and recrystallized from ether or alcohol. it is volatile and has the odor of camphor. it is called artificial camphor, and has the composition c h hcl. there is also a compound with hcl. oxidation products. by passing air into spirits of turpentine oxygen is absorbed. it was thought at one time that ozone was produced, but kingzett's view is that camphoric peroxide is formed c h o , and that in presence of water it decomposes into camphoric acid and h o . this liquid constitutes the disinfectant known as "sanitas," which possesses the advantages of a pleasant smell and non-poisonous properties. c h o may be obtained by exposing spirits of turpentine in a flask full of oxygen with a little water. camphor c h o has been made in small quantity by oxidizing spirits of turpentine. terebenthene belongs to the benzene or aromatic series, which can be shown from its connection with cymene. cymene is methylpropyl-benzene, and can be made from terpenes by removing two atoms of h. it has not yet been converted again into terpene, but the connection is sufficiently proved. the presence of ch in terpenes is shown by their yielding chloroform when distilled with bleaching powder and water. the resin is imperfectly known. it was supposed to consist of picric and sylvic acids. it is also stated to contain abietic anhydride c h o , but it is difficult to understand how a compound containing c can be produced from c h . the most probable view is that it is the anhydride of sylvic acid, which is probably c h o . the dark colored resin which is obtained when the turpentine is distilled without water can be converted into a transparent slightly yellow body by distillation with superheated steam. a small portion is decomposed, but the greater part distills unchanged. it is used in making soap which will lather with sea water. when distilled alone, various hydrocarbons, resin oil and resin pitch, are obtained. i find that commercial spirits of turpentine varies in sp. gr. from . to . at ° c. the higher sp. gr. appears to be connected with the presence of resinous bodies, the result of oxidation. the boiling point is very uniform, ranging from ° c. to ° c. at mm. taking these two points together, it is hardly possible to adulterate spirits of turpentine without detection. i give the figures for a few imitations or adulterations: sp. gr. b.p. no. . ° c. no. . ° c. no. . ° c. no. . ° c. there is a considerable difference in the flashing point, no doubt due to the longer or shorter exposure of the crude turpentine, by which more or less of the volatile portion escapes. * * * * * on the occurrence of paraffine in crude petroleum.[ ] [footnote : an abstract of thesis by e.a. partridge, class of ' , univ. of pa. read before the chemical section of the franklin institute by prof. s.p. sadtler.] it is well known that the paraffine obtained by the distillation of petroleum residues is crystalline, while that obtained directly (as in the filtration of residuum) is amorphous. ozokerite or ceresine differs but slightly from paraffine, the principal distinction being want of crystalline structure in it as found. other characteristics, such as the melting point, specific gravity, etc., vary in both, and so are not of importance in a comparison. hence it has been asked, is the paraffine occurring in petroleum and ozokerite identical with that which is produced by their distillation? as crystalline paraffine could be obtained from ozokerite by distillation alone, many persons have supposed that it was engendered in the process. recently, however, crystalline paraffine has been obtained from ozokerite by dissolving the latter in warm amyl alcohol; on cooling the greater part separates out in crystals having the luster of mother-of-pearl. by repetition of this process, a substance is obtained that is scarcely to be distinguished from the paraffine obtained by distillation. apparently there exists then in ozokerite, together with paraffine, other substances not capable of crystallization which keep the paraffine from crystallizing. these colloids appear to be separated by amyl alcohol in virtue of their greater solubility in that menstruum. it is also reasonable to suppose that they undergo change or decomposition by distillation. so as petroleum residues are amorphous, and the crystalline paraffine is first produced by distillation, it has been argued that the paraffine present in crude petroleum is approximately the same thing as ozokerite. this, however, is not sufficient to establish the pyrogenic origin of all crystallized paraffine, as crystals can be obtained from the amorphous residues by distillation at normal or reduced pressure or in a current of steam. to explain these facts two assumptions are possible. either the chemical and physical properties of all or some of the solid constituents are changed by the distillation, and the paraffine is changed from the amorphous into the crystalline variety, or the change produced by the distillation takes place in the medium (i.e., the mother liquid) in which the paraffine exists. the change effected in ozokerite and in petroleum residues when crystalline paraffine is obtained by distillation is to be regarded as a purification, and can be effected partially by treatment with amyl alcohol. in the same way, by repeated treatment of petroleum residuum with amyl alcohol, a substance of melting point ° c. can be obtained, which cannot be distinguished from ordinary paraffine. the treatment with amyl alcohol has therefore accomplished the same results as was obtained by distillation, and the action is probably the same, i.e., a partial separation of colloid substance. these facts point to the conclusion that crystallizable paraffine exists ready formed in both petroleum and in ozokerite, but in both cases other colloidal substances prevent its crystallization. by distillation, these colloids appear to be destroyed or changed so as to allow the paraffine to crystallize. it is a generally known fact that liquids always appear among the products of the distillation of paraffine, no matter in what way the distillation be conducted. this shows that some paraffine is decomposed in the operation. the name _proto-paraffine_ has been given to ozokerite and to the paraffine of petroleum in contradistinction to _pyro-paraffine_, the name that has been applied to the paraffine obtained by distillation from any source. according to reichenbach, paraffine may crystallize in three forms: needles, angular grains, and leaflets having the luster of mother-of-pearl. hofstadter, in an article on the identity of paraffine from different sources, confirmed this statement, and added further that at first needles, then the angular forms, and then the leaflets are formed. fritsche found, by means of the microscope, in the ethereal solution of ozokerite, very fine and thin crystal leaflets concentrically grouped, and in the alcoholic solution fine irregular leaflets. zaloziecki has recently developed these microscopic investigations to a much greater extent. according to this observer, the principal part of paraffine, as seen under the microscope, consists of shining stratified leaflets with a darker edge. the most characteristic and well developed crystals are formed by dissolving paraffine in a mixture of ethyl and amyl alcohols and chilling. the crystals are rhombic or hexagonal tablets or leaves, and are quite regularly formed. they are unequally developed in different varieties of paraffine. the best developed are those obtained from ceresine. their relative size and appearance give an indication as to the purity of the paraffine, and, as they are always present, they are to be counted among the characteristic tests for paraffine. reichenbach observed that mere traces of empyreumatic oil prevented their formation. the old method of determining the amount of paraffine in petroleum was to carry out the refining process on a small scale; that is, to distill the residue from the kerosene oils to coking, chill out the paraffine, press it thoroughly between filter paper, and weigh the residue. the sources of error in this procedure are manifold; the principal one is the solubility of paraffine in oils, which depends upon the character of both the paraffine and the oil, and also upon the temperature. the next greatest source of error is variation in the process of distillation and the difference between working on the small scale and on the large scale. in most cases, where a paraffine determination is to be carried out, one has to deal with a mixture of paraffine with liquid oils. now, paraffine is not a substance defined by characteristic physical properties which distinguish it from the liquid portions of petroleum. it consists of a mixture of homologous hydrocarbons, which form a solid under ordinary conditions. the hydrocarbons of this mixture show a gradation in their properties, and gradually approximate to those which are liquid at ordinary temperatures. it is a well known fact that a separation of these homologues is entirely impossible by distillation. it has also been ascertained that the liquid constituents of petroleum do not always possess boiling points that are lower than those of the solid constituents. this shows that we have to deal not merely with hydrocarbons of one, but of several series. when determinations of the amount of paraffine are to be made, then it becomes necessary to specify with exactness what is to be called paraffine. the most definite property that can be made use of for this purpose is the melting point. for several reasons it is convenient to include under this name hydrocarbons of melting point as low as °- ° c. the method proposed by zaloziecki for the determination of paraffine is the following: the most volatile portions of the petroleum are separated by distillation, until the thermometer shows ° c. these portions are separated, as they exert great solvent action upon paraffine. at the same time he finds that no pyro-paraffine is formed under this temperature. a weighed portion of the residue is taken and mixed with ten parts by weight of amyl alcohol and ten parts of seventy-five per cent. ethyl alcohol: the mixture is then chilled for twelve hours to ° c. it is then filtered cold, washed first with a mixture of amyl and ethyl alcohols, and then with ethyl alcohol alone. the paraffine is transferred to a small porcelain evaporating dish and dried at ° c. it is then heated with concentrated sulphuric acid to °- ° c. for fifteen to thirty minutes with constant stirring. the acid is then neutralized and the paraffine extracted by petroleum ether. on evaporation of the solvent, the paraffine is dried at ° c. and weighed. zaloziecki found, according to this method, in three samples of galician petroleums, . , . and . per cent., respectively, of proto-paraffine. the method was carried out as above with four samples of american petroleums, colorado oil from florence, col.; warren county oil from wing well, warren, pa.; washington oil from washington county, pa.; middle district oil from butler county, pa., all furnished by professor sadtler. they were very different in physical properties and in appearance, the colorado oil being a much heavier oil than the others and the washington oil being an amber oil, while the other two were of the ordinary dark green color and consistence. the losses on distillation to ° c. were very different, being about one-tenth in the case of the colorado oil and nearly one-half in the case of the others. the percentages of partially refined proto-paraffine in the four reduced oils (all below ° c. off) were as follows: for the colorado oil, . per cent.; for the warren oil, . per cent.; for the washington oil, . per cent.; and for the middle district oil, . per cent. the question now arises, what value has this determination of the proto-paraffine which may exist in an oil? as before said, a portion of the paraffine is always decomposed in distillation at temperatures sufficiently high to drive over the paraffine oils, so the yield of pyro-paraffine is always less than the proto-paraffine shown to be present originally. zaloziecki found this in the case of the several galician oils he examined. corresponding to the . , . and . per cent. of proto-paraffine in the several oils he obtained . , . and . per cent., respectively, of pyro-paraffine. for the present, however, the extraction of proto-paraffine on a large scale by means of such solvents as amyl and ethyl alcohols is out of the question on account of their cost. a distillation, under reduced pressure and with superheated steam, would, however, prevent much of the decomposition of the original proto-paraffine and increase the yield of pyro-paraffine. this study of zaloziecki's method and the examination of american oils was suggested by professor sadtler and carried out in his laboratory. * * * * * transmission of pressure in fluids. by albert b. porter. the young student of physics occasionally has difficulty in grasping the laws of pressure in fluids. his every day experience has taught him that a push against a solid body causes it to push in the same direction, and he often receives with some doubt the statement that pressure applied to a fluid is transmitted equally in every direction. the experiments ordinarily shown in illustration of this principle prove that pressure is transmitted in all directions, but do not prove the equality of transmission, and in spite of all the text books may tell him, the student is apt to cling to the idea that a downward pressure applied to a liquid is more apt to burst the bottom than the side of the containing vessel. [illustration: figs. . and .] the little piece of apparatus shown in fig. was designed to furnish a clear demonstration of the principle under consideration. it is essentially an arrangement by which a downward pressure is applied to a confined mass of air or water, and the resultant pressures measured in the three directions, down, up, and sideways. by means of a broken rat tail file kept wet with turpentine three holes are bored through a bottle, one through the bottom, one through the side, and one through the shoulder, as near the neck as may be convenient. the operation is quick and easy, the only precaution to be observed being to work very slowly and use but a slight pressure when the glass is nearly perforated. the holes may be enlarged to any size required by careful filing with the wet file. from each of the holes a rubber tube leads to one of the glass manometer tubes at the right in the figure, the joints being made air tight by slipping into each rubber tube a piece of glass tubing about half an inch long in order to swell it to the size of the hole it is to fit. the ends of these glass tubes must be well rounded by partial fusion in a gas flame, that there may be no sharp edges to cut the rubber. the bottle rests in a depression in the turned wood base, the lower rubber tube passing out through a hole in the wood. fig. shows the shape of the manometer tubes. they are made of quarter inch glass tubing bent to shape in a flame and left open at both ends. they are mounted on a scale board which has several equidistant horizontal lines running across it. the two bent wires which support the scale board fit loosely in holes in it and in the base. this method of mounting is very handy, since it permits the scale board to be swung to right or left as may be convenient, or turned round so as to show the fittings on its back, without moving the bottle. the three manometers are filled to the same level with mercury, the quantity being adjusted by means of a pipette. a perforated rubber stopper, fitted with a glass tube on which is slipped a rubber syringe bulb, completes the apparatus. when the bulb is pinched between the fingers, the mercury is forced up to the same height in each of the manometers, thus proving that the pressure is exerted equally in the three directions, up, down, and sideways. with the bottle filled with water the same effect follows, the law being the same for liquids and gases. when using water in the apparatus it is essential that the rubber tubes, as well as the bottle, be filled, and when used in the class room it is better to show the experiment with water first, it being easier and quicker to empty the bottle and tubes than to fill them. * * * * * pear duchesse d'angouleme. although well known to fruit growers and generally represented in all parts of britain, this noble french pear has not become a universal favorite. if the quality of the fruit, independently of its fine, handsome appearance, was bad, or even indifferent, it might be exterminated from our lists, but this we know is not the case, as any one who has tasted good samples grown in france, the channel islands, and upon favorable soils in this country will bear out the statement that the flavor is superb. some fruits, we know, are quite incapable of being good, as they have no quality in them; but here we have one of the hardiest of trees, capable of giving us quantity as well as quality, provided we cultivate properly. pears, no doubt, are capricious, like our seasons, but given a good average year, soils and stocks which suit them, a light, warm, airy aspect, and good culture, a great number of varieties formerly only good enough for stewing are now elevated, and most deservedly so, to the dessert table. but, assuming that some sorts known to be good do not reach their highest standard of excellence every year, they are infinitely superior to many of the old stewers, as they carry their own sugar, a quality which fits them for consumption by the most delicate invalids. indeed, so prominently have choice dessert pears, and apples too for that matter, come to the front for cooking purposes, that a new demand is now established, and although duchesse d'angoulême, always juicy and sweet, from bad situations does not always come up to the fine quality met within covent garden in november, it is worthy of our skill, as we know it has all the good points of a first rate pear when properly ripened. the original tree of this pear was observed by m. anne pierre andusson, a nurseryman at angers, growing in a farm garden near champigne, in anjou, and having procured grafts of it, he sold the trees, in , under the name of poire des eparannais. in , he sent a basket of the fruit to the duchesse d'angoulême, with a request to be permitted to name the pear in honor of her. the request was granted, and the pear has since borne its present name. that such a fine pear, which does so well in france, would soon find its way to england there exists little doubt, as we find that within a few years it became established and well known throughout the united kingdom. all the earliest trees would be worked upon the pear or free stock, and as root pruning until recently was but little practiced, we may reasonably suppose that the majority of them are deeply anchored in clay, marl, and other subsoils calculated to force a crude, gross growth from which high flavored fruit could not be expected. these defects under modern culture upon the quince and double grafting are giving way, as we find, on reference to the report of the committee of the pear conference, held at chiswick in , that twenty counties in england, also scotland, ireland, and wales, contributed no less than dishes to the tables, and thirty-eight growers voted in favor of the duchesse being recognized as one of our standard dessert varieties. this step looks like progress, as it is a record of facts which cannot be gainsaid, and it now remains to be seen whether the english grower, whose indomitable will has brought him to the front in the subjugation of other fruits, will be successful with the fine duchesse d'angoulême. although this remarkable pear cannot easily be mistaken, for the benefit of those who do not know it, the following description may not be out of place. fruit large, often very large, ½ inches wide and inches to inches high, roundish obovate, uneven, and bossed in its outline. skin greenish yellow, changing to pale dull yellow, covered with veins and freckles of pale brown russet, and when grown against a south wall it acquires a brown cheek. eye open, with erect dry segments, set in a deep irregular basin. stalk inch long, inserted in a deep irregular cavity. flesh white, buttery, and melting, with a rich flavor when well ripened; otherwise rather coarse grained and gritty. as to culture, experienced fruitists say the tree grows vigorously and well. it bears abundantly, and succeeds either on the pear or quince stock, forming handsome pyramids, but is better on the quince. here, then, we have the key to the secret of success: the cordon on the quince; roots near the surface; loam, sound, sandy, and good; and good feeding. aspect, a good wall facing south or west--the latter, perhaps, the best. those who have not already done so, should try trees on the quince as pyramids and bushes, as this, like some other capricious pears, although the fruit be smaller, may put in better flavor than is met with in fruit from hot walls.--_the garden._ * * * * * succession of forest growths. the following is from an address delivered by mr. robert douglas before the association of american nurserymen at the meeting in chicago recently. it is the prevailing and almost universal belief that when native forests are destroyed they will be replaced by other kinds, for the simple reason that the soil has been impoverished of the constituents required for the growth of that particular tree or trees. this i believe to be one of the fallacies handed down from past ages, taken for granted, and never questioned. nowhere does the english oak grow better than where it grew when william the conqueror found it at the time he invaded britain. where do you find white pines growing better than in parts of new england where this tree has grown from time immemorial? where can you find young redwoods growing more thriftily than among their giant ancestors, nearly or quite as old as the christian era? the question why the original growth is not reproduced can best be answered by some illustrations. when a pine forest is burned over, both trees and seeds are destroyed, and as the burned trees cannot sprout from the stump like oaks and many other trees, the land is left in a condition well suited for the germination of tree seeds, but there are no seeds to germinate. it is an open field for pioneers to enter, and the seeds which arrive there first have the right of possession. the aspen poplar (_populus tremuloides_) has the advantage over all other trees. it is a native of all our northern forests, from the atlantic to the pacific. even fires cannot eradicate it, as it grows in moist as well as dry places, and sprouts from any part of the root. it is a short-lived tree, consequently it seeds when quite young and seeds abundantly; the seeds are light, almost infinitesimal, and are carried on wings of down. its seeds ripen in spring, and are carried to great distances at the very time when the ground is in the best condition for them. even on the dry mountain sides in colorado, the snows are just melting and the ground is moist where they fall. to grow this tree from seed would require the greatest skill of the nurseryman, but the burnt land is its paradise. wherever you see it on high, dry land you may rest assured that a fire has been there. on land slides you will not find its seeds germinating, although they have been deposited there as abundantly as on the burned land. next to the aspen and poplars comes the canoe birch, and further north the yellow birch, and such other trees as have provision for scattering their seeds. i have seen acorns and nuts germinating in clusters on burned lands in a few instances. they had evidently been buried there by animals and had escaped the fires. i have seen the red cherry (_prunus pennsylvanica_) coming up in great quantities where they might never have germinated had not the fires destroyed the debris which covered the seed too deeply. a careful examination around the margin of a burned forest will show the trees of surrounding kinds working in again. thus by the time the short-lived aspens (and they are very short-lived on high land) have made a covering on the burned land, the surrounding kinds will be found re-established in the new forest, the seeds of the conifers, carried in by the winds, the berries by the birds, the nuts and acorns by the squirrels, the mixture varying more or less from the kinds which grew there before the fire. it is wonderful how far the seeds of berries are carried by birds. the waxwings and cedar birds carry seeds of our tartarean honeysuckles, purple barberries and many other kinds four miles distant, where we see them spring up on the lake shore, where these birds fly in flocks to feed on the juniper berries. it seems to be the same everywhere. i found european mountain ash trees last summer in a forest in new hampshire; the seed must have been carried over two miles as the crow flies. while this alternation is going on in the east, and may have been going on for thousands of years, the rocky mountain district is not so fortunate. when a forest is burned down in that dry region, it is doubtful if coniferous trees will ever grow again, except in some localities specially favored. i have seen localities where short-lived trees were dying out and no others taking their places. such spots will hereafter take their places above the timber line, which seems to me to be a line governed by circumstances more than by altitude or quality of soil. there are a few exceptions where pines will succeed pines in a burned-down forest. _pinus murrayana_ grows up near the timber line in the rocky mountains. this tree has persistent cones which adhere to the trees for many years. i have counted the cones of sixteen years on one of these trees, and examined burned forests of this species, where many of the cones had apparently been bedded in the earth as the trees fell. the heat had opened the cones and the seedlings were growing up in myriads; but not a conifer of any other kind could be seen as far as the fire had reached. in the michigan peninsula, northern wisconsin and minnesota, _p. banksiana_, a comparatively worthless tree, is replacing the valuable red pine (_p. resinosa_), and in the sierras _p. murrayana_ and _p. tuberculata_ are replacing the more valuable species by the same process. in this case, also, the worthless trees are the shortest lived. so we see that nature is doing all that she can to remedy the evil. man only is reckless, and especially the american man. the mexican will cut large limbs off his trees for fuel, but will spare the tree. even the poor indian, when at the starvation point, stripping the bark from the yellow pine (_p. ponderosa_), for the mucilaginous matter being formed into sap wood, will never take a strip wider than one third the circumference of the tree, so that its growth may not be injured. we often read that oaks are springing up in destroyed forests where oaks had never grown before. the writers are no doubt sincere, but they are careless. the only pine forests where oaks are not intermixed are either in land so sandy that oaks cannot be made to grow on them at all, or so far north that they are beyond their northern limit. in the green mountains and in the new england forests, in the pine forests in pennsylvania, in the adirondacks, in wisconsin and michigan--except in sand--i have found oaks mixed with the pines and spruces. in northwestern minnesota and in northern dakota the oaks are near their northern limit, but even there the burr oak drags on a bare existence among the pines and spruces. in the black hills, in dakota, poor, forlorn, scrubby burr oaks are scattered through the hills among the yellow pines. in colorado we find them as shrubs among the pines and douglas spruces. in new mexico we find them scattered among the piñons. in arizona they grow like hazel bushes among the yellow pines. on the sierra nevada the oak region crosses the pine region, and scattering oaks reach far up into the mountains. yet oaks will not flourish between the one hundredth meridian and the eastern base of the sierras, owing to the aridity of the climate. i recently found oaks scattered among the redwoods on both sides of the coast range mountains. darwin has truly said, "the oaks are driving the pines to the sands." wherever the oak is established--and we have seen that it is already established whereever it can endure the soil and climate--there it will remain and keep on advancing. the oak produces comparatively few seeds. where it produces a hundred, the ash and maple will yield a thousand, the elm ten thousand, and many other trees a hundred thousand. the acorn has no provision for protection and transportation like many tree seeds. many kinds are furnished with wings to float them on the water and carry them in the air. nearly every tree seed, except the acorn, has a case to protect it while growing, either opening and casting the seeds off to a distance when ripe or falling with them to protect them till they begin to germinate. even the equally large seeds of other kinds are protected in some way. the hickory nut has a hard shell, which shell itself is protected by a strong covering until ripe. the black walnut has both a hard shell and a fleshy covering. the acorn is the only seed i can think of which is left by nature to take care of itself. it matures without protection, falls heavily and helplessly to the ground, to be eaten and trodden on by animals, yet the few which escape and those which are trodden under are well able to compete in the race for life. while the elm and maple seeds are drying up on the surface, the hickories and the walnuts waiting to be cracked, the acorn is at work with its coat off. it drives its tap root into the earth in spite of grass, and brush, and litter. no matter if it is shaded by forest trees so that the sun cannot penetrate, it will manage to make a short stem and a few leaves the first season, enough to keep life in the root, which will drill in deeper and deeper. when age or accident removes the tree which has overshadowed it, then it will assert itself. fires may run over the land, destroying almost everything else, the oak will be killed to the ground, but it will throw up a new shoot the next spring, the root will keep enlarging, and when the opportunity arrives it will make a vigorous growth, in proportion to the strength of the root, and throw out strong side roots, and after that care no more for its tap root, which has been its only support, than the frog cares for the tail of the tadpole after it has got on its own legs. there is no mystery about the succession of forest growths, nothing in nature is more plain and simple. we cannot but admire her wisdom, economy, and justness, compensating in another direction for any disadvantage a species may have to labor under. every kind of tree has an interesting history in itself. seeds with a hard shell, or with a pulpy or resinous covering which retards their germination, are often saved from becoming extinct by these means. the red cedar (_juniperus virginiana_) reaches from florida to and beyond cape cod; it is among the hills of tennessee, through the middle states and new england. it is scattered through the western states and territories, at long distances apart, creeping up the platte river, in nebraska. (i found only three in the black hills, in dakota, in an extended search for the different trees which grow there. found only one in a long ramble in the hills at las vegas, new mexico.) yet this tree has crept across the continent, and is found here and there in a northwesterly direction between the platte and the pacific coast. it is owing to the resinous coating which protects its seeds that this tree is found to-day scattered over that immense region. * * * * * [nature.] the "hatchery" of the sun-fish. i have thought that an example of the intelligence (instinct?) of a class of fish which has come under my observation during my excursions into the adirondack region of new york state might possibly be of interest to your readers, especially as i am not aware that any one except myself has noticed it, or, at least, has given it publicity. the female sun-fish (called, i believe, in england, the roach or bream) makes a "hatchery" for her eggs in this wise. selecting a spot near the banks of the numerous lakes in which this region abounds, and where the water is about inches deep, and still, she builds, with her tail and snout, a circular embankment inches in height and thick. the circle, which is as perfect a one as could be formed with mathematical instruments, is usually a foot and a half in diameter; and at one side of this circular wall an opening is left by the fish of just sufficient width to admit her body, thus: [illustration] the mother sun-fish, having now built or provided her "hatchery," deposits her spawn within the circular inclosure, and mounts guard at the entrance until the fry are hatched out and are sufficiently large to take charge of themselves. as the embankment, moreover, is built up to the surface of the water, no enemy can very easily obtain an entrance within the inclosure from the top; while there being only one entrance, the fish is able, with comparative ease, to keep out all intruders. i have, as i say, noticed this beautiful instinct of the sun-fish for the perpetuity of her species more particularly in the lakes of this region; but doubtless the same habit is common to these fish in other waters. william l. stone. jersey city heights, n.j. * * * * * ancient lake dwellings. among the many traces which man has left of his existence in long past ages on the face of the earth, says a correspondent of the _scotsman_, none are more interesting and instructive than the lake dwellings of switzerland and other countries, which have been discovered within the last fifty years or so. although these relics of the past are far more modern than those which we referred to in a late article on "primeval man," and are probably included within the range of egyptian and other chronologies, yet they stretch far beyond the historic period, so far as europe is concerned, and throw a flood of light on the habits of our ancestors, or at any rate predecessors, in these regions. we are tolerably well acquainted with the history of the jews when david worked his way up from the shepherd's staff to the royal scepter, or when joshua drove out the canaanites and took possession of their land, but of what was going on in europe in these times we have hitherto had no knowledge whatever. these lake dwellings, however, were in all probability inhabited by human beings somewhere about the time when the events we have referred to took place, and may have been inhabited before the earlier of them. the first hint we had of the existence of these remarkable dwellings was obtained in , when an excavation was being made on the shore of a swiss lake. some wooden piles, apparently very old, and other antiquities were found by the workmen. not much attention, however, was paid to this discovery till , when a mr. aeppli drew attention to some remains of human handiwork found near his house, in part of the bed of a lake which had been left dry during a season of great drought. the workmen employed in recovering some land from the lake found the heads of a great many wooden piles protruding through the mud, and also a number of stags' horns, and implements of various descriptions. stimulated by this discovery, search was made in various lakes, and the result was truly astonishing. in every direction remains of the habitations of prehistoric man were discovered, and relics were found in such abundance that the history of this unknown past could be traced through long ages, and the habits of the people ascertained with a very considerable amount of probability. the details are so numerous that it would be impossible in the space at our disposal to go into them all. of course, during the long time that has elapsed since these structures were erected, their remains have been reduced to mere ruins, and it is only by comparing one with another that we are able to picture to ourselves what they were originally like and what sort of life was led by the men who inhabited them. the oldest of these dwellings belong to the stone age, when man had not acquired any knowledge of the use of metal; when all his instruments were merely sharpened stones, fixed in wooden handles, or pieces of bone, horn, or other natural material. they are therefore somewhat roughly finished, but at the same time exhibit considerable ingenuity and skill. the method of construction seems to have been somewhat as follows: a suitable situation, not far from the shore, where the water was not very deep, having been fixed upon, these prehistoric builders drove into the muddy bottom of the lake a number of piles or long stakes, arranged generally pretty close together, and in some sort of regular order. these piles were formed generally from stems of trees, with the bark on, but occasionally from split wood. the ends were sharpened to a point by the aid of fire or by cutting with stone axes. on a sufficient number being driven in, and their upper ends brought to a level above the surface of the water, platform beams were laid across, fastened by wooden pegs, or in some cases fixed into notches cut in the heads of the vertical piles. the platform was generally very roughly made, just a series of unbarked stems placed side by side and covered with layers of earth or clay, with numerous openings through which refuse of all kinds fell into the water beneath. in many cases connection with the shore was made by means of a narrow bridge or gangway, constructed in the same manner. on this rude platform huts were erected by driving small piles or stakes which projected above the floor, and to these were fastened boards standing edgeways like the skirting of our ordinary rooms, and marking out the size of each building. the walls of the huts were formed of small branches of twigs interwoven and plastered over with clay. the roof was made of straw or reeds like a thatched cottage. in size these huts were probably eighteen to twenty feet long, eight or ten feet broad, and about six feet high. they may have been divided into rooms, but there is no evidence of this. each was provided with a hearth formed of three or four slabs of stone. the number of huts in each settlement must have been considerable, in fact, they must have formed villages of no mean extent, for as many as forty, fifty, or even a hundred thousand piles have been found spread over a large extent of ground, forming the foundation of one such settlement. it is probable, however, that these were not so numerous when first erected, but were gradually added to as the population increased. this fact, along with many others, shows that these dwellings were inhabited for long periods of time, during which the population pursued their ordinary life in comparative peace and quietness in their island homes. such is, in brief, a general account of these remarkable structures. of course there were several variations in the methods of fixing these piles, one of which may be mentioned as showing the ingenuity of the builders. where the piles did not get a firm hold of the lake bottom, they carried out in boats or rafts loads of stones, which they threw down between the piles, thus firmly fixing them, just as modern engineers sometimes do for a similar purpose. as to the habits of the people who dwelt in these lake dwellings, we get a considerable amount of information from the various implements, refuse, etc., which fell through the imperfectly closed platforms into the lake, and which have been preserved in the mud at the bottom. they were fishers, hunters, shepherds, and agriculturists. skeletons of fish are found in large abundance, and in some settlements even the fishing nets, and hooks made of boar's tusks, have been discovered. then again there is an abundance of remains of the hunter's feast; bones of the stag, wild boar, bear, wolf, otter, squirrel, and many other wild animals are found in rich profusion, and often these are split and the marrow extracted. these ancient men, however, did not entirely rely on such precarious provision for their wants, but were so far advanced in civilization that they kept cattle and domestic animals of various kinds. they possessed dogs in great numbers, as well as cows, sheep, goats, and pigs, and in winter time had these housed on their settlements, as among the remains found are litters of straw, etc., which had evidently served as bedding for these animals. this, of course, necessitated the gathering of grass or other material for their food. they also cultivated wheat, barley, flax, and a number of other vegetable products. their methods of cultivation were no doubt very rude, consisting of a mere scratching of the ground with crooked branches of trees or with simple instruments made of stags' horn; but, nevertheless, they succeeded in getting very good results. among the relics which they have left are found stones for crushing corn, the grain which they used, and even the very cakes or bread which they made. there are also fruits, such as the apple, pear, nut, etc.; so that the bill of fare of prehistoric man was by no means contemptible. he had fish, game, beef, mutton, pork, bread, and fruit, besides a plentiful supply of water from the lake at his door. he was acquainted with the potter's art, and manufactured earthen vessels of various kinds. he seems to have produced two kinds--a coarser and a finer; the former made from clay mixed with a quantity of grains of stone, and the latter of washed loam. these he ornamented in an elementary fashion with certain lines and marks. some of the vessels he used have been found with a burnt crust of the porridge which he had been making adhering. as to his clothes, these were probably formed in great part from the skins of wild or domestic animals, but he also used fabrics made from flax, which he had learned to weave, as remains of cloth, twine, rope, etc., are not infrequently found in his dwellings. one prominent feature in the history of these lake dwellers is their gradual advance in the arts of civilization. while the main features of their settlements remain very much the same during the whole period of their residence, there is a gradual improvement in the details; the settlements become larger, and the implements, etc., better finished. and this is especially observable in the change of material which the dweller uses. in the earlier stages of his existence stone is the predominant feature, all his knives, saws, chisels, axes, etc., are made from this substance; but as time rolls on, one or two implements are found made of bronze, which is a mixture of tin and copper, and requires for its production a certain amount of knowledge and mechanical skill. gradually the number of bronze implements increases until eventually stone is superseded altogether, and improved forms of weapons of war make their appearance, and his work has a more finished look, arising from his improved implements. whether the manufacture of bronze was an original discovery of his own, or whether it was an importation from some more advanced race, is not certainly known; but as he undoubtedly had intercourse with the east, it is probable that the first bronze was imported, and that afterward he discovered the way to manufacture it himself. however this may be, it seems evident that the introduction of this material greatly aided his development. as stone gave place to bronze, so in the course of time this latter gave place to iron, probably introduced in the same manner some considerable time before the dawn of history; and this metal held its place until these habitations were finally abandoned. with regard to the religion of these lake dwellers, if they had any, nothing is known. from some curious objects formed somewhat like the crescent of the moon, which are found in considerable numbers, it has been supposed that they worshiped that body; but there seems to be really no evidence for this supposition, and these objects may only have been ornaments, or perhaps charms, fixed above the doors of their huts something after the manner of the horse shoe nailed over the door in modern times to keep away evil spirits. so far as can be inferred from the remains that have been examined, the same race seems to have inhabited these dwellings from their commencement to their end. there is no appearance of invasion from without; all seems continuous. probably his race came in early time from the east, and were a pastoral people, with flocks, herds, and domestic animals, and built their peculiar habitations to protect themselves from human enemies. certainly the arrangements were well fitted for the purpose in those days, when the club and the spear were almost the only weapons of offense. dr. keller, who has investigated this subject with great care, is of the opinion that these lake dwellers were a branch of the great celtic race. * * * * * [new england farmer.] how to raise turkeys. the best feed for young turkeys and ducks is yelks of hard-boiled eggs, and after they are several days old the white may be added. continue this for two or three weeks, occasionally chopping onions fine and sometimes sprinkling the boiled eggs with black pepper; then give rice, a teacupful with enough milk to just cover it, and boil slowly until the milk is evaporated. put in enough more to cover the rice again, so that when boiled down the second time it will be soft if pressed between the fingers. milk must not be used too freely, as it will get too soft and the grains will adhere together. stir frequently when boiling. do not use water with the rice, as it forms a paste and the chicks cannot swallow it. in cold, damp weather, a half teaspoonful of cayenne pepper in a pint of flour, with lard enough to make it stick together, will protect them from diarrhea. this amount of food is sufficient for two meals for seventy-five chicks. give all food in shallow tin pans. water and boiled milk, with a little lime water in each occasionally, is the best drink until the chicks are two or three months old, when loppered and buttermilk may take the place of the boiled milk. turkeys like best to roost on trees, and in their place artificial roots may be made by planting long forked locust poles and laying others across the forks.--_american agriculturist._ how to raise turkeys. keep the turkey hens tame by feeding them close to the house. have two or three barrels in sheltered corners containing plenty of straw or leaves for them to lay in. gather the eggs every evening, as turkey eggs are very easily chilled. keep the eggs in a woolen cloth on end and turn them every three days. set the first seven eggs under a chicken hen, as they get too old before the turkey hen will go to sitting. make a board pen ten or twelve feet square and twelve or fourteen inches high. put a coop in it and put your hen and turkeys in it. feed the hen with corn and the turkeys soaked wheat bread (corn meal will kill them), until they are a week old (i feed five or six times a day). then feed wheat until they are big enough to eat corn. give plenty of fresh water in a shallow vessel. keep the mother in the pen until they are large enough to fly over the top of the boards. let them out awhile about the middle of the day. shut them in at night. a turkey hen does not like to be shut up, but have a good big coop for her and she will go in. don't let the little turkeys get their backs wet until they are feathered. the turkey hen will sit down when night comes just where she happens to be, but if you drive her home a few times she will come herself after that. always feed them when they come home, no matter if they are full of "hoppers." have your no. pen in the orchard under an apple tree where it is shady. have the turkey hen's pen close to the chicken hen's pen, so that when the chicken hen weans her turkeys, they will soon learn to go with the turkey hen. give them a dose of black pepper in their feed every cold rain. and never, no never, get excited and in a hurry while working with turkeys if you don't want them to get wild and fly all over the plantation. three or four weeks before selling, feed all the corn they will eat. food hints. restrain your desire to count your young turkeys, and let them alone for twenty-four hours after they get into this world. remove them to a clean, airy, roomy coop, and give them boiled eggs, stale wheat bread crumbs just moistened with milk or water, "dutch" cheese, or a mixture of all these. for the first two weeks feed entirely with the eggs, bread, curds, cooked rice and cooked oatmeal. about the third week commence feeding cooked cornmeal; and from that on they may have any cooked food that would be suitable for chickens of the same age. season all food slightly with salt and pepper, and twice a week add a level tablespoonful of bone meal to a pint of feed. never feed any sour food or sloppy food of any kind, except sour milk, and never feed any uncooked food of any kind until after they have thrown out the red on their heads. feed often, five or six times a day, until after they are three months old; then, if insects are numerous, you may gradually reduce the number of meals per day to three or even two. after they are three months old they may be given wheat, cracked corn, etc., but not whole corn until they are five months old. keep the coops dry and clean, and the turkeys out of the dew and rain until they are fully feathered, and have thrown out the red. dampness and filth will kill young turkeys as surely as a dose of poison. for the first few days confine the poults to the limits of the coop and safety run; then, if all appear strong and well, give the mother hen and her brood liberty on pleasant days after the dew is off. if they get caught out in a shower, get them to shelter as soon as possible; and if they are chilled take them to the house and thoroughly dry and warm them. see that the little turkeys come home every night. the turkey mother must, for the first few nights, be hunted up and driven home. after they are three months old, turkeys are quite hardy, and may be allowed range at all times. if turkeys that are well cared for, and have always seemed all right, show signs of drooping when about six weeks or two months old, give douglas mixture in the drink or food, and add a little cooked meat to the food once a day.--_the practical farmer._ about sitting. for an ordinary place, select from a good breed (i prefer the bronze) a large gobbler and two or three hens. as soon as the warm weather comes, place about the barn in sheltered places two or three barrels on their sides, and in them make nice nests. in these the hens will lay. gather the eggs every day, keeping them in a cool place. when a box contains eggs mark it no. and begin to fill a second box, and when it contains eggs mark it no. and so continue. it is well to leave turkey hens on the nest two or three days, for they often lay one or two eggs after they begin to show signs of sitting. when you have decided to sit a hen, give her a good nest and eggs and at the same time give a common hen eight eggs. these, when hatched, are all to be given to the turkey hen. never try to raise turkeys with a domestic fowl. if you have no place free of grass, you can start turkeys with difficulty. feeding is of the greatest importance. for the first week i have found wheat bread moistened in water the most satisfactory. if you can feed them by sunrise for the first three or four weeks, you need lose hardly a bird. each evening try and call them nearer and nearer home, so that you will not be troubled with their wandering to the neighbors'. as early as possible train them to roost high, so as to be out of danger at night. bird dogs are often very destructive to turkeys, at times destroying a whole flock in a single night. fatten with corn. the turkey crop ought to be one of the most profitable on our farms. dr. g.g. groff. pennsylvania. graham. turkeys want care, especially for the first two or three weeks. i feed graham and wheat bread, made by scalding the flour, making a very stiff dough, and baking in a hot oven; soak over night in cold water. i also give them plenty of young onions, cutting them up with scissors. be careful not to let young turkeys out in the morning while the grass is wet. after the birds are two weeks old i feed wheat, but no corn until they are about a month old. i like hen mothers best, for turkey mothers are rangers, and do not take kindly to being kept in a coop. the bread will keep a week if made right, but do not soak more than will be wanted in a day, as it soon sours. i feed scraps from the table, such as potatoes and bits of meat cut very fine, but not much of the latter to young birds. i rarely lose a bird.--_mrs. e. reith, in homestead._ care and general management. in turkey raising the one who is the most careful and attentive to the small things is the most successful. the first laying of eggs should be set under a chicken hen. the turkey hen will, after a few days' confinement, lay another batch of eggs. a good-sized hen will cover and care for ten eggs; a turkey hen, seventeen. make a large, roomy nest of soft, fine hay--straw is too brittle and slippery. if there is danger of lice in the nest-box, sprinkle with water in which carbolic acid has been mixed in the proportion of eight drops to a half gallon of water. don't wet the eggs with this. after the eggs have been sat on one week, sprinkle with warm water every other day, until the last week; then every day, until they hatch. have the water clear, and use a flower or fine rose sprinkler. let the water be of the same temperature as the eggs, which can be ascertained by slipping a thermometer under the hen for a few minutes. this softens the shells, and as a little turkey is very weak, it is helped out easily, and is stronger than if working long to get out. let the little turkeys get well dried and strong enough to climb around the edges of their nest before taking them off. have a pen, say six feet square, built for them, and made tight at the sides clear down to the ground, to keep them from getting out and being chilled. put sand and fine gravel over the ground, and cover enough of it to afford shelter at night and when it rains. they may be kept in this pen the first four or five days, then let out after dew is off, and shut up before night. for the first few days' feed, nothing is better than clabber cheese or curd made by scalding clabbered milk until the curd separates and is cooked, then skimmed out and fed. mix a little black pepper with this every other day. meal must not be fed raw for several weeks, and then should be mixed with sour milk instead of water. bake the meal into bread by mixing it, unsifted, with sour milk, and adding a little soda and pepper. spinach, lettuce, onion tops and any other tender greens, chopped fine, are excellent food. from the time a turkey is hatched until it is ready for market it should have plenty of milk. give them clear water to drink, for milk is a food. see that the very young ones have milk and water in quite shallow dishes, for they are in danger of getting wet if the dish is deep. gather the little turkeys in at the first signs of rain, and they will soon learn to run and fly to their coop at the first drops. always shut them up at night, for they are early risers and will be out long before the dew is dried off. don't pen them too near the house. feed them at or near the same place all the time and they will learn to go there when hungry. give them a good feed at night and they will remember to come home for it. if the morning is dry, feed lightly and let them hunt the rest in the orchard and fields. keep the grass and weeds mowed around their pen and feeding places. mix slaked lime in the dust for them to take their dust bath in, and sprinkle the carbolic acid and water over and around their roosting pen. keep pails and kettles covered, for they will get drowned if they have half a chance, as they begin to fly so young. of course a turkey hen will take her young off, and care for them after a fashion, but the safest way to make them tame is to raise them where they may be cared for. even if the turkey hen hatches her last batch of eggs, it is a good plan to have a hen ready to take the little turkeys and slip them away at night. if she still stays on her nest give her or hen's eggs, and if she hatches them let her run with the chickens. they are not so tender or so easily led astray as turkeys are, nor as valuable.--_mrs. jas. r. hinds, in orange judd farmer._ * * * * * water as a therapeutical agent. by f.c. robinson, m.d. my experience in the use of water in almost every disease occurring in this climate has long since satisfied me that it is less objectionable and produces quicker and better results than any other treatment, and can be used when all other medication is contra-indicated. drinking water should be pure, uncontaminated by animal or vegetable impurities, and given _ad libitum_, unless, in rare instances, it should cause vomiting or interfere with the capability of digesting food. if children are comatose or delirious, as they frequently are in typhoid fever, give water to them regularly, or force it upon them, if they refuse to take it, as i was obliged to do with a child of six years just recovering from that fever. it is my custom to allow cold drinks of water in all cases of measles whenever patients desire it, and i am satisfied that it aids the early appearance of the rash, and certainly is cooling and grateful to the patient. hot drinks or vile and nauseous teas are unnecessary in this disease, and should be discarded as useless, odious, and disgusting. if congestion of the lungs or any intercurrent inflammation occurs, or the rash is much delayed, a hot water bath or the old reliable corn sweat will break up the complication with amazing rapidity, and if the head is kept cool, will not generally be unacceptable to the patient. hot baths reduce temperature by causing free perspiration afterward, and cold packs reduce it by cooling the surface sufficiently long to reduce the heat of the blood, and, if used judiciously, seldom fail of success. i have reduced the temperature four degrees in two hours by wrapping around a child a sheet wet with tepid water, and no other covering. cold packs are sometimes objectionable, because of their depressing effects, and should only be used to reduce high temperature and when there is no congestion or inflammation of any of the vital organs of the body. cold water poured in a small stream from a pitcher upon the head for five or ten minutes will often relieve headache, and is a benefit in all inflammatory brain diseases, if, at the same time, you can put the feet into hot water containing mustard or pepper. large enemas of warm water will care for spasmodic colic, and i have, in one instance, relieved strangulated hernia by the same method, and at another time the same result was accomplished by a large injection of warm linseed oil. i have often applied a cloth wet with cold water upon the throats of children suffering with spasmodic croup, with satisfactory results. i have seen infants suffering with diarrhea or summer complaint, sleepless, worrying, fretting, or crying from thirst, begging for water, and the mother or nurse afraid to give it more than a teaspoonful or two at a time, saying that it vomited everything it drank as soon as taken. i have often, when visiting such cases, called for a glass of cold water, and, to the surprise of the mother, would allow it to take all it could drink, which usually would be retained, and the child would soon be wrapped in a refreshing sleep. without medicine, a proper regulation of the child's diet would soon restore it to health again. the spasms of children, from whatever causes, or the eclampsia from uræmic poisoning, are often readily controlled when immersed in hot water or given a hot vapor bath or corn sweat. if the convulsions of children are accompanied by a high temperature, put them into water of ° and then gradually cool it down to ° or °, and then keep them in a room of the same temperature, with little covering. if the temperature rises, repeat the treatment as frequently as necessary, and i think you will not be disappointed in the results. scarlet fever and diphtheria, two of the most dreaded and formidable diseases of children, are largely shorn of their terrors when, in addition to an early and thorough medicinal treatment, the little patients are bathed in as warm water as the surface will allow frequently, or for thirty minutes wrapped in a warm, wet blanket, followed by warm, dry coverings, to maintain the perspiration that such treatment usually produces. it has proved to me a valuable aid in eliminating from the blood the specific poison which causes these diseases, and i can safely recommend it to your notice and trial. there is no disease more favorably influenced by this treatment than pneumonia, and in mild cases one daily warm bath or sweat, without medicine, will be sufficient to arrest this disease, and it is among the first things i usually order. if i find a child or infant with a temperature of ° to °, short, dry, and painful cough, dyspnoea, rapid pulse, great thirst, or vomiting, with dry crepitation in any part of the lung tissue, i order it rolled up in a blanket or sheet coming out of hot water, and in thirty minutes change it to warm, dry blankets, and soon the little fretful, worrying sufferer would rest in a quiet, peaceful sleep.--_peoria med. mo._ * * * * * on the health value to man of the so-called divinely beneficent gift, tobacco. by j.m.w. kitchen, m.d., new york. with perhaps the exception of heredity, the question of stimulants and narcotics in their relation to the physical welfare of the race is second to none in importance. with trifling exceptions, the whole world is addicted to their use. the universality of such use has led many to consider them a necessity to man, and that they are god's gifts to him, and, if rightly used, are of physical benefit. it may not be a perversion of judgment to consider that their widespread popular use is greatly due to the efforts of the race to gain anæsthesia for, and distraction from, those pains and punishments that are the inevitable sequence of departure from hygienic and social law on the part of the individual, his ancestry, and society in general. the taste for these things is acquired, not natural, though the acquisition may be through hereditary influence. an idea is held by a majority of even fairly intelligent individuals that there is a justifiable, harmless, and even beneficial use of these substances by the general public, though acknowledging that beyond a certain indefinite line this use becomes an abuse. i believe that there may occasionally be cases in which the physical benefits derived from their use outweigh the injury they inflict, but i think this use is very much less than is generally supposed, and if we can judge from the preponderance of evil effected by such use, these substances ought to be considered as the materialized curses of god rather than as beneficent gifts. the prevalent idea as to the beneficent nature of these substances i consider to be a delusion that can only be explained upon the hypothesis that there is a widespread lack of appreciation of the fact that, though they may have an immediate pleasant and agreeable effect upon the body, their injurious effects are cumulative, and are usually ultimate, and so distant as to be difficult of direct connection with their cause to ordinary observation. the more moderate the use of these substances, the more remotely is the effect removed from the cause and more difficult of detection. that the ordinary habitual, so-called moderate use of stimulants and narcotics, such as tea, coffee, tobacco, and alcohol, is, in the vast majority of cases, really an abuse, is a proposition that i think should be admitted by all who have given the subject an unbiased study. the idea that the user of tobacco and other injurious substances will be cognizant of the injury inflicted by habitual use in moderate or even excessive amounts is an undoubted fallacy. the daily, weekly, or monthly injurious effect may be entirely unobservable to even trained physicians, and yet the ultimate cumulative effect may be fatal. i can instance numerous cases of physicians directly fatally injured by the use of alcohol, who have never had the slightest cognizance of the fact; and i can also instance cases of grave disease from the use of tobacco where the patients never have believed that tobacco has been the cause of their troubles, even after a unanimous opinion to that effect has been expressed by a number of competent medical advisers. the habitual consumption of opium, in doses of any amount, is generally admitted by most people to be physically injurious outside of its strict medicinal application. moderate indulgence in alcohol as a beverage is beginning to acquire a very widespread evil reputation. but how about tobacco? tea and coffee we can confidently leave to the consideration of a somewhat remote posterity of a considerably advanced intelligence and elevated hygienic ideals. the relation of tobacco to the physical welfare of man can only be fairly estimated by viewing the subject in its broadest aspect; by considering its effects upon the race as a whole rather than in individual cases; by taking into consideration economical and other social conditions that at first sight might be considered as having little relevancy to the medical side of the subject. but there can be no just consideration of the matter otherwise. the direct deleterious effects of the immoderate use of tobacco are readily observable; but the great bulk of the evil physical effects due to the moderate use of this plant are of an intermediate nature and not directly noticeable; nevertheless, they are real, and worthy of medical attention. the plainly marked results following the use of tobacco in relatively large amounts seem to be due to quick and extreme interference with nutrition, and a diminution of function of all kinds, which may be represented by anything from a slight decrease of appetite and digestive ability up to a complete loss of function of almost any important organ. tobacco has stimulating as well narcotic properties, but as ordinarily used its stimulating effect appears to be slight as compared with its narcotic influence. in this respect it differs from alcohol, the use of which, owing to the usual method of introduction in large amounts through the stomach, produces directly, by stimulation, readily noticeable structural changes. but with tobacco the direct evil results are mostly of a functional character, and are more generally diffused, owing to the usual slow manner of introduction into the body. these two properties have an effect upon the body in moderate use as well as in immoderate use, the effect being simply in proportion to the quantity used, though the effects of moderate use may not be measurable by ordinary means. it is easy to see the effects of large amounts of tobacco in the stunted growth of adolescents; in functional cardiac disorders; in intellectual sluggishness, loss of memory, and color blindness; in loss of appetite, and other neuroses of motion, and marked blunting of various functions of sensation, and in degeneracy of descendants; but that lesser evils are produced must be proved mostly by inference, circumstantial collateral evidence, and analogy. the greater evils that are the outcome of a moderate use of tobacco are probably due to prolonged slight interference with nutrition, and consequent general decrease of vitality, which renders the individual more susceptible through indirect influence to the invasion of disease, and which lessens the capacity for productive effort. it is of course difficult, and perhaps even impossible, to accurately estimate the value of tobacco to the race; but let us glance at the pros and cons, and then each one can roughly estimate for himself. tobacco may be used medicinally, but it is a dangerous and uncertain remedy, and it probably has not one medicinal use that cannot be more suitably met by other remedies. one can readily imagine easier digestion as the result of the sedative influence of the after-dinner cigar upon a disquieted nervous system, especially if the coincident irritation of alcohol and coffee have need of correction; but it can also be imagined that in most of such cases the remedy has been the cause of and will further increase the disordered condition, and that nutrition of deficiently nourished nerve tissue is rationally indicated rather than partial narcotization. there then remains, so far as i can see, the solace of moderate anæsthesia and, occasionally, of occupation for idlers, as the only items that can be placed to the credit of tobacco. there certainly are individual cases where such usage may be more provocative of physical benefit than evil, but, before judging for the race as a whole, compute the other side of the question. tobacco injures the general health of the public through the economic loss caused by its consumption. the people of our country spend annually over seven hundred millions of dollars for tobacco--twenty per cent. more than is spent for bread. this sum represents only a minor part of the cost of the tobacco habit to the country. the crop is immensely exhaustive to the soil. its culture has blighted whole sections of fertile territory. in the time consumed by the producer and the trader in its production, manufacture, and sale, and by the consumer in its use, and by the general interference with vital activity and consequent decreased productive capacity, there is represented an almost unimaginable sum of money. certainly the people at large are not so well fed both as to quantity and quality, or so thoroughly clothed, or so hygienically housed that they can afford this gigantic economic waste. there can be little doubt that if the people had sufficient intelligence and moral strength to taboo tobacco, this comparatively senseless outgo would be largely devoted to supplying these and other necessities of an exalted health status. tobacco injures health through its moral effects. the tobacco habit is certainly a dirty and frequently a disgusting habit, and encourages other dirty practices. its use tends to make men cowardly, irritable in temper, and low in spirits. it blunts ideas of purity and courtesy, leading to invasion of the rights of others. it is presumed that few medical men would visit a delicate, sensitive patient after saturation with the "fragrant" effluvia of onions, but thousands whose systems are saturated with nicotine and who reek with nauseating odor do not hesitate to inflict their presence on sick or well. the time will come when the tobacco user will not be allowed to poison the atmosphere that is the common property of the public--will not be allowed to force the inhalation of nicotine upon the general public, to say nothing of being allowed to poison the infants and women in his own family. what would be said of a man who introduced poison in any degree into the food or drink of his child? is the poisoning of the household atmosphere by the ignorant, thoughtless, or selfish smoker morally more defensible? tobacco injures health through hereditary influence. the tobacco user begets, more certainly than the non-user, puny children with disordered nervous conditions. luckily for our race, the women, who have the most important prenatal influence in guarding its physical well-being, are practically non-users of the plant. the general health status of the race is improving, not because the use of tobacco or the indulgence in other questionable practices is harmless, but because, among other things, of the great advance in general intelligence and knowledge of hygienic law. a person, or the public in general, may practice an injurious habit, and yet more than counteract its influence by opposing beneficial practices. horace greeley said, "show me a drunkard who does not use tobacco, and i will show you a white blackbird." in this country, where dietetic drinking habits are not common in the family, the weakening of moral fiber by indulgence in tobacco is usually the introduction into the round of vicious indulgences, and thus directly or indirectly affects health. smoking induces dryness of the mucous membrane of the mouth and consequent thirst. the partially paralyzed nerve terminals want something more stimulating than water to afford relief. furthermore, blunted appetite induces deficient nutrition, and consequently there is a call for some "pick-me-up;" hence we find that the use of tobacco tends to the habitual use of alcoholic beverages, and there are very few habitual users of alcohol who escape without structural injuries to the body as well as perversion of its functions. decrease of vital activity in all the tissues of the body marks the use of tobacco. the tendency is toward functional paralysis, though occasional signs of stimulative irritation are to be noticed, especially in the respiratory passages. the interference with intellectual activity is marked. it is said that during a period of fifty years no tobacco user stood at the head of his class in harvard. the accumulated testimony of investigating observers is conclusive that, other things being equal, users of tobacco, in schools of all grades, never do so well in their studies as non-users. one head of a public school said he could always tell when a boy commenced to use tobacco by the record of his recitations. professor oliver, of the annapolis academy, said he could indicate the boy who used tobacco by his absolute inability to draw a clean, straight line. the deleterious effects of tobacco have become so clearly apparent that we find its sale to minors is prohibited in france, germany, and various sections of this country. it is somewhat a question if, at the present time, the race is not doing itself more injury by its use of tobacco than it is with alcohol, because of its more universal use, particularly by youth, and because of the respectability of the habit, which comes of its use by a certain intelligent part of the race, including teachers of morals and physics, and even temperance reformers. there is a widespread sentiment in existence that it is not a respectable thing to be even partly paralyzed by alcohol, but how few there are who consider narcosis as in any way connected with the use of tobacco. its effect is more diffused and masked, and is not so acutely serious in individual cases, but through its interference with vital activity, tobacco is probably more generally injurious to the race than alcohol. the editorial fiat of "too long" prevents a full exposition of the subject, but, in closing, let me say i hear millions of tobacco users ask, "why, then, was this plant given to man, if its general effects are so decidedly evil?" the question presupposes design in creation. without subscribing to this theory, or pretending to have solved the mystery of the presence of evil in the world, the answer may be suggested that the overcoming of many seductive evils becomes to man a means of his progressive higher development. of one thing i am convinced, that the physical development and welfare of man is interfered with in strict sequence to his consumption of substances that are unnecessary for his nutrition--stimulants and narcotics inclusive.--_medical record._ * * * * * acetic acid as a disinfectant. dr. f. engelmann, in _cent. f. gyn._, claims that acetic acid possesses equally as good antiseptic properties as carbolic acid; in fact, that it is to be preferred, as it is completely harmless, even if used in concentrated solutions, and that it is a valuable hæmostatic, an advantageous addition particularly in obstetrics. another important property is its ease of transition into the tissues, which, according to engelmann's experiments, is by far greater than that of all the other antiseptics. of bichloride it is well known that it forms an insoluble combination with albumen, and can therefore act only on the surface, while acetic acid extends into the deeper tissues with ease. acetic acid also affects the metal of the instruments, but not as severely as the bichloride; the forceps, for instance, may be placed for a quarter of an hour in an irrigator filled with a three per cent. solution of acetic acid without being injured. a pleasant effect of acetic acid is that it softens and lubricates the skin. the author generally used a three per cent. solution; at times he has made use of a five per cent. solution, which would easily cause a painful burning at sore places, so that he only used the latter strength in septic cases, as the three per cent. solution proved to be a satisfactory antiseptic for general purposes. * * * * * counter-irritation in whooping cough. by g.f. inglott, m.d. to combat this often distressing disease i have tried the administration of several medicines, namely, bromide of potassium, asafoetida, valerian, morphine, belladonna, etc., and i have very closely watched their effects, but none of them proved of much use. having observed, however, that during the late cholera epidemic some of the patients admitted into the hospital under my medical charge slept well, had their anxiety improved, and some of them ultimately recovered, after the application of a strong counter-irritation of the pneumogastric nerves in the neck, namely, between the mastoid process and the angle of the lower jaw, i tried the same treatment on whooping patients, and i have no hesitation in stating that the result was very satisfactory. i may quote one single case of the many i have had under treatment. a boy, aged twelve years, of weak constitution, was suffering from frequent and intense attacks of whooping cough. at a time the fits were so vehement that blood came out of his eyes and mouth. the case was a severe one, and i thought it would very likely end fatally. i prescribed several medicines, and even subcutaneous injections of morphine, but without any avail. i then tried for the first time the counter-irritation on both sides of the neck, and this means acted like magic. in four or five days the patient recovered, and was able to go to school. since that time i have been applying the same treatment, either on the right side only or on both, with the greatest benefit.--_br. med. jour._ * * * * * development of the embryo. at a recent meeting of the physical society, berlin, prof. preyer spoke on reflexes in the embryo. his researches extended over many classes of animals. as representing mammals, guinea pigs were chiefly used; and for reptiles, snakes; while in addition the embryos of fishes, frogs, mollusks, and other lower animals were also employed. but of all animals birds are most suitable for embryological observations, inasmuch as with due precautions the development of one and the same individual can be followed for a considerable time. birds' eggs can be incubated in a warm chamber, and by removing a portion of the shell and replacing it by an unbroken piece from another egg, it becomes possible to follow the daily development of the chick and to experiment upon it. as early as the ninetieth hour of incubation, spontaneous "impulsive" movements may be observed, taking place apparently without any external stimulus as a cause, and at a time when no muscles or nerves have as yet been developed. after the occurrence of these spontaneous movements, and at the earliest on the fifth day of incubation, movements are observed to result from the application of mechanical, chemical, and electrical stimuli. in order to observe these the eggs must be allowed to cool down until all spontaneous movements have ceased. from the tenth to the thirteenth day more complicated and reflex actions occur on the application of stimuli, as, for instance, movements of the eyelids, beak, and limbs; and if the stimuli are strong, reflex respiratory movements. these reflexes make their appearance before any ganglia have become differentiated. prof. preyer considered himself justified in concluding from this that ganglia are not essential for the liberation of reflex actions. he intends, on some future occasion, to give a more detailed account of these experiments, and of the conclusions which may be drawn from them. in the discussion which ensued the conclusions of the speaker were contested from many sides. * * * * * iridescent crystals.[ ] [footnote : abstract of the friday evening lecture delivered by lord rayleigh, f.r.s., at the royal institution, on april , .] by lord rayleigh. the principal subject of the lecture is the peculiar colored reflection observed in certain specimens of chlorate of potash. reflection implies a high degree of discontinuity. in some cases, as in decomposed glass, and probably in opals, the discontinuity is due to the interposition of layers of air; but, as was proved by stokes, in the case of chlorate crystals the discontinuity is that known as twinning. the seat of the color is a very thin layer in the interior of the crystal and parallel to its faces. the following laws were discovered by stokes: ( ) if one of the crystalline plates be turned round in its own plane, without alteration of the angle of incidence, the peculiar reflection vanishes twice in a revolution, viz., when the plane of incidence coincides with the plane of symmetry of the crystal. [shown.] ( ) as the angle of incidence is increased, the reflected light becomes brighter and rises in refrangibility. [shown.] ( ) the colors are not due to absorption, the transmitted light being strictly complementary to the reflected. ( ) the colored light is not polarized. it is produced indifferently, whether the incident light be common light or light polarized in any plane, and is seen whether the reflected light be viewed directly or through a nicol's prism turned in any way. [shown.] ( ) the spectrum of the reflected light is frequently found to consist almost entirely of a comparatively narrow band. when the angle of incidence is increased, the band moves in the direction of increasing refrangibility, and at the same time increases rapidly in width. in many cases the reflection appears to be almost total. [illustration: fig. general scheme fig. detail of lazy-tongs] in order to project these phenomena a crystal is prepared by cementing a smooth face to a strip of glass whose sides are not quite parallel. the white reflection from the anterior face of the glass can then be separated from the real subject of the experiment. a very remarkable feature in the reflected light remains to be noticed. if the angle of incidence be small, and if the incident light be polarized in or perpendicularly to the plane of incidence, the reflected light is polarized in the _opposite_ manner. [shown.] similar phenomena, except that the reflection is white, are exhibited by crystals prepared in a manner described by madan. if the crystal be heated beyond a certain point the peculiar reflection disappears, but returns upon cooling. [shown.] in all these cases there can be little doubt that the reflection takes place at twin surfaces, the theory of such reflection (_phil. mag._, sept., ) reproducing with remarkable exactness most of the features above described. in order to explain the vigor and purity of the color reflected in certain crystals, it is necessary to suppose that there are a considerable number of twin surfaces disposed at approximate equal intervals. at each angle of incidence there would be a particular wave length for which the phases of the several reflections are in agreement. the selection of light of a particular wave length would thus take place upon the same principle as in diffraction spectra, and might reach a high degree of perfection. in illustration of this explanation an acoustical analogue is exhibited. the successive twin planes are imitated by parallel and equidistant disks of muslin (figs. and ) stretched upon brass rings and mounted (with the aid of three lazy-tongs arrangements) so that there is but one degree of freedom to move, and that of such a character as to vary the interval between the disks without disturbing their equidistance and parallelism. the source of sound is a bird call, giving a pure tone of high pitch (inaudible), and the percipient is a high-pressure flame issuing from a burner so oriented that the direct waves are without influence upon the flame (see _nature_, xxxviii., ; proc. roy. inst., january, ). but the waves reflected from the muslin arrive in the effective direction, and if of sufficient intensity induce flaring. the experiment consists in showing that the action depends upon the distance between the disks. if the distance be such that the waves reflected from the several disks co-operate,[ ] the flame flares, but for intermediate adjustments recovers its equilibrium. for full success it is necessary that the reflective power of a single disk be neither too great nor too small. a somewhat open fabric appears suitable. [footnote : if the reflection were perpendicular, the interval between successive disks would be equal to the half wave-length, or to some multiple of this.] it was shown by brewster that certain natural specimens of iceland spar are traversed by thin twin strata. a convergent beam, reflected at a nearly grazing incidence from the twin planes, depicts upon the screen an arc of light, which is interrupted by a dark spot corresponding to the plane of symmetry. [shown.] a similar experiment may be made with small rhombs in which twin layers have been developed by mechanical force after the manner of reusch. the light reflected from fiery opals has been shown by crookes to possess in many cases a high degree of purity, rivaling in this respect the reflection from chlorate of potash. the explanation is to be sought in a periodic stratified structure. but the other features differ widely in the two cases. there is here no semicircular evanescence, as the specimen is rotated in azimuth. on the contrary, the colored light transmitted perpendicularly through a thin plate of opal undergoes no change when the gem is turned round in its own plane. this appears to prove that the alternate states are not related to one another as twin crystals. more probably the alternate strata are of air, as in decomposed glass. the brilliancy of opals is said to be readily affected by atmospheric conditions. * * * * * a new catalogue of valuable papers contained in 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[illustration] scientific american supplement no. new york, february , scientific american supplement. vol. xxxiii, no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. anthropology.--investigation of a mound near jefferson city, mo.--by a.s. logan.--prehistoric remains from the banks of the missouri river ii. biology.--new observations on the language of animals.--by m. de lacaze duthiers.--a lengthy examination of some facts in the language of animals, including birds and quadrupeds iii. botany.--electricity in agriculture.--by clarence d. warner.--the effect of currents of electricity upon the germination of seeds. --interesting experiments detailed, which can be easily repeated electricity in horticulture.--the effect of the electric light on vegetation, availability it may possess for the gardener pentapterygium serpens.--a himalayan flowering plant introduced in england about ten years ago.-- illustrations the perforation of flowers.--what insects do to promote the propagation of plants by perforating the flowers in search of honey.-- illustrations iv. chemistry.--a new laboratory process for preparing hydrobromic acid.--by g.s. newth.--simple synthesis of hydrogen and bromium boron salts.--boron sulphides and selenides and silicon selenide detection of peanut oil in olive oil.--a practical laboratory test for the above adulteration hydroxylamine.--recent preparation of this compound and its properties new boron compounds.--compounds of boron, phosphorus, and iodine recently prepared by m. moissan sapotin, a new glucoside.--by gustave michaud.--preparation of a new glucoside from almonds and other sources v. civil engineering.--completion of the mersey tunnel railway.--the penetration of the bed of the mersey river by a tunnel at the rate of feet per week.--details of the work vi. educational science.--chinese competitive examinations. --interesting details of the famous examinations of china.--fatal consequences to overworked competitors vii. electrical engineering.--high speed engine and dynamo.--a high speed compound engine, running at revolutions per minute, with direct-driven dynamo for electric lighting.-- illustrations viii. medicine.--the treatment of rattlesnake bite by permanganate of potassium, based on nine successful cases.--by amos w. barber, m.d.--the use of this powerful disinfectant, and the proper treatment and mode of applying it. ix. meteorology.--modification of our climate.--by joseph wallace.--climate epochs and the probabilities of the present climatic era.--changes within the records of man the eruption of krakatoa.--a graphic description of this catastrophe, involving the lives of , people x. military engineering.--the military engineer and his work.--by col. w.r. king.--a sibley college lecture, treating of the special problems in fortifications, sieges, and the more pacific work of surveys and explorations xi. mineralogy.--natural sulphide of gold.--by t.w.t. atherton.--a probable new occurrence of gold xii. natural history.--the living jerboa in the zoological garden of berlin.--a rare rodent from south africa, one seldom seen alive in captivity.-- illustrations xiii. naval engineering.--twenty-four knot steamers.--the possibility of fast ships for long voyages.--the prospects and difficulties xiv. railroad engineering.--a steam street railway motor.--a noiseless motor built of steel on trial in chicago.-- illustration xv. sanitary engineering.--some means of purifying water.--different filtering processes and the subsidence treatment of water xvi. technology.--action of caustic soda on wood.--by m.h. tauss.--direct experiments on the action of lye on wood at various pressures burning brick with crude oil fuel.--the use of petroleum in brick kilns.--its advantages, cleanliness, and cheapness. chlorine gas and soda by the electrolytic process.--the decomposition of common salt solution into chlorine and caustic soda on the commercial scale how enameled letters are made.--the manufacture of separate enameled letters as conducted in london.-- illustrations how mechanical rubber goods are made.--hose, corrugated matting, packing, and jar rings.--processes of their production * * * * * the living jerboa in the zoological garden of berlin. like other strangely formed quadrupeds, the jerboas are counted among the curiosities of the animal kingdom, and as such are described in natural history; but, nevertheless, there has never been a good exhibition of them, for the simple reason that live jerboas are seldom seen in europe, as they usually die during the journey hither or soon after their arrival. after some hesitation i decided to purchase a pair that i happened to find mentioned in the price list of mr. c. reiche, of alfeld, as one of the most interesting specimens obtained during his expedition to south africa the year before; but i, also, found the sensitiveness and delicacy of the jerboa very trying, for the short journey from alfeld to this city caused the death of the female and reduced her mate to such a condition that when it arrived there seemed little hope that it could ever be utilized for scientific research or artistic life studies. [illustration: jerboa in the zoological garden of berlin.--drawn from life by g. mutzel.] my anticipation and pleasure were changed to vexation and grief. the most careful nursing--the stiff, weak little legs were dipped into and rubbed with french brandy--and a warm pen with a dry sanded floor directly over a heater, did their work. as the new-comer got on his feet again my hope gained new life, and now our jerboa is my delight. it is, indeed, a curious animal. one who saw it only in the day time asleep would scarcely know what he had before him, for he would see little more than a mass of soft, bright sandy hair. the coming of the keeper with the dish of food and the unfastening of the door of the cage bring life to the ball of hair in the corner; a part of it is unrolled and the long, black-tipped tail with two lines of hair is laid out on the ground, and then on each side of it a leg is run out which is nearly as long as the tail and is provided with blunt, smooth, hoof-life nails; and, finally, the head and body are distinguishable and the animal stretches out comfortably on its back in the sand. the fine-skinned, hairless ears still hang limp, the eyes are half closed and the short fore legs are crossed under the chin. but now the animal gets on its legs by an elastic swing, and its ears are raised and its eyes wide open, so that we can see that the latter are large and dark, with long eyelashes. then the jerboa raises himself to his full height and playfully measures his cage by one bound from corner to corner. soon after, the fresh food receives due attention, the animal either jumping toward it in rabbit fashion or crawling slowly on all fours. when it has reached its goal it again assumes the upright position, in which it is evidently most comfortable, and begins to eat it in his own peculiar way; that is, sitting on his hind legs he quickly seizes a piece of bread, turnip or other food in his fore paws and conveys it to his mouth, apparently indifferent to the nature of the food before him. he never takes anything directly in his mouth; even the grass on a piece of turf that i had given to him as an experiment was not eaten as it would have been eaten by other animals, but was first plucked with the fore paws. if we notice the position of the mouth, far back on the under side of the head, we will understand that the jerboa could not take his food in any other way. besides this, nothing of special interest has been observed in this nocturnal creature, but he, of course, lives more regularly and quietly than if his mate had lived. one who knows anything about the structure of animals' bodies need not be told that the jerboa is a rodent. one glance at the peculiar shape of his head would assure him of that. the form of the rest of its body, especially its long hind and short fore legs, give unmistakable proof that it is related to the jumping rodents; it belongs, in a wide sense, to the family of the jumping mouse, the scientific name (dipodidea, two-footed) of which is very significant, as the very short fore legs are usually carried close under the chin and are scarcely noticeable when the animal is in its normal position, and are of little use when it moves about. the hind legs are very strong, and when going at full speed the jerboa takes jumps that measure from eight to ten yards, according to the unanimous testimony of various witnesses. the jumping mouse of north america, which is somewhat larger than an ordinary mouse, is, according to brehm, also as swift as an arrow or a low-flying bird. this exceptional velocity is not all that reminds us of a bird, for there is also a strong resemblance in the formation of certain parts of the bodies of the two creatures; but, after consideration, this should not seem strange, because in animal organisms similar means are employed to accomplish similar ends. it is only natural that there should be peculiarities in the construction of the limbs and skulls of the dipodidea with their bird-like movements and bird-like sharp-sightedness, that are usually found only among birds. the consistency between the construction of their bodies and their mode of life is a beautiful example of fitness; only by extraordinary quickness of movement and sagacity could the little defenseless plant-eaters maintain the struggle for existence in the barren steppes and deserts. the formation of the bodies of the different members of the family varies according to their needs. the jerboa is the largest member of the family. very little is known of his life when free; it being known only that the jerboas are widely spread over the whole of southern africa, and are nocturnal burrowers of the steppes. during the rainy season they remain in a sort of winter sleep.--_dr. l. heck, in the illustrirte zeitung_. * * * * * new observations on the language of animals. by m. de lacaze duthiers, of the institute of france. i had occasion in a note published several years ago in the _revue scientifique_ to mention a parroquet which i have since continued to observe, the manifestations of whose intelligence are both interesting and instructive. many acts of birds are difficult of interpretation. to speak only of their songs, the meanings of most of the innumerable varieties of sounds which they produce, and of their diverse warblings, escape us completely. it is not possible to find the meaning of these things except by forming suppositions and hypotheses, or by catching the connections between cries and acts. but instances of the latter kind are extremely rare in comparison with the great majority of the manifestations made by animals. thus, to select examples which every one can observe, when a canary bird is warbling in its cage and becomes deafening, or when a lark rises straight up in the air and _incantat suum tirile tirile_--sings its _tirile tirile_--as linnæus picturesquely expresses it; when a tomtit, leaping from branch to branch of a willow or among the reeds, repeats its florid warblings; when a raven croaks; when a blackbird whistles--what significance can we attach to their songs and their cries? certainty is impossible, and we can only form more or less plausible hypotheses concerning the interpretation of them. the parrot furnishes us one more aid in this matter than other birds, and this helps us, to a certain extent, in overcoming the difficulty of interpretation. it has an articulate voice, and when we have taught it a few words, the meaning which it gives them may be better divined by us according to the tone and the rapidity or slowness of its utterance. this permits us to discover the feelings that move it, for we can better judge from an articulate sound than from one that is merely musical. much has been written on the language of animals. it is neither my desire nor my intention to repeat here all that may have been said on this subject. it would take too long and would be of no use. i have often witnessed facts that may be of interest to those who are occupied with the mental manifestations of animals. i will simply relate them; and of such as are already known, i will merely mention them anew, admitting in advance a priority for others which i do not demand for myself. there can be no doubt that animals communicate their impressions by an inarticulate voice. common sense and the most superficial observations are opposed to the negative of this proposition. but when a canary bird warbles till it stuns us, or a nightingale sings in the shadows on the fine nights of june, can we follow and discover the significance of those modulations--now sharply cadenced, now slowly drawn out, and ending with a trill long and accurate enough to challenge the most skillful musician? all the poets of every country have constantly sung of the songs of philomela. but their fervent and enthusiastic verses cast little light on the value of the nightingale's song. it is said that the male sings for the entertainment of the sitting female, but there is no proof of the assertion. the note warning of the approach of danger is easier to recognize. the bird utters a short, hoarse cry, and repeats it with a succession of _trrre, trrre_, which is impossible to mistake. when we hear this cry we may be sure that an enemy is near. music gives way to a cry of distress and warning, and the female leaves her nest if the sounds become piercing. what do we know of the gobbling of the turkey, which the whistling and the cries of children excite? they are doubtless responses to those challenges; but what do they mean? the crowing of the cock, recurring regularly at fixed hours, has some signification, but we cannot comprehend it. if on a fine afternoon in autumn the cock crows, and repeats his strain between two and four o'clock, the countrymen in some places will say there will be a fog on the morrow, and they are generally not mistaken. hens do not mistake his notes either; when a leader of the troop, coming upon a spot rich in food, utters his peculiar chuckle, they run from all around to share the find with him. it is evident that the cock has called them and they have understood him. these facts indicate that there is some definite sense in this inarticulate language; and examples of it, taken from other groups, might be multiplied. the dog, intelligent animal as he is, manifests his affection on meeting his master, with peculiar cries which vary with the intensity of his joy. no one could confound these notes of pleasure with those which he utters when he is angrily driving away a beggar, or when he meets another dog of unpleasant appearance and puts himself in the position of attack. an interesting study of the voice of the dog on guard may be made in the country at night. if another dog barks in the distance, the house dog answers in a peculiar manner. he gives a few growls, stops, seems to listen, begins again, very often getting answers; and, after two or three interruptions, he terminates his barking with abrupt yelps, loud at the beginning and long drawn out, and gradually dying away. this ending of his cries is habitually accompanied by his raising his head and throwing it back. i have often, when within the house, on hearing the watch dog bark in this way, opened the window to assure myself on the subject, and distinguished, as i could not do with the windows closed, the voice of another watch dog barking in the same way in the distance--the barkings of the two dogs alternating, one answering the other. there is in such cases an evident communication of impressions. one of the dogs, having had his attention aroused by some unusual noise, has transmitted his impression to the other, as sentinels posted at intervals call out theft warnings one to another. i have often repeated this observation during the long evenings of winter. another example, little known in thickly populated countries, is drawn from a curious scene which i witnessed during a winter passed in perigord noir. we had remarked that for several nights the three watch dogs, a young and an old male and a bitch, howled often toward midnight, but in a peculiar way. one night in particular, during their tedious concert, just as we had got to sleep, they mingled with their cries howlings like those they would have uttered if they had been beaten, with a shading hard to define, but which we perceived plainly; and we remarked that, leaving their kennel in the avenue that led up to the lodge, they had come to close quarters with one another at the gate, with alternating howlings and plaintive cries. inquiring in the morning for the cause of these singular cries, the peasants told me that a wolf had passed, and predicted that it would return. they said, too, that a neighbor's hunting bitch had disappeared, and its bones had been found in the fields near a wood. we were awakened again about midnight by the cries of the dogs, and the scene was renewed. informed as we now were of the nature of what was going on, we ran to one of the windows, whence we could see, in the clear light of the moon, all that passed. the three dogs were cowering against the gate, the oldest one howling by the side of the others, while the younger one and the bitch were exposed at intervals to the attacks of another animal, browner than they, and of about their size, without defending themselves, but moaning as if they were undergoing a vigorous correction. frightened, doubtless, by the opening of the blinds of the first story above him, the strange animal had gone away and was sitting in the middle of the road. we could only see that he had straight ears. while we were going down to get a gun the visitor came back to his charge on the dogs, which had begun howling after he left them, and resumed the cries significant of chastisement when they were attacked again. for some reason, perhaps because he heard the click of the gun, the foe drew back and sat down in a garden walk, concealed by a bunch of shrubbery. the three dogs, notwithstanding our reiterated urging, were no more disposed to pursue him than before. if the assailant had been a dog they would have rushed upon him, but they stayed cowering at the gate and howled distressfully. the bitch was most affected, and they all seemed paralyzed by fear. it is said in the country that bitches are especially liable to be attacked by wolves. it was so here. the most certain feature in the matter was the terror of the animals. they were capable of resisting the attack three times over. the young dog was a savage one, and passers-by were afraid of the bitch; but that night they were terrorized, and all incapable of defending themselves. their cries were therefore due to the same cause as in the preceding night--the presence and attacks of the wolf. i could not have realized their meaning if i had not been a witness of the scene--that is, i could not have correlated the cries and the acts. a shot at the animal behind the bushes was followed by a hoarse cry. he was hit, and ran; but, in spite of our urgings, the dogs stayed at the gate and only stopped howling. under any other conditions, upon the signal of the shot they would all have started in pursuit of the wounded animal. a wolf came to the farm during the last winter ( - ) and attacked the same bitch. he would have carried her off, for he had seized her by the throat, if we could judge from the stifled cries she uttered; but this time he found with her a new watch dog--a mountain bitch from the pyrenees--of a breed that attacks the wolf and the bear. the wolf would have been caught if he had not run away. he did not return, for he had been attacked, and learned what he had to deal with. the pyrenean breed furnishes excellent watch dogs. i knew one of remarkable traits. at evening he would go round the house, giving two or three growls at each door. with his head raised he seemed to listen to his fine voice, then he would start again and go to another door. he seemed desirous to show those who were observing him that he was attending to his post as guardian. he then went away in silence along the walk, through a dark, rising hedgerow, leaping the slight hillock, yelping toward the wood. he listened, yelped again, and went in. there was never any failure in this performance, but every evening as night was coming on he began his round, which no one had taught him. it was all done in his function as a guard. it would be hard to determine what his yelps meant, but there were in them an inflection, a sonorousness, and a continuance quite different from those he uttered when pursuing a passer-by or when going to meet a person coming toward the house. every one who has a watch dog is able to tell by the sound of his barking when a person is coming up, and usually what sort of a visitor it is. the peasants' dogs of the southwest of france dislike the country millers, because of the long whips which they are always carrying and snapping, and with which the dogs, running after them, are often struck. from as far off as the snapping of the whip can be heard, the dogs come to wait for the millers and pursue them; and it is easy to recognize when the millers are passing, by the behavior of the dogs. there is in this also a significance, at once aggressive and defensive, in the cries which one can, by giving a little attention, soon learn to distinguish. another example of the reality of the various meanings of the cries of the dog under different circumstances is afforded by the companies that collect around a female in heat. i have a very intelligent and experienced brach hound, the same which with the bitch had to face the attack of the wolf. he amuses me much at my country lunches. hunting dogs which have been much with their masters at lunch do not like to have the drinking glass offered them. this dog was much afraid of the glass, and i had only to present it to him at lunch time to make him keep his distance. i used to keep my door open at lunch, for the amusement of observing how i could make him stop exactly at the threshold without stepping over it. if he had passed over it i could always send him back by casting toward him a few drops of water from the bottom of the glass after drinking. sitting, as was his habit, on the sill of the door, with the tip of his muzzle never extending beyond the plane of the panels, he would follow my motions with the closest attention, reminding me, if i failed to give him a sign of attention, by a discreet, plaintive cry, that he was there. but if i touched my glass, he would spring up at once; if i filled it, he would put himself on guard, utter a kind of sigh, sneeze, lick his lips, yawn, and, shaking his ears briskly, make little stifled cries. then he would grow impatient, and more and more watchful and nervous. when i lifted my glass to my lips he would draw back, working gradually nearer to the farther door, and at last disappear and hide. one who was looking at him without seeing me could tell by his wails and his attitude the level and position of my glass. when the glass was horizontal, i could see only about half of his head, with one eye regarding me fixedly, for that was usually the critical moment--the one, also, when the wails and restraints were most demonstrative of the anxious fear of my poor animal. when we dine in the kitchen, which is on the ground floor, the dogs are usually all put out. there are four of them, three young and not experienced, and this old, sagacious brach hound. he insists on coming in, and, to gain his purpose, tries to have the door opened. although no person may be coming up the walk, he dashes down it barking, all the others going along too and yelping with him; then he stops, remains a little behind after having got the others out of the way, and, turning his head from moment to moment, looks to see if the door has been opened, for we generally go to it to see who has come. in that case the feigned attack is successful, and the dog, who has evidently meant to give the alarm so as to have the door opened, comes in at once and claims a place at the table. he has accomplished his end, for the door is usually shut without paying attention to his having got in. i have frequently witnessed this stratagem, and when, during my kitchen dinner, i suddenly hear the dogs yelping after the brach hound has begun, i am pretty sure that nobody is in sight. i have forgotten where i found the next story of an old dog who was also very sagacious. hunting dogs, when they grow old, become rheumatic, or are at least debilitated with pains. we know, too, that they crave heat, and get as near the fire as possible--a craving which increases as they grow older. one such dog, older than the others, and slower in getting into the lodge on returning from the hunt, was often crowded away from the fire by the other livelier dogs getting all the best places before him. finding himself thus turned out in the cold, he would dash toward the door barking, when the others, supposing it was an alarm, would rush away too, while the old rheumatic went to the fire and selected a place to suit him. it is not necessary to dwell upon the intelligence shown by such acts. but it is hardly contestable that the old animal, who knows how to play such tricks upon his less experienced companions, deceives them by his intonations, while he is well aware that no enemy is approaching the house; but he does it scientifically, by the inflections of his voice, as a man speaking to other men would do in announcing the arrival of an imaginary enemy. inarticulate cries are all pretty much the same to us; their inflections, duration, pitch, abruptness, and prolongation alone can inform us of their purpose. but experience and close attention have shown us the connection of these variations with the acts that accompany or precede them. animals evidently understand these inflections at once. we cannot better compare the language of animals than with what takes place in a pleasant sport, a kind of pantomime of the voice or language which many youth doubtless understand, and which i venture to refer to here to aid in more easily conceiving of the communication of thought among animals by sounds which seem to us all alike. when i was engaged in hospitals, the evenings in the guard room were sometimes enlivened by the presence of a companion who excelled in humorous mimicry. he would represent a man in liquor who had stopped at a fountain that flowed with a gentle sound, somewhat like that of his own hiccough. a single oath, pronounced in different tones, was sufficient to enable us to comprehend all the impressions, all the states of mind through which this devotee of bacchus passed. the oath, at first pronounced slowly and with an accent expressing relief, represented a feeling of satisfaction, with shadings of prolonged exclamation which it would be hard for one to imagine without suggestion. the continued flowing of the fountain made our drunken man impatient, and he wanted it to stop. this state of mind was translated by a new modulation of the same word. in a little while the gurgling of the fountain produced astonishment. was it possible that he, with all the liquid he had imbibed, could vomit so much and for so long a time? this mental condition was expressed by a new modulation of the same oath. the first movement of surprise over, resignation follows, and our man decides to wait patiently for the end. a period of half lethargy was easily represented by the slowness and weakness of the man's voice while living up to this decision; but when he comes out of this sleepy condition and hears the fountain again, he is possessed with fear; he cannot understand the flood he is pouring out--he dares not move--he believes he is lost. gradually the fumes of the liquor pass away, and, his mistake being recognized, the drunkard is taken with a laughing and a gayety which are indicated by the same oath repeated in tones corresponding with the satisfaction he is then enjoying. this making the series of impressions a man passes through comprehensible by a single word, varied in pronunciation and utterance, is very like the language of animals, which is always the same, and the significance of which is given by variety of intonations corresponding with sensational conditions. the mewing of the cat is always the same; but what a number of mental conditions it expresses! i had a kitten whose gambols and liveliness entertained me greatly. i understood well, when it came up to me mewing, what the sound meant; sometimes the kitten wanted to come up and sleep in my lap; at other times it was asking me to play with it. when, at my meals, it jumped on my knees, turned round, looked at me, and spoke in a coaxing and flattering way, it was asking for something to eat. when its mother came up with a mouse in her jaws, her muffled and low-toned mew informed the little one from a distance, and caused it to spring and run up to the game that was brought to it. the cry is always the same, but varied in the strength of the inflections and in its protraction, so as to represent the various states of mind with which my young animal is moved--just as it was with the drunken man in the mimicry scene. these facts are probably well known to all observers of animals. we have seen that this tonality of the watch dog's cries is competent to indicate that a person is coming to the house. we find similar cries of warning uttered by birds. when i was a professor in the faculty of lille, i frequently visited the well known aged professor of physics, m. delezenne. he had a working room at the end of a garden, in which a laughing mew wandered. from the time that any one came in till he went out, this bird made the vocal explosions to which it owes its name; and the good professor was certain, without ever being mistaken, that somebody was coming to his laboratory. he was notified. my jaco in paris has a warble that answers the ringing of the bell. if we have not heard the bell, we are notified by jaco of its ringing, and, going to the door, find some one there. i have been told of a parrot belonging to the steward of a lyceum which had heard the words "come in," when any one rang the bell. he never failed to cry, "come in," when the bell moved, and the visitor was embarrassed at seeing nobody after having been invited to open the door. instances in which the cries of birds had an incontestable and precise signification are numerous; let me refer to a few of the best known. the cackle of a hen, after having laid an egg and left her nest, is decidedly characteristic. her clucking when she is impelled to sit on her eggs, or when she is calling her chicks, is no less demonstrative. there is not a farmer who does not recognize it and understand it. in these things we see the relation between the tone of the prating or cluck of the hen and her acts. but when a nightingale sings all night, or a goldfinch whistles, or a raven croaks, we cannot so easily interpret the significance of their inarticulate sounds. the finch calls its mate by uttering a few notes followed by a long trill. matches of a barbarous character, based on this habit, i were held in the north of france while i was living at lille, between and . i do not know whether they have been suppressed or not, but the laws for the protection of animals ought to take cognizance of them. the gamesters put out the eyes of the male finches, and made them, thus blinded, compete as singers, for which purpose they brought their cages into proximity. when the birds heard and recognized one another's voices, they made their appeal to the female; the one that renewed his amorous trills most frequently, protracted them longest and to the last, gained the prize. the bird that was declared victor received a medal amid the applause of a large and enthusiastic crowd; and considerable wagers were staked upon the result. i have heard that these poor blinded birds sometimes fell down exhausted with singing, and kept on calling the absent female till they died, not being willing to yield to a rival, who on his side was also keeping up his equally useless appeals. these finch contests were suggested after the meaning of the song of the birds was learned. but when these birds, which are more usually isolated--whence they have been named _fringilla coelebs_, or celibates--hop around our houses and also utter their amorous trills at another than the mating season, they are evidently not calling the female. should we not then seek to determine by the tone whether their call, which is always the same, is amorous or not? in countries where flocks of turkeys are raised one can learn very quickly from their gobblings when they have captured a hare. if they meet him standing still or lying down, they form in a circle around him, and, putting their heads down, repeat continually their peculiar cries. the hare remains quiet, and it is sometimes possible to take him up, terrorized as he is in the midst of the black circle of gobbling beaks and heads. the language of the turkeys is at that time incontestably significant. it is warlike, and similar to that of the males when they are fighting. in the present instance they have joined for war, and they make it on the frightened hare. my jaco, like all parrots, which are excellent imitators, pronounces a few words and repeats them over and over again. such birds amuse us because the words they know sometimes happen to be ludicrously fitting. a bird of this kind had been struck by the note sounded by the wind blowing into a room through a crack in the glass work whenever a certain door was opened; and he had become so perfect in his imitation that they sometimes, on hearing the noise, went to shut the door when it was not open. jaco formerly belonged to a very pious old lady who was accustomed to say her litanies with another person. he had caught the words "pray for us," in the invocations to the several saints, and said them so well as sometimes to deceive his learned mistress, and cause her to think she was saying her litanies with two colleagues. when jaco was out of food, and any one passed by him, he would say, "my poor cocotte!" or "my poor rat!" in an arch, mawkish, protracted tone that indicated very clearly what he wanted, and that his drinking cup was empty. there was no doubt in the house as to his meaning; and whenever one heard it he said: "he has nothing to eat." he was exceedingly fond of fresh pits of apples and pears, and i was in the habit of collecting them and keeping them to give him. so whenever, as i came near him, i put my hand into my pocket he never failed to say: "poor cocco!" in a supplicating tone which it was impossible to mistake. a sugar plum is a choice morsel to him. he can tell what it is from a distance when i hold it out in my fingers; and when i give it to him he cannot restrain himself if it has been any considerable time since he has had the delicacy. usually, after having made the first motion to get it, as if he were ravished and wanted to express his joy in advance, he would draw back before taking it, and say, in a comical tone, "hold, my poor cocotte!" his manner of thanking in advance is likewise amusing. the expression of his eyes and the pose of his head are all in accord with the tone of his exclamation. when he tastes the plum he utters a series of _ahs_, and produces a kind of warble by prolonging some of his notes and shortening up others. we find in these examples, without doubt, that the articulate voice makes us better able to judge the meaning of the impressions that are moving the animal than inarticulate cries, or merely musical sounds. when jaco met a child for whom he had a great affection, he would promenade on his perch, or turn the wheel, spreading out his tail and ruffling the feathers of his head, while his eyes grew red with excitement if the child was too slow in bestowing the accustomed caress. then he would stop, bend down his head, and, looking at his friend, say pleasantly, "jaco," in a tone and with a manner quite in contrast with the pronunciation of the same word when he was hungry. it is not the word he speaks that is of interest; he might have been taught another, and it would have been the same; but it is the tone. in this case, too, the articulation gives an easier clew to the meaning the bird seeks to express, having a meaning according to the manner of pronouncing it, than any isolated, simply musical sound, like the song of the nightingale, canary bird, and warbler. this became evident to me, not from observing animals for a few moments without seeing them again, but from studying them continuously. jaco did not like solitude, and was talkative and fond of being caressed, like all of his kind. one day, when there was no one in the country house, all having gone out into the garden or the fields, i heard him saying over what few words he knew, in different inflections. i went quietly into the room where he was, without being seen; but he heard my steps, although i walked in very cautiously, hoping to surprise him. he ceased his chatter, listened, and, after a silence, pronounced "jaco" in a low tone, drawing out the end of the word. he listened again, and repeated the word in the same tone; then, after another silence, repeated it with a rise of the voice. i continued observing him, and, as he heard no one, he raised his tone gradually, repeating the same word, and ended at last with a genuine cry of distress. the people ran in from without, supposing something had happened to him. he then repeated his name in a lower tone, which seemed to indicate his satisfaction at finding his isolation ended. i went in myself, and his prattle unmistakably betrayed his gladness at being no longer alone. is there not in this an act of real intelligence? while alone, the parrot entertained himself by talking; but when he heard a sound he hoped at first to see some one come; and when no one answered him, he raised his voice, as a person would do who calls, and, getting no reply, cried out louder and louder till he was heard and answered. the meaning of the differences of intonation is as evident in this case as in that of the drunken man. a parrot raised in the south had learned to swear in the local _patois_. being fond of coffee, he was sometimes given a spoonful, which he would come awkwardly up to the table to drink with his master. one day the master, not thinking of his bird, had already added cognac to his coffee, and gave the parrot the accustomed spoonful. the parrot took a swallow of it, and, in his surprise at the novel taste, raised his head and repeated the oath in a tone that excited laughter in all who were present. the cause of his surprise being discovered, he was soothed, and then took his usual ration with evident signs of contentment. the mimicry of language in this case clearly represented the shade of the new impression he felt. jaco is very timid. in the evening, when he is put to roost in a close and dark room, he is afraid of the shadow of his perch that is cast by the light we carry in our hand; he eyes it, and utters a low cry, which stops when the candle is blown out and he cannot see the shadow any longer. he stands in dread of blows in the bottom of his cage, because, having a wing broken, he cannot fly, and is afraid of falling. feeling his weakness, his language has a different tone from the usual one. large birds flying in the sky above him annoy him greatly, and we can all tell by his voice when such a bird is near or flying over. he inclines his head and chatters in a low tone as long as the bird is in sight, paying no attention to anything else. turkeys and hens announce the approach of a bird of prey in a similar manner. we find in the facts which we have related, as well as in many others which are cited respecting the ways and habits of parrots, proofs of a remarkable intelligence. these creatures are distinguished by the unlimited affection which they bestow upon some persons, as well as by their excessive dislikes, which nothing can explain. jaco conceived an extraordinary dislike for a maid who, although she took good care of him, was in the habit of washing the bottom of his cage under a faucet. he afterward discarded another person, whom he had liked so much that she could do what she pleased with him, even to passing her hand over his back and taking him by the tail, holding him in her hands, or putting him in her apron--caresses of a kind that parrots do not usually permit. nothing astonished him or offended him. he proved very inconstant toward her, and now, while better disposed toward the other girl, he is furious against this one. a third miss has come to capture his affection; and when he has been left asleep, or resting in his cage, he has always the same word, but different in the inflection wheedling, angry, or nearly indifferent, as either of the three persons comes near him. jaco's pronunciation is scanned in many meters. only one young student has had the privilege of retaining his affection unmarred. jaco had been left in the country for a whole week in the winter. alone and isolated, he was taken care of by a person who was not constantly with him. the young student, accompanied by a tutor, came to pass a few days in the house. at the sight of the youth, jaco, surprised, called out, "momon! momon!" "it was affecting," they wrote me, "to see so great signs of joy." i have also myself witnessed similar signs of joy at the coming of the student. jaco's speech at such times is always in harmony with his feelings. in the pleasant season jaco's cage is put outdoors; and at meal times, knowing very well what is going on within, he keeps up a steady course of suppliant appeals for attention. his appeals cease at once if i go out with fruit in my hand, and if i go toward him he utters a prattle of joy that sounds like musical laughter. these manifestations indicate that he is happy at seeing that he has been thought of. i close these anecdotes, as i began them, by repeating that animals communicate their impressions, and the feelings that move them, by various modulations of their inarticulate cries, which are incomprehensible to us unless we have succeeded by attentive observation in connecting them with the acts that follow or precede them. we have also seen that the articulation of a few words learned by parrots aids us greatly in learning the meaning of these different inflections. the extension of these studies would furnish much of interest; but further observations should be made upon the same animals for a longtime continuously, relating especially to their peculiar instincts as manifested by their various cries. we might then, by comparing and relating acts and cries, reach the point of comprehending and perhaps fixing the meaning in many cases where we are now in ignorance. every one has noticed a few facts, and has interpreted and related them, but much is still wanting for the co-ordination of them in the point of view of the signification of the language and communication of animals among themselves. it has not been made in a general sense. --_translated for the popular science monthly from the revue scientifique_. * * * * * modification of our climate. by joseph wallace. every now and then some weather sage predicts extremely cold winters, and another ventures to say that the sun is gradually losing heat and in time arctic cold will prevail over the globe. whatever may have been the changes during the vast cycles of time prior to the advent of man, or whatever may be the changes in the time to come, one thing is quite certain; that our climate has been much modified within the past two or three thousand years. "there have been fifteen climatic changes since the beginning of the glacial age, each change lasting , years, and each change reversing the season in the two hemispheres, the pole which had enjoyed continuous summer being doomed to undergo perpetual winter for , years, and then passing to its former state for an equal term. the physical changes upon the earth's surface during the past , years modified the changes of climate even in the arctic regions, so that the intense cold of the former epochs was much modified during the latter epochs." reckoning these climatic changes in their order, we had entered the epoch of a more genial temperature about fifteen hundred years ago; and if no disturbing change takes place during the present epoch, we may reasonably expect a gradual modification of our winters for nine thousand years to come. the changes to intense cold from perpetual summer during the greater part of the glacial period are supposed to have been caused by the high temperature of the north pole as compared to that of the south pole, owing to the distribution of land around the two, the south having almost none. dr. croll thinks it was caused by the varying inclination of the earth's axis, which produced the relative position of the two poles toward the sun to be periodically reversed at distant periods. dr. james geikie agrees with croll on the reverse of seasons every , years during certain periods of high ellipticity of the earth's orbit. but it may be asked, "how could the fauna and flora propagate themselves under such conditions?" the flora itself at the quaternary age was of extreme vigor. we know this from the little which is left us, but more especially from the presence of a large number of herbivorous animals--stags, horses, elephants, rhinoceros, etc.--which animated the plains and valleys of europe and america at the same time. evidently they could not have lived and propagated themselves without abundant vegetation for nourishment and development. that which has deceived the adherents of the glacial theory, as understood in its absolute sense, is, they have generally placed a too high estimate on its extent and intensity. it needs but a little effort of the reasoning powers to come to the conclusion that the earth had cooled to the degree that all animal and vegetable life could exist upon it, and that a portion of the earth's surface permanently covered with snow and ice was absolutely indispensable to the existence, perpetuity, and well-being of animal and vegetable life. again, they have attributed to the glaciers the rocks, gravels, and other material which they have found spread here and there long distances from the mountains. the transportation of the so-called erratic rocks has appeared inexplicable in any other way, and the piles of rock and gravel have been considered so many _moraines_, that is, deposits of diverse material transported by the glaciers. they do not regard the probability of other agents taking the place of glaciers, and undervalue the moving power of water. water in liquid state has often produced analogous effects, and it has often been the error of the glacialists to confound the one with the other. the erratic rocks and the moraines are undoubtedly the ordinary indications of the ancient gravels, but, taken isolatedly, they are not sufficient proof. in order to convince they should be accompanied with a third indication, which is the presence of striated rocks which we find in the neighborhood of our actual glaciers. when all these signs are together then there is hardly a possibility of error, but one alone is not sufficient, because it can be the effect of another cause. no doubt the temperature was really lower at the quaternary age and at the epoch generally assigned to man's advent in european countries, but the difference was not so great as some say. a lowering of four degrees is sufficient to explain the ancient extension of the glaciers. we can look on this figure as the maximum, for it is proved to-day that humanity played the main _role_ in the glacial phenomena. the beds of rivers and the alluvia are there to tell that all the water was not in a solid state at that time, that the glaciers were much more extended than in our days, and that the courses of the rivers were infinitely more abundant. when this is understood we can reasonably reduce the extension of the ancient glaciers, the lowering of the temperature at the quaternary age, and account for the uninterrupted life of the fauna and flora. however, we must not fall into the opposite excess and assert, as some have done, that the glacial period is comparatively recent, the traces of which are too plain and fresh in some localities to assign to it an age prior to man, and that the temperature has rather lowered itself since this epoch. the ancient extension of the glaciers has been followed by a corresponding growth and extension of animal life, thus proving that the permanence of glaciers is a wise provision and absolutely essential to man and the high orders of animals and vegetation. the ancient extension does not prove alone that it was much colder than in historic times, for the animals themselves are proof of this. at that time the plains of europe, and of france in particular, were animated by herds of reindeer, gluttons, camels, and marmots, which one does not find to-day except in the higher latitudes or more considerable heights. the mammoth and rhinoceros are no exception to this, for naturalists know they were organized to live in cold countries. space will not permit us to pursue this point further, or speculate on the probable climatic conditions of the ice age; but we can carry ourselves back a few thousand years and describe the climate of europe and neighboring countries of africa and asia. herodotus describes the climate of scythia in terms which would indicate in our day the countries of lapland and greenland. he shows us the country completely frozen during eight months of the year; the black sea frozen up so that it bore the heaviest loads; the region of the danube buried under snow for eight months, and watered in summer by the abundant rains which gave to the river its violent course. the historian adds that the ass cannot live in scythia on account of the extreme cold which reigns there. the following century aristotle makes the same remarks concerning gaul. his contemporary, theophrastes, tells us that the olive tree did not succeed in greece more than five hundred furlongs from the sea. we can assure ourselves that both the ass and the olive thrive in these countries at the present day. three centuries later, cæsar speaks frequently and emphatically of the rigor of winters and early setting in of cold in france, the abundance of snow and rain, and the number of lakes and marshes which became every moment serious obstacles to the army. he says he is careful not to undertake any expedition except in summer. cicero, varro, possidonius, and strabo insist equally on the rigor of the climate of gaul, which allows neither the culture of the vine nor the olive. diodorus of sicily confirms this information: "the cold of the winters in gaul is such that almost all the rivers freeze up and form natural bridges, over which numerous armies pass quite safely with teams and baggages; in order to hinder the passengers to slip out upon the ice and to render the marching more secure, they spread straw thereon." virgil and ovid insist on the severity of cold in the regions of the danube. the first describes the inhabitants of these miserable countries withdrawing themselves into caves dressed with the skins of wild beasts. ovid, who had passed several years of his life in that region, is more precise in his description. he says the wine has changed itself here (black sea) into a solid frozen mass; one gives it to drink by pieces. fearing of being accused of poetic exaggeration he appeals to the testimony of two ancient governors of moesia, who could establish the facts like himself. the author who would give such accounts of the black sea in our days would risk his reputation for veracity. italy, too, experienced its part of the cold in early days. virgil tells us of the snows being, heaped up, rivers which carried ice along, the sad winter which split the stone and bound up the course of large streams, and all this in the warmest part of italy, at the base of the walls of taranto. heratius affirms that the soracte, a neighboring mountain of rome, was whitened with thick snow, rivers frozen, and the country covered with snow. to-day the snow stays very little upon the soracte and never in the country around rome. during the four or five centuries which followed, writers speak of the severity of climate in northern italy, the lagoons on the adriatic being frozen over. algiers was much colder then than now. the danube, rhine, and other rivers in europe, the nile in africa, the amazon in south america, the mississippi and missouri in north america, had quite different volumes two thousand years ago than their present actual ones, and they especially rolled much greater masses of water. there is everything to show a modification of climate in our own days. if this goes on in the future as in the past, there will be a marked difference in the temperature two or three hundred years from now. even a degree in a thousand years would effect a great change in the course of time. the lowering of four degrees established the ancient extension of glaciers, though it did not interrupt animal or vegetable life. fifty-four of the fifty-seven species of _mollusca_ have outlived the glacial age, and all our savage animals--even a certain number which have disappeared--date equally from the quaternary, and were contemporary with the great extension of the glaciers.--_popular science news_. * * * * * the eruption of krakatoa. before the year physical geographers, in speaking of the most disastrous volcanic eruption on record, referred first, in point of time, to the celebrated eruption of vesuvius, in a.d. , when the cities of herculaneum, pompeii and several smaller towns on the slope of the mountain were destroyed by lava or buried under a mass of pumice stones and ashes; second to that of hecla and skaptar jokull, contiguous mountains in iceland, in , when two enormous lava streams, one miles wide and over ft. deep and the other scarcely inferior, flowed, the first, miles and the other , till they reached the sea, pouring a flood of white hot lava into the ocean, destroying everything in their paths and killing in the waters of the ocean the fish, the mainstay of the inhabitants, who were reduced by the disaster, directly or indirectly, to less than five-sixths of their former strength; and third to that of galungung, in , which devastated such an immense area in java; but all the eruptions known besides were as mere child's play to the terrible one of krakatoa in . if the reader will examine the map of the east indies he will find represented in the straits of sunda, which lie between sumatra and java, the little island of krakatoa. in maps made before he will hunt in vain for the name, for like bull run before , it was then unknown to fame, though navigators who passed through the straits knew it as a beautiful tropical isle, with an extinct volcanic cone in the center. in the beginning of , however, the little well behaved island showed symptoms of wrath that boded no good to the larger islands in the vicinity. noted for the fine fruits with which it abounded, it was a famous picnic ground for towns and cities even miles away, and when the subterranean rumblings and mutterings of wrath became conspicuous the people of the capital of java, batavia, put a steamboat into requisition and visited the island in large numbers. for a time the island was constantly in a slight tremor, and the subterranean roar was like the continued but distant mutterings of thunder, but the crisis was reached august , at o'clock a.m. it was a beautiful sunday morning and the waters of the straits of sunda were like that sea of glass, as clear as crystal, of which john in his apocalyptic vision speaks. the beauty that morning was enhanced by the extraordinary transparency of the tropical air, for distant mountain ranges seemed so near that it seemed possible to strike them with a stone cast from the hand. only the mysterious rumblings and mutterings of the pent up forces beneath the island disturbed the breathless calm and silence that lay on nature--the calm before the terrible storm--the mightiest, the most awful on record! it burst forth! sudden night snatched away day from the eyes of the terrified beholders on the mainland, but the vivid play of lightnings around the ascending column of dust penetrated even the deep obscurity to a distance of miles. this awful darkness stretched within a circle whose diameter was miles, while more or less darkness reigned within a circle with a diameter three times as great. within this latter area dust fell like snow from the sky, breaking off limbs of trees by its weight miles distant, while in batavia, miles away from the scene of the disaster, it fell to the depth of several inches. the explosions were so loud as to be distinctly heard in hindostan, , miles away, and at batavia the sound was like the constant roar of cannon in a field of battle. finally the whole island was blown to pieces, and now came the most awful contest of nature--a battle of death between neptune and vulcan; the sea poured down into the chasm millions of tons, only to be at first converted into vapor by the millions of tons of seething white hot lava beneath. over the shores miles away, waves over ft. high rolled with such a fury that everything, even to a part of the bedrock, was swept away. blocks of stone, of tons weight were carried two miles inland. on the sumatra side of the straits a large vessel was carried three miles inland. the wave, of course growing less in intensity, traveled across the whole indian ocean, , miles, to the cape of good hope and around it into the atlantic. the waves in the atmosphere traveled around the globe three times at the rate of miles per hour. the dust from the volcano was carried up into the atmosphere fully twenty miles and the finest of it was distributed through the whole body of air. the reader doubtless remembers the beautiful reddish or purple glow at sunrise and sunset for fully six months after august, --that glow was caused by volcanic dust in the atmosphere interfering with the passage of the sun's rays of the upper part of the solar spectrum, more manifest at sun rising and setting than at other times during the day, because at these periods the sun's rays have to travel obliquely through the atmosphere, and consequently penetrating a very deep layer, were deprived of all their colors except the red. the loss of life was appalling. the last sight on earth to , people was that of the awful eruption. engulfed in the ocean or covered with heaps of ashes, a few hours after the eruption commenced the awful work was done, and that vast multitude had vanished from off the face of the earth. the fact that in the neighborhood of the mountain there was a sparse population accounts for there not being even a far greater loss of life. notwithstanding the awfulness of volcanic and earthquake phenomena, there is some silver lining to the dark clouds. they prove that the earth is yet a _living_ planet. centuries must pass away before it will become like the moon--a dead planet--without water, air or life. our satellite is a prophecy indeed of what the earth must eventually become when all its life forces, its internal energies, are dissipated into space.--_granville f. foster, min. sci. press_. * * * * * pentapterygium serpens. this is one of five species of himalayan plants which, until recently, were included in the genus vaccinium. the new name for them is ugly enough to make one wish that they were vacciniums still. pentapterygium serpens is the most beautiful of the lot, and, so far as i know, this and p. rugosum are the only species in cultivation in england. the former was collected in the himalayas about ten years ago by captain elwes, who forwarded it to kew, where it grows and flowers freely under the same treatment as suits cape heaths. sir joseph hooker says it is abundant on the sikkim mountains at from , to , feet elevation, and that it usually grows on the stout limbs of lofty trees. in this it resembles many of the rhododendrons of that region, and it has been suggested that they are epiphytic from force of circumstances, not from choice. on the ground they would have no chance against the other vegetation, which would strangle or starve them out. remove them from this struggle for existence, and they at once show their preference for rich soil and plenty of it. all the pentapterygiums have the lower part of the stem often swelling out into a prostrate trunk, as thick as a man's leg sometimes, and sending out stout branching roots which cling tightly round the limbs of the tree upon which it grows. these swollen stems are quite succulent, and they serve as reservoirs of moisture and nourishment. in the wet season they push out new shoots, from which grow rapidly wands three or four feet long, clothed with box-like leaves, and afterward with numerous pendulous flowers. these are elegant in shape and richly colored. they are urn-shaped, with five ribs running the whole length of the corolla, and their color is bright crimson with deeper colored v-shaped veins, as shown in the illustration of the flowers of almost natural size. they remain fresh upon the plant for several weeks. the beautiful appearance of a well grown specimen when in flower may be seen from the accompanying sketch of the specimen at kew, which was at its best in july, and remained in bloom until the middle of september. [illustration: pentapterygium serpens (flowers nearly natural size)] p. rugosum is also grown as a greenhouse plant at kew, where it has been in cultivation about twenty years. it has larger leaves and a more bushy habit than p. serpens, while the flowers are produced in fascicles on the old wood. they are as large as those here figured, but differ in color, being whitish, with brown-red v-shaped marks. both species may be propagated from cuttings. the plants thrive in sandy peat, and they like plenty of moisture at all times.--_w. watson, in the gardeners' magazine_. [illustration: pentapterygium serpens (flowers deep crimson)] * * * * * the perforation of flowers. the subject of the relations and adaptations which exist between flowers and insects does not appear to excite as much popular attention as many other branches of natural science which are no more interesting. sprengel, darwin, and hermann muller have been the chief authors in giving us our present knowledge and interest in the study; sir john lubbock has helped to popularize it, and prof. w. trelease and others have carried on the work in this country. the perforation as well as the fertilization of flowers has received attention, but there is a wide field for further study for those who have leisure to pursue it, as it requires much time and patience, as well as closeness and accuracy of observation. the accompanying figures, from drawings by mr. c.e. faxon, show a few characteristic perforations and mutilations, and also represent two of the principal kinds of insects which make them. any one interested in the subject will find an excellent brief review of the work already done, a fair bibliography, and a list of perforated flowers in professor l.h. pammel's paper on the "perforation of flowers," in the _transactions of the st. louis academy of science_, vol. v., pp. - . the general beauty of flowers is usually not greatly marred by the perforations except in a few cases, as when the spurs of columbines and corollas of trumpet creepers are much torn, which frequently happens. the great object of the perforations by insects is the obtaining of the concealed nectar in an easy way. very naturally, flowers which depend on insect agency for fertilization rarely produce seed when punctured if they are not also entered in the normal way. perforating is only practiced by a small number of species of insects, and many but not all of the perforators do so because their tongues are too short to reach the nectar by entering the flower. some obtain nectar from the same kind of flower both in the normal way and by perforating. the chief perforators of flowers, in this part of the continent at least, appear to be some kinds of humble bees (bombus) and carpenter bees (xylocopa). these insects have developed an unerring instinct as to the proper point to perforate the corollas from the outside, in order to readily get at the nectar. the holes made by the humble bees and by the carpenter bees are usually quite different and easily distinguished. the humble bees have short, stout, blunt jaws, ill adapted for cutting, and the perforations made by them are apparently always irregular in shape, and have jagged edges. it has been stated that the humble bees often bore through the tubes of their corollas with their maxillæ, but in all cases observed by me the mandibles were first brought into use in effecting an opening. the noise caused by the tearing is often audible for a distance of several feet. the true jaws of the carpenter bees are not any more prominent or better adapted for making clean-cut perforations than those of the humble bees; but behind the jaws there is a pair of long, sharp-pointed, knife-like, jointed organs (maxillæ) which seem to be exclusively used on all ordinary occasions in making perforations. the inner edges of these maxillæ are nearly straight, and when brought together they form a sharp-pointed, wedge-shaped, plow-like instrument which makes a clean, narrow, longitudinal slit when it is inserted in the flower and shoved forward. the slits made by it are often not readily seen, because the elasticity of the tissues of some flowers causes them to partially close again. when not in use the instrument can be folded back, so that it is not conspicuous. the ordinary observer usually sees no difference between the humble bees and the carpenter bees, but they may be readily distinguished by a little close observation. [illustration: the perforation of flowers. . xylocopa and heads of male and female. . bombus and head. . dicentra spectabilis, showing punctures. . ribes aureum. . ligustrum ibota. . Æsculus glabra. . lonicera involucrata. . caragana arborescens. . andromeda japonica. . buddleia japonica. . mertensia virginica. . rhododendron arborescens. . corydalis bulbosa.] no doubt, in some of the recorded cases of perforations, carpenter bees have been mistaken for humble bees. the heads of all our northern humble bees are rather narrow, retreating from the antennæ toward the sides, and with a more or less dense tuft of hair between the antennæ. the abdomen, as well as the thorax, is always quite densely covered with hair, which may be black or yellowish or in bands of either color. with possibly one or two exceptions, the only species i have seen doing the puncturing is bombus affinis, cresson. the carpenter bees (xylocopa virginica) of this region have the head very broad and square in front, and with no noticeable hair between the antennæ. the heads of the male and female differ strikingly. in the male the eyes are lighter colored and are hardly half as far apart as in the female, and the lower part of the face is yellowish white. the female has eyes smaller, darker, and very far apart, and the whole face is perfectly black. the abdomen is broad, of a shining blue-black color, very sparsely covered with black hairs, except on the first large segment nearest the thorax. on this segment they are more dense and of the same tawny color as those on the thorax. but it is particularly from the character of the head that the amateur observer of the perforators may soon learn to distinguish between a xylocopa and a bombus as they work among the flowers. it is also interesting to know that the xylocopas are not so inclined to sting as the humble bees, and the males, of course, being without stinging organs, may be handled with impunity. among other insects, honey bees have been said to perforate flowers, but authentic instances are rare of their doing much damage, or even making holes. i have only recorded a single instance, and in this a honey bee was seen to perforate the fragile spurs of impatiens. when searching for nectar they quite commonly use the perforations of other insects. wasps and other allied insects also perforate for nectar. my only observations being a vespa puncturing cassandra calyculata, an andrena (?) perforating the spurs of aguilegia, and adynerus foraminatus biting holes close to the base on the upper side of rhododendron flowers. the holes made by some of the wasp-like insects are often more or less circular and with clean-cut edges. the ravages committed by larvæ, beetles and other insects in devouring flowers, or parts of them, do not properly come under the head of perforations. the question as to the cause of the handsome corollas of the trumpet creeper (tecoma radicans) being so often split and torn has been accounted for in various ways in published notes on the subject. humming birds and ants have been blamed, the humming birds being such constant visitors of these flowers that it really seemed as though they must be the authors of the mischief. i have often watched them when they appeared as though they were pecking at the blossoms, but careful examinations, both before and after their visits, always failed to show any trace of injury. finally, on july , , i was rewarded by seeing a number of baltimore orioles vigorously pecking at and tearing open a lot of fresh blossoms, and this observation was afterward repeated. that the oriole should do this was not surprising, considering its known habits in relation to some other flowers. j.g. jack. [mr. jack adds a list of sixteen plants whose flowers he has seen punctured by the carpenter bee and seventeen others whose flowers were punctured by the humble bee. he names more than thirty other flowers which he has found perforated without having seen or identified the authors of the mischief.--ed.]--_garden and forest_. * * * * * electricity in horticulture. the influence of electricity upon vegetation has been the subject of numerous investigations. some have been made to ascertain the effects of the electric current through the soil; others to ascertain the effect of the electric light upon growth through the air. among the latter are those of prof. l.h. bailey of the cornell university agricultural experiment station. in bulletin no. of the horticultural department is given an account of experiments with the electric light upon the growth of certain vegetables, like endive, spinach, and radish; and upon certain flowers like the heliotrope, petunia, verbena primula, etc. the results are interesting and somewhat variable. the forcing house where the experiments were carried on was × ft., and was divided into two portions by a partition. in one of these the plants received light from the sun by day and were in darkness at night. in the other they received the sunlight and in addition had the benefit of an arc light the whole or a part of the night. the experiment lasted from january until april during two years, six weeks of the time the first year with a naked light and the balance of the time with the light protected by an ordinary white globe. it is not the purpose here to enter into any great details, but to give the general conclusions. the effect of the naked light running all night was to hasten maturity, the nearer the plants being to the light the greater being the acceleration. the lettuce, spinach, etc., "ran to seed" in the "light" house long before similar plants in the dark. an examination of the spinach leaves with the microscope showed the same amount of starch in each, but in the electric light plants the grains were larger, had more distinct markings and gave a deeper color with iodine. with lettuce it was found that the nearer the plants were to the light the worse the effect; and conversely those furthest away were the best developed. cress and endive gave the same results. in the case of the latter, some of the plants were shaded from the light by an iron post, and these grew better and were larger than those exposed to its direct rays. the average weight of eight plants in full light was . grains, as opposed to an average of six plants in the shade of . grains. radishes were strongly attracted to the light and moved toward it during the night. during the day they straightened up, but moved again toward the light at night. the plants nearest the lamp made a poor growth and were nearly dead at the end of six weeks. averaging the weight of plant, of top and of tuber, it was found that those grown in the dark were heavier in every instance than those grown in the light; and the percentage of marketable tubers from the light-grown plants was twenty-seven, as opposed to seventy-eight in the dark. chemical analyses showed the plants in the light to be more mature than those in the dark, although they were much smaller. dwarf peas showed the same facts, those in full light being smaller than those in the dark. the former bloomed a week earlier than the latter, but the production of seed was less, being only about four-sevenths as great. further experiments were made by excluding the sun during the day and exposing the plants to the diffused electric light only. in all cases, with radishes, lettuce, peas, corn, and potatoes, the plants died in about four weeks. only a little starch and no chlorophyl was found in the plants deprived of sunlight and only receiving the electric light. thus the experiments with a naked light showed conclusively that "within range of an ordinary forcing house the naked arc light running continuously through the night is injurious to some plants." in no case did it prove profitable. experiments with the light inclosed in a white globe and running all night were different in their results. the effect was much less marked. lettuce was decidedly better in the light house; radishes were thrifty but did not produce as much as in the dark house. a third series of experiments with the naked light running a part of the night only were also made. radishes, peas, lettuce, and many flowers were experimented upon. the lettuce was greatly benefited by the light. "three weeks after transplanting (feb. )," we are told, "both varieties in the lighthouse were fully per cent. in advance of those in the dark house in size, and the color and other characters of the plants were fully as good. the plants had received at this time ½ hours of electric light. just a month later the first heads were sold from the light house, but it was six weeks later when the first heads were sold from the dark house. in other words, the electric light plants were two weeks ahead of the others. this gain had been purchased by ¾ hours of electric light, worth at current prices of street lighting about $ ." this experiment was repeated with the same results. in the second experiment the plants receiving eighty-four hours of electric light, costing $ . , were ready for market ten days before the plants in the dark house. the influence of the light upon color of flowers was variable. with tulips the colors of the lighted plants were deeper and richer than the others, but they faded after four or five days. verbenas were injured in every case, being of shorter growth and losing their flowers sooner than those in the dark house. "scarlet, dark red, blue and pink flowers within three feet of the light soon turned to a grayish white." chinese primulas seven feet from the light were unaffected, but those four feet away were changed. lilac colors were bleached to pure white when the light struck them fairly. an elaborate series of tables of the effect of the light is given in the paper. the author believes it possible that the electric light may be used some day to pecuniary advantage in floricultural establishments. these experiments naturally open up many questions. those which will be of most importance to the practical man will be such as relate to the benefits to be derived from the use of the electric light. that electricity has a great effect upon vegetation can no longer be denied. what remains now is to ascertain how to use the force with the most economy and to the best advantage. if by its use early vegetables will be made earlier, bright flowers be made brighter, it will be a question of only a short time before it will come into general use. to the student of plant physiology there are also many questions of interest, but into these it is not the intention to enter. prof. bailey's general conclusions are, in part, as follows: "there are a few points which are clear: the electric light promotes assimilation, it often hastens growth and maturity, it is capable of producing natural flavors and colors in fruits, it often intensifies colors of flowers and sometimes increases the production of flowers. the experiments show that periods of darkness are not necessary to the growth and development of plants. there is every reason, therefore, to suppose that the electric light can be profitably used in the growing of plants. it is only necessary to overcome the difficulties, the chief of which are the injurious influences upon plants near the light, the too rapid hastening to maturity in some species, and in short the whole series of practical adjustments of conditions to individual circumstances. thus far, to be sure, we have learned more of the injurious effects than of the beneficial ones, but this only means that we are acquiring definite facts concerning the whole influence of electric light upon vegetation; and in some cases, notably in our lettuce tests, the light has already been found to be a useful adjunct to forcing establishments.... it is highly probable that there are certain times in the life of the plant when the electric light will prove to be particularly helpful. many experiments show that injury follows its use at that critical time when the planetlet is losing its support from the seed and is beginning to shift for itself, and other experiments show that good results follow from its later use.... on the whole, i am inclined toward siemens' view that there is a future for electro-horticulture." joseph p. james. washington, jan. , . * * * * * electricity in agriculture. by clarence d. warner. it is well known that currents of electricity exist in the atmosphere. clouds are charged and discharged. there is a constant change of electricity from earth to air and from air to earth, the latter being the great reservoir for all electricity. hills, mountain peaks, trees, high chimneys, spires, in fact all points elevated above the earth's surface assist greatly in charging and discharging the atmosphere. again, if two iron rods are driven into the earth and connected by a copper wire with an electrometer in the circuit, the instrument is almost immediately affected, showing that currents of electricity are running through the ground. now, what is the function of these atmospheric and ground electric currents? many scientists are agreed that certain forms of precipitation are due to electrical action; but my observations have led me to believe conclusively that electricity is a potent factor in the economy of nature, and has more to do with the growth and development of plants than has hitherto been known. davy succeeded in the decomposition of the alkalies, potash and soda, by means of electric currents. in our laboratories, water and ternary compounds are rapidly decomposed by the battery, and we may reasonably suppose that that which is effected in our laboratories by artificial means takes place in the great laboratory of nature on a grander and more extended scale. plant food is carried throughout the plant by means of the flow of sap; these currents circulate through all the rootlets and center, as it were, in the stalk, carrying their tiny burdens of various elements and depositing them in their proper places. that this phenomenon of circulation is due to electricity cannot be doubted. most plants grow more rapidly during the night than in the day. may not the following be a reason for this? we have already mentioned how electric currents pass from air to earth and _vice versa_; at night the plant is generally covered with dew and the plant itself becomes a good conductor, and, consequently, currents of electricity pass to each through this medium, and during the passage convert soil elements into plant food and stimulate the upward currents to gather up the dissolved elements and carry them to their proper places. from the time electricity became a science, much research has been made to determine its effect, if any, upon plant growth. the earlier investigations gave in many cases contradictory results. whether this was due to a lack of knowledge of the science on the part of the one performing the experiments, or some defect in the technical applications, we are not prepared to say; but this we do know, that such men as jolabert, nollet, mainbray and other eminent physicists affirmed that electricity favored the germination of seeds and accelerated the growth of plants; while, on the other hand, ingenhouse, sylvestre and other savants denied the existence of this electric influence. the heated controversies and animated discussions attending the opposing theories stimulated more careful and thorough investigations, which establish beyond a doubt that electricity has a beneficial effect on vegetation. sir humphry davy, humboldt, wollaston and becquerel occupied themselves with the theoretical side of the question; but it was not till after that practical electroculture was undertaken. williamson suggested the use of gigantic electrostatic machines, but the attempts were fruitless. the methods most generally adopted in experiments consisted of two metallic plates--one of copper and one of zinc--placed in the soil and connected by a wire. sheppard employed the method in england in and forster used the same in scotland. in the year hubeck in germany surrounded a field with a network of wires. sheppard's experiments showed that electricity increased the return from root crops, while grass perished near the electrodes, and plants developed without the use of electricity were inferior to those grown under its influence. hubeck came to the conclusion that seeds germinated more rapidly and buckwheat gave larger returns; in all other cases the electric current produced no result. professor fife in england and otto von ende in germany carried on experiments at the same time, but with negative results, and these scientists advised the complete abandonment of applying electricity to agriculture. after some years had elapsed fichtner began a series of experiments in the same direction. he employed a battery, the two wires of which were placed in the soil parallel to each other. between the wires were planted peas, grass and barley, and in every case the crop showed an increase of from thirteen to twenty-seven per cent. when compared with ordinary methods of cultivation. fischer, of waldheim, believing atmospheric electricity to aid much in the growth and development of plants, made the following tests: he placed metallic supports to the number of about sixty around each hectare ( . acres) of loam; these supports were provided at their summits with electrical accumulators in the form of crowns surmounted with teeth. these collectors were united by metallic connection. the result of this culture applied to cereals was to increase the crop by half. the following experiment was also tried: metallic plates sixty-five centimeters by forty centimeters were placed in the soil. these plates were alternately of zinc and copper and placed about thirty meters apart, connected two and two, by a wire. the result was to increase from twofold to fourfold the production of certain garden plants. mr. fischer says that it is evidently proved that electricity aids in the more complete breaking up of the soil constituents. finally he says that plants thus treated mature more quickly, are almost always perfectly healthy, and are not affected with fungoid growth. later, n. specnew, inspired by the results arrived at by his predecessors, was led to investigate the influence of electricity on plants in every stage of their development; the results of his experiments were most satisfactory and of practical interest. he began by submitting different seeds to the action of an electric current, and found that their development was rendered more rapid and complete. he experimented with the seeds of haricot beans, sunflowers, winter and spring rye. two lots, of twelve groups of one hundred and twenty seeds each, were plunged into water until they swelled, and while wet the seeds were introduced into long glass cylinders, open at both ends. copper disks were pressed against the seeds, the disks were connected with the poles of an induction coil, the current was kept on for one or two minutes and immediately afterward the seeds were sown. the temperature was kept from ° to ° fahrenheit, and the experiments repeated four times. the following table shows the results: peas. beans. barley. sunflowers. days. days. days. days. electrified seeds developed in . . non-electrified seeds developed in it was also observed that the plants coming from electrified seeds were better developed, their leaves were much larger and their color brighter than in those plants growing from non-electrified seeds. the current did not affect the yield. at the botanical gardens at kew, the following experiment was tried: large plates of zinc and copper ( . meter and . meter) were placed in the soil and connected by wires, so arranged that the current passed through the ground; the arrangement was really a battery of (zinc | earth | copper). this method was applied to pot herbs and flowering plants and also to the growing of garden produce; in the latter case the result was a large crop and the vegetables grown were of enormous size. extensive experiments in electroculture were also made at pskov, russia. plots of earth were sown to rye, corn, oats, barley, peas, clover and flax; around these respective plots were placed insulating rods, on the top of which were crown-shaped collectors--the latter connected by means of wires. atmospheric electricity was thus collected above the seeds, and the latter matured in a highly electrified atmosphere; the plots were submitted to identical conditions and the experiments were carried on for five years. the results showed a considerable increase in the yield of seed and straw, the ripening was more rapid and the barley ripened nearly two weeks earlier with electroculture. potatoes grown by the latter method were seldom diseased, only to per cent., against to per cent. by ordinary culture. grandeau, at the school of forestry at nancy, found by experiment that the electrical tension always existing between the upper air and soil stimulated growth. he found plants protected from the influence were less vigorous than those subject to it. macagno, also believing that the passage of electricity from air through the vine to earth would stimulate growth, selected a certain number of vines, all of the same variety and all in the same condition of health and development. sixteen vines were submitted to experiment and sixteen were left to natural influences. in the ends of the vines under treatment, pointed platinum wires were inserted, to which were attached copper wires, leading to the tops of tall poles near the vines; at the base of these same vines other platinum wires were inserted and connected by copper wires with the soil. at the close of the experiment, which began april , and lasted till september , the wood, leaves and fruit of both sets of vines were submitted to careful analysis with the following results: without conductor. with conductor. moisture per cent. . . sugar. . . tartaric acid. . . bitartrate of potash. . . thus we see that the percentage of moisture and sugar is greater and the undesirable acid lower in those vines subject to electrical influences than in those left to natural conditions. there are also experiments which prove the beneficial effects of electricity on vines attacked by phylloxera. the following experiments were made at this station: several plots were prepared in the greenhouse, all of which had the same kind of soil and were subjected to like influences and conditions. frames in the form of a parallelogram, about three feet by two feet, were put together; across the narrow way were run copper wires in series of from four to nine strands, each series separated by a space about four inches wide, and the strands by a space of one-half inch. these frames were buried in the soil of the plot at a little depth, so that the roots of the garden plants set would come in contact with the wires, the supposition being that the currents of electricity passing along the wires would decompose into its constituents the plant food in the vicinity of the roots and more readily prepare it for the plants. two electric gardens were thus prepared and each furnished with two common battery cells, so arranged as to allow continuous currents to pass through each series of wires. near each electric garden was a plot prepared in the same manner, save the electrical apparatus. we will call the two gardens a and b. the place chosen for the experiments was in a part of the greenhouse which is given up largely to the raising of lettuce, and the gardens were located where much trouble from mildew had been experienced. the reason for this choice of location was to notice, if any, the effect of electricity upon mildew, this disease being, as it is well known, a source of much trouble to those who desire to grow early lettuce. the soil was carefully prepared, the material taken from a pile of loam commonly used in the plant house. garden a was located where mildew had been the most detrimental; the experiments began the first of january and closed the first of april. for the garden, fifteen lettuce plants of the head variety were selected, all of the same size and of the same degree of vitality, as nearly as could be determined; the plants were set directly over the wires, so that the roots were in contact with the latter; the plants were well watered and cared for as in ordinary culture, and the fluid in the battery cells was renewed from time to time, that the current of electricity might not become too feeble. at the close of the experiments the following results were noted: five plants died from mildew, the others were well developed and the heads large. the largest heads were over the greatest number of wires and nearest the electrodes. it was further noticed that the healthiest and largest plants, as soon as the current became feeble or ceased altogether, began to be affected with mildew. on examining the roots of the plants it was found that they had grown about the wires as if there they found the greatest amount of nourishment; the roots were healthy and in no way appeared to have been injured by the current, but, rather, much benefited by the electrical influences. beside garden a was prepared another plot of the same dimensions, having the same kind of soil and treated in like manner as the first, but the electrical apparatus and wires were wanting. at the close of the experiments only three plants had partially developed, and two of these were nearly destroyed by mildew--one only was free from the disease. the results, therefore, show that the healthiest and largest plants grew in the electric plot. in the second experiment, which we called b, twenty plants of the same variety of lettuce and of equal size were taken. the treatment given was the same as the plants in plot a received. five plants only remained unaffected with mildew; seven died from the disease when they were half grown; the rest were quite well developed, but at the last part of the experiment began to be affected. several heads were large, the largest being over the greatest number of wires and nearest the electrodes. examination of the roots disclosed the same phenomena as in a. near plot b were also set twenty other plants, subjected to like conditions as the first, but without electricity; all but one died from mildew before they were half grown, the solitary plant that survived being only partly developed at the close of the experiment, and even this was badly affected with the disease. everything considered, the results were in favor of electricity. those plants subjected to the greatest electrical influence were hardier, healthier, larger, had a better color, and were much less affected by mildew than the others. experiments were made with various grasses, but no marked results were obtained. the question would naturally arise whether there may not be a limit reached where electricity would completely overcome the attack of mildew and stimulate the plant to a healthy and vigorous condition throughout its entire growth. from the fact that the hardiest, healthiest, and largest heads of lettuce grew over the greatest number of currents and nearest the electrodes, it would seem that electricity is one of the agents employed by nature to aid in supplying the plant with nourishment and to stimulate its growth. to what extent plants may be submitted to electrical influence, or what strength of current is best suited to them and what currents prove detrimental to their development, have not been determined as yet, but it is desirable to continue this research until some definite information shall be gained on these points. probably different varieties of plants differ greatly in their capacity for enduring the action of electric currents without injury--experiment alone must determine this. it has been proved that the slow discharge of static electricity facilitates the assimilation of nitrogen by plants. faraday showed that plants grown in metallic cages, around which circulated electric currents, contained per cent. less organic matter than plants grown in the open air. it would seem from the researches of the latter physicist that those plants requiring a large percentage of nitrogen for their development would be remarkably benefited if grown under electric influence.--_massachusetts agricultural college, bulletin no ._ [a very interesting article on the influence of electricity upon plants, illustrated, is given in supplement . it presents the results of the studies of prof. lemstrom, of helsingfors.] * * * * * the treatment of rattlesnake bite by permanganate of potassium, based on nine successful cases. by amos w. barber, m.d.,[ ] cheyenne. [footnote : governor of wyoming.] poisoned wounds, inflicted by the fangs of the rattlesnake, are happily more rare each year, since, as the country is becoming more populated, the crotalus is rapidly being exterminated. yet, considering the recklessness which characterizes the cow boy in his treatment of this reptile, it is astonishing that this class of injury is not more common. thus it is the invariable custom among the cattlemen to dismount and destroy these snakes whenever they are seen. this is readily accomplished, since a slight blow will break the back. this blow is, however, generally delivered by means of the quirt, a whip not over two and a half feet long, and hence a weapon which brings the one who wields it in unpleasant proximity to the fangs of the reptile. a still more dangerous practice, and one which i have frequently seen, is a method of playing with the rattlesnake for the delectation of the cow boy at the expense of a "tenderfoot." it is well known that unless a snake is coiled, or held by the tail or body, or placed at length in a hole or crevice so narrow that by rendering its length sinuous a certain amount of support is given, it cannot strike. on this theory a mounted cow boy first puts a rattler to flight, then pushes his pony in pursuit, stoops from the saddle, seizes it by the tail, gives a quick upward jerk, and, swinging it so rapidly around his head that it is impossible for it to strike, sets off in pursuit of whoever has exhibited most terror at the sight of the reptile. when within fair distance he hurls the snake at the unfortunate victim, in the full assurance that even should it strike him it cannot bury its fangs in his flesh, since it is impossible for it to coil till it reaches the ground. this is a jest of which i have frequently been the victim, nor have i yet learned to appreciate it with unalloyed mirth. the belief that rattlesnakes always give warning before striking is not well founded. if come upon suddenly, they often strike first, and if disturbed when in a space so narrow that the coil cannot be formed, they may give no warning of their presence beyond the penetration of the fangs into the hand or foot of an intruder. one such case i saw. it seems to be well established that a snake will not voluntarily crawl over a hair rope, and in certain parts of the country it is common for campers-out to surround their beds with such a rope, since the reptiles seek warmth, and are frequently found under or in the blankets of those sleeping on the ground. after an exceptionally large experience with wounds inflicted by the fangs of the rattlesnake, and an experience which, i am glad to say, has been most successful in its outcome, i think it my duty to add, from a practical standpoint, my testimony as to the efficacy of permanganate of potassium in the treatment of this class of cases. this drug was first introduced by lacerda, of brazil, and, if more generally used, would, i believe, render comparatively innocuous a class of injury which now usually terminates in death. i make this statement as to the fatality of crotalus poison advisedly. i know the belief is very common that the poison of a rattlesnake is readily combated by full doses of whisky. this is fallacious. i have taken the pains to investigate a number of instances of cure resulting from the employment of free stimulation. in each case the fangs did not penetrate deeply into the tissues, but either scratched over the surface or tore through, making a wound of entrance and exit, so that the poison, or at least the major part of it, was not injected into the tissues of the person struck. the effect is very much the same as when an inexperienced practitioner picks up a fold of skin for the purpose of making a hypodermic injection, and plunges his needle entirely through, forcing the medicament wide of his patient. nearly all, if not all, of the cases treated by stimulation alone have, according to my experience, perished if they have received a full dose of virus from a vigorous snake. one of these cases lived for upward of a month. he then perished of what might be considered a chronic pyæmia, the symptoms being those of blood poisoning, accompanied by multiple abscesses. another case, not occurring in my own practice, died at the end of four days apparently of cardiac failure. active delirium persisted all through this case. two other cases treated by stimulants also died with symptoms of more or less acute blood poisoning. the feeling is almost universal among the people of wyoming that a fair strike from a rattlesnake is certain death, and that the free use of stimulants simply postpones the end. i do not for a moment deny that a strong, lusty man may be struck fairly by a rattlesnake and if the wound is at once opened and cauterized, and the heart judiciously supported, he may yet recover; still the fact remains that the great majority of these cases perish at a longer or shorter interval following the infliction of the wound. hence any treatment that will save even the majority of such cases is a distinct gain, and one which has saved every one of nine cases to which it has been applied needs no further commendation. the first case of rattlesnake wound to which i was called occurred in . a cow boy was bitten on the foot, the fang penetrating through the boot. he was brought forty miles to fort fetterman, where i was then stationed. i saw him about twenty-four hours after he was struck. there was an enormous swelling, extending up to the knee. the whole limb was bronzed in appearance. there was no special discoloration about the wound; in fact, the swelling disguised this to such an extent that it was impossible to determine exactly where the fangs had entered. the pulse was scarcely perceptible at the wrist; the heart was beating with excessive rapidity. the patient was suffering great pain. his mind was clear, but he was oppressed with a dreadful anxiety. up to the time i saw him he had received absolutely no treatment, excepting the application of a cactus poultice to the leg, since there was no whisky at the ranch where he was wounded. i at once made free incisions, five or six in number, from one to two inches in depth, and about three inches in length. these cuts gave him very little pain, nor was there much bleeding, though there was an enormous amount of serous oozing. into these wounds was poured a fifteen per cent. solution of permanganate of potassium, and fully half an hour was devoted to kneading this drug into the tissues. in addition i made many hypodermic injections into all portions of the swollen tissue, but particularly about the wound. since there was no very distinct line of demarkation between the swollen and healthy tissue, i did not, as in other cases, endeavor to prevent the extension of the cellular involvement by a complete circle of hypodermic injections. i employed, in all, about forty grains of the permanganate. in addition to the local treatment i pushed stimulation, employing carbonate of ammonium and whisky. by means of diuretics and laxatives the kidneys and bowels were encouraged to eliminate as much of the poison as possible. the patient went on to uninterrupted recovery. the wound healed with very little sloughing. the patient returned to his work in about a month. the cure of this case was regarded by the cow boys as most exceptional, since, in their experience, similar cases, even though very freely stimulated, had not recovered. some time later i was called to see a girl, aged , who was struck by a rattlesnake, fifty-six miles from fort fetterman. there was some trouble about procuring relays, and i was compelled to ride the same horse all the way out. this took a little short of five hours. this, together with the time consumed in sending me word, caused an interval of about twenty hours between the infliction of the injury and the time i saw the patient. i found the fangs had entered on either side of the distal joint of the middle metacarpal bone. the arm was enormously swollen, almost to the axilla, and exhibited a bronzed discoloration; this was especially marked about the wound and along the course of the lymphatics. the swollen area was _boggy_ to the touch, and exhibited a distinct line of demarkation between the healthy and diseased tissues, excepting along the course of the brachial vessels, where the indurated discolored area extended as a broad band into the axilliary lymphatics, which were distinctly swollen. the patient was delirious, was harrassed by terror, complained bitterly of pain, and had an exceedingly feeble, rapid heart action. there was marked dyspnoea, and all the signs of impending dissolution. i at once made free multiple incisions into all parts of the inflamed tissue, carrying two of my cuts through the wounds made by the fangs of the snake. in the arm these incisions were several inches long and from one to two inches deep. as in the former case, the bleeding was slight, but there was a free exudation of serum. into these wounds a fifteen per cent. permanganate of potassium solution was poured, and as much as possible was kneaded into the tissues. in addition multiple hypodermic injections were made, these being carried particularly into the bitten region, and circularly around the arm just at the border of the line of demarkation, thus endeavoring to limit by a complete circle of the antiseptic solution the further extension of the inflammatory process. in the region of the brachial vessels i hesitated to make my injections as thoroughly as in the rest of the circumference of the arm, fearing lest the permanganate of potassium might injure important vessels or nerves. this treatment caused very little pain, but immediately after the constitutional symptoms became distinctly aggravated. i stimulated freely, and at once made preparations to take the patient to the fort fetterman hospital. she was transported over the fifty-six miles, i riding the same horse back again, and arriving at fort fetterman the same evening. the after treatment of this case was comparatively simple. she was stimulated freely as long as cardiac weakness was manifested. as in the former case, diuretics and laxatives were employed. the arm was wrapped in cloth soaked in a weak permanganate solution, was placed in a splint, and was loosely bandaged. there was some sloughing, but this was treated on general surgical principles. the patient recovered the entire use of her arm, and was turned out cured in about six weeks. the third case i saw about fourteen hours after he was struck. the patient was a healthy blacksmith, about years of age. the wound was at about the middle of the forearm, the fangs entering toward the ulnar side. when i saw the patient he exhibited comparatively trifling symptoms. his heart action was rapid, and he was suffering from the typical despondency and terror, but i could not note the profound systemic depression characteristic of the great majority of cases. surrounding the wound and extending up the forearm for several inches there was a boggy swelling, exhibiting a sharp line of demarkation. it was bronzed in color, and was apparently spreading. i at once applied the intermittent ligature just above the elbow, and injected the permanganate of potassium solution freely all through the involved tissues, particularly in the region of the bite and about the periphery of the swelling, surrounding the latter by a complete ring of injections. the general treatment of this patient was continued on the same general line as described in the former cases, stimulants being employed moderately. he recovered without any bad symptoms. there was no sloughing; the swelling disappeared without any necrosis of tissue. he is still pursuing his trade in cheyenne, and suffers from absolutely no disability. i saw but one case shortly after the wound was inflicted. this patient was a healthy young man, who was struck about the middle of the dorsal surface of the hand, the fangs entering on each side of a metacarpal bone, and the poison lodging apparently in the palm of the hand. the patient, when seen, exhibited the characteristic terror and depression, weak, rapid heart action, and agonizing local pain. i made two small incisions in the region of the wound upon the dorsum of the hand, and injected permanganate of potassium freely. this patient ultimately recovered, but only after sloughing and prolonged suppuration. i believe that had i incised freely and at once from the palmar surface, i would have been spared this unpleasant complication. i have had in all nine cases, and without a single death. the others are in their general features and in the treatment employed quite similar to those given. the symptoms resulting from snake bite poison are strikingly like those dependent upon the violent septic poison seen in pre-antiseptic times. there is often the same prodromal chill, the high elevation of temperature, the profound effect on the circulation, and the rapid cellular involvement. the tissue disturbance following snake poisoning differs from ordinary cellulitis, however, in the following particulars: the color is _bronze_, not red; the involved area is _boggy_, not brawny; and the extension of the process is _exceedingly rapid_. the treatment applicable to one condition seems to be equally successful when applied to the other. in cellulitis, free incisions, antiseptic lotions, and active stimulation are the three means upon which the surgeon mainly depends, and in combating the local and general symptoms excited by snake bite poisoning, the same treatment has given me the successful results detailed above. whether or not permanganate of potassium is more active than other antiseptics in snake bite poisoning i am not prepared to state, but the high authority of s. weir mitchell, together with my own experience, does not incline me to substitute any other drug at present. i would formulate the treatment for poison of the rattlesnake as follows: . free incisions to the bottom of the wound and immediate cauterization; or, if this is not practicable, sucking of the wound. . the immediate application of an intermittent tourniquet, that is, one which is relaxed for a moment at a time, so that the poison may gain admission into the circulation in small doses. . the free administration of alcohol or carbonate of ammonium. this might be termed the _urgency treatment_ of snake bite poisoning. the _curative treatment_ requires-- . free incisions into all portions of the inflamed tissues, and the thorough kneading into these incisions of a fifteen per cent. solution of permanganate of potassium. . multiple injections of the same solution into all the inflamed regions, but particularly into the region of the wound. . the complete surrounding of all the involved tissues, by permanganate of potassium injections placed from half an inch to an inch apart, the needle being driven into the healthy tissue just beyond the line of demarkation, and its point being carried to the deepest part of the border of the indurated area. . the permanganate of potassium solution should be used freely in fifteen per cent. solution. i have used one and a half drachms of the pure drug diluted, and would not hesitate to use four times that quantity were it necessary, since it seems to exert no deleterious effect, either locally or generally. . the involved area should be dressed by means of lint saturated with fifteen per cent. permanganate of potassium solution. stimulants should be given according to the indications--i.e., the condition of the pulse. laxatives, diuretics, and diaphoretics should be administered to aid in the elimination of the poison. the diet should be as nutritious as the stomach can digest.--_the therapeutic gazette_. * * * * * chinese competitive examinations. wuchang, on the yangtsze opposite hankow, is the capital of the two provinces hupeh and hunan. here, every third year, the examination for competitors from both provinces is held, and a correspondent of the _north china herald_, of shanghai, describes the scene at the examination at the beginning of september last. the streets, he says, are thronged with long-robed, large-spectacled gentlemen, who inform the world at large by every fold of drapery, every swagger of gait, every curve of nail, that they are the aristocracy of the most ancient empire of the world. wuchang had from , to , bachelors of arts within its walls, who came from the far borders of the province for the examination for the provincial degree. about one-half per cent. will be successful; thousands of them know they have not the shadow of a chance, but literary etiquette binds them to appear. in the wake of these confucian scholars come a rout of traders, painters, scroll sellers, teapot venders, candle merchants, spectacle mongers, etc.; servants and friends swell the number, so that the examination makes a difference of some , or , to the resident population. in the great examination hall, which is composed of a series of pens shut off from each other in little rows of or , and the view of which is suggestive of a huge cattle market, there is accommodation for over , candidates. the observance of rules of academic propriety is very strict. a candidate may be excluded, not only for incompetence, but for writing his name in the wrong place, for tearing or blotting his examination paper, etc. after the examination of each batch a list of those allowed to compete for honors is published, and the essay forms for each district are prepared with proper names and particulars. the ancestors of the candidate for three generations must be recorded, they must be free from taint of _yamen_ service, prostitution, the barber's trade and the theater, or the candidate would not have obtained his first degree. with the forms cash (about s.) are presented to each candidate for food during the ordeal. the lists being thus prepared, on the sixth day of the eighth moon (tuesday, the th of september, in ), the city takes a holiday to witness the ceremony of "entering the curtain," i.e., opening the examination hall. for days coolies have been pumping water into great tanks, droves of pigs have been driven into the inclosure, doctors, tailors, cooks, coffins, printers, etc., have been massed within the hall for possible needs. the imperial commissioners are escorted by the examination officials to the place. a dozen district magistrates have been appointed to superintend within the walls, and as many more outside, two prefects have office inside, and the governor of the province has also to be locked up during the eight days of examination. the whole company is first entertained to breakfast at the _yamen_, and then the procession forms; the ordinary umbrellas, lictors, gongs, feathers, and ragamuffins are there in force; the examiners and the highest officers are carried in open chairs draped in scarlet and covered with tiger skins. the dead silence that falls on the crowd betokens the approach of the governor, who brings up the rear. then the bustle of the actual examination begins. the hall is a miniature city. practically martial law is proclaimed. in the central tower is a sword, and misdemeanor within the limits is punished with instant death. the mandarins take up their quarters in their respective lodges, the whole army of writers whose duty it is to copy out the essays of the candidates, to prevent collusion, take their places. altogether there must be over , people shut in. cases have been known in which a hopeful candidate was crushed to death in the crowd at the gate. each candidate is first identified, and he is assigned a certain number which corresponds to a cell a few feet square, containing one board for a seat and one for a desk. meanwhile the printers in the building are hard at work printing the essay texts. each row of cells has two attendants for cooking, etc., assigned to it, the candidates take their seats, the rows are locked from the outside, the themes are handed out, the contest has begun. the examination is divided into three bouts of about hours, two nights and a day, each, with intervals of a day. the first is the production of three essays on the four assigned books; the second of five essays on the five classics; the third of five essays on miscellaneous subjects. the strain, as may be imagined, is very great, and several victims die in the hall. the literary ambition which leads old men of and to enter not unfrequently destroys them. should any fatal case occur, the coffin may on no account be carried out through the gates; it must be lifted over or sometimes through a breach in the wall. death must not pollute the great entrance. at the end of the third trial, the first batch of those who have completed their essays is honored with the firing of guns, the bows of the officials, and the ministry of a band of music. three weeks of anxious waiting will ensue before a huge crowd will assemble to see the list published. then the successful candidates are the pride of their country side, and well do the survivors of such an ordeal deserve their credit. the case of those who are in the last selection and are left degreeless, for the stern reason that some must be crowded out, is the hardest of all. * * * * * high speed engine and dynamo. we illustrate a high speed engine and dynamo constructed by easton & anderson, london. this plant was used at the royal agricultural society's show at doncaster in testing the machinery in the dairy, and constituted a distinct innovation, as well as an improvement, on the appliances previously employed for the purpose. the separator, or whatever might be the machine under trial, was driven by an electric motor fed by a current from the dynamo we illustrate. a record was made of the volts and amperes used, and from this the power expended was deduced, the motor having been previously carefully calibrated by means of a brake. so delicate was the test that the observers could detect the presence of a warm bearing in the separator from the change in the readings of the ammeter. [illustration: improved high speed engine and dynamo.] the engine is carefully balanced to enable it to run at the very high speed of revolutions per minute. the cranks are opposite each other, and the moving parts connected with the two pistons are of the same weight. the result is complete absence of vibration, and exceedingly quiet running. very liberal lubricating arrangements are fitted to provide for long runs, while uniformity of speed is provided for by a pickering governor. the high pressure cylinder is in. in diameter, and the low pressure cylinder is in. in diameter. the stroke in each case is in. [illustration: fig. .] the dynamo is designed to feed sixty lamps of candle power each, the current being amperes at volts. the armature is of the drum type. the peculiar feature of it is that grooves are planed in the laminated core from end to end, and in these grooves the conductors, which are of ribbon section, are laid. slips of insulating material are laid between the coils and the dovetailed mouths of the grooves are closed with bone or vulcanized fiber, or other dielectric. at each end of the core there are fitted non-magnetic covers. at the commutator end the cover is like a truncated cone, and incloses the connections completely. one end of the cone is supported on the end plate of the armature and the other end on a ring on the commutator. a bell-shaped cover incloses the conductors at the other end of the armature. the result is that the conductors are completely incased, protected from all mechanical injury, and positively driven. they can neither be displaced nor abraded. the conductors on the magnet coils are likewise carefully protected from harm by metal coverings. these dynamos are made in sixteen sizes, of which seven sizes are designed to feed more than lamps, the largest serving for lamps. [illustration: fig. .] messrs. easton & anderson are showing machinery of this type at the crystal palace electrical exhibition now open in london.--_engineering_. * * * * * chlorine gas and soda by the electrolytic process. the decomposition of a solution of common salt, and its conversion into chlorine gas and caustic soda solution by means of an electric current, has long been a study with electro-chemists. experimentally it has often been effected, but so far as we are aware, the success of this method of production has never until now been demonstrated on a sound commercial basis. the solution of this important industrial problem is due to mr. james greenwood, who has been engaged in the development of electro-chemical processes for many years. the outcome of this is that mr. greenwood has now perfected an electrolytic process for the direct production of caustic soda and chlorine, as well as other chemical products, the operation of which we recently inspected at phoenix wharf, battersea, london. one of the special features in connection with mr. greenwood's new departure is the novel and ingenious method by which the electrolyzed products are separated, and their recombination rendered impossible. this object is attained by the use of a specially constructed diaphragm which is composed of a series of v-shaped glass troughs, fitted in a frame within each other with a small space between them, which is lightly packed with asbestos fiber. another important feature of the apparatus is a compound anode which consists of carbon plates, with a metal core to increase the conductivity. the anode is treated in a special manner so as to render it non-porous and impervious to attack by the nascent chlorine evolved on its surface. no anode appears ever to have been invented that is at all suitable for working on a large scale, and the successful introduction of this compound anode, therefore, constitutes a marked advance in the apparatus used in electrolytic methods of production. the apparatus by which the new process is being successfully demonstrated on a working scale has been put up by the caustic soda and chlorine syndicate, london, and has been in operation for several months past. the installation consists of five large electrolytic vessels, each of which is fitted up with five anodes and six cathodes arranged alternately. the anodes and cathodes are separated by the special diaphragms, and each vessel is thus divided into ten anode or chlorine sections and ten cathode or caustic soda sections. the anodes and cathodes in each vessel are connected up in parallel similar to an ordinary storage battery, but the five electrolytic vessels are connected up in series. the current is produced by an elwell-parker dynamo, and the electromotive force required to overcome the resistance of each vessel is about . volts, with a current density of amperes per square foot of electrode surface. the anode sections, numbering fifty altogether, are connected by means of tubes, the inlet being at the bottom and the outlet at the top of each section. the whole of the cathode sections are connected in the same manner. in commencing operations, the electrolytic vessels are charged with a solution of common salt, through which a current of electricity is then passed, thus decomposing or splitting up the salt into its elements, chlorine and sodium. in the separation of the sodium, however, a secondary action takes place, which converts it into caustic soda. an automatic circulation of the solutions is maintained by placing the charging tanks at a slight elevation, and the vessels themselves on platforms arranged in steps. the solutions are pumped back from the lowest vessel to their respective charging tanks, the salt solution to be further decomposed and the caustic soda solution to be further concentrated. the chlorine gas evolved in the fifty anode sections is conveyed by means of main and branch tubes into several absorbers, in which milk of lime, kept in a state of agitation, takes up the chlorine, thus making it into bleaching or chlorate liquor as may be required. if the chlorine is required to be made into bleaching powder, then it is conveyed into leaden chambers and treated with lime in the usual manner. the caustic soda formed in the fifty cathode sections is more or less concentrated according to the particular purpose for which it may be required. if, however, the caustic soda is required in solid form, and practically free from salt, then the caustic alkaline liquor is transferred from the electrolytic vessels to evaporating pans, where it is concentrated to the required strength by evaporation and at the same time the salt remaining in the solution is eliminated by precipitation. such is the method of manufacturing caustic soda and chlorine by this process, which will doubtless have a most important bearing upon many trades and manufactures, more particularly upon the paper, soap, and bleaching industries. but the invention does not stop where we have left it, for it is stated that the process can be applied to the production of sodium amalgam and chlorine for extracting gold and other metals from their ores. it can also be utilized in the production of caustic and chlorate of potash and other chemicals, which can be manufactured in a state of the greatest purity. a very important consideration is that of cost, for upon this depends commercial success. it is therefore satisfactory to learn that the cost of production has been determined by the most careful electrical and analytical tests, which demonstrate an economy of over per cent. as compared with present methods. highly favorable reports on the process have been made by dr. g. gore, f.r.s., the eminent authority on electro-chemical processes, by mr. w.h. preece, f.r.s., and by messrs. cross & bevan, consulting chemists. dr. gore states that the chemical and electrical principles upon which this process is based are thoroughly sound, and that the process is of a scientifically practical character. should, however, the economy of production even fall somewhat below the anticipations of those who have examined into the process very carefully, it can hardly fail to prove as successful commercially as it has scientifically. * * * * * completion of the mersey tunnel railway. on the th of january (says the _liverpool daily post_) will be opened for traffic the new station of the mersey tunnel railway at the bottom of bold street. with the completion of the station at bold street the scheme may be said to have been brought successfully to a conclusion. it was not until , after the expenditure of , _l._ upon trial borings, that the promoters ventured to appeal to the public for support, and that a company, of which the right hon. h. cecil raikes, m.p., was chairman, was formed for carrying the project of the mersey railway into effect. the experience of the engineers in the construction of the tunnel is not a little curious. it was proved by the borings that the position in which the tunnel was proposed to be bored was not only the most important from the point of view of public convenience, and therefore of commercial advantage, but was from the point of view of engineering difficulty decidedly the most preferable. in this position the cuttings passed through the sandstone rock, although on the liverpool side the shafts were sunk through a considerable depth through "made" ground, the whole of mann island and the goree being composed of earth and gravel tipped on the old bank of the river. indeed the miners passed through the cellars of old houses and unearthed old water pipes; excavated through a depth of tipped rubbish on which these houses had evidently been built; and then came upon the former strand of the river, beneath which was the blue silt usually found; then a stratum of bowlder clay; and finally the red sandstone rock. once begun, the works were pushed forward night and day, sundays excepted, until january, , when the last few feet of rock were cleared away by the boring machine, and the mayors of liverpool and birkenhead met in fraternal greeting beneath the river. the operations gave employment to , men working three shifts of eight hours each, but were greatly accelerated by the use of colonel beaumont's boring machine, on which disks of chilled iron are set in a strong iron bar made to revolve by means of compressed air. this machine scooped out a tunnel feet in diameter; and by successive improvements colonel beaumont attained a speed of feet per week, leaving the old method of blasting far behind. as the machine moved forward the rock behind was broken out to the size of the main tunnel and bricked in in short lengths. one remarkable circumstance in connection with the work is that the boring from the birkenhead side and the boring from liverpool were found, when they were completed and joined, to be out of line by only inch. this excellent result was attained by careful calculations and experiments with perpendicular wires kept in position by weights, which, to avoid oscillation, were suspended in buckets of water. from shaft to shaft the tunnel is , yards in length and feet in diameter; but for a length of feet at the james street and hamilton square stations the arch is enlarged to ½ feet. the tunnel is lined with from six to eight rings of solid brickwork embedded in cement, the two inner rings being blue staffordshire or burnley bricks. for the purpose of ventilation a smaller tunnel, feet in diameter, was bored parallel with the main tunnel, with which it is connected in eight places by cross cuts, provided with suitable doors. both at liverpool and at birkenhead there are two guibal fans, one feet and the other feet in diameter. the smaller, which throw each , cubic feet of air per minute, ventilate the continuations of the tunnel under liverpool and birkenhead respectively, and the larger tunnel under the river. the fans remove together , cubic feet of air per minute, and by this combined operation the entire air in the tunnel is changed once in every seven minutes. by the use of regulating shutters the air passes in a continuous current and the fans are noiseless. the telegraph and telephone wires pass through the tunnel, thus avoiding the long detour by runcorn. probably, as a feat of engineering, the construction of the new station at bold street is not inferior to any part of the scheme advanced. under very singular and perplexing difficulties it could only be proceeded with in its first stages from midnight until six o'clock the following morning, it being of course essential that the traffic at the central station should not be interfered with. during these hours, night after night, trenches were cut at intervals of feet across the roadway connecting the arrival platforms at the station, and into these were placed strong balks of timber, across which planks were laid as a temporary roadway. beneath these planks, which were taken up and put down as required, the rock was excavated to a depth of feet, and the balks supported upon stout props. then from the driftway or rough boring beneath well holes were bored to the upper excavation, and through them the strong upright iron pillars designed to support the roof of the new tunnel station were passed, bedded and securely fixed in position. no sooner were they _in situ_ than the most troublesome part of the task was entered upon, for the balks had then to be removed in order to allow to be placed in position the girders running the length of the new station, and resting on the tops of the upright pillars. from these longitudinal girders cross girders of great strength were placed, and between these were built brick arches, packed above with concrete. this formed the roof of the new station. one portion of it passed under the rails in the station above, and had to be constructed without stoppage of the traffic. the rails had consequently to be supported on a temporary steel bridge of ingenious design, constructed by mr. c.a. rowlendson, the resident engineer and manager of the company, under whose personal supervision, as representing sir douglas fox, the work has been carried out. with this device the men were enabled to go on in safety although locomotives were passing immediately above their heads. after the completion of the roof the station below was excavated by what is technically called "plug and feather" work--that is to say, by drilling holes into which powerful wedges are driven to split the rock. * * * * * a steam street railway motor. [illustration: north chicago street railroad engine] while in paris, president yerkes, of the north chicago street railway company, purchased a noiseless steam motor, the results in experimenting with which will be watched with great interest. the accompanying engraving, for which we are indebted to the _street railway review_, gives a very accurate idea of the general external appearance. the car is all steel throughout, except windows, doors and ceiling. it is ft. long, ft. wide, and ft. high, and weighs about seven tons. the engines, which have horse power and are of the double cylinder pattern, are below the floor and connected directly to the wheels. the wheels are four in number and in. in diameter. the internal appearance and general arrangement of machinery, etc., is about that of the ordinary steam dummy. it will run in either direction, and the exhaust steam is run through a series of mufflers which suppress the sound, condense the steam and return the water to the boiler, which occupies the center of the car. the motor was built in ghent, belgium, and cost about $ , , custom house duties amounting to about $ , more.--_the railway review_. * * * * * twenty-four knot steamers. probably the most important form of steam machinery is the marine engine, not only because of the conditions under which it works, but because of the great power it is called upon to exert. naturally its most interesting application is to atlantic steaming. the success of the four great liners, teutonic, majestic, city of paris and city of new york, has stimulated demand, and the cunard company has resolved to add to its fleet, and place two ships on the atlantic which will outstrip the racers we have named. the visitor to the late naval exhibition interested in shipping will have remarked at each of the several exhibits of the great firms a model of a projected steamer, intended to reduce the present record of the six days' voyage across the atlantic--the _ne plus ultra_ at this time of steam navigation. to secure this present result a continuous steaming for the six days at knot speed is requisite, not to mention an extra day or two at each end of the voyage. the city of paris and the city of new york, furst bismarck, teutonic and majestic are capable of this, with the umbria and etruria close behind at to knots. only ten years ago the average passage, reckoned in the same way as from land to land--or queenstown to sandy hook--was seven days with a speed of knots, the performance of such vessels as the arizona and alaska. twenty years ago the length of the voyage was estimated as seven and a half to eight days at a speed of knots, the performance of such vessels as the germanic and britannic of the white star fleet of , tons and , horse power. thirty years ago the paddle steamer was not yet driven off the ocean, and we find the scotia crossing in between eight and nine days, at a speed of or knots. in ten and a half to twelve and a half days was allowed for the passage between liverpool and new york. so as we recede we finally arrive at the pioneer vessels, the sirius and great western, crossing in fourteen to eighteen days at a speed of to knots. for these historical details an interesting paper may be consulted, "de toenemende grootte der zee-stoombooten," , by professor a. huet, of the delft polytechnic school. each of the last two or three decades has thus succeeded, always, however, with increasing difficulty, in knocking off a day from the duration of the voyage. but although the present six-day knot boats are of extreme size and power, and date only from the last two or three years, still the world of travelers declares itself unsatisfied. already we hear that another day must be struck off, and that five-day steamers have become a necessity of modern requirements, keeping up a continuous ocean speed of ½ knots to knots. shipbuilders and engineers are ashamed to mention the word _impossible_; and designers are already at work, as we saw in the naval exhibition, but only so far in the model stage; as the absence of any of the well known distinguishing blazons of the foremost lines was sufficient to show that no order had been placed for the construction of a real vessel. it will take a very short time to examine the task of the naval architect required to secure these onerous and magnificent conditions, five days' continuous ocean steaming at a speed of knots. the most practical, theory-despising among them must for the nonce become a theorist, and argue from the known to the unknown; and, first, the practical man will turn--secretly perhaps, but wisely--to the invaluable experiments and laws laid down so clearly by the late mr. froude. although primarily designed to assist the admiralty in arguing from the resistance of a model to that of the full size vessel, the practical man need not thereby despise froude's laws, as he is able to choose his mode: to any scale he likes, and he can take his experiments ready made by practice on a large scale, as newton took the phenomena of astronomy for the illustration of the mechanical laws. suppose then he takes the city of paris as his model, ft. by ft., in round numbers , tons displacement, and , horse power, for a speed of knots, with a coal capacity of , tons, sufficient, with contingencies, for a voyage of six to eight days. or we may take a later knot vessel, the furst bismarck, ft. by ft., , tons, and , horse power, speed knots, and coal capacity , tons, to allow for the entire length of voyage to germany. in froude's method of comparison the laws of mechanical similitude are preserved if we make the displacements of the model and of its copy in the ratio of the sixth power of the speeds designed, or the length as the square of the speed. our new knot vessel, taking the city of paris as a model, would therefore have , ( ÷ )^{ } = , , say , tons displacement, and would be ft. × ft. in dimensions. the horse power would have to be as the _seventh_ power of the speed, and our vessel would therefore have , ( ÷ )^{ }, or say , horse power. further applications of froude's laws of similitude will show that the steam pressure and piston speed would have to be raised per cent., while the revolutions were discounted per cent., supposing the engines and propellers to be increased in size to scale. to provide the requisite enormous boiler power, all geometrical scale would disappear; but it would carry us too far at present to follow up this interesting comparison. our naval architect is not likely at present to proceed further with this monstrous design, exceeding even the great eastern in size, if only because no dock is in existence capable of receiving such a ship. he has however learned something of value, namely, that this vessel, if the proper similitude is carried out, is capable of keeping up a speed of knots for five days with ample coal supply, provided the boilers are not found to occupy all the available space. for it is an immediate consequence of froude's laws that in similar vessels run at corresponding speeds over the same voyage, the coal capacity is proportionately the same, or that a ton of coal will carry the same number of tons of displacement over the same distance. thus our enlarged city of paris would require to carry about , tons of coal, burning tons a day. with the britannic and germanic as models of , tons and , horse power at knot speed, the knot vessel would require to be of , tons and , horse power, to carry sufficient coal for the voyage of , miles. these enormous vessels being out of the question, the designer must reduce the size. but now the city of paris will no longer serve as a model, he must look elsewhere for a vessel of high speed, and smaller scale, and naturally he picks out a torpedo boat at the other end of the scale. a speed of knots--and it is claimed even of , , and knots--has been attained on the mile by a torpedo boat. but such a performance is useless for our mode of comparison, as sufficient fuel at this high speed for ten or twelve hours only at most can be carried--a voyage of, say, miles; while our steamer is required to carry coal for , miles. the russian torpedo boat wiborg, for instance, is designed to carry coal for , miles at knot speed; but at knots this fuel would last only twenty-seven hours, carrying the vessel miles. it will now be found that with this limited coal capacity the speed of the ordinary torpedo boat must be reduced considerably below knots for it to be able to cross the atlantic, , miles under steam. so that, even at a possible speed of knots for the voyage, the full sized knot five-day vessel, of which the best torpedo boat is the model, must have ( . )^{ }, say times the tonnage, and ( . )^{ }, or times the horse power. the enlarged wiborg would thus not differ much from the enlarged city of paris. a better model to select would be one of the recent dispatch boats, commerce destroyers, or torpedo catchers, recently designed by mr. w.h. white, for our navy--the intrepid or endymion, for instance. the intrepid is ft. by ft., , tons, and , horse power for knot speed, with hours' coal capacity for , miles at knot speed; which will reduce to , miles at knots, and , miles at knots. the endymion is ft. by ft., with coal capacity for , miles at knot speed, or for about hours or six days. the enlarged endymion for the same voyage of , miles in five days, or at ½ knot speed, would be per cent larger and broader, that is ft. by ft., and of threefold tonnage, and three and a half times, or about , horse power--about the dimensions of the furst bismarck, but much more powerfully engined. this agrees fairly with the estimate in the scientific american of th sept, ., where it is stated that twenty-two boilers, at a working pressure of lb. on the square inch, would be required, allowing ½ lb. of coal per horse power hour. the intrepid, enlarged to a knot boat, for the same length of voyage of , miles, would be ft. by ft., , tons, and about , horse power. so now we are nearing the messrs. thomson design in the naval exhibition of the five-day steamer, ½ knot speed, ft. by ft., and , to , horse power. no one doubts the ability of our shipbuilding yards to turn out these monsters; and on the measured mile, and for a good long distance, we shall certainly see the contract speeds attained and some excelled. but the whole difficulty turns on the question of the coal capacity, and whether it is sufficient to last for even five days or for , miles. every effort then must be made to shorten the length of the voyage from port to port; and we may yet see galway and halifax, only , miles apart, once more mentioned as the starting points of the voyage as of old, in the earliest days of steam navigation. in those days the question of fuel supply was a difficulty, even at the then slow speeds, in consequence of the wasteful character of the engines, burning from lb. of coal and upward per horse power hour. dr. lardner's calculations, based upon the average performance of those days, justified him in saying that steam navigation could not pay--as was really the case until the introduction of the compound engine. it is recorded in admiral preble's "origin and development of steam navigation," philadelphia, , page , that the sirius, tons and horse power, on her return voyage had to burn up all that old be spared on board, and took seventeen days to reach falmouth. an interesting old book to consult now is atherton's "tables of steamship capacity," , based as they are upon the performance of the marine engine of the day. atherton calculates that a , ton vessel could at knots carry only tons of cargo , miles, while a , ton vessel at knots on a voyage of , miles could carry no cargo at all. also that the cost per ton of cargo at knots would be twenty times the cost at eight knots, implying a coal consumption reaching to lb. per horse power hour. it is quite possible that some invention is still latent which will enable us to go considerably below the present average consumption of lb. to ½ lb. per horse power hour; but at present our rate of progress appears asymptotic to a definite limit. to conclude, the whole difficulty is one of fuel supply, and it is useless to employ a fast torpedo boat as our model, except at the speed at which the torpedo boat can carry her own fuel to cross the atlantic. if the voyage must be reduced in time, let it be reduced from six days to four, by running between galway and halifax, a problem not too extravagant in its demands for modern engineering capabilities. a statement has recently gained a certain amount of circulation to the effect that the inman company was about to use petroleum as fuel, in order to obtain more steam. we have the best possible authority for saying there is not the least syllable of truth in this rumor. it has also been stated that since solid piston valves have been fitted to the teutonic in lieu of the original spring ring valves, she has steamed faster. this rumor is only partially true. her record, outward passage, of days hours minutes, was made on her previous voyage. she has, however, since made her three fastest trips homeward.--_the engineer_. * * * * * the military engineer and his work.[ ] by col. w.r. king. [footnote : a lecture delivered before the students of sibley college, cornell university, december , .--_the crank_.] it is not an easy matter to present a dry subject in such an attractive form as to excite a thrilling interest in it, and military science is no exception to this rule. an ingenious military instructor at one of our universities has succeeded in pointing out certain analogies between grand tactics and the festive game of football, which appears to have greatly improved the football, if we may judge from the recent victories of the blue over the red and the black and orange, but it is not so clear that the effect of the union has been very beneficial to military science; and even if such had been the case, i fear there are no similar analogies that would be useful in enlivening the subject of military engineering. from the earliest times of which we have record man has been disposed to strive with his fellow man, either to maintain his own rights or to possess himself of some rights or material advantage enjoyed by others. when one or only a few men encroach on the rights of others in an organized community, they may be restrained by the legal machinery of the state, such as courts, police, and prisons, but when a whole community or state rises against another, the civil law becomes powerless and a state of war ensues. it is not proposed here to discuss the ethics of this question, nor the desirability of providing a suitable court of nations for settling all international difficulties without war. the great advantage of such a system of avoiding war is admitted by all intelligent people. we notice here a singular inconsistency in the principles upon which this strife is carried on, viz.: if it be a single combat, either a friendly contest or a deadly one, the parties are expected to contest on equal terms as nearly as may be arranged; but if large numbers are engaged, or in other words, when the contest becomes war, the rule is reversed and each party is expected to take every possible advantage of his adversary, even to the extent of stratagem or deception. in fact, it has passed into a proverb that "all things are fair in love and war." now one of the first things resorted to, in order to gain an advantage over the enemy, was to bring in material appliances, such as walls, ditches, catapults, scaling ladders, battering rams, and subsequently the more modern appliances, such as guns, forts, and torpedoes, all of which are known as engines of war, and the men who built and operated these engines were very naturally called engineers. it is this kind of an artificer that shakespeare refers to when he playfully suggests that "'tis the sport to have the engineer hoist with his own petard." the early military engineer has left ample records and monuments of his genius. the walls of ancient cities, castles that still crown many hills in both hemispheres, the great chinese wall, the historical bridge of julius cæsar, which with charming simplicity he tells us was built because it did not comport with his dignity to cross the stream in boats, the bridge of boats across the hellespont, by xerxes, are all examples of early military engineering. the bible tells us "king uzziah built towers at the gates of jerusalem, and at the turning of the wall, and fortified them." we may note in passing that the buttresses, battlements, and bartizans with which our modern architects ornament or disfigure churches, peaceful dwellings, and public buildings, are copied from the early works of the military engineer. coming down to the military engineers of our own country, we find that one of the first acts of the continental congress, after appointing washington as commander-in-chief, was to authorize him to employ a number of engineers. it was not, however, until that a number of engineer officers from the french army arrived in this country, and were appointed in the continental army. general duportail was made chief engineer, and colonel kosciusko, the great polish patriot, was among his assistants. other officers of the continental army were employed on engineering duty; and under their supervision such works as the forts and the great chain barrier at west point were built, and the siege operations around boston and yorktown were carried on. after the close of the war, in , a corps of "artillerists and engineers" was organized. this corps was stationed at west point, and became the nucleus of the united states military academy. in , by operation of the law reorganizing the army, this corps was divided, as the names would indicate, into an artillery corps and corps of engineers. the corps of engineers consisted of one major, two captains, four lieutenants, and ten cadets. the artillery corps was again divided into the ordnance corps and several regiments of artillery, now five in number, while the duties of the corps of engineers were divided between the engineer corps and a corps of topographical engineers, organized at a later date; but on the breaking out of the late rebellion it was deemed best to unite the two corps, and they have so remained until the present time. the corps of engineers now consists of officers of various grades, from second lieutenant to brigadier general, of which last grade there is only one officer, the chief of the corps, and it requires something more than an average official lifetime for the aforesaid lieutenant to attain that rank. hardly one in ten of them ever reach it. daniel webster's remark to the young lawyer, that "there is always room at the top," will not apply to the corps of engineers. the officers are all graduates of the military academy, which institution continued as a part of the corps of engineers until . the vacancies in the corps are filled by the assignment to it of from two to six graduates each year, and there is attached to the corps a battalion of four companies of enlisted men, formerly called sappers and miners, but now known as the battalion of engineers. we now come naturally to the duties of our military engineer, and here i may remark that these duties are so varied and so numerous that a detailed recital of them would suggest goldsmith's "deserted village:" ... "and still the wonder grew that one small head could carry all he _ought to know_" [never lose sight of fact for the sake of rhyme.] in general terms, his duties consist of: . military surveys and explorations. . boundary surveys. . geodetic and hydrographic survey of the great lakes. . building fortifications--both permanent works and temporary or field works. . constructing military roads. . pontoniering or building military bridges, both with the regular bridge trains and with improved materials. . the planning and directing of siege operations, either offensive or defensive; sapping, mining, etc. . providing, testing and planting torpedoes for harbor defense when operating from shore stations. . staff duty with general officers. . improving rivers and harbors. . the building and repairing of lighthouses. . various special duties as commissioner of district of columbia, superintendent military academy, commandant engineer school, instructors at both of these schools, attaches to several foreign legations, for the collection of military information, etc. it would, of course, exceed the proper limits of a single lecture to go into the details of these many duties, but we may take only a passing glance at most of them, and give more special attention to a few that may involve some points of interest. perhaps the most interesting branch of the subject would be that of permanent fortifications, or what amounts to almost the same thing in this country, sea coast defenses. and here our trouble begins, for, while civil engineers have constant experience to guide them, their roads, bridges, and other structures being in constant use, the military engineer has only now and then, at long intervals, a war or a siege of sufficient extent to furnish data upon which he can safely plan or build his structures. imagine a civil engineer designing a bridge, road, or a dam to meet some possible future demand, without having seen such a structure used for twenty years or more, and you can form some estimate of the delightful uncertainties that surround the military engineer when called upon to design a modern fort. the proving ground shows him that radical improvements are necessary, but actual service conditions are almost entirely wanting, and such as we have contradict many of the proving ground theories. thus we have the records of shot going through inches of iron or feet of concrete on the proving ground; but such actual service tests as the bombardment of fort sumter, fort fisher, and the forts at alexandria contradict this entirely, and indicate that, except for the moral effect, our old forts, with modern guns in them and some additional strengthening at their weaker points, would answer all purposes so far as bombardment from fleets is concerned. this is not saying that the forts are good enough in their present condition, but simply that they can readily be made far superior in strength, both offensive and defensive, to any fleet that could possibly be provided at anything like the same expense, or in fact at any expense that would be justified by the condition of our treasury, either past, present, or probable future. it might be added that a still more serious difficulty in the way of the military engineer, so far as practice and its consequent experiences are concerned, is that for many years past, until quite recently, there have been no funds either for experiments or actual work on fortifications, so that very little has been done on them during the last twenty years. without going into the question of the necessity for sea coast defenses, we may assume that an enemy is likely to come into one of our harbors and that it is desirable to keep him out. what provisions must be made to accomplish this, i.e., to secure the safety of the harbors and the millions of dollars' worth of destructible property concentrated at the great trade centers that are usually located upon those harbors? we must first take a look at the enemy and see what he is like before we can decide what will be needed to repel his attack. for this purpose we need not draw on the imagination, but we may simply examine some of the more recent armadas sent to bombard seaports. for example, the fleet sent by great britain to bombard the egyptian city of alexandria, in . this fleet consisted of eight heavy ironclad ships of from , to , tons displacement and five or six smaller vessels; and the armament of this squadron numbered more than one hundred guns of all calibers, from the sixteen inch rifle down to the seven inch rifle, besides several smaller guns. but this fleet represented only a small fraction of england's naval power. during some recent evolutions she turned out thirty-six heavy ironclads and forty smaller vessels and torpedo boats. the crews of these vessels numbered nearly , officers and men, or about three times the entire number in our navy. such a fleet, or, more likely, a much larger one, might appear at the entrance say of new york harbor within ten days after a declaration of war, and demand whatever the nation to which it belonged might choose, with the alternative of bombardment. the problem of protecting our people and property from such attacks is not a new one, and, in fact, most of the conditions of this problem remain the same as they were fifty years ago, the differences being in degree rather than in kind. the most natural thought would be to meet such a fleet by another fleet, but the folly of such a course will become apparent from a moment's consideration. the difficulties would be: st. our fleet must be decidedly stronger than that of the enemy, or we simply fight a duel with an equal chance of success or failure. d. in such a duel the enemy would risk nothing but the loss of his fleet, and even a portion of that would be likely to escape, but we would not only risk a similar loss, but we would also lose the city or subject it to the payment of a heavy contribution to the enemy. d. unless we have a fleet for every harbor, it would be impossible to depend upon this kind of defense, as the enemy would select whichever harbor he found least prepared to receive him. it would be of vital importance that we defend every harbor of importance, as a neglect to do so would be like locking some of our doors and leaving the others open to the burglars. th. it might be thought that we could send our fleet to intercept the enemy or blockade him in his own ports, but this has been found impracticable. large fleets can readily escape from blockaded harbors, or elude each other on the high seas, and any such scheme implies that we are much stronger on the ocean than the enemy, which is very far from the case. to build a navy that would overmatch that of great britain alone would not only cost untold millions, but it would require many years for its accomplishment; and even if this were done, there would be nothing unusual in an alliance of two or more powerful nations, which would leave us again in the minority. _fleets, then, cannot be relied on for permanent defense_. again, it may be said that we have millions of the bravest soldiers in the world who could be assembled and placed under arms at a few days' notice. this kind of defense would also prove a delusion, for a hundred acres of soldiers armed with rifles and field artillery would be powerless to drive away even the smallest ironclad or stop a single projectile from one. in fact, neither of these plans, nor both together, would be much more effective than the windmills and proclamations which irving humorously describes as the means adopted by the early dutch governors of new york to defend that city against the swedes and yankees. having considered some of the means of defense that will _not_ answer the purpose, we may inquire what means _will be_ effective. and here it should be noted that our defenses should be so effective as not only to be reasonably safe, but to be so recognized by all nations, and thus discourage, if not actually prevent, an attack upon our coast. in the first place, we must have heavy guns in such numbers and of such sizes as to overmatch those of any fleet likely to attack us. these guns must be securely mounted, so as to be worked with facility and accuracy, and they must be protected from the enemy's projectiles at least as securely as his guns are from ours. merely placing ourselves on equal terms with the enemy, as in case of a duel or an ancient knight's tournament, will not answer, first, because such a state of things would invite rather than discourage attack, and secondly, because the enemy would have vastly more to gain by success and vastly less to lose by failure than we would. this can be accomplished much easier than is generally supposed, either by earthen parapets of sufficient thickness or by iron turrets or casements. it is evident that the weight of metal used in these structures may be vastly greater than could be carried on shipboard. great weight of metal is no objection on land, but, aside from its cost, is a positive advantage. this is evident when we consider the enormous quantity of energy stored in the larger projectiles moving at high velocities. for example, we often hear of the sixteen inch rifle whose projectile weighs about one ton, and this enormous mass projected at a velocity of , feet per second would have a kinetic energy of , foot tons, or it would strike a blow equal to that of ten locomotives of tons each running at miles an hour and striking a solid wall. any structure designed to resist such ponderous blows must, therefore, have enormous weight, or it will be overturned or driven bodily from its foundations. if the armor itself is not thick enough to give the required weight as well as resistance to penetration, the additional stability must be supplied by re-enforcing it with heavy masses of metal or masonry. it is evident, therefore, that _quality_ of metal is less important than _quantity_, and that so long as it is sufficiently tough to resist fracture, a soft, cheap metal, like wrought iron or low steel, is better adapted for permanent works than any of the fancy kinds of armor that have been tested for naval purposes. as an illustration of this, we may compare compound or steel-faced armor with wrought iron as follows: the best of the former offers only about one-third greater resistance to penetration than the latter, or inches of compound armor may equal inches of wrought iron, but the cost per ton is nearly double; so that by using wrought iron we may have double the thickness, or inches, which would give more than double the resistance to penetration, in addition to giving double the stability against overturning or being driven bodily out of place. but our guns may be reasonably well protected by earthen parapets without any expensive armor by so mounting them that when fired they will recoil downward or to one side, so as to come below the parapet for loading. this method of mounting is called the disappearing principle, and has been suggested by many engineers, some of whose designs date back more than one hundred years. we may also mount our guns in deep pits, where they will be covered from the enemy's guns, and fire them at high elevation, so that the shell will fall from a great height and penetrate the decks of the enemy's ships. this is known as mortar firing, but the modern ordnance used for this purpose is more of a howitzer than a mortar, being simply short rifled pieces arranged for breech loading. all our batteries should, of course, be as far from the city or other object to be protected as possible, to prevent the enemy from firing over and beyond the batteries into the city. but, with all these precautions, the enemy might put on all steam and run by us either at night or in a dense fog, and we must have some means of holding him under the fire of our guns until his ships can be disabled or driven away. this object is sought to be accomplished by the use of torpedoes anchored in the channels and under the fire of our guns, so that they cannot be removed by the enemy. these torpedoes are generally exploded by electricity from batteries located in casements on shore, these casements being connected with the torpedoes by submarine cables. it is easy to see how the torpedo may be so arranged that when struck by a ship the electric current will be closed, and, if the battery on shore is connected at the same instant, an explosion will take place; on the other hand, if the battery on shore is disconnected a friendly ship may pass in safety over the torpedoes. many ingenious contrivances have also been devised by which the torpedo may be made to signal back to the shore station either that it has been struck or that it is in good order for service, in case the enemy should undertake to run over it. one simple plan for this is to have a small telephone in the torpedo with some loose buckshot on the diaphragm, which is placed in a horizontal position, and will be slightly tilted as the torpedo is moved about by the waves. by connecting the shore end of the cable with a telephone receiver, the rolling of the shot may be distinctly heard if the torpedo is floating properly, but if sunk at its moorings, or if the cable is broken, no sound will be heard. the use of torpedoes involves the use of both electricity and high explosives, and a careful study based upon actual experiments has been carried on for many years, by the engineers and naval officers in all civilized countries. some of these experiments have supplied interesting and useful data, for the use of the agents in question, for various industrial purposes. another form of torpedo is that known as the locomotive torpedo, of which there are several kinds; some are propelled by liquid carbonic acid, which is carried in a strong tank and acts through a compact engine in driving the propeller. one of these is steered by electricity from the shore, and is known as the lay-haight torpedo, and can run twenty-five miles per hour. the whitehead torpedo is also propelled by liquid carbonic acid, but is not steered from shore. its depth is regulated by an automatic device actuated by the pressure of the water. the howell torpedo is driven by a heavy fly wheel which is set in rapid rotation just before the torpedo is launched. it has but a short range and is intended for launching from ships. another torpedo is propelled and steered from shore by rapidly pulling out of it two fine steel wires which, in unwinding, drive the twin screw propellers. this is the brennan torpedo. the sims-edison torpedo is both propelled and steered by electricity from the shore, transmitted to a motor and steering relay in the torpedo by an insulated cable. this cable has two cores and is paid out by the torpedo as it travels through the water just as a spider pays out its web. the cable is about half an inch in diameter and two miles long, and the torpedo can be driven at about eighteen miles per hour with a current of thirty amperes and , volts pressure. still another auxiliary weapon of defense is the dynamite gun, or rather, a pneumatic gun, that throws long projectiles carrying from to pounds of dynamite, to a distance of about two miles. the shells are arranged to explode soon after striking the water, by an ingenious battery that ignites the fuse as soon as the salt water enters it. the gun, which is known as the zalinski gun, is some sixty feet long and fifteen inches in caliber, the compressed air being suddenly admitted to it from the reservoirs at any desired pressure by a special form of valve that regulates the range. these guns are to be mounted in deep pits and fired at somewhat higher elevations than ordinary guns, but it has great accuracy within reasonable limits of range. field fortifications. in field fortification an enormous quantity of work was done during our last war. washington, richmond, nashville, petersburg, norfolk, new berne, plymouth, vicksburg, and many other cities were elaborately fortified by field works which involved the handling of vast quantities of earth, and, where the opposing lines were near together, ditches, abbatis, ground torpedoes, and wire entanglements were freely used. in some cases the same ground was fortified in succession by both armies, so that the total amount of work expended, in this way, would have built several hundred miles of railway. around richmond and petersburg alone the development of field works was far greater than wellington's celebrated lines at torres vedras. in all future wars, when large armies are opposed to each other, it is probable that field works will play even a more important part than in the past. the great advantage of such works, since the introduction of the deadly breech loading rifles and machine guns, was shown at plevna, where the russians were almost annihilated in attempting to capture the turkish intrenchments. sieges. it is not proposed to go into historical or other details of this branch of the subject, but to give in a condensed form some account of siege operations. according to the text books, the first thing to be done, if possible, in case of a regular siege, is to "invest" the fortress. this is done by surrounding it as quickly as possible with a continuous line of troops, who speedily intrench themselves and mount guns bearing outward on all lines of approach to the fortress, to prevent the enemy from sending in supplies or re-enforcements. as this line must be at considerable distance from the fort, it is usually quite long, and so is its name, for it is called the line of "circumvallation." inside of this line is then established a similar line facing toward the fort, to prevent sorties by the garrison. this line is called the line of "countervallation," and should be as close to the fort as the range of its guns and the nature of the ground will permit. from this line the troops rush forward at night and open the trenches, beginning with what is called the first parallel, which should be so laid out as to envelop those parts of the fort which are to be made the special objects of attack. from this first parallel a number of zigzag trenches are started toward the fort and at proper intervals other parallels, batteries, and magazines are built; this method of approach being continued until the besieged fort is reached, or until such batteries can be brought to bear upon it as to breech the walls and allow the attacking troops to make an assault. during these operations of course many precautions must be observed, both by the attacking and defending force, to annoy each other and to prevent surprise, and the work is mostly carried on under cover of the earth thrown from the trenches. these operations were supposed to occupy, under normal conditions, about forty-one days, or rather nights, as most of the work is done after dark, at the end of which time the fort should be reduced to such a condition that its commander, having exhausted all means of defense, would be justified in considering terms of surrender. the _theoretical journal_ of the siege prescribes just what is to be done each day by both attack and defense up to the final catastrophe, and this somewhat discouraging outlook for the defenders was forcibly illustrated by the late captain derby, better known by the reading public as "john phoenix," who, when a cadet, was called upon by professor mahan to explain how he would defend a fort, mounting a certain number of guns and garrisoned by a certain number of men, if besieged by an army of another assumed strength in men and guns, replied: "i would immediately evacuate the fort and then besiege it and capture it again in forty-one days." of course the fallacy of this reasoning was in the fact that the besieging army is generally supposed to be four or five times as large as the garrison of the fort; the primary object of forts being to enable a small force to hold a position, at least for a time, against a much larger force of the enemy. sieges have changed with the development of engines of war, from the rude and muscular efforts of personal prowess like that described in ivanhoe, where the black knight cuts his way through the barriers with his battle axe, to such sieges as those at vicksburg, petersburg, and plevna, where the individual counted for very little, and the results depended upon the combined efforts of large numbers of men and systematic siege operations. it should also be noticed that modern sieges are not necessarily hampered by the rules laid down in text books, but vary from them according to circumstances. for example, many sieges have been carried to successful issues without completely investing or surrounding the fortress. this was the case at petersburg, where general lee was entirely free to move out, or receive supplies and re-enforcements up to the very last stages of the siege. in other cases, as at fort pulaski, sumter, and macon, the breeching batteries were established at very much greater distances than ever before attempted, and the preliminary siege operations were very much abbreviated and some of them omitted altogether. this is not an argument against having well defined rules and principles, but it shows that the engineer must be prepared to cut loose from old rules and customs whenever the changed state of circumstances requires different treatment. military bridges. in the movement of armies, especially on long marches in the enemy's country, one of the greatest difficulties to be overcome is the crossing of streams, and this is usually done by means of portable bridges. these may be built of light trestles with adjustable legs to suit the different depths, or of wooden or canvas boats supporting a light roadway wide enough for a single line of ordinary wagons or artillery carriages. the materials for these bridges, which are known as ponton bridges, are loaded upon wagons and accompany the army on its marches, and when required for use the bridge is rapidly put together, piece by piece, in accordance with fixed rules, which constitute, in fact, a regular drill. the wooden boats are quite heavy and are used for heavy traffic, but for light work, as, for example, to accompany the rapid movements of the cavalry, boats made of heavy canvas, stretched upon light wooden frames, that are put together on the spot, are used. during gen. sherman's memorable georgia campaign and march to the sea, over three miles of ponton bridges were built in crossing the numerous streams met with, and nearly two miles of trestle bridges. in gen. grant's wilderness campaign the engineers built not less than thirty-eight bridges between the rappahannock and the james rivers, these bridges aggregating over , feet in length. under favorable circumstances such bridges can be built at the rate of to feet per hour, and they can be taken up at a still more rapid rate. when there is no bridge train at hand the engineer is obliged to use such improvised materials as he can get; buildings are torn down to get plank and trees are cut to make the frame. sometimes single stringers will answer, but if a greater length of bridge is required it may be supported on piles or trestles, or in deep water on rafts of logs or casks. but the heavy traffic of armies, operating at some distance from their bases, must be transported by rail, and the building of railway bridges or rebuilding those destroyed by the enemy is an important duty of the engineer. on the potomac creek, in virginia, a trestle bridge feet high and feet long was built in nine working days, from timber out of the neighborhood. another bridge across the etowah river, in georgia, was built in gen. sherman's campaign, and a similar bridge was also built over the chattahoochee. surveys and explorations. for more than half a century before the building of the great pacific railways, engineer officers were engaged in making surveys and explorations in the great unknown country west of the mississippi river, and the final map of that country was literally covered with a network of trails made by them. several of these officers lost their lives in such expeditions, while others lived to become more famous as commanders during the great rebellion. generals kearney, j.e. johnston, pope, warren, fremont and parke, and colonels long, bache, emory, whipple, woodruff and simpson, captains warner, stansbury, gunnison and many other officers, generally in their younger days, contributed their quota to the geographical knowledge of the country, and made possible the wonderful network of railways guarded by military posts that has followed their footsteps. their reports fill twelve large quarto volumes. boundary and lake surveys. the astronomical location of the boundaries of the several states and territories, as well as of the united states, is a duty frequently required of the engineer officer, and such a survey between this country and mexico is now in progress. the entire line of the th parallel of latitude from the lake of the woods to the pacific ocean, which forms our northern boundary, was located a few years ago by a joint commission of english and united states engineers, and monuments were established at short intervals over its entire length. a careful geodetic and hydrographic survey of the great northern lakes, including every harbor upon them and the rivers connecting them, was carried on for many years and was finally completed some ten years ago. maps and charts of these surveys are published from time to time for use of pilots navigating these waters. not only are the duties of the military engineer similar in many respects to those of the civil engineer, but there are many instances in which the duties of one branch of the profession have been performed by members of the other branch, quite as efficiently as though they had been performed by engineers specially educated for the purpose. during the late civil war there were many illustrations of this, all showing that an ingenious engineer can readily adapt himself to circumstances entirely different from those to which he has been accustomed. a very good example of this occurred in the red river expedition of general banks and admiral porter. in that memorable but disastrous campaign an army accompanied by a fleet of transports and light draught gunboats, sometimes called "tin clads" because some parts of them were covered with boiler plate to stop the bullets of the enemy, ascended the red river in louisiana; but the advance having been checked and a retreat commenced, it was found that the river had fallen to such a low state that the fleet was caught above the rapids near alexandria, and it would in all probability have been a complete loss had it not been for the timely application of engineering skill by lieut. col. joseph bailey, a civil engineer from wisconsin, who built a temporary dam across the river below the rapids and floated out the entire fleet. this dam was over feet long and in connection with some auxiliary dams raised the water level some ½ feet. it was built under many difficulties, but by the skill and ability of the engineer and the co-operation of the troops it was completed in ten days. another case was at the siege of petersburg, va., where lieut. col. pleasants, a pennsylvania coal miner, ran a gallery from our lines, under the rebel battery, some feet distant, and blew it entirely out of existence. the mine contained four tons of powder and produced a crater feet by feet and feet deep, and was completed in one month. the sequel to this was to be an attack on the enemy's line through the gap made by the explosion, and such an attack properly followed up would doubtless have had a marked effect in shortening the duration of the war, but this attack was so badly managed that it utterly failed and caused a severe loss to our own army. the mine itself, however, was a great success and produced a decided moral effect on both sides which lasted until the end of the war. it may be out of place to digress a moment to illustrate the moral effect of such a convulsion. several weeks after this great mine explosion, the th army corps, to which i then belonged, was holding a line of works recently captured from the rebels, about six miles from richmond, when one night the colonel commanding fort harrison, a large field work forming a part of this line, came down to headquarters and reported that some old pennsylvania coal miners in his command had heard mining going on under the fort. as the nearest part of the enemy's line was some yards from the fort, i was quite certain that they could not have run a gallery that distance in the time that had elapsed since we occupied the work, but there was of course the possibility that the mine had been partly built beforehand so as to be ready in just such a case as had arisen, viz., the capture of the fort by our troops. i therefore went with the colonel up to the fort to listen for the mining operations, and got the men who claimed to have heard the subterranean noises, down in the bottom of the ditch of the fort, which was ten feet deep, and at the angles formed a fairly good listening gallery, but nothing unusual could be heard. i therefore made arrangements to sink a line of pits in the bottom of the ditch, something like ordinary wells; the bottoms of these pits to be finally connected by a horizontal gallery which would envelop the fort and enable us to hear the enemy and blow him up, before he could get under the fort. although the commanding officer of that fort was as brave an officer as the war developed, he would not keep his men in the fort after dark, but withdrew them quietly to the flanks of the work, where they not only would be safe from an explosion, but would be ready to fall upon the enemy in case he should blow up the fort and rush in to capture the line, as our troops had attempted to do at petersburg. no explosion took place, however, and after our countermining work was completed, the garrison became reassured and remained in the fort at night as well as in day time. a few months later, when the enemy was driven from his lines, i went through his works to see whether any mining had been attempted, and found that a gallery leading toward fort harrison had been carried quite a distance, but was still incomplete, and it is barely possible that the old miners were right, after all, in thinking that they could hear the sound of the pick, although the distance was almost too great to make this theory very probable. still another illustration of the way in which civil engineers can make themselves extremely useful in military operations was the wonderful system of military railways, or railways operated for military purposes, that formed complete lines of transportation for the armies and their enormous quantities of supplies and munitions, more especially those in the west and southwest. construction trains were organized in the most complete style, and when a piece of track or a number of bridges were destroyed by the enemy, they would be rebuilt so rapidly that our trains would hardly seem to be delayed by it. the trains carried spare rails, ties, and bridges of various lengths ready to put up, and they also carried the necessary rolling stock and tools for destroying the roads and bridges of the enemy. so expert had this construction corps become that the enemy was ready to believe almost any statement in regard to it. general sherman tells of an instance where it was proposed to blow up a tunnel, to check his "march to the sea," when one of the men objected, saying it was of no use, for sherman had a duplicate tunnel in his train. although this is not a sermon, it may not be out of place to point out a few qualifications common to all engineers, for they all deal more or less with the same materials and forces and employ similar methods of investigation and construction. wood, iron, steel, copper and stone and their compounds are the materials of the civil, mining, mechanical and electrical, as well as of the military engineers. they all deal with the forces of gravitation, cohesion, inertia and chemical affinity. they all require skill, intelligence, industry, confidence, accuracy, thoroughness, ingenuity and, beyond all, sound judgment. wanting in any one of these qualifications, an engineer is more or less disqualified for important work. it is said that a distinguished engineer was always afraid to cross his own bridges, although built in the most thorough and approved manner. he was deficient in confidence. another engineer distinguished for his mathematical attainments built a bridge which promptly collapsed at the first opportunity. on overhauling his computations he ejaculated somewhat forcibly, "that confounded minus sign! it should have been plus." he was deficient in sound judgment, or what is sometimes called "horse sense." another and more common defect in young engineers is a want of thoroughness. it is generally best to go to the bottom of a question at first and keep at it until it is thoroughly and fully completed. confucius says, "if thou hast aught to do, first consider, second act, third let the soul resume her tranquillity." those who begin a great many things and never fully complete them lose a great deal of valuable time, but do very little valuable work. the way to avoid this difficulty is to be cautious about beginning things, but when once started don't leave it until you are satisfied to leave it for good. there is an arabian saying, "never undertake _all_ you can do, for he who undertakes _all_ he can do will frequently undertake _more_ than he can do." another common error is extravagance. on the plea that "the best is always the cheapest," and to be sure of a large factor of safety, or as the late mr. holley called it a "factor of ignorance," without much trouble to themselves, some engineers use more or better materials than the work requires, and thus greatly increase the cost without any corresponding advantage. almost any engineer can do almost anything in the way of engineering if not limited by the cost, but the man who knows just what materials to use and how to use them so that they will answer the purpose as to strength and durability can save his own salary to his employer many times over by simply omitting unnecessary expense. * * * * * how mechanical rubber goods are made. while the manufacture of rubber goods is in no sense a secret industry, the majority of buyers and users of such goods have never stepped inside of a rubber mill, and many have very crude ideas as to how the goods are made up. in ordinary garden hose, for instance, the process is as follows: the inner tubing is made of a strip of rubber fifty feet in length, which is laid on a long zinc-covered table and its edges drawn together over a hose pole. the cover, which is of what is called "friction," that is cloth with rubber forced through its meshes, comes to the hose maker in strips, cut on the bias, which are wound around the outside of the tube and adhere tightly to it. the hose pole is then put in something like a fifty foot lathe, and while the pole revolves slowly, it is tightly wrapped with strips of cloth, in order that it may not get out of shape while undergoing the process of vulcanizing. when a number of these hose poles have been covered in this way they are laid in a pan set on trucks and are then run into a long boiler, shut in, and live steam is turned on. when the goods are cured steam is blown off, the vulcanizer opened and the cloths are removed. the hose is then slipped off the pole by forcing air from a compressor between the rubber and the hose pole. this, of course, is what is known as hose that has a seam in it. for seamless hose the tube is made in a tubing machine and slipped upon the hose pole by reversing the process that is used in removing hose by air compression. in other words, a knot is tied in one end of the fifty foot tube and the other end is placed against the hose pole and being carefully inflated with air it is slipped on without the least trouble. for various kinds of hose the processes vary, and there are machines for winding with wire and intricate processes for the heavy grades of suction hose, etc. for steam hose, brewers', and acid hose, special resisting compounds are used, that as a rule are the secrets of the various manufacturers. cotton hose is woven through machines expressly designed for that purpose, and afterward has a half-cured rubber tube drawn through it. one end is then securely stopped up and the other end forced on a cone through which steam is introduced to the inside of the hose, forcing the rubber against the cotton cover, finishing the cure and fixing it firmly in its place. corrugated matting. after the mixing of the compound and the calendering, that is the spreading it in sheets, the great roll of rubber and cloth that is to be made into corrugated matting is sent to the pressman. here it is hung in a rack and fifteen or twenty feet of it drawn between the plates of the huge hydraulic steam press. the bottom plate of this press is grooved its whole length, so that when the upper platen is let down the plain sheet of rubber is forced into the grooves and the corrugations are formed. while in that position steam is let into the upper and lower platens and the matting is cured. after it has been in there the proper time, cold water is let into the press, it is cooled off, and the upper platen being raised, it is ready to come out. a simple device for loosening the matting from the grooves into which it has been forced is a long steel rod, with a handle on one hand like an auger handle, which, being introduced under the edge and twisted, allows the air to enter with it and releases it from the mould. packing. sheet packing is often times made in a press, like corrugated matting. the varieties, however, known as gum core have to go through a different process. usually a core is squirted through a tube machine and the outside covering of jute or cotton, or whatever the fabric may be, is put on by a braider or is wrapped about it somewhat after the manner of the old fashioned cloth-wrapped tubing. the fabric is either treated with some heat-resisting mixture or something that is a lubricant, plumbago and oil being the compound. other packings are made from the ends of belts cut out in a circular form and treated with a lubricant. there are scores of styles that make special claims for excellences that are made in a variety of ways, but as a rule the general system as outlined above is followed. jar rings. the old fashioned way of making jar rings was first to take a large mandrel and wrap it around with a sheet of compounded rubber until the thickness of the ring was secured. it was then held in place by a further wrapping of cloth, vulcanized, put in a lathe and cut up into rings by hand. that manner of procedure, however, was too slow, and it is to-day done almost wholly by machinery. for example, the rubber is squirted out of a mammoth tubing machine in the shape of a huge tube, then slipped on a mandrel and vulcanized. it is then put in an automatic lathe and revolving swiftly is brought against a sharp knife blade which cuts ring after ring until the whole is consumed, without any handling or watching.--_india rubber world_. * * * * * how enameled letters are made. the following is a description of a brief visit by a representative of the _journal of decorative art_ to the new factory of the patent letter and enamel company, ltd., situate in the east end of london. the company have recently secured a large freehold plot in the center of the east end of london, and have built for themselves a most commodious and spacious factory, some hundreds of feet in length, all on one floor, and commanded from one end by the manager's office, from whence can be seen at a glance the entire premises. the works are divided into two large compartments, and are lighted from the roof, ample provision being made for ventilation, and attention being given to those sanitary conditions which are, or should be, imperative on all well managed establishments. we first explore the stockroom. here are stored the numerous dies, of all sizes and shapes, which the company possess, varying in size from half an inch to twelve or sixteen inches. here, too, is kept the large store of thin sheet copper out of which the letters are stamped. our readers are familiar with the form or principle upon which these letters are made. it is simply a convex surface, the reverse side being concave, and being fixed on to the glass or other material with a white lead preparation. when these letters were first made, the practice was to cut or stamp them out in flat copper, and then to round or mould them by a second operation. recent improvements in the machinery, however, have dispensed with this dual process, and the stamping and moulding is done in the one swift, sharp operation. the process of making an enameled letter has four stages--stamping, enameling, firing, and filing. there are other and subsequent processes for elaborating, but those named are of the essence of the transaction. stamping. the stamping is done by means of presses, and is a very rapid and complete operation. the operator takes a piece of the sheet copper, places it on the press, the lever descends, there is a sharp crunching, bursting sound, and in a time shorter than it has taken to describe, the letter is made, sharp and perfect in every way. enameling. the letters are now taken charge of by a girl, who lays them out on a wire tray, the hollow side up, and paints them over with a thin mordant. while they are in this position, and before the mordant dries, they are taken on the gridiron-like tray to a kind of large box, which is full of the powdered enamel, and, holding the tray in her left hand, the girl takes a fine sieve full of the powder and dusts it over the letter, all superfluous powder falling through the open wirework and into the bin again, so that there is absolutely no waste. [illustration: dusting the letters before firing.] firing. the letters are now taken and placed carefully on thin iron disks or plates on the bench, where they remain until they are fired. it will be remembered that we said at the outset that the factory was divided into two large compartments, and it is into the second of these that we now go. here are ranged the series of furnaces which convert the copper and superincumbent enamel into one common body--fuse the one into the other. an unwary step soon warns us that we are too near the furnace, unless we want to run the risk of a premature cremation, and in the interests of the readers of this journal we step back to a respectful and proper distance, and watch the operations from afar. there seems to be something innately picturesque about all furnaces and those who work about them. whether it is the rembrandt effects produced by the strong light and shade, or whether it is that the necessary use of the long iron instruments, such as all furnace workers employ, compels a certain dignity and grace of poise and action, we know not; but certain it is that the grace is there in a marked degree, and as we watched the men take their long-handled iron tongs and place in or lift out the plates of hot metal, we could not fail to be impressed with the charm of the physical action they displayed. the disk containing the enameled letters is taken at the end of a long iron handle and carefully placed in a dome-shaped muffle. these muffles are all heated from the outside; that is, the fire is all round the chamber, but not in it, the fumes of the sulphur being destructive of the enamel if they are allowed to come into contact with it. so intense is the heat, however, that a muffle lasts only about nine days, and at the end of that time has to be renewed. [illustration: firing the letters] after the enamel is fused on to the copper, the disk is taken out and placed on a side slab, where it is allowed to cool. this process is repeated on the front side of the letter, when all that remains to complete it is the filing. [illustration: filing the letters after enameling.] this is done by girls, who, with very fine files, rub off the edges and any protuberances which may be there. every letter is subject to this operation, and all are turned out smooth and well finished. sometimes the letters are colored or further defined by the addition of a line, but the essentials are as we have already described. [illustration: mixing the enamel] brushing out. there are, however, one or two other operations of interest which we may notice. the company do not confine their exertions to the making of letters, various collateral developments having taken place which fill an important part in this scheme of work. of these, small tablets, containing advertisements or notices, such as we see in railway carriages, "push after raising window," or "close this door after you," or some legend pertaining to brown's soap or robinson's washing powder. these are done by different processes, the transfer process, as used in the potteries, being employed, but the one most largely used is that of "brushing out," which is done by plates. let us suppose that the tablet shows white letters on a dark ground, the _modus operandi_ is as follows: the tablet has been enameled, as already described, and is white. the operator now takes a dark enamel and spreads it evenly over the entire surface of the tablet. he, or she, now takes a stencil plate, of tinfoil, out of which the ground is cut, leaving the letter in the center. this is carefully placed over the tablet and held tight with the left hand, while with the right hand he holds a fine brush, which he uses with a quick, sharp movement over the surface. this action readily removes the unfired color from the hard, glassy surface underneath, and leaves a white letter. this is fired, and is then complete. sometimes two and, it may be, three plates are necessary to complete the brushing out, as ties must be left, as in the case of ordinary stencils, and these have to be brushed out with additional plates. two or three colors may be introduced by this process, but each separate color means separate firing. if the letters are dark on a light ground, the process is exactly the same, the stencil only being modified. in addition to the letters and tablets thus described, the company also undertake the production of large enameled signs, and to cope with the rapid expansion of this department of their work they are erecting special furnaces, to enable them to deal with any demand likely to be made upon them. the call for things permanent and washable in the way of advertising is on the increase, and the enameled plates made by the company is one of the most successful ways of meeting the demand. [illustration: "the smith a mighty man is he."] * * * * * burning brick with crude oil fuel. at the present time there is not the least reason why either wood, coal, or any other solid fuel should be used for the burning of brick. this style of burning brick belongs to a past age. the art of brickmaking has made tremendous progress during the past quarter of a century. it is no longer the art of the ignorant; brains, capital, experience, science, wide and general knowledge, must in these days be the property of the successful brick manufacturer. there are some such progressive brick manufacturers in chicago, who use neither coal nor wood in the drying or burning of their clay products. crude oil is the fuel which they employ, and with this fuel they obtain cheaper and better brick than do manufacturers who employ solid fuel. some of these manufacturers have expressed themselves as preferring to quit the brick business rather than return to the use of wood or coal as fuel in brick burning. this shows plainly that progress in our art, when it does come, comes to remain. it is true that crude oil for brick-burning purposes is not everywhere obtainable. but there is a fuel which is even better than crude oil, namely, fuel gas, and which can be produced and employed on any brick yard at a saving of seventy-five per cent. over coal or other solid fuel. the rose process for making fuel gas gives a water gas enriched by petroleum. roughly, about half the cost of this gas as made at bellefonte, pa., was for oil. the gas cost . c. per , cu. ft., with oil at ¼c. a gallon. at double this price the gas would cost but c., and show that in practice, foot for foot, it equals natural gas. fuel gas means a larger investment of capital than does any of the other modes of brick burning, and is, therefore, not within the reach of the entire trade. the cost of appliances for burning brick with crude oil is not very large, and as all grate bars, iron frames, and doors can be dispensed with in the use of crude oil fuel, the cost of an oil-burning equipment is but little in excess of an equipment of grates, etc., for coal-burning kilns. at works using small amounts of fuel, especially if cost of fuel bears but a small proportion to total cost of the manufactured product, oil will be in the future very largely used. it is clean, as compared with coal, can be easily handled, and when carefully used in small quantities, is safe. there are several methods of burning oil that are well adapted to the use of brick manufacturers and other fuel consumers. the pennsylvania railroad made some very thorough experiments on the use of petroleum in their locomotives, and while the results obtained are reported to have been satisfactory, it was the opinion of those having the experiments in charge that the demand for the pennsylvania railroad alone, were it to change its locomotives from coal to oil, would consume all the surplus and send up the price of oil to a figure that would compel a return to coal. it is true that production has enormously increased in the last three years, and the promise for the near future is that a high rate will be maintained. it is further true that the production of russia has increased enormously, and will probably be larger this year than ever before. this russian oil must go to markets and supply demands that have been met by american oil, and this will still further increase the amount of oil available for fuel purposes. there is no doubt, therefore, that petroleum has a future for fuel uses. many brick manufacturers are ready to use it, notwithstanding the possibility of an advance in its cost. while there are some objections to the use of petroleum as a fuel, growing chiefly out of the risk attending its storage and conveyance to the point of consumption, it is undoubtedly true that the chief objection is the fear that with the increased demand that would follow any extended use for this purpose would come an increase in price that would make its continued use too expensive. just four years ago, when the fuel oil industry was first projected, it was cried down because, as its enemies claimed, there was not enough oil fuel to be obtained in america to supply the new york city factories alone, to say nothing of other territory, and because of the high prices for oil that were sure to follow its substitution for coal fuel. since then the industry has experienced a magnificent success, the sales exceeding , , barrels a year, while the price is lower than ever. a curious impression seems to have gained ground to the effect that the standard oil company does not want to sell oil for fuel. it may be stated authoritatively that the company is not only able but willing to sell and deliver oil for fuel purposes in any quantity that may be desired. it is now delivering oil for fuel purposes in fourteen states of the union. for its sales in chicago and the west and northwest, the delivery is by tank cars from the terminus of the pipe line at south chicago, to which point it is pumped from lima, o. the chicago price is - / c. per gallon, or c. per barrel of gallons, f.o.b. cars at chicago. a great many of the brick manufacturers here and throughout the northwest are beginning to use crude petroleum as a substitute for soft coal. it is smokeless, for the fine spray of oil which comes from the injector consists of such minute drops of the liquid and is so thoroughly mixed with oxygen that when it burns the combustion is complete, and only steam and carbonic acid gas go out of the top of the kiln. not a speck of soot comes from the kiln or the smokestack or soils the whitewashed purity of the boiler room. oil fuel is absolutely clean. it is labor saving, too. no fireman has to keep shoveling coal, there are no ashes to be dragged out from under the furnace grates, and there are no clinkers to clog up the bars. one man, by turning a valve, may regulate the heat of a kiln containing one million brick. not only is it cleaner than coal and calls for less labor, but it is actually cheaper as a fuel. a barrel and a half of crude oil is equal for furnace fuel to a ton of the best illinois bituminous coal, and at c. a barrel any one can easily calculate the advantages petroleum has over its smoky rival. theoretically, two barrels of oil equal in heating power one ton of best pittsburg coal. an examination into the relative cost of the pittsburg and chicago coal to the oil consumed shows that the price of oil at pittsburg is c. per barrel of gallons, and slack coal can be purchased at from c. to c. per ton, and the best quality of lump coal at from $ . to $ . per ton, while the same quality of fuel can be bought in chicago at about c. a barrel, as against coal at from $ to $ . per ton. it would, therefore, look as though there could be no question whatever as to the economy and advantages to be derived from the use of oil as a fuel in this vicinity. the weight of oil required is less than half that of average coal to produce the same amount of steam. a great advantage in using oil as fuel in brick burning is that the fires are always under the absolute and direct control of the man in charge of the burning, who can regulate the volume of flame to the nicest degree and throw the heat to any part of the arches that he may desire. from present indications, oil will be the fuel adopted generally for generating power and for brick burning in chicago, as it saves the boilers, avoids grate bars, saves dirt and cinders, and reduces running expenses, etc. much skepticism was at first exhibited in chicago only a few years ago when one of the leading brick manufacturers attempted to burn a kiln of brick with coal for fuel. nearly all the brickmakers then in business put on wise looks and predicted the failure of the experiment with coal. but coal proved to be a better and cheaper fuel than wood, and in five or six years wood was used only for the kindling of the coal fires. then came the attempt to burn brick with crude oil, and the experiment having proved a success, coal has been banished from the leading brick yards in chicago and vicinity. the purington-kimball brick co., adams j. weckler, weber & la bond, the may-purington brick co., the union brick co., and the pullman brick co., all having headquarters in chicago, as well as the peerless brick co. and the pioneer fireproof construction co., both of ottawa, ill., are using crude oil fuel for brick burning. lima crude oil is used, and it is atomized by means of steam in small furnaces extending about two feet from the face of the brick kilns, and in which furnaces combustion occurs, and the conversion of the oil and steam into a gaseous fuel is secured. there is little doubt that the fuel employed in the future by the successful brick manufacturer must be in the gaseous form. owing to the enormous cost of handling coal, wood, and other crude fuel, and of removing the ash resulting from such fuel, it has been demonstrated in practice by the use of crude oil that the expense connected with the burning of brick can be reduced fully per cent. this large saving is made by converting crude petroleum into gas and utilizing this fuel, either directly in the arches of the kiln or by converting the crude oil into gas in a gas producer, and drawing this fuel gas from the producer and burning the same as required in kilns of suitable construction. crude oil fuel must in the future play an important part in all branches of manufacture requiring high, constant heats, and in which the cost of wood, coal, and other solid fuels, together with the labor cost of handling them, forms a considerable part of the cost of production. where coal is required to be hauled in carts from the wharves, or from a line of railway to the brick yard, located a mile, more or less, from the places where the coal is received, the cost of handling, haulage, and waste is an important item. added to these costs, the deterioration of soft coal under atmospheric influences and the waste from imperfect combustion and from the particles which fall from the grate bars into the ash pits, all eat a large hole in the brickmakers' profit. mr. d.v. purington, of chicago, ill., in speaking on this subject, says: "i will say that my fuel bill for oil is cheaper than it would cost me for coal. there is a very wide difference in the cost of unloading, hauling away ashes and cinders, and getting my coal around to the kiln, or boilers, or drier, or wherever i use it, and i get very much better results by being able to put the heat from oil fuel just where i want it." in order to secure the best results with any fuel it is not only necessary that a cheap fuel should be used, but that it should be always obtainable, and that all of it should be burned and turned to commercial account in the operations of brick manufacture. owing to the losses which we have previously mentioned, and resulting from the use of coal, this fuel is destined to be superseded by some form of fuel which will avoid such losses, and which will dispense with all of the inconveniences now encountered in the handling of coal and of the ashes resulting from combustion. wood is rapidly becoming too scarce and high near the great centers of man's habitation to be regarded in the present discussion. fully two hundred million of brick a year are being burned in the city of chicago with crude oil fuel, and a clamp kiln containing one million brick can be burned with crude oil in chicago at a labor cost of less than $ , and at a total cost for labor and oil of about c. per thousand brick. there are not, however, many places in the world where brick can be burned with oil at such a low cost as in the city of chicago; the reason being that oil is not everywhere obtainable so cheaply as in this city, and because few clays in the world are so easily burned into brick as are the clays of chicago. in milwaukee, wis., and in other places within a distance of miles from chicago, the time required to burn building brick with crude oil fuel averages from sixteen to twenty-one days, whereas the time of burning the chicago clays averages only about five days, and splendid "burns" have been secured there with crude oil in three and one-half days. it is evident, therefore, that the advantages of using crude oil fuel for the burning of brick will vary in different parts of the united states. where circumstances and the nature of the clay permit of its use, crude oil is, next to fuel gas, the brickmakers' ideal fuel.--_the brickmaker_. * * * * * investigation of a mound near jefferson city, mo. by a.s. logan. recently, a party consisting of engineers and employes of the missouri river improvement commission began an exploration of one of the mounds, a work of a prehistoric race, situated on the bluff, which overlooks the missouri river from an elevation of one hundred and fifty feet, located about six miles below jefferson city. this mound is one of about twenty embraced in a circle one quarter of a mile in diameter. the above party selected the mound in question apparently at haphazard; all the mounds presenting nearly a uniform outline, differing only in size and mostly circular in form, and from twenty to twenty-four feet at the base, rising to a height of eight feet and under. a trench was cut on a level with the natural soil, penetrating the mound about eight feet. a stone wall was encountered which was built very substantially, making access in that direction difficult, in consequence of which the earth was removed from the top for the purpose of entering from that direction. the earth was removed for a depth of four feet, when the top of the wall was exposed. further excavation brought to light human bones, some of them fairly well preserved, especially the bones of the legs. on the removal of these and a layer of clay, another layer of bones was exposed, but presenting a different appearance than the first, having evidently been burned or charred, a considerable quantity of charcoal being mixed with the bones. in this tier were found portions of several skulls, lying close together, as if they had been interred without regard to order. they were, in all probability, detached from the body when buried. the portions of the skulls found were those of the back of the head, no frontal bones being discovered. some jaw bones with the teeth attached were among the remains, but only that portion of the jaw containing the molar teeth. a few pieces of flint weapons were found in the upper layers, and nothing else of any significance. at this juncture the diggers abandoned the search, and some days later the writer, desirous of seeing all that was to be seen, resumed the work and removed the earth and remains until the bottom of the vault was reached; several layers being thus removed. all of these had evidently been burned, as charcoal and ashes were mixed with the bones of each succeeding layer. the layers were about an inch in thickness, with from two to four inches of earth between, and small flat stones, about the size of a man's hand, spread on each different layer, as if to mark its division from the next above. between the bottom layers, mixed with charcoal, ashes and small portions of burned bones were found what gives value to the search, numbering about fifty tools and a smoking pipe. the material of the tools is the same as the rock forming the vault, locally known as "cotton rock." i would consider it a species of sandstone. overlying the edge of "cotton rock" in the bluff is flint in great quantities, and in every conceivable shape, that these people could have resorted to had they been so disposed, and why they used the softer material i will leave to some archæologist to determine. the tools themselves are made after no pattern, but selected for their cutting qualities, as they all have a more or less keen edge which could be used for cutting purposes, and were no doubt highly prized, as they were found all in a pile in one corner of the vault and on top of which was found a stone pipe. the pipe is made bowl and stem together, and it is curious that people of such crude ideas of tools and weapons should manufacture such a perfect specimen of a pipe. it is composed of a very heavy stone, the nature of which would be difficult to determine, as it is considerably burned. a description of the vault will be found interesting to many. the wall of the vault rests upon the natural surface of the ground, about three feet high and eight and a half feet square, the inside corners being slightly rounded; it is built in layers about four inches in thickness and varying in length upward to three feet, neither cement nor mortar being used in the joints; the corners formed a sort of recess as they were drawn inward to the top, in which many of the stones were found. the stone for constructing the vault was brought from a distance of about a quarter of a mile, as there is none in sight nearer. i assume from all these circumstances that these people lived in this neighborhood anterior to the age of flint tools, as the more recent interments indicate that they were then entering upon the flint industry, and it may be that the "cotton rock" had become obsolete. these people buried their dead on the highest ground, covering and protecting them with these great mounds, when it would seem much easier to bury as at the present day; but instead, they, with great labor, carried the rock from a great distance, and it is reasonable to suppose, also, that the earth was brought from a distance with which they are surrounded, and piled high above, as there is no trace of an immediate or local excavation. in my view from the mounds and their surroundings i would unhesitatingly say the water, the foot hills of the glacier and the swamps left in its wake were but a short distance to the north of them, and during the summer months the melting ice would send a volume of water down this valley that the missouri river of to-day is but a miniature of, and therefore the highest hills were the only land that could be used by that ancient race. in this connection i would make the following suggestions that may lead to more important disclosures: my object is the hope of a more thorough investigation at some future time. nearer to the top of the mound was found, certainly, the remains of a people of more recent date than those found in the vault, as their bones were larger, which would indicate a more stalwart tribe, and also their mode of burial was different, as there was no indication of fire being used, as was the case with the lower burials. i would pronounce the upper interments those of indians of the present day; the tools found with these were weapons of the chase. on the other hand, those found in the vault were of a peaceful character, and their surroundings would readily comport, in my opinion, to the glacial period. the entire absence of flint in the bottom of the mound would show one of two things, either they were unacquainted with the use of flint or at that time there was no flint to be had. it is there now in great abundance, in such forms for cutting purposes that would render the "cotton rock" almost useless. the flint is found in a hill close to the river bank, about half a mile from the mound, and the upper portion of the ledge has the appearance, to me, of glacial action and probably forms a moraine, as it has, evidently, been pushed over the underlying ledge, and been ground and splintered in a manner that could not have been without great crushing force. it would be reasonable enough to suppose that the action of the river may have uncovered this flint by washing away the softer material since the occupation of the older race. in relation to the indian interment in the examined mound, i could not say distinctly whether the indian burials had been such as to make them aware of former burials or not, but i think from the thickness of the clay between the two that they were ignorant of former burials. the mounds of the modern indian, so far as my investigations are concerned, would indicate a more rudely formed structure which would appear to be an imitation of the older mounds, as they are not finished with like care nor have they the ulterior structures.--_the scientist_. * * * * * action of caustic soda on wood. by m.h. tauss. the researches of the author upon the action which water exerts upon wood at a high temperature have shown how much of the incrusting material can be removed without the aid of any reagent. in connection with the manufacture of cellulose, it is also interesting to prosecute at the same time experiments with solutions of the caustic alkalies, in order to study the mode of action upon both wood and pure cellulose. the manufacture of cellulose has for many years been an industry, and yet little or nothing from a chemical point of view is known of the action of caustic soda upon vegetable fibers. braconnot, in , obtained alumina by treating wood with an alkali, but the first application of wood to the manufacture of paper was due to chauchard. by boiling vegetable fibers with caustic lyes, collier and piette obtained cellulose. again, in , barne and blondel proposed to make cellulose in a similar way, but employed nitric acid in the place of soda. the first cellulose made exclusively from wood and caustic soda was produced at the manayunk wood pulp works, in , in the neighborhood of philadelphia, by burgess & watt. the operation consisted in treating the wood for six hours at a pressure of from six to eight atmospheres, with a solution of caustic soda of ° b. ungerer noticed that it was sufficient to limit the pressure from three to six atmospheres, according to the quality of the wood, and advised the use of solutions containing four to five per cent. of caustic soda. he employed a series of cylinders, arranged vertically, in which the wood was subjected to a methodical system of lixiviation. the same lye passed through many cylinders, so that when it made its exit at the end it was thoroughly exhausted, and the wood thus kept coming in contact with fresh alkaline solutions. according to the account of kiclaner, the disintegration of wood may be effected in the following four ways: . by heating direct in boilers at a pressure of atmospheres. (see dresel and rosehain.) . in vertical boilers heated direct or by steam, and kept at a pressure of from to atmospheres. (sinclair, nicol, and behrend.) . in revolving boilers, maintained at a pressure of atmospheres by direct steam. . by means of a series of small vessels communicating with each other, and through which a lye circulates at a pressure of six atmospheres. (ungerer.) this latter process is preferable to the others. researches have also been made by the author in order to ascertain the loss which wood and cellulose suffer at different temperatures or in contact with varying quantities of alkali (naho). the following is a _resumé_ of the experiments, giving the loss in per cent. resulting from a "cooking" of three hours duration: i. ordinary pressure: grms. cellulose, with c.c. of caustic soda solution, sp. gr. . . grms. of soft wood, treated as above . " hard " " " . ii. pressure of five atmospheres: grms. cellulose, with c.c. caustic soda solution of sp. gr. . . grms. of soft wood, treated as above . " hard " " " . iii. pressure of ten atmospheres: grms. of cellulose . " soft wood . " hard " . iv. ordinary pressure: grms. of cellulose, with c.c. caustic soda solution of sp. gr. . . grms. of soft wood . " hard " . v. pressure of five atmospheres: grms. of cellulose, with c.c. caustic soda solution of sp. gr. . . grms. of soft wood . " hard " . vi. ordinary pressure: grms. of cellulose, with c.c. caustic soda solution of sp. gr. . . grms. of soft wood . " hard " . vii. pressure of five atmospheres: grms. of cellulose, with c.c. of caustic soda solution of sp. gr. . . grms. of soft wood . " hard " . viii. pressure of ten atmospheres: grms. of cellulose, with c.c. caustic soda solution of sp. gr. . . grms. of soft wood . " hard " . from this it is evident that by increasing the temperature and pressure the solvent action of the alkali is increased, but the strength of the lye exercises an influence which is even more marked. thus, at a pressure of five atmospheres, the loss of cellulose was . with a caustic lye containing per cent. of naho, while it was only . with a lye of per cent. naho. to further elucidate the action of the alkali under the conditions given above, the author has estimated the amount of precipitate which alcohol gives with the soda solutions, after boiling with the wood: . . . specific gravity of naho solutions . . . soft wood, ordinary pressure . traces . " pressure of five atmospheres . . . " " ten " . . -- hard wood, ordinary pressure . . . " pressure of five atmospheres . . . " " ten " traces . . the estimation of the precipitate, produced in the soda solutions employed in the experiments cited above, gives: soft wood, ordinary pressure . traces . " pressure of five atmospheres . . . " " ten " . . -- hard wood, ordinary pressure . . " pressure of five atmospheres . . . " " ten " . . . as a general rule manufacturers employ a greater pressure than that which was found necessary by the author. as a result, it appears from these experiments that the wood not only loses incrusting matter, but that part of the cellulose enters into solution. as a matter of fact, the yield obtained in practical working from parts of wood does not exceed to per cent.--_le bull. fab. pap.; chemical trade journal._ * * * * * new boron compounds. an important paper is contributed by m. moissan to the current number of the _comptes rendus_, describing two interesting new compounds containing boron, phosphorus, and iodine. a few months ago m. moissan succeeded in preparing the iodide of boron, a beautiful substance of the composition bi_{ }, crystallizing from solution in carbon bisulphide in pearly tables, which melt at ° to a liquid which boils undecomposed at °. when this substance is brought in contact with fused phosphorus an intense action occurs, the whole mass inflames with evolution of violet vapor of iodine. red phosphorus also reacts with incandescence when heated in the vapor of boron iodide. the reaction may, however, be moderated by employing solutions of phosphorus and boron iodide in dry carbon bisulphide. the two solutions are mixed in a tube closed at one end, a little phosphorus being in excess, and the tube is then sealed. no external application of heat is necessary. at first the liquid is quite clear, but in a few minutes a brown solid substance commences to separate, and in three hours the reaction is complete. the substance is freed from carbon bisulphide in a current of carbon dioxide, the last traces being removed by means of the sprengel pump. the compound thus obtained is a deep red amorphous powder, readily capable of volatilization. it melts between ° and °. when heated _in vacuo_ it commences to volatilize about °, and the vapor condenses in the cooler portion of the tube in beautiful red crystals. analyses of these crystals agree perfectly with the formula bpi_{ }. boron phospho-di-iodide is a very hygroscopic substance, moisture rapidly decomposing it. in contact with a large excess of water, yellow phosphorus is deposited, and hydriodic, boric, and phosphorus acids formed in the solution. a small quantity of phosphureted hydrogen also escapes. if a small quantity of water is used, a larger deposit of yellow phosphorus is formed, together with a considerable quantity of phosphonium iodide. strong nitric acid oxidizes boron phospho-di-iodide with incandescence. dilute nitric acid oxidizes it to phosphoric and boric acids. it burns spontaneously in chlorine, forming boron chloride, chloride of iodine, and pentachloride of phosphorus. when slightly warmed in oxygen it inflames, the combustion being rendered very beautiful by the fumes of boric and phosphoric anhydrides and the violet vapors of iodine. heated in contact with sulphureted hydrogen, it forms sulphides of boron and phosphorus and hydriodic acid, without liberation of iodine. metallic magnesium when slightly warmed reacts with it with incandescence. when thrown into vapor of mercury, boron phospho-di-iodide instantly takes fire. the second phospho-iodide of boron obtained by m. moissan is represented by the formula bpi. it is formed when sodium or magnesium in a fine state of division is allowed to act upon a solution of the di-iodide just described in carbon bisulphide; or when boron phospho-di-iodide is heated to ° in a current of hydrogen. it is obtained in the form of a bright red powder, somewhat hygroscopic. it volatilizes _in vacuo_ without fusion at a temperature about °, and the vapor condenses in the cooler portion of the tube in beautiful orange colored crystals. when heated to low redness it decomposes into free iodine and phosphide of boron, bp. nitric acid reacts energetically with it, but without incandescence, and a certain amount of iodine is liberated. sulphuric acid decomposes it upon warming, without formation of sulphurous and boric acids and free iodine. by the continued action of dry hydrogen upon the heated compound the iodine and a portion of the phosphorus are removed, and a new phosphide of boron, of the composition b_{ }p_{ }, is obtained.--_nature_. * * * * * boron salts. a paper upon the sulphides of boron is communicated by m. paul sabatier to the september number of the _bulletin de la societe chimique. nature_ gives the following: hitherto only one compound of boron with sulphur has been known to us, the trisulphide, b_{ }s_{ }, and concerning even that our information has been of the most incomplete description. berzelius obtained this substance in an impure form by heating boron in sulphur vapor, but the first practical mode of its preparation in a state of tolerable purity was that employed by wohler and deville. these chemists prepared it by allowing dry sulphureted hydrogen gas to stream over amorphous boron heated to redness. subsequently a method of obtaining boron sulphide was proposed by fremy, according to which a mixture of boron trioxide, soot, and oil is heated in a stream of the vapor of carbon bisulphide. m. sabatier finds that the best results are obtained by employing the method of wohler and deville. the reaction between boron and sulphureted hydrogen only commences at red heat, near the temperature of the softening of glass. when, however, the tube containing the boron becomes raised to the temperature, boron sulphide condenses in the portion of the tube adjacent to the heated portion; at first it is deposited in a state of fusion, and the globules on cooling present an opaline aspect. further along the tube it is slowly deposited in a porcelain like form, while further still the sublimate of sulphide takes the form of brilliant acicular crystals. the crystals consist of pure b_{ }s_{ }; the vitreous modification, however, is usually contaminated with a little free sulphur. very fine crystals of the trisulphide may be obtained by heating a quantity of the porcelain-like form to ° at the bottom of a closed tube whose upper portion is cooled by water. the crystals are violently decomposed by water, yielding a clear solution of boric acid, sulphureted hydrogen being evolved. on examining the porcelain boat in which the boron had been placed, a non-volatile black substance is found, which appears to consist of a lower sulphide of the composition b_{ }s. the same substance is obtained when the trisulphide is heated in a current of hydrogen; a portion volatilizes, and is deposited again further along the tube, while the residue fuses, and becomes reduced to the unalterable subsulphide b_{ }s, sulphureted hydrogen passing away in the stream of gas. two selenides of boron, b_{ }se_{ } and b_{ }se, corresponding to the above described sulphides, have also been prepared by m. sabatier, by heating amorphous boron in a stream of hydrogen selenide, h_{ }se. the triselenide is less volatile than the trisulphide, and is pale green in color. it is energetically decomposed by water, with formation of boric acid and liberation of hydrogen selenide. the liquid rapidly deposits free selenium, owing to the oxidation of the hydrogen selenide retained in solution. light appears to decompose the triselenide into free selenium and the subselenide b_{ }se. silicon selenide, sise_{ }, has likewise been obtained by m. sabatier by heating crystalline silicon to redness in a current of hydrogen selenide. it presents the appearance of a fused hard metallic mass incapable of volatilization. water reacts most vigorously with it, producing silicic acid, and liberating hydrogen selenide. potash decomposes it with formation of a clear solution, the silica being liberated in a form in which it is readily dissolved by alkalies. silicon selenide emits a very irritating odor, due to the hydrogen selenide which is formed by its reaction with the moisture of the atmosphere. when heated to redness in the air it becomes converted into silicon dioxide and free selenium. * * * * * natural sulphide of gold. by t.w.t. atherton. the existence of gold in the form of a natural sulphide in conjunction with pyrites has often been advanced theoretically as a possible occurrence, but up to the present time this occurrence has, i believe, never been established as an actual fact. during my investigations on the ore of the deep creek mines, i have found in them what i believe to be gold existing as a natural sulphide. the description of this ore will, no doubt, be of interest to your readers. the lode is a large irregular one of pure arsenical pyrites, existing in a felsite dike near the sea coast. surrounding it on all sides are micaceous schists, and in the neighborhood is a large hill of granite about ft. high. in the lode and the rock immediately adjoining it are large quantities of pyrophylite, and in some places of the mine are deposits of this pure white, translucent mineral, but in the ore itself it is a yellow and pale olive green color, and is never absent from the pyrites. from the first i was much struck with the exceedingly fine state of division in which the gold existed in the ore. after roasting and very carefully grinding down in an agate mortar, i have never been able to get any pieces of gold exceeding the one-thousandth of an inch in diameter, and the greater quantity is very much finer than this. careful dissolving of the pyrites and gangue, so as to leave the gold intact, failed to find it in any larger diameter. as this was a very unusual experience in investigations on many other kinds of pyrites, i was led further into the matter. ultimately, after a number of experiments, there was nothing left but to test for gold as a sulphide. taking grammes of pyrites from a sample assaying ounces fine gold per ton, grinding it finely, and; heating for some hours with a solution of sodium sulphide (na_{ }s_{ }), on decomposing the filtrate and treating it for gold i got a result at the rate of ounces gold per ton. this was repeated several times with the same result. this sample came from the lode at the ft. level, while samples from the higher levels where the ore is more oxidized, although carrying the gold in the same degree of fineness, do not give as high a percentage of auric sulphide. it would appear that all the gold in the pyrites (and i have never found any apart from it) has originally taken its place there as a sulphide. the sulphide is an analysis of a general sample of the ore: silica . p.c. alumina . " lime . " sulphur . " arsenic . " iron . " cobalt . " per ton. nickel traces. gold ozs. dwts. grs. silver " " " ------- . nambucca head's gold mining company, deep creek, n.s. wales, oct. , .--_chemical news_. * * * * * some means of purifying water. there are several methods extant for the purpose of purifying and softening water, and in the following brief account some of the chief features of these methods are summarized. the slack and brownlow apparatus we will deal with first. this purifier is one which is intended to remove the matter in suspension in the water to be treated by subsidence and not by filtration. the apparatus consists of a vertical iron tank or cylinder, inside which are a series of plates arranged in a spiral direction around a fixed center, and sloping at an angle of ° on both sides outward. the water to be dealt with flows through a large inlet tube fixed to the bottom of the cylinder, rises to the top by passing spirally round the whole circumference, and depositing on the plates or shelves all solids and impurities at the outer edges of the plates. mud cocks are placed to remove the solids deposited during the flow of the water upward to the outlet pipe, placed close to the top of the cylinder. one of these tanks, a square one, is at work purifying the medlock water at manchester, and on drawing samples of water from nearly every plate, that from the lower mud cock showed considerable deposit, which decreased in bulk until the top mud cock was reached, when the water was quite free from deposit. it is stated that one man would be sufficient to attend to of these purifiers. to filter or purify , , gallons per hours would require tanks, ft. by ft. diameter, each doing , gallons per hour, and would cost, with their fittings, £ , , including all patent rights, but exclusive of lime mixing tanks, agitators, lime water and softening tanks, engine and boiler, and suitable buildings, the cost of which would not be far short of £ , , or a total of £ , to soften , , gallons per hours. the labor and other working expenses in connection with this plant would not be less than that necessary to work the porter-clark process, which is given as o. d. per , gallons. the brock and minton filter press system is another method. this patent press is made of steel, perforated with ½ inch holes. on the inside of the shell there is first laid a layer of fine wire netting, then a layer of cloth, and lastly another layer of wire netting of a larger mesh than the other. the matter treated is pumped into the body of the cylinder, the liquid passing through the filtering material to the outside, the solids being retained inside, and are got rid of by partially revolving the upper half to relieve it from the knuckle joint, and, after being raised, the lower half is turned over by machinery, and the solid matter is simply allowed to fall out into wagons or trucks run underneath for that purpose. such, in brief, is the manner of using this filter press for chemical works' purposes. the cost of each filter press, including royalties, is from £ to £ , the size being ft. by ft. diameter. having a filtering area of square feet, it would require of these applied to softening water to effectually deal with , , gallons per hours; this, at the lowest estimate for filters alone, would be £ , , and, using the same figures, £ , for lime mixing tanks, etc., as referred to in the "slack and brownlow" purifier, would bring the total cost up to £ , , and the working expense would not be less than that required to work the porter-clark process, and would probably be very much greater. this filter press is not in use anywhere for dealing with large quantities of water in connection with a town water supply. a process which has been working for a long time at southampton is the atkins system, which also includes the use of filter presses. the pumping station and softening works are situated at otterbourne, eight miles from southampton, and were built together as one scheme. the mixing room has two slaking lime tanks, with agitators driven by steam power. the mixture is then run as cream of lime into a tank ft. square and is then pumped into the lower ends of two lime water producing cylinders. the agitation is here obtained by pressure from a small cistern placed above them with a ft. head, the pipe from which is attached to the lower ends of the cylinders. this has been found by experiment to be the most satisfactory means of obtaining the proper degree of agitation necessary; the clear lime water is then drawn off at the top of the cylinders, and flows by gravity into a mixer, where it comes in contact with the hard water. both flow together into a distributing trough, from which it overflows into a small softening reservoir, having a capacity of one hour's supply, a weir being placed along the lower end, over which the water flows to filter presses. the clear water from the filters is then conveyed to a small well, from which the permanent engines raise it to the first of a series of high level covered service reservoirs. in the filter press there are hollow disks representing a filtering area of square feet, or a total of , square feet. the water to be filtered passes into the body of the filter and then through a filtering medium of cloth laid on a thin perforated zinc plate, into the inner side of the disks, from whence it is conveyed through the hollow shaft, to which the disks are attached, to the high level pumps. the filter cloths are cleaned three times every hours, without removal, by jets of softened water from the main, having a pressure of pounds to the square inch. during cleaning operations the disks are made to revolve slowly; this only occupies a space of five minutes for each cleaning. the cloths last from six to eight months without being renewed. they also occasionally use for further cleaning the cloths a jet of steam injected upon the center of the disks in order to remove by partial boiling the insoluble particles engrained in the cloths. this has been found to make the cloths last longer. this cloth is obtained from porritt bros. and austen, stubbing vale, ramsbottom, and costs ½d. per lineal yard of a width to suit the disks. the quantity softened is ¼ million gallons per hours, but the present plant can deal with ½ million gallons, and the buildings are erected for ½ million gallons, additional filters and lime producing tanks being only required to deal with the increased quantity. the costs of the softening works was £ , , of which £ , was for the softening machinery and plant and £ , for the reservoir, buildings, etc. the working expenses, including lime, labor, cloths, general repairs, and steam, is stated to be . d. per , gallons, the labor required being only two men, one on the day and the other on the night shift, with an occasional man to assist. the hardness of the southampton water on clark's scale is ° of total hardness, and this is reduced down to ° or ° by this process.--_chem. tr. jour._ * * * * * a new laboratory process for preparing hydrobromic acid. by g.s. newth. this method is a synthetical one, and consists in passing a stream of hydrogen and bromine vapor over a spiral of platinum wire heated to bright redness by means of an electric current. a glass tube, about inches long and / of an inch bore, is fitted at each end with a cork carrying a short straight piece of small tube; through each cork is also fixed a stout wire, and these two wires are joined by means of a short spiral of platinum wire, the spiral being about inch long. one end of this apparatus is connected to a small wash bottle containing bromine, through which a stream of hydrogen can be bubbled. the other end is attached to a tube dipping into a vessel of water for the absorption of the gas, or, if a large quantity of the solution is required, to a series of woulf's bottles containing water. hydrogen is first slowly passed through the tube until the air is displaced, when the platinum spiral is heated to bright redness by the passage of a suitable electric current. complete combination takes place in contact with the hot wire, and the color imparted to the ingoing gases by the bromine vapor is entirely removed, and the contents of the tube beyond the platinum are perfectly colorless. the vessel containing the bromine may be heated to a temperature of about ° c. in a water bath, at which temperature the hydrogen will be mixed with nearly the requisite amount of bromine to combine with the whole of it. so long as even a slight excess of hydrogen is passing, which is readily seen by the escape of bubbles through the water in the absorbing vessels, the issuing hydrobromic acid will remain perfectly colorless, and therefore free from bromine; so that it is not necessary to adopt any of the usual methods for scrubbing the gas through vessels containing phosphorus. when the operation is proceeding very rapidly a lambent flame occasionally appears in the tube just before the platinum wire, but this flame is never propagated back through the narrow tube into the bromine bottle. the precaution may be taken, however, of plugging this narrow tube with a little glass wool, which renders any inconvenience from this cause quite impossible. by this method a large quantity of bromine may be rapidly converted into hydrobromic acid without any loss of bromine, and the operation when once started can be allowed to proceed without any further attention.--_chemical news._ * * * * * sapotin: a new glucoside. by gustave michaud. _achras sapota, l._, is a large tree scattered through the forests of central america and the west indies; its fruit is often seen upon the creole dinner table. this fruit is a berry, the size of an orange, the taste of which suggests the flavor of melon, as well as that of hydrocyanic acid. the fruit contains one or two seeds like large chestnuts, which, if broken, let fall a white almond. this last contains the glucoside which i call _sapotin_. i obtained sapotin for the first time by heating dry raspings of the almond with per cent. alcohol. while cooling, the filtered liquid deposited a good deal of the compound. since that time i have advantageously modified the process and increased the amount of product. i prepare sapotin in the following way: the almonds are rasped, dried at ° c. and washed with benzene, which takes away an enormous quantity of fatty matter. the benzene which remains in the almond is driven put first by compression, afterward by heating. then the raspings are exhausted with boiling per cent. alcohol. the solution is filtered as rapidly as possible, in order to avoid its cooling and depositing the sapotin in the filter. as soon as the temperature of the filtered liquid begins to fall, a voluminous precipitate is seen to form, which is the sapotin. in order to purify it, the precipitate is collected in a filter and expressed between sheets of filter paper. when dry it is washed with ether, which takes away the last particles of fatty and resinous matter. the purification is completed by two crystallizations from per cent. alcohol. at last the substance is dried at °. the sapotin separates from its alcohol solution in the form of microscopic crystals. when dry, it is a white, inodorous powder. its taste is extremely acrid and burning. if the powder penetrate into the nostrils or the eyes, it produces a persistent burning sensation which brings about sneezing and flow of tears. it melts at ° c., growing brown at the same time. it has a laevo-rotatory power of [a]_{j} = - . , which was determined with an alcoholic solution, the aqueous solution not being sufficiently transparent. it is very soluble in water, easily soluble in boiling alcohol, much less in cold alcohol, and insoluble in ether, chloroform and benzene. its alcoholic solution is precipitated by ether. tannin has no action on it, but basic acetate of lead produces a gelatinous precipitate in its aqueous solution. strange enough, this precipitate is entirely soluble in a small excess of basic acetate of lead. if thrown into concentrated sulphuric acid, sapotin colors it with a garnet red tint. it does not reduce fehling's solution. its analysis gave the following results: calculated for found. c_{ }h_{ }o_{ }. i. ii. c . . . h . . . when heated with water and a little sulphuric acid, sapotin is decomposed and yields glucose and an insoluble matter which i call _sapotiretin_. one hundred parts of sapotin produce . parts of glucose and . of sapotiretin. the equation which represents this reaction is: c_{ }h_{ }o_{ } + h_{ }o = c_{ }h_{ }o_{ } + c_{ }h_{ }o_{ } and requires per cent. of glucose and per cent. of sapotiretin. sapotiretin is an amorphous compound, insoluble in water, very soluble in alcohol, less soluble in chloroform, insoluble in ether. below is the result of its analysis: calculated for found. c_{ }h_{ }o_{ }. i. ii. c . . . h . . . --_amer. chem. jour._ * * * * * detection of peanut oil in olive oil. holde, after a careful trial of the various processes for detecting the above adulteration, gives the preference to renard's, which he describes as follows: ten grms. of the suspected oil, after being saponified, and the fatty acids separated by hydrochloric acid, are dissolved in per cent. alcohol, and precipitated by sugar of lead. the oleate of lead is separated by ether, and the residuum, consisting of palmitic and arachic acids, is decomposed by hydrochloric acid. the fatty acids are dissolved, with the aid of heat, in c.c. of per cent. alcohol. the arachic acid which separates after cooling is filtered out and washed, first with per cent. and afterward with per cent. alcohol. it is then dissolved in hot alcohol, and the solution evaporated in a weighed saucer. the weight of the residuum, after taking into account the acid dissolved in the alcohol, equals the whole amount of arachic acid contained in the oil; the melting point of this residuum should be ° to ° c. with this process the author has always been successful; but when the olive oil contains not more than to per cent. of peanut oil, it is necessary to make the test with grms. of the former, otherwise the melting point of the arachic acid cannot be estimated. furthermore, the acids which are separated from the lead salt by hydrochloric acid must be recrystallized repeatedly with per cent. alcohol, until the melting point ceases to rise, in case the latter is not found to exceed ° c. at the first estimation. when peanut oil is present, the melting point will always be above °.--_chem. zeit._ * * * * * hydroxylamine. free hydroxylamine, nh_{ }oh, has been isolated by m. lobry de bruyn, and a preliminary account of its mode of preparation and properties is published by him in the current number of the _recueil des travaux chimiques des pays-bas_ ( , , ). the manner in which the free base was obtained was briefly as follows. about a hundred grammes of hydroxylamine hydrochloride, nh_{ }oh.hcl, were dissolved in six hundred cubic centimeters of warm methyl alcohol. to this solution a quantity of sodium dissolved in methyl alcohol was added, in such proportion that the hydrochloride of hydroxylamine was present in slight excess over and above that required to convert it to sodium chloride. after deposition of the separated sodium chloride the solution was decanted and filtered. the greater portion of the methyl alcohol was next removed by distillation under the reduced pressure of - mm. the remainder was then treated with anhydrous ether, in order to completely precipitate the last traces of dissolved sodium chloride. the liquid eventually separated into two layers, an upper ethereal layer containing about per cent. of hydroxylamine, and a lower layer containing over per cent. of hydroxylamine, the remainder of the methyl alcohol, and a little dissolved salt. by subjecting this lower layer to fractional distillation under mm. pressure, it was separated into three fractions, of which the first contained per cent. of hydroxylamine, the second per cent., and the third crystallized in the ice-cooled receiver in long needles. this third fraction consisted of free solid nh_{ }oh. hydroxylamine as thus isolated in the free state is a very hygroscopic substance, which rapidly liquefies when exposed to air, owing to the absorption of water. the crystals melt at °, and the fused substance appears to possess the capability of readily dissolving metallic salts. sodium chloride is very largely soluble in the liquid; powdered niter melts at once in contact with it, and the two liquids then mix. free hydroxylamine is without odor. it is heavier than water. when rapidly heated upon platinum foil it suddenly decomposes in a most violent manner, with production of a large sheet of bright yellow flame. it is only very slightly soluble in liquid carbon compounds, such as chloroform, benzene, ether, acetic ether, and carbon bisulphide. the vapor attacks corks, so that the solid requires to be preserved in glass-stoppered bottles. the free base appears also to act upon cellulose, for, upon placing a few drops of the melted substance upon filter paper, a considerable amount of heat is evolved. the pure crystals are very stable, the base in the free state appearing to possess much greater stability than when dissolved in water. the instability of the solution appears, however, to be influenced to a considerable extent by the alkalinity of the glass of the containing vessel, for concentrated solutions free from dissolved alkali are found to be perfectly stable. bromine and iodine react in a remarkable manner with free hydroxylamine. crystals of iodine dissolve instantly in contact with it, with evolution of a gas and considerable rise of temperature. bromine reacts with violence, a gas again being explosively evolved and hydrobromic acid formed. the nature of the gas evolved is now undergoing investigation. a letter from m. lobry de bruyn appears in the number of the _chemiker zeitung_ for october , warning those who may attempt to prepare free hydroxylamine by the above method that it is a dangerously explosive substance when warmed to a temperature of °- °. upon warming a flask containing the free solid base upon a water bath a most violent explosion occurs. a spontaneous decomposition appears to set in about °, and even in open vessels the explosion is very violent. care must also be taken during the fractional distillation of the concentrated solution in methyl alcohol to cool the apparatus before changing the receiver, as if air is admitted while the retort is heated the experiment ends with an explosion.--_nature_. * * * * * the scientific american architects and builders edition $ . a year. single copies, cts. this is a special edition of the scientific american, issued monthly--on the first day of the month. each number contains about forty large quarto pages, equal to about two hundred ordinary 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[illustration] scientific american supplement no. new york, october , . scientific american supplement. vol. xxiv., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. biography.--dr. morell mackenzie.--biographical note and portrait of the great english laryngologist--the physician of the prussian crown prince.-- illustration. ii. botany.--soudan coffee.--the _parkia biglobosa_.--its properties and appearance, with analyses of its beans.-- illustrations. wisconsin cranberry culture.--the great cranberry crop of wisconsin.--the indian pickers and details of the cultivation. iii. chemistry.--analysis of kola nut.--a new article adapted as a substitute for cocoa and chocolate to military and other dietaries.--its use by the french and german governments. carbonic acid in the air.--by thomas c. van nuys and benjamin f. adams, jr.--the results of eighteen analyses of air by van nuys apparatus. the crimson line of phosphorescent alumina.--note on prof. crooke's recent investigation of the anomalies of the oxide of aluminum as regards its spectrum. iv. electricity.--electric time.--by m. littmann.--an abstruse research into a natural electric standard of time.--the results and necessary formulæ. new method of maintaining the vibration of a pendulum.--ingenious magneto-electric method of maintaining the swinging of a pendulum. the part that electricity plays in crystallization.--c. decharme's investigations into this much debated question.--the results of his work described.-- illustrations. v. engineering.--a new type of railway car.--a car with lateral passageways, adapted for use in africa-- illustrations. centrifugal pumps at mare island navy yard, california.--by h.r. cornelius.--the great pumps for the mare island dry docks.--their capacity and practical working. foundations of the central viaduct of cleveland, o.--details of the foundations of this viaduct, probably the largest of its kind ever constructed. vi. metallurgy.--chapin wrought iron.--by w.h. searles.--an interesting account of the combined pneumatic and mechanical treatment of pig iron, giving as product a true wrought iron. vii. meteorology.--on the cause of iridescence in clouds.--by g. johnstone stoney.--an interesting theory of the production of prismatic colors in clouds, referring it to interference of light. the height of summer clouds.--a compendious statement, giving the most reliable estimation of the elevations of different forms of clouds. viii. miscellaneous.--the british association.--portraits of the president and section presidents of the late manchester meeting of the british association for the advancement of science, with report of the address of the president, sir henry e. roscoe.-- illustrations. ix. physiology.--hypnotism in france.--a valuable review of the present status of this subject, now so much studied in paris. the duodenum a siphon trap.--by mayo collier, m.s., etc.--a curious observation in anatomy.--the only trap found in the intestinal canal.--its uses.-- illustrations. x. technology.--apparatus for testing champagne bottles and corks.--ingenious apparatus due to mr. j. salleron, for use especially in the champagne industry.-- illustrations. celluloid.--notes of the history and present method of manufacture of this widely used substance. centrifugal extractors.--by robert f. gibson.--the second installment of this extensive and important paper, giving many additional forms of centrifugal apparatus-- illustrations. cotton industries of japan.--an interesting account of the primitive methods of treating cotton by the japanese.--their methods of ginning, carding, etc., described. gas from oil.--notes on a paper read by dr. stevenson macadam at a recent meeting of the british gas institute, giving his results with petroleum gas. improved biscuit machine.--a machine having a capacity for making , small biscuits per minute.-- illustration. improved cream separator.--a centrifugal apparatus for dairy use of high capacity.-- illustrations. the manufacture of salt near middlesbrough.--by sir lowthian bell, bart., f.c.s.--the history and origin of this industry, the methods used, and the soda ash process as there applied. * * * * * the british association. [illustration: the british association at manchester portraits of the president and presidents of sections ] the fifty-seventh annual meeting of the british association was opened on wednesday evening, aug. , , at manchester, by an address from the president, sir h.e. roscoe, m.p. this was delivered in the free trade hall. the chair was occupied by professor williamson, who was supported by the bishop of manchester, sir f. bramwell, professor gamgee, professor milnes marshall, professor wilkins, professor boyd dawkins, professor ward, and many other distinguished men. a telegram was read from the retiring president, sir wm. dawson, of montreal, congratulating the association and manchester on this year's meeting. the new president, sir h. roscoe, having been introduced to the audience, was heartily applauded. the president, in his inaugural address, said manchester, distinguished as the birthplace of two of the greatest discoveries of modern science, welcomed the visit of the british association for the third time. those discoveries were the atomic theory of which john dalton was the author, and the most far-reaching scientific principle of modern times, namely, that of the conservation of energy, which was given to the world about the year by dr. joule. while the place suggested these reminders, the time, the year of the queen's jubilee, excited a feeling of thankfulness that they had lived in an age which had witnessed an advance in our knowledge of nature and a consequent improvement in the physical, moral, and intellectual well-being of the people hitherto unknown. progress of chemistry. a sketch of that progress in the science of chemistry alone would be the subject of his address. the initial point was the views of dalton and his contemporaries compared with the ideas which now prevail; and he (the president) examined this comparison by the light which the research of the last fifty years had thrown on the subject of the daltonian atoms, in the three-fold aspect of their size, indivisibility, and mutual relationships, and their motions. size of the atom. as to the size of the atom, loschmidt, of vienna, had come to the conclusion that the diameter of an atom of oxygen or nitrogen was the ten-millionth part of a centimeter. with the highest known magnifying power we could distinguish the forty-thousandth part of a centimeter. if, now, we imagine a cubic box each of whose sides had this length, such a box, when filled with air, would contain from sixty to a hundred millions of atoms of oxygen and nitrogen. as to the indivisibility of the atom, the space of fifty years had completely changed the face of the inquiry. not only had the number of distinct, well-established elementary bodies increased from fifty-three in to seventy in , but the properties of these elements had been studied, and were now known with a degree of precision then undreamt of. had the atoms of our present elements been made to yield? to this a negative answer must undoubtedly be given, for even the highest of terrestrial temperatures, that of the electric spark, had failed to shake any one of these atoms in two. this was shown by the results with which spectrum analysis had enriched our knowledge. terrestrial analysis had failed to furnish favorable evidence; and, turning to the chemistry of the stars, the spectra of the white, which were presumably the hottest stars, furnished no direct evidence that a decomposition of any terrestrial atom had taken place; indeed, we learned that the hydrogen atom, as we know it here, can endure unscathed the inconceivably fierce temperature of stars presumably many times more fervent than our sun, as sirius and vega. it was therefore no matter for surprise if the earth-bound chemist should for the present continue to regard the elements as the unalterable foundation stones upon which his science is based. atomic motion. passing to the consideration of atoms in motion, while dalton and graham indicated that they were in a continual state of motion, we were indebted to joule for the first accurate determination of the rate of that motion. clerk-maxwell had calculated that a hydrogen molecule, moving at the rate of seventy miles per minute, must, in one second of time, knock against others no fewer than eighteen thousand million times. this led to the reflection that in nature there is no such thing as great or small, and that the structure of the smallest particle, invisible even to our most searching vision, may be as complicated as that of any one of the heavenly bodies which circle round our sun. how did this wonderful atomic motion affect their chemistry? atomic combination. lavoisier left unexplained the dynamics of combustion; but in , before the chemical section of the association meeting at cork, dr. joule announced the discovery which was to revolutionize modern science, namely, the determination of the mechanical equivalent of heat. every change in the arrangement of the particles he found was accompanied by a definite evolution or an absorption of heat. heat was evolved by the clashing of the atoms, and this amount was fixed and definite. thus to joule we owe the foundation of chemical dynamics and the basis of thermal chemistry. it was upon a knowledge of the mode of arrangement of atoms, and on a recognition of their distinctive properties, that the superstructure of modern organic chemistry rested. we now assumed on good grounds that the atom of each element possessed distinct capabilities of combination. the knowledge of the mode in which the atoms in the molecule are arranged had given to organic chemistry an impetus which had overcome many experimental obstacles, and organic chemistry had now become synthetic. liebig and wohler, in , foresaw the artificial production in the laboratories of all organic substances so far as they did not constitute a living organism. and after fifty years their prophecy had been fulfilled, for at the present time we could prepare an artificial sweetening principle, an artificial alkaloid, and salacine. synthesis. we know now that the same laws regulate the formation of chemical compounds in both animate and inanimate nature, and the chemist only asked for a knowledge of the constitution of any definite chemical compounds found in the organic world in order to be able to promise to prepare it artificially. seventeen years elapsed between wohler's discovery of the artificial production of urea and the next real synthesis, which was accomplished by kolbe, when in he prepared acetic acid from its elements. since then a splendid harvest of results had been gathered in by chemists of all nations. in dumas made known the law of substitution, and showed that an exchange could take place between the constituent atoms in a molecule, and upon this law depended in great measure the astounding progress made in the wide field of organic synthesis. perhaps the most remarkable result had been the production of an artificial sweetening agent, termed saccharin, times sweeter than sugar, prepared by a complicated series of reactions from coal tar. these discoveries were not only of scientific interest, for they had given rise to the industry of coal tar colors, founded by our countryman perkin, the value of which was measured by millions sterling annually. another interesting application of synthetic chemistry to the needs of everyday life was the discovery of a series of valuable febrifuges, of which antipyrin might be named as the most useful. an important aspect in connection with the study of these bodies was the physiological value which had been found to attach to the introduction of certain organic radicals, so that an indication was given of the possibility of preparing a compound which will possess certain desired physiological properties, or even to foretell the kind of action which such bodies may exert on the animal economy. but now the question might well be put, was any limit set to this synthetic power of the chemist? although the danger of dogmatizing as to the progress of science had already been shown in too many instances, yet one could not help feeling that the barrier between the organized and unorganized worlds was one which the chemist at present saw no chance of breaking down. true, there were those who professed to foresee that the day would arrive when the chemist, by a succession of constructive efforts, might pass beyond albumen, and gather the elements of lifeless matter into a living structure. whatever might be said regarding this from other standpoints, the chemist could only say that at present no such problem lay within his province. protoplasm, with which the simplest manifestations of life are associated, was not a compound, but a structure built up of compounds. the chemist might successfully synthesize any of its component molecules, but he had no more reason to look forward to the synthetic production of the structure than to imagine that the synthesis of gallic acid led to the artificial production of gall nuts. although there was thus no prospect of effecting a synthesis of organized material, yet the progress made in our knowledge of the chemistry of life during the last fifty years had been very great, so much so indeed that the sciences of physiological and of pathological chemistry might be said to have entirely arisen within that period. chemistry of vital functions. he would now briefly trace a few of the more important steps which had marked the recent study of the relations between the vital phenomena and those of the inorganic world. no portion of the science of chemistry was of greater interest or greater complexity than that which, bearing on the vital functions both of plants and of animals, endeavored to unravel the tangled skein of the chemistry of life, and to explain the principles according to which our bodies live, and move, and have their being. if, therefore, in the less complicated problems with which other portions of our science have to deal, we found ourselves often far from possessing satisfactory solutions, we could not be surprised to learn that with regard to the chemistry of the living body--whether vegetable or animal--in health or disease, we were still farther from a complete knowledge of phenomena, even those of fundamental importance. liebig asked if we could distinguish, on the one hand, between the kind of food which goes to create warmth and, on the other, that by the oxidation of which the motions and mechanical energy of the body are kept up. he thought he was able to do this, and he divided food into two categories. the starchy or carbo-hydrate food was that, said he, which by its combustion provided the warmth necessary for the existence and life of the body. the albuminous or nitrogenous constituents of our food, the flesh meat, the gluten, the casein out of which our muscles are built up, were not available for the purpose of creating warmth, but it was by the waste of those muscles that the mechanical energy, the activity, the motions of the animal are supplied. soon after the promulgation of these views, j.r. mayer warmly attacked them, throwing out the hypothesis that all muscular action is due to the combustion of food, and not to the destruction of muscle. what did modern research say to this question? could it be brought to the crucial test of experiment? it could; but how? in the first place, we could ascertain the work done by a man or any other animal; we could measure this work in terms of our mechanical standard, in kilogramme-meters or foot-pounds. we could next determine what was the destruction of nitrogenous tissue at rest and under exercise by the amount of nitrogenous material thrown off by the body. and here we must remember that these tissues were never completely burned, so that free nitrogen was never eliminated. if now we knew the heat value of the burned muscle, it was easy to convert this into its mechanical equivalent and thus measure the energy generated. what was the result? was the weight of muscle destroyed by ascending the faulhorn or by working on the treadmill sufficient to produce on combustion heat enough when transformed into mechanical exercise to lift the body up to the summit of the faulhorn or to do the work on the treadmill? careful experiment had shown that this was so far from being the case that the actual energy developed was twice as great as that which could possibly be produced by the oxidation of the nitrogenous constituents eliminated from the body during twenty-four hours. that was to say, taking the amount of nitrogenous substance cast off from the body, not only while the work was being done, but during twenty-four hours, the mechanical effect capable of being produced by the muscular tissue from which this cast-off material was derived would only raise the body half way up the faulhorn, or enable the prisoner to work half his time on the treadmill. hence it was clear that liebig's proposition was not true. the nitrogenous constituents of the food did doubtless go to repair the waste of muscle, which, like every other portion of the body, needed renewal, while the function of the non-nitrogenous food was not only to supply the animal heat, but also to furnish, by its oxidation, the muscular energy of the body. we thus came to the conclusion that it was the potential energy of the food which furnished the actual energy of the body, expressed in terms either of heat or of mechanical work. but there was one other factor which came into play in this question of mechanical energy, and must be taken into account; and this factor we were as yet unable to estimate in our usual terms. it concerned the action of the mind on the body, and although incapable of exact expression, exerted none the less an important influence on the physics and chemistry of the body, so that a connection undoubtedly existed between intellectual activity or mental work and bodily nutrition. what was the expenditure of mechanical energy which accompanied mental effort was a question which science was probably far from answering; but that the body experienced exhaustion as the result of mental activity was a well-recognized fact. chemistry of vegetation. the phenomena of vegetation, no less than those of the animal world, had, however, during the last fifty years been placed by the chemist on an entirely new basis. liebig, in , asserted that the whole of the carbon of vegetation was obtained from the atmospheric carbonic acid, which, though only present in the small relative proportion of four parts in , of air, was contained in such absolutely large quantity that if all the vegetation on the earth's surface were burned, the proportion of carbonic acid which would thus be thrown into the air would not be sufficient to double the present amount. that this conclusion was correct needed experimental proof, but such proof could only be given by long-continued and laborious experiment. it was to our english agricultural chemists, lawes and gilbert, that we owed the complete experimental proof required, and this experiment was long and tedious, for it had taken forty-four years to give a definite reply. at rothamsted a plot was set apart for the growth of wheat. for forty-four successive years that field had grown wheat without the addition of any carbonized manure, so that the only possible source from which the plant could obtain the carbon for its growth was the atmospheric carbonic acid. the quantity of carbon which on an average was removed in the form of wheat and straw from a plot manured only with mineral matter was , lb., while on another plot, for which a nitrogenous manure was employed, , lb. more carbon was annually removed, or , lb. of carbon were removed by this crop annually without the addition of any carbonaceous manure. so that liebig's prevision had received a complete experimental verification. chemical pathology. touching us as human beings even still more closely than the foregoing was the influence which chemistry had exerted on the science of pathology, and in no direction had greater progress been made than in the study of micro-organisms in relation to health and disease. in the complicated chemical changes to which we gave the names of fermentation and putrefaction, pasteur had established the fundamental principle that these processes were inseparately connected with the life of certain low forms of organisms. thus was founded the science of bacteriology, which in lister's hands had yielded such splendid results in the treatment of surgical cases, and in those of klebs, koch, and others, had been the means of detecting the cause of many diseases both in man and animals, the latest and not the least important of which was the remarkable series of successful researches by pasteur into the nature and mode of cure of that most dreadful of maladies, hydrophobia. the value of his discovery was greater than could be estimated by its present utility, for it showed that it might be possible to avert other diseases besides hydrophobia by the adoption of a somewhat similar method of investigation and of treatment. here it might seem as if we had outstepped the boundaries of chemistry, and had to do with phenomena purely vital. but recent research indicated that this was not the case, and pointed to the conclusion that the microscopist must again give way to the chemist, and that it was by chemical rather than biological investigation that the causes of diseases would be discovered, and the power of removing them obtained. for we learned that the symptoms of infective diseases were no more due to the microbes which constituted the infection than alcoholic intoxication was produced by the yeast cell, but that these symptoms were due to the presence of definite chemical compounds, the result of the life of these microscopic organisms. so it was to the action of these poisonous substances formed during the life of the organism, rather than to that of the organism itself, that the special characteristics of the disease were to be traced, for it had been shown that the disease could be communicated by such poisons in the entire absence of living organisms. had time permitted, he would have wished to have illustrated the dependence of industrial success upon original investigation, and to have pointed out the prodigious strides which chemical industry in this country had made during the fifty years of her majesty's reign. as it was, he must be content to remark how much our modern life, both in its artistic and useful aspects, owed to chemistry, and therefore how essential a knowledge of the principles of the science was to all who had the industrial progress of the country at heart. the country was now beginning to see that if she was to maintain her commercial and industrial supremacy, the education of her people from top to bottom must be carried out on new lines. the question how this could be most safely and surely accomplished was one of transcendent national importance, and the statesman who solved this educational problem would earn the gratitude of generations yet to come. in welcoming the unprecedentedly large number of foreign men of science who had on this occasion honored the british association by their presence, he hoped that that meeting might be the commencement of an international scientific organization, the only means nowadays existing of establishing that fraternity among nations from which politics appeared to remove them further and further, by absorbing human powers and human work, and directing them to purposes of destruction. it would indeed be well if great britain, which had hitherto taken the lead in so many things that are great and good, should now direct her attention to the furthering of international organizations of a scientific nature. a more appropriate occasion than the present meeting could perhaps hardly be found for the inauguration of such a movement. but whether this hope were realized or not, they all united in that one great object, the search after truth for its own sake, and they all, therefore, might join in re-echoing the words of lessing: "the worth of man lies not in the truth which he possesses, or believes that he possesses, but in the honest endeavor which he puts forth to secure that truth; for not by the possession of truth, but by the search after it, are the faculties of man enlarged, and in this alone consists his ever-growing perfection. possession fosters content, indolence, and pride. if god should hold in his right hand all truth, and in his left hand the ever-active desire to seek truth, though with the condition of perpetual error, i would humbly ask for the contents of the left hand, saying, 'father, give me this; pure truth is only for thee.'" at the close of his address a vote of thanks was passed to the president, on the motion of the mayor of manchester, seconded by professor asa gray, of harvard college. the president mentioned that the number of members is already larger than at any previous annual meeting, namely, , , including eighty foreigners. * * * * * the crimson line of phosphorescent alumina. crookes has presented to the royal society a paper on the color emitted by pure alumina when submitted to the electric discharge _in vacuo_, in answer to the statements of de boisbaudran. in he had stated that "next to the diamond, alumina, in the form of ruby, is perhaps the most strikingly phosphorescent stone i have examined. it glows with a rich, full red; and a remarkable feature is that it is of little consequence what degree of color the earth or stone possesses naturally, the color of the phosphorescence is nearly the same in all cases; chemically precipitated amorphous alumina, rubies of a pale reddish yellow, and gems of the prized 'pigeon's blood' color glowing alike in the vacuum." these results, as well as the spectra obtained, he stated further, corroborated becquerel's observations. in consequence of the opposite results obtained by de boisbaudran, crookes has now re-examined this question with a view to clear up the mystery. on examining a specimen of alumina prepared from tolerably pure aluminum sulphate, shown by the ordinary tests to be free from chromium, the bright crimson line, to which the red phosphorescent light is due, was brightly visible in its spectrum. the aluminum sulphate was then, in separate portions, purified by various processes especially adapted to separate from it any chromium that might be present; the best of these being that given by wohler, solution in excess of potassium hydrate and precipitation of the alumina by a current of chlorine. the alumina filtered off, ignited, and tested in a radiant matter tube gave as good a crimson line spectrum as did that from the original sulphate. a repetition of this purifying process gave no change in the result. four possible explanations are offered of the phenomena observed: "( ) the crimson line is due to alumina, but it is capable of being suppressed by an accompanying earth which concentrates toward one end of the fractionations; ( ) the crimson line is not due to alumina, but is due to the presence of an accompanying earth concentrating toward the other end of the fractionations; ( ) the crimson line belongs to alumina, but its full development requires certain precautions to be observed in the time and intensity of ignition, degree of exhaustion, or its absolute freedom from alkaline and other bodies carried down by precipitated alumina and difficult to remove by washing; experience not having yet shown which of these precautions are essential to the full development of the crimson line and which are unessential; and ( ) the earth alumina is a compound molecule, one of its constituent molecules giving the crimson line. according to this hypothesis, alumina would be analogous to yttria."--_nature._ * * * * * carbonic acid in the air. by thomas c. van nuys and benjamin f. adams, jr. during the month of april, , we made eighteen estimations of carbonic acid in the air, employing van nuys' apparatus,[ ] recently described in this journal. these estimations were made in the university park, one-half mile from the town of bloomington. the park is hilly, thinly shaded, and higher than the surrounding country. the formation is sub-carboniferous and altitude meters. there are no lowlands or swamps near. the estimations were made at a.m. [footnote : see sci. am. supplement no. .] the air was obtained one-half meter from the ground and about meters from any of the university buildings. the number of volumes of carbonic acid is calculated at zero c. and normal pressure mm. --------+----------+--------------+------------------------ | | vols. co_{ } | date. | bar. | in , | state of weather. | pressure | vols. air. | --------+----------+--------------+------------------------ april | . | . | cloudy, snow on ground. " | . | . | " " " " " | | . | snowing. " | . | . | clear, snow on ground. " | | . | " thawing. " | . | . | " " " | | . | cloudy. " | | . | clear. " | . | . | " " | . | . | raining. " | | . | clear. " | | . | " " | | . | " " | . | . | " " | | . | " " | . | . | " " | . | . | " " | | . | " --------+----------+--------------+------------------------ the average number of volumes of carbonic acid in , volumes of air is . , the maximum number is . , and the minimum . . these results agree with estimations made within the last ten or fifteen years. reiset[ ] made a great number of estimations from september , , to august , , the average of which is . . six years later[ ] he made many estimations from june to november, the average of which is . . the average of schultze's[ ] estimations is . the results of estimations of carbonic acid in the air, made under the supervision of munz and aubin[ ] in october, november, and december, , at the stations where observations were made of the transit of venus by astronomers sent out by the french government, yield the average, for all stations north of the equator to latitude ° ' in florida, . volumes carbonic acid in , volumes air, and for all stations south of the equator . volumes. the average of claesson's[ ] estimations is . volumes, his maximum number is . , and his minimum is . . it is apparent, from the results of estimations of carbonic acid of the air of various parts of the globe, by the employment of apparatus with which errors are avoided, that the quantity of carbonic acid is subject to slight variation, and not, as stated in nearly all text books of science, from to volumes in , volumes of air; and it is further apparent that the law of schloesing[ ] holds good. by this law the carbonic acid of an atmosphere in contact with water containing calcium or magnesium carbonate in solution is dissolved according to the tension of the carbonic acid; that is, by an increased quantity its tension increases, and more would pass in solution in the form of bicarbonates. on the other hand, by diminishing the quantity of carbonic acid in the atmosphere, some of the bicarbonates would decompose and carbonic acid pass into the atmosphere. [footnote : comptes rendus, , .] [footnote : comptes rendus, , .] [footnote : chem. centralblatt, and .] [footnote : comptes rendus, , .] [footnote : berichte der deutsch chem. gesellschaft, , .] [footnote : comptes rendus, , , and , .] schloesing's law has been verified by r. engel[ ]. [footnote : comptes rendus, , .] the results of estimations of bases and carbonic acid in the water of the english channel lead schloesing[ ] to conclude that the carbonic acid combined with normal carbonates, forming bicarbonates, dissolved in the water of the globe is ten times greater in quantity than that of the atmosphere, and on account of this available carbonic acid, if the atmosphere should be deprived of some of its carbonic acid, the loss would soon be supplied. [footnote : comptes rendus, , .] as, in nearly all of the methods which were employed for estimating carbonic acid in the air, provision is not made for the exclusion of air not measured containing carbonic acid from the alkaline fluid before titrating or weighing, the results are generally too high and show a far greater variation than is found by more exact methods. for example, gilm[ ] found from to volumes; levy's[ ] average is volumes; de luna's[ ] volumes; and fodor's,[ ] . volumes. admitting that the quantity of carbonic acid in the air is subject to variation, yet the results of reiset's and schultze's estimations go to prove that the variation is within narrow limits. [footnote : sitzungsher. d. wien. akad. d. wissenschaften, , .] [footnote : ann. d. l'observ. d. mountsouris, and .] [footnote : estudios quimicos sobre el aire atmosferico, madrid, .] [footnote : hygien. untersuch., , .] indiana university chemical laboratory, bloomington, indiana. --_amer. chem. journal._ * * * * * analysis of kola nut. alkaloids or crystallizable principles: per cent. caffeine. . theobromine. . bitter principle. . total alkaloids. ----- . fatty matters: saponifiable fat or oil. . essential oil. . total oils. ----- . resinoid matter (_sol. in abs. alcohol_) . sugar: glucose (_reduces alkaline cuprammonium_). . sucrose? (_red. alk. cupram. after inversion_)[ ]. . total sugars. ----- . starch, gum, etc.: gum (_soluble in h o at ° f_.). . starch. . amidinous matter (_coloring with iodine_). . total gum and fecula. ----- . albuminoid matters. . red and other coloring matters. . kolatannic acids. . mineral matter: potassa. . chlorine. . phosphoric acid. . other salts, etc. . total ash. ----- . moisture. . ligneous matter and loss. . ------- . [footnote : inverted by boiling with a . per cent. solution of citric acid for ten minutes.] both the french and german governments are introducing it into their military dietaries, and in england several large contract orders cannot yet be filled, owing to insufficiency of supply, while a well-known cocoa manufacturing firm has taken up the preparation of kola chocolate upon a commercial scale.--_w. lascelles-scott, in jour. soc. arts._ * * * * * chapin wrought iron. by w.h. searles, chairman of the committee, civil engineers' club of cleveland, o. notwithstanding the wonderful development of our steel industries in the last decade, the improvements in the modes of manufacture, and the undoubted strength of the metal under certain circumstances, nevertheless we find that steel has not altogether met the requirements of engineers as a structural material. although its breaking strain and elastic limit are higher than those of wrought iron, the latter metal is frequently preferred and selected for tensile members, even when steel is used under compression in the same structure. the niagara cantilever bridge is a notable instance of this practice. when steel is used in tension its working strains are not allowed to be over fifty per cent. above those adopted for wrought iron. the reasons for the suspicion with which steel is regarded are well understood. not only is there a lack of uniformity in the product, but apparently the same steel will manifest very different results under slight provocation. steel is very sensitive, not only to slight changes in chemical composition, but also to mechanical treatment, such as straightening, bending, punching, planing, heating, etc. initial strains may be developed by any of these processes that would seriously affect the efficiency of the metal in service. among the steels, those that are softer are more serviceable and reliable than the harder ones, especially whereever shocks and concussions or rapidly alternating strains are to be endured. in other words, the more nearly steel resembles good wrought iron, the more certain it is to render lasting service when used within appropriate limits of strain. indeed, a wrought iron of fine quality is better calculated to endure fatigue than any steel. this is particularly noticeable in steam hammer pistons, propeller shafts, and railroad axles. a better quality of wrought iron, therefore, has long been a desideratum, and it appears now that it has at last been found. several years since, a pneumatic process of manufacturing wrought iron was invented and patented by dr. chapin, and an experimental plant was erected near chicago. enough was done to demonstrate, first, that an iron of unprecedentedly good qualities was attainable from common pig; and second, that the cost of its manufacture would not exceed that of bessemer steel. nevertheless, owing to lack of funds properly to push the invention against the jealous opposition which it encountered, the enterprise came to a halt until quite recently, when its merits found a champion in gustav lindenthal, c.e., member of this club, who is now the general manager of the chapin pneumatic iron co., and under whose direction this new quality of iron will soon be put upon the market. the process of manufacture is briefly as follows: the pig metal, after being melted in a cupola and tapped into a discharging ladle, is delivered into a bessemer converter, in which the metal is largely relieved of its silicon, sulphur, carbon, etc., by the ordinary pneumatic process. at the end of the blow the converter is turned down and its contents discharged into a traveling ladle, and quickly delivered to machines called ballers, which are rotary reverberatory furnaces, each revolving on a horizontal axis. in the baller the iron is very soon made into a ball without manual aid. it is then lifted out by means of a suspended fork and carried to a winslow squeezer, where the ball is reduced to a roll twelve inches in diameter. thence it is taken to a furnace for a wash heat, and finally to the muck train. no reagents are employed, as in steel making or ordinary iron puddling. the high heat of the metal is sufficient to preserve its fluidity during its transit from the converter to the baller; and the cinder from the blow is kept in the ladle. the baller is a bulging cylinder having hollow trunnions through which the flame passes. the cylinder is lined with fire brick, and this in turn is covered with a suitable refractory iron ore, from eight to ten inches thick, grouted with pulverized iron ore, forming a bottom, as in the common puddling furnace. the phosphorus of the iron, which cannot be eliminated in the intense heat of the converter, is, however, reduced to a minimum in the baller at a much lower temperature and on the basic lining. the process wastes the lining very slightly indeed. as many as sixty heats have been taken off in succession without giving the lining any attention. the absence of any reagent leaves the iron simply pure and homogeneous to a degree never realized in muck bars made by the old puddling process. thus the expense of a reheating and rerolling to refine the iron is obviated. it was such iron as here results that bessemer, in his early experiments, was seeking to obtain when he was diverted from his purpose by his splendid discoveries in the art of making steel. so effective is the new process, that even from the poorest grades of pig may be obtained economically an iron equal in quality to the refined irons made from the best pig by the ordinary process of puddling. numerous tests of the chapin irons have been made by competent and disinterested parties, and the results published. the samples here noted were cut and piled only once from the muck bar. sample a was made from no. mill cinder pig. sample b was made from no. mill pig and no. bessemer pig, half and half. sample c was made from no. bessemer pig, with the following results: sample. a b c tensile strength per sq. in. , , , elastic limit. , .... , extension, per cent. . .... . reduction of area, per cent. . . . the tensile strength of these irons made by ordinary puddling would be about , , , , and , respectively, or the gain of the iron in tensile strength by the chapin process is about fifty per cent. not only so, but these irons made in this manner from inferior pig show a higher elastic limit and breaking strain than are commonly specified for refined iron of best quality. the usual specifications are for refined iron: tensile strength, , ; elongation, per cent.; elastic limit, , ; reduction, cent. thus the limits of the chapin iron are from to per cent. above those of refined iron, and not far below those of structural steel, while there is a saving of some four dollars per ton in the price of the pig iron from which it can be made. when made from the best pig metal its breaking and elastic limits will probably reach , and , pounds respectively. if so, it will be a safer material than steel under the same working strains, owing to its greater resilience. such results are very interesting in both a mechanical and economical point of view. engineers will hail with delight the accession to the list of available building materials of a wrought iron at once fine, fibrous, homogeneous, ductile, easily weldable, not subject to injury by the ordinary processes of shaping, punching, etc., and having a tensile strength and elastic limit nearly equal to any steel that could safely be used in the same situation. a plant for the manufacture of chapin iron is now in course of erection at bethlehem, pa., and there is every reason to believe that the excellent results attained in chicago will be more than reached in the new works.--_proceed. jour. asso. of eng. societies_. * * * * * celluloid. professor sadler, of the university of pennsylvania, has lately given an account of the development and method of the manufacture of celluloid. alexander parkes, an englishman, invented this remarkable substance in , but after twelve years quit making it because of difficulties in manipulation, although he made a fine display at the paris exposition of . daniel spill, also of england, began experiments two years after parkes, but a patent of his for dissolving the nitrated wood fiber, or "pyroxyline," in alcohol and camphor was decided by judge blatchford in a suit brought against the celluloid manufacturing company to be valueless. no further progress was made until the hyatt brothers, of albany, n.y., discovered that gum camphor, when finely divided, mixed with the nitrated fiber and then heated, is a perfect solvent, giving a homogeneous and plastic mass. american patents of and are substantially identical with those now in use in england. in france there is only one factory, and there is none elsewhere on the continent, one in hanover having been given up on account of the explosive nature of the stuff. in this country pure cellulose is commonly obtained from paper makers, in the form of tissue paper, in wide rolls; this, after being nitrated by a bath of mixed nitric and sulphuric acids, is thoroughly washed and partially dried. camphor is then added, and the whole is ground together and thoroughly mixed. at this stage coloring matter may be put in. a little alcohol increases the plasticity of the mass, which is then treated for some time to powerful hydraulic pressure. then comes breaking up the cakes and feeding the fragments between heated rolls, by which the amalgamation of the whole is completed. its perfect plasticity allows it to be rolled into sheets, drawn into tubes, or moulded into any desired shape.--_jewelers' journal._ * * * * * apparatus for testing champagne bottles and corks. mr. j. salleron has devised several apparatus which are destined to render valuable service in the champagne industry. the apparently simple operation of confining the carbonic acid due to fermentation in a bottle in order to blow the cork from the latter with force at a given moment is not always successful, notwithstanding the skill and experience of the manipulator. how could it be otherwise? everything connected with the production of champagne wine was but recently unknown and unexplained. the proportioning of the sugar accurately dates, as it were, from but yesterday, and the measurement of the absorbing power of wine for carbonic acid has but just entered into practice, thanks to mr. salleron's absorptiometer. the real strength of the bottles, and the laws of the elasticity of glass and its variation with the temperature, are but little known. finally, the physical constitution of cork, its chemical composition, its resistance to compression and the dissolving action of the wine, must be taken into consideration. in fact, all the elements of the difficult problem of the manufacture of sparkling wine show that there is an urgent necessity of introducing scientific methods into this industry, as without them work can now no longer be done. no one has had a better opportunity to show how easy it is to convert the juice of the grape into sparkling wine through a series of simple operations whose details are known and accurately determined, so we believe it our duty to recommend those of our readers who are particularly interested in this subject to read mr. salleron's book on sparkling wine. we shall confine ourselves in this article to a description of two of the apparatus invented by the author for testing the resistance of bottles and cork stoppers. it is well, in the first place, to say that one of the important elements in the treatment of sparkling wine is the normal pressure that it is to produce in the bottles. after judicious deductions and numerous experiments, mr. salleron has adopted for the normal pressure of highly sparkling wines five atmospheres at the temperature of the cellar, which does not exceed degrees. but, in a defective cellar, the bottles may be exposed to frost in winter and to a temperature of ° in summer, corresponding to a tension of ten atmospheres. it may naturally be asked whether bottles will withstand such an ordeal. mr. salleron has determined their resistance through the process by which we estimate that of building materials, viz., by measuring the limit of their elasticity, or, in other words, the pressure under which they take on a new permanent volume. in fact, glass must be assimilated to a perfectly elastic body; and bottles expand under the internal pressure that they support. if their resistance is insufficient, they continue to increase in measure as the pressure is further prolonged, and at every increase in permanent capacity, their resistance diminishes. [illustration: fig. .--machine for testing bottles.] the apparatus shown in fig. is called an elasticimeter, and permits of a preliminary testing of bottles. the bottle to be tested is put into the receptacle, a b, which is kept full of water, and when it has become full, its neck is played between the jaws of the clamp, _p_. upon turning the hand wheel, l, the bottle and the receptacle that holds it are lifted, and the mouth of the bottle presses against a rubber disk fixed under the support, c d. the pressure of the neck of the bottle against this disk is such that the closing is absolutely hermetical. the support, c d, contains an aperture which allows the interior of the bottle to communicate with a glass tube, _a b_, which thus forms a prolongation of the neck of the bottle. this tube is very narrow and is divided into fiftieths of a cubic centimeter. a microscope, _m_, fixed in front of the tube, magnifies the divisions, and allows the position of the level of the water to be ascertained to within about a millionth of a cubic centimeter. a force and suction pump, p, sucks in air through the tube, _t_, and compresses it through the tube, _t'_, in the copper tube, t, which communicates with the glass tube, _a b_, after passing through the pressure gauge, m. this pump, then, compresses the air in the bottle, and the gauge accurately measures its pressure. to make a test, after the bottle full of water has been fastened under the support, c d, the cock, _s_, is opened and the liquid with which the small reservoir, r, has been filled flows through an aperture above the mouth of the bottle and rises in the tube, _a b_. when its level reaches the division, o, the cock, _s_, is closed. the bottle and its prolongation, _a b_, are now exactly full of water without any air bubbles. the pump is actuated, and, in measure as the pressure rises, the level of the liquid in the tube, _a b_, is seen to descend. this descent measures the expansion or flexion of the bottle as well as the compression of the water itself. when the pressure is judged to be sufficient, the button, _n_, is turned, and the air compressed by the pump finding an exit, the needle of the pressure gauge will be seen to redescend and the level of the tube, _a b_, to rise. if the glass of the bottle has undergone no permanent deformation, the level will rise exactly to the zero mark, and denote that the bottle has supported the test without any modification of its structure. but if, on the contrary, the level does not return to the zero mark, the limit of the glass's elasticity has been extended, its molecules have taken on a new state of equilibrium, and its resistance has diminished, and, even if it has not broken, it is absolutely certain that it has lost its former resistance and that it presents no particular guarantee of strength. the vessel, a b, which must be always full of water, is designed to keep the bottle at a constant temperature during the course of the experiment. this is an essential condition, since the bottle thus filled with water constitutes a genuine thermometer, of which _a b_ is the graduated tube. it is therefore necessary to avoid attributing a variation in level due to an expansion of the water produced by a change in temperature, to a deformation of the bottle. the test, then, that can be made with bottles by means of the elasticimeter consists in compressing them to a pressure of ten atmospheres when filled with water at a temperature of °, and in finding out whether, under such a stress, they change their volume permanently. in order that the elasticimeter may not be complicated by a special heating apparatus, it suffices to determine once for all what the pressure is that, at a mean temperature of °, acts upon bottles with the same energy as that of ten atmospheres at °. experiment has demonstrated that such stress corresponds to twelve atmospheres in a space in which the temperature remains about °. in addition, the elasticimeter is capable of giving other and no less useful data. it permits of comparing the resistance of bottles and of classifying them according to the degree of such resistance. after numerous experiments, it has been found that first class bottles easily support a pressure of twelve atmospheres without distortion, while in those of an inferior quality the resistance is very variable. the champagne wine industry should therefore use the former exclusively. various precautions must be taken in the use of corks. the bottles that lose their wine in consequence of the bad quality of their corks are many in number, and it is not long since that they were the cause of genuine disaster to the champagne trade. mr. salleron has largely contributed to the improving of the quality of corks found in the market. the physical and chemical composition of cork bark is peculiarly favorable to the special use to which it is applied; but the champagne wine industry requires of it an exaggerated degree of resistance, inalterability, and elasticity. a ¼ inch cork must, under the action of a powerful machine, enter a ¾ inch neck, support the dissolving action of a liquid containing per cent. of alcohol compressed to at least five atmospheres, and, in a few years, shoot out of the bottle and assume its pristine form and color. out of a hundred corks of good quality, not more than ten support such a test. in order to explain wherein resides the quality of cork, it is necessary to refer to a chemical analysis of it. in cork bark there is per cent. of suberine, which is soluble in alcohol and ether, and is plastic, ductile, and malleable under the action of humid heat. mixed with suberine, cerine and resin give cork its insolubility and inalterability. these substances are soluble in alcohol and ether, but insoluble in water. according to the origin of cork, the wax and resin exist in it in very variable proportion. the more resinous kinds resist the dissolving action of wine better than those that are but slightly resinous. the latter soon become corroded and spoiled by wine. an attempt has often been made, but without success, to improve poor corks by impregnating them with the resinous principle that they lack. various other processes have been tried without success, and so it finally became necessary simply to separate the good from the bad corks by a practical and rapid operation. a simple examination does not suffice. mr. bouché has found that corks immersed in water finally became covered with brown spots, and, by analogy, in order to test corks, he immersed them in water for a fortnight or a month. all those that came out spotted were rejected. under the prolonged action of moisture, the suberine becomes soft, and, if it is not resinous enough, the cells of the external layer of the cork burst, the water enters, and the cork becomes spotted. it was left to mr. salleron to render the method of testing practical. he compresses the cork in a very strong reservoir filled with water under a pressure of from four to five atmospheres. by this means, the but slightly resinous cork is quickly dissolved, so that, after a few hours' immersion, the bad corks come out spotted and channeled as if they had been in the neck of a bottle for six months. on the contrary, good corks resist the operation, and come out of the reservoir as white and firm as they were when they were put into it. [illustration: fig. .--salleron's apparatus for testing corks.] fig. gives a perspective view of mr. salleron's apparatus for testing corks. a reservoir, a b, of tinned copper, capable of holding corks, is provided with a cover firmly held in place by a clamp. into the cover is screwed a pressure gauge, m, which measures the internal pressure of the apparatus. a pump, p, sucks water from a vessel through the tubulure, _t'_, and forces it through the tubulure, _t_, into the reservoir full of corks. after being submitted to a pressure of five atmospheres in this apparatus for a few hours, the corks are verified and then sorted out. in addition to the apparatus here illustrated, there is one of larger dimensions for industrial applications. this differs from the other only in the arrangement of its details, and will hold as many as , corks.--_revue industrielle._ * * * * * improved biscuit machine. the accompanying illustration represents a combined biscuit cutting, scrapping, and panning machine, specially designed for running at high speeds, and so arranged as to allow of the relative movements of the various parts being adjusted while in motion. the cutters or dies, mounted on a cross head working in a vertical guide frame, are operated from the main shaft by eccentrics and vertical connecting rods, as shown. these rods are connected to the lower strap of the eccentric by long guide bolts, on which intermediate spiral springs are mounted, and by this means, although the dies are brought quickly down to the dough, they are suffered to remain in contact therewith, under a gradually increasing pressure, for a sufficient length of time to insure the dough being effectually stamped and completely cut through. [illustration: improved biscuit machine.] further, the springs tend to counteract any tendency to vibration that might be set up by the rapid reciprocation of the cross head, cutters, and their attendant parts. mounted also on the main shaft is one of a pair of reversed cone drums. these, with their accompanying belt and its adjusting gear, worked by a hand wheel and traversing screw, as shown, serve to adjust the speed of the feed rollers, so as to suit the different lengths of the intermediate travel or "skip" of the dough-carrying web. provision is made for taking up the slack of this belt by mounting the spindle of the outer coned drum in bearings adjustable along a circular path struck from the axis of the lower feed roller as a center, thus insuring a uniform engagement between the teeth of the small pinion and those of the spur wheel with which the drum and roller are respectively provided. the webs for carrying forward the dough between the different operations pass round rollers, which are each operated by an adjustable silent clutch feed, in place of the usual ratchet and pawl mechanism. movement is given to each feed by the connecting links shown, to each of which motion is in turn imparted by the bell crank lever placed beside the eccentric. this lever is actuated by a crank pin on the main shaft, working into a block sliding in a slot in the shorter or horizontal arm of the lever, while a similar but adjustable block, sliding in the vertical arm, serves to impart the motion of the lever to the system of connecting links, the adjustable block allowing of a longer or shorter stroke being given to the different feeds, as desired. the scraps are carried over the roller in rear of the cutters, and so to a scrap pan, while the stamped biscuits pass by a lower web into the pans. these pans are carried by two endless chains, provided with pins, which take hold of the pans and carry them along in the proper position. the roller over which these chains pass is operated by a silent clutch, and in order to give an additional motion to the chains when a pan is full, and it is desired to bring the next pan into position, an additional clutch is caused to operate upon the roller. this clutch is kept out of gear with its pulley by means of a projection upon it bearing against a disk slightly greater in diameter than the pulley, and provided with two notches, into which the projection passes when the additional feed is required. the makers, h. edwards & co., liverpool, have run one of these machines easily and smoothly at a hundred revolutions per minute, at which speed, and when absorbing about . horse power, the output would equal , small biscuits per minute.--_industries._ * * * * * improved cream separator. a hand separator of this type was exhibited at the royal show at newcastle by the aylesbury dairy company, of st. petersburg place, bayswater, england. [illustration: improved cream separator. fig. .] [illustration: improved cream separator. fig. .] fig. is a perspective view of the machine, fig. being a vertical section. the drums of these machines, which make , revolutions per minute for the large and , for the small one, have a diameter of in. and ½ in. respectively, and are capable of extracting the cream from and gallons of milk per hour. these drums are formed by hydraulic pressure from one piece of sheet steel. to avoid the possibility of the machines being overdriven, which might happen through the negligence of the attendant or through the governing gear on the engine failing to act, an ingenious controlling apparatus is fixed to the intermediate motion of the separator as shown in fig. . this apparatus consists of a pair of governor balls pivoted near the center of the arms and attached to the main shaft of the intermediate gear by means of a collar fixed on it. the main shaft is bored out sufficiently deep to admit a steel rod, against which bear the three ends of the governor arms. the steel rod presses against the counterbalance, which is made exactly the right weight to withstand the force tending to raise it, when the intermediate motion is running at its designed speed. the forks between which the belt runs are also provided with a balance weight. this brings them to the loose pulley, unless they are fixed by means of the ratchet. should the number of revolutions of the intermediate increase beyond the correct amount, the extra centrifugal force imparted to the governor balls enables them to overcome the balance weight, and in raising this they raise the arm. this arm striking against the ratchet detent releases the balance weight, and the belt is at once brought on to the loose pulley. [illustration: improved cream separator. fig. .] the steel drum is fitted with an internal ring at the bottom (see fig. ), into which the milk flows, and from which it is delivered, by three apertures, to the periphery of the drum, thus preventing the milk from striking against the cone of the drum, and from mixing with the cream which has already been separated. the upper part of the drum is fitted with an annular flange, about ½ in. from the top, reaching to within one-sixteenth of an inch of the periphery. after the separation of the skim milk from the cream, the former passes behind and above this flange through the aperture, b, and is removed by means of the tube, d, furnished with a steel tip projecting from the cover of the machine into the space between the top of the drum and the annular flange, a similar tube, f, reaching below this flange, removing the cream which collects there. the skim milk tube is provided with a screw regulator, the function of which is to enable cream of any desired consistency to be obtained, varying with the distance between the skim milk and cream points from the center of the drum. another point about these tubes is their use as elevating tubes for the skim, milk and cream, as, owing to the velocity at which the drum is rotating, the products can be delivered by these tubes at a height of or feet above the machine if required, thus enabling scalding and cooling of either to be carried on while the separator is at work, and saving hand labor.--_iron._ * * * * * gas from oil. at the twenty-fourth annual meeting of the gas institute, which was recently held in glasgow, dr. stevenson macadam, f.r.s.e., lecturer on chemistry, edinburgh, submitted the first paper, which was on "gas from oil." he said that during the last seventeen years he had devoted much attention to the photogenic or illuminating values of different qualities of paraffin oils in various lamps, and to the production of permanent illuminating gas from such oils. the earlier experiments were directed to the employment of paraffin oils as oils, and the results proved the great superiority of the paraffin oils as illuminating agents over vegetable and animal oils, alike for lighthouse and ordinary house service. the later trials were mainly concerned with the breaking up of the paraffin oils into permanent illuminating gas. experiments were made at low heats, medium heats, and high heats, which proved that, according to the respective qualities of the paraffin oils employed in the trials, there was more or less tendency at the lower heats to distill oil instead of permanent gas, while at the high heats there was a liability to decarbonize the oil and gas, and to obtain a thin gas of comparatively small illuminating power. when, however, a good cherry red heat was maintained, the oils split up in large proportion into permanent gas of high illuminating quality, accompanied by little tarry matter, and with only a slight amount of separated carbon or deposited soot. the best mode of splitting up the paraffin oils, and the special arrangements of the retort or distilling apparatus, also formed, he said, an extensive inquiry by itself. in one set of trials the oil was distilled into gaseous vapor, and then passed through the retort. in another set of experiments, the oil was run into or allowed to trickle into the retorts, while both modes of introducing the oil were tried in retorts charged with red hot coke and in retorts free from coke. ultimately, it was found that the best results were obtained by the more simple arrangement of employing iron retorts at a good cherry red heat, and running in the oil as a thin stream direct into the retort, so that it quickly impinged upon the red hot metal, and without the intervention of any coke or other matter in the retorts. the paraffin oils employed in the investigations were principally: ( ) crude paraffin oil, being the oil obtained direct from the destructive distillation of shale in retorts; ( ) green paraffin oil, which is yielded by distilling or re-running the crude paraffin oil, and removing the lighter or more inflammable portion by fractional distillation; and ( ) blue paraffin oil, which is obtained by rectifying the twice run oil with sulphuric acid and soda, and distilling off the paraffin spirit, burning oil, and intermediate oil, and freezing out the solid paraffin as paraffin scale. the best practical trials were obtained in pintsch's apparatus and in keith's apparatus. after describing both of these, dr. macadam went on to give in great detail the results obtained in splitting up blue paraffin oil into gas in each apparatus. he then said that these experimental results demonstrated that pintsch's apparatus yielded from the gallon of oil in one case . cubic feet of gas of . candle power, and in the second case . cubic feet of . candle gas, or an average of . cubic feet of . candle power gas. in both cases, the firing of the retorts was moderate, though in the second trial greater care was taken to secure uniformity of heat, and the oil was run in more slowly, so that there was more thorough splitting up of the oil into permanent gas. the gas obtained in the two trials was of high quality, owing to its containing a large percentage of heavy hydrocarbons, of which there were, respectively, . and . per cent., or an average of . per cent., while the sulphureted hydrogen was nothing, and the carbonic acid a mere trace. besides testing the gas on the occasion of the actual trials, he had also examined samples of the gas which he had taken from various cylinders in which the gas had been stored for several months under a pressure of ten atmospheres, and in all cases the gas was found to be practically equal to the quantity mentioned, and hence of a permanent character. by using keith's apparatus the results obtained were generally the same, with the exception that an average of . per cent. of carbonic acid gas and decided proportions of sulphureted hydrogen were found to be present in the gas. dr. macadam devoted some remarks to the consideration of the question as to how far the gas obtained from the paraffin oil represented the light power of the oil itself, and then he proceeded to say that, taking the crude paraffin oil at d. a gallon, and with a specific gravity of (water = , ), or ½ lb. to the gallon, there were gallons to the ton, at a cost of £ s. per ton. the sperm light from the ton of oil as gas being , lb., he reckoned that fully lb. of sperm light were obtained from a pennyworth of the crude oil as gas. then, taking the blue paraffin oil at d. per gallon, and there being gallons to the ton, it was found that the cost of one ton was £ s., and as the sperm light of a ton of that oil as gas was , lb., it was calculated that lb. of sperm light were yielded in the gas from a pennyworth of the blue oil. the very rich character of the oil gas rendered it unsuitable for consumption at ordinary gas jets, though it burned readily and satisfactorily at small burners not larger than no. jets. in practical use it would be advisable to reduce the quality by admixture with thin and feeble gas, or to employ the oil gas simply for enriching inferior gases derived from the more common coals. on the question of dilution, he said that he preferred to use carbonic oxide and hydrogen, and most of the remainder of his paper was devoted to an explanation of the best mode of preparing those gases (water gases). he concluded by saying: the employment of paraffin oil for gas making has advantages in its favor, in the readiness of charging the retorts, as the oil can be run in continuously for days at a time, and may be discontinued and commenced again without opening, clearing out residual products, recharging and reclosing the retorts. there is necessarily, therefore, less labor and cost in working, and as the gas is cleaner or freer from impurities, purifying plant and material will be correspondingly less. oil gas is now employed for lighthouse service in the illumination of the lanterns on ailsa craig and as motive power in the gas engines connected with the fog horns at langness and ailsa craig lighthouse stations. it is also used largely in the lighting of railway carriages. various populous places are now introducing oil gas for house service, and he felt sure that the system is one which ought to commend itself for its future development to the careful consideration and practical skill of the members of the gas institute. * * * * * the manufacture of salt near middlesbrough.[ ] [footnote : abstract of paper read before the institution of civil engineers, may , .] by sir lowthian bell, bart., f.r.s. the geology of the middlesbrough salt region was first referred to, and it was stated that the development of the salt industry in that district was the result of accident. in , messrs. bolckow & vaughan sank a deep well at middlesbrough, in the hope of obtaining water for steam and other purposes in connection with their iron works in that town, although they had previously been informed of the probably unsuitable character of the water if found. the bore hole was put down to a depth of , feet, when a bed of salt rock was struck, which proved to have a thickness of about feet. at that time one-eighth of the total salt production of cheshire was being brought to the tyne for the chemical works on that river, hence the discovery of salt instead of water was regarded by some as the reverse of a disappointment. the mode of reaching the salt rock by an ordinary shaft, however, failed, from the influx of water being too great, and nothing more was heard of middlesbrough salt until a dozen years later, when messrs. bell brothers, of port clarence, decided to try the practicability of raising the salt by a method detailed in the paper. a site was selected , yards distant from the well of messrs. bolckow & vaughan, and the diamond rock boring company was intrusted with the work of putting down a hole in order to ascertain whether the bed of salt extended under their land. this occupied nearly two years, when the salt, feet in thickness, was reached at a depth of , feet. other reasons induced the owners of the clarence iron works to continue the bore hole for feet below the bed of salt; a depth of , feet from the surface was then reached. during the process of boring, considerable quantities of inflammable gas were met with, which, on the application of flame, took fire at the surface of the water in the bore hole. the origin of this gas, in connection with the coal measures underlying the magnesian limestone, will probably hereafter be investigated. for raising the salt, recourse was had to the method of solution, the principle being that a column of descending water should raise the brine nearly as far as the differences of specific gravity between the two liquids permitted--in the present case about feet. in other words, a column of fresh water of , feet brought the brine to within feet of the surface. for the practical application of this system a hole of say inches in diameter at the surface was commenced, and a succession of wrought iron tubes put down as the boring proceeded, the pipes being of gradually decreasing diameter, until the bottom of the salt bed was reached. the portion of this outer or retaining tube, where it passed through the bed of salt, was pierced with two sets of apertures, the upper edge of the higher set coinciding with the top of the seam, and the other set occupying the lower portion of the tube. within the tube so arranged, and secured at its lower extremity by means of a cavity sunk in the limestone, a second tube was lowered, having an outer diameter from two to four inches less than the interior diameter of the first tube. the latter served for pumping the brine. the pump used was of the ordinary bucket and clack type, but, in addition, at the surface, there was a plunger, which served to force the brine into an air vessel for the purposes of distribution. the bucket and clack were placed some feet below the point to which the brine was raised by the column of fresh water descending in the annulus formed between the two tubes. in commencing work, water was let down the annulus until the cavity formed in the salt became sufficiently large to admit of a few hours' pumping of concentrated brine. on the machinery being set in motion, the stronger brine was first drawn, which, from its greater specific gravity, occupied the lower portion of the cavity. as the brine was raised, fresh water flowed down. the solvent power of the newly admitted water was of course greater than that of water partially saturated, and being also lighter it occupied the upper portion of the excavated space. the combined effect was to give the cavity the form of an inverted cone. the mode of extraction thus possessed the disadvantage of removing the greatest quantity of the mineral where it was most wanted for supporting the roof, and had given rise to occasional accidents to the pipes underground. these were referred to in detail, and the question was started as to possible legal complications arising hereafter from new bore holes put down in close proximity to the dividing line of different properties, the pumping of brine formed under the conditions described presenting an altogether different aspect from the pumping of water or natural brine. the second part of the paper referred to the uses to which the brine was applied, the chief one being the manufacture of common salt. for this purpose the brine, as delivered from the wells, was run into a large reservoir, where any earthy matter held in suspension was allowed to settle. the clear solution was then run into pans sixty feet long by twenty feet wide by two feet deep. heat was applied at one end by the combustion of small coal, beyond which longitudinal walls, serving to support the pan and to distribute the heat, conducted the products of combustion to the further extremity, where they escaped into the chimney at a temperature of from ° to ° fahr. on the surface of the heated brine, kept at ° fahr., minute cubical crystals speedily formed. on the upper surface of these, other small cubes of salt arranged themselves in such a way that, in course of time, a hollow inverted pyramid of crystallized salt was formed. this ultimately sank to the bottom, where other small crystals united with it, so that the shape became frequently completely cubical. every second day the salt was "fished" out and laid on drainers to permit the adhering brine to run back into the pans. for the production of table salt the boiling was carried on much more rapidly, and at a higher temperature than for salt intended for soda manufacture. the crystals were very minute, and adhered together by the solidification of the brine, effected by exposure on heated flues. for fishery purposes the crystals were preferred very coarse in size. these were obtained by evaporating the brine more slowly and at a still lower temperature than when salt for soda makers was required. at the clarence works experiments had been made in utilizing surplus gas from the adjacent blast furnaces, instead of fuel, under the evaporating pans, the furnaces supplying more gas than was needed for heating air and raising steam for iron making. by means of this waste heat, from to tons of salt per week were now obtained. the paper concluded with some particulars of the soda industry. the well-known sulphuric acid process of leblanc had stood its ground for three-quarters of a century in spite of several disadvantages, and various modes of utilizing the by-products having been from time to time introduced, it had until recent years seemed too firmly established to fear any rivals. about seven years ago, however, mr. solvay, of brussels, revived in a practical form the ammonia process, patented forty years ago by messrs. hemming & dyar, but using brine instead of salt, and thus avoiding the cost of evaporation. this process consisted of forcing into the brine currents of carbonic acid and ammoniacal gases in such proportions as to generate bicarbonate of ammonia, which, reacting on the salt of the brine, gave bicarbonate of soda and chloride of ammonium. the bicarbonate was placed in a reverberatory furnace, where the heat drove off the water and one equivalent of carbonic acid, leaving the alkali as monocarbonate. near middlesbrough, the only branch of industry established in connection with its salt trade was the manufacture of soda by an ammonia process, invented by mr. schloesing, of paris. the works were carried on in connection with the clarence salt works. it was believed that the total quantity of dry soda produced by the two ammonia processes, solvay's and schloesing's, in this country was something under , tons per annum, but this make was considerably exceeded on the continent. * * * * * cotton industries of japan. the cotton plant principally cultivated in japan is of the species known as _gossypium herbaceum_, resembling that of india, china, and egypt. the plant is of short stature, seldom attaining a growth of over two feet; the flower is deciduous, with yellow petals and purple center, and the staple is short, but fine. it is very widely cultivated in japan, and is produced in thirty-seven out of the forty-four prefectures forming the empire, but the best qualities and largest quantities are grown in the southern maritime provinces of the mainland and on the islands of kiusiu and shikoku. vice consul longford, in his last report, says that the plant is not indigenous to japan, the seed having been first imported from china in the year . there are now many varieties of the original species, and the cultivation of the plant varies in its details in different localities. the variations are, however, mostly in dates, and the general grinding principles of the several operations are nearly the same throughout the whole country. the land best suited for cotton growing is one of a sandy soil, the admixture of earth and sand being in the proportion of two parts earth to one of sand. during the winter and spring months, crops of wheat or barley are raised on it, and it is when these crops have attained their full height during the month of may that the cotton is sown. about fifty days prior to the sowing a manure is prepared consisting of chopped straw, straw ashes, green grass, rice, bran, and earth from the bottom of the stagnant pools. these ingredients are all carefully mixed together in equal proportions, and the manure thus made is allowed to stand till required for use. ten days before the time fixed for sowing, narrow trenches, about one inch in depth, are dug in the furrows, between the rows of standing wheat or barleys and the manure is liberally sprinkled along them by hand. for one night before sowing the seed is steeped in water. it is then taken out, slightly mixed with straw ashes, and sown in the trenches at intervals of a few inches. when sown, it is covered with earth to the depth of half an inch, and gently trampled down by foot. four or five days after sowing, the buds begin to appear above the earth, and almost simultaneously the wheat or barley between which they grow is ripe for the sickle. while the latter is being harvested, the cotton may be left to itself, but not for very long. the buds appear in much larger numbers than the soil could support if they were allowed to grow. they have accordingly to be carefully thinned out, so that not more than five or six plants are left in each foot of length. the next process is the sprinkling of a manure composed of one part night soil and three parts water, and again, subsequent to this, there are two further manurings; one of a mixture of dried sardines, lees of oil, and lees of rice beer, which is applied about the middle of june, when the plant has attained a height of four inches; and again early in july, when the plant has grown to a height of six or seven inches, a further manuring of night soil, mixed with a larger proportion of water than before. at this stage the head of the plant is pinched off with the fingers, in order to check the excessive growth of the stem, and direct the strength into the branches, which usually number five or six. from these branches minor ones spring, but the latter are carefully pruned off as they appear. in the middle of august the flowers begin to appear gradually. they fall soon after their appearance, leaving in their place the pod or peach (_momo_), which, after ripening, opens in october by three or four valves and exposes the cotton to view. the cotton is gathered in baskets, in which it is allowed to remain till a bright, sunshiny day, when it is spread out on mats to dry and swell in the sun for two or three days. after drying, the cotton is packed in bags made of straw matting, and either sold or put aside until such time as the farmer's leisure from other agricultural operations enables him to deal with it. the average yield of cotton in good districts in japan is about lb. to the acre, but as cotton is only a secondary crop, this does not therefore represent the whole profit gained by the farmer from his land. the prefectures in which the production is largest are aichi on the east coast, osaka, hiogo, hiroshima, and yamaguchi on the inland sea, and fukui and ishikawa on the west coast. vice-consul longford says that the manufacture of cotton in japan is still in all its stages largely a domestic one. gin, spindle, and loom are all found in the house of the farmer on whose land the cotton is grown, and not only what is required for the wants of his own family is spun and woven by the female members thereof, but a surplus is also produced for sale. several spinning factories with important english machinery have been established during the last twenty years, but consul longford says that he has only known of one similar cotton-weaving factory, and that has not been a successful experiment. other so called weaving factories throughout the country consist only of a collection of the ordinary hand looms, to the number of forty or fifty, scarcely ever reaching to one hundred, in one building or shed, wherein individual manufacturers have their own special piece goods made. the first operation in the manufacture is that of ginning, which is conducted by means of a small implement called the _rokuro_, or windlass. this consists of two wooden rollers revolving in opposite directions, fixed on a frame about inches high and inches in width, standing on a small platform, the dimensions of which slightly exceed that of the frame. the operator, usually a woman, kneels on one side of the frame, holding it firm by her weight, works the roller with one hand, and with the other presses the cotton, which she takes from a heap at her side, between the rollers. the cotton passes through, falling in small lumps on the other side of the frame, while the seeds fall on that nearest the woman. the utmost weight of unginned cotton that one woman working an entire day of ten hours can give is from lb. to lb., which gives, in the end, only a little over lb. weight of ginned cotton, and her daily earnings amount to less than d. a few saw gins have been introduced into japan during the last fifteen years, but no effort has been made to secure their distribution throughout the country districts. after ginning, a certain proportion of the seed is reserved for the agricultural requirements of the following year, and the remainder is sent to oil factories, where it is pressed, and yields about one-eighth of its capacity in measurement in oil, the refuse, after pressing, being used for manure. the ginning having been finished in the country districts, the cotton is either packed in bales and sent to the dealers in the cities, or else the next process, that of carding, is at once proceeded with on the spot. this process is almost as primitive as that of the ginning. a long bamboo, sufficiently thin to be flexible, is fastened at its base to a pillar or the corner of a small room. it slopes upward into the center of the room, and from its upper end a hempen cord is suspended. to this is fastened the "bow," an instrument made of oak, about five feet in length, two inches in circumference, and shaped like a ladle. a string of coarse catgut is tightly stretched from end to end of the bow, and this is beaten with a small mallet made of willow, bound at the end with a ring of iron or brass. the raw cotton, in its coarse state, is piled on the floor just underneath the string of the bow. the string is then rapidly beaten with the mallet, and as it rises and falls it catches the rough cotton, cuts it to the required degree of fineness, removes impurities from it, and flings it to the side of the operator, where it falls on a hempen net stretched over a four-cornered wooden frame. the spaces of the net are about one-quarter of an inch square, and through these any particles of dust that may still have adhered to the cotton fall to the floor, leaving piled on top of the net the pure cotton wool in its finished state. this work is always performed by a man, and by assiduous toil throughout a long day, one man can card from ten to twenty pounds weight of raw cotton. payment is made in proportion to the work done, and in the less remote country districts is at the rate of about one penny for each pound carded. as regards spinning and weaving, in the first of these branches of cotton manufacture the japanese have largely had recourse to the aid of foreign machinery, but it is still to a much greater extent a domestic industry, or at best carried on like weaving in the establishments of cotton traders, in which a number of workers, varying from to or more, each with his own spinning wheel, are collected together. consul longford says the spinning wheel used in japan differs in no respect from that used in the country years ago or (except that bamboo forms an integral part of the materials of which it is made) from that used in england prior to the invention of the jenny. the cost of one of the wheels is about d., it will last for five or six years, and with it a woman of ordinary skill can spin about lb. of yarn in a day of ten hours, earning thereby about d. there are at present in various parts of japan, in all, spinning factories worked by foreign machinery. of four of these there is no information, but of the remainder, one has spindles; eleven, , spindles; two, , spindles; two, , spindles; and one, , spindles.--_journal soc. of arts._ * * * * * [continued from supplement, no. , page .] centrifugal extractors. by robert f. gibson. sugar machines.--besides separating the crystalline sugar and the sirup, secondary objects are to wash the crystals and to pack them in cakes. the cleansing fluid or "white liquor" is introduced at the center of the basket and is hurled against and passes through the sugar wall left from draining. the basket may be divided into compartments and the liquor guided into each. the compartments are removable boxes and are shaped to give bars or cakes or any form desired of sugar in mass. these boxes being removable cannot fit tightly against the liquor guides, and the liquor is apt to escape. this difficulty is overcome by giving the guides radial movement or by having rubber packing around the edges. sugar machines proper are of two kinds--those which are loaded, drained and then unloaded and those which are continuous in their working. the various figures preceding are of the first kind, and what has been said of vibrations applies directly to these. the general advantages claimed for continuous working over intermittent are--that saving is made of time and motive power incident to introducing charge and developing velocity, in retarding and stopping, and in discharging; that, as the power is brought into the machine continuously, no shifting of belts or ungearing is necessary; and that there are less of the dangers incident to variable motion, either in the machine itself or the belting or gearing. the magma (the mixture of crystalline sugar and sirup) is fed in gradually, by which means it is more likely to assume a position of equilibrium in the basket. there are two methods of discharging in continuous working--the sugar is thrown out periodically as the basket fills, or continuously. in neither case is the speed slackened. in the first either the upper half of the basket has an upward motion, on the lower half a downward motion (pat. , ); and through the opening thus made the sugar is thrown. fig. (r.b. palmer & sons) is a machine of this kind. the bottom, b, with the cone distributor, _a_, have downward motion. [illustration: fig. .] continuous discharge of the second kind may be brought about by having a scoop fixed to the curb (or casing), extending down into the basket and delivering the sugar over the side (pat. , ). another method will be described under "beet machines." basket.--the construction of the basket is exceedingly important. hard experience has taught this. when centrifugals were first introduced, users were compelled by law to put them below ground; for they frequently exploded, owing to the speed being suddenly augmented by inequalities in the running of the engine or to the basket being too weak to resist the centrifugal force of the overcharge. increasing the thickness merely adds to the centrifugal force, and hence to the danger, as even a perfectly balanced basket may sever. one plan for a better basket was to have more than one wall. for example, there might be an inner wall of perforated copper, then one of wire gauze, and then another of copper with larger perforations. another plan was to have an internal metallic cloth, bearing against the internally projecting ridges of the corrugations of the basket wall. a further complication is to give this internal gauze cylinder a rotation relative to the basket. the basket wall has been variously constructed. in one case it consists of wire wound round and round and fastened to uprights, commonly known as the "wire basket;" in another case of a periphery without perforations, but spirally corrugated and having an opening at the bottom for the escape of the extracted liquid; in still another of a series of narrow bars or rings, placed edgewise, packed as close as desired. an advantage of this last style is that it is easily cleaned. the best basket consists of sheet metal with bored perforations and having bands or flanges sprung on around the outside. the metal is brass, if it is apt to be corroded; if not, sheet iron. the perforations may be round, or horizontally much longer than wide vertically. one method for the manufacture of the basket wall (pat. , ) is to roll down a plate, having round perforations, to the required thickness, causing narrowing and elongation of the holes and at the same time hardening the plate by compacting its texture. long narrow slots are well adapted to catch sugar crystals, and this is not an unimportant point. round perforations are usually countersunk. instead of flanges, wire bands have been used, their lapping ends secured by solder. as to comparative wear, it maybe remarked that one perforated basket will outlast three wire ones. as to size, sugar baskets vary from inches in diameter by in. depth to by . they are made, however, in england as large as feet in diameter--a size which can be run only at a comparatively slow speed. a peculiar complication of basket deserves notice (pat. ). it had been noticed that when a charge of magma was put into a centrifugal in one mass, the sugar wall on the side of the basket was apt to form irregularly, too thick at base and of varied color. to remedy this it was suggested to have within and concentric with the basket a charger with flaring sides, into which the mixture was to be put. when this charger reached a certain rotary velocity, the magma would be hurled out over the edge by centrifugal force and evenly distributed on the wall of the main basket. spindle.--the spindle as now made is solid cast steel, and the considerations governing its size, form, material, etc., are identical with those for any spindle. in order that the basket might be replaced by another after draining, the shaft has been made telescopic, but at the expense of stability and rigidity. in fig. is shown a device to avoid crystallizations, which are apt to occur in large forgings, and would prove fatal should they creep into the upper part of the spindle proper in a hanging machine. it consists of the secondary spindle, _c_. discharging.--the drained sugar may either be lifted over the top of the basket (in machines which stop to be emptied), or be cast through openings in the bottom provided with valves. a section of the best form of valve may be seen in figs. and . fig. is a plan of the openings. the valve turns on the basket bearing. it may be constructed to open in the same direction in which the basket turns; so that when the brake is put on, the inertia of the valve operates to open it and while running to keep it closed. there are many other styles, but no other need be mentioned. [illustration: fig. .] casing.--the different styles of casing may be seen by reference to the various drawings. in one machine (not described) the casing is rigidly fixed to the basket, space enough being left between the bottom of the basket and the bottom of the casing to hold all the molasses from a charge. this arrangement merely adds to the bulk of the revolving parts, and no real advantage is gained. bearings.--the various styles of bearings can be seen by reference to the figures. one which deserves special attention is shown in fig. and fig. . in one case it consists of loose disks, in the other of loose washers, rotating on one another. they are alternately of steel and hard bronze (copper and tin). "there is probably no machine so little understood or so imperfectly constructed by the common manufacturer of sugar supplies as the high speed separator or centrifugal." unless the product of experience and good workmanship, it is a dangerous thing at high velocities. besides, its usual fate is to have an incompetent workman assigned to it, who does not use judgment in charging and running. so that designers and manufacturers have been forced not only to take into account the disturbing forces inherent in revolving bodies, but also to make allowance for poor management in running and neglect in cleaning. cane and beet machines.--the first step in the process of sugar making is the extraction of the juice from the beet or cane. this juice is obtained by pressure. the operation is not usually, but may be, performed in a special kind of centrifugal. one style (pat. , ) consists of a conical basket with a spiral flange within on the shaft, and turning on the shaft, and having a slight rotary motion relative to the basket. the material is fed in and moves downward under increased pressure, the sirup released flying out through the perforations of the basket, the whole revolving at high velocity. the solid portion falls out at the bottom. another plan suggested (pat. , ) is to let a loose cover of an ordinary cylindrical basket screw itself down into the basket, by reason of its slower velocity (owing to inertia), causing pressure on the charge. various other applications of the different styles of sugar machines are the defibration of raw sugar juice, freeing beet crystals of objectionable salts, freeing various crystals of the mother liquor, drying saltpeter. driers.--another important division of this first class of centrifugals is that of driers or, as they are variously styled, whizzers, wringers, hydro-extractors. the charge in these is never large in weight compared to a sugar charge, and its initial distribution can be made more symmetrical. the uses of driers are various, such as extracting water from clothes, cloth, silk, yarns, etc. water may be introduced at the center of the basket from above or below to wash the material before draining. a typical form of drier is shown in fig. . (pat. aug. , --w.p. uhlinger.) baskets have been made removable for use in dyeing establishments, basket and load together going into dyeing vat. yarn and similar material can be drained by a method analogous to that of hanging it upon sticks in a room and allowing the water to drip off. it is suspended from short sticks, which are held in horizontal layers around the shaft in the basket, and the action is such during the operation as to cause the yarn to stand out in radial lines. [illustration: fig. .] driers are not materially different from sugar machines. any of the devices before enumerated for meeting vibrations in the latter may be applied to the former. there is one curious invention which has been applied to driers only (pat. , --w.h. tolhurst). see fig. . a convex shaft-supporting step resting on a concave supporting base, with the center of its arc of concavity at the center of the upper universal joint, has been employed, and its movements controlled by springs, but the step was apt to be forced from its support. the drawing shows the improvement on this, which is to give the shaft-supporting step a less radius of curvature. [illustration: fig. .] an interesting form of drier has its own motor, a little steam engine, attached to the frame of the machine. see fig . this of course demands fixed bearings. the engine is very small. one size used is "× ". when a higher velocity of basket is required, we have the arrangement in fig. . [illustration: fig. .] motors.--this naturally introduces the subject of motive power. we may have the engine direct acting as above, or the power may be brought on by belting. fig. shows a drier with pulley for belting. fig. (w.h. tolhurst) shows a very common arrangement of belting and also the fast and loose pulleys. when the heaviest part of the engine is so far from the vertical shaft as to overhang the casing on one side, there is apt to be an objectionable tremor. to remedy this, it is suggested to put these heavy parts as near the shaft as possible. it has been suggested also to use the westinghouse type of engine, although the type shown in fig. works faultlessly in practice. [illustration: fig. .] one plan (pat. , ), designed to combine the advantages of a direct acting motor and an oscillating shaft, mounts the whole machine, motor and all, on a rocking frame. the spindle is of course in fixed bearings in the frame. however, the plan is not practical. [illustration: fig. .] in driers the direct acting engine has many advantages over the belt. the atmosphere is always very moist about a whizzer, and there are frequently injurious fumes. the belt will be alternately dry and wet, stretched and limp, and wears out rapidly and is liable to sever. in all machines in which the shaft oscillates, if the center of oscillation does not lie in the central plane of the belt, the tension of the latter is not uniform. this affects badly both the belt and the running. a reference to the various figures will show the best position for the pulley. the greatest difficulty experienced with belting is in getting up speed and stopping. the basket must not be started with a sudden impulse. its inertia will resist and something must give way. a gradual starting can be obtained by the slipping of the belt at first, but this is expensive. the best plan is to conduct the power through a species of friction clutch--an iron disk between two wooden ones. this has been found to work admirably. brakes.--the first centrifugals had no brakes. they ran until the friction of the bearings was sufficient to stop them. this occasioned, however, rapid wearing and too great a loss of time. the best material for a brake consists of soft wood into which shoe pegs have been driven, and which is thoroughly saturated with oil. the wooden disks referred to just above are of the same construction. the center of oscillation ought to be in the central plane of the brake as well as that of the pulley, but the preference is given to the pulley. figs. and (i) give sectional views of a brake for hanging machines. figs. , , and give two sections and a view of a brake which can be used on both hanging and standing machines. a very simple form of brake is shown in figs. , , and (a), a mere block pressing on the rim of the basket. oil and fat.--a machine in most respects like a whizzer is used for the "extraction of oil and fat and oily and fatty matters from woolen yarns and fabrics, and such other fibrous material or mixtures of materials as are from their nature affected in color or quality when hydrocarbons are used for the purpose of extracting such oily or fatty matters, and are subsequently removed from the material under treatment by the slow process of admitting steam, or using other means of raising the temperature to the respective boiling points of such hydrocarbons, and so driving them off by evaporation." in the centrifugal method carbon-bisulphide, or some other volatile agent, is admitted and is driven through the material by centrifugal force, when the necessary reactions take place, and is allowed to escape in the form of hydrocarbons. a machine differing only in slight particulars from the above is used for cleansing wool. loose fiber.--another application is the drying of loose fiber. two distinctive points deserve to be noticed in the centrifugal used for this purpose. an endless chain or belt provided with blades moves the material vertically in the basket, and discharges it over the edge. during its upward course the material is subjected to a shower of water to wash it. oil from metal chips.--very material savings are made in many factories by collecting the metal chips and turnings, coated and mixed with oil, which fall from the various machines, and extracting the oil centrifugally. the separator consists of a chip holder, having an imperforate shell flaring upward and outward from the spindle (in fixed bearings) to which it is attached. when filled, a cover is placed upon it and keyed to the spindle. between the cover and holder there is a small annular opening through which oil, but not chips, can escape. fig. (pat. , --c.f. roper) is designed (like the greater part of the drawings inserted) to show relative position of parts merely, and not relative _size_. this style of machine can be used for sugar separating (pat. , --f.p. sherman) and many other purposes, to which, however, there are other styles more especially adapted. [illustration: fig. .] filterers.--there are two distinct kinds of centrifugal filterers, working on different principles. petroleum separators (pat. , ) are of the first kind. they are in form in all respects like a sugar machine. the flakes of paraffine, stearine, etc., which are to be extracted, when chilled are very brittle and would be disintegrated upon being hurled against a plain wire gauze and would escape. even a woven fabric presents too harsh a surface. it is necessary to have a very elastic basket lining of wool, cotton, or other fibrous material. the basket itself may be either wire or perforated, but must have a perfectly smooth bottom. as the pressure of the liquor upon the filtering medium per unit of surface depends entirely upon its radial depth, mere tubes, connecting a central inlet with an annular compartment, will serve the purpose quite as well as a whole basket. in this style of machine (pat. , ) the filtering material constitutes a wall between two annular compartments. the outer one is connected with a vacuum apparatus. filterers of the second kind work on the following principle: if a cylinder be rapidly revolved in a liquid in which solid particles are suspended, the liquid will be drawn into a like rotation and the heavy particles will be thrown to the outer part of the receptacle. if a perforated cylinder is used as stirrer, the purified liquid will escape into it through the perforations and may be conducted away. the impurities, likewise, after falling down the sides of the receptacle, are carried off. the advantages of this method are that no filtering material is needed and the filtering surface is never in contact with anything but pure liquor. very fine sawdust is, to a considerable extent, employed in sugar refineries as a filtering medium. by such use the sawdust becomes mixed with sand, fine particles of cane, etc. as sawdust of such fineness is expensive, it is desirable to purify it in order to reuse it. a centrifugal (pat. , --j.v.v. booraem) built on the following principle is used for this purpose. it has been observed that by rotating rather _slowly_ small particles of various substances in water, the finer particles will be thrown outward and deposit near the circumference of the vessel, while the heavier and coarser particles will deposit nearer to or at the center, their centrifugal force not being sufficient to carry them out. a mere rod, extending radially in both directions, serves by its rotation to set the water in motion. another form of filter of this second kind (pat. , ) has a rotating imperforate basket into which the impure liquor is run. within and concentric with it is another cylinder whose walls are of some filtering medium. the liquid already partly purified by centrifugal force passes through into the inner cylinder, thus becoming further purified. centrifugal filters are used also to cleanse gums for varnishes. honey.--the simplest form of honey extractor (pat. , ) consists of a square framework, symmetrical with respect to a vertical spindle. this framework is surrounded by a wire gauze. the combs, after having the heads of the cells cut off, are placed in comb-holders against the wire netting on the four sides, the cells pointing outward. the machine is turned by hand. the honey is hurled against the walls of a receiving case and caught below. but few improvements have been made on this. the latest machines are still hand-driven, as a sufficiently high velocity can be obtained in this manner. in one style the combs are placed upon a floor which rests upon springs. the rotating box is given a slight vertical and horizontal reciprocatory motion, by which the combs are made to grate on the wire gauze sides, breaking the cells and liberating the honey. thus the labor of cutting the cells is saved. every comb has two sides, and to present each side in succession to the outside without removing from the basket, several devices have been patented. in some the comb holders are hinged in the corners of the basket, and have an angular motion of ninety degrees. decreasing the speed is sufficient to swing these. the other side is then emptied by revolving in the opposite direction. in one case each holder has a spindle of its own, connected with the main spindle by gearing and, to present opposite side, turns through °. the usual number of sides and hence of comb holders is four, but eight have been used. there are minor differences in details of construction, looking to the most convenient removal and insertion of comb, the reception of the extracted honey in cups, buckets, etc., and the best method of giving rapid rotation, which cannot be touched upon. the product of the operation is white and opaque, but upon heating regains its golden color and transparency. starch.--a centrifugal to separate starch from triturated grain, carried in suspension in water, is as follows. (pat. , --müller & decastro.) the starch water is led to the bottom of a basket, and, as starch is heavier than the gluten with which it is mixed, the former will be immediately compacted against the periphery of the basket, lodging first in the lower corner, the starch and gluten forming two distinct strata. a tube with a cutting edge enters the compacted mass so deeply as to peel off the gluten and part of the starch, which is carried through the tube to another compartment of the basket, just above, where the same operation is performed, and so on. there may be only one compartment, the tube carrying the gluten directly out of the machine. these machines are continuous working, and hence some way must be devised to carry the water off. the inner surface of the water is, as we have seen, a cylinder. when the diameter of this cylinder becomes too small, overflow must be allowed. one plan is to have an overflow opening made in the bottom of the basket in such a way that as the starch wall thickens, the opening recedes toward the center. the starch wall is either lifted out in cakes or put again in suspension by spraying water on it and conducting the mixture off. a centrifugal (pat. , ) to separate liquids from paints depends on building a wall of paint on the sides of the basket and carrying the liquids off at the center. a centrifugal (pat. , ) for assorting wood pulp, paper pulp, etc., works by massing the constituents in two or three cylindrical strata, and after action severing and removing these separately. brewing.--in brewing, centrifugals are quite useful. after the wort has been boiled with hops, albuminous matters are precipitated by the tannic acid, which must be extracted. besides these the mixture frequently contains husk, fiber, and gluten. the machine (pat. , ), although quite unique in construction, has the same principle of working as a sugar centrifugal, and need not be described. there is one point, however, which might be noticed--that air is introduced at about the same point as the material, and has an oxidizing and refrigerating effect. class i. includes also centrifugals for the following purposes: the removal of must from the grape after crushing, making butter, extracting oils from solid fats, separating the liquid and solid parts of sewerage, drying hides, skins, spent tan and the like, drying coils of wire. horizontal centrifugals.--only vertical machines have been and will be dealt with. horizontal centrifugals, that is, those whose spindles are horizontal have been made, but the great inconvenience of charging and discharging connected with them has occasioned their disuse; though in other respects for liquids they are quite as good as vertical separators. their underlying theory is practically the same as that hereinbefore discussed. class ii., creamers.--centrifugals of the second class separate liquids from liquids. there are two main applications in this class--to separate cream from milk and fusel oil from alcoholic liquors. when a liquid is to be separated from a liquid, the receptacle must be imperforate. the components of different specific gravity become arranged in distinct concentric cylindrical strata in the basket, and must be conducted away separately. in creamers the particles of cream must not be broken or subjected to any concussion, as partial churning is caused and the cream will, in consequence, sour more rapidly. the chief cause of oscillations in machines of this class, where the charge is liquid, is the waves which form on the inner surface. they may be met by allowing a slight overflow over the inner edge of the rim of the basket; or by having either horizontal partitions, or vertical, radial ones, special cases of which will be noticed. oscillations may also be met in the same manner as in sugar machines, by allowing the revolving parts to revolve about an axis through their common center of gravity. (pat. , --j. evans.) the crudest form of creamer contains a number of bottles, with their necks all directed toward the spindle, filled with milk. the necks, in which the cream collects, are graduated to tell when the operation is complete. many methods for introducing the milk into creamers have been devised. it may run in from the top at the center, or emerge from a pipe at the bottom of the basket; or the spindle may be hollow and the milk sucked up through it from a basin below. it is usual to let the milk enter under hydrostatic pressure (pat. , --d. m. weston) and let the force of expulsion of the cream be dependent on this pressure. this renders the escape quiet, and prevents churning. gravity, too, is made effective in carrying the constituents off. the cream may escape through a passage in the bottom at the center, and the skim milk at the lower outer corner; or by ingeniously managed passages both may escape at or near center. the rate of discharge can be managed by regulating the size of opening of exit passages. a curious method consists in having discharge pipes provided with valves and floats at their lower ends, dipping into the liquid (pat. , ). "the valves are opened and closed, or partially opened or closed, by the floats attached to them, these floats being so constructed and arranged with reference to their specific gravity and the specific gravity of the component parts of the liquids operated upon, that they will permit only a liquid of a determinate specific gravity to escape through the pipes to which they are respectively attached." we may have tubes directed into the different strata with cutting edges. (pat. , .) a remarkable fact noticed in their use is that these edges wear as rapidly as if solids were cut instead of liquids. the separated fluids may be received into recessed rings, having discharge pipes, the proportionate quantity discharged being regulated by the proximity of the discharge lips to the surface of the ring, and the centrifugal force being availed of to project the liquids through the discharge pipes. there is a very simple device by which a very rapid circulation of the liquid is brought about. (pat. , --c.a. backstrom.) the basket has radial vertical partitions, all but one having communicating holes, alternately in upper and lower corners. the milk is delivered into the basket on one side of this imperforate partition and must travel the whole circuit of the basket through these communicating holes, until it reaches the partition again, and then passes into a discharge pipe. thus during this long course every particle of cream escapes to the center. as the holes are close to the walls of the basket, the cream has not the undulatory motion of the milk, which would injure it. the greater the number of partitions, the longer is the travel of the milk, and the more rapid the circulation. blades have been devised similar to the above, having communicating passages extending the whole width of the blade, but we see that here the cream would circulate with the milk; which must not be allowed. curved blades have been used, and paddles and stirrers, to set the milk in motion, but to them the same objection may be made. [illustration: fig. ] fig. (pat. , --c.a. backstrom) illustrates one of the latest and best styles of creamers. the milk enters at c. the skim milk passes into tube, t, and the cream goes to the center and passes out of the openings in the bottom, _k^{l}_, _k^{ }_, and _k^{ }_, out of the slit, k, and thence out through d^{ }. the skim milk moves through t, becoming more thoroughly separated all the while, and at each of the radial branch tubes, t^{ }, t^{ }, t^{ }, and t^{ }, some cream leaves it and goes to the center, while it passes down out of slit, t^{ }, and thence out of d^{ }. fig. (pat. , --c.a. backstrom) shows another very late style of creamer. a pipe delivers the milk into p^{ }. passing out of the tube separation takes place, and cream falls down the center to p^{ } and out of o^{ }. when the compartment under the first shelf becomes full of the skim milk, the latter passes up through the slot, s, strikes a radial partition, r, and its course is reversed. here more cream separates and passes to center and falls directly, and so on through the whole series of annular compartments, until the top one, when the skim milk enters tube t^{ } and passes out of o^{ }. by this operation there are substantially repeated subjections of specified quantities of milk to the action of centrifugal force, bringing about a thorough separation. by changing the course of the milk in direction, its path is made longer. this machine can run at much lower speed than many other styles, and yet do the same work. [illustration: fig. ] class iii., solids from solids.--as for grain machines, which are in this class, it may be said that in centrifugal flour bolters, bran cleaners, and middlings purifiers, though theoretically centrifugal force plays an important part in their action, yet practically the real separation is brought about by other agencies: in some by brushes which rub the finer particles through wire netting as they rotate against it. the principle exhibited in a separator of grains and seeds is very neat. (pat. , .) see fig. . that part of the machine with which we have to do consists essentially of a horizontal revolving disk. the mixed grains are cast on this disk, pass to the edge, and are hurled off at a tangent. suppose at a. each particle is immediately acted on by three forces. for all particles of the same size and having the same velocity the resistance of the air may be taken the same, that is, proportional to the area presented. the acceleration of gravity is the same; but the inertia of the heavier grain is greater. the resultant of the two conspiring forces r and (m_v_^{ })/ varies, and is greater for a heavier grain. therefore, the paths described in the air will vary, especially in length; and how this is utilized the drawing illustrates. [illustration: fig. .] ore.--in ore machines there is one for pulverizing and separating coal (pat. , ), in which there is a breaker provided with helical blades or paddles, partaking of rapid rotary motion within a stationary cylinder of wire netting. the dust, constituting the valuable part of the product, is hurled out as fast as formed. in this style of machine, beaters are necessary not only for pulverizing, but to get up rotary motion for generating centrifugal force. in the classes preceding, the friction of the basket sufficed for this latter purpose; but here there is no rotating basket and no definite charge. as the material falls through the machine, separation takes place. various kinds of ore may be treated in the same manner. an "ore concentrator" (pat. , ), as it is called, consists of a pan having rotary and oscillatory motions. crushed ore is delivered over the edge in water. the heavy particles of the metal are thrown by centrifugal force against the rim of the pan, overcoming the force of the water, which carries the sand and other impurities in toward the center and away. amalgamators.--the best ore centrifugal or separator is what is called an "amalgamator." the last invention (pat. , , white) consists essentially of a pan, a meridian section of which would give a curve whose normal at any point is in the direction of the resultant of the centrifugal force at that point and gravity. there is a cover to this pan whose convexity almost fits the concavity of the pan, leaving a space of about an inch between. crushed ore with water is admitted at the center between the cover and the pan, and is driven by centrifugal force through a mass of mercury (which occupies part of this space between the two) and out over the edge of the pan. the particles of metal coming in contact with the mercury amalgamate, and as the speed is regulated so that it is never great enough to hurl the mercury out, nothing but sand, water, etc., escape. there have been many different constructions devised, but this general principle runs through all. by having annular flanges running down from the cover with openings placed alternately, the mixture is compelled to follow a tortuous course, thus giving time for all the gold or other metal to become amalgamated. there are ridges in the pan, too, against which the amalgam lodges. it is claimed for this machine that not a particle of the precious metal is lost, and experiments seem to uphold the claim. a machine for separating fine from coarse clay for porcelain or for separating the finer quality of plumbago from the coarser for lead pencils uses an imperforate basket, against the wall of which the coarser part banks and catches under the rim. the finer part forms an inner cylindrical stratum, but is allowed to spill over the edge of the rim. the mixture is introduced at the bottom of the basket at the center. class iv., gases and solids.--there is a very simple contrivance illustrating machines of this class used to free air from dust or other heavy solid impurities which may be in suspension. see fig. . the air enters the passage, b (if it has no considerable velocity of itself, it must be forced in), forms a whirlpool in the conically shaped receptable, a, and passes up out of the passage, d. the heavy particles are thrown on the sides and collect there and fall through opening, c, into some closed receiver. [illustration: fig. ] class v., gases and liquids.--the occluded gases in steel and other metal castings, if not separated, render the castings more or less porous. this separation is effected by subjecting the molten metal to the action of centrifugal force under exclusion of air, producing not only the most minute division of the particles, but also a vacuum, both favorable conditions for obtaining a dense metal casting. most of the devices for drying steam come under this head. such are those in which the steam with the water in suspension is forced to take a circular path, by which the water is hurled by centrifugal force against the concave side of the passage and passes back to the water in the boiler. speed.--the centrifugal force of a revolving particle varies, as we have seen, as the square of the angular velocity, so that the effort has been to obtain as high a number of revolutions per minute as was consistent with safety and with the principle of the machine. for example, creamers which are small and light make , revolutions per minute, though the latest styles run much more slowly. driers and sugar machines vary from to , , while on the other hand the necessity of keeping the mercury from hurling off in an amalgamator prevents its turning more rapidly than sixty or eighty times a minute. however, speed in another sense, the speed with which the operation is performed, is what especially characterizes centrifugal extractors. in this particular a contrast between the old methods and the new is impressive. under the action of gravity, cream rises to the milk's surface, but compare the hours necessary for this to the almost instantaneous separation in a centrifugal creamer. the sugar manufacturer trusted to gravity to drain the sirup from his crystals, but the operation was long and at best imperfect. an average sugar centrifugal will separate pounds of magma perfectly in three minutes. gold quartz which formerly could not pay for its mining is now making its owners' fortunes. it is boasted by a southern company that whereas they were by old methods making twenty-five _cents_ per ton of gold quartz, they now by the use of the latest amalgamator make twenty-five _dollars_. centrifugal force, as applied in extractors, has opened up new industries and enlarged old ones, has lowered prices and added to our comforts, and centrifugal extractors may well command, as they do, the admiration of all as wonderful examples of the way in which this busy age economizes time. * * * * * a new type of railway car. [illustration: fig. .--car with lateral passageways.] figs. and give a perspective view and plan of a new style of car recently adopted by the bone-guelma railroad company, and which has isolated compartments opening upon a lateral passageway. in this arrangement, which is due to mr. desgranges, the lateral passageway does not extend all along one side of the car, but passes through the center of the latter and then runs along the opposite side so as to form a letter s. the car consists in reality of two boxes connected beneath the transverse passageway, but having a continuous roof and flooring. the two ends are provided with platforms that are reached by means of steps, and that permit one to enter the corresponding half of the car or to pass on to the next. the length from end to end is feet in the mixed cars, comprising two first-class and four second-class compartments, and feet in cars of the third class, with six compartments. the width of the compartments is . and feet, according to the class. the passageway is inches in width in the mixed cars, and in those of the third class. the roof is so arranged as to afford a circulation of cool air in the interior. [illustration: fig. .--plan.] the application of the zigzag passageway has the inconvenience of slightly elongating the car, but it is advantageous to the passengers, who can thus enjoy a view of the landscape on both sides of the train.--_la nature._ * * * * * foundations of the central viaduct of cleveland, o. the central viaduct, now under construction in the city of cleveland, is probably the longest structure of the kind devoted entirely to street traffic. the superstructure is in two distinct portions, separated by a point of high ground. the main portion, extending across the river valley from hill street to jennings avenue, is , feet long on the floor line, including the river bridge, a swing feet in length; the other portion, crossing walworth run from davidson street to abbey street, is , feet long. add to these the earthwork and masonry approaches, , feet long, and we have a total length of , feet. the width of roadway is feet, sidewalks feet each. the elevation of the roadway above the water level at the river crossing is feet. the superstructure is of wrought iron, mainly trapezoidal trusses, varying in length from feet to feet. the river piers are of first-class masonry, on pile and timber foundations. the other supports of the viaduct are wrought iron trestles on masonry piers, resting on broad concrete foundations. the pressure on the material beneath the concrete, which is plastic blue clay of varying degrees of stiffness mixed with fine sand, is about one ton per square foot. the cuyahoga valley, which the viaduct crosses from bluff to bluff, is composed mainly of blue clay to a depth of over feet below the river level. no attempt is made to carry the foundation to the rock. white oak piles from to feet in length and inches in diameter at small end are driven for the bridge piers either side of the river bed, and these are cut off with a circular saw feet below the surface of the water. excavation by dredging was made to a depth of feet below where the piles are cut off to allow for the rising of the clay during the driving of the piles. the piles are spaced about feet inches each way, center to center. the grillage or platform covering the piles consists of courses of white oak timber, inches by inches, having a few pine timbers interspersed so as to allow the mass to float during construction. the lower half of the platform was built on shore, care being taken to keep the lower surface of the mass of timber out of wind. the upper and lower surfaces of each timber were dressed in a daniels planer, and all pieces in the same course were brought to a uniform thickness. the timbers in adjacent courses are at right angles to each other. the lower course is about feet by feet, the top course about by feet, thus allowing four steps of one foot each all around. the first course of masonry is feet by feet inches; the first course of battered work is feet ½ inches by feet inches. thus the area of the platform on the piles is , square feet, and of the first batter course of masonry . square feet, or in the ratio of . to . the height of the masonry is feet above the timber, or ½ feet above the water. the number of piles in each foundation is . the average load per pile is about tons, and the estimated pressure per square inch of the timber on the heads of the piles is about pounds. to prevent the submersion of the lower courses of masonry during construction, temporary sides of timber were drift-bolted to the margin of the upper course of the timber platform, and carried high enough to be above the surface of the water when the platform was sunk to the head of the piles by the increasing weight of masonry. the center pier is octagonal, and is built in the same general manner as to foundations as the shore piers, but the piles are cut off feet below water, and there are eighteen courses of timber in the grillage. the diameter of the platform between parallel sides is feet, while that of the lower course of battered masonry is but feet. the areas are as , to , , or as to nearly. the pressure per square inch of timber on the heads of the piles is about the same as stated above for the shore piers. the number of piles under the center pier is . the risks and delays by this method of constructing the foundations were much less, and the cost also, than if an ordinary coffer dam had been used. also the total weight of the piers is much less, as that portion below a point about two feet below the water adds nothing to their weight. the piles were driven with a cram steam hammer weighing two tons, in a frame weighing also two tons. the iron frame rests directly upon the head of the pile and goes down with it. the fall of the hammer is about inches before striking the pile. the total penetration of the piles into the clay averaged feet. the settlement of the pile during the final strokes of the hammer varied from one quarter to three quarters of an inch per blow. there are masonry pedestals, of which eight are large and heavy, carrying spans of considerable length. they will all be built upon concrete beds, except a few near the river on the north side, where piles are required. the four abutments with their retaining walls are of first-class rock-faced masonry. the footing courses are stepped out liberally, so as to present an unusually large bottom surface. they rest on beds of concrete feet thick. the foundation pits are about feet below the top of the bluffs, and are in a material common to the cleveland plateau, a mixture of blue sand and clay, with some water. the estimated load of masonry on the earth at the bottom of the concrete is one and seven tenths tons to the square foot. two of the large abutments were completed last season. they show an average settlement of three eighths of an inch since the lower footing courses were laid. the facts and figures here given regarding the viaduct were kindly furnished by the city civil engineer, c.g. force, who has the work in charge.--_jour. asso. of eng. societies._ * * * * * for sticking paper to zinc, use starch paste with which a little venice turpentine has been incorporated, or else use a dilute solution of white gelatine or isinglass. * * * * * centrifugal pumps at mare island navy yard, california.[ ] [footnote : built by the southwark foundry and machine company, of philadelphia.] by h.r. cornelius. in december, , bids were asked for by the united states government on pumping machinery, to remove the water from a dry dock for vessels of large size. the dimensions of the dock, which is situated on san pablo bay, directly opposite the city of vallejo, are as follows: five hundred and twenty-nine feet wide at its widest part, feet deep, with a capacity at mean tide of , , gallons. after receiving the contract, several different sizes of pumps were considered, but the following dimensions were finally chosen: two inch centrifugal pumps, with runner inches in diameter and discharge pipes inches, each driven direct by a vertical engine with inch diameter cylinder and inch stroke. these were completed and shipped in june, , on nine cars, constituting a special train, which arrived safely at its destination in the short space of two weeks, and the pumps were there erected on foundations prepared by the government. from the "report of the chief of bureau of yards and docks" i quote the following account of the official tests: "the board appointed to make the test resolved to fill the dock to about the level that would attain in actual service with a naval ship of second rate in the dock, and the tide at a stage which would give the minimum pumping necessary to free the dock. the level of the th altar was considered as the proper point, and the water was admitted through two of the gates of the caisson until this level was reached; they were then closed. the contents of the dock at this point is , , gallons. "the trial was commenced and continued to completion without any interruption in a very satisfactory manner. "in the separate trials had of each pump, the average discharge per minute was taken of the whole process, and there was a singular uniformity throughout with equal piston speed of the engine. "it was to be expected, and in a measure realized, that during the first moments of the operations, when the level of the water in the dock was above the center of the runner of the pumps, that the discharge would be proportioned to the work done, where no effort was necessary to maintain a free and full flow through the suction pipes; but as the level passed lower and farther away from the center there was no apparent diminution of the flow, and no noticeable addition to the load imposed on the engine. the variation in piston speed, noted during the trial, was probably due to the variation of the boiler pressure, as it was difficult to preserve an equal pressure, as it rose in spite of great care, owing to the powerful draught and easy steaming qualities of the boilers. "after the trial of the second pump had been completed the dock was again filled through the caisson, and as both pumps were to be tried, the water was admitted to a level with the d altar, containing , , gallons, which was seven feet above the center of the pumps; this was in favor of the pumps for the reasons before stated. in this case all the boilers were used. "everything moved most admirably, and the performance of these immense machines was almost startling. by watching the water in the dock it could be seen to lower bodily, and so rapidly that it could be detected by the eye without reference to any fixed point. "the well which communicates with the suction tunnel was open, and the water would rise and fall, full of rapid swirls and eddies, though far above the entrance of these tunnels. through the man hole in the discharge culvert the issuance from the pipes could be seen, and its volume was beyond conception. it flowed rapidly through the culvert, and its outfall was a solid prism of water, the full size of the tunnel, projecting far into the river. "during a pumping period of minutes, the dock had been emptied from the twenty-third to two inches above the sixth altar, containing , , gallons, an average throughout of , gallons per minute. at one time, when the revolutions were increased to per minute, the discharge was , gallons per minute. this is almost a river, and is hardly conceivable. after the pumps were stopped, on this occasion, tests were made with each in succession as to the power of the ejectors with which each is fitted to recharge the pumps. "the valves in the discharge pipe were closed and steam admitted to the ejector, the pump being still and no water in the gauge glass on the pump casing, which must be full before the pumps will work. the suction pipe of the ejector is only two and a half inches in diameter, the steam pipe one inch in diameter. to fully charge the pumps at this point required filling the pump casing and the suction pipe containing about , gallons; this was accomplished in four minutes, and when the gauge glass was full the pump operated instantly and with certainty, discharging its full volume of water. "i went on several occasions down in the valve pits on the ladder of the casing, and to all accessible parts while in motion at its highest speed, and there was no undue vibration, only a uniform murmur of well-balanced parts, and the peculiar clash of water against the sides of the casing as its velocity was checked by the blank spaces in the runner. "the pumps are noisy while at work, due to the clashing of the water just mentioned, but it affords a means of detecting any faulty arrangements of the runner or unequal discharge from any of its openings. while moving at a uniform speed, this clashing has a tone whose pitch corresponds with that velocity of discharge, and if this tone is lacking in quality, or at all confused, there is want of equality of discharge through the various openings of the runner. to this part i gave close attention, and there was nothing that the ear could detect to indicate aught but the nicest adjustment. the bearings of the runners worked with great smoothness, and did not become at all heated. through a simple, novel arrangement, these bearings are lubricated and kept cool. there is a constant circulation of water from the pumps by means of a small pipe, which completes a circuit to an annular in the bearings back to the discharge pipe while the pump is in motion, requiring no oil and making it seemingly impossible to heat these bearings. "the large cast steel valves placed in the embouchement of the casing, it was thought, might act to check the free discharge, and arrangements were provided for raising and keeping them open by a long lever key attached to their axes of revolution, but, to our great surprise, at the first gush from the pumps these valves, weighing nearly , pounds, were lifted into their recessed chambers, giving an unobstructed opening to the flow, and they floated on its surface unsupported, save by the swiftly flowing water, without a movement, while the pump was in operation. "the steam-actuated valves in the suction and discharge pipes worked very well, and the water cushion gave a slow, uniform motion, and without shock, either in opening or closing them. "the engines worked noiselessly, without shock or labor. at no time during the trial was the throttle valve open more than three-eighths of an inch. "the indicator cards taken at various intervals gave horse power, and the revolutions did not exceed at any time, though it was estimated that horse power and revolutions would be necessary to attain the requisite delivery. so that there is a large reserve of power available at any time. "the erection of this massive machinery has been admirably done. the parts, as sent from the shops of the contractor, have matched in all cases without interference here; and, when lowered into place, its final adjustment was then made without the use of chisel or file, and has never been touched since. "the joints of the steam and water connections were perfect, and the method of concentrating all valves, waste pipes, and important movements at the post of the engineer in charge gives him complete control of the whole system of each engine and pump without leaving his place, and reduces to a minimum the necessary attendance. all the parts are strong and of excellent design and workmanship; simple, and without ornamentation. "looking down upon them from a level of the pump house gallery, they are impressive and massive in their simplicity. "the government is well worth of congratulation in possessing the largest pumping machinery of this type and of the greatest capacity in the world, and the contractors have reason to be proud of their work."--_proc. eng. club._ * * * * * the part that electricity plays in crystallization. since the discovery of the multiplying galvanometer, we know for an absolute certainty that in every chemical action there is a production of electricity in a more or less notable quantity, according to the nature of the bodies in presence. though, in the play of _affinity_, there is a manifestation of electricity, is it the same with _cohesion_, which also is a chemical force? we know, on another hand, that, on causing electricity to intervene, we bring about the crystallization of a large number of substances. but is the converse true? is spontaneous crystallization accompanied with an appreciable manifestation of electricity? if we consult the annals of science and works treating on electricity in regard to this subject, we find very few examples and experiments proper to elucidate the question. mr. mascart is content to say: "some experiments seem to indicate that the solidification of a body produces electricity." mr. becquerel does more than doubt--he denies: "as regards the disengagement of electricity in the changing of the state of bodies, we find none." this assertion is too sweeping, for further along we shall cite facts that prove, on the contrary, that in the phenomena of crystallization (to speak of this change of state only) there is an unequivocal production of electricity. let us remark, in the first place, that when a number of phenomena of physical and chemical order incontestably testify to the very intimate correlation that exists between the molecular motions of bodies and their electrical state, it would not be very logical to grant that electricity is absent in crystallization. thus, to select an example from among physical effects, the vibratory phenomena that occur in telephone transmissions, under the influence of a very feeble electric current, show us that the molecular constitution of a solid body is extremely variable, although within slight limits. the feeblest modification in the electric current may be shown by molecular motions capable of propagating themselves to considerable distances in the conducting wire. conversely, it is logical to suppose that a modification in the molecular state of a body must bring electricity into play. if, in the phenomena of solidification, and particularly of crystallization, we collect but small quantities of electricity, that may be due to the fact that, under the experimental conditions involved, the electricity is more or less completely absorbed by the work of crystal building. on another hand, the behavior of electricity shows in advance the multiple role that this agent may play in the various physical, chemical, and mechanical phenomena. there is no doubt that electricity exists immovable or in circulation everywhere, latent or imperceptible, around us, and within ourselves, and that it enters as a cause into the majority of the chemical, physical, and mechanical phenomena that are constantly taking place before our eyes. a body cannot change state, nature, temperature, form, or place, even, without electricity being brought into play, and without its accompanying such modifications, if it presides therein. like heat, it is _the_ natural agent _par excellence_; it is the invisible and ever present force which, in the ultimate particles of matter, causes those motions, vibrations, and rotations that have the effect of changing the properties of bodies. upon entering their intimate structure, it orients or groups their atoms, and separates their molecules or brings them together. from this, would it not be surprising if it did not intervene in the wonderful phenomenon of crystallization? crystallization, in fact, depends upon _cohesion_, and, in the thermic theory, this force is not distinct from affinity, just as solution and dissociation are not distinct from combination. on this occasion, it is necessary to say that, between affinity, heat, and electricity there is such a correlation, such a dependency, that physicists have endeavored to reduce to one single principle all the causes that are now distinct. the mechanical theory of heat has made a great stride in this direction. the equivalence of the thermic, mechanical and chemical forces has been demonstrated; the only question hereafter will be to select from among such forces the one that must be adopted as the sole principle, in order to account for all the phenomena that depend upon these causes of various orders. but in the present state of science, it is not yet possible to explain completely by heat or electricity, taken isolatedly, all the effects dependent upon the causes just mentioned. we must confine ourselves for the present to a study of the relations that exist between the principal natural forces--affinity, molecular forces, heat, electricity, and light. but from the mutual dependence of such forces, it is admitted that, in every natural phenomenon, there is a more or less apparent simultaneous concurrence of these causes. in order to explain electric or magnetic phenomena, and also those of crystallization, it is admitted that the atoms of which bodies are composed are surrounded, each of them, with a sort of atmosphere formed of electric currents, owing to which these atoms are attracted or repelled on certain sides, and produce those varied effects that we observe under different circumstances. according to this theory, then, atoms would be small electro-magnets behaving like genuine magnets. entirely free in gases, but less so in liquids and still less so in solids, they are nevertheless capable of arranging themselves and of becoming polarized in a regular order, special to each kind of atom, in order to produce crystals of geometrical form characteristic of each species. thus, as mr. saigey remarks in "physique moderne" (p. ): "so long as the atmospheres of the molecules do not touch each other, no trace of cohesion manifests itself; but as soon as they come together force is born. we understand why the temperatures of fusion and solidification are fixed for the same body. such effects occur at the precise moment at which these atmospheres, which are variable with the temperature, have reached the desired diameter." [illustration: figs. ., ., and .] although the phenomenon of crystallization does not essentially depend upon temperature, but rather upon the relative quantity of liquid that holds the substance in solution, it will be conceived that a moment will arrive when, the liquid having evaporated, the atmospheres will be close enough to each other to attract each other and become polarized and symmetrically juxtaposed, and, in a word, to crystallize. before giving examples of the production of electricity in the phenomenon of crystallization, it will be well to examine, beforehand, the different circumstances under which electricity acts as the determining cause of crystallization or intervenes among the causes that bring about the phenomenon. in the first place, two words concerning crystallization itself: we know that crystallization is the passage, or rather the result of the passage, of a body from a liquid or gaseous state to a solid one. it occurs when the substance has lost its cohesion through any cause whatever, and when, such cause ceasing to act, the body slowly returns to a solid state. under such circumstances, it may take on regular, geometrical forms called crystalline. such conditions are brought about by different processes--fusion, volatilization, solution, the dry way, wet way, and electric way. further along, we shall give some examples of the last named means. let us add that crystallization may be regarded as a general property of bodies, for the majority of substances are capable of crystallizing. although certain bodies seem to be amorphous at first sight, it is only necessary to examine their fracture with a lens or microscope to see that they are formed of a large number of small juxtaposed crystals. many amorphous precipitates become crystalline in the long run. in the examination of the various crystallizations that occupy us, we shall distinguish the following: ( ) those that are produced through the direct intervention of the electric current; ( ) those in which electricity is manifestly produced by small voltaic couples resulting from the presence of two different metals in the solution experimented with; ( ) those in which there are no voltaic couples, but in which it is proved that electricity is one of the causes that concur in the production of the phenomenon; ( ) finally, those in which it is rational, through analogy with the preceding, to infer that electricity is not absent from the phenomenon. i. we know that, by means of voltaic electricity or induction, we can crystallize a large number of substances. despretz tried this means for months at a time upon carbon, either by using the electricity from a ruhmkorff coil or the current from a weak daniell's battery. in both cases, he obtained on the platinum wires a black powder, in which were found very small octohedral crystals, having the property of polishing rubies rapidly and perfectly--a property characteristic of diamonds. the use of voltaic apparatus of high tension has allowed mr. cross to form a large number of mineral substances artificially, and among these we may mention carbonate of lime, arragonite, quartz, arseniate of copper, crystalline sulphur, etc. as regards products formed with the concurrence of electricity (oxides, sulphides, chlorides, iodides, etc.), see "des forces physico-chimiques," by becquerel (p. ). there is no doubt as to the part played by electricity in the chemical effects of electro-metallurgy, but it will not prove useless for our subject to remark that when, in this operation, the current has become too weak, the deposit of metal, instead of forming in a thin, adherent, and uniform layer, sometimes occurs under the form of protuberances and crystalline, brittle nodules. when, on the contrary, the current is very strong, the deposit is pulverulent, that is, in a confused crystallization or in an amorphous state. further along, we shall find an application of this remark. we obtain, moreover, all the intermediate effects of cohesion, form, and color of galvanic deposits. when, into a solution of acetate of lead, we pass a current through two platinum electrodes, we observe the formation, at the negative pole, of numerous arborizations of metallic lead that grow under the observer's eye (fig. ). the phenomenon is of a most interesting character when, by means of solar or electric light, we project these brilliant vegetations on a screen. one might believe that he was witness of the rapid growth of a plant (fig. ). the same phenomenon occurs none the less brilliantly with a solution of nitrate of silver. a large number of saline solutions are adapted to these decompositions, in which the metal is laid bare under a crystalline form. further along we shall see another means of producing analogous ramifications, without the direct use of the electric current.--_c. decharme, in la lumiere electrique._ * * * * * electric time. by m. lippmann. the unit of time universally adopted, the second, undergoes only very slow secular variations, and can be determined with a precision and an ease which compel its employment. still it is true that the second is an arbitrary and a variable unit--arbitrary, in as far as it has no relation with the properties of matter, with physical constants; variable, since the duration of the diurnal movement undergoes causes of secular perturbation, some of which, such as the friction of the tides, are not as yet calculable. we may ask if it is possible to define an absolutely invariable unit of time; it would be desirable to determine with sufficient precision, if only once in a century, the relation of the second to such a unit, so that we might verify the variations of the second indirectly and independently of any astronomical hypothesis. now, the study of certain electrical phenomena furnishes a unit of time which is absolutely invariable, as this magnitude is a specific constant. let us consider a conductive substance which may always be found identical with itself, and to fix our ideas let us choose mercury, taken at the temperature of ° c., which completely fulfills this condition. we may determine by several methods the specific electric resistance, [rho], of mercury in absolute electrostatic units; [rho] is a specific property of mercury, and is consequently a magnitude absolutely invariable. moreover, [rho] is _an interval of time_. we might, therefore, take [rho] as a unit of time, unless we prefer to consider this value as an imperishable standard of time. in fact, [rho] is not simply a quantity the measure of which is found to be in relation with the measure of time. it is a concrete interval of time, disregarding every convention established with reference to measures and every selection of unit. it may at first sight, appear singular that an interval of time is found in a manner hidden under the designation _electric resistance_. but we need merely call to mind that in the electrostatic system the intensities of the current are speeds of efflux and that the resistances are times, i.e., the times necessary for the efflux of the electricity under given conditions. we must, in particular, remember what is meant by the specific resistance, [rho] of mercury in the electrostatic system. if we consider a circuit having a resistance equal to that of a cube of mercury, the side of which = the unit of length, the circuit being submitted to an electromotive force equal to unity, this circuit will take a given time to be traversed by the unit quantity of electricity, and this time is precisely [rho]. it must be remarked that the selection of the unit of length, like that of the unit of mass, is indifferent, for the different units brought here into play depend on it in such a manner that [rho] is not affected. it is now required to bring this definition experimentally into action, i.e., to realize an interval of time which may be a known multiple of [rho]. this problem may be solved in various ways,[ ] and especially by means of the following apparatus. [footnote : in this system the measurement of time is not effected, as ordinarily, by observing the movements of a material system, but by experiments of equilibrium. all the parts of the apparatus remain immovable, the electricity alone being in motion. such appliances are in a manner clepsydræ. this analogy with the clepsydræ will be perceived if we consider the form of the following experiment: two immovable metallic plates constitute the armatures of a charged condenser, and attract each other with a force, f. if the plates are insulated, these charges remain constant, as well as the force, f. if, on the contrary, we connect the armatures of resistance, r, their charges diminish and the force, f, becomes a function of the time, _t_; the time, _t_, inversely becomes a function of p. we find _t_ by the following formula: t = [rho] × (ls / s[pi]es) × log hyp(f /f) f and f being the values of the force at the beginning and at the end of the time, _t_. the above formula is independent of the choice of units. if we wish _t_ to be expressed in seconds, we must give [rho] the corresponding value ([rho] = . x ^- ). if we take [rho] as a unit we make [rho] = , and we find the absolute value of the time by the expression: (ls) / ( [pi]es) log hyp(f /f) we remark that this expression of time contains only abstract numbers, being independent of the choice of the units of length and force. s and _e_ denote surface and the thickness of the condenser; _s_ and _l_ the section and the length of a column of mercury of the resistance, r. this form of apparatus enables us practically to measure the notable values of _t_ only if the value of the resistance, r, is enormous, the arrangement described in the text has not the same inconvenience.] a battery of an arbitrary electromotive force, e, actuates at the same time the two antagonistic circuits of a differential galvanometer. in the first circuit, which has a resistance, r, the battery sends a continuous current of the intensity, i; in the second circuit the battery sends a discontinuous series of discharges, obtained by charging periodically by means of the battery a condenser of the capacity, c, which is then discharged through this second circuit. the needle of the galvanometer remains in equilibrium if the two currents yield equal quantities of electricity during one and the same time, [tau]. let us suppose this condition of equilibrium realized and the needle remaining motionless at zero; it is easy to write the conditions of equilibrium. during the time, [tau], the continuous current yields a e quantity of electricity = -- [tau]; on the other hand, each charge of r the condenser = ce, and during the time, [tau], the number of [tau] discharges = -----, t being the fixed time between two discharges; t [tau] and t are here supposed to be expressed by the aid of an arbitrary unit of time; the second circuit yields, therefore, a [tau] quantity of electricity equal to ce × -----. the condition of t e [tau] equilibrium is then ---[tau] = ce × ----- ; or, more simply, t = cr. r t c and r are known in absolute values, i.e., we know that c is equal to _p_ times the capacity of a sphere of the radius, _l_; we have, therefore, c = _pl_; in the same manner we know that r is equal to _q_ times the resistance of a cube of mercury having l for its side. we l [rho] have, therefore, r = q[rho] --- = q ----- ; and consequently t = pq[rho]. l² l such is the value of _t_ obtained on leaving all the units undetermined. if we express [rho] as a function of the second, we have _t_ in seconds. if we take [rho] = , we have the absolute value [theta] of the same interval of time as a function of this unit; we have simply [theta] = _pq_. if we suppose that the commutator which produces the successive charges and discharges of the condenser consists of a vibrating tuning fork, we see that the duration of a vibration is equal to the product of the two abstract numbers, _pq_. it remains for us to ascertain to what degree of approximation we can determine _p_ and _q_. to find _q_ we must first construct a column of mercury of known dimensions; this problem was solved by the international bureau of weights and measures for the construction of the legal ohm. the legal ohm is supposed to have a resistance equal to . times that of a cube of mercury of . meter, side measurement. the approximation obtained is comprised between / and / . to obtain _p_, we must be able to construct a plane condenser of known capacity. the difficulty here consists in knowing with a sufficient approximation the thickness of the stratum of air. we may employ as armatures two surfaces of glass, ground optically, silvered to render them conductive, but so slightly as to obtain by transparence fizeau's interference rings. fizeau's method will then permit us to arrive at a close approximation. in fine, then, we may, _a priori_, hope to reach an approximation of one hundred-thousandth of the value of _pq_. independently of the use which may be made of it for measuring time in absolute value, the apparatus described possesses peculiar properties. it constitutes a kind of clock which indicates, registers, and, if needful, corrects automatically its own variations of speed. the apparatus being regulated so that the magnetic needle may be at zero, if the speed of the commutator is slightly increased, the equilibrium is disturbed and the magnetic needle deviates in the corresponding direction; if on the contrary the speed diminishes, the action of the antagonistic circuit predominates, and the needle deviates in the contrary direction. these deviations, when small, are proportional to the variations of speed. they may be, in the first place, observed. they may, further, be registered, either photographically or by employing a redier apparatus, like that which m. mascart has adapted to his quadrant electrometer; finally, we may arrange the redier to react upon the speed so as to reduce its variations to zero. if these variations are not completely annulled, they will still be registered and can be taken into account. as an indicator of variations this apparatus can be of remarkable sensitiveness, which may be increased indefinitely by enlarging its dimensions. with a battery of volts, a condenser of a microfarad, discharges per second, and a thomson's differential galvanometer sensitive to ^{- } amperes, we obtain already a sensitiveness of / , i.e., a variation of / in the speed is shown after some seconds of a deviation of one millimeter. even the stroboscopic method does not admit of such sensitiveness. we may therefore find, with a very close approximation, a speed always the same on condition that the solid parts of the apparatus (the condenser and the resistance) are protected from causes of variation and used always at the same temperature. doubtless, a well-constructed astronomical clock maintains a very uniform movement; but the electric clock is placed in better conditions for invariability, for all the parts are massive and immovable; they are merely required to remain unchanged, and there is no question of the wear and tear of wheel-work, the oxidation of oils, or the variations of weight. in other words, the system formed by a condenser and a resistance constitutes a standard of time easy of preservation. * * * * * new method of maintaining the vibration of a pendulum. a recent number of the _comptes rendus_ contains a note by m.j. carpentier describing a method of maintaining the vibrations of a pendulum by means of electricity, which differs from previous devices of the same character in that the impulse given to the pendulum at each vibration is independent of the strength of the current employed, and that the pendulum itself is entirely free, save at the point of suspension. the vibrations are maintained, not by direct impulsion, but by a slight horizontal displacement of the point of suspension in alternate directions. this, as m. carpentier observes, is the method which we naturally adopt in order to maintain the amplitude of swing of a heavy body suspended from a cord held in the hand. the required movement of the point of suspension is effected by means of a polarized relay, through the coils of which the current is periodically reversed by the action of the pendulum, in a manner which will presently be explained. the armature of the relay oscillates between two stops whose distance apart is capable of fine adjustment. it is clear, therefore, that the impulse is independent of the strength of the current in the relay, provided that the armature is brought up to the stop on either side. the reversal of the current is effected by means of a small magnet carried by the bob of the pendulum, and which as it passes underneath the point of suspension is brought close to a soft iron armature, which has the form of an arc of a circle described about the point of suspension. this armature is pivoted at its center, and thus executes vibrations synchronously with those of the pendulum. these vibrations are adjusted to a very narrow range, but are sufficient to close the contacts of a commutator which reverses the current at each semi-vibration of the pendulum. the beauty and ingenuity of this device will readily be appreciated. * * * * * dr. morell mackenzie. the name of the great english laryngologist, which has long been honored by scientists of england and the continent, has lately become familar to everyone, even in unprofessional circles, in germany because of his operations on the crown prince's throat. if his wide experience and great skill enable him to permanently remove the growth from the throat of his royal patient, if his diagnosis and prognosis are confirmed, so that no fear need be entertained for the life and health of the crown prince, the english specialist will certainly deserve the most sincere thanks of the german nation. every phase of this treatment, every new development, is watched with suspense and hope. many have been unable to suppress the expression of regret that this important case was not under the care of a german, and part of the press look upon it as unjust treatment of the german specialists. but science is international, it knows no political boundaries, and the choice of dr. mackenzie by the family of the crown prince, whose sympathy with england is natural, cannot be considered a slight to german physicians when it is taken into consideration that the german authorities pronounced the growth suspicious and advised a difficult and doubtful operation, and that prof. v. bergman recommended that a foreign authority be consulted. as dr. mackenzie removed the obstruction, which had already become threatening and, in fact, dangerous, causing a loss of voice, and promised to remove any new growth from the inside without danger to the patient, the crown prince naturally trusted him. since virchow has made a microscopic examination of the part which was cut away, and has declared the new growth to be benign, all germans should watch the results of dr. mackenzie's operations with sympathy, trusting that all further growth will be prevented, and that the crown prince will be restored to the german people in his former state of health. [illustration: dr. morell mackenzie.] dr. morell mackenzie has lately reached his fiftieth year, and has attained the height of his fame as an author and practitioner. he was born at leytonston in , and studied first in london. at the age of twenty-two he passed his examination, then practiced as physician in the london hospital, and obtained his degree in . a year later he received the jackson prize from the royal society of surgeons for his treatment of a laryngeal case. he completed his studies in paris, vienna (with siegmund), and budapest. in the latter place he worked with czermak, making a special study of the laryngoscope. later he published an excellent work on "diseases of the throat and nose," which was the fruit of twelve years' work. the evening before the day on which this work was to have been issued, the whole edition was destroyed by a fire which occurred in the printing establishment, and had to be reprinted from the proof sheets, which were saved. in his work "on growths in the throat" appeared, and he has also published many articles in the _british medical journal_, the _lancet_, _medical times and gazette_, etc., which have been translated into different languages, making his name renowned all over europe. since he founded the first english hospital for diseases of the throat and chest, in london in , and held the position of lecturer on diseases of the throat in the london medical college, his career has been watched with interest by the public, and his practice in england is remarkable. therefore it is no wonder that his lately published work "on the hygiene of the vocal organs" has reached its fourth edition already. this work is read not only by physicians, but also by singers and lecturers. as a learned man in his profession, as an experienced diagnostician, and as a skillful and fortunate practitioner, he is surpassed by none; and his ability will be well known far beyond the borders of great britain if fortune favors him and he restores the future emperor of germany to his former strength and vigor, without which we cannot imagine this knightly form. the certainty with which dr. mackenzie speaks of permanent cures which he has effected in similar cases, together with the clear and satisfactory report of the great pathologist virchow, lead us to look to the future with confidence.--_illustrirte zeitung._ * * * * * hypnotism in france.[ ] [footnote : translated for _science_ from _der spinx_.] the voluntary production of those abnormal conditions of the nerves which to-day are denoted by the term "hypnotic researches" has manifested itself in all ages and among most of the nations that are known to us. within modern times these phenomena were first reduced to a system by mesmer, and, on this account, for the future deserve the attention of the scientific world. the historical description of this department, if one intends to give a connected account of its development, and not a series of isolated facts, must begin with a notice of mesmer's personality, and we must not confound the more recent development of our subject with its past history. the period of mesmerism is sufficiently understood from the numerous writings on the subject, but it would be a mistake to suppose that in braid's "exposition of hypnotism" the end of this subject had been reached. in a later work i hope to show that the fundamental ideas of biomagnetism have not only had in all periods of this century capable and enthusiastic advocates, but that even in our day they have been subjected to tests by french and english investigators from which they have issued triumphant. the second division of this historical development is carried on by braid, whose most important service was emphasizing the subjectivity of the phenomena. without any connection with him, and yet by following out almost exactly the same experiments, professor heidenhain reached his physiological explanations. a third division is based upon the discovery of the hypnotic condition in animals, and connects itself to the _experimentum mirabile_. in the first writings on this subject appear from the pen of the physiologist czermak; and since then the investigations have been continued, particularly by professor preyer. while england and germany were led quite independently to the study of the same phenomena, france experienced a strange development, which shows, as nothing else could, how truth everywhere comes to the surface, and from small beginnings swells to a flood which carries irresistibly all opposition with it. this fourth division of the history of hypnotism is the more important, because it forms the foundation of a transcendental psychology, and will exert a great influence upon our future culture; and it is this division to which we wish to turn our attention. we have intentionally limited ourselves to a chronological arrangement, since a systematic account would necessarily fall into the study of single phenomena, and would far exceed the space offered to us. james braid's writings, although they were discussed in detail in littré and robin's "lexicon," were not at all the cause of dr. philips' first books, who therefore came more independently to the study of the same phenomena. braid's theories became known to him later by the observations made upon them in béraud's "elements of physiology" and in littré's notes in the translation of müller's "handbook of physiology;" and he then wrote a second brochure, in which he gave in his allegiance to braidism. his principal effort was directed to withdrawing the veil of mystery from the occurrences, and by a natural explanation relegating them to the realm of the known. the trance caused by regarding fixedly a gleaming point produces in the brain, in his opinion, an accumulation of a peculiar nervous power, which he calls "electrodynamism." if this is directed in a skillful manner by the operator upon certain points, it manifests itself in certain situations and actions that we call hypnotic. beyond this somewhat questionable theory, both books contained a detailed description of some of the most important phenomena; but with the practical meaning of the phenomena, and especially with their therapeutic value, the author concerned himself but slightly. just on account of this pathological side, however, a certain attention has been paid to hypnotism up to the present time. in the year two surgeons in poictiers, drs. ribaut and kiaros, employed hypnotism with great success in order to make an operation painless. "this long and horrible work," says a journal of the day, "was much more like a demonstration in a dissecting room than an operation performed upon a living being." although this operation produced such an excitement, yet it was twelve years later before decisive and positive official intelligence was given of these facts by broca, follin, velpeau, and guérinau. but these accounts, as well as the excellent little book by dr. azam, shared the fate of their predecessors. they were looked upon by students with distrust, and by the disciples of mesmer with scornful contempt. the work of demarquay and giraud teulon showed considerable advance in this direction. the authors, indeed, fell back upon the theory of james braid, which they called stillborn, and of which they said, "_elle est restée accrochée en route_;" but they did not satisfy themselves with a simple statement of facts, as did gigot suard in his work that appeared about the same time. through systematic experiments they tried to find out where the line of hypnotic phenomena intersected the line of the realm of the known. they justly recognized that hypnotism and hysteria have many points of likeness, and in this way were the precursors of the present parisian school. they say that from magnetic sleep to the hypnotic condition an iron chain can be easily formed from the very same organic elements that we find in historical conditions. at the same time, as if to bring an experimental proof of this assertion, lasigue published a report on catalepsy in persons of hysterical tendencies, which be afterward incorporated into his larger work. among his patients, those who were of a quiet and lethargic temperament, by simply pressing down the eyelids, were made to enter into a peculiar state of languor, in which cataleptic contractions were easily produced, and which forcibly recalled hypnotic phenomena. "one can scarcely imagine," says the author, "a more remarkable spectacle than that of a sick person sunk in deep sleep, and insensible to all efforts to arouse him, who retains every position in which he is placed, and in it preserves the immobility and rigidity of a statue." but this impulse also was in vain, and in only a few cases were the practical tests followed up with theoretical explanations. unbounded enthusiasm and unjust blame alike subsided into a silence that was not broken for ten years. then charles richet, a renowned scientist, came forward in , impelled by the duty he felt he owed as a priest of truth, and made some announcements concerning the phenomena of somnambulism; and in countless books, all of which are worthy of attention, he has since then considered the problem from its various sides. he separates somnambulism into three periods. the word here is used for this whole class of subjects as richet himself uses it, viz., _torpeur_, _excitation_, and _stupeur_. in the first, which is produced by the so-called magnetic passes and the fixing of the eyes, silence and languor come over the subject. the second period, usually produced by constant repetition of the experiment, is characterized chiefly by sensibility to hallucination and suggestion. the third period has as its principal characteristics supersensibility of the muscles and lack of sensation. yet let it be noticed that these divisions were not expressed in their present clearness until ; while in the years between and , from an entirely different quarter, a similar hypothesis was made out for hypnotic phenomena. jean martin charcot, the renowned neurologist of the parisian salpetriere, without exactly desiring it, was led into the study of artificial somnambulism by his careful experiments in reference to hysteria, and especially by the question of _metallotherapie_, and in the year had prepared suitable demonstrations, which were given in public lectures at the salpetriere. in the following years he devoted himself to closer investigation of this subject, and was happily and skillfully assisted by dr. paul richer, with whom were associated many other physicians, such as bourneville, regnard, fere, and binet. the investigations of these men present the peculiarity that they observe hypnotism from its clinical and nosographical side, which side had until now been entirely neglected, and that they observe patients of the strongest hysterical temperaments. "if we can reasonably assert that the hypnotic phenomena which depend upon the disturbance of a regular function of the organism demand for their development a peculiar temperament, then we shall find the most marked phenomena when we turn to an hysterical person." the inferences of the parisian school up to this time are somewhat the following, but their results, belonging almost entirely to the medical side of the question, can have no place in this discussion. they divide the phenomena of hystero-hypnotism, which they also call _grande hysterie_, into three plainly separable classes, which charcot designates catalepsy, lethargy, and somnambulism. catalepsy is produced by a sudden sharp noise, or by the sight of a brightly gleaming object. it also produces itself in a person who is in a state of lethargy, and whose eyes are opened. the most striking characteristic of the cataleptic condition is immobility. the subject retains every position in which he is placed, even if it is an unnatural one, and is only aroused by the action of suggestion from the rigor of a statue to the half life of an automaton. the face is expressionless and the eyes wide open. if they are closed, the patient falls into a lethargy. in this second condition, behind the tightly closed lids, the pupils of the eyes are convulsively turned upward. the body is almost entirely without sensation or power of thought. especially characteristic of lethargy is the hyper-excitability of the nerves and muscles (_hyperexcitabilite neuromusculaire_), which manifests itself at the slightest touch of any object. for instance, if the extensor muscles of the arm are lightly touched, the arm stiffens immediately, and is only made flexible again by a hard rubbing of the same muscles. the nerves also react in a similar manner. the irritation of a nerve trunk not only contracts all the small nerves into which it branches, but also all those muscles through which it runs. finally, the somnambulistic condition proceeds from catalepsy or from lethargy by means of a slight pressure upon the _vertex_, and is particularly sensitive to every psychical influence. in some subjects the eyes are open, in others closed. here, also, a slight irritation produces a certain amount of rigor in the muscle that has been touched, but it does not weaken the antagonistic muscle, as in lethargy, nor does it vanish under the influence of the same excitement that has produced it. in order to put an end to the somnambulistic condition, one must press softly upon the pupil of the eye, upon which the subject becomes lethargic, and is easily roused by breathing upon him. in this early stage, somnambulism appears very infrequently. charcot's school also recognize the existence of compound conditions, the history of whose symptoms we must not follow here. these slightly sketched results, as well as a number of other facts, were only obtained in the course of several years; yet in the fundamental investigations of this school were considered virtually concluded. then dumont-pallier, the head of the parisian hospital pitié, came forward with a number of observations, drawn also exclusively from the study of hystero-hypnotism, and yet differing widely from those reached by the physicians of the salpetriere. in a long series of communications, he has given his views, which have in their turn been violently attacked, especially by magnin and bérillon. i give only the most important points. according to these men, the hyper-excitability of the nerves and muscles is present not only in the lethargic condition, but in all three periods; and in order to prove this, we need only apply the suitable remedy, which must be changed for each period and every subject. slight irritations of the skin prove this most powerfully. a drop of warm water or a ray of sunshine produces contractions of a muscle whose skin covering they touch. dumont-pallier and magnin accede to the theory of intermediate stages, and have tried to lay down rules for them with as great exactness as charcot's school. they also are very decided about the three periods, whose succession does not appear to them as fixed; but they discovered a new fundamental law which regulates the production as well as the cessation of the condition--_la cause qui fait, defait_; that is, the stimulus which produces one of the three periods needs only to be repeated in order to do away with that condition. from this the following diagram of hypnotic conditions is evolved: [illustration] and, furthermore, dumont-pallier should be considered as the founder of a series of experiments, for he was the first one to show in a decisive manner that the duality of the cerebral system was proved by these hypnotic phenomena; and his works, as well as those of messrs. bérillon and descourtis, have brought to light the following facts: under hypnotic conditions, the psychical activity of a brain hemisphere may be suppressed without nullifying the intellectual activity or consciousness. both hemispheres may be started at the same time in different degrees of activity; and also, when the grade is the same, they may be independently the seat of psychical manifestations which are in their natures entirely different. in close connection with this and with the whole doctrine of hemi-hypnotism, which is founded upon these facts, stand the phenomena of thought transference, which we must consider later. as an addition to the investigations of charcot and dumont-pallier, brémaud, in , made the discovery that there was a fourth hypnotic state, "fascination," which preceded the three others, and manifested itself by a tendency to muscular contractions, as well as through sensitiveness to hallucination and suggestion, but at the same time left to the subject a full consciousness of his surroundings and remembrance of what had taken place. descourtis, in addition, perceived a similar condition in the transition from hypnotic sleep to waking, which he called _delire posthypnotique_, and, instead of using the word "fascination" to express the opening stage, he substituted "captation." according to him, the diagram would be the following: [illustration] this whole movement, which i have tried to sketch, and whose chief peculiarity is that it considers hypnotism a nervous malady, and one that must be treated clinically and nosographically, was opposed in in two directions--one source of opposition producing great results, while the other fell to the ground. the latter joined itself to the theory of the mesmerists, and tried, by means of exact experiments, to measure the fluid emanating from the human body--an undertaking which gave slight promise of any satisfactory result. baillif in his thesis ( ) and chevillard in his (for spiritualists) very interesting books, tried, by means of various arguments, to uphold the fluidic explanation. despine also thought that by its help he had been able to explain the phenomena; but it was baréty who, in the year , first turned general attention in this direction. according to him, mankind possesses a nerve force which emanates from him in different kinds of streams. those coming from the eyes and fingers produce insensibility to pain, while those generated by the breath cause hypnotic conditions. this nerve force goes out into the ether, and there obeys the laws that govern light, being broken into spectra, etc. claude perronnet has more lately advanced similar views, and his greatest work is now in press. frederick w.h. myers and edmund gurney sympathize with these views, and try to unite them with the mesmerist doctrine of personal influence and their theory of telepathy. the third champion in england of hypnotism, prof. hack tuke, on the contrary, sympathizes entirely with the parisian school, only differing from them in that he has experimented with satisfactory results upon healthy subjects. in france this view has lately been accepted by dr. bottey, who recognizes the three hypnotic stages in healthy persons, but has observed other phenomena in them, and vehemently opposes the conception of hypnotism as a malady. his excellently written book is particularly commended to those who wish to experiment in the same manner as the french investigator, without using hysterical subjects. the second counter current that opposed itself to the french neuropathologists, and produced the most lasting impression, is expressed by the magic word "suggestion." a generation ago, dr. liebault, the patient investigator and skillful physician, had endeavored to make a remedial use of suggestion in his clinic at nancy. charles richet and others have since referred to it, but professor bernheim was the first one to demonstrate its full significance in the realm of hypnotism. according to him, suggestion--that is, the influence of any idea, whether received through the senses or in a hypersensible manner (_suggestion mentale_)--is the key to all hypnotic phenomena. he has not been able in a single case to verify the bodily phenomena of _grandehypnotisme_ without finding suggestion the primary cause, and on this account denies the truth of the asserted physical causes. bernheim says that when the intense expectance of the subject has produced a compliant condition, a peculiar capacity is developed to change the idea that has been received into an action as well as a great acuteness of acceptation, which together will produce all those phenomena that we should call by the name of "pathological sleep," since they are only separable in a gradual way from the ordinary sleep and dream conditions. bernheim is particularly strenuous that psychology should appear in the foreground of hypnotism, and on this point has been strongly upheld by men like professors beaunis and richet. the possibility of suggestion in waking conditions, and also a long time after the sleep has passed off (_suggestions posthypnotiques ou suggestions a (longue) echeance_), as well as the remarkable capacity of subjects to change their personality (_changement de la personnalite objectivation des types_), have been made the subject of careful investigation. the voluntary production of bleeding and stigmata through spiritual influence has been asserted, particularly by messrs. tocachon, bourru, and burot. the judicial significance of suggestion has been discussed by professor liegeois and dr. ladame. professor pitres in bordeaux is one of the suggestionists, though differing in many points from the nancy school. this whole tendency brings into prominence the psychical influence, while it denies the production of these results from purely physical phenomena, endeavoring to explain them in a different manner. these explanations carry us into two realms, the first of which has been lately opened, and at present seems to abound more in enigmas than in solutions. _metallotherapie_, which was called into existence by dr. burg, and further extended by dr. gellé, contains a special point of interest--the so-called transference in the case of hysterically or hypnotically affected persons. transference is caused by electro-magnetism, which has this peculiarity--that in the case of specially sensitive persons it can transfer the bodily affection from left to right, and _vice versa_. the transference of paralysis, the cures attempted on this plan, and the so-called "psychical transference," which contains special interest for graphologists, are at the present time still open questions, as well as the closely connected theory of human polarity; and the odic experiments of dr. chazarain are yet waiting for their confirmation. at present the problem of the connection between magnetism and hypnotism is under investigation, and in such a manner that we may hope for a speedy solution. still stranger than these reports are the accounts of the distant operation of certain bodies; at least, they seem strange to those unacquainted with psychometry and the literature of the past century relating to this subject. two physicians in rochefort, professors bourru and burot, in treating a hystero-epileptic person, found that gold, even when at a distance of fifteen centimeters, produced in him a feeling of unbearable heat. they continued these experiments with great care, and, after a number of trials, came to this conclusion--that in some persons certain substances, even when carefully separated from them by long distance, exercise exactly the same physiological influence as if introduced into their organism. in order to explain these phenomena, they refer to the radiating force of baréty, an explanation neither satisfactory to themselves nor to others. lately the distinguished parisian physician, dr. luys, has confirmed by his experiments the existence of these phenomena, but he thinks the explanation referable to hyper-sensitiveness of the "_regions emotives et intellectuelles de l'encephale_" yet even he has not reached the kernel of the difficulty. in close connection with action at a distance is the question of distant production of hypnotic sleep. for an answer to this problem, they are experimenting in both france and england; and frederick w.h. myers has thrown an entirely new light upon the subject by the investigations he is making upon a purely experimental basis. in italy they have limited themselves to the study of isolated cases of hystero-hypnotism, except as the phenomena of magnetic fascination investigated by donato have given rise to further research; but all the books i have seen upon this subject, as well as many by french authors, suffer from ignorance of the latest english discoveries. with this i think that i have given a slight outline of the history of hypnotic investigation to the end of the year . i shall attempt a criticism of this whole movement at some other time, as space is not afforded to me here; but i should like to make this statement now, that two of the characteristic indications of this period are of the gravest import--first the method ("our work," says richet, "is that of strictly scientific _testing_, _observation_, and _arrangement_"); and, secondly, the result. hypnotism has been received into the realm of scientific investigation, and with this the foundation of a true experimental psychology has been laid. max dessoir. * * * * * the duodenum: a siphon trap. by mayo collier, m.s. lond., f.r.c.s. eng.; senior assistant surgeon, north-west london hospital; assistant demonstrator of anatomy, london hospital medical college. we may take it for granted that all gases generated in the jejunum, ileum, and large intestines pass onward toward the anus, and there sooner or later escape. fetid gases--except those generated in the stomach and duodenum--never pass upward, not even during vomiting due to hernia, obstruction, and other causes. physiologists, it would appear, have never busied themselves to find an explanation for this apparent breach of the laws of gravity. the intestinal canal is a tube with various dilatations and constrictions, but at no spot except the pylorus does the constriction completely obliterate the lumen of the tube, and here only periodically. it is perfectly evident, then, that, unless some system of trap exists in the canal, gases are free to travel from below upward in obedience to the laws of gravity, and would, as a matter of fact, sooner or later do so. from the straight, course and vertical position of the oesophagus, a very slight pressure of gas in the stomach easily overcomes the closure of its cardiac sphincter and allows of escape. when the stomach has digested its contents and the pylorus is relaxed, gases generated in the duodenum can and do ascend into the stomach and so escape. normally, no fetid gases are generated in the stomach or duodenum. if we follow the course of the intestines down, we find that the duodenum presents a remarkable curve. now, there are some points of great interest in connection with this remarkable, almost circular, curve of the duodenum. in the first place, this curve is a constant feature in all mammalians. mr. treves says it is one of the most constant features in the anatomy of the intestines in man, and, speaking of mammalians in general, that the curve of the duodenum varies in shape, but is never absent, becoming more complex in some of the higher primates, but seldom less distinct than in man. in birds the duodenum always forms a long loop embracing the pancreas. a second point of great interest is the absolute constancy and fixation of its terminal portion at the point of junction with the jejunum, more correctly termed second ascending or fourth portion. mr. treves says that this fourth portion is never less than an inch, and is practically constant. it extends along the side of the left crus of the diaphragm opposite the second lumbar vertebra, and is there firmly fixed to the front of the aorta and crus of the diaphragm by a strong fibro-muscular band, slinging it up and absolutely retaining it in position. this band has been termed the "musculus suspensorius duodeni," but is chiefly composed of white fibrous tissue, and is more of the native of a ligament than a muscle. this ligament is always present, and its position is never altered. the curve of the duodenum may descend as far as the iliac fossa, but the terminal portion is always maintained by this band in its normal position. another point of great constancy is the position of the pancreas and its relation to the curve of the duodenum. the duodenum always curves round the head of the pancreas and is, as it were, moulded on it and retained in position by it. in birds the duodenum always forms a long loop embracing the pancreas. further, the ducts of the liver and pancreas always open into the center of the duodenum, either separately or by a common opening. [illustration] now, the absolute constancy of the curve of the duodenum, the complete fixation of its fourth portion, the position of the pancreas, and the place of entry of the ducts of the pancreas and liver, are all component parts of a siphon trap, whereby gases generated below the duodenum are prevented from passing upward. a reference to the accompanying diagrams will make this quite clear. a is a diagram of a siphon trap copied from parkes' hygiene. b is a very diagrammatic outline of the stomach and duodenum, _a_ is intended to mark the position of the fibrous band, or musculus suspensorius duodeni; and _b_ the position of entry of the ducts of the liver and pancreas. the duodenum, then, is a siphon trap, and a most efficient one. now, the efficiency of a siphon trap depends not only on its shape, but what is absolutely essential is that the curve must be kept constantly full of fluid, without which it ceases to be a trap, and would allow gases to ascend freely. the position of the place of entry of the ducts of the pancreas and liver assures that this _sine qua non_ shall be present. the discharge of the secretions of the pancreas and liver, although more active during and after feeding, is practically constant, and so insures in an admirable manner that the curve on which the efficiency of the trap depends shall be constantly kept full not only with fluid, but, as i would suggest, antiseptic fluid. there is no other trap in the intestinal canal, but the peculiar position of the colon would no doubt have more or less effect in preventing gases ascending through the ileo-cæcal valve.--_lancet._ * * * * * wisconsin cranberry culture. among the many thousands of well informed persons with whom the cranberry is a staple article of food throughout the autumn and winter, and who especially derive from its pungent flavor sharp relish for their thanksgiving and christmas turkey, not one in ten has any definite idea as to where the delicious fruit comes from, or of the method of growing and harvesting it. most people are, however, aware that it is raised on little "truck patches" somewhere down in new jersey or about cape cod, and some have heard that it is gleaned from the swamps in the far west by indians and shipped to market by white traders. but to the great majority its real history is unknown. yet the cranberry culture is an industry in which millions of dollars are invested in this country, and it gives employment, for at least a portion of each year, to many thousands of people. in the east, where the value of an acre of even swamp land may run up into the thousands of dollars, a cranberry marsh of five or ten acres is considered a large one, and, cultivated in the careful, frugal style in vogue there, may yield its owner a handsome yearly income. but in the great, boundless west, where land, and more especially swamp land, may be had for from $ to $ an acre, we do these things differently, if not better. the state of wisconsin produces nearly one-half of the cranberries annually grown in the united states. there are marshes there covering thousands of acres, whereon this fruit grows wild, having done so even as far back as the oldest tradition of the native red man extends. in many cases the land on which the berries grow has been bought from the government by individuals or firms, in vast tracts, and the growth of the fruit promoted and encouraged by a system of dikes and dams whereby the effects of droughts, frost, and heavy rainfalls are counteracted to almost any extent desired. some of these holdings aggregate many thousands of acres under a single ownership; and after a marsh of this vast extent has been thoroughly ditched and good buildings, water works, etc., are erected on it, its value may reach many thousands of dollars, while the original cost of the land may have been merely nominal. large portions of jackson, wood, monroe, marinette, juneau, and green counties are natural cranberry marshes. the wisconsin valley division of the chicago, milwaukee & st. paul railway runs through a closely continuous marsh, forty miles long and nearly as wide, as level as a floor, which is an almost unbroken series of cranberry farms. the indians, who inhabited this country before the white man came, used to congregate here every fall, many of them traveling several hundred miles, to lay in their winter supply of berries. many thousands of barrels are now annually shipped from this region; and thus this vast area, which to the stranger looking upon it would appear utterly worthless, is as valuable as the richest farming lands in the state. in a few instances, however, this fruit is cultivated in wisconsin in a style similar to that practiced in the east; that is, by paring the natural sod from the bog, covering the earth to a depth of two or three inches with sand, and then transplanting the vines into soil thus prepared. the weeds are then kept down for a year or two, when the vines take full possession of the soil, and further attention is unnecessary. the natural "stand" of the vines in the sod is so productive, however, and the extent of country over which bountiful nature has distributed them so vast, that few operators have thought it necessary to incur the expense of special culture. one of the best and most perfectly equipped marshes in wisconsin is owned by mr. g.b. sackett, of berlin. it is situated four miles north of that village, and comprises , acres, nearly all of which is a veritable bog, and is covered with a natural and luxuriant growth of cranberry vines. a canal has been cut from the fox river to the southern limit of the marsh, a distance of , ft. it is ft. wide, and the water stands in it to a depth of nine feet, sufficient to float fair sized steamboats. at the intersection of the canal with the marsh steam water works have been erected, with flood gates and dams by means of which the entire marsh may be flooded to a depth of a foot or more when desired. there are two engines of horse power each, and two pumps that are capable of raising , gallons per minute. when, in early autumn, the meteorological conditions indicate the approach of frost, the pumps may he put to work in the afternoon and the berries be effectually covered by water and thus protected before nightfall. at sunrise the gates are opened and the water allowed to run off again, so that the pickers may proceed with their work. the marsh is flooded to a depth of about two feet at the beginning of each winter and allowed to remain so until spring, the heavy body of ice that forms preventing the upheaval that would result from freezing and thawing--a natural process which, if permitted, works injury to the vines. there is a three-story warehouse on the marsh, with a capacity of , barrels of berries, and four large two-story houses capable of furnishing shelter for , pickers. the superintendent's residence is a comfortable cottage house, surrounded by giant oaks and elms, and stands near the warehouse on an "island," or small tract of high, dry land near the center of the great marsh. the pickers' quarters stand on another island about yards away. a plank roadway, built on piles, about two feet above the level of the ground, leads from the mainland to the warehouse and other buildings, a distance of more than half a mile. several wooden railways diverge from the warehouse to all parts of the marsh, and on them flat cars, propelled by hand, are sent out at intervals during the picking season to bring in the berries from the hands of the pickers. each picker is provided with a crate, holding just a bushel, which is kept close at hand. the berries are first picked into tin pans and pails, and from these emptied into the crates, in which they are carried to the warehouse, where an empty crate is given the picker in exchange for a full one. thus equipped and improved, the sackett marsh is valued at $ , . thirteen thousand barrels have been harvested from this great farm in a single season. the selling price in the chicago market varies, in different seasons, from $ to $ per barrel. there are several other marshes of various sizes in the vicinity. the picking season usually begins about sept. , and from that time until oct. the marshes swarm with men, women, and children, ranging in age from six to eight years, made up from almost every nationality under the sun. bohemians and poles furnish the majority of the working force, while germans, irish, swedes, norwegians, danes, negroes, indians, and americans contribute to the motley contingent. they come from every direction and from various distances, some of them traveling a hundred miles or more to secure a few days' or weeks' work. almost every farmer or woodsman living anywhere in the region of the marshes turns out with his entire family; and the families of all the laboring men and mechanics of the surrounding towns and cities join in the general hegira to the bogs, and help to harvest the fruit. those living within a few miles go out in the morning and return home at night, taking their noon-day meal with them, while those from a distance take provisions and bedding with them and camp in the buildings provided for that purpose by the marsh owners, doing their own cooking on the stoves and with the fuel furnished them. the wages vary from fifty cents to a dollar a bushel, owing to the abundance or scarcity of the fruit. a good picker will gather from three to four bushels a day where the yield is light, and five to six bushels where it is good. the most money is made by families numbering from half a dozen to a dozen members. every chick and child in such families over six years old is required to turn out and help swell the revenue of the little household, and the frugal father often pockets ten to twenty dollars a day as the fruits of the combined labors. the pickers wade into the grass, weeds, and vines, however wet with dew or rain, or however deeply flooded underneath, making not the slightest effort to keep even their feet dry, and after an hour's work in the morning are almost as wet as if they had swum a river. many of them wade in barefooted, others wearing low cowhide shoes, and their feet, at least, are necessarily wet all day long. in many cases their bodies are thinly clad, and they must inevitably suffer in frosty mornings and evenings and on the raw, cold, rainy days that are frequent in the autumn months in this latitude; yet they go about their work singing, shouting, and jabbering as merrily as a party of comfortably clad school children at play. how any of them avoid colds, rheumatism, and a dozen other diseases is a mystery; and yet it is rarely that one of them is ill from the effects of this exposure. as many as or pickers are sometimes employed on a single marsh when there is a heavy crop, and an army of such ragamuffins as get together for this purpose, scattered over a bog in confusion and disorder, presents a strange and picturesque appearance. indians are not usually as good pickers as white people, but in the sparsely settled districts, where many of the berry farms are situated, it is impossible to get white help enough to take care of the crop in the short time available for the work, and owners are compelled to employ the aborigines. a rake, with the prongs shaped like the letter v, is used for picking in some cases, but owing to the large amount of grass and weeds that grow among the vines on these wild marshes, this instrument is rarely available. after being picked the berries are stored in warehouses for a period varying from one to three weeks. they are washed and dried by being passed through a fanning mill made for the purpose, and are then allowed to cure and ripen thoroughly before they are shipped to market. from statistics gathered by the american cranberry growers' association it is learned that in wisconsin produced , bushels, in , bushels, in , bushels, and in , bushels of this fruit. by these figures it will be seen that the yield is very irregular. this is owing, principally, to the fact that many of the marshes are not yet provided with the means of flooding, and of course suffer from worms, droughts, late spring or early autumn frosts, and extensive fires started by sparks from the engines on railroads running through the marshes. these and various other evils are averted on the more improved farms. so that, while handsome fortunes have in many cases been made in cranberry growing, many thousands of dollars have, on the other hand, been sunk in the same industry. only the wealthier owners, who have expended vast sums of money in improving and equipping their property, can calculate with any degree of certainty on a paying crop of fruit every year. chicago is the great distributing point for the berries produced in wisconsin, shipments being made thence to nearly every state and territory in the union, to canada, to mexico, and to several european countries. berries sent to the southern markets are put up in watertight packages, and the casks are then filled with water, this being the only means by which they can be kept in hot weather. even in this condition they can only be kept a few days after reaching hot climates.--_american magazine._ * * * * * soudan coffee. (_parkia biglobosa._) there are valuable plants on every continent. civilized europe no longer counts them. mysterious africa is no less largely and spontaneously favored with them than young america and the ancient territory of asia. the latter has given us the majority of the best fruits of our gardens. we have already shown how useful the butter tree (_butyrospermum parkii_) is in tropical africa, and we also know how the _gourou_ (_sterculia acuminata_) is cultivated in the same regions. but that is not all, for the great family of leguminosæ, whose numerous representatives encumber this continent, likewise furnishes the negro natives a food that is nearly as indispensable to them as the _gourou_ or the products of the baobab--another valuable tree and certainly the most widely distributed one in torrid africa. this leguminous tree, which is as yet but little known in the civilized world, has been named scientifically _parkia biglobosa_ by bentham. the negroes give it various names, according to the tribe; among the ouloffs, it is the _houlle_; among the mandigues, _naytay_; in cazamance (nalon language), it is _nayray_; in bornou, _rounuo_; in haoussa, _doroa_; in hant-fleure (senegal), _nayraytou_. on the old mysterious continent it plays the same role that the algarobas do in young america. however, it is quite a common rule to find in the order leguminosæ, and especially in the section mimosæ, plants whose pods are edible. examples of this fact are numerous. as regards the mediterranean region, it suffices to cite the classic carob tree (_ceratonia siliqua_), which also is of african nationality, but which is wanting in the warm region of this continent. throughout the tropical region of africa, the aborigines love to consume the saccharine pulp and the seed contained in the pod of the _houlle_. prepared in different ways, according to tribe and latitude, these two products constitute a valuable aliment. the pulp is consumed either just as it is or as a fermented beverage. as for the seeds, they serve, raw or roasted, for the production of a tea-like infusion (whence the name "soudan coffee"), or, after fermentation in water, for making a national condiment, which in certain places is called _kinda_, and which is mixed with boiled rice or prepared meats. this preparation has in most cases a pasty form or the consistency of cohesive flour; but in order to render its carriage easier in certain of the african centers where the trade in it is brisk, it is compressed into tablets similar to those of our chocolate. as these two products are very little known in europe, it has seemed to us that it would be of interest to give a description and chemical analysis of them. we shall say but little of the plant, which has sufficiently occupied botanists. [illustration: figs. to .--pods of the houlle and microscopic details.] the houlle (_parkia biglobosa_) is a large tree from to feet in height, with a gray bark, many branches, and large, elegant leaves. the latter are compound, bipinnate (fig. ), and have fifty pairs of leaflets, which are linear and obtuse and of a grayish green. the inflorescence is very pleasing to the eye. the flowers, say the authors of the _floræ senegambiæ tentamen_, form balls of a dazzling red, contracted at the base, and resembling the pompons of our grenadiers (fig. ). the support of this latter consists only of male flowers. the fruit that succeeds these flowers is supported by a club-shaped receptacle. it consists of a large pod, which at maturity is inches in length by in width (fig. ). this pod is chocolate brown, quite smooth or slightly tubercular, and is swollen at the points where the seeds are situated. the pods are straight or slightly curved. the aborigines of rio nunez use the pods for poisoning the fishes that abound in the watercourses. we do not know what the nature of the toxic principle is that is contained in these hard pods, but we well know the nature of the yellowish pulp and of the seeds that entirely fill the pods. [illustration: fig. .--parkia biglobosa.] although the pulp forms a continuous whole, each seed easily separates from the following and carries with it a part of the pulp that surrounds it and that constitutes an independent mass (fig. ). this pulpy substance, formed entirely of oval cells filled with aleurone, consists of two distinct layers. the first, an external one of a beautiful yellow, is from to times bulkier than the internal one, which likewise is of a beautiful yellow. [illustration: fig. --flowers of parkia.] it detaches itself easily from the seed, while the internal layer, which adheres firmly to the exterior of the seed, can be detached only by maceration in water. this fresh pulp has a sweet and agreeable although slightly insipid taste. upon growing old and becoming dry, it takes on a still more agreeable taste, for it preserves its sweetness and gets a perfume like that of the violet. as for the seed, which is of a brown color and provided with a hard, shining skin, that is . inch long, . inch wide, and . inch thick. it is oval in form, with quite a prominent beak at the hilum (fig. ). the margin is blunt and the two convex sides are provided in the center with a gibbosity limited by a line parallel with the margin, and this has given the plant its specific name of _biglobosa_. the mean weight of each seed is ½ grains. the skin, though thick, is not very strong. it consists, anatomically, of four layers (fig. ) of a thick cuticle, _c_; of a zone of palissade cells, _z p_; of a zone of cells with thick tangential walls arranged in a single row; and of a zone tougher than the others, formed of numerous cells with thick walls, without definite form, and filled with a blackish red coloring matter, _cs_. this perisperm covers an exalbuminous embryo formed almost entirely of two thick, greenish yellow cotyledons having a strong taste of legumine. when examined under the microscope, these cotyledons, the alimentary part of the seed, have the appearance represented in fig. , where _ep_ is the epidermic layer and _cp_ constitutes the uniform parenchyma of the cotyledonary leaf. this parenchymatous mass consists of oval cells filled with fatty matter and granules of aleurone. according to some chemical researches made by professor schlagdenhauffen, the pulp has the following composition per parts: fatty matter . glucose . inverted sugar . coloring matter and free acids . albuminous matter . gummy matter . cellulose . lignose . salts . ------- total . the salient point of these analytical results is the enormous quantity of matter (nearly per cent.) formed almost exclusively by sugar. it is not surprising, from this that this product constitutes a food both agreeable and useful. an analysis of the entire seed, made by the same chemist, has given the following results: solid fatty matter . unreduced sugar . undetermined matters . gummy " . albuminoid " . cellulosic " . lignose and losses . salts . ------- total . the presence in these seeds of a large quantity of fatty matters and sugar, and especially of albuminoid matters (very nutritive), largely justifies the use made of them as a food. the innate instinct of the savage peoples of africa has thus anticipated the data of science.--_la nature._ * * * * * the height of summer clouds. a knowledge of the heights and movements of the clouds is of much interest to science, and of especial importance in the prediction of weather. the subject has therefore received much attention during recent years from meteorologists, chiefly in this country and in sweden. in the last published report of the meteorological council for - will be found an account of the steps taken by that body to obtain cloud photographs; and in the _meteorologische zeitschrift_ for march last, m.m. ekholm and hagstrom have published an interesting summary of the results of observations made at upsala during the summers of - . they determined the parallax of the clouds by angular measurements made from two stations at the extremities of a base of convenient length and having telephonic connection. the instruments used were altazimuths, constructed under the direction of prof. mohn, specially for measuring the parallax of the aurora borealis. a full description of these instruments and of the calculations will be found in the _acta reg soc. sc. ups._, . the results now in question are based upon nearly , measurements of _heights_; the _motions_ will form the subject of a future paper. it was found that clouds are formed at all levels, but that they occur most frequently at certain elevations or stages. the following are, approximately, the mean heights, in feet, of the principal forms: stratus, , ; nimbus, , ; cumulus (base) , , (summit) , ; cumulo-stratus (base), , ; "false-cirrus" (a form which often accompanies the cumulo-stratus), , ; cirro cumulus, , ; cirrus, , (the highest being , ). the maximum of cloud frequency was found to be at levels of , and , feet. generally speaking, all the forms of cloud have a tendency to rise during the course of the day; the change, excepting for the cumulus form, amounting to nearly , feet. in the morning, when the cirrus clouds are at their lowest level, the frequency of their lowest forms--the cirro-cumulus--is greatest; and in the evening, when the height of the cirrus is greatest, the frequency of its highest forms--the cirro-stratus--is also greatest. with regard to the connection between the character of the weather and the height of the clouds, the heights of the bases of the cumulus are nearly constant in all conditions. the summits, however, are lowest in the vicinity of a barometric maximum. they increase in the region of a depression, and attain their greatest height in thunderstorms, the thickness of the cumulo stratus stretching sometimes for several miles. the highest forms of clouds appear to float at their lowest levels in the region of a depression. the forms of clouds are identical in all parts of the world, as has been shown in papers lately read by the hon. r. abercromby before the english and scottish meteorological societies.--_nature_. * * * * * on the cause of iridescence in clouds. by g. johnstone stoney. when the sky is occupied by light cirro-cumulus cloud, an optical phenomenon of the most delicate beauty sometimes presents itself, in which the borders of the clouds and their lighter portions are suffused with soft shades of color like those of mother-of-pearl, among which lovely pinks and greens are the most conspicuous. usually these colors are distributed in irregular patches, just as in mother-of-pearl; but occasionally they are seen to form round the denser patches of cloud a regular colored fringe, in which the several tints are arranged in stripes following the sinuosities of the outline of the cloud. i cannot find in any of the books an explanation of this beautiful spectacle, all the more pleasing because it generally presents itself in delightful summer weather. it is not mentioned in the part of moigno's great _repertoire d'optique_ which treats of meteorological optics, nor in any other work which i have consulted. it seems desirable, therefore, to make an attempt to search out what appears to be its explanation. at the elevation in our atmosphere at which these delicate clouds are formed the temperature is too low, even in midsummer, for water to exist in the liquid state; and accordingly, the attenuated vapor from which they were condensed passed at once into a solid form. they consist, in fact, of tiny crystals of ice, not of little drops of water. if the precipitation has been hasty, the crystals will, though all small, be of many sizes jumbled together, and in that case the beautiful optical phenomenon with which we are now dealing will not occur. but if the opposite conditions prevail (which they do on rare occasions), if the vapor had been evenly distributed, and if the precipitation took place slowly, then will the crystals in any one neighborhood be little ice crystals of nearly the same form and size, and from one neighborhood to another they will differ chiefly in number and size, owing to the process having gone on longer or taken place somewhat faster, or through a greater depth, in some neighborhoods than others. this will give rise to the patched appearance of the clouds which prevails when this phenomenon presents itself. it also causes the tiny crystals, of which the cloud consists, to grow larger in some places than others. captain scoresby, in his "account of the arctic regions," gives the best description of snow crystals formed at low temperatures with which i am acquainted. from his observations it appears--(a) that when formed at temperatures several degrees below the freezing point, the crystals, whether simple or compound, are nearly all of symmetrical forms; (b) that thin tabular crystals are extremely numerous, consisting either of simple transverse slices of the fundamental hexagon or, more frequently, of aggregations of these attached edgewise and lying in one plane; and (c) that, according as atmospheric conditions vary, one form of crystal or another largely preponderates. a fuller account of these most significant observations is given in the appendix to this paper. let us then consider the crystals in any one neighborhood in the sky, where the conditions that prevail are such as to produce lamellar crystals of nearly the same thickness. the tabular plates are subsiding through the atmosphere--in fact, falling toward the earth. and although their descent is very slow, owing to their minute size, the resistance of the air will act upon them as it does upon a falling feather. it will cause them, if disturbed, to oscillate before they settle into that horizontal position which flat plates finally assume when falling through quiescent air. we shall presently consider what the conditions must be, in order that the crystals may be liable to be now and then disturbed from the horizontal position. if this occasionally happens, the crystals will keep fluttering, and at any one moment some of them will be turned so as to reflect a ray from the sun to the eye of the observer from the flat surface of the crystal which is next him. now, if the conditions are such as to produce crystals which are plates with parallel faces, and as they are also transparent, part only of the sun's ray that reaches the front face of the crystal will be reflected from it; the rest will enter the crystal, and, falling on the parallel surface behind, a portion will be there reflected, and passing out through the front face, will also reach the eye of the observer. these two portions of the ray--that reflected from the front face and that reflected from the back--are precisely in the condition in which they can interfere with one another, so as to produce the splendid colors with which we are familiar in soap bubbles. if the crystals are of diverse thicknesses, the colors from the individual crystals will be different, and the mixture of them all will produce merely white light; but if all are nearly of the same thickness, they will transmit the same color toward the observer, who will accordingly see this color in the part of the cloud occupied by these crystals. the color will, of course, not be undiluted; for other crystals will send forward white light, and this, blended with the colored light, will produce delicate shades in cases where the corresponding colors of a soap bubble would be vivid. we have now only to explain how it happens that on very rare occasions the colors, instead of lying in irregular patches, form definite fringes round the borders of the cloudlets. the circumstances that give rise to this special form of the phenomenon appear to be the following: while the cloud is in the process of growth (that is, so long as the precipitation of vapor into the crystalline state continues to take place), so long will the crystals keep augmenting. if, then, a cloudlet is in the process of formation, not only by the springing up of fresh crystals around, but also by the continued growth of the crystals within it, then will that patch of cloud consist of crystals which are largest in its central part, and gradually smaller as their situation approaches the outside. here, then, are conditions which will produce one color round the margin of the cloud, and that color mixed with others, and so giving rise to other tints, farther in. in this way there comes into existence that iris-like border which is now and then seen. the occasional upsetting of the crystals, which is required to keep them fluttering, may be produced in any of three ways. the cloudlets may have been formed from the blending together of two layers of air saturated at different temperatures, and moving with different velocities or in different directions. where these currents intermix, a certain amount of disturbance will prevail, which, if sufficiently slight, would not much interfere with the regularity of the crystals, and might yet be sufficient to occasion little draughts, which would blow them about when formed. or, if the cold layer is above, and if it is in a sufficient degree colder, there need not be any previous relative motion of the two layers; the inevitable convection currents will suffice. another, and probably the most frequent, cause for little breezes in the neighborhood of the cloudlets is that when the cloudlets are formed they immediately absorb the heat of the sun in a way that the previously clear air had not done. if they absorb enough, they will rise like feeble balloons, and slight return currents will travel downward round their margins, throwing all crystals in that situation into disorder. i do not include among the causes which may agitate the crystals another cause which must produce excessively slight currents of air, namely, that arising from the subsidence of the cloudlets owing to their weight. the crystals will fall faster wherein cloud masses than in the intervening portions where the cloud is thinner. but the subsidence itself is so slow that any relative motions to which differences in the rate of subsidence can give rise are probably too feeble to produce an appreciable effect. of course, in general, more than one of the above causes will concur; and it is the resultant of the effects which they would have separately produced that will be felt by the crystals. if the precipitation had taken place so very evenly over the sky that there were no cloudlets formed, but only one uniform veil of haze, then the currents which would flutter the crystals may be so entirely absent that the little plates of crystals can fixedly assume the horizontal position which is natural to them. in this event the cloud will exhibit no iridescence, but, instead of it, a vertical circle through the sun will present itself. this, on some rare occasions, is a feature of the phenomenon of parhelia. it thus appears that the occasional iridescence of cirrus clouds is satisfactorily accounted for by the concurrence of conditions, each of which is known to have a real existence in nature....--_phil. mag., july ._ * * * * * the scientific american architects and builders edition. $ . a year. single copies, cts. this is a special edition of the scientific american, issued monthly--on the first day of the month. each number contains about forty large quarto pages, equal to about two 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residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats, trade marks, their costs, and how procured. address munn & co., broadway, new york. branch office, and f st., washington, d.c. proofreading team at www.pgdp.net [illustration] scientific american supplement no. new york, december , . scientific american supplement. vol. xii., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. engineering and mechanics.--improved fifteen ton traveling crane. designed for service in the construction of port alfred harbor. south africa. figures. improved steam boiler. figure. the elevated railways of new york. some of the developments of mechanical engineering during the last half century. british association paper. by sir frederick bramwell. the steam engine.--evaporative condenser.--steam navigation.--marine governors.--light engines and boilers.--the perkins system.--ether engine.--quicksilver engine.--locomotive engines.--brakes.--motors.--transmission of power.--compressed air locomotives.--hydraulic transmission of power.--electric transmission of power.--the manufacture of iron and steel.-- bridges.--machine tools.--the sewing machine.--agricultural machinery.--printing machinery. amateur mechanics: metal turning, figures. rotary cutters, figures. wood-working and lathe attachments, figures. a new method of keeping mechanical drawings. achard's electric brake for railway use. figures. plan and elevation. ii. electricity, etc.--electricity. what it is and what may be expected of it. by jacob reese. electric light apparatus for photographic purposes. by a.j. jarman. figures. desruelles's electric lighter. figure. solenoid underground wires in philadelphia. dr. herz's telephonic systems. figures. decision of the congress of electricians on the units of electric measures. secondary batteries. by j. rousse. iii. technology and chemistry.--domestic sugar production. m. garnier's new methods of photo-engraving. by major j. waterhouse.--photogravure.--photograph printing by vapor.--atmography. dangers of pyrogallic acid. by dr. t.l. phipson. iv. architecture, etc.--artists' homes, no. .--wm. emerson's house, little sutton, chiswick.--full page illustration and large size longitudinal section. memorable english houses. figures.--newton's house.-- flaxman's house.--canning's house.--johnson's house. v. geography.--herald island.--on the summit.--a midnight observation.--plant life on herald island.--inhabitants of the cliffs. vi. metallurgy.--the treatment of quicksilver ores in spain. vii. aeronautics.--the balloon in aeronautics. viii. biography.--franz liszt.--large portrait. * * * * * improved fifteen ton crane. [illustration: engraving.] [illustration: side and top view plans. improved fifteen ton traveling crane.] the machine illustrated on first page has been constructed for port alfred harbor, this being one of several harbors now being made by sir j. coode in south africa. the pier for the construction of which the crane will be employed will consist of concrete blocks laid on what is known as the "overend system." the blocks, being brought on trucks direct from the block yard to within the sweep of the machine, are raised by it, swung round, and accurately set, the machine being continually traveled forward as the work advances. the bottom blocks are laid on bags of concrete previously deposited by the crane out of boxes with flap bottoms. the present machine has been specially designed throughout, and represents the most complete development which block-setting plant has yet attained. the most striking features of the crane are, the great range of all the motions, the large radius, and the method of providing for the latter by a horizontal jib suspended from a king-post. it was at first intended to have a straight inclined jib, and to alter the radius by pivoting this round its lower end, as is commonly done; it occurred, however, to mr. matthews, m.i.c.e., representing sir j. coode, that the plan eventually adopted would be in many ways preferable; the crane was therefore constructed by messrs. stothert & pitt with this modification, and as far as can be judged from the trial with proof load, the arrangements can hardly be surpassed for quick and accurate block-setting. in cranes with "derricking" jibs it is necessary to connect the derrick and hoisting gears in such a manner that a variation of the radius may not affect the level of the load; this plan answers sufficiently well for ordinary purposes, but for block-setting it is requisite to have extreme accuracy in all the movements and great quickness in changing from one to another; the arrangements adopted in foundry cranes, in which all the motions are entirely independent of one another, seems therefore more suited for this kind of work. other not inconsiderable advantages are also secured by the adoption of the foundry crane type, the amount of clear headway under the jib being much increased, and the difficulty avoided of making a jib sixty feet long sufficiently stiff without undue weight. the principal dimensions of the crane are, total height of lift feet, radius variable from feet minimum to feet maximum, height from rail to underside of jib feet ¾ inches, radius of tail to center of boiler feet, working load tons, proof load tons. the general arrangement consists of a truck on which is fixed a post, round which the crane revolves; the jib is supported midway by an inclined strut, above which is placed the king-post; the strut is curved round at the bottom and forms one piece with the side frames, which are carried right back as a tail to support the boiler and balance weight. the hoisting gear consists of a double system of chains / in. in diameter placed side by side; each chain is anchored by an adjustable screw to the end of the jib, and, passing round the traveling carriage and down to the falling block, is taken along the jib over a sliding pulley which leads it on to the grooved barrel, ft. in. in diameter. in front of the barrel is placed an automatic winder which insures a proper coiling of the chain in the grooves. the motive power is derived from two cylinders in. in diameter and in. stroke, one being bolted to each side frame; these cylinders, which are provided with link motion and reversing gear, drive a steel crank shaft ¾ in. in diameter; on this shaft is a steel sliding pinion which drives the barrel by a double purchase. in the center of the crank-shaft is a large reversing friction clutch, which drives, through miter gear, a vertical shaft placed just in front of the post; from the latter the slewing, racking, and traveling motions are obtained. the crane can be turned through a complete circle by a pinion gearing into a machine-moulded toothed ring bolted to the top of the truck; this ring is ft. - / in. in diameter, and contains teeth ½ in pitch. the slewing pinion is driven by intermediate gearing from the bottom of the vertical shaft mentioned above. for the turning motion two distinct sets of rollers are provided; these are carried by cross-girders placed between the side frames; one set runs against a cast-iron roller path bolted round the bottom of the post, and the other on the large horizontal roller path seen in the engraving. the latter is ft. in diameter; it is built up of two deep curved channel irons with top and bottom plates forming a circular box girder, on the top of which a heavy flat rail is riveted, and the whole turned up in the lathe. the racking and traveling motions are driven from the top end of the vertical shaft; the racking gear consists of wire ropes attached to each side of the traveling carriage and coiled round a large barrel, the outer rope being brought over a pulley at the end of the jib. the rails for the carriage rest on rolled joints bolted to the underside of jib. this arrangement involves the use of an overhung traveling carriage, but enables the jib to be of a stiff box section, the side stiffness being further secured by wind ties. the traveling motion is worked by a second vertical shaft, which passes down the center of the post, and by means of a cross shaft is geared to the front axle, from which four of the ground wheels are driven. the post is octagonal, built up of plates ¾ in. thick; at the bottom end it is secured to the girders of the truck, and at the top is shrunk on to a large gudgeon in. in diameter, which enters a casting fixed in the back end of the jib; on the top of the gudgeon are two steel disks on which an adjustable cap rests; by means of this and the ties to the tail and the lower end of the strut a proportion of the weight can be brought on to the post so as to relieve the roller path to any desired extent, and enable the crane to be revolved easily. the truck is ft. long and ft. ½ in. wide; it is constructed of longitudinal and transverse box girders ft. in. deep, and rests on two axles in. in diameter; round these axles swivel the cast-iron bogie frames which carry the ground wheels. this arrangement was adopted because the crane has to travel up a gradient of in , and the bogies enable it to take the incline better; they also distribute the weight more evenly on the wheels. the gauge of the rails is ft, the wheels are ft. in. in diameter, and have heavy steel tires. the weight on each of the front wheels when running with the ballast, but no load, is about tons. a powerful brake is applied to the wheels when descending the incline. all the clutch levers, break treadle, and handles are brought together, so that one man has the crane under his entire control. an iron house, of which the framing only is shown, extends from the gearing right back to the boiler, forming a most spacious engine room and stokehole. a separate donkey engine is provided for feeding the boiler. the truck is furnished with legs under which packings can be wedged so as to relieve the load on the wheels when block-setting. the slings seen under the boiler are for hanging a concrete balance weight; this will weigh about tons. the weight of the crane itself without load or ballast is about tons. the crane was tested under steam with a load of tons with the most satisfactory results; the whole machine appeared to be very rigid, an end often very difficult to obtain with portable wrought-iron structures and live loads. the result in the present case is probably greatly due to the careful workmanship, and to the fact that the sides and ends of the plates are planed throughout, so that the webs of the girders get a fair bearing on the top and bottom plates. the crane showed itself to be very handy and quick in working, the speeds with tons load, as actually timed at the trial, are: lifting ft. per minute, racking motion ft. per minute, slewing through a complete circle ft. diameter, four minutes, equivalent to a speed at load of ft. per minute. the crane was constructed by messrs. stothert & pitt, of bath, to the order of the crown agents for the colonies, and we understand that the design and construction have given complete satisfaction to sir j. coode, the engineer to the harbor works, under whose supervision the crane was constructed.--_engineering._ * * * * * improved steam-boiler. an improvement in steam-boilers, best understood by reference to the ordinary vertical form, has been introduced by mr. t. moy, london. here the flue is central, and, as shown in the accompanying illustration, is crossed by a number of horizontal water-tubes at different heights. the ends of these tubes are embraced, within the steam chamber, by annular troughs. at the top domed part of the boiler are two annular chambers, the outer one being intended to receive the water upon entry from the feed-pump, and to contain any sedimentary deposit which may be formed. the water next passes, by the pipe, _a_, in the figure, into the inner chamber, surrounding the end of the uptake flue, whence it flows through the pipe, _b_, down into the first of the annular troughs above mentioned, and afterward overflows these troughs in succession until it reaches the bottom. mr. moy claims to have secured by this means a boiler of quick steaming capacity, together with a reduction in the weight of metal, and considerable economy of fuel. by the arrangement of the water in a number of shallow layers a large steaming surface is obtained, and there is a good steam space rendered available round the troughs. the water also enters at a point where it may abstract as much heat as possible from the furnace gases before they escape; and by the separation of the top domed chamber from the rest of the boiler the operation of scaling and cleaning is facilitated. the arrangement is also adapted to horizontal and multitubular boilers, to be fired with solid, liquid, or gaseous fuel. [illustration: improved boiler.] * * * * * the elevated railways of new york. but few persons who have not been in new york since the construction of the elevated roads, and witnessed their equipments and operations, can have any adequate idea of the extent of them, and of the people, machinery, and appurtenances required in working them. a recent inventory discloses the fact that there are miles of roadway, stations, engines, and cars, while , trains a day are run. there are , men employed on these roads, of whom are engineers, ticket agents, conductors, firemen, guards or brakemen, gatemen, road inspectors, porters, carpenters, painters, car inspectors, car cleaners, lamp men, and blacksmiths, boiler makers, and other mechanics employed on the structure and in the shops. most of the ticket agents are telegraph operators, but there are other operators employed. there are four double-track lines in operation. the aggregate daily receipts vary from $ , to $ , ; and as many as , passengers have been carried in one day. engineers are paid from $ to $ . per day; ticket agents, $ . to $ . ; conductors, $ . to $ . ; firemen, $ . to $ ; guards or brakemen, $ . to $ . ; and gatemen, $ . to $ . . the above items do not include machinists and other _employés_ in the workshops, or the general officers, clerks, etc. * * * * * american antimony. a baltimore dispatch informs us that a carload of antimony, ten tons in all, was lately received by c.l. oudesluys & co., from the southern part of utah territory, being the first antimony received in the east from the mines of that section. the antimony was mined about miles from salt lake city. the ore is a sulphide, bluish gray in color, and yields from to per cent. of antimony. all antimony heretofore came from great britain and the island of borneo, and paid an import duty of per cent. ad valorem, and there is also some from sonora. it is believed that with proper rail facilities to the mines of the west there will be no need of importations. * * * * * some of the developments of mechanical engineering during the last half-century.[ ] [footnote : paper read in section g (mechanical) of the british association.] by sir frederick bramwell, v.p. inst. c.e., f.r.s., chairman of the council of the society of arts. i am quite sure the section will agree with me in thinking it was very fortunate for us, and for science generally, that our president refrained from occupying the time of the section by a retrospect, and devoted himself, in that lucid and clear address with which he favored us, to the consideration of certain scientific matters connected with engineering, and to the foreshadowing of the directions in which he believes it possible that further improvements may be sought for. but i think it is desirable that some one should give to this section a record, even although it must be but a brief and an imperfect one, of certain of the improvements that have been made, and of some of the progress that has taken place, during the last fifty years, in the practical application of mechanical science, with which science and its applications our section is particularly connected. i regret to say that, like most of the gentlemen who sat on this platform yesterday, who, i think, were, without exception, past presidents of the section, i am old enough to give this record from personal experience. fifty years ago i had not the honor of being a member, nor should i, it is true, have been eligible for membership of the association; but i was at that time vigorously making models of steam-engines, to the great annoyance of the household in which i lived, and was looking forward to the day when i should be old enough to be apprenticed to an engineer. without further preface, i will briefly allude to some of the principal developments of a few of the branches of engineering. i am well aware that many branches will be left unnoticed; but i trust that the omissions i may make will be remedied by those present who may speak upon the subject after me. i will begin by alluding to the steam-engine employed for manufacturing purposes. in , the steam-engine for these purposes was commonly the condensing beam engine, and was supplied with steam from boilers, known, from their shape, as wagon boilers; this shape appears to have been chosen rather for the convenience of the sweeps, who periodically went through the flues to remove the soot consequent on the imperfect combustion, than for the purpose of withstanding any internal pressure of steam. the necessary consequence was, that the manufacturing engines of those days were compelled to work with steam of from only ½ lb. to lb. per square inch of pressure above atmosphere. the piston speed rarely exceeded feet per minute, and as a result of the feeble pressure, and of the low rate of speed, very large cylinders indeed were needed relatively to the power obtained. the consumption of fuel was heavy, being commonly from lb. to lb. per gross indicated horsepower per hour. the governing of the engine was done by pendulum governors, revolving slowly, and not calculated to exert any greater effort than that of raising the balls at the end of the pendulum arms, thus being, as will be readily seen, very inefficient regulators. the connection of the parts of the engine between themselves was derived from the foundation upon which the engine was supported. incident to the low piston speed was slowness of revolution, rendering necessary heavy fly wheels, to obtain even an approach to practical uniformity of rotation, and frequently rendering necessary also heavy trains of toothed gearing, to bring up the speed from that of the revolutions of the engine to that of the machinery it was intended to drive. in , the boilers are almost invariably cylindrical, and are very commonly internally fired, either by one flue or by two; we owe it to the late sir william fairbairn, president of the british association in , that the danger, which at one time existed, of the collapse of these fire flues, has been entirely removed by his application of circumferential bands. nowadays there are, as we know, modifications of sir william fairbairn's bands, but by means of his bands, or by modifications thereof, all internally flued boilers are so strengthened that the risk of a collapse of the flue is at an end. boilers of this kind are well calculated to furnish--and commonly do furnish--steam of from lb. to lb. pressure above atmosphere. the piston speed is now very generally feet or more, so that, notwithstanding that there is usually a liberal expansion, the mean pressure upon the piston is increased, and this, coupled with its increased speed, enables much more power to be obtained from a given size of cylinder than was formerly obtainable. the revolutions of the engine now are as many as from to per minute, and thus, with far lighter fly-wheels, uniformity of rotation is much more nearly attained. the evaporative condenser. moreover, all the parts of the engine are self-contained; they no longer depend upon the foundation, and in many cases the condensing is effected either by surface condensers, or, where there is not sufficient water, the condensation is, in a few instances, effected by the evaporative condenser--a condenser which, i am sorry to say, is not generally known, and is therefore but seldom used, although its existence has been nearly as long as that of the association. notwithstanding the length of time during which the evaporative condenser has been known to some engineers, it is a common thing to hear persons say, when you ask them if they are using a condensing engine, "i can not use it; i have not water enough." a very sufficient answer indeed, if an injection condenser or an ordinary surface condenser constituted the sole means by which a vacuous condition might be obtained; but a very insufficient answer, having regard to the existence of the evaporative condenser, as by its means, whenever there is water enough for the feed of a non condensing engine, there is enough to condense, and to produce a good vacuum. the evaporative condenser simply consists of a series of pipes, in which is the steam to be condensed, and over which the water is allowed to fall in a continuous rain. by this arrangement there is evaporated from the outside of the condenser a weight of water which goes away in a cloud of vapor, and is nearly equal to that which is condensed, and is returned as feed into the boiler. the same water is pumped up and used outside the condenser, over and over, needing no more to supply the waste than would be needed as feed water. although this condenser has, as i have said, been in use for thirty or forty years, one still sees engines working without condensation at all, or with waterworks water, purchased at a great cost, and to the detriment of other consumers who want it for ordinary domestic purposes; or one sees large condensing ponds made, in which the injection water is stored to be used over and over again, and frequently (especially toward the end of the week) in so tepid a state as to be unfit for its purpose. the governing is now done by means of quick-running governors, which have power enough in them to raise not merely the weight of the pendulum ball, which is now small, but a very heavy weight, and in this way the governing is extremely effective. i propose to say no more, looking at the magnitude of the whole of my subject, upon the engine used for manufacturing purposes, but rather to turn at once to those employed for other objects. steam navigation. in , there were a considerable number of paddle steamers running along some of the rivers in england, and across the channel to the continent. but there were no ocean steamers, properly so-called, and there were no steamers used for warlike purposes. as in the case of the wagon boilers, the boilers of the paddle steamers of were most unsuited for resisting pressure. they were mere tanks, and there was as much pressure when there was no steam in the boiler from the weight of the water on the bottom, as there was at the top of the boiler from the steam pressure when the steam was up. under these circumstances, again, from ½ lb. to lb. was all the pressure the boilers were competent to bear, and as the engines ran at a slow speed, they developed but a small amount of horse-power in relation to their size. moreover, as in the land engine, the connection between the parts of the marine engine was such as to be incompetent to stand the strain that would come upon it if a higher pressure, with a considerable expansion, were used, and thus the consumption of coal was very heavy; and we know that, having regard to the then consumption, it was said, on high authority, it would be impossible for a steamboat to traverse the atlantic, as it could not carry fuel enough to take it across; and indeed it was not until that the sirius and the great western did make the passage. the passage had been made before, but it was not until that the passenger service can be said to have commenced. in , the marine boiler was supplied with salt water, the hulls were invariably of wood, and the speed was probably from eight to nine knots an hour. in , the vessels are as invariably either of iron or of steel, and i believe it will not be very long before the iron disappears, giving place entirely to the last mentioned metal. with respect to the term "steel," i am ready to agree that it is impossible to say where, chemically speaking, iron ends and steel begins. but (leaving out malleable cast iron) i apply this term "steel" to any malleable ductile metal of which iron forms the principal element and which has been in fusion, and i do so in contradistinction to the metal which may be similar chemically, but which has been prepared by the puddling process. applying the term steel in that sense, i believe, as i have said, it will not be very long before plate-iron produced by the puddling process will cease to be used for the purpose of building vessels. with respect to marine engines, they are now supplied with steam from multiple tubed boilers, the shells of which are commonly cylindrical. they are of enormous strength, and made with every possible care, and carry from lb. to lb. pressure on the square inch. it has been found, on the whole, more convenient to expand the steam in two or more cylinders, rather than in one. i quite agree that, as a mere matter of engineering science, there is no reason why the expansion should not take place in a single cylinder, unless it be that a single cylinder is cooled down to an extent which cannot be overcome by jacketing, and which, therefore, destroys a portion of the steam on its entering into the cylinder. as regards the propeller, as we know, except in certain cases, the paddle-wheel has practically disappeared, and the screw propeller is all but universally employed. the substitution of the screw propeller for the paddle enables the engine to work at a much higher number of revolutions per minute, and thus a very great piston speed, some ft. to ft. per minute, is attained; and this, coupled with the fairly high mean pressure which prevails, enables a large power to be got from a comparatively small-sized engine. speeds of knots an hour are now in many cases maintained, and on trial trips are not uncommonly exceeded. steam vessels are now the accepted vessels of war. we have them in an armored state and in an unarmored state, but when unarmored rendered so formidable, by the command which their speed gives them of choosing their distance, as to make them, when furnished with powerful guns, dangerous opponents even to the best armored vessels. marine governors. we have also now marine engines, governed by governors of such extreme sensitiveness as to give them the semblance of being endowed with the spirit of prophecy, as they appear rather to be regulating the engine for that which is about to take place than for that which is taking place. this may sound a somewhat extravagant statement, but it is so nearly the truth, that i have hardly gone outside of it in using the words i have employed. for a marine governor to be of any use, it must not wait till the stern of the vessel is out of the water before it acts to check the engine and reduce the speed. nothing but the most sensitive, and, indeed, anticipatory action of the governors can efficiently control marine propulsion. instances are on record of vessels having engines without marine governors being detained by stress of weather at the mouth of the thames, while vessels having such governors, of good design, have gone to newcastle, have come back, and have found the other vessels still waiting for more favorable weather. with respect to condensation in marine engines, it is almost invariably effected by surface condensers, and thus it is that the boilers, instead of being fed with salt water as they used to be, involving continuous blowing off, and frequently the salting up, of the boiler, are now fed with distilled water. it should be noticed, however, that in some instances, owing to the absence of a thin protecting scale upon the tubes and plates, very considerable corrosion has taken place when distilled water, derived from condensers having untinned brass tubes, has been used, and where the water has carried into the boiler fatty acids, arising from the decomposition of the grease used in the engine; but means are now employed by which these effects are counteracted. light engines and boilers. i wish, before quitting this section of my subject, to call your attention to two very interesting but very different kinds of marine engines. one is the high-speed torpedo vessel, or steam launch, of which messrs. thornycroft's firm have furnished so many examples. in these, owing to the rate at which the piston runs to the initial pressure of lb. and to very great skill in the design, messrs. thornycroft have succeeded in obtaining a gross indicated horse-power for as small a weight as half a cwt., including the boiler, the water in the boiler, the engine, the propeller shaft, and the propeller itself. to obtain the needed steam from the small and light boiler, recourse has to be made to the aid of a fan blast driven into the stoke-hole. from the use of a blast in this way advantages accrue. one is, as already stated, that from a small boiler a large amount of steam is produced. another is that the stoke-hole is kept cool; and the third is that artificial blasts thus applied are unaccompanied by the dangers which arise, when under ordinary circumstances the blast is supplied only to the ash-pit itself. the perkins system. the second marine engine to which i wish to call your attention is one that has been made with a view to great economy. the principles followed in its construction are among those suggested by the president (sir w.g. armstrong) in his address. he (you will remember) pointed out that the direction in which economy in the steam engine was to be looked for was that of increasing the initial pressure; although at the same time he said that there were drawbacks in the shape of greater loss, by radiation, and by the higher temperature at which the products of combustion will escape. we must admit the fact of the latter source of loss, when using very high steam, it being inevitable that temperature of the products of combustion escaping from a boiler under these conditions must be higher than those which need be allowed to escape when lower steam is employed; although i regret to say that in practice in marine boilers working at comparatively low pressures the products are ordinarily suffered to pass into the funnel at above the temperature of melted lead. but with respect to the loss by radiation in the particular engine i am about to mention--that of perkins--there is not as much loss as that which prevails in the ordinary marine boilers, because the perkins boiler is completely inclosed, with the result that while there is within the case a boiler containing steam of lb. on the square inch, and the fire to generate that steam, the hand may be applied to the casting itself, which contains the whole of the boiler, without receiving any unpleasant sensation of warmth. by mr. perkins's arrangement, using steam of lb. in the boiler, it was found, as the result of very severe trials, conducted by mr. rich, of messrs. easton and anderson's firm, and myself--trials which lasted for twelve hours--that the total consumption of fuel, including that for getting up steam from cold water, was just under . , actually . lb. per gross indicated horse-power per hour. that gross indicated horse-power was obtained in a manner which it is desirable should always be employed in steamboat trials. it was not got by using as a divisor the horse-power of the most favorable diagram obtained during the day; but it was got from diagrams taken during the regular work; then, every half-hour, when the pressure began to die down, from coal being no longer put upon the fire, diagrams taken every quarter of an hour, and then toward the last, every five minutes; and the total number of foot pounds were calculated from these diagrams, and were used to obtain the gross indicated horse-power. further, so far as could be ascertained by the process of commencing a trial with a known fire, and closing that trial at the end of six hours, with the fire as nearly as possible in the same condition, the consumption was . lb. of coal per gross indicated horse-power per hour. so that, without taking into account the coal consumed in raising steam from cold water, the engine worked for - / lb. of coal per horse per hour. i think it well to give these details, because undoubtedly it is an extremely economical result. ether engine. our president alluded to the employment of ether as a means of utilizing the heat which escaped into the condenser, and gave some account of what was done by mons. du tremblay in this direction. it so happened that i had occasion to investigate the matter at the time of du tremblay's experiments; very little was effected here in england, one difficulty being the excise interference with the manufacture of ether. chloroform was used here, and it was also suggested to employ bisulphide of carbon. in france, however, a great deal was done. four large vessels were fitted with the ether engines, and i went over to marseilles to see them at work. i took diagrams from these engines, and there is no doubt that, by this system, the exhaust steam from the steam cylinder, which was condensed by the application of ether to the surface of the steam condenser (producing a respectable vacuum of about inches), gave an ether pressure of lb. on the square inch above atmosphere, and very economical results as regards fuel were obtained. the scheme was, however, abandoned from practical difficulties. it need hardly be said that ether vapor is very difficult to deal with, and although ether is light, the vapor is extremely heavy, and if there is any leakage, it goes down into the bilges by gravitation, and being mixed with air, unless due care is taken to prevent access to the flues, there would be a constant risk of a violent explosion. in fact, it was necessary to treat the engine room in the way in which a fiery colliery would be treated. the lighting, for instance, was by lamps external to the engine room, and shining through thick plate-glass. the hand lamps were davy's. the ether engine was a bold experiment in applied science, and one that entitles du tremblay's name to be preserved, and to be mentioned as it was by our president. the quicksilver engine. these was another kind of marine engine that i think should not be passed over without notice; i allude to howard's quicksilver engine. the experiments with this engine were persevered in for some considerable time, and it was actually used for practical purposes in propelling a passenger steam-vessel called the vesta, and running between london and ramsgate. in that engine the boiler had a double bottom, containing an amalgam of quicksilver and lead. this amalgam served as a reservoir of heat, which it took up from the fire below the double-bottom, and gave forth at intervals to the water above it. there was no water in the boiler, in the ordinary sense of the term, but when steam was wanted to start the engine, a small quantity of water was injected by means of a hand-pump, and after the engine was started, there was pumped by it into the boiler, at each half revolution, as much water as would make the steam needed. this water was flashed on the top surface of the reservoir in which the amalgam was confined, and was entirely turned into steam, the object of the engineers in charge being to send in so much water as would just generate the steam, but so as not to leave any water in the boiler. the engines of the vesta were made by mr. penn, for mr. howard, of the king and queen ironworks, rotherhithe. mr. howard was, i fear, a considerable loser by his meritorious efforts to improve the steam-engine. there was used, with this engine, an almost unknown mode of obtaining fresh water for the boiler. fresh water, it will be seen was a necessity in this mode of evaporation. the presence of salt, or of any other impurity, when the whole of the water was flashed into steam, must have caused a deposit on the top of the amalgam chamber at each operation. fresh water, therefore, was needed; the problem arose how to get it; and that problem was solved, not by the use of surface condensation, but by the employment of reinjection, that is to say, the water delivered from the hot well was passed into pipes external to the vessel; after traversing them, it came back into the injection tank sufficiently cooled to be used again. the boilers were worked by coke fires, urged by a fan blast in their ashpits, but i am not aware that this mode of firing was a needful part of the system. locomotive engines. i come now to the engines used for railways. at the british association meeting of , the manchester and liverpool railway had been opened only about a year. the stockton and darlington coal line, it is true, had carried passengers by steam power as early as , but i think we may look upon the manchester and liverpool as being the beginning of the passenger and mercantile railway system of the present day. at that time the locomotives weighed from eight to ten tons, and the speed was about miles per hour, with a pressure of from to lb. the rails were light; they were jointed in the chairs, which were generally carried on stone blocks, thus affording most excellent anvils for the battering to pieces of the ends of the rails--that is to say, for the destruction of the very parts where they were most vulnerable. the engines were not competent to draw heavy trains, and it was a common practice to have at the foot of an incline a shed containing a "bank engine," which ran out after the trains as they passed, and pushed them up to the top of the hill. injectors were then unknown, and donkey-pumps were unknown, and therefore, when it was necessary to fill up the boiler, if it had not been properly pumped up before the locomotive came to rest, it had to run about the line in order to work its feed-pumps. to get over this difficulty, it was occasionally the practice to insert into a line of rails, in a siding, a pair of wheels, with their tops level with that of the rails so that the engine wheels could run upon the rims. then, the locomotive being fixed to prevent it from moving off the pair of wheels thus endways, it was put into revolution, its driving wheels bearing, as already stated, upon the rims of the pair of wheels in the rails, and thus the engine worked its feed-pumps without interfering (by its needless running up and down the line) with the traffic. it should have been stated, that at this time there was no link motion, no practical expansion of the steam, and that even the reversal of the engine had to be effected by working the sides by hand gear, in the manner in use in marine engines. when the british association originated, although the manchester and liverpool railway had been opened for a year, there is no doubt that the members who then came to this city found their way here by the slow process of the stage-coach, the loss of which we so much deplore in the summer and in fine weather, but the obligatory use of which we should so much regret in the miserable weather now prevailing in these islands. in , we know that railways are everywhere inserted. steel rails, double the weight of the original iron ones, are used. wooden sleepers have replaced the stone blocks, and they, in their turn, will probably give way to sleepers of steel. the joints are now made by means of fish-plates, and the most vulnerable part of the rail, the end, is no longer laid on an anvil for a purpose of being smashed to pieces, but the ends of the rails are now almost always over a void, and thereby are not more affected by wear than is any other part of the rail. the speed is now from to miles an hour for passenger trains, while slow speed goods engines, weighing tons, draw behind them coal trains of tons. the injector is now commonly employed, and, by its aid, a careful driver of the engine of a stopping train can fill up his boiler while at rest at the stations. the link motion is in common use, to which, no doubt, is owing the very considerable economy with which the locomotive engine now works. as regards the question of safety, it is a fact that, notwithstanding the increased speed, railway accidents are fewer than they were at the slow speed. it is also a fact, that if the whole population of london were to take a railway journey, there would be but one death arising out of it. four millions of journeys for one death of a passenger from causes beyond his own control is, i believe, a state of security which rarely prevails elsewhere. as an instance, the street accidents in london alone cause between and deaths per annum. this safety in railway traveling is no doubt largely due to the block system, rendered possible by the electric telegraph; and also to the efficient interlocking of points and signals, which render it impossible now for a signal man to give an unsafe signal. he may give a wrong one, in the sense of inviting the wrong train to come in; but, although wrong in this sense, it would still be safe for that train to do so. if he can give a signal, that signal never invites to danger; before he can give it, every one of the signals, which ought to be "at danger," must be "at danger," and every "point" must have been previously set, so as to make the road right; then, again, we have the facing point-lock, which is a great source of safety. brakes. further, we have continuous brakes of various kinds, competent in practice to absorb three miles of speed in every second of time; that is to say, if a train were going miles an hour, it can be pulled up in seconds; or, if at the rate of miles, in seconds. with a train running at miles an hour, it can be pulled up in from to seconds, and in a distance of from to yards. moreover, in the event of the train separating into two or more sections, the brakes are automatically applied to each section, thereby bringing them to rest in a short time. another cause of safety is undoubtedly the use of weldless tires. i was fortunate enough to attend the british association meeting many years ago at birmingham, and i then read a paper upon weldless tires, in which i ventured to prophesy that, in ten years' time, there would not be a welded tire made; that is one of the few prophecies that, being made before the event, have been fulfilled. i may perhaps be permitted to mention, that at the same time i laid before the section plans and suggestions for the making of the cylindrical parts of boilers equally without seam, or even welding. this is rarely done at the present time, but i am sure that, in twenty years' time, such a thing as a longitudinal seam of rivets in a boiler will be unknown. there is no reason why the successive rings of boiler shells should not be made weldless, as tires are now made weldless. motors. the next subject i intend to deal with is that of motors. in , we had the steam-engine, the water-wheel, the windmill, horse-power, manual power, and stirling's hot air engines. gas engines, indeed, were proposed in , but were not brought to the really practical stage. we had then tide mills; indeed, we have had them until quite lately, and it may be that some still exist; they were sources of economy in our fuel, and their abandonment is to me a matter of regret. i remember tide mills on the coast between brighton and newhaven, another between greenwich and woolwich, another at northfleet, and in many other places. indeed, such mills were used pretty extensively; they were generally erected at the mouth of a stream, and in that way the river bed made the reservoir, and even when they were erected in other situations, those were of a kind suitable for the purpose, that is, lowlying lands were selected, and were embanked to form reservoirs. in , windmills and water-wheels are much the same, but the turbines are greatly improved, and by means of turbines we are enabled to make available the pressure derived from heads of water which formerly could not be used at all, or if used, involved the erection of enormous water-wheels, such as those at glasgow and in the isle of man, wheels of some eighty feet in diameter. but now, by means of a small turbine, an excellent effect is produced from high heads of water. the same effect is obtained from the water-engines which our president has employed with such great success. in addition to these motors, we have the gas-engine, which, within the last few years only, has become a really useful working and economical machine. with respect to horse-power motors, we have not only the old horse engines, but we have a new application, as it seems to me, of the work of the horse as a motor. i allude to those cases where the horse drawing a reaping or thrashing machine, not only pulls it forward as he might pull a cart, but causes its machinery to revolve, so as to perform the desired kind of work. this species of horse-engine, though known, was but little used in . with respect to hot-air engines there have been many attempts to improve them, and some hot-air engines are working, and are working with considerable success; but the amount of power they develop in relation to their size is small, and i am inclined to doubt whether it can be much increased. transmission of power. i now come to the subject of the transmission of power. i do not mean transmission in the ordinary sense by means of shafting, gearing, or belting, but i mean transmission over long distances. in , we had for this purpose flat rods, as they were called, rods transmitting power from pumping engines for a considerable distance to the pits where the pumps were placed, and we had also the pneumatic, the exhaustion system--the invention of john hague, a yorkshire-man, my old master, to whom i was apprenticed--which mode of transmission was then used to a very considerable extent. the recollection of it, i find, however, has nearly died out, and i am glad to have this opportunity of reviving it. but in , we have, for the transmission of power, first of all, quick moving ropes, and there is not, so far as i know a better instance of this system than that at schaffhausen. any one who has ever, in recent years, gone a mile or two above the falls at schaffhausen, must have seen there--in a house, on the bank of the rhine, opposite to that on which the town is situated--large turbines driven by the river, which is slightly dammed up for the purpose. these work quick-going ropes, carried on pulleys, erected at intervals along the river bank, for the whole length of the town; and power is delivered from them to shafting below the streets, and from it into any house where it is required for manufacturing purposes. then we have the compressed air transmission of power, which is very largely used for underground engines, and for the working of rock drills in mines and tunnels. compressed air locomotives. we have also compressed air in a portable form, and it is now employed with great success in driving tram-cars. i had occasion last january to visit nantes, where, for eighteen months, tram-cars had been driven by compressed air, carried on the cars themselves, coupled with an extremely ingenious arrangement for overcoming the difficulties commonly attendant on the use of compressed air engines. this consists in the provision of a cylindrical vessel half filled with hot water and half with steam, at a pressure of eighty pounds on the square inch. the compressed air, on its way from the reservoir to the engine, passes through the water and steam, becoming thereby heated and moistened, and in that way all the danger of forming ice in the cylinders was prevented, and the parts were susceptible of good lubrication. these cars, which start every ten minutes from each end, make a journey of ¾ miles, and have proved to be a commercial and an engineering success. i believe, moreover, that they are capable of very considerable improvement. hydraulic transmission of power. then there is, although not much used, the transmitting of power by means of long steam pipes. there is also the transmission hydraulically. this may be carried out in an intermittent manner, so as to replace the reciprocating flat rods of old days; that is to say, if two pipes containing water are laid down, and if the pressure in those pipes at the one end be alternated, there will be produced an alternating and a reciprocative effect at the other, to give motion to pumps or other machinery. there is also that thoroughly well known mode of transmission, hydraulically, for which the engineering world owes so much to our president. we have, by sir william armstrong's system, coupled with his accumulator, the means of transmitting hydraulically the power of a central motor to any place requiring it, and by the means of the principal accumulator, or if need be by that aided by local accumulators, a comparatively small engine is enabled to meet very heavy demands made upon it for a short time. i think i am right in saying that, at the ordinary pressure which sir william armstrong uses in practice, viz., lb. to the square inch, one foot a second of motion along an inch pipe would deliver at the rate to produce one-horse power. therefore, a ten-inch pipe, with the water traveling at no greater pace than three feet in a second, would deliver horse-power. this horse-power would no doubt be somewhat reduced by the loss in the hydraulic engine, which would utilize the water. but the total energy received would be equivalent to producing horse-power. such a transmission would be effected with an exceedingly small loss infliction in transit. i believe i am right in saying that a inch pipe a mile long would not involve much more than about or lb. differential pressure to propel the water through it at the rate of three feet in a second. if that be so, then, with lb. to the inch, the loss under such circumstances would be only two per cent. in transmission. there is no doubt that this transmission of power hydraulically has been of the greatest possible use. it has enabled work to be done which could not be done before. enormous weights are raised with facility wherever required, as by the aid of power hydraulically transmitted, it is perfectly easy for one man to manage the heaviest cranes. moreover, as i have said in other places, the system which we owe to sir william armstrong has gone far to elevate the human race, and it has done so in this manner. so long as it is competent for a man to earn a living by mere unintelligent exercise of his muscles, he is very likely to do it. you may see in the old london docks the crane-heads covered by structures that look like paddle-boxes. if you go to them, there is, i am glad to say, nothing now to fill them up; but when the british association first met, these paddle-boxes covered large tread-wheels, in which men trod, so as to raise a weight. now, although i know that in fact there is nothing more objectionable in a man turning a wheel by treading inside of it than there is if he turn it round by a winch-handle, yet somehow it strikes one more as being merely the work of an animal, a turnspit, or a squirrel, or, indeed, as the task imposed on the criminal. but, nevertheless, in this way there were a large number of persons getting their living by the mere exercise of their muscles, but, as might be expected, a very poor living, derived as it was from unintelligent labor. that work is no longer possible, and is not so, for the powerful reason that it does not pay. those persons, therefore, who would now have been thus occupied, are compelled to elevate themselves, and to become competent to earn their living in a manner which is more worthy of an intelligent human being. it is on these grounds that i say we owe very much the elevation of the working classes, especially of the class below the artisan, to this invention of our distinguished president. electric transmission of power. in addition to the modes of transmission i have already mentioned, there is the transmission of power by means of gas. i think that there is a very large future indeed for gas engines. i do not know whether this may be the place to state it, but i believe the way in which we shall utilize our fuel hereafter will, in all probability, not be by the way of the steam-engine. sir william armstrong alluded to this probability in his address, and i entirely agree, if he will allow me to say so, that such a change in the production of power from fuel appears to be impending, if not in the immediate future, at all events in a time not very far remote; and however much the mechanical section of the british association may to-day contemplate with regret, even the mere distant prospect of the steam-engine being a thing of the past, i very much doubt whether those who meet here fifty years hence will then speak of it as anything more than a curiosity to be found in a museum. with respect to the transmission of power electrically, i won't venture to touch upon that; but will content myself by reminding you that while sir william armstrong did say that there were comparatively small streams which could be utilized, he did not inform you of that which he himself had done in this direction; let me say that sir william armstrong thus utilized a fall of water, situated about a mile from his house, to work a turbine, which drives a dynamo machine, generating electricity, for the illumination of the house. when i was last at crag side, that illumination was being effected by the arc light, but since then, as sir william armstrong has been good enough to write to me, he has replaced the arc light by the incandescent lamp (a form of electrical lighting far more applicable than the arc light to domestic purposes), and with the greatest possible success. thus, in sir william armstrong's own case, a small stream is made to afford light in a dwelling a mile away. certainly nothing could have seemed more improbable fifty years ago than that the light of a house should be derived from a fall of water without the employment of any kind or description of fuel. the next subject upon which i propose to touch is that of the manufacture of iron and steel. in , neilson's hot blast specification had been published for two and a half years only. the butterly company had tried the hot blast for the first time in the november preceding the meeting of the british association. the heating of the blast was coming very slowly into use, and the temperature attained when it was employed was only some degrees. the ordinary blast furnace of those days was to feet high, and about feet diameter at the boshes, and turned out about tons a week. it used about ½ tons of coal per ton of iron, and no attempt was made to utilize the waste gases, whether escaping in the form of gas or in the form of flame, the country being illuminated for miles around at night by these fires. the furnaces were also open at the hearth, and continuous fire poured out along with the slag. in , blast furnaces are from ft. to ft. high, and ft. in diameter at the boshes; they turn out from to tons a week. the tops and also the hearths are closed, and the blast--thanks to the use of mr. e.a. cowper's stoves--is at , degrees. the manufacture of iron has also now enlisted in its service the chemist as well as the engineer, and among those who have done much for the improvement of the blast furnaces, to no one is greater praise due than to mr. isaac lowthian bell, who has brought the manufacture of iron to the position of a highly scientific operation. in the production of wrought iron by the puddling process, and in the subsequent mill operations, there is no very considerable change, except in the magnitude of the machines employed, and, in the greater rapidity with which they now run. in saying this, i am not forgetting the various "mechanical puddlers" which have been put to work, nor the attempts that have been made by the use of some of them to make wrought iron direct from the ore; but neither the "mechanical puddler" nor the "direct process" has yet come into general use; and i desire to be taken as speaking of that which is the ordinary process pursued at the present in puddled iron manufactures. in , a few hundredweights was the limit of weight of a plate, while in , there may readily be obtained, for boiler-making purposes, plates of at least four times the weight of those that were made in . i may, perhaps, be allowed to say that there is an extremely interesting blue-book of the year , containing the report of a parliamentary committee which sat on boiler explosions, and i recommend any mechanical engineer who is interested in the history of the subject to read that book; he will find it there stated that in the north of england there was a species of engines called locomotives, the boilers of which were made of wrought iron, beaten, not rolled, because the rolled plate was not considered fit; it was added that if made of beaten iron the boiler would last at least a year. in , thirteen years later, the dimensions of rolled plates were no doubt raised; but few then would have supposed it possible there should be rolled such plates as are now produced for boiler purposes, and still fewer would have believed that in the year we should make, for warlike purposes, rolled plates inches in thickness and tons in weight. i have said there is very little alteration in the process of making wrought iron by puddling, and i do not think there is likely to be much further, if any, improvement in this process, because i believe that, with certain exceptions, the manufacture of iron by puddling is a doomed industry. i ventured to say, in a lecture i delivered at the royal institution three years ago on "the future of steel," that i believed puddled iron, except for the mere hand wrought forge purposes of the country blacksmith, and for such like purposes, would soon become a thing of the past. mr. harrison, the engineer of the north-eastern railway, told me that about eighteen months ago the north-eastern railway applied for tenders for rails in any quantities between , and , tons, and they issued alternative specifications for iron and for steel. they received about ten tenders. some did not care to tender for iron at all; but when they did tender alternatively, the price quoted for the iron was greater than for the steel. i have no doubt whatever that, in a short time, it will be practically impossible to procure iron made by the puddling process, of dimensions fit for many of the purposes for which a few years ago it alone was used. with respect to steel, in the process in use was that of cementation, producing blistered steel, which was either piled and welded to make shear steel, or was broken into small pieces, melted in pots, and run into an ingot weighing only some lb. or lb. at that time steel was dealt in by the pound; nobody thought of steel in tons. in , we are all aware that, by sir henry bessemer's well-known discovery, carried out by him with such persistent vigor, cast iron is, by the blowing process, converted into steel, and that of dr. siemens' equally well-known process (now that, owing to his invention of the regenerative furnace, it is possible to obtain the necessary high temperature), steel is made upon the open hearth. we are, moreover, aware that, by both of these processes, steel is produced in quantities of many tons at a single operation, with the result that as instanced in the case of the north-eastern rails, steel is a cheaper material than the wrought iron made by the puddling process. one cannot pass away from the steel manufacture without alluding to sir joseph whitworth's process of putting a pressure on the steel while in a tried state. by this means, the cavities which are frequently to be found in the ingot of a large size are, while the steel is fluid, rendered considerably smaller, and the steel is thereby rendered much more sound. in conclusion of my observations on the subject of iron and steel manufacture, i wish to call attention to the invention of messrs. thomas & gilchrist, by which ores of iron, containing impurities that unfitted them to be used in the manufacture of steel, are now freed from these impurities, and are thus brought into use for steel-making purposes. bridges. in the year , bridges of cast iron existed; but no attempt had been made to employ wrought iron in girder bridges, although telford had employed it in the menai suspension bridge; but in , the introduction of railways, and the improvement in iron manufactures, have demanded, and have rendered possible the execution of such bridges as the tubular one, spanning the menai straits, in span of feet, and the saltash, over the tamar, with spans of feet; while recent great improvements in the manufacture of steel have rendered possible the contemplated construction of the forth bridge, where there are to be spans of , feet, or one-third of a mile in length. mr. barlow, one of the engineers of this bridge, has told me that there will be used upwards of , more tons of material in the forth bridge, to resist the wind pressure, than would have been needed if no wind had to be taken into account, and if the question of the simple weight to be carried had alone to be considered. with respect to the foundation of bridges, that ingenious man, lord cochrane, patented a mode of sinking foundations, even before the first meeting of the british association, viz., as far back, i believe, as or ; and the improvements which he then invented are almost universally in use in bridge construction at the present day. cylinders sunk by the aid of compressed air, airlocks to obtain access to the cylinder, and, in fact, every means that i know of as having been used in the modern sinking of cylinder foundations, were described by lord cochrane (afterwards earl of dundonald) in that specification. the next subject i propose to touch on is that of machine tools. in , the mention of lathes, drilling machines, and screwing machines brings me very nearly to the end of the list of the machine tools used by turners and fitters, and at that time many lathes were without slide rests. the boiler-maker had then his punching-press and shearing machine; the smith, leaving on one side his forges and their bellows, had nothing but hand tools, and the limit of these was a huge hammer, with two handles, requiring two men to work it. in anchor manufacture, it is true, a mechanical drop-hammer, known as a hercules, was employed, while in iron works, the helve and the tilt hammer were in use. for ordinary smith's work, however, there were, as has been said, practically no machine tools at all. this paucity or absence in some trades, as we have seen, of machine tools, involved the need of very considerable skill on the part of the workman. it required the smith to be a man not only of great muscular power, but to be possessed of an accurate eye and a correct judgment, in order to produce the forgings which were demanded of him, and to make the sound work that was needed, especially when that soundness was required in shafts, and in other pieces which, in those days, were looked upon as of magnitude; which, indeed, they were, relatively to the tools which could be brought to operate upon them. the boiler-maker in his work had to trust almost entirely to the eye for correctness of form and for regularity of punching, while all parts of engines and machines which could not be dealt with in the lathe, in the drilling, or in the screwing machine, had to be prepared by the use of the chisel and the file. at the present day, the turning and fitting shops are furnished not only with the slide lathe, self acting in both directions, and screw-cutting, the drilling-machine, and the screwing machine, but with planing machines competent to plane horizontally, vertically, or at an angle; shaping machines, rapidly reciprocating, and dealing with almost any form of work; nut shaping machines, slot drilling machines, and slotting machines, while the drills have become multiple and radial; and the accuracy of the work is insured by testing on large surface plates, and by the employment of whitworth internal and external standard gauges. the boiler maker's tools now comprise the steam, compressed air, hydraulic or other mechanical riveter, rolls for the bending of plates while cold into the needed cylindrical or conical forms, multiple drills for the drilling of rivet holes, planing machines to plane the edges of the plates, ingenious apparatus for flanging them, thereby dispensing with one row of rivets out of two, and roller expanders for expanding the tubes in locomotive and in marine boilers; while the punching press, where still used, is improved so as to make the holes for seams of rivets in a perfect line, and with absolute accuracy of pitch. with respect to the smith's shop, all large pieces of work are now manipulated under heavy nasmyth or other steam hammers; while smaller pieces of work are commonly prepared either in forging machines or under rapidly moving hammers, and when needed in sufficient numbers are made in dies. and applicable to all the three industries of the fitting shop, the boiler shop, and the smith's shop, and also to that other industry carried on in the foundry, are the traveling and swing cranes, commonly worked by shafting, or by quick moving ropes for the travelers, and by hydraulic power or by steam engines for the swing cranes. it may safely be said, that without the aid of these implements, it would be impossible to handle the weights that are met with in machinery of the present day. i now come to one class of machine which, humble and small as it is, has probably had a greater effect upon industry and upon domestic life than almost any other. i mean the sewing machine. in , there was no means of making a seam except by the laborious process of the hand needle. in , eldred walker patented a machine for parsing the basting thread through the gores of umbrellas, a machine that was very ingenious and very simple, but was utterly unlike the present sewing machine, with its eye-pointed needle, using sometimes two threads (the second being put in by a shuttle or by another needle), and making stitches at twenty-fold the rapidity with which the most expert needlewoman could work. by means of the sewing machine not only are all textile fabrics operated upon, but even the thickest leather is dealt with, and as a _tour de force_, but as a matter of fact, sheet-iron plates themselves have been pierced, and have been united by a seam no boilermaker ever contemplated, the piercing and the seam being produced by a blake sewing machine. i believe all in this section will agree that the use of the sewing machine has been unattended by loss to those who earn their living by the needle; in fact, it would not be too much to say that there has been a positive improvement in their wages. the next matter i have to touch upon is agricultural machinery. in , we had thrashing machines and double plows, and even multiple plows had been proposed, tried, and abandoned. reaping machines had been experimented with and abandoned; sowing machines were in use, but not many of them; clod crushers and horse rakes were also in use; but as a fact plowing was done by horse power with a single furrow at a time, mowing and reaping were done by the scythe or the sickle, sheaves were bound by hand, hay was tedded by hand-rakes, while all materials and produce were moved about in carts and in wagons drawn by horses. at the present time we have multiple plows, making five or six furrows at a time, these and cultivators also, driven by steam, commonly from two engines on the head lands, the plow being in between, and worked by a rope from each engine, or if by one engine, a capstan on the other head land, with a return rope working the plow backward and forward; or by what is known as the roundabout system, where the engine is fixed and the rope carried round about the field; or else plows and cultivators are worked by ropes from two capstans placed on the two head lands, and driven by means of a quick-going rope, actuated by an engine, the position of which is not changed. and then we have reaping machines, driven at present by horses; but how long it will be before the energy residing in a battery, or that in a reservoir of compressed air, will supersede horse power to drive the reaping machine, i don't know, but i don't suppose it will be very long. the mowing and reaping machines not only cut the crop and distribute it in swaths, or, in the case of the reaping machine, in bundles, but now, in the instance of these latter machines, are competent to bind it into sheaves. in lieu of hand tedding, haymaking machines are employed, tossing the grass into the air, so as to thoroughly aerate it, taking advantage of every brief interval of fine weather; and seed and manure are distributed by machine with unfailing accuracy. the soil is drained by the aid of properly constructed plows for preparing the trenches; roots are steamed and sliced as food for cattle; and the thrashing machine no longer merely beats out the grain, but it screens it, separates it, and elevates the straw, so as to mechanically build it up into a stack. i do not know a better class of machine than the agricultural portable engine. every part of it is perfectly proportioned and made; it is usually of the locomotive type, and the economy of fuel in its use is extremely great. i cannot help thinking that the improvement in this respect which has taken place in these engines, and the improvement of agricultural machinery generally, is very largely due to the royal agricultural society, one of the most enterprising bodies in england. i now come to the very last subject i propose to speak upon, and that is printing machinery, and especially as applied to the printing of newspapers. in , we had the steam press sending out a few hundred copies in an hour, and doing that upon detached sheets, and thus many hours were required for an edition of some thousands. the only way of expediting the matter would have been to have recomposed the paper, involving, however, double labor to the compositors, and a double chance of error. at the present day, we have, by the walter press, the paper printed on a continuous sheet at a rate per hour at least three times as great as that of the presses of , and, by the aid of _papier máché_ moulds, within five minutes from the starting of the first press, a second press can be got to work from the stereotype plates, and a third one in the next five minutes; and thus the wisdom of our senators, which has been delivered as late as three o'clock in the morning, is able to be transmitted by the newspaper train leaving euston at : a.m. this is the last matter with which i shall trouble the section. i have purposely omitted telegraphy; i have purposely omitted artillery, textile fabrics, and the milling and preparation of grain. these and other matters i have omitted for several reasons. some i have omitted because i was incompetent to speak upon them, others because of the want of time, and others because they more properly belong to section a. i hope, sir, although your address, dealing with the future, was undoubtedly the right address for a president to deliver, and although it is equally right that we should not content ourselves with merely looking back in a "rest and be thankful" spirit at the various progress which this paper records, it may nevertheless be thought well that there should have been brought before the section, in however cursory a manner, some notice of mechanical development during the past fifty years. * * * * * [continued from supplement, no. , page .] amateur mechanics. metal turning. in selecting a lathe an amateur may exercise more or less taste, and he may be governed somewhat by the length of his purse; the same is true in the matter of chucks; but when he comes to the selection or making of turning tools he must conform to fundamental principles; he must profit as far as possible by the experience of others, and will, after all, find enough to be learned by practice. tools of almost every description may be purchased at reasonable prices, but the practice of making one's own tools cannot be too strongly recommended. it affords a way out of many an emergency, and where time is not too valuable, a saving will be realized. a few bars of fine tool steel, a hammer, and a small anvil, are all that are required, aside from fire and water. the steel should be heated to a low red, and shaped with as little hammering as possible; it may then be allowed to cool slowly, when it may be filed or ground to give it the required form. it may now be hardened by heating it to a cherry red and plunging it straight down into clean cool (not too cold) water. it should then be polished on two of its sides, when the temper may be drawn in the flame of an alcohol lamp or bunsen gas burner; or, if these are not convenient, a heated bar of iron may be used instead, the tool being placed in contact with it until the required color appears. this for tools to be used in turning steel, iron, and brass may be a straw color. for turning wood it may be softer. the main point to be observed in tempering a tool is to have it as hard as possible without danger of its being broken while in use. by a little experiment the amateur will be able to suit the temper of his tools to the work in hand. in the engraving accompanying the present article a number of hand turning tools are shown, also a few tools for the slide rest. these tools are familiar to machinists and may be well known to many amateurs; but we give them for the benefit of those who are unacquainted with them and for the sake of completeness in this series of articles. [illustration: turning tools.] fig. is the ordinary diamond tool, made from a square bar of steel ground diagonally so as to give it two similar cutting edges. this tool is perhaps more generally useful than any of the others. the manner of using it is shown in fig. ; it is placed on the tool rest and dexterously moved on the rest as a pivot, causing the point to travel in a circular path along the metal in the lathe. of course only a small distance is traveled over before the tool is moved along on the rest. after a little experience it will be found that by exercising care a good job in plain turning may be done with the tool. fig. shows a sharp v shaped tool which will be found useful for many purposes. fig. is a v shaped tool for finishing screw threads. figs. and are round-nosed tools for concave surfaces; fig. , a square tool for turning convex and plane surfaces. the tool shown in fig. should be made right and left; it is useful in turning brass, ivory, hard wood, etc. fig. is a separating tool; fig. is an inside tool, which should be made both right and left, and its point may be either round, v shaped, or square. fig. shows the manner of holding an inside tool. fig. is a tool for making curved undercuts. fig. is a representative of a large class of tools for duplicating a given form. these figures represent a series of tools which may be varied infinitely to adapt them to different purposes. the user, if he is wide awake, is not long in discovering what angle to give the cutting edge, what shape to give the point, and what position to give the tool in relation to the work to be done. having had experience with hand tools it requires only a little practice and observation to apply the same principles to slide rest tools. a few examples of this class of tools are given. fig. is the ordinary diamond pointed tool, which should be made right and left. the cutting edge may have a more or less acute angle, according to the work to be done, and the inclined or front end of the tool may be slightly squared or rounded, according to the work. fig. is a separating tool, which is a little wider at the cutting edge than any where else, so that it will clear itself as it is forced into the work. for brass this tool should be beveled downward slightly. by giving the point the form shown in fig. it will be adapted to screw cutting. fig. shows an inside tool for the slide rest; its point may be modified according to the work to be done. fig. is a side tool for squaring the ends of shafts; figs. , , , and represent tools for brass, fig. is a round-nosed tool for brass, fig. a v shaped tool, fig. a screw thread tool, and fig. a side tool. in boring, whether the object is cored or not, it is desirable, where the hole is not too large, to take out the first cut with a drill. the drill for the purpose is shown in fig. , the drill holder in fig. , and the manner of using in fig . the drill holder, b, is held by a mortised post placed in the rest support. the slot of the drill holder is placed exactly opposite the tail center and made secure. the drill, which is flat, is drilled to receive the tail center, and it is kept from turning by the holder, and is kept from lateral movement and chattering by a wrench, c, which is turned so as to bind the drill in the slot of the holder. the relative position of the tool and work is shown in figs. , , , and ; fig. shows the position for brass; fig. for iron and steel; fig. the relative position of the engine rest tool and its work; and fig. the position of the tool for soft metal and wood. in all of these cases the point of the tool is above the center of the work. in the matter of the adjustment of the tool, as well as in all other operations referred to, experiment is recommended as the best means of gaining valuable knowledge in the matter of turning metals. rotary cutters. the saving of files, time, materials, and patience, by the employment of such rotary cutters as may be profitably used in connection with a foot lathe, can hardly be appreciated by one who has never attempted to use this class of tools. it is astonishing how much very hard labor may be saved by means of a small circular saw like that shown in fig. . this tool, like many others described in this series of articles, can, in most instances, be purchased cheaper than it can be made, and the chances are in favor of its being a more perfect article. however, it is not so difficult to make as one might suppose. a piece of sheet steel may be chucked upon the face plate, or on a wooden block attached to the face plate, where it may be bored to fit the saw mandrel, and cut in circular form by means of a suitable hand tool. it may then be placed upon the mandrel and turned true, and it is well enough to make it a little thinner in the middle than at the periphery. [illustration: rotary cutting tools.] there are several methods of forming the teeth on a circular saw. it may be spaced and filed, or it may be knurled, as shown in fig. , and then filed, leaving every third or fourth tooth formed by the knurl, or it may, for some purposes, be knurled and not filed at all. another way of forming the teeth is to employ a hub, something like that used in making chasers, as shown in fig. , the difference between this hub and the other one referred to, is that the thread has one straight side corresponding with the radial side of the tooth. the blank from which the saw is made is placed on a stud projecting from a handle made specially for the purpose, and having a rounded end which supports the edge of the blank, as the teeth are formed by the cutters on the hub. the saw, after the teeth are formed, may be hardened and tempered by heating it slowly until it attains a cherry red, and plunging it straight down edgewise into cool, clean water. on removing it from the water it should be dried, and cleaned with a piece of emery paper, and its temper drawn to a purple, over a bunsen gas flame, over the flame of an alcohol lamp, or over a hot plate of iron. the small saw shown in fig. is easily made from a rod of fine steel. it is very useful for slotting sheet brass and tubes, slotting small shafts, nicking screws, etc. being quite small it has the advantage of having few teeth to keep in order, and it may be made harder than those of larger diameter. a series of them, varying in diameter from one eighth to three eighths of an inch, and varying considerably in thickness, will be found very convenient. these cutters or saws, with the exception of the smaller one, may be used to the best advantage in connection with a saw table, like that shown in fig. . this is a plane iron table having a longitudinal groove in its face to receive the guiding rib of the carriage, shown in fig. , and a transverse groove running half way across, to receive a slitting gauge, as shown in fig. . the table is supported by a standard or shank, which fits into the tool-rest socket. the saw mandrel is supported between the centers of the lathe, and the saw projects more or less through a slot formed in the table. the gauge serves to guide the work to be slotted, and other kinds of work may be placed on or against the carriage, shown in fig. . it is a very simple matter to arrange guiding pieces for cutting at any angle, and the saw table may be used for either metal or wood. the saws for wood differ from those used for metal; the latter are filed straight, the former diagonally or fleaming. among the many uses to which metal saws may be applied we mention the slitting of sheet metals, splitting wires and rods, slotting and grooving, nicking screws, etc. fig. shows a holder for receiving screws to be nicked. it is used in connection with the saw table, and is moved over the saw against the gauge. to facilitate the removal of the screws the holder may be split longitudinally and hinged together. another method of nicking screws is illustrated by fig. . a simple lever, fulcrumed on a bar held by the tool post, is drilled and tapped in the end to receive the screw. after adjusting the tool all that is required is to insert the screw and press down the handle so as to bring the screw head into contact with the saw. where a lathe is provided with an engine rest, the cutter shown in fig. , mounted on the mandrel shown in fig. , is very useful; it is used by clamping the work to the slide rest and moving it under the cutter by working the slide rest screw. to make a cutter of this kind is more difficult than to make a saw, and to do it readily a milling machine would be required. it may be done, however, on a plain foot lathe, by employing a v-shaped cutter and using a holder (fig. ) having an angular groove for receiving the cylinder on which the cutting edges are formed. the blank can be spaced with sufficient accuracy, by means of a fine pair of dividers, and after the first groove is cut there will be no difficulty in getting the rest sufficiently accurate, as a nib inserted in the side of the guide enters the first groove and all of the others in succession and regulates the spacing. one of the best applications of this tool is shown in the small engraving. in this case a table similar to the saw table before described is supported in a vertical position, and arranged at right angles with the cutter mandrel. the mandrel is of the same diameter as the cutter, and serves as a guide to the pattern which carries the work to be operated upon. the principal use of this contrivance is to shape the edges of curved or irregular metal work. the casting to be finished is fastened--by cement if small, and by clamps if large--to a pattern having exactly the shape required in the finished work. [illustration: metal shaping.] by moving the pattern in contact with the table and the mandrel, while the latter revolves, the edges of the work will be shaped and finished at the same time. by substituting a conical cutter for a cylindrical one, the work may be beveled; by using both, the edge may be made smooth and square, while the corner is beveled. the tool shown in fig. might properly be called a barrel saw. it is made by drilling in the end of a steel rod and forming the teeth with a file. to avoid cracking in tempering a small hole should be drilled through the side near the bottom of the larger hole. to insure the free working of the tool it should be turned so that its cutting edge will be rather thicker than the position behind it. this tool should be made in various sizes. tools for gear cutting and also cutters for wood have not been mentioned in this paper; as they are proper subjects for separate treatment. wood working. it is not the intention of the writer to enter largely into the subject of wood working, but simply to suggest a few handy attachments to the foot lathe which will greatly facilitate the operations of the amateur wood worker, and will be found very useful by almost any one working in wood. it is not an easy matter to split even thin lumber into strips of uniform width by means of a handsaw, but by using the circular saw attachment, shown in fig. , the operation becomes rapid and easy, and the stuff may be sawed or slit at any desired angle or bevel. the attachment consists of a saw mandrel of the usual form, and a wooden table supported by a right angled piece, a, of round iron fitted to the toolpost and clamped by a wooden cleat, b, which is secured to the under side of the table, split from the aperture to one end, and provided with a thumbscrew for drawing the parts together. by means of this arrangement the table may be inclined to a limited angle in either direction, the slot through which the saw projects being enlarged below to admit of this adjustment. [illustration: woodworking attachments for the foot lathe.] the back of the table is steadied by a screw which rests upon the back end of the tool rest support, and enters a block attached to the under side of the table. the gauge at the top of the table is used in slitting and for other purposes which will be presently mentioned, and it is adjusted by aid of lines made across the table parallel with the saw. for the purpose of cross cutting or cutting on a bevel a thin sliding table is fitted to slide upon the main table, and is provided with a gauge which is capable of being adjusted at any desired angle. for cutting slots for panels, etc., thick saws may be used, or the saw may be made to wabble by placing it between two beveled washers, as shown in fig. . the saw table has an inserted portion, c, held in place by two screws which may be removed when it is desired to use the saw mandrel for carrying a sticker head for planing small strips of moulding or reeding. the head for holding the moulding knives is best made of good tough brass or steam metal. the knives can be made of good saw steel about one-eighth inch thick. they may be filed into shape and afterward tempered. they are slotted and held to their places on the head by means of quarter-inch machine screws. it is not absolutely necessary to use two knives, but when only one is employed a counterbalance should be fastened to the head in place of the other. all kinds of moulding, beading, tonguing, and grooving may be done with this attachment, the gauge being used to guide the edge of the stuff. if the boards are too thin to support themselves against the action of the knives they must be backed up by a thick strip of wood planed true. the speed for this cutter head should be as great as possible. fig. shows an attachment to be used in connection with the cutter head and saw table for cutting straight, spiral, or irregular flutes on turned work. it consists of a bar, d, carrying a central fixed arm, and at either end an adjustable arm, the purpose of the latter being to adapt the device to work of different lengths. the arm projecting from the center of the bar, d, supports an arbor having at one end a socket for receiving the twisted iron bar, e, and at the other end a center and a short finger or pin. a metal disk having three spurs, a central aperture, and a series of holes equally distant from the center and from each other, is attached by its spurs to the end of the cylinder to be fluted, and the center of the arbor in the arm, d, enters the central hole in the disk while its finger enters one of the other holes. the opposite end of the cylinder is supported by a center screw. a fork attached to the back of the table embraces the twisted iron, e, so that as the wooden cylinder is moved diagonally over the cutter it is slowly rotated, making a spiral cut. after the first cut is made the finger of the arbor is removed from the disk and placed in an adjoining hole, when the second cut is made, and so on. figs. and show a convenient and easily made attachment for moulding the edges of irregular work, such as brackets, frames, parts of patterns, etc. it consists of a brass frame, f, supporting a small mandrel turning at the top in a conical bearing in the frame, and at the bottom upon a conical screw. a very small grooved pulley is fastened to the mandrel and surrounded by a rubber ring which bears against the face plate of the lathe, as shown in the engraving. the frame, f, is let into a wooden table supported by an iron rod which is received by the tool rest holder of the lathe. the cutter, g, is made by turning upon a piece of steel the reverse of the required moulding, and slotting it transversely to form cutting edges. the shank of the cutter is fitted to a hole in the mandrel and secured in place by a small set screw. the edge of the work is permitted to bear against the shank of the cutter. should the face plate of the lathe be too small to give the required speed, a wooden disk may be attached to it by means of screws and turned off. figs. , , and represent a cheaply and easily made scroll saw attachment for the foot lathe. it is made entirely of wood and is practically noiseless. the board, h, supports two uprights, i, between which is pivoted the arm, j, whose under side is parallel with the edge of the board. a block is placed between the uprights, i, to limit the downward movement of the arm, and the arm is clamped by a bolt which passes through it and through the two uprights and is provided with a wing nut. a wooden table, secured to the upper edge of the board, h, is perforated to allow the saw to pass through, and is provided with an inserted hardwood strip which supports the back of the saw, and which may be moved forward from time to time and cut off as it becomes worn. the upper guide of the saw consists of a round piece of hard wood inserted in a hole bored in the end of the arm, j. the upper end of the saw is secured in a small steel clamp pivoted in a slot in the end of a wooden spring secured to the top of the arm, j, and the lower end of the saw is secured in a similar clamp pivoted to the end of the wooden spring, k. fig. is an enlarged view showing the construction of clamp. the relation of the spring, k, to the board, h, and to the other part is shown in fig. . it is attached to the side of the board and is pressed upward by an adjusting screw near its fixed end. the saw is driven by a wooden eccentric placed on the saw mandrel shown in figs. and , and the spring, k, always pressed upward against the eccentric by its own elasticity, and it is also drawn in an upward direction by the upper spring. this arrangement insures a continuous contact between the spring, k, and the eccentric, and consequently avoids noise. the friction surfaces of the eccentric and spring may be lubricated with tallow and plumbago. the eccentric may, with advantage, be made of metal. the tension of the upper spring may be varied by putting under it blocks of different heights, or the screw which holds the back end may be used for this purpose. the saw is attached to the lathe by means of an iron bent twice at right angles, attached to the board, h, and fitted to the tool rest support. the rear end of the sawing apparatus may be supported by a brace running to the lower part of the lathe or to the floor. the simple attachments above described will enable the possessor to make many small articles of furniture which he would not undertake without them, and for making models of small patterns they are almost invaluable. * * * * * a new method of keeping mechanical drawings.[ ] [footnote : a paper by chas. t porter, read before the american society of mechanical engineers.] the system of keeping drawings now in use at the works of the southwark foundry and machine company, in philadelphia, has been found so satisfactory in its operation that it seems worthy of being communicated to the profession. the method in common use, and which may be called the natural method, is to devote a separate drawer to the drawings of each machine, or of each group or class of machines. the fundamental idea of this system, and its only one, is, keeping together all drawings relating to the same subject matter. every draughtsman is acquainted with its practical working. it is necessary to make the drawing of a machine, and of its separate parts, on sheets of different sizes. the drawer in which all these are kept must be large enough to accommodate the largest sheets. the smaller ones cannot be located in the drawer, and as these find their way to one side or to the back, and several of the smallest lie side by side in one course, any arrangement of the sheets in the drawer is out of the question. the operation of finding a drawing consists in turning the contents of the drawer all up until it is discovered. in this way the smaller sheets get out of sight or doubled up, and the larger ones are torn. no amount of care can prevent confusion. various plans have been adopted in different establishments intended to remedy this state of things, but it is believed that none has been hit upon so convenient, in all respects, as the one now to be presented. the idea of keeping together drawings relating to the same machine, or of classifying them according to subjects in any way, is entirely abandoned, and in place of these is substituted the plan of keeping together all drawings that are made on sheets of the same size, without regard to the subject of them. nine sizes of sheets were settled upon, as sufficient to meet our requirements, and on a sheet that will trim to one of these sizes every drawing must be made. they are distinguished by the first nine letters of the alphabet. size a is the antiquarian sheet trimmed, and the smaller sizes will cut from this sheet, without waste, as follows: a, × in.; b, × in; c, × in.; d, × in.; e ½× in.; f, ½× in.; g, × in.; h, ½× in.; i, × in. the drawers for the different sizes are made one inch longer and wider than the sheets they are to contain, and are lettered as above. those of the same size, after the first one, are distinguished by a numeral prefixed to the letter. the back part of each drawer is covered for a width of from six to ten inches, to prevent drawings, and especially tracings, from slipping over at the back. the introduction of the blue printing process has quite revolutionized the drawing office, so far at least as we are concerned. our drawings are studies, left in pencil. when we can find nothing more to alter, tracings are made on cloth. these become our originals, and are kept in a fire-proof vault. this system is found admirably adapted to the plan of making a separate drawing for each piece. the whole combined drawing is not generally traced, but the separate pieces are picked out from it. all our working copies are blue prints. each drawer contains fifty tracings. they are two and a half inches deep, which is enough to hold several times as many, but this number is quite all that it is convenient to keep together. we would recommend for these shallower drawers. each drawing is marked in stencil in the lower right hand corner, and also with inverted plates in the upper left hand corner, with the letter and number of the drawer, and its own number in the drawer, as, for example, f-- ; so that whichever way the sheet is put in the drawer, this appears at the front right hand corner. the drawings in each drawer are numbered separately, fifty being thus the highest number used. for reference we depend on our indices. each tracing, when completed, is entered under its letter in the numerical index, and is given the next consecutive number, and laid in its place. from this index the title and the number are copied into other indices, under as many different headings as possible. thus all the drawings of any engine, or tool, or machine whatever, become assembled by their titles under the heading of such particular engine, or tool, or machine. so also the drawings of any particular part, of all sizes and styles, become assembled by their titles under the name of such piece. however numerous the drawings, and however great the variety of their subjects, the location of any one is, by this means, found as readily as a word in a dictionary. the stencil marks copy, of course, on the blue prints, and these when not in use are kept in the same manner as the tracings, except that only twenty-five are placed in one drawer. we employ printed classified lists of the separate pieces constituting every steam engine, the manufacture of which is the sole business of these works, and on these, against the name of every piece, is given the drawer and number of the drawing on which it is represented. the office copies of these lists afford an additional mode of reference and a very convenient one, used in practice almost exclusively. the foreman sends for the prints by the stencil marks, and these are thus got directly without reference to any index. they are charged in the same way, and reference to the numerical index gives the title of any missing print. we find the different sizes to be used quite unequal. the method of making a separate tracing of each piece, which we carry to a great extent, causes the smaller sizes to multiply quite rapidly. we are marking our patterns with the stencil of the drawing of the same piece; and also, gauges, templets, and jigs. it is found best to permit the sheets to be put away by one person only, who also writes up the indices, which are kept in the fire proof. we were ourselves surprised at the saving of room which this system has effected. probably less than one-fourth the space is occupied that the same drawings would require if classified according to subjects. the system is completely elastic. work of the most diverse character might be undertaken every day, and the drawings of each article, whether few or many, would find places ready to receive them. * * * * * achard's electric brake. [illustration: elevation.] [illustration: plan. achard's electric brake--eastern railway of france.] the merits of a brake in which electric apparatus is used, that has been adopted by one large railway company, and is about to be used on the state railways, as well as the fact that arrangements are being made to introduce it in england, demand consideration. it may be that modifications will, under different circumstances, be introduced, or that the system will ultimately be found too cumbersome or too delicate, but before criticism it is necessary to know something of the apparatus. we therefore endeavor to give somewhat in detail the arrangement adopted by m.l. regray, chief engineer of the chemin de fer de l'est, the electrical system being that of m. achard. an electro-magnet, a, is suspended on a hinged axis, so that the poles of the magnet have for armatures cylinders of metal fixed upon the axle of the carriage. suppose now the poles, d d, of the magnet brought into contact with the revolving armatures, the friction between them causes the magnet to revolve. the chain attached to the brake is fixed to the extended axle of the magnet, and consequently when that axle revolves is wound up, bringing the brakes upon the wheels. the friction between the poles and the armature depends upon the strength of the magnet, and this can be regulated at will from a maximum to a minimum. but it will be well to trace the whole action. the electric current may be obtained by means of planté secondary cells charged by daniell's cells--in other words, one or two daniell's cells are constantly in action charging three or six planté cells, and it is the planté cells that are called into action to electrify the magnet. the battery is carried in a box in the brake van. the engineers, however, seem to prefer that the current be obtained by means of a small gramme machine, driven direct by a brotherhood three-cylinder engine, the steam for which is obtained from the locomotive. the velocity and hence the current of the gramme machine can be regulated, and so the action of the brakes. m. achard prefers the planté cells; he informs us that he has tried the faure battery, but the results obtained were not satisfactory. the regulator, r², consists of a cylinder of wood around which, as shown, wire is wound. the length of this wire in the circuit, increasing as it does the resistance of the circuit, determines the current to the electro-magnet. the action is as follows: when it is necessary to apply the brakes, a simple pressure of a key or the turn of a handle sends the electric current into the wires of the electro-magnet. an attraction immediately takes place, and the poles and armatures are brought into contact. the friction between these causes the revolution of the magnet, the winding of the chain around the axle, and the application of the brakes. the whole of the brakes of the train enter into action at one and the same time. the brakes are taken off by stopping the current, and a small spring pulls and keeps the magnet from the armatures. a frame--also carriages--fitted with this brake, are shown by the compagnie des chemins de fer de l'est, which company also shows several other pieces of interesting apparatus, one of which is a carriage fitted with elaborate mechanism, in which electricity plays, perhaps, but a subsidiary part, to obtain the traction of the train under varying circumstances, the pressure on the buffers when stopping, and various phenomena connected with the engine.--_the engineer._ * * * * * electricity; what it is, and what may be expected of it.[ ] [footnote : a paper read before the engineers' society of western pennsylvania, nov. , .] by jacob reese in the consideration of this subject it is not my purpose to review the steps of discovery and development of electrical phenomena, but the object of this paper is an effort to explain what electricity is; and having done this, to deduce some reasonable conclusions as to what may be expected of it. and while i am profoundly sensible of the importance of the subject, and the difficulties attending its consideration, still with humble boldness i present this paper and ask for it a serious and careful consideration, hoping that the discussion and investigation resulting therefrom may add to our knowledge of physical science. it is now a well established fact that matter, _per se_, is inert, and that its energy is derived from the physical forces; therefore all chemical and physical phenomena observed in the universe are caused by and due to the operations of the physical forces, and matter, of whatever state or condition it may be in, is but the vehicle through or by which the physical forces operate to produce the phenomena. there are but two physical forces, i.e., the force of attraction and the force of caloric. the force of attraction is inherent in the matter, and tends to draw the particles together and hold them in a state of rest. the force of caloric accompanies the matter and tends to push the particles outward into a state of activity. the force of attraction being inherent, it abides in the matter continuously and can neither be increased nor diminished; it, however, is present in different elementary bodies in different degrees, and in compound bodies relative to the elements of which they are composed. the force of caloric is mobile, and is capable of moving from one portion of matter to another; yet under certain conditions a portion of caloric is occluded in the matter by the force of attraction. that portion of caloric which is occluded (known by the misnomer, latent heat) i shall call _static caloric_, and that portion which is in motion, _dynamic caloric_. the force of attraction, as i have said, tends to draw the particles of matter together and hold them in a state of rest; but as this force is inherent, the degree of power thus exerted is in an inverse ratio to the distance of the particles from each other. the effective force so exerted is always balanced by an equivalent amount of the force of caloric, and that modicum of caloric so engaged in balancing the effective force of attraction is static, because occluded in that work. in solid or fluid bodies, where the molecules are held in a local or near relation to each other, the amount of static caloric will be in direct proportion to the effective force of attraction, but in gaseous bodies the static caloric is in an inverse ratio to the effective force of attraction; hence the amount of static caloric present in solid and fluid bodies will be greatest when the molecules are nearest each other, and greatest in gaseous bodies when the molecules are furthest apart. caloric, whether static or dynamic, is not phenomenal; therefore the phenomena of light, temperature, incandescence, luminosity, heat, cold, and motion, as well as all other phenomena, are due to the movement of matter caused by the physical forces. thus we find that _temperature is a phenomenal measure of molecular velocity_, as we consider weight to be the measure of matter. an increase of temperature denotes an increased molecular velocity, and this in solid and liquid bodies unlocks a portion of the static caloric and converts it into dynamic caloric, while an increased temperature of gases occludes additional caloric, thus converting dynamic into static caloric; and a reduction of molecular activity reverses this action. from this we see that a change of temperature either converts static to dynamic or dynamic to static caloric. thus we find that the amount of static caloric which a body possesses is in direct relation to its temperature, but, as i have already explained, temperature is a phenomenal indication of molecular velocity, and as increased velocity separates the molecules to a greater distance, which reduces the effective force of attraction and unlocks a portion of caloric, it will be seen that the separation of the molecules from any other cause will have the same effect. i desire now to explain a second method by which the molecules are separated and static caloric is changed to dynamic caloric. it is not definitely known how much static caloric is occluded in either of the elementary bodies, but it is believed that hydrogen possesses the greatest amount and oxygen the least. now if we take a molecule of hydrogen containing two atoms, and under proper conditions interpose these atoms between atoms of oxygen (one molecule), the phenomenon of combustion is exhibited, and a molecule of water is formed containing atoms; and if one pound of hydrogen is thus consumed, the atoms of hydrogen are separated from each other to such a distance by the interposing atoms of oxygen as to unlock , units c. of static, and convert it into dynamic caloric. and if we thus bring a molecule of carbon containing atoms in contact with a molecule of oxygen of atoms, combustion ensues and a molecule of carbonic oxide of atoms is formed, and if we then present another molecule of oxygen, combustion again takes place, and a molecule of carbonic acid, containing atoms, is produced. now, in the combustion of one pound of carbon in this manner, when the carbon is converted into carbonic oxide (co), , units c. of static is converted into dynamic caloric; and when this co is converted into carbonic acid (co_{ }) , additional units c. are unlocked. thus by the combustion of one pound of carbon to co_{ }, , units c. of static caloric are changed to dynamic caloric. when caloric is thus unlocked from its occlusion it escapes with great velocity until an equilibrium is attained, and in doing so it pushes the particles of matter out of its path. in solid bodies this produces such a high degree of molecular movement as to exhibit the phenomena of incandescence and luminosity, and in liquids increased mobility, while in gases the molecular activity may be so great as to produce the phenomena of sound and light; and the more rapidly combustion takes place the greater will be the volume and velocity of dynamic caloric escaping therefrom; consequently with a slow combustion, the phenomena produced by dynamic caloric will be different from those exhibited at a high degree. combustion, as i have before shown, is merely the oxidation of the material; nothing is _consumed_ nor annihilated, and, the phenomena vary with the velocity of oxidation. now, if we take one pound of zinc and place it in the acid cell of an electric battery, the oxygen of the acid attacks the zinc and oxide of zinc is formed. in this operation the zn molecule containing atoms is united with one molecule of oxygen of atoms, forming a molecule of oxide of zinc (zno) of atoms; and owing to the comparatively small number of oxygen atoms interposed between the atoms of zinc, only , units c. of static caloric are unlocked to the pound of zinc, and the velocity of oxidation is so low, and the insulation of the vessel so perfect, that the dynamic caloric is caused to flow outward through the copper wire. electricity.--what is it? why, it is dynamic caloric. now let us take this oxide of zinc (zno) and place it with charcoal in a reducing apparatus which stands on an insulated table; the apparatus is then heated, the carbon vaporizes, and this vapor of carbon (c) robs the oxide of zinc (zno) of its oxygen, leaving metallic zinc (zn) and carbonic oxide (co). now, for every pound of zinc so formed , units c. of static caloric are transferred from the charcoal to the zinc and occluded in it. hence we find that the , units c. of caloric which we took out of the zinc, and which we call electricity, is nothing else but the , units of static caloric which was contained in the charcoal and from it set free by oxidation and transferred to the zinc in the smelting process. let us follow this matter a little further. charcoal is made by burning wood under such conditions as eliminate the water and hydrogen and leave the carbon as a residuum which we call charcoal. thus we find that the caloric contained in the charcoal, transferred from the charcoal to the zinc, and from it developed into what we call electricity, was previously embodied in the wood; and if we study the laws of vegetation, we find that the atmosphere being charged with carbonic acid (co_{ }), the leaves of plants, shrubs, and trees, breathing, take in the co_{ }, the sun rays decompose the co_{ }, set free the oxygen, and supply the necessary amount of caloric for the condensed state of the carbon. thus we find that the force which we term electricity, developed from the oxidation of zinc, or any other matter, by oxidation, primarily comes from the sun rays. coal is generally supposed to be of vegetable origin, and the caloric occluded in it is derived from the same source as that embodied in charcoal. now when we burn coal under a steam boiler, the carbon and hydrogen are oxidized, and the static caloric set free. a portion of this caloric passes through the shell or tubes of the boilers, and increases the molecular velocity of the water; increased activity of the molecules tends to separate them to a greater distance from each other. when the molecular velocity of the water acquires the degree indicated by a temperature of degrees f., the water passes from the fluid to the gaseous state, and in doing so expands to , times its bulk. now if the steam so developed be confined under a pressure of pounds to the square inch, the water will not vaporize until a molecular velocity is attained indicated by a temperature of ° f. (spons' "engineering," d , page ), and then the expansion is only times its bulk. by using this steam, in a steam engine, the caloric in the steam tends to push the molecules of which it is composed into an ultimate expansion of , times the bulk of the water from which it was generated, and this force acts upon the piston and does the work. thus we see that the steam engine is driven by the same force which produces the phenomena accredited to electricity. i have already shown that in what we term combustion not a particle of the ponderable matter is annihilated. combustion is but a phenomenon resulting from a rearrangement of the particles, and so it is with the imponderable physical force caloric; it is not consumed when light and heat are produced, nor converted into power, as we are sometimes told. but whatever the phenomena produced, the aggregate amount of static and dynamic caloric is always and ever the same. if we consider the ritter-plant-faure-battery, which is mentioned as storing electricity, we find that the phenomena exhibited by the use of this apparatus are produced by the same factor. the battery is composed of two sheets of lead, which are covered with a layer of minium (pb o ). the sheets are laid one upon the other with an intervening layer of felt. the pack is then rolled up in a spiral form and placed in a vessel containing acidulated water. one of the plates is connected with the positive, and the other plate with the negative pole of a battery or generator. when the current of electricity enters the battery, the pb o on the positive plate is reduced to pb, and the oxygen so set free attacks the pb o on the negative plate, and oxidizes it to pbo . in this chemical action, caloric is occluded in the pb and unlocked in the pbo , but a much greater amount of caloric is locked up than is unlocked, although the amount of oxygen used in both cases is precisely the same, which has been fully explained in the oxidation of carbon. now after the battery has been thus charged and the wires disengaged, the chemical action ceases for want of the reducing agent (_dynamic caloric_), and the apparatus may be held at rest, or transported to any distance required. when it is desired to utilize the force thus stored, the poles are changed by grounding the positive wire, and attaching the other to the conduit through which the electricity is to flow. the chemical action is thus reversed, and the pbo is reduced to pb o , the oxygen thus set free attacks the pb on the other plate, oxidizing it to pb o , thus unlocking all the caloric which was occluded by the first action. in a battery of this kind weighing pounds, we are informed by sir william thomson, that one million foot pounds of force may be stored, and again set free for use. thus we find that the principle upon which the faure battery is formed is not new, and the prime factor producing the phenomena is the same as has been shown to have caused all other phenomena referred to, and indeed the principle is the same as now employed by the author in the basic dephosphorizing process, i.e., caloric is occluded in phosphorus by smelting in a blast furnace, and unlocked in the converter, for the purpose of securing the fluidity of the metal during treatment. the difference being, that one is done by non-luminous, while the other is by luminous combustion. if we consider the phenomenon of light, we find that it is due to the same force. as before stated, when we oxidize carbon, or hydrogen, as in the rapid combustion of wood, oil, or coal, the escaping caloric flies off with such great speed as to cause the molecules in the circumambient medium to assume a velocity which exhibits luminosity. thus the light produced by burning candles, oil, gas, wood, and coal, is caused by the same prime factor, dynamic caloric. the force of caloric is imponderable and invisible, and is only known by its effects. we do know that it is occluded in metals and other material, because we can unlock it and set it free, or we can transfer it from one body to another, and by measuring its effects, we can determine its quantity. we know that it prefers to travel over one vehicle more than another, and by this knowledge we are able to insulate it, and thus conduct it in any direction desired. the materials through which it passes with the greatest freedom are called conductors, and the materials which most retard its passage, non-conductors; but these terms must be taken in a comparative sense only, as in fact there are no absolute non-conductors of dynamic caloric, or of what we call electricity. the dynamo-electric generator simply draws the dynamic caloric from the air or earth, or both, and confines it in an insulated path. now if that path be a no. wire, the conduit may be sufficient to permit the caloric to pass without increasing the molecular velocity of the metal to an appreciable degree, but if we cut the no. wire and insert a piece of no. platinum wire in the path, the amount of caloric flowing through the no. wire cannot pass through the no. wire, and the resistance so caused increases the molecular velocity of the no. wire to such degree as to exhibit the phenomenon of incandescence, and this is the incandescent electric light. and if we consider the carbon light, we find that the current of caloric, in passing from one pencil to the other, produces a molecular velocity of luminosity in the adjoining atmosphere, and in addition a portion of the carbon is consumed, which sets free an additional amount of caloric, at a very high velocity, hence the intensity of the carbon electric light is largely due to the dynamic caloric unlocked from the pencils, and thus we find that the electric light produced by either method is due to the action of dynamic caloric. taking this theory based upon physical science, and the facts which we know pertaining to electricity, i conceive that caloric exists in two conditions. _static caloric_ is what we call _latent heat_, and _dynamic caloric_ is what we call _electricity_. therefore what may we expect of it (electricity) is merely a matter of economy in the development and utilization of dynamic caloric; in other words, can we unlock static caloric by non-luminous combustion, and thus develop _dynamic caloric as a first power_ more economically per foot pound than we now do or can hereafter do by luminous combustion? second, can we utilize water and wind for the production of _dynamic caloric as a first power_? third, can we utilize the differential tension of dynamic caloric in the earth and the atmosphere as _a first power_? fourth, will it pay to use luminous combustion as a first power to generate dynamic caloric as _a second power_? what may we expect of it. let us take the steam engine, and see what we are now doing by luminous combustion. good pittsburg coal contains per cent. of carbon, per cent. of hydrogen, per cent. of oxygen and per cent. of ash; we therefore have in one pound of such coal: , × , × --------- = ----------- = , units in carbon. , × , × , units in hydrogen. ---------- = ---------- = ------ , units in coal. , × [ ] = , , foot pounds of energy is occluded in the static caloric contained in one pound of such coal. [footnote : dr. joule--foot pounds in one unit.] a horse-power is estimated as capable of raising , pounds one foot high per minute, and for this reason it is termed , foot pounds per minute. so we have , × = , , foot pounds per hour, as a horse-power. the best class of _compound condensing_ engines,[ ] with all the modern improvements, require . pounds of coal per h.p. per hour. thus we have-- , , × . ................. , , foot pounds in one h.p. ............. , , ---------- foot pounds lost per h.p. .......... , , per cent utilized per h.p. .............. . per cent lost per h.p. ................. . ------ . [footnote : "american engineer," vol. ii., no. , page .] in the ordinary practice of stationary non-condensing engines, from three to four pounds of coal are required per horse-power per hour. now, taking the best of this class at pounds, we have-- , , × = , , one h.p. , , ---------- loss per h.p. , , per cent utilized per h.p. . per cent lost per h.p. . ------ . from these facts it may be assumed that after making due allowance for variable qualities of the coal, the steam engine process, as at present practiced, will not utilize more than from to per cent. of the energy contained in the fuel used. it will thus be seen that the process of converting static to dynamic caloric by luminous combustion, by means of the steam engine, is an exceedingly wasteful and costly method, and leaves much room for economy. taking an ordinary grade of petroleum as consisting of per cent. hydrogen, carbon, oxygen, nitrogen and ash, we have as its energy in foot pounds per pound of oil-- , × } ----------- = , h. } } } , units. , × } ----------- = , c. } } , × = , , foot pounds. thus, while our best coal contains twelve million, the petroleum contains fifteen million foot pounds of occluded energy in each pound, which is equal to , , foot pounds, or horse power for one hour, from one gallon of such oil. at present electricity is generated by two methods, and both of these are _second powers_. metals are smelted by luminous combustion as a first power, and then oxidized by non-luminous combustion as a _second power_, and coal is consumed by luminous combustion, by which steam is generated as a first power, to drive a dynamo-generator whereby electricity is obtained as a _second power_. now, of the two methods, the latter is much the cheaper, and as i have shown that the best compound condensing engines only utilize . , and a fair average single cylinder condensing engine only utilizes . per cent. of the energy of the fuel consumed, and as at the best not over per cent. of the foot pounds obtained from the engine can be utilized as electricity, from which we must deduct loss by friction, etc., it will be readily seen that not more than per cent. of the energy of the fuel can be developed by the dynamo-generator as electricity by the present method. the great want of the present age is a process by which the static caloric of carbon or a hydrocarbon maybe set free by non-luminous combustion; or, in other words, a process by which coal or oil may be oxidized at a low degree, within an insulated vessel; if this can be accomplished (and i can see no reason why we should not look for such invention), we would be able to produce from twelve to fifteen million foot pounds of energy (electricity) from one pound of petroleum, or from ten to twelve million foot pounds from one pound of good coal, which would be a saving of from to per cent. of present cost, and leave the steam engine for historical remembrance. electricity may be generated by water or wind power to great advantage, and conveyed to a distance for motive power. the practicability of generating electricity at niagara by which to propel trains to new york and return may be considered almost settled; and i conceive a second invention of importance which is now needed is an apparatus by which the rising and falling tides may be utilized for driving dynamo machines, by which electricity may be generated for lighting the coast cities, and it is not unreasonable to expect that such an apparatus will soon be provided; and in such an event gas companies would suffer. it is a well known fact among electricians that the volume and tension of electricity vary both in the earth and in the atmosphere at different sections of the earth's surface, and i conceive that we may yet find means of utilizing this differential tension of electricity; indeed, it is reported that during a recent storm the wires of an ocean cable were grounded at both ends and a sufficient current for all practical purpose flowed from the european to the american continent, with all batteries removed, showing that the tension was so much greater in europe as to cause the electricity to flow through the copper cable to this side in preference to passing through the earth or the sea. it is also said that during an east-going storm it was found impossible to work the telegraph lines between new york and buffalo, but on taking off the batteries at both ends and looping the ends of the wire in the air, that a constant current of electricity passed from buffalo to new york, and the line was kept in constant use in that direction without any battery connection until the storm abated. now, how far or to what advantage we may be able to utilize this differential tension of electricity in the earth and the air, we cannot now say; but i think that we may justly look for valuable developments in this direction. if, as i verily believe, a process will soon be discovered by which dynamic caloric can be produced by the oxidation of petroleum with non-luminous combustion in an insulated chamber, as we now oxidize zinc, electricity will then be obtained from so small a weight, and at such a low cost, as to insure aerial navigation beyond a doubt. not with balloons and their cumbrous inflations, but with machines capable of carrying the load, and traveling by displacement of the air at high velocities. therefore we may expect that aerial navigation will be developed in the near future to be one of the greatest enterprises of the world. and lastly, will it pay to use luminous combustion as a first power for generating dynamic caloric for use as a second power, as is now practiced? at the university of pennsylvania, in philadelphia, gas is consumed in an otto gas engine, which drives a gramme generator; and the lecture room is lighted with electricity, and i am informed that the light is both better _and cheaper_ than when they used the gas in the ordinary gas burners. hence we may expect to see gas consumed to advantage for producing electric lights. considering the difficulties of transmitting steam power to a considerable distance, and the comparative great cost of running small engines, it is more than likely that electricity as at present generated will be found to be economical for driving small motors. having thus endeavored to explain what electricity is, and the laws which govern the occlusion of static caloric, and the development of dynamic caloric (electricity), in conclusion i call the attention of the inventors of the age to the great need of a process for oxidizing coal or oil at a low degree, within an insulated vessel. with such an invention electricity would be obtained at such a low cost that it would be used exclusively to light and heat our houses, to smelt, refine, and manipulate our metals, to propel our cars, wagons, carriages, and ships, cook our food, and drive all machinery requiring motive power. * * * * * electric light apparatus for photographic purposes. by a.j. jarman. for some time past it has been the desire of many photographers to have at hand a ready means of producing a powerful and highly actinic artificial light, suitable for the production of negatives, and easily controllable. several forms of apparatus have been designed, and i believe have been, to a certain extent, employed successfully in portraiture. but it has been well known for many years that the electric light was just the light that would answer the photographer's requirements, owing to its possessing great actinic power; but the cost of its production was too great for general adoption; indeed, such might be said of it now as far as dynamo-electric machines and steam or gas motors are concerned, for the majority of photographers. it is true that several influential photographers have already adopted the use of the electric light for portraiture, but the primary cost of the apparatus employed by these firms is far beyond the reach of most portraitists. the apparatus about to be described is one that has been carefully worked out to meet the wants of the photographer in almost every particular; in fact, with this apparatus, portraits can, and have been, produced in an ordinary sitting room, as good and as perfect as if taken in a well-lighted studio. [illustration: fig. .] the generator of the electric current consists of a series of voltaic elements of zinc and carbon--forty-eight in number--these elements being made up of ninety-six zinc plates and forty-eight carbon plates; thus the generator consists of forty-eight voltaic elements arranged in rows of twelve; they are all carefully screwed upon suitable bars of wood, and these bars are joined by other cross bars, which bind the whole in a compact form; the battery being suitably connected so as to produce a current of very high electro-motive force, and so arranged over their exciting trough that the plates can be raised or lowered at will, as seen in fig. , which will explain itself almost at first sight. the troughs are made of mahogany, put together with brass screws, and well saturated with an insulating compound which also makes them acid proof; the cells are charged with a saturated solution of bichromate of potash, to which has been added twenty fluid ounces of sulphuric acid to each gallon. [illustration: fig. .] to produce the electric current, all that is needed is to lower these suspended elements down into the trough, having previously connected the wires as shown in fig. , to the electric lamp, fig . at once a light starts up, between the carbon pencils, of a thousand-candle power or more. with a light of this power, a large head on cabinet or carte size plate may be produced in three or four seconds. the generator occupies a floor space of three feet six inches by two feet, and stands two feet six inches high. the cells will cost s. to charge, and will produce upward of sixty negatives before being exhausted. all that is necessary, in recharging, is to lift the elements up out of the way, take out the troughs by their handles and empty them, charging them again by means of a toilet jug. when replaced, the whole apparatus is fit for use again; the whole of the above operation occupies but a quarter of an hour, and as there are no earthenware cells employed, there is no fear of breakage. the small amount of labor and cost of working the above apparatus will compare favorably with the production of the electric light from a dynamo-electric machine for the photographer, and when we consider that the cost of the whole of the above apparatus, consisting of a generator automatic lamp, reflector, and all the necessary appendages, is less then one-tenth of the dynamo machine, motor, shafting, etc., to produce the same result, it would seem to have a greater claim for its adoption with those who wish to employ the electric light, whether for work at night, use in the sitting room, or to assist daylight on the dark and foggy days of winter. fig. shows the arrangement of the electric lamp. a is the automatic regulator; b, the reflector; c, top extension of the reflector; d, small tissue paper screen to prevent the intense arc-rays from coming in contact with the sitter; e, stand with sliding rod. this appendage can be wheeled about with ease, as it is arranged to run upon four casters. when the generator is in use it may be placed within easy reach of the operator, so that the exposure may be made by lowering the elements in their troughs just for the requisite time, and withdrawing immediately the exposure is made; there is no need to fear any inconvenience from deleterious fumes as none are given off, so it may be used in any studio or sitting-room without any inconvenience from this source, and as far as many trials have gone, it seems to meet every requirement demanded by the photographer for the production of portraits by means of the electric light.--_photo. news._ * * * * * desruelles's electric lighter [illustration: electric lighter.] the little apparatus shown in the accompanying cut will certainly find favor with smokers, as well as with persons generally who often have need of a fire or light. it forms one of the most direct applications of dry piles of all the systems on the desruelles plan. instead of filling piles with a liquid, this plan contemplates the introduction into them of a sort of asbestos sponge saturated with an acid or any suitable solution. in this way there is obtained the advantage of having a pile which is in some sort _dry_, that may be moved, shaken, or upset without any outflow of liquid, and which will prove of special value when applied to movable apparatus, such as portable lighters, alarms on ships, railroads, etc. it is hardly necessary to say that while the introduction of this inert substance diminishes the volume of the liquid, the electro-motive force of the pile is thereby in nowise affected, but its internal resistance is increased. this, however, is of no consequence in the application under consideration. the lighter consists of a small, round, wooden box containing the pile, and surmounted by a spirit lamp. a platinum spiral opposite the wick serves for producing the light. the pile is a bichromate of potash element, in which there is substituted for the liquid a solution of bichromate identical with that used in bottle piles. the zinc is suspended from a small lever, in which it is only necessary to press slightly to bring the former in contact with the asbestos paste, when, the zinc being attached, a current is set up which traverses the spiral, heats it to redness, and lights the spirit. the pile, when once charged, may be used for several hundred lightings. when the spiral no longer becomes red hot, it is only necessary to replace the paste--an operation of extreme simplicity. when the pressure is removed from the little lever, the zinc, being raised, is no longer acted upon by the liquid with which the asbestos is saturated. mr desruelles is constructing upon the same principle a gas lighter, the pile of which is fixed at the extremity of a handle whose length varies with the height of the gas burners to be reached. these little domestic apparatus are being exhibited at the paris electrical exhibition. * * * * * solenoid underground wires in philadelphia. the _evening bulletin_ of the th october has the following: this afternoon a series of experiments were conducted at the public buildings which will be of great interest to electricians all over the country, and upon which the success of a number of underground telegraph projects in different parts of the united states depends. in all projects of this kind the problem which has given most trouble to inventors has been to overcome the induction. in other words, electric currents will leave their original conductors and pass to other conductors which may be near at hand. this interchange of currents may take place without seriously hindering ordinary telegraphy, as the indicators are not delicate enough to detect the induction. when telephones came into use, however, the induction became a great source of trouble to electricians, it often being the case that the sounds and influences from without were sufficient to drown out sounds in a telephone. to-day's experiment was conducted by mr. j.f. shorey, a well-known electrician, who exhibited dr. orazio lugo's cables for electric light, telephone, and telegraphic purposes. a large number of prominent electricians were present, including the following: general j.h. wilson, president of the n.y. and n.e. railroad, of boston; messrs. frank l pope, s.l.m barlow, george b. post, charles g. francklyn, col. j.f. casey, w.h. bradford, and selim r. grant, of new york; james gamble, general manager of the mutual union telegraph co.; t.e. cornich and w.d. sargent, of the bell telegraph co.; s.s. garwood and j.e. zeublen, of the western union, and others. the principal tests were made through the conduits on market street, laid by the national underground electric company as far as ninth street. a cable of five conductors was laid through the conduit. two of these conductors consisted of simple "circuit wires," while the other three were what is known as "solenoids." a solenoid wire is a single straight wire, connected at each end with and wound closely around by another insulated wire, this forming a complete system, the electric currents returning into themselves. electricians claim that the solenoid effectually overcomes all induction, and this afternoon experiments were made for the purpose of proving that assertion. in the telephones, connected by the ordinary wires, a constant burr and click could be heard, that sound being the induction from the wires on the poles on market street, sixty feet overhead. with the solenoid the only sound in the telephones was the voices of the persons speaking. the faintest whispers could be heard distinctly, and the ease and comfort of conversation was in marked contrast to the other telephone on the ground wires. a set of telegraph indicators was also attached to the wires in use in the cable. the sounds were transferred from one "ground wire" to the other, while the solenoids seemed to resist every influence but that directed upon them by the operators. another interesting test was made. the electric current for a hauckhousen lamp was passed through a long coil of solenoid wire. separated from this coil by a single newspaper, lay a coil of wire attached to telephones, yet not a sound could be heard in the telephones but the voices of the persons using them. the current of electricity created by a dynamo-electric machine is of necessity a violent one, and in the use of ordinary wires the induction would be so great that no other sounds could possibly be heard in the telephones. * * * * * dr. herz's telephonic systems. in an article by count du moncel, published in scientific american supplement, no , page , the author, after describing dr. herz's telephonic systems, deferred to another occasion the description of a still newer system of the same inventor, because at that time it had not been protected by patent. in the current number of _la lumière electrique_, count moncel returns to the subject to explain the principles of these new apparatus of dr. herz, and says: i will first recall the fact that dr. herz's first system was based upon the ingenious use (then new) of derivations. the microphone transmitter was placed on a derivation from the current going to the earth, taken in on leaving the pile, and the different contacts of the microphone were themselves connected directly and individually with the different elements of the pile. the telephone receiver was located at the other end of the line, and when this receiver was a condenser its armatures were, as a consequence of this arrangement, continuously and preventively polarized, thus making it capable of reproducing conversation. [illustration: dr. herz's telephonic systems.] this arrangement evidently presented its advantages; but it likewise possessed its inconveniences, one of the most important of these being the necessity of employing rather strong piles and consequently of exposing the line to those effects of charge which react in so troublesome a manner in electrical transmissions when they occur on somewhat lengthy lines. now the fact should be recalled that dr. herz's principal object was the application of the telephone to long lines, and he has been applying himself to this problem ever since. he at first thought of employing reversed currents, as in telegraphy; but how was such a result to be attained with systems based upon the use of sonorously-vibrating transmitters? he might have been able to solve the problem with the secondary currents of an induction bobbin, as messrs. gray, edison, and others had done; but then he would no longer have been benefited by those amplifications which are furnished by the variations of pressure-derivations in microphones, and this led him to endeavor to increase the effects of the induced currents themselves by prolonging their duration, or rather by combining them in such a way that they should succeed each other, two by two, in the same direction; and this is the way he solved the problem in the beginning. the fact should also be recalled that dr. herz had, from his first experiments, recognized the efficiency of those microphonic contacts that are obtained by the superposition of carbon disks or other semi-conducting substances. he has employed these under different arrangements and with very diverse groupings, but, as a general thing, it has been the horizontal arrangement which has given him the best effects. let us suppose, then, that four systems of contacts of this nature are arranged at the four corners of an ebonite plate, c c (figs. and ), at a, a¹, b, b¹, and that they are connected with each other, as shown in the cuts--that is to say, the upper disks, _e_, _f_, _g_, _h_, parallel with the sides of the plate, and the lower disks, a, a¹, b, b¹, diagonally. let us admit, further, that the plate pivots about an axis, r; that the disks are traversed by small pins fixed in the plate; and that small leaden disks rest upon the upper disks. finally, let us imagine that the plate is connected at one end, through a rod t, with a telephone diaphragm. now it will be readily understood that the vibrations produced by the diaphragm will cause the oscillation of the plate, c c, and that there will result therefrom, on the part of the disks, two effects that will succeed one another. the first will be, for the ascending vibrations, an increase of pressure effected between the disks of the left side, by reason of their force of inertia being increased by that of the lead disks; and the second will be, for the disks to the right, and, for the same reason, a reduction of pressure which will take place through resilience, at the moment of change in direction of the vibrating motions. if the current from a pile, p, traverses all these disks, through the connections that we have just mentioned, and passes through the primary helix (through the wire, i) of an induction coil h h' (fig. ), located beneath the apparatus, and if the secondary current from this bobbin corresponds, through the wire i, with a telephone line in which there is interposed a telephone or a speaking condenser, there will be set up an inverse induced current, which, being reversed as a consequence of the crosswise connections of the disks, will continue the action of the first or increase its duration, and, consequently, its force, through the telephone receiver. the results of this system are very good; but dr. herz has endeavored to simplify it still further, and with this object in view has experimented on several arrangements. for example, to obtain inversion a contact was simply placed on each side of the vibrating plate. although the movements of this latter are not, as we know, of the nature of ordinary sonorous vibrations, it was thought that they might prove to be in opposite directions on the two sides of the plate, and that one of the contacts might be compressed while the other was free. so notwithstanding the advantages of this arrangement, it was thought necessary to place the plate vertically in order to give the same regulation to the two contacts which it is essential should be identical. but it became difficult to regulate by weight; and even to succeed in regulating at all, it became necessary to employ two parallel diaphragms, vibrating in unison, and each carrying its contact, but in opposite directions. afterwards, the horizontal arrangement was again adopted; but, by a clever combination, the two principles applied by dr. herz--derivation and inversion--were united. the current is then led to a double contact, where it divides. this contact is arranged under the plate in such a way that its two points of variable resistance act in opposite directions to each other, or, in some apparatus, so that one of the points has no variation, while the other is in action. the result that occurs may be easily imagined. the system has been experimented with under different forms; in one case the derivation is simple, that is, a single one of the currents being sent into the line, while in another case it is double, each of the branches being provided with a bobbin and communicating with the receiver. in the latter case the result is remarkably good, but the apparatus is not free from a certain amount of complication, and demands, moreover, particular care in its construction, experience having shown that the induction coils must not be equal, but that they must present resistances combined according to the circuit doing duty. it should be added that researches have been continued as to the bodies proper to be employed as microphonic contact, with the result of bringing out the important fact that the number of substances that can be put to this use is almost unlimited. the contacts of the herz apparatus are now being made of conducting bodies (metals for example) reduced to powder and conglomerated by chemical means with a sort of non-conductive cement. the proportion of the elements depends upon the conductivity of the materials employed, and it alone determines the microphonic value of the compound, the nature of the elements apparently having scarcely any influence. nor has the speaking condenser been neglected. as regards this, efforts have seemingly been made toward finding a convenient arrangement and a regular mode of construction, the good working of these apparatus being absolutely dependent upon the care with which they are set up. in dr. herz's opinion, the telephone is not to remain a single apparatus, varied only as to form, but, on the contrary, must be actually modified according to the purposes for which it is designed. he thinks that a telephone operating at great distances must differ from a city apparatus, and that an instrument for transmitting song can not be absolutely the same as one for conversational purposes. so he has endeavored to create types that shall prove appropriate for these different applications. * * * * * decision of the congress of electricians on the unities of electric measures. for these measures there are adopted the fundamental unities--centimeter, gramme, second, and this system is briefly designated by the letters c., g., s. the practical units, the _ohm_ and the _volt_, will retain their present definitions; the ohm is a resistance equal to ^{ } absolute unities (c., g., s.), and the volt is an electromotive force equal to ^{ } absolute unities (c., g., s.). the practical unit of resistance (ohm) will be represented by a column of mercury of square mm. in section at the temperature of °c. an international commission will be charged with ascertaining for practice, by means of new experiments, the height of this column of mercury representing the ohm. the name _ampère_ will be given to the current produced by the electromotor force of volt in a circuit whose resistance is ohm. _coulomb_ is the quantity of electricity defined by the condition that in the current of an ampère the section of the conductor is traversed by a coulomb per second. _farad_ is the capacity defined by the condition that a coulomb in a condenser, whose capacity is a farad, establishes a difference of potential of a volt between the armatures. * * * * * secondary batteries. by j. rousse. in order to accumulate electricity for the production of light or motive power, the author has arranged secondary batteries, which differ from those of m.g. planté. at the negative pole he uses a sheet of palladium, which, during the electrolysis, absorbs more than times its volume of hydrogen. at the positive pole he uses a sheet of lead. the electrolyzed liquid is sulphuric acid at one tenth. this element is very powerful, even when of small dimensions. another secondary element which has also given good results, is formed at the negative pole of a slender plate of sheet-iron. this plate absorbs more than times its volume of hydrogen when electrolyzed in a solution of ammonium sulphate. the positive pole is formed of a plate of lead, pure or covered with a stratum of litharge, or pure oxide, or all these substances mixed. these metallic plates are immersed in a solution containing per cent. of ammonium sulphate. another arrangement is at the negative pole, sheet-iron; at the positive pole a cylinder of ferro-manganese. the electrolyzed liquid contains per cent. ammonium sulphate. * * * * * the treatment of quicksilver ores in spain. though known from remote times, the date of the first opening of the famous mines of quicksilver of almadén has not been precisely determined. almost all the writers on the subject agree that cinnabar, from spain, was already known in the times of theophrastus, three hundred years before the christian era, although there is evidence in the writings of vitruvius that they were worked at a still earlier date, spanish ore being sent to rome for the manufacture of vermilion. such ore constituted a part of the tribute which spain paid to rome emperors, and there are records of its receipt until the first century after christ. the history of almaden during the reign of the moors is so much involved in doubt that some writers deny altogether that the arabs worked the deposit; still the very name it now bears, which means "the mine," and many of the technical terms still in use, give evidence that they knew and worked that famous deposit. as for their christian conquerors, there are stray indications that they extracted mercury during the twelfth and thirteen centuries. in , almaden was given the privileges of a city, and from to the working of mines was contracted for by the wealthy family of fugger, of augsburg, germany. since then, the mine has been worked by the state, though the rothschilds have controlled the sale of the product. according to vitruvius, the works for manufacturing vermilion from spanish ore in rome were situated between the temple of flora and quirino. the ore was dried and treated in furnaces, to remove the native mercury it contained, and was then ground in iron mortars and washed. in addition, small quantities of quicksilver and vermilion were made at almaden. the ancients describe other methods, among which theophrastus speaks of using vinegar, which, however, appears from modern investigations to have been an erroneous account. nothing definite is known concerning the methods of the moors; we possess only as a proof that they produced mercury, an account of a quicksilver fountain in the marvelous palace of abderrahman iii., at medina-zahara, and the works of rasis, an arab. the moors probably extracted mercury at almaden, from the eighth to the twelfth century, by the use of furnaces called "xabecas," which latter, in the fourteenth century, were still employed by the christians, who continued them till the seventeenth century, when german workmen replaced them by "reverberatory" furnaces, which in turn were superseded in by aludel or bustamente furnaces. there is an anonymous description of the working with xabecas as practiced at almaden in , and later accounts in and . the ore was put into egg-shaped vessels with a lid, the mineral being covered over with ashes. the vessels were packed in a furnace heated with wood, about pounds being used per pound of quicksilver made. this system was also applied at the guancavelica mines, discovered in peru in , where the xabecas were abandoned in , being replaced by the furnaces invented by lope saavedra barba, which there were called "busconiles," while in spain they were named bustamente furnaces, and elsewhere aludel furnaces. they were introduced at almaden thirteen years after their first use in peru by juan alfonso de bustamente, barba and his son having been lost at sea on their way to the peninsula. in , there were at almaden, at the works at buitrones, twenty such aludel furnaces and two idria furnaces. d. luis de la escosura y morrogh, from whose work we take the above notes, has followed the historical details of the growth of almaden closely, and from his account of the method of working in we take some data: it is not an easy matter to explain the classification of the ore at almaden. _metal_ is there called the richest mineral, composed of quartz impregnated with crystalline cinnabar. _requiebro_ are middlings of medium richness, _china_ are smalls, and _vaciscos_ the finest ore. besides native mercury, which the ores of almaden contain in greater or smaller quantity, the most abundant mineral is cinnabar, which is always crystalline and is often crystallized. the ores have, besides, a small quantity of selenium and iron pyrites intimately mixed with the cinnabar. the gangue is quartz, occasionally argillaceous and bituminous. the following are assays of some of the ores made by escosura: metal. requiebro. vaciscos. china. cinnabar . . . . . . . . iron pyrites. . . . . . . . . bituminous matter . . . . . . . . gangue . . . . . . . . ---- ---- ---- ---- ---- ---- ---- ----- total . . . . . . . . quicksilver . . . . . . . . it appears to be a difficult matter to determine the average percentage of the various grades of ore. in , a commission classified and sampled a lot of tons with the following results: quantity, per cent. average of grade. no. kilos. mercury. grade. metal { . , . } { . , . } . requiebro { . , . } { . , . } . china { . , . } { . , . } . { . , . } vaciscos . , . . this general average of . per cent. of mercury is pronounced higher than the usual run of the ore, which, it is stated, does not go above to . per cent. the furnace in which the ore is treated is cylindrical, meters in diameter, and . meters high from a brick grate, supported by three arches to the arched roof. at the level of the grate is a charging orifice, and near the roof are openings into two chambers, from the bottom of which extend lines of aludels, clay vessels, open at both ends, the middle being expanded. the mouth of one fits into the back end of the one following, a channel being thus formed through which the fumes to be condensed are passed. the lines of aludels which are laid on the ground terminate in a chamber, and for half the distance between the furnaces and these chambers the ground slopes downward, while for the other it slopes upward. two furnaces are always placed side by side, and the pair have from , to , aludels. the operation is as follows: a layer of poor quartz is spread over the brick grate; this is followed by a layer of smalls, and then by a layer of still finer stuff, all of it being low grade ore. on top of this are piled two-thirds of the _china_ of the charge on which the _metal_ is put. then follows a layer of _requiebro_, another lot of _china_, and finally the _vaciscos_, shaped into balls, the whole charge amounting to about ½ tons, which is put in from an hour and a half to two hours by three men. the charging orifice is then closed, the aludels are luted, and everything made tight. the fires under the brick grate are lighted and kept going for twelve hours, during which time furnaces, charge, and condensing apparatus are heated up. during this period, the temperature in the condensing-chamber at the end of the line of aludels runs up or degrees celsius, and some mercury, evidently part of the native quicksilver, is noticed in it. the temperature of the aludels in the immediate vicinity of the furnaces is about degrees c. during this period, the consumption of fuel is four parts to every part of quicksilver produced. at its close, the fire is drawn, and the second period begins. the air entering through the brick arch is heated to from to degrees by contact with the layer of poor stuff, the cinnabar is ignited, and its sulphur oxidized, and the quicksilver vaporized and, condensing in the aludels, flows toward the depression in the central portion of the line. the temperature goes on increasing, until, twelve hours after the beginning of this period, the thermometer shows degrees c. at the first aludels. this lasts for hours, and then the third or "cooling period" begins, which takes from to hours, and during the beginning of which the temperature in the furnaces still rises. it is then opened and cooled down. a very elaborate series of observations made on the temperatures of various parts of the condensing apparatus of the almaden furnaces has shown that at the aludels nearest to them the heat increases steadily until it reaches degrees c., hours after the beginning of the operation; that in the middle of the line, at the depression, the maximum is degrees hours after starting the fires; and that at the end it does not surpass degrees. in the final condensing chamber, the temperature varied, running downward from degrees during the heating period to degrees, rising again to degrees toward the close. the loss of the quicksilver during the operation has been vary variously estimated, some stating that it is per cent. and more, while others place it at per cent. escosura, in his work, gives the details of an operation checked by a royal commission in , according to which the loss in working ore running . per cent. was only . per cent.--a loss which he considered inevitable. in , two idria furnaces were put up at almaden, but the engineers are not favorably impressed with them. the first cost is stated to be more than ten times greater than that of an aludel furnace, while the capacity is only per cent. greater. one pair of idria furnaces in five years produced , kilogrammes of quicksilver, against , kilogrammes made by eight sets of the bustamente furnaces, the cost per kilogramme of quicksilver being respectively . and . peseta. * * * * * the balloon in aeronautics. while it is undoubtedly true that the discovery of the balloon has very greatly retarded the science of aerostation, yet, in my opinion, its field of usefulness as a vehicle for pleasure excursions, for explorations, and for scientific investigations, has not been fully developed for the want of certain improvements, the nature of which it is the object of this paper to point out. the improvement of which i am about to speak relates to the regulation of the buoyancy of the balloon. this is now done by throwing out ballast or by allowing some of the gas to escape--a method which necessitates the carrying of an unwieldy amount of sand and the expenditure of an unnecessary amount of gas. from the fire balloon invented by the montgolfier brothers, in , to the superior hydrogen balloon of m.m. charles and robert, no material advancement has been made, except the employment of coal gas, first suggested by mr. green. the vast surface presented to the wind makes the balloon unmanageable in every breeze, and the aeronaut can do nothing but allow it to float along with the current. this is a difficulty which has been partly overcome, as was seen at the recent paris electrical exhibition; but no one will ever be able to guide it in a direction opposite to a current of air. the aeronaut must ever content himself in being able to float in the direction of the current or at certain angles to its course; but to do this even is a matter which has not been successfully accomplished. an inflated balloon would ascend too high unless several hundred pounds of ballast were used to weight it down. this ballast serves another purpose, it is desirable to maintain the balloon at a uniform distance above the earth's surface, and as the two per cent. daily waste of gas diminishes the buoyancy of the balloon, it must be kept from descending by throwing off a certain amount of sand. again, the heat of the sun and the action of warm air currents cause at times the volume of gas to undergo a sudden expansion, and then to prevent the balloon from running too high, the gas must be allowed to escape from the valve. the gas, under these circumstances, must also be allowed to escape in order to prevent the balloon from bursting. presently the balloon will pass through a colder current of air and sudden condensation takes place, and the balloon would sink unless more ballast were thrown off. this process continues until the aeronaut has neither ballast nor gas left. now, i suggest that a large balloon be made with the mouth closed, so that no gas can escape; and that it carry enough ballast to keep it, under an ordinary temperature, at a certain distance from the ground. a pipe must enter the mouth of the balloon, one end of which opens in its interior and the other end in a gas reservoir which lies in the "basket" or "car." as soon as the gas undergoes an expansion, and a certain amount of pressure is made in this reservoir, a valve opens and a whistle signals the moment when the force pumps must be set to work to pump the air out of the balloon into the large _number two_ reservoir, the frame work of which forms the body of the car. taking a certain amount of gas out of the balloon is equivalent to taking on more ballast, while by condensing this gas into a large reservoir, it is not allowed to escape, and when necessary can be sent back into the balloon and thus prevent the throwing off of ballast. coal gas, under a certain pressure, becomes heavier than air (or at least equally heavy), and thus the gas pumped out of the balloon will of itself serve as ballast. this invention will enable the balloonist to keep himself at a uniform distance above the earth, will prevent the carrying of so much ballast and the expensive waste of gas, and will enable him to keep afloat at least ten times as long as by the old method. i have made a model and tested the above theory. eli c. ohmart. north manchester, ind. * * * * * artists' homes. no. --mr. william emerson's house at little sutton, chiswick. [illustration] little sutton was an old house, parts of which were in existence before the time of cromwell. it is situated in a picturesque old garden, surrounded by ivy-clad walls and fine trees, one of the cedars being extraordinarily large and perfect, its huge branches covering a space of over ft. in diameter. the greater part of the old house, being uninhabitable through decay, was pulled down; the old parts are shown in black on the plan, and the new hatched. it is faced with red bricks, and red corsehill stone dressings, and covered with tiles the plan was arranged so as to preserve the old kitchen, billiard-room, morning room, and conservatory. the hall, entered from a veranda in connection with the entrance-porch, is surrounded by a dado, the height of doors; the lower panels are filled with tiles made to design by the school of art at bombay. the woodwork is painted a mottled blue color, harmonizing with the general tone of the tiles, the whole being something the color of _lapis lazuli_. the staircase is divided from the hall by three arches, through which is seen the staircase-window, representing, in stained glass, the earth, air, and water. under the central arch is the fireplace, on the hood of which will eventually be a bronze figure of orpheus, on a ground of mosaic. the floor is of marble mosaic, and round the border are the various beasts listening to the music, the trees and river, etc. above the dado, and on the wooden panels of ceiling, will be the birds, etc. the woodwork of dining-room is plain american walnut, the panels of dado being filled with dark japanese leather-paper. the panels and beams of ceiling are of stained and dull varnished fir. the drawing room woodwork, and furniture throughout, is painted a mottled greenish blue, after the same manner as the hall. the decorations of this room, when complete, are intended to illustrate chaucer's "house of fame." the chimney-piece, of alabaster, is surmounted by a caen-stone design, on a rock of glass, showing the entrance to the castle, with the various figures mentioned in the poem, carved in half-round relief, and the gateway itself also richly and quaintly carved; the rock of glass representing the ice on which the castle was supposed to be built, and on it are cut the various famous names of the world's history. in the frieze all round the room will be the figure of fame and the various groups of suppliants, and the pillars with the groups upholding the renown of ancient cities and nations, etc., executed in very low relief, and painted on a ground of blue and gold. the panels of ceilings will have conventional designs and the heavenly bodies on ground of gold and blue. the morning and other rooms have no particular scheme of decoration prepared, and are simply painted and papered in quiet tones. [illustration: artists' homes no. --little sutton, chiswick.] we publish a longitudinal section, taken through the hall and drawing-room, with part of the dining-room on the left and part of the library on the right-hand side. the beautifully-modeled plaster frieze, with the central figure of fame, is shown in the drawing-room, and illustrates chaucer's "house of fame," the whole being elaborately colored in harmony with the purposes and general tone of the room, which is in blue and gold. the hooded mantelpiece in the library is entirely in concrete, to be richly painted and gilded. the drawing, with the assistance of the description, will explain itself.--_building news._ * * * * * memorable english houses. in the year , a letter appeared in the _journal of the society of arts_ from a correspondent, who suggested that the society of arts should offer a prize or prizes for designs of memorial tablets to be affixed to houses associated with distinguished persons, and in the same year a series of suggested inscriptions was reprinted from the _builder_. the subject having been brought under the notice of the council, a committee was appointed in to consider and report how the society might promote the erection of statues or other memorials of persons eminent in arts, manufactures, and commerce, and, at the first meeting of the committee, on may , mr. george c.t. bartley submitted some memoranda on the proposal to place labels on houses in the metropolis known to have been inhabited by celebrated persons in , the first tablet was erected by the society in holles street, cavendish square, on the house where byron was born. other tablets were soon afterward put up, and the erection of these memorials has been continued to the present time. the house in leicester square, upon which a tablet in memory of hogarth has been erected, is occupied by archbishop tenison's school, for which the house was rebuilt. the original building, in which hogarth lived for several years, was long known as the "sablonière hotel." john hunter lived next door after hogarth's death. of the four worthies who were intimately connected with leicester square, viz, hunter, hogarth, newton and reynolds, and whose busts are now set up at the four corners of the inclosure, the last three have tablets erected. the house in st. martin's street, which is now occupied by the schools attached to the orange street chapel, is in much the same condition as when sir isaac newton lived in it, from to , except that the old red bricks have been covered with stucco, and an observatory on the roof has been taken away within the last few years. [illustration: newton's house, st. martin's street.] flaxman had several london residences, but the house in buckingham street, fitzroy square, is the one with which he is most intimately associated, as he lived in it during the prime of his artistic career. he went there in , when he returned from rome, and there he died in , being buried in the ground adjoining old st. pancras church and belonging to the parish of st. giles-in-the fields. the house is on the south side of the street, close by great titchfield street. [illustration: flaxman's house, buckingham street.] canning's house, on the south side of conduit street is greatly changed since the great statesman lived in it. it originally formed a wing of trinity chapel, which has been swept away within the last few years. this chapel was the successor of the chapel-on-wheels which was used at the hounslow camp in the reign of james ii., and was subsequently brought up to london. it is shown in kip's view of old burlington house as standing in the fields at the back of that house. when conduit street was built, a chapel was erected on the south side to supersede the chapel-on-wheels. the house on the west side of the chapel, where canning lived for a time, was subsequently inhabited for many years by the famous physician, dr. elliotson, f.r.s. after his death, the front was altered, and a large shop window made, as seen in the accompanying figure. it is now in the possession of mr. streeter, the jeweler. [illustration: canning's house.] dr. johnson had so many residences in london that there is some difficulty in choosing the one that is most interesting to us. the house in gough square has special claims to attention, as it was there that the great lexicographer chiefly compiled his dictionary. the garret, with its slanting roof, in which his amanuenses worked, and his own study are still to be been. johnson himself, in his "life of milton," observes, "i cannot but remark a kind of respect, perhaps unconsciously, paid to this great man by his biographers; every house in which he resided is historically mentioned, as if it were an injury to neglect naming any place that he honored by his presence." emboldened by this expression of opinion, boswell one evening, in the year , ventured to ask johnson the names of some of his residences, and he obtained the following list, which he printed in his "life of johnson:" ( ) exeter street, off catherine street, strand, ( ) greenwich; ( ) woodstock street, near hanover square; ( ) castle street, cavendish square, no. , ( ) strand; ( ) boswell court; ( ) strand again; ( ) bow street; ( ) holborn; ( ) fetter lane; ( ) holborn again, ( ) gough square; ( ) staple's inn; ( ) gray's inn; ( ) inner temple lane, no. ; ( ) johnson's court, no. ; ( ) bolt court, no. . in this last place he died in . [illustration: johnson's house.] in april, , the corporation of the city of london were asked to co-operate in this work, and to undertake the erection of suitable memorial tablets within the city boundaries. the matter was referred to the city lands committee, with which body the secretary has had several communications with respect to the localities suggested for memorials, the result being that the committee agreed to erect such tablets within the city boundaries.--_journal of the society of arts._ * * * * * domestic sugar production. the value of sugar imported into the united states, is greater than that of any other single article of commerce. in the year it appears that over one thousand eight hundred and twenty-nine million pounds of sugar were brought here from other countries, at a cost of nearly one hundred and twenty million dollars, including customs duty. moreover, the consumption of sugar, _per capita_, in this country is rapidly increasing. it was, during the ten years next preceding , only pounds on the average per annum, but, in the ten years next following, an average of pounds per annum were consumed for each person of the population of this country. this appears to be an increase of per centum in ten years. the subject of domestic cultivation of sugar bearing plants is, therefore, one of great importance to this nation, and it has accordingly engaged the attention of the u.s. commissioner of agriculture, and many experiments have been made in different parts of the country in the propagation of the various canes, roots, etc., from which sugar can be made. among sugar-bearing plants, beside the regular sugar cane, are, sorghum, sugar beet, maple, watermelon, sweet and white potato, and corn stalk. statistics show that of the , , , pounds of sugar produced in the world, about three-fourths comes from the sugar cane, and the other fourth comes mainly from the sugar beet. of the total quantity, only about one seventieth is produced in the united states, and that is mainly cane sugar from louisiana. the beet sugar has formerly been mainly produced in europe. first france, second germany, third russia, then belgium, austria, holland, sweden, and italy. the consumption of sugar in great britain is much greater _per capita_ than in the united states, about pounds, or nearly double; while in germany pounds per annum are used on an average by each person, and in russia the consumption is much less. the importance of this subject to the united states, where the consumption of sugar is increasing out of ratio to the production of sugar-bearing plants, and where agricultural independence should be realized, as we have already attained and maintained political independence, and almost independence in manufacturing industries, has called out mr. lewis s. ware, a member of the american chemical society, etc., in a pamphlet of over pages, entitled a "_study of the various sources of sugar_." from this publication it appears that the main source of sugar supply must still be _sucrose_, cane sugar, even in spite of the best efforts of the general government and of the state agricultural organizations to introduce sugar-bearing plants that will thrive in the temperate and colder latitudes of this country. with the single exception of the sugar beet, he seems to disparage all attempts to produce practical sugar from hardy plants, or those that will mature in the region of frosts in winter. even sorghum, that has for twenty years held a place in the hopes of the northern farmer, has declined so that the alleged production of half a million pounds in had became barely a twelfth of a million pounds in . in his remarks on the synopsis of one hundred and eleven experiments, made at washington, he says: "as may be noticed, thirty-five of them ( ) would yield zero. if we take the average of the hundred and eleven experiments, we find as a yield . per cent., which result cannot possibly be practically accepted. in other words, our government, notwithstanding the favorable conditions under which they were made, prove that the sorghum utilization is fallacy in every sense of the word." ... "if sorghum is to be grown for its sirup, or for fodder, it will evidently render excellent service." it seems that less than four per cent. of crystallizable sugar in the sorghum juice will not pay the cost of making sugar from it, as it will not crystallize in a reasonable time, on account of the glucose in the juice, which, with the other impurities, will prevent the ready crystallization of four or five times their own weight of sucrose. from the early history of sorghum, it appears that it was known as _sorgo_ in the sixteenth century, while twenty or thirty varieties were known under different names in egypt, arabia, and africa. some of the names are, chinese sugar cane, (sorgo), india cane, emphee or coffers' bread, paindes anges, etc. the later history of it shows that in , count montigny sent the first samples from china to europe. it had been used in the former country for thousands of years for the manufacture of red dye. the seeds were afterward sold in france for a _franc_ each. a variety came later to this country from africa, through the agency of an englishman named wray, to whom is charged the effects of the delusive experiments of trying to make crystallized sugar from its juice, which have been going on in this country for twenty years. but two varieties of sorghum now remain, known as the chinese and african types. of all the other sugar plants, none except the maple tree (besides the sugar cane and the beet) seem to have yielded sugar to pay the cost of manufacture. the maple tree has yielded a total of , , pounds in . but as an industry by itself, it appears to be unprofitable, and maple sugar must be, and generally is, sold at a higher price per pound than cane sugar; moreover, it has not the qualities that are required in a general sweetner for culinary purposes. the variety of sugar plant called amber cane is not very clearly defined, but it may be taken, from the description of the juice as to crystallizing qualities, as no better sugar producer than sorghum. it, with sorghum, is classed as a sub-variety of sugar cane, which will yield sirup and fodder, but will not crystallize under several months' time, and even then in but small percentage. on the whole it appears, as before stated, that the sugar beet is the only practicable source of sugar for the northern states, which, as experimentally shown, can be raised at a profit of forty six dollars per acre, against twenty dollars per acre, the profit of sugar making from cane in louisiana. upon this showing several beet sugar factories have been started in the united states and in canada, and their products are said to be satisfactory, and have been sold at a profit in competition with imported beet sugar. mr. ware recommends the establishment of beet sugar factories on a larger scale, to be managed by men who have had experience in this particular kind of sugar making, which seems to be a practical means of supplying ourselves with home-made sugar. it must be remembered, however, that the successful cultivation of an ample supply of beets to keep them at work is an essential prerequisite. * * * * * herald island. john muir, the geologist with the corwin arctic expedition, describes, as follows, the characteristics of herald island, hitherto known only as an inaccessible rock seen by a few venturesome whalers and explorers: after so many futile efforts had been made to reach this little ice bound island, everybody seemed wildly eager to run ashore and climb to the summit of its sheer granite cliffs. at first a party of eight jumped from the bowsprit chains and ran across the narrow belt of margin ice and madly began to climb up an excessively steep gully, which came to an end in an inaccessible slope a few hundred feet above the water. those ahead loosened and sent down a train of granite bowlders, which shot over the heads of those below in a far more dangerous manner than any of the party seemed to appreciate. fortunately nobody was hurt, and all made out to get down in safety. while this remarkable piece of mountaineering and arctic exploration was in progress, a light skin-covered boat was dragged over the ice and launched on a strip of water that stretched in front of an accessible ravine, the bed of an ancient glacier, which i felt assured would conduce by an easy grade to the summit of the island. the slope of this ravine for the first hundred feet or so was very steep, but inasmuch as it was full of firm, icy snow, it was easily ascended by cutting steps in the face of it with an ax that i had brought from the ship for the purpose. beyond this there was not the slightest difficulty in our way, the glacier having graded a fine, broad road. on the summit. kellet, who discovered this island in , and landed on it under unfavorable circumstances, describes it as an inaccessible rock. the sides are, indeed, in general, extremely sheer and precipitous all around, though skilled mountaineers would find many gullies and slopes by which they might reach the summit. i first pushed on to the head of the glacier valley, and thence along the back bone of the island to the highest point, which i found to be about twelve hundred feet above the level of the sea. this point is about a mile and a half from the northwest end, and four and a half from the northeast end, thus making the island about six miles in length. it has been cut nearly in two by the glacial action it has undergone, the width at this lowest portion being about half a mile, and the average width about two miles. the entire island is a mass of granite with the exception of a patch of metamorphic slate near the center, and no doubt owes its existence with so considerable a height to the superior resistance this granite offered to the degrading action of the northern ice sheet, traces of which are here plainly shown, as well as on the shores of siberia and alaska, and down through behring strait, southward, beyond vancouver island. traces of the subsequent partial glaciation it has been subjected to are also manifested in glacial valleys of considerable depth as compared with the size of the island. i noticed four of these, besides many marginal glacial grooves around the sides. one small remnant with feeble action still exists near the middle of the island. i also noted several scored and polished patches on the hardest and most enduring of the outswelling rock bosses. this little island, standing as it does alone out in the polar sea, is a fine glacial monument. a midnight observation. the midnight hour i spent alone on the highest summit, one of the most impressive hours of my life. the deepest silence seemed to press down on all the vast, immeasurable, virgin landscape. the sun near the horizon reddened the edges of belted cloud bars near the base of the sky, and the jagged ice bowlders crowded together over the frozen ocean stretching indefinitely northward, while more than a hundred miles of that mysterious wrangell land was seen blue in the northwest--a wavering line of hill and dale over the white and blue ice prairie and pale gray mountains beyond, well calculated to fix the eye of a mountaineer; but it was to the far north that i ever found myself turning, where the ice met the sky. i would fain have watched here all the strange night, but was compelled to remember the charge given me by the captain, to make haste and return to the ship as soon as i should find it possible, as there was ten miles of shifting, drifting ice between us and the open sea. plant life on herald island. i therefore began the return journey about one o'clock this morning, after taking the compass bearings of the principal points within sight on wrangell land, and making a hasty collection of the flowering plants on my way. i found one species of poppy, quite showy, and making considerable masses of color on the sloping uplands, three or four species of saxifrage, one silene, a draba, dwarf willow, stellaria, two golden compositæ, two sedges, one grass, and a veronica, together with a considerable number of mosses and lichens, some of them quite showy and so abundant as to form the bulk of the color over the gray granite. inhabitants of the cliffs. innumerable gulls and murres breed on the steep cliffs, the latter most abundant. they kept up a constant din of domestic notes. some of them are sitting on their eggs, others have young, and it seems astonishing that either eggs or the young can find a resting place on cliffs so severely precipitous. the nurseries formed a lively picture--the parents coming and going with food or to seek it, thousands in rows standing on narrow ledges like bottles on a grocer's shelves, the feeding of the little ones, the multitude of wings, etc. * * * * * m. bouchut's experiments with pepsine for destroying worms in the stomach and bowels have been continued with extremely promising results. even the tapeworm succumbs to the digestive action of pepsine in large doses, while the more highly organized tissues of the stomach are unaffected. * * * * * franz liszt. on the d day of october, , franz liszt, the greatest pianist of the last half century, was born at raiding, in hungary, and the entire musical world was united in celebrating his seventieth birthday, which took place this year. what can be more appropriate than to take a look at the past and recall some of the important events of liszt's so very interesting life? to recall his first appearance as a "wonder" child in his native town, the blessing and kiss he received a few years later from the immortal beethoven, his great triumphs in the paris salons and the defeat of his rival thalberg. after the appearance of the violin virtuoso paganini, he resolved to attain the highest development of his musical genius and to become so world-renowned as none has been before him, and in this was successful. he has not only maintained his standing as the greatest master of modern piano virtuosos, but has had the greatest influence on his followers and scholars, taussig, v. bulow, mr. and mme. bronsart, menter, and other younger and older pianists who have had the benefits of his instruction for a greater or less length of time, so that it can be justly claimed that the majority of our present virtuosos owe their success and fame directly or indirectly to the abilities of liszt. liszt is endowed with that great gift of treating every individual in the manner most favorable to the development of its traces of artistic ability and desires, and this accounts for his wonderful results as instructor and master. [illustration: franz liszt.] but no picture of liszt would be perfect without a _résumé_ or recapitulation of his compositions. after a most perfect transposition and preparation of numerous works of beethoven, schubert, and berlioz, and after making their compositions popular and introducing numerous valuable novelties in the art of playing piano, he produced his "symphonische dichtungen" (symphonic poems). these highly dramatic compositions, in which he follows berlioz and often produces the most astonishing effects of sounds, however, did not find entire approbation with the public, and did not succeed in popularizing themselves. but that fact can be recorded in his favor that every programme containing liszt's "dante," or faust symphony, or "mazeppa," receives more than ordinary attention from the public. the same is the case with his solo songs with piano accompaniment, in which, however, ingenious details often tend to drown the original melody. of his quartets, some have become highly popular with singing societies and form part of their _repertoire_. the crowning point of liszt's compositions is to be found in sacred music, for instance in his mass known as the "grauer messe," composed for the dedication of the cathedral at grau, in hungary; the crowning mass, and his two oratorios, "die heilige elisabeth" and "christus." but even they caused a decided difference of opinion; and if some knew no bounds for their enthusiasm, others could not find an end for their condemnation. such works should not be treated too lightly, and a thorough and impartial examination will show that a place of honor must be accorded to them in the history of music. since the "heilige elisabeth" has been produced in several cities of germany it has been viewed more favorably and disarmed many of the opponents. but liszt also belongs to the literary fraternity, and his works, published by breitkopf & hartel, contain some of the best ever written in regard to art and artists. they were mostly written in elegant french originally, and relate to the social position of artists and the state of the art of music in certain cities or even an entire country. a part of his works is devoted to the music of gypsies, and to a true and honest history of the life of his friend chopin. then again we find him preparing the path to the hearts of the public for berlioz, schumann, wagner, robert franz, and meyerbeer. liszt has certainly collected enormous sums of money in his successful career, but as fast as he reaps his earnings he gives them to those needing assistance, and it is almost entirely to him that the inhabitants of bonn, on the rhine, owe their beautiful beethoven monument, and during the last years liszt has been untiring in giving concerts and collecting money for a monument for the greatest of the great, johann sebastian bach. liszt is an artist in every sense of the word, and we should all wish that he will remain among us for many years more. * * * * * m. garnier's new methods of photoengraving. by major j. waterhouse, b.sc. in one of the upper rooms of the electrical exhibition in paris, there is an interesting collection of plates and proofs produced by various methods of photo-engraving, invented by m. henri garnier, whose name is so well known in connection with these processes, and whose beautiful plate of the chateau of maintenon gained for him a gold medal at the paris international exhibition of . some interesting details of these processes are given in an extract from a report on them by m. davanne to the société d'encouragement pour l'industrie nationale, read at its sitting on the d july last, of which copies are distributed gratis in the exhibition. the report opens with a brief allusion to m. garnier's continuous labors in permanent photographic printing, commencing with the ingenious mercury process worked out in conjunction with m. salmon, and published in , in which a print which has been exposed to the fumes of iodine is laid down on a plate of polished brass, so that the iodine, absorbed by the printed lines, slightly attacks the brass; mercury being then rubbed over the brass, forms an amalgam with the iodized parts. if a roller charged with printing ink be now passed over the plate, the ink will only be taken on the pure brass, and not on the iodized parts. the plate is next bitten with acid nitrate of silver, and may then be treated in various ways, so as to form either a printing-block or an engraved plate. the process never came to any practical use, but led m. garnier to the invention of the very valuable and largely used process of acierage or steel-facing, by which the surface of engraved copper-plates is so hardened and protected by a thin coating of iron that instead of only a few hundred impressions, many thousands can be printed from a plate without the slightest deterioration. the next invention noticed is the citrate of iron process of m.m. salmon and garnier, in which a paper, coated with a sirupy solution of citrate of iron, is exposed to light under a positive print for a period varying from eight to ten minutes in the sun, to half or three-quarters of an hour in the shade. in the parts where the light has acted the paper becomes non-hygroscopic in proportion to the intensity of the action of the light upon it. the paper being left for a short time to absorb moisture from the air, is dusted over with lamp-black, which, attaching itself to the unexposed parts, reproduces an exact image of the original drawing. m. garnier has since greatly modified this method of obtaining an image by dusting, and applied it to various processes of photo-engraving. the report then proceeds to give the following details of a process of photo-engraving, which was exhibited before the society by m. garnier in march last: photogravure. in photo-engraving a distinction must always be made between the reproduction of drawings in line and those with shaded tints. a.--_photo-engraving of line-work._--a plate of copper is prepared by covering it, either by flowing or with a roller, with a very thin coating of a solution of: sugar grammes. bichromate of ammonia gramme. water grammes. this coating is equalized and quickly dried by means of an arrangement which keeps it in rotation over a warm plate. as soon as the plate is dry, a positive cliché of the drawing to be reproduced is laid upon it, and the whole exposed to the sun for a minute, or to the electric light for three minutes. the reaction produced is the same as with the citrate of iron, but much quicker; the exposed parts are no longer hygroscopic, but in the parts protected by the lines of the drawing the sensitive coating has retained its stickiness, and will hold any powder that may be passed over it, thus producing a very clear image of the drawing. the coating being excessively thin, the little moisture it holds and the powder applied suffice to break its continuity, especially if the powder be slightly alkaline. if the rest of the surface were sufficiently resisting, the plate might be bitten at once; but light alone is not enough to produce complete impermeability: the action of heat must be combined with it. the plate is, therefore, placed on a grating, with wide openings, a large flame is applied underneath, and it is heated till the borders where the copper is bare show iridescent colors. the sugary coating thus becomes very hard in the exposed parts, but under the powder it is broken, porous, and permeable to acids. the surface is then covered with the biting fluid, which is a solution of perchloride of iron at ° baumé, and after few minutes' contact the plate is engraved. it only remains to clear off the bichromated sugary coating which forms the reserve, and which, being hardened by the heat, resists ordinary washing. it is removed perfectly by rubbing the surface with a hard brush and warm potash lye; the plate is then ready for printing. sometimes it may be necessary to give several successive bitings, or to use a resinous grain; in such cases the various methods of the engraver's art are employed. b.--_photo engraving for half-tones._--to reproduce by engraving the image of any object, a portrait, or a landscape, the gradation of tint is obtained by repeating three times in the following manner the operation a, just described: the copper plate being prepared as before, it is exposed to the light under a positive, and given a long exposure, say four minutes, in the electric light. the sugary coating hardens under the whites and the lighter shades--it only remains tacky under the blacks. the positive cliché is removed, the plate powdered, and bitten; the blacks alone come out. the plate is cleaned, then coated again with the sugary preparation, and exposed a second time under the positive, care being taken to preserve an accurate register, which may easily be done. the second exposure is not so long as the first--say two minutes, and gives the image of the middle tints and blacks. the plate is powdered and bitten as before, bringing out the middle tints, and, at the same time, giving greater depth to the shadows. in the third operation, the plate is exposed still less to the light--say one minute. the high-lights alone harden; the light shades, middle tints, and the shadows remain permeable. after powdering and biting, the plate is finished. when necessary, after each operation, a resinous grain may be applied in the manner usual with engravers. it is important to note that m. garnier affirms that in both cases the engravings are untouched, and that this is one of the essential characteristics of his process. c.--_engraving in relief for letter-press._--in the case of drawings in lines to be made into printing-blocks for letter-press printing, the operation is conducted in its first phase absolutely in the same manner as the foregoing, only, after exposure, instead of producing the image with a slightly alkaline powder, powdered bitumen is used, and the plate is slightly warmed, so that the powder may slightly fuse and adhere to the metal, but not enough to make the bichromated sugar become insoluble. the plate is then washed with water, and all the sugary coating removed, leaving the surface of the copper bare, except where it is protected by the bitumen forming the image. the plate is then bitten with perchloride of iron, which gives a first biting, leaving all the lines in relief. further depth is obtained by alternate inkings and bitings, as in the gillotype method. the above processes are very interesting, the use of the sugary coating, the hardening it by heat, and the triple exposure and biting are new--at any rate, have not, so far as i know, been published before. the report then goes on to describe a further application of the same principle to obtaining photographic images recently invented by m. garnier, and called by him atmography. photographic printing by vapor--atmography. this process consists in tracing or transferring by means of vapors or fumes an image of any object from one surface to another, whence the name of atmography it is proposed to give it. the operations are as follows: when an image formed of a powdery substance has been obtained either by dusting (as described above), or by filling an engraved plate with the powder, the plate bearing the image is exposed to a vapor, which has no effect upon it. the powder alone absorbs the vapor, and if the plate be then applied to a surface coated with some substance capable of being acted upon by the vapor, an image is obtained upon this second surface. for example, the lines of an engraved copper-plate are filled with powdered albumen. on the other hand, a few drops of hydrofluoric acid are spread over a wooden board, and the powdered engraving is exposed for ten to fifteen seconds to the fumes disengaged by holding it about a quarter-of-an-inch above the board. the acid is absorbed by the powdered albumen without attacking the copper. if this plate be now placed in close contact with any surface (metal, paper, or glass) which has been covered with a coating of sugar and borax, and dried immediately, a deliquescent fluoborate of soda is produced under the action of the acid vapors, the sugar becomes tacky, and, by brushing a powder over this surface, the image appears immediately. in m. davanne's opinion this new invention of m. garnier's seems likely to have a useful and extended application. the image may be made with powder of any desired color. if it is on glass, it may be transferred to paper or other support by means of collodion or gelatine. by employing enamel powders, this process gives a new method of producing vitrified images. it may also be used as a simple method of reproducing engravings under certain circumstances; copies of diagrams, however intricate, could easily be produced on glass by it, and used for the illustration of lectures by means of the magic lantern.--_photo. news._ * * * * * dangers of pyrogallic acid. by dr. t.l. phipson. some time ago, dr. napias, of paris, who devotes much of his time to matters connected with hygiene, took up the subject of the hygiene of the photographer, and published in the _moniteur de la photographie_ a series of papers which were afterward translated into english and published by messrs. piper & carter, of london. in them the worthy author has considered the action on the economy of the various poisonous substances which pass daily through the hands of our readers, and the best means of counteracting their influence. since then--in fact, quite recently--attention has been called in the medical journals to certain properties of pyrogallic acid which were perfectly unknown, and show that this substance, even when applied externally, may act as a violent poison causing death by its great affinity for oxygen. i published a short note upon the subject in the _journal of medicine_, etc., for april last, and it may perhaps be useful to reproduce the facts here. physicians who were unacquainted with this energetic deoxidizing property of pyrogallic acid have proposed it as a substitute for chrysophanic acid in the treatment of skin diseases; but dr. neisser has made known a case of poisoning by an ointment of pyrogallic acid, which at once shows that considerable danger attends its use for this purpose. a man of strong constitution was admitted into one of the wards of the breslau hospital to be treated for general psoriasis. he appears to have been submitted to a kind of experimental treatment in order to test the curative properties of pyrogallic acid as compared with chrysarobine. he was treated by friction with chrysarobine (in the form of a pomade of alcoholic extract of rhubarb, containing one-twentieth) on the one-half of the body, while the other half was treated in the same manner by a pomade containing ten per cent. of pyrogallic acid. six hours after the application the patient had violent shivering with vomiting and intense collapsus. death occurred on the fourth day. experiments were at once undertaken on rabbits, and proved that this catastrophe was due entirely to the pyrogallic acid pomade, and that the chrysarobine was innocuous. in some instances the rabbit died within two hours. it was also found that in the case of the patient in the breslau hospital the pyrogallic acid had acted by its extreme avidity for oxygen when in contact with alkaline fluids. the blood had been affected, and the red corpuscles were destroyed and turned brown. very little urine was voided, but it presented a most extraordinary character, being dark brown and very thick; it contained no blood corpuscles, but a considerable amount of hæmoglobine (the coloring matter of the corpuscles), which was recognized by the absorption bands it gave in the spectroscope. the kidneys were uniformly bluish black. the blood had a dirty brownish red tint, and contained an abundance of _detritus_ of red corpuscles. this case points out once more that photographers cannot use too much prudence in dealing with chemical products which are in daily use by them, and the noxious properties of which, they are apt to forget.--_photo news._ * * * * * a catalogue, containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . , stitched in paper, or $ . , bound in stiff covers. combined rates--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, park row, new york, n.y. * * * * * patents. in connection with the scientific american, messrs. munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best-terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats, trade marks, their costs, and how procured, with hints for procuring advances on inventions. address munn & co., park row, new york. branch office, cor. f and th sts., washington, d.c. [illustration: a good patent, properly handled, is a stepping stone to success and fortune.] practical pointers _for_ patentees containing valuable information and advice on the sale of patents an elucidation of the best methods employed by the most successful inventors in handling their inventions _by_ f. a. cresee, m.e. revised and corrected, with new forms and tables of population of the united states in accordance with the census [illustration] munn & co., inc. scientific american office broadway new york _copyright, , by the_ potomac publishing company _copyright, , by_ munn & company _copyright, , by_ munn & company _copyright, , by_ munn & co., inc. new york macgowan & slipper beekman street preface the original conception and working out of an invention is usually a labor of love on the part of the inventor: having perfected his invention in every detail, he finds able and skilled counsel waiting to prepare and prosecute his application for patent before the patent office examiner. when the patent is allowed or issued, the patentee's real work begins--that of turning the patent into money. this is the business end of the inventor's work, which is generally to his interest financially to undertake himself, or to have under his immediate supervision. the object of this little work, based upon the experience and observation of the author and other successful inventors, is to give the patentee such information and advice as will enable him to proceed more intelligently, on the most successful and economical basis, to realize from his invention. the american government issues annually over thirty-five thousand patents, a large number of which are offered for sale by their respective patentees, who in many cases have no definite lines to pursue in negotiating their patents; many realizing little or nothing from their inventions through careless or bad management, while others, through incompetency, drift into the hands of unscrupulous patent-selling agents only to be swindled. the numerous inquiries from patentees seeking practical, reliable, and up-to-date information as to the best and most successful methods of realizing from the product of their ingenuity, has led the author, after due deliberation, to prepare and present this work to the american inventor, with a view of supplying a long-felt want, with the hope that it will save them many expensive experiments in handling their patents, and advance them on the road to success. it has been the endeavor of the writer to cover briefly every subject that is usually encountered by patentees in disposing of their patents, not only in the matter of selling, but also in the equally important and perplexing questions of arriving at the value of patents, legal forms, statistics, etc., etc. realizing that the work may be deficient in many respects, the hope that it will prove instructive, and the belief that it contains many practical pointers for patentees is still entertained by the author. contents chapter i. demand for inventions of merit. page monopoly in patents--industrial progress based upon the patent system - chapter ii. income from inventions. independence through successful invention--unprofitable patents--money in patents--business capacity of the inventor--inventions as a poor man's opportunity to advance - chapter iii. securing capital. danger in an undivided interest--a better plan--form of agreement--perfecting inventions--exhibit of inventions--to avoid being "squeezed"--value of record of invention--newspaper notoriety - chapter iv. how to arrive at the value of a patent. pecuniary value--commercial value--basis for estimation--general rules for valuation--how rating for royalty is figured--stock in stock companies--prices for territorial rights--valuation tables - chapter v. how to conduct the sale of patents. patent-selling agencies--the best selling agent--in case the patentee cannot undertake the selling--methods of selling patents--about advertising--how to write an advertisement--correspondence as a means of bringing patents before interested parties--how to correspond with manufacturers--circulars--illustrations--about getting up circulars--copies of patents, how to secure--uses of printed copies--first impressions all--important--value of models--working drawings - chapter vi. how to conduct the sale of patents.--_continued_. value of personal influence--personal solicitation advisable--selling outright--assigning an undivided interest--dividing a patent into different classes of rights--granting licenses--placing upon royalty--manufacturing and forming companies--to organize stock companies--trading as a last resort - chapter vii. canadian patents. about canadian patents--selling canadian patents-- population of canadian cities - chapter viii. decisions and notes. assignments--territorial grants--licenses--patent title--rules of practice--assignments--assignees-- grantees--mortgages--licensees--must be recorded-- conditional assignments--state laws on selling patents - chapter ix. the transfer of patent rights. assignee, grantee, and licensee defined--the language of law--assignment of entire interest in letters patent--assignment of an undivided interest--grant of a territorial interest--license; shop right--license; non-exclusive, with royalty--license; exclusive, with royalty - chapter x. tables and statistics. map of the united states--official census of the united states by counties for --population of cities of the united states--number, acreage and value of farms, by states--table of occupations - index - practical pointers _for_ patentees chapter i demand for inventions of merit that there is a demand for inventions of merit which can be readily disposed of at a reasonable profit to the inventor, there can be no doubt. there perhaps never was a time in the history of our country when the demand for meritorious inventions was so great as the present. the conveniences of mankind, in all his varied vocations and callings, require continual changes and improvements in the apparatuses and implements used in order to save time, labor, and expense, and to keep pace with the never-ceasing progress of civilization. at no time in the past has there been so deep an interest manifested by the public generally in the inventions of our bright-minded men and women, and at no time has capital been more readily interested and ready to invest in any practical improvement which can offer a fair chance of monopoly under the patent laws. business men, capitalists, and manufacturers are ever on the alert for new and desirable inventions, which will supersede in utility those which are already on the market. by purchasing such inventions, they secure novelties which will not only enable them to avoid the keen competition and to a great extent monopolize the trade in their own respective lines of business, but also to make sales more easily, and thus make their business more profitable. [sidenote: monopoly in patents.] every well-informed person knows that a monopoly is the desideratum of business men. the monopoly or protection of an industry afforded by the patent laws is, perhaps, the one monopoly that directly benefits the world. were it not for the protection and monopoly offered inventors by governments, for a certain number of years, to disclose their inventions, inventors would simply keep them secret, or if used at all, would do so only in such a manner as would prevent the world at large from learning of or utilizing them, thus debarring the public as a whole from their benefits. this monopoly in patents has had much to do with the material progress of the world during the century just ended. anyone having a monopoly of a good trade article is assured of a fortune. if capitalists and manufacturers can secure the control of any new invention of merit for their sole use and purposes, which can be manufactured and sold more cheaply than those now on the market, and which will perform its work in a quicker and better manner than the devices now in use, they will be only too willing to pay patentees handsomely for patents covering such inventions. there are numerous staple articles of commerce whose manufacture is open to all, and which every mercantile house in the country is handling at a profit, notwithstanding the great number engaged in their manufacture and sale in every section of the country. now, if there can be supplied some better or cheaper article in any line of industry, the firm or person who secures the monopoly of its manufacture and sale, simply controls the market, and human endurance and energy are the only limits to the degree of profits such a firm or person can secure from the manufacture and sale of such an article, if adequately protected by a valid patent. [sidenote: industrial progress based on the patent system.] in an official report the commissioner of patents clearly sets forth that from six to seven eighths of the entire manufacturing capital of the united states is either directly or indirectly based upon patents. this vast amount of money, upward of six thousand millions of dollars, continually employing great armies of people, in industries based upon patents of every class, supplies the country with improved articles of every description. it has been well said that, "patents and trade go hand in hand." the largest and most opulent manufacturers in the country will be found to be the heaviest owners of patents, developers of inventions, and patrons of the patent office. while all inventions are not telegraphs, telephones, sewing-machines, or electric lights; nor can all business houses be westinghouses, hoes, mccormicks, bells, or edisons, yet all over this country, and others as well, there are springing up a great number of moderately large growing firms who, ever on the alert for success, devise or secure control of some valuable patent, by which they can successfully invade and control to a certain extent particular lines of industry. nearly every leading factory in the world owes its commencement and success to the prestige and protection afforded by the possession of a good and valid patent. chapter ii income from inventions it has been aptly said that the products of all the gold, silver, and diamond mines in the world would not equal in value the annual income of american inventors. it has been carefully estimated that there are at least fifty patents in the united states which yield over $ , , annually, some that yield over one-half million, from to which bring from $ , to $ , , and between , and , that bring over $ , annuities. besides these, there are thousands upon thousands of patents which yield yearly more profit to their fortunate possessors than could be accumulated in a lifetime by a wage-earner. [sidenote: independence through successful invention.] there are thousands of patents sold outright every year by the patentees of the united states for thousands of dollars; and, to the already long list of successful inventors, each year adds many more, who have become independent through the proper handling of the product of their ingenuity. indeed there can hardly be conceived a quicker way for the average person to attain independence and wealth than by inventing something of real worth and merit that can be quickly turned into money. the inventive field is large, and each invention opens up a new field for improvements, and it is the "improver," without question, that reaps the greatest benefit from any invention. owing to the ever forward progress of civilization, there is no limit to the possible improvements in the sciences, arts, and manufactures. [sidenote: unprofitable patents.] it must, however, be borne in mind that all patents are not remunerative, neither are all gold mines productive of fortunes, and one may lose money in patents as well as in any other business. there are thousands of patents, many having merit no doubt, which have never been sufficiently brought before the public to test their merits, effect their sale, or manufacture; this in many instances is owing to incompetency, or bad management on the part of the patentee or his agents. there are thousands of other patents that do not prove remunerative because they do not supply a real want, while still others are such slight improvements upon existing inventions that they necessitate such narrow claims, which render the patent of little or no value. one has only to look over the weekly issue of patents to see many of the last class. as before stated, while there are many thousands of patents that do not pay--and many no doubt cause their owners disaster, as is the case in any other business or investment; on the other hand, the far greater proportion of patents granted are productive of handsome profits, if properly managed. [sidenote: money in patents.] that the majority of patents taken out prove lucrative is evident from the fact that upward of seventy thousand applications for patents and designs are filed each year in the united states patent office, and approximately eight hundred are granted and issued each week. probably about one-fifth of these patentees obtain their patents with a definite view of manufacturing their inventions, and the remainder obtain theirs with a view of realizing from the sale of the rights to manufacture. it may be said, as a general thing, there is more money in small inventions than in larger ones, from the fact that they can be easily manufactured anywhere with but little outlay of capital; they usually fill a general need, and the profit derived from their manufacture is large, besides the patent is more readily disposed of; while with larger inventions it requires more money and ability in handling the patent, and the invention must be unusually promising to justify the erection of a plant costing thousands of dollars for its manufacture. however, when large and complicated inventions do pay, they usually pay well. [sidenote: business capacity of the inventor.] it must be remembered that the actual cash value of a patent is not in the patent itself, but in the sale or use of the monopoly it affords, and the amount realized from any invention frequently depends upon the business capacity of the inventor or his agents. owing to his business ability, one person may make a fortune out of an unpromising improvement, while another, through bad or careless management, will realize little or nothing from a brilliant invention. speaking along this line in an official report the chief examiner of the patent office says: "a patent, if it is worth anything, when properly managed, is worth and can easily be sold for from $ , to $ , . these remarks only apply to patents of ordinary or minor value. they do not include such as the telegraph, the planing machine, and the rubber patents, which are worth millions each. a few cases of the first kind will better illustrate my meaning: "a man obtained a patent for a slight improvement in straw cutters, took a model of his invention through the western states, and after a tour of eight months returned with $ , in cash or its equivalent. "another inventor in about fifteen months made sales that brought him $ , , his invention being a machine to thrash and clean grain. a third obtained a patent for a printing ink, and refused $ , , and finally sold it for about $ , . "these are ordinary cases of minor inventions embracing no very considerable inventive powers and of which hundreds go out from the patent office every year. experience shows that the most profitable patents are those which contain very little real invention, and are to a superficial observer of little value." under the writer's personal observation has come many instances where inventors have secured patents on improvements which to a casual observer would appear insignificant, yet through shrewd management they have been made to yield princely incomes. among these one case worthy of note is that of a young man in pennsylvania who secured a patent on a toy game which any person could have thought of, but few would have considered worth protecting by letters patent. he was offered $ , for the patent by one manufacturer at the outset which he refused, and afterward he placed it on royalty with quite a number of large manufacturers throughout the country. he receives but one cent on each one manufactured, yet his income averages over $ , a year. another borrowed part of the money with which to obtain a patent on a railway tie plate, which was bought by a corporation for $ , , after having manufactured it for two years on royalty. and many others, who have realized from one to five thousand dollars on such slight improvements on which few would have thought worth applying for a patent. patentees who would realize any considerable amount from their patents must not sit down and expect the other fellow to make money out of their inventions for them. [sidenote: inventions as a poor man's opportunity to advance.] invention is sometimes called the "genius of the poor," and it is a singular fact that there are a greater number of inventions made by men and women of limited means than by those whose wealth, education, and other advantages would seem to have especially fitted them for success in a field dominated so completely by "brains." this may be explained in a measure by the fact that people of moderate means are brought into closer contact with the arts and manufactures, and are thus the first to discover and improve their defects. a self-made millionaire, recently speaking to the writer about patents, said: "i know of no business or vocation requiring so small amount of capital, and yielding such immense profits as that of invention. certainly no person of inventive genius can employ his time and ingenuity to better or more profitable advantage than to invent something that is really needed. many poor men, through the art of invention, have risen from poverty to reputation, fame, and honor, and taken high places among noted men of all times. our moneyed kings may have enriched themselves by stock jobbing, but this precarious procedure requires large capital, and the few enormous fortunes accumulated are merely the monuments marking the graves of thousands of foolhardy unfortunates caught in the vortex of speculation." chapter iii securing capital it is a curious but well demonstrated fact that people who have inventive genius often lack the means to carry out their ideas. an inventor who has ample means can secure his patent and proceed to turn it into money without the necessity of being compelled to solicit financial aid from anyone. this, unfortunately, is not generally the case with inventors; indeed, many are often barely able to stand the expense incident to taking out the patent. patentees laboring under this disadvantage are frequently tempted to part with a small interest in their patents for the sake of securing sufficient funds to carry on the promotion of their inventions and sale of the patent; and in doing this the inexperienced patentee is apt to make the fatal mistake of assigning to another an undivided interest in his invention. [sidenote: danger in an undivided interest.] such an assignment may appear well enough on the face of it, and many patentees have been misled, supposing that under the assignment the proceeds from the patent should be divided _pro rata_, according to the several interests. this, however, is not the case in such assignments, and joint-ownership of a patent, or interest therein, does not of itself, without an express agreement to that effect, make the parties partners. they are merely tenants in common, each having the right to separately make, use, or sell the invention so assigned without liability to account to their co-owners for any part of the profits derived from the invention through their own efforts. in an assignment of an undivided interest, the assignee is afforded an opportunity of manufacturing, using, and selling to others to be used the article covered by the patent; also, to grant territorial grants, such rights being unlimited by the terms of the assignment, and it is actually of little consequence how small an interest is thus conveyed, the assignee can proceed with the patent in much the same way as if he were the sole owner; therefore, whenever it is intended that the relation of co-partnership shall exist between the patentee and the assignee of an undivided interest, and that the profits arising from the invention shall be equitable, for their joint benefit, there must be an express agreement between them to that effect, otherwise the assignee will have a decided advantage over the inventor, if he is inclined to be dishonorable, and there are numerous cases on record where patentees have virtually lost their patents by such assignments. patentees should especially guard against strangers who offer to purchase an undivided interest in their patents. [sidenote: a better plan.] a better procedure to secure means necessary for the development, introduction, and sale of an invention is to borrow the money from a friend contingent on the sale of the patent, sell a state or county right, or enter into a contract with a party willing to furnish the means for a certain proportion of the proceeds derived from the invention. generally speaking, it will not be hard to find a party willing to advance sufficient means to promote an invention which is protected by a patent for a certain percentage of the net receipts arising from its manufacture, sale, or territorial grants, and the patentee will probably find a person among his own acquaintances who will not only be glad to furnish the means necessary, but also be of value to the patentee in realizing from his invention. in any case, whatever is agreed upon should be put in the form of a contract, or an agreement, couched in such terms as will leave no doubt as to the understanding between the parties. the following form secures both parties, and will be suggestive of others: [sidenote: form of agreement.] _whereas_ i, richard doe, of philadelphia, county of philadelphia, and state of pennsylvania, have invented certain new and useful improvements in telegraph keys, for which i have obtained letters patent of the united states, bearing date january , , and number , , and whereas john roe, of camden, county of camden, and state of new jersey, is desirous of obtaining an interest in the net profits arising from the sale or working of the said invention covered by the said letters patent. now, therefore, this indenture witnesseth, that for and in consideration of one dollar by each of the parties hereto paid to the other, the receipt of which is hereby acknowledged, it is stipulated and agreed as follows: first, that the said john roe shall pay all moneys necessary to the construction of a suitable model to represent the said invention; that he shall pay all necessary expense in advertising and bringing said invention before interested parties (and such other clauses as may be deemed necessary and agreed upon, such as the expense of constructing a working model, or carrying out a process, etc.); that he shall make diligent effort to promote the said invention, its manufacture, and sale. second, that the said richard doe, sole owner of said invention and letters patent, in consideration of the payment of the moneys above mentioned, agrees to pay the said john roe twenty-five per cent. (or other amount agreed upon) of all the net receipts in any manner arising from the sale or working of the said letters patent, during the term for which said patent is granted. witness our hands and seals this tenth day of january, a.d. . richard doe, john roe. in the presence of: john smith, thos. jones. [sidenote: perfecting inventions.] should an inventor defer the filing of his application until his invention is fully developed as regards the detail construction and arrangement of the parts? the best opinion seems to be in favor of the prompt filing of the application. the final form of the details can best be determined by the manufacturer and expert machinists and designers, who appreciate the matter of economical manufacture, which is quite as essential as the efficiency of the device or machine. clearly, therefore, the inventor cannot decide as to all the details; why then should he delay his application? the safest course for an inventor is to file his application for a patent as soon as his invention is complete in its principal features, so as to conform to the requirement of the patent law that an invention be sufficiently complete to be theoretically operative. the mechanical details are rarely of great importance as far as the patentable features of the invention are concerned. still, it is well to give the attorney full particulars of whatever details the inventor has in mind. [sidenote: exhibit of the invention.] under the security thus afforded for the main features involved in his idea, the inventor can proceed more deliberately in perfecting and improving his invention, and can then file an additional application if necessary, to secure special protection on particular improvements or the improved invention as a whole. the early filing of an application may turn out to be important in securing to the inventor his right of priority. when the inventor comes to exhibit his invention, with the idea of bringing it to the attention of the public in general, there is no question that he should then have his invention in the best form he can, and in as attractive shape as possible. [sidenote: to avoid being "squeezed."] the patentee who proposes to realize from his invention should never let it be known that he is in want; of course, in some cases he cannot help himself, but he should endeavor to obtain the necessary assistance from his acquaintances, and under no circumstances let those with whom he is trying to deal get an insight into his financial condition, as capitalists and others will very often take the advantage of an inventor when known to be in straitened circumstances, and the patentee probably would not realize as much from his patent as he otherwise could. therefore, it is advisable in all cases for the patentee to manifest no impatience, remain silent as to his financial condition, and strive to impress those with whom he is dealing that he is in no condition to be "squeezed." [sidenote: value of record of invention.] inventors, while working on a complicated machine, should not overlook the value and importance of keeping a record of the progress of the development, illustrating it with sketches, signing and dating them with each new addition, and, when practical, having it witnessed by one or more persons. this plan is preferred by many inventors to filing a caveat. such a record will be found very valuable in case of an infringement, as it enables the inventor to ascertain the various steps of his invention, and is a sort of evidence that cannot be impeached. such a record of a complicated invention, when the inventor has put much time and study upon the subject in perfecting it, will also be found valuable in effecting sales, and in fixing the price of the patent. [sidenote: prejudice against patents.] it cannot be denied that at the present time there seems to be in many sections of the country a strong prejudice against patents, which sometimes makes it difficult to get people sufficiently interested to take hold of any patent; especially is this true when the patentee endeavors to sell his patent piecemeal; that is, by county, township, shop, or farm rights. no matter how important or valuable the invention may be, there seems to be a disposition on the part of the public to look upon such rights as a fraud, and to be very cautious how they invest in them. the public is not wholly to blame for this, as in recent years there has been a class of men who have canvassed the country with patent rights, not caring what representations they made so long as they were able to effect a sale; consequently, many people have been lured into purchasing patent rights for a small territory which in many instances were worthless or not as represented, causing them to be more or less skeptical of all patents, as well as to bring this manner of selling patents generally into ill repute. with manufacturers and capitalists, this prejudice does not exist to any great extent, as with them the patent rests solely upon its own merits. [sidenote: newspaper notoriety.] many inventors overlook the importance of interesting newspaper men in their inventions. this is a matter of great consequence to the inventor in exploiting his invention, and should be given some attention. newspapers desire items of interest of every description, and readers are usually interested in brief accounts of any new invention possessing novelty or merit; so that when the inventor once gets his invention into the newspapers it is generally copied by other papers, with the result that the invention gets a large amount of free advertising and publicity. these items frequently attract the attention of capitalists, manufacturers, and others, and at once put the invention in a favorable position before the public as could be done possibly in no other way--certainly in no cheaper way. many of the trade journals and other periodicals are also open to receive technical descriptions of inventions of merit concerning industrial improvements. such articles should be written in good form, containing not over five hundred or a thousand words, and if admitted to this class of publications will be of the utmost value and importance in creating favorable public opinion, and in advancing the inventor's interests. with hardly an exception, if an invention strikes editors favorably and is adjudged to be of sufficient interest to form an article of news in newspapers, or of sufficient merit to warrant a description in the trade papers, it is pretty certain to prove a success and bring the inventor large returns. if the invention is of such a character as to strike newspaper men unfavorably, the inventor can resort to the advertisement columns; using the large daily papers, or such publications which in some way relate to the industry to which the patent appertains, and such as have the largest circulation among the class of people it is desired to reach. see about advertising on page . chapter iv how to arrive at the value of a patent most inventors are not concerned so much about the fame or honor their inventions will bring them, or how much their inventions will advance civilization, or build up a nation, or administer to the conveniences and pleasures of mankind generally, as they are about how much it will net them in dollars and cents; but the patentee should not lose sight of the fact that the profits are in the exact proportion to the actual usefulness of the invention, and its general adaptability. it is immaterial whether the inventor himself intends to deal with the public, or to deal with a man or set of men who are afterward to deal with the public, the conditions are the same, and the profits must ultimately come from the sale of the manufactured article. [sidenote: pecuniary value.] it may seem superfluous to say that mere letters patent aside from an invention is of no value, though many inventors are under the erroneous impression that if an invention possesses patentability, it must also necessarily have pecuniary value. to be of any pecuniary value whatever, the invention must cover something for which there is a demand, or for which there can be a demand created, for it cannot be disputed, that if an invention will not bring in money by manufacturing it, it is, in a financial sense, worthless; and the patent thereon is therefore worth some seventy or eighty dollars less than nothing. [sidenote: commercial value.] an invention, to have commercial value, as previously stated, must cover something for which there is a demand, or for which there can be a demand created. it may be an entirely new device, or it may be an improvement upon an existing invention, but in any event it must contain a certain degree of utility. in rare cases inventors are able to hit upon an invention in an entirely new field; for these a demand has to be created. for improvements, however, as a general thing, the demand already exists; then the important question arises in determining the commercial value of the patent. "does the invention in question possess sufficient merit to successfully compete with existing devices of the same class?" in order to do this, it must be of a simpler or cheaper construction, so that it can be manufactured and put on the market at a lower figure; or, it must yield better results, work quicker and at less expense, or economize power, labor, or time. a patented improvement upon an article that can be sold more cheaply, or one which will yield better results than those now selling well on the market, has a decided commercial value and can easily be disposed of at a good price. if the inventor be fortunate enough to combine both of these features in his invention, the value is doubled and success certain. [sidenote: basis for estimation.] perhaps one of the hardest questions that confronts the patentee is how to arrive at a just valuation of his patent, and to know just exactly what he should receive for it. this is a very important question, and one which should be looked into before undertaking negotiations. patentees should not, of course, undervalue their patents, or accept the first small offer made for fear of not receiving another; at the same time, they should not fall into the common error of asking a price that cannot be obtained, which too frequently precludes all chances of a sale. many business men would rather lose the patent than waste their time constantly dickering about an unreasonable price. inventors should be reasonable in their demands, and consider that the purchaser must have a fair share of the profits. he cannot expect to realize all there is in the patent himself. indeed, patentees usually find that men willing to establish a business on the basis of their untried patents will require the greater bulk of the profits to be derived from it. [sidenote: general rules for valuation.] it is evident that only the most general rules for valuation can be given, as each invention must be studied and valued strictly upon its own merits. undoubtedly, the best and most practical method of ascertaining the value of any invention which is susceptible of being manufactured on a small scale is to have a limited quantity of the articles manufactured--say five hundred or a thousand--and try the experiment of introducing them in a small territory; that is, in a certain county, city, or town, taking great precaution in selecting a person who is capable of carrying forward the business in a business-like manner. this method demonstrates conclusively whether or not the invention will meet with success, and with these figures at hand the patentee will be prepared to prove, to the satisfaction of interested parties, just what the patent is really worth. this method of procedure not only enables the patentee to get a just valuation of his patent, but also puts it in a more favorable position to be sold; since the commercial value is known and established, it no longer remains an experiment. interested parties can take their calculations from these figures, and the patentee can exact a price in proportion to the success of the trial experiment. in order to thus demonstrate the value of a patent, the patentee must possess and advance the necessary means to carry it forward, though, if the experiment prove at all successful, the profits derived from the articles sold will in nearly all cases more than offset the expense incurred. this is a very popular course with inventors, especially in handling small inventions, known as novelty or specialty patents. if the patentee have not the means to successfully demonstrate the value of his patent by actual trial, as above outlined, then the next best course would be to inquire among reliable manufacturers and ascertain the lowest price for which the invention can be manufactured in large quantities, and the highest price at which it will retail; and then, by carefully studying the market, the patentee should be able to estimate the amount of competition, cost of selling, probable number of sales, interest on the investment, etc., and on these figures base the price he should receive for the patent, being careful to allow the purchaser a liberally fair profit. while there are at present about ninety-five million inhabitants in the united states, it is scarcely probable that any invention has yet or ever will be made that will reach half this number of people. with an article of the most general adaptability, including both sexes, the inventor can hardly hope to reach more than a fourth of the entire population, though, of course, the invention may be subject to regular consumption, so that the people reached would naturally purchase the article again a number of times during the course of a year. the statistics in the last chapter are given with the view of assisting patentees in determining what proportion of the population will likely want their inventions, and to enable them to estimate prices. in estimating the price to ask for a patent, patentees should not conceive and hang their hopes upon fabulous prices and immediate wealth, which too often dooms ambitious inventors to bitter disappointment; they should rather endeavor to look at their inventions from the purchaser's stand-point, and try to see it in the light in which others view it. it may be well to remember that the million mark of patents issued in the united states, including re-issues and designs, was passed in , and it is quite probable that any one inventor may not have the only good thing in the line of patents. [sidenote: how rating for royalty is figured.] many patents are more profitable by being placed upon royalty than by any other means, and quite often the patent can be placed this way when it is not possible to sell outright at a satisfactory price. in determining what royalty the patentee should receive, he should carefully estimate, in connection with the probable number of sales, what profit the manufacturer can probably make on each, or a number of the articles containing the patented improvements, and should require about twenty-five per cent. of the profits as royalty. another method used by some inventors is to ascertain the price at which the article can be retailed, and figure the royalty at between one-twentieth and one-tenth of the retail price. either of the above should give the approximate figure to ask for exclusive royalty contracts. for non-exclusive rights the patentee should ask about one-half of that for exclusive rights. [sidenote: stock in stock companies.] there is another class of patents that can be best realized from by organizing the proper kind of joint stock companies, and manufacturing the invention, the inventor taking a certain amount of the stock and assigning the patent to the company. the patentee should receive between one-fourth and one-half of the capital stock in consideration of his assigning his patent and rights to the company. the inventor should see that a good portion of the stock is subscribed for and the amount actually paid into the treasury of the company before making the assignment. as a rule, inventors' stock is full paid and non-assessable. [sidenote: prices for territorial rights.] in calculating the prices for territorial rights, the application of the invention to that section must be taken into consideration, as well as the advancement in manufacturing, etc. if the invention belongs to that class of inventions which may be generally adapted in all states alike, such as domestic articles and articles of wearing apparel, then the population will form a very satisfactory basis for valuation. there are other inventions, however, that apply almost wholly to a certain section of the country, while still others apply more to one section than to another; thus, for instance, mechanical contrivances of the higher order, such as writing machines, mathematical instruments, etc., the north and east are the most valuable; for mining and agricultural implements, etc., the west; while such as the cotton-gin, seeders, and presses apply almost wholly to the south. states and counties having large cities and large towns are also usually more valuable than other states and counties of same population. [sidenote: valuation tables.] the following tables are given as a general estimate of the relative value of the different states and divisions in the majority of cases; however, these tables are only arbitrary at best, and cannot be applied to all classes of inventions satisfactorily, though they may serve to materially aid the patentee in determining what price to put upon each state in his own case. having determined the value of the patent as a whole, the aggregate of the state prices should be about two-thirds more, as there are always some states that cannot be sold separately, while others may have to be sold at a discount. tables for estimating prices of state rights -----------------+-------------------------------------------------- states and | price as a whole. territories. |---------+---------+----------+----------+-------- | $ , | $ , | $ , | $ , | $ , -----------------+---------+---------+----------+----------+-------- maine | | | | | new hampshire | | | | | vermont | | | | | massachusetts | | | | | , rhode island | | | | | connecticut | | | | | new york | | | | | , pennsylvania | | | | | , new jersey | | | | | +---------+---------+----------+----------+-------- n. atlantic | $ | $ , | $ , | $ , |$ , division | | | | | -----------------+---------+---------+----------+----------+-------- tables for estimating prices of state rights--_continued_ -----------------+-------------------------------------------------- states and | price as a whole. territories. |---------+---------+----------+----------+-------- | $ , | $ , | $ , | $ , | $ , -----------------+---------+---------+----------+----------+-------- delaware | | | | | maryland | | | | | district of | | | | | columbia | | | | | virginia | | | | | west virginia | | | | | north carolina | | | | | south carolina | | | | | georgia | | | | | florida | | | | | +---------+---------+----------+----------+-------- s. atlantic | $ | $ , | $ , | $ , |$ , division | | | | | | | | | | ohio | | | | | , indiana | | | | | , illinois | | | | | , michigan | | | | | wisconsin | | | | | minnesota | | | | | iowa | | | | | missouri | | | | | north dakota | | | | | south dakota | | | | | nebraska | | | | | kansas | | | | | +---------+---------+----------+----------+-------- n. central | $ | $ , | $ , | $ , |$ , division | | | | | -----------------+---------+---------+----------+----------+-------- tables for estimating prices of state rights--_continued_ -----------------+-------------------------------------------------- states and | price as a whole. territories. |---------+---------+----------+----------+-------- | $ , | $ , | $ , | $ , | $ , -----------------+---------+---------+----------+----------+---------- kentucky | | | | | tennessee | | | | | alabama | | | | | mississippi | | | | | louisiana | | | | | texas | | | | | oklahoma | | | | | arkansas | | | | | +---------+---------+----------+----------+-------- s. central | $ | $ , | $ , | $ , |$ , division | | | | | | | | | | montana | | | | | colorado | | | | | new mexico | | | | | arizona | | | | | utah | | | | | idaho | | | | | washington | | | | | oregon | | | | | california | | | | | +---------+---------+----------+----------+-------- western division | $ | $ | $ , | $ , |$ , +=========+=========+==========+==========+======== grand total | $ , | $ , | $ , |$ , |$ , -----------------+---------+---------+----------+----------+-------- chapter v how to conduct the sale of patents while the inventor may put much hard study upon his invention and make many costly experiments, this part of his work is usually a pleasure; and in securing the patent he invariably has able counsel in his attorney with no anxiety on his part; but with the commercial proceeding of selling his patent, which involves the greatest prudence and care in managing, it is different, and here is where the inventor's real work begins if he expects to reap the benefit of his invention. [sidenote: patent-selling agencies.] for the benefit of unexperienced patentees it is deemed expedient to give a word of warning here regarding the host of so-called patent-selling agencies, which under various imposing titles, coupled with an apparently honest and straightforward method of business, tempt each patentee, upon the issue of his patent, to place the same in their hands and authorize them to negotiate the sale thereof. their propositions are very attractive and temptingly prepared; their offers appear to be "gilt edge"; their circulars are high-sounding and rose-colored; their contracts are formal looking, and drawn up in an impressive way, highly advantageous to the patentee; but it will be noted in all cases that they will require the patentee to pay down a certain sum under some pretence,--such as to cover the cost of advertising the patent, to have circulars printed, to secure copies of the patent for distribution, to have a cut made illustrating the invention, or for membership fee, and so on, it matters not what, so long as it is an advance fee. many will also agree to sell both the united states and canadian patents, if the patentee will file the canadian application through them; it is evident, however, that this is only a scheme to get the patentee to take out the canadian patent through them--they having no facilities for disposing of either of the patents. the writer is not prepared to say that there are no honestly conducted patent-selling agencies, but from long experience and observation, has never known where a patentee was ever materially benefited by placing his interests in the hands of these concerns, and has yet to learn of them ever making a sale solely through their own efforts. very few of these concerns have any facilities whatever for selling patents; all of their time being taken up in mailing their weekly circulars to inventors immediately upon the publication of the _official gazette_, and working inventors up to the remitting point which usually ends the matter so far as they are concerned, unless they believe they can get another fee out of the patentee. there may be exceptions, but patentees should fully satisfy themselves as to the integrity of these firms before placing business in their hands, as the assistant commissioner of patents in his report in the webberburn case, o. g., k, clearly pointed out that the methods of these concerns were such as to sell the patentees rather than their patents. [sidenote: the patentee the best selling agent.] that the patentee himself is the best selling agent there can be no doubt, for he is familiar with the construction and operation of his invention in every detail, and knows its merits and superior points far better than anyone else, besides manufacturers and others wishing to purchase patents invariably desire to deal with the patentee himself. business men, it may be said as a rule, do not think very much of an invention which the inventor has abandoned to others to negotiate, moreover the personal push of the inventor is, in nearly all cases, essential to the successful termination of a sale. subtract the personal energy and presence of the inventor from the successful inventions of the past and of to-day, and the chances are that they would not have succeeded as they did. it is not only a question of material interest, but also of enthusiasm and confidence, and each patentee, having but one patent or a set of patents to push, can lend thereto that individual attention which insures good work and success. [sidenote: in case the patentee cannot undertake the selling.] however, if from any reason the patentee is unable to handle his own invention and must engage the services of an agent or salesman, he should select one from among his own acquaintances, in whom he has confidence. he should if possible get a person who has had experience in the line of the invention, as such a person would likely understand it and the trade better than others. it is not really necessary that he should have had experience in selling patents; if he is a good talker, knows how to approach business men, and thoroughly understands the invention, he will probably make money for the inventor and himself. the patentee should have him submit all offers of value for his consideration, and should not give the agent power to sign or collect. the patentee should name a reasonable price for the patent, allowing the agent a liberal commission upon the price, and encouraging the agent by allowing him a certain percentage of all he may be able to get over and above the price named. this will encourage the agent to work for the highest price obtainable. the inventor should make every effort to be able to personally attend to the details of selling, and keep the business under his personal supervision. [sidenote: methods of selling patents.] there are a number of plausible methods to which the patentee may resort in disposing of his patent without the aid of questionable selling agents, and it is the purpose of the following pages and succeeding chapter to set forth such methods as have in the past proved beneficial to patentees; those along which success have been achieved, and such as are employed by the most successful inventors of the present time in handling their patents. it is true that no definite method or system can be given that will apply to all patents alike, as the method in each case will depend more or less upon the character of the invention, and to the particular art to which it belongs; however, from the following pages the patentee should be able to judge what particular methods will best apply to his individual case, and proceed along these lines. there are many patents issued which the patentees thereof can as successfully dispose of from the smallest hamlet in the united states as from new york, chicago, or any of our larger cities, while, of course, there are others which only those directly connected with the largest and wealthiest corporations can hope to dispose of successfully. the main thing is not to become discouraged or give up until one succeeds in making a sale. [sidenote: about advertising.] to make the merits and importance of an invention publicly known is, in many cases, one of the best ways of bringing about the introduction and sale of a patent. if the inventor has a patent on an invention that manufacturers or others want, and can make its merits and superior qualities known to them, negotiations will soon follow. there is no way for patentees to place themselves in communication with prospective investors quite equal to an advertisement in the proper medium. here it may be well to state that patentees who decide to advertise their patents for sale or otherwise should place their advertisements in publications of known standing, such as the leading daily newspapers. a brief, well-worded advertisement in the "business opportunities" column of these papers bring quick and good results, though, perhaps a better class of inquiries may be obtained by advertising in the trade journals of the class to which the invention relates, and while the trade journals may not bring about as many inquiries as the dailies, those that answer will be more apt to be interested and talk business. either of the above are good mediums, but in advertising patents for sale patentees should carefully avoid those publications that are published at uncertain intervals, and usually for the express purpose of circulating among inventors for various purposes. they do not reach the class of people that invest in patents. inventors should know the class of people that would be likely to become interested in their inventions, and advertise in such mediums as have the largest circulation among that class. [sidenote: how to write an advertisement.] in the construction of an advertisement there is often too much waste by using too much verbiage, too many unnecessary words or sentences, sometimes too much display. prudence in the arrangement, and care in editing an advertisement, will save much expense. the size of an advertisement of this class has really little to do with its pulling qualities. the statements should be assuming, and at the same time truthful, as any deception in an advertisement is sure to work an injury. there should not be more claimed in the advertisement than sounds reasonable, even though it be stating facts; if an advertisement sounds unreasonable it will not have the desired result. inventors sometimes become so enthusiastic over their inventions that they exaggerate unintentionally. a good rule is for the inventor to read over the advertisement, and ask himself, "if this statement was read by me, would i believe it; would it convince me?" etc. putting one's self in the purchaser's place is always one of the best factors in writing good advertisements. the inventor should put himself in the place of the purchaser of the patent, and reason what would induce him to investigate its merits; what would likely cause him to take it up, and so on; he should think and write fully along these general lines, incorporate these reasons into an advertisement; then boil it down by cutting out the unnecessary words and sentences; prune, remodel, and rewrite until he has a brief advertisement, clear, concise, and to the point. [sidenote: correspondence as a means of bringing patents before interested parties.] while to advertise, as suggested in the foregoing pages, would require a very moderate outlay, and be, perhaps, the better course to pursue: however, in connection with it, or if the patentee does not feel that he can afford the expense of advertising, a very good plan is for him to secure copies of a number of the trade journals of the class to which his invention relates, and carefully look over the advertisements therein, and select a list of such manufacturers as would seem likely to be induced to purchase the patent in question, or manufacture the article on royalty. in this manner the patentee will probably get the best up-to-date list obtainable, and it may be set down as a fact, with very few exceptions, that if manufacturers and dealers who make and handle just such articles as the patent calls for cannot be interested, it is very hard to interest others not engaged in such line, except when the invention is large, and requires a great deal of capital to work the same. [sidenote: how to correspond with manufacturers.] to each of the parties of the list thus selected, or to a number of them, the inventor should write a well-composed and convincing letter setting forth the invention in its best light, and stating just why it would be to the interest of the parties solicited to investigate the same. some time should be spent on this letter before attempting to write it, and the writer should weigh well in his own mind what would be best to say, and the proper way of expressing it. he should be as brief as possible, consistent with legibility. the statements should be assuming, yet in every respect true. he should state in brief terms just what the invention is, what it will do, the points and advantages it has, and at the same time endeavoring to get the parties interested so that they will inquire into the invention, rather than attempt to come to terms in the first letter. the letter should be brief and pointed, and plainly written upon business-size paper; and if the inventor has a typewriter, or access to one, he should use it. if he has printed circulars he should send one with his first letter, which will enable him to make the letter briefer and more business-like. in correspondence it is well not to name a price until the parties are interested, and first endeavor to get them to make an offer. the patentee should be patient and should not expect to jump right into a bargain at once. if the invention is a meritorious one there will be more than one of the manufacturers to whom the patentee may write, who will become interested, and when such a state exists, the patentee can begin to be more exacting as to his demands since competition has been created between the manufacturers. [sidenote: circulars.] a few dollars invested in circulars will frequently be found of great value to the patentee if he intends to negotiate the sale of his patent mainly by advertising and correspondence, as they will save a great deal of writing and explaining as well as appear more business-like and attractive, and may be the means of more readily effecting a sale. [sidenote: illustrations.] if the patentee can afford the additional expense of an illustration, it will greatly increase the appearance of the circular, and make it more readily understood and interesting. the cut should be neat and set forth the invention in its best light. it would be better to entrust the procuring of the cut to the printer, for he will know just what is wanted and can secure the same at a better price. a sufficient number of well printed circulars, with illustration, can be obtained of any printer for a few dollars. [sidenote: about getting up circulars.] the circulars should be attractive, convincing, and logical; nicely arranged, and neatly printed upon good paper. a mistake is often made in sending out trashy-looking circulars, poorly printed upon cheap paper; they repel rather than attract, and do not have the desired effect. the circular should have good head-lines so as to attract the attention of its recipient at a glance, and his interest should be held by having the uses and advantages of the invention well written. many of the pointers suggested in advertising and letter-writing will equally apply to the writing and getting up of the circulars, and need not be treated further here, except that the patentee should dwell especially upon the merits of the invention, its uses, and advantages over like articles. this should be done in the most interesting manner possible, describing it so that its value will be fully understood. [sidenote: uses of printed copies.] it will be well for the patentee to order some printed copies of his patent, as manufacturers and others usually ask for them if interested, in order that they may examine the patent, or have an expert to examine it, to ascertain its validity, novelty, and what protection is really afforded by the patent. it cannot be denied that in either case the invention will suffer a cold-blooded rigid examination, and must stand or fall solely upon its merits. if, however, the invention is adjudged to have real merit and properly protected by the letters patent, business negotiations will likely begin, and the patentee will perhaps speedily make a satisfactory deal. [sidenote: first impressions all-important.] some inventors use printed copies of their patents instead of circulars, but, while they fully set forth the invention in a technical way, it cannot be said that in all cases it is advisable to send copies of the patent until called for. many parties who become interested in patents are not familiar with mechanical drawings and technical specifications, and very often do not get a very favorable impression from a copy of the patent; and it is very important that the first impressions should be favorably created, for upon this much will depend. if parties become sufficiently interested to fully investigate an invention, they are very apt to form a favorable opinion of it. [sidenote: value of models.] there is no way of so easily creating a favorable impression and gaining the interest in an invention as by a neat and perfect working model of the invention. man never loses the child-love for toys, and a perfect miniature machine of any description will attract more attention than one of full size. with a model the inventor has the full and immediate attention of his prospective purchasers at once. if the patentee, or his agent, intends visiting manufacturers, or to sell the patent by territorial rights, he will find a model of his invention almost indispensable. inventors should be very careful about sending models to unknown parties, and should mark the number of the patent and their name and address upon the model. it should invariably be understood in advance who is to pay the transportation charges, before sending a model with any charges to collect. while models are very helpful in setting forth an invention and making sales, high prices exclude many inventors from their use. model-makers usually charge fifty cents per hour for each man working upon the model, and market price for the material used; from these figures the inventor may make a rough estimate of what a model of his invention will cost. [sidenote: working drawings.] working drawings are different from those forming a part of the patent in that they are more detailed, giving the size of each piece and the material of which it is constructed. while working drawings are not quite as expensive as models, they do not show the invention to the advantage that models do, and are of little value to those who do not understand them. on the other hand, working drawings have the advantage of being easily sent through the mails, and can be duplicated at small cost. manufacturers prefer working drawings to models in quoting prices on manufacturing the invention in quantities. chapter vi how to conduct the sale of patents--_continued_ in conducting the sale of patents, the greatest difficulty is most frequently experienced in getting manufacturers or others sufficiently interested to look into the merits and possibilities of the invention. if the inventor can get the parties to actually consent in their own minds to the proposition of taking up the invention, the question of terms and conditions can soon be arranged. until the parties solicited can see beyond a doubt that there is large profits in it for them, the price of the patent is out of the question; therefore, the first step is to demonstrate its merits and commercial value, and get the parties thoroughly interested. patentees should not labor under the impression that because a patent is offered at a very low price that it will be quickly snapped up as a bargain; as before stated, if a patent will not bring in money by manufacturing and selling the article, it is worthless; and its real value is in exact proportion to the amount of profits that can be made from its manufacture. should the patentee find that his patent has no commercial value, it is almost useless to spend more time and money in trying to realize anything from it; he had better start again, and endeavor to invent something that has value and can be sold. [sidenote: value of personal influence.] inventors should use the full extent of their personal influence to spread particulars of their inventions as far as possible, for this indirect work is often a leading factor in creating a favorable impression that frequently results in the adaption of an invention. however unacquainted he may be in a business way, every patentee can, more or less, in his immediate neighborhood, consult with merchants, friends, and others in the line of his invention, who can post him upon the right parties to submit the patent to, and the best way to see them about it, and perhaps go with him to visit such as might be interested in the invention. [sidenote: personal solicitation advisable.] in nearly every case it is more satisfactory for the patentee to call on the manufacturers or interested parties personally whenever it is possible for him to do so. this brings about a more satisfactory understanding between them. many inventors, however, prefer opening up communication by correspondence, and after the parties manifest a willingness or desire to look into the invention more closely, then arrange to visit them personally. having determined upon a visit, the patentee should endeavor to get a friend known by the parties to go with him to make their acquaintance. if the friend cannot go with the patentee, he will probably give him a note of introduction. it may happen that his friend does not know the parties whom the patentee wishes to see, in that event he may know of someone who does, to whom he can introduce the patentee and who in turn may either go with him or arrange to make him known to the parties solicited. an introduction, of course, is not absolutely necessary, but it invariably has a good effect and is generally worth the effort. the patentee should be prepared to make a straightforward, business-like presentation of his invention by means of a suitable model or drawings; carefully explaining its merits and advantages, showing as clearly as possible just what the value of the invention is and what can be made out of it, and giving tangible reasons why it would be to the interest of the parties solicited to invest in the patent. if the patentee is dealing with a manufacturer it is well to point out not only the possible advantage he may have by securing the control of the patent, but also the possible loss that his business may suffer by allowing one of his competitors to obtain its control. many businesses have been hopelessly crippled by an enterprising firm securing control of a good patent and introducing a like article that can be sold cheaper, or one that will do its work in a better and more satisfactory manner. [sidenote: selling outright.] many inventors prefer to sell their patents outright; that is, in consideration of a specified sum of money the patentee assigns his entire interest in the patent, in the same manner that a person would sell a piece of real estate. this is a very good method and one of the quickest ways for the patentee to turn his invention into money, though it must be remembered that to sell a patent outright is usually for a very much smaller sum than could be realized if handled by other methods. the day for obtaining enormous sums or fortunes from the sale of a patent outright is past; at present to realize any considerable amount, the patentee generally has to share in the risks as well as the profits, unless the invention is very highly developed, and even then he cannot expect to get as much out of an outright assignment as he could by sharing in the success of the invention commercially. if, however, the patentee is content to take the utmost cash his patent will bring him outright, he is assured of a principal or lump sum, free from any chances of the article not selling well when placed upon the market. before signing and delivering the assignment, the patentee will, of course, see that he has the consideration, or its equivalent, for which the assignment is made. if the transaction is made through correspondence he should send the assignment duly executed to the purchaser through the bank or express c. o. d. for the amount. [sidenote: assigning an undivided interest.] in a preceding chapter, the dangers and disadvantages of an undivided interest are set forth, and it cannot be considered a wise course under any consideration to part with any undivided interest in the proprietorship of the patent, unless unusually well paid, or there exists an agreement of copartnership between the patentee and the assignee. by such an assignment, no matter how small, the patentee loses control of his patent. [sidenote: dividing a patent into different classes of rights.] many patents, from the nature of the invention, can be subdivided into different classes of rights, and each class sold or granted separately as the patentee may choose. thus, the patentee of a tire, or other appliances for a bicycle, could license one party to make the same for bicycles and another for automobiles. in like manner a car-coupler could be divided between those who build railway equipments and those who build street-cars, and so on. goodyear, the inventor of the process of vulcanizing rubber, divided his patent up into many different rights, licensing one company for manufacturing rubber combs, licensing another for hose pipes, another for shoes, another for clothing, and a number of other different rights, for which each company or partner paid a tariff. lyall, inventor of the continuous loom, also divided his patent into many different rights; one company weaving carpets, another corsets, another bags, another sheeting, etc. in every case where the invention covers articles not in the same line of manufacture, the patentee should not fail to divide the rights into different classes, granting each party only such rights as they may be interested in. in this way the patentee can quite often double or treble the receipts from his invention. the patentee may, if he desires, have his machines built and require the purchasers to pay him a regular annual rental on each machine, or a tariff upon the goods produced, in addition to the price of the machine. companies are sometimes organized to manufacture an invention, and employ travelling men to place the article on annual rental instead of selling. [sidenote: selling by territorial rights.] another method is to sell state and county rights. this consists of a license whereby the patentee, in consideration of a certain sum of money paid him, grants unto another person or persons the exclusive right to make and sell the invention, and to authorize others to make and sell the same, within a specified territory, during the life of the patent. this plan of disposing of a patent has often been highly profitable, but it must be said that these territorial sales have been conducted in such a manner in the past, as to bring the whole system of selling patent rights into disrepute, and in recent years patentees have found some difficulty in making sales in this way, unless the device is of unusual great novelty and attraction to householders or the general public. occasionally, however, there are patents issued for meritorious inventions that are susceptible of this mode of procedure, and which can be disposed of to the greatest advantage by territorial grants. such inventions as household novelties possessing great merit and utility have been most successfully placed upon this plan, but it must be remembered that the value of the system rests upon its capabilities of effecting sales of the manufactured article to a vast proportion of the people. in selling territorial rights it is a mistake to begin with the small places with the idea of working the business up and effecting larger sales on the basis of the smaller ones; it is better to shove the sales, as much as possible in the start, and after the more valuable portion of the territory is disposed of, proceed with the balance until it ceases to be profitable. experience teaches that it is usually advisable to accept any reasonable offer made for a small right, even if it does not come up to the patentee's estimate of its value, as he has plenty of other territory left, and may lose much time and money in finding another in the same territory willing to pay more; besides, the purchaser of such a right may, by his energy and good judgment, advertise the invention in such a way as to greatly benefit the patentee in making further sales. some patentees employ good and reliable special agents to travel and dispose of the patent rights; others advertise for and appoint state agents to sell their respective county rights. in either case these agents expect to make money by the operation, and require a liberal proportion of the proceeds for their remuneration; generally speaking, they will require about one-third the selling price, unless the patentee can show that the rights will sell readily, in which case the rating can be made lower. [sidenote: granting licenses.] the patentee may also sell licenses under his patent; that is, in consideration of a certain sum, the patentee licenses a manufacturer to make the invention at his own place of business; it being a personal privilege and is not transferable unless its terms so state. unless there are a great many manufacturers in the line of industry to which the patent relates, and unless the invention has real merit so that it will be readily adapted by the manufacturers, the patentee cannot hope to realize any considerable amount from selling shop-rights alone. as a general thing, patents for mechanical inventions can be disposed of to better advantage by other means, or by selling shop-rights in connection with other methods; for example, if the patentee was selling his patent by territorial grants, he might grant shop-rights in such territory as he has not sold; or if he is placing the patent upon non-exclusive royalty contracts, he could grant shop-rights in such portions of the territory as he does not contemplate using otherwise. some inventions, such as methods or processes, as a general rule, have to ultimately be sold by licenses. such patents can be employed most profitably by selling licenses, county and state rights; thus, in the case of a method of constructing fences, the patentee could sell state and county rights to parties, who in turn could grant farm rights, etc. [sidenote: placing upon royalty.] the license and royalty plan is perhaps the best and most popular method with inventors for realizing from their inventions. this, in effect, involves a contract between the patentee and the manufacturer, by which the latter in consideration of a license to manufacture the article covered by the patent, agrees to pay the patentee a certain specified sum as royalty for each article manufactured or sold bearing the patented improvement. placing a patent on royalty is ordinarily taking chances, but if the patentee has full confidence in his article selling well, he should by all means take royalty in preference to selling the patent in its entirety. many valuable patents are sold by their owners for from $ , to $ , , which yield the purchasers, when the article is on the market and selling well, as much as $ , annually in profits. this calls to the author's mind a patent for which at the outset was doubtfully offered $ , , but before the negotiations terminated, the patentee succeeded in placing it upon an exclusive royalty basis. the royalties paid to the patentee during the first four years amounted to over $ , , and the manufacturers subsequently made an offer of $ , , for the patent. in making royalty contracts with parties, the patentee should investigate the standing, rating, and capabilities of the manufacturer, and, above all, should be certain that the parties have the right motive in view, and that the contract is so drawn that it will fully protect his own interests. many patentees have been caught by manufacturers offering large royalties for the sole purpose of gaining possession of the patent, that they might pigeon-hole it, in order to keep the article out of the market, so that the sale of some similar article in which they are interested would not be interfered with by the introduction of a similar or better article, such as the patent anticipates. there are others who propose and make royalty contracts with patentees with no other object than that of making the special tools, patterns, dies, etc., for which they charge the patentee an extortionate price. the best and safest way for the patentee to guard against having his patent tied up is to bind the parties to do certain things in the way of pushing the sales, making the necessary tools at their own expense, and commencing its manufacture within a reasonable time, paying an advance royalty, or annexing some such condition to the agreement by which they will be the loser should they fail to push the inventor's interests. unless it cannot be otherwise arranged, the patentee should not transfer his rights merely in consideration of receiving a certain sum on each article sold, as however sterling the character of the manufacturer, there would be no certainty of the sales being pushed. the patentee should endeavor to get the manufacturer to guarantee that the royalties shall amount to at least a certain pre-stipulated sum each year, or within a period of time, and that such sum shall absolutely be paid to him by the manufacturer, irrespective of sales. this insures that the manufacturer will be obliged to push the sales of the article, and do it justice, since if he neglects his duty purposely, or from lack of energy, he is out of pocket, and the patentee is sure of a certain income, with the addition of a possible fortune that unprecedented sales may yield him. however, manufacturers are not always willing to agree to this condition, unless the guaranteed amount is exceedingly reasonable; they will usually simply agree to do their best, and if the sales do not reach a certain figure each year, the patentee shall have the option of cancelling the agreement, and receiving back the patent free and clear. royalty licenses can either be exclusive or non-exclusive; that is, with an exclusive contract the manufacturer has the exclusive right to manufacture the article, excluding all others; non-exclusive is simply a shop-right, in consideration of which the manufacturer agrees to pay the patentee or owner of the patent a stipulated price or percentage upon each article made or sold. the license can also be exclusive in a certain section, county, state, or a number of states, as may be agreed upon. any number of conditions that may be agreed upon may be annexed to and form a part of the contract, and such an agreement should be drawn up in compliance with the terms and conditions agreed upon by a competent attorney, or one skilled in matters of this kind. [sidenote: manufacturing and forming companies.] if the patentee has a really good invention, often he cannot do better than to retain the patent and work it himself, in case he has the ability to do so. if he cannot conduct the manufacturing alone, he may be able to secure a partner with just sufficient funds, and equal common sense and business acumen, to add the necessary elements to the firm to achieve success. in some cases, if the patentee does not wish to retain the whole patent for his own use, an excellent plan is to commence the manufacture of the invention in a suitable locality, and after the business is so far under way as to show progress and profit, then sell out the business with license under the patent. to illustrate: a gentleman in illinois, having obtained a patent on a farming implement, succeeded in interesting a party in his own neighborhood to join with him in its manufacture, which soon proved successful and remunerative, and in a short time he was able to sell out his interest in the business to his partner, with license under the patent, after which the patentee started its manufacture in a number of places elsewhere, and, at the same time, granting licenses and selling territory in still other sections, where he was unable to work the invention. in this way he made a fair fortune from his invention, realizing about as much from each business established as he could have probably obtained for the entire patent if sold outright at first. in this manner the patentee, with a valuable patent on an article of general usefulness, could go on and establish its manufacture in any number of places, and sell out with license under the patent. if the first experiment is successful, it is an easy matter to carry the method out in other places, and the business can be readily disposed of anywhere, if it can be shown to be on a paying basis. [sidenote: to organize stock companies] in recent years many inventors have been quite successful in organizing stock companies on the basis of their patents. this is considered one of the best ways for handling patents for large and promising inventions, and it is a method that any patentee, with ordinary business ability, should be able to carry out successfully, providing his invention is of sufficient merit and importance to form a suitable basis for a successful stock company. many stock companies are incorporated under the laws of new jersey, but it is believed the state of west virginia is also very favorable to corporations. the entire expense for incorporating a company under the laws of the latter state should not exceed $ . the company can be incorporated for any amount; large or small, one hundred dollars or five millions, cost and fees being the same. the incorporators need not be residents of the state. no annual statements required. the meetings of the directors can be held at any place, and need not be held in the state where the charter is granted. before applying for a charter for a corporation or stock company, the patentee should mention his plan to some of his friends and get five persons who will promise to subscribe for one or more shares of the stock and act as incorporators of the company. next he should secure the services of a reliable attorney, familiar with corporation laws, to prepare the necessary articles of incorporation and legal papers. the attorney will advise the patentee how to proceed properly in organizing his company, and as to the securing of the stock certificates, subscription blanks, seal, etc. these, including the attorney's fee, should not cost the patentee more than $ . it is well to have some stationery printed with the proposed name of the company and business displayed thereon; and also a prospectus published, setting forth the invention and the plans of the company for introducing it, etc. quite often the patentee can find enough idle capital in his immediate neighborhood to float a good portion of the stock. capital is more easily secured by the formation of a stock company than by any other means, as people can subscribe for small or large amounts, and they often prove good investments. in soliciting subscriptions for stock, it is desirable to get as many prominent and influential men to buy one or more shares at first to head the list--their names will be a great aid in making further sales. ordinarily the promoter only collects ten per cent, of the amount subscribed, the balance being subject to the call of the board of directors. after it is ascertained that the shares or stock are being rapidly subscribed for and selling fully up to expectation, the patentee can have the incorporators sign the charter application and have the attorney file it with the proper state authorities. this will cost the patentee about $ more, for state tax, attorney fees, etc. when sufficient stock has been subscribed for, a meeting of the stockholders should be called to elect directors, and to transact such other business as may be deemed necessary in regard to locating and building the plant and getting the company in shape. the patentee should receive about one-half the capital stock in consideration of his transferring his rights and franchises to the corporation, the remainder of the stock is sold for the benefit of the company to create a working capital. the patentee may sell a portion of his stock, if he desires, but should also retain a good portion of it to show his own confidence in the business. after the meeting of the stockholders, the direction of the business will probably be taken out of the hands of the inventor, and the control will lie in the board of directors of the company. as a rule it is better that the inventor does not take an active part in the management of the company's affairs, unless he is specially fitted for the position. if the company is provided with ample capital, and if the business manager is a competent man, there is little chance of failure if the invention has real merit. [sidenote: trading as a last resort.] patentees are sometimes offered securities or other property in trade for a patent. it is not deemed a wise course by most inventors to consider any proposition for a trade, especially in the early life of a patent. only as a last resort, after failing to realize from a patent by any other means, is it advisable to trade a patent; and, before finally agreeing upon a trade, the patentee should have a reputable attorney to look fully into the value and title of the property offered. he should also insist upon receiving an abstract of title, or a title guarantee from a reliable title insurance company. unless known to himself, the patentee should never engage the services of an attorney or broker recommended by the parties offering the trade to look into the value and title of the property. inventors should be on the lookout for a set of sharpers who make a business of offering worthless securities and property in exchange for patents. chapter vii about canadian patents the geographical nearness of canada to the united states, and the intimate commercial relations existing between the two countries, render canada, in one sense, a part of the industrial market of america; and owing to its liberal patent laws, which are based closely upon our own, inventors generally find it advantageous to protect their interests in this country, which can be done from time to time by a very small outlay, and thus giving the inventor the advantage of disposing of his patent or dropping it if not found remunerative, before expending the total cost of the patent. the commercial and manufacturing interests of canada are extensive, increasing yearly, and are closely knit with our own. if the invention is not protected in canada, it is sometimes manufactured there and sent here without paying royalty to the inventor. copies of the "rules and forms of the canadian patent office" and "the patent act" can be obtained upon application to the hon. commissioner of patents, ottawa, canada. section of the patent act, revised may, , provides: "any inventor who elects to obtain a patent for his invention in a foreign country before obtaining a patent for the same invention in canada, may obtain a patent in canada, if the same be applied for within one year from the date of the issue of the first foreign patent for such invention; and, "if within three months after the date of the issue of a foreign patent, the inventor give notice to the commissioner of his intention to apply for a patent in canada for such invention, then no other person having commenced to manufacture the same device in canada during such period of one year, shall be entitled to continue the manufacture of the same after the inventor has obtained a patent therefor in canada, without the consent or allowance of the inventor." the patent act as amended does not now require a canadian patent to expire at the earliest date at which a foreign patent for the same invention expires. under the section just cited the patentee has three months, after the issue of his patent, within which to protect his interests in canada. if within these three months he has not sufficiently demonstrated the commercial value of his home patent, and the advisability of taking out a canadian patent, he is advised to give notice to the commissioner of patents, ottawa, of his intention of doing so, which will fully protect his interests for one year, as under the above provision; and if the patentee fail to give this formal notice, he cannot obtain redress from any person who has commenced to manufacture his invention in canada during the year. there is also an advantage sometimes in giving this formal notice within three months and delaying the grant of the patent for one year, as the patentee is allowed to import the patented article into canada during one year only, after the grant of the canadian patent. the construction or manufacturing of the invention in canada must be commenced within two years from the date of the patent, and continuously carried on from that time, though the extension of this time may be secured upon timely application to the commissioner, giving any good and proper reason. the time for importation is also sometimes extended upon proper application. canadian patents are granted originally for a term of eighteen years, the government fee being $ for the eighteen years, but at the election of the patentee this fee may be divided into three payments of $ each, as follows: $ at the time of the grant, $ at the expiration of the sixth year, if the owner desires to keep the patent alive, if not he can allow the patent to become forfeited; and at the end of the twelfth year, if it is still desired to maintain the patent, the remaining fee of $ may be paid. if the patentee in the meantime assigns his patent, the assignee will pay the required government fees at the end of the sixth and twelfth years, if it is desired to maintain its validity. the canadian patent covers and affords full protection in the following provinces: ------------------------+----------+------------- provinces. | area | population |sq. miles.| ------------------------+----------+------------- alberta | , | , british columbia | , | , manitoba | , | , new brunswick | , | , nova scotia | , | , ontario | , | , , prince edward island | , | , quebec | , | , , saskatchewan | , | , northwest territories | , , | , yukon | , | ---- |----------+------------ total | , , | , , ------------------------+----------+------------ [sidenote: selling canadian patents.] in selling canadian patents, the patentee will proceed in much the same way as in the united states, though he cannot expect, nor should he ask, more than about one-third as much for the canadian patent as he receives, or expects, from the united states patent. patents are not as readily sold in canada as here, but if the inventor has a useful invention of merit, which is being manufactured profitably in the united states, he will have no trouble in disposing of his canadian patent at a satisfactory price. it is in nearly all cases advisable for the inventor to first put his invention upon the market in the united states before trying to realize from his canadian interests, as it will be found difficult to interest canadian capital in a patent that has not been first put into practice here; and if the patentee be able to dispose of his canadian patent at all, it is usually for a very insignificant sum; whereas, on the other hand, if the patentee fully protects his interests there, and proceeds to put the invention upon the home market, he will not only be able to present his canadian patent in a more favorable and forcible way by proving its commercial value, but he will undoubtedly get better offers, and realize full value for his canadian interests, in exact proportion to the success of his invention in the united states. population of canadian cities (_compiled from the census of _) montreal , | new westminster , toronto , | stratford , winnipeg , | owen sound , vancouver , | st. catharines , ottawa , | saskatoon , hamilton , | verdun , quebec , | moncton , london , | port arthur , halifax , | lachine , calgary , | chatham , st. john , | galt , victoria , | sault ste. marie , regina , | sarnia , edmonton , | belleville , brantford , | st. hyacinthe , kingston , | valleyfield , maissonneuve , | brockville , peterboro , | woodstock , windsor , | niagara falls , sydney town , | sorel , hull , | nanaimo , glace bay , | lethbridge , fort william , | vancouver, north , sherbrooke , | north bay , vancouver, south , | st. boniface , berlin , | sydney mines , guelph , | levis , st. thomas , | oshawa , brandon , | collingwood , moose jaw , | fredericton , chapter viii decisions and notes the following digest will be found to contain much useful information for the patentee, it being a carefully selected list of decisions affecting assignments, territorial grants, licenses, state laws, etc.; including those rendered by the supreme court of the united states, the circuit court of appeals, state courts, and of various commissioners of patents, all of which decisions enunciate well-settled and controlling principles of patent law. [sidenote: assignments.] assignments of patents are not required to be under seal. the statutes simply provide that "every patent, or any interest therein shall be assignable in law by an instrument in writing." (_gottfried_ vs. _miller, u. s. s. c. decided jan. , ._) a contract assigning a patent and all future improvements thereon is enforceable against assignees of such improvements who take notice of the contract. (_westinghouse air brake co._ vs. _chicago brake and mfg. co., f. r., ._) each co-owner of a patent may use his right without the concurrence of the others and license at will. (_washburn & moen co._ vs. _chicago wire fence co., ill., ._) owners of a patent are tenants in common, and each, as an incident of his ownership, has the right to use the patent or manufacture under it. but neither can be compelled by his co-owner to join in such use or work, or be liable for the losses which may occur, or to account for the profits which may arise from such use. (_de witt_ vs. _elmira nobles mfg. co., n. y. spur., ._) joint owners of a patent, right are not copartners, and in the absence of any express contract each is at liberty to use his moiety as he may think fit, without any liability to or accounting to the other for profits or losses. (_vose_ vs. _singer, allen (mass.), ; vide pitt vs. hall, blatch., ._) although an assignment of patent is not recorded within three months, it is binding on the assignor, and he cannot sell the patent again. (_ex parte waters, com. dec., , p. ._) a verbal license or interest in an invention has no effect as against a subsequent assignee without notice of such verbal license or interest. (_u. s. s. c., gates iron works_ vs. _fraser et al., , c. d., ._) an assignment to assign future patents, in consideration of the assignee's paying the expense of taking them out, is broken by his refusal to pay for and take out a particular patent when requested, and a subsequent assignment to another conveys a perfect title. (_buck_ vs. _timony, fed. rep., ._) any assignment which does not convey to the assignee the entire and unqualified monopoly which the patentee holds in the territory specified, or an undivided interest in the entire _monopoly,_ is a mere license. (_sanford_ vs. _messer, o. g., ._) when a party does license, grant, and convey any invention which he may hereafter make, this gives only an equitable right to have an assignment made, and this right may be defeated by assignment of the patent to a purchaser for value without notice of this equity. (_regan vapor engine co._ vs. _pacific gas engine co. (nineth cir.), u. s., app., ._) [sidenote: territorial grants.] a territorial grantee cannot be restrained from advertising and selling within his territory, even though the purchasers may take the patented article outside the vendor's territory. (_hatch_ vs. _hall, fed. rep., ._) one who buys patented articles of manufacture from an assignee for a specified territory becomes possessed of an absolute property in such articles, unrestricted in time or place. (_u. s. s. c., keller et al._ vs. _standard folding bed co., o. g., ._) the sale of a patented machine by one authorized to sell, conveys the whole ownership to the purchaser, who may sell it again to another. (_morgan envelope co._ vs. _albany perforated wrapping paper co., u. s. ._) [sidenote: licenses.] every person who pays the patentee for a license to use his process becomes the owner of the product, and may sell it to whom he pleases, or apply it to any purpose, unless he binds himself by covenants to restrict his rights of making and vending certain articles that may interfere with the special business of some other licensee. (_met. washing machine co._ vs. _earl, fish., ; wall., jr., ._) a license is not forfeitable for non-payment of royalties in the absence of express provisions to that effect. (_wagner typewriter co._ vs. _watkins, fed. rep., ; ._) a shop right is a personal license and is not assignable. (_gibbs_ vs. _hoefner, fed. rep., ; blatch., ._) a license to a person to use an invention only "at his own establishment" does not authorize a use at an establishment owned by him and others. (_rubber co._ vs. _goodyear, wallace, ._) a license is not transferable unless its terms so state. (_olmer_ vs. _rumford chemical co., u. s., ._) a license merely to make and not to sell does not impair the patent owner's right to sue for infringement outside of the license; and the purchaser of the licensee's tools and materials would not carry the right to sell the product made thereon. (_american graphophone co._ vs. _walcut, fed. rep., ; ._) a license to use a machine carries with it the right to repair the machine, and replace worn parts until the essential original parts of the machine have disappeared. (_robinson on patents, sec. ._) a lawful sale of a patented article by a patentee or grantee, within his own territory, carries with it the right to use such article throughout the whole united states. (_adams_ vs. _burke, o.g., _; _hobbie_ vs. _smith. fed. rep., ._) when an applicant in certain instruments assigned his right, title, and interest in an invention, retaining for himself the exclusive right to employ the invention in the manufacture of a certain class of machines, held, that such instruments do not convey the entire interest in the invention or any undivided part thereof, and they are construed to be nothing more than licenses. (_ex parte rosback, o. g., . decided oct. , ._) an implied license to use a patented improvement without payment of any royalties during the continuance of employment of the inventor, and thereafter, on the same terms and royalties fixed for other parties, is shown where the inventor applies the patent to his employer's work without any agreement for compensation for its use further than a notice that he would require pay after his employment terminated. (_keys_ vs. _eureka consol. min. co., u. s. s. c., u. s., ._) a breach of a covenant in a license does not work a forfeiture of the license unless it is so expressly agreed. (_consol. middlings purifier co._ vs. _wolf, o. g., ._) [sidenote: patent title.] a patent right, like any other personal property, is understood by congress to vest in the executors and administrators of the patentee, if he dies without having assigned it. (_shaw relief valve co._ vs. _city of new bedford, th fed. rep., ._) a patent to a dead man at the time of its grant is not void for the want of a grantee, but vests in his heirs or assigns. (_u. s. s. c, de la vergne ref. machine co._ vs. _featherstone, , c. d., ._) a court of equity may direct a sale of an inventor's interest in his patent to satisfy a judgment against him, and will require the patentee to assign as provided in rev. stat., sec. , and if he refuses, will appoint a trustee to make the assignment. (_murray_ vs. _ager, o. g., ._) a patent right cannot be seized and sold on execution. (_carver_ vs. _peck, mass., ._) a receiver cannot, under his general powers, convey the legal title to a patent (_adams_ vs. _howard, blatch., _), but a court may compel an insolvent to assign his patent to a trustee or receiver. (_pacific bank_ vs. _robinson, o. g., _; _murray_ vs. _ager, o. g., ._) a patentee who assigns his patent cannot, when sued for infringement, contest the validity thereof. (_griffith_ vs. _shaw, fed. rep., ._) rules of practice the following from the "rules of practice in the united states patent office" may be perused with interest to the patentee; a copy of which, together with a copy of the "patent laws," will be mailed free to any person upon addressing the hon. commissioner of patents, washington, d. c., requesting the same; these being the only books or pamphlets published by the office for gratuitous distribution. [sidenote: assignments.] every patent or any interest therein shall be assignable in law by an instrument in writing; and the patentee or his assigns or legal representatives may, in like manner, grant and convey an exclusive right under the patent to the whole or any specified part of the united states. interests in patents may be vested in assignees, in grantees of exclusive sectional rights, in mortgagees, and in licensees. [sidenote: assignees.] an assignee is a transferee of the whole interest of the original patent or of an undivided part of such whole interest, extending to every portion of the united states. the assignment must be written or printed and duly signed. [sidenote: grantees.] a grantee acquires by the grant the exclusive right under the patent to make and use and to grant to others the right to make and use, the thing patented within and throughout some specified part of the united states, excluding the patentee therefrom. the grant must be written or printed and be duly signed. [sidenote: mortgages.] a mortgage must be written or printed and duly signed. [sidenote: licensees.] a licensee takes an interest less than or different from either of the others. a license may be oral, written, or printed, and if written or printed, must be duly signed. [sidenote: must be recorded.] an assignment, grant, or conveyance of a patent will be void as against any subsequent purchaser or mortgagee for a valuable consideration without notice unless recorded in the patent office within three months from the date thereof. if any such assignment, grant, or conveyance of any patent shall be acknowledged before any notary public of the several states or territories, or the district of columbia, or any commissioner of the united states circuit court, or before any secretary of legation, or consular officer authorized to administer oaths or perform notarial acts under section of the revised statutes, the certificate of such acknowledgment, under the hand and official seal of such notary or other officer, shall be _prima facie_ evidence of the execution of such assignment, grant, or conveyance. no instrument will be recorded which does not, in the judgment of the commissioner, amount to an assignment, grant, mortgage, lien, encumbrance, or license, or which does not affect the title of the patent or invention to which it relates. such instruments should identify the patent by date and number; or, if the invention is unpatented, the name of the inventor, the serial number, and date of the application should be stated. [sidenote: conditional assignments.] assignments which are made conditional on the performance of certain stipulations, as the conditional payment of money, if recorded in the office are regarded as absolute assignments until cancelled with the written consent of both parties, or by the decree of a competent court. the office has no means for determining whether such conditions have been filled. (_rev. stat., sec. ._) state laws on selling patents in some states, laws have been passed by which attempts have been made to regulate or prevent the sale of patent rights within their borders, by imposing upon patentees or their agents certain state restrictions, such as requiring the filing of copies of patents, making and filing proofs, taking out licenses, procuring certificates, complying with forms, or prescribing the terms of a note to be given for a patent. while it has never been squarely brought before the united states supreme court, with the result that much conflicting legislation has been enacted by the different states, it may be said, as a general proposition, that a state or municipality, through the medium of its legislature or officials, has no constitutional right to make or enforce laws which in any way affect or control the transfer, sale, or other disposition of united states letters patent; or to interfere in any manner with the patentee going into the open market anywhere to sell his rights conferred by the patent. it is a well-established principle of law that congress has exclusive right and power to legislate on the subjects specially assigned to it by the constitution, while power is delegated to the several states to legislate on those subjects not thus expressly placed within the control of congress. it would seem clear that there can be no state interference with the rights which are incident to the grant of letters patent and expressly conferred thereby. ohio was the first state attempting to place restrictions upon the handling of patent rights, which, in , passed an act requiring any person, before offering for sale a patent right in any county, to submit the patent to the probate judge of the county, and make affidavit before said judge that the patent was in force, and that the applicant had the right to sell, and also requiring that any written obligation taken on the sale of such right should bear on its face the words, "given for a patent right." the portion of the ohio statute relating to the making and filing proofs was subsequently made the law in illinois, minnesota, indiana, nebraska, and kansas, while the requirement that written obligations given for a patent right should bear such statement written upon its face was made the law in vermont, michigan, pennsylvania, wisconsin, new york, connecticut, and arkansas. in view of the decisions rendered by the supreme court of the united states in the cases of _ex parte_ robinson, bissel, , and webber _vs._ virginia, u. s., ; o. g., , some of the states repealed their statutes relating to the filing of proofs, while others did not--notably indiana and kansas, where the statute still remains in force. while the supreme court in the above cases did not decide the constitutionality of the state statutes, it was clearly indicated that property in inventions existed by virtue of the laws of congress, and that no state had any right to interfere with its enjoyment, or to annex conditions to the grant, and that the patentee had a right to go into the open market anywhere in the united states and sell his property. it also established the proposition that a state may require the taking out of a license for the sale of the manufactured article covered by the patent; and the patentee should keep in mind the distinction between selling patents, or patent privileges, and the selling of goods or manufactured articles, as all who sell goods, whether patented or not, must conform with the local and state laws relating to same. the statute requiring the insertion in written obligations of the words, "given for a patent right," has been declared unconstitutional by the higher state courts in illinois, michigan, minnesota, and nebraska, and by the circuit courts in the southern district of ohio, and in the district of indiana; while its validity has been sustained by the courts of last resort in new york, pennsylvania, ohio, indiana, and kansas. therefore, the validity of the state statutes on the point referred to may be regarded as finally established in the last-named states until brought before the supreme court of the united states. chapter ix the transfer of patent rights it frequently occurs to the patentee that a knowledge of the legal requirements of the transfer of patent rights would save him much time and trouble. patentees should carefully scrutinize all papers offered by the parties in whose favor they are drawn, and, if possible, he should have his attorney to examine them. there are three classes of persons in whom the patentee can vest an interest of some kind. they are an assignee, a grantee of an exclusive sectional right, and a licensee. [sidenote: assignee, grantee, and licensee defined.] "an _assignee_ is one who has transferred to him in writing the whole interest in the original patent, or any undivided part of such whole interest in every portion of the united states. and no one, unless he has such an interest transferred to him, is an assignee. "a _grantee_ is one who has transferred in writing the exclusive right under the patent, to make and use, and to grant to others to make and use, the thing patented, within and throughout some specified part or portion of the united states. such right must be an exclusive sectional right, excluding the patentee therefrom. "a _licensee_ is one who has transferred to him in writing, or orally, a less or different interest than either the interest in the whole patent, or an undivided part of such whole interest, or an exclusive sectional interest." (_potter_ vs. _holland, fish, ._) [sidenote: the language of law.] if a man were to give another an orange he would simply say, "i give you this orange"; but if the transaction be intrusted to a lawyer to draw up according to the requirements of law, says the _observer_, he would most probably put it in the following language: "i hereby give, grant, and convey to you all my interest, right, title, and advantage of and in said orange, together with its rind, skin, juice, pulp, and pits, and all right and advantage therein with full power to bite, suck, cut, or otherwise eat the same or to give the same away, as fully and effectually as i, the said a. b., am now entitled to cut, bite, or otherwise eat the same, or give away the same with or without the rind, skin, juice, pulp, or pits; anything hereinbefore or hereafter or in any other deed or deeds, instruments of nature or kind whatsoever to the contrary in anywise notwithstanding." it is always better and more satisfactory to have assignments, royalty contracts, agreements, etc., drawn up specially to accord with the facts, details, and covenants of each particular case; and there is no one probably better able to do this than the attorney who secured the patent. however, if in the case the parties to the transaction cannot well delay proceedings to have the papers prepared by an attorney, by adhering to the following forms in any such transactions, both the purchaser and seller may rest assured that their rights are protected. assignment of entire interest in letters patent _whereas_, i, richard doe, of columbus, county of franklin, state of ohio, did obtain letters patent of the united states for an improvement in typewriting machines, which letters patent are numbered , , and bear date january , ; and whereas i am now sole owner of said patent, and of all rights under the same; and whereas the ohio typewriter company, a corporation, of cincinnati, county of hamilton, and state of ohio, is desirous of acquiring an interest in the same: _now, therefore_, to all whom it may concern, be it known, that for and in consideration of the sum of five thousand dollars to me in hand paid by the aforesaid corporation, the receipt of which is hereby acknowledged, i, the said richard doe have sold, assigned, and transferred, and by these presents do sell, assign, and transfer unto the said ohio typewriter company, its successors and assigns, the entire right, title and interest in and to said letters patent and the invention therein patented; the same to be held and enjoyed by the said corporation for its own use and behoof, and for the use and behoof of its successors and assigns, to the full end of the term for which said letters patent are or may be granted, as fully and entirely as the same would have been held and enjoyed by me had this assignment and sale not been made. _in testimony whereof_, i have hereto set my hand and affixed my seal, at columbus, county and state aforesaid, this tenth day of january, a.d. . richard doe. (_seal._) in presence of john smith, thos. jones. state of ohio, }_ss._: county of franklin, } subscribed and acknowledged before me this tenth day of january, a.d. . _seal._ john rice, _notary public_. if it is the intention of the assignor to convey to the assignee the right to recover for past infringement of the patent, a clause like the following should be added: and for the same consideration, i do hereby sell, assign and transfer unto the aforesaid corporation, all claims and demands, both at law and in equity, which may have accrued to me by reason of the infringement of the aforesaid letters patent with the right to sue and recover therefor in its own name and for its own use and behoof. assignment of an undivided interest _whereas_, i, richard doe, of philadelphia, county of philadelphia, state of pennsylvania, did obtain letters patent of the united states for improvements in locomotive headlights, which letters patent are numbered , , and bear the date of june , ; and whereas, john roe, of philadelphia, county of philadelphia and state of pennsylvania, is desirous of acquiring an interest in the same: _now, therefore_, this indenture witnesseth, that for and in consideration of the sum of one thousand dollars to me in hand paid by said john roe, the receipt of which is hereby acknowledged, i do hereby sell, assign, and transfer unto the said john roe, his heirs and assigns, one undivided one-half interest in and to the aforesaid letters patent and the invention therein patented; the same to be held and enjoyed by the said john roe, his heirs and assigns to the full end of the term for which said letters patent are or may be granted as fully and entirely as the same would have been held and enjoyed by me if this assignment and sale had not been made. and i do hereby declare that i have not conveyed to any other party the rights and interest herein transferred to the said john roe. witness my hand and seal this tenth day of january, a.d. , richard doe. in presence of john smith, thos. jones. state of penna., } _ss._: county of philadelphia,} subscribed and sworn before me this tenth day of january, a.d. . _seal._ john rice, _notary public._ grant of a territorial interest _whereas_, i, richard doe, of dayton, county of montgomery, state of ohio, did obtain letters patent of the united states for improvements in corn-cultivators, which letters patent are numbered , , and bear date the first day of january, , and whereas, i am now the sole owner of said patent, and of all rights under the same in the below-recited territory; and whereas, john roe, of indianapolis, county of marion, state of indiana, is desirous of acquiring an interest in the same; _now, therefore_, to all whom it may concern, be it known, that for and in consideration of the sum of one thousand dollars to me in hand paid, by the said john roe, the receipt of which is hereby acknowledge, i, the said richard doe, have sold, assigned, and transferred, and by these presents do sell, assign and transfer unto the said john roe, his heirs and assigns, the entire right, title and interest in and to said letters patent, and in and to the invention therein patented for the states of indiana and illinois, and in no other place or places; the same to be held and enjoyed by the said john roe, his heirs and assigns, within and throughout the above specified territory, but not elsewhere, to the full end of the term for which said letters patent are or may be granted, as fully and entirely as the same would have been held and enjoyed by me had this assignment and sale not been made. _in testimony whereof_, i have hereunto set my hand and affixed my seal this tenth day of january, a.d. , in the presence of the subscribing witnesses. richard doe. in presence of john smith, thos. jones. state of indiana, }_ss._: county of marion, } on this tenth day of january, a.d. , personally appeared before me richard doe, to me known and known to me to be the individual who executed the foregoing instrument, and who acknowledged to me that he executed the same for the purpose therein expressed. _seal._ john rice, _notary public._ license:--shop-right _in consideration_ of the sum of two hundred dollars to me paid by the john roe company, a corporation of pennsylvania, located in the city of pittsburg, i do hereby license and empower said company to make and use at its foundry and machine shop in said pittsburg, and in no other place or places, in connection with its own business only, or that of its successors and assigns, the improvements in lathes, for which letters patent of the united states no. , , were granted to me january , , to the full end of the term for which said letters patent are granted. signed and delivered at pittsburg, in the county of allegheny, state of pennsylvania, this tenth day of january, a. d. . richard doe. to john roe company, pittsburg, pa. license:--non-exclusive--with royalty _this agreement_, made this tenth day of january, , between richard doe, of wilmington, county of new castle, state of delaware, party of the first part, and the metallic railway tie company, of chicago, in the county of cook, and state of illinois, party of the second part, _witnesseth_, that whereas letters patent of the united states, no. , , for an improvement in metallic railroad-ties, were granted to the party of the first part january , ; and whereas the party of the second part is desirous of manufacturing metallic railroad-ties containing the said patented improvements: _now, therefore_, the parties hereto have agreed as follows: i. the party of the first part hereby licenses and empowers the party of the second part to manufacture, subject to the conditions herein named, at their plant in chicago, and in no other place or places, to the end of the term for which said letters patent were granted, metallic railroad-ties containing the patented improvements, and to sell the same within the united states. ii. the party of the second part agrees to make full and true returns to the party of the first part, under oath, upon the first days of january and july in each year, of all metallic railroad-ties containing said patented improvements manufactured by them. iii. the party of the second part agrees to pay the party of the first part five dollars as a license fee upon each and every thousand metallic railroad-ties manufactured by the party of the second part containing the patented improvements: provided, that if the said fee be paid upon the days provided herein for semi-annual returns, or within ten days thereafter, a discount of fifty per cent, shall be made from said fee for prompt payment. iv. the party of the second part agrees to put forth their best efforts and use due diligence in the manufacture and sale of the metallic railroad-ties containing the said patented improvements, and if the royalties do not amount to five hundred dollars semi-annually, the party of the first part may terminate this license by serving a written notice upon the party of the second part. v. upon the failure of the party of the second part to make returns or to make payment of license fees, as herein provided, for thirty days after the days herein named, the party of the first part may terminate this license by serving a written notice upon the party of the second part; but the party of the second part shall not thereby be discharged from any liability to the party of the first part for any license fees due at the time of the service of such notice. _in witness whereof_, the parties above named have hereto set their hands the day and year first above written, at chicago, county of cook, and state of illinois. richard doe, _metallic railway tie company_, per john roe, president. license:--exclusive--with royalty _this agreement_, made this tenth day of january, , between richard doe, of boston, state of massachusetts, party of the first part, and the roe vending machine company, a corporate body under the laws of the state of new jersey, located and doing business at the city of new york, in the state of new york, party of the second part, _witnesseth_, that whereas, letters patent of the united states, no. , , were, on the first day of january, , granted to the said party of the first part, for improvements in coin-controlled machines, and whereas said party of the second part is desirous of manufacturing and selling said patented article: now, therefore, the parties hereto have agreed as follows: i. the party of the first part gives to the party of the second part the exclusive right to manufacture and sell the said patented improvements, to the end of the term of said patent, subject to the conditions hereinafter named. ii. the party of the second part agrees to make full and true returns, on the first days of january and july in each year, of all machines manufactured and sold by them containing the said patented improvements in the six calendar months next preceding the date of any such notice; and if the party of the first part shall not be satisfied in any respect with any such return, then shall the party of the first part have the right, either by himself or by his attorney, to examine any and all books of account of said party of the second part concerning any items, charges, memoranda, or information relating to the manufacture or sale of said patented coin-controlled machines; and upon request made, said party of the second part shall produce all such books for said examination. iii. the party of the second part agrees to pay the party of the first part five dollars as a license fee upon every one of the said patented coin-controlled machines manufactured by them, the whole of said license fee for each term of six months to be due and payable on the days hereinabove provided for semi-annual returns; provided, that if said fee be paid upon the days herein provided, or within fifteen days thereafter, a discount of fifty per cent, shall be made from said fee for prompt payment. iv. the party of the second part agrees to pay the party of the first part at least two thousand dollars, less discount, as said license fee upon each of the semi-annual terms, even though they should not make enough of said patented machines to amount to that sum at the regular royalty of five dollars each. v. the party of the second part shall cast, or otherwise permanently place, upon every such machine made under this license the word "doe," and in close relation thereto the word "patented," and the number and date of said patent. vi. the party of the second part shall not, during the life of this license, make or sell any article which can compete in the market with said coin-controlled machines. vii. upon the failure of the party of the second part to keep each and all of the conditions of this license and agreement, the party of the first part may, at his option, terminate this license, and such termination shall not release said party of the second part from any liability due at such time to the party of the first part. _in witness whereof_, the above-named parties (the said roe vending machine company, by its president) have hereto set their hands the day and year first above written, richard doe, _roe vending machine company_, by john roe, president. no general legal forms should be relied upon too implicitly as suiting particular cases, and an inventor, in order to fully protect his interests, should consult a reliable patent attorney, and have the forms properly prepared to suit his individual case. [illustration: map of continental usa] chapter x tables and statistics official census of the united states, by counties, for (_from the bulletin of the director of the census_) alabama.--area, , square miles. autauga , | dallas , | marengo , baldwin , | dekalb , | marion , barbour , | | marshall , bibb , | elmore , | mobile , blount , | escambia , | monroe , | etowah , | bullock , | fayette , | montgomery , butler , | franklin , | morgan , calhoun , | | perry , chambers , | geneva , | pickens , cherokee , | greene , | pike , | hale , | chilton , | henry , | randolph , choctaw , | houston , | russell , clarke , | | st. clair , clay , | jackson , | shelby , cleburne , | jefferson , | sumter , | lamar , | coffee , | lauderdale , | talladega , colbert , | lawrence , | tallapoosa , conecuh , | | tuscaloosa , coosa , | lee , | walker , covington , | limestone , | washington , | lowndes , | crenshaw , | macon , | wilcox , cullman , | madison , | winston , dale , | | total , , arizona.--area, , square miles. apache , | maricopa , | santa cruz , cochise , | mohave , | yavapai , coconino , | navajo , | yuma , gila , | pima , | graham , | pinal , | total , arkansas.--area, , square miles. arkansas , | garland , | newton , ashley , | grant , | ouachita , baxter , | greene , | perry , benton , | hempstead , | phillips , boone , | hot spring , | pike , | | bradley , | howard , | poinsett , calhoun , | independence , | polk , carroll , | izard , | pope , chicot , | jackson , | prairie , clark , | jefferson , | pulaski , | | clay , | johnson , | randolph , cleburne , | lafayette , | st. francis , cleveland , | lawrence , | saline , columbia , | lee , | scott , conway , | lincoln , | searcy , | | craighead , | little river , | sebastian , crawford , | logan , | sevier , crittenden , | lonoke , | sharp , cross , | madison , | stone , dallas , | marion , | union , | | desha , | miller , | van buren , drew , | mississippi , | washington , faulkner , | monroe , | white , franklin , | montgomery , | woodruff , fulton , | nevada , | yell , total , , california.--area, , square miles. alameda , | glenn , | marin , alpine | humboldt , | mariposa , amador , | imperial , | mendocino , butte , | inyo , | merced , calaveras , | kern , | modoc , | | colusa , | kings , | mono , contra costa , | lake , | monterey , del norte , | lassen , | napa , eldorado , | los angeles , | nevada , fresno , | madera , | orange , | | placer , | san mateo , | sutter , plumas , | santa barbara , | tehama , riverside , | santa clara , | trinity , sacramento , | santa cruz , | tulare , san benito , | shasta , | tuolumne , | | san bernadino , | sierra , | ventura , san diego , | siskiyou , | yolo , san francisco , | solano , | yuba , san joaquin , | sonoma , | san luis obispo , | stanislaus , | total , , colorado.--area, , square miles. adams , | garfield , | morgan , arapahoe , | gilpin , | otero , archuleta , | grand , | ouray , baca , | gunnison , | park , bent , | hinsdale | phillips , | | boulder , | huerfano , | pitkin , chaffee , | jackson , | prowers , cheyenne , | jefferson , | pueblo , clear creek , | kiowa , | rio blanco , conejos , | kit carson , | rio grande , | | costilla , | la plate , | routt , custer , | lake , | saguache , delta , | larimer , | san juan , denver , | las animas , | san miguel , dolores | lincoln , | sedgwick , | | douglas , | logan , | summit , eagle , | mesa , | teller , el paso , | mineral , | washington , elbert , | montezuma , | weld , fremont , | montrose , | yuma , total , connecticut.--area, , square miles. fairfield , | middlesex , | new london , hartford , | | tolland , litchfield , | new haven , | windham , total , , delaware.--area, , square miles. kent , | newcastle , | sussex , total , district of columbia.--area, square miles. the district , florida.--area, , square miles. alachua , | hillsboro , | osceola , baker , | holmes , | palm beach , bradford , | jackson , | pasco , brevard , | jefferson , | calhoun , | | polk , | lafayette , | putnam , citrus , | lake , | st. john , clay , | lee , | st. lucie , columbia , | leon , | santa rosa , dade , | levy , | de soto , | | sumter , | liberty , | suwanee , duval , | madison , | taylor , escambia , | manatee , | volusia , franklin , | marion , | wakulla , gadsden , | monroe , | hamilton , | | walton , | nassau , | washington , hernando , | orange , | total , georgia.--area, , square miles. appling , | clayton , | forsyth , baker , | clinch , | franklin , baldwin , | cobb , | fulton , banks , | coffee , | gilmer , bartow , | colquitt , | glascock , | | ben hill , | columbia , | glynn , berrien , | coweta , | gordon , bibb , | crawford , | grady , brooks , | crisp , | greene , bryan , | dade , | gwinnett , | | bulloch , | dawson , | habersham , burke , | decatur , | hall , butts , | dekalb , | hancock , calhoun , | dodge , | haralson , camden , | dooly , | harris , | | campbell , | dougherty , | hart , carroll , | douglas , | heard , catoosa , | early , | henry , charlton , | echols , | houston , chatham , | effingham , | irwin , | | chattahoochee , | elbert , | jackson , chattooga , | emanuel , | jasper , cherokee , | fannin , | jeff davis , clarke , | fayette , | jefferson , clay , | floyd , | jenkins , | | johnson , | paulding , | tift , jones , | pickens , | toombs , laurens , | pierce , | towns , lee , | pike , | troup , liberty , | polk , | turner , | | lincoln , | pulaski , | twiggs , lowndes , | putnam , | union , lumpkin , | quitman , | upson , mcduffie , | rabun , | walker , mcintosh , | randolph , | walton , | | macon , | richmond , | ware , madison , | rockdale , | warren , marion , | schley , | washington , meriwether , | screven , | wayne , miller , | spalding , | webster , | | milton , | stephens , | white , mitchell , | stewart , | whitfield , monroe , | sumter , | wilcox , montgomery , | talbot , | wilkes , morgan , | taliaferro , | wilkinson , | | murray , | tattnall , | worth , muscogee , | taylor , | newton , | telfair , | oconee , | terrell , | oglethorpe , | thomas , | total , , idaho.--area, , square miles. ada , | cassia , | lemhi , bannock , | custer , | lincoln , bear lake , | | nez perce , bingham , | elmore , | oneida , blaine , | fremont , | owyhee , | idaho , | boise , | kootenai , | shoshone , bonner , | latah , | twin falls , canyon , | | washington , total , illinois.--area, , square miles. adams , | christian , | douglas , alexander , | clark , | dupage , bond , | clay , | edgar , boone , | clinton , | edwards , brown , | coles , | effingham , | | bureau , | cook , , | fayette , calhoun , | crawford , | ford , carroll , | cumberland , | franklin , cass , | dekalb , | fulton , champaign , | dewitt , | gallatin , | | greene , | mchenry , | rock island , grundy , | mclean , | st. clair , hamilton , | macon , | saline , hancock , | macoupin , | sangamon , hardin , | madison[*] , | schuyler , | | henderson , | marion , | scott , henry , | marshall , | shelby , iroquois , | mason , | stark , jackson , | massac , | stephenson , jasper , | menard , | tazewell , | | jefferson , | mercer , | union , jersey , | monroe , | vermilion , jo daviess , | montgomery , | wabash , johnson , | morgan , | warren , kane , | moultrie , | washington , | | kankakee , | ogle , | wayne , kendall , | peoria , | white , knox , | perry , | whiteside , lake , | platt , | will , lasalle , | pike , | williamson , | | lawrence , | pope , | winnebago , lee , | pulaski , | woodford , livingston , | putnam , | logan , | randolph , | mcdonough , | richland , | total , , indiana.--area, , square miles. adams , | fayette , | johnson , allen , | floyd , | knox , bartholomew , | fountain , | kosciusko , benton , | franklin , | lagrange , blackford , | fulton , | lake , | | boone , | gibson , | laporte , brown , | grant , | lawrence , carroll , | greene , | madison , cass , | hamilton , | marion , clark , | hancock , | marshall , | | clay , | harrison , | martin , clinton , | hendricks , | miami , crawford , | henry , | monroe , daviess , | howard , | montgomery , dearborn , | huntington , | morgan , | | decatur , | jackson , | newton , dekalb , | jasper , | noble , delaware , | jay , | ohio , dubois , | jefferson , | orange , elkhart , | jennings , | owen , | | parke , | scott , | vermilion , perry , | shelby , | vigo , pike , | spencer , | wabash , porter , | starke , | posey , | | warren , | steuben , | warrick , pulaski , | sullivan , | washington , putnam , | switzerland , | wayne , randolph , | tippecanoe , | wells , ripley , | tipton , | rush , | | white , | union , | whitley , st. joseph , | vanderburg , | total , , iowa.--area, , square miles. adair , | franklin , | monroe , adams , | | montgomery , allamakee , | fremont , | muscatine , appanoose , | greene , | audubon , | grundy , | o'brien , | guthrie , | osceola , benton , | hamilton , | page , blackhawk , | | palo alto , boone , | hancock , | plymouth , bremer , | hardin , | buchanan , | harrison , | pocahontas , | henry , | polk , buena vista , | howard , | pottawattamie , butler , | | poweshiek , calhoun , | humboldt , | ringgold , carroll , | ida , | cass , | iowa , | sac , | jackson , | scott , cedar , | jasper , | shelby , cerro gordo , | | sioux , cherokee , | jefferson , | story , chickasaw , | johnson , | clarke , | jones , | tama , | keokuk , | taylor , clay , | kossuth , | union , clayton , | | van buren , clinton , | lee , | wapello , crawford , | linn , | dallas , | louisa , | warren , | lucas , | washington , davis , | lyon , | wayne , decatur , | | webster , delaware , | madison , | winnebago , des moines , | mahaska , | dickinson , | marion , | winneshiek , | marshall , | woodbury , dubuque , | mills , | worth , emmet , | | wright , fayette , | mitchell , | floyd , | monona , | total , , kansas.--area, , square miles. allen , | greeley , | osborne , anderson , | greenwood , | ottawa , atchison , | hamilton , | pawnee , barber , | harper , | phillips , barton , | harvey , | pottawatomie , | | bourbon , | haskell | pratt , brown , | hodgeman , | rawlins , butler , | jackson , | reno , chase , | jefferson , | republic , chautauqua , | jewell , | rice , | | cherokee , | johnson , | riley , cheyenne , | kearny , | rooks , clark , | kingman , | rush , clay , | kiowa , | russell , cloud , | labette , | saline , | | coffey , | lane , | scott , comanche , | leavenworth , | sedgwick , cowley , | lincoln , | seward , crawford , | linn , | shawnee , decatur , | logan , | sheridan , | | dickinson , | lyon , | sherman , doniphan , | mcpherson , | smith , douglas , | marion , | stafford , edwards , | marshall , | stanton , elk , | meade , | stevens , | | ellis , | miami , | sumner , ellsworth , | mitchell , | thomas , finney , | montgomery , | trego , ford , | morris , | wabaunsee , franklin , | morton , | wallace , | | geary , | nemaha , | washington , gove , | neosho , | wichita , graham , | ness , | wilson , grant , | norton , | woodson , gray , | osage , | wyandotte , total , , kentucky.--area, , square miles. adair , | boyle , | carroll , allen , | bracken , | carter , anderson , | breathitt , | casey , ballard , | breckinridge , | christian , barren , | bullitt , | clark , | | bath , | butler , | clay , bell , | caldwell , | clinton , boone , | calloway , | crittenden , bourbon , | campbell , | cumberland , boyd , | carlisle , | daviess , | | edmonson , | knox , | ohio , elliott , | larue , | oldham , estill , | laurel , | owen , fayette , | lawrence , | owsley , fleming , | lee , | pendleton , | | floyd , | leslie , | perry , franklin , | letcher , | pike , fulton , | lewis , | powell , gallatin , | lincoln , | pulaski , garrard , | livingston , | robertson , | | grant , | logan , | rockcastle , graves , | lyon , | rowan , grayson , | mccracken , | russell , green , | mclean , | scott , greenup , | madison , | shelby , | | hancock , | magoffin , | simpson , hardin , | marion , | spencer , harlan , | marshall , | taylor , harrison , | martin , | todd , hart , | mason , | trigg , | | henderson , | meade , | trimble , henry , | menifee , | union , hickman , | mercer , | warren , hopkins , | metcalfe , | washington , jackson , | monroe , | wayne , | | jefferson , | montgomery , | webster , jessamine , | morgan , | whitley , johnson , | muhlenberg , | wolfe , kenton , | nelson , | woodford , knott , | nicholas , | total , , louisiana.--area, , square miles. acadia , | east carroll , | natchitoches , ascension , | east feliciana , | orleans , assumption , | franklin , | ouachita , avoyelles , | grant , | plaquemines , bienville , | iberia , | pointe coupee , | | bossier , | iberville , | rapides , caddo , | jackson , | red river , calcasieu , | jefferson , | richland , caldwell , | la salle , | sabine , cameron , | lafayette , | st. bernard , | | catahoula , | lafourche , | st. charles , claiborne , | lincoln , | st. helena , concordia , | livingston , | st. james , de soto , | madison , | st. john the east baton rouge , | morehouse , | baptist , | | st. landry , | | st. martin , | terrebonne , | webster , st. mary , | union , | west baton rouge , st. tammany , | vermilion , | west carroll , tangipahoa , | vernon , | west feliciana , tensas , | washington , | winn , total , , maine.--area, , square miles. androscoggin , | kennebec , | piscataquis , aroostook , | knox , | sagadahoc , cumberland , | lincoln , | somerset , franklin , | oxford , | waldo , hancock , | penobscot , | washington , | | york , total , maryland.--area, , square miles. allegany , | charles , | prince georges , anne arundel , | dorchester , | queen annes , baltimore , | | st. marys , baltimore city , | frederick , | somerset , calvert , | garrett , | | hartford , | talbot , caroline , | howard , | washington , carroll , | kent , | wicomico , cecil , | | worcester , total , , massachusetts.--area, , square miles. barnstable , | franklin , | norfolk , berkshire , | hampden , | plymouth , bristol , | hampshire , | suffolk , dukes , | middlesex , | worcester , essex , | nantucket , | total , , michigan.--area, , square miles. alcona , | berrien , | delta , alger , | branch , | dickinson , allegan , | calhoun , | eaton , alpena , | cass , | emmet , antrim , | charlevoix , | genesee , | | arenac , | cheboygan , | gladwin , baraga , | chippewa , | gogebic , barry , | clare , | grand traverse , bay , | clinton , | gratiot , benzie , | crawford , | hillsdale , | | houghton , | mackinac , | ontonagon , huron , | macomb , | osceola , ingham , | | oscoda , ionia , | manistee , | otsego , iosco , | marquette , | ottawa , | mason , | iron , | mecosta , | presque isle , isabella , | menominee , | roscommon , jackson , | | saginaw , kalamazoo , | midland , | st. clair , kalkaska , | missaukee , | st. joseph , | monroe , | kent , | montcalm , | sanilac , keweenaw , | montmorency , | schoolcraft , lake , | | shiawassee , lapeer , | muskegon , | tuscola , leelanau , | newaygo , | van buren , | oakland , | lenawee , | oceana , | washtenaw , livingston , | ogemaw , | wayne , luce , | | wexford , total , , minnesota.--area, , square miles. aitkin , | isanti , | polk , anoka , | | pope , becker , | itasca , | ramsey , beltrami , | jackson , | benton , | kanabec , | red lake , | kandiyohi , | redwood , bigstone , | kittson , | renville , blue earth , | | rice , brown , | koochiching , | rock , carlton , | lac qui parle , | carver , | lake , | roseau , | le sueur , | st. louis , cass , | lincoln , | scott , chippewa , | | sheburne , chisago , | lyon , | sibley , clay , | mcleod , | clearwater , | mahnomen , | stearns , | marshall , | steele , cook , | martin , | stevens , cottonwood , | | swift , crow wing , | meeker , | todd , dakota , | mille lacs , | dodge , | morrison , | traverse , | mower , | wabasha , douglas , | murray , | wadena , faribault , | | waseca , fillmore , | nicollet , | washington , freeborn , | nobles , | goodhue , | norman , | watonwan , | olmsted , | wilkin , grant , | otter tail , | winona , hennepin , | | wright , houston , | pine , | yellow medicine , hubbard , | pipestone , | total , , mississippi.--area, , square miles. adams , | itawamba , | pearl river , alcorn , | jackson , | perry , amite , | jasper , | attala , | | pike , benton , | jefferson , | pontotoc , | jefferson davis , | prentiss , bolivar , | jones , | quitman , calhoun , | kemper , | rankin , carroll , | lafayette , | chickasaw , | | scott , choctaw , | lamar , | sharkey , | lauderdale , | simpson , claiborne , | lawrence , | smith , clarke , | leake , | sunflower , clay , | lee , | coahoma , | | tallahatchie , copiah , | leflore , | tate , | lincoln , | tippah , covington , | lowndes , | tishomingo , de soto , | madison , | tunica , forrest , | marion , | franklin , | | union , george , | marshall , | warren , | monroe , | washington , greene , | montgomery , | wayne , grenada , | neshoba , | webster , hancock , | newton , | harrison , | | wilkinson , hinds , | noxubee , | winston , | oktibbeha , | yalobusha , holmes , | panola , | yazoo , issaquena , | | total , , missouri.--area, , square miles. adair , | cape girardeau , | daviess , andrew , | carroll , | dekalb , atchison , | carter , | dent , audrain , | cass , | douglas , barry , | cedar , | dunklin , | | barton , | chariton , | franklin , bates , | christian , | gasconade , benton , | clark , | gentry , bollinger , | clay , | greene , boone , | clinton , | grundy , | | buchanan , | cole , | harrison , butler , | cooper , | henry , caldwell , | crawford , | hickory , callaway , | dade , | holt , camden , | dallas , | howard , | | howell , | montgomery , | st. clair , iron , | | st. francois , jackson , | morgan , | st. louis , jasper , | new madrid , | jefferson , | newton , | st. louis city , | nodaway , | ste. genevieve , johnson , | oregon , | saline , knox , | | schuyler , laclede , | osage , | scotland , lafayette , | ozark , | lawrence , | pemiscot , | scott , | perry , | shannon , lewis , | pettis , | shelby , lincoln , | | stoddard , linn , | phelps , | stone , livingston , | pike , | mcdonald , | platte , | sullivan , | polk , | taney , macon , | pulaski , | texas , madison , | | vernon , maries , | putnam , | warren , marion , | ralls , | mercer , | randolph , | washington , | ray , | wayne , miller , | reynolds , | webster , mississippi , | | worth , moniteau , | ripley , | wright , monroe , | st. charles , | total , , montana.--area, , square miles. beaverhead , | gallatin , | powell , broadwater , | granite , | ravalli , carbon , | jefferson , | rosebud , cascade , | lewis and clark , | sanders , chouteau , | lincoln , | silver bow , | | sweet grass , custer , | madison , | dawson , | meagher , | teton , deer lodge , | missoula , | valley , fergus , | park , | yellowstone , flathead , | | total , nebraska.--area, , square miles. adams , | butler , | dakota , antelope , | cass , | dawes , banner , | cedar , | dawson , blaine , | chase , | deuel , boone , | cherry , | dixon , | | boxbutte , | cheyenne , | dodge , boyd , | clay , | douglas , brown , | colfax , | dundy , buffalo , | cuming , | fillmore , burt , | custer , | franklin , | | frontier , | kimball , | richardson , furnas , | knox , | rock , gage , | lancaster , | saline , garden , | lincoln , | garfield , | | sarpy , | logan , | saunders , gosper , | loup , | scotts bluff , grant , | mcpherson , | seward , greeley , | madison , | sheridan , hall , | merrick , | hamilton , | | sherman , | morrill , | sioux , harlan , | nance , | stanton , hayes , | nemaha , | thayer , hitchcock , | nuckolls , | thomas , holt , | otoe , | hooker | | thurston , | pawnee , | valley , howard , | perkins , | washington , jefferson , | phelps , | wayne , johnson , | pierce , | webster , kearney , | platte , | keith , | | wheeler , | polk , | york , keyapaha , | redwillow , | total , , nevada.--area, , square miles. churchill , | eureka , | nye , clark , | humboldt , | ormsby , douglas , | lander , | storey , elko , | lincoln , | washoe , esmeralda , | lyon , | white pine , total , new hampshire.--area, , square miles. belknap , | grafton , | rockingham , carroll , | | strafford , cheshire , | hillsboro , | sullivan , coos , | merrimack , | total , new jersey.--area, , square miles. atlantic , | hudson , | passaic , bergen , | hunterdon , | salem , burlington , | | somerset , camden , | mercer , | sussex , cape may , | middlesex , | union , | monmouth , | cumberland , | morris , | warren , essex , | ocean , | gloucester , | | total , , new mexico.--area, , square miles. bernalillo , | luna , | sandoval , chaves , | | santa fe , colfax , | mckinley , | curry , | mora , | sierra , dona ana , | otero , | socorro , | quay , | taos , eddy , | rio arriba , | torrance , grant , | | union , guadalupe , | roosevelt , | lincoln , | san juan , | valencia , | san miguel , | total , new york.--area, , square miles. albany , | herkimer , | rensselaer , allegany , | jefferson , | richmond , broome , | kings , , | rockland , cattaraugus , | lewis , | st. lawrence , cayuga , | livingston , | saratoga , | | chautauqua , | madison , | schenectady , chemung , | monroe , | schoharie , chenango , | montgomery , | schuyler , clinton , | nassau , | seneca , columbia , | new york , , | steuben , | | cortland , | niagara , | suffolk , delaware , | oneida , | sullivan , dutchess , | onondaga , | tioga , erie , | ontario , | tompkins , essex , | orange , | ulster , | | franklin , | orleans , | warren , fulton , | oswego , | washington , genesee , | otsego , | wayne , greene , | putnam , | westchester , hamilton , | queens , | wyoming , | | | | yates , total , , north carolina.--area, , square miles. alamance , | burke , | clay , alexander , | cabarrus , | cleveland , alleghany , | caldwell , | columbus , anson , | camden , | craven , ashe , | carteret , | cumberland , | | beaufort , | caswell , | currituck , bertie , | catawba , | dare , bladen , | chatham , | davidson , brunswick , | cherokee , | davie , buncombe , | chowan , | duplin , | | durham , | lincoln , | robeson , edgecombe , | mcdowell , | rockingham , forsyth , | macon , | rowan , franklin , | | rutherford , gaston , | madison , | sampson , | martin , | gates , | mecklenburg , | scotland , graham , | mitchell , | stanly , granville , | montgomery , | stokes , greene , | | surry , guilford , | moore , | swain , | nash , | halifax , | new hanover , | transylvania , harnett , | northampton , | tyrrell , haywood , | onslow , | union , henderson , | | vance , hertford , | orange , | wake , | pamlico , | hyde , | pasquotank , | warren , iredell , | pender , | washington , jackson , | perquimans , | watauga , johnston , | | wayne , jones , | person , | wilkes , | pitt , | lee , | polk , | wilson , lenoir , | randolph , | yadkin , | richmond , | yancey , total , , north dakota.--area, , square miles. adams , | griggs , | pierce , barnes , | hettinger , | ramsey , benson , | kidder , | ransom , billings , | lamoure , | richland , bottineau , | logan , | rolette , | | bowman , | mchenry , | sargent , burleigh , | mcintosh , | sheridan , cass , | mckenzie , | stark , cavalier , | mclean , | steele , dickey , | mercer , | stutsman , | | dunn , | mountrail , | towner , eddy , | morton , | traill , emmons , | nelson , | walsh , foster , | oliver , | ward , grand forks , | pembina , | wells , | | | | williams , total , ohio.--area, , square miles. adams , | auglaize , | champaign , allen , | belmont , | clark , ashland , | brown , | clermont , ashtabula , | butler , | clinton , athens , | carroll , | columbiana , | | coshocton , | jefferson , | pike , crawford , | knox , | portage , cuyahoga , | lake , | preble , darke , | lawrence , | putnam , defiance , | licking , | richland , | | delaware , | logan , | ross , erie , | lorain , | sandusky , fairfield , | lucas , | scioto , fayette , | madison , | seneca , franklin , | mahoning , | shelby , | | fulton , | marion , | stark , gallia , | medina , | summit , geauga , | meigs , | trumbull , greene , | mercer , | tuscarawas , guernsey , | miami , | union , | | hamilton , | monroe , | van wert , hancock , | montgomery , | vinton , hardin , | morgan , | warren , harrison , | morrow , | washington , henry , | muskingum , | wayne , | | highland , | noble , | williams , hocking , | ottawa , | wood , holmes , | paulding , | wyandot , huron , | perry , | jackson , | pickaway , | total , , oklahoma.--area, , square miles. adair , | dewey , | logan , alfalfa , | ellis , | love , atoka , | garfield , | mcclain , beaver , | garvin , | mccurtain , beckham , | grady , | mcintosh , | | blaine , | grant , | major , bryan , | greer , | marshall , caddo , | harmon , | mayes , canadian , | harper , | murray , carter , | haskell , | muskogee , | | cherokee , | hughes , | noble , choctaw , | jackson , | nowata , cimarron , | jefferson , | okfuskee , cleveland , | johnston , | oklahoma , coal , | kay , | okmulgee , | | comanche , | kingfisher , | osage , craig , | kiowa , | ottawa , creek , | latimer , | pawnee , custer , | le flore , | payne , delaware , | lincoln , | pittsburg , | | pontotoc , | seminole , | tulsa , pottawatomie , | sequoyah , | wagoner , pushmataha , | stephens , | washington , roger mills , | texas , | washita , rogers , | tillman , | woods , | | | | woodward , total , , oregon.--area, , square miles. baker , | hood river , | multnomah , benton , | jackson , | polk , clackamas , | josephine , | clatsop , | | sherman , columbia , | klamath , | tillamook , | lake , | umatilla , coos , | lane , | union , crook , | lincoln , | wallowa , curry , | linn , | douglas , | | wasco , gilliam , | malheur , | washington , | marion , | wheeler , grant , | morrow , | yamhill , harney , | | total , pennsylvania.--area, , square miles. adams , | erie , | northampton , allegheny , , | | northumberland , armstrong , | fayette , | perry , beaver , | forest , | bedford , | franklin , | philadelphia , , | fulton , | pike , berks , | greene , | potter , blair , | | schuylkill , bradford , | huntingdon , | snyder , bucks , | indiana , | butler , | jefferson , | somerset , | juniata , | sullivan , cambria , | lackawanna , | susquehanna , cameron , | | tioga , carbon , | lancaster , | union , center , | lawrence , | chester , | lebanon , | venango , | lehigh , | warren , clarion , | luzerne , | washington , clearfield , | | wayne , clinton , | lycoming , | westmoreland , columbia , | mckean , | crawford , | mercer , | wyoming , | mifflin , | york , cumberland , | monroe , | dauphin , | | delaware , | montgomery , | elk , | montour , | total , , rhode island.--area, , square miles. bristol , | newport , | washington , kent , | providence , | total , south carolina.--area, , square miles. abbeville , | dillon , | marion , aiken , | dorchester , | marlboro , anderson , | edgefield , | newberry , bamberg , | fairfield , | oconee , barnwell , | florence , | orangeburg , | | beaufort , | georgetown , | pickens , berkeley , | greenville , | richland , calhoun , | greenwood , | saluda , charleston , | hampton , | spartanburg , cherokee , | horry , | sumter , | | chester , | kershaw , | union , chesterfield , | lancaster , | williamsburg , clarendon , | laurens , | york , colleton , | lee , | darlington , | lexington , | total , , south dakota.--area, , square miles. armstrong | fall river , | minnehaha , aurora , | faulk , | beadle , | grant , | moody , bonhomme , | | pennington , brookings , | gregory , | perkins , | hamlin , | potter , brown , | hand , | roberts , brule , | hanson , | buffalo , | harding , | sanborn , butte , | | schnasse campbell , | hughes , | spink , | hutchinson , | stanley , charles mix , | hyde , | sterling clark , | jerauld , | clay , | kingsbury , | sully , codington , | | tripp , corson , | lake , | turner , | lawrence , | union , custer , | lincoln , | walworth , davison , | lyman , | day , | mccook , | yankton , deuel , | | pine ridge indian dewey , | mcpherson , | reservation , | marshall , | rosebud indian douglas , | meade , | reservation , edmunds , | miner , | total , tennessee.--area, , square miles. anderson , | hancock , | morgan , bedford , | hardeman , | obion , benton , | | overton , bledsoe , | hardin , | perry , blount , | hawkins , | pickett , | haywood , | bradley , | henderson , | polk , campbell , | henry , | putnam , cannon , | | rhea , carroll , | hickman , | roane , carter , | houston , | robertson , | humphreys , | cheatham , | jackson , | rutherford , chester , | james , | scott , claiborne , | | sequatchie , clay , | jefferson , | sevier , cocke , | johnson , | shelby , | knox , | coffee , | lake , | smith , crockett , | lauderdale , | stewart , cumberland , | | sullivan , davidson , | lawrence , | sumner , decatur , | lewis , | tipton , | lincoln , | dekalb , | loudon , | trousdale , dickson , | mcminn , | unicoi , dyer , | | union , fayette , | mcnairy , | van buren , fentress , | macon , | warren , | madison , | franklin , | marion , | washington , gibson , | marshall , | wayne , giles , | | weakley , grainger , | maury , | white , greene , | meigs , | williamson , | monroe , | grundy , | montgomery , | wilson , hamblen , | moore , | hamilton , | | total , , texas.--area, , square miles. anderson , | bastrop , | brazos , andrews | baylor , | brewster , angelina , | bee , | briscoe , aransas , | bell , | brown , archer , | bexar , | burleson , | | armstrong , | blanco , | burnet , atascosa , | borden , | caldwell , austin , | bosque , | calhoun , bailey | bowie , | callahan , bandera , | brazoria , | cameron , | | camp , | gaines , | knox , carson , | galveston , | la salle , cass , | garza , | lamar , castro , | gillespie , | lamb chambers , | glasscock , | lampasas , | | cherokee , | goliad , | lavaca , childress , | gonzales , | lee , clay , | gray , | leon , cochran | grayson , | liberty , coke , | gregg , | limestone , | | coleman , | grimes , | lipscomb , collin , | guadalupe , | live oak , collingsworth , | hale , | llano , colorado , | hall , | loving comal , | hamilton , | lubbock , | | comanche , | hansford | lynn , concho , | hardeman , | mcculloch , cooke , | hardin , | mclennan , coryell , | harris , | mcmullen , cottle , | harrison , | madison , | | crane | hartley , | marion , crockett , | haskell , | martin , crosby , | hays , | mason , dallam , | hemphill , | matagorda , dallas , | henderson , | maverick , | | dawson , | hidalgo , | medina , de witt , | hill , | menard , deaf smith , | hockley | midland , delta , | hood , | milam , denton , | hopkins , | mills , | | dickens , | houston , | mitchell , dimmit , | howard , | montague , donley , | hunt , | montgomery , duval , | hutchinson | moore eastland , | irion , | morris , | | ector , | jack , | motley , edwards , | jackson , | nacogdoches , el paso , | jasper , | navarro , ellis , | jeff davis , | newton , erath , | jefferson , | nolan , | | falls , | johnson , | nueces , fannin , | jones , | ochiltree , fayette , | karnes , | oldham fisher , | kaufman , | orange , floyd , | kendall , | palo pinto , | | foard , | kent , | panola , fort bend , | kerr , | parker , franklin , | kimble , | parmer , freestone , | king | pecos , frio , | kinney , | polk , | | potter , | sherman , | val verde , presidio , | smith , | rains , | somervell , | van zandt , randall , | | victoria , reagan | starr , | walker , | stephens , | waller , red river , | sterling , | ward , reeves , | stonewall , | refugio , | sutton , | washington , roberts | | webb , robertson , | swisher , | wharton , | tarrant , | wheeler , rockwall , | taylor , | wichita , runnels , | terrell , | rusk , | terry , | wilbarger , sabine , | | williamson , san augustine , | throckmorton , | wilson , | titus , | winkler san jacinto , | tom green , | wise , san patricio , | travis , | san saba , | trinity , | wood , schleicher , | | yoakum scurry , | tyler , | young , | upshur , | zapata , shackelford , | upton | zavalla , shelby , | uvalde , | total , , utah.--area, , square miles. beaver , | kane , | tooele , boxelder , | millard , | uinta , cache , | morgan , | utah , carbon , | piute , | wasatch , davis , | rich , | washington , | | emery , | salt lake , | wayne , garfield , | san juan , | weber , grand , | sanpete , | iron , | sevier , | juab , | summit , | total , vermont.--area, , square miles. addison , | franklin , | rutland , bennington , | grand isle , | washington , caledonia , | lamoille , | windham , chittenden , | orange , | windsor , essex , | orleans , | total , virginia.--area, , square miles. accomac , | amherst , | bland , albemarle , | appomattox , | botetourt , alexandria , | augusta , | brunswick , alleghany , | bath , | buchanan , amelia , | bedford , | buckingham , | | campbell , | highland , | prince edward , caroline , | isle of wight , | prince george , carroll , | james city , | charles city , | king and queen , | prince william , charlotte , | king george , | princess anne , | | pulaski , chesterfield , | king william , | rappahannock , clarke , | lancaster , | richmond , craig , | lee , | culpeper , | loudoun , | roanoke , cumberland , | louisa , | rockbridge , | | rockingham , dickenson , | lunenburg , | russell , dinwiddie , | madison , | scott , elizabeth city , | mathews , | essex , | mecklenburg , | shenandoah , fairfax , | middlesex , | smyth , | | southampton , fauquier , | montgomery , | spotsylvania , floyd , | nansemond , | stafford , fluvanna , | nelson , | franklin , | new kent , | surry , frederick , | norfolk , | sussex , | | tazewell , giles , | northampton , | warren , gloucester , | northumberland , | warwick , goochland , | nottoway , | grayson , | orange , | washington , greene , | page , | westmoreland , | | wise , greenesville , | patrick , | wythe , halifax , | pittsylvania , | york , hanover , | powhatan , | henrico , | | henry , | | total , , washington.--area, , square miles. adams , | grant , | pierce , asotin , | island , | san juan , benton , | | skagit , chehalis , | jefferson , | skamania , chelan , | king , | snohomish , | kitsap , | clallam , | kittitas , | spokane , clarke , | klickitat , | stevens , columbia , | | thurston , cowlitz , | lewis , | wahkiakum , douglas , | lincoln , | walla walla , | mason , | ferry , | okanogan , | whatcom , franklin , | pacific , | whitman , garfield , | | yakima , total , , west virginia.--area, , square miles. barbour , | kanawha , | pocahontas , berkeley , | | preston , boone , | lewis , | putnam , braxton , | lincoln , | brooke , | logan , | raleigh , | mcdowell , | randolph , cabell , | marion , | ritchie , calhoun , | | roane , clay , | marshall , | summers , doddridge , | mason , | fayette , | mercer , | taylor , | mineral , | tucker , gilmer , | mingo , | tyler , grant , | | upshur , greenbrier , | monongalia , | wayne , hampshire , | monroe , | hancock , | morgan , | webster , | nicholas , | wetzel , hardy , | ohio , | wirt , harrison , | | wood , jackson , | pendleton , | wyoming , jefferson , | pleasants , | total , , wisconsin.--area, , square miles. adams , | iowa , | polk , ashland , | | portage , barron , | iron , | price , bayfield , | jackson , | brown , | jefferson , | racine , | juneau , | richland , buffalo , | kenosha , | rock , burnett , | | rusk , calumet , | kewaunee , | st. croix , chippewa , | la crosse , | clark , | lafayette , | sauk , | langlade , | sawyer , columbia , | lincoln , | shawano , crawford , | | sheboygan , dane , | manitowoc , | taylor , dodge , | marathon , | door , | marinette , | trempealeau , | marquette , | vernon , douglas , | milwaukee , | vilas , dunn , | | walworth , eau claire , | monroe , | washburn , florence , | oconto , | fond du lac , | oneida , | washington , | outagamie , | waukesha , forest , | ozaukee , | waupaca , grant , | | waushara , green , | pepin , | winnebago , green lake , | pierce , | | | wood , total , , wyoming.--area, , square miles. albany , | fremont , | sheridan , bighorn , | johnson , | sweetwater , carbon , | laramie , | uinta , converse , | natrona , | weston , crook , | park , | national park | | reservation total , population of cities of the united states _census of _ cities of over , population albany, n. y. , | minneapolis, minn. , atlanta, ga. , | nashville, tenn. , baltimore, md. , | newark, n. j. , birmingham, ala. , | new haven, conn. , boston, mass. , | new orleans, la. , | bridgeport, conn. , | new york, n. y. , , buffalo, n. y. , | oakland, cal. , cambridge, mass. , | omaha, neb. , chicago, ill. , , | paterson, n. j. , cincinnati, ohio , | philadelphia, pa. , , | cleveland, ohio , | pittsburgh, pa. , columbus, ohio , | portland, ore. , dayton, ohio , | providence, r. i. , denver, colo. , | richmond, va. , detroit, mich. , | rochester, n. y. , | fall river, mass. , | st. louis, mo. , grand rapids, mich. , | st. paul, minn. , indianapolis, ind. , | san francisco, cal. , jersey city, n. j. , | scranton, pa. , kansas city, mo. , | seattle, wash. , | los angeles, cal. , | spokane, wash. , louisville, ky. , | syracuse, n. y. , lowell, mass. , | toledo, ohio , memphis, tenn. , | washington, d. c. , milwaukee, wis. , | worcester, mass. , cities of from , to , population akron, ohio , | auburn, n. y. , allentown, pa. , | augusta, ga. , altoona, pa. , | aurora, ill. , amsterdam, n. y. , | austin, tex. , atlantic city, n. j. , | battle creek, mich. , bay city, mich. , | hoboken, n. j. , bayonne, n. j. , | holyoke, mass. , berkeley, cal. , | houston, tex. , binghamton, n. y. , | huntington, w. va. , bloomington, ill. , | jackson, mich. , | brockton, mass. , | jacksonville, fla. , brookline, mass. , | jamestown, n. y. , butte, mont. , | johnstown, pa. , camden, n. j. , | joliet, ill. , canton, ohio , | joplin, mo. , | cedar rapids, iowa , | kalamazoo, mich. , charleston, s. c. , | kansas city, kans. , charlotte, n. c. , | kingston, n. y. , chattanooga, tenn. , | knoxville, tenn. , chelsea, mass. , | la crosse, wis. , | chester, pa. , | lancaster, pa. , chicopee, mass. , | lansing, mich. , clinton, iowa , | lawrence, mass. , colorado springs, colo. , | lewiston, me. , columbia, s. c. , | lexington, ky. , | council bluffs, iowa , | lima, ohio , covington, ky. , | lincoln, nebr. , dallas, tex. , | little rock, ark. , danville, ill. , | lorain, ohio , davenport, iowa , | lynchburg, va. , | decatur, ill. , | lynn, mass. , des moines, iowa , | macon, ga. , dubuque, iowa , | mckeesport, pa. , duluth, minn. , | madison, wis. , easton, pa. , | malden, mass. , | east orange, n. j. , | manchester, n. h. , east st. louis, ill. , | meriden, conn. , el paso, tex. , | mobile, ala. , elgin, ill. , | montgomery, ala. , elizabeth, n. j. , | mount vernon, n. y. , | elmira, n. y. , | muskogee, okla. , erie, pa. , | nashua, n. h. , evansville, ind. , | newark, ohio , everett, mass. , | new bedford, mass. , fitchburg, mass. , | new britain, conn. , | flint, mich. , | newburgh, n. y. , fort wayne, ind. , | newcastle, pa. , fort worth, tex. , | newport, ky. , galveston, tex. , | newport, r. i. , green bay, wis. , | new rochelle, n. y. , | hamilton, ohio , | newton, mass. , harrisburg, pa. , | niagara falls, n. y. , hartford, conn. , | norfolk, va. , haverhill, mass. , | norristown, pa. , hazleton, pa. , | ogden, utah , oklahoma city, okla. , | south omaha, nebr. , orange, n. j. , | springfield, ill. , oshkosh, wis. , | springfield, mass. , pasadena, cal. , | springfield, mo. , passaic, n. j. , | springfield, ohio. , | pawtucket, r. i. , | stamford, conn. , peoria, ill. , | superior, wis. , perth amboy, n. j. , | tacoma, wash. , pittsfield, mass. , | tampa, fla. , portland, me. , | taunton, mass. , | portsmouth, va. , | terre haute, ind. , poughkeepsie, n. y. , | topeka, kans. , pueblo colo. , | trenton, n. j. , quincy, ill. , | troy, n. y. , quincy, mass. , | utica n. y. , | racine, wis. , | waco, tex. , heading, pa. , | waltham, mass. , roanoke, va. , | warwick, r. i. , rockford, ill. , | waterbury, conn. , sacramento, cal. , | waterloo, iowa , | saginaw, mich. , | watertown, n. y. , st. joseph, mo. , | west hoboken, n. j. , salem, mass. , | wheeling, w. va. , salt lake city, utah , | wichita, kans. , san antonio, tex. , | wilkes-barre, pa. , | san diego, cal. , | williamsport, pa. , san jose, cal. , | wilmington, del. , savannah, ga. , | wilmington, n. c. , schenectady, n. y. , | woonsocket, r. i. , sheboygan, wis. , | yonkers, n. y. , | shenandoah, pa. , | york, pa. , shreveport, la. , | youngstown, ohio , sioux city, iowa , | zanesville, ohio , somerville, mass. , | south bend, ind. , | number, acreage, and value of farms, by states: . -------+---------+-----------+---------------+--------------+-------------- | number | land | value of | value of | implements | of | in | farms. | farms. | and state.| farms. | farms. | (land.) | (buildings.) | machinery. | | (acres.) | | | -------+---------+-----------+---------------+--------------+-------------- the united | | | | states | , , | , , |$ , , , |$ , , , |$ , , , alabama , | , , | , , | , , | , , arizona , | , , | , , | , , | , , arkansas , | , , | , , | , , | , , california , | , , | , , , | , , | , , colorado , | , , | , , | , , | , , connecticut | | | | | , | , , | , , | , , | , , delaware , | , , | , , | , , | , , district of | | | | columbia | , | , , | , | , florida , | , , | , , | , , | , , georgia , | , , | , , | , , | , , idaho | , | , , | , , | , , | , , illinois , | , , | , , , | , , | , , indiana , | , , | , , , | , , | , , iowa | , | , , | , , , | , , | , , kansas | , | , , | , , , | , , | , , kentucky , | , , | , , | , , | , , louisiana , | , , | , , | , , | , , maine | , | , , | , , | , , | , , maryland , | , , | , , | , , | , , massachusetts | | | | | , | , , | , , | , , | , , michigan , | , , | , , | , , | , , minnesota , | , , | , , , | , , | , , mississippi | | | | | , | , , | , , | , , | , , missouri , | , , | , , , | , , | , , montana , | , , | , , | , , | , , nebraska , | , , | , , , | , , | , , nevada | , | , , | , , | , , | , , -------+---------+-----------+---------------+--------------+-------------- number, acreage, and value of farms, by states: .--continued -------------+--------+-----------+--------------+-------------+----------- | number | land | value of | value of | implements | of | in | farms. | farms. | and state. | farms. | farms. | (land.) |(buildings.) | machinery. | | (acres.) | | | -------------+--------+-----------+--------------+-------------+----------- new hampshire| , | , , | $ , , | $ , , | $ , , new jersey | , | , , | , , | , , | , , new mexico | , | , , | , , | , , | , , new york | , | , , | , , | , , | , , north | | | | | carolina | , | , , | , , | , , | , , north dakota | , | , , | , , | , , | , , ohio | , | , , | , , , | , , | , , oklahoma | , | , , | , , | , , | , , oregon | , | , , | , , | , , | , , pennsylvania | , | , , | , , | , , | , , porto rico | , | , , | , , | , , | , , rhode island | , | , | , , | , , | , , south | | | | | carolina | , | , , | , , | , , | , , south dakota | , | , , | , , | , , | , , tennessee | , | , , | , , | , , | , , texas | , | , , | , , , | , , | , , utah | , | , , | , , | , , | , , vermont | , | , , | , , | , , | , , virginia | , | , , | , , | , , | , , washington | , | , , | , , | , , | , , west virginia| , | , , | , , | , , | , , wisconsin | , | , , | , , | , , | , , wyoming | , | , , | , , | , , | , , -------------+--------+-----------+--------------+-------------+----------- table of occupations _census of _ all occupations (persons engaged in) , , agriculture, fisheries, and mining, total, , , agricultural labore , , apiarists , dairymen and dairywomen , farmers, planters, and overseers , , fishermen and oystermen , gardeners, florists, nurserymen, and vine growers , lumbermen and raftsmen , miners (coal) , miners (not otherwise specified) , quarrymen , stock raisers, herders, and drovers , wood choppers , other agricultural pursuits , professional service, , actors , architects , artists and teachers of art , authors and literary and scientific persons , chemists, assayers, and metallurgists , clergymen , dentists , designers, draughtsmen, and inventors , engineers (civil, mechanical, electrical, and mining and surveyors) , journalists , lawyers , musicians and teachers of music , officers of the united states army and navy , officials (government) , physicians and surgeons , professors in colleges and universities , teachers , theatrical managers, showmen, etc. , veterinary surgeons , other professional service , domestic and personal service, , , barbers and hairdressers , bartenders , boarding and lodging house keepers , engineers and firemen (not locomotive) , hotel keepers , housekeepers and stewards , hunters, trappers, guides, and scouts , janitors , laborers (not specified) , , launderers and laundresses , nurses and midwives , restaurant keepers , saloon keepers , servants , , sextons , soldiers, sailors, and marines (united states) , watchmen, policemen, and detectives , other domestic and personal service , trade and transportation, , , agents (claim, commission, real estate, insurance, etc.) and collectors , auctioneers , bankers and brokers (money and stocks) , boatmen and canalmen , bookkeepers and accountants , brokers (commercial) , clerks and copyists , commercial travellers , draymen, hackmen, teamsters, etc , foremen and overseers , hostlers , hucksters and pedlers , livery stable keepers , locomotive engineers and firemen , merchants and dealers in drugs and chemicals (retail) , merchants and dealers in drygoods (retail) , merchants and dealers in groceries (retail) , merchants and dealers in wines and liquors (retail) , merchants and dealers in wines and liquors (wholesale) , merchants and dealers not specified (retail) , merchants and dealers (wholesale), importers and shipping merchants , messengers, and errand and office boys , newspaper carriers and newsboys , officials of banks and insurance, trade, transportation, trust and other companies , packers and shippers , pilots , porters and helpers (in stores and warehouses) , sailors , salesmen and saleswomen , steam railroad employés (not otherwise specified) , stenographers and typewriters , trade and transportation.--_continued_. street railway employés , telephone and telegraph operators , telephone and telegraph linemen and electric light and power company employés , undertakers , weighers, gaugers, and measurers , other persons in trade and transportation , manufacturing and mechanical industries. , , agricultural implement makers (not otherwise classified) , apprentices (blacksmiths') , apprentices (boot and shoe makers') , apprentices (carpenters and joiners') , apprentices (carriage and wagon makers') apprentices (dressmakers') , apprentices (leather curriers', etc.) apprentices (machinists') , apprentices (masons') , apprentices (milliners') , apprentices (painters') , apprentices (plumbers') , apprentices (printers') , apprentices (tailors') , apprentices (tinsmiths') , apprentices (not otherwise specified ) , artificial flower makers , bakers , basket makers , blacksmiths , bleachers, dyers, and scourers , bone and ivory workers , bookbinders , boot and shoe makers and repairers , bottlers and mineral and soda-water makers , box makers (paper) , box makers (wood) , brass workers (not otherwise specified) , brewers and maltsters , brick and tile makers and terra cotta workers , britannia workers broom and brush makers , builders and contractors , butchers , butter and cheese makers , button makers , cabinetmakers , candle, soap, and tallow makers , carpenters and joiners , carpet makers , carriage and wagon makers (not otherwise classified) , charcoal, coke, and lime burners , chemical works employés , clock and watch makers and repairers , compositors , confectioners , manufacturing and mechanical industries.--_continued_. coopers , cooper workers , corset makers , cotton mill operatives , distillers and rectifiers , door, sash, and blind makers , dressmakers , electroplaters , electrotypers and stereotypers , engravers , fertilizer makers fish curers and packers , gas works employés , glass workers , glove makers , gold and silver workers , gunsmiths, locksmiths, and bell hangers , hair workers , harness and saddle makers and repairers , hat and cap makers , hosiery and knitting mill operatives , iron and steel workers , lace and embroidery makers , lead and zinc workers , leather curriers, dressers, finishers, and tanners , machinists , manufacturers and officials of manufacturing companies , marble and stone cutters , masons (brick and stone) , meat and fruit packers, canners, and preservers , mechanics (not otherwise specified) , metal workers (not otherwise specified) , mill and factory operatives (not specified) , millers (flour and grist) , milliners , model and pattern makers , moulders , musical instrument makers (not otherwise specified) nail and tack makers , oil well employés , oil works employés , painters, glaziers, and varnishers , paper hangers , paper mill operatives , photographers , piano and organ makers and tuners , plasterers , plumbers and gas and steam fitters , potters , powder and cartridge makers , printers, lithographers, and pressmen , print works operatives , publishers of books, maps, and newspapers , roofers and slaters , rope and cordage makers , rubber factory operatives , sail, awning, and tent makers , salt works employés , saw and planing mill employés , manufacturing and mechanical industries.--_continued_. seamstresses , sewing machine makers (not otherwise classified) sewing machine operators , ship and boat builders , shirt, collar, and cuff makers , silk mill operatives , starch makers steam boiler makers , stove, furnace, and grate makers , straw workers , sugar makers and refiners , tailors and tailoresses , tinners and tinware makers , tobacco and cigar operatives , tools and cutlery (not otherwise specified) , trunk, valise, leather case, and pocket-book 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science elementary practical and experimental physics by george m. hopkins revised and enlarged edition. two octavo volumes. , pages. illustrations. cloth bound, $ . . half morocco, $ . [illustration: books] the object of the work is to afford to the student, the artisan, the mechanic, and in fact all who are interested in science, whether young or advanced in years, a ready means of acquiring a general knowledge of physics by the experimental method. the leading principles of physics are illustrated by simple and inexpensive experiments and the endeavor has been made to make the explanations of both apparatus and experiment plain and easily understood. in the new edition, the scope of the work has been broadened and presents the more recent developments in modern science. an illustrated circular and complete table of contents sent free on application. * * * * * monoplanes and biplanes their design, construction and operation by grover cleveland loening, b.sc., a.m., c.e. mo, pages, illustrations. price, $ . postpaid [illustration: book] a new and authoritative work, covering the whole subject of the aeroplane, its design, and the theory on which its design is based, and containing a detailed description and discussion of thirty-eight of the more highly successful types. it is a thoroughly practical work, and invaluable to any one interested in aviation. the scientific exactness of the valuable data and references, as well as the high character of the innumerable illustrations and diagrams, renders this work, easily, the most useful, practical and complete that has as yet been contributed to the literature on aeroplanes. _an illustrated descriptive circular sent free on application._ mechanical movements, powers and devices by gardner d. hiscox, m. e. octavo, pages, , illustrations. price, $ . . this is a collection of , specially made illustrations of different mechanical movements, accompanied by appropriate descriptive text. it is practically a dictionary of mechanical movements, powers, devices and appliances and contains an illustrated description of the greatest variety of mechanical movements published in any language. this work covers nearly the whole range of the practical and inventive field, and is of much value to inventors, draughtsmen, mechanics, machinists, engineers and all others interested in any way in the devising and operation of mechanical work of any kind. * * * * * mechanical appliances, mechanical movements and novelties of construction by gardner d. hiscox, m. e. octavo, pages, illustrations. price, $ . . this book, while complete in itself, is in fact a supplement to the preceding volume. unlike the first volume, which is more elementary in character, this volume contains illustrations and descriptions of many combinations of motion and of mechanical devices and appliances found in different lines of machinery. each device is illustrated by a line drawing with a complete description, showing its working parts and the method of operation. the machines illustrated and described cover an immense field and have been carefully selected to supply the needs of those seeking either general or special information. special offer these two volumes sell for $ . each, but when both are ordered at one time, we send them prepaid to any address in the world on receipt of $ . . you save $ . by ordering the two volumes at one time. handy man's workshop and laboratory compiled and edited by a. russell bond mo, pages, illustrations. price, $ . [illustration: book] this is a compilation of hundreds of valuable suggestions and ingenious ideas for the mechanic and those mechanically inclined, and tells how all kinds of jobs can be done with home-made tools and appliances. the suggestions are practical, and the solutions to which they refer are of frequent occurrence. it may be regarded as the best collection of ideas of resourceful men published, and appeals to all those who find use for tools either in the home or workshop. the book is fully illustrated, in many cases with working drawings, which show clearly how the work is done. _send for a descriptive circular_ * * * * * home mechanics for amateurs by george m. hopkins mo, pages, illustrations. price, $ . [illustration: book] this is a thoroughly practical book by the most noted amateur experimenter in america. it deals with wood working, household ornaments, metal working, lathe work, metal spinning, silver working, making model engines, boilers, and water motors; making telescopes, microscopes and meteorological instruments, electrical chimes, cabinets, bells, night lights, dynamos and motors, electric light and electric furnace, and many other useful articles for the home and workshop. it appeals to the boy as well as the more mature amateur, and tells how to make things, the right way, at small expense. _a descriptive circular sent on application_ * * * * * to book buyers we have just issued a new revised edition of our general catalog, in which is listed some of the latest and best scientific and technical books published. a copy of this catalog will be sent free on application. munn & co., inc., publishers, broadway, new york +-----------------------------------------------------------------+ | transcriber's note. | | | | every effort has been made to replicate this text as faithfully | | as possible, including obsolete and variant spellings and other | | inconsistencies. | | | | minor punctuation and printing errors have been corrected. | | | | [*] madison (illinois), p. . the original has a footnote | | anchor, but no corresponding footnote appears in the text. | +-----------------------------------------------------------------+ [illustration] scientific american supplement no. new york, september , scientific american supplement. vol. xx., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents page i. chemistry and metallurgy.--the cowles electric smelting process. figures. on the electrical furnace and the reduction of the oxides of boron, silicon, aluminum, and other metals by carbon.--by eugene h. cowles, alfred h. cowles, and charles f. mabery. chemical action of light. eutexia.--cryohydrates.--eutectic salt alloys and metal alloys. chinoline. method of rapid estimation of urea. figure. assay of earthenware glaze. ii. engineering and mechanics.--deep shafts and deep mining. sinking of the quievrechain working shaft.--numerous figures. on the elementary principles of the gas engine.--an interesting paper read before the gas institute by mr. denny lane, of cork, and discussion following. m. meizel's reciprocating exhauster. automatic siphon for irrigation. figure. iii. electricity, telegraphy, etc.--optical telegraphy.-- cryptography.--preservation of telegrams.--the projector in optical telegraphy.--use of balloons. figures. a new style of submarine telegraph. figures. a new circuit cutter. figures. new micro telephonic apparatus. figures. messrs. kapp and crompton's measuring instruments. figures. iv. geology, etc.--permeability of sand rock.--by f.h. newell. the grotto of gargas, in the pyrenees.--paleontological remains found therein. engravings. remarkable wells and caverns in yucatan.--by alice d. le plongeon. v. natural history.--the cabbage butterfly and the peacock butterfly. vi. botany and horticulture.--the bhotan cypress (cupressus torulosa).--with engraving. the pitcher plant. what is a plant? camellias.--culture of the same. arisæma fimbriatum.--leaf, spathe, and floral details.--with engraving. vii. miscellaneous.--striking a light with bamboo. experiments in memory. * * * * * permeability of sand rock. by frederick h. newell, m.e. among oil producers, there has been much discussion as to whether the sand rock in which petroleum occurs is of necessity fissured or is still in its original unbroken condition. the earliest and most natural theory, which for years was indisputed, and is still given by some textbooks, was, that oil wells reached a cavity filled with petroleum. within the past few years, however, the opinion has been gaining ground that the oil is stored in the sandrock itself in the minute spaces between the small grains of sand, not entirely filled by cementing material, and that crevices holding and conducting oil are rare, all fissures as a rule being confined to the upper fresh-water bearing rocks of the well. mr. carll, in iii. pennsylvania second geological survey, has discussed this subject very fully, and has made estimates of the quantity of oil that the sand rock can hold and deliver into a well; also, t. sterry hunt, in his _chemical and geological essays_, has made deductions as to the petroleum contained in the niagara limestone that outcrops about chicago. while the experiments and conclusions of these geologists go to prove that these rocks are capable of holding the oil, there are on record no facts as to the phenomena of its flow, other than by capillarity, through the rock. to obtain some data of the flow of liquids under pressure through certain oil-bearing stones, series of tests on small pieces were made. these tests were carried on during this spring, and many results quite unlooked for were obtained. when crude oil, kerosene, or water (river or distilled) was forced through the specimens, the pressure being constant, the rate of flow was variable. at first, the amount flowing through was large, then fell off rapidly, and when the flow had diminished to about one-quarter of its original rate, the decrease was very slight, but still continued as long as measurements were made, in some cases for three weeks. when using crude oil, this result was not surprising, for, as the oil men say, crude oil "paraffines up" a rock, that is, clogs the minute pores by depositing solid paraffine (?); but this so-called paraffining took place, not only with crude oil, but with refined oil, and even with distilled water. the only explanation as yet is, that liquids flowing under pressure through rock on which they exert little or no dissolving effect, instead of washing out fine particles, tend to dislodge any minute grains of the stone that may not be firmly held by cement, and these block up extremely fine and crooked pores in which the fluid is passing. several tests indicated that this blocking up was largely near the surface into which the fluid was passing. when this surface was ground off, even / of an inch, the flow increased immediately nearly to the original rate. reversing the flow also had the effect of increasing the rate, even above that of any time previous. with the moderate pressures used--from " to " of mercury--the results show that the rate of flow, other things being equal, is directly proportional to the pressure. the porosity of rock is not always a criterion of its permeability; a very fine grained marble, containing about . per cent. cell space, transmitted water and oil more freely than a shale that would hold per cent. of its bulk of water. if the above conclusions hold on a large scale as on the small, they may aid in explaining the diminished flow of oil wells. not only will the flow lessen from reduced gas pressure, but the passages in the rock become less able to allow the oil to flow through. the increase in flow following the explosion of large shots in a sand rock may be due not only to fissuring of the rock, but to temporary reversal of the pressure, the force of the explosive tending to drive the oil back for an instant. the large shots now used (up to quarts, or say pounds of nitroglycerine) must exert some influence of this kind, especially when held down by ± feet of liquid tamping. in the course of these tests, it was noticed that fresh water has a more energetic disintegrating action on the shales and clay than on salt water. this may furnish a reason for the fact, noticed by the oil men, that fresh water has a much more injurious effect than salt in clogging a well. no oil-bearing sand rock is free from laminæ of shale, and when fresh water gets down into the sand, the water must, as the experiments show, rapidly break up the shale, setting free fine particles, which soon are driven along into the minute interstices of the sand rock, plastering it up and injuring the well.--_engineering and mining journal._ * * * * * the grotto of gargas. the grotto of gargas is located in mount tibiran about three hundred yards above the level of the valley, and about two miles southeast of the village of aventignan. access to it is easy, since a road made by mr. borderes in allows carriages to reach its entrance. this grotto is one of the most beautiful in the pyrenees, and presents to the visitor a succession of vast halls with roofs that are curved like a dome, or are in the form of an ogive, or are as flat as a ceiling. it is easy to explore these halls, for the floor is covered with a thick stalagmitic stratum, and is not irregular as in the majority of large caves. [illustration: fig. .--section of the grotto of gargas.] upon entering through the iron gate at the mouth of the grotto, one finds himself in bear hall, wherein a strange calcareous concretion offers the form of the carnivorous animal after which the room is named. this chamber is about feet in width by in length. we first descend a slope formed of earth and debris mostly derived from the outside. this slope, in which are cut several steps, rests upon a hard, compact, and crystalline stalagmitic floor. upon turning to the right, we come to the hall of columns, the most beautiful of all. here the floor bristles with stalagmites, which in several places are connected with the stalactites that depend from the ceiling. this room is about feet square. after this we reach the hall of crevices, feet square, and this leads to the great hall of gargas, which is about feet in length by , , and in width. in certain places enormous fissures in the vault rise to a great height. some of these, shaped like great inverted funnels, are more than yards in length. the grotto terminates in the creeping hall. as its name indicates, this part of the cave can only be traversed by lying flat upon the belly. it gives access to the upper grotto through a narrow and difficult passage that it would be possible to widen, and which would then allow visitors to make their exit by traversing the beautiful upper grotto, whose natural entrance is situated yards above the present one. this latter was blasted out about thirty years ago. upon following the direction of the great crevices, we reach a small chamber, wherein are found the oubliettes of gargas--a vertical well feet feet in depth. the aperture that gives access to this strange well (rendered important through the paleontological remains collected in it) is no more than two feet in diameter. such is the general configuration of the grotto. in dr. garrigou and mr. de chastaignier visited the grotto, and were the first to make excavations therein. these latter allowed these scientists to ascertain that the great chamber contained the remains of a quaternary fauna, and, near the declivity, a deposit of the reindeer age. as soon as it was possible to obtain a permit from the municipal council of aventignan to do so, i began the work of excavation, and the persistence with which i continued my explorations led me to discover one of the most important deposits that we possess in the chain of the pyrenees. my first excavations in bear hall were made in , and were particularly fruitful in an opening feet long by wide that terminates the hall, to the left. i have remarked that these sorts of retreats in grottoes are generally rich in bones. currents of water rushing through the entrance to the grotto carry along the bones--entire, broken, or gnawed--that lie upon the ground. these remains are transported to the depths of the cave, and are often stopped along the walls, and lie buried in the chambers in argillaceous mud. rounded flint stones are constantly associated with the bones, and the latter are always in great disorder. the species that i met with were as follows: the great cave bear, the little bear, the hyena, the great cat, the rhinoceros, the ox, the horse, and the stag. the stalagmitic floor is ½, , and ¼ inches thick. the bones were either scattered or accumulated at certain points. they were generally broken, and often worn and rounded. they appeared to have been rolled with violence by the waters. the clay that contained them was from to feet in thickness, and rested upon a stratum of water-worn pebbles whose dimensions varied from the size of the fist to a grain of sand. a thick layer of very hard, crystalline stalagmite covers the hall of columns, and it was very difficult to excavate without destroying this part of the grotto. i found that there anciently existed several apertures that are now sealed up, either by calcareous concretions or by earthy rubbish from the mountain. one of these was situated in the vicinity of the present mouth, and permitted of the access to bear hall of a host of carnivora that found therein a vast and convenient place of shelter. [illustration: fig. .--skeleton of the cave hyena.] these excavations revealed to me at this entrance, at the bottom of the declivity, a thick stratum of remains brought thither by primitive man. this deposit, which was formed of black earth mixed with charcoal and numerous remains of bones, calcined and broken longitudinally for the most part, contained rudely worked flint stones. i collected a few implements, one surface of which offered a clean fracture, while the other represented the cutting edge. according to mr. de mortillet, such instruments were not intended to have a handle. they were capable of serving as paring knives and saws, but they were especially designed for scraping bones and skins. the deposit was from to feet square and from inches to feet deep, and rested upon a bed of broken stones above the stalagmite. the animals found in it were the modern bear (rare), the aurochs, the ox, the horse, and the stag--the last four in abundance. at the extremity of the grotto there is a well with vertical sides which is no less than feet in depth. it is called the gargas oubilettes. its mouth is from to inches in diameter, and scarcely gives passage to a man (fig. ). mr. borderes, in the hope of discovering a new grotto, was the first to descend into this well, which he did by means of a rope ladder, and collected a few bones that were a revelation to me. despite the great difficulty and danger of excavating at this point, i proceeded, and found at the first blow of the pick that there was here a deposit of the highest importance, since all the bones that i met with were intact. the first thing collected was an entire skull of the great cave bear, with its maxillaries in place. from this moment i began a series of excavations that lasted two years. the descent is effected through a narrow vertical passage ½ feet in length. the cavity afterward imperceptibly widens, and, at a depth of yards, reaches ½ feet in diameter, and at yards feet. finally, in the widest part (at a depth of feet) it measures about feet (fig. ). a glance at the section of the well, which i have drawn as accurately as possible (not an easy thing to do when one is standing upon a rope ladder), will give an idea of the form of this strange pocket formed in the limestone of the mountain through the most complex dislocations and erosions. two lateral pockets attracted my attention because of the enormous quantity of clay and bones that obstructed them. the first, to the left, was about feet from the orifice. when we had entirely emptied it, we found that it communicated with the bottom of the well by a narrow passage. an entire skeleton of the great cave bear had stopped up this narrow passage, and of this, by the aid of a small ladder, we gathered the greater part of the skeleton, the state of preservation of which was remarkable. the second pocket, which was almost completely filled with clay, and situated a little lower than the other, likewise communicated with a third cavity that reached the bottom of the well. the clay of these different pockets contained so large a quantity of bones that we could hardly use our picks, and the excavation had to be performed with very short hooks, and often by hand. in this way i was enabled to remove the bones without accident. the lower pocket was dug out first, and with extreme care, the bones being hoisted out by means of a basket attached to a rope. three or four candles sufficed to give us light. the air was heavy and very warm, and, after staying in it for two hours, it was necessary to come to the surface to breathe. after extracting the bones from the lower pocket, and when no more clay remained, we successively dug out the upper ones and threw the earth to the bottom of the well. on the th of december, , my excavating was finished. to-day the oubliettes of gargas are obstructed with the clay that it was impossible to carry elsewhere. the animals that i thus collected in the well were the following: the great bear (in abundance), the little bear (a variety of the preceding), the hyena, and the wolf. the pockets contained nearly entire skeletons of these species. how had the animals been able to penetrate this well? it is difficult to admit that it was through the aperture that i have mentioned. i endeavored to ascertain whether there was not another communication with the gargas grotto, and had the satisfaction of finding a fissure that ended in the cave, and that probably was wider at the epoch at which the place served as a lair for the bear and hyena. very old individuals and other adults, and very young animals, were living in the grotto, and, being surprised, without power to save themselves, by a sudden inundation, reached the bottom of the well that we have described. the entire remains of these animals were carried along by the water and deposited in the pockets in the rock. once buried in the argillaceous mud, the bones no longer underwent the action of the running water, and their preservation was thence secured.--_f. regnault, in la nature._ * * * * * deep shafts and deep mining. a correspondent of the new york _sun_, writing from virginia city, nevada, describes the progress of the work there on the combination shaft of the comstock lode, the deepest vertical shaft in america, and the second deepest in the world. it is being sunk by the chollar potosi, hale & norcross, and savage mining companies; hence its name of the combination shaft. this shaft has now reached a perpendicular depth of a little over , feet. there is only one deeper vertical shaft in the world--the adalbent shaft of the silver-lead mines of przibram, bohemia, which at last accounts had reached a depth of , feet. the attainment of that depth was made the occasion of a festival, which continued three days, and was still further honored by the striking off of commemorative medals of the value of a florin each. there is no record of the beginning of work on this mine at przibram, although its written history goes back to . twenty years ago very few mining shafts in the world had reached a depth of , feet. the very deepest at that time was in a metalliferous mine in hanover, which had been carried down , feet; but this was probably not a single perpendicular shaft. two vertical shafts near gilly, in belgium, are sunk to the depth of , feet. at this point they are connected by a drift, from which an exploring shaft or winze is sunk to a further depth of feet, and from that again was put down a bore hole feet in depth, making the total depth reached , feet. as the bore hole did not reach the seam of coal sought for, they returned and resumed operations at the , level. in europe it is thought worthy of particular note that there are vertical shafts of the following depths: feet. eimkert's shaft of the luganer coal mining company, saxony , sampson shaft of the oberhartz silver mine, near st. andreasberg, hanover. , the hoisting shaft of the rosebridge colliery, near wigan, lancashire, england. , shaft of the coal mines of st. luke, near st. chaumont, france. , amelia shaft, shemnitz, hungary. , the no. camphausen shaft, near fishbach, in the department of the saarbruck collieries, prussia. , now, taking the mines of the comstock for a distance of over a mile--from the utah on the north to the alto on the south--there is hardly a mine that is not down over , feet, and most of the shafts are deeper than those mentioned above; while the union consolidated shaft has a vertical depth of , feet, and the yellow jacket a depth of , feet. in his closing argument before the congressional committee on mines and mining in , adolph sutro of the sutro tunnel said: "the deepest hole dug by man since the world has existed is only , feet deep, and it remains for the youngest nation on earth to contribute more to science and geology by giving opportunities of studying the formation of mineral veins at a greater depth than has ever been accomplished by any other nation in the world." mr. sutro was of the opinion that the completion of his tunnel would enable our leading mining companies to reach a vertical depth of , feet. this great depth has never yet been attained except in a bore hole or artesian well. the deepest points to which the crust of the earth has ever been penetrated have been by means of such borings in quest of salt, coal, or water. a bore hole for salt at probst jesar, near lubtheen, for the government of mecklenberg-schwerin, is down , feet, the size of which bore is twelve inches at the top and three inches at the bottom. a bore hole was put down for the prussian government to the depth of , feet. but in these bore holes the united states leads the world, as there is one near st. louis, mo., that is , feet in depth. here on the comstock, in the union consolidated mine, a depth of , feet has been attained, but not by means of a single vertical shaft. the vertical depth of the shaft is , feet; the remainder of the depth has been attained by means of winzes sunk from drifts. several long drifts were run at this great depth without difficulty as regards ventilation or heat. the combination shaft is situated much further east (in which direction the lode dips) than any other on the comstock. it is , feet east of the point where the great vein crops out on the side of mount davidson; , feet east of the old chollar-potosi shaft, , ft. east of the old hale & norcross (or fair) shaft, and , ft. east of the savage shaft. thus, it will be seen it is far out to the front in the country toward which the vein is going. the shaft is sunk in a very hard rock (andesite), every foot of which requires to be blasted. the opening is about thirty feet in length by ten feet in width. in timbering up this is divided into four different compartments, some for the hoisting and some for the pumping machinery, thus presenting the appearance at the top of four small shafts set in a row. over the shaft stand several large buildings, all filled with ponderous machinery. the sutro drain tunnel (nearly four miles in length) connects with the shaft at a depth of , ft., up to which point all the water encountered below is pumped. the shaft was sunk to the depth of , ft. before more water was encountered than could be hoisted out in the "skips" with the dirt. at the , level two cornish pumps, each with columns fifteen inches in diameter, were put in. at the , level the same pumps were used. on this level a drift was run that connected with the old hale & norcross and savage shafts, producing a good circulation of air both in the shaft and in the mines mentioned. at this point, on account of the inflow from the mines consequent upon connecting with them by means of the drift, they had more water than the cornish pumps could handle, and introduced the hydraulic pumps, which pumps are run by the pressure of water from the surface through a pipe running down from the top of the shaft, whereas the cornish pumps are run by huge steam engines. by means of the hydraulic pumps they were enabled to sink the shaft to the , level, and extended the cornish pumps to that point, where another set of hydraulic pumps was put in. they then sunk the shaft to the , level, when they ran another drift westward, and tapped the vein. the prospects at this depth in the hale & norcross and chollar mines were so encouraging that the management decided to sink the shaft to the depth of , ft. on reaching the , level, they ran a third drift through to the vein. the distance from the shaft to the east wall of the vein was found to be only ft. at the depth of , ft. they put in one of the pair of hydraulic pumps that is to be set up there. the second pump is now arriving from san francisco, and as soon as the several parts are on the ground, it will be at once put in place alongside its fellow on the , level. this additional pump will increase the capacity from , to , gallons in twenty-four hours, or about forty-five miners' inches. owing to the excellent showing of ore obtained on the , level by the hale & norcross company, and to the continuation of the ore below that level (as shown by a winze sunk in the vein), the management determined to sink the shaft to the vertical depth of , ft. it is now , ft. deep, and it is safe to say that it will reach the depth of , ft. early in september, when it will lack but eighty feet of being as deep as the shaft at przibram was at the time of the great festival. although the shaft is of great size--about thirty feet by ten feet before the timbers are put in--the workmen lower it at the rate of about three feet a day, in rock as hard as flint. the hydraulic pump now working at the , foot level of the shaft is the deepest in the world. in europe the deepest is in a mine in the hartz mountains, germany, which is working at the depth of , feet. it is, however, a small pump not half the size of the one in the combination shaft. although these pumps were first used in europe, those in operation here are far superior in size, and in every other respect, to those of the old world, several valuable improvements having been made in them by the machinists of the pacific coast. the capacity of the two cornish pumps, which lift the water from the , foot level to the sutro drain tunnel (at the , level), is about , , gallons in twenty-four hours, and the capacity of the present hydraulic pumps is , , gallons in the same time. they are now daily pumping, with both hydraulic and cornish pumps, about , , gallons, but could pump at least , gallons more in twenty-four hours than they are now doing. the daily capacity with the hydraulic pump now coming, and which will be set up as mate to that now in operation at the , foot level, will be , , gallons. the water which feeds the pressure pipe of the three sets of hydraulic pumps is brought from near lake tahoe, in the sierra nevada mountains. the distance is about thirty miles, and the greater part of the way the water flows through iron pipes, which at one point cross a depression , feet in depth. the pressure pipe takes this water from a tank situated on the eastern slope of mount davidson, , feet west of the shaft. at the tank this pipe is twelve inches in diameter, but is only eight inches where it enters the top of the shaft. the tank whence the water is taken is feet higher than the top of the shaft, therefore the vertical pressure upon the hydraulic pump at the , foot level is , feet. the pressure pipe is of ordinary galvanized iron where it receives the water at the tank, but gradually grows thicker and stronger, and at the , level it is constructed of cast iron, and is ½ inches in thickness. the pressure at this point is , pounds to the square inch. in the early days of hydraulic mining in california the miners thought that with a vertical pressure of feet they could almost tear the world to pieces, and not a man among them could have been made to believe that any pipe could be constructed that would withstand a vertical pressure of , feet; but we now see that a thickness of two and a half inches of cast iron will sustain a vertical pressure of over , feet. there is only one pressure pipe for all the hydraulic pumps. this extends from the tank on the side of the mountain to the , foot level. it is tapped at the points where are situated the several sets of hydraulic pumps. the water from the pressure pipe enters one part of the pump, where it moves a piston-back and forth, just as the piston of a steam engine is moved by steam. this water engine moves a pump which not only raises to the surface the water which has been used as driving power, but also a vast quantity of water from the shaft, all of which is forced up to the sutro drain tunnel through what is called a return pipe. each set of hydraulic pumps has its return pipe; therefore there are three return pipes--one from the , , one from the , , and another from the , level. some idea may be formed of the great size of these hydraulic engines when it is known that the stations excavated for them at the several levels where they are placed are feet long, feet wide, and feet high. all this space is so filled with machinery that only sufficient room is left to allow of the workmen moving about it. one of these stations would, on the surface, form a hall large enough for a ball room, and to those who are unacquainted with the skill of our miners it must seem wonderful that such great openings can be made and securely supported far down in the bowels of the earth; yet it is very effectually done. these great subterranean halls are supported by timbers × inches square set along the walls three feet apart, from center to center, and the caps or joists passing overhead are timbers of the same size. the timber used is mountain spruce. not one of these huge stations has thus far cost one dollar for repairs. the station at the , level has been in use five years, that at the , three years, and the one at the , level eight months. room for ventilation is left behind the timbers, and all are still sound. timbers of the same kind are used in the shaft, and all are sound. the shaft has cost nothing for repairs. being in hard andesite rock from top to bottom, the ground does not swell and crowd upon the timbers. if it shall be thought advisable to go to a greater depth than , feet, a station of large size will be made on the east side of the present shaft, and in this station will be sunk a shaft of smaller size. the reason why the work will be continued in this way is that in a single hoist of , feet the weight of a steel wire cable of that length is very great--so great that the loaded cage it brings up is a mere trifle in comparison. in this secondary shaft the hoisting apparatus and pumps will be run by means of compressed air. as it is very expensive to make compressed air by steam power, the pressure pipe will be tapped at the level of the sutro tunnel, and a stream of water taken out that will be used in running a turbine wheel of sufficient capacity to drive three air compressors. as there will be a vertical pressure upon the turbine at this depth of over , feet, a large stream of water will not be required. the water used in driving the wheel will flow out through the sutro tunnel, and give no trouble in the shaft. by means of this great shaft and its powerful hydraulic and cornish pumps the crust of the earth will probably yet be penetrated to far greater depth than in any other place in the world. it has been only a little over ten years since the work of sinking it was begun, whereas in the mines of the old world they have been delving since "time whereof the memory of man runneth not to the contrary." the work on the combination shaft has been by no means continuous. there have been long stoppages aside from those required at such times as they were engaged in running long drifts to the westward to tap the vein, and at times for many months, when the several companies interested in the shaft were engaged in prospecting the various levels it had opened up. * * * * * remarkable wells and caverns. yucatan is one of the most interesting states of mexico, owing to the splendid ancient palaces and temples of once grand cities, now hidden in the forests. that country also presents great attractions for geologists and botanists, as well as naturalists, who there find rare and beautiful birds, insects, and reptiles. there are no rivers on the surface of the land, but in many parts it is entirely undermined by extensive caverns, in which are basins of water fed by subterranean currents. the caverns are delightfully cool even at midday, and the fantastic forms of some of the stalactites and stalagmites are a never-ending source of interest. there are long winding passages and roomy chambers following one after another for great distances, with here and there some chink in the stony vault above, through which a sunbeam penetrates, enabling us to see to the right and left openings leading to untrodden places in the bowels of the earth. as few of these caves have been explored, the wildest accounts are given by the natives concerning the dark recesses where only wild beasts seek shelter. before venturing far in, it is advisable to secure one end of a ball of twine at the entrance, and keep the ball in hand; nor is it safe to go without lanterns or torches, lest we step into some yawning chasm or deep water. the leader of one party suddenly saw a very dark spot just before him; he jumped over, instead of stepping on it, and told the others to halt. examination proved the dark patch to be a pit that seemed bottomless. awe-inspiring as are the interiors of some of these caves, they are frequently most beautiful. the natural pillars are often grand in dimensions and sparkling with various hues, while stalactites and stalagmites sometimes resemble familiar objects with astonishing perfection. it is, however, not advisable to place implicit confidence in accounts of the natives, for the reality, no matter how beautiful, can hardly be equal to what the vivid imagination of the indian has pictured. anything bearing the least resemblance to a woman is called "a most beautiful virgin mary." fantastic flutings become "an organ," and a level rock "an altar." only once we were not disappointed, when, having been told to look for a pulpit, we found one that appeared as if man must have fashioned it, supported on a slender pyramidal base, the upper part very symmetrical, and ornamented with a perfect imitation of bunches of grapes and other fruit. as i have already said, in these caves are sheets of water, some very large, others only a few feet in circumference, fed by subterranean currents. when the water is clear and sweet, it is peopled by a kind of bagre, a blind fish called by the natives _tzau_, also a species of _silurus_. but there are likewise medicinal and thermal waters, by bathing in which many people claim to have been cured of most painful and obstinate diseases. strange stories are told of some of these waters. of one it is said that those who approach it without holding their breath fall dead. people who live near the place swear it is so, and say the water appears to boil on such occasions. from the thermal waters, in some cases feet below the soil, and without means of access except by buckets let down through an opening in the rock, warm vapors issue at early morn, but when the sun is high the water is cool and pleasant to drink. the name _senote_ is given to all these deposits of water, also to some immense natural circular wells from to feet in diameter. the walls are more or less perpendicular, generally covered with tropical vegetation. the current in some is swift, but no inlets or outlets are visible. the water is deliciously pure and sweet, much better than that of wells opened by man in the same country. these enormous deposits generally have a rugged path, sometimes very steep, leading to the water's edge, but daring natives throw themselves from the brink, afterward ascending by stout roots that hang like ropes down the walls, the trees above sucking through these roots the life-sustaining fluid more than a hundred feet below. in the west part of yucatan is a village called _bolonchen_ (nine wells), because in the public square there are nine circular openings cut through a stratum of rock. they are mouths of one immense cistern, if natural or made by hand the natives do not know, but in times of drought it is empty, which shows that it is not supplied by any subterranean spring. then the people depend entirely on water found in a cave a mile and a half from the village; it is perhaps the most remarkable cavern in the whole country. the entrance is magnificently wild and picturesque. it is necessary to carry torches, for the way is dark and dangerous. after advancing sixty or seventy feet we descend a strong but rough ladder twenty feet long, placed against a very precipitous rock. not the faintest glimmer of daylight reaches that spot; but after a while we stand on the brink of a perpendicular precipice, the bottom of which is strongly illuminated through a hole in the surface rock more than feet above. standing on the verge of this awful pit in the dim light, the rocks and crags seem to take on most weird shapes. we go down into the great hole by a ladder eighty feet high and twelve wide, and, reaching the bottom, are as yet but at the mouth of the cave, which, by the bye, is called _xtacunbi xunan_ (the hidden lady), because, say the indians, a lady was stolen from her mother and hidden there by her lover. now, to our right, we find a narrow passage, and soon another ladder; the darkness is intense and the descent continuous, though irregular, like a series of hills and dales, ladders being placed against the steepest places. after an exhausting journey we reach a vast chamber, from which crooked passages lead in various directions to wells, seven in all, each named according to the peculiar kind of water. one, always warm, is called _chocohá_ (hot water); another, _o[c]ihá_* (milky water), and _akabhá_ (dark water). about paces away from the chamber, passing through a very narrow, close passage, there is a basin of red water that ebbs and flows like the sea, receding with the south wind, increasing with the northwest. *transcriber's note: [c] denotes upside-down 'c' in original. to reach the most distant well, we go down yet one more ladder, the seventh. on one side of it there is a perpendicular wall, on the other a yawning gulf, so when one of the steps, merely round sticks tied with withes, gave way beneath our feet, we tightly grasped the stick above. having reached the bottom of the ladder, we crawl on our hands and feet through a broken, winding passage about feet long, then see before us a basin of crystalline water, and how thirsty we are! this basin is , feet from the mouth of the cave, and about feet below the earth's surface. several hundred people during five months in every year depend entirely on that source for all the water they use. with their frail pitchers and flaring torches they wend their way, gasping for breath, through the intricate passages, and reaching the water, are so profusely perspiring that they must wait before quenching their thirst. the way back is even harder, and they are tired and loaded; yet these people are such lovers of cleanliness that on their arrival at their poor huts, before tasting food, they will use some of the water that has cost them so much, to bathe their smoke-begrimed skin. as several women once fainted in the cave, men generally fetch the water now. yucatan is, and has been for ages past, quite free from earthquakes, while all surrounding countries are from time to time convulsed. this immunity may be due to the vast caverns and numerous great wells existing throughout the land. pliny the elder was of opinion that if numerous deep wells were made in the earth to serve as outlets for the gases that disturb its upper strata, the strength of the earthquakes would be diminished, and if we may judge by yucatan, pliny was right in his conjectures. after him, other scientists who have carefully studied the subject have expressed the same opinion with regard to the efficacy of large wells. alice d. le plongeon. brooklyn, july , . * * * * * cholera failed to strike a single one of the , women employed in the national tobacco factory at valencia, spain, though the disease raged violently in that city, and the _medical world_ recalls that tobacco workers were also noticed to enjoy exemption from attack during an epidemic at amsterdam. * * * * * the cabbage butterfly. a patch of eggs and the minute caterpillars or larvæ nearly emerged from them are seen on the leaf. these tiny eggs are at first quite white or pale yellow, and form an object for the microscope of remarkable beauty, which is worthy of the examination of all who take an interest in the garden and its insect life. an egg magnified is drawn at the bottom left-hand corner of the woodcut. when the eggs are near the hatching point they darken in color, and a magnifying glass reveals through the delicate transparent shell a sight which fills the observer with amazement; the embryo caterpillar is seen in gradual course of formation, and if patience and warmth have permitted it, the observer will witness slight movements within the life-case, and presently the shell will break and a black head with moving jaws will be thrust out; the little caterpillar unfolds and slowly crawls away from the egg-shell, and inserts its jaws into the green leaf. it is curious to witness how judiciously the little creatures avoid crowding together, but strike out in different directions, and thus they make sure of a plentiful supply of food, and distribute the effects of their depredations. these caterpillars eat continually, and hence rapidly increase in size, until they present the appearance shown in our drawing at the bottom of the illustration, which is a full grown caterpillar. [illustration: the cabbage and peacock butterflies.] it will be observed that this insect is composed of thirteen segments from head to tail, which is a distinctive characteristic of all insects both in the larval and perfect states; but in the case of this and most other caterpillars these segments are sharply defined and readily recognized. it will also be noticed that the three segments or "joints" nearest the head bear a pair of legs each; these are the real feet, or claspers, as they are sometimes termed, which develop into the feet of the future butterfly. there are four pairs of false feet or suckers, which adhere to the ground by suction, and which disappear in the butterfly. on the last or tail end is a fifth pair of suckers also, which can attach themselves to a surface with considerable force, as any one can attest who has noticed the wrigglings of one of these caterpillars when feeling for new feeding ground. the caterpillar now ceases to eat, and quietly betakes itself to a secluded corner, where in peace it spins a web around its body, and wrapt therein remains quiescent, awaiting its change into the butterfly. although so dormant outwardly, activity reigns inside; processes are going on within that chrysalis-case which are the amazement and the puzzle of all naturalists. in course of time the worm is changed into the beautiful winged butterfly, which breaks its case and emerges soft and wet; but it quickly dries and spreads its wings to commence its life in the air and sunshine. the chrysalis is represented in the figure on the left. the butterfly, it will be recognized, is one of the common insects so familiar to all, with strongly veined white wings, bearing three black spots, two on the upper and one on the lower wing, and dark coloring on the corner of the upper wings. the antennæ, as with all butterflies, are clubbed at the extremity--unlike moths', which are tapering--and the large black staring eyes are the optical apparatus, containing, we are told, thousands of lenses, each a perfect, simple eye. the wings derive their chief coloring from the covering of scales, which lie on like slates on a roof, and are attached in a similar manner. a small portion of the wing magnified is represented at the bottom right hand corner, and detached scales more highly magnified next to it, exhibiting somewhat the form of battledoors. the peacock butterfly. another well known insect is illustrated in the figure in the upper portion--the peacock butterfly (vanessa io). the curious spiked and spotted caterpillar feeds upon the common nettle. this beautiful butterfly--common in most districts--is brilliantly colored and figured on the upper side of the wings, but only of a mottled brown on the under surface, somewhat resembling a dried and brown leaf, so that it is no easy matter to detect the conspicuous, brightly-decked insect when it alights from flight upon foliage, and brings its wings together over its back after the manner of butterflies. at the left-hand corner is seen the head of the insect, magnified, showing the long spiral tongue. this is a curious structure, and one that will repay the trouble of microscopic examination. in the figure the profile is seen, the large compound eye at the side and the long curved tongue, so elephantine-looking in form, though of minute size, is seen unrolled as it is when about to be inserted into flowers to pump up the honey-juice. this little piece of insect apparatus is a mass of muscles and sensitive nerves comprising a machine of greater complexity and of no less precision in its action than the modern printing machine. when not in use, the tongue rolls into a spiral and disappears under the head. a butterfly's tongue may readily be unrolled by carefully inserting a pin within the first spiral and gently drawing it out.--_the gardeners' chronicle._ * * * * * the bhotan cypress. (cupressus torulosa.) this cypress, apart from its elegant growth, is interesting as being the only species of cupressus indigenous to india. it is a native of the himalayas in the bhotan district, and it also occurs on the borders of chinese tartary. it forms, therefore, a connecting link, as it were, between the true cypresses of the extreme east and those that are natives of europe. it is singular to note that this genus of conifers extends throughout the entire breadth of the northern hemisphere, cupressus funebris representing the extreme east in china, and c. macrocarpa the extreme west on the californian seacoast. the northerly and southerly limits, it is interesting to mark, are, on the contrary, singularly restricted, the most southerly being found in mexico; the most northerly (c. nutkaensis) in nootka sound, and the subject of these remarks (c. torulosa) in bhotan. the whole of the regions intervening between these extreme lateral points have their cypresses. the european species are c. lusitanica (the cedar of goa), which inhabits spain and portugal; c. sempervirens (the roman cypress), which is centered chiefly in the southeasterly parts of europe, extending into asia minor. farther eastward c. torulosa is met with, and the chain is extended eastward by c. funebris, also known as c. pendula. the headquarters of the cypresses are undoubtedly in the extreme west, for here may be found some four or five distinct species, including the well-known c. lawsoniana, probably the most popular of all coniferæ in gardens, c. goveniana, c. macnabiana, c. macrocarpa, and c. nutkaensis (spelt c. nutkanus by the californian botanists). the eastern representative of the cypresses in the united states of north america is c. thyoides, popularly known as the white cedar. in mexico three or four species occur, so that the genus in round numbers only contains about a dozen species. the californian botanist mr. sereno watson takes away lawson's cypress from cupressus and puts it in the genus chamæcyparis, the chief points of distinction being the flattened two-ranked branchlets and the small globose cones maturing the first year. [illustration: cones of cupressus torulosa (natural size).] all the cypresses are undoubtedly valuable from a garden point of view, but the various species vary in degree as regards their utility as ornamental subjects. i should rank them in the following order in point of merit: c. lawsoniana, c. nutkaensis, c. macrocarpa, c. sempervirens, c. thyoides, c. macnabiana, and c. goveniana; then would follow c. torulosa, c. funebris, c. knightiana, and other mexican species. these are placed last, not because they are less elegant than the others, but on account of their tenderness, all being liable to succumb to our damp and cold winters. the species which concerns us at present, c. torulosa, is an old introduction, seeds of it having been sent to this country by wallich so long back as , and previous to this date it was found by royle on the himalayas, growing at elevations of some , feet above sea level. coming from such a height, one would suppose it to be hardier than it really is, but its tenderness may probably be accounted for by the wood not getting thoroughly ripened during our summers. it is a very handsome tree, said to reach from feet to feet in height in its native habitat. it has a perfectly straight stem; the growth is pyramidal or rather conical, and the old wood is of a warm purplish-brown. the foliage is a glaucous gray-green, and the branches have a twisted and tufted appearance. there are several varieties of it which are, or have been, in cultivation. of these one of the best is corneyana, which gordon ranked as a distinct species. it was supposed to be chinese, and was introduced to cultivation by messrs. knight & perry, the predecessors of messrs. veitch at the chelsea nurseries. it differs from c. torulosa proper, its habit being of low stature, and has slender pendulous branches; hence, it has been known in gardens by the names of c. gracilis, c. cernua, and c. pendula. other varieties of c. torulosa are those named in gardens and nurseries--viridis, a kind devoid of the glaucous foliage of the original; majestica, a robust variety; and nana, a very dwarf and compact-growing sort. there is also a so-called variegated form, but it is not worthy of mention. the synonyms of c. torulosa itself are c. cashmeriana, c. nepalensis, and c. pendula. having regard to the tenderness of this bhotan cypress, it should only be planted in the warmest localities, and in dry sheltered positions; upland districts, too, provided they are sheltered, are undoubtedly suitable for it, inasmuch as growth is retarded in spring, and, therefore, the young shoots escape injury from late spring frosts.--_w.g., in the garden._ * * * * * the pitcher plant. the variety of the pitcher plant (_sarracenia variolaris_) found in north america is carnivorous, being a feeder on various animal substances. mrs. mary treat, an american naturalist, made, a few years ago, several experiments upon the plants of this species to be found in florida; and to the labors of this lady the writer has been indebted, in some measure, in the preparation of this paper. the _sarracenia_ derives its name of "pitcher plant" from the fact of its possessing the following curious characteristics: the median nerve is prolonged beyond the leaves in the manner of a tendril, and terminates in a species of cup or urn. this cup is ordinarily three or four inches in depth, and one to one and a half inches in width. the orifice of the cup is covered with a lid, which opens and shuts at certain periods. at sunrise the cup is found filled with sweet, limpid water, at which time the lid is down. in the course of the day the lid opens, when nearly half the water is evaporated; but during the night this loss is made up, and the next morning the cup is again quite full, and the lid is shut. about the middle of march the plants put forth their leaves, which are from six to twelve inches long, hollow, and shaped something like a trumpet, while the aperture of the apex is formed almost precisely in the same manner as those of the plants previously described. a broad wing extends along one side of the leaf, from the base to the opening at the top; this wing is bound or edged with a purple cord, which extends likewise around the cup. this cord secretes a sweet fluid, and not only flying insects, but those also that crawl upon the ground, are attracted by it to the plants. ants, especially, are very fond of this fluid, so that a line of aphides, extending from the base to the summit of a leaf, may frequently be observed slowly advancing toward the orifice of the cup, down which they disappear, never to return. flying insects of every kind are equally drawn to the plant; and directly they taste the fluid, they act very curiously. after feeding upon the secretions for two or three minutes they become quite stupid, unsteady on their feet, and while trying to pass their legs over their wings to clear them, they fall down. it is of no use to liberate any of the smaller insects; every fly, removed from the leaf upon which it had been feeding, returned immediately it was at liberty to do so, and walked down the fatal cup as though drawn to it by a species of irresistible fascination. it is not alone that flies and other small insects are overpowered by the fluid which exudes from the cord in question. even large insects succumb to it, although of course not so quickly. mrs. treat says: "a large cockroach was feeding on the secretion of a fresh leaf, which had caught but little or no prey. after feeding a short time the insect went down the tube so tight that i could not dislodge it, even when turning the leaf upside down and knocking it quite hard. it was late in the evening when i observed it enter; the next morning i cut the tube open; the cockroach was still alive, but it was covered with a secretion produced from the inner surface of the tube, and its legs fell off as i extricated it. from all appearance the terrible _sarracenia_ was eating its victim alive. and yet, perhaps, i should not say 'terrible,' for the plant seems to supply its victims with a lethe-like draught before devouring them." if only a few insects alight upon a leaf, no unpleasant smell is perceptible during or after the process of digestion; but if a large number of them be caught, which is commonly the case, a most offensive odor emanates from the cup, although the putrid matter does not appear to injure in any manner the inner surface of the tube, food, even in this condition, being readily absorbed, and going to nourish the plant. in fact, it would seem that the _sarracenia_, like some animals, can feed upon carrion and thrive upon it. in instances in which experiments have been made with fresh, raw beef or mutton, the meat has been covered in a few hours with the secretions of the leaves, and the blood extracted from it. there is, however, one difference between the digesting powers of the leaves when exercised upon insects or upon meat. even if the bodies of insects have become putrid, the plant, as has already been stated, has no difficulty in assimilating them; but as regards meat, it is only when it is perfectly sweet that the secretions of the leaves will act upon it. the pitcher plant undoubtedly derives its principal nourishment from the insects it eats. it, too--unlike most other carnivorous plants, which, when the quantity of food with which they have to deal is in excess of their powers of digestion, succumb to the effort and die--appears to find it easy to devour any number of insects, small or large, the operation being with it simply a question of time. flies, beetles, or even cockroaches, at the expiration of three or four days at most, disappear, nothing being left of them save their wings and other hard, parts of their bodies. the _sarracenia_ is, indeed, not only the most voracious of all known species of carnivorous plants, but the least fastidious as to the nature of the food upon which it feeds.--_w.c.m., nature._ * * * * * what is a plant? mr. worsley-benison has been discussing this question in a very interesting way, and he says in conclusion that "_physiologically_ the most distinctive feature of plant-life is the power to manufacture protein from less complex bodies; that of animal-life, the absence of such power." he finds that in form, in the presence of starch, of chlorophyl, in power of locomotion, in the presence of circulatory organs, of the body called nitrogen, in the functions of respiration and sensation, there are no diagnostic characters. he finds, however, "fairly constant and well-marked distinctions" in the presence of a cellulose coat in the plant-cell, in digestion followed by absorption, and in the power to manufacture protein. the _morphological_ feature of plants is this cellulose coat; of animals, its absence; the _physiological_ peculiarity of plants, this _manufacturing power_; of animals, the want of it. but after all the discussion he says: "to the question, _is this an animal or a plant?_ we must often reply, _we do not know_."--_the microscope._ * * * * * camellias. next to the rose, no flower* is more beautiful or more useful than the camellia. it may readily be so managed that its natural season of blooming shall be from october to march, thus coming in at a time when roses can hardly be had without forcing. in every quality, with the single exception of scent, the camellia may be pronounced the equal of the rose. it can be used in all combinations or for all purposes for which roses can be employed. in form and color it is probably more perfect, and fully as brilliant. it is equally or more durable, either on the plant or as a cut flower. it is a little dearer to buy, and perhaps slightly more difficult to cultivate; but like most plants the camellia has crucial periods in its life, when it needs special treatment. that given, it may be grown with the utmost ease; that withheld, its culture becomes precarious, or a failure. the camellia is so hardy that it will live in the open air in many parts of great britain, and herein lies a danger to many cultivators. because it is quite or almost hardy, they keep it almost cool. this is all very well if the cool treatment be not carried to extremes, and persisted in all the year round. camellias in a dormant state will live and thrive in any temperature above the freezing point, and will take little or no hurt if subjected to from °- ° below it, or a temperature of ° fahr. * transcriber's note: original "flour". they will also bloom freely in a temperature of °, though ° suits them better. hence, during the late summer and early autumn it is hardly possible to keep camellias too cool either out of doors or in. they are also particularly sensitive to heat just before the flower-buds begin to swell in late autumn or winter; a sudden or sensible rise of temperature at that stage sends the flower-buds off in showers. this is what too often happens, in fact, to the camellias of amateurs. no sooner do the buds begin to show then a natural impatience seizes the possessor's of well-budded camellias to have the flowers opened. more warmth, a closer atmosphere, is brought to bear upon them, and down fall the buds in showers on stage or floor--the chief cause of this slip between the buds and the open flowers being a rise of temperature. a close or arid atmosphere often leads to the same results. camellias can hardly have too free a circulation of air or too low a temperature. another frequent cause of buds dropping arises from either too little or too much water at the roots. either a paucity or excess of water at the roots should lead to identical results. most amateurs overwater their camellias during their flowering stages. seeing so many buds expanding, they naturally rush to the conclusion that a good deal of water must be used to fill them to bursting point. but the opening of camellia buds is less a manufacture than a mere development, and the strain on the plant and drain on the roots is far less during this stage than many suppose. of course the opposite extreme of over-dry roots must be provided against, else this would also cause the plants to cast off their buds. but our object now is less to point out how buds are to be developed into fully expanded flowers than to show how they were to be formed in plenty, and the plants preserved in robust health year after year. one of the simplest and surest modes of reaching this desirable end is to adopt a system of semi-tropical treatment for two months or so after flowering. the moment or even before the late blooms fade, the plants should be pruned if necessary. few plants bear the knife better than camellias, though it is folly to cut them unless they are too tall or too large for their quarters or have grown out of form. as a rule healthy camellias produce sufficient or even a redundancy of shoots without cutting back; but should they need pruning, after flowering is the best time to perform the operation. during the breaking of the tender leaves and the growth of the young shoots in their first stages, the plant should be shaded from direct sunshine, unless, indeed, they are a long way from the glass, when the diffusion and dispersion of the rays of light tone down or break their scorching force; few young leaves and shoots are more tender and easily burned than camellia, and scorching not only disfigures the plants, but also hinders the formation of fine growths and the development of flower-buds. the atmosphere during the early season of growth may almost touch saturation. it must not fail to be genial, and this geniality of the air must be kept up by the surface-sprinkling of paths, floors, stages, walls, and the plants themselves at least twice a day. with the pots or border well drained it is hardly possible to overwater the roots of camellias during their period of wood-making. the temperature may range from ° to ° during most of the period. as the flower-buds form, and become more conspicuous, the tropical treatment may become less and less tropical, until the camellias are subjected to the common treatment of greenhouse or conservatory plants in summer. even at this early stage it is wise to attend to the thinning of the buds. many varieties of camellias--notably that most useful of all varieties, the double white--will often set and swell five or ten times more buds than it ought to be allowed to carry. nothing is gained, but a good deal is lost, by allowing so many embryo flower-buds to be formed or partially developed. it is in fact far wiser to take off the majority of the excess at the earliest possible point, so as to concentrate the strength of the plant into those that remain. as it is, however, often a point of great moment to have a succession of camellia flowers for as long a period as possible on the same plants, buds of all sizes should be selected to remain. fortunately, it is found in practice that the plants, unless overweighted with blooms, do not cast off the smaller or later buds in their efforts to open their earlier and larger ones. with the setting, thinning, and partial swelling of the flower-buds the semi-tropical treatment of camellias must close; continued longer, the result would be their blooming out of season, or more probably their not blooming at all. the best place for camellias from the time of setting their flower-buds to their blooming season is a vexed question, which can hardly be said to have been settled as yet. they may either be left in a cool greenhouse, or placed in a shaded, sheltered position in the open air. some of the finest camellias ever seen have been placed in the open air from june to october. these in some cases have been stood behind south, and in others behind west walls. those facing the east in their summer quarters were, on the whole, the finest, many of them being truly magnificent plants, not a few of them having been imported direct from florence at a time when camellias were far less grown in england than now. in all cases where camellias are placed in the open air in summer, care will be taken to place the pots on worm proof bases, and to shield the tops from direct sunshine from to o'clock. if these two points are attended to, and also shelter from high winds, it matters little where they stand. in all cases it is well to place camellias under glass shelter early in october, less for fear of cold than of saturating rains causing a sodden state of the soil in the pots. while adverting, however, to the safety and usefulness of placing camellias in the open air in summer, it must not be inferred that this is essential to the successful culture; it is, in fact, far otherwise, as the majority of the finest camellias in the country are planted out in conservatories with immovable roofs. many such houses are, however, treated to special semi-tropical treatment as has been described, and are kept as cool and open as possible after the flower-buds are fairly set, so that the cultural and climatic conditions approximate as closely as possible to those here indicated. soil and seasons of potting may be described as vexed questions in camellia culture. as to the first, some affect pure loam, others peat only, yet more a half and half of both, with a liberal proportion of gritty sand, or a little smashed charcoal or bruised bones as porous or feeding agents, or both. most growers prefer the mixture, and as good camellias are grown in each of its constituents, it follows without saying that they may also be well grown in various proportions of both. under rather than over potting suits the plants best, and the best time is doubtless just before they are about to start into fresh growth, though many good cultivators elect to shift their plants in the late summer or autumn, that is, soon after the growth is finishing, and the flower-buds fairly and fully set for the next season. from all which it is obvious that the camellia is not only among the most useful and showy, but likewise among the most accommodating of plants. under good cultivation it is also one of the cleanest, though when scab gets on it, it is difficult to get rid of it. mealy-bugs also occasionally make a hurried visit to camellias when making their growth, as well as aphides. but the leaves once formed and advanced to semi-maturity are too hard and leathery for such insects, while they will bear scale being rubbed off them with impunity. but really well-grown camellias, as a rule, are wholly free from insect pests, and their clean, dark, glossy leaves are only of secondary beauty to their brilliant, exquisitely formed, and many sized flowers.--_d.t., the gardeners' chronicle._ * * * * * arisÆma fimbriatum. _mast.; sp. nov._ [illustration: arisÆma fimbriatum: leaf, spathe, and floral details.] some few years since we had occasion to figure some very remarkable himalayan species of this genus, in which the end of the spadix was prolonged into a very long, thread-like appendage thrown over the leaves of the plant or of its neighbors, and ultimately reaching the ground, and thus, it is presumed, affording ants and other insects means of access to the flowers, and consequent fertilization. these species were grown by mr. elwes, and exhibited by him before the scientific committee. the present species is of somewhat similar character, but is, we believe, new alike to gardens and to science. we met with it in the course of the autumn in the nursery of messrs. sander, at st. alban's; but learn that it has since passed into the hands of mr. w. bull, of chelsea. it was imported accidentally with orchids, probably from the philippine islands. it belongs to engler's section, trisecta, having two stalked leaves, each deeply divided into three ovate acute glabrous segments. the petioles are long, pale purplish, rose-colored, sprinkled with small purplish spots. the spathes are oblong acute or acuminate, convolute at the base, brownish-purple, striped longitudinally with narrow whitish bands. the spadix is cylindrical, slender, terminating in along, whip-like extremity, much longer than the spathe. the flowers have the arrangement and structure common to the genus, the females being crowded at the base of the spadix, the males immediately above them, and these passing gradually into fleshy incurved processes, which in their turn pass gradually into long, slender, purplish threads, covering the whole of the free end of the spadix.--_m.t.m., in the gardeness' chronicle._ * * * * * striking a light. in the new edition of mason's "burma" we read that among other uses to which the bamboo is applied, not the least useful is that of producing fire by friction. for this purpose a joint of thoroughly dry bamboo is selected, about ½ inches in diameter, and this joint is then split in halves. a ball is now prepared by scraping off shavings from a perfectly dry bamboo, and this ball being placed on some firm support, as a fallen log or piece of rock, one of the above halves is held by its ends firmly down on it, so that the ball of soft fiber is pressed with some force against its inner or concave surface. another man now takes a piece of bamboo a foot long or less, and shaped with a blunt edge, something like a paper knife, and commences a sawing motion backward and forward across the horizontal piece of bamboo, and just over the spot where the ball of soft fiber is held. the motion is slow at first, and by degrees a groove is formed, which soon deepens as the motion increases in quickness. soon smoke arises, and the motion is now made as rapid as possible, and by the time the bamboo is cut through not only smoke but sparks are seen, which soon ignite the materials of which the ball beneath is composed. the first tender spark is now carefully blown, and when well alight the ball is withdrawn, and leaves and other inflammable materials heaped over it, and a fire secured. this is the only method that i am aware of for procuring fire by friction in burma, but on the hills and out of the way parts, that philosophical toy, the "pyrophorus," is still in use. this consists[ ] of a short joint of a thick woody bamboo, neatly cut, which forms a cylinder. at the bottom of this a bit of tinder is placed, and a tightly-fitting piston inserted composed of some hard wood. the tube being now held in one hand, or firmly supported, the piston is driven violently down on the tinder by a smart blow from the hand, with the result of igniting the tinder beneath. [footnote : it is also made of a solid cylinder of buffalo's horn, with a central hollow of three-sixteenths of an inch in diameter and three inches deep burnt into it. the piston, which fits very tightly in it, is made of iron-wood or some wood equally hard.] another method of obtaining fire by friction from bamboos is thus described by captain t.h. lewin ("hill tracts of chittagong, and the dwellers therein", calcutta, , p. ), as practiced in the chittagong hills. the tipporahs make use of an ingenious device to obtain fire; they take a piece of dry bamboo, about a foot long, split it in half, and on its outer round surface cut a nick, or notch, about an eighth of an inch broad, circling round the semi-circumference of the bamboo, shallow toward the edges, but deepening in the center until a minute slit of about a line in breadth pierces the inner surface of the bamboo fire-stick. then a flexible strip of bamboo is taken, about ½ feet long and an eighth of an inch in breadth, to fit the circling notch, or groove, in the fire-stick. this slip or band is rubbed with fine dry sand, and then passed round the fire-stick, on which the operator stands, a foot on either end. then the slip, grasped firmly, an end in each hand, is pulled steadily back and forth, increasing gradually in pressure and velocity as the smoke comes. by the time the fire-band snaps with the friction there ought to appear through the slit in the fire-stick some incandescent dust, and this placed, smouldering as it is, in a nest of dry bamboo shavings, can be gently blown into a flame.--_the gardeners' chronicle._ * * * * * experiments in memory. when we read how one mediæval saint stood erect in his cell for a week without sleep or food, merely chewing a plantain-leaf out of humility, so as not to be too perfect; how another remained all night up to his neck in a pond that was freezing over; and how others still performed for the glory of god feats no less tasking to their energies, we are inclined to think, that, with the gods of yore, the men, too, have departed, and that the earth is handed over to a race whose will has become as feeble as its faith. but we ought not to yield to these instigations, by which the evil one tempts us to disparage our own generation. the gods have somewhat changed their shape, 'tis true, and the men their minds; but both are still alive and vigorous as ever for an eye that can look under superficial disguises. the human energy no longer freezes itself in fish-ponds, and starves itself in cells; but near the north pole, in central africa, on alpine "couloirs," and especially in what are nowadays called "psycho-physical laboratories," it maybe found as invincible as ever, and ready for every fresh demand. to most people a north pole expedition would be an easy task compared with those ineffably tedious measurements of simple mental processes of which ernst heinrich weber set the fashion some forty years ago, and the necessity of extending which in every possible direction becomes more and more apparent to students of the mind. think of making forty thousand estimates of which is the heavier of two weights, or seventy thousand answers as to whether your skin is touched at two points or at one, and then tabulating and mathematically discussing your results! insight is to be gained at no less price than this. the new sort of study of the mind bears the same relation to the older psychology that the microscopic anatomy of the body does to the anatomy of its visible form, and the one will undoubtedly be as fruitful and as indispensable as the other. dr. ebbinghaus[ ] makes an original addition to heroic psychological literature in the little work whose title we have given. for more than two years he has apparently spent a considerable time each day in committing to memory sets of meaningless syllables, and trying to trace numerically the laws according to which they were retained or forgotten. most of his results, we are sorry to say, add nothing to our gross experience of the matter. here, as in the case of the saints, heroism seems to be its own reward. but the incidental results are usually the most pregnant in this department; and two of those which dr. ebbinghaus has reached seems to us to amply justify his pains. the first is, that, in _forgetting_ such things as these lists of syllables, the loss goes on very much more rapidly at first than later on. he measured the loss by the number of seconds required to _relearn_ the list after it had been once learned. roughly speaking, if it took a thousand seconds to learn the list, and five hundred to relearn it, the loss between the two learnings would have been one-half. measured in this way, full half of the forgetting seems to occur within the first half-hour, while only four-fifths is forgotten at the end of a month. the nature of this result might have been anticipated, but hardly its numerical proportions. [footnote : "ueber das gedächtniss. untersuchungen zur experimentellen psychologie." von herm. ebbinghaus. leipzig: duncker u. humblot, . + pp. vo.] the other important result relates to the question whether ideas are recalled only by those that previously came immediately before them, or whether an idea can possibly recall another idea, with which it was never in _immediate_ contact, without passing through the intermediate mental links. the question is of theoretic importance with regard to the way in which the process of "association of ideas" must be conceived; and dr. ebbinghaus' attempt is as successful as it is original, in bringing two views, which seem at first sight inaccessible to proof, to a direct practical test, and giving the victory to one of them. his experiments conclusively show that an idea is not only "associated" directly with the one that follows it, and with the rest _through that_, but that it is _directly_ associated with _all_ that are near it, though in unequal degrees. he first measured the time needed to impress on the memory certain lists of syllables, and then the time needed to impress lists of the same syllables with gaps between them. thus, representing the syllables by numbers, if the first list was , , , ... , , , , the second would be , , ... , , , ... , and so forth, with many variations. now, if and in the first list were learned in that order merely by calling up , and by calling up , leaving out the ought to leave and with no tie in the mind; and the second list ought to take as much time in the learning as if the first list had never been heard of. if, on the other hand, has a _direct_ influence on as well as on , that influence should be exerted even when is dropped out; and a person familiar with the first list ought to learn the second one more rapidly than otherwise he could. this latter case is what actually occurs; and dr. ebbinghaus has found that syllables originally separated by as many as seven intermediaries still reveal, by the increased rapidity with which they are learned in order, the strength of the tie that the original learning established between them, over the heads, so to speak, of all the rest. it may be that this particular series of experiments is the entering wedge of a new method of incalculable reach in such questions. the future alone can show. meanwhile, when we add to dr. ebbinghaus' "heroism" in the pursuit of true averages, his high critical acumen, his modest tone, and his polished style, it will be seen that we have a new-comer in psychology from whom the best may be expected.--_w.j., science._ * * * * * sinking of the quievrechain working shaft. the sinking of mine shafts in certain belgian and french basins, where the coal deposit is covered with thick strata of watery earth, has from all times been considered as the most troublesome and delicate, and often the most difficult operation, of the miner's art. of the few modern processes that have been employed for this purpose, that of messrs. kind and chaudron has been found most satisfactory, although it leaves much to be desired where it is a question of traversing moving sand. an interesting modification of this well-known process has recently been described by mr. e. chavatte, in the bulletin de la societe industrielle du nord de la france. two years ago the author had to sink a working shaft at quievrechain, feet of which was to traverse a mass of moving and flowing sand, inconsistent earth, gravel, and marls, and proceeded as follows: he first put down two beams, a b (pl. , figs. , , and ), each feet in length and of × inch section in the center, and upon these placed two others, e f, of × inch section. beneath the two first were inserted six joists, _c c c c c c_, about feet in length and of or inch section in the center. finally these were strengthened at their extremities with two others, _d d_, about feet in length. all these timbers, having been connected by tie bands and bolts, constituted a rigid structure that covered a surface of nearly seven hundred square yards. from the beams, a b and e f, there was suspended a red fir frame by means of thirty-four iron rods. upon this frame, which was entirely immersed in the moving sand, there was established brick masonry (figs. , , and ). as the ends of the timbers entered the latter, and were connected by ½ inch bolts, they concurred in making the entire affair perfectly solid. the frame, k k, was provided with an oaken ring, which was affixed to it with bolts. after this, a cast iron tubbing, having a cutting edge, and being composed of rings . feet wide and made of six segments, was lowered. this tubbing was perfectly tight, all the surfaces of the joints having been made even and provided with strips of lead one-tenth of an inch thick. it weighed , pounds to the running foot. [illustration: fig. .--section through a b. fig. .--plan. fig. .--section through c d. fig. .--section through e f of fig. . figs. and .--work prepared and finished. fig. .--section through a b and c d of fig. . figs. and .--arrangement of jack-screw. fig. .--section through a b and c d of fig. . plate i.--sinking a mine shaft.] it was first raised to a height of fifteen feet, so as to cause it to enter the sand by virtue of its own gravity. it thus penetrated to a depth of about twenty inches. after this the workmen were ordered to man the windlasses and hoist out some of the sand. this caused the tubbing to descend about eight inches more, when it came to a standstill. it was now loaded with , pounds of pig iron, but in vain, for it refused to budge. mr. chavatte therefore had recourse to a dredge with vertical axis, constructed as follows: upon a square axis, a b (pl. , figs. , , and ), provided with double cross braces, c d, and strengthened by diagonals, were riveted, by their upper extremities, two cheeks, g h, whose lower extremities held the steel plates, i j i' j', which, in turn, were fastened to the axis, a b, by their other extremities. these plates were so inclined as to scrape the surface of the ground over which they were moved. they each carried two bags made of coarse canvas and strengthened by five strong leather straps (figs. and ). to the steel plates were riveted two plates of iron containing numerous apertures, through which passed leather straps designed for fastening thereto the lower part of the mouth of the bags. that portion of the mouth of the latter that was to remain open was fastened in the same way to two other plates, x y, x¹ y¹ (fig. ), held between the lower cross-braces. when the apparatus was revolved, the plates scraped the earth to be removed, and descended in measure as the latter entered the bags. these bags, when full, were hooked, by means of the five rings which they carried, to the device shown in fig. (pl. ), and raised to the surface and emptied into cars. the dredge was set in motion by four oak levers (figs. and ). two of these were manned by workmen stationed upon the surface flooring, and the other two by workmen upon the flooring in the tubbing. the axis was elongated, in measure as the apparatus descended, by rods of the same dimensions fastened together by cast iron sleeves and bolts (fig. ). the steel plates were not capable of acting alone, even in cases where they operated in pure moving sand containing no pebbles, for the sand was too compact to be easily scraped up by the steel, and so it had to be previously divided. for this purpose mr. chavatte used rakes which were in form exactly like those of the extirpators, u and v, of figs. , , and , of pl. , except that the dividers carried teeth that were not so strong as those of the extirpators, and that were set closer together. these rakes were let down and drawn up at will. they were maneuvered as follows: the dredge descended with the extirpators pointing upward. when their heads reached the level of the upper floor, the tools were removed. then the dredge was raised again. in this way the extirpators lay upon the floor, and, if the lifting was continued, they placed themselves in their working position, in which they were fixed by the bolts a" b" c" (fig. ). after this, the apparatus was let down and revolved. the rakes divided the earth, the scrapers collected it, and the bags pocketed it. the great difficulty was to cause the tubbing to descend vertically, and also to overcome the enormous lateral pressure exerted upon it by the earth that was being traversed. water put into the shaft helped somewhat, but the great stress to be exerted had to be effected by means of powerful jack screws. these were placed directly upon the tubbing, and bore against strong beams whose extremities were inserted into the masonry. as a usual thing it is not easy to use more than four or six such jacks, since the number of beams that can be employed is limited, owing to the danger of obstructing the mouth of the shaft. yet twelve were used by mr. chavatte, and this number might have been doubled had it been necessary. as we have seen, the frame, k k (pl. , fig. ), was provided with an oak circle traversed by bolts. the length of these latter was two inches and a quarter longer than they needed to have been, or they were provided with wooden collars of that thickness. later on, these collars were replaced with iron bars that held the wood against which the jacks bore in order to press the tubbing downward (pl. , figs. , , , and ). mr. chavatte's great anxiety was to know whether he should succeed in causing the first section of tubbing to traverse the four feet of gravel; for in case it did not pass, he would be obliged to employ a second section of smaller diameter, thus increasing the expense. he was persuaded that the coarse gravel remaining in the side of the shaft would greatly retard the descent of the tubbing. so he had decided to remove such obstructions at the proper moment through divers or a diving bell. then an idea occurred to him that dispensed with all that trouble, and allowed him to continue with the first section. this was to place upon the dredge two claw-bars, t (pl. , fig. ), which effected the operation of widening with wonderful ease. to do this it was only necessary to turn up the bags, and revolve the apparatus during its descent. the claw at the extremity of the bar pulled out everything within its reach, and thus made an absolutely free passage for the tubbing. the sands and gravels were passed by means of a single section of tubbing feet in length, which was not stopped until it had penetrated a stratum of white chalk to a depth of two yards. this chalk had no consistency, although it contained thin plates of quite large dimensions. these were cut, as if with a punch, by means of the teeth of the extirpator. it now remains to say a few words concerning the sinking of the shaft, which, after the operation of the dredge, was continued by the process called "natural level" the work was not easy until a depth of feet had been reached. up to this point it had been necessary to proceed with great prudence, and retain the shifting earth by means of four iron plate tubes weighing tons. before finding a means of widening the work already done by the dredge, mr. chavatte was certain that he would have to use two sections of tubbing, and so had given the first section a diameter of ½ feet. he could then greatly reduce the diameter, and bring it to ¾ feet as soon as the ground auger was used. after two yards of soil had been removed from beneath the edge of the tubbing, the earth began to give way. seeing this, mr. chavatte let down a tube feet in length and . in diameter. the exterior of this was provided with oak guides, which sliding over the surface of the tubbing had the effect of causing the tube to descend vertically. and this was necessary, because this tube had to be driven down every time an excavation of half a yard had been made. afterward, a diameter of . feet was proceeded with, and the small central shaft of ¼ feet diameter was begun. this latter had not as yet been sunk, for fear of causing a fall of the earth. next, the earth was excavated to a depth of . feet, and a tube . feet in length was inserted; then a further excavation of . feet was made, and the tube driven home. after this an excavation of ¼ feet was made, and a tube of the same length and ½ feet in diameter was driven down. finally, the shifting soil was finished with a fourth tube ½ feet in length and feet in diameter. a depth of feet had now been reached, and the material encountered was solid white chalk. from this point the work proceeded with a diameter of . feet to a depth of feet. the small shaft had been sunk directly to a depth of feet. at feet the diameter was diminished by three inches. then an advance of a foot was made, and the diameter reduced by one and a half inch. the reason for this reduction in the diameter and change in the mode of deepening was as follows: the chaudron moss-box, when it chances to reach its seat intact, and can consequently operate well, undoubtedly makes a good wedging. but how many times does it not happen that it gets injured before reaching its destination? besides, as it often rests upon earth that has caved in upon its seat during the descent of the tubbing, it gets askew, and later on has to be raised on one side by means of jacks or other apparatus. under such circumstances, mr. chavatte considered this moss-box as more detrimental than useful, and not at all indispensable, and so substituted beton for it, as had previously been done by mr. bourg, director of the bois-du-luc coal mines. [illustration: figs. , , , and .--details of dredge. figs. and .--details of maneuvering lever. fig. .--mode of lengthening the axis of the dredge. fig. .--hooks for lifting the dredge bags. fig. .--arrangement of valves in the beton box. fig. .--device for centering the tubbing. plate ii.] this engineer likewise suppressed the balancing column, which is often a source of trouble in the descent of the tubbing, and forced his tubbing to center itself with the shaft through a guide with four branches riveted under the false bottom that entered the small shaft (pl. , fig. ). mr. bourg so managed that there remained an empty space of ten inches to fill in with beton. mr. chavatte had at first intended to proceed in the same way, but the two last tubbings, upon which he had not counted, forced him to reduce the space to ¾ inches. under such circumstances it was not prudent to employ the same means for guiding the base of the tubbing, because, if the central shaft had not exactly the same center as the large one, there would have been danger of throwing the tubbing sideways and causing it to leak. seeing which, mr. chavatte strengthened the lower part of the base ring and placed it upon another ring tapering downward, and ½ inches in height (pl. , fig. ). the object of this lower ring was to force the tubbing to remain concentric with the shaft, to form a tight joint with its upper conical portion, and to form a joint upon the seat with its lower flange, so as to prevent the beton from flowing into the small shaft. after the shaft was pumped out, digging by hand was begun with a diameter of feet. after descending inches an × inch curb was laid, in order to consolidate the earth and prevent any movement of the tubbing. then the excavating was continued to a depth of ½ inches, and with a diameter of ¾ feet. at this point another curb was put in for consolidating the earth. finally, the bottom was widened out as shown in fig. , so that three basal wedged curbs could be put in. this done, the false tubbing was put in place; and finally, when proceeding upward, the last ring composed of twelve pieces was reached, the earth was excavated and at once replaced with a collar composed of twelve pieces of oak tightened up by oak wedges. each of these pieces was cemented separately and in measure as they were assembled. through motive of economy no masonry was placed under the base of the three wedged curbs. in fact, by replacing this with a wedged curb of wood traversed by six bolts designed to fix the cast iron curb immediately above, mr. chavatte obtained a third curb that he would have had to have made of cast iron. * * * * * on the elementary principles of the gas-engine.[ ] [footnote : a paper read before the gas institute, manchester, june, .] by denny lane, of cork. among the most useful inventions of the latter half of the nineteenth century the gas-engine holds a prominent place. while its development has not been so brilliant or so startling as that which we can note in the employment of electricity, it holds, among the applications of heat, the most important place of any invention made within that period. even amid the contrivances by which, in recent times, the other forces of nature have been subdued to the uses of man, there are only a few which rival the gas-engine in practical importance. with regard to the steam-engine itself, it is remarkable how little that is new has really been invented since the time of watt and woulfe. in the specifications of the former can be shown completely delineated, or fully foreshadowed, nearly every essential condition of the economy and efficiency attained in our own days; and it is only by a gradual "survival of the fittest" of the many contrivances which were made to carry out his broad ideas that the steam-engine of the present has attained its great economy. it is but within the last fifty years that the laws of the relation between the different physical forces were first enunciated by justice grove, and confirmed by the classical researches of dr. joule--the one a lawyer, working hard at his profession, the other a man of business engaged in manufacture. both are still living among us; the latter having withdrawn from business, while the former is a judge of the high court of justice. i always regret that the claims of his profession have weaned justice grove from science; for, while it may be possible to find in the ranks of the bar many who might worthily occupy his place on the bench, it would be hard to find among men of science any with as wide-reaching and practical philosophy as that which he owns. the chemist demonstrated long since that it was impossible for man to create or destroy a single particle of ponderable matter; but it remained for our own time to prove that it was equally impossible to create or destroy any of the energy which existed in nature as heat, mechanical power, electricity, or chemical affinity. all that it is in the power of man to do is to convert one of these forms into another. this, perhaps the greatest of all scientific discoveries since the time of newton, was first, i believe, enunciated in by grove, in a lecture given at the london institution; and it was experimentally proved by the researches of joule, described in a paper which he read at the meeting of the british association which was held at cork--my native city--in . my friend dr. sullivan, now president of queen's college, cork, and i myself had the privilege of being two of a select audience of half a dozen people, who alone took sufficient interest in the subject to hear for the first time developed the experimental proof of the theory which welds into one coherent system the whole physical forces of the universe, and enables one of these to be measured by another. one branch of the "correlation of physical forces," as it was termed by grove, was the relation between mechanical power and heat, and the convertibility of each into the other, which, under the name of "thermodynamics," has become one of the most important branches of practical science. joule's first experiments clearly proved that each of these forms of energy was convertible into the other; but some discrepancies arose in determining the exact equivalent of each. his subsequent researches, however, clearly demonstrated the true relation between both. taking as the unit of heat the amount which would be necessary to raise lb. of water ° of fahrenheit's scale (now called "the english thermal unit"), he proved that this unit was equivalent to the mechanical power which would be required to raise lb. foot, or to raise lb. ft. perpendicularly against the force of gravity. the heat-unit--the pound-degree--which i will distinguish by the greek letter [theta], is a compound unit of mass and temperature; the second--the foot-pound = f.p.--a compound unit of mass and space. this equation, called "joule's equivalent," or thermal unit = foot-pounds, is the foundation and the corner-stone of thermodynamics. it is essential to understand the meaning of this equation. it expresses the maximum effect of the given cause, viz., that if _all_ the heat were converted into power, or _all_ the power were converted into heat, thermal unit would produce foot-pounds, or foot-pounds would raise lb. of water ° fahr. but there is never a complete conversion of any form of energy. common solid coal may be partly converted into gases in a retort; but some of the carbon remains unchanged, and more is dissipated but not lost. in the same way, if i take five sovereigns to paris and convert them into francs, and return to london and convert the francs into shillings, i shall not have shillings, but only perhaps shillings. but the five shillings have not been lost; three of them remain in the french _change de monnaies_, and two of them in the english exchange office. i may have forfeited something, but the world has forfeited nothing. there remains in it exactly the same number of sovereigns, francs, and shillings as there was before i set out on my travels. nothing has been lost, but some of my money has been "dissipated;" and the analogous case, "the dissipation of energy," has formed the subject of more than one learned essay. before the invention of the steam-engine, the only powers employed in mechanics were those of wind and water mills, and animal power. in the first two, no conversion of one force into another took place; they were mere kinematic devices for employing the mechanical force already existing in the gale of wind and the head of water. with regard to the power developed by man and other animals, we had in them examples of most efficient heat-engines, converting into power a large percentage of the fuel burnt in the lungs. but animal power is small in amount, and it is expensive for two reasons--first, because the agents require long intervals of rest, during which they still burn fuel; and next, because the fuel they require is very expensive. a pound of bread or beef, or oats or beans, costs a great deal more than a pound of coal; while it does not, by its combustion, generate nearly so much heat. the steam-engine, therefore, took the place of animal power, and for a long time stood alone; and nearly all the motive power derived from heat is still produced by the mechanism which watt brought to such great efficiency in so short a time. now the practical question for all designers and employers of heat-engines is to determine how the greatest quantity of motive force can be developed from the heat evolved from a given kind of fuel; and coal being the cheapest of all, we will see what are the results obtainable from it by the steam-engine. in this we have three efficiencies to consider--those of the furnace, the boiler, and the cylinder. first, with respect to the furnace. the object is to combine the carbon and the hydrogen of the coal with a sufficient quantity of the oxygen of the air to effect complete combustion into carbonic acid and water. in order to do this, we have to use a quantity of air much larger than is theoretically necessary, and also to heat an amount of inert nitrogen five times greater than the necessary oxygen; and we are therefore obliged to create a draught which carries away to the chimney a considerable portion of the heat developed. the combustion, moreover, is never perfect; and some heat is lost by conduction and radiation. the principal loss is by hot gases escaping from the flues to the chimney. even with well-set boilers, the temperature in the chimney varies from ° to ° fahr. taking the mean of °, this would represent a large proportion of the total heat, even if the combustion were perfect; for, as a general rule, the supply of air to a furnace is double that which is theoretically necessary. for our present purpose, it will be sufficient to see how much the whole loss is, without dividing it under the several heads of "imperfect combustion," "radiation," and "convection," by the heated gases passing to the chimney. with a very good boiler and furnace each pound of coal evaporates pounds of water from ° fahr., changing it into steam of lb. pressure at a temperature of °, or ° above that of the water from which it is generated. besides these °, each pound of steam contains units of latent heat, or , units in all. a very good condensing engine will work with . lb. of coal and lb. of steam per horse power per hour. now. lb. of good coal will, by its combustion, produce , heat-units; and the . lb. of coal multiplied by , represent , [theta]. of these we find in the boiler × , , or , units, or about ½ per cent., of the whole heat of combustion; so that the difference ( , units, or ½ per cent.) has been lost by imperfect combustion, radiation, or convection. the water required for condensing this quantity of steam is lb.; and, taking the temperature in the hot well as °, lb. have been raised ° from °. thus we account for × = , , or (say) ½ per cent. still remaining as heat. if we add this ½ per cent. to ½ per cent. we have per cent., and there remain only per cent. of the heat that can possibly have been converted into power. but some of this has been lost by radiation from steam-pipes, cylinder, etc. allowing but per cent. for this, we have only per cent. as the efficiency of a really good condensing engine. this estimate agrees very closely with the actual result; for the . lb. of coal would develop , [theta]; and this, multiplied by joule's equivalent, amounts to nearly millions of foot-pounds. as horse power is a little less than million foot-pounds per hour, only one-twelfth, or a little more than per cent. of the total heat is converted; so that whether we look at the total quantity of heat which we show unconverted, or the total heat converted, we find that each supplements and corroborates the other. if we take the efficiency of the engine alone, without considering the loss caused by the boiler, we find that the , [theta] which entered the boiler should have given , , foot-pounds; so that the millions given by the engine represent about per cent. of the heat which has left the boiler. the foregoing figures refer to large stationary or marine engines, with first-rate boilers. when, however, we come to high-pressure engines of the best type, the consumption of coal is twice as much; and for those of any ordinary type it is usual to calculate cubic foot, or ½ lb., of water evaporated per horse power. this would reduce the efficiency to about per cent. for the best, and per cent. for the ordinary non-condensing engines; and if to this we add the inefficiency of some boilers, it is certain that many small engines do not convert into power more than per cent. of the potential energy contained in the coal. at one time the steam-engine was threatened with serious rivalry by the hot-air engine. about the year the rev. mr. stirling, a scotch clergyman, invented one which a member of this institute (mr. george anderson) remembers to have seen still at work at dundee. the principle of it was that a quantity of air under pressure was moved by a mass, called a "displacer," from the cold to the hot end of a large vessel which was heated by a fire beneath and cooled by a current of water above. the same air was alternately heated and cooled, expanded and contracted; and by the difference of pressure moved the piston in a working cylinder. in this arrangement the furnace was inefficient. as only a small portion of heat reached the compressed air, the loss by radiation was very great, and the wear and tear exceedingly heavy. this system, with some modifications, was revived by rankine, ericsson, laubereau, ryder, buckett, and bailey. siemens employed a similar system, only substituting steam for air. another system, originally proposed by sir george cayley, consisted in compressing by a pump cold air which was subsequently passed partly through a furnace, and, expanding, moved a larger piston at the same pressure; and the difference of the areas of the pistons multiplied by the pressure common to both represented the indicated power. this principle was subsequently developed by a very able mechanic, mr. wenham; but his engine never came much into favor. the only hot-air engines at present in use are ryder's, buckett's, and bailey's, employed to a limited extent for small powers. i have not said anything of the thermal principles involved in the construction of these engines, as they are precisely the same as those affecting the subject of the present paper. before explaining the principle upon which the gas-engine and every other hot-air engine depends, i shall remind you of a few data with which most of you are already familiar. the volume of every gas increases with the temperature; and this increase was the basis of the air thermometer--the first ever used. it is to be regretted that it was not the foundation of all others; for it is based on a physical principle universally applicable. although the volume increases with the temperature, it does not increase in proportion to the degrees of any ordinary scale, but much more slowly. now, if to each of the terms of an arithmetical series we add the same number, the new series so formed increases or decreases more slowly than the original; and it was discovered that, by adding to the degrees of fahrenheit's scale, the new scale so formed represented exactly the increment of volume caused by increase of temperature. this scale, proposed by sir w. thomson in , is called the "scale of absolute temperature." its zero, called the "absolute zero," is ° below the zero of fahrenheit, or ° below the freezing point of water; and the degree of heat measured by it is termed the "absolute temperature." it is often convenient to refer to ° fahr. (which happens to be the point at which water attains its maximum density), as this is the same as ° absolute; for, counting from this datum level, a volume of air expands exactly per cent. for °, and would be doubled at , ° absolute, or ° fahr. whenever any body is compressed, its specific heat is diminished; and the surplus portion is, as it were, pushed out of the body--appearing as sensible heat. and whenever any body is expanded, its specific heat is increased; and the additional quantity of heat requisite is, as it were, sucked in from surrounding bodies--so producing cold. this action may be compared to that of a wet sponge from which, when compressed, a portion of the water is forced out, and when the sponge is allowed to expand, the water is drawn back. this effect is manifested by the increase of temperature in air-compressing machines, and the cold produced by allowing or forcing air to expand in air-cooling machines. at ° fahr., lb. of air measures ½ cubic feet. let us suppose that lb. of air at ° fahr. = ° absolute, is contained in a non-conducting cylinder of foot area and ½ feet deep under a counterpoised piston. the pressure of the atmosphere on the piston = square inches × . lb., or , lb. if the air be now heated up to ° fahr. = , ° absolute, and at the same time the piston is not allowed to move, the pressure is doubled; and when the piston is released, it would rise ½ feet, provided that the temperature remained constant, and the indicator would describe a hyperbolic curve (called an "isothermal") because the temperature would have remained equal throughout. but, in fact, the temperature is lowered, because expansion has taken place, and the indicator curve which would then be described is called an "adiabatic curve," which is more inclined to the horizontal line when the volumes are represented by horizontal and the pressures by vertical co-ordinates. in this case it is supposed that there is no conduction or transmission (diabasis) of heat through the sides of the containing vessel. if, however, an _additional_ quantity of heat be communicated to the air, so as to maintain the temperature at , ° absolute, the piston will rise until it is ½ feet above its original position, and the indicator will describe an isothermal curve. now mark the difference. when the piston was fixed, only a heating effect resulted; but when the piston moved up ½ feet, not only a heating but a mechanical, in fact, a thermodynamic, effect was produced, for the weight of the atmosphere ( , lb.) was lifted ½ feet = , foot-pounds. the specific heat of air at constant pressure has been proved by the experiments of regnault to be . , or something less than one-fourth of that of water--a result arrived at by rankine from totally different data. in the case we have taken, there have been expended × . , or (say) . [theta] to produce , f.p. each unit has therefore produced ( , / . ) = . f.p., instead of f.p., which would have been rendered if every unit had been converted into power. we therefore conclude that ( . / ) = per cent. of the total heat has been converted. the residue, or per cent., remains unchanged as heat, and may be partly saved by a regenerator, or applied to other purposes for which a moderate heat is required. the quantity of heat necessary to raise the heat of air at a constant volume is only per cent. of that required to raise to the same temperature the same weight of air under constant pressure. this is exactly the result which laplace arrived at from observations on the velocity of sound, and may be stated thus-- specific foot- per heat. pounds. cent. kp = lb. of air at constant pressure . × = . = kv = lb. of air at constant volume . × = . = ------ --- ----- --- difference, being heat converted into power . × = . = or, in a hot-air engine without regeneration, the maximum effect of lb. of air heated ° fahr. would be . f.p. the quantity of heat ky necessary to heat air under constant volume is to kv, or that necessary to heat it under constant pressure, as : , or as : . , or very nearly as :sqrt( )--a result which was arrived at by masson from theoretical considerations. the per cent. escaping as heat may be utilized in place of other fuel; and with the first hot-air engine i ever saw, it was employed for drying blocks of wood. in the same way, the unconverted heat of the exhaust steam from a high-pressure engine, or the heated gases and water passing away from a gas-engine, may be employed. [illustration] we are now in a position to judge what is the practical efficiency of the gas-engine. some years since, in a letter which i addressed to _engineering_, and which also appeared in the _journal of gas lighting_,[ ] i showed (i believe for the first time) that, in the otto-crossley engine, per cent. of the total heat was converted into power, as against the per cent. given by a very good steam-engine. about the end of a very elaborate essay, by m. witz, appeared in the _annales de chimie et de physique_, reporting experiments on a similar engine, which gave an efficiency somewhat lower. early in there appeared in _van nostrand's engineering magazine_ a most valuable paper, by messrs. brooks and steward, with a preface by professor thurston,[ ] in which the efficiency was estimated at to per cent. of the total heat of combustion. both these papers show what i had no opportunity of ascertaining, that is, what becomes of the per cent. of heat which is not utilized--information of the greatest importance, as it indicates in what direction improvement may be sought for, and how loss may be avoided. but, short as is the time that has elapsed since the appearance of these papers, you will find that progress has been made, and that a still higher efficiency is now claimed. [footnote : see _journal_, vol. xxxv, pp. , .] [footnote : ibid., vol. xliii., pp. , .] when i first wrote on this subject, i relied upon some data which led me to suppose that the heating power of ordinary coal gas was higher than it really is. at our last meeting, mr. hartley proved, by experiments with his calorimeter, that gas of or candles gave only about units of heat per cubic foot. now, if all this heat could be converted into power, it would yield × , or , f.p.; and it would require only , , / , = . cubic feet to produce indicated horse power. some recent tests have shown that, with gas of similar heating power, cubic feet have given indicated horse power, and therefore . / = . of the whole heat has been converted--a truly wonderful proportion when compared with steam-engines of a similar power, showing only an efficiency of to per cent. the first gas-engine which came into practical use was lenoir's, invented about , in which the mixture of gas and air drawn in for part of the stroke at atmospheric pressure was inflamed by the spark from an induction coil. this required a couple of cells of a strong bunsen battery, was apt to miss fire, and used about cubic feet of gas per horse power. this was succeeded by hugon's engine, in which the ignition was caused by a small gas flame, and the consumption was reduced to cubic feet. in otto's atmospheric engine was invented, in which a heavily-loaded piston was forced upward by an explosion of gas and air drawn in at atmospheric pressure. in its upward stroke the piston was free to move; but in its downward stroke it was connected with a ratchet, and the partial vacuum formed after the explosion beneath the piston, together with its own weight in falling, operated through a rack, and caused rotation of the flywheel. this engine (which, in an improved form, uses only about cubic feet of gas) is still largely employed, some , having been constructed. the great objection to it was the noise it produced, and the wear and tear of the ratchet and rack arrangements. in the otto-crossley silent engine was introduced. as you are aware, it is a single-acting engine, in which the gas and air are drawn in by the first outward, and compressed by the first inward stroke. the compressed mixture is then ignited; and, being expanded by heat, drives the piston outward by the second outward stroke. near the end of this stroke the exhaust-valve is opened, the products of combustion partly escape, and are partly driven out by the second inward stroke. i say partly, for a considerable clearance space, equal to per cent. of the whole cylinder volume, remains unexhausted at the inner end of the cylinder. when working to full power, only one stroke out of every four is effective; but this engine works with only to cubic feet of gas per horse power. up to the present time i am informed that about , of these engines have been manufactured. several other compression engines have been introduced, of which the best known is mr. dugald clerk's, using about feet of glasgow cannel gas. it gives one effective stroke for every revolution; the mixture being compressed in a separate air-pump. but this arrangement leads to additional friction; and the power measured by the brake is a smaller percentage of the indicated horse power than in the otto-crossley engine. a number of gas engines--such as bisschop's (much used for very small powers), robson's (at present undergoing transformation in the able hands of messrs. tangye), korting's, and others--are in use; but, so far as i can learn, all require a larger quantity of gas than those previously referred to. [illustration: otto atmospheric gas engine.] [illustration: clerck's gas engine, horse power.] [illustration: otto-crossley gas engine, h.p. consumption . cubic feet of -candle gas per theoretical horse power per hour. average pressure, . × constant, . theoretical horse power per pound = . theoretical horse power.] [illustration: atkinson's differential gas engine, h.p.] i have all along spoken of efficiency as a percentage of the total quantity of heat evolved by the fuel; and this is, in the eyes of a manufacturer, the essential question. other things being equal, that engine is the most economical which requires the smallest quantity of coal or of gas. but men of science often employ the term efficiency in another sense, which i will explain. if i wind a clock, i have spent a certain amount of energy lifting the weight. this is called "energy of position;" and it is returned by the fall of the weight to its original level. in the same way if i heat air or water, i communicate to it energy of heat, which remains potential as long as the temperature does not fall, but which can be spent again by a decrease of temperature. in every heat-engine, therefore, there must be a fall from a higher to a lower temperature; otherwise no work would be done. if the water in the condenser of a steam-engine were as hot as that in the boiler, there would be equal pressure on both sides of the piston, and consequently the engine would remain at rest. now, the greater the fall, the greater the power developed; for a smaller proportion of the heat remains as heat. if we call the higher temperature t and the lower t' on the absolute scale, t - t' is the difference; and the ratio of this to the higher temperature is called the "efficiency." this is the foundation of the formula we meet so often: e = (t - t')/t. a perfect heat-engine would, therefore, be one in which the temperature of the absolute zero would be attained, for (t - o)/t = . this low temperature, however, has never been reached, and in all practical cases we are confined within much narrower limits. taking the case of the condensing engine, the limits were ° to °, or ° and ° absolute, respectively. the equation then becomes ( - )/ = / or (say) per cent. with non-condensing engines, the temperatures may be taken as ° and °, or ° and ° absolute respectively. the equation then becomes ( - )/ = / , or nearly per cent. the practical efficiencies are not nearly this, but they are in about the same ratio-- / . if, then, we multiply the theoretical efficiencies by . , we get the practical efficiencies, say per cent. and per cent.; and it is in the former sense that m. witz calculated the efficiency of the steam-engine at per cent.--a statement which, i own, puzzled me a little when i first met it. these efficiencies do not take any account of loss of heat before the boiler. in the case of the gas-engine, the question is much more complicated on account of the large clearance space and the early opening of the exhaust. the highest temperature has been calculated by the american observers at , ° absolute, and the observed temperature of the exhaust gases was , °. the fraction then becomes ( - )/ = per cent. if we multiply this by . , as we did in the case of the steam-engine, we get . per cent., or approximately the same as that arrived at by direct experience. indeed, if the consumption is, as sometimes stated, less than feet, the two percentages would be exactly the same. i do not put this forward as scientifically true; but the coincidence is at least striking. i have spoken of the illuminating power of the gas as of importance; for the richer gases have also more calorific power, and an engine would, of course, require a smaller quantity of them. the heat-giving power does not, however, vary as the illuminating power, but at a much slower rate; and, adopting the same contrivance as that on which the absolute scale of temperature is formed, i would suggest a formula of the following type: h = c (i + k), in which h represents the number of heat-units given out by the combustion of cubic foot of gas, i is the illuminating power in candles, and c and k two constants to be determined by experiment. if we take the value for motive power of the different qualities of gas as given in mr. charles hunt's interesting paper in our transactions for , c might without any great error be taken as and k as . . with pintsch's oil gas, however, as compared with coal gas, this formula does not hold; and c should be taken much lower, and k much higher than the figures given above. that is to say, the heating power increases in a slower progression. the data available, however, are few; but i trust that mr. hartley will on this, as he has done on so many other scientific subjects, come to our aid. i will now refer to the valuable experiments of messrs. brooks and steward, which were most carefully made. everything was measured--the gas by a light, and the air by a light meter; the indicated horse power, by a steam-engine indicator; the useful work, by a prony brake; the temperature of the water, by a standard thermometer; and that of the escaping gases, by a pyrometer. the gas itself was analyzed; and its heating power calculated, from its composition, as . [theta]. its specific gravity was . ; and the volume of air was about seven times that of the gas used (or one-eighth of the mixture), and was only ½ per cent. by weight more than was needed for perfect combustion. the results arrived at were as follows: per cent. converted into indicated horse power, including friction, etc. . escaped with the exhaust gas. . escaped in radiation. . communicated to water in the jacket. . it will thus be seen that more than half of the heat is communicated to the water in the jacket. now, this is the opposite of the steam-engine, where the jacket is used to transmit heat _to_ the cylinder, and not _from_ it. this cooling is rendered necessary, because without it the oil would be carbonized, and lubrication of the cylinder rendered impossible. indeed, a similar difficulty has occurred with all hot-air engines, and is, i think, the reason they have not been more generally adopted. i felt this so strongly that, for some time after the introduction of the gas-engine, i was very cautious in recommending those who consulted me to adopt it. i was afraid that the wear and tear would be excessive. i have, however, for some time past been thoroughly satisfied that this fear was needless; as i am satisfied that a well-made gas-engine is as durable as a steam-engine, and the parts subject to wear can be replaced at moderate cost. we have no boiler, no feed pump, no stuffing-boxes to attend to--no water-gauges, pressure-gauges, safety-valve, or throttle-valve to be looked after; the governor is of a very simple construction; and the slide-valves may be removed and replaced in a few minutes. an occasional cleaning out of the cylinder at considerable intervals is all the supervision that the engine requires. the very large percentage of heat absorbed by the water-jacket should point out to the ingenuity of inventors the first problem to be attacked, viz., how to save this heat without wasting the lubricant or making it inoperative; and in the solution of this problem, i look for the most important improvement to be expected in the engine. the most obvious contrivance would be some sort of intercepting shield, which would save the walls of the cylinder and the rings of the piston from the heat of the ignited gases. i have just learned that something of the kind is under trial. another solution may possibly be found in the employment of a fluid piston; but here we are placed in a dilemma between the liquids that are decomposed and the metals that are oxidized at high temperatures. next, the loss by radiation-- per cent.--seems large; but this is to be attributed to the fact that the inside surface of the cylinder is at each inward stroke exposed to the atmosphere--an influence which contributes to the cooling necessary for lubrication. the remaining per cent., which is carried away by the exhaust, is small compared with the proportion passing away with the exhaust steam of a high-pressure or the water of a condensing engine. as the water in the jacket can be safely raised to ° fahr., the whole of the jacket heat can be utilized where hot water is required for other purposes; and this, with the exhaust gases, has been used for drying and heating purposes. with such advantages, it may be asked: why does not the gas-engine everywhere supersede the steam-engine? my answer is a simple one: the gas we manufacture is a dear fuel compared with coal. ordinary coal gas measures cubic feet to the pound; and , cubic feet, therefore, weigh lb. taking the price at s. d. per , cubic feet, it costs d. per lb. the cubic feet at [theta] give , [theta] all available heat. although good coal may yield , units by its combustion, only about , of these reach the boiler; so that the ratio of the useful heat is / . the thermal efficiency of the best non-condensing engine to that of the gas-engine is in the ratio / . multiplying together these two ratios, we get -- x ------- = ---- _{ / } . that is, speaking roughly, lb. of gas gives about ten times as much power as lb. of coal does in a good non-condensing engine. but at s. d. a ton we get lb. of coal for d.; so that with these figures the cheapness of the coal would just compensate for the efficiency of the gas. as to the waste heat passing away from the engine being utilized, here the gas-engine has no advantage; and, so far as this is concerned, the gas is about eight times dearer than coal. the prices of gas and coal vary so much in different places that it is hard to determine in what cases gas or coal will be the dearer fuel, considering this point alone. but there are other kinds of non-illuminating gases--such as wilson's, strong's, and dowson's--which are now coming into use; and at messrs. crossley's works you will have an opportunity of seeing a large engineering factory employing several hundred mechanics, and without a chimney, in which every shaft and tool is driven by gas-engines supplied by dowson's gas, and in which the consumption of coal is only . lb. per indicated horse power. the greatest economy ever claimed for the steam-engine was a consumption of . lb.; and this with steam of very high pressure, expanded in three cylinders successively. thus in a quarter of a century the gas-engine has beaten in the race the steam-engine; although from watt's first idea of improvement, nearly a century and a quarter have elapsed. as regards the steam-engine, it is the opinion of competent authorities that the limits of temperature between which it works are so restricted, and so much of the heat is expended in producing a change of state from liquid to vapor, that little further improvement can be made. with respect to gas-engines, the limits of temperature are much further apart. a change of state is not required, and so very great improvement may still be looked for. it is not impossible even that some of the younger members of our body may live to see that period foretold by one of the greatest of our civil engineers--that happy time when boiler explosions will only be matters of history; that period, not a millennium removed by a thousand years, but an era deferred perhaps by only half a dozen decades, when the use of the gas-engine will be universal, and "a steam-engine can be found only in a cabinet of antiquities." _discussion._ the president said this was a very delightful paper; and nothing could be finer than mr. lane's description of the conversion of heat into power, and the gradual growth of theory into practical work. mr. w. foulis (glasgow) agreed that it was admirable; but it required to be read to be thoroughly appreciated. when members were able to read it, they would find mr. lane had given a very clear description of the elementary principles of thermo-dynamics in their relation to the gas-engine and the steam-engine. there was very little in the paper to raise discussion; but mr. lane had made exceedingly clear how the present loss in a gas-engine was occasioned, and had also shown how, in the future development of the engine, the loss might be saved, and the engine rendered more efficient. mr. h.p. holt (of messrs. crossley bros., limited) said he could indorse everything mr. lane had said. he had found the paper most interesting and instructive even to himself, though he had some little practical experience of gas-engines, and was supposed to know a little about them. he did not pretend to be able to teach other people; but if he could say anything as to indicator cards, or answer any questions, he should be happy to do so. (he then described the indicator diagram of the atmospheric gas-engine.) in this engine the proportion of the charging stroke to the whole sweep of the piston was about per cent.; and as the charge drawn in consisted of about per cent. of gas, about - of the total sweep of the piston was composed of the gas. mr. foulis asked what proportion the power indicated on the diagram bore to the power indicated on the brake in the atmospheric engine. mr. holt said unfortunately he had not any figures with him which would give this information; and it was so long since he had anything practically to do with this form of engine, that he should not like to speak from memory. he might add that the largest size of gas-engine made (of about horse power indicated) was at work at messrs. edwin butterworth and co.'s, of manchester. it was now driven by ordinary coal gas; but dowson plant was to be put up very shortly in order to reduce the cost of working, which, though not excessive, would be still more economical with the dowson gas--probably only about s. per week. the present cost was about £ per week, though it was not working always at full power. mr. t. holgate (batley) said he thought it was generally understood, by those who had studied the subject, that the adoption of compression of the gaseous mixture before ignition had, so far, more than anything else, contributed to the improved working of gas-engines. this fact had not been sufficiently brought out in the paper, although mr. lane had clearly indicated some of the directions in which further improvements were likely to obtain. gas engineers were largely indebted to mr. dugald clerk for the statement he had made of the theory of the gas-engine.[ ] mr. lane had given some figures, arrived at by messrs. brooks and steward, from experiments made in america; but, prior to these mr. clerk had given others which were in the main in accordance with them. professor kennedy had also made experiments, the results of which agreed with them.[ ] the extent of the loss by the cooling water was thus well ascertained; and it was no doubt by a reduction of this loss that further improvement in the working of gas-engines would eventually be obtained. [footnote : see journal, vol. xxxix., p. .] [footnote : ibid., vol. xl., p. .] mr. j. paterson (warrington) expressed his appreciation of the paper, as one of exceptional interest and value. he said he did not rise with a view to make any observations thereon. the analysis of first principles required more matured consideration and thought than could be given to it here. the opinion, however, he had formed of the paper placed it beyond the reach of criticism. it was now many years since his attention had been drawn to the name of denny lane; and everything that had come from his facile pen conveyed sound scientific conclusions. the paper to which they had just listened was no exception. it was invested with great interest, and would be regarded as a valuable contribution to the transactions of the institute. mr. lane, in reply, thanked the members for the kind expressions used with respect to his paper. his object in writing it was that any one who had not paid any attention to the subject before should be able to understand thoroughly the principles on which gas and hot-air engines operated; and he believed any one who read it with moderate care would perfectly understand all the essential conditions of the gas-engine. he might mention that not long after the thermo-dynamic theory was so far developed as to determine the amount of heat converted into power, a very eminent french engineer--m. hirn--conducted some experiments on steam-engines at a large factory, and thought he could account for the whole heat of combustion in the condensed water and the heat which passed away; so much so that he actually doubted altogether the theory of thermo-dynamics. however, being open to conviction, he made further experiments, and discovered that he had been in error, and ultimately became one of the most energetic supporters of the theory. this showed how necessary it was to be careful before arriving at a conclusion on such a subject. he had endeavored, as far as the nature of the case allowed, to avoid any scientific abstractions, because he knew that when practical men came to theory--_x's_ and _y's_, differentials, integrals, and other mathematical formulæ--they were apt to be terrified. the president said it was like coming down to every day life to say that it was important that gas managers should be familiar with the appliances used in the consumption of gas, and should be able, when called upon, to give an intelligent description of their method of working. a study of mr. lane's paper would reveal many matters of interest with regard to this wonderful motor, which was coming daily more and more into use, not only to the advantage of gas manufacturers, but of those who employed them. * * * * * m. meizel's reciprocating exhauster. at the recent congress of the societe technique de l'industrie du gaz en france, m. meizel, chief engineer of the st. etienne gas works, described a new exhauster devised by him on the reciprocating principle, and for which he claims certain advantages over the appliances now in general use. exhausters constructed on the above-named principle have hitherto, m. meizel says, been costly to fit up, owing to the necessity for providing machinery and special mechanism for the transmission of motion. this has prevented the employment of cylinders of large dimensions; and, consequently, when the quantity of gas to be dealt with has been considerable, the number of exhausters has had to be increased. the result of this has been inconvenience, which has led to a preference being shown for other kinds of exhausters, notwithstanding the manifest advantages which, in m. meizel's opinion, those of the reciprocating type possess. the improvement which he has effected in these appliances consists in the application to them of cylinders working automatically; and the general features of the arrangement are shown in the accompanying illustrations. [illustration: improved reciprocating gas exhauster.] the principal advantages to be gained by the use of this exhauster are stated by m. meizel to be the following: considerably less motive force is necessary than is the case with other exhausters, which require steam engines and all the auxiliary mechanism for the transmission of power. by its quiet and regular action, it prevents oscillation and unsteadiness in the flow of gas in the hydraulic main, as well as in the pipes leading therefrom--a defect which has been found to exist with other exhausters. the bells, being of large area, serve the purpose of a condenser; and as, owing to its density, the tar falls to the bottom of the lower vessels, which are filled with water, contact between the gas and tar is avoided. although the appliance is of substantial construction, its action is so sensitive that it readily adapts itself to the requirements of production. it may be placed in the open air; and therefore its establishment is attended with less outlay than is the case with other exhausters, which have to be placed under cover, and provided with driving machinery and, of course, a supply of steam. the total superficial area of the exhauster above described, including the governor, is square feet; and its capacity per hours is , cubic feet. it works silently, with an almost entire absence of friction; and consequently there are few parts which require lubrication. exhausters of this type (which, m. meizel says, could be made available for ventilation purposes, in case of necessity) may be constructed of all sizes, from cubic feet per hour upward. * * * * * automatic siphon for irrigation. when, at an elevated point in a meadow, there exists a spring or vein of water that cannot be utilized at a distance, either because the supply is not sufficient, or because of the permeability of the soil, it becomes very advantageous to accumulate the water in a reservoir, which may be emptied from time to time through an aperture large enough to allow the water to flow in abundance over all parts of the field. [illustration: giral's automatic siphon.] the storing up of the water permits of irrigating a much greater area of land, and has the advantage of allowing the watering to be effected intermittingly, this being better than if it were done continuously. but this mode of irrigating requires assiduous attention. it is necessary, in fact, when the reservoir is full, to go and raise the plug, wait till the water has flowed out, and then put in the plug again as accurately as possible--a thing that it is not always easy to do. the work is a continuous piece of drudgery, and takes just as much the longer to do in proportion as the reservoir is more distant from one's dwelling. in order to do away with this inconvenience, mr. giral, of langogne (lozere), has invented a sort of movable siphon that primes itself automatically, however small be the spring that feeds the reservoir in which it is placed. the apparatus (see figure) consists of an elbowed pipe, c a b d e, of galvanized iron, whose extremity, c, communicates with the outlet, r, where it is fixed by means of a piece of rubber of peculiar form that allows the other extremity, b d e, to revolve around the axis, k, while at the same time keeping the outlet pipe hermetically closed. this rubber, whose lower extremity is bent back like the bell of a trumpet, forms a washer against which there is applied a galvanized iron ring that is fixed to the mouth of the outlet pipe by means of six small screws. this ring is provided with two studs which engage with two flexible thimbles, k and l, that are affixed to the siphon by four rivets. these studs and thimbles, as well as the screws, are likewise galvanized. between the branches, a b d e, of the pipe there is soldered a sheet of galvanized iron, which forms isolatedly a receptacle or air-chamber, f, that contains at its upper part a small aperture, _b_, that remains always open, and, at its lower part, a copper screw-plug, _d_, and a galvanized hook, h. in the interior of this chamber there is arranged a small leaden siphon, _a b c_, whose longer leg, _a_, passes through the bottom, where it is soldered, and whose shorter one, _c_, ends in close proximity to the bottom. finally, a galvanized iron chain, g h, fixed at g to the bottom of the reservoir, and provided with a weight, p, of galvanized iron, is hooked at h to the siphon and allows it to rise more or less, according as it is given a greater or less length. from what precedes, it will be seen that the outlet is entirely closed, so that, in order that the water may escape, it must pass into the pipe in the direction, e d b a c. this granted, let us see how the apparatus works: in measure as the water rises in the reservoir, the siphon gradually loses weight, and its extremity, b d h, is finally lifted by the thrust, so that the entire affair revolves upon the studs, k, until the chain becomes taut. the apparatus then ceases to rise; but the water, ever continuing to rise, finally reaches the apex, _b_, of the smaller siphon, and, through it, enters the air chamber and fills it. the equilibrium being thus broken, the siphon descends to the bottom, becomes primed, and empties the reservoir. when the level of the water, in descending, is at the height of the small siphon, _a b c_, this latter, which is also primed, empties the chamber, f, in turn, so that, at the moment the large siphon loses its priming, the entire apparatus is in the same state that it was at first. in short, when the water enters the reservoir, the siphon, movable upon its base, rises to the height at which it is desired that the flow shall take place. being arrested at this point by the chain, it becomes primed, and sinks, and the water escapes. when the water is exhausted, the siphon rises anew in order to again sink; and this goes on as long as the period of irrigation lasts. this apparatus, which is simple in its operation, and not very costly, is being employed with success for irrigating several meadows in the upper basin of the allier.--_le genie civil._ * * * * * assay of earthenware glaze. lead oxide melted or incompletely vitrified is still in common use in the manufacture of inferior earthenware, and sometimes leads to serious results. to detect lead in a glaze, m. herbelin moistens a slip of white linen or cotton, free from starch, with nitric acid at per cent. and rubs it for ten to fifteen seconds on the side of the utensil under examination, and then deposits a drop of a solution of potassium iodide, at per cent. on the part which has been in contact. a lead glaze simply fused gives a very highly colored yellow spot of potassium iodide; a lead glaze incompletely vitrified gives spots the more decided, the less perfect the vitrification; and a glaze of good quality gives no sensible color at all.--_m. herbelin._ * * * * * on the electrical furnace and the reduction of the oxides of boron, silicon, aluminum, and other metals by carbon.[ ] [footnote : read at the recent meeting of the american association, ann arbor, mich.] by eugene h. cowles, alfred h. cowles, and charles f. mabery. the application of electricity to metallurgical processes has hitherto been confined to the reduction of metals from solutions, and few attempts have been made to effect dry reductions by means of an electric current. sir w. siemens attempted to utilize the intense heat of an electric arc for this purpose, but accomplished little beyond fusing several pounds of steel. a short time since, eugene h. cowles and alfred h. cowles of cleveland conceived the idea of obtaining a continuous high temperature on an extended scale by introducing into the path of an electric current some material that would afford the requisite resistance, thereby producing a corresponding increase in the temperature. after numerous experiments that need not be described in detail, coarsely pulverized carbon was selected as the best means for maintaining a variable resistance and at the same time as the most available substance for the reduction of oxides. when this material, mixed with the oxide to be reduced, was made a part of the electric circuit in a fire clay retort, and submitted to the action of a current from a powerful dynamo machine, not only was the oxide reduced, but the temperature increased to such an extent that the whole interior of the retort fused completely. in other experiments lumps of lime, sand, and corundum were fused, with indications of a reduction of the corresponding metal; on cooling, the lime formed large, well-defined crystals, the corundum beautiful red, green, and blue hexagonal crystals. following up these results with the assistance of charles f. mabery, professor of chemistry in the case school of applied science, who became interested at this stage of the experiments, it was soon found that the intense heat thus produced could be utilized for the reduction of oxides in large quantities, and experiments were next tried on a large scale with a current from two dynamos driven by an equivalent of fifty horse power. for the protection of the walls of the furnace, which were made of fire brick, a mixture of the ore and coarsely pulverized gas carbon was made a central core, and it was surrounded on the sides and bottom by fine charcoal, the current following the lesser resistance of the central core from carbon electrodes which were inserted at the ends of the furnace in contact with the core. in order to protect the machines from the variable resistance within the furnace, a resistance box consisting of a coil of german silver wire placed in a large tank of water was introduced into the main circuit, and a brush ammeter was also attached by means of a shunt circuit, to indicate the quantity of current that was being absorbed in the furnace. the latter was charged by first filling it with charcoal, making a trough in the center, and filling this central space with the ore mixture, which was covered with a layer of coarse charcoal. the furnace was closed at the top with fire brick slabs containing two or three holes for the escape of the gaseous products of the reduction, and the entire furnace made air-tight by luting with fire clay. within a few minutes after starting the dynamo, a stream of carbonic oxide issued through the openings, burning usually with a flame eighteen inches in height. the time required for complete reduction was ordinarily about an hour. the furnace at present in use is charged in substantially the same manner, and the current is supplied by a brush machine of variable electromotive force driven by an equivalent of forty horse power. a brush machine capable of utilizing horse power, or two and one-half times as large as any hitherto constructed by the brush electric company, is being made for the cowles electric smelting and aluminum company, and this machine will soon be in operation. experiments already made so that aluminum, silicon, boron, manganese, magnesium, sodium and potassium can be reduced from their oxides with ease. in fact, there is no oxide that can withstand temperatures attainable in this electrical furnace. charcoal is changed to graphite. does this indicate fusion or solution of carbon? as to what can be accomplished by converting enormous electrical energy into heat within a limited space, it can only be said that it opens the way into an extensive field for both pure and applied chemistry. it is not difficult to conceive of temperatures limited only by the capability of carbon to resist fusion. the results to be obtained with the large brush machine above mentioned will be of some importance in this direction. since the cost of the motive power is the chief expense in accomplishing reductions by this method, its commercial success is closely connected with the cheapest form of power to be obtained. realizing the importance of this point, the cowles electric smelting and aluminum company has purchased an extensive and reliable water power, and works are soon to be erected for the utilization of , horse power. an important feature in the use of these furnaces, from a commercial standpoint, is the slight technical skill required in their manipulation. the four furnaces in operation in the experimental laboratory at cleveland are in charge of two young men twenty years of age, who, six months ago, knew absolutely nothing of electricity. the products at present manufactured are the various grades of aluminum bronze made from a rich furnace product that is obtained by adding copper to the charge of ore, silicon bronze prepared in the same manner, and aluminum silver, an alloy of aluminum with several other metals. a boron bronze may be prepared by the reduction of boracic acid in contact with copper. as commercial results may be mentioned the production in the experimental laboratory, which averages fifty pounds of per cent. aluminum bronze daily, and it can be supplied to the trade in large quantities at prices based on $ per pound for the aluminum contained, the lowest market quotation of this metal being at present $ per pound. silicon bronze can be furnished at prices far below those of the french manufacturers. the alloys which the metals obtained by the methods above described form with copper have been made the subject of careful study. an alloy containing per cent. of aluminum and per cent. of copper forms the so-called aluminum bronze with a fine golden color, which it retains for a long time. the tensile strength of this alloy is usually given as , pounds to the square inch; but castings of our ten per cent. bronze have stood a strain of , pounds. it is a very hard, tough alloy, with a capacity to withstand wear far in excess of any other alloy in use. all grades of aluminum bronze make fine castings, taking very exact impressions, and there is no loss in remelting, as in the case of alloys containing zinc. the per cent. aluminum alloy is a close approximation in color to carat gold, and does not tarnish readily. its tensile strength in the form of castings is equivalent to a strain of , pounds to the square inch. an alloy containing or per cent. aluminum is stronger than brass, possesses greater permanency of color, and would make an excellent substitute for that metal. when the percentage of aluminum reaches , an exceedingly hard, brittle alloy of a reddish color is obtained, and higher percentages increase the brittleness, and the color becomes grayish-black. above per cent. the strength again increases. the effect of silicon in small proportions upon copper is to greatly increase its tensile strength. when more than per cent. is present, the product is exceedingly brittle and grayish-black in color. it is probable that silicon acts to a certain extent as a fluxing material upon the oxides present in the copper, thereby making the metal more homogeneous. on account of its superior strength and high conductivity for electrical currents, silicon bronze is the best material known for telegraph and telephone wire. the element boron seems to have almost as marked an effect upon copper as carbon does upon iron. a small percentage in copper increases its strength to , or , pounds per square inch without diminishing to any large extent its conductivity. aluminum increases very considerably the strength of all metals with which it is alloyed. an alloy of copper and nickel containing a small percentage of aluminum, called hercules metal, withstood a strain of , pounds, and broke without elongation. another grade of this metal broke under a strain of , pounds, with an elongation equivalent to per cent. it must be remembered that these tests were all made upon castings of the alloys. the strength of common brass is doubled by the addition of or per cent. of aluminum. alloys of aluminum and iron are obtained without difficulty; one product was analyzed, containing per cent. of aluminum. in the furnace iron does not seem to be absorbed readily by the reduced aluminum when copper is present; but in one experiment a mixture composed of old files, per cent.; nickel, per cent.; and of per cent. aluminum bronze per cent., was melted together, and it gave a malleable product that stood a strain of , pounds. when the reduction of aluminic oxide by carbon is conducted without the addition of copper, a brittle product is obtained that behaves in many respects like pig iron as it comes from the blast furnace. the same product is formed in considerable quantities, even when copper is present, and frequently the copper alloy is found embedded in it. graphite is always found associated with it, even when charcoal is the reducing material, and analysis invariably shows a very high percentage of metallic aluminum. this extremely interesting substance is at present under examination. * * * * * the cowles electric smelting process. the use of electricity in the reduction of metals from their ores is extending so rapidly, and the methods of its generation and application have been so greatly improved within a few years, that the possibility of its becoming the chief agent in the metallurgy of the future may now be admitted, even in cases where the present cost of treatment is too high to be commercially advantageous. the refining of copper and the separation of copper, gold, and silver by electrolysis have thus far attracted the greatest amount of attention, but a commercial success has also been achieved in the dry reduction by electricity of some of the more valuable metals by the cowles electric smelting and aluminum company, of cleveland, ohio. both this method of manufacture and the qualities of the products are so interesting and important that it is with pleasure we call attention to them as steps toward that large and cheap production of aluminum that the abundance of its ores and the importance of its physical properties have for several years made the unattained goal of many skillful metallurgists. the messrs. cowles have succeeded in greatly reducing the market value of aluminum and its alloys, and thereby vastly extending its uses, and they are now by far the largest producers in the world of these important products. as described in their patents, the cowles process consists essentially in the use for metallurgical purposes of a body of granular material of high resistance or low conductivity interposed within the circuit in such a manner as to form a continuous and unbroken part of the same, which granular body, by reason of its resistance, is made incandescent, and generates all the heat required. the ore or light material to be reduced--as, for example, the hydrated oxide of aluminum, alum, chloride of sodium, oxide of calcium, or sulphate of strontium--is usually mixed with the body of granular resistance material, and is thus brought directly in contact with the heat at the points of generation, at the same time the heat is distributed through the mass of granular material, being generated by the resistance of all the granules, and is not localized at one point or along a single line. the material best adapted for this purpose is electric light carbon, as it possesses the necessary amount of electrical resistance, and is capable of enduring any known degree of heat when protected from oxygen without disintegrating or fusing; but crystalline silicon or other equivalent of carbon can be employed for the same purpose. this is pulverized or granulated, the degree of granulation depending upon the size of the furnace. coarse granulated carbon works better than finely pulverized carbon, and gives more even results. the electrical energy is more evenly distributed, and the current can not so readily form a path of highest temperature, and consequently of least resistance through the mass along which the entire current or the bulk of the current can pass. the operation must necessarily be conducted within an air-tight chamber or in a non-oxidizing atmosphere, as otherwise the carbon will be consumed and act as fuel. the carbon acts as a deoxidizing agent for the ore or metalliferous material treated, and to this extent it is consumed, but otherwise than from this cause, it remains unimpaired. fig. i. of the accompanying drawings is a vertical longitudinal section through a retort designed for the reduction of zinc ore, according to this process, and fig. ii. is a front elevation of the same. fig. iii. is a perspective view of a furnace adapted to withstand a very high temperature, and figs. iv. and v. are respectively longitudinal and transverse sections of the same. [illustration: the cowles electric smelting process.] this retort consists of a cylinder, a, made of silica or other non-conducting material, suitably embedded in a body, b, of powdered charcoal, mineral wool, or of some other material which is not a good conductor of heat. the rear end of the retort-cylinder is closed by means of a carbon plate, c, which plate forms the positive electrode, and with this plate the positive wire of the electric circuit is connected. the outer end of the retort is closed by means of an inverted graphite crucible, d, to which the negative wire of the electric circuit is attached. the graphite crucible serves as a plug for closing the end of the retort. it also forms a condensing chamber for the zinc fumes, and it also constitutes the negative electrode. the term "electrode" is used in this case as designating the terminals of the circuit proper, or that portion of it which acts simply as an electrical conductor, and not with the intention of indicating the ends of a line between which there is no circuit connection. the circuit between the "electrodes," so called, is continuous, being established by means of and through the body of broken carbon contained in the retort, a. there is no deposit made on either plate of the decomposed constituents of the material reduced. the mouth of the crucible is closed with a luting of clay, or otherwise, and the opening, _d_, made in the upper side of the crucible, near its extremity, comes entirely within the retort, and forms a passage for the zinc fumes from the retort chamber into the condensing chamber. the pipe, e, serves as a vent for the condensing chamber. the zinc ore is mixed with pulverized or granular carbon, and the retort charged nearly full through the front end with the mixture, the plug, d, being removed for this purpose. a small space is left at the top, as shown. after the plug has been inserted and the joint properly luted, the electric circuit is closed and the current allowed to pass through the retort, traversing its entire length through the body of mixed ore and carbon. the carbon constituents of the mass become incandescent, generating a very high degree of heat, and being in direct contact with the ore, the latter is rapidly and effectually reduced and distilled. the heat evolved reduces the ore and distills the zinc, and the zinc fumes are condensed in the condensing chamber, precisely as in the present method of zinc making, with this important exception that, aside from the reaction produced by heating carbon in the presence of zinc oxide, the electric current, in passing through the zinc oxide, has a decomposing and disintegrating action upon it, not unlike the effect produced by an electric current in a solution. this action accelerates the reduction, and promotes economy in the process. another form of furnace is illustrated by fig. iii., which is a perspective view of a furnace adapted for the reduction of ores and salts of non-volatile metals and similar chemical compounds. figs. iv. and v. are longitudinal and transverse sections, respectively, through the same, illustrating the manner of packing and charging the furnace. the walls and floors l l', of the furnace are made of fire bricks, and do not necessarily have to be very thick or strong, the heat to which they are subjected not being excessive. the carbon plates are smaller than the cross section of the box, as shown, and the spaces between them and the end walls are packed with fine charcoal. the furnace is covered with a removable slab of fireclay, n, which is provided with one or more vents, _n_, for the escaping gases. the space between the carbon plates constitutes the working part of the furnace. this is lined on the bottom and sides with a packing of fine charcoal, o, or such other material as is both a poor conductor of heat and electricity--as, for example, in some cases, silica or pulverized corundum or well-burned lime--and the charge, p, of ore and broken, granular, or pulverized carbon occupies the center of the box, extending between the carbon plates. a layer of granular charcoal, o', also covers the charge on top. the protection afforded by the charcoal jacket, as regards the heat, is so complete, that with the covering-slab removed, the hand can be held within a few inches of the exposed charcoal jacket; but with the top covering of charcoal also removed and the core exposed, the hand cannot be held within several feet. the charcoal packing behind the carbon plates is required to confine the heat and to protect them from combustion. with this furnace, aluminum can be reduced directly from its ores; and chemical compounds from corundum, cryolite, clay, etc., and silicon, boron, calcium, manganese, magnesium, and other metals are in like manner obtained from their ores and compounds. the reduction of ores according to this process can be practiced, if circumstances require it, without any built furnace. at present, the cowles company is engaged mostly in the producing of aluminum bronze and aluminum silver and silicon bronze. the plant, were it run to its full capacity, is capable of turning out eighty pounds of aluminum bronze, containing per cent. of aluminum daily; or, were it to run upon silicon bronze, could turn out one hundred and twenty pounds of that per day, or, we believe, more aluminum bronze daily than can be produced by all other plants in the world combined. this production, however, is but that of the experimental laboratory, and arrangements are making to turn out a ton of bronze daily, and the works have an ultimate capacity of from eight to ten thousand horse power. the energy consumed by the reduction of the ore is almost entirely electrical, only enough carbon being used to unite with the oxygen of the ore to carry it out of the furnace in the form of the carbon monoxide, the aluminum remaining behind. consequently, the plant necessary to produce aluminum on a large scale involves a large number of the most powerful dynamos. these are to be driven by water-power or natural gas and marine engines of great capacity. the retail price of standard per cent. aluminum bronze is $ per pound avoirdupois, which means less than $ per pound for aluminum, the lowest price at which it has ever been sold, yet the cowles company has laid a proposition before the government to furnish this same bronze in large quantities at very much lower prices than this. the hercules alloy, castings of which will stand over , pounds to the square inch tensile strain, sells at c. a pound, and is also offered the government or other large consumers at a heavy discount. the alloys are guaranteed to contain exactly what is advertised; they are standardized into per cent., . per cent., per cent. and . per cent. aluminum bronze before shipment. the current available at the cowles company's works was, until recently, amperes, driven by an electromotive force of volts and supplied by two edison dynamos; but the company has now added a large brush machine that has a current of amperes and volts electromotive force. we shall, on another occasion, give some particulars of experiments in the reduction of refractory ores by the process.--_eng. and mining jour._ * * * * * optical telegraphy.[ ] [footnote : continued from page .] cryptography.--preservation of telegrams. optical telegraphy, by reason of its very principle, presents both the advantage and inconvenience of leaving no automatic trace of the correspondence that it transmits. the advantage is very evident in cases in which an optical station falls into the hands of the enemy; on the other hand, the inconvenience is shown in cases where a badly transmitted or badly collated telegram allows an ambiguity to stand subject to dispute. moreover, in case of warfare between civilized nations that have all the resources of science at their disposal, there may be reason to fear lest one of the enemy's optical stations substitute itself for the corresponding station, and take advantage of the situation to throw confusion into the orders transmitted. the remedy for this appears to reside in the use of cryptography and in the exchange, at various intervals, of certain words that have been agreed upon beforehand, and that the enemy is ignorant of. as for the automatic preservation of telegrams, the problem has not been satisfactorily solved. it has been proposed to connect the key of the manipulator of the optical apparatus with the manipulator of an ordinary morse apparatus, thus permitting the telegram to be preserved upon a band of paper. it is unnecessary to say that the space occupied by a dispatch thus transmitted would be considerable; but this is not what has stopped innovators. the principal objection resides in the increase in muscular work imposed by this arrangement upon the telegrapher. obliged to keep his eye fixed intently at the receiving telescope, while at the same time maneuvering the manipulator and spelling aloud the words that he is receiving, the operator should have a very sensitive manipulator at his disposal, and not be submitted to mental or physical overtaxation. so the apparatus that have been devised have not met with much success. two french officers, working independently, have hit upon the same idea of receiving the indications transmitted by the vibration of the luminous fascicle directly upon their travel. the method consists in the use of that peculiar property of selenium of becoming a good conductor under the action of a luminous ray, while in darkness it totally prevents the passage of the electric current. such modification of the physical properties of selenium, moreover, occurs without the perceptible development of any mechanical work. if, then, in the line of travel of the luminous fascicle emitted by the optical apparatus, or in a portion of such fascicle, we interpose a fragment of selenium connected with the two poles of a local pile, it is easy to see that the current from the latter will be opened or closed according as the luminous ray from the apparatus will or will not strike the selenium, and that the length of time during which the current passes will depend upon the length of the luminous attacks. a morse apparatus interposed in this annexed circuit will therefore give an automatic inscription of the correspondence exchanged. such is the principle. but, practically, very great difficulties present themselves, these being connected with the rapid weakening of the electric properties of the selenium, and with the necessity of having recourse to infinitely small mechanical actions only. the problem is nevertheless before us, and it is to be hoped that the perseverance of the scientists who are at work upon it will some day succeed in solving it. finally, we may call attention to the attempts made to receive the luminous impression upon a band prepared with gelatino-bromide of silver. in practice this band would unwind uniformly at the focus of the receiving telescope, which would be placed in a box, forming a camera obscura. the velocity of this band prepared for photographing the signals would be regulated by clockwork. the experiments that have been made have not given results that are absolutely satisfactory, by reason of the length of the signals received and the mechanical complication of the device. optical telegraphy by means of projectors. [illustration: fig. .] the projectors employed for lighting to a distance the surroundings of a stronghold or of a ship have likewise been applied in optical telegraphy. for this purpose messrs. sautter, lemonnier & co. have added to their usual projecting apparatus some peculiar arrangements that permit of occultations of the luminous focus at proper intervals. figs. and show the arrangement of the apparatus, the principle of which is as follows: when the axis of the projector points toward the clouds, and in the direction occupied by a corresponding station, the occultations of the luminous source placed in the focus of the apparatus produce upon the clouds, which act as a screen, an alternate series of flashes and extinctions. it is therefore possible with this arrangement, and by the use of the morse alphabet, to establish an optical communication at a distance. the use of this projector (the principal inconvenience of which is that it requires a clouded sky) even permits two observers who are hidden from each other by the nature of the ground to easily communicate at a distance of or miles. use of the projector in optical telegraphy. [illustration: figs. and .--front view and longitudinal section of the mangin projector. (scale / ). a. elliptical mirror. b. arm of the same. c. nut for fixing the mirror. d. support of the mirror. e. occultator. f. support for same. g. lever for maneuvering the occultator. i. support of the occultator rod. j. screw for fixing the mirror support. k. screw for fixing the support of the occultator rod. l. screw for fixing the occultator support.] the apparatus shown in figs. and permits of signaling in three ways: . _upon the clouds._--in this case the mirror, a, is removed, and the projector inclined above the horizon in such a way as to illuminate the clouds to as great a distance as possible. a maneuver of the occultator, e, between the lamp and the mirror arrests the luminous rays of the source, or allows them to pass, and thus produces upon the clouds the dots and dashes of the conventional alphabet. . _isolated communication by luminous fascicles._--when it is desired to correspond to a short distance of or miles, and establish a communication between two isolated posts, the mirror, a, is put in place upon its support, b. the luminous fascicle emanating from the source reflected by the mirror is thrown vertically. by revolving the mirror ° around its horizontal axis the fascicle becomes horizontal, and may thus be thrown in a given direction at unequal intervals and during irregular times, and furnish conventional signs. . _night communication upon the entire horizon._--when we wish to correspond at a short distance, say two miles, and make signals visible from the entire horizon, the mirror, a, is put in place, so that it shall reflect the luminous fascicle vertically. the fascicle, at a distance of about fifty feet, meets a white balloon which it renders visible from every point in the horizon. the maneuver of the occultator brings the balloon out of darkness or plunges it thereinto again, and thus produces the signs necessary for aerial communication. [illustration: fig. .] these ingenious arrangements, which depend upon the state of the atmosphere, do not appear to have been imitated outside of the navy. capt. gaumet's optical telegraph. the system of optical communication proposed by capt. gaumet, and which he names the _telelogue_, is based upon the visibility of colored or luminous objects, and upon the possibility of piercing the opaque curtain formed by the atmosphere between the observer's eye and a signal, by utilizing the difference in brightness that exists between such objects and the atmosphere. it is a question, then, of giving such difference in intensity its maximum of brightness. to do this, capt. gaumet proposes to employ silvered signals upon a black background. he uses the simple letters of the alphabet, but changes their value. his apparatus has the form of a large album glued at the back to a sloping desk. each silvered letter, glued to a piece of black cloth, is seen in relief upon the open register. a sort of index along the side, as in commercial blank-books, permits of quickly finding any letter at will. such is the manipulator of the apparatus. the receiver consists of a spy-glass affixed to the board that carries the register. for a range of two and a half miles, the complete apparatus, with a × inch manipulator and telescope, weighs but four and a half pounds. for double this range, with a × inch manipulator and telescope, the total weight is thirteen pounds. the larger apparatus, according to the inventor, have a range of seven miles. for night work the manipulator is lighted either by one lamp, or by two lamps with reflector, placed laterally against it. this apparatus, although well known, and having been publicly experimented with, has not, to our knowledge, been applied practically. from a military standpoint, its short range will evidently not permit it to compete with optical telegraphic apparatus, properly so called. perhaps it might rather be of service for private communications between localities not very far apart, since it costs but little and is easily operated. optical signaling between bodies of troops. optical communications by signals, during day and night, with experienced men, may, in the absence of telephones, telegraphs, and messengers, render important service when the distance involved is greater than two thousand feet. this mode of correspondence is based upon the use of the morse alphabet. the signals are divided into night and day ones. the day signals are made with small flags. when these are wanting, sheets of white cardboard may be used. the night signals are made with a lantern provided with a support, which may be fixed to a wall or upon a bayonet. in day signaling, the dashes of the morse alphabet are formed by means of two flags (fig. ) held simultaneously at arm's length by the signaler. the dots are formed with a single flag held in the right hand (fig. ). in this way it is possible, by extremely simple combinations, to establish a correspondence, and produce any conventional signal. by means of relay stations, the signals may be transmitted from one to another to a great distance. in signaling with the lantern, long and short interruptions of the luminous source are produced by means of a screen. optical telegraphy by luminous balloons. various interesting experiments have been made with a view to utilizing luminous captive balloons for optical communications. as we have already seen, this maybe effected by using opaque balloons, and throwing upon them at unequal intervals a luminous fascicle by means of a projector. as for using a luminous source placed in the car of a balloon, that cannot be thought of in the present state of aeronautic science; the continual rotation of the balloon around its axis would render the projection and reception of the signals in a given direction impossible. optical telegraphy in the marine. for communicating optically from ship to ship during the day, the marine uses flags of different forms and colors, and flames. between ships and the land there are used what are called semaphore signals, which are made by means of a mast provided with three arms and a disk placed at the upper part. the combinations of signs thus obtained, which are analogous in principle to those of the chappe telegraph, permit of satisfactorily communicating to a distance. on board ship, hand signals are used like those employed by the army for communicating between bodies of troops. for night communications the marine employs lights corresponding to the day flags, as well as rockets, and luminous rays projected by means of reflectors and intercepted by screens. in conclusion, it may be said that optical telegraphy, which has only within a few years emerged from the domain of theory to enter that of practice, has taken a remarkable stride in the military art and in science. it is due to its processes that col. perrier has in recent years been enabled to carry out certain geodesic work that would have formerly been regarded as impracticable, notably the prolongation of the arc of the meridian between france and spain. very recently, an optical communication established between mauritius and reunion islands, to a distance of miles, with inch apparatus, proved that, in certain cases, the costly laying of a submarine cable may be replaced by the direct emission of a luminous ray. * * * * * a new style of submarine telegraph. mr. f. von faund-szyll has devised an original system of submarine telegraph, which is based upon the well known property that selenium exhibits of modifying its resistance under the influence of luminous rays, and which he styles the _selen-differenzialrecorder_. contrary to what is found in the other systems hitherto employed, the faund-szyll system utilizes the cable current merely for starting the receiving apparatus, which are operated by means of strong local batteries. the result is that the mechanical work that devolves upon the line current, which is, as well known, very weak, is exceedingly reduced. the system consists of two essential parts: ( ) the receiver, properly so called. ( ) the relay as well as the registering apparatus or _differenzialrecorder_. the receiver consists of a closed box, k, in the interior of which there is a very intense source of light whose rays escape by passing through apertures, _a a'_, in the front part (fig. ). as a source of light, there may be conveniently employed an incandescent lamp, _g_, capable of giving an intense light, and arranged (as shown in fig. ) behind the side that contains the slits, _a a'_. the starting apparatus consists of a small galvanometric helix, _r_, analogous to thomson's siphon recorder, which is suspended from a cocoon fiber and capable of moving in an extremely powerful magnetic field, n s. this helix carries, as may be seen in figs. , and , a prolongation, _v_, at its lower end whose form is that of a prism, and which is arranged in front of the partition of the box, k, in such a way that it exactly covers the two slits, a and _a_ when the bobbin is at rest, and in this case prevents the luminous rays of the lamp, _g_, from escaping from the box. but, as soon as the current sent through the cable reaches the spirals of the bobbin, through the conductors, _y y'_, the sum of the elementary electrodynamic actions that arise causes the helix to revolve to the right or left, according to the polarity of the current, while at the same time the helix slightly approaches one or the other of the poles of the magnet. the prolongation, _v_, of the helix, being firmly united with the latter, follows it in its motion, and has the effect of permitting the luminous rays to escape through one or the other of the slits, _a a'_, so that the freeing of the luminous fascicle, if such an expression is allowable, is effected. [illustration: fig. .] in order to prevent oscillations, which could not fail to occur after each emission of a current (so that the helix, instead of returning to a position of equilibrium and stopping there, would go beyond it and alternately uncover the slits, _a a'_), the apparatus is provided with a liquid deadener. to this end, the prolongation, _v_, carries a piece, _o_, which dips into a cup containing a mixture of glycerine and water. we shall now describe the _differenzialrecorder_. opposite the two slits, _a_ and _a'_, there are two powerful converging lenses, _l_ and _l'_, whose foci coincide with two sorts of selenium plate rheostat, _z_ and _z'_. the result of this arrangement is that as soon as one of the slits, as a consequence of the displacement of the helix, _r_, allows a luminous fascicle to escape, this latter falls upon the corresponding lens, which concentrates it and sends it to the selenium plates just mentioned. under the influence of the luminous rays, the resistance that the selenium offers to the passage of an electric current instantly changes. at m and m' are placed two horseshoe magnets whose poles are provided with pieces of soft iron that serve as cores to exceedingly fine wire bobbins, _d_. these polarized pieces are arranged in the shape of a st. andrew's cross, and in such a way that the poles of the same name occupy the two extremities of the same arm of the cross, an arrangement very clearly shown in fig. . [illustration: fig. .] between the poles of the magnets, m and m', there is a permanent magnet, a, movable around a vertical axis, _i_. four spiral springs, _f_, whose tension may be regulated, permit of centering this latter piece in such a way that when the current is traversing the spirals of the polar bobbins it is equally distant from the four poles, _n_, _s_, _s'_, and _n'_. under such circumstances it is evident that a difference in the power of attraction of these four poles, however feeble it be, will result in moving the magnet, a, in one direction or the other around its axis. the energy and extent of such motion may, moreover, be magnified by properly acting upon the four regulating springs. the bobbins of the magnet, m, are mounted in series with the selenium plates, _z_, the local battery, b, and a resistance box, w. those of the magnet, m', are in series with _z'_, b', and w'. the local batteries, b and b', are composed of quite a large number of elements. the current from the battery, b, traverses the selenium plates and the bobbins of the magnet, m, and returns to b through the rheostat, w; and the same occurs with the current from b'. the two currents, then, are absolutely independent of one another. from this description it is very easy to see how the system works. let us suppose, in fact, that the current which is traversing the spirals of the helix, _r_, has a direction such that the helix in its movement approaches the pole, s; then the prolongation, _v_, will uncover the slit, _a_, which, along with _a'_, had up to this moment been closed, and a luminous fascicle escaping through _a_ will strike the lens, _l'_, and from thence converge upon the selenium plates, _z'_. this is all the duty that the line current has to perform. the luminous rays, in falling upon the selenium plates, _z'_, modify the resistance that these offered to the passage of the current produced by the battery, b'. as this resistance diminishes, the intensity of the current in the circuit supplied by the battery, b', increases, the attractive action of the polar pieces of the magnet, m', diminishes, the equilibrium is destroyed, and the piece, a, revolves around the axis, _i_. if the polarity of the line current were different, the same succession of phenomena would occur, save that the direction of a's rotation would be contrary. as for the rheostats, w w', their object is to correct variations in the selenium's resistance and to balance the resistances of the two corresponding circuits. the magnet, a, will be combined with a registering apparatus so as to directly or indirectly actuate the printing lever. the entire first part of this apparatus, which is very sensitive, may be easily protected from all external influence by placing it in a box, and, if need be, in a room distant from the one in which the employes work. [illustration: figs. and .] the _differenzialrecorder_ alone has to be in the work room. as may be seen, the system is not wanting in originality. experience alone will permit of pronouncing upon the question as to whether it is as practical as ingenious.--_la lumiere electrique._ * * * * * a new circuit cutter. messrs. thomson & bottomley have recently invented a peculiar circuit cutter based upon the use of a metal whose melting point is exceedingly low. recourse is had to this process for breaking the current within as short a time as possible. in this new device the ends of the conductors are soldered together with the metal in question at one or several points of the circuit. the metal employed is silver or copper of very great conductivity, seeing that the increase of temperature in a conductor, due to a sudden increase of the current, is inversely proportional to the product of the electric resistance by the specific heat of the conductor; that these metals are best adapted for giving constant and definite results; and that the contacts are better than with lead or the other metals of low melting point which are frequently employed in circuit cutters. [illustration: fig. .] fig. represents one form of the new device. here, a is the copper or silver wire, and _b_ is a soldering made with a very fusible metal and securing a continuity of the circuit. each extremity of the wire, _a_, is connected with a heavy ring, _c_, of copper or other good conducting metal. the hook, _d_, with which the upper ring, _c_, is in contact, communicates metallically with one of the extremities of the conductor at the place where the latter is interrupted for the insertion of the circuit cutter. the hook, _e_, with which the lower ring, _c_, is in contact, tends constantly to descend under the action of a spiral spring, _f_, which is connected metallically with the other extremity of the principal conductor. the hooks, _d_ and _e_, are arranged approximately in the same vertical plane, and have a slightly rounded upper and lower surface, designed to prevent the rings, _c_, of the fusible wire, _a_, from escaping from the hooks. in fig. the position of the arm, _e_, when there is no fusible wire in circuit, is shown by dotted lines. when this arm occupies the position shown by entire lines, it exerts a certain traction upon the soldering, _b_, and separates the two halves of the wire, _a_, as soon as the intensity of circulation exceeds its normal value. the mode of putting the wire with fusible soldering into circuit is clearly shown in the engraving. [illustration: fig. .] fig. shows a different mode of mounting the wire. the wire, _q_, is soldered in the center, and is bent into the shape of a u, and kept in place by the pieces, _r_ and _s_. in this way the two ends of it tend constantly to separate from each other. messrs. thomson & bottomley likewise employ weights, simply, for submitting the wire to a constant stress. the apparatus is inclosed in a box provided with a glass cover.--_la lumiere electrique._ * * * * * new micro-telephonic apparatus. despite the simplicity of their parts, and the slight value of the materials employed, the existing micro-telephonic apparatus keep at relatively high prices, and the use of them is often rejected, to the benefit of speaking tubes, when the distance between stations is not too great. we propose to describe a new style of apparatus that are in no wise inferior to those in general use, and the price of which is relatively low. the microphone transmitter may have several forms. the most elementary of these consists of two pieces of carbon, from one to one and a quarter inches in length by one-half inch in width, between which are fixed two _nails_, about two inches in length, whose extremities, filed to a point, enter small conical apertures in the carbons. fig. gives an idea of the arrangement. [illustration: fig. .] fig. represents a model which is a little more complicated, but which gives remarkable results. the largest nail is here two inches in length, and the shortest three-quarter inch. [illustration: fig. .] the receivers may be bell telephones of the simplest form found in the market (fig. ); but for these there may be substituted a bar of soft iron, cast iron, or steel, one of the extremities of which is provided with a bobbin upon, which is wound insulated copper wire . inch in diameter. the apparatus is mounted like an ordinary bell telephone. a horseshoe electro may also be used, and the poles be made to act (fig. ). the current sent by the transmitter suffices to produce a magnetic field in which the variations in intensity produced by the microphone succeed perfectly in reproducing speech and music. with four leclanche elements, the sounds are perceived very clearly. the elements used may be bichromate of potash ones, those of lelande and chaperon, etc. [illustration: fig. .--receiver.] [illustration: fig. .] to this apparatus there may be added a second bobbin of coarser wire into which is passed a current from a local pile. this produces a much intenser magnetic field, and, consequently, louder sounds. this modification, however, is really useful only for long distances. any arrangement imaginable may be given the transmitter and receiver; but, aside from the fact that the ones just indicated are the simplest, they give results that are at least equal, if not superior, to all others. we shall insist here only upon the arrangement of the microphone, which is new (at least in practice), and upon the uselessness of having well magnetized steel bars and wires of extreme fineness in the receiver. [illustration: fig. .] we have stated that the nail microphones are the simplest. the nails may be replaced by copper or any other metal, or they may be well nickelized; but common nails answer very well, and do not oxidize much. an apparatus of this kind (fig. ) that has been for more than a year in a laboratory filled with acid vapors is yet working very well. these apparatus possess the further advantage of being very strong, and of undergoing violent shocks without breaking or even getting out of order. they may be used either with or without induction coils. we have not yet measured their range, but can cite the following fact: one of these apparatus, quite crudely mounted, was put into a circuit with a resistance of ohms. with a single already exhausted bichromate element, giving scarcely volts, musical sounds and speech reached the receiver without being notably weakened. such resistance represents a length of eighteen miles of ordinary telegraph wire. after this, ohms were overcome with . volts. this result was obtained by direct transmission, and without an induction coil, and it is probable that it might be much exceeded without sensibly increasing the electromotive force of the current.--_le genie civil._ * * * * * messrs. kapp and crompton's measuring instruments. we give herewith, from the _elektrotechnische zeitschrift_, a few interesting details in regard to the measuring apparatus of messrs. kapp and crompton. it is evident that when we use permanent magnets or springs as directing forces in measuring instruments, we cannot count upon an absolute constancy in the indications, as the magnetism of the magnetized pieces, or the tension of the springs, modifies in time. the apparatus require to be regulated from time to time, and hence the idea of substituting electro-magnets for permanent ones. [illustration: fig. .] if we suppose (fig. ) a magnetized needle, _n s_, placed between the extremities of a soft iron core, n s, and if we group the circuit in such a way that the current, after traversing the coil, _e e_, of the electro, traverses a circle, _d d_, situated in a plane at right angles with the plane of the needle's oscillation, it is evident that we shall have obtained an apparatus that satisfies the aforesaid conditions. it seems at first sight that in such an instrument the directing force should be constant from the moment the electro was saturated, and it would be possible, were sufficiently thin cores used, to obtain a constancy in the directing magnetic field for relatively feeble intensities. in reality, the actions are more complex. the needle, _n s_, is, in fact, induced to return to its position of equilibrium by two forces, the first of which (the attraction of the poles, n s) rapidly increases with the intensity so as to become quickly and perceptibly constant, while the second (the sum of the elementary electrodynamic actions that are exerted between the spirals, _e e_, and the needle, _n s_) increases proportionally to the intensity of the current. if we represent these two sections graphically by referring the magnetic moments as ordinates and the current intensities as abscissas to two co-ordinate axes (fig. ), we shall obtain for the first force the curve, o a b, which, starting from a, becomes sensibly parallel with the axis of x, and for the second the right line, o d. the resultant action is represented by the curve, o e e'_f. it will be seen that this action, far from being constant, increases quite rapidly with the intensity of the current, so that the deflections would become feebler and feebler for strong intensities, of current; and this, as well known, would render the apparatus very defective from a practical point of view. [illustration: fig. .] but the action of the spirals can be annulled without sensibly diminishing the magnetism of the core by arranging a second system of spirals identical with the first, but placed in a plane at right angles therewith, or, more simply still, by having a single system of spirals comprising the coil of the electro-magnet, but distributed in a plane that is oblique with respect to the needle's position of rest. it then becomes possible, by properly modifying such angle of inclination, to obtain a total directing action that shall continue to increase with the intensity, and which, graphically represented, shall give the curve, o g g'_h, for example (fig. ). [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] this arrangement, which is adopted in mr. kapp's instruments, gives very good results, as may be easily seen by reference to figs. and , in which the current intensities or differences of potential are referred as ordinates and the degrees of deflection of the needle as abscissas. the unbroken lines represent the curves obtained with the apparatus just described, while the dotted ones give the curve of deflection of an ordinary tangent galvanometer. these curves show that for strong intensities of current mr. kapp's instrument is more advantageous than the tangent galvanometer. mr. crompton has constructed an amperemeter upon the same principle, which is shown in fig. .--_la lumiere electrique._ * * * * * the chemical action of light. professor a. vogel, in a communication to the "sitzungsberichte der munchener akademie," brings into prominence the fact that the hemlock plant, which yields coniine in bavaria, contains none in scotland. hence he concludes that solar light plays a part in the generation of the alkaloids in plants. this view is corroborated by the circumstance that the tropical cinchonas, if cultivated in our feebly lighted hothouses, yield scarcely any alkaloids. prof. vogel has proved this experimentally. he has examined the barks of cinchona plants obtained from different conservatories, but has not found in any of them the characteristic reaction of quinine. of course it is still possible that quinine might be discovered in other conservatory-grown cinchonas, especially as the specimens operated upon were not fully developed. but as the reaction employed indicates very small quantities of quinine, it may be safely assumed that the barks examined contained not a trace of this alkaloid, and it can scarcely be doubted that the deficiency of sunlight in our hothouses is one of the causes of the deficiency of quinine. it will at once strike the reader as desirable that specimens of cinchonas should be cultivated in hothouses under the influence of the electric light, in addition to that of the sun. if sunlight can be regarded as a factor in the formation of alkaloids in the living plant, it has, on the other hand, a decidedly injurious action upon the quinine in the bark stripped from the tree. on drying such bark in full sunlight the quinine is decomposed, and there are formed dark-colored, amorphous, resin-like masses. in the manufacture of quinine the bark is consequently dried in darkness. this peculiar behavior of quinine on exposure to sunlight finds its parallel in the behavior of chlorophyl with the direct rays of the sun. it is well known that the origin of chlorophyl in the plant is entirely connected with light, so that etiolated leaves growing in the dark form no chlorophyl. but as soon as chlorophyl is removed from the sphere of vegetable life, a brief exposure to the direct rays of the sun destroys its green color completely. prof. a. vogel conjectures that the formation of tannin in the living plant is to some extent influenced by light. this supposition is supported by the fact that the proportion of tannin in beech or larch bark increases from below upward--that is, from the less illuminated to the more illuminated parts, and this in the proportions of : and : . sunny mountain slopes of a medium height yield, according to wide experience, on an average the pine-barks richest in tannin. in woods in level districts the proportion of tannin is greatest in localities exposed to the light, while darkness seems to have an unfavorable effect. here, also, we must refer to the observation that leaves exceptionally exposed to the light are relatively rich in tannin. we may here add that in the very frequent cases where a leaf is shadowed by another in very close proximity, or where a portion of a leaf has been folded over by some insect, the portion thus shaded retains a pale green color, while adjacent leaves, or other portions of the same leaf, assume their yellow, red, or brown autumnal tints. if, as seems highly probable, these tints are due to transformation products of tannin, we may not unnaturally conclude that they will be absent where tannin has not been generated.--_jour. of science._ * * * * * eutexia.[ ] [footnote : read before the birmingham philosophical society, january , .] by thomas turner, assoc. r.s.m., f.c.s., demonstrator of chemistry, mason college. there are a number of interesting facts, some of which are known to most persons, and many of them have been long recognized, of which, however, it must be owned that the explanation is somewhat obscure, and the connections existing between them have been but recently pointed out. as an example of this, it is well known that salt water freezes at a lower temperature than fresh water, and hence sea-water may be quite liquid while rivers and ponds are covered with ice. again, it is noticed that mixtures of salts often have a fusing-point lower than that of either of the constituent salts, and of this fact we often take advantage in fluxing operations. further, it is well known that certain alloys can be prepared, the melting-points of which are lower than the melting-point of either of the constituent metals alone. thus, while potassium melts at . ° c., and sodium at about °, an alloy of these metals is fluid at ordinary temperatures, and fusible metal melts below the temperature of boiling water, or more than ° lower than the melting-point of tin, the most fusible of the three metals which enter into the composition of this alloy. but though these and many similar facts have been long known, it is but recently, owing largely to the labors of dr. guthrie, that fresh truths have been brought to light, and a connection shown to exist throughout the whole which was previously unseen, though we have still to acknowledge that at present there is much at the root of the matter which is but imperfectly understood. still dr. guthrie proves a relationship to exist between the several facts we have previously mentioned, and also between a number of other phenomena which at first sight appear to be equally isolated and unexpected, and we are asked to regard them all as examples of what he has called "eutexia." we may define a eutectic substance as a body composed of two or more constituents, which constituents are in such proportion to one another as to give to the resultant compound body a minimum temperature of liquefaction--that is, a lower temperature of liquefaction than that given by any other proportion.[ ] it will be seen at once by this definition that the temperature of liquefaction of a eutectic substance is lower than the temperature of liquefaction of either or any of the constituents of the mixture. and, further, it is plain that those substances only can be eutectic which we can obtain both as liquid and solid, and hence the property of eutexia is closely connected with solution. [footnote : guthrie, _phil. mag._ [ ], xvii., p. .] following in the natural divisions adopted by dr. guthrie, we may consider eutexia in three aspects: i. cryohydrates. if a _dilute_ aqueous saline solution be taken at ordinary temperatures, and then slowly cooled to some point below zero on the centigrade scale, the following series of changes will in general be observed: on reaching a point below zero, the position of which is dependent upon the nature of the salt and the amount of dilution, it will be found that ice is formed; this will float upon the surface of the solution, and may be readily removed. if the ice so removed be afterward pressed, or carefully drained, it will be found to consist of nearly pure water, the liquid draining away being a strong saline solution which had become mechanically entangled among the crystals of ice during solidification. if we further cool the brine which remains, we notice a tolerably uniform fall of temperature with accompanying formation of ice. but at length a point is reached at which the temperature ceases to fall until the whole of the remaining mother-liquor has solidified, with the production of a compound called a cryohydrate,[ ] which possesses physical properties different from those of either the ice or the salt from which it is formed. [footnote : guthrie, _phil. mag._, th series, xlix., pp. , , ; th series, i., pp. , , , vi., p. .] if, on the other hand, we commence with a _saturated_ saline solution, in general it is noticed on cooling the liquid a separation of salt ensues, which salt sinks to the bottom of the mass, and may be removed. the salt so separating may be either anhydrous or a "hydrate" of greater concentration than the mother-liquor. so long as this separation proceeds the temperature falls, but at length a point is reached at which the thermometer remains stationary until the whole is solidified, with the production of a cryohydrate. this temperature of solidification is the same whether we start with a dilute or a saturated solution, and the composition of the cryohydrate is found to be constant. the temperature of production of the cryohydrate is identical with the lowest temperature which can be produced on employing a mixture of ice and the salt as a freezing mixture or cryogen. it will be readily seen that in the formation of a cryohydrate we have an example of eutexia, since the constituents are present in such proportion as to give to the resultant compound body a minimum temperature of liquefaction. ii. eutectic salt alloys.[ ] [footnote : f. guthrie, _phil. mag._ [ ], xvii., p. ; f.b. guthrie, _journ. chem. soc_,. , p. .] although it has been long known that on mixing certain salts the resulting substance possessed a lower melting-point than either of the constituent salts alone, still but few determinations of the melting-points of mixtures of salts have been made, and even these are often of small value, on account of the very considerable range of temperature observed during solidification. this is due largely to the fact that eutectic mixtures were not known, as equivalent proportions of various salts have been employed, while eutectic mixtures are seldom found to possess any simple arithmetical molecular relationship between their constituents. eutectic salt alloys closely resemble cryohydrates in behavior. if for simplicity we confine our attention to a fused mixture of two salts in any proportion other than eutectic, it is found that, on cooling, the thermometer falls steadily, until at length that salt which is in excess of the proportion required for a eutectic mixture begins to separate out. if this is removed, the thermometer falls until a fixed point is reached at which the temperature remains stationary until the whole of the mixture solidifies. on remelting, the temperature of solidification is found to be quite fixed, and the mixture is evidently eutectic. it is of interest to notice that from our knowledge of the cryohydrates it becomes possible to predict the existence, composition, and temperature of solidification of a eutectic alloy, if we are previously furnished with the melting-points of mixtures of the substances in question. or, in other cases, we may predict from the curve of melting-points that no eutectic alloy is possible. as an example, we may take the determinations of the melting-points of mixtures of potassium and sodium nitrate by m. maumené.[ ] these are graphically represented in fig. , the curve being derived from the mean of the temperatures given in the memoir. from this diagram we should be led to expect a eutectic mixture, since the curve dips below a horizontal line passing through the melting-point of the more fusible of its constituents. from our curve we should expect a eutectic mixture with about per cent. kno_{ }, and with a temperature of solidification below °. dr. guthrie gives . per cent. at °. this agreement is as good as might be expected when one remembers that the melting-points, not being of eutectic mixtures, are difficult to determine, and a considerable range is given; that analyses of mixtures of potassium and sodium salts are apt to vary; and that the two observers differ by ± ° in the temperatures given for the melting-points of the original salts. [footnote : _comptes rendus_, , , p. .] [illustration: fig. .] dr. tilden has drawn my attention to an interesting example of the lowering of melting-point by the mixture of salts. the melting-point of monohydrochloride of turpentine oil is °, while that of the dihydrochloride is °; but on simply stirring together these compounds in a mortar at common temperatures, they immediately liquefy. two molecules of the monohydrochloride and one molecule of the dihydrochloride form a mixture which melts at about °. iii. eutectic metallic alloys. although many fusible alloys have been long known, i believe no true eutectic metallic alloy had been studied until dr. guthrie[ ] worked at the subject, employing the same methods as with his cryohydrates. it is found if two metals are fused together and the mixture allowed to cool, that the temperature falls until a point is reached at which that metal which is present in a proportion greater than is required to form the eutectic alloy begins to separate. if this solid be removed as it forms, the temperature gradually falls until a fixed point is reached, at which the eutectic alloy solidifies. here the thermometer remains stationary until the whole has become solid, and, on remelting, this temperature is found to be quite fixed. in addition to the di-eutectic alloys, we have also tri- and tetra-eutectic alloys, and as an example of the latter we may take the bismuth-tin-lead-cadmium eutectic alloy, melting at °. [footnote : _phil. mag._, th series, xvii., p. .] we have already seen with salt eutectics that, given the curve of melting-points of a mixture in various proportions, we may predict the existence, composition, and melting-point of the eutectic alloy. as a matter of course, the same thing holds good for metallic eutectics. an interesting example of this is furnished by the tin-lead alloys, the melting-points of which have been determined by pillichody.[ ] from these determinations we obtain the curve given in fig. , and from this curve, since it dips below a horizontal line passing through the melting-point of the more fusible constituent, we are at once able to predict a eutectic alloy. we should further expect this to have a constitution between pbsn_{ } and pbsn_{ } and a melting-point somewhat below °. on melting together tin and lead, and allowing the alloy to cool, we find our expectation justified; for by pouring off the fluid portion which remains after solidification has commenced, and repeating this several times with the portion so removed, we at length obtain an alloy which solidifies at the constant temperature of °, when the melting-point of tin is taken as °. on analysis . grm. of this alloy gave . grm. sno_{ }, which corresponds to sn . per cent., or pbsn_{ . }. this, therefore, is the composition of the eutectic alloy, and it finds its place naturally on the curve given in fig. . [footnote : _dingler's polyt. journ._, , p. ; _jahresberichte_, , p. .] [illustration: fig. .] it will be seen that the subject of eutexia embraces many points of practical importance and of theoretical interest. thus it has been shown by dr. guthrie that the desilverizing of lead in pattinson's process is but a case of eutexia, the separation of lead on cooling a bath of argentiferous lead poor in silver being analogous to the separation of ice from a salt solution. dr. guthrie has also shown that eutexia may reasonably be supposed to have played an important part in the production and separation of many rock-forming minerals. it is with considerable diffidence that i suggest the following as an explanation of the multitude of facts to which previous reference has been made. in a mixture of two substances, a and b, we have the following forces active, tending to produce solidification: . the cohesion between the particles of a. . the cohesion between the particles of b. . the cohesion between the particles of a and the particles of b. with regard to this last factor, it will be seen that there are three cases possible: . the cohesion of the mixture a b may be greater than the cohesion of a + the cohesion of b. . the cohesion of a b may be equal to the cohesion of a + the cohesion of b. . the cohesion of a b may be less than the cohesion of a + the cohesion of b. now, since cohesion tends to produce solidification, we should in the first case expect to find the melting-point of the mixture _higher_ than the mean of the melting-points of its constituents, or the curve of melting-points would be of the form given in _a_, fig. . here no eutectic mixture is possible. [illustration: fig. .] in the second case, where cohesion a b = cohesion a + b, we should obtain melting-points for the mixture which would agree with the mean of the melting-points of the constituents, the curve of melting-points would be a straight line, and again no eutectic mixture would be possible. in the third case, however, where cohesion a b is less than cohesion a + b, we should find the melting-points of the mixture lower than the mean of the melting-points of its constituents, and the curve of melting-points would be of the form given in _e_, fig. . here, in those cases where the difference of cohesion on mixture is considerable, the curve of melting-points may dip below the line _e f_. this is the _only case_ in which a eutectic mixture is possible, and it is, of course, found at the lowest point of the curve. if it be true, as above suggested, that the force of cohesion is at its minimum in the eutectic alloy, we should expect to find, in preparing a eutectic substance, either that actual expansion took place, or that the molecular volume would gradually increase in passing along our curve of melting-points, from either end, for each molecule added, and that it would obtain its greatest value at the point corresponding to the eutectic alloy. of this i have no direct evidence as yet, but it is a point of considerable interest, and i may possibly return to it at some future time.--_chemical news._ * * * * * chinoline. dr. conrad berens, of the university of pennsylvania, reaches the following: . chinoline tartrate is a powerful agent, producing death by asphyxia. . the drug increases the force and frequency of the respirations by stimulating the vagus roots in the lung. . it paralyzes respiration finally by a secondary depressant action upon the respiratory center. . it does not cause convulsions. . it lessens and finally abolishes reflex action by a direct action upon the cord, and by a slight action upon the muscles and nerves. . it diminishes or abolishes muscular contractility respectively when applied through the circulation or directly. . it coagulates myosin and albumen. . it causes insalivation by paralysis of the secretory fibers of the chorda tympani; increases the flow of bile; has no action upon the spleen. . it lowers blood-pressure by paralyzing the vaso-motor centers and by a direct depressant action upon the heart muscle. . it diminishes the pulse rate by direct action upon the heart. . it lowers the temperature by increasing the loss of heat. . it is a powerful antiseptic; and, finally, . its paths of elimination are not known. * * * * * method for rapid estimation of urea. being called upon to make a good many brief and rapid analyses of urine on "clinic days" of our medical department, i devised the following modification of knop's method of estimating urea; and after using it for a year with perfectly satisfactory results, venture to describe and recommend it as especially adapted for physicians' use, by reason of simplicity, cheapness, and accuracy. in perfecting and testing it i was assisted greatly by j. torrey, jr., then working with me. [illustration] the apparatus consists of the glass tube, a, which is about cm. long and ½ cm. in diameter, joined to the tube, b, which is about or cm. in length in its longer arm and or in its shorter, and has a diameter of about mm. near the bend is an outlet tube, _c_, provided with "ball valve" or pinch cock. _d_, _e_, _f_, _g_, are marks upon the tubes. c is a rubber cork with two holes through which the bent tube, d, passes. d is of such size and length as to hold about c.c., and one of its ends may be a trifle longer than the other. the apparatus is used as follows: remove the cork and pour in mercury until it stands at _e_ and _g_, then fill up to the mark, _f_, with sodium or potassium hypobromite (made by shaking up bromine with a strong solution of sodium or potassium hydroxide). next carefully fill the tube in the cork with the urine, being careful especially not to run it over or leave air bubbles in it. this can easily be done by using a small pipette, but if accidentally a little runs over, it should be wiped off the end of the cork with blotting paper. the cork is then to be inserted closely into the tube; the urine tube being so small, the urine will not run out in so doing. the mercury is then drawn out through _c_ till it stands in b at _d_. its level in a will of course not be changed greatly. now, incline the apparatus till the surface of the hypobromite touches the urine in the longer part of the urine tube, and then bring it upright again. the urine will thus be discharged into the hypobromite, which will of course decompose the urea, liberating nitrogen, which will cause the mercury to rise in b. shake until no further change of level is seen, and mark the level of mercury in b with a rubber band, then remove the cork, draw out the liquid with a pipette, dry out the tube above the mercury with scrap of blotting paper, pour back the mercury drawn out, and repeat the process to be sure that no error was made. if now two or three marks have been made upon the tube, b, indicating the height of the mercury when solutions containing known per cents. of urea are used, an accurate opinion can be at once formed as to the condition of the urine as regards urea. as is well known, normal urine contains about . - per cent. of urea, so that graduations representing , . , , and per cent. are usually all that are needed, though of course many more can be easily made. the results obtained with this apparatus have been repeatedly compared with those of more elaborate ones, and no practical difference observed. evidently the same apparatus, differently graduated, might be employed to determine the carbonate present in such a substance as crude soda ash or other similar mixture. in such a case the weighed material would be put upon the mercury with water and the small tube filled with acid. bowdoin college chemical laboratory.--_f.c. robinson, in amer. chem. jour._ * * * * * a catalogue containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . stitched in paper, or $ . bound in stiff covers. combined rates.--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway. new york, n.y. * * * * * patents. in connection with the scientific american, messrs. munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats, trade marks, their costs, and how procured. address munn & co., broadway, new york. branch office, cor. f and th sts., washington, d.c. [illustration] scientific american supplement no. new york, may , scientific american supplement. vol. xix, no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. page i. chemistry.--notes on three new chinese fixed oils.--tea oil.--cabbage oil.--wood oil.--paper read by r. h. davies before the pharmaceutical society of great britain. ii. engineering and mechanics.--a visit to the creusot works.--giving a description of the works and the projects undertaken by the proprietors.--with full page of engravings illustrating the hall of forges and the ton steam hammer. le creusot.--extract of the report of the visit of the american gun foundry board to these works. plan for the elevated railway at paris.-- figures. engineering inventions since .--by sir f. j. bramwell.--bridge construction.--pneumatic foundations.--construction of tunnels.--canals and river improvements.--military engineering appliances.--uses of cement.--preservation of wood. iii. physics, electricity, etc.--electric light apparatus for military purposes.--with engraving. electricity and magnetism.--by prof. f. e. nipher. the hydrodynamic researches of prof. bjerknes.--by c. w. cooke.-- figures. electrotyping.--with a full description of the process. a new seismograph.--with engraving. iv. art and architecture.--the cathedral of the incarnation at garden city. movable market buildings.-- figures and engraving of movable flower market at paris. dinocrates' project.--with three engravings of landscapes showing human profiles. the babylonian palace. v. horticulture.--the stone pine (pinus pinea).--with engraving. vi. hygiene, etc.--the otoscope.--with engraving. state provision for the insane.--by c. m. hughes, m.d. vii. miscellaneous.--the xylophone.-- engravings. the courage of originality. a circular bowling alley.--with engraving. patent office examination of inventions. the universal exposition at antwerp, belgium.--with full page engraving. the art of breeding. * * * * * acknowledgments. we give in this number of our supplement several articles with illustrations, for which we are indebted to _la nature_. they are entitled electric light apparatus for military purposes, the otoscope, a new seismograph, dinocrates' project, the xylophone, plan of an elevated railway for paris. * * * * * a visit to the creusot works. here we are at the great forge (fig. ), that wonderful creation which has not its like in france, that gigantic construction which iron has wholly paid for, and which covers a space of twenty-four acres. we first remark two puddling halls, each of which contains furnaces and steam hammers. it is in these furnaces that the iron is puddled. the ball or bloom thus obtained is afterward taken to the hammer, which crushes it and expels the scoriæ. [illustration: fig. .--the great hall of forges at the creusot works.] the puddler's trade, which is without doubt the most laborious one in metallurgy, will surely soon be lightened through the use of steam. two rotary furnaces actuated by this agent have been in operation for a few years at creusot, and each is yielding tons of iron per day. we have but a court of feet in width to cross in order to reach the rolling mill. at the entrance to this we enjoy one of the most beautiful sights that the immense works can offer. for a length of , feet we perceive on one side a series of rolling machines, and on the other a row of reverberatory furnaces that occasionally give out a dazzling light. in the intervals are fiery blocks that are being taken to the rolling machines, in order to be given the most diverse forms, according to the requirements of commerce. the iron obtained by puddling is not as yet in its definite state, but the rolling mill completes what the puddling hall does in the rough. five hundred and fifty thousand tons of iron, all shaped, are taken from the forge every day. to reach such a result it requires no less than , workmen and a motive power of , horses. but do not be appalled at the cost of the coal, for, thanks to ingenious processes, the heat lost from the furnaces nearly suffices to run the boilers. if we remark that a power of one horse does in one hour the equivalent of a man's labor per day, we conclude that these machines (which run night and day) represent an army of , men that lends its gratuitous aid to the workmen of the forge. this is what is called progress in industry. we have just seen that iron is obtained in small masses. these can be welded upon heating them to , or , degrees. it is impossible to manufacture a large piece exempt from danger from the weldings. cast iron always has defects that are inherent to its nature, and these are all the more dangerous in that they are hidden. steel is exempt from these defects, and, moreover, whatever be the size of the ingot, its homogeneousness is perfect. this is what has given the idea of manufacturing from it enormous marine engines and those gigantic guns that the genius of destruction has long coveted. ah, if the good sense of men does not suffice to put a limit to their increasing progress, bridges, viaducts, and tunnels will take it upon themselves, if need be, to bar their passage. but, in order to forge large ingots, it became necessary before all to increase the power of the steam hammer. the creusot establishment, which endowed metallurgy with this valuable machine, had allowed itself to be eclipsed, not by the number (for it had ), but by the dimensions of the largest one. in , the krupp works constructed one of tons, and their example was followed at perm, st. petersburg, and woolwich. it was then that mr. henry schneider put in execution a bold project that he had studied with his father, that of constructing a ton steam hammer, along with the gigantic accessories necessary (fig. ). it became necessary to erect a building apart for its reception. this structure covers a surface of one and three-quarter roods, and reaches a height of feet in the center. as for the hammer, imagine uprights feet in height, having the shape of the letter a, surmounted with a cylinder ½ feet in length and of a section of ½ square yards. [illustration: fig. .--the creusot one hundred ton steam hammer.] the piston which moves in this cylinder, under a pressure of atmospheres, is capable of lifting a weight of tons. the hammer, which is fixed to this piston by a rod, has therefore an ascensional force of , pounds. it can be raised feet above the anvil, and this gives it a power three and a third times greater than that of the prussian hammer. large guns can therefore be made in france just as well as in germany. this enormous mass is balanced in space at the will of one man, who, by means of a lever, opens and closes two valves without the least effort. this colossal hammer required an anvil worthy of it. this weighs tons, and rests upon granite in the center of feet of masonry. the hammer is surrounded with four furnaces heated by gas, and duty is done for each of these by steam cranes capable of lifting , pounds. these cranes take the glowing block from the furnace, place it upon the anvil, and turn it over on every side at the will of the foreman. under this hammer a cannon is forged as if it were a mere bolt. the piece is merely rough-shaped upon the anvil, and a metallic car running upon a foot track carries it to the adjusting shop. there the cannon is turned, bored, and rifled, and nothing remains but to temper it, that is to say, to plunge it into a bath after it has been heated white hot. for this purpose an enormous ditch has been dug in which there is a cylindrical furnace, and alongside of it there is a well of oil. the car brings the cannon to the edge of the ditch, and a steam crane performs the operation of tempering with as much ease as we would temper a knife blade. in the presence of such engines of attack it was necessary to think of defense. the hammer that forges the cannon also gives us the armor plate to brave it. this time the ingot is flattened under the blows of the hammer, and even takes the rounded form of the stern, if it be so desired. thus is obtained the wall of steel that we wish. will it be possible to keep up the fight long? in order that one may get some idea of this for himself, let us rapidly describe an entirely peaceful contest that took place recently upon the coast of italy. two rival plates, one of them english and the other french, were placed in the presence of the spezia gun, which weighs tons. these plates were strongly braced with planks and old armor plate. three shots were to be fired at each of the plates. in the first shot the ball was of hardened cast iron, and weighed , pounds. the english plate was filled with fissures, while the creusot did not show a single one. the ball penetrated it about seven inches, and was broken into small pieces. in the second shot the projectile was the same, but the charge was greater. the shot may be calculated from the velocity, which was , feet. it was equal to what the great hammer would give were it to fall from a height of a hundred yards. the english plate was completely shivered, while the french exhibited but six very fine fissures radiating from the point struck. the ball entered inches, and was broken as in the first experiment. the third shot fired was with a steel ball, against the french plate, the english being _hors de combat_. the penetration was the same; the ball was not broken, but was flattened at the point like the head of a bolt. we should like to speak of those magnificent workshops in which the immense naval pieces are adjusted, where the shafts of helixes feet in length are turned, and of the boiler works, where one may see generators that have a heating surface exceeding , square feet, for it requires no less than that to supply , h.p., and thus triumph over the force of inertia and those colossal iron-clads. but how describe in a magazine article what the eye cannot take in in a day? despite all our regrets, we have to pass over some things, but our duty will not have been performed if we omit the history of the works. creusot, which to-day is a regularly-built city with a population of , souls, was in but a poor hamlet called charbonniere. the existence there of a coal bed had long been known, and iron ore had been found not far off. but how establish works in a locality deprived of a water course, and distant from the large ways of communication? in the steam engine, which watt had just finally improved, removed the first difficulty, and the second was soon to disappear, thanks to a projected canal. an iron foundry was then established there under the patronage of louis xiv., while the queen had glassworks erected. as long as the war lasted the foundry supported itself through casting cannons and balls, but after the year it became necessary either to transform the works or sell them. it was decided to do the latter. the messrs. chagot, who became purchasers in the sum of $ , , were in turn obliged to sell out in . creusot was then ceded to messrs. manby & wilson, who already had works at charenton. at the end of seven years of efforts this firm made a failure, and, finally, in , after six million dollars had been swallowed up, creusot was bought for $ , , by messrs. adolphe & eugene schneider & co. the period of reverses was at an end, and one of continued success was begun. the new managers had seen that carriage by steam was soon to follow, and open up to metallurgy an entirely new horizon. the works were quickly transformed and enlarged, and in , the first french locomotive was turned out of them. after locomotives came steamboats. it was then that the necessity of forging large pieces gave the idea of a steam hammer. by a coincidence that can only be explained by the needs of the epoch, the english came upon the same discovery almost at the same time, and the creusot patent antedated the english one by only two months. two years afterward, frigates such as the labrador, orenoque, albatros, etc., of h.p., were rivaling english vessels on the ocean. after the death of mr. adolphe schneider, on the d of august, , his brother eugene, left sole manager, displayed an activity that it would be difficult to exceed. he made himself familiar with the resources and productions of foreign countries and of france, and then made up his mind what to do. he desired to make his works the finest in the world, and it has been seen from what precedes that, after twenty years of effort, his aim has been attained. what a rapid progress for so short a time! in , the first locomotive that was not of english origin appeared to us like a true phenomenon; a few years afterward the creusot locomotives were crossing the channel in order to roll proudly over the railways of a rival nation. a general, no matter how skillful, could not conquer with an undisciplined army, so the education of the workmen's children was one of the things that the founder of this great industrial center had constantly in mind. mr. h. schneider has continued the work of his father, and has considerably extended it, at creusot as well as in the annexed establishments. the number of pupils who frequent the schools exceeded , in . the work is not confined to educating the children, but a retreat is afforded the parents, without putting them under any restraint. after twenty-five years' service a workman receives an income of $ if he is a bachelor, and $ if married, but upon one condition, however, and that is that he is a frenchman. for $ . a month he is lodged in a pretty little house surrounded with a garden, and, if he is sick, he is attended gratuitously. these benefits are not addressed to ingrates, as was proved by the profound sorrow that reigned in the little city when the death of the benefactor of creusot was learned.--_science et nature._ * * * * * le creusot. the members of the american gun foundry board visited these works in , and give the following in their report: the most important steel works in france are situated at le creusot, and bear the name of the location in which they are situated. these works have advanced year by year in importance and in magnitude since their purchase by mr. eugene schneider. this gentleman's death, in , was a source of mourning to the whole town, the inhabitants of which looked up to him as a father. the grateful people have erected to his memory a monument in the market square. under the administration of his son, mr. henry schneider, the fame of the products of the works has been enhanced, and the proportions of the establishment have been much increased. the whole number of workmen now employed here and at other points amounts to , ; and it is the great center of industry of the adjoining region. at no other place in the world is steel handled in such masses. it would be foreign to the purpose of this report to dwell on the many objects of commerce which are supplied from these works, but it is safe to say that no proposed work can be of such magnitude as to exceed the resources of the establishment. for the preparation of metal for cannon and armor-plates le creusot is thoroughly equipped. the iron is produced on the premises from the purest imported ores, and the manufacture of the steel is carried on by the most approved application of the open-hearth system with the siemens furnace; the chemical and mechanical tests are such as to satisfy the most exacting demands of careful government officials; and the executive ability apparent in all the departments and the evident condition of discipline that pervades the whole establishment inspire confidence in the productions of the labor. the capacity for casting steel is represented by seven open-hearth furnaces of tons each, equal to tons; and the process of casting large ingots is a model of order and security. ladles capable of holding the contents of one furnace, mounted upon platform cars, are successively filled at a previously determined interval of time and run on railways to a convenient position over the mould; before the first ladle is exhausted the supply from the succeeding one has commenced to run, and so on to the completion of the casting, the supply to the mould being uninterrupted during the entire process. the precision with which the several ladles are brought into position in succession makes it entirely unnecessary to provide a common reservoir into which all the furnaces may discharge. by this process the casting of a ton ingot, which was witnessed by the board, was effected in minutes. the process of tempering the gun-tubes was also witnessed by the board. the excavation of the pit is, as at st. chamond, meters deep, with the furnace at one end and the oil tank ( tons) at the other. one side of the upright furnace is constructed in the form of a door, which, by a convenient arrangement for swinging, is made to turn on its hinges. thus, when the tube is raised to the right temperature, it is seized by the traveling crane, the door of the furnace swung open, and the tube at once advanced to the tank in which it is immersed. all tubes are immersed in oil the second time, but at a temperature much below that to which they are raised at the first immersion. this process constitutes the annealing after tempering. the manufacture of steel-armor plates is a specialty of le creusot, which is engaged in an active competition with the manufacturers of compound armor. plates up to centimeters in thickness and meters wide are forged here; they are tempered after forging, but what subsequent treatment they receive was not explained. the tempering pit for the plates consists of an excavation of convenient size, in the center of which is placed a tank containing tons of oil. at the four corners of the pit are furnaces in which the plates are raised to a proper temperature. when sufficiently heated, a plate is seized by a walking crane and immersed in the oil. hoops for cannon are manufactured here in large quantities. they are cut from solid ingots, and those for guns up to centimeters are rolled like railway tires; those for larger calibers are forged on a mandrel. jackets of large size are also manufactured; these are made from solid ingots, which, after being forged, are bored out. at le creusot a remarkable test of hoops was witnessed, which exemplifies not only the excellence of the manufacture of the steel but also the exacting character of the french requirements. the hoops for naval guns are made with the interior surface slightly conical. when forged, turned, and brought under a hammer, a standard mandrel of steel, conically shaped to suit the form of the cone in the hoop, but of a slightly increased diameter, is introduced, the smaller end of the mandrel being able to enter the larger end of the hoop. the mandrel is then forced in by the hammer until its lower edge has passed through the hoop. the blows are then made to operate on the upper edge, detaching it from the mandrel. careful measurements are taken of the diameter of the hoop before and after this test, and it is required that the measurement subsequent to the operation shall show that the hoop has partially, but not entirely, returned to the diameter that it had before the entrance of the mandrel. this would show that there is left to the metal a small margin within its elastic limit. a system of manufacture which can comply with such a refinement of exactitude must be very precise. perhaps the most striking feature at le creusot is the forge, where is assembled an array of steam hammers not equaled in the world, viz.: one ton hammer with a fall of meters. one ton hammer with a fall of meters. one ton hammer with a fall of meters. two ton hammers with a fall of ½ meters. one ton hammer with a fall of ½ meters. as the ton hammer at these works is the largest in the world, some particulars concerning it will be appropriate. the foundations are composed of a mass of masonry laid in cement resting on bed rock, which occurs at a depth of meters, an anvil block of cast iron, and a filling-in of oak timber designed to diminish by its elasticity the vibrations resulting from the blows of the hammer. the masonry foundation presents a cube of meters. its upper surface is covered with a layer of oak about one meter in thickness, placed horizontally, on which rests the anvil block. at the perm foundry in russia the anvil block for the ton hammer is made in one piece, moulded and cast on the spot it was intended to occupy. its weight is tons. at le creusot, however, this idea was not approved, and it was determined to construct the block in six horizontal courses, each bedded upon plane surfaces. each course is formed of two castings, except the upper one, a single block, which weighs tons and supports the anvil. thus formed in pieces, it is . meters high, square meters at the base, and square meters at the top. its entire weight is tons. the space between the block and the sides of the masonry in which it rests is filled in solidly with oak. the block is thus independent of the frame of the superstructure. the legs of the frame, inclining toward each other in the form of an a, are secured at their bases to a foundation plate embedded in the masonry. they are hollow, of cast iron, and of rectangular cross section, each leg in two pieces joined midway of their length by flanges and bolts. the legs are also bound together by four plates of wrought iron, which, at the same time, holds the guides. the height of the legs is . meters, and their weight, with the guides, tons. the binding plates weigh together about tons, and the foundation plates tons. the entablature of the frame work weighs tons; on it is placed the steam cylinder, single acting, made in two pieces, each meters long united by flanges and bolts. the diameter of the cylinder is . meters, giving a surface of , square centimeters (deducting the section of the rod, which is centimeters in diameter); which, for atmospheres, gives a pressure under the piston of about tons. as the weight of the hammer is tons, it is evident that it can be raised with great velocity. the stroke of the piston in the cylinder is meters. this height of fall, multiplied by the , kilogrammes of the mass, gives a working force of , kilogrammeters, or about , foot tons. the width between the legs is . meters, and the free height under the cross ties meters, thus providing ample space for maneuvering large masses of metal. the entire height of this colossal structure from the base of the masonry foundation to the upper part of the steam cylinder is meters ( feet), but notwithstanding this unfavorable condition for stability and the enormous effect resulting from a shock of , kilogrammeters, everything is so well proportioned that there is but slight vibration. the workman who maneuvers the hammer is placed on a platform on one of the legs, about meters above the floor. he is here protected from the heat reflected from the mass of metal during the operation of forging. * * * * * plan for an elevated railway at paris. elevated railways have been in operation for a long time in new york, berlin, and vienna, and the city of paris has decided to have recourse to this mode of carriage, so indispensable to large cities. the question of establishing a line of railways in our capital has been open, as well known, since . during this period of nearly fourteen years this grave subject has at various times given rise to serious discussions, in which the most competent engineers have taken part, and numerous projects relating to the solution that it calls for have been put forth. the problem to be solved is of the most complex nature, and the engineers who have studied it have not been able to come to an agreement except as regards a small number of points. it may even be said that unanimity exists upon but a single point, and that is that the means of locomotion in paris do not answer the requirements of the public, and that there is an urgent necessity for new ones. the capital question, that of knowing whether the railway to be built shall be beneath or above ground, is not yet settled; for, up to the present, no project has been prescribed in one direction or the other. while some extol the underground solution as being the only one that, without interfering with circulation in the streets, permits of establishing a double-track railway capable of giving passage to ordinary rolling stock and of connecting directly with the large lines, others, objecting that such a road could not give satisfaction to the taste of parisians, and that it would necessitate work out of proportion to the advantages gained, conclude upon the adoption of an open air railway. preferences generally are evidently for this latter solution. we have received from a learned engineer, mr. jules garnier, a project for an elevated railway, which appears to us to be very ably conceived, very well studied out, and which we hasten to make known. ( .) the system is characterized by the following fundamental points: the up and down tracks, instead of being laid alongside of each other, as in an ordinary railway, are superposed upon two distinct platforms forming a viaduct, which is consequently so arranged as to permit of the laying of one of the tracks at its lower part and of the other at its upper. ( .) the system of constructing the viaduct is so combined as to be capable of giving passage upon the road to the rolling stock of the large lines during the stoppage of the daily passenger trains. ( .) the tracks are connected at the extremities by a curve that has the proper incline to compensate for the difference in level between the two, and which has a sufficiently large radius to allow the slope of the track to be kept within the limits admitted. the running of the trains is thus uninterrupted. ( .) when two lines of different directions bisect one another, a special arrangement permits the passengers from one line to pass to the other by means of what is called a "tangent" station, without the trains of one line crossing the tracks of another, the purpose of which arrangement is to avoid those accidents that would inevitably occur through the crossing of a track by the trains of a transverse line. ( .) the rolling stock is arranged in a manner that allows the entrance and exit of the passengers to be effected with great promptness. in ordinary avenues, comprising a roadway and two sidewalks, the elevated railway is placed in the axis of the roadway at a sufficient height to prevent it interfering with the passage of carriages, say ¾ feet above the surface, while in boulevards or avenues of great width, having _contre-allees_[ ] bordered by a double row of trees, it is installed in one of the _contre-allees_. [footnote : paths parallel with the public walks.] in the first case (fig. ), the viaduct is wholly metallic, while in the second it comprises masonry arches surmounted by a metallic superstructure. the viaduct is formed of independent spans supported by metallic piers that rest upon masonry foundations (fig. ). [illustration: fig. .--project for a parisian elevated railway.] [illustration: fig. .--longitudinal elevation.] the line will have three kinds of stations, intermediate, "tangent," and terminal ones. it is at the latter that the two superposed lines are connected by the circular inclined plane. the waiting platforms of the intermediate stations will be formed simply by the widening of the span corresponding to the station. access to these platforms will be had by stairs running up from the edge of the sidewalk. the passengers will make their exit by means of corresponding stairs on the opposite side. (figs and .) [illustration: fig. .--a station.] [illustration: fig. .--transverse section of station.] the tangent stations are placed at the meeting point of two lines, which, instead of crossing each other, are bent inward like an x, the two parts of which will be tangent to the central point. through such arrangements the running of the trains will be continuous, and a traveler reaching one of these stations will be able, upon changing train, to take at his option any one of the three other directions. as may be seen, mr. garnier's project presents conditions which are very favorable to the establishment of an elevated road in the interior of paris. far from injuring the aspect of the great arteries of our metropolis, the viaduct, as it has been conceived, will contribute toward giving them a still more imposing look. if the beautiful is, as has been said, the expression of the useful, an elevated railway, well conceived, may be beautiful. the project of a subterranean railway is attended with great drawbacks, not only as regards the great expense that it would necessitate, but also the difficulties of constructing it. and there is a still graver objection to it, and that is that it would oblige travelers to move like moles in dark, cold, and moist tunnels. at paris, where we are accustomed to a pleasant climate and clear atmosphere, we like plenty of air and broad daylight.--_la nature._ * * * * * engineering inventions since .[ ] [footnote : address of sir frederick joseph bramwell, f.r.s., on his election as president of the institution of civil engineers. january , .] by sir f. j. bramwell. i propose to devote the very limited time at my disposal to the consideration of some of the most important of those improvements which are obviously and immediately connected with civil engineering. i am aware of the danger there is of making a serious mistake, when one excludes any matter which at the moment appears to be of but a trivial character. for who knows how speedily some development may show that the judgment which had guided the selection was entirely erroneous, and that that which had been passed over was in truth the germ of a great improvement? nevertheless, in the interests of time some risk must be run, and a selection must be made; i propose, therefore, to ask your attention while i consider certain of (following the full title of division i.) "the apparatus, appliances, processes, and products invented or brought into use since ." in those matters which may be said to involve the principles of engineering construction, there must of necessity be but little progress to note. principles are generally very soon determined, and progress ensues, not by additions to the principles, but by improvement in the methods of giving to those principles a practical shape, or by combining in one structure principles of construction which had been hitherto used apart. therefore, to avoid the necessity of having a pause, in referring to a work, by finding that one is overstepping the boundary of principle, and trenching within the domain of construction, i think it will be well to treat these two heads together. if my record had gone back to just before (the date of the great exhibition), i might have described much progress in the principles of girder construction; for shortly prior to that date, the plain cast-iron beam, with the greater part of the metal in the web, and with but little in the top and bottom flange, was in common use; and even in the preparation of the building for that exhibition, it is recorded that one of the engineers connected therewith had great difficulty in understanding how it was that the form of open work girder, with double diagonals introduced therein (a form which was for years afterward known as the exhibition girder), was any stronger than a girder with open panels separated by uprights, and without any diagonals. but, long before , the warren and other truss-girders had come into use, and i am inclined to say that, so far as novelty in the principle of girder-construction is concerned, i must confine myself to that combination of principles which is represented by the suspended cantilever, of which the forth bridge, only now in course of construction, affords the most notable instance. it is difficult to see how a rigid bridge, with , foot spans, and with the necessity for so much clear headway below, could have been constructed without the application of this principle. bridge construction. pursuing this subject of bridge work, the st. louis bridge of mr. eads may, i think, be fairly said to embody a principle of construction novel since , that of employing for the arch-ribs tubes composed of steel staves hooped together. further, in suspension bridges there has been introduced that which i think is fairly entitled to rank among principles of construction, the light upper chain, from which are suspended the linked truss-rods, doing the actual work of supporting the load, the rods being maintained in straight lines, and without the flexure at the joints due to their weight. in the east river bridge, new york, there was also introduced that which i believe was a novelty in the mode of applying the wire cables. these were not made as untwisted cables and then hoisted into place, thereby imposing severe strains upon many of the wires composing the cable through their flexure over the saddles and elsewhere, but the individual wires were led over from side to side, each one having the length appropriate to its position, and all, therefore, when the bridge was erected, having the same initial strain and the same fair play. within the period we are considering, the employment of testing-machines has come into the daily practice of the engineer; by the use of these he is made experimentally acquainted with the various physical properties of the materials he employs, and is also enabled in the largest of these machines to test the strength and usefulness of these materials, when assembled into forms, to resist strains, as columns or as girders. i of course do not for one moment mean to say that experimental machines were unknown or unused prior to --chain cable testing-machines are of old date, and were employed by our past president, mr. barlow, and by others, in their early experiments upon steel; but i speak of it as a matter of congratulation that, in lieu of such machines being used by the few, and at rare intervals upon small specimens, for experimental purposes, they are now employed in daily practice and on a large scale. in harbor work we have had the principle of construction employed by mr. stoney at dublin, where cement masonry is moulded into the form of the wall for its whole height and thickness, and for such a length forward as can be admitted, having regard to the practical limit of the weight of the block, and then, the block being carried to its place, is lowered on to the bottom, which has been prepared to receive it, and is secured to the work already executed by groove and tongue. it would not be right, even in this brief notice of such a mode of construction, to omit mention of the very carefully thought out apparatus by which the blocks are raised off the seats whereon they have been made, and are transported to their destination. it is no simple undertaking (even in these days) to raise (otherwise than hydraulically) a weight of tons, which is the weight of the blocks with which mr. stoney deals. but he does this by means of pulley-blocks attached to shears built on the vessel which is to transport the block, and he contrives to lift the weight without putting upon his chains the extra strain due to the friction of the numerous pulleys over which they pass. the height of the lift is only the few inches needed to raise the block clear of the quay on which it has been formed, and this is obtained by winding up the chain by steam gear quite taut, so as to take a considerable strain, but not that equal to the weight of the block, and then water is pumped into the opposite end of the vessel to that upon which the shears are carried, this latter end rises, and the block is raised off the seat on which it was formed, without the chains being put to work to do the actual lifting at all. the vessel, with the block suspended to the shear legs and over the bows, is then ready to be removed to the place where the block has to be laid. a word must here be said about an extremely ingenious mode of dealing with the slack chain, to prevent its becoming fouled, and not paying out properly, when the block is being lowered. this is accomplished by reeving the slack of each chain over two fixed sets of multiple sheaves. a donkey-engine works a little crab having a large drum, the chain from which is connected with the main chain, and draws it round the multiple sheaves so as to take up the slack as fast as the main crab gives it out. the steam is always on the donkey, which is of such limited dimensions that it can do no injury to the chain even when its full power is in vain endeavoring to draw it any further; directly, however, the main crab gives more slack, and the chain between it and the two sets of sheaves falls into a deeper catenary, and one which therefore puts less opposition to the motion of the donkey-engine, that engine goes to work and makes a further haul upon the slack, and in this way, and automatically, the slack is kept clear. pneumatic foundations. a noteworthy instance of the use of pneumatic appliances in cylinder sinking for foundations is that in progress at the forth bridge. the wrought-iron cylinders are feet in diameter at the cutting-edge, and have a taper of about in . they are, however, at a height of foot above low water (that is, at the commencement of the masonry work of the pier) reduced to feet in diameter; at their bottoms there is a roofed chamber, into which the air is pumped, and in which the men work when excavating, this roof being supported by ample main and cross lattice girders. shafts with air-locks and pipes for admitting water and ejecting silt are provided. the air-locks are fitted with sliding doors, worked by hydraulic rams, or by hand, the doors being interlocked in a manner similar to that in which railway points and signals are interlocked, so that one door cannot be opened until the other is closed. the hoisting of the excavated material is done by a steam engine fixed outside the lock, this engine working a shaft on which there is a drum inside the lock, the shaft passing air-tight through a stuffing box. a separate air-lock, with doors, ladder, etc., complete, is provided to give ingress and egress for the workmen. i have already adverted to one scotch bridge; i now have to mention another, viz., the tay bridge, also now in course of construction. here the cylinders are sunk, while being guided, through wrought-iron pontoons, which are floated to their berths, and are then secured at the desired spot by the protrusion, hydraulically, of four legs, which bear upon the bottom, and thus, until they are withdrawn, convert the pontoon from a floating into a fixed structure. subaqueous engineering. i regret that time will not admit of my giving any description of the modes of "cut and cover" which have been proposed for the performance of subaqueous works; sometimes the proposition has been to do this by means of coffer-dams, and with the work therefore open to the day-light during execution, and sometimes by movable pneumatic appliances. consideration of subaqueous works necessarily leads the mind to appliances for diving, and although its date is considerably anterior to , i feel tempted, as i believe the construction is known to very few of our members, to say a few words about the diving apparatus known as the "bateau-plongeur," and used at the "barrage" on the nile. this consists of a barge fitted with an air-tight cabin provided with an air-lock, and having in the center of its floor a large oval opening, surrounded by a casing standing up above the water-line. in this casing, another casing slides telescopically, the upper part of which is connected to the top of the fixed casing by a leather "sleeve." when it is desired to examine the bottom of the river, the telescopic tube is lowered till it touches the bottom, and then air is pumped into the cabin until the pressure is sufficient to drive out the water, and thus to expose the bottom. this appears to be a very convenient arrangement for shallow draughts of water. reverting for a moment to mr. stoney's work, i may mention that he uses for the greatest depths he has to deal with, when preparing the bed to receive his blocks, a diving apparatus which (while easily accessible at all times) dispenses with the necessity of raising and lowering, needed in an ordinary diving-bell to allow of the entrance and exit of the workmen. mr. stoney employs a bell of adequate size, from the summit of which rises a hollow cylinder, furnished at the top with an air-lock, by which access can be obtained to the submerged bell. beyond the general improvement in detail and in the mode of manufacture, and with the exception of the application of the telephone, there is probably not much to be said in the way of invention or progress in connection with the ordinary dress of the diver. the fleuss diving apparatus. but one great step has been made in the diver's art by the introduction of the chemical system of respiration, the invention of mr. fleuss. he has succeeded in devising a perfectly portable apparatus, containing a chemical filter, by means of which the exhaled breath of the diver is deprived of its carbonic acid; the diver also carries a supply of compressed oxygen from which to add to the remaining nitrogen oxygen, in substitution for that which has been burnt up in the process of respiration. armed with this apparatus, a diver is enabled to follow his vocation without any air-tube connecting with the surface, indeed without any connections whatever. a notable instance of a most courageous use of this apparatus was afforded by a diver named lambert, who, during one of the inundations which occurred in the construction of the severn tunnel, descended into the heading, and proceeding along it for some yards (with the water standing some feet above him), closed a sluice door, through which the water was entering the excavations, and thus enabled the pumps to unwater the tunnel. altogether, on this occasion, this man was under the water, and without any communication with those above, for one hour and twenty-five minutes. the apparatus has also proved to be of great utility in cases of explosion in collieries, enabling the wearer to safely penetrate the workings, even when they have been filled with the fatal choke-damp, to rescue the injured or to remove the dead. construction of tunnels. with respect to the subject of tunneling thus incidentally introduced, in subaqueous work of this kind, i have already alluded to that which is done by "cut and cover," but where the influx of water is a source of great difficulty, as it was in the old thames tunnel (though in this case for water one should read silt or mud), i do not know that anything has been devised so ingenious as the thames tunnel shield; improvement has, however, been made by the application of compressed air. in the instance of the hudson river tunnel, the work was done in the manner proposed so long ago as the year by lord cochrane (earl dundonald) in that specification of his, no. , , wherein he discloses, not merely the crude idea, but the very details needed for compressed air cylinder-sinking and tunneling, included air-locks and hydraulically-sealed modes for the introduction and extraction of materials. i may, perhaps, be permitted to mention that some few years ago i devised for a tunnel through the water-bearing chalk a mode of excavation by the use of compressed air to hold back the water, and combined with the employment of a tunneling machine. this work, i regret to say, was not carried out. but there are, happily, cases of subaqueous tunneling where the water can be dealt with by ordinary pumping power, more or less extensive, and where the material is capable of being cut by a tunneling machine. this was so in the mersey tunnel, and would be in the channel tunnel. in the mersey tunnel, and in the experimental work of the channel tunnel, colonel beaumont and major english's tunneling machine has done most admirable work. in the foot inch diameter heading, in the new red sandstone of the mersey tunnel, a speed of as much as yards forward in twenty-four hours has been averaged, while a maximum of - / yards has been attained; while in the foot heading for the channel tunnel, in the gray chalk, a maximum speed of as much as yards forward in the twenty-four hours has been attained on the english side; and with the later machine put to work at the french end, a maximum speed of as much as - / yards forward in the twenty-four hours has been effected. in ordinary land tunneling since there has been great progress, by the substitution of dynamite and preparations of a similar nature for gunpowder, and by the improvements in the rock-drills worked by compressed air, which are used in making the holes into which the explosive is charged. for boring for water, and for many other purposes, the diamond drill has proved of great service, and most certainly its advent should be welcomed by the geologist, as it has enabled specimens of the stratum passed through to be taken in the natural, unbroken condition, exhibiting not only the material and the very structure of the rock, but the direction and the angle of the dip of the beds. closely connected with tunneling machines are the machines for "getting" coal. this "getting," when practiced by manual labor, involves, as we know, the conversion into fragments and dust of a very considerable portion of the underside of the seam of coal, the workman laboring in a confined position, and in peril of the block of coal breaking away and crushing him beneath it. coal-getting machines, such as those of the late mr. firth, worked by compressed air, reduce to a minimum the waste of coal, relieve the workman of a most fatiguing labor in a constrained position, and save him from the danger to which he is exposed in the hand operation. it is a matter of deep regret on many grounds, but especially as showing how little the true principles of political economy are realized by working men, who are usually well informed on many other points, that the commercial failure of these machines is due to their opposition. in connection with colliery work, and indeed in connection with explosives, in the sense of a substitution for them of sources of expansion acting more slowly, mention should be made of the hydraulic wedges. the employment of these in lieu of gunpowder, to force down the block of coal that had been undercut, is one of the means to be looked to for diminishing the explosions in collieries. another substitute for gunpowder is found in the utilization of the expansion of lime when wetted. this has given birth to the lime cartridge, the merits of which are now universally recognized, but it is feared that trade prejudices may also prevent its introduction. while on this subject of "accidents in mines," it will be well to call attention to the investigations that have been made into the causes of these disasters, and into the probable part played by the minute dust which prevails to so great an extent in dry collieries. the experiments of our honorary member, sir frederick abel, on this point have been of the most striking and conclusive character, and corroborate investigations of the late macquorn rankine into the origin of explosions in flour mills and rice mills, which had previously been so obscure. the name of mr. galloway should also be mentioned as one of the earliest workers in this direction. at first sight, pile driving appears to have but little connection with explosives, but it will be well to notice an invention which has been brought into practical use, although not largely (in this country at all events), for driving piles, by allowing the monkey to fall on a cartridge placed in the cavity in the cap on top of the pile; the cartridge is exploded by the fall, and in the act of explosion drives down the pile and raises the monkey; during its ascent, and before the completion of its descent, time is found for the removal of the empty cartridge and the insertion of a new one. canals and river improvements. in the days of brindley and of smeaton, and of the other fathers of our profession, whose portraits are on these walls, canals and canalized rivers formed the only mode of internal transit which was less costly than horse traction, and, thanks to their labors, the country has been very well provided with canals; but the introduction of railways proved, in the first instance, a practical bar to the extension of the canal system, and, eventually, a too successful competitor with the canals already made. frequently the route that had been selected by the canal engineer was found (as was to be expected) a favorable one for the competing railway, and the result was, the towns that had been served by the canal were served by the railway, which was thus in a position to take away even the local traffic of the canal. for some time it looked as though canal and canalized river navigations must come to an end; for although heavy goods could be carried very cheaply on canals, and with respect to the many works and factories erected on the canal banks, or on bases connected therewith, there was with canal navigation no item of expense corresponding to the cost of cartage to the railway stations, yet the smallness of the railway rates for heavy goods, and the greater speed of transit, were found to be more than countervailing advantages. but when private individuals have embarked their capital in an undertaking, they do not calmly see that capital made unproductive, nor do they refrain from efforts to preserve their dividends, and thus canal companies set themselves to work to add to their position of mere owners of water highways, entitled to take toll for the use of those highways, the function of common carriers, thus putting themselves on a par with the railway companies, who, as no doubt is within the recollection of our older members, were in the outset legalized only as mere owners of iron highways, and as the receivers of toll from any persons who might choose to run engines and trains thereon, a condition of things which was altered as soon as it was pointed out that it was utterly incompatible either with punctuality or with safe working. this addition to the legal powers of the canal companies, made by the acts of and , has had a very beneficial effect upon the value of their property, and has assisted to preserve a mode of transport competing with that afforded by the railways. further, the canal proprietors have from time to time endeavored to improve the rate of transport, and with this object have introduced steam in lieu of horse haulage, and by structural improvements have diminished the number of lockages. many years before the period we are considering, there was employed, to save time in the lockages and to economize water, the system of inclined planes, where, either water-borne in a traveling caisson, as on the monklands incline, or supported on a cradle, as in the incline at newark, in the state of new jersey, the barges were transferred from one level to another; but an important improvement on either of these modes of overcoming a great difference of level is the application of direct vertically lifting hydraulic power. a notable instance of this system was brought before the institution in a paper read on the "hydraulic canal lift at anderton, on the river weaver," by s. duer,[ ] and another instance exists on the canal de new fosse, at fontinettes, in france, the engineers being messrs. clark and standfield, who have other lifts in progress. this system reduces the consumption of water and the expenditure of time to a minimum. [footnote : minutes of proceedings inst. c. e., vol. xlv., p. .] with respect to canalized rivers, the difficulty that must always have existed when these rivers (as was mostly the case) were provided with weirs to dam up the water for giving power to mills has been augmented of late years by the change in the character of floods. it has frequently been suggested that in these days of steam motors in lieu of water power, and of railways in lieu of water carriage, the injury done by obstructing the delivery of floods is by no means compensated by the otherwise all but costless power obtained, or by the preservation of a mode of transport competing with railways. it has thereupon been suggested that it would be in the interests of the community to purchase and extinguish both the manufacturing and the navigating rights, so as to enable the weirs to be removed, and free course to be provided for floods. it need hardly be said, however, that if means could be devised for giving full effect to the river channels for flood purposes, while maintaining them for the provision of motive power and of navigation, it is desirable that this should be done. the great step in this direction appears to be the employment of readily or, it may be, of automatically movable weirs. two very interesting papers on this subject by messrs. vernon-harcourt and e. b. buckley were read and discussed in the session - . these dealt, i fear exclusively, with foreign, notably with french and indian, examples. i say i fear, not in the way of imputing blame to the authors for not having noticed english weirs, but because the absence of such notice amounts to a confession of backwardness in the adoption of remedial measures on english rivers. an instance, however, of improvement since then has been the construction by mr. wiswall, the engineer to the bridgewater navigation company (on the mersey and irwell section of that navigation), of the movable throstle nest weir at manchester. it does seem to me that by the adoption of movable weirs, rivers in ordinary times may be dammed up to retain sufficient water to admit of a paying navigation and water for the mills on their banks; while in time of flood they shall allow channels as efficient for relief as if every weir had been swept away. but the great feature of late years in canal engineering is not the preservation or improvement of the ordinary internal canal, but the provision of canals, such as the completed suez canal, the panama canal in course of construction, the contemplated isthmus of corinth canal--all for saving circuitous journeys in passing from one sea to another; or in the case nearer home of the manchester ship canal, for taking ocean steamers many miles inland. but the old fight between the canal engineer and the railway engineer, or, more properly speaking, between the engineer when he had his canal "stop" on and the same individual when he has his railway "stop"--you will see that i am borrowing a figure, either from dombey & son, where mr. feeder, b.a., is shown to us with his herodotus "stop" on, or, as is more likely, i am thinking of the organs to be exhibited in the second division, "music," of that exhibition of which i have the honor to be chairman--i am afraid this is a long parenthesis breaking the continuity of my observations, which related to the old rivalry between canal and railway engineering. i was about to say that this rivalry was revived, even in the case of the transporting of ocean vessels from sea to sea, for we know that our distinguished member, mr. eads, is proposing to connect the atlantic and pacific oceans by means of a ship railway across the isthmus of panama. he suggests that the largest vessels should be raised out of the water, in the manner commonly employed in floating docks, and should then be transferred to a truck-like cradle on wheels, fitted with hydraulic bearing blocks (this being, however, not a new proposition as applied to graving docks), so as to obtain practical equality of support for the ship, notwithstanding slight irregularities in the roadway, while he proposes to deal with the question of changes of direction by the avoidance of curves and by the substitution of angles, having at the point of junction of the two sides turntables on which the cradle and ship will be drawn; these can be moved with perfect ease, notwithstanding the heavy load, because the turntable will be floating in water carried in circular tanks. the question of preserving the level of the turntable, whether unloaded, partially loaded, or loaded, is happily met by an arrangement of water ballast and pumping. i cannot pass away from the mention of mr. eads' work without just reminding you of the successful manner in which he has dealt with the mouth of the mississippi, by which he has caused that river to scour and maintain a channel feet deep at low water, instead of that feet deep which prevailed there before his skillful treatment. neither can i refrain from mentioning the successful labors of our friend sir charles hartley, in improving the navigation of that great european river, the danube. i am sure we are all rejoiced to see that one of the lectures of the forthcoming series, that on "inland navigation," is to be delivered by him, and i do earnestly trust he will remember it is his duty to the institution not to leave important and successful works unreferred to because those works happen to be his own. i regret that time does not admit of my noticing the many improved machines for excavating, to be used either below water or on dry land. i also regret, for similar reasons, i must omit all mention of ship construction, whether for the purpose of commerce or of war, a subject that would naturally follow that of rivers and of ship railways and canals, and would have enabled me to speak of the great debt this branch of civil engineering owes to the labors of our late member, william froude, and would have enabled me also to deal with the question of material for ships, and with the question of armor plating, in which, and in the construction of ordnance, our past president, mr. barlow, and myself, as the two lay members of the ordnance committee, are so specially interested. military engineering appliances. the mention of armor plates inevitably brings to our minds the consideration of ordnance, but i do not intend to say even a few words on this head of invention and improvement--a topic to which a whole evening might well be devoted--because only three years ago my talented predecessor in this chair, sir william armstrong, made it the subject of his inaugural address, and dealt with it in so masterly and exhaustive a style as to render it absolutely impossible for me to usefully add anything to his remarks. i cannot, however, leave this branch of the subject without mentioning, not a piece of ordnance, but a small arm, invented since the date of sir william's address. i mean the maxim machine gun. this is not only one of the latest, but is certainly one of the most ingenious pieces of mechanism that has been devised. the single barrel fires the martini-henry ammunition; the cartridges are placed in loops upon a belt, and when this belt is introduced to the gun, and some five or six cartridges have been drawn in by as many reciprocations of a handle, the gun is ready to commence firing. after the first shot, which must be fired by the pulling of a trigger in the ordinary way, the gun will automatically continue to send out shot after shot, until the whole of the cartridges on the belt are exhausted; and if care is taken before this happens to link on to the tail of the first belt the head of a second one, and another belt to this, and so on, the firing will be automatically continuous, and at a rate anywhere between one shot per minute and six hundred shots per minute, dependent on the will of the person in charge of the gun, the whole of the operations of loading, firing, and ejecting the cartridge being performed by the energy of the recoil. this perfectly automatic action enables the man who works the gun to devote his whole attention to directing it, and as it is carried on a pivot and can be elevated and depressed, he can, while the gun is firing, aim the bullets to any point he may choose. since the power of defending seaports has been added to by the application of submarine mines, arranged to be fired by impact alone, or to be fired on impact when (under electrical control) the firing arrangement is set for the purpose, or to be fired electrically from the shore by two persons stationed on cross-bearings, both of whom must concur in the act of explosion. these mines are charged with gun-cotton, the development of which owes so much to sir frederick abel, while for purposes of attack the same material, not yet in practical use for shells, is taken as the charge for torpedoes, which are either affixed to a spar or are carried in the head of a submerged cigar-shaped body. by a compressed air or by a direct steam impulse arrangement these weapons are started on their course and are directed, and then the running is taken up by their own engines operating on screw propellers, driven by a magazine of compressed air contained in the body of the torpedo. means are also provided to maintain the designed level below the water surface. the torpedo may either be projected from the war ship itself or from one of those launches which owe their origin to our member, mr. john isaac thornycroft, who first demonstrated the feasibility of that which was previously considered to be impossible, viz., the obtaining a speed of twenty miles and over from a vessel not more than feet long. experiments have been carried on in the united states by captain ericsson to dispense with the internal machinery of the torpedo, and to rely for its traverse through the water upon the original impulse given to it by a breech-loading gun, carried at the requisite depth below the water level in a torpedo boat. this gun, having a feeble charge of powder at a low gravimetric density, fires the torpedo, and, it is said, succeeds in sending it many yards, and with a sufficient terminal velocity to explode the charge by impact. also, in the united states, experiments have been made with a compressed air gun of feet in length and inches in diameter (probably by this time replaced by a gun of inches in diameter), to propel a dart through the air, in the front of which dart there is a metallic chamber containing dynamite. although no doubt the best engineer is the man who does good work with bad materials, yet i presume we should not recommend any member of our profession to select unsuitable materials with the object of showing how skillfully he can employ them. on the contrary, an engineer shows his ability by the choice of those materials which are the very best for his purpose, having regard, however, to the relative facilities of carriage, to the power of supply in sufficiently large quantities, to the ease with which they can be worked up or built in, and to the cost. uses of cement. probably few materials have been found more generally useful to the civil engineer, in works which are not of metal, than has been portland cement. it should be noticed that during the last twenty-two years great improvements have been made in the grinding and in the quality of the cement. these have been largely due to the labors in england of our member, mr. john grant, to the labors of foreign engineers following in his footsteps, and to the zeal and intelligence with which the manufacturers have followed up the question, from a scientific as well as from a practical point of view, not resting until they were able with certainty to produce a cement such as the engineer needed. i do not know that there is very much to be said in the way of progress (so far as the finished results are concerned) in the materials which portland cement and other mortars are intended to unite. clean gravel and ballast and clean sand are, i presume, very much the same in the year as they were not only in the year , but as they were in the year . the same remark applies to stone and to all other natural building materials; and, indeed, even the artificial material brick cannot in these days be said to surpass in quality the bricks used by the romans in this island nineteen hundred years ago, but as regards the mode of manufacture and the materials employed there is progress to be noted. the brick-making machine and the hoffmann kiln have economized labor and fuel, while attempts have been made, which i trust may prove successful, for utilizing the clay which is to be found in the form of slate in those enormous mounds of waste which disfigure the landscape in the neighborhood of slate quarries. certain artificial stones, moreover, appear at last to be made with a uniformity and a power of endurance, and in respect of these qualities compare favorably with the best natural stone, and still more favorably having regard to the fact that they can be made of the desired dimensions and shape, thus being ready for use without labor of preparation. preservation of wood. reverting to natural materials, there remains to be mentioned that great class, timber. in new countries the engineer is commonly glad to avail himself of this material to an extent which among us is unknown. for here, day by day, owing to the ready adaptability of metals to the uses of the engineer, the employment of wood is decreasing. far, indeed, are we from the practice of not more than a hundred years ago, when it was not thought improper to make the shell of a steam engine boiler of wooden staves. the engineer of to-day, in a country like england, refrains from using wood. he cannot cast it into form, he cannot weld it. glue (even if marine) would hardly be looked upon as an efficient substitute for a sound weld; and the fact is, that it is practically impossible to lay hold of timber when employed for tensile purposes so as to obtain anything approaching to the full tensile strength. if it be desired to utilize metals for such a purpose, they can be swollen out into appropriate "eyes" to receive the needed connection; but this cannot be done with wood, for the only way of making an enlarged eye in wood is by taking a piece that is big enough to form the eye, and then cutting away the superfluous portion of the body. moreover, when too much exposed to the weather, and when too much covered up, wood has an evil habit of rotting, compared with the rapidity of which mode of decay the oxidizing of metals is unimportant. further, one's daily experience of the way in which a housemaid prepares a fire for lighting is suggestive of the undesirability of the introduction of resinous sticks of timber, even although they may be large sticks, into our buildings. many attempts, as we know, have been made to render timber proof against these two great defects of rapid decay and of ready combustibility, and, as it appears to me, it is in these directions alone one can look for progress in connection with timber. with respect to the first, it was only at the last meeting of the institution we presented a telford medal and a telford premium to mr. s. b. boulton for his paper "on the antiseptic treatment of timber," to which i desire to refer all those who seek information on this point. with respect to the preservation from fire of inflammable building materials, the processes, more or less successful, that have been tried are so numerous that i cannot even pretend to enumerate them. i will, however, just mention one, the asbestos paint, because it is used to coat the wooden structures of the inventions exhibition. to the employment of this, i think, it is not too much to say those buildings owed their escape, in last year's very dry summer, from being consumed by a fire that broke out in an exhibitor's stand, destroying every object on that stand, but happily not setting the painted woodwork on fire, although it was charred below the surface. i do not pretend to say that a surface application can enable wood to resist the effects of a continued exposure to fire, but it does appear that it can prevent its ready ignition. (_to be continued._) * * * * * the cathedral of the incarnation. the cathedral of the incarnation, at garden city, n. y., the memorial of mrs. cornelia m. stewart to her husband, alexander t. stewart, was opened april , , by impressive religious ceremonies. at precisely o'clock the chimes in the cathedral tower rang out a clear and resonant peal, and the people thronged into the building through its tower and transept entrances. the effort has been made to reproduce in the cathedral a pure type of the gothic architecture of the thirteenth century, without its ruder and less refined characteristics. the strained and coarse images designed to illustrate "the world, the flesh, and the devil," which seem so strange and unapt to american visitors to the great continental cathedrals, are almost entirely omitted in this reproduction. the carving, too, in deference to the more sensitive tastes and better skill of this age, is far more artistic and natural than in the old originals. flowers in stone are made to resemble flowers, and heads are fashioned after a human pattern, and clusters of figures are modeled in a congruous and modern manner. but aside from changes of this kind, the new and magnificent edifice upon hempstead plains is a perfect example of the elaborate and picturesque gothic structures of mediæval days. it is built of brown sandstone raised in colossal blocks. the spire, floriated richly and graduated with a precise symmetry, rises to an extreme altitude of feet inches. the extreme length is about ft. the massive oaken front doors are carved handsomely, and contain the arms of the stewart family, the clinch family (mrs. stewart's maiden name), the hilton family, and those of bishop littlejohn, the episcopal head of the long island diocese. the porch or tower entrance, which is the main entrance to the building, is paved with white marble. in the center of the floor the stewart arms are enameled in brass, showing a shield with a white and blue check, supported by the figures of a wild briton and a lion. the crest is a pelican feeding its young, and the motto is "_prudentia et constantia_." these heraldic figures are made a special feature of the main aisle. directly in the center of the auditorium floor the stewart and clinch arms are impaled, enameled in brass. on the floor in the choir the hilton arms are placed. they bear the patriotic motto "_ubi libertas ibi patria_," with a deer for a crest. the floor of the ante-chancel presents the arms of the diocese. its insular character is especially prominent. the shield of barry wavy contains three crosslets, the peculiar sign of the cathedral. it is supported by dolphins. the crest is a ship, and under all is the sacred motto, "i will set his dominion in the sea." the workmanship of all these arms is superb. by far the most wonderful works of art in the edifice are the windows of stained glass and the musical facilities. every window presents a theme suggestive of the incarnation. the windows of the porch present several of the old testament characters and events which prefigured the birth of christ, and over the door leading to the nave are figures of adam and eve and of abraham and sarah. the four windows on the south side of the nave show the annunciation, the dream of joseph, the salutation of elizabeth, and the refusal of the stable to the parents of the infant redeemer. in the first window of the transept is presented the inn-keeper's refusal of refuge to joseph and mary. the great window of the south transept, in all about thirty feet high, one of the largest windows in the world, shows the family of jesse, the ancestor of jesus. jesse is resting at full length; above him is king david, and all around are figures of his descendants leading up to the virgin mary with the holy child in her arms. above all, in the apex of the windows, are the emblems used in prophecies of christ's coming. the third window of the south transept shows the nativity, with the babe in the manger. two windows in the choir are chosen with special reference to the regular service of the church. the first represents the appearance of the star in the east to the shepherds of bethlehem, introducing the "gloria in excelsis," and the second shows the presentation of christ in the temple, suggesting the "nunc dimittis," the "magnificat," and the "benedictus." then beautiful representations are given in the north transept windows of the magi bringing gifts to the infant saviour, and the wise men before king herod. the windows of the nave show the flight into egypt, the massacre of the innocents, and the return to nazareth. the north window of the transept is the most magnificent of all. it presents christ in glory, thus suggesting the "te deum." jesus sits enthroned with the angels and archangels, prophets, apostles and martyrs of the church in all ages bending in adoration before him, while the heavenly choir are waving palms and chanting music in honor of heaven's king. the smaller windows under the roof show the hierarchy of heaven indicating by music and dances the joy of the celestial world at the scenes of the incarnation depicted below. upon a bright, sunny day the cathedral is made exquisitely beautiful by the mellowed radiance of these windows. they were designed and manufactured by clayton & bell, of london, and are esteemed to present the perfection of their work. their colors, rich and varied, blend in perfect harmony, and the intricacy of the groupings makes each one as interesting as an oil painting. six different organs have been built in different parts of the building. the most important of these is the great organ in the north apse. it is furnished with four keyboards and stops, with twenty-four combination stops that admit of more than a million combinations of sound. on either side of the choir is another organ, with a fourth of great power in the crypt, a fifth in the tower, and an echo organ built under the vaulting of the roof. this produces a soft and weird music. all the organs are operated from the keyboard of the great apse organ, which also plays the chimes of thirteen bells in the tower. the choir instruments are made to correspond by means of iron tubes filled with wind by a bellows engine in the crypt of the apse. a second engine in the crypt of the tower operates the bellows that inflate the instruments in the crypt, the tower, and the vaulting. all the organs and the chimes are connected by electric wires, about twenty-six miles of which are employed, supplied with electricity by a motor in the tower engine room. sublime and grand are the only terms which can suggest the effect of the volume of harmony produced by these instruments in united action. they were made by hilborne l. roosevelt, of this city. the ante-chancel contains the bishop's throne, the dean's seat, and the stalls of the clergy and canons, all of carved mahogany. a superb work of art is the altar, in the chancel, which is separated from the ante-chancel by a heavy bronze railing. the altar is of statuary marble manufactured by cox & sons, of london. its corner columns are of black marble, supported by others of flecked marble, with panels of sienna and griote. between the panels are rich carvings, done in antwerp, representing the temptation and fall in eden; abraham's offering of his son isaac; moses raising the brazen serpent in the wilderness; the annunciation to the virgin; the birth scene in the stable; the crucifixion and the resurrection. the slab of the altar is inlaid with five crosslets, representing the five wounds, and the symbol "i. h. s." none of the cathedral windows are richer than those which circle the chancel. they present christ as the good shepherd and the apostolic college. an excellent piece of chiseling is done by sibbel, the sculptor of this city, in the panels over the credence. they are figures of the high priest with a slain lamb, the type of the bloody sacrifice, and christ with sheaves of wheat and clusters of grapes, the unbloody sacrifice. beneath them is the text, "thou art a prophet forever after the order of melchisedec." the chancel is paved with red and yellow sienna marble as center pieces, flanked with squares of red griote and white marble, the whole bordered with strips of red and black marble. the ante-chancel is paved with blocks of red griote and verd antique. two magnificent pieces of statuary stand on either side of the transept. the first represents religion holding a little model of the cathedral. the other is an image of hope. they were done by park, the florentine sculptor. in the south apse is the baptistery, built with a tower furnished with chimes. its supporting columns are of languedoc marble clustered with smaller ones of sienna and verd antique. six columns support the dome. each is of a different marble, crowned with sculptured capitals in high relief. the windows are appropriate in theme. they represent noah with the ark; the building of the ark; moses holding the tables of the law; the passage of the red sea; john the baptist; the baptism of the eunuch; st. philip, the deacon; and the baptism of christ. in the center of the room stands the font upon an octagonal base of two steps. its pedestal and bowl are traced with symbolic carvings. over it is a canopy of elaborately carved mahogany drawn into a spire bearing a gold crown, studded with rubies and amethysts. at the foot of the chancel is the pulpit, of bronze, designed by sibbel. its base is surrounded by figures representing hearers of the word. mr. sibbel has incorporated an anachronism in one of these figures that will be exceedingly interesting in coming years. it shows the features of henry g. harrison, of this city, the architect of the cathedral. the lectern stands on the other side of the ante-chancel, representing christ blessing little children. superb bronze columns with brass coronas of natural flowers support the roof of the building. the triforium is carved in the richest style with passion flowers, fuchsias, roses, and lilies. in the crypt below are the robing rooms of the clergy and the choir and the sunday-school room. its windows show the arms of every american diocese. beneath the choir is the chantry, furnished in carved oak. adjoining this room is the famous mausoleum erected to the memory of alexander t. stewart. it is constructed of statuary marble, and consists of fourteen bays, at the angles of which are triple columns of the most richly colored imported marbles arched above the elegantly carved capitals, with open tracery, through which the headlights of the colored glass are seen. the subjects of the thirteen windows relate to the passion, death, resurrection, and subsequent appearances of christ, and are executed in admirable design and color. they were made by heaton, butler & bayne, of london. above the window openings rises a dome-shaped ceiling, in carved marble, with a pendent canopy in the center. the pavement, of black and white marbles, radiates from the center of the sides of this polygonal structure, and a large white urn, delicately draped after sibbel's designs, stands under the pendent canopy. it bears mr. stewart's name. the two entrances to the mausoleum are guarded by open-work bronze gates of elegant design and workmanship.--_n. y. tribune._ * * * * * movable market buildings. the furnishing of food supplies has always been a question of great importance to cities, and there are few of the latter, great or small, where the establishment of markets is not the order of the day. at paris especially, by reason of the massing of the population, which is annually increasing, the multiplicity of the wants to be satisfied renders the solution of this question more and more difficult. the old markets, some of the types of which still exist in various parts of paris, were built of masonry and wood. they were massive structures into which the air and light penetrated with difficulty, and which consequently formed a dangerous focus of infection for those who occupied them, and for the inhabitants of the neighboring houses. so the introduction of iron into the construction of markets will bring about a genuine revolution whose influence will soon make itself felt in all branches of the builder's art. the central markets were to have been built of masonry, and the work had even been begun, when, under the pressure of public opinion, the architect, mr. baltard, was led to use iron. evidently, the metal that permits of covering vast spaces with the use of distant bearing points that present a small surface in plan, and leaves between them wide openings that the sun and air can enter in quantity, was the only thing that was capable of giving the solution sought. so it has been said, and rightly, that the central markets are, as regards the distribution and rational use of materials, the most beautiful of the structures of modern paris. this system of construction at once met with great success, and the old markets are everywhere gradually disappearing, in order to give place to the new style of buildings. notwithstanding their number, the parisian markets long ago became insufficient, and wants increased with such rapidity that it became impossible to supply them. the municipal administration was therefore obliged, especially in populous quarters, to tolerate perambulating peddlers, who carried their wares in hand carts. this system has the drawback that it interferes considerably with travel, and especially in streets where the latter is most active. moreover, the merchants and their goods are exposed to the inclemency of the weather. in other places, where large spaces were utilizable, such as squares and avenues, very light structures, that could be easily put together and taken apart, were erected, and markets were opened in these once or twice a week. this method presents serious advantages. iron markets, in fact, despite the immense progress that they mark, present disadvantages that are inherent to all stationary structures. it is necessary to erect them in populous centers, where land is consequently of great value; and the structure itself is costly. the result is that the prime cost is very great, and this forces the city to charge the merchants high rents, and the consumer has to pay for it. with movable markets, on the contrary, the city can utilize large areas of unproductive ground, and find new resources, although renting the stalls at a minimum price. the expense connected with the structure itself is very small. in fact, the distinguishing character of such structures is their portability--so that the same shed can be used in any number of different places. the principal expense, then, will be for carriage; but it is easy to see that there will always be an economy in their use. this is a fact, moreover, that practice has verified, for it is well known that paris does not get her expenses back from her stationary markets, while the movable ones yield a revenue. on another hand, as stationary markets are costly, it results that they cannot be multiplied as much as necessary, and so a portion of the inhabitants are daily submitted to a loss of time in reaching the one nearest them. finally, from a hygienic standpoint, movable markets present a very great advantage over stationary ones. the latter, in fact, notwithstanding their large open spaces, never get rid of the vitiated air that they contain, and the bad odors that emanate from them are also a source of annoyance and danger to the neighborhood. in movable ones, on the contrary, when the structure is taken apart, the air, sun, and rain disperse all bad odors, and the place is rendered wholesome in an instant. we have now demonstrated what great advantages the city of paris and her population might derive from the establishing of movable markets. it is easy to see that well established structures of this kind would render great services in small towns also. they might entirely replace stationary iron markets, the high cost of which often causes municipalities to preserve their old, inconvenient, and unhealthy structures. as a general thing, market is held but once or twice a week in small towns. in the interior the structure could be taken apart, and the place rendered free. the question, then, is to have a system of construction that shall satisfy the different parts of the programme that we have just laid out, that is to say, strength, lightness, rapidity of erection, and ease of carriage. the shelters that are at present employed for movable markets at paris are very primitive, and are wanting in solidity and convenience. they consist simply of wooden uprights to which are affixed cross-pieces that support an impermeable canvas. in order to render it possible to extend the system of movable markets, it became necessary to first find and study the proper material. during the year the city of paris resolved to make some experiments, and the direction of municipal affairs commissioned mr. andre, director of the neuilly works, to submit to him a plan for a structure that could be easily taken apart. the plan finally proposed seemed to meet all the requirements of the case, and a group of ten structures was erected. the trial that was made of these proved entirely satisfactory. the city then made concession to the neuilly company, for six years, of the market in boulevard richard-lenoir, of those of la reine park, and of the madeleine flower markets. a six months' trial has shown the great resistance of the materials that we are about to describe in detail. the structure is supported by cylindrical hollow iron uprights that are firmly connected with the ground as follows: at the places where they are to be fixed, small catches are inserted in the ground so that their upper surface comes flush therewith. these catches consist of two cast iron sides bolted together, and of a bottom and ends formed of flat iron--the end pieces being bent so as to form cramp irons. each of the sides is provided internally with a projecting piece, and an inclined plane as a wedge. in case the catch becomes filled with dirt, it can be easily cleaned out with a scraper. the iron upright terminates in a malleable cast iron shoe, which is screwed on to it, and which is provided beneath with a projection in the form of a reversed t, the upper part of the horizontal branches of which is beveled off in a direction opposite that of the inclined planes of the catch. this projection enters through the slit and fits into the two wedges, and a simple blow of a hammer suffices to make the adherence perfect. the front and hind uprights differ only in length, and the roof timbers are joined at their upper extremities. the figures so well show how the parts are fitted together as to render an explanation unnecessary. the dimensions of these structures vary from . to . feet in length by . in width and in height. the rafters are prolonged so as to project . feet in front, in order to form a protection for the purchaser. this part of the rafters, as well as the longitudinals, is supported by three curved iron braces, which are put in place as follows: the timbers are provided with a ring fixed by a screw, and one extremity of the brace is inserted into this, while the other is held against the upright by a sliding iron socket. the longitudinal timbers are supported between each two uprights by an iron rod that rests upon a block of stone fixed in the ground. the front ends of the rafters are connected by a longitudinal, feet in length. the structure is covered with waterproof canvas held in place by wooden rods, to which it is attached. the wood employed is pitch pine. an entire market of stalls can be put up in three hours by one workman and four assistants.--_le genie civil._ [illustration: the movable madeleine flower market at paris.] fig. .--general view of a movable market. fig. .--shoes. fig. .--mode of joining the roof timbers. fig. .--iron support. fig. .--section of a shoe inserted in the catch. fig. .--catches. fig. .--waterproof canvas.] * * * * * dinocrates' project. vitruvius relates that the architect dinocrates proposed to alexander the great to carve mount athos in such a way as to give it the shape of a man, whose one hand should support an entire city, and whose other should carry a cup which received all the waters from the mountain, and from which they overflowed into the sea. alexander, charmed with the idea, asked him if this city was to be surrounded by land capable of supplying it with the grain necessary for its subsistence. having ascertained that the provisioning could only be done by sea, alexander said: "dinocrates, i grant the beauty of your project; it pleases me, but i think that any one who should take it into his head to establish a colony in the place you propose would run the risk of being taxed with want of foresight; for, just as a child can neither feed nor develop without the milk of a nurse, so a city cannot increase without fertile fields, have a large population without plenty of food, and allow its inhabitants to subsist without rich harvests; so, while giving the originality of your plan my approval, i have to say to you that i disapprove of the place that you have selected for putting it into execution. but i want you to stay near me, because i shall have need of your services." this gigantic project had doubtless been suggested to the macedonian architect by the singular forms that certain mountains affect. it is not rare, in fact, to see human profiles delineated upon the sky, and this phenomenon especially happens in countries where the folded limestone strata have been broken up in such a way as to give rise to deep valleys perpendicular to the direction of the chain. if we look at these folds from below in an oblique direction, we shall see them superposed upon one another in such a way as to represent figures that recall a human profile. [illustration: fig. . landscape by father kircher.] in the seventeenth century, father kircher conceived the idea of taking up dinocrates' plan upon a small scale, and composed the landscape shown in fig. . the drawing remained engraved for a long time upon a marble tablet set into the wall of cardinal montalte's garden at rome. later on, artists improved and varied this project, as shown in figs. and . by looking at these cuts from the sides of the page, it will be seen that they form human profiles. fig. represents an old woman, and fig. a man whose beard and hair are formed by shrubbery. [illustration: figs. and .--landscapes showing profiles of human face.] we do not think that these conceptions have ever been realized, although heron in his treatise on dioptra, and father scott in his parastatic magic, have described instruments that permit of making the necessary outlines to cause grounds to present a given aspect from a given point. these instruments consist essentially of a vertical transparent frame upon which is drawn a vertical projection of the landscape that it is desired to obtain. * * * * * in the island of goa, near bombay, there is a singular vegetable called "the sorrowful tree," because it only flourishes in the night. at sunset no flowers are to be seen, and yet after half an hour it is full of them. they yield a sweet smell, but the sun no sooner begins to shine upon them than some of them fall off, and others close up; and thus it continues flowering in the night during the whole year. * * * * * the cruto incandescent lamp. an electrical exhibition on a comparatively small scale was opened in paris, march , , with considerable eclat, the president of the republic being present. engines to the extent of h.p. are employed to work the lights. among the exhibits is the cruto light. _engineering_ says: at the first glance it presents the same appearance as an edison lamp, having the same form of globe, and apparently a similar luminous filament. but this latter is made in an entirely different manner. a platinum wire is employed, / of a millimeter in diameter. this is obtained by the wollaston process, that is to say, a piece of coarse platinum wire is covered with a stout coating of silver, and drawn down till the outside diameter is / millimeter. the silver coating is then dissolved in a bath of nitric acid, and the platinum wire is left behind. this wire is then cut into lengths, bent into a u form, and placed in a glass globe, in which circulates a current of bicarbonated hydrogen obtained by the action of sulphuric acid on alcohol. this gas, previously purified, circulates around the platinum filament, through which an electric current is passed sufficient to bring it to a red heat. this decomposes the gas, and a thin coating of absolutely pure carbon is deposited on the wire. the operation is continued until a sufficient thickness of carbon has been deposited for each type of lamp, and the method of regulating the amount of deposit is effected very simply, and, in fact, almost automatically. indeed, one of the most interesting features of the process is its great simplicity, although it is somewhat more costly than the ordinary methods of producing incandescence lamps. after having been subjected to the action of the gas for two or three hours, the filament is taken from the glass globe, its diameter is carefully measured, the length is calibrated, and it is set on a platinum support, to which it is soldered by a very ingenious process. the filament is then introduced into a second glass globe charged with bicarbonate of hydrogen; it is placed between pincers that hold the carbon near its union with the platinum, and the platinum some millimeters below. these pincers are then thrown into circuit, and a powerful current is passed through the part which is to be soldered. the platinum and carbon become incandescent, the bicarbonate is decomposed, and a fresh deposit of carbon solders the filament to its support. the system thus mounted is placed within the permanent globe, and a vacuum is obtained in the ordinary way, while the testing and finishing details present nothing of special interest. the finished lamp is then photometrically tested, and placed on a support something like the edison mounting. upon it are engraved the working constants. as an ordinary practical result, these lamps, working with volts and . amperes, give a luminous intensity of candles, or the equivalent in luminous spherical intensity of . edison a lamps. this result is interesting, especially as the life of the lamp ranges from to , hours, as was demonstrated by various careful tests made with some lamps; the most valuable trials having taken place at the turin exhibition. after prolonged use, a diminution in the fall of potential is produced, to a more marked degree than in the edison lamp, and the light can be maintained constant by increasing the strength of the current in a proportion that can be determined by means of resistances. the cruto filament examined under the microscope appears to be uniformly magnetic, and is very regular, except at the curved parts where the diameter is slightly diminished, and it is here that rupture generally takes place. the great structural regularity of the filament probably accounts for its high durability, and from the fact that it may be worked with a higher current than probably any other form of incandescence lamp. m. desroziers in a series of experiments obtained as much as carcel spherical luminous value per horse-power; this characteristic is one likely to be of great value in electric lighting by incandescence of high intensity. at present only -candle lamps are made on the cruto system. the carbon filament, when properly prepared, is gray in hue and of metallic appearance; it is built up in very fine laminæ indicating the mode of manufacture. the results obtained with these lamps vary as much as per cent., according to the care bestowed in producing the filament. if traces of air exist in the globe, they very quickly manifest themselves by the surface of the glass becoming blackened, while an increased energy is required to maintain the brightness of the light. in the early days of this lamp it was thought necessary to remove the delicate platinum wire which forms the core of the filament, by raising the strength of the current sufficiently to destroy it in the course of manufacture. this, however, was given up, and the platinum now remains either as a continuous wire or as a series of small separated granules. * * * * * electric light apparatus for military purposes. in the first period of the siege of a stronghold it is of very great importance for the besieged to embarrass the first progress of the attack, in order to complete their own armament, and to perform certain operations which are of absolute necessity for the safety of the place, but which are only then possible. in order to retard the completion of the first parallel, and the opening of the fire, it is necessary to try to discover the location of such parallel, as well as that of the artillery, and to ply them with projectiles. but, on their side, the besiegers will do all in their power to hide their works, and those that they are unable to begin behind natural coverts they will execute at night. it will be seen from this how important it is for the besieged to possess at this stage of events an effective means of lighting up the external country. later on, such means will be of utility to them in the night-firing of long-range rifled guns, as well as for preventing surprises, and also for illuminating the breach and the ditches at the time of an assault, and the entire field of battle at the time of a sortie. [illustration: electric light apparatus for army use.] on a campaign it will prove none the less useful to be provided with movable apparatus that follow the army. a few years ago. lieut. a. cuvelier, in a very remarkable article in the _revue militaire belge_, pointed out the large number of night operations of the war of , and predicted the frequent use of such apparatus in future wars. the accompanying engraving represents a very fine electric light apparatus, especially designed for military use in mountainous countries. it consists of a two-wheeled carriage, drawn by one horse and carrying all the apparatus necessary for illuminating the works of the enemy. the machine consists of the following parts: ( ) a field boiler. ( ) a gramme electric machine, type m, actuated directly by a brotherhood -cylinder motor. ( ) a mangin projector, inches in diameter, suspended for carriage from a movable support. this latter, when the place is reached where the apparatus is to operate, may be removed from the carriage and placed on the ground at a distance of about a hundred yards from the machine, and be connected therewith by a conductor. col. mangin's projector consists of a glass mirror with double curvature, silvered upon its convex face. it possesses so remarkable optical properties that it has been adopted by nearly all powers. the fascicle of light that it emits has a perfect concentration. in front of the projector there are two doors. the first of these, which is plane and simple, is used when it is desired to give the fascicle all the concentration possible; the other, which consists of cylindrical lenses, spreads the fascicle horizontally, so as to make it cover a wider space. the range of the concentrated fascicle is about , feet. the projector may be pointed in all directions, so as to bring it to bear in succession upon all the points that it is desired to illuminate. the -inch projector is the smallest size made for this purpose. the constructors, messrs. sautter, lemonnier & co., are making more powerful ones, up to inches in diameter, with a corresponding increase in the size of the electric machines, motors, and boilers. the various powers make use of these apparatus for the defense of fortresses and coasts, for campaign service, etc. the various parts of the apparatus can be easily taken apart and loaded upon the backs of mules. the only really heavy piece is the boiler, which weighs about pounds. * * * * * electricity and magnetism.[ ] [footnote : introductory to the course of lectures on physics at washington university, st. louis, missouri--_kansas city review._] prof. francis e. nipher. it was known six hundred years before christ that when amber is rubbed it acquires the power of attracting light bodies. the greek name for amber, _elektron_, was afterward applied to the phenomenon. it was also known to the ancients that a certain kind of iron ore, first found at magnesia, in asia minor, had the property of attracting iron. this phenomenon was called magnetism. this is the history of electricity and magnetism for two thousand years, during which these facts stood alone, like isolated mountain peaks, with summits touched and made visible by the morning sun, while the region surrounding and connecting them lay hidden and unexplored. in fact, it is only in more recent times that men could be found possessing the necessary mental qualities to insure success in physical investigation. some of the ancients were acute observers, and made valuable observations in descriptive natural history. they also observed and described phenomena which they saw around them, although often in vague and mystical terms. they, however, were greatly lacking in power to discriminate between the possible and the absurd, and so old wives' tales, acute speculations, and truthful observations are strangely jumbled together. with rare exceptions they did not contrive new conditions to bring about phenomena which nature did not spontaneously exhibit--they did not experiment. they attempted to solve the universe in their heads, and made little progress. in mediæval times intellectual men were busy in trying to set each other right, and in disputing and arguing with those who believed themselves to be right. it was an era of intellectual pugilism, and nothing was done in physics. in fact, this frame of mind is incompatible with any marked success in scientific work. the physical investigator cannot take up his work in the spirit of controversy; for the phenomena and laws of nature will not argue with him. he must come as a learner, and the true man of science is content to learn, is content to lay his results before his fellows, and is willing to profit by their criticisms. in so far as he permits himself to assume the mental attitude of one who defends a position, in so far does he reveal a grave disqualification for the most useful scientific work. scientific truth needs no man's defense, but our individual statements of what we believe to be truth frequently need criticism. it is hardly necessary to remark, also, that critics are of various degrees of excellence, and it seems that those in whom the habit of criticism has become chronic are of comparatively little service to the world. the great harbinger of the new era was galileo. there had been prophets before him, and after him came a greater one--newton. they did nothing of note in electricity and magnetism, but they were filled with the true spirit of science, they introduced proper and reasonable methods of investigation, and by their great ability and distinguished success they have produced a revolution in the intellectual world. other great men had also appeared, such as leibnitz and huyghens; and it became very clear that the methods of investigation which had borne such fruit in the days of galileo were not disposed of completely by his unwilling recantation; it became very clear that the new civilization which was dawning upon europe was not destined to the rude fate which had overwhelmed the brilliant scientific achievements of the spanish moors of a half century before. already in , about the time when galileo entered pisa as a student, borroughs had determined the variation of the magnetic needle at london, and we have upon the screen a view of his instrument, which seems rude enough, in comparison with the elaborate apparatus of our times. the first great work on electricity and magnetism was the "de magnete" of gilbert, physician of queen elizabeth, published in . galileo, already famous in europe, recognized in the methods of investigation used by gilbert the ones which he had found so fruitful, and wrote of him, "i extremely praise, admire, and envy this author." gilbert made many interesting contributions to magnetism, which we shall notice in another lecture, and he also found that sulphur, glass, wax, and other bodies share with amber the property of being electrified by friction. he concluded that many bodies could not be thus electrified. gray, however, found in that these bodies were conductors of electricity, and his discoveries and experiments were explained and described to the president of the royal society while on his death bed, and only a few hours before his death. if precautions are taken to properly insulate conductors, all bodies which differ in any way, either in structure, in smoothness of surface, or even in temperature, are apparently electrified by friction. in all cases the friction also produces heat, and if the bodies rubbed are exactly alike, heat only is produced. an electrified body will attract all light bodies. this gutta percha when rubbed with a cat's skin attracts these bits of paper, and this pith ball, and this copper ball; it moves this long lath balanced on its center, and deflects this vertical jet of water into a beautiful curve. if a conductor is to be electrified, it must be supported by bad conductors. this brass cylinder standing on a glass column has become electrified by friction with cat's-skin. my assistant will stand upon this insulating stool, and by stroking his hand you will observe that with his other hand he can attract this suspended rod of wood, and you will hear a feeble spark when i apply my knuckle to his. du fay, of paris, discovered what he called two kinds of electricity. he found that a glass rod rubbed with silk will repel another glass rod similarly rubbed, but that the silk would attract a rubbed glass rod. we express the facts in the well-known law that like electricities repel each other, and unlike attract. for a long time the nature of the distinctions between the two electricities was not understood. it was found later that when the two bodies are rubbed together they become oppositely electrified, and that the two electricities are always generated in equal quantity; so that if the two bodies are held in contact after the rubbing has ceased the two electricities come together again and the electrical phenomena disappear. they have been added together, and the result is zero. franklin proposed to call these electricities positive and negative. these names are well chosen, but we do not know any reason why one should be called positive rather than the other. the electricity generated on glass when rubbed with silk is called positive. let us now examine the distinction between positive and negative electricities somewhat more closely, aiding ourselves by two cases which are somewhat analogous. two air-tight cylinders, a and b, contain air at ordinary pressure. the cylinders are connected by a tube containing an air-pump in such a way that, when the pump is worked, air is taken from a and forced into b. to use the language of the electricians, we at once generate two kinds of pressure. the vessels have acquired new properties. if we open a cock in the side of either vessel, we hear a hissing sound, if a light body is placed before the opening in a it would be attracted, and before the opening in b it would be repelled. now this is only roughly analogous to the case of the electrified bodies, but the analogy will nevertheless aid us in our study. if the two vessels are first connected with the air, and then closed up and the pump is set to work, we increase the pressure in b and diminish the pressure in a. to do this requires the expenditure of a quantity of work. if the cylinders are connected by an open tube--a conductor--the difference in pressure disappears by reason of a flow of gas from one vessel to the other. if we had a pump by means of which we could pump heat from one body into another, starting with two bodies at the same temperature, the temperature of one body would increase and that of the other would diminish. if we knew less than we do of heat, we might well discuss whether the plus sign should be applied to the heat or to the cold, because these names were coined by people who knew very little about the subject except that these bodies produce different sensations when they come in contact with the human body. furthermore, we find that whether the hand is applied to a very hot body or to a very cold body, the physiological effect is the same. in each case the tissue is destroyed and a burn is produced. shall we now say that this burn is produced by an unusual flow of heat from the hot body to the hand, or from the hand to the cold body, or shall we say that it is due to an unusual flow of cold from the cold body to the hand, or from the hand to the hot body? logically these expressions are identical; still we have come to prefer one of them. it is because we have learned that in those bodies which our fathers called hot, the particles are vibrating with greater energy than in cold bodies, that we prefer to say that heat is added and not cold subtracted, when a cold body becomes less cold. now to come back to our electrified bodies. let us suppose that this gutta percha, and this cat's-skin are not electrified. that means that their electrical condition is the same as that of surrounding bodies. let us also suppose that their thermal condition is the same as surrounding bodies, ourselves included--that is, they are neither hot nor cold. we express these conditions in other words by saying that the bodies have the same electrical _potential_ and the same temperature. temperature in heat is analogous to potential in electricity. as soon as adjacent bodies are at different temperatures, we have the phenomena which reveal to us the existence of heat. as soon as adjacent bodies have different electrical potentials, we have the phenomena which reveal the existence of electricity. as soon as adjacent regions in the air are at different pressures, we have phenomena which reveal the existence of air. bodies all tend to preserve the same temperature and also the same electrical potential. any disturbances in electrical equilibrium are much more quickly obliterated than in case of thermal equilibrium, and we therefore see less of electrical phenomena than of thermal. in thunder storms we see such disturbances, and with delicate instruments we find them going on continuously. changes in temperature occurring on a large scale in our atmosphere, occurring in these gas jets, in our fires, in the axles of machinery, and in thousands of other places, are so familiar that we have ceased to wonder at them. if we rub these two bodies together, the potential of the two is no longer the same. we do not know which one has become greater, and in this respect our knowledge of electricity is less complete than of heat. we assume that the gutta percha has become negative. if we now leave these bodies in contact, the potential of the cat's skin will diminish and that of the gutta percha will increase until they have again reached a common potential--that of the earth. as in the case of heat and cold, we may say either that this has come about by a flow of positive electricity from the cat's skin to the gutta percha, or by a flow of negative electricity in the opposite direction, for these statements are identical. in case of our gas cylinders, the gas tends to leak out of the vessel where the pressure is great into the vessel where it is small. the heat tends to leak out of a body of high temperature into the colder one, or the cold tends to go in the opposite direction. similarly, the plus electricity tends to flow from the body having a high potential, to the body having a low potential, or the minus electricity tends to go in the opposite direction. * * * * * [engineering.] the hydrodynamic researches of professor bjerknes. by conrad w. cooke. [illustration: fig. .] we have in former articles described the highly interesting series of experimental researches of dr. c. a. bjerknes, professor of mathematics in the university of christiania, which formed so attractive a feature in the electrical exhibition of paris in , and which constituted the practical development of a theoretical research which had extended over a previous period of more than twenty years. the experiments which we described in those articles were, as our readers will remember, upon the influence of pulsating and rectilinear vibrating bodies upon one another and upon bodies in their neighborhood, as well as upon the medium in which they are immersed. this medium, in the majority of professor bjerknes earlier experiments, was water, although he demonstrated mathematically, and to a small extent experimentally, that the phenomena, which bear so striking an analogy to those of magnetism, may be produced in air. our readers will recollect that in the spring of mr. stroh, by means of some very delicate and beautifully designed apparatus, was able to demonstrate a large number of the same phenomena in atmospheric air of the ordinary density; and about the same time professor bjerknes, in christiania, was extending his researches to phenomena produced by a different class of vibrations, namely, those of bodies moving in oscillations of a circular character, such, for example, as a cylinder vibrating about its own axis or a sphere around one of its diameters; some of these experiments were brought by professor bjerknes before the physical society of london in the following june. since that time, however, professor bjerknes, with the very important assistance of his son, mr. vilhelm bjerknes, has been extending these experimental researches in the same direction, and with the results which it is the object of the present series of articles to describe. [illustration: fig. .] the especial feature of interest in all professor bjerknes experiments has been the remarkably close analogy which exists between the phenomena exhibited in his mechanical experiments in water and other media and those of magnetism and of electricity, and it may be of some interest if we here recapitulate some of the more striking of these analogies. ( .) in the first place, the vibrating or pulsating bodies, by setting the water or other medium in which they are immersed into vibration, set up in their immediate neighborhood a field of mechanical force very closely analogous to the field of magnetic force with which magnetized bodies are surrounded. the lines of vibration have precisely the same directions and form the same figures, while at the same time the decrease of the intensity of vibration by an increase of distance obeys precisely the same law as does that of magnetic intensity at increasing distances from a magnetic body. ( .) when two or more vibrating bodies are immersed in a fluid, they set up around them fields of vibration, and act and react upon one another in a manner closely analogous to the action and reaction of magnets upon one another, producing the phenomena of attraction and repulsion. in this respect, however, the analogy appears to be inverse, repulsion being produced where, from the magnetic analogy, one would expect to find attraction, and _vice versa_. ( .) if a neutral body, that is to say a body having no vibration of its own, be immersed in the fluid and within the field of vibration, phenomena are produced exactly analogous to the magnetic and diamagnetic phenomena produced by the action of a magnet upon soft iron or bismuth, its apparently magnetic or diamagnetic properties being determined by the specific gravity of the neutral body as compared to that of the medium in which it is immersed. if the neutral body be lighter than the medium, it exhibits the magnetic induction of iron with respect to polarity, but is nevertheless repelled; while if it be heavier than the medium, its direction is similar to that of diamagnetic bodies such as bismuth, but on the other hand exhibits the phenomena of attraction. in this way professor bjerknes has been able to reproduce analogues of all the phenomena of magnetism and diamagnetism, those phenomena which may be classed as effects of induction being directly reproduced, while those which may be classed as effects of mechanical action, and resulting in change of place, are analogous inversely. this fact has been so much misunderstood both in this country and on the continent that it will be well, before describing the experiments, to enter more fully into an explanation of these most interesting and instructive phenomena. for the sake of clearness we will speak of magnetic induction as that property of a magnet by which it is surrounded by a field of force, and by which pieces of iron, within that field, are converted into magnets, and pieces of bismuth into diamagnets, and we will speak of magnetic action as the property of a magnet by which it attracts or repels another magnet, or by which it attacks or repels a piece of iron or bismuth magnetized by magnetic induction. [illustration: fig. .] the corresponding hydrodynamic phenomena may be regarded in a similar manner; thus, when a vibrating or pulsating body immersed in a liquid surrounds itself with a field of vibrations, or communicates vibrations to other immersed bodies within that vibratory field, the phenomena so produced may be looked upon as phenomena of hydrodynamic induction, while on the other hand, when a vibrating or pulsating body attracts or repels another pulsating or vibratory body (whether such vibrations be produced by outside mechanical agency or by hydrodynamical induction), then the phenomena so produced are those of hydrodynamical action, and it is in this way that we shall treat the phenomena throughout this article, using the words _induction_ and _direct action_ in these somewhat restricted meanings. [illustration: fig. .] [illustration: fig. .] in the hydrodynamical experiments of professor bjerknes all the phenomena of magnetic induction can be reproduced directly and perfectly, but the phenomena of magnetic action are not so exactly reproduced, that is to say, they are subject to a sort of inversion. thus when two bodies are pulsating together and in the same phase (i. e., both expanding and both contracting at the same time), they mutually attract each other: but if they are pulsating in opposite phases, repulsion is the result. from this one experiment taken by itself we might be led to infer that bodies pulsating in similar phases are the hydrodynamic analogues of magnets having their opposite poles presented to one another, and that bodies pulsating in opposite phases are analogous to a presentation of similar magnetic poles; but it will be seen at once that this cannot be the case if three magnetic poles or three pulsating bodies be considered instead of only two. it is clear, on the one hand, that three similar magnet poles will all repel one another, while, on the other, of three pulsating bodies, two of them must always attract one another, while a third would be repelled; and, moreover, two similarly pulsating bodies set up around them the same lines of force as two similar magnetic poles, and two oppositely pulsating bodies produce lines of force identically the same as those set up by two magnets of opposite polarity. thus it will be seen that there is a break in the analogy between the hydrodynamical and the magnetic phenomena (if a uniform inversion of the effects can be called a break, for it is, as far as professor bjerknes' experiments go, without an exception); and if by any means this inversion could be reinverted, all the phenomena of magnetism and diamagnetism could be exactly reproduced by hydrodynamical analogues; there would thus be grounds for forming a theory of magnetism on the basis of mechanical phenomena, and a very important link in the chain of the correlation of the physical forces would be supplied. while the experiments of professor bjerknes upon pulsating and rectilinearly vibrating bodies and their influence upon one another illustrate by very close analogies the phenomena of magnetism, those upon circularly vibrating bodies and their mutual influences bear a remarkable analogy to electrical phenomena; and it is a significant fact that exactly as in the case of magnetic illustration, the analogies are direct as regards the phenomena of induction, and inverse in their illustration of direct electrical action. if we examine the figure produced by the field of force surrounding a conductor through which a current of electricity is being transmitted (see fig. ), we see that iron filings within that field arrange themselves in more or less concentric circles around the conductor conveying the current. from this fact professor bjerknes and his son, reasoning that, to produce a similar field of energy around a vibrating body, the vibrations of that body must partake of a circular or rotary character, constructed apparatus for producing the hydrodynamic analogue of electric currents, in which a conductor transmitting a current of electricity is represented by a cylinder to which oscillations in circles around its axis are given by suitable mechanical means, so as to cause the enveloping medium to follow its motion and make similar rotative vibrations. in some of the earlier experiments in this direction, cylinders carrying radial veins (a, fig. ) or fluted longitudinally around their surfaces (b, fig. ) were employed with the object of giving the vibrating cylinder a greater hold of the liquid in which they were immersed; but it was found that these vanes or flutings had but little or no effect upon water or liquids of similar viscosity, and professor bjerkes was led to adopt highly viscous fluids, such as glycerin or maize sirup, both of which substances are well adapted for the experiments, being at the same time both highly viscous and perfectly transparent and colorless. in seeking, for the purpose of this research, a fluid medium which shall possess analogous properties to the luminiferous ether, or whatever may be the medium whose vibrations render manifest certain physical phenomena, it might be considered at first sight that substances so dense as glycerin and sirup could have but little in common with the ether, and that an analogy between experiments made within it and phenomena associated with ethereal vibrations would be of a very feeble description: but professor bjerknes has shown that the chief requisite in such a medium is that its viscosity should be great, not absolutely, but large only in proportion to its density, and if the density be small, the necessary viscosity may be small also. neither is it necessary for the fluid medium to possess great internal friction, but what is necessary to the experiments is that the medium shall be one which is readily set into vibration by the action of the circularly vibrating cylinder; this property appears to be possessed exclusively by the more viscous fluids, and is, moreover, in complete accord with what is known of the luminiferous ether according to the theory of light. the property is rather a kind of elasticity, which ordinary fluids do not possess, but which facilitates the propagation of transverse vibrations. one form of apparatus for the propagation of rotative oscillations is shown to the left of fig. , and consists of a cylinder, a, mounted on a tubular spindle, and which is set into circular oscillations around its axis by the little vibrating membrane, c, which is attached to the axis of the cylinder by a little crank and connecting rod shown in detail in fig. . this membrane is set into vibration by a rapidly pulsating column of air contained in a flexible tube m, by which apparatus is connected to the pulsation pump which was employed by professor bjerknes in his earlier experiments. in fig. , a somewhat similar apparatus for producing horizontal vibrations is shown, and marked n h c, the only difference between them being one of mechanical detail necessitated by the change in the position of axis of vibration from the vertical to the horizontal. if circularly vibrating cylinders, such as we have described, be immersed in a viscous fluid and set into action, the following phenomena may be observed: . the effect upon the fluid itself, setting up therein a field of vibration, and corresponding by analogy with the production of a field of force around a wire conveying an electric current. . the effect upon other circularly vibrating bodies within that field of force corresponding to the action and reaction of electric currents upon one another. . the effect on pulsating and oscillating bodies similarly immersed, illustrating the mutual effects upon one another of magnets and electric currents. the first of these effects is one of induction, and, from what has been said from an earlier part of this article, it will be understood that the analogy between the hydrodynamic and the electric phenomena is direct and complete. the effects classified under the second and third heads, being phenomena of direct action (in the restricted use of the word), are uniformly analogous to the magnetic and electric phenomena which they illustrate. (_to be continued._) * * * * * the xylophone. like most musical instruments, the xylophone, had its origin in very remote times. the hebrews and greeks had instruments from which the one of to-day was derived, although the latter has naturally undergone many transformations. along about we find it widely in use in sicily under the name of _xylonganum_. the russians, cossacks, and tartars, and especially the mountain population of the carpathians and ural, played much upon an instrument of the same nature that they called _diereva_ and _saloma_. it appears that the xylophone was played in germany as early as the beginning of the th century. after this epoch it was in use for quite a long period, but gradually fell into oblivion until the beginning of the present century. it was toward that the celebrated russian gussikow undertook a grand artistic voyage through europe, and gained a certain renown and received many honors due to his truly original productions. gussikow possessed a remarkable _technique_ that permitted the musical instrument which he brought into fashion to be appreciated for all its worth. [illustration: fig. .--method of playing upon the xylophone.] as the name, "instrument of wood and straw," indicates, the xylophone (which fig. shows the mode of using) consists of small pieces of wood of varying length, and narrow or wide according to the tone that it is desired to get from them. these pieces of wood are connected with each other by cords so as to form a triangular figure (fig. ) that may be managed without fear of displacing the parts. the whole is laid upon bands of straw designed to bring out the sounds and render them stronger and purer. the sounds are produced by striking the pieces of wood with a couple of small hammers. they are short and jerky, and, as they cannot be prolonged, nothing but pieces possessing a quick rhythm can be executed upon the instrument. dances, marches, variations, etc., are played upon it by preference, and with the best effect. [illustration: fig. .--plan view of the xylophone.] the popularity of this instrument is making rapid progress, and it is beginning to be played in orchestras in france [as it has been in america for many years]. a method of using it has just been published, as well as pieces of music adapted to it, with piano, violin, orchestra, etc., accompaniment. * * * * * electrotyping. this eminently useful application of the art of electrotyping originated with volta, cruickshank, and wollaston about or . in , spencer, of london, made casts of coins, and cast in intaglio from the matrices thus formed; in the same year jacobi, of dorpat, in russia, made casts by electro deposit, which caused him to be put in charge of the work of gilding the dome of st. isaac at st. petersburg. electrotyping for the purposes of printing originated with mr. joseph a. adams, a wood-engraver of new york, who made casts ( - ) from wood-cuts, some engravings being printed from electrotype plates in the latter year. many improvements in detail have been added since, in the processes as well as the appliances. robert murray introduced graphite as a coating for the form moulds. he first communicated his discovery to the royal institution of london, and afterward received a silver medal from the society of arts. blackleading the form. the process of electrotyping is as follows: the form is locked up very tightly, and is then coated with a surface of graphite, commonly known as blacklead, but it is a misnomer. this is put on with a brush, and may be done very evenly and speedily by a machine in which the brush is reciprocated over the type by hand-wheel, crank, and pitman. a soft brush and very finely powdered graphite are used; the superfluous powder being removed, and the face of the type cleaned by the palm of the hand. taking the mould. a shallow pan, known as a moulding pan, is then filled with melted yellow wax, making a smooth, even surface, which is blackleaded. the pan is then secured to the head of the press, and the form placed on the bed, which is then raised, delivering an impression of the type upon the wax. the pan is removed from the head of the press, placed on a table, and then built up, as it is termed. this consists in running wax upon the portions where large spaces occur between type, in order that corresponding portions in the electrotype may not be touched by the inking roller, or touched by the sagging down of the paper in printing. making the deposit. the wax mould being built, is ready for blackleading, to give it a conducting surface upon which the metal may be deposited in the bath, superfluous blacklead being removed with a bellows. blacklead, being nearly pure carbon, is a poor conductor, and a part of the metal of the pan is scraped clean, to form a place for the commencement of the deposit. the back of the moulding is waxed, to prevent deposit of copper thereon, and the face of the matrix is wetted to drive away all films or bubbles of air which may otherwise be attached to the blackleaded surface of the type. the mould is then placed in the bath, containing a solution of sulphate of copper, and is made a part of an electric circuit, in which is also included the zinc element in the sulphuric-acid solution in the other bath. a film of copper is deposited on the blacklead surface of the mould; and when this shell is sufficiently thick, it is taken from the bath, the wax removed, the shell trimmed, the back tinned, straightened, backed with an alloy of type-metal, then shaved to a thickness, and mounted on a block to make it type-high. a recent improvement. has been introduced in which there is added finely pulverized tin to the graphite for facing the wax mould; the effect in the sulphate of copper bath is to cause a rapid deposition of copper by the substitution of copper for the tin, the latter being seized by the oxygen, while the copper is deposited upon the graphite. the film is after increased by the usual means. knight's expeditious process consists in dusting fine iron filings on the wet graphite surface of the wax mould, and then pouring upon it a solution of sulphate of copper. stirring with a brush expedites the contact, and a decomposition takes place; the acid leaves the copper and forms with the iron sulphate a solution which floats off, while the copper is freed and deposited in a pure metallic form upon the graphite. the black surface takes on a muddy tinge with marvelous rapidity. the electric-connection gripper is designed to hold and sustain the moulding pan and make an electric connection with the prepared conducting pan of the mould only, while the metallic pan itself is out of the current of electricity, and receives no deposit. backing-up. the thin copper-plate, when removed from the wax mould, is just as minutely correct in the lines and points as was the wax mould, and the original page of type. but it is obvious that the copper sheet is no use to get a print from. you must have something as solid as the type itself before it can be reproduced on paper. so a basis of metal is affixed to the copper film, and this again is backed up with wood thick enough to make the whole type-high. to get this, a man melts some tinfoil in a shallow iron tray, which he places on the surface of molten lead, kept to that heat in square tanks over ordinary fires. the tinfoil sticks to the back of the copper, and on the back of this is poured melted type-metal, until a solid plate has been formed, the surface of which is the copper facsimile and the body white metal. the electro metal plate, copper colored and bright on its surface, has now to go to the finishing room. here are two departments. in one the plates are shaved and trimmed down to fit the wood blocks, which are made in the other department. some of these operations are done by hand, but it is very interesting to see self-working machines planing the sheets of metal to precisely the required thinness with mathematical exactness. a pointed tool is set to a certain pitch, and the plate of metal is made to revolve in such a way that one continuous curl shaving falls until the whole surface (back) has been planed perfectly true. the wood blocks are treated in the same way, after being sawn into the required sizes by a number of circular saws. another set of workmen fit and join the metal to the wood, trim the edges, and turn the blocks out type-high and ready for working on the printing press. a wet blackleading process. in messrs. harper's establishment in new york, an improved wet process of blackleading is adopted. the wax mould is laid face upward on the floor of an inclosed box, and a torrent of finely pulverized graphite suspended in water is poured upon it by means of a rotary pump, a hose, and a distributing nozzle which dashes the liquid equally over the whole surface of the mould. superfluous graphite is then removed by copious washing, an extremely fine film of graphite adhering to the wax. this answers a triple purpose; it coats the mould with graphite, wets it ready for the bath, and expels air bubbles from the letters. this process prevents entirely the circulation of blacklead in the air, which has heretofore been so objectionable in the process of electrotyping. a new foreign process. the galvanoplastic process of m. coblence for obtaining electrotypes of wood-engravings is as follows: a frame is laid upon a marble block, and then covered with a solution of wax, colophane, and turpentine. this mixture on the frame, after cooling, becomes hard, and presents a smooth, even surface. an engraved wooden block is then placed upon the surface of the frame, and subjected to a strong pressure. the imprint on matrix in cameo, having been coated with graphite, is then placed vertically in a galvanoplastic bath, and a cast, an exact reproduction of the wood-engraving, is obtained. the shell is then backed with type metal and finished in the usual way.--_printer and stationer._ * * * * * a new seismograph. all the seismographs that have hitherto been employed have two grave disadvantages: they are either too simple, so that their indications are valueless, or too complicated, so that their high cost and delicacy, and the difficulty of mounting them and keeping them in order, tend to prevent them from being generally used. seismology will not be able to make any serious progress until it has at its disposal very certain and very numerous data as to telluric movements registered at a large number of points at once by accurate instruments. i have endeavored to construct a simple apparatus capable of automatically registering such facts as it is most necessary to know in scientific researches on the movements of the earth. after numerous experiments i believe that i have succeeded in solving this delicate problem, since my apparatus, put to the test of experience, has given me satisfactory results. i have consequently decided to submit it to the approval of men of science. my seismograph is capable of registering ( ) vertical shocks, ( ) horizontal ones, ( ) the order in which all the shocks manifest themselves, ( ) their direction, and ( ) the hour of the first movement. [illustration: cordenons' seismograph.] the apparatus is represented in the accompanying cut. the horizontal shocks are indicated by the front portion of the system, and the vertical ones by the back portion. the hour of the first shock is indicated as follows: the elastic strip of steel, c, is fixed by one of its extremities to a stationary support, d. when, as a consequence of a vertical motion, the free extremity of this strip oscillates, the leaden ball, x, drops into the tube, c, and, on reaching the bottom of this, acts by its shock upon a cord, i, which actuates the pendulum of a clock that has previously been stopped at . the other strip, b, is very similar to the one just described, but, instead of carrying a ball, it holds a small metallic cylinder, u, so balanced that a vertical shock in an upward direction causes it to drop forward into the anterior half of the tube to the left. a second vertical shock in a downward direction causes it to drop into the other half. the cylinder, u, and the ball, x, are regulated in their positions by means of screws affixed to a stationary support. the portion of the apparatus designed to register horizontal (undulatory) motions consists of four vertical pendulums, z z z z, each of which is capable of moving in but one direction, since, in the other, it rests against a fixed column. telluric waves, according to modern observations, almost invariably in every region follow two directions that cross each other at right angles. when the seismograph has been arranged according to such directions, no matter from what part the first horizontal shock comes, one of the four pendulums will be set in motion. if, after the first undulation in one direction, another occurs in the opposite, the pendulum facing the first will in its turn begin to move; and if other undulations make themselves felt in diametrically opposite directions, the other pendulums will begin to act. these pendulums, in their motion, carry along the appendages, e e e e, which are so arranged as to fall in the center of the marble or iron table, one upon another, and thus show the order according to which the telluric waves manifested themselves. the part of the apparatus that records vertical shocks has a winch, r, which falls at the same place when the lead ball drops. the apparatus as a whole may be inclosed in a case. when it is desired to employ it, it should be mounted in a cellar, while the clock that is connected with it can be located in one of the upper stories of the house.--_f. cordenons, in la nature_. * * * * * notes on three new chinese fixed oils.[ ] [footnote : read at an evening meeting of the pharmaceutical society of great britain, feb, , .] by robert h. davies, f.i.c., f.c.s., general superintendent of apothecaries' hall. the three oils that form the subject of the examination detailed in this paper were consigned to a london broker, with a view to their being regularly exported from china if a market could be found for them here: it was, therefore, necessary to ascertain what commercial oils they resembled in character, so as to estimate to what uses they might be applied. tea oil (_camellia oleifera_). in color, transparency, and mobility, this oil considerably resembles olive oil. the odor and taste, though characteristic, are not easy to describe. ( .) _specific gravity._--the specific gravity at ° f. is . ), water at ° f. being taken as , . ( .) _action of cold._--on subjecting to the cold produced by a mixture of pounded ice and salt, some solid fatty matter, probably stearine, separates, adhering to the side of the tube. it takes a longer exposure and a lower temperature than is necessary with olive oil. i did not succeed in solidifying it, but only in causing some deposit. olive oil became solid, while almond and castor oil on the other hand did not deposit at all under similar circumstances. the lowest temperature observed was - . ° c. ( ° f.), the thermometer bulb being immersed in the oil. a few qualitative tests, viz., the action of sulphuric acid, nitric acid (sp. gr. . ), and digestion, with more dilute nitric acid ( . sp. gr.) and a globule of mercury, were first tried. when one drop of sulphuric acid is added to eight or ten drops of tea oil on a white plate, the change of color observed is more like that when almond oil is similarly treated than with any other oil, olive oil coming next in order of similarity. when a few drops of tea oil are boiled with thirty drops or so of nitric acid in a small tube, the layer of oily matter, when the brisk action has moderated, is of a light yellow color, similar in tint to that produced from almond and olive oil under similar circumstances. when the oil is digested with an equal volume of nitric acid ( . sp. gr.), and a globule of mercury added, the whole becomes converted into a mass of elaidin in about two hours, of the same tint as that produced from almond oil when similarly treated. these tests point to the fact that the oil may be considered as resembling almond or olive oil in composition, a conclusion which is borne out by the subsequent experiments. ( .) _free acidity of oil._--the oil was found to contain free acid in small quantity, which was estimated by agitating a weighed quantity with alcohol, in which the free acid dissolves while the neutral fat does not, and titrating the alcoholic liquid with decinormal alkali, using solution of phenol-phthalein as an indicator. it was thus found that grammes of the oil require . gramme of caustic potash to neutralize the free acid. mr. w. h. deering (_journ. soc. of chem. industry_, nov., ) states that in seven samples of olive oil examined by him, the minimum number for acidity was . per cent., and the maximum . per cent., the mean being . per cent. tea oil compares favorably with olive oil, therefore, in respect of acidity, a quality of which note has to be taken when considering the employment of oil as a lubricating agent. ( .) _saponification of the oil._--considerable light is thrown on the composition of a fixed oil by ascertaining how much alkali is required to saponify it. in order to estimate this, a known excess of alcoholic solution of potash is added to a weighed quantity of the oil, contained in a stout, well-closed bottle (an india-rubber stopper is the most convenient), which is then heated in a water oven until the liquid is clear, no oil bubbles being visible. phenol-phthalein solution being added, the excess of potash is estimated by carefully titrating with standard hydrochloric acid solution. it was thus found that , grammes of oil would require . grammes of caustic potash to convert it entirely into potash soap. koettstorfer, to whom this method of analysis is due, gives . , and messrs. f. w. and a. f. stoddart the numbers to , as the amounts of caustic potash required by , parts of olive oil. the numbers given by niger seed, cotton seed, and linseed oils are very similar to these. these oils differ from olive and tea oil, however, in having a higher specific gravity, and in the property they possess of drying to a greater or less extent on exposure to air. ( .) _the fatty acids produced._--a solution of the potash soap was treated with excess of hydrochloric acid, and after being well washed with hot water, the cake of fatty acids was dried thoroughly and weighed. these, insoluble in water, amounted to . per cent, of the fat taken. the proportion dissolved in the water used for washing was estimated by titration with alkali; the quantity of koh required was insignificant, equaling . per cent, of the fat originally used. this portion was not further examined. the insoluble fatty acids amounted, as last stated, to . per cent. pure olein, supposing none of the liberated acid to be dissolved in water, would yield . per cent. of fatty acid. the acid was evidently a mixture, and had no definite melting point. it was solid at ° c., and sufficiently soft to flow at ° c., but did not entirely liquefy under ° c. to test its neutralizing power, . gramme dissolved in alcohol was titrated with decinormal alkali; it required . c.c. this amount of pure oleic acid would require . c.c.; of pure stearic acid, which has almost the same molecular weight as oleic acid, . c.c.; or of pure palmitic acid, . c.c. this, taken in conjunction with the way in which the acid melted, makes it extremely probable that it is a mixture of oleic and stearic acids. additional evidence of the large proportion of oleic acid was furnished by forming the lead salt, and treating with ether, in which lead oleate is soluble, the stearate and palmitate being insoluble. in this way it was found that the oleic acid obtained from the ethereal solution of the lead salt amounted to . per cent. of the oil. this acid was proved to be oleic, by its saturating power and its melting point, which were fairly concordant with those of the pure acid. cabbage oil (_brassica, sp._). _appearance, etc._--the sample was of a deep brown color, of a fluidity intermediate between olive and castor oil, and possessed a strong, rather disagreeable odor. _the specific gravity at ° fahr._, . .--the specific gravity of rape oil and colza oil, both of which are obtained from species of the genius _brassica_, varies from . to . _exposure to cold._--this oil by exposure to a temperature of - ° c. ( ° f.) becomes solidified in course of an hour, a bright orange-yellow mass resulting. _qualitative examination._--the three reagents before indicated were applied to this oil. _(a.) sulphuric acid._--the color produced was very marked and characteristic; it differed considerably from any of the others simultaneously tested, the nearest to it being olive end rape oil. _(b.) strong nitric acid._--the reaction was more violent than before, the stratum of oil after cooling being darker in color than in the three cases before mentioned. the reaction with rape oil was similar in all respects. _(c.) elaidin test._--the solid mass of elaidin formed was of a darker color than that from olive, almond, and tea oil, but closely resembled that from rape oil. _free acidity._--this was estimated as above described. grammes of oil would require . gramme caustic potash. the samples of rape oil examined by deering (loc. cit.) were found to require from . to . koh per grammes oil. _saponification of the oil._--upon saponifying with alcoholic potash, it was found that , grammes of oil required . grammes of potash for complete saponification. the number obtained by koettstorfer for colza was . , by messrs. stoddart for rape oil, - , and by deering for rape oil, . - . . the only other oil of which i can find figures resembling these is castor oil, which requires - grammes per kilo (messrs. stoddart). the difference in specific gravity between this (cabbage) oil and castor oil and the solubility of the latter in alcohol point to a wide distinction between them. hence i think the numbers above given conclusively demonstrate the resemblance between this oil and rape oil in composition. _the fatty acids._--the acids produced by adding hcl to the potash soap were almost entirely insoluble in water. the actual amount of potash required to neutralize the acid in the wash water equaled . per cent. of the oil originally taken. the insoluble fatty acid amounted to . per cent. of the oil taken. it was evidently a mixture of two or more fatty acids. on trying to take its melting point, i found that it commenced to soften at ° c., was distinctly liquid at °, but not completely melted until ° c. according to o. bach (year book pharm., , p. ), the fatty acids from rape seed oil melt at . ° c., which is fairly concordant with the result obtained for cabbage oil acids. the neutralizing power of these acids was then tested. . gramme dissolved in alcohol required . c.c. decinormal alkali. it is a singular coincidence that brassic acid (c_{ }h_{ }o_{ }), which is a characteristic acid of colza and rape oils, would have required almost exactly this quantity of alkali for neutralization, . brassic acid theoretically saturating . c.c. of decinormal alkali. i am disposed to regard this as a coincidence, since a subsequent experiment showed that the lead salts formed were partially soluble in ether, whereas the lead salt of brassic acid is said to be insoluble in this liquid. wood oil (_elæococcus cordata_). _appearance, etc._--this oil has a decided brown color and a persistent and disagreeable odor. it is rather more fluid than castor oil. glass vessels containing it soon show a film of apparently resinous material, which forms whenever a portion of the oil flows from the lip or edge down the outside of the vessel, and is thus exposed to the air in a thin stream. this drying power is one of its most prominent characters. if a few drops be exposed in a flat dish, in the water oven, the oil dries rapidly, so that in two hours the gain in weight will be appreciable, and in four hours the whole will have become solid. _the specific gravity at ° fahr._, . .--this is an unusually high gravity for a fixed oil. the only two which exceed it are castor oil, which is , about, and croton oil, which is very similar to this, to (a. h. allen). it is interesting to note that both these oils are yielded by plants of the natural order _euphorbiaceæ_, to which the plant yielding so-called wood oil belongs. _exposure to cold._--this oil is apparently unaffected by exposure to a temperature of - . ° c. ( ° f). _qualitative examination._--the action of sulphuric acid is remarkable. when a drop comes in contact with the oil, the latter apparently solidifies round the drop of acid, forming a black envelope which grows in size and gradually absorbs and acts upon so much of the surrounding oil as to assume the appearance of a large dried currant of somewhat irregular shape. when a drop of the oil is added to nitric acid, it solidifies, and on heating very readily changes into an orange yellow solid, which appears to soften, though not to liquefy, at the temperature of boiling water. this substance is readily soluble in hot solution of potash or soda, producing a deep brown liquid, from which it is again deposited in flocks on acidifying. i have not yet found any solvent for it. the action of nitric acid with linseed oil is more similar to this than that with any other oil i have tried, but the nitro products of the two, if i may so call them, are quite different from one another. that from linseed oil produced as indicated remains liquid at ordinary temperatures, as does the oil upon its addition to the acid. _elaidin test._--by the action of nitric acid in presence of mercury, a semi-solid mass is produced of a much deeper color than in the preceding cases. a portion of the oil remains in the liquid state, as is usually the case with drying oils. _free acidity._--by the method indicated, it was found that grammes of oil required . grammes caustic potash to neutralize the acid occurring in a free state. _saponification of the oil._--the oil saponifies readily on being heated with potash in presence of alcohol, and the amount required to convert it entirely into potash soap was grammes of caustic potash per thousand grammes of oil. there are no saponification numbers for oils that can be considered close to this. i can find no record of any having been obtained between and , so that the further examination on which i am now engaged may show this unusual number to be due to this oil containing some new fatty acid in combination. _the fatty acid._--the acids produced by adding acid to the potash soap formed in this case a cake on cooling, of a much deeper color than i have before obtained. after washing well they amounted to . per cent. of the oil. the amount dissolved by the water in washing was in this case also very small, the potash required for neutralizing equaling . per cent. of the weight of oil. i found that the cakes of acids were solid at ° c., and were completely melted at °. on solution in alcohol, and digestion for two days with animal charcoal, the color was much diminished, and on the liquid being filtered and cooled to ° c., an abundance of small white crystalline plates separated out, which, when dried, melted at ° c. the crude fatty acids turn black with sulphuric acid, as the oil does, and yield a similar substance with nitric acid. it is similar in appearance, but differs in that it melts at about ° c., and is soluble in glacial acetic acid, which is not the case with the substance from the oil. these fatty acids crystallize on cooling, in a most characteristic and beautiful way, forming wavy circular plates totally unlike any that i have seen before. the above experiments may, i think, be taken as conclusive as to the nature of tea oil and cabbage oil. the former may certainly be considered a useful lubricating agent for the finer kinds of machinery. the work upon wood oil is not yet sufficiently complete to show us the nature of its proximate constituents. i am continuing the examination of this oil. perhaps i need scarcely add that there is no connection between this "wood oil" and the gurgun balsam, the product of _dipterocarpus turbinatus_, which is also known as "wood oil." * * * * * the otoscope. prof. leon le fort has recently presented to the academy of medicine, in the name of dr. rattel, a new otoscope, which we illustrate herewith. the first person to whom the idea occurred to illuminate the ear was fabricius d'acquapendentus ( ). to do this he placed the patient in front of a window in such a way as to cause the luminous rays to enter the external auditory canal. it was he likewise who conceived the idea of placing a light behind a bottle filled with water, and of projecting its concentrated rays into the ear. in fabricius de hilden invented the speculum auris. this instrument was employed by him for the first time under the following circumstances: a girl ten years of age had in playing introduced a small glass ball into her left ear, and four surgeons, called in successively and at different times, had been unable to extract it. meanwhile the little patient was suffering from an earache that extended over almost the entire head, and that increased at night and especially in cold and damp weather. to these symptoms were added strokes of epilepsy and an atrophy of the left arm. finally, in november, , de hilden, being called in, acquainted himself with the cause of the trouble, and decided to remove the foreign body. to do this, he selected, as he tells us, "a well lighted place, caused the solar light to enter the ailing ear, lubricated the sides of the auditory canal with oil of almonds, and introduced his apparatus." then, passing a scoop with some violence between the side of the auditory canal and the glass ball, he succeeded in extracting the latter. at the beginning of the th century, then, physicians had at their disposal all that was necessary for making an examination of the ear, viz.: ( ) a luminous source; ( ) a means of concentrating the light; and ( ) an instrument which, entering the auditory canal, held its sides apart. the improvements which succeeded were connected with each of these three points. to solar light, an artificial one has been preferred. d'acquapendentus' bottle has given way to the convex lens, and to concave, spherical, and parabolic mirrors, etc. de hilden's speculum has been replaced by cylindrical, conical, bivalve, and other forms of the instrument. the apparatus that we illustrate herewith offers some arrangements that are all its own as regards the process of concentrating the light. it is lighted, in fact, by a small incandescent lamp of candle-power, placed within the apparatus and supplied by an accumulator. the reflector is represented by a portion of an ellipse so calculated that one of the foci corresponds to the lamp and the other to the extremity of the instrument. a commutator, b, permits of establishing or interrupting the current at will. a rheostat added to the accumulator makes it possible to graduate the light at one's leisure and cause it to pass through all the shades comprised between cherry-red and incandescence. finally, the orifice through which the observer looks is of such dimensions that it gives passage to all the instruments necessary for treating complaints of the middle and internal ear. [illustration: rattel's otoscope.] this mode of lighting and reflection may be adapted to a brunton otoscope, utilized for examining other natural cavities, such as the nose, pharynx, etc. elliptical reflectors do not appear to have been employed up to the present. * * * * * state provision for the insane.[ ] [footnote : remarks following "definition of insanity," published in the october number of _the alienist and neurologist_, and read before the association of charities and corrections at st. louis, oct. , .] by c. h. hughes, m.d. we live in an age when every uttered sentiment of charity toward the insane is applauded to its remotest echo; an age in which the chains and locks and bars and dismal dungeon cells and flagellations and manifold tortures of the less humane and less enlightened past are justly abhorrent; an age which measures its magnificent philanthropy by munificent millions, bestowed without stint upon monumental mansions for the indwelling of the most pitiable and afflicted of the children of men, safe from the pitiless storms of adverse environment without which are so harshly violent to the morbidly sensitive and unstable insane mind; an age in which he who strikes a needless shackle from human form or heart, or removes a cause of human torture, psychical or physical, is regarded as a greater moral hero than he who, by storm or strategy of war taketh a resisting fortress; an age when the chiarugis and pinels, the yorks and tukes, of not remotely past history, and the florence nightingales and dorothea dixes of our own time, are enshrined in the hearts of a philanthropic world with greater than monumental memory. noble, christlike sentiment of human charity! let it be cherished and fostered still, toward the least of the children of affliction and misfortune, as man in his immortal aspirations moves nearer and nearer to the loving, charitable heart of god, imaging in his work the example of the divinely incarnate master! but let us always couple this exalted sentimentality with the stern logic of fact, and never misdirect or misapply it in any of our charitable work. imperfect knowledge perverts the noblest sentiments; widened and perfected knowledge strengthens their power. a truly philanthropic sentiment is most potent for good in the power of knowledge, and may be made most powerful for evil through misconception of or inadequate comprehension of facts. as we grow in aspirations after the highest welfare of the insane, let us _widen our knowledge of the real nature of insanity and the necessities for its amelioration, prevention, and cure_. it is a long time since grotius wrote, "the study of the human mind is the noblest branch of medicine;" and we realize to-day that it is the noblest study of man, regardless of vocation. aye! it is the imperative study of our generation and of those who are to follow us, if we would continue, as we wish to be, the conservators of the good and great, and promoters of advancing capability for great and good deeds in our humanity. one known and acknowledged insane person to every five hundred sane persons, and among those are unreckoned numbers of unstably endowed and too mildly mannered lunatics to require public restraint, but none the less dangerous to the perpetuation of the mental stability of the race, is an appalling picture of fact for philanthropic conservators of the race to contemplate. the insane temperament and its pathological twin brother, the neuropathic diathesis, roams at large unrestrained from without or that self-restraint which, bred of adequate self-knowledge, might come from within, and contaminates with neurotic and mental instability the innocent unborn, furnishing histogenic factors which the future will formulate in minds dethroned to become helpless wards of the state or family. the insane temperament is more enduringly fatal to the welfare of humanity than the deadly _comma bacillus_ which is supposed to convey the scourge of asia to our shores. the latter comes at stated periods, and disappears after a season or two of devastation, in which the least fit to survive of our population, by reason of feeble organic resisting power, are destroyed; while resisting tolerance is established in the remainder. but _this_ scourge is with us always, transmitting weakness unto coming generations. it is the insanity in chronic form which escapes asylum care and custody except in its exacerbations; it is the insanity of organism which gives so much of the erratic and unstable to society, in its manifestations of mind and morals; it is the form of unstable mental organism which, like an unstrung instrument jangling out of tune and harsh, when touched in a manner to elicit in men of stable organisms only concord of sweet, harmonious sounds; it is the form of mental organism out of which, by slight exciting causes largely imaginary, the guiteaus and joan d'arcs of history are made, the hawisons and passanantis and freemans, and names innumerable, whose deeds of blood have stained the pages of history, and whose doings in our day contribute so largely to the awful calendar of crime which blackens and spreads with gore the pages of our public press. we may cherish the sentiment that it were base cowardice to lay hand upon the lunatic save in kindness; and yet restrain him from himself and the community from him. we may couple his restraints with the largest liberty compatible with his welfare and ours; we may not always abolish the bolts and bars, indeed we cannot, either to his absolute personal liberty in asylums or to his entire moral freedom without their walls, yet we may keep them largely out of sight. let him be _manacled when he must and only when he must_, and then only with silken cords bound by affectionate hands, and not by chains. we may not open all the doors, indeed we cannot, but we can and do, thanks to the humanitarian spirit of the age in which we live, open many of them and so shut them, when it must need be done, that they close for _his_ welfare and ours only; that he may not feel that hope is gone or humanity barred out with the shutting of the door that separates him from the world. we may not always swing the door of the lunatic as facilely outward as inward--the nature of his malady will not always admit of this--but we should do it whenever we can, and never, when we must, should we close it harshly. and while we must needs narrow his liberty among ourselves, we should enlarge it in the community to which his affliction assigns him, to the fullest extent permissible by the nature of his malady. liberty need not necessarily be denied him; and to the glory of our age it is not in the majority of american asylums for the insane, because the conditions under which he may safely enjoy liberty, to his own and the community's welfare, are changed by disease. the free sunlight and the fresh air belong as much to him in his changed mental estate as to you or me, and more, because his affliction needs their invigorating power, and the man who would chain, in this enlightened age, an insane man in a dungeon, because he is diseased and troublesome or dangerous, would be unworthy the name of human. effective restraint may be employed without the use of either iron manacles or dismal light and air excluding dungeons. the insane man is one of our comrades who has fallen mentally maimed in the battle of life. it may be our turn next to follow him to the rear; but because we must carry him from the battlefield, where he may have fought even more valiantly than ourselves, we need not forget or neglect him. the duty is all the more imperative that we care for him, and in such a manner that he may, if possible, be restored. simple sequestration of the insane man is an outrage upon him and upon our humanity. "whatsoever ye would that men should do unto you, do ye even so to them," is the divine precept, which, if we follow it as we ought, will lead us to search for our fallen comrades in the alms-houses and penal institutions and reformatories, and sometimes in the outhouses or cellars of private homes, to our shame, where errors of judgment or cruelty have placed them, and to transfer them to places of larger liberty and hopes of happiness and recovery. the chronic insane are entitled to our care, not to our neglect, and to all the comforts they earned while battling with us, when in their best mental estate, for their common welfare and ours. almshouses and neglected outhouses are not proper places for them. they are entitled to our protection and to be so cared for, if we cannot cure them, as that they may not do those things, to their own harm or the harm of the race, which they would not do if they were sound in mind. society must be protected against the spread of hereditary insanity, hence such kindly surveillance, coupled with the largest possible liberty, should be exercised over them as will save posterity, so far as practicable, from the entailment of a heritage more fatal than cancer or consumption. the insane man is a changed man, and his life is more or less delusional. in view of this fact, we should endeavor always to so surround him that his environments may not augment the morbid change in him and intensify his perverted, delusioned character. realizing the fact that mind in insanity is rather perverted than lost, we should so deport ourselves toward the victims of this disease as in no wise to intensify or augment the malady, but always, if possible, so as to ameliorate or remove it. realizing that the insane man in his best estate may have walked the earth a king, and in this free country of ours have been an honored sovereign weighted with the welfare of his people, and contributing of his substance toward our charities, we should, with unstinting hand, cater to his comfort when this affliction comes upon him. we should give him a home worthy of our own sovereign selves, and such as would suit us were we providing for ourselves, with the knowledge we have of the needs of this affliction, pending its approach to us. that his home should be as unirritating and restful to him as possible it should be unprison-like always, and only be an imprisonment when the violent phases of his malady imperatively demand restraint. an hour of maniacal excitement does not justify a month of chains. mechanical restraint is a remedy of easy resort, but the fettered man frets away strength essential to his recovery. outside of asylums direct restraint is often a stern necessity. it is sometimes so in them, but in many of them and outside of all of them it may be greatly diminished, and asylums may be so constructed as to make the reduction of direct restraint practicable to the smallest minimum. direct mechanical restraint for the insane, save to avert an act of violence not otherwise preventable, is never justifiable. the hand should never be manacled if the head can be so influenced as to stay it, and we should try to stay the hand through steadying the head. every place for these unfortunates should provide for them ample room and congenial employment, whether profitable to the state or not, and the labor should be induced, not enforced, and always timed and suited to their malady. a variety of interesting occupations tends to divert from delusional introspection. most institutions attempt to give their patients some occupation, but state policy should be liberal in this direction. deductions are obvious: every insane community of mixed recent and long standing cases, or of chronic cases exclusively, should be a home, and not a mere place of detention. it should be as unprison-like and attractive as any residence for the non-criminal. it should have for any considerable number of insane persons at least a section ( acres) of ground. it should be in the country, of course, but accessible to the supplies of a large city. it should have a central main building, as architecturally beautiful and substantial as the state may choose to make it, provided with places of security for such as require them in times of excitement, with a chapel, amusement hall, and hospital in easy covered reach of the feeble and decrepit, and accessible, without risk to health, in bad weather. outhouses should be built with rooms attached, and set apart from the residence of trustworthy patients, for farmer, gardener, dairyman, herdsman, shepherd, and engineer, that those who desired to be employed with them, and might safely be intrusted, and were physically able, could have opportunity of work. cottages should be scattered about the ground for the use and benefit of such as might enjoy a segregate life, which could be used for isolation in case of epidemic visitation. recreation, games, drives, and walks should be liberally provided. a perfect, but not direct and offensive, surveillance should be exercised over all the patients, with a view to securing them the largest possible liberty compatible with the singular nature of their malady. in short, the hospital home for the chronic insane, or when acute and chronic insane are domiciled together, should be a colonial home, with the living arrangements as nearly those which would be most congenial to a large body of sane people as the condition of the insane, changed by disease, will allow. it is as obvious as that experience demonstrates it, that the reigning head or heads of such a community should be medical, and not that medical mediocrity either which covets and accepts political preferment without medical qualifications. the largest personal liberty to the chronic insane may be best secured to them by provision for the sexes in widely separated establishments. it is plain that the whole duty of man is not discharged toward his fallen insane brother when he has accomplished his sequestration from society at large, or fed and housed him well. the study of the needs of the insane and of the duty of the state in regard to them is as important and imperative a study as any subject of political economy. * * * * * the courage of originality. most of us are at times conscious of hearing from the lips of another, or reading from the printed page, thoughts that have existed previously in our own minds. they may have been vague and unarranged, but still they were our own, and we recognize them as old friends, though dressed in a more fitting and expressive costume than we ever gave them. sometimes an invention or a discovery dawns upon the world to bless and improve it, and while all are engaged in extolling it some persons feel that they have had its germs floating in their minds, though from the lack of favorable conditions, or some other cause, they never took root or became vital. an act of heroism is performed, and a bystander is conscious that he has that within him by which he could have taken the same step, although he did not. some one steps forward and practically opposes a social custom that is admitted to be evil, yet maintained, and by his influence lays the ax to its root and commences its destruction; while many, commending his courage, wonder why they had not taken the same course long ago. in numberless instances we are conscious of having had the same perceptions, the same ideas, the same powers, and the same desires to put them into practice that are shown by the one who has so successfully expressed them; yet they have, for some reason, lain dormant and inoperative within us. when we consider the waste of human power that this involves, we may well search for its cause. doubtless it sometimes results from the absorption (more or less needful) of each one is his individual pursuit. no one can give voice to all he thinks, or accomplish all that he sees to be desirable, while striving, as he should, to gain excellence in his own chosen work. conscious of his own limitations, he will rejoice to see many of his vague ideas, hopes, and aspirations reached and carried out by others. but the same consciousness that reconciles him to this also reveals much that he _might_ have said or done without violating any other obligation, but which he has allowed to slip from his hands to those of another, perhaps through lack of energy, or indolence, or procrastination. the cause, however, most operative in this direction is a strange disloyalty to our own convictions. we look to others, especially to what we call great men, for thoughts, suggestions, and opinions, and gladly adopt them on their authority. but our own thoughts we ignore or treat with indifference. we admire and honor originality in others, but we value it not in ourselves. on the contrary, we are satisfied to make poor imitations of those we revere, missing the only resemblance that is worth anything, that of a simple and sincere independent life. we would not undervalue modesty or recommend self-sufficiency. we should always be learners, gladly welcoming every help, and respecting every personality. but we should also respect our own, and bear in mind, that "though the wide universe is full of good, no kernel of nourishing corn can come to us but through our toil bestowed on that plot of ground which is given to us to till." to undervalue our own thought because it is ours, to depreciate our own powers or faculties because some one else's are more vigorous, to shrink from doing what we can because we think we can do so little, is to hinder our own development and the progress of the world. for it is only by exercise that any faculty is strengthened, and only by each one putting his shoulder to the wheel that the world moves and humanity advances. there is nothing more insidious than the spirit of conformity, and nothing more quickly paralyzes the best parts of a man. a gleam of truth illuminates his mind, and forthwith he proceeds to compare it with the prevailing tone of his community or his set. if it agree not with that, he distrusts and perhaps disowns it; it is left to perish, and he to that extent perishes with it. by and by, when some one more independent, more truth-loving, more courageous than himself arises to proclaim and urge the same thing that he was half ashamed to acknowledge, he will regret his inglorious fear of being in the minority. we are accustomed to think that greatness always denotes exceptional powers, yet most of the world's great men have rather been distinguished by an invincible determination to work out the best that was within them. they have acted, spoken, or thought according to their own natures and judgment, without any wavering hesitation as to the probable verdict of the world. they were loyal to the truth that was in them, and had faith in its ultimate triumph; they had a mission to fulfill, and it did not occur to them to pause or to falter. how many more great men should we have were this spirit universal, and how much greater would each one of us be if, in a simple straightforward manner, we frankly said and did the best that we knew, without fear or favor? soon would be found gifts that none had dreamed of, powers that none had imagined, and heroism that was thought impossible. as emerson well says, "he who knows that power is inborn, that he is weak because he has looked for good out of him and elsewhere, and so perceiving throws himself unhesitatingly on his thought, instantly rights himself, stands in the erect position, commands his limbs, works miracles, just as a man who stands on his feet is stronger than a man who stands on his head."--_phil. ledger._ * * * * * a circular bowling alley. the arcades under the elevated railroad which runs transversely through berlin are used as storehouses, stores, saloons, restaurants, etc., and are a source of considerable income to the railway company. the owner of one of the restaurants in the arcades decided to provide his place with a bowling alley, but found that he could not command the requisite length, ft., and so he had to arrange it in some other way. a civil engineer named kiebitz constructed a circular bowling alley for him, which is shown in the annexed cut taken from the _illustrirte zeitung_. the alley is built in the shape of a horse-shoe, and the bottom or bed on which the balls roll is hollowed out on a curved line, the outer edge of the bed being raised to prevent the balls from being thrown off the alley by centrifugal force. [illustration: a circular bowling alley.] the balls are rolled from one end of the alley, describe a curved line, and then strike the pins placed at the opposite end of the alley. no return track for the balls is required, and all that is necessary is to roll the balls from one end of the alley to the other. a recording slate, the tables for the guests, etc., are arranged between the two shanks or legs of the alley. it is evident that a person cannot play as accurately on an alley of this kind as on a straight alley; but if a ball is thrown with more or less force, it will roll along the inner or outer edge of the alley and strike the group of pins a greater or less distance from the middle. a room ft. in length is of sufficient size for one of these alleys. * * * * * patent office examination of inventions. _to the editor of the scientific american:_ it is with considerable surprise that the writer has just perused the editorial article in your issue of march the th--"patent office examinations of novelty of inventions" it seems to me that the ground taken therein is diametrically opposed to the views heretofore promulgated in your journal on this subject, and no less so to the interests of american inventors; and it appears difficult to understand why the abolition of examinations for novelty by the patent office should be recommended in face of the fact that the acknowledged small fees now exacted from inventors are sufficient to provide a much greater force of examiners than are now employed on that work. if inventors were asking the government to appropriate money for this purpose, the case would be quite different; although it may be shown, i think, that congress would be fully justified in disposing of no inconsiderable portion of the public money in this way, should it ever become necessary. recognizing the fact that the patent records of all countries, as well as cognate publications, are rapidly on the increase--and particularly in this country--making an examination for novelty a continuously increasing task, and that the time must come when such an examination cannot be made at all conclusively without a vastly increased amount of labor, from the very magnitude of the operation, it is nevertheless true that this difficulty menaces the inventor to a much greater extent, if imposed upon him to make, than it can ever possibly do an institution like the patent office. dividing and subdividing patent subjects into classes and sub-classes, and systematizing examinations to the extent it may be made to reach in the patent office, may, for a very long time to come, place this matter within the possibility of a reasonably good and conclusive search being made without additional cost to the inventor, provided what he now pays is all devoted to the furtherance of the patent office business. if, however, we hereafter make no examinations for novelty, an inventor is obliged to either make such a search for himself--with all the disadvantages of unfamiliarity with the best methods, inaccessibility to records, and incurring immensely more work than is required of the patent office examiner, who has everything pertaining thereto at his fingers' ends--or blindly pay his fees and take his patent under the impression that he is the first inventor, and run every risk of being beaten in the courts should any one essay to contest his claims; the probabilities of his being so beaten increasing in proportion as the number of inventions increase. the inventor pays to have this work done for him at the patent office in the only feasible way it can be thoroughly done; and the average inventor would, or should, be willing to have the present fees very largely increased, if necessary, rather than have the examinations for novelty abolished at the patent office; for, in the event of their abolition, it would cost him immensely more money to secure himself, as before the courts, by his own unaided and best attainable methods. the inventor now, however, pays to the patent office, as you well know, a good deal more money every year than the present cost of examinations, including of course all other patent office business; seeing a part of what he pays yearly covered into the treasury as surplus, while his application is unreasonably delayed for the lack of examiner force in the patent office. let the government first apply all the moneys received at the patent office to its legitimate purpose, including the making of these examinations, and, when this proves insufficient, you may depend that every inventor will cheerfully consent to the increase of fees, sufficient to insure the continuance of thorough examinations for novelty, rather than attempt to do this work himself or take the chances of his having reinvented some old device (which it is very well known occurs over and over again every day), and being beaten upon the very first contest in the courts, after, perhaps, investing large amounts of money, time, and anxiety over something which he thus discovers was invented, perhaps, before he was born. for an inventor to obtain a patent worth having, and one that is not more likely to be a source of expenditure than income to him, if contested, it goes without saying that examination for novelty must be made either by himself or some competent person or persons for him; and it is strictly proper and just that the inventor should pay for it; and it is too self-evident a proposition to admit of argument that the organized and systematized methods of the patent office can do it at a tithe of the expense which would be incurred in doing it in any other way; in point of fact, it would be impossible to do it by any other means so effectually or so well within any reasonable amount of cost. your summing up of the case should, instead of the way you put it, read: the commissioner of patents attempts to perform for two-thirds the sum paid as fees by inventors what he is paid three-thirds to accomplish, so that one-third of it may go to swell the surplus of the united states treasury, and finds it an impracticable task to ascertain the novelty of an invention in a reasonable time for such a sum. to perform it, however imperfectly, he feels authorized to delay the granting; of patents, sometimes for several months, simply because congress will not allow him to apply the moneys paid by inventors to their legitimate purpose. i have had, for several years, always more or less applications on file at the patent office for inventions in my particular line, and now have several pending; and probably there are few, if any, who have suffered more from the great delays lately obtaining at that institution than myself, particularly in connection with taking out foreign patents for the same inventions, and so timing the issue of them here and abroad as not to prejudice either one. but great as the annoyance and cost have been in consequence of these delays, i would infinitely prefer that it were ten times as great, rather than see the examinations for novelty abolished by the united states patent office; and, so far as i know and believe, in this preference i most completely voice that of inventors in general. john t. hawkins. taunton, mass., march th, . the writer of the above communication gives a very clear statement of our original premises. he sees as we do the difficulty, every year on the increase, of making satisfactory searches in the matter of novelty. but his deductions vary from ours. to us it appears on its face an impossibility for satisfactory searches to be made in the case of every individual patent by the patent office. the examinations have repeatedly been proved valueless. we know by our own and others' experience that the searches as at present conducted are of comparatively little accuracy. patents are declared to be anticipated continually by our courts. the awarding of a patent in fact weighs for nothing in a judge's mind as proving its originality. the commissioner of patents is really exhausting the energies of the office employees over a multitude of searches that have no standing whatever in court, and that no lawyer would accept as any guarantee of novelty of invention. if every inventor would search the records for his own benefit, we should then have twenty thousand examiners instead of the present small number. this would be something. but if it be advanced that the inventor is not a competent searcher, then he can engage an expert to do it for him. every day, searches of equal value to the patent office ones are executed for but a fraction of the government fees on granting a patent. our correspondent speaks of an evil that he thinks would be incidental to the system we proposed in our article criticised by him, namely, that were the patent office to make no search an inventor would "run every risk of being beaten in the courts should any one essay to contest his claims." the fact is that in spite of the office examination for novelty this risk always has to be encountered, and forms a criterion by which to judge of the exact value of that examination. furthermore, we take decided issue with our correspondent when he says that the present is the only feasible way of executing these searches thoroughly. they are not so executed as a matter of fact, and could be done better and cheaper by private individuals, experts, or lawyers, engaged for the purpose by inventors. we agree that all money received by the patent office should be applied to its legitimate end. it seems to us a great injustice to make one generation of patentees accumulate money in the treasury for the benefit of some coming generation. application of the whole of each year's fees to the expediting of that year's business would be simple justice. but we do not lose sight of our main point, that were the inventor unable to make a satisfactory search, it could be done for him by private parties better and cheaper than it is now done in the office. we are very glad to have the question so intelligently discussed as by our correspondent, and we feel that it is one well worthy of consideration. the future will, we are sure, bring about some change, by which inventors will be induced to bestow more personal care on their patents, at least to the extent of securing searches for novelty to be made by their own attorneys, and even at a little additional expense to abandon any blind dependence on the patent office as a prover of novelty.--ed. sc. am. * * * * * the universal exposition at antwerp (anvers), belgium. never before was there so striking and remarkable an example of what can be accomplished by private enterprise when applied to a great and useful object. last year some prominent citizens of antwerp--justly proud of the rapid and marvelous progress made by their city--conceived the idea of inviting the civilized world to come and admire the transformation which, in half a century, had converted the commercial metropolis of belgium into the first port of the european continent. this audacious project has been carried into execution, and the buildings of the universal exposition, including the hall of industry, the gallery of machinery, and the innumerable annexes, cover , , sq. ft. of ground. even this large space has proved too limited. these buildings are shown in the accompanying cut. all nations have responded to the call of the citizens of antwerp, who are supported by the patronage of a sovereign devoted to progress, leopold ii., king of the belgians. among the countries represented in the exposition, france takes the first rank. she is represented by over , exhibits, and her products occupy one-fifth part of the hall of industry and the gallery of machinery. the pavilion of the french colonies is an exact representation of a palace of cochin china. belgium is represented by , exhibits. the french and belgian compartments together occupy one-half of the hall of industry and the gallery of machinery. this latter building represents a grand spectacle, especially in the evening, when it is lighted by electricity. in excavating under this gallery, ruins were brought to light which proved to be the foundations of the citadel of the duke d'albe, the terrible lieutenant of philip ii. of spain. thus, on the same site where once stood this monument of oppression and torture, electricity, that bright star of modern times, will illuminate the most wonderful inventions of human progress.--_l'illustration._ [illustration: bird's-eye view of the universal exposition at d'anvers, belgium.] * * * * * the stone pine. (pinus pinea.) although not such an important tree in this country as many other conifers, the stone pine possesses a peculiar interest beyond that of any other european conifer. from the earliest periods it has been the theme of classical writers. ovid and pliny describe it; virgil alludes to it as a most beautiful ornament; and horace mentions a pine agreeing in character with the stone pine; while in pompeii and herculaneum we find figures of pine cones in drawings and on the arabesques; and even kernels of charred pines have been discovered. the pinaster of the ancients does not appear to be the same as that of the moderns; the former was said to be of extraordinary height, while the latter is almost as low as the stone pine. no forest is fraught with more poetical and classical interest than the pine wood of ravenna, the glories of which have been especially sung by dante, boccacio, dryden and byron, and it is still known as the "vicolo de' poeti." the stone pine is found in a wild state on the sandy coasts and hills of tuscany, to the west of the apennines, and on the hills of genoa, usually accompanied by, and frequently forming forests with, the pinus pinaster. it is generally cultivated throughout the whole of italy, from the foot of the alps to sicily. it is not commonly found higher than from , feet to , feet, but it occurs in the south of italy as high as , feet. it is found, according to sibthorp, on the sandy coasts of the western peloponnesus, in the same conditions, probably, as in the middle of italy; it is also met with in the island of melida. cultivated, it is found on all the shores of the mediterranean. in northern europe, and especially in england, its general appearance is certainly that of a low-growing tree, its densely clothed branches forming almost a spherical mass; but in the sunny south it attains a height of feet to feet, losing, as it ascends, all its branches, except those toward the summit, which, in maturity, assume a mushroom form. seen in the soft clime of italy in all its native vigor, the stone pine is always majestic and strangely impressive to a northern eye, whether in dense forests, as near florence, in more open masses, as at ravenna, in picturesque groups, as about rome, or in occasional single trees, such as may be seen throughout the country, but rather more frequently toward the coast. in these isolated trees their imposing character can be best appreciated, the great trunk carrying the massive head perfectly poised, an interesting example of ponderous weight gracefully balanced. the solid, weighty appearance of the head of the tree is increased by its even and generally symmetrical outline, this especially in the examples near the coast, the mass of foliage being so close and dense that it looks like velvet, and in color a warm rich olive green, strangely different from the blue greens and black greens of our northern pines. the lofty or normal type with the umbrella-formed top is almost peculiar to central and southern italy. in other parts of the south of europe, though often attaining large dimensions, it remains more dwarf and rotund in shape. [illustration: the stone pine (pinus pinea) at castel gandolfo, in italy.] this pine has not been much planted in this country, owing, no doubt, to its slow growth and want of hardiness in a young state. consequently there are not many large specimens, and certainly none to compare with those of italy for size or picturesque beauty. mr. a. d. webster, the forester at penrhyn castle, north wales, who has kindly sent us a fine cone of this pine, writes thus respecting it: "a fair-sized specimen of this pine stands on the sloping ground to the southwest of penrhyn castle. it shows off to advantage the peculiar outline of this pine, which is so marked a characteristic of those grown in the mediterranean region. the trunk, which is about ½ feet in girth at a yard up, rises for three-fourths its height without branches, after which it divides into a number of limbs, the extremities of which are well covered with foliage, thus giving to the tree a bushy, well-formed, and, i might almost add, rounded appearance. at a casual glance the whole tree might readily be mistaken for the pinaster, but the leaves are shorter, less tufted, and always more erect. the bark of the stone pine is somewhat rough and uneven, of a dull gray color, unless between the furrows, which is of a bright brown. that on the branches is more smooth and of a light reddish brown color. when closely examined, there is something remarkably pleasing and distinct from the generality of pines in the appearance of this tree, the leaves, which are of a deep olive-green, being, from their regularity and usual closeness, when seen in good light, like the finest network." there is a moderately large specimen in the arboretum at kew, and if this is the tree which loudon in his "arboretum" alluded to as a "mere bush," it has made good growth during the past thirty years. according to veitch's "manual of coniferæ," a fine specimen, one of the largest in the country, is at glenthorn, in north devon. it is feet high, and has a spread of branches some feet, while the trunk is clear of branches for feet. loudon enumerates several fine trees in these islands at that date ( ), only one of which was feet high. this one was at ballyleady, in county down, and had been planted about years. even where planted in the most favored localities, we can never expect the stone pine to assume its true character, and that is the reason why so few plant it. as a timber tree it is of not much value. mr. webster says, "the wood is worthless except for very ordinary purposes. the timber grown here (penrhyn) is, from the few specimens i have had the chance of examining, very clean, light, from the small quantity of resin it contains, and in color very nearly approaches the yellow pine of commerce. it cuts clean and works well under the tools of the carpenter. in its native country the wood has been used for boat-building, but is now, i believe, almost entirely discarded." this pine thrives best on a soil that is deep, sandy, and dry. it should be well sheltered and nursed, as it is rather tender while in its young state. it is best to keep the seedlings under glass, though they may be planted out in the open air after their fourth or fifth year. the cones of this pine supply the "pignoli" of commerce. the italian cooks use these seeds in their soups and ragouts, and in the maritozzi buns of rome. sometimes the italians roast the barely ripe cone, dashing it on the ground to break it open, but the ripe seeds of the older cone when it naturally opens are better worth eating. they are soft and rich, and have a slightly resinous flavor. the empty cones are used by the italians for fire lighting, and being full of resinous matter they burn rapidly and emit a delightful fragrance. _description._--pinus pinea belongs to the pinaster section of the genus. in the south of europe it is a lofty tree, with a spreading head forming a kind of parasol, and a trunk feet or feet high, clear of branches. the bark of the trunk is reddish and sometimes cracked, but the general surface of the bark is smooth except on the smaller branches, where it long retains the marks of the fallen leaves, in the shape of bristly scales. the leaves are of a dull green, but not quite so dark as those of the pinaster; they are semi-cylindrical, inches or inches long and one-twelfth of an inch broad, two in a sheath, and disposed in such a manner as to form a triple spiral round the branches. the catkins of the male flowers are yellowish; and being placed on slender shoots of the current year, near the extremity, twenty or thirty together, they form bundles, surmounted by some scarcely developed leaves. each catkin is not more than half an inch long, on a very short peduncle, and with a rounded denticulated crest. the female catkins are whitish, and are situated two or three together, at the extremity of the strongest and most vigorous shoots. each female catkin has a separate peduncle, charged with reddish, scarious, lanceolate scales, and is surrounded at its base with a double row of the same scales, which served to envelop it before it expanded; its form is perfectly oval, and its total length about half an inch. the scales which form the female catkin are of a whitish green; the bractea on the back is slightly reddish on its upper side; and the stigma, which has two points, is of a bright red. after fertilization, the scales augment in thickness; and, becoming firmly pressed against each other, they form by their aggregation a fruit, which is three years before it ripens. during the first year it is scarcely larger than the female catkin; and during the second year it becomes globular, and about the size of a walnut. the third year the cones increase rapidly in size; the scales lose their reddish tinge, and become of a beautiful green, the point alone remaining red; and at last, about the end of the third year, they attain maturity. at this period the cones are about four inches long and three inches in diameter, and they have assumed a general reddish hue. the convex part of the scales forms a depressed pyramid, with rounded angles, the summit of which is umbilical. each scale is hollow at its base; and in its interior are two cavities, each containing a seed much larger than that of any other kind of european pine, but the wing of which is, on the contrary, much shorter. the woody shell which envelops the kernel is hard and difficult to break in the common kind, but in the variety fragilis it is tender, and easily broken by the fingers. in both the kernel is white, sweet, and agreeable to the taste. the taproot of the stone pine is nearly as strong as that of p. pinaster; and, like that species, the trees, when transplanted, generally lean to one side, from the head not being correctly balanced. hence, in full-grown trees of the stone pine there is often a similar curvature at the base of the trunk to that of the pinaster. the palmate form of the cotyledons of the genus pinus is particularly conspicuous in those of p. pinea. when one of the ripe kernels is split in two, the cotyledons separate, so as to represent roughly the form of a hand; and this, in some parts of france, the country people call _la main de dieu_, and believed to be a remedy in cases of intermittent fever if swallowed in uneven numbers, such as , , or . the duration of the tree is much greater than that of the pinaster, and the timber is whiter and somewhat more durable. in the climate of london trees of from fifteen to twenty years' growth produce cones. there are no well-marked varieties of the stone pine, though in its native districts geographical forms may occur. for instance, loudon describes a variety cretica, which is said to have larger cones and more slender leaves. duhamel also describes a variety fragilis, having thinner shells to the seeds or kernels. neither of these varieties is in this country, so far as we are aware. there are various synonyms for p. pinea, the chief being p. sativa of bauhin, p. aracanensis of knight, p. domestica, p. chinensis of knight, and p. tarentina of manetti.--_the garden._ * * * * * the art of breeding. from a paper read by c. m. winslow, brandon, vt., before the ayrshire breeders, at their annual meeting, in boston, feb. , : sometimes we meet with breeders whose only aim in their stock seem to be to produce animals that shall be entitled to registry. to such i have little to say, as their work is comparatively easy, and has but few hindrances to success; but to those breeders who are possessed of an ideal type of perfection, which they are striving to impress upon their stock, i have a few words to say upon the hindrances they may find in the way of satisfactory results. it is a law of nature that the offspring resembles some one or more of its ancestors, not only in the outward appearance, but in the construction of the vital organism and mental peculiarities, and is simply a reproduction, with the accidental or intentional additions that from time to time are accumulating as the stock passes through the hands of more or less skillful breeders. the aim of the breeder is to not only produce an animal which shall in its own person possess the highest type of excellence sought, but shall have the power to transmit to its offspring those qualities of value possessed by himself. a breeder may, by chance, produce a superior animal, or it may be the result of carefully laid plans and artfully controlling the forces of nature and subjecting them to his will. it is comparatively easy to accidentally produce an animal of value, but to steadily breed to one type is the test of the skill of the breeder and the value of his stock. however well he may lay his plans, or however desirable his stock may appear, his ability to perpetuate their desirable qualities will depend upon the prepotence of the animals, and this prepotence depends, to a great extent, upon the length of the line in which the stock has been bred with one definite end in view. a man may, in his efforts to breed stock excelling in a certain line, produce stock that shows excellence in other qualities, but this will not compensate for a deficiency in the qualification he is attempting to impress, nor is it safe to breed from any animal that does not show, in a marked degree, those desired qualities. there is one qualification without which there can be no success, and that is a sound, healthy constitution, with good vital organs and vigorous digestion; and any amount of success in other directions will not compensate for lack of constitution, and disappointment is always sure to attend the breeder who does not guard this, the foundation of all success.... the very finest type of breeding and surest plans of success may be entirely defeated by improper feed and care. a valuable herd may be entirely ruined by a change of food and care; for those conditions which have conspired to produce a certain type must be continued, or the type changes, it may be for the better or it may be for the worse, since stock very readily adapt themselves to their surroundings; and it is just here that so many are disappointed in buying blood stock from a successful breeder; for a successful breeder is necessarily a good feeder and a kind handler, and stock may give good results in his hands, and, if removed to starvation and harshness, quickly degenerate. so, too, stock that has been bred on poor pasturage will readily improve if transplanted to richer pastures and milder climate. therefore he who would prove himself an artist in moulding his herd at will, must not only bring together into his herd many choice lines of goodness, but must ever seek, by kind treatment and good care, to change their qualities for the better, and by right selection and careful breeding so impress these changes for the better as to make them hereditary. if this course is persistently adhered to, the stock will gradually improve, retaining the good qualities of the ancestry, and developing new ones, generation by generation, under the hand of the artist breeder. * * * * * the babylonian palace. in a recent lecture on "babylonian and assyrian antiquities," at the british museum by mr. w. st. chad boscawen, the architecture and ornaments of a typical palace were described. the palace, next to the local temple, was, the lecturer said, the most important edifice in the ancient city, and the explorations conducted by sir henry layard, mr. rassam, m. botta, and others, had resulted in the discovery of the ruins of many of the most famous of royal residences in nineveh and babylon. the palace was called in the inscriptions the "great house," as the temple was "god's house," though in later times it was also named "the abode of royalty," "the dwelling-place of kings," while the great palace of nebuchadnezzar at babylon, the ruins of which are marked by the kasr mound, was called "the wonder of the earth." the arrangement of the palace was one which varied but little in ancient and modern times, the same grouping of quadrangles, with intermural gardens, being alike common to the assyrian palace and the turkish serai. the earliest of the assyrian palaces were those built in assur, which dated probably from the nineteenth century before the christian era; but the seat of royalty was at an early period transferred from assur to calah, the site of which is marked by the great mounds of nimroud at the junction of the greater lab and the tigris. here large palaces were erected by the kings of the middle assyrian empire, the most lavish of royal builders being assur-nazir-pal and shalmanisar; while a third palace was built by tiglath pileser ii. (b. c. ). mr. boscawen described the explorations carried out by sir henry layard on this site. the most important chamber in the building was the long gallery or saloon, which had been called the "hall of assembly." the various parts of this palace included the royal apartments, the harem, and the temple, with its great seven-stage tower or observatory. the very extensive and systematic explorations carried out by the french explorer m. botta had restored the remains of one of the most beautiful of the assyrian palaces. the usurpation of the assyrian throne by sargon the tartar in b. c. placed in power a new dynasty, who were lavish patrons of the arts and who made nineveh a city of palaces. probably on account of his violent seizure of the throne, sargon was afraid to reside in any of the existing places at nineveh--though he appears for a short time to have occupied the old palace; he built for himself calah, at a short distance to the northeast of nineveh, the palace town of dun sargina, "the fort of sargon," one of the most luxurious palaces--the versailles of nineveh. the ruins of this palace were buried beneath the mound of korsabad, and were explored by m. botta on behalf of the french government, and the sculptures and inscriptions are now deposited in the louvre. compared with all the assyrian palaces, later or earlier, this royal abode of sargon stands alone. the sculptures were more magnificent, while warmth and color were obtained by the extensive use of colored bricks. some of the cornices and friezes of painted bricks, of which mr. boscawen exhibited drawings, were most rich in ornament. the chief colors employed were blue and yellow, and sometimes red and green. having described the general construction of this remarkable building, mr. boscawen proceeded to speak of the character of assyrian art during the golden age (b.c. - ), and he illustrated his remarks by the exhibition of several large drawings. one of the most elaborate of these was the embroidery on the royal robe. the pectoral was covered with scenes taken from babylonian myths. on the upper part was isdubar or nimrod struggling with the lion; below this a splendid representation of merodach, as the warrior of the gods armed for combat against the demon of evil, while the lower part was covered with representations of the worship of the sacred tree. the general character of assyrian art, its attention to detail, and the wonderful skill in representing animal life, as exhibited in the hunting scenes, was next spoken of, and mr. boscawen concluded by a brief description of the royal library, a most important part of the great palace at nineveh. * * * * * a catalogue containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. * * * * * all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. * * * * * all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . stitched in paper, or $ . bound in stiff covers. * * * * * combined rates.--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway, new york, n.y. * * * * * patents. in connection with the scientific american, messrs. munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats, trade marks, their costs, and how procured. address munn & co., broadway, new york. branch office, cor. f and th sts., washington, d. c. none [transcribers notes: a few images have been repaired where damage was obvious, such as specks on the original plate or voids in the printing process. a gamma correction of . has been applied to compensate for aging of the ink. the index has been moved from the back of the book to the front and linked to the named pages. the images shown are compressed to x to load quickly and fit on any computer screen. click on the below the picture to see the x image. click on or the image itself to see the original x image and marvel at the detail of these photographs. signs and flags are easily read. the only technical flaw is the long exposure to produce the crisp detail and depth of field. occasionally the moving leg of a pedestrian is blurred. find the man mowing the grass in plate . click "back" on your browser to return to this list. to see the full detail of the x image in your browser, turn off "resize large images to fit" or "enable automatic image resizing". files names xxx.jpg are the original dpi, xxx_ .jpg are % of the original ( dpi), and xxx_ are % ( dpi). chapter v, "the world's columbian exposition" from volume v of "history of the united states" by e. benjamin andrews ( ) is included to provide a contemporary description of the exposition. ] official views of the world's columbian exposition issued by the department of photography c. d. arnold h. d. higinbotham official photographers press chicago photo-gravure co. index. scene plate administration building , , agricultural building arabian village , , austrian exhibit band stand battle ship "illinois" belgian exhibit. bell telephone exhibit blarney castle brazilian building cafe de la marine cairo street ceylon building chocolate pavilion choral hall cliff dwellers colonnade columbian fountain , columbus' caravels , court of honor , dahomey village donegal castle. electricity building , , , , ferris wheel , fine arts palace , , fisheries building , french exhibit french government building general views , , , , . , , , , , , , , , , , german government building german exhibits , , german village , government buildings , , , , , , , , , guatemala building hagenbeck's arena hayti building horticultural building , illinois building indian pavilion indians' wigwams, etc. , japanese exhibits , , , , johore bungalow krupp building lapland village manufactures and liberal arts building , , , , , , , , , , , , , machinery hall , , merchant tailors building midway views , , , , , , , , , , , , , , , , , , , , , , , mines building , movable sidewalk new south wales building new york building norwegian exhibit old vienna , , , pennsylvania building peristyle peristyle and quadriga rabida convent russian exhibit samoan village spanish building state buildings , , , swedish building terminal station tiffany and gorham exhibits train of transportation building , , turkish building turkish village , u. s. government building u. s. life saving station venezuela building venetian boat victoria house viking ship whaleback at pier west point cadets encampment woman's building , wooded island world's congress of beauty plate --manufactures and liberal arts building. plate --northern facade of liberal arts building. plate --liberal arts building--west entrance. plate --birds eye view looking northwest from liberal arts building. plate --southwest pavilion of liberal arts building. plate --tiffany and gorham exhibits--manufactures building. plate --russian exhibit--manufactures building. plate --entrance to german exhibit--liberal arts building. plate --austrian exhibit--manufactures building. plate --french and belgian sections--manufactures building. plate --norwegian exhibit--manufactures building. plate --the peristyle. plate --peristyle and quadriga. plate --a chocolate pavilion. plate --the court of honor. plate --a view near the peristyle. plate --looking west from peristyle. plate --agricultural building. plate --general view--looking towards colonnade. plate --the colonnade. plate --the liberal arts building from colonnade. plate --palace of mechanic arts. plate --administration building. plate --the columbian fountain. plate --section of palace of mechanic arts and administration building. plate --band stand at administration building. plate --view from electricity building--looking southeast. plate --electricity building and columbian fountain. plate --electricity building. plate --interior of electricity building. plate --base of electric tower.--electricity building. plate --bell telephone exhibit--electricity building. plate --administration building from wooded island. plate --mines building--from the north. plate --venetian boat on the lagoon at north entrance of mines building. plate --the terminal station. plate --first train in state of new york, run on the mohawk & hudson r. r., . plate --looking north from terminal station. plate --transportation building. plate --a german gateway in wrought iron--transportation building. plate --the golden door, transportation building. plate --choral hall. plate --horticultural building from wooded island. plate --looking south from loggia of woman's building. plate --woman's building. plate --brazil sweden cafe de la marine fisheries looking east from woman's building. plate --the illinois building. plate --looking west from cafe de la marine. plate --view of japanese tea garden--from lagoon. plate --the japanese tea garden. plate --japanese boat on the lagoon. plate --cafe de la marine. plate --fisheries building from wooded island. plate --united states government building and japanese ho-o-den. plate --the japanese ho-o-den. plate --liberal arts building from wooded island. plate --wooded island near horticultural building. plate --merchant tailors building. plate --palace of fine arts. plate --palace of fine arts--section of south front. plate --interior of palace of fine arts. plate --feeding the ducks. plate --avenue of state buildings. plate --new york state building. plate --pennsylvania building. plate --looking west from life saving station. plate --united states life saving station. plate --encampment of west point cadets, government plaza. plate --battle ship "illinois." plate --the viking ship. plate --great britain, victoria house. plate --buildings of spanish and german governments. plate --government building, france. plate --the brazilian building. plate --government buildings, sweden, hayti and new south wales. plate --government building, venezuela. plate --turkish building. plate --guatemala building. plate --the ceylon building. plate --on the beach--east of manufactures building. plate --the indian pavilion. plate --whaleback at exposition pier. plate --the moving sidewalk on pier. plate --convent of la rabida. plate --the santa maria. plate --the nina and pinta. plate --the krupp building. plate --birchbark wigwams of penobscot indians. plate --houses and totem poles of alaskan indians. plate --the cliff dwellers. plate --the ferris wheel. plate --world's congress of beauty, on the midway. plate --blarney castle, on the midway. plate --hagenbeck's arena--on the midway. plate --donegal castle, on the midway. plate --the samoan village--on the midway. plate --the midway, looking west. plate --the midway, from ferris wheel, looking east. plate --entrance to the german village, on the midway. plate --german village--midway. plate --the johore bungalow--on the midway. plate --in the turkish bazaar. plate --a minaret in the cairo street--on the midway. plate --turkish ladies in turkish village--on the midway. plate --ferris wheel--from the west. plate --entrance to old vienna--on the midway. plate --sausage vender--old vienna. plate --old vienna--on the midway. plate --east court in old vienna. plate --dahomey village--on the midway. plate --the lapland village--on the midway. plate --types of the arabian village--on the midway. plate --scene at arabian village--on the midway. plate --in the arabian village--on the midway. plate --court of honor from administration building. end of official views of the world's columbian exposition excerpt from "history of the united states". chapter v. the world's columbian exposition [illustration: parade.] columbian celebration, new york, april , . parade passing fifth avenue hotel. the thought of celebrating by a world's fair the third centennial of columbus's immortal deed anticipated the anniversary by several years. congress organized the exposition so early as , fixing chicago as its seat. that city was commodious, central, typically american. a national commission was appointed; also an executive committee, a board of reference and control, a chicago local board, and a board of lady managers. the task of preparation was herculean. jackson park had to be changed from a dreary lakeside swamp into a lovely city, with roads, lawns, groves and flowers, canals, lagoons and bridges, a dozen palaces, and ten score other edifices. an army of workmen, also fire, police, ambulance, hospital, and miscellaneous service was organized. wednesday, october (old style, october ), , was observed as columbus day, marking the four hundredth anniversary of columbus's discovery. a reception was held in the chicago auditorium, followed by dedication of the buildings and grounds at jackson park and an award of medals to artists and architects. many cities held corresponding observances. new york chose october th for the anniversary. on april - , , again, the eastern metropolis was enlivened by grand parades honoring columbus. in the naval display, april d, thirty-five war ships and more than , men of divers flags, took part. [illustration: three small ships.] pinta, santa maria, nina, lying in the north river, new york. the caravels which crossed from spain to be present at the world's fair at chicago. between columbus day and the opening of the exposition came the presidential election of . ex-president cleveland had been nominated on the first ballot, in spite of the hill delegation sent from his home state to oppose. harrison, too, had overcome platt, hill's republican counterpart in new york, and in pennsylvania had preferred john wanamaker to quay. but harrison was not "magnetic" like blaine. with what politicians call the "boy" element of a party, he was especially weak. stalwarts complained that he was ready to profit by their services, but abandoned them under fire. the circumstances connected with the civil service that so told against cleveland four years before, now hurt harrison equally. though no doubt sincerely favoring reform, he had, like his predecessor, succumbed to the machine in more than one instance. the campaign was conducted in good humor and without personalities. owing to australian voting and to a more sensitive public opinion, the election was much purer than that of . the republicans defended mckinley protection, boasting of it as sure, among other things, to transfer the tin industry from wales to america. free sugar was also made prominent. some cleavage was now manifest between east and west upon the tariff issue. in the west "reciprocity" was the republican slogan; in the east, "protection." near the atlantic, democrats contented themselves with advocacy of "freer raw materials "; those by the mississippi denounced "republican protection" as fraud and robbery. if the platform gave color to the charge that democrats wished "british free trade," mr. cleveland's letter of acceptance was certainly conservative. populism, emphasizing state aid to industry, particularly in behalf of the agricultural class, made great gains in the election. general weaver was its presidential nominee. in colorado, idaho, kansas, and wyoming most democrats voted for him. partial fusion of the sort prevailed also in north dakota, nevada, minnesota, and oregon. weaver carried all these states save the two last named. in louisiana and alabama republicans fused with populists. the tillman movement in south carolina, nominally democratic, was akin to populism, but was complicated with the color question, and later with novel liquor legislation. it was a revolt of the ordinary whites from the traditional dominance of the aristocracy. in alabama a similar movement, led by reuben f. kolb, was defeated, as he thought, by vicious manipulation of votes in the black belt. [illustration: large building in the background, foot bridge in the foreground.] the manufactures and liberal arts building, seen from the southwest. of the total four hundred and forty-four electoral votes cleveland received two hundred and seventy-seven, a plurality of one hundred and thirty-two. the senate now held forty-four democrats, thirty-seven republicans, and four populists; the house two hundred and sixteen democrats, one hundred and twenty-five republicans, and eleven populists. early on the opening day of the exposition, may , , the chief magistrate of the nation sat beside columbus's descendant, the duke of veragua. patient multitudes were waiting for the gates of jackson park to swing. "it only remains for you, mr. president," said the director-general, concluding his address, "if in your opinion the exposition here presented is commensurate in dignity with what the world should expect of our great country, to direct that it shall be opened to the public. when you touch this magic key the ponderous machinery will start in its revolutions and the activity of the exposition will begin." after a brief response mr. cleveland laid his finger on the key. a tumult of applause mingled with the jubilant melody of handel's "hallelujah chorus." myriad wheels revolved, waters gushed and sparkled, bells pealed and artillery thundered, while flags and gonfalons fluttered forth. the exposition formed a huge quadrilateral upon the westerly shore of lake michigan, from whose waters one passed by the north inlet into the north pond, or by the south inlet into the south pond. these united with the central grand basin in the peerless court of honor. the grounds and buildings were of surpassing magnitude and splendor. interesting but simple features were the village of states, the nations' tabernacles, lying almost under the guns of the facsimile battleship illinois, and the pigmy caravels, nina, pinta, and santa maria, named and modelled after those that bore columbus to the new world. these, like their originals, had fared from spain across the atlantic, and then had come by the st, lawrence and the lakes, without portage, to their moorings at chicago. [illustration: large domed building.] horticultural building, with illinois building in the background. near the centre of the ground stood the government building, with a ready-made look out of keeping with the other architecture. critics declared it the only discordant note in the symphony, looking from the illinois building across the north pond, one saw the art palace, of pure ionic style, perfectly proportioned, restful to view, contesting with the administration building for the architectural laurels of the fair. south of the illinois building rose the woman's building, and next horticultural hall, with dome high enough to shelter the tallest palms. the manufactures and liberal arts building, of magnificent proportions, did not tyrannize over its neighbors, though thrice the size of st. peter's at rome, and able easily to have sheltered the vendome column. it was severely classical, with a long perspective of arches, broken only at the corners and in the centre by portals fit to immortalize alexander's triumphs. the artistic jewel of the exposition was the "court of honor." down the grand basin you saw the noble statue of the republic, in dazzling gold, with the peristyle beyond, a forest of columns surmounted by the columbus quadriga. on the right hand stood the agricultural building, upon whose summit the "diana" of augustus st. gaudens had alighted. to the left to the left stood the enormous hall of manufactures. looking from the peristyle the eye met the administration building, a rare exemplification of the french school, the dome resembling that of the hotel des lnvalides in paris. [illustration: many pedestrians surrounded by large classical building.] a view toward the peristyle from machinery hall. a most unique conception was the cold storage building, where a hundred tons at ice were made daily. save for the entrance, flanked by windows, and the fifth floor, designed for an ice skating rink, its walls were blank. four corner towers set off the fifth, which rose from the centre sheer to a height of feet. the cheering coolness of this building was destined not to last. early in the afternoon of july th flames burst out from the top of the central tower. delaying his departure until he had provided against explosion, the brave engineer barely saved his life. firemen were soon on hand. sixteen of them forthwith made their way to the balcony near the blazing summit. suddenly their retreat was cut off by a burst of fire from the base of the tower. the rope and hose parted and precipitated a number who were sliding back to the roof. others leaped from the colossal torch. in an instant, it seemed, the whole pyre was swathed in flames. as it toppled, the last wretched form was seen to poise and plunge with it into the glowing abyss. the fisheries building received much attention. its pillars were twined with processions of aquatic creatures and surmounted by capitals quaintly resembling lobster-pots. its balustrades were supported by small fishy caryatids. if wonder fatigued the visitor, he reached sequestered shade and quiet upon the wooded island, where nearly every variety of american tree and shrub might be seen. the government's displays were of extreme interest. the war department exhibits showed our superiority in heavy ordnance, likewise that of europe in small arms. a first-class post-office was operated on the grounds. a combination postal car, manned by the most expert sorters and operators, interested vast crowds. close by was an ancient mail coach once actually captured by the indians, with effigies of the pony express formerly so familiar on the western plains, of a mail sledge drawn by dogs, and of a mail carrier mounted on a bicycle. models of a quaint little mississippi mail steamer and of the ocean steamer paris stood side by side. [illustration: two large domed buildings.] the administration building, seen from the agricultural building. swarms visited the midway plaisance, a long avenue out from the fair grounds proper, lined with shows. here were villages transported from the ends of the earth, animal shows, theatres, and bazaars. cairo street boasted , , visitors, and the hagenbeck circus over , , . the chief feature was the ferris wheel, described in engineering terms as a cantilever bridge wrought around two enormous bicycle wheels. the axle, supported upon steel pyramids, alone weighed more than a locomotive. in cars strung upon its periphery passengers were swung from the ground far above the highest buildings. [illustration: several hundred guests.] midway plaisance, world's fair, chicago. facilitating passenger transportation to and from the fair remarkable railway achievements were made. one train from new york to chicago covered over miles an hour, including stops. in preparation for the event the illinois central raised its tracks for two and a half miles over thirteen city streets, built special cars, and erected many new stations. these improvements cost over $ , , . the fair increased illinois central traffic over per cent. save the art building, the structures at the fair were designed to be temporary, and they were superfluous when the occasion which called them into being had passed. the question of disposing of them was summarily solved. one day some boys playing near the terminal station saw a sinister leer of flame inside. a high wind soon blew a conflagration, which enveloped the structures, leaving next day naught but ashes, tortured iron work, and here and there an arch, to tell of the regal white city that had been. [illustration: smoke pouring from a large building.] electricity building. mines and mining building. the burning of the white city. the financial backers of the fair showed no mercenary temper. the architects, too, worked with public spirit and zeal which money never could have elicited. notwithstanding the world's fair was not financially a "success," this was rather to the credit of its unstinted magnificence than to the want of public appreciation. the paid admissions were over , , , a daily average of , . the gross attendance exceeded by nearly a million the number at the paris exposition of for the corresponding period, though rather more than half a million below the total at the french capital. the monthly average at chicago increased from , , at first to , , in october. the crowd was typical of the best side of american life; orderly, good-natured, intelligent, sober. the grounds were clean, and there was no ruffianism. of the $ , worth of property reported stolen, $ , was recovered and restored. [illustration: very truly yours ichabod washburn] captains of industry or men of business who did something besides making money _a book for young americans_ by james parton fifth thousand [illustration] boston houghton, mifflin and company new york: east seventeenth street the riverside press, cambridge copyright, , by james parton. _all rights reserved._ _the riverside press, cambridge, mass., u. s. a._ electrotyped and printed by h. o. houghton & company. preface. in this volume are presented examples of men who shed lustre upon ordinary pursuits, either by the superior manner in which they exercised them or by the noble use they made of the leisure which success in them usually gives. such men are the nobility of republics. the american people were fortunate in having at an early period an ideal man of this kind in benjamin franklin, who, at the age of forty-two, just mid-way in his life, deliberately relinquished the most profitable business of its kind in the colonies for the sole purpose of developing electrical science. in this, as in other respects, his example has had great influence with his countrymen. a distinguished author, who lived some years at newport, has expressed the opinion that the men who occupy the villas of that emerald isle exert very little power compared with that of an orator or a writer. to be, he adds, at the head of a normal school, or to be a professor in a college, is to have a sway over the destinies of america which reduces to nothingness the power of successful men of business. being myself a member of the fraternity of writers, i suppose i ought to yield a joyful assent to such remarks. it is flattering to the self-love of those who drive along bellevue avenue in a shabby hired vehicle to be told that they are personages of much more consequence than the heavy capitalist who swings by in a resplendent curricle, drawn by two matched and matchless steeds, in a six-hundred dollar harness. perhaps they are. but i advise young men who aspire to serve their generation effectively not to undervalue the importance of the gentleman in the curricle. one of the individuals who has figured lately in the society of newport is the proprietor of an important newspaper. he is not a writer, nor a teacher in a normal school, but he wields a considerable power in this country. fifty men write for the journal which he conducts, some of whom write to admiration, for they are animated by a humane and patriotic spirit. the late lamented ivory chamberlain was a writer whose leading editorials were of national value. but, mark: a telegram of ten words from that young man at newport, written with perspiring hand in a pause of the game of polo, determines without appeal the course of the paper in any crisis of business or politics. i do not complain of this arrangement of things. i think it is just; i know it is unalterable. it is then of the greatest possible importance that the men who control during their lifetime, and create endowments when they are dead, should share the best civilization of their age and country. it is also of the greatest importance that young men whom nature has fitted to be leaders should, at the beginning of life, take to the steep and thorny path which leads at length to mastership. most of these chapters were published originally in "the ledger" of new york, and a few of them in "the youths' companion" of boston, the largest two circulations in the country. i have occasionally had reason to think that they were of some service to young readers, and i may add that they represent more labor and research than would be naturally supposed from their brevity. perhaps in this new form they may reach and influence the minds of future leaders in the great and growing realm of business. i should pity any young man who could read the briefest account of what has been done in manufacturing towns by such men as john smedley and robert owen without forming a secret resolve to do something similar if ever he should win the opportunity. table of contents. page david maydole, hammer-maker ichabod washburn, wire-maker elihu burritt, the learned blacksmith michael reynolds, engine-driver major robert pike, farmer george graham, clock-maker, buried in westminster abbey john harrison, exquisite watch-maker peter faneuil, and the great hall he built chauncey jerome, yankee clock-maker captain pierre laclede liguest, pioneer israel putnam, farmer george flower, pioneer edward coles, noblest of the pioneers, and his great speech peter h. burnett, banker gerrit smith peter force, printer john bromfield, merchant frederick tudor, ice exporter myron holley, market-gardener the founders of lowell robert owen, cotton-manufacturer john smedley, stocking-manufacturer richard cobden, calico printer henry bessemer john bright, manufacturer thomas edward, cobbler and naturalist robert dick, baker and naturalist john duncan, weaver and botanist james lackington, second-hand bookseller horace greeley's start james gordon bennett, and how he founded his "herald" three john walters, and their newspaper george hope sir henry cole charles summers william b. astor, house-owner peter cooper paris-duverney, french financier sir rowland hill marie-antoine carème, french cook wonderful walker, parson of all work sir christopher wren sir john rennie, engineer sir moses montefiore marquis of worcester, inventor of the steam-engine an old dry-goods merchant's recollections portraits. page ichabod washburn _frontispiece._ chauncey jerome gerrit smith myron holley john bright john duncan peter cooper sir rowland hill captains of industry. david maydole, hammer-maker. when a young man begins to think of making his fortune, his first notion usually is to go away from home to some very distant place. at present, the favorite spot is colorado; awhile ago it was california; and old men remember when buffalo was about as far west as the most enterprising person thought of venturing. it is not always a foolish thing to go out into the world far beyond the parent nest, as the young birds do in midsummer. but i can tell you, boys, from actual inquiry, that a great number of the most important and famous business men of the united states struck down roots where they were first planted, and where no one supposed there was room or chance for any large thing to grow. i will tell you a story of one of these men, as i heard it from his own lips some time ago, in a beautiful village where i lectured. he was an old man then; and a curious thing about him was that, although he was too deaf to hear one word of a public address, even of the loudest speaker, he not only attended church every sunday, but was rarely absent when a lecture was delivered. while i was performing on that occasion, i saw him sitting just in front of the platform, sleeping the sleep of the just till the last word was uttered. upon being introduced to this old gentleman in his office, and learning that his business was to make hammers, i was at a loss for a subject of conversation, as it never occurred to me that there was anything to be said about hammers. i have generally possessed a hammer, and frequently inflicted damage on my fingers therewith, but i had supposed that a hammer was simply a hammer, and that hammers were very much alike. at last i said,-- "and here you make hammers for mankind, mr. maydole?" you may have noticed the name of david maydole upon hammers. he is the man. "yes," said he, "i have made hammers here for twenty-eight years." "well, then," said i, shouting in his best ear, "by this time you ought to be able to make a pretty good hammer." "no, i can't," was his reply. "i can't make a pretty good hammer. i make the best hammer that's made." that was strong language. i thought, at first, he meant it as a joke; but i soon found it was no joke at all. he had made hammers the study of his lifetime, and, after many years of thoughtful and laborious experiment, he had actually produced an article, to which, with all his knowledge and experience, he could suggest no improvement. i was astonished to discover how many points there are about an instrument which i had always supposed a very simple thing. i was surprised to learn in how many ways a hammer can be bad. but, first, let me tell you how he came to think of hammers. there he was, forty years ago, in a small village of the state of new york; no railroad yet, and even the erie canal many miles distant. he was the village blacksmith, his establishment consisting of himself and a boy to blow the bellows. he was a good deal troubled with his hammers. sometimes the heads would fly off. if the metal was too soft, the hammer would spread out and wear away; if it was too hard, it would split. at that time blacksmiths made their own hammers, and he knew very little about mixing ores so as to produce the toughest iron. but he was particularly troubled with the hammer getting off the handle, a mishap which could be dangerous as well as inconvenient. at this point of his narrative the old gentleman showed a number of old hammers, such as were in use before he began to improve the instrument; and it was plain that men had tried very hard before him to overcome this difficulty. one hammer had an iron rod running down through the handle with a nut screwed on at the end. another was wholly composed of iron, the head and handle being all of one piece. there were various other devices, some of which were exceedingly clumsy and awkward. at last, he hit upon an improvement which led to his being able to put a hammer upon a handle in such a way that it would stay there. he made what is called an adze-handled hammer, the head being attached to the handle after the manner of an adze. the improvement consists in merely making _a longer hole_ for the handle to go into, by which device it has a much firmer hold of the head, and can easily be made extremely tight. with this improvement, if the handle is well seasoned and well wedged, there is no danger of the head flying off. he made some other changes, all of them merely for his own convenience, without a thought of going into the manufacture of hammers. the neighborhood in which he lived would have scarcely required half a dozen new hammers per annum. but one day there came to the village six carpenters to work upon a new church, and one of these men, having left his hammer at home, came to david maydole's blacksmith's shop to get one made. "make me as good a hammer," said the carpenter, "as you know how." that was touching david upon a tender place. "as good a one as i know how?" said he. "but perhaps you don't want to pay for as good a one as i know how to make." "yes, i do," replied the man; "i want a good hammer." the blacksmith made him one of his best. it was probably the best hammer that had ever been made in the world, since it contained two or three important improvements never before combined in the instrument. the carpenter was delighted with it, and showed it, with a good deal of exultation, to his five companions; every man of whom came the next day to the shop and wanted one just like it. they did not understand all the blacksmith's notions about tempering and mixing the metals, but they saw at a glance that the head and the handle were so united that there never was likely to be any divorce between them. to a carpenter building a wooden house, the mere removal of that one defect was a boon beyond price; he could hammer away with confidence, and without fear of seeing the head of his hammer leap into the next field, unless stopped by a comrade's head. when all the six carpenters had been supplied with these improved hammers, the contractor came and ordered two more. he seemed to think, and, in fact, said as much, that the blacksmith ought to make _his_ hammers a little better than those he had made for the men. "i can't make any better ones," said honest david. "when i make a thing, i make it as well as i can, no matter who it's for." soon after, the store-keeper of the village, seeing what excellent hammers these were, gave the blacksmith a magnificent order for two dozen, which, in due time, were placed upon his counter for sale. at this time something happened to david maydole which may fairly be called good luck; and you will generally notice events of the kind in the lives of meritorious men. "fortune favors the brave," is an old saying, and good luck in business is very apt to befall the man who could do very well without it. it so happened that a new york dealer in tools, named wood, whose store is still kept in chatham street, new york, happened to be in the village getting orders for tools. as soon as his eye fell upon those hammers, he saw their merits, and bought them all. he did more. he left a standing order for as many hammers of that kind as david maydole could make. that was the beginning. the young blacksmith hired a man or two, then more men, and made more hammers, and kept on making hammers during the whole of his active life, employing at last a hundred and fifteen men. during the first twenty years, he was frequently experimenting with a view to improve the hammer. he discovered just the best combination of ores to make his hammers hard enough, without being too hard. he gradually found out precisely the best form of every part. there is not a turn or curve about either the handle or the head which has not been patiently considered, and reconsidered, and considered again, until no further improvement seemed possible. every handle is seasoned three years, or until there is no shrink left in it. perhaps the most important discovery which he made was that a perfect tool cannot be made by machinery. naturally, his first thought, when he found his business increasing, was to apply machinery to the manufacture, and for some years several parts of the process were thus performed. gradually, his machines were discarded, and for many years before his retirement, every portion of the work was done by hand. each hammer is hammered out from a piece of iron, and is tempered over a slow charcoal fire, under the inspection of an experienced man. he looks as though he were cooking his hammers on a charcoal furnace, and he watches them until the process is complete, as a cook watches mutton chops. i heard some curious things about the management of this business. the founder never did anything to "push" it. he never advertised. he never reduced the price of his hammers because other manufacturers were doing so. his only care, he said, had been to make a perfect hammer, to make just as many of them as people wanted, and _no more_, and to sell them at a fair price. if people did not want his hammers, he did not want to make them. if they did not want to pay what they were worth, they were welcome to buy cheaper ones of some one else. for his own part, his wants were few, and he was ready at any time to go back to his blacksmith's shop. the old gentleman concluded his interesting narration by making me a present of one of his hammers, which i now cherish among my treasures. if it had been a picture, i should have had it framed and hung up over my desk, a perpetual admonition to me to do my work well; not too fast; not too much of it; not with any showy false polish; not letting anything go till i had done all i could to make it what it should be. in telling this little story, i have told thousands of stories. take the word _hammer_ out of it, and put _glue_ in its place, and you have the history of peter cooper. by putting in other words, you can make the true history of every great business in the world which has lasted thirty years. the true "protective system," of which we hear so much, is _to make the best article_; and he who does this need not buy a ticket for colorado. ichabod washburn, wire-maker. of all our manufactures few have had a more rapid development than wire-making. during the last thirty years the world has been girdled by telegraphic wires and cables, requiring an immense and continuous supply of the article. in new york alone two hundred pianos a week have been made, each containing miles of wire. there have been years during which a garment composed chiefly of wire was worn by nearly every woman in the land, even by the remotest and poorest. who has supplied all these millions of miles of wire? a large part of the answer to this question is given when we pronounce the name at the head of this article, ichabod washburn. in the last years of his life he had seven hundred men at worcester making wire, the product of whose labor was increased a hundred fold by machinery which he had invented or adapted. it is curious to note how he seemed to stumble into the business just in the nick of time. i say, _seemed_; but, in truth, he had been prepared for success in it by a long course of experience and training. he was a poor widow's son, born on the coast of massachusetts, a few miles from plymouth rock; his father having died in early manhood, when this boy and a twin brother were two months old. his mother, suddenly left with three little children, and having no property except the house in which she lived, supported her family by weaving, in which her children from a very early age could give her some help. she kept them at school, however, during part of the winter, and instilled into their minds good principles. when this boy was nine years of age she was obliged, as the saying was, "to put him out to live" to a master five miles from her house. on his way to his new home he was made to feel the difference between a hard master and a kind mother. having a quick intelligent mind, he questioned the man concerning the objects they passed. at length the boy saw a windmill, and he asked what that was. "don't ask me so many questions, boy," answered the man, in a harsh, rough voice. the little fellow was silenced, and he vividly remembered the event, the tone, and the scene, to old age. his employer was a maker of harness, carriages, and trunks, and it was the boy's business to take care of a horse and two cows, light fires, chop wood, run errands, and work in the shop. he never forgot the cold winter mornings, and the loud voice of his master rousing him from sleep to make the fire, and go out to the barn and get the milking done before daylight. his sleeping-place was a loft above the shop reached by a ladder. being always a timid boy, he suffered extremely from fear in the dark and lonely garret of a building where no one else slept, and to which he had to grope his way alone. what would the dainty boys of the present time think of going to mill on a frosty morning astride of a bag of corn on the horse's back, without stockings or shoes and with trousers half way up to the knees? on one occasion the little ichabod was so thoroughly chilled that he had to stop at a house to get warm, and the good woman took pity on him, made him put on a pair of long black stockings, and a pair of her own shoes. thus equipped, with his long black legs extending far out of his short trousers, and the woman's shoes lashed to his feet, he presented a highly ludicrous appearance, and one which, he thought, might have conveyed a valuable hint to his master. in the daytime he was usually employed in the shop making harnesses, a business in which he became expert. he served this man five years, or until he was fourteen years of age, when he made a complete harness for one of his cousins, which rendered excellent service for many years, and a part of it lasted almost as long as the maker. thus, at fourteen, he had completed his first apprenticeship, and had learned his first trade. the war of having given a sudden start to manufactures in this country, he went to work in a cotton factory for a while, where, for the first time in his life, he saw complicated machinery. like a true yankee as he was, he was strongly attracted by it, and proposed to learn the machinist's trade. his guardian opposed the scheme strongly, on the ground that, in all probability, by the time he had learned the trade the country would be so full of factories that there would be no more machinery required. thus discouraged, he did the next best thing: he went apprentice to the blacksmith's trade, near worcester, where he was destined to spend the rest of his life. he was sixteen years of age when he began this second apprenticeship; but he was still one of the most timid and bashful of lads. in a fragment of autobiography found among his papers after his death he says:-- "i arrived at worcester about one o'clock, at syke's tavern where we were to dine; but the sight of the long table in the dining-room so overpowered my bashful spirit that i left the room and went into the yard without dinner to wait till the stage was ready." on reaching his new home, eighty miles from his mother's house, he was so overcome by homesickness that, the first night, he sobbed himself to sleep. soon he became interested in his shop and in his work, made rapid progress, and approved himself a skillful hand. having been brought up to go to church every sunday, he now hired a seat in the gallery of one of the churches at fifty cents a year, which he earned in over-time by forging pot-hooks. every cent of his spending money was earned in similar ways. once he made six toasting-irons, and carried them to worcester, where he sold them for a dollar and a quarter each, taking a book in part payment. when his sister was married he made her a wedding present of a toasting-iron. nor was it an easy matter for an apprentice then to do work in over-time, for he was expected to labor in his master's service from sunrise to sunset in the summer, and from sunrise to nine o'clock in the winter. on a bright day in august, , his twentieth birthday, he was out of his time, and, according to the custom of the period, he celebrated the joyful event by a game of ball! in a few months, having saved a little money, he went into business as a manufacturer of ploughs, in which he had some little success. but still yearning to know more of machinery he entered upon what we may call his third apprenticeship, in an armory near worcester, where he soon acquired skill enough to do the finer parts of the work. then he engaged in the manufacture of lead pipe, in which he attained a moderate success. at length, in , being then thirty-three years old, he began the business of making wire, in which he continued during the remainder of his active life. the making of wire, especially the finer and better kinds, is a nice operation. until ichabod washburn entered into the business, wire of good quality was not made in the united states; and there was only one house in great britain that had the secret of making the steel wire for pianos, and they had had a monopoly of the manufacture for about eighty years. wire is made by drawing a rod of soft, hot iron through a hole which is too small for it. if a still smaller sized wire is desired, it is drawn through a smaller hole, and this process is repeated until the required size is attained. considerable power is needed to draw the wire through, and the hole through which it is drawn is soon worn larger. the first wire machine that washburn ever saw was arranged with a pair of self-acting pincers which drew a foot of wire and then had to let go and take a fresh hold. by this machine a man could make fifty pounds of coarse wire in a day. he soon improved this machine so that the pincers drew fifteen feet without letting go; and by this improvement alone the product of one man's labor was increased about eleven times. a good workman could make five or six hundred pounds a day by it. by another improvement which washburn adopted the product was increased to twenty-five hundred pounds a day. he was now in his element. he always had a partner to manage the counting-room part of the business, which he disliked. "i never," said he, "had taste or inclination for it, always preferring to be among the machinery, doing the work and handling the tools i was used to, though oftentimes at the expense of a smutty face and greasy hands." his masterpiece in the way of invention was his machinery for making steel wire for pianos,--a branch of the business which was urged upon him by the late jonas chickering, piano manufacturer, of boston. the most careless glance at the strings of a piano shows us that the wire must be exquisitely tempered and most thoroughly wrought, in order to remain in tune, subjected as they are to a steady pull of many tons. washburn experimented for years in perfecting his process, and he was never satisfied until he was able to produce a wire which he could honestly claim to be the best in the world. he had amazing success in his business. at one time he was making two hundred and fifty thousand yards of crinoline wire every day. his whole daily product was seven tons of iron wire, and five tons of steel wire. this excellent man, in the midst of a success which would have dazzled and corrupted some men, retained all the simplicity, the modesty, and the generosity of his character. he felt, as he said, nowhere so much at home as among his own machinery, surrounded by thoughtful mechanics, dressed like them for work, and possibly with a black smudge upon his face. in his person, however, he was scrupulously clean and nice, a hater of tobacco and all other polluting things and lowering influences. rev. h. t. cheever, the editor of his "memorials," mentions also that he remained to the end of his life in the warmest sympathy with the natural desires of the workingman. he was a collector of facts concerning the condition of workingmen everywhere, and for many years cherished a project of making his own business a coöperative one. "he believed," remarks mr. cheever, "that the skilled and faithful manual worker, as well as the employer, was entitled to a participation in the net proceeds of business, over and above his actual wages. he held that in this country the entire people are one great working class, working with brains, or hands, or both, who should therefore act in harmony--the brain-workers and the hand-workers--for the equal rights of all, without distinction of color, condition, or religion. holding that capital is accumulated labor, and wealth the creation of capital and labor combined, he thought it to be the wise policy of the large capitalists and corporations to help in the process of elevating and advancing labor by a proffered interest." these were the opinions of a man who had had long experience in all the grades, from half-frozen apprentice to millionaire manufacturer. he died in , aged seventy-one years, leaving an immense estate; which, however, chiefly consisted in his wire-manufactory. he had made it a principle not to accumulate money for the sake of money, and he gave away in his lifetime a large portion of his revenue every year. he bequeathed to charitable associations the sum of four hundred and twenty-four thousand dollars, which was distributed among twenty-one objects. his great bequests were to institutions of practical and homely benevolence: to the home for aged women and widows, one hundred thousand dollars; to found a hospital and free dispensary, the same amount; smaller sums to industrial schools and mission schools. it was one of his fixed convictions that boys cannot be properly fitted for life without being both taught and required to use their hands, as well as their heads, and it was long his intention to found some kind of industrial college. finding that something of the kind was already in existence at worcester, he made a bequest to it of one hundred and ten thousand dollars. the institution is called the worcester county free institute of industrial science. elihu burritt, the learned blacksmith. elihu burritt, with whom we have all been familiar for many years as the learned blacksmith, was born in at the beautiful town of new britain, in connecticut, about ten miles from hartford. he was the youngest son in an old-fashioned family of ten children. his father owned and cultivated a small farm; but spent the winters at the shoemaker's bench, according to the rational custom of connecticut in that day. when elihu was sixteen years of age, his father died and the lad soon after apprenticed himself to a blacksmith in his native village. he was an ardent reader of books from childhood up; and he was enabled to gratify this taste by means of a small village library, which contained several books of history, of which he was naturally fond. this boy, however, was a shy, devoted student, brave to maintain what he thought right, but so bashful that he was known to hide in the cellar when his parents were going to have company. as his father's long sickness had kept him out of school for some time, he was the more earnest to learn during his apprenticeship; particularly mathematics, since he desired to become, among other things, a good surveyor. he was obliged to work from ten to twelve hours a day at the forge; but while he was blowing the bellows he employed his mind in doing sums in his head. his biographer gives a specimen of these calculations which he wrought out without making a single figure:-- "how many yards of cloth, three feet in width, cut into strips an inch wide, and allowing half an inch at each end for the lap, would it require to reach from the centre of the earth to the surface, and how much would it all cost at a shilling a yard?" he would go home at night with several of these sums done in his head, and report the results to an elder brother who had worked his way through williams college. his brother would perform the calculations upon a slate, and usually found his answers correct. when he was about half through his apprenticeship he suddenly took it into his head to learn latin, and began at once through the assistance of the same elder brother. in the evenings of one winter he read the Æneid of virgil; and, after going on for a while with cicero and a few other latin authors, he began greek. during the winter months he was obliged to spend every hour of daylight at the forge, and even in the summer his leisure minutes were few and far between. but he carried his greek grammar in his hat, and often found a chance, while he was waiting for a large piece of iron to get hot, to open his book with his black fingers, and go through a pronoun, an adjective or part of a verb, without being noticed by his fellow-apprentices. so he worked his way until he was out of his time, when he treated himself to a whole quarter's schooling at his brother's school, where he studied mathematics, latin and other languages. then he went back to the forge, studying hard in the evenings at the same branches, until he had saved a little money; when he resolved to go to new haven, and spend a winter in study. it was far from his thoughts, as it was from his means, to enter yale college; but he seems to have had an idea that the very atmosphere of the college would assist him. he was still so timid that he determined to work his way without asking the least assistance from a professor or tutor. he took lodgings at a cheap tavern in new haven, and began the very next morning a course of heroic study. as soon as the fire was made in the sitting-room of the inn, which was at half-past four in the morning, he took possession, and studied german until breakfast-time, which was half-past seven. when the other boarders had gone to business, he sat down to homer's iliad, of which he knew nothing, and with only a dictionary to help him. "the proudest moment of my life," he once wrote, "was when i had first gained the full meaning of the first fifteen lines of that noble work. i took a short triumphal walk in favor of that exploit." just before the boarders came back for their dinner, he put away all his greek and latin books, and took up a work in italian, because it was less likely to attract the notice of the noisy crowd. after dinner he fell again upon his greek, and in the evening read spanish until bed-time. in this way he lived and labored for three months, a solitary student in the midst of a community of students; his mind imbued with the grandeurs and dignity of the past, while eating flapjacks and molasses at a poor tavern. returning to his home in new britain, he obtained the mastership of an academy in a town near by: but he could not bear a life wholly sedentary; and, at the end of a year, abandoned his school and became what is called a "runner" for one of the manufacturers of new britain. this business he pursued until he was about twenty-five years of age, when, tired of wandering, he came home again, and set up a grocery and provision store, in which he invested all the money he had saved. soon came the commercial crash of , and he was involved in the widespread ruin. he lost the whole of his capital, and had to begin the world anew. he resolved to return to his studies in the languages of the east. unable to buy or find the necessary books, he tied up his effects in a small handkerchief, and walked to boston, one hundred miles distant, hoping there to find a ship in which he could work his passage across the ocean, and collect oriental works from port to port. he could not find a berth. he turned back, and walked as far as worcester, where he found work, and found something else which he liked better. there is an antiquarian society at worcester, with a large and peculiar library, containing a great number of books in languages not usually studied, such as the icelandic, the russian, the celtic dialects, and others. the directors of the society placed all their treasures at his command, and he now divided his time between hard study of languages and hard labor at the forge. to show how he passed his days, i will copy an entry or two from a private diary he then kept:-- "monday, june . headache; pages cuvier's theory of the earth; pages french; hours forging. "tuesday, june . lines hebrew; pages french; pages of cuvier; lines syriac; lines danish; lines bohemian; lines polish; names of stars; hours forging. "wednesday, june . lines hebrew; lines syriac; hours forging." he spent five years at worcester in such labors as these. when work at his trade became slack, or when he had earned a little more money than usual, he would spend more time in the library; but, on the other hand, when work in the shop was pressing, he could give less time to study. after a while, he began to think that he might perhaps earn his subsistence in part by his knowledge of languages, and thus save much waste of time and vitality at the forge. he wrote a letter to william lincoln, of worcester, who had aided and encouraged him; and in this letter he gave a short history of his life, and asked whether he could not find employment in translating some foreign work into english. mr. lincoln was so much struck with his letter that he sent it to edward everett, and he having occasion soon after to address a convention of teachers, read it to his audience as a wonderful instance of the pursuit of knowledge under difficulties. mr. everett prefaced it by saying that such a resolute purpose of improvement against such obstacles excited his admiration, and even his veneration. "it is enough," he added, "to make one who has good opportunities for education hang his head in shame." all this, including the whole of the letter, was published in the newspapers, with eulogistic comments, in which the student was spoken of as the learned blacksmith. the bashful scholar was overwhelmed with shame at finding himself suddenly famous. however, it led to his entering upon public life. lecturing was then coming into vogue, and he was frequently invited to the platform. accordingly, he wrote a lecture, entitled "application and genius," in which he endeavored to show that there is no such thing as genius, but that all extraordinary attainments are the results of application. after delivering this lecture sixty times in one season, he went back to his forge at worcester, mingling study with labor in the old way. on sitting down to write a new lecture for the following season, on the "anatomy of the earth," a certain impression was made upon his mind, which changed the current of his life. studying the globe, he was impressed with the _need_ that one nation has of other nations, and one zone of another zone; the tropics producing what assuages life in the northern latitudes, and northern lands furnishing the means of mitigating tropical discomforts. he felt that the earth was made for friendliness and coöperation, not for fierce competition and bloody wars. under the influence of these feelings, his lecture became an eloquent plea for peace, and to this object his after life was chiefly devoted. the dispute with england upon the oregon boundary induced him to go to england, with the design of traveling on foot from village to village, preaching peace, and exposing the horrors and folly of war. his addresses attracting attention, he was invited to speak to larger bodies, and, in short, he spent twenty years of his life as a lecturer upon peace, organizing peace congresses, advocating low uniform rates of ocean postage, and spreading abroad among the people of europe the feeling which issued, at length, in the arbitration of the dispute between the united states and great britain; an event which posterity will, perhaps, consider the most important of this century. he heard victor hugo say at the paris congress of :-- "a day will come when a cannon will be exhibited in public museums, just as an instrument of torture is now, and people will be amazed that such a thing could ever have been." if he had sympathetic hearers, he produced upon them extraordinary effects. nathaniel p. rogers, one of the heroes of the anti-slavery agitation, chanced to hear him in boston in on his favorite subject of peace. he wrote soon after:-- "i had been introduced to elihu burritt the day before, and was much interested in his original appearance, and desirous of knowing him further. i had not formed the highest opinion of his liberality. but on entering the hall my friends and i soon forgot everything but the speaker. the dim-lit hall, the handful audience, the contrast of both with the illuminated chapel and ocean multitude assembled overhead, bespeak painfully the estimation in which the great cause of peace is held in christendom. i wish all christendom could have heard elihu burritt's speech. one unbroken, unabated stream it was of profound and lofty and original eloquence. i felt riveted to my seat till he finished it. there was no oratory about it, in the ordinary sense of that word; no graces of elocution. it was mighty thoughts radiating off from his heated mind like the sparkles from the glowing steel on his own anvil, getting on as they come out what clothing of language they might, and thus having on the most appropriate and expressive imaginable. not a waste word, nor a wanting one. and he stood and delivered himself in a simplicity and earnestness of attitude and gesture belonging to his manly and now honored and distinguished trade. i admired the touch of rusticity in his accent, amid his truly splendid diction, which betokened, as well as the vein of solid sense that ran entirely through his speech, that he had not been educated at the college. i thought of ploughman burns as i listened to blacksmith burritt. oh! what a dignity and beauty labor imparts to learning." elihu burritt spent the last years of his life upon a little farm which he had contrived to buy in his native town. he was never married, but lived with his sister and her daughters. he was not so very much richer in worldly goods than when he had started for boston with his property wrapped in a small handkerchief. he died in march, , aged sixty-nine years. michael reynolds, engine-driver. literature in these days throws light into many an out-of-the-way corner. it is rapidly making us all acquainted with one another. a locomotive engineer in england has recently written a book upon his art, in order, as he says, "to communicate that species of knowledge which it is necessary for an engine-driver to possess who aspires to take high rank on the footplate!" he magnifies his office, and evidently regards the position of an engineer as highly enviable. "it is very _natural_," he remarks, "for those who are unacquainted with locomotive driving to admire the life of an engine-man, and to imagine how very pleasant it must be to travel on the engine. but they do not think of the gradations by which alone the higher positions are reached; they see only on the express engine the picturesque side of the result of many years of patient observation and toil." this passage was to me a revelation; for i had looked upon an engineer and his assistant with some compassion as well as admiration, and have often thought how extremely disagreeable it must be to travel on the engine as they do. not so michael reynolds, the author of this book, who has risen from the rank of fireman to that of locomotive inspector on the london and brighton railroad. he tells us that a model engineer "is possessed by a master passion--a passion for the monarch of speed." such an engineer is distinguished, also, for his minute knowledge of the engine, and nothing makes him happier than to get some new light upon one of its numberless parts. so familiar is he with it that his ear detects the slightest variation in the beats of the machinery, and can tell the shocks and shakes which are caused by a defective road from those which are due to a defective engine. even his nose acquires a peculiar sensitiveness. in the midst of so much heat, he can detect that which arises from friction before any mischief has been done. at every rate of speed he knows just how his engine ought to sound, shake, and smell. let us see how life passes on a locomotive, and what is the secret of success in the business of an engineer. the art of arts in engine-driving is the management of the fire. every reader is aware that taking care of a fire is something in which few persons become expert. most of us think that we ourselves possess the knack of it, but not another individual of our household agrees with us. now, a man born with a genius for managing a locomotive is one who has a high degree of the fire-making instinct. mr. reynolds distinctly says that a man may be a good mechanic, may have even built locomotives, and yet, if he is not a good "shovel-man," if he does not know how to manage his fire, he will never rise to distinction in his profession. the great secret is to build the fire so that the whole mass of fuel will ignite and burn freely without the use of the blower, and so bring the engine to the train with a fire that will last. when we see an engine blowing off steam furiously at the beginning of the trip, we must not be surprised if the train reaches the first station behind time, since it indicates a fierce, thin fire, that has been rapidly ignited by the blower. an accomplished engineer backs his engine to the train without any sign of steam or smoke, but with a fire so strong and sound that he can make a run of fifty miles in an hour without touching it. the engineer, it appears, if he has an important run to make, comes to his engine an hour before starting. his first business, on an english railroad, is to read the notices, posted up in the engine house, of any change in the condition of the road requiring special care. his next duty is to inspect his engine in every part: first, to see if there is water enough in the boiler, and that the fire is proceeding properly; then, that he has the necessary quantity of water and coal in the tender. he next gets into the pit under his engine, with the proper tools, and inspects every portion of it, trying every nut and pin within his reach from below. then he walks around the engine, and particularly notices if the oiling apparatus is exactly adjusted. some parts require, for example, four drops of oil every minute, and he must see that the apparatus is set so as to yield just that quantity. he is also to look into his tool-box, and see if every article is in its place. mr. reynolds enumerates twenty-two objects which a good engineer will always have within his reach, such as fire implements of various kinds, machinist tools, lamps of several sorts, oiling vessels, a quantity of flax and yarn, copper wire, a copy of the rules and his time-table; all of which, are to be in the exact place designed for them, so that they can be snatched in a moment. one of the chief virtues of the engineer and his companion, the fireman, is one which we are not accustomed to associate with their profession; and that is cleanliness. on this point our author grows eloquent, and he declares that a clean engineer is almost certain to be an excellent one in every particular. the men upon a locomotive cannot, it is true, avoid getting black smudge upon their faces. the point is that both the men and their engines should be clean in all the essential particulars, so that all the faculties of the men and all the devices of the engine shall work with ease and certainty. "there is something," he remarks, "so very degrading about dirt, that even a poor beast highly appreciates clean straw. cleanliness hath a charm that hideth a multitude of faults, and it is not difficult to trace a connection between habitual cleanliness and a respect for general order, for punctuality, for truthfulness, for all placed in authority." do you mark that sentence, reader? the spirit of the saxon race speaks in those lines. you observe that this author ranks among the virtues "a respect for all placed in authority." that, of course, may be carried too far; nevertheless, the strong races, and the worthy men of all races, do cherish a respect for lawful authority. a good soldier is _proud_ to salute his officer. on some english railroads both engineers and engines are put to tests much severer than upon roads elsewhere. between holyhead and chester, a distance of ninety-seven miles, the express trains run without stopping, and they do this with so little strain that an engine performed the duty every day for several years. a day's work of some crack engineers is to run from london to crewe and back again in ten hours, a distance of three hundred and thirty miles, stopping only at rugby for three minutes on each trip. there are men who perform this service every working day the whole year through, without a single delay. this is a very great achievement, and can only be done by engineers of the greatest skill and steadiness. it was long, indeed, before any man could do it, and even now there are engineers who dare not take the risk. on the hudson river road some of the trains run from new york to poughkeepsie, eighty miles, without stopping, but not every engineer could do it at first, and very often a train stopped at peekskill to take in water. the water is the difficulty, and the good engineer is one who wastes no water and no coal. mr. reynolds enumerates all the causes of accidents from the engine, many of which cannot be understood by the uninitiated. as we read them over, and see in how many ways an engine can go wrong, we wonder that a train ever arrives at its journey's end in safety. at the conclusion of this formidable list, the author confesses that it is incomplete, and notifies young engineers that _nobody_ can teach them the innermost secrets of the engine. some of these, he remarks, require "years of study," and even then they remain in some degree mysterious. nevertheless, he holds out to ambition the possibility of final success, and calls upon young men to concentrate all their energies upon the work. "self-reliance," he says, "is a grand element of character: it has won olympic crowns and isthmian laurels; it confers kinship with men who have vindicated their divine right to be held in the world's memory. let the master passion of the soul evoke undaunted energy in pursuit of the attainment of one end, aiming for the highest in the spirit of the lowest, prompted by the burning thought of reward, which sooner or later will come." we perceive that michael reynolds possesses one of the prime requisites of success: he believes in the worth and dignity of his vocation; and in writing this little book he has done something to elevate it in the regard of others. to judge from some of his directions, i should suppose that engineers in england are not, as a class, as well educated or as intelligent as ours. locomotive engineers in the united states rank very high in intelligence and respectability of character. major robert pike, farmer. i advise people who desire, above all things, to have a comfortable time in the world to be good conservatives. do as other people do, think as other people think, swim with the current--that is the way to glide pleasantly down the stream of life. but mark, o you lovers of inglorious ease, the men who are remembered with honor after they are dead do not do so! they sometimes _breast_ the current, and often have a hard time of it, with the water splashing back in their faces, and the easy-going crowd jeering at them as they pant against the tide. this valiant, stalwart puritan, major robert pike, of salisbury, massachusetts, who was born in , the year in which shakespeare died, is a case in point. salisbury, in the early day, was one of the frontier towns of massachusetts, lying north of the merrimac river, and close to the atlantic ocean. for fifty years it was a kind of outpost of that part of the state. it lay right in the path by which the indians of maine and canada were accustomed to slink down along the coast, often traveling on the sands of the beaches, and burst upon the settlements. during a long lifetime major pike was a magistrate and personage in that town, one of the leading spirits, upon whom the defense of the frontier chiefly devolved. others were as brave as he in fighting indians. many a man could acquit himself valiantly in battle who would not have the courage to differ from the public opinion of his community. but on several occasions, when massachusetts was wrong, major pike was right; and he had the courage sometimes to resist the current of opinion when it was swollen into a raging torrent. he opposed, for example, the persecution of the quakers, which is such a blot upon the records both of new england and old england. we can imagine what it must have cost to go against this policy by a single incident, which occurred in the year in robert pike's own town of salisbury. on a certain day in august, thomas macy was caught in a violent storm of rain, and hurried home drenched to the skin. he found in his house four wayfarers, who had also come in for shelter. his wife being sick in bed, no one had seen or spoken to them. they asked him how far it was to casco bay. from their dress and demeanor he thought they might be quakers, and, as it was unlawful to harbor persons of that sect, he asked them to go on their way, since he feared to give offense in entertaining them. as soon as the worst of the storm was over, they left, and he never saw them again. they were in his house about three quarters of an hour, during which he said very little to them, having himself come home wet, and found his wife sick. he was summoned to boston, forty miles distant, to answer for this offense. being unable to walk, and not rich enough to buy a horse, he wrote to the general court, relating the circumstances, and explaining his non-appearance. he was fined thirty shillings, and ordered to be admonished by the governor. he paid his fine, received his reprimand, and removed to the island of nantucket, of which he was the first settler, and for some time the only white inhabitant. during this period of quaker persecution, major pike led the opposition to it in salisbury, until, at length, william penn prevailed upon charles ii. to put an end to it in all his dominions. if the history of that period had not been so carefully recorded in official documents, we could scarcely believe to what a point the principle of authority was then carried. one of the laws which robert pike dared openly to oppose made it a misdemeanor for any one to exhort on sunday who had not been regularly ordained. he declared that the men who voted for that law had broken their oaths, for they had sworn on taking their seats to enact nothing against the just liberty of englishmen. for saying this he was pronounced guilty of "defaming" the legislature, and he was sentenced to be disfranchised, disabled from holding any public office, bound to good behavior, and fined twenty marks, equal to about two hundred dollars in our present currency. petitions were presented to the legislature asking the remission of the severe sentence. but even this was regarded as a criminal offense, and proceedings were instituted against every signer. a few acknowledged that the signing was an offense, and asked the forgiveness of the court, but all the rest were required to give bonds for their appearance to answer. another curious incident shows the rigor of the government of that day. according to the puritan law, sunday began at sunset on saturday evening, and ended at sunset on sunday evening. during the march thaw of , major pike had occasion to go to boston, then a journey of two days. fearing that the roads were about to break up, he determined to start on sunday evening, get across the merrimac, which was then a matter of difficulty during the melting of the ice, and make an early start from the other side of the river on monday morning. the gallant major being, of course, a member of the church, and very religious, went to church twice that sunday. now, as to what followed, i will quote the testimony of an eye-witness, his traveling companion:-- "i do further testify that, though it was pretty late ere mr. burrows (the clergyman) ended his afternoon's exercise, yet did the major stay in his daughter's house till repetition of both forenoon and afternoon sermons was over, and the duties of the day concluded with prayer; and, after a little stay, to be sure the sun was down, then we mounted, and not till then. the sun did indeed set in a cloud, and after we were mounted, i do remember the major spake of lightening up where the sun set; but i saw no sun." a personal enemy of the major's brought a charge against him of violating the holy day by starting on his journey _before_ the setting of the sun. the case was brought for trial, and several witnesses were examined. the accuser testified that "he did see major robert pike ride by his house toward the ferry upon the lord's day when the sun was about half an hour high." another witness confirmed this. another testified:-- "the sun did indeed set in a cloud, and, a little after the major was mounted, there appeared a light where the sun went down, which soon vanished again, possibly half a quarter of an hour." nevertheless, there were two witnesses who declared that the sun was not down when the major mounted, and so this worthy gentleman, then sixty-four years of age, a man of honorable renown in the commonwealth, was convicted of "profaning the sabbath," fined ten shillings, and condemned to pay costs and fees, which were eight shillings more. he paid his fine, and was probably more careful during the rest of his life to mount on sunday evenings by the almanac. the special glory of this man's life was his steadfast and brave opposition to the witchcraft mania of . this deplorable madness was in new england a mere transitory panic, from which the people quickly recovered; but while it lasted it almost silenced opposition, and it required genuine heroism to lift a voice against it. no country of europe was free from the delusion during that century, and some of its wisest men were carried away by it. the eminent judge, sir william blackstone, in his "commentaries," published in , used this language:-- "to deny the existence of witchcraft is to flatly contradict the revealed word of god, and the thing itself is a truth to which every nation has in its turn borne testimony." this was the conviction of that age, and hundreds of persons were executed for practicing witchcraft. in massachusetts, while the mania lasted, fear blanched every face and haunted every house. it was the more perilous to oppose the trials because there was a mingling of personal malevolence in the fell business, and an individual who objected was in danger of being himself accused. no station, no age, no merit, was a sufficient protection. mary bradbury, seventy-five years of age, the wife of one of the leading men of salisbury, a woman of singular excellence and dignity of character, was among the convicted. she was a neighbor of major pike's, and a life-long friend. in the height of the panic he addressed to one of the judges an argument against the trials for witchcraft which is one of the most ingenious pieces of writing to be found among the documents of that age. the peculiarity of it is that the author argues on purely biblical grounds; for he accepted the whole bible as authoritative, and all its parts as equally authoritative, from genesis to revelation. his main point was that witchcraft, whatever it may be, cannot be certainly proved against any one. the eye, he said, may be deceived; the ear may be; and all the senses. the devil himself may take the shape and likeness of a person or thing, when it is not that person or thing. the truth on the subject, he held, lay out of the range of mortal ken. "and therefore," he adds, "i humbly conceive that, in such a difficulty, it may be more safe, for the present, to let a guilty person live till further discovery than to put an innocent person to death." happily this mania speedily passed, and troubled new england no more. robert pike lived many years longer, and died in , when he was nearly ninety-one years of age. he was a farmer, and gained a considerable estate, the whole of which he gave away to his heirs before his death. the house in which he lived is still standing in the town of salisbury, and belongs to his descendants; for on that healthy coast men, families, and houses decay very slowly. james s. pike, one of his descendants, the well-remembered "j. s. p." of the "tribune's" earlier day, and now an honored citizen of maine, has recently written a little book about this ancient hero who assisted to set his fellow-citizens right when they were going wrong. george graham, clock-maker, buried in westminster abbey. it is supposed that the oldest clock in existence is one in the ancient castle of dover, on the southern coast of england, bearing the date, . it has been running, therefore, five hundred and thirty-six years. other clocks of the same century exist in various parts of europe, the works of which have but one hand, which points the hour, and require winding every twenty-four hours. from the fact of so many large clocks of that period having been preserved in whole or in part, it is highly probable that the clock was then an old invention. but how did people measure time during the countless ages that rolled away before the invention of the clock? the first time-measurer was probably a post stuck in the ground, the shadow of which, varying in length and direction, indicated the time of day, whenever the sun was not obscured by clouds. the sun-dial, which was an improvement upon this, was known to the ancient jews and greeks. the ancient chinese and egyptians possessed an instrument called the clepsydra (water-stealer), which was merely a vessel full of water with a small hole in the bottom by which the water slowly escaped. there were marks in the inside of the vessel which showed the hour. an improvement upon this was made about two hundred and thirty-five years before christ by an egyptian, who caused the escaping water to turn a system of wheels; and the motion was communicated to a rod which pointed to the hours upon a circle resembling a clock-face. similar clocks were made in which sand was used instead of water. the hour-glass was a time-measurer for many centuries in europe, and all the ancient literatures abound in allusions to the rapid, unobserved, running away of its sands. the next advance was the invention of the wheel-and-weight-clock, such as has been in use ever since. the first instrument of this kind may have been made by the ancients; but no clear allusion to its existence has been discovered earlier than , when pope sylvester ii. is known to have had one constructed. it was christian huygens, the famous dutch philosopher, who applied, in , the pendulum to the clock, and thus led directly to those more refined and subtle improvements, which render our present clocks and watches among the least imperfect of all human contrivances. george graham, the great london clock-maker of queen anne's and george the first's time, and one of the most noted improvers of the clock, was born in . after spending the first thirteen years of his life in a village in the north of england, he made his way to london, an intelligent and well-bred quaker boy; and there he was so fortunate as to be taken as an apprentice by tompion, then the most celebrated clock-maker in england, whose name is still to be seen upon ancient watches and clocks. tompion was a most exquisite mechanic, proud of his work and jealous of his name. he is the tompion who figured in farquhar's play of "the inconstant;" and prior mentions him in his "essay on learning," where he says that tompion on a watch or clock was proof positive of its excellence. a person once brought him a watch to repair, upon which his name had been fraudulently engraved. he took up a hammer and smashed it, and then selecting one of his own watches, gave it to the astonished customer, saying: "sir, here is a watch of my making." graham was worthy to be the apprentice of such a master, for he not only showed intelligence, skill, and fidelity, but a happy turn for invention. tompion became warmly attached to him, treated him as a son, gave him the full benefit of his skill and knowledge, took him into partnership, and finally left him sole possessor of the business. for nearly half a century george graham, clock-maker, was one of the best known signs in fleet street, and the instruments made in his shop were valued in all the principal countries of europe. the great clock at greenwich observatory, made by him one hundred and fifty years ago, is still in use and could hardly now be surpassed in substantial excellence. the mural arch in the same establishment, used for the testing of quadrants and other marine instruments, was also his work. when the french government sent maupertuis within the polar circle, to ascertain the exact figure of the earth, it was george graham, clock-maker of fleet street, who supplied the requisite instruments. but it was not his excellence as a mechanic that causes his name to be remembered at the present time. he made two capital inventions in clock-machinery which are still universally used, and will probably never be superseded. it was a common complaint among clock-makers, when he was a young man, that the pendulum varied in length according to the temperature, and consequently caused the clock to go too slowly in hot weather, and too fast in cold. thus, if a clock went correctly at a temperature of sixty degrees, it would lose three seconds a day if the temperature rose to seventy, and three more seconds a day for every additional ten degrees of heat. graham first endeavored to rectify this inconvenience by making the pendulum of several different kinds of metal, which was a partial remedy. but the invention by which he overcame the difficulty completely, consisted in employing a column of mercury as the "bob" of the pendulum. the hot weather, which lengthened the steel rods, raised the column of mercury, and so brought the centre of oscillation higher. if the column of mercury was of the right length, the lengthening or the shortening of the pendulum was exactly counterbalanced, and the variation of the clock, through changes of the temperature, almost annihilated. this was a truly exquisite invention. the clock he himself made on this plan for greenwich, after being in use a century and a half, requires attention not oftener than once in fifteen months. some important discoveries in astronomy are due to the exactness with which graham's clock measures time. he also invented what is called the "dead escapement," still used, i believe, in all clocks and watches, from the commonest five-dollar watch to the most elaborate and costly regulator. another pretty invention of his was a machine for showing the position and motions of the heavenly bodies, which was exceedingly admired by our grandfathers. lord orrery having amused himself by copying this machine, a french traveler who saw it complimented the maker by naming it an orrery, which has led many to suppose it to have been an invention of that lord. it now appears, however, that the true inventor was the fleet street clock-maker. the merits of this admirable mechanic procured for him, while he was still little more than a young man, the honor of being elected a member of the royal society, the most illustrious scientific body in the world. and a very worthy member he proved. if the reader will turn to the transactions of that learned society, he may find in them twenty-one papers contributed by george graham. he was, however, far from regarding himself as a philosopher, but to the end of his days always styled himself a clock-maker. they still relate an anecdote showing the confidence he had in his work. a gentleman who bought a watch of him just before departing for india, asked him how far he could depend on its keeping the correct time. "sir," replied graham, "it is a watch which i have made and regulated myself; take it with you wherever you please. if after seven years you come back to see me, and can tell me there has been a difference of five minutes, i will return you your money." seven years passed, and the gentleman returned. "sir," said he, "i bring you back your watch." "i remember," said graham, "our conditions. let me see the watch. well, what do you complain of?" "why," was the reply, "i have had it seven years, and there is a difference of more than five minutes." "indeed!" said graham. "in that case i return you your money." "i would not part with my watch," said the gentleman, "for ten times the sum i paid for it." "and i," rejoined graham, "would not break my word for any consideration." he insisted on taking back the watch, which ever after he used as a regulator. this is a very good story, and is doubtless substantially true; but no watch was ever yet made which has varied as little as five minutes in seven years. readers may remember that the british government once offered a reward of twenty thousand pounds sterling for the best chronometer, and the prize was awarded to harrison for a chronometer which varied two minutes in a sailing voyage from england to jamaica and back. george graham died in , aged seventy-six years, universally esteemed as an ornament of his age and country. in westminster abbey, among the tombs of poets, philosophers, and statesmen, may be seen the graves of the two clock-makers, master and apprentice, tompion and graham. john harrison, exquisite watch-maker. he was first a carpenter, and the son of a carpenter, born and reared in english yorkshire, in a village too insignificant to appear on any but a county map. faulby is about twenty miles from york, and there john harrison was born in , when william and mary reigned in england. he was thirty-five years of age before he was known beyond his own neighborhood. he was noted there, however, for being a most skillful workman. there is, perhaps, no trade in which the degrees of skill are so far apart as that of carpenter. the difference is great indeed between the clumsy-fisted fellow who knocks together a farmer's pig-pen, and the almost artist who makes a dining-room floor equal to a piece of mosaic. dr. franklin speaks with peculiar relish of one of his young comrades in philadelphia, as "the most exquisite joiner" he had ever known. it was not only in carpentry that john harrison reached extraordinary skill and delicacy of stroke. he became an excellent machinist, and was particularly devoted from an early age to clock-work. he was a student also in the science of the day. a contemporary of newton, he made himself capable of understanding the discoveries of that great man, and of following the transactions of the royal society in mathematics, astronomy, and natural philosophy. clock-work, however, was his ruling taste as a workman, for many years, and he appears to have set before him as a task the making of a clock that should surpass all others. he says in one of his pamphlets that, in the year , when he was thirty-three years of age, he finished two large pendulum clocks which, being placed in different houses some distance apart, differed from each other only one second in a month. he also says that one of his clocks, which he kept for his own use, the going of which he compared with a fixed star, varied from the true time only one minute in ten years. modern clock-makers are disposed to deride these extraordinary claims, particularly those of paris and switzerland. we know, however, that john harrison was one of the most perfect workmen that ever lived, and i find it difficult to believe that a man whose works were so true could be false in his words. in perfecting these amateur clocks he made a beautiful invention, the principle of which is still employed in other machines besides clock-work. like george graham, he observed that the chief cause of irregularity in a well-made clock was the varying length of the pendulum, which in warm weather expanded and became a little longer, and in cold weather became shorter. he remedied this by the invention of what is often called the gridiron pendulum, made of several bars of steel and brass, and so arranged as to neutralize and correct the tendency of the pendulum to vary in length. brass is very sensitive to changes of temperature, steel much less so; and hence it is not difficult to arrange the pendulum so that the long exterior bars of steel shall very nearly curb the expansion and contraction of the shorter brass ones. while he was thus perfecting himself in obscurity, the great world was in movement also, and it was even stimulating his labors, as well as giving them their direction. the navigation of the ocean was increasing every year in importance, chiefly through the growth of the american colonies and the taste for the rich products of india. the art of navigation was still imperfect. in order that the captain of a ship at sea may know precisely where he is, he must know two things: how far he is from the equator, and how far he is from a certain known place, say greenwich, paris, washington. being sure of those two things, he can take his chart and mark upon it the precise spot where his ship is at a given moment. then he knows how to steer, and all else that he needs to know in order to pursue his course with confidence. when john harrison was a young man, the art of navigation had so far advanced that the distance from the equator, or the latitude, could be ascertained with certainty by observation of the heavenly bodies. one great difficulty remained to be overcome--the finding of the longitude. this was done imperfectly by means of a watch which kept greenwich time as near as possible. every fine day the captain could ascertain by an observation of the sun just when it was twelve o'clock. if, on looking at this chronometer, he found that by greenwich time it was quarter past two, he could at once ascertain his distance from greenwich, or in other words, his longitude. but the terrible question was, how near right is the chronometer? a variation of a very few minutes would make a difference of more than a hundred miles. to this day, no perfect time-keeper has ever been made. from an early period, the governments of commercial nations were solicitous to find a way of determining the longitude that would be sufficiently correct. thus, the king of spain, in , offered a reward of a thousand crowns to any one who should discover an approximately correct method. soon after, the government of holland offered ten thousand florins. in the english government took hold of the matter, and offered a series of dazzling prizes: five thousand pounds for a chronometer that would enable a ship six months from home to get her longitude within sixty miles; seven thousand five hundred pounds, if within forty miles; ten thousand pounds if within thirty miles. another clause of the bill offered a premium of twenty thousand pounds for the invention of any method whatever, by means of which the longitude could be determined within thirty miles. the bill appears to have been drawn somewhat carelessly; but the substance of it was sufficiently plain, namely, that the british government was ready to make the fortune of any man who should enable navigators to make their way across the ocean in a straight line to their desired port. two years after, the regent of france offered a prize of a hundred thousand francs for the same object. all the world went to watch-making. john harrison, stimulated by these offers to increased exertion, in the year presented himself at greenwich with one of his wonderful clocks, provided with the gridiron pendulum, which he exhibited and explained to the commissioners. perceiving the merit and beauty of his invention, they placed the clock on board a ship bound for lisbon. this was subjecting a pendulum clock to a very unfair trial; but it corrected the ship's reckoning several miles. the commissioners now urged him to compete for the chronometer prize, and in order to enable him to do so they supplied him with money, from time to time, for twenty-four years. at length he produced his chronometer, about four inches in diameter, and so mounted as not to share the motion of the vessel. in , when he was sixty-eight years of age, he wrote to the commissioners that he had completed a chronometer for trial, and requested them to test it on a voyage to the west indies, under the care of his son william. his requests were granted. the success of the chronometer was wonderful. on arriving at jamaica, the chronometer varied but four seconds from greenwich time, and on returning to england the entire variation was a little short of two minutes; which was equivalent to a longitudinal variation of eighteen miles. the ship had been absent from portsmouth one hundred and forty-seven days. this signal triumph was won after forty years of labor and experiment. the commissioners demanding another trial, the watch was taken to barbadoes, and, after an absence of a hundred and fifty-six days, showed a variation of only fifteen seconds. after other and very exacting tests, it was decided that john harrison had fulfilled all the prescribed conditions, and he received accordingly the whole sum of twenty thousand pounds sterling. it is now asserted by experts that he owed the success of his watch, not so much to originality of invention, as to the exquisite skill and precision of his workmanship. he had one of the most perfect mechanical hands that ever existed. it was the touch of a raphael applied to mechanism. john harrison lived to the good old age of eighty-three years. he died in london in , about the time when general washington was getting ready to drive the english troops and their tory friends out of boston. it is not uncommon nowadays for a ship to be out four or five months, and to hit her port so exactly as to sail straight into it without altering her course more than a point or two. peter faneuil, and the great hall he built. a story is told of the late ralph waldo emerson's first lecture, in cincinnati, forty years ago. a worthy pork-packer, who was observed to listen with close attention to the enigmatic utterances of the sage, was asked by one of his friends what he thought of the performance. "i liked it very well," said he, "and i'm glad i went, because i learned from it how the boston people pronounce faneuil hall." he was perhaps mistaken, for it is hardly probable that mr. emerson gave the name in the old-fashioned boston style, which was a good deal like the word _funnel_. the story, however, may serve to show what a widespread and intense reputation the building has. of all the objects in boston it is probably the one best known to the people of the united states, and the one surest to be visited by the stranger. the hall is a curious, quaint little interior, with its high galleries, and its collection of busts and pictures of revolutionary heroes. peter faneuil little thought what he was doing when he built it, though he appears to have been a man of liberal and enlightened mind. the faneuils were prosperous merchants in the french city of rochelle in , when louis xiv. revoked the edict of nantes. the great-grandfather of john jay was also in large business there at that time, and so were the ancestors of our delanceys, badeaus, pells, secors, allaires, and other families familiar to the ears of new yorkers, many of them having distinguished living representatives among us. they were of the religion "called reformed," as the king of france contemptuously styled it. reformed or not, they were among the most intelligent, enterprising, and wealthy of the merchants of rochelle. how little we can conceive the effect upon their minds of the order which came from paris in october, , which was intended to put an end forever to the protestant religion in france. the king meant to make thorough work of it. he ordered all the huguenot churches in the kingdom to be instantly demolished. he forbade the dissenters to assemble either in a building or out of doors, on pain of death and confiscation of all their goods. their clergymen were required to leave the kingdom within fifteen days. their schools were interdicted, and all children hereafter born of protestant parents were to be baptized by the catholic clergymen, and reared as catholics. these orders were enforced with reckless ferocity, particularly in the remoter provinces and cities of the kingdom. the faneuils, the jays, and the delanceys of that renowned city saw their house of worship leveled with the ground. dragoons were quartered in their houses, whom they were obliged to maintain, and to whose insolence they were obliged to submit, for the troops were given to understand that they were the king's enemies and had no rights which royal soldiers were bound to respect. at the same time, the edict forbade them to depart from the kingdom, and particular precautions were taken to prevent men of capital from doing so. john jay records that the ancestor of his family made his escape by artifice, and succeeded in taking with him a portion of his property. such was also the good fortune of the brothers faneuil, who were part of the numerous company from old rochelle who emigrated to new york about , and formed a settlement upon long island sound, twelve miles from new york, which they named, and which is still called, new rochelle. the old names can still be read in that region, both in the churchyards and upon the door plates, and the village of pelham recalls the name of the pell family who fled from rochelle about the same time, and obtained a grant of six thousand acres of land near by. the newcomers were warmly welcomed, as their friends and relations were in england. the faneuil brothers did not remain long in new rochelle, but removed to boston in . benjamin and andrew were their names. there are many traces of them in the early records, indicating that they were merchants of large capital and extensive business for that day. there are evidences also that they were men of intelligence and public spirit. they appear to have been members of the church of england in boston, which of itself placed them somewhat apart from the majority of their fellow-citizens. peter faneuil, the builder of the famous hall, who was born in boston about , the oldest of eleven children, succeeded to the business founded by his uncle andrew, and while still a young man had greatly increased it, and was reckoned one of the leading citizens. a curious controversy had agitated the people of boston for many years. the town had existed for nearly a century without having a public market of any kind, the country people bringing in their produce and selling it from door to door. in february, , occurred the great snow, which destroyed great numbers of domestic and wild animals, and caused provisions for some weeks to be scarce and dear. the inhabitants laid the blame of the dearness to the rapacity of the hucksters, and the subject being brought up in town meeting, a committee reported that the true remedy was to build a market, to appoint market days, and establish rules. the farmers opposed the scheme, as did also many of the citizens. the project being defeated, it was revived year after year, but the country people always contrived to defeat it. an old chronicler has a quaint passage on the subject. "the country people," he says, "always opposed the market, so that the question could not be settled. the reason they give for it is, that if market days were appointed, all the country people coming in at the same time would glut it, and the towns-people would buy their provisions for what they pleased; so rather choose to send them as they think fit. and sometimes a tall fellow brings in a turkey or goose to sell, and will travel through the whole town to see who will give most for it, and it is at last sold for three and six pence or four shillings; and if he had stayed at home, he could have earned a crown by his labor, which is the customary price for a day's work. so any one may judge of the stupidity of the country people." in boston libraries, pamphlets are still preserved on this burning question of a market, which required seventeen years of discussion before a town meeting was brought to vote for the erection of market houses. in , seven hundred pounds were appropriated for the purpose. the market hours were fixed from sunrise to p. m., and a bell was ordered to be rung to announce the time of opening. the country people, however, had their way, notwithstanding. they so resolutely refrained from attending the markets that in less than four years the houses fell into complete disuse. one of the buildings was taken down, and the timber used in constructing a workhouse; one was turned into stores, and the third was torn to pieces by a mob, who carried off the material for their own use. nevertheless, the market question could not be allayed, for the respectable inhabitants of the town were still convinced of the need of a market as a defense against exorbitant charges. for some years the subject was brought up in town meetings; but as often as it came to the point of appropriating money the motion was lost. at length mr. peter faneuil came forward to end the dissension in a truly magnificent manner. he offered to build a market house at his own expense, and make a present of it to the town. even this liberal offer did not silence opposition. a petition was presented to the town meeting, signed by three hundred and forty inhabitants, asking the acceptance of peter faneuil's proposal. the opposition to it, however, was strong. at length it was agreed that, if a market house were built, the country people should be at liberty to sell their produce from door to door if they pleased. even with this concession, only citizens voted for the market and voted against it. thus, by a majority of seven, the people of boston voted to accept the most munificent gift the town had received since it was founded. peter faneuil went beyond his promise. besides building an ample market place, he added a second story for a town hall, and other offices for public use. the building originally measured one hundred feet by forty, and was finished in so elegant a style as to be reckoned the chief ornament of the town. it was completed in , after two years had been spent in building it. it had scarcely been opened for public use when peter faneuil died, aged a little less than forty-three years. the grateful citizens gave him a public funeral, and the selectmen appointed mr. john lovell, schoolmaster, to deliver his funeral oration in the hall bearing his name. the oration was entered at length upon the records of the town, and has been frequently published. in the hall was destroyed by fire. it was immediately rebuilt, and this second structure was the faneuil hall in which were held the meetings preceding and during the war for independence, which have given it such universal celebrity. here samuel adams spoke. here the feeling was created which made massachusetts the centre and source of the revolutionary movement. let me not omit to state that those obstinate country people, who knew what they wanted, were proof against the attractions of faneuil hall market. they availed themselves of their privilege of selling their produce from door to door, as they had done from the beginning of the colony. fewer and fewer hucksters kept stalls in the market, and in a few years the lower room was closed altogether. the building served, however, as town hall until it was superseded by structures more in harmony with modern needs and tastes. what thrilling scenes the hall has witnessed! that is a pleasing touch in one of the letters of john adams to thomas jefferson, where he alludes to what was probably his last visit to the scene of his youthful glory, faneuil hall. mr. adams was eighty-three years old at the time, and it was the artist trumbull, also an old man, who prevailed upon him to go to the hall. "trumbull," he wrote, "with a band of associates, drew me by the cords of old friendship to see his picture, on saturday, where i got a great cold. the air of faneuil is changed. _i have not been used to catch cold there._" no, indeed. if the process of storing electricity had been applied to the interior of this electric edifice, enough of the fluid could have been saved to illuminate boston every fourth of july. it is hard to conceive of a tranquil or commonplace meeting there, so associated is it in our minds with outbursts of passionate feeling. speaking of john adams calls to mind an anecdote related recently by a venerable clergyman of new york, rev. william hague. mr. hague officiated as chaplain at the celebration of the fourth of july in boston, in , when charles francis adams delivered the oration in faneuil hall, which was his first appearance on a public platform. while the procession was forming to march to the hall, ex-president john quincy adams entered into conversation with the chaplain, during which he spoke as follows:-- "this is one of the happiest days of my whole life. fifty years expire to-day since i performed in boston my first public service, which was the delivery of an oration to celebrate our national independence. after half a century of active life, i am spared by a benign providence to witness my son's performance of his first public service, to deliver an oration in honor of the same great event." the chaplain replied to mr. adams:-- "president, i am well aware of the notable connection of events to which you refer; and having committed and declaimed a part of your own great oration when a schoolboy in new york, i could without effort repeat it to you now." the aged statesman was surprised and gratified at this statement. the procession was formed and the oration successfully delivered. since that time, i believe, an adams of the fourth generation has spoken in the same place, and probably some readers will live to hear one of the fifth and sixth. the venerable john adams might well say that he had not been used to catch cold in the air of faneuil hall, for as far as i know there has never been held there a meeting which has not something of extraordinary warmth in its character. i have mentioned above that the first public meeting ever held in it after its completion in was to commemorate the premature death of the donor of the edifice; on which occasion mr. john lovell delivered a glowing eulogium. "let this stately edifice which bears his name," cried the orator, "witness for him what sums he expended in public munificence. this building, erected by him, at his own immense charge, for the convenience and ornament of the town, is incomparably the greatest benefaction ever yet known to our western shore." towards the close of his speech, the eloquent schoolmaster gave utterance to a sentiment which has often since been repeated within those walls. "may this hall be ever sacred to the interests of truth, of justice, of loyalty, of honor, of liberty. may no private views nor party broils ever enter these walls." whether this wish has been fulfilled or not is a matter of opinion. general gage doubtless thought that it had not been. scenes of peculiar interest took place in the hall about the beginning of the year , when the news was received in boston that king george ii. had fallen dead in his palace at kensington, and that george iii., his grandson, had been proclaimed king. it required just two months for this intelligence to cross the ocean. the first thing in order, it seems, was to celebrate the accession of the young king. he was proclaimed from the balcony of the town house; guns were fired from all the forts in the harbor; and in the afternoon a grand dinner was given in faneuil hall. these events occurred on the last day but one of the year . the first day of the new year, , was ushered in by the solemn tolling of the church bells in the town, and the firing of minute guns on castle island. these mournful sounds were heard all day, even to the setting of the sun. however doleful the day may have seemed, there was more appropriateness in these signs of mourning than any man of that generation could have known; for with george ii. died the indolent but salutary let-them-alone policy under which the colonies enjoyed prosperity and peace. with the accession of the new king the troubles began which ended in the disruption of the empire. george iii. was the last king whose accession received official recognition in the thirteen colonies. i have hunted in vain through my books to find some record of the dinner given in faneuil hall to celebrate the beginning of the new reign. it would be interesting to know how the sedate people of boston comported themselves on a festive occasion of that character. john adams was a young barrister then. if the after-dinner speeches were as outspoken as the political comments he entered in his diary, the proceedings could not have been very acceptable to the royal governor. mr. adams was far from thinking that england had issued victorious from the late campaigns, and he thought that france was then by far the most brilliant and powerful nation in europe. a few days after these loyal ceremonies, boston experienced what is now known there as a "cold snap," and it was so severe as almost to close the harbor with ice. one evening, in the midst of it, a fire broke out opposite faneuil hall. such was the extremity of cold that the water forced from the engines fell upon the ground in particles of ice. the fire swept across the street and caught faneuil hall, the interior of which was entirely consumed, nothing remaining but the solid brick walls. it was rebuilt in just two years, and reopened in the midst of another remarkably cold time, which was signalized by another bad fire. there was so much distress among the poor that winter that a meeting was held in faneuil hall for their relief, rev. samuel mather preaching a sermon on the occasion, and this was the first discourse delivered in it after it was rebuilt. seven years later the hall was put to a very different use. a powerful fleet of twelve men-of-war, filled with troops, was coming across the ocean to apply military pressure to the friends of liberty. a convention was held in faneuil hall, attended by delegates from the surrounding towns, as well as by the citizens of boston. the people were in consternation, for they feared that any attempt to land the troops would lead to violent resistance. the convention indeed requested the inhabitants to "provide themselves with firearms, that they may be prepared in case of sudden danger." the atmosphere was extremely electric in boston just then. the governor sent word to the convention assembled in faneuil hall that their meeting was "a very high offense" which only their ignorance of the law could excuse; but the plea of ignorance could no longer avail them, and he commanded them to disperse. the convention sent a reply to the governor, which he refused to receive, and they continued in session until the fleet entered the harbor. october , , the twelve british men-of-war were anchored in a semicircle opposite the town, with cannon loaded, and cleared for action, as though boston were a hostile stronghold, instead of a defenseless country town of loyal and innocent fellow-citizens. two regiments landed; one of which encamped on the common, and the other marched to faneuil hall, where they were quartered for four or five weeks. with one accord the merchants and property-owners refused to let any building for the use of the troops. boston people to this day chuckle over the mishap of the sheriff who tried to get possession of a large warehouse through a secret aperture in the cellar wall. he did succeed in effecting an entrance, with several of his deputies. but as soon as they were inside the building, the patriots outside closed the hole; and thus, instead of getting possession of the building, the loyal officers found themselves prisoners in a dark cellar. they were there for several hours before they could get word to the commanding officer, who released them. the joke was consolatory to the inhabitants. it was on this occasion that rev. mather byles heightened the general merriment by his celebrated jest on the british soldiers: "the people," said he, "sent over to england to obtain a redress of grievances. the grievances have returned _red-dressed_." the hall is still used for public meetings, and the region roundabout is still an important public market. [illustration: chauncey jerome] chauncey jerome, yankee clock-maker. poor boys had a hard time of it in new england eighty years ago. observe, now, how it fared with chauncey jerome,--he who founded a celebrated clock business in connecticut, that turned out six hundred clocks a day, and sent them to foreign countries by the ship-load. but do not run away with the idea that it was the hardship and loneliness of his boyhood that "made a man of him." on the contrary, they injured, narrowed, and saddened him. he would have been twice the man he was, and happier all his days, if he had passed an easier and a more cheerful childhood. it is not good for boys to live as he lived, and work as he worked, during the period of growth, and i am glad that fewer boys are now compelled to bear such a lot as his. his father was a blacksmith and nailmaker, of plymouth, connecticut, with a houseful of hungry boys and girls; and, consequently, as soon as chauncey could handle a hoe or tie up a bundle of grain he was kept at work on the farm; for, in those days, almost all mechanics in new england cultivated land in the summer time. the boy went to school during the three winter months, until he was ten years old; then his school-days and play-days were over forever, and his father took him into the shop to help make nails. even as a child he showed that power of keeping on, to which he owed his after-success. there was a great lazy boy at the district school he attended who had a load of wood to chop, which he hated to do, and this small chauncey, eight or nine years of age, chopped the whole of it for him for _one cent_! often he would chop wood for the neighbors in moonlight evenings for a few cents a load. it is evident that the quality which made him a successful man of business was not developed by hardship, for he performed these labors voluntarily. he was naturally industrious and persevering. when he was eleven years of age his father suddenly died, and he found himself obliged to leave his happy home and find farm work as a poor hireling boy. there were few farmers then in connecticut--nay, there were few people anywhere in the world--who knew how to treat an orphan obliged to work for his subsistence among strangers. on a monday morning, with his little bundle of clothes in his hand, and an almost bursting heart, he bade his mother and his brothers and sisters good-by, and walked to the place which he had found for himself, on a farm a few miles from home. he was most willing to work; but his affectionate heart was starved at his new place; and scarcely a day passed during his first year when he did not burst into tears as he worked alone in the fields, thinking of the father he had lost, and of the happy family broken up never to live together again. it was a lonely farm, and the people with whom he lived took no interest in him as a human being, but regarded him with little more consideration than one of their other working animals. they took care, however, to keep him steadily at work, early and late, hot and cold, rain and shine. often he worked all day in the woods chopping down trees with his shoes full of snow; he never had a pair of boots till he was nearly twenty-one years of age. once in two weeks he had a great joy; for his master let him go to church every other sunday. after working two weeks without seeing more than half a dozen people, it gave him a peculiar and intense delight just to sit in the church gallery and look down upon so many human beings. it was the only alleviation of his dismal lot. poor little lonely wretch! one day, when he was thirteen years of age, there occurred a total eclipse of the sun, a phenomenon of which he had scarcely heard, and he had not the least idea what it could be. he was hoeing corn that day in a solitary place. when the darkness and the chill of the eclipse fell upon the earth, feeling sure the day of judgment had come, he was terrified beyond description. he watched the sun disappearing with the deepest apprehension, and felt no relief until it shone out bright and warm as before. it seems strange that people in a christian country could have had a good steady boy like this in their house and yet do nothing to cheer or comfort his life. old men tell me it was a very common case in new england seventy years ago. this hard experience on the farm lasted until he was old enough to be apprenticed. at fourteen he was bound to a carpenter for seven years, during which he was to receive for his services his board and his clothes. already he had done almost the work of a man on the farm, being a stout, handy fellow, and in the course of two or three years he did the work of a full-grown carpenter; nevertheless, he received no wages except the necessaries of life. fortunately the carpenter's family were human beings, and he had a pleasant, friendly home during his apprenticeship. even under the gentlest masters apprentices, in old times, were kept most strictly to their duty. they were lucky if they got the whole of thanksgiving and the fourth of july for holidays. now, this apprentice, when he was sixteen, was so homesick on a certain occasion that he felt he _must_ go and see his mother, who lived near her old home, twenty miles from where he was working on a job. he walked the distance in the night, in order not to rob his master of any of the time due to him. it was a terrible night's work. he was sorry he had undertaken it; but having started he could not bear to give it up. half the way was through the woods, and every noise he heard he thought was a wild beast coming to kill him, and even the piercing notes of the whippoorwill made his hair stand on end. when he passed a house the dogs were after him in full cry, and he spent the whole night in terror. let us hope the caresses of his mother compensated him for this suffering. the next year when his master had a job thirty miles distant, he frequently walked the distance on a hot summer's day, with his carpenter's tools upon his back. at that time light vehicles, or any kind of one-horse carriage, were very rarely kept in country places, and mechanics generally had to trudge to their place of work, carrying their tools with them. so passed the first years of his apprenticeship. all this time he was thinking of quite another business,--that of clock-making,--which had been developed during his childhood near his father's house, by eli terry, the founder of the yankee wooden-clock manufacture. this ingenious mr. terry, with a small saw and a jack-knife, would cut out the wheels and works for twenty-five clocks during the winter, and, when the spring opened, he would sling three or four of them across the back of a horse, and keep going till he sold them, for about twenty-five dollars apiece. this was for the works only. when a farmer had bought the machinery of a clock for twenty-five dollars, he employed the village carpenter to make a case for it, which might cost ten or fifteen dollars more. it was in this simple way that the country was supplied with those tall, old-fashioned clocks, of which almost every ancient farm-house still contains a specimen. the clock-case was sometimes built into the house like a pillar, and helped to support the upper story. some of them were made by very clumsy workmen, out of the commonest timber, just planed in the roughest way, and contained wood enough for a pretty good-sized organ. the clock business had fascinated chauncey jerome from his childhood, and he longed to work at it. his guardian dissuaded him. so many clocks were then making, he said, that in two or three years the whole country would be supplied, and then there would be no more business for a maker. this was the general opinion. at a training, one day, the boy overheard a group talking of eli terry's _folly_ in undertaking to make two hundred clocks all at once. "he'll never live long enough to finish them," said one. "if he should," said another, "he could not possibly sell so many. the very idea is ridiculous." the boy was not convinced by these wise men of the east, and he lived to make and to sell two hundred thousand clocks in one year! when his apprenticeship was a little more than half over, he told his master that if he would give him four months in the winter of each year, when business was dull, he would buy his own clothes. his master consenting, he went to waterbury, connecticut, and began to work making clock dials, and very soon got an insight into the art and mystery of clock-making. the clock-makers of that day, who carried round their clock-movements upon a horse's back, often found it difficult to sell them in remote country places, because there was no carpenter near by competent to make a case. two smart yankees hired our apprentice to go with them to the distant state of new jersey, for the express purpose of making cases for the clocks they sold. on this journey he first saw the city of new york. he was perfectly astonished at the bustle and confusion. he stood on the corner of chatham and pearl streets for more than an hour, wondering why so many people were hurrying about so in every direction. "what is going on?" said he, to a passer-by. "what's the excitement about?" the man hurried on without noticing him; which led him to conclude that city people were not over polite. the workmen were just finishing the interior of the city hall, and he was greatly puzzled to understand how those winding stone stairs could be fixed without any visible means of support. in new jersey he found another wonder. the people there kept christmas more strictly than sunday; a thing very strange to a child of the puritans, who hardly knew what christmas was. every winter added something to his knowledge of clock-making, and, soon after he was out of his apprenticeship, he bought some portions of clocks, a little mahogany, and began to put clocks together on his own account, with encouraging success from the beginning. it was a great day with him when he received his first magnificent order from a southern merchant for twelve wooden clocks at twelve dollars apiece! when they were done, he delivered them himself to his customer, and found it impossible to believe that he should actually receive so vast a sum as a hundred and forty-four dollars. he took the money with a trembling hand, and buttoned it up in his pocket. then he felt an awful apprehension that some robbers might have heard of his expecting to receive this enormous amount, and would waylay him on the road home. he worked but too steadily. he used to say that he loved to work as well as he did to eat, and that sometimes he would not go outside of his gate from one sunday to the next. he soon began to make inventions and improvements. his business rapidly increased, though occasionally he had heavy losses and misfortunes. his most important contribution to the business of clock-making was his substitution of brass for wood in the cheap clocks. he found that his wooden clocks, when they were transported by sea, were often spoiled by the swelling of the wooden wheels. one night, in a moment of extreme depression during the panic of , the thought darted into his mind,-- "a cheap clock can be made of brass as well as wood!" it kept him awake nearly all night. he began at once to carry out the idea. it gave an immense development to the business, because brass clocks could be exported to all parts of the world, and the cost of making them was greatly lessened by new machinery. it was chauncey jerome who learned how to make a pretty good brass clock for forty cents, and a good one for two dollars; and it was he who began their exportation to foreign lands. clocks of his making ticked during his lifetime at jerusalem, saint helena, calcutta, honolulu, and most of the other ends of the earth. after making millions of clocks, and acquiring a large fortune, he retired from active business, leaving his splendid manufactory at new haven to the management of others. they thought they knew more than the old man; they mismanaged the business terribly, and involved him in their own ruin. he was obliged to leave his beautiful home at seventy years of age, and seek employment at weekly wages--he who had given employment to three hundred men at once. he scorned to be dependent. i saw and talked long with this good old man when he was working upon a salary, at the age of seventy-three, as superintendent of a large clock factory in chicago. he did not pretend to be indifferent to the change in his position. he felt it acutely. he was proud of the splendid business he had created, and he lamented its destruction. he said it was one of his consolations to know that, in the course of his long life, he had never brought upon others the pains he was then enduring. he bore his misfortunes as a man should, and enjoyed the confidence and esteem of his new associates. captain pierre laclede liguest, pioneer. the bridge which springs so lightly and so gracefully over the mississippi at st. louis is a truly wonderful structure. it often happens in this world that the work which is done best conceals the merit of the worker. all is finished so thoroughly and smoothly, and fulfills its purpose with so little jar and friction, that the difficulties overcome by the engineer become almost incredible. no one would suppose, while looking down upon the three steel arches of this exquisite bridge, that its foundations are one hundred and twenty feet below the surface of the water, and that its construction cost nine millions of dollars and six years of time. its great height above the river is also completely concealed by the breadth of its span. the largest steamboat on the river passes under it at the highest stage of water, and yet the curve of the arches appears to have been selected merely for its pictorial effect. it is indeed a noble and admirable work, an honor to the city and country, and, above all, to captain james b. eads, who designed and constructed it. the spectator who sees for the first time st. louis, now covering as far as the eye can reach the great bend of the river on which it is built, the shore fringed with steamboats puffing black smoke, and the city glittering in the morning sun, beholds one of the most striking and animating spectacles which this continent affords. go back one hundred and twenty years. that bend was then covered with the primeval forest, and the only object upon it which betrayed the hand of man was a huge green mound, a hundred feet high, that had been thrown up ages before by some tribe which inhabited the spot before our indians had appeared. all that region swarmed with fur-bearing animals, deer, bear, buffalo, and beaver. it is difficult to see how this continent ever could have been settled but for the fur trade. it was beaver skin which enabled the pilgrim fathers of new england to hold their own during the first fifty years of their settlement. it was in quest of furs that the pioneers pushed westward, and it was by the sale of furs that the frontier settlers were at first supplied with arms, ammunition, tools, and salt. the fur trade also led to the founding of st. louis. in the year a great fleet of heavy batteaux, loaded with the rude merchandise needed by trappers and indians, approached the spot on which st. louis stands. this fleet had made its way up the mississippi with enormous difficulty and toil from new orleans, and only reached the mouth of the missouri at the end of the fourth month. it was commanded by pierre laclede liguest, the chief partner in a company chartered to trade with the indians of the missouri river. he was a frenchman, a man of great energy and executive force, and his company of hunters, trappers, mechanics, and farmers, were also french. on his way up the river captain liguest had noticed this superb bend of land, high enough above the water to avoid the floods, and its surface only undulating enough for the purposes of a settlement. having reached the mouth of the muddy river (as they called the missouri) in the month of december, and finding no place there well suited to his purpose, he dropped down the stream seventeen miles, and drove the prows of his boats into what is now the levee of st. louis. it was too late in the season to begin a settlement. but he "blazed" the trees to mark the spot, and he said to a young man of his company, auguste chouteau:-- "you will come here as soon as the river is free from ice, and will cause this place to be cleared, and form a settlement according to the plan i shall give you." the fleet fell down the river to the nearest french settlement, fort de chartres. captain liguest said to the commander of this fort on arriving:-- "i have found a situation where i intend to establish a settlement which in the future will become one of the most beautiful cities in america." these are not imaginary words. auguste chouteau, who was selected to form the settlement, kept a diary, part of which is now preserved in the mercantile library at st. louis, and in it this saying of captain liguest is recorded. so, the next spring he dispatched young chouteau with a select body of thirty mechanics and hunters to the site of the proposed settlement. "you will go," said he, "and disembark at the place where we marked the trees. you will begin to clear the place and build a large shed to contain the provisions and tools and some little cabins to lodge the men." on the fifteenth of february, , the party arrived, and the next morning began to build their shed. liguest named the settlement st. louis, in honor of the patron saint of the royal house of france--louis xv. being then upon the throne. all went well with the settlement, and it soon became the seat of the fur trade for an immense region of country, extending gradually from the mississippi to the rocky mountains. the french lived more peacefully with the indians than any other people who assisted to settle this continent, and the reason appears to have been that they became almost indian themselves. they built their huts in the wigwam fashion, with poles stuck in the ground. they imitated the ways and customs of the indians, both in living and in hunting. they went on hunting expeditions with indians, wore the same garments, and learned to live on meat only, as indian hunting parties generally did. but the circumstance which most endeared the french to the indians was their marrying the daughters of the chiefs, which made the indians regard them as belonging to their tribe. besides this, they accommodated themselves to the indian character, and learned how to please them. a st. louis fur trader, who was living a few years ago in the ninetieth year of his age, used to speak of the ease with which an influential chief could be conciliated. "i could always," said he, "make the principal chief of a tribe my friend by a piece of vermilion, a pocket looking-glass, some flashy-looking beads, and a knife. these things made him a puppet in my hands." even if a valuable horse had been stolen, a chief, whose friendship had been won in this manner, would continue to scold the tribe until the horse was brought back. the indians, too, were delighted with the frenchman's fiddle, his dancing, his gayety of manner, and even with the bright pageantry of his religion. it was when the settlement was six years old that the inhabitants of st. louis, a very few hundreds in number, gathered to take part in the consecration of a little church, made very much like the great council wigwam of the indians, the logs being placed upright, and the interstices filled with mortar. this church stood near the river, almost on the very site of the present cathedral. mass was said, and the te deum was chanted. at the first laying out of the village, captain liguest set apart the whole block as a site for the church, and it remains church property to this day. it is evident from chouteau's diary that pierre laclede liguest, though he had able and energetic assistants, was the soul of the enterprise, and the real founder of st. louis. he was one of that stock of frenchmen who put the imprint of their nation, never to be effaced, upon the map of north america--a kind of frenchman unspeakably different from those who figured in the comic opera and the masquerade ball of the late corrupt and effeminating empire. he was a genial and generous man, who rewarded his followers bountifully, and took the lead in every service of difficulty and danger. while on a visit to new orleans he died of one of the diseases of the country, and was buried on the shore near the mouth of the arkansas river. his executor and chief assistant, auguste chouteau, born at new orleans in , lived one hundred years, not dying till . there are many people in st. louis who remember him. a very remarkable coincidence was, that his brother, pierre chouteau, born in new orleans in , died in st. louis in , having also lived just one hundred years. both of these brothers were identified with st. louis from the beginning, where they lived in affluence and honor for seventy years, and where their descendants still reside. the growth of st. louis was long retarded by the narrowness and tyranny of the spanish government, to which the french ceded the country about the time when st. louis was settled. but in it was transferred to the united states, and from that time its progress has been rapid and almost uninterrupted. when president jefferson's agent took possession, there was no post-office, no ferry over the river, no newspaper, no hotel, no protestant church, and no school. nor could any one hold land who was not a catholic. instantly, and as a matter of course, all restricting laws were swept away; and before two years had passed there was a ferry, a post-office, a newspaper, a protestant church, a hotel, and two schools, one french and one english. israel putnam. it is strange that so straightforward and transparent a character as "old put" should have become the subject of controversy. too much is claimed for him by some disputants, and much too little is conceded to him by others. he was certainly as far from being a rustic booby as he was from being a great general. conceive him, first, as a thriving, vigorous, enterprising connecticut farmer, thirty years of age, cultivating with great success his own farm of five hundred and fourteen acres, all paid for. himself one of a family of twelve children, and belonging to a prolific race which has scattered putnams all over the united states, besides leaving an extraordinary number in new england, he had married young at his native salem, and established himself soon after in the northeastern corner of connecticut. at that period, , connecticut was to massachusetts what colorado is to new york at present; and thither, accordingly, this vigorous young man and his young wife early removed, and hewed out a farm from the primeval woods. he was just the man for a pioneer. his strength of body was extraordinary, and he had a power of sustained exertion more valuable even than great strength. nothing is more certain than that he was an enterprising and successful farmer, who introduced new fruits, better breeds of cattle, and improved implements. there is still to be seen on his farm a long avenue of ancient apple trees, which, the old men of the neighborhood affirm, were set out by israel putnam one hundred and forty years ago. the well which he dug is still used. coming to the place with considerable property inherited from his father (for the putnams were a thriving race from the beginning), it is not surprising that he should have become one of the leading farmers in a county of farmers. at the same time he was not a studious man, and had no taste for intellectual enjoyments. he was not then a member of the church. he never served upon the school committee. there was a library association at the next village, but he did not belong to it. for bold riding, skillful hunting, wood-chopping, hay-tossing, ploughing, it was hard to find his equal; but, in the matter of learning, he could write legibly, read well enough, spell in an independent manner, and not much more. with regard to the wolf story, which rests upon tradition only, it is not improbable, and there is no good reason to doubt it. similar deeds have been done by brave backwoodsmen from the beginning, and are still done within the boundaries of the united states every year. the story goes, that when he had been about two years on his new farm, the report was brought in one morning that a noted she-wolf of the neighborhood had killed seventy of his sheep and goats, besides wounding many lambs and kids. this wolf, the last of her race in that region, had long eluded the skill of every hunter. upon seeing the slaughter of his flock, the young farmer, it appears, entered into a compact with five of his neighbors to hunt the pernicious creature by turns until they had killed her. the animal was at length tracked to her den, a cave extending deep into a rocky hill. the tradition is, that putnam, with a rope around his body, a torch in one hand, and rifle in the other, went twice into the cave, and the second time shot the wolf dead, and was drawn out by the people, wolf and all. an exploit of this nature gave great celebrity in an outlying county in the year . meanwhile he continued to thrive, and one of the old-fashioned new england families of ten children gathered about him. as they grew towards maturity, he bought a share in the library association, built a pew for his family in the church, and comported himself in all ways as became a prosperous farmer and father of a numerous family. so passed his life until he reached the age of thirty-seven, when he already had a boy fifteen years of age, and was rich in all the wealth which connecticut then possessed. the french war broke out--the war which decided the question whether the french or the english race should possess north america. his reputation was such that the legislature of connecticut appointed him at once a captain, and he had no difficulty in enlisting a company of the young men of his county, young farmers or the sons of farmers. he gained great note as a scouter and ranger, rendering such important service in this way to the army that the legislature made him a special grant of "fifty spanish milled dollars" as an honorable gift. he was famous also for yankee ingenuity. a colonial newspaper relates an anecdote illustrative of this. the british general was sorely perplexed by the presence of a french man-of-war commanding a piece of water which it was necessary for him to cross. "general," said putnam, "that ship must be taken." "aye," replied the general, "i would give the world if she was taken." "i will take her," said putnam. "how?" asked the general. "give me some wedges, a beetle, and a few men of my own choice." when night came, putnam rowed under the vessel's stern, and drove the wedges between the rudder and the ship. in the morning she was seen with her sails flapping helplessly in the middle of the lake, and she was soon after blown ashore and captured. among other adventures, putnam was taken prisoner by the indians, and carried to his grave great scars of the wounds inflicted by the savages. he served to the very end of the war, pursuing the enemy even into the tropics, and assisting at the capture of havana. he returned home, after nine years of almost continuous service, with the rank of colonel, and such a reputation as made him the hero of connecticut, as washington was the hero of virginia at the close of the same war. at any time of public danger requiring a resort to arms, he would be naturally looked to by the people of connecticut to take the command. eleven peaceful years he now spent at home. his wife died, leaving an infant a year old. he joined the church; he married again; he cultivated his farm; he told his war stories. the stamp act excitement occurred in , when putnam joined the sons of liberty, and called upon the governor of the colony as a deputy from them. "what shall i do," asked the governor, "if the stamped paper should be sent to me by the king's authority?" "lock it up," said putnam, "until we visit you again." "and what will you do with it?" "we shall expect you to give us the key of the room where it is deposited; and if you think fit, in order to screen yourself from blame, you may forewarn us upon our peril not to enter the room." "and what will you do afterwards?" "send it safely back again." "but if i should refuse you admission?" "your house will be level with the dust in five minutes." fortunately, the stamped paper never reached connecticut, and the act was repealed soon after. the eventful year, , arrived. putnam was fifty-six years of age, a somewhat portly personage, weighing two hundred pounds, with a round, full countenance, adorned by curly locks, now turning gray--the very picture of a hale, hearty, good-humored, upright and downright country gentleman. news came that the port of boston was closed, its business suspended, its people likely to be in want of food. the farmers of the neighborhood contributed a hundred and twenty-five sheep, which putnam himself drove to boston, sixty miles off, where he had a cordial reception by the people, and was visited by great numbers of them at the house of dr. warren, where he lived. the polite people of boston were delighted with the scarred old hero, and were pleased to tell anecdotes of his homely ways and fervent, honest zeal. he mingled freely, too, with the british officers, who _chaffed_ him, as the modern saying is, about his coming down to boston to fight. they told him that twenty great ships and twenty regiments would come unless the people submitted. "if they come," said putnam, "i am ready to treat them as enemies." one day in the following spring, april twentieth, while he was ploughing in one of his fields with a yoke of oxen driven by his son, daniel, a boy of fifteen, an express reached him giving him the news of the battle of lexington, which had occurred the day before. daniel putnam has left a record of what his father did on this occasion. "he loitered not," wrote daniel, "but left me, the driver of his team, to unyoke it in the furrow, and not many days after to follow him to camp." colonel putnam mounted a horse, and set off instantly to alarm the officers of militia in the neighboring towns. returning home a few hours after, he found hundreds of minute-men assembled, armed and equipped, who had chosen him for their commander. he accepted the command, and, giving them orders to follow, he pushed on without dismounting, rode the same horse all night, and reached cambridge next morning at sunrise, still wearing the checked shirt which he had had on when ploughing in his field. as mr. bancroft remarks, he brought to his country's service an undaunted courage and a devoted heart. his services during the revolution are known to almost every reader. every one seems to have liked him, for he had a very happy turn for humor, sang a good song, and was a very cheerful old gentleman. in , after four years of vigorous and useful service, too arduous for his age, he suffered a paralytic stroke, which obliged him to leave the army. he lived, however, to see his country free and prosperous, surviving to the year , when he died, aged seventy-three. i saw his commission as major-general hanging in the house of one of his grandsons, colonel a. p. putnam, at nashville, some years ago. he has descendants in every state. george flower. pioneer. travelers from old europe are surprised to find in chicago such an institution as an historical society. what can a city of yesterday, they ask, find to place in its archives, beyond the names of the first settlers, and the erection of the first elevator? they forget that the newest settlement of civilized men inherits and possesses the whole past of our race, and that no community has so much need to be instructed by history as one which has little of its own. nor is it amiss for a new commonwealth to record its history as it makes it, and store away the records of its vigorous infancy for the entertainment of its mature age. the first volume issued by the chicago historical society contains an account of what is still called the "english settlement," in edwards county, illinois, founded in by two wealthy english farmers, morris birkbeck and george flower. these gentlemen sold out all their possessions in england, and set out in search of the prairies of the great west, of which they had heard in the old country. they were not quite sure there were any prairies, for all the settled parts of the united states, they knew, had been covered with the dense primeval forest. the existence of the prairies rested upon the tales of travelers. so george flower, in the spring of , set out in advance to verify the story, bearing valuable letters of introduction, one from general la fayette to ex-president jefferson. with plenty of money in his pocket and enjoying every other advantage, he was nearly two years in merely _finding_ the prairies. first, he was fifty days in crossing the ocean, and he spent six weeks in philadelphia, enjoying the hospitality of friends. the fourth month of his journey had nearly elapsed before he had fairly mounted his horse and started on his westward way. it is a pity there is not another new continent to be explored and settled, because the experience gained in america would so much facilitate the work. upon looking over such records as that of george flower's history we frequently meet with devices and expedients of great value in their time and place, but which are destined soon to be numbered among the lost arts. for example, take the mode of saddling and loading a horse for a ride of fifteen hundred miles, say, from the atlantic to the far west, or back again. it was a matter of infinite importance to the rider, for every part of the load was subjected to desperate pulls and wrenches, and the breaking of a strap, at a critical moment in crossing a river or climbing a steep, might precipitate both horse and rider to destruction. on the back of the horse was laid, first of all, a soft and thin blanket, which protected the animal in some degree against the venomous insects that abounded on the prairies, the attacks of which could sometimes madden the gentlest horse. upon this was placed the saddle, which was large, and provided in front with a high pommel, and behind with a pad to receive part of the lading. the saddle was a matter of great importance, as well as its girths and crupper strap, all of which an experienced traveler subjected to most careful examination. every stitch was looked at, and the strength of all the parts repeatedly tested. over the saddle--folded twice, if not three times--was a large, thick, and fine blanket, as good a one as the rider could afford, which was kept in its place by a broad surcingle. on the pad behind the saddle were securely fastened a cloak and umbrella, rolled together as tight as possible and bound with two straps. next we have to consider the saddle bags, stuffed as full as they could hold, each bag being exactly of the same weight and size as the other. as the horseman put into them the few articles of necessity which they would hold he would balance them frequently, to see that one did not outweigh the other even by half a pound. if this were neglected, the bags would slip from one side to the other, graze the horse's leg, and start him off in a "furious kicking gallop." the saddle-bags were slung across the saddle under the blanket, and kept in their place by two loops through which the stirrup leathers passed. so much for the horse. the next thing was for the rider to put on his leggings, which were pieces of cloth about a yard square, folded round the leg from the knee to the ankle, and fastened with pins and bands of tape. these leggings received the mud and water splashed up by the horse, and kept the trousers dry. thus prepared, the rider proceeded to mount, which was by no means an easy matter, considering what was already upon the horse's back. the horse was placed as near as possible to a stump, from which, with a "pretty wide stride and fling of the leg," the rider would spring into his seat. it was so difficult to mount and dismount, that experienced travelers would seldom get off until the party halted for noon, and not again until it was time to camp. women often made the journey on horseback, and bore the fatigue of it about as well as men. instead of a riding-habit, they wore over their ordinary dress a long skirt of dark-colored material, and tied their bonnets on with a large handkerchief over the top, which served to protect the face and ears from the weather. the packing of the saddle made the seat more comfortable, and even safer, for both men and women. the rider, in fact, was seldom thrown unless the whole load came off at once. thus mounted, a party of experienced horsemen and horsewomen would average their thirty miles a day for a month at a time, providing no accident befel them. they were, nevertheless, liable to many accidents and vexatious delays. a horse falling lame would delay the party. occasionally there would be a stampede of all the horses, and days lost in finding them. the greatest difficulty of all was the overflowing waters. no reader can have forgotten the floods in the western country in the spring of , when every brook was a torrent and every river a deluge. imagine a party of travelers making their westward way on horseback at such a time, before there was even a raft ferry on any river west of the alleghanies, and when all the valleys would be covered with water. it was by no means unusual for a party to be detained a month waiting for the waters of a large river to subside, and it was a thing at some seasons of daily occurrence for all of them to be soused up to their necks in water. many of the important fords, too, could only be crossed by people who knew their secret. i received once myself directions for crossing a ford in south carolina something like this: i was told to go straight in four lengths of the horse; then "turn square to the right" and go two lengths; and finally "strike for the shore, slanting a little down the stream." luckily, i had some one with me more expert in fords than i was, and through his friendly guidance managed to flounder through. between new york and baltimore, in , there were more than twenty streams to be forded, and six wide rivers or inlets to be ferried over. we little think, as we glide over these streams now, that the smallest of them, in some seasons, presented difficulties to our grandfathers going southward on horseback. the art of camping out was wonderfully well understood by the early pioneers. women were a great help in making the camp comfortable. as the pilgrim fathers may be said to have discovered the true method of settling the sea-shore, so the western pioneer found the best way of traversing and subduing the interior wilderness. the secret in both cases was to get _the aid of women and children_! they supplied men with motive, did a full half of the labor, and made it next to impossible to turn back. mr. flower makes a remark in connection with this subject, the truth of which will be attested by many. "it is astonishing," he says, "how soon we are restored from fatigue caused by exercise in the open air. debility is of much longer duration from labor in factories, stores, and in rooms warmed by stoves. hail, snow, thunder storms, and drenching rains are all _restoratives_ to health and spirits." often, when the company would be all but tired out by a long day's ride in hot weather, and the line stretched out three or four miles, a good soaking rain would restore their spirits at once. nor did a plunge into the stream, which would wet every fibre of their clothing, do them any harm. they would ride on in the sun, and let their clothes dry in the natural way. it must be owned, however, that some of the winter experiences of travelers in the prairie country were most severe. in the forest a fire can be made and some shelter can be found. but imagine a party on the prairie in the midst of a driving snowstorm, overtaken by night, the temperature at zero. even in these circumstances knowledge was safety. each man would place his saddle on the ground and sit upon it, covering his shoulders and head with his blanket, and holding his horse by the bridle. in this way the human travelers usually derived warmth and shelter enough from the horses to keep them from freezing to death. another method was to tie their horses, spread a blanket on the ground, and sit upon it as close together as they could. sometimes, indeed, a whole party would freeze together in a mass; but commonly all escaped without serious injury, and in some instances invalids were restored to health by exposure which we should imagine would kill a healthy man. when george flower rode westward in , lancaster, pa., was the largest inland town of the united states, and dr. priestley's beautiful abode at sunbury on the susquehanna was still on the outside of the "far west." he had more trouble in getting to pittsburg than he would now have in going round the world. in the alleghany mountains he lost his way, and was rescued by the chance of finding a stray horse which he caught and mounted, and was carried by it to the only cabin in the region. the owner of this cabin was "a poor irishman with a coat so darned, patched, and tattered as to be quite a curiosity." "how i cherished him!" says the traveler. "no angel's visit could have pleased me so well. he pointed out to me the course and showed me into a path." pittsburg was already a smoky town. leaving it soon, he rode on westward to cincinnati, then a place of five or six thousand inhabitants, but growing rapidly. even so far west as cincinnati he could still learn nothing of the prairies. "not a person that i saw," he declares, "knew anything about them. i shrank from the idea of settling in the midst of a wood of heavy timber, to hack and to hew my way to a little farm, ever bounded by a wall of gloomy forest." then he rode across kentucky, where he was struck, as every one was and is, by the luxuriant beauty of the blue-grass farms. he dwells upon the difficulty and horror of fording the rivers at that season of the year. some of his narrow escapes made such a deep impression upon his mind that he used to dream of them fifty years after. he paid a visit to old governor shelby of warlike renown, one of the heroes of the frontier, and there at last he got some news of the prairies! he says: "it was at governor shelby's house (in lincoln county, ky.) that i met the first person who confirmed me in the existence of the prairies." this informant was the governor's brother, who had just come from the mississippi river across the glorious prairies of illinois to the ohio. the information was a great relief. he was sure now that he had left his native land on no fool's errand, the victim of a traveler's lying tale. being thus satisfied that there _were_ prairies which could be found whenever they were wanted, he suspended the pursuit. he had been then seven months from home, and november being at hand, too late to explore an unknown country, he changed his course, and went off to visit mr. jefferson at his estate of poplar forest in virginia, upon which the natural bridge is situated. passing through nashville on his way, he saw general andrew jackson at a horse race. he describes the hero of new orleans as an elderly man, "lean and lank, bronzed in complexion, deep marked countenance, grisly-gray hair, and a restless, fiery eye." he adds:-- "jackson had a horse on the course which was beaten that day. the recklessness of his bets, his violent gesticulations and imprecations, outdid all competition. if i had been told that he was to be a future president of the united states, i should have thought it a very strange thing." there are still a few old men, i believe, at nashville who remember general jackson's demeanor on the race ground, and they confirm the record of mr. flower. after a ride of a thousand miles or so, he presented his letter of introduction to mr. jefferson at poplar forest, and had a cordial reception. the traveler describes the house as resembling a french château, with octagon rooms, doors of polished oak, lofty ceilings, and large mirrors. the ex-president's form, he says, was of somewhat majestic proportions, more than six feet in height; his manners simple, kind, and polite; his dress a dark pepper-and-salt coat, cut in the old quaker fashion, with one row of large metal buttons, knee-breeches, gray worsted stockings, and shoes fastened by large metal buckles, all quite in the old style. his two grand-daughters, misses randolph, were living with him then. mr. jefferson soon after returned to his usual abode, monticello, and there mr. flower spent the greater part of the winter, enjoying most keenly the evening conversations of the ex-president, who delighted to talk of the historic scenes in which he was for fifty years a conspicuous actor. george flower and his party would have settled near monticello, perhaps, but for the system of slavery, which perpetuated a wasteful mode of farming, and disfigured the beautiful land with dilapidation. he had, meanwhile, sent home word that prairies existed in america, and in the spring of his partner in the enterprise, morris birkbeck, and his family of nine, came out from england, and they all started westward in search of the prairies. they went by stage to pittsburg, where they bought horses, mounted them and continued their journey, men, ladies, and boys, a dozen people in all. the journey was not unpleasant, most of them being persons of education and refinement, with three agreeable young ladies among them, two of them being daughters of mr. birkbeck, and miss andrews, their friend and companion. all went well and happily during the journey until mr. birkbeck, a widower of fifty-four with grown daughters, made an offer of marriage to miss andrews, aged twenty-five. it was an embarrassing situation. she was constrained to decline the offer, and as they were traveling in such close relations, the freedom and enjoyment of the journey were seriously impaired. then mr. flower, who was a widower also, but in the prime of life, proposed to the young lady. she accepted him, and they were soon after married at vincennes, the rejected birkbeck officiating as father of the bride. but this was not finding the prairies. at length, toward the close of the second summer, they began to meet with people who had seen prairies, and finally their own eyes were greeted with the sight. one day, after a ride of seven hours in extreme heat, bruised and torn by the brushwood, exhausted and almost in despair, suddenly a beautiful prairie was disclosed to their view. it was an immense expanse stretching away in profound repose beneath the light of an afternoon summer sun, surrounded by forest and adorned with clumps of mighty oaks, "the whole presenting a magnificence of park scenery complete from the hand of nature." the writer adds: "for once, the reality came up to the picture of the imagination." if the reader supposes that their task was now substantially accomplished, he is very much mistaken. after a good deal of laborious search, they chose a site for their settlement in edwards county, illinois, and bought a considerable tract; after which mr. flower went to england to close up the affairs of the two families, and raise the money to pay for their land and build their houses. they named their town albion. it has enjoyed a safe and steady prosperity ever since, and has been in some respects a model town to that part of illinois. the art of founding a town must of course soon cease to be practiced. it is curious to note how all the institutions of civilized life were established in their order. first was built a large log-cabin that would answer as a tavern and blacksmith's shop, the first requisites being to get the horses shod, and the riders supplied with whiskey. then came other log-cabins, as they were needed, which pioneers would undertake to build for arriving emigrants for twenty-five dollars apiece. very soon one of the people would try, for the first time in his life, to preach a sermon on sundays, and as soon as there were children enough in the neighborhood, one of the settlers, unable to cope with the labors of agriculture, would undertake to teach them, and a log-cabin would be built or appropriated for the purpose. mr. flower reports that, as soon as the school was established, civilization was safe. some boys and some parents would hold out against it for a while, but all of them at last either join the movement or remove further into the wilderness. "occasionally," he says, "will be seen a boy, ten or twelve years old, leaning against a door-post intently gazing in upon the scholars at their lessons; after a time he slowly and moodily goes away. he feels his exclusion. he can no longer say: 'i am as good as you.' he must go to school or dive deeper into the forest." all this is passing. already it begins to read like ancient history. george flower survived until march, , when he died at a good old age. certainly the historical society of chicago has done well to publish the record he left behind him. edward coles, noblest of the pioneers, and his great speech. when james madison came to the presidency in , he followed the example of his predecessor, mr. jefferson, in the selection of his private secretary. mr. jefferson chose captain meriwether lewis, the son of one of his virginia neighbors, whom he had known from his childhood. mr. madison gave the appointment to edward coles, the son of a family friend of albermarle county, va., who had recently died, leaving a large estate in land and slaves to his children. edward coles, a graduate of william and mary college, was twenty-three years of age when he entered the white house as a member of the president's family. he was a young man after james madison's own heart, of gentle manners, handsome person, and singular firmness of character. in the correspondence both of jefferson and madison several letters can be found addressed to him which show the very high estimation in which he was held by those eminent men. among the many young men who have held the place of private secretary in the presidential mansion, edward coles was one of the most interesting. i know not which ought to rank highest in our esteem, the wise and gallant lewis, who explored for us the western wilderness, or edward coles, one of the rare men who know how to surrender, for conscience' sake, home, fortune, ease, and good repute. while he was still in college he became deeply interested in the question, whether men could rightfully hold property in men. at that time the best of the educated class at the south were still abolitionists in a romantic or sentimental sense, just as queen marie antoinette was a republican during the american revolution. here and there a young man like george wythe had set free his slaves and gone into the profession of the law. with the great majority, however, their disapproval of slavery was only an affair of the intellect, which led to no practical results. it was not such with edward coles. the moment you look at the portrait given in the recent sketch of his life by mr. e. b. washburne, you perceive that he was a person who might be slow to make up his mind, but who, when he had once discovered the right course, could never again be at peace with himself until he had followed it. while at college he read everything on the subject of slavery that fell in his way, and he studied it in the light of the declaration of independence, which assured him that men are born free and equal and endowed with certain natural rights which are inalienable. he made up his mind, while he was still a student, that it was wrong to hold slaves, and he resolved that he would neither hold them nor live in a state which permitted slaves to be held. he was determined, however, to do nothing rashly. one reason which induced him to accept the place offered him by mr. madison was his desire of getting a knowledge of the remoter parts of the union, in order to choose the place where he could settle his slaves most advantageously. while he was yet a member of the presidential household, he held that celebrated correspondence with mr. jefferson, in which he urged the ex-president to devote the rest of his life to promoting the abolition of slavery. mr. jefferson replied that the task was too arduous for a man who had passed his seventieth year. it was like bidding old priam buckle on the armor of hector. "this enterprise," he added, "is for the young, for those who can follow it up and bear it through to its consummation. it shall have all my prayers and these are the only weapons of an old man. but, in the mean time, are you right in abandoning this property, and your country with it? i think not." mr. jefferson endeavored to dissuade the young man from his project of removal. mr. coles, however, was not to be convinced. after serving for six years as private secretary, and fulfilling a special diplomatic mission to russia, he withdrew to his ancestral home in virginia, and prepared to lead forth his slaves to the state of illinois, then recently admitted into the union, but still a scarcely broken expanse of virgin prairie. he could not lawfully emancipate his slaves in virginia, and it was far from his purpose to turn them loose in the wilderness. he was going with them, and to stay with them until they were well rooted in the new soil. all his friends and relations opposed his scheme; nor had he even the approval of the slaves themselves, for they knew nothing whatever of his intention. he had been a good master, and they followed him with blind faith, supposing that he was merely going to remove, as they had seen other planters remove, from an exhausted soil to virgin lands. placing his slaves in the charge of one of their number, a mulatto man who had already made the journey to illinois with his master, he started them in wagons on their long journey in april, , over the alleghany mountains to a point on the monongahela river. there he bought two large flat-bottomed boats, upon which he embarked his whole company, with their horses, wagons, baggage, and implements. his pilot proving a drunkard, he was obliged to take the command himself, upon reaching pittsburg. the morning after he left pittsburg, a lovely april day, he called all the negroes together on the deck of the boats, which were lashed together, and explained what he was going to do with them. he told them they were no longer slaves, but free people, free as he was, free to go on down the river with him, and free to go ashore, just as they pleased. he afterwards described the scene. "the effect on them," he wrote, "was electrical. they stared at me and at each other, as if doubting the accuracy or reality of what they heard. in breathless silence they stood before me, unable to utter a word, but with countenances beaming with expression which no words could convey, and which no language can now describe. as they began to see the truth of what they had heard, and to realize their situation, there came on a kind of hysterical, giggling laugh. after a pause of intense and unutterable emotion, bathed in tears, and with tremulous voices, they gave vent to their gratitude, and implored the blessings of god on me. when they had in some degree recovered the command of themselves, ralph said he had long known i was opposed to holding black people as slaves, and thought it probable i would some time or other give my people their freedom, but that he did not expect me to do it so soon; and moreover, he thought i ought not to do it till they had repaid me the expense i had been at in removing them from virginia, and had improved my farm and 'gotten me well fixed in that new country.' to this all simultaneously expressed their concurrence, and their desire to remain with me, as my servants, until they had comfortably fixed me at my new home. "i told them, no. i had made up my mind to give to them immediate and unconditional freedom; that i had long been anxious to do it, but had been prevented by the delays, first in selling my property in virginia, and then in collecting the money, and by other circumstances. that in consideration of this delay, and as a reward for their past services, as well as a stimulant to their future exertions, and with a hope it would add to their self-esteem and their standing in the estimation of others, i should give to each head of a family a quarter section, containing one hundred and sixty acres of land. to this all objected, saying i had done enough for them in giving them their freedom; and insisted on my keeping the land to supply my own wants, and added, in the kindest manner, the expression of their solicitude that i would not have the means of doing so after i had freed them. i told them i had thought much of my duty and of their rights, and that it was due alike to both that i should do what i had said i should do; and accordingly, soon after reaching edwardsville, i executed and delivered to them deeds to the lands promised them. "i stated to them that the lands i intended to give them were unimproved lands, and as they would not have the means of making the necessary improvements, of stocking their farms, and procuring the materials for at once living on them, they would have to hire themselves out till they could acquire by their labor the necessary means to commence cultivating and residing on their own lands. that i was willing to hire and employ on my farm a certain number of them (designating the individuals); the others i advised to seek employment in st. louis, edwardsville, and other places, where smart, active young men and women could obtain much higher wages than they could on farms. at this some of them murmured, as it indicated a partiality, they said, on my part to those designated to live with me; and contended they should all be equally dear to me, and that i ought not to keep a part and turn the others out on the world, to be badly treated, etc. i reminded them of what they seemed to have lost sight of, that they were free; that no one had a right to beat or ill-use them; and if so treated they could at pleasure leave one place and seek a better; that labor was much in demand in that new country, and highly paid for; that there would be no difficulty in their obtaining good places, and being kindly treated; but if not, i should be at hand, and would see they were well treated, and have justice done them. "i availed myself of the deck scene to give the negroes some advice. i dwelt long and with much earnestness on their future conduct and success, and my great anxiety that they should behave themselves and do well, not only for their own sakes, but for the sake of the black race held in bondage; many of whom were thus held because their masters believed they were incompetent to take care of themselves and that liberty would be to them a curse rather than a blessing. my anxious wish was that they should so conduct themselves as to show by their example that the descendants of africa were competent to take care of and govern themselves, and enjoy all the blessings of liberty and all the other birthrights of man, and thus promote the universal emancipation of that unfortunate and outraged race of the human family."[ ] after floating six hundred miles down the ohio, they had another land journey into illinois, where the master performed his promises, and created a home for himself. a few years after, he was elected governor of the state. it was during his term of three years that a most determined effort was made to change the constitution of the state so as to legalize slavery in it. it was chiefly through the firmness and masterly management of governor coles that this attempt was frustrated. when his purpose in moving to illinois had been completely accomplished, he removed to philadelphia, where he lived to the age of eighty-two. though not again in public life, he was always a public-spirited citizen. he corresponded with the venerable madison to the close of that good man's life. mr. madison wrote two long letters to him on public topics in his eighty-fourth year. governor coles died at philadelphia in , having lived to see slavery abolished in every state of the union. i have been informed that few, if any, of his own slaves succeeded finally in farming prairie land, but that most of them gradually drifted to the towns, where they became waiters, barbers, porters, and domestic servants. my impression is that he over-estimated their capacity. but this does not diminish the moral sublimity of the experiment. [ ] sketch of edward coles. by e. b. washburne. chicago. . peter h. burnett. when an aged bank president, who began life as a waiter in a backwoods tavern, tells the story of his life, we all like to gather close about him and listen to his tale. peter h. burnett, the first governor of california, and now the president of the pacific bank in san francisco, has recently related his history, or the "recollections of an old pioneer;" and if i were asked by the "intelligent foreigner" we often read about to explain the united states of to-day, i would hand him that book, and say:-- "there! that is the stuff of which america is made." he was born at nashville, tennessee, in ; his father a carpenter and farmer, an honest, strong-minded man, who built some of the first log-houses and frame-houses of what was then the frontier village of nashville, now a beautiful and pleasant city. while he was still a child the family removed to missouri, then on the outer edge of civilization, and they spent the first winter in a hovel with a dirt floor, boarded up at the sides, and with a hole in the middle of the roof for the escape of the smoke. all the family lived together in the same room. in a year or two, of course, they had a better house, and a farm under some cultivation. those pioneer settlements were good schools for the development of the pioneer virtues, courage, fortitude, handiness, directness of speech and conduct. fancy a boy ten years old going on horseback to mill through the woods, and having to wait at the mill one or two days and nights for his turn, living chiefly on a little parched corn which he carried with him, and bringing back the flour all right. "it often happened," says governor burnett, "that both bag and boy tumbled off, and then there was trouble; not so much because the boy was a little hurt (for he would soon recover), but because it was difficult to get the bag on again." there was nothing for it but to wait until a man came along strong enough to shoulder three bushels of corn. missouri was then, as it now is, a land of plenty; for besides the produce of the farms, the country was full of game, and a good deal of money was gained by the traffic in skins, honey, and beeswax. the simplicity of dress was such that a merchant attending church one day dressed in a suit of broadcloth, the aged preacher alluded to his "fine apparel," and condemned it as being contrary to the spirit of the gospel. fighting with fists was one of the chief amusements. at a training, some young bully would mount a stump, and after imitating the napping and crowing of a cock, cry out:-- "i can whip any man in this crowd except my friends." the challenge being accepted, the two combatants would fight until one of them cried, enough; whereupon they would wash their faces and take a friendly drink. men would sometimes lose a part of an ear, the end of a nose, or the whole of an eye in these combats, for it was considered within the rules to bite and gouge. in this wild country peter burnett grew to manhood, attending school occasionally in summer, and getting a pretty good rudimentary education. coming of intelligent, honest, able ancestors, he used his opportunities well, and learned a great deal from books, but more from a close observation of the natural wonders by which he was surrounded. his acute and kindly remarks upon the wild animals and wild nature of this continent could be profitably studied by almost any naturalist. it is surprising that one who has almost all his life lived on the advanced wave of civilization in this country should have acquired, among his other possessions, an extensive knowledge of literature, as well as of life and nature. nor is his case by any means uncommon. when he was nineteen his father gave him a horse three years old, a saddle and bridle, a new camlet cloak, and twenty-six dollars, and his mother furnished him with a good suit of jeans. soon after, he mounted his young horse and rode back to his native state, and took charge of the tavern aforesaid in the town of bolivar, hardiman county, of which tavern he was waiter, clerk, and book-keeper. here he had a pretty hard time. being very young, gawky, and ill-dressed, he was subject to a good deal of jesting and ridicule. but he was fond of reading. finding, by chance, at the house of an uncle, pope's translation of the iliad, he was perfectly entranced with it. "had it been gold or precious stones," he tells us, "the pleasure would not have equaled that which i enjoyed." nevertheless, he fancied that his ignorance, his country dress and uncouth manners caused him to be slighted even by his own relations. "i was badly quizzed," he says, "and greatly mortified; but i worked on resolutely, said nothing, and was always at the post of duty." promotion is sure to come to a lad of that spirit, and accordingly we soon find him a clerk in a country store earning two hundred dollars a year and his board, besides being head over ears in love with a beautiful girl. at first he did not know that he was in love; but, one day, when he had been taking dinner with her family, and had talked with the young lady herself after dinner a good while, he came out of the house, and was amazed to discover that the sun was gone from the sky. "in a confused manner," he relates, "i inquired of her father what had become of the sun. he politely replied, 'it has gone down!' i knew then that i was in love. it was a plain case." in those good old times marriage did not present the difficulties which it now does. he was soon married, obtained more lucrative employment, got into business for himself, failed, studied law, and found himself, at the age of thirty-six, the father of a family of six children, twenty-eight thousand dollars in debt, and, though in good practice at the bar, not able to reduce his indebtedness more than a thousand dollars a year. so he set his face toward oregon, then containing only three or four hundred settlers. he mounted the stump and organized a wagon-train, the roll of which at the rendezvous contained two hundred and ninety-three names. with this party, whose effects were drawn by oxen and mules, he started in may, , for a journey of seventeen hundred miles across a wilderness most of which had never been trodden by civilized men. for six months they pursued their course westward. six persons died on the way, five turned back, fifteen went to california, and those who held their course towards oregon endured hardships and privations which tasked their fortitude to the uttermost. mr. burnett surveyed the scenes of the wilderness with the eye of an intelligent and sympathetic observer. many of his remarks upon the phenomena of those untrodden plains are of unusual interest, whether he is discoursing upon animate or inanimate nature. arrived in oregon, an eight months' journey from washington, the settlers were obliged to make a provisional government for themselves, to which the tennessee lawyer lent an able hand. he relates an incident of the first collision between law and license. they selected for sheriff the famous joseph l. meek, a man of the best possible temper, but as brave as a lion. the first man who defied the new laws was one dawson, a carpenter, scarcely less courageous than meek himself. dawson, who had been in a fight, disputed the right of the sheriff to arrest him. the sheriff simply replied:-- "dawson, i came for you." the carpenter raised his plane to defend himself. meek wrested it from him. dawson picked up his broad axe, but on rising found himself within a few inches of meek's cocked revolver. "dawson," said the sheriff, laughing, "i came for you. surrender or die." dawson surrendered, and from that hour to the present, oregon has been ruled by law. in the course of five years the pioneer had brought under cultivation a good farm in oregon, which supported his family in great abundance, but did not contribute much to the reduction of those tennessee debts, which he was determined to pay if it took him all his life to do it. the news of the gold discovery in california reached oregon. he organized another wagon-train, and in a few months he and another lawyer were in the mining country, drawing deeds for town lots, from sunrise to sunset, at ten dollars a deed. they did their "level best," he says, and each made a hundred dollars a day at the business. again he assisted in the formation of a government, and he was afterwards elected the first governor of the state of california. at present, at the age of seventy-five, his debts long ago paid, a good estate acquired, and his children all well settled in life, he amuses himself with discounting notes in the pacific bank of san francisco. every person concerned in the management of a bank would do well to consider his wise remarks on the business of banking. when a man brings him a note for discount, he says, he asks five questions:-- . is the supposed borrower an honest man? . has he capital enough for his business? . is his business reasonably safe? . does he manage it well? . does he live economically? the first and last of these questions are the vital ones, he thinks, though the others are not to be slighted. [illustration: gerrit smith] gerrit smith. for many years we were in the habit of hearing, now and then, of a certain gerrit smith, a strange gentleman who lived near lake ontario, where he possessed whole townships of land, gave away vast quantities of money, and was pretty sure to be found on the unpopular side of all questions, beloved alike by those who agreed with him and those who differed from him. every one that knew him spoke of the majestic beauty of his form and face, of his joyous demeanor, of the profuse hospitality of his village abode, where he lived like a jovial old german baron, but without a baron's battle-axe and hunting spear. he was indeed an interesting character. without his enormous wealth he would have been, perhaps, a benevolent, enterprising farmer, who would have lived beloved and died lamented by all who knew him. but his wealth made him remarkable; for the possession of wealth usually renders a man steady-going and conservative. it is like ballast to a ship. the slow and difficult process by which honest wealth is usually acquired is pretty sure to "take the nonsense out of a man," and give to all his enterprises a practicable character. but here was a man whose wealth was more like the gas to a balloon than ballast to a ship; and he flung it around with an ignorance of human nature most astonishing in a person so able and intelligent. there was room in the world for one gerrit smith, but not for two. if we had many such, benevolence itself would be brought into odium, and we should reserve all our admiration for the close-fisted. his ancestors were dutchmen, long settled in rockland county, new york. gerrit's father owned the farm upon which major andré was executed, and might even have witnessed the tragedy, since he was twelve years old at the time. peter smith was his name, and he had a touch of genius in his composition, just enough to disturb and injure his life. at sixteen this peter smith was a merchant's clerk in new york, with such a love of the stage that he performed minor parts at the old park theatre, and it is said could have made a good actor. he was a sensitive youth, easily moved to tears, and exceedingly susceptible to religious impressions. while he was still a young man he went into the fur business with john jacob astor, and tramped all over western and northern new york, buying furs from the indians, and becoming intimately acquainted with that magnificent domain. the country bordering upon lake ontario abounded in fur-bearing animals at that period, and both the partners foretold rochester, oswego, and the other lake ports, before any white man had built a log hut on their site. astor invested his profits in city lots, but peter smith bought great tracts of land in northern and western new york. he sometimes bought townships at a single purchase, and when he died he owned in the state not far from a million acres. his prosperity, however, was of little advantage to him, for as he advanced in life a kind of religious gloom gained possession of him. he went about distributing tracts, and became at length so much impaired in his disposition that his wife could not live with him; finally, he withdrew from business and active life, made over the bulk of his property to his son, gerrit, and, settling in schenectady, passed a lonely and melancholy old age. gerrit smith, the son of this strong and perturbed spirit, was educated at hamilton college, near utica, where he figured in the character, very uncommon at colleges in those days, of rich man's son; a strikingly handsome, winning youth, with flowing hair and broad byron collar, fond of all innocent pleasures, member of a card club, and by no means inattentive to his dress. it seems, too, that at college he was an enthusiastic reader of passing literature, although in after days he scarcely shared in the intellectual life of his time. at the age of twenty-two he was a married man. he fell in love at college with the president's daughter, who died after a married life of only seven months. married happily a second time a year or two after, he settled at his well-known house in peterboro, a village near oswego, where he lived ever after. the profession of the law, for which he had prepared himself, he never practiced, since the care of his immense estate absorbed his time and ability; as much so as the most exacting profession. in all those operations which led to the development of oswego from an outlying military post into a large and thriving city, gerrit smith was of necessity a leader or participant,--for the best of his property lay in that region. and here was his first misfortune. rich as he was, his estate was all undeveloped, and nothing but the personal labor of the owner could make it of value. for twenty years or more he was the slave of his estate. he could not travel abroad; he could not recreate his mind by pleasure. albany, the nearest large town, was more than a hundred miles distant, a troublesome journey then; and consequently he had few opportunities of mingling with men of the world. he was a man of the frontier, an admirable leader of men engaged in the mighty work of subduing the wilderness and laying the foundations of empires. he, too, bought land, like his father before him, although his main interest lay in improving his estate and making it accessible. in the midst of his business life, when he was carrying a vast spread of sail (making canals, laying out towns, deep in all sorts of enterprises), the panic of struck him, laid him on his beam ends, and almost put him under water. he owed an immense sum of money--small, indeed, compared with his estate, but crushing at a time when no money could be raised upon the security of land. when he owned a million acres, as well as a great quantity of canal stock, plank-road stock, and wharf stock, and when fifteen hundred men owed him money, some in large amounts, he found it difficult to raise money enough to go to philadelphia. in this extremity he had recourse to his father's friend and partner, john jacob astor, then the richest man in north america. gerrit smith described his situation in a letter, and asked for a large loan on land security. mr. astor replied by inviting him to dinner. during the repast the old man was full of anecdote and reminiscence of the years when himself and peter smith camped out on the oswego river, and went about with packs on their backs buying furs. when the cloth was removed the terrible topic was introduced, and the guest explained his situation once more. "how much do you need?" inquired astor. "in all, i must have two hundred and fifty thousand dollars." "do you want the whole of it at once?" asked the millionaire. "i do," was the reply. astor looked serious for a moment, and then said:-- "you shall have it." the guest engaged to forward a mortgage on some lands along the oswego river, and a few days after, before the mortgage was ready, the old man sent his check for the two hundred and fifty thousand dollars. through the neglect of a clerk the mortgage papers were not sent for some weeks after, so that mr. astor had parted with this great sum upon no other security than a young man's word. but john jacob astor was a good judge of men, as well as of land. thus relieved, gerrit smith pursued his career without embarrassment, and in about twenty years paid off all his debts, and had then a revenue ranging from fifty to a hundred thousand dollars a year. he gave away money continuously, from thirty thousand to a hundred thousand dollars a year, in large sums and in small sums, to the deserving and the undeserving. of course, he was inundated with begging letters. every mail brought requests for help to redeem farms, to send children to school, to buy a piano, to buy an alpaca dress with the trimmings, to relieve sufferers by fire, and to pay election expenses. "the small checks," mr. frothingham tells us, "flew about in all directions, carrying, in the aggregate, thousands of dollars, hundreds of which fell on sandy or gravelly soil, and produced nothing." he gave, in fact, to every project which promised to relieve human distress, or promote human happiness. he used to have checks ready drawn to various amounts, only requiring to be signed and supplied with the name of the applicant. on one occasion he gave fifty dollars each to all the old maids and widows he could get knowledge of in the state of new york--six hundred of them in all. he gave away nearly three thousand small farms, from fifteen to seventy-five acres each, most of them to landless colored men. "for years," said he, "i have indulged the thought that when i had sold enough land to pay my debts, i would give away the remainder to the poor. i am an agrarian. i would that every man who desires a farm might have one, and no man covet the possession of more farms than one." i need not say that these farms were of little benefit to those who received them, for our colored friends are by no means the men to go upon a patch of northern soil and wring an independent livelihood out of it. gerrit smith was a sort of blind, benevolent samson, amazingly ignorant of human nature, of human life, and of the conditions upon which alone the welfare of our race is promoted. he died in , aged seventy-seven, having lived one of the strangest lives ever recorded, and having exhibited a cast of character which excites equal admiration and regret. peter force. one of the interesting sights of the city of washington used to be the library of "old peter force," as he was familiarly called,--colonel peter force, as he was more properly styled. he was one of the few colonels of that day who had actually held a colonel's command, having been regularly commissioned by the president of the united states as a colonel of artillery in the district of columbia. he might, indeed, have been called major-general, for in his old age he held that rank in the militia of the district. and a very fine-looking soldier he must have been in his prime, judging from the portrait which used to hang in the library, representing a full-formed man, tall and erect, his handsome and benevolent countenance set off by an abundance of curly hair. his library had about the roughest furniture ever seen in an apartment containing so much that was valuable. as i remember it, it was a long, low room, with streets and cross-streets of pine book-shelves, unpainted, all filled with books to their utmost capacity--a wilderness of books, in print and in manuscript, mostly old and dingy, and almost all of them relating in some way to american history. the place had a very musty smell; and as most of its treasures were in the original bindings, or without bindings, few persons would have suspected the priceless value of the collection. i am acquainted with a certain library in new york of several thousand volumes, most of which are bound resplendently in calf and gold, and the room in which they are kept is "as splendid as a steamboat," but old peter force could show you single alcoves of his library which, at a fair valuation, would buy out all that mass of sumptuosity. it was not always easy to find the old gentleman in his dusty, dingy wilderness; but when you had discovered him in some remote recess he would take pleasure in exhibiting his treasures. he would take down his excellent copy of eliot's indian bible, a book so faithfully made in every respect that i question if, as a mere piece of book-making, it could now be matched in the united states. he lived to see this rarity command in new york the price of fourteen hundred and fifty dollars. he would show you forty-one works, in the original editions, of increase and cotton mather, the most recent of which was published in . he possessed a large number of books printed and bound by benjamin franklin. he had two hundred volumes of the records of colonial legislatures. he could show you a newspaper of almost every month--nay, almost every week, since newspapers were first published in america. he had in all nine hundred and fifty bound volumes of newspapers, of which two hundred and forty-five volumes were published before the year . he would show you a collection of more than thirty-nine thousand pamphlets, of which eight thousand were printed before the year . his collection of maps relating to america was truly wonderful. besides all the early atlases of any note, he had over a thousand detached maps illustrative both of the geography and history of america; for many of them were maps and plans drawn for military purposes. he would show you, perhaps, a pen-drawing of date , by a british officer, upon which was written: "plan of the rebel works at west point." he had also several plans by british officers of "the rebel works" around boston during the revolution. besides such things (and he had over three hundred plans and maps of which there was no other copy in existence), he possessed a surprising number of books printed in the infancy of the printer's art; among them specimens representing every year from onward. he had more than two hundred and fifty books printed before the year , so arranged that a student could trace the progress of the art of printing from the days of caxton. he had also a vast collection of manuscripts, numbering four hundred and twenty-nine volumes, many of which were of particular interest. the whole number of volumes in the library was , , and the number of pamphlets nearly , . the reader, perhaps, imagines that the collector of such a library must have been a very rich man, and that he traveled far and wide in search of these precious objects. not at all. he never was a rich man, and i believe he rarely traveled beyond the sight of the dome of the capitol. indeed, the most wonderful thing about his collection was that he, who began life a journeyman printer, and was never in the receipt of a large income, should have been able to get together so vast an amount of valuable material. part of the secret was that when he began to make his collection these things were not valued, and he obtained many of his most precious relics by merely taking the trouble to carry them away from the garrets in which they were mouldering into dust, unprized and unknown. a wise old new york merchant, long ago himself mouldered into dust, used to say:-- "men generally get in this world exactly what they _want_." "how can that be?" asked a youngster one day. "almost everybody in new york wants to be rich, but very few of them ever will be. i _want_ a million or so myself." "ah, boy," the old man replied, "you want a million; but you don't want it enough. what you _want_ at present is pleasure, and you want it so much that you are willing to spend all your surplus force, time, and revenue to get it. if you wanted your million as much as you _want pleasure_, by and by, when you have a bald head like mine, you would have your million." peter force was a very good illustration of the old merchant's doctrine. he got all these precious things because he wanted them with a sustained passion of desire for half a century. there never was a time when he would not have gladly got up in the middle of the night and walked ten miles, in the face of a northeasterly storm, to get a rare pamphlet of four pages. he was a miser of such things. but, no; that word does not describe him; for one of the greatest pleasures of his life was to communicate his treasures to others; and he communicated to the whole american people the best of his collections in massive volumes of american archives. he was a miser only in the strength of his desire. "more than once," he said to mr. george w. greene, "did i hesitate between a barrel of flour and a rare book; but the book always got the upper hand." to the same friend he made a remark which shows that his desire to communicate was quite as strong as his desire to obtain. "whenever," said he, "i found a little more money in my purse than i absolutely needed, i published a volume of historical tracts." it was interesting to hear the old man relate how this taste for the treasures of history was formed in his mind. his father, who served, during the revolution, in a new jersey regiment, retired after the war to the city of new york, and at his house the jersey veterans liked to meet and talk over the incidents of the campaigns they had made together. peter, as a boy, loved to hear them tell their stories, and, as he listened, the thought occurred to him one evening, why should all this be forgotten? boy as he was, he began to write them down, under the title of "the unwritten history of the war in new jersey." he made considerable progress in it, but unfortunately the manuscript was lost. the taste then formed grew with his growth and strengthened with his strength. at ten he left school forever, and went into a printing office, which has proved an excellent school to more than one valuable american mind. he became an accomplished printer, and at twenty-two was elected president of the new york typographical society, an organization which still exists. then the war of began. like his father before him, he served in the army, first as private, then as sergeant, then as sergeant-major, then as ensign, finally as lieutenant. the war ended. he went to washington as foreman of a printing office, and at washington, as printer, editor, publisher and collector, he lived the rest of his long and honorable life; never rich, as i have before remarked, though never without a share of reasonable prosperity. the most important work of his life was the publication of the american archives, in which he was aided by congress; he furnishing the documents and the labor, and congress paying the cost of publication. through the nine volumes of this work a great number of the most curious and interesting records and memorials of american history are not only preserved, but made accessible to all students who can get near a library. he had all the state-houses of the country ransacked for documents, and a room was assigned him in the department of state in which his clerks could conveniently copy them. all went well with the work until william marcy became secretary of state, whose duty it was to examine and approve each volume before it went to the printer. when peter force presented the manuscript of the tenth volume to secretary marcy he received a rebuff which threw a cloud over several years of his life. "i don't believe in your work, sir," said the secretary. "it is of no use to anybody. i never read a page of it, and never expect to." "but," said mr. force, "the work is published in virtue of a contract with the government. here is the manuscript of the tenth volume. if there is anything there which you think ought not to be there, have the goodness to point it out to me." "you may leave the papers, sir," said the secretary. he left the papers; but neither marcy nor his successors ever found time to examine that tenth volume, though on the first day of every official year the compiler called their attention to it. for seven years he was a suitor on behalf of his beloved tenth volume, and then the war occurred and all such matters were necessarily put aside. he was now seventy-one years of age, and his great desire was to dispose of his library in such a way that its treasures would not be scattered abroad, and perhaps lost forever to the country. at length, congress having sanctioned the enlargement of their own library, their librarian, mr. spofford, induced them to purchase the whole mass, just as it stood, for one hundred thousand dollars, and the collection now forms part of the congressional library. colonel force lived to the year , when he died at washington, universally beloved and lamented, in the seventy-eighth year of his age, enjoying almost to the last two of the things he loved best--his books and his flowers. john bromfield, merchant. john bromfield's monument is more lasting than brass. it was he who left to the city of newburyport, in massachusetts, ten thousand dollars for planting and preserving trees in the streets, and keeping the sidewalks in order. the income of this bequest would not go far in any other sort of monument, but it has embowered his native city in beautiful trees. every spring other trees are planted, and, as long as that bequest is faithfully administered, he cannot be forgotten. nothing brings a larger or surer return than money judiciously spent in making towns and cities pleasant. it not only yields a great revenue of pleasure and satisfaction to the inhabitants; it not only benefits every individual of them every hour, but it invites residents from abroad; it is a standing invitation to persons of taste and good sense. the wisest thing the city of new york ever did, next to the introduction of the croton water, was the creation of the central park; the one feature which redeems the city from the disgrace of its dirty streets and its agonizing tenement region. this john bromfield, merchant, was just such a thoughtful and benevolent man as we should naturally expect to find him from his bequest. he belonged to a class of merchants which is rapidly becoming extinct. the cable telegraph and the steam freight ship are superseding the merchants of moderate capital, and are concentrating the great business of interchanging commodities in the hands of a few houses who reckon their capital by millions. born at newburyport, in , he was brought up by excellent parents near boston, who practiced the old-fashioned system of making him hardy and self-helpful. his mother used to say that when he was old enough to wear leather shoes she bored holes in the soles in order to accustom him to wet feet, so that he might be made less liable to catch cold from that cause. this appears to have been a custom of that generation, for it is recorded of the mother of josiah quincy that she would never let him take off his wet shoes, regarding it as an effeminate practice. on approaching the time of entering college his father met with misfortunes and could not bear the expense. two aunts of his, who could well afford it, offered to pay his expenses in college. he firmly declined the offer. the foundation of his character and career was a love of independence. he asked to be apprenticed, as the custom then was, to a mercantile house, and remained in it as long as it held together. after its failure he tried for months to obtain a clerkship, but, not succeeding, he arranged with a carpenter to learn his trade. just before putting on the carpenter's apron an opening occurred in his own business, and he became a merchant. about the year he went out to china as supercargo, and continued to visit that part of the world in similar capacities for many years, occasionally making small ventures of his own, and slowly accumulating a little capital. he had a series of the most discouraging misfortunes. in the year he wrote to his sister from cadiz:-- "it is a melancholy truth that in the whole course of my life i never arrived at a good market." on that occasion everything promised well. he had a ship full of valuable goods, and the market to which he was carrying them was in an excellent condition for his purpose, but within twenty-four hours of his port he was captured, and detained ten weeks a prisoner. after the peace of , merchants could send their ships across the ocean without fear of their being taken by english or french cruisers. from that time he had better luck, and gradually gained a moderate fortune, upon which he retired. he never kept a store, or had any sort of warehouse, but made his fortune by sending or taking merchandise from a port which had too much of it to one that was in want of it. on one of his winter passages to europe he found the sailors suffering extremely from handling frozen ropes, as they were not provided with mittens. being a yankee, and having been brought up to _do_ things as well as read about them, he took one of his thick overcoats and made with his own hands a pair of mittens for every sailor. on another occasion, in the ship atahualpa, in , bound to china, the vessel was attacked off macao by pirates, in twenty-two junks, some of them being twice the tonnage of the vessel. captain sturgis, who commanded the vessel, defended her with signal ability and courage, and kept the pirates off for forty minutes, until the vessel gained the protection of the fort. john bromfield, a passenger on board, took command of a gun, and seconded the endeavors of the captain with such coolness and promptitude as to contribute essentially to the protection of the vessel. in retirement he lived a quiet life in boston, unmarried, fond of books, and practicing unusual frugality for a person in liberal circumstances. he had a singular abhorrence of luxury, waste, and ostentation. he often said that the cause of more than half the bankruptcies was spending too much money. nothing could induce him to accept personal service. he was one of those men who wait upon themselves, light their own fire, reduce their wants to the necessaries of civilized life, and all with a view to a more perfect independence. he would take trouble to oblige others, but could not bear to put any one else to trouble. this love of independence was carried to excess by him, and was a cause of sorrow to his relations and friends. he was a man of maxims, and one of them was:-- "the good must merit god's peculiar care, and none but god can tell us who they are." another of his favorite couplets was pope's:-- "reason's whole pleasure, all the joys of sense, lie in three words: health, peace, and competence." he used to quote burns's stanza about the desirableness of wealth:-- "not to hide it in a hedge, nor for a train attendant; but for the glorious privilege of being independent." he was utterly opposed to the way in which business was then conducted--hazardous enterprises undertaken upon borrowed capital. the excessive credit formerly given was the frequent theme of his reprobation. how changed the country, even in the short space of sixty years! in he made a journey from boston to new orleans, and his letters show curious glimpses of life and travel as they then were. leaving boston at four o'clock on a friday morning, he reached new york at ten o'clock on saturday morning, and he speaks of this performance with astonishment. boston to new york in thirty hours! he was in new york november , , when the opening of the erie canal was celebrated. he did not care much for the procession. "there was, however," he adds, "an interesting exhibition of steamboats, probably greater than could be found at any other place in the world; say, _from twenty-five to thirty_, and most of them of a large class." he was in the valley of the ohio that year, and he spoke of it "as the land of cheapness:" flour, two dollars and a quarter a barrel; oats, twelve and a half cents a bushel; corn and rye, twenty cents; coal, three cents. he found all the region from louisville to louisiana "one vast wilderness," with scarcely any settlements, and now and then a log hut on the banks, occupied by the people who cut wood for the steamboats. on the prairies of missouri he rode miles and miles without seeing a house. indiana was an almost unbroken wilderness: corn ten cents a bushel, a wild turkey twelve and half cents, and other things in proportion. nevertheless, travelers at that day had some pleasures which could be advantageously compared with the ease and comfort of the pullman car. the alleghanies were then crossed by open wagons drawn by splendid pennsylvania horses, six in a team, gayly decorated with ribbons, bells, and trappings. he used to repeat, in a peculiarly buoyant and delightful manner, a popular song of the day, called "the wagoner," suggested by the apparently happy lot of the boys who rode and drove these horses. some readers may remember the old song, beginning:-- "i've often thought if i were asked whose lot i envied most, what one i thought most lightly tasked of man's unnumbered host, i'd say i'd be a mountain boy and drive a noble team--wo hoy! wo hoy! i'd cry, and lightly fly into my saddle seat; my rein i'd slack, my whip i'd crack-- what music is so sweet? six blacks i'd drive, of ample chest, all carrying high their head. all harnessed tight, and gaily dressed in winkers tipped with red. oh, yes! i'd be a mountain boy, and such a team i'd drive--wo hoy! wo hoy! i'd cry; the lint should fly. wo hoy! dobbin, ball. their feet should ring, and i would sing, i'd sing my fal-de-roll." we have almost forgotten that such a gay mode of crossing the alleghanies was ever practiced; and yet a person need not be very old to have enjoyed the experience. i myself, for example, can just remember riding from buffalo to new york by a line of stages that came round by the alleghany mountains, and crossed the state of new jersey, passing through morristown. we were just six days in performing the journey. this excellent man, after a tranquil and happy life, died in , aged seventy, and left considerable sums to benevolent societies. his estate proved to be of about two hundred thousand dollars value, which was then considered very large, and he bestowed something more than half of it upon institutions for mitigating human woe. ten thousand of it he gave for the promotion of pleasure, and the evidences of his forethought and benevolence are waving and rustling above my head as these lines are written. his memory is green in newburyport. all the birds and all the lovers, all who walk and all who ride, the gay equestrian and the dusty wayfarer, the old and the invalid who can only look out of the window, all owe his name a blessing. frederick tudor, ice exporter. edward everett used to relate a curious anecdote of the time when he was the american minister at london. he was introduced one day to an eastern prince, who greeted him with a degree of enthusiasm that was altogether unusual and unexpected. the prince launched into eulogium of the united states, and expressed a particular gratitude for the great benefit conferred upon the east indies by mr. everett's native massachusetts. the american minister, who was a good deal puzzled by this effusion, ventured at length to ask the prince what special benefit massachusetts had conferred upon the east indies, wondering whether it was the missionaries, or the common school system, or daniel webster's bunker hill oration. "i refer," said the prince, "to the great quantity of excellent ice which comes to us from boston." mr. everett bowed with his usual politeness, but was much amused at the excessive gratitude of the prince for the service named. the founder of this foreign ice business, which has now attained such large proportions, was a boston merchant named frederick tudor, son of that colonel william tudor who studied law under john adams, and who served his country on the staff of general washington, and afterwards became a judge. frederick tudor, who was born in , the year of the peace between england and the united states, entered early into business, being at twenty-two already owner of a vessel trading with the west indies. it was in that the idea of exporting ice first occurred to him--an idea which, as he was accustomed to relate in his old age, was received with derision by the whole town as a "mad project." he had made his calculations too carefully, however, to be disturbed by a little ridicule; and that same year he sent out his first cargo of a hundred and thirty tons, to the island of martinique. the result justified his confidence. the ice arrived in perfect condition, and he was encouraged to follow up his single cargo with many others larger and more profitable. during the war of business was somewhat interrupted by the english cruisers, which were ever on the alert for prizes in the west indian waters, but, after peace was declared, his trade increased rapidly. he supplied ice to charleston and new orleans also, those cities at first requiring but a ship-load each per annum, although the demand increased so rapidly that a few years later new orleans alone consumed thirty cargoes. almost from the first, mr. tudor had believed that ice could be transported as safely and profitably to calcutta as to havana; but he could not bring others to share this opinion--at least, not to the point of risking money upon it. it was not, therefore, until , twenty-nine years later than his martinique experiment, that he sent his first cargo of one hundred and eighty tons of ice to india. notwithstanding a waste of one third of the whole cargo during the voyage, he was able to sell this massachusetts ice at one half the price charged for the artificially frozen ice formerly used in calcutta by the few families who could afford such a luxury. the cold commodity which he provided met, therefore, with a warm welcome from the english inhabitants. they recognized the boon afforded them, and expressed their gratitude by raising a subscription and presenting to the enterprising yankee merchant a fire-proof building in which to store his ice. he met them in the same spirit of wise liberality, and sold the article at no more than a reasonable profit--about three cents a pound--which enabled the great body of english residents to use the ice habitually. mr. tudor used to boast that in jamaica he sold the best wenham ice at half the price which an inferior article brought in london; and even at calcutta he made ice cheaper than it was in london or paris. on the passage to the east indies, ice is four or five months at sea, traverses sixteen thousand miles of salt water, and crosses the equator twice; and on its arrival it is stored in massive double-walled houses, which are covered by four or five separate roofs. it has also to be unloaded in a temperature of ninety to one hundred degrees. notwithstanding all this, the inhabitants of the most distant tropical seaports are supplied with ice every day of the year at the moderate price mentioned above. it was frederick tudor also who originated and developed the best methods of cutting, packing, storing, and discharging ice, so as to reduce the waste to the minimum. i am assured by a gentleman engaged in the business that the blocks of ice now reach calcutta, after the long voyage from boston, with a waste scarcely noticeable. the vessels are loaded during the cold snaps of january, when water will freeze in the hold of a vessel, and when the entire ship is penetrated with the intensest cold. the glittering blocks of ice, two feet thick, at a temperature below zero, are brought in by railroad from the lakes, and are placed on board the ships with a rapidity which must be seen to be appreciated. the blocks are packed in sawdust, which is used very much as mortar is used in a stone wall. between the topmost layer of ice and the deck there is sometimes a layer of closely packed hay, and sometimes one of barrels of apples. it has occasionally happened that the profit upon the apples has paid the freight upon the ice, which usually amounts to about ten thousand dollars, or five dollars a ton. the arrival of an ice ship at calcutta is an exhilarating scene. clouds of dusky natives come on board to buy the apples, which are in great request, and bring from ten to thirty cents each, according to the supply. happy is the native who has capital enough to buy a whole barrel of the fruit. off he trudges with it on his back to the place of sale, or else puts it on a little cart and peddles the apples about the streets. in a day or two that portion of the cargo has disappeared, and then the ice is to be unloaded. it was long before a native could be induced to handle the crystal blocks. tradition reports that they ran away affrighted, thinking the ice was something bewitched and fraught with danger. but now they come on board in a long line, and each of them takes a huge block of ice upon his head and conveys it to the adjacent ice-house, moving with such rapidity that the blocks are exposed to the air only a few seconds. once deposited there, the waste almost ceases again, and the ice which cost in boston four dollars a ton is worth fifty dollars. when frederick tudor had been employed twenty-five years in this trade, finding it inconvenient to be separated from the great body of merchants, he embarked again in general mercantile business, by way of re-uniting himself to his former associates. the experiment resulted in ruinous losses. in less than three years he was a bankrupt, and owed his creditors two hundred and ten thousand dollars more than he could pay. the ice business being still profitable and growing, it was proposed to him that he should conduct it as the agent of his creditors, retaining a specified sum per annum for his personal expenses. to this he objected, and said to them:-- "allow me to proceed, and i will work for you better than i can under any restriction. give me the largest liberty, and i will pay the whole in time with interest." he was then fifty-two years of age, and he had undertaken to pay an indebtedness, the mere interest of which was about ten thousand dollars a year. by the time he had got fairly at work the treachery of an agent whom he had raised from poverty to wealth lost him his havana monopoly, his principal source of profit. then it became necessary to buy land bordering the lakes from which he gathered ice, and to erect in calcutta, new orleans, and elsewhere expensive and peculiarly constructed buildings for storage. occasionally, too, he experienced the losses and adverse incidents from which no business is exempt. nevertheless, in fourteen years from the date of his bankruptcy he had paid his debts, principal and interest, amounting to two hundred and eighty thousand dollars, besides having acquired a large quantity of real estate, some of which had increased in value tenfold. thus, while paying his debts, and in the very process of paying, and while thinking only of his creditors' interest, he had gained for himself a very large fortune. he continued an ice merchant for more than fifty years; or, as he said himself:-- "i began this trade in the youthful hopes attendant on the age of twenty-two. i have followed it until i have a head with scarcely a hair that is not white." it was this enterprising merchant who may be said to have created the beautiful seaside retreat near boston called nahant, where he invented many ingenious expedients for protecting trees and shrubs from the east winds which lacerate that rock-bound coast. his gardens and plantations in nahant were famous many years before his death. he died in , aged eighty-one, leaving to his children and to his native state a name which was honorable when he inherited it, and the lustre of which his life increased. [illustration: yours myron holley] myron holley, market-gardener. fifty years ago, this man used to sell vegetables and fruit from door to door in the streets of rochester, n. y. he had a small farm a few miles out of town, upon which he raised the produce which he thus disposed of. an anecdote is related of a fine lady who had recently come to rochester as the wife of one of its most distinguished clergymen. she ran up into her husband's study one morning, and said to him:-- "why, doctor, i've just seen the only gentleman i have yet met with in rochester, and he was at our basement door selling vegetables. how wonderful! who is it? who can it be?" "it must be myron holley," said her husband. another of his lady customers used to say that he sold early peas and potatoes in the morning with as much grace as he lectured before the lyceum in the evening. nor was it the ladies alone who admired him. the principal newspaper of the city, in recording his death in , spoke of him as "an eminent citizen, an accomplished scholar, and noble man, who carried with him to the grave the love of all who knew him." in reflecting upon the character of this truly remarkable person, i am reminded of a newfoundland dog that i once had the honor of knowing near the spot on the shore of lake ontario where myron holley hoed his cabbages and picked his strawberries. it was the largest and most beautiful dog i have ever seen, of a fine shade of yellow in color, and of proportions so extraordinary that few persons could pass him without stopping to admire. he had the strength and calm courage of a lion, with the playfulness of a kitten, and an intelligence that seemed sometimes quite human. one thing this dog lacked. he was so destitute of the evil spirit that he would not defend himself against the attacks of other dogs. he seemed to have forgotten how to bite. he has been known to let a smaller dog draw blood from him without making the least attempt to use his own teeth in retaliation. he appeared to have lost the instinct of self-assertion, and walked abroad protected solely, but sufficiently, by his vast size and imposing appearance. myron holley, i say, reminds me of this superb and noble creature. he was a man of the finest proportions both of body and of mind, beautiful in face, majestic in stature, fearless, gifted with various talents, an orator, a natural leader of men. with all this, he was destitute of the personal ambition which lifts the strong man into publicity, and gives him commonplace success. if he had been only half as good as he was, he might have been ten times as famous. he was born at salisbury, conn., in , the son of a farmer who had several sons that became notable men. the father, too, illustrated some of the best traits of human nature, being one of the men who make the strength of a country without asking much from the country in return. he used to say to his sons that the height of human felicity was "to be able to converse with the wise, to instruct the ignorant, to pity and despise the intriguing villain, and to assist the unfortunate." his son myron enjoyed this felicity all the days of his life. after graduating at williams, and studying law at new haven, he set his face toward western new york, then more remote from new england than oregon now is. he made an exquisite choice of a place of residence, the village of canandaigua, then only a hamlet of log huts along the border of one of the lakes for which that part of the state is famous. the first step taken by the young lawyer after his arrival fixed his destiny. he was assigned by the court to defend a man charged with murder--a capital chance for winning distinction in a frontier town. myron holley, however, instead of confining himself to his brief and his precedents, began by visiting the jail and interviewing the prisoner. he became satisfied of his guilt. the next morning he came into court, resigned the case, and never after made any attempt to practice his profession. he was, in fact, constitutionally disqualified for the practice of such a calling. having a little property, he bought out a bookseller of the village, laid out a garden, married, was soon elected county clerk, and spent the rest of his life in doing the kind of public service which yields the maximum of good to the country with the minimum of gain to the individual doing it. the war of filled all that region with distress and want. it was he who took the lead in organizing relief, and appealed to the city of new york for aid with great success. as soon as the war was over, the old scheme of connecting lake erie with the hudson by a canal was revived. it was an immense undertaking for that day, and a great majority of the prudent farmers of the state opposed the enterprise as something beyond their strength. it was myron holley who went to the legislature year after year, and argued it through. his winning demeanor, his persuasive eloquence, his intimate knowledge of the facts involved, his entire conviction of the wisdom of the scheme, his tact, good temper, and, above all, his untiring persistence, prevailed at length, and the canal was begun. he was appointed one of the commissioners to superintend the construction of the canal at a salary of twenty-five hundred dollars a year. the commissioners appointed him their treasurer, which threw upon him for eight years an inconceivable amount of labor, much of which had to be done in situations which were extremely unhealthy. at one time, in , he had a thousand laborers on his hands sick with malaria. he was a ministering angel to them, friend, physician, and sometimes nurse. he was obliged on several occasions to raise money for the state on his personal credit, and frequently he had to expend money in circumstances which made it impossible for him to secure the legal evidence of his having done so. in the work was done. a procession of boats floated from lake erie to new york harbor, where they were received by a vast fleet of steamboats and other vessels, all dressed with flags and crowded with people. in the midst of this triumph, myron holley, who had managed the expenditures with the most scrupulous economy, was unable to furnish the requisite vouchers for a small part of the money which had passed through his hands. he at once gave up his small estate, and appealed to the legislature for relief. he was completely vindicated; his estate was restored to him; but he received no compensation either for his services or his losses. he returned to his garden, however, a happy man, and during the greater part of the rest of his life he earned a modest subsistence by the beautiful industry which has since given celebrity and wealth to all that fertile region. he remained, however, to the end of his days, one of those brave and unselfish public servants who take the laboring oar in reforms which are very difficult or very odious. after the abduction of morgan, he devoted some years to anti-masonry, and he founded what was called the liberty party, which supported mr. birney, of kentucky, for the presidency. one of his fellow-workers, the hon. elizur wright, of boston, has recently published an interesting memoir of him, which reveals to us a cast of character beautiful and rare in men; a character in which the moral qualities ruled with an easy and absolute sway, and from which the baser traits appeared to be eliminated. he was like that great, splendid, yellow king of dogs which escaped perfection by not having just a spice of evil in his composition. let me add, however, that he was as far as possible from being a "spoony." mr. wright says:-- "he had the strength of a giant, and did not abstain from using it in a combative sense on a fit occasion. when his eldest daughter was living in a house not far from his own, with her first child in her arms, he became aware that she was in danger from a stout, unprincipled tramp who had called on her as a beggar and found her alone. hastening to the house, without saying a word he grasped the fellow around body and both arms, and carried him, bellowing for mercy, through the yard and into the middle of the street, where he set him down. greatly relieved, the miserable wretch ran as if he had escaped from a lion." mr. wright adds another trait: "once in lyons (n. y.) when there was great excitement about the 'sin of dancing,' the ministers all preaching and praying against it, myron holley quietly said: 'it is as natural for young people to like to dance as for the apple trees to blossom in the spring.'" the founders of lowell. we do not often hear of strikes at lowell. some men tell us it is because there are not as many foreigners there as at certain manufacturing centres where strikes are frequent. this cannot be the explanation; for out of a population of seventy-one thousand, there are more than twenty thousand foreign-born inhabitants of lowell, of whom more than ten thousand are natives of ireland. to answer the question correctly, we must perhaps go back to the founding of the town in , when there were not more than a dozen houses on the site. at that time the great water-power of the merrimac river was scarcely used, and there was not one cotton manufactory upon its banks. at an earlier day this river and its tributaries swarmed with beaver and other fur-yielding creatures, which furnished a considerable part of the first capital of the pilgrim fathers. the indians trapped the beaver, and carried the skins to plymouth and boston; and this is perhaps the reason why the merrimac and most of its branches retain their indian names merrimac itself is an indian word meaning sturgeon, and of its ten tributaries all but two appear to have indian names: contoocook, soucook, suncook, piscatagoug, souhegan, nashua, concord, spiggot, shawshine, and powow. besides these there are the two rivers which unite to form it, the names of which are still more peculiar: pemigewasset and winnepiseogee. the most remarkable thing with regard to these names is, that the people who live near see nothing remarkable in them, and pronounce them as naturally as new yorkers do bronx and croton. it is difficult for us to imagine a lover singing, or saying, "meet me by the pemigewasset, love," or asking her to take a row with him on the lovely winnepiseogee. but lovers do such things up there; and beautiful rivers they are, flowing between mountains, and breaking occasionally into falls and rapids. the merrimac, also, loses its serenity every few miles, and changes from a tranquil river into a--water-power. in november, , a light snow already covering the ground, six strangers stood on the banks of the merrimac upon the site of the present city of lowell. a canal had been dug around the falls for purposes of navigation, and these gentlemen were there with a view to the purchase of the dam and canal, and erecting upon the site a cotton mill. their names were patrick t. jackson, kirk boott, warren dutton, paul moody, john w. boott, and nathan appleton; all men of capital or skill, and since well known as the founders of a great national industry. they walked about the country, observed the capabilities of the river, and made up their minds that that was the place for their new enterprise. "some of us," said one of the projectors, "may live to see this place contain twenty thousand inhabitants." the enterprise was soon begun. in the town was incorporated and named. it is always difficult to name a new place or a new baby. mr. nathan appleton met one of the other proprietors, who told him that the legislature was ready to incorporate the town, and it only remained for them to fill the blank left in the act for the name. "the question," said he, "is narrowed down to two, lowell or derby." "then," said mr. appleton, "lowell, by all means." it was so named from mr. francis c. lowell, who originated the idea. he had visited england and scotland in , and while there had observed and studied the manufacture of cotton fabrics, which in a few years had come to be one of the most important industries of the british empire. the war of intervened; but before the return of peace mr. lowell took measures for starting the business in new england. a company was formed with a capital of four hundred thousand dollars, and mr. lowell himself undertook the construction of the power loom, which was still guarded in europe as a precious secret. after having obtained all possible information about it, he shut himself up in a boston store with a man to turn his crank, and experimented for months till he had conquered the difficulties. in the fall of the machine was ready for inspection. "i well recollect," says mr. appleton, "the state of admiration and satisfaction with which we sat by the hour watching the beautiful movement of this new and wonderful machine, destined as it evidently was to change the character of all textile industry." in a few months the first manufactory was established in waltham, with the most wonderful success. henry clay visited it, and gave a glowing account of it in one of his speeches, using its success as an argument against free trade. it is difficult to see what protection the new manufacture required. the company sold its cotton cloth at thirty cents a yard, and they afterwards found that they could sell it without loss at less than seven cents. the success of the waltham establishment led to the founding of lowell, lawrence, nashua, and manchester. there are now at lowell eighty mills and factories, in which are employed sixteen thousand men and women, who produce more than three million yards of fabric every week. the city has a solid inviting appearance, and there are in the outskirts many beautiful and commanding sites for residences, which are occupied by men of wealth. but now as to the question above proposed. why are the operatives at lowell less discontented than elsewhere? it is in part because the able men who founded the place bestowed some thought upon the welfare of the human beings whom they were about to summon to the spot. they did not, it is true, bestow thought enough; but they _thought_ of it, and they made some provision for proper and pleasant life in their proposed town. mr. appleton, who many years ago took the trouble to record these circumstances, mentions that the probable effect of this new kind of industry upon the character of the people was most attentively considered by the founders. in europe, as most of them had personally seen, the operatives were unintelligent and immoral, made so by fifteen or sixteen hours' labor a day, and a beer-shop on every corner. they caused suitable boarding-houses to be built, which were placed under the charge of women known to be competent and respectable. land was assigned and money subscribed for schools, for churches, for a hospital. systematic care was taken to keep away immoral persons, and rules were established, some of which carried the supervision of morals and manners perhaps too far. the consequence was that the daughters of farmers, young women well educated and well-bred, came from all quarters, and found the factory life something more than endurable. but for one thing they would have found it salutary and agreeable. the plague of factory life is the extreme monotony of the employment, and this is aggravated in some mills by high temperature and imperfect ventilation. at that time the laws of health were so little understood that few persons saw any hardship in young girls standing on their feet thirteen, fourteen, fifteen, and even sixteen hours a day! it was considered a triumph when the working-day was reduced to thirteen hours. thirty years ago, after prodigious agitation, the day was fixed at eleven hours. that was too much. it has now been reduced to ten hours; but it is yet to be shown that a woman of average strength and stamina can work in a cotton mill ten hours a day for years at a stretch, without deteriorating in body, in mind, or in character. during the first years the girls would come from the country, work in the mill a few months, or two or three years, and then return to their country homes. thus the injury was less ruinous than it might have been. the high character of the lowell operatives was much spoken of in the early day. some of the boarding-houses contained pianos upon which the boarders played in the evening, and there was a magazine called the "lowell offering," to which they contributed all the articles. these things seemed so astonishing that charles dickens, when he was first in the united states, in , visited lowell to behold the marvels for himself. how changed the world in forty years! few persons now living can remember even the cars of forty years ago, when there were but a few hundred miles of railroad in the united states. the train which conveyed the great novelist from boston to lowell consisted of three cars, a gentlemen's car in which smoking was allowed, a ladies' car in which no one smoked, and "a negro car," which the author describes as a "great, blundering, clumsy chest, such as gulliver put to sea in from the kingdom of brobdingnag." where is now the negro car? it is gone to rejoin its elder brother, the negro pew. the white people's cars he describes as "large, shabby omnibuses," with a red-hot stove in the middle, and the air insufferably close. he happened to arrive at his first factory in lowell just as the dinner hour was over, and the girls were trooping up the stairs as he himself ascended. how strange his comments now appear to us! if we read them by the light of to-day, we find them patronizing and snobbish; but at that day they were far in advance of the feelings and opinions of the comfortable class. he observed that the girls were all well-dressed, extremely clean, with serviceable bonnets, good warm cloaks and shawls, and their feet well protected both against wet and cold. he felt it necessary, as he was writing for english readers, to _apologize_ for their pleasant appearance. "to my thinking," he remarks, "they were not dressed above their condition; for i like to see the humbler classes of society careful of their dress and appearance, and even, if they please, decorated with such little trinkets as come within the compass of their means." he alluded to the "lowell offering," a monthly magazine, "written, edited, and published," as its cover informed the public, "by female operatives employed in the mills." mr. dickens praised this magazine in an extremely ingenious manner. he could not claim that the literature of the work was of a very high order, because that would not have been true. he said:-- "its merits will compare advantageously with a great many english annuals." that is really an exquisite touch of satire. he went on to say:-- "many of its tales inculcate habits of self-denial and contentment, and teach good doctrines of enlarged benevolence. a strong feeling for the beauties of nature, as displayed in the solitudes the writers have left at home, breathes through its pages like wholesome village air.... it has very scant allusion to fine clothes, fine marriages, fine houses, or fine life." i am so happy as to possess a number of the "lowell offering," for august, . it begins with a pretty little story called "a flower dream," which confirms mr. dickens's remarks. there are two or three amiable pieces of poetry, a very moral article upon "napoleon at st. helena," one upon the tyranny of fashion, in which young ladies are advised to "lay aside all glittering ornaments, all expensive trappings," and to present instead the charms of a cultivated mind and good disposition. there is one article in the number which mr. dickens would have enjoyed for its own sake. it is "a letter from susan;" susan being a "mill girl," as she honestly calls herself. she describes the life of the girls in the mill and in the boarding-house. she gives an excellent character both to her companions and to the overseers, one of whom had lately given her a bouquet from his own garden; and the mills themselves, she remarks, were surrounded with green lawns kept fresh all the summer by irrigation, with beds of flowers to relieve their monotony. according to susan, the mills themselves were pleasant places, the rooms being "high, very light, kept nicely whitewashed, and extremely neat, with many plants in the window-seats, and white cotton curtains to the windows." "then," says susan, "the girls dress so neatly, and are so pretty. the mill girls are the prettiest in the city. you wonder how they can keep so neat. why not? there are no restrictions as to the number of pieces to be washed in the boarding-houses. you say you do not see how we can have so many conveniences and comforts at the price we pay for board. you must remember that the boarding-houses belong to the company, and are let to the tenants far below the usual city rents." much has changed in lowell since that day, and it is probable that few mill girls would now describe their life as favorably as susan did in . nevertheless, the present generation of operatives derive much good from the thoughtful and patriotic care of the founders. more requires to be done. a large public park should be laid out in each of those great centres of industry. the abodes of the operatives in many instances are greatly in need of improvement. there is need of half-day schools for children who are obliged to assist their parents. wherever it is possible, there should be attached to every house a piece of ground for a garden. the saying of the old philosopher is as true now as it was in the simple old times when it was uttered: "the way to have good servants is to be a good master." robert owen, cotton-manufacturer. the agitation of labor questions recalls attention to robert owen, who spent a great fortune and a long life in endeavoring to show workingmen how to improve their condition by coöperation. a more benevolent spirit never animated a human form than his; his very failures were more creditable than some of the successes which history vaunts. at the age of ten years, robert owen, the son of a welsh saddler, arrived in london, consigned to the care of an elder brother, to push his fortune. his school-days were over, and there was nothing for him but hard work in some lowly occupation. at the end of six weeks he found a situation as shop-boy in a dry-goods store at stamford, in the east of england; wages, for the first year, his board and lodging; for the second year, eight pounds in addition; and a gradual increase thereafter. in this employment he remained four years, and then, although very happily situated, he made up his mind to return to london to push his fortune more rapidly. being large and forward for his age, a handsome, prompt, active, engaging youth, he soon obtained a situation in a dry-goods store on old london bridge, at a salary of twenty-five pounds a year and his board. but he had to work unreasonably hard, often being obliged to sit up half the night putting away the goods, and sometimes going to bed so tired that he could hardly crawl up stairs. all the clerks had to be in the store ready for business at eight in the morning. this was about the year , when men were accustomed to have their hair elaborately arranged. "boy as i was," he once wrote, "i had to wait my turn for the hair-dresser to powder and pomatum and curl my hair--two large curls on each side and a stiff pigtail. and until this was all nicely done no one thought of presenting himself behind the counter." the lad endured this painful servitude for six months, at the end of which he found a better situation in manchester, the seat of the rising cotton trade, and there he remained until he was nearly nineteen. he appeared to have had no "wild oats" to sow, being at all times highly valued by his employers, and acquiring in their service habits of careful industry, punctuality, and orderliness. he must have been a young man both of extraordinary virtues and more extraordinary abilities; for when he was but nineteen, one of his masters offered to take him as an equal partner, to furnish all the capital, and leave him the whole business in a few years. there was also an agreeable niece in the family, whose affections he had gained without knowing it. "if i had accepted," he says, "i should most likely have married the niece, and lived and died a rich stamford linen-draper." i doubt it. i do not believe that the best shop in christendom could have held him long. when he declined this offer he was already in business for himself manufacturing cotton machinery. this business was a failure, his partner proving incompetent; and he abandoned the enterprise in a few months, taking, as his share of the stock, three cotton-spinning machines. with these he began business for himself as a cotton spinner, hiring three men to work his machines, while he superintended the establishment. he made about thirty dollars a week profit, and was going along at this rate, not ill satisfied with his lot, when he read one morning in the paper an advertisement for a factory manager. he applied for the place in person. "you are too young," said the advertiser. "they used to object to me on that score four or five years ago," was his reply, "but i did not expect to have it brought up now." "why, what age are you?" "i shall be twenty in may next." "how often do you get drunk in the week?" "i never," said owen, blushing, "was drunk in my life." "what salary do you ask?" "three hundred (pounds) a year." "three hundred a year! why, i have had i don't know how many after the place here this morning, and all their askings together would not come up to what you want." "whatever others may ask, i cannot take less. i am making three hundred a year by my own business." he got the place. a few days after, this lad of twenty, who had never so much as entered a large factory in his life, was installed manager of an establishment which employed five hundred people. he conducted himself with consummate prudence and skill. for the first six weeks he went about the building grave, silent, and watchful, using his eyes much and his tongue little, answering questions very briefly, and giving no positive directions. when evening came, and the hands were dismissed, he studied the machinery, the product, and all the secrets of the business. in six weeks he was a competent master, and every one felt that he was a competent master. of large frame, noble countenance, and sympathizing disposition, he won affection, as well as confidence and respect. in six months there was not a better-managed mill in manchester. now began his connection with america, a country to which, by and by, he was to give three valuable sons. while managing this mill he bought the first two bales of american sea island cotton ever imported into england, and he advanced one hundred and seventy pounds to robert fulton, his fellow-boarder, to help him with his inventions. i cannot relate all the steps by which he made his way, while still a very young man, to the ownership of a village of cotton mills in scotland, and to a union with the daughter of david dale, a famous scotch manufacturer and philanthropist of that day. he was but twenty-nine years of age when he found himself at the head of a great community of cotton spinners at new lanark in scotland. here he set on foot the most liberal and far-reaching plans for the benefit of the working people and their children. he built commodious and beautiful school-rooms, in which the children were taught better, in some respects, than the sons of the nobility were taught at eton or harrow. besides the usual branches, he had the little sons and daughters of the people drilled regularly in singing, dancing, military exercises, and polite demeanor. he made one great mistake, due rather to the ignorance of the age than his own: he over-taught the children--the commonest and fatalest of errors to new-born zeal. but his efforts generally for the improvement of the people were wonderfully successful. "for twenty-nine years," as he once wrote to lord brougham, "we did without the necessity for magistrates or lawyers; without a single legal punishment; without any known poors' rates; without intemperance or religious animosities. we reduced the hours of labor, well educated all the children from infancy, greatly improved the condition of the adults, and cleared upward of three hundred thousand pounds profit." having won this great success, he fell into an error to which strong, self-educated men are peculiarly liable,--_he judged other people by himself_. he thought that men in general, if they would only try, could do as well for themselves and others as he had. he thought there could be a new lanark without a robert owen. accustomed all his life to easy success, he was not aware how exceptional a person he was, and he did not perceive that the happiness of the people who worked for him was due as much to his authority as a master as to his benevolence as a man. the consequence was that he devoted the rest of his life to going about the world telling people how much better they would be off if they would stop competing with one another, and act together for their common good. why have one hundred kitchens, one hundred ovens, and one hundred cooks, when the work done in them could be better done in one kitchen, with one oven, by five cooks? this was one question that he asked. here is the steam engine, he would say, doing as much work in great britain as the labor power of two worlds as populous as ours could do without it. yet the mass of the people find life more difficult than it was centuries ago. how is this? such questions robert owen pondered day and night, and the results he reached were three in number:-- . the steam engine necessitates radical changes in the structure of society. . coöperation should take the place of competition. . civilized people should no longer live in cities and separate homes, but in communities of fifteen hundred or two thousand persons each, who should own houses and lands in common, and labor for the benefit of the whole. in spreading abroad these opinions he spent forty of the best years of his life, and the greater part of a princely income. at first, and for a considerable time, such was the magnetism of his presence, and the contagion of his zeal, that his efforts commanded the sympathy, and even the approval, of the ruling classes of england,--the nobility and clergy. but in the full tide of his career as a reformer he deliberately placed himself in opposition to religion. at a public meeting in london he declared in his bland, impressive way, without the least heat or ill-nature, that all the religions of the world, whether ancient or modern, christian or pagan, were erroneous and hurtful. need i say that from that moment the influential classes, almost to a man, dropped him? one of the few who did not was the duke of kent, the father of queen victoria. he remained a steadfast friend to owen as long as he lived. mr. owen founded a community on his own system. its failure was speedy and complete, as all experiments must be which are undertaken ages too soon. he came to america and repeated the experiment. that also failed in a remarkably short period. associated with him in this undertaking was his son, robert dale owen, who has since spent a long and honorable life among us. returning to england, mr. owen continued to labor in the dissemination of his ideas until the year , when he died at the age of eighty-seven. mr. holyoake, author of "the history of cooperation in england," attributes to the teaching of robert owen the general establishment in great britain of coöperative stores, which have been successful. as time goes on it is probable that other parts of his system, may become available; and, perhaps, in the course of time, it may become possible for men to live an associated life in communities such as he suggested. but they will never do it until they can get robert owens at their head, and learn to submit loyally and proudly to the just discipline essential to success where a large number of persons work together. john smedley, stocking-manufacturer. i wonder men in a factory town should ever have the courage to strike; it brings such woe and desolation upon them all. the first few days, the cessation from labor may be a relief and a pleasure to a large number--a holiday, although a dull and tedious holiday, like a sunday without any of the alleviations of sunday--sunday without sunday clothes, sunday bells, sunday church, sunday walks and visits. a painful silence reigns in the town. people discover that the factory bell calling them to work, though often unwelcome, was not a hundredth part as disagreeable as the silence that now prevails. the huge mills stand gaunt and dead; there is no noise of machinery, no puff of steam, no faces at the windows. by the end of the first week the novelty has passed, and the money of some of the improvident families is running low. all are upon short allowance, the problem being to prolong life at the minimum of expense. the man goes without his meat, the mother without her tea, the children without the trifling, inexpensive luxuries with which parental fondness usually treated them. before the end of the second week a good many are hungry, and the workers begin to pine for employment. their muscles are as hungry for exercise as their stomachs are for food. the provision dealers are more and more cautious about giving credit. the bank accounts, representing months or years of self-denying economy, begin to lessen rapidly, and careful fathers see that the bulwarks which they have painfully thrown up to defend their children against the wolf are crumbling away a hundred times faster than they were constructed. if the strike lasts a month, one half the population suffers every hour, and suffers more in mind than in body. anxiety gnaws the soul. men go about pale, gloomy, and despairing; women sit at home suffering even more acutely; until at last the situation becomes absolutely intolerable; and the strikers are fortunate indeed if they secure a small portion of the advance which they claimed. terrible as all this is, i am afraid we must admit that to just such miseries, sometimes rashly encountered, often heroically endured, the workingman owes a great part of the improvement in his condition which has taken place during the last seventy-five years. a strike is like war. it should be the last resort. it should never be undertaken except after long deliberation, and when every possible effort has been made to secure justice by other means. in many instances it is better to submit to a certain degree of injustice than resort to a means of redress which brings most suffering upon the least guilty. does the reader know how the industrial classes were treated in former times? mr. george adcroft, president of an important coöperative organization in england, began life as a coal miner. he has recently given to mr. holyoake, author of the "history of coöperation," some information about the habits and treatment of english miners only forty years ago:-- "they worked absolutely naked, and their daughters worked by their side. he and others were commonly compelled to work sixteen hours a day; and, from week's end to week's end, they never washed either hands or face. one saturday night (he was then a lad of fifteen) he and others had worked till midnight, when there were still wagons at the pit's mouth. they had at last refused to work any later. the foreman told the employer, who waited till they were drawn up to the mouth, and beat them with a stout whip as they came to the surface." so reports mr. holyoake, who could produce, if necessary, from the records of parliamentary investigations, many a ream of similar testimony. in truth, workingmen were scarcely regarded--nay, they were _not_ regarded--as members of the human family. we find proof of this in the ancient laws of every country in europe. in the reign of edward vi. there was a law against idle workmen which shows how they were regarded. any laboring man or servant loitering or living idly for the space of three days could be branded on the breast with the latter v (vagabond) and sentenced to be the slave of the person who arrested him for two years; and that person could "give him bread, water, or small drink, and refuse him meat, and cause him to work by beating, chaining, or otherwise." if he should run away from this treatment, he could be branded on the face with a hot iron with the letter s, and was to be the slave of his master for life. nor does there appear to have been any radical improvement in the condition of the workingman until within the memory of men now alive. when robert owen made his celebrated journey in among the factory towns of great britain, for the purpose of collecting evidence about the employment of children in factories, he gathered facts which his son, who traveled with him, speaks of as being too terrible for belief. "as a rule," says that son (robert dale owen), "we found children of ten years old worked regularly fourteen hours a day, with but half an hour's interval for dinner, which was eaten in the factory.... some mills were run fifteen, and in exceptional cases sixteen hours a day, with a single set of hands; and they did not scruple to employ children of both sexes from the age of eight.... most of the overseers carried stout leather thongs, and we frequently saw even the youngest children severely beaten." this as recently as ! mr. holyoake himself remarks that, in his youth, he never heard one word which indicated a kindly or respectful feeling between employers and employed; and he speaks of the workshops and factories of those days as "charnel-houses of industry." if there has been great improvement, it is due to these causes: the resistance of the operative class; their growth in self-respect, intelligence, and sobriety; and the humanity and wisdom of some employers of labor. the reader has perhaps seen an article lately printed in several newspapers entitled: "strikes and how to prevent them," by john smedley, a stocking manufacturer of manchester, who employs about eleven hundred persons. he is at the head of an establishment founded about the time of the american revolution by his grandfather; and during all this long period there has never been any strike, nor even any disagreement between the proprietors and the work-people. "my ancestors' idea was," says mr. smedley, "that those who ride inside the coach should make those as comfortable as possible who are compelled, from the mere accident of birth, to ride outside." that is the secret of it. mr. smedley mentions some of their modes of proceeding, one of which is so excellent that i feel confident it will one day be generally adopted in large factories. a cotton or woolen mill usually begins work in this country at half-past six, and frequently the operatives live half an hour's walk or ride from it. this obliges many of the operatives, especially family men and women, to be up soon after four in the morning, in order to get breakfast, and be at the mill in time. it is the breakfast which makes the difficulty here. the meal will usually be prepared in haste and eaten in haste; late risers will devour it with one eye on the clock; and of course it cannot be the happy, pleasant thing a breakfast ought to be. but in mr. smedley's mill the people go to work at six without having had their breakfast. at eight the machinery stops, and all hands, after washing in a comfortable wash-room, assemble in what they call the dinner-house, built, furnished, and run by the proprietors. here they find good coffee and tea for sale at two cents a pint, oatmeal porridge with syrup or milk at about ten cents a week; good bread and butter at cost. in addition to these articles, the people bring whatever food they wish from home. the meal is enjoyed at clean, well-ordered tables. the employers keep in their service a male cook and female assistants, who will cook anything the people choose to bring. after breakfast, for fifteen minutes, the people knit, sew, converse, stroll out of doors, or amuse themselves in any way they choose. at half-past eight, the manager takes his stand at a desk in the great dinner-room, gives out a hymn, which the factory choir sings. then he reads a passage from a suitable book,--sometimes from the bible, sometimes from some other book. then there is another hymn by the choir; after which all hands go to work, the machinery starting up again at nine. there is similar accommodation for dinner, and at six work is over for the day. on saturdays the mill is closed at half-past twelve, and the people have the whole afternoon for recreation. all the other rules and arrangements are in harmony with this exquisite breakfast scheme. "we pay full wages," adds mr. smedley, "the hands are smart and effective. no man ever loses a day from drunkenness, and rarely can a hand be tempted to leave us. we keep a supply of dry stockings for those women to put on who come from a distance and get their feet wet; and every overlooker has a stock of waterproof petticoats to lend the women going a distance on a wet night." i would like to cross the sea once more for the purpose of seeing john smedley, and placing wreaths upon the tombs of his grandfather and father. he need not have told us that whenever he goes through the shops all the people recognize him, and that it is a pleasure to him to be so recognized. "i wish," he says, "i could make their lot easier, for, with all we can do, factory life is a hard one." richard cobden, calico printer. an american citizen presented to the english town of bradford a marble statue of richard cobden. it was formally uncovered by mr. john bright, in the presence of the mayor and town council, and a large assembly of spectators. the figure is seven feet in height, and it rests upon a pedestal of scotch granite polished, which bears the name of cobden encircled by an inscription, which summarizes the aims of his public life:-- "free trade, peace and good will among nations." the giver of this costly and beautiful work was mr. g. h. booth, an american partner in a noted bradford firm. unhappily mr. booth did not live to behold his own gift and share in the happiness of this interesting occasion. we ought not to be surprised that an american should have paid this homage to the memory of an english statesman. there are plenty of good americans in this world who were not born in america, and richard cobden was one of them. wherever there is a human being who can intelligently adopt, not as a holiday sentiment merely, but as a sacred principle to be striven for, the inscription borne upon the cobden statue: "free trade, peace, and good will among nations," _there_ is an american. and this i say although we have not yet adopted, as we shall soon adopt, the principle of free trade. cobden was one of the best exemplifications which our times afford of that high quality of a free citizen which we name public spirit. the force of this motive drew him away from a business which yielded a profit of a hundred thousand dollars a year, to spend time, talent, fortune, and life itself, for the promotion of measures which he deemed essential to the welfare of his countrymen. he did this because he could not help doing it. it was his nature so to do. circumstances made him a calico printer, but by the constitution of his mind he was a servant of the state. his father was an english yeoman; that is, a farmer who owned the farm he tilled. during the last century such farmers have become in england fewer and fewer, until now there are scarcely any left; for there is such a keen ambition among rich people in england to own land that a small proprietor cannot hold out against them. a nobleman has been known to give four or five times its value for a farm bordering upon his estate, because in an old country nothing gives a man so much social importance as the ownership of the soil. cobden's father, it appears, lost his property, and died leaving nine children with scarcely any provision for their maintenance; so that richard's first employment was to watch the sheep for a neighboring farmer, and this humble employment he followed on the land and near the residence of the duke of richmond, one of the chiefs of that protectionist party which cobden destroyed. with regard to his education, he was almost entirely self-taught, or, as mr. bright observed, in his most cautious manner:-- "he had no opportunity of attending ancient universities, and availing himself of the advantages, and, i am afraid i must say, in some degree, of suffering from some of the disadvantages, from which some of those universities are not free." this sly satire of the eloquent quaker was received by the men of bradford with cheers; and, indeed, it is true that college education sometimes weakens more than it refines, and many of the masters of our generation have been so lucky as to escape the debilitating process. from tending sheep on his father's farm, he was sent away at ten years of age to a cheap yorkshire boarding-school, similar in character to the dotheboys hall described by dickens many years after in "nicholas nickleby." five miserable years he spent at that school, ill-fed, harshly treated, badly taught, without once going home, and permitted to write to his parents only once in three months. in after life he could not bear to speak of his life at school; nor was he ever quite the genial and happy man he might have been if those five years had been spent otherwise. but here again we see that hardship does not so radically injure a child as unwise indulgence. at fifteen he entered as a clerk into the warehouse of an uncle in london, an uncomfortable place, from which, however, he derived substantial advantages. the great city itself was half an education to him. he learned french in the morning before going to business. he bought cheap and good little books which are thrust upon the sight of every passer-by in cities, and, particularly, he obtained a clear insight into the business of his uncle, who was a wholesale dealer in muslins and calicoes. from clerk he was advanced to the post of commercial traveler, an employment which most keenly gratified his desire to see the world. this was in , before the days of the railroad, when commercial travelers usually drove their own gigs. the ardent cobden accomplished his average of forty miles a day, which was then considered very rapid work. he traversed many parts of great britain, and not only increased his knowledge of the business, but found time to observe the natural beauties of his country, and to inspect its ancient monuments. he spent two or three years in this mode of life, being already the chief support of his numerous and unusually helpless family. at the early age of twenty-four he thought the time had come for him to sell his calicoes and muslins on his own account. two friends in the same business and himself put together their small capitals, amounting to five hundred pounds, borrowed another five hundred, rode to manchester on the top of the coach named the peveril of the peak, boldly asked credit from a wealthy firm of calico manufacturers, obtained it, and launched into business. it proved to be a good thing for them all. in two years the young men were selling fifty or sixty thousand pounds' worth of the old men's calicoes every six months. in after years cobden often asked them how they could have the courage to trust to such an extent three young fellows not worth two hundred pounds apiece. their answer was:-- "we always prefer to trust young men with connections and with a knowledge of their trade, if we know them to possess character and ability, to those who start with capital without these advantages, and we have acted on this principle successfully in all parts of the world." the young firm gained money with astonishing rapidity, one presiding over the warehouse in london, one remaining in manchester, and the other free to go wherever the interests of the firm required. cobden visited france and the united states. he was here in , when he thought the american people were the vainest in the world of their country. he said it was almost impossible to praise america enough to satisfy the people. he evidently did not think much of us then. american men, he thought, were a most degenerate race. and as for the women:-- "my eyes," said he, "have not found one resting place that deserves to be called a wholesome, blooming, pretty woman, since i have been here. one fourth part of the women look as if they had just recovered from a fit of the jaundice, another quarter would in england be termed in a stage of decided consumption, and the remainder are fitly likened to our fashionable women when haggard and jaded with the dissipation of a london season." this was forty-nine years ago. let us hope that we have improved since then. i think i could now find some american ladies to whom no part of this description would apply. after a prosperous business career of a few years he left its details more and more to his partners, and devoted himself to public affairs. richard cobden, i repeat, was a public man by nature. he belonged to what i call the natural nobility of a country; by which i mean the individuals, whether poor or rich, high or low, learned or unlearned, who have a true public spirit, and take care of the public weal. as soon as he was free from the trammels of poverty he fell into the habit of taking extensive journeys into foreign countries, a thing most instructive and enlarging to a genuine nobleman. his first public act was the publication of a pamphlet called, "england, ireland and america," in which he maintained that american institutions and the general policy of the american government were sound, and could safely be followed; particularly in two respects, in maintaining only a very small army and navy, and having no entangling alliances with other countries. "civilization," said the young pamphleteer, "is _peace_; war is barbarism. if the great states should devote to the development of business and the amelioration of the common lot only a small part of the treasure expended upon armaments, humanity would not have long to wait for glorious results." he combated with great force the ancient notion that england must interfere in the politics of the continent; and if england was not embroiled in the horrible war between russia and turkey, she owes it in part to richard cobden. he wrote also a pamphlet containing the results of his observations upon russia, in which he denied that russia was as rich as was generally supposed. he was the first to discover what all the world now knows, that russia is a vast but poor country, not to be feared by neighboring nations, powerful to defend herself, but weak to attack. in a word, he adopted a line of argument with regard to russia very similar to that recently upheld by mr. gladstone. like a true american, he was a devoted friend to universal education, and it was in connection with this subject that he first appeared as a public speaker. mr. bright said in his oration:-- "the first time i became acquainted with mr. cobden was in connection with the great question of education. i went over to manchester to call upon him and invite him to rochdale to speak at a meeting about to be held in the school-room of the baptist chapel in west street. i found him in his counting-house. i told him what i wanted. his countenance lighted up with pleasure to find that others were working in the same cause. he without hesitation agreed to come. he came and he spoke." persons who heard him in those days say that his speaking then was very much what it was afterward in parliament--a kind of conversational eloquence, simple, clear, and strong, without rhetorical flights, but strangely persuasive. one gentleman who was in parliament with him mentioned that he disliked to see him get up to speak, because he was sure that cobden would convince him that his own opinion was erroneous; "and," said he, "a man does not like that to be done." soon after coming upon the stage of active life, he had arrived at the conclusion that the public policy of his country was fatally erroneous in two particulars, namely, the protective system of duties, and the habit of interfering in the affairs of other nations. at that time even the food of the people, their very bread and meat, was shopped at the custom houses until a high duty was paid upon them, for the "protection" of the farmers and landlords. in other words, the whole population of great britain was taxed at every meal, for the supposed benefit of two classes, those who owned and those who tilled the soil. richard cobden believed that the policy of protection was not beneficial even to the protected classes, while it was most cruel to people whose wages were barely sufficient to keep them alive. for several years, aided by mr. bright and many other enlightened men, he labored by tongue and pen, with amazing tact, vigor, persistence, and good temper, to convince his countrymen of this. the great achievement of his life, as all the world knows, was the repeal of those oppressive corn laws by which the duty on grain rose as the price declined, so that the poor man's loaf was kept dear, however abundant and cheap wheat might be in europe and america. it was in a time of deep depression of trade that he began the agitation. he called upon mr. bright to enlist his coöperation, and he found him overwhelmed with grief at the loss of his wife, lying dead in the house at the time. mr. cobden consoled his friend as best he could; and yet even at such a time he could not forget his mission. he said to mr. bright:-- "there are thousands and thousands of homes in england at this moment, where wives, mothers, and children are dying of hunger! now when the first paroxysm of your grief is past, i would advise you to come with me, and we will never rest until the corn laws are repealed." mr. bright joined him. the anti-corn-law-league was formed; such an agitation was made as has seldom been paralleled; but, so difficult is it to effect a change of this kind against _interested_ votes, that, after all, the irish famine was necessary to effect the repeal. as a writer remarks:-- "it was hunger that at last ate through those stone walls of protection!" sir robert peel, the prime minister, a protectionist, as we may say, from his birth, yielded to circumstances as much as to argument, and accomplished the repeal in . when the great work was done, and done, too, with benefit to every class, he publicly assigned the credit of the measure to the persuasive eloquence and the indomitable resolution of richard cobden. mr. cobden's public labors withdrew his attention from his private business, and he became embarrassed. his friends made a purse for him of eighty thousand pounds sterling, with which to set him up as a public man. he accepted the gift, bought back the farm upon which he was born, and devoted himself without reserve to the public service. during our war he was the friend and champion of the united states, and he owed his premature death to his zeal and friendly regard for this country. there was a ridiculous scheme coming up in parliament for a line of fortresses to defend canada against the united states. on one of the coldest days of march he went to london for the sole purpose of speaking against this project. he took a violent cold, under which he sank. he died on that sunday, the second of april, , when abraham lincoln, with a portion of general grant's army, entered the city of richmond. it was a strange coincidence. through four years he had steadily foretold such an ending to the struggle; but though he lived to see the great day he breathed his last a few hours before the news reached the british shore. there is not in great britain, as mr. bright observed, a poor man's home that has not in it a bigger and a better loaf through richard cobden's labors. his great measure relieved the poor, and relieved the rich. it was a good without alloy, as free trade will, doubtless, be to all nations when their irrepressible cobdens and their hungry workmen force them to adopt it. the time is not distant when we, too, shall be obliged, as a people, to meet this question of free trade and protection. in view of that inevitable discussion i advise young voters to study cobden and bright, as well as men of the opposite school, and make up their minds on the great question of the future. henry bessemer. nervous persons who ride in sleeping-cars are much indebted to henry bessemer, to whose inventive genius they owe the beautiful steel rails over which the cars glide so steadily. it was he who so simplified and cheapened the process of making steel that it can be used for rails. nine people in ten, i suppose, do not know the chemical difference between iron and steel. iron is iron; but steel is iron mixed with carbon. but, then, what is carbon? there is no substance in nature of which you can pick up a piece and say, this is carbon. and hence it is difficult to explain its nature and properties. carbon is the principal ingredient in coal, charcoal, and diamond. carbon is not diamond, but a diamond is carbon crystallized. carbon is not charcoal, but in some kinds of charcoal it is almost the whole mass. as crystallized carbon or diamond is the hardest of all known substances, so also the blending of carbon with iron hardens it into steel. the old way of converting iron into steel was slow, laborious, and expensive. in india for ages the process has been as follows: pieces of forged iron are put into a crucible along with a certain quantity of wood. a fire being lighted underneath, three or four men are incessantly employed in blowing it with bellows. through the action of the heat the wood becomes charcoal, the iron is melted and absorbs carbon from the charcoal. in this way small pieces of steel were made, but made at a cost which confined the use of the article to small objects, such as watch-springs and cutlery. the plan pursued in europe and america, until about twenty-five years ago, was similar to this in principle. our machinery was better, and pure charcoal was placed in the crucible instead of wood; but the process was long and costly, and only small pieces of steel were produced at a time. henry bessemer enters upon the scene. in , being then eighteen years of age, he came up to london from a country village in hertfordshire to seek his fortune, not knowing one person in the metropolis. he was, as he has since said, "a mere cipher in that vast sea of human enterprise." he was a natural inventor, of studious and observant habits. as soon as he had obtained a footing in london he began to invent. he first devised a process for copying bas-reliefs on cardboard, by which he could produce embossed copies of such works in thousands at a small expense. the process was so simple that in ten minutes a person without skill could produce a die from an embossed stamp at a cost of one penny. when his invention was complete he thought with dismay and alarm that, as almost all the expensive stamps affixed to documents in england are raised from the paper, any of them could be forged by an office-boy of average intelligence. the english government has long obtained an important part of its revenue by the sale of these stamps, many of which are high priced, costing as much as twenty-five dollars. if the stamp on a will, a deed, or other document is not genuine, the document has no validity. as soon as he found what mischief had been done, he set to work to devise a remedy. after several months' experiment and reflection he invented a stamp which could neither be forged nor removed from the document and used a second time. a large business, it seems, had been done in removing stamps from old parchments of no further use, and selling them to be used again. the inventor called at the stamp office and had an interview with the chief, who frankly owned that the government was losing half a million dollars a year by the use of old stamps; and he was then considering methods of avoiding the loss. bessemer exhibited his invention, the chief feature of which was the perforation of the stamp in such a way that forgery and removal were equally impossible. the commissioner finally agreed to adopt it. the next question was as to the compensation of the young inventor, and he was given his choice either to accept a sum of money or an office for life in the stamp office of four thousand dollars a year. as he was engaged to be married, he chose the office, and went home rejoicing, feeling that he was a made man. nor did he long delay to communicate the joyful news to the young lady. to her also he explained his invention, dwelling upon the fact that a five-pound stamp a hundred years old could be taken off a document and used a second time. "yes," said she, "i understand that; but, surely, if all stamps had a date put upon them they could not at a future time be used again without detection." the inventor was startled. he had never thought of an expedient so simple and so obvious. a lover could not but be pleased at such ingenuity in his affianced bride; but it spoiled his invention! his perforated stamp did not allow of the insertion of more than one date. he succeeded in obviating this difficulty, but deemed it only fair to communicate the new idea to the chief of the stamp office. the result was that the government simply adopted the plan of putting a date upon all the stamps afterwards issued, and discarded bessemer's fine scheme of perforation, which would have involved an expensive and troublesome change of machinery and methods. but the worst of it was that the inventor lost his office, since his services were not needed. nor did he ever receive compensation for the service rendered. thus it was that a young lady changed the stamp system of her country, and ruined her lover's chances of getting a good office. she rendered him, however, and rendered the world, a much greater service in throwing him upon his own resources. they were married soon after, and mrs. bessemer is still living to tell how she married and made her husband's fortune. twenty years passed, with the varied fortune which young men of energy and talent often experience in this troublesome world. we find him then experimenting in the conversion of iron into steel. the experiments were laborious as well as costly, since his idea was to convert at one operation many tons' weight of iron into steel, and in a few minutes. as iron ore contains carbon, he conceived the possibility of making that carbon unite with the iron during the very process of smelting. for nearly two years he was building furnaces and pulling them down again, spending money and toil with just enough success to lure him on to spend more money and toil; experimenting sometimes with ten pounds of iron ore, and sometimes with several hundredweight. his efforts were at length crowned with such success that he was able to make five tons of steel at a blast, in about thirty-five minutes, with comparatively simple machinery, and with a very moderate expenditure of fuel. this time he took the precaution to patent his process, and offered rights to all the world at a royalty of a shilling per hundredweight. his numerous failures, however, had discouraged the iron men, and no one would embark capital in the new process. he therefore began himself the manufacture of steel on a small scale, and with such large profit, that the process was rapidly introduced into all the iron-making countries, and gave mrs. bessemer ample consolation for her early misfortune of being too wise. money and gold medals have rained in upon them. at the french exhibition of mr. bessemer was awarded a gold medal weighing twelve ounces. his process has been improved upon both by himself and others, and has conferred upon all civilized countries numerous and solid benefits. we may say of him that he has added to the resources of many trades a new material. the latest device of henry bessemer, if it had succeeded, would have been a great comfort to the marquis of lorne and other persons of weak digestion who cross the ocean. it was a scheme for suspending the cabin of a ship so that it should swing free and remain stationary, no matter how violent the ship's motion. the idea seems promising, but we have not yet heard of the establishment of a line of steamers constructed on the bessemer principle. we may yet have the pleasure of swinging from new york to liverpool. john bright. manufacturer. forty-five years ago, when john bright was first elected to the british parliament, he spoke thus to his constituents:-- "i am a working man as much as you. my father was as poor as any man in this crowd. he was of your own body entirely. he boasts not, nor do i, of birth, nor of great family distinctions. what he has made, he has made by his own industry and successful commerce. what i have comes from him and from my own exertions. i come before you as the friend of my own class and order, as one of the people." when these words were spoken, his father, jacob bright, a quaker, and the son of a quaker, was still alive, a thriving cotton manufacturer of rochdale, ten miles from manchester. jacob bright had been a "good apprentice," who married one of the daughters of his master, and had been admitted as a partner in his business. he was a man of much force and ability, who became in a few years the practical head of the concern, finally its sole proprietor, and left it to his sons, who have carried it on with success for about half a century longer. [illustration: john bright. august . ] four years ago, on the celebration of john bright's seventieth birthday, he stood face to face with fifteen hundred persons in the employment of his firm, and repeated in substance what he had said once before, that, during the seventy-three years of the firm's existence, there had been, with one brief exception, uninterrupted harmony and confidence between his family and those who had worked for them. he made another remark on that birthday which explains a great deal in his career. it was of particular interest to me, because i have long been convinced that no man can give himself up to the service of the public, with advantage to the public, and safety to himself, unless he is practically free from the burdens and trammels of private business. "i have been greatly fortunate," said mr. bright, "in one respect--that, although connected with a large and increasing and somewhat intricate business, yet i have been permitted to be free from the employments and engagements and occupations of business by the constant and undeviating generosity and kindness of my brother, thomas bright." the tribute was well deserved. certainly, no individual can successfully direct the industry of fifteen hundred persons, and spend six months of the year in london, working night and day as a member of parliament. richard cobden tried it, and brought a flourishing business to ruin by the attempt, and probably shortened his own life. even with the aid rendered him by his brother, mr. bright was obliged to withdraw from public life for three years in order to restore an exhausted brain. john bright enjoyed just the kind of education in his youth which experience has shown to be the best for the development of a leader of men. at fifteen, after attending pretty good quaker schools in the country, where, besides spelling and arithmetic, he learned how to swim, to fish, and to love nature, he came home, went into his father's factory, and became a man of business. he had acquired at school love of literature, particularly of poetry, which he continued to indulge during his leisure hours. you will seldom hear mr. bright speak twenty minutes without hearing him make an apt and most telling quotation from one of the poets. he possesses in an eminent degree the talent of quotation, which is one of the happiest gifts of the popular orator. it is worthy of note that this manufacturer, this man of the people, this manchester man, shows a familiarity with the more dainty, outlying, recondite literature of the world than is shown by any other member of a house composed chiefly of college-bred men. in his early days he belonged to a debating society, spoke at temperance meetings, was an ardent politician, and, in short, had about the sort of training which an american young man of similar cast of mind would have enjoyed. john bright, in fact, is one of that numerous class of americans whom the accident of birth and the circumstances of their lot have prevented from treading the soil of america. in his debating society he had good practice in public speaking, and on all questions took what we may justly call _the quaker side_, _i. e._, the side which he thought had most in it of humanity and benevolence. he sided against capital punishment, against the established church, and defended the principle of equal toleration of all religions. next to mr. gladstone, the most admired speaker in great britain is john bright, and there are those who even place him first among the living orators of his country. his published speeches reveal to us only part of the secret of his power, for an essential part of the equipment of an orator is his bodily attributes, his voice, depth of chest, eye, demeanor, presence. the youngest portrait of him which has been published represents him as he was at the age of thirty-one. if an inch or two could have been added to his stature he would have been as perfect a piece of flesh and blood as can ordinarily be found. his face was strikingly handsome, and bore the impress both of power and of serenity. it was a well-balanced face; there being a full development of the lower portion without any bull-dog excess. his voice was sonorous and commanding; his manner tranquil and dignified. as he was never a student at either university, he did not acquire the cambridge nor the oxford sing-song, but has always spoken the english language as distinctly and naturally as though he were a native american citizen. although of quaker family, and himself a member of the society of friends, he has never used the quaker _thee_ and _thou_, nor persisted in wearing his hat where other men take off theirs. in the house of commons he conforms to the usages of the place, and speaks of "the noble lord opposite," and "my right honorable friend near me," just as though the quakers never had borne their testimony against such vanity. in his dress, too, there is only the faintest intimation of the quaker cut. he is a quaker in his abhorrence of war and in his feeling of the substantial equality of men. he is a quaker in those few sublime principles in which the quakers, two centuries ago, were three centuries in advance of the time. for the benefit of young orators, i will mention also that he has taken excellent care of his bodily powers. as a young man he was a noted cricketer and an enthusiastic angler. at all periods of his life he has played a capital game at billiards. angling, however, has been his favorite recreation, and he has fished in almost all the good streams of the northern part of his native island. nor does he find it necessary to carry a brandy flask with him on his fishing excursions. he mentioned some time ago, at a public meeting, that he had been a tee-totaler from the time when he set up housekeeping thirty-four years before. he said he had in his house no decanters, and, so far as he knew, no wineglasses. edward everett used to say that a speaker's success before an audience depended chiefly upon the thoroughness of his previous preparation. mr. bright has often spoken extempore with great effect, when circumstances demanded it. but his custom is to prepare carefully, and in his earlier days he used frequently to write his speech and learn it by heart. he received his first lesson in oratory from a baptist clergyman of great note, whom he accompanied to a meeting of the bible society, and who afterwards gave an account of their conversation. john bright was then twenty-one years of age. "soon a slender, modest young gentleman came, who surprised me by his intelligence and thoughtfulness. i took his arm on the way to the meeting, and i thought he seemed nervous. i think it was his first public speech. it was very eloquent and powerful, and carried away the meeting, but it was elaborate, and had been committed to memory. on our way back, as i congratulated him, he said that such efforts cost him too dear, and asked me how i spoke so easily. i said that in his case, as in most, i thought it would be best not to burden the memory too much, but, having carefully prepared and committed any portion when special effect was desired, merely to put down other things in the desired order, leaving the wording of them to the moment." the young man remembered this lesson, and acted upon it. he no longer finds it best to learn any portions of his speeches by heart, but his addresses show a remarkable thoroughness of preparation, else they could not be so thickly sown as they are with pregnant facts, telling figures, and apt illustrations. his pudding is too full of plums to be the work of the moment. such aptness of quotation as he displays is sometimes a little too happy to be spontaneous; as when, in alluding to the difference between men's professions out of office and their measures in office, he quoted thomas moore:-- "as bees on flowers alighting cease to hum, so, settling upon places, whigs grow dumb." so also, in referring to the aristocratic composition of the english government, he quoted mr. lowell's "biglow papers":-- "it is something like fulfilling the prophecies when the first families have all the best offices." again, when lamenting the obstacles put in the way of universal education by the rivalries of sect, he produced a great effect in the house of commons by saying:-- "we are, after all, of one religion." and then he quoted in illustration an impressive sentence from william penn, to the effect that just and good souls were everywhere of one faith, and "when death has taken off the mask, they will know one another, though the diverse liveries they wear here make them strangers." no man has less need to quote the brilliant utterances of others than john bright; for he possesses himself the power to speak in epigrams, and to make sentences which remain long in the memory. once in his life he found himself in opposition to the workingmen of his district, and during the excitement of an election he was greeted with hoots and hisses. he made a remark on the platform which all public men making head against opposition would do well to remember:-- "although there are here many of the operative classes who consider me to be their enemy, i would rather have their ill-will now, while defending their interests, than have their ill-will hereafter because i have betrayed them." one of his homely similes uttered thirty years ago, to show the waste and folly of the crimean war, has become a familiar saying in great britain. "some men," said he, "because they have got government contracts, fancy that trade is good, and that war is good for trade. why, it is but endeavoring to keep a dog alive by feeding him with his own tail." this homeliness of speech, when there is strong conviction and massive sense behind it, has a prodigious effect upon a large meeting. once, during his warfare upon the corn laws, he exclaimed:-- "this is not a party question, for men of all parties are united upon it. it is a pantry question--a knife-and-fork question--a question between the working millions and the aristocracy." so in addressing the work-people of his native town, who were on a strike for higher wages at a time when it was impossible for the employers to accede to their demands without ruin, he expressed an obvious truth very happily in saying:-- "neither act of parliament nor act of a multitude can keep up wages." i need scarcely say that no combination of physical and intellectual powers can make a truly great orator. moral qualities are indispensable. there must be courage, sincerity, patriotism, humanity, faith in the future of our race. his quaker training was evidently the most influential fact of his whole existence, for it gave him the key to the moral and political problems of his day. it made him, as it were, the natural enemy of privilege and monopoly in all their countless forms. it suffused his whole being with the sentiment of human equality, and showed him that no class can be degraded without lowering all other classes. he seems from the first to have known that human brotherhood is not a mere sentiment, not a conviction of the mind, but a fact of nature, from which there is no escape; so that no individual can be harmed without harm being done to the whole. when he was a young man he summed up all this class of truths in a sentence:-- "the interests of all classes are so intimately blended that none can suffer without injury being inflicted upon the rest, and the true interest of each will be found to be advanced by those measures which conduce to the prosperity of the whole." feeling thus, he was one of the first to join the movement for free trade. when he came upon the public stage the corn laws, as they were called, which sought to protect the interests of farmers and landlords by putting high duties upon imported food, had consigned to the poor-houses of great britain and ireland more than two millions of paupers, and reduced two millions more to the verge of despair. john bright was the great orator of the movement for the repeal of those laws. after six years of the best sustained agitation ever witnessed in a free country, the farmers and land-owners were not yet convinced. in , however, an event occurred which gave the reasoning of cobden and the eloquence of bright their due effect upon the minds of the ruling class. this event was the irish famine of , which lessened the population of ireland by two millions in one year. this awful event prevailed, though it would not have prevailed unless the exertions of cobden and bright had familiarized the minds of men with the true remedy,--which was the free admission of those commodities for the want of which people were dying. on his seventieth birthday mr. bright justified what he called the policy of . he said to his townsmen:-- "i was looking the other day at one of our wages books of and . i find that the throttle-piecers were then receiving eight shillings a week, and they were working twelve hours a day. i find that now the same class of hands are receiving thirteen shillings a week at ten hours a day--exactly double. at that time we had a blacksmith, whom i used to like to see strike the sparks out. his wages were twenty-two shillings a week. our blacksmiths now have wages of thirty-four shillings, and they only work ten hours." poor men alone know what these figures mean. they know what an amount of improvement in the lot of the industrial class is due to the shortened day, the cheaper loaf, the added shillings. in a word, the effort of john bright's life has been to apply quaker principles to the government of his country. he has called upon ministers to cease meddling with the affairs of people on the other side of the globe, to let turkey alone, to stop building insensate ironclads, and to devote their main strength to the improvement and elevation of their own people. he says to them in substance: you may have an historical monarchy and a splendid throne; you may have an ancient nobility, living in spacious mansions on vast estates; you may have a church hiding with its pomp and magnificence a religion of humility; and yet, with all this, if the mass of the people are ignorant and degraded, the whole fabric is rotten, and is doomed at last to sink into ruin. thomas edward, cobbler and naturalist. the strangest story told for a long time is that of thomas edward, shoemaker and naturalist, to whom the queen of england recently gave a pension of fifty pounds a year. he was not a shoemaker who kept a shop and gave out work to others, but actually worked at the bench from childhood to old age, supporting a very large family on the eight or nine or ten shillings a week that he earned. and yet we find him a member of several societies of naturalists, the linnæan society among others, and an honored pensioner of the queen. his father was a scottish linen weaver, and for some time a private soldier in a militia regiment which was called into active service during the wars with napoleon; and it was while the regiment was stationed at an english sea-port that this remarkable child was born. a few months after, when the waterloo victory had given peace to europe, the regiment was ordered home and disbanded, and this family settled at aberdeen, where the father resumed his former occupation. now the peculiar character of thomas edward began to exhibit itself. he showed an extraordinary fondness for animals, to the sore distress and torment of his parents and their neighbors. it was a taste purely natural, for not only was it not encouraged, it was strongly discouraged by every one who could be supposed to have influence over the boy. he disappeared one day when he was scarcely able to walk, and when he had been gone for some hours he was found in a pig-sty fast asleep, near a particularly savage sow and her pigs. as soon as he could walk well enough his delight was to ramble along the shore and into the country, gathering tadpoles, beetles, frogs, crabs, mice, rats, and spiders, to the horror of his mother, to say nothing of the neighbors, for these awful creatures escaped into houses near by and appeared to the inmates at the most unexpected moments. his parents scolded and whipped him, but his love of animal life was unconquerable, and the only effect of opposing it was to make him more cunning in its gratification. they tied the little fellow by his leg to a table, but he drew the table up near the fire, burnt the rope in halves, and was off for the fields. they hid his coat, but he took his elder brother's coat and ran. then they hid all his clothes, but he slipped on an old petticoat and had another glorious day out of doors, returning with a fever in his veins which brought him to death's door. all these things, and many others like them, happened when he was still a boy under five years of age. recovering from his fever he resumed his old tricks, and brought home one day, wrapped in his shirt, a wasp's nest, which his father took from him and plunged into hot water. between four and five he was sent to school, his parents thinking to keep him out of mischief of this kind. but he had not the least interest in school knowledge, and constantly played truant; and when he did come to school he brought with him all kinds of horrid insects, reptiles, and birds. one morning during prayers a jackdaw began to caw, and as the bird was traced to the ownership of thomas edward, he was dismissed from the school in great disgrace. his perplexed parents sent him to another school, the teacher of which used more vigorous measures to cure him of his propensity, applying to his back an instrument of torture called "the taws." it was in vain. from this second school he was expelled, because some horse-leeches, which he had brought to school in a bottle, escaped, crept up the legs of the other boys, and drew blood from them. "i would not take him back for twenty pounds!" said the schoolmaster in horror. a third time his father put him at school; and now he experienced the ill consequences of having a bad name. a centipede was found upon another boy's desk, and he was of course suspected of having brought it into the school-room. but it so happened that on this one occasion he was innocent; it was another boy's centipede; and thomas denied the charge. the schoolmaster whipped him severely for the supposed falsehood, and sent him away saying:-- "go home, and tell your father to get you on board a man-of-war, as that is the best school for irreclaimables such as you." he went home and declared he would go to no more schools, but would rather work. he had now reached the mature age of six years, and had been turned out of school three times, without having learned to write his own name. soon after, he went to work in a tobacco factory on the river don, a short distance out of aberdeen, and there for two happy years he was free to employ all his leisure time in investigating animated nature around him. his love of natural history grew with his growth and strengthened with his strength, so that by the time he had completed his eighth year he was familiarly acquainted with the animals of that region, and had the most lively admiration for the more interesting specimens. he watched with delight the kingfisher, and loved to distinguish the voices of the different birds. but his parents objecting to the tobacconist's trade, he was apprenticed about his ninth year to a shoemaker,--a violent, disreputable character, who made ruthless war upon the lad's birds and reptiles, searching his pockets for them, and killing them whenever found. the lad bore this misery for three years, and then his patience being exhausted, and having in his pocket the sum of seven pence, he ran away and walked a hundred miles into the country to the house of one of his uncles. his uncle received him kindly, entertained him a day or two, and gave him eighteen pence, upon which the boy returned home, and made a bargain with his master by which he received small wages and had complete control of his leisure time. at eighteen we may regard him as fairly launched upon life, a journeyman shoemaker, able to earn in good times nine shillings a week by laboring from six in the morning till nine at night. at that time all mechanics worked more hours than they do at present, and particularly shoemakers, whose sedentary occupation does not expend vitality so rapidly as out-of-door trades. and what made his case the more difficult was, he was a thorough-going scotchman, and consequently a strict observer of sunday. confined though he was to his work fifteen hours a day, he abstained on principle from pursuing his natural studies on the only day he could call his own. he was a night-bird, this thomas edward; and as in scotland the twilight lasts till ten in the evening and the day dawns at three in the morning, there were some hours out of the twenty-four which he could employ, and did employ, in his rambles. at twenty-three he fell in love with a pretty girl, and married her, his income being still but nine and sixpence a week. his married life was a happy one, for his wife had the good sense to make no opposition to his darling pursuits, and let him fill their cottage and garden with as many creatures as he chose, not even scolding him for his very frequent absences during the night. some one asked her recently about this, and her reply was:-- "weel, he took such an interest in beasts that i didna compleen. shoemakers were then a very drucken set, but his beasts keepit him frae them. my mon's been a sober mon all his life, and he never negleckit his wark. sae i let him be."-- children were born to them, eleven in all, and yet he found time to learn to write, to read some books, and to increase constantly his knowledge of nature. in order to procure specimens for his collection, he bought an old shot-gun for a sum equal to about a dollar,--such a battered old piece that he had to tie the barrel to the stock with a piece of string. a cow's horn served for his powder; he measured his charge with a tobacco pipe, and carried his shot in a paper-bag. about nine in the evening, carrying his supper with him, he would start out and search the country round for animals and rare plants as long as he could see; then eat his supper and lie down and sleep till the light returned, when he would continue his hunting till it was time for work. many a fight he had in the darkness with badgers and pole-cats. when he had thus been employed eight or nine years, his collection contained two thousand specimens of animals and two thousand plants, all nicely arranged in three hundred cases made with his own hands. upon this collection he had founded hopes of getting money upon which to pursue his studies more extensively. so he took it to aberdeen, six cart loads in all, accompanied by the whole family,--wife and five children. it needs scarcely to be said that his collection did not succeed, and he was obliged to sell the fruit of nine years' labor for twenty pounds. nothing daunted, he returned to his cobbler's stall, and began again to collect, occasionally encouraged by a neighboring naturalist, and sometimes getting a little money for a rare specimen. often he tried to procure employment as a naturalist, but unsuccessfully, and as late as we find him writing thus:-- "as a last and only remaining resource, i betook myself to my old and time-honored friend, a friend of fifty years' standing, who has never yet forsaken me nor refused help to my body when weary, nor rest to my limbs when tired--my well-worn cobbler's stool. and although i am now like a beast tethered to his pasture, with a portion of my faculties somewhat impaired, i can still appreciate and admire as much as ever the beauties and wonders of nature as exhibited in the incomparable works of our adorable creator." these are cheerful words to come from an old man who has enriched the science of his country by additions to its sources of knowledge. in another letter, written a year or two since, he says:-- "had the object of my life been money instead of nature, i have no hesitation in saying that by this time i would have been a rich man. but it is not the things i have done that vex me so much as the things i have not done. i feel that i could have accomplished so much more. i had the will, but i wanted the means." it is in this way that such men feel toward the close of their lives. thomas edward still lives, in his sixty-seventh year, at banff, in scotland, rich in his pension of fifty pounds a year, which is more than twice as much as the income he had when he supported by his labor a wife and eleven children. even his specimens now command a price, and he is every way a prosperous gentleman. it seems a pity that such men cannot have their precious little fifty pounds to begin with, instead of to end with. but who could pick them out? what mortal eye can discern in a man the _genuine_ celestial fire before he has proved its existence by the devotion of a lifetime to his object? and even if it could be discerned in a young man, the fifty pounds a year might quench it. robert dick, baker and naturalist. the most northern county of scotland is caithness, a wild region of mountain, marsh, and rock-ribbed headlands, in which the storms of the atlantic have worn every variety of fantastic indentation. much of the land has been reclaimed in modern days by rich proprietors. there are manufactures of linen, wool, rope, and straw, besides important fisheries; so that forty thousand people now find habitation and subsistence in the county. there are castles, too, ancient and modern,--some in ruins, some of yesterday,--the summer home of wealthy people from the south. the coast is among the most picturesque in the world, bearing a strong resemblance to the coast of maine. the reader, perhaps, has never seen the coast of maine. then let him do so speedily, and he will know, as he sails along its bold headlands, and its seamed walls of rock rising here and there into mountains, how the coast of caithness looked to one of the noblest men that ever lived in it, robert dick, baker of thurso. thurso is the most northern town of this most northern county. it is situated on thurso bay, which affords a good harbor, and it has thus grown to be a place of three or four thousand inhabitants. from this town the orkney islands can be seen, and a good walker can reach in a day's tramp dunnet head, the lofty promontory which ends the island. here lived, labored, studied, and died, robert dick, a man whose name should never be pronounced by intelligent men but with respect. he did not look like a hero. when the boys of the town saw him coming out of his baker's shop, in a tall stove-pipe hat, an old-fashioned dress coat and jean trousers, they used to follow him to the shore, and watch him as he walked along it with his eyes fixed upon the ground. suddenly he would stop, fall upon his hands and knees, crawl slowly onward, and then with one hand catch something on the sand; an insect, perhaps. he would stick it upon a pin, put it in his hat, and go on his way; and the boys would whisper to one another that there was a mad baker in thurso. once he picked up a nut upon the beach, and said to his companion:-- "that has been brought by the ocean current and the prevailing winds all the way from one of the west india islands." he made the most astonishing journeys about that fag end of the universe in the pursuit of knowledge. we read of his walking thirty-two miles in a soaking rain to the top of a mountain, and bringing home only a plant of white heather. on another day he walked thirty-six miles to find a peculiar kind of fern. again he walked for twenty-four hours in hail, rain, and wind, reaching home at three o'clock in the morning. but at seven he was up and ready for work as usual. he carried heavy loads, too, when he went searching for minerals and fossils. in one of his letters we read:-- "shouldering an old poker, a four-pound hammer, and with two chisels in my pocket, i set out.... what hammering! what sweating! coat off; got my hands cut to bleeding." in another letter he speaks of having "three pounds of iron chisels in his trousers pocket, a four-pound hammer in one hand and a fourteen-pound sledge-hammer in the other, and his old beaver hat filled with paper and twine." but who and what was this man, and why was he performing these laborious journeys? robert dick, born in , was the son of an excise officer, who gave his children a hard stepmother when robert was ten years old. the boy's own mother, all tenderness and affection, had spoiled him for such a life as he now had to lead under a woman who loved him not, and did not understand his unusual cast of character, his love of nature, his wanderings by the sea, his coming home with his pockets full of wet shells and his trousers damaged by the mire. she snubbed him; she whipped him. he bore her ill treatment with wonderful patience; but it impaired the social side of him forever. nearly fifty years after he said to one of his few friends:-- "all my naturally buoyant, youthful spirits were broken. to this day i feel the effects. i cannot shake them off. it is this that still makes me shrink from the world." at thirteen he escaped from a home blighted by this woman, and went apprentice to a baker; and when he was out of his time served as a journeyman for three years; then set up a small business for himself in thurso. it was a very small business indeed; for at that day bread was a luxury which many people of caithness only allowed themselves on sundays; their usual fare being oatmeal. he was a baker all the days of his life, and his business never increased so as to oblige him to employ even a baker's boy. he made his bread, his biscuit, and his gingerbread without any assistance, and when it was done, it was sold in his little shop by an old housekeeper, who lived with him till he died. the usual course of his day was this: he was up in the morning very early, at any time from three to six, according to his plans for the after part of the day. he kneaded his bread, worked the dough into loaves, put the whole into the oven, waited till it was baked, and drew it out. his work was then usually done for the day. the old housekeeper sold it as it was called for, and, in case her master did not get home in time, she could set the sponge in the evening. usually, he could get away from the bake-shop soon after the middle of the day, and he had then all the afternoon, the evening, and the night for studying nature in caithness. his profits were small, but his wants were few, and during the greater part of his life he was able to spare a small sum per annum for the purchase of books. if this man had enjoyed the opportunities he would have had but for his mother's death, he might have been one of the greatest naturalists that ever lived. nature had given him every requisite: a frame of iron, scotch endurance, a poet's enthusiasm, the instinct of not believing anything in science till he was _sure_ of it, till he had put it to the test of repeated observation and experiment. although a great reader, he derived most of his knowledge directly from nature's self. he began by merely picking up shells, as a child picks them up, because they were pretty; until, while still a lad, he had a very complete collection all nicely arranged in a cabinet and labeled. youth being past, the shy and lonely young man began to study botany, which he pursued until he had seen and felt everything that grew in caithness. next he studied insects, and studied with such zeal that in nine months he had collected, of beetles alone, two hundred and fifty-six specimens. there are still in the thurso museum two hundred and twenty varieties of bees, and two hundred and forty kinds of butterflies, collected by him. early in life he was powerfully attracted to astronomy, and read everything he could find upon the subject. but he was one of those students whom books alone can never satisfy; and as a telescope was very far beyond his means he was obliged to devote himself to subjects more within his own reach. he contrived out of his small savings to buy a good microscope, and found it indispensable. geology was the subject which occupied him longest and absorbed him most. he pursued it with untiring and intelligent devotion for thirty years. he found the books full of mistakes, because, as he said, so many geologists study nature from a gig and are afraid to get a little mud on their trousers. "when," said he, "i want to know what a rock is, i go to it; i hammer it; i dissect it. i then know what it really is.... the science of geology! no, no; we must just work patiently on, _collect facts_, and in course of time geology may develop into a science." i suppose there never was a man whose love of knowledge was more disinterested. he used to send curious specimens to hugh miller, editor of "the witness" as well as a geologist, and mr. miller would acknowledge the gifts in his paper; but robert dick entreated him not to do so. "i am a quiet creature," he wrote, "and do not like to see myself in print at all. so leave it to be understood who found the old bones, and let them guess who can." as long as he was in unimpaired health he continued this way of life cheerfully enough, refusing all offers of assistance. his brother-in-law once proposed to send him a present of whiskey. "no," said he in reply, "spirits never enter this house save when i cannot help it." his brother-in-law next offered to send him some money. he answered:-- "god grant you more sense! i want no sovereigns. it's of no use sending anything down here. nothing is wanted. delicacies would only injure health. _hardy_ is the word with working people. pampering does no good, but much evil." and yet the latter days of this great-souled man were a woeful tragedy. he was the best baker in the place, gave full weight, paid for his flour on the day, and was in all respects a model of fair dealing. but his trade declined. competition reduced his profits and limited his sales. when the great split occurred in scotland between the old and the free church, he stuck to the old, merely saying that the church of his forefathers was good enough for him. but his neighbors and customers were zealous for the free church; and one day, when the preacher aimed a sermon at him for taking his walks on sunday, he was offended, and rarely went again. and so, for various reasons, his business declined; some losses befell him; and he injured his constitution by exposure and exhausting labors in the study of geology. there were rich and powerful families near by who knew his worth, or would have known it if they had themselves been worthy. they looked on and saw the noblest heart in scotland break in this unequal strife. they should have set him free from his bake-shop as soon as he had given proof of the stuff he was made of. he was poet, artist, philosopher, hero, and they let him die in his bakehouse in misery. after his death they performed over his body the shameful mockery of a pompous funeral, and erected in his memory a paltry monument, which will commemorate their shame as long as it lasts. his name has been rescued from oblivion by the industry and tact of samuel smiles, who, in writing his life, has revealed to us a rarer and higher kind of man than robert burns. john duncan, weaver and botanist. many young men ask nowadays what is the secret of "success." it were better to inquire also how to do without success, since that is the destiny of most of us, even in the most prosperous communities. could there be imagined a more complete "failure" than this john duncan, a scottish weaver, always very poor, at last a pauper, short-sighted, bent, shy, unlettered, illegitimate, dishonored in his home, not unfrequently stoned by the boys of the roadside, and in every particular, according to the outward view, a wretched fag-end of human nature! yet, redeemed and dignified by the love of knowledge, he passed, upon the whole, a joyous and even a triumphant life. he had a pursuit which absorbed his nobler faculties, and lifted him far above the mishaps and inconveniences of his lowly lot. the queen of his country took an interest in his pursuits, and contributed to the ease of his old age. learned societies honored him, and the illustrious charles darwin called him "my fellow botanist." [illustration: john duncan] the mother of john duncan, a "strong, pretty woman," as he called her, lived in a poor tenement at stonehaven, on the scottish coast, and supported herself by weaving stockings at her own home, and in the summer went into the harvest field. he always held his mother in honor and tenderness, as indeed he ought, for she stood faithfully by the children she ought not to have borne. as a boy the future botanist developed an astonishing faculty of climbing. there was a famous old castle upon the pinnacle of a cliff, inaccessible except to cats and boys. he was the first to gain access to the ancient ruin, and after him the whole band of boys explored the castle, from the deep dungeons to the topmost turret. his first employment led him directly to what became a favorite pursuit of his lifetime. by way of adding to the slender gains of his mother, he extracted the white pith from certain rushes of the region, which made very good lamp-wicks for the kind of lamps then in use in scotland. these wicks of pith he sold about the town in small penny bundles. in order to get his supply of rushes he was obliged to roam the country far and wide, and along the banks of streams. when he had gathered as many as he could carry he would bring them home to be stripped. to the end of his days, when he knew familiarly every plant that grew in his native land, he had a particular fondness for all the varieties of rush, and above all for the kind that gave him his first knowledge. then he went to a farmer's to tend cattle, and in this employment he experienced the hard and savage treatment to which hired boys were so frequently subjected at that day. drenched with rain after tending his herd all day, the brutal farmer would not permit him to go near the fire to dry his clothes. he had to go to his miserable bed in an out-house, where he poured the water from his shoes, and wrung out his wet clothes as dry as he could. in that foggy climate his garments were often as wet in the morning as he left them in the evening, and so days would pass without his having a dry thread upon him. but it did not rain always. frequently his herd was pastured near the old castle, which, during the long summer days, he studied more intelligently, and in time learned all about its history and construction. and still he observed the flowers and plants that grew about his feet. it seemed natural to him to observe them closely and to learn their names and uses. in due time he was apprenticed to a weaver. this was before the age of the noisy, steaming factory. each weaver then worked at home, at his own loom, and could rent, if he chose, a garden and a field, and keep a cow, and live a man's life upon his native soil. again our poor, shy apprentice had one of the hardest of masters. the boy was soon able to do the work of a man, and the master exacted it from him. on saturdays the loom was usually kept going till midnight, when it stopped at the first sound of the clock, for this man, who had less feeling for a friendless boy than for a dog or a horse, was a strict sabbatarian. in the depth of the scotch winter he would keep the lad at the river-side, washing and wringing out the yarn, a process that required the arms to be bare and the hands to be constantly wet. his hands would be all chilblains and frost-bitten. but again we may say it was not always winter. in the most dismal lot there are gleams of sunshine. the neighbors pitied and comforted him. his tyrant's wife was good to him as far as she dared. it was she, indeed, who inspired him with the determination to learn to read, and another friendly woman gave him regular instruction. he was sixteen years old when he learned his alphabet. a school-girl, the daughter of another weaver, would come into his shop to hear him read his lesson, and tell him how to pronounce the hard words. this bright, pretty girl of twelve would take her seat on the loom beside the bashful, lanky boy, who, with the book close to his eyes and his finger on the page, would grope his way through the paragraph. other children helped him, and he was soon able to get the meanings from the few books at his command. his solitary walks were still cheered by his observation of nature, although as yet he did not know there was such a thing as a science of botany. he could give no account of the interest he took in plants, except that he "loved the pretty little things," and liked to know their names, and to classify in his rude way those that were alike. the exactions of his despot wore out at length even his astonishing patience. he ran away at twenty, and entered upon the life which he lived all the rest of his days, that of a weaver, wandering about scotland according to his need of work. at this period he was not the possessor of a single book relating to his favorite pursuit, and he had never seen but one, an old-fashioned work of botany and astrology, of nature and superstition, by the once famous culpepper. it required extra work for months, at the low wages of a hand-loom weaver, to get the money required for the purchase of this book, about five dollars. the work misled him in many ways, but it contained the names and properties of many of his favorite herbs. better books corrected these errors by and by, and he gradually gathered a considerable library, each volume won by pinching economy and hard labor. the sorrow of his life was his most woeful, disastrous marriage. his wife proved false to him, abandoned his home and their two daughters, and became a drunken tramp. every now and then she returned to him, appealing to his compassion for assistance. i think charles dickens must have had john duncan's case in his mind when he wrote those powerful scenes of the poor man cursed with a drunken wife in "hard times." but the more miserable his outward life, the more diligently he resorted for comfort to his darling plants. for many years he groped in the dark; but at length he was put upon the right path by one of those accomplished gardeners so common in scotland, where the art of gardening is carried to high perfection. he always sought the friendship of gardeners wherever he went. nevertheless he was forty years old before he became a scientific botanist. during the rest of his life of forty-four years, besides pursuing his favorite branch, he obtained a very considerable knowledge of the kindred sciences and of astronomy. being obliged to sell his watch in a time of scarcity, he made for himself a pocket sun-dial, by which he could tell the time to within seven or eight minutes. during this period steam was gaining every year upon hand power; his wages grew less and less; and, as his whole heart was in science, he had no energy left for seeking more lucrative employment. when he was past eighty-three he would walk twelve miles or more to get a new specimen, and hold on his way, though drenched with a sudden storm. at length, old age and lack of work reduced him to actual suffering for the necessaries of life. mr. william jolly, a contributor to periodicals, heard his story, sought him out, and found him so poor as to be obliged to accept out-door relief, of which the old man was painfully ashamed. he published a brief history of the man and of his doings in the newspapers. "the british people," says voltaire, "may be very stupid, but they know how to give." money rained down upon the old philosopher, until a sum equal to about sixteen hundred dollars had reached him, which abundantly sufficed for his maintenance during the short residue of his life. for the first time in fifty years he had a new and warm suit of clothes, and he again sat down by his own cheerful fire, an independent man, as he had been all his life until he could no longer exercise his trade. he died soon after, bequeathing the money he had received for the foundation of scholarships and prizes for the encouragement of the study of natural science among the boys and girls of his country. his valuable library, also, he bequeathed for the same object. james lackington, second-hand bookseller. it would seem not to be so very difficult a matter to buy an article for fifty cents and sell it for seventy-five. business men know, however, that to live and thrive by buying and selling requires a special gift, which is about as rare as other special gifts by which men conquer the world. in some instances, it is easier to make a thing than to sell it, and it is not often that a man who excels in the making succeeds equally well in the selling. general george p. morris used to say:-- "i know a dozen men in new york who could make a good paper, but among them all i do not know one who could sell it." the late governor morgan of new york had this talent in a singular degree even as a boy. his uncle sent him to new york, to buy, among other things, two or three hundred bushels of corn. he bought two cargoes, and sold them to advantage in hartford on his way from the stage office to his uncle's store, and he kept on doing similar things all his life. he knew by a sort of intuition when it was safe to buy twenty thousand bags of coffee, or all the coffee there was for sale in new york, and he was very rarely mistaken; he had a genius for buying and selling. i have seen car-boys and news-boys who had this gift. there are boys who will go through a train and hardly ever fail to sell a book or two. they improve every chance. if there is a passenger who wants a book, or can be made to think he wants one, the boy will find him out. now james lackington was a boy of that kind. in the preface to the memoirs which he wrote of his career he described himself as a person "who, a few years since, began business with five pounds, and now sells one hundred thousand volumes annually." but in fact he did not begin business with five pounds, but with nothing at all. he was the son of a drunken shoemaker who lived in an english country town, and he had no schooling except a few weeks at a dame's school, at twopence a week. he had scarcely learned his letters at that school when his mother was obliged to take him away to help her in tending his little brothers and sisters. he spent most of his childhood in doing that, and, as he remarks, "in running about the streets getting into mischief." when he was ten years old he felt the stirring of an inborn genius for successful traffic. he noticed, and no doubt with the hungry eyes of a growing boy, an old pie-man, who sold his pies about the streets in a careless, inefficient way, and the thought occurred to him that, if he had pies to sell, he could sell more of them than the ancient pie-man. he went to a baker and acquainted him with his thoughts on pie-selling, and the baker soon sent him out with a tray full of pies. he showed his genius at once. the spirited way in which he cried his pies, and his activity in going about with them, made him a favorite with the pie-buyers of the town; so that the old pie-man in a few weeks lost all his business, and shut up his shop. the boy served his baker more than a year, and sold so many pies and cakes for him as to save him from impending bankruptcy. in the winter time he sold almanacs with such success that the other dealers threatened to do him bodily mischief. but this kind of business would not do to depend on for a lifetime, and therefore he was bound apprentice to a shoemaker at the age of fourteen years, during which a desire for more knowledge arose within him. he learned to read and write, but was still so ashamed of his ignorance that he did not dare to go into a bookstore because he did not know the name of a single book to ask for. one of his friends bought for him a little volume containing a translation from the greek philosopher epictetus, a work full of wise maxims about life and duty. then he bought other ancient authors, plato, plutarch, epicurus, and others. he became a sort of methodist philosopher, for he heard the methodist preachers diligently on sundays, and read his greek philosophy in the evenings. he tells us that the account of epicurus living in his garden upon a halfpenny a day, and considering a little cheese on his bread as a great treat, filled him with admiration, and he began forthwith to live on bread and tea alone, in order to get money for his books. after ending his apprenticeship and working for a short time as a journeyman, he married a buxom dairymaid, with whom he had been in love for seven years. it was a bold enterprise, for when they went to their lodgings after the wedding they searched their pockets carefully to discover the state of their finances, and found that they had one halfpenny to begin the world with. they had laid in provisions for a day or two, and they had work by which to procure more, so they began their married life by sitting down to work at shoemaking and singing together the following stanza: "our portion is not large indeed, but then how little do we need! for nature's wants are few. in this the art of living lies, to want no more than may suffice, and make that little do." they were as happy as the day was long. twenty times, reports this jolly shoemaker, he and his wife sang an ode by samuel wesley, beginning:-- "no glory i covet, no riches i want, ambition is nothing to me; the one thing i beg of kind heaven to grant is a mind independent and free." they needed their cheerful philosophy, for all they had to spend on food and drink for a week was a sum about equal to one of our dollars. even this small revenue grew smaller, owing to the hard times, and poor james lackington saw his young wife pining away under insufficient food and sedentary employment. his courage again saved him. after enduring extreme poverty for three years, he got together all the money he could raise, gave most of it to his wife, and set out for london, where he arrived in august, , with two and sixpence in his pocket. it was a fortunate move for our brave shoemaker. he obtained work and good wages at once, soon sent for his wife, and their united earnings more than supplied their wants. a timely legacy of ten pounds from his grandfather gave them a little furniture, and he became again a frequenter of second-hand bookstores. he could scarcely resist the temptation of a book that he wanted. one christmas eve he went out with money to buy their christmas dinner, but spent the whole sum for a copy of young's "night thoughts." his wife did not relish this style of christmas repast. "i think," said he to his disappointed spouse, "that i have acted wisely; for had i bought a dinner we should have eaten it to-morrow, and the pleasure would have been soon over; but should we live fifty years longer we shall have the 'night thoughts' to feast upon." it was his love of books that gave him abundant christmas dinners for the rest of his life. having hired a little shop in which to sell the shoes made by himself and his wife, it occurred to him that he could employ the spare room in selling old books, his chief motive being to have a chance to read the books before he sold them. beginning with a stock of half a hundred volumes, chiefly of divinity, he invested all his earnings in this new branch, and in six months he found his stock of books had increased fivefold. he abandoned his shoemaking, moved into larger premises, and was soon a thriving bookseller. he was scrupulous not to sell any book which he thought calculated to injure its readers, although about this time he found the methodist society somewhat too strict for him. he makes a curious remark on this subject:-- "i well remember," he says, "that some years before, mr. wesley told his society at bristol, in my hearing, that he could never keep a bookseller six months in his flock." his trade increased with astonishing rapidity, and the reason was that he knew how to buy and sell. he abandoned many of the old usages and traditions of the book trade. he gave no credit, which was itself a startling innovation; but his master-stroke was selling every book at the lowest price he could afford, thus giving his customers a fair portion of the benefit of his knowledge and activity. he appears to have begun the system by which books have now become a part of the furniture of every house. he bought with extraordinary boldness, spending sometimes as much as sixty thousand dollars in an afternoon's sale. as soon as he began to live with some liberality kind friends foretold his speedy ruin. or, as he says:-- "when by the advice of that eminent physician, dr. lettsom, i purchased a horse, and saved my life by the exercise it afforded me, the old adage, 'set a beggar on horseback and he'll ride to the devil,' was deemed fully verified." but his one horse became two horses, and his chaise a chariot with liveried servants, in which vehicle, one summer, he made the round of the places in which he had lived as a shoemaker, called upon his old employers, and distributed liberal sums of money among his poor relations. so far from being ashamed of his business, he caused to be engraved on all his carriage doors the motto which he considered the secret of his success:-- small profits do great things. in his old age he rejoined his old friends the methodists, and he declares in his last edition that, if he had never heard the methodists preach, in all probability he should have remained through life "a poor, ragged, dirty cobbler." horace greeley's start. i have seldom been more interested than in hearing horace greeley tell the story of his coming to new york in , and gradually working his way into business there. he was living at the age of twenty years with his parents in a small log-cabin in a new clearing of western pennsylvania, about twenty miles from erie. his father, a yankee by birth, had recently moved to that region and was trying to raise sheep there, as he had been accustomed to do in vermont. the wolves were too numerous there. it was part of the business of horace and his brother to watch the flock of sheep, and sometimes they camped out all night, sleeping with their feet to the fire, indian fashion. he told me that occasionally a pack of wolves would come so near that he could see their eyeballs glare in the darkness and hear them pant. even as he lay in the loft of his father's cabin he could hear them howling in the fields. in spite of all their care, the wolves killed in one season a hundred of his father's sheep, and then he gave up the attempt. the family were so poor that it was a matter of doubt sometimes whether they could get food enough to live through the long winter; and so horace, who had learned the printer's trade in vermont, started out on foot in search of work in a village printing-office. he walked from village to village, and from town to town, until at last he went to erie, the largest place in the vicinity. there he was taken for a runaway apprentice, and certainly his appearance justified suspicion. tall and gawky as he was in person, with tow-colored hair, and a scanty suit of shabbiest homespun, his appearance excited astonishment or ridicule wherever he went. he had never worn a good suit of clothes in his life. he had a singularly fair, white complexion, a piping, whining voice, and these peculiarities gave the effect of his being wanting in intellect. it was not until people conversed with him that they discovered his worth and intelligence. he had been an ardent reader from his childhood up, and had taken of late years the most intense interest in politics and held very positive opinions, which he defended in conversation with great earnestness and ability. a second application at erie procured him employment for a few months in the office of the erie "gazette," and he won his way, not only to the respect, but to the affection, of his companions and his employer. that employer was judge j. m. sterrett, and from him i heard many curious particulars of horace greeley's residence in erie. as he was only working in the office as a substitute, the return of the absentee deprived him of his place, and he was obliged to seek work elsewhere. his employer said to him one day:-- "now, horace, you have a good deal of money coming to you; don't go about the town any longer in that outlandish rig. let me give you an order on the store. dress up a little, horace." the young man looked down at his clothes as though he had never seen them before, and then said, by way of apology:-- "you see, mr. sterrett, my father is on a new place, and i want to help him all i can." in fact, upon the settlement of his account at the end of his seven months' labor, he had drawn for his personal expenses six dollars only. of the rest of his wages he retained fifteen dollars for himself, and gave all the rest, amounting to about a hundred and twenty dollars, to his father, who, i am afraid, did not make the very best use of all of it. with the great sum of fifteen dollars in his pocket, horace now resolved upon a bold movement. after spending a few days at home, he tied up his spare clothes in a bundle, not very large, and took the shortest road through the woods that led to the erie canal. he was going to new york, and he was going cheap! a walk of sixty miles or so, much of it through the primeval forest, brought him to buffalo, where he took passage on the erie canal, and after various detentions, he reached albany on a thursday morning just in time to see the regular steamboat of the day move out into the stream. at ten o'clock on the same morning he embarked on board of a tow-boat, which required nearly twenty-four hours to descend the river, and thus afforded him ample time to enjoy the beauty of its shores. on the th of august, , about sunrise, he set foot in the city of new york, then containing about two hundred thousand inhabitants, one sixth of its present population. he had managed his affairs with such strict economy that his journey of six hundred miles had cost him little more than five dollars, and he had ten left with which to begin life in the metropolis. this sum of money and the knowledge of the printer's trade made up his capital. there was not a person in all new york, so far as he knew, who had ever seen him before. his appearance, too, was much against him, for although he had a really fine face, a noble forehead, and the most benign expression i ever saw upon a human countenance, yet his clothes and bearing quite spoiled him. his round jacket made him look like a tall boy who had grown too fast for his strength; he stooped a little and walked in a loose-jointed manner. he was very bashful, and totally destitute of the power of pushing his way, or arguing with a man who said "no" to him. he had brought no letters of recommendation, and had no kind of evidence to show that he had even learned his trade. the first business was, of course, to find an extremely cheap boarding-house, as he had made up his mind only to try new york as an experiment, and, if he did not succeed in finding work, to start homeward while he still had a portion of his money. after walking awhile he went into what looked to him like a low-priced tavern, at the corner of wall and broad streets. "how much do you charge for board?" he asked the bar-keeper, who was wiping his decanters and putting his bar in trim for the business of the day. the bar-keeper gave the stranger a look-over and said to him:-- "i guess we're too high for you." "well how much do you charge?" "six dollars." "yes, that's more than i can afford." he walked on until he descried on the north river, near washington market, a boarding-house so very mean and squalid that he was tempted to go in and inquire the price of board there. the price was two dollars and a half a week. "ah!" said horace, "that sounds more like it." in ten minutes more he was taking his breakfast at the landlord's table. mr. greeley gratefully remembered this landlord, who was a friendly irishman by the name of mcgorlick. breakfast done, the new-comer sallied forth in quest of work, and began by expending nearly half of his capital in improving his wardrobe. it was a wise action. he that goes courting should dress in his best, particularly if he courts so capricious a jade as fortune. then he began the weary round of the printing-offices, seeking for work and finding none, all day long. he would enter an office and ask in his whining note:-- "do you want a hand?" "no," was the invariable reply; upon receiving which he left without a word. mr. greeley chuckled as he told the reception given him at the office of the "journal of commerce," a newspaper he was destined to contend with for many a year in the columns of the "tribune." "do you want a hand?" he said to david hale, one of the owners of the paper. mr. hale looked at him from head to foot, and then said:-- "my opinion is, young man, that you're a runaway apprentice, and you'd better go home to your master." the applicant tried to explain, but the busy proprietor merely replied:-- "be off about your business, and don't bother us." the young man laughed good-humoredly and resumed his walk. he went to bed saturday night thoroughly tired and a little discouraged. on sunday he walked three miles to attend a church, and remembered to the end of his days the delight he had, for the first time in his life, in hearing a sermon that he entirely agreed with. in the mean time he had gained the good will of his landlord and the boarders, and to that circumstance he owed his first chance in the city. his landlord mentioned his fruitless search for work to an acquaintance who happened to call that sunday afternoon. that acquaintance, who was a shoemaker, had accidentally heard that printers were wanted at no. chatham street. at half-past five on monday morning horace greeley stood before the designated house, and discovered the sign, "west's printing-office," over the second story; the ground floor being occupied as a bookstore. not a soul was stirring up stairs or down. the doors were locked, and horace sat down on the steps to wait. thousands of workmen passed by; but it was nearly seven before the first of mr. west's printers arrived, and he, too, finding the door locked, sat down by the side of the stranger, and entered into conversation with him. "i saw," said this printer to me many years after, "that he was an honest, good young man, and, being a vermonter myself, i determined to help him if i could." thus, a second time in new york already, _the native quality of the man_ gained him, at the critical moment the advantage that decided his destiny. his new friend did help him, and it was very much through his urgent recommendation that the foreman of the printing-office gave him a chance. the foreman did not in the least believe that the green-looking young fellow before him could set in type one page of the polyglot testament for which help was needed. "fix up a case for him," said he, "and we'll see if he _can_ do anything." horace worked all day with silent intensity, and when he showed to the foreman at night a printer's proof of his day's work, it was found to be the best day's work that had yet been done on that most difficult job. it was greater in quantity and much more correct. the battle was won. he worked on the testament for several months, making long hours and earning only moderate wages, saving all his surplus money, and sending the greater part of it to his father, who was still in debt for his farm and not sure of being able to keep it. ten years passed. horace greeley from journeyman printer made his way slowly to partnership in a small printing-office. he founded the "new yorker," a weekly paper, the best periodical of its class in the united states. it brought him great credit and no profit. in , when general harrison was nominated for the presidency against martin van buren, his feelings as a politician were deeply stirred, and he started a little campaign paper called "the log-cabin," which was incomparably the most spirited thing of the kind ever published in the united states. it had a circulation of unprecedented extent, beginning with forty-eight thousand, and rising week after week until it reached ninety thousand. the price, however, was so low that its great sale proved rather an embarrassment than a benefit to the proprietors, and when the campaign ended, the firm of horace greeley & co. was rather more in debt than it was when the first number of "the log-cabin" was published. the little paper had given the editor two things which go far towards making a success in business,--great reputation and some confidence in himself. the first penny paper had been started. the new york "herald" was making a great stir. the "sun" was already a profitable sheet. and now the idea occurred to horace greeley to start a daily paper which should have the merits of cheapness and abundant news, without some of the qualities possessed by the others. he wished to found a cheap daily paper that should be good and salutary, as well as interesting. the last number of "the log-cabin" announced the forthcoming "tribune," price one cent. the editor was probably not solvent when he conceived the scheme, and he borrowed a thousand dollars of his old friend, james coggeshall, with which to buy the indispensable material. he began with six hundred subscribers, printed five thousand of the first number, and found it difficult to give them all away. the "tribune" appeared on the day set apart in new york for the funeral procession in commemoration of president harrison, who died a month after his inauguration. it was a chilly, dismal day in april, and all the town was absorbed in the imposing pageant. the receipts during the first week were ninety-two dollars; the expenses five hundred and twenty-five. but the little paper soon caught public attention, and the circulation increased for three weeks at the rate of about three hundred a day. it began its fourth week with six thousand; its seventh week, with eleven thousand. the first number contained four columns of advertisements; the twelfth, nine columns; the hundredth, thirteen columns. in a word, the success of the paper was immediate and very great. it grew a little faster than the machinery for producing it could be provided. its success was due chiefly to the fact that the original idea of the editor was actually carried out. he aimed to produce a paper which should morally benefit the public. it was not always right, but it always meant to be. james gordon bennett, and how he founded his herald. a cellar in nassau street was the first office of the "herald." it was a real cellar, not a basement, lighted only from the street, and consequently very dark except near its stone steps. the first furniture of this office,--as i was told by the late mr. gowans, who kept a bookstore near by,--consisted of the following articles:-- item, one wooden chair. item, two empty flour barrels with a wide, dirty pine board laid upon them, to serve as desk and table. end of the inventory. the two barrels stood about four feet apart, and one end of the board was pretty close to the steps, so that passers-by could see the pile of "heralds" which were placed upon it every morning for sale. scissors, pens, inkstand, and pencil were at the other end, leaving space in the middle for an editorial desk. this was in the summer of , when general jackson was president of the united states, and martin van buren the favorite candidate for the succession. if the reader had been in new york then, and had wished to buy a copy of the saucy little paper, which every morning amused and offended the decorous people of that day, he would have gone down into this underground office, and there he would have found its single chair occupied by a tall and vigorous-looking man about forty years of age, with a slight defect in one of his eyes, dressed in a clean, but inexpensive suit of summer clothes. this was james gordon bennett, proprietor, editor, reporter, book-keeper, clerk, office-boy, and everything else there was appertaining to the control and management of the new york "herald," price one cent. the reader would perhaps have said to him, "i want to-day's 'herald.'" bennett would have looked up from his writing, and pointed, without speaking, to the pile of papers at the end of the board. the visitor would have taken one and added a cent to the pile of copper coin adjacent. if he had lingered a few minutes, the busy writer would not have regarded him, and he could have watched the subsequent proceedings without disturbing him. in a few moments a woman might have come down the steps into the subterranean office, who answered the editor's inquiring look by telling him that she wanted a place as cook, and wished him to write an advertisement for her. this would have been entirely a matter of course, for in the prospectus of the paper it was expressly stated that persons could have their advertisements written for them at the office. the editor himself would have written the advertisement for her with the velocity of a practiced hand, then read it over to her, taking particular pains to get the name spelled right, and the address correctly stated. "how much is it, sir?" "twenty-five cents." the money paid, the editor would instantly have resumed his writing. such visitors, however, were not numerous, for the early numbers of the paper show very few advertisements, and the paper itself was little larger than a sheet of foolscap. small as it was, it was with difficulty kept alive from week to week, and it was never too certain as the week drew to a close whether the proprietor would be able to pay the printer's bill on saturday night, and thus secure its reappearance on monday morning. there were times when, after paying all the unpostponable claims, he had twenty-five cents left, or less, as the net result of his week's toil. he worked sixteen, seventeen, eighteen hours a day, struggling unaided to force his little paper upon an indifferent if not a hostile public. james gordon bennett, you will observe, was forty years old at this stage of his career. generally a man who is going to found anything extraordinary has laid a deep foundation, and got his structure a good way above ground before he is forty years of age. but there was he, past forty, and still wrestling with fate, happy if he could get three dollars a week over for his board. yet he was a strong man, gifted with a keen intelligence, strictly temperate in his habits, and honest in his dealings. the only point against him was, that he had no power and apparently no desire to make personal friends. he was one of those who cannot easily ally themselves with other men, but must fight their fight alone, victors or vanquished. a native of scotland, he was born a roman catholic, and was partly educated for the priesthood in a catholic seminary there; but he was diverted from the priestly office, as it appears, by reading byron, scott, and other literature of the day. at twenty he was a romantic, impulsive, and innocent young man, devouring the waverley novels, and in his vacations visiting with rapture the scenes described in them. the book, however, which decided the destiny of this student was of a very different description, being no other than the "autobiography of benjamin franklin," a book which was then read by almost every boy who read at all. one day, at aberdeen, a young acquaintance met him in the street, and said to him:-- "i am going to america, bennett." "to america! when? where?" "i am going to halifax on the th of april." "my dear fellow," said bennett, "i'll go with you. i want to see the place where franklin was born." three months after he stepped ashore at the beautiful town of halifax in nova scotia, with only money enough in his pocket to pay his board for about two weeks. gaunt poverty was upon him soon, and he was glad to earn a meagre subsistence for a few weeks, by teaching. he used to speak of his short residence in halifax as a time of severe privation and anxiety, for it was a place then of no great wealth, and had little to offer to a penniless adventurer, such as he was. he made his way to portland, in maine, before the first winter set in, and thence found passage in a schooner bound to boston. in one of the early numbers of his paper he described his arrival at that far-famed harbor, and his emotions on catching his first view of the city. the paragraph is not one which we should expect from the editor of the "herald," but i have no doubt it expressed his real feelings in . "i was alone, young, enthusiastic, uninitiated. in my more youthful days i had devoured the enchanting life of benjamin franklin written by himself, and boston appeared to me as the residence of a friend, an associate, an acquaintance. i had also drunk in the history of the holy struggle for independence, first made on bunker hill. dorchester heights were to my youthful imagination almost as holy ground as arthur's seat or salisbury craigs. beyond was boston, her glittering spires rising into the blue vault of heaven like beacons to light a world to liberty." in the glow of his first enthusiasm, and having nothing else to do, he spent several days in visiting the scenes of historic events with which his reading had made him familiar. but his slender purse grew daily more attenuated, and he soon found himself in a truly desperate situation, a friendless, unprepossessing young man, knowing no trade or profession, and without an acquaintance in the city. his last penny was spent. a whole day passed without his tasting food. a second day went by, and still he fasted. he could find no employment, and was too proud to beg. in this terrible strait he was walking upon boston common, wondering how it could be that he, so willing to work, and with such a capacity for work, should be obliged to pace the streets of a wealthy city, idle and starving! "how shall i get something to eat?" he said to himself. at that moment he saw something glittering upon the ground before him, which proved to be a silver coin of the value of twelve and a half cents. cheered by this strange coincidence, and refreshed by food, he went with renewed spirit in search of work. he found it almost immediately. a countryman of his own, of the firm of wells & lilly, publishers and booksellers, gave him a situation as clerk and proof-reader, and thus put him upon the track which led him to his future success. this firm lasted only long enough to give him the means of getting to new york, where he arrived in , almost as poor as when he left scotland. he tried many occupations,--a school, lectures upon political economy, instruction in the spanish language; but drifted at length into the daily press as drudge-of-all-work, at wages varying from five to eight dollars a week, with occasional chances to increase his revenue a little by the odd jobbery of literature. journalism was then an unknown art in the united states, and no newspaper had anything at all resembling an editorial corps. the most important daily newspapers of new york were carried on by the editor, aided by one or two ill-paid assistants, with a possible correspondent in washington during the session of congress. and that proved to be james gordon bennett's opportunity of getting his head a little above water. he filled the place one winter of washington corespondent to the new york "enquirer;" and while doing so he fell in by chance in the congressional library with a volume of horace walpole's gossiping society letters. he was greatly taken with them, and he said to himself: "why not try a few letters on a similar plan from washington, to be published in new york?" he tried the experiment. the letters, which were full of personal anecdotes, and gave descriptions of noted individuals, proved very attractive, and gave him a most valuable hint as to what readers take an interest in. the letters being anonymous, he remained poor and unknown. he made several attempts to get into business for himself. he courted and served the politicians. he conducted party newspapers for them, without political convictions of his own. but when he had done the work of carrying elections and creating popularity, he did not find the idols he had set up at all disposed to reward the obscure scribe to whom they owed their elevation. but all this while he was learning his trade, and though he lived under demoralizing influences, he never lapsed into bad habits. what he said of himself one day was strictly true, and it was one of the most material causes of his final victory:-- "social glasses of wine are my aversion; public dinners are my abomination; all species of gormandizing, my utter scorn and contempt. when i am hungry, i eat; when thirsty, drink. wine and viands, taken for society, or to stimulate conversation, tend only to dissipation, indolence, poverty, contempt, and death." at length, early in , having accumulated two or three hundred dollars, he conceived the notion of starting a penny paper. first he looked about for a partner. he proposed the scheme to a struggling, ambitious young printer and journalist, beginning to be known in nassau street, named horace greeley. i have heard mr. greeley relate the interview. "bennett came to me," he said, "as i was standing at the case setting type, and putting his hand in his pocket pulled out a handful of money. there was some gold among it, more silver, and i think one fifty-dollar bill. he said he had between two and three hundred dollars, and wanted me to go in with him and set up a daily paper, the printing to be done in our office, and he to be the editor. "i told him he hadn't money enough. he went away, and soon after got other printers to do the work and the 'herald' appeared." this was about six years before the "tribune" was started. mr. greeley was right in saying that his future rival in journalism had not money enough. the little "herald" was lively, smart, audacious, and funny; it pleased a great many people and made a considerable stir; but the price was too low, and the range of journalism then was very narrow. it is highly probable that the editor would have been baffled after all, but for one of those lucky accidents which sometimes happen to men who are bound to succeed. there was a young man then in the city named brandreth, who had brought a pill over with him from england, and was looking about in new york for some cheap, effective way of advertising his pill. he visited bennett in his cellar and made an arrangement to pay him a certain sum every week for a certain space in the columns of the "herald." it was the very thing he wanted, a little _certainty_ to help him over that awful day of judgment which comes every week to struggling enterprises,--saturday night! still, the true cause of the final success of the paper was the indomitable character of its founder, his audacity, his persistence, his power of continuous labor, and the inexhaustible vivacity of his mind. after a year of vicissitude and doubt, he doubled the price of his paper, and from that time his prosperity was uninterrupted. he turned everything to account. six times he was assaulted by persons whom he had satirized in his newspaper, and every time he made it tell upon his circulation. on one occasion, for example, after relating how his head had been cut open by one of his former employers, he added:-- "the fellow no doubt wanted to let out the never failing supply of good-humor and wit which has created such a reputation for the 'herald.'... he has not injured the skull. my ideas in a few days will flow as freshly as ever, and he will find it so to his cost." in this humble, audacious manner was founded the newspaper which, in the course of forty-eight years, has grown to be one of national and international importance. its founder died in , aged seventy-seven years, in the enjoyment of the largest revenue which had ever resulted from journalism in the united states, and leaving to his only son the most valuable newspaper property, perhaps, in the world. that son, the present proprietor, has greatly improved the "herald." he possesses his father's remarkable journalistic tact, with less objectionable views of the relation of the daily paper to the public. his great enterprises have been bold, far-reaching, almost national in their character. mr. frederick hudson, who was for many years the managing editor of the paper, has the following interesting paragraph concerning father and son:-- "somewhere about the year , james gordon bennett, sr., inducted james gordon bennett, jr., into the mysteries of journalism. one of his first _coups_ was the prusso-austrian war. the cable transmitted the whole of the king of prussia's important speech after the battle of sadowa and peace with austria, costing in tolls seven thousand dollars in gold." he has followed this bold _coup_ with many similar ones, and not a few that surpassed it. seven thousand dollars seems a good deal of money to pay for a single feature of one number of a daily paper. it was not so much for a paper, single issues of which have yielded half as much as that in clear profit. and the paper was born in a cellar! three john walters, and their newspaper. the reader, perhaps, does not know why the london "times" is the first journal of europe. i will tell him. the starting of this great newspaper ninety-nine years ago was a mere incident in the development of another business. almost every one who has stood in a printing-office watching compositors set type must have sometimes asked himself, why not have whole words cast together, instead of obliging the printer to pick up each letter separately? such words as _and_, _the_, _but_, _if_, _is_, and even larger words, like _although_ and _notwithstanding_, occur very often in all compositions. how easy it would be, inexperienced persons think, to take up a long word, such as _extraordinary_, and place it in position at one stroke. i confess that i had this idea myself, long before i knew that any one else had ever had it. in the year there was a printer in london named john walter, well-established in business, who was fully resolved on giving this system a trial. at great expense and trouble he had all the commonest words and phrases cast together. he would give his type-founder an order like this:-- send me a hundredweight, made up in separate pounds, of _heat_, _cold_, _wet_, _dry_, _murder_, _fire_, _dreadful_ _robbery_, _atrocious outrage_, _fearful calamity_, and _alarming explosion_. this system he called logographic printing,--logographic being a combination of two greek words signifying word-writing. in order to give publicity to the new system, on which he held a patent, as well as to afford it a fuller trial, he started a newspaper, which he called the "daily universal register." the newspaper had some little success from the beginning; but the logographic printing system would not work. not only did the compositors place obstacles in the way, but the system itself presented difficulties which neither john walter nor any subsequent experimenter has been able to surmount. "the whole english language," said walter, in one of his numerous addresses to the public, "lay before me in a confused arrangement. it consisted of about ninety thousand words. this multitudinous mass i reduced to about five thousand, by separating the parcels, and removing the obsolete words, technical terms, and common terminations." after years of labor this most resolute and tenacious of men was obliged to give it up. it was too expensive, too cumbersome, too difficult; it required a vast amount of space; and, in short, it was a system which could not, and cannot, be worked to profit. but though the logographic printing was a failure, the "daily universal register" proved more and more successful. it was a dingy little sheet, about twice as large as a sheet of foolscap, without a word of editorial, and containing a small number of well-selected paragraphs of news. it had also occasionally a short notice of the plays of the night before, and a few items of what we now call society gossip. the advertisements, after the paper had been in existence three years, averaged about fifty a day, most of them very short. its price was threepence, english, equal to about twelve cents of our present currency. the paper upon which it was printed was coarse and cheap. in the third year of its existence, on the first of january, , the name was changed to "the times." the editor humorously explained the reasons for changing the name:-- "'boy, bring me the "register."' the waiter answers, 'sir, we have no library, but you may see it in the new exchange coffee house.' 'then i will see it there,' answers the disappointed politician, and he goes to the new exchange coffee house, and calls for the 'register'; upon which the waiter tells him he cannot have it, as he is not a subscriber; or presents him with the 'court and city register,' the 'old annual register,' or the 'new annual register.'" john walter was not what is commonly called an educated man. he was a brave and honest englishman, instinctively opposed to jobbery, and to all the other modes by which a corrupt government plunders a laborious people. the consequence was that during the first years of his editorial life he was frequently in very hot water. when "the times" had been in existence little more than a year, he took the liberty of making a remark upon the duke of york, one of the king's dissolute sons, saying that the conduct of his royal highness had been such as to incur his majesty's just disapprobation. for this offense he was arrested and put on trial for libel. being convicted, he was sentenced to pay a fine of fifty pounds, to undergo a year's imprisonment in newgate, to stand in the pillory for one hour, and give bonds for his good behavior for the next seven years. while he was still in prison, he was convicted of two libels: first for saying that both the prince of wales and the duke of york had incurred the just disapprobation of the king; and secondly, for saying that the duke of clarence, another son of george iii., an officer in the navy, had left his station without the permission of his commanding officer. for these offenses he was condemned to pay fines amounting to two hundred pounds, and to suffer a second year's imprisonment. his first year he served out fully, and four months of the second, when by the intercession of the prince of wales he was released. from this period the newspaper appears to have gone forward, without any interruption, to the present day. in due time john walter withdrew from the management, and gave it up to his eldest son, john walter the second, who seems to have possessed his father's resolution and energy, with more knowledge of the world and a better education. it was he who took the first decisive step toward placing "the times" at the head of journalism. for many years the walters had been printers to the custom house, a post of considerable profit. in the newspaper discovered and exposed corrupt practices in the navy department,--practices which were subsequently condemned by an investigating commission. the administration deprived the fearless editor of the custom house business. as this was not in accordance with the usages of english politics, it made a great outcry, and the editor was given to understand that, if he would wink at similar abuses in future, the public printing should be restored to him. this offer he declined, saying that he would enter into no engagements and accept no favors which would diminish, in any degree whatever, the independence of the paper. this was an immense point gained. it was, as i have said, the first step toward greatness. nor do i believe that any newspaper has ever attained a genuine and permanent standing in a community until it has first conquered a substantial independence. the administration then tried to accomplish its purpose in another way. during the gigantic wars of napoleon bonaparte, extending over most of the first fifteen years of the present century, "the times" surpassed all newspapers in procuring early intelligence from the seat of war. the government stooped to the pettiness of stopping at the outposts all packages addressed to "the times," while allowing dispatches for the ministerial journals to pass. foreign ships bound to london were boarded at gravesend, and papers addressed to "the times" were taken from the captain. the editor remonstrated to the home secretary. he was informed that he might receive his foreign papers _as a favor_ from government. knowing that this would be granted in the expectation of its modifying the spirit and tone of the newspaper, he declined to accept as a favor that which he claimed as a right. the consequence was that the paper suffered much inconvenience from the loss or delay of imported packages. but this inconvenience was of small account compared with the prestige which such complimentary persecution conferred. another remarkable feature of the system upon which "the times" has been conducted is the liberality with which it has compensated those who served it. writing is a peculiar kind of industry, and demands so strenuous and intense an exertion of the vital forces, that no one will ever get good writing done who compensates it on ordinary commercial principles. the rule of supply and demand can never apply to this case. there are two things which the purchaser of literary labor can do towards getting a high quality of writing. one is, to give the writer the amplest motive to do his best; and the other is, to prevent his writing too much. both these things the conductors of "the times" have systematically done. it is their rule to pay more for literary labor than any one else pays for the same labor, more than the writer himself would think of demanding, and also to afford intervals of repose after periods of severe exertion. until the year , all the printing in the world was done by hand, and "the times" could only be struck off at the rate of four hundred and fifty copies an hour. hence the circulation of the paper, when it had reached three or four thousand copies a day, had attained the utmost development then supposed to be possible; and when such news came as that of the battle of austerlitz, trafalgar, or waterloo, the edition was exhausted long before the demand was supplied. there was a compositor in the office of "the times," named thomas martyn, who, as early as , conceived the idea of applying watt's improved steam-engine to a printing press. he showed his model to john walter, who furnished him with money and room in which to continue his experiments, and perfect his machine. but the pressmen pursued the inventor with such blind, infuriate hate, that the man was in terror of his life from day to day, and the scheme was given up. ten years later another ingenious inventor, named könig, procured a patent for a steam-press, and mr. walter determined to give his invention a trial at all hazards. the press was secretly set up in another building, and a few men, pledged to secrecy, were hired and put in training to work it. on the night of the trial the pressmen in "the times" building were told that the paper would not go to press until very late, as important news was expected from the continent. at six in the morning john walter went into the press-room, and announced to the men that the whole edition of "the times" had been printed by steam during the night, and that thenceforward the steam-press would be regularly used. he told the men that if they attempted violence there was a force at hand to suppress it, but if they behaved well no man should be a loser by the invention. they should either remain in their situations, or receive full wages until they could procure others. this conduct in a rich and powerful man was no more than decent. the men accepted his terms with alacrity. a great secret of "the times'" popularity has been its occasional advocacy of the public interest to its own temporary loss. early in its history it ridiculed the advertisers of quack medicines, and has never hesitated to expose unsound projects though ever so profusely advertised. during the railroad mania of , when the railroad advertisements in "the times" averaged sixty thousand dollars a week, it earnestly, eloquently, and every day, week after week, exposed the empty and ruinous nature of the railway schemes. it continued this course until the mighty collapse came which fulfilled its own prophecies, and paralyzed for a time the business of the country. was this pure philanthropy? it was something much rarer than that--it was good sense. it was sound judgment. it was _not_ killing the goose that laid the golden egg. old readers of the london "times" were a little surprised, perhaps, to see the honors paid by that journal to its late editor-in-chief. an obituary notice of several columns was surrounded by black lines; a mark of respect which the paper would pay only to members of the royal family, or to some public man of universal renown. never before, i believe, did this newspaper avow to the world that its editor had a name; and the editor himself usually affected to conceal his professional character. former editors, in fact, would flatly deny their connection with the paper, and made a great secret of a fact which was no secret at all. mr. carlyle, in his "life of sterling," gives a curious illustration of this. sir robert peel, in , upon resigning his ministry, wrote a letter to the editor of "the times," thanking him for the powerful support which his administration had received from that journal. sir robert peel did not presume to address this letter to any individual by name, and he declared in this letter that the editor was unknown to him even by sight. edward sterling replied in a lofty tone, very much as one king might reply to another, and signed the letter simply "the editor of 'the times.'" but all this is changed. the affectation of secrecy, long felt to be ridiculous, has been abandoned, and the editor now circulates freely among his countrymen in his true character, as the conductor of the first journal in europe. at his death he receives the honors due to the office he holds and the power he exerts, and his funeral is publicly attended by his associates. this is as it should be. journalism has now taken its place as one of the most important of the liberal professions. next to statesmanship, next to the actual conduct of public affairs, the editor of a leading newspaper fills, perhaps, the most important place in the practical daily life of the community in which he lives; and the influence of the office is likely to increase, rather than diminish. mr. delane was probably the first individual who was ever educated with a distinct view to his becoming an editor. while he was still a boy, his father, a solicitor by profession, received an appointment in the office of "the times," which led to young delane's acquaintance with the proprietors of the journal. it seems they took a fancy to the lad. they perceived that he had the editorial cast of character, since, in addition to uncommon industry and intelligence, he had a certain eagerness for information, an aptitude for acquiring it, and a discrimination in weighing it, which marks the journalistic mind. the proprietors, noting these traits, encouraged, and, i believe, assisted him to a university education, in the expectation that he would fit himself for the life editorial. having begun this course of preparation early, he entered the office of "the times" as editorial assistant soon after he came of age, and acquitted himself so well that, in , when he was not yet twenty-five, he became editor-in-chief. he was probably the youngest man who ever filled such a post in a daily paper of anything like equal importance. this rapid promotion will be thought the more remarkable when it is mentioned that he never wrote an editorial in his life. "the times" itself says of him:-- "he never was a writer. he never even attempted to write anything, except reports and letters. these he had to do, and he did them well. he had a large staff of writers, and it was not necessary he should write, except to communicate with them." his not being a writer was one of his strongest points. writing is a career by itself. the composition of one editorial of the first class is a very hard day's work, and one that leaves to the writer but a small residue of vital force. writing for the public is the most arduous and exhausting of all industries, and cannot properly be combined with any other. nor can a man average more than two or three editorial articles a week such as "the times" prints every day. it was an immense advantage to the paper to have an editor who was never tempted to waste any of his strength upon the toil of composition. "the times" prints daily three editorial articles, which cost the paper on an average fifty dollars each. mr. delane himself mentioned this during his visit to this country. there was one quality of his editorship which we ought not to overlook. it was totally free from personalities. i have been in the habit for a long time of reading "the times"--not regularly but very frequently, and sometimes every day for a considerable period; but i have never seen an individual disrespectfully mentioned in the paper. an opinion may be denounced; but the individual holding that opinion is invariably spoken of with decency. "the times" has frequently objected to the course pursued by mr. gladstone; but the man himself is treated with precisely the same respect as he would be if he were an invited guest at the editor's table. "the times," being a human institution, has plenty of faults, and has made its ample share of mistakes; but it owes its eminent position chiefly to its good qualities, its business ability, its patriotism, its liberal enterprise, and wise treatment of those who serve it. the paper is still chiefly owned and conducted by john walter, the grandson of the founder. george hope. the story of this stalwart and skillful scotch farmer, george hope, enables us to understand what agitators mean by the term "landlordism." it is a very striking case, as the reader will admit. george hope, born in , was the son of a tenant farmer of the county of east lothian, now represented in parliament by mr. gladstone. the farm on which he was born, on which his ancestors had lived, and upon which he spent the greater part of his own life, was called fenton barns. with other lands adjacent, it made a farm of about eight hundred acres. two thirds of it were of a stiff, retentive clay, extremely hard to work, and the rest was little better than sand, of a yellow color and incapable of producing grain. two or three generations of hopes had spent life and toil unspeakable upon this unproductive tract, without making the least profit by it; being just able to pay their rent, and keep their heads above water. they subsisted, reared families, and died, worn out with hard work, leaving to their sons, besides an honest name, only the same inheritance of struggle and despair. george hope's mother tried for years to squeeze out of her butter and eggs the price of a table large enough for all her family to sit round at once, but died without obtaining it. at the age of eighteen years, george hope took hold of this unpromising farm, his parents being in declining health, nearly exhausted by their long struggle with it. he brought to his task an intelligent and cultivated mind. he had been for four years in a lawyer's office. he had read with great admiration the writings of the american channing; and he now used his intelligence in putting new life into this old land. the first thing was to acquire more capital; and the only way of accomplishing this was to do much of the work himself. mere manual labor, however, would not have sufficed; for he found himself baffled by the soil. part of the land being wet, cold clay, and part yellow sand, he improved both by mixing them together. he spread sand upon his clay, and clay upon his sand, as well as abundant manure, and he established a kiln for converting some of the clay into tiles, with which he drained his own farm, besides selling large quantities of tiles to the neighboring farmers. for a time, he was in the habit of burning a kiln of eleven thousand tiles every week, and he was thus enabled to expend in draining his own farms about thirteen thousand dollars, without going in debt for it. he believed in what is called "high farming," and spent enormous sums in fertilizing the soil. for a mere top-dressing of guano, bones, nitrate of soda, or sulphate of ammonia, he spent one spring eight thousand dollars. these large expenditures, directed as they were by a man who thoroughly understood his business, produced wonderful results. he gained a large fortune, and his farm became so celebrated, that travelers arrived from all parts of europe, and even from the united states, to see it. an american called one day to inspect the farm, when mr. hope began, as usual, to express his warm admiration for dr. channing. the visitor was a nephew of the distinguished preacher, and he was exceedingly surprised to find his uncle so keenly appreciated in that remote spot. it is difficult to say which of his two kinds of land improved the most under his vigorous treatment. his sandy soil, the crop of which in former years was sometimes blown out of the ground, was so strengthened by its dressing of clay as to produce excellent crops of wheat; and his clay fields were made among the most productive in scotland by his system of combined sanding, draining and fertilizing. one of his secrets was that he treated his laborers with justice and consideration. his harvest-homes were famous in their day. when he found that certain old-fashioned games caused some of his weak teetotalers to fall from grace, he changed them for others; and, instead of beer and toddy, provided abundance of tea, coffee, strawberries, and other dainties. when the time came for dancing, he took the lead, and could sometimes boast that he had not missed one dance the whole evening. in addressing a public meeting of farmers and landlords in , he spoke on the subject of improving the cottages of farm laborers. these were some of the sentences which fell from his lips:-- "treat your laborers with respect, as men; encourage their self-respect. never enter a poor man's house any more than a rich man's unless invited, and then go not to find fault, but as a friend. if you can render him or his family a service, by advice or otherwise, let it be more delicately done than to your most intimate associate. remember how hard it is for a poor man to respect himself. he hears the wealthy styled the respectable, and the poor, the lower classes; but never call a man low. his being a _man_ dwarfs, and renders as nothing, all the distinctions of an earthly estate." the reader sees what kind of person this george hope was. he was as nearly a perfect character as our very imperfect race can ordinarily exhibit. he was a great farmer, a true captain of industry, an honest, intelligent, just, and benevolent man. he was, moreover, a good citizen, and this led him to take an interest in public matters, and to do his utmost in aid of several reasonable reforms. he was what is called a liberal in politics. he did what he could to promote the reform bill of lord john russell, and he was a conspicuous ally of cobden and bright in their efforts to break down the old corn laws. he remembered that there were about five thousand convictions in great britain every year under the game laws, and he strove in all moderate and proper ways to have those laws repealed. and now we come to the point. a certain person named r. a. dundas christopher nisbet hamilton married the heiress of the estate to which the farm of george hope belonged. he thus acquired the power, when a tenant's lease expired, to refuse a renewal. this person was a tory, who delighted in the slaughter of birds and beasts, and who thought it highly impertinent in the tenant of a farm to express political opinions contrary to those of his landlord. george hope, toward the end of his long lease, offered to take the farm again, at a higher rent than he had ever before paid, though it was himself who had made the farm more valuable. his offer was coldly declined, and he was obliged, after expending the labor and skill of fifty-three years upon that land, to leave it, and find another home for his old age. he had fortunately made money enough to buy a very good farm for himself, and he had often said that he would rather farm fifty acres of his own than to be the tenant of the best farm in europe. this "eviction," as it was called, of a farmer so celebrated attracted universal comment, and excited general indignation. he left his farm like a conqueror. public dinners and services of plate were presented to him, and his landlord of many names acquired a notoriety throughout europe which no doubt he enjoyed. he certainly did a very bold action, and one which casts a perfect glare of light upon the nature of landlordism. george hope died in , universally honored in scotland. he lies buried in the parish of his old farm, not far from the home of his fathers. on his tombstone is inscribed:-- "to the memory of george hope, for many years tenant of fenton barns. he was the devoted supporter of every movement which tended to the advancement of civil and religious liberty, and to the moral and social elevation of mankind." sir henry cole. he was an "old public functionary" in the service of the british people. when president buchanan spoke of himself as an old public functionary he was a good deal laughed at by some of the newspapers, and the phrase has since been frequently used in an opprobrious or satirical sense. this is to be regretted, for there is no character more respectable, and there are few so useful, as an intelligent and patriotic man of long standing in the public service. what _one_ such man can do is shown by the example of sir henry cole, who died a few months ago in london after half a century of public life. the son of an officer in the british army, he was educated at that famous blue-coat school which is interesting to americans because lamb and coleridge attended it. at the age of fifteen he received an appointment as clerk in the office of public records. in due time, having proved his capacity and peculiar fitness, he was promoted to the post of assistant keeper, which gave him a respectable position and some leisure. he proved to be in an eminent sense the right man in the right place. besides publishing, from time to time, curious and interesting documents which he discovered in his office, he called attention, by a series of vigorous pamphlets, to the chaotic condition in which the public records of great britain were kept. gradually these pamphlets made an impression, and they led at length to a reform in the office. the records were rearranged, catalogued, rendered safe, and made accessible to students. this has already led to important corrections in history, and to a great increase in the sum of historical knowledge. when the subject of cheap postage came up in , the government offered four prizes of a hundred pounds each for suggestions in aid of sir rowland hill's plan. one of these prizes was assigned to henry cole. he was one of the persons who first became converts to the idea of penny postage, and he lent the aid of his pen and influence to its adoption. at length, about the year , he entered upon the course of proceedings which rendered him one of the most influential and useful persons of his time. he had long lamented the backward condition of arts of design in england, and the consequent ugliness of the various objects in the sight and use of which human beings pass their lives. english furniture, wall-papers, carpets, curtains, cutlery, garments, upholstery, ranged from the tolerable to the hideous, and were inferior to the manufactures of france and germany. he organized a series of exhibitions on a small scale, somewhat similar to those of the american institute in new york, which has held a competitive exhibition of natural and manufactured objects every autumn for the last fifty years. his exhibitions attracted attention, and they led at length to the crystal palace exhibition of . the merit of that scheme must be shared between henry cole and prince albert. cole suggested that his small exhibitions should, once in five years, assume a national character, and invite contributions from all parts of the empire. yes, said prince albert, and let us also invite competition from foreign countries on equal terms with native products. the exhibition of was admirably managed, and had every kind of success. it benefited england more than all other nations put together, because it revealed to her people their inferiority in many branches both of workmanship and design. we all know how conceited people are apt to become who have no opportunity to compare themselves with superiors. john bull, never over-modest, surveyed the exhibition of , and discovered, to his great surprise, that he was not the unapproachable bull of the universe which he had fondly supposed. he saw himself beaten in some things by the french, in some by the germans, in others by the italians, and in a few (o wonder!) by the yankees. happily he had the candor to admit this humiliating fact to himself, and he put forth earnest and steadfast exertions to bring himself up to the level of modern times. henry cole was the life and soul of the movement. it was he who called attention to the obstacles placed in the way of improvement by the patent laws, and some of those obstacles, through him, were speedily removed. during this series of services to his country, he remained in the office of public records. the government now invited him to another sphere of labor. they asked him to undertake the reconstruction of the schools of design, and they gave him an office which placed him practically at the head of the various institutions designed to promote the application of art to manufacture. the chief of these now is the museum of south kensington, which is to many americans the most interesting object in london. the creation of this wonderful museum was due more to him than to any other individual. it came to pass in this way: after the close of the crystal palace in , parliament gave five thousand pounds for the purchase of the objects exhibited which were thought best calculated to raise the standard of taste in the nation. these objects, chiefly selected by cole, were arranged by him for exhibition in temporary buildings of such extreme and repulsive inconvenience as to bring opprobrium and ridicule upon the undertaking. it was one of the most difficult things in the world to excite public interest in the exhibition. but by that energy which comes of strong conviction and patriotic feeling, and of the opportunity given him by his public employment, henry cole wrung from a reluctant parliament the annual grants necessary to make south kensington museum what it now is. magnificent buildings, filled with a vast collection of precious and interesting objects, greet the visitor. there are collections of armor, relics, porcelain, enamel, fabrics, paintings, statues, carvings in wood and ivory, machines, models, and every conceivable object of use or beauty. some of the most celebrated pictures in the world are there, and there is an art library of thirty thousand volumes. there are schools for instruction in every branch of art and science which can be supposed to enter into the products of industry. the prizes which are offered for excellence in design and invention have attracted, in some years, as many as two hundred thousand objects. during three days of every week admission to this superb assemblage of exhibitions is free, and on the other three days sixpence is charged. the influence of this institution upon british manufactures has been in many branches revolutionary. as the london "times" said some time ago:-- "there is hardly a household in the country that is not the better for the change; there is certainly no manufacture in which design has any place which has not felt its influence." the formation of this museum, the chief work of sir henry cole's useful life, was far from exhausting his energies. he has borne a leading part in all the industrial exhibitions held in london during the last quarter of a century, and served as english commissioner at the paris exhibitions of and . this man was enabled to render all this service to his country, to europe, and to us, because he was not obliged to waste any of his energies in efforts to keep his place. administrations might change, and parliaments might dissolve; but he was a fixture as long as he did his duty. when his duty was fairly done, and he had completed the fortieth year of his public service, he retired on his full salary, and he was granted an honorable title; for a title _is_ honorable when it is won by good service. henceforth he was called sir henry cole, k. c. b. to the end of his life he continued to labor in all sorts of good works--a training school for music, a training school for cookery, guilds for the promotion of health, and many others. he died in april, , aged seventy-four years. charles summers. strangers visiting melbourne, the chief city of australia, will not be allowed to overlook four great marble statues which adorn the public library. they are the gift of mr. w. j. clark, one of the distinguished public men of that growing empire. these statues represent, in a sitting posture, queen victoria, prince albert, the prince of wales, and the princess of wales. they are larger than life, and, according to the australian press, they are admirable works in every respect. they were executed by charles summers, a sculptor long resident in that colony, where he practiced his art with great success, as the public buildings and private houses of melbourne attest. many of his works remain in the colony, and he may be said to be the founder of his form of art in that part of the world. the history of this man's life is so remarkable that i think it will interest the reader. sixty years ago, charles summers was a little, hungry, ragged boy in english somersetshire, who earned four cents a day by scaring the crows from the wheat fields. i have seen myself such little fellows engaged in this work, coming on duty before four in the morning, and remaining till eight in the evening, frightening away the birds by beating a tin pan with a stick, not unfrequently chasing them and throwing stones at them. he was the son of a mason, who had eight children, and squandered half his time and money in the tap-room. hence, this boy, from the age of eight or nine years, smart, intelligent, and ambitious, was constantly at work at some such employment; and often, during his father's drunken fits, he was the chief support of the family. besides serving as scare-crow, he assisted his father in his mason's work, and became a hod-carrier as soon as he was able to carry a hod. sometimes he accompanied his father to a distant place in search of employment, and he was often seen on the high-road, in charge of the drunkard, struggling to get him home before he had spent their united earnings in drink. in these deplorable circumstances, he acquired a dexterity and patience which were most extraordinary. before he was twelve years old he began to handle the chisel and the mallet, and his work in squaring and facing a stone soon surpassed that of boys much older than himself. he was observed to have a strong propensity to do fancy stone-work. he obtained, as a boy, some local celebrity for his carved gate posts, and other ornamental objects in stone. so great was his skill and industry, that, by the time he was nineteen years of age, besides having maintained a large family for years, he had saved a sum equal to a hundred dollars. then a piece of good fortune happened to him. a man came from london to set up in a parish church near by a monumental figure, and looked about for a skillful mason to assist him. charles summers was mentioned as the best hand in the neighborhood, and upon him the choice fell. thus he was introduced to the world of art, for this figure had been executed by henry weekes, a distinguished london sculptor. the hardships of his childhood had made a man of him at this early age, a thoughtful and prudent man. taking with him ten of his twenty pounds, he went to london and applied for employment in the studio of henry weekes. this artist employed several men, but he had no vacant place except the humble one of stone polisher, which required little skill. he accepted the place with alacrity and delight, at a salary of five dollars a week. he was now in his element. the lowliest employments of the studio were pleasing to him. he loved to polish the marble; the sight of the numerous models was a pleasure to him; even wetting the cloths and cleaning the model tools were pleasant tasks. his cheerfulness and industry soon made him a favorite; and when his work was done, he employed his leisure in gaining skill in carving and cutting marble. in this he had such success, that, when in after life he became himself an artist, he would sometimes execute his idea in marble without modeling it in clay. when he had been in this studio about a year, his employer was commissioned to execute two colossal figures in bronze, and the young man was obliged to spend much of his time in erecting the foundry, and other duties which he felt to be foreign to his art. impatient at this, he resigned his place, and visited his home, where he executed medallion portraits, first of his own relations, and afterwards of public men, such as the mayor of bristol, and the member of parliament for his county. these medallions gave him some reputation, and it was a favorite branch with him as long as he lived. returning to london, he had no difficulty in gaining employment at good wages in a studio of a sculptor. soon we find him competing for the prizes offered by the royal academy of london to young sculptors; the chief of which is a gold medal given every two years for the best group in clay of an historical character. a silver medal is also given every year for the best model from life. at the exhibition of , when he was twenty-four years of age, he was a competitor for both these prizes. for the gold medal he executed a group which he called mercy interceding for the vanquished. for the silver medal he offered a bust of a living person. he had the singular good fortune of winning both, and he received them in public from the hands of the president of the academy, sir charles eastlake. cheer upon cheer greeted the modest student when he rose and went forward for the purpose. he was a young man of great self-control. instead of joining in the usual festivities of his fellow-students after the award, he walked quietly to his lodgings, where his father and brother were anxiously waiting to hear the result of the competition. he threw himself into a chair without a word, and they began to console him for the supposed disappointment. in a few minutes they sat down to supper; whereupon, with a knowing smile, he took his medals out of his pocket, and laid one of them on each side of his plate. from this time he had no difficulties except those inherent in the nature of his work, and in his own constitution. his early struggle with life had made him too intense. he had scarcely known what play was, and he did not know how to recreate himself. he had little taste for reading or society. he loved art alone. the consequence was that he worked with an intensity and continuity that no human constitution could long endure. soon after winning his two medals his health was so completely prostrated that he made a voyage to australia to visit a brother who had settled there. the voyage restored him, and he soon resumed the practice of his art at melbourne. the people were just building their houses of parliament, and he was employed to execute the artistic work of the interior. he lived many years in australia, and filled the colony with his works in marble and bronze. in due time he made the tour of europe, and lingered nine years in rome, where he labored with suicidal assiduity. he did far more manual labor himself than is usual with artists of his standing, and yet, during his residence in rome he had twenty men in his service. it was in rome, in , that he received from melbourne the commission to execute in marble the four colossal statues mentioned above. these works he completed in something less than eighteen months, besides doing several other minor works previously ordered. it was too much, and nature resented the affront. after he had packed the statues, and sent them on their way to the other side of the globe, he set out for melbourne himself, intending to take england by the way for medical advice. at paris he visited the exhibition, and the next day, at his hotel, he fell senseless to the floor. in three weeks he was dead, at the age of fifty-one years, in the very midst of his career. "for him," writes one of his friends, "life consisted of but one thing--_art_. for that he lived; and, almost in the midst of it, died. he could not have conceived existence without it. always and under every circumstance, he was thinking of his work, and gathering from whatever surrounded him such information as he thought would prove of service. in omnibuses, in railway carriages, and elsewhere, he found opportunities of study, and could always reproduce a likeness from memory of the individuals so observed." i do not copy these words as commendation, but as warning. like so many other gifted men of this age, he lived too fast and attempted too much. he died when his greatest and best life would naturally have been just beginning. he died at the beginning of the period when the capacity for high enjoyment of life is naturally the greatest. he died when he could have ceased to be a manufacturer and become an artist. william b. astor. house-owner. in estimating the character and merits of such a man as the late mr. astor, we are apt to leave out of view the enormous harm he might have done if he had chosen to do it. the rich fool who tosses a dollar to a waiter for some trifling service, debases the waiter, injures himself, and wrongs the public. by acting in that manner in all the transactions of life, a rich man diffuses around him an atmosphere of corruption, and raises the scale of expense to a point which is oppressive to many, ruinous to some, and inconvenient to all. the late mr. astor, with an income from invested property of nearly two millions a year, could have made life more difficult than it was to the whole body of people in new york who are able to live in a liberal manner. he refrained from doing so. he paid for everything which he consumed the market price--no more, no less--and he made his purchases with prudence and forethought. as he lived for many years next door to the astor library, the frequenters of that noble institution had an opportunity of observing that he laid in his year's supply of coal in the month of june, when coal is cheapest. there was nothing which he so much abhorred as waste. it was both an instinct and a principle with him to avoid waste. he did not have the gas turned down low in a temporarily vacated room because he would save two cents by doing so, but because he justly regarded waste as wicked. his example in this particular, in a city so given to careless and ostentatious profusion as new york, was most useful. we needed such an example. nor did he appear to carry this principle to an extreme. he was very far from being miserly, though keenly intent upon accumulation. in the life of the old world there is nothing so shocking to a republicanized mind as the awful contrast between the abodes of the poor and the establishments of the rich. a magnificent park of a thousand acres of the richest land set apart and walled in for the exclusive use of one family, while all about it are the squalid hovels of the peasants to whom the use of a single acre to a family would be ease and comfort, is the most painful and shameful spectacle upon which the sun looks down this day. nothing can make it right. it is monstrous. it curses _equally_ the few who ride in the park and the many who look over its walls; for the great lord who can submit to be the agent of such injustice is as much its victim as the degraded laborer who drowns the sense of his misery in pot-house beer. the mere fact that the lord can look upon such a scene and not stir to mend it, is proof positive of a profound vulgarity. nor is it lords alone who thus waste the hard earned wealth of the toiling sons of men. i read some time ago of a wedding in paris. a thriving banker there, who is styled the baron alphonse de rothschild, having a daughter of seventeen to marry, appears to have set seriously to work to find out how much money a wedding could be made to cost. in pursuing this inquiry, he caused the wedding festivals of louis xiv's court, once so famous, to seem poverty-stricken and threadbare. he began by a burst of ostentatious charity. he subscribed money for the relief of the victims of recent inundations, and dowered a number of portionless girls; expending in these ways a quarter of a million francs. he gave his daughter a portion of five millions of francs. one of her painted fans cost five thousand francs. he provided such enormous quantities of clothing for her little body, that his house, if it had not been exceedingly large, would not have conveniently held them. for the conveyance of the wedding party from the house to the synagogue, he caused twenty-five magnificent carriages to be made, such as monarchs use when they are going to be crowned, and these vehicles were drawn by horses imported from england for the purpose. the bridal veil was composed of ineffable lace, made from an original design expressly for this bride. and then what doings in the synagogue! a choir of one hundred and ten trained voices, led by the best conductor in europe--the first tenor of this generation engaged, who sang the prayer from "moses in egypt"--a crowd of rabbis, and assistant-rabbis, with the grand rabbi of paris at their head. to complete the histrionic performance, eight young girls, each bearing a beautiful gold-embroidered bag, and attended by a young gentleman, "took up a collection" for the poor, which yielded seven thousand francs. mr. astor could, if he had chosen, have thrown his millions about in this style. he was one of a score or two of men in north america who could have maintained establishments in town and country on the dastardly scale so common among rich people in europe. he, too, could have had his park, his half a dozen mansions, his thirty carriages, his hundred horses and his yacht as big as a man-of-war. that he was above such atrocious vulgarity as this, was much to his credit and more to our advantage. what he could have done safely, other men would have attempted to whom the attempt would have been destruction. some discredit also would have been cast upon those who live in moderate and modest ways. every quarter day mr. astor had nearly half a million dollars to invest in the industries of the country. to invest his surplus income in the best and safest manner was the study of his life. his business was to take care of and increase his estate; and that _being_ his business, he was right in giving the necessary attention to it. "william will never make money," his father used to say; "but he will take good care of what he has." and so it proved. the consequence was, that all his life he invested money in the way that was at once best for himself and best for the country. no useless or premature scheme had had any encouragement from him. he invariably, and by a certainty of judgment that resembled an instinct, "put his money where it would do most good." political economists demonstrate that an investment which is the best for the investor must of necessity be the best for the public. here, again, we were lucky. when we wanted houses more than we wanted coal, he built houses for us; and when we wanted coal more than we wanted houses, he set his money to digging coal; charging nothing for his trouble but the mere cost of his subsistence. one fault he had as a public servant--for we may fairly regard in that light a man who wields so large a portion of our common estate. he was one of the most timid of men. he was even timorous. his timidity was constitutional and physical. he would take a great deal of trouble to avoid crossing a temporary bridge or scaffolding, though assured by an engineer that it was strong enough to bear ten elephants. nor can it be said that he was morally brave. year after year he saw a gang of thieves in the city hall stealing his revenues under the name of taxes and assessments, but he never led an assault upon them nor gave the aid he ought to those who did. unless he is grossly belied, he preferred to compromise than fight, and did not always disdain to court the ruffians who plundered him. this was a grave fault. he who had the most immediate and the most obvious interest in exposing and resisting the scoundrels, ought to have taken the lead in putting them down. this he could not do. nature had denied him the qualities required for such a contest. he had his enormous estate, and he had mind enough to take care of it in ordinary ways; but he had nothing more. we must therefore praise him less for the good he did in his life, than for the evil which he refrained from doing. [illustration: peter cooper.] peter cooper. on an april morning in i was seated at breakfast in a room which commanded a view of the tall flag-staff in gramercy park in the city of new york. i noticed some men unfolding the flag and raising it on the mast. the flag stopped mid-way and dropped motionless in the still spring morning. the newspapers which were scattered about the room made no mention of the death of any person of note and yet this sign of mourning needed no explanation. for half a lifetime peter cooper had lived in a great, square, handsome house just round the corner, and the condition of the aged philanthropist had been reported about the neighborhood from hour to hour during the previous days; so that almost every one who saw the flag uttered words similar to those which i heard at the moment:-- "he is gone, then! the good old man is gone. we shall never see his snowy locks again, nor his placid countenance, nor his old horse and gig jogging by. peter cooper is dead!" he had breathed his last about three o'clock that morning, after the newspapers had gone to press; but the tidings spread with strange rapidity. when i went out of the house two hours later, the whole city seemed hung with flags at half-mast; for there is probably no city in the world which has so much patriotic bunting at command as new york. passengers going north and west observed the same tokens of regard all along the lines of railroad. by mid-day the great state of new york, from the narrows to the lakes, and from the lakes to the pennsylvania line, exhibited everywhere the same mark of respect for the character of the departed. a tribute so sincere, so spontaneous and so universal, has seldom been paid to a private individual. it was richly deserved. peter cooper was a man quite out of the common order even of good men. his munificent gift to the public, so strikingly and widely useful, has somewhat veiled from public view his eminent executive qualities, which were only less exceptional than his moral. i once had the pleasure of hearing the story of his life related with some minuteness by a member of his own family, now honorably conspicuous in public life, and i will briefly repeat it here. more than ninety years ago, when john jacob astor kept a fur store in water street, and used to go round himself buying his furs of the hudson river boatmen and the western indians, he had a neighbor who bought beaver skins of him, and made them into hats in a little shop near by, in the same street. this hat-maker, despite his peaceful occupation, was called by his friends captain cooper, for he had been a good soldier of the revolution, and had retired, after honorable service to the very end of the war, with a captain's rank. captain cooper was a better soldier than man of business. indeed, new york was then a town of but twenty-seven thousand inhabitants, and the field for business was restricted. he was an amiable, not very energetic man; but he had had the good fortune to marry a woman who supplied all his deficiencies. the daughter of one of the colonial mayors of new york, she was born on the very spot which is now the site of st. paul's church at the corner of broadway and fulton street, and her memory ran back to the time when the stockade was still standing which had been erected in the early day as a defense against the indians. there is a vivid tradition in the surviving family of peter cooper of the admirable traits of his mother. she was educated among the moravians in pennsylvania, who have had particular success in forming and developing the female character. she was a woman in whom were blended the diverse qualities of her eminent son, energy and tenderness, mental force and moral elevation. she was the mother of two daughters and seven sons, her fifth child being peter, who was born in . to the end of his life, peter cooper had a clear recollection of many interesting events which occurred before the beginning of the present century. "i remember," he used to say, "that i was about nine years old at the time when washington was buried. that is, he was buried at mount vernon; but we had a funeral service in old st. paul's. i stood in front of the church, and i recall the event well, on account of his old white horse and its trappings." a poor hatter, with a family of nine children, must needs turn his children to account, and the consequence was that peter cooper enjoyed an education which gave him at least great manual dexterity. he learned how to use both his hands and a portion of his brain. he learned how to do things. his earliest recollection was his working for his father in pulling, picking, and cleaning the wool used in making hat-bodies, and he was kept at this work during his whole boyhood, except that one year he went to school half of every day, learning a little arithmetic, as well as reading and writing. by the time he was fifteen years old he had learned to make a good beaver hat throughout, and a good beaver hat of that period was an elaborate and imposing structure. then his father abandoned his hat shop and removed to peekskill on the hudson, where he set up a brewery, and where peter learned the whole art and mystery of making beer. he was quick to learn every kind of work, and even as a boy he was apt to suggest improvements in tools and methods. at the age of seventeen, he was still working in the brewery, a poor man's son, and engaged in an employment which for many and good reasons he disliked. brewing beer is a repulsive occupation. then, with his father's consent, he came alone to new york, intending to apprentice himself to any trade that should fake his fancy. he visited shop after shop, and at last applied for employment at a carriage factory near the corner of broadway and chambers street. he remembered, to his ninetieth year, the substance of the conversation which passed between him and one of the partners in this business. "have you room for an apprentice?" asked peter. "do you know anything about the business?" was the rejoinder. the lad was obliged to answer that he did not. "have you been brought up to work?" he replied by giving a brief history of his previous life. "is your father willing that you should learn this trade?" "he has given me my choice of trades." "if i take you, will you stay with me and work out your time?" he gave his word that he would, and a bargain was made--twenty-five dollars a year, and his board. he kept his promise and served out his time. to use his own language:-- "in my seventeenth year i entered as apprentice to the coach-making business, in which i remained four years, till i became 'of age.' i made for my employer a machine for mortising the hubs of carriages, which proved very profitable to him, and was, perhaps, the first of its kind used in this country. when i was twenty-one years old my employer offered to build me a shop and set me up in business, but as i always had a horror of being burdened with debt, and having no capital of my own, i declined his kind offer. he himself became a bankrupt. i have made it a rule to pay everything as i go. if, in the course of business, anything is due from me to any one, and the money is not called for, i make it my business oh the last saturday before christmas to take it to his business place." it was during this period of his life, from seventeen to twenty-one, that he felt most painfully the defects of his education. he had acquired manual skill, but he felt acutely that this quality alone was rather that of a beaver than of a man. he had an inquisitive, energetic understanding, which could not be content without knowledge far beyond that of the most advanced beaver. hungering for such knowledge, he bought some books: but in those days there were few books of an elementary kind adapted to the needs of a lonely, uninstructed boy. his books puzzled more than they enlightened him; and so, when his work was done, he looked about the little bustling city to see if there was not some kind of evening school in which he could get the kind of help he needed. there was nothing of the kind, either in new york or in any city then. nor were there free schools of any kind. he found a teacher, however, who, for a small compensation, gave him instruction in the evening in arithmetic and other branches. it was at this time that he formed the resolution which he carried out forty-five years later. he said to himself:-- "if ever i prosper in business so as to acquire more property than i need, i will try to found an institution in the city of new york, wherein apprentice boys and young mechanics shall have a chance to get knowledge in the evening." this purpose was not the dream of a sentimental youth. it was a clear and positive intention, which he kept steadily in view through all vicissitudes until he was able to enter upon its accomplishment. he was twenty-one years of age when the war of began, which closed for the time every carriage manufactory in the country. he was therefore fortunate in not having accepted the proposition of his employer. during the first months of the war business was dead; but as the supply of foreign merchandise gave out an impulse was given to home manufacture, especially of the fabrics used in clothing. there was a sudden demand for cloth-making machinery of all kinds, and now peter cooper put to good use his inventive faculty. he contrived a machine for cutting away the nap on the surface of cloth, which answered so well that he soon had a bustling shop for making the machines, which he sold faster than he could produce. he found himself all at once in an excellent business, and in december, , he married miss sarah bedel of hempstead, long island; he being then twenty-two and she twenty-one. there never was a happier marriage than this. to old age, he never sat near her without holding her hand in his. he never spoke to her nor of her without some tender epithet. he attributed the great happiness of his life and most of his success to her admirable qualities. he used to say that she was "the day-star, the solace, and the inspiration" of his life. she seconded every good impulse of his benevolence, and made the fulfillment of his great scheme possible by her wise and resolute economy. they began their married life on a scale of extreme frugality, both laboring together for the common good of the family. "in early life," he used to say, "when i was first married, i found it necessary to rock the cradle, while my wife prepared our frugal meals. this was not always convenient in my busy life, and i conceived the idea of making a cradle that would be made to rock by mechanism. i did so, and enlarging upon my first idea, i arranged the mechanism for keeping off the flies, and playing a music-box for the amusement of the baby! this cradle was bought of me afterwards by a delighted peddler, who gave me his 'whole stock in trade' for the exchange and the privilege of selling the patent in the state of connecticut." this device in various forms and modifications is still familiar in our households. they had six children, of whom two survive, mr. edward cooper, recently mayor of new york, and sarah, wife of hon. abram s. hewitt, member of congress from the city of new york. for nearly sixty-five years this couple lived together in happy marriage. in the peace with great britain, which gave such ecstasies of joy to the whole country, ruined peter cooper's business; as it was no longer possible to make cloth in the united states with profit. with three trades at his finger ends, he now tried a fourth, cabinet-making, in which he did not succeed. he moved out of town, and bought the stock of a grocer, whose store stood on the very site of the present cooper institute, at that time surrounded by fields and vacant lots. but even then he thought that, by the time he was ready to begin his evening school, that angle of land would probably be an excellent central spot on which to build it. he did very well with his grocery store; but it never would have enabled him to endow his institute. one day when he had kept his grocery about a year, and used his new cradle at intervals in the rooms above, an old friend of his accosted him, as he stood at the door of the grocery. "i have been building," said his visitor, "a glue factory for my son; but i don't think that either he or i can make it pay. but you are the very man to do it." "i'll go and see it," said peter cooper. he got into his friend's wagon and they drove to the spot, which was near the corner of madison avenue and twenty-ninth street, almost on the very spot now occupied by an edifice of much note called "the little church round the corner." he liked the look of the new factory, and he saw no reason why the people of new york should send all the way to russia for good glue. his friend asked two thousand dollars for the establishment as it stood, and peter cooper chanced to have that sum of money, and no more. he bought the factory on the spot, sold his grocery soon, and plunged into the manufacture of glue, of which he knew nothing except that russian glue was very good and american very bad. now he studied the composition of glue, and gradually learned the secret of making the best possible article which brought the highest price in the market. he worked for twenty years without a book-keeper, clerk, salesman, or agent. he rose with the dawn. when his men came at seven o'clock to work, they found the factory fires lighted, and it was the master who had lighted them. he watched closely and always the boiling of his glue, and at mid-day, when the critical operation was over, he drove into the city and went the round of his customers, selling them glue and isinglass, and passed the evening in posting his books and reading to his family. he developed the glue business until it yielded him a profit of thirty thousand dollars a year. he soon began to feel himself a capitalist, and to count the years until he would be able to begin the erection of the institution he had in his mind. but men who are known to have capital are continually solicited to embark in enterprises, and he was under a strong temptation to yield to such solicitations, for the scheme which he had projected would involve a larger expenditure than could be ordinarily made from one business in one lifetime. he used to tell the story of his getting into the business of making iron, which was finally a source of great profit to him. "in ," he would say, "i bought three thousand acres of land within the city limits of baltimore for $ , . when i first purchased the property it was in the midst of a great excitement created by a promise of the rapid completion of the baltimore and ohio railroad, which had been commenced by a subscription of five dollars per share. in the course of the first year's operations they had spent more than the five dollars per share. but the road had to make so many short turns in going around points of rocks that they found they could not complete the road without a much larger sum than they had supposed would be necessary; while the many short turns in the road seemed to render it entirely useless for locomotive purposes. the principal stockholders had become so discouraged that they said they would not pay any more, and would lose all they had already paid in. after conversing with them, i told them that if they would hold on a little while i would put a small locomotive on the road, which i thought would demonstrate the practicability of using steam-engines on the road, even with all the short turns in it. i got up a small engine for that purpose, and put it upon the road, and invited the stockholders to witness the experiment. after a good deal of trouble and difficulty in accomplishing the work, the stockholders came, and thirty-six men were taken into a car, and, with six men on the locomotive, which carried its own fuel and water, and having to go up hill eighteen feet to a mile, and turn all the short turns around the points of rocks, we succeeded in making the thirteen miles, on the first passage out, in one hour and twelve minutes, and we returned from ellicott's mills to baltimore in fifty-seven minutes. this locomotive was built to demonstrate that cars could be drawn around short curves, beyond anything believed at that time to be possible. the success of this locomotive also answered the question of the possibility of building railroads in a country scarce of capital, and with immense stretches of very rough country to pass, in order to connect commercial centres, without the deep cuts, the tunneling and leveling which short curves might avoid. my contrivance saved this road from bankruptcy." he still had his tract of baltimore land upon his hands, which the check to the prosperity of the city rendered for the time almost valueless; so he determined to build ironworks upon it, and a rolling-mill. in his zeal to acquire knowledge at first hand, he had a narrow escape from destruction in baltimore. "in my efforts to make iron," he said, "i had to begin by burning the wood growing upon the spot into charcoal, and in order to do that, i erected large kilns, twenty-five feet in diameter, twelve feet high, circular in form, hooped around with iron at the top, arched over so as to make a tight place in which to put the wood, with single bricks left out in different places in order to smother the fire out when the wood was sufficiently burned. after having burned the coal in one of these kilns perfectly, and believing the fire entirely smothered out, we attempted to take the coal out of the kiln; but when we had got it about half-way out, the coal itself took fire, and the men, after carrying water some time to extinguish it, gave up in despair. i then went myself to the door of the kiln to see if anything more could be done, and just as i entered the door the gas itself took fire and enveloped me in a sheet of flame. i had to run some ten feet to get out, and in doing so my eyebrows and whiskers were burned, and my fur hat was scorched down to the body of the fur. how i escaped i know not. i seemed to be literally blown out by the explosion, and i narrowly escaped with my life." the ironworks were finally removed to trenton, new jersey, where to this day, under the vigorous management of mr. hewitt and his partners, they are very successful. during these active years peter cooper never for a moment lost sight of the great object of his life. we have a new proof of this, if proof were needed, in the autobiography recently published of the eloquent orville dewey, pastor of the unitarian church of the messiah, which peter cooper attended for many years. "there were two men," says dr. dewey, "who came to our church whose coming seemed to be by chance, but was of great interest to me, for i valued them greatly. they were peter cooper and joseph curtis.[ ] neither of them then belonged to any religious society, or regularly attended any church. they happened to be walking down broadway one sunday evening, as the congregation were entering stuyvesant hall, where we then temporarily worshiped, and they said:-- "'let us go in here and see what _this_ is.' "when they came out, as they both told me, they said to one another:-- "'this is the place for _us_!' "and they immediately connected themselves with the congregation, to be among its most valued members. peter cooper was even then meditating that plan of a grand educational institute which he afterwards carried out. he was engaged in a large and successful business, and his one idea--which he often discussed with me--was to obtain the means of building that institute. a man of the gentlest nature and the simplest habits; yet his religious nature was his most remarkable quality. it seemed to breathe through his life as fresh and tender as if it were in some holy retreat, instead of a life of business." indeed there are several aged new yorkers who can well remember hearing mr. cooper speak of his project at that period. after forty years of successful business life, he found, upon estimating his resources, that he possessed about seven hundred thousand dollars over and above the capital invested in his glue and iron works. already he had become the owner of portions of the ground he had selected so long ago for the site of his school. the first lot he bought, as mr. hewitt informs me, about thirty years before he began to build, and from that time onward he continued to buy pieces of the ground as often as they were for sale, if he could spare the money; until in the whole block was his own. at first his intention was merely to establish and endow just such an evening school as he had felt the need of when he was an apprentice boy in new york. but long before he was ready to begin, there were free evening schools as well as day schools in every ward of the city, and he therefore resolved to found something, he knew not what, which should impart to apprentices and young mechanics a knowledge of the arts and sciences underlying the ordinary trades, such as drawing, chemistry, mechanics, and various branches of natural philosophy. while he was revolving this scheme in his mind he happened to meet in the street a highly accomplished physician who had just returned from a tour in europe, and who began at once to describe in glowing words the polytechnic school of paris, wherein mechanics and engineers receive the instruction which their professions require. the doctor said that young men came from all parts of france and lived on dry bread, just to attend the polytechnic. he was no longer in doubt; he entered at once upon the realization of his project. beginning to build in , he erected a massive structure of brick, stone, and iron, six stories in height, and fire-proof in every part, at a cost of seven hundred thousand dollars, the savings of his lifetime up to that period. five years after, he delivered the complete structure, with the hearty consent of his wife, his children, and his son-in-law, into the hands of trustees, thus placing it beyond his own control forever. two thousand pupils at once applied for admission. from that day to this the institute has continued from year to year to enlarge its scope and improve its methods. mr. cooper added something every year to its resources, until his entire gift to the public amounted to about two millions of dollars. peter cooper lived to the great age of ninety-two. no face in new york was more familiar to the people, and surely none was so welcome to them as the benign, placid, beaming countenance of "old peter cooper." the roughest cartman, the most reckless hack driver would draw up his horses and wait without a word of impatience, if it was peter cooper's quaint old gig that blocked the way. he was one of the most uniformly happy persons i have ever met, and he retained his cheerfulness to the very end. being asked one day in his ninetieth year, how he had preserved so well his bodily and mental vigor, he replied:-- "i always find something to keep me busy; and to be doing something for the good of man, or to keep the wheels in motion, is the best medicine one can take. i run up and down stairs here almost as easily as i did years ago, when i never expected that my term would run into the nineties. i have occasional twinges from the nervous shock and physical injury sustained from an explosion that occurred while i was conducting some experiments with nitrogen gas years ago. in other respects my days pass as painlessly as they did when i was a boy carrying a grocer's basket about the streets. it is very curious, but somehow, though i have none, of the pains and troubles that old men talk about, i have not the same luxury of life--the same relish in the mere act of living--that i had then. age is like babyhood come back again in a certain way. even the memories of baby-life come back--the tricks, the pranks, the boyish dreams; and things that i did not remember at forty or fifty years old i recollect vividly now. but a boy of ninety and a boy of nine are very different things, none the less. i never felt better in my life except for twinges occasioned by my nitrogen experiment. but still i hear a voice calling to me, as my mother often did, when i was a boy 'peter, peter, it is about bed-time,' and i have an old man's presentiment that i shall be taken soon." he loved the institute he had founded to the last hour of his consciousness. a few weeks before his death he said to reverend robert collyer:-- "i would be glad to have four more years of life given me, for i am anxious to make some additional improvements in cooper union, and then part of my life-work would be complete. if i could only live four years longer i would die content." dr. collyer adds this pleasing anecdote:-- "i remember a talk i had with him not long before his death, in which he said that a presbyterian minister of great reputation and ability, but who has since died, had called upon him one day and among other things discussed the future life. they were old and tried friends, the minister and mr. cooper, and when the clergyman began to question mr. cooper's belief, he said: 'i sometimes think that if one has too good a time here below, there is less reason for him to go to heaven. i have had a very good time, but i know poor creatures whose lives have been spent in a constant struggle for existence. they should have some reward hereafter. they have worked here; they should be rewarded after death. the only doubts that i have about the future are whether i have not had too good a time on earth.'" he died in april, , from a severe cold which he had not the strength to throw off. his end was as peaceful and painless as his life had been innocent and beneficial. [ ] a noted philanthropist of that day, devoted to the improvement of the public schools of the city. paris-duverney. french financier. some one has remarked that the old french monarchy was a despotism tempered by epigrams. i take the liberty of adding that if the despotism of the later french kings had not been frequently tempered by something more effectual than epigrams, it would not have lasted as long as it did. what tempered and saved it was, that, occasionally, by hook or by crook, men of sterling sense and ability rose from the ordinary walks of life to positions of influence and power, which enabled them to counteract the folly of the ruling class. about the year there was an inn at the foot of the alps, near the border line that divided france from switzerland, bearing the sign, st. francis of the mountain. there was no village near. the inn stood alone among the mountains, being supported in part by travelers going from france to geneva, and in part by the sale of wine to the farmers who lived in the neighborhood. the landlord, named paris, was a man of intelligence and ability, who, besides keeping his inn, cultivated a farm; assisted in both by energetic, capable sons, of whom he had four: antoine, aged twenty-three; claude, twenty-one; joseph, seven; and jean, an infant. it was a strong, able family, who loved and confided in one another, having no thought but to live and die near the spot upon which they were born, and in about the same sphere of life. but such was not their destiny. an intrigue of the french ministry drew these four sons from obscurity, and led them to the high places of the world. pontchartrain, whose name is still borne by a lake in louisiana, was then minister of finance to louis xiv. to facilitate the movements of the army in the war then going on between france and savoy, he proposed to the king the formation of a company which should contract to supply the army with provisions; and, the king accepting his suggestion, the company was formed, and began operations. but the secretary of war took this movement of his colleague in high dudgeon, as the supply of the army, he thought, belonged to the war department. to frustrate and disgrace the new company of contractors, he ordered the army destined to operate in italy to take the field on the first of may, several weeks before it was possible for the contractors by the ordinary methods to collect and move the requisite supplies. the company explained the impossibility of their feeding the army so early in the season; but the minister of war, not ill-pleased to see his rival embarrassed, held to his purpose, and informed the contractors' agent that he must have thirty thousand sacks of flour at a certain post by a certain day, or his head should answer it. the agent, alarmed, and at his wits' end, consulted the innkeeper of the alps, whom he knew to be an energetic spirit, and perfectly well acquainted with the men, the animals, the resources, and the roads of the region in which he lived, and through which the provisions would have to pass. the elder sons of the landlord were in the field at the time at work, and he told the agent he must wait a few hours till he could talk the matter over with them. at the close of the day there was a family consultation, and the result was that they undertook the task. antoine, the eldest son, went to lyons, the nearest large city, and induced the magistrates to lend the king the grain preserved in the public depositories against famine, engaging to replace it as soon as the navigation opened in the spring. the magistrates, full of zeal for the king's service, yielded willingly; and meanwhile, claude, the second of the brothers, bought a thousand mules; and, in a very few days, in spite of the rigor of the season, long lines of mules, each laden with a sack of flour, were winding their way through the defiles of the alps, guided by peasants whom the father of these boys had selected. this operation being insufficient, hundreds of laborers were set to work breaking the ice in the night, and in constructing barges, so as to be in readiness the moment navigation was practicable. early in the spring two hundred barge loads were set floating down toward the seat of war; and by the time the general in command was ready to take the field, there was an abundance of tents, provisions, ammunition, and artillery within easy reach. the innkeeper and his sons were liberally recompensed; and their talents thus being made known to the company of contractors, they were employed again a year or two after in collecting the means required in a siege, and in forwarding provisions to a province threatened with famine. these large operations gave the brothers a certain distaste for their country life, and they removed to paris in quest of a more stirring and brilliant career than an alpine inn with farm adjacent could afford. one of them enlisted at first in the king's guards, and the rest obtained clerkships in the office of the company of contractors. by the time they were all grown to manhood, the eldest, a man over forty, and the youngest, eighteen or twenty, they had themselves become army contractors and capitalists, noted in army circles for the tact, the fidelity, and the indomitable energy with which they carried on their business. the reader is aware that during the last years of the reign of louis xiv., france suffered a series of most disastrous defeats from the allied armies, commanded by the great english general, the duke of marlborough. it was these four able brothers who supplied the french army with provisions during that terrible time; and i do not hesitate to say, that, on two or three critical occasions, it was their energy and intelligence that saved the independence of their country. often the king's government could not give them a single louis-d'or in money when a famishing army was to be supplied. on several occasions they spent their whole capital in the work and risked their credit. there was one period of five months, as they used afterwards to say, when they never once went to bed _sure_ of being able to feed the army the next day. during those years of trial they were sustained in a great degree by the confidence which they inspired in their honesty, as well as in their ability. the great french banker and capitalist then was samuel bernard. on more than one occasion bernard saved them by lending them, on their personal security, immense sums; in one crisis as much as three million francs. we can judge of the extent of their operations, when we learn that, during the last two years of the war, they had to supply a hundred and eighty thousand men in the field, and twenty thousand men in garrison, while receiving from the government little besides depreciated paper. peace came at last; and it came at a moment when the whole capital of the four brothers was in the king's paper, and when the finances were in a state of inconceivable confusion. the old king died in , leaving as heir to the throne a sickly boy five years of age. the royal paper was so much depreciated that the king's promise to pay one hundred francs sold in the street for twenty-five francs. then came the scotch inflator, john law, who gave france a brief delirium of paper prosperity, ending with the most woful and widespread collapse ever known. it was these four brothers, but especially the third brother, joseph paris, known in french history as paris-duverney, who, by labors almost without example, restored the finances of the country, funded the debt at a reasonable interest, and enabled france to profit by the twenty years of peace that lay before her. there is nothing in the whole history of finance more remarkable than the five years' labors of these brothers after the law-mania of ; and it is hardly possible to overstate the value of their services at a time when the kingdom was governed by an idle and dissolute regent, and when there was not a nobleman about the court capable of grappling with the situation. the regent died of his debaucheries in the midst of their work. the duke of bourbon succeeded him; he was governed by madame de prie; and between them they concocted a nice scheme for getting the young king married, who had then reached the mature age of fifteen. the idea was to rule the king through a queen of their own choosing, and who would be grateful to them for her elevation. but it turned out quite otherwise. the king, indeed, was married, and he was very fond of his wife, and she tried to carry out the desires of those who had made her queen of france. but there was an obstacle in the way; and that obstacle was the king's unbounded confidence in his tutor, the abbé de fleury, a serene and extremely agreeable old gentleman past seventy. a struggle arose between the old tutor and madame de prie for the possession of the young king. the tutor won the victory. the duke of bourbon was exiled to his country-seat, and madame de prie was sent packing. paris-duverney and his first clerk were put into the bastille, where they were detained for two years in unusually rigorous imprisonment, and his three brothers were exiled to their native province. another intrigue of court set them free again, and the four brothers were once more in paris, where they continued their career as bankers, contractors, and capitalists as long as they lived, each of them acquiring and leaving a colossal fortune, which their heirs were considerate enough to dissipate. it was paris-duverney who suggested and managed the great military school at paris, which still exists. it was he also who helped make the fortunes of the most celebrated literary men of his time, voltaire and beaumarchais. he did this by admitting them to a share in army contracts, one of which yielded voltaire a profit of seven hundred thousand francs, which, with good nursing, made him at last the richest literary man that ever lived. paris-duverney was as good a man and patriot as a man could well be who had to work with and under such persons as louis xv. and madame de pompadour. by way of showing what difficulties men had to overcome who then desired to serve their country, i will mention a single incident of his later career. his favorite work, the École militaire, of which he was the first superintendent, shared the unpopularity of its early patron, madame de pompadour, and long he strove in vain to bring it into favor. to use the narrative of m. de loménie, the biographer of beaumarchais:-- "he was constantly at court, laboring without cessation on behalf of the military school, and soliciting the king in vain to visit it in state, which would have given a sort of _prestige_. coldly received by the dauphin, the queen, and the princesses, he could not, as the friend of madame de pompadour, obtain from the nonchalance of louis xv. the visit which he so much desired, when the idea struck him, in his despair, of having recourse to the young harpist, who appeared to be so assiduous in his attendance on the princesses, and who directed their concert every week. beaumarchais understood at once the advantage he might derive from rendering an important service to a clever, rich, old financier, who had still a number of affairs in hand, and who was capable of bringing him both wealth and advancement. but how could a musician without importance hope to obtain from the king what had already been refused to solicitations of much more influence than his own? beaumarchais went to work like a man who had a genius for dramatic intrigue and a knowledge of the human heart. "we have shown that, while he was giving his time and attention to the princesses, he never asked for anything in return. he thought that if he were fortunate enough to persuade them, in the first instance, to pay a visit to the École militaire, the curiosity of the king perhaps would be excited by the narrative of what they had seen, and would lead him to do that which he would never have been prompted to do by justice. he accordingly represented to the princesses not only the equitable side of the question, but also the immense interest which he himself had in obtaining this favor for a man who might be of great use to him. the princesses consented to visit the École militaire, and beaumarchais was granted the honor of accompanying them. the director received them with great splendor; they did not conceal from him the great interest they took in their young _protégé_, and some days afterward louis xv., urged by his daughters, visited it himself, and thus gratified the wishes of old duverney. "from this moment the financier, grateful for beaumarchais' good services, and delighted to find a person who could assist him as an intermediary in his intercourse with the court, resolved to make the young man's fortune. he began by giving him a share in one of his speculations to the amount of sixty thousand francs, on which he paid him interest at the rate of ten per cent.; after this, he gave him an interest in various other affairs. 'he initiated me,' says beaumarchais, 'into the secrets of finance, of which, as every one knows, he was a consummate master.'" such was government in the good old times! i like to think of it when things go amiss in washington or albany. let our rulers do as badly as they may, they cannot do worse than the rulers of the world did a century and a half ago. if any good or great thing was done in those days, it was done in spite of the government. sir rowland hill. the poet coleridge, on one of his long walks among the english lakes, stopped at a roadside inn for dinner, and while he was there the letter-carrier came in, bringing a letter for the girl who was waiting upon him. the postage was a shilling, nearly twenty-five cents. she looked long and lovingly at the letter, holding it in her hand, and then gave it back to the man, telling him that she could not afford to pay the postage. coleridge at once offered the shilling, which the girl after much hesitation accepted. when the carrier was gone she told him that he had thrown his shilling away, for the pretended letter was only a blank sheet of paper. on the outside there were some small marks which she had carefully noted before giving the letter back to the carrier. those marks were the _letter_, which was from her brother, with whom she had agreed upon a short-hand system by which to communicate news without expense. "we are so poor," said she to the poet, "that we have invented this manner of corresponding and sending our letters free." [illustration: sir rowland hill.] the shilling which the postman demanded was, in fact, about a week's wages to a girl in her condition fifty years ago. nor was it poor girls only who then played tricks upon the post-office. envelopes franked by honorable members of parliament were a common article of merchandise, for it was the practice of their clerks and servants to procure and sell them. indeed, the postal laws were so generally evaded that, in some large towns, the department was cheated of three quarters of its revenue. who can wonder at it? it cost more then to send a letter from one end of london to the other, or from new york to harlem, than it now does to send a letter from egypt to san francisco. the worst effect of dear postage was the obstacles it placed in the way of correspondence between poor families who were separated by distance. it made correspondence next to impossible between poor people in europe and their relations in america. think of an irish laborer who earned sixpence a day paying _seventy-five cents_ to get news from a daughter in cincinnati! it required the savings of three or four months. the man who changed all this, sir rowland hill, died only three years ago at the age of eighty-three. i have often said that an american ought to have invented the new postal system; and rowland hill, though born and reared in england, and descended from a long line of english ancestors, was very much an american. he was educated on the american plan. his mind was american, and he had the american way of looking at things with a view to improving them. his father was a birmingham schoolmaster, a free trader, and more than half a republican. he brought up his six sons and two daughters to use their minds and their tongues. his eldest son, the recorder of birmingham, once wrote of his father thus:-- "perhaps the greatest obligation we owe our father is this: that, from infancy, he would reason with us, and so observe all the rules of fair play, that we put forth our little strength without fear. arguments were taken at their just weight; the sword of authority was not thrown into the scale." miss edgeworth's tales deeply impressed the boy, and he made up his mind in childhood to follow the path which she recommended, and do something which should greatly benefit mankind. at the age of eleven he began to assist in teaching his father's pupils. at twelve he was a pupil no more, and gave himself wholly up to teaching. long before he was of age he had taken upon himself all the mere business of the school, and managed it so well as to pay off debts which had weighed heavily upon the family ever since he was born. at the same time he invented new methods of governing the school. he was one of the first to abolish corporal punishment. he converted his school into a republic governed by a constitution and code of laws, which filled a printed volume of more than a hundred pages, which is still in the possession of his family. his school, we are told, was governed by it for many years. if a boy was accused of a fault, he had the right of being tried by a jury of his school-fellows. monitors were elected by the boys, and these monitors met to deliberate upon school matters as a little parliament. upon looking back in old age upon this wonderful school, he doubted very much whether the plan was altogether good. the democratic idea, he thought, was carried too far; it made the boys too positive and argumentative. "i greatly doubt," said he once, "if i should send my own son to a school conducted on such a complicated system." it had, nevertheless, admirable features, which he originated, and which are now generally adopted. toward middle life he became tired of this laborious business, though he had the largest private school in that part of england. his health failed, and he felt the need of change and rest. having now some leisure upon his hands he began to invent and project. his attention was first called to the postal system merely by the high price of postage. it struck him as absurd that it should cost thirteen pence to convey half an ounce of paper from london to birmingham, while several pounds of merchandise could be carried for sixpence. upon studying the subject, he found that the mere carriage of a letter between two post-offices cost scarcely anything, the chief expense being incurred at the post-offices in starting and receiving it. he found that the actual cost of conveying a letter from london to edinburgh, four hundred and four miles, was _one eighteenth of a cent_! this fact it was which led him to the admirable idea of the uniform rate of one penny--for all distances. at that time a letter from london to edinburgh was charged about twenty-eight cents; but if it contained the smallest inclosure, even half a banknote, or a strip of tissue paper, the postage was doubled. in short, the whole service was incumbered with absurdities, which no one noticed because they were old. in , after an exhaustive study of the whole system, he published his pamphlet, entitled post-office reforms, in which he suggested his improvements, and gave the reasons for them. the post-office department, of course, treated his suggestions with complete contempt. but the public took a different view of the matter. the press warmly advocated his reforms. the thunderer of the london "times" favored them. petitions poured into parliament. daniel o'connell spoke in its favor. "consider, my lord," said he to the premier, "that a letter to ireland and the answer back would cost thousands upon thousands of my poor and affectionate countrymen more than a fifth of their week's wages. if you shut the post-office to them, which you do now, you shut out warm hearts and generous affections from home, kindred, and friends." the ministry yielded, and on january , , penny postage became the law of the british empire. as the whole postal service had to be reorganized, the government offered rowland hill the task of introducing the new system, and proposed to give him five hundred pounds a year for two years. he spurned the proposal, and offered to do the work for nothing. he was then offered fifteen hundred pounds a year for two years, and this he accepted rather than see his plan mismanaged by persons who did not believe in it. after many difficulties, the new system was set in motion, and was a triumphant success from the first year. a tory ministry coming in, they had the incredible folly to dismiss the reformer, and he retired from the public service without reward. the english people are not accustomed to have their faithful servants treated in that manner, and there was a universal burst of indignation. a national testimonial was started. a public dinner was given him, at which he was presented with a check for sixty-five thousand dollars. he was afterwards placed in charge of the post-office department, although with a lord over his head as nominal chief. this lord was a tory of the old school, and wished to use the post-office to reward political and personal friends. rowland hill said:-- "no, my lord; appointment and promotion for merit only." they quarreled upon this point, and rowland hill resigned. the queen sent a message to the house of commons asking for twenty thousand pounds as a national gift to sir rowland hill, which was granted, and he was also allowed to retire from office upon his full salary of two thousand pounds a year. that is the way to treat a public benefactor; and nations which treat their servants in that spirit are likely to be well served. the consequences of this postal reform are marvelous to think of. the year before the new plan was adopted in great britain, one hundred and six millions of letters and papers were sent through the post-office. year before last the number was one thousand four hundred and seventy-eight millions. in other words, the average number of letters per inhabitant has increased from three per annum to thirty-two. the united states, which ought to have taken the lead in this matter, was not slow to follow, and every civilized country has since adopted the system. a few weeks before sir rowland hill's death, the freedom of the city of london was presented to him in a gold box. he died in august, , full of years and honors. marie-antoine carÈme, french cook. domestic servants occupy in france a somewhat more elevated position in the social scale than is accorded them in other countries. as a class, too, they are more intelligent, better educated, and more skillful than servants elsewhere. there are several works in the french language designed expressly for their instruction, some of the best of which were written, or professed to have been written, by servants. on the counter of a french bookstore you will sometimes see such works as the following: "the perfect coachman," "the life of jasmin, the good laquey," "rules for the government of shepherds and shepherdesses, by the good shepherd," "the well-regulated household," "duties of servants of both sexes toward god and toward their masters and mistresses, by a servant," "how to train a good-domestic." some books of this kind are of considerable antiquity and have assisted in forming several generations of domestic servants. one of them, it is said, entitled, "the perfect coachman," was written by a prince of the reigning house of france. in france, as in most old countries, few people expect to change their condition in life. once a servant, always a servant. it is common for parents in humble life to apprentice their children to some branch of domestic service, satisfied if they become excellent in their vocation, and win at length the distinctions and promotions which belong to it. lady morgan, who visited paris several years ago, relates an anecdote or two showing how intelligent some french servants are. she was walking along the quai voltaire, followed by her french lackey, when he suddenly came to her side and, pointing to a house, said:-- "there, madam, is a house consecrated to genius. there died voltaire--in that apartment with the shutters closed. there died the first of our great men; perhaps also the last." on another occasion the same man objected to a note which she had written in the french language. "is it not good french, then?" asked the lady. "oh, yes, madam," replied he; "the french is very good, but the style is too cold. you begin by saying, you _regret_ that you cannot have the pleasure. you should say, i am _in despair_." "well, then," said lady morgan, "write it yourself." "you may write it, if you please, my lady, at my dictation, for as to reading and writing, they are branches of my education which were totally neglected." the lady remarks, however, that paris servants can usually read very well, and that hackmen, water-carriers, and porters may frequently be seen reading a classical author while waiting for a customer. a very remarkable case in point is marie-antoine carème, whom a french writer styles, "one of the princes of the culinary art." i suppose that no country in the world but france could produce such a character. of this, however, the reader can judge when i have briefly told his story. he was born in a paris garret, in , one of a family of fifteen children, the offspring of a poor workman. as soon as he was old enough to render a little service, his father placed him as a garçon in a cheap and low restaurant, where he received nothing for his labor except his food. this was an humble beginning for a "prince." but he improved his disadvantages to such a degree that, at the age of twenty, he entered the kitchen of talleyrand. now prince talleyrand, besides being himself one of the daintiest men in europe, had to entertain, as minister of foreign affairs, the diplomatic corps, and a large number of other persons accustomed from their youth up to artistic cookery. carème proved equal to the situation. talleyrand's dinners were renowned throughout europe and america. but this cook of genius, not satisfied with his attainments, took lessons in the art from guipière, the renowned _chef_ of the emperor napoleon--he who followed murat into the wilds of russia and perished with so many other cooks and heroes. carème appears to have succeeded guipière in the imperial kitchen, but he did not follow the emperor to elba. when the allied kings celebrated their triumph in paris at a grand banquet, it was carème who, as the french say, "executed the repast." his brilliant success on this occasion was trumpeted over europe, and after the final downfall of napoleon he was invited to take charge of the kitchen of the english prince regent. at various times during his career he was cook to the emperor alexander of russia, to the emperor of austria, to the prince of wurtemberg, and to the head of the house of rothschild. in the service of these illustrious eaters he gained large sums of money, which, however, he was very far from hoarding. in the maturity of his powers he devoted himself and his fortune to historical investigations concerning the art of cookery. for several years he was to be daily seen in the imperial library, studying the cookery, so renowned, of the ancient greeks and romans, desiring especially to know whether they possessed any secrets which had been lost. his conclusion was, that the dishes served upon the tables of lucullus, augustus cæsar, and others, were "utterly bad and atrociously stupid." but he commended the decoration of their tables, the cups and vases of gold, the beautiful pitchers, the chased silver, the candles of white spanish wax, the fabrics of silk whiter than the snow, and the beautiful flowers with which their tables were covered. he published the results of his labors in a large octavo volume, illustrated by a hundred and twenty-eight engravings. he continued his studious labors, and published at various periods "ancient and modern cookery compared," in two volumes, octavo, "the paris cook, or the art of cooking in the nineteenth century," and others. toward the close of his life, he wrote a magazine article upon napoleon's way of eating at st. helena. he dedicated one of his works to his great instructor and master in the art of cookery, guipière. to give the reader an idea of his way of thinking and feeling i will translate a few sentences of this dedication:-- "rise, illustrious shade! hear the voice of the man who was your admirer and your pupil! your distinguished talents brought upon you hatred and persecution. by cabal you were obliged to leave your beautiful native land, and go into italy to serve a prince (murat) to whose enjoyment you had once ministered in paris. you followed your king into russia. but alas, by a deplorable fatality, you perished miserably, your feet and body frozen by the frightful climate of the north. arrived at vilna, your generous prince lavished gold to save you, but in vain. o great guipière, receive the public homage of a faithful disciple. regardless of those who envied you, i wish to associate your name with my labors. i bequeath to your memory my most beautiful work. it will convey to future ages a knowledge of the elegance and splendor of the culinary art in the nineteenth century; and if vatel rendered himself illustrious by a point of honor, dear to every man of merit, your unhappy end, o guipière, renders you worthy of the same homage! it was that point of honor which made you follow your prince into russia, when your gray hairs seemed to assure you a happier destiny in paris. you shared the sad fate of our old veterans, and the honor of our warriors perishing of hunger and cold." all this, the reader will admit, is very strange and very french. in the same work, carème chronicles the names of all the celebrated cooks who perished in the retreat from russia. this prince of the kitchen died in , when he was scarcely fifty years of age. his works are still well known in france, and some of them have passed through more than one edition. it is an odd contradiction, that the name of this prince of the kitchen should be the french word for the time of fasting. carême means _lent_. wonderful walker. i have here a good story for hard times. it is of a clergyman and cotton spinner of the church of england, who, upon an income of twenty-four pounds a year, lived very comfortably to the age of ninety-four years, reared a family of eight children respectably, gave two of his sons a university education, and left an estate worth two thousand pounds. every one will admit that this was a good deal to do upon a salary of one hundred and twenty dollars; and some readers, who find the winter hard to get through, may be interested to know how he did it. to this day, though he has been dead one hundred years, he is spoken of in the region where he lived, as wonderful walker. by this epithet, also, he is spoken of by the poet wordsworth, in the "excursion:"-- "and him, the wonderful, our simple shepherds, speaking from the heart, deservedly have styled." he lived and died in the lake country of england, near the residence of wordsworth, who has embalmed him in verse, and described him in prose. robert walker, the youngest of twelve children, the son of a yeoman of small estate, was bred a scholar because he was of a frame too delicate, as his father thought, to earn his livelihood by bodily labor. he struggled into a competent knowledge of the classics and divinity, gained in strength as he advanced towards manhood, and by the time he was ordained was as vigorous and alert as most men of his age. after his ordination, he had his choice of two curacies of the same revenue, namely, five pounds a year--twenty-five dollars. one of these, seathwaite by name, too insignificant a place to figure upon a map, or even in the "gazetteer," was situated in his native valley, in the church of which he had gone to school in his childhood. he chose seathwaite, but not for that reason. he was in love; he wished to marry; and this parish had a small parsonage attached to it, with a garden of three quarters of an acre. the person to whom he was engaged was a comely and intelligent domestic servant such as then could frequently be found in the sequestered parts of england. she had saved, it appears, from her wages the handsome sum of forty pounds. thus provided, he married, and entered upon his curacy in his twenty-sixth year, and set up housekeeping in his little parsonage. every one knows what kind of families poor clergymen are apt to have. wonderful walker had one of that kind. about every two years, or less, a child arrived; and heartily welcome they all were, and deeply the parents mourned the loss of one that died. in the course of a few years, eight bouncing girls and boys filled his little house; and the question recurs with force: how did he support them all? from queen anne's bounty, and other sources, his income was increased to the sum mentioned above, twenty-four pounds. that for a beginning. now for the rest. in the first place, he was the lawyer of his parish, as well as its notary, conveyancer, appraiser, and arbitrator. he drew the wills, contracts, and deeds, charging for such services a moderate fee, which added to his little store of cash. his labors of this kind, at the beginning of the year, when most contracts were made, were often extremely severe, occupying sometimes half the night, or even all night. then he made the most of his garden, which was tilled by his own hands, until his children were old enough to help him. upon the mountains near by, having a right of pasturage, he kept two cows and some sheep, which supplied the family with all their milk and butter, nearly all their meat, and most of their clothes. he also rented two or three acres of land, upon which he raised various crops. in sheep-shearing time, he turned out and helped his neighbors shear their sheep, a kind of work in which he had eminent skill. as compensation, each farmer thus assisted gave him a fleece. in haying time, too, he and his boys were in the fields lending a hand, and got some good hay-cocks for their pains. besides all this, he was the schoolmaster of the parish. mr. wordsworth positively says that, during most of the year, except when farm work was very pressing, he taught school eight hours a day for five days in the week, and four hours on saturday. the school-room was the church. the master's seat was inside the rails of the altar; he used the communion table for a desk; and there, during the whole day, while the children were learning and saying their lessons, he kept his spinning-wheel in motion. in the evening, when school was over, feeling the need of exercise, he changed the small spinning-wheel at which he had sat all day for a large one, which required the spinner to step to and fro. there was absolutely no waste and no luxury known in his house. the only indulgence which looked like luxury was that, on a saturday afternoon, he would read a newspaper or a magazine. the clothes of the whole family were grown, spun, woven, and made by themselves. the fuel of the house, which was peat, was dug, dried, and carried by themselves. they made their own candles. once a month a sheep was selected from their little flock and killed for the use of the family, and in the fall a cow would be salted and dried for the winter, the hide being tanned for the family shoes. no house was more hospitable, nor any hand more generous, than those of this excellent man. old parishioners, who walked to church from a distance and wished to remain for the afternoon service, were always welcome to dinner at the parsonage, and sometimes these guests were so numerous that it took the family half the week to eat up the cold broken remains. he had something always to spare to make things decent and becoming. his sister's pew in the chapel he lined neatly with woolen cloth of his own making. "it is the only pew in the chapel so distinguished," writes the poet, "and i know of no other instance of his conformity to the delicate accommodations of modern times." nineteen or twenty years elapsed before this singular and interesting man attracted any public notice. his parishioners, indeed, held him in great esteem, for he was one of those men who are not only virtuous, but who render virtue engaging and attractive. if they revered him as a benevolent, a wise, and a temperate man, they loved him as a cheerful, friendly, and genial soul. he was gay and merry at christmas, and his goodness was of a kind which allures while it rebukes. but beyond the vale of seathwaite, he was unknown until the year , when a traveler discovered him, and published an account of his way of life. "i found him," writes this traveler, "sitting at the head of a long square table, dressed in a coarse blue frock, trimmed with black horn buttons, a checked shirt, a leathern strap about his neck for a stock, a coarse apron, a pair of great wooden soled shoes, plated with iron to preserve them, with a child upon his knee, eating his breakfast. his wife and the remainder of his children were, some of them, employed in waiting upon each other, the rest in teasing and spinning wool, at which trade he is a great proficient; and, moreover, when it is ready for sale, he will lay it upon his back, sixteen or thirty-two pounds' weight, and carry it on foot to the market, seven or eight miles." he spoke also of his cheerfulness, and the good humor which prevailed in the family, the simplicity of his doctrine, and the apostolic fervor of his preaching; for, it seems, he was an excellent preacher as well. the publication of this account drew attention to the extreme smallness of his clerical income, and the bishop offered to annex to seathwaite an adjacent parish, which also yielded a revenue of five pounds a year. by preaching at one church in the morning, and the other in the afternoon, he could serve both parishes, and draw both stipends. wonderful walker declined the bishop's offer. "the annexation," he wrote to the bishop, "would be apt to cause a general discontent among the inhabitants of both places, by either thinking themselves slighted, being only served alternately or neglected in the duty, or attributing it to covetousness; all of which occasions of murmuring i would willingly avoid." mr. wordsworth, to whom we are indebted for this letter, mentions that, in addition to his other gifts and graces, he had a "beautiful handwriting." this admirable man continued to serve his little parish for nearly sixty-eight years. his children grew up about him. two of his sons became clergymen of the church of england; one learned the trade of a tanner; four of his daughters were happily married; and, occasionally, all the children and grandchildren, a great company of healthy and happy people, spent christmas together, and went to church, and partook of the communion together, this one family filling the whole altar. the good old wife died first. at her funeral the venerable man, past ninety years of age, had the body borne to the grave by three of her daughters and one granddaughter. when the corpse was lifted, he insisted upon lending a hand, and he felt about (for he was almost blind) until he got held of a cloth that was fastened to the coffin; and thus, as one of the bearers of the body, he entered the church where she was to be buried. the old man, who had preached with much vigor and great clearness until then sensibly drooped after the loss of his wife. his voice faltered as he preached; he kept looking at the seat in which she had sat, where he had watched her kind and beautiful face for more than sixty years. he could not pass her grave without tears. but though sad and melancholy when alone, he resumed his cheerfulness and good-humor when friends were about him. one night, in his ninety-fourth year, he tottered upon his daughter's arm, as his custom was, to the door, to look out for a moment upon the sky. "how clear," said he, "the moon shines to-night." in the course of that night he passed peacefully away. at six the next morning he was found dead upon the couch where his daughter had left him. of all the men of whom i have ever read, this man, i think, was the most virtuous and the most fortunate. sir christopher wren. of the out-of-door sights of london, none makes upon the stranger's mind so lasting an impression as huge st. paul's, the great black dome of which often seems to hang over the city poised and still, like a balloon in a calm, while the rest of the edifice is buried out of sight in the fog and smoke. the visitor is continually coming in sight of this dome, standing out in the clearest outline when all lower objects are obscure or hidden. insensibly he forms a kind of attachment to it, at the expression of which the hardened old londoner is amused; for he may have passed the building twice a day for forty years without ever having had the curiosity to enter its doors, or even to cast a glance upwards at its sublime proportions. it is the verdant american who is penetrated to the heart by these august triumphs of human skill and daring. it is we who, on going down into the crypt of st. paul's, are so deeply moved at the inscription upon the tomb of the architect of the cathedral:-- "underneath is laid the builder of this church and city, christopher wren, who lived more than ninety years, not for himself, but for the public good. reader, if you seek his monument, look around!" the writer of this inscription, when he used the word _circumspice_, which we translate _look around_, did not intend probably to confine the reader's attention to st. paul's. much of the old part of london is adorned by proofs of wren's skill and taste; for it was he who rebuilt most of the churches and other public buildings which were destroyed by the great fire of london in . he built or rebuilt fifty-five churches in london alone, besides thirty-six halls for the guilds and mechanics' societies. the royal palaces of hampton court and kensington were chiefly his work. he was the architect of temple bar, drury lane theatre, the royal exchange, and the monument. it was he who adapted the ancient palace at greenwich to its present purpose, a retreat for old sailors. the beautiful city of oxford, too, contains colleges and churches constructed or reconstructed by him. it is doubtful if any other man of his profession ever did so much work, as he, and certainly none ever worked more faithfully. with all this, he was a self-taught architect. he was neither intended by his father to pursue that profession, nor did he ever receive instruction in it from an architect. he came of an old family of high rank in the church of england, his father, a clergyman richly provided with benefices, and his uncle being that famous bishop of ely who was imprisoned in the tower eighteen years for his adherence to the royal cause in the time of the commonwealth. he derived his love of architecture from his father, dr. christopher wren, a mathematician, a musician, a draughtsman, who liked to employ his leisure in repairing and decorating the churches under his charge. dr. wren had much mechanical skill, and devised some new methods of supporting the roofs of large buildings. he was the ideal churchman, bland, dignified, scholarly, and ingenious. his son christopher, born in (the year after boston was founded), inherited his father's propensities, with more than his father's talents. like many other children destined to enjoy ninety years of happy life, he was of such delicate health as to require constant attention from all his family to prolong his existence. as the years went on, he became sufficiently robust, and passed through westminster school to oxford, where he was regarded as a prodigy of learning and ability. john evelyn, who visited oxford when wren was a student there, speaks of visiting "that miracle of a youth, mr. christopher wren, nephew of the bishop of ely." he also mentions calling upon one of the professors, at whose house "that prodigious young scholar, mr. christopher wren," showed him a thermometer, "a monstrous magnet," some dials, and a piece of white marble stained red, and many other curiosities, some of which were the young scholar's own work. there never had been such an interest before in science and invention. the work of lord bacon in which he explained to the scholars of europe the best way of discovering truth (by experiment, comparison, and observation) was beginning to bear fruit. a number of gentlemen at oxford were accustomed to meet once a week at one another's houses for the purpose of making and reporting experiments, and thus accumulating the facts leading to the discovery of principles. this little social club, of which christopher wren was a most active and zealous member, grew afterwards into the famous royal society, of which sir isaac newton was president, and to which he first communicated his most important discoveries. all subjects seem to have been discussed by the oxford club except theology and politics, which were becoming a little too exciting for philosophic treatment. wren was in the fullest sympathy with the new scientific spirit, and during all the contention between king and parliament he and his friends were quietly developing the science which was to change the face of the world, and finally make such wasteful wars impossible. a mere catalogue of christopher wren's conjectures, experiments, and inventions, made while he was an oxford student, would more than fill the space i have at command. at the age of twenty-four he was offered a professorship of astronomy at oxford, which he modestly declined as being above his age, but afterwards accepted. his own astronomy was sadly deficient, for he supposed the circumference of our earth to be , miles. this, however, was before sir isaac newton had published the true astronomy, or had himself learned it. after a most honorable career as teacher of science at oxford, he received from the restored king, charles ii., the appointment of assistant to the surveyor general of works, an office which placed him in charge of public buildings in course of construction. it made him, in due time, the architect-general of england, and it was in that capacity that he designed and superintended very many of the long series of works mentioned above. there never was a more economical appointment. the salary which he drew from the king appears to have been two hundred pounds a year, a sum equal perhaps to four thousand of our present dollars. such was the modest compensation of the great architect who rebuilt london after the great fire. that catastrophe occurred a few years after his appointment. the fire continued to rage for nearly four days, during which it destroyed eighty-nine churches including st. paul's, thirteen thousand two hundred houses, and laid waste four hundred streets. christopher wren was then thirty-five years of age. he promptly exhibited to the king a plan for rebuilding the city, which proposed the widening and straightening of the old streets, suggested a broad highway along the bank of the river, an ample space about st. paul's, and many other improvements which would have saved posterity a world of trouble and expense. the government of the dissolute charles was neither wise enough nor strong enough to carry out the scheme, and sir christopher was obliged to content himself with a sorry compromise. the rest of his life was spent in rebuilding the public edifices, his chief work being the great cathedral. upon that vast edifice he labored for thirty-five years. when the first stone of it was laid, his son christopher was a year old. it was that son, a man of thirty-six, who placed the last stone of the lantern above the dome, in the presence of the architect, the master builder, and a number of masons. this was in the year . sir christopher lived thirteen years longer, withdrawn from active life in the country. once a year, however, it was his custom to visit the city, and sit for a while under the dome of the cathedral. he died peacefully while dozing in his arm-chair after dinner, in , aged ninety-two years, having lived one of the most interesting and victorious lives ever enjoyed by a mortal. if the people of london are proud of what was done by sir christopher wren, they lament perhaps still more what he was not permitted to do. they are now attempting to execute some of his plans. miss lucy phillimore, his biographer, says:-- "wren laid before the king and parliament a model of the city as he proposed to build it, with full explanations of the details of the design. the street leading up ludgate hill, instead of being the confined, winding approach to st. paul's that it now is, even its crooked picturesqueness marred by the viaduct that cuts all the lines of the cathedral, gradually widened as it approached st. paul's, and divided itself into two great streets, ninety feet wide at the least, which ran on either side of the cathedral, leaving a large open space in which it stood. of the two streets, one ran parallel with the river until it reached the tower, and the other led to the exchange, which wren meant to be the centre of the city, standing in a great piazza, to which ten streets each sixty feet wide converged, and around which were placed the post-office, the mint, the excise office, the goldsmiths' hall, and the insurance, forming the outside of the piazza. the smallest streets were to be thirty feet wide, 'excluding all narrow, dark alleys without thoroughfares, and courts.' "the churches were to occupy commanding positions along the principal thoroughfares, and to be 'designed according to the best forms for capacity and hearing, adorned with useful porticoes and lofty ornamental towers and steeples in the greater parishes. all church yards, gardens, and unnecessary vacuities, and all trades that use great fires or yield noisome smells to be placed out of town.' "he intended that the church yards should be carefully planted and adorned, and be a sort of girdle round the town, wishing them to be an ornament to the city, and also a check upon its growth. to burials within the walls of the town he strongly objected, and the experience derived from the year of the plague confirmed his judgment. no gardens or squares are mentioned in the plan, for he had provided, as he thought, sufficiently for the healthiness of the town by his wide streets and numerous open spaces for markets. gardening in towns was an art little considered in his day, and contemporary descriptions show us that 'vacuities' were speedily filled with heaps of dust and refuse. "the london bank of the thames was to be lined with a broad quay along which the halls of the city companies were to be built, with suitable warehouses in between for the merchants' to vary the effect of the edifices. the little stream whose name survives in _fleet_ street was to be brought to light, cleansed, and made serviceable as a canal one hundred and twenty feet wide, running much in the line of the present holborn viaduct." these were the wise and large thoughts of a great citizen for the metropolis of his country. but the king was charles ii.! our race produces good citizens in great numbers, and great citizens not a few, but the supreme difficulty of civilization is to get a few such where they can direct and control. sir john rennie, engineer. one of the most striking city scenes in the world is the view of london as you approach london bridge in one of the small, low-decked steamers which ply upon the thames. london stands where navigation for sea-going vessels ceases on this famous stream, which is crossed at london, within a stretch of three or four miles, by about fifteen bridges, of which seven or eight can be seen at one view under the middle arch of london bridge. over all these bridges there is a ceaseless tide of human life, and in the river below, besides long lines of ships at anchor and unloading, there are as many steam-vessels, barges, skiffs, and wherries as can find safe passage. a scene more animated, picturesque, and grand is nowhere else presented, especially when the great black dome of st. paul's is visible, hanging over it, appearing to be suspended in the foggy atmosphere like a black balloon, the cathedral itself being invisible. three of these bridges were built by the engineers, father and son, whose name appears at the head of this article, and those three are among the most wonderful structures of their kind. one of these is london bridge; another is called southwark, and the third, waterloo. the time may come when the man who builds bridges will be as celebrated as the man who batters them down with cannon; but, at present, for one person who knows the name of sir john rennie there are a thousand who are familiar with wellington and waterloo. he had, however, a pedigree longer than that of some lords. his father was a very great engineer before him, and that father acquired his training in practical mechanics under a scotch firm of machinists and mill-wrights which dates back to the reign of charles the second. it is to be particularly noted that both john rennie, the elder, and sir john, his son, derived an important part of their education in the workshop and model-room. both of them, indeed, had an ideal education; for they enjoyed the best theoretical instruction which their age and country could furnish, and the best practical training also. theory and practice went hand in hand. while the intellect was nourished, the body was developed, the hand acquired skill, and the eyesight, certainty. it is impossible to imagine a better education for a young man than for him to receive instruction at edinburgh university under the illustrious professor black, and afterwards a training in practical mechanics under andrew meikle, one of the best mechanics then living. this was the fortunate lot of rennie's father, who wisely determined that his son should have the same advantage. when the boy had passed through the preparatory schools, the question arose, whether he should be sent to one of the universities, or should go at once into the workshop. his father frequently said that the real foundation of civil engineering is mechanics, theoretical and practical. he did not believe that a young man could become an engineer by sitting in a class-room and hearing lectures; but that he must be placed in contact with realities, with materials, with tools, with men, with difficulties, make mistakes, achieve successes, and thus acquire the blended boldness and caution which mark the great men in this profession. it is a fact that the greatest engineers of the past century, whatever else they may have had or lacked, were thoroughly versed in practical mechanics. smeaton, telford, arkwright, hargreaves, george stephenson, rennie, were all men who, as they used to say, had "an ounce of theory to a pound of practice." young rennie worked eight hours a day in the practical part of his profession, and spent four in the acquisition of science and the modern languages, aided in both by the first men in london in their branches. four or five years of this training gave him, as he says in his autobiography, the "_rudiments_" of his profession. his father next determined to give him some experience in bearing responsibility, and placed him as an assistant to the resident-engineer of waterloo bridge, then in course of construction. he was but nineteen years of age; but, being the son of the head of the firm, he was naturally deferred to and prepared to take the lead. soon after, the southwark bridge was begun, which the young man superintended daily at every stage of its construction. english engineers regard this bridge as the _ne plus ultra_ of bridge-building. a recent writer speaks of it as "confessedly unrivaled as regards its colossal proportions, its architectural effect, or the general simplicity and massive character of its details." it crosses the river by three arches, of which the central one has a span of two hundred and forty feet, and it is built at a place where the river at high tide is thirty-six feet deep. the cost of this bridge was four millions of dollars, and it required five years to build it. the bridge is of iron, and contains a great many devices originated by the young engineer, and sanctioned by his father. it was he also who first, in recent times, learned how to transport masses of stone of twenty-five tons weight, used for the foundation of bridges. having thus become an accomplished engineer, his wise old father sent him on a long tour, which lasted more than two years, in the course of which he inspected all the great works, both of the ancients and moderns, in europe, and the more accessible parts of africa and asia. returning home, the death of his father suddenly placed upon his shoulders the most extensive and difficult engineering business in great britain. but with such a training, under such a father, and inheriting so many traditional methods, he proved equal to the position, continued the great works begun by his father, and carried them on to successful completion. his father had already convinced the government that the old london bridge could never be made sufficient for the traffic, or unobstructive to the navigation. a bridge has existed at this spot since the year , and some of the timbers of the original structure were still sound in , when work upon the new bridge was begun. thirty firms competed for the contract for building the new london bridge, but it was awarded to the rennies, under whose superintendence it was built. the bridge is nine hundred and twenty-eight feet in length, and has five arches. in this structure although utility was the first consideration, there in an elegant solidity of design which makes it pleasing and impressive in the highest degree. the rapid stream is as little obstructed as the circumstances admitted, and there does not appear to be in the bridge an atom of superfluous material. london bridge is, i suppose, the most crowded thoroughfare in the world. twenty-five thousand vehicles cross it daily, as well as countless multitudes of foot-passengers. so great is the throng, that there is a project now on foot to widen it. in , when it was formally opened by king william iv., the great engineer was knighted, and he was in consequence ever after called sir john rennie. during the period of railroad building, sir john rennie constructed a great many remarkable works, particularly in portugal and sweden. we have lately heard much of the disappointment of young engineers whom the cessation in the construction of railroads has thrown out of business. perhaps no profession suffered more from the dull times than this. sir john rennie explains the matter in his autobiography:-- "in ," he tells us, "the demand for engineering surveyors and assistants was very great. engineering was considered to be the only profession where immense wealth and fame were to be acquired, and consequently everybody became engineers. it was not the question whether they were educated for it, or competent to undertake it, but simply whether any person chose to dub himself engineer; hence lawyers' clerks, surgeons' apprentices, merchants, tradesmen, officers in the army and navy, private gentlemen, left their professions and became engineers. the consequence was that innumerable blunders were made and vast sums of money were recklessly expended." it was much the same in the united states; and hence a good many of these gentlemen have been obliged to find their way back to the homelier occupations which they rashly abandoned. but in our modern world a thoroughly trained engineer, like sir john rennie, will always be in request; for man's conquest of the earth is still most incomplete; and i do not doubt that the next century will far outdo this in the magnitude of its engineering works, and in the external changes wrought by the happy union of theory and practice in such men as telford, stephenson, and rennie. sir john rennie spent the last years of his life in writing his memoirs, a most interesting and useful work, recently published in london, which, i hope, will be republished here. it is just the book for a young fellow who has an ambition to gain honor by serving mankind in a skillful and manly way. sir john rennie, like his father before him, and like all other great masters of men, was constantly attentive to the interests and feelings of those who assisted him. he was a wise and considerate employer; and the consequence was, that he was generally served with loyal and affectionate fidelity. he died in , aged eighty years. sir moses montefiore. we still deal strangely with the jews. while at one end of europe an israelite scarcely dares show himself in the streets for fear of being stoned and abused, in other countries of the same continent we see them prime ministers, popular authors, favorite composers of music, capitalists, philanthropists, to whom whole nations pay homage. sir moses montefiore, though an english baronet, is an israelite of the israelites, connected by marriage and business with the rothschilds, and a sharer in their wonderful accumulations of money. his hundredth birthday was celebrated in at his country-house on the english coast, and celebrated in such a way as to make the festival one of the most interesting events of the year. the english papers tell us that nearly a hundred telegrams of congratulation and benediction reached the aged man in the course of the day, from america, africa, asia, and all-parts of europe, from christians, jews, mahomedans, and men of the world. the telegraph offices, we are told, were clogged during the morning with these messages, some of which were of great length, in foreign languages and in strange alphabets, such as the arabic and hebrew. friends in england sent him addresses in the english manner, several of which were beautifully written upon parchment and superbly mounted. the railroad passing near his house conveyed to him by every train during the day presents of rare fruit and beautiful flowers. the jews in spain and portugal forwarded presents of the cakes prepared by orthodox jews for the religious festival which occurred on his birthday. indeed, there has seldom been in europe such a widespread and cordial recognition of the birthday of any private citizen. doubtless, the remarkable longevity of sir moses had something to do with emphasizing the celebration. great wealth, too, attracts the regard of mankind. but there are many rich old jews in the world whose birthday excites no enthusiasm. the briefest review of the long life of sir moses montefiore will sufficiently explain the almost universal recognition of the recent anniversary. he was born as long ago as , the second year of american independence, when william pitt was prime minister of england. he was five years old when the bastille was stormed, and thirty-one when the battle of waterloo was fought. he was in middle life before england had become wise enough to make jew and christian equal before the law, and thus attract to her shores one of the most gifted and one of the most virtuous of races. the father of sir moses lived and died in one of the narrow old streets near the centre of london called philpot lane, where he became the father of an old-fashioned family of seventeen children. this prolific parent was a man of no great wealth, and consequently his eldest son, moses, left school at an early age, and was apprenticed to a london firm of provision dealers. he was a singularly handsome young man, of agreeable manners and most engaging disposition, circumstances which led to his entering the stock exchange. this was at a time when only twelve jewish brokers were allowed to carry on business in london, and he was one of the twelve. at the age of twenty-eight he had fully entered upon his career, a broker and a married man, his wife the daughter of levy cohen, a rich and highly cultivated jewish merchant. his wife's sister had married n. m. rothschild, and one of his brothers married rothschild's sister. united thus by marriage to the great banker, he became also his partner in business, and this at a time when the gains of the rothschilds were greatest and most rapid. most readers remember how the rothschilds made their prodigious profits during the last years of bonaparte's reign. they had a pigeon express at dover, by means of which they obtained the first correct news from the continent. during the "hundred days," for example, such a panic prevailed in england that government bonds were greatly depressed. the first rumors from waterloo were of defeat and disaster, which again reduced consols to a panic price. the rothschilds, notified of the victory a few hours sooner than the government itself, bought largely of securities which, in twenty-four hours, almost doubled in value. moses montefiore, sharing in these transactions, found himself at forty-five a millionaire. instead of slaving away in business to the end of his life, adding million to million, with the risk of losing all at last, he took the wise resolution of retiring from business and devoting the rest of his life to works of philanthropy. when queen victoria came to the throne in , moses montefiore was sheriff of london. the queen had lived near his country-house, and had often as a little girl strolled about his park. she now enjoyed the satisfaction of conferring upon her neighbor the honor of knighthood, and a few years later she made him a baronet. thus he became sir moses, which has an odd sound to us, but which in england seems natural enough. during the last fifty years sir moses has been, as it were, a professional philanthropist. every good cause has shared his bounty, but he has been most generous to poor members of his own race and religion. he has visited seven times the holy land, where the jews have been for ages impoverished and degraded. he has directed his particular attention to improving the agriculture of palestine, once so fertile and productive, and inducing the jews to return to the cultivation of the soil. in that country he himself caused to be planted an immense garden, in which there are nine hundred fruit trees, made productive by irrigation. he has promoted the system of irrigation by building aqueducts, digging wells, and providing improved apparatus. he has also endowed hospitals and almshouses in that country. in whatever part of the world, during the last fifty years, the jews have been persecuted or distressed, he has put forth the most efficient exertions for their relief, often going himself to distant countries to convey the requisite assistance. when he was ninety-one years of age he went to palestine upon an errand of benevolence. he has pleaded the cause of his persecuted brethren before the emperor of russia, and pleaded it with success. to all that part of the world known to us chiefly through the jews he has been a constant and most munificent benefactor during the last half century, while never turning a deaf ear to the cry of want nearer home. in october he completes his hundredth year. at present (january, ), he reads without spectacles, hears well, stands nearly erect, although six feet three in height, and has nothing of the somnolence of old age. he drives out every day, gets up at eleven, and goes to bed at nine. his diet is chiefly milk and old port wine, with occasionally a little soup or bread and butter. he still enjoys the delights of beneficence, which are among the keenest known to mortals, and pleases himself this year by giving checks of ninety-nine pounds to benevolent objects, a pound for each year that he has had the happiness of living. marquis of worcester, inventor of the steam-engine. in the english county of monmouthshire, near wales, a region of coal mines and iron works, there are the ruins of raglan castle, about a mile from a village of the same name. to these ruins let pilgrims repair who delight to visit places where great things began; for here once dwelt the marquis of worcester, who first made steam work for men. the same family still owns the site; as indeed it does the greater part of the county; the head of the family being now styled the duke of beaufort. the late lord raglan, commander of the english forces in the crimea, belonged to this house, and showed excellent taste in selecting for his title a name so interesting. perhaps, however, he never thought of the old tower of raglan castle, which is still marked and indented where the second marquis of worcester set up his steam-engine two hundred and twenty years ago. very likely he had in mind the time when the first marquis held the castle for charles i. against the roundheads, and baffled them for two months, though he was then eighty-five years of age. it was the son of that valiant and tough old warrior who put steam into harness, and defaced his ancestral tower with a ponderous and imperfect engine. for many centuries before his time something had been known of the power of steam; and the egyptians, a century or more before christ, had even made certain steam toys, which we find described in a manuscript written about b. c., at alexandria, by a learned compiler and inventor named hero. one of these was in the form of a man pouring from a cup a libation to the gods. the figure stood upon an altar, and it was connected by a pipe with a kettle of water underneath. on lighting a fire under the kettle, the water was forced up through the figure, and flowed out of the cup upon the altar. another toy was a revolving copper globe, which was kept in motion by _the escape_ of steam from two little pipes bent in the same direction. of this contrivance the french professor arago once wrote:-- "this was, beyond doubt, a machine in which steam engendered motion, and could produce mechanical effects. it was _a veritable steam-engine_! let us hasten, however, to add that it bears no resemblance, either by its form or in mode of action, to steam-engines now in use." other steam devices are described by hero. by one a horn was blown, and by another figures were made to dance upon an altar. but there is no trace in the ancient world of the application of steam to an important useful purpose. professor thurston of hoboken, in his excellent work upon the "history of the steam-engine," has gleaned from the literature of the last seven hundred years several interesting allusions to the nature and power of steam. in there was, it appears, at rheims in france, some sort of contrivance for blowing a church organ by the aid of steam. there is an allusion, also, in a french sermon of , to the awful power in volcanic eruptions of a small quantity of confined steam. there are traces of steam being made to turn a spit upon which meat was roasted. an early french writer mentions the experiment of exploding a bomb-shell nearly filled with water by putting it into a fire. in king charles the first of england granted to david ramseye a patent for nine different contrivances, among which were the following:-- "to raise water from low pits by fire. to make any sort of mills to go on standing waters by continual motion without help of wind, water, or horse. to make boats, ships, and barges to go against strong wind and tide. to raise water from mines and coal pits by a way never yet in use." this was in , which was about the date of the marquis of worcester's engine. it is possible, however, that these devices existed only in the imagination of the inventor. the marquis was then twenty-nine years of age, and as he was curious in matters of science, it is highly probable that he was acquainted with this patent, and may have conversed with the inventor. it is strange how little we know of a man so important as the marquis of worcester in our modern industrial development. i believe that not one of the histories of england mentions him, and scarcely anything is known of the circumstances that led to his experimenting with steam. living in a county of coal and iron mines, and his own property consisting very much in coal lands, his attention must of necessity have been called to the difficulties experienced by the miners in pumping the water from the deep mines. there were mines which employed as many as five hundred horses in pumping out the water, and it was a thing of frequent occurrence for a productive mine to be abandoned because the whole revenue was absorbed in clearing it of water. this inventor was perhaps the man in england who had the greatest interest in the contrivance to which in early life he turned his mind. he was born in the year , and sprung from a family whose title of nobility dated back to the fourteenth century. he is described by his english biographer as a learned, thoughtful, and studious roman catholic; as public-spirited and humane; as a mechanic, patient, skillful, full of resources, and quick to comprehend. he inherited a great estate, not perhaps so very productive in money, but of enormous intrinsic value. there is reason to believe that he began to experiment with steam soon after he came of age. he describes one of his experiments, probably of early date:-- "i have taken a piece of a whole cannon, whereof the end was burst, and filled it with water three quarters full, stopping and screwing up the broken end, as also the touch-hole, and making a constant fire under it. within twenty-four hours it burst, and made a great crack." that the engine which he constructed was designed to pump water is shown by the very name which he gave it,--"the water-commanding engine,"--and, indeed, it was never used for any other purpose. the plan of it was very simple, and, without improvements, it could have answered its purposes but imperfectly. it consisted of two vessels from which the air was driven alternately by the condensation of steam within them, and into the vacuum thus created the water rushed from the bottom of the mine. he probably had his first machine erected before , when he was still a young man, and he spent his life in endeavors to bring his invention into use. in doing this he expended so large a portion of his fortune, and excited so much ridicule, that he died comparatively poor and friendless. i think it probable, however, that his poverty was due rather to the civil wars, in which his heroic old father and himself were so unfortunate as to be on the losing side. he attempted to form a company for the introduction of his machine, and when he died without having succeeded in this, his widow still persisted in the same object, though without success. he did, however, make several steam-engines besides the one at raglan castle; engines which did actually answer the purpose of raising water from considerable depths in a continuous stream. he also erected near london a steam fountain, which he describes. during the next century several important improvements were made in the steam-engine, but without rendering it anything like the useful agent which we now possess. when james watt began to experiment, about the year , in his little shop near the glasgow university, the steam-engine was still used only for pumping water, and he soon discovered that it wasted three fourths of the steam. he once related to a friend how the idea of his great improvement, that of saving the waste by a condenser, occurred to his mind. he was then a poor mechanic living upon fourteen shillings a week. "i had gone to take a walk," he said, "on a fine sabbath afternoon. i had entered the green by the gate at the foot of charlotte street, and had passed the old washing-house. i was thinking upon the engine at the time, and had gone as far as the herd's house, when the idea came into my mind that, as steam was an elastic body, it would rush into a vacuum, and, if a communication were made between the cylinder and an exhausted vessel, it would rush into it, and might be there condensed without cooling the cylinder." he had found it! before he had crossed the green, he added, "the whole thing was arranged in my mind." since that memorable day the invention has been ever growing; for, as professor thurston well remarks: "great inventions are never the work of any one mind." from hero to corliss is a stretch of nearly twenty centuries; during which, probably, a thousand inventive minds have contributed to make the steam-engine the exquisite thing it is to-day. an old dry-goods merchant's recollections. our great cities have a new wonder of late years. i mean those immense dry-goods stores which we see in paris, london, new york, vienna, boston, cincinnati, chicago, in which are displayed under one roof almost all the things worn, or used for domestic purposes, by man, woman, or child. what a splendid and cheering spectacle the interior presents on a fine, bright day! the counters a tossing sea of brilliant fabrics; crowds of ladies moving in all directions; the clerks, well-dressed and polite, exhibiting their goods; the cash-boys flying about with money in one hand and a bundle in the other; customers streaming in at every door; and customers passing out, with the satisfied air of people who have got what they want. it gives the visitor a cheerful idea of abundance to see such a provision of comfortable and pleasant things brought from every quarter of the globe. an old dry-goods merchant of london, now nearly ninety, and long ago retired from business with a large fortune, has given his recollections of business in the good old times. there is a periodical, called the "draper's magazine," devoted to the dry-goods business, and it is in this that some months ago he told his story. when he was a few months past thirteen, being stout and large for his age, he was placed in a london dry-goods store, as boy of all work. no wages were given him. at that time the clerks in stores usually boarded with their employer. on the first night of his service, when it was time to go to bed, he was shown a low, truckle bedstead, under the counter, made to pull out and push in. he did not have even this poor bed to himself, but shared it with another boy in the store. on getting up in the morning, instead of washing and dressing for the day, he was obliged to put on some old clothes, take down the shutters of the store,--which were so heavy he could hardly carry them,--then clean the brass signs and the outside of the shop windows, leaving the inside to be washed by the older clerks. when he had done this, he was allowed to go up stairs, wash himself, dress for the day, and to eat his breakfast. then he took his place behind the counter. we think it wrong for boys under fourteen to work ten hours a day. but in the stores of the olden time, both boys and men worked from fourteen to sixteen hours a day, and nothing was thought of it. this store, for example, was opened soon after eight in the morning, and the shutters were not put up till ten in the evening. there was much work to do after the store was closed; and the young men, in fact, were usually released from labor about a _quarter past eleven_. on saturday nights the store closed at twelve o'clock, and it was not uncommon for the young men to be employed in putting away the goods until between two and three on sunday morning. "there used to be," the old gentleman records, "a supper of hot beafsteaks and onions, and porter, which we boys used to relish immensely, and eat and drink a good deal more of both than was good for us." after such a week's work one would think the clerks would have required rest on sunday. but they did not get much. the store was open from eight until church time, which was then eleven o'clock; and this was one of the most profitable mornings of the week. the old gentleman explains why it was so. almost all factories, shops, and stores were then kept open very late, and the last thing done in them was to pay wages, which was seldom accomplished until after midnight. hence the apparent necessity for the sunday morning's business. another great evil mentioned by our chronicler grew out of this bad system of all work and no play. the clerks, released from business towards midnight, were accustomed to go to a tavern and spend part of the night in drinking and carousing; reeling home at a late hour, much the worse for drink, and unfit for business in the morning until they had taken another glass. all day the clerks were in the habit of slipping out without their hats to the nearest tap-room for beer. nor was the system very different in new york. an aged book-keeper, to whom i gave an outline of the old gentleman's narrative, informs me that forty years ago the clerks, as a rule, were detained till very late in the evening, and often went from the store straight to a drinking-house. now let us see how it fared with the public who depended upon these stores for their dry-goods. from our old gentleman's account it would seem that every transaction was a sort of battle between the buyer and seller to see which should cheat the other. on the first day of his attendance he witnessed a specimen of the mode in which a dexterous clerk could sell an article to a lady which she did not want. an unskillful clerk had displayed too suddenly the entire stock of the goods of which she was in search; upon which she rose to leave, saying that there was nothing she liked. a more experienced salesman then stepped up. "walk this way, madam, if you please, and i will show you something entirely different, with which i am sure you will be quite delighted." he took her to the other end of the store, and then going back to the pile which she had just rejected, snatched up several pieces, and sold her one of them almost immediately. customers, the old merchant says, were often bullied into buying things they did not want. "many a half-frightened girl," he remarks, "have i seen go out of the shop, the tears welling up into her eyes, and saying, 'i am sure i shall never like it:' some shawl or dress having been forced upon her contrary to her taste or judgment." the new clerk, although by nature a very honest young fellow, soon became expert in all the tricks of the trade. it was the custom then for employers to allow clerks a reward for selling things that were particularly unsalable, or which required some special skill or impudence in the seller. for example, they kept on hand a great supply of what they were pleased to call "remnants," which were supposed to be sold very cheap; and as the public of that day had a passion for remnants, the master of the shop took care to have them made in sufficient numbers. there were heaps of remnants of linen, and it so _happened_ that the remnants were exactly long enough for a shirt, or some other garment. any clerk who could push off one of these remnants upon a customer was allowed a penny or twopence as a reward for his talent; and there were certain costly articles, such as shawls and silks of unsalable patterns, upon which there was a premium of several shillings for selling. there was one frightfully ugly shawl which had hung fire so long that the master of the shop offered a reward of eight shillings (two dollars) to any one who should sell it at the full price; which was twenty dollars. our lad covered himself with glory one morning, by selling this horrid old thing. a sailor came in to buy a satin scarf for a present. the boy saw his chance. "as you want something for a present," said he to the sailor, "would you not like to give something really useful and valuable that would last for years?" in three minutes the sailor was walking out of the store, happy enough, with the shawl under his arm, and the sharp youth was depositing the price thereof in the money-drawer. very soon he had an opportunity of assisting to gull the public on a great scale. his employer bought out the stock of an old-fashioned dry-goods store in another part of the town for a small sum; upon which he determined to have a grand "selling off." to this end he filled the old shop with all his old, faded, unsalable goods, besides looking around among the wholesale houses and picking up several cart-loads of cheap lots, more or less damaged. the whole town was flooded with bills announcing this selling off of the old established store, at which many goods could be obtained at less than half the original cost. as this was then a comparatively new trick the public were deceived by it, and it had the most astonishing success. the selling off lasted several weeks, the supply of goods being kept up by daily purchases. our junior clerk was an apt learner in deception and trickery. shortly after this experiment upon the public credulity, a careless boy lighting the lamps in the window (for this was before the introduction of gas) set some netting on fire, causing a damage of a few shillings, the fire being almost instantly extinguished. as business had been a little dull, the junior clerk conceived the idea of turning the conflagration to account. going up to his employer, and pointing to the singed articles, he said to him:-- "why not have a selling off here, and clear out all the stock damaged by fire?" the master laughed at the enormity of the joke, but instantly adopted the suggestion, and in the course of a day or two, flaming posters announced the awful disaster and the sale. in preparing for this event, the clerks applied lighted paper to the edges of whole stacks of goods, slightly discolored the tops of stockings, and in fact, they singed to such an extent as almost to cause a real conflagration. during these night operations a great deal of beer was consumed, and the whole effect of the manoeuvre was injurious and demoralizing to every clerk in the store. this sale also was ridiculously successful. a mob surrounded the doors before they were opened, and to keep up the excitement some low-priced goods were ostentatiously sold much below cost. such was the rush of customers that at noon the young men were exhausted by the labor of selling; the counters were a mere litter of tumbled dry-goods; and the shop had to be closed for a while for rest and putting things in order. to keep up the excitement, the master and his favorite junior clerk rode about london in hackney coaches, in search of any cheap lots that would answer their purpose. in the course of time, this clerk, who was at heart an honest, well-principled fellow, grew ashamed of all this trickery and fraud, and when at length he set up in business for himself, he adopted the principle of "one price and no abatement." he dealt honorably with all his customers, and thus founded one of the great dry-goods houses of london. two things saved him: first, he loathed drinking and debauchery; secondly, he was in the habit of reading. the building up of the huge establishments, to which some persons object, has nearly put an end to the old system of guzzling, cheating, and lying. the clerks in these great stores go to business at eight o'clock in the morning, and leave at six in the evening, with an interval for dinner. they work all day in a clean and pleasant place, and they are neither required or allowed to lie or cheat. a very large establishment must be conducted honestly, or it cannot long go on. its very largeness _compels_ an adherence to truth and fact. proofreading team at www.pgdp.net [illustration] scientific american supplement no. new york, january , . scientific american supplement. vol. xiii., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. page i. engineering and mechanics.--watchman's detecter. integrating apparatus. a canal boat propelled by air. head linings of passenger cars. improved mortar mixer. figures. practical notes on plumbing. by j.p. davies. figs. to . tinning iron pipes, copper or brass work, bits, etc.--spirit brush.--soldering iron to lead.--dummies for pipe bending.--bends and set-offs.--bending with water. --sand bending.--bending with balls or bobbins.--three-ball or lead driving ball and double ball bending.--bending with windlass and brass ball.--hydraulic or cup leather and ball bending.--bending by splitting, or split made bends. --pulling up bends.--set-offs.--bad bends.--bad falls in bends.--bends made into traps or retarders.--bends made with the "snarling dummy." the grossenhain shuttle driver. figure. ii. electricity, magnetism, etc.--the electro-magnetic apparatus of dr. pacinotti. figures. the pacinotti electro-magnetic machine of .--the elias electro-motor of . the elias electro-motor. bjerknes's experiments. figures. the arc electric light. by leo daft. hedges' electric lamps. figures. electric railway apparatus at the paris electrical exhibition. figures. lartigue's switch controller, elevation and sections.--position of commutators during the maneuver.--pedal for sending warning to railway crossing, with elevation and end and plan views.--electric alarm.--lartigue's bellows pedal, with plan and sections.--brunot's controller.--guggemos' correspondence apparatus.--annunciator apparatus.--lartigue's controller for water tanks.--vérité controller for water tanks. the telephonic halls of the electrical exhibition. figure. the action of cold on the voltaic arc. iii. technology and chemistry.--industrial art for women. photography upon canvas. figure. detection of starch sugar sirup mixed with sugar house molasses. false vermilion. the position of manganese in modern industry.--by m.v. deshaeys. ferro-manganese.--cupro-manganese.-- manganese bronzes.--metallic manganese.--manganese german silver.--phosphorus bronze. the economical washing of coal gas and smoke.--m. chevalet's method. determination of nitrogen in hair, wool, dried blood, flesh meal, and leather scraps. by dr. c. krauch. testing white beeswax for ceresine and paraffine. by a. peltz. the prevention of alcoholic fermentation by fungi. by prof. e. reichard. new reaction of glycerine. lycopodine. conchinamine. chinoline. preparation of coniine. strontianite. iv. miscellaneous.--household and other recipes. christmas plum pudding.--plum pudding sauce.-- national plum pudding and sauce.--egg nog.--egg flip.--roast turkey.--woodcock and snipe.--canvas-back duck.--pheasants.--wild ducks.--wild fowl sauce.--brown fricassee of rabbits.--orange pudding. --venison pastry.--christmas red round.--plum porridge.--sugared pears.--table beer.--mince meat. --pumpkin pie.--brandy punch.--boeuf a la mode.-- punch jelly.--orange salad.--cranberry jelly.--plum cake.--black cake.--potatoes. the bayeux tapestry comet. synthetic experiments on the artificial reproduction of meteorites. v. hygiene and medicine.--parangi; a newly described disease. a castor oil substitute. lack of sun light. * * * * * the electro-magnetic apparatus of dr. pacinotti. in admiring the recent developments of electric science as evidenced by the number of important inventions which have during the past few years been given to the world, especially in those branches of applied science which deal more particularly with the generation of electricity and the production of the electric light, there is often too great a tendency to forget, or, at least, to pass over in comparative silence the claims which the great pioneer workers and discoverers undoubtedly have to a large share of the merit of this scientific development. it is, of course, obviously impossible in anything approaching a retrospect of the science of magneto-electric induction or its application to illumination to pass slightly over the names of oersted, of ampère, of davy, and of faraday, but, in other respects, their work is too often lost sight of in the splendid modern developments of their discoveries. again, there is another group of discoverer-inventors who occupy an intermediate position between the abstract discoverers above named and the inventors and adapters of still more recent times. to this group belong the names of pixii and saxton, holmes and nollet, wilde, varley, siemens, wheatstone, and pacinotti, who was the first to discover a means of constructing a machine capable of giving a continuous current always in the same direction, and which has since proved itself to be the type of nearly all the direct current electric machines of the present day, and especially those such as the gramme and brush and de meritens machines, in which the rotating armature is of annular form; and when it is considered what a large number of the well known electric generators are founded upon this discovery, it must be a matter of general gratification that the recent international jury of the paris exhibition of electricity awarded to dr. antonio pacinotti one of their highest awards. the original machine designed by dr. pacinotti in the year , and which we illustrate on the present page, formed one of the most interesting exhibits in the paris exhibition, and conferred upon the italian section a very distinctive feature, and we cannot but think that while all were interested in examining it, there must have been many who could not help being impressed with the fact that it took something away from the originality of design in several of the machines exhibited in various parts of the building. this very interesting machine was first illustrated and described by its inventor in the _nuovo cimento_ in the year , under the title "a description of a small electro-magnetic machine," and to this description we are indebted for the information and diagrams contained in this notice, but the perspective view is taken from the instrument itself in the paris exhibition. in this very interesting historical communication the author commences by describing a new form of electro-magnet, consisting of an iron ring around which is wound (as in the gramme machine) a single helix of insulated copper wire completely covering the ring, and the two ends of the annular helix being soldered together, an annular magnet is produced, enveloped in an insulated helix forming a closed circuit, the convolutions of which are all in the same direction. if in such a system any two points of the coil situated at opposite ends of the same diameter of the ring be connected respectively with the two poles of a voltaic battery, the electric current having two courses open to it, will divide into two portions traversing the coil around each half of the ring from one point of contact to the other, and the direction of the current, in each portion will be such as to magnetize the iron core, so that its magnetic poles will be situated at the points where the current enters and leaves the helix, and a straight line joining these points may be looked upon as the magnetic axis of the system. from this construction it is clear that, by varying the position of the points of contact of the battery wires and the coil, the position of the magnetic axis will be changed accordingly, and can be made to take up any diametrical position with respect to the ring, of which the two halves (separated by the diameter joining the points of contact of the battery wires with the coil) may be regarded as made up of two semicircular horseshoe electro-magnets having their similar poles joined. to this form of instrument the name "transversal electro magnet" (_eletro calamita transversale_) was given by its inventor, to whom is undoubtedly due the merit of having been the first to construct an electro-magnet the position of whose poles could be varied at will by means of a circular commutator. [illustration: pacinotti electro-magnetic machine.--made in .] by applying the principle to an electro-magnetic engine, dr. pacinotti produced the machine which we illustrate on the present page. the armature consists of a turned ring of iron, having around its circumference sixteen teeth of equal size and at equal angular distance apart, as shown in fig. , forming between them as many spaces or notches, which are filled up by coiling within them helices of insulated copper wire, r r r, in a similar manner to that adopted in winding the brush armature, and between them are fixed as many wooden wedges, m m, by which the helices are firmly held in their place. all the coils are wound round the ring in the same direction, and the terminating end of each coil is connected to the commencing end of the next or succeeding helix, and the junctions so made are attached to conducting wires which are gathered together close to the vertical shaft on which the armature ring is fixed, passing through holes at equal distances apart in a wooden collar fixed to the same shaft, and being attached at their lower extremities to the metallic contact pieces of the commutator, c, shown at the lower part of fig. , which is an elevation of the machine, while fig. is a plan of the same apparatus. the commutator consists of a small boxwood cylinder, carrying around its cylindrical surface two rows of eight holes, one above the other, in which are fitted sixteen contact pieces of brass which slightly project above the surface of the wood, the positions of those in the upper circle alternating or "breaking joint" with those in the lower, and each contact piece is in metallic connection with its corresponding conducting wire, and, therefore, with the junction of two of the helices on the armature. against the edge of the commutator are pressed by means of adjustable levers two small brass contact rollers, k k, which are respectively connected with the positive and negative poles of the voltaic battery (either through or independent of the coils of a fixed electro-magnet, to which we shall presently refer), and the magnetic axis of the ring will lie in the same plane as the line joining the points of contact of the battery and rotating helix, this axis remaining nearly fixed notwithstanding the rotation of the iron ring in which the magnetism is induced. in the apparatus figured in figs. and , the armature rotates between the two vertical limbs, a b, of a fixed electro-magnet furnished with extended pole pieces, a a, b b (fig. ), each of which embraces about six of the armature coils. the fixed electro-magnet is constructed of two vertical iron cylindrical bars, a and b, united at their lower extremities by a horizontal iron bar, f f, the one being rigidly and permanently attached to it, while the other is fastened to it by a screw, g, passing through a slot so that the distance of the pole pieces from one another and from the armature ring is capable of adjustment. the connections of the machine, which are shown in fig. , are made as follows: the positive current, entering by the attachment screw, h, passes by a wire to the right hand commutator screw, l, to the right-hand roller, k, through the commutator to the ring, around which it traverses to the left-hand roller, k¹, and screw, l¹, to the magnet coil, a, and thence through the coil of the magnet, b, to the terminal screw, h, on the right hand of the figure. this method of coupling up is of very great historical interest, for it is the first instance on record of the magnet coils and armature of a machine being included in one circuit, giving to it the principle of construction of a dynamo-electric machine, and antedating in publication, by two years, the interesting machines of siemens, wheatstone, and varley, and preceding them in construction by a still longer period. with this apparatus dr. pacinotti made the following interesting experiments with the object of determining the amount of mechanical work produced by the machine (when worked as an electro-magnetic engine), and the corresponding consumption of the elements of the battery: attached to the spindle of the machine was a small pulley, q q (fig. ), for the purpose of driving, by means of a cord, another pulley on a horizontal spindle carrying a drum on which was wound a cord carrying a weight, and on the same spindle was also a brake and brake-wheel, the lever of which was loaded so as just to prevent the weight setting into motion the whole system, consisting of the two machines, when no current was flowing. in this condition, when the machine was set in motion by connecting the battery, the mechanical work expended in overcoming the friction of the brake was equal to that required to raise the weight; and, in order to obtain the total work done, all that was necessary was to multiply the weight lifted by the distance through which it was raised. the consumption of the battery was estimated at the same time by interposing in the circuit a sulphate of copper voltameter, of which the copper plate was weighed before and after the experiment. the following are some of the results obtained by dr. pacinotti in experimenting after the manner just described. with the current from a battery of four small bunsen elements, the machine raised a weight of . kilos to a height of . m. (allowing for friction), so that the mechanical work was represented by . m. during the experiment the positive plate of the voltameter lost in weight . gramme, the negative gaining . gramme, giving an average of chemical work performed in the voltameter of . gramme, and multiplying this figure by the ratio between the equivalent of zinc to that of copper, and by the number of the elements of the battery, the weight of zinc consumed in the battery was computed at . gramme, so that to produce one kilogrammeter of mechanical work milligrammes of zinc would be consumed in the battery. in another experiment, made with five elements, the consumption of zinc was found to be milligrammes for every kilogrammeter of mechanical work performed. in recording these experiments, dr. pacinotti points out that although these results do not show any special advantage in his machine over those of other construction, still they are very encouraging, when it is considered that the apparatus with which the experiments were made were full of defects of workmanship, the commutator, being eccentric to the axis, causing the contacts between it and the rollers to be very imperfect and unequal. in his communication to the _nuovo cimento_, dr. pacinotti states that the reasons which induced him to construct the apparatus on the principle which we have just described, were: ( ) that according to this system the electric current is continuously traversing the coils of the armature, and the machine is kept in motion not by a series of intermittent impulses succeeding one another with greater or less rapidity, but by a constantly acting force producing a more uniform effect. ( ) the annular form of the revolving armature contributes (together with the preceding method of continuous magnetization) to give regularity to its motion and at the same time reduces the loss of motive power, through mechanical shocks and friction, to a minimum. ( ) in the annular system no attempt is made suddenly to magnetize and demagnetize the iron core of the rotating armature, as such changes of magnetization would be retarded by the setting up of extra currents, and also by the permanent residual magnetism which cannot be entirely eliminated from the iron; and with this annular construction such charges are not required, all that is necessary being that each portion of the iron of the ring should pass, in its rotation, through the various degrees of magnetization in succession, being subjected thereby to the influence of the electro-dynamic forces by which its motion is produced. ( ) the polar extension pieces of the fixed electro-magnet, by embracing a sufficiently large number of the iron projecting pieces on the armature ring, continue to exercise an influence upon them almost up to the point at which their magnetization ceases when passing the neutral axis. ( ) by the method of construction adopted, sparks, while being increased in number, are diminished in intensity, there being no powerful extra currents produced at the breaking of the circuit, and dr. pacinotti points out that when the machine is in rotation a continuous current is induced in the circuit which is opposed to that of the battery; and this leads to what, looked at by the light of the present state of electric science, is by far the most interesting part of dr. pacinotti's paper, published, as it was, more than seventeen years ago. in the part to which we refer, dr. pacinotti states that it occurred to him that the value of the apparatus would be greatly increased if it could be altered from an electro-magnetic to a magneto-electric machine, so as to produce a continuous current. thus, if the electro-magnet, a b (figs. and ), be replaced by a permanent magnet, and the annular armature were made to revolve, the apparatus would become a magneto-electric generator, which would produce a continuous induced current always in the same direction, and in analyzing the action of such a machine dr. pacinotti observes that, as the position of the magnetic field is fixed, and the iron armature with its coils rotates within it, the action may be regarded as the same as if the iron ring were made up of two fixed semicircular horseshoe magnets with their similar poles joined, and the coils were loose upon it and were caused to rotate over it, and this mode of expressing the phenomenon was exactly what we adopted when describing the gramme machine, without having at that time seen what dr. pacinotti had written fifteen years before. in explanation of the physical phenomena involved in the induction of the electric currents in the armature when the machine is in action as a generator, dr. pacinotti makes the following remarks: let us trace the action of one of the coils in the various positions that it can assume in one complete revolution; starting from the position marked n, fig. , and moving toward s, an electric current will be developed in it in one direction while moving through the portion of the circle, n a, and after passing the point, a, and while passing through the arc, a s, the induced current will be in the opposite direction, which direction will be maintained until the point, b, is reached, after which the currents will be in the same direction as between n and a; and as all the coils are connected together, all the currents in a given direction will unite and give the combined current a direction indicated by the arrows in fig. , and in order to collect it (so as to transmit it into the external circuit), the most eminent position for the collectors will be at points on the commutator at opposite ends of a diameter which is perpendicular to the magnetic axis of the magnetic field. with reference to fig. , we imagine either that the two arrows to the right of the figure are incorrectly placed by the engraver, or that dr. pacinotti intended this diagram to express the direction of the current throughout the whole circuit, as if it started from a, and after traversing the external circuit entered again at b, thus completing the whole cycle made up of the external and internal circuits. dr. pacinotti calls attention to the fact that the direction of the current generated by the machine is reversed by a reversal of the direction of rotation, as well as by a shifting of the position of the collectors from one side to the other of their neutral point, and concludes his most interesting communication by describing experiments made with it in order to convert it into a magneto-electric machine. "i brought," he says, "near to the coiled armature the opposite poles of two permanent magnets, and i also excited by the current from a battery the fixed electro-magnets (see figs. and ), and by mechanical means i rotated the annular armature on its axis. by both methods i obtained an induced electric current, which was continuous and always in the same direction, and which, as was indicated by a galvanometer, proved to be of considerable intensity, although it had traversed the sulphate of copper voltameter which was included in the circuit." dr. pacinotti goes on to show that there would be an obvious advantage in constructing electric generating machines upon this principle, for by such a system electric currents can be produced which are continuous and in one direction without the necessity of the inconvenient and more or less inefficient mechanical arrangements for commutating the currents and sorting them, so as to collect and combine those in one direction, separating them from those which are in the opposite; and he also points our the reversibility of the apparatus, showing that as an electro-magnetic engine it is capable of converting a current of electricity into mechanical motion capable of performing work, while as a magneto-electric machine it is made to transform mechanical energy into an electric current, which in other apparatus, forming part of its external circuit, is capable of performing electric, chemical, or mechanical work. all these statements are matters of everyday familiarity at the present day, but it must be remembered that they are records of experiments made twenty years ago, and as such they entitle their author to a very distinguished place among the pioneers of electric science, and it is somewhat remarkable that they did not lead him straight to the discovery of the "action and reaction" principle of dynamo-electric magnetic induction to which he approached so closely, and it is also a curious fact that so suggestive and remarkable a paper should have been written and published as far back as , and that it should not have produced sooner than it did a revolution in electric science.--_engineering._ * * * * * the elias electromotor. we lately published a short description of a very interesting apparatus which may be considered in some sense as a prototype of the gramme machine, although it has very considerable, indeed radical differences, and which, moreover, was constructed for a different purpose, the elias machine being, in fact, an electromotor, while the gramme machine is, it is almost unnecessary to say, an electric generator. this apparent resemblance makes it, however, necessary to describe the elias machine, and to explain the difference between it and the gramme. its very early date ( ), moreover, gives it an exceptional interest. the figures on the previous page convey an exact idea of the model that was exhibited at the paris electrical exhibition, and which was contributed by the ecole polytechnique of delft in the dutch section. this model is almost identical with that illustrated and described in a pamphlet accompanying the exhibit. the perspective illustrations show the machine very clearly, and the section explains the construction still further. the apparatus consists of an exterior ring made of iron, about in. in diameter and . in wide. it is divided into six equal sections by six small blocks which project from the inner face of the ring, and which act as so many magnetic poles. on each of the sections between the blocks is rolled a coil, of one thickness only, of copper wire about . in. in diameter, inclosed in an insulating casing of gutta percha, giving to the conductor thus protected a total thickness of . in.; this wire is coiled, as shown in the illustration. it forms twenty-nine turns in each section, and the direction of winding changes at each passage in front of a pole piece. the ends of the wire coinciding with the horizontal diameter of the ring are stripped of the gutta percha, and are connected to copper wires which are twisted together and around two copper rods, which are placed vertically, their lower ends entering two small cavities made in the base of the apparatus. the circuit is thus continuous with two ends at opposite points of the same diameter. the ring is about . in. thick, and is fixed, as shown, to two wooden columns, b b, by two blocks of copper, a. [illustration: the elias electromotor.--made in .] it will be seen from the mode of coiling the wire on this ring, that if a battery be connected by means of the copper rods, the current will create six consecutive poles on the various projecting blocks. the inner ring, e, is about in. in outside diameter, and is also provided with a series of six projecting pieces which pass before those on the exterior ring with very little clearance. between these projections the space between the inner face of the outer, and the outer face of the inner ring, is . in. the latter is movable, and is supported by three wooden arms, f, fixed to a boss, g, which is traversed by a spindle supported in bearings by the columns, a and c. a coil is rolled around the ring in exactly the same way as that on the outer ring, the wire being of the same size, and the insulation of the same thickness. the ends of the wire are also bared at points of the diameter opposite each other, and the coil connected in pairs so as to form a continuous circuit. at the two points of junction they are connected with a hexagonal commutator placed on the central spindle, one end corresponding to the sides , , and , and the other to the sides , , and . two copper rods, j, fixed on the base to two plates of copper furnished with binding screws, are widened and flattened at their upper ends to rest against opposite parallel sides of the hexagon. it will be seen that if the battery is put in circuit by means of the binding screws, the current in the interior ring will determine six consecutive poles, the names of which will change as the commutator plates come into contact successively with the sides of the hexagon. consequently, if at first the pole-pieces opposite each other are magnetized with the same polarity, a repulsion between them will be set up which will set the inner ring in motion, and the effect will be increased on account of the attraction of the next pole of the outer ring. at the moment when the pole piece thus attracted comes into the field of the pole of opposite polarity, the action of the commutator will change its magnetization, while that of the pole-piece on the fixed ring always remains the same; the same phenomenon of repulsion will be produced, and the inner ring will continue its movement in the same direction, and so on. to the attractive and repulsive action of the magnetic poles has to be added the reciprocal action of the coils around the two rings, the action of which is similar. from this brief explanation the differences between the elias machine and the gramme will be understood. the dutch physicist did not contemplate the production of a current; he utilized two distinct sources of electricity to set the inner ring in motion, and did not imagine that it was possible, by suppressing one of the inducing currents and putting the ring in rapid rotation, to obtain a continuous current. moreover, if ever this apparent resemblance had been real, the merit of the gramme invention would not have been affected by it. it has happened very many times that inventors living in different countries, and strangers to one another, have been inspired with the same idea, and have followed it by similar methods, either simultaneously or at different periods, without the application having led to the same results. it does not suffice even for the seed to be the same; it must have fallen in good ground, and be cultivated with care; here it scarcely germinates, there it produces a vigorous plant and abundant fruit.--_engineering._ * * * * * bjerknes's experiments. as a general thing, too much trust should not be placed in words. in the first place, it frequently happens that their sense is not well defined, or that they are not understood exactly in the same way by everybody, and this leads to sad misunderstandings. but even in case they are precise, and are received everywhere under a single acceptation, there still remains one danger, and that is that of passing from the word to the idea, and of being led to believe that, because there is a word, there is a real thing designated by this word. let us take, for example, the word _electricity_. if we understand by this term the common law which embraces a certain category of phenomena, it expresses a clear and useful idea; but as for its existence, it is not permitted to believe _a priori_ that there is a distinct agent called electricity which is the efficient cause of the phenomena. we ought never, says the old rule of philosophy, to admit entities without an absolute necessity. the march of science has always consisted in gradually eliminating these provisory conceptions and in reducing the number of causes. this fact is visible without going back to the ages of ignorance, when every new phenomenon brought with it the conception of a special being which caused it and directed it. in later ages they had _spirits_ in which there was everything: volatile liquids, gases, and theoretical conceptions, such as phlogiston. at the end of the last century, and at the beginning of our own, ideas being more rational, the notion of the "fluid" had been admitted, a mysterious and still vague enough category (but yet an already somewhat definite one) in which were ranged the unknown and ungraspable causes of caloric, luminous, electric, etc., phenomena. gradually, the "fluid" has vanished, and we are left (or rather, we were a short time ago) at the notion of forces--a precise and mathematically graspable notion, but yet an essentially mysterious one. we see this conception gradually disappearing to leave finally only the elementary ideas of matter and motion--ideas, perhaps, which are not much clearer philosophically than the others, particularly that of matter taken _per se_, but which, at least, are necessary, since all the others supposed them. among those notions that study and time are reducing to other and simpler ones, that of electricity should be admitted; for it presents itself more and more as one of the peculiar cases of the general motion of matter. it will be to the eternal honor of fresnel for having introduced into science and mathematically constituted the theory of undulations (already proposed before him, however), thus giving the first example of the notion of motion substituted for that of force. since the principle of the conservation of energy has taken the eminent place in science that it now occupies, and we have seen a continual transformation of one series of phenomena into another, the mind is at once directed to the aspect of a new fact toward an explanation of this kind. still, it is certain that these hypotheses are difficult of justification; for those motions that are at present named molecular, and that we cannot help presuming to be at the base of all actions, are _per se_ ungraspable and can only be demonstrated by the coincidence of a large number of results. there is, however, another means of rendering them probable, and that is by employing analogy. if, by vibrations which are directly ascertainable, we can reproduce the effects of electricity, there will be good reason for admitting that the latter is nothing else than a system of vibration differing only, perhaps, in special qualities, such as dimensions, direction, rapidity, etc. such is the result that is attained by the very curious experiments that are due to mr. bjerknes. these constitute an _ensemble_ of very striking results, which are perfectly concordant and exhibit very close analogies with electrical effects, as we shall presently see. [illustration: fig. .] they are based on the presence of bodies set in vibration in a liquid. the vibrations produced by mr. bjerknes are of two kinds--pulsations and oscillations. the former of these are obtained by the aid of small drums with flexible ends, as shown to the left in fig. . a small pump chamber or cylinder is, by means of a tube, put in communication with one of these closed drums in which the rapid motion of a piston alternately sucks in and expels the air. the two flexible ends are successively thrust outward and attracted toward the center. in an apparatus of this kind the two ends repulse and attract the liquid at the same time. their motions are of the same phase; if it were desired that one should repulse while the other was attracting, it would be necessary to place two drums back to back, separated by a stiff partition, and put them in connection with two distinct pump chambers whose movements were so arranged that one should be forcing in while the other was exhausting. a system of this nature is shown to the right in fig. . the vibrations are obtained by the aid of small metal spheres fixed in tubular supports by movable levers to which are communicated the motions of compression and dilatation of the air in the pump chamber. they oscillate in a plane whose direction may be varied according to the arrangement of the sphere, as seen in the two apparatus of this kind shown in fig. . fig. will give an idea of the general arrangement. the two pistons of the air-pumps are connected to cranks that may be fixed in such a way as to regulate the phases as may be desired, either in coincidence or opposition. the entire affair is put in motion by a wheel and cord permitting of rapid vibrations being obtained. the air is let into the apparatus by rubber tubing without interfering with their motions. [illustration: fig. .] we may now enter into the details of the experiments: the first is represented in fig. . in a basin of water there is placed a small frame carrying a drum fixed on an axle and capable of revolving. it also communicates with one of the air cylinders. the operator holds in his hand a second drum which communicates with the other cylinder. the pistons are adjusted in such a way that they shall move parallel with each other; then the ends of the drums inflate and collapse at the same time; the _motions are of the same phase_; but if the drums are brought near each other a very marked attraction occurs, the revolving drum follows the other. if the cranks are so adjusted that the pistons move in an opposite direction, the _phases are discordant_--there is a repulsion, and the movable drum moves away from the other. the effect, then, is analogous to that of two magnets, with about this difference, that here it is the like phases that attract and the different phases that repel each other, while in magnets like poles repel and unlike poles attract each other. it is necessary to remark that it is indifferent which face of the drum is presented, since both possess the same phase. the drum behaves, then, like an insulated pole of a magnet, or, better, like a magnet having in its middle a succeeding point. in order to have two poles a double drum must be employed. the experiment then becomes more complicated; for it is necessary to have two pump chambers with opposite phases for this drum alone, and one or two others for the revolving drum. the effects, as we shall see, are more easily shown with the vibrating spheres. this form has the advantage that the vibrating body exhibits the two phases at the same time; relatively to the liquid, one of its ends advances while the other recedes. thus with a vibrating sphere presented to the movable drum, there may be obtained repulsion or attraction, according as the side which is approached is concordant or discordant with the end of the drum that it faces. [illustration: fig. .] with the arrangement shown in fig. there may be performed an interesting series of experiments. the two spheres supported by the frame are set in simultaneous vibration, and the frame, moreover, is free to revolve about its axis. the effect is analogous to that which would be produced by two short magnets carried by the same revolving support; on presenting the vibrating sphere to the extremities the whole affair is attracted or repulsed, according to its phase and according to the point at which it is presented; on replacing the transverse support by a single sphere (as indicated in the figure by a dotted line) we obtain the analogue of a short magnet carried on a pivot like a small compass needle. this sphere follows the pole of a vibrating sphere which is presented to it, as the pole of a magnet would do, with this difference always, that in the magnet, like poles repel, while in oscillating bodies like phases attract. in all the preceding experiments the bodies brought in presence were both in motion and the phenomena were analogous to those of permanent magnetism. we may also reproduce those which result from magnetism by induction. for this purpose we employ small balls of different materials suspended from floats, as shown in fig. (a, b, c). let us, for example, take the body, b, which is a small metal sphere, and present to it either a drum which is caused to pulsate, on an oscillating sphere, and it will be attracted, thus representing the action of a magnet upon a bit of soft iron. a curious experiment may serve to indicate the transition between this new series and the preceding. if we present to each other two drums of opposite phases, but so arranged that one of them vibrates faster than the other, we shall find, on carefully bringing them together, that the repulsion which manifested itself at first is changing to attraction. on approaching each other the drum having the quicker motion finally has upon the other, the same action as if the latter were immovable; and the effect is analogous to that which takes place between a strong and weak magnet presented by their like poles. [illustration: fig. .] by continuing these experiments we arrive at a very important point. instead of the body, b (fig. ), let us take c. as the figure shows, this is a sphere lighter than water, kept in the liquid by a weight. if we present to it the vibrating body, it will be repelled, and we shall obtain the results known by the name of diamagnetism. this curious experiment renders evident the influence of media. as well known, faraday attributed such effects to the action of the air; and he thought that magnetic motions always resulted from a difference between the attraction exerted by the magnet upon the body under experiment, and the attraction exerted by the air. if the body is more sensitive than the air, there is direct magnetism, but if it is less so, there is diamagnetism. water between the bodies, in the bjerknes experiments, plays the same role; it is this which, by its vibration, transmits the motions and determines the phases in the suspended body. if the body is heavier than water its motion is less than that of the liquid, and, consequently, relatively to the vibrating body, it is of like phase; and if it is lighter, the contrary takes place, and the phases are in discordance. these effects may be very well verified by the aid of the little apparatus shown in fig. , and which carries two bars, one of them lighter and the other heavier than water. on presenting to them the vibrating body, one presents its extremity and takes an axial direction, while the other arranges itself crosswise and takes the equatorial direction. these experiments may be varied in different ways that it is scarcely necessary to dwell upon in this place, as they may be seen at the electrical exhibition. [illustration: fig. .] very curious effects are also obtained with the arrangement shown in fig. . between the two drums there is introduced a body sustained by a float such as represented at a, fig. . various results may, then, be obtained according to the combinations adopted. let us suppose that the phases are alike, and that the interposed body is heavier than water; in this case it is repelled as far as the circumference of the drums, at which point it stops. if the phases are different, the influenced body behaves in the opposite manner and stops at the center. if the body is lighter than water the effects are naturally changed. placed between two like phases, it is attracted within a certain radius and repelled when it is placed further off; if the phases are unlike, it is always repelled. we may easily assure ourselves that these effects are analogous to those which are produced on bodies placed between the poles of wide and powerful magnets. it is useless to repeat that the analogies are always inverse. [illustration: fig. .] mr. bjerknes has carried the examination of these phenomena still further in studying experimentally the actions that occur in the depths of the liquid; and for this purpose he has made use of the arrangement shown in fig. . by the side of the vibrating body there is placed a light body mounted on a very flexible spring. this assumes the motion of that portion of the fluid in which it is immersed, and, by the aid of a small pencil, its direction is inscribed upon a plate located above it. by placing this registering apparatus in different directions the entire liquid may be explored. we find by this means figures that are perfectly identical with magnetic phantoms. all the circumstances connected with these can be reproduced, the vibrating sphere giving the phantom of a magnet with its two poles. we may even exhibit the mutual action of two magnets. the figures show with remarkable distinctness--much more distinct, perhaps, than those that are obtained by true magnets. [illustration: fig. .] however, it must not be thought that these so interesting facts are the result of groping in the dark and the outcome of some fortunate experiment; for they have, on the contrary, been foreseen and predetermined. mr. bjerknes is especially a mathematician, and it was a study, through calculation, of the vibratory motion of a body or system of bodies in a medium that led him to the results that he afterwards materialized. after the production, by mr. lejeune, of his solutions, mr. bjerknes in entered upon a complete study of the subject, and recognized the fact that the result of such motions was the production of regular mechanical actions. he calculated the directions of these, and, along about , perceived the possibility of reproducing the effects of permanent magnetism. more recently, in , he saw that magnetism by derivation might likewise be explained by those hypotheses, and figured by actions of this kind. it was not till then that he performed the experiments, and submitted a body to the results of calculation. the same process has led him to the conclusion that the action of currents might be represented in the same manner; only, instead of bodies in vibration, it would require bodies in alternating rotation. the effects are much more difficult to ascertain, since it is necessary to employ viscid liquids. meanwhile, the experiments have been performed. up to the present time attractions and repulsions have not been shown, and i do not know whether mr. bjerknes has obtained them. but, by the process pointed out, the lines of action (electric phantoms, if i may so express myself) have been traced, and they are very curious. by supposing the current perpendicular to the plate, and in the presence of the pole of a magnet, the influences produced around it are very well seen, and the figures are very striking, especially in the case of two currents. mr. bjerknes does not appear as yet to have obtained from these experiments all that he expects from them. and yet, such as they are, they have already led him to important conclusions. thus, calculation, confirmed by application, has led him to renounce the formula proposed by ampère and to adopt that of regnard as modified by clausius. is he right? this is what more prolonged experimentation will allow to be seen. these researches, however, are beset with difficulties of a special nature, and the use of viscid liquids is a subject for discussion. mr. bjerknes desired to employ them for reproducing the effects that he had obtained from water, but he found that the lines of force were no longer the same, and that the phenomena were modified. it is necessary, then, to hold as much as possible to liquids that are perfect. the experimenter is at present endeavoring to use these liquids by employing cylinders having a fluted surface; but it is clear that this, too, is not without its difficulties. this series of experiments offers a rare example of the verification of algebraic calculation by direct demonstration. in general, we may employ geometry, which gives a graphic representation of calculation and furnishes a valuable control. sometimes we have practical application, which is a very important verification in some respects, but only approximate in others. but it is rare that we employ, as mr. bjerknes has done, a material, direct, and immediate translation, which, while it brings the results into singular prominence, permits of comparing them with known facts and of generalizing the views upon which they are based. hypotheses as to the nature of electricity being as yet only tolerably well established, we should neglect nothing that may contribute to give them a solid basis. assuming that electricity _is_ a vibratory motion (and probably there is no doubt about it), yet the fact is not so well established with regard to it as it is to that of light. every proof that comes to support this idea is welcome, and especially so when it is not derived from a kind of accident, but is furnished by a calculated and mathematical combination. viewed from this double standpoint, the experiments of mr. bjerknes are very remarkable, and, i may add, they are very curious to behold, and i recommend all visitors to the exhibition to examine them.--_frank geraldy, in la lumiere electrique._ * * * * * the arc electric light.[ ] [footnote : a recent address before the new york electric light association.] by leo daft. i shall experience one difficulty in addressing you this evening, which is, that although i do not wish to take up your time with purely elementary matter, i wish to make the subject clear to those who may not be familiar with its earlier struggles. if we begin at the beginning we have to go back to the time when faraday made the discovery that light could be produced by the separation of two carbon rods conducting a current of considerable tension. that is the historical point when electric lighting first loomed up as a giant possibility of the near future. this occurred about the year . in some experiments he found that although the circuit could not be interrupted by any considerable interval when metallic terminals were used without breaking the current, when carbon was substituted the interval could be largely increased, and a light of dazzling brilliancy appeared between the points. this remarkable effect appears to be produced by the rarefaction of the air, due to the great heat evolved by the combustion of the carbon, and also to the passage of incandescent particles of carbon from pole to pole, thus reducing the resistance, otherwise too great for the current tension. that was the beginning of electric lighting; and perhaps it will be well to bridge the long and comparatively uninteresting interval which elapsed between this discovery and the equally important one which alone gave it commercial value--i refer to the production of suitable currents by mechanical means. that is to say, the substitution of energy obtained from coal in the form of steam power reduced the cost to a fraction of what it necessarily was when the galvanic elements were used. here is the point; the cost of zinc today is something over fifty times that of coal, while its energy as a vitalizing agent is only about five times greater, leaving a very large margin in favor of the "black diamonds." this is not the only advantage, for the resulting impulse in the case of mechanical production is much more uniform in action, and therefore better suited to the end in view, while the amount of adjustment and attention required is beyond comparison in favor of the latter means. the machines adopted were of the magneto variety, and many ingenious machines of this class were operated with more or less success, being, however, quickly abandoned upon the introduction of the dynamo-machine, which gave currents of much greater electromotive force from the same amount of material, the advantage being chiefly due to the large increase of magnetic intensity in the field magnets. at this period lights of enormous power were produced with ease and by the use of costly lamps. with complicated mechanism a new era in artificial illumination seemed close at hand, but a grave difficulty stood in the way--namely, the proper distribution or subdivision of the light. it was quickly found that the electric difficulty of subdividing the light, added to the great cost of the lamps then made, was an apparently insurmountable obstacle to its general adoption, and the electric light was gradually taking its place as a brilliant scientific toy, when the world was startled by the introduction of the jablochkoff candle, which may fairly claim to have given a greater impetus to the new light than any previous invention, a stimulus without which it is even probable that electric lighting might have slumbered for another decade. the jablochkoff candle embodies a very beautiful philosophical principle, and though its promises have not been fulfilled in general practice, we must not forget that we owe it much for arousing scientific men from a dangerous lethargy. up to this time the light had always been produced by approximation of carbon rods with their axes in the same plane; but the jablochkoff candle consisted of like rods arranged parallel to each other and about one-eighth of an inch apart, the intervening space being filled with plaster of paris, and the interval at the top bridged by a conducting medium. the object of the plaster, which is a fairly good insulating material at ordinary temperatures, is to prevent the passage of the current except at the top, where the conducting material just referred to assisted the formation of the arc at that point, and the resulting intense heat maintained the plaster in a moderately conducting state until the whole carbon was consumed. here, then, was literally an electric "candle," which could be operated without the costly and unsteady lamps, and fortunately its birthplace was paris--then the center of philosophical research; from that period the future of electric lighting was assured. when we reflect that owing to the greater disruptive energy of the positive terminal, the carbon so connected to an ordinary dynamo machine is consumed very much faster than the negative--sometimes in the ratio of to --it will be clear that some other means of consuming the jablochkoff candle had to be used, since the arc would cease to exist in a very short time by reason of the unequal consumption of the carbons, and the subsequent increase of the intervening space beyond the limit of the current tension. this difficulty m. gramme overcame with characteristic ingenuity by adding to the ordinary system a "distributer" capable of delivering plus and minus currents alternately, thus equalizing the consumption, besides being able to supply a large number of candles on the multiple circuit system, each circuit supporting four or five lamps. thus it will be seen that a result was attained which at least gave such men as siemens, gramme, and their peers, if such there be, confidence in the future and a courage which quickly placed the new science safely beyond the limits of the laboratory. i will not occupy your time by stating the apparent reasons why the jablochkoff candle has not fully sustained its brilliant promise--it will, perhaps, be sufficient to state that it is now superseded practically, though it must always occupy an honorable place in scientific annals. let us now for a few moments consider what the electric light really accomplished at about this period, i mean from an economical standpoint. it appears from some data furnished by an engineer commissioned by the french government that the machines were then capable of maintaining a light equal to from to candles, measured by comparison with the carcel burner, per horse power absorbed--a very good showing considering the youth of the discovery, but presenting rather a gloomy aspect when we consider that according to joule's mechanical equivalent of heat, which is foot pounds, or the power required to raise one pound of water one degree--and for lack of anything better, we are obliged to accept that at this moment--the whole force contained in one pound of coal would maintain a light equal to , candles for one hour! that is the ultimate force, and what we are now able to accomplish is but a small fraction of this amount. unfortunately we are but common mortals, and cannot, like mr. keely, lightly throw off the trammels of natural law; we must, therefore, endeavor to close this gap by patient study and experiment. the limited time at my disposal, and a keen consideration for your feelings, will not permit me to follow the long series of struggles between mind and matter immediately following jablochkoff's brilliant invention; suffice it to say, that the few years just passed have yielded beyond comparison the most marvelous results in the scientific history of the world, and it will be superfluous to remind you that a great part of this has undoubtedly been due to the researches made in an effort to reduce electric lighting to a commercial basis. to say that this has been fully accomplished is but to repeat a well known fact; and in proof of this i quote a high scientific authority by stating that a result so high as , candles evolved for , foot-pounds absorbed has recently been obtained--an efficiency six or seven times greater than the record of six years ago. in accepting this statement we must not lose sight of the extreme probability that such effects were evolved under conditions rarely if ever found in common practice. of course, i now refer to the arc system. the volume of light so generated is incomparably greater than by any other known method, though in subdivision the limit is sooner reached. mr. hawkesworth--let me ask you a question, please. supposing that it required a one-horse power to produce an arc light of, say, , candles, would it be possible to produce ten arc lights of candles each? mr. daft--no, sir; i will tell you why. it would, if no other element than the simple resistance of the arcs opposed the passage of a current; then a machine that would produce an inch arc in one light, if placed on a circuit of sixteen lamps would give to each an arc one-sixteenth of an inch long naturally; but another difficulty here presents itself in the shape of a resisting impulse of considerable electromotive force in the opposite direction, apparently caused by the intense polarity of the two terminals. the resistance of the arc itself varies much according to the volume of current used being usually small with a large quantity of current, and greater with a current of tension; but this opposing element is always found, and appears to be the only real obstacle in the way of infinite subdivision. almost every objection which human ingenuity could suggest has been urged against lighting by electricity, but fortunately electricians have been able in most cases either to meet the difficulty or prove it groundless. in this connection i am led to speak of the common idea that electric light is injurious to the eyes, first, because of its unsteady character, and secondly, by reason of the great excess of the more refrangible rays. both objections undoubtedly hold good where the alleged causes exist; but we can now show you a light which is certainly as steady as the ordinary gaslight--indeed more steady in an apartment where even feeble currents of air circulate; and i am sure you will readily acknowledge that the latter objection is disposed of when i assure you that our light presents the only example with which i am acquainted of an exact artificial reproduction of the solar light, as shown by decomposition. the two spectra, placed side by side, show in the most conclusive manner the identity in composition of our light with that of the sun. the remarkable coolness of the electric light, as compared with its volume by gas, is also due in a great measure to the conspicuous absence of that large excess of less refrangible, or heat-radiating principle, which distinguishes almost equally all other modes of artificial illumination. after the foregoing statement it may seem a paradox to claim that the electric arc develops the greatest heat with which we have yet had to deal, but this is so; and the heat has an intensity quite beyond the reach of accurate measurement by any instrument now known--it has been variously estimated anywhere between , ° and , ° f. it is sufficient for our present purpose to know that the most refractory substances quickly disappear when brought under its influence--even the imperial diamond must succumb in a short time. in order to reconcile this fact with its coolness as an illuminating agent, we have to take into consideration the extreme smallness of the point from which the light radiates in the electric arc. a light having the power of many thousand candles will expose but a fraction of the surface for heat radiation which is shown by one gas-jet, and, as i have endeavored to explain, these rays contain very much less of the heating principle than those from gas or other artificial light. the purity of electric light has another important aspect, which can scarcely be overestimated--namely, the facility with which all the most delicate shades of color can be distinguished. i understand from persons better skilled than myself in such matters that this can be done almost as readily by electric as by day light, and i have little doubt that the slight difference in this respect will entirely disappear when people become somewhat more familiar with the different conditions--the effect of such shades viewed by electric light being more like that with comparatively feeble direct sunlight than the subdued daylight usually prevailing in stores and warehouses. again, it has frequently been urged that persons working by electric light have thus induced inflammation of the eyes. no doubt this is so with light containing the highly refrangible rays in excess; but it is difficult to see how such an effect can occur with light composed as is the light with which the eyes are constructed to operate in perfect harmony. as you are aware, there are other methods of obtaining light by electric energy, and in order to make a fair comparison of one which has lately attracted a great deal of attention and capital, i will relate to you the result of observations made during a recent visit to the office of an eminent electrician. the light was that known as incandescent--a filament of carbon raised to a light-emitting heat in vacuo. the exclusion of the air is necessary to prevent the otherwise rapid destruction of the carbon by combination with oxygen. at the time of my visit there were lamps in circuit. according to their statement each lamp was of -candle power--i accept their statement as correct; this will give us an aggregate of candles. the generator was vitalized by an engine rated by the attendants in charge at -horse power. i found that it was a × cylinder, working with very little expansion revolutions per minute, with pounds of live steam, in a boiler not feet from the engine. i have every reason to believe that the steam was delivered at the cylinder with an almost inappreciable loss on pounds. under those conditions i think it is perfectly fair to assume (you have the data, so that you can calculate it afterwards) that , foot pounds were consumed in producing those lights, aggregating candles. in the kind of engine they had, , foot pounds requires a consumption of about pounds of coal per hour. it was an ordinary high speed engine. that , foot pounds, i assume, required pounds of coal. that is the only weak point in my data; i do not know that to be true; but i never saw an engine of that form yet capable of delivering -horse power with less consumption than four to five pounds of coal per horse power per hour. i want to be as fair as i can in the matter. i wish to compare this, as they have taken particular pains to compare it, with gas, at the present cost of gas. the hundred pounds of coal will produce feet of gas; feet of gas will evolve the effect of , candles. so you see the position we are in. in consuming that coal directly by destructive distillation you can produce , candles light; by converting it into power, and then again into light by incandescence, you produce ! expressing this in other words, we may say that in producing the light from coal by the incandescent system you lose one-third of the power as compared with gas, by actually converting the coal into gas, and delivering it in the ordinary manner. those are facts. it has been suggested to me that i am too liberal in my estimate of coal consumed--that those engines consume more than four or five pounds per horse power per hour; but i prefer to give them the benefit of the doubt. mr. rothschild--if i understood you correctly, this electric light costs more than gas? mr. daft--_must_ do by this system. you cannot do better, so far as our philosophy goes. but this whole system of illumination, as now practiced is a financial fallacy. mr. rothschild--that is what professor sawyer says. mr. daft--the same amount of energy converted into light by our arc system will produce , candles. we are perfectly willing to demonstrate that at any time. i am free to admit that the minute subdivision obtained by the edisonian, swan, or fox system--they do not differ materially--is a great desideratum; but this cannot bridge the financial gulf. mr. lendrum--now please state what we have accomplished. mr. daft--certainly; and in so doing i prefer to give our results as actually occurring in everyday work; and in this connection let me remind you that in no branch of physics are the purely experimental effects so well calculated to deceive, if not fairly conditioned. as we have seen, it is claimed on excellent authority that the equivalent of , candles appeared in an arc by expending , foot pounds of energy at the generator, but with everyday conditions it is at present idle to expect such efficiency. commercially we can give by our own system , candles for , foot pounds absorbed; this may be done for an indefinite length of time and leave nothing to be desired on the score of steadiness. unfortunately there is no unit of photometric measurement generally recognized in this country, each electrician having so far adopted one to suit his own convenience; but in making the foregoing statement i wish it to be understood that our efficiency would appear still greater if measured by some of the methods now employed. for our own satisfaction we have endeavored to be at least approximately accurate, at the same time wishing to avoid the affectation of extreme precision, such, for example, as adding twenty or thirty candles to measurements of so many thousands, and we are satisfied that the most critical expert tests will prove our claim to be within the mark. the limit of subdivision is only reached when the difficulty of further increasing the electromotive force of the machines, involving great care in insulation and a host of other troubles arising, so to speak, at very high pressure, is balanced by the objections to working in multiple arc; this appears to occur now at something below lights, but will in all probability be greatly extended within a short time. the machines are so constructed that the local currents, usually productive of dangerous heating, are turned to useful account, so that the point where radiation exceeds production is soon reached, and provided the machines are not speeded beyond the proper limit, they may be run continuously without the slightest indication of lost vitality. i need scarcely remind you that this is a most important feature, and by no means a common one. the lamps used in our system i believe to be the simplest known form of regulator; indeed it seems scarcely possible that anything less complicated could perform the necessary work; as a matter of fact we may confidently assert that it cannot be made less liable to derangement. it has frequently been placed on circuit by persons totally inexperienced in such matters, and still has yielded results which we are quite willing to quote at any time. i will not now trespass on your patience further than will enable me to state that experiments now in hand indicate conclusively that domestic electric lighting of the immediate future will be accomplished in a manner more beautiful and wondrous than was ever shadowed in an arabian night's dream. i hesitate somewhat to make these vague allusions, since so many wild promises, for which i am not responsible, remain unfulfilled, but the time is surely near at hand when a single touch will illuminate our homes with a light which will combine all the elements of beauty, steadiness, softness, and absolute safety, to a degree as yet undreamed of. i do not ask you to accept this without question, but only to remember that within the last decade wires have been taught to convey not only articulate sounds, but the individual voices you know amidst a thousand, and even light and heat have each been made the medium of communicating our thoughts to distant places! not the least remarkable phenomenon in this connection is the intellectual condition of the people who have welcomed these marvelous achievements and allowed them to enter into their everyday life, thus removing the greatest barriers of the past and paving the way for that philosophical millennium inevitably awaiting those who may be fortunate enough to survive the next decade. * * * * * success of the elevated railways, new york. the travel over the elevated steam street railways of new york city for month of october, , was the heaviest yet recorded, aggregating , , passengers, as against , , , for the corresponding month of , an increase of , , , representing just about the entire population of the city. * * * * * hedges' electric lamps. we illustrate a very curious and interesting form of electric regulator which is exhibited in the paris exhibition of electricity by mr. killingworth hedges, whose name will be known to our readers as the author of a little book on the electric light. mr. hedges' lamp belongs to the same category of electric regulators as the lamp of m. rapieff, and to one form of m. reynier's lamp, that is to say, the position of the ends of the carbons, and therefore of the arc, is determined not by clockwork or similar controlling mechanism, but by the locus of the geometrical intersection of the axes of the carbon rods, the positions of which axes being determined by simple mechanical means. [illustration: figs. and hedges' electrical lamp at the paris electrical exhibition.] referring to fig. , a and b are two troughs rectangular in cross section attached to the supports in such positions that their axes are inclined to one another so as to form the letter v, as shown in the figure. within these troughs slide freely the two carbon pencils, which are of circular cross section, meeting, when no current is passing, at the lower point, e. the carbon-holder, b, to the right of the figure, is rigidly attached to the framing of the lamp, but the trough, a, which carries the negative carbon, is attached to the framing by a pivot shown in the figure, and on this pivot the carbon holder can rock, its motion being controlled by the position of the armature of an electro-magnet, m, the coils of which are included in the circuit of the apparatus. by this means, the moment the current is established through the lamp, the armature is attracted, and the points of the two carbons are separated, thus forming the arc. the positive carbon, b, is held from sliding and dropping through the trough by the gentle pressure against it of the smaller carbon rod, c¹, which also slides in a trough or tube fixed in such a position that the point of contact between the two rods is sufficiently near the arc for the smaller rod to be slowly consumed as the other is burnt away; the latter in that way is permitted to slide gradually down the trough as long as the lamp is in action. the negative carbon-holder, a, is provided with a little adjustable platinum stop, e, which by pressing against the side of the conical end of the negative carbon, holds the latter in its place and prevents it sliding down the trough except under the influence of the slow combustion of the cone during the process of producing the arc. the position of the stop with respect to the conical end is determined by a small adjusting screw shown in the figure. this arrangement of stop is identical in principle with that adopted by messrs. siemens brothers in their "abutment pole" lamp, and is found to work very well in practice on the negative electrodes, but is inapplicable on the positive carbons on account of the higher temperature of the latter, which is liable to destroy the metallic stop by fusion, and it is for this reason that the positive carbon in mr. hedges' lamp is controlled by the method we have already described. for alternating currents, however, the abutment stop may be used on both electrodes. [illustration: figs. and .] in order to maintain a good electrical contact between the fixed conducting portions of the lamp and the sliding carbons, mr. hedges fits to each carbon-holder a little contact piece, f f, hinged to its respective trough at its upper end, and carrying at its lower or free end a somewhat heavy little block of brass grooved out to fit the cylindrical side of the carbon, against which it presses with an even pressure. this arrangement offers another advantage, namely, that the length of that portion of the carbon rods which is conveying the current is always the same notwithstanding the shortening of their total length by combustion; the resistance of the carbon electrodes is, therefore, maintained constant, and, for the reason that the contact piece presses against the rods very near their lower ends, that resistance is reduced to a minimum. in this way very long carbons, such, for instance, as will burn for ten or sixteen hours, can be used without introducing any increase of resistance into the circuit. the length of the arc can be determined by the adjustment of the screw, g, by which the amount of movement of the armature is limited. fig. represents a modified form of mr. hedges' lamp designed for installation when it is desirable to burn a number of lamps in series. in this arrangement the carbons are separated by the attractive influence of a solenoid upon an iron plunger, to which is attached (by a non-magnetic connection) the armature of an electro-magnet, the coils (which are of fine wire) forming a shunt circuit between the two terminals of the lamp, and so disposed with respect to the armature as to influence it in an opposite direction to that of the solenoid. when the circuit of the lamp is completed with the electric generator the carbons are drawn apart by the action of the solenoid on the plunger, and the distance to which they are separated is determined by the difference of attractive force exercised upon the armature by the solenoid and the magnet; but as the latter forms a short circuit to that of the arc, it follows that should the resistance of the arc circuit increase either through the arc becoming too long or through imperfection in the carbons or contacts, a greater percentage of current will flow through the magnet coils, and the arc will be shortened, thereby reducing its resistance and regulating it to the strength of the current. in other words, the distance between the carbons, that is to say, the length of the arc, is determined by the position of the armature of the electro-magnet between its magnets and the solenoid, which position is in its turn determined by the difference between the strength of current passing through the coil of the solenoid and that of the magnet. mr. killingworth hedges exhibits also a third form of his lamp, in most respects similar to the lamp figured in fig. , but in which the ends of the two carbons rest against the side of a small cylinder of fireclay or other refractory material, which is mounted on a horizontal axis and can be rotated thereon by a worm and worm-wheel actuated by an endless cord passing over a grooved pulley. in the lamp one of the carbon-holders is rigidly fixed to the framing of the apparatus, and the other is mounted on a point so as to enable the length of the arc playing over the clay cylinder to be regulated by the action of an electro-magnet attracting an armature in opposition to the tension of an adjustable spring. in the same exhibit will be found specimens of mr. hedges' two-way switches, which have been designed to reduce the tendency to sparking and consequent destruction which so often accompanies the action of switches of the ordinary form. the essential characteristic of this switch, which we illustrate in elevation in fig. and in plan in fig. , lies first in the circular form of contact-piece shown in fig. , and next in the fact that the space between the two fixed contact-pieces is filled up with a block composed of compressed asbestos, the surface of which is flush with the upper surfaces of the two contact-pieces. the circular contact-piece attached to the switch lever can be turned round so as to present a fresh surface when that which has been in use shows indications of being worn, and a good firm contact with the fixed contact-pieces is insured by the presence of a spiral spring shown in the upper figure, and which, owing to an error in engraving, appears more like a screw than a spring. in order to prevent bad connection through dust or other impurities collecting within the joint, the electrical connection between the fulcrum of the switch lever and the circular contact-piece is made through the bent spring shown edgeways in fig. .--_engineering._ * * * * * railway apparatus at the paris electrical exhibition. [illustration: fig. .--lartigue's switch controller fig. --transverse section fig. --longitudinal section fig. .--position of the commutators during the manuever fig. .--pedal for sending warning to railway crossing--elevation. fig. .--end view. fig. .--electric alarm. fig. .--guggemos's correspondence apparatus--external view. fig. .--interior of the same. fig. .--annunciator apparatus. fig. .--controller for water tanks (lartigue system). railway apparatus at the paris electrical exhibition.] [illustration: fig. .--pedal for sending warning to railway crossing--plan view. fig. .--lartigue's bellows pedal--longitundinal section fig. .--general plan. fig. .--controller for water tanks (vérité system). railway apparatus at the paris electrical exhibition.] _lartigue's switch controller._--the object of this apparatus is to warn the switch tender in case the switch does not entirely respond to the movement of the maneuvering lever. the apparatus, which is represented in the accompanying figs. , , , and , consists of the following parts: ( .) a mercurial commutator, o, which is fixed on a lever, b, connected with a piece, a, which is applied against the external surface of the web of the main rails, opposite the extremity of the switch plates; ( .) a bar, c, which traverses the web of the rail and projects on the opposite side, and which carries a nut, d, against which the switch plate abuts; ( .) an electrical alarm and a pile, located near the switch lever. as long as one of the two plates of the switch is applied against the rail, one of the two commutators is inclined and no current passes. a space of one millimeter is sufficient to bring the commutator to a horizontal position and to cause the electric alarm to ring continuously. if the apparatus gets out of order, it is known at once; for if the alarm does not work during the maneuver of the switch, the tender will be warned that the electric communications are interrupted, and that he must consequently at once make known the position of his switch until the necessary repairs have been made. _pedals for transmitting signals to crossings._--on railways having a double track and doing a large amount of business it becomes very necessary to announce to the flagmen at railway crossings the approach of trains, so as to give them time to stop all crossing of the tracks. on railway lines provided with electro-semaphores there may be used for this purpose those small apparatus that have been styled semaphore repeaters. mr. lartigue has invented two automatic apparatus, by means of which the train itself signals its approach. . the first of these, which is generally placed at about , feet from the point to be covered, consists (figs. , , , and ) of a very light pedal fixed to the inside of the rail, and acting upon a mercurial commutator. a spring, r, carried upon the arm, a, of a lever, a, projects slightly above the level of the rail, while the other arm, b, carries a commutator. the spring, r, on being depressed tilts the box containing the mercury, closes the circuit, and causes an alarm, s, located at the crossing, to immediately ring. in this alarm (fig. ) a piece, p, is disconnected by the passage of the current into the electro-magnet, e, which attracts the armature, a, and, a permanent current being set up, the apparatus operates like an ordinary alarm, until the piece, p, is placed by hand in its first position again. . the second apparatus, exhibited by the railway company of the north, and also the invention of mr. lartigue, bears the name of the "bellows pedal." it consists (figs. and ) of a pedal, properly so called, p, placed along the rail, one of its extremities forming a lever and the other being provided with a counterpoise, c. when a train passes over the pedal, the arm, b, fixed to its axle, on falling closes the circuit of an ordinary electrical alarm, and at the same time the bellows, s, becomes rapidly filled with air, and, after the passage of the train, is emptied again very slowly under the action of the counterpoise. the contact is thus kept up for some few minutes. this apparatus works very satisfactorily, but is cumbersome and relatively high-priced. _the brunot controller as a controller of the passage of trains._--the brunot controller, which has been employed for several years on the railway of the north, is designed to control the regularity of the running of trains, and to make automatically a contradictory verification of the figures on the slips carried by the conductors. in fig. we give a longitudinal section of the apparatus. it consists of a wooden case containing a clockwork movement, h, upon the axle of which is mounted a cardboard disk, c, divided into hours and minutes, and regulated like a watch, that is to say, making one complete revolution in twelve hours. the metallic pencil, c, which is capable of displacing itself on the cardboard in a horizontal direction opposite a groove on the other side of the disk, traces, when pressure is brought to bear on it, a spiral curve. the transverse travel of the pencil is effected in ninety-six hours. the displacement of the pencil is brought about by means of a cam. under the influence of the jarring of the train in motion, a weight, p, suspended from a flexible strip, l, strikes against the pencil, c, which traces a series of points. during stoppages there is, of course, an interruption in the tracing of the curve. [illustration: fig. .--brunot's controller. railway apparatus at the paris electrical exhibition.] up to this point no electricity is involved--the apparatus is simply a controller of regularity. mr. brunot has conceived the idea of utilizing his apparatus for controlling the passage of trains at certain determined points on the line; for example, at the top of heavy grades. for this purpose it has only been necessary to add to the apparatus that we have just described an electro-magnet, e, connected electrically with a fixed contact located on the line. when the current passes, that is to say, at the moment the circuit is closed by the passage of a train, the armature, a, is attracted, and the pencil marks a point on the cardboard disk. this modification of the apparatus has not as yet been practically applied. _electrical corresponding apparatus._--the object of these apparatus is to quickly transmit to a distance a certain number of phrases that have been prepared in advance. the company of the north employs two kinds of correspondence apparatus--the guggemos and the annunciator apparatus. . _the guggemos apparatus._--this apparatus serves at once as a manipulator and receiver, and consists of an inner movement surmounted by a dial, over the face of which moves an index hand. around the circumference of the dial there is arranged a series of circular cases, c, containing the messages to be received, and similar triangular cases, containing the messages to be forwarded, radiating from the center of the dial. between each of these there is a button, b. fig. represents the interior of an apparatus for twenty messages. it consists of a key-board, m, an electro-magnet, b, a clock-work movement, q, an escapement, s, and an interrupter, f g. when one of the buttons, b, is pressed, one of the levers of the key-board arrangement touches the disk, m, which is insulated from the other portions of the key-board, and the current then passes from the terminal c to m, and there bifurcating, one portion of it goes to the bobbins of the apparatus and thence to the earth, while the other goes to actuate the correspondence apparatus. the index-hands of the two apparatus thereupon begin their movement simultaneously, and only stop when the pressure is removed from the button and the current is consequently interrupted. h is a ratchet-wheel, which, like the key-board, is insulated from the rest of the apparatus. the button, k, located over each of the dials, serves to bring the index-needles back to their position under the cross shown in fig. . the key, x, serves for winding up the clock-work movement. _the annunciator apparatus._--this apparatus, which performs the same role as the one just described, is simply an ingenious modification of the annunciator used in hotels, etc. it consists of a wooden case, containing as many buttons as there are phrases to be exchanged. over each button, b, there is a circular aperture, behind which drops the disk containing the phrase. between the buttons and the apertures are rectangular plates, p, in which are inscribed the answers given by pressing on the button of the receiving tablet--a pressure which, at the same time, removes the corresponding disk from the aperture. two disks located at the upper part carry these inscriptions: "error, i repeat;" "wait." the tablets on exhibition have eight disks, and can thus be used for exchanging six different phrases. in the interior, opposite each aperture, there is a hughes magnet, between the arms of which there oscillates a vertical soft-iron rod, carrying a disk. the maneuver "is simple." by pressing upon a button there is sent into the bobbins of the magnet corresponding to this button a current which causes the disk to appear before one of the apertures, while at the same time an alarm begins to ring. the same maneuver performed by the agent at the receiving-post has the effect of causing the disk to disappear. the two contact springs in communication at each aperture with the alarm and the line are connected by a strip of ebonite, m, against the center of which presses the button. _electrical controllers for water-tanks._--the object of these apparatus is to warn the person in charge of a water-tank that the latter is full, and that he must stop the engine-pump; or, that the tank is empty, and that he must at once proceed to fill it. the company of the north has on exhibition two such apparatus--one of them lartigue's, and the other vérité's. . _the lartigue controller_ (fig. ).--this apparatus consists of a long lever, a, which carries at one of its extremities a funnel, e, having a very narrow orifice and which is placed under the overflow pipe of the tank. the lever is kept normally in a horizontal position by a counterpoise; but, as soon as the overflow runs into the funnel, the weight of the water tilts the lever, and the mercurial commutator, f, closes the circuit of a pile, which actuates an alarm-bell located near the pump and engine. the two stops, a and _a'_, limit the play of the lever. . _the vérité controller_ (fig. ).--this apparatus consists of a float, f, provided with a catch, c, calculated in such a way as to act only when the float has reached a certain definite height. at that moment it lifts the extremity of the weighted lever, e, which in falling back acts upon the extremity, a, of another lever, n, pivoted at the point, o. the piece, p, which is normally in contact with the magnet, a, being suddenly detached by this movement of the lever, n, the induced current which is then produced causes the display, near the pump, of a disk, q, upon which is inscribed the word "full." this is a signal to stop pumping. * * * * * the telephonic halls of the electrical exhibition. telephonic communication between the opera and the exhibition of electricity is obtained by means of twenty conducting wires, which are divided between two halls hung with carpets to deaden external noises. we represent in the accompanying engraving one of these halls, and the one which is lighted by the lane-fox system of lamps. as may be seen, there are affixed against the hangings, all around the room, long mahogany boards, to which are fastened about twenty small tablets provided with hooks, from which are suspended the telephones. the latter are connected with the underground conductors by extensible wires which project from the wooden wainscot of which we have just spoken, so that it is very easy for the auditors to put the telephones to their ears. [illustration: one of the telephonic halls at the electrical exhibition.] as the telephones are connected in series of eight with the same couple of microphone transmitters, and as each of these transmitting couples occupies a different position on the stage, it results that the effects are not the same at different points of each hall. those telephones, for example, which correspond with the foot-lights of the theater are more affected by the sounds of the large instnuments of the orchestra than those which occupy the middle of the foot-lights; but, as an offset to this, the latter are affected by the voice of the prompter. in order to equalize the effects as much as possible, mr. ader has arranged it so that the two transmitters of each series shall be placed under conditions that are diametrically opposite. thus, the transmitter at the end of the foot-lights, on the left side, corresponds with the transmitter of the series to the right, nearest to the middle of the stage; and the arrangement is the same, but in an inverse direction, for the transmitter at the end of the foot-lights to the right. but the series which produces the best effects is, as may be readily comprehended, that which corresponds with the transmitters occupying the middle of the right and left rows. these considerations easily explain the different opinions expressed by certain auditors in relation to the predominant sounds that they have heard, and why it is that some of them who have listened in different parts of the same hall have not had the same impressions. naturally, the fault has beeen laid to the telephones; but, although these may vary in quality, it is more particularly to the arrangement of the transmitters on the stage that are to be attributed the differences that are noted. as the opera does not give representations every day, mr. ader has had the idea of occupying the attention of the public on tuesday, thursday, saturday, and sunday with the telephonic effects of flourishes of trumpets, which imitate pretty well the effects of french horns. these experiments have taken place in the hall in which is installed the little theater, and we must really say that in the effects produced french horns count for nothing.--_la lumiere electrique._ * * * * * the action of cold on the volt when the voltaic arc plays between two metallic rheophores, of copper for instance, each formed of a u-tube traversed by a rapid current of cold water, and placed horizontally opposite each other, the following facts are observed: the luminous power of the arc is considerably weakened; it is reduced to a mere luminous point even when a current of to bunsen elements of the large pattern is employed. the arc is very unstable and the least breath is sufficient to extinguish it. if a leaf of paper is placed above the arc at the distance of . to . meter a black point is produced in a few moments, which spreads and becomes a perforation, but the paper does not ignite. the arc consists of a luminous globule, moving between the two rheophores up and down and back again. the form of this globule, as well as its extreme mobility, causes it to resemble a drop of water in a spheroidal state. if we approach to the voltaic arc the south pole of a magnet the arc is attracted to such a degree that it leaves the rheophores and is extinguished. the same facts are observed in an intense form on presenting the north pole of a magnet to the arc. the quantity of ozone seems greater than when the arc is not refrigerated. it is to be noted that notwithstanding the refrigeration of the rheophores the flame of the arc is slightly green, proving that a portion of the copper is burning. it becomes a question whether the arc would be produced on taking as rheophores two tubes of platinum in which is caused to circulate, e.g., alcohol cooled to - °.--_d. tommasi._ * * * * * watchman's detecter. we herewith illustrate an exceedingly simple form of detecter, to show if the night watchmen perform their visits regularly and punctually. in the case, c, is a clockwork apparatus driving the axle, s, at the end of which is a worm which gears into the wheel of the drum, d. the rotation of d, thus obtained unrolls a strip of paper from the other drum, d. this paper passes over the poles of as many electro-magnets as there are points to be visited, and underneath the armatures of these electro-magnets. each armature has a sharp point fixed on its under side, and when a current passing through the coils causes the attraction of the armature, this point perforates the paper. the places to be visited are connected electrically with the binding screws shown, and the watchman has merely to press a button to make the electric circuit complete. it has been found in practice that plain paper answers every purpose, as the clock giving an almost uniform motion enables the reader, after having seen the perforated slips once or twice, to determine fairly well the time which elapses between each pressure of the button.--_the engineer._ [illustration: watchman's detecter] * * * * * integrating apparatus. at a recent meeting of the london physical society, mr. c. vernon boys read a paper on "integrating apparatus." after referring to his original "cart" machine for integrating, described at a former meeting of the society, he showed how he had been led to construct the new machine exhibited, in which a cylinder is caused to reciprocate longitudinally in contact with a disk, and give the integral by its rotation. integrators were of three kinds: ( ) radius machines; ( ) cosine machines; ( ) tangent machines. sliding friction and inertia render the first two kinds unsuitable where there are delicate forces or rapid variation in the function to be integrated. tangent machines depend on pure rolling, and the inertia and friction are inappreciable. they are, therefore, more practical than the other sort. it is to this class that mr. boys' machines belong. the author then described a theoretical tangent integrator depending on the mutual rolling of two smoke rings, and showed how the steering of a bicycle or wheelbarrow could be applied to integrate directly with a cylinder either the quotient or product of two functions. if the tangent wheel is turned through a right angle at starting, the machine will integrate reciprocals, or it can be made to integrate functions by an inverse process. if instead of a cylinder some other surface of evolution is employed as an integrating surface, then special integrations can be effected. he showed a polar planimeter in which the integrating surface is a sphere. a special use of these integrators is for finding the total work done by a fluid pressure reciprocating engine. the difference of pressure on the two sides of the piston determines the tangent of the inclination of the tangent wheel which runs on the integrating cylinder; while the motion of the latter is made to keep time with that of the piston. in this case the number of evolutions of the cylinder measures the total amount of work done by the engine. the disk cylinder integrator may also be applied to find the total amount of work transmitted by shafting or belting from one part of a factory to another. an electric current meter may be made by giving inclination to the disk, which is for this purpose made exceedingly small and delicate, by means of a heavy magnetic needle deflected by the current. this, like edison's, is a direction meter; but a meter in which no regard is paid to the direction of the current can be made by help of an iron armature of such a shape that the force with which it is attracted to fill the space between the poles of an electro-magnet is inversely as its displacement. then by resisting this motion by a spring or pendulum the movement is proportional to the current, and a tangent wheel actuated by this movement causes the reciprocating cylinder on which it runs to integrate the current strength. mr. boys exhibited two such electric energy meters, that is, machines which integrate the product of the current strength by the difference of potential between two points with respect to time. in these the main current is made to pass through a pair of concentric solenoids, and in the annular space between these is hung a solenoid, the upper half of which is wound in the opposite direction to the lower half. by the use of what mr. boys calls "induction traps" of iron, the magnetic force is confined to a small portion of the suspended solenoid, and by this means the force is independent of the position. the solenoid is hung to one end of a beam, and its motion is resisted by a pendulum weight, by which the energy meters may be regulated like clocks to give standard measure. the beam carries the tangent wheels, and the rotation of the cylinder gives the energy expanded in foot-pounds or other measures. the use of an equal number of turns in opposite directions on the movable solenoid causes the instrument to be uninfluenced by external magnetic forces. mr. boys showed on the screen an image of an electric arc, and by its side was a spot of light, whose position indicated the energy, and showed every flicker of the light and fluctuation of current in the arc. he showed on the screen that if the poles are brought too near the energy expended is less, though the current is stronger, and that if the poles are too far apart, though the electromotive force is greater the energy is less; so that the apparatus may be made to find the distance at which the greatest energy, and so the greatest heat and light, may be produced. at the conclusion of the paper, prof. w.g. adams and prof. g.c. foster could not refrain from expressing their high admiration of the ingenious and able manner in which mr. boys had developed the subject. * * * * * a canal boat propelled by air. a novelty in canal boats lies in charles river, near the foot of chestnut street, which is calculated to attract considerable attention. it is called a pneumatic canal boat and was built at wiscasset, me., as devised by the owner, mr. r.h. tucker, of boston, who claims to hold patents for its design in england and the united states. the specimen shown on charles river, which is designed to be used on canals without injuring the banks, is a simple structure, measuring sixty-two feet long and twenty wide. it is three feet in depth and draws seventeen inches of water. it is driven entirely by air, root's blower no. being used, the latter operated by an eight-horse-power engine. the air is forced down a central shaft to the bottom, where it is deflected, and, being confined between keels, passes backward and upward, escaping at the stern through an orifice nineteen feet wide, so as to form a sort of air wedge between the boat and the surface of the water. the force with which the air strikes the water is what propels it. the boat has a speed of four miles an hour, but requires a thirty-five-horsepower engine to develop its full capabilities. the patentee claims a great advantage in doing away with the heavy machinery of screws and side-wheels, and believes that the contrivance gives full results, in proportion to the power employed. it is also contrived for backing and steering by air propulsion. owing to the slight disturbance which it causes to the water, it is thought to be very well adapted for work on canals without injury to the sides.--_boston journal._ * * * * * head linings of passenger cars. the veneer ceilings are considered as much superior to cloth as cloth was to the roof-ceiling. they are remarkably chaste, and so solid and substantial that but little decoration is necessary to produce a pleasing effect. the agreeable contrast between the natural grain of the wood and the deeper shade of the bands and mouldings is all that is necessary to harmonize with the other parts of the interiors of certain classes of cars--smoking and dining cars, for example. but in the case of parlor and dining-room cars, the decorations of these ceilings should be in keeping with the style of the cars, by giving such a character to the lines, curves, and colors, as will be suggestive of cheerfulness and life. while these head linings are deserving of the highest commendation as an important improvement upon previous ones, they are still open to some objections. one barrier to their general adoption is their increased cost. it is true that superior quality implies higher prices, but when the prices exceed so much those of cloth linings, it is difficult to induce road managers to increase expenses by introducing the new linings, when the great object is to reduce expenses. another objection to wood linings is their liability to injury from heat and moisture, a liability which results from the way in which they are put together. a heated roof or a leak swells the veneering, and in many cases takes it off in strips. to obviate these objections, i have, during the past eighteen months, been experimenting with some materials that would be less affected by these causes, and at the same time make a handsome ceiling. about a year ago i fitted up one car in this way, and it has proved a success. the material used is heavy tar-board pressed into the form of the roof and strengthened by burlaps. it is then grained and decorated in the usual manner, and when finished has the same appearance as the veneers, will wear as well, and can be finished at much less cost.--_d.d. robertson._ * * * * * improved mortar mixer. the engravings herewith illustrate a new form of mixing or pugging machine for making mortar or any other similar material. it has been designed by mr. r.r. gubbins, more especially for mixing emery with agglutinating material for making emery wheels; and a machine is at work on this material in the manufactory of the standard emery wheel company, greek street, soho. the machine is shown in perspective in fig. with the side door of the mixing box let down as it is when the box is being emptied; and in fig. it is shown in transverse section. the principle of the machine is the employment of disks fixed at an angle of about deg. on shafts revolving in a mixing box, to which a slow reciprocating movement of short range is given. [illustration: figs. and --improved mortar mixing machine.] in our illustrations, c is a knife-edge rail, upon which run grooved wheels supporting the pugging box. to the axle of one grooved wheel a connecting rod from crank arm, f is attached to effect the to-and-fro motion of the mixing box, b. g is the door of the box, b, hinged at h, and secured by hinged pins carrying fly nuts. a cover and hopper and also a trap may be supplied to the box, b, for continuously feeding and discharging the material operated upon. l, l, are the pugging blades or discs on shafts, m. the shafts, m, pass through a slot in the box, b, and the packing of these shafts is effected by the face plate sliding and bearing against the face on the standard of the machine. p is a guide piece on the standard, against which bears and slides the piece, q, bolted on to box, b, to support and guide the box, b, in its movement. the forked ends of a yoke engage with the collars, s, on the shafts, m, this yoke being set by a screw so that the shafts may be easily removed. the machine is driven from the pulleys and shaft, t, through gearing, t and t , and by the ewart's chain on the wheel and pinion, v and u.--_the engineer._ * * * * * [continued from supplement, no. , page .] practical notes on plumbing.[ ] [footnote : from the london _building news_.] by p.j. davies, h.m.a.s.p., etc. tinning iron pipes, copper or brass-work, bits, etc. previously, i described the method of tinning the bit, etc., with resin; but before this work on joints can be considered complete, i find it necessary to speak of tinning the ends of iron pipes, etc., which have within the last fifty years been much used in conjunction with leaden pipes. this is done as follows: take some spirits of salts (otherwise known as hydrochloric acid, muriatic acid, hydrogen chloride, hcl), in a gallipot, and put as much sheet-zinc in it as the spirit will dissolve; you have then obtained chloride of zinc (zncl). a little care is required when making this, as the acid is decomposed and is spread about by the discharged hydrogen, and will rust anything made of iron or steel, such as tools, etc. it also readily absorbs ammoniacal gas, so that, in fact, sal ammoniac may also be dissolved in it, or sal ammoniac dissolved in water will answer the purpose of the chloride of zinc. having the killed spirits, as it is sometimes called, ready, file the end of your iron or bit and plunge this part into the spirits, then touch your dipped end with some fine solder, and dip it again and again into the spirits until you have a good tinned face upon your iron, etc.; next you require a spirit-brush. spirit-brush. you can make this by cutting a few bristles out of a broom or brush, push them into a short piece of compo tube, say / in., and hammer up the end to hold the bristles; next cut the ends of the bristles to about / in. long, and the brush is ready for use. soldering iron to lead. suppose you want to make a joint round a lead and iron pipe. first file the end of your iron pipe as far up as you would shave it if it were lead, and be sure to file it quite bright and free from grease; heat your soldering-iron; then, with your spirit-brush, paint the prepared end of your iron, and with your bit, rub over the pipe plenty of solder, until the pipe is properly tinned, not forgetting to use plenty of spirits; this done, you can put your joint together, and wipe in the usual manner. caution.--do not put too much heat on your iron pipe, either when tinning or making the joint, or the solder will not take or stand. dummies for pipe-bending. [illustration: figs. . and b.] figs. and b. this tool i had better describe before proceeding to the method of bending. to make it take a piece of, say, ½ in. iron pipe, ft. long, or the length required, bent a little at one end, as shown at a b in fig. and fig. b. tin the end about in. up, make a hole with a small plumbing-iron in some sand, and place the tinned end of the iron pipe, b, into this hole; fill the hole up with good hot lead, and the dummy, after it has been rasped up a little, is ready for use. it will be found handy to have three or four different lengths, and bent to different angles, to suit your work. a straight one (fig. b.) made to screw into an iron socket or length of gas-pipe, will be found very handy for getting dents out of long lengths of soil-pipe. bends and set-offs. before you begin bending solid pressed pipes always put the thickest part of your pipe _at the back_. lead, in a good plumber's hands, may be twisted into every conceivable shape; but, as in all other trades, there is a right and a wrong way of doing everything, and there are many different methods, each having a right and wrong way, which i shall describe. i shall be pleased if my readers will adopt the style most suitable for their particular kind of work; of course i shall say which is the best for the class of work required. for small pipes, such as from ½ in. to in. "_stout_ pipe," you may pull them round without trouble or danger; but for larger sizes, say, from ¼ in. to in., some little care is necessary, even in stout pipes. fig. illustrates a badly made bend, and also shows how it comes together at the throat, x, and back, e; l is the enlarged section of x e, looking at the pipe endways. the cause of this contraction is pulling the bend too quickly, and too much at a time, without dressing in the sides at b b as follows: after you have pulled the pipe round until it just begins to flatten, take a soft dresser, or a piece of soft wood, and a hammer, and turn the pipe on its side as at fig. ; then strike the bulged part of the pipe from x b toward e, until it appears round like section k. now pull your pipe round again as before, and keep working it until finished. if you find that it becomes smaller at the bend, take a long bolt and work the throat part out until you have it as required. [illustration: fig. .] bending with water (light pipes). fig. . this style of bending is much in use abroad, but not much practiced in london, though a splendid method of work. [illustration: fig. .] it is a well known fact that, practically speaking, for such work, water is incompressible, but may be turned and twisted about to any shape, provided it is inclosed in a solid case--fig. is that case. the end, a, is stopped, and the stopcock, b, soldered into the other end. now fill up this pipe quite full with warm water and shut the cock, take the end, a, and pull round the pipe, at the same time dressing the molecules of lead from the throat, c, toward d e, which will flow if properly worked. you can hammer away as much as you please, but be quick about it, so that the water does not cool down, thereby contracting; in fact, you should open the cock now and then, and recharge it to make sure of this. sand bending. this is a very old method of bending lead pipes, and answers every purpose for long, easy bends. proceed in this way: the length of the pipe to be ft., fill and well ram this pipe solid with sand ft. up, then have ready a metal-pot of very hot sand to fill the pipe one foot up, next fill the pipe up with more cold sand, ramming it as firmly as possible, stop the end and work it round as you did the water bend, but do not strike it too hard in one place, or you will find it give way and require to be dummied out again, or if you cannot get the dent out with the dummy send a ball through (see "bending with balls"). bending with balls or bobbins. this style of work is much practiced on small pipes, such as in. to in., especially by london plumbers. method: suppose your pipe to be in., then you require your ball or bobbin about / in. less than the pipe, so that it will run through the pipe freely. now pull the pipe round until it just begins to flatten, as at fig. , put the ball into the pipe, and with some short pieces of wood (say, in. long by ½ in. diameter) force the ball through the dented part of the pipe, or you may use several different-sized balls, as at a b c, fig. , and ram them through the pipe with a short mandrel, as at d m. you will require to proceed very carefully about this ramming, or otherwise you will most likely drive the bobbins through the back at l k j. you must also watch the throat part, g h i, to keep it from kinking or buckling-up; dress this part from the throat toward the back, in order to get rid of the surplus in the throat. [illustration: fig. .] three-ball or lead driving ball and double-ball bending. fig. shows a method of bending with three balls, one of lead being used as a driver attached to a piece of twine. this is a country method, and very good, because the two balls are kept constantly to the work. first, put the two balls just where you require the bend, then pull the pipe slightly round; take the leaden ball and drop it on the ball, b, then turn the pipe the other end up and drop it on a, and do so until your bend is the required shape. you must be careful not to let your leaden ball touch the back of the pipe. some use a piece of smaller leaden pipe run full of lead for the ball, c, and i do not think it at all a bad method, as you can get a much greater weight for giving the desired blow to your _boxwood_ balls. [illustration: fig. .] bending with windlass and brass ball. this is an excellent method of bending small pipes. fig. will almost describe itself. a is a brass or gun metal ball having a copper or wire rope running through it, and pulled through the flattened part of the pipe as shown. it will be quite as well to tack the bend down to the bench, as at b, when pulling the ball through; well dress the lead from front to back to thicken the back. i have seen some plumbers put an extra thickness of lead on the back before beginning to bend. notice: nearly all solid pressed pipes are thicker on one side than the other (as before remarked), always place the thickest part at the back. [illustration: fig. .] hydraulic or cup-leather and ball bending. fig . this is my own method of pipe-bending, and is very useful when properly handled with plenty of force, but requires great care and practice. you must have a union sweated on the end, a, fig. , and the ball, b, to fit the pipe. the cup-leather, e, should have a plate fixed on the front to press the ball forward. pull up the pipe as you please, and pump the ball through; it will take all the dents out, and that too very quickly. [illustration: fig. .] bending by splitting or split-made bends. this method of bending is much practiced in the provinces, and, for anything i know to the contrary, is one of the best methods in use, as by it you are likely to get a good substance of metal on the back of the bend whether the plumber be a good or a bad workman. proceed as follows: cut the pipe down the center to suit the length of your bend, as shown at a b, fig. . it will be quite as well if you first set out this bend on the bench, then you may measure round the back, as from c to l, to obtain the distance of the cut, which should always be three or four inches longer than the bend. you may also in this way obtain the correct length for the throat, g h i; here you will see that you have a quantity of lead to spare, i.e., from a to e, all of which has to be got rid of in uncut bends--some plumbers shift from front to back, but how many? not one in twenty. after you have cut the pipe, open the throat part, bend out the sides, and pull this part round a little at a time, then with a dummy, fig. , work the internal part of the throat outward to as nearly the shape as you can. go carefully to work, and do not attempt to work up the sides, a d b, until your throat is nearly to the proper shape, after which you may do so with a small boxwood dresser or bossing-stick (it is not necessary to explain minutely what a bosser or dressing-stick is, as they can be bought at almost any lead-merchants--the dresser is shown at e, fig. ; the bossing-stick is somewhat similar, the only difference being that it has a rounded face instead of flat.) keep the dummy up against the sides when truing it. if you have proceeded properly with this throat part, you will not require to work up the sides or edges, as in working the throat back the sides will come up by themselves. next take the back, pull it round a little at a time, the dummy being held inside, with your dresser work the two edges and sides slowly round, and the back will follow. never strike the back from the underside with the dummy. after you have made a dozen or two you will be able to make them as fast as you please, but do not hurry them at first, as the greater part of this work is only to be learned by patient application, perseverance, and practice. [illustration: fig. .] after you have made the bend it will require to be soldered, but before you can do this you must have the joint quite perfect and the edges true one with the other. a good bender will not require to touch his edges at all, but a novice will have to rasp and trim them up so that they come together. having your edges true, soil them, take a gauge-hook, which may be described as a shave-hook with a gauge attached, and shave it about / in. each side; now solder it to look like the solder a, fig. , which is done as follows: with some fine solder tack the joint at a d b, fig. , put on some resin, and with a well-heated copper-bit drop some solder roughly on the point from b to a, then draw the bit over it again to float the solder, being especially careful not to let the joint open when coming off at a. some plumbers think fit to begin here, but that is a matter of no importance. do not forget that if your joint is not properly prepared, that is to say, true and even, it is sure to be a failure, and will have a "higgledy-piggledy" appearance. some difference of opinion exists as to the best method of making these joints: one workman will make a good joint by drawing it while, on the other hand, another one will do it equally well by wiping it. drawing will be fully explained in a part on pipe making. it may, however, be here mentioned that it is a method of making the joint by floating the solder along the joint with the ladle and plumbing-iron. [illustration: fig. .] it is not uncommon for plumbers to make their bends with only one joint on the back. pulling up bends. in london, it is the favorite plan to make bends without cutting them. fig. . it is done by taking a length of pipe, and, just where you require the bend, lay it (_with the seam at the side_) upon a pillow, made by tightly filling a sack with sand, wood shavings, or sawdust; have some shavings ready to hand and a good lath, also a short length of mandrel about ft. long and about ½ in. smaller than the pipe, and a dummy as shown at a b, fig. . now, all being ready, put a few burning shavings into the throat of the bend, just to get heat enough to make it fizz, which you can judge by spitting on it. when this heat is acquired withdraw the fire, and let the laborer quickly place the end of the mandrel into the pipe, and pull the pipe up while you place a sack or anything else convenient across the throat of the bend, then pull the pipe up a little, just sufficient to dent it across the throat. now, with a _hot_ dummy, dummy out the dent, until it is round like the other part of the pipe. keep at this until your bend is made, occasionally turning the pipe or its side and giving it a sharp blow on the side with the soft or hornbeam dresser; this is when the sides run out as in fig. . never strike the back part of the bend from inside with the dummy, but work the lead from the throat to the back with a view to thickening the back. [illustration: fig. .] set-offs. a set-off is nothing more than a double bend, as shown at fig. , and made in much the same manner. d is the long end of the pipe. always make this bend first and pull it up quite square, as it will be found to go a little back when pulling up the other bend; if you can make the two together so much the better, as you can then work the stuff from the throat of one bend into the back of the other. the different shaped dummies are also here shown: f a round-nosed dummy, g a double bent dummy, h a single bent, i straight, j hand-dummy, abn a long bent dummy shown at fig. . [illustration: fig. .] bad bends. these can always be detected by examining them in their backs, as at fig. ; take a small dresser and tap the pipe a few times round abd to test for the thickness. strike it hard enough to just dent it; next strike the back part of the pipe, e, _with the same force_, and if it dents much more it is not an equally-made bend. i have seen some of these much-praised london-made bends that could be easily squeezed together by the pressure of the thumb and finger. n.b.--care must be taken not to reduce or enlarge the size of the bore at the bend. [illustration: fig. .] bad falls in bends. the fall given in bending lead pipes should be considered of quite as much importance as making the bends of equal thickness especially for pipes, as shown in fig. . in this fig. you have a drawing of a bad bend. from a to b there is no fall whatever, as also from b to c; such bending is frequently done and fixed in and about london, which is not only more work for the plumber, but next to useless for soil-pipes. fig. shows how this bend should be made with a good fall from a to j, also from m to n; the method of making these bends requires no further explanation. r, p, and k are the turnpins for opening the ends, the method of which will be explained in a future paragraph on "preparing for fixing." [illustration: fig. .] [illustration: fig. .] bends made into traps or retarders. it will sometimes be found requisite to retard the flow of water when running through soil or other pipes, or to direct it to another course, or even to form a trap in the length of pipe. this has been done in many ways, but figs. and represent the method that i, after mature consideration, think most preferable. there is nothing new about this style of bending, as it has been long in vogue with provincial plumbers, but more especially in kent. for many years it has had a run as a sink and slop closet-trap. mr. baldwin latham, in his "sanitary engineering," says it was introduced and has been used for the surrey and kent sewers from about . [illustration: fig. .] [illustration: fig. .] i have also noticed many of these traps in the sanitary exhibition at south kensington, made by graham and fleming, plumbers, who deserve a medal for their perseverance and skill, not only for the excellence of their bends, but also for some other branches of the trade, such as joint-wiping, etc., which is unquestionably the best work sent into this exhibition--in fact, quite equal to that which was shown at the exhibition of . i shall treat further of these bends in an article on fixing, in a future part. bends made with the "snarling dummy." this is an american method of making lead bends. fig. shows a dummy made upon a bent steel rod, fixed into the bench. the method of working it is by first pulling up the bend, and to get out the dents, strike the rod of the snarling dummy, as shown at a, and the reaction gives a blow within the bend, throwing out the bend to any shape required. this method of working the dummy is also taken advantage of in working up embossed vases, etc. [illustration: fig. .] _(to be continued)_ * * * * * the grossenhain shuttle-driver. the manufacture of fabrics having woofs of different colors requires the use of several shuttles and boxes containing the different colors at the extremity of the driver's travel, in which these boxes are adjusted alternately either by a rectilinear motion, or by a rotary one when the boxes are arranged upon a cylinder. the controlling mechanism of the shuttles by means of draught and tie machines constitutes, at present, the most perfect apparatus of this nature, because they allow of a choice of any shuttles whatever. [illustration: the grossenhain shuttle-driver.] the apparatus constructed by the grossenhainer webstuhl und maschinen fabrik, of grossenhain, and represented in the accompanying cut, is new as regards its general arrangement, although in its details it more or less resembles the analogous machines of schönherr, crompton, and hartmann. the lifting of the shuttles is effected by two sectors, a , a , arranged on the two sides of the loom, and the rotary motion of which acts upon the box, c, by means of the lever, b, the box being caused to descend again by the spring, d. parallel with the breast beam there is mounted an axle, e, and upon one of the extremities of this is fixed the sector, a , while the other extremity carries two fixed disks, f , f , two loose disks, f , f , and the sector, a , which is connected with the latter. the disks are kept in position by a brake, g. the pawls, h and h , are supported on a lever, i, on a level with the disks, and are connected with the cam, l, by the spring, k. this cam revolves with the axle of the loom and thrusts the pawls against the disk. a draught and tie machine controls the action of the pawls on the disks in such a way that, by the revolution of the sectors, a and a , the shuttle-boxes, i., ii., iii., are brought at the desired moment in the way of the driver. the pawls, h, are connected by wires with the bent levers, m, of the draught machine, which carry also the pawls, n. the upper position of the pawls, h, is limited by the direct resting of the levers, m, on the tappet, o, and the lower position by the resting of the pawls, n. the plates, p, held by the pattern, m, are set in motion horizontally by means of the eccentric, q, the crank, r, and the bent lever, s. the raised plates abut against the corresponding levers, m, and thus bring about the descent of the pawls, h, which are suspended from these levers. this position is maintained by the resting of the pawls, n, upon the tappet, o, until the lowering of the corresponding plate has set the pawl, n, free. the lever, m, then gives way to the action of the spring, t, and the pawl, h, rises again. the rotation of the cylinder which supports the design, m, is effected by the motion of the bent lever, s. * * * * * industrial art for women--carpet designing. a meeting of ladies was held in this city recently to consider the possibilities of industrial art in furnishing occupation for women. mrs. florence e. cory, principal of the woman's institute of technical design, which was recently established in this city, advanced the proposition that whatever could be done by man in decorative art could be done as well by women, and she made an earnest plea to her own sex to fit themselves by proper training to engage in remunerative industrial work. mrs. cory enjoys the distinction of being the first woman who ever attempted to make designs for carpets in this country. she said that four years ago, when she came to this city, there was no school at which was taught any kind of design as applied to industrial purposes, except at cooper union, where design was taught theoretically but not practically. during the past year or two, however, in many branches of industrial design women have been pressing to the front, and last year eighteen ladies were graduated from the boston institute of technology. most of these ladies are now working as designers for various manufacturers, eight are in print factories, designing for chintz and calico, two have become designers for oil-cloths, one is designing for a carpet company, and one for a china factory. carpet designing, said mrs. cory, is especially fitted for women's work. it opens a wide field to them that is light, pleasant, and remunerative. the demand for good carpet designs far exceeds the supply, and american manufactures are sending to europe, particularly england and france, for hundreds of thousands of dollars' worth of designs yearly. if the same quality of designs could be made in this country the manufacturers would gladly patronize home talent. one carpet firm alone pays $ , a year for its designing department, and of this sum several thousands of dollars go to foreign markets. more technical knowledge is required for carpet designing than for any other industrial design. it is necessary to have a fair knowledge of the looms, runnings of color, and manner of weaving. hitherto this knowledge has been very difficult, if not impossible, for women to obtain. but now there are a few places where competent instruction in this branch of industrial art is given. there are several kinds of work connected with this business that may be done at home by those who wish, and at very fair prices. the price of copying an ingrain design is from $ to $ per sheet. the price for an original design of the same size is from $ to $ . for brussels or tapestry sketches, which may be made at home, provided they are as good as the average sketch, the artists receive from $ to $ . for moquettes, axminsters, and the higher grades of carpets some artists are paid as high as $ . the average price, however, is from $ to $ . these designs may all be made at home, carried to the manufacturer, submitted to his judgment, and if approved, will be purchased. after the purchase, if the manufacturer desires the artist to put the design upon the lines and the artist chooses to do so, the work may still be done at home, and the pay will range from $ to $ extra for each design so finished. the average length of time for making a design is, for ingrains, two per week; brussels sketch, three per week; brussels on the lines, one in two weeks; moquettes and axminsters, one in two or three weeks, depending of course upon the elaborateness and size of the pattern. when the work is done at the designing-rooms, and the artist is required to give his or her time from o'clock in the morning until in the afternoon, the salaries run about as follows: for a good original ingrain designer, from $ , to $ , per year. a good brussels and tapestry designer from $ , to $ , per year. copyists and shaders, from $ to $ per week. mrs. r.a. morse advocated the establishment of schools of industrial art, in which there would be special departments so that young girls might be trained to follow some practical calling. mrs. dr. french said that unskilled labor and incompetent workmen were the bane and disgrace of this country, and she thought that the field of industrial art was very inviting to women. she disparaged the custom of decorating chinaware and little fancy articles, and said that if the time thus wasted by women was applied to the study of practical designing those who persevered in the latter branch of industrial art might earn liberal wages. miss requa, of the public school department, explained that elementary lessons in drawing were taught in the public schools. mme. roch, who is thoroughly familiar with industrial and high art in both this country and in europe, said that if the american people would apply themselves more carefully to the study of designing they could easily produce as good work as came from abroad. the beauties to be seen in american nature alone surpassed anything that she had ever witnessed in the old countries. * * * * * photography upon canvas. one of the most extensive establishments for the purpose is that of messrs. winter, in vienna. they say to photographers in general: if you will send us a portrait, either negative or positive, we will produce you an enlargement on canvas worked up in monochrome. the success of their undertaking lies in the circumstance that they do not produce colored work--or, at any rate, it is exceptional on their part to do so--but devote their efforts to the production of an artistic portrait in brown or sepia. in this way they can make full use of the dark brown photograph itself; there is less necessity for tampering with the enlarged image, and natural blemishes in the model itself maybe softened and modified, without interfering much with the true lines of face and features. the monotone enlargements of messrs. winter, again, exquisitely as most of them are finished, do not appear to provoke the opposition of the painter; they do not cross his path, and hence he is more willing to do them justice. many a would-be purchaser has been frightened out of his intention to buy an enlargement by the scornful utterance of an artist friend about "painted photographs," and in these days of cheap club portraits there is certainly much risk of good work falling into disrepute. but a well-finished portrait in monotone disarms the painter, and he is willing to concede that the picture has merit. "we cannot use english canvas, or 'shirting,' as you call it," said one of our hosts; "it seems to contain so much fatty matter." the german material, on the other hand, would appear to be fit for photography as soon as it had been thoroughly worked in hot water and rinsed. here, in this apartment, paved with red brick, we see several pieces of canvas drying. it is a large room, very clean, here and there a washing trough, and in one corner two or three large horizontal baths. the appearance is that of a wash-house, except that all the assistants are men, and not washerwomen; there is plenty of water everywhere, and the floor is well drained to allow of its running off. we are to be favored with a sight of the whole process, and this is the first operation. into one of the horizontal baths, measuring about by feet, is put the salting solution. it is a bath that can be rocked, or inclined in any direction, for its center rests upon a ball-and-socket joint. it is of _papier mâché_, the inside covered with white enamel. formerly, only bromine salts were employed, but now the following formula is adopted: bromide of potassium................... parts. iodide of potassium.................... part. bromide of cadmium..................... " water................................ parts. four assistants are required in the operation, and the same number when it comes to sensitizing and developing, all of which processes are commenced in the same way. the bath is tilted so that the liquid collects at one end, and near this end two assistants hold across the bath a stout glass rod; then the canvas is dipped into the liquid, and drawn out by two other assistants over the glass rod. in this way the canvas is thoroughly saturated, and, at the same time, drained of superfluous liquid. the canvas is hung up to dry; but as sometime must elapse before this particular piece will be ready for sensitizing, we proceed with another canvas which is fit and proper for that process. the room, we should have mentioned, is provided with windows of yellow glass; but as there is plenty of light nevertheless, the fact hardly strikes one on entering. the sensitizing, with a solution of nitrate of silver, is conducted with a glass rod in the same way as before, the solution being thus compounded: nitrate of silver........................ parts. citric acid.............................. part. water.................................. parts. again the canvas is dried, and then comes its exposure. this is done in a room adjoining. we lift a curtain and enter a space that reminds one of the underground regions of a theater. there are curtained partitions and wooden structures on every hand; dark murky corners combined with brilliant illumination. messrs. winter use the electric light for enlarging, a lamp of siemens' driven by a six-horse power engine. the lamp is outside the enlarging room, and three large lenses, or condensers, on three sides of the light, permit the making of three enlargements at one end at the same time. (see fig.) [illustration] the condenser collects the rays, and these shine into a camera arrangement in which the small negative is contained. the enlarged image is then projected, magic lantern fashion, upon the screen, to which is fastened the sensitized canvas. the screen in question is upon a tramway--there are three tramways and three screens in all, as shown in our sketch--and for this reason it is easy to advance and retire the canvas, for the purpose of properly focusing it. even with the electric light now employed, it is necessary to expose a considerable time to secure a vigorous impression. from ten minutes to half an hour is the usual period, determined by the assistant, whose experienced eye is the only guide. we should estimate the distance of the cameras from the enlarging apparatus to be about fourteen or fifteen feet in the instance we saw, and when the canvas was taken down, a distinct outline of the image was visible on its surface. by the way, we ought to mention that the canvas is in a decidedly limp state during these operations. it has just sufficient stiffness to keep smooth on the screen, and that is all; the treatment it has received appears to have imparted no increase of substance to it. again it is brought into the red-brick washing apartment, and again treated in one of the white enameled baths as before. this time it is the developer that is contained in the bath, and the small limp tablecloth--for that is what it looks like--after being drawn over the glass rod, is put back into the bath, and the developing solution rocked to and fro over it. the whiteness of the bath lining assists one in forming a judgment of the image as it now gradually develops and grows stronger. here is the formula of the developer: pyrogallic acid......................... parts. citric acid............................. " water................................... " the developer--which, it will be noted, is very acid--is warmed before it is used, say to a temperature of ° to ° c.; nevertheless, the development does not proceed very quickly. as we watched, exactly eight minutes elapsed before mr. winter cried out sharply, "that will do." immediately one of the assistants seizes the wet canvas, crumples it up without more ado, as if it were dirty linen, and takes it off to a wooden washing trough, where it is kneaded and washed in true washerwoman fashion. water in plenty is sluiced over it, and after more vigorous manipulation still, it is passed from trough to trough until deemed sufficiently free from soluble salts to tone. the toning--done in the ordinary way with gold--removes any unpleasant redness the picture possesses, and then follows the fixing operation in hyposulphite. as canvas is more permeable than paper, these two last processes are quickly got through. the final washing of the canvas is very thorough. again it is treated with all the vigor with which a good laundry-maid attacks dirty linen, the canvas, in the end, being consigned to a regular washing-machine, in which it is systematically worked for some time. when the canvas picture at last is finished, it presents a very rough appearance, by reason of the tiny fibers that stand erect all over the surface. to lay these, and also to improve the surface generally, the canvas is waxed, the fabric is stretched, and a semi-fluid mass rubbed into it, heat being used in the process, which not only gives brilliancy, but seems also to impart transparency to the shadows of the picture. the result is a pleasant finish, without vulgar glare or glaze, the high lights remaining beautifully pure and white. of course, the price of these canvas enlargements varies with the amount of artistic work subsequently put upon them; but the usual charge made by messrs. winter for a well-finished life-size portrait, three quarter length, is sixty florins, or about £ sterling as the exchange now stands. besides working for photographers, messrs. winter are reproducing a large number of classic paintings and cartoons by photography on canvas in this way (some of them almost absolutely untouched), and these, as may be supposed, are finding a very large sale among dealers. such copies must necessarily be of considerable value to artists and collectors, and altogether it would seem that messrs. winter have hit upon a novel undertaking, which bids fair to make them a handsome return for the outlay (large as it undoubtedly has been) made upon their vienna establishment.--_photo. news._ * * * * * detection of starch sugar sirup mixed with sugar-house molasses.[ ] [footnote : a paper read before the american chemical society, september , .] by p. casamajor. in previous communications i have given processes for detecting the adulteration of cane-sugar by starch-sugar. the adulteration of sugar-house sirups by starch glucose is still more extensively practiced than that of sugar, and a great portion of sirups sold by retailers in this market is adulterated with starch glucose. this form of adulteration may be very easily detected by the use of strong methylic alcohol, in which the alcoholometer of tralles or of gay lussac will indicate about ½°. a straight sugar-house sirup when mixed with three times its volume of this strong methylic alcohol will dissolve by stirring, giving a very slight turbidity, which remains suspended; while sirups containing the usual admixture of starch sugar give a very turbid liquid, which separates, when left at rest, into two layers, the lower being a thick viscous deposit containing the glucose sirup. considerable quantities are sold of a thin sirup, of about ° baumé, in which the proportion of sugar to the impurities is greater than in common sugar-house molasses. when a sirup of this kind is stirred with three times its volume of methylic alcohol, a marked turbidity and deposition will take place, which consists of pure sugar. the crystals are hard and gritty. they adhere to the sides of the glass, and are deposited on the bottom. there is no resemblance between this precipitate and that due to starch sugar sirup. it may not be useless to mention that if a straight sugar-house sirup of about ° b. density is stirred with three times its volume of _ethylic_ alcohol of about ½° the sirup will not dissolve. hence ethylic alcohol of this strength is not suitable for distinguishing a sirup mixed with starch glucose from a _straight_ sugar-house sirup. the presence of starch glucose in sugar-house molasses may be easily detected by the optical saccharometer when the sirup has the usual density of about ° b., and when starch sugar has been added in the usual quantities. for making the test the usual weight should be taken ( . grammes for duboscq's saccharometer, and . grammes for ventzke's instrument). the direct test should show a percentage of sugar not higher than the number of baumé degrees indicating the density, and it may be from to per cent. lower. to understand this, we must refer to the composition of cane-sugar molasses of ° b.: sugar....................................... . insoluble impurities........................ . water....................................... if the direct test should indicate per cent. of sugar, and if the molasses were straight, the composition would be-- sugar........................................... soluble impurities.............................. water........................................... now, a product of this composition would not be a clear sirup at ° b., but a mixture of sirup and crystals. therefore, if the product is a clear sirup at ° b., and it tests per cent., it cannot be _straight_. the presence of starch glucose in sugar-house molasses may also be detected by the copper test. the possibility of applying this test, as well as those already indicated, rests on the fact that starch glucose is always added in very large quantities for the purposes of adulteration. a very small addition could not be satisfactorily detected. the detection by the copper test rests on the observation that very nearly one-half of the soluble impurities in sugar-house molasses consists of glucose in the shape of inverted sugar. we have seen above that for a molasses of ° b. the soluble impurities amount to about ½ per cent. we may, then, lay down the rule: that the percentage of glucose shown by the copper test cannot, in a straight sugar-house molasses, be much greater than one-half of the number expressing the density in baumé degrees. the reason is obvious from what has been said of the test by the optical saccharometer. * * * * * false vermilion.--a curious case has been noticed in germany, where a small cargo of vermilion was purchased, and, upon being analyzed, turned out to be red oxide of lead colored by eosine. this is an entirely novel sophistication. the eosine was separated from the oxide of lead by digesting the product for twenty-four hours in very strong alcohol. a much shorter time is sufficient to color the spirit enough to enable an expert chemist to detect the presence of this splendid organic coloring matter. another kind of "vermilion" consists entirely of peroxide of iron, prepared especially to imitate the brilliant and costly sulphide of mercury, which it does very well, and is largely used in england, france, and america. * * * * * the position of manganese in modern industry. by m.v. deshayes. no body among the metals and the metalloids (silicium, titanium, tungsten, chromium, phosphorus, etc.) has occupied a more prominent position in modern metallurgy than _manganese_, and it is chiefly due to its great affinity for oxygen. when this substance was discovered, more than a century ago ( ), by the celebrated swedish chemist and mineralogist, gahn, by treating the black oxide of manganese in the crucible, no one would have thought that the new element, so delicate by itself, without any direct industrial use, would become, in the middle of the nineteenth century, one of the most powerful and necessary instruments for the success of the bessemer process, as well for its deoxidizing properties as for the qualities which it imparts to steel, increasing its resistance, its durability, and its elasticity, as has been shown elsewhere. without entering into a complete history (for it is beyond the task which we have here assumed),[ ] it will not be without interest to recall how, when manganese was first obtained in a pure state, that it was supposed that it would remain simply an object of curiosity in the laboratory; but when its presence was proved in spiegeleisen and when it came to be considered an essential ingredient in the best german and english works for cutlery steel (where it is thrown into the crucible as the peroxide), then we find that its qualities become better and better appreciated; and it is surprising that no technologist ever devoted his attention to the production of manganese alloys. [footnote : see _engineering_, may , ] it was not till after the investigations of dr. percy, tamm, prieger, and bessemer, who employed crucibles for the production of these alloys, that hendersen received the idea of utilizing it in the siemens furnace. so important a compound could not remain unemployed. the works at terre noire produced, by the martin furnace, for a number of years, ferro-manganese of to per cent. shortly afterward, when competition in the market was established, the works at carniola and at carinthia, some english factories, and more especially the works at saint-louis, near marseilles, of terre noire, of montluçon, etc., successfully adopted the manufacture of _ferro-manganese with the blast furnace_, which is without doubt the method best adapted for the reduction of metallic oxides, as well in consideration of the reactions as from an economical point of view. before very long it was possible to produce, by the blast furnace, alloys of , , , and even per cent., in using the hot air apparatus of siemens, cowper, and witwell, with the employment of good coke, and principally by calculating the charges for the fusion in such a manner as to obtain an extra basic and refractory slag. following in the same path, the phoenix co., of ruhrort, sent, in , to the metallurgical exposition of dusseldorf, samples of ferro-manganese obtained in a blast furnace, with an extra basic slag in which the silica was almost entirely replaced by alumina. the works of l'esperance, at oberhausen, exhibited similar products, quite pure as to sulphur and phosphorus, and they had a double interest at the exhibition, in consideration of the agitation over the thomas and gilchrist process (see the discussions which were raised at the meeting of the iron and steel institute). this process unfortunately requires for its prompt success the use of a very large quantity of spiegel or of ferro-manganese, in order to sufficiently carburize and deoxidize the burnt iron, which is the final product of the blowing. the production of ferro-manganese by the blast furnace depends upon the following conditions. . a high temperature. . on a proper mixture of the iron ores and the manganese. . on the production of slag rich in bases. these different conditions may be obtained with but slight variations at the different works, but the condition of a high temperature is one of the most important considerations, not only for the alloys of manganese, but equally as well for the alloys of iron, manganese, silicium, those of chromium, of tungsten, etc. it is also necessary to study the effects produced either in the crucible or in the blast furnace, and to examine the ores which for a long while have been regarded as not reducible. the works of terre noire especially made at the same time, in the blast furnace, ferro-silicon with manganese, alloys which are daily becoming more important for the manufacture of steels tempered soft and half soft without blowing. these alloys, rich in silicon, present the peculiarity of being poor in carbon, the amount of this latter element varying with the proportions of manganese. in addition to the alloys used in the iron and steel industry, we shall proceed to relate the recent progress obtained in the metallurgy of other materials (especially copper) by the use of _cupro-manganese_: +---+---------+-------+---------+---------+------+------------------------------ | | mn. | c. | si. | s. | p. | | |per cent.| | | | | +---+---------+-------+---------+---------+------+ | a | to | to | to | traces | |extra quality for soft metals. | b | to | . | to | scarcely|about |} medium quality | c | to | . | to | percep- | . .|} | d | to | . | to | tible. | |ordinary for hard metals. +---+---------+-------+---------+---------+------+------------------------------ the first alloys of manganese and copper were made in , by von gersdorff; soon after prof. schrötter of vienna made compounds containing or per cent. of manganese by reducing in a crucible the oxides of copper and manganese mixed with wood charcoal and exposing to a high heat. these alloys were quite ductile, very hard, very tenacious, and capable of receiving a beautiful polish; their color varies from white to rose color, according to the respective proportions of the two bodies; they are particularly interesting on account of the results which were obtained by adding them to certain metallic fusions. it is well known that in the fining of copper by oxidation there is left in the fined metal the suboxide of copper, which must then be removed by the refining process, using carbon to reduce the copper to its metallic state. m. manhès, taking advantage of the greater affinity of manganese for oxygen, found that if this last element was introduced into the bath of copper during the operation of refining, the copper suboxide would be reduced and the copper obtained in its metallic condition. for this purpose during these last years real cupro-manganese has been prepared, occupying the same position to copper as the spiegel or the ferro-manganese does toward the manufacture of steel. m. manhès used these same alloys for the fusion of bronze and brass, and recommended the following proportions: to kilog. of cupro-manganese for kilog. of bronze. . to do. do. do. brass. . to . do. do. do. copper. in every case the alloy is introduced at the moment of pouring, as is the case in the bessemer or martin process, taking care to cover the fusion with charcoal in order to prevent the contact with air, together with the use of some kind of a flux to aid in the scorification of the manganese. according to m. manhès a slight proportion of manganese added to bronze appears to increase its resistance and its ductility, as is shown in the following table, provided, however, that these different alloys have been subjected to the same operations from a physical point of view; that is, pouring, rolling, etc. --------------------------+-----+-----+------+----------+------------+ | | | | weight | | | cu. | sn. | mn. | of | elongation | | | | | fracture | | --------------------------+-----+-----+------+----------+------------+ ordinary bronze | | | | kil. | . | bronze with manganese, a, | | | . | " | . | do. do. b, | | | . | " | . | --------------------------+-----+-----+------+----------+------------+ the white brass co., of london, exhibited at paris, in , manganese bronzes of four grades of durability, destined for different uses and corresponding to about to kilos of the limit of elasticity, and to kilos of resistance to fracture; the number is equivalent after rolling to a resistance to fracture of . kilos, and to per cent. of elongation. such results show beyond contradiction the great interest there is in economically producing alloys of copper, manganese, tin, zinc, etc. in addition, they may be added to metallic fusions, for deoxidizing and also to communicate to the commercial alloys (such as bronze, brass, etc.) the greatest degree of resistance and tenacity. while many investigators have tried to form alloys of copper and manganese by combining them in the metallic state (that is to say, by the simultaneous reduction of their oxides), the hensler bros., of dillenburg, have found it best to first prepare the _metallic manganese_ and then to alloy it in proper proportions with other metals. their method consisted of reducing the pure pyrolusite in large plumbago crucibles, in the presence of carbon and an extra basic flux; the operation was carried on in a strong coke fire, and at the end of about six hours the _crude manganese_ is poured out, having the following composition: manganese to carbon to . iron . to . silicon . to . by refining, the manganese can be brought up to to per cent. of purity. it is from this casting of pure manganese that is obtained the substance used as a base for the alloys. this metal is white, crystalline, when exposed to the damp air slowly oxidizes, and readily combines with copper to form the _cupro-manganese_ of the variety having the composition-- copper manganese cast in ingots or in pigs it becomes an article of commerce which may be introduced in previously determined proportions into bronze, gun metal, bell metal, brass, etc. it may also be used, as we have already mentioned, for the refining of copper according to manhès's process. tests made from this standpoint at the works of mansfield have shown that the addition of . per cent. of cupro-manganese is sufficient to give tenacity to the copper, which, thus treated, will not contain more than . to . of oxygen, the excess passing off with the manganese into the scorias. on the other hand, the addition of cupro-manganese is recommended, when it is desirable to cast thin pieces of the metal, such as tubes, caldrons, kitchen utensils, which formerly could only be obtained by beating and stamping. the tenacity obtained for tubes of only three centimeters in diameter and . millimeters in thickness is such that they are able to withstand a pressure of , pounds to the square inch. the _manganese bronze_, which we have previously referred to, and which is used by the white brass company of london, is an alloy of copper, with from one to ten per cent. of manganese; the highest qualities of resistance, ductility, tenacity, and durability are obtained with one to four per cent. of manganese, while with twelve per cent. the metal becomes too weak for industrial uses. +-----------+---------+-----------+-------------+------------+ | manganese | | | weight of | | | bronze. | copper.| manganese.| fracture in | elongation.| | | | | kilos per | | | | | | square mm. | | +-----------+---------+-----------+-------------+------------+ | a | . | . | . | . | | b | . | . | . | . | | c | . | . | . | . | | d | . | . | . | . | +-----------+---------+-----------+-------------+------------+ the preceding table gives some of the experimental results obtained with the testing machine at friedrich-wilhelmshütte on the crude cast ingots; the resistance is increased, as with copper, by rolling or hammering. the _manganese german silver_ consists of copper................ . manganese............. . zinc.................. . but as this alloy often breaks in rolling, the preference is given to the following proportions: copper................ . manganese............. . zinc.................. . this results in a white, ductile metal, which is easily worked and susceptible of receiving a beautiful polish, like the alloys of nickel, which it may in time completely replace. the _bronzes of manganese, tin, and zinc_ were perhaps the first upon which important investigations were made; they were obtained by adding to an alloy of copper, zinc, and tin (ordinary bronze) a definite quantity of the cupro-manganese of the type indicated above (cu , mn ). by this means the resistance is increased fully nine per cent., probably in the same way as the copper, that is, by the deoxidizing effect of the manganese, as both the copper and the tin are always more or less oxidized in ordinary bronzes. manganese combines with tin just the same as it does with copper, and the proportion which is recommended as giving the highest resistances is three to six per cent. of cupro-manganese. however, notwithstanding the use of cupro-manganese, the tin, as in ordinary bronzes, has a tendency to liquate in those portions of the mould which are the hottest, and which become solid the last, especially in the case of moulds having a great width. from a series of experiments made at isabelle hütte, it has been found that the metal which has the greatest resisting qualities was obtained from copper...................... . manganese................... . zinc........................ . per cent. of cupro-manganese = manganese . remaining in the metal. the best method of procedure is first to melt the copper in a crucible, and then to add the tin and the zinc; finally the cupro-manganese is added just at the moment of pouring, as in the manhès process; then the reaction on the oxides is very effective, there is a boiling with scintillation similar to the action produced in the bessemer and martin process when ferro-manganese is added to the bath of steel. the following are some of the results obtained from thirteen alloys obtained in this manner. these samples were taken direct from the casting and were tested with the machine at friedrich-wilhelms-hütte, and with the one at the shops of the rhine railroad. their resistance was considerably increased, as with the other alloys, by rolling or hammering. -------+------+------+-----+---------+---------+----------+--------+-------+ | | | | | | | weight | | | | | | | |limit of | of | elong-| |nature| | | | |elasticity|fracture| ation,| | of | | | | cupro- |in kilos |in kilos| per- | numbers|mould.|copper| tin.| zinc. |manganese|per mm. | per mm.|centage| -------+------+------+-----+---------+---------+----------+--------+-------+ | sand | . | . | . | | . | . | -- | | -- | . | . | . | . | . | . | . | | cast.| . | . | . | . | -- | . | -- | | -- | . | . | . | . | -- | . | . | | -- | . | . | . | . | -- | . | . | | -- | . | . | . | . | -- | . | . | | sand | . | . | . | . | -- | . | . | | -- | . | . | . | . | -- | . | . | | -- | . | . | . | . | . | . | -- | | -- | . | . | . | . | . | . | -- | | | | |( . pb)| | | | | | -- | . | . | ( pb) | . | . | . | -- | | -- | . | . | . | . | . | . | -- | | -- | . | . | -- | . | . | . | -- | -------+------+------+-----+---------+---------+----------+--------+-------+ the results of the tests of ductility which are here given, with reference to the _cupro-manganese_, _manganese bronze_, the _alloys_ with _zinc_ and _tin_, are taken from m.c. hensler's very valuable communication to the berlin society for the advancement of the industrial arts. these various alloys, as well as the _phosphorus bronze_, of which we make no mention here, are at present very largely used in the manufacture of technical machines, as well as for supports, valves, stuffing-boxes, screws, bolts, etc., which require the properties of resistance and durability. they vastly surpass in these qualities the brass and like compounds which have been used hitherto for these purposes.--_bull. soc. chim., paris_, xxxvi. p. . * * * * * the economical washing of coal gas and smoke. in a recent number of the _journal des usines à gaz_ appears a note by m. chevalet, on the chemical and physical purification of gas, which was one of the papers submitted to the société technique de l'industrie du gaz en france at the last ordinary meeting. this communication is noticeable, apart from the author's conclusions, for the fact that the processes described were not designed originally for use in gas manufacture, but were first used to purify, or rather to remove the ammonia which is to be found in all factory chimneys, and especially in certain manufactories of bone-black, and in spirit distilleries. it is because of the success which attended m. chevalet's treatment of factory smoke that he turned his attention to coal gas. the communication in which m. chevalet's method is described deals first with chimney gases, in order to show the difficulties of the first class of work done by the author's process. like coal gas, chimney gases contain in suspension solid particles, such as soot and ashes. before washing these gases in a bath of sulphuric acid, in order to retain the ammonia, there were two problems to be solved. it was first of all necessary to cool the gases down to a point which should not exceed the boiling-point of the acid employed in washing; and then to remove the solid particles which would otherwise foul the acid. in carrying out this mechanical purification it was impossible, for two reasons, to make use of apparatus of the kind used in gas works; the first obstacle was the presence of solid particles carried forward by the gaseous currents, and the other difficulty was the volume of gas to be dealt with. in the example to which the author's attention was directed he had to purify cubic meters of chimney gas per minute, or , cubic meters per hour, while the gas escaped from the flues at a temperature of from ° to ° c. ( ° to ° fahr.), and a large quantity of cinders had frequently to be removed from the main chimney flues. after many trials a simple appliance was constructed which successfully cooled the gases and freed them from ashes. this consisted of a vertical screen, with bars three mm. apart, set in water. this screen divided the gases into thin sheets before traversing the water, and by thus washing and evaporating the water the gases were cooled, and threw down the soot and ashes, and these impurities fell to the bottom of the water bath. the gases after this process are divested of the greater part of any tarry impurities which they may have possessed, and are ready for the final purification, in which ammonia is extracted. this is effected by means of a series of shallow trays, covered with water or weak acid, and pierced with a number of fine holes, through which the gas is made to bubble. the washing apparatus is therefore strangely similar in principle to that designed by mr g. livesey. m. chevalet states that this double process is applicable to gas works as well as to the purification of smoke, with the difference that for the latter purpose the washing trays are filled with acid for the retention of ammonia, while in the former application gas liquor or water is used. the arrangement is said to be a practical success.--_journal of gas lighting._ * * * * * determination of nitrogen in hair, wool, dried blood, flesh meal, and leather scraps. by dr. c. krauch. differences obtained in the estimation of nitrogen in the above substances are frequently the source of much annoyance. the cause of these discrepancies is chiefly due to the lack of uniformity in the material, and from its not being in a sufficiently fine state during the combustion. the hair which is found in commerce for the manufacture of fertilizers, is generally mixed with sand and dust. wool dust often contains old buttons, pieces of wood, shoe pegs, and all sorts of things. the flesh fertilizers are composed of light particles of flesh mixed with the heavier bone dust. even after taking all possible precautions to finely comminute these substances by mechanical means, still only imperfect results are obtained, for the impurities, that is to say, the sand, can never be so intimately mixed with the lighter particles that a sample of . to . gramme, such as is used in the determination of nitrogen, will correspond to the correct average contents. in substances such as dried blood, pulverization is very tedious. a very good method of overcoming these difficulties, and of obtaining from the most mixed substances a perfectly homogeneous mass, is that recommended by grandeau[ ] of decomposing with sulphuric acid--a method which as yet does not seem to be generally known. from a large quantity of the substance to be examined, the coarse stones, etc., are removed by picking or sifting, and the prepared substance, or in cases where the impurities cannot be separated, the original substance, is treated with sulphuric acid; after it is decomposed, the acid is neutralized with calcium carbonate, and the nitrogen is determined in this mass. [footnote : _handbook d. agrict. chem. analyst._, p. .] in order to operate rapidly, it is best to use as little sulphuric acid as possible. if too much sulphuric acid is used, necessarily a large amount of calcium carbonate is essential to get it into proper condition for pulverizing. under such circumstances the percentage of nitrogen becomes very low, and a slight error will become correspondingly high. c.c. of concentrated sulphuric acid and c.c. are sufficient for to grammes of material. after the substance and liquid have been thoroughly stirred in a porcelain dish, they are warmed on a water bath and continually stirred until the mass forms a homogeneous liquid. the sirupy liquid thus obtained is then mixed with to grammes of pulverized calcium carbonate (calcspar), dried for fifteen minutes at to ° c., and after standing for one to two hours the dish and its contents are weighed. from the total weight the weight of the dish is subtracted, which gives the weight of the calcium sulphate and the calcium carbonate, and the known weight of the wool dust, etc. this material is then intimately ground, and to grammes of it are taken for the determination of the nitrogen, which is then calculated for the original substance. although the given quantities of water and sulphuric acid hardly appear sufficient for such a large quantity of hair or wool, still in the course of a few minutes to a quarter of an hour, after continual stirring, there is obtained a liquid which, after the addition of the calcium carbonate, is readily converted into a pulverized mass. frequently a smaller quantity of sulphuric acid will suffice, especially if the material is moist. the chief merit of this process is that in a short time a large quantity of material, having a uniform character, is obtained. its use is, therefore, recommended for general employment. when the coarser stones, etc., are weighed, and the purified portion decomposed, absolutely correct results are obtained, and in this way the awkward discrepancies from different analysts may be avoided.--_chemiker zeitung_, v. , p. . * * * * * testing white beeswax for ceresine and paraffins. by a. peltz. the method which is here recommended originated with dr. m. buchner, and consists in preparing a concentrated solution of alcoholic caustic potash--one part caustic potash to three of per cent. alcohol--and then boiling one to two grammes of the suspected wax in a small flask with the above solution. the liquid is poured into a glass cylinder to prevent solidification of the contents, and it is then placed for about one half hour in boiling water. with pure wax the solution remains clear white; when ceresine and paraffine are present, they will float on the surface of the alkali solution as an oily layer, and on cooling they will appear lighter in color than the saponified mass, and thus they may be quantitatively estimated. the author likewise gives a superficial method for the determination of the purity of beeswax. it depends on the formation of wax crystals when the fused wax solidifies. these crystals form on the surface on cooling, and are still visible after solidification when examining the surface from the side. the test succeeds best when the liquid wax is poured into a shallow tin mould after cooling another peculiar property of the wax becomes apparent. while the beeswax fills a smaller volume, that is, separates from the sides of the mould, the japanese wax, without separating from the sides, becomes covered with cracks on cooling which have a depth corresponding to the thickness of the wax.--_neuste erfindungen und erfahrungen_, viii., p. . * * * * * the prevention of alcoholic fermentation by fungi. by prof. e. reichard. the manager of a well directed brewery, which was built according to the latest improvements and provided with ice-cooling arrangements, found that the alcoholic fermentation of lager beer did not advance with proper regularity. the beer did not clarify well, it remained turbid and had a tendency to assume a disagreeable odor and taste. microscopic examination of the yeast, however, showed the same to be bottom yeast. after some time its action apparently diminished, or rather, the fermentation, which began well, ceased, and at the same time a white foam formed in the center of the vat. the manager observing this, again submitted it to microscopic examination. the instrument revealed a number of much smaller forms of fungi, similar to those of young yeast, and some which were excessively large, a variety never found in bottom yeast. fully appreciating the microscopic examination, and aware of the danger which the spread of the fungi could cause, the manager resorted to all known means to retard its pernicious influence. fresh yeast was employed, and the fermenting vats throughly cleaned, both inside and out, but the phenomena reappeared, showing that the transmission took place through the air. a microscopic examination of a gelatinous coating on the wall of the fermenting room further explained the matter. beginning at the door of the ice cellar, the walls were covered with a gelatinous mass, which, even when placed beneath the microscope, showed no definite organic structure; however it contained numerous threads of fungi. notwithstanding the precautions which were taken for cleanliness, these germs traveled from the ceiling through the air into the fermenting liquid and there produced a change, which would ultimately have caused the destruction of all the beer. for a third time and by altogether different means, it was demonstrated that the air was the bearer of these germs. the whole atmosphere was infected, and a simple change of air was by no manner of means sufficient, as has already been shown. in addition, these observations throw considerable light on the means by which contagious diseases are spread, for often a room, a house, or the entire neighborhood appears to be infected. it must also be remembered how, in times of plague, large fires were resorted as to a method of purifying the air. with the infinite distribution of germs, and as they are always present in all places where any organic portions of vegetable or animal matter are undergoing decomposition, it becomes, under certain circumstances, exceedingly difficult, and at times even impossible, to trace the direct effect of these minute germs. the organism is exposed to the destructive action of the most minute creation; several changes in this case give to them the direct effect of the acting germs. the investigation of the chemist does not extend beyond the chemical changes; nevertheless these phenomena are directly explained by the microscope, without which, in the present case, the discovery of the cause would have remained unknown.--_arch. der pharm._, , . * * * * * new reaction of glycerine. if two drops of phenic acid are diluted with three thousand to five thousand parts of water, a distinct blue color is produced by one drop of solution of perchloride of iron. the addition of six or eight drops of glycerine entirely removes the color, and if any glycerine was present in the liquid the reaction does not take place at all. by this test the presence of per cent. of glycerine can be detected. it may be applied to the analysis of wines, beers, etc., but when there is much sugar, extractive or coloring matter, the test can only be applied after evaporating, dissolving the residue in alcohol and ether, evaporating again, and then redissolving in water. alkaline solutions must be first acidulated.--_pharm. zeit. für russ._ * * * * * lycopodine. while the phanerogams or flowering plants annually contribute to the list of newly discovered alkaloids, with the exception of muscarine and amanitine, no alkaloid has as yet been definitely recognized among the cryptogams. karl bödeker, of göttingen, has opened the road in this direction, and gives in a paper sent to liebig's _annalen der chemie_, august , , the following account of an alkaloid, which, from the name of the plant in which it occurs, he calls lycopodine. the plant yielding the alkaloid, _lycopodium complanatum_, belongs to the group of angiospermous cryptogams. it is distributed throughout the whole of north and middle europe, and contains the largest proportion of aluminum of any known plant. its bitter taste led the author to suspect an alkaloid in it. to prepare the alkaloid the dried plant is chopped up and twice exhausted with boiling alcohol of per cent. the residue is squeezed out while hot, and the extract, after being allowed to settle awhile, is decanted off, and evaporated to a viscid consistency over a water bath. this is then repeatedly kneaded up with fresh quantities of lukewarm water until the washings cease to taste bitter, and to give a reddish brown coloration when treated with a strong aqueous solution of iodine. the several washings are collected and precipitated with basic lead acetate, the precipitate filtered off, and the lead in the filtrate removed by sulphureted hydrogen. the filtrate from the lead sulphide is evaporated down over a water bath, then made strongly alkaline with a solution of caustic soda, and repeatedly shaken up with fresh quantities of ether so long as the washings taste bitter and give a precipitate with iodine water. after distilling off the ether, the residue is treated with strong hydrochloric acid, the neutral or slightly acid solution filtered off from resinous particles, slowly evaporated to crystallization, and the crystals purified by repeated recrystallization. to prepare the pure base a very concentrated solution of this pure hydrochlorate is treated with an excess of a very concentrated solution of caustic soda, and pieces of caustic potash are added, whereupon the free alkaloid separates out at first as a colorless resinous stringy mass, which, however, upon standing, turns crystalline, forming monoclinic crystals similar to tartaric acid or glycocol. the crystals are rapidly washed with water, and dried between soft blotting paper. thus prepared, lycopodine has a composition which may be represented by the formula c_{ }h_{ }n_{ }o_{ }. it melts at ° to ° c. without loss of weight. it is tolerable soluble in water and in ether, and very soluble indeed in alcohol, chloroform, benzol, or amyl alcohol. lycopodine has a very pure bitter taste. the author has formed several salts of the base, all of a crystalline nature, and containing water of crystallization. the hydrochlorate gives up a part of its water of crystallization at the ordinary temperature under a desiccator over sulphuric acid, and the whole of it upon heating.--_chemist and druggist._ * * * * * conchinamine. some years ago, o. hesse, when preparing chinamine from the renewed bark of _cinchona succirubra_, found in the mother liquid a new alkaloid, which he then briefly designated as conchinamine. he has lately given his attention to the separation and preparation of this alkaloid, and gives in liebig's _annalen der chemie_, august , , the following description of it: _preparation._--the alcoholic mother lye from chinamine is evaporated down and protractedly exhausted with boiling ligroine, whereby conchinamine and a small quantity of certain amorphous bases are dissolved out. upon cooling the greater part of the amorphous bases precipitates out. the ligroine solution is then first treated with dilute acetic acid, and then with a dilute solution of caustic soda, whereupon a large quantity of a resinous precipitate is formed. this is kneaded up with lukewarm water to remove adherent soda, and then dissolved in hot alcohol. the alcoholic solution is saturated with nitric acid, which has been previously diluted with half its volume of water, and the whole set aside for a few days to crystallize. the crystals of conchinamine nitrate are purified by recrystallization from boiling water. on dissolving these pure crystals of the nitrate in hot alcohol of per cent., and adding ammonia, absolute pure conchinamine separates out on cooling. _composition._--conchinamine may be represented by the formula c_{ }h_{ }n_{ }o_{ }, without water of crystallization. _properties._--conchinamine is easily soluble in hot alcohol of per cent., and in ether and ligroine, from which solutions it crystallizes in quadrilateral shining prisms. it is extremely soluble in chloroform, but almost insoluble in water. it melts at ° c., forming crystalline stars on cooling. _salts._--the salts of conchinamine, like the base itself, have much in common with chinamine, but are, as a rule, more easily crystallizable. they are prepared by neutralizing an alcoholic solution of the base with the acid in question.--_chemist and druggist._ * * * * * chinoline. the valuable properties of which chinoline has been found to be possessed have led to its admission as a therapeutic agent, and the discoverer of these properties, jul. donath, of baja, in hungary, in a paper sent to the _berichte der deutschen chemischen gesellschaft_, september , , gives the following further details as to this interesting substance. _antiseptic properties._--chinoline appears to be an excellent antiseptic. the author found that grammes of a bucholze's solution for the propagation of bacteria, charged with . g. of chinoline hydrochlorate, had remained perfectly clear and free from bacteria after standing forty-six days exposed to the air, while a similar solution, placed under the same conditions, without chinoline, had turned muddy and contained bacteria after only twelve days' standing. _antizymotic properties._--chinoline, even in the proportion of per cent., does not prevent alcoholic fermentation, while in as small a quantity as . per cent. it does not prevent lactic acid fermentation. _physiological effects._--the author gave a healthy man during several days various doses of chinoline tartrate, which in no way affected the individual operated on, nor was any trace of chinoline found in his urine. the author, therefore, considers that the base is oxidized by the blood to carbopyridinic acid, which is a still more powerful antiseptic than chinoline itself. chinoline taken internally would, therefore, be a useful and safe agent in cases of internal putrid fungoid or other growth. _chemical reactions._--chinoline yields very characteristic reactions with a number of chemical reagents, for a description of which we refer to the original paper.--_chemist and druggist._ * * * * * preparation of coniine. dr. j. schorm, of vienna, the author of this paper, after remarking that in spite of the increase of the consumption of coniine, the methods hitherto in vogue for preparing it yielded an article which darkened on exposure to the air, and the salts of which crystallized but badly, gives the following method for preparing pure coniine and its salts: _preparation of crude coniine._ a.-- kilogrammes of hemlock seed are moistened with hot water, and after swelling up are treated with kilogrammes of sodium carbonate previously dissolved in the requisite quantity of water (caustic alkalies cannot be used). the swollen seed is worked up uniformly with shovels, and then placed in an apparatus of kilogrammes capacity, similar to that used in the distillation of ethereal oils, and charged with steam under a pressure of three atmospheres. coniine distills over with the steam, the greater part separating out in the receiver as an oily stratum, while a part remains dissolved in the water. the riper the seeds, the greater is the percentage yield of oily coniine, and the sooner is the distillation ended. the distillate is neutralized with hydrochloric acid, and the whole evaporated to a weak sirupy consistence. when cool, this sirup yields successive crops of sal-ammoniac crystals, which latter are removed by shaking up the mass with twice its volume of strong alcohol, and filtering. this filtrate is freed from alcohol by evaporation over a water bath, the approximate quantity of a solution of caustic soda then added, and the whole shaken up with ether. the ethereal solution is then cooled down to a low temperature, whereby it is separated from conhydrine, which, being somewhat difficultly soluble in ether, crystallizes out. b.--the bruised hemlock seed is treated in a vacuum extractor with water acidulated with acetic acid, and the extract evaporated in vacuo to a sirupy consistence. the sirup is treated with magnesia, and the coniine dissolved out by shaking up with ether. the b method yields a less percentage of coniine than a, but of a better quality. _rectification of the crude coniine._ the solution of crude coniine in ether obtained by either of the above processes is evaporated over a water bath to remove the ether, mixed with dry potassium carbonate, and then submitted to fractional distillation from an air bath. the portion distilling over at ° c. to ° c. is pure coniine, and represents per cent. of the crude coniine. coniine thus prepared is a colorless oily liquid, volatile at the ordinary temperature, and has a specific gravity of . . at a temperature of °c it absorbs water, which it gives up again upon heating. it is soluble in parts of water. it is not altered by light. the author has formed a number of salts from coniine thus prepared, and finds them all crystallizable and unaffected by light.--_berichte der deutschen chemischen gesellschaft._--_chem. and druggist._ * * * * * strontianite. since it has been shown by professor scheibler, of berlin, that strontium is the most powerful medium of extraction in sugar refining, owing to its capacity of combining with three parts of saccharate, the idea suggests itself that the same medium might be successfully employed in the arts, and form a most interesting subject of experiment for the chemist. hitherto native strontianite, that is, the to per cent. pure carbonate of strontium (not the celestine which frequently is mistaken by the term strontianite), has not been worked systematically in mines, but what used to be brought to the market was an inferior stone collected in various parts of germany, chiefly in westphalia, where it is found on the surface of the fields. little also has been collected in this manner, and necessarily the quality was subject to the greatest fluctuations. by dr. scheibler's important discovery, a new era has begun in the matter of strontianite. deposits of considerable importance have been opened in the westphalian districts at a very great depth, and the supply of several , tons per annum seems to be secured, whereas only a short time ago it was not thought possible that more than a few hundred tons could in all be provided.--_chemist and druggist._ * * * * * parangi--a newly described disease. a peculiar contagious disease, called framboesia, or the yaws, has long been known to exist in africa, the west indies, and the northern parts of the british islands. it is chronic in character, and is distinguished by the development of raspberry-like tumors of granulation tissue on different parts of the body. a disease of a somewhat similar, but severer type, has for many years prevailed in ceylon. even less was known of this affection than of its supposed congener, until a recent careful report upon the subject by mr. w.r. kinsey, principal civil medical officer of ceylon. the disease in question is called "parangi," and is defined by mr. kinsey (_british medical journal_) as a specific disease, produced by such causes as lead to debilitation of the system; propagated by contagion, generally through an abrasion or sore, but sometimes by simple contact with a sound surface; marked by an ill-defined period of incubation, followed by certain premonitory symptoms referable to the general system, then by the evolution of successive crops of a characteristic eruption, which pass on in weakly subjects into unhealthy and spreading ulcers whose cicatrices are very prone to contraction; running a definite course; attacking all ages, and amenable to appropriate treatment. the disease seems to develop especially in places where the water supply, which in ceylon is kept in tanks, is insufficient or poor. the bad food, dirty habits, and generally unhygienic mode of life of the people, help on the action of the disease. parangi, when once developed, spreads generally by contagion from the discharges of the eruptions and ulcers. the natural secretions do not convey the poison. the disease may be inherited also. in the clinical history of the disease there are, according to mr. kinsey, four stages. the first is that of incubation. it lasts from two weeks to two months. a sore will be found somewhere upon the body at this time, generally over some bony prominence. the second is the stage of invasion, and is characterized by the development of slight fever, malaise, dull pains in the joints. as this stage comes on the initial sore heals. this second stage lasts only from two to seven days, and ends with an eruption which ushers in the third stage. the eruption appears in successive crops, the first often showing itself on the face, the next on the body, and the last on the extremities. this eruptive stage of the disease continues for several weeks or months, and it ends either in convalescence or the onset of a train of sequelæ, which may prolong the disease for years. parangi may attack any one, though the poorly fed and housed are more susceptible. one attack seems to confer immunity from another. although some of the sequelæ of the disease are most painful, yet death does not often directly result from them, nor is parangi itself a fatal disease. persons who have had parangi and passed safely through it, are not left in impaired health at all, but often live to an old age. the similarity of the disease, in its clinical history, to syphilis, is striking. mr. kinsey, however, considers it, as we have stated, allied to, if not identical with framboesia.--_medical record._ * * * * * a castor oil substitute. so far back as , mr. alexander ure investigated the purgative properties of the oil of anda. the specimen with which the experiments were tried had not been freshly prepared, and had indeed been long regarded as a curiosity. twelve ounces were alone available, and it was a yellowish oil, quite bright, about the consistence of oleum olivæ, devoid of smell, and free from the viscid qualities of castor oil. there was a small supply of anda fruits differing a good deal in appearance one from the other, but we are not aware whether these were utilized and the oil expressed; as far as our recollection serves, the subject was abandoned. it was known that the natives of brazil used the seeds as an efficient purgative in doses of from one to three, and it was in contemplation to introduce this remedy into england, though it was by no means certain that under distinctly different climatic influences equally beneficial results might be expected. mr. ure determined, by actual experiment, to ascertain the value of the oil in his own hospital practice. he found that small doses were better than larger ones, and in several reported cases it appeared that twenty drops administered on sugar proved successful. oil of anda-açu, or assu, therefore, would stand mid-way between ol. ricini and ol. crotonis. these researches seem to have been limited to the original sample, although the results obtained would appear to justify a more extended trial. m. mello-oliveira. of rio janeiro, has endeavored to bring the remedy into notice under the name of "huile d'anda-assu," and possibly may not have been acquainted with the attempt to introduce it into english practice. he describes the anda as a fine tree (_johanesia princeps_, euphorbiaceæ), with numerous branches and persistent leaves, growing in different parts of brazil, and known under the name of "coco purgatif." the fruit is quadrangular, bilocular, with two kernels, which on analysis yield an active principle for which the name "johaneseine" is proposed. this is a substance sparingly soluble in water and alcohol, and insoluble in chloroform, benzine, ether, and bisulphide of carbon. evidence derived from experiments with the sulphate of this principle did not give uniform results: one opinion being that, contrary to the view of many brazilian physicians, this salt had no toxic effect on either men or animals. local medical testimony, however, was entirely in favor of the oil. dr. torrès, professor at rio janeiro, using a dose of two teaspoonfuls, had been successful. dr. tazenda had obtained excellent results, and dr. castro, with a somewhat larger dose ( ijss.), was even enthusiastic in its praise. it might, therefore, be desirable at a time when new remedies are so much in vogue, not to abandon altogether a brazilian medicament the value of which is confirmed both by popular native use and by professional treatment. m. mello-oliveira comes to the conclusion that oleum anda assu (or açu) may be employed wherever castor oil is indicated, and with these distinct advantages: first, that its dose is considerably less; secondly, that it is free from disagreeable odor and pungent taste; and thirdly, being sufficiently fluid, it is not adherent to the mouth so as to render it nauseous to the patient. in this short abstract the spelling of the french original has been retained. as this therapeutic agent claimed attention thirty years ago, and has again been deemed worthy of notice in scientific journals, some of our enterprising pharmacists might be inclined to add it to the list of their commercial ventures.--_chemist and druggist._ * * * * * household and other recipes. mr. jas. w. parkinson gives in a recent number of the _confectioner's journal_ the following useful recipes: christmas plum pudding. stone a pound of bloom raisins; wash and clean a pound of zante currants; mince finely a pound of beef suet; mix with this, in a large pan, a pound of stale bread crumbs and half a pound of sifted flour. beat together in another pan six eggs, and mix with them half a pint of milk. pour this over the suet and flour, and stir and beat the whole well together; then add the raisins, currants, and a seasoning of ground cinnamon, grated nutmeg, powdered ginger, and a little ground cloves, a teaspoonful of salt, one pound of sugar, and a glass of jamaica rum. this pudding may now be boiled in a floured cloth or in an ornamental mould tied up in a cloth. in either way it requires long and constant boiling, six hours at least for one such as the above. every pudding in a cloth should be boiled briskly, till finished, in plenty of water, in a large pot, so as to allow it to move about freely. to take the boiled pudding out of the cloth without breaking it, dip it into cold water for a minute or two, then place it in a round bottomed basin that will just hold it, untie the cloth and lay bare the pudding down to the edge of the basin; then place upon it, upside down, the dish on which it is to be served, and invert the whole so that the pudding may rest on the dish; lastly, lift off the basin and remove the cloth. the use of the cold water is to chill and solidify the surface, so that it may part from the cloth smoothly. plum pudding may also be baked in a mould or pan, which must be well buttered inside before pouring the pudding into it. two hours' boiling suffices. plum-pudding sauce. put into a saucepan two ounces of best butter and a tablespoonful of flour; mix these well together with a wooden spoon, and stir in half a pint of cold water and a little salt and pepper. set this on the fire and stir constantly till nearly boiling; then add half a tumbler of madeira wine, brandy, or jamaica rum, fine sugar to the taste, and a little ground cinnamon or grated nutmeg. make the sauce very hot, and serve over each portion of the pudding. national plum pudding. an excellent plum pudding is made as follows: half a pound of flour, half a pound of grated bread crumbs, a pound of zante currants, washed and picked; a pound of raisins, stoned; an ounce of mixed spices, such as cinnamon, mace, cloves, and nutmeg; an ounce of butter, two ounces of blanched almonds, cut small; six ounces of preserved citron and preserved orange peel, cut into small pieces; four eggs, a little salt, four ounces of fine sugar, and half a pint of brandy. mix all these well together, adding sufficient milk to bring the mixture to a proper consistency. boil in a floured cloth or mould for eight hours. the sauce for the above. into a gill of melted butter put an ounce of powdered sugar, a little grated nutmeg, two wine glasses of madeira wine and one of curacoa. stir all well together, make very hot, and pour it over the pudding. egg-nog, or auld man's milk. separate the whites and yolks of a dozen fresh eggs. put the yolks into a basin and beat them to a smooth cream with half a pound of finely pulverized sugar. into this stir half a pint of brandy, and the same quantity of jamaica rum; mix all well together and add three quarts of milk or cream, half a nutmeg (grated), and stir together. beat the whites of the eggs to a stiff froth; stir lightly into them two or three ounces of the finest sugar powder, add this to the mixture, and dust powdered cinnamon over the top. egg flip. beat up in a bowl half a dozen fresh eggs; add half a pound of pulverized sugar; stir well together, and pour in one quart or more of boiling water, about half a pint at a time, mixing well as you pour it in; when all is in, add two tumblers of best brandy and one of jamaica rum. roast turkey. the turkey is without doubt the most savory and finest flavored of all our domestic fowls, and is justly held in the highest estimation by the good livers in all countries where it is known. singe, draw, and truss the turkey in the same manner as other fowls; then fill with a stuffing made of bread crumbs, butter, sweet herbs rubbed fine, moistened with eggs and seasoned with pepper, salt, and grated nutmeg. sausage meat or a forced meat, made of boiled chicken meat, boiled ham grated fine, chopped oysters, roasted or boiled chestnuts rubbed fine, stewed mushrooms, or last but not the least in estimation, a dozen fine truffles cut into pieces and sauted in the best of butter, and added part to the stuffing and part to the sauce which is made from the drippings (made into a good brown gravy by the addition of a capful of cold water thickened with a little flour, with the giblets boiled and chopped fine in it). a turkey of ten pounds will require two and a half hours' roasting and frequent basting. currant jelly, cranberry jelly, or cranberry sauce should always be on the table with roast turkey. woodcocks and snipe. some epicures say that the woodcock should never be drawn, but that they should be fastened to a small bird spit, and should be put to roast before a clear fire; a slice of toast, put in a pan below each bird, in order to catch the trail; baste them with melted butter; lay the toast on a hot dish, and the birds on the toast. they require from fifteen to twenty minutes to roast. snipe are dressed in the same manner, but require less time to cook. my pet plan to cook woodcock is to draw the bird and split it down the back, and then to broil it, basting it with butter; chop up the intestines, season them with pepper and salt, and saute them on a frying pan with butter; lay the birds on toast upon a hot dish and pour the saute over them. canvas-back ducks. select young fat ducks; pick them nicely, singe, and draw them carefully without washing them so as to preserve the blood and consequently the full flavor of the bird; then truss it and place it on the spit before a brisk fire, or in a pan in a hot oven for at least fifteen or twenty minutes; then serve it hot with its own gravy, which is formed by its own blood and juices, on a hot dish. it may also be a little less cooked, and then carved and placed on a chafing dish with red currant jelly, port wine, and a little butter. pheasants. a pheasant should have a clear, steady fire, but not a fierce one. the pheasant, being a rather dry bird, requires to be larded, or put a piece of beef or a rump steak into the inside of it before roasting. wild ducks. in order to serve these birds in their most succulent state and finest flavor, let them hang in their feathers for a few days after being shot; then pluck, clean, and draw, and roast them in a quick oven or before a brisk fire; dredge and baste them well, and allow them twenty minutes to roast; serve them with gravy sauce and red currant jelly, or with a gravy sauce to which a chopped shallot and the juice of an orange has been added. wild fowl sauce. the following exquisite sauce is applicable to all wild fowl: take one saltspoon of salt, half to two-thirds salt spoon of cayenne, one dessert spoon lemon juice, one dessert spoon powdered sugar, two dessert spoons harvey sauce, three dessert spoons port wine, well mixed and heated; score the bird and pour the sauce over it. brown fricassee of rabbits. cut a couple of rabbits into joints, fry these in a little fresh butter till they are of a light brown color; then put them into a stewpan, with a pint of water, two tablespoonfuls of lemon juice, the same of mushroom catchup, one of worcester sauce, and a couple of burnt onions, a little cayenne and salt; stew over a slow fire till perfectly done; then take out the meat, strain the gravy, and thicken it with a little flour if necessary; make it quite hot, and pour it over the rabbits. orange pudding. beat up the yolks of eight eggs, grate the yellow rinds from two oranges, add these to a quarter of a pound of finely powdered sugar, the same weight of fresh butter, three teaspoonfuls of orange-flower water, two glasses of sherry wine, two or three stale naples biscuits or lady fingers, and a teacupful of cream. line a dish with puff paste, pour in the ingredients, and bake for half an hour in a good oven. venison pastry. a neck or breast of venison is rendered very savory by treating it as follows: take off the skin and cut the meat off the bones into pieces of about an inch square; put these, with the bones, into a stewpan, cover them with veal or mutton broth, add two thirds of a teaspoon of powdered mace, half a dozen allspice, three shallots chopped fine, a teaspoonful of salt, a saltspoon of cayenne, and a tumbler of port wine; stew over a slow fire until the meat is half done, then take it out and let the gravy remain on the fire ten or fifteen minutes longer. line a good sized dish with pastry, arrange your meat on it, pour the gravy upon it through a sieve, adding the juice of a lemon; put on the top crust, and bake for a couple of hours in a slow oven. christmas red round. rub well into a round of beef a half pound of saltpeter, finely powdered. next day mix half an ounce of cloves, half an ounce of black pepper, the same quantity of ground allspice, with half a pound of salt; wash and rub the beef in the brine for a fortnight, adding every other day a tablespoonful of salt. at the expiration of the fortnight, wipe the beef quite free from the brine, and stuff every interstice that you can find with equal portions of chopped parsley, and mixed sweet herbs in powder, seasoned with ground allspice, mace, salt, and cayenne. do not be sparing of this mixture. put the round into a deep earthen pan, fill it with strong ale, and bake it in a very slow oven for eight hours, turning it in the liquor every two hours, and adding more ale if necessary. this is an excellent preparation to assist in the "keeping of the christmas season." plum porridge for christmas festivities. make a good strong broth from four pounds of veal and an equal quantity of shin of beef. strain and skim off the fat when cold. wash and stone three pounds and a half of raisins; wash and well dry the same weight of best zante currants; take out the stones from two and a half pounds of french prunes; grate up the crumbs of two small loaves of wheat bread; squeeze the juice of eight oranges and four lemons; put these, with a teaspoonful of powdered cinnamon, a grated nutmeg, half a dozen cloves, and five pounds of sugar into your broth; stir well together, and then pour in three quarts of sherry. set the vessel containing the mixture on a slow fire. when the ingredients are soft add six bottles of hock; stir the porridge well, and as soon as it boils it is fit for use. sugared pears. half a dozen of those fine pears called the "bartlett" will make a small dish worthy the attention of any good christian who has a sweet tooth in his head. pare the fruit, cut out the cores, squeeze lemon juice over them, which will prevent their discoloration. boil them gently in enough sirup to cover them till they become tender. serve them cold, with naples biscuit round the dish. table beer. table beer of a superior quality may be brewed in the following manner, a process well worth the attention of the gentleman, the mechanic, and the farmer, whereby the beer is altogether prevented from working out of the cask, and the fermentation conducted without any apparent admission of the external air. i have made the scale for one barrel, in order to make it more generally useful to the community at large; however the same proportions will answer for a greater or less quantity, only proportioning the materials and utensils. take one peck of good malt, ground, one pound of hops, put them in twenty gallons of water, and boil them for half an hour; then run them into a hair-cloth bag or sieve, so as to keep back the hops and malt from the wort, which when cooled down to sixty-five degrees by fahrenheit's thermometer, add to it two gallons of molasses, with one pint, or a little less, of good yeast. mix these with your wort, and put the whole into a clean barrel, and fill it up with cold water to within six inches of the bung hole (this space is requisite to leave room for fermentation), bung down tight. if brewed for family use, would recommend putting in the cock at the same time, as it will prevent the necessity of disturbing the cask afterward. in one fortnight this beer may be drawn and will be found to improve to the last. mince meat. this inevitable christmas luxury is vastly improved by being mixed some days before it is required for use; this gives the various ingredients time to amalgamate and blend. peel, core, and chop fine a pound of pippin apples, wash and clean a pound of zante currants, stone one pound of bloom raisins, cut into small pieces a pound of citron, remove the skin and gristle from a pound and a half of cold roast or boiled beef, and carefully pick a pound of beef suet; chop these well together. cut into small bits three-quarters of a pound of mixed candied orange and lemon peel; mix all these ingredients well together in a large earthen pan. grate one nutmeg, half an ounce of powdered ginger, quarter of an ounce of ground cloves, quarter of an ounce of ground allspice and coriander seed mixed, and half an ounce of salt. grate the yellow rind of three lemons, and squeeze the juice over two pounds of fine sugar. put the grated yellow rind and all the other ingredients in a pan; mix well together, and over all pour one pint of brandy, one pint of sherry, and one pint of hard cider; stir well together, cover the pan closely, and when about to use the mince meat, take it from the bottom of the pan. pumpkin pie. "what moistens the lip, and what brightens the eye? what calls back the past like the rich pumpkin pie?" stew about two pounds of pumpkins, then add to it three-quarters of a pound of sugar, and the same quantity of butter, well worked together; stir these into the pumpkin and add a teaspoonful of powdered mace and grated nutmeg, and a little ground cinnamon; then add a gill of brandy, beat them well together, and stir in the yolks of eight well-beaten eggs. line the pie plates with puff paste, fill them with the pumpkin mixture, grate a little nutmeg over the top, and bake. brandy punch. take three dozen lemons, chip off the yellow rinds, taking care that none of the white underlying pith is taken, as that would make the punch bitter, whereas the yellow portion of the rinds is that in which the flavor resides and in which the cells are placed containing the essential oil. put this yellow rind into a punch bowl, add to it two pounds of lump sugar; stir the sugar and peel together with a wooden spoon or spatula for nearly half an hour, thereby extracting a greater quantity of the essential oil. now add boiling water, and stir until the sugar is completely dissolved. squeeze and strain the juice from the lemons and add it to the mixture; stir together and taste it; add more acid or more sugar, as required, and take care not to render it too watery. "rich of the fruit and plenty of sweetness," is the maxim. now measure the sherbet, and to every three quarts add a pint of cognac brandy and a pint of old jamaica rum, the spirit being well stirred as poured in. this punch may be bottled and kept in a cool cellar; it will be found to improve with age. boeuf a la mode (family style). the rump is the most applicable for this savory dish. take six or eight pounds of it, and cut it into bits of a quarter of a pound each; chop a couple of onions very fine; grate one or two carrots; put these into a large stewpan with a quarter of a pound of fresh butter, or fresh and well clarified beef drippings; while this is warming, cover the pieces of beef with flour; put them into the pan and stir them for ten minutes, adding a little more flour by slow degrees, and taking great care that the meat does not burn. pour in, a little at a time, a gallon of boiling water; then add a couple of drachms of ground allspice, one of black pepper, a couple of bay leaves, a pinch each of ground cloves and mace. let all this stew on a slow fire, and very gently, for three hours and a quarter; ascertain with a fork if the meat be tender; if so, you may serve it in a tureen or deep dish. a well-dressed salad is the proper accompaniment of boeuf à la mode. punch jelly. make a bowl of punch according to the directions for brandy punch, only a _little_ stronger. to every pint of punch add an ounce of gelatine dissolved in half a pint of water; pour this into the punch while quite hot, and then fill your moulds, taking care not to disturb it until the jelly is completely set. this preparation is a very agreeable refreshment, but should be used in moderation. the strength of the punch is so artfully concealed by its admixture with the gelatine that many persons, particularly of the softer sex, have been tempted to partake so plentifully of it as to render them somewhat unfit for waltzing or quadrilling after supper. orange salad. this somewhat inappropriately-named dish is made by removing the rind and cutting the fruit in slices crosswise and adding equal quantities of brandy and madeira, in proportion to the quantity of fruit thus dressed, strewing a liberal allowance of finely-powdered sugar over all. cranberry jelly. put two quarts of cranberries into a large earthen pipkin, and cover them with water; place them on a moderate fire, and boil them until they are reduced to a soft pulp; then strain and press them through a hair sieve into an earthen or stone ware pan, and for each pint of liquid pulp allow one pound of pulverized sugar; mix the pulp and sugar together in a bright copper basin and boil, stirring constantly for ten or fifteen minutes, or until the mixture begins to coagulate upon the spatula; then remove it from the fire and fill your moulds; let them stand in a cool place to set. when wanted for use, turn it out of the mould in the same manner as other jellies. jove's nectar. for three gallons, peel the yellow rind from one and a half dozen fresh lemons, very thin, and steep the peelings for forty-eight hours in a gallon of brandy; then add the juice of the lemons, with five quarts of water, three pounds of loaf sugar, and two nutmegs grated; stir it till the sugar is completely dissolved, then pour in three quarts of new milk, _boiling hot_, and let it stand two hours, after which run it through a jelly bag till it is fine. this is fit for immediate use, but may be kept for years in bottles, and will be improved by age. plum, or black cake. for this christmas luxury take one pound of butter and one pound of pulverized sugar; beat them together to a cream, stir in one dozen eggs beaten to a froth, beat well together, and add one pound of sifted flour; continue the beating for ten minutes, then add and stir in three pounds of stoned raisins, three pounds of zante currants, washed, cleaned, and dried, a pound and a half of citron sliced and cut into small pieces, three grated nutmegs, quarter of an ounce of powdered mace, half an ounce of powdered cinnamon, and half a teaspoonful of ground cloves; mix all well together; bake in a well-buttered pan in a slow oven for four hours and a half. black cake (parkinson's own). "if you have lips, prepare to smack them now." --_shakspeare, slightly altered._ take one and a half pounds of the best butter, and the same weight of pulverized sugar; beat them together to a cream; stir into this two dozen eggs, beaten to a froth; add one gill of old jamaica rum; then add one and a half pounds of sifted flour. stir and beat all well together, and add two pounds of finest bloom raisins, stoned; two pounds of zante currants, washed, cleaned, and dried; one pound of preserved citron, sliced thinly and cut into small pieces; one pound of preserved french cherries, in halves; one pound of green gages, and one pound of preserved apricots, stoned and cut into small pieces; half a pound of preserved orange and lemon peel, mixed, and cut into small pieces; three grated nutmegs, half an ounce of ground mace, half an ounce of powdered cinnamon, and a quarter ounce of ground cloves. mix all the ingredients well together, and bake in a well-buttered mould or pan, in a _slow oven_, for five and a half hours. this cake is vastly improved by age. those intended for the christmas festivities should be made at or about the first of october; then put the cake into a round tin box, half an inch larger in diameter than the cake; then pour over it a bottle of the best brandy mixed with half a pint of pure lemon, raspberry, strawberry, or simple sirup, and one or more bottles of champagne. now put on the lid of the box, and have it carefully soldered on, so as to make all perfectly air-tight. put it away in your store-room, and let stand till christmas, only reversing the box occasionally, in order that the liquors may permeate the cake thoroughly. this heroic treatment causes the ingredients to amalgamate, and the flavors to harmonize and blend more freely; and when, on christmas day, you bring out this hermit, after doing a three months' penance in a dark cell, it will come out rich, succulent, and unctuous; you will not only have a luxury, "fit to set before a king," or before the empress of india, but fit to crown a feast of the very gods themselves, on high olympus' top. potatoes (parkinson style). take two or three fine white potatoes, raw; peel and chop them up _very, very fine_. then chop up just as fine the breast of a good-sized boiled fowl; they should be chopped as fine as unboiled rice; mix the meat and the potatoes together, and dust a _very little_ flour over them and a pinch or two of salt. now put an ounce or so of the best butter into a frying pan, and when it is hot, put in the mixture, and stir constantly with a wooden spatula until they are fried to a nice golden color, then immediately serve on a hot plate. cold boiled ham grated fine, or boiled beef tongue chopped very fine, may be used instead of chicken, omitting the salt. a dozen or two of prime oysters, parboiled, drained, and chopped fine, mixed with the potatoes prepared as above, and fried, makes a most delicious lunch or supper dish. try any of the above styles, and say no, if you can. * * * * * the bayeux tapestry comet. professor hind, of the british nautical almanac office, recently sent an interesting letter to the london _times_ on the comet depicted in that famous piece of embroidery known as the bayeux tapestry. probably no one of the great comets recorded in history has occasioned a more profound impression upon mankind in the superstitious ages than the celebrated body which appeared in the spring of the year , and was regarded as the precursor of the invasion of england by william the norman. as pingre, the eminent cometographer, remarks, it forms the subject of an infinite number of relations in the european chronicles. the comet was first seen in china on april , . it appeared in england about easter sunday, april , and disappeared about june . professor hind finds in ancient british and chinese records abundant grounds for believing that this visitant was only an earlier appearance of halley's great comet, and he traces back the appearances of this comet at its several perihelion passages to b.c. . the last appearance of halley's comet was in , and according to pontecoulant's calculations, its next perihelion passage will take place may , . * * * * * lack of sun light. some interesting information as to the way in which the human system is affected under the peculiar conditions of work in mines has been furnished by m. fabre, from experiences connected with the coal mines of france. he finds that the deprivation of solar light causes a diminution in the pigment of the skin, and absence of sunburning, but there is no globular anæmia--that is, diminution in the number of globules in the blood. internal maladies seem to be more rare. while there is no essential anæmia in the miners, the blood globules are often found smaller and paler than in normal conditions of life, this being due to respiration of noxious gases, especially where ventilation is difficult. the men who breathe too much the gases liberated on explosion of powder or dynamite suffer more than other miners from affections of the larynx, the bronchia, and the stomach. ventilation sometimes works injury by its cooling effect. * * * * * synthetic experiments on the artificial reproduction of meteorites. by means of igneous fusion the authors have succeeded in reproducing two types of crystalline associations, which, in their mineralogical composition and the principal features of their structure, are analogous, if not identical with certain oligosideric meteorites. the only notable difference results from the habitual brecchoid state of the meteorites, which contrasts with state of quiet solidification of the artificial compounds.--_f. fouqué and michel lévy._ * * * * * a catalogue, containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . , stitched in paper, or $ . , bound in stiff covers. combined rates.--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, park row, new york, n.y. * * * * * patents. in connection with the scientific american, messrs. munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats, trade marks, their costs, and how procured, with hints for procuring advances on inventions. address munn & co., park row, new york. branch office, cor. f and th sts., washington, d.c. distributed proofreaders team [illustration] scientific american supplement no. new york, january , scientific american supplement. vol. xix, no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. metallurgy, chemistry, etc.--the elasticity of metals. the liquefaction of the elementary gases.--by jules jamin. examination of fats. notes on nitrification.--by r. warington.--paper read before the british association at montreal. ii. engineering and mechanics.--flow of water through hose pipes. iron pile planks in the construction of foundations under water.-- engravings. sound signals.--extracts from a paper by a.b. johnson.--treating of gongs, guns, rockets, bells, whistling buoys, bell buoys, locomotive whistles, trumpets, the siren, and the use of natural orifices.-- engravings. trevithick's high pressure engine at crewe.-- engravings. planetary wheel trains.--by prof. c.w. maccord.--with a page and a half of illustrations. bridge over the river indus, at attock. punjaub, northern state railway, india.--full page illustrations. the harrington rotary engine.-- figures. iii. technology.--testing car varnishes.--by d.d. robertson. aniline dyes in dress materials.--by prof. chas. o'neill. iv. decorative art.--a. chippendale sideboard.--with engraving. v. physics, magnetism, etc.--the fallacy of the present theory of sound.--abstract of a lecture by dr. h.a. mott. the fixation of magnetic phantoms.--with engraving. vi. natural history.--researches on the origin and life histories of the least and lowest living things---by rev. w.h. dallinger. vii. medicine, etc.--case of resuscitation and recovery after apparent death by hanging.--by dr. e.w. white. viii. miscellaneous.--the inventors' institute.--address of the chairman at the opening of the twenty-second session of the institute, october . the new central school at paris.-- engravings. * * * * * flow of water through hose pipes. at a recent meeting in this city of the american society of civil engineers, a paper by edmund b. weston was read, giving the description and result of experiments on the flow of water through a ½ inch hose and through nozzles of various forms and sizes; also giving the results of experiments as to the height of jets of water. the experiments were made at providence, r.i. the water was taken from a hydrant to the head of which were attached couplings holding two pressure gauges, and from the couplings the hose extended to a tank holding , gallons, so arranged as to measure accurately the time and amount of delivery of water by the hose. different lengths of hose were used. the experiments resulted in the following formula for flow from coupling: . for hose between and feet in length, and where great accuracy is required: --------------------------------------------------- / gh v = / --------------------------------------------------- / / . \ \/ - . d^{ } + ( . + ------- ) . d^{ }l. \ --- / \/ v [tex: v = \sqrt{\frac{ gh}{ - . d^ + ( . + \frac{ . }{\sqrt{v}}) . d^ l}}.] . for all lengths of hose, a reliable general formula: ---------------------------------------------- / h v = / ---------------------------------------------- \/ . - . d^{ } + . d^{ }l. [tex: v = \sqrt{\frac{h}{ . - . d^ + . d^ l}}.] g being velocity of efflux in feet per second. h, head in feet indicated by gauge. d, of coupling in inches. l, length of hose in feet from gauge. v, velocity in ½ inch hose. forty-five experiments were made on ring nozzles, resulting in the following formula: f = . v². f being loss of head in feet owing to resistance of nozzle, and v the velocity of the contracted vein in feet per second. thirty-five experiments were made with smooth nozzles, resulting in the following formula: f = . v². f being the loss of head in feet owing to resistance, and v the velocity of efflux in feet per second. experiments show that a prevailing opinion is incorrect that jets will rise higher from ring nozzles than from smooth nozzles. box's formula for height of jets of water compares very favorably with experimental results. * * * * * iron pile planks in the construction of foundations under water. the annexed engravings illustrate a method of constructing subaqueous foundations by the use of iron pile planks. these latter, by reason of their peculiar form, present a great resistance, not only to the vertical blow of the pile driver (as it is indispensable that they should), but also to horizontal pressure when excavating is being done or masonry being constructed within the space which they circumscribe. polygonal or curved perimeters may be circumscribed with equal facility by joining the piles, the sides of one serving as a guide to that of its neighbor, and special pieces being adapted to the angles. preliminary studies will give the dimensions, form, and strength of the iron to be employed. the latter, in fact, will be rolled to various thicknesses according to the application to be made of it. we may remark that the strength of the iron, aside from that which is necessary to allow the pile to withstand a blow in a vertical direction, will not have to be calculated for all entire resistance to the horizontal pressure due to a vacuum caused by the excavation, for the stiffness of the piles may be easily maintained and increased by establishing string-pieces and braces in the interior in measure as the excavation goes on. [illustration: fig. .--construction of a dock wall behind paponots iron pile planks.] the system is applicable to at least three different kinds of work: ( ) the making of excavations with a dredge and afterward concreting without pumping out the water. ( ) the removal of earth or the construction of masonry under protection from water (fig. ). ( ) the making of excavations by dredging and afterward concreting without pumping, mid then, after the beton has set, pumping out the water in order to continue the masonry in the open air. this construction of masonry in the open air has the great advantage of allowing the water to evaporate from the mortar, and consequently of causing it to dry and effect a quick and perfect cohesion of the materials employed. [illustration: fig. .--traverse section of two piles connected by mortar joints.] this system may likewise be employed with advantage for the forming of stockades in rivers, or for building sea walls. a single row of pile planks will in many cases suffice for the construction of dock walls in the river or ocean when the opposite side is to be filled in, or in any other analogous case (fig. ). the piles are driven by means of the ordinary apparatus in use. their heads are covered with a special apparatus to prevent them from being flattened out under the blows of the pile driver. they may be made in a single piece or be composed of several sections connected together with rivets. they are designed according to circumstances, to be left in the excavation in order to protect the masonry, or to be removed in their entirety or in parts, as is done with caissons. in case they are to remain wholly or in part in the excavation, they are previously galvanized or painted with an inoxidizable coating in order to protect them and increase their durability. the points of the piles, whatever be their form and arrangement, are strengthened by means of steel pieces, which assure of their penetrating hard and compact earth. [illustration: fig. .--dredging within a space circumscribed by iron pile planks.] fig. represents a dredge at work within a space entirely circumscribed by pile planks. here, after the excavation is finished, beton will be put down by means of boxes with hinged bottoms, and the water will afterward be pumped out in order to allow the masonry to be constructed in the open air. fig. shows a transverse section of two of these pile planks united by mortar joints. this system is the invention of mr. papenot.--_revue industrielle._ * * * * * an atmospheric battery. great ingenuity is being shown in the arrangement of new forms of primary batteries. the latest is that devised by m. jablochkoff, which acts by the effect of atmospheric moisture upon the metal sodium. a small rod of this metal is flattened into a plate, connected at one end to a copper wire. there is another plate of carbon, not precisely the same as that used for arc lights or ordinary batteries, but somewhat lighter in texture. this plate is perforated, and provided with small wooden pegs. the sodium plate is wrapped in silk paper, and pressed upon the carbon in such a manner that the wooden pegs penetrate the soft sodium. for greater security the whole is tied together with a few turns of fine iron wire; care being taken that the wire does not form an electric contact between the sodium and the carbon. the element is then complete, the carbon and the small copper wire being the electrodes. the sodium, on exposure to the air, becomes oxidized, forming caustic soda, which with the moisture of the air dissolves, and drains gradually away in the form of a concentrated solution; thus constantly exposing the fresh surface of the metal, which renders the reaction continuous. the price of the element is lower than would be expected at first sight from the employment of so expensive a metal. the present cost of sodium is frs. per kilogramme; but m. jablochkoff thinks that on the large scale the metal might be obtained at a very low figure. the elements are grouped in sets of ten, hung upon rods in such a manner that the solution as formed may drain off. such a battery continues in action as long as the air contains moisture; the only means of stopping it is to shut it up in an air-tight case. the electro-motive force depends on the degree of humidity in the air, and also upon the temperature. * * * * * analysis of perfumed scouring pastes.--the analysis of no. resulted in water and traces of myrbane oil, . per cent.; fatty acid, melting at ° f., . per cent.; iron peroxide, . per cent.; silicic acid, . per cent.; alumina, . per cent.; lime and magnesia, traces. the iron peroxide is partly soluble in hydrochloric acid, the alumina entirely so as silicate. the scouring paste, therefore, is composed of per cent. fatty (palm oil) acid, per cent. jeweler's rouge, per cent. pumice-stone powder. * * * * * sound signals. in appleton's "annual cyclopædia" for , mr. arnold b. johnson, chief clerk of the lighthouse board, contributes a mass of very interesting information, under the above title. his descriptions of the most approved inventions relating thereto are interesting, and we make the following extracts: the sound signals generally used to guide mariners, especially during fogs, are, with certain modifications, sirens, trumpets, steam-whistles, bell-boats, bell-buoys, whistling buoys, bells struck by machinery, cannons fired by powder or gun cotton, rockets, and gongs. _gongs._--gongs are somewhat used on lightships, especially in british waters. they are intended for use at close quarters. leonce reynaud, of the french lighthouse service, has given their mean effective range as barely yards. they are of most use in harbors, short channels, and like places, where a long range would be unnecessary. they have been used but little in united states waters. the term "effective range" is used here to signify the actual distance at which, under the most unfavorable circumstances, a signal can generally be heard on board of a paddle-wheel steamer in a heavy sea-way. _guns._--the use of guns is not so great as it once was. instances are on record in which they were quite serviceable. admiral sir a. milne said he had often gone into halifax harbor, in a dense fog like a wall, by the sound of the sambro fog gun. but in the experiments made by the trinity house off dungeness in january, , in calm weather, the report of an eighteen-pounder, with three pounds of powder, was faint at four miles. still, in the trinity house experiments of , made in light weather with a light gun, the report was clearly heard seven miles away. dr. gladstone records great variability in the range of gun-sound in the holyhead experiments. prof. henry says that a twenty-four-pounder was used at point boneta, san francisco bay, cal., in - , and that, by the help of it alone, vessels came into the harbor during the fog at night as well as in the day, which otherwise could not have entered. the gun was fired every half hour, night and day, during foggy and thick weather in the first year, except for a time when powder was lacking. during the second year there were , discharges. it was finally superseded by a bell-boat, which in its turn was after a time replaced by a siren. a gun was also used at west quoddy head, maine. it was a carronade, five feet long, with a bore of five and one-quarter inches, charged with four pounds of powder. the gun was fired on foggy days when the boston steamer was approaching the lighthouse from st. johns, and the firing was begun when the steamer's whistle was heard, often when she was six miles away, and was kept up as fast as the gun could be loaded, until the steamer answered with its whistle. the report of the gun was heard from two to six miles. "this signal was abandoned," prof. henry says, "because of the danger attending its use, the length of intervals between successive explosions, and the brief duration of the sound, which renders it difficult to determine its direction with accuracy." in there were three fog guns on the english coast, iron eighteen-pounders, carrying a three pound charge of powder, which were fired at intervals of fifteen minutes in two places, and of twenty minutes in the other. the average duration of fog at these stations was said to be about six hours, and as it not unfrequently lasted twenty hours, each gun required two gunners, who had to undergo severe labor, and the risk of remissness and irregularity was considerable. in the interval between charges was reduced to ten minutes. the trinity house, in its experiments at south foreland, found that the short twenty-four pound howitzer gave a better sound than the long eighteen-pounder. tyndall, who had charge of the experiments, sums up as to the use of the guns as fog-signals by saying: "the duration of the sound is so short that, unless the observer is prepared beforehand, the sound, through lack of attention rather than through its own powerlessness, is liable to be unheard. its liability to be quenched by local sound is so great that it is sometimes obliterated by a puff of wind taking possession of the ears at the time of its arrival. its liability to be quenched by an opposing wind, so as to be practically useless at a very short distance to windward, is very remarkable.... still, notwithstanding these drawbacks, i think the gun is entitled to rank as a first-class signal." the minute gun at sea is known the world over as a signal of distress. the english lightships fire guns to attract the attention of the lifeboat crew when shipwrecks take place in sight of the ships, but out of sight of the boats; and guns are used as signals of approaching floods at freshet times in various countries. _rockets._--as a signal in rock lighthouses, where it would be impossible to mount large pieces of apparatus, the use of a gun-cotton rocket has been suggested by sir richard collinson, deputy-master of the trinity house. a charge of gun-cotton is inclosed in the head of a rocket, which is projected to the height of perhaps , feet, when the cotton is exploded, and the sound shed in all directions. comparative experiments with the howitzer and rocket showed that the howitzer was beaten by a rocket containing twelve ounces, eight ounces, and even four ounces of gun-cotton. large charges do not show themselves so superior to small charges as might be expected. some of the rockets were heard at a distance of twenty-five miles. tyndall proposes to call it the collinson rocket, and suggests that it might be used in lighthouses and lightships as a signal by naval vessels. _bells._--bells are in use at every united states lightstation, and at many they are run by machinery actuated by clock-work, made by mr. stevens, of boston, who, at the suggestion of the lighthouse board, has introduced an escapement arrangement moved by a small weight, while a larger weight operates the machinery which strikes the bell. these bells weigh from to , pounds. there are about in use on the coasts of the united states. experiments made by the engineers of the french lighthouse establishment, in - , showed that the range of bell-sounds can be increased with the rapidity of the bell-strokes, and that the relative distances for , , and bell-strokes a minute were in the ratio of , - / , and - / . the french also, with a hemispherical iron reflector backed with portland cement, increased the bell range in the ratio of to over a horizontal arc of °, beyond which its effect gradually diminished. the actual effective range of the bell sound, whatever the bell size, is comparatively short, and, like the gong, it is used only where it needs to be heard for short distances. mr. cunningham, secretary of the scottish lighthouse establishment, in a paper on fog signals, read in february, , says the bell at howth, weighing ¼ tons, struck four times a minute by a pound hammer falling ten inches, has been heard only one mile to windward against a light breeze during fog; and that a similar bell at kingston, struck eight times a minute, had been so heard three miles away as to enable the steamer to make her harbor from that distance. mr. beaseley, c.e., in a lecture on coast-fog signals, may , , speaks of these bells as unusually large, saying that they and the one at ballycottin are the largest on their coasts, the only others which compare with them being those at stark point and south stack, which weigh ¾ cwt. and ½ cwt. respectively. cunningham, speaking of the fog-bells at bell rock and skerryvore lighthouses, says he doubts if either bell has been the means of saving a single vessel from wreck during fog, and he does not recall an instance of a vessel reporting that she was warned to put about in the fog, or that she ascertained her position in any respect by hearing the sound of the bell in either place. gen. duane, u.s.a., says a bell, whether operated by hand or machinery, cannot be considered an efficient fog signal on the sea-coast. in calm weather it cannot be heard half the time at a greater distance than one mile, while in rough weather the noise of the surf will drown its sound to seaward altogether. the use of bells is required, by the international code, on ships of all nations, at regular intervals during fog. but turkish ships are allowed to substitute the gong or gun, as the use of bells is forbidden to the followers of mohammed. [illustration: fig. .--courtenay's whistling buoy.] _whistling buoys._--the whistling buoy now in use was patented by mr. j.m. courtenay, of new york. it consists of an iron pear-shaped bulb, feet across at its widest part, and floating feet out of water. inside the bulb is a tube inches across, extending from the top through the bottom to a depth of feet, into water free from wave motion. the tube is open at its lower end, but projects, air-tight, through the top of the bulb, and is closed with a plate having in it three holes, two for letting the air into the tube, and one between the others for letting the air out to work the -inch locomotive whistle with which it is surmounted. these holes are connected with three pipes which lead down to near the water level, where they pass through a diaphragm which divides the outer cylinder into two parts. the great bulb which buoys up the whole mass rises and falls with the motion of the waves, carrying the tube up and down with it, thus establishing a piston-and-cylinder movement, the water in the tube acting as an immovable piston, while the tube itself acts as a moving cylinder. thus the air admitted through valves, as the buoy rises on the wave, into that part of the bulb which is above water, is compressed, and as the buoy falls with the wave, it is further compressed and forced through a ½ inch pipe which at its apex connects with the whistle. the dimensions of the whistling buoy have recently been much diminished without detracting materially from the volume of sound it produces. it is now made of four sizes. the smallest in our waters has a bulb feet in diameter and a tube feet in length, and weighs but , pounds. the largest and oldest whistling buoy has a -foot bulb, a tube feet long, and weighs , pounds. there are now of these whistling buoys on the coast of the united states, which have cost, with their appurtenances, about $ , each. it is a curious fact that, in proportion as they are useful to the mariner, they are obnoxious to the house dweller within earshot of them, and that the lighthouse board has to weigh the petitions and remonstrances before setting these buoys off inhabited coasts. they can at times be heard miles, and emit an inexpressibly mournful and saddening sound. the inspector of the first lighthouse district, commander picking, established a series of observations at all the light stations in the neighborhood of the buoys, giving the time of hearing it, the direction of the wind, and the state of the sea, from which it appears that in january, , one of these buoys was heard every day at a station - / miles distant, every day but two at one ¼ miles distant, times at one ½ miles distant, and times at one ½ miles distant. it is heard by the pilots of the new york and boston steamers at a distance of one-fifth of a mile to miles, and has been frequently heard at a distance of miles, and even, under specially favorable circumstances, miles. the whistling buoy is also used to some extent in british, french, and german waters, with good results. the latest use to which it has been put in this country has been to place it off the shoals of cape hatteras, where a light ship was wanted but could not live, and where it does almost as well as a light ship would have done. it is well suited for such broken and turbulent waters, as the rougher the sea the louder its sound. [illustration: fig. .--brown's bell buoy.] _bell-buoys._--the bell-boat, which is at most a clumsy contrivance, liable to be upset in heavy weather, costly to build, hard to handle, and difficult to keep in repair, has been superseded by the brown bell-buoy, which was invented by the officer of the lighthouse establishment whose name it bears. the bell is mounted on the bottom section of an iron buoy feet inches across, which is decked over and fitted with a framework of -inch angle-iron feet high, to which a -pound bell is rigidly attached. a radial grooved iron plate is made fast to the frame under the bell and close to it, on which is laid a free cannon-ball. as the buoy rolls on the sea, this ball rolls on the plate, striking some side of the bell at each motion with such force as to cause it to toll. like the whistling-buoy, the bell-buoy sounds the loudest when the sea is the roughest, but the bell-buoy is adapted to shoal water, where the whistling-buoy could not ride; and, if there is any motion to the sea, the bell-buoy will make some sound. hence the whistling-buoy is used in roadsteads and the open sea, while the bell-buoy is preferred in harbors, rivers, and the like, where the sound-range needed is shorter, and smoother water usually obtains. in july, , there were of these bell-buoys in united states waters. they cost, with their fitments and moorings, about $ , each. _locomotive-whistles._--it appears from the evidence given in , before the select committee raised by the english house of commons, that the use of the locomotive-whistle as a fog-signal was first suggested by mr. a. gordon, c.e., who proposed to use air or steam for sounding it, and to place it in the focus of a reflector, or a group of reflectors, to concentrate its sounds into a powerful phonic beam. it was his idea that the sharpness or shrillness of the whistle constituted its chief value. and it is conceded that mr. c.l. daboll, under the direction of prof. henry, and at the instance of the united states lighthouse board, first practically used it as a fog-signal by erecting one for use at beaver tail point, in narragansett bay. the sounding of the whistle is well described by price-edwards, a noted english lighthouse engineer, "as caused by the vibration of the column of air contained within the bell or dome, the vibration being set up by the impact of a current of steam or air at a high pressure." it is probable that the metal of the bell is likewise set in vibration, and gives to the sound its timbre or quality. it is noted that the energy so excited expends its chief force in the immediate vicinity of its source, and may be regarded, therefore, as to some extent wasted. the sound of the whistle, moreover, is diffused equally on all sides. these characteristics to some extent explain the impotency of the sound to penetrate to great distances. difference in pitch is obtained by altering the distance between the steam orifice and the rim of the drum. when brought close to each other, say within half an inch, the sound produced is very shrill, but it becomes deeper as the space between the rim and the steam or air orifice is increased. prof. henry says the sound of the whistle is distributed horizontally. it is, however, much stronger in the plane containing the lower edge of the bell than on either side of this plane. thus, if the whistle is standing upright in the ordinary position, its sound is more distinct in a horizontal plane passing through the whistle than above it or below it. the steam fog-whistle is the same instrument ordinarily used on steamboats and locomotives. it is from to inches in diameter, and is operated by steam under a pressure of from to pounds. an engine takes its steam from the same boiler, and by an automatic arrangement shuts off and turns on the steam by opening and closing its valves at determined times. the machinery is simple, the piston-pressure is light, and the engine requires no more skilled attention than does an ordinary station-engine. "the experiments made by the trinity house in - seem to show," price-edwards says, "that the sound of the most powerful whistle, whether blown by steam or hot air, was generally inferior to the sound yielded by other instruments," and consequently no steps were taken to extend their use in great britain, where several were then in operation. in canadian waters, however, a better result seems to have been obtained, as the deputy minister of marine and fisheries, in his annual report for , summarizes the action of the whistles in use there, from which it appears that they have been heard at distances varying with their diameter from to miles. the result of the experiments made by prof. henry and gen. duane for the united states lighthouse board, reported in , goes to show that the steam-whistle could be heard far enough for practical uses in many positions. prof. henry found that he could hear a -inch whistle ¼ miles with a feeble opposing wind. gen. duane heard the -inch whistle at cape elizabeth at his house in portland, maine, nine miles distant, whenever it was in operation. he heard it best during a heavy northeast snow storm, the wind blowing then directly from him, and toward the source of the sound. gen. duane also reported that "there are six fog-signals on the coast of maine; these have frequently been heard at the distance of twenty miles," ... which distance he gives as the extreme limit of the twelve-inch steam-whistle. _trumpets._--the daboll trumpet was invented by mr. c.l. daboll, of connecticut, who was experimenting to meet the announced wants of the united states lighthouse board. the largest consists of a huge trumpet seventeen feet long, with a throat three and one-half inches in diameter, and a flaring mouth thirty-eight inches across. in the trumpet is a resounding cavity, and a tongue-like steel reed ten inches long, two and three-quarter inches wide, one inch thick at its fixed end, and half that at its free end. air is condensed in a reservoir and driven through the trumpet by hot air or steam machinery at a pressure of from fifteen to twenty pounds, and is capable of making a shriek which can be heard at a great distance for a certain number of seconds each minute, by about one-quarter of the power expended in the case of the whistle. in all his experiments against and at right angles and at other angles to the wind, the trumpet stood first and the whistle came next in power. in the trial of the relative power of various instruments made by gen. duane in , the twelve-inch whistle was reported as exceeding the first-class daboll trumpet. beaseley reports that the trumpet has done good work at various british stations, making itself heard from five to ten miles. the engineer in charge of the lighthouses of canada says: "the expense for repairs, and the frequent stoppages to make these repairs during the four years they continued in use, made them [the trumpets] expensive and unreliable. the frequent stoppages during foggy weather made them sources of danger instead of aids to navigation. the sound of these trumpets has deteriorated during the last year or so." gen. duane, reporting as to his experiments in , says: "the daboll trumpet, operated by a caloric engine, should only be employed in exceptional cases, such as at stations where no water can be procured, and where from the proximity of other signals it may be necessary to vary the nature of the sound." thus it would seem that the daboll trumpet is an exceptionally fine instrument, producing a sound of great penetration and of sufficient power for ordinary practical use, but that to be kept going it requires skillful management and constant care. _the siren._--the siren was adapted from the instrument invented by cagniard de la tour, by a. and f. brown, of the new york city progress works, under the guidance of prof. henry, at the instance and for the use of the united states lighthouse establishment, which also adopted it for use as a fog-signal. the siren of the first class consists of a huge trumpet, somewhat of the size and shape used by daboll, with a wide mouth and a narrow throat, and is sounded by driving compressed air or steam through a disk placed in its throat. in this disk are twelve radial slits; back of the fixed disk is a revolving plate, containing as many similar openings. the plate is rotated , times each minute, and each revolution causes the escape and interruption of twelve jets of air or steam through the openings in the disk and rotating plate. in this way , vibrations are given during each minute that the machine is operated; and, as the vibrations are taken up by the trumpet, an intense beam of sound is projected from it. the siren is operated under a pressure of seventy-two pounds of steam, and can be heard, under favorable circumstances, from twenty to thirty miles. "its density, quality, pitch, and penetration render it dominant over such other noises after all other signal-sounds have succumbed." it is made of various sizes or classes, the number of slits in its throat-disk diminishing with its size. the dimensions given above are those of the largest. [see engraving on page , "annual cyclopædia" for .] the experiments made by gen. duane with these three machines show that the siren can be, all other things being equal, heard the farthest, the steam-whistle stands next to the siren, and the trumpet comes next to the whistle. the machine which makes the most noise consumes the most fuel. from the average of the tests it appears that the power of the first-class siren, the twelve-inch whistle, and first-class daboll trumpet are thus expressed: siren nine, whistle seven, trumpet four; and their relative expenditure of fuel thus: siren nine, whistle three, trumpet one. sound-signals constitute so large a factor in the safety of the navigator, that the scientists attached to the lighthouse establishments of the various countries have given much attention to their production and perfection, notably tyndall in england and henry in this country. the success of the united states has been such that other countries have sent commissions here to study our system. that sent by england in , of which sir frederick arrow was chairman, and captain webb, r.n., recorder, reported so favorably on it that since then "twenty-two sirens have been placed at the most salient lighthouses on the british coasts, and sixteen on lightships moored in position where a guiding signal is of the greatest service to passing navigation." the trumpet, siren, and whistle are capable of such arrangement that the length of blast and interval, and the succession of alternation, are such as to identify the location of each, so that the mariner can determine his position by the sounds. in this country there were in operation in july, , sixty-six fog-signals operated by steam or hot air, and the number is to be increased in answer to the urgent demands of commerce. _use of natural orifices._--there are, in various parts of the world, several sound-signals made by utilizing natural orifices in cliffs through which the waves drive the air with such force and velocity as to produce the sound required. one of the most noted is that on one of the farallon islands, forty miles off the harbor of san francisco, which was constructed by gen. hartmann bache, of the united states engineers, in - , and of which the following is his own description: "advantage was taken of the presence of the working party on the island to make the experiment, long since contemplated, of attaching a whistle as a fog-signal to the orifice of a subterranean passage opening out upon the ocean, through which the air is violently driven by the beating of the waves. the first attempt failed, the masonry raised upon the rock to which it was attached being blown up by the great violence of the wind-current. a modified plan with a safety-valve attached was then adopted, which it is hoped will prove permanent. ... the nature of this work called for , bricks and four barrels of cement." prof. henry says of this: "on the apex of this hole he erected a chimney which terminated in a tube surmounted by a locomotive-whistle. by this arrangement a loud sound was produced as often as the wave entered the mouth of the indentation. the penetrating power of the sound from this arrangement would not be great if it depended merely on the hydrostatic pressure of the waves, since this under favorable circumstances would not be more than that of a column of water twenty feet high, giving a pressure of about ten pounds to the square inch. the effect, however, of the percussion might add considerably to this, though the latter would be confined in effect to a single instance. in regard to the practical result from this arrangement, which was continued in operation for several years, it was found not to obviate the necessity of producing sounds of greater power. it is, however, founded on an ingenious idea, and may be susceptible of application in other cases." there is now a first-class siren in duplicate at this place. the sixty-six steam fog-signals in the waters of the united states have been established at a cost of more than $ , , and are maintained at a yearly expense of about $ , . the erection of each of these signals was authorized by congress in an act making special appropriations for its establishment, and congress was in each instance moved thereto by the pressure of public opinion, applied usually through the member of congress representing the particular district in which the signal was to be located. and this pressure was occasioned by the fact that mariners have come to believe that they could be guided by sound as certainly as by sight. the custom of the mariner in coming to this coast from beyond the seas is to run his ship so that on arrival, if after dark, he shall see the proper coast-light in fair weather, and, if in thick weather, that he shall hear fog-signal, and, taking that as a point of departure, to feel his way from the coast-light to the harbor-light, or from the fog-signal on the coast to the fog-signal in the harbor, and thence to his anchorage or his wharf. and the custom of the coaster or the sound-steamer is somewhat similar. * * * * * trevithick's engine at crewe. the old high-pressure engine of richard trevithick, which, thanks to mr. webb, has been rescued from a scrap heap in south wales, and re-erected at the crewe works. we give engravings of this engine, which have been prepared from photographs kindly furnished to us by mr. webb, and which will clearly show its design. [illustration: trevithick's high pressure engine at crewe.] the boiler bears a name-plate with the words "no. , hazeldine and co., bridgnorth," and it is evidently one of the patterns which trevithick was having made by hazeldine and co., about the year . the shell of the boiler is of cast iron, and the cylinder, which is vertical, is cast in one with it, the back end of the boiler and the barrel being in one piece as shown. at the front end the barrel has a flange by means of which it is bolted to the front plate, the plate having attached to it the furnace and return flue, which are of wrought iron. the front plate has also cast on it a manhole mouthpiece to which the manhole cover is bolted. in the case of the engine at crewe, the chimney, firehole door, and front of flue had to be renewed by mr. webb, these parts having been broken up before the engine came into his possession. the piston rod is attached to a long cast-iron crosshead, from which two bent connecting rods extend downward, the one to a crank, and the other to a crank-pin inserted in the flywheel. the connecting-rods now on this engine were supplied by mr. webb, the original ones--which they have been made to resemble as closely as possible--having been broken up. in the crewe engine as it now exists it is not quite clear how the power was taken off from the crankshaft, but from the particulars of similar engines recorded in the "life of richard trevithick," it appears that a small spur pinion was in some cases fixed on the crankshaft, and in others a spurwheel, with a crank-pin inserted in it, took the place of the crank at the end of the shaft opposite to that carrying the flywheel. in the crewe engine the flywheel, it will be noticed, is provided with a balanceweight. the admission of the steam to and its release from the cylinder is effected by a four-way cock provided with a lever, which is actuated by a tappet rod attached to the crosshead, as seen on the back view of the engine. to the crosshead is also coupled a lever having its fulcrum on a bracket attached to the boiler; this lever serving to work the feed pump. unfortunately the original pump of the crewe engine was smashed, but mr. webb has fitted one up to show the arrangement. a notable feature in the engine is that it is provided with a feed heater through which the water is forced by the pump on its way to the boiler. the heater consists of a cast-iron pipe through which passes the exhaust pipe leading from the cylinder to the chimney, the water circulating through the annular space between the two pipes. altogether the trevithick engine at crewe is a relic of the very highest interest, and it is most fortunate that it has come into mr. webb's hands and has thus been rescued from destruction. no one, bearing in mind the date at which it was built, can examine this engine without having an increased respect for the talents of richard trevithick, a man to whom we owe so much and whose labors have as yet met with such scant recognition.--_engineering._ * * * * * [continued from scientific american supplement, no. , page .] planetary wheel trains. by prof. c.w. maccord, sc. d. iv. the arrangement of planetary wheels which has been applied in practice to the greatest extent and to the most purposes, is probably that in which the axial motions of the train are derived from a fixed sun wheel. numerous examples of such trains are met with in the differential gearing of hoisting machines, in portable horse-powers, etc. the action of these mechanisms has already been fully discussed; it may be remarked in addition that unless the speed be very moderate, it is found advantageous to balance the weights and divide the pressures by extending the train arm and placing the planet-wheels in equal pairs diametrically opposite each other, as, for instance, in bogardus' horse power, fig. . [illustration: planetary wheel trains.] in trains of this description, the velocity ratio is invariable; which for the above-mentioned objects it should be. but the use of a planetary combination enables us to cause the motions of two independent trains to converge, and unite in producing a single resultant rotation. this may be done in two ways; each of the two independent trains may drive one sun-wheel, thus determining the motion of the train-arm; or, the train-arm may be driven by one of them, and the first sun-wheel by the other; then the motion of the second sun-wheel is the resultant. under these circumstances the ratio of the resultant velocity to that of either independent train is not invariable, since it may be affected by a change in the velocity of the other one. to illustrate our meaning, we give two examples of arrangements of this nature. the first is robinson's rope-making machine, fig. . the bobbins upon which the strands composing the rope are wound turn freely in bearings in the frames, g, g, and these frames turn in bearings in the disk, h, and the three-armed frame or spider, k, both of which are secured to the central shaft, s. each bobbin-frame is provided with a pinion, _a_, and these three pinions engage with the annular wheel, a. this wheel has no shaft, but is carried and kept in position by three pairs of rollers, as shown, so that its axis of rotation is the same as that of the shaft, s; and it is toothed externally as well as internally. the strands pass through the hollow axes of the pinions, and thence each to its own opening through the laying-top, t, fixed upon s, which completes the operation of twisting them into a rope. the annular wheel, a, it will be perceived, may be driven by a pinion, e, engaging with its external teeth, at a rate of speed different from that of the central shaft; and by varying the speed of that pinion, the velocity of the wheel, a, may be changed without affecting the velocity of s. it is true that in making a certain kind of rope, the velocity ratio of a and s must remain constant, in order that the strands may be equally twisted throughout; but if for another kind of rope a different degree of twist is wanted, the velocity of the pinion, e, may be altered by means of change-wheels, and thus the same machine may be used for manufacturing many different sorts. the second combination of this kind was devised by the writer as a "tell-tale" for showing whether the engines driving a pair of twin screw-propellers were going at the same rate. in fig. , an index, p, is carried by the wheel, f: the wheel, a, is loose upon the shaft of the train-arm, which latter is driven by the wheel, e. the wheels, f and _f_, are of the same size, but _a_ is twice as large as a; if then a be driven by one engine, and e by the other, at the same rate but in the opposite direction, the index will remain stationary, whatever the absolute velocities. but if either engine go faster than the other, the index will turn to the right or the left accordingly. the same object may also be accomplished as shown in fig. , the index being carried by the train-arm. it makes no difference what the actual value of the ratio a/_a_ may be, but it must be equal to f/_f_: under which condition it is evident that if a and f be driven contrary ways at equal speeds, small or great, the train-arm will remain at rest; but any inequality will cause the index to turn. in some cases, particularly when annular wheels are used, the train-arm may become very short, so that it may be impossible to mount the planet-wheel in the manner thus far represented, upon a pin carried by a crank. this difficulty may be surmounted as shown in fig. , which illustrates an arrangement originally forming a part of nelson's steam steering gear. the internal pinions, _a_, _f_, are but little smaller than the annular wheels, a, f, and are hung upon an eccentric e formed in one solid piece with the driving shaft, d. the action of a complete epicyclic train involves virtually and always the action of two suns and two planets; but it has already been shown that the two planets may merge into one piece, as in fig. , where the planet-wheel gears externally with one sun-wheel, and internally with the other. but the train may be reduced still further, and yet retain the essential character of completeness in the same sense, though composed actually of but two toothed wheels. an instance of this is shown in fig. , the annular planet being hung upon and carried by the pins of three cranks, _c_, _c_, _c_, which are all equal and parallel to the virtual train-arm, t. these cranks turning about fixed axes, communicate to _f_ a motion of circular translation, which is the resultant of a revolution, _v'_, about the axis of f in one direction, and a rotation, _v_, at the same rate in the opposite direction about its own axis, as has been already explained. the cranks then supply the place of a fixed sun-wheel and a planet of equal size, with an intermediate idler for reversing the, direction of the rotation of the planet; and the velocity of f is v'= v'( - f/f). a modification of this train better suited for practical use is shown in fig. , in which the sun-wheel, instead of the planet, is annular, and the latter is carried by the two eccentrics, e, e, whose throw is equal to the difference between the diameters of the two pitch circles; these eccentrics must, of course, be driven in the same direction and at equal speeds, like the cranks in fig. . [illustration: planetary wheel trains.] a curious arrangement of pin-gearing is shown in fig. : in this case the diameter of the pinion is half that of the annular wheel, and the latter being the driver, the elementary hypocycloidal faces of its teeth are diameters of its pitch circle; the derived working tooth-outlines for pins of sensible diameter are parallels to these diameters, of which fact advantage is taken to make the pins turn in blocks which slide in straight slots as shown. the formula is the same as that for fig. , viz.: v' = v'( - f/f), which, since f = f, reduces to v' = -v'. of the same general nature is the combination known as the "epicycloidal multiplying gear" of elihu galloway, represented in fig. . upon examination it will be seen, although we are not aware that attention has previously been called to the fact, that this differs from the ordinary forms of "pin gearing" only in this particular, viz., that the elementary tooth of the driver consists of a complete branch, instead of a comparatively small part of the hypocycloid traced by rolling the smaller pitch-circle within the larger. it is self-evident that the hypocycloid must return into itself at the point of beginning, without crossing: each branch, then, must subtend an aliquot part of the circumference, and can be traced also by another and a smaller describing circle, whose diameter therefore must be an aliquot part of the diameter of the outer pitch-circle; and since this last must be equal to the sum of the diameters of the two describing circles, it follows that the radii of the pitch circles must be to each other in the ratio of two successive integers; and this is also the ratio of the number of pins to that of the epicycloidal branches. thus in fig. , the diameters of the two pitch circles are to each other as to ; the hypocycloid has branches, and pins are used. these pins must in practice have a sensible diameter, and in order to reduce the friction this diameter is made large, and the pins themselves are in the form of rollers. the original hypocycloid is shown in dotted line, the working curve being at a constant normal distance from it equal to the radius of the roller; this forms a sort of frame or yoke, which is hung upon cranks as in figs. and . the expression for the velocity ratio is the same as in the preceding case: v¹ = v'( - f/f); which in fig. gives v¹ = v'( - / )= -¼v': the planet wheel, or epicycloidal yoke, then, has the higher speed, so that if it be desired to "gear up," and drive the propeller faster than the engine goes (and this, we believe, was the purpose of the inventor), the pin-wheel must be made the driver; which is the reverse of advantageous in respect to the relative amounts of approaching and receding action. in figs. and are given the skeletons of galloway's device for ratios of : and : respectively, the former having four branches and three pins, the latter three branches and two pins. following the analogy, it would seem that the next step should be to employ two branches with only one pin; but the rectilinear hypocycloid of fig. is a complete diameter, and the second branch is identical with the first; the straight tooth, then, could theoretically drive the pin half way round, but upon its reaching the center of the outer wheel, the driving action would cease: this renders it necessary to employ two pins and two slots, but it is not essential that the latter should be perpendicular to each other. in these last arrangements, the forms of the parts are so different from those of ordinary wheels, that the true nature of the combinations is at least partially disguised. but it may be still more completely hidden, as for instance in the common elliptic trammel, fig. . the slotted cross is here fixed, and the pins, r and p, sliding respectively in the vertical and horizontal lines, control the motion of the bar which carries the pencil, s. at first glance there would seem to be nothing here resembling wheel works. but if we describe a circle upon r p as a diameter, its circumference will always pass through c, because r c p is a right angle, and the instantaneous axis of the bar being at the intersection o of a vertical line through p, with a horizontal line through r, will also lie upon this circumference. again, since o is diametrically opposite to c, we have c o = r p, whence a circle about center c with radius r p will also pass through o, which therefore is the point of contact of these two circles. it will now be seen that the motion of the bar is the same as though carried by the inner circle while rolling within the outer one, the latter being fixed; the points p and r describing the diameters l m and k n, the point d a circle, and s an ellipse; c d being the train-arm. the distance r p being always the diameter of one circle and the radius of the other, the sizes of the wheels can be in effect varied by altering that distance. thus we see that this combination is virtually the same in its action as the one shown in fig. , known as suardi's geometrical pen. in this particular case the diameter of _a_ is half of that of a; these wheels are connected by the idler, e, which merely reverses the direction without affecting the velocity of _a's_ rotation. the working train arm is jointed so as to pivot about the axis of e, and may be clamped at any angle within its range, thus changing the length of the virtual train arm, c d. the bar being fixed to _a_, then, moves as though carried by the wheel, _a¹_, rolling within a¹; the radius of _a¹_ being c d, and that of a¹ twice as great. in either instrument, the semi-major axis c x is equal to s r, and the semi-minor axis to s p. the _ellipse_, then, is described by these arrangements because it is a special form of the epitrochoid; and various other epitrochoids may be traced with suardi's pen by substituting other wheels, with different numbers of teeth, for a in fig. . another disguised planetary arrangement is found in oldham's coupling, fig. . the two sections of shafting, a and b, have each a flange or collar forged or keyed upon them; and in each flange is planed a transverse groove. a third piece, c, equal in diameter to the flanges, is provided on each side with a tongue, fitted to slide in one of the grooves, and these tongues are at right angles to each other. the axes of a and b must be parallel, but need not coincide; and the result of this connection is that the two shafts will turn in the same direction at the same rate. the fact that c in this arrangement is in reality a planetary wheel, will be perceived by the aid of the diagram, fig. . let c d be two pieces rotating about fixed parallel axes, each having a groove in which slides freely one of the arms, a c, a d, which are rigidly secured to each other at right angles. the point c of the upper arm can at the instant move only in the direction c a; and the point d of the lower arm only in the direction a d, at the same instant; the instantaneous axis is therefore at the intersection, k, of perpendiculars to a c and a d, at the points c and d. c a d k being then a rectangle, a k and c d will be two diameters of a circle whose center, o, bisects c d; and k will also be the point of contact between this circle and another whose center is a, and radius a k = c d. if then we extend the arms so as to form the cross, p k, m n, and suppose this to be carried by the outer circle, _f_, rolling upon the inner one, f, its motion will be the same as that determined by the pieces, c d; and such a cross is identical with that formed by the tongues on the coupling-piece, c, of fig. . a o is the virtual train-arm; let the center, a, of the cross move to the position b, then since the angles a o b at the center, and a c b in the circumference, stand on the same arc, a b, the former is double the latter, showing that the cross revolves twice round the center o during each rotation of c; and since a c b = a d b, c and d rotate with equal velocities, and these rotations and the revolution about o have the same direction. while revolving, the cross rotates about its traveling center, a, in the opposite direction, the contact between the two circles being internal, and at a rate equal to that of the rotations of c and d, because the velocities of the axial and the orbital motion are to each other as _f_ is to f, that is to say, as is to . since in the course of the revolution the points p and k must each coincide with c, and the points m and n with d, it follows that each tongue in fig. must slide in its groove a distance equal to twice that between the axes of the shafts. another example of a disguised planetary train is shown in fig. . let c be the center about which the train arm, t, revolves, and suppose it required that the distant shaft, b, carried by t, shall turn once backward for each forward revolution of the arm. e is a fixed eccentric of any convenient diameter, in the upper side of which is a pin, d. on the shaft, b, is keyed a crank, b g, equal in length to c d; and at any convenient point, h, on b c, or its prolongation, another crank, h f, equal also to c d, is provided with a bearing in the train-arm. the three crank pins, f, d, g, are connected by a rod, like the parallel rod of a locomotive; f d, d g, being respectively equal to h c, c b. then, as the train-arm revolves, the three cranks must remain parallel to each other; but c d being fixed, the cranks, h f and b g, will remain always parallel to their original positions, thus receiving the required motion of circular translation. the result then is the same as though the periphery of e were formed into a fixed spurwheel, a, and another, _a_, of the same size, secured on a shaft, b, the two being connected by the three equal wheels, l, m, n. it need hardly be stated that instead of the eccentric, e, a stationary crank similar and equal to b g may be used, should it be found better suited to the circumstances of the case. it is possible also to apply the planetary principle to mechanism composed partially of racks; in fact, a rack is merely a wheel of prodigious size--the limiting case, just as a right line is a circle of infinite radius. a very neat application of this principle is found in villa's pantograph, of which a full description and illustration was given in scientific american supplement, no. ; the racks, moving side by side, are the sun-wheels, and the planet-wheels are the pinions, carried by the traveling socket, by which the motion of one rack is transmitted to the other. thus far attention has been called only to combinations of circular wheels. in these the velocity ratios are constant, if we except the cases in which two independent trains converge, the two sun-wheels, or one of them and the train-arm, being driven separately--and even in those, a variable motion of the ultimate follower is obtained only by varying the speed of one or both drivers. it is not, however, necessary to employ circular wheels exclusively or even at all; wheels of other forms are capable of acting together in the relation of sun and planet, and in this way a varying velocity ratio may be produced even with a fixed sun-wheel and a single driver. we have not found, in the works of any previous writer, any intimation that noncircular wheels have ever been thus combined; and we propose in the following article to illustrate some curious results which may be thus obtained. * * * * * the fallacy of the present theory of sound. dr. h.a. mott recently delivered a lecture before the new york academy of sciences, in columbia college, on the fallacy of the present theory of sound. he commenced his lecture by stating that "the object of science was not to find out what we like or what we dislike; the object of science was truth." he then said that, as galileo stated a hypothesis should be judged by the weight of facts and the force of mathematical deductions, he claimed the theory of sound should be so examined, and not allowed to exist as a true theory simply because it is sustained by a long line of scientific names; as too many theories had been overthrown to warrant the acceptance of any one authority unless they had been thoroughly tested. dr. mott stated that dr. wilford hall was the first to attack the theory of sound and show its fallaciousness, and that many other scientists besides himself had agreed with dr. hall in his arguments and had advanced additional arguments and experiments to establish this fact. dr. mott first gave a very elaborate and still at the same time condensed statement of the current theory of sound as propounded by such men as helmholtz, tyndall, lord rayleigh, mayer, rood, sir wm. thomson, and others, and closed this section of the paper with the remarks made by tyndall: "assuredly no question of science ever stood so much in need of revision as this of the transmission of sound through the atmosphere. slowly but surely we mastered the question, and the further we advance, the more plainly it appeared that our reputed knowledge regarding it was erroneous from beginning to end." dr. mott then took up the other side of the question, and treated the same under the following heads: . agitation of the air. . mobility of the atmosphere. . resonance. . heat and velocity of the supposed sound waves. . decrease in loudness of sound. . the physical strength of the locust. . the barometric theory of sir wm. thomson. . elasticity and density of the air. . interference and beats. . the membrana tympani and the corti arches. under the first head dr. mott stated that all experiments and photographs made to establish the existence of sound waves simply referred to the necessary agitation of the air accompanying any disturbance, such as would of necessity be produced by a vibrating body, and had nothing to do directly with sound. he stated that in the edison telephone, sound was converted directly into electricity without vibrating any diaphragm at all, as attested to by edison himself. speaking of the mobility of the air, he said the particles were free to slip around and not practically be pushed at all, and that the greatest distance a steam whistle could affect the air would not exceed feet, and the waves would not travel more than or feet a second, while sound travels , feet a second. under heat and velocity of sound waves, dr. mott stated that newton found by calculating the exact relative density and elasticity of air that sound should travel only feet a second, while it was known to travel , feet a second. laplace, by a heat and cold theory, tried to account for the feet, and supposed that in the condensed portion of a sound wave heat was generated, and in the rarefied portion cold was produced; the heat augmenting the elasticity and therefore the sound waves, and the cold produced neutralizing the heat, thus kept the atmosphere at a constant temperature. dr. mott stated that when newton first pointed out this discrepancy of feet, the theory should have been dropped at once, and later on he showed the consequences of laplace's heat and cold theory. the great argument of the evening, and the one to which he attached the most importance, was that all scientists have spoken of the swift movement of the tuning fork, while in fact it moved , times slower than the hour hand of a clock and , , times slower than any clock pendulum ever constructed. since a pendulum cannot, according to the high authorities, produce sonorous air waves on account of its slow movement, dr. mott asks some one to enlighten him how a prong of a tuning fork going , , times slower could be able to produce them. he then showed that there was not the slightest similarity between the theoretical sound waves and water waves, and still they are spoken of as "precisely similar" and "essentially identical," and "move in exactly the same way." considerable merriment was occasioned when dr. mott showed what a locust stridulating in the air would be called upon to do if the present theory of sound were correct. he stated that a locust not weighing more than half a pennyweight, and that could not move an ounce weight, was supposed capable of setting cubic miles of atmosphere into vibration, weighing , , tons, so that it would be displaced times in one second, and any portion of the air could bend the human tympanic membrane once in and once out times in one second; and that , , people, nearly the whole population of the united states, could have their , pounds of tympanic membrane thus shaken by an insect that could not move an ounce weight to save its life; and that the , pounds of tympanic membrane of the entire population of the earth, amounting to , , , , who could conveniently stand in ¼ square miles, would be affected the same way by locusts stridulating in the air. according to the barometric theory of sir william thomson, he showed that a locust would have to add , , pounds to the weight of the atmosphere. under elasticity and density he stated that elasticity was a mere property of a body, and could not add one grain of force to that exercised by the locust, so as to assist it in performing such wonderful feats. under interference he showed that the law of interference is fallacious; that no such thing occurs; and that in the experiment with the siren to show such fact, the octave is produced which of necessity ought to be when the number of orifices are alternately doubled, and the same effect would be produced with one disk with double the number of holes. under the last head of his paper dr. mott proved that the membrana tympani was not necessary for good hearing, that in fact when it was punctured, a deaf man could in many cases be made to hear, and in fact it improved the hearing in general; the only reason why the tympanic membrane was not punctured oftener was that dust, heat, and cold were apt to injure the middle ear. in closing his paper dr. mott said that he would risk the fallacy of the current theory of sound on the argument advanced relating to the impossibility of the slow motion of a tuning fork to produce sonorous waves, and stated that he would retire if any one could show the fallacy of the argument; but if not, the wave theory must be abandoned as absurd and fallacious, as was the ptolemaic system of astronomy, which was handed down from age to age until copernicus and his aide de camp galileo gave to the world a better system. * * * * * the attock bridge. we give illustrations from _engineering_ of a bridge recently constructed across the indus river at attock, for the punjaub northern state railway. this bridge, which was opened on may , , was erected under the direction of mr. f.l. o'callaghan, engineer in chief, mr. h. johnson acting as executive engineer, and messrs. r.w. egerton and h. savary as assistants. [illustration: bridge over the river indus at attock: punjaub northern state railway, india.] the principal spans cover a length of about , feet. it will be seen from the diagram that there is a difference of nearly feet in the levels of high and low water. * * * * * the elasticity of metals. m. tresca has contributed to the _comptes rendus_ some observations on the effect of hammering, and the variation of the limit of elasticity of metals and materials used in the arts. he says that hitherto, in considering the deformation of solids under strain, two distinct periods, relative to their mechanical properties, have alone been recognized. these periods are of course the elastic limit and the breaking point. in the course of m. tresca's own experiments, however, he has found it necessary to consider, at the end of the period of alteration of elasticity, a third state, geometrically defined and describable as a period of fluidity, corresponding to the possibility of a continuous deformation under the constant action of the same strain. this particular condition is only realized with very malleable or plastic bodies; and it may even be regarded as characteristic of such bodies, since its absence is noticeable in all non-malleable or fragile bodies, which break without being deformed. it is already known that the period of altered elasticity for hard or tempered steel is much less than for iron. in the author showed that steel or iron rails that had acquired a permanent set were at the same time perfectly elastic up to the limit of the load which they had already borne. with certain bars the same result was renewed five times in succession; and thus their period of perfect elasticity could be successively extended, while the coefficient of elasticity did not appear to sustain any appreciable modification. this process of repeated straining, when there is an absence of a certain hammering effect, renders malleable bodies somewhat similar to those which are not malleable and brittle. there is an indication here of another argument against the testing of steam boilers by exaggerated pressures before use, which process has the effect of rendering the plates more brittle and liable to sudden rupture. m. tresca also protests against the elongation of metals under breaking strain tests being stated as a percentage of the length. the elongation is in all cases, chiefly local; and is therefore the same for a test piece inches or inches long, being confined to the immediate vicinity of the point of rupture. the indication of elasticity should rather be sought for in the reduction of the area of the bar at the point of rupture. this portion of the bar is otherwise remarkable for having lost its original condition. it is condensed in a remarkable manner, and has almost completely lost its malleability. the final rupture, therefore, is that of a brittle zone of the metal, of the same character that may be produced by hammering. if a test bar, strained almost to the verge of rupture, be annealed, it will stretch yet further before breaking; and, indeed, by successive annealings and stretchings, may be excessively modified in its proportions. * * * * * the harrington rotary engine. the chief characteristic or principle of this engine is the maintenance of an accurate steam and mechanical balance and the avoidance of cross pressure. the power is applied directly to the work, the only friction being that of the steel shaft in phosphor-bronze bearings. referring to the cuts, fig. shows the engine and an electric dynamo on the same shaft, all connecting mechanism being done away with, and pounding obviated. there are but two parts to the engine (two disks which supply the place of all the ordinary mechanism), both of which are large, solid, and durable. these disks have a bearing surface of several inches on each other, preventing the passage of steam between them--a feature peculiar to this engine. fig. represents an end elevation partly in section, showing the piston, a, and the abutment disk, b, in the position assumed in the instant of taking steam through a port from the valve-chamber, e. fig. is a vertical section through the center of fig. , showing the relations of the disks, c, and the abutment disks, b, and gear. the piston disks and gear are attached to the driving shaft, h, and the abutment disks and gear are attached to the shaft, k. these shafts, h and k, as above stated, run in taper phosphor-bronze bearings, which are adjustable for wear or other causes by the screw-caps, o. the whole mechanism is kept rigidly in place by the flanged hub, r, bolted securely to the cylinder head, f. these flanged heads project through the cylinder head, touching the piston disk, and thereby prevent any end motion of the shaft, h, or its attachments. the abutment disks and shaft are furnished with similar inwardly projecting flanged hubs, which are provided with a recess, i, fig. , on their periphery, located radially between the shaft, k, and the clearance space, j. into this recess steam is admitted--through an inlet in the cylinder head not shown in the cuts. by this means the shaft, k, is relieved of all side pressure. the exhaust-port, which is very large and relieves all back pressure, is shown at d. the pistons and disks are made to balance at the speed at which the engine is intended to run. the steam-valve, for which patent is pending, is new in principle. it has a uniform rotating motion, and, like the engine, is steam and mechanically balanced. the governor is located in the flywheel, and actuates the automatic cut-off, with which it is directly connected, without the intervention of an eccentric, in such a way as to vary the cut-off without changing the point of admission. by this means is secured uniformity of motion under variable loads with variable boiler pressure. it also secures the advantage resulting from high initial and low terminal pressure with small clearances and absence of compression, giving a large proportionate power and smooth action. expansion has been excellently provided for, the steam passing entirely around before entering the cylinder. these engines are mounted on a bed-plate which may be set on any floor without especial preparation therefor. the parts are all made interchangeable. a permanent indicator is provided which shows the exact point of cut-off. the steam-port is exceptionally large, being one-fourth of the piston area. reciprocating motion is entirely done away with. the steam is worked at the greatest leverage of the crank through the entire stroke. among the other chief advantages claimed for this engine are direct connection to the machinery without belts, etc., impossibility of getting out of line, uniform crank leverage, capacity for working equally well slow or fast, etc. it has but one valve, which is operated by gear from the shaft, as shown, traveling at one-half the velocity of the piston. [illustration: fig. .--the harrington rotary engine coupled to a dynamo.] with this engine a speed of , revolutions per minute is easily attainable, while, as a matter of fact and curiosity, a speed of , revolutions per minute has been obtained. an engine of this class was run at the illinois inter-state exposition at chicago for six weeks at a uniform speed of , revolutions per minute, furnishing the power for twenty-three electric arc lights, with a steam pressure not exceeding fifty-five pounds per square inch, and cutting off at from one-tenth to one-sixth of the stroke. it was taking steam from a large main-pipe, so there was no opportunity for an exact test of the amount of fuel used, but from a careful mathematical calculation it must have been developing one horse-power from three pounds of coal. the inventor claims that, as his engine works the steam expansively, even better results would have been obtained had the engine been furnished steam at pounds per square inch. [illustration: figs. and .--details of harrington engine.] the harrington rotary engine company, clinton street, chicago, are the owners and manufacturers. * * * * * in a can of peas sold in liverpool recently the public analyst found two grains of crystallized sulphate of copper, a quantity sufficient to injuriously affect human health. the defendant urged that the public insisted upon having green peas; and that artificial means had to be resorted to to secure the required color. * * * * * testing car varnishes. by d.d. robertson. at the master car-painters' convention, d.d. robertson, of the michigan central, read the following paper on the best method of testing varnishes to secure the most satisfactory results as to their durability, giving practical suggestions as to the time a car may safely remain in the service before being taken in for revarnishing: the subject which the association has assigned to me for this convention has always been regarded as important. there is no branch of the business which gives the painter more anxiety than the varnishing department. it is more susceptible to an endless variety of difficulties, and therefore needs more close and careful attention, than all other branches put together, and even with all the research and practical experience which has been given to the subject we are yet far from coming to a definite conclusion as to the causes of many of the unfavorable results. beauty and durability are what we aim at in the paint shop, and from my experience in varnish work we may have beauty without durability, but we have rarely durability without beauty, so that the fewer defects of any kind in our work caused by inferior material, inferior workmanship, or any other cause, it is more likely to be durable, and ought, therefore, to possess beauty. there are certain qualifications absolutely necessary to durability in varnish. the material of which it is made must be of the proper kind, pure and unadulterated; the manipulation in manufacturing must be correct as to time, quantities, temperature, handling, etc., and age is also necessary. the want of durability arising from the quality of the materials, or from the manner of manufacturing, the painter has no control over; but let me say here, that frequently a first-class varnish has been used upon a car, and after being in service for a short time it deadens, checks, cracks, chips, or flakes, and therefore shows a very poor record. the varnish is condemned, when in reality, had the varnish been applied under different circumstances and over different work, the result would have been good and the durability satisfactory. i am satisfied that in many cases first-class varnish has to bear the odium, when the root of the evil is to be found nearer the foundation. the leading varnish manufacturers of this country have expended large fortunes to secure the best skill and appliances, and, indeed, to do everything to bring their goods to perfection. their standing and respectability put them beyond suspicion, and their reputation is of too much value for them knowingly to put into the hands of large consumers an inferior article; and even when we have just cause to complain of the varnish, we ought to be charitable enough to attribute the mistake to circumstances beyond their control (for every kettleful is subjected to such circumstances), and not to charge them with using cheap or inferior material for the sake of gain. if the question which has been given me means to give some method of testing before using, i confess my inability to answer. for varnish to be pronounced "durable" must be composed of the materials to make it so, and to ascertain this, chemistry must be called in to test it. comparatively few painters understand chemistry sufficiently to analyze, and if they did, and found the material all that is necessary, the manipulation may have been defective, so as to injure its wearing qualities, and therefore i cannot suggest any way of pronouncing varnish durable before using it. as to the common custom of hanging out boards prepared and varnished to the exposure of the sun and weather for months does not seem to me to be the correct way of testing durability. it is true we may by this mode get some idea of wearing properties, but the most thorough and correct way is to put the varnish to the same exposure, the tear and wear, that it would have in the regular service on the road on which it is to run. cars while running are exposed to circumstances which boards on the wall are not subjected to. the cars under my charge run through two different countries and three different states, and therefore subjected to such a variety of climate and soil that the testing by stationary boards would completely fail to give the correct result. for example: i have placed two sample boards, prepared and varnished, and exposed them to all kinds of weather and to the constant and steady rays of the sun for an equal length of time, and both gave favorable results; and i have also put the same varnishes on a car and found very different results. one of the varnishes having some properties adapted to resist the friction caused by cinders, sand, and dust, and consequently not so liable to cut the surface, and therefore much more durable. the system which i adopted long ago, and to which i still adhere (not on account of "old fogyism," but for want of better), is as follows: i have two varnishes which i want to put into competition to test their relative merits. with varnish no. , i do the south half of the east end of the car and the east half of the south side of the car, the north half of the west end, and also the west end of the north side; this is also done with the same varnish. on the other half of the car varnish no. is put. thus you will see it is so placed that, should the car be turned at any time, both varnishes on each side will have the same exposure and circumstances to contend with. this i regard as the best method to test the durability of varnish. and again let me say that it would be wrong for me to argue that because the varnish which i use gives me the best results, therefore i would regard it the best for all to use. this would be wrong, inasmuch as we have a diversity of climates between maine and california, and between the extreme northern and southern states. the varnish which has failed to give me satisfaction may be most suitable for other parts of the union. as to the second part of my subject, "what length of time may a car safely remain in service before being taken in for revarnishing?" this must be regulated by the nature of the run and general treatment of the car while in service. through cars are frequently continuously on the road, and little or no opportunity can be had to attend to them while in service. such cars should be called in earlier than those which make shorter runs, and where ample time is allowed at both ends of the journey to be kept in order. and again, cars which are run nearest the engine cannot make so large a running record as those less exposed. some roads, for a variety of reasons which might be given, can run cars for months with less wear than others can run months. so that i hold that the master painter on every road should keep a complete and correct record of his cars, and have an opportunity to examine these at intervals and report their condition, in order to have them called in before they are too far gone for revarnishing. if this system was more frequently adopted, the rolling stock of our roads would be more attractive, and the companies would be the gainers. i cannot lay down a standard rule as to the exact time a car should remain in service before being called in for revarnishing, but i find as a general rule with the cars on the michigan central railroad that they should not exceed months' service, and new cars, or those painted from the foundation, should not be allowed to run over months the first year. by thus allowing a shorter period the first year the car will look better and wear longer by this mode of treatment. cars treated in this way can be kept running for six and seven years without repainting. * * * * * the fixation of magnetic phantoms. when we place a thin sheet of cardboard or glass upon a magnet and scatter iron filings over it, we observe the iron to take certain positions and trace certain lines which faraday has styled lines of magnetic force, or, more simply, lines of force. the figure, as a whole, which is thus formed constitutes a magnetic phantom. the forms of the latter vary with that of the magnet, the relative positions of the magnet and plate, etc. [illustration: method of fixing magnetic phantoms.] the whole space submitted to the influence of the magnet constitutes a _magnetic field_, which is characterized by the presence of these lines of force, and the study of which is of the most important character as regards electro-magnetic action and that of induction. in order to study these phantoms it is convenient to fix them so that they can be preserved, projected, or photographed. fig. shows how they may be fixed. to effect this, we cover the plate with a layer of mucilage of gum arabic, allow the latter to harden, and then place the plate over the magnet. next, iron filings are scattered over the surface by means of a small sieve, and, when the curves are well developed,[ ] the surface is moistened by the aid of an ordinary vaporizer. the layer of gum arabic thus becomes softened and holds the iron filings so that the particles cannot change position. when the gum has hardened again, the magnet is removed, and the phantom is fixed. [footnote : the curves are obtained by striking the plate lightly with a glass rod.] we thus have a tangible representation of the magnetic field produced by the magnet in the plane of the glass plate or sheet of paper. the number of these lines, or their density, is at every point proportional to the intensity of the field, and the curves that are traced show their direction. to finish the definition of the field, it remains to determine the direction of these lines of force. such direction is, by definition, and conventionally, that in which the north pole of a small magnetic needle, free to move in the field, would travel. it results from this definition that the lines of force issue from the north pole of a magnet and re-enter the south pole, since the north pole of a magnet repels the north pole of a needle, and _vice versa._ these considerations relative to the direction and intensity of the magnetic field are of the highest importance for the physical theory of magneto-electric machines. the following is another method of fixing phantoms, as employed by prof. bailie, of the industrial school of physics and chemistry of the city of paris. he begins by forming the phantom, in the usual way, upon paper prepared with ferrocyanide, and exposes it to daylight for a sufficient length of time. the filings form a screen which is so much the more perfect in proportion as it is denser, and, after fixation, there is obtained a negative phantom, that is to say, one in which the parts where the field is densest have remained white. the same processes of fixation apply equally well to galvanic phantoms, that is to say, to the galvanic fields produced by the passage of a current in a conductor, and which consists of analogous lines of force. the processes may be employed very efficaciously and with certainty of success.--_la nature._ * * * * * a chippendale sideboard. [illustration: a chippendale sideboard.] our illustration this week is of a unique and handsome piece of chippendale work. the outline is elegant, and the scrollings delicate. the pedestals are peculiar in their form, the panels being carved in draperies, etc. in the frieze are two drawers, with grotesque heads forming the handles. the back is fitted with shaped glass and surmounted by an eagle. the whole forms a very characteristic piece of work of the period, having been made about - . as our readers are aware, thomas chippendale published his book of designs in , with the object of promoting good french design in this field of art. this piece of furniture was sold at auction lately for guineas.--_building news._ * * * * * liquefaction of the elementary gases. by jules jamin, of the institute of france. the earlier experiments of mm. cailletet and raoul pictet in the liquefaction of gases, and the apparatus by means of which they performed the process, were described in the _popular science monthly_, march and may, . the experiments have since been continued and improved upon by mm. cailletet and pictet, and others, with more complete results than had been attained at the time the first reports were published, and with the elucidation of some novel properties of gases, and the disclosure of relations, previously not well understood, between the gaseous and the liquid condition. the experiments of faraday, in the compression of gases by the combined agency of pressure and extreme cold, left six gases which still refused to enter into the liquid state. they were the two elements of the atmosphere (oxygen and nitrogen), nitric oxide, marsh-gas, carbonic oxide, and hydrogen. many new experiments were tried before the principle that governs the change from the gaseous to the liquid, or from the liquid to the gaseous form was discovered. aime sank manometers filled with air into the sea till the pressure upon them was equal to that of four hundred atmospheres; berthelot, by the expansion of mercury in a thermometer tube, succeeded in exerting a pressure of seven hundred and eighty atmospheres upon oxygen. both series of experiments were without result. m. cailletet, having fruitlessly subjected air and hydrogen to a pressure of one thousand atmospheres, came to the conclusion that it was impossible to liquefy those gases at the ordinary temperature by pressure alone. previously it had been thought that the obstacle to condensing gases by pressure alone lay in the difficulty of obtaining sufficient pressure, or in that of finding a vessel suitable for manipulation that would be capable of resisting it. m. cailletet's thought led to the discovery of another fundamental property of gases. the experiments of despretz and regnault had shown that the scope of mariotte's law (that the volume of gases increases or diminishes inversely as the pressure upon them) was limited, and that its limits were different with different substances. andrews confirmed the observations of these investigators, and extended them. compressing carbonic acid at ° c. ( ° fahr.), he found that the rate of diminution in volume increased more rapidly than mariotte's law demanded, and at a progressive rate. at fifty atmospheres the gas all at once assumed the liquid form, became very dense, and fell to the bottom of the vessel, where it remained separated from its vapor by a clearly defined surface, like that which distinguishes water in the air. experimenting in the same way with the gas at a higher temperature ( ° c. or ° fahr.), he found that the same result was produced, but more slowly; and it seemed to be heralded in advance by a more rapid diminution in volume previous to the beginning of the change, which continued after the process had been accomplished; as if an anticipatory preparation for the liquid state were going on previous to the completion of the change. performing the experiment again at ° c. ( ° fahr.), the anticipatory preparation and the after-continuation of the contraction were more marked, and, instead of a separate and distinct liquid, wavy and mobile striæ were perceived on the sides of the vessel as the only signs of a change of state which had not yet been effected. at temperatures above ° c. ( ° fahr.), there were neither striæ nor liquefaction, but there seemed to be a suggestion of them, for, under a particular degree of pressure, the density of the gas was augmented, and its volume diminished at an increasing rate. the temperature of ° c. ( ° fahr.) is, then, a limit, marking a division between the temperatures which permit and those which prevent liquefaction; it is the critical point, at which is defined the separation, for carbonic acid, between two very distinct states of matter. below this point, the particular matter may assume the aspect of a liquid; above it, the gas cannot change its appearance, but enters into the opposite constitution from that of a liquid. generally, a liquid has considerably greater density than its vapor. but, if a vessel containing both is heated, the liquid experiences a dilatation which is gradually augmented till it equals and even exceeds that of the gas; whence, of course, an equal volume of the liquid will weigh less and less. on the other hand, a constantly larger quantity of vapor is formed, which accumulates above the liquid and becomes heavier and heavier. now if the density of the vapor increases, and that of the liquid diminishes, they will reach a point, under a suitable temperature, when they will be the same. there will then be no reason for the liquid to sink or the vapor to rise, or for the existence of any line of separation between them, and they will be mixed and confounded. they will no longer be distinguishable by their heat of constitution. it is true that, in passing into the state of a vapor, a liquid absorbs a great deal of latent heat, but that is employed in scattering the molecules and keeping them at a distance; and there will be none of it if the distance does not increase. we are then, at this stage of our experiments, in the presence of a critical point, at which we do not know whether the matter is liquid or gaseous; for, in either condition, it has the same density, the same heat of constitution, and the same properties. it is a new state, the gaso-liquid state. an experiment of cagniard-latour re-enforced this explanation of the phenomena. heating ether in closed vessels to high temperatures, he brought it to a point where the liquid could be made wholly to disappear, or to be suddenly reformed on the slightest elevation or the slightest depression of temperature accordingly as it was raised just above or cooled to just below the critical point. the discovery of these properties suggested an explanation of the failure of previous attempts to liquefy air. air at ordinary low temperatures is in the gaso-liquid condition, and its liquefaction is not possible except when a difference exists between the density of the vapor and that of the liquid greater than it is possible to produce under any conditions that can exist then. it was necessary to reduce the temperature to below the critical point; and it was by adopting this course that mm. cailletet and raoul pictet achieved their success. the rapid escape of the compressed gas itself from a condition of great condensation at an extremely low temperature was employed as the agent for producing a greater degree of cold than it had been possible before to obtain. m. cailletet used oxygen escaping at - ° c. from a pressure of three hundred atmospheres; m. raoul pictet, the same gas escaping at - ° from a pressure of three hundred and twenty atmospheres; and both obtained oxygen and nitrogen, and m. pictet hydrogen, in what they thought was a liquid, and possibly even in a solid form. still, it could not be asserted that hydrogen and the elements of the air had been completely liquefied. these gases had not yet been seen collected in the static condition at the bottom of a tube and separated from their vapors by the clearly defined concave surface which is called a _meniscus._ the experiments had, however, proved that liquefaction is possible at a temperature of below - ° c. (- ° fahr.). to make the process practicable, it was only necessary to find sufficiently powerful refrigerants; and these were looked for among gases that had proved more refractory than carbonic acid and protoxide of nitrogen. m. cailletet selected ethylene, a hydrocarbon of the same composition as illuminating gas, which, when liquefied by the aid of carbonic acid and a pressure of thirty-six atmospheres, boils at - ° c. (- ° fahr.). m. wroblewski, of cracow, who had witnessed some of m. cailletet's experiments, and obtained his apparatus, and m. olzewski, in association with him, also experimented with ethylene, and had the pleasure of recording their first complete success early in april, . causing liquid ethylene to boil in an air-pump vacuum at - ° c., they were able to produce a temperature of - ° c. (- ° fahr.), the lowest that had ever been observed. oxygen, having been previously compressed in a glass tube, became a permanent liquid, with a clearly defined meniscus. it presented itself, like the other liquefied gases, under the form of a transparent and colorless substance, resembling water, but a little less dense. its critical point was marked at - ° c. (- ° fahr.), below which the liquid could be formed, but never above it; while it boiled rapidly at - ° c. (- ° fahr.). a few days afterward, the polish professors obtained the liquefaction of nitrogen, a more refractory gas, under a pressure of thirty-six atmospheres, at - ° c. (- ° fahr.). long, difficult, and expensive operations were required to produce this result, for the extreme degree of cold it demanded had to be produced by boiling large quantities of ethylene in a vacuum. m. cailletet devised a cheaper process, by employing another hydrocarbon that rises from the mud of marshes, and is called _formene_. it is less easily liquefied than ethylene, but for that very reason can be boiled in the air at a lower temperature, or at - °c. (- ° fahr.); and at this temperature nitrogen and oxygen can be liquefied in a bath of formene as readily as sulphurous acid in the common freezing mixture. mm. cailletet, wroblewski, and olzewski have continued their experiments in liquefaction, and acquired increased facility in the handling of liquid ethylene, formene, atmospheric air, oxygen, and nitrogen. m. olzewski was able to report to the french academy of sciences, on the st of july, , that by placing liquefied nitrogen in a vacuum he had succeeded in producing a temperature of - °c. (- ° fahr.), under which hydrogen was liquefied. contrary to the suppositions founded on the metallic behavior of this element, that it would present the appearance of a molten metal, like mercury, the liquid had the mobile behavior and the transparency of the hydrocarbons. * * * * * examination of fats. the methods employed up to the present in examination of fats, animal and vegetable, are mere reactions lacking general application; scattered throughout the literature, and doubtful with regard to reliability, they are of little or no value to the experimenter--an approximate quantitative examination even of a simple mixture being exceedingly difficult if not impossible, since the qualitative composition of fatty substances is the same, and the separation of the nearer components impracticable. the object of analysis consisted in estimating the accompanying impurities of fat, as, resin, albuminoids, and pigments. the nature of these substances depends on the mode of extraction and preservation of the fat, and are subject in the course of time to alteration. the only reaction based upon the chemical constitution of fat is produced by treatment of oleic or linoleic acid with nitrous acid, which therefore is of some value in the examination of drying oils. of general application are the methods which correspond to the chemical constitution of fats, and thus determine the relative quantity of the components; advantage can then be derived from qualitative reactions, inasmuch as they further affirm the result of the quantitative test, or dispel any doubt with regard to the correctness of the result. the principal methods which comply with these demands have been carefully studied by hueble for the purpose of discovering a process of general application; methods founded on the determination of density, freezing, and melting point were compared with those dependent on the solubility of fatty substances in glacial acetic acid or a mixture of alcohol and acetic acid; also the method of hehner for testing of butter, the determination of glycerine and oleic acid, and at length the process of saponification. nearly all fats contain members belonging to one of the three series of fatty acids, _e.g._, acids of the type of acetic acid (stearic and palmitic acids); such as are derivatives of acrylic acid (oleic and erucic acids); and such as are homologues of tetrolic acid (linoleic acid). it is likely that the relative quantity of each of these acids is variable, with regard to the same fat, within definite limits, and changes with the nature of the fatty substance. the groups of fatty acids are distinguished by a characteristic deportment toward halogens; while members of the first series are indifferent to haloids, those of the second and third class combine readily, without suffering substitution, with two respectively four atoms of a haloid. in view of this behavior the first series is termed saturated, the second and third that of unsaturated acids. addition of halogen to one of the unsaturated acids yields on subsequent examination an invariable quantity of the former, representing two or four atoms, according to one or the other of unsaturated groups; and as the molecular weights of fatty acids are unequal, the percentage quantity of halogen will be found varying with regard to members belonging to the same series. the amount of iodine absorbed by some of the fatty acids is illustrated by the following items: hypogallic acid, c_{ }h_{ }o_{ }, combines with . grammes. iodine. oleic acid, c_{ }h_{ }o_{ } " " . " " erucic acid, c_{ }h_{ }o_{ } " " . " " ricinoleic acid, c_{ }h_{ }o_{ } " " . " " linoleic acid, c_{ }h_{ }o_{ } " " . " " of the halogens employed in the examination, iodine is preferable to either chlorine or bromine; it acts but slowly at ordinary, but energetically at elevated temperatures. the reagents are solution of mercury iodo-chloride prepared by dissolving of grms. iodine, c.c. alcohol of per cent., and of grms. mercury chloride in an equal measure of the same solvent; both liquids are filtered and united; a standard solution of sodium hyposulphite produced by digestion of grms. of the dry salt with liter water and titration with iodine solution; solution of potassium iodide of : ; chloroform, and finally a solution of starch. the above solution of mercury iodo-chloride acts on both free unsaturated acids and glycerides, producing addition products. for testing a sample of . to . grm. of a liquid, and from . to . grm. of a solid fat being used, which is dissolved in c.c. chloroform and treated with c.c. mercury iodo-chloride solution run into it from a burette, if the liquid appear opalescent a further measure of chloroform is introduced, while the amount of mercury iodo-chloride must be such as to produce a brownish coloration of the chloroform for two subsequent hours. the excess of iodine is determined, on addition of from to c.c. potassium iodide solution and c.c. distilled water, by means of caustic soda. from a burette divided into . c.c. a solution of caustic soda is poured with continual gyration of the flask into the tinged liquid, and the percentage of combined iodine ascertained by difference; for this purpose c.c. of mercury iodo-chloride are tested, on introduction of a solution of potassium iodide and starch, previously to its use as reagent. adulteration of solid or semi-liquid fats, especially lard, butter, and tallow, with vegetable oils are readily detected by this method, since the latter yield on examination a high percentage of iodine. animal fats, absorb comparatively less halogen than vegetable fats, and the power to combine with iodine increases with the transition from the solid to the liquid state, and attains its maximum with vegetable oils--the method being adapted to the examination of fat mixtures containing glycerides and free saturated fatty acids, provided that substances which under similar conditions combine with iodine are absent. these conditions are fulfilled with regard to the examination of animal fats and soap. ethereal oils are also acted upon by iodine; the reaction proceeds similar to that observed in ordinary fat mixtures. alcoholic mercury iodo-chloride can probably be used with success in synthetical chemistry, as it allows determination of the free affinities of the molecule and conversion of unsaturated compounds into saturated chlorine-iodo addition products.--_rundschau._ * * * * * notes on nitrification.[ ] [footnote : a paper by r. warington, read before the chemical section of the british association at montreal.] by r. warington. in the following brief notes i propose to consider in the first place the present position of the theory of nitrification, and next to give a short account of the results of some recent experiments conducted in the rothamsted laboratory. _the theory of nitrification._--the production of nitrates in soils, and in waters contaminated with sewage, are facts thoroughly familiar to chemists. it is also well known that ammonia, and various nitrogenous organic matters, are the materials from which the nitric acid is produced. till the commencement of it was generally supposed that this formation of nitrates from ammonia or nitrogenous organic matter was the result of simple oxidation by the atmosphere. in the case of soil it was imagined that the action of the atmosphere was intensified by the condensation of oxygen in the pores of the soil; in the case of waters no such assumption was possible. this theory was most unsatisfactory, as neither solutions of pure ammonia, nor of any of its salts, could be nitrified in the laboratory by simple exposure to air. the assumed condensation of oxygen in the pores of the soil also proved to be a fiction as soon as it was put by schloesing to the test of experiment. early in , two french chemists, messrs. schloesing and müntz, published preliminary experiments showing that nitrification in sewage and in soils is the result of the action of an organized ferment, which occurs abundantly in soils and in most impure waters. this entirely new view of the process of nitrification has been amply confirmed both by the later experiments of schloesing and müntz, and by the investigations of other chemists, among which are those by myself conducted in the rothamsted laboratory. the evidence for the ferment theory of nitrification is now very complete. nitrification in soils and waters is found to be strictly limited to the range of temperature within which the vital activity of living ferments is confined. thus nitrification proceeds with extreme slowness near the freezing-point, and increases in activity with a rise in temperature till ° is reached; the action then diminishes, and ceases altogether at °. nitrification is also dependent on the presence of plant-food suitable for organisms of low character. recent experiments at rothamsted show that in the absence of phosphates no nitrification will occur. further proof of the ferment theory is afforded by the fact that antiseptics are fatal to nitrification. in the presence of a small quantity of chloroform, carbon bisulphide, salicylic acid, and apparently also phenol, nitrification entirely ceases. the action of heat is equally confirmatory. raising sewage to the boiling-point entirely prevents its undergoing nitrification. the heating of soil to the same temperature effectually destroys its nitrifying power. finally, nitrification can be started in boiled sewage, or in other sterilized liquid of suitable composition, by the addition of a few particles of fresh surface soil or a few drops of a solution which has already nitrified; though without such addition these liquids may be freely exposed to filtered air without nitrification taking place. the nitrifying organism has been submitted as yet to but little microscopical study; it is apparently a micrococcus. it is difficult to conceive how the evidence for the ferment theory of nitrification could be further strengthened; it is apparently complete in every part. although, however, nearly the whole of this evidence has been before the scientific public for more than seven years, the ferment theory of nitrification can hardly be said to have obtained any general acceptance; it has not indeed been seriously controverted, but neither has it been embraced. in hardly a single manual of chemistry is the production of saltpeter attributed to the action of a living ferment existing in the soil. still more striking is the absence of any recognition of the evidence just mentioned when we turn to the literature and to the public discussions on the subjects of sewage, the pollution of river water, and other sanitary questions. the oxidation of the nitrogenous organic matter of river water is still spoken of by some as determined by mere contact with atmospheric oxygen, and the agitation of the water with air as a certain means of effecting oxidation; while by others the oxidation of nitrogenous organic matter in a river is denied, simply because free contact with air is not alone sufficient to produce oxidation. how much light would immediately be thrown on such questions if it were recognized that the oxidation of organic matter in our rivers is determined solely by the agency of life, is strictly limited to those conditions within which life is possible, and is most active in those circumstances in which life is most vigorous. it is surely most important that scientific men should make up their minds as to the real nature of those processes of oxidation of which nitrification is an example. if the ferment theory be doubted, let further experiments be made to test it, but let chemists no longer go on ignoring the weighty evidence which has been laid before them. it is partly with the view of calling the attention of english and american chemists to the importance of a decision on this question that i have been induced to bring this subject before them on the present occasion. i need hardly add that such results as the nitrification of sewage by passing it through sand, or the nitrification of dilute solutions of blood prepared without special precaution, are no evidence whatever against the ferment theory of nitrification. if it is to be shown that nitrification will occur in the absence of any ferment, it is clear that all ferments must be rigidly excluded during the experiments; the solutions must be sterilized by heat, the apparatus purified in a similar manner, and all subsequent access of organisms carefully guarded against. it is only experiments made in this way that can have any weight in deciding the question. leaving now the theory of nitrification, i will proceed to say a few words, first, as to the distribution of the nitrifying organism in the soil; secondly, as to the substances which are susceptible of nitrification; thirdly, upon certain conditions having great influence on the process. _the distribution of the nitrifying organism in the soil._--three series of experiments have been made on the distribution of the nitrifying organism in the clay soil and subsoil at rothamsted. advantage was taken of the fact that deep pits had been dug in one of the experimental fields for the purpose of obtaining samples of the soil and subsoil. small quantities of soil were taken from freshly-cut surfaces on the sides of these pits at depths varying from inches to feet. the soil removed was at once transferred to a sterilized solution of diluted urine, which was afterward examined from time to time to ascertain if nitrification took place. these experiments are hardly yet completed; the two earlier series of solutions have, however, been examined for eight and seven months respectively. in both these series the soil taken from inches, inches, and inches from the surface has been proved to contain the nitrifying organism by the fact that it has produced nitrification in the solutions to which it was added; while in twelve distinct experiments made with soil from greater depths no nitrification has yet occurred, and we must therefore conclude that the nitrifying organism was not present in the samples of soil taken. the third series of experiments has continued as yet but three months and a half; at present no nitrification has occurred with soil taken below inches from the surface. it would appear, therefore, that in a clay soil the nitrifying organism is confined to about inches from the surface; it is most abundant in the first inches. it is quite possible, however, that in the channels caused by worms, or by the roots of plants, the organism may occur at greater depths. in a sandy soil we should expect to find the organism at a lower level than in clay, but of this we have as yet no evidence. the facts here mentioned are in accordance with the microscopical observations made by koch, who states that the micro-organisms in the soils he has investigated diminish rapidly in number with an increasing depth; and that at a depth of scarcely meter the soil is almost entirely free from bacteria. some very practical conclusions may be drawn from the facts now stated. it appears that the oxidation of nitrogenous matter in soil will be confined to matter near the surface. the nitrates found in the subsoil and in subsoil drainage waters have really been produced in the upper layer of the soil, and have been carried down by diffusion, or by a descending column of water. again, in arranging a filter bed for the oxidation of sewage, it is obvious that, with a heavy soil lying in its natural state of consolidation, very little will be gained by making the filter bed of considerable depth; while, if an artificial bed is to be constructed, it is clearly the top soil, rich in oxidizing organisms, which should be exclusively employed. _the substances susceptible of nitrification._--the analyses of soils and drainage waters have taught us that the nitrogenous humic matter resulting from the decay of plants is nitrifiable; also that the various nitrogenous manures applied to land, as farmyard manure, bones, fish, blood, rape cake, and ammonium salts, undergo nitrification in the soil. illustrations of many of these facts from the results obtained in the experimental fields at rothamsted have been published by sir j.b. lawes, dr. j.h. gilbert, and myself, in a recent volume of the _journal_ of the royal agricultural society of england. in the rothamsted laboratory, experiments have also been made on the nitrification of solutions of various substances. besides solutions containing ammonium salts and urea, i have succeeded in nitrifying solutions of asparagine, milk, and rape cake. thus, besides ammonia, two amides, and two forms of albuminoids have been found susceptible of nitrification. in all cases in which amides or albuminoids were employed, the formation of ammonia preceded the production of nitric acid. mr. c.f.a. tuxen has already published in the present year two series of experiments on the formation of ammonia and nitric acids in soils to which bone-meal, fish-guano, or stable manure had been applied; in all cases he found the formation of ammonia preceded the formation of nitric acid. as ammonia is so readily nitrifiable, we may safely assert that every nitrogenous substance which yields ammonia when acted upon by the organisms present in soil is also nitriflable. _certain conditions having great influence in the process of nitrification._--if we suppose that a solution containing a nitrifiable substance is supplied with the nitrifying organism, and with the various food constituents necessary for its growth and activity, the rapidity of nitrification will depend on a variety of circumstances: . the degree of concentration of the solution is important. nitrification always commences first in the weakest solution, and there is probably in the case of every solution a limit of concentration beyond which nitrification is impossible. . the temperature has great influence. nitrification proceeds far more rapidly in summer than winter. . the presence or absence of light is important. nitrification is most rapid in darkness; and in the case of solutions, exposure to strong light may cause nitrification to cease altogether. . the presence of oxygen is of course essential. a thin layer of solution will nitrify sooner than a deep layer, owing to the larger proportion of oxygen available. the influence of depth of fluid is most conspicuous in the case of strong solutions. . the quantity of nitrifying organism present has also a marked effect. a solution seeded with a very small amount of organism will for a long time exhibit no nitrification, the organism being (unlike some other bacteria) of very slow growth. a solution receiving an abundant supply of the ferment will exhibit speedy nitrification, and strong solutions may by this means be successfully nitrified, which with small seedings would prove very refractory. the speedy nitrification which occurs in soil (far more speedy than in experiments in solutions under any conditions yet tried) is probably owing to the great mass of nitrifying organisms which soil contains, and to the thinness of the liquid layer which covers the soil particles. . the rapidity of nitrification also depends on the degree of alkalinity of the solution. nitrification will not take place in an acid solution; it is essential that some base should be present with which the nitric acid may combine; when all available base is used up, nitrification ceases. it appeared of interest to ascertain to what extent nitrification would proceed in a dilute solution of urine without the addition of any substance save the nitrifying ferment. as urea is converted into ammonium carbonate in the first stage of the action of the ferment, a supply of salifiable base would at first be present, but would gradually be consumed. the result of the experiment showed that only one-half the quantity of nitric acid was formed in the simple urine solution as in similar solutions containing calcium and sodium carbonate. the nitrification of the urine had evidently proceeded until the whole of the ammonium had been changed into ammonium nitrate, and the action had then ceased. this fact is of practical importance. sewage will be thoroughly nitrified only when a sufficient supply of calcium carbonate, or some other base, is available. if, instead of calcium carbonate, a soluble alkaline salt is present, the quantity must be small, or nitrification will be seriously hindered. sodium carbonate begins to have a retarding influence on the commencement of nitrification when its amount exceeds milligrammes per liter, and up to the present time i have been unable to produce an effective nitrification in solutions containing . gramme per liter. sodium hydrogen carbonate hinders far less the commencement of nitrification. ammonium carbonate, when above a certain amount, also prevents the commencement of nitrification. the strongest solution in which nitrification has at present commenced contained ammonium carbonate equivalent to milligrammes of nitrogen per liter. this hinderance of nitrification by the presence of an excess of ammonium carbonate effectually prevents the nitrification of strong solutions of urine, in which, as already mentioned, ammonium carbonate is the first product of fermentation. far stronger solutions of ammonium chloride can be nitrified than of ammonium carbonate, if the solution of the former salt is supplied with calcium carbonate. nitrification has in fact commenced in chloride of ammonium solutions containing more than two grammes of nitrogen per liter. the details of the recent experiments, some of the results of which we have now described, will, it is hoped, shortly appear in the _journal_ of the chemical society of london. harpenden, july . * * * * * aniline dyes in dress materials. by professor charles o'neill. twenty-eight years ago mr. perkin discovered the first of the aniline dyes. it was the shade of purple called mauve, and the chief agent in its production was bichromate of potash. this salt is not actively poisonous, and no one thought of attributing injurious properties to materials dyed with the aniline mauve. next in chronological order came magenta red. it was first made from aniline by the agency of mercurial salts, and afterward by that form of arsenic known to chemists as arsenic acid. the fact that this at one time fashionable color was prepared by means of an arsenical compound was spread through the country in a very impressive manner by the great trial as to whether the patent was valid or not, all turning upon the expression in the specification of "dry arsenic acid," and the disputes of scientists whether this expression meant arsenic acid with or without water. the public mind had been for some time previously exercised and alarmed by accounts of sickness and debility caused by arsenical paper-hangings; it was, therefore, easy for pseudo scientists to create an opinion that the magenta dye must be also poisonous, and that persons wearing materials dyed with this color were liable to absorb arsenic and suffer from its action. ever since there have been, at intervals, statements more or less circumstantial, that individuals have suffered from wearing materials dyed with some of the artificial dyes. at the present time these statements are emphasized by the exhibition at the healtheries of models of skin diseases said to be actually produced by the wearing of dyed garments. whether it be true or not that any form of skin disease has been produced by the wearing of dyed articles of clothing is simply a question of evidence, and there is evidence enough to show that individuals have experienced ill effects who have worn clothing dyed with artificial colors. but, as far as we know, there is an entire want of any evidence that will satisfactorily show that the inconvenience suffered by wearers of these dyed goods has been owing to the dyeing material. years must elapse before chemists or physicians can hope to become thoroughly informed of the physiological action produced by the cutaneous absorption of the thousands of new products which the ingenuity and industry of technological chemists have made available for the manufacture of colors; they are also new to science, most of them very complex in their constitution, and so dissimilar to previously studied compounds used by the dyer, that it may be said we have nearly everything to learn concerning their action upon the human economy. with respect to dyed woolen and silk goods it is almost entirely a question as to the innocence or otherwise of the coloring matter itself, which in nine cases out of ten is an organic body containing no mineral matter of any sort, and not requiring the assistance of any mordant to enable it to dye. considerations of arsenic, or antimony, or mercury existing in the dyed stuffs are absolutely excluded. in a few cases the dyestuff is a zinc compound, and zinc in small traces may possibly be fixed by the material, but this metal is not known to be actively noxious. textiles made from fibers of animal origin do not require, and as a rule do not tolerate, the addition of any metal in dyeing with the artificial colors, and if the manufacture of the color require the use of a metal, such as arsenic, which by unskillfulness or carelessness is left in it when delivered to the dyer, the tendency of the animal fiber is to reject it. but the case with regard to textiles made from vegetables fibers is quite different; upon materials made from cotton, flax, jute, or other fiber of the vegetable kingdom, the new aniline colors cannot be fixed without the assistance of other bodies acting the part of mordants. some of these bodies are actively poisonous in their nature, and introduce a possible element of danger to the wearer of the dyed article. for many years, almost the only method of dyeing cotton goods with the aniline colors consisted in a preliminary steeping in sumac or tannic acid, followed by a passage in some suitable compound of tin, and subsequent dyeing in the coloring matter. sumac and tin have been used for two hundred years or more as the dyer's basis for a considerable number of shades of color from old dye-stuffs; there never has been the least suspicion that there was anything hurtful in colors so dyed. sumac or tannic acid, in combination with alumina, may be held to be equally inoffensive; now it is a fact that the great bulk of cotton goods are dyed with the aniline colors by the agency of these harmless chemicals. but of late years the dyers of certain goods, and the calico printers generally, have found an advantage in the use of tartar emetic, and other compounds of antimony, to fix aniline colors; besides this, some colors are fixed in calico printing by means of an arsenical alumina mordant; it need not be mentioned that antimony, as well as arsenic, is, when administered internally, an active poison in even small quantities, and that externally both are injurious under certain conditions. an alarmist would require nothing further than this statement to feel himself justified in attributing everything bad to fabrics so colored; but the practical dyer or calico printer knows that though he employs these poisonous bodies in his business, and that some portion of them does actually accompany the dyed material in its finished state, not only is the quantity excessively small, but that it is in such a state of combination as to be completely inert and innoxious. in the case of tartar emetic, it is the tannate of antimony which remains upon the cloth, a compound of considerable stability, and almost perfectly insoluble in water; in the case of a few colors fixed by the arsenical alumina mordant, the arsenic is in an insoluble state of combination with the alumina, in fact, the poisons are in the presence of their antidotes, and not even the most scrupulous manufacturer has any fear that he is turning out goods which can be hurtful to the wearer. persons quite unacquainted with the process of dyeing are apt to think that goods are dyed by simply immersing them in a colored liquid and then drying them with all the color on them and all that the color contains; they do not know that in all usual cases of dyeing a careful washing in a plentiful supply of water is the final process in the dye-house, and that nothing remains upon the cloth which can be washed out by water, the color being retained by a sort of attraction or affinity between it and the fiber, or mordant on the fiber. dyeing is not like painting or even the printing or staining of paper for hangings, where the vehicle and color in its entirety is applied and remains. it follows, therefore, that many chemicals used in dyeing have only a transitory use, and are washed away completely--such as oil of vitriol, much used in woolen dyeing--and that of others only a very minute quantity is finally left on the cloth, as is the case in antimony and arsenic in cotton dyeing and printing. there is evidently among working dyers, as among all other classes, an unknown amount of carelessness, ignorance, and stupidity, from which employers are constantly suffering in the shape of spoiled colors and rotted cloth. it is not for us to say that the public may not at times have to suffer also from neglect of the most common treatments which should remove injurious matters from dyed goods; what can be said is, that if the dyeing processes for aniline colors be followed out with ordinary care and intelligence, it is extremely improbable that anything left in the material should be injurious to human health.--_manchester textile recorder._ * * * * * case of resuscitation and recovery after apparent death by hanging. by ernest w. white, m.b. lond., m.r.c.p., senior assistant medical officer to the kent lunatic asylum; associate, late scholar, of king's college, london. the following case, from its hopelessness at the outset, yet ultimate recovery under the duly recognized forms of treatment, is of such interest as to demand publicity, and will afford encouragement to others in moments of doubt. m.a. s----, aged fifty-three, was admitted into the kent lunatic asylum at chartham on oct. , , suffering from melancholia, the duration of which was stated to have been three months. she had several times attempted suicide by drowning and strangulation. she was on admission ordered a mixture containing morphia and ether thrice daily, to allay her distress. on oct. she attempted suicide by tying a stocking, which she had secreted about her person, round her neck. shortly afterward, with similar intent, she threw herself downstairs. on jan. , , she attempted to strangle herself with her apron. on the th of november following, at p.m. she evaded the attendants, and made her way to the bath-room of of no. ward, the door of which had been left unfastened by an attendant. she then suspended herself from a ladder there by means of portions of her dress and underclothing tied together. a patient of no. ward discovered her suspended from the ladder eight minutes after she had last seen her in the adjoining watercloset, and gave the alarm. the woman was quickly cut down, and the medical officers summoned. in the interval cold affusion was resorted to by the attendant in charge, but the patient was to all appearances dead. the junior assistant medical officer, mr. j. reynolds salter, m.b. lond., arrived after about three minutes, and at once resorted to artificial respiration by the silvester method. a minute or so later the medical superintendent and myself joined him. at this time the condition of the patient was as follows: the face presented the appearance known as facies hippocratica: the eyeballs were prominent, the corneæ glassy, the pupils widely dilated, not acting to light, and there was no reflex action of the conjunctivæ; the lips were livid, the tongue tumefied, but pallid, the skin ashy pale, the cutaneous tissues apparently devoid of elasticity. there was an oblique depressed mark on the neck, more evident on the left side; the small veins and capillaries of the surface of the body were turgid with coagulating blood the surface temperature was extremely low. she was pulseless at the wrists and temples. there was no definite beat of the heart recognizable by the stethoscope. there was absolute cessation of all natural respiratory efforts, complete unconsciousness, total abolition of reflex action and motion, and galvanism with the ordinary magneto-electric machine failed to induce muscular contractions. the urine and fæces had been passed involuntarily during or immediately subsequent to the act of suspension. as the stethoscope revealed that but a small amount of air entered the lungs with each artificial inspiration, the tongue was at once drawn well forward, and retained in that position by an assistant, with the result that air then penetrated to the smaller bronchi. inspiration and expiration were artificially imitated about ten times to the minute. in performing expiration the chest was thoroughly compressed. the lower extremities were raised, and manual centripetal frictions freely applied. in the intervals of these applications warmth to the extremities was resorted to. about ten minutes from the commencement of artificial respiration we noticed a single weak spasmodic contraction of the diaphragm, the feeblest possible effort at natural respiration. simultaneously, very distant weak reduplicated cardiac pulsations, numbering about to the minute, became evident to the stethoscope. the reduplication implied that the two sides of the heart were not acting synchronously, owing to obstruction to the pulmonary circulation induced by the asphyxiated state. artificial respiration was steadily maintained, and during the next half hour spasmodic contractions of the diaphragm occurred at gradually diminishing intervals, from once in three minutes to three or four times a minute. these natural efforts were artificially aided as far as possible. at : p.m. natural respiration was fairly though insufficiently established, the skin began to lose its deadly hue, and titillation of the fauces caused weak reflex contractions. flagellation with wet towels was now freely resorted to, and immediately the natural efforts at respiration were increased to twice their previous number. the administration of a little brandy and water by the mouth failed, as the liquid entered the larynx. ammonia was applied to the nostrils, and the surface temperature was increased by warm applications and clothing. at p.m. artificial respiration was no longer necessary. the heart sounds then numbered to the minute, the right and left heart still acting separately. a very small radial pulse could also be felt. at : p.m. the woman was put to bed, warmth of surface maintained, and hot coffee and beef-tea given in small quantities. great restlessness and jactitation set in with the renewal of the circulation in the extremities. an enema of two ounces of strong beef-tea was administered at p.m. the amount of organic effluvium thrown off by the lungs on the re-establishment of respiration was very great and tainted the atmosphere of the room and adjoining ward. the pupils, previously widely dilated, began to contract to light at p.m. imperfect consciousness returned at p.m. the following day (dec. ), and about an hour later she vomited the contents of the stomach (bread, etc., taken on nov. ). small quantities of beef-tea were given by the mouth during the night. at a.m. air entered the lungs freely, and there were no symptoms of pulmonary engorgement beyond slight basic hypostasis; the pulse remained at , and the heart sounds reduplicated; she was semiconscious, very drowsy, in a state of mental torpor, with confused ideas when roused, and she complained of rheumatic-like pains all over her. the temperature was . °; the facial expression more natural; the tongue remained somewhat swollen and sore; she was no longer restless; she took tea, beef-tea, milk, etc., well; the functions of the secreting organs were being restored; she perspired freely; had micturated; the mucous membrane of the mouth was moist, and there was a tendency to tears without corresponding mental depression. the patient was ordered a mixture of ether and digitalis every four hours. on december the pulse was , and the heart sounds reduplicated. the following day she was given bromide of potassium in place of the ether in the digitalis mixture. on the th the pulse was ; reduplication gone. on the th the pulse was , and the temperature fell with the pulse rate. she was well enough to get into the ward for a few hours. her memory, especially for recent events, was at that time greatly impaired. on the th she still complained of muscular pains like those of rheumatism. apart from that, she was enjoying good bodily health. a curious fact in connection with this case is that since this attempt at suicide she has steadily improved mentally, has lost her delusions, is cheerful, and employs herself usefully with her needle. she converses rationally, and tells me she recollects the impulse by which she was led to hang herself, and remembers the act of suspension; but from that time her memory is a blank, until two days subsequently, when her husband came to see her, and when she expressed great grief at having been guilty of such a deed. her bodily health is now (june , ) more robust than formerly, and she is on the road to mental convalescence. _remarks._--the successful issue of this case leads me to draw the following inferences: . that in cases of suspended animation similar to the above there is no symptom by which apparent can be distinguished from real death. . that in artificial respiration alone do we possess the means of restoring animation when life is apparently extinct from asphyxia, and that, with the tongue drawn well forward and retained there by the hand or an elastic band, the silvester method is complete and effective. . that artificial respiration may be necessary for two hours or more before the restoration of adequate natural efforts, and that the performance of the movements ten times to the minute is amply sufficient, and produces a better result than a more rapid rate. . that galvanism, ammonia to the nostrils, cold affusion, and stimulants by the mouth are practically useless in the early stage. . that on the re-establishment of the reflex function we possess a powerful auxiliary agent in flagellation with wet towels, etc. . that centripetal surface frictions and the restoration of the body temperature by warm applications aid recovery. . that the heart, if free from organic disease, has great power of overcoming the distention of its right cavities and the obstruction to the pulmonary circulation, although its action may for a time be seriously deranged, as evidenced by reduplication of its sounds. . that when the heart's action remains excessively feeble, and the right and left heart fail to contract synchronously, it would be justifiable to open the external jugular vein. . that during recovery the lungs are heavily taxed in purifying the vitiated blood, as shown by the excessive amount of organic impurities exhaled. . that restlessness and jactitation accompany the restoration of nerve function, and that vomiting occurs with returning consciousness. . that pains like those of rheumatism are complained of for some days subsequently, these probably resulting from the sudden arrest of nutrition in the muscles. chartham, near canterbury. --_lancet._ * * * * * the inventors' institute. the twenty-second session of the inventors' institute was opened on october , the chair being taken by vice-admiral j.h. selwyn, one of the vice-presidents, at the rooms of the institute, lonsdale chambers, chancery lane, london. the chairman, in delivering the inaugural address, said that in the absence of their president, the duke of manchester, it became his duty to open the session of . the institute having been established in , this was their twenty-second anniversary. at the time of its establishment a greater number of members were rapidly enrolled than they could now reckon, although a large number had joined since the commencement of the present year. in a considerable amount of enthusiasm on the part of inventors had arisen, from the fact that at that time the leading journals had advocated the views of certain manufacturers as to sweeping away the patent laws, enacted anew in , and with them the sole protection of the inventive talent and industry of the nation. this naturally caused much excitement and interest among those chiefly concerned, and a very numerous body of gentlemen associated themselves together and formed an institute for the purpose mainly of resisting the aggression and inculcating views more in accordance with true principles, as well as for explaining what were the true relations of inventive genius to the welfare of the state. he hoped to be able to show strong reasons for this action, and for energetically following it up in the future. although on that evening there were many visitors present besides the members of the institute, yet he thought the subject could be shown to be of such national importance that it might justly engage the attention of any assembly of englishmen, to whatever mode of thought they might belong. the institute had persistently done its work ever since its formation. sometimes it had failed to make itself heard, at others it had been more successful in so doing; but the net result of its labors--and he did not fear to claim it as mainly due to those labors--had been to propagate and spread abroad a fact and a feeling entirely opposed to the false doctrines previously current on the subject, namely, that among our most valuable laws were those which could excite the intelligence and reward the labors of the inventors of all nations. there were still those who wished to see the patent laws swept away, but their numbers had dwindled into a miserable minority, composed mainly of manufacturers who were so curiously short-sighted as not to see that all improvement in manufactures must come from inventive talent, or those who, still more blind, could not perceive that property created by brains was certainly not a monopoly, and deserves protection quite as much as any other form of possession, in order that it may be developed by capital. he need scarcely waste time in pointing out the fallacy of refusing to pay for the seed corn of industrial pursuits, for that fallacy, bit by bit, had been completely swept away, and last year the labors of the institute had been so far crowned with success that the president of the board of trade, in his place in parliament, announced his conviction that "inventors were the creators of trade, and ought to be encouraged and not repressed." such a conviction, forced home in such a quarter, ought to have produced a great and beneficial change in the legislation on the subject, and the hopes of inventors were that this would surely be the case; but when the bill appeared these hopes were considerably depressed, and now, after a year's experience of the working of the changed law, scarcely any benefit appears to have been obtained, beyond the meager concession that the heavy payments demanded, for an english patent may be made in installments instead of lump sums. against this infinitesimal concession had to be set a number of disabilities which did not formerly exist, such as compulsory licenses, which disinclined the capitalist to invest in inventions, attempts to assimilate the provisional specification to the complete, or to restrict the latter within the terms of the former, attempts to separate the parts of an invention, and thus increase the number of patents required to protect it, and many other minor annoyances which would take too much time to explain fully. it was true that there was some extension of the time for payment--some such locus penitentiæ as would be accorded to any debtor by any creditor in the hope of getting the assets; but the promised spirit of encouragement to inventors was not to be found in the bill; it was still a boon which must be earnestly sought by the institute. he had said that the concessions granted were almost infinitesimal, yet a result had been obtained, surprisingly confirmatory of the views always advocated by the institute as to the potentiality of the inventive talent of this nation were it released from its shackles. while in former years the highest number of patents taken out had slowly risen to the number of five to six thousand per annum, in the year now expiring it had bounded to more than three times five thousand--had at one leap reached an equality with the patents of the united states, where only £ ($ ) was paid for a patent for seventeen years, instead of £ , as in great britain, for a term of fourteen years. if in the future we could hope to persuade the legislators to be content with no heavier tax than in the united states had yielded a heavy surplus over expenses of a well-conducted patent office, he did not fear to assert that the number of patents taken out in this country would again be trebled, and that trade and industry would be correspondingly animated and developed. the result of the wiser patent law of the united states had been to flood our markets with well-manufactured yet cheap articles from that country which might have been equally well made by our artisans at home had invention not been subject to such heavy restrictions, and had technical skill been equally sure of its reward. the business of the institute in the future was not to rest satisfied with the proposition of mr. chamberlain, but to lead him or his successors forward by logical and legitimate means toward the necessary corollary of that proposition. if inventors were indeed the creators of trade, then the president of the board of trade was bound to see, not only that they were not prevented from creating trade, but that they received every facility in performing their work. hence all exertions should be used to convince the chancellor of the exchequer that a less tax may produce a greater income: to persuade the legal authorities that this description of property, of all others, most deserves the protection of the law. inherited direct from the giver of all good gifts, no person had been dispossessed of anything he previously owned, and the wealth of humanity might be indefinitely increased by means of it. not many mighty, not many noble, received this gift, but it was the inexhaustible heritage of the humble, it was the rich reward of the intelligent of all races that peopled the earth. to whomsoever given, this gift was intended to contribute to the health and the wealth of the human race, for the bringing into existence new products, for their utilization for the encouragement of the general intelligence of the nations, and for the lightening of the burdens of the poor. it would also cause technical education to be more highly valued as a means to an end--for true inventive genius was never so likely to succeed as when it passed from the summit of the known to the confines of the possible, when, having learnt and appreciated what predecessors had accomplished, it went earnestly to work to solve the next problem, to remove the next obstacle on the path which to them had proved insurmountable. more beneficial than any other change whatever in our legislation would be a full and cordial recognition, a complete and efficient protection, of property created by thought. then the humblest individual in the land might have confidence that he could call into existence property not inferior in value to that of the richest landowner, the most successful merchant, or the most wealthy manufacturer, in the whole world. as an instance of this admiral selwyn mentioned two prominent cases arising out of the pursuit of two widely differing branches of knowledge, in the one case by an outsider, in the other by a specialist. he referred to sir h. bessemer, one of his valued colleagues in the vice-presidency of the institute, and mr. perkins, the discoverer of aniline dyes. in each of these instances, whatever might have been the results to the inventors, and he hoped they had been satisfactory, a sum which might be estimated at twenty millions sterling annually, constantly on the increase, and never before existing, had been added to the income-tax-paying wealth of the country. with such a result arising from the development of only two inventions, he thought it would be seen that he must be a most ignorant, foolish, or obstinate chancellor of the exchequer who would refuse to allow such property to be created by requiring heavy preliminary payments, or in any way discourage or fail to encourage to the utmost of his power the creation of property which was capable of producing such a result--a result which he would in vain seek for did he rely on landed property alone, since this, in the hands of whomsoever it might be, never could largely increase in extent, and was subject at this moment to serious depreciation in tax-paying power. the exertion of intelligence, combined with a sense of security in its pecuniary results, was in itself opposed to loose notions of proprietary rights, and tended to diminish that coveting of neighbors' goods which was the fertile source of vice and crime, and which was capable of breaking down the strongest and most wealthy community if indulged, till at last society was resolved into its elements, and when nothing else was left as property, man, the savage, coveted the scalp of his fellow man, and triumphed over a lock of hair torn from his bleeding skull. invention was an ennobling pursuit, and was, even among those who were not also handworkers, a means of employment which never left dull or idle hours, while to the handworker it meant more, for it offered the most ready means of rising among his fellows, and, where invention received proper protection, of securing a competence for old age or ill health. not only, as he had before said, did the results of invention cause no loss to any other individual, unless by displacing inferior methods of working, but in most instances some distinct benefit arose to the whole human race, and unless this was the case the patented invention failed to obtain recognition, soon died out, and left the field clear for others to occupy. he regretted that so few results had been obtained from the patent bill of last year, but he would briefly refer to some of the changes thought desirable by inventors and by the council of the institute. no one could deem it desirable, it could scarcely be thought reasonable, that an englishman who was called upon to pay in the united states £ for a valid patent for seventeen years should be still obliged in his own country to pay £ for a less term of a patent which does not convey anything but a right to go to law. it was also not reasonable to pretend by a deed to convey a proprietary right while reserving the power to grant compulsory licenses, which must tend to destroy the value of such proprietary right. it was a reproach to legislative perspicacity that the grantee of a patent should be obliged to accept the view of the state, the grantor, as to the value of the invention to the nation, and also that any other method of proceeding to upset a patent, once granted, should be allowed than a suit for revocation to the crown, on the ground of error, such revocation if obtained not to prejudice the granting anew, with the old date, of a valid patent for the parts of the invention which are not proved to be anticipated at the trial. there are many other points which could not be referred to on the present occasion, but he might say that the duty of the council would be to press them forward until the capitalist could consider patented property at least as sound an investment as any other. so might the wealth of the nation be largely increased, and the sense of justice between man and man be more fully inculcated. in the united states inventors were able at once to secure the favorable attention of capitalists, because there the whole business of the patent office was to assist the inventor to obtain a valid--and, as far as possible, an indisputable--patent. even so small an article as a pair of pliers, one of the most familiar of tools, had been proved to be capable of patented improvement. formerly these were always made to open and close at an angle which precluded their holding any object grasped by them with the desirable rigidity. a clever workman invented a means of producing this effect by the application of a parallel motion. he probably went to the office at washington, was referred to a certain room in a certain corridor, and there found a gentleman whose business it was to know all about the patents for such tools. by his aid he eliminated from his patent all anticipatory matter, and issued from the office with a valid patent, which, developed by capital, had supplied all the trades which employ such instruments with a better means of accomplishing their work, had employed capital and labor with remunerative results in producing the pliers, and had added one more to the little things which create trade for his country. this was a typical instance of the way in which invention was encouraged in america. why should it be otherwise here? for many years literary property had received a protection which was yet to be desired for patented invention. not only for fourteen years, but for the duration of a man's life, was that kind of brain property protected, and even after his death his heirs still continued to derive benefit from it. should a romance or a poem be deemed more worthy of reward than the labors of those inventors to whom he had referred, and which certainly produced far greater and more abiding advantage to the nation? to secure a due appreciation of the whole importance of invention, no other means could be adopted than that which the institute had been formed to secure, namely, the union of inventors, not only of one nation, but of the whole world. the international character of the subject had been recognized by the institute, and they had never neglected any opportunities of pressing that view of the subject, which had at last obtained some recognition from our government. no great result could, however, be expected from a congress where inventors, not lawyers or patent agents, still less officials trained in a vicious routine, formed the majority. it might be hoped that next year there would arise an opportunity for such a congress, and that the institute would do its best to improve the occasion. there never had been a time when england more required the creation of new industries. our agriculturists had signally failed to hold their own in the face of unlimited competition, and the food of the nation no longer came from within. but if that were the case, then some means must be found of paying for the food imported from abroad, and this could only be done by constant improvement in manufactures, or some change by which we might sell some of our other productions at a profit if the food could not be produced but at a loss. here invention might fitly be called to aid, but could only respond if all restrictions were removed and every facility granted. capital must be induced to consider that home investments are more remunerative and not less secure than any others, and this could only be done by adding to the security of the property proposed for investment. he had referred to the unlimited nature of the property created by invention, and they would infer that if properly protected there was equally no limit to the capital that could be profitably employed in developing such property. the institute did not exist solely or even mainly for the purpose of advocating the claims of inventors to consideration, either individually or collectively, but for the great object of forcing home upon the convictions of the people the fact that at the very foundation of the wealth and prosperity of every nation lies the intelligence, the skill, the honesty, and the self-denial of its sons. if, when these were exercised, for want of wise legislation such virtues failed to secure their due reward, they sought a more genial clime, and that nation which had undervalued them sank to rise no more; or, if the error were acknowledged, and too late the course was reversed, found itself already outstripped in the race of progress, and could slowly, if ever, regain its lost position. finally he urged the inventors of england to rally round the institution in all their strength, and thus secure the objects of which he had striven, however feebly, to point out the importance. if they did so, this institution would take a rank second to no other in the empire: and while acknowledging that the interests of the inventor must always be subordinate to the welfare of the state, he asserted that the two were inseparable, and that in no other way could the latter and principal result be so completely secured as by according a due consideration to the former. * * * * * the new central school at paris. we present herewith, from _l'illustration_, views of the amphitheater, and first and second year laboratories of the new central school at paris. [illustration: the new central school at paris.] the amphitheater does not perceptibly differ from those of other schools. it consists of a semicircle provided with rows of benches, one above another, upon which the pupils sit while listening to lectures and taking notes thereof. several blackboards, actuated by hydraulic motors, serve for demonstration by the professor, who, if need be, will be enabled, thanks to the electricity and gas put within his reach, to perform experiments of various kinds. electricity is brought to him by wires, just as water and gas are by pipes. it will always be possible for him to support the theory that he is explaining by experiments which facilitate the comprehension of it by the pupils. the amphitheater is likewise provided with a motor which furnishes the professor with power whenever he has recourse to a mechanical application. it will not be possible for the pupils to have their attention distracted by what is going on outside of the amphitheater, since the architect has taken the precaution to use ground glass in the windows. [illustration: the new central school at paris.] as regards the laboratories, it is allowable to say that they constitute the first great school of experimental chemistry in france. the first year laboratory consists of a series of tables, provided with evaporating hoods, at which a series of pupils will study general chemistry experimentally. electricity, and gas and water cocks are within reach of each operator, and all the deleterious emanations from the acids that are used or are produced in studying a body will escape through the hoods. the third year laboratory is designed for making commercial analyses. these latter are made by either dry or wet way. the first method employs water chiefly as a vehicle, and alkaline solutions as reagents. the second employs reagents in a dry state, and the action of which requires lamp and furnace heat. the furnaces employed in the new school are like those almost exclusively used industrially for the analysis of ores. the tables upon which analyses by dry way are made are large enough to allow sixteen pupils to work. [illustration: the new central school at paris.] analyses by wet way are made upon tables, with various sorts of vessels. along with water, gas, and electricity, the pupils have at their disposal a faucet from whence they may draw the hydrosulphuric acid which is so constantly used in laboratory operations. the architect of the new school is mr. denfer. * * * * * [nature.] researches on the origin and life-histories of the least and lowest living things. by rev. w.h. dallinger, ll. d. to all who have familiarized themselves, even cursorily, with modern scientific knowledge, it is well known that the mind encounters the _infinite_ in the contemplation of minute as well as in the study of vast natural phenomena. the farthest limit we have reached, with the most gigantic standard of measurement we could well employ, in gauging the greatness of the universe, only leaves us with an overwhelming consciousness of the awful greatness--the abyss of the infinite--that lies beyond, and which our minds can never measure. the indefinite has a limit somewhere; but it is not the indefinite, it is the measureless, the infinite, that vast extension forces upon our minds. in like manner, the immeasurable in minuteness is an inevitable mental sequence from the facts and phenomena revealed to us by a study of the _minute_ in nature. the practical divisibility of matter disclosed by modern physics may well arrest and astonish us. but biology, the science which investigates the phenomena of all living things, is in this matter no whit behind. the most universally diffused organism in nature, the least in size with which we are definitely acquainted, is so small that fifty millions of them could lie together in the one-hundredth of an inch square. yet these definite living things have the power of locomotion, of ingestion, of assimilation, of excretion, and of enormous multiplication, and the material of which the inconceivably minute living speck is made is a highly complex chemical compound. we dare not attempt a conception of the minuteness of the ultimate atoms that compose the several simple elements that thus mysteriously combine to form the complex substance and properties of this least and lowliest living thing. but if we could even measure these, as a mental necessity, we are urged indefinitely on to a minuteness without conceivable limit, in effect, a minuteness that is beyond all finite measure or conception. so that, as modern physics and optics have enabled us not to conceive merely, but to actually realize, the vastness of spatial extension, side by side with subtile tenuity and extreme divisibility of matter, so the labor, enthusiasm, and perseverance of thirty years, stimulated by the insight of a rare and master mind, and aided by lenses of steadily advancing perfection, have enabled the student of life-forms not simply to become possessed of an inconceivably broader, deeper, and truer knowledge of the great world of visible life, of which he himself is a factor, but also to open up and penetrate into a world of minute living things so ultimately little that we cannot adequately conceive them, which are, nevertheless, perfect in their adaptations and wonderful in their histories. these organisms, while they are the least, are also the lowliest in nature, and are to our present capacity totally devoid of what is known as organic structure, even when scrutinized with our most powerful and perfect lenses. now these organisms lie on the very verge and margin of the vast area of what we know as living. they possess the essential properties of life, but in their most initial state. and their numberless billions, springing every moment into existence wherever putrescence appeared, led to the question, how do they originate? do they spring up _de novo_ from the highest point on the area of _not-life_, which they touch? are they, in short, the direct product of some yet uncorrelated force in nature, changing the dead, the unorganized, the not-living, into definite forms of life? now this is a profound question, and that it is a difficult one there can be no doubt. but that it is a question for our laboratories is certain. and after careful and prolonged experiment and research the legitimate question to be asked is, do we find that, in our laboratories and in the observed processes of nature now, the not-living can be, without the intervention of living things, changed into that which lives? to that question the vast majority of practical biologists answer without hesitancy, _no_, we have no facts to justify such a conclusion. prof. huxley shall represent them. he says: "the properties of living matter distinguish it absolutely from all other kinds of things;" and, he continues, "the present state of our knowledge furnishes us with no link between the living and the not-living." now let us carefully remember that the great doctrine of charles darwin has furnished biology with a magnificent generalization; one indeed which stands upon so broad a basis that great masses of detail and many needful interlocking facts are, of necessity, relegated to the quiet workers of the present and the earnest laborers of the years to come. but it is a doctrine which cannot be shaken. the constant and universal action of variation, the struggle for existence, and the "survival of the fittest," few who are competent to grasp will have the temerity to doubt. and to many, that lies within it as a doctrine, and forms the fibre of its fabric, is the existence of a continuity, an unbroken stream of unity running from the base to the apex of the entire organic series. the plant and the animal, the lowliest organized and the most complex, the minutest and the largest, are related to each other so as to constitute one majestic organic whole. now to this splendid continuity practical biology presents no adverse fact. all our most recent and most accurate knowledge confirms it. but _the_ question is, does this continuity terminate now in the living series, and is there then a break--a sharp, clear discontinuity, and beyond, another realm immeasurably less endowed, known as the realm of not-life? or does what has been taken for the clear-cut boundary of the vital area, when more deeply searched, reveal the presence of a force at present unknown, which changes not-living into the living, and thus makes all nature an unbroken sequence and a continuous whole? that this is a great question, a question involving large issues, will be seen by all who have familiarized themselves with the thought and fact of our times. but we must treat it purely as a question of science; it is not a question of _how_ life _first_ appeared upon the earth, it is only a question of whether there is any natural force _now_ at work building not-living matter into living forms. nor have we to determine whether or not, in the indefinite past, the not-vital elements on the earth, at some point of their highest activity, were endowed with, or became possessed of, the properties of life. [illustration: fig. ] on that subject there is no doubt. the elements that compose protoplasm--the physical basis of all living things--are the familiar elements of the world without life. the mystery of life is not in the elements that compose the vital stuff. we know them all, we know their properties. the mystery consists _solely_ in _how_ these elements can be so combined as _to acquire_ the transcendent properties of life. moreover, to the investigator it is not a question of _by what means_ matter dead--without the shimmer of a vital quality--became either slowly or suddenly possessed of the properties of life. enough for us to know that whatever the power that wrought the change, that power was competent, as the issue proves. but that which calm and patient research has to determine is whether matter demonstrably _not living_ can be, without the aid of organisms already living, endowed with the properties of life. judged of hastily, and apart from the facts, it may appear to some minds that an origin of life from not-life, by sheer physical law, would be a great philosophical gain, an indefinitely strong support of the doctrine of evolution. if this were so, and, indeed, so far as it is believed to be so, it would speak and does speak volumes in favor of the spirit of science pervading our age. for although the vast majority of biologists in europe and america accept the doctrine of evolution, they are almost unanimous in their refusal to accept as in any sense competent the reputed evidence of "spontaneous generation;" which demonstrates, at least, that what is sought by our leaders in science is not the mere support of hypotheses, cherished though they may be, but the truth, the uncolored truth, from nature. but it must be remembered that the present existence of what has been called "spontaneous generation," the origin of life _de novo_ to-day, by physical law, is by no means required by the doctrine of evolution. prof. huxley, for example, says: "if all living beings have been evolved from pre-existing forms of life, it is enough that a single particle of protoplasm should _once_ have appeared upon the globe, as the result of no matter what agency; any further independent formation of protoplasm would be sheer waste." and why? we may ask. because one of the most marvelous and unique properties of protoplasm, and the living forms built out of it, _is the power_ to multiply indefinitely and for ever! what need, then, of spontaneous generation? it is certainly true that evidence has been adduced purporting to support, if not establish, the origin in dead matter of the least and lowest forms of life. but it evinces no prejudice to say that it is inefficient. for a moment study the facts. the organisms which were used to test the point at issue were those known as _septic_. the vast majority of these are inexpressibly minute. the smallest of them, indeed, is so small that, as i have said, fifty millions of them, if laid in order, would only fill the one-hundredth part of a cubic inch. many are relatively larger, but all are supremely minute. now, these organisms are universally present in enormous numbers, and ever rapidly increasing in all moist putrefactions over the surface of the globe. take an illustration prepared for the purpose, and taken direct from nature. a vessel of pure drinking water was taken during the month of july at a temperature of deg. f., and into it was dropped a few shreds of fish muscle and brain. it was left uncovered for twelve hours; at the end of that time a small blunt rod was inserted in the now somewhat opalescent water, and a minute drop taken out and properly placed on the microscope, and, with a lens just competent to reveal the minutest objects, examined. the field of view presented is seen in fig. , a. but--with the exception of the dense masses which are known as zoogloea or bacteria, fused together in living glue--the whole field was teeming with action; each minute organism gyrating in its own path, and darting at every visible point. the same fluid was now left for sixteen hours, and once more a minute drop was taken and examined with the same lens as before. the field presented to the eye is depicted in fig. , b, where it is visible that while the original organism persists yet a new organism has arisen in and invaded the fluid. it is a relatively long and beautiful spiral form, and now the movement in the field is entrancing. the original organism darts with its vigor and grace, and rebounds in all directions. but the spiral forms revolving on their axes glide like a flight of swallows over the ample area of their little sea. ten hours more elapsed and, without change of circumstances, another drop was taken from the now palpably putrescent fluid. the result of examination is given in fig. , c, where it will be seen that the first organism is still abundant, the spiral organism is still present and active, but a new and oval form, not a bacterium, but a _monad_, has appeared. and now the intensity of action and beauty of movement throughout the field utterly defy description, gyrating, darting, spinning, wheeling, rebounding, with the swiftness of the grayling and the beauty of the bird. finally, at the end of another eight to sixteen hours, a final "dip" was taken from the fluid, and under the same lens it presented as a field what is seen in fig. , d, where the largest of the putrefactive organisms has appeared and has even more intense and more varied movements than the others. now the question before us is, "how did these organisms arise?" the water was pure; they were not discoverable in the fresh muscle of fish. yet in a dozen hours the vessel of water is peopled with hosts of individual forms which no mathematics could number! how did they arise? from universally diffused eggs, or from the direct physical change of dead matter into living forms? twelve years ago the life-histories of these forms were unknown. we did not know biologically how they developed. and yet with this great deficiency it was considered by some that their mode of origin could be determined by heat experiments on the adult forms. roughly, the method was this: it was assumed that nothing vital could resist the boiling point of water. fluids, then, containing full-grown organisms in enormous multitudes, chiefly bacteria, were placed in flasks, and boiled for from five to ten minutes. while they were boiling the necks of the flasks was hermetically closed; and the flask was allowed to remain unopened for various periods. the reasoning was: "boiling has killed all forms of vitality _in_ the flask; by the hermetical sealing nothing living can gain subsequent access to the fluid; therefore, if living organisms do appear when the flask is opened, they must have arisen in the dead matter _de novo_ by spontaneous generation, but if they do never so arise, the probability is that they originate in spores or eggs." now it must be observed concerning this method of inquiry that it could never be final; it is incompetent by deficiency. its results could never be exhaustive until the life-histories of the organisms involved were known. and further, although it is a legitimate method of research for partial results, and was of necessity employed, yet it requires precise and accurate manipulation. a thousand possible errors surround it. it can only yield scientific results in the hands of a master in physical experiment. and we find that when it has secured the requisite skill, as in the hands of prof. tyndall, for example, the result has been the irresistible deduction that living things have never been seen to originate in not-living matter. then the ground is cleared for the strictly biological inquiry, how do they originate? to answer that question we must study the life histories of the minutest forms with the same continuity and thoroughness with which we study the development of a crayfish or a butterfly. the difficulty in the way of this is the extreme minuteness of the organisms. we require powerful and perfect lenses for the work. happily during the last fifteen years the improvement in the structure of the most powerful lenses has been great indeed. prior to this time there were english lenses that amplified enormously. but an enlargement of the image of an object avails nothing, if there be no concurrent disclosure of detail. little is gained by expanding the image of an object from the ten-thousandth of an inch to an inch, if there be not an equivalent revelation of hidden details. it is in this revealing quality, which i shall call _magnification_ as distinct from _amplification_, that our recent lenses so brilliantly excel. it is not easy to convey to those unfamiliar with objects of extreme minuteness a correct idea of what this power is. but at the risk of extreme simplicity, and to make the higher reaches of my subject intelligible to all, i would fain make this plain. but to do so i must begin with familiar objects, objects used solely to convey good relative ideas of minute dimension. i begin with small objects with the actual size of which you are familiar. all of us have taken a naked eye view of the sting of the wasp or honey bee; we have a due conception of its size. this is the scabbard or sheath which the naked eye sees.[ ] within this are two blades terminating in barbed points. the point of the scabbard more highly magnified is presented, showing the inclosed barbs. one of the barbs, looked at on the barbed edge, is also seen. now these two barbed stings are tubes with an opening in the end of the barb. each is connected with the tube of the sac, c. this is a reservoir of poison, and d is the gland by which it is secreted. now i present this to you, not for its own sake, but simply for the comparison, a comparison which struck the earliest microscopists. here is the scabbard carefully rendered. one of the stings is protruded below its point, as in the act of stinging; the other is free to show its form. now the actual length of this scabbard in nature was the _one-thirtieth_ of an inch. i have taken the point, c, of a fine cambric sewing needle, and broken it off to slightly less than the one-thirtieth of an inch, and magnified it as the sting is magnified. now here we obtain an instance of what i mean by magnification. the needle point is not merely bigger, unsuspected details start into view. the sting is not simply enlarged, but all its structure is revealed. nor can we fail to note that the _finish_ of art differs from that of nature. the homogeneous gloss of the needle disappears under the fierce scrutiny of the lens, and its delicate point becomes furrowed and riven. but nature's finish reveals no flaw, it remains perfect to the last. [footnote : a magnified image of the bee's sting was projected on the screen.] we may readily amplify this. the butterflies and moths of our native lands we all know; most of us have seen their minute eggs. many are quite visible to the unaided eye; others are extremely minute. a gives the egg of the small white butterfly;[ ] b, that of the small tortoiseshell; c, that of the waved umber moth; d, that of the thorn moth; e, that of the shark moth; at f we have the delicate egg of the small emerald butterfly, and at g an american skipper; and finally, at h, the egg of a moth known as mania maura. in all this you see a delicacy of symmetry, structure, and carving, not accessible to the eye, but clearly unfolded. we may, from our general knowledge, form a correct notion of the average relation in size existing between butterflies and their eggs; so that we can compare. now there is a group of extremely minute, insect-like forms that are the parasites of birds. many of them are just plainly visible to the naked eye, others are too minute to be clearly seen, and others yet again wholly elude the unaided sight. the epizoa generally lodge themselves in various parts of the plumage of birds; and almost every group of birds becomes the host of some specific or varietal form with distinct adaptations. there is here seen a parasite that secretes itself in the inner feathers of the peacock, this is a form that attacks the jay, and here is one that secretes itself beneath the plumage of the partridge. [footnote : a series of the eggs of butterflies were then shown, as were the objects successively referred to, but not here reproduced.] now these minute creatures also deposit eggs. they are placed with wonderful instinct in the part of the plumage and the part of the feather which will most conserve their safety; and they are either glued or fixed by their shape or by their spine in the position in which they shall be hatched. i show here a group of the eggs of these minute creatures. i need not call your attention to their beauty; it is palpable. but i am fain to show you that, subtle and refined as that beauty is, it is clearly brought out. the flower-like beauty of the egg of the peacock's parasite, the delicate symmetry and subtle carving of the others, simply entrance an observer. note then that it is not merely _enlarged_ specks of form that we are beholding, but such true magnifications of the objects as bring out all their subtlest details. and it is _this_ quality that must characterize our most powerful lenses. i am almost compelled to note in passing that the _beauty_ of these delicate and minute objects must not be considered _an end_--a purpose--in nature. it is not so. the form is what it is because it _must be_ so to serve the end for which the egg is formed. there is not a superfluous spine, not a useless petal in the floral egg, not an unneeded line of chasing in the decorated shell. it is shaped beautifully because its shape is needed. in short, it is nature's method; the identification of beauty and use. but to resume. we may at this point continue our illustrations of the analytical power of moderate lenses by a beautiful instance. we are indebted to albert michael, of the linnean society of england, for a masterly treatise on a group of acari, or _mites_, known as the _oribatidæ_. many of these he has discovered. the one before you is a full grown nymph of what is known as a _palmicinctum_. it is deeply interesting as a form; but for us its interest is that it is minute, being only a millimeter in length. but it repeatedly casts the dorsal skin of the abdomen. each skin is bordered by a row of exquisite scales; and then successive rows of these scales persist, forming a protection to the entire organism. mark then that we not only reveal the general form of the nymph, but the lens reveals the true structure of the scales, not enlargement merely, but detail. the egg of the organism, still more magnified, is also seen. to vary our examples and still progress. we all know the appearance and structure of chalk. the minute foraminifera have, by their accumulated tests, mainly built up its enormous masses. but there is another chalk known as barbados earth; it is silicious, and is ultimately composed of minute and beautiful skeletons such as those which, enormously magnified, you now see. these were the glassy envelopes which protected the living speck that dwelt within and built it. they are the minutest of the radiolaria, which peopled in inconceivable multitudes the tertiary oceans; and, as they died, their minute skeletons fell down in a continuous rain upon the ocean bed, and became cemented into solid rock which geologic action has brought to the surface in barbados and many other parts of the earth. if a piece of this earth, the size of a bean, be boiled in dilute acid and washed, it will fall into powder, the ultimate grains of which are such forms as these which you see. the one before you is an instance of exquisite refinement of detail. the form from which the drawing of the magnified image was made was extremely small--a mere white speck in the strongest light upon a black ground. but you observe it is not a speck of form merely enlarged. it is not merely beauty of outline made bigger. but there is--as in the delicate group you now see--a perfect opening up of otherwise absolutely invisible details. we may strengthen this evidence in favor of the analytical power of our higher lenses by one more _familiar_ example, and then advance to the most striking illustration of this power which our most perfect and powerful lenses can afford. i fear that may be taking too much for granted to assume that every one in an audience like this has seen a human flea! most, however, will have a dim recollection or suggestive instinct as to its size in nature. nothing striking is revealed by this amount of magnification excepting the existence of breathing pores or spiracles along the scale armor of its body. but there is a trace of structure in the terminal ring of the exo-skeleton which we cannot clearly define, and of which we may desire to know more. this can be done only by the use of far higher powers. to effect this, we must carefully cut off this delicate structure, and so prepare it that we may employ upon it the first of a series of our highest powers. the result of that examination is given here.[ ] you see that the whole organ has a distinct form and border, and that its carefully carved surface gives origin to wheel-like areolæ which form the bases of delicate hairs. the function of this organ is really unknown. it is known from its position as the _pygidium_; and from the extreme sensitiveness of the hairs to the slightest aerial movement, may be a tactile organ warning of the approach of enemies; the eyes have no power to see. but we have not reached the ultimate accessible structure of this organ. if we place a portion of the surface under one of the finest of our most powerful lenses, this will be the result.[ ] now, without discussing the real optical or anatomical value of this result as it stands, what i desire to remind you of is: . the natural size of the flea. . the increase of knowledge gained by its general enlargement. . the relation in size between the flea and its pygidium. . the manner in which our lenses reveal its structure, not merely amplify its form. [footnote : the pygidium of the flea, very highly magnified, was here shown.] [footnote : an illustration of the pygidium structure seen with one-thirty-fifth immersion was given.] now with these simple and yet needful preliminaries you will be able to follow me in a careful study of the least, the very lowliest and smallest, of all living things. it lies on the very verge of our present powers of optical aid, and what we know concerning it will convince you that we are prepared with competent skill to attack the problem of the life-histories of the smallest living forms. the group to which the subject of our present study belongs is the bacteria. they are primarily staff-like organisms of extreme minuteness, but may be straight, or bent, or curved, or spiral, or twisted rods. this entire projection is drawn on glass, with _camera lucida_, each object being magnified , diameters, that is to say, , , of times in area. yet the entire drawing is made upon an area of not quite inches in diameter, and afterward projected here. the objects therefore are all equally magnified, and their relative sizes may be seen. the giant of the series is known as _spirillum volutans;_ and you will see that the representative species given become less and less in size until we reach the smallest of all the definite forms, and known to science as _bacterium termo_. now within given limits this organism varies in size, but if a fair average be taken its size is such that , , laid in order would only fill the hundredth of a cubic inch. now the majority of these forms _move_ with rapidity and grace in the fluids they inhabit. but how? by what means? by looking at the largest form of this group, you will see that it is provided with two delicate fibers, one at each end. ehrenberg and others strongly suspected their existence, and we were enabled, with more perfect lenses, to _demonstrate_ their presence some twelve years ago. they are actually the swimming organs of this spirillum. the fluid is lashed rhythmically by these fibers, and a spiral movement of the utmost grace results. then do the intermediate forms that move also possess these flagella, and does this least form in nature, viz., _bacterium termo_, accomplish its bounding and rebounding movements in the same way? yes! by a series of resolute efforts, in using a new battery of lenses--the finest that at that time had ever been put into the hands of man--i was enabled to show in succession that each motile form of bacterium up to _b. lineola_ accomplished its movements by fibers or flagella; and that in the act of self-division, constantly taking place, a new fiber was drawn out for each half before separation. but the point of difficulty was _b. termo_. the demonstration of its flagella was a task of difficulty which only patient purpose could conquer. but by the use of our new lenses, and special illumination we--my colleague and i--were enabled to demonstrate clearly a flagellum at each end of this least of living organisms, as you see, and by the rapid lashing of the fluid, alternately or together, with these flagella, the powerful, rapid, and graceful movements of this smallest known living thing are accomplished. of course these fibers are inconceivably fine--indeed for this very reason it was desirable, if possible, to _measure_ it, to discover its actual thickness. we all know that, both for the telescope and the microscope, beautiful apparatus are made for measuring minute magnified details. but unfortunately no instrument manufactured was delicate enough to measure _directly_ this fiber. if it were measured it must be by an indirect progress, which i accomplished thus: the diameter of the body of _b. termo_, _i.e._, from; side to side, may in different forms vary from the / to the / of an inch. _that_ is a measurement which we may easily make directly with a micrometer. haying ascertained this, i determined to discover the ratio of thickness between the body of the bacterium and its flagellum--that is to say, to discover how many of the flagella laid side by side would make up the width of the body. i proceeded thus: this is a complicated microscope placed on a tripod, so arranged that it may be conveniently worked upright. there is a special instrument for centering and illuminating. on the stage of the instrument, the bacterium with its flagellum in distinct focus is placed. instead of the simple eyepiece, _camera lucida_ is placed upon it. this instrument is so constructed that it appears to throw the image of the object upon the white sheet of paper on the small table at the right hand where the drawing is made, at the, same time that it enables the same eye to see the pencil and the right hand. in this way i made a careful drawing of _b. termo_ and its flagellum, magnified , diameters. here is a projection of the drawing made. but i subsequently avoided paper, and used under the camera most carefully prepared surface of ground glass. when the drawing was made i placed on the drawing a drop of canada balsam, and covered it with a circle of thin glass, just like any other microscopic mounted object. this is a micro-slide so prepared. now you can see that i only have to lay this on the stage of a microscope, make it an object for a low power, and use a screw micrometer to find how many flagella go to the making of a body. the result is given in the figure; you see that ten flagella would fill the area occupied by the diameter of the body. in the case chosen the body was the / , of an inch wide, and therefore, when divided by ten, gave for the flagellum a thickness of the / , of an english inch. in the end i made fifty separate drawings with four separate lenses. i averaged the result in each fifty, and then took the average of the total of , and the mean value of the width of the flagellum was the / , of an english inch. it will be seen, then, that we are possessed of instruments which, when competently used, will enable us to study the life-histories of the putrefactive organisms, although they are the minutest forms of life. i have stated that they were the inevitable accompaniments of putrescence and decay. you learned from a previous illustration the general appearance of the bacteria; they are the earliest to appear whenever putrefaction shows itself. in fact the pioneer is this--the ubiquitous _bacterium termo._ the order of succession of the other forms is by no means certain. but whenever a high stage of decomposition is reached, a group of forms represented by these three will swarm the fluid. these are the monads, they are strictly putrefactive organisms, they are midway in size between the least and largest bacteria, and are, from their form and other conditions, more amenable to research, and twelve years ago i resolved, with the highest power lenses and considerable practice in their use, to attack the problem of their origin; whether as physical products of the not-living, or as the natural progeny of parents. but you will remember that only a minute drop of fluid containing them can be examined at one time. this minute drop has to be covered with a minute film of glass not more than the / of an inch thick. the highest lenses are employed, working so near as almost to touch the delicate cover. clearly, then, the film of fluid would rapidly evaporate and cause the destruction of the object studied. to prevent this an arrangement was devised by which the lens and the covered fluid under examination were used in an air-tight chamber, the air of which was kept in a saturated condition; so that being, like a saturated sponge, unable to take in any more, it left the film of fluid unaffected. but to make the work efficient i soon found that there must be a second observer. observation by leaps was of no avail. to be accurate it must be unbroken. there must be no gap in a chain of demonstration. a thousand mishaps would occur in trying to follow a single organism through all the changes of successive hours to the end. but, however many failures, it was evident, we must begin on another form at the earliest point again, and follow it to the close. i saw soon that every other method would have been merely empirical, a mere piecemeal of imagination and fact. when one observer's ability to continue a long observation was exhausted, there must be another at hand to take up the thread and continue it; and thus to the end. i was fortunate indeed at this time in securing the ready and enthusiastic aid of dr. j.j. drysdale, of liverpool, who practically lived with me for the purpose, and went side by side with me to the work. we admitted nothing which we had not both seen, and we succeeded each other consecutively, whenever needful, in following to the end the complete life-histories of six of these remarkable forms. i will now give you the facts in relation to two which shall be typical. we obtained them in enormous abundance in a maceration of fish. i will not take them in the order of our researches, but shall find it best to examine the largest and the smallest. the appearance of the former is now before you. it is divergent from the common type when seen in its perfect condition, avoiding the oval form, but it resumes it in metamorphosis. it is comparatively huge in its proportions, its average extreme length being the / of an inch. its normal form is rigidly adhered to as that of a rotifer or a crustacean. its body-substance is a structureless sarcode. its differentiations are a nucleus-like body, not common to the monads; generally a pair of dilating vacuoles, which open and close, like the human eyelid, ten to twenty times in every minute; and lastly, the usual number of four flagella. that the power of motion in these forms and in the bacteria is dependent upon these flagella i believe there can be no reasonable doubt. in the monads, the versatility, rapidity, and power of movement are always correlated with the number of these. the one before us could sweep across the field with majestic slowness, or dart with lightning swiftness and a swallow's grace. it could gyrate in a spiral, or spin on its axis in a rectilinear path like a rifled bullet. it could dart up or down, and begin, arrest, or change its motion with a grace and power which at once astonish and entrance. fixing on one of these monads then, we followed it doggedly by a never-ceasing movement of a "mechanical stage," never for an instant losing it through all its wanderings and gyrations; we found that in the course of minutes, or of hours, the sharpness of its outline slowly vanish, its vacuoles disappeared, and it lost its sharp caudal extremity, and was sluggishly amoeboid. this condition tensified, the amoeboid action quickened as here depicted, the agility of motion ceased, the nucleus body became strongly developed, and the whole sarcode was in a state of vivid and glittering action. if now it be sharply and specially looked for, it will be seen that the root of the flagella _splits_, dividing henceforth into two separate pairs. at the same moment a motion is set up which pulls the divided pairs asunder, making the interval of sarcode to grow constantly greater between them. during this time the nuclear body has commenced and continued a process of self-division; from this moment the organism grows rapidly rounder, the flagella swiftly diverge. a bean-like form is taken; the nucleus divides, and a constriction is suddenly developed; this deepens; the opposite position of the flagella ensues, the nearly divided forms now vigorously pull in opposite directions, the constriction is thus deepened and the tail formed. the fiber of sarcode, to which the constricted part has by tension been reduced, now snaps, and two organisms go free. it will have struck you that the new organism enters upon its career with only _two_ flagella, and the normal organism is possessed of four. but in a few minutes, three or four at most, the full complement were always there. how they were acquired it was the work of months to discover, but at last the mystery was solved. the newly-fissioned form darted irregularly and rapidly for a brief space, then fixed itself to the floor or to a rigid object by the ends of its flagella, and, with its body motionless, an intense vibratory action was set up along the entire length of these exquisite fibers. rapidly the ends split, one-half being in each fiber set free, and the other remaining fixed, and in seconds each entire flagellum was divided into a perfect pair. now the amoeboid state is a notable phenomenon throughout the monads as precursive of striking change. it appears to subserve the purpose of the more facile acquisition and digestion of food at a crisis. and this augmented the difficulty of discovering further change; and only persistent effort enabled us to discover that with comparative rareness there appeared a form in an amoeboid state that was unique. it was a condition chiefly confined to the caudal end, the sarcode having became diffluent, hyaline, and intensely rapid in the protrusion and retraction of its substance, while the nuclear body becomes enormously enlarged. these never appear alone; forms in a like condition are diffused throughout the fluid, and may swim in this state for hours. meanwhile, the diffluence causes a spreading and flattening of the sarcode and swimming gives place to creeping, while the flagella violently lash. in this condition two forms meet by apparent accident, the protrusions touch, and instant fusion supervenes. in the course of a few seconds there is no disconnected sarcode visible, and in five to seven minutes the organism is a union of two of the organisms, the swimming being again resumed, the flagella acting in apparent concert. this may continue for a short time, when movement begins to flag and then ceases. meanwhile, the bodies close together, and the eyenots or vacuoles melt together, the two nuclei become one and disappear, and in eighteen hours the entire body of "either has melted into other," and a motionless, and for a time irregular, sac is left. this now becomes smooth, spherical, and tight, being fixed and motionless. this is a typical process; but the mingled weariness and pleasure realized in following such a form without a break through all the varied changes into this condition is not easily expressed. but now the utmost power of lenses, the most delicate adjustment of light, and the keenest powers of eyesight and attention must do the rest. before the end of six hours the delicate glossy sac opens gently at one place, then there streams out a glairy fluid densely packed with semi-opaque granules, just fairly visible when their area was increased six millions of times, and this continued until the whole sac was empty and its entire contents diffused. to follow with our utmost powers these exquisite specks was an unspeakable pleasure, a group seen to roll from the sac, when nearly empty, were fixed and never left. they soon palpably changed by apparent swelling or growth, but were perfectly inactive; but at the end of three hours a beaked appearance was presented. rapid growth set in, and at the end of another hour, how has entirely baffled us, they acquired flagella and swam freely; in thirty-five minutes more they possessed a nucleus and rapidly developed, until at the end of nine hours after emission a sporule was followed to the parent condition and left in the act of fission. in this way, with what difficulties i need not weary you, a complete life-cycle was made out. and now i will invite your attention to the developmental history of the _most minute_ of the six forms we studied. in form it is a long oval, it is without visible structure or differentiation within, and is possessed of only a single flagellum. its utmost length is the / of an inch. its motion is continuous in a straight line, and not intensely rapid, nor greatly varied, being wholly wanting in curves and dartings. the copiousness of its increase was, even to our accustomed eyes, remarkable in the extreme, but the reason was discovered with comparative ease. its fission was not a division into two, but into many. the first indication of its approach in following this delicate form was the assumption rapidly of a rounder shape. then followed an amoeboid and uncertain form, with an increased intensity of action which lasted a few moments, when lassitude supervened, then perfect stillness of the body, which is now globular in form, while the flagellum feebly lashed, and then fell upon and fused with the substance of the sarcode. and the result is a solid, flattened, homogeneous ball of living jelly. to properly study this in its further changes, a power of from three to four thousand diameters must be used, and with this i know of few things in the whole range of minute beauty more beautiful than the effect of what is seen. in the perfectly motionless flattened sphere, without the shimmer of premonition and with inconceivable suddenness, a white cross smites itself, as it were, through the sarcode. then another with equal suddenness at right angles, and while with admiration and amazement one for the first time is realizing the shining radii, an invisible energy seizes the tiny speck, and fixing its center, twists its entire circumference, and endows it with a turbined aspect. from that moment intense interior activity became manifest. now the sarcode was, as it were, kneading its own substance, and again an inner whirling motion was visible, reminding one of the rush of water round the interior of a hollow sphere on its way to a jet or fountain. deep fissures or indentations showed themselves all over the sphere; and then at the end of ten or more minutes all interior action ceased, and the sphere had segmented into a coiled mass. there was no trace of an investing membrane; the constituent parts were related to each other simply as the two separating parts of an ordinary fission; and they now commenced a quick, writhing motion like a knot of eels, and then, in the course of from seven to thirty minutes, separated, and fully endowed with flagella swam freely away, minute but perfect forms, which by the rapid absorption of pabulum attained speedily to the parent size. it is characteristic of this group of organic forms that multiplication by self-division is the common and continuous method of increase. the other and essential method was comparatively rare and always obscure. in this instance, on the first occasion the continuous observation of the same "field" for five days failed to disclose to us any other method of increase but this multiple-fission, and it was only the intense suggestiveness of past experience that kept us still alert and prevented us from inferring that it was the _only_ method. but eventually we perceived that while this was the prevailing phenomenon, there were scattered among the other forms of the same monad _larger_ than the rest, and with a singular granular aspect toward the flagellate end. it may be easily contrasted with the normal or ordinary form. now by doggedly following one of these through all its wanderings a wholly new phase in the morphology of the creature was revealed. this roughened or granular form seized upon and fastened itself to a form in the ordinary condition. the two swam freely together, both flagella being in action, but it was shortly palpable that the larger one was absorbing the lesser. the flagellum of the smaller one at length moved slower, then sluggishly, then fell upon the sarcode, which rapidly diminished, while the bigger form expanded and became vividly active until the two bodies had actually fused into one. after this its activity diminished, in a few minutes the body became quite still, leaving only a feeble motion in the flagellum, which soon fell upon the body-substance and was lost. all that was left now was a still spheroidal glossy speck, tinted with a brownish yellow. a peculiarity of this monad is the extreme uncertainty of the length of time which may elapse before even the most delicate change in this sac is visible. its absolute stillness may continue for ten or more hours. during this time it is absolutely inert, but at last the sac--for such it is--opens gently, and there is poured out a brownish glairy fluid. at first the stream is small, but at length its flow enlarges the rift in the cyst, and the cloudy volume of its contents rolls out, and the hyaline film that inclosed it is all that is left. the nature of the outflow was like that produced by the pouring of strong spirit into water. but no power that we could employ was capable of detecting a _granule_ in it. to our most delicate manipulation of light, our finest optical appliances, and our most riveted attention, it was a homogeneous fluid and nothing more. this for a while baffled and disturbed us. it lured us off the scent. we inferred that it might possibly be a fertilizing fluid, and that we must look in other directions for the issue. but this was fruitless, and we were driven again to the old point, and having once more obtained the emitted fluid, determined to fix a lens magnifying , diameters upon a clear space over which the fluid had rolled, and near to the exhausted sac, and ply our old trade of _watching_ with unbroken observation. the result was a reward indeed. at first the space was clear and white, but in the course of a hundred minutes there came suddenly into view the minutest conceivable specks. i can only compare the coming of these to the growth of the stars in a starless space upon the eye of an intense watcher in a summer twilight. you knew but a few minutes since a star was not visible there, and now there is no mistaking its pale beauty. it was so with these inexpressibly minute sporules; they were not there a short time since, but they grew large enough for our optical aids to reveal them, and there they were. such a field after one hour's watching i present to you. and here i would remark that these delicate specks were unlike any which we saw emerge directly from the sac as granules. in that condition they were always semi-opaque, but here they were transparent, and a brown yellow, the condition always sequent upon a certain measure of growth. to follow these without the loss of an instant's vision was pleasure of the highest kind. in an hour and ten minutes from their first discovery they had grown to oval points. in one hour more the specks had become beaked and long. and this pointed end was universally the end from which the flagellum emerged. with the flagellum comes motion, and with that abundant pabulum, and therefore rapid growth. but when motion is attained we are compelled to abandon the mass and follow one in all its impetuous travels in its little world; and by doing so we are enabled to follow the developed speck into the parent condition and size, and not to leave it until it had, like its predecessors, entered on and completed its wonderful self-division by fission. it becomes then clearly manifest that these organisms, lowly and little as they are, arise in fertilized parental products. there is no more caprice in their mode of origin than in that of a crustacean or a bird. their minuteness, enormous abundance, and universal distribution is the explanation of their rapid and practically ubiquitous appearance in a germinating and adult condition. the presence of putrefiable or putrescent matter determines at once the germination of the always-present spore. but a new question arises. these spores are definite products. in the face of some experimental facts one was tempted to inquire: have these spores any capacity to resist heat greater than the adults? it was not easy to determine this question. but we at length were enabled to isolate the germs of seven separate forms, and by means of delicate apparatus, and some twelve months of research, to place each spore sac in an apparatus so constructed that it could be raised to successive temperatures, and without any change of conditions examined on the stage of the microscope. in this way we reached successive temperatures higher and higher until the death point--the point beyond which no subsequent germination ever occurred--was reached in regard to _each_ organism. the result was striking. the normal death point for the adult was ° f. one of the monads emitted from its sac minute mobile specks--evidently living bodies--which rapidly grew. these we always destroyed at a temperature of ° f. three of the sacs emitted spores that germinated at every temperature under ° f. two more only had their power of germination destroyed at ° f. and one, the least of all the monad forms, in a heat partially fluid and partially dry, at all points up to ° f. but if wholly in fluid it was destroyed at the point of ° f. the average being that the power of heat resistance in the spore was to that of the adult as to . from this it is clear that we dare not infer spontaneous generation after heat until we know the life-history of the organism. in proof of this i close with a practical case. a trenchant and resolute advocate of the origin of living forms _de novo_ has published what he considers a crucial illustration in support of his case. he took a strong infusion of common cress, placed it in a flask, boiled it, and, while boiling, hermetically sealed it. he then heated it up in a digester to ° f. it was kept for nine weeks and then opened, and, in his own language, on microscopical examination of the earliest drop "there appeared more than a dozen very active monads." he has fortunately measured and roughly drawn these. a facsimile of his drawing is here. he says that they were possessed of a rapidly moving lash, and that there were other forms without tails, which he assumed were developmental stages of the form. this is nothing less than the monad whose life-history i gave you last. my drawings, magnified , diams., of the active organism and the developing sac are here. now this experimenter says that he took these monads and heated them to a temperature of about ° f., and they were all absolutely killed. this is accurately our experience. but he says these monads arose in a closed flask, the fluid of which had been heated up to ° f. therefore, since they are killed at ° f., and arose in a fluid after being heated to ° f., they must have arisen _de novo!_ but the truth is that this is the monad whose spore only loses its power to germinate at a temperature (in fluid) of °, that is to say, ° f. higher than the heat to which, in this experiment, they had been subjected. and therefore the facts compel the deduction that these monads in the cress arose, not by a change of dead matter into living, but that they germinated naturally from the parental spore which the heat employed had been incompetent to injure. then we conclude with a definite issue, viz., by experiment it is established that living forms do not now arise in dead matter. and by study of the forms themselves it is proved that, like all the more complex forms above them, they arise in parental products. the law is as ever, only that which is living can give origin to that which lives. * * * * * a catalogue, containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . , stitched in paper, or $ . , bound in stiff covers. combined rates--one 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[illustration] scientific american supplement no. new york, june , . scientific american supplement. vol. xlv., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. archÆology.--tombs of the first egyptian dynasty--by ludwig borchardt ii. anthropology.--the milestones of human progress iii. biography.--the queen regent and alfonzo xiii.-- illustration iv. botany and horticulture.--rose psyche-- illustration v. civil engineering.--the lock of the dortmund-ems canal at henrichenburg.-- illustration vi. electricity.--the development of the central station--by samuel insull vii. marine engineering.--steering gear of north german lloyd steamers "coblentz," "mainz" and "trier."-- illustrations viii. medicine and hygiene.--sleep and the theories of its cause ix. miscellaneous: engineering notes. electrical notes. selected formulæ. x. natural history--wild and domestic sheep in the berlin zoological garden.-- illustrations xi. patents.--patents.--by james w. see xii. photography.--amateur chronophotographic apparatus.-- illustrations xiii. steam engineering.--combined steam pumping and motive power engine.-- illustration xiv. technology.--the reclaiming of old rubber.--by hawthorne hill xv. warfare.--the american "regular."--by the english correspondent of the london times on board the united states transport "gussie." * * * * * the queen regent and alfonzo xiii. [illustration: the queen regent and her son, king alfonso xiii. of spain.] in the present war between the united states and spain, the queen regent is an impressive figure, and it is entirely owing to her charm and fortitude that the present dynasty of spain is maintained. since his earliest youth she has constantly made efforts to fit her son to wear the crown. the queen regent came from the great historic house of hapsburg, which has done much to shape the destinies of the world. all the fortitude that has distinguished its members is represented in this lady, who is the widow of alfonzo xii. and the mother of the present king. her father was the late archduke karl ferdinand and she is the cousin of emperor franz joseph. she has had a sad history. her husband died before the young king was born, and from the hour of his birth she has watched and cared for the boy. she is the leader in all good works in spain, and her sympathy for the distressed is proverbial. she gives freely from her private purse wherever there is need, whether it be for the relief of misery or, as recently, when the state is in peril. the young king has been carefully educated. by a curious fate, his birth deposed from the throne his sister maria de las mercedes, who as a little girl was queen for a few months. the boy has been brought up under the influence of family life and has a warm affection for his mother and sisters. he has never had the full delights of childhood, for he has been educated in that false, punctilious and thoroughly artificial atmosphere of the court of spain, in which every care has been taken to fit him for his royal position. his health is far from robust, though the military education he has received has done much to strengthen his constitution. he has been taught to interest himself especially in the naval and military affairs, and the study of the models of ships and military discipline has been one of the principal occupations of his childhood. it is the earnest wish of spain that he should prove worthy of his mother. * * * * * the milestones of human progress.[ ] [footnote : a lecture delivered by prof. daniel g. brinton at the academy of natural sciences, philadelphia.] the subject pertains directly to the advancement of the race. indeed, it is to the measure of this advancement i shall ask your attention. there is no doubt about the advancement. there are some people who believed and believe that man began in a state of high development and has since then degenerated into his present condition. the belief in some period of arcadian simplicity and human perfection is still to be found in some remote nooks and crannies of the learned world; but those minds who have been trained in archæological studies and in ethnographic observations know well that when we go back to the most ancient deposits, in which we find any sign of man at all on the globe, we find also the proofs that man then lived in the rudest possible condition of savagery. he has, little by little, through long centuries and millenniums of painful struggle, survived in made his weapons and his most effective tools for the time being would be a good criterion to go by, because these weapons and tools enabled him to conquer not only the wild beasts around him and his fellow man also, but nature as well. these materials are three in number. they particularly apply to european archæology, but, in a general way, to the archæology of all continents. the one is stone, which gave man material for the best cutting edge which he could make for very many millenniums of his existence. after that, for a comparatively short period, he availed himself of bronze--of the mixture of copper and tin called bronze--an admixture giving a considerable degree of hardness and therefore allowing polish and edge making. the bronze age was not long anywhere. it was succeeded by that metal which, beyond all others, has been of signal utility to man--iron. we live in the iron age, and it is from iron in some of its forms and products that all our best weapons and materials for implements, etc., are derived. we have, therefore, the ages of stone, of bronze and of iron. these are the measures, from an artistic source, of the advancement of human culture; and they certainly bear a distinct relation to all man's other conditions at the time. a tribe which had never progressed beyond the stone age--which had no better material for its weapons and implements than stone--could never proceed beyond a very limited point of civilization. bronze or any metal which can be moulded, hammered and sharpened of course gives a nation vast superiority over one which uses stone only; and the value of iron and steel for the same purposes i need not dwell upon. to be sure, we have here several measures; and it would seem more desirable, if we could, to obtain one single measure--one single material or object of which we could say that the tribe that uses or does not use that to an equal degree is certainly lower or, in the other respects, higher than another; but i believe that there has been no single material which has been suggested as of sufficient use and value in this direction to serve as a criterion; but, yes! i remember there was one and, on the whole, not a bad one. it was suggested by baron liebig, the celebrated chemist, who said: "if you wish a single material by which to judge of the amount of culture that any nation, or, for that matter, any individual, possesses, compared to another one, find out how much soap they use. nothing," he said, "more than personal cleanliness and general cleanliness differentiates the cultured man from the savage;" and as for that purpose he probably had in view a soap, he recognized that as the one criterion. it is not amiss, but open, also, to serious objections; because there are tribes who live in such conditions that they can get neither water nor soap; and the arabs, distinctly clean, are not by any means at the highest pinnacle of civilization. the germans, therefore, as a rule, have sought some other means than all those above mentioned. almost all the german writers on ethnography divide the people and nations of the world into two great classes--the one they call the "wild peoples," the other the "cultured peoples"--the "natur-voelker" and the "kultur-voelker." the distinction which they draw between these two great classes is largely psychological. man, they say, in the condition of the "wild people"--of the "natur-voelker"--is subject to nature; therefore, they call them "nature people." the "kultur-voelker," on the other hand, have emancipated themselves, in great measure, from the control of nature. furthermore, the man in the condition of the "wild people" is in a condition of practically unconscious life: he has not yet arrived at self-consciousness--he does not know and recognize his individuality--the "ego"--"das ich;" that is a discovery which comes with the "kultur-voelker"--with the "cultured people;" and just in proportion as an individual (or a nation) achieves a completely clear idea of his own self-existence, his self-consciousness, his individuality, to that extent he is emancipated from the mere control of nature around him and rises in the scale of culture. again, to make this difference between the two still more apparent, it is the conflict between the instinctive desires and the human heart and soul and the intelligent desires--those desires which we have by instinct, which we have by heredity and which have been inculcated into us wholly by our surroundings, which we drink in and accept without any internal discussion of them: those are instinctive in character. we go about our business, we transact the daily affairs of life, we accept our religion and politics, not from any internal conviction of our own or positive examination, but from our surroundings. to that extent people are acting instinctively; and, as such, they are on a lower stage of culture than those who arrive at such results for themselves through intelligent personal effort. this is a real distinction also, although somewhat more subtle, perhaps, than the ones previously given. therefore, the differentiation made by the german ethnographers between wild people and the cultured peoples is, in the main, right; but it does not admit of any sharp line of distinction between the two. we cannot draw a fixed line and say, "on this side are the cultured people and on that the wild," because there are many tribes and nations who are about that line, in some respects on one side of it, in others on the other; but in a broad, general way this distinction (which is now universally adopted by the german writers) is one we should keep in our minds as being based upon careful studies and real distinctions. usually the writers in the english tongue prefer a different basis than any of these which i have mentioned; they prefer the basis as to whence is derived the food supply of a nation, or a tribe; and on the source of that food supply they divide nations and tribes into the more or less cultured. in earliest times (and among the rudest tribes to-day) the food supply is furnished entirely by natural means; there is little or no agriculture known to speak of; there is nothing in the way of preserving domestic animals for food; hunting the wild beasts of the forests and fishing in the streams are the two sources. therefore, we call that last condition the hunting and fishing stage of human development. you will observe that when that prevails there can be no congregation of men into large bodies. such a thing as a city would be unknown. the food supply is eminently precarious. it depends upon the season and upon a thousand matters not under the control of man in any way. moreover, inasmuch as the supply at the best is uncertain, it allows but a very limited population in a district; nor does it permit any permanent or stable inhabitations. the towns, such as they are, must be movable; they must go to one part of the country in the summer and another in the winter; they must follow the game and the fruits; and in that condition, therefore, of unstable life it is not possible for a nation or a tribe to gain any great advance. you observe, therefore, that when the food supply is drawn from this source it does entail a general depravity of culture everywhere. above that would come the food supply which is obtained from other sources. there is one which is not universal but still widely extended, and that is the pastoral life. there are many tribes (as, for instance, in southern africa and in india and throughout the steppes of tartary and elsewhere) who live on their herds and drive their herds from one pasture to another in order to obtain the best forage. this nomadic and pastoral life extended very widely over the old world in ancient times, but existed nowhere in the new world, for the simple reason that they had no domesticated animals. our own remote ancestors--both the aryans and the semites--all the early ancestors of the white race so far as known, were pastoral or nomadic; and the aryans of central europe remained so until after the fall of rome, when, for the first time, they became practically sedentary. this nomadic and pastoral life is a very great advance over the mere hunting and fishing stage. it requires considerable care and attention to domesticate the wild animals in any sufficient quantity to form a reliable source of food. moreover, the attention which it was necessary to give to the rearing and training and the looking after domestic animals was to a certain extent, humanizing. when a man found that it was necessary to be careful about his animals, he would also be careful about his neighbors. we would say that the same sense which enabled him, or directed him, to look after the welfare of the herd would justify and, in fact, impel him to look after that of man also; so that the nomadic and pastoral life, although not stable nor favorable to the development of cities, nor the great extension of commerce, was nevertheless a decided advance over the ruder hunting and fishing stage. so far as we know, neither aryan nor semite ever depended upon a hunting and fishing stage. they doubtless did, but not in the time of any history that we know. the bedouins, etc., wandering tribes to-day, and, among the semitic, the tuaregs of the sahara, are a purely nomadic or pastoral race; yet are very much above the negroes of the south, who depend upon hunting and fishing. above it, however, and a very great improvement upon it, is the agricultural stage, where the main source of the food supply is the harvests. you observe, at once, that that means a sedentary life. when a man sows corn, he must wait thereabout and tend it and till it and finally reap it and store it and thrash it and then preserve the grain and build granaries for it; and it involves, in fact, the remaining in one place all the whole year; and then the regularity of that life led very distinctly to making men regular, generally, in their habits. they wanted to defend their homes--defend these grain fields of theirs, or starvation would result; therefore, they built towers and strong-walled cities; and they took great care in the selection of the best men among them to do the fighting, while others looked after the crop. we find that agriculture began at a very, very early period in both continents. in our own continent we cannot tell when agriculture was first in use--the main crop being the maize, or indian corn. it was raised by the more advanced tribes from the extreme north, where its profitable culture invited, to the extreme south, from about the northern line of wisconsin in north america to the latitude of southern chile in south--extending, therefore, over some seven to eight thousand miles of linear distance. in the old world (going back to the time of the lake dwellers) we know they had barley, rye and a species of millet; and later on they were introduced to oats and wheat and a variety of others. rice was of the very earliest of our cereals, in the extreme east of the old world. wherever we find a very ancient civilization we also find that it is intimately connected with some important cereal, and it has been said that all you have to do is to study botany--the history of botany--and you will find the history of human culture; and much there is that could be said for that. fourth, and finally, those who divide human culture according to the food supply consider that the highest stage is reached through commerce. commerce brings to all the great centers of human life the food essential to their sustenance. it would be absolutely impossible--obviously so--to have a city like philadelphia in existence for a month without constant and ceaseless commerce brought here the food for its inhabitants. it is quite likely that, were philadelphia shut off at once from all connection with the world, within ten days there would be an absolute famine here--so closely do we depend upon our commercial supplies for our subsistence. these supplies are not drawn from any one locality; were we to draw a radius of five hundred miles around our great city of a million inhabitants, we should still find that the greater part of our food supply comes from a wider distance from us than that; and there is no one of us that will go to his table this evening but will see upon that table food products drawn from every quarter of the world. thus it is that commerce enables man to reach an indefinite degree of consolidation; and it is through consolidation--through the more and more intimate relationship, and the closer and closer juxtaposition of man--that his real benefit and progress may be derived. these, therefore, are the four stages of culture, as depending upon food supply: the hunting and fishing stage, the nomadic or pastoral, the agricultural and the commercial. these have been generally adopted by english writers, and they are so adopted to-day; and you will probably find them in many of the text books. the american writers have, in many instances, followed the principles laid down and defined most clearly by mr. lewis h. morgan, a distinguished ethnologist of the last generation. he divides (or accepted the division and largely defined it) the progress of man into a series of stages: beginning at the lowest point with savagery; then barbarism, semi-civilization, civilization, and fifth, enlightenment. i may briefly refer to what he would include in these and the main criteria which he gives for each of them. he would place the savage condition as being that of the lowest tribes known to us. they have little or no agriculture; their commerce is very inchoate and rude: they have no knowledge of the metals as such; their best weapon is the bow and arrow, or the throwing stick; and their best tool is the stone hatchet and the stone spade. this is very much like the lowest condition of the "wild people" to whom i referred. above that he would place the condition of barbarism. in the stage of developed barbarism he would place such inventions as, for instance, pottery, the art of weaving (which is a very primitive art) and the taming of a certain number of domestic animals, some for food, some for amusement and hunting, and also the beginnings of the development of agriculture. a type of such a nation of barbarism would be the indians who used to live here--the algonkian--the delaware indians. when the first europeans came to the shores of the delaware river they did not find absolutely rude savages. the delaware indians had moderately stationary villages surrounded by pickets, the houses being built of strong timber; they had large fields of maize, pumpkins, squashes and beans, which they cultivated diligently during the summer and stored the food for their winter's supply. they depended largely, to be sure, upon hunting and fishing also; but along with that they had these simple arts: from the rushes which grew below philadelphia, in a place called the "neck," they used to weave mats for protecting the floors and also for building the sides of their summer houses and for sleeping upon. they had a method of tanning and dressing buckskin and using it for the purposes of clothing. they were by no means naked savages; they were clothed, and tolerably well clothed; they could make pottery, and the pottery was decorated sometimes with interesting designs, of which we have specimens in our cabinets. therefore, we find among the old delaware indians who formerly lived on the site of philadelphia a fair specimen of a nation in a barbarous stage, decidedly superior to the australian natives of to-day or the indians of the terra del fuego or the northern part of british america, who are in the state of complete savagery. above that is the period of semi-civilization, a stage marked by the discovery of the method of building stone walls. no algonkian or iroquois indian ever built a stone wall in his life; there is no record of any and no signs of any throughout the united states east of the mississippi; there was never a stone wall built by a native tribe that really amounted to anything more than a stone pile; but we do find that in the southwest, among the cliff dwellers, and in various parts of central america and south america, the stone wall was not only known, but it was constructed with a great deal of durability and skill. also, some knowledge of metals was found among most of the semi-civilized people. the mexicans and the peruvians were in a state of semi-civilization when they were discovered by the whites the first time. they, built many extensive temples and houses, erected frequently upon pyramids, the pyramids themselves being supported by stone walls. they knew the dressing of stone; they were distinctly agricultural and depended more on that than anything else for their food supply. they had developed a system of mnemonic records which, in the yucatan culture, might be called picture writing, but was not phonetic writing in our true sense of the term. the also knew something about weighing and measuring. they had definite laws, laws which were carried out by properly appointed individuals. their towns and cities would often number thousands of inhabitants; they had roads connecting them, which roads were kept in good condition; they had a regular army made up of men selected and trained for that purpose. in all these respects we see nations who were semi-civilized, but they were not yet civilized. we could call a nation civilized that had a distinct system of phonetic writing and used it; but not all nations having this are civilized. it is only when it is used freely and for purposes of business that we can call them civilized. the wild tuaregs of the sahara have a system of phonetic writing used by a few of them--the women being the literati of those tribes (the men not knowing how to read or write); but civilization means more than this; it means the use of iron weapons and tools; it means also the adoption of a definite currency which is established on a fixed basis and recognized throughout the community; it means the establishment of commercial lines--a progress distinct above that which is the mere barter of the lower conditions of savagery and barbarism. in all these respects we see that civilization means a type about such as we enjoy at present. it is such as has existed in europe since the renaissance; because during the middle ages we could only say that europe was in a semi-civilized condition. they knew something about writing; but at a time when dean, the writer of the early history of england, said that throughout the whole of england there were not half a dozen men who could read what he had written, you can see that writing was a very unimportant part of the culture of that nation; so it can only be when writing becomes a common possession of the majority that we can call it an element of civilization. it is not to be supposed that we ourselves have reached the type of the highest culture. we leave something for our descendants to do. we do not wish to relieve them of the privilege of being better than ourselves; and we shall leave them, probably, plenty of room; because it is supposed that the stage of enlightenment which is the highest stage of culture--which we foresee, but do not see--that that rather applies to the future than to ourselves. that period will come when mankind has freed itself very much more than now from the bonds of nature and the environment of society. it will come when the ideas of our equality are much more perfect than they are now; when that equality extends to the equality of women with men before the law and in all rights; when it comes to the equality of all men of all castes before the law and the equal opportunity of all men to obtain that which is best in the life of all. we are very far from that yet. it will come also when the idea of international legislation is such that it will not be necessary, in order to cure great evils, that we should have recourse to weapons of any material whatsoever; that time is not yet come; and so we have much that is left for our descendants to work out in this direction. it would, however, appear that all these various criteria which i have named are somewhat unsatisfactory. they do not, it appears to me, quite touch the question at issue. they are in a measure external measures altogether--even that somewhat psychological one which i quoted from the german authorities. were i to propose a criterion, or a series of criteria, of culture which could be applied to all nations, it would be that which might as well and easily be applied to each individual; and when we come to apply it in that manner it is much more easy to understand its bearing. herbert spencer, in defining what he means by culture, says: "it means the knowledge of one thing thoroughly and a knowledge of the groundwork of all other branches of human knowledge." he claimed that we can only understand one thing thoroughly; but that we could and ought to understand the general outline of all other things which are studied by mankind. this is somewhat defective, it appears, because it bases culture entirely from an intellectual point of view; and if man were merely a walking intellectual machine, it would be well enough; but he is not; for the intellectual man is but a small portion of his life. we are engaged, most of our time, in something which is very far from purely intellectual action. we are governed distinctly by our emotions and our feelings--our sentiments; and culture must touch them, or it is vague and empty. therefore it is that i would say that we should think with goethe--to whom we must often recur for an insight into the profoundest trends of human nature--must recur to him; and we find that he lays down the principle of culture in the individual to be "a general sympathy with all the highest ideas which have governed and are governing the human mind." he said: "we should keep ourselves first (each man and woman should keep himself and herself) in touch with the highest elements of his and her own nature." he said, "it is not so difficult, if we give but a little time to it--provided we give that time regularly. we must remember," he says, "to cultivate our intellect by some study, every day and our sense of the beautiful by looking at something which is beautiful; and there is much around us which costs us nothing to look at were we to observe it--the cloud, the sunlight, the tree, the flower, a butterfly--anything of that kind studied for a few minutes each day would continue to develop in man's mind the sense of the beautiful. we should also appreciate carefully our actions and govern them and measure them, as to whether they are just to others--a matter which a very few minutes a day will probably enable us to do;" and so also he would go further and seek to find, in the idea of truth itself, as to what we ought and ought not to believe--trying to discover some one test of truth which we can apply. indeed, we may therefore formulate and apply to nations at large what goethe has there suggested; and we shall find it can be arranged in what i may call a pentatonic scale of culture. you may be aware that all musical scales of all savage and barbarous and primitive tribes are not in the octave, as ours, but in five notes only; they all have one musical scale only, and that is a pentatonic scale; and it is perhaps because they feel that their own minds are based upon some such arrangement as that (although that is an idea which i do not subscribe to, but only suggest); but when we come to look over the whole cycle of culture, as we find it described in the histories of culture--in the histories of civilization--we find that they are all efforts to develop one or the other, or several, of five primary ideas which are in the mind of every human being; and when they are developed, then culture is perfect, either in the individual or in the nation or the race. these five primitive ideas, innate in every human soul, are the ideas of the useful, of the beautiful, of the just, of the good and of the true, and you will not find any savage (provided he is not deficient in the ordinary mental ability of his tribe) who does not indicate an appreciation of every one of these in his own way. it is the idea of the useful which teaches him his utilitarian arts; which teaches him to build his house; to chip the flint for his weapon; to sharpen the stick to dig the place to drop the seed; and all those we call the arts of utility, the useful arts; and yet you will not find a savage tribe to-day but what goes somewhat above this; because among them all they make also an effort that these tools and weapons of theirs shall have some sign about them of the beautiful; and you will find decoration--indeed, "the painted savage" is a name we give to the lowest order of humanity; yet this same paint is to make himself beautiful; and so it is throughout all his games and amusements in life--you will find he is constantly striving at the idea of decoration--at the idea of beauty; little by little he develops this, until it becomes, in some nations, the joy of their existence and the lesson of the race, as in the ancient greeks; as in the italians of the time of the renaissance. these are what we call the æsthetic emotions, based upon an innate sense and love of the beautiful: and we may also turn to the lowest savage--we shall not find him deficient in justice; on the contrary, among the rudest australians, without shelter or clothing, you will find that the law of the tribe is well defined and also implacable; and a man who has sinned knows that he must meet it or flee; he knows that there is no avail or recourse beyond the tribal council, and he knows what they will decide in his particular case, because he knows the law and the penalty of its infringement. and this rude notion of justice develops, little by little, into the great edifice of jurisprudence, the law of nation and the law of nations. thus we find that the idea of the just, and of what is right from man to man, is something which is found everywhere; and as that develops culture develops; but the mere just alone does not satisfy the human heart; the man who merely metes out to his fellow that which the tribal law, or the law of the land, requires of him, certainly is not up to the ideal of any man or woman in this assembly or in this city. there is something beyond that, and what is that? we find that it rests in the idea of the good--that which is often brought forward in the beautiful forms of religion, which tells man that above justice there is something greater and nobler than mere ethics or morality--the mere right and wrong--the mere giving what is due. it is not enough to do that; there must be a giving of more than is due; because the idea of the good transcends the present life--it passes into the future life of the species; and it is only through going above what is needed to-day that we may endow our posterity with something greater than we ourselves possess. it is the idea of the good, therefore, which lifts that which is merely just into a higher--into, i might say, an immortal sphere of activity. it has always had an intense attraction for noble souls, which history shows us; and it is not to be supposed that that attraction will ever diminish; it will ever increase, although its forms may change; and finally, along with this betterment of the emotions, and of the sense of justice--of right and of ethics and of æsthetics--we find the constant effort and desire of all mankind, in all stages of culture, to find out what is true, as distinct from that which is not true. you will not be mistaken if you seek for this in the soul of the rudest savage; he, too, likes to know the truth. the methods by which he arrives at it, or seeks to arrive at it, are widely different from those which you have been taught. nevertheless, the logical force of his mind; the methods of thought that he has; the laws that govern his intelligence, are exactly the same as yours: and it is only with your enlightenment you have gained more and more acquaintance with the methods. you know something about the great discovery which has advanced all modern science from its mediæval condition to that of the present--of the application of the inductive system of science and thought; and you know that it is by constant and close mathematical study of analogy--of probability--that we exclude error little by little from our observations--we improve more and more our instruments of precision--we count out the errors of our observation; and we are constantly seeking those laws which are not transient and ephemeral only, but which are eternal and immortal. upon those laws, finally, must rest all our real, certain knowledge; and it is the endeavor of the anthropologist to apply those laws to man and his development; and such, indeed, is the recognized and highest mission of that science. we thus find that the idea of truth is at the summit of this scale which i have placed before you--not separated from it. it interprets every one of the ideas and justifies them and qualifies them and lifts them up into their highest usefulness. chevalier bunsen, in describing what he thought would be the highest condition of human enlightenment, said, "it will be when the good will be the true and the true will be the good;" and he might have extended that further and said, when both those ideas were the inspiring motives of all these five great ideas which i have stated are at the basis of the culture of every individual and are also at the basis of the culture of the race and of the nation. this, therefore, will serve as a sketch of the milestones of human progress. the way has been long and painful; the results have been far from satisfactory; and yet they have been enormous and wonderful, when we compare them now with what our ancestors were when history began. we can conclude, however, from looking back on this thorny and upward path, that it is still going to ascend; we do not know it for certain; progress may cease, through some unknown law, now and here; but if there is anything that we can derive from the lesson of the past--if we can project into the future any of the facts which history shows us are our own now--it guides us forward to a firm belief that the hereafter will have in its breast greater treasures for humanity, greater glories for posterity, than any that we know or can understand. * * * * * tombs of the first egyptian dynasty.[ ] [footnote : the independent.] by ludwig borchardt, ph.d., director of the german school in cairo. for many years various european collections of egyptian antiquities have contained a certain series of objects which gave archæologists great difficulty. there were vases of a peculiar form and color, greenish plates of slate, many of them in curious animal forms, and other similar things. it was known, positively, that these objects had been found in egypt, but it was impossible to assign them a place in the known periods of egyptian art. the puzzle was increased in difficulty by certain plates of slate with hunting and battle scenes and other representations in relief in a style so strange that many investigators considered them products of the art of western asia. the first light was thrown on the question in the winter of - by the excavations of flinders petrie in ballas and neggadeh, two places on the west bank of the nile, a little below ancient thebes. this persevering english investigator discovered here a very large necropolis in which he examined about three thousand graves. they all contained the same kinds of pottery and the same slate tablets mentioned above, and many other objects which did not seem to be egyptian. it was plain that the newly found necropolis and the puzzling objects already in the museums belonged to the same period. petrie assumed that they represented the art of a foreign people--perhaps the libyans--who had temporarily resided in egypt in the time between the old and the middle kingdoms. he gave this unknown people the name "new race." but his theory met with little approval, least of all from german egyptologists; and even at that time, an opinion was expressed that this unusual art belonged before the known beginning of egyptian culture. however, in spite of much discussion, the question could not then be decided. about the same time another riddle was presented to egyptologists by the results of the excavations made in abydos by the french scholar amélineau; and another hot discussion was raised. amélineau had excavated several large tombs and had also found objects which could not be arranged in the known development of egyptian art. the fortunate discoverer ascribed these to the dynasties of the demigods, who, according to egyptian tradition, reigned before the kings; but of course this idea met with determined opposition, and indeed especially among his french colleagues. the tomb of abydos offered, however, on quiet consideration, more material for establishing its date than those of ballas and neggadeh. in abydos a number of inscriptions had been found which, rude as they were, showed that the people buried in the tombs had known the hieroglyphic system of writing. the occurrence of so-called "horus names" in these inscriptions was especially important. for every old egyptian king had a long list of names and titles, and among them a name surmounted by the picture of a hawk (i.e., horus), and called on that account the "horus name." as the name is, at the same time, written on a sort of standard, it is also called the "banner name." such "horus" or "banner names" occur, then, on the objects found by amélineau. accidentally, one of these names occurs, also, on a statue in the grizeh museum which, according to its style, is one of the oldest statues which the museum possesses. thus it became evident that the abydos objects were, in any case, to be placed in the earliest period of egyptian history. the discussion stood thus when, in the spring of , the fortunate hand of de morgan, the former directeur-général des services des antiquités égyptiennes, succeeded by renewed excavations in neggadeh in furnishing the connections between the objects found by petrie in ballas and neggadeh and those found by amélineau in abydos. he discovered, not far from the necropolis, excavated by petrie, the tomb of a king which, on the one hand, contained pottery and tablets like those found by petrie, and on the other, objects entirely like those found by amélineau. thus it was proved that both petrie's tombs and those of amélineau belonged to the same period, and, indeed, the oldest period, of egyptian history, before the third dynasty. they were older than the most ancient objects which we had thought that we possessed. but it was still impossible to date them exactly. at this point, an epoch-making discovery of dr. sethe, privat-docent at the university of berlin, placed the whole matter at a single stroke on a comparatively sure foundation. he pointed out that the inscriptions on a few unassuming potsherds from abydos contained not only banner names of old kings, but also their ordinary names. these names were not inclosed, as later, in cartouches, and even contained many unusual spellings; but they were still too clear to be misunderstood. sethe succeeded in identifying the names of the fifth, the sixth and the seventh kings of the first manethonian dynasty, called by the greek authors usaphais, miebais and semempses. thus it became extremely probable that all these newly discovered objects were from the first dynasty, but still not absolutely certain; for the three names occurred only on fragments of vases, and absolutely nothing was known of how these fragments were found. the proof that they belonged to the other objects was wanting. a very skeptical investigator might still have said that the other objects were older, that the potsherds had only fallen accidentally into ruined tombs of an older period; or he might have said quite the contrary, that the potsherds were older than the tombs. at this point occurred the possibility of finding a solution of the question in the objects found in the royal tomb of neggadeh. for the report of the excavations at neggadeh was more exact than that of the excavations at abydos; and the whole contents of the tomb of neggadeh had been kept together and preserved in a separate room in the grizeh museum. the possibility became a reality. one of the principal objects of this royal tomb was found to bear the ordinary as well as the horus name of the king--a fact which had escaped the fortunate discoverer. the object is a small ivory plate with incised representations of funerary offerings before the king. animals are being sacrificed to him; jars full of beer and other things are being offered. the figure of the king, in front of a hanging mat, is not preserved; but the upper corner still remains with the two names, which were written above the figure. first, there is the same horus name which occurs on all the inscribed objects of this tomb and which may be translated "the warrior." beside the horus name in a sort of cartouche is the title "lord of vulture and serpent crown" (lord of upper and lower egypt), and beneath the title the sign which represents a checkerboard, and has the syllabic value mn. there can therefore be no doubt that the king buried in the royal tomb of neggadeh, of whom we had only known the horus name "the warrior," had also the name mn. now, there is no other known egyptian king who could be identified with this name mn than the first king of the first manethonian dynasty, called menes by the greeks. it is impossible here to go into the philological basis of the identification of mn and menes. the final conclusion is this: in neggadeh, we have before us the tomb of the oldest king of whom the egyptians had preserved any memory, and whom they considered the founder of the egyptian monarchy. in consideration of the importance of the questions involved, a short description of the tomb of menes and of the objects found in it will certainly be of interest. the second part of de morgan's book, "recherche sur les origines de l'egypte," which has just appeared, furnishes us with the facts concerning the tomb, and the objects found in the tomb i will describe from the originals in the gizeh museum. the tomb consists of a large building, standing alone, measuring x m. (about x egyptian ells), and built of burned brick. the outside walls were ornamented, as was usual in later egyptian buildings, with pilasters composed of groups of smaller rectangular pilasters. it is the same motive so often to be observed in the sham doors in tombs of the old kingdom, and is really the most natural facade ornamentation for brick buildings, as it may be made by simply setting every alternate column of bricks forward or backward. the walls were, in addition, plastered. back of the thick outside wall on each side lay a row of narrow rectangular rooms, formed by dividing a corridor by means of cross walls. inside this surrounding row of rooms was the real tomb, a building with thick walls and five rooms in a row. the middle one of these rooms, noticeably larger than the others, is the real burial chamber. these five rooms were originally connected by doors which were afterward walled up. as to the roof, we can only make surmises, as the excavator has furnished us with no material on this point. the walls as they now stand are at the highest point about four meters high, and thus may form only the lower part of the building. whether the roof was an arch of stone or simply of wood, is uncertain; but it seems to me probable that it was of wood. for the tomb contained a layer of ashes in which all the objects put in the grave with the dead man were found; and, assuming that the roof was of wood, it is possible that the roof was set on fire at the time when the tomb was robbed and that the ashes came from this fire. the explanation which the excavator gives of these ashes, that the body and the offerings were burned in the closed grave, hardly deserves consideration. in any case, the grave has been robbed and destroyed. that is shown by the fact that many pieces of funeral furniture, which originally could only have been put in the central rooms, were found partly broken in the outside rooms, or on the side toward the fields, the side most exposed to the attack of grave robbers. the assumption that the grave has been robbed and intentionally destroyed agrees entirely with the fact that all the more valuable objects found in the grave were in fragments. but, fragmentary as they are, they are sufficient to give us a good idea of the art of the first period of the egyptian kingdom, a period which is now most generally estimated to be five and a half millenniums before the present day ( b.c.) the skill with which ivory carving was done in that early time is indeed amazing. reclining lions, hunting dogs and fish are so skillfully reproduced that one asks how many centuries of development must have preceded before the art of carving reached this perfection. a number of feet taken from the legs of small chairs and other similar furniture, and made in imitation of bulls' legs, show such a fixity of style and at the same time such a freedom of execution, that no archæologist, without the report of the excavator, would dare to proclaim them the oldest dated works of egyptian art. but it was not only in carving ivory, which is easy to work, that the egyptian artists showed their skill. they also make bowls and vases of diorite and porphyry with the same success; and the forms presented by the smaller ivory vases are also to be found in vases made of those refractory stones. further, the vases made of stone present not merely such forms as might be made by turning or boring, but there are also bowls with ribs which are as finely polished as the turned bowls. the hardest material used in the objects already found is rock crystal, of which several small flasks and bowls and a little lion are composed. but the lion, it must be confessed, is rather rudely worked. a few small vases of obsidian also occur--remarkable in view of the fact that we do not know of any place in or near egypt where this stone may be found. besides these vessels of hard stone, there are, of course, a large number made of softer stone. alabaster vases occur in every conceivable form. cylindrical pots, with wavy handles or simple cordlike ornamentation, appear to have been especially favored. the great beer jars, closed with enormous stoppers of unbaked clay, were made of ordinary baked clay. of course the different stone and clay vessels, which, undoubtedly, originally contained offerings for the dead, form the bulk of the contents of the grave. the slate tablets for rubbing cosmetics for painting the body, and the flint weapons and knives of all sorts, follow in point of numbers. remarkably enough, metal objects occur in this oldest historical period alongside the stone implements, though, of course, in less numbers. several objects made of copper and a slender bead of gold have been found. such, in short, is all that remains of the things put in the tomb with the king. but little as there is, it gives us an idea of the richness and splendor with which these old royal tombs were furnished. it might certainly be productive of unusual emotions to know that the few human bones found in the tomb, and now preserved in the gizeh museum, once belonged to the oldest egyptian king. but as we know almost nothing of him, except some unfounded traditions, this sort of relic worship deserves very little respect. the scientific value of the proof that menes was the king buried in the royal tomb of neggadeh lies rather in the fact that we have now settled the question of the age of that culture which was presented to us by the excavations of ballas, neggadeh and abydos. the products of a whole period of egyptian civilization which had been misunderstood, and had been used to support false historical conclusions, fall into their true place; and our knowledge of the history of egyptian culture is carried back not merely a few centuries, but to a period presenting characteristics different from the oldest previously known period, but containing the germs of the later development. cairo, egypt. * * * * * rose psyche. the hybrid polyantha rose psyche is a seedling from the dwarf polyantha rose golden fairy, crossed with the pollen of the crimson rambler. its growth and habit, though more delicate, much resembles the rambler. it is apparently quite hardy, and is very free flowering, but we fear not perpetual. the flowers are produced in clusters of from fifteen to twenty-five, and are to ½ inches across when fully expanded. in the bud stage they are very pretty and well formed. the color is white, suffused with salmon-rose and pink, with a yellow base to the petals. it is a real companion to crimson rambler.--the gardeners' chronicle. [illustration: rose hybrid polyantha "psyche"--color, pale pink.] * * * * * sleep and the theories of its cause. the theory of the origin of sleep which has gained the widest credence is the one that attributes it to anæmia of the brain. it has been shown by mosso, and many others, that in men with defects of the cranial wall the volume of the brain decreases during sleep. at the same time, the volume of any limb increases as the peripheral parts of the body become turgid with blood. in dogs, the brain has been exposed, and the cortex of that organ has been observed to become anæmic during sleep. it is a matter of ordinary observation that in infants, during sleep, the volume of the brain becomes less, since the fontanelle is found to sink in. it has been supposed, but without sufficient evidence to justify the supposition, that this anæmia of the brain is the cause and not the sequence of sleep. the idea behind this supposition has been that, as the day draws to an end, the circulatory mechanism becomes fatigued, the vasomotor center exhausted, the tone of the blood vessels deficient, and the energy of the heart diminished, and the circulation to the cerebral arteries lessened. by means of a simple and accurate instrument (the hill-barnard sphygmometer), with which the pressure in the arteries of man can be easily reckoned, it has been recently determined that the arterial pressure falls just as greatly during bodily rest as during sleep. the ordinary pressure of the blood in the arteries of young and healthy men averages - mm. of mercury. in sleep, the pressure may sink to - mm.; but if the pressure be taken of the same subject lying in bed, and quietly engaged on mental work, it will be found to be no higher. by mental strain or muscular effort, the pressure is, however, immediately raised, and may then reach - mm. of mercury. it can be seen from considering these facts that the fall of pressure is concomitant with rest, rather than with sleep. as, moreover, it has been determined on strong evidence that the cerebral vessels are not supplied with vasomotor nerves, and that the cerebral circulation passively follows every change in the arterial pressure, it becomes evident that sleep cannot be occasioned by any active change in the cerebral vessels. this conclusion is borne out by the fact that to produce in the dog a condition of coma like to sleep, it is necessary to reduce, by a very great amount, the cerebral circulation. thus, both carotids and both vertebral arteries, can be frequently tied at one and the same time without either producing coma or any very marked symptoms. the circulation is, in such a case, maintained through other channels, such as branches from the superior intercostal arteries which enter the anterior spinal artery. while total anæmia of the brain instantaneously abolishes consciousness, partial anæmia is found to raise the excitability of the cortex cerebri. by estimation of the exchange of gases in the blood which enters and leaves the brain, it has been shown that the consumption of oxygen and the production of carbonic acid in that organ is not large. further, it may be noted that the condition of anæsthesia is not in all cases associated with cerebral anæmia. thus, while during chloroform anæsthesia the arterial pressure markedly falls, such is not the case during anæsthesia produced by ether or a mixture of nitrous oxide and oxygen. the arterial pressure of man is not lowered by the ordinary fatigue of daily life. it is only in extreme states of exhaustion that the pressure may be found decreased when the subject is in the standing position. the fall of pressure which does occur during rest or sleep is mainly occasioned by the diminished rate of the heart. the increase in the volume of the limbs is to be ascribed to the cessation of muscular movement and to the diminution in the amplitude of respiration. the duty of the heart is to deliver the blood to the capillaries. from the veins the blood is, for the most part, returned to the heart by the compressive action of the muscles, the constant change of posture and by the respiration acting both as a force and suction pump. all of these factors are at their maximum during bodily activity and at their minimum during rest. on exciting a sleeper by calling his name, or in any way disturbing him, the limbs, it has been recorded, decrease in volume while the brain expands. this is so because the respiration changes in depth, the heart quickens, the muscles alter in tone, as the subject stirs in his sleep in reflex response to external stimuli. considering all these facts, we must regard the fall of arterial pressure, the depression of the fontanelle, and the turgescence of the vessels of the limbs as phenomena concomitant with bodily rest and warmth, and we have no more right to assign the causation of sleep to cerebral anæmia than to any other alteration in the functions of the body, such as occur during sleep. we may well here summarize these other changes in function: ( ) the respiratory movement becomes shallow and thoracic in type. ( ) the volume of the air inspired per minute is lessened by one-half to two-thirds. ( ) the output of carbonic acid is diminished by the same amount. ( ) the bodily temperature falls. ( ) the acidity of the cortex of the brain disappears. ( ) reflex action persists; the knee jerk is diminished, pointing to relaxation in tone of the muscles; consciousness is suspended. analyzing more closely the conditions of the central nervous system, it becomes evident that, in sleep, consciousness alone is in abeyance. the nerves and the special senses continue to transmit impulses and to produce reflex movements. if a blanket, sufficiently heavy to impede respiration, be placed upon the face of a sleeping person, we know that it will be immediately pushed away. more than this, complicated movements can be carried out; the postilion can sleep on horseback; the punkah-wallah may work his punkah and at the same time enjoy a slumber; a weary mother may sleep, and yet automatically rock her infant's cradle. turning to the histories of sleep walkers, we find it recorded that, during sleep, they perform such feats as climbing slanting roofs or walking across dangerous narrow ledges and bridges. the writer knew of the case of a lad who, when locked in his room at night to prevent his wandering in his sleep, climbed a partition eight to ten feet in height which separated his sleeping compartment from the next, and this without waking. the brain can carry out not only such complicated acts as these, but it has been found to maintain during sleep its normal inhibitory control over the lower reflex centers in the spinal cord. thus, in sleeping dogs, after the spinal cord has been divided in the dorsal region, reflexes can be more easily evoked from the lumbar than from the cervical cord, because the former is freed from the inhibitory control of the brain. the strength of stimulus necessary to pass the threshold of consciousness and to produce an awakening has been measured in various ways. it has been determined that it takes a louder and louder sound or a stronger and stronger electric shock to arouse a sleeper during the first two or three hours of slumber; after that period, the sleep becomes lighter and the required stimulus need be much less. the alternative theories which have been suggested to account for the onset of sleep may be classed as chemical and histological. in relation to the first, it has been suggested that if consciousness be regarded as dependent upon a certain rate of atomic vibration, it is possible that this rate depends on a store of intramolecular oxygen, which, owing to fatigue, may become exhausted; or it may be supposed that alkaloidal substances may collect as fatigue products within the brain, and choke the activity of that organ. against this theory may be submitted the facts that monotony of stimulus will produce sleep in an unfatigued person, that over-fatigue, either mental or bodily, will hinder the onset of sleep, that the cessation of external stimuli by itself produces sleep. as an example of this last, may be quoted the case recorded by strumpel of a patient who was completely anæsthetic save for one eye and one ear, and who fell asleep when these were closed. moreover, many men possess the power, by an effort of will, of withdrawing from objective or subjective stimuli, and of thus inducing sleep. the histological theories of sleep are founded on recent extraordinary advances in the knowledge of the minute anatomy of the central nervous system, a knowledge founded on the golgi and methylene blue methods of staining. it is held possible that the dendrites or branching processes of nerve cells are contractile, and that they, by pulling themselves apart, break the association pathways which are formed by the interlacing or synapses of the dendrites in the brain. ramon y cajal, on the other hand, believes that the neuroglia cells are contractile, and may expand so as to interpose their branches as insulating material between the synapses formed by the dendrites of the nerve cells. the difficulty of accepting these theories is that nobody can locate consciousness to any particular group of nerve cells. moreover, the anatomical evidence of such changes taking place is at present of the flimsiest character. if these theories be true, what, it may be asked, is the agency that causes the dendrites to contract or the neuroglia cells to expand? is there really a soul sitting aloof in the pineal gland, as descartes held? when a man like lord brougham can at any moment shut himself away from the outer world and fall asleep, does his soul break the dendritic contacts between cell and cell; and when he awakes, does it make contacts and switch the impulses evoked by sense stimuli on to one or other tract of the axons, or axis cylinder processes, which form the association pathways? such a hypothesis is no explanation; it simply puts back the whole question a step further, and leaves it wrapped in mystery. it cannot be fatigue that produces the hypothetical interruptions of the dendritic synapses and then induces sleep, for sleep can follow after fatigue of a very limited kind. a man may sleep equally well after a day spent in scientific research as after one spent in mountain climbing, or after another passed in idling by the seashore. he may spend a whole day engaged in mathematical calculation or in painting a landscape. he fatigues--if we admit the localization of function to definite parts of the brain--but one set of association tracts, but one group of cells, and yet, when he falls asleep, consciousness is not partially, but totally suspended. we must admit that the withdrawal of stimuli, or their monotonous repetition, are factors which do undoubtedly stand out as primary causes of sleep. we may suppose, if we like, that consciousness depends upon a certain rate of vibration which takes place in the brain structure. this vibration is maintained by the stimuli of the present, which awaken memories of former stimuli, and are themselves at the same time modified by these. by each impulse streaming into the brain from the sense organs, we can imagine the structure of the cerebral cortex to be more or less permanently altered. the impulses of the present, as they sweep through the association pathways, arouse memories of the past; but in what way this is brought about is outside the range of explanation. perhaps an impulse vibrating at a certain rate may arouse cells or fibrils tuned by past stimuli to respond to this particular rate of vibration. thus may be evoked a chain of memories, while by an impulse of a different rate quite another set of memories may be started. tracts of association are probably formed in definite lines through the nervous system, as during the life of a child repeated waves of sense impulses beat against and overcome resistances, and make smooth pathways here and there through the brain structure. thus may be produced growth of axons in certain directions, and synapses of this cell with that. if the same stimulus be often repeated, the synapses between groups of cells may become permanent. a memory, a definite line of action which is manifested by a certain muscular response, may thus become structurally fixed. if the stimulus be not repeated, the synapses may be but temporary, and the memory fade as the group of cells is occupied by a new memory of some more potent sense stimulus. many association tracts and synapses are laid down in the central nervous system when the child is born. these are the fruits of inheritance, and by their means, we may suppose, instinctive reflex actions are carried out. so long as the present stimuli are controlled by past memories and are active in recalling them, so long does consciousness exist, and the higher will be the consciousness, the greater the number and the more intense the character of the memories aroused. we may suppose that when all external stimuli are withdrawn, or the brain soothed by monotony of gentle repetition, and when the body is placed at rest, and the viscera are normal and give rise to no disturbing sensations, consciousness is then suspended, and natural sleep ensues. either local fatigue of the muscles, or of the heart, or ennui, or exhaustion of some brain center usually leads us to seek those conditions in which sleep comes. the whole organism may sleep for the sake of the part. to avoid sleeplessness, we seek monotony of stimulus, either objective or subjective. in the latter case, we dwell on some monotonous memory picture, such as sheep passing one by one through a gap in the hedge. to obtain our object, we dismiss painful or exciting thoughts, keep the viscera in health, so that they may not force themselves upon our attention, and render the sense organs quiet by seeking darkness, silence and warmth.--l.h., in nature. * * * * * amateur chronophotographic apparatus. at the time that we described the demeny chronophotographic apparatus we remarked that it had the advantage of permitting of the projection of very luminous images of large dimensions; but it is certain that the cases are somewhat limited in which there is any need of using a screen or feet square, and, as a general thing, one or feet square suffices. the manufacturer of the apparatus, m. gaumont, has, therefore, been led to construct a small size in which the bands have the dimensions usually employed in the french and other apparatus, thus permitting of the use of such as are now found in abundance in the market. by reducing the size, it has been possible further to simplify the construction, and at the same time to reduce the price, thus making of the new form a genuine amateur apparatus. it will be remembered that the demeny principle consists especially in the avoiding of traction upon the perforated part of the band, which is the portion that always presents the most fragility. this principle has naturally been preserved in the small model, and a preservation of the bands for a long time is thus assured. [illustration: fig. --arrangement of the sensitized band in two magazines.] [illustration: fig. --arrangement for taking views with special gearing for the winding of the band.] the apparatus is reversible, and may be used for making negatives as well as for projecting positives. in its new form it is easily transportable and is no more bulky than an ordinary by inch apparatus. nothing is simpler then than to carry it on a journey, if one desires to make his own negative bands. since the sensitized film has to be protected against the light during its entire travel, two magazines have been arranged (fig. ). one of these, a, which is fixed upon the top of the camera, contains the clean film, while the other, b, which is placed beneath the objective, receives the strip after it has been acted upon by the light. a train of toothed wheels, c (fig. ), actuates the roller of this second magazine. this arrangement may, moreover, be utilized also when projections are made, if one does not desire the band to float in measure as it unwinds behind the objective. as the upper magazine is entirely closed when it is placed upon the apparatus, it is necessary, in order to prepare for taking a negative, to pull out a few inches of the film, pass the latter over the guide roller and fix the extremity to the winding roller in the lower magazine. it is clear that we can have any number of magazines whatever for carrying about, all charged, just as one carries the frames of his ordinary camera. chronophotography presents no more difficulty than ordinary photography as regards the taking of negatives, and the amateur who has not the proper facilities for developing and printing the latter can have these operations performed by a professional. animate projections are beginning to be introduced into parlors, and some day will entirely replace the magic lantern therein. the excitement caused by the catastrophe at the charity bazar is now calmed, and it has been ascertained that the accident was not due to the lamp of the projector, but to a carelessly handled can of ether. so the extension of this sort of spectacle, momentarily arrested, is taking a new impetus, which will be further aided by the apparatus under consideration, for the description of which and the illustrations we are indebted to la nature. * * * * * the reclaiming of old rubber. by hawthorne hill. the complaint of high prices of india rubber is as old as the rubber industry, one result of which has been an unceasing effort to discover a practical substitute. never was the secret of the transmutation of metals sought more persistently by ancient philosophers than the secret of an artificial rubber has been by modern chemists, but, thus far, the one search has been hardly more successful than the other. one discovery has been made, however, by which our rubber supplies have been so far conserved that, for the want of it, we might be obliged now to pay double the current prices for new rubber. this is the reclaiming of rubber from worn-out goods, in a condition fit for use again in almost every class of products of the rubber factory. soon after the vulcanization of rubber became fully established, attempts began to be made to "devulcanize" the scrap and cuttings of rubber which accumulated in the factories. so extensive were these accumulations that one company are reported to have built a road with rubber scrap through a swamp adjacent to their factory, while most other manufacturers were unable to find even so profitable a use for their wastes. as time advanced there came to be large stocks, also, of worn-out rubber goods, such as car springs and the like, all of which appealed to a practical mind here and there as being of possible value, since the price of new rubber kept climbing up all the while. no fewer than nineteen patents were granted in the united states for "improvements in devulcanizing india rubber," or "restoring waste vulcanized rubber," beginning in , or eleven years after the date of goodyear's patent for the vulcanization process. in that year francis baschnagel obtained a patent for restoring vulcanized rubber to a soft, plastic, workable state, by treating it with alcohol absolutus and carbon bisulphuratum, in a closed vessel, without the application of heat. later he obtained a patent for accomplishing the same result by "boiling waste rubber in water, after it has been reduced to a finely divided state;" and still later, one for treating the waste to the direct action of steam. patents were granted in to hiram l. hall, for the treatment of waste rubber by boiling in water; also, by subjecting it to steam; and again, by combining various resinous and other substances with it. the two inventors named assigned their patents to the beverly rubber company, of beverly, mass., controlled then by the proprietors of the new york belting and packing company, and their processes became the basis of an important business in rubber clothing. the low cost of the devulcanized rubber, as compared with new rubber, alone gave them a great advantage over other manufacturers, in addition to which they escaped the payment of a license to work under the goodyear patents. many army blankets, made for the government during the civil war, were waterproofed with hall's devulcanized rubber, and from that period little new rubber has been used in the manufacture of heavy rubber coats. the other patents in this class do not deserve special mention. it having been established that rubber is rubber, no matter where found, manufacturers gradually turned their attention beyond the scraps and cuttings which remained after making up their goods. there was beginning to be a good demand for ground-up rubber car springs, wringer rolls, tubing and other rubber goods free from fiber, after it had been so treated as to remove the sulphur contents and restore the gum to a workable condition. but this left out of account rubber footwear, belting, and hose, not to mention the later heavy production of bicycle tires. there were only a few uses to which rubber waste containing fibrous material could be put when ground up and devulcanized without the removal of the fiber. it could be put into a cheap grade of steam packing or mixed in a powdered form with new rubber for the heels of rubber boots and shoes. there was an early patent for a process for "combining fibrous materials with waste vulcanized rubber, rendered soft and plastic." but all the other patents which come within the scope of this article had for their object the separation of fibers from the rubber. an important advance was marked by the hayward patent (no. , ), granted in , for "boiling waste rags of fibrous material and rubber in an acid or alkali, for the purpose of destroying the tenacity of the fibers of the rags, so that the rubber may be reground." but this process extended only to the weakening of the fibers, and not their complete destruction. a later patent, in the same year, provided for exposing the ground rubber waste to the direct action of flames of gas or inflammable liquids, by which the foreign matters would be consumed and the rubber rendered plastic and cohesive, but it is not on record that this process received any particular application. the principal activity of invention in the field of reclaiming rubber dates from , since which year patents have been granted for processes more or less distinctive from those which had for their object only the devulcanization of rubber. prior to that time the use of rubber reclaimed from fibrous wastes had been confined practically to one large factory in boston and one near new york. one concern, for a while, bought old rubber shoes and sent them to women in the country, whom they paid so much a pound for the rubber stripped off--a very expensive process. there were several claimants for priority in the matter of reclaiming rubber by the processes which finally became standard, and some conflicting interests were brought together under the head of the chemical rubber company. this corporation controlled the leading patents for the "acid" process, licensing various parties to work under them, and bringing suits against concerns who reclaimed rubber without their license. in the united states courts decided in favor of the defendants, practically rendering the patents invalid, on the ground that the inventions claimed under them had been disclosed by the hall patents of and the hayward patent of . the two patents upon which the suits for infringement rested principally were no. , , granted to n.c. mitchell, in , and no. , , granted to the same, in . about the same time the rubber reclaiming company, formed in by the combination of five leading rubber reclaiming plants, and working under license from the company above named, was resolved into the original elements. there were about that time five other rubber reclaiming plants in the united states, operating either the "acid" or the "mechanical" process, besides nine general rubber factories producing their own reclaimed rubber by the "acid" process. while several of the latter--rubber shoe concerns controlled by the united states rubber company--have been consolidated, there has been an increase in the number of rubber manufacturers reclaiming their own rubber, since the end of the patent litigation, so that the total number of reclaiming plants now probably is twenty. the first step in any process for reclaiming rubber is the grinding of the waste, for which purpose several machines have been designed specially, an early patent for disintegrating rubber scrap by "subjecting it to the abrading action of grindstones" having failed to meet with favor. the most usual chemical treatment is a bath in a solution of sulphuric acid in lead-lined tanks. generally heat is employed to hasten the process, through the medium of steam, in which case the tanks are tightly closed. the next step is the washing of the scrap, to free it of acid and dirt, after which it is sheeted by being run between iron rollers and hung in drying rooms. as soon as it has become dry it is ready for sale. in the extended litigation over the acid process patents, the points at issue related to the strength of the acid named in the various specifications and also to the methods of applying steam. prof. charles f. chandler, called as an expert in one case, testified that the effects of acids, such as sulphuric or hydrochloric, upon rubber and rubber compounds, under varying strength and temperature, had been known at a period antedating all the patents then the basis of suits for infringement; also that their effect upon cotton and woolen fabrics had been equally well known. they had the same effect upon fibers, whether the latter were combined with rubber or not, but very strong acids would affect the rubber injuriously. the line of defense in this case was that "no invention was required in selecting the strength of acid; only the common sense of the manufacturer, aided by his skill and experience, was necessary to bring about the proper results." in support of this a factory superintendent testified that varied stocks required skill and judgment in their treatment and more or less variation as to the strength of acid, temperature, etc. as to the use of steam, prof. henry b. cornwall, of princeton college, called as an expert in another case, testified that, having put to a test the specifications in all the patents involved, he had found it necessary in no case to inject live steam into the mixtures of acid and rubber scrap in order to effect the decomposition and removal of either woolen or cotton fiber. the use of the acids specified was sufficient for this, and the various high temperatures called for were not essential for the destruction of the fibers. he neglected to mention, however, that the steam served an equally important purpose in devulcanizing the rubber. it appeared that the practice in different factories had included the use of sulphuric acid varying from a ½ per cent. solution to the full commercial strength of the acid, but one of the defendant companies based their case upon their use of acid of the strength of ° to ° baumé, whereas the patent they were charged with infringing specified a strength of °. their tanks were lead-lined and provided on the interior with steam pipes running down the sides and along the bottom, the sections at the bottom being perforated and the steam admitted at a pressure of to pounds. the chemical treatment lasted from ½ to hours. the sulphuric acid treatment, however, is confined mainly to scrap containing cotton fiber. where woolen fibers occur, which is much less frequently, their disintegration is accomplished generally by the use of caustic soda. in the mechanical process of reclaiming rubber, the rubber is separated from the fiber, after the whole has been finely ground, by means of an air blast, the method being not unlike that practiced by furriers for separating hair and fur from bits of pelt after skins have been finely divided. as the powdered waste comes from the blower, the rubber falls in a heap near the machine, while the particles of fiber, being lighter, are carried far enough away to make the separation complete. devulcanization in this case is effected by exposure to live steam at a high temperature. no oil is used in the process, the sheeting of the product being facilitated by means of hot friction rollers. the cost of reclaiming rubber by the acid process is less than by mechanical means, for which reason the former is now much more generally used. but some manufacturers are willing to pay more per pound for mechanically-reclaimed rubber, either ( ) because it can be "compounded" more heavily than the acid product, or ( ) because of certain inherent disadvantages of the latter. it is the testimony of these manufacturers that the action of sulphuric acid upon whiting (one of the most common adulterants used in rubber shoes) is to turn it into sulphate of lime--an ingredient which is far from advantageous in a rubber compound. again, any acid which may remain in the reclaimed rubber is liable to rot thin textile fabrics with which it may be combined in manufacture. finally, rubber recovered by the chemical process, it is claimed, is harder than that obtained by any other; so that it is usual to add, during vulcanization, in order to soften the product, the residuum obtained from petroleum manufactures, or palm or other oils. unvulcanized rubber clippings also have been used for this purpose. one of the most successful of our rubber factory superintendents, who formerly made the reclaimed rubber used by his factory, has stated that his practice was to subject the material to an alkaline bath after the acid treatment, not only for the better cleaning of the rubber, but to neutralize any acid which might remain. considering all the points involved, it was his opinion that, when scrap rubber is cheap, the mechanical process is the more economical, while, if it is high priced, the acid process has the advantage. since this expression of opinion, however, prices of rubber scrap have ranged constantly at higher figures than before, and there is no indication that we shall have again what was known formerly as "cheap" scrap. it is not surprising, therefore, that the volume of mechanical "shoddy" should be placed by the best estimates at not above one-sixth of the total production of reclaimed rubber in the united states. and the acid product, with all its admitted shortcomings, is still superior to any of the so-called rubber substitutes. reclaimed rubber is not to be considered as an adulterant, except in the same sense as fillings, like whiting, litharge or barytes, the use of which in rubber compounds often gives to the product desirable qualities that are unobtainable by the use of "pure gum." it lacks some of the qualities of good native rubber, and yet it is rubber, and fills its proper place as acceptably as any raw material of manufacture. rubber shoes made of new gum entirely would be too elastic, and for that reason would draw the feet, besides being too costly for the ordinary trade. the construction of a rubber shoe, by the way, is well adapted for the use of different compounds for the different parts. rubber enters into twenty-six pieces of a rubber boot and nine or more pieces of a rubber shoe. consequently, as many different compounds may be used, if desired, for the output of a single factory for rubber footwear. the highest grades of native rubber may be used for waterproofing the uppers of a fine overshoe, while reclaimed rubber, of a cheap class even, may be good enough for the heel, which requires only to be waterproof and durable, without too much weight, and with no elasticity. reclaimed rubber goes into many classes of goods of high grade. the result is that such goods have been cheapened legitimately, placing them within the reach of immense numbers of consumers who otherwise would be obliged to do without. while the extensive use of reclaimed rubber is a matter of common knowledge to all who are familiar with the rubber industry, there are nowhere available any statistics of either the absolute or comparative volume of its consumption, with the single exception of the official returns of imports into canada. there separate accounts are kept of crude india rubber and of recovered rubber received in each year, and as only a consuming market exists for these commodities in the dominion, the figures given below may be taken to represent closely the actual consumption by the rubber factories of ontario and quebec. it is interesting to note the heavy growth of the percentage of recovered rubber shown in the table, all the figures representing pounds: fiscal crude recovered total year. rubber. rubber. imports. - , , , - , , , - , , , , , - , , , , , - , , , , , - , , , , , - , , , , , - , , , , , - , , , , , - , , , , , - , , , , , - , , , , , , percentage, - . . " - . . if it were possible to examine the books of the several rubber reclaiming plants on this side of the border, including rubber shoe and mechanical goods factories producing their own reclaimed rubber, the percentage of this material used, in comparison with the total rubber consumption, might be found to be as great in the united states as in canada. the rubber manufacture in the dominion, in its inception, was practically an offshoot from the industry in this country. our manufacturers supplied the canadian demand for rubber goods until, under the stimulus of heavy protective duties, rubber works were established beyond the border, since which time, to quote a leader in the trade in the united states, "the methods of the dominion rubber industry have mirrored the best practice in our country." hence it seems not unreasonable to conclude that if the canadians are using so large a percentage of reclaimed rubber, they are doing no more nor less than the older and larger concerns here. the most trustworthy authorities place the consumption of new rubber in the united states during at not far from , , pounds. assuming that the rate of consumption of reclaimed rubber was as great as in canada, we have , , pounds more, or a total of , , pounds. but there are producers of reclaimed rubber who insist that the amount of this material used in this country equals, pound for pound, the consumption of new rubber. the use of reclaimed rubber in europe is increasing gradually, and especially in great britain. the american product is sold extensively in that country, and some native reclaiming plants have been started. the most extensive "galosh" factory in russia, which is said to be the largest in the world, is reclaiming rubber according to american methods. but, as a rule, the continental rubber manufacturers make more use of "substitutes," a class of materials which has not found favor in america. these rubber substitutes belong chiefly to the class of oxidized oils and may be classed in three divisions: those obtained ( ) by the action of oxygen or air on linseed oil; ( ) by acting on rape oil with chloride of sulphur; and ( ) by the action of sulphur on rape oil at a high temperature. the first class has little application to the rubber trade, though its use is universal in the linoleum industry. in europe the chemist holds a more important position in the rubber manufacture than here, one result of which has been cheaper compounds of rubber and another the satisfactory employment of the refractory african rubbers long before they were used extensively in the united states. hence the cost of raw materials in the rubber industry has been, on the whole, cheaper abroad. the europeans have had an advantage, too, in respect to cheaper labor, which has offset somewhat our own advantage from the use of reclaimed rubber as a cheap material. there are numerous grades of reclaimed rubber, due to differences in the quality of stock used, and also to the different degrees of care used in its preparation, according to the requirements of manufacturers. the declared value of reclaimed rubber exported from new york during july, , averaged . cents per pound, while the value of exports for september averaged only . cents. the average value for the eight months ending february , , was . cents per pound. the total declared value of such exports for the fiscal year - was $ , , which, at the prices prevailing since, would represent considerably more than , , pounds. some of the material sold at home is known to bring less than any prices quoted above. "mechanical" stock brings about two cents per pound more than "acid" stock of corresponding grade. the collection of old rubber has acquired large proportions as an adjunct to the trade in junk or rags. not long ago the estimated yearly collection of rubber shoes alone amounted to , tons, and since that time the business in bicycle tire scrap has also become very large. during the past ten years the price of old rubber shoes has ranged between $ and $ per ton in carload lots, being at present about $ per ton. some , tons of rubber scrap are imported annually by the reclaiming companies in the united states. * * * * * in the baltic sea there are more wrecks than in any other place in the world. the average throughout the year is one each day. * * * * * engineering notes. the austrian government has ordered thirty-seven engines arranged to burn kerosene, for use in the arlberg tunnel, in which lack of proper ventilation at present causes the tunnel to remain filled with smoke.--uhland's wochenschrift. one of the first essentials to modern military enterprise is the establishment of a military railway system for war purposes. to be in a position to carry out efficiently and speedily what we may expect to be called upon to do on the outbreak of serious war, previous preparation in time of peace is an absolute requisite. in connection with general sherman's operations in georgia, during the american civil war, an army was supplied for six and a half months over a line miles long. the corps of workmen was , strong, and on one occasion replaced , sleepers and nine miles of rails in seven days. the true defense of the line was effected by the engineers always having men and material ready. in spite of the large and skilled railway population on which the army could call, and of the fact that practically the nation was in arms, it was found extremely difficult to keep this railway construction corps together until they were placed under a severe military discipline.--united service gazette. a hospital car has been introduced on the belgian railroads, says the engineer. it is designed for use in the event of a serious railway accident, and can be run to the spot where the wounded may be picked up and carried to the nearest city for treatment, instead of being left to pass hours in some wayside station while awaiting surgical attendance. the interior of this car is divided into a main compartment, a corridor on one side and two small rooms at the end. the largest compartment, the hospital proper, contains twenty-four isolated beds on steel tubes hung upon powerful springs; each bed is provided with a small movable table, a cord serving to hold all the various small objects which may be needed, and each patient lies in front of two little windows, which may be closed or opened at will. the corridor on the outside of the hospital chamber leads to the linen closet and the doctor's apartment; in the latter is a large cupboard, the upper portion being used for drugs, while the lower is divided into two sections, one serving as a case for surgical instruments and the other as a receptacle for the doctor's folding bed. the dust collected from the smoke of some liege furnaces, burning coal raised from the neighboring mines, produces, when dissolved in hydrochloric acid, a solution from which considerable quantities of arsenic and several other metallic salts may be precipitated. commenting on this fact, ascertained by m.a. jorissen, m. francis maur asks whether this breathing of arsenic and other minerals in a finely divided state may not account for the singular immunity from epidemics enjoyed by certain industrial districts, such as that of saint etienne, and hopes that some mine doctor will throw additional light on the subject. in the meanwhile, it may be suggested that the ventilating effect of the numerous chimneys in iron making and other industrial centers has its due share in constantly driving off the vitiated air and replacing it by fresh quantities of pure air. at any rate, when pestilence was raging in the high and pleasant quarter of clifton, its inhabitants migrated to the low-lying and not overclean parish of st. philips, bristol, where the air is black from the smoke of numerous chimneys, but where also the mortality compared very favorably with that in the fashionable quarter. a two-speed movable sidewalk, of the blot, guyenet and de mocomble type, is to be used for conveying visitors at the paris exposition, says engineering news. it differs from those of chicago and berlin in the reduction of the weight of the moving platform by spacing the driving wheels . feet apart and using electricity as a motive power. the driving wheels are mounted in the bed of the track and impart motion to a central rail on the under side of the platform. bearing wheels, spaced about feet apart under this rail, also carry the platform, and the central rail supports one-half the total weight of the platform; small side wheels carry the other half on side tracks. this arrangement enables the platform, which is divided into sections and hinged, to pass around quite sharp curves. the high speed platform, feet inches wide, is supposed to move at the rate of ½ miles per hour on a ½-inch gage track; the slow platform is ½ inches wide, moves at half speed and runs on a - / -inch gage track. the whole structure will be elevated on girders carried by cast iron columns, with stations about feet apart. the high speed platform weighs pounds per lineal foot; and with passengers, nearly pounds per foot. the slow speed platform weighs about half this. the track will be about ½ miles long; the initial motive power is figured at h.p. and the carrying capacity at , per hour. the "schlamm," or mud, thrown down from the water of coal washing has hitherto been regarded as worthless, says the engineering and mining journal, except that sometimes a portion of the coal particles it contained have been separated and made of value by a washing process; but bergassessor haarmann, of friedrichsthal, has invented a new method for treating it dry and dividing it into two products, one of which, with low ash content, is distinguished by its granular nature, while the other contains a large proportion of ash and is of the fineness of flour. the former of these two products is, on account of its low ash content, useful for various purposes, and the latter constitutes a fuel quite ready for use in coal dust firing. the method is founded on the circumstances, hitherto lost sight of, that the incombustible constituents of the "schlamm" chiefly consist of clay which was formerly more or less dissolved in the wash water; and on the mud being dried and subjected to a suitable mechanical process, the clay falls into fine dust, while the coal particles, on the contrary, retain their granular nature. the method is carried out by drying the mud and a subsequent fine sifting, which effects a breaking up of the lumps that occur in the dried "schlamm," and a separation into the two products above named. the dust that falls through the sieve has a high ash content, being in the nature of flour, while what remains behind is granular and has a low ash content. it seems to us that this game is hardly worth the candle. * * * * * electrical notes. electricity at the paris exposition.--electricity will play a large part at the paris exposition of , says the revue technique. no less than , h.p. will be used for lighting and , h.p. for furnishing electric power to the various parts of the grounds. as far as possible all the machinery exhibited will be shown at work and for this purpose electric conductors will be laid down to all points on the grounds. the boiler plant will be located at the end of the champ de mars, and will occupy two spaces of x feet each, one being devoted to french boilers and the other to those of foreign makers. this plant will be in itself a very interesting exhibit. it is proposed to provide a capacity for evaporating not less than , pounds of water per hour. an interesting little plant in which the rise and fall of the tides is used as motive power for the generation of electricity is described in l'electricien. near ploumanach, on the northern coast of france, where the tides have a daily range of feet, a small fish pond separated from the sea by a dike is arranged with gates so that at high tide the water flows in and fills it, the gates closing automatically when the tide recedes. the machinery of an old grist mill is used to operate a small dynamo, which charges a storage battery and furnishes light for the fish industry there. another wheel in the same mill works an ice making machine, the whole being under the charge of one man. it is stated that the total daily expense for generating about , horse power hours is only $ . peat bogs as generators of electrical power are suggested by dr. frank in stahl und eisen. he says that the great peat bogs of north germany may be thus utilized, and figures that one acre of bog, averaging feet in thickness, contains about , tons of dried peat, or , tons per square mile; and square miles would be equivalent in heating power to the , , to , , tons of coal annually mined in germany. the bogs of the ems valley alone cover , square miles; and dr. frank proposes the erection in that district of a , horse power electric station, which would yearly consume , tons of peat, or the product of acres. he would use the electrical energy on the dortmund and emshaven canal, and for the manufacture of calcium carbide. the success attending an application of electric towing on the burgundy canal was such that two new applications of electricity to canal haulage and also for barge propulsion were made last year in the neighborhood of dijon, on the same canal, under the superintendence of m. gaillot, ingénieur des ponts et chaussées. in the method of haulage, says the london engineer, the receptor dynamo is mounted on a tricycle, to which the name of "electric horse" has been given, and which, running on the towing path, takes its current from an air line consisting of two wires, mounted five meters (nearly feet) above the surface. this "horse," which weighs two tons, and is guided by a driver mounted upon it through the front wheel, proceeds on the towing path like a traction engine; and the boats are connected with it by a rope, with automatic disengaging gear, in case the force of the stream or a gust of wind should drive a boat backward. speeds of from , to , meters (mean , yards) were obtained with the electric horse, towing from three to four boats, so that it is more suitable than the electric propeller for towage in rivers or very long reaches; but it requires a driver, while the propeller, with which speeds of from , to , meters (mean , yards) per hour were obtained, is worked by the bargee on board his boat. the towing path is not worn, and there is no occasion for a tow rope, which always causes difficulty when two boats cross one another. m. maillet and m. dufourny, belgian ingénieurs des ponts et chaussées, who watched the trials, conclude that a practical solution of the question depends upon the cost of producing the motive power; but they also consider that horse haulage on canals will soon be superseded by mechanical traction, based on the use of an automotive tricycle, working with petroleum or some other hydrocarbon, and capable of running on the tow path without requiring any fixed plant. it has long been known that feathers and hair are electrical bodies, but until recently we have had little information about their electrical properties or the conditions in which these properties are manifested. most of these phenomena were first observed by exner, and in the work of dr. schwarze are found collected a mass of facts that cannot fail to interest the physician and the biologist; besides, we find there a description of exner's apparatus which was used by schwarze in most of his experiments on electrical phenomena of this kind. by the side of gold leaf electroscopes we see a feather electroscope, which is fastened to its support by means of a silken thread. a feather waved through the air is positively electrified, while the air itself seems to be charged with negative electricity.... two feathers rubbed together in the natural position are so electrified that their lower surface is negative and the upper positive.... these experiments and others still have been utilized to study the vital relations of animals and the biological signification of these phenomena. most feathers stick together and remain so even after being dried; if they then are waved through the air, the barbs of the feather separate, owing to differences of electrification. no bird needs to attend to its plumage at the end of a long flight, for while the large feathers are positively electrified by friction against the air, the white down has become negative, and so there is attraction between it and the feathers. another consequence of this production of electricity during flight is that during winds, even the most violent, the plumage does not become ruffled, but rests tightly against the bird's body, for in this case the wing feathers, which overlap, rub against each other and become electrified in contrary senses. if the bird flies toward the ground, flapping its wings, it compresses the air below them, and, supposing that the wing feathers can bend aside, the experiments of exner show that by the friction the upper side of one feather and the lower side of that which is just above are electrified oppositely, the more powerfully as the rubbing is greater, which always causes them to resume the normal position.--l'electricien. * * * * * selected formulÆ. removal of ink from hectograph.--it is recommended in südd. ap. ztg. to pour crude hydrochloric acid upon the hectograph, rub with a wad of cotton, then wash off by holding under cold running water and drying with a cloth. the hectograph may be used again immediately. to clean wall paper.--four ounces of pumice stone in fine powder are thoroughly mixed with quart of flour and the mass is kneaded with water enough to form a thick dough. this dough is formed into rolls about inches in diameter and or inches long; each one is sewed up in a piece of cotton cloth and then boiled in water for from to minutes--long enough to render the dough firm. after cooling and allowing the rolls to stand for several hours, the outer portion is peeled off and they are then ready for use, the paper being rubbed with them as in the bread process.--druggist's circular. insulating compound.--prof. fessenden recommends for armature work a compound made by boiling pure linseed oil at about degrees with / per cent. of borate of manganese, the boiling being continued for several hours, or until the oil begins to thicken. an advantage of this borated oil is that it always retains a slight stickiness, and so gives a good joint when wrapped around wires, etc. many substances so used are not sticky and let moisture in through the joints. where a smooth surface is required, it is readily obtained by dusting on a little talc. it can also be given a coat of japan on the outside.--american electrician. how to clean diatoms.--as a general rule, we may say that every specimen of diatomaceous earth or rock needs a special treatment. the following, however, may serve as a basic treatment, from which such departure may be taken in each case as the nature of the specimen would indicate: boil the material in hydrochloric acid, in a test tube, from two to five minutes. let settle, pour off the hydrochloric acid, substitute nitric acid in its place, and boil again for two or three minutes. pour into a beaker of water, stir a moment with a glass rod and let settle. after the material has fallen to the bottom, decant the liquid, and fill with fresh water. repeat the operation until the water no longer shows an acid reaction. a portion of the deposit may now be examined, and if not clean, boil the deposit with tincture of soap and water in equal parts, decant, wash, first with water, then with stronger ammonia water, and finally, with distilled water. this usually leaves the frustules bright and sharp.--national druggist. red indelible ink.--it is said that by proceeding according to the following formula, an intense purple red color may be produced on fabrics, which is indelible in the customary sense of the word. no. . sodium carbonate drs. gum arabic " water " no. . platinic chloride dr. distilled water oz. no. . stannous chloride dr. distilled water " moisten the place to be written upon with no. and rub a warm iron over it until dry; then write with no. , and, when dry, moisten with no. . an intense and beautiful purple-red color is produced in this way. the following simpler and less expensive method of obtaining an indelible red mark on linen has been proposed by wegler: dilute egg albumen with an equal weight of water, rapidly stir with a glass rod until it foams, and then filter through linen. mix the filtrate with a sufficient quantity of finely levigated vermilion until a rather thick liquid is obtained. write with a quill, or gold pen, and then touch the reverse side of the fabric with a hot iron, coagulating the albumen. it is claimed that marks so made are affected by neither soaps, acids nor alkalies. this ink, or rather paint, is said to keep moderately well in securely stoppered bottles, but we should not rely on it as a "stock" article. a white paint for marking dark colored articles might be made by substituting zinc white for the red pigment in the foregoing formula.--druggist's circular. brown or black discoloration of silvered mirrors.--generally these spots are due to faulty manipulation, too great dilution of the silver solution, or touching the plates with the fingers after they have been cleaned. sometimes, however, they are due to chemical defects in the glass itself. in these cases, as a general thing, the discolorations occur only after several days--a faultless mirror having been made at first, and the browning subsequently developing slowly. the writer was a student in the laboratory of baron liebig during the time that distinguished chemist was carrying out the series of experiments which resulted in devising a method of making silver mirrors commercially. one of the greatest troubles with which he had to contend was this browning--the cause for which was never fully cleared up by him. some years ago, the writer, having in his possession two mirrors made by liebig, and which had gradually become brown throughout, undertook an examination of the deposit (which had been thoroughly protected from extraneous influences by a strong film of varnish), and was surprised to find that it consisted of a layer of silver sulphide. without going into detail, the source of the change was later found to lie within the glass itself. in making glass to be used for mirrors, a considerable portion of sodium sulphate is used, and in annealing, this is partly reduced to sodium sulphide, which effloresces on the surface of the glass. this efflorescence is, of course, removed on cleaning the glass before silvering; but it is found that, in many instances, on exposure of the mirror to the light for some time, a further efflorescence occurs, and it is this which produces the discoloration in cases such as we have cited. it has been suggested that the tendency to subsequent efflorescence may be corrected by boiling the plates, intended for silvering, for a couple of minutes, in a per cent. solution of sodium carbonate or bicarbonate. we have no experience with the process, however.--national druggist. * * * * * wild and domestic sheep in the berlin zoological garden. as a rule, domestic animals are accorded very little space in zoological gardens, but, although it is doubtless the first duty of these popular institutions to show visitors animals which live in a wild state in foreign lands, it is well, where there is sufficient space and adequate means, to extend the limits of the collection so as to include natives of our own woods and fields, thus enabling people of a great city who are unfamiliar with nature to form an idea of the changes wrought in animal life by the influence of man, for domestic animals are a great aid in the study of natural history. the accompanying engravings are reproductions of instantaneous photographs of occupants of the new sheep and goat house--mostly foreign breeds; but there are a few that belong to that south european-asiatic group which are looked upon as the progenitors of the domestic sheep: the mouflon, of sardinia and corsica (ovis musimon l.), which has a coat of brownish red, flecked with darker color; and the slender, long-legged, reddish-gray sheep of belochistan (ovis blanfordi hume). the first glance at these creatures convinces one that they are wild, not domestic sheep, an impression which is caused chiefly by the monotonous coloring and the dry, short coat, which bears no resemblance to the thick fleece of the tame sheep, although the eye is soon attracted by other differences, such as the shape of the tail, which is short and thick, and of the horns, which extend over the back and then turn inward, so that when the old ram is kept in captivity, it is necessary to cut off the points of the horns to prevent their boring into the flesh of its neck. horns of this shape form a strong contrast to those with snail-like windings and points standing away from the body. when looking at one of these sheep from the front, it will be noticed that the left horn turns to the right and the right horn to the left. [illustration: sardinian mouflon (ovis musimon l.)] [illustration: belochistan sheep (ovis blanfordi hume).] former authorities have been unwilling to admit that the domestic sheep have come from any species of wild sheep of the present time. they hold that they are the descendants of one or more species of wild sheep that are now extinct. recently, however, men have thought more deeply and freely on such subjects, and nehring and others have traced the modern tame sheep back to the mouflon, but not to him alone. it is thought that in this case, as with other domestic animals, there has been a mixture of species, and in this connection attention was directed to the transcaspian arkal, the argalis of the interior of asia and the north african species. dr. heck, director of the berlin zoological garden, thinks that the horns of the tame ram, which are turned outward, the points being directed away from the body, constitute one of the strongest proofs that the blood of the argalis and its extinct european ancestors--which are known only by the fossil remains--flows in the veins of all domestic sheep. the other characteristic marks of the domestic sheep--the wool and the length of the tail--vary greatly. the heath sheep--the little, contented, weather-hardened grazing sheep of the lüneburg and other heaths--belong to one of the oldest species, and their tails are as short and their horns as dark as those of the moufflon. a cross between these two breeds is not distinguishable, even in the second generation, as has been shown by the interesting experiments in the düsseldorf zoological garden. [illustration: heath sheep.] the little, black and red-spotted cameroons sheep, from the western coast of africa, have not a trace of wool. but why should they have? the negroes need no clothing, and, consequently, they have not bred sheep with wool; and, besides, such an animal could not live in the tropics, even if the black man were a much better stock raiser and breeder than he is. the mane on the neck, and breast of the cameroons ram reminds one of the north american sheep; but it must be remembered that the mouflon and arkal rams have this ornament quite clearly, although not so strongly defined. [illustration: cameroons sheep.] the large, short-bodied and long-legged sheep found in the interior of western and northern africa are a complete contrast to the short-legged, long-bodied little cameroons sheep. there is a very valuable pair of the former in the berlin zoological garden--the haussa sheep--which are very regularly marked, the front parts of their bodies being red and the hind parts white. they were brought from the neighborhood of say, on the middle niger, by the togo hinterland expedition. the ram has beautiful horns, and the ewe is distinguished by two strange, tassel-like pendants of skin that hang from her neck. this zoological garden also possesses a fine ram from the interior of tunis, which is similar in shape to the haussa ram, but has shorter horns and a heavier mane. its color is grayish black. [illustration: ram from tunis.] [illustration: haussa ram.] [illustration: haussa ewe.] dr. heck considers the long tail of the domestic sheep the chief impediment to the adoption of the theory of its descent from the short-tailed wild sheep. and yet, in sheep, this member is of secondary importance, for it varies greatly in form. the short-tailed heath sheep are just the opposite of the fat-tailed persian sheep, which are represented in a fabulous account as being obliged to draw their broad tails, that weighed pounds, behind them on wheels. these are the sheep that supply the astrakan and persian lamb which is so much worn now. the fur is caused to lie in peculiar waves or tight rings by sewing the newly born lamb in a tightly fitting covering which keeps the fur from being mussed. in the berlin zoological garden there is a very fine four-horned, fat-tailed ram, from the steppes on the lower volga. from this region come also the large-boned, fat-rumped sheep, which have a large mass of fat on each side of the stunted tail. in the illustration this peculiarity does not show well, on account of the thick winter wool. their color is red, with dirty white. when wissman and bumiller returned from their last expedition, they brought a fine ram of a different breed of fat-rumped sheep, which are raised by the kirghise, on the altai mountains. they are smaller than those from the steppes of the volga, but have finer wool, and evidently belong to a finer breed. as mutton tallow is very useful, and has been used even from the most ancient times by sheep raisers in the preparation of food, they prize sheep with these masses of fat on the tail and rump, which were purposely developed to the greatest possible degree. [illustration: fat-tailed sheep (four-horned ram).] [illustration: fat-rumped sheep.] the steinbock and the chamois, which live in the highest mountains, are still found, but other breeds, such as the argalis, which inhabited the foot hills and the high table lands, have disappeared, as europe has become more thickly populated. we know that they formerly lived there, by the fossil remains of the oldest pliocene in england (ovis savinii newton), of the caves of bones near stramberg in moravia (ovis argaloides nehring), and of the diluvial strata near puy-de-dôme mountain in the south of france (ovis antiqua pommerol). for the above and the accompanying illustrations we are indebted to daheim. * * * * * [continued from supplement, no. , page .] patents.[ ] [footnote : to be presented at the niagara falls meeting (june, ) of the american society of mechanical engineers, and forming part of vol. six of the transactions.] by james w. see, hamilton, ohio, member of the society. employers' rights. an invention, to be patented, must be applied for by the actual inventor, and in the absence of acts constituting a transfer, the patent, and all legal ownership in it, and all rights under it, go exclusively to the inventor. in the absence of express or implied contract, a mere employer of the inventor has no rights under the patent. only contracts or assignments give to the employer, or to anyone else, a license or a partial or entire ownership in the patent. the equity of this may be appreciated by examples. a journeyman carpenter invents an improvement in chronometer escapements and patents it. the man who owns the carpenter shop has no shadow of claim on or under this patent. again, the carpenter invents and patents an improvement in jack planes. the shop owner has no rights in or under the patent. again, the carpenter invents an improvement in window frames, and the shop owner has no rights. he has no right even to make the patented window frame without license. the shop owner, in merely employing the carpenter, acquires no rights to the carpenter's patented inventions. but there are cases in which an implied license would go to the shop owner. for instance, if the carpenter was employed on the mutual understanding that he was particularly ingenious in devising carpenter work, and capable of improving upon the products of the shop; and if in the course of his work he devised a new and patentable window frame, and developed it in connection with his employment and at the expense of his employer; and if the new frames were made by the employer without protest from the carpenter, the carpenter could, of course, patent the new frame, but he could not oust the employer in his right to continue making the invention, for it would be held that the employer had acquired an implied license. if he could not use it, then he would not be getting the very advantage for which he employed this particular carpenter, and if he did get that right, he would be getting all that he employed the carpenter for, and that right would not be at all lessened by the fact that the carpenter had a patent under which he could license other people. the patent does not constitute the right to make or use or sell, for such right is enjoyed without a patent. the patent constitutes the "exclusive" right to make, sell or use, and this the shop owner does not get unless he specially bargains for it. implied licenses stand on delicate ground, and where men employ people of ingenious talent, with the understanding that the results of such talent developed during the employment shall inure to the benefit of the employer, there is only one safeguard, and that is to found the employment on a contract unmistakably setting forth the understanding. new purpose. if an invention is old, it is old regardless of any new purpose to which it is put. it is no invention to put a machine to a new use. if an inventor contrives a meritorious machine for the production of coins or medals, his invention is lacking in novelty if it should appear that such a machine had before been designed as a soap press, and this fact is not altered by any merely structural or formal difference, such as difference in power or strength, due to the difference in duty. the invention resides in the machine and not in the use of it. if the soap press is covered by an existing patent, that patent is infringed by a machine embodying that invention, regardless of whether the infringing machine be used for pressing soap or silver. and it is no invention to discover some new capacity in an old invention. an inventor is entitled to all the capacities of his invention. combination claims. many people have an erroneous notion regarding patent claims, and consider the expression "combination" as an element of weakness. the fact is, that all mechanical claims that are good for anything are combination claims. no claim for an individual mechanical element has come under my notice for many years and i doubt if a new mechanical element has been lately invented. all claims resolve themselves into combinations, whether so expressed or not. combination does not necessarily imply separateness of elements. the improved carpet tack is after all but a peculiar combination of body and head and barbs. the erroneous public contempt for combination claims is based upon the legal maxim, that if you break the combination you avoid the claim and escape infringement, and this legal maxim should be well understood in formulating the claims. if the claim calls for five elements and the competitor can omit one of the elements, he escapes infringement. therefore, the claim is good only when it recites no elements which are not essential. many inventors labor under the delusion that a claim is strong in proportion to the extent of its array of elements. the exact opposite is the truth, and that claim is the strongest which recites the fewest number of elements. it is the duty of the inventor to analyze his invention and know what is and what is not essential to its realization. it is the duty of the patent solicitor to sift out the essential from the non-essential, and to draft claims covering broad combinations involving only essential elements. sometimes the inventor will help him in this matter, but quite as often he will, through ignorance, hinder him and combat him. the invention having been carefully analyzed and reduced to its prime factors, and the claim having been provided to comprise a combination involving no element which is not essential to a realization of the invention, a new and more important question arises. the elements have been recited in terms fitted to the example of the invention thus far developed. the combination is broadly stated, but the terms of the elements are limiting. cannot some ingenious infringer realize the invention by a similar combination escaping the literalism of the terms of the elements? it is at this stage that the claim must be carefully studied. the inventor, or some one for him, must assume the position of a pirate, and set his wits to work to contrive an organization realizing the invention but escaping the terms of the proposed claim. when such an escaping device is schemed out, then the defect in the claim is developed and the claim must be redrawn. in this way every possible escape must be studied so as to secure to the inventor adequate protection for his invention. solicitors find it difficult to get inventors to do or consider this matter properly, inventors being too often inclined to disparage alternative constructions, the matter being largely one of sentiment founded on the love of offspring. the wise inventor will recognize the fact that the patent which he proposes to get is the deed to valuable property; that the object of the deed is not to permit him to enter upon the property, for he can do that without the deed, but that it is to keep strangers from entering upon the property; that he desires to enjoy his invention without unauthorized competition; that when the property begins to yield profit it will invite competition; that competitors may make machines worse than or as good as or better than his; and that he can get adequate protection only in a claim which would bar poorer as well as better machines embodying his invention. briefly, then, all good claims for mechanism are combination claims; the fewer the elements recited, the stronger will the claim be; non-essential elements weaken or destroy the claim; the claim should not be considered satisfactory so long as a way is seen for the escape of the ingenious pirate. combinations and aggregations. a given association of mechanical elements may be entirely new, but it does not follow that it forms a patentable association, for not all new things are patentable. if the new association is a combination, it is patentable, but if it is a mere aggregation, it is unpatentable. an association may be new and still all of its separate elements may be old, the act of invention lying in the fact that the elements have been so associated with relation to each other as to bring about an improved result, or an improved means for an old result. all new machines are, after all, composed of old elements. the law presupposes that the elements are old, and that the invention resides in the peculiar association of them. if we take a given mechanical element, recognized as having had a certain capacity, and if we then similarly take some other mechanical element and employ it only for its previously recognized capacity, and if we then add the third element for its recognized capacity, we have in the end only an association of three elements each performing its well recognized individual office, and the entire association performing only the sum of the recognized individual elements. such an association is a mere aggregation, a mere adding together of elements, without making the sum of the results any greater in the association than it was in the individual elements. it is simply adding two to one and getting three as a result. an aggregation is unpatentable. as an illustration, a heavy marble statue of jupiter is found in the parlor and difficult to move. ordinary casters are put under its pedestal and it becomes easier to move. modern anti-friction two-wheeled casters are substituted for the commoner casters, and the statue becomes still easier to move. casters were never before associated with a statue of jupiter. here is a new association, but it is a mere aggregation. the statue of jupiter has been unmodified by the presence of the casters, and the casters perform precisely the same under the statue of jupiter that they did under the bedstead. there is no combined result, and there is no patentable combination. but if an inventor takes a given mechanical element for the purpose of its well recognized capacity, and then associates with it another mechanical element for its recognized capacity, but so associates the two elements that one has a modifying effect upon the capacity of the other element, then the association will be capable of a result greater than the sum of the results for the individual elements. this excessive result is not due to the individual elements, but to the combination of them. one has been added to one and a sum greater than two has been secured. the modification of result may be due merely to the bringing of the two elements together, so that they may mutually act upon each other, or it may be due to the manner or means by which they are joined. in a patentable combination the separate elements mutually act upon each other to effect a modification of their previous individual results, and secure a conjoint result greater than the sum of the individual results. the elements of a combination need not act simultaneously; they may act successively, or some may act without motion. as an illustration, assume an old watch in which there was a stem for setting the hands, and assume another old watch with a stem for winding the spring. if an inventor should make a watch, and provide it with the two stems, he would have only an aggregation. but if he employed but one stem, and so located it that it could be used at will for setting the hands or for winding the spring, then he would have produced a combination. the particular instance just given is not a case of the same number of elements, producing a result in excess of the individual results of the separate elements, but is rather a case of a lesser number of elements, producing a combination result equal to the sum of the previous results of a greater number of elements. a better example would perhaps be a new watch with its two old stems so related that either could be used for setting the hands or for winding the spring. genera and species. an inventor, being the first to produce a given organization, and desiring to patent it, may see at once a patentable variation on the device. in other words, he makes two machines patentably different, but both embodying his main invention. he drafts his broad patent claim to cover both machines. in his patent he must illustrate his invention, and he accordingly shows in the drawings the preferred machine. the two machines represent two species of his generic invention, and for illustration he selects the preferable species. he drafts his generic claim to cover both species, and he follows this with a specific claim relating to the selected species. the question might be asked, if the broad generic claim covers the selected and all other species, why bother with the specific claim, why not rest on the generic claim? the answer is that it might in the future develop that the genus was old, and that the generic claim was invalid, while the specific claim would still be good. the infringer of the specific claim may thus be held notwithstanding the generic claim becomes void. but the inventor cannot claim his second species in his patent. he can claim the genus, and he can claim one species under that genus, but all other species must be covered in separate patents. it is even unwise to illustrate alternative species in a patent for, in case, of litigation, some one of the alternative species might prove to be old. this would have the effect, of course, to destroy the generic claim, but it might possibly have the effect of damaging the specific claim if it should appear that the specific claim was after all merely for a modification as distinguished from a distinct species. were it not for the danger of broad generic claims being rendered void by discovered anticipations, there would be no need for claiming species, but in view of such possibility it is important to claim one species in the generic patent, and to protect alternative species by other patents. combination and sub-combination. a given machine capable of a given ultimate result having been invented, a claim may be drawn to cover the combination of elements comprised in the machine. such claim will cover the machine as a whole. but, the fact being recognized that many machines are, after all, composed of a series of sub-machines, and that these sub-machines, in turn, are composed of certain combinations of elements, and that within these sub-machines there are still minor combinations of elements capable of producing useful mechanical results, and that the sub-machines, or some of the subordinate combinations of elements within the sub-machines, might be capable of utilization in other situations than that comprehended by the main machine, it becomes important that the inventor be protected regarding the sub-machines and the minor useful combinations. claims may be drawn for the combination constituting the main machine, other claims may be drawn for the combinations constituting the operative sub-machines, and claims may be drawn covering the minor useful combinations of elements found within the sub-machines. each claimed combination must be operative. but secondary claims cannot be made for sub-machines or sub-combinations which are for divisional matter or matter which should be made the subject of separate patents. mechanical equivalents. where an inventor produces a new mechanical device for the production of a certain result, he can often see in advance that various modifications of it can be made to bring about the same result, and even if he does not see it he may in the future find competitors getting at the result by a different construction. he analyzes the competing structure, and determines that "it is the same thing only different," and wonders what the legal doctrine of mechanical equivalents means, and asks if he is not entitled to the benefits of that doctrine, so that his patent may dominate the competing machine. an inventor may or may not be entitled to invoke the doctrine of mechanical equivalents, and the doctrine may or may not cause his patent to cover a given fancied infringement. if an inventor is a pioneer in a certain field, and is the first to produce an organization of mechanism by means of which a given result is produced, he is entitled to a claim whose breadth of language is commensurate with the improvement he has wrought in the art. he cannot claim functions or performance, but must limit his claim to mechanism, in other words, to the combination of elements which produces the new result. his claim recites those elements by name. if the new result cannot be produced by any other combination of elements, then, of course, no question will arise regarding infringement. but it may be that a competitor contrives a device having some of the elements of the combination as called for by the claim, the remaining elements being omitted and substitutes provided. the competing device will thus not respond to the language of the claim. but the courts will deal liberally with the claim of the meritorious pioneer inventor, and will apply to it the doctrine of mechanical equivalents, and will hold the claim to be infringed by a combination containing all of the elements recited in the claim, or containing some of them, and mechanical equivalents for the rest of them. were it not for this liberal doctrine, the pioneer inventor could gather little fruit from his patent, for the patent could be avoided, perhaps, by the mere substitution of a wedge for the screw or lever called for by the claim. the court, having ascertained from the prior art that the inventor is entitled to invoke the doctrine of equivalents, will proceed to ascertain if the substituted elements are real equivalents. a given omitted element will be considered in connection with its substitute element, and if the substitute element is found to be an element acting in substantially the same manner for the production of substantially the same individual result, and if it be found that the prior art has recognized the equivalency of the two individual elements, then the court will say that the substituted element is a mechanical equivalent of the omitted element, and that the two combinations are substantially the same. this reasoning must be applied to each of the omitted elements for which substitutes have been furnished. in this way justice can be done to the pioneer inventor. but the courts, in exercising liberality, cannot do violence to the language of the claim. the infringer will not escape by merely substituting equivalents for recited elements, but he will escape if he omits a recited element and supplies no substitute, for the courts will not read out of a claim an element which the patentee has deliberately put into the claim, and a combination of a less number of elements than that recited in the claim is not the combination called for by the claim. it is seldom that the exemplifying device of the pioneer inventor is a perfect one. later developments and improvements by the original patentee, or by others, must be depended on to bring about perfection of structure. those who improve the structure are as much entitled to patents upon their specific improvements in the device as was the original inventor entitled to his patent for the fundamental device. these improvers are secondary inventors, and are not entitled to invoke the doctrine of mechanical equivalents. the secondary inventor did not bring about a new result, but his patent was for new means for producing the old result. his patent is for this improvement in means, and his claim will be closely scrutinized in court, and he will be held to it, subject only to formal variations in structure. the justice of thus restricting the claim of the secondary inventor must be obvious, in view of the fact that if the doctrine of mechanical equivalents were applied to his claim, then the fundamental device on which he improved would probably infringe upon it, which would be an absurdity. it is thus seen that the pioneer inventor may have a claim so broad in its terms that its terms cannot be escaped; that he may invoke the doctrine of equivalents and have his claim dominate structures not directly responding to the terms of the claim; that the secondary inventor, who improves only the means, is limited to the recited means and cannot invoke the doctrine of equivalents. but within this general view, sight is not to be lost of the fact that secondary inventors may be pioneers within certain limits. they are not the first to produce the broad ultimate result, but they may be pioneers in radically improving interior or sub-results, and they may thus reasonably ask for the application of the doctrine of equivalents to their claims within proper limits. the matter often becomes quite complicated, for it is sometimes difficult to determine as to what is the result in a given machine, for many machines consist, after all, of a combination of subordinate machines. thus the modern grain-harvesting machine embodies a machine for moving to the place of attack, a machine for cutting the grain, a machine for supporting the grain at the instant of cutting, a machine for receiving the cut grain, a machine for conveying the cut grain to a bindery, a machine for measuring the cut grain into gavels, a machine for compressing the gavel, a machine for applying the band, a machine for tying the band, a machine for discharging the bundle, a machine to receive the bundles and carry them to a place of deposit, and a machine to deposit the accumulated bundles. the machine would be useful with one or more of these sub-machines omitted, and each machine may be capable of performing its own individual results alone or in other associations. pioneership of invention might apply to the main machine, or to the sub-machines, or even to the sub-organization within the sub-machines. (to be continued.) * * * * * [continued from supplement, no. , page .] the development of the central station. by samuel insull.[ ] [footnote : before the electrical engineering department of purdue university, lafayette, ind., may , .] the success of the low-tension system was followed by the introduction of the alternating system, using high potential primaries with the converters at each house, reducing, as a rule, from , down to either or volts. i am not familiar with the early alternating work, and had not at my disposal sufficient time in preparing my notes to go at any length into an investigation of this branch of the subject; nor do i think that any particular advantage could have been served by my doing so, as it has become generally recognized that the early alternating work with a house-to-house converter system, while it undoubtedly helped central station development at the time, proved very uneconomical in operation and expensive in investment, when the cost of converters is added to the cost of distribution. the large alternating stations in this country have so clearly demonstrated this that their responsible managers have, within the last few years, done everything possible, by the adoption of block converters and three-wire secondary circuits, to bring their system as close as they could in practice to the low-tension direct-current distribution system. i do not want to be understood as undervaluing the position of the alternating current in central station work. it has its place, but to my mind its position is a false one when it is used for house-to-house distribution with converters for each customer. the success of the oldest stations in this country, and the demonstration of the possibilities of covering areas of several miles in extent by the use of the three wire system, resulted in much capital going into the business. one of the earliest stations of a really modern type installed on either side of the atlantic was built by the berlin electricity works. the engineers of that station, while recognizing the high value of the distributing system, went back to edison's original scheme of a compact direct-connected steam and electric generator, but with dynamos of the multipolar type designed and built by siemens & halske, of berlin, the engines being of vertical marine type. this was followed by the projecting in new york of the present duane street station, employing boilers of pounds pressure, triple and quadruple expansion engines of the marine type, and direct-connected multipolar dynamos. almost immediately thereafter, the station in atlantic avenue, boston, somewhat on the same general design so far as contents is concerned, was erected. in a small station, but on the same lines, was projected for san francisco, and in the present harrison street station of the chicago edison company was designed, and, benefiting by the experience of berlin, new york and boston, this station produces electric current for lighting purposes probably cheaper than any station of a similar size anywhere in this country. it is not necessary for me to go into detail in explanation of the modern central station. you are all doubtless quite familiar with the general design, but if you will examine the detail drawings of the harrison street station, which i have brought with me, you will find that every effort has been made to provide for the economical production of steam, low cost of operating, good facilities for repairs and consequently low cost, and for permanency of service. you have but to go into any of the modern central stations in midwinter, to see them turning out anywhere from , to , amperes with a minimum of labor, to appreciate the fact that central station business is of a permanent and lucrative character. to go back to the question of alternating currents, the work done in connection with the two-phase and three-phase currents and the perfection of the rotary transformer has resulted in introducing into central station practice a further means of economizing the cost of production--by concentration of power. according to present experience, it is (except in some extraordinary cases) uneconomical to distribute direct low-tension current over more than a radius of a mile and a half from the generating point. the possibility of transmitting it at a very high voltage, and consequently low investment in conductors, has resulted in the adoption of a scheme, in many of the large cities, of alternating transmission combined with low tension distribution. the limit to which this alternating transmission can be economically carried has not yet been definitely settled, but it is quite possible even now to transmit economically from the center of any of our large cities to the distant suburbs, by means of high potential alternating currents, distributing the current from the subcenter distribution by means either of the alternating current itself and large transformers for a block or district or else, if the territory is thickly settled, by means of a system of low-tension mains and feeders, the direct current for this purpose being obtained through the agency of rotary transformers. there are various methods of producing the alternating current for transmission purposes. in some cases the generators are themselves wound for high potential; in others they are wound for volts, and step-up transformers are used, carrying the current up to whatever pressure is desired, from , to , volts. in other cases dynamos are used having collector rings for alternating current on one side and a commutator for direct current on the other side of the armature, thus enabling you, when the peak in two districts of a city comes at two different times, to take care of this peak by means of the same original generating unit, furnishing direct low-tension current to the points near the central station and alternating current to the distant points. in other cases, where a small amount of alternating current is required on the transmission line, it has even been found economical to take direct current from a large unit, change it by means of a rotary transformer into alternating current, step up from to, say, , volts, go to the distant point, and step down again to volts alternating, and then convert again by means of a rotary transformer into low-potential direct current. the introduction of alternating current for transmission purposes in large cities is probably best exemplified in the station recently erected in brooklyn, where alternating current is produced and carried to distant points, and then used to operate series arc-light machines run by synchronous motors, the low-tension direct-current network being fed by rotary transformers, and alternating circuits arranged with block converters, and even in some cases separate converters for each individual customer in the scattered districts. it would be very interesting to go at length into the details of cost in this, the latest development of central station transmission, but time will not permit; nor have i the time at my disposal to go at length into the central station business as developed by the electric street railways now so universally in use, or another phase of the business as exemplified by the large transmission plants, the two greatest examples of which, in this country, are probably those at niagara falls, n.y., and lachine rapids, near montreal. so far as street railways and power transmission are concerned, i would draw your attention to the fact that the same underlying principle of multiple-arc mains and feeders originally conceived by mr. edison is as much a necessity in their operation as it is in the electric lighting systems, whether those systems be operated on the old two-wire plan, the three-wire plan or by means of alternating currents. passing from a review of central station plants and distribution system naturally bring us to the operating cost and the factors governing profit and loss of the enterprise. in considering this branch of the subject, i will confine my remarks to the business as operated in chicago by the company with which i am connected. our actual maximum last winter came on december , our load being approximately , horse power. a comparison of the figures of maximum capacity and maximum load of last winter shows that we had a margin in capacity over output of about per cent. the load curves shown this evening represent the maximum output of last winter (december ), an average summer load last year (june ), and an average spring load of this year (may ). for our purposes we will assume the maximum capacity of the plant and the maximum load of the system to be identical. the maximum load last winter occurred, as i have stated, on december , about : o'clock in the afternoon, and lasted less than half an hour. it should be borne in mind that the period of maximum load only lasts for from two to three months, and that the investment necessary to take care of that maximum load, has to be carried the whole year. it should not be assumed from this statement that the whole plant as an earning factor is in use per cent. of the year. the fact is that, during the period of maximum load, the total plant is in operation only about hours out of the , hours of the year; so that you are compelled, in order to get interest on your investment, to earn the interest for the whole of the year in about ½ per cent. of that period, on about per cent. of your plant. this statement must bring home to you a realization of the fact that by far the most serious problem of central station management, and by far the greatest item of cost of your product, is interest on the investment. it may be that the use of storage batteries in connection with large installations will modify this interest charge, but even allowing the highest efficiency and the lowest cost of maintenance ever claimed for a storage battery installation, the fact of high interest cost must continue to be the most important factor in calculating profit and loss. this brings home to us the fact that in his efforts to show the greatest possible efficiency of his plant and distribution system, it is quite possible that the station manager may spend so much capital as to eat up many times over in interest charge the saving that he makes in direct operating expenses. it is a common mistake for the so-called expert to demonstrate to you that he has designed for you a plant of the highest possible efficiency, and at the same time for him to lose sight of the fact that he has saddled you with the highest possible amount of interest on account of excessive investment. operating cost and interest cost should never be separated. one is as much a part of the cost of your current as the other. this is particularly illustrated in connection with the use of storage batteries. those opposed to their use will point out to you that of the energy going into the storage battery only per cent. is available for use on your distribution system. that statement in itself is correct; but in figuring the cost of energy for a class of business for which the storage battery is particularly adapted, the maximum load, that portion of your operating cost affected by the per cent. loss of energy in the battery, forms under ½ per cent. of your total cost, and it must be self-evident, in that case at least, that the per cent. loss in the storage battery is hardly an appreciable factor in figuring the operating cost of your product. so far as i have been able to ascertain, it would appear to be economical to use storage batteries in connection with central station systems the peak of whose load does not exceed from two to two and one-half hours. in order to illustrate the important bearing which interest has on cost, i have prepared graphical representations of the cost of current, including interest, under conditions of varying load factors. for the purpose of this chart i have assumed an average cost of current, so far as operating and repairs and renewals and general expense are concerned, extending over a period of a year, although of course these items are more or less attested by the character of the load factor. for the purpose of figuring interest, i have selected seven different classes of business commonly taken by electric light and power companies in any large city. take, for instance, an office building. it has a load factor of about . per cent., that is, the average load for the whole year is . per cent. of the maximum demand on you for current at any one time during that period; or, to put it in another way, this load factor of . per cent. would show that your investment is in use the equivalent of a little over hours a year on this class of business. this is by no means an extreme case. you can find in almost every large city customers whose load factors are not nearly as favorable to the operating company, their use of your investment being as low as the equivalent of or hours a year. take another class of business, that of the haberdasher, or small fancy goods store. as a rule these stores are comparatively small, with facilities for getting a large amount of natural light and little use for artificial light. the load factor as shown by the chart is about per cent., the use of your investment being not quite twice as long as that of the office building. day saloons show an average of per cent. load factor; cafetiers and small lunch counters about per cent., while the large dry goods stores, in which there is comparatively little light, have a load factor of per cent. and use your investment seven times as long per year as the office building. power business naturally shows a still better load factor, say per cent., and the all-night restaurant has a load factor of per cent. you will see from this that the great desideratum of the central station system is, from the investors' point of view, the necessity of getting customers for your product whose business is of such a character as to call for a low maximum and long average use. this question of load factor is by all means the most important one in central station economy. if your maximum is very high and your average consumption very low, heavy interest charges will necessarily follow. the nearer you can bring your average to your maximum load, the closer you approximate to the most economical conditions of production, and the lower you can afford to sell your current. take, for instance, the summer and winter curves of the chicago edison company. the curve of december , , shows a load factor of about per cent.; the curve of may , , shows a load factor of nearly per cent. now, if we were able in chicago to get business of such a character as would give us a curve of the same characteristics in december as the curve we get in may; or, in other words, if we could improve our load factor, our interest cost would be reduced, an effect would be produced upon the other items going to make up the cost of current, and we probably could make more money out of our customers at a lower price per unit than we get from them now. many schemes are employed for improving the load factor, or, in other words, to encourage a long use of central station product. some companies adopt a plan of allowing certain stated discounts, provided the income per month of each lamp connected exceeds a given sum. the objection to this is that it limits the number of lamps connected. other companies have what is known as the two-rate scheme, charging one rate for electricity used during certain hours of the day and a lower rate for electricity used during the balance of the day, using a meter with two dials for this purpose. other companies use an instrument which registers the maximum demand for the month, and the excess over the equivalent of a certain specified number of hours monthly in use of the maximum demand is sold at greatly reduced price. the last scheme would seem particularly equitable, as it results in what is practically an automatic scale of discounts based on the average load factor of the customers. it does not seem to be just that a man who only uses your investment say hours a year should be able to buy your product at precisely the same price as the man who uses your investment say , hours a year, when the amount of money invested to take care of either customer is precisely the same. surely the customer who uses the product on an average times longer than the customer using it for only hours is entitled to a much lower unit rate, in view of the fact that the expense for interest to the company is in one case but a fraction per unit of output of what it is in the other. this fact is illustrated by the interest columns on the graphic chart already referred to. supposing that the central station manager desired to sell his product at cost, that is, an amount sufficient to cover his operating, repairs and renewals, general expense, and interest and depreciation, he would have to obtain from the customer having the poorest load factor, as shown on the load chart, over four times as much per unit of electricity as it would be necessary for him to collect from the customer having the largest load factor. no one would think of going to a bank to borrow money and expect to pay precisely the same total interest whether he required the money for one month or for twelve; and for the same reason it seems an absurdity to sell electricity to the customer who uses it but a comparatively few hours a year at the same price at which you would sell it to the customer using it ten hours a day and three hundred days a year, when it is remembered that interest is the largest factor in cost, and the total amount of interest is the same with the customer using it but a few hours a year as it is with the customer using it practically all the year around. i have dwelt thus at length on the question of interest cost in operating a central station system, not alone for the purpose of pointing out to you its importance in connection with an electrical distribution system, but also to impress upon you its importance as a factor in cost; in fact, the most important factor in cost in any public service business which you may enter after leaving this institution. most of the businesses presenting the greatest possibilities from the point of view of an engineering career are those requiring very large investment and having a comparatively small turnover or yearly income. of necessity, in all enterprises of this character, the main factor of cost is interest, and if you intend following engineering as a profession, my advice to you would be to learn first the value of money, or, to put it another way, to learn the cost of money. before leaving this question of interest and its effect upon cost, i would draw your attention to the fact that while interest is by far the most important factor of cost, it is a constantly reducing amount per unit of maximum output in practically every central station system. when a system is first installed, it is the rule to make large enough investment in real estate and buildings to take care of many times the output obtained in the first year or so of operation. as a rule, the generating plant from the boilers to the switchboard is designed with only sufficient surplus to last a year or so. in the case of the distributing system the same course is followed as in the case of real estate and buildings, with a view to minimizing the ultimate investment. mains are laid along each block facing, feeders are put in having a capacity far beyond the necessity of the moment; consequently interest cost is very high when a plant first starts, except, as i have stated, in the case of the machinery forming the generating plant itself. as the business increases from, year to year, the item of interest per unit of maximum output consequently will constantly decrease, owing to the fact that each additional unit of output following an increase of connected load increases the divisor by which the total interest is divided. the result is from year to year the interest cost of each additional unit of maximum output is a constantly reducing amount, and consequently the average interest cost of each unit of maximum output should, in a well regulated plant, grow less from year to year until the minimum interest cost per unit is reached. this minimum interest cost is reached when the capacity of the whole system and the total units of output at maximum load are identical, although of course it will always be necessary to have a certain margin of capacity over possible output, as a factor of safety. this same rule, although to a less extent, applies to the operating and general expense cost, that is, the cost other than interest. to particularize, the manager's salary and other administrative expenses do not increase in proportion to maximum output of station; therefore, the cost of administration per unit of output, if the business is in a healthy condition, must be from year to year reduced. there are a great many other expenses that are not directly in proportion to output, and these follow the same rule. in a well-run plant the percentage of operating expenses to gross receipts will stand even year after year, while the income per unit of output will be constantly reduced. this is an excellent evidence of the fact that the cost per unit of output is constantly being reduced, as, if it were not, the percentage of expenses to gross receipts would be increased in direct proportion to the reduction in price. moreover, it should be borne in mind that there are many difficulties in the way of universal use of electric energy from a central station system. it is the rare exception to find a house not piped for gas and water. in the case of the latter it is almost invariably the rule that owners are compelled to pipe for water, under the sanitary code of the municipality. on the other hand, in a large residential district, it is the exception to find a house wired for electric light; consequently the output of current per foot of conductor is at the present time very low as compared with the output of gas per foot of gas pipe in any of the large cities. the expense of wiring (which must of necessity be borne by the householder) is large, and it is often a barrier to the adoption of electric illumination, but as the rule to wire houses becomes more general, the output per foot of main will constantly increase, and therefore the interest per unit of output per foot of main will constantly decrease. this same rule will apply in the case of expenses of taking care of and repairing the distribution system, although to not so great an extent. if you will take into account these various factors constantly operating toward a reduction of operating and general expense cost, and interest cost, the conclusion must necessarily be forced upon you that the price at which current can be sold at a profit to-day is in no sense a measure of the income per unit which it will be necessary for central station managers to obtain in the future. in - it was difficult to make both ends meet with an income of cents per kilowatt hour, to-day there are many stations showing a substantial return on their investment whose average income does not exceed cents per kilowatt hour, showing per cent. reduction in price in less than two decades. how far this constant reduction in cost, followed by a constant reduction in selling price, will go, it is difficult to determine; but if so much has been accomplished during the first years of the existence of the industry, is it too much to predict that in a far less time than the succeeding years electric current for all purposes will be within the reach of the smallest householder and the poorest citizen? but few industries can parallel the record already obtained. if you will trace the history of the introduction of gas as an illuminant, you will find that it took a much longer time to establish it on a commercial basis than it has taken to establish most firmly the electric lighting industry. all the great improvements in gas, the introduction of water gas, the economizing in consumption by the use of the welsbach burner, have all been made within the time of those before me, and yet, notwithstanding that when these gas improvements started, the electric lighting business was hardly conceived, and certainly had not advanced to a point where you could claim that it had passed the experimental stage--notwithstanding this, the cost of electrical energy has decreased so rapidly that to-day there are many large central station plants making handsome returns on their investments at a far lower average income per unit of light than the income obtained by the gas company in the same community. in making my calculations which have led me to this conclusion, i have assumed that , watts are equal to , feet of gas. this comparison holds good, provided an incandescent lamp of high economy is used as against the ordinary gas burner. to make a comparison between electric illumination and incandescent gas burners, such as the welsbach burner, you must figure on the use of an arc lamp in the electric circuit instead of an incandescent lamp, which is certainly fair when it is remembered that incandescent gas burners are, as a rule, used in places where arc lamps should be used if electric illumination is employed. with such brilliant results obtained in the past, the prospects of the central station industry are certainly most dazzling. while the growth of the business has been phenomenal, more especially since , i think it can be conservatively stated that we have scarcely entered upon the threshold of the development which may be expected in the future. in very few cities in the united states can you find that electric illumination exceeds more than per cent. of the total artificial illumination for which the citizens pay. if this be the state of affairs in connection with the use of electricity for illuminating purposes, and if you will bear in mind the many other purposes to which electricity can be adapted throughout a city and supplied to customers in small quantities, you may get some faint conception of the possible consumption of electrical energy in the not far distant future. methods of producing it may change, but these methods cannot possibly go into use unless their adoption is justified by saving in the cost of production--a saving which must be sufficient to show a profit above the interest and depreciation on the new plant employed. it is within the realms of possibility that the present form of generating station may be entirely dispensed with. it has already been demonstrated experimentally that electrical energy may be produced direct from the coal itself without the intervention of the boiler, engine and dynamo machine. whether this can be done commercially remains to be proved. whatever changes may take place in generating methods, i should, were i not engaged in a business which affords so many remarkable surprises, be inclined to question the possibility of any further material change in the distributing system. improvements in the translating devices, such as lamps, may add enormously to the capacity of the distributing system per unit of light; but it does seem to me that the system itself, as originally conceived, is to a large extent a permanency. should any great improvements take place in the medium employed for turning electrical energy into light, the possible effect on cost, and consequently selling price, would be enormous. * * * * * the proposal of gov. black, which has now become law, to depute to cornell the care of a considerable tract of forest land, and the duty of demonstrating to americans the theory, methods and profits of scientific forestry, has a curious appropriateness much commented on at the university, since two-thirds of the wealth of cornell has been derived from the location and skillful management of forest lands, the net receipts from this source being to date $ , , . in the course of twenty years management the university has thrice sold the timber on some pieces of land which it still holds, and received a larger price at the third sale than at the first. the conduct of this land business is so systematized that the treasurer of the university knows to a dot the amount of pine, hemlock, birch, maple, basswood and oak timber, even to the number of potential railroad ties, telegraph poles and fence posts on each fourth part of a quarter section owned by cornell. certainly, cornell is rich in experience for the business side of a forestry experiment such as gov. black proposes. the university forest lands from which its endowment has been realized are in wisconsin. * * * * * books may be called heavy when the qualifying term is not applied to their writers, but to the paper makers. it is falsifications in the paper that give it weight. sulphate of baryta, the well known adulterate of white lead, does the work. a correspondent, writing to the london saturday review, gives the weight of certain books as: miss kingsley's "travels in africa." pounds ounces; "tragedy of the cæsars," pounds; mahan's "nelson" ( vol.), pounds ounces; "tennyson" ( vol.), pounds ounces; "life and letters of jowett" ( vol.), pounds ounce. to handle these dumb-bell books, the saturday review advises that readers take lessons in athletics. * * * * * the lock of the dortmund-ems canal at henrichenburg. the dortmund-ems canal, destined to connect the heart of german industry with the sea, was formally dedicated on april , and partially opened to commerce. after its completion, german coal will be transported to the harbors of the ems at the same cost as the english coal which has hitherto forced back the treasures of our soil; our black diamonds will then be sold in the markets of the world, and the kaiser wilhelm canal will enable the western part of the empire to exchange its coal and iron for the grain and wood of the east. many difficulties were encountered in cutting the canal, owing partly to the vast network of railroads in the coal region of westphalia, but chiefly due to the insufficiency of moisture in the highlands, the latter not containing enough water to supply the many necessary sluices, at which it could be easily foreseen considerable traffic would occur. [illustration: the lock of the dortmund-ems canal at henrichenburg.] for the modern engineer there are, however, no insurmountable obstacles. instead of a line of ordinary locks, a single structure was erected sufficient for the needs of the entire region. this lock is situated at henrichenburg, near dortmund, and our illustration pictures it with its lock-chamber half raised. the lock, which serves to overcome a difference in level of fifty-nine feet, raises vessels of , tons capacity with a velocity of . to . foot per second, and has been constructed after a new and astonishingly simple system. the lock chamber, designed for the reception of the various vessels, is . feet in length and . feet in breadth and normally contains . feet of water. under the sluice in a line with the long axis are five wells filled with water in which cylindrical floats are placed, connected to the bottom of the chamber by means of iron trellis-work. the floats are placed so deeply that, in their highest position, their upper edges are always submerged; they are, moreover, of such size that by means of their upward impulsion the chamber is held in equilibrium. irrespective of the small differences of pressure which arise from the varying immersion of the framework, the lock will in all positions be in equilibrium. since a vessel which enters the lock displaces a volume of water whose weight is equal to the weight of the vessel, a constant equilibrium will always be maintained and only a minimum force required to raise or lower the chamber. in order to move the lock-chamber up and down and to sustain it constantly in a horizontal position, nuts have been fixed to strong crossbeams, through which powerful screw-rods work. these rods are held in place by a massive framework of iron and are turned to the left or to the right by means of a small steam engine, placed at one side of the lock, which engine, by means of a longitudinal shaft, drives two cross shafts to which bevel wheels are attached. by this means the chamber is lowered and raised. the screw rods are so powerful that they sustain the entire weight of the lock chamber, and the pitch of the thread is such that spontaneous sliding or slipping is impossible, the chamber being, therefore, kept constantly in the desired position. it is interesting to note that the hollow space in the screw rods is heated by steam during winter, thus preventing the formation of ice in the machinery. during the eighties, locks for ships of tons capacity were erected in england and france, at anderton, les fontinettes and la louvière. the lock at henrichenburg, however, exceeds all its predecessors, not only in size, but also in security. at all events, the structure is a worthy memorial of the energy and genius of german engineers.--illustrirte zeitung. * * * * * paper hanging by machine is the latest achievement, according to a german contemporary, says the engineer. the arrangement used for this purpose is provided with a rod upon which the roll of paper is placed. a paste receptacle with a brushing arrangement is attached in such a manner that the paste is applied automatically on the back of the paper. the end of the wall paper is fixed at the bottom of the wall and the implement rises on the wall and only needs to be set by one workman. while the wall paper unrolls and, provided with paste, is held against the wall, an elastic roller follows on the outside, which presses it firmly to the wall. when the wall paper has reached the top, the workman pulls a cord, whereby it is cut off from the remainder on the roll. * * * * * the american "regular." by the english correspondent of the london times on board the united states transport "gussie." the "regular" of the united states is in many respects the least equipped foot soldier of my acquaintance. this was my reflection as i overhauled the kit of a private this morning on board the "gussie." there was not a single brush in his knapsack. i counted three in that of a spanish foot soldier only a few weeks ago. the american knapsack is merely a canvas bag cut to the outward proportions of the european knapsack, but in practical features bearing affinity with the "rückensack" of the tyrolean chamois hunters, or pack-sack of the backwoodsmen of canada and the adirondack mountains. this knapsack of the american is not intended to be carried on any extended marches, although the total weight he is ever called upon to carry, including everything, is only pounds, a good pounds less than what is carried by the private of germany. the men of this regiment, in heavy marching order, carry an overcoat with a cape, a blanket, the half of a shelter tent, and one wooden tent pole in two sections. the rifle could be used as a tent pole--so say men i talk with on the subject. on this expedition overcoats are a superfluity, and it is absurd that troops should be sent to the tropics in summer wearing exactly the same uniform they would be using throughout the winter on the frontiers of canada. this war will, no doubt, produce a change after english models. at present the situation here is prevented from being painful because no marching has yet been attempted, and the commanding officers permit the most generous construction in the definition of what is a suitable uniform. on the trip of this ship to cuba, no officer or man has ever worn a tunic excepting at guard mounting inspection. the men who went ashore near cabañas on may and pitched into some spaniards left their coats behind and fought in their blue flannel shirts. of the officers, some wore a sword, some did not, though all carried a revolver. no orders were issued on the subject--it was left to individual taste, i have experienced hotter days at german maneuvers than on the coast of cuba during the days we happened to be there, yet i have never noticed any disposition in the army of william ii. to relax the severity of service even temporarily. my german friends sincerely believe that the black stock and the hot tunic are what has made prussia a strong nation, and to disturb that superstition would be a thankless task. in the way of clothing the american private carries a complete change of under-drawers, under-shirt, socks, laced boots and uniform trousers. my particular private was carrying a double allowance of socks, handkerchiefs, and underwear. he had a toothbrush and comb. that is the heavy marching order knapsack. for light marching, which is the usual manner, the man begins by spreading on the ground his half-tent, which is about the size of a traveling rug. on this he spreads his blanket, rolls it up tightly into a long narrow sausage, having first distributed along its length a pair of socks, a change of underwear, and the two sticks of his one tent pole. then he brings the ends of this canvas roll together, not closely, as in the german army, but more like the ends of a horse-shoe, held by a rope which at the same time stops the ends of the roll tightly. when this horse shoe is slung over the man's shoulder, it does not press uncomfortably upon his chest. the total weight is distributed in the most convenient manner for marching. the packing of the man's things is strictly according to regulation, excepting only the single pocket in his knapsack, where he may carry what he chooses, as he chooses. his light canvas haversack is much like the english one, and his round, rather flat water flask is covered with canvas. it is made of tin, and the one i inspected was rusty inside. it would be better if of aluminum. in the haversack is a pannikin with a hinged handle that may be used as a saucepan. over this fits a tin plate, and when the two are covering one another the handle of the pannikin fits over both by way of handle. it is an excellent arrangement, but should be of aluminum instead of a metal liable to rust. the most valuable part of this haversack is a big tin cup that can be used for a great variety of purposes, including cooking coffee. it is hung loose at the strap of the haversack. of course each man has knife, fork and spoon, each in a leather case. the cartridge belt contains rounds, which are distributed all the way around the waist, there being a double row of them. the belt is remarkably light, being woven all in one operation. it is of cotton and partly some material which prevents shrinking or loosening. the belts have stood admirably the test put upon them for the last six days, when it has rained every day, on top of the ordinary heavy moisture usual at sea in the tropics. the test is the more interesting from their having been previously in a very dry country. officers and men alike unite in praise of this cartridge belt. the particular private whom i was inspecting said he now carried as easily as he formerly carried . this belt rests loosely on the hips, without any straps over the shoulders. it is eminently businesslike in appearance. the hat is the gray felt of south africa, australia, and every other part of the world where comfort and cost are consulted. no boots are blacked on expeditions of this kind. the men who form in line for guard duty have their tunics well brushed, but that may be due to extraneous assistance. for fighting purposes, then, the united states private has nothing to keep clean excepting his rifle and bayonet. he carries no contrivances for polishing buttons, boots, or the dozen of bits of accouterment deemed essential to a good soldier in europe. in spain, for instance, the private, though he may have nothing in his haversack, will, nevertheless, carry a clumsy outfit of tools for making his uniform look imposing. now, as to discipline in the american army i cannot speak at present, for the war is yet too young. it may, however, be worth noting that in this particular regiment, while most complete liberty was allowed the men all the twelve days of the rail journey from san francisco to tampa, not a single case of drunkenness or any other breach of discipline was reported. among the men on this boat there has not in the past seven days been a single case of sickness of any kind or any occasion for punishing. the firing discipline during the three times we have been under fire has been excellent; the obedience of soldiers to their officers has been as prompt and intelligent as anything i have seen in europe; and as to coolness under fire and accuracy of aim, what i have seen is most satisfactory. the men evidently regard their officers as soldiers of equal courage and superior technical knowledge. to the yankee private "west pointer" means what to the soldier of prussia is conveyed by noble rank. in my intimate intercourse with officers and men aboard this ship i cannot recall an instance of an officer addressing a private otherwise than is usual when a gentleman issues an order. i have never heard an officer or noncommissioned officer curse a man. during the engagement of cabañas the orders were issued as quietly as at any other time, and the men went about their work as steadily as bluejackets on a man-o'-war. all this i note, because this is the first occasion that united states troops have been in action since the civil war, and because i have more than once heard european officers question the possibility of making an army out of elements different from those to which they were accustomed. i have heard germans insist that unless the officer appears in uniform he cannot command the respect of his men. on this ship it would be frequently difficult to tell officers from men when the tunic is laid aside and shoulder straps are not seen. there are numberless points of resemblance between tommy atkins and the yankee private; and the sandhurst man has no difficulty in understanding the west pointer. but to do this we must go a little beneath the surface and see things, not on the parade ground, but in actual war. for dress occasions the american uniform is far and away the ugliest and most useless of all the uniforms i know. the helmets and cocked hats are of the pattern affected by theatrical managers, the decorations tawdry, the swords absurd, the whole appearance indicative of a taste unmilitary and inartistic. the parade uniform has been designed by a lot of unsoldierly politicians and tailors about washington. their notion of military glory is confused with memories of st. patrick's day processions and masonic installations. they have made the patient united states army a victim of their vulgar designs, and to-day at every european army maneuver one can pick out the american military attache by merely pointing to the most unsoldierly uniform on the field. on the battlefield, however, there are no political tailors, and the washington dress regulations are ruthlessly disregarded. * * * * * steering gear of north german lloyd steamers "coblentz," "mainz," and "trier." the steering gear illustrated below, which has been fitted to a number of vessels in this country as well as on the three north german lloyd steamers above named, is designed, primarily, to effect the distribution of the leverage more in proportion to the resistance of the rudder than exists in ordinary gears. the latter, as a rule, exert a uniform and decreasing, instead of an increasing, purchase on the rudder, in moving it from midgear to hard over. this important object is attained in the gear under notice chiefly through the arrangement of the quadrant and the spring buffers, which form an essential part of it, and of the tiller crosshead. the quadrant--which, as may be gathered from our illustration, has its main body formed of wrought steel, flanged and riveted, making an exceptionally strong design--works on its own center. it travels through degrees in moving the tiller crosshead through degrees, and in doing so increases the leverage over the rudder to an extent which is equivalent to a gain of per cent. upon midgear position. [illustration: hand gear hard over.] [illustration: hand gear amidships. croom & arthur's steering gear.] being carried on its own center, and not, as is usual, on the rudder stock, and with its rim supported on rollers, the quadrant does not impose upon the rudder pintles any of its own weight, thus diminishing the wear on these parts. this arrangement also keeps the quadrant always in good gear with its pinion, thereby allowing the teeth of both to be strengthened by shrouding, and rendering them exempt from the effects of sinking and slogger of the rudder stock as the pintles wear. the rack and pinions are of cast steel, as is also the tiller crosshead. the spring buffers, which, as has been said, form an essential part of the quadrant, are fitted with steel rollers at the point of contact with the crosshead, thereby reducing the friction to a minimum. the springs, by their compression, absorb any shock coming on the rudder, and greatly reduce the vibration when struck by a sea. they are made adjustable, and can be either steel or rubber. our illustrations show the arrangement of the gear as worked by hand at the rudder head, but of course gears are made having a steam steering engine as the major portion of the arrangement--the two cylinders being placed directly over the quadrant--thus securing the well known advantages attaching to a direct rudder head steering engine as compared with the engine situated amidship, with all the friction of parts, liability to breakage, etc., thereby entailed. whether with engine amidship or directly over the rudderhead, ample provision is made for putting the hand power into gear by means of a friction clutch within the standard upon which the hand wheels are mounted. the clutch is of large diameter and lined with hard wood, power and ready facility being provided by the hand lever--seen at the top of standard--and the screw which it operates, for shifting to in and out of gear. the patentees and makers of this type of gear are messrs. croom & arthur, victoria dock, leith, who, in addition to fitting it to the three north german lloyd steamers named in the title--which are each of , tons, having an -inch rudder-stock--have applied it to the hamburg and australian liner meissen of , tons and -inch rudder stock, and to the steamer carisbrook of , tons, owned in leith. on the latter vessel, which was the first fitted with it, the gear has been working for over two years, giving, we are told, entire satisfaction to the owners, who say the spring buffers undoubtedly reduce the vibration when the rudder is struck by a sea, and the arrangement of quadrant and tiller appears to give increase of power. of the installation of this gear on board the three north german lloyd vessels, the agents of that company say: "it has been working to our entire satisfaction. this system, on the whole, proves to have answered its purpose." considering the advantages claimed for the gear, this is satisfactory testimony. we are indebted to the london engineer for the cuts and description. * * * * * combined steam pumping and motive power engine. we give herewith an illustration of a compact engine, designed by messrs. merryweather & sons, of london, particularly for mining work, and already supplied to the burma ruby mines, the salamanca tin mines, and several mining companies in brazil and other parts of south america. it is an arrangement of the valiant steam pumping engine with a flywheel arranged to take a belt, and is so constructed that the pump can be readily thrown out of gear and the engine used to drive light machinery. the smaller size weighs only cwt., including boiler, engine and pump complete, and can be run on its own wheels, or these can be detached and the machine carried by eight or ten men on shoulder poles passed through rings fitted on top of the boiler. thus it can be easily transported up country, and has for this reason been found most useful for prospecting. for alluvial mining it will throw a powerful jet at lb. to lb. pressure, or by means of a belt will drive an experimental quartz crusher or stamp mill. the power developed is six horses, and the boiler will burn wood or other inferior fuel when coal is not obtainable. the pump will deliver gallons per minute, on a short length of hose or piping, and will force water through three or four miles of piping on the level, or, on a short length, gallons per minute against a head of feet. the pump is made entirely of gun metal, with rubber valves, and has large suction and delivery branches. air vessels are fitted, and the motion work is simple and strong. the boiler is merryweather's water tube type, and raises steam rapidly, while the fittings include feed pump, injector, safety valve, steam blast and an arrangement for feeding the boiler from the main pump in case of necessity. [illustration: merryweather's pumping engine.] we are indebted to the london engineer for the engraving and description. * * * * * some romances and exaggerations of which the pitch lake, at trinidad, has been the subject, are corrected by mr. albert cronise, of rochester, n.y. its area, height and distance from the sea have been overestimated, and a volcanic action has been ascribed to it which does not really exist. it is one mile from the landing place, is feet above the sea level, is irregular, approximately round, and has an area of acres. its surface is a few feet higher than the ground immediately around it, having been lifted up by the pressure from below. the material of the lake is solid to a depth of several feet, except in a few spots in the center, where it remains soft, but usually not hot or boiling. but as the condition of the softest part varies, it may be that it boils sometimes. the surface of the lake is marked by fissures two or three feet wide and slightly depressed spots, all of which are filled with rainwater. in going about one has to pick his way among the larger puddles and jump many of the smaller connecting streams. each of the hundreds of irregular portions separated by this network of fissures is said to have a slow revolving motion upon a horizontal axis at right angles to a line from the center of the lake, the surface moving toward the circumference. this motion is supposed to be caused by the great daily change in temperature, often amounting to °, and an unequal upward motion of the mass below, increasing toward the center of the lake. a few patches of shallow earth lying on the pitch, and covered with bushes and small trees, are scattered over the surface of the lake. * * * * * the gardeners' chronicle announces that mr. fetisoff, an amateur horticulturist at voronezh, russia, has achieved what was believed to be impossible, the production of jet black roses. no details of the process have been received. * * * * * recent books. * * * * * electro-metallurgy. electric smelting and refining: the extraction and treatment of metals by means of the electric current. being the second edition of elektro-metallurgie by dr. w. borchers. translated, with additions, by walter g. mcmillan. with plates and numerous illustrations in the text. vo, cloth. pages. london and new york, $ . electro-technical series. by edwin j. houston, ph.d., and a.e. kennelly, d.sc. ten volumes: alternating electric currents, electric heating, electro-magnetism, electricity in electro-therapeutics, electric arc lighting, electric incandescent lighting, electric motors, electric street railways, electric telephony, electric telegraphy. each $ . engineers. the practical management of engines and boilers, including boiler setting, pumps, injectors, feed water heaters, steam engine economy, condensers, indicators, slide valves, safety valves, governors, steam gages, incrustation and corrosion, etc. a practical guide for engineers and firemen and steam users generally. by william b. le van. mo, cloth. pages. illustrations. $ . experimental science. by george m. hopkins. this book treats on the various topics of physics in a popular and practical way. it describes the apparatus in detail, and explains the experiments in full, so that teachers, students and others interested in physics may readily make the apparatus without expense and perform the experiments without difficulty. the aim of the writer has been to render physical experimentation so simple and attractive as to induce both old and young to engage in it for pleasure and profit. a few simple arithmetical problems comprise all of the mathamatics of the book. many new experiments are here described for the first time. it is the most thoroughly illustrated work over published on experimental physics. pages. over illustrations. seventeenth edition. revised and enlarged. vo, cloth $ . explosives. lectures on explosives. a course of lectures prepared especially as a manual and guide in the laboratory of the united states artillery school. by willoughby walke, first lieut. fifth united states artillery. second edition. revised and enlarged. vo, cloth. pages. new york, $ . feeds and feeding. a handbook for the student and stockman. by w.a. henry. vo, cloth. pages. $ . * * * * * our large catalogue of american and foreign scientific and technical books, embracing more than fifty different subjects, and containing pages, will be mailed, free, to any address in the world. any of the foregoing books mailed, on receipt of price, to any address. remit by draft, postal note, check, or money order, to order of munn & co., broadway, new york. * * * * * a complete electrical library by prof. t. o'conor sloane, comprising five books, as follows: arithmetic of electricity, pages $ . electric toy making, pages . how to become a successful electrician, pp. . standard electrical dictionary, pages . electricity simplified, pages . --the above five books by prof. sloane may be purchased singly at the published prices, or the set complete, put up in a neat folding box, will be furnished to scientific american readers at the special reduced price of five dollars. you save $ by ordering the complete set. five volumes, , pages, and over illustrations. --send for full table of contents of each of the books. --our complete book catalogue of pages, containing reference to works of a scientific and technical character, will be sent free to any address on application. _we cannot permit the receipt of sloane's electrical library to pass by without complimenting you upon the same. it is a most admirable work. should be in the hands of all those who are interested in electricity._ _phillips, ormonde & co., engineers._ _melbourne, victoria._ _i was highly pleased with the copy of sloane's electrical library, which arrived in good condition. it is one of the most valuable works i possess in my library. the use of the roentgen rays in my profession has stimulated my desire for electrical knowledge greatly, and i consider sloane's "electrical dictionary" a first-class book of reference. i shall be pleased to recommend it to my colleagues in search of such a work. yours truly,_ _p.j. clendinnin, m.d.,_ _hon. medical electrician to the melbourne hospital._ munn & co., publishers, new york. * * * * * _just published._ second edition, revised and much enlarged. gas, gasoline and oil engines by gardner d. hiscox, m.e. the only american book on the subject. this is a book designed for the general information of every one interested in this new and popular motive power, and its adaptation to the increasing demand for a cheap and easily managed motor requiring no licensed engineer. the book treats of the theory and practice of gas, gasoline and oil engines, as designed and manufactured in the united states. it also contains chapters on horseless vehicles, electric lighting, marine propulsion, etc. second edition. illustrated by engravings. revised and enlarged. large octavo. pages. price $ . . * * * * * contents. chapter i.--introductory, historical. chapter ii.--theory of the gas and gasoline engine. chapter iii.--utilization of heat and efficiency in gas engines. chapter iv.--heat efficiencies. chapter v.--retarded combustion and wall cooling. chapter vi.--causes of loss and inefficiency in explosive motors. chapter vii.--economy of the gas engine for electric lighting. chapter viii.--the material of power in explosive engines, gas, petroleum products and acetylene gas. chapter ix.--carbureters and vapor gas for explosive motors. chapter x.--cylinder capacity of gas and gasoline engines, mufflers on gas engines. chapter xi--governors and valve gear. chapter xii.--igniters and exploders, hot, tube and electric. chapter xiii.--cylinder lubrication. chapter xiv--on the management of explosive motors. chapter xv.--the measurement of power by prony brakes, dynamometers and indicators, the measurement of speed, the indicator and its work, vibrations of buildings and floors by the running of explosive motors. chapter xvi.--explosive engine testing. chapter xvii.--various types of gas and oil engines, marine and vehicle motors.--chapter xviii.--various types of gas and oil engines. marine and vehicle motors--continued. chapter xix--united states patents on gas, gasoline and oil engines and their adjuncts-- to inclusive--list of the manufacturers of gas, gasoline and oil engines in the united states, with their addresses. * * * * * a few extracts of notices from the press. it is a very comprehensive and thoroughly up-to-date work.--_american machinist._ the subjects treated in this book are timely and interesting, as there is no doubt as to the increasing use of gas, gasoline and oil engines, particularly for small powers. it gives such general information on the construction, operation and care of these engines that should prove valuable to any one in need of such motors, as well as those already having them in use.--_machinery._ _what an engineer says_: _i beg to acknowledge receipt of your book on gas, gasoline and oil engines, by hiscox, by registered mail. i am highly pleased with the book. it is the best on oil engines i have ever seen, is not intricate in the calculations, and the illustrations are excellent. yours truly,_ _s. dalrymple, chief-engineer s.s. "talune."_ _melbourne, victoria._ munn & co., publishers, scientific american office, broadway, new york. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . stitched in paper, or $ . bound in stiff covers. combined rates.--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway, new york, n.y. * * * * * special naval supplement, no. , contains a historical review of the modern united states navy, the classification of the various forms of war vessels and nearly one hundred illustrations, including details of construction of such vessels not found in any other publication. a map of cuba printed in five colors accompanies it. price, cents. single copies sent by mail in united states, canada and mexico. foreign countries, cents extra. munn & co., broadway, new york. * * * * * supplement catalogue ready! the publishers of the scientific american announce that an entirely new page supplement catalogue is now ready for distribution, and will be sent free to all on application. munn & co., publishers, broadway, new york city. * * * * * building edition of the scientific american. those who contemplate building should not fail to subscribe. only $ . a year. semi-annual bound volumes $ . each, yearly bound volumes $ . each, prepaid by mail. each number contains elevations and plans of a variety of country houses; also a handsome colored plate. munn & co., broadway, new york. * * * * * patents! messrs. munn & co., in connection with the publication of the scientific american, continue to examine improvements, and to act as solicitors of patents for inventors. in this line of business they have had _fifty years' experience_, and now have _unequaled facilities_ for the preparation of patent drawings, specifications, and the prosecution of applications for patents in the united states, canada, and foreign countries. messrs. munn & co. also attend to the preparation of caveats, copyrights for books, trade marks, reissues, assignments, and reports on infringements of patents. all business intrusted to them is done with special care and promptness, on very reasonable terms. a pamphlet sent free of charge, on application, containing full information about patents and how to procure them; directions concerning trade marks copyrights, designs, patents, appeals, reissues, infringements, assignments, rejected cases, hints on the sale of patents, etc. we also send, _free of charge_, a synopsis of foreign patent laws showing the cost and method of securing patents in all the principal countries of the world. munn & co., solicitors of patents, broadway, new york. branch offices.--no. f street, washington. d.c. none [illustration] scientific american supplement no. . new york, june , . scientific american supplement. vol. xvii., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. chemistry and metallurgy.--beeswax and its adulterations. --chemical ingredients.--detection of adulterations. phenol in the stem, leaves, and cones of pinus sylvestris. --a discovery bearing on the flora of the carboniferous epoch and the formation of petroleum. the school of physics and chemistry of paris.--with engraving of laboratory. some relations of heat to voltaic and thermo electric action of metals in electrolysis.--by g. gore. ii. engineering, mechanics, etc.--air refrigerating machine.-- figures. a gas radiator and heater. concrete water pipes. the sellers standard system of screw threads. nuts, and bolt heads.--a table. an english railway ferry boat.-- figures. the problem of flight and the flying machine. iii. technical.--concrete buildings for farms.--how to construct them. what causes paint to blister and peel?--how to prevent it. olive oil.--difficulties encountered in raising an olive crop.--process of making oil. iv. electricity. etc.--telephony and telegraphy on the same wires simultaneously.-- figures. the electric marigraph.--an apparatus for measuring the height of the tide.--with engravings and diagrams showing the siemens and halske marigraph and the operation of the same. delune & co.'s system of laying underground cables.-- figures. electricity applied to horseshoeing.--quieting an unruly animal.-- engravings. esteve's automatic pile.-- figure. woodward's diffusion motor. v. astronomy.--lunar heat.--its reflected and obscure heat.--trifling influence of the moon upon wind and weather.--by prof. c.a. young. vi. natural history.--the long-haired pointer "mylord." --with engraving. vii. horticulture, etc.--apple tree borers.--protection against the same. keffel's germinating apparatus.--with engraving. millet.--its cultivation. viii. miscellaneous.--puerta del sol, madrid, spain.--with engraving. dust-free spaces.--a lecture delivered by dr. oliver j. lodge before the royal dublin society. * * * * * puerta del sol, madrid. puerta del sol, or gate of the sun, madrid, is the most famous and favorite public square in the spanish city of madrid. it was the eastern portal of the old city. from this square radiate several of the finest streets, such as alcala, one of the handsomest thoroughfares in the world, mayor, martera, carretas, geronimo. in our engraving the post office is seen on the right. large and splendid buildings adorn the other sides, which embrace hotels, cafes, reading rooms, elegant stores, etc. from this square the street railway lines traverse the city in all directions. the population of the city is about , . it contains many magnificent buildings. our engraving is from _illustrirte zeitung_. [illustration: the puerta del sol, madrid, spain (from a photograph.)] * * * * * concrete buildings for farms. buildings made of concrete have never received the attention in this country that they deserve. they have the merit of being durable and fire-proof, and of not being liable to be blown down by violent winds. it is very easy to erect them in places where sand and gravel are near at hand and lime is comparatively cheap. experiments made in england show that coal screenings may be employed to good advantage in the place of sand and gravel. mr. samuel preston, of mount carroll, ill., has a dwelling and several other buildings made of concrete and erected by himself. they were put up in , and are in excellent condition. in _the farmers' review_ he gives the following directions for building concrete walls: first, secure a good stone foundation, the bottom below frost, the top about one foot above ground. near the top of the foundation bed in × scantling edgewise transversely with the walls, at such distances apart as the length of the planks that form the boxes to hold the concrete may require, the ends of the scantling to run six inches beyond the outside and inside of the wall. now take × studding, one foot longer than the height of the concrete walls are to be, bolt in an upright position in pairs to each end of the × scantling, and, if a foot wall is to be built, sixteen inches apart, as the box plank will take up four inches. to hold the studding together at the top, take pieces of × lumber, make two mortises in each piece large enough to slip easily up and down on the studding, forming a tie. make one mortise long enough to insert a key, so that the studding can be opened at the top when the box plank are to be raised. when the box plank are in position, nail cleats with a hole in each of them on each side of the studding, and corresponding holes in the studding, into which insert a pin to hold the plank to the studding. bore holes along up in the studding, to hold the boxes when raised. to make the walls hollow, and i would do it in a building for any purpose, use inch boards the same width of the box plank, one side planed; put the two rough sides together with shingles between, nailing them together with six-penny nails; place them in the middle of the wall, the thin end of the shingle down. that gives them a bevel and can be easily raised with the boxes. to tie the wall together, at every third course place strips of boards a little shorter than the thickness of the wall; cut notches in each so that the concrete will fill in, holding all fast. the side walls being up, place two inch planks on top of the wall upon which to rest the upper joists, put on joist and rafters, remove the box plank, take inch boards for boxes, cut to fit between joists and rafters, and fill with concrete to upper side of rafters, which makes walls that will keep out cold and damp, all kinds of vermin, and a roof which nothing but a cyclone can remove. in making door and window frames, make the jambs two inches narrower than the thickness of the walls, nailing on temporary two inch strips. make the mortar bed large enough to hold the material for one course; put in unslaked quicklime in proportion to to or of other material; throw into it plenty of water, and don't have that antediluvian idea that you can drown it; put in clean sand and gravel, broken stone, making it thin enough, so that when it is put into boxes the thinner portion will run in, filling all interstices, forming a solid mass. a brick trowel is necessary to work it down alongside the boxing plank. one of the best and easiest things to carry the concrete to the boxes is a railroad wheelbarrow, scooping it in with a scoop shovel. two courses a week is about as fast as it will be safe to lay up the walls. * * * * * the _medical summary_ recommends the external use of buttermilk to ladies who are exposed to tan or freckles. * * * * * what causes paint to blister and peel? how to prevent it. this subject has been treated by many, but out of the numerous ideas that have been brought to bear upon it, the writers have failed to elucidate the question fully, probably owing to the fact that in most parts they were themselves dubious as to the real cause. last year w.s. gave a lengthy description in the _building news_, in which he classified blistering and peeling of paint into one of blistering only. he stated in the beginning of his treatise the following: "the subject of blistering of paint has from time to time engrossed the attention of practical men; but so far as we can follow it in the literature pertaining to the building trade, its cause has never been clearly laid down, and hence it is a detail enshrouded in mystery." w.s. dwells mostly, in his following explanations on blistering paints, on steam raised in damp wood. also an english painter, according to the _painters' journal_, lately reiterates the same theory, and gives sundry reasons how water will get into wood through paint, but is oblivious that the channels which lead water into wood are open to let it out again. he lays great stress on boiled oil holding water in suspense to cause blistering, which is merely a conjecture. water boils at ° f. and linseed oil at ° f., consequently no water can possibly remain after boiling, and a drop of water put into boiling oil would cause an explosion too dangerous to be encountered. it will be shown herewith that boiled oil, though in general use, is unfit for durable painting, that it is the cause of most of the troubles painters have to contend with, and that raw linseed oil seasoned by age is the only source to bind pigments for durable painting; but how to procure it is another trouble to overcome, as all our american raw linseed oil has been heated by the manufacturers, to qualify it for quick drying and an early market, thereby impairing its quality. after linseed oil has been boiled, it becomes a poor varnish; it remains soft and pliable when used in paint, giving way to air pressure from the wood in hot weather, forming blisters. turpentine causes no blistering; it evaporates upon being exposed, and leaves the paint in a porous condition for the gas in the wood to escape; but all painters agree that blistering is caused by gas, and on investigation we find two main sources from which gas is generated to blister paint--one from the wood, the other from the ingredients of the paint. the first named source of gas is started in hot weather by expansion of air confined in painted wood, which presses against the paint and raises blisters when the paint is too soft to resist. tough, well-cemented paint resists the pressure and keeps the air back. these blisters mostly subside as soon as the air cools and returns to the pores, but subsequently peel off. w.s. and others assert that damp in painted wood turns into steam when exposed to sun heat, forming blisters, which cannot be possible when we know that water does not take a gaseous form (steam) at less than ° f. they have very likely been deluded by the known way of distilling water with the aid of sunshine without concentrating the rays of the sun, based upon the solubility of water in air, viz.: air holds more water in solution (or suspension) in a warmer than in a cooler degree of temperature; by means of a simple apparatus sun-heated air is guided over sun-heated water, when the air saturated with water is conducted into a cooler, to give up its water again. but water has an influence toward hastening to blister paint; it holds the unhardened woodsap in solution, forming a slight solvent of the oil, thereby loosening the paint from the wood, favoring blistering and peeling. there is a certain kind of blister which appears in certain spots or places only, and nowhere else, puzzling many painters. the explanation of this is the same as before--soft paint at these spots, caused by accident or sluggish workmen having saturated the wood with coal oil, wax, tar, grease, or any other paint-softening material before the wood was painted, which reacts on the paint to give way to air pressure, forming blisters. the second cause of paint blistering from the ingredients of the paint happens between any layer of paint or varnish on wood, iron, stone, or any other substance. its origin is the gaseous formation of volatile oils during the heated season, of which the lighter coal oils play the most conspicuous part; they being less valuable than all other volatile oils, are used in low priced japan driers and varnishes. these volatile oils take a gaseous form at different temperatures, lie partly dormant until the thermometer hovers at ° f. in the shade, when they develop into gas, forming blisters in airtight paint, or escape unnoticed in porous paint. this is the reason why coal-tar paint is so liable to blister in hot weather; an elastic, soft coal-tar covering holds part of its volatile oil confined until heated to generate into gas; a few drops only of such oil is sufficient to spoil the best painted work, and worse, when it has been applied in priming, it settles into the pores of the wood, needing often from two to three repetitions of scraping and repainting before the evil is overcome. now, inasmuch as soft drying paint is unfit to answer the purpose, it is equally as bad when paint too hard or brittle has been used, that does not expand and contract in harmony with the painted article, causing the paint to crack and peel off, which is always the case when either oil or varnish has been too sparingly and turpentine too freely used. intense cold favors the action, when all paints become very brittle, a fact much to be seen on low-priced vehicles in winter time. damp in wood will also hasten it, as stated in blistering, the woodsap undermining the paint. to avoid peeling and blistering, the paint should be mixed with raw linseed oil in such proportions that it neither becomes too brittle nor too soft when dry. priming paint with nearly all oil and hardly any pigment is the foundation of many evils in painting; it leaves too much free oil in the paint, forming a soft undercoat. for durable painting, paint should be mixed with as much of a base pigment as it can possibly be spread with a brush, giving a thin coat and forming a chemical combination called soap. to avoid an excess of oil, the following coats need turpentine to insure the same proportion of oil and pigment. as proof of this, prime a piece of wood and a piece of iron with the same paint; when the wood takes up part of the oil from the paint and leaves the rest in proportion to harden well, where at the same time the paint on iron remains soft. to be more lucid, it need be explained, linseed oil boiled has lost its oleic acid and glycerine ether, which form with the bases of pigments the insoluble soap, as well as its albumen, which in boiling is thrown out. it coagulates at ° f. heat; each is needed to better withstand the action of wind and weather, preventing the dust from attaching itself to a painted surface, a channel for ammonia in damp weather to dissolve and wash off the paint. in later years linseed oil has been extracted from linseed meal by the aid of naphtha and percolation, the product of a very clear, quick drying oil, but lacking in its binding quality, no doubt caused by the naphtha dissolving the fatty matter only, leaving the glycerine and albumen in the meal. all pigments of paint group according to their affinity to raw linseed oil into three classes. first, those that form chemical combinations, called soap. this kind is the most durable, is used for priming purposes, and consists of lead, zinc, and iron bases, of which red lead takes up the most oil; next, white lead, the pure carbonate dutch process made, following with zinc white and iron carbonates, as iron ore paint, turkey umber, yellow ocher; also faintly the chromates of lead--chrome-green and chrome-yellow, finishing with the poorest of all, modern white lead, made by the wet or vinegar process. the second class being neutrals have no chemical affinity to linseed oil; they need a large quantity of drier to harden the paint, and include all blacks, vermilion, prussian, paris, and chinese blue, also terra di sienna, vandyke brown, paris green, verdigris, ultramarine, genuine carmine, and madderlake. the last seven are, on account of their transparency, better adapted for varnish mixtures--glazing. the third class of pigments act destructively to linseed oil; they having an acid base (mostly tin salt, hydrochloride of tin, and redwood dye), form with the gelatinous matter of the oil a jelly that will neither work well under the brush nor harden sufficiently, and can be used in varnish for glazing only; they are not permanent in color, and among the most troublesome are the lower grades of so-called carmines, madderlakes, rose pinks, etc., which contain more or less acidous dyes, forming a soft paint with linseed oil that once dry on a job can be twisted or peeled off like the skin of a ripe peach. all these combinations of paint have to be closely observed by the painter to insure his success. twenty-five years ago a house needed to be painted outside but once in from five to seven years; it looked well all the time, as no dust settled in the paint to make it unsightly. painters then used the dutch-process-made white-lead, a base and raw linseed oil, a fat acid, which formed the insoluble soap. they also put turpentine in the following coats, to keep up the proportions of oil and pigment. all held out well against wind and weather. now they use the wet-process-made white lead, neutralized by vinegar, with oil neutralized by boiling, from the first to the last coat, and--fail in making their work permanent. w.s., in the _building news_, relates an unaccountable mysterious blistering in a leaky house, where the rainwater came from above on a painted wood wall, blistering the paint in streaks and filled at the lower ends with water, which no doubt was caused by the water soaking the wood at the upper ends where there was no paint, and following it down through the fibers, pushed and peeled off the soft, inadhesive paint. green, sappy, and resinous wood is unfit for durable painting, and to avoid blistering and peeling wood should be well seasoned and primed with all raw linseed oil, some drier, to insure a moderately slow drying, and as much of a base pigment as the painter can possibly spread (much drier takes up too much oil acid, needed for the pigment base to combine with), which insures a tough paint that never fails to stand against blistering or peeling, as well as wind, weather, and ammonia. the coach, car, and house painter can materially improve his painting where his needs lie by first oiling the wood with raw oil, then smoothing the surface down with lump pumicestone, washing it with a mixture of japan drier or, better yet, gold sizing and turpentine, wiping dry, and following it up with a coat of white lead, oil, and turpentine. the explanation is: the raw oil penetrates the wood and raises the wood fibers on the surface to be rubbed down with pumicestone, insuring the best surface for the following painting: to harden the oil in the wood it receives a coat of japan drier, which follows into the pores and there forms a tough, resinous matter, resisting any air pressure that might arise from within, and at the same time reacts on the first coat of lead as a drier. this mode insures the smoothest and toughest foundation for the following painting, and may be exposed to the hottest july sun without fear of either blistering or peeling. louis matern. bloomington, ill. * * * * * olive oil. the following particulars with regard to the production of olive oil in tuscany have been furnished to mr. consul inglis by one of the principal exporters in leghorn: the olive oil produced in tuscany from the first pressing of the fruit is intended for consumption as an article of food. hence, great attention is paid both to the culture of the olive tree and the process of making oil. the olive crop is subject to many vicissitudes, and is an uncertain one. it may be taken as a rule that a good crop does not occur more frequently than once in three years. a prolonged drought in summer may cause the greater part of the small fruit to fall off the trees. a warm and wet autumn will subject the fruit to the ravages of a maggot or worm, which eats its way into it. fruit thus injured falls to the ground prematurely, and the oil made from it is of very bad quality, being nauseous in taste and somewhat thick and viscous. frost following immediately on a fall of snow or sleet, when the trees are still wet, will irretrievably damage the fruit, causing it to shrivel up and greatly diminishing the yield of oil, while the oil itself has a dark color, and loses its delicate flavor. the olive tree in tuscany generally blossoms in april. by november the fruit has attained its full size, though not full maturity, and the olive harvest generally commences then. the fruit, generally speaking, is gathered as it falls to the ground, either from ripeness or in windy weather. in some districts, however, and when the crop is short, the practice is to strip the fruit from the trees early in the season. when there is a full crop the harvest lasts many months, and may not be finished till the end of may, as the fruit does not all ripen simultaneously. oil made early in the season has a deeper color, and is distinguished by a fruity flavor, with a certain degree of pungency; while as the season advances it becomes lighter in color, thinner in body, and milder and sweeter in taste. oil made toward the close of the harvest in april or may from extremely ripe fruit is of a very pale straw color, mild and sweet to the taste, though sometimes, if the fruit has remained too long on the trees, it may be slightly rancid. oil very light in color is much prized in certain countries, notably france, and hence, if it also possesses good quality, commands a higher price in the tuscan markets. the fruit of the olive tree varies just as much in quality as does the grape, according to the species of the tree itself, the nature of the soil, exposure, and climate of the locality where it grows. some varieties of the olive tree largely grown, because thought to be better suited to the special conditions of some districts, yield a fruit which imparts a bitter taste to the oil made from it; such oil, even when otherwise perfect, ranks as a second rate quality. the highest quality of oil can only be obtained when the fruit is perfectly and uniformly sound, well ripened, gathered as soon as it has dropped from the trees, and crushed immediately with great attention. should the fruit remain any time on the ground, particularly during wet weather, it deteriorates fast and gets an earthy taste; while if allowed to remain an undue length of time in the garners it heats, begins to decompose, and will yield only bad oil. the process of making oil is as follows: the fruit is crushed in a stone mill, generally moved by water power; the pulp is then put into bags made of fiber, and a certain number of these bags, piled one upon another, are placed in a press, most frequently worked by hand; when pressure is applied, the oil flows down into a channel by which it is conveyed to a receptacle or tank. when oil ceases to flow, tepid water is poured upon the bags to carry off oil retained by the bags. the pulp is then removed from the bags, ground again in the mill, then replaced in the bags, and pressed a second time. the water used in the process of making oil must be quite pure; the mill, press, bags, and vessels sweet and clean, as the least taint would ruin the quality of the oil produced. the oil which has collected in the tank or receptacle just mentioned is removed day by day, and the water also drained off, as oil would suffer in quality if left in contact with water; the water also, which necessarily contains some oil mingled with it, is sent to a deposit outside, and at some distance from the crushing house, which is called the "inferno," where it is allowed to accumulate, and the oil which comes to the surface is skimmed off from time to time. it is fit only for manufacturing purposes. after the second pressing the olive-pulp is not yet done with; it is beaten up with water by mechanical agitators moved by water-power, and then the whole discharged into open-air tanks adjoining the crushing house. there the crushed olive kernels sink to the bottom, are gathered up and sold for fuel, fetching about francs per , kilos, while the _debris_ of the pulp is skimmed off the surface of the tank and again pressed in bags, yielding a considerable quantity of inferior oil, called "olio lavato," or washed oil, which, if freshly made, is even used for food by the poorer classes. the pulp then remaining has still further use. it is sold for treatment in factories by the sulphide of carbon process, and by this method yields from seven to nine per cent. of oil, of course suitable only for manufacturing purposes. only the first two pressings yield oil which ranks as first quality, subject of course to the condition of the fruit being unexceptionable. new oil is allowed to rest a while in order to get rid of sediment; it is then clarified by passing through clean cotton wool, when it is fit for use. the highest quality of olive oil for eating purposes should not only be free from the least taint in taste or smell, but possessed of a delicate, appetizing flavor. when so many favorable conditions are needed as to growth, maturity, and soundness of the fruit, coupled with great attention during the process of oil-making, it is not to be wondered at that by no means all or even the greater part of the oil produced in the most favored districts of tuscany is of the highest quality. on the contrary, the bulk is inferior and defective. these defective oils are largely dealt in both for home consumption and export, when price and not quality is the object. in foreign countries there is always a market for inferior, defective olive oil for cooking purposes, etc., provided the price be low. price and not quality is the object, so much so that when olive oil is dear, cotton-seed, ground-nut, and other oils are substituted, which bear the same relation to good olive oil that butterine and similar preparations do to real butter. the very choicest qualities of pure olive oil are largely shipped from leghorn to england, along with the very lowest qualities, often also adulterated. the oil put into florence flasks is of the latter kind. many years back this was not the case, but now it is a recognized fact that nothing but the lowest quality of oil is put into these flasks; oil utterly unfit for food, and so bad that it is a mystery to what use it is applied in england. importers in england of oil in these flasks care nothing, however, about quality; cheapness is the only desideratum. the best quality of tuscan olive oil is imported in london in casks, bottled there, and bears the name of the importers alone on the label. there is no difficulty in procuring in england the best tuscan oil, which nothing produced elsewhere can surpass; but consumers who wish to get, and are willing to pay for, the best article must look to the name and reputation of the importers and the general excellence of all the articles they sell, which is the best guarantee they can have of quality. * * * * * beeswax and its adulterations. beeswax is a peculiar waxy substance secreted only by bees, and consisting of . per cent. carbon, . per cent. hydrogen, and . per cent. oxygen. it is a mixture of myricine, cerotic acid, and cerolein, the first of which is insoluble in boiling alcohol, the second is soluble in hot alcohol and crystallizes out on cooling, while the third remains dissolved in cold alcohol. although we are unable to produce real beeswax artificially, there are many imitations which are made use of to adulterate the genuine article, and their detection is a matter of considerable difficulty. huebl says (_dingl. jour._, p. ) that the most reliable method of estimating the adulteration of beeswax is that proposed by becker, and known as the saponification method. the quantity of potassic hydrate required to saponify one gramme or grains of pure beeswax varies from to milligrammes. other kinds of wax and its substitutes require in some cases more and in others less of the alkali. this method would, however, lead to very erroneous conclusions if applied to a mixture of which some of the constituents have higher saponification numbers than beeswax and others higher, as one error would balance the other. to avoid this, the quantity of alkali required to saponify the myricine is first ascertained, and then that required to saturate the free cerotic acid. in this way two numbers are obtained; and in an investigation of twenty samples of austrian yellow beeswax, the author found these numbers stood to each other almost in the constant ratio of to . . although this ratio cannot be considered as definitely established by so few experiments, it may serve as a guide in judging of the purity of beeswax. the experiment is carried out as follows: or grammes of the wax that has been melted in water are put in c.c. of neutral per cent, alcohol, and warmed until the wax melts, when phenolphthaleine is added, and enough of an alcoholic solution of potash run in from a burette until on shaking it retains a faint but permanent red color. the burette used by the author is divided in . c.c. after adding c.c. more of a half normal potash solution, it is heated on a water bath for ¾ hour. then the uncombined excess of alkali is titrated with half normal hydrochloric acid. the alcohol must be tested as to its reaction before using it, and carefully neutralized with the acid of phenolphthalein. to saturate the free acid in gramme of wax requires to milligrammes of potassic hydrate, while to milligrammes more are necessary to saponify the myricine ether. the lower numbers in the one usually occur with low numbers for the other, so that the proportions remain to . or to . . for comparison he gives the following numbers obtained with one gramme of the more common adulterants: ----------------+----------+----------+---------+--------+ | to | to | total | | |neutralize| convert |saponifi-| | | the acid.|the ether.| cation. | ratio. | ----------------+----------+----------+---------+--------+ japanese wax | | | | | carnauba wax | | | | | tallow | | | | | stearic acid | | | | / | rosin | | . | | . | paraffine | | | | | ceresine | | | | | yellow beeswax | | | | . | ----------------+----------+----------+---------+--------+ the author deduces the following conclusions as the results of these investigations: . if the numbers obtained lie between these limits, to , to , to , and . to . respectively, it may be assumed that the beeswax is pure, provided it also corresponds to beeswax in its physical properties. . if the saponification figures fall below and yet the ratio is correct, it is adulterated with some neutral substance like paraffine. . if the ratio is above . , it is very probable that japanese or carnauba wax or grease has been added. . if the ratio falls below . , stearic acid or resin has been used as the adulterant. * * * * * phenol in the stem, leaves, and cones of pinus sylvestris. a discovery bearing on the flora of the carboniferous epoch and the formation of petroleum. by a.b. griffiths, ph.d., f.c.s. membre de la societe chimique de paris, medallist in chemistry and botany, etc. having found, in small quantities, alcohols of the c_{n}h_{ n- } series, last summer, in the stem, acicular leaves, and cones of _pinus sylvestris_, i wish in this paper to say a few words on the subject. first of all, i took a number of cones, cut them up into small pieces, and placed them in a large glass beaker, then nearly filled it with distilled water, and heated to about ° c., keeping the decoction at this temperature for about half an hour, i occasionally stirred with a glass rod, and then allowed it to cool, and filtered. this filtrate was then evaporated nearly to dryness, when a small quantity of six-sided prisms crystallized out, which subsequently were found to be the hydrate of phenol (c_{ }h_{ }ho)_{ }h_{ }o. its melting point was found to be . ° c. further, the crystals already referred to were dissolved in ether, and then allowed to evaporate, when long colorless needles were obtained, which, on being placed in a dry test tube and the tube placed in a water bath kept at ° c., were found to melt; and on making a careful combustion analysis of these crystals, the following composition was obtained: carbon . hydrogen . oxygen . ----- . this gives c_{ }h_{ }o, which is the formula for phenol. on dissolving some of these crystals in water (excess) and adding ferric chloride, a beautiful violet color was imparted to the solution. to another aqueous solution of the crystals was added bromine water, and a white precipitate was obtained, consisting of tribromophenol. an aqueous solution of the crystals immediately coagulated albumen. all these reactions show that the phenol occurs in the free state in the cones of this plant. in the same manner i treated the acicular leaves, and portions of the stem separately, both being previously cut up into small pieces, and from both i obtained phenol. i have ascertained the relative amount of phenol in each part of the plant operated upon; by heating the stem with water at ° c., and filtering, and repeating this operation until the aqueous filtrate gave no violet color with ferric chloride and no white precipitate with bromine water. i found various quantities according to the age of the stem. the older portions yielding as much as . per cent, while the young portions only gave . per cent. the leaves yielding according to their age, . and . per cent.; and the cones also gave varying amounts, according to their maturity, the amounts varying between . and . . two methods were used in the quantitative estimation of the amount of phenol. the first was the new volumetric method of m. chandelon (_bulletin de la societe chemique de paris_, july , ; and _deutsch-americanishe apotheker zeitung_, vol. iii., no. , september , ), which i have found to be very satisfactory. the process depends on the precipitation of phenol by a dilute aqueous solution of bromine as tribromophenol. the second method was to extract, as already staled, a known weight of each part of the plant with water, until the last extract gives _no_ violet color with ferric chloride, and no white precipitate with the bromine test (which is capable of detecting in a solution the / part of phenol). the aqueous extract is at this point evaporated, then ether is added, and finally the ethereal solution is allowed to evaporate. the residue (phenol) is weighed directly, and from this the percentage can be ascertained. by this method of extraction, the oil of turpentine, resins, etc., contained in _pinus sylvestris_ do not pass into solution, because they are insoluble in water, even when boiling; what passes into solution besides phenol is a little tannin, which is practically insoluble in ether. from this investigation it will be seen that phenol exists in various proportions in the free state in the leaves, stem, and cones of _pinus sylvestris_, and as this compound is a product in the distillation of coal, and as geologists have to a certain extent direct evidence that the flora of the carboniferous epoch was essentially crytogamous, the only phænogamous plants which constituted any feature in "the coal forests" being the coniferæ, and as coal is the fossil remains of that gigantic flora which contained phenol, i think my discovery of phenol in the coniferæ of the present day further supports, from a chemical point of view, the views of geologists that the coniferæ existed so far back in the world's history as the carboniferous age. i think this discovery also supports the theory that the origin of petroleum in nature is produced by moderate heat on coal or similar matter of a vegetable origin. for we know from the researches of freund and pebal (_ann. chem. pharm._, cxv. ), that petroleum contains phenol and its homologues, and as i have found this organic compound in the coniferæ of to-day, it is probable that petroleum in certain areas has been produced from the conifers and the flora generally of some primæval forests. it is stated by numerous chemists that "petroleum almost always contains solid paraffin" and similar hydrocarbons. professors schorlemmer and thorpe have found heptane in pinus, which heptane yielded primary heptyl-alcohol, and methyl-pentyl-carbinol, exactly as the heptane obtained from petroleum does (_annalen de chemie_, ccxvii., , and clxxxviii., ; and _berichte der deutschen chemischen gesellschaft_, viii., ); and, further, petroleum contains a large number of hydrocarbons which are found in coal. again, mendelejeff, beilstein, and others (_bulletin de la societe chemique de paris_, no. , july , ), have found hydrocarbons of the-- c_{n}h_{ n +}, c_{n}h_{ n- }, also hydrocarbons of the c_{n}h_{ n} series in the petroleum of baku, american petroleum containing similar hydrocarbons. i think all these facts give very great weight to the theory that petroleum is of organic origin. on the other hand, berthelot, from his synthetic production of hydrocarbons, believes that the interior of the globe contains alkaline metals in the _free_ state, which yield acetylides in the presence of carbonic anhydride, which are decomposed into acetylene by aqueous vapor. but it has been already proved that acetylene may be polymerized, so as to produce aromatic carbides, or the derivatives of marsh gas, by the absorption of hydrogen. berthelot's view, therefore, is too imaginative; for the presence of _free_ alkaline metals in the earth's interior is an unproved and very improbable hypothesis. byasson states that petroleum is formed by the action of water, carbonic anhydride, and sulphureted hydrogen upon incandescent iron. mendelejeff thinks it is formed by the action of aqueous vapor upon carbides of iron; and in his article, "petroleum, the light of the poor" (in this month's--february--number of _good words_), sir lyon playfair, k.c.b., f.r.s., etc., holds opinions similar to those of mendelejeff. taking in consideration the facts that solid paraffin is found in petroleum and is also found in coal, and from my own work that phenol exists in _pinus sylvestris_, and has been found by others in coal which is produced from the decomposition of a flora containing numerous gigantic coniferæ allied to pinus, and that petroleum contains phenol, and each (i.e., petroleum and coal) contains a number of hydrocarbons common to both, i am inclined to think that the balance of evidence is in favor of the hypothesis that petroleum has been produced in nature from a vegetable source in the interior of the globe. of course, there can be no practical or direct evidence as to the origin of petroleum; therefore "theories are the only lights with which we can penetrate the obscurity of the unknown, and they are to be valued just as far as they illuminate our path." in conclusion, i think that there is a connecting link between the old pine and fir forest of bygone ages and the origin of petroleum in nature.--_chemical news._ * * * * * the school of physics and chemistry of paris. recently we paid a visit to the new municipal school of physics and chemistry that the city of paris founded in , and that is now in operation in the large building of the old rollin college. this establishment is one of those that supply a long-felt want of our time, and we are happy to make it known to our readers. the object for which it was designed was, in the intention of its founders, to give young people who have just graduated from the higher primary schools special instruction which shall be at once scientific and practical, and which shall fit them to become engineers or superintendents in laboratories connected with chemical and physical industries. to reach such a result it has been necessary to give the teaching an essentially practical character, by permitting the pupils to proceed of themselves in manipulations in well fitted laboratories. it is upon this important point that we shall now more particularly dwell; but, before making known the general mode of teaching, we wish to quote a few passages from the school's official programme: "many questions and problems, in physics as well as in chemistry, find their solution only with the aid of mathematics and mechanics. it therefore became necessary, through lectures bearing upon the useful branches of mathematics, to supplement the too limited ideas that pupils brought with them on entering the school. mathematics and mechanics are therefore taught here at the same time with physics and chemistry, but they are merely regarded in the light of auxiliaries to the latter. "the studies extend over three years. each of the three divisions ( st, d, and d years) includes thirty pupils. "during the three first semesters, pupils of the same grade attend lectures and go through manipulations in chemistry, physics, mathematics, and draughting in common. "at the end of the third semester they are divided into physical and chemical students. "from this moment, although certain courses still remain wholly or partially common to the two categories of pupils (physical and chemical), the same is no longer the case with regard to the practical exercises, for the physical students thereafter manipulate only in the physical laboratories, and the chemical only in the chemical laboratories; moreover, the manipulations acquire a greater importance through the time that is devoted to them. "at each promotion the three first semesters are taken up with general and scientific studies. technical applications are the subject of the lectures and exercises of the three last semesters. at the end of the third year certificates are given to those pupils who have undergone examination in a satisfactory manner, and diplomas to such as have particularly distinguished themselves." when pupils have been received at the school, after passing the necessary examination, their time of working is divided up between lectures and questionings and different laboratory manipulations. the course of lectures on general and applied physics comprises hydrostatics and heat (prof. dommer), electricity and magnetism (prof. hospitalier), and optics and acoustics (prof. baille). lectures on general chemistry are delivered by profs. schultzenberger and henninger, on analytical chemistry by prof. silva, on chemistry applied to the industries by prof. henninger (for inorganic) and prof. schultzenberger (for organic). the lectures on pure and applied mathematics and mechanics are delivered by profs. levy and roze. [illustration: general view of a laboratory at the paris school of physics and chemistry.] the pupils occupy themselves regularly every day, during half the time spent at the school, with practical work in analytical and applied chemistry and physics and general chemistry. this practical work is a complement to the various lectures, and has reference to what has been taught therein. once or twice per week the pupils spend three hours in a shop devoted to wood and metal working, and learn how to turn, forge, file, adjust, etc. the school's cabinets are now provided with the best instruments for study, and are daily becoming richer therein. the chemical laboratories are none the less remarkably organized. in the accompanying cut we give a view of one of these--the one that is under the direction of mr. schultzenberger, professor of chemistry and director of the new school. each pupil has his own place in front of a large table provided with a stand whereon he may arrange all the products that he has to employ. beneath the work-table he has at his disposal a closet in which to place his apparatus after he is through using them. each pupil has in front of him a water-faucet, which is fixed to a vertical column and placed over a sink. alongside of this faucet there is a double gas burner, which may be connected with furnaces and heating apparatus by means of rubber tubing. a special hall, with draught and ventilation, is set apart for precipitations by sulphureted hydrogen and the preparation of chlorine and other ill-smelling and deleterious gases. the great amount of light and space provided secure the best of conditions of hygiene to this fine and vast laboratory, where young people have all the necessary requisites for becoming true chemists.--_la nature._ * * * * * dust-free spaces.[ ] [footnote : lecture to the royal dublin society by dr. oliver j. lodge, april , .] within the last few years a singular interest has arisen in the subject of dust, smoke, and fog, and several scientific researches into the nature and properties of these phenomena have been recently conducted. it so happened that at the time i received a request from the secretary of this society to lecture here this afternoon i was in the middle of a research connected with dust, which i had been carrying on for some months in conjunction with mr. j.w. clark, demonstrator of physics in university college, liverpool, and which had led us to some interesting results. it struck me that possibly some sort of account of this investigation might not be unacceptable to a learned body such as this, and accordingly i telegraphed off to mr. moss the title of this afternoon's lecture. but now that the time has come for me to approach the subject before you, i find myself conscious of some misgivings, and the misgivings are founded upon this ground: that the subject is not one that lends itself easily to experimental demonstration before an audience. many of the experiments can only be made on a small scale, and require to be watched closely. however, by help of diagrams and by not confining myself too closely to our special investigation, but dealing somewhat with the wider subject of dust in general, i may hope to render myself and my subject intelligible if not very entertaining. first of all, i draw no distinction between "dust" and "smoke." it would be possible to draw such a distinction, but it would hardly be in accordance with usage. dust might be defined as smoke which had settled, and the term smoke applied to solid particles still suspended in the air. but at present the term "smoke" is applied to solid particles produced by combustion only, and "dust" to particles owing their floating existence to some other cause. this is evidently an unessential distinction, and for the present i shall use either term without distinction, meaning by dust or smoke, solid particles floating in the air. then "fog"; this differs from smoke only in the fact that the particles are liquid instead of solid. and the three terms dust, smoke, and fog, come to much the same thing, only that the latter term is applied when the suspended particles are liquid. i do not think, however, that we usually apply the term "fog" when the liquid particles are pure water; we call it then mostly either mist or cloud. the name "fog," at any rate in towns, carries with it the idea of a hideous, greasy compound, consisting of smoke and mist and sulphur and filth, as unlike the mists on a highland mountain as a country meadow is unlike a city slum. nevertheless, the finest cloud or mist that ever existed consists simply of little globules of water suspended in air, and thus for our present purpose differs in no important respect from fog, dust, and smoke. a cloud or mist is, in fact, fine water-dust. rain is coarse water-dust formed by the aggregation of smaller globules, and varying in fineness from the scotch mist to the tropical deluge. it has often been asked how it is that clouds and mists are able to float about when water is so much heavier ( times heavier) than air. the answer to this is easy. it depends on the resistance or viscosity of fluids, and on the smallness of the particles concerned. bodies falling far through fluids acquire a "terminal velocity," at which they are in stable equilibrium--their weight being exactly equal to the resistance--and this terminal velocity is greater for large particles than for small; consequently we have all sorts of rain velocity, depending on the size of the drops; and large particles of dust settle more quickly than small. cloud-spherules are falling therefore, but falling very slowly. to recognize the presence of dust in air there are two principal tests; the first is, the obvious one of looking at it with plenty of light, the way one is accustomed to look for anything else; the other is a method of mr. john aitken's, viz., to observe the condensation of water vapor. take these in order. when a sunbeam enters a darkened room through a chink, it is commonly said to be rendered visible by the motes or dust particles dancing in it; but of course really it is not the motes which make the sunbeam visible, but the sunbeam the motes. a dust particle is illuminated like any other solid screen, and is able to send a sufficient fraction of light to our eyes to render itself visible. if there are no such particles in the beam--nothing but clear, invisible air--then of course nothing is seen, and the beam plunges on its way quite invisible to us unless we place our eyes in its course. in other words, to be visible, light must enter the eye. (a concentrated beam was passed through an empty tube, and then ordinary air let in.) the other test, that of mr. aitken, depends on the condensation of steam. when a jet of steam finds itself in dusty air, it condenses around each dust particle as a nucleus, and forms the white visible cloud popularly called steam. in the absence of nuclei mr. aitken has shown that the steam cannot condense until it is highly supersaturated, and that when it does it condenses straight into rain--that is, into large drops which fall. the condensation of steam is a more delicate test for dust than is a beam of light. a curious illustration of the action of nuclei in condensing moisture has just occurred to me, in the experiment--well known to children--of writing on a reasonably clean window-pane with, say, a blunt wooden point, and then breathing on the glass; the condensation of the breath renders the writing legible. no doubt the nuclei are partially wiped away by the writing, and the moisture will condense into larger drops with less light-scattering power along the written lines than over the general surface of the pane where the nuclei are plentiful, and the drops therefore numerous and minute. mr. aitken points out that if the air were ever quite dustless, vapor could not condense, but the air would gradually get into a horribly supersaturated condition, soaking all our walls and clothes, dripping from every leaf, and penetrating everywhere, instead of falling in an honest shower, against which umbrellas and slate roofs are some protection. but let us understand what sort of dust it is which is necessary for this condensing process. it is not the dust and smoke of towns, it is not the dust of a country road; all such particles as these are gross and large compared with those which are able to act as condensers of moisture. the fine dust of mr. aitken exists everywhere, even in the upper regions of the atmosphere; many of its particles are of ultra-microscopic fineness, one of them must exist in every raindrop, nay, even in every spherule of a mist or cloud, but it is only occasionally that one can find them with the microscope. it is to such particles as these that we owe the blue of the sky, and yet they are sufficiently gross and tangible to be capable of being filtered out of the air by a packed mass of cotton-wool. such dust as this, then, we need never be afraid of being without. without it there could be no rain, and existence would be insupportable, perhaps impossible; but it is not manufactured in towns; the sea makes it; trees and wind make it; but the kind of dust made in towns rises only a few hundred yards or so into the atmosphere, floating as a canopy or pall over those unfortunate regions, and sinks and settles most of it as soon as the air is quiet, but scarcely any of it ever rises into the upper regions of the atmosphere at all. dust, then, being so universally prevalent, what do i mean by dust-free spaces? how are such things possible? and where are they to be found? in dr. tyndall was examining dusty air by means of a beam of light in which a spirit-lamp happened to be burning, when he noticed that from the flame there poured up torrents of apparently thick black smoke. he could not think the flame was really smoky, but to make sure he tried, first a bunsen gas flame and then a hydrogen flame. they all showed the same effect, and smoke was out of the question. he then used a red-hot poker, a platinum wire ignited by an electric current, and ultimately a flask of hot water, and he found that from all warm bodies examined in dusty air by a beam of light the upstreaming convection currents were dark. now, of course smoke would behave very differently. dusty air itself is only a kind of smoke, and it looks bright, and the thicker the smoke the brighter it looks; the blackness is simply the utter absence of smoke; there is nothing at all for the light to illuminate, accordingly we have the blankness of sheer invisibility. here is a flame burning under the beam, and, to show what real smoke looks like, i will burn also this spirit lamp filled with turpentine instead of alcohol. _why_ the convention currents were free from dust was unknown; tyndall thought the dust was burnt and consumed; dr. frankland thought it was simply evaporated. in lord rayleigh took the matter up, not feeling satisfied with these explanations, and repeated the experiment very carefully. he noted several new points, and hit on the capital idea of seeing what a cold body did. from the cold body the descending current was just as dark and dust-free as from a warm body. combustion and evaporation explanations suffered their death-blow. but he was unable to suggest any other explanation in their room, and so the phenomenon remained curious and unexplained. in this state mr. clark and i took the matter up last summer, and critically examined all sorts of hypotheses that suggested themselves, mr. clark following up the phenomena experimentally with great ingenuity and perseverance. one hypothesis after another suggested itself, seemed hopeful for a time, but ultimately had to be discarded. some died quickly, others lingered long. in the examination of one electrical hypothesis which suggested itself we came across various curious phenomena which we hope still to follow up.[ ] it was some months before what we now believe to be the true explanation began to dawn upon us. meanwhile we had acquired various new facts, and first and foremost we found that the dark plane rising from a warm body was only the upstreaming portion of a dust-free _coat_ perpetually being renewed on the surface of the body. let me describe the appearance and mode of seeing it by help of a diagram. (for full description see _philosophical magazine_ for march, .) [footnote : for instance, the electric properties of crystals can be readily examined in illuminated dusty air; the dust grows on them in little bushes and marks out their poles and neutral regions, without any need for an electrometer. magnesia smoke answers capitally.] surrounding all bodies warmer than the air is a thin region free from dust, which shows itself as a dark space when examined by looking along a cylinder illuminated transversely, and with a dark background. at high temperatures the coat is thick; at very low temperatures it is absent, and dust then rapidly collects on the rod. on a warm surface only the heavy particles are able to settle--there is evidently some action tending to drive small bodies away. an excess of temperature of a degree or two is sufficient to establish this dust-free coat, and it is easy to see the dust-free plane rising from it. the appearances may also be examined by looking along a cylinder _toward_ the source of light, when the dust-free spaces will appear brighter than the rest. a rod of electric light carbon warmed and fixed horizontally across a bell-jar full of dense smoke is very suitable for this experiment, and by means of a lens the dust-free regions may be thus projected on to a screen. diminished pressure makes the coat thicker. increased pressure makes it thinner. in hydrogen it is thicker, and in carbonic acid thinner, than in air. we have also succeeded in observing it in liquids--for instance, in water holding fine rouge in suspension, the solid body being a metal steam tube. quantitative determinations are now in progress. [illustration: fig. and fig. ] fig. shows the appearance when looking along a copper or carbon rod laterally illuminated; the paths of the dust particles are roughly indicated. fig. shows the coat on a semi-cylinder of sheet copper with the concave side turned toward the light. it is difficult to give the full explanation of the dust free spaces in a few words, but we may say roughly that there is a molecular bombardment from all warm surfaces by means of which small suspended bodies get driven outward and kept away from the surface. it is a sort of differential bombardment of the gas molecules on the two faces of a dust particle somewhat analogous to the action on mr. crookes' radiometer vanes. near cold surfaces the bombardment is very feeble, and if they are cold enough it appears to act toward the body, driving the dust inward--at any rate, there is no outward bombardment sufficient to keep the dust away, and bodies colder than the atmosphere surrounding them soon get dusty. thus if i hold this piece of glass in a magnesium flame, or in a turpentine or camphor flame, it quickly gets covered with smoke--white in the one case, black in the other. i take two conical flasks with their surfaces blackened with camphor black, and filling one with ice, the other with boiling water, i cork them and put a bell jar over them, under which i burn some magnesium wire; in a quarter of an hour or so we find that the cold one is white and hoary, the hot one has only a few larger specks of dust on it, these being of such size that the bombardment was unable to sustain their weight, and they have settled by gravitation. we thus see that when the air in a room is warmer than the solids in it--as will be the case when stoves, gas-burners, etc., are used--things will get very dusty; whereas when walls and objects are warmer than the air--as will be the case in sunshine, or when open fireplaces are used, things will tend to keep themselves more free from dust. mr. aitken points out that soot in a chimney is an illustration of this kind of deposition of dust; and as another illustration it strikes me as just possible that the dirtiness of snow during a thaw may be partly due to the bombardment on to the cold surface of dust out of the warmer air above. mr. aitken has indeed suggested a sort of practical dust or smoke filter on this principle, passing air between two surfaces--one hot and one cold--so as to vigorously bombard the particles on to the cold surface and leave the air free. but we have found another and apparently much more effectual mode of clearing air than this. we do it by discharging electricity into it. it is easily possible to electrify air by means of a point or flame, and an electrified body has this curious property, that the dust near it at once aggregates together into larger particles. it is not difficult to understand why this happens; each of the particles becomes polarized by induction, and they then cling together end to end, just like iron filings near a magnet. a feeble charge is often sufficient to start this coagulating action. and when the particles have grown into big ones, they easily and quickly fall. a stronger charge forcibly drives them on to all electrified surfaces, where they cling. a fine water fog in a bell jar, electrified, turns first into a coarse fog or scotch mist, and then into rain. smoke also has its particles coagulated, and a space can thus be cleared of it. i will illustrate this action by making some artificial fogs in a bell-jar furnished with a metal point. first burn some magnesium wire, electrify it by a few turns of this small voss machine, and the smoke has become snow; the particles are elongated, and by pointing to the charged rod indicate the lines of electrostatic force very beautifully; electrify further, and the air is perfectly clear. next burn turpentine, and electrify gently; the dense black smoke coagulates into black masses over an inch long; electrify further, and the glass is covered with soot, but the air is clear. turpentine smoke acts very well, and can be tried on a larger scale; a room filled with turpentine smoke, so dense that a gas-light is invisible inside it, begins to clear in a minute or two after the machine begins to turn, and in a quarter of an hour one can go in and find the walls thickly covered with stringy blacks, notably on the gas-pipes and everything most easily charged by induction. next fill a bell-jar full of steam, and electrify, paying attention to insulation of the supply point in this case. in a few seconds the air looks clear, and turning on a beam of light we see the globules of water dancing about, no longer fine and impalpable, but separately visible and rapidly falling. finally, make a london fog by burning turpentine and sulphur, adding a little sulphuric acid, either directly as vapor or indirectly by a trace of nitric oxide, and then blowing in steam. electrify, and it soon becomes clear, although it lakes a little longer than before; and on removing the bell-jar we find that even the smell of so has disappeared, and only a little vapor of turpentine remains. similarly we can make a widnes fog by sulphureted hydrogen, chlorine, sulphuric acid, and a little steam. probably the steam assists the clearing when gases have to be dealt with. it may be possible to clear the air of tunnels by simply discharging electricity into the air--the electricity being supplied by holtz machines, driven say by small turbines--a very handy form of power, difficult to get out of order. or possibly some hydro-electric arrangement might be devised for the locomotive steam to do the work. i even hope to make some impression on a london fog, discharging from lightning conductors or captive balloons carrying flames, but it is premature to say anything about this matter yet. i have, however, cleared a room of smoke very quickly with a small hand machine. it will naturally strike you how closely allied these phenomena must be to the fact of popular science that "thunder clears the air." ozone is undoubtedly generated by the flashes, and may have a beneficial effect, but the dust-coagulating and dust-expelling power of the electricity has a much more rapid effect, though it may not act till the cloud is discharged. consider a cloud electrified slightly; the mists and clouds in its vicinity begin to coagulate, and go on till large drops are formed, which may be held up by electrical action, the drops dancing from one cloud to another and thus forming the very dense thunder cloud. the coagulation of charged drops increases the potential, as prof. tait points out, until at length--flash--the cloud is discharged, and the large drops fall in a violent shower. moreover, the rapid excursion to and fro of the drops may easily have caused them to evaporate so fast as to freeze, and hence we may get hail. while the cloud was electrified, it acted inductively on the earth underneath, drawing up an opposite charge from all points, and thus electrifying the atmosphere. when the discharge occurs this atmospheric electrification engages with the earth, clearing the air between, and driving the dust and germs on to all exposed surfaces. in some such way also it may be that "thunder turns milk sour," and exerts other putrefactive influences on the bodies which receive the germs and dust from the air. but we are now no longer on safe and thoroughly explored territory. i have allowed myself to found upon a basis of experimental fact, a superstructure of practical application to the explanation of the phenomena of nature and to the uses of man. the basis seems to me strong enough to bear most of the superstructure, but before being sure it will be necessary actually to put the methods into operation and to experiment on a very large scale. i hope to do this when i can get to a suitable place of operation. liverpool fogs are poor affairs, and not worth clearing off. manchester fogs are much better and more frequent, but there is nothing to beat the real article as found in london, and in london if possible i intend to rig up some large machines and to see what happens. the underground railway also offers its suffocating murkiness as a most tempting field for experiment, and i wish i were able already to tell you the actual result instead of being only in a position to indicate possibilities. whether anything comes of it practically or not, it is an instructive example of how the smallest and most unpromising beginnings may, if only followed up long enough, lead to suggestions for large practical application. when we began the investigation into the dust-free spaces found above warm bodies, we were not only without expectation, but without hope or idea of any sort, that anything was likely to come of it; the phenomenon itself possessed its own interest and charm. and so it must ever be. the devotee of pure science never has practical developments as his primary aim; often he not only does not know, but does not in the least care whether his researches will ever lead to any beneficial result. in some minds this passive ignoring of the practical goes so far as to become active repulsion; so that some singularly biased minds will not engage in anything which seems likely to lead to practical use. i regard this as an error, and as the sign of a warped judgment, for after all man is to us the most important part of nature; but the system works well nevertheless, and the division of labor accomplishes its object. one man investigates nature impelled simply by his own genius, and because he feels he cannot help it; it never occurs to him to give a reason for or to justify his pursuits. another subsequently utilizes his results, and applies them to the benefit of the race. meanwhile, however, it may happen that the yet unapplied and unfruitful results evoke a sneer, and the question: "cui bono?" the only answer to which question seems to be: "no one is wise enough to tell beforehand what gigantic developments may not spring from the most insignificant fact." * * * * * telephony and telegraphy on the same wires simultaneously. for the last eighteen months a system has been in active operation in belgium whereby the ordinary telegraph wires are used to convey telephonic communications at the same time that they are being employed in their ordinary work of transmitting telegraphic messages. this system, the invention of m. van rysselberghe, whose previous devices for diminishing the evil effects of induction in the telephone service will be remembered, has lately been described in the _journal telegraphique_ of berne, by m.j. banneux of the belgian telegraph department. our information is derived from this article and from others by m. hospitalier. the method previously adopted by van rysselberghe, to prevent induction from taking place between the telegraph wires and those running parallel to them used for telephone work, was briefly as follows: the system of sending the dots and dashes of the code--usually done by depressing and raising a key which suddenly turns on the current and then suddenly turns it off--was modified so that the current should rise gradually and fall gradually in its strength by the introduction of suitable resistances. these were introduced into the circuit at the moment of closing or opening by a simple automatic arrangement worked exactly as before by a key. the result, of the gradual opening and gradual closing of the circuit was that the current attained its full strength gradually instead of suddenly, and died away also gradually. and as induction from one wire to another depends not on the strength of the current, but on the rate at which the strength changes, this very simple modification had the effect of suppressing induction. later van rysselberghe changed these arrangements for the still simpler device of introducing permanently into the circuit either condensers or else electro-magnets having a high coefficient of self-induction. these, as is well known to all telegraphic engineers, retard the rise or fall of an electric current; they fulfill the conditions required for the working of van rysselberghe's method better than any other device. having got thus far in his devices for destroying induction from one line to another, van rysselberghe saw that, as an immediate consequence, it might be concluded that, if the telegraph currents were thus modified and graduated so that they produced no induction in a neighboring telephone line, they would produce no sound in the telephone if that instrument were itself joined up in the telegraph line. and such was found to be case. why this is so will be more readily comprehended if it be remembered that a telephone is sensitive to the changes in the strength of the current if those changes occur with a frequency of some hundreds or in some cases thousands of times _per second_. on the other hand, currents vibrating with such rapidity as this are utterly incompetent to affect the moving parts of telegraphic instruments, which cannot at the most be worked so as to give more than to separate signals _per minute_. [illustration: fig. ] [illustration: fig. ] the simplest arrangement for carrying out this method is shown in fig. , which illustrates the arrangements at one end of a line. m is the morse key for sending messages, and is shown as in its position of rest for receiving. the currents arriving from the line pass first through a "graduating" electromagnet, e , of about ohms resistance, then through the key, thence through the electromagnet, r, of the receiving morse instrument, and so to the earth. a condenser, c, of microfarads capacity is also introduced between the key and earth. there is a second "graduating" electromagnet, e , of ohms resistance introduced between the sending battery, b, and the key. when the key, m, is depressed in order to send a signal, the current from the battery must charge the condenser, c, and must magnetize the cores of the two electromagnets, e and e , and is thereby retarded in rising to its full strength. consequently no sound is heard in a telephone, t, inserted in the line-circuit. neither the currents which start from one end nor those which start from the other will affect the telephones inserted in the line. and, if these currents do not affect telephones in the actual line, it is clear that they will not affect telephones in neighboring lines. also the telephones so inserted in the main line might be used for speaking to one another, though the arrangement of the telephones in the same actual line would be inconvenient. accordingly m. van rysselberghe has devised a further modification in which a separate branch taken from the telegraph line is made available for the telephone service. to understand this matter, one other fact must be explained. telephonic conversation can be carried on, even though the actual metallic communication be severed by the insertion of a condenser. indeed, in quite the early days of the bell telephone, an operator in the states used a condenser in the telegraph line to enable him to talk through the wire. if a telephonic set at t (fig. ) communicate through the line to a distant station, t , through a condenser, c, of a capacity of half a microfarad, conversation is still perfectly audible, provided the telephonic system is one that acts by induction currents. and since in this case the interposition of the condenser prevents any continuous flow of current through the line, no perceptible weakening will be felt if a shunt s, of as high a resistance as ohms and of great electromagnetic rigidity, that is to say, having a high coefficient of self-induction, be placed across the circuit from line to earth. in this, as well as in the other figures, the telephones indicated are of the bell pattern, and if set up as shown in fig. , without any battery, would be used both as transmitter and receiver on bell's original plan. but as a matter of fact any ordinary telephone might be used. in practice the bell telephone is not advantageous as a transmitter, and has been abandoned except for receiving; the blake, ader, or some other modification of the microphone being used in conjunction with a separate battery. to avoid complication in the drawings, however, the simplest case is taken. and it must be understood that instead of the single instrument shown at t or t , a complete set of telephonic instruments, including transmitter, battery, induction-coil, and receiver or receivers, may be substituted. and if a shunt, s, of ohms placed across the circuit makes no difference to the talking in the telephones because of the interposition of the separating condenser, c, it will readily be understood that a telegraphic system properly "graduated," and having also a resistance of ohms, will not affect the telephones if interposed in the place of s. this arrangement is shown in fig. , where the "graduated" telegraph-set from fig. is intercalated into the telephonic system of fig. , so that both work simultaneously, but independently, through a single line. the combined system at each end of the line will then consist of the telephone-set, t , the telegraph instruments (comprising battery, b , key, m and morse receiver, r ), the "graduating" electromagnets, e , and e , the "graduating" condenser, c , and the "separating" condenser, c . it was found by actual experiments that the same arrangement was good for lines varying from to miles in length. a single wire between brussels, ghent, and ostend is now regularly employed for transmission by telegraph of the ordinary messages and of the telemeteorographic signals between the two observatories at those places, and by telephone of verbal simultaneous correspondence, for one of the ghent newspapers. a still more interesting arrangement is possible, and is indicated in fig. . here a separating condenser is introduced at the intermediate station at ghent between earth and the line, which is thereby cut into two independent sections for telephonic purposes, while remaining for telegraphic purposes a single undivided line between brussels and ostend. brussels can telegraph to ostend, or ostend to brussels, and at the same time the wire can be used to telephone between ghent and ostend, or between ghent and brussels, or both sections may be simultaneously used. [illustration: fig. ] [illustration: fig. ] it would appear, then, that m. van rysselberghe has made an advance of very extraordinary merit in devising these combinations. we have seen in recent years how duplex telegraphy superseded single working, only to be in turn superseded by the quadruplex system. multiplex telegraphy of various kinds has been actively pursued, but chiefly on the other side of the atlantic rather than in this country, where our fast-speed automatic system has proved quite adequate hitherto. whether we shall see the adoption in the united kingdom of van rysselberghe's system is, however, by no means certain. the essence of it consists in retarding the telegraphic signals to a degree quite incompatible with the fast-speed automatic transmission of telegraphic messages in which our post office system excels. we are not likely to spoil our telegraphic system for the sake of simultaneous telephony, unless there is something to be gained of much greater advantage than as yet appears.--_nature._ * * * * * the electric marigraph. for registering the height of the tide at every instant, hydrographic services generally adopt quite a simple marigraph. the apparatus consists in principle of a counterpoised float whose rising and falling motion, reduced to a tenth, by means of a system of toothed wheels, is transmitted to a pencil which moves in front of a vertical cylinder. this cylinder itself moves around its axis by means of a clockwork mechanism, and accomplishes one entire revolution every twenty-four hours. by this means is obtained a curve of the tide in which the times are taken for abscisses and the heights of the sea for ordinates. however little such marigraphs have had to be used, great defects have been recognized in them. when we come to change the sheet on the cylinder (and such change should be made at least once every fifteen days), there is an interruption in the curve. it is necessary, besides, to perform office work of the most detailed kind in order to refer to the same origin all these curves, which are intercrossed and often superposed in certain parts upon the original sheet. in order to render such a disentanglement possible, it is indispensable to mark by hand, at least once every twenty-four hours, upon each curve, the date of the day corresponding to it. it is equally useful to verify the exactness of the indications given by the apparatus by making readings several times a day on a scale of tides placed alongside of the float. nine times out of ten the rise of the waves renders such readings very difficult and the control absolutely illusory. all these conditions united, as well as others that we neglect in this brief discussion, necessitate a surveillance at every instant. the result is that these marigraphs must be installed in a special structure, very near the bank, so as to be reachable at all times, and that the indications that they give are always vitiated by error, since the operation is performed upon a level at which are exerted disturbing influences that are not found at a kilometer at sea. it were to be desired that the float could be isolated by placing it a certain distance from the shore, and transmit its indications, by meant of a play of currents, to a registering apparatus situated upon _terra firma_. in the course of one of his lectures published in the december number ( ) of the _elektrotechnische zeitschrift_, mr. von hefner-alteneck tells us that such a desideratum has been supplied by the firm of siemens & halske. this marigraph, constructed on an order of the german admiralty, gives the level of the sea every ten minutes with an approximation of . per cent., and that too for a difference of meters between the highest and lowest sea. the apparatus consists, as we said above, of a float and registering device, connected with each other by means of a cable. this latter is formed of three ordinary conductors covered with gutta percha and surrounded with a leaden sheath, which latter is itself protected against accident by means of a strong covering of iron wire and hemp. the return is effected through the earth. we shall enter into details concerning each of these two apparatus in-succession, by beginning with the float, of which fig. gives a general view, and fig. a diagrammatic sketch. the float moves in a cast iron cylinder, having at its lower part a large number of apertures of small diameter, so that the motion of the waves does not perceptibly influence the level of the water in the interior of the cylinder. it is attached to a copper ribbon, b, whose other extremity is fixed to the drum, t. the ribbon winds around the latter in the rising motion of the float, owing to a spiral spring arranged so as to act upon the drum. the tension of this spring goes on increasing in measure as the float descends. [illustration: fig. .--float of siemens and halske's marigraph.] [illustration: fig. .] this difference in tension is utilized for balancing at every instant the weight of the ribbon unwound, and thus causing the float to immerse itself in the water to a constant degree. the ribbon, b, is provided throughout its length with equidistant apertures that exactly correspond to tappets that project from the circumference of the wheel, r. when the float moves its position, the wheel, r, begins to turn and carries along in doing so the pinion, w, which revolves over the toothed wheels, s , s , and s . the thickness of w is equal to that of the three wheels, s , s , and s , and a special spring secures at every instant an intimate contact between the pinion and the said wheels. these latter are insulated from each other and from the axle upon which they are keyed, and communicate, each of them, with conductors, i., ii., and iii. they are so formed and mounted that, in each of them, the tooth in one corresponds to the interspace in the two others. as a result of this, in the motion of the pinion, w, the latter is never in contact with but one of the three wheels, s , s , and s . if we add that the lines, i., ii., and iii. are united at the shore station with one of the poles of a pile whose other pole is connected with the earth, and that w communicates with the earth through the intermedium of r, and the body of the apparatus, it is easy to see that in a vertical motion of the float in one direction we shall have currents succeeding each other in the order i., ii., iii., i., ii., etc., while the order will become iii., ii., i., iii., ii., etc., if the direction of the float's motion happen to change. [illustration: fig. .] [illustration: fig. .] in order to understand how a variation in currents of this kind can be applied in general for producing a rotary motion in the two directions, it will only be necessary to refer to figs. and . the conductors, l , l , and l communicate with the bobbins of three electromagnets, e , e , and e , whose poles are bent at right angles to the circumference of the wheel, r. there is never but one pole opposite a tooth. the distance between two consecutive poles must be equal to a multiple of the pitch increased (fig. ) or diminished (fig. ) by one-third thereof. it will be seen upon a simple inspection of the figures that r will revolve in the direction of the hands of a watch when the currents follow the order l , l , l , etc., in the case shown in fig. , while in the case shown in fig. the rotary motion will be in the contrary direction for this same order of currents. but, in both cases, and this is the important point, the direction of rotation changes when the order in the succession of currents; is inverted. fig. gives a perspective view of the registering apparatus, and fig. represents it in diagram. it will be at once seen that, the toothed wheel, r, is reduced to its simplest expression, since it consists of two teeth only. the electro-magnets are arranged at an angle of °, and for a change of current the wheel, r, describes an angle of °, that is to say, a sixth of a circumference. the motion of r is transmitted, by means of the pinion, d, and the wheel, e, to the wheel, t. for a one-meter variation in level the wheel, t, makes one complete revolution. it is divided into equal parts, and each arc therefore corresponds to a difference of one centimeter in the level, and carries, engraved in projection, the corresponding number. as a consequence, there is upon the entire circumference a series of numbers from to . the axle upon which the wheel, t, is keyed is prolonged, on the side opposite e, by a threaded part, a, which actuates a stylet, g. this latter is held above by a rod, i, which is connected with a fork movable around a vertical axis, shown in fig. . the rectilinear motion of g is mm. for a variation of one meter in level. its total travel is consequently mm. the sheet of paper upon which the indications are taken, and which is shown of actual size in fig. , winds around the drum, p, and receives its motion from the cylinder, w. this sheet is covered throughout its length with fine prepared paper that permits of taking the imprints by impression. [illustration: fig. ] [illustration: fig. --receiver of siemens and halske's marigraph.] [illustration: fig. ] this stated, the play of the apparatus may be easily understood. every ten minutes a regulating clock closes the circuit of the local pile, b , and establishes a contact at c. the electro-magnet, e , attracts its armature, and thus acts upon the lever, h, which presses the sheet of paper against the stylet in front that serves to mark the level of the lowest waters, and against the stylet, g, and the wheels, t and z. in falling back, the lever, h, causes the advance, by one notch, of the ratchet wheel that is mounted at the extremity of the cylinder w, and thus displaces the sheet of paper a distance of mm. the wheel, z, carries engraved in projection upon its circumference the hours in roman figures, and moves forward one division every minutes. the motion of this wheel is likewise controlled by the cylinder, w. it will be seen upon referring to fig. , that there is obtained a very sharp curve marked by points. we have a general view on considering the curve itself, and the height in meters is read directly. the fractions of a meter, as well as the times, are in the margin. thus, at the point, a, the apparatus gives at o'clock and minutes a height of tide of . m. above the level of the lowest water. this apparatus might possibly operate well, and yet not be in accord with the real indications of the float, so it has been judged necessary to add to it the following control. every time the float reaches meters above the level of the lowest tide, the circuit of one of the lines that is open at this moment (that of line i, for example) closes at c (fig. ), into this new circuit there is interposed a considerable resistance, w, so that the energy of the current is weakened to such a point that it in nowise influences the normal travel of the wheel, r. at the shore station, there is placed in deviation a galvanoscope, k, whose needle is deflected. it suffices, then, to take datum points upon the registering apparatus, upon the wheel, t, and the screw, a, in such a way as to ascertain the moment at which the stylet, g, is going to mark meters. at this moment the circuit of the galvanoscope, k, is closed, and we ascertain whether there is a deviation of the needle. as the sea generally rises to the height of meters twice a day, it is possible to control the apparatus twice a day, and this is fully sufficient. it always belongs to practice to judge of an invention. mr. von hefner-alteneck tells us that two of these apparatus have been set up--one of them a year ago in the port of kiel, and the other more recently at the isle of wangeroog in the north sea--and that both have behaved excellently since the very first day of their installation. we shall add nothing to this, since it is evidently the best eulogium that can be accorded them.--_la lumiere electrique._ * * * * * delune & co.'s system of laying underground cables. in recent times considerable attention has been paid to the subject of laying telegraph cables underground, and various methods have been devised. in some cases the cables have been covered with an armor of iron, and in others they have been inclosed in cast-iron pipes. for telephonic service they are generally inclosed in leaden tubes. what this external envelope shall be that is to protect the wires from injury is a question of the highest importance, since not only the subject of protection is concerned, but also that of cost. it is therefore interesting to note the efforts that are being made in this line of electric industry. [illustration: fig. . section of the pipe open.] [illustration: fig. . section of the pipe closed.] messrs. delune & co. have recently taken out a patent for an arrangement consisting of pipes made of beton. the annexed cuts, borrowed from _l'electricite_, represent this new system. the pipes, which are provided with a longitudinal opening, are placed end to end and coupled with a cement sleeve. the cables are put in place by simply unwinding them as the work proceeds, and thus all that traction is done away with that they are submitted to when cast iron pipes are used. when once the cables are in place the longitudinal opening is stopped up with cement mortar, and in this way a very tight conduit is obtained whose hardness increases with time. the value of the system therefore depends, as in all cement work, on the care with which the manufacturing is done. experiments have been made with the system at toulouse, by the minister of post offices and telegraphs, and at lyons, by the general society of telephones. here, as with all similar questions, no opinion can be pronounced until after a prolonged experience. but we cannot help setting forth the advantages that the system offers. these are, in the first place, a saving of about per cent. over iron pipe, and in the second, a better insulation, and consequently a better protection of the currents against all kinds of disturbance, since a non-conducting mass of cement is here substituted for metal. * * * * * electricity applied to horse-shoeing. "there is nothing new but what has been forgotten," said marie antoinette to her milliner, mdlle. bertin, and what is true of fashion is also somewhat so of science. shoeing restive horses by the aid of electricity is not new, experiments thereon having been performed as long ago as by mr. defoy, who operated with a small magneto machine. but the two photographs reproduced in figs. and have appeared to us curious enough to be submitted to our readers, as illustrating mr. defoy's method of operating with an unruly animal. [illustration: fig. .--the horse receiving the current.] the battery used was a small grenet bichromate of potash pile, which was easy to graduate on account of the depth to which the zinc could be immersed. this pile was connected with the inductor of a small ruhmkorff coil, whose armature was connected with a snaffle-bit placed in the horse's mouth. [illustration: fig. .--the horse conquered.] this bit was arranged as follows (fig. ): the two conductors, which were uncovered for a length of about three centimeters at their extremity, were placed opposite each other on the two joints of the snaffle, and about five or six centimeters apart. the mouth-pieces of the bit had previously been inclosed in a piece of rubber tubing, in order to insulate the extremities of the conductors and permit the recomposition of the current to take place through the animal's tongue or palate. each of the bare ends of the conductors was provided, under a circular brass ligature, with a small damp sponge, which, surrounding the mouth-piece, secured a perfect contact of each end of the circuit with the horse's mouth. [illustration: fig. .--arrangement of the bit] the horse having been led in, defended himself vigorously as long as an endeavor was made to remove his shoes by the ordinary method, but the current had acted scarcely fifteen seconds when it became possible to lift his feet and strike his shoes with the hammer. the experimenter having taken care during this experiment to place the bobbin quite near the horse's ear, so that he could hear the humming of the interrupter, undertook a second experiment in the following way: having detached the conductors from the armature, he placed himself in front of the horse (as shown in fig. ), and began to imitate the humming sound of the interrupter with his mouth. the animal at once assumed the stupefied position that the action of the current gave him in the first experiment, and allowed his feet to be lifted and shod without his even being held by the snaffle. the horse was for ever after subdued, and yet his viciousness and his repugnance to shoeing were such that he could only be shod previously by confining his legs with a kicking-strap. it should be noted that the action of the induction coil, mounted as this was, was very feeble and not very painful; and yet it was very disagreeable in the mouth, and gave in this case a shock with a sensation of light before the eyes, as we have found by experimenting upon ourselves. from our own most recent experiments, we have ascertained the following facts, which may guide every horse-owner in the application of electricity to an animal that is opposed to being shod: ( ) to a horse that defends himself because he is irritable by temperament, and nervous and impressionable (as happens with animals of pure or nearly pure blood), the shock must be administered feebly and gradually before an endeavor is made to take hold of his leg. the horse will then make a jump, and try to roll over. the jump must be followed, while an assistant holds the bridle, and the action of the current must be at once arrested. after this the horse will not endeavor to defend himself, and his leg may be easily handled. ( ) certain large, heavy, naturally ugly horses kick through sheer viciousness. in this case, while the current is being given it should be gradually increased in intensity, and the horse's foot must be seized during its action. in most cases the passage of a current through such horses (whose mucous membrane is less sensitive) produces only a slightly stupefied and contracted position of the head, accompanied with a slight tremor. the current must be shut off as soon as the horse's foot is well in one's hand, and be at once renewed if he endeavors to defend himself again, as is rarely the case. it is a mare of this nature that is represented in the annexed figures. we know that this same system has been applied for bringing to an abrupt standstill runaway horses, harnessed to vehicles; but knowing the effect of a sudden stoppage under such circumstances, we believe that the remedy would prove worse than the disease, since the coachman and vehicle, in obedience to the laws of inertia, would continue their motion and pass over the animals, much to their detriment.--_science et nature._ * * * * * esteve's automatic pile. mr. esteve has recently devised a generator of electricity which he claims to be energetic, constant, and always ready to operate. the apparatus is designed for the production of light and for actuating electric motors, large induction bobbins, etc. we give a description of it herewith from data communicated by its inventor. the accompanying cut represents a battery of elements, with a reservoir, r, for the liquid, provided at its lower part with a cock for allowing the liquid to enter the pile. the vessels of the different elements are of rectangular form. at the upper part, and in the wider surfaces of each, there are two tubes. the first tube of the first vessel receives the extremity of a safety-tube, a, whose other extremity enters the upper part of the reservoir, r. this tube is designed for regulating the flow of the liquid into the pile. when the cock, r, is too widely open, the liquid might have a tendency to flow over the edges of the vessel; but this would close the orifice of the tube, a, and, as the air would then no longer enter the reservoir, r, the flow would be stopped automatically. the second tube of the first vessel is connected with a lead tube, , one of the extremities of which enters the second vessel. the other tubes are arranged in the same way in the other vessels. the renewal of the liquids is effected by displacement, in flowing upward from one element over into another; and the liquids make their exit from the pile at d, after having served six times. the electrodes of the two first elements are represented as renewed in the cut, in order to show the arrangement of the tubes. [illustration: esteve's automatic pile.] _dimensions._--the zinc, , has a superficies of × centimeters, and is cut out of the ordinary commercial sheet metal. it may be turned upside down when one end has become worn away, thus permitting of its being entirely utilized. the negative electrode is formed of four carbons, which have, each of them, a superficies of × centimeters. these four carbons are less fragile and are more easily handled than two having the same surface. their arrangement is shown at the left of the figure. they are fixed to a strip of copper, a, to which is soldered another strip, l, bent at right angles. there are thus two pairs of carbon per element, and these are simply suspended from a piece of wood, as shown in the figure. upon this wooden holder will be seen the two strips, ll, that are designed to be put in contact with the zinc of the succeeding element by means of pinchers that connect the electrodes with one another. this arrangement permits the pile to be taken apart very quickly. _charging, work, and duration of the pile._--the inventor has made a large number of experiments with solutions of bichromate of potash of various degrees of saturation, and has found the following to give the best results: bichromate of potash. kilogramme. sulphuric acid liters. water " when a larger quantity of the salt is used, crystallization occurs in the pile. constants and work constants and work of an element of a round bunsen having a zinc of element, × cm. × cm. volts. . . resistance. . . work disposable in the external circuit. . k. . k. the work disposable in the external circuit is deduced from the formula: t = e²/( r × . ) it will be seen that an element thus charged gives as much energy as . large bunsen elements. the battery is charged with liters of solution, and is capable of furnishing for hours a current of amperes with a difference of potential of volts at the pile terminals. the work, according to the formula (ei)/g, equals . kilogram-meters; with a feebler resistance in the external circuit it is capable of producing a current of amperes for an hour and an half. in this case the resistance of the external circuit equals the interior resistance of the pile. upon immersing the electrodes in new liquid, and with no resistance in the external circuit, the current may reach amperes. on renewing the liquids during the operation of the pile, a current of amperes is kept up if about a liter of saturation per hour be allowed to pass into the battery. for five hours, then, only liters are used instead of the that are necessary when the liquid is not renewed while the pile is in action.--_la nature._ * * * * * woodward's diffusion motor. the energy produced by the phenomena of diffusion is exhibited in lecture courses by placing a bell glass filled with hydrogen over a porous vessel at whose base is fixed a glass tube that dips into water. the hydrogen, in diffusing, enters the porous vessel, increases the internal pressure, and a number of bubbles escapes from the tube. on withdrawing the bell glass of hydrogen, the latter becomes diffused externally, a lower pressure occurs in the porous vessel, and the level of the water rises. the arrangement devised by mr. c.j. woodward, and recently presented to the physical society of london, is an adaptation of this experiment to the production of an oscillating motion by alternations in the internal and external diffusion of the hydrogen. the apparatus, represented herewith, consists of a scale beam about three feet in length that supports at one end a scale pan and weights, and, at the other, a corked porous vessel that carries a glass tube, c, which dips into a vessel containing either water or methylic alcohol. three or four gas jets, one of which is shown at e, are arranged around the porous vessel, as close as possible, but in such a way as not to touch it during the oscillation of the beam. these gas jets communicate with a gasometer tilled with hydrogen, the bell of which is so charged as to furnish a jet of sufficient strength. experience will indicate the best place to give the gas jets, but, in general, it is well to locate them at near the center of the porous vessel when the beam is horizontal. [illustration] it is now easy to see how the device operates. when the hydrogen comes in presence of the porous vessel it becomes diffused therein, and the pressure exerted in the interior then produces an ascent. when the bottom of the porous vessel gets above the jets, the internal diffusion ceases and the hydrogen becomes diffused externally, the internal pressure diminishes, and the vessel descends. the vessel then comes opposite the jets of hydrogen and the same motion occurs again, and soon indefinitely. the work produced by this motor, which has purely a scientific interest, is very feeble, and much below that assigned to it by theory. in order to obtain a maximum, it would be necessary to completely surround the porous vessel each time with hydrogen, and afterward remove the jets to facilitate the access of air. all the mechanical arrangements employed for obtaining such a result have failed, because the friction introduced by the maneuvering parts also introduces a resistance greater than the motor can overcome. there is therefore a waste of energy due to the continuous flow of hydrogen; but the apparatus, for all that, constitutes none the less an original and interesting device.--_la nature._ * * * * * some relations of heat to voltaic and thermo-electric action of metals in electrolytes.[ ] [footnote : read before the royal society, nov., .] by g. gore, f.r.s., ll.d. the experiments described in this paper throw considerable light upon the real cause of the voltaic current. the results of them are contained in twenty tables; and by comparing them with each other, and also by means of additional experiments, the following general conclusions and chief facts were obtained. when metals in liquids are heated, they are more frequently rendered positive than negative in the proportion of about . to . ; and while the proportion in weak solutions was about . to . , in strong ones it was about . to . , and this accords with their thermo-electric behavior as metals alone. the thermo-electric order of metals in liquids was, with nearly every solution, whether strong or weak, widely different from the thermo-electric order of the same metals alone. a conclusion previously arrived at was also confirmed, viz., that the liquids in which the hot metal was thermo-electro-positive in the largest proportion of cases were those containing highly electro-positive bases, such as the alkali metals. the thermo-electric effect of _gradually_ heating a metal in a liquid was sometimes different from that of _suddenly_ heating it, and was occasionally attended by a reversal of the current. degree of strength of liquid greatly affected the thermo-electric order of metals. increase of strength usually and considerably increased the potential of metals thermo-electro-negative in liquids, and somewhat increased that of those positive in liquids. the electric potential of metals, thermo-electro-positive in weak liquids, was usually about . times, and in strong ones . times, as great as of those which were negative. the potential of the strongest thermo-electric couple, viz., that of aluminum in weak solution of sodic phosphate, was . volt for ° f. difference of temperature, or about times that of a bismuth and antimony couple. heating one of the metals, either the positive or negative, of a voltaic couple, usually increased their electric difference, making most metals more positive, and some more negative; while heating the second one also usually neutralized to a large extent the effect of heating the first one. the electrical effect of heating a voltaic couple is nearly wholly composed of the united effects of heating each of the two metals separately, but is not however exactly the same, because while in the former case the metals are dissimilar, and are heated to the same temperature, in the latter they are similar, but heated to different temperatures. also, when heating a voltaic pair, the heat is applied to two metals, both of which are previously electro-polar by contact with each other as well as by contact with the liquid; but when heating one junction of a metal and liquid couple, the metal has not been previously rendered electro-polar by contact with a different one, and is therefore in a somewhat different state. when a voltaic combination, in which the positive metal is thermo-negative, and the negative one is thermo-positive, is heated, the electric potential of the couple diminishes, notwithstanding that the internal resistance is decreased. magnesium in particular, also zinc and cadmium, were greatly depressed in electromotive force in electrolytes by elevation of temperature. reversals of position of two metals of a voltaic couple in the tension series by rise of temperature were chiefly due to one of the two metals increasing in electromotive force faster than the other, and in many cases to one metal increasing and the other decreasing in electromotive force, but only in a few cases was it a result of simultaneous but unequal diminution of potential of the two metals. with eighteen different voltaic couples, by rise of temperature from ° to ° f., the electromotive force in twelve cases was increased, and in six decreased, and the average proportions of increase for the eighteen instances was . volt for the ° f. of elevation. a great difference in chemical composition of the liquid was attended by a considerable change in the order of the volta-tension series, and the differences of such order in two similar liquids, such as solutions of hydric chloride and potassic chloride, were much greater than those produced in either of those liquids by a difference of ° f. of temperature. difference of strength of solution, like difference of composition or of temperature, altered the order of such series with nearly every liquid; and the amount of such alteration by an increase of four or five times in the strength of the liquid was rather less than that caused by a difference of ° f. of temperature. while also a variation of strength of liquid caused only a moderate amount of change of order in the volta-tension series, it produced more than three times that amount of change in the thermo-electric tension series. the usual effect of increasing the strength of the liquid upon the volta-electromotive force was to considerably increase it, but its effect upon the thermo-electro-motive force was to largely decrease it. the degree of potential of a metal and liquid thermo-couple was not always exactly the same at the same temperature during a rise as during a fall of temperature; this is analogous to the variations of melting and solidifying points of bodies under such conditions, and also to that of supersaturation of a liquid by a salt, and is probably due to some hinderance to change of molecular movement. the rate of ordinary chemical corrosion of each metal varied in every different liquid; in each solution also it differed with every different metal. the most chemically positive metals were usually the most quickly corroded, and the corrosion of each metal was usually the fastest with the most acid solutions. the rate of corrosion at any given temperature was dependent both upon the nature of the metal and upon that of the liquid, and was limited by the most feebly active of the two, usually the electrolyte. the order of rate of corrosion of metals also differed in every different liquid. the more dissimilar the chemical characters of two liquids, the more diverse usually was the order of rapidity of corrosion of a series of metals in them. the order of rate of simple corrosion in any of the liquids examined differed from that of chemico-electric and still more from that of thermo-electric tension. corrosion is not the cause of thermo-electric action of metals in liquids. out of fifty-eight cases of rise of temperature the rate of ordinary corrosion was increased in every instance except one, and that was only a feeble exception--the increase of corrosion from ° to ° f. with different metals was extremely variable, and was from . to . times. whether a metal increased or decreased in thermo-electromotive force by being heated, it increased in rapidity of corrosion. the proportions in which the most corroded metal was also the most thermo-electro-positive one was . per cent. in liquids at ° f., and . in the same liquids at ° f.; and the proportion in which it was the most chemico-electro-positive at f. was . per cent, and at ° f. . per cent. the proportion of cases therefore in which the most chemico-electro-negative metal was the most corroded one increased from . to . per cent, by a rise of temperature of ° f. comparison of these proportions shows that corrosion usually influenced in a greater degree chemico-electric rather than thermo-electric actions of metals in liquids. not only was the relative number of cases in which the volta-negative metal was the most corroded increased by rise of temperature, but also the average relative loss by corrosion of the negative to that of the positive one was increased from . to . . the explanation most consistent with all the various results and conclusions is a kinetic one: that metals and electrolytes are throughout their masses in a state of molecular vibration. that the molecules of those substances, being frictionless bodies in a frictionless medium, and their motion not being dissipated by conduction or radiation, continue incessantly in motion until some cause arises to prevent them. that each metal (or electrolyte), when unequally heated, has to a certain extent an unlike class of motions in its differently heated parts, and behaves in those parts somewhat like two metals (or electrolytes), and those unlike motions are enabled, through the intermediate conducting portion of the substance, to render those parts electro-polar. that every different metal and electrolyte has a different class of motions, and in consequence of this, they also, by contact alone with each other at the same temperature, become electro-polar. the molecular motion of each different substance also increases at a different rate by rise of temperature. this theory is equally in agreement with the chemico-electric results. in accordance with it, when in the case of a metal and an electrolyte, the two classes of motions are sufficiently unlike, chemical corrosion of the metal by the liquid takes place, and the voltaic current originated by inherent molecular motion, under the condition of contact, is maintained by the portions of motion lost by the metal and liquid during the act of uniting together. corrosion therefore is an effect of molecular motion, and is one of the modes by which that motion is converted into and produces electric current. in accordance with this theory, if we take a thermo-electric pair consisting of a non-corrodible metal and an electrolyte (the two being already electro-polar by mutual contact), and heat one of their points of contact, the molecular motions of the heated end of each substance at the junction are altered; and as thermo-electric energy in such combinations usually increases by rise of temperature, the metal and liquid, each singly, usually becomes more electro polar. in such a case the unequally heated metal behaves to some extent like two metals, and the unequally heated liquid like two liquids, and so the thermo-electric pair is like a feeble chemico-electric one of two metals in two liquids, but without corrosion of either metal. if the metal and liquid are each, when alone, thermo-electro-positive, and if, when in contact, the metal increases in positive condition faster than the liquid by being heated, the latter appears thermo-electro-negative, but if less rapidly than the liquid, the metal appears thermo-electro-negative. as also the proportion of cases is small in which metals that are positive in the ordinary thermo-electric series of metals only become negative in the metal and liquid ones (viz., only out of in weak solutions, and out of the same number in strong ones), we may conclude that the metals, more frequently than the liquids, have the greatest thermo-electric influence, and also that the relative largeness of the number of instances of thermo-electro-positive metals in the series of metals and liquids, as in the series of metals only, is partly a consequence of the circumstance that rise of temperature usually makes substances--metals in particular--electro-positive. these statements are also consistent with the view that the elementary substances lose a portion of their molecular activity when they unite to form acids or salts, and that electrolytes therefore have usually a less degree of molecular motion than the metals of which they are partly composed. the current from a thermo-couple of metal and liquid, therefore, may be viewed as the united result of difference of molecular motion, first, of the two junctions, and second, of the two heated (or cooled) substances; and in all cases, both of thermo- and chemico-electric action, the immediate true cause of the current is the original molecular vibrations of the substances, while contact is only a static permitting condition. also that while in the case of thermo-electric action the sustaining cause is molecular motion, supplied by an external source of heat, in the case of chemico-electric action it is the motion lost by the metal and liquid when chemically uniting together. the direction of the current in thermo-electric cases appears to depend upon which of the two substances composing a junction increases in molecular activity the fastest by rise of temperature, or decreases the most rapidly by cooling. * * * * * air refrigerating machine. [illustration: improved air refrigerating machine.] messrs. j. & e. hall, dartford, exhibit at the international health exhibition, london, in connection with a cold storage room, two sizes of ellis' patent air refrigerator, the larger one capable of delivering , cubic feet of cold air per hour, when running at a speed of revolutions per minute; and the smaller one , cubic feet of cold air per hour, at revolutions per minute. the special features in these machines are the arrangement of parts, by which great compactness is secured, and the adoption of flat slides for the compressor, instead of the ordinary beat valves, which permits of a high rate of revolution without the objectionable noise which is caused by clacks beating on their seats. the engraving shows the general arrangement of the apparatus. figs. to show details of the compression and expansion valves, which are ordinary flat slides, partly balanced, and held up to their faces by strong springs from behind. the steam, compression, and expansion cylinders are severally bolted to the end of a strong frame, which though attached to the cooler box does not form part of it, the object being to meet the strains between the cylinders and shaft in as direct a manner as possible without allowing them to act on the cooler casting. each cylinder is double acting, the pistons being coupled to the shaft by three connecting rods, the two outer ones working upon crank pins fixed to overhung disks, and the center one on a crank formed in the shaft. the slide valves for all the cylinders are driven from two weigh shafts, the main valve shaft being actuated by a follow crank, and the expansion and cut off valves from the crosshead pin of the compressor. the machines may be used either in the vertical position as exhibited, or may be fixed horizontally; and it is stated that the construction is such as to admit of speeds of and revolutions per minute respectively for the larger and smaller machines, under which conditions the delivery of cold air may be taken at about , and , cubic feet per hour. messrs. hall also make this class of refrigerator without the steam cylinder, and arranged to be driven by a belt from a gas engine or any existing motive power. * * * * * a gas radiator and heater. [illustration: fig. & fig. a gas radiator and heater.] there is now being introduced into germany a gas radiator and heater, the invention of herr wobbe. it consists, as will be seen in engraving above, of a series of vertical u-shaped pipes, of wrought iron, millimeters ( inches) in diameter. the two legs of the u are of unequal length; the longer being about feet, and the shorter feet (exclusive of the bend at the top). beneath the open end of the shorter leg of each pipe is placed a burner, attached to a horizontal gas-pipe, which turns upon an axis. the object of having this pipe rotate is to bring the burners into an inclined position--shown by the dotted lines in fig. --for lighting them. on turning them back to the vertical position, the heated products of combustion pass up the shorter tube and down the longer, where they enter a common receptacle, from which they pass into the chimney or out of doors. surrounding the pipes are plates of sheet iron, inclined at the angle shown in fig. . the object of the plates is to prevent the heated air of the room from passing up to the ceiling, and send it out into the room. to prevent any of the pipes acting as chimneys, and bringing the products of combustion back into the room, as well as to avoid any back-pressure, a damper is attached to the outlet receptacle. the heated gas becomes cooled so much (to about ° fahr.) that water is condensed and precipitated, and collects in the vessel below the outlet. each burner has a separate cock, by which it may be kept closed, half-open, or open. to obviate danger of explosion, there is a strip of sheet iron in front of the burners, which prevents their being lighted when in a vertical position; so that, in case any unburned gas gets into the pipes, it cannot be ignited, for the burners can only be lighted when inclined to the front. in starting the stove the burners are lighted, in the inclined position; the chain from the damper pulled up; the burners set vertical; and, as soon as they are all drawing well into the tubes, the damper is closed. if less heat is desired, the cocks are turned half off. it is not permissible to entirely extinguish some of the burners, unless the unused pipes are closed to prevent the products of combustion coming back into the room. the consumption of gas per burner, full open, with a pressure of / , is said to be only - / cubic feet per hour. * * * * * concrete water pipes. concrete water pipes of small diameter, according to a foreign contemporary, are used in parts of france, notably for water mains for the towns of coulommiers and aix-en-provence. the pipes were formed of concrete in the trench itself. the mould into which the concrete was stamped was sheet iron about two yards in length. the several pipes were not specially joined to each other, the joints being set with mortar. the concrete consisted of three parts of slow setting cement and three parts of river sand, mixed with five parts of limestone debris. the inner diameter of the pipes was nine inches; their thickness, three inches. the average fall is given at one in five hundred; the lowest speed of the current at one foot nine inches per second. to facilitate the cleaning of the pipes, man-holes are constructed every one hundred yards or so, the sides of which are also made of concrete. the trenches are about five feet deep. the work was done by four men, who laid down nearly two hundred feet of pipe in a working day; the cost was about ninety-three cents per running yard. it is claimed as an advantage for the new method that the pipes adhere closely to the inequalities of the trench, and thus lie firmly on the ground. when submitted to great pressure, however, they have not proved effective, and the method, consequently, is only suitable for pipes in which there is no pressure, or only a very trifling one. * * * * * the sellers standard system of screw threads, nuts, and bolt heads. _____________________________________________________ | | | screw threads. | |_____________________________________________________| | | | | | | | diam. |threads | diameter | area of | width | | of | per | at root of | bolt at | of | | screw. | inch. | thread. | root of | flat. | | | | | thread. | | |________|________|_________________|_________|_______| | | | | | | | | / | | . | / | . | . | | / | | . | / | . | . | | / | | . | / | . | . | | / | | . | / | . | . | | / | | . | / | . | . | | / | | . | / | . | . | | / | | . | / | . | . | | / | | . | / | . | . | | / | | . | / | . | . | | | | | | | | | | | . | / | . | . | | - 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/ | / | / | | / | / | | - / | / | / | | / | / | - / | - / | / | / | | - / | | - / | - / | / | / | | - / | - / | - / | - / | / | / | | - / | - / | - / | - / | / | / | | | | | | | | | - / | - / | - / | - / | | / | | - / | - / | - / | - / | - / | - / | | | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | | | | | | | | - / | - / | - / | - / | | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | | - / | - / | | | | | | | | | - / | - / | - / | - / | | - / | | | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | | | | | | | | - / | - / | - / | - / | | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | | | | | | | | - / | - / | - / | - / | | - / | | | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | | - / | |_________|__________|__________|__________|_________|_________| _____________________________________________________________ | | | bolt heads. | |_____________________________________________________________| | | | | | | | | short | short | long | long | thick- | thick- | | diam. | diam. | diam. | diam. | ness | ness | | rough. | finish. | rough. | rough. | rough. | finish. | | | | | | | | | (hex.) | (hex.) | (hex.) | (square) | | | |_________|_________|__________|__________|_________|_________| | | | | | | | | / | / | / | / | / | / | | / | / | / | / | / | / | | / | / | / | / | / | / | | / | / | / | - / | / | / | | / | / | | - / | / | / | | / | / | - / | - / | / | / | | - / | | - / | - / | / | / | | - / | - / | - / | - / | / | / | | - / | - / | - / | - / | / | / | | | | | | | | | - / | - / | - / | - / | / | / | | - / | - / | - / | - / | / | - / | | | - / | - / | - / | | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | | | | | | | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | | - / | - / | | | | | | | | | - / | - / | - / | - / | - / | - / | | | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | | | | | | | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | | | | | | | | - / | - / | - / | - / | - / | - / | | | - / | - / | - / | | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / | - / | - / | | - / | - / | - / | - / - / | - / | |_________|_________|__________|__________|_________|_________| the dimensions given for diameter at root of threads are also those for diameter of hole in nuts and diameter of lap drills. all bolts and studs / in. diameter and above, screwed into boilers, have threads per inch, sharp thread, a taper of / in. per inch; tap drill should be / in. less than normal diameter of bolts. the table is based upon the following general formulæ for certain dimensions: short diam. rough nut or head = / diam. of bolt + / . " finished nut or head = / diam. of bolt + / . thickness rough nut = diameter of bolt. thickness finished nut = diameter of bolt - / . thickness rough head = / short diameter. thickness finished head = diameter of bolt - / . * * * * * an english railway ferry boat. [illustration: an english railway ferry boat.] the illustrations above represent a double screw steam ferry boat for transporting railway carriages, vehicles, and passengers, etc., designed and constructed by messrs. edwards and symes, of cubitt town, london. the hull is constructed of iron, and is of the following dimensions: length ft.; beam ft.; over sponsons ft. the vessel was fitted with a propeller, rudder, and steering gear at each end, to enable it to run in either direction without having to turn around. the boat was designed for the purpose of working the train service across the bay of san juan, in the island of puerto rico, and for this purpose a single line of steel rails, of meter gauge, is laid along the center of the deck, and also along the hinged platforms at each end. in the engraving these platforms are shown, one hoisted up, and the other lowered to the level of the deck. when the boat is at one of the landing stages, the platform is lowered to the level of the rails on the pier, and the carriages and trucks are run on to the deck by means of the small hauling engine, which works an endless chain running the whole length of the deck. the trucks, etc., being on board, the platform is raised by means of two compact hand winches worked by worm and worm-wheels in the positions shown; thus these two platforms form the end bulwarks to the boat when crossing the bay. on arriving at the opposite shore the operation is repeated, the other platform is lowered, and the hauling engine runs the trucks, etc., on to the shore. with a load of tons the draught is ft. the seats shown on the deck are for the convenience of foot passengers, and the whole of the deck is protected from the sun of that tropical climate by a canvas awning. the steering of the vessel is effected from the bridge at the center, which extends from side to side of the vessel, and there are two steering wheels with independent steering gear for each end, with locking gear for the forward rudder when in motion. the man at the wheel communicates with the engineer by means of a speaking tube at the wheel. there is a small deck house for the use of deck stores, on one side of which is the entrance to the engine room. the cross battens, shown between the rails, are for the purpose of horse traffic, when horses are used for hauling the trucks, or for ordinary carts or wagons. the plan below deck shows the arrangement of the bulkheads, with a small windlass at each end for lifting the anchors, and a small hatch at each side for entrance to these compartments. the central compartment contains the machinery, which consists of a pair of compound surface condensing engines, with cylinders in. and in. in diameter; the shafting running the whole length of the vessel, with a propeller at each end. steam is generated in a steel boiler of locomotive form, so arranged that the funnel passes through the deck at the side of the vessel; and it is designed for a working pressure of lb. per square inch. this boiler also supplies steam for the small hauling engine fixed on the bulkhead. light to this compartment is obtained by means of large side scuttles along each side of the boat and glass deck lights, and the iron grating at the entrance near the deck house. this boat was constructed in six pieces for shipment, and the whole put together in the builders' yard. the machinery was fixed, and the engine driven by steam from its own boiler, then the whole was marked and taken asunder, and shipped to the west indies, where it was put together and found to answer the purpose intended.--_engineering._ * * * * * [for the scientific american.] the problem of flight, and the flying machine. as a result of reading the various communications to the scientific american and supplement, and _van nostrand's engineering magazine_, including descriptions of proposed and tested machines, and the reports of the british aeronautical society, the writer of the following concludes: that, as precedents for the construction of a successful flying machine, the investigation of some species of birds as a base of the principles of all is correct only in connection with the species and habits of the bird; that the _general mechanical principles_ of flight applicable to the _operation_ of the _same unit_ of wing in _all_ species are alone applicable to the flying machine. that these principles of _operation_ do not demand the principles of _construction_ of the bird. that as the wing is in its stroke an arc of a screw propeller's operation, and in its angle a screw propeller blade, its animal operation compels its reciprocation instead of rotation. that the swifter the wing beat, the more efficient its effect per unit of surface, the greater the load carried, and the swifter the flight. that the screw action being, in full flight, that of a screw propeller whose axis of rotation forms a slight angle with the vertical, the distance of flight per virtual "revolution" of "screw" wing far exceeds the pitch distance of said "screw." that consequently a bird's flight answers to an iceboat close hauled; the wing _force_ answering to the _wind_, the wing _angle_ to the _sail_, the bird's _weight_ to the leeway fulcrum of the _ice_, and the passage across direction of the _wing_ flop to the fresh _moving_ "inertia" of the wind, both yielding a maximum of force to bird or iceboat. that the speed of _reciprocation_ of a fly's _wing_ being equivalent to a _screw rotation_ of , per minute, proves that a _screw_ may be run at this speed without losing efficiency by centrifugal vacuum. that as the _object_ of wing or screw is to mount upon the inertia of the particles of a mobile fluid, and as the rotation of steamship propellers in water--a fluid of many times the inertia of air--is _already_ in _excess_ of the highest speed heretofore tried in the propellers of moderately successful flying machines, it is plain that the speed employed in _water_ must be many times exceeded in _air_. that with a _sufficient_ speed of rotation, the supporting power of the inertia of air must _equal_ that of _water_. that as mere speed of rotation of propeller _shaft_, minus blades, must absorb but a small proportion of power of engine, the addition of blades will not cause more resistance than that actually encountered from inertia of air. that this must be the measure of load lifted. that without _slip_ of screw, the actual _power_ expended, will be little in _excess_ of that required to support the machine in _water_, with a slower rotation of screw. that in case the same _power_ is expended in water or air, the only difference will lie in the sizes and speed of engines or screws. that the _greater_ the speed, the _less_ weight of engine, boiler, and screw must be, and the stronger their construction. that, in consequence, solid metal worked down, instead of bolts and truss work, must be used. that as the bird wing is a screw in action, and acts _directly_ between the inertias of the load and the air, the position and operation of the screw, to the load, must imitate it. that, in consequence, machines having wing planes, driven _against_ one inertia of air by screws acting in the line, of flight against another inertia of air, lose fifty per cent. of useful effect, besides exposing to a head wind the cross section of the stationary screw wing planes and the rotating screw discs; and supporting the dead weight of the wing planes, and having all the screw slip in the line of flight, and carrying slow and heavy engines. that as a result of these conclusions, the supporting and propelling power should be expressed in the rotation of screws combining both functions, the position of whose planes of rotation to a fixed horizontal line of direction determines the progress and speed of machine upon other lines. that the whole weight carried by the screws should be at all times exactly below the center of gravity of the plane of support, whether it be horizontal or inclined. that while the _permanently_ positioned weight, such as the engines, frame, holding screws, etc., may be rigidly connected to or around the screw plane of support, the variable positioned weight, such as the passenger and the car, should be connected by a _flexible joint_ to the said plane of support. consequently, the car may oscillate without altering its weight position under center of supporting plane, thus avoiding an involuntary alteration of speed or direction of flight. that to steer a machine so constructed, it is merely necessary to move the point of attachment of car to _machine_ proper, out of the center of plane of support in the desired direction, and thus cause the plane of support or rotation of propellers to incline in that direction. that the reservoir of power, the boiler, etc., should be placed in the _car_, and steam carried to engines through joint connecting car with machine. that at present material exists, and power also, of sufficient lightness and strength to admit of a machine construction capable of a limited successful flight in any fair wind and direction. that such _machine_ once built, the finding of a _power_ for long flights will be easy, if not already close at hand in _electricity_. that the _easiest_ design for such _actual machine_ should be adopted, leaving the adaptation of the principles involved to the making of more perfect machines, to a time after the success of the _first_. that such design may be a propeller, and its engine at each end of a steel frame tube, supporting tube horizontally, a car to be supported by a universal joint from center of said tube, and the joint apparatus movable along the tube or a short distance transverse to it, to alter position of center of gravity. that the machine so built might traverse the water as well as air. * * * * * the longhaired pointer mylord. pointers are trained to search for game, and to indicate that they have found the same by standing motionless in front of it, and, when it has been shot, to carry the game to the huntsman. several kinds of pointers are known, such as smooth, longhaired, and bushyhaired pointers. the smoothhaired pointers are better for hunting on high land, whereas the longhaired or bushyhaired dogs are better for low, marshy countries, crossed by numerous streams, etc. mylord, the dog represented in the annexed cut taken from the _illustrirte zeitung_, is an excellent specimen of the longhaired pointer, and is owned by mr. g. borcher, of braunschweig, germany. [illustration: the longhaired pointer, "mylord."] the longhaired pointer is generally above the medium size, powerful, somewhat longer than the normal dog, the body is narrower and not quite as round as that of the smoothhaired dog, and the muscles of the shoulders and hind legs are not as well developed and not as prominent. the head and neck are erect, the head being specially long, and the tail is almost horizontal to the middle, and then curves upward slightly. the long hair hangs in wavy lines on both sides of his body. the expression of his face is intelligent, bright, and good-natured, and his step is light and almost noiseless. the pointer is specially valuable, as it can be employed for many different purposes; he is an excellent dog for the woods, for the woodsman and hunter who uses only one dog for different kinds of game. the intelligence of the german pointer is very great, but he does not develop as rapidly as the english dog, which has been raised for generations for one purpose only. the german pointer hunts very slowly, but surely. it is not difficult to train this dog, but he cannot be trained until he has reached a certain age. * * * * * lunar heat. by professor c.a. young. one of the most interesting inquiries relating to the moon is that which deals with the heat she sends us, and the probable temperature of her surface. the problem seems to have been first attacked by tschirnhausen and la hire, about ; and they both found, that even when the moon's rays were concentrated by the most powerful burning-lenses and mirrors they could obtain, its heat was too small to produce the slightest perceptible effect on the most delicate thermometers then known. for more than a hundred years, this was all that could be made out, though the experiment was often repeated. it was not until that melloni, with his newly-invented "thermopile," [ ] succeeded in making the lunar heat sensible; and in , taking his apparatus to the top of vesuvius, he obtained not only perceptible, but measurable, results, getting a deviation of four or five divisions of his galvanometer. [footnote : probably most of our readers know that the thermopile consists of a number of little bars of two different metals, connected in pairs, and having the ends joined in a conducting circuit with a galvanometer. if, now, one set of the junctures is heated more than the other set, a current of electricity will be generated, which will affect the galvanometer. the bars are usually made of bismuth and antimony though iron and german silver answer pretty well. they are commonly about half or three-quarters of an inch long, and about half as large as an ordinary match. the "pile" is made of from fifty to a hundred such bars packed closely, but insulated by thin strips of mica, except just at the soldered junctions. with an instrument of this kind and a very delicate galvanometer, professor henry found that the heat from a person's face could be perceived at a distance of several hundred feet. there is however, some doubt whether he was not mistaken in respect to this extreme sensitiveness.] others repeated the experiment several times between this time and , with more or less success; but, so far as i know, the first quantitative result was that obtained in by piazzi smyth during his teneriffe expedition. on the top of the mountain, at an elevation of ten thousand feet, he found that the moon's rays affected his thermopile to the same extent as a standard candle ten feet away. marie davy has since shown that this corresponds to a heating effect of about / of a centigrade degree. the subject was resumed in by lord rosse in ireland; and a long series of observations, running through several years, was made by the aid of his three-foot reflector (not the great _six_-foot instrument, which is too unwieldy for such work). the results of his work have, until very recently, been accepted as authoritative. it should be mentioned that, at about the same time, observations were also made at paris by marie davy and martin; but they are generally looked upon merely as corroborative of rosse's work, which was more elaborate and extensive. rosse considered that his results show that the heat from the moon is mainly _obscure, radiated_ heat; the _reflected_ heat, according to him, being much less in amount. a moment's thought will show that the moon's heat must consist of two portions. first, there will be _reflected solar heat_. the amount and character of this will depend in no way upon the temperature of the moon's surface, but solely upon its reflecting power. and it is to be noted that moon-_light_ is only a part of this reflected radiant energy, differing from the invisible portion of the same merely in having such a wave-length and vibration period as to bring it within the range of perception of the human eye. the second portion of the heat sent us by the moon is that which she emits on her own account as a warm body--warmed, of course, mainly, if not entirely, by the action of the sun. the amount of _this_ heat will depend upon the temperature of the moon's surface and its radiating power; and the temperature will depend upon a number of things (chiefly heat-absorbing power of the surface, and the nature and density of the lunar atmosphere, as well as the supply of heat received from the sun), being determined by a balance between give and take. so long as more heat is received in a second than is thrown off in the same time, the temperature will rise, and _vice versa_. it is to be noted, further, that this second component of the moon's thermal radiance must be mainly what is called "obscure" or dark heat, like that from a stove or teakettle, and characterized by the same want of penetrative power. no one knows why at present; but it is a fact that the heat-radiations from bodies at a low temperature--radiations of which the vibrations are relatively slow, and the wave-length great--have no such power of penetrating transparent media as the higher-pitched vibrations which come from incandescent bodies. a great part, therefore, of this contingent of the lunar heat is probably stopped in the upper air, and never reaches the surface of the earth at all. now, the thermopile cannot, of course, discriminate directly between the two portions of the lunar heat; but to some extent it does enable us to do so indirectly, since they vary in quite a different way with the moon's age. the simple _reflected_ heat must follow the same law as moonlight, and come to its maximum at full moon. the _radiated_ heat, on the other hand, will reach its maximum when the average temperature of that part of the moon's surface turned toward the earth is highest; and this must be some time after full moon, for the same sort of reasons that make the hottest part of a summer's day come two or three hours after noon. the conclusion early reached by lord rosse was that nearly all the lunar heat belonged to the second category--dark heat _radiated_ from the moon's warmed surface, the _reflected_ portion being comparatively small--and he estimated that the temperature of the hottest parts of the moon's surface must run as high as ° f.; well up toward the boiling-point of mercury. since the lunar day is a whole month long, and there are never any clouds in the lunar sky, it is easy to imagine that along toward two or three o'clock in the lunar afternoon (if i may use the expression), the weather gets pretty hot; for when the sun stands in the lunar sky as it does at boston at two p.m., it has been shining continuously for more than two hundred hours. on the other hand, the coldest parts of the moon's surface, when the sun has only just risen after a night of three hundred and forty hours, must have a temperature more than a hundred degrees below zero. lord rosse's later observations modified his conclusions, to some extent, showing that he had at first underestimated the percentage of simple reflected heat, but without causing him to make any radical change in his ideas as to the maximum heat of the moon's surface. for some time, however, there has been a growing skepticism among astronomers, relating not so much to the correctness of his measures as to the computations by which he inferred the high percentage of obscure radiated beat compared with the reflected heat, and so deduced the high temperature of lunar noon. professor langley, who is now engaged in investigating the subject, finds himself compelled to believe that the lunar surface never gets even comfortably warm--because it has no blanket. it receives heat, it is true, from the sun, and probably some twenty-five or thirty per cent. more than the earth, since there are no clouds and no air to absorb a large proportion of the incident rays; but, at the same time, there is nothing to retain the heat, and prevent the radiation into space as soon as the surface begins to warm. we have not yet the data to determine exactly how much the temperature of the lunar rocks would have to be raised above the absolute zero (- ° c. or - ° f.) in order that they might throw off into space as much heat in a second as they would get from the sun in a second. but professor langley's observations, made on mount whitney at an elevation of fifteen thousand feet, when the barometer stood at seventeen inches (indicating that about fifty-seven per cent. of the air was still above him), showed that rocks exposed to the perpendicular rays of the sun were not heated to any such extent as those at the base of the mountain similarly exposed; and the difference was so great as to make it almost certain that a mass of rock not covered by a reasonably dense atmosphere could never attain a temperature of even ° or ° f. under solar radiation, however long continued. it must, in fact, be considered at present extremely doubtful whether any portion of the moon's surface ever reaches a temperature as high as - °. the subject, undoubtedly, needs further investigation, and it is now receiving it. professor langley is at work upon it with new and specially constructed apparatus, including a "bolometer" so sensitive that, whereas previous experimenters have thought themselves fortunate if they could get deflections of ten or twelve galvanometric divisions to work with, he easily obtains three or four hundred. we have no time or space here to describe professor langley's "bolometer;" it must suffice to say that it seems to stand to the thermopile much as that does to the thermometer. there is good reason to believe that its inventor will be able to advance our knowledge of the subject by a long and important step; and it is no breach of confidence to add that so far, although the research is not near completion yet, everything seems to confirm the belief that the radiated heat of the moon, instead of forming the principal part of the heat we get from her, is relatively almost insignificant, and that the lunar surface now never experiences a _thaw_ under any circumstances. since the superstition as to the moon's influence upon the wind and weather is so widespread and deep seated, a word on that subject may be in order. in the first place, since the total heat received from the moon, even according to the highest determination (that of smyth), is not so much as . of that received from the sun, and since the only hold the moon has on the earth's weather is through the heat she sends us (i ignore here the utterly insignificant atmospheric _tide_), it follows necessarily that her influence _must_ be very trifling. in the next place, all carefully collated observations show that it _is_ so, and not only trifling, but generally absolutely insensible. for example, different investigators have examined the question of nocturnal cloudiness at the time of full moon, there being a prevalent belief that the full moon "eats up" light clouds. on comparing thirty or forty years' observations at each of several stations (greenwich. paris, etc.), it is found that there is no ground for the belief. and so in almost every case of imagined lunar meteorological influence. as to the coincidence of weather changes with changes of the moon, it is enough to say that the idea is absolutely inconsistent with that progressive movement of the "weather" across the country from west to east, with which the signal service has now made us all so familiar. princeton, april , . * * * * * apple tree borers. the apple tree borers have destroyed thousands of trees in new england, and are likely to destroy thousands more. there are three kinds of borers which assail the apple tree. the round headed or two striped apple tree borer, _saperda candida_, is a native of this country, infesting the native crabs, thorn bushes, and june berry. it was first described by thomas say, in , but was probably widely distributed before that. in his "insects injurious to fruit," prof. saunders thus describes the borer: "in its perfect state it is a very handsome beetle, about three-quarters of an inch long, cylindrical in form, of a pale brown color, with two broad, creamy white stripes running the whole length of its body; the face and under surface are hoary white, the antennæ and legs gray. the females are larger than the males, and have shorter antennæ. the beetle makes its appearance during the months of june and july, usually remaining in concealment during the day, and becoming active at dusk. the eggs are deposited late in june and during july, one in a place, on the bark of the tree, near its base. within two weeks the young worms are hatched, and at once commence with their sharp mandibles to gnaw their way through the outer bark to the interior. it is generally conceded that the larvæ are three years in reaching maturity. the young ones lie for the first year in the sapwood and the inner bark, excavating flat, shallow cavities, about the size of a silver dollar, which are filled with their sawdust-like castings. the holes by which they enter being small are soon filled up, though not until a few grains of castings have fallen from them. their presence may, however, often be detected in young trees from the bark becoming dark colored, and sometimes dry and dead enough to crack." on the approach of winter, it descends to the lower part of its burrow, where it remains inactive until spring. the second season it continues its work in the sapwood, and in case two or three are at work in the same tree may completely girdle it, thus destroying it. the third year it penetrates to the heart of the tree, makes an excavation, and awaits its transformation. the fourth spring it comes forth a perfect beetle, and lays its eggs for another generation. the flat-headed borer. the flat-headed apple tree borer, _chrysobothris femorata_, is also a native of this country. it is a very active insect, delights to bask in the hot sunshine; runs up and down the tree with great rapidity, but flies away when molested. it is about half an inch in length. "it is of a flattish, oblong form, and of a shining, greenish black color, each of its wing cases having three raised lines, the outer two interrupted by two impressed transverse spots of brassy color dividing each wing cover into three nearly equal portions. the under side of the body and legs shine like burnished copper; the feet are shining green." this beetle appears in june and july, and does not confine its work to the base of the tree, but attacks the trunk in any part, and sometimes the larger branches. the eggs are deposited in cracks or crevices of the bark, and soon hatch. the young larva eats its way through the bark and sapwood, where it bores broad and flat channels, sometimes girdling and killing the tree. as it approaches maturity, it bores deeper into the tree, working upward, then eats out to the bark, but not quite through the bark, where it changes into a beetle, and then cuts through the bark and emerges to propagate its kind. this insect is sought out when just beneath the bark, and devoured by woodpeckers and insect enemies. another borer, the long-horned borer, _leptostylus aculifer_, is widely distributed, but is not a common insect, and does not cause much annoyance to the fruit grower. it appears in august, and deposits its eggs upon the trunks of apple trees. the larvæ soon hatch, eat through the bark, and burrow in the outer surface of the wood just under the bark. protection against borers. the practical point is, what remedies can be used to prevent the ravages of the borers? the usual means of fighting the borers is, to seek after them in the burrows, and try to kill them by digging them out, or by reaching them with a wire. this seems to be the most effectual method of dealing with them after they have once entered the tree, but the orchardist should endeavor to prevent the insects from entering the tree. for this purpose, various washes have been recommended for applying to the tree, either for destroying the young larvæ before they enter the bark, or for preventing the beetles depositing their eggs. it has been found that trees which have been coated with alkaline washes are avoided by beetles when laying their eggs. prof. saunders recommends that soft soap be reduced to the consistency of a thick paint, by the addition of a strong solution of washing soda in water, and be applied to the bark of the tree, especially about the base or collar, and also extended upward to the crotches where the main branches have their origin. it should be applied in the evening of a warm day, so that it may dry and form a coating not easily dissolved by the rain. this affords a protection against all three kinds of borers. it should be applied early in june, before the beetles begin to lay their eggs, and again in july, so as to keep the tree well protected. hon. t.s. gold, of connecticut, at a meeting of the massachusetts state board of agriculture, in regard to preventing the ravages of the borer, said: "a wash made of soap, tobacco water, and fresh cow manure mingled to the consistency of cream, and put on early with an old broom, and allowed to trickle down about the roots of the tree, has proved with me a very excellent preventive of the ravages of the borer, and a healthful wash for the trunk of the tree, much to be preferred to the application of lime or whitewash, which i have often seen applied, but which i am inclined to think is not as desirable an application as the potash, or the soda, as this mixture of soft soap and manure." j.b. moore, of concord, mass., at the same meeting said, in regard to the destruction of the borer: "i have found, i think, that whale oil soap can be used successfully for the destruction of that insect. it is a very simple thing; it will not hurt the tree if you put it on its full strength. you can take whale oil soap and dilute until it is about as thick as paint, and put a coating of it on the tree where the holes are, and i will bet you will never see a borer on that tree until the new crop comes. i feel certain of it, because i have done it." for borers, tarred paper or feet wide has been recommended to be wrapped about the base of the trunk of the tree, the lower edge being or inches below the surface of the soil. this prevents the two-striped borer from laying its eggs in the tree, but would not be entirely effectual against the flat-headed borer, which attacks any part of the trunk and the branches. by the general use of these means for the prevention of the ravages of the borers, the damages done by these insects could be brought within very narrow limits, and hundreds of valuable apple trees saved. h. reynolds, m.d. livermore falls, me. * * * * * keffel's germinating apparatus. the apparatus represented in the annexed cut is designed to show the quality of various commercial seeds, and make known any fraudulent adulterations that they may have undergone. it is based upon a direct observation, of the germination of the seeds to be studied. [illustration: keffel's germinating apparatus.] the apparatus consists of a cylindrical vessel containing water to the height of . m. above the water is a germinating disk containing apertures for the insertion of the seeds to be studied, the germinating end of the latter being directed toward the water. after the seeds are in place the disk is filled with damp sand up to the top of its rim, and the apparatus is closed with a cover which carries in its center a thermometer whose bulb nearly reaches the surface of the water. the apparatus is then set in a place where the temperature is about °, and where there are no currents of air. an accurate result is reached at the end of about twenty or twenty-four hours. as the germinating disk contains apertures for as many seeds, it is only necessary to count the number of seeds that have germinated in order to get the percentage of fresh and stale ones. the aqueous vapor that continuously moistens all the seeds, under absolutely identical conditions for each, brings about their germination under good conditions for accuracy and comparison. if it be desired to observe the starting of the leaves, it is only necessary to remove the cover after the seeds have germinated. this ingenious device is certainly capable of rendering services to brewers, distillers, seedsmen, millers, farmers, and gardeners, and it may prove useful to those who have horses to feed, and to amateur gardeners, since it permits of ascertaining the value and quality of seeds of every nature.--_la nature._ * * * * * millet. the season is now at hand when farmers who have light lands, and who may possibly find themselves short of fodder for next winter feeding, should prepare for a crop of millet. this is a plant that rivals corn for enduring a drought, and for rapid growth. there are three popular varieties now before the public, besides others not yet sufficiently tested for full indorsement--the coarse, light colored millet, with a rough head, hungarian millet, with a smooth, dark brown head, yielding seeds nearly black, and a newer, light colored, round seeded, and later variety, known as the golden millet. hungarian millet has been the popular variety with us for many years, although the light seeded, common millet is but slightly different in appearance or value for cultivation. they grow in a short time, eight weeks being amply sufficient for producing a forage crop, though a couple of weeks more would be required for maturing the seed. millet should not be sown in early spring, when the weather and ground are both cold. it requires the hot weather of june and july to do well; then it will keep ahead of most weeds, while if sown in april the weeds on foul land would smother it. millet needs about two months to grow in, but if sowed late in july it will seem to "hurry up," and make a very respectable showing in less time. we have sown it in august, and obtained a paying crop, but do not recommend it for such late seeding, as there are other plants that will give better satisfaction. golden millet has been cultivated but a few years in this country, and as yet is but little known, but from a few trials we have been quite favorably impressed with it. it is coarser than the other varieties, but cattle appear to be very fond of it nevertheless. it resembles corn in its growth nearly as much as grass, and, compared with the former, it is fine and soft, and it cures readily, like grass, and may be packed away in hay mows with perfect safety. it is about two weeks later than the other millets, and consequently cannot be grown in quite so short a time, although it may produce as much weight to the acre, in a given period, as either of the other more common varieties. a bushel of seed per acre is not too much for either variety of millet.--_n.e. farmer._ * * * * * a catalogue containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. * * * * * all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. * * * * * all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . , stitched in paper, or $ . bound in stiff covers. * * * * * combined rates--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway, new york, n.y. * * * * * patents. in connection with the scientific american, messrs munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats, trade marks, their costs, and how procured. address munn & co., broadway, new york. branch office, cor. f and th sts., washington, d.c. [illustration] scientific american supplement no. new york, march , . scientific american supplement. vol. xlv., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. page i. archÆology.--requirements of palestine explorer ii. biography.--emperor william ii. of germany.--an interesting biographical account of the german emperor, with his latest portrait.-- illustration iii. civil engineering.--heat in great tunnels iv. economics.--causes of poverty v. electricity.--liquid rheostats.--by h. s. webb the neutral use of cables vi. ethnology.--the influence of scenery upon the character of man vii. forestry.--apparatus for obtaining the cubature of trees.-- illustrations viii. gymnastics.--a novel way of riding a bicycle. -- illustration ix. hydrography.--influence of ocean currents on climate x. landscape gardening.--park making xi. marine engineering.--the newfoundland and nova scotia passenger steamer "bruce."-- illustration xii. mechanical engineering.--machine moulding without stripping plates.--by e. h. mumford.--a full description of an ingenious moulding machine.-- illustrations xiii. medicine.--the progress of medical education in the united states deaths under anæsthetics xiv. miscellaneous: engineering notes miscellaneous notes selected formulæ xv. natural history.--tapirs in the zoological garden at breslau.-- illustration xvi. steam engineering.--an english steam fire engine. -- illustration xvii. travel and exploration.--my recent journey from the nile to suakim.--by frederic villiers.--the advance to khartoum.--an important account of the recent travels of the celebrated war correspondent. xviii. technology.--artificial india rubber.--this article describes some important experiments which have been made in which india rubber substitutes have been produced from oil of turpentine deep and frosted etching on glass the koppel electric locomotives.--this article describes a system of electric trolley traction for narrow gage railroads.-- illustrations slate and its applications.--this article details some of the various uses to which slate is put in the arts, with a view of slate store vats for breweries. birthplace of the oilcloth industry. * * * * * [illustration: latest portrait of william ii. of germany] emperor william ii. of germany. since william ii. of germany ascended the throne as german emperor and king of prussia, on june , , the eyes of europe have been fixed on him. he has always been rather an unknown quantity, and he is regarded by the powers as an _enfant terrible_. the press of the world delights in showing up his weak points, and the "war lord" undoubtedly has them, but, at the same time, he has qualities which are to be admired and which make him conspicuous among the rulers of europe. he is popular in germany, and it is not surprising, for, in spite of being autocratic to the last degree, he is honest, courageous, ambitious, hard working, and, withal, a thorough german, being intensely patriotic. indeed, if the people of the fatherland had the right to vote for a sovereign, they would undoubtedly choose the present constitutional ruler, for, while the virtues we have named may seem commonplace, they are not so when embodied in an emperor. one thing which places william at a disadvantage is his excessive frankness, which is, in him, almost a fault, for if he couched his utterances in courtly or diplomatic phrases, they would pass unchallenged, instead of being cited to ridicule him. his mistakes have largely resulted from his impulsive nature coupled with chauvinism, which is, perhaps, justifiable, or, at least, excusable, in a ruler. since the time when william was a child he evidenced a strong desire to become acquainted with the details of the office to which his lofty birth entitled him. it is doubtful if any king since the time of frederick the great has studied the routine of the public offices and has made such practical inspections of industries of all kinds; indeed, there is hardly a man in germany who has more general knowledge of the material development of the country. in the army he has worked his way up like any other officer and has a firm grasp on all the multifarious details of the military establishment of the great country. he believes in militarism, or in force to use a more common expression, but in this he is right, for it has taken two hundred and fifty years to bring prussia to the position she now holds, and what she has gained at the point of the sword must be retained in the same way. the immense sacrifices which the people make to support the army and navy are deemed necessary for self-preservation, and with france on one side and russia on the other, there really seems to be ample excuse for it. to-day the german army is as ready as in , when von moltke walked down the unter den linden, the day after hostilities were declared, looking in the shop windows. no ruler, except possibly peter the great, ever gave so many _ex cathedra_ opinions on so many different subjects in the same length of time, and of course it cannot be supposed that he has not made mistakes, but it shows that it is only by prodigious industry that he has been able to gather the materials on which these utterances are based. he is indeed the "first servant of the state," and long before his court or indeed many of the housemaids of berlin are awake, he is up and attending to affairs of all kinds. he is a great traveler, and knows europe from the north cape to the golden horn; and while flying across country in his comfortable vestibuled train, he dispatches business and acquires an excellent idea of the country, and no traveler can speak more intelligently of the countries through which he has traveled, and this information is brought out with good effect in his excellent after-dinner speeches. in speaking of the versatility of the emperor, something should be said of him as a sportsman. he has given a splendid example to the germans. he has tried to introduce baseball, football and polo, three american games. this may be traced to the time when poultney bigelow and j. a. berrian were the emperor's playmates. fenimore cooper was one of the favorite authors with the young scion of royalty. the emperor is fond of hunting, yachting, tennis and other sports and is never so happy as when he stands on the bridge of the royal yacht hohenzollern. he is a well known figure at cowes and won the queen's cup in . william ii. was born january , , in berlin, and until he was fourteen years old his education was intrusted to dr. hintzpeter, assisted by major von gottberg, who was military instructor. at this time his corps of teachers was increased by the addition of prediger persius, who prepared him for his confirmation, which took place september , , at potsdam. as william was to lead an active life, it was thought best to send him to the gymnasium at cassel. orders were given that he and his younger brother henry, who accompanied him, should receive the same treatment as the other pupils, and this order was strictly obeyed. he graduated from this school january , , just before his eighteenth birthday. after this his military career began with his entrance as an officer into the first garde-regiment at potsdam, that he might become thoroughly acquainted with practical service. the young prince was assigned to the company which his father had once commanded. after serving here for a short time he went to the university at bonn, and from there he went back to the army again. emperor william ascended the throne in june, , upon the death of his father frederick iii. in he was betrothed to augusta victoria, princess of schleswig-holstein, and on february , , they were married. the empress is about a year younger than the emperor, and makes an excellent mother to her four little sons, to whom she is devoted. their oldest child, little prince william, the present crown prince, was born at potsdam, may , . his father's devotion to the army will doubtless prompt him to make a soldier of his son at an early age; in fact, he wore the uniform of a fusilier of the guard before he was six years old. the imperial family consists of seven children. the eldest, the crown prince of germany and prussia, is prince friedrich-wilhelm-victor-august-ernst, born may , . the second child is prince wilhelm-eitel-friedrich-christian-karl, born july , . the third is prince adalbert-ferdinand-berenger-victor, born july , . prince august-wilhelm-heinrich-victor was born january . . the fifth child, prince oscar-karl-gustav-adolf, was born july , . the sixth child is prince joachim-francois-humbert. he was born december , . the youngest is a girl, princess victoria-louise-adelaide-mathilde-charlotte. she was born september , . our engraving is from the last portrait of the emperor william, and we are indebted for it to the illustrirte zeitung. * * * * * my recent journey from the nile to suakim. by frederic villiers, in the journal of the society of arts. the advance to khartoum. the recent campaign in the soudan was a bloodless one to the correspondent with the expedition, or, rather, on the tail of the advance. yet i think, in spite of this little drawback, there is enough in the vicissitudes of my colleagues and myself during the recent advance of the egyptian troops up the nile to warrant me addressing you this afternoon. especially as toward the end of the campaign the sirdar, or commander-in-chief of the egyptian army, sir herbert kitchener, became more sympathetic with our endeavors to get good copy for our journals, and allowed us to return home by the old trade route of the eastern soudan, over which no european had passed since the revolt of the eastern tribes in . unfortunately, the period for campaigning in the soudan is in the hottest months in the year, on the rising of the nile at the end of july, when the cataracts begin to be practicable for navigation. at the same time, in spite of the heat, it is the healthiest period, for the water, in its brown, muddy, pea soup state, is wholesomer to drink, and the banks of the river, which, when exposed at low nile, give off unhealthy exhalations, are protected from spreading fever germs by the flood. to show you how much the people of egypt depend for their very existence on this extraordinary river, the average difference between high and low nile, giving favorable results, is feet. twenty-eight feet would cause serious damage by inundation, and the nile as low as feet would create a famine. the flood of the river depends entirely on the equatorial rains which cause the upper white nile to rise in april and the blue nile early in june. the muddy atbara, joining her two sisters about the same time, sends the flood down to lower egypt toward the end of august at the rate of miles a day. the blue nile in the middle of september falls rapidly away, while the atbara leaves the trio in october. the white nile is then left by herself to recede slowly and steadily from a current of four knots an hour to a sluggish and, in many parts, an unwholesome stream. flies and mosquitoes increase, and fever is rife. i arrived in cairo on a sweltering day in july, and found four colleagues, who had been waiting for a week the sirdar's permission to proceed to the front, still waiting. luckily, the day after my arrival a telegram came from headquarters, saying that "we might proceed as far as assouan and their await further orders." this, anyhow, was a move in the right direction; so we at once started. it was rather a bustle for me to get things ready, for sunday blocked the way and little could be done, even on that day, in cairo. i procured a servant, a horse and two cases of stores, for the cry was "nothing to be had up country in the shape of food; hardly sufficient sustenance to keep the flies alive." my colleagues, who had the start of me, were able to procure many luxuries--a case of cloudy ammonia for their toilet, and one of chartreuse, komel and benedictine to make their after dinner coffee palatable, and some plum pudding, if christmas should still find them on the warpath, were a few of the many items that made up the trousseau of these up-to-date war correspondents, though at least one of them had been wedded to the life for many years. unfortunately i had no time to procure these luxuries, and i had to proceed ammonialess and puddingless to the seat of war. my comrades were quite right. why not do yourself well if you can? one of them even went in for the luxury of having three shooting irons, two revolvers and a double-barrel slug pistol, so that when either of the weapons got hot while he was holding baggara horsemen at bay, there was always one cooling, ready to hand. he also, which i believe is a phenomenal record with any campaigner, took with him thirteen pairs of riding breeches, a half dozen razors and an ice machine. even our commander-in-chief, when campaigning, denies himself more than two shirts and never travels with ice machines. but the thirteen pairs impressed me considerably. why thirteen, more than fifteen, or any other number? i came to the conclusion that my colleague must certainly be a member of that mystic body the "thirteen club," and as he had to bring in the odd number somewhere to keep the club fresh in his memory, he occasionally sat upon it. i found, after all, there was some wisdom in his eccentricity, for, when riding the camel, mounted on the rough saddle of the country, i often wished that i had my friend's forethought, and i should have been glad to have supplemented mine with his odd number. no doubt my colleague's idea in having such a variety of nether garments was to use them respectively, on a similar principle to the revolvers, when he rode in hot haste with his vivid account of the latest battle to the telegraph office. but, unfortunately, this recent campaign did not, after all, necessitate these elaborate preparations, for there were no dervishes for us to shoot at or descriptions of bloody battles to be telegraphed. at all events, the cloudy ammonia and the thirteen breeches, with the assistance of a silken sash--a different color for each day of the week--made the brightest and smartest looking little man in camp. however, when i reflect on this new style of war correspondent, who, i forgot to mention, also carried with him two tents, a couple of beds, sundry chairs and tables, a silver-mounted dressing case, two baths, and a gross of toothpicks, and i think of the severe simplicity of the old style of campaigning when a famous correspondent who is still on the warpath, and who always sees the fighting if there be any, on one arduous campaign took with him the modest outfit of a tooth brush and a cake of carbolic soap, i joyfully feel that with the younger generation our profession is keeping pace with the luxury of the times. from berber to suakim. toward the end of the campaign four colleagues--messrs. knight, gwynne, scudamore, maud--and myself, took this opportunity of traversing a country very little known to the outside world, and a route which no european had followed for fourteen years, from berber to suakim. moreover, there was a spice of adventure about it; there was an uncertainty regarding an altogether peaceful time on the way--a contingency which always appeals strongly to englishmen of a roving and adventurous disposition. only quite recently raids organized by the apparently irrepressible osman digna had been successfully carried out a few miles north and south of berber. at the moment general hunter, with two battalions of troops, was marching along the banks of the river atbara to hunt for osman and his followers, but there was much speculation as to whether five-and-twenty dervish raiders were still this side of the river, and drawing their water from the wells on the suakim road. i was hardly prepared for this journey--one, probably, of twelve days--for my campaigning outfit, which i was compelled to leave on board my nugger on the nile, had not yet arrived in berber. unfortunately, i could not wait for the gear, as the sirdar insisted on our departure at once, for the road would be certainly insecure directly general hunter returned from covering our right flank on the atbara. i had no clothes but what i stood up in, and i had been more or less standing up in them without change for the last two weeks. our caravan of nineteen camels, with two young ones, quite babies, following their mothers, and a couple of donkeys, about seven in the evening of the th of october quitted the mud-baked town of berber, sleeping in the light of a new moon, and silently moved across the desert toward the eastern star. next morning at the morabeh well, six miles from berber, our camels having filled themselves up with water, and our numerous girbas, or water skins, being charged with the precious liquid--till they looked as if they were about to burst--our loads were packed and we started on a journey of fifty-two miles before the next water could be reached. we made quite a formidable show trailing over the desert. probably it would have been more impressive if our two donkeys had restrained their ambition, and kept in the rear instead of leading the van. but animals mostly have their own way in these parts, and asses are no exception to this rule. the two baby camels commenced "grousing" with their elders directly we halted or made a fresh advance; they probably had an inkling of what was in store for them. after all, the world must seem a hard and unsympathetic place when, having only known it for two or three weeks, you are compelled to make a journey of miles to keep up with your commissariat. one of these babies was only in its eighteenth day. in spite of its tender youth the little beast trotted by the side of its mother, refreshing itself whenever we came to a halt with a pull from her teats, and, to the astonishment of all, arrived in suakim safe and sound after twelve days' marching. to the uninitiated regarding the "grousing" of camels, i should explain that it is a peculiar noise which comes from their long funnel necks early or late, and for what reason it is difficult to tell. sometimes the sound is not unlike the bray of an ass, occasionally it reaches the dignity of the roar of a lion with the bleating of a goat thrown in, then as quickly changes to the solemnity of a church organ. it is altogether so strange a sound that nothing but a phonograph could convey any adequate idea of it. it is a thing to be heard. no pen can properly describe it. after a long march, and when you are preparing to relieve the brute of his load, he begins to grouse. when he is about to start in the morning he grouses. if you hit him, he grouses; if you pat his neck gently, he grouses; if you offer him something to eat, he grouses; and if you twist his tail, he makes the same extraordinary noise. the camel evidently has not a large vocabulary, and he is compelled to express all his various sensations in this simple manner. the first part of our journey was monotonous enough, miles and miles of weary sandy plains, with alternate stretches of agabas or stony deserts, scored with shallow depressions, where torrential rains had recently soaked into the sand, leaving a glassy, clay-like surface, which had flaked or cracked into huge fissures under the heat of the fierce sun. and at every few hundred yards we came to patches of coarse camel grass, which had evidently cropped up on the coming of the rain, and, by its present aspect, seemed to feel very sorry that it had been induced to put in an appearance, for its sustenance was now fast passing into vapor, and its green young life was rapidly dying out as the sun scorched the tender shoots to the roots. but camels thrive on this parched-up grass, and our brutes nibbled at it whenever one slackened the head-rope. we traversed the dreary plain, marked every few yards by the bleached bones of camels fallen by the way; the only living thing met with for two days being a snake of the cobra type trailing across our path. the evening of the second day we camped in a long wadi, or shallow valley, full of mimosa trees, where our camels were hobbled and allowed to graze. they delighted in nibbling the young branches of these prickly acacias, which carry thorns at least an inch in length, that serve excellently well for toothpicks. yet camels seem to rejoice in browsing off these trees, and chew up their thorns without blinking. this i can partly understand, for the camel's usual diet of dry, coarse grass must become rather insipid, and as we sometimes take "sauce piquante" with our cold dishes, so he tickles his palate with one inch thorns. climbing ridge after ridge of the dunes, we at last saw stretching before us in the moonlight the valley of obak, an extensive wadi of mimosa and sunt trees. our guides halted on a smooth stretch of sand, and i wondered why we were not resting by the wells. near were three native women squatting round a dark object that looked to me, in the faint light of the moon, like a tray. i walked up to them, thinking they might have some grain upon it for sale, but found to my surprise that it was a hole in the sand, and i realized at once that this must be a well. one of the women was manipulating a leather bucket at the end of a rope, which after a considerable time she began hauling up to the surface. it was about half full of thick, muddy water. further on along the wadi i now noticed other groups of natives squatting on the sand doing sentinel over the primitive wells. i never came across a more slovenly method of getting water. the mouths of the holes were not banked or protected; a rain storm or sand drift at any moment might have blocked them for a considerable period. not being able to get water for the camels was a serious matter, as our animals were not of the strongest, nor had they been recently trained for a long journey without water. this was the evening of the third day from berber, and many of the poor brutes were showing signs of weakness. we resolved, therefore, to hurry on at once to the next well, that of ariab; so we left the inhospitable wadi, and started at three in the morning on our next stretch of fifty-three miles. these night marches were pleasant enough; it was only the hour or two before dawn when the heaviness of sleep troubled us; but just as we began nodding, and felt in danger of falling off our camels, the keen change in the temperature which freshens the desert in the early morning braced us up, and, fully awake, we watched for the coming of venus. as she sailed across the heavens, she flooded the desert with a warm, soft light, which in its luminosity equaled an english summer moon, and shortly seemingly following her guidance, the great fiery shield of the sun stood up from the horizon, and broad day swept over the plain. toward the evening we found ourselves in a bowlder-strewn basin amid rocky, sterile hills, evidently the offshoots and spurs of the jeb-el-gharr, which stood out a purple serrated mass on our left, and here we saw for the first time for many a month rain clouds piling up above the rocky heights. their tops, catching the rosy glow from the declining sun, appeared in their quaint forms like loftier mountains with their snowy summits all aglow. this was, indeed, a grateful sight to us; the camels already pricked up their ears, for the smell of moisture was in the air. we knew that the end of our waterless journey was not far off; for where those clouds were discharging their precious burdens the valley of ariab lay. but many a weary ridge of black rock and agaba must still be crossed before our goal was reached. we camped at six that evening till midnight, when we started on our record march. unfortunately at this time my filter gave out, owing to the perishable nature of the rubber tubing; the remaining water in our girbas was foul and nauseating from the strong flavor of the skins. i resolved to try and hold out without touching the thick, greasy fluid, and wait till the wells of ariab were reached. as we advanced, the signs of water became more and more apparent; the camel grass was greener down by the roots, and mimosa and sunt trees flourished at every few hundred yards. when morning came, for the first time we heard the chirruping and piping of birds. the camels increased their pace, and all became eager to reach our destination before the extreme heat of the day. but pass after pass was traversed, and valley after valley crossed, and yet the wadi of ariab, with its cool, deep wells of precious water, was still afar. it was not till past two o'clock in the afternoon that a long, toilsome defile of rugged rock brought us on the edge of a steep descent, and before us lay the winding khor of ariab, with its mass of green fresh foliage throwing gentle shadows on the silver sand of its dry watercourse. it seemed an age as we traversed that extended khor before our guide pointed to a large tree on our right, and said "moja." we dismounted under the shadow of its branches, and found awaiting us the sheikh of the valley, who pressed our hands and greeted us in a most friendly way; but i was almost mad with thirst, and asked for the well. i was taken to a mound a few yards from our retreat, on the sides of which were two or three clay scoop-outs, all dry but one, and this held a few gallons of tepid water, from which camels had been drinking. the man took a gourd, half filled it, and offered it to me to drink. "but the well, the well!" i cried. "oh! that's a little higher up," said he, and he led me to a wide revetted well about fifty feet deep, at the bottom of which, reflecting the sky, shone the water like a mirror. "that's the water i want," said i. the man shook his head. "you cannot drink of that till your baggage camels arrive; we have no means of reaching it." i almost groaned aloud, and with the agony of the ancient mariner could well cry, "water, water everywhere, but not a drop to drink." there was no help for it. i made my way back to the shadow of the tree, threw myself on my blanket, and, racked with thirst, tried to wait patiently for the coming of the camel men. fortunately, the sheikh of the well was inspired with hospitality, and after a while brought us some fresh milk in a metal wash basin, a utensil which he evidently produced in honor of our visit. i took a long draught, and though it was associated with native ablutions, i shall always remember it with the greatest satisfaction. we camped for hours in the sylvan vicinity of ariab wells--stretched ourselves in the broad shadows of its mimosa trees, and drank of and bathed in its sweet, cool waters. this long rest improved our camels wonderfully. by the bye, there was much speculation between two of our party regarding the behavior of these curious animals on arriving at the wells after their long waterless march. a general impression was that for the last few miles the camels would race for the waters, and thwart all endeavors to hold them in. my experience of the strange beast was otherwise, and subsequent events proved that i was right. when the hamleh, as we christened our caravan, arrived, the camels quietly waited awhile after their burdens were taken from their humps. then, as if an afterthought had struck them, they slowly approached the scoop-outs and with the most indifferent air would take a mouthful of the liquid, then, stiffening their necks, they would lift their heads and calmly survey the scenery around them, till their drivers would draw their attention to the fact that there was at least another draught of water in the pool. it should be remembered that these animals had just come off a continuous journey of nearly fifteen hours, without a halt, and had been for three whole days without water. we left our camping ground as the sun began to dip behind the hills shutting in the khor. our way now lay in a more northeasterly direction, and the sun threw the hills and valleys we were approaching into a marvelous medley of glorious color, and more than one of us regretted that we had not brought our color boxes with us. sometimes we seemed to catch a glimpse of the heather-clad highlands of scotland. then a twist in the khor we were traversing suggested the rugged passes of afghanistan. gazelle and ariel stole among the foot hills or stood gazing at us as near as a stone's throw. one of our party, mr. gwynne, commenced stalking a gazelle, but, darkness setting in, the beast got away. for the rest of the journey to suakim, however, he had good sport, and saved us many a time from going hungry with his shooting for the pot. about miles from ariab we came to one of the most interesting spots of the whole journey--the extensive valley of khokreb, wherein lay the deserted dervish dem, or stronghold. here some followers of osman digna used to levy toll on all caravans and persons moving toward suakim, or taking routes south. the dem consisted of a number of well built tokuls, or straw huts, standing in their compounds, with stabling for horses and pounds for cattle. the whole was surrounded with a staked wall, in front of which was a zariba of prickly mimosa bush, to stop a sudden onrush of an enemy. the place was intact, but there was not a living soul within it, or in the vast valley in which it stood, that we could see. in fact, our whole journey up to the present seemed to be through a country that might have been ravished by some plague or bore some fatal curse. as the light of the moon prevailed, we came upon an extensive plain shelving upward toward steep hills. specks of bright light stood out against the distant background, and we presently found that the moonlight was glinting on spear heads, and soon a line of camels crept toward us, and marching as escort was a small guard of hadendowahs, with spear and shield. we found the convoy to be a detachment of a caravan of camel loads of stores sent from suakim to berber by that enterprising greek, angelo, of the former town. they had been on the road already eight days, having to move cautiously owing to rumors of dervish activity, but had arrived so far safely. we bivouacked for several hours in the wadi of salalat, which was quite parklike with its fine growth of sunt trees. when we had crossed the frontier between bisheren and hadendowah country we were in comparative safety regarding any molestation by the natives, for we were escorted by the son of the sheikh of one of the subtribes of the latter country. at all events, i must have been a sore temptation for any evil disposed fuzzy wuzzy; for, owing to my camel being badly galled by an ill-fitting saddle, i would find myself for many hours entirely alone picking my way by the light of the moon, the poor brute i was riding not being able to keep pace with the rest. all the following day our route lay over stony plains of a bolder type than any we had yet seen, and when in the heart of the hadendowah hills we came suddenly upon a scene in its weirdness the most extraordinary and most appallingly grand i had ever seen. a huge wilderness lay before us like the dry bed of a vast ocean, whose waters by some subterranean convulsion had been sucked into the bowels of the earth, leaving in its whirling eddies the debris of submarine mountains heaped up in rugged confusion or scattered over its sandy bottom. porphyry and black granite bowlders, in every conceivable form and size, lay strewn over the plain. sometimes so fantastic did their shapes become that the least imaginative of our party could picture the gigantic ruins of some mighty citadel, with its ramparts, bastions and towering castle. for many hours we were traversing this weird and desolate valley, and when the sun cast long shadows across our track as he sank to rest, his ruddy light falling upon the dark bowlders, polished with the sand storms of thousands of years, stray pieces of red granite would catch his rosy glint, and sparkle like giant rubies in a setting of black pearls. we found more life in ten miles of the hadendowah country than during the whole of the first part of our journey. flocks of sheep, goats and oxen passed us coming to the wells, or going to some pasturage up in the hills, but few natives came near us, and there were no signs of habitation anywhere. the wells we now passed were mere water holes similar to those met with up country in australia. the flocks of the natives would hurry down at eventide and drink up all the water that had percolated through the sand during the day, befouling the pools in every conceivable way. natives seem to revel in water contaminated by all kind of horrors. they wash the sore backs of their camels, bathe their sheep and drink from the same pool. at one large hole round which a number of natives were filling their girbas we halted, and procured some of the liquid, which was muddy and tepid, but wholesomer. a native caravan had camped near by and the hadendowah escort of spearmen crowded round us. the fuzzy wuzzy is a much more pleasant object when seen through a binocular than when he is close to you. his frizzy locks are generally clotted with rancid butter, his slender garment is not over clean. he is a very plucky individual, as we know, thrifty, and lives upon next to nothing, but many live upon him. several graybeards came up to salute their sheikh, who was traveling with us, and this they did by pressing his hand many times, and bowing low, but they glanced at us with no amiable eyes, and suddenly turned away. there was no absolute discourtesy; they simply did not want to be introduced. probably they remembered the incident at tamai, where many of their friends were pierced with british bullets. so they slung their shields, trailed their spears and turned away. my camel had much improved by gentle treatment and i was able to ride on ahead. just as i neared the narrow neck of the tamai pass, two men and a boy climbed down toward us from a small guard house, on a lofty rock to our left. my camel man and i instinctively came to a halt, for the manner of the comers, who were fully armed, was impressive. they confronted us and immediately began questioning my camel man, after much altercation, during which i quietly leaned over my saddle and unbuttoned my revolver case, for they looked truculent and somewhat offensive. my camel man mysteriously felt about his waist belt, and eventually handed something to the foremost native, whereat he and his companions turned and began to reclimb the hill. as we went on our way, i inquired the reason of the men barring our path. "oh," my man said, "it is simply a question of snuff." "snuff," i exclaimed, in astonishment. "yes; that was all they wanted--a little tobacco powder to chew." here was a possible adventure that seemed as if it were going to end in smoke, and snuff was its finale. after all the suakim-berber road, that was looked upon as full of dramatic incident--for even our military friends in berber, when they bid us goodby, said, "it was a very sporting thing to do. great scott! they only wished they had the luck to come along"--was a highway without even a highwayman upon it, and apparently for the moment as pleasantly safe, minus the hostelries en route, as the road from london to york. prom the top of tamai pass, , feet--though of the same name, not to be confounded with the famous battle which took place further south--we began to make a rapid descent, and the last sixty miles of our journey were spent in traversing some of the most lovely mountain scenery i think i have ever visited. sometimes one might be passing over a yorkshire moorland, with its purple backing of hills, for the sky was lowering and threatened rain. then the scene would as quickly change to a swiss valley, when, on rounding the base of a spur, one would strike a weird, volcanic-torn country whose mountains piled up in utter confusion like the waves of the stormy atlantic; and further on we would come out upon a plain once more scattered with gigantic bowlders of porphyry and trap, out of which the monoliths of ancient thebes might have been fashioned. on the morning of the tenth day out from berber, we sighted the fort and signal tower of the egyptian post at tambuk, on a lofty rugged rock, standing out in the middle of an immense khor. this was practically the beginning of the end of our long journey, and here we rested a few hours, once more drinking our fill of pure sparkling water from its revetted wells. about half an hour in a northeasterly direction, after a continual descent from the egyptian fort, we noticed, at intervals between the hills in front of us, a straight band of blue which sparkled in the sunlight. at this sight i could not refrain from giving a cheer--it was the red sea that glistened with the sun--for it meant so much to us. across its shining bosom was our path to civilization and its attendant comforts, which we had been denied for many a month. night found us steadily descending to ward the seaboard, as we neared otao, in the vicinity of which we were to bivouac for the night. my camel nearly stumbled over an old rusty rail thrown across my path, and further on i could trace in the moonlight the dark trail of a crazy permanent way, with its rails all askew. we were passing the old rail head of the suakim-berber railway, that was started in . i wondered, as i followed fifteen miles of this rusty line, a gradual slope of , feet toward the sea, whether the road i had only just traversed had ever been surveyed for a railway, and whether anybody had the slightest notion of the difficulties to be contended with in carrying out the scheme. of course, modern engineering, with such men as sir benjamin baker at the fore, can overcome any difficulty if money be no object, but who can possibly see any return for the enormous outlay an undertaking of this kind would entail? to start with, there is one up grade of , feet within forty miles from suakim, and the khors, through which the railway must wind, are sometimes raging torrents. to obviate this, if the line be built of trestles (timber elevations), as with the canadian pacific railway, there is no wood in the country but for domestic purposes. material, for every detail, must be imported. a smaller matter, but also somewhat important--though water apparently can be found in the khors for the digging, it is a question whether a sufficient quantity can be got at all times for the requirements of a railway. the natives themselves are often very badly off for water, as in the case of the obak wells. wells run dry at odd times in this country, and can never be depended upon. of course, water can be condensed at suakim and stored. further, a rival line is already in progress, which will connect wady halfa with berber early this year. european goods coming by that line from alexandria would be free of the suez canal dues, and certainly the directors of that line would treat freights favorably if suakim should ever be connected with berber by rail. as for the interior trade of the country, nearly all the population have either died from recent famine or have been killed off in the mahdi's cause. there is no commercial center or even market to tap from one end of the road to the other. the next morning we came in view of suakim, the city of white coral, with her surf-beaten opalesque reefs stretching as far as the eye could follow. it seemed strange to me to be peacefully moving toward her outlying forts, for when i was last in her vicinity one could not go twenty yards outside the town without being shot at or running the gauntlet of a few spears. but here i was, slowly approaching its walls, accompanied by some of the very men who in those days would have cut my throat without the slightest hesitation. suakim had changed much for the better; her streets were cleaner, and mostly free from oriental smells. but these sanitary changes always take place when british officers are to the fore. surgeon capt. fleming is the medical officer responsible for the health of the town, and he has been instrumental in carrying out great reforms, especially in doing away with the tokuls and hovels, in which the arabs herded together, and removing them to a special quarter outside the town. the principal feature about suakim to-day is its remarkable water supply. in our troops had to depend on condensed sea water, supplied from an old steamer anchored in the harbor, and the town folk drew an uncertain supply from the few wells outside the town. but now suakim never wants for water, and that of the best. she even boasts of a fountain in the little square opposite the governor's house. engineer mason is responsible for this state of efficiency, to which suakim owes much of her present immunity from disease. during the last twelve years immense condensing works have been erected on quarantine station; but, better still, about two years ago mr. mason discovered an apparently inexhaustible supply near gemaiza, about three miles from the town. there is a theory--which this water finding has made a possible fact--that as coral does not grow in fresh water, the channel which allows steamers to approach close up to the town, through her miles of coral reefs, is caused by a fresh water current running from the shore. however, on this theory mason set to work and found a splendid supply at fort charter; an excavation in the khor there, about feet long and deep, is now an immense cistern of sweet water, the result of which the machines condensing tons of water a day are now only required to produce one-half the quantity, saving the egyptian government a considerable outlay. the natives look upon mason as a magician, the man who turns the salt ocean into sweet water. but metal refuse, scraps of iron, old boiler plates, under his magic touch, are also turned into the most useful things. for instance, the steam hammer used in the government workshop is rigged on steel columns from the debris of an engine room of a wrecked vessel. the hammer is the crank of a disused shaft of a cotton machine, the anvil is from an old "monkey," that drove the piles for the suakim landing stage in ; the two cylinders are from an effete ice machine, and the steam and exhaust pipes come from a useless locomotive of the old railway. a lathe, a beautiful piece of workmanship, is fashioned out of one of the guns found at tamai. and the building which covers these useful implements was erected by this clever engineer in the sirdar's service, who had utilized the rails of the old suakim-berber line as girders for its roof, and, in my humble opinion, this is probably the very best purpose for which they can be used. * * * * * tapirs in the zoological garden at breslau. a fine pair of shabrack (tapirus indicus) and another pair of american tapirs (tapirus americanus) constitute the chief attraction of the house devoted to pachyderms in the zoological garden at breslau, and interest in this section of the garden has recently been greatly enhanced by the appearance of a healthy young shabrack. this is only the second time that a shabrack tapir has been born in captivity in europe, and as the other one, which was born in the zoological garden at hamburg, did not live many days, but few knew of its existence; consequently, little or nothing is known of the care and development of the young of this species, although they are so numerous in their native lands. farther india, southwestern china and the neighboring large islands, where they also do well in captivity. the tapir was not known until the beginning of this century, and even now it is a great rarity in the european animal market, and as the greatest care is required to keep it alive for any length of time in captivity, it is seldom seen in zoological gardens; therefore, the fact that the shabrack tapirs in the breslau garden have not only lived, but their number has increased, is so much more remarkable. [illustration: shabrack tapir with young one (five days old) in the breslau zoological garden. from drawing by erich suckow.] our engraving shows that the five days old tapir resembles its mother in form, although its marking is quite different. its spots and stripes are very similar to those of the young of the american tapir, several of which have been born in captivity in europe. they shade from yellow to brown on black or very dark brown ground, and the spots on the legs take a whitish tone. this little one's fur is longer on the body than on the head and extremities, and is soft and thick, but has not the peculiar glossiness of the full grown animal. its iris is a beautiful blue violet, while that of the old one is dark violet, and its little hoofs are reddish brown, while those of the mother are horn gray. when standing, the new comer measures about two feet in length and one foot two inches in height, having gained about one inch in height in five days. its fine condition is doubtless due partly to the great care given it and partly to the healthy constitution of the mother, and it is the pet of its keepers and of the public.--illustrirte zeitung. * * * * * the influence of scenery upon the character of man. the effect of scenery upon the mind of man has often been noticed and much has been written about it. illustrations of this are generally drawn from the historic lands and from the ancient people of the east. the civilized races, such as the greeks, romans and other nations who formerly dwelt on the coast of the mediterranean, are taken as examples. the greeks are said to have owed their peculiar character and their taste for art to the varied and beautiful scenery which surrounded them. their mythology and poetry are full of allusions to the scenes of nature. mountains and springs, rivers and seas all come in as the background of the picture which represents their character and history. the same is true of the romans, egyptians, phenicians, syrians, hebrews, the ancient trojans and carthaginians. each one of these nations seems to have been affected by scenery. they were all, with the exception of the carthaginians, confined within the limits of a narrow territory, and remained long enough in it to have partaken fully of the effect of their surroundings. the romans were warlike at the beginning, and bore the air of conquerors, but their taste for art and literature resembled that of the greeks. the egyptians were sensuous and luxurious people. their character bore the stamp of the river nile with its periodical overflow, its rich soil and mild climate. the type of their religion was drawn from the gods who inhabited the same river valley. the phenicians were a maritime people; they were the first navigators who reached the great seas. their gods resembled those of the assyrians and chaldeans, but their character resembled the seas over which they roved; they did not originate, but they transported the products and inventions of the ancient world. the hebrews had a national character which seemed to have been narrowed down to a small compass by their isolation and by their history, but their religion was as grand as the mountains of the desert, and their poetry as beautiful as the scenery along the river jordan, which ran as a great artery through their land. it was a holy land which gave impress to the holy book. the effect of scenery upon human character is also illustrated in the case of the ancient inhabitants of america. this land was isolated from the rest of the world for many centuries--perhaps for thousands of years. it is supposed that up to the time of the discovery the tribes were permanent in their seats. each tribe had its own habitat, its own customs, its own mythology and its own history. the effect of scenery must be considered, if we are to understand the peculiarities which mark the different tribes. some imagine that the indians are all alike, that they are all cruel savages, all given to drunkenness and degradation and only waiting their opportunity to wreak their vengeance upon helpless women and children. those who know them, however, are impressed with the great variety which is manifest among them, and are especially convinced that much of this comes from the scenery amid which they have lived. the eastern tribes may have had considerable sameness, yet the algonquins, who were the prairie indians, and the iroquois, who dwelt in the forest and amid the lakes of new york, differed from one another in almost every respect, and the sioux and dakotas, who were also prairie indians, differed from both of these. they were great warriors and great hunters, but had a system of religion which differed from that of any other tribe. the sioux were cradled amid the mountains of the east, and bear the same stamp of their native scenery. they resemble the iroquois in many respects. the same is true of the cherokees, who were allied to the iroquois in race and language. they were always mountain indians; but the southern tribes were very different from either. they were a people who were well advanced in civilization so far as the term can be applied to the aborigines. their skulls are without angles and differ greatly from the keel-shaped skulls. they were dolichocephalic rather than kumbocephalic. they resemble the polynesians, while the northern tribes resembled the mongolians. whatever their original home was, their adopted habitat was in accord with their tastes and character. it did not change them but rather made their traits more permanent and stable. the tribes of the northwest coast were seafarers; they inhabited the forest and worshiped the animals which were peculiar to the forest and took as their totems the eagle, wolf and raven, but they drew their subsistence in great part from the sea. they worshiped the animals of the seas, such as the shark, the whale and the sculpin. their skill and courage as navigators have never been equaled. taking their families and the few articles of commerce gathered from the forest they entered the symmetrical and beautifully carved canoes and breasted the storms and waves of the great sea near which they lived. there was a wildness in the waves which just suited them. the sea brought out the best traits and developed the heroic character. they were the "sea kings" of the northwest. they were great navigators and great hero worshipers. the tribes of the interior, the pueblos, the zunis, differed from all other tribes. they were surrounded by wild tribes, such as the apaches, comanches and navajoes. whatever their origin, they had remained long enough in this territory to be affected by the scenery and surroundings. they were mild, luxurious, given over to religious ceremonies, made much of mythology and had many secret societies. they built their terraced houses, taking the cliffs and mesas as their patterns, and made them so similar to the rock and cliffs that it was difficult to recognize them at a distance. they did not mould the mountains into villages as the mayas did, but they made their houses to conform to the mountains, and took the mountain gods and their nature divinities as chief objects of worship. the contrast between the ancient tribes of this region and the wild tribes which intruded upon them was very great. the navajoes were a mountain people and drew their religion from the mountains. they borrowed many myths and customs from the ancient pueblos, and like them, settled down to an agricultural life; but their sand paintings and their ceremonies reveal a taste for art and a poetical imagination which are very remarkable. the lone indian who places his wigwam in the midst of the mountains seems to be always a stranger. the scenery has no effect upon him. it makes his spirit sad and his music plaintive, for he breathes out his spirit in his music. he never has had and never will have the character which some of his ancestors cultivated amid the wild scenes. his race is doomed; his fate is sealed. he can never catch up with the progress of the time. the railroad is bound to take the place of the indian trail; the miners' cabin must supplant the indian wigwam. great cities will rise near where ancient villages stood, but the savage fails to appreciate the thought or the character of the people who have supplanted him. the wigwam amid the mountains is a symbol of what he is, but the locomotive at its side is an emblem of progress and of promise to those who will use their opportunities. the mountains are in the background--they suggest the possibilities which are before the settler. they interpose barriers, but the barriers themselves are fraught with good influences. freedom has always dwelt among the mountains. reverence for the almighty has also prevailed. the leveling process must cease and man become more elevated in his thoughts as he rises to the altitude of these great heights.--the american antiquarian. * * * * * a novel way of riding a bicycle. "artists" of the variety stage and the circus are always trying to find something new, for the same old trapeze performances, trials of strength, performances of rope dancers, etc., have been presented so many times that anyone who invents an entirely new trick is sure of making a large amount of money out of it; the more wild and dangerous it is, the better. anything that naturally stands on its feet but can be made to stand on its head will be well received in the latter attitude by the public. some such thought as this must have been in the mind of the man who conceived the idea of riding a bicycle on the ceiling instead of on the floor. the "trick" originated with the swiss acrobat di batta, who, being too old to undertake such a performance himself, trained two of his pupils to do it, and they appeared with their wheel in busch circus in berlin. the wheel, of course, ran on a track from which it was suspended in such a way that it could not fall, and the man who operated it used the handle bar as he would the cross bar of the trapeze. one would think that the position of the rider was sufficiently dangerous to satisfy any public, but the inventor of the trick sought to make it appear more wonderful by having the rider carry between his teeth a little trapeze from the crosspiece of which another man hung. [illustration: bicyclist riding from the ceiling of a circus.] different colored lights were thrown on the performers as they rode around the ceiling, and at the end of the performance first one and then the other dropped into the safety net which had been placed about sixty feet below them. we are indebted to the illustrirte zeitung for the cut and article. * * * * * requirements of palestine explorer. lieut.-col. conder says that the requirements for exploration demand a knowledge not only of syrian antiquities, but of those of neighboring nations. it is necessary to understand the scripts and languages in use, and to study the original records as well as the art and architecture of various ages and countries. much of our information is derived from egyptian and assyrian records of conquest, as well as from the monuments of palestine itself. as regards scripts, the earliest alphabetical texts date only from about b. c., but previous to this period we have to deal with the cuneiform, the egyptian, the hittite and the cypriote characters. the explorer must know the history of the cuneiform from b. c. down to the greek and roman age, and the changes which occurred in the forms of some characters originally hieroglyphics, but finally reduced to a rude alphabet by the persians, and used not only in babylonia and assyria, but also as early as b. c. in asia minor, syria, armenia, palestine and even by special scribes in egypt. he should also be able to read the various egyptian scripts--the hieroglyphics of the monuments, the hieratic, or running hand of the papyri, and the later demotic. the hittite characters are quite distinct, and number at least characters, used in syria and asia minor from b. c. or earlier down to about b. c. the study of these characters is in its infancy. the syllabary of cyprus was a character derived from these hittite hieroglyphics, and used by the greeks about b. c. it includes some fifty characters, and was probably the original system whence the phenician alphabet was derived. as regards alphabets, the explorer must study the early phenician and the hebrew, samaritan and moabite, with the later aramean branch of this alphabet, whence square hebrew is derived. he must also know the ionian alphabet, whence greek and roman characters arose, and the early arab scripts--palmyrene, nabathean and sabean, whence are derived the syriac, cufic, arabic and himyaritic alphabets. as regards languages, the scholars of the last century had to deal only with hebrew, aramaic, syriac, coptic and greek, but as the result of exploration we now deal with the ancient egyptian whence coptic is derived, and with various languages in cuneiform script, including the akkadian (resembling pure turkish) and the allied dialects of susa, media, armenia and of the hittites; the assyrian, the earliest and most elaborate of semitic languages; and aryan tongues, such as the persian, the vannic and the lycian. the art and architecture of western asia also furnish much information as to religious ideas, customs, dress and history, including inscribed seals and amulets, early coins and gems. the explorer must also study the remains of greek, roman, arab and crusader periods, in order to distinguish these from the earlier remains of the canaanites, phenicians, hebrews, egyptians and assyrians, as well as the art of the jews and gnostics about the christian era, and the later pagan structures down to the fourth century a.d.--nature. * * * * * the neutral use of cables. eleven submarine cables traverse the atlantic between and degrees north latitude. nine of these connect the canadian provinces and the united states with the territory of great britain; two (one american, the other anglo-american) connect france. of these, seven are largely owned, operated or controlled by american capital, while all the others are under english control and management. there is but one direct submarine cable connecting the territory of the united states with the continent of europe, and that is the cable owned and operated by the compagnie francais cables telegraphiques, whose termini are brest, france, and cape cod, on the coast of massachusetts. all these cables between and degrees north latitude, which unite the united states with europe, except the french cable, are under american or english control, and have their termini in the territory of great britain or the united states. in the event of war between these countries, unless restrained by conventional act, all these cables might be cut or subjected to exclusive censorship on the part of each of the belligerent states. across the south atlantic there are three cables, one american and two english, whose termini are pernambuco, brazil, and st. louis, africa, and near lisbon, portugal, with connecting english lines to england, one directly traversing the high seas between lisbon and english territory and one touching at vigo, spain, at which point a german cable company has recently made a connection. the multiplication under english control of submarine cables has been the consistent policy of great britain, and to-day her cable communications connect the home government with all her colonies and with every strategic point, thus giving her exceptional advantages for commercial as well as for political purposes. the schedule blanks of rates of the english companies contain the following provisions: "the dispatches of the imperial government shall have priority when demanded. the cable must not, at any station, employ foreigners, and the lines must not pass through any office or be subject to the control of any foreign government. in the event of war, the government (of great britain) may occupy all the stations on english territory or under the protection of great britain, and it may use the cable by means of its own employes." it is not a pleasing reflection that in the actual situation the united states is at a great and embarrassing disadvantage. meanwhile it would seem to be the policy of the united states to overcome this disadvantage by the multiplication of submarine cables under american or other than english competing foreign ownership and control. although somewhat indeterminate, the policy of the united states in respect to the landing of foreign submarine cables, so far, at least, as the executive branch of the government is concerned, appears to be based chiefly upon considerations that shall guard against consolidation or amalgamation with other cable lines, while insisting upon reciprocal accommodations for american corporations and companies in foreign territory. the authority of the executive branch of the government to grant permission is exercised only in the absence of legislation by congress regulating the subject, and concessions of the privileges heretofore have been subject to such further action by congress in the matter as it may at any time take. several bills are now pending in congress relating to the landing of foreign submarine telegraph cables within the united states, and regulating the establishment of submarine telegraphic cable lines or systems in the united states. as this article is going to press, it is reported that the president has refused permission to a foreign cable company to renew a cable terminus within the territory of the united states, and that the question raised as to the power of the federal government to deny admission to the cable will be referred to the attorney-general for an opinion. meanwhile, the executive branch of the government holds to the doctrine that, in the absence of legislation by congress, control of the landing and operation of foreign cables rests with the president. the question of the landing of foreign cables received some consideration from the late attorney-general, in connection with an injunction suit brought by the united states against certain corporations engaged in placing on the coast of new york a cable having foreign connection. and he suggested for the consideration of congress whether it would not be wise to give authority to some executive officer to grant or withhold consent to the entry of such foreign enterprises into this country on such terms and conditions as may be fixed by law. the principal and most important submarine cables traversing or connecting the great oceans are owned and operated by private corporations or companies. they are in number , and their length in nautical miles is , . the length of cables owned or operated by state governments is, in nautical miles, , . the policies of states, the movements of fleets and armies, and the regulation of the markets of the commercial world, depend upon devices, communications and orders that are habitually transmitted through the agency of submarine cables. in this view, the first aim is to safeguard from wanton destruction the delicate and expensive mechanism of these cables; the second is to restrain within the narrowest limits practicable interruptions in the operation of cables, even in the midst of hostilities; and the third is to encourage the establishment and extension of submarine cables owned and operated by american capital. all these ends may be advanced by the agreement of the powers to neutralize absolutely the submarine cable systems of the world. to do this will be a step in the direction of extending international jurisdiction, which is to be a controlling feature of the new periodical about to be established at berlin, and to be printed in german, french and english, under the name of "kosmodike." --alexander porter morse in the albany law journal. * * * * * park making. those who make public parks are apt to attempt too much and to injure not only the beauty, but the practical value of their creations by loading them with unnecessary and costly details. from the time when landscape gardening was first practiced as a fine art to the present day, park makers have been ambitious to change the face of nature--to dig lakes where lakes did not exist and to fill up lakes where they did exist, to cut down natural hills and to raise artificial ones, to plant in one place and to clear in another, and generally to spend money in construction entirely out of proportion to the value of the results obtained. the best art is simple in its expression, and the highest form of art in gardening is perhaps that which, taking advantage of such natural conditions as it finds, makes the best of them with the smallest expenditure of labor and money. simplicity of design means not only economy of construction, but, what is of even more importance, economy of maintenance. the importance of making it possible to keep a great park in good condition without excessive annual expenditures for maintenance is a simple business proposition which would not seem to require much demonstration. yet park makers, with their unnecessary walks and drives; with their expensive buildings which are always getting out of repair; their ponds, in which there is rarely water enough to keep them fresh; their brooks, which are frequently dry; their elaborate planting schemes, often ill suited to the positions where they are wanted, make parks expensive to construct and impossible to maintain in good condition, especially in this country, where the cost of labor is heavy and there is difficulty in obtaining under existing municipal methods skilled and faithful gardeners to keep anything like an elaborate garden in good condition. the most superficial examination of any of our large urban parks will show that wherever elaborate construction and planting have been attempted they have failed from subsequent neglect to produce the effects expected from them, and that broad, quiet, pastoral and sylvan features are the only permanent and really valuable ones we can hope to attain in our great city parks. it is needless, perhaps, to repeat what has been said so often in the columns of this journal, that in our judgment the greatest value and only justification of great urban parks exist in the fact that they can bring the country into the city and give to people who are obliged to pass their lives in cities the opportunity to enjoy the refreshment of mind and body which can only be found in communion with nature and the contemplation of beautiful natural objects harmoniously arranged. parks have other and very important uses, but this is their highest claim to recognition. if it is the highest duty of the park maker to bring the country into the city, every road and every walk not absolutely needed to make the points of greatest interest and beauty easily accessible is an injury to his scheme, and every building and unnecessary construction of every kind reduces the value of his creation, as do trees and shrubs and other flowering plants which are out of harmony with their surroundings. such things injure the artistic value of a park; they unnecessarily increase its cost and make the burden of annual maintenance more difficult to bear. simplicity of design often means a saving of unnecessary expenditure, but it should not mean cheapness of construction. the most expensive parks to maintain are those which have been the most cheaply constructed, for cheap construction means expensive maintenance. roads and walks should not be made where they are not needed, and they should not be made unnecessarily wide to accommodate possible crowds of another century, but those that are built should be constructed in the most thorough and durable manner possible, in order to reduce the cost of future care. when lawns are made, the work should be done thoroughly; and no tree or shrub should be planted in any manner but the best and in the most carefully prepared soil. only as little work as possible should be done, but it should be done in the most permanent manner. the best investment a park maker can make is in good soil, for without an abundance of good soil it is impossible to produce large and permanent trees and good grass, and the chief value of any park is in its trees and grass; and if the money which has been spent in disfiguring american parks with unnecessary buildings and miscellaneous architectural terrors had been used in buying loam, they would not now present the dreary ranks of starved and stunted trees and the great patches of wornout turf which too often disfigure them. only the hardiest trees and shrubs should be used in park planting; for there is no economy in planting trees or shrubs which are liable to be killed any year, partially, if not entirely, by frost or heat or drought, which annually ruin many exotic garden plants, nor is it wise to use in public parks plants which, unless carefully watched, are disfigured every year by insects. it costs a great deal of money to cut out dead and dying branches from trees and shrubs, to remove dead trees and fight insects, but work of this sort must be done, unless the selection of plants used to decorate our parks is made with the greatest care. fortunately, the trees and shrubs which need the least attention, and are therefore the most economical ones to plant, are the best from an artistic point of view; and to produce large effects and such scenery as painters like to transfer to canvas, no great variety of material is needed. the most restful park scenery, and, therefore, the best, can be obtained by using judiciously a small number of varieties of the hardiest trees and shrubs, and the wise park maker will confine his choice to those species which nature helps him to select, and which, therefore, stand the best chance of permanent success. no park can be beautiful unless the trees which adorn it are healthy, and no tree is healthy which suffers from uncongenial climatic conditions and insufficient nourishment. even if they are not inharmonious in a natural combination, the trees and shrubs which need constant pruning to keep them from looking shabby are too expensive for park use and should, therefore, be rejected when broad, natural effects in construction and economy of maintenance are aimed for by the park maker. the sum of the matter of park construction is to make rural city parks less pretentious and artificial in design and to so construct them that the cost of maintenance will be reduced to the minimum. this will save money and lessen the danger of exhibitions of bad taste and encourage that simplicity which should be the controlling motive of sincere art.--garden and forest. * * * * * influence of ocean currents on climate. few people realize that a very large part of inhabited europe lies to the north of the latitude which in this country is considered the limit of habitation, says prof. ralph s. tarr, in the independent. london is situated in the same latitude as southern labrador, where the inhabitants are scattered in small villages and are mainly summer residents who come there from the more southern lands to engage in fishing. during the winter their ports are closed by ice and navigation is stopped, while toward the british isles steamers are constantly plying from all directions. the great city of st. petersburg, which in winter is inaccessible to ships, but in summer enjoys a moderate climate, lies in the same latitude as the northern part of labrador, where snow falls in every month of the year and where floating ice frequently retards navigation even in midsummer. as a result of the severity of climate the only people who find northern labrador a place fit for existence are the eskimo tribes, who win their living under great difficulties almost entirely from the sea. no white men live there, with the exception of some missionaries and the occasional traders. everyone knows full well the reason for this difference in the climates of the two lands; the european coasts receive constant supplies of water that has been warmed in southern latitudes and carried northward in the great oceanic circulation and particularly in the gulf stream. the west winds, blowing toward the european coast, carry from this warm ocean belt air with higher temperature than that which exists over the land. on the eastern side of the atlantic in place of a warm ocean current there is the cold labrador current, which blows from the north and chills the water of the northwestern atlantic. therefore, the winds that come from the ocean blow over water that has been cooled, and the prevailing winds, which are from the west, come over the land, which is cool in winter and warm in summer. one may see these differences in climate and the causes for them even more strikingly exhibited within the arctic belt than in this case which has been mentioned. the great land area of greenland, with an area of six or seven hundred thousand square miles, is a highland capped over the greater part of its area with a snow field which completely buries all the land excepting that near the margins. the tongues from this ice field, whose area is some , square miles, reach into the sea and furnish innumerable icebergs that float away, chilling the waters. notwithstanding the immense area of ice, the summer climate of the greenland coast is remarkably moderate, even as far north as melville bay. the reason for this is the same as that mentioned for the climatic peculiarities of europe. a current from the south, probably an eddy from the gulf stream, carries water northward along the greenland coast, thus raising the temperature so that the ice which forms in the sea water and the bergs which float upon its surface are made to disappear during the warm part of the year. sailing from the coast of greenland at about the middle point, near disco island, in the early part of september, one leaves a land with a delightfully pleasant climate and warmth almost like that of the early autumn of temperate latitudes, and proceeding south-westward across davis straits to baffin land, two or three hundred miles southward, there finds himself in the midst of the conditions of early winter. the greenland coast is not snow covered, plants are still in blossom and the hum of insects is heard; but in this more southern latitude, on the american side, the summer insects have entirely disappeared, only a few belated flowers are seen in protected places and a thin coat of snow covers all the land. light snow may fall here during any time of the summer; but in spite of these differences baffin land is not ice covered, while greenland is. the ice cap of the interior of greenland is present less because of the severity of the climate at sea level than from the fact that the air which reaches this land has become humid in crossing the water areas, and further in the fact that the interior is a highland. on the baffin land side the interior is less elevated and there is less water to the westward in the direction from which the prevailing winds blow. * * * * * causes of poverty.[ ] [footnote : report of richmond mayo smith, franklin h. giddings, and fred. w. holls, committee on statistics of the new york charity organization society.--condensed for public opinion.] the most interesting, and at the same time the most difficult, problem connected with an analysis of cases is to determine the real cause of destitution. it requires great experience and intelligence on the part of workers in charity to give even approximately the fundamental reason why a certain family has come to destitution. to classify cases from records without personal knowledge of each case, and then simply to count the cases, is a very inadequate method of arriving at the truth. the primary difficulty, of course, is to reach a classification. the one adopted by mr. warner in his book on american charities is: . causes indicating misconduct; . causes indicating misfortune. under the first head come drink, immorality, laziness, shiftlessness and inefficiency, crime and dishonesty, a roving disposition. under the second head come lack of normal support, matters of employment, matters of personal capacity, such as sickness or death in family, etc. the trouble with such a classification is that one cause may lie behind another, as drink is often the cause of lack of employment, of sickness or accident. on the other hand, lack of employment may lead to drink, immorality or laziness. with the limited number of cases that have been analyzed in this investigation, it would be impossible to expect any very conclusive results. we have endeavored, however, to make up for the small amount of the material by a careful and intelligent analysis, and by approaching the subject from three different points. we have first taken the alleged cause of distress--that is, the reason assigned by the person applying for relief. this, of course, will present the most favorable side, and the one most calculated to excite sympathy. we have, secondly, tabulated the real cause of distress, as gathered by the tabulator from the whole record. this, of course, is the judgment of an outside party, and the emphasis will be laid upon misfortune or misconduct according to the disposition of the investigator. we have, thirdly, the character of the man and woman as gathered from the record. this is supplementary evidence as to the real cause of distress. we go on now to present these three points of view. loss of employment, ; sickness or accident, ; intemperance, ; insufficient earnings, ; physical defect or old age, ; death of wage earner, ; desertion, ; other causes and uncertain, ; total, . an attempt was made to follow the example of mr. booth and introduce supplementary causes as well as principal causes. about the only result, however, is that sickness often accompanies loss of employment, and that loss of employment often accompanies sickness or accident. it is clearly seen in this whole table how disposed applicants for relief are to attribute their distress to circumstances beyond their control. in the following table we have an attempt to analyze the real cause of distress, according to the judgment of the tabulator as gathered from the full record. in chronic cases the same cause is apt to appear in the successive applications. it was thought that this might lead to undue accumulation of particular causes. a separate tabulation, therefore, was made for the first applications, and then for the total-- applications. the table is as follows: the real cause of distress. first applications. total applications. number. percent. number. per cent. lack of employment. . . sickness or accident. . . physical defects or old age. . . death of wage earner. . . desertion . . intemperance . . shiftlessness . . no need . . total . . in this table it will be seen that emphasis is laid on misconduct rather than on misfortune. the difference between the two sets of returns is obvious. where lack of employment and sickness have been alleged as accounting for - / per cent. of the total, they are believed by the tabulator to really account for only - / per cent. on the other hand, intemperance comes in as the real cause in - / per cent.; shiftlessness in - / per cent. of the applications, and in - / per cent. of the applications it was judged that there was no real need. it is very probable that these judgments are severe, but the result shows how frequently, at least, the personal character is a contributory cause of poverty. an attempt was made when reading the records to determine the general character of the man and woman--that is, the adult members of the family. such classification is at the best very rough, and does not give us much information. it may be said that the character was put down as good unless something distinctly to the contrary appeared. the results are given in the following table: personal character of man and woman. male. female. total. percentage. good criminal insane .. .. intemperate shiftless suspicious untruthful uncertain total "shiftless" includes male. female. total. professional beggers loss of independence lack of push laziness .. extravagance .. "worthless" prostitute .. total shiftless indefinite total it would seem from this table that the judgment of the investigators was lenient. in nearly one-half of the cases the character of the men and women was said to be good. * * * * * fire tests of cast iron columns, made by order of the city authorities of hamburg, are described in recent issues of the deutsche bauzeitung. the columns were feet inches long, . inches in diameter and of / inch or . inch metal. they were loaded centrally and eccentrically, and some were cased with a fireproof covering. a hydraulic press was placed below the column and its crosshead above it, and then a hinged oven containing twelve large gas burners was clamped about the column. the oven was furnished with apparatus for measuring heat, with peep holes and with a water jet. on an average a load of . tons per square inch, with a heat of , ° f., produced deformation in thirty-five minutes in a centrally loaded column without casing. this showed itself by bulging all round in the middle of the heated part, especially where the metal happened to be thinner; fracture occurred finally in the middle of the thickest point of the bulge. if the load was less, this occurred at a higher temperature. jets of water had no effect until deformation heat was reached. the casings had the effect of increasing the time before deformation began from half an hour to four or five hours. * * * * * engineering notes. the massilon (ohio) bridge company has received an order for the construction of a cantilever bridge feet long and feet wide, which is to be built by the new york dredging company at honda, on the magdalena river, in colombia, south america. navigation on the amoo-darya is to be extended considerably, so that russian steamers will proceed upward on that river to feisabad-kalch, which is only about miles from the scene of the recent indian frontier troubles.--uhland's wochenschrift. a new process of manufacturing artificial stone has been patented in england. the stone is formed in steel moulds, which can be adjusted to any size, shape or design for which the finished stone may be required, and solid blocks weighing several hundred pounds have been easily produced. m. berlier, the well known engineer, has laid before the governments of spain and morocco a project for the construction of a tunnel under the straits of gibraltar. the execution of this plan would have immense economic consequences, so that its fate will be followed with interest. m. berlier is the inventor of a new method of subterranean boring. "the sale of the steamers 'pennsylvania,' 'ohio,' 'indiana,' 'illinois,' and 'conemaugh,' by the international navigation company to the states steamship company for the pacific trade leaves but five steamships flying the american flag crossing the atlantic ocean," says the marine record. "they are the 'st. paul,' gross tons , . ; 'st. louis,' gross tons , . ; 'new york,' gross tons , . ; 'paris,' gross tons , . ; 'evelyn,' gross tons , . , the latter three built in english shipyards and denationalized." john murphy, general manager of the united traction company, of pittsburg, reports the average life of motor gears on his line as two years, and the average life of pinions, nine months. he is employing the gears and pinions of the simonds manufacturing company. the service is an exceedingly severe one, on account of the many grades on the line. the average life of trolley wheels is , miles, and the conditions under which they operate are quite severe, as the company has on its main line eighteen railroad crossings. a tempered copper wheel is employed. according to a recent correspondent of the buffalo express, in the pennsylvania oil region during the last year over gas engines have been placed on oil leases and are doing satisfactory work. the engines vary from to horse power. every big machine shop in the oil regions is turning out gas engines. the machine shops are also using gas engines to drive their own machinery. during the last year twenty of the standard oil company's pipe line pumping stations have been equipped with gas engines. in all the new stations and in old ones where new machinery is needed, the gas engine will be preferred. where natural gas cannot be had and coal was formerly burned, gasoline is used. the pumping station engines are all provided with electric ignition. in a recent issue of the railway age is published the following, based upon the last report of the interstate commerce commission: "last year the railways of the united states carried over , , , passengers one mile. they also carried , , , tons of freight one mile. the total amount paid in dividends on stock was $ , , --call it $ , , . of the total earnings of the railways, about per cent. came from freight service and per cent. from passenger service. let us assume, then, that of the $ , , paid in dividends, per cent., or $ , , , was profit on freight service and $ , , was profit on passenger service. let us drop fractions and call it $ , , from freight and $ , , from passengers. by dividing the passenger profit into the number of passengers carried ( , , , ), we find that the railways had to carry a passenger miles in order to earn $ of profit--or five miles to earn cent. their average profit, therefore, was less than two-tenths of cent for carrying a passenger (and his baggage) one mile. by dividing the freight profit into the freight mileage ( , , , ) we find that the railways had to carry one ton of freight , miles in order to earn $ , or over fifteen miles to earn cent. the average profit, therefore, was less than one-fifteenth of a cent for carrying a ton of freight (besides loading and unloading it) one mile." the railroads in the united states have cost about $ , per mile, and probably a considerable percentage of this has not entered into the construction of the railroads and the equipment of same, says "signal engineer" in the railroad gazette. the railroads of great britain have cost about $ , a mile, and yet we claim for the united states more luxurious travel than can be found in great britain; and this is true so long as the travel is safe. the difference in the cost of construction in the united states and england may be found in the item of safety appliances. the railroads of great britain carried during the last year , , passengers, with safety to all but five, and this was possible because the railroads, instead of expending their capital in luxurious equipment and passenger stations, chose rather to equip their lines with the most improved signaling and interlocking. the railroad companies of the united states in expending large sums for handsome and convenient terminals and luxurious cars are placing monuments before the public eye which naturally lead to the belief that every appointment of such roads is on the same high plane, and it requires much less expenditure to furnish luxurious equipment to be carried over , miles of road than it does to equip miles of the , so as to make it safe; and since the expenditure for safety appliances and permanent way is not seen and felt by the passenger so long as he is carried in safety, it is not, therefore, so prominent before the public gaze as is the handsome station and the palatial car. on one road in great britain, having but , miles of track, there are employed more men in the manufacture and installation of signal work than are employed by all the signal companies and in the signal departments of all the railroads of the united states, where we are now operating about , miles. * * * * * miscellaneous notes. orders for large quantities of aluminum have been received within the last few weeks by the pittsburg reduction company from the principal foreign nations for the equipment of their armies. the contracts aggregate about fifty tons a month, russia being the largest consumer. according to the return published by the minister of agriculture, the consumption of horseflesh in paris has decreased slightly in the last year, being only , tons, as against , tons for - . this was the meat derived from , horses, mules and donkeys slaughtered during the twelve months; but a very strict supervision is exercised, and of these animals were condemned as unfit for human food. the flesh of the remainder was sold at stalls or shops, and, although the fillet and undercut made as much as d. a pound, the inferior parts sold for d. or less, and most of the meat was used for making sausages. according to la propriété industrielle, , austrian patents were granted in ( , in ). of these, residents of the austro-hungarian monarchy received , ( , in ), austrians coming first with , ( , in ), hungarians second with ( in ), while residents of bosnia and herzegovina secured patents ( in ). among foreigners the following show an increase over : united states, ( ); great britain, ( ); france, ( ); switzerland, ( ); belgium, ( ); sweden and norway, ( ); italy, ( ); russia, ( ); australia, ( ); and netherlands, ( ). a decrease is shown by germany, , ( , ); denmark, ( ); canada, ( ); and spain, ( ). the total number of austrian patents granted to foreigners in was , , as against , in . english and french lighthouses.--an english engineer named purves has just made a comparison in regard to the intensity of light of the lighthouses on the english coasts and those which illuminate the shores of france. the comparison shows results which are altogether favorable to france. the average illumination intensity of eighty-six english lighthouses of the first class is , candle power, while thirty-six first class french lighthouses give an average of , candle power. the difference is more striking if the lighthouses constructed within the last ten years be considered. since france has built eleven lighthouses, whose average intensity of light is , , candle power; the new lighthouse of eckmühl gives , , . according to mr. purves, the superior intensity of light of the french lighthouse lies in the use of the flashing rays, which have not yet found favor in england. in an address by thomas morris, before the staffordshire, england, iron and steel works managers on the remarkable achievements that have been reached in the manufacture of fine wire, the interesting fact was mentioned that the lecturer had been presented by warrington, the wire manufacturer, with specimens for which some $ . per pound were paid, or more than $ , per ton--drawn wire, largely used in the construction of piano and other musical and mechanical instruments. among these specimens also was pinion wire, at a market price of $ . per pound, or $ , per ton. it took hairsprings to weigh an ounce of ½ grains; , , of these were required to make a ton, and, taking one to be worth ½ cents, the value of a ton of these cheap little things ran up to over $ , . the barbed instruments used by dentists for extracting nerves from teeth were even more expensive, representing some $ , , per ton. at a fête in the elysée palace the other day one of the features prepared for the entertainment of the guests was a cinematograph, which contained views taken during president faure's visit to st. petersburg. one of the pictures settled for the president a question which had been troubling him considerably. several months ago a german paper printed an interview with bismarck, in which the ex-chancellor commented on m. faure's visit to st. petersburg, saying that the frenchman had conducted himself according to etiquette except on one occasion, when, on his arrival in the russian capital he had been saluted by the cossack guard of honor, he had returned the salute with the hand, not with the hat. m. faure being a civilian, this was a serious breach of etiquette, bismarck said. the interview was reprinted in the french papers and caught the president's eye. he was much concerned about the matter and asked several friends who had been present if he had actually committed the breach. no one could remember. then came the cinematograph show. as the small audience gazed upon the screen they saw the president's image advance with slow, dignified step before the cossacks, then all at once raise his hand to his hat, which he lifted with the quick motion so familiar to parisians. the guests burst into applause and the president smiled. bismarck was mistaken. "we hear a great deal regarding the decline of our shipping interests, and so far as our shipping in the foreign trade is concerned it is unfortunately true," says the boston commercial bulletin. "but few people realize the immensity of our coastwise commerce. the custom house figures on the shipping of the port of new york for show that there were , arrivals of vessels from foreign ports, , from eastern domestic ports, and , from southern domestic ports. of the foreign, , were british, of which , were steamships; were american, of which were steamships, and were german of which were steamships. this statement shows that the arrivals from american ports were nearly three times those from foreign countries, though of course this proportion is not borne out in tonnage, vessels on the deep sea trade averaging larger. but it will be doubtless a surprise that of the shipping from foreign ports more than one-fifth were american. at other atlantic and gulf ports this proportion undoubtedly does not hold true, but these figures show a less doleful condition of the american marine than some people have been led to expect. when it is remembered that the coastwise fleet numbers many steamers of , to , tons and many sailing craft of , tons and upward, it will be seen that we are yet a sea power of the first class, in fact exceeded only by england." * * * * * selected formulÆ. essence of pepsin.-- . pepsin (pure) grains. dilute muriatic acid drops. simple elixir fl. ounces. glycerin " water " angelica wine " dissolve by agitation and filter through purified talcum. . glycerole of pepsin parts. sherry wine " glycerin " simple elixir, to make " . pepsin in scales grains. glycerin fl. ounce. elixir taraxacum compound " alcohol " oil of cloves drop. sirup fl. ounces. dilute hydrochloric acid fl. drachm. water, to make fl. ounces. --pharmaceutical era. applications to insect bites.--brocq and jacquet (indépendance médicale, october ) recommend the following for the bites of bugs, fleas and gnats: . camphorated oil of chamomile parts. liquid storax " essence of peppermint " m. . olive oil parts. storax ointment " balsam of peru " m. . naphthol to parts. ether, enough to dissolve it. menthol ¼ to part. vaseline parts. bead for liquors.--in the liquor trade, anything added to liquors to cause them to carry a "bead" and to hang in pearly drops about the side of the glass or bottle when poured out or shaken is called "beading," the popular notion being that liquor is strong in alcohol in proportion as it "beads." the object of adding a so-called "bead oil" is to impart this quality to a low-proof liquor, so that it may appear to the eye to be of the proper strength. the following formulas for "bead oil" are given: . sweet almond oil fl. ounce. sulphuric acid, concentrated " sugar, lump, crushed ounce. alcohol, sufficient. triturate the oil and acid very carefully together in a glass, wedgwood or porcelain mortar or other suitable vessel; add by degrees the sugar, continue trituration until the mixture becomes pasty, and then gradually add enough alcohol to render the whole perfectly fluid. transfer to a quart bottle and wash out the mortar twice or oftener with strong alcohol until about fluid ounces in all of the latter has been used, the washings to be added to the mixture in the bottle. cautiously agitate the bottle, loosely corked, until admixture appears complete, and set aside in a cool place. this quantity of "oil" is supposed to be sufficient for gallons of liquor, but is more commonly used for about or gallons. the liquor treated with this "oil" is usually allowed to become clearer by simple repose. . soapwort, coarsely ground ounces. diluted alcohol, enough to make gallon. extract the soapwort by maceration or percolation. this is also intended for gallons of liquor, preferably adding to the latter one-half gallon of simple sirup. the ingredients of the above formulas, according to the "manual of beverages," are not injurious--not at least in the quantities required for "beading." it is said that beyond a certain degree of dilution of the liquor with water, these preparations fail to produce the intended effect. the addition of sugar or sirup increases their efficacy. --pharmaceutical era. quinine hair tonic.-- . quinine sulphate part. tincture cantharides " glycerin " alcohol " tincture rhatany " spirit lavender " . tincture cinchona " tincture cantharides " peru balsam " tincture soap " cologne water " cognac , " oil bergamot " oil sweet orange " oil rose geranium " . bisulphate of quinine ½ ounce. vinegar of cantharides ½ " spirit of rosemary " lavender water " glycerite of borax " glycerin " distilled water " caramel, sufficient to color. --pharmaceutical era. soap for removing rust.-- parts by weight. whiting oil soap cyanide of potassium water dissolve the soap in water over the fire and add the cyanide, then little by little the whiting. if the compound is too thick, which may be due either to the whiting or the soap employed, add a little water until a paste is made which can be run into an iron or wooden mould. this will remove rust from steel and give it a good polish.--oils, colors and drysalteries. * * * * * the newfoundland and nova scotia passenger steamer "bruce." messrs a. & j. inglis, shipbuilders and engineers, of pointhouse, glasgow, have recently built a somewhat unique and certainly interesting steamer, for the conveyance of passengers between port an basque, in newfoundland, and sydney, cape breton, in connection with the newfoundland and canadian systems of railways. the distance from port to port is about one hundred miles, and the vessel has been designed to make the run in six hours. messrs. reid, of newfoundland, who have founded the line of steamers to perform this service, intrusted to messrs. inglis the task of producing a vessel in all respects suitable for the work to be accomplished. the steamer "bruce," the pioneer steamer, an illustration of which we are enabled to produce, is the result. the navigation of the waters in which this vessel will be employed is attended with some difficulties. not only are storms of frequent occurrence, but in the months of winter and spring large quantities of drift ice are commonly encountered. to obtain the necessary speed and carry all that was required on a suitable draught of water, it was essential that the "bruce" should be built of steel, but in view of the severe structural and local stresses to which she must inevitably be subjected when at sea, it was necessary to afford adequate stiffening and means for preventing penetration or abrasion by ice. hence the frames are more closely spaced than is usual in vessels of her size, numerous web frames associated with arched supports at the main deck and adjacent to the waterline are fitted throughout her entire length, and a belt of -inch greenheart planking, with a steel sheathing over it at the fore part of the vessel, is further provided. indeed, throughout the vessel, every precaution has been taken with a view to insure her efficiency and safety when running swiftly from port to port, while at the same time the materials employed have been most wisely, judiciously and economically distributed. [illustration: the newfoundland and nova scotia passenger steamer "bruce."] the dimensions of the "bruce" are feet long, feet inches broad, and feet deep, her gross tonnage being tons. she has been built with very fine lines, a considerable rise of floor, and with a graceful outline, which gives her the appearance of a large yacht. our illustration shows the "bruce" when running at a speed of upward of knots on the measured mile at wemyss bay. not only has the structure of the vessel been skillfully designed, but her internal fittings are admirably arranged. it is really most interesting to note with what ingenuity passenger accommodation of a somewhat extensive character has been provided in so small a vessel. the "bruce" has berths for seventy first-class and one hundred second class passengers, and the accommodation is of a very luxurious kind. the berths are between the awning and main decks, where there is also a special apartment set apart for ladies, and at the fore end for the officers' quarters. besides these a large and handsome dining saloon is situated on the main deck, richly upholstered and fitted with unique little window recesses, which besides adding to the appearance of the apartment, furnishes additional dining accommodation. it is done up in dark mahogany panels, fringed with gold. the chairs are upholstered in blue morocco, and the floor is laid with a turkey carpet. all the other rooms are in dark polished oak. a large smoking room is also provided on the main deck. the "bruce" is further fitted with a complete installation of electric lighting, together with an electric search light; has lord kelvin's deep sea sounding apparatus and compasses, also caldwell's steam steering gear and winches, weir's evaporators and pumps. alley and mclellan's feed water filters, and howden's forced draught. she is steam heated throughout, and in every detail of the sanitary arrangements the health and comfort of the passengers have been attended to. six lifeboats, having accommodation for people, are hung in davits. when fully laden she carries tons of cargo in her holds and tons of coal in her bunkers. the contract speed for the "bruce" was knots--and to obtain this messrs. inglis fitted her with triple-expansion engines, which we shall illustrate in another impression, having cylinders inches, inches and inches in diameter, with a inch stroke. steam is supplied from four boilers loaded to a pressure of pounds per square inch. when on the measured mile a mean speed of about ¼ knots was obtained with an indicated horse power of , the engines running at revolutions per minute. the vessel has arrived safely at newfoundland, having performed the voyage at a mean speed of very little under knots, a most satisfactory performance. she has been running some little time on her route and been giving most satisfactory results.--we are indebted to london engineer for the cut and description. * * * * * heat in great tunnels. one phase of the construction of tunnels through the alps was recently discussed by m. brandicourt, secretary of the linnæan society of the north of france, in the columns of la nature. he showed that only a few thousand feet below the eternal snows of that region so high a temperature may be found that workmen can scarcely live in it. nearly all of the other difficulties encountered in those enterprises had been foreseen. this one was a great surprise. it shows how the interior heat of the earth extends above sea level into all great mountainous uplifts on the earth's surface. during the tunneling of mont cenis, says m. brandicourt, the temperature of the rock was found to be . degrees c. ( . degrees f.) at about , meters ( , feet) from the entrance. it reached . degrees ( degrees f.) in the last meters ( , feet) of the central part. the workmen were then about , meters ( , feet) below the alpine summit, whose mean temperature is degrees below zero ( degrees f.) thus there was a difference of . degrees: that is, one "geothermic" degree corresponded to about meters. this elevation of temperature was not at first regarded with anxiety. soon a draught would be produced and would ameliorate the situation. it was time, for the disease known as "miner's anæmia" had begun to claim its victims. the situation at st. gothard was much more serious. as at mont cenis, a temperature of degrees c. ( degrees f.) was found about , meters from the portals of the tunnel. but there remained yet , meters of rock to pierce. in the center of the tunnel there was observed for several days a temperature of degrees ( degrees f.) generally it did not vary much from . degrees ( . degrees f.), a sufficiently high degree, if we remember that the men's perspiration was transformed into water vapor, and that the air was nearly saturated with humidity. in these conditions work was very difficult, and the horses employed to remove the debris almost all succumbed. man can bear more than animals. in an absolutely dry air he can endure a temperature of degrees ( degrees f.) but in an atmosphere saturated with water, underground, where the breath of the workmen fills the narrow space with poisonous vapors, a temperature of even degrees ( degrees f.) entails serious consequences. in a large number of workmen the bodily heat rose to degrees ( degrees f.) and the pulse to and even a minute. the most robust were obliged to lay off one day out of three, and even the working day was itself reduced to five hours, instead of seven or eight. according to dr. giaconni, who for ten years attended the workmen at mont cenis and st. gothard, the proportion of invalids was as large as to the . more strange yet, the report of the physicians who dwelt at the works notes the presence among the workmen of the intestinal parasites called "ankylostomes," which have been observed in egypt and other tropical countries, and which are the cause of what scientists call "egyptian chlorosis" or "intertropical hyperæmia." this pathologic state is observed only in the hottest regions of the earth. the victim becomes thin, pale and dark. he is bathed in continual sweat, devoured by inextinguishable thirst, and the prey of continual fever. and thus, adds mr. lentherie, "the most robust mountaineer had only to pass a few months in the depths of the alps to contract the germs of a tropical disease. under the thick layer of snow and ice that enveloped him he had to work naked like a tropical negro or an indian stoker on a red sea steamer; and in this alpine world, where everything outside reminds one of the polar climate, he sweltered as in a caldron and often died of heat." the bad conditions found at st. gothard will be met also, very probably, in the new alpine tunnels that have been projected in recent years--those at the simplon, st. bernard and mont blanc. it can be predicted that for mont blanc in particular the temperature of degrees ( degrees f.) will be far exceeded. m. de lapparent even considers that the figure of degrees ( degrees f.) proposed by some geologists is moderate, and errs by defect rather than by excess. the engineer stockalpa, who for four years has directed one of the workshops at st. gothard, and has made a profound study of this temperature question, does not hesitate to say that under mont blanc the temperature will be degrees ( degrees f.) at three kilometers from the entrance, that it will reach degrees ( degrees f.) under the saussure pass, and . degrees ( degrees f.) under the tacul peak, falling again to degrees ( degrees f.) under the white valley. these are only probabilities, but they are founded on facts, and we may imagine all the preventive measures that they will render imperative. the experience that has been acquired in these latter years has indicated the best methods of ventilation and cooling. the compressed air used in the workings produces by its escape a very sensible lowering of the temperature, which can be made still lower by using saline solutions whose freezing point is as low as - degrees ( degrees f.), and which will circulate through pipes along the tunnel. the removal of the debris can be effected by electric locomotives; thus the horses, which use up the precious air, can be done away with. the electric light, which can be operated without contamination or consuming the air, will also render great service; these improvements can all be carried out with ease. together with the preceding, they will form a group of processes that will enable us to gain the victory over the interior heat of the great alpine tunnels. * * * * * an english steam fire engine. [illustration: an english steam fire engine.] the machine which we illustrate has lately been constructed by messrs. merryweather & sons, of greenwich road, with the view to combining the advantages of both horizontal and vertical steam fire engines. hitherto the horizontal engine has been considered by some firemen to be less handy of access than the vertical, and the vertical engine has had the undoubted disadvantage of not being stoked from the footplate. by shortening the length of stroke and constructing a special pump, the makers have been able to keep the engine sufficiently high in relation to the boiler to enable the firedoor to be placed directly in the rear of the boiler and underneath the engine, thus enabling the boiler to be stoked en route, and allowing access from the footplate to the starting valve, the suction and delivery connections, the whole of the boiler fittings and feed arrangements. this enables one man to drive and stoke the engine, and to attend to the suction and delivery hoses, and it does not interfere at all with the stability of engine in traveling or at work, as the center of gravity is well below the top of the side frames. another feature is the absence of a main steam pipe, a bracket being arranged on the cylinders containing the steam passages, to bolt directly onto the top of the boiler. the close proximity of the engine to the boiler renders it peculiarly suitable for cold climates, and times of frost, reducing the chances of the pump or feed arrangements being frozen up. the pump valves are arranged between the barrels, and are all accessible by the removal of one cover, which weighs but lb. the engine, we understand, may be stopped, the cover removed, a damaged valve replaced, the cover put on again, and the engine restarted in two minutes. a slotted link is used with a crankshaft for regulating the length of stroke. all the bearings have large wearing surfaces, and substantial eccentric straps are used, the whole of the motion being simple and accessible. there are three different methods of feeding the boiler, viz., by feed pump driven by the crosshead of the main pump, by forcing water directly into the boiler from the main pump, and by an injector taking its water from a tank either supplied from the main pump or by a bucket when pumping dirty water. all the feed pipes are fitted with strainers where attached to the main pump. drop feed lubricators are fitted on the cylinders, and an efficient system of lubrication is provided for the rest of the working parts. the carriage frame, hose box, etc., are of the same design as usually employed for engines of this class, with the exception of the fore carriage, which is fitted with a cross spring in the rear, as well as the two longitudinal springs. this arrangement makes the engine run more lightly, and removes much of the strain on the side frames when traveling rapidly on a rough road. the wheels are fairly light for the weight they have to carry, and have gun metal stock hoops with diamond pent rims to prevent the men slipping when mounting in a hurry. the engine and boiler work is brightly polished where-ever possible, and the whole machine has a handsome appearance.--engineering. * * * * * apparatus for obtaining the cubature of trees. in the exploitation of forests it is an important matter to be able to measure the cubature of trees, and the process most generally employed consists in determining their height and mean circumference, the apparatus used for this latter measurement being compasses having the form of the calipers used by mechanics. the figure indicated is read upon the graduated rule and is called off in a loud voice to another person, who at once writes it down. there are several causes of error: it is possible that the reading may be incorrectly made or improperly called off, or be misunderstood or incorrectly noted. finally, it is a somewhat fatiguing operation that is often dispensed with and the measurement made by estimate. in order to do away with all such causes of error, m. jobez, a mining engineer, has had m. peccaud construct an apparatus that automatically registers all the measurements upon a paper tape analogous to that used in the morse telegraphic apparatus. [illustration: fig. .--apparatus for obtaining the cubature of trees.] the registering mechanism (fig. ) is fixed to the movable branch that forms the slide of the instrument. it is so arranged that when this branch is slid along the rule carrying the graduations, a gearing causes the revolution of a wheel, d, which carries figures corresponding to such graduation. at the same time, two feed rollers, e, cause a small portion of the paper tape (which is wound upon a spool, a) to move forward and wind around a receiving spool, b. after the apparatus has been made accurately to embrace the trunk of the tree to be measured, it is removed and a pressure given to the lever, h, which applies the paper to the type wheel, d. a special button permits, in addition, of making a dot alongside of the numbers, if it be desired to attract attention to one of the measurements, either for distinguishing one kind of a tree from another or for any other reason. with this apparatus one man can make all the measurements and inscribe them without any possible error and without any fatigue. it is possible for him to inscribe a thousand numbers an hour, and the tapes are long enough to permit of , measurements being made without a change of paper. there is, therefore, a saving of time as well as perfect accuracy in the operation. in order to make the calculations necessary for the estimate, m. laurand has devised a sliding rule which facilitates the operation and which is based upon the method that consists in knowing the height and mean circumference of the tree. the circumference taken in the middle is divided by , . or according as one employs the quarter without deduction or the sixth or fifth deduced. this first result, multiplied by itself and by the height, gives the cubature of the tree. as for the value, that is the product of this latter number by the price per cubic meter. it will be seen that there is a series of somewhat lengthy operations to be performed, and it is in order to dispense with these that has been constructed the rule under consideration, which, like all calculating rules, consists of two parts, one of which slides upon the other (fig. ). upon each of these there are two graduated scales, or four in all, the first of which is designed for the circumference and the second for the height of the tree, the third for the price of the cubic meter and the fourth for the total result, that is, the value of the entire tree. the arrangements are such that, after the number corresponding to the circumference of the tree has been brought opposite that corresponding to its height, the result will be found opposite the price per cubic meter. [illustration: fig. .--laurand's calculating rule.] thus, in the position represented in the figure, we may suppose a tree having a circumference of . m. and a height of . m.; then, if a cubic meter is worth francs, the tree will be worth francs. in order to simplify the calculations and the construction of the rule, no account is taken of points; but this is of no importance, since the error that might be made in misplacing one would be so great that it would be immediately detected. a franc tree would not be confounded with a or a franc one. as an approximation, the first two figures of the result are obtained accurately; and that suffices, because, since the whole is based upon an approximate measurement, which is the mean circumference of the tree, we cannot exact absolute precision in the results. the essential thing is to have a practically acceptable figure.--la nature. * * * * * egypt's population, according to the census taken last june, is , , , more than double the population in . the foreign residents are , ; of these, , are greeks, , italians, , britishers, including the army of occupation, and , french subjects, including algerians and tunisians. twelve per cent. of the native males can read and write; the other egyptians are illiterate. cairo has , inhabitants, alexandria , , port said , , and suez , . * * * * * machine moulding without stripping plates.[ ] [footnote : paper presented at the new york meeting (december, ) of the american society of mechanical engineers, and forming part of volume xix. of the transactions.] by e. h. mumford, plainfleld, n. j. (member of the society.) moulding machines may be classed under three heads. first, machines which only ram the moulds, and, when the ramming is done by means of a side lever, by hand, are generally called "squeezers." second, machines which only draw the patterns, the ramming being accomplished by the usual hand methods. third, machines which both ram the moulds and draw the patterns, ramming either by a hand-pulled lever or by fluid pressure on piston or plunger and drawing the patterns through a plate called a "stripping plate" or "drop plate"--till recently the usual method--or without the use of this plate fitting everywhere to pattern outline at the parting surface, the patterns being effectively machine guided in either case. it is to the third class that the machine which is used to illustrate the subject of this paper belongs, and which would seem to have enough that is novel in the application of machinery to the foundry to merit the attention of the society. [illustration: fig. .--ordinary method of drawing pattern spike and rapper.] at the risk of appearing pedantic, but with a view to developing an appreciation of the true function of the method of pattern drawing used in this machine, attention is called to the following sectional views of moulds and ways of drawing patterns occurring in machine moulding. fig. shows an ordinary "gate" of fitting patterns being drawn from the drag or nowel part of the mould by means of a spike and rapper wielded by the moulder's hand after cope and drag have been rammed together on a "squeezer" and cope has been removed. frequently the pernicious "swab" is used to soak and so strengthen joint outlines of the sand before drawing patterns, in such cases as this. in this case, before cope is lifted, these patterns must be vigorously rapped through the cope; an amount depending (and so does the size of the casting) upon the mood and strength of the moulder. fig. shows the stripping or drop plate method of drawing patterns. [illustration: fig. .--stripping plate method of drawing patterns.] in this method the patterns are not rapped at all and are drawn in a practically straight line so that the mould is absolutely pattern size. the stripping plate is fitted accurately to every outline at the joint surface of the patterns, obviously at considerable expense, and, of course, at the instant of drawing the patterns, supports the joint surface of the mould entirely. this is, at first sight, an ideal method of drawing patterns, and it has for years been the only method practiced on machines. it has two disadvantages. the patterns are separated from the stripping plate by the necessary joint fissure between the two. fine sand continually falls into this and, adhering to the joint surfaces more or less, grinds the fissure wider. this leads to a gradual reduction of size of patterns on vertical surfaces and a widening of the joint fissure often to such an extent that wire edges are formed on the mould, causing, on fine work, "crushing" and consequently dirty joints. a nicely fitted but worn plate of twenty-four pieces which had cost, at shop expense only, $ , was recently replaced by a plate of twenty-eight pieces, fitted ready for the machine under the new system about to be described, for not more than $ . the stripping plate method has another drawback, not always appreciated, probably because accepted as inevitable. stripping plate patterns are not rapped, and there frequently occur on surface of patterns, remote from the action of the stripping plate, rectangular corners just as important to mould sharply as those at the parting line. such corners have either to be filleted or "stooled" in stripping plate work, and neither method often is practicable. when the entire pattern and plate are vibrated so that the corners where the pattern joins the plate draw perfectly, as they do in the machine to be described, it is obvious that similar corners anywhere on pattern surface will draw equally well. the vibrating of patterns, or rather of moulds, during the operation of drawing the patterns possesses little of novelty. ever since a bench moulder's neighbor first rapped the bench while he lifted a cope or drew a pattern, the thing has been done in one way or another. in fact, machines are now and then found on the market in which a device like a ratchet or other mechanical means for jarring the machine structure during pattern drawing renders the working of easy patterns without stripping plates possible. the idea of applying a power driven vibrator directly to the plate carrying the patterns to thus vibrate them independently of other parts of the machine and the flask and sand has been the subject of the issue of patents to mr. harris tabor, and the various figures shown will serve to illustrate the mechanism. briefly, the operation of the machine is as follows: the ramming head shown thrown back at the top of the machine is drawn into a vertical position after flask has been placed and filled with sand. the -way cock shown at the extreme left is then quickly opened, admitting compressed air of to pounds pressure to the inverted cylinder shown at the center of the cut. the cylinder, with the entire upper portion of the machine, is thus driven forcibly up against the ramming head, flask, sand and all. often a single blow suffices to rain the mould--often the blow is quickly repeated, according to the demands of the particular mould in hand. gravity returns the machine to its original position, as the -way cock opens to exhaust. after pushing the ramming head back and cutting sprue, if the half mould is cope, the operator seizes the lever shown just inside the -way cock at the right, and, drawing it forward and down, raises the outer frame of the top of machine containing the flask pins, with flask and sand thereon, away from the patterns, thus drawing them from the sand. just as he seizes the pattern drawing lever with his right hand, he presses with his left on the head of a compression valve shown at the left side of top of machine, thus admitting air to the pneumatic vibrator already referred to. [illustration: fig. .--power driven vibrator machine.] fig. , a rear view of the machine, shows at the top center, with its inlet hose hanging to it, this vibrator, which is shown in section in fig. . it consists simply of a double acting elongated piston having a stroke of about / inch in a valveless cylinder and impacting upon hardened anvils at either end at the estimated rate of , blows per minute. [illustration: fig. .--section through vibrator.] the method of communicating the rapid yet small oscillations of the vibrator to the patterns and yet keeping them from being transmitted to the rest of the mechanism is this: a frame, called a vibrator frame, to which the pneumatic vibrator is bolted and keyed, is shown in fig. . to this frame the plate carrying the patterns, often, in cases of patterns having irregular parting lines, forming one and the same casting with the patterns, is fastened by the four machine screws, the small tapped holes for which are shown in the corners. in fact, in changing patterns, the process consists of simply removing these four machine screws, taking up the pattern plate and screwing to the vibrator frame the new pattern plate. the vibrator frame itself is secured to the machine structure by the four larger bolts, the holes for which are shown in the inner corners. these bolts are, as shown in fig. , surrounded by thick bushings. these bushings are elastic to such a degree as to absorb the sharp vibrations of vibrator frame and patterns, while so firm and well fitted as to hold patterns accurately to their position. [illustration: fig. .--vibrator frame.] the action of the vibrator is such as to give to the entire pattern surface an exceedingly violent shiver, making it impossible that any sand should adhere to this surface, while the magnitude of the actual movement of the pattern is so slight that it is found to fill the mould so completely that it is impracticable to draw it a second time without rapping. yet, so truly are the patterns held and so little disturbed from their original position, that it is perfectly practicable to return patterns to a mould having the finest ornamental surface in the ordinary practice of "printing back." in cases where deep pockets of hanging sand occur, which cannot be held during lifting off and rolling over, machines are arranged to roll the flask over in their operation and draw the patterns up under the influence of the pneumatic vibrator, though, owing to the time consumed in the rolling over process (and each operation counts in seconds on a moulding machine) this style of machine is not usually as rapid in its working as the simpler type, in which the flasks come off in the same way they go on. [illustration: fig. . set of patterns fitted to plates.] fig. shows a set of patterns as they are ordinarily fitted to plates for this machine. round holes will be noticed at places in the plate surface. these are openings for the insertion of what are called "stools." when it is found necessary to support the sand surface at any point, or generally, round holes are drilled through either plate or pattern surface and loose cylindrical pieces are dropped into these holes, their upper end surfaces being flush with the plate or pattern surface and their lower ends resting on the plate called, from this use, a stool plate. this plate appears in fig. at a and is hung solidly by the brackets shown at b from the frame which carries the flasks, so that it has the same upward motion as the flasks, and the upper ends of the stools remain in contact with the sand of the mould until same is lifted from machine. fig. , showing a vertical section through a machine, will make perfectly clear the position and action of these stools. [illustration: fig. . vertical sections fitted to plates.] as illustrating the importance of being able to work without stripping plates on a line of work which is much more extended than that possible with them, we may say that a machinist with a drill press supplied with split patterns and planed pattern plates has matched and fixed five sets of from four to eight pieces in a day: and wooden patterns fitted for temporary use in the same way are of frequent occurrence when it is not thought wise to go to the expense of metal patterns on account of the relatively small number of castings to be made from them. it is not perhaps too much to say that pattern expense is not the final evil of the costly and not durable stripping plate patterns. * * * * * artificial india rubber. one of the most recent important events in the history of chemistry was the discovery by an english professor that a substance corresponding in every respect to india rubber may be produced from oil of turpentine. dr. w. a. tilden, professor of chemistry in mason college, birmingham, began a series of experiments with a liquid hydrocarbon substance, known to chemists as isoprene, which was primarily discovered and named by greville williams, a well known english chemist, some years ago as a product of the destructive distillation of india rubber. in , says the new york sun, dr. tilden discovered that an identical substance was among the more volatile compounds obtained by the action of moderate heat upon oil of turpentine and other vegetable oils, such as rape seed oil, linseed oil and castor oil. isoprene is a very volatile liquid, boiling at a temperature of about degrees fahrenheit. chemical analysis shows it to be composed of carbon and hydrogen in the proportions of five to eight. in the course of his experiments dr. tilden found that when isoprene is brought into contact with strong acids, such as aqueous hydrochloric acid, for example, it is converted into a tough elastic solid, which is, to all appearances, true india rubber. specimens of isoprene were made from several vegetable oils in the course of dr. tilden's work on those compounds. he preserved several of them and stowed the bottles containing them away upon an unused shelf in his laboratory. after some months had elapsed he was surprised at finding the contents of the bottles containing the substance derived from the turpentine entirely changed in appearance. in place of a limpid, colorless liquid the bottles contained a dense sirup, in which were floating several large masses of a solid of a yellowish color. upon examination this turned out to be india rubber. this is the first instance on record of the spontaneous change of isoprene into india rubber. according to the doctor's hypothesis, this spontaneous change can only be accounted for by supposing that a small quantity of acetic or formic acid had been produced by the oxidizing action of the air, and that the presence of this compound had been the means of transforming the rest. upon inserting the ordinary chemical test paper, the liquid was found to be slightly acid. it yielded a small portion of unchanged isoprene. the artificial india rubber found floating in the liquid upon analysis showed all the constituents of natural rubber. like the latter, it consisted of two substances, one of which was more soluble in benzine or in carbon bisulphide than the other. a solution of the artificial rubber in benzine left on evaporation a residue which agreed in all characteristics with the residuum of the best para rubber similarly dissolved and evaporated. the artificial rubber was found to unite with natural rubber in the same way as two pieces of ordinary pure rubber, forming a tough, elastic compound. although the discovery is very interesting from a chemical point of view, it has not as yet any commercial importance. it is from such beginnings as these, however, that cheap chemical substitutes for many natural products have been developed. few persons outside of those directly connected with rubber industries realize the vast quantities imported yearly into this country. last year there were brought into united states ports, as shown by the reports of the customs officers, no less than , , pounds of india rubber. the industry has been steadily progressive since the invention of machinery for manufacturing it into the various articles of everyday use. the wonderful growth of the india rubber interests in this country will be seen from the statistics compiled in the tenth census. in there were imported , , pounds at an average rate of $ per pound; in the imports were , , pounds, at an average price of cents per pound; in , , pounds were imported, at an average price of cents per pound. the present price of india rubber varies from cents per pound for fine para rubber to cents per pound for the cheapest grade. it will be seen that, notwithstanding the increase in importations, the price of the raw material remains at a comparatively high figure. many experiments have been made to find a substance possessing the same properties as india rubber, but which could be produced at a cheaper rate. many of the compositions which have been invented have been well adapted for use for certain purposes and have been used to adulterate the pure rubber, but no substance has been produced which could even approach india rubber in several of its important characteristics. there has never been a substance yet recommended as a substitute for rubber which possessed the extraordinary elasticity which makes it indispensable in the manufacture of so many articles of common use. great hopes were at one time placed in a product prepared from linseed oil. it was found that a material could be produced from it which would to a certain extent equal india rubber compositions in elasticity and toughness. it was argued that linseed oil varnish, when correctly prepared, should be clear, and dry in a few hours into a transparent, glossy mass of great tenacity. by changing the mode of preparing linseed oil varnish in so far as to boil the oil until it became a very thick fluid and spun threads, when it was taken from the boiler, a mass was obtained which in drying assumed a character resembling that of a thick, congealed solution of glue. resin was added to the mass while hot, in a quantity depending upon the product designed to be made, and requiring a greater or less degree of elasticity. many other recipes have been advocated at different times to make a product resembling caoutchouc out of linseed oil in combination with other substances, but all have failed to give satisfaction, save as adulterants to pure rubber. among the best compounds in use in rubber factories at present is one made by boiling linseed oil to the consistency of thick glue. unbleached shellac and a small quantity of lampblack is then stirred in. the mass is boiled and stirred until thoroughly mixed. it is then placed in flat vessels exposed to the air to congeal. while still warm the blocks formed in the flat vessels are passed between rollers to mix it as closely as possible. this compound was asserted by its inventor to be a perfect substitute for caoutchouc. it was also stated that it could be vulcanized. this was found to be an error, however. the compound, upon the addition of from to per cent. of pure rubber, may be vulcanized and used as a substitute for vulcanized rubber. compounds of coal tar, asphalt, etc., with caoutchouc have been frequently tested, but they can only be used for very inferior goods. the need for a substitute for gutta percha is even more acute than for artificial india rubber. a compound used in its stead for many purposes is known as french gutta percha. this possesses nearly all the properties of gutta percha. it may be frequently used for the same purposes and has the advantage of not cracking when exposed to the air. its inventors claimed that it was a perfect substitute for india rubber and gutta percha, fully as elastic and tough and not susceptible to injury from great pressure or high temperature. the composition of this ambitious substance is as follows: one part, by weight, of equal parts of wood tar oil and coal tar oil, or of the latter alone, is heated for several hours at a temperature of from to degrees fahrenheit, with two parts, by weight, of hemp oil, until the mass can be drawn into threads. then one-half part, by weight, of linseed oil, thickened by boiling, is added. to each parts of the compound one-twentieth to one-tenth part of ozokerite and the same quantity of spermaceti are added. the entire mixture is then again heated to degrees fahrenheit and one-fifteenth to one-twelfth part of sulphur is added. the substance thus obtained upon cooling is worked up in a similar manner to natural india rubber. it has not been successfully used, however, without the addition of a quantity of pure rubber to give it the requisite elasticity. a substitute for gutta percha is obtained by boiling the bark of the birch tree, especially the outer part, in water over an open fire. this produces a black fluid mass, which quickly becomes solid and compact upon exposure to air. each gutta percha and india rubber factory has a formula of its own for making up substances as nearly identical with the natural product as possible, which are used to adulterate the rubber and gutta percha used in the factory. no one has as yet, however, succeeded in discovering a perfect substitute for either rubber or gutta percha. the history of chemistry contains many instances where natural products have been supplanted by artificial compounds possessing the same properties and characteristics. one of the most notable of these is the substance known as alizarine, the coloring matter extracted from the madder root. this, like india rubber, is a hydrocarbon. prior to all calico printing was done with the coloring matter derived from the madder root, and its cultivation was a leading industry in the eastern and southern portions of europe. in alizarine was successfully produced from the refuse coal tar of gas works and the calico printing business was revolutionized. the essence of vanilla, made from the vanilla bean, and used as a flavoring extract, has been supplanted by the substance christened vanilla by chemists, which possesses the same characteristics and is made from sawdust. isoprene, from which dr. tilden produced india rubber, is comparatively a new product, as derived from oil of turpentine. it yet remains to be seen whether rubber can be synthetically produced certainly and cheaply. the result of further experiments will be awaited with interest, as the production of artificial rubber at moderate cost would be an event of enormous importance. * * * * * deep and frosted etching on glass. the best means of producing these effects is by printing from a steel plate or lithographic stone on thin transfer paper, which, in turn, is made to give up the design to the surface of the glass, the exposed portions of the latter being then etched with acid. in preparing the steel plate, a coating of varnish is prepared by mixing parts by weight of oil of turpentine, of syrian asphaltum, of beeswax, of stearin, and of venice turpentine in the warm. the design is then copied in outline by tracing from the original, the shading being reproduced in a less detailed manner, but with fewer and bolder strokes, in order to adapt the picture to the process. it is then pricked through the tracing paper on to the varnish coating of the plate, and, after clearing out the lines with graving needles, the plate is etched with a mixture of vol. of water and to vols. of nitric acid, either by application or immersion; in the latter event the back of the plate must be varnished over. when the metal is bitten by the acid to about - of an inch in depth, the operation is finished. to transfer the design to the glass it is printed from the steel plate on to thin silk paper, the ink used being compounded from parts of oil of turpentine, , of syrian asphalt, of beeswax, of paraffin, and of thick litho varnish. the printing is performed in the usual manner, and the transfer laid on the warmed surface of the glass sheet or ware to be decorated, rubbed over uniformly with a cloth to make the ink adhere to the glass, and then the paper is moistened and taken off again, leaving the imprinted design behind. it is well to have the ink fairly thick, and rely on warmth to impart the necessary fluidity; otherwise the design may come away with the paper in patches, and be imperfect. for etching in the design on the glass, the edges of the latter are coated with the protective varnish, and then hydrofluoric acid is brushed over the exposed portions, which are thereby corroded, leaving the parts covered by the ink standing in relief. according as a clear or frosted etching is desired, the etching liquid is modified, being, for the latter purpose, composed of parts of ammonium fluoride, of common salt, of fuming hydrofluoric acid and of ammonia. this is brushed over the glass two or three times, and then rinsed off with lukewarm water. for deep etching, hydrofluoric acid is diluted with ½ vols. of water and stored for twenty-four hours before use. the objects are immersed in the baths for thirty to fifty minutes, and kept quite still the while. if the etching is to be left clear, the acid is neutralized by boiling the glass in soda, but if to be frosted afterward it is coated with the first named etching liquid while still damp. finally, the ink is washed off with turpentine, the glass rubbed over with sawdust, washed in hot lye and rinsed with water. grained or lined designs can be very suitably printed from a litho stone, on paper faced with a mixture of , parts of water, of wheaten starch, , of glycerine and of a thick solution of gum arabic, the ink for printing being prepared by melting and mixing parts of pure tallow, of white beeswax, of liquid mastic, and of pale resin, with parts of lampblack, of minium, and of litho varnish. in transferring the design to the glass, the latter, if flat, may be passed between india rubber rollers or protected by layers of gutta percha when the pressure is applied. the impression produced by this lithographic process has to be strengthened to enable the thin coating of ink to resist the etching liquid, and this is done by dusting powdered resin over the printed surface of the glass, brushing off all that does not adhere, and causing the remainder to attach itself to the ink by means of warmth, and so form an impervious covering. the further treatment is the same as that already described. these methods are particularly suitable for reproducing landscapes, etc., on thinly flashed glass of various colors.--diamant. * * * * * slate and its applications. slate is, as we know, merely a variety of argillite. slate quarries are found in england, switzerland and italy, but it is in france especially that the industry has been most extensively developed by reason of the large deposits that underlie its surface, particularly in the province of anjou, where they extend from trelaze to avrille, a distance of six miles, and in the department of ardennes, at remogne, fumay, etc. normandy, brittany, dauphiny and marne likewise possess quarries, although they are not so productive. the exploitation is commonly done in open quarry. after the vegetable mould (which in this case is called "cover") has been removed, we meet with a solid slate which it is difficult to split into laminæ, and it is not until a depth of at least fifteen feet is reached that we find a material that is fit to be exploited. all the best beds of slate, in fact, improve in quality in proportion as they lie deeper under the surface, near to which they have little value. without entering into details as to the exploitation of this product, let us say that the blocks have to be divided in the quarry, since, in the open air, they rapidly lose the property of readily splitting into thin, even laminæ. [illustration: slate store-vats for breweries.] slate has but slight affinity for water, and, moreover, resists atmospheric influences, humidity and heat pretty well. this property renders it valuable for a large number of domestic purposes. there is no certain proof, it is true, that it was employed by the ancients, but it is, nevertheless, extremely probable that it was used in mass at an early period for stair heads, pillars for buildings and as a material for fencing. the exploitation of the material became especially active at the period when the idea occurred to some one to use slate for the rooting of houses. it was employed for this purpose along with tiles as far back as the eleventh century in the majority of schistose districts. it is well known, for example, that fumay (ardennes) at this period had a brotherhood of slate quarrymen. a method of getting out the material and cutting it regularly was found toward the end of the twelfth century, and it was not till then that it became of general application. moreover, with the advent of the gothic period slate became indispensable for castle roofs, which have a conical form. the best slate for roofing purposes is hard, heavy and of a bluish gray color. a good slate should readily split into even laminæ; it should not be absorbent of water either on its face or endwise, a property evinced by its not increasing perceptibly in weight after immersion in water; and it should be sound, compact and not apt to disintegrate in the air. for a long time past there have been used in schools slate tablets upon which the pupils write with a pencil made of soft gray schist. this application, which is capable of rendering services in a host of details of domestic economy, has given rise to artificial slates, which, made by a process of moulding a composition analogous to cardboard pulp, present the same advantages as ordinary slate, while being much lighter. along about an englishman of the name of magnus utilized the property that slate possesses of taking a fine polish in the invention of what are called enameled slates. these products are used especially in the manufacture of table tops, mantelpieces, altars, etc. they very closely imitate the most expensive marbles, and their properties, along with their low price, have been the cause of their introduction into the houses of all classes of the english population, as well as into those of entire europe and america. the ease with which slate is obtained in slabs of large dimensions has greatly contributed in recent times toward still further increasing its applications. one of the first of such applications was the substitution of it in urinals for cast iron plates, which very rapidly oxidize and become impregnated with nauseous odors that necessitate a frequent cleaning and constitute a permanent source of infection. for a few years past, too, slate has been used, in the manufacture of vats designed for breweries. these vats, of which we show in the accompanying figure a model of the installation employed in the ivry brewery, are each ½ feet square and feet in depth. for leading the beer, which, upon coming from the brewing apparatus, must rest for a few days, they are connected by a system of pipes. a second system of pipes, which in our figure is seen running along the cellar vault, serves as a cooling apparatus and maintains a temperature of ° c. above zero in the vats arranged in two rows to the right and left. the details or even a simple enumeration of the new applications of slate would, in order to be anywhere nearly complete, necessitate a lengthy article. let us say in conclusion that slate is substituted for wood, which is too easily attackable, and for marble, which is much more costly, in our laboratories and amphitheaters and everywhere where the manipulation and stay of easily corrupted liquids and solids require the greatest cleanliness in the material of construction.--la science en famille. * * * * * birthplace of the oilcloth industry. in kennebec county, me., is the quiet borough of east winthrop, for more than half a century known wherever oilcloth carpeting was used as baileyville. were it not for the inventive brain of one of east winthrop's early inhabitants, says a contemporary, the village would hardly be known across the lake, but early in the present century one of the numerous family of maine baileys evolved a scheme to fill his purse faster than the slow process of nature was likely to do it in growing crops. oilcloth carpetings were not known in the long ago, when ezekiel bailey pictured in his mind how they might be made, and it was in the little hamlet of east winthrop that the conceit of their manufacture was hatched and executed. ezekiel bailey was, in the days prior to the war of , looked upon as a very likely boy. he was studious and industrious, and while other boys of the village were out in the white oak groves setting box traps for gray squirrels, and spearing pickerel by torch light in the waters of cobosseecontee, ezekiel was busy in his little workshop fashioning useful things to be used about the house. just how and when and where he was prompted to attempt the making of oilcloth carpet nobody now living at east winthrop seems to know. many of the burghers thought he was "a-wastin' uv his time," but they thought different some years later when great factories for the manufacture of oilcloth floor carpeting were erected in east winthrop, hallowell, new jersey, and other places. and ezekiel? he amassed a considerable fortune and left the path of life much easier for his kin to pursue. having met a peddler one day, he bought a table cover made of a combination of burlap and paint. such things were a luxury in the country at that time, and ezekiel bailey was shrewd enough to foresee a big demand for them if the cost could be moderated a bit. while thinking, an idea came to him, and following the idea a small voice which whispered: "make 'em yourself." he decided to try, and there is a legend to the effect that half the farmers of the village quit work to see the first table cover. procuring a square of burlap, or rather enough burlap from which to fashion a square of the desired size, ezekiel bailey framed up the fabric as the good old grandmas used to hitch up quilts at a quilting bee, the only difference being that the burlap was framed or stretched over a table made of planed boards large enough for the full spread of the burlap. with paint and brush he began his work. the first coat was a tiller; the next, a thicker one, gave body to the cloth, and when this was rubbed down to a smooth surface the last coat was prepared. this was of a different color and was spread on thick. then, with a straight edge, a piece of board with a true, thin edge, reaching across the whole surface of painted cloth, the finishing touches were put on. commencing at one end of the fabric, the straight edge was moved back and forth, and straight along over the fresh paint once or twice, and the whole thing left to dry. the first table covers were great curiosities, and the homes of the baileys were visited by all the neighboring housewives, who were anxious to see "how they worked." of course, it was easy to keep them clean, and they saved the woodwork of the table, which was recommendation enough. to see a cloth was to covet it, and it was not long before ezekiel bailey had a considerable business. employing a boy to help him, he turned out table cloths as fast as his limited facilities would permit, and, as he progressed, new ideas for decorating took shape in his mind. in less than a year he had men out on the road selling them. the turning out to perfection of an oilcloth carpet in those days was a task that would make a person in these piping times of labor-saving machinery wish for something easier. all the smoothing or rubbing down was done by hand. heavy, long-bladed knives, as big as the "sword of bunker hill," were used to scrape down the rough body coats of paint, and a smooth surface, on which to stamp the geometrical figures in colors, was fetched after long and laborious polishing with bricks and pumice stone. drummers employed by mr. bailey traveled to massachusetts, to new york, and away down into the south, and ere long the demand for oilcloth carpeting became so general that other factories were built and made to chatter and clank with the new industry. there was living not far from east winthrop at this time a shrewd, wideawake yankee farmer named sampson, who had kept his weather eye peeled on the progress of ezekiel bailey, and when housewives everywhere began to yearn for the new carpeting, taking a neighbor in as a partner, mr. sampson built a factory, and in a very short time was in a position to be considered a formidable rival of mr. bailey. but the originator of the oilcloth carpet was not to be outdone. discerning good returns from a plant established close to a big center of consumption, mr. bailey entered into a deal with new jersey capitalists, and a big factory was set a-going in that state. a trusted employe of the bailey concern, levi richardson (who still lives and is the proprietor of a modest little store in east winthrop), was sent to new jersey to instruct the green hands there in the art of manufacture. while thus engaged, mr. richardson's brain was busy with the problem of labor saving, and one day a phantom device for smoothing and rubbing down the first rough coats on the burlaps took form in his mind, and for some weeks he spent his spare time in experimenting. the result was the present patent used in most factories, whereby as much rubbing down can be done in one day as could have been accomplished in four by the old hand method. --industrial world. * * * * * the koppel electric locomotives. the question of the design of small locomotives for use on pioneer lines has been always a difficult matter. the needs of the railway contractor have called for such locomotives, for which several systems of power have been tried. in many ways the electric locomotive has distinct advantages over its rivals, steam and compressed air, for these narrow gage lines. reviewing these advantages briefly, we see that the electrical equipment is more economical to work, as one good stationary engine develops power much more cheaply than several small locomotives. again, the electric locomotive can be more readily designed for narrow gages than steam or compressed air locomotives. [illustration: fig. --an electric line equipped on the koppel system.] [illustration: fig. .--the section with the support for the overhead line.] a new system of equipment of such lines is now being introduced into this country by mr. arthur koppel, of leadenhall street, e. c. the keynote of this system is flexibility, the arrangements being such that extensions or alterations can be readily effected. in fact, the line is portable, and it is claimed also to be cheaper than the ordinary construction. the overhead conductor is employed, as can be seen from fig. , which gives a general view of a locomotive and train of skips on a line actually at work abroad. the supports for the wire are not provided by separate posts and brackets in the usual way, but by arched carriers attached to the sections of railway line, thereby forming a portable section of the electric railway, as illustrated by fig. . the steel carrier or "arch" is fixed to one of the sleepers, which is made of sufficient length for that purpose. on the straight line these line supports are placed about yards apart. in curves of a small radius each section of tramway is provided with an arch, to keep the line of the wire as nearly as possible parallel to the curve of the line. apart from these special extended sleepers with wire carriers attached, the line is constructed in the ordinary mariner with rails lb. per yard and upward. as the electric locomotives are lighter than steam locomotives, the weight of rail required is somewhat less. the special trolley for erecting the wires along the railway line is shown in fig. . this consists of an ordinary four wheeled platform wagon with ladder, and wire drum with tightening gear and clamps or grips for anchoring the trolley to the line. the wire is led over a sheave on top of the ladder and fixed to the picket post at the beginning of the line. when erecting the wire the trolley is pushed beyond the first carrier arch, clamped on to the rails, and the wire is then tightened by means of the tightening gear. it is then firmly fixed to the insulator on the carrier arch the tension in the copper wire is taken up by a second portable ladder, which is also provided with a tightening gear and can be clamped to the rails in the same manner as the trolley, so that the trolley can then be pushed behind the second carrier arch and the process previously described repeated. by the tension in the wire the carrier arches acquire the necessary stability, while without the procedure previously described it would be impossible to use such light arches attached to the sleepers. on permanent lines, the extreme ends of the wire are attached to properly anchored picket posts. on portable lines, on the other hand, the trolley with the wire drum is fixed to the rails at the end of the line, as shown in fig. , so as to enable the line to be lengthened or shortened, as may be required, with ease. [illustration: fig. .--the straining gear and terminal anchor.] care is taken in insulating the drum and ladders so as to prevent leakage from this erecting trolley to earth. the feeders from the power house to the overhead wire and to the rails respectively are erected on light iron posts, which have also been standardized by mr. koppel. a specimen of these posts with an anchored stay is shown in fig. . all these details are arranged for convenience of the contractor required to rapidly equip a line of railway, which can also be removed as soon as the work has been done. [illustration: fig. .--light pole for carrying the feeders.] [illustration: fig. .--the koppel locomotive.] the locomotive used is varied in form with the gage of the line, but we are particularly concerned with those for gages under inches. one form of such locomotive without a hood to protect the driver is shown in fig. . in this locomotive the gear is the same as that of the next illustration, but it is securely boxed in a watertight iron cover. the controlling gear is then placed vertically in front. figs. and show the details of the electrical and mechanical parts of this locomotive when fitted with a platform at either end, and with a hood. the motor. m, is of the internal pole type, and is supported on the underframe of the wagon. a double gear is used. the first is a spur gearing, connecting the motor to a countershaft placed under the motor. this gear reduces the speed of rotation to about revolutions. the countershaft is then connected to the two axles of the trolley by chain gearing. this gives the necessary flexibility between the car body and the wheel required, as the springs give to any inequality of the rails. in this gearing there is no change of speed. the underframe is provided with spring axle boxes, and also with spring buffers and drawbars. the speed of the motor can be regulated within very wide limits by the regulator, r. an effective hand brake is also provided. [illustration: fig. .--end elevation of locomotive.] [illustration: fig. .--detailed elevation of a koppel locomotive with a double platform and hood.] for gages of inches and upward the motors can be mounted on springs and attached to the running axles inside of the wagon underframe. this construction is particularly recommended by mr. koppel where, in order to mount heavy gradients, the dead load of the motor car must be assisted by the paying load to produce the necessary adhesion. in such cases several motor wagons would be used in the same train. as regards the working voltage, this can be varied to suit special requirements, but the locomotive we illustrate was designed for volts. at this pressure its possible working speed was at least eight miles per hour. the supply of power is also a matter not referred to particularly, as in many cases a lighting plant is used by the contractors, which could also be employed to provide the necessary energy for the electric railway. the good work done by small electric locomotives in the excavation work for the waterloo and city railway[ ] will convince our large contractors of the valuable service which electricity can render both above and below ground.--the electrical engineer. [footnote : electrical engineer, vol. xvi., p. .] * * * * * a connection between servian and roumanian railways is to be established by bridging the danube. it is reported proposals have already been made to the governments interested, by the union bridge company, also by british and french constructors.--uhland's wochenschrift. * * * * * liquid rheostats. by h. s. webb.[ ] [footnote : in american electrician.] the object in view when the following tests were commenced was to obtain some data from which the dimensions of a liquid rheostat for the dissipation as heat of a given amount of energy could be calculated, or at least estimated, when the maximum current and e.m.f. are known. these tests were rather hastily made and are far from being as complete as i should like to have them, and are published only to answer some inquiries for information on the subject. in the first test, an ordinary daniell jar ( ¼ inches in diameter by inches deep) with horizontal sheet iron electrodes was filled with tap water. it would not carry amperes for over fifteen or twenty minutes, although the jar was full of water and the plates only ¾ inch apart. after that length of time it became too hot, causing great variation in the current on account of the large amount of gas liberated, much of which adhered to the under surface of the upper electrode. the difference of potential between the plates was volts. a run was made with ampere and then with amperes for one hour. in the latter case the voltage between the electrodes was about volts and the temperature rose to about ° f. from these tests it would be safe to allow a vessel with a cross section of . square inches to carry from to ½ amperes when tap water and horizontal electrodes are used. in test no. the same jar and electrodes were used as in the preceding test, but the tap water was replaced by a saturated solution of salt water. eleven amperes with a potential difference of volts between the electrodes, which were ¾ inches apart, were passed through the solution for three hours, and the temperature at the end of the run was ° f., and was rising very slowly. although the current per square inch is much greater, the watts absorbed per cubic inch is much less in this case than when water was used. with the water carrying amperes the watts absorbed would be over per cubic inch, while for the saturated solution of salt when carrying amperes it would be only about . watt. in test no. use was made of a long, wooden rectangular trough ( inches by ½ inches by inches) with vertical, sheet iron electrodes. the cross section of the liquid, which was a per cent. solution of salt in water, was square inches, and with amperes passing through the solution for ¾ hours the temperature rose to ° f., and was rising slowly at the end of the run. the plates were ¾ inches apart, and at the end of the run the voltmeter across the terminals read . this gives a current density of nearly ¼ ampere per square inch and . watt per cubic inch. these values are too low to be considered maximum values, for this cross section of a per cent. salt solution would probably carry to amperes safely. it appears that as the amount of salt in the solution is increased from zero to saturation, the maximum current carrying capacity is increased, but the watts absorbed per cubic inch are less. a very small addition of salt to tap water makes the solution a much better conductor than the water, and reduces greatly the safe maximum watts absorbed. in using glass vessels, such as daniell jars, there is danger of cracking the jar if the temperature rises much above ° to ° f. in test no. an ordinary whisky barrel, filled up with tap water, was used. two horizontal circular iron plates ( / inch thick) were used for electrodes. the diameter of the inside of the barrel was approximately - / inches. with the two plates - / inches apart a difference of potential of volts gave a current of . amperes. with the plates / inch apart, volts gave . amperes at the end of one hour, when all the water in the barrel was very hot ( ° f.), and there was quite a good deal of gas given off. the current density in this case was about . ampere per square inch and the watts absorbed . per cubic inch. if it were not for the large amount of water above both electrodes, it is doubtful if this current density could have been maintained. in test no. a rectangular box, in which were placed two vertical sheet iron plates, was filled with tap water. the distance between the plates was / inch, and with a difference of potential of at start and at end of the run, a current of amperes was kept flowing for minutes. cold tap water was kept running in between the electrodes at the rate of . pounds per minute (about / cubic foot) by means of a small rubber tube about / inch inside diameter. this test is very interesting in comparison with the preceding. the current carrying capacity, . ampere per square inch, was more than double, and the energy absorbed watts per cubic inch, more than six times as great as in case where running water was not used. the temperature in some places between the plates occasionally rose as high as ° f., and it was necessary, in order to avoid too violent ebullition, to keep the inflowing stream of water directed along the water surface between the two plates. less water would not have been sufficient, and, of course, by using more water, the temperature could have been kept lower, or with the same temperature the watts absorbed could have been increased. when a large current density is used, there is considerable decomposition of the iron electrodes when either salt or pure water is used, and in the case of horizontal electrodes, the under surface of the top plate may become covered with bubbles of gas, making the resistance between the plates quite variable. for large current density a horizontal top plate is not advisable, unless a large number of holes are drilled through it. a better form for the top electrode would be a hollow cylinder long enough to give sufficient surface. washing soda is often a convenient substance to use instead of salt. if, from experience, the size of a liquid rheostat for absorbing a given amount of energy cannot be estimated, the dimensions may be calculated approximately as follows: suppose, for instance, it is desired to absorb amperes at volts difference of potential between the electrodes. now, it is inconvenient to obtain a saturated solution of salt, and to use tap water would require too large a cross section--especially if a barrel or trough is to be used--in order to have the resistance with the plates at a safe distance apart, small enough to give amperes with volts. let us try a per cent. solution of salt. suppose the maximum current this will carry is ¼ ampere per square inch, which will give a cross section of the solution of at least ÷ ¼ = square inches. now, the specific resistance per inch cube (i.e., the resistance between two opposite surfaces of a cube whose side measures inch) of the per cent. solution of salt used in test no. was . ohms. the drop, cr, will be . × ¼ = . volt per inch length of solution between electrodes. hence, the electrodes will have to be / . = inches apart. this would require about three barrels connected in series. this was taken merely as an illustration, because its specific resistance was known when the current density was ¼ ampere per square inch. this solution, however, will carry safely / ampere per square inch, but i used the previous figure, since i did not know its specific resistance for this current density, because its specific resistance will be lower for a larger current density on account of the higher temperature which it will have, for the resistance of a solution decreases as its temperature increases. to reduce this length would require a solution of higher specific resistance, that is, a solution containing less than per cent. of salt, and an increase in the cross section, since the maximum carrying capacity also diminishes as the percentage of salt diminishes. only approximate calculations are useful because variations in temperature, amount of salt actually in solution and the rate at which heat can be radiated, all combine to give results which may vary widely from those calculated. as a matter of fact, it is seldom necessary or advisable to use a solution containing over or per cent. of salt. the best way to add salt to a liquid rheostat is to make a strong solution in a separate vessel and add as much of this solution as is needed. this avoids the annoying increase in conductivity of the solution which happens when the salt itself is added and is gradually dissolved. liquid rheostats are ever so much more satisfactory for alternating than for direct current testing. the electrodes and solution are practically free from decomposition, and a given cross section seems to be able to carry a larger alternating than direct current--probably due partly to the absence of the scum on the surface which hinders the radiation of heat. * * * * * the progress of medical education in the united states. a retrospective survey of the progress made and of the reforms instituted in medical education in the united states is instructive. in many respects there is cause for much congratulation, while for other reasons the situation gives rise to feelings of alarm. it is pleasing to note and it augurs well for the future that a decided advance has been made in the direction of a more thorough medical training, yet at the same time it is discouraging to observe that, despite these progressive steps, competition does not abate, but rather daily becomes more acute. dr. william t. slayton has just issued his small annual volume on "medical education and registration in the united states and canada." from a study of this book, which fairly bristles with facts, a sufficiently comprehensive opinion may be formed in regard to the present state of medical education in this country. according to this work, there is now a grand total of one hundred and fifty-four medical schools. of this number, one hundred and seventeen require attendance on four annual courses of lectures, and twenty-seven require attendance on sessions of eight months, and ten on nine months each year. twenty-nine states and the district of columbia require an examination for license to practice medicine; eighteen of these require both a diploma from a recognized college and an examination. fifteen states require a diploma from a college recognized by them or an examination. five states, viz., vermont, michigan, kansas, wyoming and nevada, have practically no laws governing the practice of medicine; alaska the same. in order to gain a clear comprehension of the existing state of affairs, a comparison of the number of students at two periods, with a lapse of years intervening sufficient to eliminate all minor variations, will be more to the point than merely regarding the multiplication of schools. many of these mushroom institutions are not worthy of notice, containing perhaps a dozen students, and brought into existence only for the purpose of profit or from other motives of self-interest. the number of students is as reliable an index as can be given. for instance, taking the decade between - and - , it will be found that the students in regular schools in - numbered , ; in - they had increased to , . students in homoeopathic schools in - were , ; in - , , . the number of eclectic students was stationary at the two periods. the increase during the period from - to the present time has been at about the same ratio. these figures reveal more plainly than words the existing condition of affairs, which must, too, in the nature of things, continue until that time when all the states fall into line and resolve to adopt a four years' course of not less than eight months. to make yet another comparison, the total number of medical schools in austria and germany, with a population exceeding that of this country, is twenty-nine. great britain, with more than half the population, has seventeen; while russia, with one hundred million inhabitants, has nine. of course we do not argue that america, with her immense territory and scattered population, does not need greater facilities for the study of medicine than do thickly inhabited countries, as germany and great britain; but we do contend that when a city of the size of st. louis has as many schools as russia, the craze for multiplying these schools is being carried to absurd and harmful lengths. however, that the number of schools and their yearly supply of graduates of medicine are far beyond the demand is perfectly well known to all. the medical record and other medical journals have fully discussed and insisted upon that point for a considerable time. the real question at issue is by what means to remedy or at least to lessen the bad effects of the system as quickly as possible. the first and most important steps toward this desirable consummation have been already taken, and when a four years' course comes into practice throughout the country, the difficult problem of checking excessive competition will at any rate be much nearer its solution. why should france, germany, great britain and other european nations consider that a course of from five to seven years is not too long to acquire a good knowledge of medical work, while in many parts of america two or three years' training is esteemed ample for the manufacture of a full-fledged doctor? such methods are unfair both to the public and to the medical profession, and the result is that in numerous instances the short-time graduate has either to learn most of the practical part of his duties by hard experience, to starve, or to utilize his abilities in some more lucrative path of life. taking into consideration the fact that the theory and practice of medicine have become so extended within recent years, it must be readily conceded that four years is barely sufficient time in which to gain a satisfactory insight into their various departments. for a person, however gifted, to hope to receive an adequate medical training in two or three years is vain. in those states in which the facilities for securing a medical education are abundant, and where the time and money to be expended are within the reach everyone, there is always the danger that an undue proportion will forsake trade in order to join the profession. this is especially the case when times are bad. many persons seem to be possessed of the idea that the practice of medicine as a means of livelihood should be regarded as a something to fall back upon when other resources fail. accordingly, when trade is depressed and money is scarce, there is a rush to enter its ranks. that this view of the matter is altogether an erroneous one is too self-evident to need any demonstrative proof. again, although the question of a universal four years' course is a most important one, it must not be forgotten that examination takes almost as conspicuous a place. it is desirable that every one entering on medical studies should possess a general education. with the exception of a few unimportant schools, the entrance examinations would appear to afford the necessary test. then comes the much more vital point of how to gage, in the fairest possible manner, the extent of the medical knowledge of those who have undergone their full term of study. for various reasons the conducting of the final examinations by professors in the school in which the student has been taught is open to many and grave objections, more especially when these professors are themselves teachers in that school. as has been pointed out in the medical record on more than one occasion, the most obviously fair regulation is that of independent examination by an unbiased state board. if this plan were carried into execution, medical education in america generally would rest on a firmer basis than in great britain, in which country the standard, although nowhere so low as in parts of the united states, still varies very considerably in the different schools. the general medical council of england has arrived at the conclusion that competition must be checked, and has lately brought into force two drastic measures calculated to attain this object; one is the lengthening of the course to five years, and, more recently, the abolishing of the unqualified assistant. the medical profession of america is quite as conscious of the disastrous results of competition as are its fellow practitioners on the other side, and should use every legitimate means to sweep away the evils of the present system.--medical record. * * * * * deaths under anÆsthetics. on december , , a fatality occurred during the administration of ether. the patient, a woman aged forty-four years, who suffered from "internal cancer," was admitted for operation into the new hospital for women, euston road. it was considered that an operation would afford a chance of the prolongation of her life. at the time of admission the patient was in a very exhausted condition. mrs. keith, the anæsthetist to the hospital, administered nitrous oxide gas, followed by ether, which combination of anæsthetics the patient took well. after the expiration of thirty minutes and while the operation was in progress the patient became so collapsed that the surgeon was requested by the anæsthetist to desist from further surgical procedure and she at once complied. resuscitative measures were at once applied, but the patient died after about ten minutes from circulatory failure arising from surgical shock and collapse. we have not received any particulars as to the means adopted to restore the woman or whether hemorrhage was severe. in all such cases posture, warmth and guarding the patient from the effects of hemorrhage are undoubtedly the most important points for attention both before and during the operation. the fact is established that both chloroform and ether cause a fall of body temperature, and so increase shock unless the trunk and limbs are kept wrapped in flannel or cotton-wool. the fall of temperature under severe abdominal and vaginal operations again is considerable. a profound anæsthesia allows of a considerable drop in arterial tension, which has been shown to be least when the limbs and pelvis are placed at a higher level than the head. again, saline transfusion of ringer's fluid certainly lessens the collapse in such cases when the bleeding, always severe, has been excessive. we do not doubt that such a severe operation undertaken when the patient was in a dangerous state of exhaustion was as far as possible safeguarded by every precaution, and we regret we have not been favored with the particulars of the methods employed. a death following the administration of ether is reported from the corbett hospital, stourbridge.[ ] the patient, aged thirty-nine years, was admitted on september , , suffering from fracture of the right femur. a prolonged application of splints led to a stiffness with adhesions about the knee joint which were to be dealt with under an anæsthetic on december . ether was given from a clover's inhaler; one ounce was used. the induction was slightly longer than usual but was marked by no unusual phenomena. no sickness occurred during or after anæsthesia and no respiratory spasm was seen. there was a short struggling stage followed by true anæsthesia when the operation, a very brief one, was rapidly performed. the patient was then taken back to the ward and the corneal reflex was noticed as being present. voluntary movements were also said to have been seen. later he opened his eyes "and seemed to recognize an onlooker." after this no special supervision was exercised. a hospital porter engaged in the ward noticed the man was breathing in gasps; this was twenty minutes after the patient had been taken from the operating theater and half an hour subsequent to the first administration of the ether. the surgeons were fetched from the operating theater and found by that time that the man was dead. "he was lying with his head thrown back, so that no possible difficulty of breathing could have arisen due to his position. the eyes were open and the lips slightly parted; nor was there any sign of any struggle for breath having taken place." the ether was analyzed and found to fulfill the british pharmacopoeia tests for purity. the necropsy revealed that the right heart was distended with venous fluid blood. the lungs also were loaded with blood, as were all the viscera. we cannot but feel that the fact shown at the post mortem examination seemed to indicate that the man died from asphyxia and not from heart failure. no doubt patients appear to resume consciousness after an anæsthetic and even mutter semi-intelligible words and recognize familiar faces. they then sink into deep sleep just like the stupefaction of the drunken, and in this condition the tongue falls back and the slightest cause--a little thick mucus or the dropping of the jaw--will completely prevent ventilation of the lungs taking place. two very similar cases occurred in the practice of a french surgeon, who promptly opened the trachea and forced air into the lungs, with the result that both patients survived. in his cases chloroform had been given. a death under chloroform occurred at the infirmary, kidderminster. the patient, a boy, aged eight years and nine months, suffered from a congenital hernia upon which it became necessary to operate for its radical cure. the house surgeon, mr. oliphant, m.b., c.m. edin., administered chloroform from lint. in about eight minutes the breathing ceased, the operation not having then been commenced. upon artificial respiration being adopted the child appeared to rally, but sank almost immediately and died within two minutes. the necropsy showed no organic disease. at the inquest the coroner asked dr. oliphant whether an inhaler was not a better means of giving chloroform, and whether that substance was not the most dangerous of the anæsthetics in common use, and received the answer that inhalers were not satisfactory for giving chloroform and that it was a matter of opinion as to which was the most dangerous anæsthetic. we so often hear that the scotch schools never meet with casualties under anæsthetics because they always use chloroform, and prefer to dispense with any apparatus, that we can readily accept the replies given to the coroner as representing the views current among the majority of even the thoughtful alumni of those great centers of medical training. a glance over the long list of casualties under chloroform will unfortunately show that whatever charm syme exercised during his life has not survived to his followers, and overdosage with chloroform proves as fatal in the hands of those who hail from beyond the tweed as well as "down south." a death from chloroform contained in the a.c.e. mixture occurred at the general hospital, birmingham, on december . the patient, a girl, aged five years and ten months, suffered from hypertrophied tonsils and post-nasal adenoid growths. she was given the a.c.e. mixture by mr. mccardie, one of the anæsthetists to the institution, and tonsillotomy was performed. as consciousness was returning some chloroform was given to enable mr. haslam, the operator, to remove the growths. she died at once from respiratory failure, in spite of restorative measures. a necropsy showed absence of organic disease. the anæsthetist regarded the death as one from cardiac failure due to reflex inhibition by irritation of the vagus. we are not told the posture of the child or the method employed.--the lancet. [footnote : we are indebted to mr. hammond smith, honorary surgeon to the hospital, and mr. edgar collis for the notes of the case.--ed. lancet] * * * * * the resistance of nickel steel to the attack of water increases with the nickel contents. the least expanding alloys, containing about per cent. of nickel, are sufficiently unassailable, and can be exposed for months to air saturated with moisture without being tainted by rust. with a view of testing the expansion of nickel steel, experiments have been carried out by allowing measuring rods to remain in warm water for some hours, according to the iron and coal trades review. they were not wiped off when taken out, but were exposed for a longer period to hot steam, but the lines traced on the polished surfaces were not altered. the rough surfaces, when exposed to steam, were covered after several days with a continuous, but little adhesive, coat of rust. * * * * * recent books applied mechanics. a treatise for the use of students who have time to work experimental, numerical, and graphical exercises illustrating the subject. by john perry. with illustrations. mo, cloth. pages. london, . $ architecture. architectural drawing for mechanics. by i. p. hicks. a comprehensive treatise on architectural drawing for building mechanics, showing the learner how to proceed step by step in every detail of the work. square mo, cloth. illustrations. pages. new york, . $ architecture. the planning and construction of high office buildings. by w. h. birkmire. vo, cloth. illustrated. pages. new york, . $ arches. a treatise on arches. designed for the use of engineers and students in technical schools. by m. a. howe. vo, cloth. new york, . $ asbestos and asbestic. their properties, occurrence and use. by r. h. jones. with collotype plates and other illustrations. vo, cloth. london, . $ assaying. a manual of assaying gold, silver, lead, copper. by walter lee brown. seventh edition. pages. illustrated. mo. cloth. chicago, . $ astronomy. a new astronomy. by david p. todd. mo, cloth. pages. profusely illustrated. new york, . $ beverages. standard manual for soda and other beverages. a treatise especially adapted to the requirements of druggists and confectioners. by a. emil hiss. mo, cloth. pages. chicago, . $ bicycle repairing. a manual compiled from articles in "the iron age." by s. d. v. burr. vo, cloth. pages. fully illustrated. new york. $ boot making and mending. including repairing, lasting and finishing. with numerous engravings and diagrams. edited by paul n. hasluck. 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[illustration] scientific american supplement no. new york, march , scientific american supplement. vol. xxxi., no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents i. botany.--new race of dwarf dahlias.--a new and valuable flowering plant, with portrait of the introducer.-- illustration. ii. chemistry.--carbon in organic substances.--by j. messinger.-- an improved method of determining carbon by inorganic combustions.-- illustration. iii. civil engineering.--a new integrator.--by prof. karl pearson. m.a.--an apparatus for use for the engineer in working up areas, indicator diagrams, etc.-- illustrations. best diameter of car wheels.--the size of car wheels from the standpoint of american engineering.--a plea for a moderate sized wheel. improved overhead steam traveling crane.--a crane constructed for use in steel works.--great power and range.-- illustrations. some hints on spiking track.--a most practical article for telling exactly how to conduct the operation on the ground.-- illustration. iv. electricity.--electrical laboratory for amateurs.--by geo. m. hopkins.--a simple collection of apparatus for conducting a complete series of electrical experiments.-- illustrations. the action of the silent discharge on chlorine.--how an electric discharge affects chlorine gas.--an important negative result. v. ethnology.--some winnebago arts.--an interesting article upon the arts of the winnebago indians.--a recent paper before the new york academy of sciences. vi. medicine and hygiene.--the philosophy of consumption. --by dr. j.s. christison.--a review of the present theories of consumption, and the role played in it by its bacillus. vii. music.--spacing the frets on a banjo neck.--by prof. c.w. maccord.--a most practical treatment of this subject, with full explanations.-- illustration. viii. ordnance.--high explosives in warfare.--by commander f.m. barber, u.s.n.--an elaborate review of modern explosives in their applicability to ordnance, etc. the experiments at the annapolis proving grounds.--the recent tests at annapolis described and illustrated.--views of the projectiles, plates, etc.-- illustrations. ix. physics.--aræo-picnometer.--an entirely novel form of hydrometer, of very extended use and application.-- illustration. x. technology.--fabric for upholstery purposes.--full technical description of the method of producing a new and characteristic fabric.-- illustration. gaseous illuminants.--by prof. vivian b. lewes.--continuation of this important article, treating of the water gas and special processes, with analyses. glove making.--early history of glove making in america.--its present aspects and processes. reversible ingrain or pro-brussels carpet.--an imitation of brussels carpet on the ingrain principle.--full description of the process of making.-- illustrations. the manufacture and use of plaster of paris.--an excellent treatment of a subject hitherto little written about.--full particulars of the manufacturing process. * * * * * improved overhead steam traveling crane. we show in fig. a general view, and in figs. and a side elevation and plan of an overhead steam traveling crane, which has been constructed by mr. thomas smith, of rodley, near leeds, for use in a steel works, to lift, lower, and travel with loads up to tons. for our engravings and description we are indebted to _industries._ the crane is designed for hoisting and lowering while traveling transversely or longitudinally, and all the movements are readily controlled from the cage, which is placed at one end of and underneath the transverse beams, and from which the load can be readily seen. all the gear wheels are of steel and have double helical teeth; the shafts are also of steel, and the principal bearings are adjustable and bushed with hard gun metal. this crane has a separate pair of engines for each motion, which are supplied with steam by the multitubular boiler placed in the cage as shown. the hoisting motions consist of double purchase gearing, with grooved drum, treble best iron chain with block and hook, driven by one pair of in. by in. engines. the transverse traveling motion consists of gearing, chain, and carriage on four tram wheels, with grooved chain pulleys, driven by the second pair of in. by in. engines, and the longitudinal traveling motion driven by the other pair of in. by in. engines. the transverse beams are wrought iron riveted box girders, firmly secured to the end carriages, which are mounted on four double flanged steel-tired wheels, set to suit a foot span. [illustration: improved overhead traveling crane] [illustration: fig. side elevation] [illustration: fig. plan] * * * * * best diameter car wheels.[ ] [footnote : by samuel porcher, assistant engineer motive power department, pennsylvania railroad. read at a regular meeting of the new york railroad club, feb. , .] it goes almost without saying that for any given service we want the best car wheel, and in general it is evident that this is the one best adapted to the efficient, safe and prompt movement of trains, to the necessary limitations improved by details of construction, and also the one most economical in maintenance and manufacture. it is our aim this afternoon to look into this question in so far as the diameter of the wheel affects it, and in doing it we must consider what liability there is to breakage or derangement of the parts of the wheel, hot journals, bent axles, the effect of the weight of the wheel itself, and the effect upon the track and riding of the car, handling at wrecks and in the shop, the first cost of repairs, the mileage, methods of manufacture, the service for which the wheel is intended and the material of which it is made. confining ourselves to freight and passenger service, and to cast iron and steel wheels in the general acceptation of the term as being the most interesting, we know that cast iron is not as strong as wrought iron or steel, that the tendency of a rotating wheel to burst is directly proportional to its diameter, and that the difficulty of making a suitable and perfect casting increases with the diameter. cast iron, therefore, would receive no attention if it were not for its far greater cheapness as compared to wrought iron or steel. this fact makes its use either wholly or in part very desirable for freight service, and even causes some roads in this country, notably the one with which i am connected, to find it profitable to develop and perfect the cast iron wheel for use in all but special cases. steel, on the other hand, notwithstanding its great cost, is coming more and more into favor, and has the great recommendations of strength and safety. it is also of such a nature that wheels tired with it run much further before being unfit for further service than those made of cast iron, and consequently renewals are less frequent. the inference would seem to be that a combination of steel and cast iron would effect the desirable safeness with the greatest cheapness; but up to the present this state of affairs has not yet been realized to the proper extent, because of the labor and cost necessary to accomplish this combination and the weakness involved in the manner of joining the two kinds of material together. taking up the consideration of the diameter of the wheel now, and allowing that on the score of economy cast iron must be used for wheels in freight service, we are led to reflect that here heavy loads are carried, and there is a growing tendency to increase them by letting the floor of the car down to a level with the draft timbers. all this makes it desirable to have the wheels strong and small to avoid bent axles and broken flanges, to enable us to build a strong truck, to reduce the dead weight of cars to a minimum, and have wrecks quickly cleared away. the time has not yet come when we have to consider seriously hot journals arising from high speed on freight trains, and a reasonable degree only of easy riding is required. the effect on the track is, however, a matter of moment. judging from the above, i should say that no wheel larger than one in. in diameter should be used under freight cars. since experience in passenger service shows that larger cast iron wheels do not make greater mileage and cost more per , miles run, and that cast iron wheels smaller than in., while sometimes costing less per , miles run, are more troublesome in the end, it is apparent that in. is the best diameter for the wheels we have to use in freight service. when we take up passenger service we come to a much more difficult and interesting part of the subject, for here we must consider it in all its bearings, and meet the complications that varying conditions of place and service impose. in consequence, i do not believe we can recommend one diameter for all passenger car wheels although such a state of simplicity would be most desirable. for instance, in a sandy country where competition is active, and consequently speed is high and maintained for a length of time without interruption, i would scarcely hesitate to recommend the use of cast iron for car wheels, because steel will wear out so rapidly in such a place that its use will be unsatisfactory. if then cast iron is used, we will find that we cannot make with it as large a wheel as we may determine is desirable when steel is used. and just to follow this line out to its close i will state here that we find that in. seems to be the maximum satisfactory diameter for cast iron wheels, because this size does not give greater mileage than in., costs more per , miles run, and seems to be nearer the limit for good foundry results. on the other hand, a in. wheel rides well and gives immunity from hot boxes--a most fruitful source of annoyance in sandy districts. it is also easily applicable where all modern appliances under the car are found, including good brake rigging. in all passenger service, then, i would recommend in. as the best diameter for cast iron wheels. next taking up steel wheels, a great deal might be said about the different makes and patterns, but as the diameter of wheels of this kind is not limited practically to any extent by the methods of manufacture, except as to the fastening of the wheel and tire together, we will note this point only. tires might be so deeply cut into for the introduction of a retaining ring that a small wheel would be unduly weakened after a few turnings. on the other hand, when centers and tires are held together by springing the former into the latter under pressure, it is possible that a tire of larger diameter might be overstrained. but allowing that the method of manufacture does not limit the diameter of a steel wheel as it does a cast iron one, the claim that the larger diameter is the best is open to debate at least, and, i believe, is proved to the contrary on several accounts. it is argued that increasing the diameter of a wheel increases its total mileage in proportion, or even more. whether this be so or not, there are two other very objectionable features that come with an increase in diameter--the wheel becomes more costly and weighs more, without giving in all cases a proportionate return. we have to do more work in starting and stopping, and in lifting the large wheel over the hills, and when the diameter exceeds a certain figure we have to pay more per , miles run. i am very firmly convinced that the matter of dead weight should receive more attention than it does, with a view to reducing it. the weight of six pairs of in. wheels and axles alone is , to , lb. the matter of brakes is coming up for more attention in these days of high speed, heavy cars and crowded roads, and the total available braking power, which has hitherto been but partially taken advantage of, must be fully utilized. i refer to the fact that many of our wheels in six-wheel trucks have gone unbraked where they should not. as the height of cars and length of trucks cannot well be increased for obvious reasons, it is necessary to keep the size of the wheels within the limits that will enable us to get efficient brakes on all of them that carry any weight. this is not easy with a in. wheel in a six-wheel truck, which is usually the kind that requires most adjustment and repairs after long runs. the pullman co. has recognized this fact, and is now replacing its in. wheel with one in. in diameter. a in. wheel with in. journal has a greater leverage wherewith to overcome the resistance of journal friction than the in. wheel with the same journal, and even more than the in. and in. wheels with / in. and / in. journals respectively, but the fact remains that the same amount of work has to be done in overcoming the friction in each case, and what may be gained in ease of starting with the large wheel is lost in time necessary to do it, and in the extra weight put into motion. a large wheel increases the liability to bent axles in curving on account of greater leverage unless the size and weight of the axle are increased to correspond, and the wheel itself must be made stronger. a four or six wheel truck will not retain its squareness and dependent good riding qualities so well with in. wheels as with in. ones. besides the brakes, the pipes for air and steam under the cars interfere with large wheels, and as a consequence of all this in. wheels have been replaced by in. ones to some extent in some places with satisfactory results. on one road in particular so strong is the inclination away from large wheels that in. is advocated as the proper size for passenger cars. on the other hand, there is no doubt a car wheel may be too small, for the tires of small wheels probably do not get as much working up under the rolls, and therefore are not as tough or homogeneous. small wheels are more destructive to frogs and rail joints. they revolve faster at a given speed, and when below a certain size increase the liability to hot journals if carrying the weight they can bear without detriment to the rest of the wheel. speed alone i am not willing to admit is the most prolific source of hot boxes. the weight per square inch upon the bearing is a very important factor. i have found by careful examination of a great many cars that the number of hot boxes bears a close relation to the weight per square inch on the journal and the character of lubrication, and is not so much affected by the size of wheel or speed. these observations were made upon in., in. and in. wheels in the same trains. we find, furthermore, that while a - / in. journal on a in. wheel is apt to heat under our passenger coaches, a / in., even when worn - / in., journal on a in. wheel runs uniformly cool. in on one division there were about hot boxes with the small wheel, against with the larger one, with a preponderance of the latter size in service and cars of the same weight over them. i do not know that there is any more tendency for a large wheel to slide than a small one under the action of the brakes, but large wheels wear out more brake shoes than small ones, if there is any difference in this particular. my conclusions are that in. is too large a diameter for steel wheels in ordinary passenger service, and that in. is right. but as steel-tired wheels usually become in. smaller in diameter before wearing out, the wheel should be about in. in diameter when new. such a wheel can be easily put under all passenger cars and will not have become too small when worn out. a great many roads are using in. wheels, but when their tires have lost in. diameter they have become in. wheels, which i think too small. there are many things i have left unsaid, and i am aware that some of the members of the club have had most satisfactory service with in. wheels so far as exemption from all trouble is concerned, and others have never seen any reason for departing from the most used size of in. one more word about lightness. a wrought iron or cast steel center, or light spokes on a light rim inside a steel tire, makes the lightest wheel, and one that ought to be in this country, as it is elsewhere, the cheapest not made of cast iron. * * * * * a new integrator.[ ] [footnote : a paper read before the university college engineering society on january .--_engineering_.] by professor karl pearson, m.a. as i fear the title of my paper to our society to-night contains two misstatements of fact in its three words, i must commence by correcting it. in the first place, the instrument to which i propose to draw your attention to-night is, in the narrow sense of the words, neither an integrator nor new. the name "integrator" has been especially applied to a class of instruments which measure off on a scale attached to them the magnitude of an area, arc, or other quantity. such instruments do not, as a rule, represent their results graphically, and we may take, as characteristic examples of them, amsler's planimeter and some of the sphere integrating machines. an integrator which draws an absolute picture of the sum or integral is better termed an "integraph." the distinction is an important and valuable one, for while the integraph theoretically can do all the work of the integrator, the latter gives us in niggardly fashion one narrow answer, _et præterea nil_. the superiority of the integraph over the integrator cannot be better pointed out than by a concrete example. the integrator could determine by one process, the bending moment, from the shear curve, at any one chosen point of a beam; the integraph would, by an equally simple single process, gives us the bending moment at all points of the beam. in the language of the mathematician, the integrator gives only that miserly result, a definite integral, but the integraph yields an indefinite integral, a picture of the result at all times or all points--a much greater boon in most mechanical and physical investigations. members of our society as students of university college have probably become acquainted with a process termed "drawing the sum curve from the primitive curve." many have probably found this process somewhat wearisome; but this is not an unmixed evil, as the irksomeness of any manual process has more than once led to the invention of a valuable machine by the would-be idler. thus our innate desire to take things easy is a real incentive to progress. it was some such desire as this on my part which led me, three years ago, to inquire whether a practical instrument had not been, or could not be, constructed to draw sum curves. such an instrument is an integraph, and the one i have to describe to you to-night is the outcome of that inquiry. it is something better than my title, for it is an integraph, and not an integrator. [illustration: a new integrator] before i turn to its claims to be considered new, i must first remind you of the importance of an instrument of this kind to the draughtsman. i put aside its purely mechanical applications, where it has been, or can be, attached to the indicators of steam engines, to dynamometers, dynamos, and a variety of other instruments where mechanical integration is of value. these lie entirely outside my field, and i propose only to refer to a few of the possible services of the integrator when used by hand, and not attached to a machine. the simple finding of areas we may omit, as the planimeter will do that equally well. but of purely graphical processes which the integraph will undertake for us, i may mention the discovery of centroids, of moments of inertia (or second moments), of a scale of logarithms, of the real roots of cubic equations, and of equations of higher order (with, however, increasing labor). further, the calculation of the cost of cutting and embanking for railways by the method of bruckner & culmann, the solution of a very considerable number of rather complex differential equations, various problems in the storage of water, and a great variety of statistical questions may all be completely dealt with, or very much simplified by aid of the integraph. in graphical statics proper the integraph draws successively the curves of shear, bending moment slope, and deflection for simple beams; it does the like service for continuous beams, after certain analytical or graphical calculations have first been made; it can further lighten greatly the graphical work in the treatment of masonry arches and of metal ribs. in graphical hydrostatics it finds centers of pressure and gives a complete solution for the shear and bending moment, curves in ships, besides curves for their stability. in graphical dynamics the applications of the integraph seem still more numerous. it enables us to pass from curves of acceleration to curves of speed, and from curves of speed to curves of position. applied to the curve of energy of either a particle or the index point of a rigid body, it enables us by the aid of easy auxiliary processes to ascertain speeds and curves of action. in a slightly altered form, that of "inverse summation," we can pass from curves of action to curves of position, and deal with a great range of resisted motions, the analysis of which still puzzles the pure mathematician; the variations of motion in flywheels, connecting rods, and innumerable other parts of mechanism, may all be calculated with much greater ease by the aid of an integraph. shortly, it is the fundamental instrument of graphic dynamics. it would be needless to further multiply the instances of its application; the questions we have rather to ask are: can a practical instrument be made which will serve all these purposes? has such an instrument been already put upon the market? if i have to answer these questions in the negative, it is rather a doubtful negative, for the instrument i have to show you to-night goes so far, and suggests so many modifications and possibilities, which would take it so much further, that it is very close to bringing the practical solution to the problem. let me here lay down the conditions which seem essential to a practical integraph. these are, i think, the following: . the price must be such that it is within the reach of the ordinary draughtsman's pocket. the amsler's planimeter at £ s. or £ may be said to satisfy this first condition. the price for the first complex integraph designed by coradi was £ to £ . the modified form in which i show it to-night is estimated to cost retail £ . till an equally efficient instrument can be produced for £ i shall not consider the price practical. if the error of its reading be not sensibly greater than that of a planimeter, it is certainly worth double the money. . the instrument must not be liable to get out of order by fair handling and a reasonable amount of wear and tear. i cannot speak at present with certainty as to how far our integraph satisfies this condition; it is rather too complex to quite win my confidence in this respect. . it must be capable of being used on the ordinary drawing board, and of having a fairly wide range on it, i.e., it must not be limited to working where the primitive is at one part only of the board. this condition takes out of every day practical drawing use the integraph invented by professors james and sir william thomson, in which the sum curve is drawn on a revolving cylinder. it is essential that the sum curve should be drawn on the board not far from the primitive, and that this sum curve can be summed once or twice again without difficulty. the time involved in drawing the four sum curves, for example, required in passing from the load curve to the deflection curve of a simple beam, if these curves were drawn on different pieces of paper and had to be shifted on and off cylinders, would probably be as long as the ordinary graphical processes. coradi's integraph works on an ordinary drawing board, but since there are nearly inches between the guide point and tracer, the sum curve is thrown inches behind the primitive in each integration. thus a double summation requires say inches of board, and it is impossible to integrate thrice without reproducing the primitive. the fact that the primitive and sum curve are not plotted off on the same base is also troublesome for comparison, and involves scaling of a new base for each summation. i have endeavored to obviate this by always drawing the second sum curve on a thin piece of paper pinned to the board, which can then be moved back to the position of the first primitive. but this shifting, of course, involves additional labor, and is also a source of error. i should like to see the trace and guide chariots on the same line of rails, one below the other, were this possible without producing the bad effect of a skew, pull or push. . the practical integraph must not have a greater maximum error than per cent. the mathematical calculations, which are correct to five or six places of decimals, are only a source of danger to the practical calculator of stresses and strains. they tend to disguise the important fact that he cannot possibly know the properties of the material within per cent. error, and therefore there is not only a waste of time, but a false feeling of accuracy engendered by human and mechanical calculation which is over-refined for technical purposes. for comparative purposes i have measured the areas of circles of inch, inches, and inches radius, the guide being taken round the circumference by means of a "control lineal," first with an ordinary amsler's planimeter and then with the integraph. i have obtained the following results: ---------+------------+-----------+----------------------------------- | | | by integraph. radius | | by |--------+--------+--------+-------- of | calculated |planimeter.| | upper | | upper circle. | areas. | |middle. | end. |middle. | end. | | |p= in. |p= in. |p= in. |p= in. ---------+------------+-----------+--------+--------+--------+-------- in. | | | | | | | . | . | . | . | . | . | | | | | | | . | . | . * | . | . | . | | | | | | | . | . | ...... | ...... | . | . ---------+------------+-----------+--------+--------+--------+-------- * cross bar had to be moved during tracing. from this it follows that the error of the planimeter is less than . per cent. and that of the integraph about . per cent. obviously we could make this error much less if we excluded small areas measured with large polar distances, or such polar distances that the cross bar must be shifted. excluding such cases, we see that the accuracy of the integraph scarcely falls behind that of the planimeter and is quite efficient for practical purposes. it must be borne in mind that the above measurements were made with the "control lineal," an arrangement which carries the guide round a circle of the exact test area. in most cases the curve has to be followed by hand, and the error will be greater--greater probably for the integraph than for the planimeter, as the former is distinctly hard to guide well. i think, then, we should be safe in saying that the error of the integraph is not likely to be greater and is probably less than per cent., so that in this respect the instrument may be considered a practical one. . a further condition for a good integraph is that it should have a wide range of polar distances, and that it should be easily set at those distances. one of the conditions i gave to the maker of the instrument was that it should be able to take all polar distances from one to ten half-inches. this condition he can scarcely be said to have fulfilled. with polar distances of / inch and inch, the machine works unsatisfactorily, which indeed might have been foreseen from the construction of its sliding bars. it works best from . inches to inches, and this is the range to which i think we ought to confine the present type of instrument. as the last conditions i may note that: . a practical integraph ought to be easy to read. . draw a good clear curve. the scale on the present instrument is very inconvenient, as it is often almost out of sight; the curve it draws, on the other hand, i consider very satisfactory, when the pencil is loaded, say, with a planimeter weight. on the whole, i think you will agree with me that this integraph goes a good way, if not the whole way, toward fulfilling the conditions of a practical instrument. i next turn to its construction and the claim it has to be considered in any way new. let me briefly remind our members of the process by which an element q r of the sum curve (fig. ) corresponding to the point p on the primitive is drawn; p m being the mid-ordinate of l n, a horizontal element, p b is drawn perpendicular to any vertical line a b; and o a being a constant distance termed the base or "polar distance," q r is drawn between the ordinates of l and w, parallel to o b. if p' be the point where p m meets q r, we note the following relationship of p' to p. . if p moves along a horizontal line, o b remains unchanged, and, therefore, q r or p' must move in the straight line q r parallel to o b. . if p moves along a vertical line, p' does not change, but q r turns round it, remaining parallel to o b. [illustration: fig. , , ] without taking the trouble, as i ought to have done, to inquire what previous investigations had achieved in this matter, i thought, three years ago, i could get an apparatus to save me the trouble of drawing sum curves, made somewhat after the following fashion. p (fig. ) is the guide or point to be taken round the primitive. it is attached to a block, d, which works along the bar, b c, which in its turn moves on the four wheels, e e f f, upon the frame r s u t fixed upon the drawing board. o a is fixed perpendicular to r u, and is such that o may be fixed at various points to determine the polar distance. o b d is a light bar passing freely through b and forming one side of a parallel ruler of two or more points, g g, h h, i i. along i i is a slot and in this works a loaded block containing a wheel p', whose plane is always parallel to i i. this block also passes through a slot in d e, an arm at right angles to b c. a little consideration will show that p', if worked at all, would trace out the sum curve of p. it was only when i showed the rough idea of this to professor kennedy, with the view of ascertaining what would be the amount of back-lash and friction, that i learned that mr. boys had already invented a very similar integrator. in his model the double parallel ruler is replaced by two endless strings and pulleys, and the bar, b c, by a t square. although this integrator was afterward made in a less crude form, i do not think it has ever been a practical instrument for the draughtsman. shortly afterward i came across a work by abdank-abakanowicz, entitled "les integraphes," being a study of a "new kind of mechanical integrator." the new kind of integrator was really only an independent version of boys' instrument, but in many respects a great improvement. the real merit will ultimately belong to the scientific instrument maker who constructs an instrument reasonably cheap and capable of efficient practical service. abdank-abakanowicz's integrator however certainly went further in the practical direction than any previously constructed. the drawing board machines, it is true, of rather a complex nature, were actually exhibited to the paris academy, but no more have been made. the instrument before me was made by coradi, of zurich, on conditions laid down by me, namely, that the cost should not exceed £ , and that polar distances should range between one and ten half-inches. the first machine made by coradi on these lines was, by a misunderstanding, sold in germany, but the one i exhibit is the first, i believe, that has reached england, and to this extent i may, perhaps, be permitted to call it new. i look upon it rather as a suggestion upon which a still more practical instrument can be made in this country than as a perfect model. i believe there would be a wide sale for such an instrument were it once generally known to exist, and, what is more to work efficiently. it remains for me to point out in what the abdank-abakanowicz, or, rather, coradi, integraph differs from boys' instrument. two points deserve special attention. in the first place, the fixed frame is abolished, and the horizontal motion of p (fig. ), the guide point, is produced by putting the whole frame on friction rollers; in the second place, as a necessary result of the first change, the guide point carries about with it its own polar system, which renders the changes in length of "rays" much more manageable. f f, f' f' is a frame moving on four roughed wheels, e e e e, so that it can only move in the direction, f', which we may term horizontal. f f and f' f' are rails guiding the chariots, a and b, from f to f and from f' to f'. of these chariots, a contains the guide point, p, to trace out the primitive with, and b the pencil, p', to draw the sum curve, i.e., the tracer. the chariot, b, like boys' tracer, is heavily loaded. g g is a horizontal bar rigidly attached to the crossbars, q q and q' q', of the frame. on g g is a movable pivot, to which h, which determines the pole, k h being the polar distance. k is the position of a second point, k, on the chariot, a, when the guide point, p, is on the initial line, g g. l l is a bar with a long slot in it, in which work the pivots, h and k; this bar represents the "ray." a projecting arm k k' has been introduced to enable me to shorten the polar distance down to in. and under by removing the pivot, k to k'. m m is a bar attached to the block, n, which runs on l l, so that m m is always perpendicular to l l. on the chariot, b, is another bar, m' m', capable of turning round the pivot, d, and always maintained parallel to m m by the rods, m m', m m'. attached to m' m' is a wheel, w, whose axis is parallel to m' m'. this wheel, therefore, always moves perpendicular to m' m', and therefore to m m; hence it moves parallel to the ray, h k. a pencil, p', attached traces out the sum curve. if we wish to use the machine as an integrator, we have merely to measure the vertical distance traversed by p', or the distance b has run along f' f'. this is done by means of a scale on f f'. if k be brought down to k , w runs parallel to g g, or p' traces out a horizontal straight line, which is thus the base line. if k be fixed as near as possible to k , which is done by means of a screw in f f at k , the chariot, b, can be run down f' f' as nearly opposite to k as can be guessed at; a horizontal line may then be drawn as base line, and the guide point, p, brought into this line by a clamping screw with which it is provided. the instrument is then ready for action. there is a brake on one of the roughed wheels to check or stop the motion of the integraph when required. the instrument works best when the chariots, a and b, are about opposite to each other; when they are at opposite extremities of f f and f' f' respectively, the pull at p tends to produce a skewing couple. if the chariot, b, could be put upon f f and work, if needful, by a double parallelogram from m m, we should have, excepting the skew pull, some great practical advantages. we might throw the whole of the weight of the machine on the one pair of friction wheels, and replace the other pair by a single wheel, the portion q' f' f' q' of the machine virtually disappearing. three wheels, of course, would be a real improvement. further, we should have the sum curve and primitive drawn to the same base line, and the simplification in the number of parts ought largely to reduce the cost of the instrument. to be able to perform "inverse summation" (which in the language of differential calculus is to find y as a function of x, when we are given y=f(dy/dx), and not dy/dx=f(x) as usual), we only want a means of making the plane of the wheel, w, parallel instead of perpendicular to m' m', and it is easy to design a modification in the construction which will allow of this change. i hope the above description of the integraph may have made its construction and method of working sufficiently clear. those of you who have a taste for mechanical work, and the necessary tools, might, i think, with some patience, construct a workable integraph. i expect the pivots would be the hardest part of the work. i hope, some day, myself to have another instrument made with a more readily changeable polar distance, with trace and guide points working in the same vertical, and a wheel permitting of inverse summation. if this project is ever carried out, i hope i may be permitted to communicate further particulars to our society. * * * * * after some forty years of immersion in the waters of the pool of echoschacht, not far from hermannstadt, several human bodies have been brought to the surface in a state of perfect preservation. * * * * * some hints on spiking track. the usual dimensions of track spikes are / x . inches square, their weight about half a pound each. their common defects are brittleness and imperfect points. in spiking track, the most important points to be attended to are the proper spacing of the ties and driving the spikes in such a manner that the ties shall be held in place at right angles to the track and the rails in true gauge; to insure the latter, the track gauge should always be used when spiking the gauge side, the rail being held to proper position by a lining bar. the gauge should be kept about or in. ahead of the tie being spiked and should not be lifted until the spikes are driven home; gauges should be tested regularly and every morning when they are to be used all day, so as to insure a true gauge all the time. the two inner spikes should be set on one side of the tie and the two outer spikes on the other, as indicated in the accompanying sketch. this prevents the tie from slewing around, and thus deranging the gauge of the track, as well as interfering with the proper spacing of the ties. the joints and centers should be spiked first, which will bring the rails to their proper position on the ties, which in turn will assist intermediate spiking. each tie should be carefully gauged as spiked and, as before indicated, the ties with the broadest faces being selected for the joints. in gauging ties it is very convenient to have measured off on the handles of the mauls in the hands of the forward spikers the distance from the outside of the rail to the end of the tie. this distance will then be gauged on the tie, when it will be lifted to the rail and securely spiked; the gauge is then used, and the loose rail held in place with the lining bar as previously indicated, loose gauge being given on curves, in accordance with directions of the engineer, the allowance for which is about / in. on a ° curve, up to about / in. on a ° curve. this widening of the gauge should begin on the tangent, back of the p.c., the full amount of excess over true gauge being reached by the time the p.c. is reached and continue all the way around the curve, running from the p.t. in the same manner as back of the p.c. the spikes should always be driven home straight and at right angles with the face of the ties. when the foreman in charge of the track-laying work sees a spiker, when the spike is nearly home, strike the spike head laterally, which is done to make it lie snugly to the rail, he should at once check such imperfect work and put the man who does it at other work. the foreman in charge of gang of spikers should be experienced in this branch of the work, and by weeding out imperfect workers, can soon get together a first-rate gang of spikers. but no trouble will be experienced from carelessly driven spikes, if the tie has the spike holes bored into it, before laying. this is considered good practice, but rather expensive. [illustration] for boring the holes quickly and accurately, a proper template should be made, by which the ties are marked for the borers, who should be provided with boring machines, by the use of which a hole, square with the face of the tie is bored. the boring machines should be so arranged as not to cut the hole beyond the required depth, which should be slightly less than the length of the spike. the diameter of the holes should be about - of an inch less than the thickness of the spike. this not only does away with the spike tearing its way through the timber and thus injuring its fiber to a great extent and causing it to be much more susceptible to rot, but it is said to increase the adhesion of the spike in hard wood ties at least per cent. but in order that the best results may be obtained, the spike should be flattened on either side of the sloping point, which will generally prevent it leaving the hole. the spikers should carefully avoid striking the rail with their mauls, as such carelessness often produces fracture, which sometimes causes the rail to break in two at such points, which is liable to produce derailment and serious accident. spike mauls should weigh not less than nine nor more than ten pounds, and should be on straight handles, not less than ft. long. after considerable use, the face of the maul will become somewhat rounded, and when this takes place it should be sent to the shop to be redressed. the last blow on the spike should be only sufficiently hard to cause its throat to fit snugly on the rail; a harder blow will often fracture the spike in such a manner as to cause the head in a short time to break off and leave the rail unsupported at that point. foremen should not allow a spike to be pulled, especially in frosty weather, until it has been first struck a light blow to break the rust and loosen its hold in the wood. the filling of old spike holes with wooden plugs is bad practice, for the reason that they will cause the spike in a short time to slip from its place; to fill the holes with sand is much better, and spikes driven in holes so filled will hold much more firmly. the best form of spike i have seen is the curved safety railroad spike; this spike takes in the tie a position which enables it to resist the thrust of the rail against it much more effectually than the ordinary spike can possibly do. i have seen in good condition, one of these curved spikes which was said to have been driven eight times. the cost of the curved safety spike is more than that of the ordinary spike, but it is better made, holds the track better, and, i believe, is worth more than the difference asked for it.--_j.a. hall, on construction and maintenance of track, before american society of civil engineers._ * * * * * the experiments at the annapolis proving grounds. the desperate war that has been waging between the gun and armor plate, ever since the period when protective plates were first applied to naval constructions, is familiar to all. in this conflict the advantage seems to lean toward the side of the gun, the power of penetration of which can be increased to almost indefinite limits, at least theoretically, while we quickly reach the extreme thicknesses of metal that can be practically employed for the protection of ships. so, in recent times, researches have been making upon the efficacy of armor plating, no longer in its exaggeration of thickness, but in the intrinsic quality of the metal of which it is composed. metallurgists have applied themselves to the work and have thus brought out various products, among which the plates called "compound," of messrs. cammell & co., have obtained a great notoriety. these plates, formed of a true plating of steel upon a bed of soft iron, have been much in vogue in the english navy, and seemed as if they were to be adopted about everywhere. the creusot works alone, of all competitors, were able to fight against the general infatuation. many comparative experiments had already demonstrated the superiority of the creusot "all steel" plates over the cammell plates, but messrs. schneider & go. were not willing to stop here, and finally produced the new nickel steel plate, which is by far superior to their steel plates. some comparative trials of these various armor plates have recently been made by a military commission of the united states at the annapolis proving grounds. three plates, one a cammell, the second a steel, and the third a nickel steel (the two last from creusot), were here submitted to firing, under absolutely identical conditions. our engravings show the proving grounds and the details of the arrangements adopted for backing the plates. of the three plates, the cammell was the thickest ( in.) the steel one was / in. in thickness, and the nickel steel / in. the last, therefore, was at a disadvantage with respect to the two others. the plates were arranged tangentially to an arc of a circle whose center was occupied by the pivot of the gun, and consequently at right angles with the latter. the piece employed was a in. gun, calibers in length. the distance of its muzzle from the plates attacked was ft. [illustration] the charge was lb. of brown prismatic powder. the projectile was a lb. holtzer shell. under these circumstances, the initial velocity was , ft. and the energy at the impact was , , ft. lb. a beginning was made by firing four shots at each plate in the bisectrix of the corners. then the in. gun was replaced by an in. one, throwing a lb. firth projectile, with an energy at the impact of , , ft. lb. each of the plates then received in its center a final blow from this projectile. our engraving represents the state of the plates after this last shot. [illustration: armored plate tests at annapolis] there is no need of being a great expert in questions of artillery to discover on what side the superiority is found, and to see that the cammell plate, almost entirely in fragments, is absolutely incapable of protection, while its two competitors are still in a state to resist. in one of our engravings may be seen, too, the state of the shells after each of the three shots. [illustration] the commission immediately and unanimously classified the three plates in the following order of superiority: ( ) nickel steel; ( ) all steel; ( ) compound. this triumph of french industry merits mention so much the more in that it was obtained in a series of experiments made in a foreign country--that is to say, under indisputable conditions of impartiality.-_l'illustration._ * * * * * high explosives in warfare.[ ] [footnote : a lecture delivered before the franklin institute, philadelphia, november , . from the _journal_ of the institute.] by commander f.m. barber, u.s.n. in commencing my paper this evening i desire to call your attention to the fact that i am dealing with a subject which, though not theoretical, is still hardly practical, for as a matter of fact high explosives cannot be said to have yet been regularly used in warfare, and i hope you will pardon me if in consequence my statements appear in some respects unsatisfactory and my theories unsound. my subject, however, is no more obscure than future naval warfare generally. all civilized nations are spending millions of money for fighting purposes directly in opposition to the higher feelings of the better class of their inhabitants. the political atmosphere of europe is the cause of this, but its consequence is the development of theoretical plans of ships which are no sooner commenced than the rapid march of mechanical, chemical, and electrical science shows them to be faulty in some particular feature, and others are laid down only to be superseded in their turn. none of these crafts are obsolete (to use the popular expression of the day). all are theoretically better than any which have stood the test of battle; but each excels its predecessor in some particular feature. the use of high explosives is the direct cause of the very latest transformations in marine architecture, and is destined to work still greater changes; but it will require a war between the most civilized nations of the world, and a long war, to either confirm or condemn the many theoretical machines and methods of destruction that modern science has produced. i say a war between the most civilized nations, since it is only they that can supply the educated intellect that is necessary to both attack and defense. under other circumstances false conclusions as to weapons and results are certain to be drawn. at the bombardment of alexandria, the english armorclads, with their rifled guns, were not nearly as efficient against the feeble chalk fortifications as our wooden ships would have been with smooth bore guns. on the other hand i saw on shore after the bombardment hundreds of torpedoes and miles of cable that the egyptians did not understand how to use. the french war with china was equally unsatisfactory from a military point of view. the chinese at foochow were annihilated because the french opened fire first, and the only shell that penetrated a french ironclad was filled with lamp black instead of powder. the national riots that we are accustomed to hear of in south america are likewise of little instructive value; they buy their weapons of more civilized people, but there is always something fatally defective about the tactics pursued in using them. it may be said in general terms that in these days of extreme power in fighting machines, the greater the efficiency the less the simplicity and the more knowledge required in the care of the weapons. when powder was merely powder the advice of the old adage to "trust in god and keep your powder dry" was ample to maintain the efficiency of the powder for all purposes; but nowadays if you keep your powder dry you will burst your gun, and if you keep your gun-cotton dry you are liable to blow up your ship. it is rather difficult to-day to define what high explosives are, in contradistinction to gunpowder. thirty years ago we could say that powder was a mechanical mixture and the others were chemical compounds; but of late years this difference has disappeared. the dynamical difference, however, still remains. gunpowder in its most efficient form is a slow-burning composition, which exerts a relatively low pressure and continues it for a long time and to a great distance. high explosives, on the contrary, in their most efficient form, are extremely quick-burning substances, which exert an enormous pressure within a limited radius. ordinary black gunpowder consists of a mechanical mixture of seventy-five per cent. of saltpeter, fifteen per cent of charcoal, and ten per cent. of sulphur. the most important of the high explosives are formed by the action of nitric acid upon organic substances or other hydrocarbons, the compound radical no being substituted for a portion of the hydrogen in the substance. the bodies thus formed are in a condition of unstable equilibrium; but if well made from good material, they become stable in their instability, very much like prince rupert's drops, those little glass pellets which endure almost any amount of rough usage; but once cracked, fly into infinitesimal fragments. the power exerted by these nitro-substitution products is due to the fact that they detonate, i.e., they are instantaneously converted into colorless gas at a very high temperature, and in addition they have almost no solid residue. nitro-glycerine actually leaves none at all, while gunpowder leaves sixty-eight per cent. the first departure in gunpowder from the old-time constituents of black powder just mentioned was for the purpose of obtaining less pressure and slower combustion than could be produced by mere granulating or caking. this was accomplished by using underburned charcoal, together with sugar and about one and one-half per cent. of water. this is the brown powder most generally used at present and with satisfactory results; but the abstraction of its moisture increases its rapidity of combustion to a dangerous degree, besides which the underburned charcoal is itself unstable. the next change demanded is smokelessness, and to accomplish it recourse is had to the high explosive field, mechanically mixing various substances with them to reduce and regulate their rapidity of action. just now some form of gun-cotton is most in use mixed with nitrate of ammonia, camphor and other articles. the tendency of these mixtures is to absorb moisture, and the gun-cotton in them to decompose, and there is no smokeless powder which can to-day be considered successful. such a powder, however, will undoubtedly be an accomplished fact in the near future. military men seem to be a great deal at variance as to its value in the field, but there can be no doubt of its value for naval purposes; it is a necessity forced upon us by the development of torpedo warfare. first came the simple torpedo, at the end of an ordinary boat's spar. then came the special torpedo boat with its great speed, then the revolving cannon and rapid-fire gun to meet the torpedo boat. at present the possible rapidity of fire is much greater than can be utilized, on account of the smoke; hence the necessity of smokeless powder. smokelessness is, however, principally a martial demand that has been made upon the science of explosives and has attracted public attention on that account. the commercial demands for various other properties have been much greater than the military, and between gunpowder near one end of the line in point of power and nitro-glycerine near the other, there are now over different explosives manufactured, and most of these have been invented within the last twenty years. the simplest application of high explosives in warfare is in connection with torpedoes, since within the same bulk a much more efficient substance can be obtained than gunpowder, and with reasonable care there is very little danger of premature explosions by reason of accidental shocks. torpedoes were made by the chinese many years ago, they were tried in our war of independence, and also by the russians during the crimean war; but the first practical and successful use of them as a recognized weapon was during our war of secession, when thirty-seven vessels were either sunk or seriously injured by them. gunpowder was used in these torpedoes, though it is stated that attempts were made to use other substances without success. since that time all maritime nations have made a close study of the subject and have adopted various high explosives, according to the results of their experiments. in general terms it may be stated that explosive chemical compounds have been found more suitable than explosive mixtures, because of the uniformity of direction in which they exert their pressure, and from the fact that water does not injure them. mixtures may be very powerful, but they are erratic and require tight cases. in the united states we use dynamite for harbor mines. it is composed of seventy-five per cent. nitro-glycerine and twenty-five per cent. silica; but blasting gelatine and forcite gelatine will probably be adopted, when they can be satisfactorily manufactured here, as they are more powerful. the former is composed of ninety-two per cent. of nitro-glycerine and eight per cent. of gun-cotton, and the latter of ninety-five per cent. of nitro-gelatine and five per cent. unnitrated cellulose. for naval use we have adopted gun-cotton as being the most convenient. in europe gun-cotton is generally used for both fixed mines and movable torpedoes; russia, austria, and italy use blasting gelatine also. in actual warfare but little experience has been had. two peruvian vessels were sunk by dynamite in the chili-peruvian war, one turk by means of gun-cotton during the turco-russian war of , and two chinese by gun-cotton in the franco-chinese war of . in making experiments to determine the relative strength of the different explosives under water, very curious and puzzling results have been obtained. nitro-glycerine being the simplest and most complete in its chemical decomposition, and apparently the most powerful in air, it was natural to suppose that it would be the same in submarine work, but it was found by gen. abbot, at willets point, after repeated experiments, as shown in his report of , that it was not so powerful in its effect by twenty per cent. as dynamite no. , although the dynamite contained twenty-five per cent. of an absolutely inert substance. his idea was that it was too quick in its action, and, since water is slightly compressible, a minute fraction of time is required in the development of the full force of the explosive. gen. abbot's results for intensity of action per unit of weight of the most important substances is as follows: blasting gelatine........................... forcite " ........................... dynamite no. .............................. gun-cotton, wet............................. nitro-glycerine............................. gunpowder.............................. to col. bucknill, of the royal engineers, in his publication of , gives the following: blasting gelatine........................... forcite " ........................... dynamite no. .............................. gun-cotton, dry............................. " " ............................. gunpowder................................... in both tables dynamite no. is assumed as the standard of comparison. col. bucknill states that his gun-cotton results differ from gen. abbot's, because he experimented with much larger quantities, viz., -pound charges. gen. abbot's experiments led him to believe that an instantaneous mean pressure of , pounds per square inch would give a fatal blow to the double bottom of a modern armorclad, and he developed a formula which gives this blow with blasting gelatine at the following distances under water, viz.: pounds. at feet.................................. " " .................................. " " .................................. " " .................................. " " .................................. col. bucknill's experiments caused him to believe that a pressure of , pounds per square inch is required, and his formula, which is somewhat different from abbot's, gives widely different results at close quarters, but they approach each other as the distance increases. his results are as follows: pounds. at feet................................ / " " ................................ " " ................................ " " ................................ " " ................................ regarding the comparative effects of gunpowder and the high explosives, i think gen. abbot's estimate of a varying value for powder is more admissible than the fixed value assigned by col. bucknill. gunpowder gives a push and detonating compounds a shock; as the quantities increase, the push reaches farther than the shock. according to gen. abbot, pounds of dynamite no. will have a destructive horizontal range of . feet, while the same amount of gunpowder will only have a range of . feet. five hundred pounds of dynamite, however, will have a horizontal range of feet, and pounds of gunpowder will have . feet; the ratio has diminished from five to two. whether , pounds or , pounds per square inch is necessary to crush the bottom of an armorclad will depend largely upon how far apart the frames of the ship are spaced and what other bracing is supplied, as well as many local circumstances. it is difficult to judge exactly of these matters. some four years ago the italian government adopted treble bottoms for their heaviest ships as a result of experiments with seventy-five pounds of gun-cotton (the charge of an ordinary whitehead locomotive torpedo) against a caisson which was a _fac-simile_ of a portion of the proposed ships. only two of the bottoms were broken through, and when the space between the two inner bottoms was filled with coal, only the outer bottom was broken. according to the formulæ of either abbot or bucknill, there should have been a local pressure of at least , pounds per square inch on the outer skin, and yet judicious interior arrangements rendered it harmless to the target. it would not, however, be safe to conclude that the torpedo was thus vanquished; the immediate result was simply to create a demand for larger locomotive torpedoes for local application, and but little light was thrown upon the results which might be anticipated from a large mine at a greater distance, whose radius of explosive effect would embrace a larger portion of the ship, and especially if the ship were nearly over the torpedo. the local effect of a detonation is different from the transmitted shock. experiments in england have shown that pounds of gun-cotton at forty feet below any ship will sink her, and at a horizontal distance of feet, damage to the interior pipes and machinery is to be expected. the fact that the high explosives are so much heavier than gunpowder has an important bearing on the size of the containing case. their sp. gr. is as follows: nitro-glycerine............................ . blasting gelatine.......................... . forcite " .......................... . dynamite no. ............................. . wet gun-cotton............................. . dry " ............................. . gunpowder.................................. . their relative efficiency under water per cubic foot, according to bucknill, is as follows: blasting gelatine.......................... . forcite " .......................... . dynamite no. ............................. . dry gun-cotton............................. . wet " ............................. . gunpowder.................................. . the wet gun-cotton has twenty-five per cent. of added water. mines for harbor defense are of two kinds--buoyant and ground. the buoyant are usually spherical, and contain from to pounds of explosive. they bring the charge near to the ship's bottom, but are difficult to manage in a tideway, and can be easily found by dragging. the ground mines can be made of any size and are not easily found by dragging, but are of little value in very deep water. they are either cylindrical or hemispherical in shape, and contain from to , pounds of explosive in from thirty to eighty feet of water. mines of any kind are exceedingly difficult to render efficient when the water is over feet deep. on account of the tendency of all high explosives to detonate by influence or sympathy, and the liability of the cases to collapse by great exterior pressure, harbor mines are separated a certain distance, according as they are buoyant or ground, and according to the nature of the explosive. five hundred pounds buoyant gun-cotton mines require feet spacing. five hundred pounds buoyant blasting gelatine mines require feet spacing. six hundred pounds ground gun-cotton mines require feet spacing. six hundred pounds ground blasting gelatine mines require feet spacing. of torpedoes, other than those described, we have several modern varieties; submarine projectiles, submarine rockets, automobile and controllable locomotive torpedoes. the first two varieties, though feasible, are not developed and have not yet advanced beyond the experimental stage. of the automobile, we have the whitehead, swartzkopf and howell. the first two are propelled by means of compressed air and an engine; the last by the stored-up energy of a heavy fly-wheel. generally speaking, they are cigar-shaped crafts, from to feet long and to inches in diameter, capable of carrying from to pounds of explosive at a rate of to knots for yards, at any depth at which they may be set. of the controllable locomotive torpedoes, the three representative types are the patrick, sims and brennan. they are in general terms cigar boats, about feet long and feet in diameter, carrying charges of pounds of explosive. the patrick and sims are maintained at a constant depth under water by means of a float. the brennan has diving rudders like a whitehead or a howell. the patrick is driven by means of carbonic acid gas through an engine, and is controlled by an electric wire from shore. the sims is driven by electricity from a dynamo on shore through a cable to an electric engine in the torpedo. the brennan is driven and controlled by means of two fine steel wires wound on reels in the torpedo, the reels being geared to the propeller shafts. the wires are led to corresponding reels on shore, and these are rapidly revolved by means of an engine. a brake on each shore reel controls the torpedo. the speed of all these torpedoes is about knots, and their effective range one mile. a whitehead was successfully used in the turco-russian war of . the turkish vessel previously mentioned was sunk by one. blasting gelatine, dynamite and gun-cotton are capable of many applications to engineering purposes on shore in time of war, and in most cases they are better than powder. they received the serious attention of french engineers during the siege of paris, and were employed in the various sorties which were made from the city, in throwing down walls, bursting guns, etc. an explosive for such purposes, and indeed for most military uses, should satisfy the following conditions: ( ) very shattering in its effects. ( ) insensible to shocks of projectiles. ( ) plastic. ( ) easy and safe to manipulate. ( ) easy to insert a fuse. ( ) great stability at all natural temperatures and when used in wet localities. neither blasting gelatine, dynamite nor gun-cotton fulfills all these conditions; but they satisfy many of them and are more powerful than other substances. for the destruction of walls, trees, rails, bridges, etc., it is simply necessary to attach to them small bags of explosive, which are ignited by means of blasters' fuse and a cap of fulminate of mercury, or by an electric fuse. we now come to the application of high explosives to warfare in the shape of bursting charges for shells. this is the latest phase of the problem, and it is undoubtedly fraught with the most important consequences to both attack and defense. difficult as it has been to obtain an exact estimate of the force of different explosives under water, the problem is far greater out of the water and under the ordinary conditions of shell fire; the principal obstacle being in the fact that it is physically impossible to control the force of large quantities in order to measure it, and small quantities give irregular results. theoretically, the matter has been accomplished by berthelot, the head of the french government "commission of explosives," by calculating the volume of gas produced, heat developed, etc.; and this method is excellent for obtaining a fair idea of the specific pressure of any new explosive that may be brought forward, and determining whether it is worth while to investigate it further; but the explosives differ so much from each other in point of sensitiveness, weight, physical condition, velocity of explosive wave, influence of temperature and humidity, that we cannot determine from mere theoretical considerations all that we would like to know. various methods of arriving at comparative values have been tried, but the figures are very variable, as will be seen by the following tables. berthelot's commission, some ten years ago, exploded ten to thirty grammes of each in pound blocks of lead and measured the increased size of the hole thus made. the relative result was: no. dynamite . dry gun-cotton . nitro-glycerine . powder blew out and could not be measured. mr. r.c. williams, at the boston institute of technology, in the winter of and , tried the same method, but used six grammes in forty-five pound blocks of lead. he obtained a relative result of-- no. dynamite . dry gun-cotton . nitro-glycerine . explosive gelatine . forcite gelatine . warm nitro-glycerine . gunpowder . the powder gave great trouble in this case, also, by blowing out. m. chalon, a french engineer, obtained some years ago, with a small mortar, firing a projectile of thirty kilos and using a charge of ten grammes of each explosives, the following ranges: meters. blasting powder . no. dynamite . forcite of per cent. n.g. . blasting gelatine . roux and sarran obtained by experiments in bursting small bomb shells the following comparative strengths of ranges: powder . gun-cotton . nitro-glycerine . in actual blasting work the results vary altogether with the nature of the material encountered, and with the result that is desired to be accomplished, viz., throwing out, shattering, or mere displacement. chalon gives for quarrying: powder dynamite no. , containing per cent. nitro-glycerine for open blasting: dynamite no. , containing per cent. n.g. . dynamite no. , containing per cent. n.g. . blasting gelatine . for tunneling: dynamite no. , containing per cent. n.g. dynamite no. , containing per cent. n.g. explosive gelatine finally berthelot's theoretical calculations give a specific pressure of-- powder dynamite gun-cotton nitro-glycerine blasting gelatine it will be observed that the practical results vary largely from the theoretical values, but they seem to indicate that gun-cotton and no. dynamite are very nearly equal to each other, and that in the nitro-glycerine compounds, except where gun-cotton is added, the force appears to be nearly in proportion to the nitro-glycerine contained. from the foregoing it seems fair to estimate roughly the values of bursting charges of shells as follows: powder gun-cotton and dynamite to nitro-glycerine to blasting gelatine to attention has been turned in europe for more than thirty years toward firing high explosives in shells; but it is only within very late years that results have been reached which are claimed as satisfactory, and it is exceedingly difficult to obtain reliable accounts even of these. dynamite was fired in sweden in in small quantities, and a few years later it was fired in france. but two difficulties soon presented themselves. if the quantity of nitro-glycerine in dynamite was small, it could be fired in ordinary shells, but the effect was no better than with gunpowder. if the dynamite was stronger in nitro-glycerine, it took but a small quantity to burst the gun. as early as , dry gun-cotton was safely fired in shells in small quantities, but when a sufficient quantity to fill the shell cavity was used, the gun burst. some few years ago it was found that if the gun-cotton was either wet or soaked in paraffin, it could be fired with safety from powder guns in ordinary shells, provided the quantity was small in proportion to the total weight of the shell--say five or six per cent. but a new difficulty arises from the fact that it breaks the shell up into very small pieces, and it is an unsettled question among artillerists whether more damage is done to an enemy by breaking a shell into comparatively large pieces and dispersing them a long distance with a bursting charge of powder, which has a propulsive force, or by breaking it with a detonating compound into fine pieces, which are not driven nearly so far. when used against troops there is also the objection to the high explosive shell that it makes scarcely any smoke in bursting, and smoke at this point is useful to the artillerist in rectifying his aim. in the matter of shells for piercing armor, however, there are no two opinions regarding the nature of the bursting charge. to pierce modern armor at all a shell must be made of forged steel, so thick that the capacity of the cavity for the bursting charge is reduced to one-fourth or one-fifth of what it is in the common shell; the result is that a charge of powder is frequently not powerful enough to burst the shell at all; it simply blows the plug out of the filling hole in the rear. in addition it is found that in passing through armor, the heat generated is so great that the powder is prematurely ignited. if then we can fill the small cavity in the shell with an explosive which will not ignite prematurely, and yet will burst the shell properly after it has passed through the armor, the problem will be solved. wet or paraffined gun-cotton can be made sluggish enough to satisfy the first condition; but at present the difficulty is to make it explode at all. the more sluggish the gun-cotton, the more powerful must be the fuse exploders to detonate it, and such exploders are themselves liable to premature ignition in passing through the armor. the italians and germans claim to have accomplished the desired result up to a thickness of five inches of armor; gun-cotton and fuse both working well. but the english authorities say that no one has yet accomplished it. the austrians claim to have succeeded in this direction within the last year with a new explosive called ecrastite (supposed to be blasting gelatine combined with sulphate or hydrochlorate of ammonia, and claimed to be one and one-half times as powerful as dynamite). with a gun of . inches caliber and an armor-piercing shell weighing . pounds, containing a bursting charge of . pounds of ecrastite, they are said to have perforated two plates four inches thick, and entered a third four-inch plate where the shell exploded. there is a weak point in this account in the fact that the powder capacity of the shell is said to be . pounds. this amount is approximately correct, judging from our own eight-inch armor-piercing shell, but if this is true, there could not have been more than nine pounds of ecrastite in the shell instead of sixteen, or else there is an exceedingly small proportion of blasting gelatine in ecrastite, and if that is the case it is not one and one-half times as powerful as dynamite. if it is weak stuff, it is probably insensitive, and even if it were strong, one swallow does not make a summer. the english fired quantities of blasting gelatine from a two-inch nordenfeldt gun in , but when they tried it in a seven-inch gun, in , they burst the gun at once. i have only analyzed this austrian case, because the statement is taken from this year's annual report of the office of naval intelligence, which is an excellent authority, and to illustrate the fact that of the thousands of accounts, which we see in foreign and domestic newspapers, concerning the successful use of high explosives in shells, fully ninety per cent. are totally unreliable. in many cases they are in the nature of a prospectus from the inventors of explosives or methods of firing, who are aware of the fact that it is almost impossible to dispute any statements that they may choose to make regarding the power of their new compounds, and thinking, as most of them do, that power alone is required. referring to the qualities that i have previously cited as being required in a high explosive for military purposes, it is sooner or later found that nearly all the novelties proposed lack some of the essentials and soon disappear from the advertising world only to be succeeded by others. the most common defect is lack of keeping qualities. they will either absorb moisture or will evaporate; or further chemical action will go on among the constituents, making them dangerously sensitive or completely inert, or they will separate mechanically according to their specific gravities. for further clearness on the subject of the shell charges which have so far been discussed, the following table is added of weight and sizes of shells for united states naval guns, with their bursting charges of powder: -inch com. cast steel shell / to cal. long, wt. lb., charge lb. " " " " " " / lb. " " " " " " " " " " " " " " armor-piercing forged steel shell. -inch, calibers long, weight lb, charge / lb. " " " " " " " " " / " " " " " " the chief efficiency of small quantities of high explosives having reduced itself to the case of armor-piercing projectiles, it next became evident that there was an entirely new field for high explosives into which powder had entered but little, and this was the introduction of huge torpedo shells, which did nor rely for their efficiency upon the dispersion of the pieces of the shell, but upon the devastating force of the bursting charge itself upon everything within the radius of its explosive effect. it is in this field that we may look for the most remarkable results, and it is here that the absolute power of the explosive thrown is of the utmost importance, provided that it can be safely used. attention was at once turned in europe to the manufacture of large projectiles with great capacity for bursting charges, and it has resulted in the production of a class of shells / to calibers long, with walls only . of an inch thick. (if they are made thinner, they will swell and jam in the gun when fired.) these shells are used in long guns up to and / inches caliber, and in mortars up to . inches. they are made from disks of steel, to feet in diameter and inch thick, and are forced into shape by hydraulic presses. the base is usually screwed in, but some of the german shell are made in two halves which screw together. the italians were the first in this new field of investigation, but the germans soon followed, and after trying various materials were at length reasonably successful with gun-cotton soaked in paraffin. their . inch mortar shells of calibers contain pounds; those of calibers contain pounds; and the . inch mortar shells of calibers contain pounds. the projectile velocity used with the mortars is about f.s. the effect of these shells against ordinary masonry and earth fortifications is very great. the charge of forty-two pounds has broken through a masonry vault of three feet four inches thick, covered with two feet eight inches of cement and with three to five feet of earth over all. the shell containing fifty-seven pounds, at a range of two and one-half miles, broke through a similar vault covered with ten feet of earth; but with seventeen feet of earth the vault resisted. in , experiments at kummersdorf showed that a shell containing the fifty-seven pound charge would excavate in sand a crater sixteen feet in diameter and eight feet deep, with a capacity of twenty-two cubic yards. the italians have had similar experiences; but it is notable that in both germany and italy several guns and mortars have burst. the velocity in the guns is not believed to exceed , to , f.s., and it is not thought that the quantity of gun-cotton is as great in the gun shells as in the mortars. i have lately been informed on good authority that the use of gun-cotton shells has been abandoned in the german navy as too dangerous. the french, in their investigations in this field, found gun-cotton too inconvenient, and decided upon melenite. this substance has probably attracted more attention in the military world than all others combined, on account of the fabulous qualities that have been ascribed to it. its composition was for a long time entirely a secret; but it is now thought to consist principally of picric acid, which is formed by the action of nitric acid upon phenol or phenyillic alcohol, a constituent of coal tar. the actual nature of melenite is not positively known, as the french government, after buying it from the inventor, turpin, are said to have added other articles and improved it. this is probable, since french experiments in firing against a partially armored vessel, the bellequense, developed an enormous destructive effect, while the english, who afterward bought it, conducted similar experiments against the resistance, and obtained no better results than with powder. the proof that the bellequense experiments were deemed of great value by the french lies in the fact that they immediately laid down a frigate--dupuy de lome--in which four-inch armor is used, not only on the side, but about the gun stations, to protect the men; this thickness having been found sufficient to keep out melenite shell. in most armorclads, the armor is very heavy about the vitals, but the guns are frequently much exposed. the best authenticated composition for melenite consists of picric acid, gun cotton and gum arabic, and lately it is stated that the french have added cresilite to it. cresilite is another product of coal tar. melenite is normally only three times as strong as gunpowder; but it is said to owe its destructive qualities in shells to the powerful character of the exploder which ignites it. it has been known for some years that all explosives (including gunpowder) are capable of two orders of explosion according as they are merely ignited or excited by a weak fuse or as they are powerfully shocked by a more vigorous excitant. fulminate of mercury has been found most serviceable for the latter purpose. with melenite the french have reproduced all the results that the germans have effected with gun-cotton and have found that a shell containing pounds of it will penetrate nearly ten feet of solid cement, but will not penetrate armored turrets six to eight inches thick. the french claim that melenite has an advantage over gun-cotton in not being so dangerous to handle and being insensible to shock or friction, and they have obtained a velocity of , f.s. with the inch mortar and claim to have obtained , f.s. in long guns up to inch caliber. however this may be, they are known to have had severe accidents at the manufactory at belfort and at least one inch gun was burst at the bellequense experiments in firing a sixty-six pound shell containing twenty-eight pounds of melenite. the french are said to have large quantities of melenite shells in store, but they are not issued to service. probably one reason why we have so many conflicting yet positive accounts of great successes in europe with torpedo shells is because each nation wishes its neighbors to think that it is prepared for all eventualities, and they are obliged to keep on hand large quantities of some explosive, whether they have confidence in it or not. fortunately we are not so situated, but singularly enough what we have done in the field of high explosive projection has been accomplished by private enterprise, and we have attacked the problem at exactly the opposite point from which european nations have undertaken it. while they have assumed that the powder gun with its powerful and relatively irregular pressures was a necessity and have endeavored to modify the explosive to suit it, we have taken the explosive as we have found it, and have adapted the gun to the explosive. at present the prominent weapon in this new field is the pneumatic gun, but it is obvious that steam, carbonic acid gas, ammonia or any other moderate and regulatable pressure can be used as well as compressed air; it is merely a question of mechanical convenience. in throwing small quantities of certain high explosives, powder guns can be used satisfactorily, but when large quantities are required, the mechanical system of guns possess numerous advantages. all the high explosives are subject to premature detonation by shock; each of them is supposed to have its own peculiar shock to which it is sensitive; but what this shock may be is at present unknown. we do know, however, that premature explosions in guns are more liable to occur when the charge in the shell is large than when it is small. this is due to the fact that when the gun is fired, the inertia of the charge in the shell is overcome by a pressure proportional to the mass and acceleration, which pressure is communicated to the shell charge by the rear surface of the cavity, and the pressure per unit of mass will vary inversely as this surface. if, then, the quantity of explosive in the shell forms a large proportion of the total weight of the shell, we approach in powder guns a condition of shock to it which is always dangerous and frequently fatal. the pressure behind the projectile varies from twelve to fifteen tons per square inch, but it is liable to rise to seventeen and eighteen tons, and in the present state of the manufacture of gunpowder we cannot in ordinary guns regulate it nearer than that. it is not a matter of so much importance so far as the guns are concerned, when using ordinary projectiles, as the gun will endure a pressure of from twenty-five to thirty tons per square inch; but with high explosives in the shell it is a vitally serious matter. from all i can learn regarding european practice, it appears that not only are the explosives made sluggish, but the quantity seldom exceeds thirty per cent. of the weight of the shell, and the velocities, notwithstanding, are kept very low. in the pneumatic gun the velocity is low also, but so is the pressure in the gun. the pressure in the firing reservoir is kept at the relatively low figure of , pounds per square inch or less, and the air is admitted to the chamber of the gun by a balance valve which cuts off just the quantity of air (within a very few pounds) that is required to make the shot. the gun is long, and advantage is taken of the expansion of the air. in no case can the pressure rise in the gun beyond that in the reservoir. up to the present time there have been no accidents in using the most powerful explosives in their natural state, and in quantities over fifty per cent. of the weight of the projectile. i have seen projectiles weighing pounds, and containing pounds of explosives ( pounds of the blasting gelatine and pounds of no. dynamite) thrown nearly a mile and exploded after disappearing under water. according to gen. abbot's formula such a projectile would have sunk any armorclad floating within forty-seven feet of where it struck. apparently there is no limit to the percentage of explosive that can be placed in the shell except the mechanical one of having the walls thick enough to prevent being crushed by the shock of discharge. in the large projectiles a transverse diaphragm is introduced to strengthen the walls and to subdivide the charge. the development of the pneumatic gun has been attended with some other important discoveries, which may be of interest. it is well known that mortar fire is very inaccurate, except at fixed long distances, in consequence of the high angle, the slowness of flight of the projectile, the variability of the powder pressure, and the inability to change the elevation and the charge of powder rapidly. in the pneumatic gun, the complete control of the pressure remedies the most important of the mortar's defects and makes the fire accurate from long ranges down to within a few yards of the gun. it is obvious that the pressure can be usefully controlled in two ways: ( ) by keeping the elevation of the gun fixed and using a valve that can be set to cut off any quantity of air, according to the range desired; ( ) by keeping the pressure in the reservoir constant, and using a valve which will cut off the same quantity of air every time, changing the elevation of the gun according to the distance. another important discovery consists in the application of subcalibered projectiles for obtaining increased range. the gun is smooth-bored and a full-sized projectile is a cylinder with hemispherical ends, to the rear of which is attached a shaft having metal vanes placed at an angle, which causes the projectile to revolve round its longer axis during flight. a subcalibered projectile, however, being of less diameter than the bore of the gun, has the vanes on its exterior, and is held in the axis of the gun by means of gas checks which drop off as the projectile leaves the muzzle. the shock to the explosive is, of course, greater than in the full-sized projectile, but the increase can be calculated, and so far a dangerous limit has not been reached. from the fifteen-inch gun with a pressure of , pounds per square inch and a velocity of about f.s., a range of , yards has been obtained at an elevation of ° , with a ten-inch subcalibered projectile, about eight calibers long and weighing pounds. this projectile will contain pounds of blasting gelatine. with improved full-sized projectiles weighing , pounds, a range of , yards will doubtless be obtained. at elevations below ° these long projectiles are liable to ricochet, and what is now wanted is a projectile which will stay under water at all angles of fall and will run parallel to the surface like a locomotive torpedo. such a projectile has yet to be invented; but i have seen a linked shell, which has been experimented with from a nine-inch powder gun, that partially meets this condition. it is made of several sections united by means of rope or electric wire in lengths of to feet. when fired all sections remain together for some distance; the rear section then first begins to separate; then the next, and so on. it is primarily intended to envelop an enemy's vessel, and to remedy the present uncertainty of elevation in a gun mounted in a pitching boat; but it is found that when it strikes the water in its lengthened out condition, it will neither dive nor ricochet, but will continue for some distance just under the surface until all momentum is lost, when it will sink. this projectile is at present crude, and has never been tried loaded, but it will probably be developed into something useful in time. i have confined my remarks in the foregoing discussion principally to such methods of using high explosives in shells as have proved themselves successful beyond an experimental degree, and practically they reduce themselves to two, viz., using a sluggish explosive in small quantities from an ordinary powder gun, and using any explosive from a pneumatic or other mechanical gun. naturally, the success of the latter method will soon induce the manufacture of powders having an abnormally low maximum pressure. there is undoubtedly a field for the use of such powders in connection with an air space in the gun to still further regulate the pressure; but nothing of this sort has yet been attempted. many methods of padding the shell have been devised for reducing the shock in powder guns, but the variability of the powder pressure is too great to have yet rendered any such method successful. a method was patented by gruson in germany of filling a shell with the two harmless constituents of an explosive and having them unite and explode by means of a fulminate fuse on striking an object. he used for the constituents nitric acid and dinitro-benzine, and was quite successful; but the system has not met with favor, on account of the inconvenience. the explosive was about four times as powerful as gunpowder. that the advantage of using the most powerful explosives is a real one can be easily shown. the eight inch pneumatic gun in new york harbor, with a projectile containing fifty pounds of blasting gelatine and five pounds of dynamite, easily sunk a schooner at , yards range from the torpedo effect of the shell falling alongside it. this same shell, if filled with gunpowder, would have contained but twenty-five pounds, and have had but one-ninth the power. the principal european nations are now building armored turrets sunk in enormous masses of cement, as a result of their experiences with gun-cotton and melenite. the fifteen inch pneumatic projectile, which i described as being capable of sinking an armorclad at forty-seven feet from where it struck, would have been capable of penetrating fifty feet of cement had it struck upon a fortification. it was not only a much larger quantity of high explosive than europeans have experimented with, but the explosive itself is probably more than twice as strong as their gun-cotton and five or six times as strong as their melenite. in the plans of gen. brialmont, one of the most eminent of european engineers, he allows in his fortifications about ten feet of cement over casements, magazines, etc. it is evident that this is insufficient for dynamite shells such as i have described. at fort wagner, a sand work built during our war, gen. gillmore estimated that he threw one pound of metal for every . pounds of sand removed. he fired over , pounds of metal, and one night's work would have repaired the damage. the new fifteen inch pneumatic shell will contain pounds of blasting gelatine, and judging from the german experiments at kummsdorf, which i have cited, one of these fifteen inch shells would throw out a prodigious quantity of sand; either pounds to one of shell, or , pounds to one of shell, according as the estimate of gen. abbot or of capt. zalinski is used. the former considers that the radius of destructive effect increases as the square root of the charge; the latter that the area of destructive effect for this kind of work is directly proportional to the charge. the effect of the high explosives upon horizontal armor is very great; but we have yet to learn how to make it shatter vertical armor. no fact about high explosives is more curious than this, and there is no theory to account for it satisfactorily. as previously stated, the french have found that four inches of vertical armor is ample to keep out the largest melenite shells, and experiments at annapolis, in , showed that masses of dynamite no. , weighing from seventy-five to pounds, could be detonated with impunity when hung against a vertical target composed of a dozen one inch iron plates bolted together. in conclusion, i may say that in this country we are prone to think that the perfection of the methods of throwing high explosives in shell is vastly in favor of an unprotected nation like ourselves, because we could easily make it very uncomfortable for any vessels that might attempt to bombard our sea coast cities. this is true as far as it goes, but unfortunately the use of high explosives will not stop there. i lately had explained to me the details of a system which is certainly not impossible for damaging new york from the sea by means of dynamite balloons. the inventor simply proposed to take advantage of the sea breeze which blows toward new york every summer's afternoon and evening. without ever coming in sight of land, he could locate his vessel in such a position that his balloons would float directly over the city and let fall a ton or two of dynamite by means of a clock work attachment. the inventor had all the minor details very plausibly worked out, such as locating by means of pilot balloons the air currents at the proper height for the large balloons, automatic arrangements for keeping the balloon at the proper height after it was let go from the vessel, and so on. his scheme is nothing but the idea of the drifting or current torpedo, which was so popular during our war, transferred to the upper air. an automatic flying machine would be one step farther than this inventor's idea, and would be an exact parallel in the air to the much dreaded locomotive water torpedo of to-day. there seems to be no limit to the possibilities of high explosives when intelligently applied to the warfare of the future, and the advantage will always be on the side of the nation that is best prepared to use them. * * * * * the manufacture and use of plaster of paris. it has long been a familiar fact that gypsum yields on baking a material which possesses the power of setting with water to a firm mass, this setting being accomplished much more quickly than is the case with mortar. the explanation of the setting of plaster was first given by lavoisier, who pointed out that gypsum is an hydrated salt, and that the set plaster is in fact gypsum reformed, the change brought about by baking being merely loss of water of crystallization. the beds of gypsum of most importance both formerly and at the present time in the plaster manufacture occur in the neighborhood of paris in the lower tertiary formation. different beds differ ( ) in respect of character and quantity of admixed materials and ( ) in the structure of the gypsum itself. with regard to the first point, some deposits contain a notable proportion of carbonate of lime, a fact which under certain circumstances may considerably influence the character of the plaster. in the matter of structure two principal varieties occur ( ) granular and ( ) fibrous. further, hardness of the granular kind varies considerably. these differences of structure in the original material appear to exercise an influence on the properties of the plaster. thus according to payen the plaster formed from the granular variety sets more gradually than that derived from the fibrous, and forms a denser mass. the softer kinds of the granular gypsum are those principally used in the production of plaster for the moulds of potteries. in the old fashioned process which is still employed for making the common kinds of plaster, the material is exposed to the direct action of flame. large lumps are placed in the lower part of the furnace, above them smaller lumps, and, after the heating has been carried on for some time, finely divided material is filled in at the top. the outer portion of the larger lumps is always overburnt, and in the upper part of the furnace the presence of shining crystalline particles generally indicates the fact that some gypsum has remained unchanged. provided that the amount of unburnt and overburnt material does not exceed about per cent. of the total, the plaster is suitable for many applications. it was early observed that set plaster could be revivified by a second baking, but attempts in this direction were not uniformly successful, it being found that the dehydrated substance in some cases refused to set with water. it behaved in fact similarly to the natural anhydrous calcium sulphate which is unaffected by water. these failures were found to be due to the employment of too high a temperature, and such plaster was termed _dead burnt_. although this fact was ascertained long ago, yet ignorance of what had already been done has probably been the cause of many disappointments in attempts at revivification which have been made from time to time by persons unacquainted with the history of the subject. the view generally adopted with regard to the theory of these processes is that plaster consists of anhydrous calcium sulphate, caso , in a condition probably amorphous, different from that of natural crystallized caso , known to mineralogists under the name of anhydrite. by the influence of a high temperature it appears probable that a molecular change is gradually induced with production of a crystalline structure, and probably an increase of specific gravity, resulting in the artificial reproduction of the mineral anhydrite. no determination appears to have been published of the specific gravity of plaster prepared by complete baking at a low temperature. the theory is, however, confirmed by the results obtained by workers on the subject of mineralogical synthesis, who have shown that the material which has been produced at high temperatures has the specific gravity and other physical properties of the mineral anhydrite. it was formerly supposed that plaster prepared by baking at a temperature above degrees loses completely its power of setting. later observations, however, as those of landrin, negative this view. between degrees and degrees landrin obtained plasters setting almost instantaneously when mixed with a small amount of water. when the temperature employed approached degrees, the set plaster was softer, but the setting still took place quickly. these observations appear to show that the change to anhydrite is a very gradual process at temperatures below a red heat. reference has been made to the differences in ( ) time of setting of plaster and ( ) in hardness of the resulting material. both of these properties are affected by the mode of baking. the hardest material is frequently obtained from the quick-setting plasters, but for certain purposes this rapidity in setting is of great practical inconvenience. thus the moulder in pottery work must have leisure to fill in every detail of a design often complicated and intricate before the material with which he is working becomes intractable. thus for many of the more refined purposes to which plaster is applied, extreme hardness in the set plaster is of less vital importance than a convenient period of setting. on the other hand, plasters which set very slowly give as a rule too soft a material, as well as being inconvenient in use. plasters which hit off the happy medium are alone suitable for the work of the potter. the finer varieties of plaster prepared especially for use in potteries are obtained by a treatment which differs in many respects from that described above for the commoner kinds. in the first place, the direct contact of fuel or even flame is avoided, since this reduces some of the sulphate to sulphide of calcium, the presence of which is in many respects objectionable. secondly, it is necessary that there should be a better control over the temperature, since, as has been seen, if the heating be carried too far the plaster, if not partially dead burnt, will set too quickly for the particular purpose to which it is to be put. the arrangement employed in france is known as the _four a boulanger_, or baker's furnace. the temperature attained in the furnace itself never exceeds low redness. the material preferred is the softer kind of the granular variety of gypsum. this is put in in pieces of about / inches in thickness. after the baking several lumps are broken up and examined to see that there are no shining crystalline particles, which would indicate that some of the gypsum had remained unchanged. before use the plaster is ground very fine. this point is of considerable practical importance. the consistency attained should be such that the material may be rubbed between the finger and thumb without any feeling of grittiness. should there be particles of a size to be characterized as "grit," these will after use appear at the surface of the mould, with the result that the mould will have to be abandoned long before it is really worn out, i.e., before the details have lost their sharpness. it is manifestly of considerable practical importance to understand the conditions which determine the time of the setting up of plaster. according to payen, the rapidity of setting, provided the plaster has dehydrated at a temperature sufficiently low, depends entirely on the structure of gypsum employed. thus, according to him, the fibrous kinds gives a plaster setting almost instantaneously. the water, he says, penetrates the material freely, setting takes places almost simultaneously throughout the mass. the hydration of each particle is accompanied by an expansion, and under the conditions specified, this expansion being unresisted takes place to the maximum extent, with the result of leaving cavities between the crystals, and producing a set plaster of less coherence and density. on the other hand, where granular crystalline gypsum has been used, setting begins at the surface of each group of crystals before the water has penetrated to the interior; the hydration is in consequence more gradual, and resistance being offered to the expansion of the inner parts, a harder and denser material is obtained. that this expansion contains an element of truth is indicated by the practice of employing the granular crystalline variety for the preparation of moulding plaster. the explanation appears, however, to be inadequate in several respects, especially in view of the fact that plasters for moulding are reduced to a fine state of division before use. it seems as if this treatment must, in great part at any rate, break up the crystalline aggregates. in order to discover a more satisfactory explanation, let us examine the results of the chemical analysis of plasters used in commerce. one is struck by the large percentage of water they usually contain. thus, four samples of ordinary plaster analyzed by landrin have an average of . per cent. of caso and . per cent. of water, while two samples of best plaster contained . per cent. of caso and . per cent. of water. these numbers do not add up to , the difference being due to silica and other impurities of the original gypsum, amounting altogether to about per cent. it might be suggested that the reason why these plasters set more slowly than completely dehydrated plaster is owing simply to the fact that they contain, apparently, some unaltered gypsum, which serves to _dilute_ the action. were this so, a similar result, as far as time of setting is concerned, should be obtained with a plaster containing a corresponding quantity of dead-burnt material. this, however, is not found to be the case. the time of setting appears, then, to be connected in some special and peculiar manner with the retention of water by the burnt plaster. the following explanation of this connection is offered, an explanation only tentative at present, owing to want of experimental data. the following substances are known: gypsum, and set plaster, caso + h o, containing . per cent. of water. plaster completely burned at moderate temperature, caso , probably amorphous. anhydrite and dead-burned plaster, caso , crystalline. selenitic deposit from boilers, caso + h o, or caso + / h o, containing . per cent. of water. the circumstance that the hot calcium sulphate can crystallize with / its normal amount of water indicates that for this proportion of water it has a greater attraction than for the other / . having a similar bearing is the fact that when burned at lower temperatures, gypsum only loses the last portions of water with extreme slowness. now, if it be the case that anhydrous calcium sulphate has a greater attraction for the first half molecule of water, then the operation of hydration will proceed very rapidly at first, more slowly afterward. many such cases are known, e.g., that of copper sulphate. conversely, if only / of the water of hydration be expelled during the baking of gypsum, the material obtained should hydrate itself more slowly. for our present purpose it will be convenient to recalculate the numbers given by landrin (_vide supra_) so as to make the calcium sulphate and water add up to . this treatment of the numbers gives a mean result for the six analyses of . per cent. of water, the amounts not varying by more than per cent. it will be seen that the dehydration has never passed the composition corresponding to caso + h o; indeed, the material approximates more nearly to the composition caso + h o. it appears probable, therefore, that in the successful preparation of plaster the whole, or nearly the whole, of the gypsum is changed, but that this change does not result in the production of caso , or of a mixture of caso and caso + h o, but of a lower hydrate of calcium sulphate. in the case of the analyses, given by landrin, of fine plaster for potteries, the percentages of water ( . and . ) correspond closely to that of a hydrate, caso + h o, which would contain . per cent. of water. some surprise may have been excited by the fact that the well known method of revivifying hydrated calcium sulphate has recently formed the subject of a patent (eng. pat., no. , ). the method described in the specification consists in reducing the materials (waste moulds, etc.) to small lumps, and baking between the temperatures of ° and °. it is mentioned that the whole of the water must not be expelled. this is no doubt correct, but it must be effected by regulating the _time_ of baking, since by prolonging the operation all the water of crystallization can be expelled far below °. to secure even baking the mass is kept stirred by mechanical stirrers, a necessary precaution, since the operation is to be carried out in an ordinary kiln. the process is stopped when a portion of the plaster is found to set in the required time, a method of regulation which will probably be found to work well in practice.--_chem. trade jour._ * * * * * spacing the frets on a banjo neck. by prof. c.w. maccord. the amateur performer on the banjo, if he be of a mechanical turn, is often tempted to exercise his skill by making an instrument for himself; and the temptation is the greater because he can confine himself to the essentials. the excellence of a banjo in respect to power and tone depends mainly upon the rim and the neck, that is, supposing the parchment head to be of proper quality; but then the preparation of the heads is a business of itself, and the amateur is no more expected to make the head than to make the strings. so again, all the minor accessories, such as pegs and tail pieces, brackets and bridges, are kept in stock for his benefit, and he may justly claim all the credit if his efforts in connection with the two principal parts first mentioned result in the production of a superior instrument. among these ready-made items is a "fret wire" of peculiar section, furnished with a flange ready for insertion into fine saw cuts across the neck, which much facilitates his work. of course, the correctness of the notes depends entirely upon the accuracy with which the frets are spaced, and the accompanying diagram exhibits a convenient method of determining the spaces by graphic means. [illustration: spacing for banjo frets] it is to be understood that when the distance from the "nut," n, to the bridge, b, has been determined, the first fret is to be placed at / of that distance from the nut, the distance from the first to the second is to be / of the remainder, and so on. to determine these distances by computation, then, is a simple enough arithmetical exercise; but it is exceedingly tedious, since the denominators of the fractions involved increase with great rapidity; being successive powers of the comparatively large number , they soon become enormous. in the large diagram, the distance, a c, on the horizontal line corresponds to the distance, n b, on the instrument. at a erect a vertical line, and mark upon it a point b such that b c shall be exactly eighteen times any convenient unit, b i. in the illustration b c is inches, and b i is / inches, so that b c is inches in length. about c as a center describe the arcs, b l, i k, and through i draw a vertical line, cutting b l in d; draw the radius d c, cutting the inner arc, i k, in j, through j draw another vertical, cutting b l in e, and so on. in the triangles, a b c, d c, e c, we have b i = d j = e f = / of the hypotenuse in each case, therefore the bases, a c, c, c, are divided in the same proportion, as required, at the points , , . and we might extend the arcs, b l, i k, and repeat the above operation until all the frets were located. but should that be done, the diagram might become inconveniently large, and some of the intersections might not be reliably determined. in order to avoid this, the spacing of the outer arc may be stopped at any convenient division, as l. the vertical by which that point is determined cuts b c at b', and through b' a new arc, b' l', is described. through the points in which this arc cuts the radial lines already drawn, a new series of verticals is passed, which will divide another portion of a c as required, and by repeating this process the spacing of the whole neck may be effected by a diagram of reasonable size. * * * * * glove making. glove making is almost a century old in this country, having been begun in the neighborhood of gloversville and johnstown, n.y., about . until the manufacture of gloves in fulton county, although even then the chief manufacturing industry, was of comparatively small importance. gloversville and johnstown were then quiet villages of from three to four thousand people. the flourishing establishments of to-day, or such of them as then existed, were small and comparatively unimportant. in the stimulating influence of a high protective tariff showed itself in the increased business at gloversville, johnstown, and the adjoining hamlet, kingsboro. these became at once the leading sources of supply for the home market gloves of a medium grade. the quality of the product has steadily improved, and the variety has been increased, until now american-made gloves are steadily driving out the foreign gloves. the skill of american glovers is equal to that of foreign glove makers, and in some respects--notably in the quality of the stitching, and, in some grades, the shape--the american gloves are the best. foreign expert workmen have been drawn over here from the great glove centers of europe, so that the greatest skill has been secured here. the annual value of the glove industry in fulton county has reached about $ , , . one hundred and seventy-five glove makers and , people in fulton county draw their subsistence directly from glove making. some of the firms have a business reaching from $ , to $ , yearly. the majority, however, have small shops, and do a small but profitable business. most of the work in fulton county, as abroad, is done at the homes of the workers. the streets of gloversville and johnstown are lined with pretty and tasteful homes, in which the hum of the sewing machine is constantly heard during the working hours of the day, but the workers are exceptionally fortunate in being able while earning good wages to enjoy all the comforts and surroundings of home, and in being practically their own masters and mistresses. before the leather can be cut and sewed into the handsome articles that are sold over the counters of the retail dry goods houses and furnishing goods stores as gloves, the skins from which they are made must be specially prepared. the two important points in this preparation are the removal of the albuminous portion of the skin and the retention and chemical changing of the gelatinous part, so that it shall become pliable, elastic, and resist decomposition. there are various methods which produce these results, and they are technically known as tanning, alum dressing, oil dressing, and indian dressing. each method produces a leather distinctly different from that produced by any other. all the preliminary processes of these various methods are alike in principle, although they vary somewhat in detail. the object in all is to remove the hair from the hide, separate the fleshy and albuminous matter, and leave only the gelatinous, which alone is susceptible to the chemical action and can be transformed by it into leather. when the skins are received in the factory they are thoroughly soaked to open out the texture and prepare them for the removal of the hair. then the skins are placed in vats of lime water, where, for two or three weeks, the lime works into the flesh and albuminous matter, and loosens the hair. the skins having thus been properly softened, the dirty but picturesque operation of beaming for removing the hair ensues. before each beamer, as the workman is called, is an inclined semi-cylindrical slab of wood covered with zinc. the skin is first spread upon this, and the broad, curved beam of the knife glides across it from end to end, scraping and removing all the loosened hair, the scarf skin, and the small portion of animal matter adhering to the skin. after the unhairing, kid skins must be fermented in a drench of bran, whose purpose is to completely decompose the remaining albuminous matter, and also to remove all traces of the lime. the operation is extremely delicate. while the gelatine is not so sensitive to the decomposing action of the ferment, nevertheless great care is required to prevent overfermentation and resulting damage to the texture of the skin. it is impossible for even the most experienced to tell just how long the fermentation should continue. sometimes the work is done in two or three hours, and sometimes it requires as many days. incessant watchfulness both day and night is required to detect the critical moment. with the less delicate skins this bran bath is not necessary. lime and acid solutions accomplish the same purpose. when the gelatine matter is all removed the skins are ready for the actual curative process. oil dressing or indian dressing--which merely differ in application, but are founded upon the same principle--is the most simple method of curing skins. the principle of each is the soaking of the gelatine fibers of the skin with oil, the union of the latter and the gelatine appearing in the form of oxide, and resulting in the insoluble, undecomposable, pliant, and tough material known to the commercial world as leather. the first step in the oil dressing, after the skins have been duly soaked to render them porous and absorptive, is to cover them with fish oil and place them in the stocks or fulling machines--huge wooden hammers with notched faces working in iron cases--where they are beaten and turned, and subjected to a uniform pressure until the oil is gradually absorbed. after taking them out, hanging them up, and stretching them, the oil and fulling process is repeated according to the thickness of the skin, and until every part of it is full of oil. after this the skins are dried in a mild heat that causes the oxidization of the oil. this being completed, all the superfluous oil is removed by putting the skins in an alkali bath. then the curing process is complete. with the preparation of kid leather alum is the astringent curative agent. its operation is accompanied by that of others whose purpose is to secure elasticity and pliability, and mainly to preserve that beautiful texture which makes kid leather superior to all others. these assistants in the process are eggs, flour, and salt. they are combined into what is called a custard. a proper quantity of the custard and a number of skins having been put together in a dash wheel, where they are thrown about for some time, the open pores of the skin absorb the custard freely, and become swelled by the chemical union of the custard and the skin. in trade parlance this swelling is known as "plumping." this having progressed satisfactorily, the skins are folded together with the fleshy side outward, and are dried by a gentle heat. they are now cured, but they are yet hard and rough. another objectionable feature is that they are of unequal thickness. breaking and staking, as they are called, are now resorted to, to make the skins soft, pliable, and of even texture, removing the superfluous chemicals with which they become charged, and the stiffness by manipulating the fibers. much trained skill and dexterity, especially in knee and arm staking, are required in the stretching, which is the essential feature of these operations. breaking is first resorted to. the break beam, which is armed at each end with a knife edge, oscillates up and down. in a frame beneath it the operator stretches the dried and stiff skin. the break beam comes down upon the skin, stretches and softens it, and removes much surplus custard. the operator presents a new surface to each stroke of the break beam, and in a very short space of time the entire skin is rendered soft and pliable. further manipulation upon the arm or knee stake--of which a dull, semicircular knife blade, supported upon a suitable standard upon the floor or upon a beam about opposite the worker's elbow is the main feature--is required. the skin must be drawn across this knife blade with a considerable application of force so as to reduce the unduly thick parts, stretch the skin and secure a uniform thickness suitable for gloves. much dexterity, especially in the case of fine skins, is required in this operation to avoid cutting or tearing. the operator places the fleshy side of the skin over the knife, grasps the two ends of the skin, and placing his knee upon it and slowly drawing the skin across the knife edge, he brings his weight to bear upon it. if the operator is skilled and experienced the skin yields quickly, when needed, to the strain applied and a uniform texture is secured. the operation of transforming the skin into leather is now finished, but age is necessary to secure perfect pliability and softness. the skins are, therefore, laid away to let the slow chemical operation going on within them be completed. the visitor can now watch the further processes of manufacture by visiting the dye rooms. skins which have already been aged are immersed in dye vats, where the delicate colors are imparted to them. the same care is not required in obtaining the ordinary range of dark colors, for these are "brushed" on, the skin being spread upon a glass slab and the dye being painted on with a brush. after they are dyed the skins are sometimes somewhat hard, and in some classes have to be staked again in order to restore their pliability. the finishing touches to a kid skin are secured by rubbing the grain side over with a size, which imparts a gloss. the experience of gloversville manufacturers with "buck" gloves has enabled them to impart a special finish to a skin which is very popular under the title of "mocha." this is the same as suede finish, which is produced in other countries by shaving off the grain side of the skin at an early stage of its progress. the gloversville method is much better, however, and has more perfect results. here the grain is removed, and the velvet finish secured by buffing the surface on an emery wheel. the surface of the leather is cut away in minute particles by this process, and the result is an exceedingly even and velvety texture, superior to that obtained by other methods. european manufacturers do not approach the americans in this respect. the leathermaker leaves off and the glovemaker begins. a marble slab lies before the cutter on a table, and every particle of dirt or other inequality is removed before "doling." the skin is spread, flesh side up, upon the slab, and the cutter goes over it with a broad bladed chisel or knife, shaving down inequalities and removing all the porous portions. the dexterity with which this is done makes the operation appear extremely simple, but any but a skilled and experienced operative would almost surely cut through the skin. the most delicate part of the glovemaker's art, in which exact judgment is required, comes in preparing the "tranks" or slips, from which the separate gloves are cut. the trank must be so cut as to have just enough leather to make a glove of a certain size and number. the operation would be easy enough if the material were hard and stiff, and if the elasticity were uniform, but this is rarely the case. to accomplish this operation the trank must be firmly stretched in one direction, and while so stretched a "redell" stamps the proper dimensions in the other direction, to which the leather is trimmed. upon the nicety with which this operation is performed depends the question of whether the finished glove will stretch evenly or too much or too little in one direction or the other. after this the trank or outline of the glove must be cut out. in olden times of glove manufacture an outline was traced upon the leather and the pattern was cut with shears. modern invention has produced dies and presses which are universally used. the steel die has the outline of a double glove, including the opening for the thumb piece. the die rests upon the bed of the press. several tranks are laid upon it, the lever is drawn, and in a moment the blanks are cut out clean and smooth. the gussets, facings, etc., are cut from the waste leather in the thumb opening at the same operation. similar dies are used in the cutting of the thumb pieces and fourchettes or strips forming the sides of the fingers. the pieces now go to the great sewing rooms of the factory, where are long rows of busy sewing girls. if the manufacturer of years ago could revisit the scenes of his earthly toil, and wander through the sewing rooms of a modern factory, he would doubtless be greatly amazed at the sight presented there. in his day such a thing was unknown. the glove was then held in position by a hand clamp, while the sewing girl pushed the needle in and out, making an overseam. all this is done now in an infinitely more rapid manner by machine, and with resulting seams that are more regular and strong than those made by the hand sewer. the overseam sewers earn large wages, and their places are much coveted. overlapping seams are produced on the pique machine, which is a most ingenious mechanism. the essential feature of this machine is a long steel finger with a shuttle and bobbin working within, and the finger of the glove is drawn upon this steel finger, permitting the seam to be sewn through and through. the visitor to the factory can see also the minor operations of embroidering, lining--in finished gloves--sewing the facing, sewing the buttonholes, putting on the buttons, and trimming with various kinds of thread. before the gloves are ready for the boxes one more operation remains. the gloves are somewhat unsightly as they come from the sewers' hands, and must be made trim and neat. to secure these desirable results the gloves are taken to the "laying-off" room. in this are long tables with a long row of brass hands projecting at an acute angle. these are filled with steam and are too hot to touch. these steam tables by ingenious devices are so arranged that it is impossible to burn the glove or stiffen the leather by too much heat, a common defect in ordinary methods. the operation of the "laying-off" room is finished with surprising quickness. before each table stands an operator, who slips a glove over each frame, draws it down to shape, and after a moment's exposure to the warmth removes it, smooth, shapely, and ready for the box. the frames upon which the gloves are drawn are long and narrow for fine gloves and short and stubby for common ones. then the glove is taken to the stock room, where there are endless shelves and bins to testify to the chief drawback to glove making, the necessity for innumerable patterns.--_the mercer._ * * * * * fabric for upholstery purposes. the object of this invention is to produce a firm, solid, dust-resisting, and durable woven cloth, composed, preferably, entirely of cotton, but it may be of a cotton warp combined with a linen or other weft, and is particularly applicable for covering the seats and cushions of railway and other carriages, for upholstering purposes, for bed ticking, and for various other uses. to effect this object, a cotton warp and, preferably, a cotton weft also are employed, or a linen, worsted, or other weft may be used. both the yarns for warp and weft may be either dull or polished, according to the appearance and finish of cloth desired. the fabric is woven in a plain loom, and the ends are drawn through say eight heald shafts, but four, sixteen, or thirty-two heald shafts might be employed. when eight heald shafts are employed, the warp is drawn as follows: the st warp end in the first heald shaft, the d warp end in the second heald shaft, and so on, the remaining six warp ends being drawn in, in consecutive order, through the remaining six heald shafts; the th warp end is drawn in through the first heald shaft, and so on, the drawing in of the other ends being repeated as above. the order of the shedding is as follows: st change. the st and d heald shafts fall, the rest remaining up. d change. the th and th shafts fall, and the st and d rise. d change. the d and th shafts fall, and the th and th rise. th change. the th and th shafts fall, and the d and th shafts rise. the result is that each weft thread, a, passes under six warp threads, b, and over two warp threads, in the manner illustrated by the accompanying diagram. in drawing in, when four heald shafts are employed, the st warp end is drawn in through the st heald shaft, the d through the d shaft, the d through the st, the th through the d, the th through the d, the th through the th, the th through the d, and th through the th shaft, and repeating with the th end through the st shaft. in shedding, the st heald shaft is lowered, then the d, then the d, and then th. the result, in this case, is still the same, viz., that each weft thread passes under six warp ends and over two warp ends. although a cotton warp is spoken of in some cases, worsted or other yarn can be added to the cotton warp to obtain a variation in the pattern or design.--_jour. of fabrics._ [illustration] * * * * * reversible ingrain or pro-brussels carpet. the object of this invention is to manufacture, in a cheap fabric, a closer imitation of brussels carpets. as is well known, an ordinary brussels carpet is made with a pattern on one side only, but according to this invention, it is intended to produce a pattern on both sides of the ingrain or pro-brussels carpet, so that it will be reversible. in manufacturing a reversible carpet of this class according to the present invention, the pattern is formed by means of the warp and weft combined, and any suitable ingrain warp operated by the harness or jacquard of the loom may be used. in combination with ingrain warp, a fine catching or binding warp, operated by the gear or jacquard harness of the loom, is employed, such fine catching warp being used to bind the weft into the fabric, therefore, if the fabric be woven two-ply, the ingrain warps are thrown on both the under and upper surfaces of the fabric, as well as in between the weft, according to the pattern being woven, by which means four colors are shown on both sides of the fabric, two being produced by the weft, and two by the ingrain warps. more than four colors, however, can be produced upon each side by multiplying the number of colored wefts and warps employed. if the fabric woven be a three-ply, with the addition of the ingrain warps thrown on each face of the fabric, then five or more colors would be imparted to the carpet, as any number of colors can be used to form a given pattern, by planting or arranging the colors in the warp, and the remaining colors by the wefts, and so on. the ingrain warp thread, therefore, together with the weft, used as stated above, produces an effective pattern on both sides of the carpet; consequently, it becomes reversible, and this can be accomplished whether the carpet woven be two, three, or other number of ply. by reference to the accompanying sheets of drawings, this invention will be better understood. fig. is an enlarged cross section of an improved carpet, a three-ply, that is to say, it is a carpet wherein three shuttles are employed, each carrying a differently colored weft; a represents the weft threads which may be composed of any suitable fiber, b and c are cotton or other fine warp threads, which are employed for binding the weft together, while d and e represent the ingrain or woolen warp, where it will be seen that each ingrain warp, besides lying between the weft, is thrown on both sides of the fabric, for the purpose of forming figures thereon. it will, therefore, be seen that a carpet made according to fig. will show five colors--three colors produced by the weft and two colors produced by the ingrain warp. fig. represents a carpet made with two-ply, in which case only four colors will be produced, two by the weft and two by the ingrain warp. it is, consequently, obvious that a carpet made in the manner above described will have a corresponding pattern or figure on both its sides, allowing it to be used on both sides. fig. also shows a two-ply carpet, but, in this case, six colors are produced, i.e., two colors by the weft and four by the ingrain warp, marked d, d¹, e, and e¹, the warp being so manipulated by the harness as to make the carpet reversible, and having a corresponding pattern or figure on both sides.--_journal of fabrics._ [illustration: fig. ] [illustration: fig. ] [illustration: fig. ] * * * * * arÆo-picnometer. a modified aræometer has been recently patented by aug. eichhorn, in dresden, germany (deutsches reichs-patent, no. , ), which will prove a great boon to chemists, distillers, physicians, etc., as it affords an easy means of determining the specific gravity of liquids, especially such of which only small quantities can be conveniently obtained. with the ordinary aræometers, as hitherto constructed, a considerable quantity of the test fluid is required, and an elaborate calculation necessary for each determination. in the new aræo-picnometer these drawbacks are ingeniously avoided, so that the specific gravity of any liquid can be quickly and easily obtained with astonishing accuracy. the new and important feature of this instrument consists in a glass bulb, c--see accompanying sketch--which is filled with the liquid whose gravity is to be determined. thus, instead of floating the entire apparatus in the test fluid, only a very small quantity of the latter is required, an advantage which can hardly be overestimated, considering how difficult it is in many instances to procure the necessary supply. [illustration] ^ = = = = a = = \ = / | = | |~~~~~~~~~~~~~~| | - - = - -| |- - = - | | - - = - -| |- - = - | | - / \ -| |- - | b | - | | \ / -| |- e//¯ ¯\\d | | - | c | -| |- \ _ / | | - \ / -| |- = - | | - = -| |- | | - | | - \f/ -| |- - v - | | -| / \ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ the glass bulb, c, when filled with the test fluid, is closed by means of an accurately fitting glass stopper, d, and the instrument is then placed in a glass cylinder filled with distilled water of . deg. temperature (centigrade). the gravity is then at once shown on the divided scale in the tube, a. the lower bulb, f, contains some mercury; e is a small glass knob, which serves to maintain the balance, while b is an empty glass bulb (floater). these instruments are admirably adapted for determining the gravity of alcohol, petroleum, benzine, and every kind of oil, also for testing beer, milk, vinegar, grape juice, lye, glycerine, urine, etc. as the process is an exceedingly simple one and free from the drawbacks of the aræometer, we are justified in concluding that the aræo-picnometer will soon be in general use. h. hensoldt, ph.d. petrographical laboratory, school of mines, columbia college. * * * * * [continued from supplement, no. , page .] gaseous illuminants.[ ] [footnote: lectures recently delivered before the society of arts, london. from the _journal_ of the society.] by prof. vivian b lewes. iv. mr. frank livesey, in the concluding sentence of a paper read before the southern district association of gas managers and engineers during the past month, on "a ready means of enriching coal gas," speaking of enrichment by gasolene by the maxim-clarke process, said "it should, in many cases, take the place of cannel, to be replaced in its turn, probably, by a water gas carbureted to or candle power." and now, having fully reviewed the methods either in use or proposed for the enrichment of gas, we will pass on to this, the probable cannel of the future. discovered by fontana, in , and first worked by ibbetson, in england, in , water gas has added a voluminous chapter to the patent records of england, france, and america, no less than sixty patents being taken out between and , in which the action of steam on incandescent carbon was the basis for the production of an inflammable gas. up to the latter date the attempts to make and utilize water gas all met with failure; but about this time the subject began to be taken up in america, and the principle of the regenerator, enunciated by siemens in , having been pressed into service in the water-gas generator under the name of fixing chambers or superheaters, we find water gas gradually approaching the successful development to which it has attained in the united states during the last ten years. having now, by the aid of american skill, been brought into practical form, it is once more attempting to gain a foothold in western europe--the land of its birth. when carbon is acted upon at high temperatures by steam, the first action which takes place is the decomposition of the water vapor, the hydrogen being liberated, while the oxygen unites with the carbon to form carbon dioxide: carbon. water. c + h o = co + h and the carbon dioxide so produced interacts with more red-hot carbon, forming the lower oxide--carbon monoxide: co + c = co so that the completed reaction may be looked upon as yielding a mixture of equal volumes of hydrogen and carbon monoxide, both of them inflammable but non-luminous flames. this decomposition, however, is rarely completed, and a certain proportion of carbon dioxide is invariably to be found in the water gas, which, in practice, generally consists of a mixture of about this composition: water gas. hydrogen . carbon monoxide . carbon dioxide . nitrogen . methane . sulphureted hydrogen . oxygen . ------ . the above is an analysis of water gas made from ordinary gas coke in a van steenbergh generator. the ratio of carbon monoxide and carbon dioxide present entirely depends upon the temperature of the generator, and the kind of carbonaceous matter employed. with a hard, dense anthracite coal, for instance, it is quite possible to attain a temperature at which there is practically no carbon dioxide produced, while with an ordinary form of generator and a loose fuel like coke, a large proportion of carbon dioxide is generally to be found. the sulphureted hydrogen in the analysis quoted is, of course, due to the high amount of sulphur to be found in the gas coke, and is practically absent from water gas made with anthracite, while the nitrogen is due to the method of manufacture, the coke being, in the first instance, raised to incandescence by an air blast, which leaves the generator and pipes full of a mixture of nitrogen and carbon monoxide (producer gas), which is carried over by the first portions of water gas into the holder. the water gas so made has no photometric value, its constituents being perfectly non-luminous, and attempts to use it as an illuminant have all taken the form of incandescent burners, in which thin mantles or combs of highly refractory metallic oxides have been heated to incandescence. in carbureted water gas this gas is only used as the carrier of illuminating hydrocarbon gases, made by decomposing various grades of hydrocarbon oils into permanent gases by heat. many forms of generator have been used in the united states for the production of water gas, which, after or during manufacture, is mixed with the vapors and permanent gases obtained by cracking various grades of paraffin oil, and "fixing" them by subjecting them to a high temperature; and in considering the subject of enrichment of coal gas by carbureted water gas, i shall be forced, by the limited time at my disposal, to confine myself to the most successful of these processes, or those which are already undergoing trial in this country. in considering these methods, we find they can be divided into two classes: . continuous processes, in which the heat necessary to bring about the interaction of the carbon and steam is obtained by performing the operation in retorts externally heated in a furnace; and . intermittent processes, in which carbon is first heated to incandescence by an air blast, and then, the air blast being cut off, superheated steam is blown in until the temperature is reduced to a point at which the carbon begins to fail in its action, when the air is again admitted to bring the fuel up to the required temperature, the process consisting of alternate formation of producer gas with rise of temperature, and of water gas with lowering of the temperature. of the first class of generator, none, as far as i know, have as yet been practically successful, the nearest approach to this system being the "meeze," in which fire clay retorts in an ordinary setting are employed. in the center of each retort is a pipe leading nearly to the rear end of the retort, and containing baffle plates. through this a jet of superheated steam and hydrocarbon vapor is injected, and the mixture passes the length of the inner tube, and then back through the retort itself--which is also fitted with baffle plates--to the front of the retort, whence the fixed gases escape by the stand pipe to the hydraulic main, and the rich gas thus formed is used either to enrich coal gas or is mixed with water gas made in a separate generator. in some forms the water gas is passed with the oil through the retort. in such a process, the complete breaking down of some of the heavy hydrocarbons takes place, and the superheated steam, acting on the carbon so liberated, forms water gas which bears the lower hydrocarbons formed with it; but inasmuch as oil is not an economical source of carbon for the production of water gas, this would probably make the cost of production higher than necessary. this system has been extensively tried, and indeed used to a certain extent, but the results have not been altogether satisfactory, one of the troubles which have had to be contended with being choking of the retorts. of the intermittent processes, the one most in use in america is the "lowe," in which the coke or anthracite is heated to incandescence in a generator lined with firebrick, by an air blast, the heated products of combustion as they leave the generator and enter the superheaters being supplied with more air, which causes the combustion of the carbon monoxide present in the producer gas, and heats up the firebrick "baffles" with which the superheater is filled. when the necessary temperature of fuel and superheater has been reached, the air blasts are cut off, and steam is blown through the generator, forming water gas, which meets the enriching oil at the top of the first superheater, called the 'carbureter,' and carries the vapors with it through the main superheater, where the "fixing" of the hydrocarbons takes place. the chief advantage of this apparatus is that the enormous superheating space enables a lower temperature to be used for the "fixing." this does away, to a certain extent, with the too great breaking down of the hydrocarbons, and consequent deposition of carbon. this form of apparatus has just found its way to this country, and i describe it as being the one most used in the states, and the type upon which, practically, all water gas plant with superheaters has been founded. the springer apparatus, which is under trial by one of the large gas companies, differs from the lowe merely in construction. in this apparatus the superheater is directly above the generator; and there is only one superheating chamber instead of two. the air blast is admitted at the bottom, and the producer gases heat the superheater in the usual way, and when the required temperature is reached, the steam is blown in at the top of the generator, and is made to pass through the incandescent fuel, the water gas being led from the bottom of the apparatus to the top, where it enters at the summit of the superheater, meets the oil, and passes down with it through the chamber, the finished gas escaping at the middle of the apparatus. this same idea of making the air blast pass up through the fuel, while in the subsequent operation the steam passes down, is also to be found in the loomis plant, and is a distinct advantage, as the fuel is at its hottest where the blast has entered, and, in order to keep down the percentage of carbon dioxide, it is important that the fuel through which the water gas last passes should be as hot as possible, to insure its reduction to carbon monoxide. the flannery apparatus is again but a slight modification of the lowe plant, the chief difference being that, as the gas leaves the generator, the oil is fed into it, and, with the gas, passes through a d-shaped retort tube, which is arranged round three sides of the top of the generator; and in this the oil is volatilized, and passes, with the gas, to the bottom of the superheater, in which the vapors are converted into permanent gases. the van steenbergh plant, with which i have been experimenting for some time, stands apart from all other forms of carbureted water gas plant, in that the upper layer of the fuel itself forms the superheater, and that no second part of any kind is needed for the fixation of the hydrocarbons, an arrangement which reduces the apparatus to the simplest form, and leaves no part which can choke or get out of order, an advantage which will not be underrated by any one who has had experience of these plants. while, however, this enormous advantage is gained, there is also the drawback that the apparatus is not fitted for use with crude oils of heavy specific gravity, such as can be dealt with in the big external superheaters of the lowe class of water gas plant, but the lighter grades of oil must be used in it for carbureting purposes. i am not sure in my own mind that this, which appears at first a disadvantage, is altogether one, as, in the first place, the lighter grades of oil, if judged by the amount of carbureting power which they have, are cheaper per candle power, added to the gas, than the crude oils, while their use entirely does away with the formation of pitch and carbon in the pipes and purifying apparatus--a factor of the greatest importance to the gas manufacturer. the fact that light oils give a higher carburation per gallon than heavy crude oil is due to the fact that the latter have to be heated to a higher temperature to convert them into permanent gas, and this causes an over-cracking of the most valuable illuminating constituents; and this trouble cannot be avoided, as, if a lower temperature is employed, easily condensible vapors are the result, which, by their condensation in the pipes, give rise to much trouble. the simplicity of the apparatus is a factor which causes a great saving of time and expense, as it reduces to a minimum the risk of stoppages for repairs, while the initial cost of the apparatus is, of course, low, and the expense of keeping in order practically _nil_. when i first made the acquaintance of this form of plant, a few years ago, the promoters were confident that nothing could be used in it but american anthracite, of the kind they had been in the habit of using in america, and a light naphtha of about . specific gravity, known commercially as deg baume. a few weeks' work with the apparatus, however, quickly showed that, with a slightly increased blow, and a rather higher column of fuel, gas coke could be used just as well as anthracite, and that by increasing the column of fuel, a lower grade of oil could be employed; so that during a considerable portion of the experimental work nothing but gas coke from the horseferry road works and a petroleum of a specific gravity of about . were employed. having had control of the apparatus for several months, and, with the aid of a reliable assistant, having checked everything that went in and came out of the generator, i am in a position to state authoritatively that, using ordinary gas coke and a petroleum of specific gravity ranging from . to . , , cubic feet of gas, having an illuminating power of twenty-two candles, can be made with an expenditure of to lb. of coke and / gallons of petroleum. the most important factors, i.e., the quantity of petroleum and the illuminating value of the gas, have also been checked and corroborated by mr. heisch and mr. leicester greville. total gas made = , cubic feet. time taken: blowing. hour. time taken: making. minutes. fuel used: gas coke. lb. = lb. per , c.f. fuel used: naphtha, sp. gr. . . gals. = . gals. per , c.f. illuminating power of gas = . candles. i must admit that these results far exceeded my expectations, although they only confirmed the figures claimed by the patentee; and there are not wanting indications that, when worked on a large scale and continuously, they might be even still further lowered, as it is impossible to obtain the most economical results when making less than , cubic feet of the gas, as the proper temperature of the walls of the generator are not obtained until after several makes; and it is only after about , cubic feet of gas has been made that the best conditions are fulfilled. it will enable a sounder judgment to be formed of the working of the process if the complete experimental figures for a make of gas be taken. composition of the gas. hydrogen. . olefines. . ethane. . methane. . carbon monoxide. . carbon dioxide. . oxygen. . nitrogen. . ------- . unpurified gas contained carbon dioxide. . per cent. sulphureted hydrogen. . " total sulphur per cu. ft. = . ammonia. nil bisulphide of carbon. nil gas produced naphtha used gals. pts. st. make. , cu. ft. d. " , " d. " , " ------ --- -- , the last portion of the table shows the economy which arises as the whole apparatus gets properly heated. thus the first make used gallons naphtha per , cubic feet, the second gallons pints per , cubic feet, and the third gallons pints per , cubic feet, and it is, therefore, not unreasonable to suppose that in a continuous make these figures could be kept up, if not actually reduced still lower. in introducing the oil it is not injected, but is simply allowed to flow in by gravity, at a point about half way up the column of fuel, the taps for its admission being placed at intervals around the circumference of the generator, and oil at first begins to flow down the inside wall of the generator, but being vaporized by the heat, the vapor is borne up by the rush of steam and water gas, and is cracked to a permanent gas in the upper layer of fuel. this i think is the secret of not being able to use heavier grades of oil, these being sufficiently non-volatile to trickle down the side into the fire box at the bottom, and so to escape volatilization. i have tried to steam-inject the oil, but have not found that it yields any better results. one of the first things that strikes any one on seeing a make of gas by this system is the enormous rapidity of generation. mr. leicester greville, who is chemist to the commercial gas company, in reporting on the process, says, "the make of gas was at the rate of about , cubic feet in hours. a remarkable result, taking into consideration the size of the apparatus." it is quite possible, with the small apparatus, to make , cubic feet in hours; indeed the run for which the figures are given are over this estimate; and it must be borne in mind that this rapidity of make gives the gas manager complete control over any such sudden strains as result from fog or other unexpected demands on the gas-producing power of his works; while a still more important point is that it does away with the necessity of keeping an enormous bulk of gas ready to meet any such emergency, and so renders unnecessary the enormous gasholders, which add so much to the expense of a works, and take up so much room. perhaps the greatest objection to water gas in the public mind is the dread of its poisonous properties, due to the carbon monoxide which it contains; but if we come to consider the evidence before us on the increase of accidents due to this cause, we are struck by the poor case which the opponents of water gas are able to make out. no one can for a moment doubt the fact that carbon monoxide is one of the deadliest of poisons. it acts by diffusing through the air cells of the lungs, and forming, with the coloring matter of the blood corpuscles, a definite compound, which prevents them carrying on their normal function of taking up oxygen and distributing it throughout the body, to carry on that marvelous process of slow combustion which not only gives warmth to the body, but also removes the waste tissue used up by every action, be it voluntary or involuntary, and by hindering this, it at once stops life. all researches on this subject point to the fact that something under one per cent. only of carbon monoxide in air renders it fatal to animal life, and this at first seems an insuperable objection to the use of water gas, and has, indeed, influenced the authorities in several towns, notably paris, to forbid its introduction for domestic consumption. let us, however, carefully examine the subject, and see, by the aid of actual figures, what the risk amounts to compared with the risks of ordinary coal gas. many experiments have been made with the view of determining the percentage of carbon monoxide in air which is fatal to human or, rather, animal life, and the most reliable as well as the latest results are those obtained by dr. stevenson, of guy's hospital, in consequence of the two deaths which took place at the leeds forge from inhaling uncarbureted water gas containing per cent. of carbon monoxide. he found that one per cent. visibly affected a mouse in one and a half minutes, and in one hour and three quarters killed it, while one-tenth of a per cent. was highly injurious. let us, for the sake of argument, take this last figure . per cent. as being a fatal quantity, so as to be well within the mark. in ordinary carbureted water gas as supplied by the superheater processes, such as the lowe, springer, etc., the usual percentage of carbon monoxide is per cent., but in the van steenbergh gas--for certain chemical reasons to be discussed later on--it is generally about per cent., and rarely rises to per cent. an ordinary bedroom will be say ft. x ft. x ft., and will therefore contain , cubic feet of air, and such a room would be lighted by a single bats-wing burner consuming not more than four cubic feet of gas per hour. suppose now the inmate of that room retires to bed in such a condition of mental aberration that he prefers to blow out the gas rather than take the ordinary course of turning it off--a process, by the way, of putting out gas which is decidedly easier in theory than in practice, especially in his presumed mental condition--you would have in one hour the , cubic feet of gas in the room mixed with four fifths of a cubic foot of carbon monoxide--the carbureted water gas being supposed to contain per cent.--or . per cent. in such a room, however, if the doors and windows were absolutely air tight, and there was no fireplace, diffusion through the walls would change the entire air once an hour, so that the percentage would not rise above . ; while in any ordinary room imperfect workmanship and an open chimney would change it four times in the hour, reducing the percentage to . , a quantity which the most inveterate enemy of water gas could not claim would do more than produce a bad headache, an ailment quite as likely to have been caused by the same factor that brought about the blowing out of the gas. moreover, we are now talking about the use of carbureted water gas as an enricher of coal gas, and not as an illuminant to be consumed _per se._ and we may calculate that it would be probably used to enrich a -candle coal gas up to . candle power. to do this per cent. of candle power carbureted water gas would have to be mixed with it, and taking the percentage of carbon monoxide in london gas at per cent.--a very fair average figure--and per cent. as the amount present in the van steenbergh gas, we have . per cent. of carbon monoxide in the gas as sent out--a percentage hardly exceeding that which is found in the rich cannel gas supplied to such towns as glasgow, where i am not aware of an unusual number of deaths occurring from carbon monoxide poisoning. the carbureted water gas has a smell every bit as strong as coal gas, and a leak would be detected with equal facility by the nose; and i think you will agree with me that the cry raised against the use of carbureted water gas, for this reason, is one of the same character that hampered the introduction of coal gas itself at the commencement of this century. we must now turn to the chemical actions which are taking place in the generator of the water gas plant, and these are more complex in the case of the van steenbergh plant than in those of the lowe type, and, for that reason, yield a gas of more satisfactory composition. taking gas as made by the lowe or springer process, and contrasting it with the van steenbergh gas, we are at once struck by several marked differences. in the first place the hydrogen is far higher and the marsh gas or methane lower in the van steenbergh than in the lowe process, this being due to the sharper cracking that takes place in the short column of cherry red coke, as compared with the lower temperature employed for a longer space of time in the lowe superheater. next we notice a difference of per cent. in the carbon monoxide, which is greatly reduced in the steenbergh generator by the carbon monoxide and marsh gas reacting on each other as they pass over the red hot surface of coke with formation of acetylene, which adds to the illuminants, this action also reducing the quantity of marsh gas present. lowe van steenbergh gas. gas. hydrogen..................... . . marsh gas.................... . . carbon monoxide.............. . . illuminants.................. . . ethane....................... ---- . carbon dioxide............... . . oxygen....................... . . nitrogen..................... . . ------ ------ . . in the illuminants, if we add the higher members of the methane series present to the olefines, we see they are about equal in each gas, while the low percentage of nitrogen in the lowe gas is due to more careful working, and could easily be attained with the van steenbergh plant by allowing the first portion of water gas to wash out the producer gas before the hopper on top is closed. the cracking of the naphtha by the red hot coke is undoubtedly a great advantage, for, as i have pointed out, the cracking of rushing petroleum is an exothermic reaction, so that the coke at the top of the generator gets hotter and hotter, and it is no unusual thing to see the coke at the beginning of the make cherry red at the bottom and dull red at the top, while at the end of the make it is almost black at the bottom and cherry red at the top, in this way attaining the same advantage in working that the springer and loomis do by their down blast, that is, having the fuel at its hottest where the gas finally leaves it, so as to reduce the quantity of carbon dioxide, and so lessen the expense of purification. it will be well now to turn for a few moments to the gas obtained by cracking the light petroleum oils by themselves. the russian and american petroleum differ so widely in composition that it was necessary to see in what way the gases obtained from them differed; and to do this, equal quantities of american naphtha and a russian naphtha were cracked, by passing through an iron tube filled with coke, and in each case heated to a cherry red heat, the gases being measured, and then analyzed, with the following results: american. russian. no. of cubic feet per gallon... ---- ---- hydrogen....................... . . methane........................ . . ethane......................... . . olefines....................... . . carbon monoxide................ . . carbon dioxide................. . . oxygen......................... . . nitrogen....................... nil. nil. ----- ----- . . showing that, if the russian oil is a little lower in illuminants, it quite makes up by extra volume, but it seemed to me to deposit a much larger proportion of carbon. taking / gallons of american naphtha, it would give roughly cubic feet of gas of the above composition, while the remaining gas would be the ordinary water gas. taking the analysis of this as given, and calculating from it what would be the composition of a mixture of it with the naphtha gas, we obtain: calculated. actual. hydrogen...................... . . methane....................... . . olefines...................... . . ethane........................ . . carbon monoxide............... . . carbon dioxide................ . . oxygen........................ . . nitrogen...................... . . sulphureted hydrogen.......... . . ------ ------ . . showing how great the effect is of the diluents in the water gas in preventing the overcracking of the hydrocarbons, as shown by the increase in the percentage of them present in the finished gas; while the enormous reduction in the amount of carbon monoxide present is due to the interaction between it and the paraffin hydrocarbons in the presence of red-hot carbon, a point which makes the van steenbergh apparatus enormously superior to any of the superheater forms of plant. after all said and done, however, the reactions taking place, although they have an intense fascination for the chemist, are not the factors which the gas manager deems the most important, the cost of any given process being the test by which it must stand or fall; and it will be well now to consider, as far as it is possible, the expense of enriching coal gas by the various methods i have brought before you. in order to be well above the prescribed limit of illuminating power at all parts of an extended service, the gas at the works must be sent out at an illuminating power of . candles and we may, i think, fairly take it that candle coal gas, as made by the big london companies, costs, as nearly as can be, s. per , cubic feet in the holder, and the question we have now to solve is the cost of enriching it from to . candle power. when this is done by cannel, the cost is . pence per candle power, so that the extra / would cost d. per , . carbureting by the vapors of gasoline by the maxim-clarke process costs / d. per , , so that the extra candle power would mean an expenditure of . d. unfortunately i have no figures upon which to calculate the cost of producing such a gas by the dinsmore process, but with the three important water gas enrichers we can deal. using russian fuel oil, which can be obtained in bulk in london at d. per gallon, the proprietors of the springer plant guarantee / candle power per , cubic feet of gas per gallon used, so that, to produce a candle gas, gallons would be used. the cost per , cubic feet may be roughly tabulated, as the coke used amounts to about lb. s. d. oil.................................... coke................................... labor and purification................. charge on plant........................ ---- twenty five per cent. of -candle gas when mixed with per cent. of the -candle gas gives the required . candle gas, which would therefore cost s. / d., or the enrichment would have cost / d. by the lowe process, an increase of . -candle power is guaranteed for the consumption of a gallon of the same oil, so that the cost would be a shade higher, all other factors remaining the same, while with the van steenbergh process both grade of oil and consumption of fuel vary from either of these processes. in order to obtain a thousand cubic feet of -candle gas, two and a half gallons of the lighter grade oil would be consumed, and i am informed that there is now no difficulty in obtaining oil of the right grade in london in bulk at d. per gallon, which would make the cost: s. d. two and a half gallons of oil........... thirty pounds of coke................... / labor and purification.................. charge on plant......................... / ------ and the enriched coal gas would, therefore, cost s. / d. per thousand, the extra / -candle power having been gained at an expense of / d. or / d. per candle. tabulating these results we have--cost of enriching a -candle gas up to . candle power per , cubic feet by cannel coal, d.; by maxim-clarke process, - / d.; by lowe or springer water gas, / d.; by van steenbergh water gas, / d. in reviewing this important subject, and bringing a wide range of experimental work to bear upon it, i have, as far as is possible, divested my mind of bias toward any particular process, and i can honestly claim that the fact of the van steenbergh process showing such great superiority is due to the force of carefully obtained experimental figures, corroborated by an experienced and widely known gas chemist, and by the chief gas examiner of the city. in adopting any new method, the mind of the gas manager must to a great extent be influenced by the circumstances of the times, and the enormous importance of the labor question is a main factor at the present moment; with masters and men living in a strained condition which may at any moment break into open warfare, the adoption of such water gas processes would relieve the manager of a burden which is growing almost too heavy to be borne. combining, as such processes do, the maximum rate of production with the minimum amount of labor, they practically solve the labor question. requiring only one-tenth the number of retort house hands that are at present employed, the carbureted water gas can be used for enrichment until troubles arise, and then the gas can be used pure and simple, with a hardly perceptible increase in expense, while the rapidity of make will also give the gas manager an important ally in the hour of fog, or in case of any other unexpected strain on his resources. one of the first questions asked by the practical gas maker will be: "what guarantee can you give that as soon as we have erected plant, and got used to the new process of manufacture, a sudden rise in the price of oil will not take place, and leave us in worse plight than we were before?" and the only answer to this is that, as far as it is possible to judge anything, this event is not likely to take place in our time. a year ago the prospects of the oil trade looked black, as the output of american oil was in the hands of a powerful ring, who seemed likely also to obtain control of the russian supplies; but, fortunately, this was averted, and, at the present moment, the russian pipe lines are flooding the market with an abundant supply, which those best able to judge tell us is practically inexhaustible, so that prices may be expected to have a downward rather than an upward tendency. but even should a huge monopoly be created, i think i have found a source of light at home which will hold its own against any foreign illuminant in the market. for a long time i have felt that in this country we had sources of light and power which only needed development, and the discovery of the right way to use them, in order to give an entirely new complexion to the question of carbureting; and now by the aid of the engineering skill and technical knowledge of mr. staveley, of baghill, near pontefract, i think it is found. at three or four of the scotch iron works the furnace gases co. are paying a yearly rental for the right of collecting the smoke and gases from the blast furnaces. these are passed through several miles of wrought iron tubing, diminishing in size from feet down to about inches; and as the gases cool, so there is deposited a considerable yield of oil. at messrs. dixon's, at glasgow, which is the smallest of these installations, they pump and collect about , , cubic feet of furnace gas per day; and recover, on an average, , gallons of furnace oils per week, using the residual gases, consisting chiefly of carbon monoxide, as fuel for distilling and other purposes, while a considerable yield of sulphate of ammonia is also obtained. in the same way a small percentage of the coke ovens are fitted with condensing gear, and produce a considerable yield of oil, for which, however, there is a very limited market, the chief use being for lucigen and other lamps of the same description, and for pickling timber for railway sleepers, etc.; the result being that, four years ago, it could be obtained in any quantity at / d. per gallon, while since that it has been as high as / d. a gallon, but is now about d., and shows a falling tendency. make a market for this product, and the supply will be practically unlimited, as every blast furnace and coke oven in the kingdom will put up plant for the recovery of the oil, and as with the limited plant now at work it would be perfectly easy to obtain , , or , , gallons per annum, an extension of the recovery process would mean a supply sufficiently large to meet all demands. many gas managers have, from time to time, tried if they could not use some of their creosote for gas producing, but on heating it in retorts, etc., they have found the result has generally been a copious deposit of carbon, and a gas which has possessed little or no illuminating value. now, the furnace and coke oven oils are in composition somewhat akin to the creosote oil, so that at first sight it does not seem a hopeful field for search after a good carbureter, but the furnace oils have several points in which they differ from the coal tar products. in the first place, they contain a certain percentage of paraffin oil, and in the next, do not contain much naphthalene, in which the coal tar oil is especially rich, and which would be a distinct drawback to their use. the furnace oil as condensed contains about to per cent. of water, and in any case this has to be removed by distilling; and mr. staveley has patented a process by which the distillation is continued after the water has gone off, and by condensing in a fractionating column of special construction, he is able to remove all the paraffin oil, a considerable quantity of cresol, a small quantity of phenol, and about per cent. of pyridine bases, leaving the remainder of the oil in a better condition, and more valuable for pickling timber, which is its chief use. if the mixed oil so obtained, which we may call "phenoloid oil," is cracked by itself, no very striking result is obtained, the percent. of paraffin present cracking in the usual way, and yielding a certain amount of illuminants, but if this oil be cracked in the presence of carbon, and be made to pass over and through a body of carbon heated to a dull red heat, then it is converted largely into benzene, the most valuable of the illuminants, and also being the one to which coal gas owes the largest proportion of its illuminating power, it is manifestly the right one to use in order to enrich it. on cracking the phenoloid oil, the paraffins yield ethane, propane, and marsh gas, etc., in the usual way, while the phenol interacts with the carbon to form benzene-- phenol. benzene. c h ho + c = c h + co. and in the same way the cresol first breaks down to toluene in the presence of the carbon, and this in turn is broken down by the heat to benzene. a great advantage of this oil is that the flashing point is , and so is well above the limit, thus doing away with the dangers and troubles inseparable from the storage of light naphtha in bulk. in using this oil as an enricher, it must be cracked in the presence of carbon, and it is of the greatest importance that the temperature should not be too high, as the benzene is easily broken down to simpler hydrocarbons of far lower illuminating value. this fact is very clearly brought out by a series of experiments i have made, in which the phenoloid oil was cracked by passing it through an iron tube packed with coke and heated to various temperatures, the hydrocarbons being much more easily broken up under these conditions than if mixed with diluents, such as water gas: results obtained on cracking phenoloid oil. i. ii. iii. temperature. ° c. ° c. , ° c. volume of gas per gallon. . c.f. . c.f. . c.f. composition of the gas. hydrogen. . . . methane. . . . olefines. . . nil. ethane. . . nil. carbon monoxide. . . . carbon dioxide. . . . oxygen. . . nil. nitrogen. . . nil. this analysis shows that if the temperature is allowed to reach a cherry red, complete decomposition of the illuminating hydrocarbons is taking place, and a gas of practically no illuminating value results. the power of regulating the temperature and the body of carbon as a cracking medium in the van steenbergh water gas plant especially fits it for using this oil, and removes the objections which could have been urged against the lighter naphthas. this oil is at present not in the market, but given a demand, it can be produced in four months, at the latest, in very large quantities, as the apparatus is very easy and cheap to erect, and the crude material can be plentifully obtained. if this oil becomes, as i think it will, an important factor in the illumination of the future, it will mark as important an era in the history of our industries as any which the century has seen, as, by using it, you are giving smoke a commercial value, and this will do what the society of arts and the county council have failed in--that is, to give us an improved atmosphere. if i were lecturing on an imaginary "hygeia," i should point out that the smoke of london contains large quantities of these oils, and they, by coating the drops of mist on which they condense, give the fog that haunts our streets that peculiar richness which is so irritating and injurious to the system, and, further, by preventing the water from being again easily taken up by the air, prolong the duration of the fog. make this oil a marketable commodity, and another twenty years will see london without a chimney; underground shafts will be run alongside the sewers; into these shafts by means of a down draught all the products of combustion from our fires will be sucked by local pumping stations, and the oil condensing in the tubes will serve in turn to illuminate our streets, instead of performing its former function of turning day into night and ruining our health; but as i am not at all sure of the engineering possibilities of such a scheme, i will leave its discovery to some other abler prophet than myself. (_to be continued_.) * * * * * electrical laboratory for beginners. by geo. m. hopkins. it is only when theory and practice, study and experiment, go hand in hand that any true progress is made in the sciences. a head full of theory is of little value without practice, and although the student may apply himself with all his energies for years, his time will, to a great extent, have been spent in vain, unless he by experiment rivets the ideas he gains by his study. in the study of electricity, for example, let the student try to remember the position a magnetic needle will take when placed below or above a conductor carrying a current which flows in a known direction. without experiment there are nine chances of forgetting to one of remembering; but let the student try the experiment, and he will ever afterward be able to determine the direction in which the current is flowing by the position taken by the needle relative to the conductor. in the matter of ampere turns, as another example, it is quite simple to assert that a ten ampere current carried once around a soft iron bar produces the same result as a one ampere current carried ten times around the bar, but how much more strongly is this fact stamped upon the memory when its truth is established by experiment? reading about a fact, or commiting to memory the literature of a subject, is desirable and even necessary, but knowledge of this character partakes more of the nature of faith than that gained by actual experience. let the reader learn first all that can be learned by the aid of this simple apparatus, then branch out to allied things, making each step as thorough as possible, and before long he will be congratulating himself on having gained at least an elementary knowledge of electricity. very little can be done in the way of electrical experiment without an electrical generator of some sort, and nothing at present known can excel a battery for this purpose. although not the most desirable battery for all purposes, that shown in fig. is the most desirable for the amateur who desires a strong current for a short time. it is formed of two plates, a, of carbon arranged on opposite sides of an amalgamated plate, b, of zinc, and separated from the zinc by strips of wood. bars of wood are placed outside of the carbon plates, and the four bars are fastened together by two common wood screws, thus clamping all the bars and the zinc and carbon plates securely in the position of use. [illustration: fig. .--simple battery.] between the zinc plate and the wooden bar adjoining it is inserted a strip of copper, c, for leading away the current from the zinc pole of the battery, and between the carbon plates and the wooden bars is inserted a doubled strip of copper, d, forming a connection between the two carbon plates, and at the same time serving as a conductor for conveying away the current from the carbon pole of the battery. this element is to be plunged into a tumbler of sufficient depth to allow the wooden bars to rest on the upper edge of the tumbler, while the lower ends of the plates are one-half or three-quarters inch above the tumbler bottom. the solution. in the tumbler is placed a solution consisting of two-thirds of a tumblerful of water, two ounces of bichromate of potash, and two ounces of sulphuric acid. the bichromate of potash should be dissolved first, then the acid should be slowly and carefully added. as the solution heats, it is well to prepare it in an earthen vessel, which is not liable to break. these materials should be used with great caution, as they are poisonous, and the solution is very corrosive, destroying almost everything with which it comes in contact. with proper care, however, there is no danger in using the solution. it gives off no poisonous vapors. of course it is advisable to make the solution in quantities of a gallon or so when convenient. the battery compound known as the c and c battery compound, sold in tin cans at most electric stores, is very convenient. it is only necessary to place two or three ounces of it in the tumbler and add the amount of water above mentioned, stirring the solution with a glass or rubber rod until the crystals are dissolved. a caution is necessary here. if only a portion of the contents of the can are to be dissolved, it will be necessary to place the remainder in a glass or earthen jar, as it will absorb moisture and rapidly eat its way through the can. the zinc plates should be amalgamated by plunging them into the bichromate solution, then sprinkling on a minute quantity of mercury, rubbing it about by means of a swab, until the entire exposed surface is covered with mercury. conventional sign for the battery and galvanometer. in making electrical diagrams it is necessary to frequently represent a battery. it requires too much time to make a sketch or drawing of a battery. besides this, the drawing of any particular kind of battery might be misleading. a sign representing the galvanic battery has been universally adopted. it consists of a long, thin mark or dash, representing the carbon electrode, and a shorter, thick mark representing the zinc electrode, thus: [illustration] where more cells are required, this sign is repeated once for each cell, thus: [illustration] the galvanometer is represented thus: [illustration] by the use of the battery and a few articles such as may be found anywhere, in addition to the pieces shown in fig. , all the experiments here described may be performed. as these pieces are shown half size in the diagrams, fig. , and about full size in the perspective views, it will be unnecessary to give dimensions. the bobbins, a a, are wound with no. double cotton-covered magnet wire, the terminals being soldered to eyes formed of pieces of spring wire bent so as to form helical coils of two turns each, with the ends inserted in holes drilled in heads of the spools. these coiled wires answer a good purpose in making electrical connections. the magnet frame, b, consisting of the cores and the yoke formed integrally of a single soft gray iron casting, is adapted to receive the bobbins, a a, to form an electro-magnet. the yoke of the magnet is provided with a thumb-screw, e, for securing the magnet to the motor frame, c. the latter is furnished with a base piece, f, a slotted standard for receiving the clamping screw, e, of the magnet, and the standards, g, in which is journaled the armature, h, on a wire extending through both the standards and the armature. the armature, h, consists of an oblong rectangular soft iron frame having at one end a small pulley and at the other end an elliptical boss, i, which is arranged obliquely to form in conjunction with the spring, j, a circuit closer and opener, which closes the circuit twice during each revolution of the armature, just as one of its side bars is approaching the poles of the magnet and breaks it as the bar comes opposite the poles of the magnet. the spring, j, is bent into a loop and its lower end is inserted in a wooden plug driven into a hole in the base piece, f. in the upper part of fig. are shown two telegraph instruments less the bobbins. each instrument (fig. ) consists of a wooden base, k, a right angled soft iron bar, l, having the central part of its upper end brought to an obtuse angle, an armature, m, fitted loosely to the angled end of the bar, a notched brass standard, n, for limiting the movement of the armature, a retractile spring for lifting the armature, a spring key, o, pivotally secured to the base by a common wood screw, and a contact point projecting from the base under the key. besides these there is a d shaped block, to answer as a frame to the galvanometer, a common pocket compass, e, fitted to a circular cavity in the top of the block, d, a permanent u magnet, f, a bundle of soft iron wires, g, and two copper strips, h. [illustration] decomposition of water. to illustrate the decomposition of water, connect the copper strips, h h, to the poles of the battery by means of wires, as shown in fig. , and insert them in a tumbler of water acidulated with a few drops of sulphuric acid. instantly bubbles will rise from the copper strips, showing that gas is being disengaged from the water. the strip connected with the carbon plate will disengage oxygen, while the strip connected with the zinc plate will disengage hydrogen. [illustration: fig. .--decomposition of water.] solenoid. by connecting one of the coils, a, with the battery by means of the wires, the action of a helix or solenoid is shown. when so connected, the helix will draw up with itself a barrel pen, or any light iron or steel object. (see fig. .) this is not a true solenoid, but it is generally known by that name. in a true solenoid one of the terminals is passed back through the center of the coil. [illustration: fig. .--solenoid.] magnetization of steel. by inserting in the solenoid a knitting needle, or any bar of hardened or tempered steel, and sending a current through the coil, the steel will become permanently magnetized. electromagnet. by placing the two coils, a, upon the magnet frame, b, and connecting one terminal of each with the battery, the remaining terminals being connected together, as shown in fig. , an electromagnet is formed which will lift several pounds. [illustration: fig. .--electromagnet.] electric motor. by placing the magnet thus formed upon the motor base, c, in front of the armature, h, as shown in fig. , and connecting one terminal of the magnet with the battery and the other with the clamping screw, e, of the magnet, and by connecting the commutator spring, j, with the remaining pole of the battery, the motor will be made to rotate rapidly. compass and magnetic experiments. by placing one end of the bar magnetized by the solenoid near the compass contained by the cabinet (fig. ) it will be seen that one end of the compass needle is attracted. when the opposite end of the bar is presented to the same end of the needle, that end of the needle will be repelled and the opposite one attracted, showing that like poles repel each other while unlike poles attract. [illustration: fig. .--magnetic experiment.] galvanometer. by placing one of the coils, a, in the block, d, then placing in the cavity in the top of the block the compass, with the line marked n s arranged at right angles to the axis of the coil, a serviceable galvanometer will be formed (fig. ). by turning the galvanometer so that the needle will point north and south without the current passing, with n underneath one end of the needle, and then connecting the poles of the battery with the terminals of this galvanometer, a deflection of the compass needle will be produced, the direction of which depends upon the direction of the current. experiments showing the effects of resistance. by placing the galvanometer in the circuit of the battery, as shown in fig. , and noting the deflection of the needle, it will be ascertained that a certain amount of current is flowing. now, by placing in the circuit, in addition to the galvanometer, the remaining coil of the magnet, thus introducing considerable resistance, the current will be diminished, as shown by a smaller deflection of the needle. resistance of a fluid changed by the addition of another fluid. a very pretty and instructive experiment may be performed by arranging the apparatus as shown in fig. , with the copper strips, h h, inserted in clean water and the galvanometer placed in the circuit. the deflection of the galvanometer needle will be very slight, showing that the resistance of clean water is considerable. a few drops of sulphuric acid or even vinegar will increase the conductivity of the water so as to produce a marked deflection of the galvanometer needle. common salt added to the water will produce the same effect. magnetic electric induction. by placing one of the coils, a, on the magnet frame, b, and connecting it by the wires with the galvanometer, arranged as before described, and bringing the permanent magnet, f, suddenly against the poles of the magnet, as shown in fig. , a current will be induced in the coil, which, in passing through the galvanometer, causes the needle to be deflected in one direction, and when the permanent magnet is suddenly removed from the electro-magnet, a current will be set up in the opposite direction, which will cause a deflection of the needle of the galvanometer in the opposite direction. induction coil. by placing both coils, a, upon the bundle of soft iron wires, g, connecting one of them with the terminals of the battery, as shown in fig. , and holding the terminals of the other coil in the moistened thumb and fingers of the two hands, when the battery circuit is opened and closed by touching one of the wires to the battery, and removing it, a slight shock will be felt from the coil which is disconnected from the battery. by placing a coarse file in the circuit and drawing one of the terminals along the file the circuit will be rapidly interrupted. this shock is due to the current induced in the detached coil by the magnetism of the bundle of wires. [illustration: fig. .--magneto-electric induction.] extra current. an experiment showing the extra or self-induced current consists in arranging the motor as shown in fig. , and connecting wire with each conductor leading from the battery to the motor, as shown in fig. . if these wires are grasped one in each hand while the motors is in motion, a slight shock will be felt, providing the hands are moistened. telegraph sounders and keys. the cabinet contains material for two telegraph sounders and keys which will enable the user to establish a short telegraph line with a single cell of battery. the armature, m, may be lifted from its pivot so as to permit of slipping one of the coils, a, on to the round magnetic core of the sounder. the armature is then replaced, as shown in fig. , and the small retractile spring at the rear of the instrument is arranged to draw down the shorter arm of the armature lever. one of the terminals of the coil, a, is connected with the turned up pivoted end of the telegraph key, o, on the same base. the other terminal is connected with one pole of the battery and the contact point of the key is connected with the other pole of the battery, as shown. by swinging the key laterally, so as to remove it from the contact point, it will be found that every touch of the key produces a movement of the sounder lever. to connect the two instruments together upon a line, it is only necessary to connect the two keys with one wire and the terminals of the two coils with another wire, cutting one of these wires and inserting the battery. [illustration: fig. .--magnetic figures.] as soon as the operator ceases to work his instrument he should place the key in contact with the contact point, and cause it to remain there by slipping the end of the key under the head of the screw provided for that purpose. the other operator can then proceed to send his message. those who desire to practice telegraphy should learn the morse telegraphic code. magnetic figures. by arranging the coil so as to form an electro-magnet, as before described, and holding the magnet under a plate of glass sprinkled with fine iron filings, as shown in fig. , and then sending a current through the magnet, at the same time jarring the glass by striking it with a lead pencil, a magnetic figure will be formed which is sometimes called the magnetic spectrum. by connecting the terminals of the coils diagonally with each other, and connecting the remaining terminals with the battery, two like poles will be formed, and the magnetic figures will have an entirely different appearance, owing to the repulsion between the two like polarities. different figures may be produced by using the solenoids without the iron cores. experiment showing the current. by removing the coil, a, from beneath the compass, e, and connecting the ends of the transverse wire, a' a', with the battery fig. , then lifting the plates of the battery out of the solution and allowing the needle to come to rest, it will be found upon inserting the plates of the battery in the solution, very gradually, that the deflection of the needle will increase with the increase of plate surface submitted to the action of the battery fluid; and if, when the greatest deflection is reached, the coils or solenoids are introduced into the circuit, one after the other, it, will be found that each added coil diminishes the current, as will be shown by the diminished deflection of the needle. [illustration: fig. .--experiment showing the current.] microphone and telephone. take two small carbon rods, p p, if procurable, if not, use two ordinary nails, and connect them up in the circuit of the battery; lay them upon a thin box so that the rods or nails cross each other, as in fig. ; insert the electromagnet in the circuit; move the coils out a little beyond the ends of the cores, lay a thin iron plate over the ends of the coils, then jar the box upon which the bars, p p, are laid, or drop a pin upon it, or scratch it with a piece of paper, and the sound will be heard by placing the ear against the iron plate resting upon the coils of the magnet. electro metallurgy. dissolve an ounce of sulphate of copper in a half pint of water; add a few drops of sulphuric acid; connect with the zinc pole of the battery the object to be coppered. to the wire connected with the carbon attach a small plate of copper. hang the object and the copper plate in the solution a short distance apart. a deposit of copper will be quickly formed. the heating effect of the current. with a piece of very fine platinum wire (no. or ), placed in the circuit of the battery, the heating effect of the current may be shown. a half inch of no. platinum wire will serve for the experiment. if the battery is in good condition it will heat from / to / inch of the wire red hot. this is sufficient to light gas or an alcohol lamp, also to ignite powder or gun cotton. a short piece of a watch hair spring, or a piece of very fine iron wire, if placed in the circuit will be made very hot. duplication of batteries. should the experimenter desire to go more deeply into the effects of the current, he will need a more powerful battery. the battery described has been made on a very simple plan, to enable the amateur to copy it without difficulty or great expense. there is no mystery about the battery. any one can make it. all that is required is a plate of zinc, two plates of carbon, some strips of wood and copper, and two common wood screws for each cell. the tumblers may be had anywhere. although it is advisable to use insulated wire for making the electrical connections, bare wires may be used if care is taken in arranging them, so that they will not touch each other or other metallic objects which would complete the circuit. it will be found convenient if the elements of the battery are arranged upon a frame of some sort, by means of which they may be raised or lowered all together, and supported at any desired height. * * * * * the action of the silent discharge on chlorine. arguing from the fact that oxygen gas, when subjected to the silent discharge, partially undergoes condensation into ozone, it seemed possible, says mr. h.m. vernon, in the _chemical news_, that other elementary gases, as chlorine and bromine vapor, might undergo an analogous change when subjected to the same treatment. a glass tube, with a u-shaped index of fine bore glass tubing, was filled with purified and dried chlorine. after passing a current of the gas through the tube for some time, the end was sealed in the blowpipe flame. the tube was then warmed slightly, and a few bubbles of gas thus driven out. the end of the index tube dipped under strong sulphuric acid saturated with chlorine gas, so that, on cooling, a short column of the acid was drawn up. this served as an index for any changes of volume which might take place in the chlorine in the tube. a silent discharge of electricity was then passed. the volume of the gas was observed to increase slightly, but afterward it remained quite constant, even after the discharge had been passed for several hours. we may therefore conclude that no allotropic change takes place when chlorine gas is subjected to the silent discharge of electricity, the initial increase of volume being merely due to the heating effect the discharge has upon the gas. into another similar tube, filled with chlorine, was introduced a small quantity of liquid bromine. the tube thus contained chlorine saturated with bromine vapor. the silent discharge on being passed through this tube did not produce any different effect than for chlorine alone. so we may conclude that bromine vapor also does not undergo any allotropic condensation when subjected to the influence of a silent discharge of electricity. the fact that oxygen gas is capable of undergoing condensation while chlorine and bromine are not is easily explained. the oxygen atom, being divalent, is capable of uniting itself to two other atoms of oxygen or other elements, and thus with oxygen forming ozone. the atoms of chlorine and bromine, however, being only monovalent, have all their affinity satisfied when they are united to a single other atom of chlorine and bromine. it is not possible, therefore, that condensation can take place if the atoms remain monovalent. hydrogen gas and iodine vapor are in a similar manner debarred from undergoing condensation. mr. vernon, therefore, comes to the conclusion that it is most improbable that any other element but oxygen will be found capable of undergoing molecular condensation when in the gaseous state and subjected to the silent discharge. * * * * * estimating carbon in organic substances. by j. messinger. this is an improvement on the author's method of two years ago. the method is now applicable to compounds with which previously low results were obtained. the substance is weighed into a small tube mm. long and mm. wide, and is then introduced into the decomposition flask, which contains to grms. of chromic acid, care being taken that the chromic acid does not come into contact with the substance under analysis. the decomposition flask is fitted with a thistle funnel, and is connected to the reversed condenser and apparatus shown in the figure. fifty c.c. of concentrated sulphuric acid are run into the flask. during the whole of the operation a gentle current of air (free from carbon dioxide) is passed through the apparatus. the asbestos plate underneath the flask is then warmed, and thus the flask and contents are warmed by radiant heat from the plate alone until the sulphuric acid darkens. at this point, where decomposition of the organic substance begins, the flame is entirely removed. the carbon dioxide (with some carbon monoxide) passes through the condenser and then over a heated mixture of copper oxide and lead chromate contained in a tube cm. long. the gas (co ) then passes through a u-tube, in one limb of which is sulphuric acid, in the other glacial phosphoric acid. [illustration: apparatus for the estimation of carbon in organic substances.] thus dried it passes through weighed potash bulbs, after which is placed for safety a small tube containing soda lime and phosphoric acid. after the lapse of about twenty minutes, warming may be once more proceeded with in the same manner as before, and after about two and one-half hours the asbestos plate may be placed directly below the flask, and more strongly heated. the whole operation is very easily carried out, and needs no watching. with substances containing halogens, it is advisable to place, after the copper oxide tube, a small washing flask containing potassium iodide solution. * * * * * new race of dwarf dahlias. the dahlia has held a prominent place among garden flowers for many years, and it has received new life in the acquisition of a section little expected by cultivators, but peculiarly welcome. this class is the outcome of much patient work on the part of mr. t.w. girdlestone, the well known secretary of the national dahlia society, who has for some time past devoted much time to the improvement of the single varieties. we had the pleasure a short time since of receiving a photograph of this dwarf section of dahlias from messrs. j. cheal & sons, of crawley, who have purchased the stock, and this we have had engraved, as it conveys an excellent idea of the height of the plant and the profusion with which the flowers are produced. the photograph was also of interest as containing a portrait of mr. girdlestone, which we are sure will be welcome to many of our readers. the plants of this race are very dwarf, not exceeding twelve inches in height, bushy, spreading and exceedingly free in flowering, the range of varieties being at present limited to twelve. the blooms are of medium size, and the colors are distinct and rich, more particularly the scarlet and crimson shades, which can be employed to immense advantage in the flower garden. the heavy formal show varieties are of little value for planting in trim beds and borders. many of the decorative or cactus varieties are too coarse in growth to be of much value in the flower garden. therefore, this liliputian race should find favor with those who wish for showy and novel effects in the garden during the summer months. [illustration: tom thumb single dahlias.] there are no peculiarities of culture to contend with, and the unusually dwarf habit of the plants specially fits them for comparative small beds and borders. one good way would be to fill a single bed with one or more decided colors, as is now done with the tuberous begonia, for the reason that these dahlias have flowers similar in size to those of the tall-growing single varieties, and bear them on stiff stalks well above the stems. a mass of the crimson variety would produce a rich glow of color infinitely finer than a mixture of undecided hues. we anticipate a high degree of popularity for these dwarf single or tom thumb dahlias, and there is a possibility of double varieties equally dwarf which would be also welcome. the great fault of the majority of dahlias already in cultivation is the tall habit of the plants, but here we have dwarfness, a profusion of finely formed flowers, and varied and attractive colors.--_the gardeners' magazine_. * * * * * some winnebago arts. in the proceedings of the new york academy of sciences an abstract is given of a paper on the above, read by dr. frederick starr: it is well known that a tribe may have peculiarities in speech, in manners, in arts, that distinguish it at once from its neighbors. the haida carves slate as no other tribe does. the elegant blankets of mountain sheep wool from chilcat are characteristic. the hebrews tested the enemy with the word _shibboleth_, and found that he could only say _sibboleth_. a twist of the tongue in pronouncing a word is a small matter, but, small as it is, it may be perpetuated for ages. such a perpetuation of a tribal peculiarity has been aptly called an ethnic survival. some of the advanced linguists of the present day are beginning to query whether the group of modern languages of the aryan family are not examples of such ethnic survival; whether the differences between french and italian and spanish, latin, greek and slavonic, are not due to the difficulty various ancient tribes found in learning to speak the same new and foreign language. to draw an example of ethnic survival from another field of science, consider the art of the french cave men. the archæologist finds in the caverns bones of various mammals, teeth of cave bear, and antlers of reindeer carved with animal figures. the art is _good_ for a barbarous people, but it is certainly barbarian art. the range of designs is quite great: horses, bears, mammoths, reindeer, are among the figures. the people who did this work were an artistic people. to carve and represent animal forms was almost a mania with them. an ethnic impulse seems to have driven them on to such work, just as a similar impulse drives the haida slate carver to-day; just as a similar impulse has driven the bushman to cover the walls of his caves in south africa with pictures whose boldness and fidelity are the amazement of all who see them. we have, then, in the french cave dwellers a people who had a well defined art, and who, as art workers, were isolated and unlike all neighbors. an eminent english scientist believes that neither they nor their art are gone. there is a people who to-day lives much as a cave man of france lived so long ago, who hunts and fishes as he did, who dresses as he did, who builds houses in whose architecture some think they can see evidence of a cavern original, who above all still carves batons from ivory, and implements from bone, adorning them with skillfully cut figures of animals and scenes from the chase. this people is the eskimo. if dawkins' view is true, we have in the eskimo carvings of to-day a true ethnic survival--an outcropping of the same passion which displayed itself in the mammoth carving of la madelaine. scarcely anything in the range of american antiquities has caused more wonder and led to more discussion than the animal mounds of wisconsin. we do not pretend to explain their purpose. perhaps they were village guardians; perhaps tribal totems marking territorial limits; some may have been of use as game drives; some may even have served as fetich helpers in the hunt, like the prey gods of zuñi. we may never know their full meaning. it is sufficient here for me to remind you what they are and where. they are nearly confined to a belt of moderate width stretching through wisconsin and overlapping into minnesota and iowa. within this area they occur by hundreds. dr. lapham published a great work on the effigy mounds in , in which he gave the results of many accurate surveys and described many interesting localities. since his time no one has paid so much attention to the effigies as stephen d. peet, editor of the _american antiquarian_, whose articles have during this year been presented in book form. mr. peet has paid much attention to the kind of animals represented, and has, it seems to us, more nearly solved the question than any one else. he recognizes four classes of animals--land animals or quadruped mammals, always shown in profile; amphibians, always shown as sprawling, with all four feet represented; birds, recognized by their wings; and fishes, characterized by the absence of limbs of any kind. the land animals are subdivided into horned grazers and fur bearers. of the many species he claims to find, it seems to us the most satisfactorily identified are the buffalo, moose, deer, or elk; the panther, bear, fox, wolf and squirrel; the lizard and turtle; the eagle, hawk, owl, goose and crane; and fishes. one or two man mounds are known, although most of those so-called are bird mounds--either the hawk or the owl. sometimes, too, "composite mounds" are found. nor are these mounds all that are found. occasionally the same forms are found _in intaglio_, cut into the ground instead of being built above it, but just as carefully and artistically made. notice, in addition to the form of these strange earth works, that they are so skillfully done that the attitude frequently suggests action or mood. nor are they placed at random, but are more or less in harmony with their surroundings. remember, too, their great number and their large size--a man feet long, a beast feet long, with a tail measuring feet, a hawk feet in expanse of wing. they are _unique_. to be sure, there are in ohio three effigies, in georgia two, and in dakota some bowlder mosaics in animal form. none of these, however, are like the wisconsin type. the alligator and serpent of ohio are different in location and structure from the wisconsin mounds, and are of designs peculiar. the bird mound in the newark circle is more like a wisconsin effigy, but is associated with a type of works not found in the effigy region. the birds of georgia are different in conception, in material, and in build. the mosaics of dakota are simply outlines of loose bowlders. it seems to us that the effigy builders of wisconsin were a peculiar tribe, unlike their mound-building neighbors in ohio or the south; that they were a people with a passion for representing animal figures. this passion worked itself out in these earth structures. that a single tribe should be thus isolated in so remarkable a custom is no more strange than that the haida should carve slate or the bushman draw his pictures on his cavern walls. who were the effigy builders? this is a question often asked and variously answered. some writers would refer them to the winnebagoes, or, if not to them directly, to some dakota stock from which the winnebagoes have descended. formerly i was a frequent visitor to the sac and fox reservation in iowa. about of the tribe are left. to an unusual degree they retain the old dress, language, arts and dances. with them lived a few winnebagoes. in general the lives of the two peoples are similar. certain arts common to both of them particularly interested me. they are the making of sacks of barks and cords, and the weaving of bead bands for legs and arms, upon the _ci-bo-hi-kan_. of the bark sacks there are several patterns, the simplest being made of splints of bark passing alternately over and under each other. another kind, far more elaborate in construction, is before you. yet more elaborate ones are made entirely of cords. the first of these i saw was in old jennie davenport's wikiup. it was of white and black cords, and the black ones were so manipulated as to form a pattern--a line of human figures stretching across the sack. jennie would not sell it, as she said, "it is a winnebago woman's sack; fox woman not make that kind." i found afterward a large variety of these winnebago sacks, and all were characterized by patterns of men, deer, turtles, or other animals. not one fox sack of such pattern was to be found, though many elaborate and beautiful geometrical designs were shown me. the most beautiful work done on this reservation is the bead weaving on the ci-bo-hi-kan--woven work, _not_ sewed, remember. in appearance the result is like the iroquois wampum belts, but the management of the threads is dissimilar. the sac and fox patterns are frequently complex and beautiful, but always geometrical. we have seen hundreds of them, but none with life forms. the winnebago belts, made in exactly the same way, frequently, if not always, present animals or birds or human beings. this, it seems to us, is very curious. here are people of two tribes living side by side, with the same mode of life and the same arts, but in their art designs so diverse. it is a case parallel to that of the old effigy builders, a people who have a passion for depicting animal forms--a passion not shared by their neighbors. if this were the only evidence that the winnebagoes built the effigy mounds, or that their ancestors did so, it would have no great weight. but the claim has been made already on other grounds. this being the case, we think that this adds something to the testimony, and we ask, _have we here an ethnic survival?_ at the close of the paper dr. starr exhibited a number of fine specimens of indian handiwork, including woven work, bags, belts, etc. dr. newberry explained that these mounds were not sepulchral, like many others in the ohio and mississippi valleys. geologically speaking, man is very recent. the early inhabitants of america may have originally come from the east, but, if so, they were cut off from that part of the world at a very early date. the development of the tribes in america was complete and far-reaching. copper and lead mines were worked, the forests removed, and large tracts given over to the cultivation of corn, grain, etc. this was the mound age, and the constructions were certainly abandoned over one thousand years since. the pueblo indians now existing in arizona and new mexico took their origin from central america, and spread as far north as salt lake, utah, and south as far as chili. their structures were permanent stone buildings, many of which still exist in a good state of preservation. professor munroe found rocks on the ohio river, near the pennsylvania line, inscribed with figures of men, horses and other animals. at low water these figures can be distinctly observed. * * * * * the philosophy of consumption. by dr. j.s. christison, chicago. a proclamation by an eminent physician that he has discovered a specific cure for consumption in its most prevalent and insidious form, known as tuberculosis, might well create a deep and universal interest, since there are comparatively few of us that do not have this deadly enemy within the limits of our cousin kinship. and if german slaughter house statistics are to be taken as representative, no less than ten per cent. of our domesticated horned cattle are a prey to the same disease, though seldom discovered during life. this fact would suggest that tubercular consumption is still more prevalent in the human family than has yet been supposed, and that many carry it under the cover of other maladies. but unfortunately for any hope for a specific remedy, the preponderance of evidence points to the fact that consumption is much more a product of individual habits and social and climatical conditions than a resultant of any one agency. indeed, the causative evils may vary not only in their degree, but also in their number and order of action in the period of its evolution. if it were hereditary in the sense that it is transmitted by the blood as a specific germ or virus, then the offspring of consumptives would have an attenuated form of the disease, which, by reasoning from analogy, ought to secure them exemption from any further danger along that line. such, however, is not the case. but if we say a special fitness is inherited, then we can understand how the offspring of consumptives are prone to develop it, since they are not only born with hereditary qualifications, but not infrequently they are cradled amid the very agencies which fostered the evil in their parents, if, indeed, they were not primarily causative. that the contribution of heredity to consumption is great is undoubtedly the case, and, more than any other factor, it would seem to have a directing power in the army of inducing evils. but the fact that the greater number of the offspring of consumptives escape the disease, even where the general family resemblance is quite pronounced, is readily explained by the difference in personal habits, the circumstances of different periods or the domestic regulations instituted by medical counsel. also the fact that consumptives so frequently spring from neurotic parentage and the victims of dissipation, especially alcoholic, still farther goes to show that the hereditary element is essentially a reduced power of resistance to formative evils, and that as a negative condition it may hold the balance of power in focusing the forces. thus, heredity, in disease, can be understood as in no sense implying a specific force, but rather an atonic or susceptible condition, varying in its precise character and producing a _pars minoris resistentiæ_--a special weakness in a special way. that the germ _bacillus_ does not originate consumption there can be no doubt, unless consumption is not to be regarded as a disease until it is full fledged, for otherwise the germ would be present in the earlier formations, as well as the later, which, according to good authority, is not the case. but that this parasite has a special affinity for consumptive tissue there is no question, and that it thrives therein with great rapidity, hastening retrogressive changes, is also to be granted. but, as yet, this is all we are entitled to believe. we thus see that the lines of successful treatment must be both constitutional and local; that the constitutional cannot be specific, and the strictly local cannot be curative. the constitutional must be of a negative and positive character, having regard to the support of the healthy remnant, and which will require correction of any deficiency whatsoever in order to remove the morbid constitutional habit. the local will be cleansing of the affected organs from the germs and morbid products. the evident selective affinity of koch's lymph for tuberculous tissue may enable it, in certain cases, to effectually seal the arterial capillaries about the affected parts, owing to the intense vaso-motor disturbance produced. this would starve the germs, which, with the tubercular matter, may be expectorated through the moisture and motion of the lungs. in incipient cases the tubercles might be as readily absorbed as catgut ligature, and the germs, if any, fall to phagocytic prey. the koch lymph is evidently not a poison to the germs, and probably has no other action on the affected organs than that of an irritant, having a selective affinity by virtue of the kinship with its contents. this theory of its action is supported by our common knowledge of the power of pyogenic agents to awaken old or slumbering inflammations, and the fact that septic fevers, such as small-pox, have been known to leave the consumptives with the last stages free from every symptom. * * * * * the scientific american architects and builders edition. $ . a year. single copies, cts. this is a special edition of the scientific american, issued monthly--on the first day of the month. each number contains about forty large quarto pages, equal to about two hundred ordinary book pages, forming, practically, a large and splendid magazine of architecture, richly adorned with _elegant plates in colors_ and with fine engravings, illustrating the most interesting examples of modern architectural construction and allied subjects. a special feature is the presentation in each number of a variety of the latest and best plans for private residences, city and country, including those of very moderate cost as well as the more expensive. drawings in perspective and in color are given, together with full plans, specifications, costs, bills of estimate, and sheets of details. no other building paper contains so many plans, details, and specifications regularly presented as the scientific american. hundreds of dwellings have already been erected on the various plans we have issued during the past year, and many others are in process of construction. architects, builders, and owners will find this work valuable in furnishing fresh and useful suggestions. all who contemplate building or improving homes, or erecting structures of any kind, have before them in this work an almost _endless series of the latest and best examples_ from which to make selections, thus saving time and money. many other subjects, including sewerage, piping, lighting, warming, ventilating, decorating, laying out of grounds, etc., are illustrated. an extensive compendium of manufacturers' announcements is also given, in which the most reliable and approved building materials, goods, machines, tools, and appliances are described and illustrated, with addresses of the makers, etc. the fullness, richness, cheapness, and convenience of this work have won for it the largest circulation of any architectural publication in the world. a catalogue of valuable books on architecture, building, carpentry, masonry, heating, warming, lighting, ventilation, and all branches of industry pertaining to the art of building, is supplied free of charge, sent to any address. munn & co., publishers, broadway, new york. * * * * * building plans and specifications. in connection with the publication of the building edition of the scientific american, messrs. munn & co. furnish plans and specifications for buildings of every kind, including churches, schools, stores, dwellings, carriage houses, barns, etc. in this work they are assisted by able and experienced architects. full plans, details, and specifications for the various buildings illustrated in this paper can be supplied. those who contemplate building, or who wish to alter, improve, extend, or add to existing buildings, whether wings, porches, bay windows, or attic rooms, are invited to communicate with the undersigned. our work extends to all parts of the country. estimates, plans, and drawings promptly prepared. terms moderate. address munn & co., broadway, new york. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement. january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . stitched in paper, or $ . bound in stiff covers. combined rates.--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway, new york, n.y. * * * * * a new catalogue of valuable papers contained in scientific american supplement during the past ten years, sent _free of charge_ to any address. munn & co., broadway, new york. * * * * * useful engineering books manufacturers, agriculturists, chemists, engineers, mechanics, builders, men of leisure, and professional men, of all classes, need good books in the line of their respective callings. our post office department permits the transmission of books through the mails at very small cost. a comprehensive catalogue of useful books by different authors, on more than fifty different subjects, has recently been published, for free circulation, at the office of this paper. subjects classified with names of author. persons desiring a copy have only to ask for it, and it will be mailed to them. address, munn & co., broadway, new york. * * * * * patents. in connection with the scientific american, messrs. munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats, trade marks, their costs and how procured. address munn & co., broadway, new york. branch office, and f st., washington, d.c. produced from scanned images of public domain material from the google print project.) patent laws of the republic of hawaii, and rules of practice in the patent office. _fifth edition, ._ honolulu: hawaiian gazette company. . patent laws of the republic of hawaii. acts now in force. an act to regulate the issuing of patents. _be it enacted by the king and the legislative assembly of the hawaiian islands, in the legislature of the kingdom assembled_: section . all patents shall be issued in the name of his majesty the king, under the seal of the interior department, and shall be signed by the minister of interior and countersigned by the commissioner of patents, and they shall be recorded together with the specifications in the office of the interior department in books kept for the purpose. section . every patent shall contain a short title or description of the invention or discovery, correctly indicating its nature and design, and a grant to the patentee, his heirs or assigns for the term of ten[a] years, of the exclusive right to make, use and vend the invention or discovery throughout the hawaiian islands, referring to the specification for the particulars thereof. a copy of the specifications and drawings shall be annexed to the patent and be a part thereof. section . any person who has invented or discovered any new and useful art, machine, manufacture, process or composition of matter, or any new and useful improvement thereof not known or used by others in this country, and not patented (or described in any printed publication) in this or any foreign country before his invention or discovery thereof, may, upon payment of the fees required by law, and other due proceedings had, obtain a patent therefor. provided, however, that any person who has invented or discovered any new and useful art, machine, manufacture, process or composition of matter, or any new and useful improvement thereof, and has received a patent or patents therefor from any foreign government may also obtain a patent therefor in this country as provided above, unless the thing patented has been introduced into public use in the hawaiian islands for more than one year prior to the application for a patent. but every patent granted for an invention which has been previously patented in a foreign country, shall be so limited that it shall not continue longer than the time of the expiration of such foreign patent, or if there are several foreign patents, it shall not continue longer than the time of the expiration of the one with the shortest unexpired term, and in no case shall it be in force more than ten[a] years. section . before any inventor or discoverer shall receive a patent for his invention or discovery he shall apply therefor in writing to the minister of interior, and shall file in the office of the interior department a written description of the same and of the manner and process of making, compounding and using it, in clear, concise and exact terms and in case of a machine he shall explain the principle thereof and of the manner in which he has applied that principle so as to distinguish it from other inventions, and he shall particularly point out and distinctly claim the part, improvement or combination which he claims as his invention or discovery. when the nature of the case admits of drawings the applicant shall furnish them as set forth in section . when the invention or discovery is of a composition of matter, the applicant shall furnish a specimen of ingredients and of the composition, sufficient in quantity for the purpose of experiment. in all cases which admit of representation by model, the applicant shall, if required, furnish a model of convenient size to exhibit advantageously the several parts of his invention. section . the applicant shall make oath that he believes himself to be the original and first inventor or discoverer of the art, machine, manufacture, composition or improvement for which he solicits a patent, and that, he does not know or believe that the same was ever before known or used, and shall state of what country he is a citizen. section . on filing of any such application and the payment of the fees required by law, the commissioner of patents shall examine the alleged new invention or discovery, and if upon such examination it shall appear that the claimant is justly entitled to a patent under the law and that the same is sufficiently useful and important, he shall report accordingly to the minister of interior, who shall cause a patent to be issued therefor. section . any person who makes any new invention or discovery, and desires further time to mature the same, may on payment of the fees required by law, file in the interior department a _caveat_ setting forth the design thereof and its distinguishing characteristics, and praying protection of his right until he shall have matured the invention. such _caveat_ shall be preserved in secrecy and shall be operative for the term of one year from the filing thereof. section . the commissioner of patents shall be appointed by the minister of interior and shall examine and report on all applications for patents and shall receive for such services a fee of twenty dollars for each application examined and reported by him, which fee shall be paid by the applicant in advance. in addition to this fee the following fees shall be charged all applicants for patents, upon filing each original application for a patent, five dollars; and upon issuing a patent, five dollars; and five dollars shall be charged for the filing of a _caveat_. section . this act shall take effect and become a law from and after its publication, and "an act to amend section and of the civil code, and add a new section to the civil code to be numbered section a," approved the twenty-second day of june, a. d. , is hereby repealed. approved this twenty-ninth day of august, a. d. . kalakaua rex. [a] amended to read "fifteen." act , laws of . an act to amend an act to regulate the issuing of patents, approved the twenty-ninth day of august, . _be it enacted by the king and the legislature of the hawaiian kingdom_: section . that the said act shall be amended by the addition thereto of five new sections, to be numbered sections , , , and , to read as follows: "section . the commissioner of patents is hereby authorized to administer oaths for all purposes connected with the business of his office. "section . if, upon the examination of any application for a patent, the commissioner of patents shall make a report adverse to the applicant, he shall furnish to the applicant, or his attorney, a written statement of his reasons for such report, and the applicant may thereupon amend his application, or, within ninety days thereafter, may appeal to the supreme court in banco; and, if such appeal shall be made, said applicant shall file in the office of the minister of the interior, at least twenty days before the hearing by said court, his reasons for appeal, specifically set forth in writing, and give to the said minister of the interior at least ten days' notice of the time and place of such hearing. "section . the court shall hear and determine such appeal, and shall file in the office of the minister of the interior a certificate of its decision, and such decision shall determine the further proceedings in the case. "if such decision be in favor of the applicant, the minister of the interior shall cause to be issued the patent applied for, or such modification thereof as shall be decided by said court. "section . damages for the infringement of any patent may be recovered, by action on the case, in the supreme court, in the name of the party interested. and the party aggrieved shall also have his remedy, according to the course of equity, to enjoin such infringement, and to recover compensation therefor. "section . the term infringement, as used in this act, is defined to mean the making, using or vending of any patented article without the written consent of the owner of the patent thereon, or of his agent, authorized to grant such consent." section . this act shall take effect from and after the date of its approval. approved this twenty-third day of june, a. d. . kalakaua rex. by the king: l. a. thurston, minister of the interior. act . an act to amend sections and of an act entitled "an act to regulate the issuing of patents," approved august , , and to add two new sections to said act, as amended by an act entitled "an act to amend an act regulating the issuing of patents," approved the rd day of june, , to be called sections and . _be it enacted by the legislature of the republic of hawaii:_ section . that section of an act entitled "an act to regulate the issuing of patents," approved august , , is hereby amended by striking out the word "ten" and inserting in its place the word "fifteen," so that said section as amended shall read as follows: "section . every patent shall contain a short title or description of the invention or discovery, correctly indicating its nature and design, and a grant to the patentee, his heirs or assigns, for the term of fifteen years, of the exclusive right to make, use and vend the invention or discovery throughout the hawaiian islands, referring to the specifications for the particulars thereof. a copy of the specifications and drawings shall be annexed to the patent and be a part thereof:" section . that section of an act entitled "an act to regulate the issuing of patents," approved august , , is hereby amended by striking out the word "ten" and inserting in its place the word "fifteen," so that said section as amended shall read as follows: "section . any person who has invented or discovered any new and useful art, machine, manufacture, process or composition of matter, or any new and useful improvement thereof not known or used by others in this country, and not patented (or described in any printed publication) in this or any foreign country before his invention or discovery thereof, may, upon payment of the fees required by law, and other due proceedings had, obtain a patent therefor. provided, however, that any person who has invented or discovered any new and useful art, machine, manufacture, process or composition of matter, or any new and useful improvement thereof, and has received a patent or patents therefor from any foreign government, may also obtain a patent therefor in this country as provided above, unless the thing patented has been introduced into public use in the hawaiian islands for more than one year prior to the application for a patent. but every patent granted for an invention which has been previously patented in a foreign country, shall be so limited that it shall not continue longer than the time of the expiration of such foreign patent, or if there are several foreign patents, it shall not continue longer than the time of the expiration of the one with the shortest unexpired term, and in no case shall it be in force more than fifteen years." section . that a new section to said act, as amended by the act entitled "an act to amend an act to regulate the issuing of patents," approved june rd, , be added, to be called section . "section . whenever any patent is inoperative or invalid, by reason of a defective or insufficient specification, or by reason of the patentee claiming as his own invention or discovery more than he had a right to claim as new, if the error has arisen by inadvertance, accident or mistake, and without any fraudulent or deceptive intention, the minister of the interior shall, on the surrender of such patent and the payment of the same fees required by law upon the issue of an original or first patent, cause a new patent for the same invention, and in accordance with the corrected specification, to be issued to the patentee, or, in the case of his death, or of an assignment of the whole or any undivided part of the original patent, then to his executors, administrators, or assigns, for the unexpired part of the term of the original patent. such surrender shall take effect upon the issue of the amended patent. the minister of the interior may, in his discretion, upon demand of the applicant, and upon payment of the same or first fee required to be paid on the issuing of a patent, cause several patents to be issued for distinct and separate parts of the thing patented. the specifications and claim in every such case shall be subject to revision and restriction in the same manner as original applications are. every patent so re-issued, together with the corrected specification, shall have the same effect and operation in law, on the trial of all actions for causes thereafter arising, as if the same had been originally filed in such corrected form; but no new matter shall be introduced into the specification, nor in case of a machine patent shall the model or drawings be amended, except each by the other, but when there is neither model nor drawing, amendments may be made upon proof satisfactory to the minister of the interior, that such new matter or amendment was a part of the original invention, and was omitted from the specification by inadvertance, accident, or mistake, as aforesaid. upon the filing of any such application for a re-issue with the minister of the interior, the same examination shall be had as is provided by section of the "act to regulate the issuing of patents," approved august th, ." section . that a new section to said act, as amended by the act entitled "an act to amend an act to regulate the issuing of patents," approved june rd, , be added, to be called section . "section . patents may be granted and issued and re-issued to the assignee of the inventor or discoverer, but the assignment must first be filed in the office of the minister of the interior. and in all cases of an application by an assignee for the issue of a patent, the application shall be made, and the specification signed as provided by law by the inventor or discoverer. and in all cases of an application for a re-issue of any patent, the application must be made, and the corrected specification signed by the inventor or discoverer, if he is living." section . this act shall take effect from the date of its approval. approved this th day of may, a. d. . sanford b. dole, president of the republic of hawaii. an act to provide for the registration of copyrights. _be it enacted by the king and the legislature of the hawaiian kingdom_: section . that from and after the date of the passage of this act the author of any map, book, chart, musical composition, print, cut, engraving, photograph, painting, drawing or statue, or the author of any model, or design, intended to be perfected and completed as a work of the fine arts, or the heirs, executors or administrators of a deceased author thereof, may procure a certificate of copyright therefor in the manner hereinafter provided. section . before anyone shall receive a certificate of copyright, an application therefor shall be filed in the office of the minister of the interior, verified by oath of the applicant, that such applicant is the original and first author of the map, book, chart, musical composition, print, cut, engraving, photograph, painting, drawing, statue, model or design, intended to be perfected and completed as a work of the fine arts, upon which a certificate of copyright is applied for, or if such application shall be made by the legal representative of a deceased author, such representative shall make oath that he believes that the said deceased author was the original and first author of the said map, book, chart, musical composition, print, cut, engraving, photograph, painting, drawing or statue, or the model or design intended to be perfected and completed as a work of the fine arts, and such applicant shall state of what country he is a citizen. such application shall be accompanied by said oath, and by a copy of the said map, book, chart, musical composition, print, cut, engraving, photograph, painting, drawing, or statue, or the model or design intended to be perfected and completed as a work of the fine arts, if the same shall have been published, or, if the same shall not have been published, a copy of the title thereof. all such copies shall be preserved in the department of the interior, and all such titles shall be recorded in a book, to be kept for that purpose, in said department. if the said map, book, chart, musical composition, print, cut, engraving, photograph, painting, drawing, or statue, or, if the said model or design, intended to be perfected and completed as a work of the fine arts, shall not have been published at the time of filing said application, the person or persons making said application shall, in order to the validity of the certificate of copyright, provided in section of this act, deliver or cause to be delivered to the minister of the interior, a copy of such map, book, chart, musical composition, print, cut, engraving, photograph, painting, drawing, or statue, or of the model or design intended to be perfected and completed as a work of the fine arts, within one month after the publication thereof in this kingdom. section . upon filing such application the applicant shall pay to the minister of the interior a fee of five dollars. section . upon the filing of such application so accompanied, and the payment of such fee, the minister of the interior shall cause to be issued to the applicant a certificate of copyright, under the seal of the department of the interior, granting to him and to his heirs, executors, administrators and assigns the exclusive right to print, re-print, publish, use and vend the said map, book, chart, musical composition, print, cut, engraving, photograph, painting, drawing, or statue, or the said model or design intended to be perfected and completed as a work of the fine arts, throughout the hawaiian kingdom, for the term of twenty years from the date thereof. section . no person shall maintain an action for the infringement of his copyright, unless he shall give notice thereof by inserting in each copy of his map, book, chart, musical composition, print, cut, engraving, photograph, painting, drawing, or statue, or in his model or design, intended to be perfected and completed as a work of the fine arts, on the title page, or on the page immediately following it, if it be a book, or if a map, chart, musical composition, print, cut, engraving, photograph, painting, drawing or statue, or model or design intended to be perfected and completed as a work of the fine arts, by inscribing upon some visible portion thereof, or of the substance on which the same shall be mounted, the words "_hawaiian copyright_," and the name of the person to whom the certificate of copyright was issued, and its date, thus: "_hawaiian copyright by a. b., june , ._" section . in the construction of this act the words "print," "cut," and "engraving," shall be applied only to pictorial illustrations, or works connected with the fine arts, and no prints or labels designed to be used for any other articles of manufacture shall be certified under the copyright law. section . an act entitled "an act to encourage learning in this kingdom by securing the copies of charts, maps and books to the authors and proprietors of such copies," approved the thirty-first day of december, , and all other laws, and parts of laws, in conflict with the provisions of this act, are hereby repealed. section . this act shall take effect from and after the date of its approval. approved this twenty-third day of june, a. d. . kalakaua rex. by the king: l. a. thurston, minister of the interior. an act to provide for the registration of prints, labels and trade marks. _be it enacted by the king and the legislature of the hawaiian kingdom_: section . any person or firm or any corporation desiring to secure the exclusive use of any print, label or trade mark intended to be attached or applied to any goods or manufactured articles, or to bottles, boxes or packages containing such goods or manufactured articles to indicate the name of the manufacturer, the contents of the packages, the quality of the goods or directions for use, may obtain a certificate of the registration of such print, label or trade mark in the manner hereinafter provided. section . before anyone shall receive a certificate of the registration of a print, label or trade mark, he shall file in the office of the minister of the interior an application for the registration of such print, label or trade mark with a declaration verified by the oath of the applicant; or if the application be made by a firm or a corporation, by the oath of a member of such firm, or an officer of such corporation, that he is or they are the sole or original proprietor or proprietors, or the assign or assigns of such proprietor or proprietors of the goods or manufactured articles for which such print, label or trade mark is to be used, and describing such goods and manufactured articles, and the manner in which such print, label or trade mark is to be used. said application shall be accompanied by two[b] exact copies of such print, label or trade mark. section . upon filing such application, the applicant or applicants shall pay to the minister of the interior a fee of five dollars. section . upon receiving such application so accompanied, and the payment of such fee, the minister of the interior shall cause the said print, label or trade mark to be recorded in a book to be kept for that purpose, and shall issue to the applicant or applicants a certificate of registration under the seal of the department of the interior; and such certificate of registration shall secure to the applicant or applicants the exclusive use of the said print, label or trade mark throughout the hawaiian islands for the term of twenty years from the date thereof. section . this act shall take effect from and after the date of its approval. approved this twenty-third day of june, a. d. . kalakaua rex. by the king: l. a. thurston, minister of the interior. [b] note.--it has been found in practice that three copies are necessary; one is filed with the application and oath, one is attached to the record, and one is attached to the certificate when issued. rules of practice in the patent office of the republic of hawaii. the following regulations, designed to be in strict accordance with the laws of the hawaiian islands, relating to the granting of patents for inventions, and the registration of copyrights, prints, labels and trade marks, are published for the guidance of all persons interested. the observance of the appended forms in all cases to which they may be applicable is recommended to inventors and attorneys. c. b. ripley, _commissioner of patents._ approved: j. a. king, minister of the interior. correspondence. --all business with the office should be transacted in writing. all action of the office will be based exclusively on the written record. --all letters must be addressed to the minister of the interior. --freight, postage or other charges on matter sent to the office must be prepaid in full. otherwise it will not be received. --the correspondence of the office will be held with the applicant, unless he shall have appointed an attorney to represent him, or unless he shall have assigned the entire interest of his invention, in either of which cases the correspondence will be held with such attorney or such assignee. --a separate letter, should in every case, be written in relation to each distinct subject of inquiry or application. information to correspondents. --the office cannot respond to inquiries as to the novelty of an alleged invention in advance of an application for a patent. --_caveats_, and pending applications, are preserved in secrecy. no information will be given respecting the filing of any _caveat_ or application for a patent without authority from the applicant, unless it shall be necessary to the proper conduct of business before the office. --after a patent has been issued, the model, specification and drawings are subject to general inspection, and copies, except of the model, will be furnished on the terms published with these rules. attorneys. --any person of intelligence and good moral character, may appear as the agent or the attorney-in-fact of an applicant upon filing a proper power of attorney. --powers of attorney may be revoked at any stage of the proceedings in a case; and when so revoked, the office will communicate directly with the applicant or such other attorney as he may appoint. the assignee of the entire interest may be represented by an attorney of his own selection. applicants. --any person who has invented or discovered any new and useful art, machine, manufacture, process or composition of matter, or any new or useful improvement thereof, not known or used by others in this country, or described in any printed publication before his invention or discovery thereof, may upon payment of the fees required by law and other due proceedings had, obtain a patent therefor. provided, also, that if such person has received a patent or patents for his invention or discovery from any foreign government, he may also obtain a patent therefor in this country, unless the article patented has been introduced into public use in the hawaiian islands for more than one year prior to his application for a patent. --in case of the invention or discovery having been previously patented in a foreign country, the patent issued in this country shall be so limited that it shall not continue longer than the time of the expiration of such foreign patent, or if there is more than one foreign patent it shall not continue longer than the time of the expiration of the one with the shortest unexpired term, and in no case shall it be in force more than ten years. the application. --applications for letters patent must be made to the minister of the interior in writing. --a complete application comprises the petition, specification, oath and drawings, and the model or specimen when required, and the first fee of twenty-five dollars. the petition, specification and oath must be written in the english or the hawaiian language. --no application for a patent will be placed upon the files for examination until all of its parts except the model or specimen are received. the petition. --the petition is a communication duly signed by the applicant, and addressed to the minister of the interior, stating the name and residence of the petitioner, and requesting the grant of a patent for the invention therein designated by name, with a reference to the specification for a full disclosure thereof. the specification. --the specification is a written description of the invention or discovery, and of the manner and process of making, constructing, compounding and using the same, and is required to be in such full, clear, concise and exact terms as to enable any person skilled in the art or science to which it appertains, or with which it is most nearly connected, to make, construct, compound and use the same. it must conclude with a specific and distinct claim or claims of the part, improvement or combination which the applicant regards as his invention or discovery. --the following order of arrangement should be observed in framing the specifications: first--preamble, giving the name and residence of the applicant and the title of the invention; second--general statement of the object and nature of the invention; third--brief description of the drawings, showing what each view represents; fourth--detailed description explaining fully the alleged invention, and the manner of constructing, practicing, operating and using it; fifth--claim or claims; sixth--signature of the inventor; seventh--signature of two witnesses. --where there are drawings the description will refer by figures to the different views, and by letters or figures to the different parts. --the specification must be signed by the inventor or his attorney, and the signature must be attested by two witnesses. full names must be given, and all names, whether of applicants or witnesses, must be legibly written. --all of the papers must be written in a fair, legible hand, on but one side of the paper, otherwise the office may require them to be printed. all interlineations and erasures must be clearly marked in marginal or foot notes, written on the same page. legal cap paper, with the lines numbered, is preferable, and a wide margin must be reserved upon the left hand side of each page of the specification. the oath. --the inventor must make oath that he does verily believe himself to be the original and first inventor or discoverer of the art, machine, manufacture, composition or improvement for which he solicits a patent. that the same has not been patented to himself or others with his knowledge or consent in any foreign country, or if the same has been so patented, the details of, name, country, date, number and term must be given; and that the same has not to his knowledge been introduced into public use in the hawaiian islands for more than one year; that he does not know or believe that the same was ever before known or used, and shall state of what country he is a citizen, and his place of residence. --the oath may be made before any person within this republic authorized by law to administer oaths, or when the applicant resides in any foreign country, before any minister, charge d'affaires, consul or commercial agent, holding commission under the hawaiian government, or before any notary public in such foreign country, the oath being attested in all cases by the proper official seal of the officer before whom oath is made. when the oath is sworn before any official abroad, other than a hawaiian consul or agent, a certificate as to the authority of such official must be obtained from such consul or agent under his official seal and annexed thereto. drawings. --the applicant for a patent is required by law to furnish drawings of his invention where the nature of the case admits of it. --the drawings must be signed by the inventor, or his attorney, and attested by two witnesses, and must show every feature of the invention covered by claims. --the drawings to be in duplicate, one copy on heavy parchment, the other copy on tracing cloth, the drawings to be made with india ink of best quality and with pen only, every line and letter must be black. the size of a sheet on which a drawing is made should be exactly Ã� inches, one inch from its edges a single marginal line to be drawn, leaving the "sight" Ã� inches. within this margin all work and signatures must be included, one of the smaller sides of the sheet is regarded as its top, and measuring downward from the marginal line a space of not less than - / inches is to be left blank for the insertion of title, name, number and date. --the scale to which a drawing is made should be large enough to show the mechanism without crowding, and more than one sheet may be used, if necessary, to accomplish this end. letters and figures of reference should be carefully formed, and large enough to be plainly distinguished. if the same part of the invention appears in more than one view of the drawing, it must always be represented by the same character; and the same character must never be used to designate different parts. --no agent's or attorney's stamp, or advertisement, or written address, will be permitted upon a drawing. should the application be found incomplete under the above rules and be returned from the minister of the interior for amendment, the same must be again filed within thirty days, if the applicant is a resident of the hawaiian islands, or within four months if residing in a foreign country; otherwise it will be barred, if interfering with another application filed during the interval and covering the same invention or improvement. the model. --a model will not be required as part of the application unless on examination of the case it shall be found to be necessary or useful; when, if so found, the commissioner of patents shall, in writing, notify the applicant, and action in the case shall be suspended until a model is furnished. --the model must clearly exhibit every feature of the machine which forms the subject of a claim of invention, but should not include other matter than that covered by the actual invention or improvement, unless it shall be necessary to the exhibition of the invention in a working model. --the model must be neatly and substantially made of durable material, metal being deemed preferable; but when a material forms an essential feature of the invention, the model will be constructed of that material. --the model must not be more than one foot in length, width or height, unless the commissioner of patents shall admit working models of complicated machines of larger dimensions. --models belonging to patented cases will not be taken from the office except in the custody of a sworn employee especially authorized by the commissioner of patents. specimens. --when the invention or discovery is of a composition of matter the applicant shall furnish a specimen of the composition and of its ingredients sufficient in quantity for the purpose of experiment. --in all cases where the article is not perishable a specimen of the composition claimed, put up in proper form to be preserved in the office must be furnished. interferences. --an interference is a proceeding instituted for the purpose of determining the question of priority of invention between two or more parties claiming substantially the same patentable invention or discovery. --if an application filed appears to claim substantially the same invention for which a _caveat_ has been filed, the commissioner of patents will notify the caveator to complete his application in three months, and if upon the filing thereof it appears to be in conflict an interference will be declared. if the caveator fails to complete his application within the time designated, or such further time as for cause shown may be granted to him, the commissioner of patents will proceed to examine the first named application as if there were no _caveat_. --each party to the interference will be required to file a concise statement under oath showing the date of his original conception of the invention, of illustration by drawing or model, of its disclosure to others of its completion and of the extent of its use. --testimony in such cases may be taken orally before the commissioner of patents, at such time as he may designate, or it may be taken by commission according to the forms usual in the courts of the republic. --after the testimony is closed the case shall be carefully examined by the commissioner of patents and adjudicated upon the proofs presented. caveats. --a _caveat_ under the patent law is a notice given to the office of the caveator's claim as inventor, in order to prevent the grant of a patent to another for the same alleged invention upon an application filed during the life of the _caveat_, without notice to the caveator. --a _caveat_ may be filed in the interior department by any person who has made any new invention or discovery, and desires further time to mature the same, upon payment of the fee required by law. such _caveat_ shall be preserved in secrecy, and shall be operative for the term of one year from the date of filing. --the _caveat_ must comprise a petition, a specification, an oath, and when the nature of the case admits of it, a drawing, and must be limited to a single invention or improvement. the attest of oath must comply with rule . appeals. --appeal from an adverse report of the commissioner of patents lies to the supreme court in banco. the commissioner of patents will furnish, through the minister of the interior, to the applicant or to his attorney, a written statement of his reasons for such report, whereupon the applicant may amend his application or may, within ninety days after such written statement is furnished to him or to his attorney, or mailed in the post-office at honolulu, addressed to him or to his attorney, appeal to the supreme court in banco. in case of appeal the applicant shall file in the office of the minister of the interior at least twenty days before the hearing by said court, his reasons for appeal specifically set forth in writing, and shall give to said minister at least ten days' notice in writing of the time and place of such hearing. copyright. --a certificate of copyright may be procured by the author of any map, book, chart, musical composition, print, cut, engraving, photograph, painting, drawing or statue, or the author of any model or design intended to be perfected and completed as a work of the fine arts, or by the heirs, executors or administrators of a deceased author thereof. the words "print," "cut," and "engraving," shall be applied only to pictorial illustrations or works connected with the fine arts, and no print or label designed to be used for other articles of manufacture shall be certified under the copyright law. application for copyright. --the application for a certificate of copyright is a communication signed by the applicant and addressed to the minister of the interior, stating that such applicant is the original and first author of the article upon which a certificate of copyright is applied for, and of what country he is a citizen. if application be made by the representative of a deceased author, such applicant shall state that he is the heir, executor or administrator (as the case may be) of such deceased author, that he believes that said deceased author was the original and first author of the article upon which a certificate of copyright is applied for, and of what country he--such representative--is a citizen. such statement shall be verified by the oath of the applicant, and accompanied by a copy of the article upon which a certificate of copyright is applied for, if the same shall have been published; or, if the same shall not have been published, a copy of the title thereof. in case such article shall not have been published at the time of filing the application, a copy thereof shall be delivered to the minister of the interior within one month after the publication thereof in this republic. the duration of a copyright is twenty years. the attest of oath must comply with rule . prints, labels and trade-marks. --a certificate of the registration of any print, label or trade-mark intended to be attached or applied to any goods or manufactured articles, or to bottles, boxes or packages containing the same to indicate the name of the manufacturer, the contents of the packages, the quality of the goods, or directions for use, may be secured by any person, firm or corporation. application for the registration of a print, label or trade-mark. --the application for a certificate of registration for a print, label or trade-mark is a declaration signed by the applicant or applicants and addressed to the minister of the interior, stating that such applicant is, or such applicants are, the sole and original proprietor or proprietors, or the assign or assigns, of such proprietor or proprietors of the goods or manufactured articles for which such print, label or trade-mark is to be used, and describing such goods and manufactured articles and the manner in which such print, label or trade-mark is to be used. such declaration shall be verified by the oath of the applicant; or, if the application be made by a firm or a corporation, by the oath of a member of such firm or an officer of such corporation, and accompanied by three[c] exact copies of such print, label or trade-mark. the duration of the registration of a print, label or trade-mark is twenty years. the attest of oath must comply with rule . assignments. --every patent, every certificate of copyright and every certificate of registration of a print, label or trade-mark, or interest therein, shall be assignable in law by an instrument in writing; and the patentee, or his assigns, or legal representatives may, in like manner, grant and convey an exclusive right under his patent, or his certificate of resignation, to the whole or any specified part of the hawaiian republic. such assignments must be executed and acknowledged in the same manner which is prescribed by law for conveyances of real property, and must be filed for record (in the office of the registrar of conveyances) within three months after execution. fees. --on filing an application for a patent $ on filing a _caveat_ on filing an application for copyright on filing an application for print, label or trademark on the issue of a patent for copies of records, for every one hundred words, or fraction thereof for translation of every one hundred words, or fraction thereof for copies of drawings, the cost of making them for revenue stamp on each patent for recording every assignment, for every one hundred words, or fraction thereof [c] note.--the law calls for two exact copies of the print, label or trade-mark, but in practice it is found that three are necessary. forms. no. .--petition for a patent. to the minister of the interior: your petitioner,----, a citizen (or subject) of----, residing at----, prays that letters patent be granted to him for the improvement in----, set forth in the annexed specification. (_signature of applicant._) no. .--caveat. to the minister of the interior: the petition of----, a citizen (or subject) of----, residing at----, represents that he has made certain improvements in----, and desires further time to mature the same. he, therefore, prays the protection of his right until he shall have matured his invention, and that the subjoined description thereof may be filed as a _caveat_, in the confidential archives of the office, and preserved in secrecy. (_signature of applicant._) no. .--oath for patent or caveat. hawaiian islands, } _ss._ _island of_ --------} ----, the above named petitioner, residing at----, being duly sworn, deposes and says, that he verily believes himself to be the original, first and sole inventor of the improvement in----, described and claimed in the foregoing specification; that the same has not been patented to himself or to others, with his knowledge or consent, except in the following countries:---- -------------------------------------------------- country. | no. | date of patent. | term of years. ---------|-----|-----------------|---------------- | | | .........|.....|.................|................ | | | .........|.....|.................|................ | | | .........|.....|.................|................ -------------------------------------------------- that the same has not, to his knowledge, been introduced into public use in the hawaiian islands for more than one year prior to his application for a patent; and he does not know or believe that the same was ever before known or used; and that he is a citizen (or subject) of----. (_inventor's full name._) sworn to and subscribed before me, this ---- day of ----, a. d. --. [l. s.] (_signature of notary._) (see rule .) no. .--petition for certificate of copyright by an author. to the minister of the interior: your petitioner,----, a citizen (or subject) of----, residing at----, prays that a certificate of copyright be issued to him for---- (describe the article)---- a copy whereof is filed herewith. (_author's full name._) no. .--oath of applicant for certificate of copyright. hawaiian islands, } _ss._ _island of_ --------} ----, the above named petitioner, residing at----, being duly sworn, deposes and says, that he is the original and first author of---- (describe the article)---- in the foregoing petition mentioned, and that he is a citizen (or subject) of----. (_author's full name._) sworn to and subscribed before me, this ---- day of ----, a. d. --. [l. s.] (_signature of notary._) (see rule .) no. .--petition for certificate of copyright by the representative of a deceased author. to the minister of the interior: your petitioner,----, a citizen (or subject) of----, residing at----, prays that a certificate of copyright be issued to him as the (heir, executor or administrator) of----, deceased, for----, (describe the article)----, a copy whereof is filed herewith. (_signature of petitioner._) no. .--oath of applicant for certificate of copyright on the work of a deceased author. hawaiian islands, } _ss._ _island of_ --------} ----, the above named petitioner, residing at----, being duly sworn, deposes and says, that he is the (heir, executor or administrator) of----, deceased, that he verily believes that the said----, deceased, was the original and first author of---- (describe the article)----, in the foregoing petition mentioned; and that he is a citizen (or subject) of----. (_petitioner's full name._) sworn to and subscribed before me, this ---- day of ----, a. d. --. [l. s.] (_signature of notary._) (see rule .) no. .--petition for certificate of registration of print, label or trade-mark. to the minister of the interior: your petitioner,----, a citizen (or subject) of----, residing at----, prays that a certificate of registration of the----, (print, label or trade-mark, as the case may be), three copies whereof are filed herewith, be issued to (name of person, firm or corporation.) (_signature of petitioner._) no. .--oath of applicant for certificate of registration of print, label or trade-mark. hawaiian islands, } _ss._ _island of_ --------} ----, residing at----, being duly sworn, deposes and says, that he is the petitioner in the foregoing petition named, and is (a member of the firm of----, or the---- kind of officer----, of----, name of corporation----), that he is (or they are) the sole and original proprietor (or proprietors) (or the assign or assigns) of----, name of the original proprietor or proprietors----, of the----, (describe the goods or manufactured articles for which the print, label or trade-mark is to be used) and that the said (print, label or trade-mark) is to be used in the following manner, to wit: (describe the method of using.) (_signature of petitioner._) sworn to and subscribed before me, this ---- day of ----, a. d. --. [l. s.] (_signature of notary._) (see rule .) index. rule. no. administrators and executors , adverse reports affidavits amendments appeals applicants , application for patent to application for copyright application for print, label or trade-mark assignee , , , assignments attorneys , caveats , , to claims , composition of matter , , copies , copyright law page copyrights, duration of copyrights, who may procure , correspondence to correspondents, information to to depositions drawings to duration of copyright duration of patent duration of print, label or trade-mark evidence , examination , , executors , fees foreign patents , , freight and charges hearing, notice of information to correspondents to interferences to label, duration of label, registration of , language models , , to notice , , oath before whom taken oath to copyright oath to patent , oath to print, label or trade-mark patent, duration of patent laws pages to patent, who may obtain petition for copyright petition for patent petition for print, label or trade-mark postage power of attorney , previous foreign patent print, duration of print, label and trade-mark law pages and print, registration of , priority of invention reasons for adverse report record of assignments record, subject to general inspection re-examination removal of models revocation of power of attorney signatures , , , specifications , to specimens , , substitution of attorney supreme court, appeal to testimony , trade-mark, duration of trade-mark, registration of , translation, (see fees) index to forms. form. page. petition for patent caveat oath for patent or caveat petition for copyright by author oath to petition for copyright by author petition for copyright by representative of a deceased author oath to application for copyright on work of a deceased author petition for registration of print, label or trade-mark oath of applicant for registration of print, label or trade-mark distibuted proofreaders [illustration] scientific american supplement no. new york, september , scientific american supplement. vol. xviii, no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. chemistry and metallurgy.--gallisin, an unfermentable substance in starch sugar. the combining weights, volumes, and specific gravities of elements and compounds. analysis of zinc ash and calcined pyrites by means of ammonium carbonate. ii. engineering and mechanics.--petroleum as a fuel in locomotive engines.--by thomas urquhart.--spray injector.--driving locomotives.--storage of petroleum. improved gas light buoy.-- figures. project for a roadstead at havre.--with map and views of different breakwaters. improved catch basin.-- figures. water power with high pressures and wrought iron water pipe.--by hamilton smith, jr.--methods of conducting water and transmitting power.--texas creek pipe and aqueduct.-- figures. parachute hydraulic motor. improved shafting lathe.-- figure. power straightening machine.-- figure. hydraulic mining in california.--by geo. o'brien. iii. technology.--emerald green: its properties and manufacture.--use in wall paper.--robert galloway. charcoal kilns.--extra yield.-- figures. iv. architecture--entrance, tiddington house, oxon.--an engraving. v. electricity, light, heat. etc.--the temperature of the earth as shown by deep mines. new arrangement of the bichromate of potash pile.-- figures. the distribution of electricity by induction.-- figure. electricity applied to the study of seismic movements.--apparatus for the study of horizontal and vertical seismic movements, etc.-- figures. new accumulators.-- figures. industrial model of the reynier zinc accumulator. the history of a lightning flash.--by w. slingo. researches on magnetism. vi. natural history.--the giraffe.--with engraving. vii. medicine, and hygiene.--the treatment of cholera--by dr. h.a. rawlins. temperature. moisture, and pressure, in their relations to health.--london deaths under year in july, august, and part of september. consumption spread by chickens. new method of reducing fever. viii. miscellaneous.--the crown diamonds of france at the exhibition of industrial arts. a new mode of testing the economy of the expenses of management in life insurance.--by walter c. wright. * * * * * the giraffe. the spirited view herewith presented, representing the "fall of the giraffe" before the rifle of a sportsman, we take from the _illustrated london news_. hunting the giraffe has long been a favorite sport among the more adventurous of british sportsmen, its natural range being all the wooded parts of eastern, central, and southern africa, though of late years it has been greatly thinned out before the settlements advancing from the cape of good hope. [illustration: the fall of the giraffe.] the characteristics of this singular animal are in some particulars those of the camel, the ox, and the antelope. its eyes are beautiful, extremely large, and so placed that the animal can see much of what is passing on all sides, and even behind it, so that it is approached with the greatest difficulty. the animal when full grown attains sometimes a height of fifteen to seventeen feet. it feeds on the leaves and twigs of trees principally, its immense length of legs and height at the withers rendering it difficult for the animal to graze on an even surface. it is not easily overtaken except by a swift horse, but when surprised or run down it can defend itself with considerable vigor by kicking, thus, it is said, often tiring out and beating off the lion. it was formerly almost universally believed that the fore legs were longer than the hinder ones, but in fact the hind legs are the longer by about one inch, the error having been caused by the great development and height of the withers, to give a proper base to the long neck and towering head. the color varies a good deal, the head being generally a reddish brown, and the neck, back, and sides marked with tessellated, rust colored spots with narrow white divisions. many specimens have been brought to this country, the animal being extremely docile in confinement, feeding from the hand, and being very friendly to those who are kind to it. * * * * * an experiment has been made in vienna which proves that even with incandescent lights special precautions must be taken to avoid any risk of fire. a lamp having been enveloped with paper and lighted by a current, the heat generated was sufficient to set fire to the paper, which burnt out and caused the lamp to explode. * * * * * the temperature of the earth as shown by deep mines. at a recent meeting of the american society of civil engineers, observations on the temperature of the earth, as shown by deep mines, were presented by messrs. hamilton smith, jr., and edward b dorsey. mr. smith said that the temperature of the earth varies very greatly at different localities and in different geological formations. there are decided exceptions to the general law that the temperature increased with the depth. at the new almaden quicksilver mine, in california, at a depth of about feet the temperature was very high--some degrees; but in the deepest part of the same mine, , feet below the surface and feet below sea level, the temperature is very pleasant, probably less than degrees. at the eureka mines, in california, the air , feet below the surface appears nearly as cool as feet below the surface. the normal temperature of the earth at a depth of or feet is probably near the mean annual temperature of the air at the particular place. at the comstock mines, some years since, the miners could remain but a few moments at a time, on account of the heat. ice water was given them as an experiment; it produced no ill effects, but the men worked to much better advantage; and since that time, ice water is furnished in all these mines, and drunk with apparently no bad results. mr. e.b. dorsey said that the mines on the comstock vein, nevada, were exceptionally hot. at depths of from , to , feet, the thermometer placed in a freshly drilled hole will show degrees. very large bodies of water have run for years at degrees, and smaller bodies at degrees. the temperature of the air is kept down to degrees by forcing in fresh air cooled over ice. captain wheeler, u.s. engineers, estimated the heat extracted annually from the comstock by means of the water pumped out and cold air forced in, as equal to that generated by the combustion of , tons of anthracite coal or , cords of wood. observations were then given upon temperature at every feet in the forman shaft of the overman mine, running from degrees at a depth of feet to . degrees at a depth of , feet. the temperature increased: to , feet deep, increase degree in feet. to , feet deep, increase degree in . feet. to , feet deep, increase degree in . feet. a table was presented giving the temperatures of a large number of deep mines, tunnels, and artesian wells. the two coolest mines or tunnels are in limestone, namely, chanarcillo mines and mont cenis tunnel; and the two hottest are in trachyte and the "coal measures," namely, the comstock mines in trachyte and the south balgray in the "coal measures." mr. dorsey considered that experience showed that limestone was the coolest formation. * * * * * gallisin, an unfermentable substance in starch sugar. c. schmitt and a. coblenzl have made a careful investigation of the unfermentable substances found in commercial starch sugars, and have succeeded in isolating a definite compound, to which they give the name gallisin. the method of separation and purification which they made use of is as follows: kilogrammes of commercial starch sugar were allowed to ferment. at a temperature of - ° c. and with a solution containing per cent. the fermentation was complete in five to six days. it was filtered; the perfectly clear, almost colorless, liquid evaporated as far as possible on the water-bath, and the sirup while still warm brought into a good-sized flask. the sirup was then well shaken with a large excess of absolute alcohol, when it became viscous, but did not mix with the alcohol. the latter was poured off, replaced by fresh alcohol, and again shaken. when this shaking with alcohol has been repeated several times, the sirup is finally changed to a yellowish-gray mass. this is now brought into a large mortar, and rubbed up under a mixture of alcohol and ether. after some time the whole mass is transformed into a gray powder. it is quickly filtered off with the aid of an aspirator, washed with alcohol and then with ether, and brought under a desiccator with concentrated sulphuric acid. in order to purify the substance, it is dissolved in water and treated with bone-black. the solution is then evaporated to a sirup, and this poured into a mixture of equal parts of anhydrous alcohol and ether. in this way the new compound is obtained as a very fine, pure white powder which rapidly settles. it has much the appearance of starch. under the microscope it is perfectly amorphous. in the air it deliquesces much more rapidly than ignited calcium chloride. treated with dilute mineral acids or oxalic acid on the water-bath gallisin is transformed into dextrose. it does not ferment when treated in water solution with fresh yeast. the analyses led to the formula c_{ }h_{ }o_{ }. when treated under pressure with three times its weight of acetic anhydride at - ° it dissolves perfectly. from the solution a product was separated which on analysis gave results agreeing with the formula c_{ }h_{ }o_{ }(c_{ }h_{ }o)_{ }. the substance appears therefore to be hexacetylgallisin. physiological experiments on lower animals and human beings demonstrated clearly that gallisin has neither directly nor indirectly any injurious effect on the health.--_berichte der deutschen chemischen gesellschaft, , ; amer. chem. jour._ * * * * * the combining weights, volumes, and specific gravities of elements and compounds. under the title of "figures worth studying," mr. william farmer, of new york, read a paper before a recent meeting of the society of gas lighting, from which the _american gas light journal_ gives the following: i have prepared the following table, which contains some of the elements and compounds, with their combining weights, volumes, and specific gravities. when the combining weight of any of these elements and compounds is taken in pounds, then the gas or vapor therefrom will always occupy about . cubic feet of space, at ° fahr. and inches barometer. if we divide this constant . by the combining weight of any of the substances, then the quotient will be the number of cubic feet per pound of the same. if we divide the combining weight of any of the substances given in the table by , then the quotient will give the density of the same, as compared with hydrogen. if we divide the combining weight of any of the substances by the constant . , then the quotient will be the specific gravity of the gas or vapor therefrom, as compared with air. all the calculations are based on the atomic weights which are now generally adopted by the majority of chemists. ------------------------------------------------------------------- | | |cub. ft.| | | | | per | | | combi- |cub. ft.| combi- |specific| | ning | per | ning |gravity | |weight. | pound. |weight. |air = .| ------------------------------+--------+--------+--------+--------| hydrogen (h_{ }) | . | . | . | . | carbon vapour (c_{ }) | . | . | . | . | nitrogen (n_{ }) | . | . | . | . | oxygen (o_{ }) | . | . | . | . | chlorine (cl_{ }) | . | . | . | . | bromine (br_{ }) | . | . | . | . | flourine (f_{ }) | . | . | . | . | iodine (i_{ }) | . | . | . | . | sulphur (s_{ }) | . | . | . | . | phosphorus (p_{ }) | . | . | . | . | carbonic oxide (co) | . | . | . | . | carbonic acid (co_{ }) | . | . | . | . | water vapour (h_{ }o) | . | . | . | . | hydrogen sulphide (h_{ }s) | . | . | . | . | ammonia (h_{ }n) | . | . | . | . | sulphurous oxide (so_{ }) | . | . | . | . | sulphuric oxide (so_{ }) | . | . | . | . | cyanogen (c_{ }n_{ }) | . | . | . | . | bisulphide of carbon (cs_{ }) | . | . | . | . | ethyl alcohol (c_{ }h_{ }o) | . | . | . | . | ethyl ether (c_{ }h_{ }o) | . | . | . | . | methyl alcohol (ch_{ }o) | . | . | . | . | methyl chloride (ch_{ }cl) | . | . | . | . | carbonyl chloride (cocl_{ }) | . | . | . | . | phosphine gas (ph_{ }) | . | . | . | . | hydrochloric acid (hcl) | . | . | . | . | methane (ch_{ }) | . | . | . | . | ethane (c_{ }h_{ }) | . | . | . | . | propane (c_{ }h_{ }) | . | . | . | . | butane (c_{ }h_{ }) | . | . | . | . | ethene (c_{ }h_{ }) | . | . | . | . | propene (c_{ }h_{ }) | . | . | . | . | butene (c_{ }h_{ }) | . | . | . | . | ethine (c_{ }h_{ }) | . | . | . | . | propine (c_{ }h_{ }) | . | . | . | . | butine (c_{ }h_{ }) | . | . | . | . | quintone (c_{ }h_{ }) | . | . | . | . | benzene (c_{ }h_{ }) | . | . | . | . | styrolene (c_{ }h_{ }) | . | . | . | . | naphtalene (c_{ }h_{ }) | . | . | . | . | turpentine (c_{ }h_{ }) | . | . | . | . | dry air | . | . | -- | . | * * * * * emerald-green: its properties and manufacture.[ ] [footnote : this substance is also known by the name schweinfurt green.] by robert galloway, m.r.i.a. the poisonous effects of wall-paper stained with emerald-green (aceto-arsenite of copper) appears to be a very favorite topic in many journals; it is continually reappearing in one form or another in different publications, especially medical ones; there has recently appeared a short reference to it under the title, "the poisonous effect of wall-paper." as some years ago i became practically acquainted with its properties and manufacture, a few observations on these subjects may not be without interest. in the paragraph referred to, it is stated that the poisonous effect of this pigment cannot be _entirely_ due to its mere mechanical detachment from the paper. this writer therefore attributes the poisonous effects to the formation of the hydrogen compound of arsenic, viz., arseniureted hydrogen (ash_{ }); the hydrogen, for the formation of this compound, being generated, the writer thinks probable, "by the joint action of moisture and organic matters, viz., of substances used in fixing to walls papers impregnated with arsenic." in some of our chemical manuals, dr. kolbe's "inorganic chemistry," for example, it is also stated that arseniureted hydrogen is formed by the _fermentation_ of the starch-paste employed for fastening the paper to the walls. it is perfectly obvious that the fermentation of the starch-paste must cease after a time, and therefore the poisonous effects of the paper must likewise cease if its injurious effects are caused by the fermentation. i do not think that arseniureted hydrogen could be formed under the _conditions_, for the oxygen compound of arsenic is in a state of combination, and the compound is in a dry solid state and not in solution and the affinities of the two elements--arsenic and hydrogen--for each other are so exceedingly weak that they cannot be made to unite directly except they are both set free at the same moment in presence of each other. further, for the formation of this hydrogen compound by the fermentation of the starch, or by the growth of minute fungi, the _entire_ compound must be broken up, and therefore the pigment would become discolored; but aceto-arsenite of copper ( cuas_{ }o_{ }+cu(c_{ }h_{ }o_{ })_{ }) is a very stable compound, not readily undergoing decomposition, and is consequently a very permanent color. it has also been not unfrequently stated that the injurious effects of this pigment are due to the arsenious oxide volatilizing from the other constituents of the compound. this volatilization would likewise cause a breaking up of the entire compound, and would consequently cause a discoloration of the paper; but the volatilization of this arsenic compound is in every respect most improbable. the injurious effects, if any, of this pigment must therefore be due to its mechanical detachment from the paper; but has it ever been conclusively proved that persons who inhabit rooms the wall-paper of which is stained with emerald-green suffer from arsenical poisoning? if it does occur, then the effects of what may be termed homoeopathic doses of this substance are totally different from the effects which arise from larger doses. during the packing of this substance in its dry state in the factory, clouds of its dust ascend in the air, and during the time i had to do with its manufacture i never heard that any of the factory hands suffered, nor did i suffer, from arsenical poisoning. if there is any abrasion of the skin the dust produces a sore, and also the delicate lining of the nostrils is apt to be affected. it is in this way it acts in large doses; i am therefore very skeptical as to its supposed poisonous effects when wall-paper is stained with it. different methods are given in works on chemistry for the manufacture of this pigment, but as they do not agree in every respect with the method which was followed in english color factories some years ago, it will be as well, for the full elucidation of the manufacture of this substance, to briefly recite some of these methods before describing the one that was, and probably is still, in use; and i will afterward describe a method which i invented, and which is practically superior to any other, both in the rapidity with which the color can be formed, and for producing it at a less cost. it is stated in watts' "dictionary of chemistry" that it is "prepared on a large scale by mixing arsenious acid with cupric acetate and water. five parts of verdigris are made up to a thin paste, and added to a boiling solution of parts or rather more of arsenious acid in parts of water. the boiling must be well kept up, otherwise the precipitate assumes a yellow-green color, from the formation of copper arsenite; in that case acetic acid must be added, and the boiling continued a few minutes longer. the precipitate then becomes crystalline, and acquires the fine green color peculiar to the aceto-arsenite." i do not know from personal knowledge, but i have always understood that the copper salt employed in its manufacture in france is the acetate. this would account, in my opinion, for the larger crystalline flakes in which it is obtained in france than can be produced by the english method of manufacturing it. cupric acetate is never employed, i believe, in england--the much cheaper copper salt, the sulphate, being always employed. in "miller's chemistry" it is stated it "may be obtained by _boiling_ solutions of arsenious anhydride and cupric acetate, and adding to the mixture an equal bulk of _cold_ water." why it should be recommended to add _cold water_, i am at a loss to understand. in drs. roscoe and schorlemmer's large work on "chemistry," and in the english edition of "wagner's handbook of chemical technology," edited by mr. crookes, the process as described by dr. ehrmann in the "ann. pharm.," xii., , is given. it is thus stated in wagner's work: "this pigment is prepared by first separately dissolving equal parts by weight of arsenious acid and neutral acetate of copper in boiling water, and next mixing these solutions while boiling. there is immediately formed a flocculent olive-green colored precipitate of arsenite of copper, while the supernatant liquid contains free acetic acid. after a while the precipitate becomes gradually crystalline, at the same time forming a beautiful green pigment, which is separated from the liquid by filtration, and after washing and carefully drying is ready for use. the mode of preparing this pigment on a large scale was originally devised by m. braconnot, as follows: kilos. of sulphate of copper are dissolved in the smallest quantity of boiling water, and mixed with a boiling and concentrated solution of arsenite of soda or potassa, so prepared as to contain kilos. of arsenious acid. there is immediately formed a dirty greenish-colored precipitate which is converted into schweinfurt green by the addition of some liters of concentrated wood-vinegar. this having been done, the precipitate is immediately filtered off and washed." as i have already stated, the copper salt used in the manufacture of this pigment in england is the sulphate, and it is carried out pretty much according to braconnot's method as described by dr ehrmann; but any one would infer, from reading his description of the manufacturing process, that the compound, aceto-arsenite of copper, was formed almost immediately after the addition of the acetic acid, a higher or lower atmospheric temperature having no effect in hastening or retarding the formation. furthermore, it is not stated whether the compound forms more readily in an acid or neutral solution, or whether it can or cannot be formed in a neutral one; now both these points are important to notice in describing its manufacture. as regards the former i shall notice it presently, and, as far as my knowledge extends, the pigment will not form when the solution is neutral. the operation is conducted in the following manner in the factory: the requisite quantity of sulphate of copper is placed in a large wooden vat, and hot water added to dissolve it; the requisite quantity of arsenic (arsenious anhydride) and carbonate of soda, the latter not in quantity quite sufficient to neutralize the whole of the sulphuric acid set free from the sulphate of copper on the precipitation of the copper as arsenite, are placed in another wooden vessel; water is then added, and the formation of the arsenite of soda and its solution are aided by the introduction of steam into the liquid. when complete solution has been effected the arsenic solution is run off into the vat containing the solution of the sulphate of copper, arsenite of copper being at once precipitated. the necessary quantity of acetic acid is afterward added. in _warm_ weather the formation of the aceto-arsenite soon commences after the addition of the vinegar; but, even in that case, it takes a week or more to have the whole of a big batch of arsenite converted into the aceto-arsenite; and perfect conversion is necessary, as the presence of a very minute quantity of unchanged arsenite lowers very much the price of the emerald pigment, and a by no means large quantity renders the pigment unsalable, owing to its dirty yellowish-green color. in cold weather a much longer time is required for its complete conversion; even at the end of a fortnight or three weeks there frequently remains sufficient unconverted arsenite to affect seriously the selling price of the color; when this occurs the manufacturer generally removes these last traces by a most wasteful method viz, by adding a quantity of free sulphuric acid. the acid of course dissolves the arsenite, but it dissolves in very much larger quantities the aceto-arsenite; and this costly solution is not utilized, but is run into the factory sewer. by my method of manufacturing it, it can be produced in winter as well as in summer in one or two hours, and the quantity of free acid required for its formation is reduced to the lowest amount. i proceed as follows: after having dissolved in hot water the requisite quantity of cupric sulphate, i decompose one-fourth of this salt by adding just sufficient of a solution of carbonate of soda to precipitate the copper, in that quantity of the sulphate, as carbonate. i then add just sufficient acetic acid to convert the carbonate into acetate. i have now got in solution-- cuso_{ } + cu(c_{ }h_{ }o_{ })_{ }, and i have to transform it into-- cuas_{ }o_{ } + cu(c_{ }h_{ }o_{ })_{ }. it is at once seen that i have got the requisite quantity of acetate formed. i next dissolve the requisite quantity of arsenious anhydride in an amount of carbonate of soda _rather less_ than is sufficient to neutralize the acid in the remaining cupric sulphate, and i then bring the solution to or near the boiling-point by introducing steam into it; the arsenic is dissolved not in the same vessel as the copper salt, but in a separate one. when the arsenic solution is fully heated, a small current of it is allowed to flow into the vat containing the copper salts, and brisk stirring is kept up in the vat. the emerald green is at once formed; but if there should be the slightest formation of any arsenite, the flow of the arsenic solution is at once stopped until every trace of the arsenite has been converted; the arsenic solution is then allowed to flow in again, with the same precautions as before; in this way a large batch of emerald-green can he formed in one or two hours, without containing the slightest trace of the arsenite. i keep the arsenic solution near the boiling-point during the whole of the time it is flowing into the other vessel. by varying the proportions of water i could either make it coarse or fine, as i wished, which is an important matter to have complete control over in its manufacture. two points of interest occurred to me during the time i was occupied with the research, which i had not time to complete; one was whether the aceto-arsenite can be formed, adopting the old method for its formation, if there is more than a certain quantity of water; from some experiments i made in this direction i was inclined to the opinion it could not. i have already stated that emerald-green is soluble to a certain extent in acids, and that it is formed in a more or less acid solution; consequently a varying amount of the pigment is always lost by being dissolved in the supernatant liquid. to prevent to a certain extent this loss i precipitated the copper from it as arsenite; but i was not successful in the few experiments i had time to make on this part of the subject of reconverting the copper arsenite thus obtained into the aceto-arsenite by the addition of acetic acid.--_jour. of science._ * * * * * analysis of zinc ash and calcined pyrites by means of ammonium carbonate. in a recent issue of the _chemiker zeitung_ dr. kosmann has reported an analytical method for the examination of zinciferous products; according to this report, the ash and flue dust produced by the extraction of zinc from its ore comprise: . zinc dust, from the distillation of zinc, . flue dust, condensed in chambers of zinc furnaces with kleemann's receivers, . zinc ash, of various assortments, from iron blast furnaces. of these, zinc dust is the only ready product which is, as color or reducing agent, employed in analytical and technical processes. its value, when serving the latter purpose, is determined by the percentage of finely divided metallic zinc and cadmium contained therein; of equal reducing power is cadmium, generally associating zinc; injurious, and therefore uneffective, are zinc oxide and oxides of other metals, also metallic lead. flue dust, condensed in chambers of zinc furnaces with kleemann's receivers, is employed with zinc ores in the extraction of zinc, and in small quantities as substitute for zinc white; its commercial value is similarly estimated as that of zinc ores. the various modifications of zinciferous flue ashes from blast furnaces are an object for continual demand, being both a valuable material for the production of zinc and, in its superior qualities, a desirable pigment. in the regeneration of zinc the presence of foreign substances is of some concern; detrimental are lead, sulphur, and sulphuric acid in form of lead, zinc, and lime sulphate. the chemico-technical analysis of these products has until recently been confined to the volumetric determination of zinc by means of sodium sulphide (schaffner's method). but as a remnant of sulphur, as sulphuric acid, in roasted blende causes a material loss during distillation, and otherwise being induced to produce a zinc free of lead, the estimation of sulphur, sulphuric acid, and lead became necessary. these impurities are determined by well-known methods; sulphur is oxidized and precipitated with barium chloride, lead by sulphuric acid and alcohol. the examination of zinc dust, when used for the regeneration of metal, determines the quantity of zinc resident therein, and employed as reducing agent, the quantity of metal which causes the generation of hydrogen. cadmium, showing the same deportment, must also be considered as well as lead and arsenic. a most complete and rapidly working method for the examination of zinciferous products has originated with the application of neutral ammonium carbonate as solvent. a solution of this preparation is made, according to h. rose, by dissolving grm. commercial ammon carbonate in c.c. ammoniacal liquor of . s.g., and, by addition of water, augmenting it to one liter. this solution dissolves the metallic components, their oxides, and basic zinc sulphate, and transfers cadmium and lead oxide, also lead, magnesium, and lime sulphate, into insoluble carbonates. iron and manganese, when present as protoxide, are dissolved; of iron sesquioxide but traces, and of cadmium oxide _in statu nascendi_ a small portion enter into solution. the solution of ammonium carbonate contains in each c.c. grm. ammonia, which dissolves . grm. zinc. the sample for examination is moistened with water and mixed with an adequate volume of the solvent, is digested at - ° c. until complete decomposition is effected. the heating of the liquid prevents the solution of iron, manganese, and cadmium. the content, sediment and liquid, is thrown on a filter and washed with hot water to which a small quantity of the solvent has been added. when the solution contains iron and manganese, it is separated by decantation from the sediment and oxidized with bromine (according to the method of nic-wolff) until a flocculent precipitate of iron sesquioxide and manganese dioxide becomes visible; it is united with the original residue and filtered. the filtrate is diluted till it appears cloudy, boiled to expel ammonia, tested with sodium sulphide upon the presence of zinc, and, when freed of all zinc, decanted. the precipitate of zinc carbonate is filtered, exhausted with water, transferred into zinc oxide by ignition, and weighed. the gravimetric method can be substituted by the volumetric by introducing a solution of sodium sulphide of known strength into the ammoniacal filtrate. on dividing the filtered liquid into various equal portions other substances, arsenic and sulphuric acid, can be determined from the same sample. for this purpose the filtrate is concentrated; divided into two equal portions, one of which is acidified and treated with hydrogen sulphide for the determination of arsenic, the other is acidified and used for the estimation of sulphuric acid by means of barium chloride. the original residue is dissolved in muriatic or acetic acid and filtered. the lead of the filtered liquid is thrown down by sulphuric acid, and alcohol, and cadmium, after dissipation of alcohol into gas, precipitated by hydrogen sulphide. iron, manganese, alumina, and other substances present in the solution are determined by known methods. it is manifest that the determination of substances--zinc, lead, and sulphuric acid--which are of importance in technical analysis of zinc ash, can be executed by this method within a comparatively short time. the application of ammonium carbonate as solvent has the advantage, over the application of ammonia, that it is a far better solvent, that it decomposes insoluble basic sulphates, and that the remaining carbonates are readily dissolved by acids. the decomposition of zinc dust is accompanied by a lively evolution of gas; it is therefore necessary to continue the digestion of the sample till no more hydrogen is given off. zinc dust contains both metals and their oxides, and methods which, from the volume of hydrogen generated, determine indirectly the percentage of metallic zinc do not give the real composition of the zinc dust. for the determination of the metallic components the material is digested with a solution of copper sulphate, which dissolves zinc and cadmium; the liquid is filtered, acidified, and decomposed with hydrogen sulphide, or treated with a solution of ammonium carbonate. the use of cupric chloride is not advisable, as it corrodes lead, and gives rise to the formation of soluble chloride of lead, which complicates the separation of zinc from cadmium. the best mode of operation is the following: both copper sulphate and zinc dust are weighed separately, the former is dissolved in water and the latter introduced into the solution of copper sulphate in small portions until it appears colorless. during the operation the vessel is freely shaken, lumps are comminuted with a glass rod, and a few drops of the liquid are ultimately tested with hydrogen sulphide or ammonia. the remainder of zinc dust is then weighed, and its value deducted from the original weight. zinc and cadmium of the filtrate are determined as above. on repeating this method several times most satisfactory results are obtained. another mode of operating is to employ an excess of copper sulphate and to determine the copper dissolved in the filtrate. the separation of copper from cadmium being difficult and laborious, and the volumetric estimation with potassium cyanide not practicable, it is not prudent to apply this method. when calcined zinciferous pyrites have to be examined, the estimation of zinc is similar to that employed in the analysis of zinc ore. the sample is exhausted with water, filtered, and, to eliminate calcium sulphate and basic iron sulphate, evaporated to dryness. it is then dissolved in a small quantity of alcohol and water, refiltered, and the filtrate decomposed with ammonium carbonate. the original residue is treated with a solution of ammonium carbonate, which dissolves arsenious acid and basic zinc sulphate, filtered, and united with the first filtrate. when iron and manganese are present, the filtrates are treated with bromine. the united filtrates are boiled or examined volumetrically with sodium sulphide. * * * * * petroleum as fuel in locomotive engines.[ ] [footnote : abstract of paper read before the institution of mechanical engineers.] by mr. thomas urquhart. comparing naphtha refuse and anthracite, the former has a theoretical evaporative power of . lb. of water per lb. of fuel, and the latter of . lb., at a pressure of atm. or lb. per square inch; hence petroleum has, weight for weight, per cent. higher evaporative value than anthracite. now in locomotive practice a mean evaporation of from lb. to ½ lb. of water per lb. of anthracite is about what is generally obtained, thus giving about per cent. efficiency, while per cent. of the heating power is unavoidably lost. but with petroleum an evaporation of . lb. is practically obtained, giving . / . = per cent. efficiency. thus in the first place petroleum is theoretically per cent. superior to anthracite in evaporative power; and secondly, its useful effect is per cent. greater, being percent. instead of percent.; while, thirdly, weight for weight, the practical evaporative value of petroleum must be reckoned as at least from ( . - . )/ . = per cent. to ( . - . )/ . = per cent. higher than that of anthracite. _spray injector._--steam not superheated, being the most convenient for injecting the spray of liquid fuel into the furnace, it remains to be proved how far superheated steam or compressed air is really superior to ordinary saturated steam, taken from the highest point inside the boiler by a special internal pipe. in using several systems of spray injectors for locomotives, the author invariably noticed the impossibility of preventing leakage of tubes, accumulation of soot, and inequality of heating of the fire box. the work of a locomotive boiler is very different from that of a marine or stationary boiler, owing to the frequent changes of gradient on the line, and the frequent stoppages at stations. these conditions render firing with petroleum very difficult; and were it not for the part played by properly arranged brickwork inside the fire box, the spray jet alone would be quite inadequate. hitherto the efforts of engineers have been mainly directed toward arriving at the best kind of "spray injector," for so minutely subdividing a jet of petroleum into a fine spray, by the aid of steam or compressed air, as to render it inflammable and of easy ignition. for this object nearly all the known spray injectors have very long and narrow orifices for petroleum as well as for steam; the width of the orifices does not exceed from ½ mm. to mm. or . in. to . in., and in many instances is capable of adjustment. with such narrow orifices it is clear that any small solid particles which may find their way into the spray injector along with the petroleum will foul the nozzle and check the fire. hence in many of the steamboats on the caspian sea, although a single spray injector suffices for one furnace, two are used, in order that when one gets fouled the other may still work; but, of course, the fouled orifices require incessant cleaning out. _locomotives._--in arranging a locomotive for burning petroleum, several details are required to be added in order to render the application convenient. in the first place, for getting up steam to begin with, a gas pipe of inch internal diameter is fixed along the outside of the boiler, and at about the middle of its length it is fitted with a three-way cock having a screw nipple and cap. the front end of the longitudinal pipe is connected to the blower in the chimney, and the back end is attached to the spray injector. then by connecting to the nipple a pipe from a shunting locomotive under steam, the spray jet is immediately started by the borrowed steam, by which at the same time a draught is also maintained in the chimney. in a fully equipped engine shed the borrowed steam would be obtained from a fixed boiler conveniently placed and specially arranged for the purpose of raising steam. in practice steam can be raised from cold water to atm. pressure-- lb. per square inch--in twenty minutes. the use of auxiliary steam is then dispensed with, and the spray jet is worked by steam from its own boiler; a pressure of atm.-- lb.--is thus obtained in fifty to fifty-five minutes from the time the spray jet was first started. in daily practice, when it is only necessary to raise steam in boilers already full of hot water, the full pressure of to atm. is obtained in from twenty to twenty-five minutes. while experimenting with liquid fuel for locomotives, a separate tank was placed on the tender for carrying the petroleum, having a capacity of about tons. but to have a separate tank on the tender, even though fixed in place, would be a source of danger from the possibility of its moving forward in case of collision. it was therefore decided, as soon as petroleum firing was permanently introduced, to place the tank for fuel in the tender between the two side compartments of the water tank, utilizing the original coal space. for a six-wheeled locomotive the capacity of the tank is - / tons of oil--a quantity sufficient for miles, with a train of tons gross exclusive of engine and tender. in charging the tender tank with petroleum, it is of great importance to have strainers of wire cloth in the manhole of two different meshes, the outer one having openings, say, of / in., the inner, say / in.; these strainers are occasionally taken out and cleaned. if care be taken to prevent any solid particles from entering with the petroleum, no fouling of the spray injector is likely to occur; and even if an obstruction should arise, the obstacle being of small size can easily be blown through by screwing back the steam cone in the spray injector far enough to let the solid particles pass and be blown out into the fire-box by the steam. this expedient is easily resorted to even when running; and no more inconvenience arises than an extra puff of dense smoke for a moment, in consequence of the sudden admission of too much fuel. besides the two strainers in the manhole of the petroleum tank on the tender, there should be another strainer at the outlet valve inside the tank, having a mesh of / in. holes. _driving locomotives._--in lighting up, certain precise rules have to be followed, in order to prevent explosion of any gas that may have accumulated in the fire box. such explosions do often take place through negligence; but they amount simply to a puff of gas, driving smoke out through the ash-pan dampers, without any disagreeably loud report. this is all prevented by adhering to the following simple rules: first clear the spray nozzle of water by letting a small quantity of steam blow through, with the ash-pan doors open; at the same time start the blower in the chimney for a few seconds, and the gas, if any, will be immediately drawn up the chimney. next place on the bottom of the combustion chamber a piece of cotton waste, or a handful of shavings saturated with petroleum and burning with a flame. then by opening first the steam valve of the spray injector, and next the petroleum valve gently, the very first spray of oil coming on the flaming waste immediately ignites without any explosion whatever; after which the quantity of fuel can be increased at pleasure. by looking at the top of the chimney, the supply of petroleum can be regulated by observing the smoke. the general rule is to allow a transparent light smoke to escape, thus showing that neither too much air is being admitted nor too little. the combustion is quite under the control of the driver, and the regulation can be so effected as to prevent smoke altogether. while running, it is indispensable that the driver and fireman should act together, the latter having at his side of the engine the four handles for regulating the fire, namely, the steam wheel and the petroleum wheel for the spray injector, and the two ash-pan door handles in which there are notches for regulating the air admission. each alteration in the position of the reversing lever or screw, as well as in the degree of opening of the steam regulator or the blast pipe, requires a corresponding alteration of the fire. generally the driver generally passes the word when he intends shutting off steam, so that the alteration in the firing can be effected before the steam is actually shut off; and in this way the regulation of the fire and that of the steam are virtually done together. all this care is necessary to prevent smoke, which is nothing less than a waste of fuel. when, for instance, the train arrives at the top of a bank, which it has to go down with the brakes on, exactly at the moment of the driver shutting off the steam and shifting the reversing lever into full forward gear, the petroleum and steam are shut off from the spray injector, the ash-pan doors are closed, and if the incline be a long one, the revolving iron damper over the chimney top is moved into position, closing the chimney, though not hermetically. the accumulated heat is thereby retained in the fire-box; and the steam even rises in pressure, from the action of the accumulated heat alone. as soon as the train reaches the bottom of the incline and steam is again required, the first thing done is to uncover the chimney top; then the steam is turned on to the spray injector, and next a small quantity of petroleum is admitted, but without opening the ash-pan doors, a small fire being rendered possible by the entrance of air around the spray injector, as well as by possible leakage past the ash-pan doors. the spray immediately coming in contact with the hot chamber ignites without any audible explosion; and the ash-pan doors are finally opened, when considerable power is required, or when the air otherwise admitted is not sufficient to support complete combustion. by looking at the fire through the sight hole it can always be seen at night whether the fire is white or dusky; in fact, with altogether inexperienced men it was found that after a few trips they could become quite expert in firing with petroleum. the better men contrive to burn less fuel than others, simply by greater care in attending to all the points essential to success. at present seventy-two locomotives are running with petroleum firing; ten of them are passenger engines, seventeen are eight-wheel coupled goods engines, and forty-five are six-wheel coupled. as might be expected, several points have arisen which must be dealt with in order to insure success. for instance, the distance ring between the plates around the firing door is apt to leak, in consequence of the intense heat driven against it, and the absence of water circulation; it is therefore either protected by having the brick arch built up against it, or, better still, it is taken out altogether when the engines are in for repairs, and a flange joint is substituted, similar to what is now used in the engines of the london and northwestern railway. this arrangement gives better results, and occasions no trouble whatever. _storage of petroleum._--the length of line now worked with petroleum is from tsaritsin to burnack, miles. there is a main iron reservoir for petroleum at each of the four engine sheds, namely at tsaritsin, archeda, filonoff, and borisoglebsk. each reservoir is ft. internal diameter and ft. high, and when full holds about , tons. the method of charging the reservoir, which stands a good way from the line, and is situated at a convenient distance from all dwelling houses and buildings, is as follows: on a siding specially prepared for the purpose are placed ten cistern cars full of oil, the capacity of each being about ten tons. from each of these cars a connection is made by a flexible india rubber pipe to one of ten stand pipes which project ft. above the ground line. parallel with the rails is laid a main pipe, with which the ten stand pipes are all connected, thus forming one general suction main. about the middle of the length of the main, which is laid underground and covered with sawdust or other non-conducting material, is fixed a blake steam pump. as soon as all the ten connections are made with the cistern cars, the pump is set to work, and in about one hour the whole of the cars are discharged into the main reservoir, the time depending of course upon the capacity of the pump. all the pipes used are of malleable iron, lap-welded, and of in. internal diameter, having screwed coupling muffs for making the connections. at each engine shed, in addition to the main storage reservoir, there is a smaller distributing tank, which is erected at a sufficient height to supply the tenders, and very much resembles the ordinary water tanks. these distributing tanks are circular, about ½ ft. diameter and ft. high, and of ¼ in. plates; their inside mean area is calculated exactly, and a scale graduated in inches stands in the middle of the tank; a glass with scale is used outside in summer time. each inch in height on the scale is converted into cubic feet, and then by means of a table is converted into russian poods, according to the specific gravity at various temperatures. as it would be superfluous to graduate the table for each separate degree of temperature, the columns in the table show the weights for every degrees reaumur, which is quite sufficient: namely, from deg. to deg., from deg. to deg., and so on, down to - deg.; the equivalent fahrenheit range being from deg. down to - deg. suppose the filling of a tender tank draws off a height of in. from the distributing tank, at a temperature of say - deg. r., these figures are shown by the table to correspond with . poods = , lb., or . tons, of petroleum. this arrangement does very well in practice; both the quantity and the temperature are entered on the driver's fuel bill at the time of his taking in his supply. _engines._--the engines used in the trials were built by borsig, of berlin, schneider, of creusot, and the russian mechanical and mining company, of st. petersburg. their main dimensions and weights were about the same, as follows, all of them having six wheels coupled, and tons adhesive weight; as originally constructed they had ordinary fire boxes for burning anthracite or wood; cylinders - / in. diameter and in. stroke; slide valves, outside lap - / in., inside lap / in., maximum travel, - / in.; stephenson link motion; boiler pressure, lb. per square inch; six wheels, all coupled, ft. in. in diameter; distance between centers of leading and middle wheels, ft. - / in.; between middle and trailing, ft. - / in.; total length of wheel base, ft.; weight empty, on leading wheels, . tons; middle, . tons; trailing, . tons; total weight, . tons empty; weight in running order, on leading wheels, . tons; middle, . tons; trailing . tons; total weight, . tons in running order. tubes number ; outside diameter, - / in.; length between tube plates, ft. - / in.; outside heating surface, , square feet; fire box heating surface, square feet; total heating surface, , square feet; fire grate area, square feet; tractive power = per cent. of boiler pressure × (cyl. diam.)² × stroke / diameter of wheels = . × × ( . )² × / = . tons. ratio of tractive power to adhesion weight = . / . = / . . _tender._--contents: water, cubic feet, or , gallons, or ½ tons; anthracite, poods, or tons; or wood, ½ cubic sajene, or cubic feet; weight empty, . tons; weight in running order, . tons; six wheels. * * * * * _petroleum refuse--comparative trials with petroleum, anthracite, bituminous coal, and wood, between archeda and tsaritsin on grazi and tsaritsin railway, in winter time._ -----+---+-----+------+---+-----+------+-----------+-------------+------+------------ | l | | | | | | | | | o | | train | | | | consumption | | | c | | alone. | | | | including | | date.| o | | | | | | lighting up.| | .| m | |----+-----| | | | | cost | | o |train|num-| | dis-| car | | | of |atmospheric | t | |ber |gross|tance|miles.| fuel. |-------+-----| fuel |temperature | i | | of |load.| run.| | | | per | per | and | v | |loa-| | | | | total |train| train| weather. | e | |ded | | | | | |mile.| mile.| | . | |cars| | | | | | | | -----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------ | | | no.| tons|miles| | | | |pence.| -----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------ | | - | | | | , |anthracite.| | . | . |- ° to - ° | | - | | | | | | lb. | lb. | | reau., feb.| | | | | | | | | | | equiv. to | | - | | | | | | | | |- ° to - ½° | | - | | | | , |bituminous | . | . | . | fah. | | | | | | | coal. | lb. | lb. | | | | - | | | | , |petroleum | | . | . | strong | | | | | | refuse. | lb. | lb. | | side wind. -----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------ | | - | | | | , |anthracite.| . | . | . |- ° to - ° march| | | | | | | | lb. | lb. | | reau., | | - | | | | , |wood, in | . | . | . | equiv. to | | | | | | | billets. | c. ft.|c. ft| | ° to ° | | | | | | | | | fah. | | - | | | | , |petroleum | | . | . | light | | | | | | refuse. | lb. | lb. | | side wind. -----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------ prices of fuel: petroleum refuse, s. per ton; anthracite and bituminous coal, s. d. per ton; wood, in billets, s. per cubic sajene = cubic feet; equivalent to . d. per cubic foot. dimensions of locomotives: cylinders, / in. diam. and in. stroke; wheels, feet in. diam.; total heating surface, , sq. feet: total adhesion weight, tons; boiler pressure, to atm. the preceding table shows the results of comparative trials made in winter with different sorts of fuel, under exactly similar conditions as to type of engine, profile of line, and load of train. two sets of comparative trials were made, both of them in winter. the three engines used were some of those built by schneider. in comparison with anthracite, the economy in favor of petroleum refuse was per cent. in weight, and per cent. in cost. with bituminous coal there was a difference of per cent. in favor of petroleum as to weight and per cent. as to cost. as compared with wood petroleum was per cent. cheaper. at a speed of fourteen miles an hour up an incline of in the steam pressure was easily kept up at to ½ atm. with a no. injector feeding the boiler all the time. up to the present time the author has altered seventy-two locomotives to burn petroleum; and from his own personal observations made on the foot plate with considerable frost he is satisfied that no other fuel can compare with petroleum either for locomotives or for other purposes. in illustration of its safety in case of accident, a photograph was exhibited of an accident that occurred on the author's line on th december, , when a locomotive fired with petroleum ran down the side of an embankment, taking the train after it; no explosion or conflagration of any kind took place under such trying circumstances, thus affording some proof of the safety of the petroleum refuse in this mode of firing. although it is scarcely possible that petroleum firing will ever be of use for locomotives on the ordinary railways of coal-bearing england, yet the author is convinced chat, even in such a country, its employment would be an enormous boon on underground lines. * * * * * charcoal kilns. [illustration: kiln for burning charcoal.] in answer to the inquiry of a correspondent about charcoal making, we offer two illustrations that show a method of manufacture differing from that usually adopted, which is that of burning on the bare ground, and covering with soil or sods to exclude the air. these kilns are made of brick, one course being sufficient, bands of iron or timber framework being added to strengthen the brickwork with greater economy. the usual style is conical, and the size is feet in diameter, with an equal height, holding about cords of wood. the difference in price is - / d. per bushel in favor of these kilns as compared with the usual mounds, the burner being furnished with the use of the kilns, and the timber standing, the kiln burning costing - / d., and the other - / d. the kilns must be lined to about halfway up with fire-brick, the cost of which will vary with the locality, but will be about £ , and as to bushels of coal have been made per cord the extra yield on good charcoal and the lessening of the cost of making soon covers any extra outlay on the cost of the kilns. the wall of the kiln is carried up nearly straight for feet, when it is drawn in, so as to become bluntly conical. upon the top a plate of iron is fastened in the manner of the keystone of an arch, and bands of iron are passed round the kiln and drawn tight with screw bolts and nuts to strengthen it. double doors of sheet-iron are made at the bottom and near the tops, by which it is either filled or emptied, and a few air-holes (b), which may be stopped with loose bricks, left in the bottom. the second figure shows a kiln of another shape made to burn , bushels of charcoal, or about cords of wood. the shape is a parallelogram, having an arched roof, and it is strengthened by a framework of timber inches square. as the pressure of the gas is sometimes very great, the walls must be built a brick and a half thick to prevent their bursting. the usual size is feet wide and high, and feet in length, outside measure. the time occupied in filling, burning, and emptying a small cone is about three weeks, and four weeks is required for the larger ones.--_the gardeners' chronicle._ [illustration: kiln for burning charcoal.] * * * * * entrance, tiddington house, oxon. our illustration is a view of the entrance facade to tiddington house, oxfordshire, the residence of the rev. joshua bennett. the house is an old building of the georgian period, and though originally plain and unpretentious, its bold coved cornices under the eaves, its rubbed and shaped arches, moulded strings, and thick sash bars, made it of considerable interest to the admirers of the "queen anne" school of architecture, and led to the adoption of that style in the alterations and additions made last year, of which the work shown in our illustration formed a small part. between the "entrance facade" and the wall of the house there is a space of some twenty feet in length, which is inclosed by a substantially built conservatory-like erection of queen anne design, forming an outer hall. [illustration: entrance tiddington house oxon.--morris & stallwood--architects.] the works were executed by messrs. holly & butler, of nettlebed. the brick carving was beautifully done by the late mr. finlay; and the architects were messrs. morris & stallwood, of reading.--_the architect._ * * * * * new arrangement of the bichromate of potash pile. since poggendorff in thought of substituting in the bunsen battery a solution of bichromate of potash and sulphuric acid for nitric acid, and of thus making a single liquid pile of it, in suppressing the porous vessel, his idea has been taken up a considerable number of times. some rediscovered it simply, while others, who were better posted in regard to the work of their predecessors, took poggendorff's pile as he conceived it, and, considering the future that was in store for it, thought only of modifying it in order to render it better. among these, mr. grenet was one of the first to present the bichromate of potash pile under a truly practical form. as long ago as , in fact, he gave it the form that is still in use, and that is known as the bottle pile. thus constructed, this pile, as is well known, presents a feeble internal resistance, and a greater electro-motive power than the bunsen element. unfortunately, its energy rapidly decreases, and the alteration of the liquid, as well as the large deposit of oxide of chromium that occurs on the positive electrode, prevents its being employed in experiments of quite long duration. mr. grenet, it is true, obviated these two defects by first renewing the liquid slowly and continuously, and causing a current of air to bubble up in the pile so as to detach the oxide of chromium in measure as the deposit formed. thus improved, the bichromate pile was employed on a large scale in the lighting of the comptoir d'escompte. in an extensive application like this latter, the use of compressed air for renewing the liquid can be easily adapted to the bichromate pile, as the number of elements is great enough to allow of the putting in of all the piping necessary; but when it is only desired to use this pile for laboratory purposes, and when there is need of but a small number of elements, it is impossible to adopt mr. grenet's elements in the form required by an electric lighting installation. it becomes absolutely necessary, then, to come back to a simpler form, and attempt at the same time to obviate the defects which are inherent to its very principle. in accordance with this idea, it will be well to point out the arrangement adopted by mr. courtot for his bichromate of potash piles--an arrangement that is very simple, but, sufficiently well worked out to render the use of it convenient in a laboratory. [illustration: fig. .--courtot's arrangement of the bichromate pile.] fig. gives the most elementary form. it consists of an earthen vessel into which dip four carbon plates connected with each other by a copper ring which carries one of the terminals. in the center there is a cylindrical porous vessel that contains a very dilute and feebly acidulated solution of bichromate of potash into which dips a prism of zinc, which may be lifted by means of a rod when the pile ceases to operate. it is true that the presence of the porous vessel in the bichromate of potash element increases the internal resistance, but, as an offset, although it decreases the discharge, it secures constancy and quite a long duration for it. [illustration: fig. .--courtot's arrangement of the bichromate pile.] the elements thus constituted may be grouped, to the number of six, in a frame analogous to that shown in the engraving, and, sum total, form a small sized battery adapted to the current experiments of the laboratory, and capable of supplying two small four volt lamps for ten or twelve hours. we have had occasion to make use of these elements for the graduation of galvanometers, and, after ascertaining the constancy of the discharge, have found that the internal resistance of each couple is nearly . ohm, with an electro-motive force of two volts. as may be seen, these elements should, in general, all be mounted for tension, as they are in the figure, inasmuch as the mobility of the zincs permits, according to circumstances, of employing a variable number of them without changing anything. moreover, with zincs amalgamated in a special manner, the attack is imperceptible, and the work in open circuit need scarcely to be taken into consideration. yet, despite the qualities inherent to the arrangement that we have just described, that defect common to all bichromate of potash piles--the deposit of oxide of chromium upon the carbon--is not here avoided. it occurs quite slowly, to be sure, but it does occur, and, from this point of view, the arrangement shown in fig. is preferable. the elements here are composed of prismatic porcelain vessels containing, as before, the solution and porous vessel. [illustration: fig. .--courtot's arrangement of the bichromate pile.] the whole is covered with a sheet of ebonite connected with the zinc and the two carbon plates in such a way that when the pile is not in operation the whole can be lifted from the liquid. under such circumstances the deposit of oxide is notably diminished, and the duration of the discharge is consequently greatly increased. fig. shows the details of a windlass that permits of lifting, according to circumstances, all the elements of the same trough or only a part of them. to effect this, the drum around which the chain winds that carries the carbons is mounted upon a sleeve fixed upon the axle. this latter is actuated by a winch; and a ratchet wheel, r, joined to a click which is actuated by a spiral spring, prevents the ebonite plates from falling back when it is desired to place the bolt under the button, b, of the spring. when it is desired to put an element out of the circuit, it is only necessary to act with the finger upon the extremity of the lever, d. under the action of the latter, the piece, _s_, which carries a groove for the passage of the screws that fix it to the upper cross-piece, takes on a longitudinal motion and consequently gears with the drum through the toothed sleeve, e. when an experiment is finished the zinc may thus be lifted from the liquid, and the deposit of oxide be prevented from forming upon the carbon. as may be seen, the arrangements which we have just described exhibit nothing that is particularly original. the windlasses used for removing the elements from a pile when the circuit is open have been employed for a long time; the bichromate pile is itself old, and, as we said in the beginning, it has been modified in its details a number of times. in spite of this, we have thought it well to point out the mode of construction adopted by mr. courtot, since, owing to the simplicity of the arrangements, it renders convenient and easily manageable a pile of very great constancy that may be utilized for supplying incandescent lamps, as well as for the most varied experiments of the laboratory.--_la lumiere electrique._ * * * * * the distribution of electricity by induction. there has been much said in recent times about the distribution of electricity by means of induction coils, and the use of this process has given rise to several systems that differ but little from one another in principle. the following are a few details in regard to a system due to a dutch engineer: in the month of december, , a patent relating to the distribution of electricity was taken out in germany and other countries by mr. b. haitzema enuma, whose system is based upon a series of successive inductions. the primary current developed by a dynamo-electric machine gives rise to secondary, tertiary, etc., currents. the principal line runs through the streets parallel with their axes, and, when the arrangement of the places is adapted thereto, it is closed upon the generator itself. in those frequent cases where it is necessary to cause the line to return over a path that it has already traversed, it is more advantageous to effect the return through the earth or to utilize the street water mains or gas pipes as conductors. this return arrangement may likewise be applied to the lines of secondary, tertiary, etc., order, as may easily be seen. the induction is effected by the aid of bobbins whose interior consists of a bundle of soft iron. the wire of the inducting current is wound directly around this core. the wire of the induced current is superposed upon the first and presents a large number of spirals. it is useless to say that these wires must be perfectly insulated from each other, as well as from the soft iron core. we shall call primary bobbins those which are interposed in the principal line, and secondary bobbins those in which the inducting current is a secondary one, and so on. it will be at once seen that this arrangement permits of continuing the distribution of electricity to the interior of buildings by the simple adjunction of one or several bobbins. each electric apparatus, whether it be a lamp or other mechanism, is furnished with a special current. if the number of these apparatus be increased, it is only necessary to increase the number of bobbins in the same ratio, on condition, be it understood, that the intensity of the currents remain sufficient to secure a proper working of the apparatus in question. when such intensity diminishes to too great a degree, the bobbin must be replaced by a stronger one. [illustration: distribution of electricity by induction.] it results from what precedes that each apparatus must be put in in such a way as to permit, of the opening and closing of the corresponding circuit. this arrangement, moreover, has no need of being dependent upon the apparatus, and may just as well be transferred to any part of this same circuit. as regards lighting, it is preferable to employ alternating current dynamo machines; yet there is nothing to prevent the use of continuous current ones, provided that there is an arrangement that permits of constantly opening and closing this same circuit. that portion of the line which is placed under ground is insulated in the ordinary way at the places where it is necessary. as for the underground circuit and the induction coils connected therewith, these are protected against all external influence, and are at the same time insulated very economically by covering them with a coat of very fine silicious sand mixed with asphalt. it is only necessary to inspect the annexed figure to get an accurate idea of this system of distribution. c represents the building in which the generator of electricity, d, is placed; b, the public street, and q the house of a subscriber. the principal line, e, starts from the terminals, _a, b_, of the machine, passes through the primary bobbins, g, and is closed through the earth at f. it will be seen that the primary current communicates through _d_ and _c_ with the internal winding of the bobbins, g, while the secondary currents, h, are connected through _e_ and _f_ with the external winding. the same arrangement is repeated for the tertiary currents, m, and the quaternary ones, _o, p_. in the annexed example all the lines that run parallel with the axis of the streets are closed through the earth, while those that have a direction perpendicular thereto enter the houses of subscribers and form a closed circuit. in the interior of these houses the wires, as well as the induction coils, are insulated and applied to the walls. at q is represented the arrangement that would have to be adopted in the case of a structure consisting of a vestibule, _r_, and two rooms, _s_, lighted by two electric lamps, r. in the portion of the figure situated to the left it is easy to see the process employed for insulating the line. a commencement is made by digging a ditch in the street and paving the bottom of it with bricks. upon these latter there is laid a mixture of sand and asphalt, and then the wires and bobbins are put in, and the whole is finally covered with a new insulating layer. it is a simple statement that we make here, and it is therefore not for us to discuss the advantages and disadvantages of the system. if we are to believe mr. enuma, the advantages are very numerous, to wit: ( ) the cables have no need of being of large size; ( ) the intensity is the same through the entire extent of the primary circuit, secondary one, etc.; ( ) the resistance is invariable in all portions of the line; ( ) the apparatus are independent of each other, and consequently there may be a disturbance in one or several of them without the others suffering therefrom; ( ) either a strong or weak luminous intensity may be produced, since, that depends only upon the size of the coil employed; ( ) there is no style of lamp that may not be used, since each lamp is mounted upon a special circuit; ( ) any number of lamps may be lighted or extinguished without the others being influenced thereby; ( ) when a fire or other accident happens in a house, it in no wise interferes with the service in the rest of the line; ( ) the system could, were it required, be connected with any other kind of existing line; and ( ) the cost of installation is infinitely less than that of a system of gas pipes embracing the same extent of ground.--_la lumiere electrique._ * * * * * electricity applied to the study of seismic movements. italy, with her volcanic nature, has very naturally made a specialty of movements of the ground, or seismic perturbations. so the larger part of the apparatus designed for such study are due to italians. several of these instruments have already been, described in this journal, and on the present occasion we shall make known a few others that will serve to give an idea of the methods employed. for the observation of the vertical and horizontal motions of the ground, different apparatus are required. the following is a description of those constructed for each of such purposes by the brassart brothers. [illustration: fig. .--apparatus for the study of horizontal seismic movements.] _apparatus for studying horizontal movements._--a lever, (fig. ), movable about a horizontal axis, carries a corrugated funnel, _i_, at one of its extremities. at the other extremity it is provided with a counterpoise which permits of its being exactly balanced, while not interfering with its sensitiveness. [illustration: figs. and .--details of the apparatus.] the opening of the funnel passes freely around a column, _v_ (fig. ), upon which is placed in equilibrium a rod that terminates in a weight, p. the corrugations of the funnel carry letters indicating the four cardinal points, and the funnel itself is capable of revolving in such a way that the marked indications shall always correspond to the real position of the cardinal points. when a horizontal shock occurs, the weight, p, falls in a direction opposite thereto, and into one of the corrugations, where it rests, so that the direction of the shock is indicated. but, in falling, it causes the lever, f, to tilt, and this brings about an electric contact between the screw, _h_, and the column, _n_, which sends a current into the electro, e, so that the armature of the latter is attracted. in its position of rest this armature holds a series of parts, s, a, l, which have the effect of stopping the pendulum of a clock placed upon the same apparatus. at the moment, then, that the armature is attracted the pendulum is set free and the clockwork is started. as the current, at the same time, sets a bell ringing, the observer comes and arranges the apparatus again to await a new shock. knowing the hour at which the hand of the clock was stopped, he sees how long it has been in motion again and deduces therefrom the precise moment of the shock. the small rod, _f_, which is seen at the extremity of f, is for the purpose of allowing electricity to be dispensed with, if need be. in this case the screw, _h_, is so regulated that f descends farther, and that _f_ may depress the armature of the magnet just as the current would have done. [illustration: fig. .--apparatus for the study of vertical movements.] _apparatus for the study of vertical movements._--in this apparatus (fig. ), the contact is formed between a mercury cup, t, and a weight, d. the cup is capable of being raised and lowered by means of a screw, so that the two parts approach each other very closely without touching. at the moment of a vertical shock a contact occurs between the mercury and weight, and there results a current which, acting upon the electro, e, frees the pendulum of the clock as in the preceding apparatus. in this case, in order that the contact may be continuous and that the bell may be rung, the piece, a, upon falling, sets up a permanent contact with the part, _a_ (fig. ). [illustration: fig. .--brassart's seismic clock.] _brassart's seismic clock._--this apparatus is designed for being put in connection at a distance with an indicator like the ones just described. it is a simple clock to which a few special devices have been added. seismic clocks may be classed in two categories, according as they are stopped by the effect of a shock or are set running at the very instant one occurs. the messrs. brassart have always given preference to those of the second category, because there is no need of watching them during a seismic calm, and because they are much more easily constructed. it is to this class, then, that their seismic clock belongs. it is capable of being used for domestic purposes in place of any other clock, and of becoming a seismoscopic clock as soon as it is put in electric communication with the seismic telltales. to the cross-piece that holds the axle of the drums the inventors have added (fig. ) a support formed of a strip of brass, s, with whose extremity is jointed (at the lower part) a double lever, a. this latter is held in a horizontal position by a small counterpoise, _i_, so that the finger at the opposite extremity shall prevent the pendulum, p, from swinging. to keep the latter in a position of rest a bent lever, _n n'_, is jointed to the upper part of the support, s. the longer arm, _n'_, of this lever is bent forward at right angles, so that it may come into contact with and repel the small rod of the pendulum as soon as the lever has been lifted by means of a small cord which is connected with the larger arm, _n_, and runs up to a small hook, from whence it descends and makes its exit under the clock-case. in order to stop the clock, then, it is only necessary to pull on this cord slightly, when, by moving the pendulum to the left, it will thrust it against the inclined plane of the finger of the lever arm, a. it is clear that the extremity of the pendulum, upon striking against the finger, will depress it slightly and go beyond the projection against which it remains fixed owing to the counterpoise, _i_. the fever, _n n'_, is brought back to its position of rest by means of a small counterpoise at the extremity of the arm, _n_. when the lever, a, is depressed, the pendulum escapes and sets the clock running. this depression is effected by means of an electro-magnet, e, whose armature, which is connected with the rod, _t, t_, lifts the arm, _i_, of the lever, and depresses a. the wires of the two bobbins of the electro-magnet end in two clamps, and . the second of these latter is insulated from the clock-case. both communicate with the extremities of the circuit in which is interposed the seismic telltale that brings about a closing of the current. having noted the position of the hands on the dial when the clock was running, one can deduce therefrom the moment at which the shock occurred that set the clock in motion. in addition to the parts that we have described, there are other accessory ones, r r_r_, and a third clamp, , which constitute a sort of rheotome that is designed to keep the circuit closed after the momentary closing that is produced by the telltale has occurred. this little mechanism is indispensable when the disturbed telltale has also to act upon an electric bell. this rheotome, which is very simple, is constructed as follows: a small brass rod, r, which is screwed to the support, s, carries at its left extremity a brass axis, x, which is insulated from the rod, r, by means of an ivory piece. toward the center of this small rod, the bent lever, _r_, carries a small arm that is bent forward, and against which abuts the axis of the pendulum, thus causing it to be thrust toward the left when the pendulum is arrested by the projection of the finger, a. as soon as the pendulum is set free, the lever, _r_, redescends and places itself against the axis, x. this latter communicates with clamp , which is insulated, while the rod, r, communicates with clamp . the external communications are so arranged that the circuit in which the bell is interposed remains definitely closed when the lever, _r_, is in contact with the rod, x. [illustration: fig. .--rossi's tremitoscope.] _rossi's tremitoscope._--this instrument (fig. ) unites, upon the same stone base, three different arrangements for showing evidences of trepidations of the earth. on one side we find (protected by a glass tube) a weight suspended over a mercury cup by a spring, and designed to show vertical motions. the two other parts of the apparatus are designed for registering horizontal motions. the first is a pendulum which causes a contact with four distinct springs, and whose movements are watched with a spy-glass. the second is a steel spring which carries at its upper part a heavy ball that vibrates at the least shock. this ball is provided with a point which is movable within a second ball, so that its motion produces a contact. all these different contacts are signaled or registered electrically. [illustration: fig. .--scateni's seismograph.] _scateni's registering seismograph._--this apparatus, which is shown in figs. and , consists of two parts--of a transmitter and of a registering device. [illustration: fig. .--registering apparatus.] the transmitter consists of a glass vessel supported upon a steel point and provided beneath with a platinum circle connected with a pile. all around this circle are four strips of platinum, against one of which abuts the circle at every movement of the glass. each strip of platinum communicates, through a special wire, with one of the electro-magnets of the registering device (fig. ). this latter consists of an ordinary clock that carries three concentric dials--one for minutes, one for hours, and one for seconds. in a direction with the radii of these dials there are four superposed levers, each of which is actuated by one of the electros. on another hand, each dial is divided into four zones that correspond to the four cardinal points. when a shock coming from the north, for example, produces a contact, the corresponding electro is affected, and its lever falls and marks upon each of the dials a point in its north zone. we thus obtain the exact hour of the shock, as well as its direction. as may be seen, the apparatus, as regards principle, is one of the simplest of its kind.--_la lumiere electrique._ * * * * * new accumulators. [illustration: fig. .--arnould & tamine's accumulator.] in messrs. arnould and tamine's accumulators, shown in fig. , the formation is effected directly by the current, as in the planté pile, but the plates are formed of wires connected horizontally at their extremities by soldering. these plates are held apart either by setting them into paraffined wooden grooves at the ends of the trough or by interposing between them pieces of paraffined wood. [illustration: fig. .--barrier & tourvielle's electrodock.] in messrs. barrier and tourville's _electrodock_ (fig. ) the plates are formed of concentric leaden tubes fixed into a wooden cover. these tubes are threaded internally and externally, and the grooves thus produced are filled with a peculiar cement composed of litharge, powdered charcoal, and permanganate of potash, triturated together, sifted, and then mixed with glucose or sugar sirup so as to make a paste of them. this mixture forms a cement that is very adhesive after, as well as before, the electrolytic action. [illustration: fig. .--kornbluh's accumulator.] in kornbluh's accumulators the plates consist of ribbed leaden gratings between which is compressed red lead prepared in a peculiar manner, and constituting, hours after formation, a compact mass with the lead. the tangs of the plates are widened so as to touch one another while leaving a proper distance between the plates themselves, and are hollowed out for the reception of a rod provided at its extremities with a winged nut and jam nut for passing them up close to one another. the plates, properly so called, are held apart by rubber bauds. the glass vessels are placed in osier baskets.--_la lumiere electrique._ * * * * * industrial model of the reynier zinc accumulator. the three models of a secondary battery that i recently made known to the readers of this journal have been the object of continuous experiment. conformably to the provisions of theory, the zinc accumulator has shown itself practically superior to the two others, and i have therefore chosen this type for getting up an industrial model, which is shown in the annexed cut. the accumulator contains four planté positives, having a wide surface, and three negatives constructed of smooth sheets of lead covered with zinc by the electrolysis of the acidulated solution of zinc sulphate in which the couple is immersed. accidental contact with the interior of the pile is prevented by glass tubes fixed to the negatives by means of leaden bands. the seven electrodes are carried by as many distinct crosspieces of paraffined wood, which rest upon the edges of the trough and hold the plates at a certain distance from the bottom. these various crosspieces, which touch one another, take the place of a cover. each plate is provided with a terminal. the four positive terminals are all on the same side, and the three negatives are on the opposite side. two brass rods ending in a wire-clamp connect the respective terminals of the same name. the trough consists of two oblong wooden receptacles, one within the other, and having a play of several millimeters. this space is lined with a tight, elastic, insulating cement having tar for a base. [illustration: reynier's zinc accumulator. (one-fifth actual size.)] the careful insulation of the trough and all parts of the apparatus, and the purity of the metal and its amalgamation, reduce the local attack of the zinc to almost nothing. so the coefficient of restitution is now comparable with that of accumulators of the planté type. the following are the principal numerical data of the new zinc accumulator. physical data. e. electromotive force. . volts. r. mean resistance. . ohm. i. normal intensity of the discharge current. amperes. i. intensity of the charge current. to amperes. q. capacity of accumulation after hours' formation. , couples. data concerning construction. efficient surface of the positive electrodes. square dec. efficient surface of the negative electrodes. square dec. weight of the positive electrodes. . kilogrammes. weight of the negative electrodes. . kilogrammes. weight of the trough. . kilogrammes. weight of the liquid. . kilogrammes. weight of the attachments. . kilogrammes. weight, total. . kilogrammes. the total electric work stored up is , kilogrammeters, or , kilogrammeters per kilogramme of accumulator. theory indicates that a zinc accumulator might store up as much as , kilogrammeters per kilogramme. if the present model gives half less, it is because i have purposely exaggerated the solidity of the trough and the mass of the electrodes. it should be remarked that this capacity of , kilogrammeters per kilogramme is much greater than that of any other accumulator constructed in france. the new model possesses, then, despite the size of the positives and the box, a relative lightness that will permit it to take a place upon electric locomotives as well as in fixed installations. independently of their use as accumulators, secondary zinc batteries may be utilized as regulating voltameters in lighting by incandescence, for deadening piston strokes, attenuating the irregularities in speed, and covering accidental stoppages.--_e. reynier, in la nature._ * * * * * the history of a lightning flash. by w. slingo. lately we have all felt, i doubt not, a considerable amount of interest in the various phenomena attending this summer's unusually heavy thunderstorms, accompanied, as they have been, by vivid lightning discharges of a more or less hurtful nature. the list of disasters published in _knowledge_, no. , might be very materially augmented were we to record such damage as has been wrought since that list was compiled. there is not, i suppose, in the mind of any intelligent man at the present day a doubt as to the electrical origin of a lightning flash. the questions to be considered are rather whence comes the electricity, and in what way is the thunderstorm brought about. in attempting to answer these questions, sight must not be lost of the fact that the very nature of electricity is in itself almost sufficient to baffle any effort put forth to ascertain from lightning, as such, its whence and its whither. it is possible, however, with the aid of our knowledge of static electricity, to arrive at hypotheses of a more than chimerical nature. in the first place, that our sphere is a more or less electrified body is generally admitted. more than this, it is demonstrated that the different parts of the earth's surface and its enveloping atmosphere are variously charged. as a consequence of these varying charges, there is a constant series of currents flowing through the various parts of the earth, which show themselves in such telegraph wires as may lie in the direction followed by the currents. such currents are known as earth currents, and present phenomena of a highly interesting nature. but, apart from these electrical manifestations, there is generally a difference of electrical condition between the various parts of the earth's surface and those portions of the atmosphere adjacent to or above them. inasmuch as air is one of the very best insulators, this difference of condition (or potential) in any particular region is in most cases incapable of being neutralized or equilibrated by an electric flow. consequently the air remains more or less continually charged. with these points admitted as facts, the question arises, whence this electricity? there have been very many and various opinions expressed as to the cause of terrestrial electricity, but far the greater portion of such theories lack fundamental probability, and indicate causes which cannot be regarded as sufficiently extensive or operative to produce such tremendous effects as are occasionally witnessed. i take it that we may safely regard the evolution of electricity as one of the ways in which force exhibits itself, that, in other words, when work is performed electricity may result. when two bodies are rubbed together, electricity is produced, so also is it when two connected metals are immersed in water and one of them is dissolved, or when one of the junctions of two metals is raised to a higher temperature than the other junction. i will go further than this, so far, in fact, as to maintain that there is a reasonable ground for supposing that every movement, whether it be of the mass or among the constituent particles, is attended by a change of electrical distribution; and if this is true, it may easily be conceived that inasmuch as motion is the rule of the universe, there must be a constant series of electrical changes. now, these changes do not all operate in one direction, nor are they all of similar character, whence it is that not only are there earth currents of feeble electro-motive force, but that this e.m.f. is constantly varying, and that, furthermore, electricity of high e.m.f. is to be met with in various parts of the atmosphere. with earth currents we have here very little to do. the rotation of the earth is in itself sufficient to generate small currents, and the fact that they vary in strength at regular periods of the day and of the year enforces the suggestion that the sun exerts considerable electrical influence on the earth. letting it be granted, however, that the earth is variously charged, how comes it that the air is also charged, and with electricity of greater tension than that of the earth itself? it was pointed out by sir w. grove that if the extremities of a piece of platinum wire be placed in a candle flame, one at the bottom and the other near the top, an electric current will flow through the wire, indicating the presence of electricity. if an electrified body be heated, the electricity escapes more rapidly as the temperature rises. if a vessel of water be electrified, and the water then converted into steam, the electric charge will be rapidly dissipated. if a vessel containing water be electrified, and the water allowed to escape drop by drop, electricity will escape with each drop, and the vessel will soon be discharged. we regard it as an established fact that the earth has always a greater or less charge; whence it is safe to assume that in the process of evaporation which is going on all over the surface of the globe, more particularly in equatorial regions, every particle of water, as it rises into the air, carries with it its portion, however minute that portion may be, of the earth's electric charge. this small charge distributes itself over the surface of the aqueous particle, and the vapor rises higher and higher until it reaches that point above which the air is too rare to support it. it then flows away laterally, and as it approaches colder regions gets denser, sinking lower and nearer to the earth's surface. the aqueous particles becoming reduced in size, the extent of their surfaces is proportionately reduced. it follows that as the particles and their surfaces are reduced, the charge is confined to a smaller surface, and attains, therefore, a greater "surface density," or in simpler language, a greater amount of electricity per unit of surface. electricity, as above set forth, is in what is known as the "static" condition (to distinguish it from electricity which is being transferred in the form of a current), when it has the property of "repelling itself" to the utmost limits of any conductor upon which it may be confined. this will account for the charge finding its way to the surface of the water particles, and will furthermore account for the greater density of the charge as the particle gets smaller and has the extent of its surface rapidly diminished. it may be mentioned that the surface of a sphere varies as the cube of its radius. returning to the discussion of the state of affairs existing when the particles have reached their highest position in the atmosphere, we may imagine that they set themselves off on journeys toward either the north or the south pole. as they pass from the hotter to the colder regions, a number of particles coalesce; these again combine with others on the road until the vapor becomes visible as cloud. the increased density implies increased weight, and the cloud particles, as they sail poleward, descend toward the surface of the earth. assuming that a spherical form is maintained throughout, the condensation of a number of particles implies a considerable reduction of surface. thus, the contents of two spheres vary as the cubes of their radii, or eight (the cube of ) drops on combining will form a drop twice the radius of one of the original drops. we may safely conceive hundreds and thousands of such combinations to take place until a cloud mass is formed, in which the constituent parts are more or less in contact, and, therefore, behave electrically as a single conductor of irregular surface, upon which is accumulated all the electricity that was previously distributed over the surfaces of the millions of particles that now compose it. the tendency of an electric charge upon the surface of a conductor is to take upon itself a position in which it may approach nearest to an equal and opposite charge; or, if possible, to attain neutrality. if, then, a cloud has a charge, and there is no other cloud above or near it, the charge _induces_ on the adjacent earth surface electricity of the opposite kind. thus, assuming the cloud to be charged with positive electricity, the subjacent earth will be in the negative state. the two electricities[ ] exert a strong tendency to combine or to produce neutrality, whence there is a species of stress applied to the intervening air. possibly the cloud will be drawn bodily toward the earth more or less rapidly, according as the charge is great or small. or, on the other hand, the cloud may roll on for leagues, carrying its influence with it, so that the various portions of the earth underneath become successively charged and discharged as the cloud progresses on its journey. [footnote : we may speak of two electricities or two electric states without necessarily implying adherence either to the single or the double "fluid" theory. whether electricity be of two kinds or no, the fact remains that there are two conditions, and all the features of this paper may be explained with equal facility by the supporters of either hypothesis.] should the cloud be near the earth, or should it be very highly charged, the tension of the two electricities may be so great as to overcome the resistance of the intervening air; and if this resistance should prove too weak, what happens? how does the discharge show itself? it takes place in the form of a lightning flash, and passing from the one surface to the other--or, maybe, simultaneously from both--produces neutrality more or less complete. there has recently been a little discussion in these pages on the subject of lightning, some having stated that they discerned the discharge to take place upward--that is, from the earth toward the cloud. i will not venture so far as to say whether or not the direction of the discharge is discernible; possibly the flash may sometimes be long enough to enable one to tell; but i have never so seen it, and have always looked upon the eye as a deceitful member--very. "the lightning flash itself never lasts more than / of a second." it is, however, just as likely that a discharge may travel upward as downward. what controls the discharge? does the quality of the charge?--that is to say, is the positive or the negative more prone to break disruptively through the insulating medium? investigations with geissler's and other tubes containing highly rarefied gases have made it tolerably clear that there is a greater "tearing away" influence at the negative than at the positive pole, and if two equal balls, containing one a positive and the other a negative charge, be equally heated, the negative is more readily dissipated than the positive. but, so far as we at present know, this question enters into the discussion scarcely, if at all. our knowledge seems rather to point to the substances upon which the charges are collected. the self-repellent nature of electricity compels it to manifest itself at the more prominent parts of the surface, the level being forsaken for the point. the tension of the charge, or its tendency to fly off, is proportionately increased. and if at a given moment the tension attains a certain intensity, the discharge follows, emanating from the surface which offers the greatest facilities for escape. the earth is generally flatter than the cloud, whence, in all probability, the discharge more frequently originates with the cloud. should a lightning flash strike the earth and produce direct neutrality, it is possible that no damage will result, although this again is not always certain, because when the cloud charge acts inductively on the earth it produces the opposite (say negative) charge on the nearer parts, the similar (or positive) state is also produced at some place more or less distant. sometimes this "freed" positive (which, by the way, accumulates gradually and physiologically imperceptibly) is collected at some portion of the earth's surface. when the negative is neutralized by the discharge, the freed positive is no longer confined to a particular region, but tends to dissipate itself, and a shock may be felt more or less severely by any person within the region. or, again, a similar shock may be experienced by a person standing within the negative zone on the neutralization of the charge. i may take the opportunity here to mention a highly interesting and instructive incident observed on local telegraph circuits during a thunderstorm. the storm may be taking place at some distance from the point of observation. the electrified cloud induces the opposite charge beneath it, the similar charge being repelled. it is noticeable that the needle of a galvanometer, starting from the middle position, goes gradually over to one side, eventually indicating a considerable deflection. suddenly, owing apparently to a lightning discharge some distance away, the force which caused the deflection is withdrawn, and the needle rebounds with great violence to the opposite side. in a short time, the cloud becoming again charged on its under surface, and recommencing its inductive effect upon the adjacent earth, the needle starts again, and goes through the same series of movements, a violent counterthrow following every flash of lightning. if we can so far control our imagination, we may conceive the earth to be one large insulated conductor, susceptible to every influence around it. if then the earth, as a mass of matter, behaves as above indicated, there is no plausible reason for declining to regard any other large conducting mass in a similar light, and as a body capable of being subjected more or less completely to the various impulses affecting the earth. in other words, a large mass of conducting material, partially or perfectly insulated, is, during a thunderstorm, in considerable danger. with this portion of the subject i shall, however, deal more fully when discussing the merits of lightning protectors. lightning discharges do not take place between cloud and earth only, but also, and perhaps more frequently, between too oppositely charged clouds. we then get atmospheric lightning, the flash often extending for miles. this form of lightning is harmless, and in all probability what we see is only a reflection of the discharge. the oft-told tale of the lightning flying in at the window, across the room, and out of the door, or up the chimney, is all moonshine, and before dealing with lightning protectors i intend to expose some of the fallacies concerning lightning. were the discharge to pass through a house, it would infallibly leave more decided traces and do more damage than simply scaring a superstitious old lady now and again. many people are often and unnecessarily frightened during a thunderstorm, but it may be safely predicted that a person under a roof is infinitely safer than one who is standing alone on level ground, and making himself a prominence inviting a discharge. rain almost invariably accompanies the discharge, and the roof and sides of the house being wet, they form a more or less perfect channel of escape should a flash strike the building.--_knowledge._ * * * * * researches on magnetism. by m. duter. if we place a thin plate of steel in a uniform magnetic field, so that the lines of force of the field may be normal to the surface of the plate, we have a very flat magnet, the two faces of which are the two polar surfaces. the magnetic distribution thus obtained seems to disappear when the plate is no longer in the field. the following experiments show that this disappearance is not complete. i made use of plates of tempered steel of millimeter in thickness, and varying in diameter from . to . meter. with these plates i formed cylindrical batteries. in some of these batteries the plates are directly in contact, and in others they were separated by leaves of pasteboard, the thickness of which varied from that of the thinnest paper to . meter. the batteries were placed in the central portion of a very powerful magnetic field, and after they have been taken out they formed perfectly regular permanent magnets. the supporting power of these magnets was the greater the nearer its constituent plates were to each other. in a battery of plates, touching each other directly, and strongly pressed into a brass cylinder, the portative force at each extremity rose to grammes. this first result having been obtained, i dismounted the batteries, plate by plate, taking care to mark the upper and under side of each. i found then that each plate retained only an excessively slight magnetism. yet each of them still constituted a flat magnet, of which the two faces are the polar surfaces; for on rebuilding the battery it gave again a perfectly regular magnet, though weaker than it was at first. the separation of the magnet into its constituent plates, and its reconstruction, maybe repeated indefinitely.--_comptes rendus._ * * * * * dr. t. tommasi (_cosmos les mondes_) notes that the thermic constant of thallium is exactly the mean of the thermic constants of potassium and lead, the two metals which it most resembles in its chemical character. * * * * * improved gas light buoy. [illustration: gas light buoy.] the accompanying engravings represent a light buoy made by the pintsch's patent lighting company for the river humber. the chief dimensions of the buoy are given in the engraving, which also shows that the gas holder is placed within the boat in such a way as to be protected from blows likely to cause any leakage. the buoy has a special form to meet its requirements as a lightship, and the conditions of its employment is the fast tidal current of the river. it was designed by mr. c. berthon, of westminster, and is intended to carry a six months' supply of gas, the burner, regulator, and lamp being on the well known pintsch system. the hull is formed of / inch plate, feet inches total length, and feet beam at the line of flotation. the laps of the plates are inches wide, and riveted with / inch rivets, spaced - / inch apart center to center. the keel and stem are both in one piece, as shown, and to this the garboard strake is to be fastened. the bilge pieces are riveted on to the bilge, and made of inches by - / inches by / inch t-iron. a wooden fender, inches by inches wood, is fitted on both sides of hull, running from stern to stern, by inches by - / inches by / inch l-iron top and bottom with the sheer as shown. the hull from water line falls in as shown, so as to describe at midships an arc of feet inches, and a circular deck of / inch plate is riveted on the hull. there are two man-holes, each inches diameter in the clear, placed in end plates of the circular deck as shown, and provided with covers / inch thick, secured by twenty screws / inch diameter. the edge of each manhole is stiffened by a welded iron ring. the surface of the mooring link that comes in contact with the shackle and mooring chain is steeled. the gas holder rests upon a plate bent up on each side, and riveted to the keelson, and is prevented from rolling by four gusset plates, with two short pieces of angle iron riveted thereto at the ends and coming in contact with the holder, and at the ends by angular plates, and angle iron riveted on each side and riveted to the keelson. the superstructure consists of four legs of angle iron - / inches by - / inches by / inch, the upper ends of the legs being attached to a square flanged plate for supporting the lighting apparatus. four wooden battens of pitch pine, inches by - / inches, and bolted on to each cant of the angle iron superstructure, with / inch galvanized iron bolts and nuts. [illustration: gas light buoy.] * * * * * project for a roadstead at havre. the present port of havre is absolutely insufficient to answer the ever increasing requirements of commerce. its entrance, which is too narrow and not deep enough, does not permit steamers to go in, come out, and perform their evolutions with the rapidity required by our epoch. so they are gradually abandoning our port, and going to load and unload at anvers and elsewhere. a large number of wise heads, who are anxious about the future of this port and our national interests, have devoted themselves to finding a means of enlarging it, not by dredging _new_ basins, which would prove ruinous to the budget and useless in twenty years, but by installing a true roadstead at the entrance to the present basins. [illustration: fig .--plan of the projected roadstead at havre.] upon the maps of the hydrographic service may be seen, under the name of the little roadstead, a vast extent of sea nearly two kilometers wide by three to four in length, bounded upon one side by the heights of heve and st. adresse, and upon the other by the rocky line of eclat and of the heights of the roadstead (fig. ). this little roadstead, so called, in order to become a genuine one, would have to be protected against the great waves of the open sea. to thus protect it, to close it as quickly and as cheaply as possible--that is the problem. in , charles de massas presented a project (the first in order of date), which consisted in constructing upon the eclat reef a semi-lunate dike, and a breakwater at cape heve. moreover, upon the emergent parts of the eclat reef and heights of the roadstead he proposed to erect two forts. [illustration: fig. .--lewis' floating breakwater.] the defense of the port of havre is a very important question, and one that appears to be completely abandoned. since engineer degaulle in advised the erection of a fort upon the eclat, and requests have periodically been made and projects drawn. the requests are forgotten, but the drawings are in the ministers' portfolios, and if france should to-morrow have a war with a maritime power our great northern port might be destroyed and burned by the smallest squadron. some years after massas' project, two officers, deloffre and bleve, and an engineer named renaud, received a commission to search for a means of closing a portion of seine bay. these gentlemen advised the erection of two dikes, one on the eclat shoal in the very axis of this reef, and the other at heve. between these two masonry dikes was to be placed a floating breakwater. this project, which was submitted to admiral de hell in , had a favorable reception, and the admiral especially applauded the trial of breakwaters, "which were much talked of in england, although the effects that they might produce were not well known." deloffre, bleve, and renauds' project comprised two forts--one to the north and the other to the south of the roadstead. for a long time nothing more was said about it, and it is only during recent years, when the peril has become imminent for havre (threatened as it is of being abandoned even by the french transatlantics), that the question has again became the order of the day. [illustration: fig. .--froideville's floating breakwater.--end view.] mr. bert, a merchant, would protect the little roadstead by means of two jetties, , and , meters in length, built, one of them upon the eclat and the other upon the eminences of the roadstead. these would be constructed by forming a foundation of loose rocks, and using earth and brick above the level of the water. mr. vial has likewise proposed a rockwork of , meters in length, to form a dike meters in height and width, whose platform would be on a level with the highest tides. next comes the more recent project of mr. coulon. seeing that it is the deposits of the ocean and not those of the seine that accumulate upon the estuary, mr. coulon advises the construction of a dike about , meters in length, starting from the havre jetty, and ending at the southwest extremity of the shoals at the roadstead heights, and a second one returning toward the northwest, of from to , meters. a third and very long one of not less than kilometers would be built from honfleur to the ratier shoals. this latter one, in contracting the bay, would contribute to increase the force of the current, which, throwing back at the ocean its mud and pebbles, would give us the depths of and meters indicated on the map of beautemps-beaupre. this year, again, two projects have arisen; one of them due to mr. thuillard-froideville, and the other to mr. hersent. according to mr. hersent, it would be necessary to surround the little roadstead with an insubmersible dike built upon the rocky shoals, which would begin at cape heve (which it would consolidate) and end opposite the entrance to the port at , meters from the jetties. through it there would be five passages. afterward another dike would be constructed, starting from the shore and running to meet the jetty designed to inclose the little roadstead. on turning the angle at which it met the jetty it would be continued as far as to berville. finally, a third dike, running from honfleur to berville, would complete the system. mr. hersent's project, which is one of the most remarkable of those that have been proposed, has one fault, and that is that it would require twelve years of work, and cost million francs. mr. thuillard-froideville, completely renouncing masonry dikes as being too costly and taking too long to construct, proposes to inclose the havre roadstead by means of floating breakwaters. as we have already seen, the use of these between cape heve and the eclat shoals had already been proposed in . as the project was abandoned, the models of these breakwaters are rare. in bouniceau's "marine constructions" we find a curious figure, a sort of open framework of clumsy form anchored in a singular manner, and surmounted by rooms for watchmen, semaphores, posts for the shipwrecked, etc. it is, indeed, the most complicated and most impracticable type that could be imagined. mr. lewis' model, which was exhibited last year at the international fisheries exhibition, was, on the contrary, one of the simplest. it consisted of a strong piece of wood of nearly triangular section, the sharpest angle of which, being turned oceanward, was designed to cut the waves and cause them to break over it (fig. ). if, by favor of divine providence, this breakwater, which presents absolutely plane surfaces to the shock and pressure of the waves, is not broken to fragments in the first tempest, it will certainly acquit itself of the _role_ for which the inventor destined it. when we have a system of resistance to the sea, anchored and facing a certain direction, and consequently not being able to revolve around its axis as vessels do, care must be taken not to give it entire surfaces. [illustration: fig. .--froideville's breakwater.--mode of joining the parts.] mr. froideville's breakwater consists of a framework meters in length, and in height and width, and having the form of an irregular -sided prism (fig. ). the smallest side of the prism is designed to serve as a flat keel. the axis is formed of a metallic float, from whence start radii that form the skeleton of the framework, and that are designed for connecting the center with five long spruce beams that form the angles of the prism. to these beams are affixed the cross pieces that form the openwork sides. five long pieces of wood parallel with the beams, but not so strong as they, protect the cross pieces and secure them against breakage in the middle. all the angles of the breakwater and all points of juncture of the pieces are protected with iron, and it is in order to counterbalance the weight of all this iron that the central float is used. parallel with this first breakwater, there are two other and smaller ones, which are designed for reducing the effect of rolling as much as possible. reduced to a single float, the breakwater might remain under the waves too long, but, owing to the two others, it rights itself, warps around, and always presents the spur of its sharp roof to the wave. in order to prevent the breakwaters from clashing against each other, they are united end to end in a very simple and ingenious manner. from each of them there starts a deeply inserted iron bar which terminates in a journal that permits the breakwater to oscillate. between these two bars there is a sort of swivel, whose pieces, in playing upon one another, give the breakwaters elasticity, while always holding them apart (fig. ). from each side of the swivel start the branches of a stirrup iron to which the anchorage chain is attached. this latter is of steel, without solderings, and it is so perfectly constructed that no breakage need be feared. to the other extremity of the chain is attached an anchor having two flukes, which both engage with the bottom. mr. froideville proposes to set up two lines of these breakwaters, for a length of about ½ kilometers, starting at the north from cape heve, taking in depths of meters (the best that are found in the little roadstead), passing in front of the eclat shoal and the heights, and ending opposite the entrance of the present port. the first row is designed for breaking the force of the waves, and the second for lending its aid in times of high tempests, and stopping the surge that has escaped from the first. the extreme simplicity of this project has permitted its promoter to affirm that in a few months, and with nine millions, he can inclose the havre roadstead. the little roadstead, being thenceforward protected, will become an excellent port of refuge in bad weather. in addition, a system of lighters, or, better, a few floats connected with the shore and forming a rock, will permit vessels to take on their cargoes with great rapidity. mr. froideville's project presents the further advantage of rendering it easier to put the port of havre quickly in defense. a certain number of floating batteries, anchored behind the breakwaters and protecting the advances of torpedo boats by means of their firing, would make a formidable defense. not having to perform any evolutions, they might without danger be invested with armor plate thicker than that of ordinary ironclads. in order to complete the system, there might be erected upon the eclat shoal an ironclad fort like that which defends the entrance of portsmouth. an english chronicler of the fourteenth century, in speaking of his country, places it above all others, and declares that men are handsomer, whiter, and purer blooded there than elsewhere, and he says that this is so "because it is so." we would not like to imitate his naive reasoning, and yet, for defending the very original system proposed by mr. froideville, we have only our conviction, which we share, moreover, with a large number of sea-faring men and engineers. mathematics are powerless to predict to us with accuracy the manner in which the floating breakwaters will behave, but experiment remains. let the promoter of the project, then, be given authority to inclose a few hundred meters, and if, as we suppose, the breakwaters shall remain immovable in a northwester, a maritime revolution will have been brought about.--_la nature._ * * * * * improved catch basin. in , m. bacle published in _le génie civil_ a study of the sewer systems in some of the large foreign cities. there may be found there a description of the liernur system at amsterdam, leyden, and dordrecht, in holland, and in certain cities of germany and the united states. [illustration: improved catch basin.] this system consists in the employment of two distinct systems of ducts, one for the discharges from water-closets and the other for household wastes, rain water, and the discharges from factories when sufficiently purified. this arrangement allows the employment of sewers of small section, provided that it shall be unnecessary to enter them for the purpose of cleansing them. it has been necessary, therefore, to provide inlets with a separating apparatus called "gully" or "catch basin," which retains as completely as possible all solid matter, mud, excrement, and _debris_ of every kind which maybe floated in by street washing or by rain-water, and which may be capable of causing stoppages in the sewers, the choking up being followed by fermentation and the emanation of noxious vapors. m.c. pieper of berlin suggests a device for a catch basin, which appears to meet the requirements. it is in the form of a cylindrical metal box, enlarged in its upper section to receive a filtering cylinder of perforated sheet iron, which occupies almost the upper half of the device and rests upon the smaller lower part. the entire apparatus is covered by a movable funnel, through which enter water and any rubbish which it may carry with it. from one side a tube allows the liquid to be discharged, while a siphon placed on the opposite side serves the same purpose under certain circumstances, as will be explained. figure represents the apparatus discharging under normal conditions. the heavy matter, sand, stones, etc., falls to the bottom into a receptacle which can be lifted out from time to time and emptied. the lighter buoyant matters, straw, vegetable _debris_, paper, etc., remain at the surface, and are retained by the filter; the water passing through the holes in the sheet iron rushes in a filtered condition through the annular space which exists in the upper part between the two cylinders, and escapes by the waste-pipe when the water reaches a proper level. if at a given moment the quantity of water flowing in is too much to be discharged through this waste-pipe, the level of the water mounts in the cylinder until it reaches the top of the siphon. immediately the siphon comes into play and empties the upper part of the apparatus, and the filtered water contained in the annular space already mentioned quickly re-enters the cylinder through the perforated sheet iron, and in so doing cleans out the perforations with considerable energy. this second period is represented in the second figure. the mouth of the siphon being placed above the movable basket, the heavy matters contained in the latter are not in the least disturbed, and the metallic screen placed over the mouth prevents the entrance of any floating matters. when siphonic action ceases, the water in the short arm of the siphon empties itself into the main receptacle, and by so doing cleanses the screen. during a rain or the washing of the streets, the siphon can work in concurrence with the ordinary discharge-pipe. it is evident of course that these two--pipes can be placed on the same side of the apparatus, if this prove the most convenient arrangement. we will add that this apparatus can be applied not only to the liernur system, but also can be used for preventing the entrance of obstructions into sewers of the ordinary type, where the grade is small or where the quantity of water is insufficient; and if we adopt the system of "everything to the sewer," can we not find in the employment of this apparatus an element for the realization of the famous formula, "always in circulation, and never in stagnation?"--_le génie civil._ * * * * * [concluded from supplement no. , page .] water-power with high pressures and wrought-iron water-pipe. by hamilton smith, jr., m. am. soc. c.e. methods of conducting water and transmitting power. a description of the mode of using water-power for driving the north bloomfield tunnel in california, some years since, will give a good illustration of some of the advantages of the hurdy-gurdy. this tunnel was originally about , feet long, through a slate highly metamorphosed, with its general line passing under a good-sized stream, at a depth of about feet. there were eight working-shafts, each about feet deep, which, with the lower entrance or portal, gave sixteen working faces. diamond drills were used at the lower heading requiring power; the other fifteen headings were driven by hand-work. it was uncertain how much water would be encountered; but from the location, it was evident that a large quantity might be struck in any shaft, and hence it became necessary to have ample power at hand at each opening, in readiness for such an emergency. a pipe main was laid along the general line of the tunnel, with its pen-stock feet vertical above the surface at the upper shaft, and feet above the lowest shaft. it was made of single riveted sheet-iron, of no. (birmingham) gauge, in lengths of feet, put together stove-pipe fashion, with the joints made tight by cloth tarred strips and pine wedges. this pipe had a diameter of inches at the pen-stock, diminishing from this to , , and inches at its lower end. from it, short branches, inches in diameter, were extended to the several shafts. it was in one place carried across the stream by a light suspension bridge, some feet long, the trunk of a tree on each side forming a convenient tower. the aggregate length of the main and branches was , feet, with some , feet additional, for the branch to the diamond drills. the pipe was laid on the surface of the ground, its only protection being in places a couple of ½-inch planks tacked together, and placed over it; the range of temperature was from degrees to degrees fahr. (in the shade). it was inspected by the foreman of the tunnel-work as he daily walked over the line; besides the occasional driving of a few wedges and putting on a band or two, it gave no trouble from leakage, which probably for its entire length did not amount to more than an average of or cubic feet a minute; from time to time, a little sawdust was put into the pen-stock. three stop-gates were placed on the main, and a separate stop-gate at each shaft, operated by a fine-threaded screw, so that the water could be cut off when desired. [illustration: fig. .] fig. shows the arrangement of the machinery for hoisting and pumping, which was identical at the several shafts, except that the hurdy-gurdies varied from ½ feet in diameter at the upper shaft to feet at the lowest shaft. the water-wheel moved only in one direction; the pinion on the wheel-shaft drove the spur-wheel, to which the pitman of the pump-bob was attached. on the spur-wheel shaft was a friction-gear, driving the hoisting-reel; this reel was mounted on sliding blocks, so that hoisting was done by putting it in gear, the empty load being dropped by a friction-band. changing the size of the water-wheel as the pressure increased permitted the use of the same pattern of machinery at the different shafts. the water was brought to the wheel by a discharge-pipe, some nine feet long, having a vertical movement by ball-and-socket joint, so that at pleasure, by dropping the pipe, the machinery could be run at various speeds, or entirely stopped. at the end of this discharge-pipe was a cast tapered nozzle, about ½ inches in diameter, in which was inserted a ring of saw-plate steel having the desired diameter, and which was held in place by an annular screw-cap. by changing the ring, which only required a few moments' time, any desired amount of water, up to or cubic feet a second, could be discharged against the wheel. the stop-gate was left wide open while the machinery was running. the pumping was done by eighteen pumps, of cornish pattern; the largest amount of water pumped from any one shaft was something over cubic feet a minute; the power at hand, however, was ample to pump more than twice that quantity. it was rather curious at, this shaft to see more water coming from the pumps than was used on the wheel. the two diamond drills were driven by a small hurdy-gurdy set on the rear of the drill carriage. this, but at another tunnel, was afterward modified by placing a separate hurdy-gurdy on a sleeve on each drill-rod; the advance movement of the drill being given by hydrostatic pressure on an annular piston, thus doing away with all gearing. these eight sets of machinery were run for nearly ½ years' time; the only break being that of a spur-wheel, doubtless caused by the careless dropping of a steel bar between it and its pinion. aside from this accident, practically not a dollar was spent for repairs, and the machinery, including the pipe, was in about as good order when the tunnel was finished as when it was first erected. one man, on a twelve hour shift, operated the machinery at each shaft, besides dumping the cars; two men kept the pumps on the line in order, the principal work being in keeping the suction-pipes for the down-grade headings tight; thus a force of men was only required for the eight shafts. the cost of the pipe, gates, etc., when put in place, was $ , , and of the machinery about $ , . [illustration: fig. .] at the idaho gold quartz mine, situated near grass valley, california, water-power has been introduced during the past year ( ), taking the place of steam. the supply main is of wrought-iron, inches in diameter, , feet long, buried in the ground below frost-line. the joints, as a rule, are riveted together, with occasional lead joints to admit of slight movements in the pipe.[ ] the pipe was coated by placing each joint in a bath of boiling tar and asphaltum; to insure the most thorough coating, it is necessary to keep the pipe for ten or fifteen minutes in the boiling mixture. a cast-iron stop-gate is placed at the lower end of the main, and also one at each of the branches. cast-iron man-holes are attached to the main, which, although they have given no trouble in this particular case, are very objectionable for high pressures, as it is difficult to avoid ruptures with cast and wrought-iron combined, owing to the great difference in the elasticity of the two metals. the long seams of this pipe are double-riveted, and the round seams single riveted; at the lower end, iron of no. gauge is used. from the end of the main, the water is led to the several wheels by branches of smaller diameter. [footnote : with buried wrought-iron pipe this precaution is unnecessary, as the elasticity of the iron will admit of the movement due to changes of temperature, without injury to the rivets.] the water is delivered at the hoisting-wheel with a total head of . feet. for power and for mill uses, etc., the required supply is about cubic feet a second; this draught reduces the effective head to say feet. the work done consists in driving the following described machinery: a large air-compressor-- cylinders, double acting, air compressed to pounds--requiring about horse-power. a line of cornish pumps, forcing the water from a depth of , feet vertical; -inch plungers for upper feet, -inch plungers for lower feet, with -foot stroke, requiring from to horse-power. hoisting from a double-compartment shaft--two connected winding reels, moving separate cages--requiring horse-power, or more. a few small machine-tools and smithy forges, requiring or horse-power. a -stamp mill, with concentrating apparatus, etc., requiring about horse-power. the total amount of power required being say horse-power, for which seven pelton hurdy-gurdy wheels are employed. the power in all cases is transmitted by systems of manila rope belting; the rope is inches in diameter; the grooves in the sheaves or pulleys are slightly oval, so that the rope does not go quite to the bottom; the ropes are horizontal, and run very slack (no tighteners), with no appreciable slip; the splices are made very long, to obtain uniformity in diameter. [illustration: fig. .] this method of transmitting power appears to work most perfectly and has given excellent satisfaction. it is thought, at the idaho, to be greatly preferable to the gearing formerly in use when the works were driven by steam (for such work as pumping or hoisting, leather or rubber belting is never used), besides being much cheaper in first cost. the wheel driving the air-compressor is feet in diameter, running turns[ ] per minute, with - / -inch nozzle; three ropes are used from the wheel shaft to the counter-shaft, and six ropes from the latter to the fly-wheel shaft. [footnote : the revolutions per minute, of these wheels, as here given, are only approximate, as the design was to have the bucket speed=½ (gh)^{½}.] for driving the pumps, there are two water-wheels, set on the same shaft, one feet and the other feet in diameter, either of which can be used at will, thus permitting different rates of speed; two nozzles are placed on each wheel, so that if necessary the power can at any time be doubled. the smaller wheel has a - / inch nozzle, and runs turns a minute; the larger has - / -inch nozzle, and makes turns a minute. there are two ropes from the wheel-shaft to a counter-shaft, and four ropes to the fly-wheel shaft, on which is the pinion driving the spur-wheel attached to the pitman of the pump-bob. hoisting is done by two wheels placed side by side on the same shaft, the buckets and nozzle of each wheel being placed in opposite directions. both wheels are feet in diameter, with / -inch nozzles, and make at full speed about turns a minute. reversing the movement of the shaft is done by shutting off water from one wheel, and turning water on the other wheel; the two water-gates for these nozzles are quickly opened or closed by hydrostatic pressure, afforded from the water main. in addition to the usual brakes on the winding-reels, a brake is placed on the wheel-shaft, so that it can be stopped in a very short period of time. the shock to the pipe by the almost instantaneous cutting off the water at these hoisting-wheels (nearly one cubic foot per second) has not apparently had any injurious, effect. to lessen this shock, a compensating balance was designed, but which is not now in use. a wheel, of small diameter, is used for the smithy, etc., running at a very high velocity. the wheel driving the stamp-mill is feet in diameter, makes revolutions a minute, and is supplied through a - / inch nozzle. the head of water at this point is a few feet greater than at the other wheels. power is transmitted from the hoisting and mill-wheel shafts by two and four ropes, the same as with the pumping rig. the amount of work done, or of water used, has not been carefully determined; judging from the indicator cards taken from the old steam-engines, the managers of the idaho believe that an efficiency of fully per cent. of the theoretic power of the water is obtained on the main driving-shafts of the machinery. the substitution of water for steam-power has resulted in a large saving of expense. although the hills near by are covered with fine forests, thus making wood cheap, and although a round price is charged for water by the company furnishing it, the cost of the water is considerably less than that of the wood formerly used as fuel. the cost of attendance is altogether in favor of the water-wheels, which hardly require any attention. the cost of the change from steam to water-power was $ , . . * * * * * texas creek pipe and aqueduct. a description of this work will be of interest in showing the general practice followed in california for carrying water across deep mountain gorges. in order to augment its water supply, the north bloomfield gravel mining company desired to conduct water from a stream known as texas creek, in nevada county, california, across the big cañon branch of the south yuba river into the main bloomfield flume or aqueduct, which was located on the side of big cañon creek, at a vertical elevation of feet above the bed of the latter stream. the quantity of water to be carried was about cubic feet a second ( , miner's inches), which could be diverted from texas creek at a point feet vertical above the bloomfield flume. an aqueduct about , feet long, partly of ditch and partly of flume, was needed to bring the water from the catchment dam on the creek to the brow of the gorge. the vertical head for the pipe could therefore be from a maximum of feet down to any lesser head; with a head of feet, the pipe would be , feet long; and with a head of feet, the length would be , feet. assuming a maximum tensile strain upon the iron of , pounds per square inch, with the formula for the greatest head of about d = (. l/h)^{ / }, [or, v = (dh/l)^{ / }, and q = ], and a lower value of the coefficient in the last equation for the lesser heads, it was found, by calculation, that the least cost could be obtained with a head from to feet. the head fixed upon was . feet, with a length of , . feet. a profile of the pipe, with nearly the same horizontal and vertical scales (horizontal scale, showing slope lengths), is given in fig. ; details are given in figs. and . the pipe was of double riveted sheet iron, made in lengths of about feet, and of the following thicknesses: , linear feet, . inch thick. " . " " . " " . " " . " " . " , " . " some of the iron was of the very poorest quality; the pipe was made by contract in san francisco, without the supervision of an inspector, as the contractors were a firm of good reputation; the bad quality of the iron was not detected until too late to have it corrected. since then, the writer has always had such pipes--the mines of which he has been the manager using large quantities--made directly on the ground where they are to be used; the pipe makers, in the latter case, always reject such sheets as are too much below in thickness the standard gauge, and those which show in passing through the rolls the bad quality of iron; tests of each joint by hydrostatic pressure would add too much to the cost. [illustration: fig. .] the maximum tensile strain upon each of the seven thicknesses of iron used was intended to be , pounds per square inch. some of the sheets were below the standard gauge, so that, in reality, the tensile strain is sometimes as high as , pounds. the mean diameter of the pipe was . feet. the entrance into the pen-stock was tapered, so that the coefficient of contraction was about . . for pressures not exceeding say feet, the joints were put together stove-pipe fashion. for greater pressures, the joints were made by an inner sleeve riveted on one end of the joint, with an outer lap-welded band, as shown by fig. ; lead was run into the space between the outer band and the pipe, and then tightly driven up by calking-irons. the pipe was laid under the bed of the big cañon creek, a large stream when in freshet, where the head below the hydraulic grade line was feet. some of the lead joints leaked slightly at first, but this was soon remedied by more careful calking. no man-holes or escape-gates were used. the pipe for the larger part of the year is not filled at its upper end; when such is the case, the water at the inlet carries down the pipe a great quantity of air, for which escapes must be provided to prevent a jarring or throbbing, which would soon destroy the pipe. the escape air-valves used are shown by fig. . they consist simply of a heavy flap valve of cast-iron, with recess for lead filling to give greater weight set on top the pipe, seating on a vulcanized rubber cushion, and swinging on a loose hinge. when the pipe is only partly filled with water, the valves drop down by their own weight, allowing the air to freely escape; when the water rises above the level of a valve, it is tightly closed by the resulting pressure. there are fourteen of these valves, those on the lower end being designed to allow air to freely enter the pipe in case it should burst in the deeper portion, and thus prevent any collapse from atmospheric pressure. the valves have answered the desired purposes most effectually. the pipe was hauled over a road built to the inlet end, and shot down the mountain side by means of a v-shaped trough of wood. for the lower end, the joints were hauled up the cliff side into place by a crab worked by horse-power. on steep inclinations, the pipe was held firmly in place by wire ropes fastened to iron pins in the solid rock, as shown by the sketch. the covering of earth and stone was foot to feet in depth; with steep slopes, the earth was kept from sliding by rough dry walls, or by cedar plank placed crosswise. the pipe was laid in ; the first year it broke twice, owing to the wretched quality of the iron; since then, it has given no trouble, and has required practically no attention. the cost of this work--ditch and flume , feet, and pipe , feet--was $ , . . a comparison of the relative values of n, in the formula v = n (r s)^{½}, for the foregoing ditch, flume, and pipe will be instructive. the ditch has a width on the bottom of feet, on the top of feet, with a depth of feet, and an inclination of feet per mile; its sides are rough, being cut in part through the rock and with sharp curves, although fairly regular; with a flow of about , miner's inches ( . cubic feet per second) the ditch runs about full. therefore: + a = ----- × = . ; [tex: a = \frac{ + }{ } \times = . ;] a r = ------------- = . ; . + + . [tex: r = \frac{a}{ . + + . } = . ;] s = ------ = ----- ; [tex: s = \frac{ }{ } = \frac{ }{ };] q = . , hence q v = --- = . ; a [tex: v = \frac{q}{a} = . ;] and / {½} \ n ( in v = n (r s)^ ) = . \ / [tex: n\ (\text{in}\ v = n (r s)^\frac{ }{ }) = .] the flume is of unplaned boards, rectangular, . wide × . deep, with an inclination of feet per mile. there are sharp curves, although these were made as regular as practicable; the boiling action of the water passing around these curves brought the flow line (q = . ) nearly up to the top of the sides; with a straight flume of the same size, the water would have doubtless stood several inches lower. therefore: a = . × . = . ; a r = -------------------- = . ; . + . + . [tex: r = \frac{a}{ . + . + . } = . ;] s = ------ = ----- ; [tex: s = \frac{ }{ } = \frac{ }{ };] q = . , hence q v = --- = . ; a [tex: v = \frac{q}{a} = . ;] and n = . with the pipe,[ ] . diameter, d r = --- = . ; q = . ; v = . . [tex: r = \frac{d}{ } = . ;\ q = . ;\ v = . .] [footnote : _vide_ pages - , transactions american society of civil engineers for .] allowing for loss of head due to imparting velocity to water, and for contraction, . s= --------; and n = . . [tex: s = \frac{ . }{ . };\ \text{and}\ n = .] we hence have the following values of n, in v = n (r s)^{½}, q being constant: rough ditch, with sharp curves. rectangular flume, with sharp curves. wrought-iron pipe, with easy curves, coated with asphalt, but with rivet-heads forming noteworthy obstructions (m = . , and m = n) * * * * * parachute hydraulic motor. the very singular and simple hydraulic motor which we illustrate herewith is the invention of a russian engineer, mr. jagn. it is scarcely as yet known in western europe, where, however, something will probably be heard of it ere long. its true field would seem to be egypt, india, or any country where canals or rivers are used for irrigation, and where it is desired to draw water from them at particular spots in the simplest and cheapest manner. at present in nearly all such cases water is raised by hand or steam power; nevertheless it must be obvious that the current of the canal itself, slow though it may be, is quite sufficient to raise a small portion of the discharge to the very moderate height generally needed to lift it over the banks into the adjoining fields. why then is it not employed for the purpose? the answer is obvious, when we consider the various hydraulic motors at present in use. of course, motors worked by water pressure must here be excluded; and we are left with scarcely anything but the undershot wheel, the turbine, and the screw pump. all these require expensive buildings and erections to set them to work, present but a very small fraction of their surface to the water at any one time, and must be very large and costly if they are to draw even a very moderate amount of power from such a source. there is no possibility of adjusting them readily to suit variations in the speed of the current or in the quantity of water required, nor of moving them from place to place should this be convenient. [illustration: parachute hydraulic motor.] the motor of mr. jagn is on a totally different principle. its essential features consist, as shown, of an endless rope made of hemp or aloe fiber, which takes a turn or two round a pair of drums mounted on a barge or pontoon, and then passes down the channel to return over a pulley hung from a floating punt, at such a depth that the whole of the rope is immersed in the water. along this rope are suspended at equal intervals a number of parachutes made of sail cloth. the rope passes through the center of each of these, and to it are attached a series of strings, the other ends of which are connected to the outside edge of the parachute. thus they act like the spokes of an umbrella to prevent the parachute from opening too far under the pressure of the current. the parachutes must be placed so far apart that the current may act fairly on each, and the sum of the pressures forms the force which draws the rope through the water. the moment, however, that any parachute has passed round the return pulley, the current acts upon it in the opposite direction. it then shuts up like an umbrella, and assumes a volume so small that its resistance on the return journey is insignificant. after passing round the drum at the upper end, it at once opens afresh of its own accord, and once more becomes part of the moving power of the whole system. the parachutes are formed by first cutting out a complete circle of cloth, and then taking from this a sector equal to one-fifth or one-sixth of the total area. such parachutes are found to keep their form when stretched by the water better than a surface originally spherical, although the latter would be theoretically more correct. the motion of the drum is transmitted by spur, gear, or otherwise as may be required, to give the requisite speed. it will be seen that the advantages of the system are as follows: first, the facility it offers for obtaining a large working area, which may be increased or diminished at will, according to the requirements of the moment, by lengthening or shortening the rope. secondly, the ease with which it is erected and set to work. thirdly, the small part of the river section which it occupies, so as to present no obstacle to navigation. fourthly, the ease with which it can be mounted on a barge of any kind, and carried wherever it may be needed. fifthly, it is not stopped, like all other hydraulic motors, by the appearance of ice--it has, in fact, already been worked under ice in the neva. at the same time, winds and waves have no influence upon it. the principle of the apparatus is not altogether new. in there was tried on the ohio river an arrangement termed the brooks motor. it was composed of two drums, placed horizontally and parallel to each other. round these there passed endless chains at equal spaces apart on the length of the drums, and to these chains were fixed wooden blades or arms of a curved form, and so jointed to the frames that they opened when moving in one direction, and closed down on the chain when moving in the other. in this machine the weight of the chains was a serious obstacle to obtaining any large amount of power. the whole apparatus was mounted on a heavy wooden scaffold, which proved an impediment to the flow of the river. again, the resistance due to the surface of the returning blades and to their stiffness was found to be far from insignificant. in the present system mr. jagn has found, after many experiments, that the best effect was obtained when the parachutes were spaced apart at twice their diameter, and when the rope made an angle of degrees to degrees with the current. it is found that when open and in motion the parachutes never touch the bottom. this was the case with a rope containing parachutes of feet diameter, and working in a depth of only feet. this is easily explained by the fact that the velocity of a current always diminishes as it approaches the bottom. hence the pressure on the lower part of the parachute will be less than that on the upper part; but the former pressure tends to draw the parachute downward, while the latter tends to raise it to the top of the water. thus, the latter being the larger, the parachute will always have a tendency to rise. in fact, it is necessary to sink the return pulley sufficiently deep to make sure that the parachutes will not emerge from the surface. for the same reason no intermediate supports are needed over the driving span; if any are needed it is for the return span, on which the parachutes are closed. of course, if metal were used instead of hemp, the case would be entirely different, and intermediate supports would have to be used for anything but very moderate lengths. in practice, mr. jagn has employed two ropes wound upon the same pair of drums, which are mounted upon a pontoon. the ropes are spread out from each other, as in fig. , making an angle of about degrees. the low specific gravity of the system enables ropes to be employed of as great a length as yards, each of them carrying parachutes of . square feet area. as half of these are in action at the same time, the total working area for the two cables is , square feet. this immense area furnishes a considerable amount of power even in a river of feeble current. comparing this with a floating water wheel of the type sometimes employed, and supposing this to have only square feet of working area, such a wheel must have a length of feet, a diameter of feet, and seventy-two floats, each ½ feet wide. the enormous dimensions thus required for a comparatively small working area point sufficiently clearly to the advantage which remains on the side of the parachute motor. the general arrangement of the system is shown in the engraving. behind the return pulleys, d d, are attached cords, a a, with some parachutes strung upon them. these present their openings to the current and preserve the tension of the connecting ropes. at the further end of each cord is a board, b, which is kept in a vertical plane, but lying at a slight angle to the direction of the current; and this acts to keep the two moving ropes apart from each other. the two return pulleys are, however, connected by a line, e, which can be shortened or lengthened from the pontoon, and in this way the angle of inclination between the two ropes can be varied if required. a grooved pulley presses upon the trailing span at the moment before it reaches the circumference of the drum. it is mounted on a screwed spindle, which is depressed by a nut, and thus makes the wet rope grip the outside of the drum in a thoroughly efficacious manner. the author has made a theoretical investigation of the power which may be developed by the system, and has worked out tables by which, when the velocity of the current and the other elements of the problem are known, the power developed by any given number of parachutes can be at once determined. we do not reproduce this investigation, which takes account of the resistance of the returning parachutes and other circumstances, but will content ourselves with quoting the final equation, which is as follows: t = . s v³. here t is the work done in h.p., s is the total working area in sq. m., and v is the velocity of the current in m. per sec. taking v = , and s = sq. m., which is by no means an impracticable quantity, we have t = . h.p. per sq. m. we may check this result by the equation given, in english measures, by rankine--"applied mechanics," p. --for the pressure of a current upon a solid body immersed in it. this equation, f = . m a v² / g, where m is the weight of a unit of volume of the fluid--say lb.--a is the area exposed, and v the relative velocity of the current. mr. jagn finds that the maximum of efficiency is obtained when the rope moves at one-third the velocity of the stream. if this velocity be feet per second, we shall have v = . and we then get f = lb. per sq. ft. very nearly. now sq. meter = . sq. ft., and a speed of ft. per second (which is that of the rope) is ft. per minute. hence the h.p. realized in the same case as that taken above will be × . × / , = . h.p. the difference between the two values is very large, but rankine, of course, depends entirely on the value of the constant . , which is quite empirical, and is for a flat band instead of a hollow parachute. taking, however, his smaller figure, and an area of square inches, which mr. jagn has actually employed, we get a gross power of = . × = . h.p. hence it will be seen that the amount of power which can be realized by the system is far from being inconsiderable. lastly, we may point out that the durability of the apparatus will be considerable. there is no wear except at the moment when the rope is passing round the drum, and even then there need be no slipping or grinding. the apparatus worked in the neva was in very good condition after running for four months day and night. after five months about one-fifth of the parachutes had to be replaced, but after seven months the hemp rope still showed no signs of wear. we think we have said enough to show that for certain purposes, and especially, as we have, already mentioned, for irrigation purposes, the new motor is well worthy of a careful and extended trial. it may be questioned even whether we have not here the germ of an idea which may hereafter enable us to solve one of the most interesting and important of engineering problems, viz., the utilization of the great store of power provided for us twice daily in the ebb and flow of the tide.--_the engineer._ * * * * * improved shafting lathe. our engraving represents a new departure in shaft turning lathes, and is the result of thirty years' experience in the manufacture of shafting, with many years' study, to perfect a machine of the greatest practical capacity and efficiency. [illustration: improved shafting lathe.] the principal points of difference from a common engine lathe are readily distinguished, among which may be mentioned the absence of centers and tail stock, a traveling head with hollow driving spindle, and a stationary tool rest and water tank. by dispensing with a tail stock a much shorter bed may be used, and the hollow driving spindle enables any length shaft to be turned, with one setting of the tools. the tool rest is so arranged as to allow of perfect lubrication of the tools, keeping the shaft cool, and at the same time holding it perfectly rigid and strong; the operator is not required to travel the length of the bed, but remains near the driving belt, feed gearing, etc. power is communicated to the driving spindle by means of a sliding pinion on a splined rod inside the bed, the driving belt and gears being at the end. the driving head, after having traveled the length of the bed and turned a shaft, is returned by a quick feed, and stops automatically, allowing nearly time enough for the operator to grind tools and be ready with another shaft, thus economizing the time completely. wood, jennison & co., worcester, mass., are the makers, and they say that with a good quality of iron they have turned three hundred feet of two inch iron in ten hours. * * * * * power straightening machine. the machine is provided with a pair of rolls at each end of the bed, which are adjustable for different lengths of shaft, and are made to revolve by power applied through suitable gearing and a splined rod inside the bed; the bar of iron being placed on the periphery of the rolls receives a rotary motion by friction, and shows the crooked places in the same way and with the same ease as though rotating on centers in the usual manner; vertically adjustable blocks are arranged in the base of the press to support the iron; power is applied by means of gearing to a splined rod at the back of the machine, on which is a sliding clutch connecting, at the will of the operator, with an eccentric; the eccentric conveys motion and power through a link to the elbow joint at the front of the press, which forces a plunger down against the iron. [illustration: power straightening machine.] sufficient adjustment is provided for different sizes of iron by turning a nut at the top of the press. any point in the length of the bar can be reached by moving the press on the bed. any length of iron can be straightened, and the most laborious and disagreeable work in the process of making shafting is rendered easy and rapid. made by wood, jennison & co., worcester, mass. * * * * * hydraulic mining in california. by george o'brien. our knowledge of the primitive operations of the aboriginal inhabitants of the globe in pursuit of gold is barely traditional, as we are only aware that from very early times the precious metal was collected and highly prized by them, and that they chiefly extracted the visible gold, which existed in prodigious quantities on or closely beneath the surface of the earth, and of its being particularly abundant in asia and africa. but we can draw more positive conclusions as we survey remains of the rude but effective contrivances used by them in later, but still remote, periods, with full evidence as to the extent of their operations, in the numerous perpendicular shafts located at short distances from each other, over large areas of auriferous gravel in india, as well as from precisely similar memorials of ancient workings which remain also further demonstrations, in the abandoned "hill diggings," and shifted beds, and beds of rivers, in peru south america, flowing between the sea and coast ranges of the andes, descending in a northeasterly direction to the river amazon, and that their much coveted and enormous productions were the accumulated riches of the incas, transferred as spoils of war to their spanish conquerors in the sixteenth century. and for similar explorations in the same class of depositions we have the experiences of our own times, and which explain by comparison all the previous operations alluded to. thus in the year , after the cession of the northern portion of mexico to the united states of north america, the rich mineral district of california was at once invaded by hardy and intelligent bands of mining adventurers from all parts of the world, who, with little other means at their disposal but pick, shovel, and pan, soon fell on the productive bars of rivers and rich ravines where the gold was trapped, derived from its original birthplaces, where it had been sparsely disseminated, to be dispersed by the subsequent disintegrations and denudations of the mountains themselves, and deposited in a disengaged form for the first comer; and so perfect were sometimes these concentrations, in certain localities where water once streamed, that, divested of its earthy matrix, the cleansed pure metal was found deposited, detained by its superior specific gravity, on the bare rock, and only hidden from vision by a slight covering of vegetable mould. in this manner, as an example of such concentration, a "pot" or "find" (in mining parlance) to the value of £ , was collected in a space of square yards, or within the limits of a particular "mining claim," at the foot of mokulumne hill, in a southern county of california, soon after the territorial transfer from mexico. and in search of such locations we must account for the numberless shafts which still exist both in india and peru, and sometimes sunk within a few feet of each other, passing through the alluvium to a depth of feet to the bed rock. these mining adventurers soon extended their explorations over the other recently acquired territories, and built virginia city, the capital of montana, with the gold derived from the alluvium of a river channel which they excavated; and its inhabitants were the founders of an institution called the vigilance committee, with "lynch law," and by it ruled supremely for many years. but their surface diggings, by the manual operations alone of multitudes, were soon exhausted in every direction, and then their energies and powers of invention were dedicated to discover and explore deeper and more permanent depositions, along the western slopes of the sierra nevada, the andes of the western territories, and which originally were without doubt several miles higher than they are at the present time--probably , feet above the sea-level--and of which, or whatever superior elevation they formerly had, the greater portion of it has already been removed, by the continuous natural action of centuries, to form there, as elsewhere, the plains and prairies of the earth, burying and diverting by the mutation the ancient river system, whose sources of supply were consequently extinguished by the removal of these altitudes. these denudations and subsequent depositions have been caused by alternations of temperature and combined action of air, water, and time since the creation of the world; and powerful demonstrations of these transformations instruct us in all directions, if we care to observe them. thus in "little cottonwood" ravine, in the wahsatch range of mountains in utah territory, lie isolated in the center of the valley huge masses of metamorphic granite, some blocks of which weigh individually thousands of tons, and were dislodged from the hills--which on either side are of limestone formation--with no visible granite in them, having been undermined by the removal of their pulverized basis by denudation, and which is the material now forming the tablelands, the foundation, of salt lake city. the blocks of granite, having alone resisted the atmospheric changes, were precipitated into the valley beneath, and the mormons are now constructing their cathedral church from these granitic remains. the melting of the snow which formerly capped all these ranges of mountains furnished the water that once flowed in the extinguished channels of ancient rivers, and whose now diverted waters were also the powerful agent to assist in causing these marvelous alternations; and by the means of hydraulic mining we can advance our feeble knowledge on the subject. these mighty changes have gradually been accomplished, and the accumulated denudations of the mineral zones have defended themselves by strata of crystallized silicates of quartz of various thicknesses, and thus in places beneath such system of defense, or by their own concretion, have preserved in many localities a thickness of from to feet of conglomerate, but without this necessary cementation its further removal is very certain when again attacked by water. an example of this continuous process is very observable in "death valley," lower california, where a width of about miles has been filled up from the hills to the gulf of same name, invading and occupying its former bed; and this activity is still proceeding, and a temporary formation of tableland above it is in course of removal, although already overgrown with forest trees, which are toppling over the side which is being attacked. but eternal snow now only covers a small portion of these sierras, and a period of comparative repose may be expected, as the distribution has already been far advanced by the excessive reduction of the mountains. the deep and extensive depositions which i now attempt to describe attracted the early attention of the mining adventurers, and were called "hill diggings," but not being properly understood were therefore not immediately operated upon, and remained in abeyance, while the lower, richer, and more manifest alluvials endured. they were designated "blue gravel," the color being due to the action of sulphuret of iron and other salts, the cementing auxiliaries requisite to form the hard conglomerate, and on exposure to the atmosphere changes color to yellow and violet, losing also its firmness by oxidation. the "great blue lead" is another important mining term and designates the alluvium found reposing in a well-defined channel on the bed rock, being the well-worn path of an ancient river; and it is obvious that the material in these channels should be richer than the general mass beyond their limits. "rim rock" is the boundary line of the banks of the old channel, and, like the bottom, is well worn and corrugated by the running water into cavities and "pot holes," where the force of the stream eddied. the width of these channels varies from to feet, and the cement near the rim and bottom is always richer than elsewhere. the wider and deeper channels generally course from n. to n.w. the richest and most explored belt of gold-bearing alluvium in california lies between the south and middle yuba rivers, commencing near eureka, in nevada county, and extends downwards to smartsville and timbuctoo, in yuba county, a distance of miles; and from among snowy mountains the country falls gradually from where the ravines or canons are cut by the actual rivers, which are , feet beneath the auriferous gravel and region near smartsville, and , feet above the yuba river, where snow is unknown, and near its terminus the ancient river bed courses more westerly than it does above it, and crosses yuba below timbuctoo, where the auriferous depositions disappear. the whole distance of miles has been ransacked by the earlier adventurers, and around the village of timbuctoo was a center famed for its wonderful yield of gold, obtained chiefly in the ravines, in holes, and depressions in the bed rock. these hollows detained the concentrations of the denudated alluvium from the altitudes, and were generally closely beneath the surface, and by such guidance and means of discovery the miners traced the gold up the ravines to their sources in the lofty mounds and deposits, or hills of cemented conglomerate, near eureka in nevada county; and by constructing canals from a higher level began the new system of "hydraulic mining" and washing, and gradually extended their operations over the area of the metallic zone mentioned, of miles long by wide, using the yuba river below timbuctoo to receive and discharge the tailings, or refuse from their operations. the result in gold was considerable, but the system is from its violent nature difficult to control, by presuming to handle and remove such huge depositions in order to collect the richest material. the idea was bold, being an anticipation of nature's operations; but the equitable disposal of the "tailings" in a cultivated country is impossible, as the silt runs down the rivers, creating banks and bars in their channels, obstructing navigation and agricultural arrangements. _general description of hydraulic mining._ the first work to be accomplished, after calculating that the amount or value of the material to be operated upon is sufficient to guarantee the cost of the undertaking in general, is the construction of a canal or canals, to convey the requisite volume of water from the fountain-head, and of sufficient elevation to command the ground to be worked upon, having also in view the levels of the necessary tunnels and shafts as outlets for the discharge of the gravel through them, these being engineering operations requiring much skill and labor to avoid useless after-cost. aqueducts of considerable elevation have to be constructed across deep valleys, and the speculation is at all times problematical, as the ground cannot be properly tested until the water arrives upon it, and disputes may arise between the shareholders of the canal and the mining company, ending frequently in the one devouring the other, unless the two interests be quickly amalgamated. the starting point should be the lowest level, or "bed rock," on the white cement in the ancient channel, which is probably the original silt collected in it, and is harder than the conglomerate above it, which is more easily removed. the courses of these beds can be easily traced by landmarks and undulations, and occasional exposures of the bed rock at low levels; also trial shafts are sunk in various places in search of it, to a depth of feet, passing through blue gravel. the grades of these beds are not steep, being from to feet per mile as of an ordinary river, and the calculated thickness of the alluvial conglomerate is about feet in many places across the ridge between the south and middle yuba river across the columbia. the power of the water for the operation is dependent on a given volume deposited in a reservoir, and at sufficient elevation above the points of discharge, as on this depends effectivity to tear down the gravel. it is delivered to the miner by huge pipes made of wrought iron, and laid down to follow the curvatures of the surface of the ground; and the pipe i now treat of, belonging to the excelsior water company, has a diameter of inches on a length of , feet, and inches on the rest of its length of , feet, being , feet in all; and this large pipe forms an inverted siphon across a valley, following on the gravel, to the top of the hill into the reservoir. these pipes offer advantages over wooden aqueducts for spanning chasms, and also to avoid coursing the sides of valleys; being also cheaper to construct in general, and less liable to accidents from fire and storms, and have the convenience for conveying the water from point to point, as the work of excavation advances, necessitating the removal of portions of the aqueduct forward. the watershed, or reservoir, of the excelsior company embraces the valley of the south yuba and its affluents, and the entire cost of its eight amalgamated canals was , dollars. the rainfall during three years in the mountains averaged inches annually, while the medium in the same period did not exceed inches in the plains beneath. the height of the reservoir above the tailing, or yuba river, is feet: and the height of the head above the floor, or outlet sluice-tunnel, of the blue gravel mining company was feet. the exact quantity of water required to wash every class of gravel is difficult to estimate, but no quantity or pressure would be excessive if properly arranged. the measurement of water is effected by miner's inches, by allowing it to flow from the reservoir of the seller to the purchaser through a box or feet square, with divisions to obtain a quiet head, with a slide or opening capable of adjustment to any required measure; thus an opening of inches by inches, with a quiet head of inches above the middle of the orifice, would give inches, or about , cubic feet of water, flowing during ten hours per day, being an amount necessary for a first-class operation. the capability of the excelsior canal in rainy seasons reached to a delivery in twenty-four hours, to the various mining companies, of , , cubic feet of water, or , miner's inches, and the value of the water paid for by the blue gravel company in forty-three months ending november , , was , dollars, being at the rate of cents of a dollar per miner's inch; and the proportion of water used to wash down , cubic yards of gravel was , , cubic yards, or ¼ cubic yards of water to cubic yard of gravel; and when at work the quantity of gravel daily moved was , cubic yards, and the estimated cost to move one cubic yard of gravel was and / cents of a dollar. but in the face of contingencies the blue gravel company moved , , cubic yards of gravel in four years, or at the rate of , cubic yards per annum, and the cost of washing each cubic yard stands thus: cents. cost of water, at cents per miner's inch . cost of labor, gunpowder, sluices, and superintendence . ----- . or ¾ cents of a dollar per cubic yard. thus the gravel should contain gold to the value of cents of a dollar per cubic yard to cover cost, and the value of the gravel referred to ranged from to cents per cubic yard; and the cost of work done in shafts and tunnels, in the said blue gravel company's mining claim, reached , dollars. but with the cost of the necessary canals paid for by the excelsior water company apart, the total cost amounted to about , , dollars, and we must note that the latter company sold water to other mining companies. the gross yield in gold of the blue gravel company in four years was , dollars, and in the year the returns from the blue gravel company paid all the costs of the developments; but in assessments were paid by the owners to meet the deficiency arising from the cost of sinking two new shafts, and driving fresh tunnels on the lowest levels, which evidently contain on the bed rock the richest concentrations. in smaller mining adventures of this description, involving less capital, large profits have been made in the gold-bearing zone treated of, by also not having invested in costly canals, which would not have repaid the latter investment; and thus it is evident that the water companies are dependent blindly on the prosperity of the miners. i will now more minutely describe the actual mining operations. the mining ground being selected, a tunnel is projected from the nearest and most convenient ravine, so that the starting-point on the bed rock toward the face of the ravine shall approach the center of the material to be removed at a gradient of in to in . the dimensions of such tunnels are usually feet in width by in height, and continuing in contact with the hard river-bed, for the greater ease of excavation, collection of gold, and conservation of quicksilver amalgam. these tunnels vary in length from a few hundred feet to a mile, and some of the longer ones occupying from one to seven years in execution, at a cost of from to dollars per foot of frontage. the tunnel of the blue gravel company, with length of , feet, cost in labor alone , dollars, but it could now be driven for , dollars, as skilled labor is cheaper now than then. the grade in this tunnel is about per cent., and the end of the tunnel is designed to be feet of elevation, and reaching to a point beneath the surface of the gravel which is being operated upon, and where a shaft or incline is sunk to or through the bed rock or gravel, until it intersects the tunnel. the object of this laborious operation is obvious, as the long tunnel becomes a sluiceway, and through the whole length of which sluice boxes are laid, for the double motive of carrying off the material and saving the gold, and for this purpose a trough of strong planks is placed in the tunnel, ½ feet wide, and with sides high enough to contain the stream. the pavement of the trough is generally laid of blocks of wood inches in thickness, cut across the grain, and placed on their ends, to the width of the sluiceway. the wooden blocks are usually alternated with sections of stone pavement, the stones being set endwise, and in the interstices between the stones and wooden blocks quicksilver is distributed, and as much as tons of this metal is required to charge a long sluice. the water in the canal is brought by aqueducts, or other means, to the head of the mining ground, having an elevation of to ft. above the lowest level of the mining ground, and is finally conveyed to it by iron pipes, sometimes sustained on a strong incline of timber. these pipes are of sheet iron, of adequate strength, riveted at the joints, and measure from to inches in diameter, and communicate at the bottom with a strong prismatic box of cast-iron, on the top and sides of which are openings for the adaptation of flexible tubes, made of very strong fabric of canvas, strengthened by cording, and terminating in nozzles of metal of ½ to inches in diameter. from these nozzles the streams of water are directed against the face of the gravel to be washed, exercising incredible effectivity. the volume of water employed varies of course with the work to be done; but it is not uncommon to see four such streams acting simultaneously on the same bank, each conveying from to inches of water per hour-- , miner's inches being equal to , cubic feet of water per hour, constantly exerting its force under a pressure of to pounds to the square inch, varying with the height of the column. under the continuous action of this enormous force, aided by the softening power of the water, large sections of the gravelly mass are dislodged, and fall with great violence, the _debris_ speedily disintegrating and disappearing under the resistless force of the water, and is hurried forward in the sluices to the mouth of the shaft, down which it is precipitated with the whole volume of turbid water. bowlders of to lb. in weight are dislodged and shot forward by the impetuous stream, accompanied by masses of the harder cement which meet in the fall, and by the concussion from the great bowlders the crushing and pulverizing agency required is found to disintegrate it. the heavy banks, of feet and upward, are usually worked in two benches, the upper never being so rich as the lower, and also less firm, and therefore worked away with greater rapidity. the lower section is much the more compact, as this stratum on the bed rock being strongly cemented resists great pressure, and even sometimes the full force of the streams of water, until it has been loosened by gunpowder or other explosives. for this purpose adits are driven in on its foundation-point of from to feet and more from the face of the bank, and drifts are extended at right angles therefrom to a short distance on each side of the adit, and in these drifts a large quantity of gunpowder is placed (from to tons), and fired at one blast, having been previously built in with masonry. and in this manner the compact conglomerate is broken up, and then the water easily completes its work. sometimes in the soft, upper strata the systems of tunnel is extended, as in a coal-mine, by cross alleys, leaving blocks which are afterward washed away, and then the whole mass settles, and is disintegrated under the influence of water. the wooden sluices in the tunnels already described are often made double for the convenience of "cleaning up" one of them, while the other remains in action. the process of cleaning up is performed according to the quantity and richness of the material worked upon, at intervals of twenty to forty days, and consists in removing the pavement and blocks from the bed of the sluice, and then gathering all the amalgam of gold and rich dirt collected, and replacing the locks in the same way as at first. advantage is taken on this occasion to reverse the position of the blocks and stones when they are worn irregularly, or substitute new ones for those which are worn through. the mechanical action of the washing process on the blocks is of course very rapid and severe, requiring complete renewal of them once in eight to ten weeks. some miners prefer a pavement of egg-shaped stones set like a cobble-stone flooring, the gold being deposited in the interstices. most of the sluiceways are, however, paved with rectangular wooden blocks, with or without stones as described. standing at the mouth of one of the long tunnels in full action, any person unaccustomed to the process is struck with astonishment, amounting almost to terror, as the muddy mass sweeps onward, bearing in its course the great rolling bowlders, which add their din to the roar of the water, the whole being precipitated down a series of falls, at each of which it is caught up again by new sluices of timber, lined like the first, and so onward and downward many hundreds of feet until the level of the river is reached, at a distance of about a half mile or more from the mouth of the first tunnel. at each of these new falls of to feet the process of comminution begun in the first shaft is carried on, and a fresh portion of gold obtained. rude as this plan of saving gold appears to be, more gold is procured by it than by any other method of washing yet devised for this process of work, and the economical advantages obtained by it cannot be surpassed, as it would be impossible to handle such vast quantities of material in any other way, and we can compare the cost of washing and handling a cubic yard of auriferous gravel by it as follows: dollars. by manual labor with the pan . " " with rocker . " " with the long tom . by the hydraulic process . but this process, even if effective or profitable as a mining operation, may be prejudicial to the interests of the general public, if conducted on a large scale, as the vast quantity of material which it so suddenly removes is merely shifted into the shallows beneath, to be redistributed by every freshet to points lower and lower down until it reaches the sea-coast, creating bars at the mouths of rivers in its course, and changing the hydrography of harbors--as it has done with the bay of san francisco by its silt. the hills behind, torn up and washed by the gold miner, are abandoned as desolate and irredeemable; and the costly canals, constructed with peculiar conveniences for mining purposes, eventually fall into disuse from being too expensive to maintain or alter for general agricultural uses.--_journal of science._ * * * * * the treatment of cholera. from the host of remedies and suggestions that are now deluging the european medical press, we select the following from dr. henry a. rawlins, in the _london med. times_, july . : the man suffering from cholera has been suddenly deprived by diarrhoea of an enormous quantity of the fluid part of his blood. this loss is one of simple transudation, increasing as the powers of life decrease. this _sudden_ loss produces intense prostration, and renders the heart powerless to perfect the circulation. the body, thus deprived of oxygen, speedily runs into decomposition, even before life is extinct. have we any agent by which we can collect and press forward these scattered and lethargic drops of blood to the heart, and enable it to renew the circulation, and with it the blessings of oxygen to the body? my reply is emphatically--yes! flannel bandages from the toes to the trunk, around the abdomen, and from the fingers to the body, will effect this object perfectly. remark that the effect is gradual, increasing with every turn of the roller, but would be in full force in about twenty minutes. by thus exposing the blood in the lungs to the action of oxygen in its diluted form, as it is in the air, instead of pure oxygen, the reaction would neither be too rapid nor too dangerous. in confirmation of my views, i have this day learned that it is the custom in india to wear a double roll of flannel around the abdomen, as a preventive to cholera. the other advantages resulting from the use of the flannel bandages are: . that they prevent the escape of heat from the body of the poor creature who is already in a state of refrigeration. . by their firmly and equally grasping both flexor and extensor muscles alike, they are steadied, and rendered much less likely to be affected with spasmodic action or cramp. . by their steady _elastic_ pressure and support of about pounds, they persistently keep up and sustain the circulation of the blood, which they had previously restored. . that the oxygen thus well secured to the blood will, i believe, prove quite sufficient to neutralize the original poison, and also destroy its effects. . that this much can at least be claimed for their use--that they remove from nature a stumbling-block, which prevented her from exercising her marvelous recuperative powers. diluted sulphuric acid is the best medicine to arrest the flux from the bowels, acting also as a tonic. it should be given in five-minim doses about every half hour, with rice gruel. by adopting this plan, the natural process is brought about, that of the starch being converted into grape sugar. plenty of white of egg, well whipped up, so as to nourish the body and convey oxygen into the stomach, which it will appropriate, should be given. opium, in small quantities, and other stimulants, should be given according to the necessities of the case. may it not be well, through the medium of wet sponge over the thorax, to apply a continuous but gentle current of galvanism, so as to stimulate the heart's action, keep alive the respiratory movements, and thereby assist in the maintenance of the functions of the body? * * * * * temperature, moisture, and pressure in their relations to health. at the recent meteorological conference held at the health exhibition, dr. j.w. tripe read a paper of much interest on some relations of meteorological phenomena to health. in ages long past these relations excited much attention, but the knowledge concerning them was of the vaguest kind; and indeed, even now, no very great advance has been made, because it is only quite recently that we have been able to compare a fairly accurate record of deaths with observations taken at a number of reliable meteorological stations. the more useful and searching comparison between cases of sickness, instead of deaths, and meteorological phenomena has yet to be accomplished on a large scale in this country, and especially as regards zymotic diseases. in belgium there is a society of medical practitioners, embracing nearly the whole country, that publishes a monthly record of cases of sickness, of deaths, and of meteorological observations; but the only attempt on a large scale in this country, which was started by the society of medical officers of health for the whole of london, failed partly from want of funds, and partly from irregularity in the returns. my remarks, which must necessarily be very brief, will refer to the relations between ( ) meteorological phenomena and the bodily functions of man, and ( ) between varying meteorological conditions and death-rates from certain diseases. as regards the first, i will commence with a few brief remarks on the effects of varying barometric pressures. a great deal too much attention is paid to the barometer if we regard it as indicating only, as it really does, variations in the weight of the column of air pressing upon our bodies, because, except at considerable elevations, where the barometer is always much lower than at sea level, these variations produce but little effect on health. at considerable elevations the diminished pressure frequently causes a great feeling of malaise, giddiness, loss of strength, palpitation, and even nausea; and at greater heights, as was noticed by mr. glaisher in a very lofty balloon ascent, loss of sight, feeling, and consciousness. these were caused by a want of a sufficient supply of oxygen to remove effete matters from the system, and to carry on the organic functions necessary for the maintenance of life. on elevated mountain plateaus, or even in high residences among the alps, an increased rapidity in the number of respirations and of the pulse, as well as increased evaporation from the lungs and skin, occur. for some years past, many persons suffering from consumption, gout, rheumatism, and anæmic affections have gone to mountain stations, chiefly in switzerland, for relief, and many have derived much benefit from the change. it must not, however, be supposed that diminished atmospheric pressure was the chief cause of the improvement in health, as its concomitants, viz., a diminution in the quantity of oxygen and moisture contained in each cubic foot of air, probably the low temperature, with a total change in the daily habits of life, have assisted in the beneficial results. the diminution in the quantity of air, and consequently of oxygen, taken in at each breath is to a certain extent counterbalanced by an increased frequency and depth of the respirations, and a greater capacity of the chest. in this country, alterations in the barometric pressure are chiefly valuable as indicating an approaching change in the wind, and as well as of the amount of moisture in the air; hence the instrument is often called "the weather glass." a sudden diminution in the atmospheric pressure is likely to be attended with an escape of ground air from the soil, and therefore to cause injury to health, especially among the occupants of basement rooms, unless the whole interior of the building be covered with concrete. _temperature._--experience has shown that man can bear greater variations of temperature than any other animal, as in the arctic regions a temperature of - degrees fahrenheit, or more than degrees below freezing point, can be safely borne; that he can not only live but work, and remain in good health, in these regions provided that he be supplied with suitable clothing and plenty of proper food. on the other hand, man has existed and taken exercise in the interior of australia when the thermometer showed a temperature of degrees fahrenheit, or nearly degrees above freezing point, so that he can live and be in fairly good health within a range of nearly degrees fahrenheit. the effects of a high temperature vary very much according to the amount of moisture in the air, as when the air is nearly saturated in hot climates, or even in summer in our own, more or less languor and malaise are felt, with great indisposition to bodily labor. with a dry air these are not so noticeable. the cause is evident; in the former case but little evaporation occurs from the skin, and the normal amount of moisture is not given off from the lungs, so that the body is not cooled down to such an extent as by dry air. sunstroke is probably the result, not only of the direct action of the sun's rays, but partly from diminished cooling of the blood by want of evaporation from the lungs and skin. the effects of temperature on man do not depend so much on the mean for the day, month, or year, as on the extremes, as, when the days are hot and the nights comparatively cool, the energy of the system becomes partially restored, so that a residence near the sea, or in the vicinity of high mountains, in hot climates is, other things being equal, less enervating than in the plains, as the night air is generally cooler. it is commonly believed that hot climates are _necessarily_ injurious to europeans, by causing frequent liver derangements and diseases, dysentery, cholera, and fevers. this, however, is, to a certain extent, a mistake, as the recent medical statistical returns of our army in india show that in the new barracks, with more careful supervision as regards diet and clothing, the sickness and death-rates are much reduced. planters and others, who ride about a good deal, as a rule keep in fairly good health; but the children of europeans certainly degenerate, and after two or three generations die out, unless they intermarry with natives, and make frequent visits to colder climates. this fact shows that hot climates, probably by interfering with the due performance of the various processes concerned in the formation and destruction of the bodily tissues, eventually sap the foundations of life among europeans; but how far this result has been caused by bad habits as regards food, exercise, and self-indulgence, i cannot say. rapid changes of temperature in this country are often very injurious to the young and old, causing diarrhoea and derangements of the liver when great heat occurs, and inflammatory diseases of the lungs, colds, etc., when the air becomes suddenly colder, even in summer. the _direct_ influence of rain on man is not very marked in this country, except by giving moisture to the air by evaporation from the ground and from vegetable life, and by altering the level of ground water. this is a subject almost overlooked by the public, and it is therefore as well that it should be known that when ground water has a level persistently less than five feet from the surface of the soil, the locality is usually unhealthy, and should not, if possible, be selected for a residence. fluctuations in the level of ground water, especially if great and sudden, generally cause ill-health among the residents. thus, dr. buchanan in his reports to the privy council in - , showed that consumption (using the word in its most extended sense) is more prevalent in damp than on dry soils, and numerous reports of medical officers of health, and others, which have been published since then, show that an effective drainage of the land, and consequent carrying away of the ground water, has been followed by a diminution of these diseases. varying amounts of moisture in the air materially affect the health and comfort of man. in this country, however, it is not only the absolute but the relative proportions of aerial moisture which materially influence mankind. the quantity of aqueous vapor that a cubic foot of air can hold in suspension, when it is saturated, varies very much with the temperature. thus at degrees fahr. it will hold . grains of water; at degrees, . grains; at degrees, . grains; at degrees, . grains; and at degrees as much as . grains. if saturation be represented by , more rapid evaporation from the skin will take place at degrees, and per cent. of saturation, than at degrees when saturated, although the absolute quantity of moisture in the air is greater at the first named temperature than at the latter. as regards the lungs, however, the case is different, as the air breathed out is, if the respirations be regular and fairly deep, completely saturated with moisture at the temperature of the body. in cold climates the amount of moisture and of the effete matters given off from the lungs in the expired air is much greater than in hot climates, and the body is also cooled by the evaporation of water in the form of aqueous vapor. moist air is a better conductor of heat than dry air, which accounts for much of the discomfort felt in winter when a thaw takes place as compared with the feeling of elasticity when the air is dry. in cold weather, therefore, moist air cools down the skin and lungs more rapidly than dry air, and colds consequently result. london fogs are injurious, not only on account of the various vapors given off by the combustion of coal, but in consequence of the air being in winter generally saturated with moisture at a low temperature. the injuriousness of fogs and low temperatures will be presently dwelt upon at greater length. variations in the pressure and temperature of the atmosphere exert a considerable influence on the circulation of air contained in the soil, which is called ground air. as all the interstices of the ground are filled with air or water, the more porous the soil, the greater is the bulk of air. the quantity of air contained in soil varies very much according to the material of which the soil is composed, as it is evident that in a gravelly or sandy soil it must be greater than when the ground consists of loam or clay. the estimates vary from to per cent., but the latter is probably too high. if, therefore, a cesspool leak into the ground, the offensive effluvia, if in large quantities, will escape into the soil, and are given off at the surface of the ground, or are drawn into a house by the fire; but, if small, they are rendered innocuous by oxidation. the distance to which injurious gases and suspended or dissolved organic matters may travel through a porous soil is sometimes considerable, as i have known it pass for feet along a disused drain, and above feet through loose soil. winds exercise a great effect on health both directly and indirectly. directly, by promoting evaporation from the skin, and abstracting heat from the body in proportion to their dryness and rapidity of motion. their indirect action is more important, as the temperature and pressure of the air depend to a great extent on their direction. thus winds from the north in this country are usually concomitant with a high barometer and dry weather; in summer with a pleasant feeling, but in winter with much cold. southwest winds are the most frequent here of any, as about per cent. of the winds come from this quarter against ½ from the west, ½ from the east, and the same from the northeast; ½ from the south, from the north, and a smaller number from the other quarters. southwest winds are also those which are most frequently accompanied by rain, as about per cent. of the rainy days are coincident with southwest winds. another set of observations give precisely the same order, but a considerable difference in their prevalence, viz., southwest per cent., west ½, and northeast ½ per cent. easterly winds are the most unpleasant, as well as the most injurious to man of all that occur in this country. i now propose discussing very briefly the known relations between meteorological phenomena and disease. i say the known relations, because it is evident that there are many unknown relations of which at present we have had the merest glimpse. for instance, small-pox, while of an ordinary type, and producing only a comparatively small proportion of deaths to those attacked, will sometimes suddenly assume an epidemic form, and spread with great rapidity at a time of year and under the meteorological conditions when it usually declines in frequency. there are, however, in this country known relations between the temperature and, i may say, almost all diseases. as far back as i began a series of elaborate investigations on the mortality from scarlet fever at different periods of the year, and the relations between this disease and the heat, moisture, and electricity of the air. i then showed that a mean monthly temperature below . ° f. was adverse to the spread of this disease, that the greatest relative decrease took place when the mean temperature was below °, and that the greatest number of deaths occurred in the months having a mean temperature of between ° and ° f. diseases of the lungs, excluding consumption, are fatal in proportion to the lowness of the temperature and the presence of excess of moisture and fog. thus, in january, , the mean weekly temperature fell from . ° f. in the second week to . ° in the third, with fog and mist. the number of deaths registered in london during the third week, which may be taken as corresponding with the meteorological conditions of the second week, was , , and in the next week , . unusual cold, with frequent fogs and little sunshine, continued for four weeks, the weekly number of deaths rising from , to , , , , , , and , . the deaths from acute diseases of the lungs in these weeks were respectively , , , , and , showing that a large proportion of the excessive mortality was caused by these diseases. at the end of november and in december of the same year there was a rapid fall of temperature, when the number of deaths from acute diseases of the lungs rose from to , , , , , and in the respective weeks. from november to december the sun was seen only on two days for ½ hours, and from december to the th also on two other days for less than hours, making the total amount of sunshine . hours only in days. in january and february the excess of weekly mortality from all diseases reached the large number of deaths; in december it was less, the fogs not having been so dense, but the excess equaled deaths per week. the relations between a high summer temperature and excessive mortality from diarrhoea have long been well known, but the immediate cause of the disease as an epidemic is not known. summer diarrhoea prevails to a greater extent in certain localities, notably in leicester (and has done so for years); and the cause has been carefully sought for, but has not been found out. recent researches, however, point to a kind of bacillus as the immediate cause, as it has been found in the air of water-closets, in the traps under the pans, and in the discharges from infants and young children. in order to indicate more readily how intimately the mortality from diarrhoea depends on temperature, i now lay before you a table showing the mean temperature for ten weeks in summer, of seven cold and hot summers, the temperature of thames water, and the death-rates of infants under one year per million population of london: _london.--deaths under year, in july, august, and part of september, from diarrhoea per , , population living at all ages, arranged in the order of mortality._ age - year. mean temperature deaths from diarrhoea years. temperature, of thames per , , weeks. water. population living at all ages. . ° . ° . . . . . . . . . . . . as may be seen, the deaths of infants under year of age from diarrhoea per , , population was only ; while the mean summer temperature was only . ° f. against in , when the mean temperature was . °. in , when the mean temperature was . °, the deaths from diarrhoea rose to per million, but a few days were unusually hot. in the mean temperature of the air was . °, of the thames water . °, and the mortality of infants from diarrhoea per million population. in , when the mean temperature of the air was . °, the mortality rose to per million; and in the hot summers of and , when the mean air temperatures were . ° and . ° respectively, the death-rates of infants were and per million population. the relations, therefore, between a high summer temperature and the mortality from diarrhoea in infants are very intimate. i have selected the mortality among infants in preference to that at all ages, as the deaths occur more quickly, and because young children suffer in greater proportion than other persons. the proportionate number of deaths at _all ages_ from diarrhoea corresponds pretty closely with those of infants. to prove this, i made calculations for three years, and ascertained that only . per cent. of all the deaths from this disease were registered in the weeks having a temperature of less than °; . per cent. in the weeks having a temperature between ° and °; while in the comparatively few weeks in which the temperature exceeded ° f., as many as . per cent. of the total number of deaths was registered. in the sixteen years, - , for which many years ago i made a special inquiry, only . per cent. of all the deaths from diarrhoea occurred in winter and spring, against . per cent. in summer and autumn. in the twenty years, - , there were seven years in which the summer temperature was in defect when the mortality per , inhabitants of london was ; while in ten summers, during which the temperature was in excess by ° or less, the mortality was per , . the mean temperature was largely in excess, that is to say, more than ° plus in three of these summers, when the mortality reached per , inhabitants. these figures show that great care should be taken in hot weather to prevent diarrhoea, especially among young children; by frequent washing with soap and water to insure cleanliness, and proper action of the skin; by great attention to the food, especially of infants fed from the bottle; free ventilation of living rooms, and especially of bedrooms; and by protection, as far as possible, being afforded from a hot sun, as well as by avoiding excessive exercise. all animal and vegetable matter should be removed from the vicinity of dwelling-houses as quickly as possible (indeed, these should be burnt instead of being put in the dust-bin), the drains should be frequently disinfected and well flushed out, especially when the mean daily temperature of the air is above ° f. time will not admit of more than a mere mention of the relations between meteorological phenomena and the mortality from many other diseases and affections, such as apoplexy from heat, sunstroke, liver diseases, yellow fever, cholera, whooping-cough, measles, etc., especially as the state of our knowledge on the subject is so very limited. a comparison between the mortality from several diseases in this and other countries shows that certain of these do not prevail under closely corresponding conditions. thus the curves of mortality from whooping-cough, typhoid fever, and scarlet fever do not correspond with the curves of temperature in both london and new york, and the same may be said of diarrhoea in india. it is therefore evident that some other cause or causes than a varying temperature must be concerned in the production of an increased death-rate from these diseases. the subject is of great importance, and i do not despair of our obtaining some day a knowledge of the agents through which meteorological phenomena act in the production of increased and decreased death rates from certain diseases, and the means by which, to a certain extent, these injurious effects on man may be presented. * * * * * p. rosenbach has found experimentally that potassium bromide diminishes the sensibility of the cortical substance of the cerebrum to electric excitement, while, the excitability of the underlying white substance remains unaltered. * * * * * consumption spread by chickens. in a village, c., near weimar, where for many years no case of tubercular phthisis had taken place, two years ago several families suddenly discovered one of their members to be suffering from the disease. after a long inquiry, it was discovered by accident that all these families had been buying their spring chickens from one and the same place, viz., from a private hospital in the neighborhood. a medical student brought the livers of two such chickens to prof. johne, in dresden. the student, whose own sister had become affected with consumption, had lived during his vacation at home with his parents, in c., and he had there at dinner observed the peculiar appearance of the liver of the chickens. on examination, both organs were found to be full of tubercular bacilli. a thorough investigation was at once instituted, and it was then that the fact came to light that the chickens eaten by the families, members of which had been affected with tuberculosis, had all been brought from the institution mentioned. on further inquiry at the latter place the following facts were elicited: at about the time when the first case of consumption occurred in the village, an inmate or the hospital, mrs. r., had died of the disease. before her death, mrs. r. used to feed the chickens raised there; she was often seen first to chew the meat before she gave it to the chickens. further, the spittoons were emptied on a place in the yard where the chickens generally came to pick up any stray corn. as none of the chickens ever came in contact with any animals in the neighborhood--the hospital being situated at a considerable distance from the village--as no disease had happened among them until the arrival of mrs. r., when soon after an epidemic seemed to break out among them, and many died, there is no doubt that they contracted the disease from mrs. r., and in return infected those who ate their flesh. the case is very interesting, first, as it proves how such animals may become affected, then how they may spread the disease, and lastly, that some kind of a disposition must exist in the person infected; for here, of many who had eaten of the diseased flesh, only a few contracted the malady. the whole report teaches us how careful we have to be, and how necessary is the appointment of skillful experts by the state to inspect all food offered for sale.--_med. and surg. reporter._ * * * * * new method of reducing fever. for many years eminent medical savants have sought earnestly through the vegetable and mineral worlds for some substance by means of which the high temperature often prevailing in typhoid, malarial, and other fevers might be reduced with rapidity and safety to the patient. a few substances have been found which produce a decline in temperature when administered in enormous and frequently repeated doses; but such administration has often been found to be decidedly detrimental to the patient, producing not infrequently serious injury to the stomach, kidneys, and sometimes the nervous system. so great is the danger of such injurious results, few careful practitioners have cared to adopt the heroic "antipyretic" medication recommended by experimenters, preferring to allow their patients to burn with fever, mitigated only by such simple means as are commonly employed by nurses, than to require them to combat the poisonous influences of a drug in addition to the morbid element of the disease. happily, however, it is not necessary to leave the patient to the unaided efforts of nature. by cool sponging of the surface, persistently and thoroughly applied; by large, cool compresses placed over the abdomen and chest, or even the whole front of the body, and changed as often as warm, or every three to five minutes; by frequently repeated cool packs; by cold water drinking; by ice-packs to the spine; by constant application of ice or frozen compresses to the head; by forcing perspiration by copious hot drinks and a warm blanket pack--by any or all of these means the temperature may be reduced with promptness in nearly every case. however, cases will now and then occur in which the temperature remains dangerously high, notwithstanding the thorough application of the above means. what shall be done? several years ago our attention was called to a series of experiments made by dr. winternitz, professor of hydropathy in the medical university of vienna, for the purpose of determining the influence upon temperature of enemas of water of different temperature in cases of fever. the results claimed by prof. winternitz were so striking that we improved the first opportunity to repeat his experiments, and with such results as have justified the continued use of this means of lowering temperatures in fever, in cases in which the ordinary measures were not efficient. the only objection we have found to the method has been the inconvenience to the patient occasioned by the frequent use of the bed-pan. in a recent case in which we found it necessary to resort to this method, the nurse observed that if the tin can of the fountain syringe used in administering the enema happened to be lowered below the level of the bed on which the patient lay, water which had previously been introduced into the rectum returned readily through the tube into the can. on learning this fact, the attendants were instructed to employ the enema in this way. from one to two pints of water, of ° or ° f. temperature, were allowed to pass into the bowels; and after being retained for five or ten minutes, or until the patient experienced uncomfortable sensations, it was made to pass out through the tube by simply lowering the reservoir to the level of the floor. a new supply of water of a proper temperature being introduced into the reservoir, it was again raised to the proper height, and the operation so continued until six quarts of water had been used. then the patient was allowed to rest half an hour or an hour, according to the height of the fever, and the same process was repeated. careful record was made of the temperature of the patient just before the treatment and immediately after. it was found to be invariably reduced from one to one and a half degrees by each treatment. the temperature, which had been exceedingly obstinate previous to the employment of this method, ranging from ° to °, during the intervals between the treatments would, of course, rise somewhat; but each time it stopped short of the point reached during the previous interval, so that in the course of a few hours the fever was brought down to very nearly a normal temperature. the temperature of the water, when taken after passing through the bowels, was found to have risen each time from ° to °. the great capacity of water for absorbing heat renders it one of the most useful of all substances for lowering the temperature; and it is readily apparent that, by the means described, heat may be abstracted from the body almost _ad libitum_, and the temperature may thus be controlled with a rapidity and a degree of certainty which cannot be approached by any other method. in a still more recent case, in which the same treatment was employed, the temperature of the patient had reached ° f., in spite of the vigorous application of ordinary measures of treatment, such as cold compresses, etc.; but it was, in four or five hours, brought down to nearly ° by the use of the cold enemas. the advantages of this method are: . it may be employed without wetting or moving the patient; very frequently a patient will sleep continuously during the administration of the treatment. . it seldom causes chilliness, which is frequently a disturbing symptom, especially in fevers of a low type, and even, when the temperature is alarmingly high, causing the patient to dread the employment of sponging with cool or tepid water. . it is not necessary to employ cold water, a temperature of ° or even ° being thoroughly efficient. in the majority of cases, however, water of ° or even ° may be employed without danger. the water comes in such immediate contact with surfaces filled with large blood-vessels that a temperature but a few degrees below that of the body is more effective than very much colder water applied to the surface. in cases in which the use of the cool enema is attended by chilliness, this uncomfortable symptom may usually be relieved by the application of a hot bag or fomentations to the spine or to the pit of the stomach. the simple measures of treatment we have described will be found more effective in lowering the temperature than any or all other remedies which have ever been recommended for this purpose.--_good health._ * * * * * the crown diamonds of france. [illustration: fig .--the crown diamonds of france at the exhibition of industrial arts.] according to a recent law of parliament, a large part of the crown jewels of france is destined to be sold. the exhibit that has been made of these riches for the last two months at the national exhibition of the industrial arts, in the state hall of the louvre, has excited a lively interest among the visitors. here are to be seen, heaped up in a large octagonal show-case, incomparable treasures, whose value exceeds quite a number of millions. according to the inventory of , the , precious stones of the crown of france were estimated as worth more than million francs ($ , , ); but since that epoch the stones have increased in number, and money has singularly diminished in value, so that the total at present would be much less. [illustration: fig. .--the regent. (actual size.)] in order to publicly exhibit so valuable treasures it was necessary to take precautions against thieves and fire, and this was done in a very sure and ingenious manner. the collection of crown jewels is distributed over the eight faces of an octagonal truncated cone, which is supported by a framework about three feet in height at the lower part. the stand is exhibited every day, at ten o'clock in the morning and six in the evening, under an elegant octagonal show-case surmounted by a high bronze statue of fortune by barbedienne. the whole is covered with a canopy, as shown in fig. . a force of guardians of the treasury is detailed to watch over the crown jewels, and it is to them that is confided the care of operating in the morning and evening the safety mechanism that we shall describe. the object of this mechanism is to lower into and lift out of the strong-box the entire stand with all its jewels. a winch, shown at a to the right of the engraving, sets in motion a system of gear wheels keyed at an angle, at b and c, upon intermediate shafts that transmit motion to the four vertical threaded rods of the frame, d. all these shaftings are ½ inch in diameter, and the cog-wheels, twenty in number, are about inches in diameter. the well is formed of an octagonal wall of fire-brick, and is inches thick and feet high. in the center of this masonry is embedded very thick iron plate. the bottom of the well is isolated from the flooring of the exhibition hall by a thickness of boiler plate, by a filling of tire bricks, and finally by a second thickness of boiler plate. the well is closed by means of a large plate of iron inches thick, feet in length, and feet in width. the winch which maneuvers this mass is placed at e. it actuates a system of bevel wheels, keyed at f, which transmit motion to two horizontal screws (hidden under the stage) that actuate the plate, h. this latter is provided with two parallel series of five rollers each that revolve over long and strong pieces of wood covered with rails. electric alarms are located near the winches. a fire-engine station is located at within twelve or fifteen feet of the exhibition building. a committee composed of competent jewelers and mineralogists has been appointed to make an appraisement of the diamonds and to indicate such as should be withheld from sale on account of their scientific, artistic, or historic interest. the members of the committee propose to preserve the following objects: . the "regent" (fig. ), by reason of its mineralogical value, the perfection of its cutting, the purity of its water, its incomparable luster, and its great size, it being the largest brilliant as yet known. . the military sword of charles the tenth's coronation, the hilt of which is entirely of brilliants mounted by bapst with wonderful art. . the jewel called the "reliquary," of the th century. to these riches must be added the following interesting objects: the dey of algiers' watch; the elephant of denmark; the decorations, etc., of foreign orders; crowns and diadems of sapphire; rubies; pearls that afford curious specimens of french art at the beginning of our century; one of the mazarins bequeathed by the celebrated cardinal; and lots of colored stones destined for our national museums. the same exhibition alluded to above contains a number of other collections of great interest that it would be unjust to pass over in silence, such as the exhibit of the french diamond mines of the cape, where one may see all the details of this prosperous exploitation by means of photographs and specimens. the art bronzes, the objects of jewelry, of goldsmith's work, and of morocco work, the music boxes, trouve's and aboilard's electric jewelry, and the retrospective art collections especially attracted the attention of the public.--_la nature._ * * * * * a new mode of testing the economy of the expenses of management in life insurance. how to determine the general ratios of the expenses of management of life insurance companies has hitherto been an unsettled question, and i think no serious attempt has been made before my own to study this question exhaustively, and reach a scientific conclusion. believing that, one is contained in the following statement, i respectfully submit it to the criticism of others. it has generally been taken for granted that the measure of economy of life insurance expenses may be expressed by the single ratio of expenses to one feature of the business, such as the premium income, or the total income (premium and interest), or the mean amount of all policies outstanding. but this is not the case. no exhaustive reason has been shown for preferring one of these bases of ratio to another, and, indeed, no reason well supported by argument has been shown for employing either. on the other hand, no better evidence is needed of the importance of establishing a uniform and demonstrably sound basis, than the fact that it is common for companies to refute one another's claims to superior economy, and totally confuse the public, by opposing ratios found in one way by ratios found in another--that one of two companies which appears the most economical according to one test being apparently the least so according to another. the economy of the expense of any transaction, or work, can only be intelligently judged by the value of the _result_. this truth is too well recognized to need illustration, and it only needs to be called to mind, to perceive both the error of ratios of expense based on premium, which is not the result but the _raw material_, so to speak, of insurance transactions; and what, on the contrary, the true basis is. it is thus clear that in insurance the economy of expense must be judged, not by comparison with the premiums paid, but by comparison specifically with the resulting advantages in fact secured by such payments. now these are of two kinds: which may be called the _insurance advantage_ and the _investment advantage_. ( ) each death claim paid is an insurance advantage, though it is so only to the extent of the excess of the amount of the policy which has become a claim over its premium reserve, or value, for the latter being the balance (with interest) of the policy holder's own premium money, could have been left or secured to his representatives without the intervention of the policy and company. it is true that the advantage or benefit of insurance does not consist in adding anything to the wealth of a company, but only consists in drawing from the premiums paid into its treasury by the policy holders generally, to meet each death claim which arises; or can only be called an _advantage of distribution_, or process of collecting aid from the living members, to assist the representatives or dependents of the deceased ones; but it is not the less on this account an advantage worth _same expense_ in securing. ( ) interest realized by the investment of premium while it is in the keeping of a company is an advantage; in every sense so, since it comes wholly from outside sources, and accrues proportionally to all members; it may be called, as above, the investment advantage, and of course justifies some _expense_ to secure it. hence the expenses incurred by any company in a given; time must be divided into two parts, one being the expense incidental to insurance, and the other that incidental to investment, which parts are to be compared respectively with the insurance claims met, and interest receipts of the company for the same time; or what is equivalent in the latter case, the net rate of interest earned after deducting the incidental investment expense may be found. when this process shows that one company has earned a higher rate of interest than another, at the same time that its insurance expenses bear a lower ratio to its insurance claims paid, _there is no escape from the conclusion that during the period under observation it has served its policy-holders more economically_, and the test is therefore scientific. though, if one company shows a higher rate of interest, while the other shows a lower ratio of insurance expense, it will still be necessary, to complete the test, to equate either the rates of interest or the ratios of insurance expense (it does not practically matter which), and note how this affects the relation of the duly corrected ratios on the other score. to be exact, if the average vitality of the members of the two companies differ (other things being equal, it is always cheapest to belong to that company which has the lowest death rate), the ratios of insurance expense to expected, as well as actual, claims of each must be found, and equated. the science of this procedure, or mode of testing expenses, and also its practical simplicity, may be more clearly perceived by reference to its practical application in the following table: _table exhibiting ratio of expense, determined by the new mode, of companies doing business in massachusetts during the year ._ ___________________________________________________________________________________________________________________ | | | | | | | | | | | | | | |expense | | |net rate | | | | | |per $ | | | of | | | | | |of claims| | |interest | | death |estimated |difference |expense |paid. | interest | expense | earned. name of company. |loca-| claims |premiums. | or net | on the |---------| receipts. | on the |-------- |tion.| paid. | reserve |insurance |score of | r | r | | score of | r | r | | | thereon. |furnished. |insurance. | a | a | |investment.| a | a | | | | | | t | n | | | t | n | | | | | | e. | k.| | | e. | k. -------------------+-----+-----------+----------+-----------+-----------+-----+---+-----------+-----------|----|--- berkshire |mass.| $ , | $ , | $ , | $ , | . | | $ , | $ , | . | [ ]john hancock | " | , | , | , | [ ] , | . | | , | , | . | mass. mutual | " | , | , | , | , | . | | , | , | . | n. england mutual | " | , , | , | , | , | . | | , | , | . | state mutual | " | , | , | , | , | . | | , | , | . | Ætna |conn.| , , | , | , | , | . | | , , | , | . | connecticut general| " | , | , | , | , | . | | , | , | . | " mutual | " | , , | , | , , | , | . | | , , | , | . | equitable | n.y.| , , | , | , , | , , | . | | , , | , | . | germania | " | , | , | , | , | . | | , | , | . | home | " | , | , | , | , | . | | , | , | . | homoeopathic | " | , | , | , | , | . | | , | , | . | manhattan | " | , | , | , | , | . | | , | , | . | [ ]metropolitan | " | , | , | , | , , | . | | , | , | . | mutual life | " | , , | , , | , , | , , | . | | , , | , | . | mutual benefit | n.j.| , , | , | , , | , | . | | , , | , | . | national | vt. | , | , | , | , | . | | , | , | . | new york life | n.y.| , , | , | , , | , , | . | | , , | , | . | northwest'n mutual | wis.| , | , | , | , | . | | , , | , | . | penn. mutual |penn.| , | , | , | , | . | | , | , | . | provident life and | | | | | | | | | | | trust | " | , | , | , | , | . | | , | , | . | provident savings | n.y.| , | , | , | , | . | | , | , | . | travelers' |conn.| , | , | , | , | . | | , | , | . | union mutual |maine| , | , | , | , | . | | , | , | . | united states | n.y.| , | , | , | , | . | | , | , | . | vermont | vt. | , | , | , | , | . | | , | | . | washington | n.y.| , | , | , | , | . | | , | , | . | | | | | | | | | | | | +-----+-----------+----------+-----------+-----------+-----+---+-----------+-----------+----+--- totals | |$ , , |$ , , |$ , , |$ , , | . | |$ , , | $ , , | . | _collective business of assessment societies doing business in the state (excepting secret societies_). societies | | $ , | | | $ , | . | | | | | ------------------------------------------------------------------------------------------------------------------- [footnote : including industrial business.] [footnote : includes $ . depreciation.] the figures given in this table are drawn from the last annual report of the insurance commissioner of massachusetts, excepting the premium reserve on death claims, which, as well as the division of the total expenses of each company into insurance and investment expenses, i have estimated on a uniform rule. this was for lack of the actual data in these particulars, which the report did not give, as it is desirable that future ones may. this, however, does not injure the value of the table for illustrating the mode of procedure, for which purpose mainly it is presented. the companies whose figures i have used, moreover, have no occasion to complain of this, as my estimate certainly gives all ratios of insurance expense lower than they would appear if i had known, and used, the exact actual premium reserve on death claims, and all probably bear nearly the same ratio to each other as they would in that case. as the object of this statement is to explain the new method, and not to defend my particular estimates in applying it, i forbear to state on what rules i have made them. expense which is not ascribed to insurance must be ascribed to investment, and as in comparing any two companies, their two ratios of one kind or the other must be equated, to decide the question of economy between them, it may well be left to any company to say what the fair division of its own expenses is. moreover, there can be but little motive to make a false division; for to successfully compete for business, a company having large investments has as much need to show a high net rate of interest earned as a low rate of insurance expense. again, it is not my purpose to pass judgment on the economy or extravagance of any ratio of expense shown in the table. it is not a fact exhibited for the first time by my figures, that the ratios of some companies are more than double those of others. the same fact would be displayed in about as high a degree by ratios based on premium income, or any other incorrect basis. custom, the balance of opinions, and competition may well be left to decide what ratios of expense are high, and what are average, or low. and their decision is to be gathered only from _statistics_. what i do claim is that the mode of determining ratios herein explained is the only intelligible and scientific one, and the only one proper to employ in _statistical tabulations_ and _investigations_. as such, it calls attention to the fact that the amount of insurance claims met, and of interest receipts, _are limits_ which the corresponding expenses cannot exceed, certainly for a series of years together, without making the _expense_ more than the _advantage_ of the business. to keep this fact in view, _as a preventive of extravagance_, is not the least valuable service the new mode may render. it may be seen that there are eight cases in the table, in which the ratio of insurance expense points to expenses exceeding the insurance claims met in the same time, yet the reader need not hasten to conclude that the same companies will permanently show similar ratios, or have no good reasons to give for the ones which now appear. i may remark, however, that it is an evidence of the scientific mode in which the figures are presented, that it facilitates such explanations as are pertinent of any of the ratios. for instance, some of the ratios are undoubtedly affected by the fact that the claims for the year of the company in question have been exceptionally high or low, or that the company (being of recent organization perhaps) has just incurred exceptional expense to increase its business, the advantage of which will appear later, etc. but i leave to the companies themselves to show to what extent such circumstances have affected their ratios; except that, in regard to the several net rates of interest earned, it is proper to say that in all cases in which they considerably exceed the average of . per cent. it will be found, by referring to the details of interest receipts reported to the commissioner, that the excess is owing to the fact of exceptional profits by the sale of stocks, or recovery on investments previously reckoned as loss. walter c. wright. medford, mass., sept., . * * * * * a catalogue containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . , stitched in paper, or $ . , bound in stiff covers. combined rates--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway, new york, n.y. * * * * * patents. in connection with the scientific american, messrs. munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats. trade marks, their costs, and how procured. address munn & co., broadway, new york. branch office, cor. f and th sts., washington, d.c. team at www.pgdp.net. [illustration] scientific american supplement no. new york, october , scientific american supplement. vol. xxxii, no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. anthropology.--the study of mankind.--a review of prof. max muller's recent address before the british association. ii. chemistry.--standards and methods for the polarimetric estimation of sugars.--a u.s. internal revenue report on the titular subject.-- illustrations. the formation of starch in leaves.--an interesting examination into the physiological _role_ of leaves.-- illustration. the water molecule.--by a. ganswindt.--a very interesting contribution to structural chemistry. iii. civil engineering.--demolition of rocks under water without explosives.--lobnitz system.--by edward s. crawley.--a method of removing rocks by combined dredging and ramming as applied on the suez canal.-- illustrations. iv. electricity.--electrical standards.--the english board of trade commission's standards of electrical measurements. the london-paris telephone.--by w.h. preece, f.r.s.--details of the telephone between london and paris and its remarkable success.-- illustrations. the manufacture of phosphorus by electricity.--a new industry based on dynamic electricity.--full details. the two or three phase alternating current systems.--by carl hering.--a new industrial development in electricity fully described and graphically developed.-- illustrations. v. geography and exploration.--the grand falls of labrador.--the bowdoin college exploring expedition and its adventures and discoveries in labrador. vi. mechanical engineering.--improved changeable speed gearing.--an ingenious method of obtaining different speeds at will from a single driving shaft.-- illustrations. progress in engineering.--notes on the progress of the last decade. vii. medicine and hygiene.--eyesight.--its care during infancy and youth.--by l. webster fox, m.d.--a very timely article on the preservation of sight and its deterioration among civilized people. the use of compressed air in conjunction with medicinal solutions in the treatment of nervous and mental affections.--by j. leonard corning.--the enhancement of the effects of remedies by subsequent application of compressed air. viii. mineralogy.--a gem-bearing granite vein in western connecticut.--by l.p. gratacap.--a most interesting mineral fissure yielding mica and gems recently opened. ix. natural history.--ants.--by ruth ward kahn.--an interesting presentation of the economy of ants. x. naval engineering.--armor plating on battleships--france and great britain.--a comparison of the protective systems of the french and english navies.-- illustrations. the redoutable.--an important member of the french mediterranean fleet described and illustrated.-- illustration. xi. technology.--new bleaching apparatus.--a newly invented apparatus for bleaching pulp.-- illustrations. * * * * * the redoutable. the central battery and barbette ship redoutable, illustrated this week, forms part of the french mediterranean squadron, and although launched as early as is still one of its most powerful ships. below are some of the principal dimensions and particulars of this ironclad: length ft. in. beam " " draught " " displacement tons. crew officers and men. [illustration: the french central battery ironclad redoutable.] the redoutable is built partly of iron and partly of steel and is similar in many respects to the ironclads devastation and courbet of the same fleet, although rather smaller. she is completely belted with in. armor, with a in. backing, and has the central battery armored with plates of ½ in. in thickness. the engines are two in number, horizontal, and of the compound two cylinder type, developing a horse power of , , which on the trial trip gave a speed of . knots per hour. five hundred and ten tons of coal are carried in the bunkers, which at a speed of knots should enable the ship to make a voyage of , knots. torpedo defense netting is fitted, and there are three masts with military tops carrying hotchkiss revolver machine guns. the offensive power of the ship consists of seven breechloading rifled guns of centimeters ( . in.), and weighing tons each, six breechloading rifled guns of centimeters ( . in.), and quick-firing and machine guns of the hotchkiss systems. there are in addition four torpedo discharge tubes, two on each side of the ship. the positions of the guns are as follows: four of centimeters in the central battery, two on each broadside; three centimeter guns on the upper deck in barbettes, one on each side amidships, and one aft. the centimeter guns are in various positions on the broadsides, and the machine guns are fitted on deck, on the bridges, and in the military tops, four of them also being mounted on what is rather a novelty in naval construction, a gallery running round the outside of the funnel, which was fitted when the ship was under repairs some months ago. there are three electric light projectors, one forward on the upper deck, one on the bridge just forward of the funnel, and one in the mizzen top.--_engineering._ * * * * * armor plating on battleships: france and great britain. the visit of the french squadron under admiral gervais to england has revived in many a nautical mind the recollection of that oft-repeated controversy as to the relative advantages of armored belts and citadels. now that a typical french battleship of the belted class has been brought so prominently to our notice, it may not be considered an inappropriate season to dwell shortly upon the various idiosyncrasies of thought which have produced, in our two nations, types of war vessels differing so materially from each other as to their protective features. in order to facilitate a study of these features, the accompanying sketch has been prepared, which shows at a glance the relative quantities of armored surface that afford protection to the nile, the camperdown, the marceau, the royal sovereign, and the dupuy de lôme; the first three of these vessels having been actually present at the review on the st of august and the two others having been selected as the latest efforts of shipbuilding skill in france and great britain. nothing but the armored surface in each several class is shown, the same scale having been adhered to in all cases. [illustration: armored surface for various ships] two impressions cannot fail to be made upon our minds, both as to french and british armor plate disposition. these two impressions, as regards great britain, point to the royal sovereign as embodying the idea of two protected stations with a narrow and partial connecting belt; and to the nile as embodying the idea of a vast and absolutely protected raft. for france, we have the marceau as representing the wholly belted type with four disconnected but protected stations; and the dupuy de lôme, in which the armor plating is thinned out to a substance of only in., so as entirely to cover the sides of the vessel down to ft, below the water line; this thickness of plating being regarded as sufficient to break up upon its surface the dreaded mélinite or guncotton shell, but permitting the passage of armor-piercing projectiles right through from side to side; provision being made to prevent damage from these latter to engines and vitals by means of double-armored decks below, with a belt of cellulose between them. thus, as we have explained, two prominent ideas are present in the disposition of armor upon the battleships of great britain, as well as in that of the battleships of france. but, while in our country these two ideas follow one another in the natural sequence of development, from the inflexible to the royal sovereign, the citadel being gradually extended into two redoubts, and space being left between the redoubts for an auxiliary battery--this latter being, however, singularly placed above the armored belt, and _not within its shelter_--in france, on the other hand, we find the second idea to be a new departure altogether in armored protection, or rather to be a return to the original thought which produced the gloire and vessels of her class. in point of fact, while we have always clung to the armored citadel, france has discarded the belt altogether, and gone in for speed and light armor, as well as for a much lighter class of armament. time alone, and the circumstances of actual warfare, can prove which nation has adopted the wisest alternative. a glance at the engraving will show the striking contrast between the existing service types as to armored surface. the marceau appears absolutely naked by the side of the solidly armed citadel of the nile. the contrast between the future types will be, of course, still more striking, for the reasons given in the last paragraph. but while remarking upon the paucity of heavy plating as exhibited in the service french battleships, we would say one word for the angle at which it is placed. the receding sides of the great vessels of france give two very important attributes in their favor. in the first place, a much broader platform at the water line is afforded to secure steadiness of the ship and stable equilibrium, and the angle at which the armor rests is so great as to present a very oblique surface to the impact of projectiles. the trajectory of modern rifled guns is so exceedingly flat that the angle of descent of the shot or shell is practically _nil_. were the sides of the royal sovereign to fall back like those of the marceau or magenta, we seriously doubt whether any projectile, however pointed, would effect penetration at all. we conclude, then, that a comparison of the marceau with the nile as regards protective features is so incontestably in favor of the latter, that they cannot be classed together for a moment. in speed, moreover, though this is not a point under consideration, the nile has the advantage. it is impossible, however, to avoid the conviction that the dupuy de lôme would be a most powerful and disagreeable enemy for either of the eight great ironclads of great britain now building to encounter on service. the hood and royal sovereign have many vulnerable points. at any position outside of the dark and light colored portions of armor plate indicated in our drawing, they could be hulled with impunity with the lightest weapons. it is true that gun detachments and ammunition will be secure within the internal "crinolines," but how about the other men and _matériel_ between decks? now, the dupuy de lôme may be riddled through and through bf a ½ in. shell if a royal sovereign ever succeeds in catching her; but from lighter weapons her between decks is almost secure. we cannot help feeling a sneaking admiration for the great french cruising battleship, with her , tons and , horse power, giving an easy speed of knots in almost any weather, and protected by a complete in. steel panoply, which will explode the shells of most of our secondary batteries on impact, or prevent their penetration. in fact, there is little doubt that the interior of the trafalgar, whether as regards the secondary batteries or the unarmored ends, would be probably found to be a safer and pleasanter situation, in the event of action with a dupuy de lôme, than either of the naked batteries or the upper works of the royal sovereign. this is what sir e.j. reed was so anxious to point out at the meeting of naval architects in , when he described the modern british battleship as a "spoiled trafalgar." there was perhaps some reason in what he said.--_the engineer._ * * * * * demolition of rocks under water without explosives-lobnitz system.[ ] [footnote : read before the engineer's club, philadelphia. translated from _nouvelles anodes de la construction,_ march, .] by edwin s. crawley. the methods of demolishing rocks by the use of explosives are always attended by a certain amount of danger, while at the same time there is always more or less uncertainty in regard to the final result of the operation. especially is this the case when the work must be carried on without interrupting navigation and in the vicinity of constructions that may receive injury from the explosions. such were the conditions imposed in enlarging the suez canal in certain parts where the ordinary dredges could not be used. mr. henry lobnitz, engineer at renfrew, has contrived a new method of procedure, designed for the purpose of enlarging and deepening the canal in those parts between the bitter lakes and suez, where it runs over a rocky bed. it was necessary to execute the work without interrupting or obstructing traffic on the canal. the principle of the system consists in producing a shattering of the rock by the action of a heavy mass let fall from a convenient height, and acting like a projectile of artillery upon the wall of a fortress. from experiments made in the quarry of craigmiller, near edinburgh, with a weight of two tons shod with a steel point, it was found that with a fall of about . meters ( . ft.) there was broken up on an average more than . cubic meter ( . cubic yard) of hard rock per blow. the first blow, delivered centimeters ( ft. ½ in.) from the wall face, produced an almost imperceptible rent, a second or a third blow applied at the same place extended this opening often to a length of . meters ( ft. in.) and to a depth of from to centimeters ( ft. in. to ft. in.) the next blow opened the fissure and detached the block of rock. the application of the same system under water upon an unknown surface would obviously modify the conditions of the experiment. nevertheless, the results obtained with the "derocheuse," the first dredging machine constructed upon this principle, have realized the hopes of the inventor. this dredging machine was launched on the clyde and reached port said in twenty days. it measures meters ( ft. in.) in length, . meters ( ft. in.) in breadth, and . meters ( ft.) in depth. its mean draught of water is . meters ( ft. ½ in.) it is divided into eighteen watertight compartments. five steel-pointed battering rams, each of four tons weight, are arranged in line upon each side of the chain of buckets of the dredging machine. see figs. and . the battering rams, suspended by chains, are raised by hydraulic power to a height varying from . to meters ( ft. in. to ft. in.), and are then let fall upon the rock. the mechanism of the battering rams is carried by a metallic cage which can be moved forward or backward by the aid of steam as the needs of the work require. a series of five battering rams gives from to blows per hour. [illustration: fig. .--longitudinal section.] [illustration: fig. .--plan] a dredging machine combined with the apparatus just described, raises the fragments of rock as they are detached from the bottom. a guide wheel is provided, which supports the chain carrying the buckets, and thus diminishes the stress upon the axles and bearings. with this guide wheel or auxiliary drum there is no difficulty in dredging to a depth of meters ( ft. in.), while without this accessory it is difficult to attain a depth of meters ( ft. in.) a compound engine, with four cylinders of indicated horse power, drives, by means of friction gear, the chain, which carries the buckets. if the buckets happen to strike against the rock, the friction gear yields until the excess of resistance has disappeared. fig. indicates the manner in which the dredge is operated during the work. it turns alternately about two spuds which are thrust successively into the bottom and about which the dredge describes a series of arcs in a zigzag fashion. these spuds are worked by hydraulic power. a three ton hand crane is placed upon the bridge for use in making repairs to the chain which carries the buckets. a six ton steam crane is placed upon the top of the cage which supports the hydraulic apparatus for raising the battering rams, thus permitting them to be easily lifted and replaced. the dredging machine is also furnished with two screws driven by an engine of indicated horse power, as well as with two independent boilers. two independent series of pumps, with separate connections, feed the hydraulic lifting apparatus, thus permitting repairs to be made when necessary, without interrupting the work. a special machine with three cylinders drives the pumps of the condenser. an accumulator regulates the hydraulic pressure and serves to raise or lower the spuds. at the end of the suez canal next to the red sea, the bottom consists of various conglomerates containing gypsum, sandstone and sometimes shells. it was upon a bed of this nature that the machine was first put to work. the mean depth of water, originally . meters ( ft. in.), was for a long time sufficient for the traffic of the canal; but as the variations in level of the red sea are from . to meters ( ft. in. to ft. in.), the depth at the moment of low water is scarcely adequate for the constantly increasing draught of water of the steamers. attempts were made to attack the rocky surface of the bottom with powerful dredges, but this method was expensive because it necessitated constant repairs to the dredges. [illustration: fig. .--dredge movement.] these last, although of good construction, seldom raised more than cubic meters ( cubic yards) in from eight to fifteen days. their daily advance was often only from sixty to ninety centimeters (about to ft.), while with the "derocheuse" it was possible to advance ten times as rapidly in dredging to the same depth. the bottom upon which the machine commenced its work was clean and of a true rocky nature. it was soon perceived that this conglomerate, rich in gypsum, possessed too great elasticity for the pointed battering rams to have their proper effect upon it. each blow made a hole of from fifteen to sixty centimeters ( in. to . ft.) in depth. a second blow, given even very near to the first, formed a similar hole, leaving the bed of the rock to all appearances intact between the two holes. this result, due entirely to the special nature of the rock, led to the fear that the action of the battering rams would be without effect. after some experimentation it was found that the best results were obtained by arranging the battering rams very near to the chain of buckets and by working the dredge and battering rams simultaneously. the advance at each oscillation was about centimeters (about ft.) the results obtained were as follows: at first the quantity extracted varied much from day to day; but at the end of some weeks, on account of the greater experience of the crew, more regularity was obtained. the nature of the conglomerate was essentially variable, sometimes hard and tenacious, like malleable iron, then suddenly changing into friable masses surrounded by portions more elastic and richer in gypsum. during the last five weeks at port tewfik, the expense, including the repairs, was , francs ($ , . ) for , cubic meters ( , cubic yards) extracted. this would make the cost . francs per cubic meter, or $ . per cubic yard, not including the insurance, the interest and the depreciation of the plant. after some improvements in details, suggested by practice, the machine was put in operation at chalouf upon a hard rock, from . to meters ( ft. in. to ft. in.) thick. the battering rams were given a fall of . meters ( ft. in.). to break the rock into fragments small enough not to be rejected by the buckets of the dredge, the operations of dredging and of disintegration were carried on separately, permitting the battering rams to work at a greater distance from the wall face. the time consumed in thus pulverizing the rock by repeated blows was naturally found to be increased. it was found more convenient to use only a single row of battering rams. the production was from about seven to eleven cubic meters ( . to . cubic yards) per hour. toward the close of september, after it had been demonstrated that the "derocheuse" was capable of accomplishing with celerity and economy the result for which it was designed, it was purchased by the suez canal company. during the month of september, an experiment, the details of which were carefully noted, extending over a period of sixteen days, gave the following results: crew ( men), hours. , . francs $ . coal, @ . francs ($ . ) per ton . francs . oil and supplies . francs . fresh water, days . francs . sundries . francs . ---------------- --------- total expense for removing cubic meters ( . cubic yards), , . francs $ . average, . francs per cubic meter ($ . per cubic yard). this result cannot be taken as a universal basis, because after a year's use there are numerous repairs to make to the plant, which would increase the average net cost. this, besides, does not include the cost of removal of the dredged material, nor the depreciation, the interest and the insurance. it should be added on the other hand, however, that the warm season was far from being favorable to the energy and perseverance necessary to carry on successfully experiments of this kind. the temperature, even at midnight, was often ° c. ( . ° f.). still further, the work was constantly interrupted by the passage of ships through the canal. on an average not more than forty minutes' work to the hour was obtained. notwithstanding this, there were extracted at chalouf, on an average, . cubic meters ( cubic yards) per day without interrupting navigation. at port tewfik, where there was much less inconvenience from the passage of ships, the work was carried on from eight to eleven hours per day and the quantity extracted in this time was generally more than cubic meters ( . cubic yards). in most cases the system could be simplified. the engine which works the dredge could, when not thus employed, be used to drive the pumps. the propelling engine could also be used for the same purpose. the results obtained at suez indicate the appreciable advantages arising from the application of this system to the works of ports, rivers and canals, and ever, to the work of cutting in the construction of roads and railroads. * * * * * progress in engineering. mr. t. forster brown, in his address to the mechanical science section of the british association, said that great progress had been made in mechanical science since the british association met in the principality of wales eleven years ago; and some of the results of that progress were exemplified in our locomotives, and marine engineering, and in such works as the severn tunnel, the forth and tay bridges, and the manchester ship canal, which was now in progress of construction. in mining, the progress had been slow, and it was a remarkable fact that, with the exception of pumping, the machinery in use in connection with mining operations in great britain had not, in regard to economy, advanced so rapidly as had been the case in our manufactures and marine. this was probably due, in metalliferous mining, to the uncertain nature of the mineral deposits not affording any adequate security to adventurers that the increased cost of adopting improved appliances would be reimbursed; while in coal mining, the cheapness of fuel, the large proportion which manual labor bore to the total cost of producing coal, and the necessity for producing large outputs with the simplest appliances, explained the reluctance with which high pressure steam compound engines, and other modes embracing the most modern and approved types of economizing power had been adopted. metalliferous mining, with the exception of the working of iron ore, was not in a prosperous condition; but in special localities, where the deposits of minerals were rich and profitable, progress had been made within a recent period by the adoption of more economical and efficient machinery, of which the speaker quoted a number of examples. reference was also made to the rapid strides made in the use of electricity as a motive power, and to the mechanical ventilation of mines by exhaustion of the air. coal mines. summarizing the position of mechanical science, as applied to the coal mining industry in this country, mr. brown observed that there was a general awakening to the necessity of adopting, in the newer and deeper mines, more economical appliances. it was true it would be impracticable, and probably unwise, to alter much of the existing machinery, but, by the adoption of the best known types of electrical plant, and air compression in our new and deep mines, the consumption of coal per horse power would be reduced, and the extra expense, due to natural causes, of producing minerals from greater depths would be substantially lessened. the consumption of coal at the collieries of great britain alone probably exceeded , , tons per annum, and the consumption per horse power was probably not less than lb. of coal, and it was not unreasonable to assume that, by the adoption of more efficient machinery than was at present in general use, at least one-half of the coal consumed could be saved. there was, therefore, in the mines of great britain alone a wide and lucrative field for the inventive ingenuity of mechanical engineers in economizing fuel, and especially in the successful application of new methods for dealing with underground haulage, in the inner workings of our collieries, more especially in south wales, where the number of horses still employed was very large. steam trams and electric trams. considerable progress had within recent years been made in the mechanical appliances intended to replace horses on our public tram lines. the steam engine now in use in some of our towns had its drawbacks as as well as its good qualities, as also had the endless rope haulage, and in the case of the latter system, anxiety must be felt when the ropes showed signs of wear. the electrically driven trams appeared to work well. he had not, however, seen any published data bearing on the relative cost per mile of these several systems, and this information, when obtained, would be of interest. at the present time, he understood, exhaustive trials were being made with an ammonia gas engine, which, it was anticipated, would prove both more economical and efficient than horses for tram roads. the gas was said to be produced from the pure ammonia, obtained by distillation from commercial ammonia, and was given off at a pressure varying from to lb. per square inch. this ammonia was used in specially constructed engines, and was then exhausted into a tank containing water, which brought it back into its original form of commercial ammonia, ready for redistillation, and, it was stated, with a comparatively small loss. * * * * * improved changeable speed gearing. this is the invention of lawrence heath, of macedon, n.y., and relates to that class of changeable speed gearing in which a center pinion driven at a constant rate of speed drives directly and at different rates of speed a series of pinions mounted in a surrounding revoluble case or shell, so that by turning the shell one or another of the secondary pinions may be brought into operative relation to the parts to be driven therefrom. the aim of my invention is to so modify this system of gearing that the secondary pinions may receive a very slow motion in relation to that of the primary driving shaft, whereby the gearing is the better adapted for the driving of the fertilizer-distributers of grain drills from the main axle, and for other special uses. fig. is a side elevation. fig. is a vertical cross section. [illustration: fig. .] [illustration: fig. .] a represents the main driving shaft or axle, driven constantly and at a uniform speed, and b is the pinion-supporting case or shell, mounted loosely on and revoluble around the axle, but held normally at rest by means of a locking bolt, c, or other suitable locking device adapted to enter notches, _c_, in the shell. d is the primary driving pinion, fixed firmly to the axle and constantly engaging the pinion, e, mounted on a stud in the shell. the pinion, e, is formed integral with or firmly secured to the smaller secondary pinion, f, which in turn constantly engages and drives the center pinion, g, mounted to turn loosely on the axle within the shell, so that it is turned in the same direction as the axle, but at a slower speed. f', f_{ }, f_{ }, f_{ }, etc., represent additional secondary pinions grouped around the center pinion, mounted on studs in the shell, and made of different diameters, so that they are driven by the center pinion at different speeds. each of the secondary pinions is formed with a neck or journal, _f_, projected out through the side of the shell, so that the external pinion, h, may be applied to any one of the necks at will in order to communicate motion thence to the gear, i, which occupies a fixed position, and from which the fertilizer or other mechanism is driven. in order to drive the gear, i, at one speed or another, as may be demanded, it is only necessary to apply the pinion, h, to the neck of that secondary pinion which is turning at the appropriate speed and then turn the shell bodily around the axle until the external pinion is carried into engagement with gear i, when the shell is again locked fast. the axle communicates motion through d, e, and p to the center pinion, which in turn drives all the secondary pinions except f. if the external pinion is applied to f, it will receive motion directly therefrom; but if applied to either of the secondary pinions, it will receive motion through or by way of the center pinion. it will be seen that all the pinions are sustained and protected within the shell. the essence of the invention lies in the introduction of the pinions d and e between the axle and the series of secondary pinions to reduce the speed. * * * * * electrical standards. _nature_ states that the queen's printers are now issuing the report (dated july , ) to the president of the board of trade, of the committee appointed to consider the question of constructing standards for the measurement of electricity. the committee included mr. courtenay boyle, c.b., major p. cardew, r.e., mr. e. graves, mr. w.h. preece, f.r.s., sir w. thomson, f.r.s., lord rayleigh, f.r.s., prof. g. carey foster, f.r.s., mr. r.t. glazebrook, f.r. s., dr. john hopkinson, f.r.s., prof. w.e. ayrton, f.r.s. in response to an invitation, the following gentlemen attended and gave evidence: on behalf of the association of chambers of commerce, mr. thomas parker and mr. hugh erat harrison; on behalf of the london council, prof. silvanus thompson; on behalf of the london chamber of commerce, mr. r. e. crompton. the committee were indebted to dr. j.a. fleming and dr. a. muirhead for valuable information and assistance; and they state that they had the advantage of the experience and advice of mr. h. j. chaney, the superintendent of weights and measures. the secretary to the committee was sir t.w. p. blomefield, bart. the following are the resolutions of the committee: _resolutions._ ( ) that it is desirable that new denominations of standards for the measurement of electricity should be made and approved by her majesty in council as board of trade standards. ( ) that the magnitudes of these standards should be determined on the electro-magnetic system of measurement with reference to the centimeter as unit of length, the gramme as unit of mass, and the second as unit of time, and that by the terms centimeter and gramme are meant the standards of those denominations deposited with the board of trade. ( ) that the standard of electrical resistance should be denominated the ohm, and should have the value , , , in terms of the centimeter and second. ( ) that the resistance offered to an unvarying electric current by a column of mercury of a constant cross sectional area of square millimeter, and of a length of . centimeters at the temperature of melting ice may be adopted as ohm. ( ) that the value of the standard of resistance constructed by a committee of the british association for the advancement of science in the years and , and known as the british association unit, may be taken as . of the ohm. ( ) that a material standard, constructed in solid metal, and verified by comparison with the british association unit, should be adopted as the standard ohm. ( ) that for the purpose of replacing the standard, if lost, destroyed, or damaged, and for ordinary use, a limited number of copies should be constructed, which should be periodically compared with the standard ohm and with the british association unit. ( ) that resistances constructed in solid metal should be adopted as board of trade standards for multiples and sub-multiples of the ohm. ( ) that the standard of electrical current should be denominated the ampere, and should have the value one-tenth ( . ) in terms of the centimeter, gramme, and second. ( ) that an unvarying current which, when passed through a solution of nitrate of silver in water, in accordance with the specification attached to this report, deposits silver at the rate of . of a gramme per second, may be taken as a current of ampere. ( ) that an alternating current of ampere shall mean a current such that the square root of the time-average of the square of its strength at each instant in amperes is unity. ( ) that instruments constructed on the principle of the balance, in which, by the proper disposition of the conductors, forces of attraction and repulsion are produced, which depend upon the amount of current passing, and are balanced by known weights, should be adopted as the board of trade standards for the measurement of current, whether unvarying or alternating. ( ) that the standard of electrical pressure should be denominated the volt, being the pressure which, if steadily applied to a conductor whose resistance is ohm, will produce a current of ampere. ( ) that the electrical pressure at a temperature of ° f. between the poles or electrodes of the voltaic cell known as clark's cell may be taken as not differing from a pressure of . volts by more than an amount which will be determined by a sub-committee appointed to investigate the question, who will prepare a specification for the construction and use of the cell. ( ) that an alternating pressure of volt shall mean a pressure such that the square root of the time average of the square of its value at each instant in volts is unity. ( ) that instruments constructed on the principle of sir w. thomson's quadrant electrometer used idiostatically, and for high pressure instruments on the principle of the balance, electrostatic forces being balanced against a known weight, should be adopted as board of trade standards for the measurement of pressure, whether unvarying or alternating. we have adopted the system of electrical units originally defined by the british association for the advancement of science, and we have found in its recent researches, as well as in the deliberations of the international congress on electrical units, held in paris, valuable guidance for determining the exact magnitudes of the several units of electrical measurement, as well as for the verification of the material standards. we have stated the relation between the proposed standard ohm and the unit of resistance originally determined by the british association, and have also stated its relation to the mercurial standard adopted by the international conference. we find that considerations of practical importance make it undesirable to adopt a mercurial standard; we have, therefore, preferred to adopt a material standard constructed in solid metal. it appears to us to be necessary that in transactions between buyer and seller, a legal character should henceforth be assigned to the units of electrical measurement now suggested; and with this view, that the issue of an order in council should be recommended, under the weights and measures act, in the form annexed to this report. _specification referred to in resolution ._ in the following specification the term silver voltameter means the arrangement of apparatus by means of which an electric current is passed through a solution of nitrate of silver in water. the silver voltameter measures the total electrical quantity which has passed during the time of the experiment, and by noting this time the time average of the current, or if the current has been kept constant, the current itself, can be deduced. in employing the silver voltameter to measure currents of about ampere, the following arrangements should be adopted. the kathode on which the silver is to be deposited should take the form of a platinum bowl not less than cm. in diameter, and from to cm. in depth. the anode should be a plate of pure silver some square cm. in area and or millimeters in thickness. this is supported horizontally in the liquid near the top of the solution by a platinum wire passed through holes in the plate at opposite corners. to prevent the disintegrated silver which is formed on the anode from falling on to the kathode, the anode should be wrapped round with pure filter paper, secured at the back with sealing wax. the liquid should consist of a neutral solution of pure silver nitrate, containing about parts by weight of the nitrate to parts of water. the resistance of the voltameter changes somewhat as the current passes. to prevent these changes having too great an effect on the current, some resistance besides that of the voltameter should be inserted in the circuit. the total metallic resistance of the circuit should not be less than ohms. _method of making a measurement._--the platinum bowl is washed with nitric acid and distilled water, dried by heat, and then left to cool in a desiccator. when thoroughly dry, it is weighed carefully. it is nearly filled with the solution, and connected to the rest of the circuit by being placed on a clean copper support, to which a binding screw is attached. this copper support must be insulated. the anode is then immersed in the solution, so as to be well covered by it, and supported in that position; the connections to the rest of the circuit are made. contact is made at the key, noting the time of contact. the current is allowed to pass for not less than half an hour, and the time at which contact is broken is observed. care must be taken that the clock used is keeping correct time during this interval. the solution is now removed from the bowl, and the deposit is washed with distilled water and left to soak for at least six hours. it is then rinsed successively with distilled water and absolute alcohol, and dried in a hot-air bath at a temperature of about ° c. after cooling in a desiccator, it is weighed again. the gain in weight gives the silver deposited. to find the current in amperes, this weight, expressed in grammes, must be divided by the number of seconds during which the current has been passed, and by . . the result will be the time average of the current, if during the interval the current has varied. in determining by this method the constant of an instrument the current should be kept as nearly constant as possible, and the readings of the instrument taken at frequent observed intervals of time. these observations give a curve from which the reading corresponding to the mean current (time average of the current) can be found. the current, as calculated by the voltameter, corresponds to this reading. * * * * * the two or three phase alternating current systems. by carl hering. the occasion of the transmission of power from lauffen to frankfort has brought to the notice of the profession more than ever before the two or three phase alternating current system, described as early as - by various electricians, among whom are tesla, bradley, haselwander and others. as to who first invented it, we have nothing to say here, but though known for some years it has not until quite recently been of any great importance in practice. within the last few years, however, mr. m. von dolivo-dobrowolsky, electrical engineer of the allgemeine elektricitats gesellschaft, of berlin, has occupied himself with these currents. his success with motors run with such currents was the origin of the present great transmission of power exhibit at frankfort, the greatest transmission ever attempted. his investigation in this new sphere, and his ability to master the subject from a theoretical or mathematical standpoint, has led him to find the objections, the theoretically best conditions, etc. this, together with his ingenuity, has led him to devise an entirely new and very ingenious modification, which will no doubt have a very great effect on the development of alternating current motors. it is doubtless well known that if, as in fig. , a gramme ring armature is connected to leads at four points as shown and a magnet is revolved inside of it (or if the ring is revolved in a magnetic field and the current led off by contact rings instead of a commutator), there will be two alternating currents generated, which will differ from each other in their phases only. when one is at a maximum the other is zero. when such a double current is sent into a similarly constructed motor it will produce or generate what might be called a rotary field, which is shown diagrammatically in the six successive positions in fig. . the winding here is slightly different, but it amounts to the same thing as far as we are concerned at present. this is what mr. dobrowolsky calls an "elementary" or "simply" rotary current, as used in the tesla motors. a similar system, but having three different currents instead of two, is the one used in the lauffen transmission experiment referred to above. [illustration: fig. .] [illustration: fig. .] in investigating this subject mr. dobrowolsky found that the best theoretical indications for such a system would be a large number of circuits instead of only two or three, each differing from the next one by only a small portion of a wave length; the larger their number the better theoretically. the reason is that with a few currents the resulting magnetism generated in the motor by these currents will pulsate considerably, as shown in fig. , in which the two full lines show the currents differing by degrees. the dotted line above these shows how much the resulting magnetism will pulsate. with two such currents this variation in magnetism will be about degrees above its lowest value. now, such a variation in the field is undesirable, as it produces objectionable induction effects, and it has the evil effect of interfering with the starting of the motor loaded, besides affecting the torque considerably if the speed should fall slightly below that for synchronism. a perfect motor should not have these faults, and it is designed to obviate them by striving to obtain a revolving field in which the magnetism is as nearly constant as possible. [illustration: fig. .] if there are two currents differing by degrees, this variation of the magnetism will be about per cent.; with three currents differing degrees, about per cent; with six currents differing degrees it will be only about per cent., and so on. it will be seen, therefore, that by doubling the three-phase system the pulsations are already very greatly reduced. but this would require six wires, while the three-phase system requires only three wires (as each of the three leads can readily be shown to serve as a return lead for the other two in parallel). it is to combine the advantages of both that he designed the following very ingenious system. by this system he can obtain as small a difference of phase as desired, without increasing the number of wires above three, a statement which might at first seem paradoxical. before explaining this ingenious system, it might be well to call attention to a parallel case to the above in continuous current machines and motors. the first dynamos were constructed with two commutator bars. they were soon found to work much better with four, and finally still better as the number of commutator bars (or coils) was increased, up to a practical limit. just as the pulsations in the continuous current dynamos were detrimental to proper working, so are these pulsations in few-phased alternating current motors, though the objections manifest themselves in different ways--in the continuous current motors as sparking and in the alternating current motors as detrimental inductive effects. the underlying principle of this new system may be seen best in figs. , , , and . in fig. are shown two currents, i_{ } and i_{ }, which differ from each other by an angle, d. suppose these two currents to be any neighboring currents in a simple rotary current system. now, if these two currents be united into one, as shown in the lower part of the figure, the resulting current, i, will be about as shown by the dotted line; that is, it will lie between the other two and at its maximum point, and for a difference of phases equal to degrees it will be about . times as great as the maximum of either of the others; the important feature is that the phase of this current is midway between that of the other two. fig. shows the winding of a cylinder armature and fig. that, of a gramme armature for a simple three-phase current with three leads, with which system we assume that the reader is familiar. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] the two figures, and (or ), correspond with each other in so far as the currents in the three leads, shown in heavy lines, have a phase between those of the two which compose them. referring now to fig. (or ), which is precisely like fig. (or ), except that it has an additional winding shown in heavy lines, it will be seen that each of the three leads, shown in heavy lines, is wound around the armature before leaving it, forming an additional coil lying _between_ the two coils with which it is in series. the phase of the heavy line currents was shown in fig. to lie between the other two. therefore, in the armature in fig. (or ) there will be six phases, while in fig. there are only three, the number of leads (three) remaining the same as before. this is the fundamental principle of this ingenious invention. to have six phases in fig. would require six leads, but in fig. precisely the same result is obtained with only three leads. in the same way the three leads in fig. might again be combined and passed around the armature again, and so on forming still more phases, without increasing the number of leads. figs. and compound with and and show the same system for a gramme ring instead of a cylinder armature. as was stated in the early part of this description, the main object in a rotary current motor is to have a magnetic field which is as nearly constant in intensity as possible, and which changes only its position, that is, its axis. but in fig. it was shown that the current i (in dotted lines) is greater than the others (about as . to for a phase difference of degrees). if therefore the coils in fig. or were all alike, the magnetism generated by the heavy line coils would be greater than that generated by the others, and would therefore produce very undesirable pulsations in the magnetic fields; but as the magnetism depends on the ampere turns, it is necessary merely to have correspondingly fewer turns on these coils, as compared with the others. this is shown diagrammatically in figs. and , in which the heavy line coils have less windings than the others. in practice it is not always possible to obtain the exact ratio of to . , for instance, but even if this ratio is obtained only approximately, it nevertheless reduces the pulsations very materially below what they would be with half the number of phases. it is therefore not necessary in practice to have more than an approximation to the exact conditions. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] fig. shows a multiple phase armature having double the number of phases as fig. , and would according to the old system, therefore, require eight leads. fig. shows the new system with the same number of phases as in fig. , but requiring only four leads instead of eight. figs. and correspond with figs. and and show the windings for a multipolar motor in the two systems. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] these figures show how a motor may be wound so as to be a multiple phase motor, although the current entering the motor is a simple, elementary three or two phase current, which can be transformed by means of a simple three or two phase current transformer, before entering the motor, such transformers as are used at present in the lauffen-frankfort transmission. but the same principle as that for the motor may also be applied to transformers themselves, as shown in figs. and . fig. shows a set of transformers which are fed by a simple three-phase current shown in heavy lines, and which gives in its secondary circuit a multiple phase rotary current. the connections for the primary circuit of a transformer with six coils are shown diagrammatically in fig. , the numbers to representing the succession of the phases. fig. shows a transformer for a two-phase current with four leads, transforming into a multiple phase current of leads. the transformer in this figure is a single "interlocked" transformer in which the fields are magnetically connected and not independent of each other as in fig. . this has advantages in the regulation of currents, which do not exist in fig. , but which need not be entered into here. the transformers used in the lauffen-frankfort transmission are similar, magnetically, to fig. , only that they are for a simple three-phase current in both primary and secondary circuits. attention is also called to the difference in the connections of secondary circuits in figs. and ; in the former they are connected in a closed circuit similarly to an ordinary closed circuit armature, while in fig. they are independent as far as the currents themselves are concerned, though magnetically their cores are connected. it is not the intention to enter into a discussion of the relative values of these various connections, but merely to draw attention to the wide range of the number of combinations which this system admits of.--_electrical world_. * * * * * the london paris telephone.[ ] [footnote : paper read before the british association.--_elec. engineer._] by w.h. preece, f.r.s. . i have already on two occasions, at newcastle and at leeds, brought this subject before section g, and have given the details of the length and construction of the proposed circuit. i have now to report not only that the line has been constructed and opened to the public, but that its success, telephonic and commercial, has exceeded the most sanguine anticipations. speech has been maintained with perfect clearness and accuracy. the line has proved to be much better than it ought to have been, and the purpose of this paper is to show the reason why. the lengths of the different sections of the circuit are as follows: london to st. margaret's bay . miles. st. margaret's bay to sangatte (cable). . " sangatte to paris. . " paris underground. . " ----- total. . " the resistances are as follows: paris underground. ohms. french line. " cable. " english line. " --- total (r) " the capacities are as follows: paris underground. . microfarads. french line. . " cable. . " english line. . " ---- total (k). . " × . = , = k r a product which indicates that speech should be very good. . _trials of apparatus._--the preliminary trials were made during the month of march between the chief telegraph offices of the two capitals, and the following microphone transmitters were compared: ader. pencil form. berliner. granular form. d'arsonval. pencil " dejongh. " " gower bell. " " post office switch instrument. granules and lamp filaments. roulez. lamp filaments. turnbull. pencil form. western electric. granular. the receivers consisted of the latest form of double-pole bell telephones with some ader and d'arsonval receivers for comparison. after repeated trials it was finally decided that the ader, d'arsonval, gower-bell (with double-pole receivers instead of tubes), roulez, and western electric were the best, and were approximately equal. these instruments were, therefore, selected for the further experiments, which consisted of using local extensions in paris and london. the wires were in the first instance extended at the paris end to the observatory through an exchange at the avenue des gobelines. the length of this local line is kms. the wires are guttapercha-covered, placed underground, and not suitable for giving the best results. the results were, however, fairly satisfactory. the wires were extended to the treasury in london by means of the ordinary underground system. the distance is about two miles, and although the volume of sound and clearness of articulation were perceptibly reduced by these additions to the circuit, conversation was quite practicable. further trials were also made from the avenue des gobelines on underground wires of five kilometers long, and also with some renters in paris with fairly satisfactory results. the selected telephones were equally efficient in all cases, which proves that to maintain easy conversation when the trunk wires are extended to local points it is only necessary that the local lines shall be of a standard not lower than that of the trunk line. the experiments also confirm the conclusion that long-distance speaking is solely a question of the circuit and its environments, and not one of apparatus. the instruments finally selected for actual work were gower-bell for london and roulez for paris. . the results are certainly most satisfactory. there is no circuit in or out of london on which speech is more perfect than it is between london and paris. in fact, it is better than i anticipated, and better than calculation led me to expect. speech has been possible not only to paris but through paris to bruxelles, and even, with difficulty, through paris to marseilles, a distance of over miles. the wires between paris and marseilles are massive copper wires specially erected for telephone business between those important places. . _business done._--the charge for a conversation between london and paris is s. for three minutes' complete use of the wire. the demand for the wire is very considerable. the average number of talks per day, exclusive of sunday, is . the maximum has been . we have had as many as per hour--the average is during the busy hours of the day. as an instance of what can be done, words per minute have been dictated in paris and transcribed in london by shorthand writing. thus in three minutes words were recorded, which at s. cost five words for a penny. . _difficulties._--the difficulties met with in long-distance speaking are several, and they may be divided into (a) those due to external disturbances and (b) those due to internal opposition. (_a._) every current rising and falling in the neighborhood of a telephone line within a region, say, of yards, whether the wire conveying it be underground or overground, induces in the telephone circuit another current, producing in the telephone a sound which disturbs speech, and if the neighboring wires are numerous and busy, as they are on our roads and railways, these sounds became confusing, noisy, and ultimately entirely preventive of speech. this disturbance is, however, completely removed by forming the telephone circuit of two wires placed as near to each other as possible, and twisted around each other without touching, so as to maintain the mean average distance of each wire from surrounding conductors the same everywhere. thus similar currents are induced in each of the two wires, but being opposite in direction, as far as the circuit is concerned, they neutralize each other, and the circuit, therefore, becomes quite silent. in england we make the two wires revolve completely round each other in every four poles, but in france it is done in every six poles. the reason for the change is the fact that in the english plan the actual crossing of the wires takes place in the span between the poles, while in the french plan it takes place at the poles. this is supposed to reduce the liability of the wires to be thrown into contact with each other by the wind, but, on the other hand, it diminishes the geometrical symmetry of the wires--so very essential to insure silence. as a matter of fact, contacts do not occur on well constructed lines, and i think our english wires, being more symmetrical, are freer from external disturbance than those in france. [illustration: fig. .] (_b._) the internal opposition arises from the resistance, r, the capacity, k, and the electromagnetic inertia, l, of the circuit. a current of electricity takes time to rise to its maximum strength and time to fall back again to zero. every circuit has what is called its time constant, _t_, fig. , which regulates the number of current waves which can be transmitted through it per second. this is the time the current takes to rise from zero to its working maximum, and the time it takes to fall from this maximum to zero again, shown by the shaded portions of the figure; the duration of the working current being immaterial, and shown by the unshaded portion. the most rapid form of quick telegraphy requires about currents per second, currents each of which must rise and fall in / of a second, but for ordinary telephone speaking we must have about , currents per second, or the time which each current rises from zero to its maximum intensity must not exceed / part of a second. the time constant of a telephone circuit should therefore not be less than . second. resistance alone does not affect the time constant. it diminishes the intensity or strength of the currents only; but resistance, combined with electromagnetic inertia and with capacity, has a serious retarding effect on the rate of rise and fall of the currents. they increase the time constant and introduce a slowness which may be called retardance, for they diminish the rate at which currents can be transmitted. now the retardance due to electromagnetic inertia increases directly with the amount of electromagnetic inertia present, but it diminishes with the amount of resistance of the conductor. it is expressed by the ratio l/r while that due to capacity increases directly, both with the capacity and with the resistance, and it is expressed by the product, k r. the whole retardance, and, therefore, the speed of working the circuit or the clearness of speech, is given, by the equation l --- + k r = t r or l + k r² = r t now in telegraphy we are not able altogether to eliminate l, but we can counteract it, and if we can make rt = , then l = - k r² which is the principle of the shunted condenser that has been introduced with such signal success in our post office service, and has virtually doubled the carrying capacity of our wires. k r = t this is done in telephony, and hence we obtain the law of retardance, or the law by which we can calculate the distance to which speech is possible. all my calculations for the london and paris line were based on this law, which experience has shown it to be true. how is electromagnetic inertia practically eliminated? first, by the use of two massive copper wires, and secondly by symmetrically revolving them around each other. now l depends on the geometry of the circuit, that is, on the relative form and position of the different parts of the circuit, which is invariable for the same circuit, and is represented by a coefficient, [lambda]. it depends also on the magnetic qualities of the conductors employed and of the space embraced by the circuit. this specific magnetic capacity is a variable quantity, and is indicated by [mu] for the conductor and by [mu]_{ } for air. it depends also on the rate at which currents rise and fall, and this is indicated by the differential coefficient dc / dt. it depends finally on the number of lines of force due to its own current which cut the conductor in the proper direction; this is indicated by [beta]. combining these together we can represent the electromagnetic inertia of a metallic telephone circuit as l = [lambda] ([mu] + [mu]_{ }) dc/dt × [beta] now, [lambda] = log (d²/a²) hence the smaller we make the distance, _d_, between the wires, and the greater we make their diameter, _a_, the smaller becomes [lambda]. it is customary to call the value of [mu] for air, and copper, , but this is purely artificial and certainly not true. it must be very much less than one in every medium, excepting the magnetic metals, so much so that in copper it may be neglected altogether, while in the air it does not matter what it is, for by the method of twisting one conductor round the other, the magnetization of the air space by the one current of the circuit rotating in one direction is exactly neutralized by that of the other element of the circuit rotating in the opposite direction. now, [beta], in two parallel conductors conveying currents of the same sense, that is flowing in the same direction, is retarding, fig. , and is therefore a positive quantity, but when the currents flow in opposite directions, as in a metallic loop, fig. , they tend to assist each other and are of a negative character. hence in a metallic telephone circuit we may neglect l _in toto_ as i have done. [illustration: fig .] [illustration: fig. .] i have never yet succeeded in tracing any evidence of electromagnetic inertia in long single copper wires, while in iron wires the value of l may certainly be taken at . henry per mile. in short metallic circuits, say of lengths up to miles, this negative quantity does not appear, but in the paris-london circuit this helpful mutual action of opposite currents comes on in a peculiar way. the presence of the cable introduces a large capacity practically in the center of the circuit. the result is that we have in each branch of the circuit between the transmitter, say, at london and the cable at dover, extra currents at the commencement of the operation, which, flowing in opposite directions, mutually react on each other, and practically prepare the way for the working currents. the presence of these currents proved by the fact that when the cable is disconnected at calais, as shown in fig. , and telephones are inserted in series, as shown at d and d', speech is as perfect between london and st. margaret's bay as if the wires were connected across, or as if the circuit were through to paris. their effect is precisely the same as though the capacity of the aerial section were reduced by a quantity, m, which is of the same dimension or character as k. hence, our retardance equation becomes r (k - m) = t [illustration: fig .] [illustration: fig .] thus it happens that the london-paris telephone works better than was expected. the nature of m is probably equivalent to about . [phi] per mile, and therefore k should be also about . [phi] instead of . [phi] per mile. this helpful action of mutual induction is present in all long circuits, and it is the reason why we were able to speak to brussels and even to marseilles. it also appears in every metallic loop, and vitiates the measurements of electromagnetic inertia and of capacity of loops. thus, if we measure the capacity of a loop as compared with a single wire, the amount per mile may be per cent. greater than it ought to be; while if we measure the capacity of one branch of a circuit under the conditions of the london-paris telephone line, it may be per cent. less than it ought to be. this effect of m is shown by the dotted line in fig. . telephonic currents--that is, currents induced in the secondary wire of an induction coil due to the variation of microphonic currents in the primary wire--are not alternating currents. they do not follow the constant periodic law, and they are not true harmonic sine functions of the time. the microphonic currents are intermittent or pulsatory, and always flow in the same direction. the secondary currents are also always of the same sign, as are the currents in a ruhmkorff coil, and as are the currents in high vacua with which crookes has made us so familiar. moreover, the frequency of these currents is a very variable quantity, not only due to the various tones of voices, but to the various styles of articulation. hence the laws of periodic alternate currents following the sine function of the time fail when we come to consider microphones and telephones. it is important to bear this in mind, for nearly everything that has hitherto been written on the subject assumes that telegraphic currents follow the periodic sine law. the currents derived from bell's original magneto-transmitters are alternate, and comply more nearly with the law. the difference between them and microphones is at once perceptible. muffling and disturbance due to the presence of electromagnetic inertia become evident, which are absent with microphones. i tested this between london and st. margaret's, and found the effect most marked. . _lightning._--a metallic telephone circuit may have a static charge induced upon it by a thunder cloud, as shown in fig. . such a charge is an electric strain which is released when the charged cloud flashes into the earth or into a neighboring cloud. if there be electromagnetic inertia present, the charge will surge backward and forward through the circuit until it dies out. if there be no e.m.f. present it will cease suddenly, and neutrality will be attained at once. telephone circuits indicate the operation by peculiar and characteristic sounds. an iron wire circuit produces a long swish or sigh, but a copper wire circuit like the paris-london telephone emits a short, sharp report, like the crack of a pistol, which is sometimes startling, and has created fear, but there is no danger or liability to shock. indeed, the start has more than once thrown the listener off his stool, and has led to the belief that he was knocked down by lightning. [illustration: fig .] . the future of telephone working, especially in large cities, is one of underground wires, and the way to get over the difficulties of this kind of work is perfectly clear. we must have metallic circuits, twisted wires, low resistance, and low capacity. in paris a remarkable cable, made by fortin-herman, gives an exceedingly low capacity--viz., only . [phi] per mile. in the united states they are using a wire insulated with paper which gives . [phi] per mile. we are using in london fowler-waring cable giving a capacity of . [phi] per mile, the capacity of gutta-covered wire being [phi] per mile. * * * * * the manufacture of phosphorus by electricity. one of the most interesting of the modern applications of electricity to the manufacture of chemicals is to be found in the recently perfected process known as the readman-parker process, after the inventors dr. j.b. readman, f.r.s.e., etc., of edinburgh, and mr. thomas parker; the well known practical electrician, of wolverhampton. before giving an account of this process, which has advanced beyond the experimental to the industrial stage, it may be well to recall the fact that for several years past dr. readman has been devoting an enormous expenditure of labor, time and money to the perfection of a process which shall cheapen the production of phosphorus by dispensing altogether with the use of sulphuric acid for decomposing the phosphate of lime which forms the raw material of the phosphorus manufacturer, and also with the employment of fire clay retorts for distilling the desiccated mixture of phosphoric acid and carbon which usually forms the second stage of the operation. the success of the recent applications of electricity in the production of certain metals and alloys led dr. readman to try this source of energy in the manufacture of phosphorus, and the results of the first series of experiments were so encouraging that he took out provisional protection on october , , for preparing this valuable substance by its means. the experiments were carried on at this time on a very small scale, the power at disposal being very limited in amount. yet the elements of success appeared to be so great, and the decomposition of the raw material was so complete, that the process was very soon prosecuted on the large scale. after a good deal of negotiation with several firms that were in a position to supply the electric energy required, dr. readman finally made arrangements with the directors of the cowles company, limited, of milton, near stoke-on-trent, the well known manufacturers of alloys of aluminum, for a lease of a portion of their works and for the use of the entire electrical energy they produced for certain portions of the day. the experiments on the large scale had not advanced very far before dr. readman became aware that another application for letters patent for producing phosphorus had been made by mr. thomas parker, of wolverhampton, and his chemist, mr. a.e. robinson. their joint patent is dated december , , and was thus applied for only seven weeks after dr. readman's application had been lodged. it appeared that mr. parker had conducted a number of experiments simultaneously but quite independently of those carried on by dr. readman, and that he was quite unaware--as the latter was unaware--of any other worker in this field. it was no small surprise, therefore, to find during an interview which took place between these rival inventors some time after the date referred to, that the two patents were on practically the same lines, namely, the production of phosphorus by electricity. their interests lay so much together that, after some delay, they arranged to jointly work out the process, and the result has been the formation of a preliminary company and the erection on a large scale of experimental plant in the neighborhood of wolverhampton to prove the commercial success of the new system of manufacturing phosphorus. before describing these experimental works it may be as well to see with what plant dr. readman has been working at the cowles company's works. and here we may remark that we are indebted to a paper read by dr. readman at the philosophical institution, edinburgh, a short time ago; this paper being the third of a series which during the last year or two have been read by the same scientist on this branch of chemical industry. here is an abstract giving a description of the plant. the works are near the milton station, on the north staffordshire railway. the boilers for generating the steam required are of the babcock-wilcox type, and are provided with "mechanical stokers;" the steam engine is of horse power, and is a compound condensing horizontal tandem, made by messrs. pollitt & wigzel, of sowerby bridge. the fly wheel of this engine is feet in diameter, and weighs tons, and is geared to the pulley of the dynamo, so that the latter makes five revolutions for each revolution of the engine by rope driving gear, consisting of eighteen ropes. the engine is an extremely fine specimen of a modern steam engine; it works so silently that a visitor standing with his back to the engine railings, at the time the engine is being started, cannot tell whether it is in motion or not. with regard to the dynamo, the spindle is of steel, feet long, with three bearings, one being placed on either side of the driving pulley. the diameter is inches in the bearings and inches in the part within the core. this part in the original forgings was inches in diameter, and was planed longitudinally, so as to leave four projecting ribs or radial bars on which the core disks are driven, each disk having four key ways corresponding to these ribs. there are about of these disks, the external diameter being inches and the total length of the core inches. the armature winding consists of copper bars, each / in. deep, measured radially, by / in. wide. these bars are coupled up so as to form thirty-two conductors only; this arrangement has been adopted to avoid the heating from the foucault currents, which, with ½ in. conductors, would have been very considerable. the bars are coupled at the ends of the core across a certain chord and are insulated. the commutator is inches long, and has sixty-four parts. the current is collected by eight brushes mounted on a separate ring, placed concentric to the commutator; and the current is led away from these brushes by a large number of thin bands of sheet copper strapped together into convenient groups. the field magnets are of the horizontal double type. as this machine is virtually a series wound machine, the magnet coils each consist of a few turns only of forged copper bars, ½ in. wide by in. thick, forged to fit the magnet cores. there is no insulation other than mica wedges to keep the bars from touching the core. the dynamo furnishes a current of about , amperes, with an e.m.f. of to volts, and three years ago was claimed to be the largest machine, at least as regards quantity of current, in the world. the current from the dynamos is led by copper bars to an enormous "cut out," calculated to fuse at , amperes. this is probably one of the largest ever designed, and consists of a framework carrying twelve lead plates, each ½ in. × / th in. thick. a current indicator is inserted in the circuit consisting of a solenoid of nine turns. the range of this indicator is such that the center circle of °= , amperes. the electrodes consisted of a bundle of nine carbons, each ½ in. in diameter, attached by casting into a head of cast iron. each carbon weighs lb, and, when new, is about inches long. the head of the electrode is screwed to the copper rods or "leads," which can be readily connected with the flexible cable supplying the current. the electric furnaces are rectangular troughs built of fire brick, their internal dimensions being in. × in. × in. deep. into each end is built a cast iron tube, through which the carbon electrodes enter the furnace. the electrodes are so arranged that it is possible by means of screwing to advance or withdraw them from the furnace. the whole current generated by the great dynamo of the cowles company was passed through the furnace. in the experiments raw materials only were used, for it was evident that it was only by the direct production of phosphorus from the native minerals which contain it, such as the phosphates of lime, magnesia, or alumina that there was any hope of superseding, in point of economy, the existing process of manufacture. in the furnaces as used at milton much difficulty was experienced in distributing the heat over a sufficiently wide area. so locally intense indeed was the heat within a certain zone, that all the oxygen contained in the mixture was expelled and alloys of iron, aluminum, and calcium combined with more or less silicon, and phosphorus were produced. some of these were of an extremely interesting nature. we now turn to a short account of the works and plant which have been erected near wolverhampton to prove the commercial success of the new system of manufacturing phosphorus. the ground is situated on the banks of a canal and extends to about acres, which are wholly without buildings except those which have been erected for the purposes of these industrial experiments. these consist of boiler and engine houses, and large furnace sheds. there are three babcock & wilcox steam boilers of horse power each, and each capable of evaporating , lb. of water per hour. the water tubes are ft. long × inches diameter, and the steam and water drums in. in diameter and ½ ft. long, of steel / ths. in. thick, provided with a double dead head safety valve, stop valves, blow-off cock, water gauges, and steam gauge. the total heating surface on each boiler is , square feet and the total grate surface is square feet. the boilers are worked at lb. pressure. the engine is a triple compound one of the type supplied for torpedo boats, and built by the yarrow shipbuilding company. it is fitted with a pickering governor for constant speed. the engine is capable of delivering (with condenser) , indicated horse power, and without condenser indicated horse power less. with steam at lb. pressure the engine worked at revolutions per minute, but it has been rearranged so as to deliver indicated horse power with lb. steam pressure without condenser, and at revolutions per minute: the high pressure cylinder is ½ inches diameter. " intermediate " " " " " low pressure " " " " " stroke is inches. the dynamo for producing the requisite amount of electric current supplied to the furnaces is one of the well known elwell-parker type of alternating current dynamos, designed to give units of electrical energy, equivalent to indicated horse power. the armature in the machine is stationary, with double insulation between the armature coils and the core, and also between the core and the frame, and is so arranged that its two halves may be readily connected in series or in parallel in accordance with the requirements of the furnaces, e.g., at an electromotive force of volts it will give , amperes, and at volts, , amperes when running at revolutions per minute. the exciting current of the alternator is produced by an elwell-parker shunt wound machine, driven direct from a pulley on the alternator shaft, and so arranged as to give amperes at volts when running at a speed of revolutions per minute. from to amperes are utilized in the alternator, the remainder being available for lighting purposes (which is done through accumulators) and general experimental purposes. the process is carried out in the following way: the raw materials, all intimately and carefully mixed together, are introduced into the furnace and the current is then turned on. shortly afterward, indications of phosphorus make their appearance. the vapors and gases from the furnace pass away to large copper condensers--the first of which contains hot and the second cold water--and finally pass away into the air. as the phosphorus forms, it distills off from the mixture, and the residue forms a liquid slag at the bottom of the furnace. fresh phosphorus yielding material is then introduced at the top. in this way the operation is a continuous one, and may be continued for days without intermission. the charges for the furnace are made up with raw material, i.e., native phosphates without any previous chemical treatment, and the only manufactured material necessary--if such it may be called--is the carbon to effect the reduction of the ores. the crude phosphorus obtained in the condensers is tolerably pure, and is readily refined in the usual way. dr. readman and mr. parker have found that it is more advantageous to use a series of furnaces instead of sending the entire current through one furnace. these furnaces will each yield about ½ cwt. of phosphorus per day. analyses of the slag show that the decomposition of the raw phosphates is very perfect, for the percentage of phosphorus left in the slag seldom exceeds per cent.--_chemical trade journal_. * * * * * new bleaching apparatus. the apparatus forming the subject of this invention was designed by francis a. cloudman, erwin b. newcomb, and frank h. cloudman, of cumberland mills, me., and comprises a series of tanks or chests, two or more in number, through which the material to be bleached is caused to pass, being transferred from one to the next of the series in order, while the bleaching agent is caused to pass through the series of chests in the reverse order, and thus acts first and at full strength upon the materials which have previously passed through all but the last one of the series of chests and have already been subjected to the bleaching agent of less strength. for convenience, the chest in which the material is first introduced will be called the "first of the series" and the rest numbered in the order in which the material is passed from one to the other, and it will be understood that any desired number may be used, two, however, being sufficient to carry on the process. the invention is shown embodied in an apparatus properly constructed for treating pulp used for the manufacture of paper, and for convenience the material to be bleached will be hereinafter referred to as the pulp, although it is obvious that similar apparatus might be used for bleaching other materials, although the apparatus might have to be modified to adapt it for conveying other materials of different nature than pulp from one bleaching chest to the other and for separating out the bleaching liquid and conveying it from one chest to the other in the reverse order to that in which the material passes from one chest to the next. the pulp material with which the apparatus herein illustrated is intended to be used is retained in suspension in the bleaching liquid and flows readily through ducts or passages provided for it in the apparatus in which the pulp to be bleached and the bleaching liquid are introduced together at the bottom of each chest and flow upward therethrough, while at the top of each chest there are two conveyors, one for carrying the pulp from one chest to the next in order, while the other carries the bleaching liquid from one tank to the next in the reverse order, the said conveyors also acting to partially separate the pulp from the liquid in which it has been suspended during its upward passage through the chest. suitable agitators may be employed for thoroughly mixing the materials in the chest and in the apparatus shown the bleaching agent and material to be bleached pass through each chest in the same direction--namely from the bottom to the top--although they are carried from one chest to the next in the reverse order, the material to be bleached being primarily introduced into the chest at one end of the series, while the bleaching agent or solution is introduced primarily into the chest at the other end of the series. fig. is a plan view of an apparatus for bleaching in accordance with this invention, comprising a series of four chests, and fig. is a vertical longitudinal section of a modified arrangement of two chests in line with one another, and with the conveyor for the material to be bleached and the passage through which said material passes from the top of one chest into the bottom of the next chest in the plane of section. [illustration: fig. ] the chests, _a_ _a _ _a _ _a _, may be of any desired shape and dimensions and any desired number may be used. each of said chests is provided with an inlet passage, _b_, opening into the same near its bottom, and through this passage the materials are introduced. the unbleached material, which may be paper pulp or material which is readily held in suspension in a liquid and is capable of flowing or being conveyed from one point to another in a semi-fluid condition, is introduced through the inlet passage, _b_, to the first chest, _a_, of the series, said pulp preferably having had as much as possible of the liquid in which it was previously suspended removed without, however, drying it, and, together with the said pulp, the bleaching agent which has previously passed through the other chests of the series, as will be hereinafter described, is introduced so that both enter together at the lower portion of the first chest, _a_, of the series. the said materials are caused to flow into the chest continuously, so that the portion at each moment entering tends to displace that which has already entered, thus causing the materials to rise gradually or flow upward from the bottom to the top of the chest. suitable stirring devices or agitators, _c_, may be employed to keep the pulp in suspension and to expose it thoroughly and uniformly to the liquid introduced with it. [illustration: fig. ] when the materials (the pulp and the bleaching liquid) arrive at or near the top of the chest, they are partially separated from one another and removed from the chest at substantially the same rate that they are introduced, as follows: each chest is provided at its upper part with a liquid conveyor, _d_, having a construction similar to that of the device known as a "washer" in paper making machinery, consisting of a rotating drum, the periphery of which is covered with gauze, which permits the liquid to pass into it, but excludes the pulp suspended in the liquid, the said drum containing blades or buckets that raise the liquid which thus enters through the gauze and discharges it at _d _ near the axis of said drum. there is one of these washers in each one of the series of chests, and each discharges the liquid taken from its corresponding chest into the inlet pipe of the next preceding chest of the series, the washer in the chest, _a _, for example, delivering into the inlet passage, _b_, of the chest, _a _, and so on, while the washer of the first chest, _a_, of the series delivers into a discharge pipe, _e_, through which the liquid may be permitted to run to waste or conveyed to any suitable receptacle, if it is desired to subject it to chemical action for the purpose of renewing its bleaching powers or obtaining the chemical agents that may be contained within it. the operation of the washers in removing the liquid from the upper part of the chest tends to thicken the pulp therein, and the said thickened pulp is conveyed from one chest to the next in the series by any suitable conveying device, _f_ (shown in this instance as a worm working in a trough or case, _f _), which may be made foraminous for the purpose of permitting the liquid to drain out of the pulp that is being carried through by the worm, in order that the pulp may be introduced into the next chest of the series as free as possible from the liquid in which it has been suspended while in the chest from which it is just taken. the pulp is thus conveyed from one chest in the series to the inlet passage leading to the next chest of the series, and in the said inlet passage it meets the liquid coming in the reverse order from the next chest beyond in the series, the pulp and liquid thus commingling in the inlet pipe and entering the chest together, and being thoroughly mixed by the agitators in passing through the chest by the continued action of fresh material entering and of the conveyors taking the material out from the chests. in the last of the series of chests into which the pulp is introduced the fresh or strong bleaching liquid is introduced through a suitable inlet pipe, _g_, and the pulp conveyor, _f_, that takes the pulp from the last chest, delivers it into a pipe, _h_, by which it may be conveyed to any desired point, the said pulp having been sufficiently bleached before arriving at the said pipe, _h_. it will be seen that by these means all the pulp is thoroughly and uniformly subjected to the bleaching agent and that the bleaching is gradually performed in all parts of the pulp, which is first acted upon by the weaker bleaching agent that has previously operated upon the pulp before treated, and that finally, when nearly bleached, the pulp is acted upon by the bleaching material of full strength, this action being far more efficient than when the materials are simply mixed together, the unbleached material with the strong bleaching agent, and allowed to remain together until the bleaching operation is finished, in which plan the bleaching agent loses its strength as the bleaching operation approaches completion, so that when the pulp is nearly bleached it is operated upon by a very weak bleaching agent. by having the pulp transferred from one chest to the next in the reverse order to that in which the liquid is transferred it will be seen that all parts of the pulp are acted upon uniformly and equally and that the operation may go on continuously for an indefinite period of time without necessitating stopping to empty the vats, as is the case when the liquor only is transferred from one vat to the next. a pump may be used for lifting the bleaching liquid, as shown, for example, at _k_, fig. . where said pump is used to raise the liquid delivered from the chest, _a _, and discharge it into the trough, _m_, by which the pulp is carried to the inlet pipe, _b_. by the use of the pump, _h_, a stronger flow of the liquid into the pipe _b_, of the first chest, _a_, is effected than if it were taken directly from the washer of the chest, _a _, which is desirable, as the pulp is delivered in the trough, _m_, with but little moisture. it is obvious that the construction of the apparatus may be varied considerably without materially changing the essential features of operation. for example, the washers might be dispensed with and the liquid permitted to flow through suitable strainers from one chest to the next in order, by gravity, the successive chests in the order of the passage of the pulp being placed each at a higher level than the preceding one, and it is also obvious that the construction of the pulp conveyors might be widely varied, it being essential only that means should be provided for removing the pulp from one chest and delivering it into the next while carrying only a small amount of the liquid from one chest to the next with the pulp. * * * * * the use of compressed air in conjunction with medicinal solutions in the treatment of nervous and mental affections. being a new system of cerebro-spinal therapeutics. by j. leonard corning, a.m., m.d., new york, consultant in nervous diseases to st. francis hospital, st. mary's hospital, the hackensack hospital, etc. to merely facilitate the introduction of medicinal agents into the system by way of the air passages, in the form of gases, medicated or non-medicated, has heretofore constituted the principal motive among physicians for invoking the aid of compressed air. the experiments of paul bert with nitrous oxide and oxygen gas, performed over fourteen years ago, and the more recent proposals of see, are illustrations in point. the objects of which i have been in search are quite different from the foregoing, and have reference not to the introduction of the remedy, but to the enhancement of its effects after exhibition. let me be more explicit on this point, by stating at once that, in contradistinction to my predecessors, i shall endeavor to show that by far the most useful service derivable from compressed air is found in its ability to enhance and perpetuate the effects of soluble remedies (introduced hypodermically, by the mouth, or otherwise) upon the internal organs, and more especially upon the cerebro-spinal axis. some chemical affinity between the remedy employed and the protoplasm of the nerve cell is, of course, assumed to exist; and it is with the enhancement of this affinity--this bond of union between the medicinal solution and the nervous element--that we shall chiefly concern ourselves in the following discussion. by way of introduction, i may recall the fact that my attention was directed several years since to the advisability of devising some means by the aid of which medicinal substances, and more especially anæsthetics, might be made to localize, intensify, and perpetuate their action upon the peripheral nerves. the simple problem in physiology and mechanics involved in this question i was fortunate enough to solve quite a long time ago; and i must confess that in the retrospect these undertakings in themselves do not seem to me of great magnitude, though in their practical application their significance appears more considerable. herein lies, it may be, the explanation of the interest which these studies excited in the profession at the time of their publication. these things are, however, a part of medical history; and i merely refer to them at this time because they have led me to resume the solution of a far greater problem--that of intensifying, perpetuating, and (to some extent at least) localizing the effects of remedies upon the brain and spinal cord. i speak of resuming these studies because, as far back as and , i made some attempts--albeit rather abortive--in the same direction. in constructing the argument for the following study, i am beholden more especially to three facts, the knowledge of which came to me as the direct result of experimental tests. one may place confidence, therefore, in the procedure which i have based upon these premises, for at no point, i think, in the following argument will mere affirmation be found to have usurped the place of sound induction. without anticipating further, then, let me specify as briefly as may be the nature of these facts. premises of argument. _first fact._--the amount of ether, chloroform, chloral hydrate, the bromides, strychnine, and many other remedies, required to produce physiological effects upon the cerebro-spinal mechanism may be reduced by first securing a ligature around the central portion of one or several of the limbs of an animal, so as to interrupt both the arterial and venous circulation. the proof and explanation of this may be thus presented: in the first place, it is well known that children and small animals are affected by much smaller quantities of anæsthetics and other medicinal substances than are required to produce equal effects in men and large animals. at first sight, there appears to exist a certain definite relation between the weight of the animal and the quantity of medicament required to produce physiological effects. on closer inquiry, however, we find behind this proposition the deeper truth that the real proportion is between the magnitude of the blood-mass and the amount of medicament. thus, if we withdraw a considerable amount of blood from a large dog, we may be able to affect him by much smaller doses than those required under ordinary circumstances; and, among human beings, we find the anæmic much more susceptible to remedies than the full-blooded of equal weight. the degree of saturation of the blood-mass with the remedy is obviously, then, the principal thing; the greater the amount of blood, the more remedy--everything else being equal--we shall have to give in order to obtain definite results. if we wish to embody the proposition in a mathematical statement, we may do so in the following simple manner: let a represent the total quantity of blood, _b_, the amount of remedy exhibited, and _x_ the magnitude of the physiological effect. we shall then have the simple formula, x = b / a. again, if we withdraw a certain quantity of blood from the circulation by venesection, and call that amount _d_, we shall then have the formula x = b / (a-d). but, if we wish to act upon the organs of the trunk, and more especially upon those contained within the cerebro-spinal canal, it is not necessary to resort to such a drastic expedient as copious blood-letting; for, in place of this, we may dam up and effectually eliminate from the rest of the body a certain amount of blood by passing a ligature around the central portion of one or several extremities, so as to interrupt the circulation in both artery and vein. when this has been done it is clear that we may introduce a remedy into the system by way of the stomach, or hypodermically into some portion of the trunk; and it is equally certain that a remedy so introduced will be diluted only in the ratio of the amount of blood freely circulating, and more especially by that contained within the trunk and head. that which is incarcerated behind the ligatures is as effectually withdrawn from the realm of physiological action as though it had been abstracted by the surgeon's knife. elimination by the knife and elimination by the ligature are, for present purposes, then, one and the same thing. hence, if we let _d'_ represent the amount of blood incarcerated behind the ligatures, _x_ the magnitude of the physiological effect which we are seeking, _b_ the amount of remedy exhibited, and a the total amount of blood contained in the whole organism, we shall have the formula, b b x = ------ = ----- a - d' a - d several years since, i had an excellent opportunity of proving the truth of the foregoing, in connection with the administration of ether in the case of a patient who resisted all attempts to anæsthetize him in the ordinary way. the case in question was a man under treatment at the manhattan eye and ear hospital, upon whom it was deemed advisable to perform an operation. as has been said, the ordinary means of inducing anæsthesia had proved ineffectual, for the man was a confirmed drunkard; and it was at this juncture that i was called in consultation and requested by my friend, dr. david webster, one of the surgeons of the hospital, to endeavor to devise some means of getting the man under the influence of the anæsthetic. the procedure which i suggested was this:[ ] around the upper part of each thigh a flat rubber tourniquet was tightly drawn and secured in place in the usual manner. by this means the sequestration of all the blood contained in the lower limbs was accomplished; but, inasmuch as both artery and vein were compressed, only the amount of blood usually contained in each limb was shut off from the rest of the body--which would not have been the case had we contented ourselves with merely compressing the veins, as some have done. [footnote : on the "effective and rapid induction of general anæsthesia," the new york _medical journal_, october and december , .] in subsequently commenting on my published report of this case, that most accomplished writer and physician, henry m. lyman--than whom there is no greater authority on anæsthesia--observes that the plan proposed and adopted by me on this occasion (that of compressing both vein and artery) is far preferable to compression of the vein alone. the reason for this is not far to seek. when we compress the veins alone there is a rapid accumulation of blood in the extremities through the accessions derived from the uninterrupted arteries. now, as this blood is derived from the trunk, and consequently also from the organs contained within the cerebro-spinal canal, there is danger of syncope and even heart failure. when, on the other hand, both artery and vein are compressed no such derivative action occurs, and all danger is, consequently, removed. with an apology for this brief digression, i now return to the interesting case which has given rise to it. having, as previously stated, applied tourniquets to the central portion of the lower limbs, the ether cap was placed over the mouth and nose of the patient, and in an incredibly short time he was unconscious, and the surgeons were able to go on with the operation. the late dr. cornelius r. agnew and many other members of the staff of the hospital were present, and gave emphatic expressions of approval. dr. f.w. ring, assistant surgeon to the manhattan eye and ear hospital, declared that both the amount of ether and the time consumed in its administration were infinitesimal when compared with what had been expended in previous efforts at inducing anæsthesia in the usual way. the facts brought out on this occasion with regard to the administration of ether have since been repeatedly verified by different observers; so that at the present day their validity cannot be questioned. i will merely add, however, that i have long known that the dosage of phenacetin, antipyrine, morphine, chloralamid, chloral, the bromides, and many other remedies might be reduced by resort to the same procedure; all of which is merely equivalent to stating that their pharmaco-dynamic energy may be increased in this way. and this brings us to the second fact, which requires no special elaboration, and may be stated thus: _second fact._--the duration of the effect of a remedy upon the cerebro-spinal axis is in the inverse ratio of its volatility; and this is equally true whether the remedy be given with or without the precautions previously detailed. for example, the anæsthetic effects of ether disappear shortly after removal of the inhaler, whether we apply tourniquets to the extremities or not; but, on the other hand, the analgesic influence of antipyrin, phenacetin, morphine, and other like remedies lasts very much longer, and their dose may be reduced, or--what is the same thing--their pharmaco-dynamic potency may be enhanced by the sequestration of the blood contained within the extremities. so far as i know, i was the first to announce this fact. in so far as a simple expression of the above truth is concerned, we may employ the following formula: let _a_ represent the normal blood-mass contained in the entire body, _d_ the amount of blood sequestrated by the ligatures, _b_ the amount of the remedy, _c_ the volatility of the remedy, and _x_ the pharmaco-dynamic potency of which we are in search; we shall then have b x = ----------- (a - d') × c we now arrive at our third fact, which will require more extensive elaboration. _third fact._--the pharmaco-dynamic potency of stimulants, sedatives, analgesics, and probably of all remedies which possess a chemical affinity for nervous matter, is enhanced by exhibiting them (the remedies) in solution or soluble form--hypodermically, by the mouth, or per rectum--while the subject remains in a condensed atmosphere. and, as a corollary, it may be stated that this increase, this enhancement of the potency of the remedy is, within certain limits, in the ratio of the atmospheric condensation. to express this truth mathematically is not difficult. thus, when a represents the amount of blood of the whole body, _b_ the amount of the remedy, _e_ the amount of atmospheric compression, and _x_ the pharmaco-dynamic potentiality which we are seeking, we shall then have the simple formula: b x e x = ----- a a definite conception of the truth of this proposition will, i think, be more readily attained by the presentation of the steps which led me to its discovery. let me begin, then, by stating that my attention was attracted several years ago by that unique complex of symptoms known as the "caisson or tunnel disease." as most physicians are aware, the caisson disease is an affection of the spinal cord, due to a sudden transition from a relatively high atmospheric pressure to one much lower. hence, those who work in caissons, or submerged tunnels, under an external pressure of two atmospheres or even more, are liable to be attacked by the disease shortly after leaving the tunnel. the seizure never, however, occurs while the subject is in the caisson, or in other words, while he remains under pressure. moreover, when the transition from the condensed atmosphere to that of ordinary density is gradually accomplished, which may be done by letting the air escape from the lock very slowly, the caisson disease is rarely if ever set up. it is the systematic disregard of this principle by those who work in compressed air that is responsible, or largely responsible, for the occurrence of the disease. the chief clinical features of the caisson disease are pain, which may be relatively mild, as when confined to a circumscribed area of one extremity, or of frightful intensity, as when it appears in the ears, knees, back, or abdomen; anæsthesia and paralysis, usually of paraplegic type; bladder symptoms, assuming the form of retention or incontinence; and, more rarely, rectal disturbances (usually incontinence). these phenomena, or rather some of them, appear some time within half an hour after the subject has left the compressed atmosphere. it was while investigating this most interesting affection as it occurred in the course of the construction of the hudson river tunnel, that i was able, at the same time, to study the effects of compressed air upon the organism, and especially upon the nervous system, as exhibited in a large number of persons. the results of these studies i now submit without hesitation, and in all candor, to the judgment of the profession, believing, as i certainly do, that their practical significance from a neuro-therapeutic standpoint is assured. without anticipating, however, let me state that the first thing which impressed me about compressed air was its extraordinary effect upon cerebral and cerebro-spinal function. those who remain for a certain length of time, not too long, however, in the condensed atmosphere, exhibit a most striking exacerbation of mental and physical vigor. they go up and down ladders, lift heavy weights, are more or less exhilarated, and, in short, behave as though under the influence of a stimulant. hardly had i observed these things, which are perfectly well known to those who have been able to familiarize themselves with the ordinary effects of compressed air as used in caissons and submarine works of various kinds, when my attention became attracted by what at first appeared to be a phenomenon of trivial importance. in a word, i observed that some of the men exposed to the effects of the compressed air were more exhilarated by it than others. upon superficial reflection one might have supposed that this discrepancy in physiological effect was to be accounted for merely on the basis of constitutional idiosyncrasy; maturer thought, however, convinced me that the exaggerated effects of the condensed air were both too numerous and too constant to be amenable to such an explanation. this led me to study the habits of the men; and thus it was that i arrived at a discovery of real practical value to neurotherapy. to be brief, i found that a certain percentage of the men, before entering the compressed air employed in the construction of the hudson river tunnel, were in the habit of drinking a quantity of alcohol, usually in the form of whisky. so long as these men remained outside the tunnel, where the atmospheric conditions were normal, they were not visibly affected by their potations. when, however, they entered the compressed air of the tunnel, but a short time elapsed before they became exhilarated to an inordinate degree, acting, as one of the foremen graphically expressed it, "as though they owned the town." on the other hand, when the customary draught of alcohol was withheld from them, these same men were no more, if as much, exhilarated on entering the compressed air as were their fellows. the effects of alcohol, then, are enhanced by exposing the subject to the influence of an atmosphere condensed to a considerable degree beyond that of the normal atmosphere. acting on the hint derived from this discovery, i proceeded to administer absinthe, ether, the wine of coca, vermouth, champagne, and other stimulants, before exposing the subject to the influence of the condensed atmosphere, and invariably observed analogous effects, i.e., palpable augmentation of the physiological effects of the remedy. upon what principle does this augmentation of physiological effect depend? how is it to be accounted for? in my opinion, the answer to this question may be given as follows: in the first place, we know that the primary effect of the compressed air upon the organism must be to force the blood from the surface of the body toward the interior, and especially into the cerebro-spinal canal. or, to express it more succinctly, the blood will be forced in the direction of the least resistance, that is, into the soft organs inclosed by bony walls, which latter completely shut out the element of counter-pressure. now, when the blood stream is freighted with a soluble chemical of some sort--let us say, for the present, with alcohol--this medicated blood will exert its greatest chemical effect where the tension--the pressure--is greatest, that is, in the cerebro-spinal canal. the reason for this is found in the fact that endosmosis is most pronounced where the blood pressure is greatest. this explanation of why the effects of alcohol are enhanced by exposing the individual who has taken it to the effects of a condensed atmosphere will, i believe, appeal to the physiological conceptions of most medical men. it was the above course of reasoning which, at this stage of the argument, led me to the idea that, just as the effects of stimulating substances are enhanced by exposing the subject to the influence of compressed air, so, inversely, sedatives and analgesics, when brought in solution into the blood stream, either hypodermically or by the stomach, might be greatly enhanced in effect by causing the subject to remain, while under their influence, in a condensed atmosphere. when i came to investigate the validity of these predictions, as i did shortly after the introduction of antipyrin, phenacetin, and the other members of the same group of compounds, i found my predictions verified, and, indeed, exceeded. to summarize the whole matter, i ascertained that not only could therapeutic effects be obtained from much smaller doses by exposing the subject to the influence of a condensed atmosphere, but, what was of equal interest, i found that the analgesic influence of the remedies was much more permanent, was prolonged, in short, by this mode of administration. when we consider how great must be the nutritive changes in the nervous system, and especially in the cerebro-spinal axis, consequent upon increasing the blood pressure in this way, i hardly think that these things should be matters of astonishment. concerning the practical application of the foregoing facts.--truths like the foregoing possess, however, much more than a theoretical interest, and we should be greatly lacking in perspicuity did we not seek to derive from them something further than a foundation for mere speculation. indeed, the whole tenor of these facts is opposed to such a course, for, view them as we may, the thought inevitably arises that here are things which contain the germ of some practical acquisition. this, at least, is the impression which they engendered in my own mind--an impression which, being unable to rid myself of, i have allowed to fructify. nor has regret followed this tenacity of purpose, since, by the _combination_ of the three principles previously enunciated, i have been able to devise a procedure which, in my hands, has yielded flattering results in the treatment of a wide range of nervous affections, and notably so in melancholia, chorea, insomnia, neurasthenia, and painful conditions of various kinds. recapitulation of argument.--the method in question consists, then, in the combination of the three facts already elucidated. to recapitulate, they are: . that the effects of remedies upon the cerebro-spinal axis may be enhanced by the sequestration of the blood contained in one or more extremities, previous to the administration of the medicament. this is only another way of saying that the quantity of a remedy required to produce a given physiological effect may be reduced by any expedient which suspends, or sequestrates, the blood in one or more extremities. as has been previously said, however, care should be exercised to avoid dangerous exsanguination of the trunk, and consequently of the respiratory and cardiac centers contained in the medulla. this may be done by compressing the central portion of both artery and vein; but i shall presently indicate a better way of accomplishing the same thing. . the duration of the effect of a remedy upon the cerebro-spinal axis is in the inverse ratio of its volatility. for this reason the anæsthetic effects of ether disappear shortly after removal of the inhaler, whereas solutions of antipyrin, phenacetin, morphine, and other salts possessing an affinity for nervous tissue exert much more permanent effects upon the cerebro-spinal system. it is evident, therefore, that the administration of remedies designed to exert an influence upon the central nervous system in the form of gases must be far inferior to the exhibition of potent solutions hypodermically or by the mouth. . the pharmaco-dynamic potency of stimulants, sedatives, analgesics, and probably of all remedies possessing a chemical affinity for nervous matter, is enhanced by exhibiting them (the remedies) in solution, or at least in _soluble form while the subject remains in a condensed atmosphere_. and, as a corollary to this, it may be stated that this increase--this enhancement of therapeutic effect--is, within physiological limits, in the ratio of the atmospheric condensation. by physiological limits we mean simply that there is a degree of atmospheric condensation beyond which we cannot go without jeopardizing the well-being of the subject. (_to be continued_.) * * * * * eyesight: its care during infancy and youth.[ ] [footnote : a lecture delivered before the franklin institute, december , .--_from the journal of the institute_.] by l. webster fox, m.d. medical science, as taught in our medical colleges to-day, has two objects in view: ( ) the prevention of disease; ( ) the amelioration of disease and its cure. some of our advanced thinkers are suggesting a new mode of practice, that is the prevention of disease by proper hygienic measures. chairs are being established and professors appointed to deliver lectures on hygiene. of what value is the application of therapeutics if the human economy is so lowered in its vital forces that dissolution is inevitable? is it not better to prevent disease than to try the cure after it has become established, or has honeycombed the constitution? these few preliminary remarks are _apropos_ to what is to follow in the subject which i have selected as the topic for discussion this evening. vision is the most useful of all the senses. it is the one gift which we should cherish and guard the most. and at no time in one's life is it more precious than in infancy and youth. in infancy, when the child is developing, the one great avenue to the unfolding, or more properly speaking, the development, of the intellect is through the eye. the eye at this period holds in abeyance all the other senses. the child, when insensible to touch, taste, smell or hearing, will become aroused to action by a bright light or bright colors, or the movement of any illuminated object, proving to all that light is essential to the development of the first and most important sense. again, the infant of but six days of age will recognize a candle flame, while its second sense and second in importance to its development--hearing--will not be recognized for _six_ weeks to two months. taste, touch and smell follow in regular sequence. inasmuch as light makes thus early an impression on the delicate organ of vision, how necessary it behooves us to guard the infant from too bright lights or too much exposure in our bright climate. mothers--not only the young mother with her first child, but also those who have had several children--are too apt to try to quiet a restless child by placing it near a bright flame; much evil to the future use of those eyes is the outgrowth of such a pernicious habit. light throws into action certain cells of that wonderful structure of the eye, the retina, and an over stimulus perverts the action of those cells. the result is that by this over-stimulation the seeds of future trouble are sown. let the adult gaze upon the arc of an electric light or into the sun, and for many moments, nay hours, that individual has dancing before his vision scintillations and phosphenes. his direct vision becomes blurred, and as in the case of a certain individual i have in mind, there may be a permanent loss of sight. parents should take the first precaution in the child's life, and not expose it to a light too bright or glaring. when in the open air let the child's eyes be protected from the direct rays of the sun. while it is impossible to give all children the advantage of green fields and outdoor ramblings, yet nature never intended that civilization should debar the innocent child from such surroundings. an anecdote is related of a french ophthalmic surgeon, that a distinguished patient applied to him for relief from a visual defect; the surgeon advised him to go into the country and look out upon the green fields. the green color with its soothing effect soon brought about a restoration of vision. what i wish to illustrate by this anecdote is that children should be allowed the green fields as their best friend in early life. it tones up the system and rests the eye. after outdoor exercise and plenty of it, we should turn our attention to the home surroundings of our little ones. the overheated rooms of the average american home i am sure have more to do with the growing tendency of weak eyes than we feel like admitting. look at these frail hot-house plants, and can any one believe that such bodies nourished in almost pestilential atmosphere can nourish such delicate organs of vision, and keep them ready for the enormous amount of work each little eye performs daily? the brain developing so rapidly wills with an increasing rapidity the eye to do increasing duties; note the result--a tendency to impoverished circulation first, and the eye with its power to give the brain a new picture in an infinitesimal short space of time means lightning-like circulation--the eye must give way by its own exhaustion. civilization is the progenitor of many eye diseases. after a boy has grown to that age when it becomes necessary for him to begin the education prescribed by the wise men, obstacles are placed in his way to aid again in causing deterioration of vision. it is not so much the overcrowded condition of our school rooms as the enormous amount of work that causes deterioration of sight. our children begin their school life at a time when they are too young. a child at six years of age who is forced to study all day or even a part of a day will not run the same race that one will who commences his studies at ten--all things being equal. the law prescribes that so much time must be devoted to study, so many forms must be passed, so many books must be read, so many pages of composition written--all probably in badly lighted rooms, or by artificial light. note the effect. first, possibly, distant vision gives way; the teacher, sympathizing with the overburdened child, tries to make the burden lighter by changing his position in the room or placing him under the cross light from a window; as the evil progresses, the child is taken to an ophthalmic surgeon, and the inevitable result, glasses, rightly called "crutches for the eyes," are given. what would be thought of a cause which would weaken the legs of that boy so that he would have to use crutches to carry him through life? if civilization be responsible for an evil, let our efforts be put forth in finding a remedy for that evil. a discussion, in a recent number of the _british medical journal_,[ ] on "the claims and limitations of physical education in schools," has many valuable hints which should be followed by educators in this country. dr. carter, in the leading paper on this subject, makes the pregnant remark: "if the hope is entertained of building up a science of education, the medical profession must combine with the profession of teaching, in order to direct investigation and to collect material essential to generalization. without such co-operation educational workers must continue to flounder in the morasses of empiricism, and be content to purchase relative safety at the cost of slow progress, or no progress at all." in other words, an advisory medical board should coexist with our board of public education, to try to hold in check or prevent a further "cruelty in trying to be kind." private institutions of education recognize the importance of physical training and development, and in such institutions the deterioration of vision is in proportion less than in institutions where physical training is not considered. in one school of over middle class girls, dr. carter found that, during a period of six years, no fewer than ten per cent. of the total number of girls admitted during that time have been compelled to take one or more terms' leave of absence, and of the present number twenty-eight per cent. have medical certificates exempting them from gymnastic exercise and . per cent. of the total present number wear eye glasses of some kind or other. from my own experience the same number of students in our schools would show about the same percentage of visual defects. these questions are of such growing importance that not only instructors, but the medical fraternity, should not rest until these evils are eradicated. [footnote : nov. , .] dr. j.w. ballantyne, of edinburgh, in a lecture[ ] on diseases of infancy and childhood, says: "the education of the young people of a nation is to that nation a subject of vital importance." the same writer quotes the startling statement made by prof. pfluger, that of , children examined in germany more than one-half were suffering from defective eyesight, while in some schools the proportion of the short sighted was seventy or eighty per cent., and, crowning all, was the heidelberg gymnasium, with per cent. these figures, the result of a careful examination, are simply startling, and almost make one feel that it were better to return to the old greek method of teaching by word of mouth. [footnote : _lancet_. nov. , .] prof. pfluger attributes this large amount of bad sight to insufficient lighting of school rooms, badly printed books, etc. one must agree with a certain writer, who says: "schools are absolute manufactories of the short sighted, a variety of the human race which has been created within historic time, and which has enormously increased in number during the present century." granting that many predisposing causes of defective vision cannot be eliminated from the rules laid down by our city fathers in acquiring an education, it would be well if the architects of school buildings would bear in mind that light when admitted into class rooms should not fall directly into the faces of children, but desks should be so arranged that the light must be sufficiently strong and fall upon the desk from the left hand side. my attention has repeatedly been called to the cross lights in a school room. the light falling directly into the eyes contracts the pupil which is already contracted by the action of the muscle of accommodation in its effort to give a clearer picture to the brain. this has a tendency to elongate the eyeball, and as a permanent result we have near sightedness. where the eyeball has an unnatural shortness this same action manifests itself by headaches, chorea, nausea, dyspepsia, and ultimately a prematurely breaking down of health. the first symptom of failing sight is a hyper-secretion of tears, burning of the eyelids, loss of eyelashes, and congestion either of the eyelids or the eyeball proper. the natural condition of aboriginal man is far sighted. his wild life, his nomadic nature, his seeking for game, his watching for enemies, his abstention from continued near work, have given him this protection. humboldt speaks of the wonderful distant vision of the south american indians; another traveler in russia of the power of vision one of his guides possessed, who could see the rings of saturn. my recent examinations among indian children of both sexes also confirm this. while the comparison is not quite admissible, yet the recent investigations carried on by lang and barrett, who examined the eyes of certain mammalia, found that the larger number were hypermetropic or far sighted. with all the difficulties which naturally surround such an examination they found that in fifty-two eyes of rabbits, thirty-six were hypermetropic and astigmatic, eight were hypermetropic only, five were myopic and astigmatic, and others presented mixed astigmatism. in the eyes of the guinea pig about the same proportion of hypermetropia existed. the eyes of five rats examined gave the following result: some were far sighted, others were hypermetropic and astigmatic, one was slightly myopic and one had mixed astigmatism. of six cows, five were hypermetropic and astigmatic and one was slightly myopic. six horses were also examined, of which one had normal sight, three were hypermetropic and astigmatic, and two had a slight degree of astigmatism. they also examined other animals, and the same proportion of hypermetropia existed. these gentlemen found that as an optical instrument the eye of the horse, cow, cat and rabbit is superior to that of the rat, mouse and guinea pig. i have for the last five years devoted considerable attention to the vision of the indian children who are pupils at two institutions in this city. i have at various times made careful records of each individual pupil and have from time to time compared them. up to the present there is a growing tendency toward myopia or short sightedness, i.e., more pupils from year to year require near sighted glasses. the natural condition of their eyes is far sighted and the demands upon them are producing many nervous or reflex symptoms, pain over the frontal region and headaches. a good illustration of the latter trouble is showing itself in a young indian boy, who is at present undergoing an examination of his vision as a probable cause for his headaches. this boy is studying music; one year ago he practiced two hours daily on the piano and studied from three to five hours besides. this year his work has been increased; he is now troubled with severe headaches, and after continued near work for some time letters become blurred and run together. this boy is far sighted and astigmatic; glasses will correct his defect, and it will be interesting to note whether his eyes will eventually grow into near sighted ones. i have several cases where the defective vision has been due entirely to other causes, such as inflammation of the cornea, weakening this part of the eye, and the effect in trying to see producing an elongation of the anterior portion of the eyeball, and this in turn producing myopia. the eye of the indian does not differ materially from that of any deeply pigmented race. the eyeball is smaller than in the caucasian, but when we examine the interior we find the same distribution of the blood vessels and same shape of the optic nerves. the pigment deposit in the choroid is excessive and gives, as a background to the retina, a beautiful silvery sheen when examined with the ophthalmoscope. one thing which i noticed particularly was the absence of this excessive deposit of pigment and absence of this watered silk appearance in the half breeds, they taking after the white race. many of the intraocular diseases common among the white children were also absent, especially those diseases which are the result of near work. it is a well known fact among breeders of animals that where animals are too highly or finely bred, the eye is the organ first to show a retrogression from the normal. in an examination by myself some years ago among deaf mutes, i found the offspring of consanguineous marriages much affected, and while not only were many afflicted with inflammatory conditions of the choroid and retina, their average vision was much below the normal. my quoting messrs. lang and barrett's figures was to bring more prominently to the notice of my hearers the fact that the eyes of primitive man resembled the eyes of the lower mammalia and that the natural eye as an organ of vision was hypermetropic, or far sighted, and that civilization was the cause of the myopic or near sighted eye. nature always compensates in some way. i grant that the present demands of civilization could not be filled by the far sighted eye, but the evil which is the outgrowth of present demands does not stop when we have reached the normal eye, but the cause once excited, the coats of this eye continue to give way, and myopia or a near sighted condition is the result. among three hundred indians examined, i found when i got to the creeks, a tribe which has been semi-civilized for many years, myopia to be the prevailing visual defect. without going into statistics, i am convinced from my experience that the state must look into this subject and give our public school system of education more attention, or we, as a people, will be known as a "spectacled race." myopia or short-sightedness among the germans is growing at a tremendous rate. while i do not believe that the german children perform more work than our own children, there is one cause for this defect which has never been touched upon by writers, and that is the shape of the head. the broad, flat face, or german type, as i would call it, has not the deep orbit of the more narrow, sharp-featured face of the american type. the eye of the german standing out more prominently, and, in consequence, less protected, is thereby more prone to grow into a near-sighted eye. one of the significant results of hard study was recently brought to my notice by looking over the statistics on the schools of munich in . in those schools , children suffered from defective sight, boys and , girls. of , boys in the first or elementary class, are short-sighted; in the second, ; in the third, ; in the fourth, ; in the fifth, ; in the sixth, ; and in the last and seventh, . the number of short-sighted boys, therefore, from the first class to the seventh increases about three-fold. in the case of girls, the increase is from to . these statistics in themselves show us the effects of overwork, incessant reading or study by defective gas or lamp light, or from an over-stimulating light, as the arc light, late hours, dissipation, and frequent rubbing of the eye, also fatigue, sudden changes from darkness to light, and, what is probably worse than all, reading on railway trains. the constant oscillations of the car cause an over-activity of the muscle of accommodation, which soon becomes exhausted; the brain willing the eye to give it a clear photograph continues to force the ciliary muscle, which muscle governs the accommodation, in renewed activity, and the result may easily be foretold. the fond parents finding that the vitiated air of the city is making their once rosy-cheeked children turn pale, seek a remedy in the fresh air of the country. the children find their way to city schools; this necessitates traveling so many miles a day in railway cars. the children take this opportunity of preparing their studies while _en route_ to the city, and here is where they get their first eye-strain. children have the example set them by their parents or business men, who read the daily papers on the trains. children are great imitators, and when their attention is called to the evil, quote their parents' example, and they follow it. no wonder each generation is growing more effeminate. the light in sick rooms should never fall directly on the eyes, nor should the rooms be either too dark or too light. the esquimaux and indians long ago noted the fact that sunlight reflected from freshly fallen snow would soon cause blindness. the natives of northern africa blacken themselves around the eyes to prevent ophthalmia from the glare of the hot sand. in fiji the natives, when they go fishing, blacken their faces. my friend. dr. bartelott, presented me with a pair of eye protectors, which he brought from alaska. the natives use them to protect themselves from snow blindness. these snow spectacles, or snow eyes, as they are called, are usually made out of pine wood, which is washed upon their shores, drift wood from southern climes. the posterior surface is deeply excavated, to prevent its obstructing the free motion of the eye lids; on each side a notch is cut at the lower margin to allow a free passage for the tears. the upper margin of the front surface is more prominent than the under, to act as a shade to the eyes. the inner surface is blackened to absorb the excessive light. the openings are horizontal slits. the eyes are thus protected from the dazzling effect of the light. my friend, dr. grady, of omaha, communicated to me a history of three hunters who almost lost their eyesight by too long exposure to the bright rays of the sun falling on snow. the abuse of tobacco leads to impairment of vision in the growing youth. cigarette smoking is an evil. i am inclined to believe that the poison inhaled arrests the growth of boys; surely it prevents a mental development, and, when carried to excess, affects vision more by lessening the power of nerve conduction than acting directly on the eye. it is not the one cigarette which the boy smokes that does the harm, but it is the one, two, or three packages smoked daily. this excessive smoking thoroughly perverts all the functions which should be at their best to aid this growing youth. first we have failing digestion, restless nights, suspension of growth, lack of mental development, the loss of nerve tone, loss of the power of accommodation in vision, failing sight, headaches, enfeeblement of the heart. let a man who is a habitual smoker of cigars attempt to smoke even one package of cigarettes and he will complain of nausea, dry throat, and loss of appetite. if a strong man is so much affected by this poison, how much less can a boy resist the inroads of such poisons? in germany the law forbids the sale of cigarettes to growing boys. new york state has a similar law, and why should our own or any other state be behind in passing prohibitory laws against this evil?--and this is a growing evil. i have never seen a case of tobacco amblyopia in boyhood, but such a condition is not infrequent in adults. in boys the action of nicotine acts especially upon the heart, the impulse is rendered weaker and intermittent, and many young boys lay the seeds of organic disease which sooner or later culminates fatally. boys should be prohibited from smoking, first by their parents, second by law, but not such laws whose enforcement is a failure, third by placing a heavy fine upon dealers who sell to minors. the pernicious evil of intoxication is no less an evil upon the nervous system of a youth than is the habit of cigarette smoking, but, fortunately, this habit is less common. having traced from aboriginal man to the present civilized individual the cause of his myopia, what must we do to prevent a further deterioration of vision? unfortunately, the physician of our country is not, as i am told, like the japanese physician. our medical men are called to attend people who are ill and to try to get them well--the japanese physician is paid only to keep his patients in health. the first effort parents should make is to see that their children have plenty of outdoor exercise. good, warm clothing in winter, and light texture cloth in summer. a great difference of opinion exists as to the age at which a child should begin its studies. i feel sure that the boy who commences his studies at ten will far outrun the one who commences study at six. every child should commence his lessons in the best kindergarten, the nursery. let object lessons be his primer--let him be taught by word of mouth--then, when his brain is what it should be for a boy of ten, his eyes will be the better able to bear the fatigue of the burdens which will be forced upon him. listen to what milton has left on record as a warning to those young boys or girls who insist upon reading or studying at night with bad illumination. "my father destined me, from a child, for the pursuits of polite learning, which i prosecuted with such eagerness that, after i was twelve years old, i rarely retired to bed, from my lucubrations, till midnight. this was the first thing which proved pernicious to my eyes, to the natural weakness of which were added frequent headaches." milton went blind when comparatively a young man, and it was always to him a great grief. galileo, the great astronomer, also went blind by overwork. it was written of him, "the noblest eye which ever nature made is darkened--an eye so privileged, and gifted with such rare powers, that it may truly be said to have seen more than the eyes of all that are gone, and to have opened the eyes of all that are to come." when the defect of far sightedness or near sightedness exists, we have but one recourse--_spectacles_. some time ago i published, in the _medical and surgical reporter_ an article on the history of spectacles. the widespread interest which this paper created has stimulated me to continue the research, and since this article appeared i have been able to gather other additional historical data to what has been described as an invention for "poor old men when their sight grows weak." the late wendell phillips, in his lecture on the "lost arts," speaks of the ancients having magnifying glasses. "cicero said that he had seen the entire _iliad_, which is a poem as large as the new testament, written on a skin so that it could be rolled up in the compass of a nut shell;" it would have been impossible either to have written this, or to have read it, without the aid of a magnifying glass. in parma, a ring , years old is shown which once belonged to michael angelo. on the stone are engraved the figures of seven women. you must have the aid of a glass in order to distinguish the forms at all. another _intaglio_ is spoken of--the figure is that of the god hercules; by the aid of glasses, you can distinguish the interlacing muscles and count every separate hair on the eyebrows. mr. phillips again speaks of a stone inches long and wide containing a whole treatise on mathematics, which would be perfectly illegible without glasses. now, our author says, if we are unable to read and see these minute details without glasses, you may suppose the men who did the engraving had pretty strong spectacles. "the emperor nero, who was short sighted, occupied the imperial box at the coliseum, and, to look down into the arena, a space covering six acres, the area of the coliseum, was obliged, as pliny says, to look through a ring with a gem in it--no doubt a concave glass--to see more clearly the sword play of the gladiators. again, we read of mauritius, who stood on the promontory of his island and could sweep over the sea with an optical instrument to watch the ships of the enemy. this tells us that the telescope is not a modern invention." lord kingsborough, speaking of the ancient mexicans, says: "they were acquainted with many scientific instruments of strange invention, whether the telescope may not have been of the number is uncertain, but the thirteenth plate of _dupaix's monuments_, part second, which represents a man holding something of a similar nature to his eye, affords reason to suppose that they knew how to improve the powers of vision. our first positive knowledge of spectacles is gathered from the writings of roger bacon, who died in .[ ] bacon says: "this instrument (a plano-convex glass or large segment of a sphere) is useful to old men and to those who have weak eyes, for they may see the smallest letters sufficiently magnified." [footnote : _med. and surg. reporter_.] alexander de spina, who died in , had a pair of spectacles made for himself by an optician who had the secret of their invention. de spina was so much pleased with them that he made the invention public. monsieur spoon fixes the date of the invention between and . in a manuscript written in by pissazzo, the author says: "i find myself so pressed by age that i can neither read nor write without those glasses they call spectacles, lately invented, to the great advantage of poor old men when their sight grows weak." friar jordan, who died in pisa in , says in one of his sermons, which was published in , that "it is not twenty years since the art of making spectacles was found out, and is indeed one of the best and most necessary inventions in the world." in the fourteenth century spectacles were not uncommon and italy excelled in their manufacture. from italy the art was carried into holland, then to nuremberg, germany. in a church in florence is a fresco representing st. jerome ( ). among the several things represented is an inkhorn, pair of scissors, etc. we also find a pair of spectacles, or _pince-nez_--the glasses are large and round and framed in bone. it was not until that maurolicus, of messina, pointed out the cause of near sightedness and far sightedness and explained how concave glasses corrected the former and convex glasses the latter defect. in the wake of advanced, education stalks the spectacle age. any one watching a passing crowd cannot fail but note the great number of people wearing spectacles. unfortunately it is not limited to adults, but our youths of both sexes go to make up this army of ametropes. at what age should children first wear glasses? this is a much debatable question. where there is simply a defect of vision i should never prescribe a pair of glasses for a child under ten years of age. a child under this age runs many risks of injury to the eyeball by accident to the glasses, and to cut the eye with glass is a very serious affair. rather let a child go without study, or even with impaired vision, than run the risk of a permanent loss of sight. another source of evil i must call your attention to, and that is the indiscriminate use of glasses given by itinerant venders of spectacles who claim a thorough knowledge of the eye, who make examination free, but charge double price for glasses. persons, before submitting themselves into the hands of opticians, should know that they are not suffering from any incipient disease of their eyes. i do not, for a moment, claim that a practical optician cannot give you a pair of glasses which will make you see--he does nothing more than hand you a number of pairs of glasses and you select the one pair which you think answers the purpose. how can anyone but a medical man know that the impairment of vision does not arise from diminished sensibility of the retina? if so, the glasses just purchased, which may be comfortable for a time, may cause an irreparable loss of vision. every ophthalmic surgeon will tell you that he has had a number of such cases. do not be misguided by purchasing cheap spectacles. glasses advertised as having "remarkable qualities" are always to be passed by. they have "remarkable qualities;" they always leave the person wearing them worse at the end of a few months. whenever an eye finds relief in a shaded or colored glass, something is going wrong with the interior of that eye. seek advice, but do not trust the eyes of yourself, much less those of your children, in the hands of the opticians who advertise their examinations free. such individuals should be brought before a tribunal and the matter sifted as to whether the sense of sight is less to be taken care of than if that same patient were ill with pneumonia and a druggist were to prescribe remedies which might or might not aid this patient. if one man must comply with the law, why should not the other? our medical colleges are lengthening the course of studies; the advances in the various departments of science demand this. it is by the aid of the ophthalmoscope that many obscure diseases are diagnosed, and while it is impossible for every young man who obtains a diploma to become thoroughly proficient in the use of this instrument, yet the eye shows to him many conditions which guide him to the road of successful treatment. think of a case of optic neuritis--inflammation of the optic nerve--going to an optician and fitting one set of glasses after another until the patient suddenly discovers that blindness is inevitable. many individuals, and very intelligent ones at that, think that so long as a glass makes them see, that is all they need. when we know that scarcely two eyes are alike, we can at once feel that it is very important that each eye should be properly adjusted for a glass; by this we are sure of having comfort in reading and preserving vision. there is a very important defect in vision which should be detected as early in life as possible, and that is color blindness. the boy who is a color blind will always remain a color blind, and as forty in every , of the male sex are color blind, it is essential that they know their defect, and train their course accordingly. it would be to the advantage of all boys to undergo such an examination once in their school life; a color blind would be useless where the selection of color entered into his life work. if a boy had a talent for drawing or engraving, and were color blind, he would make a success of his life, whereas if he would attempt to mix paints of different colors he would be a failure. i shall not dwell upon the scientific part of color blindness, nor discuss either the young-helmholtz or the hering theories of color defect, but shall deal with its practical use in everyday life. until the year , very little was known about color blindness, and much less written about it. dr. george wilson, in , wrote several articles, which were published in the _edinburgh monthly journal of medical science._ these articles created such an interest in the scientific world that dr. wilson brought out a book, entitled "researches on color blindness," two years later. so thoroughly did dr. wilson sift this subject that no writer up to the present day has added anything practical to what was then known. dr. wilson writes in his preface: "the most practical relation of color blindness is that which it has to railway and ship signals." he further states: "the professions for which color blindness most seriously disqualifies are those of the sailor and railway servant, who have daily to peril human life and property on the indication which a colored flag or a lamp seems to give." dr. bickerton, in an article on this same subject, speaking of the careless way in which lights were used on ships at sea, says: "until the year , there were no definite rules regarding the carrying of lights at night by vessels at sea.... at this time the subject of color blindness had not awakened the attention of practical observers, and had the fact been known that between three and four per cent. of the whole male population are color blind, some other mode might have been devised to indicate the positions of vessels at night than by showing red and green lights." if it is so very important to have sailors with good color perception, where, at least, four men are on the lookout, how much more important is it to have our engine drivers with perfect color perception, where one man alone watches the signal of safety or danger. the growth of our railway system is constantly increasing. we have to-day probably , men employed in this service. the boys attending public schools to-day in a few years will have to fill the ranks of these men. how important for these boys to know that they have not this defect. if the forty boys in every , are found, what is to be done with them? the engraver, the wood cut engraver, the etcher, all wish apprentices. i am also informed that these occupations pay well. it requires talent to fill them, and here is an opening for the color blind. hear what a color blind writes:[ ] "i beg to offer some particulars of my own case, trusting it may be of use to you. i am an engraver, and strange as it may appear, my defective vision is, to a certain extent, a useful and valuable quality. thus, an engraver has two negative colors to deal with, i.e., white and black. now, when i look at a picture, i see it only in white and black, or light and shade, and any want of harmony in the coloring of a picture is immediately made manifest by a corresponding discord in the arrangement of its light and shade or, as artists term it, the _effect_. i find at times many of my brother engravers in doubt how to translate certain colors of pictures which to me are matters of decided certainty and ease. thus, to me it is valuable." having already spoken about the importance of having all boys undergo an examination for color blindness once in their school lives, we have two very good reasons for making this suggestion. [footnote : wilson, p. .] first, prevent a boy following a trade or occupation where he is incapacitated, and, secondly, let him be trained for a certain trade or occupation when the defect exists. the savage races possess the perception of color to a greater degree than do civilized races. i have just concluded an examination of indian children; were boys. had i selected white boys from various parts of the united states i would have found at least five color blinds; among the indian boys i did not find a single one. some years ago i examined indian boys and found two color blind, a very low percentage when compared with the whites. among the indian girls i did not find any. when we know that only two females in every , among whites are color blind, it is not surprising that i did not find any examples among the indian girls. the usual tests for color blindness are the matching of wools; the common error the color blind falls into is matching a bright scarlet with a green. on one occasion, a color blind gentleman found fault with his wife for wearing, as he thought, a bright scarlet dress, when in point of fact she was wearing a bright green. another color blind who was very fond of drawing, once painted a red tree in a landscape without being aware that he had done so. among the whites it affects all classes. it is found as relatively common among the intelligent as the illiterate, and unfortunately, up to the present, we have not discovered any remedy for this defect. without quoting many instances where a color blind man was responsible for accidents at sea, i must quote a case where an officer on the watch issued an order to "port" his vessel, which, if his order had been carried out, would have caused a collision, and a probable serious loss of life. the letter was written by capt. coburn, and is to be found in the _mercantile marine reporter_, vol. xiv. "the steamer neera was on a voyage from liverpool to alexandria. one night, shortly after passing gibraltar, at about . p.m., i went on the bridge, which was then in charge of the third officer, a man of about forty-five years of age, and who up to that time i had supposed to be a trustworthy officer, and competent in every way. i walked up and down the bridge until about p.m., when the third officer and i almost simultaneously saw a light at about two points on the starboard bow. i at once saw it was a green light, and knew that no action was called for. to my surprise, the third officer called out to the man at the wheel, 'port,' which he was about to do, when i countermanded the order, and told him to steady his helm, which he did, and we passed the other steamer safely about half a mile apart. i at once asked the third officer why he had ported his helm to a green light on the starboard bow, but he insisted it was a red light which he had first seen. i tried him repeatedly after this, and although he sometimes gave a correct description of the color of the light, he was as often incorrect, and it was evidently all guesswork. on my return, i applied to have him removed from the ship, as he was, in my opinion, quite unfit to have charge of the deck at night, and this application was granted. after this occurrence i always, when taking a strange officer to sea, remained on the bridge with him at night until i had tested his ability to distinguish colors. i cannot imagine anything more dangerous or more likely to lead to fatal accidents than a color blind man on a steamer's bridge." a similar experience is thus related by capt. heasley, of liverpool: "after passing through the straits of gibraltar, the second officer, who had charge of the deck, gave the order to 'port,' much to my astonishment, for the lights to be seen about a point on the starboard bow were a masthead and green light, but he maintained that it was a masthead and red, and not until both ships were nearly abreast would he acknowledge his mistake. i may add that during the rest of the voyage i never saw him making the same mistake. as a practical seaman i consider a great many accidents at sea arise from color blindness." dr. farquharson has brought this subject before the house of commons in england and measures are being taken which will insure to the traveling public immunity from accidents at sea. i need not mention that the majority of railways of our country have a system of examinations which prevents a color blind entering their service. dr. wilson makes the suggestion that he noticed a singular expression in the eyes of certain of the color blind difficult to describe. "in some it amounted to a startled expression, as if they were alarmed; in others, to an eager, aimless glance, as if seeking to perceive something but unable to find it; and in certain others to an almost vacant stare, as if their eyes were fixed upon objects beyond the limit of vision. the expression referred to, which is not at all times equally pronounced, never altogether leaves the eyes which it seems to characterize." dr. b. joy jeffries, of boston, has recently written an article on this same topic, but unfortunately i have not his pamphlet at hand to quote his views on this subject. in this lecture i have shown that the normal eye is far sighted. the mammalia have this kind of an eye; the indian the same. the white man is fast becoming near sighted. the civilized indian is also showing the effects of continuous near work; and now the question arises. what are we to do to prevent further deterioration of vision? the fault lies at our own doors. let us try to correct these now existing evils, so that future generations will, instead of censuring us, thank us for our wisdom. to aid in a feeble way for the protection of posterity i have formulated ten rules on the preservation of vision: ( ) do not allow light to fall upon the face of a sleeping infant. ( ) do not allow babies to gaze at a bright light. ( ) do not send children to school before the age of ten. ( ) do not allow children to keep their eyes too long on a near object, at any one time. ( ) do not allow them to study much by artificial light. ( ) do not allow them to use books with small type. ( ) do not allow them to read in a railway carriage. ( ) do not allow boys to smoke tobacco, especially cigarettes. ( ) do not necessarily ascribe headaches to indigestion. the eyes may be the exciting cause. ( ) do not allow the itinerant spectacle vender to prescribe glasses. * * * * * the water molecule.[ ] [footnote : translated from the _pharmaceutische centralhalle_, by a.g. vogeler.--_western druggist_.] by a. ganswindt. "water consists of one atom of oxygen and two atoms of hydrogen." this proposition will not be disputed in the least by the author; still, it may be profitable to indulge in a few stereo-chemic speculations as to the nature of the water molecule and to draw the inevitable conclusions. from the time of the discovery, some years ago, that water is a compound body, made up of oxygen and hydrogen, the notion prevailed up to within a quarter of a century that it was composed of even equivalents of the elements named, and all but the youngest students of chemistry well remember how its formula was written ho, the atomic weight of oxygen being expressed by , making the molecular weight of water (h= + o= ) . but the vapor density of water, referred to air, is . , and this number multiplied by the constant . , gives as the molecular weight of water, or exactly twice that accepted by chemists. this discrepancy led to closer observations, and it was eventually found that in decomposing water, by whatever method (excepting only electrolysis), not more than the eighteenth part in hydrogen of the water decomposed was ever obtained, or, in other words, only just one-half the weight deducible from the formula ho = . the conclusion was irresistible that in a water molecule two atoms of hydrogen must be assumed, and, as a natural sequence, followed the doubling of the molecular weight of water to , represented by the modern formula h_{ }o. both the theory and the practice of substitution enable us to further prove the presence of two hydrogen atoms in a water molecule. decomposing water by sodium, only one-half of the hydrogen contained is eliminated, the other half, together with all of the oxygen, uniting with the metal to form sodium hydroxide, h_{ }o + na = h + naho. doubling the amount of sodium does not alter the result, for decomposition according to the equation h_{ }o + na = h_{ } + na_{ }o never happens. introducing the ethyl group into the water molecule and reacting under appropriate conditions with ethyl iodide upon water, the ethyl group displaces one atom of hydrogen, and, uniting with the hydroxyl residue, forms ethyl alcohol, thus: h_{ }o + c_{ }h_{ }i = c_{ }h_{ }oh + hi. halogens do not act directly on water, hence we may not properly speak of halogen substitution products. by the action, however, of phosphorus haloids on water an analogous splitting of the water molecule is again observed, one-half of the hydrogen uniting with the halogen to form an acid, the hydroxyl residue then forming a phosphorus compound, thus: pcl_{ } + h_{ }o = hcl + p(oh)_{ }. now these examples, which might readily be multiplied, prove not only the presence of _two_ hydrogen atoms in the water molecule, but they further demonstrate that these two atoms _differ from each other_ in respect to their form of combination and power of substitution. the two hydrogen atoms are certainly not of equal value, whence it follows that the accepted formula for water: h > o h or as preferred by some: h-o-h, is not in conformity with established facts. expressed as here shown, both hydrogen atoms are assigned equal values, when in fact only _one of the atoms is united to oxygen in form of hydroxyl_, while the second is loosely attached to the univalent hydroxyl group. viewed in this light, water then is decomposed according to the equation: h_{ }o = h + (oh), never in this manner: h_{ }o = h + o. hence, water must be considered as a combination of one hydrogen atom with one molecule of hydroxyl, expressed by the formula h(oh), and it is this atom of hydrogen _not_ united to oxygen which is eliminated in the generation of oxygen or substituted by metals and alkyl groups. the hydrogen in the hydroxyl group cannot be substituted, excepting it be the entire group as such; this is proved by the action of the halogens, in their phosphorus compounds, upon water, when the halogen takes the place of the hydroxyl group, but never that of the hydrogen. now as to some logical deductions from the foregoing considerations. hydrogen is by many looked upon as a true metal. this theory cannot be directly proved by the above, but it is certainly greatly strengthened thereby. to compare. hydrogen is a powerful reducing agent; it is similarly affected by the halogens, the hydroxyl group, the acid radicals, oxygen and sulphur; hydrogen and members of the univalent alkali metals group are readily interchangeable; it forms superoxides analogous to the metals; its analogy to the alkali metals as exhibited in the following: h h(oh) hcl hno_{ } h_{ }so_{ } h_{ }s h_{ }o_{ } k k(oh) kcl kno_{ } na_{ }so_{ } na_{ }s k_{ }o but if we consider hydrogen as a gasiform metal, we naturally arrive at the conclusion that _water is the hydroxide of this gasiform metal_, that is _hydrogen hydroxide_, while gaseous hydrochloric and hydrosulphuric acids would be looked upon as respectively the chloride and the sulphide of the metal hydrogen. this would then lead to curious conclusions concerning the hydroxyl group. this group would, by this theory, become an oxygenated metal radical similar to the hypothetical bismuthyl and uranyl, and yet one in which the metallic character has disappeared as completely as in the ferrocyanic group. an entirely new light is shed by this view upon the composition of hydrogen peroxide, which would be looked at as two free hydroxyl groups joined together thus: (oh)--(oh), analogous to our di-ethyl, diphenyl, dicyanogen, etc. considered as dihydroxyl, it would explain the instability of this compound. the ethers proper would also be placed in a new light by this new conception of the constitution of the water molecule. the hydrogen in the hydroxyl group, as is known, may be substituted by an alkyl group. for instance, an alkyl may be substituted for the hydroxyl hydrogen in an alcohol molecule, when an ether results. according to the new theory this ether will no longer be considered as two alkyl groups connected by an oxygen atom, but as a compound built up on the type of water by the union of an alkyl group and an alkoxyl group. thus ethylic ether would not be represented by c_{ }h_{ } > o, c_{ }h_{ } as heretofore, but by the formula c_{ }h_{ }(oc_{ }h_{ }), which is ethyl-ethoxol. acetone would admit of a similar explanation. finally the assumption of dissimilarity in character of the hydrogen atoms in the water molecule possibly may lead to the discovery of a number of unlocked for isomerides. thus, by appropriate methods, it ought to become possible to introduce the alkyl groups solely into the hydroxyl group (instead of into the place of the loosely attached h-atom). in that case chemists might arrive at an isomeride of methyl alcohol of the formula h.(och_{ }), or at methoxyl hydride, a compound not alcoholic in character, or at a nitroxyl hydride, h(ono_{ }), not of an acidic nature. oxychlorides would be classed with this latter category, that is, they would be looked on as water in which the free hydrogen atom has been substituted by the metal, and the hydrogen atom of the hydroxyl by chlorine. this example, indeed, furnishes a most characteristic illustration of our theory. in the case just now assumed we arrive at the oxychloride; when, however, the metal and chlorine change places in the water molecule, the isomeric hypochlorous salts are the result. it is true that such cases of isomerism are as yet unknown, but we do know that certain metals, in our present state of knowledge, yield oxychlorides only, while others only form hypochlorous salts. this condition also explains why hypochlorites still possesses the bleaching power of chlorine, while the same is not true of oxychlorides. however, it seems needless to multiply examples in further illustration of the theory. * * * * * the formation of starch in leaves. in , bonnet, a genevese naturalist, remarked that leaves immersed in water became covered in the sun with small bubbles of a gas that he compared to small pearls. in , priestley, after discovering that the sojourn of animals in a confined atmosphere renders it irrespirable, investigated the influence of plants placed in the same conditions, and he relates, in these words, the discovery that he made on the subject: "i put a sprig of mint in a quantity of air in which a candle had ceased to burn, and i found that, ten days later, another candle was able to burn therein perfectly well." it is to him, therefore, that is due the honor of having ascertained that plants exert an action upon the atmosphere contrary to that exerted by animals. priestley, however, was not completely master of his fine experiment; he was ignorant of the fact, notably, that the oxygen is disengaged by plants only as long as they are under the influence of light. this important discovery is due to ingenhouse. finally, it was sennebier who showed that oxygen is obtained from leaves only when carbonic acid has been introduced into the atmosphere where they remain. later on, t. de saussure and boussingault inquired into the conditions most favorable to assimilation. boussingault demonstrated, in addition, that the volume of carbonic acid absorbed was equal to that of the oxygen emitted. now we know, through a common chemical experiment, that carbonic acid contains its own volume of oxygen. it was supposed, then, that carbonic acid was decomposed by sunlight into carbon and oxygen. things, however, do not proceed so simply. in fact, it is certain that, before the complete decomposition into carbon and oxygen, there comes a moment in which there is oxygen on the one hand and oxide of carbon (co_{ } = o + co) on the other. the decomposition, having reached this point, can go no further, for the oxide of carbon is indecomposable by leaves, as the following experiment proves. if we put phosphorus and some leaves into an inert gas, such as hydrogen, we in the first place observe the formation of the white fumes of phosphoric acid due to the oxidation of the phosphorus by the oxygen contained in the leaves. this phosphoric acid dissolves in the water of the test glass and the latter becomes transparent again. if, now, we introduce some oxide of carbon, we remark in the sun no formation of phosphoric acid, and this proves that there is no emission of oxygen. [illustration: demonstration that starch is formed in leaves only at the points touched by light.] this latter hypothesis of the decomposition of carbonic acid into a half volume of vapor of carbon and one volume of oxygen being rejected, the idea occurred to consider the carbonic acid in a hydrated state and to write it co_{ }ho. in this case, we should have by the action of chlorophyl: co_{ }ho (carbonic acid) = o (oxygen) + c_{ }h_{ }o_{ } (methylic aldehyde). this aldehyde is a body that can be polymerized, that is to say, is capable of combining with itself a certain number of times to form complexer bodies, especially glucose. this formation of a sugar by means of methylic aldehyde is not a simple hypothesis, since, on the one hand, mr. loew has executed it by starting from methylic aldehyde, and, on the other, we find this glucose in leaves by using fehling's solution. the glucose formed, it is admissible that a new polymerization with elimination of water produces starch. the latter, in fact, through the action of an acid, is capable of regenerating glucose. it may, therefore, be supposed that the decomposition of carbonic acid by leaves brings about the formation of starch through the following transformations: ( ) the decomposition of the carbonic acid with emission of oxygen and production of methylic aldehyde; ( ) polymerization of methylic aldehyde and formation of glucose; ( ) combination of several molecules of glucose with elimination of water; formation of starch. starch is thus the first stable product of chlorophylian activity. is there, in fact, starch in leaves? it is easy to reveal its presence by the blue coloration that it assumes in contact with iodine in a leaf bleached by boiling alcohol. mr. deherain has devised a nice method of demonstrating that this formation of starch, and consequently the decomposition of carbonic acid, can occur only under the influence of sunlight. he pointed it out to us in his course of lectures at the school of grignon, and asked us to repeat the experiment. we succeeded, and now make the _modus operandi_ known to our readers. the leaf that gave the best result was that of the _aristolochia sipho_. the leaf, adherent to the plant, is entirely inclosed between two pieces of perfectly opaque black paper. that which corresponds to the upper surface of the limb bears cut-out characters, which are here the initials of mr. deherain. the two screens are fastened to the leaf by means of a mucilage of gum arabic that will easily cede to the action of warm water at the end of the experiment. the exposure is made in the morning, before sunrise. at this moment, the leaf contains no starch; that which was formed during the preceding day has emigrated during the night toward the interior of the plant. after a few hours of a good insolation, the leaf is picked off. then the gum which holds the papers together is dissolved by immersion in warm water. the decolorizing is easily effected through boiling alcohol, which dissolves the chlorophyl and leaves the leaf slightly yellowish and perfectly translucent. there is nothing more to do then but dip the leaf in tincture of iodine. if the insolation has been good, and if the screens have been well gummed so that no penumbra has been produced upon the edge of the letters, a perfectly sharp image will be instantly obtained. the excess of iodine is removed by washing with alcohol and water, and the leaf is then dried and preserved between the leaves of a book. it is well before decolorizing the leaf to immerse it in a solution of potassa; the chlorophylian starch then swells and success is rendered easier.--_lartigue and malpeaux, in la nature_. * * * * * standards and methods for the polarimetric estimation of sugars.[ ] [footnote : report to the united states internal revenue department by c.a. crampton, chemist of u.s. internal revenue; h.w. wiley, chief chemist of u.s. department of agriculture; and o.h. tittmann, assistant in charge of weights and measures, u.s. coast and geodetic survey.] section , paragraph , of the act entitled "an act to reduce revenue and equalize duties on imports and for other purposes," approved october , , provides: " . that on and after july , eighteen hundred and ninety-one, and until july , nineteen hundred and five, there shall be paid, from any moneys in the treasury not otherwise appropriated, under the provisions of section three thousand six hundred and eighty-nine of the revised statutes, to the producer of sugar testing not less than ninety degrees by the polariscope, from beets, sorghum, or sugar cane grown within the united states, or from maple sap produced within the united states, a bounty of two cents per pound; and upon such sugar testing less than ninety degrees by the polariscope, and not less than eighty degrees, a bounty of one and three-fourth cents per pound, under such rules and regulations as the commissioner of internal revenue, with the approval of the secretary of the treasury, shall prescribe." it is the opinion of this commission that the expression "testing ... degrees by the polariscope," used with reference to sugar in the act, is to be considered as meaning the percentage of pure sucrose the sugar contains, as ascertained by polarimetric estimation. it is evident that a high degree of accuracy is necessary in the examination of sugars by the bureau of internal revenue, under the provisions of this act, inasmuch as the difference of one-tenth of one per cent. in the amount of sucrose contained in a sugar may, if it is on the border line of °, decide whether the producer is entitled to a bounty of ¾ cents per pound (an amount nearly equivalent to the market value of such sugar) or to no bounty whatever. it is desirable, therefore, that the highest possible degree of accuracy should be secured in the work, for while many sugars will doubtless vary far enough from either of the two standard percentages fixed upon in the act, viz., ° and °, to admit of a wide margin of error without material consequences, yet a considerable proportion will approximate to them so closely that a difference of a few tenths of a degree in the polarization will change the classification of the sugar. a very high degree of accuracy may be obtained in the optical estimation of sugars, if the proper conditions are observed. such conditions are ( ) accurately graded and adjusted instruments, weights, flasks, tubes, etc.; ( ) skilled and practiced observers; ( ) a proper arrangement of the laboratories in which the work is performed; and ( ) a close adherence to the most approved methods of manipulation. on the other hand, if due observance is not paid to these conditions, the sources of error are numerous, and inaccurate results inevitable. we will endeavor to point out in this report the best means of meeting the proper conditions for obtaining the highest degree of accuracy consistent with fairly rapid work. it would be manifestly impossible to observe so great a refinement of accuracy in this work as would be employed in exact scientific research. this would be unnecessary for the end in view, and impossible on account of the amount of time that would be required. i.--instruments and apparatus. it is of the greatest importance that the polariscopes and all apparatus used in the work shall be carefully and accurately adjusted and graduated, and upon a single and uniform system of standardization. recent investigations of the polarimetric work done in the customs branch of the treasury department have shown that a very considerable part of the want of agreement in the results obtained at the different ports was due to a lack of uniformity in the standardization of the instruments and apparatus. _(a.) the polariscope._--there are many different forms of this instrument used. some are adapted for use with ordinary white light, and some with monochromatic light, such as sodium ray. they are graduated and adjusted upon various standards, all more or less arbitrary. some, for example, have their scales based upon the displacement of the polarized ray produced by a quartz plate of a certain thickness; others upon the displacement produced by an arbitrary quantity of pure sucrose, dissolved and made up to a certain volume and polarized in a certain definite length of column. it would be very desirable to have an absolute standard set for polariscopic measurements, to which all instruments could be referred, and in the terms of which all such work could be stated. this commission has information that an investigation is now in progress under the direction of the german imperial government, having for its end and purpose the determination of such data as will serve for the establishment of an absolute standard. when this is accomplished it can easily be made a matter of international agreement, and all future forms of instruments be based upon it. this commission would suggest that the attention of the proper authorities should be called to the desirability of official action by this government with a view to co-operation with other countries for the adoption of international standards for polarimetric work. until this is done, however, it will be necessary for the internal revenue bureau to adopt, provisionally, one of the best existing forms of polariscope, and by carefully defining the scale of this instrument, establish a basis for its polarimetric work which will be a close approximation to an absolute standard, and upon which it can rely in case of any dispute arising as to the results obtained by the officers of the bureau. for the instrument to be provisionally adopted by the internal revenue bureau, this commission would recommend the "half shadow" instrument made by franz schmidt & haensch, berlin. this instrument is adapted for use with white light illumination, from coal oil or gas lamps. it is convenient and easy to read, requiring no delicate discrimination of colors by the observer, and can be used even by a person who is color blind. this form of instrument is adjusted to the ventzke scale, which, for the purposes of this report, is defined to be such that ° of the scale is the one hundredth part of the rotation produced in the plane of polarization of white light in a column mm. long by a standard solution of chemically pure sucrose at . ° c. the standard solution of sucrose in distilled water being such as to contain, at . ° c. in c.c., . grms. of sucrose. in this definition the weights and volumes are to be considered as absolute, all weighings being referred to a vacuum. the definition should properly be supplemented with a statement of the equivalent circular rotation in degrees, minutes, and seconds that would be produced by the standard solution of sugar used to read ° on the scale. this constant is now a matter of investigation, and it is thought best not to give any of the hitherto accepted values. when this is established, it is recommended that it be incorporated in a revision of the regulations of the internal revenue relative to sugar, in order to make still more definite and exact the official definition of the ventzke scale. the instruments should be adjusted by means of control quartz plates, three different plates being used for complete adjustment, one reading approximately ° on the scale, one °, and one °. these control quartz plates should have their exact values ascertained in terms of the ventzke scale by the office of weights and measures by comparison with the standard quartz plates in possession of that office, in strict accordance with the foregoing definition, and should also be accompanied by tables giving their values for temperatures from ° to °. _(b.) weights._--the weights used should be of solid brass, and should be standardized by the office of weights and measures. _(c.) flask._--the flasks used should be of such a capacity as to contain at . ° c. . cubic centimeters, when filled in such a manner that the lowest point of the meniscus of the surface of the liquid just touches the graduation mark. the flasks will be standardized to contain this volume in order that the results shall conform to the scale recommended for adoption without numerical reduction of the weighings to vacuo. they should be calibrated by the office of weights and measures. _(d.) tubes._--the tubes used should be of brass or glass, and millimeters in length, and should be measured by the office of weights and measures. _(e.) balances._--the balances used should be sensitive to at least one milligramme. ii.--skilled observers. the commission recommends that the work of polarizing sugars be placed in the hands of chemists, or at least of persons who are familiar with the use of the polariscope and have some knowledge of the theory of its construction and of chemical manipulations. to this end we would suggest that applicants for positions where such work is to be done should be obliged to undergo a competitive examination in order to test their fitness for the work that is to be required of them. iii.--arrangement of laboratories. the arrangement of the rooms in which polarizations are performed has an important bearing upon the accuracy of the results obtained. polariscopic observations are made more readily and accurately if the eye of the observer is screened from diffused light; therefore, a partial darkening of the room, which may be accomplished by means of curtains or hangings, is an advantage. on the other hand, the temperature at which the observation is made has a very considerable influence upon the results obtained, so that the arrangements for darkening the room must not be such as will interfere with its proper ventilation. otherwise the heat from the lamps used, if confined within a small room, will cause considerable variations in the temperature of the room from time to time. the proper conditions will best be met, in our opinion, by placing the lamps either in a separate room from that in which the instruments are, and perforating the wall or partition between the two rooms for the light to reach the end of the instruments, or in a ventilated hood with the walls perforated in a like manner. by lining the wall or partition on both sides with asbestos paper, and inserting a plate of plane glass in the aperture through which the light passes, the increase of temperature from the radiation of the lamp will be still further avoided. with the lamps separated from the instruments in this manner, the space in which the instruments are contained is readily darkened without much danger of its temperature being unduly raised. some light, of course, is necessary for reading the scales, and if artificial light is employed for this purpose, the sources chosen should be such that as little heat as possible will be generated by them. small incandescent electric lights are best for such purpose. refinements of this kind cannot always be used, of course, but the prime requisite with reference to the avoidance of temperature errors is that all operations--filling the flasks and tubes, reading the solutions, controlling the instrument with standard quartz plates, etc.--should be done at one and the same temperature, and that this temperature be a constant one, that is, not varying greatly at different hours of the day. for example, the room should not be allowed to become cold at night, so that it is at low temperature in the morning when work is begun, and then rapidly heated up during the day. the polariscope should not be exposed to the direct rays of the sun during part of the day, and should not be near artificial sources of heat, such as steam boilers, furnaces, flues, etc. the tables upon which the instruments stand should be level. iv.--methods of manipulation. the methods of manipulation used in the polarization of sugar are of prime importance. they consist in weighing out the sugar, dissolving it, clarifying the solution, making it up to standard volume, filtering, filling the observation tube, regulating the illumination, and making the polariscopic reading. the proper conduct of these processes, in connection with the use of accurately graduated apparatus, is the only surety against the numerous sources of error which may be encountered. different sugars require different treatment in clarification, and much must necessarily be left to the judgment and experience of the operator. the following directions are based upon various official procedures such as the one used in the united states custom houses, the method prescribed by the german government, etc. they embody also the result of recent research in regard to sources of error in polarimetric estimation of sugar: directions for the polarization of sugar. .--_description of instrument and manner of using._ the instrument employed is known as the half shadow apparatus of schmidt and haensch. it is shown in the following cut. [illustration] the tube n contains the illuminating system of lenses and is placed next to the lamp; the polarizing prism is at o, and the analyzing prism at h. the quartz wedge compensating system is contained in the portions of the tube marked f, e, g, and is controlled by the milled head m. the tube j carries a small telescope, through which the field of the instrument is viewed, and just above is the reading tube k, which is provided with a mirror and magnifying lens for reading the scale. the tube containing the sugar solution is shown in position in the trough between the two ends of the instrument. in using the instrument the lamp is placed at a distance of at least mm. from the end; the observer seats himself at the opposite end in such a manner as to bring his eye in line with the tube j. the telescope is moved in or out until the proper focus is secured, so as to give a clearly defined image, when the field of the instrument will appear as a round, luminous disk, divided into two halves by a vertical line passing through the center, and darker on one half of the disk than on the other. if the observer, still looking through the telescope, will now grasp the milled head m and rotate it, first one way and then the other, he will find that the appearance of the field changes, and at a certain point the dark half becomes light, and the light half dark. by rotating the milled head delicately backward and forward over this point he will be able to find the exact position of the quartz wedge operated by it, in which the field is neutral, or of the same intensity of light on both halves. [illustration] the three different appearances presented by the field are best shown in the above diagram. with the milled head set at the point which gives the appearance of the middle disk as shown, the eye of the observer is raised to the reading tube, k, and the position of the scale is noted. it will be seen that the scale proper is attached to the quartz wedge, which is moved by the milled head, and attached to the other quartz wedge is a small scale called a vernier which is fixed, and which serves for the exact determination of the movable scale with reference to it. on each side of the zero line of the vernier a space corresponding to nine divisions of the movable scale is divided into ten equal parts. by this device the fractional part of a degree indicated by the position of the zero line is ascertained in tenths; it is only necessary to count from zero, until a line is found which makes a continuous line with one on the movable scale. with the neutral field as indicated above, the zero of the movable scale should correspond closely with the zero of the vernier unless the zero point is out of adjustment. if the observer desires to secure an exact adjustment of the zero of the scale, or in any case if the latter deviates more than one-half of a degree, the zero lines are made to coincide by moving the milled head and securing a neutral field at this point by means of the small key which comes with the instrument, and which fits into a nipple on the left hand side of f, the fixed quartz wedge of the compensating system. this nipple must not be confounded with a similar nipple on the right hand side of the analyzing prism, h, which it fits as well, but which must never be touched, as the adjustment of the instrument would be seriously disturbed by moving it. with the key on the proper nipple it is turned one way or the other until the field is neutral. unless the deviation of the zero be greater than . °, it will not be necessary to use the key, but only to note the amount of the deviation, and for this purpose the observer must not be content with a single setting, but must perform the operation five or six times, and take the mean of these different readings. if one or more of the readings show a deviation of more than . ° from the general average, they should be rejected as incorrect. between each observation the eye should be allowed to seconds of rest. the "setting" of the zero having been performed as above, the determination of the accurate adjustment of the instrument by means of the "control" quartz plates is proceeded with. three such plates will be furnished with each polariscope, which have "sugar values" respectively approximating °, °, and °. these values may vary with the temperature, and tables are furnished with them which give their exact value at different temperatures, from ° to ° c. one of these plates is placed in the instrument, and the field observed; it will be seen that the uniform appearance of the field is changed. the milled head is turned to the right until the exact point of neutrality is re-established, just as described above in setting the zero. the scale is read, the observation repeated, the reading taken again, and so on until five or six readings have been made. the average is taken, readings being rejected which show a divergence of more than . , and the result corrected for the deviation of the zero point, if any was found, the deviation being added if it was to the left, and subtracted if to the right. if the adjustment of the instrument be correct, the result should be the value of the control plate used, as ascertained from the table, for the temperature of °. each of the three plates is read in the instrument in this way. a variation of . from the established values may be allowed for errors of observation, temperature, etc., but in the hands of a careful observer a deviation greater than this with one of the three plates, after a careful setting of the zero, shows that the instrument is not accurately adjusted. the complete verification of the accurate adjustment of the polariscope by means of three control plates, as given above, should be employed whenever it is set up for the first time by the officer using it, whenever it has sustained any serious shock or injury, and whenever it has been transported from one place to another. it should also be done at least once a week while the instrument is in active use. after the complete verification has been performed as described, further checking of the instrument is done by means of one control plate alone, the one approximating °, and the setting of the zero point is dispensed with, the indication of the scale for sugar solutions being corrected by the amount of deviation shown in the reading of the ° control plate from its established value as ascertained from the table, at the temperature of the room. for example: a sugar solution polarizes . ; the control plate just before had given a polarization of . , the temperature of the room during both observations being ° c. according to the table the value of the control plate at ° c. is . ; the reading is, therefore, . too low, and . is added to the reading of the sugar solution, making the corrected result . . the temperature of the room should be ascertained from a standardized thermometer placed close to the instrument and in such a position as to be subject to the same conditions. preparation of the sugar solution for polarization. if the sample is not entirely uniform it must be thoroughly mixed before weighing out, after all the lumps are broken up, best with a mortar and pestle. then . grammes are weighed out on the balance in the tared german silver dish furnished for this purpose. care must be taken that the operations of mixing and weighing out are not unduly prolonged, otherwise the sample may easily suffer considerable loss of moisture, especially in a warm room. the portion of sugar weighed out is washed by means of a jet from a wash bottle into a c.c. flask, the dish being well rinsed three or four times and the rinsings added to the contents of the flask. the water used must be either distilled water or clear water which has been found to have no optical activity. after the dish has been thoroughly rinsed, enough water is added to bring the contents of the flask to about c.c. and it is gently rotated until all the sugar has dissolved. the flask should be held by the neck with the thumb and finger, and the bulb not handled during this operation. care must be taken that no particle of the sugar or solution is lost. to determine if all the sugar is dissolved, the flask is held above the level of the eye, in which position any undissolved crystals can be easily seen at the bottom. the character of the solution is now observed. if it be colorless or of a very light straw color, and not opalescent, so that it will give a clear transparent liquid on filtration through paper, the volume is made up directly with water to the c.c. mark on the flask. most sugar solutions, however, will require the addition of a clarifying or decolorizing agent in order to render them sufficiently clear and colorless to polarize. in such case, before making up to the mark, a saturated solution of subacetate of lead is added. the quantity of this agent required will vary according to the quality of the sugar; for sugar which has been grained in the strike pan and washed in the centrifugals, from to drops will be required; for sugar grained in the strike pan but not well washed in the centrifugals, that is, sugar intended for refining purposes, from to drops will be required; for sugar not grained in the strike pan, that is, "wagon" or "string sugar," "second sugar," etc., from to c.c. will be required. after adding the solution of subacetate of lead the flask must be gently shaken, so as to mix it with the sugar solution. if the proper amount has been added, the precipitate will usually subside rapidly, but if not, the operator may judge of the completeness of the precipitation by holding the flask above the level of the eye and allowing an additional drop of subacetate of lead to flow down the side of the flask into the solution; if this drop leaves a clear track along the glass through the solution it indicates that the precipitation is complete; if, on the other hand, all traces of the drop are lost on entering the solution, it indicates that an additional small quantity of the subacetate of lead is required. the operator must learn by experience the point where the addition should cease; a decided excess of subacetate of lead solution should never be used. the use of subacetate of lead should, in all cases, be followed by the addition of "alumina cream" (aluminic hydrate suspended in water)[ ] in about double the volume of the subacetate solution used, for the purpose of completing the clarification, precipitating excess of lead, and facilitating filtration. in many cases of high grade sugars, especially beet sugars, the use of alumina alone will be sufficient for clarification without the previous addition of subacetate of lead. [footnote : prepared as follows: shake up powdered commercial alum with water at ordinary temperature until a saturated solution is obtained. set aside a little of the solution, and to the residue add ammonia, little by little, stirring between additions, until the mixture is alkaline to litmus paper. then drop in additions of the portion left aside, until the mixture is just acid to litmus paper. by this procedure a cream of aluminum hydroxide is obtained suspended in a solution of ammonium sulphate, the presence of which is not at all detrimental for sugar work when added after subacetate of lead, the ammonium sulphate precipitating whatever excess of lead may be present.] the solution is now made up to the mark by the addition of distilled water in the following manner. the flask, grasped by the neck between the thumb and finger, is held before the operator in an upright position, so that the mark is at the level of the eye, and distilled water is added drop by drop from a siphon bottle or wash bottle, until the lowest point of the curve or meniscus formed by the surface of the liquid just touches the mark. if bubbles hinder the operation, they may be broken up by adding a single drop of ether, or a spray from an ether atomizer, before making up to the mark. the mouth of the flask is now tightly closed with the thumb, and the contents of the flask are thoroughly mixed by turning and shaking. the entire solution is now poured upon the filter, using for this purpose a funnel large enough to contain all the c.c. at once, and a watch glass is placed over the funnel during filtration to prevent a concentration of the solution by evaporation. the funnel and vessel used to receive the filtrate must be perfectly dry. the first portion of the filtrate, about to c.c., should be rejected entirely, as its concentration may be affected by a previous hygroscopic moisture content of the filter paper. it may also be necessary to return subsequent portions to the filter until the liquid passes through perfectly clear. if a satisfactory clarification has not been obtained, the entire operation must be repeated, since only with solutions that are entirely clear and bright can accurate polarimetric observations be made. when a sufficient quantity of the clear liquid has passed through the filter, the mm. observation tube is filled with it. the mm. tube should never be used except in rare cases, when notwithstanding all the means used to effect the proper decolorization of the solution, it is still too dark to polarize in the mm. tube. in such cases the shorter tube may be used, and its reading multiplied by two. the zero deviation must then be determined and applied to the product. this will give the reading which would have been obtained if a mm. tube could have been used, and it only remains to apply the correction determined by the use of the control plate as previously described. example: solution reads in mm. tube . multiplied by . ---- product . zero reads plus . . ---- solution would read in mm. tube . reading of control plate . sugar value of control plate . ---- instrument too low by . add . to . ---- correct polarization of solution . before filling the tube it must either be thoroughly dried by pushing a plug of filter paper through it, or it must be rinsed several times with the solution itself. the cover glasses must also be clean and dry, and without serious defects or scratches. unnecessary warming of the tube by the hand during filling should be avoided; it is closed at one end with the screw cap and cover glass, and grasped by the other end with the thumb and finger. the solution is poured into it until its curved surface projects slightly above the opening, the air bubbles allowed time to rise, and the cover glass pushed horizontally over the end of the tube in such a manner that the excess of liquid is carried over the side, leaving the cover glass exactly closing the tube with no air bubbles beneath it, and with no portion of the liquid upon its upper surface. if this result is not attained, the operation must be repeated, the cover glass being rubbed clean and dry, and the solution again brought up over the end by adding a few more drops. the cover glass being in position, the tube is closed by screwing on the cap. the greatest care must be observed in screwing down the caps that they do not press too tightly upon the cover glasses; by such pressure the glasses themselves may become optically active, and cause erroneous readings when placed in the instrument. it should therefore be ascertained that the rubber washers are in position over the cover glasses, and the caps should be screwed on lightly. it must also be remembered that a cover glass, once compressed, may part with its acquired optical activity very slowly, and some time must be allowed to elapse before it is used again. the polariscopic reading may now be taken, an observation on the ° control plate having been made immediately before as previously described. then without altering the position of the instrument relative to the light, or changing the character of the latter in any way, the tube filled with the sugar solution is substituted for the control plate. the telescope is adjusted, if necessary, so as to give a sharply defined field, which must appear round and clear. (this condition must be fulfilled before the observation is performed, as it is essential to accuracy.) the milled head is turned until the neutral point is found, and the reading is taken exactly as previously described, the operation repeated five or six times, the average taken with the rejection of aberrant readings, the average figure corrected for the deviation shown by the control observation from the sugar value of the control plate at the temperature of observation as given in the table, and the result taken as the polarization of the sugar. when a series of successive polarizations is made under the same conditions as regards temperature, position of the instrument with relation to the high intensity, of the light, etc., the control observation need not be made before each polarization, one such observation being sufficient for the entire series. the control must be repeated at least once an hour, however, and oftener when the operator has reason to think that any of the factors indicated above have been altered, for any such alteration of conditions may change the zero point of the instrument. in the polarization of the quartz plates, as also in the polarization of very white sugars, difficulty may be experienced in obtaining a complete correspondence of both halves of the field. with a little practice this may be overcome and the neutral point found, but when it cannot, the ordinary telescope of the instrument may be replaced by another, which is furnished with the polariscope and which carries a yellow plate. this removes the difficulty and renders it possible, even for one not well accustomed to the instrument, to set it at the exact point of neutrality. summarized sources of error. the following principal sources of error must be especially guarded against: . drying out of sample during weighing. . excess of subacetate of lead solution in clarification. . incomplete mixing of solution after making up to mark. . imperfect clarification or filtration. . concentration of solution by evaporation during filtration. . undue compression of the cover glass. . alteration of the temperature of room, position of instrument, or intensity of light while the observation or control observation is being performed. . performances of polarization with a cloudy, dim, or not completely round or sharply defined field. in closing this report the members of this commission hereby signify their intention to promote uniformity and accuracy by adopting and using the standards and general plan of procedure recommended in this report in the polarimetric determinations over which, in their respective branches of government work, they have control. * * * * * the grand falls of labrador. hamilton inlet, or ionektoke, as the esquimaus call it, is the outlet to the largest river on the labrador peninsula, and of great importance to commerce, rigolet, the headquarters of the hudson bay company in this region, being situated on its shores. this inlet is the great waterway to central labrador, extending into the interior for nearly miles. this immense basin is undoubtedly of glacial origin, evidences of ice erosion being plainly seen. it is divided into two general basins, connected by the "narrows," a small strait, through which the water rushes with frightful rapidity at each tide. into the head of the inlet flows the hamilton, or grand river, an exploration of which, though attended with the greatest danger and privation, has enticed many men to these barren shores. perhaps the most successful expedition thus far was that of mr. holme, an englishman, who, in the summer of , went as far as lake waminikapon, where, by failure of his provisions, he was obliged to turn back, leaving the main object of the trip, the discovery of the grand falls, wholly unaccomplished. it has been left for bowdoin college to accomplish the work left undone by mr. holme, to do honor to herself and her country by not only discovering, measuring, and photographing the falls, but making known the general features of the inland plateau, the geological structure of the continent, and the course of the river. on sunday, july , a party of the bowdoin expedition, consisting of messrs. cary, cole, young, and smith, equipped with two rushton boats and a complement of provisions and instruments, left the schooner at the head of the inlet for a five weeks' trip into the interior, the ultimate object being the discovery of the grand falls. the mouth of the river, which is about one mile wide, is blockaded by immense sand bars, which have been laid down gradually by the erosive power of the river. these bars extend far out into goose bay, at the head of lake melville, and it is impossible to approach the shores except in a small boat. twenty-five miles up the river are the first falls, a descent of the water of twenty-five feet, forming a beautiful sight. here a cache of provisions was made, large enough to carry the party back to the appointed meeting place at northwest river. the carry around the first falls is about one and a half miles in length, and very difficult on account of the steep sides of the river. from the first falls to gull island lake, forty miles above, the river is alternately quick and dead water. part of it is very heavy rapids, over which it was necessary to track, and in some places to double the crews. each boat had a tow line of fifty feet, and in tracking the end was taken ashore by one of the crew of two, while the boat was kept off the bank by the other man with an oar. at the horseshoe rapids, ten miles above gull island lake, an accident happened which threatened to put a stop to further progress of the expedition. while tracking around a steep point in crossing these rapids the boat which messrs. cary and smith were tracking was overturned, dumping barometer, shotgun, and ax into the river, together with nearly one-half the total amount of provisions. in the swift water of the rapids all these things were irrevocably lost, a very serious loss at this stage in the expedition. on this day so great was the force of the water that only one mile was made, and that only with the greatest difficulty. just above the mouth of the nimpa river, which enters the grand river twenty-five miles above gull island lake, a second cache of provisions was made, holding enough to carry the party to their first cache at the first falls. one of the boats was now found to be leaking badly, and a stop was made to pitch the cracks and repair her, making necessary the loss of a few hours. from nimpa river to the mouni rapids, at the entrance to lake waminikapon, the water was found to be fairly smooth, and good progress was made. the change in the scenery, too, is noticeable, becoming more magnificent and grand. the mountains, which are bolder and more barren, approach much nearer to each other on each side of the river, and at the base of these grim sentinels the river flows silvery and silently. the mouni rapids, through which the water passes from lake waminikapon, presented the next obstacle to further progress, but the swift water here was soon passed, and well repaid the traveler with the sight here presented almost unexpectedly to his view. the lake was entered about o'clock in the afternoon, and, as the narrow entrance was passed, the sun poured its full rich light on rocky mountains stretching as far away as the eye could reach, on each side of the lake, and terminating in rocky cliffs from to feet in perpendicular height, which formed the shores or confines of the lake. across lake waminikapon, which is, more properly speaking, not a lake at all, but rather a widening of the river bed, the progress was very good, the water having no motion to retard the boats, and forty miles were made during the day. here a misfortune, which had been threatening for several days, came upon the party. mr. young's arm was so swollen, from the shoulder to finger tips, that he could scarcely move it, the pain being excessive. it had been brought on doubtless by cold and exposure. seeing that he could be of no further use to the party, it was decided to divide forces, mr. smith returning with the sick man to rigolet for medical assistance. the separation took place august , when the party had been on the river eleven days. the party were very sorry to return at this point, since from the best information which they could get in regard to the distance, the falls were but fifty miles above them. under the circumstances, however, there was no help for it. so smith and young, bidding their friends good fortune, started on their return trip. the mouth of the river was reached in three days, a little less than one-third the time consumed in going up, and that, too, with only one man to handle the boat. on the way down the river another party, composed of messrs. bryant and kenaston of philadelphia, was met, who were on the same business as the bowdoin party, the discovery of the falls. mr. bryant handed to mr. young a twenty-five pound can of flour, which, he said, he had found in the whirlpool below the first falls. it had been in the boat which was overturned in the horseshoe rapids, and had made the journey to the first falls, a distance of over fifty miles, without denting or injuring the can in any way. it was a great relief to the bryant party to learn the cause of the mishap, as they had feared a more serious calamity. after the departure of the other two, messrs. cary and cole encountered much rapid water, so that their progress was necessarily slow. on the third day, when they had proceeded sixty-five miles above lake waminikapon, and had seen no indications of any falls, the rapidity of the current forced them to leave the river and make any further progress on foot. the boat was cached at this point, together with all that was left of provisions and instruments except the compass and food for six days. they left just enough provisions to carry them to their last cache at ninipi river, and hoped, by careful use of the remainder, to find the object of their search. if they had not enough provisions, then they must turn back, leaving reports of falls as destitute of confirmation as ever. the land bordering the river at this point was heavily wooded, and in places where the river shore could not be followed on account of the cliffs, their progress was necessarily slow. finding an elevation of land at no great distance from them, they ascended it for a general survey of the country. far away in the distance could be seen the current of the grand river flowing sluggishly but majestically on its course to the sea. lakes on all sides were visible, most of them probably of glacial origin. descending from this mountain, which the explorers christened mount bowdoin, a course was laid on the river bank, where camp was made that night. being now somewhat weak from hard labor and insufficient food, their progress was slow through the thick wood, but on the next night camp was made on the edge of the plateau or table land of labrador. after proceeding a short distance on the next day, aug. , a loud roar was heard in the distance, and a course was laid for the river at the nearest point. the river at this point, about one mile above the falls, was yards wide, narrowing to fifty yards a short distance below, where great clouds of spray floating in the air warned the weary travelers that their object had been attained. quickly they proceeded to the scene, and a magnificent sight burst upon their view. grand falls, though not approaching the incredible height attributed to it by legendary accounts of the indians, is a grand fall of water. its total descent is accomplished in a series of falls aggregating nearly feet. the greatest perpendicular descent is not over feet. the half dozen falls between this grand descent and the bed of the river on the plateau vary from ten to twenty-five feet, adding to the majesty and grandeur of the scene. it was with great difficulty that the bottom of the falls was reached and a photograph of the scene taken. after leaving the plateau and plunging over the falls, the waters enter an immense cañon or gorge, nearly miles long and yards wide, the perpendicular sides of which rise to a height of from to feet. the sides of this cañon show it to be hollowed out of solid archæan rock. through this cañon the water rushes with terrific rapidity, making passage by boat wholly impossible. many erroneous stories have been told in regard to the height of these falls, all of them greatly exaggerating the descent of the water. the indians of this locality of the tribe of the nascopee or the race of crees have long believed the falls to be haunted by an evil spirit, who punished with death any one who might dare to look upon them. the height of land or plateau which constitutes the interior of the labrador peninsula is from , to , feet above the sea level, fairly heavily wooded with spruce, fir, hackmatack, and birch, and not at all the desolate waste it has been pictured by many writers. the barrenness of labrador is confined to the coast, and one cannot enter the interior in any direction without being struck by the latent possibilities of the peninsula were it not for the abundance of flies and mosquitoes. their greed is insatiable, and at times the two men were weakened from the loss of blood occasioned by these insects. the object of the expedition being attained, the return trip was begun, and the sight of the cached boat and provisions eagerly watched for. on aug. the camp was sighted, but to their horror they saw smoke issuing from the spot. it at once flashed upon their minds what had taken place, and when they arrived they found that their fears had been all too truly realized. charred remains of the boat, a burned octant, and a few unexploded cartridges were all that remained of the meager outfit upon which they depended to take them to the mouth of the river, a distance of over miles. the camp fire, not having been completely extinguished, had burned the boat and destroyed all their provisions. it was truly a hard outlook for them, but no time must be lost if provisions were to be obtained. hastily a raft was constructed, the logs being bound together with spruce roots. in this way, by alternately walking and rafting, the mouth of the river was reached aug. . on the way down the river five rafts had been made and abandoned. the only weapon was a small pocket revolver, and with the products of this weapon, mostly red squirrels and a few fish, they lived until they reached the different caches. many a meal was made of one red squirrel divided between them, and upon such food they were compelled to make the best time possible. on the way up the river the shoes of one of the party had given wholly out, and he was obliged to make a rude pair of slippers from the back of a leather pack. with torn clothes and hungry bodies they presented a hard sight indeed when they joined their friends at rigolet on the st of september. the party composed of messrs. bryant and kenaston was passed by cary and cole while on the way down, but was not seen. probably this occurred on lake waminikapon, the width of the lake preventing one party from seeing the other. it seemed a waste of time and energy that two expeditions in the same summer should be sent upon the same object, but neither party knew of the intention of the other until it was too late to turn back. grand river has long been a highway for the dependents of the hudson bay company. the company formerly had a post on lake waminikapon, and another, called height of land, on the plateau. provisions were carried to these posts, and furs brought from them by way of grand river, the parties proceeding as far as the lake, and then, leaving grand river some distance below the cañon, no longer being able to follow it on account of the swiftness of the water, they carried their canoes across the land to a chain of lakes connecting with the post. this station has been given up many years, and the river is used now chiefly be indians and hunters in the winter. it has long been known that hamilton inlet was of glacial origin, the immense basin hollowed out by this erosive agent being miles in length. how much further this immense valley extended has never been known. mr. cary says that the same basin which forms hamilton inlet and enters lake melville, the two being connected by twelve miles of narrows, extends up the grand river valley as far as gull island lake, the whole forming one grand glacial record. from lake melville to gull island the bed was being gradually filled in by the deposits of the river, but the contour of the basin is the same here as below. the bed of the country here is archæan rock, and many beautiful specimens of labradorite dot the shores. in the distance the grim peaks of the mealy mountains stand out in bold relief against the sky. the country about this interior basin is heavily wooded, and spars of feet can be obtained in generous numbers. were it not for the native inhabitants, mosquitoes, and flies, the interior would present conditions charming enough to tempt any lover of nature. it is the abundance of these invincible foes which make interior life a burden and almost an impossibility. to these inhabitants alone grand falls has ceased to chant its melodious tune. hereafter its melodious ripple will be heard by bowdoin college, which, in the name of its explorers, cary and cole, claims the honor of its discovery.--_new york times_. * * * * * ants. by ruth ward kahn. astronomy has made us all familiar with the conception of the world over our heads. we no longer speculate with epicurus and anaxagoras whether the sun may be as large as a quoit, or even as large as peloponnesus. we are satisfied that the greater and the lesser lights are worlds, some of them greatly exceeding our own in magnitude. in a little poem of dante rossetti's, he describes a mood of violent grief in which, sitting with his head bowed between his knees, he unconsciously eyes the wood spurge growing at his feet, till from those terrible moments he carries away the one trivial fact cut into his brain for all time, that "the wood spurge has a cup of three." in some such mood of troubled thought, flung perhaps full length on the turf, have we not as unconsciously and intently watched a little ant, trudging across our prostrate form, intent upon its glorious polity: a creature to which we, with our great spiritual world of thought and emotion and will, have no existence except as a sudden and inconvenient upheaval of parti-colored earth to be scaled, of unknown geological formation, but wholly worthless as having no bearing upon the one great end of their life--the care of larvæ. if we hold with mr. wallace that the chief difference between man and the lower animals is that of kind and not of degree--that man is possessed of an intelligent will that appoints its own ends, of a conscience that imposes upon him a "categorical imperative," of spiritual faculties that apprehend and worship the invisible--yet we must admit that his lower animal nature, which forms, as it, were, the platform of the spiritual, is built up of lower organisms. if we hold with professor allman that thought, will, and conscience, though only manifesting themselves through the medium of cerebral protoplasm, are not its properties any more than the invisible earth elements which lie beyond the violet are the property of the medium which, by altering their refrangibility, makes them its own--then the study of the exact nature and properties of the transmitting medium is equally necessary. indeed, the whole position can only be finally established of defining experimentally the necessary limitation of the medium, and proving the inefficiency of the lower data to account with the higher. it is these considerations of the wider issues that give such a peculiar interest to the patient observations which have recently been brought to bear upon the habits of the social insects, especially of ants, which, living in communities, present so many of the conditions of human life, and the development of the "tribal self" from these conditions, to which professor clifford attributed the genesis of moral sense. in order to pass in review these interesting observations and bring out their significance, i must go over ground which is doubtless familiar to most of my readers. the winged ants, which often excite surprise, are simply the virgin queens and the males. they are entirely dependent upon the workers, and are reared in the same nest. september is the month usually selected as the marriage season, and in the early twilight of a warm day the air will be dark with the winged lovers. after the wedding trip the female tears off her wings--partly by pulling, but mostly by contortions of her body--for her life under ground would render wings not only unnecessary, but cumbersome; while the male is not exposed to the danger of being eaten by his cannibal spouse, as among spiders, nor to be set upon and assassinated by infuriated spinsters, as among bees, but drags out a precarious existence for a few days, and then either dies or is devoured by insectivorous insects. there is reason to believe that some females are fertilized before leaving the nest. i have observed flights of the common _formica rufa_, in which the females flew away solitary and to great distances before they descended. in such cases it is certain that they were fertilized before their flight. when a fertilized queen starts a colony it proceeds much in this way: when a shaft has been sunk deep enough to insure safety, or a sheltered position secured underneath the trunk of a tree or a stone, the queen in due time deposits her first eggs, which are carefully reared and nourished. the first brood consists wholly of workers, and numbers between twenty-five and forty in some species, but is smaller in others. the mother ant seeks food for herself and her young till the initial brood are matured, when they take up the burden of life, supply the rapidly increasing family with food, as well as the mother ant, enlarge the quarters, share in the necessary duties, and, in short, become the _real_ workers of the nest before they are scarcely out of the shell. the mother ant is seldom allowed to peer beyond her dark quarters, and then only in company with her body guard. she is fed and cared for by the workers, and she in turn assists them in the rearing of the young, and has even been known to give her strength for the extension of the formicary grounds. several queens often exist in one nest, and i have seen workers drag newly fertilized queens into a formicary to enlarge their resources. as needs be, the quantity of eggs laid is very great, for the loss of life in the ranks of the workers is very large; few survive the season of their hatching, although queens have been known to live eight years. (lubbock.) the ant life has four well marked periods: first, the egg; second, the grub or larva; third, the chrysalis or pupa; fourth, the imago, or perfect insect. the eggs are small, ovate, yellowish white objects, which hatch in about fifteen to thirty days. the larvæ are small legless grubs, quite large at the apex of the abdomen and tapering toward the head. both eggs and pupa are incessantly watched and tended, licked and fed, and carried to a place of safety in time of danger. the larvæ are ingeniously sorted as regards age and size, and are never mixed. the larvæ period generally extends through a month, although often much longer, and in most species when the larvæ pass into pupæ they spin a cocoon of white or straw color, looking much like a shining pebble. other larvæ do not spin a cocoon, but spend the pupal state naked. when they mature they are carefully assisted from their shells by the workers, which also assist in unfolding and smoothing out the legs. the whole life of the formicary centers upon the young, which proves they have reached a degree of civilization unknown even in some forms of higher life. it is curious that, notwithstanding the labor of so many excellent observers, and though ants swarm in every field and wood, we should find so much difficulty in the history of these insects, and that so much obscurity should rest upon some of their habits. forel and ebrard, after repeated observations, maintain that in no single instance has an isolated female been known to bring her young to maturity. this is in direct contradiction to lubbock's theory, who repeatedly tried introducing a new fertile queen into another nest of _lasius flavus_, and always with the result that the workers became very excited and killed her, even though in one case the nest was without a queen. of the other kinds, he isolated two pairs of _myrmica ruginodis_, and, though the males died, the queens lived and brought their offspring to perfection; and nearly a year after their captivity, sir john lubbock watched the first young workers carrying the larvæ about, thereby proving the accuracy of huber's statement, with some species at least. in spite of this convincing testimony, lepeletier st. fargeau is of the opinion that the nests originate with a solitary queen, as was first given. the ants indigenous to leadville, besides feeding on small flies, insects, and caterpillars--the carcasses of which they may be seen dragging to their nests--show the greatest avidity for sweet liquids. they are capable of absorbing large quantities, which they disgorge into the mouths of their companions. in winter time, when the ants are nearly torpid and do not require much nourishment, two or three ants told off as foragers are sufficient to provide for the whole nest. we all know how ants keep their herds in the shape of aphides, or ant cows, which supply them with the sweet liquid they exude. i have often observed an ant gently stroking the back of an aphide with its antennæ to coax it to give down its sweet fluid, much in the same way as a dairy maid would induce a cow to give down its milk by a gentle manipulation of its udders. some species, principally the masons and miners, remove their aphides to plants in the immediate vicinity of their nest, or even introduce them into the ant home. in the interior of most nests is also found the small blind beetle (_claviger_) glistening, and of a uniform red, its mouth of so singular a conformation that it is incapable of feeding itself. the ants carefully feed these poor dependent creatures, and in turn lick the sweet liquid which they secrete and exude. these little _coleoptera_ are only found in the nests of some species; when introduced into the nests of others they excite great bewilderment, and, after having been carefully turned over and examined, are killed in a short time as a useless commodity. another active species of _coleoptera_, of the family _staphylini_, is also found in ant nests. i have discovered one in the nest of _formica rufa_ in the jewish cemetery in leadville. furnished with wings, it does not remain in the nest, but is forced to return thither by the strange incapacity to feed itself. like the _claviger_, it repays its kind nurses by the sweet liquid it exudes, and which is retained by a tuft of hair on either side of the abdomen beneath the wings, which the creature lifts in order that the ant may get at its honeyed recompense. such mutual services between creatures in no way allied is a most curious fact in the animal world.--_popular science news._ * * * * * a gem-bearing granite vein in western connecticut. by l.p. gratacap. in the county of litchfield, conn., in the midst of some of the most attractive hill country of that region, a very striking mineral fissure has been opened by mr. s.l. wilson, which, in both its scientific and commercial aspects, is equally important and interesting. it is a broad crevice, widened at the point of excavation into something like a pocket and filled, between its inclosing walls of gneiss, with a granitic mass whose elements have crystallized separately, so that an almost complete mineralogical separation has been effected of quartz, mica, and feldspar, while associated aggregates, as beryl and garnet, have formed under conditions that make them valuable gem fabrics. the vein has a strike south of west and north of east and a distinct dip northwest, by which it is brought below the gneiss rock, which forms an overhanging wall, on the northerly side of the granitic mass, while on the southerly edge the same gneiss rock makes an almost vertical foot wall, and exhibits a sharp surface of demarkation and contact. the rock has been worked as an open cut through short lateral "plunges," or tunnels have been used for purposes of exploration in the upper part of its extent. its greatest width appears to be fifty-one feet, and the present exposure of its length three hundred. it undergoes compression at its upper end, and its complete extinction upon the surface of the country at that point seems probable. at its lower end at the foot of the slope wherein the whole mass appears, it reveals considerable development, and affords further opportunities for examination, and, possibly, profitable investment. it has been formed by a powerful thrust coincident with the crumpling of the entire region, whereby deeply seated beds have become liquefied, and the magma either forced outward through a longitudinal vent or brought to the surface by a process of progressive fusion as the heated complex rose through superincumbent strata dissipated by its entrance and contributing their substance to its contents. the present exposure of the vein has been produced by denudation, as the coarsely crystalline and dismembered condition of the granite, with its large individuals of garnet and beryl, and the dense, glassy texture of the latter, indicate a process of slow cooling and complete separation, and for this result the congealing magma must necessarily have been sealed in by strata through which its heat was disseminated slowly. for upon the most cursory inspection of the vein, the eye is arrested at once by the large masses of crystalline orthoclase, the heavy beds of a gray, brecciated quartz and the zones and columns of large leaved mica. it was to secure the latter that mr. wilson first exploited this locality, and only latterly have the more precious contents of the vein imparted to it a new and more significant character. the mica, called by mr. atwood, the superintendent of the work, "book mica," occurs in thick crystals, ranged heterogeneously together in stringers and "chimneys," and brilliantly reflecting the sunlight from their diversely commingled laminæ. this mica yields stove sheets of about two to three by four or five inches, and is of an excellent, transparent quality. it seems to be a true muscovite, and is seldom marred by magnetic markings or crystalline inclusions that would interfere with its industrial use. seams of decomposition occur, and a yellowish scaly product, composed of hydrated mica flakes, fills them. the mica does not everywhere present this coarsely crystalline appearance, but in flexures and lines of union with the quartz and orthoclase is degraded to a mica schist upon whose surfaces appear uranates of lime and copper (autunite and torbernite), and in which are inclosed garnet crystals of considerable size and beauty. the enormous masses of clean feldspar made partially "graphic" by quartz inclosures are a conspicuous feature of the mine. in one part of the mine, wooden props support an overhanging ledge almost entirely composed of feldspar, which underneath passes into the gray brecciated quartz, which again grades into a white, more compact quartz rock. it is in this gray brecciated quartz that the beryls are found. these beautiful stones vary extremely in quality and color. many of the large crystals are opaque, extensively fractured, and irregular in grain, but are found to inclose, especially at their centers, cores of gem-making material. the colors of the beryls grade from an almost colorless mineral (goshenite) though faintly green, with blue reflections, yellowish green of a peculiar oily liquidity (davidsonite), to honey yellows which form the so-called "golden beryls" of the trade, and which have a considerable value. these stones have a hardness of , and when cut display much brilliancy. many assume the true aquamarine tints, and others seem to be almost identical with the "diamond of the rhine," which as early as the end of the fifteenth century was used as a "fraudulent substitute for the true diamond" (king). few, very few, belong to the blue grades, and the best of these cannot compare with those from royalston, mass. those of amber and honey shades are beautiful objects, and under artificial light have a fascination far exceeding the olivine or chrysoberyl. these are not as frequent as the paler varieties, but when found excite the admiration of visitor and expert. it seems hardly probable that any true emeralds will be uncovered and the yellow beryls may not increase in number. their use in the arts will be improved by combining them with other stones and by preparing the larger specimens for single stone rings. very effective combinations of the aquamarine and blue species with the yellow may be recommended. tourmaline appears in some quantity, forming almost a schist at some points, but no specimens of any value have been extracted, the color being uniformly black. the garnets are large trapezohedral-faced crystals of an intense color, but penetrated with rifts and flaws. many, no doubt, will afford serviceable gem material, but their resources have not yet been tested by the lapidary. while granite considered as a building stone presents a complex of quartz, mica, and feldspar so confusedly intercrystallized as to make a homogeneous composite, in the present mass, like the larger and similar developments in north carolina, these elements have excluded each other in their crystallization, and are found as three separate groups only sparingly intermingled. the proportions of the constituent minerals which form granite, according to prof. phillips, are twenty parts of potash feldspar (orthoclase), five parts of quartz, and two parts of potash mica (muscovite), and a survey of mr. wilson's quarry exhibits these approximate relations with surprising force. there can be but little doubt that this vein is a capital example of hydrothermal fusion, whereby in original gneissic strata, at a moderate temperature and considerable depth, through the action of contained water, with the physical accompaniment of plication, a solution of the country rock has been accomplished. and the cooling and recrystallization has gone on so slowly that the elements of granite have preserved a physical isolation, while the associated silicates formed in the midst of this magma have attained a supremely close and compact texture, owing to the favorable conditions of slow growth giving them gem consistencies. the further development of the vein may reveal interesting facts, and especially the following downward of the rock mass, which we suspect will contract into a narrower vein. at present the order of crystallization and separation of the mineralogical units seems to have been feldspar, mica, garnet, beryl, quartz. in the artificial preparation of crystals it is invariably found that perfect and symmetrical crystals, and crystals of large size, are produced by slow, undisturbed cooling of solutions; the quiet accretion permits complete molecular freedom and the crystal is built up with precision. nor is this all. in mixtures of chemical compounds it is presumable that the separate factors will disengage themselves from each other more and more completely, and form in purer masses as the congelation is slowly carried on. a sort of concretionary affinity comes into play, and the different chemical units congregate together. at least such has been the case in the granitic magma of which mr. wilson now possesses the solidified results. the feldspar, the quartz, the mica, have approximately excluded each other, and appear side by side in unmixed purity. and does it not seem probable that this deliberate process of solidification has produced in the beryls, found in the center of the vein at the points of slowest radiation, the glassy gem texture which now makes them available for the purposes of art and decoration? * * * * * the study of mankind. professor max muller, who presided over the anthropological section of the british association, said that if one tried to recall what anthropology was in , and then considered what it was now, its progress seemed most marvelous. these last fifty years had been an age of discovery in africa, central asia, america, polynesia, and australia, such as could hardly be matched in any previous century. but what seemed to him even more important than the mere increase of material was the new spirit in which anthropology had been studied during the last generation. he did not depreciate the labors of so-called dilettanti, who were after all lovers of knowledge, and in a study such as that of anthropology, the labors of these volunteers, or franc-tireurs, had often proved most valuable. but the study of man in every part of the world had ceased to be a subject for curiosity only. it had been raised to the dignity and also the responsibility of a real science, and was now guided by principles as strict and rigorous as any other science. many theories which were very popular fifty years ago were now completely exploded; nay, some of the very principles by which the science was then guided had been discarded. among all serious students, whether physiologists or philologists, it was by this time recognized that the divorce between ethnology and philology, granted if only for incompatibility of temper, had been productive of nothing but good. classification. instead of attempting to classify mankind as a whole, students were now engaged in classifying skulls, hair, teeth, and skin. many solid results had been secured by these special researches; but as yet, no two classifications, based on these characteristics, had been made to run parallel. the most natural classification was, no doubt, that according to the color of the skin. this gave us a black, a brown, a yellow, a red, and a white race, with several subdivisions. this classification had often been despised as unscientific; but might still turn out far more valuable than at present supposed. the next classification was that by the color of the eyes, as black, brown, hazel, gray, and blue. this subject had also attracted much attention of late, and, within certain limits, the results have proved very valuable. the most favorite classification, however, had always been that according to the skulls. the skull, as the shell of the brain, had by many students been supposed to betray something of the spiritual essence of man; and who could doubt that the general features of the skull, if taken in large averages, did correspond to the general features of human character? we had only to look around to see men with heads like a cannon ball and others with heads like a hawk. this distinction had formed the foundation for a more scientific classification into brachycephalic, dolichocephalic, and mesocephalic skulls. if we examined any large collection of skulls we had not much difficulty in arranging them under these three classes; but if, after we had done this, we looked at the nationality of each skull, we found the most hopeless confusion. pruner vey, as peschel told us in his "volkerkunde," had observed brachycephalic and dolichocephalic skulls in children born of the same mother; and if we consider how many women had been carried away into captivity by mongolians in their inroads into china, india, and germany, we could not feel surprised if we found some long heads among the round heads of those central asiatic hordes. differences in skulls. only we must not adopt the easy expedient of certain anthropologists who, when they found dolichocephalic and brachycephalic skulls in the same tomb, at once jump to the conclusion that they must have belonged to two different races. when, for instance, two dolichocephalic and three brachycephalic skulls were discovered in the same tomb at alexanderpol, we were told at once that this proved nothing as to the simultaneous occurrence of different skulls in the same family; nay, that it proved the very contrary of what it might seem to prove. it was clear, we were assured, that the two dolichocephalic skulls belonged to aryan chiefs and the three brachycephalic skulls to their non-aryan slaves, who were killed and buried with their masters, according to a custom well known to herodotus. this sounded very learned, but was it really quite straightforward? besides the general division of skulls into dolichocephalic, brachycephalic, and mesocephalic, other divisions had been undertaken, according to the height of the skull, and again according to the maxillary and the facial angles. this latter division gave us orthognatic, prognathic, and mesognathic skulls. lastly, according to the peculiar character of the hair, we might distinguish two great divisions, the people with woolly hair (ulotriches) and people with smooth hair (lissotriches). the former were subdivided into lophocomi, people with tufts of hair, and eriocomi, or people with fleecy hair. the latter were divided into euthycomi, straight haired, and euplocomi, wavy haired. it had been shown that these peculiarities of the hair depended on the peculiar form of the hair tubes, which in cross sections were found to be either round or elongated in different ways. all these classifications, to which several more might be added, those according to the orbits of the eyes, the outlines of the nose, and the width of the pelvis, were by themselves extremely useful. but few of them only, if any, ran strictly parallel. now let them consider whether there could be any organic connection between the shape of the skull, the facial angle, the conformation of the hair, or the color of the skin on one side, and what we called the great families of language on the other. connection of language and physical conformation. that we spoke at all might rightly be called a work of nature, _opera naturale_, as dante said long ago; but that we spoke thus or thus, _cosi o cosi_, that, as the same dante said, depended on our pleasure--that was our work. to imagine, therefore, that as a matter of necessity, or as a matter of fact, dolichocephalic skulls had anything to do with aryan, mesophalic with semitic, or brachycephalic with turanian speech, was nothing but the wildest random thought. it could convey no rational meaning whatever; we might as well say that all painters were dolichocephalic, and all musicians brachycephalic, or that all lophocomic tribes worked in gold, and all lisocomic tribes in silver. if anything must be ascribed to prehistoric times, surely the differentiation of the human skull, the human hair and the human skin would have to be ascribed to that distant period. no one, he believed, had ever maintained that a mesocephalic skull was split or differentiated into a dolichocephalic and a brachycephalic variety in the bright sunshine of history. nevertheless, he had felt for years that knowledge of languages must be considered in future as a _sine qua non_ for every anthropologist. how few of the books in which we trusted with regard to the characteristic peculiarities of savage races had been written by men who had lived among them for ten or twenty years, and who had learned their languages till they could speak them as well as the natives themselves. it was no excuse to say that any traveler who had eyes to see and ears to hear could form a correct estimate of the doings and sayings of savage tribes. travelers' impressions. it was not so, as anthropologists knew from sad experience. suppose a traveler came to a camp where he saw thousands of men and women dancing round the image of a young bull. suppose that the dancers were all stark naked, that after a time they began to fight, and that at the end of their orgies there were three thousand corpses lying about weltering in their blood. would not a casual traveler have described such savages as worse than the negroes of dahomey? yet these savages were really the jews, the chosen people of god. the image was the golden calf, the priest was aaron, and the chief who ordered the massacre was moses. we might read the d chapter of exodus in a very different sense. a traveler who could have conversed with aaron and moses might have understood the causes of the revolt and the necessity of the massacre. but without this power of interrogation and mutual explanation, no travelers, however graphic and amusing their stories might be, could be trusted; no statements of theirs could be used by the anthropologist for truly scientific purposes. if anthropology was to maintain its high position as a real science, its alliance with linguistic studies could not be too close. its weakest points had always been those where it trusted to the statements of authorities ignorant of language and of the science of language. its greatest triumphs had been achieved by men such as dr. hahn, bishops callaway and colenso, dr. w. gill and last, not least, mr. man, who had combined the minute accuracy of the scholar with the comprehensive grasp of the anthropologist, and were thus enabled to use the key of language to unlock the perplexities of savage customs, savage laws and legends, and, particularly, of savage religions and mythologies. if this alliance between anthropology and philology became real, then, and then only, might we hope to see bunsen's prophecy fulfilled, that anthropology would become the highest branch of that science for which the british association was instituted. * * * * * a new catalogue of valuable papers contained in scientific american supplement during the past ten years, sent _free of charge_ to any address. munn & co., broadway, new york. * * * * * the scientific american architects and builders edition. $ . a year. single copies, cts. this is a special edition of the scientific american, issued monthly--on the first day of the month. each number contains about forty large quarto pages, equal to about two hundred ordinary book pages, forming, practically, a large and splendid magazine of architecture, richly adorned with _elegant plates in colors_ and with fine engravings, illustrating the most interesting examples of modern architectural construction and allied subjects. a special feature is the presentation in each number of a variety of the latest and best plans for private residences, city 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continue to examine improvements, and to act as solicitors of patents for inventors. in this line of business they have had _forty-five years' experience_, and now have _unequaled facilities_ for the preparation of patent drawings, specifications, and the prosecution of applications for patents in the united states, canada, and foreign countries. messrs. munn & co. also attend to the preparation of caveats, copyrights for books, labels, reissues, assignments, and reports on infringements of patents. all business intrusted to them is done with special care and promptness, on very reasonable terms. a pamphlet sent free of charge, on application, containing full information about patents and how to procure them; directions concerning labels, copyrights, designs, patents, appeals, reissues, infringements, assignments, rejected cases. hints on the sale of patents, etc. we also send, _free of charge_, a synopsis of foreign patent laws, showing the cost and method of securing patents in all the principal countries of the world. munn & co., solicitors of patents, broadway, new york. branch offices.--nos. and f street, pacific building, near th street, washington, d.c. note: project gutenberg also has an html version of this file which includes the original illustrations. see -h.htm or -h.zip: (http://www.gutenberg.net/dirs/ / / / / / -h/ -h.htm) or (http://www.gutenberg.net/dirs/ / / / / / -h.zip) illustrated science for boys and girls. [illustration: from dr. franklin's broom-corn seed. see page .] boston: d. lothrop & company, franklin street. copyright, , by d. lothrop & company. table of contents. page how newspapers are made. umbrellas. paul and the comb-makers. in the gas-works. racing a thunder-storm. august's "'speriment." the birds of winter. something about light-houses. "buy a broom! buy a broom!" talking by signals. jennie finds out how dishes are made. archery for boys. dolly's shoes. a glimpse of some montana beavers. how logs go to mill. list of illustrations. page frontispiece the n. y. tribune building at night. a contributor to the waste-paper basket. office of the editor-in-chief. regular contributors how some of the news is gathered type-setter's case in pi. type-setters' room. taking "proofs." in the stereotypers' room. finishing the plate. printing presses of the past and present a news-dealer. a bad morning for the news-boys. "any answers come for me?" the first umbrella. what jonas saw adown the future. lord of the twenty-four umbrellas. a "duck's back" umbrella. an umbrella handle au naturel. cutting the covers. finishing the handle. sewing "pudding-bag" seams. completing the umbrella master paul did not feel happy. my lady's toilet. the new circle comb ancient or modern--which? "in some remote corner of spain." a retort. kitty in the gas-works. the metre. the gasometre. inflating the "buffalo." a plucky dog. our balloon camp. the professor's dilemma. the wreck of the "buffalo." the incubator. how the chicken is packed. how the shell is cracked. the artificial mother. the chickadee. the black snow-bird. the snow bunting. the brown creeper. nuthatches. the downy woodpecker. fourth order light-house. a modern light-house light-house on mt. desert. light-house at "the thimble shoal" first class light-ship. the blind broom-maker of barnstable. a gay cavalcade. the comedy of brooms. up in the attic. plant the broom! the tragedy of brooms. in obedience to the signals. the potter's wheel. the kiln and saggers. mould for a cup. handle mould. making a sugar-bowl. rest for flat dishes. the target. dolly's shoes a maine wood-chopper. a river-driver. "the liberated logs came sailing along." through the sluice. illustrated science for boys and girls. how newspapers are made. we will suppose that it is a great newspaper, in a great city, printing daily , , or more, copies. here it is, with wide columns, with small, compact type, with very little space wasted in head lines, eight large pages of it, something like , words printed upon it, and sold for four cents-- , words for a cent. it is a great institution--a power greater than a hundred banking-houses, than a hundred politicians, than a hundred clergymen. it collects and scatters news; it instructs and entertains with valuable and sprightly articles; it forms and concentrates public opinion; it in one way or another, brings its influence to bear upon millions of people, in its own, and other lands. who would not like to know something about it? and there is tom, first of all, who declares that he is going to be a business man, and who already has a bank-book with a good many dollars entered on its credit side--there is tom, i say, asking first of all: "how much does it cost? and where does the money come from? and is it a paying concern?" tom shall not have his questions expressly answered; for it isn't exactly his business; but here are some points from which he may figure: "_how much does it cost?_" well, there is the publishing department, with an eminent business man at its head, with two or three good business men for his assistants, and with several excellent clerks and other employès. then there is the editor-in-chief, and the managing editor, and the city editor, and a corps of editors of different departments, besides reporters--thirty or forty men in all, each with some special literary gift. then there are thirty or forty men setting type; a half-dozen proof-readers; a half-dozen stereotypers; the engineer and foreman and assistants below stairs, who do the printing; and several men employed in the mailing department. then there are tons and tons of paper to be bought each week; ink, new type, heavy bills for postage; many hundreds of dollars a week for telegraphic dispatches; and the interest on the money invested in an expensive building; expensive machinery, and an expensive stock of printers' materials--nothing being said of the pay of correspondents of the paper at the state capitol, at washington, at london, at paris, etc. tom is enough of a business man, already, i know, to figure up the weekly expenses of such an establishment at several thousands of dollars--a good many hundreds at each issue of the paper. [illustration: the n. y. tribune building at night.] "_and where does the money come from?_" partly from the sale of papers. only four cents apiece, and only a part of that goes to the paper; but, then, , times, say two-and-a-half cents, is $ , which it must be confessed, is quite a respectable sum for quarter-dimes to pile up in a single day. but the greater part of the money comes from advertisements. nearly half of the paper is taken up with them. if you take a half-dozen lines to the advertising clerk, he will charge you two or three dollars; and there are several hundred times as much as your small advertisement in each paper. so you may guess what an income the advertising yields. and the larger, the more popular, and the more widely read the paper, the better will be the prices which advertisers will pay, and the more will be the advertisements. and so the publisher tries to sell as many papers as he can, partly because of the money which he gets for them, but more, because the more he sells the more advertising will he get, and the better rates will he charge for it. so, tom, if you ever become the publisher of a newspaper, you must set your heart on getting an editor who will make a paper that will sell--whatever else he does or does _not_ do. "_and is it a paying concern?_" well, i don't think the editors think they get very large pay, nor the correspondents, nor the reporters, nor the printers, nor the pressmen. they work incessantly; it is an intense sort of work; the hours are long and late; the chances of premature death are multiplied. i think they will all say: "we aren't in this business for the money that is in it; we are in it for the influence of it, for the art of it, for the love of it; but then, we are very glad to get our checks all the same." as to whether the paper pays the men who own it--which was tom's question: i think that that "depends" a great deal on the state of trade, on the state of politics, and on the degree to which the paper will, or will not, scruple to do mean things. a great many papers would pay better, if they were meaner. it would be a great deal easier to make a good paper, if you did not have to sell it. when, then, jonathan shall have become a minister, he doesn't want to bear down too hard on a "venal press" in his fast day and thanksgiving sermons. perhaps, by that time, tom will be able to explain why. "_how, now, is this paper made?_" "but," interrupts jonathan, "before they make it, i should like to know where they get the , words to put into it; i have been cudgeling my brains for now two weeks to get words enough to fill a four page composition--say words, _coarse_." the words which are put into it are, besides the advertisements, chiefly: . news; . letters and articles on various subjects; . editorial articles, reviews, and notes; . odds and ends. the "_letters and articles on various subjects_" come from all sorts of people: some from great writers who get large pay for even a brief communication; some from paid correspondents in various parts of the world; some from all sorts of people who wish to proclaim to the world some grievance of theirs, or to enlighten the world with some brilliant idea of theirs--which generally loses its luster the day the article is printed. a large proportion of letters and articles from this last class of people get sold for waste-paper before the printer sees them. this is one considerable source of income to the paper, of which i neglected to tell tom. [illustration: a contributor to the waste-paper basket.] as for the "_odds and ends_"--extracts from other papers, jokes, and various other scraps tucked in here and there--a man with shears and paste-pot has a good deal to do with the making of them. if you should see him at work, you would want to laugh at him--as if he were, for all the world, only little nell cutting and pasting from old papers, a "frieze" for her doll's house. but when his "odds and ends," tastefully scattered here and there through the paper, come under the reader's eye, they make, i am bound to say, a great deal of very hearty laughter which is not that laughter of ridicule which the sight of him at his work might excite. [illustration: office of the editor-in-chief.] about the "_news_," i must speak more fully. the "_editorial articles, reviews, and notes_," we shall happen upon when we visit the office. a part of the news comes by telegraph from all parts of the world. some of it is telegraphed to the paper by its correspondents, and the editors call it "special," because it is especially to them. perhaps there is something in it which none of the other papers have yet heard of. but the general telegraphic news, from the old-world and the new, is gathered up by the "associated press." that is to say, the leading papers form an association and appoint men to send them news from the chief points in america and in europe. these representatives of the associated press are very enterprising, and they do not allow much news of importance to escape them. the salaries of these men, and the cost of the telegraphic dispatches, are divided up among the papers of the association, so that the expense to each paper is comparatively small. owing to this association of papers, hundreds of papers throughout the country publish a great deal of matter on the same day which is word-for-word alike. two devices in this matter of associated press dispatches save so much labor, that i think you will like me to describe them. one is this: suppose there are a dozen papers in the same city which are entitled to the associated press dispatches. instead of making a dozen separate copies, which might vary through mistakes, one writing answers for all the dozen. first, a sheet of prepared tissue paper is laid down, then a sheet of a black, smutty sort of paper, then two sheets of tissue paper, then a sheet of black paper, and so on, until as many sheets of tissue paper have been piled up, as there are copies wanted. upon the top sheet of paper, the message is written, not with pen, or pencil, but with a hard bone point, which presses so hard that the massive layers of tissue paper take off from the black paper a black line wherever the bone point has pressed. thus a dozen pages are written with one writing, and off they go, just alike, to the several newspaper offices. the printers call this queer, tissue-paper copy--"manifold." [illustration: regular contributors] the other device is a telegraphic one. suppose the associated press agent in new york is sending a dispatch to the boston papers. there are papers belonging to the association at, say, new haven, hartford, springfield and worcester. instead of sending a message to each of these points, also, the message goes to boston, and operators at new haven, hartford, springfield, and worcester, _listen to it as it goes through_, and copy it off. thus one operator at new york is able to talk to perhaps a score of papers, in various parts of new england, or elsewhere, at once. but in a large city there is a great deal of city and suburban news. take for example, new york; and there is that great city, and brooklyn, and jersey city, and hoboken, and newark, and elizabeth, to be looked after, as well as many large villages near at hand. and there is great competition between the papers, which shall get the most, the exactest, and the freshest, news. consequently, each day, a leading new york paper will publish a page or more of local news. the city editor has charge of collecting this news. he has, perhaps, twenty or twenty-five men to help him--some in town, and others in the suburbs. his plan for news collecting will be something like this: he will have his secretary keep two great journals, with a page in each devoted to each day. one of these, the "blotter," will be to write things in which are going to happen. everything that is going to happen to-morrow, the next day, the next, and so on, the secretary will make a memorandum of or paste a paragraph in about upon the page for the day on which the event will happen. whatever he, or the city editor, hears or reads of, that is going to happen, they thus put down in advance, until by and by, the book gets fairly fat and stout with slips which have been pasted in. but, this morning, the city editor wants to lay out to-day's work. so his secretary turns to the "blotter," at to-day's page, and copies from it into to-day's page in the second book all the things to happen to-day--a dozen, or twenty, or thirty--a ship to be launched, a race to come off, a law-case to be opened, a criminal to be executed, such and such important meetings to be held, and so on. by this plan, nothing escapes the eye of the city editor who, at the side of each thing to happen, writes the name of the reporter whom he wishes to have write the event up. this second book is called the "assignment book;" and, when it is made out, the reporters come in, find their orders upon it, and go out for their day's work, returning again at evening for any new assignments. besides this, they, and the city editor, keep sharp ears and eyes for anything new; and so, amongst them, the city and suburbs are ransacked for every item of news of any importance. the city editor is a sort of general. he keeps a close eye on his men. he finds out what they can best do, and sets them at that. he gives the good workers better and better work; the poor ones he gradually works out of the office. those who make bad mistakes, or fail to get the news, which some other paper gets, are frequently "suspended," or else discharged out-and-out. failing to get news which other papers get, is called being "beaten," and no reporter can expect to get badly "beaten" many times without losing his position. [illustration: how some of the news is gathered] and now, tom, and jonathan, and even little nell, we'll all be magicians to-night, like the father of miranda, in "the tempest," and transport ourselves in an instant right to one of those great newspaper offices. [illustration: type-setter's case in pi.] it is six o'clock. the streets are dark. the gaslights are glaring from hundreds of lamp-posts. do you see the highest stories of all those buildings brilliant with lights? those are the type-setters' rooms of as many great newspapers. in a twinkling we are several stories up toward the top of one of these buildings. these are the editorial rooms. we'll make ourselves invisible, so that they'll not suspect our presence, and will do to-night just as they always do. [illustration: type-setters' room.] up over our heads, in the room of the type-setters, are a hundred columns, or more, of articles already set--enough to make two or three newspapers. the foreman of the type-setters makes copies of these on narrow strips of paper with a hand-press, and sends them down to the editor-in-chief. these copies on narrow strips of paper, are called "proofs," because, when they are read over, the person reading them can see if the type has been set correctly--can prove the correctness or incorrectness of the type-setting. [illustration: taking "proofs."] the editor-in-chief runs rapidly through these proofs, and marks, against here and there one, "_must_," which means that it "must" be published in to-morrow's paper. against other articles he marks, "_desirable_," which means that the articles are "desirable" to be used, if there is room for them. many of the articles he makes no mark against, because they can wait, perhaps a week, or a month. by having a great many articles in type all the time, they never lack--jonathan will be glad to know--for something to put into the paper. jonathan might well take the hint, and write his compositions well in advance. against some of the articles, the word "_reference_" is written, which indicates that when the article is published an editorial article or note with "reference" to it must also be published. before the editor-in-chief is through, perhaps he marks against one or two articles the word "_kill_," which means that the article is, after all, not wanted in the paper, and that the type of it may be taken apart--the type-setters say "distributed"--without being printed. [illustration: in the stereotypers' room.] when the editor-in-chief is through with the proofs, perhaps he has a consultation with the managing editor--the first editor in authority after him--about some plans for to-night's paper, or for to-morrow, or for next week. perhaps, then, he summons in the night editor. the night editor is the man who stays until almost morning, who overlooks everything that goes into the paper, and who puts everything in according to the orders of the editor-in-chief, or of the managing editor. well, he tells the night editor how he wants to-morrow's paper made, what articles to make the longest, and what ones to put in the most important places in the paper. then, perhaps, the city editor comes knocking at the door, and enters, and he and the editor-in-chief talk over some stirring piece of city news, and decide what to say in the editorial columns about it. after the editor-in-chief has had these consultations, perhaps he begins to dictate to his secretary letters to various persons, the secretary taking them down in short-hand, as fast as he can talk, and afterwards copying them out and sending them off. that is the sort of letter-writing which would suit little nell--just to say off the letter, and not to have to write it--which, in her case, means "printing" it in great, toilsome capitals. after dictating perhaps a dozen letters, it may be that the editor-in-chief dictates in the same manner, an editorial article, or some other matter which he wishes to have appear in the paper. thus he spends several hours--perhaps the whole night--in seeing people, giving directions, dictating letters and articles, laying out new plans, and exercising a general headship over all things. turning, now, from his room, we observe in the great room of the editors, a half dozen men or more seated at their several desks--the managing editor and the night editor about their duties; two or three men looking over telegraph messages and getting them ready for the type-setters; two or three men writing editorial, and other articles. from this room we turn to the great room of the city department. there is the city editor, in his little, partitioned-off room, writing an editorial, we will suppose, on the annual report of the city treasurer, which has to-day been given to the public. at desks, about the great room, a half-dozen reporters are writing up the news which they have been appointed to collect; and another, and another, comes in every little while. [illustration: finishing the plate.] over there, is the little, partitioned-off room for the assistant city editor. it is this man's duty, with his assistant, to prepare for the type-setters all the articles which come from the city department. there are stacks and stacks of them. each reporter thinks his subject is the most important, and writes it up fully; and, when it is all together, perhaps there is a third or a half more than there is room in the paper to print. so the assistant city editor, and his assistant, who come to the office at about five o'clock in the afternoon, read it all over carefully, correct it, cut out that which it is not best to use, group all the news of the same sort so that it may come under one general head, put on suitable titles, decide what sort of type to put it in, etc.,--a good night's work for both of them. they also write little introductions to the general subjects, and so harmonize and modify the work of twenty or twenty-five reporters, as to make it read almost as if it were written by one man, with one end in view. the editors of the general news have to do much the same thing by the letters of correspondents, and by the telegraphic dispatches. while this sort of work goes on, hour after hour, with many merry laughs and many good jokes interspersed to make the time fly the swifter, we will wander about the establishment. here, in the top story of the building, is the room of the type-setters. every few minutes, from down-stairs in the counting room, comes a package of advertisements to be put into type; and from the editorial rooms a package of news and general articles for the same purpose. they do not trouble to send them up by a messenger. a tube, with wind blown through it very fast, brings up every little while a little leathern bag, in which are the advertisements or the articles--the "copy" as the type-setters call it. in this room are thirty or forty type-setters. each one of them has his number. when the copy comes up, a man takes it and cuts it up into little bits, as much as will make, say, a dozen lines in the paper, and numbers the bits--"one," "two," etc., to the end of the article. type-setter after type-setter comes and takes one of these little bits, and in a few moments sets the type for it, and lays it down in a long trough, with the number of the bit of copy laid by the side of it. we will suppose that an article has been cut up into twenty bits. twenty men will each in a few moments be setting one of these bits, and, in a few minutes more they will come and lay down the type and the number of the bit in the long trough, in just the right order of the number of the bits--"one," "two," etc. then all the type will be slid together, and a long article will thus be set in a few minutes, which it would take one or two men several hours to set. it is by this means that long articles can in so short a time be put into type. each man who takes a bit, has to make his last line fill out to the end of the line; and, because there are sometimes not words enough, so that he has to fill out with some extra spaces between the words, you may often see in any large daily paper every two inches, or so, a widely spaced line or two showing how the type-setter had to fill out his bit with spaces--only he would call the bit, a "take." [illustration: printing presses of the past and present] i said that each type-setter has his number. we will suppose that this man, next to us, is number "twenty-five." then he is provided with a great many pieces of metal, just the width of a column, with his number made on them--thus: "twenty-five." every time he sets a new bit of copy, he puts one of these "twenty-fives" at the top; and when all the bits of type in the long trough are slid together the type is broken up every two inches or so, with "twenty-five," "thirty-seven," "two," "eleven," and so on, at the top of the bits which the men, whose numbers these are, have set. when a proof of the article is taken, these several numbers appear; and, if there are mistakes, it appears from these numbers, what type-setters made them, and they have to correct them. also, of each article, a single "proof" is taken on colored paper. these colored paper "proofs" are cut up the next day, and all the pieces marked "twenty-five," "thirty-seven," and so on, go to the men who have these numbers, and when pasted together show how much type, number "twenty-five," "thirty-seven," and so on, are to be paid for setting--for the type-setters are paid according to the amount of type which they set. [illustration: add yellow fever eight new cases of yellow fever--four whites and four colored--were reported to the board of health to-day. but one death has occurred since last night, archie p. kehoe, son of the late captain p. m. kehoe, who died beyond the city limits. thirty-four in addition to the new cases reported to the board of health, the following persons were stricken with the fever to-day: lyttleton penn; p. s. simonds, an ex-policeman; jessie anderson, mrs. john bierman, and r. t. dabney, the signal service officer, who it was thought had a mild attack of the fever about three weeks ago. five miss louise bedford died last night of yellow fever at barclay station, tenn. fifteen nurses were assigned to duty to-day by the howards. the weather is clear and pleasant. twenty three fac-simile of "proof" showing "takes."] as fast as the proofs are taken they go into the room of the proof-readers to be corrected. the bits of copy are pasted together again, and one man holds the copy while another reads the proof aloud. the man holding the copy notices any points in which the proof does not read like the copy, and tells the man who is reading it. the man reading it corrects the variations from copy, and corrects all the other mistakes which he can discover, and then the type-setters have to change the type so as to make it right. there the proof readers sit hard at work, reading incredibly fast, and making rapid and accurate corrections; then the "copy" is locked up, and no one can get at it, except the managing editor or editor-in-chief gives an order to see it. this precaution is taken, in order to make certain who is responsible for any mistakes which appear in the paper--the editors, or the type-setters. by this time it is nearly midnight, and the editors, type-setters, etc., take their lunches. they either go out to restaurants for them, or have them sent in--hot coffee, sandwiches, fruit, etc.--a good meal for which they are all glad to stop. and now the foreman of the type-setters sends to the night editor that matter enough is in type to begin the "make-up"--that is, to put together the first pages of the paper. there the beautiful type stands, in long troughs, all corrected now, the great numbers of the type-setters removed from between the bits of type--the whole ready to be arranged into page after page of the paper. so the night editor makes a list of the articles which he wants on the page which is to be made up; the foreman puts them in in the order which the night editor indicates; the completed page is wedged securely into an iron frame, and then is ready to be stereotyped. [illustration: a news-dealer.] the room of the stereotypers is off by itself. there is a furnace in it, and a great caldron of melted type metal. they take the page of the paper which has just been made up; put it on a hot steam chest; spat down upon the type some thick pulpy paper soaked so as to make it fit around the type; spread plaster of paris on the back, so as to keep the pulpy paper in shape; and put the whole under the press which more perfectly squeezes the pulpy paper down upon the type, and causes it to take a more perfect impression of the type. the heat of the steam chest warms the type, and quickly dries the pulpy paper and the plaster of paris. then the pulpy paper is taken off, and curved with just such a curve as the cylinders of the printing-press have, and melted type metal is poured over it, which cools in a moment; when, lo, there is a curving plate of type-metal just like the type! the whole process of making this plate takes only a few minutes. they use such plates as these, rather than type, in printing the great papers chiefly for reasons like these: . because plates save the wear of type; . because they are easier handled; . because they can be made curving, to fit the cylinders of the printing presses as it would be difficult to arrange the type; . because several plates can be made from the same type, and hence several presses can be put at work at the same time printing the same paper; . because, if anything needs to be added to the paper, after the presses have begun running, the type being left up-stairs can be changed and new plates made, so that the presses need stop only a minute for the new plates to be put in--which is a great saving of time. but, coming down into the editorial rooms again--business tom, and thoughtful jonathan, and sleepy little nell--all is excitement. telegrams have just come in telling of the wreck of an ocean steamer, and men are just being dispatched to the steamer's office to learn all the particulars possible, and to get, if it may be, a list of the passengers and crew. and now, just in the midst of this, a fire-alarm strikes, and in a few moments the streets are as light as day with the flames of a burning warehouse in the heart of the business part of the city. more men are sent off to that; and, what with the fire and the wreck, every reporter, every copy-editor, every type-setter and proof-reader are put to their hardest work until the last minute before the last page of the paper must be sent down to the press-rooms. then, just at the last, perhaps the best writer in the office dashes off a "leader" on the wreck sending a few lines at a time to the type-setters--a leader which, though thought out, written, set, corrected, and stereotyped in forty minutes, by reason of its clearness, its wisdom, and its brilliancy, is copied far and wide, and leads the public generally to decide where to fix the blame, and how to avoid a like accident again. there is the work of the "_editorial articles, reviews, and notes_"--to comment on events which happen, and to influence the minds of the public as the editorial management of the paper regards to be wise. there is all sorts of this editorial writing--fun, politics, science, literature, religion--and he who says, with his pen, the say of such a newspaper, wields an influence which no mind can measure. [illustration: a bad morning for the news-boys.] well, the fire, and the wreck, have thoroughly awakened even little nell. and so down, down we go, far under ground, to the press-rooms. there the noise is deafening. two or three presses are at work. at one end of the press is a great roll of paper as big as a hogshead and a mile or more long. this immense roll of paper is unwinding very fast, and going in at one end of the machine; while at the other end, faster than you can count, are coming out finished papers--the papers printed on both sides, cut up, folded, and counted, without the touch of a hand--a perfect marvel and miracle of human ingenuity. the sight is a sight to remember for a lifetime. upon what one here sees, hinges very much of the thinking of a metropolis and of a land. and now, here come the mailing clerks, to get their papers to send off--with great accuracy and speed of directing and packing--by the first mails which leave the city within an hour and a half, at five and six o'clock in the morning. and after them come the newsboys, each for his bundle; and soon the frosty morning air in the gray dawn is alive with the shouting of the latest news in this and a dozen other papers. [illustration: "any answers come for me?"] this, i am sure, is too fast a world even for business tom: so let us "spirit" ourselves back to our beds in the quiet, slow-moving, earnest country--tom and jonathan and little nell and i--home, and to sleep--and don't wake us till dinner-time! umbrellas. [illustration: the first umbrella.] about one hundred and thirty years ago, an englishman named jonas hanway, who had been a great traveller, went out for a walk in the city of london, carrying an umbrella over his head. [illustration: what jonas saw adown the future.] every time he went out for a walk, if it rained or if the sun shone hotly, he carried this umbrella, and all along the streets, wherever he appeared, men and boys hooted and laughed; while women and girls, in doorways and windows, giggled and stared at the strange sight, for this jonas hanway was the first man to commonly carry an umbrella in the city of london, and everybody, but himself, thought it was a most ridiculous thing to do. but he seems to have been a man of strength and courage, and determined not to give up his umbrella even if all london made fun of him. perhaps, in imagination, he saw adown the future, millions of umbrellas--umbrellas enough to shelter the whole island of england from rain. whether he did foresee the innumerable posterity of his umbrella or not, the "millions" of umbrellas have actually come to pass. but jonas hanway was by no means the first man in the world to carry an umbrella. as i have already mentioned, he had travelled a great deal, and had seen umbrellas in china, japan, in india and africa, where they had been in use for so many hundreds of years that nobody knows when the first one was made. so long ago as nineveh existed in its splendor, umbrellas were used, as they are yet to be found sculptured on the ruins of that magnificent capital of assyria, as well as on the monuments of egypt which are very, very old; and your ancient history will tell you that the city of nineveh was founded not long after the flood. perhaps it was that great rain, of forty days and forty nights, that put in the minds of noah, or some of his sons, the idea to build an umbrella! although here in america the umbrella means nothing but an umbrella, it is quite different in some of the far eastern countries. in some parts of asia and africa no one but a royal personage is allowed to carry an umbrella. in siam it is a mark of rank. the king's umbrella is composed of one umbrella above another, a series of circles, while that of a nobleman consists of but one circle. in burmah it is much the same as in siam while the burmese king has an umbrella-title that is very comical: "lord of the twenty-four umbrellas." the reason why the people of london ridiculed jonas hanway was because at that time it was considered only proper that an umbrella should be carried by a woman, and for a man to make use of one was very much as if he had worn a petticoat. there is in one of the harleian mss. a curious picture showing an anglo-saxon gentleman walking out, with his servant behind him carrying an umbrella; the drawing was probably made not far from five hundred years ago, when the umbrella was first introduced into england. whether this gentleman and his servant created as much merriment as mr. hanway did, i do not know; neither can i tell you why men from that time on did not continue to use the umbrella. if i were to make a "guess" about it, i should say that they thought it would not be "proper," for it was considered an unmanly thing to carry one until a hundred years ago when the people of this country first began to use them. and it was not until twenty years later, say in the year , that the "yankees" began to make their own umbrellas. but since that time there have been umbrellas and umbrellas! [illustration: lord of the twenty-four umbrellas.] the word umbrella comes from the latin word _umbra_, which means a "little shade;" but the name, most probably, was introduced into the english language from the italian word _ombrella_. parasol means "to ward off the sun," and another very pretty name, not much used by americans, for a small parasol, is "parasolette." it would be impossible for me to tell you how many umbrellas are made every year in this country. a gentleman connected with a large umbrella manufactory in the city of philadelphia gave me, as his estimate, , , . this would allow an umbrella to about one person in six, according to the census computation which places the population of the united states at , , of people. and one umbrella for every six persons is certainly not a very generous distribution. added to the number made in this country, are about one-half million which are imported, chiefly from france and england. you who have read "robinson crusoe," remember how he made his umbrella and covered it with skins, and that is probably the most curious umbrella you can anywhere read about. then there have been umbrellas covered with large feathers that would shed rain like a "duck's back," and umbrellas with coverings of oil-cloth, of straw, of paper, of woollen stuffs, until now, nearly all umbrellas are covered either with silk, gingham, or alpaca. and this brings us to the manufacture of umbrellas in philadelphia, where there are more made than in any other city in america. if you will take an umbrella in your hand and examine it, you will see that there are many more different things used in making it than you at first supposed. first, there are the "stick," made of wood, "ribs," "stretchers" and "springs" of steel; the "runner," "runner notch," the "ferule," "cap," "bands" and "tips" of brass or nickel; then there are the covering, the runner "guard" which is of silk or leather, the "inside cap," the oftentimes fancy handle, which may be of ivory, bone, horn, walrus tusk, or even mother-of-pearl, or some kind of metal, and, if you will look sharply, you will find a rivet put in deftly here and there. for the "sticks" a great variety of wood is used; although all the wood must be hard, firm, tough, and capable of receiving both polish and staining. the cheaper sticks are sawed out of plank, chiefly, of maple and iron wood. they are then "turned" (that is made round), polished and stained. the "natural sticks," not very long ago, were all imported from england. but that has been changed, and we now send england a part of our own supply, which consists principally of hawthorne and huckleberry, which come from new york and new jersey, and of oak, ash, hickory, and wild cherry. [illustration: a "duck's back" umbrella.] if you were to see these sticks, often crooked and gnarled, with a piece of the root left on, you would think they would make very shabby sticks for umbrellas. but they are sent to a factory where they are steamed and straitened, and then to a carver, who cuts the gnarled root-end into the image of a dog or horse's head, or any one of the thousand and one designs that you may see, many of which are exceedingly ugly. the artist has kindly made a picture for you of a "natural" stick just as it is brought from the ground where it grows, and, then again, the same stick after it has been prepared for the umbrella. of the imported "natural" sticks, the principal are olive, ebony, furze, snakewood, pimento, cinnamon, partridge, and bamboo. perhaps you do not understand that a "natural" stick is one that has been a young tree, having grown to be just large enough for an umbrella stick, when it was pulled up, root and all, or with at least a part of the root. if, when you buy an umbrella that has the stick bent into a deep curve at the bottom for the handle, you may feel quite sure that it is of partridge wood, which does not grow large enough to furnish a knob for a handle, but, when steamed, admits of being bent. the "runner," "ferule," "cap," "band," etc., form what is called umbrella furniture and for these articles there is a special manufactory. another manufactory cuts and grooves wire of steel into the "ribs" and "stretchers." formerly ribs were made out of cane or whalebone; but these materials are now seldom used. when the steel is grooved, it is called a "paragon" frame, which is the lightest and best made. it was invented by an englishman named fox, seventeen or eighteen years ago. the latest improvement in the manufacture of "ribs" is to give them an inward curve at the bottom, so that they will fit snugly around the stick, and which dispenses with the "tip cup,"--a cup-shaped piece of metal that closed over the tips. [illustration: an umbrella handle _au naturel_] of course we should all like to feel that we americans have wit enough to make everything used in making an umbrella. and so we have in a way; but it must be confessed that most of the silk used for umbrella covers, is brought from france. perhaps if the cheney brothers who live at south manchester in connecticut, and manufacture such elegant silk for ladies' dresses, and such lovely scarfs and cravats for children, were to try and make umbrella silk, we would soon be able to say to the looms of france, "no more umbrella silk for america, thank you; we are able to supply our own!" [illustration: cutting the covers.] but the "yankees" do make all their umbrella gingham, which is very nice. and one gingham factory that i have heard about has learned how to dye gingham such a _fast_ black, that no amount of rain or sun changes the color. the gingham is woven into various widths to suit umbrella frames of different size, and along each edge of the fabric a border is formed of large cords. as to alpaca, a dye-house is being built, not _more_ than a "thousand miles" from philadelphia on the plan of english dye-houses, so that our home-made alpacas may be dyed as good and durable a black as the gingham receives; for although nobody minds carrying an _old_ umbrella, nobody likes to carry a faded one. although there are umbrellas of blue, green and buff, the favorite hue seems to be black. and now that we have all the materials together to make an umbrella, let us go into a manufactory and see exactly how all the pieces are put together. first, here is the stick, which must be "mounted." by that you must understand that there are two springs to be put in, the ferule put on the top end, and if the handle is of other material than the stick, that must be put on. the ugliest of all the work is the cutting of the slots in which the springs are put. these are first cut by a machine; but if the man who operates it is not careful, he will get some of his fingers cut off. but after the slot-cutting machine does its work, there is yet something to be done by another man with a knife before the spring can be put in. after the springs are set, the ferule is put on, and when natural sticks are used, as all are of different sizes, it requires considerable time and care to find a ferule to fit the stick, as well as in whittling off the end of the stick to suit the ferule. and before going any farther you will notice that all the counters in the various work-rooms are carpeted. the carpet prevents the polished sticks from being scratched, and the dust from sticking to the umbrella goods. [illustration: finishing the handle.] after the handle is put on the stick and a band put on for finish or ornament, the stick goes to the frame-maker, who fastens the stretchers to the ribs, strings the top end of the ribs on a wire which is fitted into the "runner notch;" then he strings the lower ends of the "stretchers" on a wire and fastens it in the "runner," and then when both "runners" are securely fixed the umbrella is ready for the cover. as this is a very important part of the umbrella, several men and women are employed in making it. in the room where the covers are cut, you will at first notice a great number of v shaped things hanging against the wall on either side of the long room. these letter vs are usually made of wood, tipped all around with brass or some other fine metal, and are of a great variety of sizes. they are the umbrella cover patterns, as you soon make out. to begin with, the cutter lays his silk or gingham very smoothly out on a long counter, folding it back and forth until the fabric lies eight or sixteen times in thickness, the layers being several yards in length. (but i must go back a little and tell you that both edges of the silk, or whatever the cover is to be, has been hemmed by a woman, on a sewing machine before it is spread out on the counter). well, when the cutter finds that he has the silk smoothly arranged, with the edges even, he lays on his pattern, and with a sharp knife quickly draws it along two sides of it, and in a twinkling you see the pieces for perhaps two umbrellas cut out; this is so when the silk, or material, is sixteen layers thick and the umbrella cover is to have but eight pieces. after the cover is cut, each piece is carefully examined by a woman to see that there are no holes nor defects in it, for one bad piece would spoil a whole umbrella. then a man takes the pieces and stretches the cut edges. this stretching must be so skilfully done that the whole length of the edge be evenly stretched. this stretching is necessary in order to secure a good fit on the frame. after this the pieces go to the sewing-room, where they are sewed together by a woman, on a sewing-machine, in what is called a "pudding-bag" seam. the sewing-machine woman must have the machine-tension just right or the thread of the seam will break when the cover is stretched over the frame. [illustration: sewing "pudding-bag" seams.] the next step in the work is to fasten the cover to the frame, which is done by a woman. after the cover is fastened at the top and bottom, she half hoists the umbrella, and has a small tool which she uses to keep the umbrella in that position, then she fastens the seams to the ribs; and a quick workwoman will do all this in five minutes, as well as sew on the tie, which has been made by another pair of hands. then the cap is put on and the umbrella is completed. but before it is sent to the salesroom, a woman smooths the edge of the umbrella all around with a warm flat-iron. then another woman holds it up to a window where there is a strong light, and hunts for holes in it. if it is found to be perfect the cover is neatly arranged about the stick, the tie wrapped about it and fastened, and the finished umbrella goes to market for a buyer. after the stick is mounted, how long, think you does it take to make an umbrella? well, my dears--it takes only fifteen minutes! so you see that in the making of so simple an every-day article as an umbrella, that you carry on a rainy day to school, a great many people are employed; and to keep the world supplied with umbrellas thousands and thousands of men and women are kept busy, and in this way they earn money to buy bread and shoes and fire and frocks for the dear little folks at home, who in turn may some day become umbrella makers themselves. [illustration: completing the umbrella] paul and the comb-makers. little paul perkins--master paul his uncle called him--did not feel happy. but for the fact that he was a guest at his uncle's home he might have made an unpleasant exhibition of his unhappiness; but he was a well-bred city boy, of which fact he was somewhat proud, and so his impatience was vented in snapping off the teeth of his pocket-combs, as he sat by the window and looked out into the rain. it was the rain which caused his discontent. only the day before his father, going from new york to boston on business, had left paul at his uncle's, some distance from the "hub," to await his return. it being the lad's first visit, mr. sanford had arranged a very full programme for the next day, including a trip in the woods, fishing, a picnic, and in fact quite enough to cover an ordinary week of leisure. over and over it had been discussed, the hours for each feature apportioned, and through the night paul had lived the programme over in his half-waking dreams. [illustration: master paul did not feel happy.] and now that the eventful morning had come, it brought a drizzling, disagreeable storm, so that mr. sanford, as he met his nephew, was constrained to admit that he did not know what they should find to supply the place of the spoiled programme. "and my little nephew is so disappointed that he has ruined his pretty comb, into the bargain," said the uncle. "i was--was trying to see what it was made of," paul stammered, thrusting the handful of teeth into his coat pocket. "i don't see how combs are made. could you make one, uncle?" "i never made one," mr. sanford replied, "but i have seen very many made. there is a comb-shop not more than a half-mile away, and it is quite a curiosity to see how they make the great horns, rough and ugly as they are, into all sorts of dainty combs and knicknacks." "what kind of horns, uncle?" "horns from all parts of the country, paul. this shop alone uses nearly a million horns a year, and they come in car-loads from canada, from the great west, from texas, from south america, and from the cattle-yards about boston and other eastern cities." "you don't mean the horns of common cattle?" "yes, paul; all kinds of horns are used, though some are much tougher and better than others. the cattle raised in the eastern, middle and western states furnish the best horns, and there is the curious difference that the horns of six cows are worth no more than those of a single ox. many millions of horn combs are made every year in massachusetts; perhaps more than in all the rest of the country. if you like we will go down after breakfast and have a look at the comb-makers." paul was pleased with the idea, though he would much rather have passed the day as at first proposed. he was not at all sorry that he had broken up his comb, and even went so far as to cut up the back with his knife, wondering all the while how the smooth, flat, semi-transparent comb had been produced from a rough, round, opaque horn. by and by a mail stage came rattling along, without any passengers, and mr. sanford took his nephew aboard. they stopped before a low, straggling pile of buildings, located upon both sides of a sluggish looking race-way which supplied the water power, covered passage-ways connecting different portions of the works. "presently, just over this knoll," said his uncle, "you will see a big pile of horns, as they are unloaded from the cars." [illustration: my lady's toilet.] they moved around the knoll, and there lay a monstrous pile of horns thrown indiscriminately together. "really there are not so many as we should think," said mr. sanford, as paul expressed his astonishment. "that is only a small portion of the stock of this shop. i will show you a good many more." he led the way to a group of semi-detached buildings in rear of the principal works, and there paul saw great bins of horns, the different sizes and varieties carefully assorted, the total number so vast that the immense pile in the open yard began to look small in contrast. at one of the bins a boy was loading a wheelbarrow, and when he pushed his load along a plank track through one of the passage-ways mr. sanford and his nephew followed. as the passage opened into another building, the barrow was reversed and its load deposited in a receptacle a few feet lower. in this room only a single man was employed, and the peculiar character of his work at once attracted the attention of paul. in a small frame before him was suspended a very savage-looking circular saw, running at a high rate of speed. the operator caught one of the great horns by its tip, gave it a turn through the air before his eyes, seized it in both hands and applied it to the saw. with a sharp hiss the keen teeth severed the solid tip from the body of the horn, and another movement trimmed away the thin, imperfect parts about the base. the latter fell into a pile of refuse at the foot of the frame, the tip was cast into a box with others; the horn, if large, was divided into two or more sections, a longitudinal slit sawn in one side, and the sections thrown into a box. [illustration: the new circle comb] "this man," said mr. sanford, "receives large pay and many privileges, on account of the danger and unpleasant nature of his task. he has worked at this saw for about forty years, and in that time has handled, according to his record, some twenty-five millions of horns, or over two thousand for every working day. he has scarcely a whole finger or thumb upon either hand--many of them are entirely gone; but most of these were lost during his apprenticeship. the least carelessness was rewarded by the loss of a finger, for the saw cannot be protected with guards, as in lumber-cutting." paul watched the skilful man with the closest interest, shuddering to see how near his hands passed and repassed to the merciless saw-teeth as he sent a ceaseless shower of parts of horns rattling into their respective boxes. before he left the spot paul took a pencil and made an estimate. "why, uncle," he said, "to cut so many as that, he must saw over three horns every minute for ten hours a day. i wouldn't think he could handle them so fast." then, as he saw how rapidly one horn after another was finished, he drew forth his little watch and found that the rugged old sawyer finished a horn every ten seconds with perfect ease. "would you like to learn this trade?" the old fellow asked. he held up his hands with the stumps of fingers and thumbs outspread; but paul only laughed and followed his uncle. they watched a boy wheeling a barrow-load of the horns as they came from the saw, and beheld them placed in enormous revolving cylinders, through which a stream of water was running, where they remained until pretty thoroughly washed. being removed from these, they were plunged into boilers ranged along one side of the building, filled with hot water. "here they are heated," said mr. sanford, "to clear them from any adhering matter that the cold water does not remove, and partially softened, ready for the next operation." [illustration: ancient or modern--which?] from the hot water the horns were changed to a series of similar caldrons at the other side of the room, filled with boiling oil. paul noticed that when the workmen lifted the horns from these vats their appearance was greatly changed, being much less opaque, and considerably plastic, opening readily at the longitudinal cut made by the saw. as the horns were taken from the oil they were flattened by unrolling, and placed between strong iron clamps which were firmly screwed together, and put upon long tables in regular order. "now i begin to see how it is done," paul said, though he was thinking all the time of questions that he would ask his uncle when there were no workmen by to overhear. "the oil softens the horn," said mr. sanford, "and by placing it in this firm pressure and allowing it to remain till it becomes fixed, the whole structure is so much changed that it never rolls again. some combs, you will notice, are of a whitish, opaque color, like the natural horn, while others have a smooth appearance, are of amber color, and almost transparent. the former are pressed between cold irons and placed in cold water, while the others are hot-pressed, it being 'cooked' in a few minutes. these plates of horn may be colored; and there are a great many 'tortoise-shell' combs and other goods sold which are only horn with a bit of color sprinkled upon it. "the solid tips of the horns, and all the pieces that are worth anything cut off in making the combs, are made up into horn jewelry, chains, cigar-holders, knife-handles, buttons, and toys of various kinds. these trinkets are generally colored more or less, and many a fashionable belle, i suppose, would be surprised to know the amount of money paid for odd bits of horn under higher sounding names. but the horn is tough and serviceable, at any rate, and that is more than can be said of many of the cheats we meet with in life." the next room, in contrast with all they had passed through previously, was neat and had no repulsive odors. here the sheets of horn as they came from the presses were first cut by delicate circular saws into blanks of the exact size for the kind of combs to be made, after which they were run through a planer, which gave them the proper thickness. "what do you mean by 'blanks'?" paul asked, as his uncle used the term. "you can look in the dictionary to find its exact meaning," was the answer. "but you will see what it is in practice at this machine." [illustration: "in some remote corner of spain."] they stepped to another part of the room; and here paul saw the "blanks" placed in the cutting-machine standing over a hot furnace, where, after being softened by the heat, they were slowly moved along, while a pair of thin chisels danced up and down, cutting through the centre of the blank at each stroke. when it had passed completely through, an assistant took the perforated blank and pulled it carefully apart, showing two combs, with the teeth interlaced. after separation they were again placed together to harden under pressure, when the final operations consisted of bevelling the teeth on wheels covered with sand-paper, rounding the backs, rounding and pointing the teeth; after which came the polishing, papering and putting in boxes. "i suppose they go all over the country," said paul as he glanced into the shipping-room. "much further than that," was the reply. "we never know how far they go; for the wholesale dealers, to whom the combs are shipped from the manufactory, send them into all the odd corners of the earth. every little dealer must sell combs, and in the very nature of the business they frequently pass through a great many hands before reaching the user, so at the last price is many times what the makers received for them. i suppose it often happens that horns which have been sent thousands of miles to work up are returned to the very regions from which they came, in some other form, increased very many fold in value by their long journey. or a horn may come from the remoter parts of south america to be wrought here in massachusetts, and then be shipped from point to point till it reaches some remote corner of africa, spain, or siberia, as an article of barter. and even different parts of the same horn may be at the same moment decking the person of a new york dandy and unsnarling the tangled locks of a russian tchuktch." while paul was watching the deft fingers of the girls who filled the boxes and affixed the labels, his uncle stepped through a door communicating with the office, and soon returned with three elegant pocket-combs. "one of these," he said, "represents a horn which came from _pampas_ of buenos ayres; this one, in the original, dashed over the boundless plains of texas; and here is another, toughened by the hot, short summers and long, bitter winters of canada. take them with you in memory of this cheerless rainy day." paul could not help a little sigh as he thought again of the pleasures he had enjoyed in anticipation; but still he answered bravely, "thank you; never mind the rain, dear uncle. all the new york boys go off in the woods when they get away from home; but not many of them ever heard how combs are made, and i don't suppose a quarter of them even know what they are made of. i can tell them a thing or two when i get home." in the gas-works. philip and kitty were curled up together on the lounge in the library, reading aldrich's "story of a bad boy." it was fast growing dark in the corner where they were, for the sun had gone down some time before, but they were all absorbed in tom bailey's theatricals, and did not notice how heavy the shadows were getting around them. papa came in by-and-by. "why, little folks, you'll spoil your eyes reading here; i'd better light the gas for you," and he took out a match from the box on the mantle. "o, let me, please," cried philip, jumping up and running to the burner. so he took the match, and climbed up in a chair with it. scr-a-tch! and the new-lit jet gave a glorified glare that illuminated everything in the room, from the japanese vase on the corner bracket to the pattern of the rug before the open fire. but as philip turned it off a little it grew quieter, and finally settled down into a steady, respectable flame. philip always begged to light the gas. it had not been long introduced in the little town where he lived, and the children thought it a very fine thing to have it brought into the house, and secretly pitied the boys and girls whose fathers had only kerosene lamps. "why can't you blow out gas, just as you do a kerosene light?" asked kitty, presently, leaving the bad boy on the lounge, and watching the bright little crescent under the glass shade. "because," explained papa, "unless you shut it off by turning the little screw in the pipe, the gas will keep pouring out into the room all the time, and if it isn't disposed of by being burned up, it will mix with the air and make it poisonous to breathe. a man at the hotel here, a few nights ago, blew out the gas because he did not know any better, and was almost suffocated before he realized the trouble and opened his window." "and where does the gas come from in the first place?" pursued kitty. "why, from the gas-works, of course," said philip in a very superior way, for he was a year the elder of the two. "that brick building over by miller's hill--don't you know--that we pass in going to aunt hester's." "i know that as well as you do, philip lawrence," said kitty with some dignity. "what i wanted to know was what it's made out of. what is it, papa?" "out of coal," said papa. "they put the coal in ovens and heat it till the gas it contains is separated from the other parts of the coal, and driven off by itself. then it is purified and made ready for use." "out of coal? how funny! i wish i could see all about it," said philip, looking more interested. "and so do i wish i could," added kitty. "i don't see why it cannot be done," said papa. "if you really care to see it, and won't mind a few bad smells, i will ask mr. carter to-morrow morning, when he can take you around and explain things." the next day when mr. carter was asked about it, he said, "o, come in any day you like. about three in the afternoon would be a good time, because we are always newly-filling the retorts then." this sounded very nice and imposing to the children, and at three the next afternoon they started out with papa. the gas-house certainly did smell very badly as they drew near it, and dainty kitty sniffed in considerable disgust. philip suggested that perhaps she had better not go in after all; he didn't believe girls ever did go into such places. and upon that kitty valiantly declared she did not mind it a bit, and sternly set her face straight. [illustration: a retort.] mr. carter met them at the door. "you are just in time to see the retorts opened," said he, and led the way directly into a large and very dingy room, along one side of which was built out a sort of huge iron cupboard with several little iron doors. the upper ones were closed tight, but some of the lower ones were open a crack, and a very bright fire could be seen inside. everything around was dirty and gloomy, and these gleams of fire from the little iron doors made the place look weird and ghostly. long iron pipes reached from each of the upper doors up to one very large horizontal pipe or cylinder near the ceiling overhead. this cylinder ran the whole length of the room, and, at its farther end, joined another iron pipe which passed through the wall. "those are the furnace-doors down below," said mr. carter to the children. "what you see burning inside of them is coke. coke is what is left of the coal after we have taken the gas and tar out of it. the upper doors open into the retorts, or ovens, that we fill every five hours with the coal from which we want to get gas. each retort holds about two hundred pounds, and from that amount we get a thousand cubic feet of gas." "is it just common coal;" asked kitty, "like what people burn in stoves?" "not exactly. it is a softer kind, containing more of a substance called hydrogen than the sorts that are generally used for fuel. several different varieties are used: 'cherry,' 'cannel,' 'splint,' and so on, and they come from mines in different parts of england and scotland, chiefly. glasgow, coventry and newcastle send us a great deal." philip started as if a bright idea had struck him. "is that what people mean when you're doing something there's no need of, and they say 'you're carrying coals to newcastle?'" "yes. you see such an enterprise would be absurd. just notice the man yonder with the long iron rod! he is going to open one of the retorts, take out the old coal--only it is now coke--and put in a fresh supply." a workman in a grimy, leather apron loosened one of the retort doors, and held up a little torch. immediately a great sheet of flame burst out, and then disappeared. he took the door quite off, and there was a long, narrow oven with an arched top, containing a huge bed of red-hot coals. "what a splendid place to pop corn!" exclaimed kitty. papa laughed. "you would find it warm work," said he, "unless you'd a very long handle to your corn-popper." and kitty thought so too, as she went nearer the fiery furnace. "you see," said mr. carter, "these red-hot coals have been changed a great deal by the heat. they have given up all their gas and tar, and are themselves no longer coal, but _coke_. we shovel out this coke and use it as fuel in the furnaces down below to help heat up the next lot. then new coal is put into the retorts, and they are closed up with iron plates, like that one lying ready on the ground." "it's all muddy 'round the edge," observed kitty. "yes, that paste of clay is to make it air-tight. the heat hardens the clay very quickly, so all the little cracks around the edge are plastered up. when the coal is shut up in the ovens, or retorts, the heat, as i just told you, divides it up into the different substances of which it is made; that is, into the coke which you have seen, a black, sticky liquid called tar, the illuminating gas, and more or less ammonia, sulphur, and other things that must be got rid of. almost all these things are saved and used for one purpose or another, though they may be of no use to us here. if we have more coke than we ourselves need it is sold for fuel. the coal-tar goes for roofing and making sidewalks, or sometimes (though you wouldn't think it possible, as you look at the sticky, bad-smelling, black stuff) in the manufacture of the most lovely dyes, like that which colored miss kitty's pink ribbon. the ammonia is used for medicine and all sorts of scientific preparations, in bleaching cloth, and in the printing of calicoes and cambrics." "when the materials of the coal are separated as i told you in the retorts, most of the tar remains behind, and is drawn off; but some gets up the pipes. that large, horizontal cylinder is always nearly half full of it. the gas, which is very light, you know, rises through the upper pipes leading from the retorts, and bubbles up through the tar in the bottom of the cylinder. then it passes along the farther end of the cylinder, and into the condensing pipes." he opened a door, and they went through into the next room. here the large pipe which came through the wall of the room they had just left, led to a number of clusters of smaller pipes that were jointed and doubled back and forth upon each other, cob-house fashion. "when the gas goes through these pipes," said mr. carter, "it gets pretty well cooled down, for the pipes are kept cold by having so great an amount of surface exposed to draughts of air around them. and when the gas is cooled the impurities are cooled too, so that many of them take a liquid form and can be drawn off." the next room they entered had a row of great, square chests on each side, as they walked through. "these are the purifiers," explained mr. carter again. "they are boxes with a great many fan-like shelves inside, projecting out in all directions, and covered thickly with a paste made of lime." "lime like what the masons used when they plastered the new kitchen?" asked philip. "about the same thing. the boxes are made air-tight, and the gas enters the first box at one of the lower corners. then before it can get through the connecting-pipe into the next box, it has to wind its way around among these plates coated with lime. this lime takes up the sulphur and other things that we do not want in the gas, and so by the time it gets through all the boxes it is quite pure and fit to use." then the party all went into the room where the gas was measured. it was a little office with a queer piece of furniture in it; something that looked like a very large drum-shaped clock, with several different dials or faces. this, mr. carter said, was the metre or measurer, and by looking at the dials it could be told exactly how much gas was being made every day. [illustration: kitty in the gas-works.] "as soon as the gas gets through the purifiers," said he, "it comes, by an iron pipe, in here, and is made to pass through and give an account of itself before any of it is used. and now i suppose you would like to know how it does report its own amount, wouldn't you?" [illustration: the metre.] philip and kitty both were sure they did want to know, so he sketched a little plan of the metre on a piece of paper, and then went on to explain it: "this shows how the metre would look if you could cut it through in the middle. the large drum-shaped box a. a. is hollow, and filled a little more than half way up with water. inside it is a smaller hollow drum, b. b. so arranged as to turn easily from right to left, on the horizontal axis c. this axis is a hollow pipe by which the gas comes from the purifiers to enter the several chambers of the metre in turn, through small openings called valves. the partitions p. p. p. p. divide the drum b. b. into--let us say--four chambers, , , , , all of the same size, and capable of holding a certain known amount of air or gas. the chamber is now filled with gas, with water, and and partly with gas and partly with water. the valves in the pipe c are so arranged that the gas will next pour into the chamber . this it does with such force as to completely fill it, lifting it quite out of the water and into the place that had occupied before. then as is driven over to the place which had occupied, the gas with which it was filled passes out by another pipe and off to the large reservoir you will see by and by, its place being filled with water. at the same time is driven around to the place of , and to that of . the water always keeps the same level, and simply waits for the chambers to come round and down to be filled. "next, , being in the place of , receives its charge of gas from the entrance pipe, is in turn lifted up into the central position, and sends all the other chambers around one step further. and when the drum gets completely around once, so that the chambers stand in the same places as at first, you know each chamber must have been once filled with gas and then emptied of it. if then we know that each chamber will hold, say two and a half cubic feet of gas, we are sure that every time the drum has turned fully around it has received and sent off four times two and a half feet, or ten feet in all. now we connect the axis c with a train of wheel-work, something like that in a clock, and this wheel-work moves the pointers on the dials in front, so that as the gas in passing in and out of the chambers turns the drum on the axis, it turns the dial pointers also. "the right hand dial marks up to one hundred. while its pointer is passing completely around once, the pointer on the next dial (which marks up to one thousand) is moving a short space and preserving the record of that one hundred; and then the first pointer begins over again. the two pointers act together just like the minute and hour hands on a clock. then the next dial marks up to ten thousand, and acts in turn like an hour-hand to the thousands' dial as a minute-hand, and so on. you see each dial has its denominations, 'thousands,' 'hundred thousands,' or whatever it may be, printed plainly below it. and now, when we want to read off the dials, we begin at the left, taking in each case the last number a pointer _has passed_, and read towards the right, just as you have learned to do with any numbers in your 'eaton's arithmetic.' there is one thing more to remember, however; the number you read means not simply so many cubic feet of gas but so many hundred cubic feet." philip and kitty immediately set to work to read the dials on the office metre, and found that they were not now so very mysterious. "but how do you know how much people use?" asked philip. "there is something like this metre, only smaller, down cellar at home, and a man came and looked at it the other day, to see how much gas had been burned in the house he said, when i asked him what he was going to do." "the metre you have at home works in the same way as this," said mr. carter, "and the dial-plates are read in the same way. but the gas that your little metre registers is only that which you take from the main supply-pipe, to light your parlors and bed-rooms. "when a stream of gas from the main enters the house, it has to pass through the metre the very first thing, before any of it is used; and each little metre keeps as strict an account of what passes through from the main to the burners, as the large one here in the office does of that which passes from the purifiers to the reservoir. but there is this difference between the two: the gas keeps pouring through the office metre as long as we keep making it in the retorts, but it passes through your metre at home only just as long as you keep drawing it off at the burners. so if we find by looking at the metre that feet have passed through during a given time, we send in our bill to your papa for that amount, knowing it must have been burned in the house. "but most likely the metre doesn't say anything directly about . it says, perhaps, . 'how can that be?' you would think. 'we haven't burned so much as that,' and you haven't--during this one quarter. but after the metre had been inspected at the end of the last quarter, the pointers did not go back to the beginning of the dials and start anew; they kept right on from the place where they were, so that is the amount you paid for last time and the amount you want to pay for this time, lumped together. now this is what we do. we turn to our books and see how much you were charged with last time, and subtracting that record from the present record leaves the amount you have used since the last time of payment. "then suppose another case. your metre registers only as far as , . at the end of the last quarter it marked ; now it records but . how would you explain that, master philip?" philip looked puzzled a moment, and then said, "i should think it must have finished out the hundred thousand and begun over again." "exactly. and to find the amount for this quarter you would add together the remainder of the hundred thousand ( ) and the , and get , the real record. but i guess you've had arithmetic enough for the present, so we'll go out now and see the gasometer, or gas reservoir." they all went out of doors then, papa, mr. carter, philip and kitty, across a narrow court-yard. there was a huge, round box, or drum, with sides as high as those of the carriage-house at home, but with no opening anywhere, "like a great giant's bandbox," thought kitty. four stout posts, much taller still than the "bandbox" itself, were set at equal distances around it, and their extremities were joined by stout beams which passed across over the top of the gasometer. as the children went up nearer to it, they saw it was made of great plates of iron firmly riveted together, and that it did not rest on the ground, as they had supposed, but in the middle of a circular tank of water. "after the gas has been made and purified and measured," said mr. carter, "it is brought by underground pipes into this gasometer, and from here drawn off by other pipes into the houses. the weight of this iron shell bearing down upon the gas, gives pressure or force enough to drive the gas anywhere we wish." [illustration: the gasometre.] "but why do you put the--the iron thing in water, instead of on the ground?" asked kitty. "so as to make it air-tight, and give it a chance to move freely up and down. of course if the iron shell were empty its own weight would make it sink directly to the bottom of the water-tank and stay there. but gas, you know, is so much lighter than common air that it always makes a very strong effort to rise higher and higher, carrying along whatever encloses it. you saw that illustrated in the balloon that went up last fourth of july. now, as the gas from the works pours into the reservoir from beneath, it is strong enough to lift the iron box up a little in the water. of course that gives a little more room. then as more gas comes in to take up this room, the gasometer keeps on rising slowly. we make sure of its not rising above the water and letting the gas leak out, by means of the beams you see stretched across above it. they are all ready to hold it down in a safe position if the need should come. "on the other hand, as the people in town draw off the gas to burn, the gasometer would, of course, tend to sink down gradually. so we have the water-tanks made deep enough to allow for every possible necessity in that direction. in very cold weather we keep the water from freezing by passing a current of hot steam into it. if it should ever freeze, the gasometer might as well be on the ground, for it could not move up and down, or be trusted to keep the gas from leaking out around the edges. with these precautions, however, we know it is perfectly trustworthy." "i saw it one morning early, when i was out coasting on the hill," said philip, "and it wasn't more than half as high as it is now." "a great deal had been drawn off during the night and we had not been making any more during the time to take its place." "does it ever get burned out too much?" "no, there's no danger of it. we make enough to allow a good large margin above what we expect will be used." the children looked about a little longer, and then, with good-byes and many thanks to mr. carter, walked home again with papa, over the crisp, hard snow. next week philip had a composition to write at school. he took "gas" for his subject, and wrote: "gas that you burn is made out of soft coal. they put it in ovens and cook it until it is not coal any longer. the ovens are so hot you cant go anywhare near them but the men do with poles and big lether aprons. i would not like to shovle in the coal. i would rather have a balloon. they use two or three tons every day. it makes coke and tar and the gas that goes up the pipes. they make the gas clean and mesure it in a big box of water, and tell how much there is by looking at the clock faces in front. then it goes into a big round box made of iron and then we burn it. but i do not like to smell of it. you must not blow it out for if you do you will get choked. this is all i remember about gas. "philip raymond lawrence." racing a thunder-storm. if it had been a yacht in which we were speeding along at the rate of a trifle over a mile per minute, we should have "taken our reckoning," "hove the log," or done something nautical, and the captain would doubtless have reported in regular sea-faring terms that we were off oil city with lake chautauqua so and so many knots on our port quarter. but it wasn't a yacht, nor a schooner, nor a conestoga wagon, lightning express or catamaran, in which we were travelling neck and neck with one of the wildest looking storm clouds of hot mid-summer. no. it was--can you guess it? yes, a _balloon_. and this is how it all came about: fourth of july came upon the _fifth_ that year, (because of some strange oversight on the part of the folks who first hit upon the plan of dividing time into weeks, somehow the fourth will, every once in a while, strike sunday.) [illustration: inflating the "buffalo."] at least it did in cleveland; and although they were a day late, the clevelanders determined to have a big time. so they had sent for prof. samuel a. king, an aeronaut of distinction. balloonists, you know, are nearly always called "professors"--why this is so i don't _profess_ to know. and prof. king had arrived in cleveland a few days before, bringing his great balloon, the "buffalo." early upon the morning of the th he was on hand with the helpless monster all in a heap tied about with ropes, mixed up with netting and sand-bags, and supplemented with a big basket which looked a good deal like an inverted straw hat made for some huge giant. the netting was carefully spread out on the nicholson pavement in the centre of the pretty square that you will remember if you have ever been in cleveland. the bags were filled from a wagon-load of sand and hitched with snap-catches about the edges. so they stood about in a circle. then the aerostat, as the great bag is called, was unrolled and spread evenly over this. an oiled-muslin tube was tied to the neck, and its other extreme to a gas main in a hole which some of the workmen had dug for the purpose. next the gas was turned on. the bag began to rise, looking at first like ever so many young whales all huddled together. the men now began, under the professor's direction, to pull the netting over to hold the bag down. the sand-bags were brought closer and set along on either side of the tube. the bag now began to grow round and plump. groups of lookers-on kept growing, too, until all the square was alive with them. the helpers kept walking around the swelling globe, changing the bags to lower strands of the netting; and so it continued until by two o'clock the balloon was full--that is, allowance was made only for expansion when the balloon should have reached the clouds. every few moments the breeze would sway the monster to and fro, and it seemed chafing to break away. soon after, the basket was tied upon the ring, and into this a great heap of sand-bags was piled, and a lot of ropes, an anchor, an aneroid, thermometer, compass and other accessories tied into the rigging or outside of the basket. how grandly she stood there, the vast dome towering above the trees, her amber sides bright with decorations and her shapely globe held in leash by the white network--but bless me! here's more than four pages used up, and we haven't started yet. at precisely four o'clock the professor's cheery voice was heard all through the square as he sang out, "all aboard!" and his eight companions responded as soon as they could get through the dense crowd that surged on every side. now the sole remaining rope which held us to the earth was gripped by a score of eager men. the order came, "let go!" the basket was raised a few feet and then settled slowly back. this made the crowd laugh. "throw out two bags!" cried the professor. then--then how grandly we lifted! how the cannon roared and bands added their noise to the shouts of the hundred thousand people whose faces were all turned toward our little wicker car! the writer was sand-man, and following orders, he let out the contents of another bag which fell in a swift gray stream plump down into the midst of a little group of young ladies who were seated on a house-top. if it happens that _this book_ reaches that family, opportunity is now taken to apologize to those young ladies for thus pouring sand down the backs of their necks. well, we sailed along grandly, soon leaving the city far behind--i forgot to say that just as we were leaving, a darkey in a white apron came through the crowd bringing us a hamper of good things. what an appetite this keen upper air gave us, to be sure! we ate and drank and toasted everything and everybody. pretty soon one of the boys said, (we were all newspaper men, and spoke of each other as "boys"): "listen a moment!" and we all held our breaths. what supreme silence! the gentle sighing of the wind among the trees a mile below, the barking of dogs, or subdued shouts of excited villagers, was all we could hear--but hark! we were approaching a small town. in the square, through the gathering twilight, we could discern a crowd, and now there came to us, refined by distance, the familiar notes, played by the village band, of "up in a balloon, boys!" we passed over the village, and the professor pulled the valve cord gently, so we dropped towards the place and cheered in reply. "now let's give them a song," said the professor. [illustration: a plucky dog.] so he began, and we came in on the chorus: "oh! 'twas old sam simons, and young sam simons, old sam simons' son: now young sam simons is old sam simons, for old sam simons is gone." i wish the editor would only give me room to tell you about the scores of funny things that happened that afternoon; but after all, the real adventures happened the next day. so i can only speak briefly of the pretty carrier-pigeons we loosed, which flew swiftly back to cleveland, bearing our messages to the newspapers--short notes only, to be sure, wrapped about their slender legs, and which appeared in the papers the following morning. one of these i find in the scrap-book before me, for it was returned to me some weeks afterwards. it reads: "_we've just eaten supper out of our hamper, unhampered by any fears as to breakfast. supper above the clouds is what i call high living. we can see you yet, but you are only a smoky stain upon the shore of lake erie. the professor says we are to go into camp and then continue trip to-morrow. good-night._" it would never do, either, to forget the plucky dog which ran after our drag-rope as it trailed along the ground when we were quite near the earth, and held on with his teeth though we pulled him along over the stubble on his back, and never let go until we had jerked him plumb over a fence. i've been in all sorts of camps--military camps, hunting camps and camp meetings, but never dreamed of such a thing as a _balloon camp_ before! by the help of some farmers we filled the great basket with stones and then pitched a tent and made a fire at a safe distance. lines were run to trees in three directions, loosely to give the balloon "play" in case of much wind, and then we all lay down in our blankets and tried to sleep. at the very first signs of dawn we were up, and there she stood in the still air just like a vision. at sunrise a hospitable farmer invited us to breakfast, and wasn't it good? i'll never forget that coffee. by eight o'clock quite a large number of country folks had reached the field. teams were hitched all along the fences. now the professor announced that as he wished to make a long trip that day, he should carry plenty of ballast and so could allow only two persons with him. it had been agreed that we should draw cuts, and this was done good-naturedly. the [illustration: our balloon camp.] choice fell upon a photographer, and the writer. we were sorry indeed to leave our companions behind us, but there was no help for it. so we took our seats in the basket, said good-by, and were off. now we went up! _up!_ up! passing through a thin cloud that made everything below look dim and distant. we were in the region where _november spends the summer_. whew! how chilly it was. we wrapped our overcoats and blankets close about us and our teeth chattered. then we rubbed our hands and faces. why! how queerly they looked and felt. "ha! ha! look at the professor's face. why! there _ain't a wrinkle left_!" said the photographer. and so it proved. the aneroid told us that we were over three miles from the ground, and the atmosphere was so diminished in pressure that the internal forces of the body pressed outward and made the skin full and smooth. one of yesterday's party had provided some large envelopes with long red tails of tissue paper to drop into towns, and we wrote messages and enclosed them in some of these, putting sand in one end, and launched them. we watched them as they shot hither and yon in their swift flight toward the earth. the chance finder was requested to send the contents to the nearest telegraph office, but we never heard from any of them, save one. about noon we found by comparing our maps with the streams below that we had passed into pennsylvania; and not long afterwards we descried oil city set upon the creek, with all its hills covered with derricks and oil tanks. speaking of oil city, reminds me of a rather funny incident: for a couple of years i had been in correspondence with a young man who resided there, and who was also a journalist. his name and mine were just the same. i had promised faithfully to stop and see him at any time chance might bring me near his home. i took one of the envelopes and wrote a _regret_, dropping it over the city. it was picked up in the road and handed to him, but he always insisted that i had broken my promise unreasonably. at the rate in which oil city was left behind we knew our pace was very rapid, though to us it all seemed like a dead calm, for we kept just even with the wind. the professor said we could reach new england by midnight if the wind held and it didn't grow cloudy; but alas! for the past hour we had been watching a little fleecy nebulous bit of mist that seemed, like a spirit, to spring from the nothingness of the blue ether, growing constantly, and attracting other cloudlets which came toward it from all quarters of the heavens and were swallowed up. a growing, whirling wall of pearly gray mounted and spread its shadow over half the earth. we threw out sand and mounted above it. then it arose toward us again. it seemed as though we could reach our hands into its surging depths. over went seats, baskets, the tent--everything we could spare, and i'm not sure the professor didn't glare at one of his companions with malicious and deadly intent. the truth rushed upon us that we were racing with a storm. it was of vital importance to keep in the sun, for the moment the shadows below could place their chilly spell upon our steed, the gas would chill and condense, and we would drop! drop! swiftly to the earth. at last it came, and we knew it was inevitable. below us we could hear the crashing of thunder reverberating away into the depths of the black storm masses, and the lightnings every moment lit the weird scene with a grandeur but few mortals have ever witnessed. for a brief moment we hung suspended like mahomet's coffin in the centre of a great cave of pearl. shall i ever forget that glimpse of heavenly splendor? a single shaft of sunlight broke through its walls and then died like the last ray of hope. then downward we rushed! a mile nearer earth within the first minute! as the air grew denser we fell more gradually. our long drag-rope was out, weighing perhaps three hundred pounds. now we were closely enshrouded by leaden clouds. the rain ran down the bag in rivulets and trickled upon our heads. "look, oh look!" cried the professor. we were now below the storm, and along its dense ceiling could see its broad extent. we were above the mountains. no towns nor even houses could be discovered, only dense forests, through which the gale howled as among the rigging of a ship upon a winter sea. very quickly our drag-rope touched the tree-tops and began to glide among the swaying pines. "hold on at life-ropes!" shouted the professor, knife in hand. in another instant the basket gave a dreadful surge; a mass of pine boughs swept about our heads, followed by a strong jerk. the professor had cut the cord which bound the anchor coil. the anchor had dropped and caught among the limbs. we were safe! no! not yet. [illustration: the professor's dilemma.] the line must be shortened so we could clear the tree-tops. all three tugged at the rope. then other lashings were made while the great aerostat plunged about like a wounded leviathan. we were eighty feet from the ground. two of us found it convenient to go down the drag-rope, but the poor professor, tall and heavy, preferred to try the tree. this was wet and slippery, as well as full of projecting points of broken branches. about twenty feet from the ground the professor's clothes caught. he was in a great dilemma. amid a good deal of laughter we managed to liberate him, and as he reached the ground he exclaimed: "well, of all the scrapes i was ever in, this is about the meanest!" but help came even here. far down the slope we heard a shout, which you may be sure was quickly answered. then, after a while, the bushes parted and a half-score of woodsmen carrying gleaming axes ran to our aid. they were all thoroughly wet, like ourselves. "what can we do for you?" they asked. "cut down half a dozen of these pines. i want to save the balloon," answered the aeronaut. then you should have seen the chips fly! down came the trees, one after the other, and finally the one to which our steed was lashed. the gas soon escaped through great holes torn by the limbs, and our gallant craft was robbed of its power. standing upon one of the fallen trees i made the sketch you see before you. we found upon inquiring that we had landed in potter county, pennsylvania; and consulting our watches, found we had travelled one hundred and twenty-five miles in about two hours. we were made comfortable at a lumberman's cabin, [illustration: the wreck of the "buffalo."] and managed to get out of the woods in a couple of days where we could telegraph to our friends. it cannot be denied that after the excitement had passed we felt very much like an old farmer who listened to our adventures. he said: "mebbe some folks prefer to travel in a flying beelzebub, but i'm willin' to git along in a buck-board with a good road to put my feet agin when i git off." _you'll_ say, now, "i guess that race was enough for you!" but you're wrong; for i've had several trips since; and now you've a perfect right to retort, "well! you are a bigger _balloonatic_ than i took you for." perhaps you're right. august's "'speriment." august _was_ rather a troublesome boy. generous and jolly,--his playmates called him a firstrate good fellow, but older people complained that he was curious, meddlesome, and always "cluttering round." but here is mamma's opinion: "august was born to be busy. he is inventive too. he asks questions to gain information, and he handles things to see how they are made." "what is he tinkering at now, mamma?" asked tom. "he has got hold of an old, old book, full of _f ss_, and all yellow; he's rigged two pans in a barrel, and bought a naptha lamp, and locked us all out of the attic." "and he just came in with a covered basket, mamma," said katie, "carrying it ever so carefully. i was jumping rope in the hall, and he asked me not to joggle. what do you suppose he was doing, mamma?" "suppose we wait till he tells us," said mamma, smiling. "he's only trying some of his 'speriments," said wise little robbie, aged five. after the children went out, mamma took up her work and sat down by the window, watching the three outside, and waiting for her oldest boy, august, who presently came to take her into his confidence. "mamma, i am trying an experiment." "and is that something new, august?" with an encouraging smile. "but the _kind_ is new, mamma. did you ever hear of réaumur?" "who wrote that curious old book on the art of hatching fowls by artificial incubation? yes, august." "then will you come and see, mamma, what _i_ have begun to do?" he led the way, two steps at a time, to the attic. when they reached the door, august drew from his pocket a key, and unlocked it and led his mother in. a flour-barrel stood in the centre of the floor, closely covered. august removed the cover, and lifted up a piece of carpet. his mother looked in. within the barrel was suspended a large, deep pan, resting on three iron cleats. this pan was partly filled with hot water, and floating on the water was another pan--a shallow one--which contained a layer of sand an inch deep. over this was spread a piece of linen cloth, and in the cloth thirty-six large brahma eggs lay closely packed. in the center stood a neat thermometer. [illustration: the incubator.] "you have made your arrangements very neatly, august," said mamma. "of course i do not understand them exactly." "well, you see, mamma, this shallow pan gets its heat from the water beneath it. i put that in hot, and keep it just right with this lamp." saying which, he knelt in front of the barrel, and opened a neat little door, fitted with a brass knob and hinges. stooping down and looking in, his mother saw on a tall flower-pot, which stood upside down, a naptha safety-lamp sending forth a small, steady flame. "that keeps the temperature about equable;" said august, "but i have another lamp, larger than this, to use in case my incubator grows too cool." "when did you set them?" asked mamma. "this morning." "to-day is the first of march: then if no accident happens, and the eggs are good, you expect them to hatch on the twenty-first?" "yes, mamma, and the eggs are all right because i told grandma i wanted some _very_ fresh, and she saved them for me." "did grandma know of your experiment?" "oh! no, mamma. not a soul but you knows about it; and i want you to keep the secret until we know how it will turn out." "very well!" said mamma; "but if you lock the door you had better leave the key with me in case anything should happen. i will look at your incubator occasionally while you are at school." august gave his mother a grateful look--he felt so encouraged by her sympathy. "how warm do you keep the eggs?" she asked as he carefully replaced the carpet and cover. "réaumur says at °, that is about - fahrenheit.[a]" "must the eggs be kept at that temperature all the time?" "no, only through the first week. the second it is a little less and the third still less." "there is the luncheon-bell, dear; we must go down or the children will be trooping up here. i hope, my boy, that you will succeed." "if i don't i shall try again," said august. then, taking a final look to see that the thermometer and lamp were all right, he locked the room and they went down. he paid several visits to the attic during the day and evening, finding on each occasion that all worked well and steadily. before going to bed he refilled the lamp, so the supply of naptha shouldn't be exhausted; then he went to sleep and dreamed all night of eggs and chickens. in the morning he was up and at his incubator before any one else was stirring. the thermometer indicated that the eggs were a trifle cool, so he turned up the wick of the lamp. before going to church he turned the eggs. this he did twice daily, being careful not to jar them. the incubator worked well all day and all night. the next day was monday and he had his school duties to attend to. he left everything in good order, took the attic key to his mother, and went off to school full of confidence. alas! when mamma went up at ten o'clock, she could scarcely see across the room. everything was black with soot. the naptha lamp was smoking fiercely. the first thing was to get the window open, and put out the lamp. then mamma looked at the eggs. alas, again! there they lay covered with fine black soot. she took up one and tried to wipe it, but succeeded only in making a smirch which she could not wipe off. she knew then that the eggs were spoiled. in the midst of it all august came in from school having been dismissed early. poor august! he could scarcely keep the tears back. "well, august," said his mamma very practically, "i don't think a naptha lamp just the thing. they are very apt to smoke, and they are very inflammable." "yes," said august, trying to be cheerful. "failure the first! i shall try it again. grandma will give me some more eggs. i've only lost three days." "and _i_ will go to town this afternoon," said his mother, "and see if i cannot find a lamp which will be more reliable." there was no school that afternoon, so august cleaned the room, and supplied the incubator with fresh eggs, greatly encouraged by his mother's sympathy and interest. the other children were curious enough to know what was going on in the attic; but they could get no information. toward evening mrs. grant returned from town, bringing for her little boy a large tin lamp which would burn kerosene. he lighted it and adjusted the wick to just the right height. then it was placed within the barrel to warm the second setting of eggs. day after day august and his mother watched and tended them. everything progressed finely. on the next monday the eggs, having been in the incubator a week, were far enough advanced to be tested. at a south window there hung a heavy green holland curtain. in this mamma allowed august to cut a hole, a little smaller than an egg, and she herself staid to assist him. when all was ready, she handed august the eggs one by one. one by one he held them to the aperture. the first seemed quite transparent. in vain august turned and turned it--there was nothing to be seen but the yolk floating at the top. with a sigh he laid that aside and took up another. "o, mamma, look!" he cried excitedly. mrs. grant examined it with great interest. not only could she distinctly see the dark form of a little chick, particularly the head with its immense eye, but bright blood-veins were also plainly defined, branching out in all directions from the body. another and still another of the eggs looked like this one. august was greatly excited. "they are lively enough!" he said. "see, mamma, this one moves, and this!" then came one that was dark and shaky. "addled," pronounced august. after this a number more appeared as promising as the former ones. finally all were tested. they were pleased enough with the result. three were clear--that meant there were no chickens within the shells; one was addled; and thirty-two contained live chicks. august was so wild over this discovery that his hands grew unsteady, and he unfortunately dropped two of the eggs and broke them. this left him but thirty likely to hatch; but these were all very promising. "i am sure we will succeed now, mamma," cried august gaily. "it looks like it, certainly," said mamma. but alas for poor august's bright hopes! and alas for the expected chickens! whether august was too confident and grew careless, or whether it was one of those unforeseen accidents that _will_ happen, will never be known; but this is certain, that the next morning when august went, later than usual, to look at his incubator, he found the thermometer had gone up to and must have been at that temperature some time, for in egg after egg, which he opened in despair, was a poor little dead chick. even if a boy is fourteen years old, he cannot help crying sometimes over a great disappointment. poor august put out his lamp with sorrowful breath and some of his tears fell upon the hot chimney which hissed as if in mockery. then he locked himself in his own room, threw himself on the bed, refused his breakfast and gave way to his grief. tom, katie and robbie all tried to get at him, but without avail. katie coaxed with loving words. robbie murmured, "poor gussie!" tom said "never mind, old fellow, if your 'speriment has failed. come and play ball." august's reply was not very polite. "my experiment hasn't failed, and that is all you know about it, tom!" but the word "fail" seemed to rouse him, to restore his courage; for presently unlocking the door and coming out, he said quietly to himself, "i shall just go down to grandma's for some more eggs--that's what i shall do!" grandma was curious to know what he did with so many eggs; but she asked no questions. she had great respect for august and his 'speriments. she only said, "this makes one hundred and eight eggs, child. now, if i had set all these, and if they had all hatched, what a lot of little chickens i would have had!" "ah!" thought august. "if!--" and he drew a long sigh. mamma, meanwhile, had been up to the attic to look at the incubator, knowing nothing of what had happened. great was her amazement to find the lamp out, a basin full of broken eggs and little dead chicks, and the incubator itself deserted and empty. "why, august!" she cried, as she met him in the door with a basket of fresh eggs. "what has happened, dear child?" "only failure number two;" he answered, trying to speak cheerfully, though even yet the tears lay high. "they got too hot in the night, mamma." "yet you are not quite discouraged?" said mamma. august held out his basket with a smile. so once more the incubator was set. "we must take more pains this time," said mamma. "yes'm," answered august, "i'll try not to let any thing happen to these." things did work more smoothly this time. the temperature was kept about right, the eggs were tested successfully and without accident. one week, two weeks, two weeks and a half, and then things happened again, things which came near being serious enough. it was saturday afternoon. august was going with the other children to a circus. he had turned the eggs carefully and sprinkled them lightly with warm water. he had admitted the children into his secret, and they were all in the room waiting for him. "these eggs are a little cool," said august, putting one up to his cheek. "i must leave them just right, i think i will fill the lamp and turn it up a little. tommy, will you take the lamp out?" down on his knees tommy went, and drew out the lamp which he set on the floor. then, kneeling still above it, he blew hard, directly down the chimney. "puff! bang! _crack!_" went something, causing august, katie and robbie to start violently, while poor tommy, with his hands to his eyes, rolled over on the floor with a groan. "mamma, oh! mamma!" screamed katie, "the lamp is 'sploded!" "and tommy's killed!" shrieked robbie. mamma flew up the stairs and to tommy. "oh! his eyes!" she cried. "quick, august, water!" "oh! my poor tommy!" sobbed little robbie. "see him all b'eedin', b'eedin'!" august came running with the water, and knelt down and held the basin while katie flew for a sponge and soft linen. when the blood was washed off, and his smarting eyes had been bathed with fresh, cool water, tommy discovered that he had been more frightened than hurt; and mamma and the rest were greatly relieved to find his worst wound, a slight cut between the eyes, could be cured by court-plaster. it was a great wonder, however, that more harm had not been done; for when the child blew so forcibly down the chimney, the wick shot up out of the lamp and the chimney shivered in pieces; one of the pieces had struck his face, making the cut, while the hot air and smoke flashing into his eyes caused them to smart fiercely. august had neglected to fill the lamp at the proper time, and the oil had burned nearly out. it was the sudden forcing of air down the tube which caused the explosion. "i thought you said 'twas a safety lamp!" said katie indignantly. "'tisn't half so good as our un-safety ones;" declared robbie. "it's never safe to blow directly down upon a full flame in any lamp," said mamma. "the wick should always be turned down first and the flame gently blown." "accident the third;" said august ruefully. "mamma, do you feel like trusting me any farther?" his mother smiled. "the usual experience of inventors, my son." sunday passed quietly. monday with its school duties was well over. tuesday morning--"three weeks to-day!" said august, and half fearfully opened his incubator. "_peep! peep! peep!_" the lad trembled with excitement, and a flush of joy spread over his face. he could hardly believe his ears. "one, two, three," he hurriedly counted, "four, five, six." on he counted, up to twenty eggs chipped or cracked. one chicken was half out of its shell, and one, quite independent, was scrambling over the rest of the eggs. august held his breath and looked at them as long as he dared to keep the incubator open. then softly closing the lid, he rushed down stairs. "hurrah! hurrah!" he shouted at the door of his mother's room. "they're hatching, mamma! they're hatching!" "are they, really?" asked mamma, pleased enough, and she hurried up the stairs, closely followed by the children, whom august's joyful cry had aroused from their sleep. in great excitement they clustered around the barrel. "oh! what a cunning, fluffy one!" cried little katie, as she spied the oldest chick. "but what is the matter with that other one?" asked tommy. "he has just left the shell and is not dry yet," august explained. "as soon as he is dry he will be downy like the other." "hear em say '_peep! peep!_'" cried little robbie, grasping the edge of the barrel with both hands, and stretching his short legs to their utmost extent in order to get his eyes high enough to look over the edge. "what lots are cracked!" said tommy. "oh! august, here is one cracked all round." "yes," said august, "that chick will soon be out." even as he spoke the shell parted, and a third little bright-eyed chicken struggled out and looked about in amazement. the children could have watched them much longer with great interest, but mamma was afraid the incubator would get too cool, and she advised august to cover it. "how _do_ they do it, mamma?" asked katie. [illustration: how the chicken is packed.] "the little chick is packed very wonderfully in his shell," said mamma. "his head under his wing, legs folded up with the feet toward the head, his bill coming out from under one wing. this bill is furnished with a little hard point on the top. when he is ready to crack the shell and come out, he begins to move. he turns his whole body slowly round, cracking the shell as he goes, by pressing with his whole force against it, the hard, sharp point on the top of his bill coming next the shell. when he is a few days old this hard point drops off. just before he hatches, after the egg is cracked all around, he frees his head from his wing and struggles to stretch himself. then the shell parts and he gets his head out, and presently his legs, one after the other. i forgot to say that just before hatching he gradually absorbs the yolk of the egg into his body, and that nourishes him for twenty-four hours after hatching." [illustration: how the shell is cracked.] "it's very curious, isn't it?" said tommy. "i didn't know anything but hens or ducks could hatch eggs," said katie. "why, katie!" exclaimed august, "there is a place at canton, in china, where _thousands_ of ducks' eggs are hatched artificially every day. there are twenty-eight rooms to the establishment, and all along the sides of these rooms are rows of sliding trays filled with eggs. these eggs are put in the first room the first day; on the second day they are moved to the second room; and so on, until they hatch in the last room. the heat is graduated, the last rooms being cooler than the first. all these eggs are hatched by the heat of the rooms." "if they hatch thousands every day," asked tommy, "what do they do with the little ducks?" "they hatch them for the people in the neighboring towns," replied august. "the chinese are very fond of ducks and ducks' eggs. a gentleman who has been to canton, and seen the hatching-rooms, told me he had seen people take eggs there to be hatched. they would pay for the hatching and then one of the men in charge of the rooms would count their eggs, and give them just as many little ducklings." "i guess they don't have accidents there, then," said katie. "_i_ won't have accidents _always_," august replied. "but what _do_ they do with so many ducks?" asked tommy. "why, half the poor chinese people near the coast live on the water all the time in boats that are half houses. of course they could not keep hens, but they can keep ducks and they do." "oh, yes!" cried tommy. "i 'member how papa told about seeing them fed and called into the boats. he said every flock knew its own call, and would go scuttling through the water to the right boat. he thought they were in this d'edful hurry, cause the last one got whipped." "what shall i do about school, mamma?" august asked. "oh! go, and recite your most important lessons," she answered wisely. "i will take care of the eggs and chickens till you return." it was just as well for august to be occupied, since the hatching, although it went on surely, was slow work. with great faith in his incubator, august had previously built a little yard for the expected chickens. it was in box form, about eight feet long and two feet wide. in the center was a feeding-tray and water tank, and at one end a hover. this hover (h) was [illustration: the artificial mother.] lined with soft fur loosely tacked to the top and sides and hanging down the front in narrow strips to form a curtain. it sloped from the front to the back. the water tank was a stout earthen bottle in a saucer; a small hole near the bottom of the bottle let the water, drop by drop, into the saucer, so that as the chickens drank, the supply in the saucer was continually freshening. the bottom of the yard was covered with gravel three inches deep. this neat yard was now waiting down stairs in a sunny shed room to receive the chickens. august went to school, and on his way home called for his grandmother to go up to the house to dinner. grandma knew that it was just three weeks since august had taken the last eggs, and that twenty-one days was the time allotted by nature for the bringing forth of chickens, so she shrewdly suspected what she would find; but it had not occurred to her that she would find chickens alive without the aid of a hen. "grandma," asked august, as they walked along "when you set a hen on thirteen eggs, how many do you expect will hatch?" "i hope for all," she replied, "but i seldom get all. i think ten out of thirteen is a very good proportion." "my incubator beats your hens!" thought august. when they reached the house he took her straight to the attic. "well, i never!" she exclaimed. "so that is your secret, august! well, i declare! and it really hatches the eggs, doesn't it? i always knew, child, that you would invent something wonderful." "i didn't _invent_ much," he said modestly. "in , réaumur, the french naturalist, gave an account of his experiments in hatching eggs in barrels set in hot-beds of horse-manure; and the chinese and the egyptians have hatched them for ages in ovens." "but this is by hot water and lamps," said grandma. "yes," said august, "i never saw an incubator before i made this; but, grandma, i had read of them made on the same principle." "at any rate," said grandma, "i think that you deserve great credit for patience and ingenuity." by evening thirty chickens were hatched from the thirty-six eggs. the other six gave no signs of life. by grandma's advice they were left in the incubator "to give them a chance," but they never hatched. the next morning all the members of the family took the chickens down-stairs, even robbie, who took two in a basket, and deposited them in their new home. then their food was prepared, the yolks of hard-boiled eggs crumbled up fine, bread crumbs, milk, and a little fine cracked corn. after a few days they could be fed almost entirely upon the cracked corn. the whole family then stood around the yard admiring the brood, thirty little, bright-eyed, yellow, fluffy balls. they soon learned to eat and to drink, and were busy, happy little creatures. they would run under the hover when they wanted warmth or quiet, just as naturally as they would have run under a mother hen. the box was built on castors, and could be rolled from window to window, and thus kept in the sunlight, in which the little creatures reveled; and at night it could be pushed near the stove. of course august had to renew the gravel very often, and he was very particular to keep the food dishes sweet and clean. when the weather grew warm enough the yard was rolled into an open shed, and they could run out of doors. these chickens were considered very wonderful, and many visitors came to see them. they grew fast and were as tame as kittens. day after day the children came to feed the pretty pets, bringing them young clover tops and tender grass. katie treated them with her birds' canary and hemp seed. robbie gave them bits of his cookies and cakes. anything that the children liked to eat, these little chickens liked also; and when they heard the little boots coming towards them they would perch on the edge of their yard and chirp and peep and coax for their dainties. by and by their wings began to grow and the fluffy down was changed to feathers. grandma said that now they must have meat occasionally, chopped up fine, and they had it wednesdays and saturdays. the little creatures were frantic for the meat. they would fly upon august, and, if they could get there, into the dish, which they more than once overturned. when their plumage was well out they were handsome fowls. august built a large coop and out-door yard for them, but they were not often confined in it, for the children loved to have them about with them, and watched them as carefully as a hen mother could have done; and great was the joy of katie and robbie as they ran to their mother to report the first crowing of the little cockerels. when last i saw them they were well grown. the pullets, august proudly informed me, were laying. it was the glorious fourth. torpedoes were the order of the day, and katie and robbie were amusing themselves by throwing the snappers in all directions, and seeing their feathered pets run to eat what they could never find. the other fowls, disturbed by the noise of the day, preferred to keep hidden away in their houses, but these liked to keep about with the children and see the fun. august began his experiments when some of my young readers were quite little children. he has continued them through several seasons, until now, after much study and patient industry, he has enlarged and greatly improved his incubator. he has changed its form entirely, and has attached an electric apparatus which regulates the heat, and avoids all danger from smoke. he has applied for a patent, and has made arrangements for taking care of a large number of chickens as early as february, being still greatly interested in this successful "'speriment." ----- [a] fahrenheit and réaumur were both inventors of thermometers. those commonly in use are fahrenheit's. the birds of winter. it seems strange that any birds should stay with us during the cold and frost when there is so much food which they like in the southern part of our country. men of science wonder why they do remain here, and are unable to account for it. perhaps it is because it is the true home of these birds which remain, and they prefer to search long and diligently for their scanty food, and bear the cold and the winds and the frost, rather than leave it. this is as _we_ should do, and doubtless the birds that stay through the winter love _their_ homes just as much--as a bird possibly can. of course everybody,--that is, everybody except the tiniest, wee baby, has seen the winter birds, some of them; at least the chickadees, the snow-birds, and downy woodpeckers, and bluejays and shore larks. _but are you acquainted with the little fellows?_ do you know where and how they live, and what they eat, and of their habits and songs? [illustration: the chickadee.] a great favorite of mine is the chickadee, with his black cap and white shirt bosom. this active little gentleman is the most social and friendly of them all. if out in the country, this little fellow in company with his mates will twitter gaily at sight of you, every now and then looking curiously at you as if asking, "and who are _you_, sir?" or "who are _you_, ma'am?" and pecking his way gradually nearer and nearer will inspect you in the quaintest and merriest way. afraid! o no, not they. mr. samuels, a writer about birds, says that he once had an inquisitive little chickadee perch on the end of his boot and sit there watching him inquiringly. they have even been known to feed from the open hand. if you will daily scatter some crumbs for them before the door, or upon the window-sill, you will learn for yourselves how neighborly they are. still the chickadees are strangely tender, needing a warm, cosy nest to shield their little bodies. they cannot make their nests on the limbs of trees. oh, no, that wouldn't do, for the first thing they knew the wind would blow, blow, and down would come their home. so they hunt around in the woods or along the rails and posts, for the nests in the wood that have been deserted by the woodpecker, who has flown away to a milder clime. if the chickadees can not find these, they set to work themselves and with great labor dig a hole in a tree, or post, for their winter quarters. they prefer decayed trunks or posts so they can work more easily. to the bottom of their holes they bring pieces of wool, moss, and feathers or hair, and weave warm carpets and curtains to make cosy their little homes. the chickadees are very active, lively little things. they are always in motion; now hopping along in search of food, sending forth the peculiar cry that gives them their name, and then alighting on the tree limbs and moving from one tree to another "traversing," as wilson, a great authority on birds, says, "the woods in regular procession from tree to tree, and in this manner traveling several miles a day." they are very strong for their size, and will hang below a limb supported by their claws, with their head downwards, which we should think would make them dizzy, but it does not seem to. these little roamers of our roads and woods are so genial, companionable and social, that not only do _we_ enjoy their society, but other birds are enchanted with them and seek their company. the chickadees do not object. and so brown creepers, nuthatches, downy woodpeckers, and other birds, often join them in their merry rambles and scrambles. they feed mostly on very small insects and eggs, such as infest the bark of trees, but will eat almost anything offered them; even meat they will peck from a bone. pleasant, indeed, in the midst of winter is this little bird's cry: "_chick-a-dee-dee-dee! chick-a-dee-dee-dee!_" pleasant his sharp whistle: "_pe-wee! pe-wee! pe-wee!_" how much we should miss these amiable favorites should they ever take a notion to desert us! they stay with us throughout the year, but in summer they are shyer than in winter for they rear their young then. it is not until their family cares are over in the autumn, that they gather in small flocks and resume their merry life and social ways. [illustration: the black snow-bird.] another very interesting and neighborly winter bird is our familiar snow-bird, often called the "black snow-bird" to distinguish it from the snow bunting or "white snow-bird." these tiny birds visit us from the north. their journeys extend over the whole breadth of the united states. they appear here in the latter part of october, and are first seen among the decaying leaves near the borders of the woods, in flocks of about thirty. if molested, they at once fly to the trees. as the weather becomes colder they approach nearer the farm-houses and towns. they are real weather prophets. when a storm is near at hand they gather together in large flocks, and work very, very diligently in search of food,--doubtless making provision for the time of wind and storm when they can get none. but it is after the snow-storms, when the ground is white with the downy flakes, that the snow-birds become the most friendly. how pleasant it is then to see them gather about the house, and around the barn and out-houses, to search for edibles. not only then do they appear in the country-places, but even in the crowded city their little forms may be seen in multitudes, on the snowy streets and in the windows. they build their nests near the ground, often on a stump or log, or in a deep thicket, in such a manner as to be shielded from the wind and storms. they construct their homes from bits of fine grasses and leaves, and it is interesting to observe what wonderful architects they are. the snow-birds, i am sorry to say, though friendly with us are not, like the little chickadees, peaceful among themselves. they are often very quarrelsome, and will peck at each other in a way that little birds should not. perhaps they "make up" with one another and are good friends again. i hope so. the snow-birds are very nimble on the ground, and, i guess, can eat faster and more for their size than any other winter bird. it is a very funny sight to see them scratch away the snow with their tiny feet to get their food, which, when insects and eggs are not to be had, is the seeds of many kinds of weeds that still rise above the snow, and along the border of the roads. sometimes, perhaps, you have come upon a dead snow-bird in the morning following a cold night, and perhaps have wondered if the poor little creature froze to death, and why he did not die at home. but the snow-birds are sometimes affected with a dizziness or faintness which makes them fall from the limbs, or during their flight. _what_ makes them dizzy or faint, we do not know; not from hanging head downwards like the little chickadees, surely. but they often, alas! come to their death through this affection. the snow-birds have a peculiar cry of "_chuck! chuck!_"--and another of "_chit, chit-a-sit!_" which however, they seldom utter except when taking flight. they stay with us until about the th of april, when they wing away to the north or to the higher ranges of our mountains. somewhat similar to the snow-birds are the snow buntings or "white snow-birds." they appear every winter in large flocks, often of many thousands. they are sometimes called "bad weather birds," from the fact of their moving to the northward during fine weather and to the southward on the advent of deep snow-storms. they are much shyer than either the chickadees or snow-birds; but they are often seen on the roadsides and in the lanes searching for the seeds of weeds that grow there. on the sea-shore, which they greatly frequent, they live on small shellfish. it is curious that the greater the snow and the colder the weather of winter, the whiter do the snow-buntings appear. they are very swift flyers, and often in flocks of great numbers seem to be a cloud of snow-flakes driven before a storm. they make their nests in the fissures of the rocks, forming from grass, and feathers, and the down of the arctic fox, a very cosey home. they frequent the roads and lanes in the vicinity of boston, and their white forms and busy beaks can be seen throughout the winter season. [illustration: the snow bunting.] they have peculiar notes like a clear whistle, and a "_chirr, chirr!_" which they utter when flying. a very fine little bird quite common in this state in the winter season, is the brown creeper, with its showy brown and white coat. these active little creatures are great lovers of the woods and pass their lives among the trees. unlike the chickadees and nuthatches, who also are partial to the woods, they very rarely descend to the ground to either hop about or hunt for food. nor do they, like the two former birds, ever hang to a limb with their heads downward. still the brown creeper seems to be constantly in activity, and hunts most diligently for the insects it feeds upon. this it does somewhat in the manner of the woodpecker, by clinging to the trunks or branches of trees, supporting itself by its stiff tail-feathers and thus moving about quite securely. [illustration: the brown creeper.] they are very methodical. they strive to get every insect from a tree that there is on it, before leaving for another. so they generally alight near the foot of a tree and gradually climb to the top; an insect must be very, very small to escape their piercing gaze. they often work around a tree in spirals, and so are at times lost to the sight of an observer of their ways; and if the watcher runs around to the other side of the tree, very likely by the time he gets there, lo! they are back to the former side. but they are not at all shy, and though not as neighborly and social as the chickadee, or snow-bird, still they will not fly away from the presence of unmolesting persons. the brown creeper has not the bill suitable to excavate a hole for himself, so he is obliged to find a hollow trunk, a squirrel's nest, or a deserted woodpecker's home. here the little bird builds a nest of dry twigs and lays its pretty eggs. as the mid-winter cold deepens they retire to the depths of the woods, or into the brown and sheltered thickets, where their little cry of "_chip, chip_," and "_cree, cree, cree_," may be frequently heard; and very pleasant it is, too. very useful they are, these little brown creepers, as well as the chickadees and nuthatches, for they help preserve our beautiful trees and shrubbery from the destroying worms and insects. i have mentioned the nuthatches. these birds, a little larger than the others before noticed, are not so numerous as the chickadees and snow-birds, but they are very interesting. the name of nuthatches was given to them long ago, because it was supposed they broke the wood nuts by repeated _hatchings_ or hammerings with their bills. but now men of science, who study birds, do not think that is true, and believe the nuthatches to be wrongly named. [illustration: nuthatches.] it was also thought that the nuthatches, like the squirrels, lay up in the summer a store of nuts for their winter use. but this also is doubted, since the nuthatch will climb along the trees and limbs in search of insects and larvæ when the tree hangs full of nuts. so it is thought their principal food is composed of ants, seeds of various shrubbery, bugs and insects. while the female bird is sitting on her eggs, the male nuthatch displays a great deal of care and affection, supplying her regularly with the choicest food he can collect. with this he flies away to the mouth of the hole where they have established their home, and calls to her so tenderly, offering her the delicacy he has brought. he seems to call to her sometimes, simply to inquire how she is, and to soothe her labors with his incessant chatter. seldom does he venture far from the nest, and if any danger threatens he instantly flies back to alarm her. the white-breasted nuthatch is known by his cry of "_quank, quank_," repeated frequently as he keeps moving along the branches of a tree, piercing the bark with his bill and breaking off pieces in search of insects and their larvæ. this affectionate bird, like the little chickadees, rests and roosts with his head downwards; and also like them, is very curious and inquiring. if you are in sight, he will gradually make his way to you and reconnoitre your appearance, as if he would learn who you are. there is also another bird of this species called the red-breasted nuthatch, who is seen in new england, in winter, and who leads a similar life to his white-breasted relative. [illustration: the downy woodpecker.] though most of the many species of woodpeckers leave us on the advent of cold weather, still there are some that remain. my little readers, i am certain, have nearly all seen the round homes of the woodpecker. you may observe them in almost any wood. they are about alike except in size and situation. a round hole in a tree or post is all you will see from a distance; but if you can climb,--for their holes are usually more than six feet from the ground,--you may look down into the deep home itself. how much patience and perseverance they must have to dig, bit by bit, such straight deep nests. these holes are seldom lined with any thing, but are generally enlarged at the bottom so as to give the family more "elbow room." the one we know best in winter is the downy woodpecker, the prettiest and smallest of the tribe. it builds its nest in various trees, preferring the apple-tree, poplar and birches. its hole is smaller than those of other woodpeckers because, i suppose, the bird itself is so much smaller that he can do with less room. the downy woodpeckers are very sociable; and although they themselves are not gregarious, you may often see them followed by chickadees, creepers, nuthatches and wrens, whose company they appear to be pleased with. they are not shy of man, but, unlike most of their tribe, haunt roadsides, orchards, and grounds about houses and out-buildings, which they prefer to the deep forests. they are generally seen in pairs, and are very active little birdies. in searching for food, insects and eggs, they move from tree to tree and thus pass the day. they rarely alight on the ground. their ordinary cry is a "_chick_, _chick_," repeated rapidly. a somewhat larger woodpecker, called the hairy woodpecker, is also an inhabitant of our woods in winter and much like the downy woodpecker in habits. these are the principal and most common of our winter birds. there are some others sometimes seen, such as the tree-sparrow, blue-jay and golden crowned wren, but space forbids an account of their ways and songs. i hope what i have told you of the winter birds will induce you to study and observe more closely their almost human ways. something about light-houses. you have all heard of the seven wonders of the world; did you know that two of these wonders were veritable light-houses? about b. c., cheres, the disciple of lysippus, cast the famous brazen colossus of rhodes, a statue of the sun god apollo, and erected it at the entrance of the harbor where it was used as a light-house, the flames which crowned the head of the sun god by night serving to guide wandering barks into his rhodian waters. [illustration: fourth order light-house, at penfield reef, l. i. sound.] for eighty years its hundred brazen feet towered superbly above port and town, and then it was partly destroyed by an earthquake. for nearly a thousand years the sacred image remained unmolested where it had fallen, by greek and roman, pagan and christian; but at last the saracen owners of rhodes, caring as little for its religious association as for its classic antiquity, sold the brass of it for the great sum of £ . , to the jewish merchants of edessa. just about the time that the colossus was set astride the rhodian harbor, king ptolemy philadelphus caused a noble tower of superb white stone, four hundred feet high, to be erected by an architect named sostrasius, son of dixiphanes, at the entrance to the port of alexandria, which was a bran-new busy city in those days, a mere mushroom growth in that old, old egypt, where the upstart ptolomies were reigning on the throne of the pharaohs. it is said that this sostrasius didn't want his own name to be forgotten, so he carved it deep in the stone of the tower and covered it over with plaster whereon he inscribed by royal command: "king ptolemy to the gods, the saviours, for the benefit of sailors." josephus tells us that the light, kept burning on the top of this pharos, as it was called, probably from a word that signifies _fire_, was visible for forty miles at sea. for a thousand years it shone constantly until the alexandrian wonder likewise fell a prey to time and the saracens. the words pharos-phâre, faro, etc., have been adopted into more than one european language to express light-house or sea-light. some persons suppose that great mirrors must have been used to direct the light on the pharos and keep it from being lost, but it is most probable that no more effective means of illumination than a common fire was employed. the only other light-houses of antiquity of which any record has been preserved are the tower of conira in spain, which humboldt mentions as the _iron tower_, and a magnificent stone light-house at capio, near the mouth of the guadalquiver, that strabo tells us about, on a rock nearly surrounded by sea. then tradition points out cesar's altar at dover, the _tour d' ordre_ at boulogne, a roman pharos at norfolk, and, in early british history, st. edmund's chapel at the same place, as having been originally intended for sea-lights. though we are far ahead of our forefathers in our scientific apparatus for illuminating light-houses, we have never equalled them in magnificence of architecture; for, in point of grandeur, the _tour de corduan_ at the mouth of the river garonne, in france, is probably the noblest edifice of the kind in the world, and it is nearly three hundred years since it was completed under henry iv., having been twenty-six years in building. [illustration: a modern light-house] all these centuries it has stood strong on its great reef, and has served to guide the shipping of bordeau and the languedoc canal, and all that part of the bay of biscay; and it promises, in all human probability, to show its steadfast light for centuries to come. corduan is stoutly built in four stories, each of a different order of architecture, highly ornamented and adorned with the busts of the kings of france, and of the heathen divinities. the first story contains the store-rooms, the second, the so-called king's apartments, the third a chapel, and the fourth the dome or lower lantern. the tower completed is feet high. when this splendid structure was completed no better method for illuminating was known than by burning billets of oak wood in a chauffer in the upper lantern; and it was considered a great matter when a rude reflector in the form of an inverted cone was suspended above the flame to prevent the light from escaping upward. it is not known, in fact, that any more effective mode of lighting was employed until , not much more than one hundred years ago; and then the radiance was not especially brilliant as it would seem to us. at that time smeaton the engineer began to use wax candles at the eddystone light-house, which soon degenerated to tallow dips, probably on account of the expense, and they must have given the keeper abundance of occupation in the way of snuffing and replenishing. in a french scientist, m. lenoir, made an epoch in the history of light-houses, and in the progress of civilization as well, when he introduced an improvement in the way of lighting up the _tour de corduan_; for, of course, the comparative safety in coast navigation attained to by means of our modern light-house system is of the first consequence in commerce and international communication, which means the spread of science, enlightenment and religion throughout the world. m. lenoir placed argand lamps with parabolic mirrors or reflectors in the lantern, which is, as it appears, a glass room on the summit of the tower entered by a trap-door at the head of a spiral staircase. such a great change having been brought about, men of science have not rested content, but have gone on making one advance after another. in the famous diaptric instruments of mr. fresnel were placed in corduan on trial, and proved such a grand success that, gradually, they have been universally adopted. the wonderful lens which you saw at the centennial belongs to a diaptric refracting light of the first order, and oil lamps constructed on the fresnel principle, and, placed with lenses of different orders, according to the light-house they are used for, serve an admirable purpose. lard is found to be the best illuminator, as a general thing, for the light it casts through lenses of the first order reaches as far out to sea as it is possible for any light to be seen on account of the convexity of the earth. experiment has proved it safer than mineral oil, and it is cheaper than gas, which however is occasionally used near a city whence it can easily be obtained. only in some few special instances electric light, the most intense procurable, is employed. [illustration: light-house on mt. desert, coast of maine.] the centennial birth-day gift of the citizens of france to the american republic is a colossal brazen statue of liberty, which is to be a pharos to light the shipping of the world into new york harbor. it will stand on bedloe's island, and from the torch in its uplifted hand will flash a calcium light. only the hand and arm were finished in time to be sent to the exposition; but these were on so gigantic a scale that a man standing in the little gallery which ringed the thumb holding the torch seemed like an ant or a fly creeping along at that height. sir walter scott--dear sir walter, whose "tales of a grandfather" and scottish stories and poems were so delightfully familiar to the boys and girls of the last generation, left a charming little diary of a voyage he made in the summer of , on board a light-house yacht, in company with the commissioners of northern lights,--who have charge of the light-houses in scotland, as the elder brethren of trinity house have of those in england,--their surveyor-viceroy, the engineer stevenson, and a few other gentlemen. the first light-house they visited was an old tower, like a "border keep," still illuminated by a grate fire on top. the commissioners think of substituting an oil revolving-light; but sir walter wonders if the _grate_ couldn't be made to revolve! next they came to bell rock, which, in olden times, was the terror of sailors feeling their way in and out of the islands and rocks and shoals of the beautiful, perilous coast of scotland. inch-cape rock, as it was then called, had shipwrecked many a helpless crew before the abbot of aberbrathock, fifteen miles off, out of pity caused a float to be fixed on the rock, with a bell attached which, swinging by the motion of the waves, warned seamen of the danger. many years later, when abbot and monastery bells had all become things of the past, a humane naval officer set up two beacons on bell rock by subscription; but they were soon destroyed by the fury of the elements. at last in , people began to realize the danger of this terrible reef in the highway of navigation, and the commissioners appointed mr. robert stevenson to erect a light-house on this point. it was a perilous undertaking, and once the engineer and his workmen made a very narrow escape from drowning; but it was successfully accomplished by the brave and skilful stevenson. sir walter thus describes this famous beacon. "its dimensions are well known; but no description can give the idea of this slight, solitary, round tower, trembling amid the billows, and fifteen miles from arbraeth (aberbrathock), the nearest shore. the fitting up within is not only handsome, but elegant. all work of wood (almost) is wainscot; all hammer-work brass; in short, exquisitely fitted up. you enter by a ladder of rope, with wooden steps, about thirty feet from the bottom where the mason-work ceases to be solid, and admits of round apartments. the lowest is a storehouse for the people's provisions, water, etc.; above that, a storehouse for the lights, oil, etc.; then the kitchen of the people, three in number; then their sleeping chamber; then the saloon or parlor, a neat little room; above all the light-house; all communicating by oaken ladders with brass rails, most handsomely and conveniently executed." in the course of the voyage mr. stevenson determined that his "constituents" should visit a reef of rocks called _skerry vhor_ (skerrymore), where he thought it would be essential to have a light-house. sir walter's description of this visit is quite amusing and perhaps you would like to read it. the wind had blown squally all night, and in consequence everything and everybody were pitched and tossed about at a great rate, on board the little vessel. nobody relished the attempt to land under these circumstances on this wild ridge. "quiet perseverance on the part of mr. stevenson, and great kicking, bouncing, and squabbling upon that of the yacht, which seems to like the idea of skerry vhor as little as the commissioners. at length, by dint of exertion, comes in sight this long ridge of rocks (chiefly under water) on which the tide breaks in a most tremendous style. there appear a few low, broad rocks at one end of the reef, which is about a mile in length. these are never entirely under water though the surf dashes over them. pull through a very heavy swell with great difficulty, and approach a tremendous surf dashing over black pointed rocks--contrive to land well wetted. we took possession of the rock in the name of the commissioners, and generously bestowed our own great names on its crags and creeks. the rock was carefully measured by mr. s. it will be a most desolate position for a light-house--the bell rock and eddystone a joke to it, for the nearest land is the wild island of tyree, at fourteen miles distance. so much for the skerry vhor." [illustration: light-house at "the thimble shoal," hampton roads, va.] as might have been expected, the commissioners were discouraged at the aspect of affairs and delayed the work from year to year, but at last, in , the board placed this serious undertaking in the hands of mr. alan stevenson. mr. stevenson has left us a thrilling account of his noble work on skerrymore rocks, than which no worthier monument was ever left behind to the memory of a gifted and conscientious man. in the first place he had to build barracks for his workmen on the isles of tyree and mull, and then to begin the foundation of the tower on the only one of the gneiss rocks of the reef which was broad enough for the purpose, and this is but barely so, for at high water little remains around the tower's base but a narrow band of a few feet of rugged rocks, washed into gullies by the sea, which plays through them almost incessantly. everything had to be thought of and provided for beforehand; even so small a matter as the want of a little clay for tamping holes might have stopped the work for a time. piers were built at mull where the granite was quarried, and all sorts of conveniences and contrivances for the vessels and tug in use. the poor workmen suffered dreadfully from seasickness when compelled to live on their vessel, so they erected a temporary wooden barrack on the rock, but it was completely swept away in a november gale, destroying the work of a season in a single night. the dauntless men went to work again, however, and built another shelter which stood so successfully that it was finally taken down several years after the light-house was completed. alan stevenson tells us of their life in this wave-washed eyrie, where he was perched forty feet above the sea-beaten rock with a goodly company of thirty men, where often for many a weary night and day they were kept prisoners by the weather, anxiously looking for supplies from the shore. at such times they were generally obliged to stay in bed, where alone they found an effectual shelter from the wind and spray which searched every cranny in their walls. more than once the fearfulness of the storm drove the more timid from their frail abode, which the sea threatened to overwhelm, out on the bare rock where the roofless wall of the light-house offered a safer defence against the perils of the wind and waves. innumerable were the delays and disappointments which tried the courage and faith of stevenson and his brave band. it was a good lesson in the school of patience, and they learned to trust in something stronger than an arm of flesh. more than once their cranes and materials were swept away by the waves, and the workmen left, desponding and idle. they incurred daily risks in landing and in blasting the splintery gneiss, and in the falling of heavy bodies in the narrow space to which they were confined. for all, they met with no loss of life or limb, and maintained good health in spite of being obliged to live on salt provisions for six summers. but the hardships and responsibilities by no means end with the building of the light-house; the keeper who has it in charge holds a most important position, for upon the skill of his hands in the management of the delicate costly lenses and machinery, the clearness of his head, and the courage of his heart, as well as his honesty and fidelity, depends, even more than upon the captain of a vessel, the safety of many precious lives and millions of property; so it is of the first importance that he be intelligent, efficient and trustworthy. a light which has been visible for years cannot be suffered to be extinct for one hour without endangering a vessel's safety. the failure to illuminate at the proper time might prove fatal to the confiding mariner. in england it is a situation for life unless the holder prove unworthy, with a pension if superannuated; but in our own country the appointments are in a measure political, and consequently liable to be temporary. this circumstance is deplored by the board which sometimes in this way loses valuable servants after they have gained a skill and experience which only comes with time; and raw, untried hands have to be placed in positions of trust. it is hoped that some change will soon be brought about in this matter. [illustration: first class light-ship, with steam fog whistle.] a year or more ago a gentleman, who holds an important position in the office of the light-house board and is specially interested in the comfort and welfare of the keepers, came in the course of a tour he was making on one of the supply ships, which carry half-yearly stores to the different posts, to a very isolated light-house off the florida coast, twenty miles from any human habitation and sixteen from _terra firma_. just before the arrival of the vessel a little child of the keeper had died, and was about to be buried in the sea without so much as a word of prayer being said over it. mr. ---- was shocked to find that these poor people in their isolation seemed to have no idea of religion, and that there was not a book of any kind at the station. the parents made no objection to his reading the burial service over the poor baby, out of a little prayer-book which he happened to have in his pocket, and he went away determined to do his part towards making good the deficiency he had discovered; for on investigation it was found that very many light-houses were quite as much cut off from books as the one he had visited, and one instance had occurred of a poor fellow who had actually gone crazy, from sheer mental starvation, in his loneliness. many persons have interested themselves in mr. ----'s scheme. an appropriation has been asked from congress for supplying reading matter to the six hundred and more light-houses along our coast; and in the mean time private individuals have sent in contributions in the way of old books and magazines. the lady and gentlemen clerks at the light-house board have been most kind and helpful in the matter; for they always feel an interest in the condition of the keepers and their families, and when cases of suffering come to their knowledge, as lately, when a keeper at the south was burnt out and lost all his possessions, are prompt with their assistance. in this instance they helped to sort and arrange the motley piles of donated literature, which was then bound up nicely, in uniform volumes, at the government printing office, and a neat little library-case of strong oak wood was made, fitted up with shelves and having heavy metal clasps and handles; and just so many volumes, always including a bible, were placed in each case. the store-ships will now go out with a goodly lading of these supplies; one will be left at each station, and the next time the ship comes round the old case will be taken away and a fresh one substituted. in this way a circulating library system is established, and every keeper well supplied with abundance of wholesome and entertaining reading matter. you children, with your wealth of books and delightful magazines coming every month, can perhaps hardly appreciate the boon this kind thought, so well carried out, will prove; for you have never known what it is to be shut up in a lonely tower, day after day, month after month, with no outside interest or amusement. you can do your part towards brightening the lives of these men with their wives and children, and i am sure you will be glad of the opportunity. many of you, no doubt, have piles of old magazines or story papers, or even of books, for which you have no further use. would you not like to put up a nice package of these, and send them by express to the "care of the chief clerk of the light-house board, washington, d. c."? new supplies are constantly needed, and in this way you could not fail to give pleasure to those who have little enough in a life of monotonous duty. "buy a broom! buy a broom!" last summer while on our vacation trip along the sea-coast we made our plans so as to stop over a train at barnstable that we might have time to take a look at that ancient burgh, but found to our dismay when it was too late, that of _time_ we had altogether too much, for when we stepped out of the car it was seven o'clock in the morning, and our train would not leave till four in the afternoon! and to make matters worse it began to rain. we managed, however, at intervals when the rain held up, to get a pretty good idea of the place, but were driven back to the station by the persistent drizzle long before noon; and there we seemed destined to spend five tedious hours, with not much of anything to do, except to get the way-bills of the old colony railroad by heart, and commit to memory whatever might be available in the other advertisements posted on the walls. [illustration: the blind broom-maker of barnstable.] we were beginning to be desperate, when my companion, strolling about, discovered a small placard saying that fruit was for sale in the freight depot. i set out to explore, having visions of apples and pears, but especially peaches and grapes before me. passing the wide freightage doors, i came to a narrow one which was wide open; so i first looked, and then walked in. it was an unfinished place where a slim young woman was busy about her housework, while a sick-looking man was "standing round." there was a cooking-stove, and she was taking pies out of the oven, which she set in a row on a cumbrous wooden bench that filled all the opposite end of the room, and under it were stored bunches of something unknown to me which i found afterwards was broom-corn. she was pretty and girlish, and had blue eyes, and fair hair. she asked me to sit down, and told me they had been living there off and on for three years. "we used to live in 'commons,' but we did not like, and so came up here. my husband is not well, and i go out washing, and take in washing." it was a very queer place to live in, but neat and comfortable, yet it seemed just as if they might have been moving, and had merely stopped here over night and set up their stove in order to cook something to eat. upon inquiring for the fruit, about which it began to seem as if there must be either a mistake or a mystery for nothing of the kind was to be seen except the dish of apples left over from the pies, she directed me up-stairs; and up the steep narrow stairs i went, nearly stumbling over a great black dog (which she assured me would not bite) that lay stretched at the threshold of a dreary kind of room which had one occupant--a man with his shirtsleeves rolled up to the elbows at work near one of the windows at the farther end. and now i remembered that we had seen him at his bench there as we sat in the depot, and wondered what he was doing. [illustration: a gay cavalcade.] no indications of fruit; but there were four machines and a stack of brooms, and the litter of shreds and waste, and i was about to retreat with an apology after making known my errand. he said i had made no mistake, but he was out of everything except confectionery; peanuts, dates and figs. so as there were no apples, no pears, no peaches, no grapes, after all my perseverance, _dates_ i would have, and he went to a closet where he said he kept them, holding his hands out before him in such a way that i knew he could not see even before he said, "i am blind." after he had weighed them and received his pay, there were a few words about his business, which he seemed delighted to talk about, and because i put a question or two, he asked if i was a reporter, and said "that used to be my business. i was on the reportorial staff of the pennsylvania legislature, when from overtasking my eyes, and other causes, i became blind. i went to the institution at south boston, and learned to make brooms so that i could earn my living." he was full of interest in the work he had been compelled to fall back upon, and invited me to come in with my companion and see how it was done. "now i wish," said he, "that i had some stuff ready. i have to soak it before i use it. but your train does not go till four o'clock. i will put some to soak immediately, and if you will come in about three i will begin at the beginning and make a broom, so that you can then see the whole process." to be sure we were glad to go, and he did as he said he would, and explained every particular, even to the cost. "the broom-corn comes from the west," he said, "though a good deal grows in the mohawk valley, and the largest broom establishment in the united states is at schenectady. "it often grows, if thriving stalks, ten or twelve feet tall; it can be cultivated here, but not so profitably. it comes in large bales, weighing anywhere from one hundred and fifty to five hundred pounds. where i buy mine in boston it costs me six cents a pound, though the price varies. "i sort it out on a 'sorting bench,' first, for if i took it as it is, the brooms would be of queer qualities. sorting is a regular trade to learn. "the next thing, i tie it in bundles, and then it is ready for use. i put as many of these to soak the night before, as i want to make up in the day. i leave it in the water half an hour, then let it drain, and it keeps damp enough for working; if it was dry it would break when i sew it. here you see this lot, from which i shall make the broom. i call now we have wire, and it is galvanized to prevent it from rusting. it costs me twelve cents a pound; it used to cost seventeen." [illustration: the comedy of brooms--mamma's little housemaid.] having made the handle fast, he took a bunch of the corn, smoothed it carefully through his hands to even it, laid it against the handle, put his foot on the treadle or whatever the hour-glass shaped piece of mechanism might be named, and with one or two revolutions wired it tight. this lot had the butts left on, but from the next layer he sliced them down wedge-fashion with a very sharp knife, having secured them to those already on by a strap which could be fastened at such length as he chose by means of a leather button; another and another tier, each time of choicer quality, succeeded, and so on till the stock for that broom was used up. "this," he explained, "is a number eight broom. if there had been time i would have made a _hurl_ broom, which is the best. (the 'hurl' is the finest part of the corn, the heart.) i make five sizes: number six is the smallest, and it is the smallest manufactured in this country. i can make twenty of those in a day. of the number ten, the hurl, i have made twelve, and they sell for forty cents apiece. sometimes when i have got a lot of brooms on hand i hire a horse and cart, take a boy with me, and go round the country to sell them; and people will object to paying my prices, and i can't always make them believe that it pays to buy a good article, even if it is a broom. they sometimes say that they can get enough of them at fourteen cents, but i tell them when they pay fourteen cents for a broom, they only get a fourteen-cent broom." [illustration: up in the attic.] he had now a rough broom, which he released from the vise and took over to the press which had three pairs of cruel-looking irons that he said were "the jaws," of sizes to shut round brooms of three different thicknesses and hold firmly, while he did the next thing, which he made known in this wise: "now i shall sew it. the number six have only two sewings--all they need, they are so thin. the others have three. they are all sewed with waxed linen twine: the higher sizes have pink, because it looks better; the others have tow-colored. you see my needle? it is some like a sail-maker's, but not exactly. i have two, though one will last a lifetime. i keep them in this oiled rag to prevent them from rusting. they cost fifty cents apiece, and were made of the very best of steel. see what nice metal it is!" he held out one, shaped more like a paddle than anything else, polished to the last degree, and as lustrous as silver; then he threw it on the floor to show us how it would ring. "broom tools of all kinds are made at schenectady, but my needles, knives and combs come from hadley. i will show you the combs pretty soon; the knives you have already seen. let me see--where did i lay that other needle? no, you need not look for it; i must find it myself. i have to be careful where i leave my things, so that i can put my hand on them the moment i want them. oh, here it is," picking it up with his long supple fingers, and rolling it securely up in the oiled cloth. "now you notice i put on this _palm_," and he held up what looked like a mitt just large enough to cover the palm of the hand and the wrist, having a hole to slip the thumb through and leaving that and the fingers free. it was made of cowhide, and sewed together on the back, while in the inside was set a thimble against which the needle was to be pressed in doing the hard sewing, while the leather protected the skin from being fretted by the broom. "it is not just like a sail-maker's palm," he added. "i have one of those which a man gave me, and i will show it to you." so going again to his dark closet, he groped for it among his multifarious things, and came back with one similar, except that it was of raw-hide, and the thimble was a little projection looking like a pig's toe. [illustration: "plant the broom!"] he sewed the broom through and through, producing the three pink rows. then he said he would comb it to clear away the loose and broken stems; and so he passed through it a sort of hetchel made of thirty small knife-blades set in a frame, "which cost me," said he, "more than you would think--that comb was five dollars; and now i comb it out with this one to remove the small stuff and the seeds." and releasing it from the clamp, he took down a fine comb from a nail, and repeated the process. "and now it is ready to be trimmed. i lay it on this hay-cutter, which some friends bought cheap for me at a fair, and answered my purpose after a few alterations, and i trim it off, nice and even at one end--and now it is done. you have seen a broom made." that was true. our only regret was that we could not have that same broom to take away; but on our zig-zag journey, when we were likely enough to stop over or turn off anywhere, that was an absurdity not to be thought of. we did, however, "buy a broom" that we _could_ take--and an excellent one it proved--and we accepted a small package of broom-corn seed which the blind workman was anxious we should have, "to plant in some spare spot just to see how it looks when growing." when we went down-stairs, the woman was out on the platform, her yellow hair tossing about in the wind, and she seemed as happy with her meagre accommodations in the freight house as if she were owner of a mansion. she begged us to go in and get some of her apples, we were welcome, and "they did not cost me anything," she added. she told us more about her fellow-tenant, and said he paid half the rent, "and he used to board with us, but now he boards up in town, and he goes back and forth alone, his self." * * * * * this curious and pleasant little episode made us so ready to be interested in everything pertaining to brooms that it seemed a kind of sarcasm of circumstances when, at a junction not very far along our route, we saw, perched upon his cart, a pedler doing his best to sell his brooms to the crowd on their way home from one of the cape camp-meetings. his words were just audible as the train went on: "buy a broom! buy a broom! here's the place to buy a cheap broom, for _fourteen_ cents! _only_ fourteen cents! a broom for fourteen cents! so cheap!" and it happened not many days later that somebody read in our hearing that the broom-corn is a native of india, and that dr. franklin was the means of introducing it into this country; from seeing a whisk of it in the hands of a lady he began to examine it--being of an inquiring mind, as everybody knows--and found a seed, which he planted. the street-sweeper's broom is the genuine _besom_, made of birch stems, cut out in the country, and brought into town tied up in bundles like fagots; suitable enough for those stalwart men who drag them along so leisurely, but burdensome for the hands of the wretched little waifs, who, tattered and unkempt, make a pretence of keeping the crossings clean; who first sweep, and then hold out a small palm for the penny, dodging the horses' hoofs, and just escaping by a hair's breadth the wheels of truck or omnibus in their attempts to secure the coin, if some pitiful passer-by stops at the piping call: "please ma'am, a penny!" that is the almost tragic prose of brooms. [illustration: the tragedy of brooms--the crossing sweeper.] but there is a bit of poetic history that ought not to be forgotten, for it was a sprig of the lovely broom bush--call it by the daintier name of heath if you will--such as in some of its varieties grows wild in nearly every country in europe, a tough little flowering evergreen, symbol of humility, which was once embroidered on the robes, worn in the helmet, and sculptured on the effigies of a royal house of england. which of the stories of its origin is true, perhaps no one at this distant day can determine; but whether a penitent pilgrim of the family was scourged by twigs of it--the _plantagenesta_--or a gallant hunter plucked a spray of it and put in his helmet, it is certain that the humble plant gave the stately name of "plantagenet" to twelve sovereigns of that kingdom; and their battle-cry--which meant to them conquest and dominion, but has a very practical sound to us, and a specially prosaic meaning to one like the blind broom-maker of this simple story--was this: "_plant the broom! plant the broom!_" talking by signals. when boys live some distance apart, it is pleasant to be able to communicate with each other by means of signals. many and ingenious have been the methods devised by enthusiastic boys for this purpose. but it can be brought much nearer perfection than has yet been done, by means of a very simple system. at the age of fourteen i had an intimate friend who lived more than a mile away, but whose home was in plain sight from mine. as we could not always be together when we wished, we invented a system of signalling requiring a number of different colored flags; but we were not quite satisfied with it, for we could send but few communications by its use. then, when we came to test it, we found the distance was too great to allow of the different colors being distinguished. the white one was plainly visible. it seemed necessary, therefore, that only white flags should be used. we studied over the problem long and hard, with the following result. we each made five flags by tacking a small stick, eighteen inches long, to both ends of a strip of white cloth,[b] two feet long by ten inches wide. then we nailed loops of leather to the side of our fathers' barns, so that, when the sticks were inserted in them, the flags would be in the following positions: the upper left hand position was numbered , upper right , lower right , lower left , centre . notice, there was no difference in the _flags_; the _positions_ they occupied determined the communication. thirty combinations of these positions can be made: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- . these combinations were written down; and opposite each was written the question or answer for which it stood. the answers likely to be used most we placed opposite the shortest combinations, to save time in signalling. my old "code" lies before me, from which i copy the following examples: . _yes._ . _no._ . _morning._ . _afternoon._ . _evening._ . _can you come over?_ . _when?_ . _wait till i find out._ . _can you go a-fishing?_ . _are you well to-day?_ suppose, now, that i place flags in positions and . (see the above examples.) harry glances down his "code" until he reaches and its signification, and perhaps answers with a flag at . then the following dialogue ensues: i. . he. . i. . he. . and, in a few moments, he. . we usually spent our noon hour conversing with each other in this manner; and, when it became necessary for either to leave his station, all the flags, , were put out, signifying "gone." one combination, , was, by mutual consent, reserved for a communication of vital importance, "come over!" it was never to be used except in time of trouble, when the case would warrant leaving everything to obey the call. we had little expectation of its ever being used. it was simply a whim; although, like many other things, it served a serious purpose in the end. not far from my father's house stood a valuable timber lot, in which he took an especial pride. adjoining this was an old apple-orchard, where the limbs of several trees that had been cut down, and the prunings of the remainder, had been heaped together in two large piles to be burned at a favorable opportunity. one afternoon, when there was not the slightest breath of wind, we armed ourselves, father and i, with green pine boughs and set the brush-heaps a-fire. we had made the heap in as moist a spot as possible, that there might be less danger of the fire spreading through the grass. while the flame was getting under way, i busied myself in gathering stray bits of limbs and twigs--some of them from the edge of the woods--and throwing them on the fire. "be careful not to put on any hemlock branches!" shouted my father from his heap. "the sparks may snap out into the grass!" almost as he spoke a live coal popped out with a loud snap and fell at my feet, and little tongues of flame began to spread through the dead grass. a few blows from my pine bough had smothered them, when snap! snap! snap! went three more in different directions. as i rushed to the nearest i remembered throwing on several dead hemlock branches, entirely forgetting their snapping propensity. bestowing a few hasty strokes upon the first spot of spreading flame, i hastened to the next and was vigorously beating that, when, glancing behind me, i saw to my dismay that the first was blazing again. ahead of me was another, rapidly increasing; while the roaring, towering flame at the heap was sputtering ominously, as if preparing to send out a shower of sparks. and, to make matters worse, i felt a puff of wind on my face. terror-stricken i shouted: "father! the fire is running! come quick!" in a moment he was beside me, and for a short time we fought the flame desperately. "it'll reach the woods in spite of us!" he gasped, as we came together after a short struggle. "there isn't a neighbor within half a mile, and before you could get help it would be too late! besides, one alone couldn't do anything against it!" a sudden inspiration seized me. "i'm going to signal to harry!" i cried. "if he sees it he'll come and, perhaps, bring help with him!" "hurry!" he shouted back, and i started for the barn. the distance was short. as i reached it i glanced over to harry's. there were some white spots on his barn. he was signalling and, of course, could see my signal. excitedly i placed the flags in , and, without waiting for an answer, tore back across the fields to the fire. it was gaining rapidly. in a large circle, a dozen rods across, it advanced toward the buildings on one hand and swept toward the woods on the other. we could not conquer it. we could only hope to hinder its progress until help should arrive. [illustration: in obedience to the signals.] fifteen minutes of desperate struggle and then, with a ringing cheer, harry and his father dashed upon the scene. their arrival infused me with new courage; and four pairs of hands and four willing hearts at length conquered the flame, two rods from the woods! my father sank down upon a rock, and, as he wiped the perspiration from his smutty face, he said: "there, boys, your signalling has saved the prettiest timber lot in the town of hardwick! i shall not forget it!" were we not justly proud? two days after i found upon my plate at breakfast a small package, which contained two pretty little spy-glasses. "perhaps they will enable you to enlarge your 'signal code,'" was all my father said when i thanked him. we soon found that with the aid of the glasses we could distinguish any color. so we made a set of blue flags, which gave us thirty more communications by using them in place of the white ones. and, by mixing the blue flags with the white combinations and the white with the blue combinations, over _two hundred_ communications could be signalled. thus we could converse with each other by the hour. the way we wrote down the mixed combinations was, by using a heavy figure to represent a blue flag; as [ ] [ ], which meant that positions and were occupied by white flags, and by blue ones. blue flags can be inserted in the original thirty combinations in the following manner: [ ], [ ], [ ], [ ], [ ], [ ] [ ], [ ] , [ ], [ ], [ ], [ ], [ ] , [ ] , [ ] [ ], [ ] , [ ], [ ], and so on. among the many recollections that throng my memory in connection with this subject, is that of an incident which has caused me many a hearty laugh since its occurrence, although at the time i did not feel particularly amused. harry had gone away visiting, giving me no definite idea of when he would return. so, one drizzling, uncomfortable day, as i was sitting rather disconsolate at my barn window, i was delighted to see several flags appear on his barn. eagerly i read: . "_can you go a-fishing?_" the fine drizzling rain was changing into larger drops, and there was every reasonable prospect of a very wet day, and i thought he must be joking; but i answered: "_when?_" "_now_," was the reply. "_where?_" i asked. "_bixbee's pond._" "_are you in earnest?_" "_i will meet you there._" i answered "_yes_," and, shouldering my fish-pole, started off across-lots. the distance was fully a mile and a half, and before i had passed over a quarter of the distance the bushes, dripping with rain, had completely drenched me. when nearly there the increasing rain became a heavy shower; but i kept on. i reached the pond, but nothing was to be seen of harry. not a frog could i find for bait, owing to the incessantly pouring rain, and i knew it would be difficult to find a worm. so, after half an hour of tedious waiting and monotonous soaking, i started for harry's, my patience entirely worn out. the rain came down in torrents as, at length, i turned in at the gate; and i suppose i looked as forlorn as a drenched rooster, for i heard a girlish giggle as i stepped upon the piazza, but i did not then suspect the truth. "where's harry?" i asked of his mother whom i found alone. "why, you didn't expect to find him at home, did you? he won't be back for a number of days yet." (another subdued giggle from the next room.) "you're as wet as a drowned rat!" went on the motherly woman. "what on earth started you out in this rain?" "it's that hattie's work!" i burst out angrily, and told her the whole story. "dear me!" she exclaimed, holding up her hands, despairingly, "i never did see such a torment as that girl is! i noticed she has seemed very much tickled over something! i'll give her a real scolding!" i darted out the door; and, as i splashed my way disconsolately down to the road, i heard a voice, struggling between repentance and a desire to laugh, call after me: "forgive me, charlie, but it was _such_ a joke!" hattie never meddled with her brother's signals again. for her mother's displeasure and the severe cold that followed my drenching more than balanced the enjoyment she derived from that very practical joke. * * * * * two years ago i visited my native town. resuming my old place by the barn window, i gazed across the intervening forest to where harry used to stand and signal to me. tacked up against the window-sill was my old "signal code," covered with dust and cobwebs. harry was hundreds of miles away, carving himself a name among his fellow-men. of all the friends of former days, scarcely one remained in the old town. and i could only wish, with all my heart, that i were once again enjoying my boyhood's happy hours. ----- [b] if the buildings should be painted, the flags should be of a color that would contrast with that of the paint. jennie finds out how dishes are made. ah! i know something! i know something you girls don't know! i know how they make dishes what you eat off of; and it's just the same way they make dolly's dishes, i guess. yes, i _do_ know. and i've got some pictures papa _drawed_ for me, too, and i'll tell you all about them. they're in my pocket right under my handkerchief. i put them under my handkerchief because i don't want them to get dirty. i've got some 'lasses candy on top. i haven't got enough, or i'd give you all some. papa took me to a _pottery_. i don't know why they call it a pottery, for they make cups and saucers, and sugar-bowls, and everything. first the man took us through the _dressing-room_. i did not see any dresses, nor anybody dressing themselves. i only saw piles of dishes and men and women hammering at them. i asked papa why they called it that, and he said, wait till we come back, for that was the very last of all. so we went on into the yard. i looked into one part of the building where it was all dark, with three great chimneys, broad on the ground and narrow high up. but the man and papa went right on, round to the other side of the building. there wasn't anything to see, though, but horses and carts hauling clay, and great heaps of it on the ground. i wouldn't have called it anything but dirt, but papa said it was _kaolin_, not exactly dirt, but clay. he spelt it for me. there was another of those big chimneys in the yard, only bigger. the man said that was where they dried the clay. then he led us to a little door in the side of the house, and we went in. that brought us into a little room where they were getting the clay ready. first there was a sand-screen--like mike uses, where they sieved it. next they weighed it and put it into bins. it looked like fine, dark flour. [illustration: the potter's wheel.] a little piece off from the bins there was a big deep box. they were mixing clay and water in it, and making a paste. it looked like lime when they're making mortar. the box leaked awfully, and white paste was running down on the floor. at the end of the box they had a pump working, and it was pumping the paste into what they called a _press_. it was too funny for anything. i couldn't more than half understand it. but it looks something like a baby-crib, only it has slats across the top, and they're close together. they have a lot of bags inbetween the slats, and the clay gets into the bags and gets pressed flat, so that most of the water is squeezed out. when they take it out of the bags it looks something like a sheet of shortcake before it's cut or baked. then they roll a lot of them together, and that's what they make dishes out of. they call it _biscuit_. the man took us down into the cellar under the little room to show us the engine that made the paste and pumped and pressed the clay. i was afraid, and didn't want to go down, but papa said it was only a little one. it was nice and clean down there, with a neat brick floor, but awful hot. i was glad to come up. [illustration: the kiln and saggers.] after the little room there's one big room where they don't do much of anything. it is like a large shed, for it is dark and has no floor. the dressing-room where we were first is on one side, and the dark room where the big chimneys are, is back of it. we went through it, and over to one side and up the stairs to the second story. it's nice up there. it's one great big room, five times as big as our sunday school room, with ever so many windows. all around the sides and down the middle, and cross-ways, and out in the wings are shelves, piled full of brand-new dishes. and there are tables all along the walls, and that's where they make them. i could stand and look all day. i saw two boys throwing up a great big lump of clay and catching it; then cutting it with a string and putting the pieces together again, then throwing it up again, until it made me dizzy to look at them. i asked the man what they were doing, and he said, _wedging the clay_. that means taking the air out. they keep on doing that until there are no air-bubbles in it. we stopped and talked to a man who was making a sugar-bowl, and he told us how he did it. all the men have on the table in front of them a lump of clay, a wheel, some moulds, a sharp knife, a bucket of water with a sponge in it, and something like the slab of a round, marble-topped table, only it's made of plaster paris, to work on. [illustration: mould for a cup.] and do you know what the potter's-wheel is? it's as old as the hills and it's in the bible, but i guess everybody don't know what it is. it looks as if it was made of hard, smooth, baked white clay, and is something like a grindstone, only not half as thick. the grindstone stands up, but this lays flat, with its round side turned up, like the head of a barrel. and it's set on a pivot, like the needle of the compass in our geographies. the moulds are like miss fanny's wax-fruit moulds. they're made of plaster paris, and they're round outside, and they have the shape of what the man wants to make on the inside, and they're in two pieces. little things like cups are made in one mould; but big things like pitchers are made in two or three pieces, in two or three moulds, and then put together. handles and spouts and such things are made separately in little moulds and put on afterwards. [illustration: handle mould.] here's the way. first the man cuts off a piece of the biscuit, and kneads it on the plaster paris slab. then he takes one piece of the mould, fixes the clay in nicely, shaves off what he don't want, then puts on the other piece of the mould, and sets it on the wheel. he gives it a shove and sets it spinning. it stops itself after a while, then he opens the mould, and there is the dish. the clay keeps the same thickness all through, and fills both pieces of the mould. [illustration: making a sugar-bowl.] then the man takes it out and sponges it. if it isn't just the right shape all he has to do is wet it, and it will come right. then he puts on the handle or puts the pieces together, fixing them just so with his fingers and knife. it isn't very hard, but he has to be careful. the soft dishes look real cute. then they're ready to be burnt the first time. we walked all around and saw here one man making cups, another, tureens, another, bird-baths, and every imaginable thing that is ever made in porcelain. then we went down-stairs, through the dark rooms, into where the tall chimneys are. then i found out they called them _kilns_. they have at the bottom a prodigious furnace, over that a tremendous oven, where they put the dishes in to bake. but they don't put them right in just as they are. oh, no. there were on the high shelves all around, a lot of things called _saggers_. they look something like bandboxes made of firebrick. the soft dishes are put in them, the lids are put on, and then they are piled up in the oven. then the men build a big fire in the furnace, and let it burn for several days. when it goes out they let several more days go by for the kiln to cool, and then take out the saggers. when the dishes are taken out they are hard and rough and of a yellowish white. they build the fire after they get them in, and let it out and the kiln cool off before they take them out, because the men have to go in and out the big ovens. wouldn't you think a pile of soft plates and saucers would burn all together and stick fast to each other? well, they don't. there are little things made of hard clay with three bars and three feet, and they put them in between dishes so that one plate has one in it, and the next plate sets on top of that, so that they can't stick together. did you ever see three little dark spots on the bottom of a saucer? this is what makes them. there are lots and lots of these little stands lying all around everywhere, and broken pieces of them and the clay, scattered like flour all over the ground and floors thick. we next went into the room back of the kilns. it had shelves all around, too, and there were piles of dishes after the first burning. a lot of women sat on stools on the floor and they were brushing the fire cracks with some stuff out of little bottles. this was to fill them up so that the glazing wouldn't run in. [illustration: rest for flat dishes.] we went into another room at one side of the first and there's where they did the glazing. they called it _dipping_. there was a large tank in the middle of the room with a deep red liquid in it. papa asked the man what it was, and he said it was a secret preparation. the men dipped the dishes in, and they came out a beautiful pink, so pretty that it seemed a pity they couldn't stay so. there were shelves all around this room, too, and there the dishes look like they do when we see them--the pink glazing has turned white. there is nothing more done to them except the _dressing_. we had now gone all around, and were almost at the _dressing-room_ where we started. and when we went in again we found that the dressing was nothing but knocking off any rough lumps with a chisel. i remember every bit of it. and every time i look at dishes i think there are ever so many things we use every day and don't know anything about. archery for boys. mr. maurice thompson has excited all the grown-up boys who loved in their younger days to draw the bow, by his graceful articles on archery for young men and women. [illustration: fig. a.] i want to tell the boys who are wide awake how they may, without too much labor and with but little expense, make their own bows and arrows and targets, having _their_ fun, like their elders, in this health-giving and graceful recreation. in the first place, after you have made your implements for the sport, you must never shoot at or towards anyone; nor must you ever shoot directly upwards. in the one case you may maim some one for life, and in the other you may put out your own eye as an acquaintance of the writer's once did in virginia. to make a bow take a piece of any tough, elastic wood, as cedar, ash, sassafras or hickory, well-seasoned, about your own length. trim it so as to taper gradually from the centre to the ends, keeping it flat, at first, until you have it as in this sketch--for a boy, say, five feet in height: (fig. a) this represents a bow five feet long, one and a quarter inches broad in the middle, three-fourths of an inch thick at the centre, and a half-inch scant at the ends in breadth and thickness. bend the bow across your knee, pulling back both ends, one in each hand, the centre against your knee, and see whether it is easily bent, and whether it springs readily back to its original position. if so your bow is about the right size. cut near each end the notch for the string as in this figure: (fig. b.) [illustration: fig. b.] bevel the side of the bow which is to be held towards you, so that a section of your bow will look like this figure: (fig. c.) [illustration: fig. c.] the back or flat part is held from you in shooting, and the bevelled or rounded part towards you. scrape the bow with glass and smooth it with sand-paper. to shape your bow lay it on a stout, flat piece of timber, and drive five ten-penny nails in the timber, one at the centre of your bow, and the others as in figure below, so as to bend the ends for about six inches in a direction contrary to the direction in which you draw the bow: (fig. d.) [illustration: fig. d. (a and b are six inches from the ends. the bow is bent slightly at c.)] your bow is now finished as far as the wood-work is concerned, and you may proceed to wrap it from end to end with silk or colored twine, increasing its elasticity and improving the appearance. the ends of the wrap must be concealed as in wrapping a fish-hook. glue with spaulding's glue a piece of velvet or even red flannel around the middle to mark your handhold. the ends may in like manner be ornamented by glueing colored pieces upon them. a hempen string, whipped in the middle with colored silk, to mark the place for your arrow nock to be put, in shooting, will make a very good string. for arrows any light, tough wood, which splits straight, will do. i use white pine, which may be gotten from an ordinary store-box, and for hunting-arrows seasoned hickory. these must be trimmed straight and true, until they are in thickness about the size of ordinary cedar pencils, from twenty-five to twenty-eight inches in length. they must be feathered and weighted either with lead or copper, or by fastening on sharp awl-points or steel arrow-points with wire. i used to make six different kinds; a simple copper-wrap, a blunt leaden head, a sharp leaden head like a minie bullet, an awl-point wrapped with copper wire and soldered, and a broad-head hunting-arrow. to make a copper wrap, wrap with copper wire the last half-inch of the arrow until you get near the end, then lay a needle as large as your wire obliquely along the arrow as in this figure: (fig. e.) continue the wrapping until you have weighted the arrow sufficiently; draw out the needle and thrust the end [illustration: fig. e.] of your wire through the little passage kept by the needle, and draw it tight thus: (fig. f.) [illustration: fig. f (before wrap was drawn through.)] [illustration: fig. g. (after wire was drawn through.)] a blunt leaden head is made by pouring three or four melted buck-shot into a cylinder of paper, wrapped around the end of the arrow, slightly larger at the open end, and tied on by a piece of thread. the wood of the arrow must be cut thus: (fig. h.) [illustration: fig. h.] the paper is put on thus: (fig. x.) [illustration: fig. x.] it should look like this after the metal has been poured in and the paper all stripped off. (fig. i.) [illustration: fig. i.] it should look like this after being sharpened like a minie bullet: (fig. j.) [illustration: fig. j.] an awl-point arrow is made by inserting the point in the end of the arrow, wrapping with copper wire, and getting a tinner to drop some solder at the end to fasten the wire and awl-point firmly together. the awl-point looks like this: (fig. k.) [illustration: fig. k.] the awls (like fig. l.) are filed like this into teeth-like notches on the part going into the wood, and roundly sharp on the other part thus: (fig. m.) [illustration: fig. l.] [illustration: fig. m.] these may be shot into an oak-tree and extracted by a twist of the hand close to the arrow-point. [illustration: fig. n.] the broad-head hunting-point (fig. n.) is put on by slitting the arrow and inserting the flat handle of the arrow point, and wrapping it with silk, sinews, or copper wire. these points can be sharpened along the line a b on a whetstone, and will cut like knives. the hunting arrow looks like this: (fig. o.) [illustration: fig. o.] to feather an arrow you strip a goose feather from the quill and, after clipping off the part near the quill-end, you mark a line down the arrow from a point one inch from the nock and, spreading some spaulding's glue along that line apply the feather, lightly pressing it home with forefinger and thumb. after you have glued on one piece lay aside the arrow and fix another, and so on until the first is set, so that you may put on another piece. when you have fastened these feathers on each arrow lay them aside for ten or twelve hours. the three feathers will look like this: (fig. p.) [illustration: fig. p.] a boy can hardly make a good quiver unless he were to kill some furred animal and make a cylindrical case such as the indians have, out of its skin. i am afraid that he usually would have to get a harness-maker to make him a quiver out of leather, somewhat larger at the top than at the bottom. it should hold from eight to twelve arrows. a good target may be made of soft pine, circular or elliptical in shape. in the latter case a line-shot might count, even though it were farther from the centre. pieces should be tacked to the back of this target at right angles to the grain of the wood. differently-colored circles or rings, a little more than the width of an arrow, must be painted on this, with a centre twice the width of an arrow. the outer ring counts one, the next two, three, four and so on to the centre, which of course counts highest. by this plan one's score could be told with perfect accuracy. [illustration: the target.] if an arrow struck on a line between number three and four it counts three and a half. anything like this rarely happens. the target is fixed upon an easel formed of three pieces of wood fastened together by a string at the top, and it ought to lean back at the top slightly, away from the archer. the three arrows count seven, nine, ten--twenty-six in all. in target-shooting you should use awl-pointed, wire-wrapped arrows, as they can be easily drawn out of even a wooden target. dolly's shoes. i can't help wondering if any of the little maidens who are having so much comfort with their beloved dolls in these christmas holidays, ever think that _somebody_ must have taken a great deal of pains to dress them up so nicely, and above all, to make the tiny garments and hats and shoes. the doll's _shoes_!--so pretty, so daintily shaped, so beautifully stitched and trimmed, so perfectly, faultlessly finished from heel to toe, the "cunningest things" in all dolly's wardrobe--did it ever occur to the girlie "playing mother," to ask where they came from, and by whose dexterous fingers they were fashioned? she knows well enough that when angelina christina, or luella rosa matilda jennette, has worn these out, there are enough to be bought in the toy shops for twenty-five or thirty cents a pair; _but who makes them?_ that was the question which came into _my_ head one day, and i set to work to find out--doing just what must suggest itself to anybody who wants information, whatever the subject: that is to say, i went to head-quarters, and asked questions. there are two places in boston--one a "shoe and leather exchange," and the other the establishment of an importer and dealer in shoe store supplies, where they furnish doll's shoes "to the trade," as the phrase is: one is on congress street, and the other on hanover; and the proprietors, mr. daniels and mr. swanberg, instead of being amused at my errand, very kindly told me what i wanted to know. some of the shoes are imported, but they are inferior in style to those made in this country--notwithstanding they come from paris, and everything from that place is supposed superlatively choice and to be desired, as you are very well aware. in the united states there is one factory--and but one, so far as i could ascertain--which supplies a large quantity, about fifteen hundred dozens, for the american market, sending them to all parts, and furnishing the toy-stores in chicago and other western cities, as well as new york, philadelphia and boston. this manufactory is at bordentown, new jersey, and has been in existence about twelve years, and the value of stock now sent out is about seven thousand dollars a year; so much money for the wee feet that run on no errands, and save no steps for anybody! the wholesale jobbers of course advance the price, and in the retail stores they are higher yet; so that each tradesman through whose hands they pass has his trifle of profit in helping to shoe the feet of the doll-people. they retail from a dollar and a dollar and a quarter a dozen, to three dollars and seventy-five cents, according to the style. [illustration: dolly's shoes] they "run," as the dealers express it, in twelve sizes; the "common doll's shoes" (which means shoes for common dolls) vary, however, from the class made for wax dolls, which have grades peculiar to themselves, being not only extra full and wider in the soles, but numbering fewer sizes, from one to six only. of the common kind, the slippers and ties run from one to twelve, the others from three, four or five to that number. they come packed in regular sizes, a "full line," as those for children do, or in assorted sizes and styles; in small, square boxes, such as shoe dealers know by the name of "cartoon," which is another word for the french _carton_, meaning simply that they are made of paste-board. the tiniest is not much more than an inch long, but is a perfectly formed and finished shoe on that miniature scale; and the largest is almost big enough for mrs. tom thumb, measuring about four inches, and it could certainly be worn by many a baby you have seen. as for the names, they come in this order:--slippers, ties, ankle ties, balmorals, buttoned boots, polish buttoned, polish eyeletted, and antoinette, which is a heeled, croquet slipper, in which her doll-ship, when engaged in that out-of-door game, can show off her delicate, clocked stockings to advantage. but what shall i say of the variety in color and trimmings? they are in white and crimson, in buff and blue, in scarlet and purple, in rose color and violet, in bronze and silver and gold, everything but black, for dolls don't like black except in the tips of their gay balmoral or polish boots. and the stuff they are made of is such soft material as can only be found in goat and sheep and kid and glove kid, and _skivers_, which is the name for split leather. i strongly suspected that they were all made of scraps left from large slippers and shoes, but, though this is generally the case, some whole skins have to be used because nothing is ever manufactured for real people boots and shoes and slippers for all kinds of dolls, high and low, rich and poor; to walk in, to dance in, to play croquet in, or to stay at home in; to match their costumes, to match their hair, to match their eyes, to suit them if anything on earth _could_ suit. and every doll could be sure about her "size," for the number is stamped on the bottom of the soles; and i must not forget to say that they have also the "trademark," which is the imprint under the number; this "trade mark" is a pair of boots smaller than anything you can think of. now i am coming to the original question--"_who makes them?_" they are made in large quantities during about six months of the year, accumulating in the summer, ready for the trade, which begins in august, and drops off after the first of january, and is over with for that season by march. in those six working months the factory employs about forty women, and they are mostly invalids or old persons who are not able to do anything but light work, and who receive only small wages, because they are not capable of earning much. so they are generally thin, pale hands and slender fingers which patiently and skillfully fit the patterns, and sew the seams, and do the even nice stitching, and dainty ornamentation, which help to make glad the hearts of the many little girls all over the country, who have found a precious doll, all so daintily shod, among the gifts of their merry christmas. [illustration: my dolly! my own little daughter!] a glimpse of some montana beavers. our road passed down along hell-gate river, leaving deer lodge city some eight miles to the left. as one goes down, the country changes, and occasional pines appear along the banks of the stream, and the landscape becomes much more interesting. at one place, where a tiny tributary flows in, a large community of beavers were building a dam. they were not at all afraid of us, and so we leisurely observed the process, wishing to settle the vexed question as to whether beavers do actually do intelligent mason-work. they had already sunk a great deal of brush, together with limbs of trees, and were now filling this wicker-work in with earth and rocks which they procured a little distance above on the opposite bank. a beaver would run up, flatten his tail on the mud near the bank, then another beaver would scrape the earth up and upon the tail of the first, and pack it down. after he had his load complete, the carrier-beaver would swim away rapidly; his tail, with the load of earth, floating on the surface, the swift movement of the animal alone keeping it afloat. the sagacious creature would invariably swim to the right place and dump the load, and then return for another, the stream presenting a scene of great activity, as several of these curious animal-masons were constantly and swiftly passing and repassing each other with their heavy loads. others, the carpenters among them, were at work in the thicket opposite, cutting brush. we saw many large trees which had been cut down by them. the stumps looked as though some boy had chopped them down with a dull axe. it is surprising to reflect upon the pertinacity of these creatures which enables them to gnaw down such immense trees, and the wisdom with which they calculate the direction in which the trees will fall. it is said here that the beavers cut the limbs off from these trees and then sever them into lengths of about three feet each, and after that float them to the center of their pond, sink them to the bottom and fasten them there, where they remain and are used as food during the winter when the pond is frozen over. this is thought to be one of the principal uses of the pond--to provide a pantry which will not freeze. the pond furnishes a depth of water that is always still, and never freezes to the bottom. although, after witnessing this almost human sagacity, we had many compunctions, we concluded to shoot one fine animal for his skin. we shot one through the head. his companions immediately disappeared; and before we could secure our wounded beaver he also had dived beneath the waters of their pond, and although we waited sometime in the vicinity, we failed to discover him again. the inhabitants say it is nearly impossible to kill a beaver with a rifle, and never, on any occasion does the trapper shoot one. how logs go to mill. [illustration: a maine wood-chopper.] all boys and girls know that boards are made of sawed logs, and that logs are trunks of trees. few, however, know with what hardship and difficulty the trees are felled, trimmed and carried from the woods where they grow to the mills where they are made into boards. in the far west, and in the wilds of maine, are acres upon acres, and miles upon miles, of evergreen forests. one wooded tract in maine is so vast that it takes an army of choppers twenty years to cut it over. by the time it is done a new growth has sprung up, and an intermediate one is large enough to cut; so the chopping goes on year after year. the first or primeval growth is pine. that is most valuable. after the pines are cut, spruce and hemlock spring up and grow. most of the men who live in the vicinity of the lake region work in the woods in the winter. they camp in tents and log huts near the tracts where they are felling trees. all day long, day after day, week after week, they chop down such trees as are large enough to cut, lop off the branches and haul the logs to the nearest water. this work is done in winter because the logs are more easily managed over snow and ice. all brooks large enough to carry them, all rivers, ponds and lakes, are pressed into service and made to convey the ponderous freight towards civilization. all along the shores and in the woods are busy scenes--men, oxen and horses hard at work, the smoke from the logging camps curling among the trees. every log has the initial or mark of the owner chopped deep into the wood to identify it. then, when the ice breaks up, the logs are sent down the brooks to the rivers and through the rivers to the lakes. the logging camps are disbanded, the loggers return to their homes, and the river-drivers alone are left to begin their duties. the river-drivers are the men who travel with the logs from the beginning of their journey till they are surrendered to the saw-mills. each wears shoes the soles of which are thickly studded with iron brads an inch long; and each carries a long pole called a "pick-pole," which has a strong sharp-pointed iron spike in the end. this they drive into the wood, and it supports and steadies them as they spring from log to log. their first duty is to collect "the drive." the logs which form "the drive" are packed together and held in place by a chain of guard-logs which stretches entirely around the drive, forming what is called "the boom." the guard-logs are chained together at the ends about two feet apart. the guard is always much larger than the boom of logs, so that the shape of the boom may be changed for wide or narrow waters. at the head of each boom is a raft which supports two large windlasses, each of which works an anchor. on this head-work about thirty river-drivers take up their position to direct the course of the boom. to change its position or shape, ten of the drivers spring into a boat or bateau; one takes a paddle at the bow; eight take oars; and one, at the stern, holds the anchor. they row with quick strokes toward the spot where the anchor is to be dropped, the cable all the time unwinding from the windlass. "let go!" shouts the foreman. splash! goes the anchor overboard. the boat then darts back to the head-works. out spring the men to help turn the windlass to wind the cable in. they sing as they work, and the windlass creaks a monotonous accompaniment as "meet me by moonlight," or the popular "away over yonder," comes floating over the rippling water. [illustration: a river-driver.] meanwhile another bateau has been out with another anchor; and as both windlasses turn, the boom swings toward the anchorage, and thus is so much further on its way. though the men sing as they work, and make the best of their mishaps with jests and laughter, they often carry homesick hearts. in cold and stormy weather their hardships are great, an involuntary bath in the icy water being an event of frequent occurrence. also their work demands a constant supply of strength which is very trying; frequently a head wind will drive them back from a position which it has taken several days to gain, and all the toil of fresh anchorages must be repeated. the most dangerous part of the work is "sluicing" the logs. when the boom reaches the run which connects the lake or river with the dam through the sluice of which the logs must pass, the chain of guard-logs is detached, and fastened in lines along both sides of the run, and the rafts are drawn off to one side and anchored to trees. the river-drivers, armed with their pick-poles, are then stationed along the run, on the dam, wherever they may be needed. the liberated logs now come sailing along, their speed quickening as they near the sluice. when they reach it they dart through, their dull, rapid, continuous thud mingling with the roar of the water. how they shoot the sluice! log after log--two, six, a dozen together--pitching, tossing, struggling, leaping end over end; finally submitting to destiny and sailing serenely down the river toward another lake. meanwhile the river-drivers with their long poles and quick movements, looking not unlike a band of savages, have enough to do, with steady feet, and eyes on the alert. for of all the vast array of logs--and i once saw twenty-four thousand in one drive--not one goes through the sluice but is guided on to it by one or more of the drivers. they often ride standing on the floating logs, conducting this, pushing that, hurrying another, straightening, turning and guiding; and just before the log on which a driver stands reaches the sluice, he springs to another. woe to him if his foot should slip, or his leap fail! he would be crushed among the logs in the sluice, or dashed among the rocks in the seething water. [illustration: "the liberated logs came sailing along."] after all the logs are safely sluiced, the chains of the guards are slipped, the rafts are broken up, and these, windlasses and all, follow the logs. then the boats are put through the sluice. sometimes, when the dam is high, some of the river-drivers go through in the boats--a dangerous practice, this; for often the bateaux have gone under water, entirely out of sight, to come up below the falls, and more than once have lives been lost in this foolhardy feat. [illustration: through the sluice.--a dangerous practice this.] a boom generally passes from three to six dams, and sometimes takes four months to reach the mills. occasionally the logs become jammed in the rivers, and must wait for more water; if this can be supplied from a lake above, the difficulty is easily remedied. in the spring of , a jam occurred at mexico in maine. the logs were piled forty feet above the water and covered an extent of area as large as an ordinary village. this great jam attracted visitors from all parts of the country until the spring freshets of the next year could supply the river with water sufficient to loose them and bear them on their way. ----- at the present time, july, , the jam is still there. i saw the driving and sluicing as i have described it, in may, . it was very interesting.--s. b. c. s. [illustration] scientific american supplement no. new york, april , scientific american supplement. vol. xix, no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. engineering and mechanics.--bridge over the blaauw krantz ravine, cape colony.-- engravings. torpedo ships. the gas engine.--by dugald clerk.--combustion engines.--first cylinder and piston engine.--watt's experiments.--first gas engine.--principles of the gas engine. rapid construction of the canadian pacific railway.--by e.t. abbott. the osgood mammoth excavator.-- figures. capstan navigation on the volga.-- figures. steamboat equipment of war vessels.--with engraving of winch for raising and lowering torpedo boats. improved steam trap.-- engraving. ii. technology.--critical methods of detecting errors in plane surfaces.--by john a. brashear.-- figures. photometric standards.-- figures. bleaching or dyeing yarns and goods in vacuo.-- figure. on the moulding of porcelain.--by chas. lauth.--moulding by pressure of the air.--moulding by vacuum.--drying the moulded pieces.-- figures. photo-tricycle apparatus.-- figure. a photo printing light.-- figure. a new actinometer. astronomical photography. electricity as a preventive of scale in boilers. iii. decorative art.--alphabet designed by godfrey sykes.--an engraving. old wrought iron gate.--an engraving. iv. geology.--the organization and plan of the united states geological survey.--by j.w. powell.--a topographic map of the united states.--paleontology.--chemistry.--physical researches.--statistics.--library.--publications.--general geology.--economic geology.--relation of the general survey to the state survey. v. botany, etc.--the sunflowers.--annuals, perennials, etc.-- engravings. lye's fuchsias.-- engraving. vi. hygiene, etc.--brief sanitary matters in connection with isolated country houses.--by e.w. bowditch. sanitary cooking.--by v.l. oppenheimer. time required to digest different foods. * * * * * the blaauw krantz viaduct in cape colony. this viaduct is built over a rocky ravine on the railway from port alfred to grahamstown, at a height of about ft. from the bottom. its length is ft. in., and the width of the platform is ft., the gauge of the railway being ft. in. the central span of the viaduct is an arch of ft. span between abutments, and about ft. height; the remainder of the space on each side is divided into two spans by an iron pier at a distance of ft. from the retaining wall. these piers are ft. in. high, and carry girders ft. long, balanced each on a pivot in the center. one end of these girders is secured to the retaining walls by means of horizontal and vertical anchorages, while the other end rests in a sliding bearing on the top flange of the arch. [illustration: bridge over the blaauw krantz ravine, cape colony.] [illustration: bridge over the blaauw krantz ravine, cape colony.] in designing the structure the following points had to be considered: ( ) that, on account of the great height above the ground, and on account of the high price of timber at the site, the structure could be easily erected without the use of scaffolding supporting it as a whole. ( ) that, on account of the high freights to port alfred, the quantity of iron in the structure should be as small as possible. ( ) that the single parts of the principal span should be easy to lift, and that there should be as few of them as possible. for this latter reason most of them were made in lengths of ft. and more. the question of economy of material presented itself as a comparison between a few standard types, viz., the girder bridge of small independent spans; the cantilever bridge, or the continuous girder bridge in three large spans; the single girder bridge with one large span and several small spans; and the arch with small girder spans on each side. the suspension bridge was left out of question as inadmissible. a girder bridge with small independent spans on rocker piers would probably have been the most economical, even taking into account the great height of the piers near the middle of the ravine, but there would have been some difficulty in holding those piers in position until they could be secured to the girders at the top; and, moreover, such a structure would have been strikingly out of harmony with the character of the site. on the other hand, a cantilever or continuous girder bridge in three spans--although such structures have been erected in similar localities--could not enter into comparison of simple economy of material, because such a design would entirely disregard the anomaly that the greater part of the structure, viz., the side spans, being necessarily constructed to carry across a large space, would be too near the ground to justify the omission of further supports. the question was, therefore, narrowed to a comparison between the present arch and a central independent girder of the same span, including the piers on which it rests. the small side spans could obviously be left out in each case. the comparison was made with a view not only to arrive at a decision in this particular case, but also of answering the question of the economy of the arch more generally. the following table contains the weights of geometrically similar structures of three different spans, of which the second is the one here described. the so-called theoretical weight is that which the structure would have if no part required stiffening, leaving out also all connections and all wind bracing. the moving load is taken at one ton per foot lineal, and the strain on the iron at an average of four tons per square inch. the proportion of the girder is taken at in . --------------+-----------------------+------------------------+ | theoretical weight. | total weight. | span in feet. +-----------------------+------------------------| | arch. | girder. | arch. | girder. | --------------+---------+-------------+------------+-----------| | . | . | . | . | | . | . | . | . | | . | . | . | . | --------------+---------+-------------+------------+-----------+ |<------------tons per foot lineal.------------->| it can be seen from these results that the economical advantage of the arch increases with the span. in small arches this advantage would not be large enough to counterbalance the greater cost of manufacture; but in the arch of ft. span the advantage is already very marked. if the table were continued, it would show that the girder, even if the platform were artificially widened, would become impossible at a point where the arch can still be made without difficulty. the calculations leading to the above results would occupy too much space to make it desirable on this occasion to produce them. our two views are from photographs.--_the engineer._ * * * * * torpedo ships. commander gallwey lately delivered an interesting lecture on the use of torpedoes in war before the royal u.s. institution, london, discussed h.m.s. polyphemus, and urged as arguments in her favor: . that she has very high speed, combined with fair maneuvering powers. . that she can discharge her torpedoes with certainty either ahead or on the beam when proceeding at full speed. . that her crew and weapons of defense are protected by the most perfect of all armor possible, namely, ft. of water. . that she only presents a mark of ft. above the water line. then, he asked, with what weapon is the ironclad going to vanquish these torpedo rams? guns cannot hit her when moving at speed; she is proof against machine guns, and, being smaller, handier, and faster than most ironclads, should have a better chance with her ram, the more especially as it is provided with a weapon which has been scores of times discharged with certainty at yards. the ironclad, he answered, must use torpedoes, and then he maintained that the speed and handiness of the polyphemus would enable her to place herself in positions where she could use her own torpedo to advantage, and be less likely to be hit herself. he then called attention to the necessity for well-protected conning towers in these ships, and prophesied that if a submarine ship, armed with torpedoes, be ever built, she will be the most formidable antagonist an ironclad ever had; and the nearer the special torpedo ship approaches this desideratum the better she will be. * * * * * a plumbing test. a recent trial of a smoke rocket for testing drains, described by mr. cosmo jones in the _journal of the society of arts_, is deserving of interest. the one fixed upon is in. long, ½ in. in diameter, and with the composition "charged rather hard," so as to burn for ten minutes. this gives the engineer time to light the fuse, insert the rocket in the drain, insert a plug behind it, and walk through the house to see if the smoke escapes into it at any point, finishing on the roof, where he finds the smoke issuing in volumes from the ventilating pipes. the house experimented upon had three ventilating pipes, and the smoke issued in dense masses from each of them, but did not escape anywhere into the house, showing that the pipes were sound. if the engineer wishes to increase the severity of the test, he throws a wet cloth over the top of the ventilating pipe, and so gets a slight pressure of smoke inside it. * * * * * the gas engine.[ ] [footnote : lecture by mr. dugald clerk, before the literary and philosophical society, oldham.] by dugald clerk. in earlier days of mechanics, before the work of the great scottish engineer, james watt, the crude steam engines of the time were known as "fire engines," not in the sense in which we now apply the term to machines for the extinguishing of fires, but as indicating the source from which the power was derived, motive power engines deriving their vitality and strength from fire. the modern name--steam engine--to some extent is a misleading one, distracting the mind from the source of power to the medium which conveys the power. similarly the name "gas engine" masks the fact of the motors so called being really fire or heat engines. the gas engine is more emphatically a "fire engine" than ever the steam engine has been. in it the fire is not tamed or diluted by indirect contact with water, but it is used direct; the fire, instead of being kept to the boiler room, is introduced direct into the motor cylinder of the engine. this at first sight looks very absurd and impracticable; difficulties at once become apparent of so overwhelming a nature that the problem seems almost an impossible one; yet this is what has been successfully accomplished in the gas engine. engineers accustomed to the construction of steam engines would not many years ago have considered any one proposing such a thing as having taken leave of his senses. the late sir william siemens worked for many years on combustion engines, some of his patents on this subject dating back to . in the course of a conversation i had with him on the subject of his earlier patents, i asked him why he had entitled one of those patents "steam engine improvements" when it was wholly concerned with a gas engine using hydrogen and air in the motive cylinder, the combustion of the hydrogen taking place in the motive cylinder. he answered me that in he did not care to entitle his patent gas or combustion engine simply because engineers at that time would have thought him mad. notwithstanding this widespread incredulity among engineers, and the apparent novelty of the gas engine idea, fire or combustion engines have been proposed long, long ago. the first newcomen steam engine ever set to work was used by a mr. back, of wolverhampton, in the year . thirty-one years before this time, in paris--year --huyghens presented a memoir to the academy of sciences describing a method of utilizing the expansive force of gunpowder. this engineer is notable as being the very first to propose the use of a cylinder and piston, as well as the first combustion engine of a practical kind. the engine consists of a vertical open topped cylinder, in which works a piston; the piston is connected by a chain passing over a pulley above it to a heavy weight; the upstroke is accomplished by the descent of the weight, which pulls the piston to the top of the cylinder; gunpowder placed in a tray at the bottom of the cylinder is now ignited, and expels the air with which the cylinder is filled through a shifting valve, and, after the products of combustion have cooled, a partial vacuum takes place and the atmospheric pressure forces down the piston to the bottom of its stroke, during which work may be obtained. on the board i have made a sketch of this engine. some years previous to huyghens' proposal, the abbe hautefeuille ( ) proposed a gunpowder engine without piston for pumping water. it is similar to savery's steam engine, but using the pressure of the explosion instead of the pressure of steam. this engine, however, had no piston, and was only applicable as a pump. the savery principle still survives in the action of the well-known pulsometer steam pump. denys papin, the pupil and assistant of huyghens, continued experimenting upon the production of motive power, and in published a description of his attempts at leipzig, entitled "a new method of securing cheaply motive power of considerable magnitude." he mentions the gunpowder engine, and states that "until now all experiments have been unsuccessful; and after the combustion of the exploded powder there always remains in the cylinder one-fifth of its volume of air." for the explosion of the gunpowder he substituted the generation and condensation of steam, heating the bottom of his cylinder by a fire; a small quantity of water contained in it was vaporized, and then on removing the fire the steam condensed and the piston was forced down. this was substantially the newcomen steam engine, but without the separate boiler. papin died about the year , a disappointed man, about the same time as newcomen. thomas newcomen, ironmonger and blacksmith, of dartmouth, england, had first succeeded in getting his engine to work. the hard fight to wrest from nature a manageable motive power and to harness fire for industrial use was continued by this clever blacksmith, and he succeeded when the more profound but less constructively skillful philosophers had failed. the success of the steam method and the fight necessary to perfect it to the utmost absorbed the energy of most able engineers--beighton, john smeaton--accomplishing much in applying and perfecting it before the appearance of james watt upon the scene. it is interesting to note that in england alone over , horse power of newcomen engines were at work before watt commenced his series of magnificent inventions; he commenced experimenting on a newcomen engine model in at glasgow university, and in came to birmingham, entered into partnership with boulton, and we find his beautiful double acting beam condensing engine in successful work. from that time until now the steam engine has steadily advanced, increasing in economy of fuel from lb. of coal per horse power per hour to about ¾ lb. per horse power per hour, which is the best result of to-day's steam engine practice. this result, according to the highest authorities, is so near to the theoretical result possible from a steam engine that further improvement cannot now be looked for. simultaneously with the development of the steam engine, inventors continued to struggle with the direct acting combustion or gas engine, often without any definite understanding of why they should attempt such apparent impossibilities, but always by their experiments and repeated failures increasing knowledge, and forming a firm road upon which those following them traveled to success. in john barber obtained a patent for an engine producing inflammable gas, mixing it with air, igniting it, and allowing the current so produced to impinge upon a reaction wheel, producing motion similar to the well known aelopile, which i have at work upon the table. about this time, murdoch (jas. watt's assistant at birmingham) was busy introducing coal gas into use for lighting; in boulton and watt's works were lighted up with coal gas. from this time many gas engines were proposed, and the more impracticable combustion of gunpowder received less attention. in thomas mead obtained a patent for an engine using the internal combustion of gas; the description is not a clear one, his ideas seem confused. in the same year robert street obtained a patent for an engine which is not unlike some now in use. the bottom of a cylinder, containing a piston, is heated by a fire, a few drops of spirits of turpentine are introduced and evaporated by the heat, the piston is drawn up, and air entering mixes with the inflammable vapor. a light is applied at a touch hole, and the explosion drives up the piston, which, working on a lever, forces down the piston of a pump for pumping water. robt. street adds to his description a note: "the quantity of spirits of tar or turpentine to be made use of is always proportional to the confined space, in general about drops to a cubic foot." this engine is quite a workable one, although the arrangements described are very crude. the first gas engine that was actually at work for some years; and was applied to a variety of purposes, was samuel buren's. his patent was granted in , and in he built a locomotive carriage with which he made several experimental runs in london; he also propelled a vessel with it upon the thames, and fitted up a large engine for pumping purposes. a company was formed to introduce his engine, but it proved too wasteful of fuel, and the company went into voluntary liquidation. like almost all engines of this time, the combustion of gas and air was used to produce a vacuum, the piston being driven by atmospheric pressure. buren's locomotive carriage was thus in action three years before the great trial in , from which george stephenson emerged victorious with his wonderful engine "the rocket." to those curious in the matter, i may mention that s. buren's patents are dated , no. , , and , no. , . from this time on, a continuous series of gas engine patents appear, engines being patented between and , which is the next date worthy of particular mention. in this year, , the famous "lenoir" engine appeared. the use of high pressure steam engines had long been common, and lenoir's engine was analogous to the high pressure engine, as buren's was to the condensing engine. it created a very general interest, and many engines were constructed and used in france, england, and america; it resembled very much in external appearance an ordinary high pressure horizontal steam engine, and it was double acting. during the following six years, other british patents were granted, and the gas engine passed from the state of a troublesome toy to a practicable and widely useful machine. from to the end of , in all british patents were granted for gas engines, and in these patents are to be found the principles upon which the gas engines of to-day are constructed, many years elapsing before experience enough was gained to turn the proposals of the older inventors to practical account. the most important of these patents are: no. year. robert street , direct-acting engine. samuel buren , vacuum engine. samuel buren , vacuum engine. w.l. wright , direct-acting engine. wm. barnett , compression first proposed. barsante & matteucci , rack & clutch engine. drake direct-acting engine. lenoir d.i. engine, electric ignition. c.w. siemens , compression, _constant pressure_. hugon , platinum ignition. millein , compression, both constant vol. and _pressure_. f.h. wenham , free piston. hugon flame ignition. otto and langen rack and clutch, flame ignition. leaving for the present the history of the gas engine, which brings us to a stage comparable to the state of the steam engine during the newcomen's time, it will be advisable to give some consideration to the principles concerned in the economical and efficient working of gas engines, in order to understand the more recent developments. it has been seen that gunpowder was the explosive used to produce a vacuum in huyghens' engine, and that it was abandoned in favor of gas by buren in . the reason of departure is very obvious: a gunpowder explosion and a gaseous explosion differ in very important practical points. gunpowder being a solid substance is capable of being packed into a very small space; the gas evolved by its decomposition is so great in volume that, even in the absence of any evolution of heat, a very high pressure would result. one cubic inch of gunpowder confined in a space of one cubic inch would cause a pressure by the gas it contains alone of , lb. per square inch; if the heating effect be allowed for, pressures of four times that amount, or , lb. per square inch, are easily accounted for. these pressures are far too high for use in any engine, and the bare possibility of getting such pressure by accident put gunpowder quite outside the purpose of the engineer, quite apart from any question of comparative cost. in a proper mixture of inflammable gas and air is found an exceedingly safe explosive, perfectly manageable and quite incapable of producing pressures in any sense dangerous to a properly constructed engine. the pressure produced by the explosion of any mixture of gas and air is strictly determined and limited, whereas the pressure produced by the explosion of gunpowder depends greatly upon the relation between the volume of the gunpowder and the space in which it is confined. engines of the "lenoir" type are the simplest in idea and construction; in them a mixture of gas and air is made in the cylinder during the first half of the piston stroke, air being taken from the atmosphere and drawn into the cylinder by the forward movement of the piston. at the same time gas entering by a number of holes, and streaming into the air to form an explosive mixture, the movement of a valve cuts off the supply, and brings the igniting arrangement into action. the pressure produced by the explosion acting upon the piston makes it complete its stroke, when the exhaust valve opens exactly as in the steam engine. the lenoir and hugon engines, the earlier forms of this type, were double acting, receiving two impulses for every revolution of the crank, the impulse differing from that in a high pressure steam engine in commencing at half stroke. the lenoir igniting arrangement was complicated and troublesome. i have it upon the table; the mixture was ignited at the proper time by the electric spark produced from a primary battery and ruhmkorff coil. the hugon engine was an advance in this respect, using a flame ignited, and securing greater certainty of action in a comparatively simple manner. it is really a modification of barnett's lighting cock described in his patent of . other difficulties were found in using these engines; the pistons became exceedingly hot. in the case of the lenoir larger engines, it sometimes became red hot, and caused complete ruin of the cylinder by scoring and cutting up. hugon to prevent this injected some water. in the all important question of economy, these engines were found grievously wanting, lenoir consuming cubic feet per i.h.p. per hour; hugon consuming cubic feet per i.h.p. per hour. the surviving engines of this type are only used for very small powers, from one to four man power, or / to / horse, the most widely known of this kind being the "bischoff," which is very largely used; its consumption of gas is even greater than the lenoir, being cubic feet per horse power per hour, as tested with a half-horse engine at a late exhibition of gas apparatus at stockport. so large a consumption of gas prevented these engines coming into extended use for engines of moderate power, and led inventors to work to obtain better results. the force generated by the explosion of a mixture of gas and air is very short lived, and if it is to be fully utilized must be used quickly; a high pressure is produced, but it very quickly disappears. the quicker the piston moves after the maximum pressure is reached, the less will be the loss of heat to the sides of the cylinder. the flame which fills the cylinder and causes the increase of pressure rapidly loses heat, and the pressure falls. the idea of using a free piston was proposed as a remedy; it was thought that a piston connected to a crank in the ordinary manner could not move fast enough to utilize the pressure before it was lost. many inventors proposed to perform work upon a piston free from any direct connection with the crank or shaft of the engine; the explosion after attaining its maximum pressure expends its force in giving velocity to a piston; the velocity so acquired carries it on against atmospheric pressure until the energy is all absorbed, and a vacuum or deficit of pressure exists in the cylinder instead of an excess of pressure. the return stroke is accomplished by the atmospheric pressure, and the work is now done upon the engine shaft on the return only. the method of connecting on the return stroke while leaving the piston free on the out stroke varies, but in many engines the principle was the same. barsante and matteucci, year , british patent no. , , describe the first engine of this kind, but messrs. otto and langen were the first to successfully overcome all difficulties and make a marketable engine of it. their patent was dated , no. . to distinguish it from otto's later patents, it may be called the rack and clutch engine. the economy obtained by this engine was a great advance upon the lenoir. according to a test by prof. tresca, at the paris exhibition of , the gas consumed was cubic feet per indicated horse power per hour. according to tests i have made myself in manchester with a two horse power engine, otto and langen's free piston engine consumes cubic feet per i.h.p. per hour. this is less than one-half of the gas used by the hugon engine for one horse power. the igniting arrangement is a very good modification of barnett's lighting cock, which i have explained already, but a slide valve is used instead of a cock. other engines carried out the same principle in a different manner, including gilles' engine, but they were not commercially so successful as the otto and langen. mr. f.h. wenham's engine was of this type, and was working in england, mr. wenham informed me, in , his patent being taken out in . the great objection to this kind of engine is the irregularity and great noise in working; this was so great as to prevent engines from being made larger than three horse power. the engine, however, did good work, and was largely used from until the end of , when mr. otto produced his famous engine, now known as "the otto silent gas engine." in this engine great economy is attained without the objectionable free piston by a method proposed first by burnett, , and also by a frenchman, millein, in ; this method is compression before ignition. other inventors also described very clearly the advantages to be expected from compression, but none were able to make it commercially successful till mr. otto. to him belongs the great credit of inventing a cycle of operations capable of realizing compression in a simple manner. starting from the same point as inventors did to produce the free piston engine--namely, that the more quickly the explosive force is utilized, the less will be the loss, and the greater the power produced from a quantity of burning gas--it is evident that if any method can be discovered to increase the pressure upon the piston without increasing the temperature of the flame causing this pressure, then a great gain will result, and the engine will convert more of the heat given to it into work. this is exactly what is done by compression before ignition. suppose we take a mixture of gas and air of such proportions as to cause when exploded, or rather ignited (because explosion is too strong a term), a pressure of lb. above atmosphere, or lb. per square inch absolute pressure. then this mixture, if compressed to half volume before igniting and kept at constant temperature, would give, when ignited, a pressure of lb. total, or lb. above atmosphere, and this without any increase of the temperature of the flame. the effect of compression is to make a small piston do the work of a large one, and convert more heat into work by lessening the loss of heat through the walls of the cylinder. in addition to this advantage, greater expansions are made possible, and therefore greatly increase economy. the otto engine must be so familiar in appearance to all of you, that i need hardly trouble you with details of its external appearance. i shall briefly describe its action. its strong points and its weak points are alike caused by its cycle. one cylinder and piston suffices to carry out its whole action. its cycle is: first outstroke, gas and air sucked into the cylinder; first instroke, gas and air compressed into space; second outstroke, impulse due to ignition; second instroke, discharge of exhausted gases. when working at full power, it gets one impulse for every two revolutions; this seems to be a retrograde movement, but, notwithstanding, the advantages obtained are very great. the igniting arrangement is in the main similar to that used on the rack and clutch engine. the engine has been exceedingly successful, and is very economical. the otto compression engine consumes cubic feet of gas per i.h.p. per hour, and runs with great smoothness. in i commenced my work upon gas engines, and very soon concluded that the compression system was the true line to proceed upon. it took me two years to produce a workable engine. my efforts have always been directed toward producing an engine giving at least one impulse every revolution and, if possible, to start without hand labor, just as a steam engine does. my first gas engine was running in , and patented and exhibited in . it was first exhibited at the kilburn royal agricultural society's show. this engine was self-starting, gave an ignition at every revolution, and ignited without external flame. it consisted of two cylinders, a motor, and a compressing pump, with a small intermediate reservoir. suitable valves introduced the mixture of gas and air into the pump, and passed it when compressed from the reservoir to the motor cylinder. the igniting arrangement consisted of a platinum cage firmly fixed in a valve port; this cage was heated in the first instance by a flame of gas and air mixed; it became white hot in a few seconds, and then the engine was started by opening a valve. the platinum was kept hot by the heat derived from the successive ignitions, and, the engine once started, no further external flame was required. i have here one of these platinum cages which has been in use. finding this method not well suited for small engines, i produced the engine which is at present in the market under my name. the cycle is different, and is designed for greater simplicity and the avoidance of back ignitions. it also consists of two cylinders, motor cylinder and the displace or charging cylinder. there is no intermediate reservoir. the displace crank leads the motor by a right angle, and takes into it the mixed charge of gas and air, in some cases taking air alone during the latter part of its stroke. the motor on the outstroke crosses v-shaped parts about from one-sixth to one-seventh from the out end, the displacer charge now passing into the motor cylinder, displacing the exhaust gases by these ports and filling the cylinder and the space at the end of it with the explosive mixture. the introduction of some air in advance of the charge serves the double purpose of cooling down the exhaust gases and preventing direct contact of the inflammable mixture with flame which may linger in the cylinder from the previous stroke. the instroke of the motor compresses the charge into the conical space at the end of the cylinder, and, when fully compressed, ignition is effected by means of the slide i have upon the table. this system of ignition has been found very reliable, and capable of acting as often as times per minute, which the otto ignite is quite incapable of doing. by this cycle the advantages of compression are gained and one step nearer to the steam engine is attained, that is, an impulse is given for every revolution of the engine. as a consequence, i am able with my engine to give a greater amount of power for a comparatively small weight. in addition to this, i have introduced a method of self-starting; in this i believe i was the first--about of my engines are now using self-starting. the largest single engine i have yet made indicates h.p. the consumption of gas in glasgow is: clerk engine consumes in glasgow cubic feet per i.h.p. per hour; clerk engine consumes in manchester cubic feet per i.h.p. per hour. so far as i know, the otto engine and my own are the only compression engines which have as yet made any success in the market. other engines are being continually prepared, gas engine patents being taken out just now at the rate of per annum, but none of them have been able as yet to get beyond the experimental stage. the reason is simply the great experience necessary to produce these machines, which seem so very simple; but to the inexperienced inventor the subject fairly bristles with pitfalls. i have here sections of some of the earlier engines, including dr. siemens' and messrs. simon and beechy. although interesting and containing many good points, these have not been practically successful. the simon engine is an adaptation of the well-known american petroleum motor, the brayton, the only difference consisting in the use of steam as well as flame. dr. siemens worked for some twenty years on gas engines, but he aimed rather high at first to attain even moderate success. had he lived, i doubt not but that he would have succeeded in introducing them for large powers. in he informed me that he had in hand a set of gas engines of some hundreds of horse power for use on board ship, to be supplied with gas from one of his gas producers modified to suit the altered conditions. summarizing the ground over which we have passed, we find the origin of the gas engine in the minds of the same men as were first to propose the steam engine, huyghens and papin, and . greater mechanical difficulties and ignorance of the nature of explosives caused the abandonment of the internal combustion idea, and the mechanical difficulties with steam being less, the steam engine became successful, and triumphed over its rival. the knowledge and skill gained in the construction of steam engines made it possible once again to attack the more difficult problem, and simultaneously with the introduction and perfecting of the steam engine, the gas engine idea became more and more possible, the practicable stage commencing with lenoir and continuing with hugon, millein, otto and langen, f.h. wenham, then otto and clerk. in , cubic feet of gas produced one horse power for an hour; in , cubic feet accomplished the same thing; and now ( ) we can get one horse power for an hour for from to cubic feet of gas, depending on the size of the engine used. considered as a heat engine, the gas engine is now twice as efficient as the very best modern steam engine. it is true the fuel used at present is more expensive than coal, and for large powers the steam engine is the best because of this. but the way is clearing to change this. gas engines as at present, if supplied with producer gas, produced direct from coal without leaving any coke, as is done in the siemens, the wilson, and the dawson producers, will give power at one-half the cost of steam power. they will use / of a pound of coal per horse power per hour, instead of - / lb., as is done in the best steam engines. the only producer that makes gas for gas engines at present is the dawson, and in it anthracite is used, because of the difficulty of getting rid of the tar coming from the siemens and wilson producers, using any ordinary slack. when this difficulty has been overcome, and that it will be overcome there can be no manner of doubt, gas engines will rapidly displace the steam engine, because a gas engine with a gas producer, producing gas from any ordinary coal with the same ease as steam is produced from a boiler, will be much safer, and will use one-half the fuel of the very best steam engines for equal power. the first cost also will not be greater than that of steam. the engine itself will be more expensive than a steam engine of equal power, but the gas producer will be less expensive than the boiler at present. perfect as the gas engine now is, considered as a machine for converting heat into work, the possibility of great development is not yet exhausted. its economy may be increased two or even three fold; in this lies the brilliant future before it. the steam engine is nearly as perfect as it can be made; it approaches very nearly the possibility of its theory. its defect does not lie in its mechanism, but in the very properties of water and steam itself. the loss of heat which takes place in converting liquid water into gaseous steam is so great that by far the greater portion of the heat given out by the fuel passes away either in the condenser or the exhaust of a steam engine; but a small proportion of the heat is converted into work. the very best steam engines convert about per cent. of the heat given them into useful work, the remaining per cent. being wasted, principally in the exhaust of the engine. gas engines now convert per cent. of the heat given to them into work, and very probably will, in a few years more, convert per cent. into useful work. the conclusion, then, is irresistible that, when engineers have gained greater experience with gas engines and gas producers, they will displace steam engines entirely for every use--mills, locomotives, and ships. * * * * * rapid construction of the canadian pacific railway. by e.t. abbott, member of the engineers' club of minnesota. read december , . during the winter of and , the contract was let to messrs. langdon, sheppard & co., of minneapolis, to construct during the working season of the latter year, or prior to january , , miles of railroad on the western extension of the above company; the contract being for the grading, bridging, track-laying, and surfacing, also including the laying of the necessary depot sidings and their grading. the idea that any such amount of road could be built in that country in that time was looked upon by the writer hereof, as well as by railroad men generally, as a huge joke, perpetrated to gull the canadians. at the time the contract was let, the canadian pacific railway was in operation to brandon, the crossing of the assiniboine river, miles west of winnipeg. the track was laid, however, to a point about miles west of this, and the grading done generally in an unfinished state for thirty miles further. this was the condition of things when the contract was entered into to build miles--the east end of the -mile contract being at station , (station being at brandon) and extending west to a few miles beyond the saskatchewan river. the spring of opened in the most unpromising manner for railroad operations, being the wettest ever known in that country. traffic over the st. paul, minneapolis & manitoba railroad, between st. paul and winnipeg, was entirely suspended from april to the th, owing to the floods on the red river at st. vincent and emerson, a serious blow to an early start, as on this single track depended the transportation of all supplies, men, timber, and contractors' plant, together with all track materials (except ties), all of these things having to come from or through st. paul and minneapolis. the writer hereof was appointed a division engineer, and reported at winnipeg the th of april, getting through on the last train before the st. vincent flood. no sooner was the line open from st. paul to winnipeg than the cotillon opened between winnipeg and brandon, with a succession of washouts that defied and defeated all efforts to get trains over, so it was not until the fifth day of may that i left winnipeg to take charge of the second division of miles. by extremely "dizzy" speed i was landed at the end of the track, miles from winnipeg, on the evening of the th ( days). my outfit consisted of three assistant engineers and the necessary paraphernalia for three complete camps, days' provisions (which turned out to be about ), carts and ponies, the latter being extremely poor after a winter's diet on buffalo grass and no grain. on the th day of may i had my division organized and camps in running order. the country was literally under water, dry ground being the exception, and i look upon the feat of getting across the country at all as the engineering triumph of my life. on may a genuine blizzard set in, lasting hours, snowed five inches, and froze the sloughs over with half an inch of ice, a decidedly interesting event to the writer, as he was miles from the nearest wood, therefore lay in his blankets and ate hard tack. i stabled my ponies in the cook tent, and after they had literally eaten of the sod inside the tent, i divided my floor with them. on th day of may i saw the first contractor, who broke ground at station , . on the st of june i was relieved from this division, and ordered to take the next, miles west. on the th day of june ground was broken on this division, at station , , or only about miles west of the east end of the -mile contract. it looked at this time as though they might build miles, but not more. but from this time on very rapid progress was made. on july the track reached station , , making however up to this time but about miles of track-laying, including that laid on the old grade; but large forces were put on to surfacing, and the track already laid was put in excellent condition for getting material to the front. the weather from this until the freezing-up was all that could be desired. work ceased about the st of january, , for the season, and the final estimate for the work was as follows: , , cubic yards earth excavation, , , feet b.m. timber in bridges and the culverts, , lineal feet piling, miles of track-laying. this work was all done in working days, including stormy ones, when little, if anything, could be done, making a daily average of , yards excavation, , feet b.m. timber, feet piling, - / miles track-laying. we never had an accurate force report made of the whole line, but roughly there were employed , men and , teams. the admirable organization of the contractors was something wonderful. the grading work was practically all done by sub-contractors, messrs. langdon, sheppard & co. confining themselves to putting in the supplies and doing the bridge work, surfacing, and track-laying. the grading forces were scattered along about miles ahead of the track and supply stores, established about miles apart, and in no case were sub-contractors expected to haul supplies over miles. if i remember rightly, there were four trains of about forty wagons each, hauling supplies from the end of track to the stores. as can be readily seen, the vital point of the whole work, and the problem to solve, was food for men and horses. , bushels of oats every day and , pounds of provisions, sundays and all, for an entire season, which at the beginning of the work had to come about miles by rail, and then be taken from to miles by teams across a wilderness, is on the face of it considerable of an undertaking, to say nothing about hauling the pile-drivers, piles, and bridge-timber there. to keep from delaying the track, sidings , feet long were graded, about miles apart. a side-track crew, together with an engine, four flats, and caboose, were always in readiness; and as soon as a siding was reached, in five hours the switches would be in, and the next day it would be surfaced and all in working order, when the operating department would fill it with track material and supplies. from the head of the siding to the end of the track the ground was in hands of track-laying engine, never going back of the last siding for supplies or material, and my recollection is that there were but six hours' delay to the track from lack of material the whole season, at any rate up to some time in november. the track-laying crew was equal to miles per day, and in the month of august miles of track were laid. the ties were cut on the line of the road about miles east of winnipeg, so the shortest distance any ties were hauled was miles; the actual daily burden of the single track from winnipeg west was cars steel, cars ties, aside from the transportation of grain and provisions, bridge material, and lumber for station houses. the station buildings were kept right up by the company itself, and a depot built with rooms for the agent every miles, or at every second siding. the importance of keeping the buildings up with the track was impressed on the mind of the superintendent of this branch, and, as a satire, he telegraphed asking permission to haul his stuff ahead of the track by teams, he being on the track-layers' heels with his stations and tanks the whole season. the telegraph line was also built, and kept right up to the end of the track, three or four miles being the furthest they were at any time behind. it might be supposed that work done so rapidly would not be well done, but it is the best built prairie road i know of on this continent. it is built almost entirely free from cuts, and the work is at least per cent. heavier than would ordinarily be made across the same country in the states, on account of snow. , ties were laid to the mile, and the track ballasting kept well up with the laying; so well, in fact, and so well done, that as mile sections were completed schedule trains were put on miles an hour, and the operating department had nothing to do but make a time table; the road was _built_ by the construction department before the operating department was asked to take it. the engineering was organized in divisions of miles each, and as each was finished the parties moved ahead again to the front, the engineers usually finding men sitting on their shovels waiting for the work to be laid out for them. it was as much as the locating parties could do to keep out of the way of the construction. the roadbed was built ft. wide in embankment and in the very few cuts there were, there being no cuts of any moment except through the coteaus and the saskatchewan crossing, and these have since been widened out on account of snow, so that the road can be operated the year round and the bucking-snow account cut no figure in the operating expenses. the country is a virgin desert. from winnipeg to the pacific ocean there are a few places that might attain to the dignity of an _oasis_--at brandon, portage la prairie, etc.--but it is generally what i should call worthless; miles to wood and feet to water was the general experience west of the moose jaw, and the months of june, july, and august are the only three in the year that it is safe to bet you will not have sleighing. i burned wood and used stakes that were hauled by carts miles, and none any nearer. it is a matter of some pride that both the engineering and the construction were done by what our canadian neighbors kindly termed "yankee importations." however, there was one thing that in the building of this road was in marked contrast to any other pacific road ever constructed, that is, there was no lawlessness, no whisky, and not even a knock-down fight that i ever heard of the whole season, and even in the midst of , indians, all armed with winchester rifles and plenty of ammunition, not one of the locating or construction parties ever had a military escort, nor were any depredations ever committed, except the running off of a few horses, which were usually recovered; and i think there were but two fatal accidents during the season, one man killed on the grand coule bridge, and another from being kicked by a horse. the track was all laid from one end, and in no case were rails hauled ahead by teams. two iron cars were used, the empty returning one being turned up beside the track to let the loaded one by. the feat in rapid construction accomplished by this company will never be duplicated, done as it was by a reckless expenditure of money, the orders to the engineers being to _get there_ regardless of expense and horse-flesh; if you killed a horse by hard driving, his harness would fit another, and there was no scrutiny bestowed on vouchers when the work was done; and i must pay the tribute to the company to say that everything that money would buy was sent to make the engineers comfortable. it was bad enough at best, and the chief engineer (j.c. james) rightly considered that any expense bestowed on the engineering part of the work was a good investment. * * * * * the osgood mammoth excavator. in the accompanying illustration, we present to our readers a mammoth excavator, built by the osgood dredge company of albany, n.y., for the pacific guano company of california, for uncovering their phosphate deposits on chisholm island, south colombia. [illustration: the osgood mammoth excavator.] in order to bring out more clearly the principal problem involved in the construction of this machine, we shall state first the proposed method of its operation. this is as follows, viz.: the excavator is to dig a trench thirty feet wide, down to the phosphate rock, and the entire length of the bed--about one quarter of a mile--dumping the earth of the first cut to one side. the phosphate is taken out behind the excavator. on reaching the end of the bed, the excavator is reversed and starts back, making a second cut thirty feet wide, and dumping now into the cut from which the phosphate has just been removed. in this way the entire bed is traversed, the excavator turning over the earth in great furrows thirty feet wide, and giving an opportunity to simultaneously get out all the phosphate. as will be seen, the main problem presented was to turn the car around at each end of the cut in a very limited space. to accomplish this, the car is mounted on a fixed axle at each end and on a truck under its center of gravity; this is somewhat forward of the geometrical center of the car. the frame of the truck is circular, thirteen feet in diameter, made of i beams curved to shape. the circle carries a track, on which a ring of coned rollers revolves, which in turn supports the car. by pulling out the track from under both ends of the car, the whole weight is balanced on this central turntable truck, thus admitting of the car being turned, end for end, within its own length. this method of turning the car, and the size of the machine, are the principal features. the car is ' × ', with arched truss sides. the track is seven feet gauge, the spread between tracks feet, the height of the a frame feet, length of boom feet, swinging in a circle of feet radius, and through two-thirds of the entire circle. it has a steel dipper of cubic feet capacity, inch steel chains, " × " double cylinder hoisting engine, and ¼" × " double cylinder reversible crowding engine. the drums are fitted with friction clutches. owing to the great distance at which the dipper is handled, its size is reduced, and because it swings on the arc of so large a circle the capacity of this machine is only one-half of that of the no. excavator built by the osgood dredge company. nevertheless it will do the work of from to men, since its capacity is from to , cubic yards per day, the amount of rock _uncovered_ depending, of course, upon the depth of earth overlying it. the excavator will dump feet from the center line of the car, and feet above the track, which is laid on the rock. total weight about fifty tons. the crew required for its operation consists of engineer, fireman, craneman, and to pit men to tend jacks, move track, etc. in the illustration the boiler connections are omitted, also the housing for the protection of the crew. the design is characterized by the evident care which has been bestowed upon securing simplicity and durability.--_american engineer._ * * * * * the osgood excavator. at a recent meeting of the engineers' club of philadelphia, mr. john c. trautwine, jr., exhibited and described drawings of a large land dredge built by the osgood dredge co., of albany, new york, for the pacific guano co., to be used in removing to feet of material from the phosphate rock at bull river, s.c. the more prominent features of the machine are the car-body, the water tank, boiler and engine, the a frame (so-called from its slight resemblance to the letter a), the boom, the dipper-handle; and the dipper, drawings of which were shown and described in detail. before the excavation is begun, the forward end of the car (the end nearest the dipper) is lifted clear of the track by means of screw-jacks. when the machine has excavated as far in advance of itself as the length of the boom and that of the dipper-handle will permit, say about feet, the car is again lowered to the track, the screw-jacks removed, and the car is moved forward about feet by winding the rope upon the drum, the other end of the rope being attached to any suitable fixed object near the line of the track. the forward end of the car is then again lifted by means of the screw-jacks, and the digging is resumed. the machine cuts a channel from to feet wide, and deposits all the dirt upon one side. if necessary, it can dump earth about feet above the track. the miners follow in the wake of the machine, getting out the phosphate as fast as it is uncovered. when the machine reaches the end of the field it is lowered to the track and the screw-jacks are removed. shoes or skids are then placed upon the track, and the wheels of the turntable are run up on them. this lifts the end wheels clear of the track, so that the car and machine rest entirely upon the turntable. by now blocking the turntable wheels and winding up only _one_ of the ropes, the car body and the machine are swung around end for end. the digging is then resumed in the opposite direction, the temporary track, upon which the machine travels, being shifted to one side, so that the second channel is made alongside of the first. the earth removed in cutting this second channel is dumped into the first channel, the phosphate (as stated above) having been first removed. the dipper is of plate steel, and holds ¾ cubic yards of earth when even full. the machine is manned by an engineer, a fireman, and a dipper-tender, besides which from five to ten laborers are required. these look after the track, etc. * * * * * capstan navigation on the volga. on several of the large rivers on the continent, with rapid currents, cable towage has been introduced in addition to the older methods of transporting merchandise by sailing and steam boats or by towage with screw or paddle tugs. a chain or wire rope is laid on the bottom of the river bed, fixed to anchors at the ends and passed over a chain pulley driven by the steam engine and guided by pulleys on the steam tug, the tug lifting it out of the water at the bow and dropping it over the stern and winding itself with the barges attached to it along the chain, the latter being utilized as a rule only for the up journey, while down the river the tugs are propelled by paddles or screws, and can tow a sufficient number of barges with the assistance of the current. the system has been found advantageous, as, although the power required for drawing the barges and tugs against the current is of course the same in all cases, the slip and waste of power by screws and paddles is avoided. the size of the screws or paddles is also limited by the nature of the river and its traffic, and with cable towage a larger number of barges can be hauled, while the progress made is definite and there is no drifting back, as occurs with paddle or screw tugs when they have temporarily to slow or stop their engines on account of passing vessels. several streams, as the elbe, rhine, and rhone, have now such cables laid for long distances in those parts of the rivers where the traffic is sufficient to warrant the adoption of the system. while this has been introduced only during the last or years, a similar method of transporting merchandise has been in use in russia on the river volga for upward of years. navigation on this river is interrupted for about half the year by the ice, and the traffic is of larger amount only during part of the summer, while the length of the river itself is very great, so that laying down permanent cables would not pay; while, on the other hand, the current is so strong that towage of some sort must be resorted to for the transport of large quantities. the problem has been solved by the introduction of the capstan navigation or towage. [illustration: capstan navigation on the volga.] there are two kinds of capstans in use, one actuated by horse-power and the other by steam engines. a horse capstan boat carries according to size to horses, which are stabled in the hold. on deck a number of horse gears are arranged at which the horses work. the power of the separate gears is transmitted to a main shaft, which is connected to the drums that wind on the rope. the horses work under an awning to protect them from the burning sunshine, and are changed every three hours. eight and sometimes ten horses work at each horse gear. the horses are changed without interruption of the work, the gears being disengaged from the main shaft in rotation and the horses taken out and put in while the gear is standing. the horses are bought at the place of departure in the south of russia and resold at the destination, usually nishny-novgorod, at a fair profit, the capstan boat carrying fodder and provender for the attendants. the capstan is accompanied by a steam launch which carries the anchor and hawser forward in advance of the capstan. the latter has a diameter of as much as in., and is two to three miles in length. the anchor is dropped by the tug and the hawser carried back to the capstan, where it is attached to one of the rope drums, and the boat with the barges attached to it towed along by the horse gears described above winding on the hawser. the advance continues without interruption day and night, the launch taking a second anchor and hawser forward and dropping the anchor in advance of the first by a hawser's length, so that when the capstan has wound up the first hawser it finds a second one ready for attachment to the rope drum. the launch receives the first hawser, picks up the anchor, and passes the capstan to drop it again in advance of the anchor previously placed, and carries the hawser back to the capstan, and so on. a capstan tows twelve or more barges, placed in twos or threes beside and close behind each other, with a load of a million pounds, or about , to , tons. from astrachan and the mouth of the kama the capstans make during the season from the beginning of may to the end of july in the most favorable case two journeys to the fair of nishny-novgorod; after this time no more journeys are made, as the freights are wanting. at the end of the up-stream journey the horses are sold, as mentioned before, and the capstan towed down stream by the steam launch to astrachan or the kama mouth, where meanwhile a fresh lot of barges has been loaded and got ready, a new supply of horses is bought, and the operation repeated. besides these horse capstans there are steam capstans which are less complicated and have condensing steam engines of about horse power, the power being transmitted by gearing to the rope drum. the rope drum shaft projects on both sides beyond the boards of the boat, and for the return journey paddle wheels, are put on to assist the launch in towing the clumsy and big capstan boat down the river. the steam capstans tow considerably larger masses of goods than the horse capstans and also travel somewhat quicker, so that the launch has scarcely sufficient time to drop and raise the anchors and also to make double the journey. we do not doubt that this system of towage might with suitable modifications be advantageously employed on the large rivers in america and elsewhere for the slow transport of large quantities of raw materials and other bulky merchandise, a low speed being, as is well known, much more economical than a high speed, as many of the resistances increase as the square and even higher powers of the velocity. * * * * * steamboat equipment of war vessels. the larger ships in the navy, and some of the more recent small ones, such as the new cruisers of the phaeton class, are fitted with powerful steam winches of a type made by messrs. belliss and co. these are used for lifting the pinnaces and torpedo boats. we give an illustration of one of these winches. the cylinders are in. in diameter and in. stroke. the barrel is grooved for wire rope, and is safe to raise the second class steel torpedo boats, weighing nearly tons as lifted. the worm gearing is very carefully cut, so that the work can be done quietly and safely. with machinery of this kind a boat is soon put into the water, and as an arrangement is fitted for filling the boat's boilers with hot water from the ship's boilers, the small craft can be under way in a very short time from the order being given. mr. white is fitting compound engines with outside condensers to boats as small as ft. long, and we give a view of a pair of compound engines of a new design, which messrs. belliss are making for the boats of this class. the cylinders are in. and in. in diameter by in. stroke. the general arrangement is well shown in the engraving. on a trial recently made, a ft. cutter with this type of engines reached a speed of . knots. about three years ago the late controller of the navy, admiral sir w. houston stewart, wished to ascertain the relative consumption of fuel in various classes of small vessels. an order was accordingly sent to portsmouth, and a series of trials were made. from the official reports of these we extract the information contained in tables f and g, and we think the details cannot fail to be of interest to our readers. the run around the island was made in company with other boats, without stopping, and observations were taken every half hour. the power given out by the engines was fairly constant throughout. the distance covered was knots, and the total amount of fuel consumed, including that required for raising steam, was , lb. of coal and lb. of wood. the time taken in raising steam to lb. pressure was forty-three minutes. the rate of consumption of fuel is of course not the lowest that could be obtained, as a speed of over knots is higher than that at which the machinery could be worked most economically. [illustration: steam winch for hoisting and lowering pinnacles and torpedo boats.] the trials afterward made to find the best results that could be obtained in fuel consumption were rather spoiled by the roughness of the weather on the day they were made. the same boat was run for miles around the measured mile buoys in stokes bay. the following are some of the results recorded: _table f.--report of trials of engines of h.m. ft. twin screw steam pinnace, no. ._ date august , . where tried round the isle of wight draught of water / forward ft. ½ in. \ aft ft. ½ in. average boiler pressure . lb. average pressure in receivers / starboard . " \ port . " mean air pressure in stokehold . in. water. vacuum in condenser, average . in. weather barometer . " revolutions per minute / starboard . \ port . lb. mean pressure in cylinders / starboard / high . | \ low . \ port / high . \ low . indicated horse-power / starboard / high . | \ low . | port / high . | \ low . \ collective total . speed by log . knots. force of wind one. sea smooth. quantity of coal on board ton. description nixon's navigation. consumption per indicated horse-power per hour . lb. time under way hrs. min. _table g.--report of trial of engines of h.m. ft. steam pinnace no. ._ when tried august , . where tried stokes bay. draught / forward ft. in. \ aft ft. ¼ in. average boiler pressure . lb. vacuum . in. weather barometer . " revolutions per minute / starboard . \ port . indicated horse-power[ ] / starboard / high . | \ low . | port / high . | \ low . \ collective total . speed of vessel by log (approximate) . wind / force to \ direction bow and quarter. state of sea rough. [footnote : in consequence of the seas breaking over the boat, a large number of diagrams were destroyed, and, on account of the roughness of the weather, cards were only taken with the greatest difficulty. the records of power developed are therefore not put forward as authoritative.] in connection with this subject it may perhaps be of interest to give particulars of a french and american steam launch; these we extract from the united states official report before mentioned. _steam launch of the french steamer mouche_. length on low water level ft. - / in. breadth ft. in. depth to rabbet of keel ft. - / in. draught of water aft ft. - / in. weight of hull and fittings , lb. weight of machinery with water in boiler , lb. the boat is built of wood, and coppered. the engine consists of one non-condensing cylinder, - / in. in diameter and . in. stroke. the boiler has . square feet of grate surface. the screw is - / in. in diameter by . in, pitch. the speed is knots per hour obtained with revolutions per minute, the slip being . per cent. of the speed. the united states navy steam cutters built at the philadelphia navy yard are of the following dimensions: length ft. ½ in. breadth ft. in. depth to rabbet of keel ft. ¾ in. displacement (to two feet above rabbet of keel) . tons. weight of hull and fittings , lb. " engine , " " boiler , " " water in boiler and tanks , " the engine has a single cylinder in. in diameter and in. stroke of piston. the screw is four bladed, in. long and in. in diameter by in. pitch. the following is the performance at draught of water feet above rabbet of keel: boiler pressure lb. revolutions speed . knots. indicated horse power. these boats are of type, but may be taken as typical of a large number of steam cutters in the united states navy. the naval authorities have, however, been lately engaged in extensive experiments with compound condensing engines in small boats, and the results have proved so conclusively the advantages of the latter system that it will doubtless be largely adopted in future.--_engineer._ * * * * * improved steam trap. the illustrations we give represent an expansion trap by mr. hyde, and made by mr. s. farron, ashton-under-lyne. the general appearance of this arrangement is as in fig. or fig. , the center view, fig. , showing what is the cardinal feature of the trap, viz., that it contains a collector for silt, sand, or sediment which is not, as in most other traps, carried out through the valve with the efflux of water. the escape valve also is made very large, so that while the trap may be made short, or, in other words, the expansion pipe may not be long, a tolerably large area of outlet is obtained with the short lift due to the small movement of the expansion pipe. [illustration: improved steam trap.] the object of a steam trap is for the removal of water of condensation without allowing the escape of steam from drying apparatus and steam pipes used for heating, power, or other purposes. one of the plans employed is by an expansion pipe having a valve fixed to its end, so that when the pipe shortens from being cooler, due to the presence of the water, the valve opens and allows the escape of the water until the steam comes to the trap, which, being hotter, lengthens the pipe and closes the valve. now with this kind of trap, and, in fact, with any variety of trap, we understand that it has been frequently the experience of the user to find his contrivance inoperative because the silt or sand that may be present in the pipes has been carried to the valve and lodged there by the water, causing it to stick, and with expansion traps not to close properly or to work abnormally some way or other. the putting of these contrivances to rights involves a certain amount of trouble, which is completely obviated by the arrangement shown in the annexed engravings, which is certainly a simple, strong, and substantial article. the foot of the trap is made of cast iron, the seat of the valve being of gun metal, let into the diaphragm, cast inside the hollow cylinder. the valve, d, is also of gun metal, and passing to outside through a stuffing box is connected to the central expansion pipe by a nut at e. the valve is set by two brass nuts at the top, so as to be just tight when steam hot; if, then, from the presence of water the trap is cooled, the pipe contracts and the water escapes. a mud door is provided, by which the mud can be removed as required. the silt or dirt that may be in the pipes is carried to the trap by the water, and is deposited in the cavity, as shown, the water rises, and when the valve, d, opens escapes at the pipe, f, and may be allowed to run to waste. a pipe is not shown attached to f, but needless to say one may be connected and led anywhere, provided the steam pressure is sufficient. for this purpose the stuffing-box is provided; it is really not required if the water runs to waste, as is represented in the engraving. to give our readers some idea of the dimensions of the valve, we may say that the smallest size of trap has in. expansion pipe and a valve in. diameter, the next size ¼ in. expansion pipe and a valve ½ in. diameter, and the largest size has a pipe ½ in. and a valve in. diameter. altogether, the contrivance has some important practical advantages to recommend it.--_mech. world._ * * * * * critical methods of detecting errors in plane surfaces.[ ] [footnote : a paper read before the engineers' society of western pennsylvania, dec. , .] by john a. brashear. in our study of the exact methods of measurement in use to-day, in the various branches of scientific investigation, we should not forget that it has been a plant of very slow growth, and it is interesting indeed to glance along the pathway of the past to see how step by step our micron of to-day has been evolved from the cubit, the hand's breadth, the span, and, if you please, the barleycorn of our schoolboy days. it would also be a pleasant task to investigate the properties of the gnomon of the chinese, egyptians, and peruvians, the scarphie of eratosthenes, the astrolabe of hipparchus, the parallactic rules of ptolemy, regimontanus purbach, and walther, the sextants and quadrants of tycho brahe, and the modifications of these various instruments, the invention and use of which, from century to century, bringing us at last to the telescopic age, or the days of lippershay, jannsen, and galileo. [illustration: fig. .] it would also be a most pleasant task to follow the evolution of our subject in the new era of investigation ushered in by the invention of that marvelous instrument, the telescope, followed closely by the work of kepler, scheiner, cassini, huyghens, newton, digges, nonius, vernier, hall, dollond, herschel, short, bird, ramsden, troughton, smeaton, fraunhofer, and a host of others, each of whom has contributed a noble share in the elimination of sources of error, until to-day we are satisfied only with units of measurement of the most exact and refined nature. although it would be pleasant to review the work of these past masters, it is beyond the scope of the present paper, and even now i can only hope to call your attention to one phase of this important subject. for a number of years i have been practically interested in the subject of the production of plane and curved surfaces particularly for optical purposes, _i.e._, in the production of such surfaces free if possible from all traces of error, and it will be pleasant to me if i shall be able to add to the interest of this association by giving you some of my own practical experience; and may i trust that it will be an incentive to all engaged in kindred work _to do that work well?_ [illustration: fig. .] in the production of a perfectly plane surface, there are many difficulties to contend with, and it will not be possible in the limits of this paper to discuss the methods of eliminating errors when found; but i must content myself with giving a description of various methods of detecting existing errors in the surfaces that are being worked, whether, for instance, it be an error of concavity, convexity, periodic or local error. [illustration: fig. ] a very excellent method was devised by the celebrated rosse, which is frequently used at the present time; and those eminent workers, the clarks of cambridge, use a modification of the rosse method which in their hands is productive of the very highest results. the device is very simple, consisting of a telescope (_a_, fig. ) in which aberrations have been well corrected, so that the focal plane of the objective is as sharp as possible. this telescope is first directed to a distant object, preferably a celestial one, and focused for parallel rays. the surface, _b_, to be tested is now placed so that the reflected image of the same object, whatever it may be, can be observed by the same telescope. it is evident that if the surface be a true plane, its action upon the beam of light that comes from the object will be simply to change its direction, but not disturb or change it any other way, hence the reflected image of the object should be seen by the telescope, _a_, without in any way changing the original focus. if, however, the supposed plane surface proves to be _convex_, the image will not be sharply defined in the telescope until the eyepiece is moved _away_ from the object glass; while if the converse is the case, and the supposed plane is concave, the eyepiece must now be moved _toward_ the objective in order to obtain a sharp image, and the amount of convexity or concavity may be known by the change in the focal plane. if the surface has periodic or irregular errors, no sharp image can be obtained, no matter how much the eyepiece may be moved in or out. [illustration: fig. ] this test may be made still more delicate by using the observing telescope, _a_, at as low an angle as possible, thereby bringing out with still greater effect any error that may exist in the surface under examination, and is the plan generally used by alvan clark & sons. another and very excellent method is that illustrated in fig. , in which a second telescope, _b_, is introduced. in place of the eyepiece of this second telescope, a diaphragm is introduced in which a number of small holes are drilled, as in fig. , _x_, or a slit is cut similar to the slit used in a spectroscope as shown at _y_, same figure. the telescope, _a_, is now focused very accurately on a celestial or other very distant object, and the focus marked. the object glass of the telescope, _b_, is now placed against and "square" with the object glass of telescope _a_, and on looking through telescope a an image of the diaphragm with its holes or the slit is seen. this diaphragm must now be moved until a sharp image is seen in telescope _a_. the two telescopes are now mounted as in fig. , and the plate to be tested placed in front of the two telescopes as at _c_. it is evident, as in the former case, that if the surface is a true plane, the reflected image of the holes or slit thrown upon it by the telescope, _b_, will be seen sharply defined in the telescope, _a_. [illustration: fig. .] if any error of convexity exists in the plate, the focal plane is disturbed, and the eyepiece must be moved _out_. if the plate is concave, it must be moved _in_ to obtain a sharp image. irregular errors in the plate or surface will produce a blurred or indistinct image, and, as in the first instance, no amount of focusing will help matters. these methods are both good, but are not satisfactory in the highest degree, and two or three important factors bar the way to the very best results. one is that the aberrations of the telescopes must be perfectly corrected, a very difficult matter of itself, and requiring the highest skill of the optician. another, the fact that the human eye will accommodate itself to small distances when setting the focus of the observing telescope. i have frequently made experiments to find out how much this accommodation was in my own case, and found it to amount to as much as / of an inch. this is no doubt partly the fault of the telescopes themselves, but unless the eye is rigorously educated in this work, it is apt to accommodate itself to a small amount, and will invariably do so if there is a preconceived notion or bias _in the direction of the accommodation_. [illustration: fig. .] talking with prof. c.a. young a few months since on this subject, he remarked that he noticed that the eye grew more exact in its demands as it grew older, in regard to the focal point. a third and very serious objection to the second method is caused by diffraction from the edges of the holes or the slit. let me explain this briefly. when light falls upon a slit, such as we have here, it is turned out of its course; as the slit has two edges, and the light that falls on either side is deflected both right and left, the rays that cross from the right side of the slit toward the left, and from the left side of the slit toward the right, produce interference of the wave lengths, and when perfect interference occurs, dark lines are seen. you can have a very pretty illustration of this by cutting a fine slit in a card and holding it several inches from the eye, when the dark lines caused by a total extinction of the light by interference may be seen. [illustration: fig. .] if now you look toward the edge of a gas or lamp flame; you will see a series of colored bands, that bring out the phenomenon of partial interference. this experiment shows the difficulty in obtaining a perfect focus of the holes or the slit in the diaphragm, as the interference fringes are always more or less annoying. notwithstanding these defects of the two systems i have mentioned, in the hands of the practical workman they are productive of very good results, and very many excellent surfaces have been made by their use, and we are not justified in ignoring them, because they are the stepping stones to lead us on to better ones. in my early work dr. draper suggested a very excellent plan for testing a flat surface, which i briefly describe. it is a well known truth that, if an artificial star is placed in the exact center of curvature of a truly spherical mirror, and an eyepiece be used to examine the image close beside the source of light, the star will be sharply defined, and will bear very high magnification. if the eyepiece is now drawn toward the observer, the star disk begins to expand; and if the mirror be a truly spherical one, the expanded disk will be equally illuminated, except the outer edge, which usually shows two or more light and dark rings, due to diffraction, as already explained. [illustration: fig. .] now if we push the eyepiece toward the mirror the same distance on the opposite side of the true focal plane, precisely the same appearance will be noted in the expanded star disk. if we now place our plane surface any where in the path of the rays from the great mirror, we should have identically the same phenomena repeated. of course it is presumed, and is necessary, that the plane mirror shall be much less in area than the spherical mirror, else the beam of light from the artificial star will be shut off, yet i may here say that any one part of a truly spherical mirror will act just as well as the whole surface, there being of course a loss of light according to the area of the mirror shut off. this principle is illustrated in fig. , where _a_ is the spherical mirror, _b_ the source of light, _c_ the eyepiece as used when the plane is not interposed, _d_ the plane introduced into the path at an angle of ° to the central beam, and _e_ the position of eyepiece when used the with the plane. when the plane is not in the way, the converging beam goes back to the eyepiece, _c_. when the plane, _d_, is introduced, the beam is turned at a right angle, and if it is a perfect surface, not only does the focal plane remain exactly of the same length, but the expanded star disks, are similar on either side of the focal plane. [illustration: fig. .] i might go on to elaborate this method, to show how it may be made still more exact, but as it will come under the discussion of spherical surfaces, i will leave it for the present. unfortunately for this process, it demands a large truly spherical surface, which is just as difficult of attainment as any form of regular surface. we come now to an instrument that does not depend upon optical means for detecting errors of surface, namely, the spherometer, which as the name would indicate means sphere measure, but it is about as well adapted for plane as it is for spherical work, and prof. harkness has been, using one for some time past in determining the errors of the plane mirrors used in the transit of venus photographic instruments. at the meeting of the american association of science in philadelphia, there was quite a discussion as to the relative merits of the spherometer test and another form which i shall presently mention, prof. harkness claiming that he could, by the use of the spherometer, detect errors bordering closely on one five-hundred-thousandth of an inch. some physicists express doubt on this, but prof. harkness has no doubt worked with very sensitive instruments, and over very small areas at one time. i have not had occasion to use this instrument in my own work, as a more simple, delicate, and efficient method was at my command, but for one measurement of convex surfaces i know of nothing that can take its place. i will briefly describe the method of using it. [illustration: fig. .] the usual form of the instrument is shown in fig. ; _a_ is a steel screw working in the nut of the stout tripod frame, _b_; _c c c_ are three legs with carefully prepared points; _d_ is a divided standard to read the whole number of revolutions of the screw, _a_, the edge of which also serves the purpose of a pointer to read off the division on the top of the milled head, _e_. still further refinement may be had by placing a vernier here. to measure a plane or curved surface with this instrument, a perfect plane or perfect spherical surface of known radius must be used to determine the zero point of the division. taking for granted that we have this standard plate, the spherometer is placed upon it, and the readings of the divided head and indicator, _d_, noted when the point of the screw, _a_, just touches the surface, _f_. herein, however, lies the great difficulty in using this instrument, _i.e._, to know the exact instant of contact of the point of screw, _a_, on the surface, _f_. many devices have been added to the spherometer to make it as sensitive as possible, such as the contact level, the electric contact, and the compound lever contact. the latter is probably the best, and is made essentially as in fig. . [illustration: fig. .] i am indebted for this plan to dr. alfred mayer. as in the previous figure, _a_ is the screw; this screw is bored out, and a central steel pin turned to fit resting on a shoulder at _c_. the end of _d_ projects below the screw, _a_, and the end, _e_, projects above the milled head, and the knife edge or pivot point rests against the lever, _f_, which in turn rests against the long lever, _g_, the point, _h_, of which moves along the division at _j_. it is evident that if the point of the pin just touches the plate, no movement of the index lever, _g_, will be seen; but if any pressure be applied, the lever will move through a multiplied arc, owing to the short fulcri of the two levers. notwithstanding all these precautions, we must also take into account the flexure of the material, the elasticity of the points of contact, and other idiosyncrasies, and you can readily see that practice alone in an instrument so delicate will bring about the very best results. dr. alfred mayer's method of getting over the great difficulty of knowing when all four points are in contact is quite simple. the standard plate is set on the box, _g_, fig. , which acts as a resonater. the screw, _a_, is brought down until it touches the plate. when the pressure of the screw is enough to lift off either or all of the legs, and the plate is gently tapped with the finger, a _rattle_ is heard, which is the tell-tale of imperfect contact of all the points. the screw is now reversed gently and slowly until the _moment_ the rattle ceases, and then the reading is taken. here the sense of hearing is brought into play. this is also the case when the electric contact is used. this is so arranged that the instant of touching of the point of screw, _a_, completes the electric circuit, in which an electromagnet of short thick wire is placed. at the moment of contact, or perhaps a little before contact, the bell rings, and the turning of the screw must be instantly stopped. here are several elements that must be remembered. first, it takes time to set the bell ringing, time for the sound to pass to the ear, time for the sensation to be carried to the brain, time for the brain to send word to the hand to cease turning the screw, and, if you please, it takes time for the hand to stop. you may say, of what use are such refinements? i may reply, what use is there in trying to do anything the very best it can be done? if our investigation of nature's profound mysteries can be partially solved with good instrumental means, what is the result if we have better ones placed in our hands, and what, we ask, if the _best_ are given to the physicist? we have only to compare the telescope of galileo, the prism of newton, the pile of volta, and what was done with them, to the marvelous work of the telescope, spectroscope, and dynamo of to-day. but i must proceed. it will be recognized that in working with the spherometer, only the points in actual contact can be measured at one time, for you may see by fig. that the four points, _a a a a_, may all be normal to a true plane, and yet errors of depression, as at _e_, or elevation, as at _b_, exist between them, so that the instrument must be used over every available part of the surface if it is to be tested rigorously. as to how exact this method is i cannot say from actual experience, as in my work i have had recourse to other methods that i shall describe. i have already quoted you the words of prof. harkness. dr. hastings, whose practical as well as theoretical knowledge is of the most critical character, tells me that he considers it quite easy to measure to / of an inch with the ordinary form of instrument. here is a very fine spherometer that dr. hastings works with from time to time, and which he calls his standard spherometer. it is delicately made, its screw being to the inch, or more exactly . inch, or within / of being / of an inch pitch. the principal screw has a point which is itself an independent screw, that was put in to investigate the errors of the main screw, but it was found that the error of this screw was not as much as the . of an inch. the head is divided into two hundred parts, and by estimation can be read to / of an inch. its constants are known, and it may be understood that it would not do to handle it very roughly. i could dwell here longer on this fascinating subject, but must haste. i may add that if this spherometer is placed on a plate of glass and exact contact obtained, and then removed, and the hand held over the plate without touching it, the difference in the temperature of the glass and that of the hand would be sufficient to distort the surface enough to be readily recognized by the spherometer when replaced. any one desiring to investigate this subject further will find it fully discussed in that splendid series of papers by dr. alfred mayer on the minute measurements of modern science published in scientific american supplements, to which i was indebted years ago for most valuable information, as well as to most encouraging words from prof. thurston, whom you all so well and favorably know. i now invite your attention to the method for testing the flat surfaces on which prof. rowland rules the beautiful diffraction gratings now so well known over the scientific world, as also other plane surfaces for heliostats, etc., etc. i am now approaching the border land of what may be called the abstruse in science, in which i humbly acknowledge it would take a vast volume to contain all i don't know; yet i hope to make plain to you this most beautiful and accurate method, and for fear i may forget to give due credit, i will say that i am indebted to dr. hastings for it, with whom it was an original discovery, though he told me he afterward found it had been in use by steinheil, the celebrated optician of munich. the principle was discovered by the immortal newton, and it shows how much can be made of the ordinary phenomena seen in our every-day life when placed in the hands of the investigator. we have all seen the beautiful play of colors on the soap bubble, or when the drop of oil spreads over the surface of the water. place a lens of long curvature on a piece of plane polished glass, and, looking at it obliquely, a black central spot is seen with rings of various width and color surrounding it. if the lens is a true curve, and the glass beneath it a true plane, these rings of color will be perfectly concentric and arranged in regular decreasing intervals. this apparatus is known as newton's color glass, because he not only measured the phenomena, but established the laws of the appearances presented. i will now endeavor to explain the general principle by which this phenomenon is utilized in the testing of plane surfaces. suppose that we place on the lower plate, lenses of constantly increasing curvature until that curvature becomes nil, or in other words a true plane. the rings of color will constantly increase in width as the curvature of the lens increases, until at last one color alone is seen over the whole surface, provided, however, the same angle of observation be maintained, and provided further that the film of air between the glasses is of absolutely the same relative thickness throughout. i say the film of air, for i presume that it would be utterly impossible to exclude particles of dust so that absolute contact could take place. early physicists maintained that absolute molecular contact was impossible, and that the central separation of the glasses in newton's experiment was / , of an inch, but sir wm. thomson has shown that the separation is caused by shreds or particles of dust. however, if this separation is equal throughout, we have the phenomena as described; but if the dust particles are thicker under one side than the other, our phenomena will change to broad parallel bands as in fig. , the broader the bands the nearer the absolute parallelism of the plates. in fig. let _a_ and _b_ represent the two plates we are testing. rays of white light, _c_, falling upon the upper surface of plate _a_, are partially reflected off in the direction of rays _d_, but as these rays do not concern us now, i have not sketched them. part of the light passes on through the upper plate, where it is bent out of its course somewhat, and, falling upon the _lower_ surface of the upper plate, some of this light is again reflected toward the eye at _d_. as some of the light passes through the upper plate, and, passing through the film of air between the plates, falling on the upper surface of the _lower_ one, this in turn is reflected; but as the light that falls on this surface has had to traverse the film of air _twice_, it is retarded by a certain number of half or whole wave-lengths, and the beautiful phenomena of interference take place, some of the colors of white light being obliterated, while others come to the eye. when the position of the eye changes, the color is seen to change. i have not time to dwell further on this part of my subject, which is discussed in most advanced works on physics, and especially well described in dr. eugene lommel's work on "the nature of light." i remarked that if the two surfaces were perfectly _plane_, there would be one color seen, or else colors of the first or second order would arrange themselves in broad parallel bands, but this would also take place in plates of slight curvature, for the requirement is, as i said, a film of air of equal thickness throughout. you can see at once that this condition could be obtained in a perfect convex surface fitting a perfect concave of the same radius. fortunately we have a check to guard against this error. to produce a perfect plane, _three surfaces must_ be worked together, unless we have a true plane to commence with; but to make this true plane by this method we _must_ work three together, and if each one comes up to the demands of this most rigorous test, we may rest assured that we have attained a degree of accuracy almost beyond human conception. let me illustrate. suppose we have plates , , and , fig. . suppose and to be accurately convex and accurately concave, of the same radius. now it is evident that will exactly fit and , and that and will separately fit no. , _but_ when and are placed together, they will only touch in the center, and there is no possible way to make three plates coincide when they are alternately tested upon one another than to make _perfect planes_ out of them. as it is difficult to see the colors well on metal surfaces, a one-colored light is used, such as the sodium flame, which gives to the eye in our test, dark and bright bands instead of colored ones. when these plates are worked and tested upon one another until they all present the same appearance, one may be reserved for a test plate for future use. here is a small test plate made by the celebrated steinheil, and here two made by myself, and i may be pardoned in saying that i was much gratified to find the coincidence so nearly perfect that the limiting error is much less than . of an inch. my assistant, with but a few months' experience, has made quite as accurate plates. it is necessary of course to have a glass plate to test the metal plates, as the upper plate _must_ be transparent. so far we have been dealing with perfect surfaces. let us now see what shall occur in surfaces that are not plane. suppose we now have our perfect test plate, and it is laid on a plate that has a compound error, say depressed at center and edge and high between these points. if this error is regular, the central bands arrange themselves as in fig. . you may now ask, how are we to know what sort of surface we have? a ready solution is at hand. the bands _always travel in the direction of the thickest film of air_, hence on lowering the eye, if the convex edge of the bands travel in the direction of the arrow, we are absolutely certain that that part of the surface being tested is convex, while if, as in the central part of the bands, the concave edges advance, we know that part is hollow or too low. furthermore, any small error will be rigorously detected, with astonishing clearness, and one of the grandest qualities of this test is the absence of "personal equation;" for, given a perfect test plate, _it won't lie_, neither will it exaggerate. i say, won't lie, but i must guard this by saying that the plates must coincide absolutely in temperature, and the touch of the finger, the heat of the hand, or any disturbance whatever will vitiate the results of this lovely process; but more of that at a future time. if our surface is plane to within a short distance of the edge, and is there overcorrected, or convex, the test shows it, as in fig. . if the whole surface is regularly convex, then concentric rings of a breadth determined by the approach to a perfect plane are seen. if concave, a similar phenomenon is exhibited, except in the case of the convex, the broader rings are near the center, while in the concave they are nearer the edge. in lowering the eye while observing the plates, the rings of the convex plate will advance outward, those of the concave inward. it may be asked by the mechanician, can this method be used for testing our surface plates? i answer that i have found the scraped surface of iron bright enough to test by sodium light. my assistant in the machine work scraped three inch plates that were tested by this method and found to be very excellent, though it must be evident that a single cut of the scraper would change the spot over which it passed so much as to entirely change the appearance there, but i found i could use the test to get the general outline of the surface under process of correction. these iron plates, i would say, are simply used for preliminary formation of polishers. i may have something to say on the question of surface plates in the future, as i have made some interesting studies on the subject. i must now bring this paper to a close, although i had intended including some interesting studies of curved surfaces. there is, however, matter enough in that subject of itself, especially when we connect it with the idiosyncrasies of the material we have to deal with, a vital part of the subject that i have not touched upon in the present paper. you may now inquire, how critical is this "color test"? to answer this i fear i shall trench upon forbidden grounds, but i call to my help the words of one of our best american physicists, and i quote from a letter in which he says by combined calculation and experiment i have found the limiting error for white light to be / of an inch, and for na or sodium light about fifty times greater, or less than / of an inch. dr. alfred mayer estimated and demonstrated by actual experiment that the smallest black spot on a white ground visible to the naked eye is about / of an inch at the distance of normal vision, namely, inches, and that a line, which of course has the element of extension, / of an inch in thickness could be seen. in our delicate "color test" we may decrease the diameter of our black spot a thousand times and still its perception is possible by the aid of our monochromatic light, and we may diminish our line ten thousand times, yet find it just perceivable on the border land of our test by white light. do not presume i am so foolish as to even think that the human hand, directed by the human brain, can ever work the material at his command to such a high standard of exactness. no; from the very nature of the material we have to work with, we are forbidden even to hope for such an achievement; and could it be possible that, through some stroke of good fortune, we could attain this high ideal, it would be but for a moment, as from the very nature of our environment it would be but an ignis fatuus. there is, however, to the earnest mind a delight in having a high model of excellence, for as our model is so will our work approximate; and although we may go on approximating _our_ ideal forever, we can never hope to reach that which has been set for us by the great master workman. * * * * * [journal of gas lighting.] photometrical standards. in carrying out a series of photometrical experiments lately, i found that it was a matter of considerable difficulty to keep the flames of the standard candles always at their proper distance from the light to be measured, because the wick was continually changing its position (of course carrying the flame with it), and thus practically lengthening or shortening the scale of the photometer, according as the flame was carried nearer to or farther from the light at the other end of the scale. in order, therefore, to obtain a correct idea of the extent to which this variation of the position of the wick might influence the readings of the photometer scale, i took a continuous number of photographs of the flame of a candle while it was burning in a room quite free from draught; no other person being in it during the experiment except a photographer, who placed sensitive dry plates in a firmly fixed camera, and changed them after an exposure of seconds. in doing this he was careful to keep close to the camera, and disturb the air of the room as little as possible. in front of the candle a plumb-line was suspended, and remained immovable over its center during the whole operation. the candle was allowed to get itself into a normal state of burning, and then the wick was aligned, as shown in the photographs nos. and , after which it was left to itself. [illustration: variation in photometrical standards.] with these photographs (represented in the cuts) i beg to hand you full-sized drawings of the scales of a inch evans and a inch letheby photometer, in order to give your readers an opportunity of estimating for themselves the effect which such variations from the true distance between the standard light and that to be measured, as shown in this series of photographs, must exercise on photometrical observations made by the aid of either of the instruments named. w. sugg. * * * * * bleaching or dyeing-yarns and goods in vacuo. [illustration] many attempts have been made to facilitate the penetration of textile fabrics by the dyeing and bleaching solutions, with which they require to be treated, by carrying out the treatment in vacuo, _i.e._, in such apparatus as shall allow of the air being withdrawn. the apparatus shown in the annexed engraving--austrian pat. jan. , --although not essentially different from those already in use, embodies, the _journal of the society of chemical industry_ says, some important improvements in detail. it consists of a drum a, the sides of which are constructed of stout netting, carried on a vertical axis working through a stuffing-box, which is fitted in the bottom of the outer or containing vessel or keir b. the air can be exhausted from b by means of an air pump. a contains a central division p, also constructed of netting, into which is inserted the extremity of the tube r, after being twice bent at a right angle. p is also in direct connection with the efflux tube e, e and r serving to convey the dye or bleach solutions to and from the reservoir c. the combination of the rotary motion communicated to a, which contains the goods to be dyed or bleached, with the very thorough penetration and circulation of the liquids effected by means of the vacuum established in b, is found to be eminently favorable to the rapidity and evenness of the dye or bleach. * * * * * on the moulding of porcelain. by chas. lauth. the operation of moulding presents numerous advantages over other methods of shaping porcelain, for by this process we avoid irregularities of form, twisting, and visible seams, and can manufacture thin pieces, as well as pieces of large dimensions, of a purity of form that it is impossible to obtain otherwise. the method of moulding small objects has been described with sufficient detail in technical works, but such is not the case with regard to large ones, and for this reason it will be of interest to quote some practical observations from a note that has been sent me by mr. constantine renard, who, for several years, has had the superintendence of the moulding rooms of the sevres works. the process of moulding consists in pouring porcelain paste, thinned with water, into very dry plaster moulds. this mixture gradually hardens against the porous sides with which it is in contact, and, when the thickness of the hardened layer is judged sufficient, the mould is emptied by inverting it. the excess of the liquid paste is thus eliminated, while the thicker parts remain adherent to the plaster. shortly afterward, the absorption of the water continuing, the paste so shrinks in drying as to allow the object to detach itself from the mould. as may be seen, nothing is simpler when it concerns pieces of small dimensions; but the same is not the case when we have to mould a large one. in this case we cannot get rid of the liquid paste by turning the mould upside down, because of the latter's size, and, on another hand, it is necessary to take special precautions against the subsidence of the paste. recourse is therefore had to another method. in the first place, an aperture is formed in the lower part of the mould through which the liquid may flow at the desired moment. afterward, in order to prevent the solidified but still slightly soft paste from settling under its own weight at this moment, it is supported by directing a current of compressed air into the mould, or, through atmospheric pressure, by forming a vacuum in the metallic jacket in which the mould is inclosed. the history and description of these processes have been several times given, and i shall therefore not dwell upon them, but shall at once proceed to make known the new points that mr. renard has communicated to me. the first point to which it is well to direct the manufacturer's attention is the preparation of the plaster moulds. when it concerns an object of large dimensions, of a vase a yard in height, for example, the moulder is obliged to cut the form or core horizontally into three parts, each of which is moulded separately. to this effect, it is placed upon a core frame and surrounded with a cylinder of sheet zinc. the workman pours the plaster into the space between the latter and the core, and, while doing so, must stir the mass very rapidly with a stick, so that at the moment the plaster sets, it shall be as homogeneous as possible. in spite of such precautions, it is impossible to prevent the densest parts of the plaster from depositing first, through the action of gravity. these will naturally precipitate upon the table or upon the slanting sides of the core, and the mould will therefore present great inequalities as regards porosity. since this defect exists in each of the pieces that have been prepared in succession, it will be seen that when they come to be superposed for the moulding of the piece, the mould as a whole will be formed of zones of different porosities, which will absorb water from the paste unequally. farther along we shall see the inconveniences that result from this, and the manner of avoiding them. [illustration: fig. ] the mould, when finished, is dried in a stove. under such circumstances it often happens that there forms upon the surface of the plaster a hard crust which, although it is of no importance as regards the outside of the mould, is prejudicial to the interior because it considerably diminishes its absorbing power. this trouble may be avoided by coating the surfaces that it is necessary to preserve with clear liquid paste; but mr. renard advises that the mould be closed hermetically, so that the interior shall be kept from contact with warm air. in this way it is possible to prevent the plaster from hardening, as a result of too quick a desiccation. i now come to the operation of moulding. in the very first place, it is necessary to examine whether it is well to adopt the arrangement by pressure of air or by vacuum. the form of the objects will determine the choice. a very open piece, like a bowl, must be moulded by vacuum, on account of the difficulty of holding the closing disk in place if it be of very large dimensions. the same is the case with large vases of wood form. on the contrary, an elongated piece tapering from above is more easily moulded by pressure of the air, as are also ovoid vessels to inches in height. in any case it must not be forgotten that the operation by vacuum should be preferred every time the form of the objects is adapted to it, because this process permits of following and directing the drying, while with pressure it is impossible to see anything when once the apparatus is closed. [illustration: fig. .] _moulding by pressure of the air._--the plaster mould having been put in place upon the mould board, and the liquid paste having been long and thoroughly stirred in order to make it homogeneous, and get rid of the air bubbles, we open the cock that puts the paste reservoir in communication with the lower part of the mould, care having been taken beforehand to pour a few pints of water into the bottom of the mould. the paste in ascending pushes this water ahead of it, and this slightly wets the plaster and makes the paste rise regularly. when the mould is entirely filled, the paste is still allowed to flow until it slightly exceeds the upper level, and, spreading out over the entire thickness of the plaster, forms a sort of thick flange. the absorption of the liquid begins almost immediately, and, consequently, the level lowers. a new quantity of paste is introduced, and we continue thus, in regulating its flow so as to keep the mould always full. this operation is prolonged until the layer is judged to be sufficiently thick, this depending upon the dimensions, form, or construction of the vessel. the operation may take from one to five hours. the desired thickness having been obtained, it becomes a question of allowing the paste to descend and at the same time to support the piece by air pressure. the flange spoken of above is quickly cut, and the paste is made to rise again for the last time, in order to form a new flange, but one that this time will be extremely thin; then a perforated disk designed for forming the top joint, and acting as a conduit for the air, is placed upon the mould. this disk is fastened down with a screw press, and when the apparatus is thus arranged the eduction cock is opened, and the air pump maneuvered. if the flange did not exist, the air would enter between the mould and the piece at the first strokes of the piston, and the piece would be inevitably broken. its object, then, is to form a hermetical joint, although it must at the same time present but a slight resistance, since, as soon as the liquid paste has flowed out, the piece begins to shrink, and it is necessary that at the first movement downward it shall be able to disengage itself, since it would otherwise crack. as soon as the piece begins to detach itself from the mould the air enters the apparatus, and the pressure gauge connected with the air pump begins to lower. it is then necessary, without a moment's loss of time, to remove the screw press, the disk, and the upper part of the mould itself, in order to facilitate as much as possible the contraction of the piece. finally, an hour or an hour and a half later, it is necessary to remove the lower part of the mould, this being done in supporting the entire affair by the middle. the piece and what remains of the mould are, in reality, suspended in the air. all these preparations are designed to prevent cracking. _moulding by vacuum._--the operation by vacuum follows the same phases as those just described. it is well, in order to have a very even surface, not to form a vacuum until about three hours after the paste has been made to ascend. without such a precaution the imperfections in the mould will be shown on the surface of the object by undulations that are irremediable. the first flange or vein must be preserved, and it is cut off at the moment the piece is detached. moulding by vacuum, aside from the advantages noted above, permits of giving the pieces a greater thickness than is obtained in the pressure process. according to mr. renard, when it is desired to exceed one inch at the base of the piece (the maximum thickness usually obtained), the operation is as follows: the piece is moulded normally, and it is supported by a vacuum; but, at the moment at which, under ordinary circumstances, it would be detached, the paste is made to ascend a second time, when the first layer (already thick and dry) acts as a sort of supplementary mould, and permits of increasing the thickness by about / of an inch. the piece is held, as at first, by vacuum, and the paste is introduced again until the desired thickness is obtained. whatever be the care taken, accidents are frequent in both processes. they are due, in general, to the irregular contraction of the pieces, caused by a want of homogeneousness in the plaster of the moulds. in fact, as the absorption of the water does not proceed regularly over the entire surface of the piece, zones of dry paste are found in contact with others that are still soft, and hence the formation of folds, and finally the cracking and breaking of the piece. the joints of the moulds are also a cause of frequent loss, on account of the marks that they leave, and that injure the beauty of the form as well as the purity of the profile. mr. renard has devised a remedy for all such inconveniences. he takes unglazed muslin, cuts it into strips, and, before beginning operations, fixes it with a little liquid paste to the interior of the mould. this light fabric in no wise prevents the absorption of the water, and so the operation goes on as usual; but, at the moment of contraction, the piece of porcelain being, so to speak, supported by the muslin, comes put of the mould more easily and with extreme regularity. under such circumstances all trace of the joint disappears, the imperfections in the mould are unattended with danger, and the largest pieces are moulded with entire safety. in a word, we have here a very important improvement in the process of moulding. the use of muslin is to be recommended, not only in the manufacture of vases, but also in the difficult preparation of large porcelain plates. it is likewise advantageous in the moulding of certain pieces of sculpture that are not very delicate, and, finally, it is very useful when we have to do with a damaged mould, which, instead of being repaired with plaster, can be fixed with well ground wet sand covered with a strip of muslin. _drying of the moulded pieces._--when the moulded pieces become of a proper consistency in the mould, they are exposed to the air and then taken to the drying room. but, as with plaster, the surface of the paste dries very quickly, and this inconvenience (which amounts to nothing in pieces that are to be polished) is very great in pieces that carry ornaments in relief, since the finishing of these is much more difficult, the hardened paste works badly, and frequently flakes off. in order to remedy this inconvenience, it suffices to dust the places to be preserved with powdered dry paste.--_revue industrielle._ * * * * * photo-tricycle apparatus. [illustration: a photo-tricycle apparatus.] this consists of a portable folding camera, with screw focusing arrangement, swing back, and an adapter frame placed in the position of the focus screen, allowing the dark slide to be inserted so as to give the horizontal or vertical position to the dry plate when in the camera. to the front and base-board a brass swiveled side bar, made collapsible by means of a center slot, is attached by hinges, and this renders the camera rigid when open or secure when closed. the base-board is supported on a brass plate within which is inserted a ball-and-socket (or universal joint in a new form), permitting the camera to be tilted to any necessary angle, and fixed in such position at will. the whole apparatus is mounted upon a brass telescopic draw-stand, which, by means of clamps, is attached to the steering handle or other convenient part of the tricycle, preferably the form made by messrs. rudge & co., of coventry, represented in the cut.--_photo. news._ * * * * * a photo printing light. [illustration] a printing frame is placed in the carrier, and exposed to the light of a gas burner kept at a fixed distance, behind which is a spherical reflector. the same frame may be used for other purposes.-_photographic news._ * * * * * a new actinometer. a selenium actinometer has been described in the _comptes rendus_ in a communication from m. morize, of rio de janeiro. the instrument is used to measure the actinic power of sunlight when the sun is at various altitudes; but the same principle is applicable to other light sources. the sensitive part of the apparatus consists of a cylinder formed of disks of copper, isolated from each other by as many disks of mica. the latter being of smaller diameter than the copper disks, the annular spaces between the two are filled with selenium, by the simple process of rubbing a stick of this substance over the edges, and afterward gently warming. the selenium then presents a grayish appearance, and is ready for use. connection is made by conductors, on opposite sides, with the odd and even numbers of the disks, which diminishes the resistance of the selenium. the cylinder thus formed is insulated by glass supports in the inside of a vacuum tube, for the purpose of preserving it from the disturbing influence of dark rays. the whole is placed upon a stand, and shielded from reflected light, but fully exposed to that which is to be measured for actinic intensity. if now a constant current of electricity is passed through the apparatus, as indicated by a galvanometer, the variations of the latter will show the effect produced upon the selenium. a scale must be prepared, with the zero point at the greatest possible resistance of the selenium, which corresponds with absolute darkness. the greatest effect of the light would be to annul the resistance of the selenium. consequently, the cylinder must be withdrawn from the circuit to represent this effect; and the maximum deviation of the galvanometer is then to be observed, and marked . by dividing the range of the galvanometer thus obtained into equal parts, the requisite actinometric scale will be established. in practice, the clamond battery is used to supply the constant current required. * * * * * astronomical photography. during the last few years, or rather decades of years, it has become rather a trite saying that to advance far in any branch of physical research a fair proficiency in no inconsiderable number of the sister sciences is an absolute necessity. but if this is true in general, none, i think, will question the assertion that a proficient in any of the physical sciences must be fairly conversant with photography as a science, or at least as an art. if we take for example a science which has of late years made rapid strides both in europe and america, the science of astronomy, we shall not have far to go to find convincing proof that a great portion of the best work that is being done by its votaries is effected by the aid of photography. one eminent astronomer has quite lately gone so far as to declare that we no longer require observers of the heavens, but that their place can be better supplied by the gelatine plate of the photographer; and his words have been echoed by others not less able than himself. "abolish the observer, and substitute the sensitive plate," is a sensational form of expressing the revolution in observational astronomy that is taking place under our eyes; but, although it suggests a vast amount of truth, it might leave upon the mind an exaggerated impression inimical to the best interests of science. the award of the highest distinction in astronomy, the gold medal of the royal astronomical society, two years in succession, to those who have been most successful in celestial photography is no doubtful sign of the great value attached to such work. last year it was mr. common who received the highest testimony of the merit due to his splendid photographs of the nebula of orion; and this year dr. huggins, who has drawn much attention to celestial photography, by his successful attempts to picture the solar corona in full daylight, has received a similar acknowledgment of his labors in photographing the spectra of stars and comets and nebulæ. an adequate idea of the progress astronomy is now making by aid of photography can only be formed by a comprehensive view of all that is being at present attempted; but a rapid glance at some of the work may prepare the way for a more thorough investigation. a few years since, the astronomers who had advanced their science by aid of photography were few in number, and their results are soon enumerated. some good pictures of the solar corona taken during solar eclipses, a series or two of sun-spot photographs, and a very limited number of successful attempts made upon the moon, and planets, and star clusters, were all the fruits of their labors. but now each month we learn of some new and efficient laborer in this field, which gives promise of so rich a harvest. each day the sun is photographed at greenwich, at south kensington, in india, and at the physical observatory of potsdam, and thus a sure record is obtained of all the spots upon its surface, which may serve for the study of the periodicity of its changes, and for their probable connection with the important phenomena of terrestrial magnetism and meteorology. in france the splendid sun-pictures obtained by dr. janssen at the physical observatory of meudon have thrown into the shade all other attempts at a photographic study of the most delicate features of the solar surface. dr. huggins has shown that it is possible to obtain a daily photographic record of the solar prominences, and only lately he has secured results that justified a special expedition to the alps to photograph the sun's corona, and he has now moved the admiralty to grant a subsidy to dr. gill, the government astronomer at the cape, by aid of which mr. woods can carry on the experiments that were so encouraging last summer in switzerland. we may, then, reasonably hope to obtain before long a daily picture of the sun and a photographic record of its prominences, and even of a certain portion of the solar corona; but the precious moments of each solar eclipse will always be invaluable for picturing those wondrous details in the corona that are now shown us by photography, and which can be obtained by photography alone. again, how very much is to be learnt in solar physics from the marvelous photographs of the sun's spectrum exhibited last summer by professor rowland; photographs that show as many as one hundred and fifty lines between h and k, and which he is still laboring to improve! the extension, too, of the visible solar spectrum into the ultra-violet by corun, mascart, and others, adds much to our knowledge of the sun; while the photographs of abney in the ultrared increase our information in a direction less expected and certainly less easy of attainment. both these extensions we find most ably utilized in the recent discussion of the very interesting photographs of the spectra of the prominences and of the corona taken during the total eclipse of may , ; and the photographic results of this eclipse afford ample proof that we can not only obtain pictures of the corona by photography that it would be impossible otherwise to procure, but also that in a few seconds information concerning the nature of the solar atmosphere may be furnished by photography that it would otherwise take centuries to accumulate, even under the most favorable circumstances. the advantages to be gained by accurate photographs of the moon and planets, that will permit great enlargements, are too obvious to call for lengthened notice in such a rapid sketch as the present; for it is principally in the observation of details that the eye cannot grasp with the required delicacy, or with sufficient rapidity, that photography is so essential for rapid and sure progress. like the sketches of a solar eclipse, the drawings that are made of comets, and still more of nebulæ, even by the most accomplished artists, are all, to say the least, open to doubt in their delicate details. and the truth of this is so obvious, that it is the expressed opinion of an able astronomer that a single photograph of the nebula of orion, taken by mr. common, would be of more value to posterity than the collective drawings of this interesting object so carefully made by rosse, bond, secchi, and so many others. another most important branch of astronomy, that is receiving very great attention at present, is the mapping of the starry heavens; and herein photography will perhaps do its best work for the astronomer. the trial star map by the brothers henry, of a portion of the milky way, which they felt unable to observe satisfactorily by the ordinary methods, is so near absolute perfection that it alone proves the immense superiority of the photographic method in the formation of star maps. fortunately this subject, which is as vast as it is fundamental, is being taken up vigorously. the henries are producing a special lens for the work; mr. grubb is constructing a special cassgrain reflector for mr. roberts of maghull; and the admiralty have instructed mr. woods to make this part of his work at the cape observatory, under the able direction of dr. gill. besides star maps, clusters, too, and special portions of the heavens are being photographed by the rev. t.e. espin, of west kirby; and such pictures will be of the greatest value, not only in fixing the position at a given date, but also aiding in the determination of magnitude, color, variability, proper motion, and even of the orbits of double and multiple stars, and the possible discovery of new planets and telescopic comets. such are some of the many branches of astronomy that are receiving the most valuable aid at present from photography; but the very value of the gift that is bestowed should make exaggeration an impossibility. photography can well afford to be generous, but it must first be just, in its estimate of the work that has still to be done in astronomy independently of its aid; and although the older science points with just pride to what is being done for her by her younger sister, still she must not forget that now, as in the future, she must depend largely for her progress, not only on the skill of the photographer and the mathematician, but also on the trained eye and ear and hand of her own indefatigable observers.--_s.j. perry, s.j., f.r.s., in br. jour. of photography._ * * * * * electricity as a preventive of scale in boilers. the mineral sediment that generally sticks to the sides of steam boilers, and the presence of which is fraught with the utmost danger, resulting in many instances in great injury to life and property, besides eating away the substance of the iron plate, was referred to in a paper lately read by m. jeannolle before the paris academy of sciences, in which the author described a new method for keeping boilers clean. this method is as follows: the inside of a steam boiler is placed, by means of piles of a certain power, in reciprocal communication, the current passing at one end through positive, and at the other through negative, wires. in incrusted steam boilers, at a temperature ranging from ° to ° fahr., and a pressure of from to lb. to the square inch, the current thus engendered decomposes the accumulated salts, and precipitates them, from which they may easily be removed, either by means of a special siphon or by means of some other mechanical process. when boilers are free from fur, and where it is intended to keep them free from such, a continuous current may be set up, by means of which the sedimentary salts may be decomposed, and a precipitate produced in a pulverized form, which can be removed with equal facility. from a series of minute experiments made by m. jeannolle, it appears that in order to render the various actions of electricity, perfect, it is necessary to coat either with red lead or with pulverized iron, or with any other conductor of electricity, an operation which must be repeated whenever the boiler is emptied with a view to cleaning out. the above system is being advantageously applied in calais for removing the incrustations of boilers. the two poles of a battery of ten to twelve bunsen elements are applied to the ends of the boilers, and after thirty to forty hours the deposits fall from the sides to the bottom. when a boiler has been thus cleared, the formation of new deposits may be prevented by applying a much less energetic current under the same conditions. * * * * * alphabet designed by godfrey sykes. [illustration: suggestions in decorative art.--alphabet designed by godfrey sykes.] among the many designs which have been issued by the south kensington museum authorities is the alphabet which we have illustrated here to-day. the letters appear frequently among the decorations of the museum buildings, especially in the refreshment rooms and the ceramic gallery, where long inscriptions in glazed terra cotta form ornamental friezes. the alphabet has also been engraved to several sizes, and is used for the initial letters in the various official books and art publications relating to the museum, which are published by the science and art department.--_building news._ * * * * * old wrought iron gate. [illustration: old wrought iron gate] this gate forms the entrance to scraptoft hall, a building of the eighteenth century, now the seat of captain barclay, and which stands at about five miles from leicester, england.--_the architect._ * * * * * brief sanitary matters in connection with isolated country houses.[ ] [footnote : read before the boston society of civil engineers, april _journal a. of e. societies_.] by e.w. bowditch, c.e. i am unable to tell you what is generally considered the best practice, for i am not sure there are any definitely established rules; therefore i can only explain _my_ ways of doing such work, which, though i try to make as complete and at the same time as simple as possible, i know to be far from perfect. plumbing and drainage work has grown up unconsciously with my landscape gardening, and not finding any texts or practice that seemed wholly satisfactory, i have been forced to devise new arrangements from time to time, according to the requirements of the case in hand. to give all the details of house plumbing this evening, or any _one_ evening, would be impossible, for lack of time, and not worth while even if there was time, as much of it would prove matter of little or no interest. i will confine my remarks, therefore, to certain elements of the work where my practice differs, i believe, essentially from that of most engineers, and where perhaps my experience, if of no assistance to other members of the society, may excite their friendly criticism in such a way as to help me. there are two kinds of country places that i am liable to be called upon to prescribe for: _first._ a new place where nothing has been arranged. _second._ an old place where the occupants have been troubled either by their outside arrangements or by fixtures or pipes within. under the first head let us suppose a small tract of perhaps two acres of land in some inland town, where the family intends to live but six months in the year, though they are liable to reside there the whole twelve. there are no sewers and no public water. the soil is a stiff, retentive clay, rather wet in spring. the desire is expressed to have plumbing and drainage that shall be as inexpensive as possible, but that shall be entirely safe. in considering the arrangements inside the house, i find myself in the same predicament as the french surgeon, a specialist upon setting the bones of the arm, who, when a patient was brought him with his right arm broke, expressed his sorrow at being unable to be of assistance, as his specialty was the left arm. i have endeavored to post myself thoroughly upon house plumbing, but confess to only knowing partially about the wastes; the supplies i do not feel competent to pass upon. one class of annoyance caused by plumbing, perhaps the principal one, is due to the soil pipe or some of its fittings. second quality of iron, poor hanging, insufficient calking, careless mechanics, putty, cement, rag, or paper joints--all these and a dozen other things are liable to be sources of trouble. subordinate wastes are apt to be annoying, occasionally, too, to a less extent. the mechanical work can always be superintended, and within certain limits may be made secure and tight; not so easy, however, with the materials. there is seldom a valid excuse for ever making waste pipes, within a building, of anything but metal. earthen tile is frequently used; also, to a limited extent, brick, stone, and wood; twice i have found canvas--all these, however, are inferior, and should never be accepted or specified. the writer believes that at the present time, hereabouts, lead and iron are more used for wastes than any other materials, and are found the most satisfactory on the whole. one or two arrangements, relative to the wastes, i have made use of that are not, so far as known, in general use, and that may not be the best, though they have served me many good turns, and i have not succeeded in devising any better. soil pipe, as it is usually put in, is apt to be of cast iron, four inches in diameter, and is known in the market as "heavy" or "extra heavy." for some years the tar-coated or black enameled pipe has been the favorite, as being the more reliable, the writer in common with others making use of the same freely, until one day a cracked elbow, tar coated, was detected. since that time plain, untarred pipe has been specified, and subjected to the so-called kerosene test, which consists of swabbing out each pipe with kerosene or oil and then allowing it to stand for a few hours. a moment's thought will convince any one that when a pipe is asphalted or tar coated it is very difficult to detect either sand holes or small cracks, and the difficulty of proper calking is increased, as lead does not cling so well to the tar as to plain iron. at present, the kerosene test, so far as the writer is concerned, is a misnomer, because raw linseed oil is used exclusively as giving more satisfactory results, and being less troublesome to apply. i have here a length of the ordinary "heavy " commercial soil pipe, plain, and selected at random. yesterday noon i had it oiled at my office, in order to be ready for to-night, and you see, by the chalk marks i have made, just where the leaks were and their area. i may say here that a sound pipe of this caliber and standard weight is the exception rather than the rule, and it was selected for this experiment merely to try and show the reaction a little better than the heavier pipe might. experiments of this nature i have carried along for the past two years, and i am glad to say that, since i began, the quality of the soil pipe furnished by the dealers for my work seems appreciably better than at first. whether the poorer pipe is still made and sold to other customers i have no means of knowing; probably it is, however. a large quantity of the pipe is now being tested at my suggestion by the superintendent of construction of the johns hopkins hospital, at baltimore. i have not yet heard the results from him, but doubtless they will be interesting. a brief summary of the results may be of some interest. the different makers of soil pipe generally used by plumbers hereabouts are: mott & company, abendroth, blakslee, dighton, phillips & weeden, and bartlett, hayward & co. on " extra heavy pipe my results have been as follows: percentage passed as good, single hub. per ct. to per ct. percentage passed as good, double. per ct. to per ct. percentage passed special castings, including y's and t's. per ct. " pipe extra heavy: percentage passed as good, single hub. per ct. to per ct. percentage passed as good, double. no record. percentage special castings, including y's and t's. per ct. it has been stated to me by dealers that the tar coating does away with the necessity of any such test as the oil; while i am not prepared to acknowledge or deny the statement, it is well known that much poor pipe is tar-coated and sold in the market as good, and when coated it is almost impossible to detect any but _very_ defective work. the price customers are obliged to pay for soil pipe, either "heavy" or "extra heavy," is very high indeed, even taking off the discounts, and amounts (as i figure it) to $ per long ton for " pipe. the present rate for the best water pipe of the same caliber is about $ (now $ ) per long ton, and the additional charge for soil pipe should guarantee the very best iron in the market, though it appears to be rarely furnished. it is asserted that all soil pipe is tested to a -pound water pressure. i beg leave to question the absolute truth of this, unless it be acknowledged that pipe is sold indiscriminately, whether it bears the test or not, for more than once i have found a single length of soil pipe ( feet) that could not bear the pressure of a column of water of its own height without leaking. having obtained a satisfactory lot of soil pipe and fittings, the next trouble comes with the lead calking. unfortunately, it is frequently found that very shallow joints are made instead of deep ones, and hard lead used instead of soft. my rule is, soft lead, two runnings and two calkings. by soft lead i mean pig lead, and by hard lead i mean old pipe and scrap lead that may have been melted a dozen times. incidentally it may be remarked that it is quite difficult to calk a tight joint on the heavy pipe; the process will crack the hub. the fixtures used in a house are of minor importance--there are dozens of good patterns of every class. if they are carefully put in, and provided with suitable traps placed just as close to the fixture as possible, the result will usually be satisfactory. very few instances occur where traps are placed as close to the fixtures they serve as they might be, and yet a very short length of untrapped pipe, when fouled, will sometimes smell dreadfully. a set bowl with trap two feet away may become in time a great nuisance if not properly used. a case in point where the fixture was used both as a bowl and a urinal was in a few months exceedingly offensive--a fact largely (though not wholly) due to its double service. i have never met two sanitarians who agreed upon the same water-closets, bowls, faucets, traps, etc. of course, the soil pipe will be carried, of full size, through the roof, and sufficiently high to clear all windows. avoid multiplicity of fixtures or pipes; cut off all fixtures not used at least twice a week, lest their traps dry out; have all plumbing as simple as possible, and try and get it all located so that outside air can be got directly into all closets and bath-rooms. as far as possible, set your fixtures in glass rather than tiles or wood. carry the lower end of the main drain at least five feet beyond the cellar walls of the building, of cast iron. let us now look at the outside work. the main drain (carrying everything except the kitchen and pantry sinks) goes through a ventilated running trap. an indirect fresh air inlet is provided on the house side of the trap (example), to prevent annoyance from puffing or pumping, or, better still, a pipe corresponding to the soil pipe is carried up on the outside of the house. the running trap ventilator should be of the same diameter as the main drain ( inch), and serve as a main drain vent also. carry this pipe on the outside of the house as high as the top of the chimney. a grease-trap should be provided for the kitchen and pantry sinks. formerly my custom was to put in brick receptacles; it is now to put in portland cement traps (henderson pattern), though perhaps i may succeed in devising a cast-iron one that will answer better. the brick ones were occasionally heaved by the frost, and cracked; the portland cement ones answer better, and when thoroughly painted with red lead do not soak an appreciable quantity of sewage to be offensive, but are too high priced ($ each). i have made one or two patterns for cast-iron ones, but none as yet that i feel satisfied with. beyond the running trap an akron pipe should convey the sewage to a tank or cesspool. our supposable case is the second most difficult to take care of. the worst would be ledge. we have to contend with, however, hard, wet, impervious clay. the best way undoubtedly is to underdrain the land, and then to distribute the sewage on the principle of intermittent downward filtration. this is rather expensive, and a customer is rarely willing to pay the bills for the same. i should always advise it as the best; but where not allowed to do so, i have had fair success with shallow french drains connecting with the tank or cesspool. siphon tanks, such as are advised by many sanitarians, that were used first in this country, i believe, by mr. waring, i have not been very successful with. obstructions get into the siphon and stop it up, or it gets choked with grease. i prefer a tight tank, provided with a tell-tale, and that is to be opened either by a valve operated by hand, or that is arranged with a standing overflow like a bath tub, and that can be raised and secured by a hook. * * * * * sanitary cooking.[ ] [footnote : read before the indiana state sanitary society, seymour, march , .--_the sanitarian._] by virginia l. oppenheimer, m.d., seymour, ind. "we may live without poetry, music, and art, we may live without conscience, and live without heart, we may live without friends, we may live without books, but civilized man cannot live without cooks. "we may live without books-- what is knowledge but grieving? we may live without hope-- what is hope but deceiving? we may live without love--what is passion but pining? but where is the man that can live without dining?" thus saith the poet, and forthwith turns the world over into the hands of the cook. and into what better hands could you fall? to you, my fat, jolly, four-meals-a-day friend, mr. gourmand, but more especially to _you_, my somber, lean, dyspeptic, two-meals-a-day friend, mr. grumbler, the cook is indeed a valuable friend. the cook wields a scepter that is only second in power to that of love; and even love has become soured through the evil instrumentality of the good-looking or bad-cooking cook. this is no jest, it is a very sad fact. now, the question arises, how can the cook preserve the health of her patrons, maintain happiness in the family, and yet not throw the gourmands into bankruptcy? very simple, i assure you. . you must have _the_ cook. i mean by this, that not every one can occupy that important office. the greatest consideration in the qualities of a cook is, does she like the work? no one can fulfill the duties of any noteworthy office unless he labors at them with vim and willingness. . you must have good articles of food originally. . as our honest iago said, "you must have change." when one arrives at adult age, he should have learned by experience what articles of food _do_, and what articles of food do _not_, agree with him, and to shun the latter, no matter how daintily served or how tempting the circumstances. the man who knows that _pates de foie gras_, or the livers of abnormally fattened geese, disagree with him, and still eats them, is not to be pitied when all the horrors of dyspepsia overtake him. the cooking of any article of food has evidently much, very much, to do with its digestibility. it is not the purpose of this paper to teach cooking, but merely to give some general hints as to the best as well as the simplest methods of preparing staple articles of food. the same articles of food can and should be prepared differently on each day of the week. changes of diet are too likely to be underestimated. by constant change the digestive organs in the average person are prevented from having that repulsion of food which, to a greater or less extent, is likely to result from a sameness of diet continued for a long time. we often hear from our scientific men that this or that article of food is excellent for muscle, another for brain, another for bone, etc., etc. now, stubborn facts are like stone walls, against which theories often butt out their beauty and their power. it is well known to almost every one nowadays that _well-cooked_ food, whether it be potatoes, meat and bread, fish, or anything else worthy the name of food, will well maintain, indefinitely, either the philosopher or the hodcarrier. many of you know, and all of you ought to know, that the principal ingredients of nearly all our foods are starch and albumen. starch is the principal nutritive ingredient of vegetables and breadstuffs. albumen is the principal ingredient of meats, eggs, milk, and other animal derivatives. starch never enters the system as starch, but must first be converted into sugar either in the body or out of it. the process of this transformation of starch into sugar is beautifully exemplified in certain plants, such as the beet, the so-called sugar cane, and other growths. the young plant is, to a great extent, composed of starch; as the plant grows older, a substance is produced which is called _diastase_. through the influence of this _diastase_ the starch is converted into a peculiar non-crystallizable substance called _dextrine_, and as the plant matures, this dextrine is transformed into crystallizable sugar. "dextrine is a substance that can be produced from starch by the action of dilute acids, alkalies, and malt extract, and by roasting it at a temperature between ° and ° f., till it is of a light brown color, and has the odor of overbaked bread." a simple form of dextrine may be found in the brown crust of bread--that sweetish substance that gives the crust its agreeable flavor. pure dextrine is an insipid, odorless, yellowish-white, translucent substance, which dissolves in water almost as readily as sugar. as stated above, it is easily converted into _dextrose_, or _glucose_, as it is usually named. this _glucose_ is often sold under the name of sugar, and is the same against which so many of the newspapers waged such a war a year or two ago. these critics were evidently, for the most part, persons who knew little about the subject. glucose, if free from sulphuric acid or other chemicals, is as harmless as any other form of sugar. most of our candies contain more or less of it, and are in every way as satisfactory as when manufactured wholly from other sugars. it is, therefore, self-evident that, as sugar is a necessary article of food, the process which aids the transformation of our starchy foods must necessarily aid digestion. do not understand me to say by this that, if all our starchy foods were converted into sugar, their digestion would thereby be completed. as i stated a moment ago, this sweet food, if taken into the stomach day after day, would soon cause that particular organ to rebel against this sameness of diet. in order the more clearly to illustrate this point, i will briefly show you how some of the every-day articles of food can be each day differently prepared, and thus be rendered more palatable, and, as a consequence, more digestible; for it is a demonstrated fact that savory foods are far more easily digested than the same foods unsavored. the art of serving and arranging dishes for the table is an accomplishment in itself. it is very reasonable that all things that go to make up beauty and harmony at the dinner table should add their full quota to the appetite, and, i was about to say, "to the digestion;" but will qualify the statement by saying, to the digestion if the appetite be not porcine. our commonest article of food is the _potato_. let us see how potatoes--which contain only twenty per cent. of starch, as against eighty-eight per cent. in rice, and sixty-six per cent. in wheat flour--can be prepared as just mentioned. we will look for a moment at the manner in which they are usually served by the average cook: , boiled with their jackets on; , roasted in the embers; , roasted with meat; , fried; , mashed; , salad. . potatoes boiled in their jackets are excellent if properly prepared. but there's the rub. the trouble is, they are too often allowed to boil slowly and too long, and thus become water-soaked, soggy, and solid, and proportionately indigestible. they should be put over a brisk fire, and kept at a brisk boil till done; then drain off the water, sprinkle a little salt over them, and return to the fire a moment to dry thoroughly, when you will find them bursting with their white, mealy contents. . roasted potatoes are general favorites, and very digestible. a more agreeable flavor is imparted to them if roasted in hot embers (wood fire), care being used to keep them covered with the hot embers. . fried potatoes, as they are very generally served, are almost as digestible as rocks, but not so tempting in all their grease-dripping beauty as the latter. many of you have doubtless seen the potatoes neatly sliced and dumped into a frying pan full of hot lard, where they were permitted to sink or float, and soak and sob for about a half hour or more. when served, they presented the picturesque spectacle of miniature potato islands floating at liberty in a sea of yellow grease. now, if any of you can relish and digest such a mess as that, i would advise you to leave this clime, and eat tallow candles with the esquimaux. if you are fond of fried potatoes, cook them in this way: take what boiled potatoes are left from breakfast or dinner; when cold, remove the jackets, and cut into thin slices, season with salt, pepper, and a little cayenne; have ready a hot frying pan, with enough meat drippings or sweet lard to cover the bottom; put in the potatoes and fry a rich brown, stirring constantly with a knife to prevent burning. serve very hot. . mashed potatoes will be discussed further on. . potato salads are appetizing and piquant, because they are usually made up with strong condiments, onions, etc. they are, therefore, not very digestible in themselves. nevertheless, they are so palatable that we cannot easily dispense with them; but, after eating them, if you expect to have inward peace, either split wood, walk eight and a half miles, or take some other light exercise. more palatable, and proportionately digestible, are the following methods of cooking this useful vegetable: , saratoga potatoes; , a la maitre d'hotel; , potato croquettes; , potatoes and cream; , a la lyonnaise. . for _saratogas_, pare and slice your potatoes as thin as possible, dropping them into cold water in which is dissolved a tiny piece of alum to make them crisp. let them remain in the water for an hour or longer. drain, and wipe perfectly dry with a tea towel. have ready a quantity of boiling lard. drop them in, and fry a delicate brown. drain all grease from them, sprinkle with salt, and serve. here, in the crisp slices, you will have the much desired dextrine. or, in other words, your potato is already half digested. eat three or four potatoes prepared thus, and you feel no inconvenience; but how would you feel did you devour three soggy, water-soaked _boiled_ potatoes? . for _a la maitre d'hotel_, pare the potatoes, cut into pieces half an inch wide, and the length of the potato; drop into cold water until wanted (an hour or so); then drain, and fry in boiling lard. just as they begin to brown take them out with a skimmer; let them slightly cool; then put back, and fry a rich brown. this makes them puff up, and very attractive. . for _croquettes_, take finely mashed potatoes, and mix with salt, pepper, and butter, and sweet milk or cream enough to moisten thoroughly. mix with this one well-beaten egg, and form into small balls, taking care to have them smooth. have ready one plate with a beaten egg upon it, and another with cracker crumbs. dip each ball into the egg, and then into the crumbs, and brown nicely. lay the croquettes on brown paper first, to get rid of any superfluous grease, then serve on a napkin. . _potatoes and cream_ are prepared by mincing cold boiled potatoes fine, putting them in a spider with a little melted butter in it, and letting them fry slightly, keeping them well covered. add a very small piece of fresh butter, season with pepper and salt, and pour over them cream or rich milk. let them boil up once, and serve. this is a very nice dish, and may be safely taken into delicate stomachs. . _a la lyonnaise_ is prepared as follows: take five cold potatoes, one onion, butter, salt, and pepper. slice the onion finely, and fry it in butter until it begins to take color; add the sliced potatoes, salt and pepper to taste, and keep shaking the saucepan until they are somewhat browned. serve hot. a few random remarks about the preparation of albuminous foods. if the albumen in food is hardened by prolonged cooking, it is rendered _less_ instead of more digestible. therefore, the so-called _well-cooked_ meats are really _badly-cooked_ meats. meats should be only half done, or rare. to do this properly, it is necessary to cook with a quick fire. steaks should be broiled, not fried. i am in accord with a well-known orator, who said, recently, that "the person who fries a steak should be arrested for cruelty to humanity." some few meats should always be well cooked before eating.[ ] [footnote : these are the exceptions. pork, on account of the prevalence of disease in hogs, should be well done.] the same law holds good with eggs as with meats. a hard-boiled egg is only fit for the stomach of an ostrich; it was never intended by nature to adorn the human stomach. there are very many ways of preparing eggs--by frying, baking, poaching, shirring, etc. i will only describe briefly a few simple methods of making omelets. in making this elegant dish, never use more than three eggs to an _omelet_. plain omelet: separate the whites and yolks; add a teaspoonful of water to the whites, and beat to a stiff froth; add to the yolks a teaspoonful of water, and beat until light; then season with salt, and about two tablespoonfuls of cream or rich milk. have your spider very hot; turn your whites and yolks together, and stir lightly to mix them; place a bit of butter in the spider, and immediately pour in your eggs. when set (which takes from ten to twenty seconds, and be careful that it does not brown too much), fold together in a half moon, remove it, sprinkle with powdered sugar, and serve on a hot plate. it should be eaten immediately. fruit omelets are made by placing preserved fruits or jellies between the folds. baked omelets are prepared as above, with the addition of placing in the oven and allowing to brown slightly. french omelet is prepared in this way: take a half cup of boiling milk with a half teaspoonful of butter melted in it; pour this over one-half cup of bread crumbs (light bread); add salt, pepper, and the yolks of three eggs beaten very light; mix thoroughly; and lastly, add the whites whipped to a stiff froth. stir lightly, and fry in butter. when nearly done, fold together in a half moon, and serve immediately. and thus we might continue _ad infinitum_, but, as was stated before, it is not my object to instruct you in special cooking, but to illustrate in this manner how much easier it is, to both the cook and your stomachs, to prepare healthful dishes than to do the reverse. * * * * * time required to digest different foods. _the monitor de la salud_ contains in a recent number the results of some experiments lately made by e. jessen on the time required for the digestion of certain kinds of food. the stomach of the person on whom the experiments were made was emptied by means of a pump; grammes, equal to , grains, or about - / ounces, of meat, finely chopped and mixed with three times the quantity of water, were introduced. the experiment was considered ended when the matter, on removal by the pump, was found to contain no muscular fibre. it will be remembered that the gramme weighs nearly - / grains, and the cubic centigramme is equal to gramme. the - / ounces of meat were therefore mixed with nearly eight ounces of water, before being introduced into the stomach. the results were as follows: beef, raw, and finely chopped. hours. " half cooked. ½ " " well cooked. " " slightly roasted. " " well roasted. " mutton, raw. " veal. ½ " pork. " the digestibility of milk was examined in the same way. the quantity used was regulated so that the nitrogen should be the same as in the grammes of beef. cubic centimeters, nearly sixteen ounces, of cow's milk, not boiled, required. ½ hours cubic centimeters, boiled. " " " sour. ½ " " " skimmed. ½ " " " goat's milk, not boiled. ½ " * * * * * the organization and plan of the united states geological survey.[ ] [footnote : communicated to the national academy of sciences at the october meeting in .] by j.w. powell. a scientific institution or bureau operating under government authority can be controlled by statute and by superior administrative authority but to a limited extent. these operations are practically carried on by specialists, and they can be controlled only in their financial operations and in the general purposes for which investigations are made. their methods of investigation are their own--originate with themselves, and are carried out by themselves. but in relation to the scientific operations of such a government institution, there is an unofficial authority which, though not immediately felt, ultimately steps in to approve or condemn, viz., the body of scientific men of the country; and though their authority is not exercised antecedently and at every stage of the work, yet it is so potent that no national scientific institution can grow and prosper without their approval, but must sooner or later fall and perish unless sustained by their strong influence. as director of the geological survey, i deeply realize that i owe allegiance to the scientific men of the country, and for this reason i desire to present to the national academy of sciences the organization and plan of operations of the survey. a topographic map of the united status. sound geologic research is based on geography. without a good topographic map geology cannot even be thoroughly studied, and the publication of the results of geologic investigation is very imperfect without a good map; but with a good map thorough investigation and simple, intelligible publication become possible. impelled by these considerations, the survey is making a topographic map of the united states. the geographic basis of this map is a trigonometric survey by which datum points are established throughout the country; that is, base-lines are measured and a triangulation extended therefrom. this trigonometric work is executed on a scale only sufficiently refined for map-making purposes, and will not be directly useful for geodetic purposes in determining the figure of the earth. the hypsometric work is based upon the railroad levels of the country. throughout the greater part of the country, there is a system of railroad lines, constituting a net-work. the levels or profiles of these roads have been established with reasonable accuracy, and as they cross each other at a multiplicity of points, a system of checks is afforded, so that the railroad surface of the country can be determined therefrom with all the accuracy necessary for the most refined and elaborate topographic maps. from such a hypsometric basis the reliefs for the whole country are determined, by running lines of levels, by trigonometric construction, and in mountainous regions by barometric observation. the primary triangulation having been made, the topography is executed by a variety of methods, adapted to the peculiar conditions found in various portions of the country. to a large extent the plane-table is used. in the hands of the topographers of the geological survey, the plane-table is not simply a portable draughting table for the field; it is practically an instrument of triangulation, and all minor positions of the details of topography are determined through its use by trigonometric construction. the scale on which the map is made is variable. in some portions of the prairie region, and in the region of the great plains, the topography and the geology alike are simple, and maps on a comparatively small scale are sufficient for practical purposes. for these districts it is proposed to construct the sheets of the map on a scale of - , , or about four miles to the inch. in the mountain regions of the west the geology is more complex, and the topography more intricate; but to a large extent these regions are uninhabited, and to a more limited extent uninhabitable. it would therefore not be wise to make a topographic or geologic survey of the country on an excessively elaborate plan. over much of this area the sheets of the map will also be constructed on a scale of - , , but in special districts that scale will be increased to - , , and in the case of important mining districts charts will be constructed on a much larger scale. in the eastern portion of the united states two scales are adopted. in the less densely populated country a scale of - , is used; in the more densely populated regions a scale of - , is adopted, or about one mile to the inch. but throughout the country a few special districts of great importance, because of complex geologic structure, dense population, or other condition, will require charts on still larger scales. the area of the united states, exclusive of alaska, is about three million square miles, and a map of the united states, constructed on the plan set forth above, will require not less than , sheets. it may ultimately prove to require more than that, from the fact that the areas to be surveyed on the larger scale have not been fully determined. besides the number of sheets in the general map of the united states, there will be several hundred special maps on large scales, as above described. such is a brief outline of the plan so far as it has been developed at the present time. in this connection it should be stated that the map of the united states can be completed, with the present organization of the geological survey, in about years; but it is greatly to be desired that the time for its completion may be materially diminished by increasing the topographic force of the geological survey. we ought to have a good topographic map of the united states by the year . about one-fifth of the whole area of the united states, exclusive of alaska, has been completed on the above plan. this includes all geographic work done in the united states under the auspices of the general government and under the auspices of state governments. the map herewith shows those areas that have been surveyed by various organizations on such a scale and in such a manner that the work has been accepted as sufficient for the purposes of the survey. much other work has been done, but not with sufficient refinement and accuracy to be of present value, though such work subserved its purpose in its time. an examination of the map will show that the triangulation of the various organizations is already largely in advance of the topography. the map of the united states will be a great atlas divided into sheets as above indicated. in all of those areas where the survey is on a scale of - , , a page of the atlas will present an area of one degree in longitude and one degree in latitude. where the scale is - , , a page of the atlas-sheet will represent one-fourth of a degree. where the scale is - , , the atlas-sheet will represent one-sixteenth of a degree. the degree sheet will be designated by two numbers--one representing latitude, the other longitude. where the sheets represent fractional degrees, they will be labeled with the same numbers, with the addition of the description of the proper fractional part. the organization, as at present established, executing this work, is as follows: first, an astronomic and computing division, the officers of which are engaged in determining the geographic coordinates of certain primary points. second, a triangulation corps engaged in extending a system of triangulation over various portions of the country from measured base-lines. third, a topographic corps, organized into twenty-seven parties, scattered over various portions of the united states. such, in brief outline, is the plan for the map of the united states, and the organization by which it is to be made. mr. henry gannett is the chief geographer. paleontology. before giving the outline of the plan for the general geologic survey, it will be better to explain the accessory plans and organizations. there are in the survey, as at present organized, the following paleontologic laboratories: . a laboratory of vertebrate paleontology for formations other than the quaternary. in connection with this laboratory there is a corps of paleontologists. professor o.c. marsh is in charge. . there is a laboratory of invertebrate paleontology of quaternary age, with a corps of paleontologists, mr. wm. h. dall being in charge. . there is a laboratory of invertebrate paleontology of cenozoic and mesozoic age, with a corps of paleontologists. dr. c.a. white is in charge. . there is a laboratory of invertebrate paleontology of paleozoic age, with a corps of paleontologists. mr. c.d. walcott is in charge. . there is a laboratory of fossil botany, with a corps of paleobotanists, mr. lester f. ward being in charge. the paleontologists and paleobotanists connected with the laboratories above described, study and discuss in reports the fossils collected by the general geologists in the field. they also supplement the work of the field geologists by making special collections in important districts and at critical horizons; but the paleontologists are not held responsible for areal and structural geology on the one hand, and the geologists are not held responsible for paleontology on the other hand. in addition to the large number of paleontologists on the regular work of the geological survey, as above described, several paleontologists are engaged from time to time to make special studies. chemistry. there is a chemic laboratory attached to the survey, with a large corps of chemists engaged in a great variety of researches relating to the constitution of waters, minerals, ores, and rocks. a part of the work of this corps is to study the methods of metamorphism and the paragenesis of minerals, and in this connection the chemists do work in the field; but to a large extent they are occupied with the study of the materials collected by the field geologists. professor f.w. clarke is in charge of this department. physical researches. there is a physical laboratory in the survey, with a small corps of men engaged in certain physical researches of prime importance to geologic philosophy. these researches are experimental, and relate to the effect of temperatures, pressures, etc., on rocks. this laboratory is under the charge of the chief chemist. lithology. there is a lithologic laboratory in the survey, with a large corps of lithologists engaged in the microscopic study of rocks. these lithologists are field geologists, who examine the collections made by themselves. statistics. there is in the survey a division of mining statistics, with a large corps of men engaged in statistic work, the results of which are published in an annual report entitled "mineral resources." mr. albert williams, jr., is the chief statistician of the survey. illustrations. there is in the survey a division organized for the purpose of preparing illustrations for paleontologic and geologic reports. mr. w.h. holmes is in charge of this division. illustrations will not hereafter be used for embellishment, but will be strictly confined to the illustration of the text and the presentation of such facts as can be best exhibited by figures and diagrams. all illustrations will, as far as possible, be produced by relief methods, such as wood-engraving, photo-engraving, etc. as large numbers of the reports of the survey are published, this plan is demanded for economic reasons; but there is another consideration believed to be of still greater importance; illustrations made on stone cannot be used after the first edition, as they deteriorate somewhat by time, and it is customary to use the same lithographic stone for various purposes from time to time. the illustrations made for the reports of the survey, if on relief-plates that can be cheaply electrotyped, can be used again when needed. this is especially desirable in paleontology, where previously published figures can be introduced for comparative purposes. there are two methods of studying the extinct life of the globe. fossils are indices of geological formations, and must be grouped by formations to subserve the purpose of geologists. fossils also have their biologic relations, and should be studied and arranged in biologic groups. under the plan adopted by the survey, the illustrations can be used over and over again for such purposes when needed, as reproduction can be made at the small cost of electrotyping. these same illustrations can be used by the public at large in scientific periodicals, text-books, etc. all the illustrations made by the geological survey are held for the public to be used in this manner. library. the library of the survey now contains more than , volumes, and is rapidly growing by means of exchanges. it is found necessary to purchase but few books. the librarian, mr. c.c. darwin, has a corps of assistants engaged in bibliographic work. it is proposed to prepare a catalogue of american and foreign publications upon american geology, which is to be a general authors' catalogue. in addition to this, it is proposed to publish bibliographies proper of special subjects constituting integral parts of the science of geology. publications. the publications of the survey are in three series: annual reports, bulletins, and monographs. the annual report constitutes a part of the report of the secretary of the interior for each year, but is a distinct volume. this contains a brief summary of the purposes, plans, and operations of the survey, prepared by the director, and short administrative reports from the chiefs of divisions, the whole followed by scientific papers. these papers are selected as being those of most general interest, the object being to make the annual report a somewhat popular account of the doings of the survey, that it may be widely read by the intelligent people of the country. of this , copies are published as a part of the secretary's report, and are distributed by the secretary of the interior, senators, and members of the house of representatives; and an extra edition is annually ordered of , copies, distributed by the survey and members of the senate and house of representatives. four annual reports have been published; the fifth is now in the hands of the printer. the bulletins of the survey are short papers, and through them somewhat speedy publication is attained. each bulletin is devoted to some specific topic, in order that the material ultimately published in the bulletins can be classified in any manner desired by scientific men. nine bulletins have been published, and seven are in press. the bulletins already published vary in size from to pages each; they are sold at the cost of press-work and paper, and vary in price from five to twenty cents each; , copies of each bulletin are published; , are distributed by congress, , are held for sale and exchange by the geological survey. the monographs of the survey are quarto volumes. by this method of publication the more important and elaborate papers are given to the public. six monographs, with two atlases, have been issued; five monographs, with two atlases, are in press; , copies of each monograph are distributed by congress; , are held for sale and exchange by the survey at the cost of press-work, paper, and binding. they vary in price from $ . to $ . the chiefs of divisions supervise the publications that originate in their several corps. the general editorial supervision is exercised by the chief clerk of the survey, mr. james c. pilling. general geology. in organizing the general geologic work, it became necessary, first, to consider what had already been done in various portions of the united states; and for this purpose the compilation of a general geologic map of the united states was begun, together with a thesaurus of american formations. in addition to this the bibliographic work previously described was initiated, so that the literature relating to american geology should be readily accessible to the workers in the survey. at this point it became necessary to consider the best methods of apportioning the work; that is, the best methods of dividing the geologic work into parts to be assigned to the different corps of observers. a strictly geographic apportionment was not deemed wise, from the fact that an unscientific division of labor would result, and the same classes of problems would to a large extent be relegated to the several corps operating in field and in the laboratory. it was thought best to divide the work, as far as possible, by subject-matter rather than by territorial areas; yet to some extent the two methods of division will coincide. there are in the survey at present: first, a division of glacial geology, and prof. t.c. chamberlin, formerly state geologist of wisconsin is at its head, with a strong corps of assistants. there is an important field for which definite provision has not yet been made, namely, the study of the loess that constitutes the bluff formations of the mississippi river and its tributaries. but as this loess proves to be intimately associated with the glacial formations of the same region, it is probable that it will eventually be relegated to the glacial division. perhaps the division may eventually grow to such an extent that its field of operations will include the whole quaternary geology. second, a division of volcanic geology is organized, and capt. clarence e. dutton, of the ordnance corps of the army, is placed in charge, also with a strong corps of assistants. third and fourth, two divisions have been organized to prosecute work on the archæan rocks, embracing within their field not only all rocks of archæan age, but all metamorphic crystalline schists, of whatever age they may be found. the first division has for its chief prof. raphael pumpelly, assisted by a corps of geologists, and the field of his work is the crystalline schists of the appalachian region, or eastern portion of the united states, extending from northern new england to georgia. he will also include in his studies certain paleozoic formations which are immediately connected with the crystalline schists and involved in their orographic structure. the second division for the study of this class of rocks is in charge of prof. roland d. irving, with a corps of geologists, and his field of operation is in the lake superior region. it is not proposed at present to undertake the study of the crystalline schists of the rocky mountain region. fifth, another division has been organized for the study of the areal, structural, and historical geology of the appalachian region, extending from the atlantic, westward, to the zone which separates the mountain region from the great valley of the mississippi. mr. g.k. gilbert has charge of this work, and has a large corps of assistants. sixth, it seemed desirable, partly for scientific reasons and partly for administrative reasons, that a thorough topographic and geologic survey should be made of the yellowstone park, and mr. arnold hague is in charge of the work, with a corps of assistants. when it is completed, his field will be expanded so as to include a large part of the rocky mountain region, but the extent of the field is not yet determined. it will thus be seen that the general geologic work relating to those areas where the terranes are composed of fossiliferous formations is very imperfectly and incompletely organized. the reason for this is twofold: first, the work cannot be performed very successfully until the maps are made; second, the geological survey is necessarily diverting much of its force to the construction of maps, and cannot with present appropriations expand the geologic corps so as to extend systematic work in the field over the entire country. economic geology. under the organic law of the geological survey, investigations in economic geology are restricted to those states and territories in which there are public lands; the extension of the work into the eastern portion of the united states included only that part relating to general geology. two mining divisions are organized. one, in charge of mr. george f. becker, with headquarters at san francisco, california, is at the present time engaged in the study of the quicksilver districts of california. the other, under charge of mr. s.f. emmons, with headquarters at denver, colorado, is engaged in studying various mining districts in that state, including silver, gold, iron, and coal areas. each division has a corps of assistants. the lignite coals of the upper missouri, also, are under investigation by mr. bailey willis, with a corps of assistants. employes. the employes on the geological survey at the close of september, , were as follows: appointed by the president, by and with the advice and consent of the senate (director), . appointed by the secretary of the interior, on the recommendation of the director of the survey, . employed by the chiefs of parties in the field, . appointments. three classes of appointments are made on the survey. the statute provides that "the scientific employes of the geological survey shall be selected by the director, subject to the approval of the secretary of the interior, exclusively for their qualifications as professional experts." the provisions of this statute apply to all those cases where scientific men are employed who have established a reputation, and in asking for their appointment the director specifically states his reasons, setting forth the work in which the person is to be employed, together with his qualifications, especially enumerating and characterizing his published works. on such recommendations appointments are invariably made. young men who have not established a reputation in scientific research are selected through the agency of the civil service commission on special examination, the papers for which are prepared in the geological survey. about one-half of the employes, however, are temporary, being engaged for services lasting for a few days or a few months only, largely in the field, and coming under two classes: skilled laborers and common laborers. such persons are employed by the director or by the heads of divisions, and are discharged from the service when no longer needed. it will be seen that the director is responsible for the selection of the employes, directly for those whom he recommends for appointment, and indirectly for those selected by the civil service commission, as he permanently retains in the work. if, then, improper persons are employed, it is wholly the director's fault. the appropriations made for the geological survey for the fiscal year ending june , , aggregate the sum of $ , . this sum does not include the amount appropriated for ethnologic researches--$ , . nor are the expenses for engraving and printing paid for from the above appropriations, but from appropriations made for the work under the direction of the public printer. it is estimated that the amount needed for engraving and printing for the same fiscal year will exceed $ , . the relation of the government survey to state surveys. the united states geological survey is on friendly relations with the various state surveys. between the government survey and the state survey of new york, there is direct co-operation. the state survey of pennsylvania has rendered valuable assistance to the government survey, and negotiations have been entered into for closer relations and more thorough co-operation. the state surveys of north carolina, kentucky, and alabama are also co-operating with the government survey, and the director of the government survey is doing all within his power to revive state surveys. the field for geologic research in the united states is of great magnitude, and the best results can be accomplished only by the labors of many scientific men engaged for a long term of years. for this reason it is believed that surveys should be established in all of the states and territories. there is work enough for all, and the establishment of local surveys would greatly assist the general work prosecuted under the auspices of the government, and prevent it from falling into perfunctory channels. its vigor and health will doubtless be promoted by all thorough local research. it may be of interest to scientific men to know that the director finds that in presenting the general results, interests, and needs of the survey to congress, and to committees of congress, a thorough appreciation of the value of scientific research is shown by the statesmen of the country. questions relating to immediately economic values are asked, as they should be; but questions relating to sound administration, wise methods of investigation, and important scientific results are vigorously urged, and the principle is recognized that all sound scientific research conduces to the welfare of the people, not only by increasing knowledge, but ultimately by affecting all the industries of the people. * * * * * [the garden.] the sunflowers. [illustration: flower of helianthus argophyllus.] the genus helianthus is almost entirely north-american, and for the distinction and limitation of its species we are indebted to the labor of dr. asa gray, now universally recognized as the highest authority on north american plants. in the recently published second part of his "synoptical flora of north america" he has described thirty-nine species, six of which are annual. the synonyms and cross-naming adopted by previous authors have led to much confusion, which probably will not now be altogether cleared up, for dr. gray warns us that the characters of some of the species are variable, especially in cultivation. it may be added that some at least of the species readily form hybrids. there is always more or less difficulty with a variable genus in making garden plants fit wild specific types, but in the following notes i have described no kinds which i have not myself cultivated, selecting the best forms and giving them the names assigned severally by dr. gray to the species to which our garden plants seem to come nearest. [illustration: helianthus argophyllus, showing habit of growth.] _helianthus multiflorus_, or, according to asa gray, speaking botanically, h. decapetalus hort. var. multiflorus, is mentioned first, because it is the subject of the colored illustration. the name multiflorus is established by long usage, and perhaps was originally given in contrast to the few-flowered habit of h. annuus, for the type of the species is more floriferous than the variety of which asa gray says that it is "known only in cultivation from early times, must have been derived from decapetalus," a statement which gardeners would hardly have accepted on less indisputable authority, as they will all think the habit and appearance of the two plants widely different. the variety multiflorus has several forms; the commonest form is double, the disk being filled with ligules much shorter than those of the ray flowers, after the form of many daisy-like composites. in this double form the day flowers are often wanting. it is common also on old plants in poor soils to see double and single flowers from the same root. in the single forms the size of the flowers varies, the difference being due to cultivation as often as to kind. i have obtained by far the finest flowers by the following treatment: in early spring, when the young shoots are about an inch high, cut some off, each with a portion of young root, and plant them singly in deep rich soil, and a sheltered but not shaded situation. by august each will have made a large bush, branching out from one stalk at the base, with from thirty to forty flowers open at a time, each inches across. the same plants if well dressed produce good flowers the second season, but after that the stalks become crowded, and the flowers degenerate. the same treatment suits most of the perennial sunflowers. the following kinds are mentioned in the order in which they occur in asa gray's book: [illustration: helianthus multiflorus, showing habit of growth.] annuals. _h. argophyllus_ (white-leaved, not argyrophyllus, silver-leaved, as written in some catalogues).--an annual with woolly leaves, neater and less coarse than h. annuus, with which it is said soon to degenerate in gardens if grown together with it. _h. annuus._--the well known sunflower in endless varieties, one of the most elegant having pale lemon-colored flowers; these, too, liable to pass into the common type if grown in the same garden. [illustration: helianthus orgyalis, showing habit of growth in autumn.] _h. debilis var. cucumerifolius._--i have never seen the typical species, but the variety was introduced a few years ago by mr. w. thompson, of ipswich, from whose seed i have grown it. it becomes feet or feet high, with irregularly toothed deltoid leaves and spotted stalks, making a widely branched bush and bearing well-shaped golden flowers more than inches across, with black disks. it crosses with any perennial sunflower that grows near it, simulating their flowers in an annual form. i had a very fine cross with it and h. annuus, but the flowers of this produced no good seed. [illustration: jerusalem artichoke (helianthus tuberosus).] perennials. _h. orgyalis_ (the fathom-high sunflower).--the name is far within the true measure, which is often feet or feet. a very distinct species, increasing very slowly at the root and throwing all its growing efforts upward. the long linear ribbon leaves, often exceeding a foot, spreading in wavy masses round the tall stem, which has a palm-like tuft of them at the summit, are a more ornamental feature than the flowers, which are moderate in size and come late in the axils of the upper leaves. [illustration: helianthus annuus globulus fistulosus.] _h. angustifolius._--a neat and elegant species, which i first raised from seed sent by mr. w. thompson, of ipswich. it has a very branching habit quite from the base like a well-grown bush of the common wallflower. the flowers are abundant, about ½ inches across, with a black disk. the plant, though a true herb, never comes up in my garden with more than one stalk each year. [illustration: helianthus rigidus (syn. harpalium rigidum).] _h. rigidus_ is well known as the best of the perennial sunflowers, and has many synonyms, the commonest harpalium rigidum. it need not be described, but one or two things about it may be noted. the shoots, which come up a yard or more from last year's stalk, may be transplanted as soon as they appear without injury to the flowering, but if put back to the old center, the soil, which should be deep and light, ought to be enriched. the species is variable, and improved forms may be expected, as it produces seed in england. the number of ray flowers is often very large. i have one form which has several rows of them, nearly hiding the disk. a variety is figured in _botanical magazine_, tab. , , under the name of h. atro-rubens. another comes in the same series, tab. , , as h. diffusus. other synonyms are h. missuricus and h. missouriensis. its native range extends across north america in longitude, and covers many degrees of latitude. it likes a dry soil. in wet soil and wet seasons the flower-stalk is apt to wither in the middle, and the bud falls over and perishes prematurely. [illustration: common sunflower (h. annuus) showing habit of growth.] _h. lætiflorus._--under this name we grow in england a tall, much-branched, late flowering kind, with smooth and very stout and stiff stalks, sometimes black, sometimes green. it increases at the base of the stalks; it makes close growth, and shows little disposition to run at the root. the flowers are rather small, not more than inches across, but so durable and so well displayed by the numerous spreading branches as to make the plant very useful for late decoration. i own that i cannot identify this plant with the lætiflorus of asa gray, which he tells us resembles tall forms of h. rigidus, with rough stalks, and bears flowers with numerous rays ½ inches long. [illustration: flower of helianthus annuus.] _h. occidentalis._--recently introduced by mr. w. thompson, of ipswich, who gave me the plant two years ago. it is a neat species, growing about feet high, well branched, and producing at the end of july abundance of flowers about inches across. the lower leaves are small and broad, with long stalks, ovate in form. [illustration: helianthus multiflorus fl-pl.] _h. mollis_, so called from the soft white down with which the leaves are covered, grows about feet high. leaves large, ovate, and sessile; growth of the plant upright, with hardly any branches; flowers pale yellow, about inches across, not very ornamental. cultivated at kew, whence i had it. _h. giganteus_ grows feet high; stem much branched and disposed to curve. flowers about ½ inches across, produced abundantly in august; rays narrow and pointed, cupped, with the ends turning outward; leaves lanceolate and sessile; rootstock creeping, forming tuberous thickenings at the base of the stems, which asa gray tells us were "the indian potato of the assiniboine tribe," mentioned by douglas, who called the plant h. tuberosus. [illustration: full sized flower of helianthus multiflorus.] _h. maximiliani._--half the height of the last, which it resembles, but the stem is stouter, the leaves larger, as are also the flowers, which are produced later. it is not so floriferous and ornamental as the last. _h. lævigatus._--smooth stalked, very distinct, does not spread at the roots, which are composed of finer fibers than those of most of the genus; stalks slender and black, growing closely together, branched near the summit, feet high; leaves narrowly lanceolate and acute; flowers plentiful and about inches across; rays few, and disk small. we are warned that the following species are "difficult of extrication," either confluent or mixed by intercrossing. _h. doronicoides._--i place this the third in merit among perennial sunflowers, h. rigidus and h. multiflorus being first and second. it is feet or feet high, upright in growth, with many stalks. flowers ½ inches across, produced from the end of july to the end of september, bright golden yellow; leaves large, ovate, tapering from the middle to both ends; stalk leaves sessile and nearly connate, that is, clasping the stalk by their opposite base. the plant spreads rapidly by running rootstocks, and ripens seed in abundance. figured as h. pubescens in _botanical magazine_, tab. , . _h. divaricatus_ resembles the last, but is inferior, being a smaller plant in all parts, especially in the flowers, which come out a month later. the cauline leaves are stalked and diverge widely, which habit gives its name to the plant. a casual observer would hardly notice the difference between this species and the last, but when grown together the superiority of doronicoides as a garden plant is at once evident. _h. strumosus._--fully feet high; growth upright; rootstock less spreading than the last two; leaves on very short stalks, broadest at the base, ovate tapering by a long narrow point; flower disk narrow, but rays large and orange-yellow; flowers showy, inches across; they come out late in august. i had this plant from kew. the shape of the leaves would have led me rather to refer it to h. trachelifolius, a closely allied species. _h. decapetalus._--five feet high; flowers from end of july; makes a dense forest of weak, slender stalks, much branched at the top; spreads fast; leaves serrate, oblong-ovate, rather large; flowers abundant, pale yellow, about inches across; rays nearly always more than ten, in spite of the name. _h. tuberosus._--the well-known jerusalem artichoke; not a plant grown for ornament, being too coarse and late in flowering, but several things in its history may be mentioned, as dr. asa gray has spent labor and study over it. it is believed to have been cultivated by the natives before the discovery of america, and the edible tubers are thought to be a development of cultivation. forms of it without tuberous roots are found wild, but whether indigenous to the place or degenerate from cultivation was for long uncertain. several species of helianthus have a tendency to produce similar fleshy tubers at the top of the roots. dr. gray used to refer the origin of this species to h. doronicoides, but it is now believed by him to be a distinct species, though one of which it is difficult to identify with certainty the typical form. i omitted to say that the word helianthus is greek for sunflower. after several years' careful observation, i believe the notion that the flowers keep their face to the sun is quite a delusion. edge hall. c. wolley dod. * * * * * a quick filter.--the _druggists circular_ recommends chamois skin, free from thin places; cut it of the desired size; wash it in a weak solution of sal soda, or any alkali, to remove the grease, and rinse thoroughly in cold water before using. tinctures, elixirs, sirups, and even mucilages are filtered rapidly. a pint of the thickest sirup will run through in four or five minutes. by washing thoroughly after each time of using, it will last a long time. * * * * * lye's fuchsias. the group of fuchsias shown in our engraving represents a collection of nine specimens raised and exhibited by that well known cultivator, mr. james lye, of clyffe hall gardens, market lavington, at an exhibition held in bath in september last, and which received the first prize in the premier class for that number of plants. for many years past mr. lye has exhibited fuchsias at exhibitions held at bath, trowbridge, devizes, calne, chippenham, and elsewhere; on all occasions staging specimens of a high order of merit; but the plants appearing in our illustration were universally regarded as the best he had ever placed in an exhibition tent. so much were the committee of the bath show pleased with the specimens that they engaged the services of a photographer to make a picture of them on the spot; but after being two hours making the attempt, no satisfactory result occurred. after the plants were taken back to clyffe hall, they were photographed as seen in the illustration. some idea of their height and dimensions can be realized by a comparison with the stature of mr. lye, who is standing by his plants, and who is of average height. it should be mentioned that previous to being photographed they had traveled by road from market lavington to bath and back, a distance of miles, in addition to having been exhibited two days. they returned to their home apparently little the worse for wear, which immunity from harm is no doubt owing to the admirable system of tying adopted by mr. lye. it is sometimes said that the act of trying in the flowering shoots in this manner gives the plants a somewhat severely formal appearance, but there is an abundance of healthy foliage and a wonderful profusion of finely developed flowers, showing the most careful and painstaking cultivation. it is only those who are privileged to see these unrivaled plants who can appreciate them at their proper worth. it has been stated already that the varieties figured are all of mr. lye's own raising, which facts attests to the value of his seedlings, many of which he has produced. four of these are dark varieties, viz., bountiful, charming, elegance, and the hon. mrs. hay--the latter one of the oldest, but one of the freest, and scarcely without an equal for its great freedom of bloom. the remaining five are light varieties, viz., lye's favorite, harriet lye, star of wilts, pink perfection, and beauty of the west. [illustration: mr. lye's fuschias.] the specimens figured average from two to five years of age. it is really marvelous what mr. lye can do with a fuchsia in two years; and lest it might be supposed that he has plenty of glass accommodation, and can keep his plants under glass continuously, it is due to him it should be stated that he is very deficient in house accommodation, having but two small houses, in one of which (an old house) he winters his plants and brings them on until he can place them with safety in the open air in early summer. his method of treating the specimens as set forth in his own words may prove helpful to some of our readers: "after the plants have done flowering, say about the third week in october, i cut them back into the shape best fitted to form symmetrical specimens, and keep them dry for a week or ten days, to check the bleeding of sap which follows; after that i give a little water just to start them into growth, so as to make shoots about three-quarters of an inch in length, in order to keep the old wood active and living. i keep them in a cold house, and give but very little water until the first or second week in february, when i shake the old soil from the roots, and re-pot them into a fresh compost made up of three parts good loam, one part well decomposed manure, and one part leaf-mould and peat, with a good bit of silver or sea sand to keep it open. in order to make large specimens, they are shifted as soon as the pots are filled with roots. about the first week in june i place them out of doors on a border somewhat sheltered, and syringe the plants freely every day during hot weather to keep the foliage clean and healthy. i top them back till about seven or eight weeks before i want to show them, according to the requirements of the variety, as some of them require it to be done more freely than others. i give them liquid manure, using what i get from the cows, which with some soot is put into a tub, and allowed to stand a week or ten days before using, and i give them a good dose once a week as they show signs of flowering." in order to preserve his plants from the effects of hail and very heavy rains, a rough framework is erected, and over this is stretched some floral shading, which can be readily removed when required; it also serves the purpose of shading the plants from the sun in very hot and scorching weather. during his career as an exhibitor of fuchsias mr. lye has taken nearly one hundred first prizes--a measure of success which fully justifies the bestowal of the title of being the champion fuchsia grower of his day.--_r.d. in the gardeners' chronicle_. * * * * * a catalogue, containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . , stitched in paper, or $ . , bound in stiff covers. combined rates--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway, new york, n.y. * * * * * patents. in connection with the scientific american, messrs. munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats. trade marks, their costs, and how procured. address munn & co., broadway, new york. branch office, cor. f and th sts., washington, d.c. [illustration] scientific american (entered at the post office of new york, n. y., as second class matter) a weekly journal of practical information, art, science, mechanics, chemistry, and manufactures. new york, december , . vol. xliii., no. . [new series.] $ . per annum. [postage prepaid.] * * * * * contents. 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* table of contents of the scientific american supplement no. . for the week ending december , . price cents. for sale by all newsdealers. page i. engineering and mechanics.--frager's water meter. figures.-- vertical section, horizontal section, and plan transmission of power to a distance.--wire ropes--compressed air--water pressure.--electricity the livadia at sea the herreshoff launch new steering gear. figures.--steam steering gear for herreshoff launch ii. technology and chemistry.--glucose american manufacture of corn glucose the conversions--starch--dextrine.--complete glucose depreciation of a glucose factory the fire risks of glucose factories and manufactures glucose factory fires and ignitions the hirsh process. by adolf h. hirsh--improvement in the manufacture of sugar from corn time in the formation of salts. by m. berthelot an old can of preserved meat by g. w. wigner chemistry for amateurs. figures.--reaction between nitric acid and iron.--experiment with pharaoh's serpents.--formation of crystals of iodide of cyanogen--experiment with ammoniacal amalgam.--pyrophorus burning in contact with the air.--gold leaf suspended over mercury carbonic acid in the atmosphere. figures on potash fulling soaps by w. j. menzies photography of the invisible iii. electricity. light, heat, etc.--exhibition of gas and electric light apparatus, glasgow electric light in the german navy. illustration. armored frigates friedrich karl and sachsen.--dispatch boat grille, and torpedo boat illuminated by electric light interesting facts about gas and electricity.--gas as fuel.--gas for fire grates a new electric motor and its applications. figures. trouve's new electric motor on heat and light. by robert ward photophonic experiments of prof. bell and mr. tainter. by a. bregult distribution of light in the solar spectrum. by j. mace and w. nicati mounting microscopic objects new sun dial. by m. grootten. figure antoine cesar becquerel, with portrait iv. hygiene and medicine.--on the etiology of the carbuncular disease. by l. pasteur, assisted by chamberland and roux. an extremely valuable investigation of the nature, causes, and conditions of animal plagues report on yellow fever in the u. s. steamer plymouth. by the surgeon-general in u. s. navy fuchsin in bright's disease v. art, architecture, etc.--artists' homes. no. . sir frederick leighton's house and studio. figures. perspective, plan, elevation details, etc. initials by eisenlohr and weigle, in stuttgart. full page suggestions in decorative art. figure. reserved part of a great saloon. by h. penox, paris great saloon (text) cologne cathedral the historical procession suggestions in decorative art. figure. mantlepiece in walnut. by e. carpenter * * * * * one more number. the next issue will close another volume of this paper, and with it several thousand subscriptions will expire. it being an inflexible rule of the publishers to stop sending the paper when the time is up for which 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fires--causes and prevention. it is estimated that the total annual losses of insured property by fire, throughout the world, average nearly two hundred million dollars. add to this the annual destruction of uninsured property, and we should probably have a total amounting to quite double these figures. how great the loss, how severe the tax upon the productive industry of mankind, this enormous yearly destruction amounts to, will come home to the minds of most readers more directly if we call attention to the fact that it just about equals the value of our total wheat crop during a year of good yield. and it is a direct tax upon productive industry everywhere, because, although here and there a nominal loser, fully insured, has only made what is sometimes called "a good sale" to the companies holding his risk, this is only a way of apportioning the loss whereby the community at large become the sufferers. thus it is that we find all ably-managed insurance companies earnestly endeavoring to make it plain to the public how fires should be guarded against, or most effectually localized and controlled when once started. during the fall, or from "lighting up" time till about new year's day, more fires occur ordinarily than in any other portion of the year. this fact points to some of the most general causes of conflagrations--as in the lighting and heating of houses, factories, etc., where this had not been necessary during the summer months. it is also found that after the first of the year the number of fires is greatly diminished, the lighting and heating arrangements having been subjected to a period of trial during which their most obvious defects would be remedied. while it may readily be conceded that the utmost care of the owner of property could not totally prevent great average losses from fire--for the greater the holdings the more must the proprietor trust to the oversight of others--it is evident that the above facts indicate the necessity of more strenuous precautions at this season. gas pipes and fittings should then be tested; furnace flues and settings looked to; stove, heater, and grate fixtures and connections examined--and in all these particulars the scrutiny should be most closely directed to parts ordinarily covered up or out of sight, so that any defect or weakness from long disuse may be exposed. when to the above causes of fires we have added the extremely fruitful one found in the extensive use of coal oil within a few years past, we have indicated the most common sources of conflagrations of known origin. an english authority gives the percentages of different causes of , fires in london, from to , as follows: candles, . ; curtains, . ; flues, . ; gas, . ; sparks, . ; stoves, . ; children playing, . ; matches, . ; smoking tobacco, . , other known causes, . ; unknown causes, . . the foregoing figures do not give the percentage of incendiary fires, and later statistics would, no doubt, show vastly more fires from the use of kerosene than are here attributed to candles. the prevention of fires, and the best means of minimizing the loss when they do occur, are topics which cover a wide field, and a collection of the literature on the subject would make a very respectable library. as the question presents itself to-day, it may well be doubted whether the general practice of large property holders of insuring all their possessions does not tend to lessen the constant vigilance which is the most essential requisite in preventing fires. thousands of merchants never mean to keep a dollar's worth of goods in store or warehouse that is not fully covered by insurance, and they make this cost a regular charge upon their business as peremptorily as they do the wages paid the hands in their employ. but few manufacturers can so completely cover their risks by insurance, yet a large portion of them do so as far as they are able. it does not follow but that the larger portion of both merchants and manufacturers exercise what the law will fully decide is "due vigilance" in the care of the property so insured, but it is evident that in most cases the thoughtfulness is much less complete--the care wonderfully lacking in personal supervision--as compared with what would be the case were each one his own insurer. of course, this in no way casts a doubt upon the general policy of business men being amply insured, but in fact shows the greater necessity why they should be so, that they may not suffer from the carelessness of a neighbor; it also points to the necessity of continually increasing care and thoroughness of inspection on the part of the insurance companies. these agencies, in fact, must compel the insured to keep up to the mark in the introduction of every improvement to ward off fires or diminish their destructiveness. the progress made in this department during recent years has been great. the almost universal use of steam has been attended by the fitting up of factories with force pumps, hose, and all the appliances of a modern fire brigade; dangerous rooms are metal sheathed, and machinery likely to cause fire is surrounded by stationary pipes from which jets of water may be turned on instantaneously from the outside; stores and warehouses have standing pipes from which every floor may be flooded with water under pressure, and the elevators, those most dangerous flues for rapidly spreading a fire, are either bricked in entirely or supposed to be closed at every floor. the latter point, however, is sometimes forgotten, as sea captains forget to keep the divisions of their vessels having watertight compartments separate from one another; the open elevator enlarges a small fire as rapidly as the open compartment allows the vessel to sink. with the best of appliances, however, discipline and drill on the part of the hands, in all factories, is of prime importance. it is always in the first stages of a fire that thoroughly efficient action is necessary, and here it is worth a thousand-fold more than can be any efforts after a fire is once thoroughly started. long immunity is apt to beget a feeling of security, and the carelessness resulting from overconfidence has been the means of destroying many valuable factories which were amply provided with every facility for their own preservation. the teachers in some of the public schools of new york and brooklyn, during the past year, set an example which some of our millowners might profitably follow. there have been cases when, from a sudden alarm of fire, children have been crushed in their crowding to get out of the building. the teachers, in the instances referred to, marched their children out, under discipline, as if there had been a fire. let owners of factories try some such plan as this, by which workmen may be called upon to cope with an imaginary fire, and many of them will, we venture to say, find means of improving their present system or appliances for protection, elaborate as they may at present think them to be. * * * * * what is light? if on opening a text book on geology one should find stated the view concerning the creation and age of the earth that was held a hundred years ago, and this view gravely put forward as a possible or alternative hypothesis with the current one deducible from the nebula theory, one would be excused for smiling while he turned to the title page to see who in the name of geology should write such stuff. nevertheless this is precisely similar to what one will find in most treatises on physics for schools and colleges if he turns to the subject of light. for instance, i quote from a book edited by an eminent man of science in england, the book bearing the date . "there are two theories of light; one the _emissive_ theory; ... the other, the _vibratory_ theory;" just as if the emissive or corpuscular theory was not mathematically untenable sixty years ago, and experimentally demonstrated to be false more than forty years ago. unless one were treating of the history of the science of optics there is no reason why the latter theory should be mentioned any more than the old theory of the formation of the earth. it is not to be presumed that any one whose opinion is worth the asking still thinks it possible that the old view may be the true one because the evidence is demonstrable against it, yet while the undulatory theory prevails there are not a few persons well instructed otherwise who still write and speak as though light has some sort of independent existence as distinguished from so-called radiant heat; in other words, that the heat and light we receive from the sun are specifically different. a brief survey of our present knowledge of this form of energy will help to show how far wrong the common conception of light is. for fifteen years it has been common to hear heat spoken of as a mode of molecular motion, and sometimes it has been characterized as _vibratory_, and most persons have received the impression that the vibratory motion was an actual change of position of the molecular in space instead of a _change of form_. make a ring of wire five or six inches in diameter, and, holding it between the thumb and finger at the twisted ends, pluck it with a finger of the other hand; the ring will vibrate, have three nodes, and will give a good idea of the character of the vibration that constitutes what we call heat. this vibratory motion may have a greater or less amplitude, and the energy of the vibration will be as the square of that amplitude. but the vibrating molecule gives up its energy of vibration to the surrounding ether; that is to say, it loses amplitude precisely as a vibrating tuning fork will lose it. the ether transmits the energy it has received in every direction with the velocity of , miles per second, whether the amplitude be great or small, and whether the number of vibrations be many or few. it is quite immaterial. the _form_ of this energy which the ether transmits is _undulatory_; that is to say, not unlike that of the wave upon a loose rope when one end of it is shaken by the hand. as every shake of the hand starts a wave in the rope, so will every vibration of a part of the molecule start a wave in the ether. now we have several methods for measuring the wave lengths in ether, and we also know the velocity of movement. let v = velocity, l = wave length, and n = number of vibrations per second, then n = v/l, and by calculation the value of n varies within wide limits, say from Ã� ^{ } to Ã� ^{ }. but all vibrating bodies are capable of vibrating in several periods, the longest period being called the fundamental, and the remainder, which stand in some simple ratios to the fundamental, are called _harmonics_. each of these will give to the ether its own particular vibratory movement, so that a single molecule may be constantly giving out rays of many wave lengths precisely as a sounding bell gives out sounds of various pitches at one and the same time. again, when these undulations in the ether fall upon other molecules the latter may reflect them away or they may absorb them, in which case the absorbing molecules are themselves made to vibrate with increased amplitude, and we say they have been heated. some molecules, such as carbon, appear to be capable of stopping undulations of all wave lengths and to be heated by them; others are only affected by undulations of particular wave lengths, or of wave lengths between special limits. in this case it is a species of sympathetic vibration. the distinction between the molecular vibrations, and the undulations in ether that result from them, must be kept in mind, as must also the effect of the undulations that fall upon other molecules. to one the name _heat_ is applied, to the other the name of _radiant energy_ is given; and it matters not whether the undulations be long or short, the same molecule may give out both. now let a prism be placed in the path of such rays of different wave length from a single molecule, and what is called the dispersive action of the prism will separate the rays in the order of their wave lengths, the longer waves being less refracted than the shorter ones; but the energy of any one of these will depend upon the _amplitude of undulation_, which in turn will depend upon the amplitude of vibration of the part of the molecule that originated it, but in general the longer waves have greater amplitude, though not necessarily so. consequently, if a thermopile be so placed as to receive these various rays, and their energy be measured by its absorption on the face of the pile, each one would be found to heat it, the longer waves more than the shorter ones, simply because the amplitude is greater, but for no other reason, for it is possible, and in certain cases is the fact, that a short wave has as much or more energy than a longer one. if the eye should take the place of the thermopile it would be found that some of these rays did not affect it at all, while some would produce the sensation of light. this would be the case with any waves having a wave length between the limits of, say, - , of an inch and - , of an inch; any shorter waves will not produce the sensation of light. if instead of the eye a piece of paper washed in a solution of the chloride of silver should be placed where the dispersed rays should fall upon it, it would be found that only the shorter waves would affect it at all, and among these shorter ones would be some of those rays which the eye could not perceive at all. it was formerly inferred from these facts that the heat rays, the light rays, and the chemical rays were different in quality; and some of the late books treating upon this very subject represent a solar spectrum as being made up of a heat spectrum, a light spectrum, and an actinic or chemical spectrum, and the idea has often been made to do duty as an analogy in trinitarian theology; nevertheless it is utterly wrong and misleading. there is no such thing as an actinic spectrum; that is, there are no such rays as special chemical rays; any given ray will do chemical work if it falls upon the proper kind of matter. for instance, while it is true that for such salts of silver as the chloride, the bromide, etc., the shorter waves are most efficient; by employing salts of iron one may get photographic effects with wave lengths much too long for any eye to perceive. capt. abney has photographed the whole solar spectrum from one end to the other, which is sufficient evidence that there are no special chemical rays. as to the eye itself, certain of the wave lengths are competent to produce the sensation we call light, but the same ray will heat the face of a thermopile or produce photographic effects if permitted to act upon the proper material, so there is no more propriety in calling it a light ray than in calling it a heat ray or an actinic ray. what the ray will do depends solely upon what kind of matter it falls upon, and all three of these names, _light_, _heat_, and _actinism_, are names of _effects of radiant energy_. the retina of the eye is itself demonstrably a photographic plate having a substance called purpurine secreted by appropriate glands spread over it in place of the silver salts of common photography. this substance purpurine is rapidly decomposed by radiant energy of certain wave lengths, becoming bleached, but the decomposition is attended by certain molecular movements; the ends of the optic nerves, which are also spread over the retina, are shaken by the disrupting molecules, and the disturbance is the origin of what we call the sensation of light. but the sensation is generally a compound one, and when all wave lengths which are competent to affect the retina are present, the compound effect we call white or whiteness. when some of the rays are absent, as, for instance, the longer ones, the optical effect is one we call green or greenness; and the special physiological mechanism for producing the sensation may be either three special sets of nerves, capable of sympathetic vibration to waves of about - , , - , , and - , of an inch in length, as helmholtz has suggested, or, as seems to the writer more probable, the substance purpurine is a highly complex organic substance made up of molecules of different sizes and requiring wave lengths of different orders to decompose them, so that a part of the substance may be quite disintegrated, while other molecules may be quite entire throughout the visual space. this will account for most of the chromatic effects of vision, for complementary colors, and for color blindness, by supposing that the purpurine is not normally constituted. this is in accordance with experimental photography, for it has been found that the long waves will act only upon heavier molecules. it is true vision may be good when there is no purpurine, but there is no doubt but that this substance is secreted in the eye, and that it is photographic in its properties, and so far must be taken as an element in any theory of vision; but the chief point here considered is that objectively light does not exist independent of the eye, that light is a physiological phenomenon, and to speak of it otherwise is to confound a cause with an effect. it is, hence, incorrect to speak of the velocity of light; it has no velocity. it is _radiant energy_ that has the velocity of , miles a second. it is incorrect to say we receive heat from the sun. what we do receive is radiant energy, which is here transformed into heat. this is not hypercritical, but is in accordance with the knowledge we have to-day. the old nomenclature we use, but without definite meaning; the latter is left to be inferred from the connection or context. if a man should attach to the water main in a city a properly constructed waterwheel, the latter will rotate; but it would not be proper to say that he received rotation from the reservoir. what he received was water with a certain pressure; in other words, a certain form of energy, which he transforms into rotation by the appropriate means; but by substituting other means he can make the same water pressure maintain a vibratory motion, as with the hydraulic ram valve, or let it waste itself by open flow, in which case it becomes ultimately molecular vibration that is heat. the analogy holds strictly. the trouble all comes from neglecting to distinguish between different forms of energy--energy in matter and energy in the ether. * * * * * glass spinning and weaving. quite recently a pittsburg glass firm has succeeded, to a notable degree, in producing glass threads of sufficient fineness and elasticity to permit of their being woven into fabrics of novel character and quality. their success is such as to warrant the assumption that garments of pure glass, glistening and imperishable, are among the possibilities of the near future. the spinning of glass threads of extreme fineness is not a new process, but, as carried on at present by the firm in question--messrs. atterbury & co.--possesses considerable interest. from a quality of glass similar to that from which table ware is made, rods of glass averaging half an inch in diameter are drawn to any desired length and of various colors. these rods are then so placed that the flame of two gas burners is blown against that end of the rod pointed toward the large "spinning" wheel. the latter is / feet in diameter, and turns at the rate of revolutions per minute. the flames, having played upon the end of the glass cylinder until a melting heat is attained, a thread of glass is drawn from the rod and affixed to the periphery of the wheel, whose face is about inches wide. motion is then communicated, and the crystal thread is drawn from between the gas jets and wrapped upon the wheel at the rate of about , feet per minute. a higher speed results in a finer filament of glass, and vice versa. during its passage from the flame to the wheel, a distance of five or six feet, the thread has become cooled, and yet its elasticity is preserved to a notable degree. the next step in the process consists in the removal of the layers of threads from the wheel. this is easily accomplished, and after being cut to the desired lengths, the filaments are woven in a loom somewhat similar to that used in weaving silken goods. until within the past few weeks only the woof of the fabric was of glass, but at present both warp and woof are in crystal. samples of this cloth have been forwarded to new york and to chicago, and the manufacturers claim to be able to duplicate in colors, texture, etc., any garments sent them. a tablecloth of glass recently completed shines with a satiny, opalescent luster by day, and under gaslight shows remarkable beauty. imitation plumes, in opal, ruby, pale green, and other hues, are also constructed of these threads, and are wonderfully pretty. the chief obstacle yet to surmount seems to lie in the manipulation of these threads, which are so fine that a bunch containing is not so thick as an average sized knitting needle, and which do not possess the tractability of threads of silk or cotton. [the foregoing information is furnished by a correspondent in pittsburg. a sample of the goods mentioned, a tablecloth of glass, is now on exhibition in this city. the weaving of such heavy fabrics of glass for ornamental purposes and for curiosities is no new thing; nor, in our estimation, does comparative success in such experiments warrant the enthusiastic claims of the pittsburg manufacturers touching the adaptability of glass for wearing apparel. unless it is in their power to change the nature of glass absolutely and radically, it does not seem possible for them so to overcome the ultimate brittleness of the separate fibers as to make the fabric fit to be brought in contact with the skin. the woven stuff may be relatively tough and flexible; but unless the entire fabric can be made of one unbreakable fiber the touch of the free ends, be they never so fine, must be anything but pleasant or beneficial, if one can judge by the finest filaments of glass spun hitherto. besides, in weaving and wearing the goods, a certain amount of fiber dust must be produced as in the case of all other textile material. when the softest of vegetable fibers are employed the air charged with their fragments is hurtful to the lungs; still more injurious must be the spiculæ of spun glass. however, although the manufacturers are likely to be disappointed in their expectation of finding in glass a cheap and available substitute for linen, cotton, and silk in dress goods, it is quite possible that a wide range of useful application may be found for their new fabric.] * * * * * remarkable eruption of mauna loa. late advices from the sandwich islands describe the eruption of mauna loa, which began nov. , as one of the grandest ever witnessed. the opening was about six miles from the summit of the mountain, and already two great streams of lava had been poured out; one of them, from one to two yards wide and twenty feet deep, had reached a distance of thirty miles. terrible explosions accompany the flow of the lava stream, which for a time threatened the town of hilo; at last reports the flow seemed to be turning in another direction. mauna loa, "long or high mountain" occupies a large portion of the central and southern part of the island of hawaii, and reaches an elevation of , feet. it has been built up by lavas thrown out in a highly fluid state, and flowing long distances before cooling; as a consequence the slopes of the mountain are very gentle, averaging, according to prof. dana, not more than six and a half degrees. its craters are numerous, and usually occur near the summit and on the sides, new ones opening frequently, and furnishing, as in the latest instance, magnificent lava streams. the terminal crater is circular, , feet in diameter, and in was about , feet deep. in an enormous lava fountain spouted from this crater for four or five days, throwing a column of white hot fluid lava about feet in diameter to the height of two or three hundred feet. the lava stream ran miles to the sea in eight days. other great eruptions have occurred in , , , , , and . the lava streams poured out in , , and , flowed to the sea, adding considerably to the area of the island. those of and are estimated to have poured out respectively , , , and , , , cubic feet of lava. in the lava stream forced its way under ground a distance of twenty miles, and burst forth from a fissure two miles long, throwing up enormous columns of crimson lava and red hot rock to the height of five or six hundred feet. on the eastern part of mauna loa, miles from the summit crater, is kilauea, the largest continuously active crater in the world. it is eight miles in circumference, and , feet deep. its eruptions are generally independent of those of mauna loa. * * * * * new air engine. a valuable improvement in compressed air engines has recently been patented in this country and in europe by col. f. e. b. beaumont, of the royal engineers, and we learn from accounts given in the london and provincial papers that it has proved highly efficient and satisfactory. the engine possesses some peculiar features which render it very economical in the use of compressed air. it has two cylinders, one being much larger than the other. into the smaller of these cylinders the compressed air is taken directly from the reservoir, and after doing its work there it is discharged into the larger cylinder, where it is further expanded, being finally discharged into the open air. the admission of air to the smaller cylinder is regulated by an adjustable cut-off apparatus, which admits of maintaining a uniform power under a variable pressure. when the reservoir at first starting contains air at a very high pressure, the cut-off is adjusted so that the small cylinder receives a very small charge of air at each stroke; when the pressure in the reservoir diminishes the cut-off is delayed so that a larger quantity of air is admitted to the small cylinder; and when the pressure in the reservoir is so far reduced that the pressure on the smaller piston gives very little power, the supply passages are kept open so that the air acts directly on the piston of the larger cylinder. this arrangement is also available when the air pressure is high and great power is required for a short time, as, for example, in starting a locomotive. it is, perhaps, needless to mention the advantages a motor of this kind possesses over the steam locomotive. the absence of smoke and noise renders it particularly desirable for tunnels, elevated roads, and, in fact, for any city railroad. further information in regard to this important invention may be obtained by addressing mr. r. ten broeck, at the windsor hotel, new york. * * * * * telegraph wires underground. philadelphia newspapers report that the american union telegraph company are about to try in that city the experiment of putting their wires underground. the plan works well enough in european cities, and there would seem to be no reason why it should not succeed here, save the indisposition of the companies to bear the first cost of making the change. for some months the western union telegraph company has had the matter under consideration, but will probably wait until pressed by a rival company before it undertakes the more serious task of taking down its forest of poles and sinking the wires which contribute so much to the prevailing ugliness of our streets. sooner or later the poles and wires must come down; and it is altogether probable that the change will be beneficial to the companies in the long run, owing to the smaller cost of maintaining a subterranean system. it will certainly be an advantage to the community. * * * * * improved safety nut. that a safety nut so simple and so obviously efficient as the one shown in the annexed engraving should be among the recent inventions in this line instead of being among the first, is a curious example of the manner in which inventors often overlook the simplest means of accomplishing an end. the principle on which this nut operates will be understood by reference to the engraving. two nuts are represented on each bolt, simply for the purpose of showing the difference between the nut when loose and when screwed down. in practice only one nut is required to each bolt. the square nut shown in fig. is concaved on its under side, so that it touches its bearings only at the corners and in the outer face of the nut there are two slots at right angles to each other. when this nut is screwed home the outer portion is contracted so as to clamp the bolt tightly. the hexagonal nut shown in fig. has but a single transverse slot, and the nut is made concave on the under surface, so that when the nut is screwed home it will contract the outer portion and so clamp the bolt. this nut may be removed and replaced by means of the wrench, but it will not become accidentally loosened, and the bolt to which it is applied will always remain tight, as the nut possesses a certain amount of elasticity. the action of this nut is such as to prevent stripping the threads of either bolt or nut. as only one nut is used with each bolt, and as no washer or other extra appliance is required, it is obvious that a great saving is effected by this invention. we are informed that several of the leading railroads have adopted this nut, and use it on the tracks, engines, cars, and machinery. the atwood safety nut company manufacture this article in a variety of forms. [illustration: the atwood safety nut.] further information may be obtained by addressing j. w. labaree, secretary and treasurer, room , agawam bank building, springfield, mass. * * * * * petroleum prospects. the total oil production of the pennsylvania oil regions for the month of october was , , barrels. the conditions in the producing field are gradually giving warrant for permanently higher prices of crude. the confidence of the trade is daily becoming more fixed in the definiteness and limit of the bradford field, as the last of the several "rich streaks" in the region are being worked. we entertain an increased belief that the coming year will exhibit a continued falling off in the volume of production, notwithstanding all the modern improvements in drilling and the great energy with which they are employed. for the past few weeks the markets of both crude and refined seem to have been rigorously and artificially held by the refining interest. the refined has been quoted at cts. for four weeks without change--and as a consequence the exporter has taken oil very sparingly. the exports of last year to november , as compared with the exports of this year to november , show a decrease of , , barrels in crude equivalent. the falling off of production, taken together with the increased demand which must result from the present reluctance of exporters, unite in warranting us in the belief above expressed, in enhanced prices for the coming year. our figures show a decrease in production for last month, compared with the preceding month, of barrels per day, notwithstanding the number of wells drilled was slightly greater than in the preceding month. it will be noticed, too, that the average per well of the new wells for last month is a little less than that of the new wells for the month before, besides, it is generally recognized that the force of the gas in the region is gradually becoming less, and pumping is more commonly resorted to. as nearly as we can ascertain, about one-eighth of all the wheels of the bradford region are now pumping. we believe, however, on the whole, judging the character of the bradford producing field, that the falling off of production will be quite gradual. our reason for this is that the bradford field is essentially different from its predecessor--the butler field. the wells in the butler field were often close together, many of them were very large and fell off rapidly; while the wells of the bradford region are smaller, farther apart, much greater in number, have a greater area from which to draw oil, and consequently decline very much more slowly.--_stowell's reporter_. * * * * * tool for driving and clinching nails. a novel method of making a nail hole and driving and clinching the nail is shown in the annexed engraving. the instrument for making the hole has a notched end which leaves a ridge in the center of the hole at the bottom. the nail driving tool consists of a socket provided with a suitable handle, and containing a follower which rests upon the head of the nail to be driven, and receives the blows of the hammer in the operation of driving the nail. the nail is split for one half its length, and the two arms thus formed are slightly separated at the point, so that when they meet the ridge at the bottom of the hole they will be still further separated and will clinch in the body of the wood. [illustration: tool for driving and clinching nails.] this invention was recently patented by mr. charles p. ball, of danville, ky. * * * * * automatic balance attachment for valves. it is well known that in all air compressors and water pumps the pressure in cylinder of air compressors or in working barrel or cylinder of pumps is much greater at the point of opening the delivery valves than the actual pressure in the air receivers of compressors or in water column of pumps because of the difference in area between the top and bottom of delivery valves. in some air compressors a hundred and twenty-five pounds pressure to the square inch is required in the cylinder to eighty pounds in the receiver, and in some instances a hundred pounds pressure is required in the cylinder to eighty pounds pressure in the receiver or column. the engraving shows an invention designed to remedy this defect in air compressors and pumps, to provide a device which will enable the compressors and pumps to operate with equal pressure on both sides of the delivery valve. the invention consists of an auxiliary valve arranged outside of the cylinder, where it is not subjected to back pressure, and connected with the delivery valve by a hollow valve stem. in the engraving, which is a sectional view, the cylinder of an air compressor is represented, on the end of which there is a ring containing delivery ports, through which the air from the cylinder is forced into a receiver or conducting pipe. this ring is provided with an inner flange or valve seat on which rests the delivery valve. these parts are similar to those seen in some of the air compressors in common use, and with this construction and arrangement one hundred pounds pressure to the square inch in the cylinder is required to open the valve against eighty pounds pressure in the receiver or in the conducting pipes. [illustration: automatic balance attachment for delivery valves of air compressors and water pumps.] a drum having an open end is connected with the cylinder head by inclined standards, and contains a piston connected with the valve by means of a rod that extends centrally through the cylinder head. on the outer end of this rod is screwed an adjusting nut, by means of which the piston may be adjusted. this rod is bored longitudinally, establishing communication between the compressor cylinder and the drum containing the piston. it will be seen that the upper face of the piston is exposed so as to be subjected to atmospheric pressure only, and when the compressor is in operation a portion of the air in the compressor cylinder passes through the hollow rod into the space beneath the piston, and there exerts sufficient pressure, in combination with the pressure on the inner face of the valve, to open the valve against an equal pressure in the receiver or conducting pipes, so that when the pressure in the cylinder equals the pressure in the receivers the valve is opened and held in place until the piston in the cylinder starts on the return stroke, when the pressure under the piston is immediately relieved through the hollow rod and the main valve closes. the space between the valve and its seat is made as shallow as possible, so that the space may be quickly filled and exhausted. the piston may be adjusted to regulate this space. this invention was recently patented by messrs. samuel b. connor and henry dods, of virginia city, nevada. * * * * * improved safety valve. in the annexed cut we have represented a steam safety valve, which is the invention of m. schmidt, m. e., of zurich, switzerland. it consists of a lever terminating in two prongs, one of which extends downward and rests upon the cap, closing the top of the tube through which the steam escapes. the other prong extends upward and catches under a projection of the steam tube, and forms the fulcrum for the lever. the opposite end of this lever is provided with an adjustable screw pressing upon a plate that rests on the top of a spiral spring, which keeps the valve closed by pressing the outer end of the lever upward. as soon as the pressure of the steam overcomes the pressure of the spiral spring the valve will be raised, permitting the steam to escape. the apparatus is contained in a case having a central aperture for the escape of steam. [illustration: improved safety valve.] * * * * * raising sunken vessels. an experiment recently took place in the east india dock basin, blackwall, london, by permission of mr. j. l. du plat taylor, the secretary of the dock company, for the purpose of testing and illustrating the mode of raising sunken ships by means of the apparatus patented by mr. william atkinson, naval engineer, of sheffield. the machinery employed consists of the necessary number and size, according to the power required, of oval or egg-shaped buoys constructed of sheet iron, having an internal valve of a simple and effective character. captain hales dutton, the dock master, who assisted during the operations, had placed his small yacht at the inventor's service for the occasion. the vessel was moored in the basin, and a set of four buoys were attached to it, one on each side near the bow and the stern. air was supplied from a pump on the quay by a pipe communicating with a small copper globe resting on the deck of the vessel, and from which place proceeded four other flexible tubes, one to each buoy, thus distributing the air to each one equally. the vessel being flooded and in a sinking condition, the buoys were attached and the valves opened; they rapidly filled with water, and the vessel immediately sank in about feet. upon the first attempt an air chamber in the stern had been lost sight of, causing the vessel to come up to the surface stern uppermost; this being rectified, the vessel was again sent to the bottom, and allowed to remain a short time to allow her to settle down. when the order was given to work the pump, the vessel was brought to the surface, perfectly level, in about three minutes. the apparatus used, although only models, and on a comparatively diminutive scale (the buoys measuring feet inches in height and feet inches in diameter), was estimated to be capable of lifting a weight of nearly tons, and that it needed, as represented by the patentee, only a corresponding increase in the lifting power to deal successfully with vessels of any tonnage. * * * * * new hand power band saw. the engraving shows a new hand power band saw made by frank & co., of buffalo, n. y., and designed to be used in shops where there is no power and where a larger machine would be useless. it is calculated to meet the wants of a large class of mechanics, including carpenters and builders, cabinet makers, and wagon makers. it is capable of sawing stuff six inches thick, and has a clear space of thirty inches between the saw and the frame. the upper wheel is adjusted by a screw pressing against a rubber spring which compensates for the expansion and contraction of the saw. the machine has a very complete device for raising, lowering, and adjusting the wheel, and all of the parts are made with a view to obtaining the best results in the simplest and most desirable way. the machine is six feet wide and five feet high, and weighs lb. the wheels are covered with pure rubber bands well cemented. [illustration: hand power band saw.] further particulars may be obtained by addressing messrs. frank & co., terrace street, buffalo, n. y. * * * * * the harbor of montreal. a plan for the improvement of the harbor of montreal, canada, has been submitted to the city board of trade by james shearer, a well known citizen. mr. shearer's plan is to divert the current of the st. lawrence opposite the city into the channels between st. helen's island and the southern shore, and by having various obstructions removed from the channel, and running a dam, or "peninsula," as he calls it, built from point st. charles, in the west end of the city, to st. helen's island, midway in the river, thus stopping the current from running through the present main channel between the city and st. helen's island. among the practical advantages that will accrue to the city and harbor from the carrying out of this project, mr. shearer sets forth the following: the dam will prevent the shoring of ice opposite the city, and the consequent flooding of the griffintown district, which is annually very destructive to property, and will make a still harbor, where vessels may lie during the winter. it is estimated that the construction of the dam, which would be , feet long and feet broad, would raise the water two feet in the river and lower it ten feet in the harbor. this would give a head of twenty-five feet for mills, elevators, and factories, and the transportation of freight. the dam would afford a roadway across the river, upon the construction of a bridge from st. helen's island to st. lambert, thus removing the necessity of a tunnel. the roadway could be utilized for a railway, a road for carriages and foot passengers. the estimated cost of the improvement is $ , , . * * * * * apparatus for removing ice from railroads. the engraving shows an improved apparatus for removing snow and ice from railroads and streets by means of heat. the invention consists of a double furnace mounted on wheels, which are incased in the fire boxes of the furnace, so that in use the entire apparatus, including the wheels, will become highly heated, so that the snow and ice will not only be melted by radiant heat, but by the actual contact of the hot surfaces of the furnace and wheels. this apparatus was recently patented by the late e. h. angamar, of new orleans, la. [illustration: apparatus for removing ice from railroads.] * * * * * ericsson's new submarine gun. the protracted trials conducted on board the destroyer to test its submarine gun terminated last week. having, says the _army and navy journal_, in a previous issue described this novel type of naval artillery, it will suffice to remind our readers that its caliber is inches, length of bore feet, and that it is placed at the bottom of the vessel, the muzzle passing through an opening formed in the wrought iron stem. we have hitherto, in discussing the properties of the destroyer, referred to its offensive weapon as a "torpedo," a term not altogether inappropriate while it was actuated by compressed air. but capt. ericsson having in the meantime wholly abolished compressed air in his new system of naval attack, substituting guns and gunpowder as the means of producing motive energy, it will be proper to adopt the constructor's term, _projectile_. it will not surprise those who are acquainted with the laws of hydrostatics and the enormous resistance offered to bodies moving swiftly through water, that the determination of the proper form of projectile for the submarine gun has demanded protracted experiments, commencing at the beginning of june and continued up to last week, as before stated. the greater portion of these experiments, it should be observed, has been carried out with a gun feet long, inches caliber--not a breech-loader, however, as in the destroyer, but a muzzle-loader, suspended under the bottom of two wrecking scows, the gun being lifted above the water, after each shot, by shears and suitable tackle. the present projectile of the destroyer is the result of the extended trials referred to; its length is feet inches, diameter inches, and its weight , pounds, including pounds of explosive materials. we are not at liberty at present to describe its form, but we may mention that the great length of the body and the absence of all internal machinery enable the constructor to carry the stated enormous quantity of explosive matter. with minimum charge of powder in the chamber of the gun, the speed attained by the projectile reaches feet in the first three seconds. the question may be asked, in view of these facts, whether the boasted costly steam ram is not superseded by the cheap aggressive system represented by the destroyer. evidently the most powerful of the english steam rams could not destroy an armored ship as effectually as the projectile from the submarine gun, the explosion of which is capable of shattering any naval structure. it should be borne in mind, also, that being protected by heavy inclined transverse armor, the destroyer, attacking bows on, can defy ordnance of all calibers. again, the carrier of the submarine gun, in addition to the swiftness of its projectile, can outrun ironclad ships. * * * * * recent inventions. mr. francis m. osborn, of port chester, n. y., has patented a covering for a horse that protects him from the weather and from chafing. the blanket has a band, also stays and straps, the use of which does away with the surcingle and affords a most efficient protection for the horse, and may be easily worn under harness in wet weather or at other times, when desirable. a novel device, designed especially for containing boxes of cigars and protecting and displaying their contents, has been patented by mr. robert b. dando, of alta, iowa. the invention consists of a case containing shelves, on which are fixed the covered cigar or other boxes, cords connecting the box lids and case doors, so that the opening of the case doors causes the box lids to open. an improved bottle stopper has been patented by mr. andrew walker, of cincinnati, o. the invention consists in combining with the stopper caps connected by an intermediate spring. mr. james b. law, of darlington court house, s. c., has patented an improved construction of buckle for fastening the ends of cotton and other bale bands; it consists in a buckle having a permanent seat for one end of the bale band, a central opening, into which the other end of the band is entered through an oblique channel, and a bar offsetting from the plane of the buckle, notched or recessed to prevent lateral movement of the band, and connecting the free ends of the buckle on each side of the oblique channel to strengthen the buckle. an improved buckboard wagon has been patented by mr. william sanford, of cohoes, n. y. the invention consists in combining with the buckboards curved longitudinal springs placed beneath the buckboards, and curved cross springs connected at their ends with the buckboards by cap plates so as to increase the strength and elasticity of the wagon. an improved vehicle wheel has been patented by messrs. george w. dudley and william j. jones, of waynesborough, va. the main object of this invention is to form a wheel hub for vehicles in such manner that the wheel will yield sufficiently when undue and sudden strains or jars may come upon it to receive the force of the blow and shield the other portions of the vehicle from the destructive effects of such action, as well as to afford ease and comfort of motion to the occupant; and the improvement consists in securing the inner ends of the spokes to rim plates, to form a fixed and solid connection therewith, the rim plates being loosely secured to the butt flanges and box of the hub, so that it is free to move in a vertical plane, but prevented from moving laterally and limited in its vertical movement by an elastic packing interposed between the inner ends of the spokes and the hub box. mr. francis g. powers, of moweaqua, ill., has patented an improvement in the class of atmospheric clothes pounders, that is to say, pounders which are constructed with one or more chambers or cavities in which the air is alternately compressed and allowed to expand at each reciprocation. an improved means for connecting the body of a baby carriage to the running gear has been patented by mr. charles m. hubbard, of columbus, ohio. it consists in supporting the rear end by one or more coil springs, and hinging the front portion of the body to a pair of upturned supports rising from the front axle. an improved ferrule for awl handles has been patented by mr. jules steinmeyer, of st. louis, mo. the object of this invention is to prevent splitting of the handle, to secure both the ferrule and leather pad firmly in place, and to furnish a durable and serviceable awl handle. * * * * * new telegraph insulator. the insulator represented in the annexed engraving was originally designed to meet the requirements of south american telegraph service, but it is equally well adapted to lines in other places. the main idea is to avoid breakage from expansion and contraction in a climate subject to sudden changes of temperature, and to avoid the mischief occasioned by a well known south american bird, the "hornero," by building nests of mud on the brackets and insulators. with this insulator these nests cannot cause a weather contact or earth; on the contrary, the nest rather improves the insulation. the sectional view, fig , shows the construction of the insulator and the manner of fastening it to the cross arm or bracket. a rubber ring is placed between the upper end of the porcelain insulator and the cross arm, and another similar ring is placed between the head of the suspending screw and the bottom of the insulator. it will be noticed that with this construction the insulator cannot be broken by the contraction of the screw or by the swelling of the cross-piece. this insulator can be used on an iron bracket and in connection with either iron or wooden posts, and is in every way more secure than the insulators in common use. the first cost of these insulators compares favorably with the cheapest in market, while it is less liable to breakage, lasts longer, and gives better results. it has been patented in this country and in europe. [illustration: improved telegraph insulator.] further information maybe obtained by addressing mr. j. h. bloomfield, concordia, entre reos, argentine republic, south america. * * * * * business colleges. packard's business college. [illustration: the first department] [illustration: second department] [illustration: third department] [illustration: fourth or finishing department] [illustration: the budget room] [illustration: the assembly room] there are two very general prejudices against the class of schools known as business colleges. one is that their chief aim--next to lining the pockets of their proprietors--is to turn out candidates for petty clerkships, when the country is already overrun with young men whose main ambition is to stand at a desk and "keep books." the other is that the practical outcome of these institutions is a swarm of conceited flourishers with the pen, who, because they have copied a set or two of model account books and learned to imitate more or less cleverly certain illegibly artistic writing copies, imagine themselves competent for any business post, and worthy of a much higher salary than any merely practical accountant who has never been to a business college or attempted the art of fancy penmanship as exhibited in spread eagles and impossible swans. as a rule popular prejudices are not wholly unfounded in reason; and we should not feel disposed to make an exception in this case. when the demand arose for a more practical schooling than the old fashioned schools afforded, no end of writing masters, utterly ignorant of actual business life and methods, hastened to set up ill managed writing schools which they dubbed "business colleges," and by dint of advertising succeeded in calling in a multitude of aspirants for clerkships. in view of the speedy discomfiture of the deluded graduates of such schools when brought face to face with actual business affairs, and the disgust of their employers who had engaged them on the strength of their alleged business training, one is not so much surprised that prejudice against business colleges still prevails in many quarters, as that the relatively few genuine institutions should have been able to gain any creditable footing at all. the single fact that they have overcome the opprobrium cast upon their name by quacks, so far as to maintain themselves in useful prosperity, winning a permanent and honorable place among the progressive educational institutions of the day, is proof enough that they have a mission to fulfill and are fulfilling it. this, however, is not simply, as many suppose, in training young men and young women to be skilled accountants--a calling of no mean scope and importance in itself--but more particularly in furnishing young people, destined for all sorts of callings, with that practical knowledge of business affairs which every man or woman of means has constant need of in every-day life. thus the true business college performs a twofold function. as a technical school it trains its students for a specific occupation, that of the accountant; at the same time it supplements the education not only of the intending merchant, but equally of the mechanic, the man of leisure, the manufacturer, the farmer, the professional man--in short, of any one who expects to mix with or play any considerable part in the affairs of men. the mechanic who aspires to be the master of a successful shop of his own, or foreman or manager in the factory of another, will have constant need of the business habits and the knowledge of business methods and operations which a properly conducted business school will give him. the same is true of the manufacturer, whose complicated, and it may be extensive, business relations with the producers and dealers who supply him with raw material, with the workmen who convert such material into finished wares, with the merchants or agents who market the products of his factory, all require his oversight and direction. indeed, whoever aspires to something better than a hand-to-mouth struggle with poverty, whether as mechanic, farmer, professional man, or what not, must of necessity be to some degree a business man; and in every position in life business training and a practical knowledge of financial affairs are potent factors in securing success. how different, for example, would have been the history of our great inventors had they all possessed that knowledge of business affairs which would have enabled them to put their inventions in a business like way before the world, or before the capitalists whose assistance they wished to invoke. the history of invention is full of illustrations of men who have starved with valuable patents standing in their names--patents which have proved the basis of large fortunes to those who were competent to develop the wealth that was in them. how often, too, do we see capable and ingenious and skillful mechanics confined through life to a small shop, or to a subordinate position in a large shop, solely through their inability to manage the affairs of a larger business. on the other hand, it is no uncommon thing to see what might be a profitable business--which has been fairly thrust upon a lucky inventor or manufacturer by the urgency of popular needs--fail disastrously through ignorance of business methods and inability to conduct properly the larger affairs which fell to the owner's hand. of course a business training is not the only condition of success in life. many have it and fail; others begin without it and succeed, gaining a working knowledge of business affairs through the exigencies of their own increasing business needs. nevertheless, in whatever line in life a man's course may fall, a practical business training will be no hinderance to him, while the lack of it may be a serious hinderance. the school of experience is by no means to be despised. to many it is the only school available. but unhappily its teachings are apt to come too late, and often they are fatally expensive. whoever can attain the needed knowledge in a quicker and cheaper way will obviously do well so to obtain it; and the supplying of such practical knowledge, and the training which may largely take the place of experience in actual business, is the proper function of the true business college. our purpose in this writing, however, was not so much to enlarge upon the utility of business colleges, properly so called, as to describe the practical working of a representative institution, choosing for the purpose packard's business college in this city. this school was established in , under the name of bryant, stratton & packard's mercantile college, by mr. s. s. packard, the present proprietor. it formed the new york link in the chain of institutions known as the bryant & stratton chain of business colleges, which ultimately embraced fifty co working schools in the principal cities of the united states and canada. in mr. packard purchased the bryant & stratton interest in the new york college, and changed its name to packard's business college, retaining the good will and all the co operative advantages of the bryant & stratton association. the original purpose of the college, as its name implies, was the education of young men for business pursuits. the experience of over twenty years has led to many improvements in the working of the school, and to a considerable enlargement of its scope and constituency, which now includes adults as well as boys, especial opportunities being offered to mature men who want particular instruction in arithmetic, bookkeeping, penmanship, correspondence, and the like. [illustration: lecture and recitation room.] the teachers employed in the college are chosen for their practical as well as their theoretical knowledge of business affairs, and every effort is made to secure timeliness and accuracy in their teachings. constant intercourse is kept up with the departments at washington as to facts and changes in financial matters, and also with prominent business houses in this and other cities. among the recent letters received in correspondence of this sort are letters from the secretary of state of every state in the union with regard to rates of interest and usury laws, and letters from each of our city banks as to methods of reckoning time on paper, the basis of interest calculations, the practices concerning deposit balances, and other business matters subject to change. the aim of the proprietor is to keep the school abreast of the demands of the business world, and to omit nothing, either in his methods or their enforcement, necessary to carry out his purpose honestly and completely. an idea of the superior housing of the college will be obtained from the views of half a dozen of the rooms at no broadway, as shown in this issue of the scientific american--the finest, largest, most compact, and convenient suite of rooms anywhere used for this purpose. the college is open for students ten months of the year, five days each week, from half past nine in the morning until half past two in the afternoon. students can enter at any time with equal advantage, the instruction being for the most part individual. the course of study can be completed in about a year. the proprietor holds that with this amount of study a boy of seventeen should be able-- . to take a position as assistant bookkeeper in almost any kind of business; . to do the ordinary correspondence of a business house, so far as good writing, correct spelling, grammatical construction, and mechanical requisites are concerned; . to do the work of an entry clerk or cashier; . to place himself in the direct line of promotion to any desirable place in business or life, with the certainty of holding his own at every step. in this the student will have the advantage over the uneducated clerk of the same age and equal worth and capacity, in that he will understand more or less practically as well as theoretically the duties of those above him, and will thus be able to advance to more responsible positions as rapidly as his years and maturity may justify. it is obvious that the knowledge which makes an expert accountant will in all probability suffice for the general business requirements of professional men, the inheritors of property and business, manufacturers, mechanics, and others to whom bookkeeping and other business arts are useful aids, but not the basis of a trade. for the last-named classes, and for women, shorter periods of study are provided, and may be made productive of good results. a sufficient idea of the general working of the college may be obtained by following a student through the several departments. after the preliminary examination a student who is to take the regular course of study enters the initiatory room. here he begins with the rudiments of bookkeeping, the study which marks his gradation. the time not given to the practice of writing, and to recitations in other subjects, is devoted to the study of accounts. he is required, first, to write up in "skeleton" form--that is, to place the dates and amounts of the several transactions under the proper ledger titles--six separate sets of books, or the record of six different business ventures, wherein are exhibited as great a variety of operations as possible, with varying results of gains and losses, and the adjustment thereof in the partners' accounts, or in the account of the sole proprietor. after getting the results in this informal way--which is done in order as quickly as possible to get the theory of bookkeeping impressed upon his mind--he is required to go over the work again carefully, writing up with neatness and precision all the principal and auxiliary books, with the documents which should accompany the transactions, such as notes, drafts, checks, receipts, invoices, letters, etc. the work in this department will occupy an industrious and intelligent student from four to six weeks, depending upon his quickness of perception and his working qualities. while progressing in his bookkeeping, he is pursuing the collateral studies, a certain attainment in which is essential to promotion, especially correcting any marked deficiency in spelling, arithmetic, and the use of language. upon a satisfactory examination the student now passes to the second department, where a wider scope of knowledge in accounts is opened to him, with a large amount of practical detail familiarizing him with the actual operations of business. the greatest care is taken to prevent mere copying and to throw the student upon his own resources, by obliging him to correct his own blunders, and to work out his own results; accepting nothing as final that has not the characteristics of real business. much care is bestowed in this department upon the form and essential matter of business paper, and especially of correspondence. a great variety of letters is required to be written on assigned topics and in connection with the business which is recorded, and thorough instruction is given in the law of negotiable paper, contracts, etc. during all this time the student devotes from half an hour to an hour daily to penmanship, a plain, practical, legible hand being aimed at, to the exclusion of superfluous lines and flourishes. it is expected that the work in the first and second departments will establish the student in the main principles of bookkeeping, in its general theories, and their application to ordinary transactions. in the third department the student takes an advanced position, and is expected, during the two or three months he will remain in this department, to perfect himself in the more subtle questions involved in accounts, as well as to shake off the crude belongings of schoolboy work. he will be required to use his mind in everything he does--to depend as much as possible upon himself. the work which he presents for approval here must have the characteristics of business. his letters, statements, and papers of all kinds are critically examined, and approved only when giving evidence of conscientious work, as well as coming up to strict business requirements. before he leaves this department he should be versed in all the theories of accounts, should write an acceptable business hand; should be able to execute a faultless letter so far as relates to form, spelling, and grammatical construction, should have a fair knowledge of commercial law, and have completed his arithmetical course. the next step is to reduce the student's theoretical knowledge to practice, in a department devoted to actual business operations. this business or finishing department is shown at the upper left corner of our front page illustration. the work in this department is as exacting and as real as the work in the best business houses and banks. at the extreme end of the room is a bank in complete operation, as perfect in its functions as any bank in this city or elsewhere. the records made in its books come from the real transactions of dealers who are engaged in different lines of business at their desks and in the offices. the small office adjoining the bank, on the right, is a post office, the only one in the country, perhaps, where true civil service rules are strictly observed. in connection with it is a transportation office. from fifty to a hundred letters daily are received and delivered by the post office, written by or to the students of this department. the correspondence thus indicated goes on not only between the students of this college, but between members of this and other similar institutions in different parts of the country. a perfected system of intercommunication has for years been in practice between co-ordinate schools in new york, boston, brooklyn, philadelphia, chicago, baltimore, and other cities, by which is carried on an elaborate scheme of interchangeable business, little less real in its operations and results than the more tangible and obtrusive activity which the world recognizes as business. the work of the transportation office corresponds with that of the post office in its simulation of reality. the alleged articles handled are represented by packages bearing all the characteristic marks of freight and express packages. they are sent by mail to the transportation company, and by this agency delivered to the proper parties, from whom the charges are collected in due form, and the requisite vouchers passed. whatever is necessary in the way of manipulation to secure the record on either hand is done, and, so far as the clerical duties are concerned, there is no difference between handling pieces of paper which represent merchandise and handling the real article. in the bank is employed a regular working force, such as may be found in any bank, consisting of a collector or runner, a discount clerk, a deposit bookkeeper, a general bookkeeper, and a cashier. the books are of the regular form, and the work is divided as in most banks of medium size, and the business that is presented differs in no important particular from that which comes to ordinary banks. after getting a fair knowledge of theory, the student is placed in this bank. he begins in the lowest place, and works up gradually to the highest, remaining long enough in each position to acquaint himself with its duties. he is made familiar with the form and purpose of all kinds of business paper, and the rules which govern a bank's dealings with its customers. he gets a practical knowledge of the law of indorsement and of negotiability generally, and is called upon to decide important questions which arise between the bank and its dealers. wherever he finds himself at fault he has access to a teacher whose duty it is to give the information for which he asks, and who is competent to do it. throughout the whole of this course of study and practice the students are treated like men and are expected to behave like men. the college thus becomes a self-regulating community, in which the students learn not only to govern themselves, but to direct and control others. as one is advanced in position his responsibilities are increased. he is first a merchant or agent, directing his own work; next, a sub-manager, and finally manager in a general office or the bank, with clerks subject to his direction and criticism, until he arrives at the exalted position of "superintendent of offices," which gives him virtual control of the department. this is, in fact, an important part of his training, and the reasonable effect of the system is that the student, being subject to orders from those above him, and remembering that he will shortly require a like consideration from those below him, concludes that he cannot do a better thing for his own future comfort than to set a wholesome example of subordination. this, however, is not the only element of personal discipline that the college affords. at every step the student's conduct, character, and progress are noted, recorded, and securely kept for the teacher's inspection, as well as that of his parents and himself. such records are kept in the budget room, shown in the lower left corner of the front page. this budget system was suggested by the difficulties encountered in explaining to parents the progress and standing of their sons. the inconvenience of summoning teachers, and of taking students from their work, made necessary some simpler and more effective plan. the first thing required of a new student is that he should give some account of himself, and to submit to such examinations and tests as will acquaint his teachers with his status. this account and these tests constitute the subject-matter of his first budget, which is placed at the bottom of his box, and every four weeks thereafter, while he remains in the school, he is required to present the results of his work, such as his written examinations in the various studies, his test examples in arithmetic, his french, german, and spanish translations and exercises, various letters and forms, with four weekly specimens of improvement in writing, the whole to be formally submitted to the principal in an accompanying letter; the letter itself to exhibit what can be thus shown of improvement in writing, expression, and general knowledge. these budgets, accumulating month by month, are made to cover as much as possible of the student's school work, and to constitute the visible steps of his progress. besides this is a character record, kept in a small book assigned to each student, every student having free access to his own record, but not to that of any fellow student. each book contains the record of a student's deportment from the first to the last day of his attendance, with such comments and recommendations as his several teachers may think likely to be of encouragement or caution to him. in addition to the strictly technical training furnished by the college, there is given also not a little collateral instruction calculated to be of practical use to business men. for example, after roll call every morning some little time is spent in exercises designed to cultivate the art of intelligent expression of ideas. each day a number of students are appointed to report orally, in the assembly room, upon such matters or events mentioned in the previous day's newspapers as may strike the speaker as interesting or important. or the student may describe his personal observation of any event, invention, manufacture, or what not; or report upon the condition, history, or prospects of any art, trade, or business undertaking. this not to teach elocution, but to train the student to think while standing, and to express himself in a straightforward, manly way. instruction is also given in the languages likely to be required in business intercourse or correspondence; in phonography, so far as it may be required for business purposes; commercial law relative to contracts, negotiable paper, agencies, partnerships, insurance, and other business proceedings and relations; political economy, and incidentally any and every topic a knowledge of which may be of practical use to business men. in all this the ultimate end and aim of the instruction offered are practical workable results. mr. packard regards education as a tool. if the tool has no edge, is not adapted to its purpose, is not practically usable, it is worthless as a tool. this idea is kept prominent in all the work of the college, and its general results justify the position thus taken. the graduates are not turned out as finished business men, but as young men well started on the road toward that end. as mr. packard puts it: "their diplomas do not recommend them as bank cashiers or presidents, or as managers of large or small enterprises, but simply as having a knowledge of the duties of accountantship. they rarely fail to fulfill reasonable expectations; and they are not responsible for unreasonable ones." * * * * * american institute of architects. the fourteenth annual convention of the american institute of architects began in philadelphia, november . mr. thomas u. walter, of philadelphia, presided, and fifty or more prominent architects were present. in his annual address the president spoke of the tendency of the architectural world as decidedly in the direction of originality. but little attention is paid to the types of building drawn from the works of by-gone ages or to the mannerisms of the more recent past. progress in the development of the elements of taste and beauty, and the concretion of æsthetic principles with common sense in architectural design, are now everywhere apparent. the responsibilities of architects are greater than they have ever before been; the growing demand of the times calls for intelligent studies in all that relates to architecture, whether it be in the realm of æsthetics, in sciences that relate to construction, in the nature and properties of the materials used, in the atmosphere that surrounds us, or in the availability of the thousand-and-one useful and ingenious inventions that tend to promote the convenience and completeness of structures. papers were read by mr. a. j. blood, of new york, on "the best method of solving the tenement house problem;" mr. george t. mason, jr., of newport, on "the practice of american architects during the colonial period;" mr. robert briggs, of philadelphia, on "the ventilation of audience rooms;" mr. t. m. clark, of boston, on "french building laws, etc." the following named officers were elected: president, t. u. walter, philadelphia; treasurer, o. p. hatfield, new york; secretary, a. j. blood. trustees, r. m. hunt, h. m. congdon, j. cady, napoleon le brun, new york. committee on publication, r. m. upjohn, new york; t. m. clark, boston; john mcarthur, jr., philadelphia; a. j. blood, h. m. congdon, new york. committee on education, w. r. narr, boston; russell sturgis, new york; n. clifford ricker, champagne, ill.; henry van brunt, boston; alfred stone, providence. corresponding secretary, t. m. clark, boston. the time and place of the next annual convention were left to the board of trustees, with a request that washington be selected. * * * * * vennor's winter predictions. he communicates as follows to the albany _argus_: "december will, in all probability, open with little snow, but the weather will be cloudy, threatening snow falls. during the opening days of the month, dust, with the very light mixture of snow which may have fallen, will be swept in flurries by the gusty wind. there will probably be some snow from about the th of the month. with the second quarter of the month colder weather will probably set in with falls of snow. the farmers will be able to enjoy sleigh rides in the cold, exhilarating air, but good sleighing need not be expected until after the middle of the month. there will be a spell of mild weather about the th and th. after a brief interval of mild weather, during which more snow will fall, the third quarter of the month will probably see blustering and cold weather--a cold snap with heavy snow storms and consequent good sleighing. very cold weather may be expected during this quarter. the last quarter of the month will bring milder weather, but will terminate, probably, with heavy snow-falls and stormy weather; in fact, the heaviest snow falls will be toward the end of the month, and snow blockades may be looked for, the snow falls extending far to the southward, possibly as far as washington, with very stormy weather around new york and boston." mr. vennor's latest predictions are that the coming month will be "decidedly cold, with tremendous snow-falls during the latter half and early part of january, causing destructive blockades to railroads." * * * * * the london underground railway. the opening recently of the extension of the metropolitan railway to harrow, and the early commencement of another of the lines of the company, give especial prominence to it. the metropolitan underground railway is emphatically the great passenger railway of the country, for its few miles of line carry more than the hundreds of miles of line of companies such as the london and north western or great western. seventeen years ago--in --the metropolitan carried less than , , passengers, and in the full year's work of the following twelve months it carried less than , , . but year by year, almost without exception, the number of passengers has grown. in , over , , passengers were carried; in , over , , ; and in , over , , passengers traveled on the line. the years that have since passed have swollen that number. in , over , , were carried, but in the following year there was one of the few checks, and not till was the number of exceeded. in it rose to , , ; in it had advanced to , , ; in to , , ; and in to , , . in the present year there has been a further advance, the number carried for the first six months of the present year being , , . when it is borne in mind that this is equal to , passengers every hour, and that the length of line worked by the company's engines, including that of the "foreign" line worked, is slightly less than miles, the fecundity in traffic of the metropolitan district must be said to be marvelous. it is to be regretted that the official account from which these figures are given does not give any idea of the number of passengers in the different classes, for such a return would be of value. it is a marvelous fact in the history of locomotion that this great passenger traffic is worked with not more than engines, while the total number of carriages, , is in comparison with the number of travelers in them a marvel in railway history. but it is tolerably clear that there is yet a vast amount of undeveloped metropolitan traffic, and it is also certain that as that traffic is developed the future of the metropolitan as it attains more completeness will be brighter even than it has been in the past. the great city is more and more the mart of the world, and the traffic and travel to and in it must increase. that increase will be shared in considerable degree by the "underground" companies, and as they have shown that their capabilities of traffic are almost boundless, it may be expected that the oldest and the chief of these will in the early future know a growth as continuous if less rapid than in the past. we take the above from the _engineer_, london. in this city there are now existing miles of elevated steam railways for local passenger traffic. these roads have carried during the past year , , of passengers. in this service they employ locomotives and passenger cars. it is a terrible nuisance to have these locomotives and cars constantly whizzing through the public streets; still the roads are a great accommodation. the only underground railway in this city is that of the new york central and hudson river, miles in length, extending under fourth avenue from forty-second street to harlem river. over this road the enormous traffic of the central, harlem, and the new haven roads, with their connections, passes. but so removed from public sight are the cars and locomotives that the existence of this underground railway is almost forgotten. * * * * * tempering chisels. a practical mechanic communicates to the scientific american the following: in hardening and tempering a cold chisel care should be taken to have a gradual shading of temper. if there is a distinct boundary line of temper color between the hard cutting edge and softer shank portion, it will be very apt to break at or near that line. the cutting edge portion of the chisel should be supported by a backing of steel gradually diminishing in hardness; and so with all metal cutting tools that are subjected to heavy strain. not every workman becomes uniformly successful in this direction, for, in addition to dexterity, it requires a nice perception of degree of heat and of color in order to obtain the best result. * * * * * mr. a. a. knudson, of brooklyn, n. y., has lately perfected and patented a system of protecting oil tanks from lightning, which is approved by several prominent electricians. the invention includes a device for distributing a spray of water over the top of the tank for condensing the rising vapor and cooling the tank; a system of lightning conductors connected with a gutter surrounding the tank, and a hollow earth terminal connected with the gutter by a pipe, and designed to moisten the earth, and at the same time prevent the earth around the terminal from becoming saturated with oil. * * * * * a correspondant of the _christian union_, writing from constantinople, says that abd ul-hamid, the sultan of turkey, reads the scientific american, the engravings in which seem to specially interest him. the writer adds that whatever in literature the sultan may chance to hear of which he thinks may interest him, he has translated into turkish. * * * * * amateur mechanics. a simple single-acting steam engine. the great bugbear staring the amateur mechanic in the face when he contemplates making a small steam engine is the matter of boring the cylinder. to bore an iron cylinder on a foot lathe is difficult even when the lathe is provided with automatic feed gear, and it is almost impossible with the ordinary light lathe possessed by most amateurs. to bore a brass cylinder is easier, but even this is difficult, and the cylinder, when done, is unsatisfactory on account of the difficulty of adapting a durable piston to it. the engravings show a simple steam engine, which requires no difficult lathe work; in fact the whole of the work may be done on a very ordinary foot lathe. the engine is necessarily single-acting, but it is effective nevertheless, being about - h. p., with suitable steam supply. it is of sufficient size to run a foot lathe, scroll saw, or two or three sewing machines. the cylinder and piston are made from mandrel drawn brass tubing, which may be purchased in any desired quantity in new york city. the fittings are mostly of brass, that being an easy metal to work. the principal dimensions of the engine are as follows: cylinder.--internal diameter, ½ in.; thickness, / in.; length, - / in. piston.--external diameter, ½ in.; thickness, - in.; length, ¾ in. length of stroke. in. crank pin.--diameter, / in.; length of bearing surface, / in. connecting rod.--diameter, / in.; length between centers, ½ in. shaft.--diameter, / in.; diameter of bearings, / in.; length. in.; distance from bed to center of shaft, ½ in. flywheel.--diameter, in.; weight, lb. valve.--diameter of chamber, - in.; length, ¼ in.; width of valve face working over supply port, / in.; width of space under valve, / in.; length of the same, in.; distance from center of valve spindle to center of eccentric rod pin, / in. ports, supply--width, / inch.; length, in. exhaust.--width, / in.; length, in.; space between ports, - in. pipes.--steam supply, / in.; exhaust, / in. eccentric.--stroke, / in.; diameter, - / in. length of eccentric rod between centers, - / in. cut off, / thickness of base plate, / in. wooden base, ¼ in x in.: - / in. thick. thickness of plate supporting cylinder, / in. total height of engine, ¼ in. distance from base plate to under side of cylinder head. ¼ in. diameter of vertical posts, - in.; distance apart, ½ in.; length between shoulders ¼ in. base plate fastened to base with / in. bolts. the connecting rod, eccentric rod, crank pin, and shaft, are of steel. the eccentric-strap and flywheel are cast iron, and the other portions of the engine are of brass. the screw threads are all chased, and the flange, a, and head of the piston, f, in addition to being screwed, are further secured by soft solder. fig. shows the engine in perspective. fig is a side elevation, with parts broken away. fig. is a vertical transverse section. fig. is a partial plan view. fig. is a detail view of the upper end of the connecting rod and its connections; and fig. is a horizontal section taken through the middle of the valve chamber. the cylinder, a, is threaded externally for inch from its lower end, and the collar, a, / inch thick, is screwed on and soldered. the face of the collar is afterward turned true. the same thread answers for the nut which clamps the cylinder in the plate, b, and for the gland, b, of the stuffing box, which screws over the beveled end of the cylinder, and contains fibrous packing filled with asbestos or graphite. the posts, c, are shouldered at the ends and secured in their places by nuts. their bearing surface on the plate, d, is increased by the addition of a collar screwed on. the posts are made from drawn rods of brass, and need no turning except at the ends. [illustration: fig. .--simple single-acting steam engine] the cylinder head, e, which is a casting containing the valve chamber, is screwed in. the piston, f, fits the cylinder closely, but not necessarily steam tight. the head is screwed in and soldered, and the yoke, g, which receives the connecting rod pin, is screwed into the head. the connecting rod, h, is of steel with brass ends. the lower end, which receives the crank pin, is split, and provided with a tangent screw for taking up wear. the crank pin is secured in the crank disk, i, by a nut on the back. the eccentric rod, j, is of steel, screwed at its lower end into an eccentric strap of cast or wrought iron, which surrounds the eccentric, k. the valve, l, is slotted in the back to receive the valve spindle, by which it is oscillated. the ports are formed by drilling from the outside, and afterward forming the slot, with a graver or small sharp chisel. the supply port, for convenience, may be somewhat enlarged below. the holes for the exhaust port will be drilled through the hole into which the exhaust pipe is screwed. the chamber communicating with the exhaust is cored out in the casting. the easiest way to make the valve is to cut it out of a solid cylinder turned to fit the valve chamber. an engine of this kind will work well under a steam pressure of lb., and it may be run at the rate of to revolutions per minute. [illustration: side elevation. sectional, and detail views of simple steam engine] it is desirable to construct a flat pasteboard model to verify measurements and to get the proper adjustment of the valve before beginning the engine. m. * * * * * miscellaneous inventions. an improved finger ring has been patented by mr. david untermeyer, of new york city. the object of this invention is to furnish finger rings so constructed that they can be opened out to represent serpents, and which, when being worn, will give no indication of being anything more than rings. an improved heel skate-fastener has been patented by mr. elijah s. coon, of watertown, n.y. this invention consists, essentially, of a screw threaded hollow plug or thimble, a dirt plate for covering the opening in the plug, and a spring for holding the dirt plate in place. this fastener possesses several advantages over one that is permanently attached to the heel. being cylindrical, it is more easily connected, because the hole for its reception can be made with a common auger or bit without the necessity for lasting the boot or shoe or using a knife or chisel. being screw threaded it can be readily screwed into place with a common screwdriver; this also enables it to be screwed either in or out, in order to make it fit the heel key. the screw thread permits of screwing it in beyond the surface of the heel, so as to prevent it from wearing out by the ordinary wearing of the shoe. an improved velocipede has been patented by messrs. charles e. tripler and william h. roff, of new york city. the object of this invention is to obtain a more advantageous application of the propelling power than the ordinary cranks, to avoid the noise of pawls and ratchets, and to guard the velocipedes against being overturned should one of the rear wheels pass over an obstruction. mr. philip h. pax on, of camden, n. j., has patented a machine that will cut lozenges in a perfect manner, and will not be clogged by the gum and sugar of the lozenge dough. mr. john h. robertson, of new york city, has patented an improved mat, which consists of longitudinal metal bars provided with alternate mortised and tenoned ends, and composed of series of sockets united by webs and of wooden transverse rods entered through said sockets and held therein by vertical pins. mr. charles f. clapp, of ripon, wis, has patented a novel arrangement of a desk attachment for trunks. the desk and tray may be lifted from the trunk when the desk is either raised or lowered. a combined scraper, chopper, and dirter has been patented by messrs. francis a. hall and nathaniel b. milton, of monroe, la. the object of this invention is to furnish an implement so constructed as to bar off a row of plants, chop the plants to a stand, and dirt the plants at one passage along the row, and which shall be simple, convenient, and reliable. mr. hermann h. cammann, of new york city, has patented a basket so constructed that it can be compactly folded for transportation or storage. messrs. david h. seymour and henry r. a. boys, of barrie, ontario, canada, have patented an improvement in that class of devices that are designed to be applied to steam cylinders for introducing oil or tallow into the cylinder and upon the cylinder valves. it consists of an oil cup provided with a gas escape, a scum breaker, an interior gauge, and an adjustable feed pipe extension. mr. john h. conrad, of charlotte, mich., has patented a portable sliding gate which will dispense with hinges and which can be used in any width of opening. it may be readily connected with a temporary opening or gap made in the fence. an improved reversible pole and shaft for vehicles has been patented by mr. francis m. heuett, of jug tavern, ga. the object of this invention is to so combine the parts of shafts for vehicles that they may be readily transposed and re-employed to form the tongue without removing the thill arms or hounds from the mr. william jones, of kalamazoo, mich., has patented an improved box which is useful for various purposes, but is particularly intended for shipping fourth class mail matter. the feature of special novelty is the means of fastening the hinged cover. mr. louis j. halbert, of brooklyn, n. y., has patented an improved slate cleaner, which is simple, convenient, and effective. an improved boot, which is simple in its make, fits well, and is convenient to put on and take off, has been patented by ellene a. bailey, of st. charles, mo. the boot is provided with side seams, one of which is open at its lower end, and is provided with lacing, buttons, or a like device, so that it can be closed when the boot is on the wearer's foot. * * * * * the hercules beetle. in the handsome engraving herewith are shown the male and female of the hercules beetle (_dynastes hercules_) of brazil. the family of the _dynastidæ_ comprises some of the largest and most beautiful of the beetle race, and all of them are remarkable for enormous developments of the thorax and head. they are all large bodied and stout limbed, and by their great strength abundantly justify their generic name, _dynastes_, which is from the greek and signifies powerful. the larvæ of these beetles inhabit and feed upon decaying trees and other rotting vegetable matter, and correspond in size with the mature insects. most of them inhabit tropical regions, where they perform a valuable service in hastening the destruction of dead or fallen timber. an admirable example of this family of beetles is the one here represented. in the male of the hercules beetle the upper part of the thorax is prolonged into a single, downward curving horn fully three inches long, the entire length of the insect being about six inches. the head is prolonged into a similar horn, which curves upward, giving the head and thorax the appearance of two enormous jaws, resembling the claw of a lobster. the real jaws of the insect are underneath the lower horn, which projects from the forepart of the head. the under surface of the thorax-horn carries a ridge of stiff, short, golden-yellow hairs, and the under surface and edges of the abdomen are similarly ornamented. the head, thorax, and legs are shining black; the elytra, or wing-covers, are olive-green, dotted with black spots, and are much wrinkled. the wings are large and powerful. [illustration: the hercules beetle] the female hercules is quite unlike the male. it is much smaller, being not more than three and a half inches long, is without horns, and is covered with a brown hairy felt. these beetles are nocturnal in habit, and are rarely seen in the daytime, except in dark hiding places in the recesses of brazilian forests. * * * * * a poulterer's view of mechanical poultry raising. a prominent dealer in poultry, mr. h. w. knapp, of washington market, gives a discouraging opinion of the probable success of chicken raising by artificial means in this country. he said recently when questioned on this subject by a representative of the _evening post_: "i went to france to study the matter, for if it can be made to succeed it will make an immense fortune, as it has already done in paris. i was delighted with what i saw there, and the matter at first sight seems to be so fascinating that i do not wonder that new men here are always ready to take hold of it as soon as those who have bought dear experience are only too glad to get out of it. even clergymen and actors are bitten with the desire to transform so many pounds of corn into so many pounds of spring chicken. the now successful manager, mackaye, spent about a thousand dollars, in constructing hatching machines and artificial mothers in connecticut, but he found that the stage paid better, and his expensive devices may now be bought for the value of old tin. "enthusiasts will tell you that by the new discovery chickens may be made out of corn with absolute certainty. in paris this has been done; but the conditions are entirely different here. there the land is valuable, and they cannot devote large fields to a few hundred chickens; the french climate is so uniform that the markets of paris cannot be supplied from the south with produce which ripens or matures before that of the neighborhood of paris; the price of chickens is so high and labor so cheap that more care can be given with profit to one spring chicken than one of our poultry raisers could give to a dozen. here we have plenty of land, the climate south of us is so far advanced in warmth that even with steam we cannot raise poultry ahead of the south, and the margin of profit is so small that one failure with a large batch of chickens sweeps away the profits from several successful experiments. "when persons wanted me to go into the project i declined and was called an old fogy. one man spent a fortune on the enterprise in new jersey, and at first was hailed as a public benefactor. what was the result of all his outlay and work? he managed to hatch quantities of young chickens every february, but although he could fatten them by placing them in boxes and forcing a fattening mixture down their throats, he could not make them grow; they had no exercise; they remained puny little things, and another defect soon appeared: though fat they were tough and stringy. the breeder sent lots of them to me, and they looked fat and tender; but my customers complained that they could not be young, for they were tough and tasteless, and that i must have sold them aged dwarfs under the name of spring chickens. it was found absolutely necessary to let them run out of doors as soon as the weather allowed it, and by the time that they were ready for market the southern chickens were here and could be sold for less than these. the upshot of the business is that this breeder has sold out, and another man has now taken hold of a small part of his old establishment to try other methods of making it a success. "as to raising turkeys in that manner it will tail more disastrously than the chicken business. size and weight are wanted in turkeys; and that reminds me," continued mr. knapp, "that the newspapers ought to impress the country people with the necessity of improving their poultry stock; breeding in and in is ruining poultry; every year the stock we receive is deteriorating, and this is the cause. i could give you some striking examples from my experience of forty years in the business. some years ago we poulterers thought that ducks were going to disappear from bills of fare altogether; they were tasteless, worthless birds which people avoided. on long island a farmer made experiments in breeding with an old muscovy drake, tough as an alligator, and the common duck. the result was superb and has changed the whole duck industry. if the farmers of southern new jersey, the sandy country best suited to turkeys, would bring from the west a few hundred wild turkeys we should have an immediate improvement. i see no such turkey now as we had twenty years ago. the breast is narrow and the body runs to length; it is all neck and legs, and can be bought by the yard. rhode island sends us the best turkeys, but they are not what they used to be. if, instead of attempting to beat nature at her own game, the rich men who have money to spend would devote it to better breeding, there would be an improvement. i do not yet despair of seeing immense farms wholly devoted to raising better poultry than we yet have." * * * * * the embrace of the mantis. mr. addison ellsworth favors us with a transcript of a letter from mr. albert d. rust, of ennis, ellis county, texas, describing a remarkable exhibition of copulative cannibalism on the part of the mantis. the ferocious nature of these strange insects is well known, and is in striking contrast with the popular name, "praying mantis," which they have gained by the pious attitude they take while watching for the flies and other insects which they feed upon. about sunrise, august , , mr. rust's attention was attracted by a pair of mantis, whether _mantis religiosa_ or not, he was not sure, but from the length of the body and the shortness of the wings he was inclined to think them of some other species. the female had her arms tightly clasped around the head of the male, while his left arm was around her neck. mr. rust watched intently to see whether the embrace was one of war or for copulation. it proved to be both. as the two abdomens began to approach each other the female made a ferocious attack upon the male, greedily devouring his head, a part of the body, and all the arm that had encircled her neck. a moment after the eating began, mr. rust observed a complete union of the sexual organs, and the eating and copulation went on together. on being forcibly separated the female exhibited signs of fear at her headless mate, and it was with difficulty that they were brought together again. on being suddenly tossed upon the back of the female the male seized her with a grasp from which she could not extricate herself, and immediately the sexual union was renewed, to all appearances as perfectly as before. the pair were accidentally killed, otherwise, mr. rush thinks, the female would have continued her cannibalistic repast until she had devoured the entire body of her companion. this peculiarity of the mantis seems not to have been observed before, though their mutually destructive disposition has been noted by several. desiring to study the development of these insects, m. roesel raised a brood of them from a bag of eggs. though plentifully supplied with flies, the young mantis fought each other constantly, the stronger devouring the weaker, until but one was left. m. poiret was not more successful. when a pair of mantis were put together in a glass they fought viciously, the fight ending with the decapitation of the male and his being eaten by the female. * * * * * variegation of leaves. by james hogg. at the meeting of the association of nurserymen in chicago, last july, one of our prominent horticulturists described leaf variegation as a disease. incidentally this brought up the question: does the graft affect the stock upon which it is inserted? much confusion of ideas exists upon this subject, largely due to a loose application of the term disease. strictly speaking, this term is only applicable to that which shows the health of the plant to be impaired. it should be distinguished from aberrant or abnormal forms, for these are not necessarily indicative of disease. nobody thinks of saying that red or striped roses are diseased because they are departures in color from the white flower of the type species; or that white, yellow, or striped roses are diseased when the color of the type species is red. nobody thinks of saying that double flowers are evidences of disease in the plant, or that diminution in the size of leaves or variation in their form is a disease. why then should it be said that because leaves may become of some other color than green, or become party-colored, therefore they are diseased? if it be said that flowers are not leaves, and that therefore the analogy is not a good one, the reply is, that flowers in all their parts, and fruits also, are only leaves differently developed from the type. this fact is a proven one, and so admitted to be by all botanists and vegetable physiologists of the present day. if it be objected that by becoming double, flowers lose the power of reproducing the variety or species, the answer is, that this loss of power is not necessarily the result of disease, but may arise from various other causes. because an animal is castrated, it surely will not be claimed that therefore it is diseased. in man and in the higher animals the power of reproduction ceases at certain ages, but it cannot therefore be said that such men or animals are diseased. neither is a redundancy of parts an unequivocal evidence of disease. topknot fowls and ducks are as healthy as those which do not have such appendages, and a shetland pony is as healthy as a percheron horse, notwithstanding the difference in their size and weight. again, color in block or in variegation is not positive evidence of disease in animal life. the white caucasian is as healthy as the negro, the copper-colored malay as the red indian. the horse, ox, and hog run through white and red to black both in solid and party-color, and all are equally healthy; so with the rabbit, dog, cat, and others of our domestic animals. in wild animals, birds, reptiles, fishes, and insects, it is the same, so that mere difference in color or combinations of color are not _prima facie_ evidence of disease. but some will say this may be true of animal life, but not of plant life. that there is a strong and evident analogy, the one with the other, is now universally admitted by physiologists. formerly many physiologists considered leaf variegation a disease, because it generally ran in stripes lengthwise of the leaf or in spots. in the former case it was supposed to originate from disease in the leaf cells of the leaf stalk, which, as the cells grow longitudinally, naturally prolonged it to the end of the leaf. but the originating of varieties in which the variegation did not assume this form, with other considerations, has done much to upset this theory. in the variegated leaved snowberry we have the center and border of the leaf green, separated the one from the other by an isolated white or yellow zone. in the zebra-leaved eulalia and the zebra-leaved juncus, from japan, we have the variegation of the leaf transversely instead of longitudinally, so that according to the old theory we have the anomaly of a healthy portion of the leaf producing an unhealthy portion, and that again a healthy one, and thus alternately along the whole length of the leaf. when we dissect a leaf in its primal development, we find that its cells contain colorless globules, by botanists called chlorophyl or phyto-color; these undergo changes according as they are acted upon by light, oxygen, or other agents, producing green, yellow, red, and other tints. this chlorophyl only exists in the outer or superficial cells of the parenchyma or cellular tissue of the leaf, and thus differs from starch and other substances produced in the internal cells, from which the light is more or less excluded. it is a fatty or wax-like substance, readily dissolved in alcohol or ether. the primal color of all leaves and flowers is white or a pale yellowish hue, as can readily be seen by cutting open a leaf or flower bud. the seed leaves of the french bean are white when they come out of the earth, but they become green an hour afterward under the influence of bright sunshine. a case is on record where in a certain section, some miles in extent, in this country, about the time of the trees coming into leaf, the sun did not shine for twenty days; the leaves developed to nearly their full size, but were of a pale or whitish color; finally, one forenoon the sun shone out fully, and by the middle of the afternoon the trees were in full summer dress. these facts show that the green color of leaves is due to the action of light. variegation is sometimes produced independently of the chlorophyl, as in _begonia argyrostigma_ and _carduus marianus_, in which it is produced by a layer of air interposed between the epidermis or outer skin of the leaf and the cells beneath; this gives the leaf a bright, silvery appearance. to what, then, are we to ascribe leaf variegation? i think that it is entirely due to diminished root power; by this i do not mean that the roots are diseased, but that they are either in an aberrant or abnormal state; but disease cannot be predicated upon either of these states. to explain: everybody knows _spirea callosa_ to be a strong growing shrub, having umbels of rosy-colored flowers and strong, stout roots; the white flowered variety is quite dwarf, is more leafy and bushy than the species, and has more fibrous and delicate roots than the type; the crisp-leaved variety is still more dwarf, very bushy, and very leafy, and has very fine threadlike roots. this would indicate that the aberrance is in the roots; the two varieties are much more leafy in proportion to their size than the species, so that if the leaves controlled the roots, the latter should have been larger in proportion than those of the species. again, once when, in the autumn, i was preparing my greenhouse plants for their winter quarters, i cut back a "lady plymouth" geranium, which chanced to be set away in a cool and somewhat damp cellar. when discovered the following february and started into growth in the greenhouse it produced nothing but solid green leaves, and never afterward produced a variegated leaf. this i attributed to its having gained greater root power during its long season of rest. by this i mean that the roots had grown and greatly increased in size, although there had not been any leaf growth. that roots under certain circumstances do so is well known. the roots of fir trees have been found alive and growing forty five years after the trunks were felled. the same has occurred in an ash tree after its trunk had been sawn off level with the ground. a root of _ipomea sellowii_ has been known to keep on growing for twelve years after its top had been destroyed by frost; and in all that time it never made buds or leaves, yet it increased to seven times its original weight. the tuberous roots of some of the _tropoeolums_ will continue to grow and increase in size after the tops have been accidentally broken off; and potatoes buried so deep in the earth that they cannot produce tops will produce a crop of new potatoes. on the other hand, i have had an oak-leaved geranium overlooked in a corner of the greenhouse until it was almost dried up for lack of water. when its branches were pruned back and it was started into growth only one branch showed the almost black center of the leaf, all the rest were clear green. this was an evident case of diminished root power, but the plant grew as thriftily as ever. the lack of the dark marking in the leaves was equivalent to the variegation in other varieties, only in a reverse direction. in practice, when gardeners wish to produce an abnormal condition in a tree or plant, they will, if they wish to dwarf it, graft it on a species or variety of diminished root power, and contrariwise, if they wish to increase its growth, will graft it upon a stock of strong root power. but in neither case can the graft be said to be diseased by the action of the roots of the stock. when this root power is so far diminished as to produce complete albinism, the shoots from such roots appear to partake of this diminished power, and to lose the power of making roots, and thus become very difficult to propagate. it is sometimes said that albino cuttings cannot be rooted at all, but this is a mistake, for i have succeeded in striking such cuttings from the variegated leaved _hydrangea_. it required much care to do it; they did not, however, retain their albino character after they rooted and started into growth. albinism and white variegation in leaves appear to be due to the chlorophyl in such leaves being able to resist the action of the three (red, yellow, and blue) rays of light. what we call color in any substance or thing is due to its reflecting these different rays in various proportions of combination and absorbing the rest of them, the various proportions giving the various shades of color. white is due to the reflection of all of them, and black to the absorption of them. in some plants with variegated foliage we have the curious fact that the cells containing chlorophyl reflecting one color produce cells which reflect an entirely different color. in the coleus "lady burrill," for instance, the lower half of the leaf is of a deep violet-crimson color, and the upper half is golden yellow. in other varieties of coleus, in _perilla nankiensis_, and other plants, we have foliage without a particle of green in it, and yet they are perfectly healthy. this shows that green leaves are not absolutely necessary to the health of a plant. as a proof of leaf variegation being a disease, the speaker alluded to cited a case in which a green leaved abutilon, upon which a variegated leaved variety had been grafted, threw out a variegated leaved shoot below the graft. this can easily be explained. the growth of the trunk or stem of all exogenous plants, or those which increase in size on the outside of the stem, is brought about by the descent of certain formative tissue called cambium, elaborated by the leaves and descending between the old wood and the bark, where it is formed into alburnum or woody matter. some think that it is also formed by the roots and ascends from them as well as descending from the leaves. be this as it may, there is no doubt about its descent. in such comparatively soft-wooded, free growing plants as the abutilon the descent of the cambium is very free and in considerable quantity, so that the stock would soon be inclosed in a layer of it descending from the graft. when being converted into woody matter it also forms adventitious buds which under certain favorable circumstances will emit shoots of the same character as the graft from which it was derived. the graft is such cases may be said to inclose the stock in a tube of its own substance, leaving the stock unaffected otherwise. the variegated shoot in this case was in reality derived from the downward growth of the graft and not from the original stock, which was not therefore contaminated by the graft. in cases where the stock is of much slower growth than the graft, or the graft is inserted upon a stock of some other species, the descending cambium does not inclose the stock, but makes layers of wood on the stem of the graft, which thus, as is frequently seen, overgrows the stock, sometimes to such an extent as to make it unsightly. nobody ever saw an apple shoot from a crab stock, a pear from a quince stock, or a peach shoot from a plum stock. this is one of the arguments in favor of the view that cambium also rises from the roots. again, to show that the stock is not affected by the graft, or the graft by the stock, except as to root power, let any person graft a white beet upon a red beet, or contrariwise, when about the size of a goosequill, and when they have attained their full growth, by dividing the beet lengthwise he will find the line of demarkation between the colors perfectly distinct, neither of them running into the other. the theory that leaf variegation is a disease has been held by many distinguished botanists and is in nowise new. but this theory has been controverted, and we think successfully, by other botanists, and it is not now accepted by the more advanced vegetable physiologists. there are now so many acute and industrious students and observers in every department of science, and the accumulation of facts is so rapid and so great, that very many of the older theories are being set aside as not in accord with the newly discovered facts. a student brought up in institutions where the old theories are inculcated has afterward to spend half his time in unlearning what he had been previously taught, and the other half in studying the new facts brought to his notice and testing the theories promulgated by men of science. botanical science does not wholly consist in the classification and nomenclature of plants, but largely consists in a knowledge of vegetable anatomy and physiology, and these require much study and some knowledge of other sciences, such as chemistry, meteorology, geology, etc. without such general knowledge it is difficult to form a harmonious theory in regard to any of the phenomena of plant life. * * * * * vanilla, cinnamon, cocoanut. the following interesting facts concerning the cultivation of the above products in the island of ceylon, were given in mr. h. b. brady's recent address before the british pharmaceutical conference at swansea: the vanilla plant is trained on poles placed about twelve or eighteen inches apart--one planter has a line of plants about three miles in length. like the cardamom, it yields fruit after three years, and then continues producing its pods for an indefinite period. the cinnamon (_cinnamomum zeylanicum_) is, as its name indicates, a native of ceylon. it is cultivated on a light sandy soil about three miles from the sea, on the southwest coast of the island, from negumbo to matura. in its cultivated state it becomes really productive after the sixth year, and continues from forty to sixty years. the superintendent of the largest estate in this neighborhood stated that there were not less than fifteen varieties of cinnamon, sufficiently distinct in flavor to be easily recognized. the production of the best so injures the plants that it does not pay to cut this at any price under s. d. to s. per lb. the estate alluded to above yields from , to , lb. per annum; a uniform rate of ½ d. per lb. of finished bark is paid for the labor. cinnamon oil is produced from this bark by distillation; the mode is very primitive and wasteful. about lb. of bark, previously macerated in water, form one charge for the still, which is heated over a fire made of the spent bark of a previous distillation. each charge of bark yields about three ounces of oil, and two charges are worked daily in each still. the cultivation of the cocoanut tree and the production of the valuable cocoanut oil are two important cingalese occupations. these trees, it appears, do not grow with any luxuriance at a distance from human dwellings, a fact which may perhaps be accounted for by the benefit they derive from the smoke inseparable from the fires in human habitations. the cultivation of cocoanuts would seem to be decidedly profitable, as some , nuts per year are yielded by each acre, the selling price being £ per thousand, while the cost of cultivation is about £ per acre. in extracting the oil, the white pulp is removed and dried, roughly powdered, and pressed in similar machinery to the linseed oil crushing mills of this country. the dried pulp yields about per cent by weight of limpid, colorless oil, which in our climate forms the white mass so well known in pharmacy. * * * * * learning to tie knots. a correspondent suggests that it would be a handy accomplishment for schoolboys to be proficient in the handling, splicing, hitching, and knotting of ropes. he suggests the propriety of having the art taught in our public schools. a common jackknife and a few pieces of clothes line are the main appliances needed to impart the instruction with. he concludes it would not only be of use in ordinary daily life, but especially to those who handle merchandise and machinery. any one, he adds, who has noticed the clumsy haphazard manner in which boxes and goods are tied for hoisting or for loading upon trucks, will appreciate the advantage of practical instruction in this direction. probably a good plan, he further suggests, would be to have one schoolboy taught first by the master, and then let the pupil teach the other boys. our correspondent thinks most boys would consider it a nice pastime to practice during recess and at the dinner hour, so that no time would be taken from study or recitation time. * * * * * decisions relating to patents. supreme court of the united states pearce _vs._ mulford _et al._ appeal from the circuit court of the united states for the southern district of new york. . reissued patent no. , to shubael cottle, february , , for improvement in chains for necklaces, declared void, the first claim, if not for want of novelty, for want of patentability, and the second for want of novelty. . neither the tubing, nor the open spiral link formed of tubing, nor the process of making either the open or the closed link, nor the junction of closed and open spiral links in a chain, was invented by the patentee. . all improvement is not invention and entitled to protection as such. thus to entitle it it must be the product of some exercise of the inventive faculties, and it must involve something more than what is obvious to persons skilled in the art to which it relates. the decree of the circuit court is therefore reversed, and it is ordered that the bill be dismissed. by the commissioner of patents. dickson vs. kinsman.--interference.--telephone. the subject matter of the interference is defined in the preliminary declaration thereof as follows: the combination in one instrument of a transmitting telephone and a receiving telephone, so arranged that when the mouthpiece of the speaking or transmitting telephone is applied to the mouth of a person, the orifice of the receiving telephone will be applied to his ear. . while it is true that the unsupported allegations of an inventor, that he conceived an invention at a certain date, are not sufficient to establish such fact, the testimony of a party that he constructed and used a device at a certain time is admissible. . abandonment is an ill-favored finding, which cannot be presumed, but must be conclusively proven. the decision of the board of examiners-in-chief is reversed, and priority awarded to dickson. * * * * * characteristics of arctic winter. lieutenant schwatka, whose recent return from a successful expedition in search of the remains of sir john fanklin's ill-fated company, combats the prevalent opinion that the arctic winter, especially in the higher latitudes, is a period of dreary darkness. in latitude ° ' " n., the highest point ever reached by man, there are four hours and forty-two minutes of twilight on december , the shortest day in the year, in the northern hemisphere. in latitude ° ' n., the highest point where white men have wintered, there are six hours and two minutes in the shortest day; and latitude ° ' n., geographical miles nearer the north pole than markham reached, and geographical miles from that point, must yet be attained before the true plutonic zone, or that one in which there is no twilight whatsoever, even upon the shortest day of the year, can be said to have been entered by man. of course, about the beginning and ending of this twilight, it is very feeble and easily extinguished by even the slightest mists, but nevertheless it exists, and is quite appreciable on clear cold days, or nights, properly speaking. the north pole itself is only shrouded in perfect blackness from november to january , a period of seventy-seven days. supposing that the sun has set (supposing a circumpolar sea or body of water unlimited to vision) on september , not to rise until march , for that particular point, giving a period of about fifty days of uniformly varying twilight, the pole has about days of continuous daylight, days of varying twilight, and of perfect inky darkness (save when the moon has a northern declination) in the period of a typical year. during the period of a little over four days, the sun shines continuously on both the north and south poles at the same time, owing to refraction parallax, semi-diameter, and dip of the horizon. * * * * * the collins line of steamers. the breaking up of the baltic, the last of the famous collins line of steamships, calls out a number of interesting facts with regard to the history of the several vessels of that fleet. there were five in all, the adriatic, atlantic, pacific, arctic, and baltic. they were built and equipped in new york. their dimensions were: length, feet; beam, feet; depth of hold, ½ feet; capacity, , tons; machinery, , horse power. in size, speed, and appointments they surpassed any steamers then afloat, and they obtained a fair share of the passenger traffic. a fortune was expended in decorating the saloons. the entire cost of each steamer was not less than $ , , and notwithstanding their quick passages, the subsidy received, and the high rates of freight paid, the steamers ran for six years at great loss, and finally the company became bankrupt. the atlantic was the pioneer steamship of the line. she sailed from new york april , , and arrived in the mersey may , thus making the passage in about thirteen days, two of which were lost in repairing the machinery; the speed was reduced in order to prevent the floats from being torn from the paddle-wheels. the average time of the forty-two westward trips in the early days of the line was days hours and minutes, against the average of the then so called fastest line of steamers, days hours and minutes. in february, , the arctic made the passage from new york to liverpool in days and hours. the arctic was afterward run into by a french vessel at sea and only a few of her passengers were saved. the pacific was never heard from after sailing from liverpool, and all the persons on board were lost. the atlantic, after rotting and rusting at her wharf, was deprived of her machinery and converted into a sailing vessel, and was broken up in new york last year. the adriatic, the "queen of the fleet," made less than a half dozen voyages, was sold to the galway company, and is now used in the western islands as a coal hulk by an english company. the baltic was in the government service during the war as a supply vessel, and was afterward sold at auction; her machinery was removed and sold as old iron. she was then converted into a sailing ship, and of late years has been used as a grain carrying vessel between san francisco and great britain. on a recent voyage to boston she was strained to such an extent as to be made unseaworthy, and for that reason is to be broken up. one cannot but remark in this connection how small has been the advance in steamship building during the quarter century since the collins line was in its glory. * * * * * chinese women's feet. [illustration: chinese women's feet.] an american missionary, miss norwood, of swatow, recently described in a _times_ paragraph how the size of the foot is reduced in chinese women. the binding of the feet is not begun till the child has learnt to walk. the bandages are specially manufactured, and are about two inches wide and two yards long for the first year, five yards long for subsequent years. the end of the strip is laid on the inside of the foot at the instep, then carried over the toes, under the foot, and round the heel, the toes being thus drawn toward and over the sole, while a bulge is produced on the instep, and a deep indentation in the sole. successive layers of bandages are used till the strip is all used, and the end is then sewn tightly down. the foot is so squeezed upward that, in walking, only the ball of the great toe touches the ground. after a month the foot is put in hot water to soak some time; then the bandage is carefully unwound, much dead cuticle coming off with it. frequently, too, one or two toes may even drop off, in which case the woman feels afterward repaid by having smaller and more delicate feet. each time the bandage is taken off, the foot is kneaded to make the joints more flexible, and is then bound up again as quickly as possible with a fresh bandage, which is drawn up more tightly. during the first year the pain is so intense that the sufferer can do nothing, and for about two years the foot aches continually, and is the seat of a pain which is like the pricking of sharp needles. with continued rigorous binding the foot in two years becomes dead and ceases to ache, and the whole leg, from the knee downward, becomes shrunk, so as to be little more than skin and bone. when once formed, the "golden lily," as the chinese lady calls her delicate little foot, can never recover its original shape. our illustrations show the foot both bandaged and unbandaged, and are from photographs kindly forwarded by mr. j. w. bennington, r.n., who writes: "it is an error to suppose, as many do, that it is only the upper ten among the daughters of china that indulge in the luxury of 'golden lilies,' as it is extremely common among every class, even to the very poorest--notably the poor sewing women one sees in every chinese city and town, who can barely manage to hobble from house to house seeking work. the pain endured while under the operation is so severe and continuous that the poor girls never sleep for long periods without the aid of strong narcotics, and then only but fitfully; and it is from this constant suffering that the peculiar sullen or stolid look so often seen on the woman's face is derived. the origin of this custom is involved in mystery to the westerns. some say that the strong-minded among the ladies wanted to interfere in politics, and that there is a general liking for visiting, chattering, and gossip (and china women _can_ chatter and gossip), both and all of which inclinations their lords desired, and desire, to stop by crippling them." * * * * * to the alteration and metamorphism of rocks by the infiltration of rain and other meteoric waters, m. de koninck, of the belgian academy of sciences, assigns the cause of many hitherto unexplained phenomena in geology. * * * * * correspondence ice at high temperatures. _to the editor of the scientific american:_ your issues of october and contain some remarkable articles under the heading of "ice at high temperatures." prof. carnelley says; "in order to convert a solid into a liquid, the _pressure_ must be above a certain point, otherwise no amount of heat will melt the substance," as it passes at once from the sold state into the state of gas, subliming away without previous melting. and, "having come to this conclusion, it was easily foreseen that it would be possible to have solid ice at temperatures far above the ordinary melting point." the first conclusion of the professor is correct, but not new. the second conclusion is new, but very doubtful as to its correctness, and certainly does not follow as a sequence from his premise. if we try to heat ice in a vacuum, we cannot apply any heat to the ice direct, but only to the vessel containing the ice. the vessel may be much heated; but whether it will convey heat to the ice quick enough to heat it over °, and whether at all it can be heated over °, this is a question of a different nature. before crediting such a conclusion we must know more of the details of the experiments which the professor made in order to verify its correctness. when saying that "on one occasion a small quantity of water was frozen in a glass vessel which was so hot that it could not be touched by the hand without burning it," he evidently assumes that if the vessel is hot, the ice inside must be equally so; but this assumption is erroneous. faraday has made water to freeze in a red hot platina pot; the ice thus formed was not red hot like the platina, but was below the freezing point. just so with professor carnelley's glass vessel: the vessel was hot, but the ice inside no doubt was "ice cold." if the professor would surround a thermometer bulb with ice and then make the mercury rise above the freezing point, we would believe in "hot ice;" not before. until he does, we prefer to believe that the heat conveyed through the vessel to the ice is all absorbed in vaporizing the ice, and not in raising its temperature above °. professor carnelley's further statement, apparently proving his theory, that the ice at once liquefies as soon as pressure is admitted (say by admitting air), is readily accounted for by the phenomena connected with the "leydenfrost drop." water in a red hot vessel will vaporize off much slower than in a vessel heated a little above the boiling point, from the reason that in the red hot vessel no _real contact_ takes place between the vessel and the water. at the place where the two ought to touch, steam is formed quicker than it can escape, which steam prevents the contact between vessel and water; therefore, as no real contact takes place, the heat from the vessel can pass into the water but slowly, viz., in the proportion as it works itself through the layer of steam, which in itself is a bad conductor. just so in prof. carnelley's experiment: the heated glass vessel will convey heat to the ice only at those points where it touches the ice; at those points at once a formation of vapor takes place, which prevents an intimate contact between the glass and the ice, so that they do not really touch each other, consequently the heat can pass into the ice but slowly, having to work its way through the thin layer of rarefied vapor between the two. as soon as pressure is admitted by admitting atmospheric air, vapors can no longer form; an intimate contact will take place between the glass and the ice, and consequently the heat be conveyed over quick enough to make the ice melt away rapidly. the professor's experiments, therefore, so far as published, do not prove anything to justify his strange conclusion. it is perfectly true that in a vacuum of less than . mm. mercury pressure, no amount of heat will melt ice, all heat that can be conveyed to the ice being absorbed by vaporization. but before crediting the professor's further conclusion, that ice can be heated much above the freezing point, he must actually produce "hot ice," not only a hot vessel containing ice. n. j. brooklyn, n. y., october , . * * * * * schools of invention. the school of invention has not yet been established, but its germ is growing in the mechanical schools. this school, according to hon. w. h. ruffner, in _va. ed. journal_, will educate men, and women too, for the special career of inventing new things. why not? we already have something closely analogous in schools of design, where the pupil is trained to invent new forms or patterns, chiefly of an artistic or decorative character. the same idea will be applied to the invention of machinery, or improvements in machinery, or the adaptation of machinery to the accomplishment of special ends. inventions usually spring from individuals striving to lighten their own labor, or from some idea entering the brain of a genius. but we shall have professional inventors who will be called on to contrive original devices, and his success will depend on the sound and practical character of his prescriptions. * * * * * proposed exhibition of bathing appliances. the board of health of this city has recently been notified that a balneological exhibition, to illustrate the various systems of bathing, bath appliances, and kindred matters, is to be held in frankfort-on-main, germany, next summer. the exhibition will last from may to september, . h. h. heinrich, no. maiden lane, new york, inventor patentee, and sole manufacturer of the self-adjusting chronometer balance, which is not affected by "extremes of high and low temperatures, as fully demonstrated by a six months' test at the naval observatory at washington, d. c., showing results in temperatures from ° down to °, of - of a second only, unparalleled in the history of horology and certified to by theo f. kone. esq., commander u. s. n. in charge of the observatory. mr. heinrich is a practical working mechanic and adjuster of marine and pocket chronometers to positions and temperatures, and is now prepared to apply his new balance wheel to any fine timekeeping instrument, either for public or private use, he also repairs marine and pocket chronometers, as well as all kinds of complicated watches, broken or lost parts made new and adjusted. mr. heinrich was connected for many years with the principal manufacturers of england, geneva and locle, switzerland, and for the last fifteen years in the united states, and very recently with messrs. tiffany & co., of union square, new york. shipowners, captains naval and army officers, railroad and telegraph officials, physicians and horsemen, and all others wanting true time, should send to him. fine watches of the principal manufacturers, for whom he is their agent, constantly on hand. his office is connected by electric wires with the naval observatory's astronomical clock, through the western union telegraph, thus giving him daily new york's mean time. many years ago the british government made an offer of £ , for a chronometer for her navy, keeping better time than the ones in use, but no european horologist ever discovered the sequel which mr. heinrich has now worked out to perfection, overcoming the extremes, as stated above. with him is connected mr. john p. krugler for thirty years connected with the trade as salesman.--adv. * * * * * toope's felt and asbestos covering for steam pipes and other surfaces, illustrated on page , present volume, received a medal of excellence at the late american institute fair. see advertisement on another page. * * * * * business and personal. _the charge for insertion under this head is one dollar a line for each insertion; about eight words to a line. advertisements must be received at publication office as early as thursday morning to appear in next issue._ [symbol: hand] _the publishers of this paper guarantee to advertisers a circulation of not less than , copies every weekly issue._ chard's extra heavy machinery oil. chard's anti-corrosive cylinder oil. chard's patent lubricene and gear grease. r. j. chard, sole proprietor, burling slip, new york. wanted--superintendent for six thousand spindle cotton yarn mill. state salary and references, rosalie yarn mills, natchez, miss. use vacuum oil co.'s lubricating oil. rochester, n. y. , sawyers wanted. your full address for emerson's hand book of saws (free). over illustrations and pages of valuable information. how to straighten saws, etc. emerson, smith & co., beaver falls, fa. interesting to manufacturers and others.--the worldwide reputation of asbestos liquid paints, roofing, roof paints, steam pipe, boiler coverings, etc., has induced unscrupulous persons to sell and apply worthless articles, representing them as being made of asbestos. the use of asbestos in these and other materials for structural and mechanical purposes is patented, and the genuine are manufactured only by the h.w. johns m'f'g co., maiden lane, new york. three requisites--pens, pins, and needles. the two latter you can get of any make, but when you want a good pen get one of esterbrook's. for heavy punches, etc., see illustrated advertisement of hilles & jones, on page . frank's wood working mach'y. see illus. adv., p. . painters' list of good recipes. j. j. callow, clevel'd, o. improved speed indicator. accurate, reliable, and of a convenient size. sent by mail on receipt of $ . . e. h. gilman, doane st., boston, mass. astronomical telescopes, first quality & low prices, eye pieces, micrometers, etc. w. t. gregg, fulton st., n. y. engines. geo. f. shedd, waltham, mass. the mackinnon pen or fluid pencil. the commercial pen of the age. the only successful reservoir pen in the market. the only pen in the world with a diamond circle around the point. the only reservoir pen supplied with a gravitating valve: others substitute a spring, which soon gets out of order. the only pen accompanied by a written guarantee from the manufacturers. the only pen that will stand the test of time. a history of the mackinnon pen, its uses, prices, etc., free. mackinnon pen co. broadway, new york. among the numerous mowing machines now in use, none ranks so high as the eureka. it does perfect work and gives universal satisfaction. farmers in want of a mowing machine will consult their best interests by sending for illustrated circular, to eureka mower company, towanda, pa. peck's patent drop press. see adv., page . the inventors institute, cooper union building, new york. sales of patent rights negotiated and inventions exhibited for subscribers. send for circular. fragrant vanity fair tobacco and cigarettes. first prize medals--vienna, : philadelphia. ; paris, : sydney, --awarded wm. s. kimball & co., rochester, n. y. superior malleable castings at moderate rates of richard p. pim, wilmington, del. wood working machinery of improved design and workmanship. cordesman, egan & co., cincinnati, o. the e. stebbins manuf'g co. (brightwood, p. o.), springfield, mass., are prepared to furnish all kinds of brass and composition castings at short notice; also babbitt metal. the quality of the work is what has given this foundry its high reputation. all work guaranteed. the " " lace cutter by mail for cts.; discount to the trade. sterling elliott, dover st., boston, mass. the tools, fixtures, and patterns of the taunton foundry and machine company for sale, by the george place machinery agency, chambers st., new york. improved rock drills and air compressors, illustrated catalogues and information gladly furnished. address ingersoll rock drill co., ½ park place. n. y. mineral lands prospected, artesian wells bored, by pa diamond drill co. box . pottsville, pa. see p. . experts in patent causes and mechanical counsel. park benjamin & bro., astor house, new york. corrugated wrought iron for tires on traction engines, etc. sole mfrs. h. lloyd, son & co., pittsb'g, pa. malleable and gray iron castings, all descriptions, by erie malleable iron company, limited, erie, pa. power, foot, and hand presses for metal workers. lowest prices. peerless punch & shear co. dey st., n. y. recipes and information on all industrial processes. park benjamin's expert office, astor house, n. y. for the best stave, barrel, keg, and hogshead machinery, address h. a. crossley, cleveland, ohio. national steel tube cleaner for boiler tubes. adjustable, durable. chalmers-spence co., john st., n. y. for mill mach'y & mill furnishing, see illus. adv. p. . the brown automatic cut-off engine; unexcelled for workmanship, economy, and durability. write for information. c. h. brown & co., fitchburg, mass. gun powder pile drivers, thos. shaw, ridge avenue, philadelphia, pa. for separators, farm & vertical engines, see adv. p. . for patent shapers and planers, see ills. adv. p. . best oak tanned leather belting. wm. f. forepaugh, jr., & bros., jefferson st., philadelphia, pa. stave, barrel, keg, and hogshead machinery a specialty, by e. & b. holmes, buffalo, n.y. split pulleys at low prices, and of same strength and appearance as whole pulleys. yocom & son's shafting works, drinker st., philadelphia. pa. c. b. rogers & co., norwich, conn., wood working machinery of every kind. see adv., page . national institute of steam and mechanical engineering, bridgeport, conn. blast furnace construction and management. the metallurgy of iron and steel. practical instruction in steam engineering, and a good situation when competent. send for pamphlet. reed's sectional covering for steam surfaces; any one can apply it; can be removed and replaced without injury. j. a. locke, agt., cortlandt st., n.y. downer's cleaning and polishing oil for bright metals, is the oldest and best in the market. highly recommended by the new york, boston, and other fire departments throughout the country. for quickness of cleaning and luster produced it has no equal. sample five gallon can be sent c. o. d. for $ . a. h. downer, peck slip, new york. presses. dies, and tools for working sheet metal, etc. fruit & other can tools. bliss & williams, b'klyn, n.y. for pat. safety elevators, hoisting engines. friction clutch pulleys, cut-off coupling, see frisbie's ad. p. . nickel plating.--sole manufacturers cast nickel anodes, pure nickel salts, importers vienna lime, crocus, etc. condit. hanson & van winkle, newark, n. j., and and liberty st., new york. sheet metal presses. ferracute co., bridgeton, n. j. wright's patent steam engine, with automatic cut off. the best engine made. for prices, address william wright, manufacturer, newburgh, n. y. machine knives for wood-working machinery, book binders, and paper mills. also manufacturers of soloman's parallel vise, taylor, stiles & co., riegelsville, n. j. rollstone mac. co.'s wood working mach'y ad. p. . silent injector, blower, and exhauster. see adv. p. . fire brick, tile, and clay retorts, all shapes. borgner & o'brien, m'f'rs, d st., above race, phila., pa. clark rubber wheels adv. see page . diamond saws. j. dickinson, nassau st., n.y. steam hammers, improved hydraulic jacks, and tube expanders. r. dudgeon, columbia st., new york. eclipse portable engine. see illustrated adv., p. . peerless colors--for coloring mortar. french, richards & co., callowhill st., philadelphia, pa. tight and slack barrel machinery a specialty. john greenwood & co., rochester, n. y. see illus. adv. p. . elevators, freight and passenger, shafting, pulleys and hangers. l. s. graves & son, rochester, n.y. steam engines; eclipse safety sectional boiler. lambertville iron works, lambertville, n. j. see ad. p. . magic lanterns, stereopticons, and views of all kinds and prices for public exhibitions. a profitable business for a person with small capital. also lanterns for home amusement, etc. send stamp for page catalogue to mcallister, m'f'g optician, nassau st., new york. lenses for constructing telescopes, as in sci. am. supplement, no. , $ . per set; postage, cts. the same, with eye piece handsomely mounted in brass, . . mcallister, m'f'g optician, nassau st., n. y. for best low price planer and matcher, and latest improved sash, door, and blind machinery, send for catalogue to rowley & hermance, williamsport, pa. the only economical and practical gas engine in the market is the new "otto" silent, built by schleicher, schumm & co., philadelphia, pa. send for circular. penfield (pulley) blocks, lockport n. y. see ad. p. . to h. p. steam engines. see adv. p. . tyson vase engine, small motor. - h. p., efficient and non-explosive: price $ see illus. adv., page . for yale mills and engines, see page . lightning screw plates and labor-saving tools. p. . * * * * * patents issued to americans. from november to november , , inclusive. book binding, l. finger, boston, mass. draining and sewerage. g. e. waring newport, r. i. electric gas lighter, g. d. bancroft. boston, mass. electric signal. eh johnson _et al._, menlo park, n. j. horse nail manufacture, s. s. putnam. boston, mass. hygienic confection, t. s. lambert _et al._, new york city. looms, f. o. tucker, hartford, conn reflectors for lamps. j. s. goldsmith, new york city. railroad vehicles, e. r. esmond _et al._. new york city. sewing machine. g. f. newell, greenfield. mass. steam boilers, d. sutton. cincinnati. ohio. steam boilers, w. d. dickey, new york city. toy money box, j. e. walter. new york city. trucks, hand., e. j. lyburn, fredericksburg, u. s. a. * * * * * notes and queries hints to correspondents. no attention will be paid to communications unless accompanied with the full name and address of the writer. names and addresses of correspondents will not be given to inquirers. we renew our request that correspondents, in referring to former answers or articles, will be kind enough to name the date of the paper and the page, or the number of the question. correspondents whose inquiries do not appear after a reasonable time should repeat them. if not then published, they may conclude that, for good reasons, the editor declines them. persons desiring special information which is purely of a personal character, and not of general interest, should remit from $ to $ , according to the subject, as we cannot be expected to spend time and labor to obtain such information without remuneration. any numbers of the scientific american supplement referred to in these columns may be had at this office. price cents each. * * * * * ( ) l. l. asks: . how can i grind and polish quartz and agate rock, and what kind of grinding and polishing material should i use? a. quartz and agate are slit with a thin iron disk supplied with diamond dust moistened with brick oil. the rough grinding is done on a lead wheel supplied with coarse emery and water. the smoothing is done with a lead lap and fine emery, and the polishing may be accomplished by means of a lead lap, whose surface is hacked and supplied with rottenstone and water. . what is the best method of polishing steel? a. the usual method is to grind first on a coarse wet stone, then on a fine wet stone, then on a lead lap supplied with fine emery and oil, and finally polish on a buff wheel supplied with dry crocus and revolving rather slowly. ( ) r. l. j. asks how to make copying black and red inks. a. . bruised aleppo nutgalls, lb.; water, gallon; boil in a copper vessel for an hour, adding water to make up for that lost by evaporation; strain and again boil the galls with a gallon of water and strain; mix the liquors, and add immediately oz. of copperas in coarse powder and oz. of gum arabic; agitate until solution of these latter is effected, add a few drops of solution of potassium permanganate, strain through a piece of hair cloth, and after permitting to settle, bottle. the addition of a little extract of logwood will render the ink blacker when first written with. half an ounce of sugar to the gallon will render it a good copying ink. . shellac, oz.; borax, oz.; water, quart; boil till dissolved, and add oz. of gum arabic dissolved in a little hot water; boil and add enough of a well triturated mixture of equal parts indigo and lampblack to produce the proper color; after standing several hours draw off and bottle. . half a drachm of powdered drop lake and grains of powdered gum arabic dissolved in oz. of ammonia water constitute one of the finest red or carmine inks. ( ) x. inquires: what is the rule for making a counterbalanced face wheel for engines? a. it is a common practice to place the counter weight directly opposite the crank, with its center of gravity at the same distance from the center of the shaft as the center of the crank pin, making its weight equal to weight of piston, piston rod, crosshead, and crank pin, plus half the weight of the connecting rod. ( ) a. r. asks: what is the best way to remove cinders from the eye? a. a small camel's hair brush dipped in water and passed over the ball of the eye on raising the lid. the operation requires no skill, takes but a moment, and instantly removes any cinder or particle of dust or dirt without inflaming the eye. ( ) d. f. h. asks: can i move a piston in a half inch glass tube by the expansion of mercury? a. yes, but you will require a long tube to get any appreciable motion of the piston. ( ) j. w. asks: what size of a bore and what length of a stroke i would want for a rocking valve engine of half a horse power? a. about inches cylinder and inch stroke, depending upon pressure and velocity. ( ) r. w. h. writes: in a recent discussion on hot air and steam portable engines it was decided to ask your opinion, which should be final. water is scarce, though enough to use steam is easily procured. the country is hilly, so that lightness is desirable. the power wanted is horse, and movable, that is, on wheels. which will be best, hot air engine or steam engine? which consumes most coal for a given power? which will be cheapest in above case? a. for small powers the hot air engine is most economical, but we do not think it adapted to your purpose. we would recommend the steam engine for a portable power. ( ) j. c. t. writes: . i have a water tank for supplying my boiler, which is made of no. galvanized iron; size inches by feet inches. how many gallons will it hold? a. gallons. . will it be better to have it painted inside? a. yes. . how many years will the tank wear under favorable circumstances, using well water? a. depends upon the care taken of it. ( ) w. h. c. asks: is there any way of deadening the noise of machinery overhead from the engine room below? the noise comes from machinery in the weave room of an alpaca mill. a. this is generally accomplished by setting the legs of the machines on thick pieces of india-rubber or other non-conductor of sound. ( ) g. h. asks: how can i mount photos on glass and color them? a. take a strongly printed photograph on paper, and saturate it from the back with a rag dipped in castor oil. carefully rub off all excess from the surface after obtaining thorough transparency. take a piece of glass an inch larger all round than the print, pour upon it dilute gelatin, and then "squeegee" the print and glass together. allow it to dry, and then work in artists' oil colors from the back until you get the proper effect from the front. both landscapes and portraits can be effectively colored by the above method without any great skill being required. ( ) c. w. s. asks: . is there any practical and effective method known for cutting screws by connecting the slide rest with the mandrel of the lathe by gears or otherwise? a. this can be done in this way: attach a spur wheel to the back of the face plate. mount a similar wheel on a short hollow shaft, and support the shaft by an arm bolted to the lathe bed so that the two spur wheels will mesh together. fit right and left hand leading screws to the hollow shaft of the second spur wheel, and drill a hole through them as well as through the hollow shaft to receive the fastening pin. now remove the longitudinal feed screw of the slide rest and attach to one side of the carriage an adjustable socket for receiving nuts filled to the leading screws. the number of leading screws required will depend of course on the variety of threads it is desired to cut unless a change of gear is provided. . a writer in a foreign journal claims to make slides, or v-shaped pieces for slide rests, eccentric chucks, etc., on his lathe. is any such process known here, or any process within the capabilities of an amateur mechanic by which the planing machine can be dispensed with? a. for small work held between the lathe centers a milling device fitted to the slide rest in place of the tool post will answer an excellent purpose. this device consists of a mandrel carrying at one end the cutter and at the other end a large pulley. this mandrel is journaled in a hinged frame supported by a block replacing the tool post, and is adjusted as to height by a screw passing through an arm projecting from the supporting block. the direction of the belt is adapted to this device by means of pulleys. ( ) j. e. b. asks: . what is the best turbine water wheel now in use? a. there are several wheels in market that seem equally good. you should examine all of them and decide from your own observation which is best. . what is the rule for finding the horse power of water acting through a turbine wheel which utilizes per cent of the water? a. finding the weight of water falling over the dam and its velocity in feet per minute, multiply the weight in pounds by the velocity, and the result is foot pounds, divided by , , the quotient is theoretical horse power; if your wheel gives out per cent. then per cent of that result is the horse power of the wheel. . how can i calculate the capacity of a belt? a. you will find an exhaustive article on the subject of belts on pp. , , vol. , scientific american, which contains the information you desire. . what machine now in use is the best, all things considered, for the manufacture of ground wood pulp? where are they manufactured? a. this information can probably be obtained by inserting an advertisement in the business and personal column of this paper. ( ) c. a. r writes: wishing to renew my leclanche batteries, which were giving out, i bought some new empty porous cells. please give the following information: . can i use the carbon plates of the old elements over again? if so, do they need to undergo any washing or soaking; or are they as good as ever? a. yes. soak them for a few hours in warm water. . is there anything i must add to the granular manganese with which i fill the cells, in order to obtain maximum power and endurance? some makers add pulverized or even coarsely broken carbon. is it an advantage? a. it is an advantage to add granulated carbon to the manganese. use equal parts of each. . what is the exact composition of the curdy mass which forms around and especially underneath the zincs of newly mounted and old gravity batteries. is this substance formed naturally, or is it the result of using poor zinc or sulphate of copper? a. it is copper, and should be removed, for it weakens the battery. it is the result of placing the zinc in the sulphate of copper solution. . is there any real advantage in amalgamating the zincs of the above batteries? a. no. . is there a speedy way of cleaning them when coated with this substance? a. they can be cleaned by scraping. . at certain occasions my electric bells began ringing without anybody apparently closing the circuit. i often notice that if i unjoin the batteries and let them remain thus for a few hours, on reconnecting them the bells would work all right for a week, sometimes a fortnight, when the same trouble would again occur. can you in any way explain this phenomenon? the batteries are not placed in a very dry part of the house, but the wires, which run pretty closely together, are nearly all exposed, so that i can control the slightest corrosion or uncovering of the conductors. a. there must be some accidental closing of the circuit. we could not explain the action of your line without seeing it. ( ) j. e. e. asks: what is the number of layers of wire, and the size used for the primary of the induction coil in the blake transmitter, and as near as you can the amount used for secondary? a. for primary, use three layers of no. magnet wire, and for the secondary use twelve or fourteen layers of no. silk covered copper wire. the resistance of the secondary wire should be from to ohms. ( ) j. m. i. asks how to make a barometer by coloring ribbon, so that they will change color, indicating weather changes. a. use a moderately strong solution of chloride of cobalt in water. ( ) o. c. h. writes: in reply to r. a. r., question , in scientific american, december , i will say that some months ago i was engaged in running a saw mill, lathe, and shingle factory; was troubled with two hot boxes, and frequently had to stop and apply ice. seeing in the scientific american a reference to the use of plumbago, i sent for some, and after three or four applications was troubled no more with hot boxes. ( ) f. w. asks: what is the best way for return pipe to go into the boiler from radiators--steam at lb. per square inch, fall feet? a. if your job is properly piped you can bring your return pipe in at any convenient place in your boiler below the water line. if you go into the feed pipe, have your connection inside all other valves. ( ) l. t. g. writes: . i have four cells of carbon battery; the solutions are bichromate of potash and sulphuric acid. also three cells of the smee; sulphuric acid one part, to ten of water; and the four cells of the carbon battery are not sufficient to run my small electro-magnetic engine, for more than two or three minutes. i wish to know if it would be injurious to either one of the batteries if i should unite them both in one circuit, to run the engine, for about one or two hours at a time. a. the batteries will not be injured, but they will not work well together. better increase the number of carbon elements. . will either of the above batteries freeze in winter, or will cold weather affect their working? a. they will not freeze, but it is better to keep them at a temperature above freezing . is it always best to use the largest wire in connecting batteries with any instrument, say, above no. or no. wire, as the larger the wire the less the resistance, thereby getting nearly the full power of the battery? a. yes. . what purposes are quantity and intensity electricity best suited for respectively? a. batteries are arranged for quantity or intensity according to the work to be done. the maximum effect is obtained when the battery elements are combined, so that the total resistance in the elements is equal to the resistance of the rest of the circuit. ( ) j. h. asks: which would be the strongest, two -inch by -inch joists nailed together, or one -inch by -inch joist? a. one -inch by -inch. ( ) j. k. b. writes: i suppose every experimenter who uses a carbon battery has been troubled by the uncertainty of the carbon connection. the makers of the grenet battery seem to have solved the problem. can you tell us through your correspondence column what solder they use, and how they make it stick? a. the carbon is coated with copper by electro-deposition; this coating is readily soldered to the carbon support with common soft solder. ( ) m. d. m. asks: . is there a difference in a steam engine between the boiler pressure and the pressure on the piston when the piston is moving feet per minute? a. yes. . about what difference? a. from to lb., depending upon size and length of steam pipe. . does the difference between them vary with a difference in the motion of the piston in the same engine? a. not appreciably within usual limits of speed. ( ) f. writes: we have just closed up our steam stone works for this season, and we wish to know what is best to coat the inside of our steam boilers to keep them from rusting. some say black oil, and others common tallow: which do you recommend as the best? a. we think the black oil quite as good and cheaper than tallow. have the surfaces thoroughly cleaned before applying the oil. ( ) o. h. asks for a cheap and easy way of amalgamating battery zincs. a. it depends on the kind of battery. in the fuller the mercury is placed in the porous cell with the zinc. in bichromate batteries all that is necessary is to dip the zinc in the bichromate solution and then pour on a drop or two of mercury. it soon spreads over the entire surface of the zinc. another method is to dip the zincs in dilute sulphuric acid and then pour on a little mercury, but these methods, except in the case of the fuller battery, are wasteful of mercury. it is better to apply an amalgamating solution with a brush. this solution is made by dissolving one part (by weight) of mercury in five parts of nitro-muriatic acid (nitric acid one part, muriatic acid three parts), heating the solution moderately to quicken the action; and, after complete solution, add five parts more of nitro-muriatic acid. ( ) g. w. asks: . would a perfectly round ball of the same specific gravity throughout lie still on a level surface? a. yes. . can a mechanic's square be made so true that a four-inch block may be made exactly square by such an instrument? a. yes. ( ) w. h. asks: . what is the weight of a boiler feet long, inches diameter, ¼ inch thick? a. with two flues, inches diameter, , lb. . what is the contents (in gallons) of a tank feet deep, feet in diameter, top and bottom diameters being equal? please give me a formula. a. area of feet diameter = . x feet deep = , cubic feet, and, allowing ½ gallons per cubic foot = , x . = , gallons. ( ) c. l. w. writes: i have constructed a small induction coil to be used for giving shocks. it is inches long. the primary coil is wound with layers of no. cotton covered wire, and the secondary consists of about layers of no. silk covered. . how many cells and what kind of battery shall i use to get the best results? a. for temporary use one cell of grenet battery would answer, but for continued use some form of sulphate of copper battery is to be preferred. . is it necessary that the spring and screw in the interrupter should be coated with platinum? a. yes; otherwise they would soon burn out. ( ) h. c. p. writes: in the scientific american of september , mr. b. y. d., query , asks whether a sun dial, made for latitude ° ', can be utilized in latitude ° ' for showing correct time. to make his dial available in the lower latitudes, he has only to lift the south side, so as to give the face a slope to the north, equal to the difference of the latitude, in this case ° '. for then the plane of the gnomon being in the plane of the meridian, the edge of the gnomon casting the shadow will be parallel with the earth's axis; and the face of the dial will be parallel with the horizon of the latitude for which the dial was made, and the graduation will show the time required; that is, on the supposition that it was correctly made, and for a horizontal dial. ( ) o. m. m. asks for a cheap process of plating steel case knives with tin. a. clean the metal thoroughly by boiling in strong potash water, rinsing, pickling in dilute sulphuric acid, and scouring with a stiff brush and fine sand. pass through strong aqueous salammoniac solution, then plunge in hot oil (palm or tallow). when thoroughly heated remove and dip in a pot of fused tin (grain tin) covered with tallow. when tinned, drain in oil pot and rub with a bunch of hemp. clean and polish in hot sawdust. ( ) v. r. p. writes: i have an aquarium which contains - / gallons of water. how many fish must i have in it--average length of fish ½ to inches to insure the health of the fish? at present, i refill the aquarium semi-weekly. please tell me a process by which i can lengthen the time. a. put in three fish, ½ inches in length, to one gallon of water, one small bunch of fresh water plants to one gallon of water. tadpoles (after they have cast their branchia or gills), newts, and rock fish can be used to the extent of six to the gallon. the aquatic plants will supply the fish with sufficient oxygen, so that the water will seldom require changing. ( ) a. s. writes: i am about to construct an aqueduct , feet in length, the water level differing feet. by placing a forcing pump in the valley i could then raise the water to a height of feet, and having erected a tank at that height and connected it by means of pipes with another tank , feet distant, but on the same level, the water according to a law of nature would travel over the distance of , feet. but finding it very difficult to erect tank feet high, i would prefer to construct the whole on the incline. will the forcing pump having just power enough to raise the water feet perpendicularly into the tank have sufficient power to force it into a tank of the same elevation through , feet of pipe running on the incline, or must i have more power, and how much more? a. the forcing pump must have enough more power to overcome its own additional friction and the friction of water in the long inclined pipe. allow per cent more power at least. * * * * * minerals, etc.--specimens have been received from the following correspondents, and examined, with the results stated: box marked c. h. (no letter.)-- . and . garnetiferous quartz rock. and . micaceous quartz rock. . granite. . basalt with traces of chalcopyrite.--l. c. g.--they are fossil sharks' teeth, common in marl beds.--j. e. c.-- . iron sulphide and lead sulphide. . quartzite, with traces of galena and molybdic sulphide. and . dolomite. . fossiliferous argillaceous limestone, containing traces of lead sulphide. . lead sulphide in argillite.--c. t. m.-- . a silicious kaolin. . similar to no. . useful if mixed with finer clay for white ware. . silicions carbonate of lime--some of this would probably make fair cement. . brick--the clay from which this was made would probably be useful to potters. and are very silicious clays. * * * * * communications received. liniment. by j. l. t. seen and tangible and the unseen and intangible. by j.l.t. on cheap railroads. by r. p. n. on a meteor. by w. e. c. * * * * * [official.] index of inventions for which letters patent of the united states were granted in the week ending: november , , and each bearing that date. [those marked (r) are reissued patents.] * * * * * a printed copy of the specification and drawing of any patent in the annexed list, also of any patent issued since , will be furnished from this office for one dollar. in ordering please state the number and date of the patent desired and remit to munn & co., park row, new york city. we also furnish copies of patents granted prior to ; but at increased cost, as the specifications not being printed, must be copied by hand. alloy for coating metals, j. b. jones , axle box, car, h. hazel , bag holder and truck therefor, l. h. aldrich , baling press, w. duke , band cutting and removing apparatus. w. gray , basket splints, machine for shaving, a. b. fisher , belt shifting mechanism for washing machines, l. sternberger , belt shipper, b. h. hadley , bias cutter, w. f. hood , bit brace, n. spofford , bit stock, q. s. backus , book case, m. c. dodge , book holder, w. b. daugherty , boot and shoe heel, j. g. ross , boot and shoe soles, machine for forming imitation fair stitches to the edges of, tayman & bennor , boot treeing machine, e. f. grandy , borer and excavotor, earth, j. w. carley , bottle wrapper, m. v. kacer , bridle front, b. a. wilson , buckle, d. c. bassett , buckle, harness, b. h. cross , butter worker, cornish & curtis , button and stud, n. nelson , buttonhole for cuffs, etc., c. h. shaw , can, e. p. fox , can opener, w. e. brock , car brake, g. bressler , car brake, c. v. rote , car brake, g. a. small , car coupling, w. i. ely , car door fastener, briggs & dougherty , car, railway, g. l. waitt , car starter, j. ladner , car, stock, w. neracher , car wheel, e. l. taylor , cars, shield for railway mason & hanson , caster, trunk, j. simmons , chain, j. m. dodge , chains, device for making, h. wexel , chair, w. r. clough , chandelier, extension, t. d. hotchkiss , cheese curd sifter and picker, f. m. cummings , churn, m. f. mitchel , clock, traveling, h. reinecke , clock winding and gas cock mechanism, combined, g. p. ganster , clothes wringer, s. huffman , coal fork, t. r. way , coin, device for holding, counting, and delivering, van slyke & nesom , collar and cuff folding machine, m. hermann , confectioners' forms and their application, w. e. h. sommer , corn husks, apparatus for cutting, w. a. wright , corn husks, disintegrating, w. a. wright , corset, c. f. allen , cotton picker, g. risler , cotton press, s. stucky , cradle and carriage, combined, g. f. doyle , crank movements, apparatus for overcoming the dead point in, p. e. jay , crimping pin, c. d. thompson , cuff fastener and supporter, a. b. case , cultivator and seeder, combined, j. d. chichester , current and tide water wheel, h. fake , currycomb, m. sweet , curtain fixture, h. seehausen , draught equalizer, f. h. sandefer drawer lock, g. e. bendix , drilling machine, t. naish , drip pan for oil barrels, c. e. laverty , electric light burner, j. sarcia , electric lights or motors, automatic cut-out apparatus for, c. f. brush , electric machines, rotating armature for dynamo, e. weston , electrical switch board, j. w. see , embroidering machines, jacquard attachment for, m. umstadter (r) , , , end board, wagon, h. a. riggs , excelsior machine, c. howes , explosive compound, c. a. morse , eyeglasses, r. kabus . faucet attachment, c. a. raggio , feed bag, t. r. lowerre , fence post, wire, ticknor & bebee , ferric oxide and cupric chloride, manufacture of, j. f. n. macay , filter, coffee and tea, t. fitzgerald, jr. , filter, reversible, r. s. jennings , firearm, breech-loading, j. l. volkel , fire escape, quintavalle & lindberg , fires, process of and apparatus for extinguishing, j. h. campbell , foot, artificial, a. a. marks , fruit drier, g. p. & l. j. lee , fuel burning apparatus, j. wolstenholme , galvanic battery, g. l. leclanché , gas making apparatus, c. f. dieterich , gas pressure regulator, p. noyes , gas, process of and apparatus for manufacturing illuminating, granger & collins, jr. , gate, l. p. 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ironing machine, j. vandercar , jewelers' use, tool for, l. g. grady , keg, lager beer, j. b. hayden , knitting machines, feed mechanism for circular, h. clarke , knob attachment, w. h. gonne , ladder, c. d. cannon , lantern holder, p. g. stephenson , lathe, gauge, f. w. clough , life preserver, c. d. oatman , lightning guard for oil tanks, a. a. knudson , limb, artificial, a. a. marks , lock, a. lemke , lock cylinder, h. r. towne , loom. a. l. & c. l. bigsby , lubricating apparatus, automatic, g. w. baker , machine brake, automatic, e. pitman , magnet, relay or sounder, g. little , malt, compressed, prendergast & free , marble, etc., composition for cleaning, g. p. cole , meat cutter, r. hübner. , meat cutting machine, l. steigert , mercurial fumes, apparatus for condensing, t. w. dresser , metals from their ores, machine for separating precious, g. hall , mirror hanger, c. w. prescott , moulding machines, apparatus for turning cutters for, l. wenchel , mower, lawn, h. g. fiske , musical string instruments, key for, j. singer , needle wrapper, j. m. woodward , optometer, a. mayer , overalls, a. clement , overalls, l. h. wise , packing case, folding, w. h. yaxley , paint cans, machine for filling, w. m. shoemaker , pantaloons elevator, c. b. plympton , paper bag machine, o. e. davidson , paper cutting machine, j. m. jones , paper feeding machine, griffith & byrne , paper, machine for fringing, s. garrett , paper machine pulp screen, s. l. gould , paper pulp digesters, etc., slide valve gate for, j. saunders , paper pulp pail, e. hubbard , paner tool, h. dewey , planter, check row seed, g. w. fink , planter, corn, wickey & brown , planter, cotton seed, j. h. walker , plow and seed planter, combined, sapp & mantz , plow, sulky, w. h. ryer , plumbers' traps, machine for making, f. n. du bois , pocket, s. marcus , pocketbook, h. j. lehman , portable engine boiler, d. m. swain. , preparations melting under ° fahrenheit, apparatus therefor, and their application, s. h. rouart , preserving animal and vegetable substances, compound for, j. hauff , pressure regulator, fluid, n. c. locke (r) , printing machines, stretching and drying apparatus for calico, f. j. crowley , printing presses, traversing inking roller for, a. shedlock , propelling vessels, mechanism for, b. palmer , pulley attachment, f. a. kittell , pump, p. e. jay , pump, l. m. canavel , pump, air, w. auteurietti , pump bucket, chain, laraway & rockwell , pump, diaphragm ship's, j. edson , pump, steam, e. e. miller , radiator, steam, h. mooers , railway chair, j. h. collingwood , railway fish plate, w. butcher , railway signal, pneumatic, j. a. emery , railway signaling apparatus, f. j. wenker , railway switch, t. solt , railway time signal, h. a. wayne , refrigerator, s. b. clemmens , riddle and sieve, e. oliver , roofing and paving material, c. m. warren , roofing composition, c. f. pearson , rudders, raising and lowering ships', r. f. loper, jr. , saccharine substances, treatment and preparation of, m. weinrich , , , sash fastening, burgess & sanford , seed huller, cotton, s. kitchens, sr. , sewing machine, koch & wiese , sewing machine, e. t. thomas , sewing machine, boot and shoe, e. woodward , sewing machine, button hole, j. h. applegate , sewing machine quilting gauge, j. h. lavance , sewing machine treadle, r. steel , seeding machines, spring hoe attachment for, s. b. hart , shirt, c. a. gilbert , sink outlet cover, j. w. grows , skate, roller, m. c. henley , smoke and gas consuming furnace, w. c. p. bissell , snow scraping machine, g. b. gruman , soda water and other liquids, apparatus for cooling, a. d. puffer (r) , soldering irons, rotary benzine furnace for heating, g. h. perkins , sole edge burnishing machine, tayman & bennor , spinning frames, mechanism for supporting the spindles of ring, j. birkenhead , spout, sap, i. h. spelman , steam pipes, etc., covering for, j. merriam , steam trap, j. h. blessing , stencil, d. w. ream , stereotype matrices, drying, w. j. johnson , stove, gasoline, w. c. north , stove grate, g. froh (r) , stove pipe shelf, s. ayres , stoves, portable extension top for, j. h. hutchinson , string instruments, key for tuning, j. singer , telegraph, duplex. a. muirhead , telephone, j. h. irwin , telephone, speaking, s. d. field , telephone system, g. d'infreville , thill coupling, p. klipple , thill coupling. l. b. lathrop , thrashing or hulling cylinder, j. i. mcclung , thread cutter, m. d. barringer , tinned metal plates by heat and pressure, automatic apparatus for uniting, g. h. perkins , tobacco curing apparatus, a. gordon , tobacco leaves, apparatus for coloring, j. m. henningsen , tobacco, marking plug, w. painter , toilet case, c. carroll , tongue hound for wagons, r. w. mcclelland , tongue support, wagon. g. f. wingate , tool shank, a. h. suplee (r) , toothpick, e. osgood , toy horse and wagon, f. w. carpenter , toy money bank, c. a. bailey , truck. e. j. leyburn , trucks, rub iron for car, d. e. small , valve, j. p. hillard , valve, balanced, moore & pertz , vehicle bow trimming, h. higgin , vehicle sand band, j. hitchcock , vehicle seat, f. oppenheim (r) , vehicle spring, g. e. harris , vehicle wheel, j. ladner , vehicle wheel, c. h. triphagen , wagon brake, whitman & igon , wagon brake shoe, c. a. skene , washing machine, j. g. crawford , washing machine, l. sternberger , watch, acoustic, g. a. bowen , watch case, w. calame , watches, roller abstractor for, b. frese (r) , water closet, s. s. hellyer , water elevator, j. r. cluxton , wells, drilling machine for artesian and oil, f. knowlan , whiffletree hook, c. wright , wind wheel, j. sander , windmill, coriell & adams , windmill, w. c. jacob , wood, ornamenting, pruyn & hyatt , wood turning machine, f. hanson , wrench and screw driver, comb'd, j. k. collins , * * * * * designs. coffin screw, e. a. cuppers , gem setting, vennin & peltier , lamp bracket, f. r. seidensticker , stove, cooking, h. l. fennell , type, font of printing, j. k. rogers , * * * * * trade marks. fish, manufactured, ferguson, walker & co , hats, gentlemen's and boys' and ladies' and misses' soft felt, topping maynard & hobron , tobacco, plug, g. wittler , jewelry, comprising lace pins, scarf pins, earrings, ear drops, brooches studs, sleeve buttons, and scarf rings. howard & scherrieble , soap, j. oakley & co. , tobacco, smoking and chewing, wilson & mccallay , , , yarn, cotton and woolen darning, h. c. conkle , * * * * * advertisements. inside page, each insertion-- cents a line. back page, each insertion--$ . a line. _engravings may head advertisements at the same rate per line, by measurement, as the letter press. advertisements must be received at publication office as early as thursday morning to appear in next issue._ the publishers of this paper guarantee to advertisers a circulation of not less than , copies every weekly issue. * * * * * a splendid holiday gift. dr. scott's electric hair brush. a remarkable invention, which has won its way to royal favor in england, been cordially indorsed by the prince and princess of wales, and written upon by the rt. hon. w. e. gladstone, is now brought to the notice of the american public. it cures by natural means, will always do good, never harm, and is a remedy lasting for many years. it should be used daily in place of the ordinary hair brush. the brush handle is made of a new odorless composition resembling ebony; a combination of substances producing a permanent electric voltaic current which acts immediately upon the hair glands and follicles. this power can always be tested by a silver compass which accompanies each brush. it is warranted to cure nervous headache in minutes!!! cure neuralgia in minutes!! prevent falling hair and baldness!! cure dandruff & diseases of the scalp!! promptly arrests premature grayness!! makes the hair grow long & glossy!! immediately soothes the weary brain money returned if not as represented. it rarely fails to produce a rapid growth of hair on bald heads, where the glands and follicles are not totally destroyed. proprietors: the pall mall electric association of london. th new york branch: broadway. [from the mayor of saratoga.] august , . "i cheerfully testify to the merits of dr. scott's electric hair brush. it cures my headaches within a few minutes. i am so pleased with it i purchased another for my wife. it is an excellent hair brush, well worth the price, aside from its curative powers." jas. b. chapman. [from rev. dr. bridgeman.] brooklyn, june st, . "gents: i have never before given a testimonial, but am willing to encourage the use of an honest remedy. i am so pleased with your hair brush that i deem it my duty to write you recommending it most cordially. my hair, about a year since, commenced falling out, and i was rapidly becoming bald; but since using the brush a thick growth of hair has made its appearance, quite equal to that which i had previous to its falling out. i have tried other remedies, but with no success. after this remarkable result i purchased one for my wife, who has been a great sufferer from headache, and she finds it a prompt and infallible remedy." a. c. bridgeman, d. d. [illustration] pulton street, new york, august , . "i would not take $ , for my brush if i could not replace it." pliny f. smith. mr. smith is a gentleman well known in this city as a law publisher, and also as a director in several public institutions of new york. "domestic" sewing machine co., new york, august , . dr. geo. a. scott--dear sir: permit me to add the testimony of my wife to that of the many others who have been benefited by the use of your electric brush. she has for years been a sufferer from neuralgia in an acute form, but since i obtained for her one of your brushes, she has experienced entire relief. please accept her sincere thanks.--henry bartlett. round lake camp-meeting grounds, saratoga co., n. y., june , . your brush is certainly a remarkable cure. i am highly pleased with it. its effect is most wonderful, and you may be sure i shall recommend it heartily among my friends. it is also a splendid hair brush, well worth the money, and will last me for years.--rev. j. d. rogers, superintendent. mention this paper. over , similar testimonials can be seen at our office. remember that this is not a "metallic" wire brush, but made of pure bristles. a beautiful brush, lasting for years. we will send it, postpaid, on receipt of $ . ; or by express c. o. d. at your expense, with privilege of opening and examining. or request your nearest druggist or fancy store to obtain one for you, from us. money returned if not as represented. as soon as you receive the brush, if not well satisfied with your bargain, write us, and we will return the money. what can be fairer? this paper will not knowingly publish any humbug, and i have placed a brush in the hands of mayor cooper and postmaster james of new york, as a guarantee of my good faith. up remittances should be made payable to geo. a. scott, a broadway, new york. agents wanted in every town. they can be made in checks, drafts, post office orders, or currency. inclose cents for registration, and we guarantee safe delivery of brush. * * * * * the swiss warbler or mocking-bird whistle it imitates every sound in the animal kingdom from the thrill of the nightingale to the howl of the wolf after a little practice your mouth will seem to be a complete menagerie you can raise a laugh or pierceing cry of horror at pleasure. sample by mail, only cts., for cts., for cts. valuable catalogue of agent's goods free. world manufacturing co., nassau street, new york. * * * * * steam boilers; their design, construction, and management. by william m. shock, chief of bureau of steam engineering, united states navy. in one large quarto volume of pages, and illustrated with wood-cuts and full-page plates ( of which are double). bound in half crimson morocco, gilt tops. price $ d. van nostrand. publisher, murray and warren sts., new york. *** copies sent by mail, postpaid, on receipt of price. * * * * * the holly system of steam heating for cities and villages, holly steam combination co. limited lockport, n. y. see illustrated ad in last number * * * * * toope's pat. felt and asbestos non-conducting, removable covering, as manufactured by toope's asbestos covering co., limited, london, england. awarded a medal of excellence at the late american institute fair. for steam boilers and pipes, steam pans and coppers, hot and cold water pipes, refrigerators, meat cars, etc. samples free. a few first-class agents wanted. address chs. toope, sole manufacturing agent in u. s. office and works, east th street, new york city. * * * * * agents wanted sells rapidly. particulars _free_. s. m. spencer, wash'n st., boston, mass. * * * * * for sale-large machine shop, with machinery, tools, engine, etc., _ready for running_. inquire of a. monnett & co., bucyrus, ohio. * * * * * a elegant, all new, chromo & scroll cards, no alike, name nicely printed, c. card mills, morthford, ct. * * * * * [illustration] patent bending rolls, for heavy punches, shears, boiler shop rolls, radial drills, etc., send to hilles & jones, wilmington, del. * * * * * no more use for oil on machinery oline lubricating compound, manuf'd by holland & thompson, troy, n. y. avoids hot journals, dripping, and waste. send for catalogue of grease and cups for all kinds of machinery. * * * * * plays! plays! plays! plays! for reading clubs, for amateur theatricals, temperance plays, drawing room plays, fairy plays, ethiopian plays, guide books, speakers, pantomimes, tableaux lights, magnesium lights, colored fire, burnt cork, theatrical face preparations, jarley's wax works, wigs, beards, and moustaches at reduced prices. costumes, scenery, charades. new catalogues sent free containing full description and prices. samuel french & son, e. th street, new york. * * * * * ice and ice houses--how to make ice ponds; amount of ice required, etc., and full directions for building ice-house, with illustrated plan. contained in scientific american supplement, no. . price cents. to be had at this office and of all newsdealers. * * * * * [illustration] the new toy! old folks tickled and children delighted mechanical grasshopper, jumps feet high. samples free for cents, for cents, doz. for cts. by mail. big profit to dealers. agents wanted. valuable catalogue of agents goods free. address, world m'f'g, co. nassau st., new york. * * * * * chromos, name in new type, c. by mail. _ agts. samples_, c. u. s. card co., northford, ct. * * * * * wanted, by the southwark foundry and machine co., philadelphia, a number of first-class fitters on engine work. * * * * * ice-house and cold room.--by r. g. hatfield. with directions for construction. four engravings. contained in scientific american supplement, . price cents. to be had at this office and of all newsdealers. * * * * * for sale.--engine for steam launch, at a bargain. cylinder, ½ in. diameter, in. stroke. for particulars, address james t. miller, monroe st., chicago, ill. * * * * * [illustration] langdon mitre box co, millers falls mass. langdon and new langdon mitre box. send for circular. * * * * * scientific american supplement. any desired back number of the scientific american supplement can be had at this office for cents. also to be had of newsdealers in all parts of the country. * * * * * the open fireplace in all ages. by j. p. putnam, architect. one vol. mo. price $ . with illustrations of famous fireplaces of historical and artistic interest, together with original designs and suggestions for modern use. *** for sale by all booksellers, or will be sent, postpaid, on receipt of price, by the publishers, james r. osgood & co., boston. * * * * * steam pumps, the norwalk iron works co., south norwalk, conn. * * * * * great improvements recently made in crushing and grinding gold and silver ores, bones, phosphate rock, and chemicals. we compel quartz to grind quartz. address, for new circular, baugh & sons, philadelphia, pa. * * * * * [illustration] best foot lathes, back geared and screw cutting. small lathes, hand planers for metal, small gear cutters, slide rests, scroll and circular saw machines. lowest prices. send for illustrated catalogue. n. h. baldwin, laconia, n. h. * * * * * mechanic wanted. a skilled mechanic, capable of constructing and operating a works for the manufacture of wrought iron pipe and tubing. address dunmoyle, lock box , pittsburg, pa. * * * * * centennial, and paris medals. mason's friction clutches and elevators. "new and improved patterns." volney w. mason & co., providence, r. i., u. s. a. * * * * * wanted a thoroughly competent and experienced man to take charge of a foundry employing men, doing engine and general work. address a. & co., box , new york. * * * * * blake's patent positive steam trap. [illustration] this trap is adapted to all places where steam is used for _heating_ or _drying_ purposes. it is simple in construction, _positive in its working_ and much lower in price than any other trap. descriptive circular sent on application. address salamander grate bar co, liberty street, new york. * * * * * the perfected stylografic little [illustration] giant the most convenient and economical outfit for writing. pen, pencil, and inkstand in one. writes large pages without refilling. lasts a lifetime. attaches to watch chain or neck cord, or fits vest pocket. price $ . . can be ordered by mail, and exchanged or returned if not suited. for full description of various styles, send for circular. readers' and writers' economy co., - franklin street, boston; bond street, new york; madison street, chicago. * * * * * phosphor-bronze wire, sheets, rods, bolts. [illustration] pamphlets and particulars on application to the phosphor-bronze smelting co. limited, washington ave., phila., pa. owners of the u s. phosphor-bronze patents. sole manufacturers of phosphor-bronze in the u. s. * * * * * magic lantern catalogue, pp, and lecture, cts. magic lanterns and views the magical organette, only $ . . double size reeds, extra strength and finish. circulars and beautiful set fancy cards, cents. theo. j. harbach, filbert st., phila., pa. * * * * * perkins' high pressure engine and boiler, etc. on returning to england, i have arranged with mr. james l. howard, of hartford, conn., to represent the interests of the perkins' engine company, limited, of london, in this country. all communications addressed to him on this subject will receive attention. geo. deane. secretary, the perkins' engine co., limited. * * * * * _lithographed_ chromo cards, no alike, c. name in fancy type. conn. card co., northford, ct. * * * * * do your own printing [illustration] presses and outfits from $ to $ over , styles of type. catalogue and reduced price list free. h. hoover, phila., pa. * * * * * strauss's last. the hektograph schnell polka pronounced by critics as unrivalled, the rage at balls and parties, sent on receipt of cts. hektograph co. pub's, church st., n. y. * * * * * toope's patent furnace grate bar. best and cheapest in the world. chs. toope, manufacturing agent, east th street, new york. * * * * * wanted manufactured on royalty, a valuable patented two-horse corn planter. box , terre haute, ind. * * * * * pond's tools, engine lathes, planers, drills, &c. david w. pond, worcester, mass. * * * * * [illustration] the great work, splendidly illustrated with colored plates, now ready. it sells at sight. agents wanted. send for particulars. rich masonic goods, kt. templar outfits, and books at hard-pan prices. send for illustrated catalogue. redding & co., masonic publishers, broadway, new york. beware of spurious works. * * * * * spare the croton and save the cost. driven or tube wells furnished to large consumers of croton and ridgewood water. wm. d. andrews & bro., broadway. n. y., who control the patent for green's american driven well. * * * * * wood working machinery. celebrated "schenck" planers and matchers. , ft. flooring, , ft. surfacing per day. re-sawers, moulders, tenoners, scroll saws, etc. h. b. schenck, successor to jno. b. schenck's sons, matteawan, n. y. * * * * * cary & moen steel wire of every description and steel springs. w. st. new york city * * * * * "the injector." simple, durable, and reliable. requires no special valves. send for illustrated circular. wm. sellers & co., phila. * * * * * shafts, pulleys, hangers, etc. full assortment in store for immediate delivery. wm. sellers & co., liberty street, new york. * * * * * _two new and important books._ soap and candles, starch, dextrine, and glucose. in press. a technical treatise on soap and candles, with a glance at the industry of fats and oils. by r. s. cristiani. fully illustrated. pages vo, handsomely printed on fine paper. _subscriptions will now be received at $ . per copy, payable on delivery._ a practical treatise on the manufacture of starch, dextrine, and glucose. illustrated by about engravings. pages vo, handsomely printed on fine paper. _subscriptions will now be received at $ . per copy, payable on delivery._ henry carey baird & co., industrial publishers, booksellers, and importers, walnut street, philadelphia. * * * * * [illustration] witherby, rugg & richardson, manufacturers of patent wood working machinery of every description. facilities unsurpassed. shop formerly occupied by r. ball & co., worcester, mass. send for catalogue. * * * * * $ a week. $ a day at home easily made. costly outfit free. address true & co., augusta, me. * * * * * superior wood working machinery, principally for cabinet, piano, and piano action makers. shafting, pulleys, and hangers. p. pryibil, to w. th st., new york. * * * * * surface file holders. by their use a crooked file may be utilized as well as a straight one, and _both_ are made to do better execution in filing broad surfaces than has hitherto been possible. no. holds files to in. long. price c. each. no. " " to in. " price $ . each. for sale by the trade generally. manufactured only by the nicholson file co., providence, r. i. * * * * * the biggest thing out. illustrated book sent free. address e. nason & co., nassau st., new york. * * * * * organs $ to $ , ; to stops. pianos $ up. paper free. address daniel f. beatty, washington, n. j. * * * * * [illustration] leffel water wheels, with recent improvements. prices greatly reduced. in successful operation. fine new pamphlet for , sent free to those interested. james leffel & co, springfield, o. liberty st., n. y. city. * * * * * three beautiful gift books for the holidays. "the dore bible gallery." containing one hundred of the choicest of gustave doré's illustrations of the bible, and a page of explanatory letter-press facing each engraving, together with a superb portrait of the artist. large quarto, cloth, full gilt, $ ; morocco, full gilt, $ . "atala" by m. de chateaubriand. an american story, and one of the best efforts of the celebrated author. superbly illustrated with numerous full pages of some of our grandest scenery, by gustave doré. printed on heavy tinted paper, and richly bound. large quarto, cloth, full gilt, $ ; morocco, full gilt, $ . "the wandering jew." a series of twelve illustrations by gustave doré, picturing the weird and unearthly scenes of the legend, with explanatory letter-press. large quarto, cloth, gilt, $ . . "a most beautiful production."--_brooklyn advance_. "published in very rich style."--_publishers' weekly_. "is meeting with deserved success."--_bookseller and stationer_. "such books are educators in the highest sense of the term."--_chicago inter-ocean_. "one of the most successful productions that have done honor to the pencil of gustave doré."--_providence journal_. "contains some of the most striking productions of doré at a moderate cost."--_n. y. tribune_. "we are very glad they have been put within the reach of the many."--_hartford courant_. the fine art publishing co., pearl street, new york. for sale by all booksellers, or sent, postpaid, on receipt of price, by the publishers. * * * * * sash dovetailing machine. [illustration] planers, moulding machines, mortisers and borers, tenoning machines, blind rabbeting machines; also, a large variety of other wood working machines, manufactured by levi houston, montgomery, pa. * * * * * telephone works mile. price $ . pat'd. circulars free. holcomb & co., mallet creek, ohio. * * * * * agents wanted to introduce a new and novel account book to business men. a rich harvest to competent parties during the next three months. all particulars by return mail. h. w. pamphilon, bond st., new york city. * * * * * $ to $ per day at home. samples worth $ free. address stinson & co., portland, me. * * * * * catalogue of novelties for agents free. j. f. gage, boston, mass. * * * * * ericsson's new motor. ericsson's new caloric pumping engine, for dwellings and country seats. simplest cheapest, and most economical pumping engine for domestic purposes. any servant girl can operate. absolutely safe. send for circulars and price lists. delamater iron works c. h. delamater & co., proprietors, no. cortlandt street, new york, n. y. * * * * * superior substitute for wood engraving. _j. c. moss, pres. and sup't._ _r. b. moss, assist. sup't._ _m. a. moss, treasurer._ _j. e. ramsey, secretary._ _h. a. jackson, assist. sec._ moss engraving co incorporated (moss's new process.) april , pearl street, cor. elm, new york. largest establishment of the kind in the world. engravings of portraits, buildings, landscapes, machinery, maps, ornamental lettering and general illustrations for newspapers, books, catalogues, etc. much cheaper than wood cuts. _mr. j. c. moss, the inventor of the moss process of photo-engraving, in withdrawing from the photo-engraving co., park place, has retained for himself all improvements made and used by him in photo-engraving since may, ._ send green stamp for illustrated circular. send copy for estimate. please mention this paper. * * * * * [illustration] the blake "lion and eagle" crusher, a patented improvement of the former "new pattern" blake machine. has much greater efficiency than the old. it requires only about half the power to drive, and is transported at much less expense (the size most used weighing several thousand pounds less than the unimproved machine). it requires less than half the time in oiling and other manipulation, and less than half the expense for repairs. address e. s. blake & co., pittsburgh, pa., sole proprietors and manufacturers. [illustration] * * * * * [illustration] w. c. wren's pat. grate bar, manufactured by d. & s. creswell, eagle iron foundry, race st., philadelphia, pa. * * * * * [illustration] rock breakers & ore crushers. (the "blake" style.) this machine has for twenty years stood the test, and found to be the _best one_ made for breaking all kinds of hard and brittle substances, such as ores, quartz, emery, etc., etc. mr. s. l. marsden, for the past twenty years connected with the manufacture of this machine, superintends its manufacture. farrel foundry and machine co., manufrs., ausonia, conn. * * * * * the melodette, or automatic piano, [illustration] the most marvellous mechanical invention of the age. it will play any tune that ever was written, in a melodious and pleasing manner. difficult and simple music produced in a masterly style, and it can be played by a child as well as by a grown person, and will furnish music for social gatherings of any description, playing hour after hour, without any knowledge of music being required in the operation. the most wonderful of all musical inventions; a machine which in a purely mechanical manner produces any kind of music, waltzes, polkas, marches, &c., &c., without any practice or knowledge of music whatever; in this respect far superior to any music-box, even though it costs many times as much, for there is no limit whatever to the number of tunes it will play. this instrument is on a somewhat similar principle to the wonderful phonograph, the perforations in a flexible strip producing the effect. it has just been perfected (the accompanying cut showing it in its improved form), and is having the largest sale ever obtained by a musical instrument in the country. it has solid metal cases in imitation of green bronze; the notes or bars (the music producers) are metal, on same principle as a tuning-fork, which produce clear and most melodious notes, and never get out of tune; the bars are struck by strikers, the same as the wires are in a piano, only they work automatically instead of by the fingers. the strip of prepared paper in which the tune is stamped or perforated, is about inches wide, and as it passes through the rollers and over the keys the strikers spring through the perforations in the paper and strike the right note; this is all done automatically, without any assistance from the operator (except turning the rollers), and the tune is played perfectly. it would be one of the most appropriate presents to make anyone, especially where there is no other musical instrument. its execution is admirable, and its capacity or capability almost unlimited. it is selling faster than any musical instrument ever invented. the music is fine, and everybody delighted. the regular retail price of the melodette is only $ , including a selection of popular tunes. address, the massachusetts organ co., washington street boston, mass., u. s. a., sole manufacturers. special offer--agents wanted--we wish a good agent in every town, and big money can be made selling these instruments. we will send a sample instrument to any one wishing to act as our agent, for $ . , boxed free, including music price lists, etc., etc., and will give territory. order at once. $ a week easily made. _we have testimonials_. * * * * * rubber back square packing. best in the world. [illustration] for packing the piston rods and valve stems of steam engines and pumps. b represents that part of the packing which, when in use, is in contact with the piston rod. a the elastic back, which keeps the part b against the rod with sufficient pressure to be steam-tight, and yet creates but little friction. this packing is made in lengths of about feet, and of all sizes from ¼ to inches square. john h. cheever, treas. new york belting & packing co., & park row, new york. * * * * * [illustration] the stearns manufacturing co., erie, pennsylvania, make a specialty of improved saw mill machinery. designed in its construction for producing lumber economically and rapidly. plans and estimates for mills of any capacity furnished on request. also build engines, boilers, and machinery in general. * * * * * [illustration] forster's rock & ore breaker and combined crusher and pulverizer. _the simplest machine ever devised for the purpose._ parties who have used it constantly for six years testify that it will do _double_ the work of _any other crusher_, with one-third the power, and one-half the expense for keeping in repair. the smaller sizes can be run with horse power. address totten & co., pittsburgh, pa. * * * * * the belmontyle oil prevents rust, tarnish, etc., on firearms, machinery, tools, cutlery, safes, saws, skates, stoves, hardware, etc., without injury to the polish. in use over years. highest testimonials. samples cents, three for $ . , sent free of expressage. send for circular. belmontyle oil co., sole manufacturers, front street, new york. * * * * * carnegie bros & co union iron mills pittsburgh pa wrought iron beams channels tees & angles the attention of architects, engineers, and builders is called to the great decline in prices of wrought structural iron. it is believed that, were owners fully aware of the small difference in cost which now exists between iron and wood, the former, in many cases, would be adopted, thereby saving _insurance_ and avoiding all risk of _interruption_ to _business_ in consequence of fire. book of detailed information furnished to architects, engineers, and builders, on application. * * * * * [illustration] microscopes, telescopes, field glasses, magic lanterns, aneroid barometers, spectroscopes, drawing instruments, philosophical & chemical apparatus. catalogues as follows sent on application: part , mathematical instruments, pp.; part , optical instruments, pp.; part , magic lanterns, pp.; part , philosophical and chemical apparatus, pp. james w. queen & co. chestnut st., philadelphia, pa. * * * * * "reliable" engines a complete success. prices still per cent. below those of other makers. unequaled for efficiency, simplicity, and durability. prices from $ for h. p., to $ for h. p. all complete, with governor, pump, and heater. address, for circular, heald, sisco & co., baldwinsville, n. y. * * * * * universal grinder. these grinders consist of a series of disks with beveled edges locked together on a shaft. they revolve towards each other at different rates of speed. they combine strength and durability. no friction; hence no heat. they will grind all kinds of grain, also quartz rocks, ores, gypsum, brimstone shavings, shells, brick clay, cork, rubber, bone, oil cake, flax seed, cotton seed, and any number of articles in use by manufacturers and farmers. these grinders are disposed of on reasonable terms. send for illustrated catalogue with terms. newell & chapin, foot of west th street, new york. * * * * * [illustration] sizes of direct, sizes of boilers, and the best indirect radiation. send for circulars. eureka steam heating co. rochester, n. y. * * * * * otis' safety hoisting machinery. otis bros. & co., no. broadway, new york. * * * * * john r. whitley & co. european representatives of american houses, with first-class agents in the principal industrial and agricultural centers and cities in europe. london, poultry, e. c. paris. place vendême. terms on application. j. r. w. & co. purchase paris goods on commission at shippers' discounts. * * * * * roots' new iron blower. [illustration] positive blast. iron revolvers, perfectly balanced is simpler, and has fewer parts than any other blower. p. h. & f. m. roots, manuf'rs, connersville, ind. s. s. townsend, gen. agt., cortlandt st., dey street, new york. wm. cooke, selling agt., cortlandt street, new york. jas. beggs & co., selling agts., dey street, new york. send for priced catalogue. * * * * * proposals for mail locks. post office department, washington. d. c., october , . sealed proposals will be received at this department, until o'clock, noon, on the th day of january, , for furnishing a new kind of mail locks and keys for the sole and exclusive use of the united states through registered mails. as the public exposure and searching examination necessary to intelligent bidding on any prescribed model of a lock and key would tend to impair, if not entirely destroy, the further utility of such locks and keys for the purposes of the mails, the postmaster general prescribes no model or sample for bidders, but relies for a selection on the mechanical skill and ingenuity which a fair competition among inventors, hereby invited, may develop in samples submitted by them. specifications of the conditions and requirements relating to proposals, samples, contract, etc., as well as forms of proposal, will be furnished on application by letter to the second assistant postmaster general. no proposal will be considered unless it shall have been submitted in accordance with such specification and forms. the contracts which may be made will be in conformity to the specifications and the accepted proposal. but the right is, however, reserved to reject any and all of the proposals. jas. n. tyner, acting postmaster general. * * * * * shepard's celebrated $ screw cutting foot lathe. [illustration] foot and power lathes, drill presses, scrolls, circular and band saws, saw attachments, chucks, mandrels, twist drills, dogs, calipers, etc. send for catalogue of outfits for amateurs or artisans. h. l. shepard & co., , , , & west front street, cincinnati, ohio. * * * * * hub machinery.--hub turning, hub mortising, and hub boring machines. send for price list and circulars. david jenkins, sheboygan, wis. * * * * * roofing. for steep or flat roofs. applied by ordinary workmen at one-third the cost of tin. circulars and samples free. agents wanted. t. new, john street, new york. * * * * * patent cold rolled shafting. the fact that this shafting has per cent. greater strength, a finer finish, and is truer to gauge, than any other in use renders it undoubtedly the most economical. we are also the sole manufacturers of the celebrated collins' pat. coupling, and furnish pulleys, hangers, etc., of the most approved styles. price list mailed on application to jones & laughlins, try street, d and d avenues, pittsburg, pa. s. canal street, chicago, ill. stocks of this shafting in store and for sale by fuller, dana & fitz, boston, mass. geo. place machinery agency, chambers st., n. y. * * * * * model engines. [illustration] complete sets of castings for making small model steam engines ½ in. bore, in. stroke, price,$ ; ditto in. bore, in. stroke, price, $ , same style as cut. gear wheels and parts of models. all kinds of small tools and materials. catalogue free. goodnow & wightman, washington street, boston, mass. * * * * * send for the best band saw blade in the market to london, berry & orton, phila., pa. * * * * * coe brass mfg. co. wolcottville conn. brass and copper in sheets. wire and blanks materials for metallic. ammunition a specialty. * * * * * machinists' tools. new and improved patterns. send for new illustrated catalogue. lathes, planers, drills, &c. new haven manufacturing co., new haven, conn. * * * * * skates and novelties. send for catalogue. r. simpson, nassau st., n. y. * * * * * porter manuf'g co. [illustration] the new economizer, the only agricultural engine with return flue boiler in use. send for circular to porter mfg. co., limited, syracuse. n. y. [illustration] g. g. young, gen. agt., cortland st., new york. * * * * * advertisements. inside page, each insertion-- cents a line. back page, each insertion--$ . a line. (about eight words to a line.) _engravings may head advertisements at the same rate per line, by measurement, as the letter press. advertisements must be received at publication office as early as thursday morning to appear in next issue._ the publishers of this paper guarantee to advertisers a circulation of not less than , copies every weekly issue. * * * * * the wonderful christmas "st. nicholas." a special holiday number, designed for boys and girls everywhere, whether regular readers of the magazine or not;--the best, and, by reason of its immense edition, , , the cheapest christmas book published, price cents. a brilliant holiday cover; superb pictures by the best american artists; a capital acting operetta for children "the land of nod," with words and music; a splendid story by washington gladden, "a christmas dinner with the man in the moon," the illustrations of which rival dore's; "king arthur and his knights," by sidney lanier; one of frank r. stockton's inimitable fairy stories; the "treasure box of literature," etc., etc.;--in all, thirty-three departments and contributions. a grand holiday gift-book of pages, printed on tinted paper, illustrated with scores of charming pictures, for only cents. ask for the christmas (december) st. nicholas. four editions of last year's holiday number were demanded. for sale everywhere. subscription price, $ . per year. scribner & co., broadway, n. y. * * * * * $ present! for a machine that will saw as fast and easy as this one. [illustration] this is the king of saw machines. it saws off a foot log in minutes. , in use. the cheapest machine made, and fully warranted. circular free. united states manufacturing co., chicago, ill. * * * * * the new york belting and packing company look for our stamp on the goods whenever you buy belting, hose, or packing. & park row, new york. * * * * * [illustration] watchman's improved time detector, with safety lock attachment, patented - - . beware of infringements. this instrument is supplied with keys for different stations. invaluable for all concerns employing night watchmen. send for circulars to e. imhauser, p. o. box . broadway, new york. * * * * * mill stones and corn mills. we make burr millstones, portable mills, smut machines, packers, mill picks, water wheels, pulleys, and gearing specially adapted to flour mills. send for catalogue. j. t. noye & sons, buffalo, n. y. * * * * * the new pulsometer is more economical in points of original cost, expense for repairs and running expenses, than any other steam pump in the world. [illustration] simple and compact, with no machinery whatever to oil, or get out of order, it stands at the head of all means of elevating water or other liquids by steam. _it needs no skilled labor to look after it._ send for book giving full description, reduced prices and many letters of commendation from leading manufacturers and others throughout the country who are using them. pulsometer steam pump co., sole owners of hall's patents in the u. s., , to , , both inclusive, and the new pulsometer, office, no. john st., p.o. box no. . new york city. * * * * * pictet artificial ice co., limited, p.o. box greenwich st., new york. guaranteed to be the most _efficient_ and _economical_ of all existing ice and cold air machines. * * * * * h.w. johns' asbestos liquid paints, roofing, steam pipe & boiler coverings, steam packing, mill board, sheathing, fire proof coatings, &c. send for descriptive price list. h. w. johns m'f'g co. maiden lane, n. y. * * * * * $ a week in your own town. terms and $ outfit free. address h. hallett & co., portland, me. * * * * * the george place machinery agency machinery of every description. chambers and beade streets, new york. * * * * * emery wheels and grinding machines. [illustration: ex inutili trade tanite mark utilitas] the tanite co., stroudsburg, monroe comity, pa. orders may be directed to us at any of the following addresses, at each of which we carry a stock: new york, dey street. chicago, and lake st. st. louis, north third st. st. louis, to north second st. cincinnati. west second st. louisville, west main st. indianapolis, corner maryland and delaware sts. new orleans, union st. san francisco, and california st. philadelphia, north sixth street. boston, doane st. portland, oregon, front st. london. eng., st. andrews st., holborn viaduct, e. c. liverpool, eng., the temple, dale st. sydney, n. s. w., pitt st. * * * * * _before ordering engraving of any kind, send to us for estimates and samples. we have the largest engraving establishment in the world, and the best facilities for doing work of the best quality, quickly and cheaply._ _photo-engraving co. & park place, new york._ * * * * * hartford steam boiler inspection & insurance company w. b. franklin, v. pres't, j. m. allen, pres't. j. b. pierce, sec'y. * * * * * columbia bicycle. [illustration] the bicycle has proved itself to be a permanent, practical road vehicle, and the number in daily use is rapidly increasing. professional and business men, seekers after health or pleasure, all join in bearing witness to its merits. send cent stamp for catalogue with price list and full information. the pope m'f'g co., summer street, boston, mass. * * * * * agents can make $ , . by securing the manufacturers' cabinet. by employing agents for manufacturers. by manufacturing rapid selling articles. by getting, through means of the cabinet, the best agencies in the world. address j. b. chapman, west st., madison, ind. * * * * * telephone and electrical supplies send for catalogue. c. e. jones & bro., cincinnati, o. * * * * * steam fitters' & plumbers' supplies. sturtevants' fan blowers. albert bridges, cortlandt street, new york. * * * * * pumping, piston rod, plunger & well the watson pump, for artesian, or deep well rod in direct line machine simple, efficient. james watson s. front st. phila. * * * * * boiler coverings. plastic cement and hair felt, with or without the patent "air space" method. asbestos materials. made from pure italian asbestos in fiber mill board and round packing. the chalmers-spence co., john street, and foot of e. th street, new york. * * * * * perfectly smooth thoroughly seasoned cut thin lumber!! manufactured by our patent board cutting machines and seasoning presses. pronounced the only perfect cut lumber!! mahogany, rosewood, satinwood, walnut, ash, red cedar, cherry, oak, poplar, maple, holly, french walnut, etc., etc.. in logs, planks, boards, and veneers. send for catalogue and price lists. geo. w. read & co., to lewis st. foot th and th sts., new york. * * * * * [illustration] snow's best water wheel governor, manufactured by cohoes iron foundry and machine, co., cohoes, n.y. * * * * * $ . agents' profit per week. will prove it or forfeit $ . . outfit and samples worth $ . free. address e. g. rideout & co., barclay street, new york. * * * * * steel castings from ¼ to , lb. weight, true to pattern, of unequaled strength, toughness, and durability. , crank shafts and , gear wheels of this steel now running prove its superiority over other steel castings. send for circular and price list. chester steel castings co., library st., phila, pa. * * * * * pyrometers. for showing heat of ovens, hot blast pipes, boiler flues superheated steam, oil stills, etc. henry w. bulkley, sole manufacturer, broadway, n.y. * * * * * wm. a. harris providence, r. j. (park street), six minutes walk west from station. original and only builder of the harris-corliss engine with harris' patented improvements, from to , h. p. * * * * * shafts pulleys hangers at low prices. large assorted stock. a. & f. brown, - lewis st., new york. * * * * * [illustration] the baker blower, centennial judges report. "good design and material. very efficient in action. with the special advantages that they can be connected for motion directly with engine without the use of gearing or belting." send for catalogue. wilbraham bros. no. frankford avenue, philadelphia, pa. * * * * * microscopes, opera glasses, spy glasses, spectacles, thermometers, barometers, compasses. r. & j. beck, manufacturing opticians. philadelphia, pa. send for illustrated priced catalogue. * * * * * the oldest yankee notion house in the world. howard brothers & read, successors to howard, sanger & co., owners of the howard manufacturing co., manufacture and introduce patented novelties. [illustration] the only real pocket scale in the market. made of metal, heavily nickel plated, compact, strong, durable. can be carried in the vest pocket. each one warranted absolutely accurate. weighs up to lbs. price cents. sample by mail on receipt of price. a liberal discount to the trade. no. --"post office," weighs to ozs. " --"pocket," weighs to lbs. howard manufacturing co., box , new york. * * * * * bogardus' patent universal eccentric mills--for grinding bones, ores, sand, old crucibles, fire clay, guanos, oil cake, feed, corn, corn and cob, tobacco, snuff, sugar, salts, roots, spices, coffee, cocoanut, flaxseed, asbestos, mica etc., and whatever cannot be ground by other mills, also for paints, printers' inks, paste blacking, etc. john w. thomson, successor to james bogardus, corner of white and elm sts., new york. * * * * * the new york ice machine company, courtland st., new york, booms , . low pressure binary absorption system machines making ice and cold air. low pressure when running. no pressure at rest. machines guaranteed by c. h. delamater & co. * * * * * [illustration] our new stylographic pen (just patented), having the duplex interchangeable point section, is the very latest improvement. the stylographic pen co., room , broadway, new york. send for circular. * * * * * knabe pianofortes. unequaled in tone, touch, workmanship, & durability. warerooms fifth avenue. new york. & w. baltimore st., baltimore. * * * * * non-conductor coverings, _for steam boilers and pipes._ the raymond m'f'g co., west d st., liberty st., new york. * * * * * power shears. stiles & parker press co., middletown, conn. * * * * * [illustration] do your own printing $ press prints &c. (self-inker $ ) larger sizes for larger work. for old or young. great money saver. a paying business anywhere for all or spare time. send two stamps for a catalogue of all sizes. presses, type, cards, paper &c., to the manufacturers kelsey & co., meriden, conn. * * * * * the asbestos packing co., miners and manufacturers of asbestos, boston, mass., offer for sale: patented asbestos rope packing, " " loose " " " journal " " " wick " " " mill board, " " sheathing paper, " " flooring felt, " " cloth. * * * * * prospectus of the scientific american for . the most popular scientific paper in the world. volume xliv. new series. only $ . a year, including postage. weekly, numbers a year. this widely circulated and splendidly illustrated paper is published weekly. every number contains sixteen pages of useful information, and a large number of original engravings of new inventions and discoveries, representing engineering works, steam machinery, new inventions, novelties in mechanics, manufactures, chemistry, electricity, telegraphy, photography, architecture, agriculture, horticulture, natural history, etc. all classes of readers find in the scientific american a popular _resume_ of the best scientific information of the day; and it is the aim of the publishers to present it in an attractive form, avoiding as much as possible abstruse terms. to every intelligent mind, this journal affords a constant supply of instructive reading. it is promotive of knowledge and progress in every community where it circulates. terms of subscription.--one copy of the scientific american will be sent for _one year_-- numbers--postage prepaid, to any subscriber in the united states or canada, on receipt of three dollars and twenty cents by the publishers; six months, $ . ; three months, $ . . clubs.--one extra copy of the scientific american will be supplied gratis _for every club of five subscribers_ at $ . each; additional copies at same proportionate rate. one copy of the scientific american and one copy of the scientific american supplement will be sent for one year, postage prepaid, to any subscriber in the united states or canada, on receipt of seven dollars by the publishers. the safest way to remit is by postal order, draft, or express. money carefully placed inside of envelopes, securely sealed, and correctly addressed, seldom goes astray, but is at the sender's risk. address all letters and make all orders, drafts, etc., payable to munn & co., park row, new york. to foreign subscribers.--under the facilities of the postal union, the scientific american is now sent by post direct from new york, with regularity, to subscribers in great britain, india, australia, and all other british colonies; to france, austria, belgium, germany, russia, and all other european states; japan, brazil, mexico, and all states of central and south america. terms, when sent to foreign countries, canada excepted, $ , gold, for scientific american, year; $ , gold, for both scientific american and supplement for year. this includes postage, which we pay. remit by postal order or draft to order of munn & co., park row, new york. * * * * * the "scientific american" is printed with chas. eneu johnson & co.'s ink. tenth and lombard sts., philadelphia, and gold st. new york. [illustration] scientific american supplement no. new york, april , scientific american supplement. vol. xix, no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. chemistry and metallurgy.--the determination of graphite in minerals.--by j.b. mackintosh. sulphocyanide of potassium. sugar nitro-glycerine. on remelting of cast iron. the hardness of metals. ii. engineering, etc.--the jet ventilator. figures. feeding boilers at the bottom. figures. the honigmann fireless engine.--the fireless working of steam engines by means of a solution of hydrate of soda.--with several figures and diagrams. simple methods of calculating stress in girders.--by ch. lean.--with full page of illustrations. a spring motor. steam yachts. iii. technology.--foucault's apparatus for manufacturing illuminating gas and hydrogen. figures. the circle divider. soluble glass.--process of manufacture.--use. iron printing and microscopic photography.--formulas for printing solutions.--compound negatives. practical directions for making lantern transparencies.--by t.n. armstrong. casting chilled car wheels. figures. iv. electricity, etc.--electricity and prestidigitation. figures. portable electric safety lamp. figures. the electric discharge and spark photographed directly without an objective. engravings. v. physics, etc.--the true constant of gravity. origin of thunder storms. physics without apparatus.--manufacture of illuminating gas.--elasticity of bodies. figures. scientific amusements.--dance of electrified puppets.--silhouette portraits. figures. a sunshine recorder. figures. vi. medicine, hygiene, etc.--how cholera is spread. sulphurous acid and sulphide of carbon as disinfecting agents.--methods of burning the same. vii. miscellaneous.--improvised toys.--with numerous illustrations. the Æolian harp.--kircher's harp, made in .--frost and kastner's harp.--manner of making the harps. figures. how to break a cord with the hands. figure. an aquatic velocipede for duck hunting. engravings. skeleton of a bear found in a cave in styria, austria. viii. biography.--theodor billroth, prof, of surgery at vienna.--with portrait. * * * * * acknowledgment. the illustrations and descriptions we give this week, entitled "how to break a cord," "prestidigitation," "circle divider," "sulphurous acid," "production of gas," "aquatic velocipede," "several toys," "scientific amusements," are from our excellent contemporary _la nature_. * * * * * theodor billroth, professor of surgery at vienna. the well known surgeon, theodor billroth, was born on the island of rügen in . he showed great talent and liking for music, and it was the wish of his father, who was a minister, that he should cultivate this taste and become an artist; but the great masters of medicine, johannes mueller, meckel v. hemsbach, r. wagner, traube, and schönlein, who were billroth's instructors at greifswald, göttingen, and berlin, discovered his great talent for surgery and medicine, and induced him to adopt this profession. it was particularly the late prof. baum who influenced billroth to make surgery a special study, and he was billroth's first special instructor. in billroth received his degree as doctor at the university of berlin. after traveling for one year, and spending part of his time in vienna and paris, he was appointed assistant in the clinique of b. von langenbeck, berlin. at this time he published his works on pathological histology ("microscopic studies on the structure of diseased human tissues") which made him so well known that he was appointed a professor of pathology at greifswald in . mr. billroth did not accept that call, and was appointed professor of surgery at zurich in , and during that time his wonderful operations gave him a world-wide reputation. in the medical faculty of the vienna university concluded to appoint billroth as successor to prof. schuh, which position he still fills. [illustration: theodor billroth.] billroth is a master of surgical technique, and his courage and composure increase with the difficulty of the operation. he always makes use of the most simple apparatus and instruments, and follows a theoretically scientific course which he has never left since he adopted surgery as a profession, and by which he has directed surgery into entirely new channels. he has given special attention to the study of the healing of wounds, the development of swellings and tumors, and the treatment of wounds in relation to decomposition and the formation of proud flosh. he has had wonderful success in performing plastic operations on the face, such as the formation of new noses, lips, etc., from flesh taken from other parts of the body or from the face. although billroth devoted much of his time to the solution of theoretical problems, he has also been very successful as an operator. he has removed diseased larynxes, performed dangerous goiter operations, and successfully removed parts of the oesophagus, stomach, and intestines. billroth has been very careful in the selection of his scholars, and many of them are now professors of surgery and medicine in germany, belgium, and austria. they all honor and admire him, his courage, his character, his humane treatment of the sick and suffering, arid his amiability. the accompanying portrait is from the _illustrirte zeitung._ * * * * * how cholera is spread. dr. john c. peters, of this city, in a recent contribution to the _medical record_, gives the following interesting particulars: i have read many brilliant essays of late on these topics, but not with unalloyed pleasure, for i believe that many writers have fallen into errors which it is important to correct. no really well informed person has believed for a long time that carbolic alcohol will destroy the cholera poison; but many fully and correctly believe that real germicides will. it has been known since that microbes, bacilli, and bacteria could live in very strong solutions of carbolic alcohol, and that the dilute mineral acids, tannin, chloride, corrosive sublimate, and others would kill them. in cholera did not arise alone in egypt from filth, but from importation. it did not commence at alexandria, but at damietta, which is the nearest nile port to port said, which is the outlet of the suez canal. there were , deaths from cholera in the bombay presidency in . bombay merchants came both to port said and damietta to attend a great fair there, to which at least , people congregated, in addition to the , inhabitants. the barbers who shave and prepare the dead are the first registrars of vital statistics in many egyptian towns, and the principal barber of damietta was among the first to die of cholera; hence all the earliest records of deaths were lost, and the more fatal and infective diarrhoeal cases were never recorded. next the principal european physician of damietta had his attention called to the rumors of numerous deaths, and investigated the matter, to find that cases of cholera had occurred in may, whereas none had been reported publicly until june . a _zadig_, or canal, runs through damietta from one branch of the nile to another, and this is the principal source of the water supply. mosques and many houses are on the banks of this canal, and their drainage goes into it. every mosque has a public privy, and also a tank for the ablution, which all good mohammedans must use before entering a holy place. there was, of course, great choleraic water contamination, and a sudden outburst of cholera took place. the , people who came to the fair were stampeded out of damietta, together with about , of the inhabitants, who carried the disease with them back into egypt. then only was a rigid quarantine established, and a cordon put round damietta to keep everybody in, and let no one go out, neither food, medicines, doctors, nor supplies of any kind. such is nearly the history of every town attacked in egypt in . when the pestilence had been let out _en masse_, severe measures were taken to keep it in cairo, for up the nile was attacked long before alexandria suffered. this cholera broke out, as it almost always does in egypt, when the river nile is low and the water unusually bad. it disappeared like magic, as it always does in egypt, when the nile rises and washes all impurities away. there had been little or no cholera in egypt since , and there had often been as much filth as in . it has never become endemic there, as it is a rainless country and generally too dry for the cholera germ to thrive. marseilles had a small outbreak of cholera in the fall of , probably derived from egypt, which she carefully concealed. in addition, cholera was also brought to toulon from tonquin by the sarthe and other vessels. toulon concealed her cholera for at least seventeen days, and did not confess it until it had got such headway that it could no longer be concealed. at least twenty thousand italians fled from toulon and marseilles, and others were brought away in transports by the italian government. rome refused to receive any fugitives; genoa and naples welcomed them. there were at least three large importations into naples. the outbreak in genoa was connected with washing soiled cholera clothes in one of the principal water supplies of the city, and naples has many privy pits and surface wells. these privies, or _pozzis_, in the poorer parts of many italian towns, are in the yards or cellars, and are so arranged that when they overflow, the surplusage is carried through drains or gutters into the streets. in the lowest parts of toulon there were no privies at all, and the people emptied their chamberpots into the streets every morning. this flowed down toward the harbor, which is almost tideless. toulon always has much typhoid fever from this cause; but no cholera unless it is imported. the great outbreaks of cholera in paris in , , , and have been explained at last by dr. marcy. the canal de l'ourcq is one of the principal water sources of paris. the market boats or vessels upon it and at la villette are so numerous that marseilles and havre alone outrank it in shipping. the parts of paris which are always most severely attacked with cholera, and where the most typhoid fever prevails, are supplied with this water, into which not only all the filth of the boats goes, but many sewers empty. i agree with all that is generally said about civic filth favoring the spread of cholera, but it does not generate, but only supplies the pabulum for the germs. i believe as long as the croton water is kept pure there can be no general outbreak of cholera in new york, only isolated cases, or at most a few in each house, and those only into which diarrhoeal cases come, or soiled clothes are brought; that it will not spread even to the next house, and that there are no pandemic waves of cholera. i think it impossible to pump new york dock water into the sewers, and that it would be very injurious if it could be done. almost all our sewers empty into the docks, and the water there is of the foulest kind. i do not believe in a long quarantine, and think that of the dutch is the best. they only detained the sick, but took the addresses of all who were let through, or kept back all their soiled clothing, which they had washed, disinfected, and sent after their owners in three days. st. louis still has , privy pits and as many surface wells. the importation of cholera into st. louis is well proved for , , , , , and . those who used surface well water suffered much more than those who drank mississippi water, however foul that may have been. the history of cholera in st. louis has been better and more accurately written up quite lately by mr. robert moore, civil engineer, than that of any city in this country. he has kindly given me maps of the city, with every case marked down, with street and number, for all the epidemic. hypodermic injections of atropine and morphine have failed sadly in many cases. subcutaneous injections of large quantities of salt and water, with some soda, and large rectal injections of tannin and laudanum have been very successful in italy. if there is plenty of acid gastric juice in the stomach, the cholera poison and microbes may be swallowed with impunity. the worst cases of cholera are produced by drinking large quantities of cholera contaminated water, when the stomach is empty and alkaline. i think it probable that large quantities, as much as the thirst requires, of a weak acid water will prove very beneficial in cholera. water slightly acidulated with sulphuric, nitric, or muriatic acid will probably be the best, but it is hoped that phosphoric, acetic, and lactic acids will prove equally good. lemon juice and vinegar are merely acetates and citrates of potash, and are not as good. * * * * * it seems that the offensive smells noticed in the english houses of parliament last session have been traced to their source. it is found that the main sewer of the house of commons is very large and out of all proportion to the requirements, is of two different levels, and discharges into the street sewer within eighteen inches of the bottom of the latter drain. there is thus a constant backflow of sewage. another revelation is that the drain connected with the open furnace in the clock tower, for the purpose of ventilation, is hermetically closed at its opposite end. * * * * * sulphurous acid and sulphide of carbon. much attention has been paid in recent times to disinfecting agents, and among these sulphurous acid and sulphide of carbon must be placed in the list of the most efficient. mr. alf. riche has recently summed up in the _journal de pharmacie et de chimie_ the state of the question as regards these two agents, and we in turn shall furnish a few data on the subject in taking the above named scientist as a guide. mr. dujardin beaumetz some time ago asked messrs. pasteur and roux's aid in making some new experiments on the question, and has made known the result of these to the academy of medicine. at the cochin hospital he selected two rooms of , cubic feet capacity located in wooden sheds. the walls of these rooms, which were formed of boards, allowed the air to enter through numerous chinks, although care had been taken to close the largest of these with paper. in each of the rooms were placed a bed, different pieces of furniture, and fabrics of various colors. bromine, chlorine and sulphate of nitrosyle were successively rejected. three sources of sulphurous acid were then experimented with, viz., the burning of sulphur, liquefied sulphurous acid, and the burning of sulphide of carbon. the rooms were closed for twenty-four hours, and tubes containing different proto-organisms, and particularly the comma bacillus made known by koch, were placed therein, along with other tubes containing vaccine lymph. after each experiment these tubes were carried to mr. pasteur's laboratory and compared with others. [illustration: fig. .--burner for sulphur.] the process by combustion of sulphur is the simplest and cheapest. to effect such combustion, it suffices to place a piece of iron plate upon the floor of the room, and on this to place bricks connected with sand, or, what is better, to use a small refractory clay furnace (as advised by mr. pasteur), of oblong form, inches in width by in length, and having small apertures in the sides in order to quicken combustion. in order to obtain a complete combustion of the flowers of sulphur, it is necessary to see to it that the burning is effected equally over its entire surface, this being easily brought about by moistening the sulphur with alcohol and then setting fire to the latter. through the use of this process a complete and absolute combustion has been obtained of much as from to grains of sulphur per cubic foot. in the proportion of grains to the cubic foot, all the different culture broths under experiment were sterilized save the one containing the bacteria of charbon. as for the vaccine virus, its properties were destroyed. this economical process presents but two inconveniences, viz., the possibility of fire when the furnace is badly constructed, and the alteration of such metallic objects as may be in the room. in fact, the combustion of sulphur is attended with the projection of a few particles of the substance, which form a layer of metallic sulphide upon copper or iron objects. [illustration: fig. .--ckiandi bey's apparatus for burning carbon sulphide.] the use of liquid sulphurous acid in siphons does not offer the same inconveniences. these siphons contain about one and a half pounds of sulphurous acid. the proportion necessary to effect the sterilization of the culture broths is one siphon per cubic feet. in such a case the _modus operandi_ is as follows: in the middle of the room is placed a vessel, which is connected with the exterior by means a rubber tube that passes through a hole in the door. after the door has been closed, it is only necessary to place the nozzle of the siphon in the rubber tube, and to press upon the lever of the siphon valve, to cause the liquid to pass from the siphon to the interior of the vessel. the evaporation of the liquid sulphurous acid proceeds very rapidly in the free air. this process is an exceedingly convenient one; it does away with danger from fire, and it leaves the gildings and metallic objects that chance to be in the room absolutely intact. finally, the acid's power of penetration appears to be still greater than that which is obtained by the combustion of sulphur. it has but one drawback, and that is its high price. each siphon is sold to the public at the price of one dollar. to municipalities using sulphurous acid in this form the price would be reduced to just one-half that figure. it will be seen, then, that for a room of , cubic feet capacity the cost would be $ . or $ . . the combustion of sulphide of carbon furnishes an abundance of sulphurous acid, but has hitherto been attended with danger. this, however, has recently been overcome by the invention of a new burner by mr. ckiandi bey. the general arrangement of this new apparatus is shown in figs. and . mr. ckiandi's burner consists of an external vessel, a b c d. of tinned copper, containing a vessel, i h e f, to the sides of which are fixed three siphons, r, s. [illustration: fig. .--section of the apparatus.] to operate the burner, we place the cylindrical tube, k l m n, in the inner vessel, and pour sulphide of carbon into it up to the level _aa_. this done, we fill the external vessel with water up to the level _bb_. thanks to the siphons, the water enters the inner vessel, presses the sulphide of carbon, which is the heavier, and causes it to rise in the tube up to the level _a'a',_ where it saturates a cotton wick, which is then lighted. the upper end of the tube is surmounted with a chimney, pq. which quickens the draught. the combustion may be retarded or quickened at will by causing the level _bb_ of the water to rise or lower. the burner is placed in the room to be disinfected, which, after the wick has been lighted, is closed hermetically. when all the sulphide is burned it is replaced by water, and the lamp goes out of itself. the combustion proceeds with great regularity and without any danger. it takes about five and a half pounds for a room of , cubic feet capacity. the process is sure and quite economical, since sulphide of carbon is sold at about five cents per pound, which amounts to cents for a room of , cubic feet capacity. the burner costs ten dollars, but may be used for an almost indefinite period. the process of producing sulphurous acid by the combustion of sulphide of carbon is, as may be seen, very practical and advantageous. it does not affect metallic objects, and it furnishes a disinfecting gas continuously, slowly, and regularly. mr. ckiandi's burner may also be applied in several industries. it is capable of rendering great services in the bleaching of silk and woolen goods, and it may also be used for bleaching sponges, straw hats, and a number of other objects.--_la nature_. * * * * * the determination of graphite in minerals. by j.b. mackintosh. in many instances the accurate determination of the amount of graphite present in a rock has proved a rather troublesome problem. the first thought which naturally suggests itself is to burn the graphite and weigh the carbonic acid produced; but in the case of the sample which led me to seek for another method, this way could not be employed, for the specimen had been taken from the surface, and was covered and penetrated by vegetable growths which could not be entirely removed mechanically. add to this the fact of the presence of iron pyrites and the probable occurrence of carbonates in the rock, and it will be at once seen that no reliance could be placed on the results obtained by this suggested method. as the problem thus resolved itself into finding a way by which all interfering substances could be destroyed without affecting the graphite, it at once occurred to me to try the effect of caustic potash. i melted a few pieces of potash in a silver crucible until it had stopped spitting and was in quiet fusion. i then transferred the weighed sample to the crucible, the melted potash in which readily wetted the graphite rock. the mass was then gently heated, and occasionally stirred with a piece of silver wire. the heat never need be much above the melting point of the potash, though toward the last i have been in the habit of raising the temperature slightly, to insure the complete decomposition of the melt. when the decomposition is complete, which can be known by the complete absence of gritty particles, the crucible is cooled and then soaked out in cold water. this is very quickly accomplished, and we then see that we have an insoluble residue of graphite and a flocculent precipitate of lime, magnesia, iron hydrate, etc., while the organic matters have disappeared. the sulphides of iron, etc., have given up their sulphur to the potash, and everything except the graphite has suffered some change. the solution is now filtered through a weighed gooch crucible, the residue washed a few times with water, and then treated with dilute hydrochloric acid (followed by ammonia to remove any silver taken up from the crucible), which will dissolve all the constituents of the residue except the graphite, and after washing will leave the latter free and in a condition of great purity. as evidence of the accuracy of the method, i subjoin the results i obtained on a sample whose gangue was free from all organic and other impurities, consisting chiefly of quartz: new method. combustion in oxygen, weighing co_{ }. . . it is plain that such a result leaves nothing to be desired for the accuracy of the method, while, as regards time and trouble, the advantage lies on the side of the new method. i have completed a determination in less than two hours from the start, and did not hurry myself over it in any degree. fine pulverization of the sample is not essential, and in fact is rather detrimental, as the graphite, when fine, is more difficult to wash without loss. when operating on a coarse sample more time is necessarily taken, but the resulting graphite shows the manner of occurrence better, whether in scales or in the amorphous form. in consulting the literature bearing on the subject, i cannot find any mention of this method employed as an analytical process; it has, however, been previously described as a commercial method for the purification of graphite,[ ] and i understand has been tried on a small scale in this country. the method, though inexpensive, yet seems to have been abandoned for some reason, and i am not aware that it is now employed anywhere.--_sch. mines quarterly._ [footnote : schloffel, zeitschrift der k.k. geolog. reichanstalt, , p. .] * * * * * sulphocyanide of potassium. the elements of cyanogen, combined with sulphur, form a salt radical, sulphocyanogen, c_{ }ns_{ }, which is expressed by the symbol csy. the sulphocyanide of potassium, kcsy, is prepared by fusing ferrocyanide of potassium, deprived of its water of crystallization, intimately mixed with half its weight of sulphur and parts of carbonate of potassa. the molten mass, after having cooled, is exhausted with water, the solution evaporated to dryness, and extracted with alcohol, from which the crystals of the salt are separated by evaporation. it is also made by melting the ferrocyanide of potassium with sulphide of potassium. it is a white, crystallizable salt of a taste resembling that of niter, soluble in water and alcohol, and extremely poisonous. it dissolves the chlorides, iodides, and bromides of silver, is, therefore, a fixing agent, but has not come in general use as such. vogel speaks highly of it as an addition to the positive toning bath, although he prefers the analogous ammonium salt in the following formula: chloride of gold solution.... ( : ) c. cm. ( - / grains). sulphocyanide of ammonium ... grammes ( grains). water........ c. cm. ( ounces drachms grains). _ferrocyanide of potassium_--k_{ }cfy+ ho, or k_{ }c_{ }n_{ }fe+ ho, is generally known by the name of yellow prussiate of potassa. it contains ferrocyanogen, a compound radical, consisting of eq. of metallic iron and eq. of the elements of cyanogen, and is designated by the symbol cfy. the potassium salt is manufactured on a large scale from refuse animal matter, as old leather, chips of horn, woolen rags, hoofs, blood (hence its german name, "blutlaugen salz"), greaves, and other substances rich in nitrogen, by fusing them with crude carbonate of potassa and iron scraps or filings to a red heat, the operation to go on in an iron pot or shell, with the exclusion of all air. cyanide of potassium is generated in large quantities. the melted mass is afterward treated with hot water, which dissolves the cyanide and other salts, the cyanide being then quickly converted by the action of oxide of iron, formed during the operation of fusing, into ferrocyanide. the filtered solution is evaporated, crystallized, and recrystallized. the best temperature for making the solution is between and deg. f. the conversion of the cyanide into the ferrocyanide is greatly facilitated by the presence of finely divided sulphuret of iron and caustic potash. some years ago this salt was manufactured by a process which dispensed with the use of animal matter, the necessary nitrogen being obtained by a current of atmospheric air. fragments of charcoal, impregnated with carbonate of potassa, were exposed to a white heat in a clay cylinder, through which a current of air was drawn by a suction pump. the process succeeded in a chemical sense, but failed on the score of economy. richard brunquell passes ammonia through tubes filled with charcoal, and heated to redness so as to form cyanide of ammonium, which is converted into the ferrocyanide of potassium by contact with potash solution and suitable iron compounds. ferrocyanide of potassium is in large beautiful transparent four-sided tabular crystals, of a lemon-yellow color, soluble in four parts of cold and two of boiling water, insoluble in alcohol. exposed to heat it loses three eq. of water, and becomes anhydrous; at a high temperature it yields cyanide of potassium, carbide of iron, and various gases. this salt is said to have no poisonous properties, although the dangerous hydrocyanic acid is made from it. in large doses it occasions, however, vertigo, numbness, and coldness. it is used in various photographic processes. newton employs it in combination with pyrogallol and soda in the development of bromo-gelatine plates. the ferri or ferrid cyanide of potassium discovered by gmelin is often, but improperly, termed red prussiate of potash. it is formed by passing a current of chlorine gas through a solution of ferrocyanide of potassium until the liquid ceases to give a precipitate with a salt of sesquioxide of iron, and acquires a deep, reddish-green color. the solution is then evaporated, crystallized, and recrystallized. it forms regular prismatic or tabular crystals, of a beautiful ruby-red tint, permanent in the air, soluble in four parts of cold water. the crystals burn when introduced into the flame of a candle, and emit sparks. the theory of the formation of this salt is, that one eq. of chlorine withdraws from two eq. of the ferrocyanide of potassium, one eq. of potassium, forming chloride of potassium, which remains in the mother liquid. the reaction is explained by the following equation: (k_{ }cfy)+cl=k_{ }cfy_{ }+kcl. the radical ferridcyanogen, isomeric[ ] with ferrocyanogen, is supposed to be formed by the coalescence of two equivalents of ferrocyanogen, and is represented by the symbol cfdy; accordingly the formula of ferridcyanide of potassium is k_{ }cfdy. [footnote : isomeric bodies, or substances different in properties yet identical in composition, are of constant occurrence in organic chemistry, and stand among its most peculiar features.] ferridcyanide of potassium has found extensive application in photographic processes for intensifying negatives; those of eder, in combination with nitrate of lead, or selle's, with nitrate of uranium; ander's blue intensification of gelatine negatives, farmer's process of reducing intensity, the coloring of diapositives, the very important blue printing, and various others, are daily practiced in our laboratories. the ferrocyanide of potassium is a chemical reagent of great value, giving rise to precipitates with the neutral or slightly acid solutions of metals, like the beautiful brown ferrocyanide of copper, and that of lead. when a ferrocyanide is added to a solution of a sesquioxide of iron, prussian blue or ferrocyanide of iron is produced. the exact composition of this remarkable substance is not distinctly stated, as various blue compounds may be precipitated under different circumstances. berzelius gives the following account: eq. of ferrocyanide and eq. of sesquioxide of iron are mutually decomposed, forming eq. of prussian blue and eq. of the potassa salt, which remains in solution, or k_{ }cfy + (fe_{ }o_{ } no_{ }) = fe_{ }cfy_{ } + (ko,no_{ }). it forms a bulky precipitate of an intense blue, is quite insoluble in water or weak acids, with the exception of oxalic acid, with which it gives a deep blue liquid, occasionally used as blue ink. ferridcyanide of potassium, added to a salt of the sesquioxide of iron, yields no precipitate, but merely darkens the reddish-brown solution; with protoxide of iron it gives a blue precipitate, containing fe_{ }cfdy, which is of a brighter tint than that of prussian blue, and is known by the name of turnbull's blue. hence, the ferridcyanide of potassium is as excellent a test for protoxide of iron as the yellow ferrocyanide is for the sesquioxide.--_e., photo. times_. * * * * * foucault's apparatus for manufacturing illuminating gas and hydrogen. the illuminating gas and hydrogen apparatus, illustrated herewith, is adapted to all cases in which it is desirable to manufacture gas upon a small scale. through the use solely of oil or water, it produces illuminating gas or pure hydrogen for all the applications that may be required of them. it consists of three parts, viz., of a vaporizer, a, which converts the liquids into gas; of a distributer, b, which contains and distributes the liquids to be converted into gas, and of a regulator, c, which automatically regulates the flow of the liquids in proportion as they are used. [illustration: fig. .--foucault's gas apparatus.] in the vaporizer mr. foucault, the inventor of the apparatus, obtains a perfectly regular combustion through the use of a central column, , charged with fuel, closed at the upper part, open beneath, and entering a furnace that is fed by it with regularity, the zone of combustion not being able to extend beyond the level of the draught. the grate, , is capable of revolving upon its axis in order to separate the cinders. it also oscillates, and is provided with jaws for crushing the fuel; and it may likewise be lowered so as to let the fire drop into the ash-pan when it is desired to stop operations. the vaporizer, properly so called, is not placed directly over the fire, and for this reason the production of a spheroidal state of the liquid is avoided. it consists of a vessel, , into which the liquid is led by a pipe, . the cast-iron evaporating vessel, , is provided with appendages, _bis_, which dip into the liquid and bring about its evaporation. a refractory clay sleeve, , protects the lower part of the cylinder, , from the fire, and diminishes the smoke passages at . the vapor produced makes its way vertically through a layer of charcoal placed between the evaporating vessel, , and the receiver, , and serving to decompose the aqueous vapor formed. all clay and red and white lead joints are done away with in this part of the apparatus, as are also packing bolts. thus, at the upper part the cover, , is provided with a rim that enters a cavity filled with lead, so, too, the lower part of the evaporating vessel, , rests in a channel containing lead. there is also at , a joint of the same character for the rim of the external cylindrical vessel, . both this latter and the receiver, , dip beneath into a tank of water, . the distributer, b, is so arranged as to cause the water, and oil, and the liquids to be vaporized to flow with the greatest regularity, and proportionally to the consumption of the gas in cases where the latter is not stored up in a gas meter. the flow is controlled by cocks that are actuated by variations in the height of the regulator receiver. all the condensation that occurs in the various parts of the apparatus collects in a receptacle, , so arranged as to perform the office of a separator and set apart the oil at , and the water at , through the natural effect of their difference in density. this latter is likewise utilized for causing the oil to flow into the vaporizer through and , instead of using a graduated cock that receives a variable pressure from the receiver. in this way every cause of obstruction is avoided. [illustration: fig. .--section.] we have stated that the regulator, c, serves to automatically regulate the flow of the liquids proportionally to the consumption of the gases produced. to effect this a communication is established between the regulator receiver, , and the aperture through which the liquids flow, and the flow is thus modified by the valves, and . the water contained in the reservoir of the regulator serves to wash the gas which enters through a number of orifices in the disk, , this latter being fixed beneath the level of the water. the gas may be purified by dissolving metallic salts in the water. by means of the arrangement above described, there may be manufactured at will a rich gas from liquid hydrocarburets, hydrogen from water, and gas obtained by an admixture of two others simultaneously produced and combined in the apparatus.--_chronique industrielle._ * * * * * sugar nitro-glycerine. a new explosive has been discovered by m. roca, a french engineer, who communicates an account of it to _le génie civil_. the discovery was due entirely to scientific induction from some experiments made upon different specimens of dynamite, with a view to the determination of the effect on the explosive force of the various inert or at least slowly combustible substances with which nitro-glycerine is mixed to produce the dynamite of commerce. of late, in place of the infusorial earth which formed the solid portion of nobel's dynamite, such substances as sawdust, powdered bark, and even gunpowder, have been used, probably for the sake of economy alone, without, except in the latter case, any reference to the influence which they might have upon the combustion of the nitro-glycerine; but m. roca, in testing a variety of samples, was struck by the difference among them in regard to energy of explosion, and discovered that if a portion of free carbon, sufficient to combine with the oxygen disengaged from the nitro-glycerine, was present at the moment of detonation, the effect was greater than where, as in the case of gunpowder, the solid portion alone furnished oxygen enough to burn all the free carbon, without calling upon the nitro-glycerine for any. in fact, it appeared from experiment that the dose of carbon might with advantage be so great as not only to be itself oxidized into carbonic oxide by the oxygen of the nitro-glycerine, but to reduce the carbonic acid developed by the explosion of the latter itself into carbonic oxide. the limit of the advantageous effect of free carbon ceased here, and if more were added to the mixture, the cavities formed by the explosion in the lead cubes used for test were found simply lined with soot; but up to the limit necessary for converting all the carbon in the dynamite into carbonic oxide, the addition of a reducing agent was shown to be an important gain. this was confirmed by theory, which shows that pure nitro-glycerine, which is composed of six parts of carbon and two of hydrogen, combined with three times as much nitric acid and water, decomposes on explosion into six parts of carbonic acid, five of watery vapor, one of oxygen, and three of nitrogen, while the addition of seven more parts of free carbon to the mixture causes the development, by explosion, of thirteen volumes of carbonic oxide, five parts of watery vapor, and three of nitrogen, or twenty-one volumes of gas in place of fifteen. as the power of an explosive depends principally on the amount of gas which results from its sudden combustion, it was evident that the addition of pure or nearly pure carbon, in a condition to be readily combined with the other elements, ought to increase materially the force of nitro-glycerine, and m. roca experimented accordingly with an admixture of sugar, as a highly carbonized body immediately available, and found that three parts of this, mixed with seven parts of nitro-glycerine, detonated with a force from thirty to thirty-five per cent. greater than that of pure nitro-glycerine. many other organic carbonaceous substances may be employed in place of sugar, with various advantages. in comparing these simple compounds with the celebrated explosive gum, prepared by dissolving gun-cotton in nitro-glycerine, it is found that the latter is far inferior, having an energy very little superior to that of pure nitro-glycerine. * * * * * the circle-divider. this little apparatus, invented by prof. mora, of senlis, permits of dividing circumferences or circles into equal or proportional parts. it consists (fig. ) of a rule, a, divided into equal or proportional parts, which pivots in the manner of a compass around a rod, t, that serves as a central rotary point. along this rule moves a slide, r, provided with an aperture, c, which is made to coincide with one of the divisions. this division corresponds to the number of equal or proportional parts into which the circle is to be divided. the slide is provided with a wheel, e, that carries a point which serves at every revolution to trace the points that indicate the divisions of the circumference. [illustration: fig. .--mode of using the circle divider. ] the apparatus operates as follows: suppose, for example, that it becomes necessary to divide a circumference into equal parts: we make the aperture, c, coincide with the th division of the rule, and fix the point of the rod, t, in the center of the circumference, and cause the rule to revolve around it. the wheel, e, will revolve upon its axis, g, and, at every revolution, its point will make a mark which corresponds to the th part of the circumference-- circumf. c / circumf. c = r / r it is always necessary that the extremity of the wheel, e, and the center-point, t, shall be at the same height in order to have the divisions very accurate. [illustration: fig. .--the circle divider. ] * * * * * soluble glass. although the manufacture of soluble glass does not strictly belong to the glass maker's art, yet it is an allied process to that of manufacturing glass. of late soluble glass has been used with good effect as a preservative coating for stones, a fire-proofing solution for wood and textile fabrics. very thin gauze dipped in a solution of silicate of potash diluted with water, and dried, burns without flame, blackens, and carbonizes as if it were heated in a retort without contact of air. as a fire-proofing material it would be excellent were it not that the alkaline reaction of this glass very often changes the coloring matters of paintings and textile fabrics. since soluble glass always remains somewhat deliquescent, even though the fabrics may have been thoroughly dried, the moisture of the atmosphere is attracted, and the goods remain damp. this is the reason why its use has been abandoned for preserving theater decorations and wearing apparel. another application of soluble glass has been made by surgeons for forming a protecting coat of silicate around broken limbs as a substitute for plaster, starch, or dextrine. the only use where soluble glass has met with success is in the preservation of porous stones, building materials, paintings in distemper, and painting on glass. before we describe these applications, we will give the processes used in making soluble glass. the following ingredients are heated in a reverberatory furnace until fusion becomes quieted: , pounds white sand, pounds potash of °. this will produce , pounds of transparent, homogeneous glass, with a slight tinge of amber. this glass is but little soluble in hot water. to dissolve it, the broken fragments are introduced into a iron digester charged with a sufficient quantity of water, at a high pressure, to make a solution marking ° to ° baume. distilled or rain water should be used, as the calcareous salts contained in ordinary water would produce insoluble salts of lime, which would render the solution turbid and opalescent; this solution contains silica and potash combined together in the proportion of to . silicate of soda is made with parts of sand, parts carbonate of soda ( . ), and is to be melted in the same manner as indicated previously. soluble glass may also be prepared by the following method: a mixture of sand with a solution of caustic potash or soda is introduced into an iron boiler, under or atmospheres of pressure, and heated for a few hours. the iron boiler contains an agitator, which is occasionally operated during the melting. the liquid is allowed to cool until it reaches °, and is drawn out after it has been allowed to clear by settling; it is then concentrated until it reaches a density of . , or it may be evaporated to dryness in an iron kettle. the metal is not affected by alkaline liquors. the glass is soluble in boiling water; cold water dissolves but little of it. the solution is decomposed by all acids, even by carbonic acid. soluble glass is apparently coagulated by the addition of an alkaline salt; mixed with powdered matters upon which alkalies have no effect, it becomes sticky and agglutinative, a sort of mineral glue. to apply soluble glass for the preservation of buildings and monuments of porous materials, take a solution of silicate of potash of ° baume, dilute it with twice its weight of water, paint with a brush, or inject with a pump; give several coats. experience has shown that three coats applied on three successive days are sufficient to preserve the materials indefinitely, at a cost of about cents per square yard. when applied upon old materials, it is necessary to wash them thoroughly with water. the degree of concentration of the solutions to be used varies with the materials. for hard stones, such as sand and free stones, rock, etc., the solution should mark ° to ° baume; for soft stones with coarse grit, ° to °; for calcareous stones of soft texture, ° to °. the last coating should always be applied with a more dilute solution of ° to ° only. authorities are divided upon the successful results of the preservation of stone by silicates. some claim in the affirmative that the protection is permanent, while others assert that with time and the humidity of the atmosphere the beneficial effects gradually disappear. it might be worth while to experiment upon some of the porous sandstones, which, under the extreme influence of our climate, rapidly deteriorate; such, for instance, as the connecticut sandstone, so popular at one time as a building material, but which is now generally discarded, owing to its tendency to crumble to pieces when exposed to the weather even for a few years. soluble glass has also been used in germany to a great extent for mural painting, known as stereochromy. the process consists in first laying a ground with a lime water; when this is thoroughly dry, it is soaked with a solution of silicate of soda. when this has completely solidified, the upper coating is applied to the thickness of about one-sixteenth of an inch, and should be put on very evenly. it is then rubbed with fine sandstone to roughen the surface. when thoroughly dry, the colors are applied with water; the wall is also frequently sprinkled with water. the colors are now set by using a mixture of silicate of potash completely saturated with silica, with a basic silicate of soda (a flint liquor with soda base, obtained by melting parts sand with parts of carbonate of soda). as the colors applied do not stand the action of the brush, the soluble glass is projected against the wall by means of a spray. after a few days the walls should be washed with alcohol to remove the dust and alkali liberated. the colors used for this style of painting are zinc white, green oxide of chrome, cobalt green, chromate of lead, colcothar, ochers, and ultramarine. soluble glass has also been used in the manufacture of soaps made with palm and cocoanut oil; this body renders them more alkaline and harder. interesting experiments have been made with soluble glass for coloring corals and shells. by plunging silicated shells into hot solutions of salts of chrome, nickel, cobalt, or copper, beautiful dyes in yellow, green, and blue are produced. here seems to be a field for further application of this discovery. soluble glass has also been applied to painting on glass in imitation of glass staining. by using sulphate of baryta, ultramarine, oxide of chrome, etc., mixed with silicate of potash, fast colors are obtained similar to the semi-transparent colors of painted windows. by this means a variety of cheap painted glass may be made. should these colors be fired in a furnace, enameled surfaces would be produced. as a substitute for albumen for fixing colors in calico printing, soluble glass has been used with a certain degree of success; also as a sizing for thread previous to weaving textile fabrics. thus it would seem that this substance has been used for many purposes, but since its application does not seem to have been extended to any great degree, the defects here pointed out in its use as a fire-proofing material perhaps also exist, to a certain degree, in its other applications. in painting upon glass, for instance, it is asserted that the brilliancy and finish of ordinary vitrified colors cannot be obtained.--_glassware reporter._ * * * * * the jet ventilator. [illustration: korting's jet ventilator.] messrs. korting bros., of london, induced by the interest that has been directed to the separate ventilation of mines in which fire-damp is apt to form, have adopted for this purpose their jet ventilator. the instrument, which we illustrate in fig. , has been, we understand, considerable simplified, and adapted for the special object in view. the ventilators are worked by compressed air, and are so arranged that, without stopping their action, the quantity of air they deliver can be rapidly increased or diminished. this ample power of control has been arranged for by the special wish of the mining authorities, who wish to regulate the ventilation according to the development of fire-damp or the greater or less number of men at work. under circumstances of this kind the quantity of air taken into the mine can be changed instantly. the illustrations, figs. , , and , show different modes of fixing the jet ventilator. in fig. , it is arranged to blow the air forward; in fig. , it is shown exhausting the air; and in fig. , it is represented as exhausting and blowing simultaneously, the efficiency in each case being always the same. any bends in the conduit affect the result to a very slight degree, and the ventilator may be used with advantage when the conduit is divided as in fig. , in order to get the fresh air to different points. the ventilators are easily fixed to the air conduits. if they are to be connected to zinc air pipes, the pipe is simply slipped over the point, l. in fig. , and if to wooden conduits the apparatus is simply put into them, and if no other support is required. furthermore, they are so light that it suffices for one man to fix them or change their position. messrs. korting bros. advance the following claims for this mode of ventilating mines: certainty of action, no moving parts whatever, and, consequently, no need of lubrication; no need of attention. --_mech. world_. * * * * * on remelting of cast iron. from trials conducted by ledebur, it appears that cast iron is rendered suitable for foundry purposes--i.e., to fill the moulds well and to yield sharp and definite forms free of flaws, to be cut with a chisel, and turned on a lathe--through a certain percentage of graphite, whose presence depends on that of carbon and silicium. cast iron free of silicium yields on cooling the entire amount of carbon in the amorphous state, while presence of the former metal gives rise to the formation of graphite, and, consequently, causes a partial separation of carbon. iron suffers on casting loss of graphite, assumes a finely-grained texture, becomes hard and brittle, and is changed from gray to white. in view of the fact that samples of cast iron with equal percentage of silicium and carbon yield on casting a different product, it has become necessary to institute experiments as to the cause of this behavior. samples of cast iron were therefore repeatedly melted, and thin sections of each melt examined; these sections exhibited a gray color, though less apparent than in the unmelted sample, and possessed sufficient softness to admit boring and filing. during these processes of fusing, the amount of silicium, carbon, and manganese had been gradually decreased, and amounted to . , . , and . per centum for silicium in the three samples examined. it also was observed that the more manganese the iron contains the less readily the percentage of silicium is diminished; and since manganese is more subject to oxidation than silicium, it is capable to reduce silicic acid of the slag or lining to metal, and thus to augment the amount of silicium in cast iron. the percentage of carbon also suffers diminution by oxidation, which latter process is impeded by presence of manganese, a fact of some importance in melting of cast iron in the cupola furnace. an excess of manganese renders cast iron hard and brittle, and imparts to it the properties to absorb gases, while an amount of . per centum, as found in scotch iron, undoubtedly has the effect to produce those properties for which this iron is held in high repute. the amount of copper is not visibly altered by fusion, but that of phosphorus and sulphur slowly increased. experiments in regard to the relation between chemical composition and strength of the material have established that a large amount of silicium, graphite, manganese, and combined carbon reduce the elasticity, strength, and tenacity of cast iron, and that a limited percentage of silicium counteracts the injurious influence produced by an excess of combined carbon. on remelting of cast iron, increase in tensile strength was observed, which attained its maximum in iron with a small percentage of silicium after the third, and in such with a large amount after the fourth melting. the increase in tensile strength was accompanied by a loss of silicium, graphite, and manganese coupled with a simultaneous augmentation of combined carbon. a fifth melting of the cast iron renders it hard, brittle, and white, through oxidation of silicium and subsequent lowering of the amount of carbon. on lessening the percentage of combined carbon with formation of graphite the injurious influence of the accessorial constituents of cast iron is diminished, especially that produced by the presence of phosphorus.--_eisenhuettentechnik._ * * * * * feeding boilers at the bottom. one of the most important things to be considered in boiler construction is the position and arrangement of the feed apparatus, but it is, unfortunately, one of the elements that is most often overlooked, or, if considered at all, only in a very superficial manner. many seem to think that it is only necessary to have a hole somewhere in the boiler--no matter what part--through which water may be pumped, and we have all that is desired. this is a very grave error. many boilers have been ruined, and (we make the assertion with the confidence born of long experience) a large number of destructive explosions have been directly caused by introducing the feed water into boilers at the wrong point. on the location and construction of the feed depends to some extent the economical working of a boiler, and, to a great extent, especially with certain types of boilers, its safety, durability, and freedom from a variety of defects, such as leaky seams, fractured plates, and others of a similar kind. and it is unfortunately true that the type of boiler which from its nature is most severely affected by mal-construction, such as we are now speaking of, is the very one which is the oftenest subject to it. we are speaking now more particularly of the plain cylinder boiler, of which there are many in use throughout the country. plain cylinder boilers are, as a rule, provided with mud drums located near the back end. as a rule, also, these boilers are set in pairs over a single furnace, and the mud drum extends across beneath, and is connected to both, and one end projects through the setting wall at the side. our illustrations show a typical arrangement of this kind. fig. shows a transverse section of the boilers and setting, while fig. shows a longitudinal section of the same. it is a favorite method to connect the feed pipe, f, to the end of the mud drum which projects through the wall, and here the feed water is introduced, whether hot or cold; and there is really not so much difference after all between the two, for no matter _how_ effective a heater may be, the temperature to which it can raise water passing through is quite low compared with the temperature of the water in the boiler due to a steam pressure of say eighty pounds per square inch. the difference in the effect produced by feeding hot or cold water at the wrong place is one of degree, not of kind. when a boiler is under steam of say eighty pounds per square inch, the body of water in it will have a temperature of about degrees fahr., and the shell plates will necessarily be somewhat hotter, especially on the bottom (just _how_ much hotter will depend entirely upon the quantity of scale or sediment present). now introduce a large volume of cold water through an opening in the bottom, and what becomes of it? does it rise at once, and become mixed with the large body of water in the boiler? by no means. it _cannot_ rise until it has become heated, for there is a great difference between the specific gravity of water at °, or even ° fahr., and water at °. consequently, it "hugs" the bottom of the boiler, and flows toward the _front_ end, or hottest portion of the shell. now let us examine the effect which it produces. we know that wrought iron expands or contracts about part in , for each degree that its temperature is raised or lowered. this is equivalent to a stress of _one ton_ per square inch of section for every degrees. that is, suppose we fix a piece of iron, a strip of boilerplate, for instance, ¼ of an inch thick and inches wide, at a temperature of degrees fahr., between a pair of immovable clamps. then, if we reduce the temperature of the bar under experiment to that of melting ice, we put a stress of four tons upon it, or one ton for each inch of its width. [illustration: fig. ] now this is precisely what happens when cold water is fed into the bottom of a boiler. we have the plates of the shell at a temperature of not less, probably, than ° fahr. a large quantity of cold water, often at a temperature as low as ° fahr., is introduced through an opening in the bottom, and flows along over these heated plates. if it could produce its _full_ effect at once, the contraction caused thereby would bring a stress of ÷ = tons per square inch upon the bottom plates of the shell. but fortunately it cannot exert its full effect at once, but it _can_ act to such an extent that we have known it to rupture the plates of a new boiler through the seams on the bottom _no less than three times in less than six weeks_ after the boilers were started up. the effect in such cases will always be the most marked, especially if the plant is furnished with a heater, when the engine is not running, for then, as no steam is being drawn from the boilers, there is comparatively little circulation going on in the water in the boiler, and the water pumped in, colder than usual from the fact that the heater is not in operation, spreads out in a thin layer on the lowest point of the shell, and _stays there_, and keeps the temperature of the shell down, owing to the fires being banked or the draught shut, while the larger body of water above, at a temperature of from to degrees, keeps the upper portion of the shell at _its_ higher temperature. it will readily be seen that the strain brought upon the seams along the bottom is something enormous, and we can understand why it is that many boilers of this class rupture their girth seams while being filled up for the night after the engine has been shut down. to most persons who have but a slight knowledge of the matter, we fancy it would be a surprise to see the persistence with which cold water will "hug" the bottom of a boiler under such circumstances. we have seen boilers when the fire has been drawn, and cold water pumped in to cool them off, so cold on the bottom that they felt cold to the touch, and must consequently have had a temperature considerably below ° fahr., while the water on top, above the tubes, was sufficiently hot to scald; and they will remain in such a condition for hours. [illustration: fig. .] the only thing to be done, where feed connections are made in the manner described, is to change them, and by changing them at once much trouble, or even a disastrous explosion, may be avoided. put the feedpipe in through the front head, at the point marked _p_ in fig. , drill and tap a hole the proper size for the feed pipe, cut a long thread on the end of the pipe, and screw the pipe through the head, letting it project through on the inside far enough to put on a coupling, then screw into the coupling a piece of pipe not less than eight or ten feet long, letting it run horizontally toward the back end of the boiler, the whole arrangement being only from to inches below the water line of the boiler, and hot or cold water may be fed indifferently, without fear of danger from ruptured plates or leaky seams. in short, put in a "top feed," and avoid further trouble.--_the locomotive_. * * * * * [microscopical journal.] iron printing and microscopic photography. by c.m. vorce, f.r.m.s. i. formulas for printing solutions. _blue prints_.--the best formula for this process, of many that i have tried, is that furnished by prof. c.h. kain, of camden, n.j., in which the quantity of ammonio-citrate of iron is exactly double that of the red prussiate of potash, and the solutions strong. this gives strong prints of a bright dark blue, and prints very quickly in clear sunlight. dissolve six grains of red prussiate of potash in one drm. of distilled water; in another drm. of distilled water dissolve twelve grains of ammonio-citrate of iron. mix the two solutions in a cup or saucer, and at once brush over the surface of clean strong paper. cover the surface thoroughly, but apply no more than the paper will take up at once; it should become limp and moist, but not wet. the above quantity of solution, two drms., will suffice to sensitize ten square feet of paper, or three sheets of the "regular" size of plain paper, × . as fast as the sheets are washed over with the solution, hang them up to dry by one corner. the surplus fluid will collect in a drop at the lower corner, and can be blotted off. _black prints_.--wash the paper with a saturated solution of bichromate of potash, made quite acid with acetic acid. after printing, wash the prints in running water for twenty to thirty minutes, then float them face down on a weak solution (five to ten per cent.) of protosulphate of iron for five minutes, and wash as before. if preferred, the iron solution may be washed over the prints, or they may be immersed in it, but floating seems preferable. after the second washing, wash the prints over with a strong solution of pyrogallic acid, when the print will develop black, and the ground, if the washings were sufficient, will remain white. a final washing completes the process. if a solution of yellow prussiate of potash be used in place of the pyro solution, a blue print is obtained. bichromate prints can be made on albumenized paper by floating it on the solution, and by using a saturated solution of protosulphate of iron and a saturated solution of gallic acid. very fine prints can be so produced nearly equal to silver prints, and at somewhat less cost, but with a little or no saving of time or labor. _chief proof solution_.--if old oxalate developer be exposed in a shallow vessel in a warm place, a deposit of light green crystals will be formed, composed of an impure oxalate of iron. if these crystals be dissolved in water, and paper washed with a strong solution, when dry it may be exposed in the printing-frame, giving full time. the image is very faint, but on washing in or floating on a moderately strong solution of red prussiate of potash for a minute or less, a blue positive is produced, which is washed in water as usual to fix it. the unused developer produces the best crystals for the purpose, and the pure ammonio-oxalate is vastly better than either. all of the above operations, except the printing, should be carried on in the dark room, or by lamp or gas light only. the solutions and the paper should also be kept in the dark, and prepared as short a time as possible before use. ii. compound negatives. in photographing with the microscope, it frequently occurs that the operator, instead of devoting a negative to each of two or more similar objects for comparison, printing both upon the same print, prefers to have the whole series upon one negative, and taking from this a single print. there is often room for two or more images upon the same plate. if the center of the plate is devoted to one, obviously no more can be accommodated on it, but by placing one at each end, or one on each quarter of the plate, both economy of plates and convenience of printing are secured. the end may be readily accomplished by matting the plate as a negative is matted in printing. suppose it be desired to photograph four different species of acari on one plate, the image of each when magnified to the desired extent only covering about one-fourth the exposed area of the plate. first, a mat is prepared of card-board or thick non-actinic paper, which is adjusted to exactly fill the opening of the plate holder, lying in front of and close against the plate when exposed, and having one-quarter very exactly cut out. a convenient way to fit this mat is to leave projecting lugs on each side at exactly the same distance from the ends, and cut notches in the plate-holder into which the lugs may closely fit. if this work is carefully done, the mat may be reversed both sidewise and endwise, and the lugs will fit the notches; if so, it is ready for use. the object being focused upon the focusing glass or card, the camera is raised one-half the vertical dimension of the plate and displaced to one side half the horizontal dimension, when the image will be found to occupy one-quarter of the plate. the mat being placed in the plate holder, a focusing glass is inserted in the position the plate will occupy, and final adjustment and focusing made. the plate is then marked on one corner on the film side with a lead pencil, placed in the holder without disturbing the mat, and the exposure made. when the plate is replaced for a second exposure, either the mat is reversed or the plate turned end for end; but it is best to always place the plate in the holder in the same position and change the mat to expose successive quarters, but this requires the camera to be moved for each exposure. with similar objects, and some judgment in making two exposures, negatives may be made with almost exactly the same density in each quarter, and by cutting out slightly less than one-quarter of the mat the four images will be separated by black lines in the print; by cutting out a trifle more than the exact quarter, they will be separated by white lines instead of black. * * * * * practical directions for making lantern transparencies. [footnote: abstract of a paper communicated to the glasgow and west of scotland amateur photographic association.--from the _photographic news_.] by t.n. armstrong. when the season for out-door work closes, amateurs begin to look about for means of employment during the dark evenings. there is, fortunately, no necessity for being idle, or to relinquish photographic pursuits entirely, even though the weather and light combine to render out-door work almost impracticable; and most amateurs will be found to have some hobby or favorite amusement which enables them to keep in practice during those months when many channels of employment are closed to them; and probably one of the most popular as well as the most pleasing occupations is the production of transparencies for the lantern. it is not my desire to enter into any discussion as to this or that being the best means of producing these delightful pictures, but merely to describe a way by which a pleasant evening can be spent at photography, and slides produced of much excellence by artificial light. to-night i propose, by the aid of artificial light, to make a few slides with beechy's dry plates. on the whole, i have been most successful with them, and have obtained results more satisfactory than by any of the other processes i have tried. i do not say that results quite as good cannot be obtained by any other method, for i know manipulative skill plays a most important part in this class of work. when i first took up the making of transparencies with wet collodion, i was told that my sorrows would not be far to seek, and so i soon found out. need i tell you of all my failures, such as films floating off the glass, oyster-shell markings, pin-holes, films splitting when dry, etc., etc., not to speak of going to business with fingers in fearful state with nitrate of silver and iron developer? now all these miseries have gone, and i can, with dry collodion plates, work with the greatest of comfort, and obtain results quite equal to the best products of any method. it may be interesting to some to know the formula by which the emulsion is made, and as the making of it is by no means a difficult operation, i may be pardoned if, before going fully into the more practical part of my paper, i describe the formula, and also the manner in which i coat and dry the plates. the formula is as follows, for which the world is indebted to canon beechy: in ounces of absolute alcohol dissolve drachms of anhydrous bromide of cadmium. the solution will be milky. let it stand at least twenty-four hours, or until perfectly clear; it will deposit a white powder. decant carefully into an -ounce bottle, and add to it a drachm of strong hydrochloric acid. label this "bromide solution;" and it is well to add on the label the constituents, which will be found to be nearly: alcohol. ounce. bromide of cadmium. grains. hydrochloric acid. drops. this solution will keep for ever, and will be sufficient to last two or three years, and with this at hand you will be able in two days to prepare a batch of plates at any time. in doing so, you should proceed thus: make up your mind how many plates you mean to make, and take of the above accordingly. for two dozen ½-plates or four dozen ¼ by ¼, dissolve by heat over, but not too near, a spirit lamp, and by yellow light, grains of nitrate of silver in ounce of alcohol . . while this is dissolving in a little florence flask on a retort stand at a safe distance from the lamp--which it will do in about minutes--take of the bromized solution ½ an ounce, of absolute ether ounce, of gun-cotton grains; put these in a clean bottle, shake once or twice, and the gun-cotton, if good, will entirely dissolve. as soon as the silver is all dissolved, and while quite hot, pour out the above bromized collodion into a clean -ounce measure, having ready in it a clean slip of glass. pour into it the hot solution of silver in a continuous stream, stirring rapidly all the while with a glass rod. the result will be a perfectly smooth emulsion without lumps or deposit, containing, with sufficient exactitude for all practical purposes, grains of bromide, grains of nitrate of silver, and drops of hydrochloric acid per ounce. put this in your stock solution bottle, and keep it in a dark place for twenty-four hours. when first put in, it will be milky; when taken out, it will be creamy; and it will be well to shake it once or twice in the twenty-four hours. at the end of this time you can make your two dozen plates in about an hour. proceed as follows: have two porcelain dishes large enough to hold four or six of your plates; into one put sufficient clean water to nearly fill it, into the other put ounces of clear, flat, _not acid,_ bitter beer, in which you have dissolved grains of pyrogallic acid. pour this through a filter into the dish, and avoid bubbles. if allowed to stand an hour, any beer will be flat enough; if the beer be at all brisk, it will be difficult to avoid small bubbles on the plate. at all events, let your preservative stand while you filter your emulsion. this must be done through perfectly clean cotton-wool into a perfectly clean collodion bottle; give the emulsion a good shaking, and when all bubbles have subsided, pour it into the funnel, and it will go through in five minutes. the filtered emulsion will be found to be a soft, smooth, creamy fluid, flowing easily and equally over the plates. coat with it six plates in succession, and place each, as you coat it, into the water. by the time the sixth is in, the first will be ready to come out. take it out, see that all greasiness is gone, and place it in the preservative, going on till all the plates are so treated. a very handy way of drying is to have a flat tin box of the usual hot plate description, which fill with hot water, then screw on the cap; on this flat tin box place the plates to dry, which they will do rapidly; when dry, store away in your plate box, and you will have a supply of really excellent dry collodion plates. just a word as to the preparation of the glasses before coating. it is very generally considered that it is better the glasses receive either a substratum of albumen or very weak gelatine. i use the latter on account of the great ease of its preparation. after your glasses are well cleaned, place them in, and rub them with a weak solution of hydrochloric acid of the strength of ounces acid to ounces water. prepare a solution of gelatine grain to the ounce of water, rinse the plate after removal from the acid mixtures, and coat twice with the above gelatine substratum; the first coating is to remove the surplus water, and should be rejected. rear the plates up to drain, and dry in a plate rack or against a wall, and be careful to prevent any dust adhering to the surface while wet. having now described the plates i intend to use, let us next consider what a transparency is, that we may understand the nature of the work we are undertaking. you are all aware that if we take a negative, and in contact with it place a sheet of sensitized paper, we obtain a positive picture. substitute for the paper a sensitive glass plate, and we obtain also a positive picture, but, unlike the paper print, the collodion or other plate will require to be developed to bring the image into view. now this is what is termed making a transparency by contact. it often happens, however, that a lantern slide ¼ by ¼ has to embrace the whole of a picture contained in a much larger negative, so that recourse must be had to the camera, and the picture reduced with the aid of a short focus lens to within the lantern size; this is what is called making a transparency by reduction in the camera. both cases are the same, however, so far as the process being simply one of printing. those who have never made a transparency will have doubtless printed silver prints from their negatives, and when printing, how often do you find that to secure the best results you require to have recourse to some little dodge. now, let us bear this in mind when using such a negative for the printing of a transparency, for, as i have said before, it is only a process of printing, after all. although we cannot, when using a sensitive plate, employ the same means of dodging as in the case of a silver print, still we are not left without a means of obtaining the same results in a different way, and this just brings me to what i have already hinted at previously, that a deal more depends on the manipulative skill of the operator than in the adoption of any particular make plate or formula; and not only does this manipulative skill show itself in the exposure, development, etc., but likewise comes into play in a marked manner even in the preparation of the negative for transparency printing. let me deal with the latter point first. you will at once understand that a negative whose size bears a proportion similar to ¼ by ¼ will lend itself more easily to reduction; thus whole plate or half plate negatives are easy of manipulation in this respect, and require but little doing up. but as other sizes have at times to be copied into a disk¼ by ¼, recourse must be had to a sort of squaring of the negative. now, here i have a negative ¼ by ½, which is perhaps the worst of all sizes to compress into the lantern shape, so i have, as it were, to square this negative, and this i do by simply adding to sky. i take a piece of card-board and gum it on to the glass side of the negative, and this addition gives me a size that lends itself easily to reduction to the lantern disk, and in no way detracts from the picture. having said so much about making up the size, let me add a few words as to other preparations that are sometimes necessary. in a good lantern transparency, it is, of all things, indispensable that the high lights be represented by pure glass, absolutely clean in the sense of its being free from any fog or deposit, to even the slightest degree; it is also necessary that it be free from everything of heaviness of smudginess in the details. to obtain these results, i generally have recourse to the strengthening of the high lights of my negatives, and this i do with a camel's hair brush and india ink, working on the glass side. i nearly always block out my skies, and so strengthen the other parts of my negatives, that i can rely on a full exposure without fear of heaviness or smudginess. this blocking out is easily done. haying said so much about the preparation of the negative, let me now describe the apparatus i use. i have here an ordinary flat board, and here my usual camera; it is the one i use both for outside and inside work. it is a whole-plate one, very strongly made, and has a draw of twenty-three inches when fully extended; but this is not an unusual feature, as nearly all modern cameras have their draw made as long as this one. the lens i use is a ross rapid symmetrical on five inches focus, and here i have a broken-down printing frame with the springs taken off, and here a sheet of ground glass. this is all that is required. i mention this because i find it generally believed that a special camera is required for this work, such as to exclude all light between the negative and the lens; in my practice i have found this unnecessary. there is nothing to hinder the use of ordinary cameras, provided the draw is long enough, and the lens a short focus one. now let me describe how to go to work. i take the negative and place it in the printing-frame, holding it in its place with a couple of tacks, film-side next the lens, just as in printing; then stand the printing frame on its edge on the flat board, and place the ground glass in front of it--when i say in front of it, i mean not between the negative and lens, but between the light and the negative. the ground glass can conveniently be placed in another printing frame, and both placed up against each other. i then bring my camera into play, and so adjust the draw and distance from the negative, till i get the picture within the disk on my ground glass. i find the best way is to gum a transparency mask on the inside of the ground glass; this permits of the picture being more easily brought within the required register. this done, focus sharply, cap the lens, and then proceed to make the exposure. now, what shall i say regarding exposure? just let us bear in mind again that it is merely a printing process we are following up, as you will all know that in printing no two negatives are alike in the time they require. so in this case no two negatives are the same in their required exposure. still, with the plates i am going to use, so wide is their range for exposure that but few failures will be made on this score, provided we are on the safe side, and expose fully. although these plates are not nearly so fast as gelatine plates, it may surprise you to be told that working with a negative which to daylight at this dull time of the year required an exposure of sixteen minutes, will, i hope, give me good results in about a tenth of this time; and this i obtain by burning magnesium ribbon. at first the error i fell into when using magnesium ribbon was too much concentration of light. i now never allow the ribbon, when burning, to remain in one position, but keep it moving from side to side, and up and down, in front of the ground glass while making my exposure; and if there be any dense place in the negative which, as in printing, would have required printing specially up, i allow the light to act more strongly on that part; the result, as a rule, being an evenly and well exposed plate. i must not forget to explain to you the manner in which i coil up the ribbon before i set it alight. i take an ordinary lead pencil, and wind the ribbon round and round, thus making a sort of spiral spring; this done, i gently pull the coils asunder. i then grasp the end of the ribbon with a pair of pincers, light the other end, and make my exposure. having said so much regarding exposure, i shall now proceed to deal with development. you will see me use a canary light, with which i can easily see to read a newspaper. it may cause some of you surprise to see me use so much light. it is the same lamp that i use for developing all my rapid bromide plates; it is the best lamp i ever used. the canary medium is inserted between the two sheets of glass ¼ by ½, the two glasses are then fastened on to the tin with gummed paper, a few holes are bored in the back for air, a funnel let in, and the thing is complete. the formula for development is as follows: pyro. grains. methylated spirits. ounce. bromide of potash. grams. water. ounce. carbonate ammonia. grains. water. ounce. mix drops pyro with from to drops bromide, then add drachms ammonia solution and drachms of water. i find a thin negative requires a slow development, and so gain contrast; while hard negatives are best over-exposed and quickly developed. the plate is first placed in water or rinsed under a gentle stream from the tap till all greasiness has disappeared, it is then placed in a flat dish, and the developer applied. should it be found that some parts of the picture are denser printed than should be by the ribbon acting more strongly on some particular part--this is often the case if the negative has been thinner in some parts than others, through uneven coating of the plate--the picture need not be discarded as a failure, for i will explain to you later on how to overcome this difficulty. fix the plate in hypo--the fixing takes place very quickly--then examine the picture for the faults above described; if they are found, wash the plate under the tap gently, and bring into operation a camel's hair brush and a weak solution of cyanide of potassium. apply the brush to the over-printed parts, taking care not to work on the places that are not too dense. do not be afraid to use plenty of washing while this is being done; let it be, as it were, a touch of the brush and then a dash of water, and you will soon reduce the over-printed parts. it only requires a little care in applying the brush. after this wash well, and should it be deemed necessary to tone to a black tone, use a weak solution of bichloride of platinum and chloride of gold, or a very weak solution of iridium, in equal quantities, allowing the picture to lie in the solution till the color has changed right through to the back of the glass. should a warm pinkish tone be desired, i tone with weak solutions of ferri cyanide of potassium, nitrate of uranium, and chloride of gold in about equal quantities. after toning, wash well and dry; they dry quickly. varnish with soehnee crystal varnish, then mount with covering glasses, and mark. bind round the edges with paper and very stiff gum, and the picture is complete. the making of a really good transparency is by no means an easy or pleasant task with a wet collodion plate, but with these dry plates an amateur can, with a little practice, produce comfortably slides quite equal to those procurable from professional makers. * * * * * the honigmann fireless engine. the invention of a self propelling engine, capable of working without fuel economically and for a considerable time, has often been attempted, and was, perhaps, never before so nearly accomplished as about the time of the introduction into practical use of faure's electric storage batteries; but at the present moment it appears that electric power has to give way once more to steam power. mr. honigmann's invention of the fireless working of steam engines by means of a solution of hydrate of soda--nao ho--in water is not quite two years old, and has in that time progressed so steadily towards practical success that it is reasonable to expect its application before long in many cases of locomotion where the chimney is felt to be a nuisance. the invention is based upon the discovery that solutions of caustic soda or potash and other solutions in water, which have high boiling points, liberate heat while absorbing steam, which heat can be utilized for the production of fresh steam. this is eminently the case with solutions of caustic soda, which completely absorb steam until the boiling point is nearly reached, which corresponds to the degree of dilution. if, therefore, a steam boiler is surrounded by a vessel containing a solution of hydrate of soda, having a high boiling point, and if the steam, after having done the work of propelling the pistons of an engine, is conducted with a reduced pressure and a reduced temperature into the solution, the latter, absorbing the steam, is diluted with simultaneous development of heat, which produces fresh steam in the boiler. this process will be made clearer by referring to the following table of the boiling points of soda solutions of different degrees of concentration, and by the description of an experiment conducted by professor riedler with a double cylinder engine and tubular boiler as shown in fig. : +---------------------+------------------+---------------------- | | boiling point in | steam pressure above | solution of soda. | centigrades. | atmospheric pressure | | | in atmospheres. +---------------------+------------------+---------------------- | nao ho + h o | deg. c. | atm. | " + " | . " | " | " + " | " | " | " + " | . " | . " | " + " | . " | . " | " + " | " | . " | " + " | . " | . " | " + " | " | . " | " + " | " | . " | " + " | " | . " | " + " | " | . " | " + " | " | . " | " + " | " | . " | " + " | . " | . " | " + " | " | . " +---------------------+------------------+---------------------- _experiment no. _.[ ]--the boiler of the engine, fig. , was filled with kilogs. water of two atmospheres pressure and a temperature of about deg. cent.; the soda vessel with kilogs. of soda lye of . per cent. water and a temperature of deg. cent., its boiling point being about deg. cent. the engine overcame the frictional resistance produced by a brake. at starting the temperature of both liquids had become nearly equal, viz., about deg. cent. the temperature of the soda lye could therefore be raised by deg. cent, before boiling took place, but, as dilution, consequent upon absorption of steam would take place, a boiling point could only be reached less than deg. cent., but more than deg. cent. the engine was then set in motion at revolutions per minute. the steam passing through the engine reached the soda vessel with a temperature of deg. cent.; the temperature of the soda lye began to rise almost immediately, but at the same time the steam boiler losing steam above, and not being influenced as quickly by the increased heat below, showed a decrease of temperature. the difference of the two temperatures, which was at starting . deg. cent., consequently increased to . deg. cent, after min., the boiler having then its lowest temperature of . deg. cent. after that both temperatures rose together, the difference between them increasing slightly to . deg. cent., and then decreasing continually. after hours min., when the engine had made , revolutions, the soda solution had reached a temperature of . deg. cent., which proved to be its boiling point. the steam from the engine was now blown off into the open air during the next min. this lowered the temperature of both water and soda lye by deg. and re-established its absorbing capacity. the steam produced under these circumstances had of course a smaller pressure than before, in this way the engine could be driven at reduced steam pressures until the resistance became relatively too great. the process described above is illustrated by the diagram fig. , which is drawn according to the observations during the experiment. [footnote : zeitschrift d. vereins deutscher ingenieur, , p. ; , p. .] [illustration: fig. .] [illustration: fig. .] the constant rise of both temperatures during the first two hours, which is an undesirable feature of this experiment, was caused by the quantity of soda lye being too great in proportion to that of water, and other experiments have shown that it is also caused by an increased resistance of the engine, and consequent greater consumption of steam. in the latter part of the experiment, where the engine worked with expansion, the rise of the temperature was much less, and by its judicious application, together with a proper proportion between the quantities of the two liquids in the engines, which are now in practical use, the rising of the temperatures has been avoided. the smaller the difference is between the temperatures of the soda lye and the water the more favorable is the economical working of the process. it can be attained by an increase of the heating surface as well as by a sparing consumption of steam, together with an ample quantity of soda lye, especially if the steam is made dry by superheating. in the diagrams figs. and , taken from a passenger engine which does regular service on the railway between wurselen and stolberg, the difference of the two temperatures is generally less than. deg. cent. these diagrams contain the temperatures during the four journeys _a b c d_, which are performed with only one quantity of soda lye during about twelve hours, and show the effects of the changing resistances of the engine and of the duration of the process upon the steam pressure, which, considering the condition of the gradients, are generally not greater than in an ordinary locomotive engine. it can especially be seen from these diagrams that an increase of the resistance is immediately and automatically followed by an increased production of steam. this is an important advantage of the soda engine over the coal-burning engine, in consequence of which less skill is required for the regular production of steam power. the tramway engines of more recent construction according to honigmann's system--figs. and --are worked with a closed soda vessel in which a pressure of / to ½ atmospheres is gradually developed during the process. while the counter pressure thus produced offers only a slight disadvantage, being at an average only / atmosphere, the absorbing power of the soda lye is materially increased, as shown by the following table, and it is, therefore, possible to work with higher pressures than with an open soda vessel. besides this great advantage, it is also of importance that the pressure in the steam boiler can be kept at a more uniform height. [illustration: fig. .] [illustration: fig. .] table.-- _kilogs. soda lye containing parts water with a corresponding boiling point of deg. cent. absorb steam as follows_: +----------------------------------+--------------+---------------+ |final pressure in condenser. | | | +----------------------------------+pressure in |corresponding | | | ½ atm. | atm. | ½ atm.|steam boiler. | temperature. | +----------------------------------+--------------+---------------+ | kil.| kil.| kil.| kil.| atm. | . deg. c. | | " | " | " | " | " | . " | | " | " | " | " | " | . " | | " | " | " | " | " | . " | | " | " | " | " | " | . " | | " | " | " | " | " | . " | | ½ " | " | " | " | " | . " | | " | " | " | " | " | . " | | " | " | " | " | " | . " | | " | " | " | " | " | . " | | " | " | " | " | " | . " | | " | " | " | " | " | . " | +-------+--------+--------+--------+--------------+---------------+ not the least important part of the process with regard to its economy is the boiling down of the soda lye in order to bring it back to the degree of concentration which is required at the beginning of the process. this is done in fixed boilers at a station from which the engines start on their daily service, and to which they return for the purpose of being refilled with concentrated soda lye. it is clear that a closed soda vessel has produced as much steam when the process is over as it has absorbed, and the quantity of coal required for the evaporation of water in concentrating the soda lye can therefore be directly compared with that required in an ordinary engine for the production of an equal quantity of steam. the boiling down of the soda lye requires, according to its degree of concentration, more coal than the evaporation of water does under equal circumstances, and disregarding certain advantages which the new engine offers in the economy of the use of steam, a greater consumption of coal must be expected. but even at the small installation for the aix la chapelle-burtscheid tramway with only two boilers of four square meters heating surface each, made of cast iron mm. thick, kilog. of coal converts kilogs. of water contained in the soda lye into steam, while in an ordinary locomotive engine of most modern construction the effect produced is not greater than in . there can be no doubt that better results could be obtained if the installation were larger, the construction of the boilers more scientific, and their material copper instead of cast iron; but even without such improvements the cost of boiling down the soda lye might be greatly lessened by the use of cheaper fuel than that which is used in locomotive engines, and by the saving in stokers' wages, since stokers would not be required to accompany the engines. [illustration: fig. ] [illustration: fig. ] apart from these considerations, the honigmann engines have the great advantage that neither smoke nor steam is ejected from them, and that they work noiselessly. the cost of the caustic soda does not form an important item in the economy of the process, as no decrease of the original quantities had been ascertained after a service of four months duration. besides the passenger engine already referred to, which was tested by herr heusinger von waldegg[ ] in march, , and which since then does regular service on the stolberg-wurselen railway, there are on the aix la chapelle-julich railway two engines of , kilogs. weight in regular use, which are intended for the service on the st. gothard railway. their construction is illustrated in figs. and , and other data are given in a report by the chief engineer of the aix la chapelle-julich railway, herr pulzner, which runs as follows: wurselen, dec. , . [footnote : z.d.v.d.i., , p. ] [illustration: diagrams for the calculation of stresses in bowstring girders.] a trial trip was arranged on the line haaren-wurselen, the hardest section of the aix la chapelle-julich railway. this section has a gradient of in on a length of kilos; and two curves of and meters radius and meters length. the goods train consisted of twenty-two goods wagons, sixteen of which were empty and six loaded. the total weight of the wagons was , kilogs., and this train was drawn by the soda engine with ease and within the regulation time, while the steam pressure was almost constant, viz., five atmospheres. the greatest load admissible for the coal burning engines of , kilogs. weight on the same section is , kilogs. [illustration: fig. .] [illustration: fig. .] proof is therefore given that the soda engine has a working capacity which is at least equal to that of the coal burning engine. the heating surface of the soda engine, moreover, is square meters, while that of the corresponding new henschel engine is square meters. on a former occasion i have already stated that the soda engine is capable not only of performing powerful work and of producing a large quantity of steam during a short time, but also of travelling long distances with the same quantity of soda. thus, for example, a regular passenger train, with military transport of ten carriages, was conveyed on nov. , , from aix la chapelle to julich and back, i.e., a distance of kilos, by means of the fireless engine. the gradients on this line are in , in , and in , being a total elevation of about meters. for a performance like this a powerful engine is required, and a proof of it can be recognized in the consumption of steam during the journey, for the quantity of water evaporated and absorbed by ½ to cubic meters soda lye was , liters. another certificate concerning the tramway engine illustrated in figs. and is of equal interest, and runs as follows: aix la chapelle, jan. , . a fireless soda engine, together with evaporating apparatus, has been at work on the aix la chapelle-burtscheid tramway for the last half year. in order to test the working capacity of this locomotive engine, and the consumption of fuel on a certain day, the honigmann locomotive engine was put to work this day from : o'clock a.m. till o'clock p.m., with a pause of three-quarters of an hour for the second quantity of soda lye. the engine was, therefore, at work for fully ½ hours, _viz._, ½ hours, with the first quantity, and five with the second. the distance between heinrichsalle and wilhelmstrasse, where the engine performed the regular service, is kilo, and there are gradients of about in in meter length. " " " " " " " " this distance was traversed sixty-four times, the total distance, including the journeys to the station, being kilos. the engine gives off fully -horse power on the steepest gradient, the total traction weight being ½ to tons; it is worked with an average steam pressure of atmospheres, and has cylinders of mm. diameter and mm. stroke, cog wheel-gear of to , and driving wheels of mm. diameter. the quantity of water evaporated during the service time of ½ hours was found to be about , kilogs., consequently about kilogs. steam was absorbed by one quantity of soda, the weight of which was ascertained at about , kilogs. the averaging heating surface is . square meters; the difference of temperature between soda lye and water was toward the end only deg. cent.; kilogs. pitcoal were used for boiling down the lye for the ½ hours' service, which corresponds to a . fold evaporation. (signed) m.f. gutermuth, assistant for engineering at the technical high school. haselmann, manager of the aix la chapelle-burtscheid tramway. here are some unquestionable results. for nearly a year the first railway engine, and for six months the first tramway engine of this new construction, have been introduced into regular public service, and been open to public inspection as well as to the criticism of the scientific world. they are worked with greater ease and simplicity than ordinary locomotive engines; the economy of their working appears, allowing for shortcomings unavoidably attached to small establishments, to be at least equally great: they do not emit either steam or smoke, and their action is as noiseless as that of stationary engines. in view of these facts it might be expected that railway managers, who are continually told that the smoke of their engines is a serious annoyance to the public, would be eager to make themselves acquainted with them; it might, in particular, be expected that the managers of the underground and suburban railways of this metropolis would lose no time in making experiments on their own lines--if only by converting some of their old engines into those of the fireless system--and assist a little in the development of an invention, in the success of which they have a tangible interest which is much greater than that of any railway on the continent, but there is no sign yet of their having done anything.--_e., in the engineer_. * * * * * simple methods of calculating stresses in girders. by charles lean, m. inst. c.e. _bowstring girders._--having had occasion to get out the stresses in girders of the bowstring form, the author was not satisfied with the common formulæ for the diagonal braces, which, owing to the difficulty of apportioning the stresses amongst five members meeting in one point, were to a large extent based on an assumption as to the course taken by the stresses. as far as he could ascertain it, the ordinary method was to assume that one set of diagonals, or those inclined, say, to the right-hand, acted at one time, and those inclined in the opposite direction at another time, and, in making the calculations, the apportionment of the stresses was effected by omitting one set. calculations made in this way give results which would justify the common method adopted in the construction of bowstring girders, viz., of bracing the verticals and leaving the diagonal unbraced; but an inspection of many existing examples of these bridges during the passing of the live load showed that there was something defective in them. the long unbraced ties vibrated considerably, and evidently got slack during a part of the time that the live load was passing over the bridge. in order to get some definite formulæ for these girders free from any assumed conditions as to the course taken by the stresses, or their apportionment amongst the several members meeting at each joint, the author adopted the following method, which, he believes, has not hitherto been used by engineers: let fig. represent a bowstring girder, the stresses in which it is desired to ascertain under the loads shown on it by the circles, the figures in the small circles representing the dead load per bay, and that in the large circle the total of live and dead load per bay of the main girders. a girder, fig. a, with parallel flanges, verticals, and diagonals, and depth equal to the length of one bay, was drawn with the same loading as the bowstring. the stresses in the flanges were taken out, as shown in the figure, keeping separate those caused by diagonals inclined to the left from those caused by diagonals inclined to the right. the vertical component of the stress in the end bay of the top flange of the bowstring girder, fig. , was, of course, equal to the pressure on the abutment, and the stress in the first bay of the bottom flange and the horizontal component of the stress in the first bay of the top flange was obtained by multiplying this pressure by the length of the bay and dividing by the length of the first vertical. the horizontal component of the stress in any other bay of the top or bottom flange of the bowstring girder--fig. --was found by adding together the product of the stress in the parallel flanged girder, caused by diagonals inclining to the right, divided by the depth of the bowstring girder at the left of the bay, and multiplied by the depth of the parallel flanged girder; and the product of the stress caused by diagonals inclining to the left divided by the depth of the bowstring girder at the right of the bay, multiplied by the depth of the parallel flanged girder. thus the horizontal component of the stress in d= _ _ | stress caused by diagonals length of right depth of parallel | | leaning to left. vertical. flanged girder. | | | + |_ . × / . × _| _ _ | stress caused by diagonals length of ver- depth of parallel | | leaning to right. tical to left. flanged girder. | | | |_ × / × _| = ; and the vertical component = horizontal component. length of bay. × / × ( . - . ) = . . in the same way the horizontal and vertical components of the stresses in each of the other bays of the flanges of the bowstring were found; and the stresses in the verticals and diagonals were found by addition, subtraction, and reduction. these calculations are shown on the table, fig b. the result of this is a complete set of stresses in all the members of the bowstring girder--see fig. --which produce a state of equilibrium at each point. the fact that this state of equilibrium is produced proves conclusively that the rule above described and thus applied, although possibly it may be considered empirical, results in the correct solution of the question, and that the stresses shown are actually those which the girder would have to sustain under the given position of the live load. figs. to inclusive show stresses arrived at in this manner for every position of the live load. an inspection of these diagrams shows: a. that there is no single instance of compression in a vertical member of the bowstring girder, b. that every one of the diagonals is subjected to compression at some point or other in the passage of the live load over the bridge, c. that the maximum horizontal component of the stresses in each of the diagonals is a constant quantity, not only for tension and compression, but for all the diagonals. the diagrams also show the following facts, which are, however, recognized in the common formulæ: d. the maximum stress in any vertical is equal to the sum of the amounts of the live and dead loads per bay of the girder. e. the maximum horizontal component of the stresses in any bay of the top flange is the same for each bay, and is equal to the maximum stress in the bottom flange. having taken out the stresses in several forms of bowstring girders, differing from each other in the proportion of depth to span, the number of bays in the girder, and the amounts and ratios of the live and dead loads, similar results were invariably found, and a consideration of the various sets of calculations resulted in the following empirical rule for the stresses in the diagonals: "the horizontal component of the greatest stress in any diagonal, which will be both compressive and tensile, and is the same for every diagonal brace in the girder, is equal to the amount of the live load per bay multiplied by the span of the girder, and divided by sixteen times the depth of girder at center." the following formulæ will give all the stresses in the bowstring girder, without the necessity of any diagrams, or basing any calculations on the assumed action of any of the members of the girders: let s = span of girder. d = depth at center. b = length of one bay. n = number of bays. l = length of any bay of top flange. l = length of any diagonal. w = dead load per bay of girder. w¹= live load per bay of girder. w = total load per bay of girder = w + w¹. then: s/b = n. bottom flange. wns/ d = maximum stress throughout. ( ) top flange.--in any bay the maximum stress = + wns/ d × l/b = + wln²/ d ( ) _verticals._--the maximum stress = -w. ( ) _diagonals._--the maximum stress is ± w¹ls/ db = ± w¹ln/ d ( ) these results show that the method generally adopted in the construction of bowstring girders is erroneous; and one consequence of the method is the observed looseness and rattling of the long embraced ties referred to at the commencement of the article during the passage of the live load; the fact being that they have at such times to sustain a compressive stress, which slightly buckles them, and sets them vibrating when they recover their original position. another necessity of the common method of construction is the use of an unnecessary quantity of metal in the diagonals; for, by leaving them unbraced, the set of diagonals which does act is subjected to exactly twice the stress which would be caused in it if the bridge was properly constructed. a comparison of the results of a set of calculations on the common plan with those given in this paper, shows at once that this is the case; for the ordinary system of calculation the stresses, in addition to showing compression in the verticals, gives exactly twice the amount of tension in the diagonals which they should have. fig. b. ________________________________________________________________________________ | top flange stresses. | stresses in diagonals. hor. ver. | | c= . × / . = + . = . |a = - =+ . = . | . × / . = |b = " " =- . = . \ | d > + . = . |c = - . - =+ . = . / | × / = |d = " " " =- . = . \ | e > + . = . |e = . - . - . =+ . = . / | . × / . = . |f = " " " =- . = . \ | f > + . = . |g = . - . - . =+ . = . / | × / = . |h = " " " =- . = . \ | g > + . = . |i = . - . - . =+ . = . / | . × / . = |j = " " " =- . = . \ | h > + . = . |k = . - . - . =+ . = . / | × / = . |l = " " " =- . = . \ | i > + . = . |m = . - . - . =+ . = . / | . × / . = . |n = " " " =+ . = . \ | j > + . = . |o = . - . - . =+ . = . / | × / = . |p = " " " =- . = . \ | k > + . = . | / | . × / . = . | | l= . × / . = + . = . | ____________________________________________|___________________________________ | _bottom flange stresses._ | _stresses in verticals._ | hor. | ver. m same as c = . | r = - = - . n " d = . | s = + . - . = - . o " e = . | t = + . - . = - . p " f = . | u = + . - . = - . q " g = . | v = + . - . = - . r " h = . | w = + . - . = - . s " i = . | x = + . - . = - . t " j = . | y = + . - . = - . u " k = . | z = + . = - . v " l = . | ____________________________________________|___________________________________ --_the engineer._ * * * * * a spring motor. an exhibition of a spring car motor was given at a recent date at the works of the united states spring motor construction company, twelfth street and montgomery avenue. as a practical illustration of the operation of the motor a large platform car, containing a number of invited guests and representatives of the press, was propelled on a track the length of the shop. (this was in .) the engine, if such it may be called, was of the size which is intended to be used on elevated railways. as constructed, the motor combines with a stationary shaft a series of drums, carrying springs, and arranged so that they can be brought into use singly or in pairs. each spring or section has sufficient capacity to run the car, and thus as one spring is used another is applied. there is a series of clutches by which the drums to which the springs are attached are connected, with a master wheel, which transmits through a train of wheels the power of the springs to the axles, of the truck wheels. the motor will be so constructed that it may be placed on a truck of the width of the cars at present in use, and will be nine feet long, with four traction wheels. it is proposed do away with the two front wheels and platform, so that the front of the car may rest on a spring to the truck. there will be an engine at each end of the road, which, it is calculated, will wind up the springs in at least two minutes' time. while the mere construction of such a working motor involved nothing new, the real problem involved consisted of the rolling of a piece of steel feet long, inches wide, and a quarter of an inch thick. another element was the coiling of this strip of steel preliminary to tempering. to temper it straight was to expose the grain to unnecessary strain when wound in a close coil. to overcome this was the most difficult part of the work. at the exhibition the inventor gave an illustration of the method which has been employed by the company. the strip of steel is slowly passed through a retort heated by the admixture of gas and air at the point of ignition in proportions to produce intense heat. when the strip has been brought to almost a white heat, it is passed between two rollers of the coiling machine. it is then subjected to a powerful blast of compressed air and sprays of water, so that six inches from the machine the steel is cold enough for the hand to be placed on it. after this operation the spring is complete and ready to be placed on the shaft. the use of the springs is said to be beyond estimate. they may be employed to operate passenger elevators, the springs being wound by a hand crank. it is understood that the french government has applied for them for running small yachts for harbor service. among the advantages claimed for this motor are its cheapness in first cost and in operating expenses. it is estimated that an engine of twenty-five horse power will be required at the station to wind the springs. if there be one at each end of the line, the cost for fuel, engineer, and interest will not exceed $ per week. this will answer for fifty or any additional number of cars. the company claims that by using twelve springs, each feet in length, an ordinary street car can be driven about twenty miles.--_phil. inquirer_. * * * * * casting chilled car wheels. we show herewith the method employed by the baltimore car wheel company in casting chilled wheels to prevent tread defects. the ordinary mode of pouring from the ladle into the hub part of the mould, and then letting the metal overpour down the brackets to the chill, produces cold shot, seams, etc. in the arrangement here shown the hub core, a, has a concave top, b, and the core seat, c, is convex, its center part being lower than the perimeter of the top of the core. figs. , , show the core, a, in the side elevation and in plain. fig. is a core point forming a space to connect the receiving chamber, e, above, with the mould by passageways, d d, formed in the side of the top of the core. the combined area of these passageways being less than that of the conduit, f, from the receiving chamber, the metal is skimmed of impurities, and the latter are retained in the receiving chamber, e. the entering metal flows first to the lower hub part at h h, thence by the sprue-ways, g g, to the lower rim part at j j, being again skimmed at the mouth of the sprue-ways. thus the rim fills as rapidly as the hub, and the metal is of a uniform and high temperature when it reaches the chill. [illustration: casting of car wheels.] in the wheels made by this firm, every alternate rib is connected with the rim, and runs off to nothing near the hub; the intermediate ribs are attached to the hub, and diminish in width toward the rim.--_jour. railway app._ * * * * * electricity and prestidigitation. the wonderful ease with which electricity adapts itself to the production of mechanical, calorific, and luminious effects at a distance, long ago gave rise to the idea of applying it to certain curious and amusing effects that simple minds willingly style _supernatural_, because of their powerlessness to find a satisfactory explanation of them. [illustration: fig. .--rapping and talking table. ] who has not seen, of old, robert houdin's heavy chest and robert houdin's magic drum? these two curious experiments are, as well known, founded upon the properties of electro-magnets. at present we shall make known two other arrangements, which are based upon the same action, and which, presenting old experiments under a new form, rejuvenate them by giving them another interest. the first apparatus (fig. ), which presents the appearance of an ordinary round center table, permits of reproducing at will the "spirit rappings" and sepulchral voice experiments. the table support contains a leclanche pile, of compact form, carefully hidden in the part that connects the three legs. the top of the table is in two parts, the lower of which is hollow, and the upper forms a cover three or four millimeters in thickness. in the center of the hollow part is placed a vertical electro-magnet, one of the wires of which communicates with one of the poles of the pile, and the other with a flat metallic circle glued to the cover of the table. beneath this circle, and at a slight distance from it, there is a toothed circle, f, connected with the other pole of the pile. when the table is pressed lightly upon, the cover bends and the flat circle touches the toothed one, closes the circuit of the pile upon the electro-magnet, which latter attracts its armature and produces a sharp blow. on raising the hand, the cover takes its initial position, breaks the circuit anew, and produces another sharp blow. upon running the hand lightly over the table, the cover is caused to bend successively over a certain portion of its circumference, contacts and breakages of the circuit are produced upon a certain number of the teeth, and the sharp blow is replaced by a quick succession of sounds, or a tremulous one, according to the skill of the medium whose business it is to interrogate the spirits. as the table contains within it all the mechanism that actuates it, it may be moved about without allowing the artifice to be suspected. [illustration: fig. .--electric insects.] the table may also be operated at a distance by employing conductors passing through the legs and under the carpet and communicating with a pile whose circuit is closed at an opportune moment by a confederate located in a neighboring apartment. finally, on substituting a small telephone receiver for the electro-magnet, and a microtelephone system for the ordinary pile, we shall convert the rapping spirits into talking ones. with a little exercise it will be easy for the confederate to transmit the conversation of the "spirits" in employing sepulchral tones to complete the illusion. fig. represents a device especially designed as a parlor ornament. when the plant is touched, the insects resting upon it immediately begin to flap their wings as if they desired to fly away. these insects are actuated by a leclanche pile hidden in the pot that contains the plant. the insect itself is nothing else than a mechanism analogous to that of an ordinary vibrating bell. the body forms the core of a straight electro-magnet, _c_, which is bent at right angles at its upper part, and in front of which is placed a small iron disk, _b_, forming the animal's head. this head is fixed upon a spring, like the armature of ordinary bells, and causes the wings to move to and fro when it is successively attracted and freed by the electro-magnet. the current is interrupted by means of a small vibrating device whose mode of operation may be easily understood by glancing at the section in fig. . the current enters the electro-magnet through a fine copper wire hidden in the leaves and connected with the positive pole of the pile. the negative pole is connected with the bottom of the pot. the wire from the vibrator of each insect reaches the bottom of the flower-pot, but does not touch it. a drop of mercury occupies the bottom of the pot, where it is free to move about. it results that if the pot be taken into the hand, the exceedingly mobile mercury will roll over the bottom and close the circuit successively on the different insects, and keep them in motion until the pot has been put down and the drop of mercury has become immovable. * * * * * portable electric safety lamps. one of the most difficult problems that daily presents itself in large cities is how to proceed without danger in the search for leakages in gas mains, or in attempts to save life in houses accidentally filled with explosive gases. the introduction of a flame into such places leads in the majority of cases to accidents whose consequences cannot be estimated. the reader will remember especially the explosion which occurred some time ago in st. denis street, paris, and which killed a considerable number of persons. it has, therefore, been but natural to think of the use of electricity, which gives a bright line without a flame, in order to allow life-saving corps and firemen to enter buildings filled with an explosive mixture, without any risk whatever. [illustration: fig. .--elevation (scale / ).] several electricians have proposed ingenious portable apparatus for this purpose, and, among these, mr. a. gerard, whose device we illustrate herewith. in this system the electric generator is stationary, and remains outside the building. this, along with all the rest of the apparatus, is mounted upon a carriage. the operator, instead of carrying a pile to feed the lamp, drags after him a very elastic cable containing the two conductors. this "ariadne's thread" easily follows all sinuosities, and adapts itself to all circumvolutions. the entire apparatus, being mounted upon a carriage, can be easily drawn to the place of accident like a fire engine. [illustration: fig. .--plan (scale / ).] _general description_.--fig. shows the carriage. in the center, over the axle, is mounted a dynamo-electric, machine, d, driven by a series of gear wheels that are revolved by winches, mm. upon the shaft, a, is fixed a hand wheel, v, designed to regulate the motion. in the forepart of the carriage are placed two windlasses, tt, permanently connected with the terminals of the dynamo. upon each of these is wound a cable formed of two conductors, insulated with caoutchouc and confined in the same sheath. each windlass is provided with five hundred feet of this cable, the extremity of which is attached to two lanterns each containing an incandescent lamp. these lanterns, are inclosed in boxes, bb, with double sides, and cross braced with springs so as to diminish shocks. under the windlass there is a case which is divided into two compartments, one of which contains tools and fittings, and the other, six carefully packed incandescent lamps, to be used in case of accident to the lanterns. at the rear end of the carriage there is a hinged bar, c, designed to support it at this point and give it greater stability during the maneuvers. the stability is further increased by chocking the wheels. [illustration: fig. .--hand lantern (scale / ).] _maneuver of the apparatus_.--the carriage, having reached the place of accident, is put in place, its rear end is supported by the bar, c, the wheels are chocked, and the winches are placed upon the dynamo gearing. two strong men selected for the purpose now seize the winches and begin to revolve them, and the lamps immediately light while in their boxes. another man, having opened the latter, takes out one of the lanterns and enters the dangerous place, dragging after him the elastic cable that unwinds from the windlass. two men are sufficient to turn the winches for five minutes; with a force of six men to relieve one another the apparatus may therefore be run continuously. [illustration: fig. .--pole lantern (scale / ).] the dynamo, which is of strong and simple construction, is inclosed in a cast iron drum, and is consequently protected against accident. with a power of kilogrammeters it furnishes a current of volts and amperes, which is more than sufficient to run two -candle incandescent lamps. the winches are removable, and are not put upon the shaft until the moment they are to be used. the windlasses, as above stated, are permanently connected with the terminals of the dynamos. the current is led to them through their bearings and journals. their shaft is in two pieces, insulated from one another. one extremity of the cable is attached to these two pieces, and the other to the lantern. each windlass is provided with a small winch that allows the cable to be wound up quickly. [illustration: fig. .--windlass (scale / ).] the two lanterns are different, on account of the unlike uses to which they are to be put. one of them is a hand-lamp that permits of making a quick preliminary exploration. the second is to be fixed by a socket beneath it to a pole that is placed along the shafts of the carriage. this lantern, upon being thrust into a chimney, shaft, or well, permits of a careful examination being made thereof. as the handle terminates in a point; it may be stuck into the ground, to give a light at a sufficient height to illuminate the surroundings. the hand lantern consists of a base, p, provided with three feet. at the top there is a threaded circle to which is attached a movable handle, k, that is screwed on to a ring, c. these three pieces, which are of bronze, are connected by steel braces, e, that form a protection for the glass, m. the lantern is closed above by a thick glass disk, g. the luminous rays are therefore capable of spreading in all directions. tight joints are formed at every point by rubber or leather washers. [illustration: fig. .--lantern box (scale / ).] in the center of the lantern is placed the incandescent lamp. this is held in a socket, and is provided with two armatures to which the platinum wires are soldered. two terminals, b, are affixed to the lamp socket. beneath the lantern there is a cylindrical box provided with a screw cap. in one side of this box there is a tubulure that gives passage to the electric cable whose conductors are fastened to the terminals. a conical rubber sleeve, r, incloses the cable, which is pressed by the screw cap, s. a special spring, y, attached at one end to the top of the lantern, and at the other to the cable, x, is designed to deaden the too sudden shocks that the lantern might be submitted to, and that would tend to pull out the cable. as a result of the peculiar arrangement of this lantern, the lamp is constantly surrounded with a certain quantity of air that would certainly suffice to consume the carbons in case of a breakage of the globe without allowing any lighted particles to escape to the exterior. besides, should the terminals become unscrewed, and should the conductors thus rendered free produce sparks, the latter would be prevented from reaching the exterior by reason of the absolute tightness of the box. in case the incandescent lamp should get broken, the only inconvenience that would attend the accident would be that the man who held the lantern would be for a moment in the dark. when he reached the carriage, it would be only necessary for him to take off the glass disk, take the broken lamp out of its socket, insert a new one, and then put the glass top on again.--_le génie civil_. * * * * * voltaic batteries containing solutions of ammonium chloride and zinc chloride can, according to the recent researches of m. onimus, be converted into dry piles by mixing these solutions with plaster of paris, and allowing the mixture to solidify. if mixtures of ferric oxide and manganese peroxide with plaster of paris are employed, the electromotive force is slightly higher than with plaster of paris alone; and when ferric oxide is used, the battery quickly regains its original strength on breaking the circuit. when the battery is exhausted, the solid plaster of paris has simply to be moistened again with the solution. * * * * * the electric discharge and spark photographed directly without an objective. the study of the form and color that electric discharges exhibit, according to the different ways in which they are produced, has already enticed a certain number of amateurs and scientists. every one knows the remarkable researches of the lamented th. du moncel on the induction spark, and during the course of which he, in , discovered that phenomenon of the electric efflux which has since been the object of important researches on the part of several physicists and chemists, among whom must be cited messrs. thenard, hautefeuille, and chapuis. twenty years ago, mr. bertin, who was then professor at the faculty of strassburg, and who was afterward subdirector of the normal school, was directing his researches upon the electric discharges produced by high tension apparatus, plate machines, and leyden jars. he thought, with reason, that, on account of its rapidity and complexity, a portion of the phenomenon must escape the eye of the observer, and so the idea occurred to him to photograph the discharge in order to afterward study its forms more at his leisure. we have recently had an opportunity of seeing a negative which was obtained by him at that epoch; but the photographic processes then in use probably did not allow him to obtain others that were as satisfactory, and he had given up this kind of study, when, last year, he had an opportunity of speaking of it to the well known manufacturer mr. f. ducretet, whom he induced to take it up and employ the new gelatino-bromide process. unfortunately, he died before these experiments were begun, and was unable to see the realization of his project. mr. ducretet did not abandon the idea, but constructed the necessary apparatus, and obtained the results that we now place before our readers. [illustration: fig .] his apparatus, which contains no photographic objective, consists of an oblong case, abcd, made of red glass and resting upon an ebonite table supported by one leg (fig. ). in the top of the case, as well as in the two sides, ad and bc, are apertures that are closed by ebonite cylinders through which slide, with slight friction, copper rods, hln. in the leg of the table there is a copper rack which may be maneuvered from the interior by a pinion, and which communicates electrically with a terminal, e. the upper part of this rack, which enters the glass case, is threaded, so that there may be affixed to it either a metallic or an insulating disk. the rods, hln, are likewise threaded, so that there may be affixed to their internal extremities balls, points, combs, and disks of metal or of insulating material at will. [illustration: fig .] in short, we have here a transparent box (impermeable to photogenic rays) into which electricity may be led by means of four conductors that are arranged two by two in a line with each other, or in perpendicular positions, and that may be made to approach or recede from one another by maneuvering them from the exterior. this very simple arrangement answers every requirement, and, upon placing a sensitized plate in the vicinity of the conductors, permits of photographing the electric discharge directly and, so to speak, before the eyes of the operator. as a source of electricity, use is made of a bichromate of potash battery of elements, capable of giving volts and amperes. the current from this battery is converted into a current of high tension by means of a strong induction coil capable of giving sparks more than eight inches in length. the discharge shown in fig. was obtained by means of a holtz machine. each experiment lasted less than a second. [illustration: fig. .] figs. and represent the efflux that occurred under; the following conditions: the disk, p, was of metal, and was connected with the negative pole of the induction coil; and upon it was laid the photographic plate with the sensitized film downward, and consequently touching the disk. this is what produced the opaque circle in the center. then the photographic plate was entirely covered with a thin ebonite plate, above which there was a second one supported by small wedges, so as to allow air to circulate between them. finally, upon this second ebonite plate there was placed another photographic plate, with its sensitized film upward and directly in contact with an upper metallic disk, and connected with the positive pole of the coil by the conductor, l. an inspection of figs. and shows that the, efflux does not possess the same form at the two poles. we remark at the positive pole a quite wide opaque circle surrounded by a sort of aureola composed of an infinite number of very delicate rays, while at the negative pole the aureola seems not to have been able to spread. we see, moreover, the same phenomenon in examining fig. (which represents the efflux obtained by means of a holtz machine), but this time in a horizontal direction. the photographic plate was here placed upon the non-conducting disk, p. as the sensitized film was upward, it was put in contact with the balls at the extremity of the conductors, h and n. [illustration: fig. .] it will be seen here again that the efflux spreads out widely at the positive pole, while it is contracted at the other. the conducting balls were spaced . inch apart. a spark leaped from one to the other at the moment the current was being interrupted. in fig. we are enabled to study with more ease a spark obtained with nearly the same arrangement. the balls, h and n, did not here rest directly upon the sensitized film, but upon two small sheets of tin cemented to the extremities of the plate at . inch apart. in addition, the source employed was not the holtz machine, but the pile with induction coil. two nearly parallel sparks were obtained. it will be seen that these are very complex. each of them seems to be formed of four lines of different sizes, entangled with one another and presenting different sinuosities. aside from this, the plate is traversed for a space of . of an inch by curved lines running from one pole to the other, and exhibiting numerous sinuosities. [illustration: fig. .] fig. represents a discharge that occurred under the following circumstances: the disk, p, being metallic and connected with one of the poles, there was placed upon it a thin ebonite plate of the same dimensions as the photographic one, and then the latter with the sensitized pellicle upward. finally, the pellicle was put in contact with the upper conductor, l, which terminated in a ball and was connected with the other pole of the induction coil. it will be seen that, despite the two dielectrics (ebonite and glass) interposed, and the opacity of one of them, the efflux that occurred around the disk, p, is quite sharply reproduced upon the sensitized plate by a circle like that which we observed in figs. and . it will be seen, besides, that an infinite number of ramifications in every direction has been produced around the ball, and we can follow the travel of the spark that leaped between the ball and disk in two directions situated in the prolongation of one another. under the two principal and clearly marked lines that this spark made there are seen two other, very pale and much wider ones, that present no sinuosities parallel with the first. the results of these experiments are very curious. the position of the plates was varied in different ways, as was also the form of the conductors. we have spoken of those only that appear to us to present the most interest. unfortunately, notwithstanding the skill of the engraver, it is impossible to render with accuracy all the details that are seen upon examining the negative. the proofs that have been printed upon paper present much less sharpness than the negative, for there are certain parts of the figures on the glass that do not show in the print. [illustration: fig. .] we have been content here to make known the results obtained, without drawing any conclusions from them. it is to be hoped that these experiments, which can be easily repeated by means of the apparatus described above, will be repeated and discussed by electricians, and that they will contribute toward making known to us the nature of the mysterious agent that will give its name to our era.--_g. mareschal, in la lumiere electrique._ * * * * * the true constant of gravity. many of the readers of this journal may like to participate in the discussion of the following proposition. the statement is this: the space through which a body, near the surface of the earth, at mean latitude, _in vacuo_, descends by virtue of the accelerating force of gravity in / of an hour is precisely , geometric inches = geometric cubits = the side of a square geometric acre. [the geometric inch is taken, in accordance with the view of sir john herschel, at / , , , of twice the polar axis of the earth, and equals - / english inches very nearly.] the strict decimal relation of the proposition is shown by the following table. it has been tested by clairaut's theorem, and by other existing expressions, and has been found to agree, far within the probable limits of errors in observation, with the most approved values of the constant. in fact, it is contained in the existing expressions; but the _decimal_ relation does not appear unless we state the unit of linear measure as a decimal of the earth's semi-polar axis, and, at the same time, divide the circle, both for time and for general purposes, _geometrically, i.e._, by strict decimalization upon the hour-angle. a mathematical reason underlies the proposition. time in acquired squares total ratio of descent in thousandths velocity, of the descent, spaces, each successive of an hour. cubits. time. cubits. interval of intervals, time. cubits. , , , , , , , , , , , , , , , , , , so that-- cubits. acre sides. in / , of an hour, the total descent = = / in / of an hour, the total descent = = in / of an hour, the total descent = , = and so on, in strict _decimal_ relation with the earth's semi-polar axis. a two-fold reason why the constant for latitude ° is vastly better than any other, is in its having this simple relation with the semi-axis, and at the same time a less complex way of applying the correction for latitude. jacob m. clark. new york, february, . * * * * * origin of thunderstorms. at the recent congress of german medical men and physicists, dr. s. hoppe, of hamburg, read a paper in which he sought to show that the electricity of thunderstorms is generated by the friction of vapor particles generated by the evaporation of water. this opinion was strengthened by several experiments in which compressed cold air was allowed to rush into a copper vessel containing warm moist air, thus generating a large amount of electricity. he concludes that the rise of a column of warm moist air into the colder atmosphere above will be followed by a thunderstorm if it acquires sufficient velocity to prevent neutralization of the electricity generated by the friction of the air. hence, in his opinion, open districts denuded of forests are more liable to thunderstorms than wooded regions, where the trees forbid the rise of humid air currents. * * * * * improvised toys. do our readers remember all those ingenious toys which our mothers and sisters improvised in order to amuse us? we took a walk into the country, and our eldest sister or our mother picked a wild poppy, turned its red petals back and encircled them with a thread, and stuck a sprig of grass into the seed vessel to represent a headdress of feathers. here was a fresh and pretty doll (fig. ). another day it was the season of lilacs. the children gathered branches by the armful, and from these the mother picked off the flowers and strung them one by one with a needle. here was a bracelet or a necklace. an acorn was picked up in the woods, the mother carved it with a pen-knife, and behold a basket. from a nutshell she made a boat, and from a green almond a rabbit. sometimes she carved the rabbit's ears out of the almond itself, but in most cases they were made from a pretty rose-colored radish. [illustration: fig. .--doll made of a wild poppy.] do you remember the cork from which, by the aid of a few long needles for bars, an ingenious fly-cage was formed? and the castle of cards, four, five, and eight stories high? and then those famous card tents in a row, that fell one after another when the first one in the line was overturned? [illustration: fig. .--hygrometric doll; its dress colored with chloride of cobalt.] how we passed the evenings with our eyes fixed upon our mothers, who patiently, with their skillful scissors, cut horses and dogs out of old white, red, and blue cards! and how many plays, without costing a cent, served to amuse the children by exercising their ingenuity! the mother marked at hazard five dots upon a sheet of paper. the question was to draw a man, one of the dots showing the place of the head and the other four the feet and hands. [illustration: fig. .--old man made of lobster's claws.] when the dessert was brought upon the table, it became a question of manufacturing a head out of an orange. that is not very difficult; two holes for the eyes, a large slit for the mouth, and nothing easier than to simulate the teeth and nose. the head was placed upon a napkin stretched over the top of a champagne glass. this was one of our great amusements. the napkin was drawn ultimately to the right and left, and this moved the head and caused it to assume most comical positions. but what caused irresistible laughter was when a sly hand pressed the head and made it open its mouth wide. and then what pigs we manufactured with a lemon perched upon four matches! [illustration: fig. .--crocus flowering in a perforated pot.] without mentioning chinese shadows, how many cheap amusements there are that can be varied to infinity merely by various combinations of the fingers interlocked in diverse manners! [illustration: fig. .-- . paper cross. . method of making the cross. . rabbits made of green almonds. . basket made of sedges. . acorn basket. . fly-cage made of a cork.] all such amusements were much in vogue in former times, but we are assured that to-day mothers are less conversant with these curious and droll inventions, which were once transmitted like the tales of mother goose. they buy playthings for their children at great expense, and allow the latter to amuse themselves all by themselves. the toy paid for and given, the child is no longer in their mind. those mothers who have preserved the traditions of these little pastimes, and know how to skillfully vary them, find therein so many resources for amusing their children. then it is so pleasant to see the eyes of the latter eagerly fixed upon the scissors, and to hear their exclamations of pleasure and their fresh laughter when the paper is transformed under expert fingers into a boat, house, or what not! [illustration: fig. .--the lesson in drawing.--an illustrated five-spot of hearts.] it has required millions of mothers and nurses to put their wits to work to amuse their children in order to form that collection of charming combinations that at present constitutes a sort of science. mr. gaston tissandier not long ago conceived the happy idea of bringing together in an illustrated volume a description of some of these improvised toys and amusing plays, and it is from this that the accompanying illustrations (which sufficiently explain themselves) are taken. * * * * * the Æolian harp. the Æolian harp is a musical instrument which is set in action by the wind. the instrument, which is not very well known, is yet very curious, and at the request of some of our readers we shall herewith give a description of it. [illustration: fig. .--kircher's Æolian harp.] according to a generally credited opinion, it is to father kircher, who devised so many ingenious machines in the seventeenth century, that we owe the first systematically constructed model of an Æolian harp. we must add, however, that the fact of the spontaneous resonance of certain musical instruments when exposed to a current of air had struck the observers of nature in times of remotest antiquity. without dwelling upon the history of the Æolian harp, we may say that in modern times this instrument has been especially constructed in england, scotland, germany, and alsace. the Æolian harp of the castle of baden baden, and those of the four turrets of strassburg cathedral are celebrated. [illustration: fig. .--frost & kastner's improved Æolian harp.] we shall first describe kircher's harp, which this jesuit savant constructed according to an observation made by porta in . the instrument consists of a rectangular box (fig. ), the sounding board of which, containing rose-shaped apertures, is provided with a certain number of strings stretched over two bridges and fastened to pegs at the extremities. this box carries a ring that serves for suspending it. kircher recommends that the box be made of very sonorous fir wood, like that employed in the construction of stringed instruments. he would have it . meters in length, . meter in width, and . meter in height, and would provide it with fifteen catgut strings, tuned, not like those of other instruments to the third, fourth, or fifth, but all in unison or to the octave, in order, says he, that its sound shall be very harmonious. the experiments of kircher showed him the necessity of employing a sort of concentrator in order to increase the force of the wind, and to obtain all the advantage possible from the current of air that was directed against the strings. the place where the instrument is located should not, according to him, be exposed to the open air, but must be a closed one. the air, nevertheless, must have free access to it on both sides of the harp. the force of the wind may be concentrated upon such a point in different ways; either, for example, by means of conical channels, or spiral ones like those used for causing sounds to reach the interior of a house from a more elevated place, or by means of a sort of doors. these latter, two in number, are adapted to a kind of receptacle made of boards and presenting the appearance of a small closet. in the back part of this receptacle there is a slit, and in front of this the harp is hung in a slightly oblique position. the whole posterior portion of the apparatus must be situated in the apartment, while the doors must remain outside the window (fig. i). in later times the Æolian harp has been improved by messrs. frost and kastner, whose apparatus is represented in fig. . it consists of a rectangular box with two sounding boards, each provided with eight catgut strings. in order to limit the current of air and to bring it with more force against the strings, two wings are adapted near the thin surfaces opposed to the wind, so that the current may reach each group of cords on passing through the narrow aperture between the obliquely inclined wing and the body of the instrument. the dimensions of the resonant box are as follows: height, . meters; width, . meter; and thickness, . meter. distance between the two bridges, or length of the sonorous portion of the cords, about meter; width of the wings, . meter. distance between the sounding board and the wings, . meter. inclination of the wings, degrees. [illustration: fig. .--Æolian harp in the old castle of baden baden.] the celebrated Æolian harps of the old castle of baden baden are entirely different, and merit description. one of them (fig. ) is formed of a resonant box, the construction of which differs from that of Æolian harps with a rectangular box, in that it is prolonged beyond the place occupied by the strings, and is rounded off behind. in the opposite side there are two long and narrow apertures. to prevent the apparatus from being injured by the weather, it is inclosed in a sort of case occupying the recess of the window in the old ruined castle in which it is exposed. behind the harp there is a wire lattice door, the purpose of which seems to be to protect the instrument against the attempts of robbers or the indiscreet contact of tourists. we annex to the general view of the instrument a front and profile plan (fig. ). the Æolian harp has often inspired both writers of prose and poetry. chateaubriand, in _les natchez_, compares its sounds to the magic concerts that the celestial vaults resound. without attributing such effects to the instrument, it must be admitted that it possesses remarkable properties, which act upon the nervous system and cause very different impressions, according to the temperament of those who listen to its accords. [illustration: fig. .--plan of the baden baden instrument.] hector berlioz, in his _voyage musicale en italie_, has given as follows the curious effects that an Æolian harp produced upon his lively and impassioned imagination: "on one of those gloomy days that sadden the end of the year, listen, while reading ossian, to the fantastic harmony of an Æolian harp swinging at the top of a tree deprived of verdure, and i defy you not to experience a profound feeling of sadness and of _abandon_, and a vague and infinite desire for another existence." an english physician, dr. j.m. cox, in his practical _observations_ upon dementia, asserts that unfortunate lunatics have been seen whose sensitiveness was such that ordinary means of cure had to be given up with them, but who were instantly calmed by the sweet and varied accords of an Æolian harp. other observers narrate that they have heard the efficacy of aeolian sounds spoken of in scotland for producing sleep. telegraph wires are often, under the influence of the winds, submitted to vibrations which reproduce the phenomena of the aeolian harp. the electric telegraph, which, before the construction of the kehl bridge, directly traversed the rhine, very frequently resounded, and the observer who placed his ear against the poles on the bank of the river was enabled to hear something like a far-off sound of bells.--_la nature_. * * * * * physics without apparatus. manufacture of illuminating gas. [illustration: fig. .--production of illuminating gas.] burn a piece of paper of about the size of the hand upon a clean porcelain plate, and this will serve to show the phenomena of carbonization and the formation of empyreumatic products under the action of heat. under the burned paper there will be found a yellowish deposit which sticks to the fingers, and which consists of oil of paper produced by distillation. an idea of the production of illuminating gas through the distillation of coal may be easily given by means a single clay pipe. upon filling the bowl of this with fragments of coal, closing the opening with clay, and, after the latter is dry, placing the bowl in a coal fire so that the stem shall project, gas will soon be observed issuing from, the latter, and, when lighted, will give a very bright flame. if the pipe seems to be a little too costly, recourse maybe had to a large piece of wrapping paper rolled into the form of a cornucopia, and held in the left hand by means of the pointed end. if, after an aperture has been made in this near the point, the base be lighted, the heat developed by the flame will produce a sort of distillation of the organic matter of the paper, and the empyreumatic and gaseous products will rise in the cone, and make their exit through the orifice, where they may be lighted with a match (fig. ). it goes without saying that this experiment lasts but a few seconds; but, as short as this period is, it is sufficient to give a demonstration of the production of illuminating gas through the distillation of organic matters. care should be taken not to set anything on fire while performing it, and it is well to operate over a pavement, and far from any inflammable materials. elasticity of bodies. [illustration: fig. .--experiment on the elasticity of bodies.] mould a piece of fresh bread with the fingers so as to give it the size and shape shown in fig. . if this object be placed upon a wooden table, and a hard blow be given it with the fist, it will be found impossible to put it permanently out of shape. however hard be the blow, the elastic material, although flattened for an instant, will always resume its original form. if the object be thrown on the floor with all one's might, the result will be the same; its elasticity will always cause it to spring back to its original form. the experiment will only succeed when the bread that is used is very fresh and soft. * * * * * scientific amusements. _the dance of the electrified puppets_.--we have already pointed out a means of obtaining electrical manifestations without recourse to a machine, and shall now describe a very easily performed experiment--the dance of the electrified puppets. [illustration: fig. .--dance of the electrified puppets.] procure a pane of glass about inches in width and in length, and support it between two large books, as shown in fig. . the glass must be inserted in the books in such a way that it shall be an inch and a fraction above the surface of the table. then, with a pair of scissors, cut out of a piece of tissue-paper a number of figures, such as men, women, clowns, frogs, etc. these little figures must not exceed three-quarters of an inch in length. we show some of actual size in fig. . they may be cut out of papers of different colors, so as to give variety to the scene. after they are prepared they are to be placed in the ball-room, that is to say, in the space between the books, glass, and table. they should be laid flat upon the table, and alongside of one another. now rub the upper surface of the glass vigorously with a piece of silk or woolen, and, in a few instants, the figures will be attracted by the electricity, and suddenly stand up straight and jump up to the transparent ceiling of their ball-room. then they will be repelled, and again attracted, and thus keep up a lively dance. when the rubbing is stopped, the dance continues spontaneously for some little time, and even the contact of the hand suffices to animate the figures. in order that this experiment shall prove a success, the glass used must be very dry, as well as the fabric with which it is rubbed. if the latter be warmed, the manifestation will be more rapid and energetic. silk answers better than woolen. [illustration: fig. .--silhouette portraits.] _silhouette portraits_.--take a large sheet of paper, black on one side and white on the other, and affix it to the wall, white surface outward, by means of pins or tacks. place a very bright light upon the table, at a proper distance, and allow the person whose portrait it is desired to form to stand between it and the wall (fig. ). then, with a pencil, draw the outlines of the shadow projected. while this is being done, it is very necessary that the subject shall keep perfectly immovable. when the outlines are sketched, remove the paper from the wall and cut out the portrait. after this, all that remains to be done is to turn the portrait over and paste it to a sheet of white paper. the silhouette is profiled in black, and if the operation be skillfully performed, the resemblance will be perfect.--_la nature_. * * * * * how to break a cord with the hands. our readers have often seen grocers' clerks or employes of business houses break the string with which they had tied up a package, by seizing it with the hands, bringing the latter close together, and then suddenly separating them with a quick movement. if it be thought that this quick motion is sufficient, let any one try it, and he will merely cut his hands without breaking the string, provided the latter has some little strength. in order to succeed, the cord must be arranged in a certain manner, as we shall explain. [illustration: mode of breaking a cord with the hands.] the cord to be broken is placed upon the left hand, and one of its ends is passed over the other in such a way as to form a cross, and the end forming the shorter part of the cross is wound around the fingers (it should be left long enough to make several turns). the other end is then turned back and wound around the right hand, so as to leave a space of about eighteen inches between the latter and the left hand. if these directions are properly followed, the string should have the form of a y in the middle of the hand, as shown in the lower figure of the accompanying engraving. it is only necessary after this to close the hand, after seeing that the y is very taut, and to seize the cord with the other hand, as shown in the upper figure. this done, the two hands are brought together and then suddenly separated so as to give a quick pull on the point of junction of the y-shaped branches, which form a true knife. it will be readily seen that as the cord is broken suddenly the shock does not have time to transmit itself to the hands. this is an interesting demonstration of the principle of inertia. * * * * * an aquatic velocipede for duck hunting. the curious apparatus that we represent in fig. , from an old english engraving of , is an aquatic velocipede which was utilized with success during the entire winter of . an amateur employed it for hunting ducks upon the numerous streams of lincolnshire, and, as it appears, obtained very good results from it. the device is very ingenious. it consists of three floats of from , to , cubic inches capacity, made of copper or tin plate. these are full of air, and must be perfectly tight. they are held together by arched iron rods, as shown in the cut, so as to form the three angles of an isosceles triangle. these rods are provided in the center with a saddle for the velocipedist to sit upon. the apparatus floats upon the water and sustains the hunter, whose feet are provided with quite short paddles, by means of which he navigates, and steers himself. [illustration: fig. .--an aquatic velocipede of .] the amusing engraving of this velocipede, which is mentioned under the name of the _aquatic tripod_, puts us in mind of another document of the same kind that we have seen in the gallery of prints of the national library. it is a naively drawn lithograph representing a trial of velocipedes in the luxembourg garden, at paris, in . in fig. we give a reduced copy of it. it will be seen that in velocipedes were made of wood and were provided with two wheels--one in front, and the other behind. the propelling was done by alternately placing the feet on the ground. [illustration: fig. .--a trial of velocipedes in .] * * * * * a sunshine recorder. the apparatus is of simple construction. it consists of a glass sphere silvered inside and placed before the lens of a camera, the axis of the instrument being placed parallel to the polar axis of the earth. the whole arrangement will be readily understood by an inspection of fig. . the light from the sun is reflected from the globe, and some of it, passing through the lens, forms an image on a piece of prepared paper within the camera. in consequence of the rotation of the earth, the image describes an arc of a circle on the paper, and when the sun is obscured, this arc is necessarily discontinuous. the image is not a point, but a line, and in certain relative positions of the sphere, lens, and paper, the line is radial and very thin, so that the obscuration of the sun for only one minute is indicated by a weakening of the image. [illustration: fig. .] in the actual apparatus the sphere is an ordinary round-bottomed flask about mm. in diameter, and the lens a simple double convex lens of about mm. focal length. the sensitive paper employed is the ordinary ferro-prussiate now so much used by engineers for copying tracings. this was selected in consequence of the ease with which the impression is fixed, for the paper merely requires to be washed in a stream of water for six minutes, no chemicals being necessary. when the paper is dry, radial lines containing between them angles of ° are drawn from the center of the circular impression, and thus give the hour scale, the time of apparent noon being of course given by a line passing through the plan of the meridian. fig. is a copy of the record of june , ; in the morning the sun shone brightly, toward noon clouds began to form, and in the afternoon the sky was hazy. the field in which the instrument is placed is surrounded by trees, so the ends of the trace are cut off sharply by shadows. [illustration: fig. .] with the alteration of declination of the sun, the light entering the camera is reflected from different portions of the sphere, and an alteration of the position of the focus results. this may be corrected in three ways; by moving ( ) the paper, ( ) the lens, or ( ) the sphere. in the present apparatus the first method has been adopted, and now the camera is about twice as long as it was in june. as a consequence, the circular image is enlarged, and the light therefore weakened, and that at a time of year when it can least be spared. if the focus is altered by moving the lens, the winter circle is small and the summer circle is much larger. this would perhaps be too much to the advantage of the winter sun. if, however, the lens and paper are maintained at a constant distance, and the sphere alone moved, the circles are more nearly of the same diameter throughout the year, the winter one still remaining the smallest. this seems, therefore, to be the most advantageous arrangement, and the one that will be adopted in future. it may be possible also to find positions for the sphere, lens, and paper such that the intensity of the image is a true measure of the intensity of the sun's light; at present, however, this has not been done, the want of sunlight and the press of official work having prevented the carrying out of the necessary experiments. a more sensitive paper might also be used with advantage, and in observatories where photographic processes are carried on daily there would be no difficulty on this score, but my principal object was to devise some economical instrument requiring only easy manipulation, so that at a considerable number of places the instruments might be set up, giving a more useful average of the duration of sunshine than can be obtained from only a few stations. the instrument also gives a record when the sun is shining through light clouds; in this case the image is somewhat blurred and naturally weakened, and it may be difficult or impossible to employ any scale for measuring the intensity under such conditions, but it must be remembered that, even when the sun is shining in this imperfect manner, it is really doing work on the vegetation of the earth, and deserves to be recorded. it may be well to say that the instrument is in no way protected. some friends, whose opinion i highly value, urged me to patent it; but as i strongly hold the view that the work of all students of science should be given freely to the world, the apparatus was described at the physical society a few hours after the advice was given, lest the greed of filthy lucre should, on further deliberation, cause me to act contrary to my principles.--_herbert mcleod, nature_. * * * * * skeleton of a bear found in a cave in styria, austria. in the limestone mountains of the austrian alpine countries, numerous large caverns and caves are found, some of which are several miles long. they have been formed by the raising, lowering, and sliding of the layers of sand, or washed out by the stream. in one of these caverns near peggau, in styria, austria, the skeleton of a bear (_ursus spelaeus_) and the skull of another bear of the same kind were found, both of which are shown in the annexed cut taken from the _illustrirte zeitung_, the detached skull being placed on a board. the place in which these bones were found had never been reached before, as the skeleton was covered by a layer, from four to six inches thick, of stalagmites, which in turn rested on a layer of pieces or chips of bones and carbonate of lime, sand, etc. the bones of the skeleton were scattered over a space about eight square yards, and it required several days' work to remove the layers from the bones by means of a mallet and chisel and to give the bones, etc., a presentable appearance. [illustration: skeleton of a bear found in a cave in styria, austria.] the skull on the board is of especial interest on account of the beautiful crystals of calcareous spar, which are from / to / of an inch long, and are formed on the inner sides of the skull. the skull is - / in. wide between the fangs and - / in. wide at the forehead, whereas the skull of the skeleton is only - / in. wide at the fangs and - / in. wide at the forehead. the skull of the skeleton is in. long. the small white object on the board supporting the detached skull represents the skull of an ordinary cat, thus giving an idea of the enormous size of the bear's skull. the skeleton is ft. in. high, and is one of the largest and most complete that has been found. * * * * * the hardness of metals. the german _verein zur bedförderung des gewerbefleisses_ offers the following, among other prizes, for essays on technical subjects: one thousand marks _(£ )_ for a comparative examination of the various methods hitherto used for determination of the hardness of metals, with an exposition of their sources of error and limits of accuracy. it is stated, as a reason for offering the prize, that the methods for making the required tests are but yet little developed, and that no thorough comparison has yet been made of the various methods. the hardness of metals and alloys being a very important factor in several processes, a really good method of determination is highly desirable. three thousand marks (£ ) for the best essay on the resistance to pressure of iron work in buildings, at increased temperatures. it appears that after a certain fire in a manufactory at berlin, the police authorities issued notices concerning the use of cast-iron columns in high buildings, and that these notices encountered great opposition in many quarters, as it was considered that neither practice nor theory had yet shown any proof that cast iron is less trustworthy than wrought iron in cases of fire. * * * * * a brilliant black varnish for iron, stone, or wood can be made by thoroughly incorporating ivory black with common shellac varnish. the mixture should be laid on very thin. but ordinary coal tar varnish will serve the same purpose in most cases quite as well, and it is not nearly so expensive. * * * * * steam yachts. although the racing of steam yachts as a recognized sport has not made the progress that was at one time expected, yet the owner and crew of a crack vessel will take as much interest in her performance as those belonging to a sailing yacht, and hate to be passed quite as badly. in this way many informal matches come off, and some of these are for considerable distances. the _field_ contains a notice of a run recently made from plymouth breakwater to gibraltar, by the juno, owned by mr. frank millan, and the queen of palmyra, in which the former beat the latter by only five minutes. the time occupied was four days twenty hours, a fair, though not extraordinary, performance for vessels of this size. the juno has always been considered a slow boat, but has been much improved lately by new machinery, which has been put in her by messrs. day, summers & co. her best performance on the run was knots in ¾ hours. the marchesa, mr. c.t. kettlewell, started from plymouth on the d of last december, and made the run to gibraltar in four days seventeen hours; while the amy, starting on december , was four days thirteen hours from cowes to gibraltar. * * * * * a catalogue, containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . , stitched in paper, or $ . , bound in stiff covers. combined rates--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway, new york, n.y. * * * * * patents. in connection with the scientific american, messrs. munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats. trade marks, their costs, and how procured. address munn & co., broadway, new york. branch office, cor. f and th sts., washington, d.c. proofreading team at www.pgdp.net [illustration] scientific american supplement no. new york, september , . scientific american supplement. vol. xxxii, no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. astronomy.--the story of the universe.--by dr. william huggins.--a valuable account of modern views of the formation of the universe, and of modern methods of studying the problem.-- illustration. ii. electricity.--the production of hydrogen and oxygen through the electrolysis of water.--a valuable paper on the electrolysis of water on a large scale, with apparatus employed therefor.-- illustrations. iii. mechanical engineering.--an english steam fire engine.--a light fire engine built for east indian service.-- illustration. iv. medicine and hygiene.--a case of drowning, with resuscitation.--by f.a. burrall, m.d.--a full account of a remarkable case of resuscitation from drowning, with full details of treatment. v. metallurgy.--how gas cylinders are made.--the manufacture of cylinders for highly compressed gases, a comparatively new and growing industry.-- illustrations. refining silver bullion.--the gutzkow process in refining silver bullion with sulphuric acid.-- illustration. the treatment of refractory ores.--a new process for the extraction of metal from refractory ore.-- illustration. weldless steel chains.--an exhaustive examination of this curious process, and very full illustrations.-- illustrations. vi. meteorology.--climatic changes in the southern hemisphere. --by c.a.m. taber.--causes of the climatic changes the southern hemisphere has undergone. vii. military tactics.--the system of military dove cotes in europe.--continuation of this paper, treating of the pigeon service in france, germany, and italy. viii. naval engineering.--the isle of man twin screw steamer tynwald.--a high speed steamer, with a steady sea-going speed of between and knots.-- illustrations. ix. technology.--ammonia.--the manufacture of ammoniacal gas for technical uses.--full details of its production. musical instruments.--their construction and capabilities.--by a.j. hipkins.--second installment of this highly interesting series of lectures treating of different kinds of instruments. note on refrigerating apparatus. sheet glass from molten metal.--the method of making sheets of glass from the molten material and manufacture of metal plates by the same method. x. veterinary science.--historical development of the horseshoe.--by district veterinarian zippelius.--very curious investigation of the development of the horseshoe.-- illustrations. * * * * * the production of hydrogen and oxygen through the electrolysis of water. all attempts to prepare gaseous fluids industrially were premature as long as there were no means of carrying them under a sufficiently diminished volume. for a few years past, the trade has been delivering steel cylinders that permit of storing, without the least danger, a gas under a pressure of from to atmospheres. the problem of delivery without pipe laying having been sufficiently solved, that of the industrial production of gases could be confronted in its turn. liquefied sulphurous acid, chloride of methyl, and carbonic acid have been successively delivered, to commerce. the carbonic acid is now being used right along in laboratories for the production of an intense coldness, through its expansion. oxygen and nitrogen, prepared by chemical processes, soon followed, and now the industrial electrolysis of water is about to permit of the delivery, in the same manner, of very pure oxygen and hydrogen at a price within one's reach. before describing the processes employed in this preparation, we must answer a question that many of our readers might be led to ask us, and that is, what can these gases be used for? we shall try to explain. a prime and important application of pure hydrogen is that of inflating balloons. illuminating gas, which is usually employed for want of something better, is sensibly denser than hydrogen and possesses less ascensional force, whence the necessity of lightening the balloon or of increasing its volume. such inconveniences become serious with dirigible balloons, whose surface, on the contrary, it is necessary to diminish as much as possible. when the increasing interest taken in aerostation at paris was observed, an assured annual output of some hundreds of cubic meters of eras for the sole use of balloons was foreseen, the adoption of pure hydrogen being only a question of the net cost. pure or slightly carbureted hydrogen is capable of being substituted to advantage for coal gas for heating or lighting. such an application is doubtless somewhat premature, but we shall see that it has already got out of the domain of utopia. finally the oxyhydrogen blowpipe, which is indispensable for the treatment of very refractory metals, consumes large quantities of hydrogen and oxygen. for a few years past, oxygen has been employed in therapeutics; it is found in commerce either in a gaseous state or in solution in water (in siphons); it notably relieves persons afflicted with asthma or depression; and the use of it is recommended in the treatment of albumenuria. does it cure, or at least does it contribute to cure, anæmia, that terrible affection of large cities, and the prime source of so many other troubles? here the opinions of physicians and physiologists are divided, and we limit ourselves to a mention of the question without discussing it. only fifteen years ago it would have been folly to desire to obtain remunerative results through the electrolysis of water. such research was subordinated to the industrial production of electric energy. we shall not endeavor to establish the priority of the experiments and discoveries. the question was in the air, and was taken up almost simultaneously by three able experimenters--a russian physicist, prof. latchinof, of st. petersburg, dr. d'arsonval, the learned professor of the college of france, and commandant renard, director of the military establishment of aerostation at chalais. mr. d'arsonval collected oxygen for experiments in physiology, while commandant renard naturally directed his attention to the production of pure hydrogen. the solutions of the question are, in fact, alike in principle, and yet they have been developed in a very different manner, and we believe that commandant renard's process is the completest from an industrial standpoint. we shall give an account of it from a communication made by this eminent military engineer, some time ago, to the french society of physics. _transformations of the voltameter._--in a laboratory, it is of no consequence whether a liter of hydrogen costs a centime or a franc. so long as it is a question of a few liters, one may, at his ease, waste his energy and employ costly substances. the internal resistance of a voltameter and the cost of platinum electrodes of a few grammes should not arrest the physicist in an experiment; but, in a production on a large scale, it is necessary to decrease the resistance of the liquid column to as great a degree as possible--that is to say, to increase its section and diminish its thickness. the first condition leads to a suppression of the platinum, and the second necessitates the use of new principles in the construction of the voltameter. a laboratory voltameter consists either of a u-shaped tube or of a trough in which the electrodes are covered by bell glasses (fig. , a and b). in either case, the electric current must follow a tortuous and narrow path, in order to pass from one electrode to the other, while, if the electrodes be left entirely free in the bath, the gases, rising in a spreading form, will mix at a certain height. it is necessary to separate them by a partition (fig. , c). if this is isolating and impermeable, there will be no interest in raising the electrodes sensibly above its lower edge. now, the nearer together the electrodes are, the more it is necessary to lower the partition. the extension of the electrodes and the bringing of them together is the knotty part of the question. this will be shown by a very simple calculation. [illustration: fig. .--a, b, commonest forms of laboratory voltameters. c, diagram showing ascent of bubbles in a voltameter.] the visible electrolysis of water begins at an e.m.f. of about . v. below this there is no disengagement of bubbles. if the e.m.f. be increased at the terminals of the voltameter, the current (and consequently the production of gas) will become proportional to the excess of the value over . v; but, at the same time, the current will heat the circuit--that is to say, will produce a superfluous work, and there will be waste. at . v the rendering is at its maximum, but the useful effect is _nil_. in order to make an advantageous use of the instruments, it is necessary to admit a certain loss of energy, so much the less, moreover, in proportion as the voltameters cost less; and as the saving is to be effected in the current, rather than in the apparatus, we may admit the use of three volts as a good proportion--that is to say, a loss of about half the disposable energy. under such conditions, a voltameter having an internal resistance of ohm produces . liter of hydrogen per hour, while it will disengage . liters if its resistance be but . of an ohm. it is true that, in this case, the current would be in the neighborhood of , amperes. laboratory voltameters frequently have a resistance of a hundred ohms; it would require a million in derivation to produce the same effect. the specific resistance of the solutions that can be employed in the production of gases by electrolysis is, in round numbers, twenty thousand times greater than that of mercury. in order to obtain a resistance of . of an ohm, it is necessary to sensibly satisfy the equation , l/s = / , _l_ expressing the thickness of the voltameter expressed in meters, and _s_ being the section in square millimeters. for example: for l = / , s = , , , say square meters. it will be seen from this example what should be the proportions of apparatus designed for a production on a large scale. the new principles that permit of the construction of such voltameters are as follows: ( ) the substitution of an alkaline for the acid solution, thus affording a possibility of employing iron electrodes; ( ) the introduction of a porous partition between the electrodes, for the purpose of separating the gases. _electrolytic liquid._--commandant renard's experiments were made with per cent, solution of caustic soda and water containing per cent. of acid. these are the proportions that give the maximum of conductivity. experiments made with a voltameter having platinum electrodes separated by an interval of or centimeters showed that for a determinate e.m.f. the alkaline solution allows of the passage of a slighter intenser current than the acidulated water, that is to say, it is less resistant and more advantageous from the standpoint of the consumption of energy. _porous partition._--let us suppose that the two parts of the trough are separated by a partition containing small channels at right angles with its direction. it is these channels alone that must conduct the electricity. their conductivity (inverse of resistance) is proportional to their total section, and inversely proportional to their common length, whatever be their individual section. it is, therefore, advantageous to employ partitions that contain as many openings as possible. the separating effect of these partitions for the gas is wholly due to capillary phenomena. we know, in fact, that water tends to expel gas from a narrow tube with a pressure inversely proportional to the tube's radius. in order to traverse the tube, the gaseous mass will have to exert a counter-pressure greater than this capillary pressure. as long as the pressure of one part and another of the wet wall differs to a degree less than the capillary pressure of the largest channel, the gases disengaged in the two parts of the trough will remain entirely separate. in order that the mixing may not take place through the partition above the level of the liquid (dry partition), the latter will have to be impenetrable in every part that emerges. the study of the partitions should be directed to their separating effect on the gases, and to their electric resistance. in order to study the first of these properties, the porous partition, fixed by a hermetical joint to a glass tube, is immersed in the water (fig. ). an increasing pressure is exerted from the interior until the passage of bubbles is observed. the pressure read at this moment on the manometer indicates (transformed above the electrolytic solution) the changes of level that the bath may undergo. the different porcelains and earths behave, from this point of view, in a very unequal manner. for example, an earthen vessel from the pillivayt establishment supports some decimeters of water, while the porcelain of boulanger, at choisy-le-roi, allows of the passage of the gas only at pressures greater than one atmosphere, which is much more than is necessary. wire gauze, canvas, and asbestos cloth resist a few centimeters of water. it might be feared, however, that the gases, violently projected against these partitions, would not pass, owing to the velocity acquired. upon this point experiment is very reassuring. after filling with water a canvas bag fixed to the extremity of a rubber tube, it is possible to produce in the interior a tumultuous disengagement of gas without any bubbles passing through. [illustration: fig. .--arrangement for the study of capillary reaction in porous vessels.] from an electrical point of view, partitions are of very unequal quality. various partitions having been placed between electrodes spaced three centimeters apart, currents were obtained which indicated that, with the best of porcelains, the rendering of the apparatus is diminished by one-half. asbestos cloth introduces but an insignificant resistance. to this inconvenience of porous vessels is added their fragility, their high price, and the impossibility of obtaining them of the dimensions that large apparatus would call for. the selection of asbestos cloth is therefore clearly indicated; but, as it does not entirely separate the gases, except at a pressure that does not exceed a few centimeters of water, it was always necessary to bring back the variation of the level to these narrow limits by a special arrangement. we cannot, in fact, expect that the entire piping shall be always in such conditions that no difference in pressure can occur. the levels are brought back to equality within the effective limits by interposing between the voltameter and the piping an apparatus called a compensator, which consists of two vessels that communicate in the interior part through a large tube. the gases enter each vessel through a pipe that debouches beneath the level of the water. if a momentary stoppage occurs in one of the conduits, the water changes level in the compensator, but the pressure remains constant at the orifice of the tubes. the compensator is, as may be seen, nothing more than a double mariotte flask. when it is desired to obtain pure gases, there is introduced into the compensator a solution of tartaric acid, which retains the traces of alkalies carried along by the current of gas. the alkaline solution, moreover, destroys the ozone at the moment of its formation. it will be seen that laboratory studies have furnished all the elements of a problem which is now capable of entering the domain of practice. the cheapness of the raw materials permits of constructing apparatus whose dimensions will no longer be limited except by reasons of another nature. the electrodes may be placed in proximity at will, owing to the use of the porous partition. it may be seen, then, that the apparatus will have a considerable useful effect without its being necessary to waste the electric energy beyond measure. _industrial apparatus._--we have shown how the very concise researches of commandant renard have fixed the best conditions for the construction of an industrial voltameter. it remains for us to describe this voltameter itself, and to show the rendering of it. [illustration: fig. .--plant for the industrial electrolysis of water.] the industrial voltameter consists of a large iron cylinder. a battery of such voltameters is shown to the left of fig. , and one of the apparatus, isolated, is represented in fig. . the interior electrode is placed in an asbestos cloth bag, which is closed below and tied at its upper part. it is provided with apertures which permit of the ascent of the gases in the interior of the cylinder. the apparatus is hermetically sealed at the top, the two electrodes being naturally insulated with rubber. above the level of the liquid the interior electrode is continuous and forms a channel for the gas. the hydrogen and oxygen, escaping through the upper orifices, flow to the compensator. the apparatus is provided with an emptying cock or a cock for filling with distilled water, coming from a reservoir situated above the apparatus. [illustration: fig. .--details of an industrial voltameter.] the constants of the voltameter established by commandant renard are as follows: height of external electrode . m. " internal " . " diameter of external " . " " internal " . " the iron plate employed is millimeters in thickness. the electric resistance is about . ohm. the apparatus gives amperes under . volts, and consequently nearly kilowatt. its production in hydrogen is liters per hour. it is clear that, in an industrial exploitation, a dynamo working under volts is never employed. in order to properly utilize the power of the dynamo, several voltameters will be put in series--a dozen, for example, if the generating machine is in proximity to the apparatus, or a larger number if the voltameters are actuated by a dynamo situated at a distance, say in the vicinity of a waterfall. fig. will give an idea of a plant for the electrolysis of water. it remains for us to say a few words as to the net cost of the hydrogen and oxygen gases produced by the process that we have just described. we may estimate the value of a voltameter at a hundred francs. if the apparatus operates without appreciable wear, the amortizement should be calculated at a very low figure, say per cent., which is large. in continuous operation it would produce more than , cubic meters of gas a year, say a little less than one centime per cubic meter. the caustic soda is constantly recuperated and is never destroyed. the sole product that disappears is the distilled water. now one cubic meter of water produces more than , cubic meters of gas. the expense in water, then, does not amount to a centime per cubic meter. the great factor of the expense resides in the electric energy. the cost of surveillance will be minimum and the general expenses _ad libitum_. let us take the case in which the energy has to be borrowed from a steam engine. supposing very small losses in the dynamo and piping, we may count upon a production of one cubic meter of hydrogen and cubic decimeters of oxygen for horse-power taken upon the main shaft, say an expenditure of kilogrammes of coal or of about centimes--a little more in paris, and less in coal districts. if, consequently, we fix the price of the cubic meter of gas at centimes, we shall preserve a sufficient margin. in localities where a natural motive power is at our disposal, this estimate will have to be greatly reduced. we may, therefore, expect to see hydrogen and oxygen take an important place in ordinary usages. from the standpoint alone of preservation of fuel, that is to say, of potential energy upon the earth, this new conquest of electricity is very pleasing. waterfalls furnish utilizable energy in every locality, and, in the future, will perhaps console our great-grandchildren for the unsparing waste that we are making of coal.--_la nature._ * * * * * [continued from supplement, no. , page .] musical instruments: their construction and capabilities. by a.j. hipkins, f.s.a. lecture ii. i will now invite your attention to the wind instruments, which, in handel's time, were chiefly used to double in unison the parts of stringed instruments. their modern independent use dates from haydn; it was extended and perfected by mozart, beethoven, and weber; and the extraordinary changes and improvements which have been effected during the present century have given wind instruments an importance that is hardly exceeded by that of the stringed, in the formation of the modern orchestra. the military band, as it now exists, is a creation of the present century. the so-called wood wind instruments are the flute, oboe, bassoon, and clarinet. it is as well to say at once that their particular qualities of tone do not absolutely depend upon the materials of which they are made. the form is the most important factor in determining the distinction of tone quality, so long as the sides of the tube are equally elastic, as has been submitted to proof by instruments made of various materials, including paper. i consider this has been sufficiently demonstrated by the independent experiments of mr. blaikley, of london, and mr. victor mahillon, of brussels. but we must still allow mr. richard shepherd rockstro's plea, clearly set forth in a recently published treatise on the flute, that the nature and the substance of the tube, by reciprocity of vibration, exercise some influence, although not so great as might have been expected, on the quality of the tone. but i consider this influence is already acknowledged in my reference to equality of elasticity in the sides of the tube. the flute is an instrument of _embouchure_--that is to say, one in which a stream of air is driven from the player's lips against an edge of the blow hole to produce the sound. the oboe and bassoon have double reeds, and the clarinet a single reed, made of a species of cane, as intermediate agents of sound production. there are other flutes than that of _embouchure_--those with flageolet or whistle heads, which, having become obsolete, shall be reserved for later notice. there are no real tenor or bass flutes now, those in use being restricted to the upper part of the scale. the present flute dates from , when theobald boehm, a bavarian flute player, produced the instrument which is known by his name. he entirely remodeled the flute, being impelled to do so by suggestions from the performance of the english flautist, charles nicholson, who had increased the diameter of the lateral holes, and by some improvements that had been attempted in the flute by a captain gordon, of charles the tenth's swiss guard. boehm has been sufficiently vindicated from having unfairly appropriated gordon's ideas. the boehm flute, since , is a cylindrical tube for about three-fourths of its length from the lower end, after which it is continued in a curved conical prolongation to the cork stopper. the finger holes are disposed in a geometrical division, and the mechanism and position of the keys are entirely different from what had been before. the full compass of the boehm flute is chromatic, from middle c to c, two octaves above the treble clef c, a range of three octaves, which is common to all concert flutes, and is not peculiar to the boehm model. of course this compass is partly produced by altering the pressure of blowing. columns of air inclosed in pipes vibrate like strings in sections, but, unlike strings, the vibrations progress in the direction of length, not across the direction of length. in the flute, all notes below d, in the treble clef, are produced by the normal pressure of wind; by an increasing pressure of overblowing the harmonics, d in the treble clef, and a and b above it, are successively attained. the fingerholes and keys, by shortening the tube, fill up the required intervals of the scale. there are higher harmonics still, but flautists generally prefer to do without them when they can get the note required by a lower harmonic. in boehm's flute, his ingenious mechanism allows the production of the eleven chromatic semitones intermediate between the fundamental note of the flute and its first harmonic, by holes so disposed that, in opening them successively, they shorten the column of air in exact proportion. it is, therefore, ideally, an equal temperament instrument and not a d major one, as the conical flute was considered to be. perhaps the most important thing boehm did for the flute was to enunciate the principle that, to insure purity of tone and correct intonation, the holes must be put in their correct theoretical positions; and at least the hole below the one giving he sound must be open, to insure perfect venting. boehm's flute, however, has not remained as he left it. improvements, applied by clinton, pratten, and carte, have introduced certain modifications in the fingering, while retaining the best features of boehm's system. but it seems to me that the reedy quality obtained from the adoption of the cylindrical bore which now prevails does away with the sweet and characteristic tone quality of the old conical german flute, and gives us in its place one that is not sufficiently distinct from that of the clarinet. the flute is the most facile of all orchestral wind instruments; and the device of double tonguing, the quick repetition of notes by taking a staccato t-stop in blowing, is well known. the flute generally goes with the violins in the orchestra, or sustains long notes with the other wood wind instruments, or is used in those conversational passages with other instruments that lend such a charm to orchestral music. the lower notes are not powerful. mr. henry carte has, however, designed an alto flute in a, descending to violin g, with excellent results. there is a flute which transposes a minor third higher than the ordinary flute; but it is not much used in the orchestra, although used in the army, as is also a flute one semitone higher than the concert flute. the piccolo, or octave flute, is more employed in the orchestra, and may double the melody in the highest octave, or accentuate brilliant points of effect in the score. it is very shrill and exciting in the overblown notes, and without great care may give a vulgar character to the music, and for this reason sir arthur sullivan has replaced it in the score of "ivanhoe" by a high g flute. the piccolo is exactly an octave higher than the flute, excepting the two lowest notes of which it is deficient. the old cylindrical ear-piercing fife is an obsolete instrument, being superseded by a small army flute, still, however, called a fife, used with the side drum in the drum and fife band. the transverse or german flute, introduced into the orchestra by lulli, came into general use in the time of handel; before that the recorders, or flute douces, the flute à bec with beak or whistle head, were preferred. these instruments were used in a family, usually of eight members, viz., as many sizes from treble to bass; or in three, treble, alto or tenor, and bass. a fine original set of those now rare instruments, eight in number, was shown in in the music gallery of the royal military exhibition, at chelsea; a loan collection admirably arranged by captain c.b. day. they were obtained from hesse darmstadt, and had their outer case to preserve them exactly like the recorder case represented in the painting by holbein of the ambassadors, or rather, the scholars, recently acquired for the national gallery. the flageolet was the latest form of the treble, beak, or whistle head flute. the whistle head is furnished with a cavity containing air, which, shaped by a narrow groove, strikes against the sharp edge and excites vibration in the conical pipe, on the same principle that an organ pipe is made to sound, or of the action of the player's mouth and lips upon the blowhole of the flute. as it will interest the audience to hear the tone of shakespeare's recorder, mr. henry carte will play an air upon one. the oboe takes the next place in the wood wind band. the principle of sound excitement, that of the double reed, originating in the flattening of the end of an oat or wheat straw, is of great antiquity, but it could only be applied by insertion in tubes of very narrow diameter, so that the column of air should not be wider than the tongue straw or reed acting upon it. the little reed bound round and contracted below the vibrating ends in this primitive form permitted the adjustment of the lower open end in the tube, it might be another longer reed or pipe which inclosed the air column; and thus a conical pipe that gradually narrows to the diameter of the tongue reed must have been early discovered, and was the original type of the pastoral and beautiful oboe of the modern orchestra. like the flute, the oboe has only the soprano register, extending from b flat or natural below middle c to f above the treble clef, two octaves and a fifth, which a little exceeds the flute downward. the foundation of the scale is d major, the same as the flute was before boehm altered it. triebert, a skillful parisian maker, tried to adapt boehm's reform of the flute to the oboe, but so far as the geometrical division of the scale was concerned, he failed, because it altered the characteristic tone quality of the instrument, so desirable for the balance of orchestral coloration. but the fingering has been modified with considerable success, although it is true by a much greater complication of means than the more simple contrivances that preceded it, which are still preferred by the players. the oboe reed has been much altered since the earlier years of this century. it was formerly more like the reed of the shawm, an instrument from which the oboe has been derived; and that of the present bassoon. it is now made narrower, with much advantage in the refinement of the tone. as in the flute, the notes up to c sharp in the treble clef are produced by the normal blowing, and simply shortening the tube by opening the sound holes. beyond that note, increased pressure, or overblowing, assisted by a harmonic "speaker" key, produces the first harmonic, that of the octave, and so on. the lowest notes are rough and the highest shrill; from a to d above the treble clef, the tone quality of the oboe is of a tender charm in melody. although not loud, its tone is penetrating and prominent. its staccato has an agreeable effect. the place of the oboe in the wood wind band between the flute and the clarinet, with the bassoon for a bass, is beyond the possibility of improvement by any change. like the flute, there was a complete family of oboes in the sixteenth and early in the seventeenth century; the little schalmey, the discant schalmey, from which the present oboe is derived; the alto, tenor, pommer, and bass pommers, and the double quint or contrabass pommer. in all these old finger hole instruments the scale begins with the first hole, a note in the bagpipe with which the drones agree, and not the entire tube. from the bass and double quint pommers came ultimately the bassoon and contra-bassoon, and from the alto pommer, an obsolete instrument for which bach wrote, called the oboe di caccia, or hunting oboe, an appellation unexplained, unless it had originally a horn-like tone, and was, as it has been suggested to me by mr. blaikley, used by those who could not make a real hunting horn sound. it was bent to a knee shape to facilitate performance. it was not exactly the cor anglais or english horn, a modern instrument of the same pitch which is bent like it, and of similar compass, a fifth below the usual oboe. the tenoroon, with which the oboe di caccia has been compared, was a high bassoon really on octave and a fifth below. it has been sometimes overlooked that there are two octaves in pitch between the oboe and bassoon, which has led to some confusion in recognizing these instruments. there was an intermediate instrument a third lower than the oboe, used by bach, called the oboe d'amore, which was probably used with the cornemuse or bagpipe, and another, a third higher than the oboe, called musette (not the small bagpipe of that name). the cor anglais is in present use. it is a melancholy, even mournful instrument, its sole use in the orchestra being very suitable for situations on the stage, the effect of which it helps by depressing the mind to sadness. those who have heard wagner's "tristan und isolde" will remember, when the faithful kurwenal sweeps the horizon, and sees no help coming on the sea for the dying tristan, how pathetically the reed pipe of a careless peasant near, played in the orchestra on a cor anglais, colors the painful situation. the bassoon is the legitimate bass to the oboe and to the wood wind in general. it was evolved in the sixteenth century from the pommers and bombards: the tenors and basses of the shawm or oboe family. with the older instruments, the reeds were not taken hold of immediately by the lips, but were held in a kind of cup, called _pirouette_, which only allowed a very small part of the reed to project. in the oboe and bassoon the player has the full control of the reed with the lips, which is of great importance, both in expression and intonation. the bassoon economizes length, by being turned back upon itself, and, from its appearance, obtains in italy and germany the satirical appellation of "fagotto" or "fagott." it is made of wood, and has not, owing to many difficulties as yet unsurmounted, undergone those changes of construction that have partly transformed other wood wind instruments. from this reason--and perhaps the necessity of a bassoon player becoming intimately familiar with his instrument--bassoons by some of the older makers--notably, savory--are still sought after, in preference to more modern ones. the instrument, although with extraordinary advantages in tone, character, and adaptability, that render it valuable to the composer, is yet complicated and capricious for the performer; but its very imperfections remove it from the mechanical tendencies of the age, often damaging to art; and, as the player has to rely very much upon his ear for correct intonation, he gets, in reality, near to the manipulation of the stringed instruments. the bassoons play readily with the violoncellos, their united tone being often advantageous for effect. when not so used, it falls back into its natural relationship with the wood wind division of the orchestra. the compass of the bassoon is from b flat, an octave below that in the bass clef, to b flat in the treble clef, a range of three octaves, produced by normal pressure, as far as the bass clef f. the f below the bass clef is the true lowest note, the other seven semitones descending to the b flat being obtained by holes and keys in the long joint and bell. these extra notes are not overblown. the fundamental notes are extended as in the oboes and flutes by overflowing to another octave, and afterward to the twelfth. in modern instruments yet higher notes, by the contrivance of small harmonic holes and cross fingerings, can be secured. long notes, scales, arpeggios, are all practicable on this serviceable instrument, and in full harmony with clarinets, or oboes and horns, it forms part of a rich and beautiful combination. there is a very telling quality in the upper notes of the bassoon of which composers have made use. structurally, a bassoon consists of several pieces, the wing, butt, long joints, and bell, and when fitted together, they form a hollow cone of about eight feet long, the air column tapering in diameter from three-sixteenths of an inch at the reed to one and three-quarter inches at the bell end. the bending back at the butt joint is pierced in one piece of wood, and the prolongation of the double tube is usually stopped by a flattened oval cork, but in some modern bassoons this is replaced by a properly curved tube. the height is thus reduced to a little over four feet, and the holes, assisted by the artifice of piercing them obliquely, are brought within reach of the fingers. the crook, in the end of which the reed is inserted, is about twelve inches long, and is adjusted to the shorter branch. the contra-bassoon is an octave lower than the bassoon, which implies that it should go down to the double b flat, two octaves below that in the bass clef, but it is customary to do without the lowest as well as the highest notes of this instrument. it is rarely used, but should not be dispensed with. messrs. mahillon, of brussels, produce a reed contra-bass of metal, intended to replace the contra-bassoon of wood, but probably more with the view of completing the military band than for orchestral use. it is a conical brass tube of large proportions, with seventeen lateral holes of wide diameter and in geometrical relation, so that for each sound one key only is required. the compass of this contra-bass lies between d in the double bass octave and the lower f of the treble clef. the sarrusophones of french invention are a complete family, made in brass and with conical tubes pierced according to geometric relation, so that the sarrusophone is more equal than the oboe it copies and is intended, at least for military music, to replace. being on a larger scale, the sarrusophones are louder than the corresponding instruments of the oboe family. there are six sarrusophones, from the sopranino in e flat to the contra-bass in b flat; and to replace the contra-bassoon in the orchestra there is a lower contrabass sarrusophone made in c, the compass of which is from the double bass octave b flat to the higher g in the bass clef. before leaving the double reed wind instruments, a few words should be said of a family of instruments in the sixteenth century as important as the schalmeys, pommers, and bombards, but long since extinct. this was the cromorne, a wooden instrument with cylindrical column of air; the name is considered to remain in the cremona stop of the organ. the lower end is turned up like a shepherd's crook reversed, from whence the french name "tournebout." cromorne is the german "krummhorn;" there is no english equivalent known. the tone, as in all the reed instruments of the period, was strong and often bleating. the double reed was inclosed in a _pirouette_, or cup, and the keys of the tenor or bass, just the same as with similar flutes and bombards, were hidden by a barrel-shaped cover, pierced with small openings, apparently intended to modify the too searching tone as well as to protect the touch pieces which moved the keys. the compass was limited to fundamental notes, and from the cylindrical tube and reed was an octave lower in pitch than the length would show. in all these instruments provision was made in the holes and keys for transposition of the hands according to the player's habit of placing the right or left hand above the other. the unused hole was stopped with wax. there is a fine and complete set of four cromornes in the museum of the conservatoire at brussels. we must also place among double-reed instruments the various bagpipes, cornemuses, and musettes, which are shawm or oboe instruments with reservoirs of air, and furnished with drones inclosing single reeds. i shall have more to say about the drone in the third lecture. in restricting our attention to the highland bagpipe, with which we are more or less familiar, it is surprising to find the peculiar scale of the chaunter, or finger pipe, in an old arabic scale, still prevailing in syria and egypt. dr. a.j. ellis' lecture on "the musical scales of various nations," read before the society of arts, and printed in the _journal_ of the society, march , , no. , vol. xxxiii., and in an appendix, october , , in the same volume, should be consulted by any one who wishes to know more about this curious similarity. we have now arrived at the clarinet. although embodying a very ancient principle--the "squeaker" reed which our little children still make, and continued in the egyptian arghool--the clarinet is the most recent member of the wood wind band. the reed initiating the tone by the player's breath is a broad, single, striking or beating reed, so called because the vibrating tongue touches the edges of the body of the cutting or framing. a cylindrical pipe, as that of the clarinet, drops, approximately, an octave in pitch when the column of air it contains is set up in vibration by such a reed, because the reed virtually closes the pipe at the end where it is inserted, and like a stopped organ pipe sets up a node of maximum condensation or rarefaction at that end. this peculiarity interferes with the resonance of the even-numbered partials of the harmonic scale, and permits only the odd-numbered partials, , , , and so on, to sound. the first harmonic, as we find in the clarinet, is therefore the third partial, or twelfth of the fundamental note, and not the octave, as in the oboe and flute. in the oboe the shifting of the nodes in a conical tube open at its base, and narrowing to its apex, permits the resonance of the complete series of the harmonic scale, , , , , , and upward. the flute has likewise the complete series, because through the blowhole it is a pipe open at both ends. but while stating the law which governs the pitch and harmonic scale of the clarinet, affirmed equally by observation and demonstration, we are left at present with only the former when regarding two very slender, almost cylindrical reed pipes, discovered in by mr. flinders petrie while excavating at fayoum the tomb of an egyptian lady named maket. mr. petrie dates these pipes about b.c., and they were the principal subject of mr. southgate's recent lectures upon the egyptian scale. now mr. j. finn, who made these ancient pipes sound at these lectures with an arghool reed of straw, was able upon the pipe which had, by finger holes, a tetrachord, to repeat that tetrachord a fifth higher by increased pressure of blowing, and thus form an octave scale, comprising eight notes. "against the laws of nature," says a friend of mine, for the pipe having dropped more than an octave through the reed, was at its fundamental pitch, and should have overblown a twelfth. but mr. finn allows me to say with reference to those reeds, perhaps the oldest sounding musical instruments known to exist, that his experiments with straw reeds seem to indicate low, medium, and high octave registers. the first and last difficult to obtain with reeds as made by us. he seeks the fundamental tones of the maket pipes in the first or low register, an octave below the normal pitch. by this the fifths revert to twelfths. i offer no opinion, but will leave this curious phenomenon to the consideration of my friends, mr. blaikley, mr. victor mahillon, and mr. hermann smith, acousticians intimate with wind instruments. the clarinet was invented about a.d. , by christopher denner, of nuremberg. by his invention, an older and smaller instrument, the chalumeau, of eleven notes, without producible harmonics, was, by an artifice of raising a key to give access to the air column at a certain point, endowed with a harmonic series of eleven notes a twelfth higher. the chalumeau being a cylindrical pipe, the upper partials could only be in an odd series, and when denner made them speak, they were consequently not an octave, but a twelfth above the fundamental notes. thus, an instrument which ranged, with the help of eight finger holes and two keys, from f in the bass clef to b flat in the treble had an addition given to it at once of a second register from c in the treble clef to e flat above it. the scale of the original instrument is still called chalumeau by the clarinet player; about the middle of the last century it was extended down to e. the second register of notes, which by this lengthening of pipe started from b natural, received the name of clarinet, or clarionet, from the clarino or clarion, the high solo trumpet of the time it was expected that this bright harmonic series would replace. this name of clarinet, or clarionet, became accepted for the entire instrument, including the chalumeau register. it is the communication between the external air and the upper part of the air column in the instrument which, initiating a ventral segment or loop of vibration, forces the air column to divide for the next possible partial, the twelfth, that denner has the merit of having made practicable. at the same time the manipulation of it presents a difficulty in learning the instrument. it is in the nature of things that there should be a difference of tone quality between the lower and upper registers thus obtained; and that the highest fundamental notes, g sharp, a and b flat, should be colorless compared with the first notes of the overblown series. this is a difficulty the player has to contend with, as well as the complexity of fingering, due to there being no less than eighteen sound holes. much has been done to graft boehm's system of fingering upon the clarinet, but the thirteen key system, invented early in this century by iwan muller, is still most employed. the increased complication of mechanism is against a change, and there is even a stronger reason, which i cannot do better than translate, in the appropriate words of m. lavoix fils, the author of a well-known and admirable work upon instrumentation: "many things have still to be done, but inventors must not lose the point in view, that no tone quality is more necessary to the composer than that of the clarinet in its full extent; that it is very necessary especially to avoid melting together the two registers of chalumeau and clarinet, so distinct from each other. if absolute justness for these instruments is to be acquired at the price of those inestimable qualities, it would be better a hundred times to leave it to virtuosi, thanks to their ability, to palliate the defects of their instrument, rather than sacrifice one of the most beautiful and intensely colored voices of our orchestra." there are several clarinets of various pitches, and formerly more than are used now, owing to the difficulty of playing except in handy keys. in the modern orchestra the a and b flat clarinets are the most used; in the military band, b flat and e flat. the c clarinet is not much used now. all differ in tone and quality; the a one is softer than the b flat; the c is shrill. the b flat is the virtuoso instrument. in military bands the clarinet takes the place which would be that of the violin in the orchestra, but the tone of it is always characteristically different. although introduced in the time of handel and bach those composers made no use of it. with mozart it first became a leading orchestral instrument. the basset horn, which has become the sensuously beautiful alto clarinet in e flat, is related to the clarinet in the same way that the cor anglais is to the oboe. basset is equivalent to baryton (there is a basset flute figured in prætorius), and this instrument appears to have been invented by one horn, living at passau, in bavaria, about . his name given to the instrument has been mistranslated into italian as corno di bassetto. there is a bass clarinet employed with effect by meyerbeer in the "huguenots," but the characteristic clarinet tone is less noticeable; it is, however, largely used in military bands. the basset horn had the deep compass of the bass clarinet which separates it from the present alto clarinet, although it was more like the alto in caliber. the alto clarinet is also used in military bands; and probably what the basset horn would have been written for is divided between the present bass and alto clarinets. preceding the invention of the sarrusophone, by which a perfected oboe was contrived in a brass instrument, a modified brass instrument, the saxophone, bearing a similar relation to the clarinet, was invented in by sax, whose name will occur again and again in connection with important inventions in military band instruments. the saxophone is played like the clarinet with the intervention of a beating reed, but is not cylindrical; it has a conical tube like the oboe. the different shape of the column of air changes the first available harmonic obtained by overblowing to the octave instead of the twelfth; and also in consequence of the greater strength of the even harmonics, distinctly changing the tone quality. the sarrusophone may fairly be regarded as an oboe or bassoon; but the saxophone is not so closely related to the clarinet. there are four sizes of saxophone now made between high soprano and bass. starting from the fourth fundamental note, each key can be employed in the next higher octave, by the help of other two keys, which, being opened successively, set up a vibrating loop. the saxophones, although difficult to play, fill an important place in the military music of france and belgium, and have been employed with advantage in the french orchestra. the fingering of all saxophones is that attributed to boehm. the cup shaped mouthpiece must now take the place of the reed in our attention. here the lips fit against a hollow cup shaped reservoir, and, acting as vibrating membranes, may be compared with the vocal chords of the larynx. they have been described as acting as true reeds. each instrument in which such a mouthpiece is employed requires a slightly different form of it. the french horn is the most important brass instrument in modern music. it consists of a body of conical shape about seven feet long, without the crooks, ending in a large bell, which spreads out to a diameter of fifteen inches. the crooks are fitted between the body and the mouthpiece; they are a series of smaller interchangeable tubings, which extend in length as they descend in pitch, and set the instrument in different keys. the mouthpiece is a funnel shaped tube of metal, by preference silver; and, in the horn, is exceptionally not cup shaped, but the reverse: it tapers, as a cone, from three-quarters of an inch diameter to about a minimum of three-sixteenths of an inch, and is a quarter of an inch where the smaller end of the mouthpiece is inserted in the upper opening of the crook. the first horn has a mouthpiece of rather less diameter than the second. the peculiar mouthpiece and narrow tubing have very much to do with the soft voice-like tone quality of the horn. for convenience of holding, the tubing is bent in a spiral form. there is a tuning slide attached to the body, and, of late years, valves have been added to the horn, similar to those applied to the cornet and other wind instruments. they have, to a considerable extent, superseded hand stopping, by which expedient the intonation could be altered a semitone or whole tone, by depression of the natural notes of the instrument. in brass, or other instruments, the natural harmonics depend on the pressure of blowing; and the brass differs entirely from the wood wind, in this respect, that it is rare, or with poor effect, the lowest or fundamental note can be made to sound. stopping the horn is done by extending the open hand some way up the bore; there is half stopping and whole stopping, according to the interval, the half tone or whole tone required. as may be imagined, the stopped notes are weak and dull compared with the open. on the other hand, the tubing introduced for valves not being quite conformable in curve with the instrument, and hampered with indispensable joins, unless in the best form of modern valve, affects the smoothness of tone. no doubt there has been of late years a great improvement in the manufacture of valves. many horns are still made with crooks covering an octave from b flat to b flat, feet inches to feet; but most players now use only the f crook, and trust to the valves, rather than to change the crooks, so that we lose the fullness of sound of those below f. the natural horn was originally in d, but was not always restricted to that key; there have been horns for f, g, high a, and b flat. this may, however, be said for the valve horn, that it does not limit or restrict composers in writing for the open or natural notes, which are always more beautiful in effect. valves were invented and first introduced in prussia about a.d. . at first there were two, but there are now generally three. in this country and france they are worked by pistons, which, when pressed down, give access for the air into channels or supplementary tubings on one side of the main bore, thus lengthening it by a tone for the first valve, a semitone for the second, and a tone and a semitone for the third. when released by the finger, the piston returns by the action of a spring. in large bass and contralto instruments, a fourth piston is added, which lowers the pitch two tones and a semitone. by combining the use of three valves, lower notes are obtained--thus, for a major third, the second is depressed with the third; for a fourth, the first and third; and for the tritone, the first, second, and third. but the intonation becomes imperfect when valves are used together, because the lengths of additional tubing being calculated for the single depressions, when added to each other, they are too short for the deeper notes required. by an ingenious invention of compensating pistons, mr. blaikley, of messrs. boosey's, has practically rectified this error without extra moving parts or altered fingering. in the valve section, each altered note becomes a fundamental for another harmonic scale. in germany a rotary valve, a kind of stop cock, is preferred to the piston. it is said to give greater freedom of execution, the closeness of the shake being its best point, but is more expensive and liable to derangement. the invention of m. adolphe sax, of a single ascending piston in place of a group of descending ones, by which the tube is shortened instead of lengthened, met, for a time, with influential support. it is suitable for both conical and cylindrical instruments, and has six valves, which are always used independently. however, practical difficulties have interfered with its success. with any valve system, however, a difficulty with the french horn is its great variation in length by crooks, inimical to the principle of the valve system, which relies upon an adjustment by aliquot parts. it will, however, be seen that the invention of valves has, by transforming and extending wind instruments, so as to become chromatic, given many advantages to the composer. yet it must, at the same time, be conceded, in spite of the increasing favor shown for valve instruments, that the tone must issue more freely, and with more purity and beauty, from a simple tube than from tubes with joinings and other complications, that interfere with the regularity and smoothness of vibration, and, by mechanical facilities, tend to promote a dull uniformity of tone quality. owing to the changes of pitch by crooks, it is not easy to define the compass of the french horn. between c in the bass clef and g above the treble will represent its serviceable notes. it is better that the first horn should not descend below middle c, or the second rise above the higher e of the treble clef. four are generally used in modern scores. the place of the horn is with the wood wind band. from handel, every composer has written for it, and what is known as the small orchestra of string and wood wind bands combined is completed by this beautiful instrument. the most prominent instruments that add to the splendor of the full orchestra are trumpets and trombones. they are really members of one family, as the name trombone--big trumpet--implies, and blend well together. the trumpet is an instrument of court and state functions, and, as the soprano instrument, comes first. it is what is known as an eight foot instrument in pitch, and gives the different harmonics from the third to the twelfth, and even to the sixteenth. it is made of brass, mixed metal, or silver, and is about five feet seven inches in real length, when intended for the key of f without a slide; but is twice turned back upon itself, the first and third lengths lying contiguous, and the second about two inches from them. the diameter is three-eighths of an inch along the cylindrical length; it then widens out for about fifteen inches, to form the bell. when fitted with a slide for transposition--an invention for the trumpet in the last century--this double tubing, about five inches in length on each side, is connected with the second length. it is worked from the center with the second and third fingers of the right band, and, when pulled back, returns to its original position by a spring. there are five crooks. the mouthpiece is hemispherical and convex, and the exact shape of it is of great importance. it has a rim with slightly rounded surface. the diameter of the mouthpiece varies according to the player and the pitch required. with the first crook, or rather shank, and mouthpiece, the length of the trumpet is increased to six feet, and the instrument is then in the key of f. the second shank transposes it to e, the third to e flat, and the fourth to d. the fifth, and largest--two feet one and a half inches long--extends the instrument to eight feet, and lowers the key to c. the slide is used for transposition by a semitone or a whole tone, thus making new fundamentals, and correcting certain notes of the natural harmonic scale, as the seventh, eleventh, and thirteenth, which do not agree with our musical scale. mr. w. wyatt has recently taken out a patent for a double-slide trumpet, which possesses a complete chromatic scale. in the required length of slide the ear has always to assist. it is clear that the very short shifts of a double slide demand great nicety of manipulation. it is, of course, different with the valve trumpet. the natural trumpets are not limited to one or two keys, but those in f, e, e flat, d, b flat, and even a have been employed; but, usually, the valve trumpets are in f, and the higher b flat, with a growing inclination, but an unfortunate one, to be restricted to the latter, it being easier for cornet players. the tone of the high b flat trumpet cannot, however, compare with the f one, and with it the lowest notes are lost. of course, when there are two or three trumpets, the high b flat one finds a place. however, the valve system applied to the trumpet is not regarded with satisfaction, as it makes the tone dull. for grand heroic effect, valve trumpets cannot replace the natural trumpets with slides, which are now only to be heard in this country. the simple or field trumpet appears to exist now in one representative only, the e flat cavalry trumpet. bach wrote for trumpets up to the twentieth harmonic--but for this the trumpet had to be divided into a principal, which ended at the tenth harmonic--and the clarino in two divisions, the first of which went from the eighth harmonic up to as high as the player could reach, and the second clarino, from the sixth to the twelfth. the use of the clarinet by composers about the middle of the last century seems to have abolished these very high trumpets. so completely had they gone, by the time of mozart, that he had to change handel's trumpet parts, to accommodate them to performers of his own time, and transfer the high notes to the oboes and clarinets. having alluded to the cornet à piston, it may be introduced here, particularly as from being between a trumpet and a bugle, and of four foot tone, it is often made to do duty for the more noble trumpet. but the distinctive feature of this, as of nearly all brass instruments since the invention of valves, tends to a compromise instrument, which owes its origin to the bugle. the cornet à piston is now not very different from the valve bugle in b flat on the one hand and from the small valve trumpet in the same key on the other. it is a hybrid between this high pitch trumpet and the bugle, but compared with the latter it has a much smaller bell. by the use of valves and pistons, with which it was the first to be endowed, the cornet can easily execute passages of consecutive notes that in the natural trumpet can only be got an octave higher. it is a facile instrument, and double tonguing, which is also possible with the horn and trumpet, is one of its popular means for display. it has a harmonic compass from middle c to c above the treble clef, and can go higher, but with difficulty. a few lower notes, however, are easily taken with the valves. we now come to the trombones, grand, sonorous tubes, which, existing in three or four sizes since the sixteenth century, are among the most potent additions on occasion to the full orchestra. their treble can be regarded as the english slide trumpet, but it is not exactly so. there appears to have been as late as bach a soprano trombone, and it is figured by virdung, a.d. , as no larger than the field trumpet. the trumpet is not on so large a caliber, and in the seventeenth century had its own family of two clarinos and three tubas. the old english name of the trombone is sackbut. the old wooden cornet, or german zinke, an obsolete, cupped mouthpiece instrument, the real bass of which, according to family, is the now obsolete serpent, was used in the sixteenth and seventeenth centuries as the treble instrument in combination with alto, tenor, and bass trombones. the leading features of the trumpet are also found, as already inferred, in the trombone; there is the cupped mouthpiece, the cylindrical tubing, and, finally, a gradual increase in diameter to the bell. the slide used for the trumpet appears for four centuries, and probably longer, in the well known construction of the trombone. in this instrument it consists of two cylindrical tubes parallel with each other, upon which two other tubes communicating by a pipe at their lower ends curved in a half circle glide without loss of air. the mouthpiece is fitted to an upper end, and a bell to a lower end of the slide. when the slide is closed, the instrument is at its highest pitch, and as the column of air is lengthened by drawing the slide out, the pitch is lowered. by this contrivance a complete chromatic scale can be obtained, and as the determination of the notes it produces is by ear, we have in it the only wind instrument that can compare in accuracy with stringed instruments. the player holds a cross bar between the two lengths of the instrument, which enables him to lengthen or shorten the slide at pleasure, and in the bass trombone, as the stretch would be too great for the length of a man's arm, a jointed handle is attached to the cross bar. the player has seven positions, each a semitone apart for elongation, and each note has its own system of harmonics, but in practice he only occasionally goes beyond the fifth. the present trombones are the alto in e flat descending to a in the seventh position; the tenor in b flat descending to e; the bass in f descending to b, and a higher bass in g descending to c sharp. wagner, who has made several important innovations in writing for bass brass instruments, requires an octave bass trombone in b flat; an octave lower than the tenor one, in the "nibelungen." the fundamental tones of the trombone are called "pedal" notes. they are difficult to get and less valuable than harmonics because, in all wind instruments, notes produced by overblowing are richer than the fundamental notes in tone quality. valve trombones do not, however, find favor, the defects of intonation being more prominent than in shorter instruments. but playing with wide bore tubas and their kindred is not advantageous to this noble instrument. the serpent has been already mentioned as the bass of the obsolete zinken or wooden cornets, straight or curved, with cupped mouthpiece. it gained its serpentine form from the facility given thereby to the player to cover the six holes with his fingers. in course of time keys were added to it, and when changed into a bassoon shape its name changed to the russian bass horn or basson russe. a parisian instrument maker, halary, in , made this a complete instrument, after the manner of the keyed bugle of halliday, and producing it in brass called it the ophicleide, from two greek words meaning serpent and keys--keyed serpent--although it was more like a keyed bass bugle. the wooden serpent has gone out of use in military bands within recollection, the ophicleide from orchestras only recently. it has been superseded by the development of the valved tubas. the euphonium and bombardon, the basses of the important family of saxhorns, now completely cover the ground of bass wind instrument music. the keyed bugle, invented by joseph halliday, bandmaster of the cavan militia, in , may be regarded as the prototype of all these instruments, excepting that the keys have been entirely replaced by the valve system, an almost contemporary invention by stölzel and blumel, in prussia, in . the valve instruments began to prevail as early as . the sound tube of all bugles, saxhorns, and tubas is conical, with a much wider curve than the horn. the quality of tone produced is a general kind of tone, not possessing the individuality of any of the older instruments. all these valve instruments may be comprehended under the french name of saxhorn. there is a division between them of the higher instruments or bugles, which do not sound the fundamental note, and of the lower, or tubas, which sound it readily. properly military band instruments, the second or bass division, has been taken over to the orchestra; and wagner has made great use of it in his great scores. the soprano cornets, bugles, or flugelhorns and saxhorns are in e flat; the corresponding alto instruments in b flat, which is also the pitch of the ordinary cornet. the tenor, baryton, and bass instruments follow in similar relation; the bass horns are, as i have said, called tubas; and that with four valves, the euphonium. the bombardon, or e flat tuba, has much richer lower notes. for military purposes, this and the contrabass--the helicon--are circular. finally, the contrabass tubas in b flat, and in c, for wagner, have immense depth and potentiality of tone; all these instruments are capable of pianissimo. there are many varieties now of these brass instruments, nearer particulars of which may be found in gevaert, and other eminent musicians' works on instrumentation. one fact i will not pass by, which is that, from the use of brass instruments (which rise in pitch so rapidly under increase of temperature, as mr. blaikley has shown, almost to the coefficient of the sharpening under heat in organ pipes) has come about that rise in pitch which, from to --until repressed by the authority of the late sir michael costa, and, more recently, by the action of the royal military college at kneller hall--is an extraordinary feature in musical history. all previous variations in pitch--and they have comprised as much as a fourth in the extremes--having been due either to transposition, owing to the requirements of the human voice, or to national or provincial measurements. the manufacture of brass instruments is a distinct craft, although some of the processes are similar to those used by silversmiths, coppersmiths, and braziers. i have only time to add a few words about the percussion instruments which the military band permits to connect with the wind. drums are, with the exception of kettle drums, indeterminate instruments, hardly, in themselves, to be regarded as musical, and yet important factors of musical and especially rhythmic effect. the kettle drum is a caldron, usually of brass or copper, covered with a vellum head bound at the edge round an iron ring, which fits the circle formed by the upper part of the metal body. screws working on this ring tune the vellum head, or vibrating membrane as we may call it, by tightening or slackening it, so as to obtain any note of the scale within its compass. the tonic and dominant are generally required, but other notes are, in some compositions, used; even octaves have been employed. the use beethoven made of kettle drums may be regarded among the particular manifestations of his genius. two kettle drums may be considered among the regular constituents of the orchestra, but this number has been extended; in one remarkable instance, that of berlioz in his requiem, to eight pairs. according to mr. victor de pontigny, whose article i am much indebted to (in sir george grove's dictionary) upon the drum, the relative diameters, theoretically, for a pair of kettle drums are in the proportion of to , bass and tenor; practically the diameter of the drums at the french opera is and ¼ inches, and of the crystal palace band, and ¼ inches. in cavalry regiments the drums are slung so as to hang on each side of the drummers horse's neck. the best drum sticks are of whalebone, each terminating in a small wooden button covered with sponge. for the bass drum and side drum i must be content to refer to mr. victor de pontigny's article, and also for the tambourine, but the provencal tambourines i have met with have long, narrow sound bodies, and are strung with a few very coarse strings which the player sounds with a hammer. this instrument is the rhythmic bass and support to the simple galoubet, a cylindrical pipe with two holes in front and one behind, sounded by the same performer. the english pipe and tabor is a similar combination, also with one player, of such a pipe and a small drum-head tambourine. lastly, to conclude percussion instruments, cymbals are round metal plates, consisting of an alloy of copper and tin--say parts to --with sunk hollow centers, from which the greek name. they are not exactly clashed together to elicit their sound, but rubbed across each other in a sliding fashion. like the triangle, a steel rod, bent into the form indicated by the name, but open at one corner so as to make it an elastic rod, free at both ends; the object is to add to the orchestral matter luminous crashes, as it were, and dazzling points of light, when extreme brilliancy is required. in conclusion, i must be allowed to express my obligations to dr. w.h. stone and mr. victor mahillon, to mr. ebenezer prout, mr. richard shepherd rockstro, mr. lavoix fils, and dr. h. riemann, whose writings concerning wind instruments have materially helped me; to messrs. boosey & co., and to messrs. rudall, carte & co., for the loan of the instruments used in the illustrations; and also to mr. d.j. blaikley and mr. henry carte, for valuable personal aid on the present occasion. their kindness in reading through my manuscript--mr. blaikley throughout--and in offering friendly and generous criticisms; also their presence and assistance by trial of the various instruments, i cannot adequately thank them for, or sufficiently extol. (in the course of this lecture, mr. henry carte played upon a concert flute, also a b flat and a g flute, an eight-keyed flute, and a recorder. mr. d.j. blaikley continued the illustrations upon the oboe, bassoon, clarinet, french horn, slide trumpet, valve tenor horn, cornet à piston, b flat tenor slide trombone, b flat euphonium, b flat contrabass tuba, and b flat contrabass double slide trombone.) * * * * * how gas cylinders are made. the supply of compressed gas in metal cylinders has now assumed the proportions of an important industry, more especially since it was found possible, by the brin process, to obtain oxygen direct from the atmosphere. the industry is not exactly a new one, for carbon dioxide and nitrous oxide (the latter for the use of dentists) have been supplied in a compressed state for many years. now, with the creation of the modern amateur photographer, who can make lantern slides, and the more general adoption of the optical lantern for the purposes of demonstration and amusement, there has arisen a demand for the limelight such as was never experienced before, and as the limelight is dependent upon the two gases, hydrogen and oxygen, for its support, these gases are now supplied in large quantities commercially. at first the gas cylinders were made of wrought iron; they were cumbrous and heavy, and the pressure of the inclosed gas was so low that a receptacle to hold only ten feet was a most unwieldy concern. but times have changed, and a cylinder of about the same size, but half the weight, is now made to hold four times the quantity of gas at the enormous initial pressure of , pounds on every square inch. this means the pressure which an ordinary locomotive boiler has to withstand multiplied by twelve. the change is due to improved methods of manufacture and to the employment of mild steel of special quality in lieu of the wrought iron previously employed. the cylinders are now made without joint or seam, and the process of manufacture is most interesting. a short time ago we had an opportunity of watching the various necessary operations involved in making these cylinders at the birmingham works of messrs. taunton, delamard & co., by whose courtesy we were enabled to make notes of the process. [illustration: fig. .] [illustration: fig. .] beginning with the raw material, we were shown a disk of metal like that shown in fig. , and measuring thirty inches in diameter and three-quarters of an inch in thickness. from such a "blank" a cylinder destined to hold feet of compressed gas can be constructed, and the first operation is to heat the "blank" in a furnace, and afterward to stamp it into the cup-like form shown in fig. . to all intents and purposes this represents the end of a finished cylinder, but it is far too bulky to form the end of one of the size indicated; indeed, it in reality contains enough metal to make the entire vessel. by a series of operations it is now heated and drawn out longer and longer, while its thickness diminishes and its diameter grows less. these operations are carried out by means of a number of hydraulic rams, which regularly decrease in size. fig. roughly represents one of these rams with the plunger ready to descend and force its way into the partially formed red hot gas cylinder, c, and further into the well, w. the plunger may be compared to a finger and the cylinder to a glove, while the well may represent a hole into which both are thrust in order to reduce the thickness of the glove. with huge tongs the cylinder, fresh from the furnace, is placed in position, but just before the plunger presses into the red hot cup, one of the workmen empties into the latter a little water, so as to partially cool the bottom and prevent its being thrust out by the powerful plunger. oil is also used plentifully, so that as the plunger works slowly down the red hot mass, it is surrounded by smoky flames. it presently forces the cylinder into the well, and when the end of the stroke is reached, a stop piece is inserted through an opening in the upper part of the well, so as to arrest the edge of the cylinder while the reverse action of drawing out the plunger is proceeded with. directly the finger is drawn out of the glove--in other words, immediately the plunger is raised out of the cylinder--the latter drops down below with a heavy thud, still in a red hot condition. [illustration: fig .] this operation of hot drawing is repeated again and again in rams of diminishing size until the cylinder assumes the diameter and length required. this hot drawing leaves the surface of the metal marked with longitudinal lines, not unlike the glacier scratches on a rock, albeit they are straighter and more regular. but the next operation not only obliterates these markings, and gives the metal a smooth surface like that of polished silver, but it also confers upon the material a homogeneity which it did not before possess, and without which it would never bear the pressure which it is destined to withstand when finished. this operation consists in a final application of the hydraulic ram while the metal remains perfectly cold, instead of red hot, as in the previous cases. as the result of these various hydraulic operations, we have a perfectly formed cylinder closed at one end, and we now follow it into another department of the works, when its open end is once more brought in a furnace to a red heat. the object of this is to make the metal soft while the shoulder and neck of the vessel are formed. to accomplish this, the heated open end of the cylinder is laid horizontally upon a kind of semicircular cradle, and is held there by tongs handled by two men. another workman places over the open end a die of the form shown in fig. , and while the cylinder is slowly turned round in its cradle, two sledge hammers are brought down with frequent blows upon the die, closing in the end of the cylinder, but leaving a central hole as shown in fig. . further operations reduce the opening still more until it is closed altogether, and a projection is formed as shown at fig. . this projection is now bored through, and the cylinder is ready for testing. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] the cylinder is submitted to a water test, the liquid being forced in until the gauge shows a pressure of two tons to the square inch. cylinders have been known to give way under this ordeal, but without any dangerous consequences. the metal simply rips up, making a report at the moment of fracture as loud as a gun. the wonderful strength of the metal employed may be gauged by the circumstance that the walls of the cylinder designed to hold feet of gas are only five-sixteenths of an inch in thickness. during the manufacture of the cylinder, as we have already indicated, much oil is used, and, so far as steel can be saturated with that fluid--in the popular sense--the metal is in that state. it is essential that this oil should be completely got rid of, and this is carefully done before the cylinder is charged with gas. previous to such charging, the vessel has to be fitted with its valve. of these valves there are three kinds, known respectively as the brin, the birmingham, and the manchester. each has its admirers, but we cannot here discuss their individual merits. the charging of the cylinder is brought about by a powerful pump having three cylinders so arranged that the compressed contents of the first cylinder are still further compressed in the second, and still more highly in the third. the filling of a ft. cylinder occupies about half an hour.--_photographic news_. * * * * * historical development of the horseshoe. by district veterinarian zippelius, of wurtzburg. _translated by s.e. weber, v.s.[ ]_ [footnote : from _theirarztliche mittheilungen_, organ des vereins badischer theirarzte, karlsruhe, no. iv., april, .--_veterinary archives._] kind, gentle steed, nobly standing, four shoes will i put on your feet, firm and good, that you'll be fleet, that is donar's hammer saying. to the woods and homeward go, always on the straight road thro', far from what is bad, still fleeing, that is donar's hammer saying. should wounds and pain become distressing, blood to blood shall flow, bone to bone shall grow, that is donar's hammer saying. carry the rider, true little steed, onward to all good luck bringing; carry him thence and back with speed, that is donar's hammer saying. --_old meresburger song_. the horse appeared comparatively late in the group of domestic animals. in searching the monuments of the ancients, which have furnished the foundation for our present culture, that is, of the littoral inhabitants of the mediterranean, and of the people of mesopotamia, we find in egypt the first traces of the horse. but even here it appears late, on the monuments of the first ruling patricians of human origin.[ ] especially during the period of memphis (i-x dynasty), then under the rules of thebes (xi-xvi dynasty), there is no trace of the horse. [footnote : until the time menes, with whom historical times begin, ruled in egypt among visionary heroes or mythological gods.] it is first in the transition period, from the late rule of thebes (xvii-xx dynasty) to the so-called period of sut (xxi-xxx dynasty) that there appears, in the wall pictures of the pharaohs' tombs, representations of the horse. the oldest, now known, picture of the horse is found on the walls of the tombs of seti i. ( - b.c.) under whose reign the israelite wandered from egypt. the horses of the mortuary pictures are very well drawn, and have an unmistakable oriental type. there has therefore undoubtedly existed in egypt high culture, for over , years, without representation of the horse, which was the next animal domesticated after the cat. from this time on we find the horse frequently represented both by the vainglorious despots of mesopotamia and on the so-called etruscan vases, which appeared after the influence of greek art, when, on almost every urn, horses in lively action and in various forms of bodily development, almost always of an oriental type, are to be recognized. but neither here, nor in homer, nor in the many later representations of the horse on the roman triumphal arches, etc., are to be found horses whose hoofs have any trace of protection. records, which describe to us the misfortunes of armies, whose horses had run their feet sore, we find on the contrary at a very early time, as in diodorus, regarding the cavalry of alexander the great, in xenophon, regarding the retreat of the ten thousand, in polybius, regarding the cavalry of hannibal in etruria, etc. it is also known that the cavalry of the linguist king of pontus, mithridates the great, at times and specially at the siege of cyzicus were delayed, in order to let the hoofs of the horses grow. on the contrary it seems strange that of the huns alone, whose horsemen swept over whole continents from the asiatic highlands like a thunderstorm, such trouble had not become known either through the numerous authors of the eastern and western roman empire or from gallia. horseshoeing, very likely, was invented by different nations at about the same period during the migration of the nations, and the various kinds of new inventions were brought together in germany only, after each had acquired a national stamp according to climate and usefulness. in this way come from the south the thin, plate-like horseshoes, with staved rim, covering the whole hoof; from the mongolian tribes of middle asia the "stolleneisen" (calk shoe); while to our northern ancestors, and indeed the normans, must be ascribed with great probability the invention of the "griffeneisen" (gripe shoe), especially for the protection of the toes. all varieties of the horseshoe of southern europe are easily distinguished from the roman so-called "kureisen" (cure shoe), of which several have been unearthed at various excavations and are preserved at the romo-germanic museum in mentz (mainz), germany. the shoes, figs. and , each represent thin iron plates, covering the whole hoof, which in some cases have an opening in the middle, of several centimeters in diameter. [illustration: fig. .] these plates, apparently set forth to suit oriental and occidental body conformation, are either directly provided with loops or have around the outer margin a brim several centimeters high, in which rings are fastened. through the loops or rings small ropes were drawn, and in this way the shoe was fastened to the crown of the hoof and to the pastern. sufficient securing of the toe was wanting in all these shoes, and, on account of this, the movement of the animal with the same must have been very clumsy, and we can see from this that the ropes must have made the crown of the hoof and pastern sore in a short time. one of these shoes[ ] evidently was the object of improvement, to prevent the animal from slipping as well as from friction, and we therefore find on it three iron cubes ½ centimeters high, which were fastened corresponding to our toes and calks of to-day, and offer a very early ready proof, from our climatic and mountainous conditions, which later occur, principally in southern germany, that this style of horseshoeing was not caused by error, but by a well founded local and national interest or want. [footnote : not illustrated.] [illustration: fig. .] aside from the so-called "kureisen" (cure shoe) for diseased hoofs, we find very little from the romans on horseshoeing or hoof protection, and therefore we must observe special precautions with all their literature on the subject. it is because of this that i excuse prof. sittl's communication in the preface of winckelmann's "geschichte der kunst in alterthum" (history of ancient art), which contains a notice that fabretti, in some raised work in plazzo matti, of a representation of a hunt by the emperor gallienus (bartoli admirand ant. tab. ), showed that at that time horseshoes fastened by nails, the same as to-day, were used (fabretti de column. traj. c. pag. ; conf. montlanc. antiq. explic. t. , pag. ). this statement proves itself erroneous, because he was not aware that the foot of the horse was repaired by an inexperienced sculptor. how then did out of this roman cure shoe develop the horseshoeing of southern europe? it was to be expected, with the roman horseshoe, that the mode of fastening became unsatisfactory and necessitated a remedy or change. an attempt of this kind has been preserved in the so-called "asiatischen koppeneisensole" (asiatic cap-iron-sole) (fig. ), which the hon. mr. lydtin at karlsruhe had made according to a model of the circassian horse tribe shaloks, and also according to the reverse of lycian coins (called triguetra). [illustration: fig. .] this horseshoe plate, likely originating in the twelfth century, covers the whole surface of the sole, like the roman shoes, with the exception of the wall region, which contains a rim centimeter high, and above this rises at one side toward the heel three beak-like projections, about centimeters high and centimeter wide at the base, being pointed above and turned down, which were fastened in the wall of the hoof, in the form of a hook. this mode of fastening evidently was also insufficient, and so the fastening of the shoe by nails was adopted. these iron plates used for shoes were too thin to allow nails with sunken heads to be used, so only nails with blades and cubical shaped heads were applicable. these nail heads, to in number, which left the toe and the back part of the heel free, served at the same time to secure the horse from slipping, which the smooth plates, covering the whole hoof surface, without doubt facilitated. [illustration: fig. .] shoes of this kind, after the old roman style, with a very strong rim bent upward, likely proved very comfortable for the purpose of protection, in the sierras of the pyrenean peninsula, where they seem to have been in use for a long time; for in the twelfth century we find in spain the whole form of the roman shoe, only fastened by nails (figs. and ). at first the shoe seems to have been cut off at the heel end, but as apparently after being on for some time, bruises were noticed, the shoe was made longer at the heel, and this part was turned up so as to prevent them from becoming loose too soon, as both the spanish horseshoes of this period show, and the acquisition was even later transferred to england (fig. ). [illustration: fig. .] the shoe containing a groove (fig. ), which we shall see later, made its appearance in germany in the fifteenth century. from this time, according to our present knowledge, ceases the period of the roman horseshoe. its influence, however, lasted a great deal longer, and has even remained until our present day. [illustration: fig. .] its successor became partly the arabo-turkomanic and partly the southwest european horseshoe. for the descendants of the numidian light cavalry, the roman and old spanish horseshoe was evidently too heavy for their sandy, roadless deserts, so they made it thinner and omitted the bent-up rim, because it prevented the quick movement of the horse. for the protection of the nail heads the outer margin of the shoe was staved, so as to form a small rim on the outer surface of the shoe, thus preventing the nail heads from being worn and the shoe lost too soon. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] a horseshoe of that kind is shown by fig. , which was used in north africa in the twelfth century, and became the model for all forms of horseshoes of the mahometan tribes. even now quite similar shoes (fig. ) are made south and east from the caspian sea, at the amu-darja, in samarkand, etc., which were probably introduced under tamerlane, the conqueror of nearly the whole of asia minor in the fourteenth century. the so-called "sarmatische" (sarmatian) horseshoe (figs. and ), of south russia, shows in its form, at the same time, traces of the last named shoe, however, greatly influenced by the mongolian shoe, the "goldenen horde," which at the turn of the sixteenth to the seventeenth century played havoc at the volga and the aral. the unusual width of the toe, and especially the lightness of the iron, reminds us of the turkomanic horseshoe, whereas, on the contrary, the large bean-shaped holes, as well as the calks, were furnished through mongolian influence. [illustration: fig. .] the sarmatian tribes were principally horsemen, and it is not surprising, therefore, that the coat of arms of the former kingdom of poland in the second and third quadrate shows a silver rider in armor on a silver running horse shod with golden shoes, and that at present about , families in lineages of the polish counts jastrzembiec bolesezy, the so-called "polnische hufeisen adel" (polish horseshoe nobility), at the same time also carried the horseshoe on their coats of arms. the silver horseshoe in a blue field appears here as a symbol of the "herbestpfardes" (autumnal horse), to which, after the christianization of poland, was added the golden cross. the noblemen participating in the murder of the holy stanislaus in had to carry the horseshoe reversed on their escutcheon. [illustration: fig. .] from the african and turkomanic horseshoe, through the turning up of the toes and heels, originated later the turkish, grecian and montenegrin horseshoe of the present as shown by fig. . [illustration: fig. .] by the moorish invasion in spain, the spanish-gothic horseshoeing was also modified, through which the shoe became smooth, staved at the margin, very broad in the toe, and turned up at toe and heel, and at a later period the old open spanish national horseshoe (fig. ) was developed. as we thus see, we can in no way deny the arabian-turkish origin of this shoe. [illustration: fig. .] as france had received her whole culture from the south, and as the crusades especially brought the roman nation in close contact with them for centuries, so it cannot appear strange that the old french horseshoe, a form of which has been preserved by bourgelat and is represented by fig. , still remained in the smooth, turned up in front and behind, like the shoe of the southern climates, with asiatic traces, which hold on the ground, the same as all southern shoeing, by the nail heads. [illustration: fig. .] the transit of the german empire, in order to keep up the historical course, once more brings us back to the middle of the fifth century. at this time attila, the "godegisel" (gods' scourge), left his wooden capitol in the lowlands near the river theis, to go to the roman empire and to the german and gallican provinces, there to spread indescribable misery to the horrors of judgment day. the following is a prayer in those days of horror: "kleiner huf, kleines ross, krummer sabel, spitz geschoss-- blitzesschnell und sattlefest: schrim uns herr von hunnenpest." we are at present reminded of those times of fright, when during the clearing and tilling of the soil, a small roughly made horseshoe is found in southern germany, about as far as the water boundary of the thuringian forest, and occasionally on, but principally around augsburg, and in france as far as the loire. these shoes, covering the margin or wall of the foot, show slight traces of having been beveled on the lower surface, and contain two bent calks very superficially placed. occasionally they are sharpened and turned in two directions. the characteristic wide bean-shaped nail holes are conical on the inside, and are frequently placed so near the outer margin of the shoe that from the pressure the hoofs were likely to split open. the nail heads were shaped like a sleigh runner, and almost entirely sunk into the shoe. it evidently was not bent up at the toe, like the old form of these kinds of shoes. these shoes, according to our conception of to-day, were so carelessly finished that in the scientific circles of historical researches they were, until very recently, looked upon as saddle mountings or something similar, and not as horseshoes. this shoe was for some time, while it was plentifully found in france, regarded as of celtic make; but this is certainly not the case, as it is of hunish and hungarian "nationalitat" (nationality). an exactly scientific proof, it is true, according to our present knowledge, cannot be furnished; however, it will stand well enough until the error is proved. this peculiar kind of horseshoe has been found in south germany and northeast france, as far as the region of orleans, where, as it has been proved, the huns appeared. this, therefore, speaks for their descendants: st, the far extended and yet sharply limited places of finding the shoe; d, the small size corresponds to the historically proved smallness of the hunish horse; d, the hasty and careless make, which does not indicate that it was made by settled workmen; th, the horseshoe (fig. ) bespeaks the hunish workmanship of the present chinese shoe, which, in making of the nail holes, shows to-day related touches of the productions of the mongolian ancestors. [illustration: fig. .] aside from the peculiar shaped nail holes, the characteristic of the hunish shoe consists in the changes of the calks for summer and winter shoeing, as well as in the sinking of the nail heads. the huns, therefore, aside from the indistinctly marked attempts of the romans in this direction, which are the only ones known to me, must be regarded as the inventors not only of the calks, but partly, next to the normans, also of the sharpened winter shoeing, and of the not unimportant invention of sinking the nail heads observed in fig. . the hunish shoeing was therefore an important invention for the germans. after centuries later, wherever horseshoeing was practiced, it was done solely according to hunish methods; whereby the shoe was very possibly made heavier, was more carefully finished and in course of time showed an attempt to bend the toe (fig. a). [illustration: fig. .] [illustration: fig. a.] in the bomberg dom we find an equestrian statue, not unknown in the history of art, which was formerly held to be that of emperor conrad iii. at present however the opinion prevails generally that it represents "stephen i., den heiligen" (stephen i., the saint). stephen i., the first king of hungary, formerly was a heathen, and was named "najk." he reigned from to . his important events were the many victorious wars led against rebellious chieftains of his country, and he was canonized in . his equestrian monument in bomberg dom was, in consequence, hardly made before the year . notwithstanding that the huns had been defeated years before on the plains of catalania, the horse of the above mentioned monument carries, as i have convinced myself personally, hunish horseshoes, modified, however, by blade-shaped calks just then coming into use. this is proof that, at least in hungary, the hunish method of shoeing was preserved an extraordinary long time. by this it has not become improbable that at least the many shoes of this kind which were found on the lechfield come, not directly from the huns, but from their successors, the hungarians, whose invasions took place in the first half of the tenth century. about the same time of the hungarian invasions, the normans began to disturb the southwestern part of europe with their viking expeditions. their sea kings seem to have been equestrians at very early times, and to have had their horses shod, although perhaps only in winter; at least the excavation of the viking ship in disclosed the remains of a horse which was shod. the shoeing consisted only of a toe protection--"brodder" (bruder, brother)--provided with a small sharp calk, and fastened by two nails. when later, in the year , the norwegian king sigard yorsalafar, during his journey to jerusalem, entered constantinople, his horse is said to have carried only the small toe-protecting shoes. the art of horseshoeing, immediately after the migration of the nations, came near our improvement of the same to-day; especially near the reputed discoveries met with, which consist simply of iron protection for the margin of the hoof, fastened by nails. the heads were sunk into the shoe so as to increase its firmness. special consideration was given to local and climatic conditions through the introduction of toes and heels. the mechanism of the hoof also found remarkable consideration, inasmuch as they apparently avoided driving nails too close to the heel end of the shoe. notwithstanding this early improvement in the art of horseshoeing, the huns (as stated before) took a prominent part. it appears to have taken a long time after the migration of the nations for shoeing to become general, as is shown by various descriptions of tournaments, pictures of horses, etc. [illustration: fig. .] we will mention in the first place the "percival des wolfram von eschenbach," as well as "christ von troies," where there is a great deal said about horses, horse grooms, and tournaments, but nowhere in those works is any mention made of horseshoeing. likewise is found the horse on the coat of arms of wolfram von eschenbach, in the manessi collection in paris, which was begun in switzerland in the fourteenth century; but, although we find this horse most beautifully finished, it was not shod. [illustration: fig. .] during the time of the crusades, - , however, there appeared suddenly in germany a plate-like horseshoe of southern character (figs. and ), which was occasionally bent upward at the heel end, and was very heavy. the toe was very broad sometimes, and was also bent upward. in this form we have seen the shoes of the balkan and pyrean peninsula. the shoe was remarkably narrow at the heel, and was supplied with calks, which accounts for the highness of the back part of the shoe. frequently we find one calk set diagonally, but the other drawn out wedge shaped, and sharp; so that there existed a great similarity between this iron shank and that used by count einsiedel for winter shoeing. sometimes both shanks were sharpened in this way, or were provided with blade-shaped calks well set forward. the form of nail holes used was very characteristic of that of the huns, but they were decidedly smaller and square, as were seen in the african shoe of the twelfth century. the nail heads were slightly sunk, which was according to southern customs. that this shoe really belongs to the period of the crusades is proved by the numerous horse pictures which have been preserved from that time; of which we will mention the manuscript of heinrich von veldecka ("eneidt")[ ] in the year , which belongs to the most valuable parts of german history of art. [footnote : "wanderungen des aeneas" (travels of aeneas).] this south european hunish horseshoe had remained the standard form during the middle ages and until the thirty years war, at least in south germany. the shoe was continually improved, and reached its highest point of perfection about the time of the "bauern-krieg" (revolution of the peasants), at a time when, under the leadership of the renaissance, the whole art of mechanics, and especially that of blacksmithing, had taken an extraordinarily great stride (figs. and ). [illustration: fig. .] [illustration: fig. .] the shoe (figs. and ) is found in franconia, in all places where, in the sixteenth century, battles had been fought with the rebellious peasants. we may, therefore, be justified in fixing its origin mainly from that period, for which also speaks its high perfection of form. we find here still the bent-up heel and toe (the latter broad and thin) of the south european form. the staved rim of the spanish arabic turkomanic shoe is observed to be undergoing a change to that of a groove. the broad surface of the shoe evidently led to the beveling of the same, so as to lessen sole pressure. the size of the nail holes remains still like that of the huns; but the unsunk southern nail heads yet serve to improve the hold on the ground. the calks were next placed forward, perhaps from an uncultivated sense of beauty, or from the high bending up of the hind part of the shoe, which would necessitate a high and heavy unsightly calk. from this time on horseshoeing in south germany fell back very quickly, and loses all scientific holds of support after the thirty years war. in the mean time toe protection in the form of a calk had spread from the colder north over southern germany; whereas this north german invention did not find favor in england in consequence of her mild oceanic climate. [illustration: fig. ] also, the calks in england, as well as in the southern countries, on the same ground, therefore, with good reason, could at no time be adopted. this did, however, not interfere with the use of the calk in the colder south germany, where after a use of nearly , years it has maintained its local and climatic adaptation. notwithstanding the occasional aping by foreigners, it has remained victorious in its original form, and has been chosen in many countries. the historical development of the horseshoe in general, from about the time of emperor maximilian until the seven years war, furnishes a true picture of the confused condition of things at that period of time, which, to make intelligible, would require a separate and complete treatise. interesting as it is to the scientist to follow up this development and mode of present german horseshoeing, which, aside from the national toe and calk, is the english form and has become influential, and with full right, for a periodical of this kind further, more comprehensive, statement would under all circumstances take up too much room; therefore i must drop the pen, although reluctantly. [illustration: fig. .] * * * * * sheet glass from molten metal. the present practice in making metal sheets is to cast ingots or slabs and then reduce these by repeated rollings and reheating. attempts have been previously made to produce sheets directly from molten metal by pouring the metal: ( ) between two revolving rollers; or ( ) between a revolving wheel and the surface of an inclosing fixed semicircular segment. by these means none but very thin plates could be satisfactorily produced. in this invention by c.m. pielsticker, london, the machinery consists of a large receiving roller of ft. diameter more or less, and of a length equal to that of the plate to be produced. with this are combined small forming rollers arranged in succession part way round the periphery of the large roller, and revolving at the same rate as the large roller. the rollers can be cooled by a current of water circulating through them. the molten metal flows on to the surface of the large roller and is prevented from escaping sideways by flanges with which the large roller is provided. these flanges embrace the small rollers and are of a depth greater than that of the thickest plate which it is proposed to roll. the distance between the large roller and the small rollers can be adjusted according to the desired thickness of the plate. when dealing with metals of high melting point, such as steel, the first small roller is made of refractory material and is heated from inside by the flame of a blow pipe. the rollers are coated with plumbago or other material to prevent adhesion to the molten metal. in the case of metals of high melting point the machine is fed direct from a furnace divided into two compartments by a wall or bridge in which is a stopper which can be operated so as to regulate the flow of metal. when applied to forming sheets of glass, the rollers should be warmed by a blow pipe flame as above described, and the sheet of glass stretched and annealed as it leaves the last roller. * * * * * weldless steel chains. at the royal naval exhibition, london, messrs. william reid & co. are exhibiting their weldless steel chains, which we now illustrate. of the many advantages claimed for steel chains, it may be prominently noted that a very important saving of weight is effected on account of their possessing such a high breaking strain, compared with the ordinary welded iron chains. to illustrate this, it may be stated that a given length of the weldless steel chain is to per cent. less in weight than an equivalent length of iron chain, will stand the same breaking strain as the latter, and indeed, where steel of special quality is used in making the weldless chains, this difference can be increased as much as to per cent. whereas superior iron chains break at a strain at tons per square inch, these weldless steel chains will stand a strain of to tons, with to per cent. elongation. [illustration: figures . through ., _a_, _b_ and _a_ manufacture of weldless chains.] again, there is greater security in their use from the fact that there are no welds, and they give warning of the limit of strain to which they can bear being approached, by elongation, which can be carried to a considerable extent before the chain breaks. moreover, over, in chains made by this process, the links are all exactly alike. though the life of a weldless steel chain is said to be twice that of an ordinary one, the price per length is little more than that of best iron chains. they are made in lengths of from to feet, being compressed from a solid rolled steel bar, the section of which is shaped like a four-pointed star. in the first place holes are pierced at intervals down the length of the bar, thus determining the length of the several links. then the bar is notched between the holes so as to give the external form of the links. the next step is "flattening out," which presses the links into shape on their inner side, but leaves the openings still closed by a plate of metal. they are then stamped out so as to round them up, and the metal inside them is punched out, and the edges "cleaned," or trimmed off. the links are now parted from one another and stamped again, to insure equal thickness in all parts of the chain. the only processes now to be gone through are dressing and finishing. according to the die used, the shape of the links can be varied to suit any required pattern. the lengths of chain thus made are joined by spiral rings made of soft steel, the convolutions being afterward hammered together till they become solid. a ring of this description, ¾ inch diameter, underwent a strain of , lb., that is, tons to the square inch, its elongation being per cent. these chains have passed satisfactorily the tests of the bureau veritas, and both that association and lloyd's have accepted their use on the same conditions and under the same tests as ordinary chains. so much for the general idea of punching steel chains. we will now describe a recent invention by which superior steel chains are produced, the author of which is mr. hippolyte rongier, of birmingham, eng. he says: my invention has for its object the manufacture of weldless stayed chains, whereof each link, together with its cross strut or stay, is made of one piece of metal without any weld or joint; and the invention consists in producing a chain of stayed links from a bar of cruciform section by the consecutive series of punching, twisting and stamping operations hereinafter described, the punching operations being entirely performed on the metal when in the cold state. figs. to show the progressive stages in the manufacture of the chain, and the remaining figures show the series of tools that are employed. the general method of operation of making stayed chains according to my invention is so far similar to the methods heretofore proposed for making unstayed chains from the bar of cruciform section that the links are formed alternately out of the one and the other pair of diametrically opposite webs of the rod, the links, when severed and completed, being already enchained together at the time of their formation. the successive operations differ, however, in many important practical respects from those heretofore proposed, as will appear from the following detailed description of the successive steps in the process illustrated by figs. to . i will distinguish the one pair of diametrically opposite webs of the bar and the notches and mortises punched therein and the links formed therefrom from the other pair by an index figure affixed to the reference letters appertaining thereto. _a a_ are one pair of diametrically opposite webs, and _a' a'_ the other pair of webs of the bar. [illustration: figures _a-_b, _a_, _a-b_, _a-b_ and _a-b_ manufacture of weldless chains] the first operation illustrated in fig. is to punch out of the edge of one of the webs, _a_, a series of shallow notches, _b_, at equal intervals apart, corresponding to the pitch of the links to be formed out of that pair of webs and situated where the spaces will ultimately be formed between the ends of that series of links. the notches are made with beveled ends, and are no deeper than is absolutely necessary (for the purpose of a guide stop in the subsequent operations, as hereinafter described), so as to avoid, as far as possible, weakening the bar transversely. this operation is repeated upon one of the pairs of webs _a'_; but whereas in the first operation of notching the web the "pitch" of the notches is determined by the feed mechanism, in this second operation of notching the notches, _b_, cut in the web, _a_, serve as guides to influence and compensate for any inaccuracy of the feed mechanism, so that the second set of notches, _b'_, shall be intermediate of and rigorously equidistant from the first set of notches, _b_. this compensation is effected by the notches, _b_, fitting on to a beveled stop on the bed of the punching tool by which the notches, _b'_, are cut, the beveled ends of the notches, _b_, causing the bar under the pressure of the punch to adjust itself in the longitudinal direction (if necessary) sufficiently to rectify any inaccuracy of feed. these notches, _b b'_, similarly serve as guides to insure uniformity of spacing in the subsequent operations of punching out the links. the second operation (illustrated in fig. ) is to punch out of the pair of opposite webs, _a a_, pairs of oblong mortises--two pairs, _c c_, and one pair, _d d_. these three pairs of mortises (which might be punched at separate operations, but are preferably punched at one stroke of the press) are situated as close as possible up to the faces of the other pairs of webs, _a' a'_, the pairs of mortises, _c c_, being so spaced as to correspond in position to the eyes of the links to be formed, to which they correspond approximately in form, while the pair, _d_, correspond in position to the notches, _b_, and therefore to the intervals by which the links formed out of the same pair of webs, _a a_, will be separated when completed. this operation is continued along the whole length of the pair of webs, _a_. it will be observed that a considerable thickness of metal is left at _a*_ between the notches, _b_, and the mortises, _d_. this is of primary importance and is one of the essential features of my method of manufacture, inasmuch as by first punching out the mortises, _d_, the subsequent removal of the metal from between the outer ends of the links is greatly facilitated, while by leaving the solid metal, _a*_, the transverse strength of the webs, _a a_, is not materially diminished, so that when the operation of punching the mortises, _c_ and _d_, in the other pair of webs, _a'_, is performed the bar will not be bent and crippled, as would inevitably be the case were the whole of the metal opposite the notches, _b_, which is ultimately to be removed, to be punched out at so early a stage of the manufacture. the operation of punching the pairs of mortises, _c'_ and _d_, having been repeated along the other pair of webs, _a'_, it will be observed that like the notches, _b_, the mortises, _c d_, in the one pair of webs alternate with those, _c' d'_, in the other pair of webs. the third operation (illustrated in fig. ) is to elongate the mortises, _c d_, and bring the mortises, _c c'_, more nearly to the final form. this is performed by punches similar to but larger (in the direction of the length of the rod) than those used in the second operation. the third operation, which is repeated upon both pairs of webs, _a a a' a'_, may be considered as a second stage of the second operation, it being preferable to punch out the mortises in two stages in order to remove sufficient metal without unduly straining the bar. the fourth operation (illustrated in fig. ) consists in roughly shaping the ends of the links externally by punching out the portions, _a*_, of the webs, _a_, between the links lying in the same plane or formed out of the same pair of webs. this operation is repeated on the other pair of webs, _a'_. up to this point a continuous core of metal has been left at the intersection of the two pairs of webs. the fifth operation (illustrated in fig. ) consists in punching out the portions, _e_, of the core at each side of the cross stay of the link, so as to separate the cross stay from the outer ends of the adjacent links. this operation is performed by removing a portion only of the metal of the core which intervenes between the cross stay and the outer ends of the adjacent links enchained with the link under operation--that is to say, portions, _e*_, of the core are temporarily left attached to the outer ends of the links in order to avoid crippling or bending the bar, which might occur were the whole of this metal, which is ultimately to be removed, to be punched out at once, these portions, _e*_, being supported by the bed die in the operation of punching out the spaces, _e_, as hereinafter described. this operation having been repeated upon both pairs of webs, it will be observed that the rod-like form of the chain is now only maintained by the portion of the core at the points, _f_, where the inner side of the eye or bow of one link is united with that of the next one. the severing of these intervening portions of the core and the breaking up of the rod into the constituent links of the chain constitute the sixth operation. the sixth operation (illustrated in fig. ) is performed by torsion, and for this purpose one end of the rod is held fixed while the other is twisted once or twice in opposite directions, until by fatigue of the metal at the points, _f_, the whole of the links are severed almost at the same instant, and a chain of roughly formed stayed links is produced. the seventh operation (illustrated in fig. ) is to remove the superfluous projecting pieces of metal both from the inside and outside of the ends of the links. for this purpose the two ends of each link are operated on at the same time by two pairs of punches corresponding to the outline of the ends of the link. the eighth operation (illustrated in fig. ) is to bring the ends of the links to their finished rounded form. this is performed by stamping both ends of each link at the same time between pairs of shaping dies or swages. the ninth operation (illustrated in fig. ) is to bring the middle portion of each link--that is to say, the side members and the cross stay--to the finished rounded form, which is also performed by means of a pair of dies or swages. the tenth and last operation (illustrated in fig. ) is to contract the link slightly in the lateral direction in order to correct any imperfections at the sides left by the two previous operations and bring the link to a more perfect and stronger form, as shown. this operation has the important result of strengthening the link considerably by contracting or rendering more pointed the arched form of the bow or end of the link, and also by thickening the metal at that part where the wear is greatest, this thickening of the metal at the ends of the link occurring in the direction of the line of strain (as indicated by _x_ in fig. ) and being brought about by the compression or "upsetting" of the metal at the end of the link. it may be preferable to perform this operation immediately after the seventh operation, and i reserve the right to do so. in the case of large cables only the metal is preferably heated for the eighth, ninth, and tenth operations. i will now refer to the figures which illustrate the series of tools whereby the above mentioned operations are performed. fig. _a_ shows a plan (the punch being in section) and fig. _b_ an elevation of the bed die of the tool by which the notches _b_ of the first operation are performed. the feed mechanism is not shown, but might be of any ordinary intermittent kind. _g_ is a groove in the bed, in which lies the lower vertical web of the rod, of cruciform section, the two horizontal webs lying upon the bed with the edge of the web to be notched lying just over the die, in which works the punch, b, of which b' is the cutting edge. the punch is operated in the usual way, its lower end, which does not rise out of the die, acting as a guide. b* is the beveled stop in the groove, _g_, which by fitting in the notches, _b_ or _b'_, corrects inaccuracies of the feed. fig. _a_ is a sectional plan and fig. _b_ an elevation of the tool by which the second operation is performed, the same tool being also used for performing the third operation. (illustrated in fig. _a_.) _h h_ are a pair of bed-dies having a space _h'_ between them to receive the lower web of the bar, and having notches, c c and d d, in their inner ends, forming counterparts of the punches by which the pairs of mortises, _c d_, fig. , are punched in the pair of webs lying upon the bed-dies, _h_. these bed-dies are fitted to slide a little in opposite directions upon a suitable bed plate and are caused by the inclined cams, _i'_, on the guides, _i_, of the press head (which pass through corresponding apertures in the bed-dies, _h_) to approach each other at the moment the punches come down on the work, so as to grip the lower web of the rod and support the pair of webs being operated on close up to the sides of the lower web lying in the space _h'_, while when the punches rise the bed-dies move apart, so that the web is quite free in said space _h'_ and the rod may be easily fed forward for a fresh stroke of the press. b* is the beveled stop in the space, _k'_, as in the tool first described. the bed-dies _h_ have a second set of notches c' d' at their outer ends, similar to but longer than those c d, so that by reversing the bed-dies they will form counterparts for a second set of punches corresponding thereto for performing the third operation--_i.e._, enlarging the mortises, _c d_, as represented in figs. and _a_; or, instead of adapting the dies, _h_, to perform the two operations, separate tools may be used for the second and third operations. fig. _a_ is an elevation and fig. _b_ a sectional plan of the tool for performing the fourth operation--namely, removing the portion _a*_, figs. , _a_, _a_, and _b_. this is done by a pair of punches, a*, corresponding in shape to the ends of the link in the rough and to the aperture shown in the bed-die, _k_, fig. _b_, which has a groove, _k'_, to admit the lower web of and to guide the rod. the beveled stop, b*, used in operating on the pair of webs, a, corresponds to the notches, _b'_; but in operating on the webs, _a'_, the stop must be replaced by one corresponding to the aperture left by the removal of the portion, _a*_. fig. _a_ is an elevation, fig. _b_ a plan, and fig. _c_ a longitudinal vertical section of the tool for performing the fifth operation, the work being shown in section in the latter figure. it consists of a bed-die, _l_, with groove, _m_, to receive the lower web, but terminating at a distance from the die apertures, so as to leave supports, _n_, for the parts, _e*_, of the rod to resist the downward pressure of the punches, e, which remove the portions, _e_, from each side of the cross stay, as shown in figs. _b_ and _c_. the correct position of the work in regard to the punches is insured by these supporting parts, _n_, which terminate the grooves, _m_. fig. _a_ is an elevation of the winch for performing the sixth operation. fig. _a_ is an elevation and fig. _b_ a plan of the tool for performing the seventh operation. p p are the punches for trimming the outside and q q those for trimming the inside of the ends of the links. the links adjacent to the one to be operated on are brought together into the position shown in dotted lines, the bed-die having an aperture in it to admit of this, so that both ends of the link to be trimmed may be operated on together. the tool for performing the eighth operation consists of a pair of swages, the bottom one only being shown in fig. _a_. the swages correspond to the intended rounded sectional form of the ends of the link, which is placed in position between the swages in a similar manner to that described for fig. _b_, so that both ends are rounded or finished off at once. fig. _a_ is a plan of the bottom swage of the tool for performing the ninth operation, the upper swage corresponding thereto at least in so far as the middle part of the link to be operated on is concerned. the tool for performing the tenth operation is represented in elevation and plan in figs. _a_ and _b_. it consists of a pair of bed-dies, r, fitted to slide together and operated by the cams, s, on the guide rods, s, the operation being similar to that of the tool shown in figs. _a_ and _b_, except that there are no punches, and that the link which lies in the cavity of the dies is merely compressed in the lateral direction by the inward motion of the bed-dies. my invention further comprises a modification of the above described process, which has for its object to enable the weldless stayed links to be made as short and particularly as narrow as may be necessary in order to adapt the chain to run over the sheaves of pulley blocks and to suit other purposes for which short-link welded chain has heretofore only been available. [illustration: figures _a-c_, _a_, _a_, - manufacture of weldless chains.] in the manufacture of chains by the aforesaid process of punching there is a practical minimum limit for the dimensions of the punches which cannot be reduced without compromising their efficiency, and consequently the width (and therefore the length) of the link must necessarily bear a certain proportion to the thickness of the web of metal out of which it is formed, since the breadth of the link depends on the length of the cross stay, which is determined by the breadth of the mortises forming the eyes of the link. the present modification enables these dimensions to be reduced without reducing the dimensions, and consequently the efficiency, of the punches which form the eyes of the link. the modification applies to what i have designated the fifth operation of the above described process; and it consists in punching out the middle of the cross stay (so as to leave only two short stumps jutting inward from the side members of the link), this operation serving to interrupt the continuity of the core, which was the object of the fifth operation. for this purpose i substitute for the pair of punches illustrated in figs. _a_ and _c_ a single punch, which removes that part of the "core" of the cruciform bar which is situated at the middle of the strut. this tool is represented in fig. , and the effect of its operation is shown in fig. . the subsequent operations, herein designated the sixth, seventh, eighth, and ninth operations, are performed as hereinbefore described; but the tenth operation has the effect of closing together the two stumps, _g g_, until they abut together at the middle of the link and together constitute a cross strut or stay, which prevents any further lateral collapse of the link. in the operation of closing up the gap between the stumps, _g g_, the link is brought to the narrow form shown in fig. , the eyes of the links being only just wide enough to receive the end of the adjacent link enchained therewith without gripping it. this operation is performed by a tool similar to that shown in figs. _a_ and _b_, above referred to. * * * * * an english steam fire engine. the steam fire engine of which we give an engraving is one specially built for the indian government by messrs. shand, mason & co., london. it has the distinction of being the first steam fire engine supplied for the province of upper burma, having been purchased primarily for the royal palace, and to serve for the protection of the cantonment of mandalay. the engine is placed vertically in front of the boiler, and consists of a double acting pump with valves which can be taken out for renewal or examination in two or three minutes. the capacity is gallons per minute, and the height of jet ft. as shown in the engraving, the fore part of the machine forms a hose reel and tool box, and can be instantly separated from the engine to allow of the independent use of the latter at a fire. [illustration: improved steam fire engine.] the engine is constructed with wrought iron side frames, fore carriage and wheels, and steel axles, springs, etc. the tool box, coachman's seat, and other parts are of teak. it is provided with messrs. shand, mason & co.'s quick steaming boiler, in which lb. pressure can be raised from cold water in from five to seven minutes, an extra large fire box for burning wood, with fire door at the back, feed pump, and injector, fresh water tank, coal bunker, and other fittings and arrangements for carrying the suction pipe. a pole and sway bars are fitted for two ponies, and wood cross bars to pass over the backs of the animals at the tops of the collars. two men are carried on the machine, a coachman on the box seat and a stoker on the footboard at the rear of the engine. the whole forms a very light and readily transportable fire engine.--_the engineer_. * * * * * the system of military dove cotes in europe.[ ] [footnote : continued from _scientific american_ of july , p. .] _france_.--the history of the aerial postal service and of the carrier pigeons of the siege of paris has been thoroughly written, and is so well known that it is useless to recapitulate it in this place. it will suffice to say that sixty-four balloons crossed the prussian lines during the war of - , carrying with them pigeons, of which were afterward sent back to paris, during a terrible winter, without previous training, and from localities often situated at a distance of over miles. despite the shooting at them by the enemy, returned to their cotes, of them carrying microscopic dispatches. they thus introduced into the capital , official dispatches and a million private ones reduced by photo-micrographic processes. the whole, printed in ordinary characters, would have formed a library of volumes. one of these carriers, which reached paris on the st of january, , a few days previous to the armistice, carried alone nearly , dispatches. the pigeon that brought the news of the victory of coulmiers started from la loupe at ten o'clock in the morning on the tenth of november, and reached paris a few minutes before noon. the account of the villejuif affair was brought from paris to tourcoing (nord) by a white pigeon belonging to mr. descampes. this pigeon is now preserved in a stuffed state in the museum of the city. the carrier pigeon service was not prolonged beyond the st of february, and our winged brothers of arms were sold at a low price at auction by the government, which, once more, showed itself ungrateful to its servants as soon as it no longer had need of their services. after the commune, mr. la perre de roo submitted to the president of the republic a project for the organization of military dove cotes for connecting the french strongholds with each other. mr. thiers treated the project as chimerical, so the execution of it was delayed up to the time at which we saw it applied in foreign countries. in , the government accepted a gift of pigeons from mr. de roo, and had the administration of post offices construct in the garden of acclimatization a model pigeon house, which was finished in , and was capable of accommodating pairs. at present, the majority of our fortresses contain dove cotes, which are perfectly organized and under the direction of the engineer corps of the army. the map in fig. gives the approximate system such as it results from documents consulted in foreign military reviews. according to lieutenant grigot, an officer of the belgian army, who has written a very good book entitled _science colombophile_, a rational organization of the french system requires a central station at paris and three secondary centers at langres, lyons and tours, the latter being established in view of a new invasion. as the distance of paris from the frontier of the north is but miles at the most, the city would have no need of any intermediate station in order to communicate with the various places of the said frontier. langres would serve as a relay between paris and the frontier of the northeast. for the places of the southeast it would require at least two relays, lyons and langres, or dijon. [illustration: fig. .--theoretic map of the french system of military dove cotes.] as paris has ten directions to serve, it should therefore possess ten different dove cotes, of birds each, and this would give a total of , pigeons. according to the same principle, langres, which has five directions to provide for, should have , pigeons. continuing this calculation, we find that it would require , pigeons for the dove cotes as a whole appropriated to the frontiers of the north, northeast, east, and southeast, without taking into account our frontiers of the ocean and the pyrenees. [illustration: fig. .--basket for carrying pigeons.] a law of the d of july, , supplemented by a decree of the th of november, organized the application of carrier pigeons in france. one of the last enumerations shows that there exist in paris , pigeons, , of which are trained, and, in the suburbs, , , of which , are trained. at roubaix, a city of , inhabitants, there are , pigeons. watrelos, a small neighboring city of , inhabitants, has no less than , carrier pigeons belonging to three societies, the oldest of which, that of saint-esprit, was founded in . in entire france, there are about , trained pigeons, and forty-seven departments having pigeon-fancying societies. _germany._--after the war of , prussia, which had observed the services rendered by pigeons during the siege of paris, was the first power to organize military dove cotes. in the autumn of , the minister of war commissioned mr. leutzen, a very competent amateur of cologne, to study the most favorable processes for the recruitment, rearing, and training of carrier pigeons, as well as for the organization of a system of stations upon the western frontier. in , mr. bismarck having received a number of magnificent belgian pigeons as a present, a rearing station was established at the zoological garden of berlin, under the direction of dr. bodinas. in military dove cotes were installed at cologne, metz, strassburg, and berlin. since that time there have been organized, or at least projected, about fifteen new stations upon the frontier of france, upon the maritime coasts of the north, or upon the russian frontier. berlin remains the principal rearing station, with two pigeon houses of pigeons each; but it is at cologne that is centralized the general administration of military dove cotes under mr. leutzen's direction. the other stations are directly dependent upon the commandant of the place, under the control of the inspector of military telegraphy. the wilhelmshaven dove cote, by way of exception, depends upon the admiralty. in each dove cote there is a subofficer of the engineer corps and an experienced civil pigeon fancier, on a monthly salary of ninety marks, assisted by two orderlies. in time of war, this _personnel_ has to be doubled and commanded by an officer. the amount appropriated to the military dove cotes, which in was about , francs, rose in to more than , francs. as a rule, each dove cote should be provided with , pigeons, but this number does not appear to have been yet reached except at thorn, metz, and strassburg. germany has not confined herself to the organization of military dove cotes, but, like other nations, has endeavored to aid and direct pigeon fancying, so as to be able, when necessary, to find ready prepared resources in the civil dove cotes. the generals make it their duty to be present, as far as possible, at the races of private societies, and the emperor awards gold medals for flights of more than miles. on the th of january, , nineteen of these societies, at the head of which must be placed the columbia, of cologne, combined into a federation. at the end of the year the association already included sixty-six societies. on the st of december, , it included seventy-eight, with , carrier pigeons ready for mobilization. the first two articles of the statutes of the federation are as follows: "i. the object of the federation is to unite in one organization all societies of pigeon fanciers in order to improve the service of carrier pigeons, which, in case of war, the country must put to profit. "ii. the federation therefore proposes: (a) to aid the activity of pigeon-fancying societies and to direct the voyages of the societies according to a determined plan; (b) to form itinerent societies and on this occasion to organize expositions and auction sales of pigeons; (c) to maintain relations with the prussian minister of war; (d) to obtain diminutions and favors for transportation; (e) to make efforts for the extermination of vultures; (f) to obtain a legal protection for pigeons; and (g) to publish a special periodical for the instruction of fanciers." _italy._--the first military dove cote in italy was installed in at ancona by the twelfth regiment of artillery. in , a second station was established at bologna. at present there are in the kingdom, besides the central post at rome, some fifteen dove cotes, the principal ones of which are established at naples, gaeta, alexandria, bologna, ancona and placenza. there are at least two on the french frontier at fenestrella and exilles, and two others in sardinia, at cagliari and maddalena. the complete system includes twenty-three; moreover, there are two in operation at massoua and assab. the cost of each cote amounts to about , francs. the pigeons are registered and taken care of by a pigeon breeder (a subofficer) assisted by a soldier. the head of the service is commandant of engineers malagoli, one of the most distinguished of pigeon fanciers. we represent in fig. one of the baskets used in france for carrying the birds to where they are to be set free.--_la nature._ * * * * * the isle of man twin screw steamer tynwald. we place on record the details of the first high speed twin screw steamer built for the service. of this vessel, named the tynwald, we give a profile and an engraving of stern, showing the method of supporting the brackets for propeller shafting. [illustration: twin screws--rear view] the tynwald is feet long, feet inches beam, and feet inches depth moulded, the gross tonnage being tons. the desire of the owners to put the vessel alternately on two distinct services required special arrangement of the saloons. running between liverpool and the island there was no necessity for sleeping accommodation, as the passage is made in about three hours; and the ship had to be suited to carry immense crowds. but as the owners wished on special occasions to run the vessel from glasgow to manxland it was necessary to so arrange the saloons as to admit of sleeping accommodation being provided on these occasions. on the liverpool run the vessel will carry from to passengers. a spacious promenade is an indispensable desideratum, and the upper or shelter deck has been made flush from stem to stern, the only obstructions in addition to the engine and boiler casings, and the deck and cargo working machinery, being a small deck house aft with special state rooms, ticket and post offices, and the companion way to the saloons below. on the main deck forward is a sheltered promenade for second class passengers, while on the lower deck below are dining saloons, the sofas of which may be improvised for sleeping accommodation. at the extreme after end of the main deck is the first class saloon, with the ladies' room forward on the starboard side, and, there being no alley way forward, the ladies' lavatories are provided on the starboard side of the engine casing. on the port side are the gentlemen's lavatories, and smoking saloon and bar. the dining saloon is aft on the lower deck, with ladies' room forward. in the two saloons and ladies' rooms sofa berths can be arranged to accommodate passengers. the crew and petty officers are accommodated in the forward part of the ship. as the profile shows, the vessel is divided by transverse bulkheads into seven watertight compartments, and there are double bottoms. she has six large boats and several rafts. [illustration: the liverpool and isle of man twin screw steamer tynwald.] the twin screws are revolved by separate triple expansion engines, steam being supplied by two double-ended boilers. each boiler is placed fore and aft, and each has a separate uptake and funnel. there are three stokeholds, and to ventilate them and supply sufficient air for the furnaces there is in each a foot fan driven by an independent engine running at revolutions. these have been supplied by messrs. w.h. allen & co., london. the boilers are of steel and adapted for a working pressure of lb. to the square inch. they are feet in diameter and feet long, and there are eight furnaces in each boiler, sixteen in all, the diameter of each furnace being feet ½ inches. the cylinders of the main engines are in., in., and in. in diameter respectively, with a piston stroke of ft. the high-pressure cylinders are each fitted with a piston valve, and the intermediate and low-pressure cylinders with double-ported slide valves, all of which are worked by the usual double eccentric and link motion valve gear, by which the cut-off can be varied as required. all the shafting is forged of siemens-martin mild steel of the best quality, each of the three separate cranks being built up. the condensers are placed at the outsides of the engine room, and the air, feed, and bilge pumps are between the engines and the condensers and worked by levers from the low-pressure engine crosshead. there are two centrifugal pumps, each worked by a separate engine for circulating water through the condenser, and these are so arranged that they can be connected to the bilges in the event of an accident to the ship. in the engine room there is fitted an auxiliary feed donkey of the duplex type and made by the fairfield company. this pump has all the usual connections, so that it can be used for feeding the boilers from the hot well, for filling the fresh water tanks, for pumping from the bilges, or from the sea as a fire engine. the engines are arranged in the ship with the starting platform between them; and the handles for working the throttle valves, starting valves, reversing gear (brown's combined steam and hydraulic), and drain cocks are brought together at one end of the platform, so that the engineer in charge can readily control both engines. the two sets of engines are bound together by two beams bolted to the framing of each engine. this feature was introduced into the design for steadiness. the method of supporting the propeller shaft brackets is interesting, and we reproduce a photograph that indicates the arrangement adopted. instead of the a frame forming part of the same forging as the stern frame, the fairfield company have built up the supporting arms of steel plates riveted together, as is clearly shown. there is an advantage in cost and with less risk in undiscovered flaws in material. an interesting change has been made in the steam pipes. cases of copper steam pipes bursting when subjected to high pressure have not been infrequent, and mr. a. laing, the engineering director on the fairfield board, with characteristic desire to advance engineering practice, has been devoting much attention to this question lately. he has made very exhaustive tests with lap welded iron steam pipes of all diameters, but principally of in. diameter and / in. thickness of material, made by messrs. a. & j. stuart & clydesdale, limited, and the results have been such as to induce him to introduce these into vessels recently built by the company. it may be stated that the pipes only burst at a hydraulic pressure of , lb. to the square inches. the tynwald was tried on the clyde about a month ago, and on two runs on the mile, the one with and the other against the tide, the mean speed was . knots--the maximum was ½ knots--and the indicated horse power developed was , , the steam pressure being lb., and the vacuum lb. since that time the vessel has made several runs from liverpool and from glasgow to the isle of man, and has maintained a steady seagoing speed of between and knots.--_engineering._ * * * * * the treatment of refractory ores. mr. jas. j. shedlock, with the assistance of mr. t. denny, of australia, has constructed on behalf of the metallurgical syndicate, of gresham house, london, an apparatus on a commercial scale, which, it is said, effects at the smallest expense, and with the best economical results, the entire separation of metals from their ores. in treating ores by this process, the stone is crushed in the usual way, either by rolls or stamps, the crushed ore being conveyed into an apparatus, where each atom is subjected to the action of gases under pressure, whereby the whole of the sulphur and other materials which render the ore refractory are separated. the ore is then conveyed into a vessel containing an absorbing fluid metal, so constructed that every particle of the ore is brought into contact with the metal. for the production of reducing gases, steam and air are passed through highly heated materials, having an affinity for oxygen, and the gases so produced are utilized for raising the ore to a high temperature. by this means the sulphur and other metalloids and base metals are volatilized and eliminated, and the gold in the ore is then in such a condition as to alloy itself or become amalgamated with the fluid metal with which it is brought into close contact. the tailings passing off, worthless, are conveyed to the dump. the apparatus in the background is that in which the steam is generated, and which, in combination with the due proportion of atmospheric air, is first superheated in passing through the hearth or bed on which the fire is supported. the superheated steam and air under pressure are then forced through the fire, which is automatically maintained at a considerable depth, by which means the products of combustion are mainly hydrogen and carbonic oxide. these gases are then conveyed by means of the main and branch pipes to the cylindrical apparatus in the foreground, into which the ore to be acted upon is driven under pressure by means of the gases, which, being ignited, raise the ore to a high temperature. the ore is maintained in a state of violent agitation. each particle being kept separate from its fellows is consequently very rapidly acted upon by the gases. the ore freed from its refractory constituents is then fed into a vessel containing the fluid metal, in which each particle of ore is separated from the others, and being acted upon by the fluid metal is absorbed into it, the tailings or refuse passing off freed from any gold which may have been in the ore. [illustration: apparatus for the treatment of refractory ores.] quantities of refractory ores treated by this process are said to have demonstrated that the whole of the gold in the ore is extracted. the successful outcome of these trials is stated to have resulted in the anglo-french exploration co. acquiring the right to work the process on the various gold fields of south africa. it is anticipated that the process will thus be immediately brought to a test by means of apparatus erected on the gold fields under circumstances and conditions of absolute practical work. as is well known, gold-bearing ores in south africa which are below the water line are, by reason of the presence of sulphur, extremely difficult to deal with, and are consequently of small commercial value. the gold in these ores, it is maintained, will, by the new process, be extracted and saved, and make all the difference between successful and unsuccessful mining in that country. it will have been seen that the peculiar and essential features of the invention consist in subjecting every particle of the ore under treatment to the process in all its stages instead of in bulk, thereby insuring that no portion shall escape being acted upon by the gases and the absorbing metal. this is done automatically and in a very rapid manner. it is stated that this method of treatment is applicable to all ores, the most refractory being readily reducible by its means. the advantages claimed for this process are: simplicity of the apparatus, it being practically automatic; that every particle of the ore is separately acted upon in a rapid and efficient manner; that the apparatus is adaptable to existing milling plants; and that there is an absence of elaborate and expensive plant and of the refinements of electrical or chemical science. these advantages imply that the work can be done so economically as to commend the new process to the favorable consideration of all who are interested in mines or mining property.--_iron._ * * * * * refining silver bullion. a number of years ago the author devised a method for refining silver bullion by sulphuric acid, in which iron was substituted for copper as precipitant of silver, the principal feature being the separation of pure crystals of silver sulphate. a full description of this process may be found in percy's metallurgy, "silver and gold," page . the process has been extensively worked in san francisco and in germany in refining bullion to the amount of more than a hundred million dollars' worth of silver. its more general application has been hampered, however, by the circumstance that the patent had been secured by one firm which limited itself to its utilization in its california works. the patent having expired, the author lately introduced a modification of the process by which the apparatus and manipulations are greatly cheapened and simplified. in the following account is given a short description of the process in its present shape. _preparing the silver sulphate._--the bullion, containing, essentially, silver, copper and gold, is dissolved by boiling with sulphuric acid in cast iron pots. the difference between the new process and the usual practice consists in the use of a much larger quantity of acid. thus, in refining ordinary silver "dore," four parts of acid are used to one part of bullion. of this acid one part is chemically and mechanically consumed in the dissolving process, and the remaining three parts are fully recovered and at once ready for reutilization, as will be described hereafter. in the usual process--understanding thereby, here and in the following, the process practiced at the united states mints, for instance--two parts of acid are employed for one of bullion; all of this is lost, partly through the dissolving and partly in being afterward mixed with water, previous to the precipitation of the silver by copper. economy in acid being therefore imperative, the silver solution finally becomes much concentrated, and it requires high heat and careful management to finish the solution of the bullion. bars containing more than about per cent. of copper cannot be dissolved at all, owing to the separation of copper sulphate insoluble in the small amount of free acid finally remaining. the advantage gained by dissolving bullion with abundance of free acid in the improved process is so evident that it merely requires to be pointed out. for bullion containing per cent. of copper the author employs six parts of acid to one of bullion; for baser metal still more acid, and so on, never losing more than the stochiometrical percentage of acid and recovering the remainder. in this description he, however, confines himself to the treatment of ordinary silver ore with less than per cent. of copper. in the diagram a a represent two refining pots, ft. in diameter and ft. in depth, each capable of dissolving at one operation as much as pounds of bullion. the acid is stored in the cast iron reservoir, b, which is placed on a level sufficiently high to charge into a by gravitation, and is composed of fresh concentrated acid mixed with the somewhat dilute acid regained from a previous operation. after the bullion is fully dissolved all the acid still available is run from b into a a. the temperature and strength are thereby reduced, the fuming ceases, any still undissolved copper sulphate dissolves, and the gold settles. in assuming that the settling of the gold takes place in a itself, the author follows the practice of the united states mints. in private refineries, where refining is carried on continuously, the settling may take place in an intermediate vessel, and a a be at once recharged. owing to the large amount of free acid present, the temperature must fall considerably before the separation of silver sulphate commences, and sufficient time may be allowed for settling if the intermediate vessel be judiciously arranged. [illustration] _separating the silver sulphate._--the clarified solution is siphoned off the gold from a a into c, which is an open cast iron pan, say ft. by ft. and ft. deep. it is supported by means of a flange in another larger pan--not shown in the diagram--into which water may be admitted for cooling. steam is blown into the acid solution, still very hot, as soon as c is filled. the steam is introduced about in. below the surface of the liquid, blowing perpendicularly downward from a nozzle made of lead pipe through an aperture / in. in diameter. under these circumstances the absorption of the steam is nearly perfect, and takes place without any splashing. the temperature rises with the increasing dilution, and may be regulated by the less experienced by manipulating the cooling tank. an actual boiling is not desired, because it protracts unnecessarily the operation by the less perfect condensation of the steam. no separation of silver sulphate occurs during this operation (and, consequently, there is no clotting of the steam nozzle), the large amount of free acid, combined with the increase of temperature, compensating for the diminution of the solubility of the sulphate by the dilution. the most important point in this procedure is to know when to stop the admission of steam. to determine this, the operator takes a drop or two of the solution upon a cold iron plate by means of a glass rod and observes whether after cooling the sample congeals partly or wholly into a white mass of silver bisulphate, or whether the silver separates as a monosulphate in detached yellow crystals, leaving a mother liquor behind. as soon as the latter point has been reached, steam is shut off and the solution is allowed to crystallize, cold water being admitted into the outer pan. the operator may now be certain that the liquid will no longer congeal into a soft mass of silver bisulphate, which on contact with water will disintegrate into powder, obstinately retaining a large amount of free acid; but the silver will separate as a monosulphate in hard and large yellow crystals retaining no acid and preserving their physical characteristics when thrown into water. after cooling to, say, ° f., the silver sulphate will have coated the pan c about in. thick. there will also be found a deposit of copper sulphate when the mother acid, after having been used over and over again, has been sufficiently saturated therewith. lead sulphate separates in a cloud, which, however, will hardly settle at this stage. the whole operation just described, which constitutes the most essential feature of the author's improvement upon his old process described in dr. percy's work, is a short one, as the acid requires by no means great dilution. the steam has merely to furnish enough water to dilute the free acid present to, say, ° b. areometrical determination is, of course, not possible, on account of the dissolved sulphates. _reducing the silver sulphate to fine silver._--the mother acid is pumped from c to the reservoir, b, for this purpose an iron pipe connecting the top of b with a recess in the bottom of c. the tank, b, is cast as a closed vessel, with a manhole in the top, which is ordinarily kept closed by an iron plate resting on a rubber packing. the air is exhausted from b by a steam injector, and the acid rises from c and enters b without coming in contact with any valves. the volume of fresh commercial acid necessary for another dissolving operation, say pounds, more or less, for refining pounds of bullion in a a, is lifted from some other receptacle into b in the same manner. the mixture of the two acids in b now represents the volume of acid to be employed for dissolving and settling the next charge of pounds of bullion in a a. in this reservoir, b, the cloud of lead sulphate mentioned above finds an opportunity for settling. the crystals of silver sulphate are detached from c by an iron shovel and thrown into d. d is a lead lined tank about ft. by ft. and ft. deep. it is divided into two compartments by means of a horizontal, perforated false bottom made of wood. from the lower compartment a lead pipe discharges into the lead lined reservoir, e. warm distilled water is allowed to percolate the crystals until the usual ammonia test indicates that the copper sulphate has been sufficiently dissolved. then the outflow is closed, sheets of iron are thrown on and into the crystals, the apparatus is filled with hot distilled water, and steam is moderately admitted into the lower compartment. ferrous sulphate is formed, and in connection with the iron rapidly reduces the silver sulphate to the metallic state, the reduced silver retaining the heavy compact character of the crystals. when the reaction is completed, as indicated by the chlorine test, the liquid is discharged into e, the iron sheets are removed and the silver is sweetened either in the same vessel, d, or in a special filtering vessel which rests on wheels and may be run directly to the hydraulic press. the vat, e, is the great reservoir where all liquids holding silver sulphate in solution are collected; for instance, that from sweetening the gold and from washing the tools. sheets of iron here precipitate all silver and copper, and the resulting solution of ferrous sulphate is, with the usual precautions, discharged into the sewer. occasionally when copper and silver have accumulated in e in sufficient amount the mass is thrown into d, silver sulphate crystals are added and sheet copper is thrown in, instead of sheet iron. there results a hot, neutral, concentrated solution of copper sulphate, which may be run at once into a crystallizing vat for the separation of commercial crystals of copper sulphate. it will be readily understood, of course, that if there should be any advantage in manufacturing that commercial article, besides the amount prepared as described, which represents merely the copper contained in the bullion, copper sheets may be regularly employed for reducing the silver sulphate in d. the author trusts that the practical refiner will recognize that the manufacture of commercial copper sulphate is thus effected in a more rational and economical manner than by the present method of evaporating from ° b. to ° b., and of saturating by oxidized copper, generally in a very incomplete manner, the large amount of free acid left from the refining by the usual process. however, the sale of copper sulphate is but rarely so profitable that a refinery should not gladly dispense with that troublesome and bulky manufacture, especially the government establishments, which, besides, waste much valuable space with the crystallizing vats. the great saving in sulphuric acid, amounting to about per cent. of the present consumption, has already been pointed out. another advantage the author merely mentions, namely, the easier condensation of the sulphurous fumes in refineries situated in cities, because the larger amount of acid available for dissolving greatly facilitates working and makes the usual frequent admission of air into the refining pot for the purpose of stirring and testing unnecessary. the more air is excluded from the refining fumes the easier they can be condensed. work may be carried on continuously, the vessels c and d being empty by the time a new solution is finished in a a. thus, the plant shown in the diagram, covering ft. by ft., allows the refining of , ounces of fine silver in hours; that is, four charges in a a of pounds each.--_f. gutzkow, eng. and mining j._ * * * * * a case of drowning, with resuscitation. by f.a. burrall, m.d., new york. as is usual at this season, casualties from drowning are of frequent occurrence. no class of emergencies is of a more startling character, and i think that a history of the case which i now present offers some peculiar features, and will not be without interest to physicians. the accident which forms the subject of this paper occurred august , , at south harpswell, casco bay, me., where i was passing my vacation. at about . a.m., m. b----, an american, aged eighteen, the son of a fisherman, a young man of steady habits and a good constitution, with excellent muscular development, and who had never before required the aid of a physician, was seen by the residents of the village to fall forward from a skiff into the water and go down with uplifted hands. i could not learn that he rose at all after the first submersion. two men were standing near a bluff which overlooked the bay, and after an instant's delay in deciding that an accident had occurred, they ran over an uneven and undulating pasture for a distance of two hundred and fifty paces to the shore. one of them, after a quick decision not to swim out to where the young man had fallen in and dive for him, removed trousers and boots and waded out five yards to a boat, which he drew into the shore and entered with his companion, taking him to a yacht which lay two hundred and forty yards from the shore, in the padlocked cabin of which was a boat hook. the padlock was unfastened, the boat hook taken, and they proceeded by the boat directly to where the young man lay. he was seen through the clear water, lying at a depth of nine feet at the bottom of the bay, on his back, with upturned face and arms extended from the sides of the body. he was quickly seized by the boat hook, drawn head upward to the surface, and with the inferior portion of the body hanging over the stern of the boat, and the superior supported in the arms of his rescuer, was rowed rapidly to the shore, where he was rolled a few times, and then placed prone upon a tub for further rolling. i was told that much water came from his mouth. meantime i had been sent for to where i was sitting, one hundred and fifty-one yards from the scene, and i arrived to find him apparently lifeless on the tub, and to be addressed with the remark, "well, doctor, i suppose we are doing all that can be done." i have given these details, as from a study of them i was aided in deciding the time of submersion, as well as the intervals which transpired before the intelligent use of remedies. it is also remarkable that, notwithstanding all which has been written about ready remedies for drowning, no one present knew anything about them, although living in a seafaring community. i immediately directed that the patient should at once be placed upon the ground, which was sloping, and arranged his rubber boots under the back of the head and nape of the neck, so that the head should be slightly elevated and the neck extended, while the head was turned somewhat upon the side, that fluids might drain from the mouth. the day was clear and moderately warm. respiration had ceased, but no time was lost in commencing artificial respiration. the patient had on a shirt and pantaloons, which were immediately unbuttoned and made loose, and placing myself at his head, i used the silvester method, because i was more accustomed to it than any other. it seems to me more easy of application than any other, and i have often found it of service in the asphyxia of the newly born. the patient's surface was cold, there was extensive cyanosis, and his expression was so changed that he was not recognized by his fellow townsmen, but supposed to be a stranger. the eyelids were closed, the pupils contracted, and the inferior maxilla firmly set against the superior. one of the men who had brought him ashore had endeavored to find the heart's impulse by placing his hand upon the chest, but was unable to detect any motion. i continued the artificial respiration from . until , when i directed one of his rescuers to make pressure upon the ribs, as i brought the arms down upon the chest. this assistance made expiration more complete. when nature resumed the respiratory act i am unable to say, but the artificial breathing was continued in all its details for three-quarters of an hour, and then expiration was aided by pressure on the chest for half an hour longer. friction upward was also applied to the lower extremities, and the surface became warm about half an hour after the beginning of treatment. about twenty minutes after ten, two hypodermic syringefuls of brandy were administered, but i did not repeat this, since i think alcohol is likely to increase rather than diminish asphyxia, if given in any considerable quantity. a thermometer, with the mercury shaken down below the scale, at this time did not rise. at . the pulse was ; respiration, ; temperature, . after a natural respiration had commenced, the wet clothing was removed, and the patient was placed in blankets. ammonia was occasionally applied to the nostrils, since, although respiration had returned, there was no sign of consciousness; the natural respiration was at first attended by the expulsion of frothy fluid from the lips, which gradually diminished, and auscultation revealed the presence of a few pulmonary rales, which also passed away. there were efforts at vomiting, and pallor succeeded cyanosis; there were also clonic contractions of the flexors of the forearm. the pupils dilated slightly at about one hour after beginning treatment. unconsciousness was still profound, and loud shouting into the ear elicited no response. mustard sinapisms were applied to the præcordium, and the faradic current to the spine. coffee was also administered by a ready method which, as a systematic procedure, was, i believe, novel when i introduced it to the profession in the _medical record,_ in . i take the liberty of referring to this, since i think it is now sometimes overlooked. it was described as follows: "a simple examination which any one can make of his own buccal cavity will show that posterior to the last molar teeth, when the jaws are closed, is an opening bounded by the molars, the body of the superior, and the ramus of the inferior maxilla. if on either side the cheek is held well out from the jaw, a pocket, or gutter, is formed, into which fluids may be poured, and they will pass into the mouth through the opening behind the molars, as well as through the interstices between the teeth. when in the mouth they tend to create a disposition to swallow, and by this method a considerable quantity of liquid may be administered." after i had worked with the patient in the open air, for four and three-quarter hours, he was carried to a cottage near by and placed, still unconscious, in bed. there had been an alvine evacuation during the time in which he lay in the blankets. consciousness began to return in the early part of the following morning, and with its advent it was discovered that the memory of everything which had occurred from half an hour previous to the accident, up to the return of consciousness, had been completely obliterated. with this exception the convalescence was steady and uncomplicated, and of about a week's duration. from a letter which i recently received from my patient, i learned that the lapse of memory still remains. my experience with this case has taught me that, unless the data have been taken very accurately, we cannot depend upon any statements as to the time of submersion in cases of drowning. my first supposition was that my patient had been from thirteen to fifteen minutes under water, but a careful investigation reduced the supposed time by one-half. this makes the time of submersion about six minutes, and that which elapsed before the intelligent use of remedies about three minutes longer. for a long time the opinion of sir benjamin brodie concerning the presence of water in the lungs of the drowned was accepted, who says "that the admission of water into the lungs is prevented by a spasm of the muscles of the glottis cannot, however, be doubted, since we are unable to account for it in any other manner." later experiments made by a committee of the royal medico-chirurgical society, of london, demonstrated, on the contrary, that "in drowned animals not only were all the air passages choked with frothy fluid, more or less bloody, but that both lungs were highly gorged with blood, so that they were heavy, dark colored, and pitted on pressure, and on being cut exuded an abundance of blood-tinged fluid with many air bubbles in it." dr. r.l. bowles[ ] also holds that the lungs of the drowned contain water, and supports his views by a list of cases. in his words, "these examples show very conclusively that in cases of drowning in man, water does exist in the lungs, that the water only very gradually and after a long time is effectually expelled, and that it is absolutely impossible that any relief should be afforded in that way by the silvester method." dr. bowles believes that the method of dr. marshall hall is superior to any other in this class of cases. he thinks that on account of the immediate adoption and continued use of the prono-lateral position, this method is more to be trusted than any other for keeping the pharynx clear of obstruction. "it also empties the stomach and gradually clears the lungs of the watery and frothy fluids, and will surely and gently introduce sufficient air at each inspiration to take the place of the fluid which has been expelled." in the light of even my limited experience i cannot but feel that dr. bowles' opinion concerning the silvester method would admit of some modification. this is often the case with very positive statements concerning medical matters. in my own case the silvester method answered well, but i was much impressed with dr. bowles' claims for the marshall hall method, and should bear them in mind were i called upon to attend another case of drowning. [footnote : resuscitation of the apparently drowned, by r.l. bowles, m.d., f.r.c.p., medico-chirurgical transactions, vol. lxxii., .] i think it must be admitted that pulling the tongue forward as a means of opening the glottis, which has become a standard treatment in asphyxia, is unscientific, and not warranted by the results of experiments made to determine its value.[ ] [footnote : dragging on the tongue's tip would not affect its base or the epiglottis sufficiently to make it a praiseworthy procedure. medico-chirurgical transactions, vol. lxxii. see also _medical record_, april , . pulling out the tongue is a mistake, since irritation of nerves of deglutition stops the diaphragm.--_medical times and gazetteer._] dr. bowles also believes that "the safety of the patient is most perfectly secured by keeping him on one side during the whole treatment, one lung being thus kept quite free." with the account of my case i have brought forward such views of other writers as it seemed to me would be of practical service and throw light on a subject which is of great importance, since the yearly record of mortality from drowning is by no means inconsiderable. i think, however, that a knowledge of what ought to be done in cases of drowning should be much more generally diffused than is the case at present. it should be one of the items of school instruction, since no one can tell when such knowledge may be of immense importance in saving life, and the time lost in securing medical aid would involve a fatal result. it is also very desirable that all doubt should be removed, by the decision of competent medical authorities, as to which "ready" method or methods are the best, since there are several in the field. with this should be decided what is the best means for securing patency of the air passages, and, in short, a very careful revision of the treatment now recommended for drowning, in order that there may be no doubt as to the course which should be adopted in such a serious emergency.--_medical record._ * * * * * the story of the universe.[ ] [footnote : presidential address before the british association, cardiff, .] by dr. william huggins. the opening meeting of the british association was held in park hall, cardiff, august , where a large and brilliant audience assembled, including, in his richly trimmed official robes, the marquis of bute, who this year holds office as mayor of cardiff. at the commencement of the proceedings sir frederick abel took the chair, but this was only _pro forma_, and in order that he might, after a few complimentary sentences, resign it to the president-elect, professor huggins, the eminent astronomer, who at once, amid applause, assumed the presidency and proceeded to deliver the opening address. dr. huggins said that the very remarkable discoveries in our knowledge of the heavens which had taken place during the past thirty years--a period of amazing and ever-increasing activity in all branches of science--had not passed unnoticed in the addresses of successive presidents; still, it seemed to him fitting that he should speak of those newer methods of astronomical research which had led to those discoveries, and which had become possible by the introduction into the observatory, since , of the spectroscope and the modern photographic plate. spectroscopic astronomy had become a distinct and acknowledged branch of the science, possessing a large literature of its own, and observatories specially devoted to it. the more recent discovery of the gelatine dry plate had given a further great impetus to this modern side of astronomy, and had opened a pathway into the unknown of which even an enthusiast thirty years ago would scarcely have dared to dream. herschel's theory. it was now some thirty years since the spectroscope gave us for the first time certain knowledge of the nature of the heavenly bodies, and revealed the fundamental fact that terrestrial matter is not peculiar to the solar system, but is common to all the stars which are visible to us. professor rowland had since shown us that if the whole earth were heated to the temperature of the sun, its spectrum would resemble very closely the solar spectrum. in the nebulæ, the elder herschel saw portions of the fiery mist or "shining fluid," out of which the heavens and the earth had been slowly fashioned. for a time this view of the nebulæ gave place to that which regarded them as external galaxies--cosmical "sand heaps," too remote to be resolved into separate stars, though, indeed, in , mr. herbert spencer showed that the observations of nebulæ up to that time were really in favor of an evolutional progress. in he (the speaker) brought the spectroscope to bear upon them; the bright lines which flashed upon the eye showed the source of the light to be glowing gas, and so restored these bodies to what is probably their true place, as an early stage of sidereal life. at that early time our knowledge of stellar spectra was small. for this reason partly, and probably also under the undue influence of theological opinions then widely prevalent, he unwisely wrote in his original paper in , that "in these objects we no longer have to do with a special modification of our own type of sun, but find ourselves in presence of objects possessing a distinct and peculiar plan of structure." two years later, however, in a lecture before this association, he took a truer position. "our views of the universe," he said, "are undergoing important changes; let us wait for more facts with minds unfettered by any dogmatic theory, and, therefore, free to receive the teaching, whatever it may be, of new observations." the nebular hypothesis. let them turn aside for a moment from the nebulæ in the sky to the conclusions to which philosophers had been irresistibly led by a consideration of the features of the solar system. we had before us in the sun and planets obviously not a haphazard aggregation of bodies, but a system resting upon a multitude of relations pointing to a common physical cause. from these considerations kant and laplace formulated the nebular hypothesis, resting it on gravitation alone, for at that time the science of the conservation of energy was practically unknown. these philosophers showed how, on the supposition that the space now occupied by the solar system was once filled by a vaporous mass, the formation of the sun and planets could be reasonably accounted for. by a totally different method of reasoning, modern science traced the solar system backward step by step to a similar state of things at the beginning. according to helmholtz, the sun's heat was maintained by the contraction of his mass, at the rate of about feet a year. whether at the present time the sun was getting hotter or colder we did not certainly know. we could reason back to the time when the sun was sufficiently expanded to fill the whole space occupied by the solar system, and was reduced to a great glowing nebula. though man's life, the life of the race perhaps, was too short to give us direct evidence of any distinct stages of so august a process, still the probability was great that the nebular hypothesis, especially in the more precise form given to it by roche, did represent broadly, notwithstanding some difficulties, the succession of events through which the sun and planets had passed. [illustration: dr. william huggins, d.c.l., ll.d., president of the british association. dr. huggins is one of the most eminent astronomers of the present day, and his spectroscopic researches on the celestial bodies have had the most important results. he is a d.c.l. of oxford, ll.d. of cambridge, and ph.d of leyden. dr. huggins was born in and educated at the city of london school. he continued his studies, giving much of his time to experiments in natural philosophy and physical science. in dr. huggins erected a private observatory at his residence on tulse hill, where he has carried out valuable prismatic researches with the spectroscope.--_daily graphic._] other speculations. the nebular hypothesis of laplace required a rotating mass of fluid which at successive epochs became unstable from excess of motion, and left behind rings, or more probably, perhaps, lumps, of matter from the equatorial regions. to some thinkers was suggested a different view of things, according to which it was not necessary to suppose that one part of the system gravitationally supported another. the whole might consist of a congeries of discrete bodies, even if these bodies were the ultimate molecules of matter. the planets might have been formed by the gradual accretion of such discrete bodies. on the view that the material of the condensing solar system consisted of separate particles or masses, we had no longer the fluid pressure which was an essential part of laplace's theory. faye, in his theory of evolution from meteorites, had to throw over his fundamental idea of the nebular hypothesis, and formulated instead a different succession of events of which the outer planets were formed last, a theory which had difficulties of its own. professor george darwin had recently shown, from an investigation of the mechanical conditions of a swarm of meteorites, that on certain assumptions a meteoric swarm might behave as a coarse gas, and in this way bring back the fluid pressure exercised by one part of the system on the other, which was required by laplace's theory. one chief assumption consisted in supposing that such inelastic bodies as meteoric stones might attain the effective elasticity of a high order which was necessary to the theory through the sudden volatilization of a part of their mass at an encounter, by which what was virtually a violent explosive was introduced between the two colliding stones. professor darwin was careful to point out that it must necessarily be obscure as to how a small mass of solid matter could take up a very large amount of energy in a small fraction of a second. helmholtz's discovery. the old view of the original matter of the nebulæ, that it consisted of a "fiery mist," "a tumultuous cloud, instinct with fire and niter," fell at once with the rise of the science of thermodynamics. in , helmholtz showed that the supposition of an original fiery condition of the nebulous stuff was unnecessary, since in the mutual gravitation of widely separated matter we had a store of potential energy sufficient to generate the high temperature of the sun and stars. we could scarcely go wrong in attributing the light of the nebulæ to the conversion of the gravitational energy of shrinkage into molecular motion. the inquisitiveness of the human mind did not allow us to remain content with the interpretation of the present state of the cosmical masses, but suggested the question-- what see'st thou else in the dark backward and abysm of time? what was the original state of things? how had it come about that by the side of ageing worlds we had nebulæ in a relatively younger stage? had any of them received their birth from dark suns, which had collided into new life, and so belonged to a second or later generation of the heavenly bodies? looking backward. during the short historic period there was no record of such an event; still it would seem to be only through the collision of dark suns, of which the number must be increasing, that a temporary rejuvenescence of the heavens was possible, and by such ebbings and flowings of stellar life that the inevitable end to which evolution in its apparently uncompensated progress was carrying us could, even for a little, be delayed. we could not refuse to admit as possible such an origin for nebulæ. in considering, however, the formation of the existing nebulæ we must bear in mind that, in the part of the heavens within our ken, the stars still in the early and middle stages of evolution exceeded greatly in number those which appeared to be in an advanced condition of condensation. indeed, we found some stars which might be regarded as not far advanced beyond the nebular condition. it might be that the cosmical bodies which were still nebulous owed their later development to some conditions of the part of space where they occurred, such as conceivably a greater original homogeneity, in consequence of which condensation began less early. in other parts of space condensation might have been still further delayed, or even have not yet begun. if light matter were suggested by the spectrum of these nebulæ, it might be asked further, as a pure speculation, whether in them we were witnessing possibly a later condensation of the light matter which had been left behind, at least in a relatively greater proportion, after the first growth of worlds into which the heavier matter condensed, though not without some entanglement of the lighter substances. the wide extent and great diffuseness of this bright-line nebulosity over a large part of the constellation of orion might be regarded, perhaps, as pointing in this direction. the diffuse nebulous matter streaming round the pleiades might possibly be another instance, though the character of its spectrum had not yet been ascertained. the motions of the stars. besides its more direct use in the chemical analysis of the heavenly bodies, the spectroscope had given to us a great and unexpected power of advance along the lines of the older astronomy. in the future a higher value might, indeed, be placed upon this indirect use of the spectroscope than upon its chemical revelations. by no direct astronomical methods could motions of approach or of recession of the stars be even detected, much less could they be measured. a body coming directly toward us or going directly from us appeared to stand still. in the case of the stars we could receive no assistance from change of size or of brightness. the stars showed no true disks in our instruments, and the nearest of them was so far off that if it were approaching us at the rate of a hundred miles in a second of time, a whole century of such rapid approach would not do more than increase its brightness by the one-fortieth part. still it was formerly only too clear that, so long as we were unable to ascertain directly those components of the stars' motions which lay in the line of sight, the speed and direction of the solar motion in space, and many of the great problems of the constitution of the heavens must have remained more or less imperfectly known. now the spectroscope had placed in our hands this power, which, though so essential, had previously appeared almost in the nature of things to lie forever beyond our grasp; it enabled us to measure directly, and, under favorable circumstances, to within a mile per second, or even less, the speed of approach or of recession of a heavenly body. this method of observation had the great advantage for the astronomer of being independent of the distance of the moving body, and was, therefore, as applicable and as certain in the case of a body on the extreme confines of the visible universe, so long as it was bright enough, as in the case of a neighboring planet. algol and spica. by observations with the potsdam spectograph, professor vogel found that the bright star of algol pulsated backward and forward in the visual direction in a period corresponding to the known variation of its light. the explanation which had been suggested for the star's variability, that it was partially eclipsed at regular intervals of . hours by a dark companion large enough to cut off nearly five-sixths of its light, was, therefore, the true one. the dark companion, no longer able to hide itself by its obscureness, was brought out into the light of direct observation by means of its gravitational effects. seventeen hours before minimum algol was receding at the rate of about ½ miles a second, while seventeen hours after minimum it was found to be approaching with a speed of about ½ miles. from these data, together with those of the variation of its light, vogel found, on the assumption that both stars have the same density, that the companion, nearly as large as the sun, but with about one-fourth his mass, revolved with a velocity of about fifty-five miles a second. the bright star of about twice the size and mass moved about the common center of gravity with the speed of about miles a second. the system of the two stars, which were about ¼ millions of miles apart, considered as a whole, was approaching us with a velocity of . miles a second. the great difference in luminosity of the two stars, not less than fifty times, suggested rather that they were in different stages of condensation, and dissimilar in density. it was obvious that if the orbit of a star with an obscure companion was inclined to the line of sight, the companion would pass above or below the bright star and produce no variation of its light. such systems might be numerous in the heavens. in vogel's photographs, spica, which was not variable, by a small shifting of its lines revealed a backward and forward periodical pulsation due to orbital motion. as the pair whirled round their common center of gravity, the bright star was sometimes advancing, at others receding. they revolved in about four days, each star moving with a velocity of about miles a second in an orbit probably nearly circular, and possessed a combined mass of rather more than two and one-half times that of the sun. taking the most probable value for the star's parallax, the greatest angular separation of the stars would be far too small to be detected with the most powerful telescopes. the value of photography. referring to the new and great power which modern photography had put into the hands of the astronomer, the president said that the modern silver bromide gelatine plate, except for its grained texture, met his needs at all points. it possessed extreme sensitiveness, it was always ready for use, it could be placed in any position, it could be exposed for hours, lastly it did not need immediate development, and for this reason could be exposed again to the same object on succeeding nights, so as to make up by several installments, as the weather might permit, the total time of exposure which was deemed necessary. without the assistance of photography, however greatly the resources of genius might overcome the optical and mechanical difficulties of constructing large telescopes, the astronomer would have to depend in the last resource upon his eye. now, we could not by the force of continued looking bring into view an object too feebly luminous to be seen at the first and keenest moment of vision. but the feeblest light which fell upon the plate was not lost, but taken in and stored up continuously. each hour the plate gathered up , times the light energy which it received during the first second. it was by this power of accumulation that the photographic plate might be said to increase, almost without limit, though not in separating power, the optical means at the disposal of the astronomer for the discovery or the observation of faint objects. two examples. two principal directions might be pointed out in which photography was of great service to the astronomer. it enabled him within the comparatively short time of a single exposure to secure permanently with great exactness the relative positions of hundreds or even of thousands of stars, or the minute features of nebulæ or other objects, or the phenomena of a passing eclipse, a task which by means of the eye and hand could only be accomplished, if done at all, after a very great expenditure of time and labor. photography put it in the power of the astronomer to accomplish in the short span of his own life, and so enter into their fruition, great works which otherwise must have been passed on by him as a heritage of labor to succeeding generations. the second great service which photography rendered was not simply an aid to the powers the astronomer already possessed. on the contrary, the plate, by recording light waves which were both too small and too large to excite vision in the eye, brought him into a new region of knowledge, such as the infra-red and the ultra-violet parts of the spectrum, which must have remained forever unknown but for artificial help. a photographic chart. the present year would be memorable in astronomical history for the practical beginning of the photographic chart and catalogue of the heavens which took their origin in an international conference which met in paris in . the decisions of the conference in their final form provided for the construction of a great chart with exposures corresponding to forty minutes' exposure at paris, which it was expected would reach down to stars of about the fourteenth magnitude. as each plate was to be limited to four square degrees, and as each star, to avoid possible errors, was to appear on two plates, over , photographs would be required. a second set of plates for a catalogue was to be taken, with a shorter exposure, which would give stars to the eleventh magnitude only. the plans were to be pushed on as actively a possible, though as far as might be practicable plates for the chart were to be taken concurrently. photographing the plates for the catalogue was but the first step in this work, and only supplied the data for the elaborate measurements which would have to be made, which were, however, less laborious than would be required for a similar catalogue without the aid of photography. a delicate operation. the determination of the distances of the fixed stars from the small apparent shift of their positions when viewed from widely separated positions of the earth in its orbit was one of the most refined operations of the observatory. the great precision with which this minute angular quantity, a fraction of a second only, had to be measured, was so delicate an operation with the ordinary micrometer, though, indeed, it was with this instrument that the classical observations of sir robert ball were made, that a special instrument, in which the measures were made by moving the two halves of a divided object glass, known as a heliometer, had been pressed into this service, and quite recently, in the skillful hands of dr. gill and dr. elkin, had largely increased our knowledge in this direction. it was obvious that photography might be here of great service, if we could rely upon measurements of photographs of the same stars taken at suitable intervals of time. professor pritchard, to whom was due the honor of having opened this new path, aided by his assistants, had proved by elaborate investigations that measures for parallax might be safely made upon photographic plates, with, of course, the advantages of leisure and repetition; and he had already by this method determined the parallax for twenty-one stars with an accuracy not inferior to that of values previously obtained by purely astronomical methods. photographic revelations. the remarkable successes of astronomical photography, which depended upon the plate's power of accumulation of a very feeble light acting continuously through an exposure of several hours, were worthy to be regarded as a new revelation. the first chapter opened when, in , dr. henry draper obtained a picture of the nebula of orion; but a more important advance was made in , when dr. common, by his photographs, brought to our knowledge details and extensions of this nebula hitherto unknown. a further disclosure took place in , when the brothers henry showed for the first time in great detail the spiral nebulosity issuing from the bright star maia of the pleiades, and shortly afterward nebulous streams about the other stars of this group. in mr. roberts, by means of a photograph to which three hours' exposure had been given, showed the whole background of this group to be nebulous. in the following year mr. roberts more than doubled for us the great extension of the nebular region which surrounds the trapezium in the constellation of orion. by his photographs of the great nebula in andromeda, he had shown the true significance of the dark canals which had been seen by the eye. they were in reality spaces between successive rings of bright matter, which appeared nearly straight, owing to the inclination in which they lay relatively to us. these bright rings surrounded an undefined central luminous mass. recent photographs by mr. russell showed that the great rift in the milky way in argus, which to the eye was void of stars, was in reality uniformly covered with them. the story of the heavens. the heavens were richly but very irregularly inwrought with stars. the brighter stars clustered into well known groups upon a background formed of an enlacement of streams and convoluted windings and intertwined spirals of fainter stars, which became richer and more intricate in the irregularly rifted zone of the milky way. we, who formed part of the emblazonry, could only see the design distorted and confused; here crowded, there scattered, at another place superposed. the groupings due to our position were mixed up with those which were real. could we suppose that each luminous point had no relation to the others near it than the accidental neighborship of grains of sand upon the shore, or of particles of the wind-blown dust of the desert? surely every star from sirius and vega down to each grain of the light dust of the milky way had its present place in the heavenly pattern from the slow evolving of its past. we saw a system of systems, for the broad features of clusters and streams and spiral windings marking the general design were reproduced in every part. the whole was in motion, each point shifting its position by miles every second, though from the august magnitude of their distances from us and from each other, it was only by the accumulated movements of years or of generations that some small changes of relative position revealed themselves. the work of the future. the deciphering of this wonderfully intricate constitution of the heavens would be undoubtedly one of the chief astronomical works of the coming century. the primary task of the sun's motion in space, together with the motions of the brighter stars, had been already put well within our reach by the spectroscopic method of the measurement of star motions in the line of sight. astronomy, the oldest of the sciences, had more than renewed her youth. at no time in the past had she been so bright with unbounded aspirations and hopes. never were her temples so numerous, nor the crowd of her votaries so great. the british astronomical association formed within the year numbered already about members. happy was the lot of those who were still on the eastern side of life's meridian! already, alas! the original founders of the newer methods were falling out--kirchhoff, angstrom, d'arrest, secchi, draper, becquerel; but their places were more than filled; the pace of the race was gaining, but the goal was not and never would be in sight. since the time of newton our knowledge of the phenomena of nature had wonderfully increased, but man asked perhaps more earnestly now than in his days, what was the ultimate reality behind the reality of the perceptions? were they only the pebbles of the beach with which we had been playing? did not the ocean of ultimate reality and truth lie beyond? * * * * * climatic changes in the southern hemisphere. by c.a.m. taber. having had occasion to cruise a considerable time over the southern ocean, i have had my attention directed to its prevailing winds and currents, and the way in which they affect its temperature, and also to the ice-worn appearance of its isolated lands. it is now generally conceded that the lands situated in the high latitudes of the southern hemisphere have in the remote past been covered with ice sheets, similar to the lands which lie within the antarctic circle. the shores of southern chile, from latitude ° to cape horn, show convincing evidence of having been overrun by heavy glaciers, which scoured out the numerous deep channels that separate the patagonian coast from its islands. the falkland islands and south georgia abound with deep friths; new zealand and kerguelen land also exhibit the same evidence of having been ice-laden regions; and it is said that the southern lands of africa and australia show that ice accumulated at one time to a considerable extent on their shores. at this date we find the southern ice sheets mostly confined to regions within the antarctic circle; still the lands of chile, south georgia, and new zealand possess glaciers reaching the low lands, which are probably growing in bulk; for it appears that the antarctic cold is slowly on the increase, and the reasons for its increase are the same as the causes which brought about the frigid period which overran with ice all lands situated in the high southern latitudes. why there should be a slow increase of cold on this portion of the globe is because of the independent circulation of the waters of the southern ocean. the strong westerly winds of the southern latitudes are constantly blowing the surface waters of the sea from west to east around the globe. this causes an effectual barrier, which the warm tropical currents cannot penetrate to any great extent. for instance, the tropical waters of the high ocean levels, which lie abreast brazil in the atlantic and the east coast of africa in the indian ocean, are not attracted far into the southern sea, because the surface waters of the latter sea are blown by the westerly winds from west to east around the globe. consequently the tropical waters moving southward are turned away by the prevailing winds and currents from entering the southern ocean. thus the ice is accumulating on its lands, and the temperature of its waters slowly falling through their contact with the increasing ice; and such conditions will continue until the lands of the high southern latitudes are again covered with glaciers, and a southern ice period perfected. but while this gathering of ice is being brought about, the antarctic continent, now nearly covered with an ice sheet, will, through the extension of glaciers out into its shallow waters, cover a larger area than now; for where the waters are shoal the growing glaciers, resting on a firm bottom, will advance into the sea, and this advancement will continue wherever the shallow waters extend. especially will this be the case where the snowfall is great. under such conditions, it appears that the only extensive body of shallow water extending from the ice-clad southern continent is the shoal channel which separates the south shetlands from cape horn, which is a region of great snowfall. therefore, should the antarctic ice gain sufficient thickness to rest on the bottom of this shallow sea, it would move into the cape horn channel, and eventually close it. the ice growth would not be entirely from the southern continent, but also from lands in the region of cape horn. thus the antarctic continent and south america would be connected by an isthmus of ice, and consequently the independent circulation of the southern ocean arrested. hence it will be seen that the westerly winds, instead of blowing the surface waters of the southern ocean constantly around the globe, as they are known to do to-day, would instead blow the surface waters away from the easterly side of the ice-formed isthmus, which would cause a low sea level along its atlantic side, and this low sea level would attract the tropical waters from their high level against brazil well into the southern seas, and so wash the antarctic continent to the eastward of the south shetlands. the tropical waters thus attracted southward would be cooler than the tropical waters of to-day, owing to the great extension of cold in the southern latitudes. still they would begin the slow process of raising the temperature of the southern ocean, and would in time melt the ice in all southern lands. not only the brazil currents would penetrate the southern seas, as we have shown, but also the waters from the high level of the tropical indian ocean which now pass down the mozambique channel would reach a much higher latitude than now. the ice-made isthmus uniting south america to the antarctic continent would on account of its location be the last body of ice to melt from the southern hemisphere, it being situated to windward of the tropical currents and also in a region where the fall of snow is great; yet it would eventually melt away, and the independent circulation of the southern ocean again be established. but it would require a long time for ice sheets to again form on southern lands, because of the lack of icebergs to cool the southern waters. still, their temperature would gradually lower with the exclusion of the tropical waters, and consequently ice would slowly gather on the antarctic lands. the above theory thus briefly presented to account for the climatic changes of the high southern latitudes is in full accord with the simple workings of nature as carried on to-day; and it is probable that the formation of continents and oceans, as well as the earth's motions in its path around the sun, have met with little change since the cold era iced the lands of the high latitudes. at an early age, previous to the appearance of frigid periods, the ocean waters of the high latitudes probably did not possess an independent circulation sufficient to lower the temperature so that glaciers could form. this may have been owing to the shallow sea bottom south of cape horn having been above the surface of the water, the channel having since been formed by a comparatively small change in the ocean's level. for, while considering this subject, it is well to keep in mind that whenever the western continent extended to the antarctic circle it prevented the independent circulation of the southern ocean waters, consequently during such times ice periods could not have occurred in the southern hemisphere. it will be noticed that according to the views given above, the several theories which have been published to account for great climatic changes neglect to set forth the only efficacious methods through which nature works for conveying and withdrawing tropical heat sufficient to cause temperate and frigid periods in the high latitudes. while lack of space forbids an explanation of the causes which would perfect an ice period in the northern hemisphere, i will say that it could be mainly brought about through the independent circulation of the arctic waters, which now largely prevent the tropical waters of the north atlantic from entering the arctic seas, thus causing the accumulation of ice sheets on greenland. but before a northern ice period can be perfected, it seems that it will need to co-operate with a cold period in the southern hemisphere; and in order to have the ice of a northern frigid period melt away, it would require the assistance of a mild climate in the high southern latitudes.--_science_. * * * * * ammonia. in the majority of refrigerating and ice machines ammonia gas is the substance used for producing the refrigeration, although there are other machines in which other material is employed, one of these being anhydrous sulphurous acid, which is also a gas. ammonia of itself is a colorless gas, but little more than one half as heavy as air. in its composition ammonia consists of two gases, nitrogen and hydrogen, in the proportion by weight of one part nitrogen and three parts hydrogen. the gas hydrogen is one of the constituents of water and is highly inflammable in the presence of air or oxygen, while the other component of ammonia, nitrogen, forms the bulk or about four-fifths of the atmosphere. nitrogen by itself is an inert gas, colorless and uninflammable. ammonia, although composed of more than three-fourths its weight of hydrogen, is not inflammable in air, on account of its combination with the nitrogen. this combination, it will be understood, is not a simple mixture, but the two gases are chemically combined, forming a new substance which has characteristics and properties entirely different from either of the gases entering into its composition when taken alone or when simply mixed together without chemical combustion. ammonia cannot be produced by the direct combination of these elements, but it has been found that it is sometimes made or produced in a very extraordinary manner, which goes to show that there is yet considerable to be learned in regard to the chemistry of ammonia. animal or vegetable substances when putrefying or suffering destructive distillation almost invariably give rise to an abundant production of this substance. the common method for the manufacture of ammonia is to produce it from the salt known as sal-ammoniac. sal-ammoniac as a crystal is obtained in various ways, principally from the ammoniacal liquor of gas works, also from the condensed products of the distillation of bones and other animal refuse in the preparation of animal charcoal, and which is of a highly alkaline nature. this liquid is then treated with a slight excess of muriatic acid to neutralize the free alkali, and at the same time the carbonates and sulphides are decomposed with the evolution of carbonic acid and sulphureted hydrogen. all animal matter, the meat, bones, etc., contain considerable carbon, while the nitrogen from which the ammonia is produced forms a smaller portion of the substance. the object is then to get rid of the carbon and sulphur, leaving the nitrogen to combine, through chemical affinity, with a portion of the hydrogen of the water, the oxygen which is set free going to form the carbonic acid by combining with the carbon. the liquor after being neutralized is evaporated to dryness, leaving a crystallized salt containing a portion of tarry matter. the salt is then purified by sublimation, that is, it is heated in a closed iron vessel until it is transformed into a gas which separates and leaves, in a carbonized state, all foreign substance. after this gas is cooled, it condenses and again forms crystals which are in a much purer condition. if necessary to further purify it, it is again sublimed. the iron vessels in which the sublimation takes place are lined with clay and covered with lead. the clay lining and lead covering are necessary, for if the gas evolved during the process of sublimation came in contact with the iron surface, the gas would be contaminated and the iron corroded. sublimed sal-ammoniac has a fibrous texture and is tough and difficult to powder. it has a sharp, salty taste and is soluble in two and a half parts of cold and in a much smaller quantity of hot water. during the process of sublimation the ammonia is not decomposed. but there are several ways in which the gas may be decomposed, and a certain portion of it is decomposed in the ordinary use of it in refrigerating machines. if electric sparks are passed through the gas, it suffers decomposition, the nitrogen and hydrogen then being in the condition of a simple mixture. when decomposed in this manner, the volume of the gas is doubled and the proportion is found to be three measures of hydrogen to one of nitrogen, while the weight of the two constituents is in the proportion of three parts hydrogen to fourteen of nitrogen. the ammonia gas may also be decomposed by passing through a red hot tube, and the presence of heated iron causes a slight degree of decomposition. this sal-ammoniac is powdered and mixed with moist slaked lime and then gently heated in a flask, when a large quantity of gaseous ammonia is disengaged. the gas must be collected over mercury or by displacement. the gas thus produced has a strong, pungent odor, as can easily be determined by any one working around the ammonia ice or refrigerating machines, for as our friend, otto luhr, says, "it is the worst stuff i ever smelled in my life." the gas is highly alkaline and combines readily with acids, completely neutralizing them, and the aqua ammonia is one of the best substances to put on a place burned by sulphuric acid, as has been learned by those working with that substance, for although aqua ammonia of full strength is highly corrosive and of itself will blister the flesh, yet when used to neutralize the effect of a burn from sulphuric acid its great affinity for the acid prevents it from injuring the skin under such conditions. the distilled gas, such as has just been described, is the anhydrous ammonia used in the compressor system of refrigeration, while it is the aqua ammonia that is used in the absorption system of refrigeration. aqua ammonia or liquor ammonia is formed by dissolving the ammonia gas in water. one volume of water will dissolve seven hundred times its bulk of this gas, and is then known as aqua ammonia, in contradistinction to anhydrous ammonia, the latter designating term meaning without water, while the term aqua is the latin word for water. anhydrous ammonia, the gas, may be reduced to the liquid form at ordinary temperatures when submitted to a pressure of about pounds. during the process of liquefaction the ammonia gives up a large amount of heat, which if absorbed or radiated while the ammonia is in the liquid condition, the gas when allowed to expand will absorb from its surroundings an amount of heat equal to that radiated, producing a very great lowering of temperature. it is this principle that is utilized in refrigeration and ice making. in the absorption system, where aqua ammonia is used, the liquor is contained in a retort to which heat is applied by means of a steam coil, and a great part of the gas which was held in solution by the water is expelled, and carries with it a small amount of water or vapor. this passes into a separator in the top of a condenser, from which the water returns again to the retort, the ammonia gas, under considerable pressure, passing into the coolers. these are large receptacles in which the gas is permitted to expand. by such expansion heat is absorbed and the temperature of the surroundings is lowered. from the coolers the gas returns to the absorber, from which it is pumped, in liquid form, into the retort, to be again heated, the gas expelled and the process repeated. as the gas passes through the different processes, being heated under pressure, cooled, expanded again, more or less decomposition takes place, presumably from a combination of a small portion of the nitrogen with vegetable, animal, or mineral matter that finds its way into the system. such decomposition, with the loss of nitrogen, leaves a small portion of free hydrogen, which is the gas that can be drawn from the top of the absorber, ignited and burned. the presence of hydrogen gas in the absorber is not necessarily detrimental to the effectiveness of the system, but as hydrogen does not possess the qualities of absorbing heat in the same way and to the same extent as ammonia, the presence of hydrogen makes the operation of the apparatus somewhat less efficient.--_stationary engineer._ * * * * * the refrigerating apparatus illustrated and described in the scientific american supplement of june , no. , is substantially that patented by messrs. erny, subers & hoos, of philadelphia. the illustration was copied from their patents of november and february last. * * * * * a new catalogue of valuable papers contained in scientific american supplement during the past ten years, sent _free of charge_ to any address. munn & co., broadway, new york. * * * * * the scientific american architects and builders edition. $ . a year. single copies, cts. this is a special edition of the scientific american, issued monthly--on the first day of the month. each number contains about forty large quarto pages, equal to about two hundred ordinary book pages, forming, practically, a large and splendid magazine of architecture, richly adorned with _elegant plates in colors_ and with fine engravings, illustrating the most interesting examples of modern architectural construction and allied subjects. a special feature is the presentation in each number of a variety of the latest and best plans for private residences, city and country, including those of very moderate cost as well as the more expensive. drawings in perspective and in color are given, together with full plans, specifications, costs, bills of estimate, and sheets of details. no other building paper contains so many plans, details, and specifications regularly presented as the scientific american. hundreds of dwellings have already been erected on the various plans we have issued during the past year, and many others are in process of construction. architects, builders, and owners will find this work valuable in furnishing fresh and useful suggestions. all who contemplate building or improving homes, or erecting structures of any kind, have before them in this work an almost _endless series of the latest and best examples_ from which to make selections, thus saving time and money. many other subjects, including sewerage, piping, lighting, warming, ventilating, decorating, laying out of grounds, etc., are illustrated. an extensive compendium of manufacturers' announcements is also given, in which the most reliable and approved building materials, goods, machines, tools, and appliances are described and illustrated, with addresses of the makers, etc. the fullness, richness, cheapness, and convenience of this work have won for it the largest circulation of any architectural publication in the world. a catalogue of valuable books on architecture, building, carpentry, masonry, heating, warming, lighting, ventilation, and all branches of industry pertaining to the art of building, is supplied free of charge, sent to any address. munn & co., publishers, broadway, new york. * * * * * building plans and specifications. in connection with the publication of the building edition of the scientific american, messrs. munn & co. furnish plans and specifications for buildings of every kind, including churches, schools, stores, dwellings, carriage houses, barns, etc. in this work they are assisted by able and experienced architects. full 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the principal countries of the world. munn & co., solicitors of patents, broadway, new york. branch offices.--nos. and f street, pacific building, near th street, washington, d.c. proofreading team. [illustration] scientific american supplement no. new york, december , scientific american supplement. vol. vol. xx, no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. engineering, etc.--steel structures.--best use of different grades of steel.--from a paper by mr. jas. christie. natural gas fuel and its application to manufacturing: purposes.--paper read before the iron and steel institute by mr. andrew carnegie.--first use of the gas.--wells near pittsburg.--extent of territory underlain with gas.--cost of piping.--analyses ofnatural gas. a gas engine water supply alarm.-- figure. the water supply of ancient roman cities.--an address by prof. w.h. corfield.--aqueducts for the supply of borne.--the aqueduct bridge pont du gard.--the supply of lyons.--construction of underground aqueducts. steam engine economy.--by chief engineer j. lowe, u.s.n.--with diagram. the "elastic limit" in metals.--selection of wire for suspension bridges, etc. prices of metals in and .--with table. ii. technology.--a method of measuring the absolute sensitiveness of photographic dry plates.--by wm. h. pickering.--from the proceedings of the academy of arts and sciences. soldering and repairing platinum vessels in the laboratory.--by j.w. pratt. the helicoidal or wire stone saw invented by m.p. gay.--with engraving of quarry showing application of saw, and figures. portable prospecting drill and automatic safety gear shown at the inventions exhibition.--with engravings. iii. electricity, etc.--electricity in warfare.--by lieutenant b.a. fiske, u.s.n.--electrical torpedoes.--torpedo detecter.--military telegraphy and telephony.--electricity for firing great guns.--arrangement of wires for lights.--the search light.--incandescent lamps for sight signaling.--electrical launches.--an "electric sight". meucci's claims to the telephone.--with description of his instrument and figures. an electric centrifugal machine for laboratories.--by alex. watt.--from paper read before the british association.-- figure. transmission of power by electricity.--experiments of m. marcel deprez. iv. art and architecture.--quadriga for the new house of parliament at vienna.--an engraving. glazed ware finial.--with engraving. hotel de ville, st. quentin.--with engraving. fire doors in mills.--from a lecture before the franklin institute by c.j. hexamer. v. natural history, etc.--preservation of insects. an accomplished parrot. the roscoff zoological laboratory.--the buildings and rooms.--the aquarium.--course of study. the murænæ at the berlin aquarium.--with engraving. metamorphosis of arctic insects. vi. medicine. etc.--a year's scientific progress in nervous and mental diseases.--by prof. l.a. merriam.--report to the nebraska state medical society. scaring the baby out. vii. miscellaneous.--wage earners and their houses.--manufacturers as landlords.--experiments of pullman, owen, peabody, and others. the locked and corded box trick, with directions for making the box.--by d b. adamson.-- figures. a perpetual calendar.--with engraving. * * * * * preservation of insects. to remove the verdigris which forms upon the pins, the pinned insects should be immersed in benzine and left there for a time; several hours is generally long enough. the administration of this bath cannot be too highly recommended for beetles which have been rendered unrecognizable by grease, especially when dust has been mixed with the grease. this immersion, of variable duration according to circumstances, will restore to these insects, however bad they have become, all their brilliancy and all their first freshness, and the efflorescences of cupric oxide will not reappear. this preventive and curative method is also readily applicable to beetles glued upon paper which have become greasy; plunge them into benzine in the same way, and as the gum is insoluble in the liquid, they remain fastened to their supports. pruinose beetles, which are few in number, are the only ones that benzine can alter; the others, which are glabrous, pubescent, or scaly, can only gain by the process, and they will always make a good show in the collection.--_a. dubois in feuille des jeunes naturatistes_, march, , p. .--_psyche_. * * * * * quadriga for the new house of parliament, at vienna. [illustration: quadriga for the new house of parliament, at vienna.] the new house of parliament at vienna is known as one of the finest specimens of pure greek architecture erected in this century; and throughout the entire building great pains have been taken to ornament the same as elaborately as is consistent with good taste. the main buildings are provided with corner pavilions, the atticas of which project over the roofs, and these atticas and other parts of the buildings are to be surmounted by quadrigas, one of which is shown in the annexed cut, taken from the _illustrirte zeitung_. this group was modeled by v. pilz, of vienna, and represents a winged goddess in a chariot drawn by four spirited steeds harnessed abreast. she holds a wreath in her raised right hand, and her left hand is represented as holding the lines for guiding the horses. the group is full of expression and life, and will add greatly to the beauty of the building to be surmounted by it. * * * * * the strongest wood in the united states, according to professor sargent, is that of the nutmeg hickory of the arkansas region, and the weakest the west indian birch _(rur seva_). the most elastic is the tamarack, the white or shellbark hickory standing far below it. the least elastic and the lowest in specific gravity is the wood of the _ficus aurea_. the highest specific gravity, upon which in general depends value as fuel, is attained by the bluewood of texas _(condalia obovata_). * * * * * glazed ware finial. [illustration: glazed ware finial.] this grand th century finial is a fine example of french ceramic ware, or glazed terracotta, and it is illustrated both by geometrical elevation and a cross sectional drawing. this latter shows the clever building up of the structure by means of a series of five pieces, overlapping each other, and kept rigid by means of a stout wrought-iron upright in the center, bolted on to the ridge, and strapped down on the hip pieces. its outline is well designed for effect when seen at a distance or from below, and its glazed surface heightens the artistic colorings, giving it a brilliant character in the sunlight, as well as protecting the ware from the action of smoke and weather.--_build. news_. * * * * * wage earners and their houses. manufacturers as landlords. among the more prominent movements of the day for the improvement of the condition of the working men are those which are growing into fashion with large manufacturing incorporations. their promise lies immediately in the fact that they call for no new convictions of political economy, and hence have nothing disturbing or revolutionary about them. accepting the usages and economical principles of industrial life, as the progress of business has developed them, an increasing number of large manufacturers have deemed it to their interest not only to furnish shops and machinery for their operatives, but dwellings as well, and in some instances the equipments of village life, such as schools, chapels, libraries, lecture and concert halls, and a regime of morals and sanitation. probably the most expensive investment of this sort in the united states, if not in the world, by any single company, is that of pullman, on lake calumet, a few miles south of chicago, an enterprise as yet scarcely five years old. it is by no means a novel undertaking, except in the magnitude, thoroughness, and unity of the scheme. twenty years ago the managers of the lonsdale mills, in rhode island, were erecting cottages on a uniform plan and maintaining schools and religious services for their operatives. more recent but more extensive is the village of the ponemah cotton mill, near taftville, conn. these are illustrations merely of similar investments upon a smaller scale elsewhere. but the european examples are older, such as robert owen's experiment at new lanark in scotland, saltaire in yorkshire, dollfuss' mulhausen quarter in alsace, and m. godin's community in the french village of guise, which are among the more familiar instances of investments originally made on business principles, with a view to the improved conditions of workmen. new lanark failed as a commercial community through the visionary character of its founder; the godin works at guise have passed into the co-operative phase within the past five years, but saltaire and mulhausen still retain their proprietary business features. the class of ventures of which these instances are but the more conspicuous examples has peculiar characteristics. they differ from the peabody and waterlow buildings of london, described in _bradstreet's_ last august, from starr's philadelphia dwellings, and from the operations of the "improved dwellings association" of new york in these particulars: the latter are financially a pure question of direct investment; are mainly concerned with life among the poor of cities, and, whatever philanthropy may be in their motive, are capable of adaptation to any class of citizens. the former, while investments also, are composite, the business of manufacturing being associated with that of rent collecting and sharing its profits and losses; their field of operations is almost invariably rural, and tenancy is restricted to the employes of the proprietor. on the other hand, they differ from all co-operative and socialistic communities in that they are an adaptation to existing circumstances, propose to demonstrate no new theories of economics, are free from all religious bonds, do not depend on any unity of opinion, and do not touch the question of the proper distribution of wealth. it is, of course, no new thing for owners of large factories, particularly in country districts, to furnish tenements for their operatives, and oftentimes it is quite indispensable that they should, because there would otherwise be no accommodation for their workmen. what is recent and exceptional is the spread of the belief that it pays to make the accommodations furnished healthful, convenient, and attractive. the sources of profit from this careful provision are these: the proprietors have control of the territory, and are able to prescribe regulations which keep out the saloon and disreputable characters, and at once there is a saving in police and court and poor taxes; for the same reason the workmen are more regular and steady in their labor, for there is no st. monday holiday, nor confused head and uncertain hand; the tenants are better able to pay their rents, and when their landlord and employer are the same person, he collects his rent out of the wages; the superior accommodations and more settled employment act strongly against labor strikes. it will be seen that the larger and better product of labor is a great factor in the profitableness of such enterprises, and that it arises from the improved character of the laborer, on the same principle that a farmer's stock pays him best when it is of good breed, is warmly housed, and well fed. against the operations of the london peabody and waterlow funds it has been alleged that they dispossess the poor shiftless tenant and bring in a new class, so that they do not improve the condition of their tenants, but afford opportunity for better ones to cheapen the price of their accommodations. the manufacturing landlord cannot wholly do this, because the first thing he has to consider is whether the applicant for a dwelling is a good workman, not whether he can be trusted for his rent. his labor he must have. his outlook is to make that labor worth more to him, by placing it in the best attainable surroundings. can this be done? if so, the ends of humanity are answered as well as the purse filled, for both interests correspond. mr. pullman, who founded the enterprise on calumet lake, has uttered sentiments like these, and has proved that in this instance it does pay to make his workmen's families comfortable, and secure from sickness and temptation. as a financial operation pullman is profitable. there are now , dwellings, either separate or in apartment houses, in this town, where five years ago the prairie stretched on every side unbroken. every tenement is connected with common sewerage, water, and gas systems, in which the most scientific principles and expert skill have been applied. the price of tenements ranges from $ per month for two rooms in an apartment house to $ for a separate dwelling of five rooms; but there is a different class of houses for clerks, superintendents, and overseers. the average price per room is $ . a month, or nearly twelve per cent. higher than in massachusetts manufacturing towns, where it is $ . . taking each tenement at an average of three rooms, this rate will pay six per cent. on an investment of $ , , , without taking into account taxes and repairs, or say six per cent. on $ , , . but one source of profit of great moment must not be overlooked, and it is the appreciation of real estate by the increase of population. this is a small factor in a great city, at least so far as concerns the humbler grade of dwellings, but in the country it is enormous. a tract of land which has been a farm becomes a village of from , to , inhabitants. its value advances by leaps and bounds. at pullman, in addition to the shops and dwellings, there are trees and turf-bordered malls and squares, a church, a theater, a free library with reading rooms, a public hall, a market house, provided at the expense of the company. liquor can only be sold at the hotel to its guests, and then under restrictions. there is a system of public schools under a board of education, which is about the only civic organization, strictly speaking, in the community. one man suffices for police duty, and he made but fifteen arrests in the last two years. it is reported that the death rate so far, including the mortality from accidents, has been under seven in , per annum. in great britain the rate is a small fraction over in , . the vital statistics of the united states show a smaller mortality than this, but they are rendered abnormal by the heavy immigration which pours into the country. emigrants are, in the language of insurance men, a selected class. they are usually at the most vigorous time of life and of hardiest and most enterprising spirit. they leave behind them the very young and the old and those enfeebled by disease or habits. to this cause must be attributed in part the exceptional record of pullman in death rate, as it is a new town. yet there can be no question that the sanitary conditions of the place are excellent. it is difficult in mixed enterprises of this nature to tell what the rate of profit upon the tenement part of the business is, since the rental and the factory react upon each other; but in the american instances quoted in this article the investment as a whole is remunerative. in the godin operations at guise, which have been co-operative for the last five years, the capital is put at $ , , , and the net earnings have averaged during that time $ , per annum, or ½ per cent. at pullman a demand has arisen on the part of the tenants for a chance to acquire proprietorship in their homes; and while the company has withheld the privilege from its original purchase of , acres, it has bought adjoining land, where it offers to advance money for building, and to take pay in monthly installments. this assimilates so much of the enterprise to that at mulhausen, and shows the drift toward a co-operative phase of capital and labor. indeed, this tendency will probably prove to be strongly characteristic of all similar schemes as fast as they attain to any magnitude. tendencies which can be resisted in communities of few hundreds become overpowering when the population rises into thousands. but from the purely commercial point of view, this drift is hardly to be deprecated, so long as the operation of selling houses returns the capital and interest safely. projects of this nature go far toward modifying the stress of antagonisms between labor and capital, because if they are successful these are harmonized to an appreciable extent, and this gives public interest to them. the eventual adjustment must come, not from convictions of duty, doctrinaire opinions, or sentiments of sympathy, but on business principles, and it is a sure step in advance to show that self-interest and philanthropy are in accord. how great the field for experiments of this nature is in the united spates may be gathered from the census of , which shows , , persons employed in the industrial establishments of the country, with an annual production of $ , , , , and a capital of nearly half that amount. of these hands and values nearly two-thirds belong to the north atlantic states,--_bradstreet's_. * * * * * hotel de ville, st. quentin. this charming building has an uncommonly well-designed facade, picturesque in the extreme, rich in detail, and thoroughly dignified. we are indebted to m. levy, of paris, for the loan of m. garen's spirited etching, from which our illustration is taken. the arcaded piazza on the ground story, the niche-spaced tier of traceried windows on the first floor, the flamboyant paneled cornice stage, and the three crowning gables over it unite in one harmonious conception, the whole elevation being finished by a central tower, while at either end of the facade two massively treated buttresses furnish a satisfactory inclosing line, and give more than a suggestion of massiveness, so necessary to render an arcaded front like this quite complete within itself; otherwise it must more or less appear to be only part of a larger building. the style is late gothic, designed when the first influence of the early renaissance was beginning to be felt through france as well as belgium, and in several respects the design has a flemish character about it. [illustration: hotel de ville, st. quentin.] st. quentin is situated on the goy, in the department of cotes du nord, and the town is seated in a picturesque valley some ten miles s.s.w. of the capital, st brieuc, which is a bishop's see, and has a small harbor near the english channel, and about thirty miles from st. malo.--_building news_. * * * * * fire doors in mills. [footnote: from a lecture before the franklin institute by c. john hexamer.] there are few parts in fire construction which are of so much importance, and generally so little understood, as fire doors. instances of the faulty construction of these, even by good builders and architects, may daily be seen. iron doors over wooden sills, with the flooring boards extending through from one building to the other, are common occurrences. we frequently find otherwise good doors hung on wooden jambs by ordinary screws. sliding doors are frequently hung on to woodwork, and all attachments are frequently so arranged that they would be in a very short time destroyed by fire, and cause the door to fall. in case of fire, a solid iron door offers no resistance to warping. in an iron lined door, on the contrary, the tendency of the sheet iron to warp is resisted by the interior wood, and when this burns into charcoal, it still resists all warping tendencies. i have seen heavily braced solid iron doors warped and turned after a fire, having proved themselves utterly worthless. it is needless to say that when wooden doors are lined, they should be lined on both sides; but frequently we find so-called fireproof doors lined on one side only. good doors are frequently blocked up with stock and other material, so that in case of fire they could not be closed without great exertion; or they have been allowed to get out of order, so that in case of fire they are useless. this has been so common that it has given rise to the jocular expression of insurance men, when they are told that a fire door exists between the two buildings, "warranted to be open in case of fire." the strictest regulations should exist in regard to closing the fire doors nightly. frequently we find that although the fire door, and its different parts, are correctly made, there are openings in the wall which would allow the fire to travel from one building to the other, such as unprotected belt and shaft holes. that a fire door may be effective, it must be hung to the only opening in the wall. the greatest care must be exercised to keep joists from extending too far into the wall, so as not to touch the joists of the adjacent building, which would transmit the flames from one building to the other in case of fire. a good stone sill should be placed under the door, and the floor thereby entirely cut. sills should be raised about one and a half inches above the level of the floor, in order to accomplish the necessary flooding of the same. if stock must be wheeled from one building to the other, the sill can be readily beveled on both sides of the wall, allowing the wheels to pass readily over it. lintels should consist of good brick arches. when swing doors are used, they should be hung on good iron staples, well walled into the masonry, and the staples so arranged that the door will have a tendency to close by its own weight. the door should consist of two layers of good one and a quarter inch boards, nailed crosswise, well nailed together and braced, and then covered with sheet iron nailed on, or if of sheet tin, flanged, soldered, and nailed. particular care should be taken to insert plenty of nails, not only along the edge of the door, but crosswise in all directions. i have seen cases, where the entire covering had been ripped off through the warping tendencies of the sheet iron. the hinges on these doors should be good strap hinges, tightly fastened to the door by bolts extending through it, and secured by nuts on the other side. good latches which keep the door in position when closed should always be provided. in no case should the door be provided with a spring lock which cannot be freely opened, as employes might thereby be confined in a burning room. sliding doors should be hung on wrought iron runways, fastened tightly to the wall. wooden runways iron lined, which we frequently see, are not good, as the charring of the wood in the interior causes them to weaken and the doors to drop. runways should be on an incline, so that the door when not held open will close itself. care must be taken to have a stop provided in the runway, so that the doors may not, as i have frequently seen them, overrun the opening which it is to protect. doors should overlap the edges of the openings on all sides. large projecting jambs should never be used. all doors contained in "fire walls" should have springs or weights attached to them, so as to be at all times closed. fire doors can be shut automatically by a weight, which is released by the melting of a piece of very fusible solder employed for this purpose. so sensitive is this solder that a fire door has been made to shut by holding a lamp some distance beneath the soldered link and holding an open handkerchief between the lamp and link. though the handkerchief was not charred, hot air enough had reached the metal to fuse the solder and allow the apparatus to start into operation. these solders are alloys more fusible than the most fusible of their component metals. a few of them are: wood's alloy, consisting of: cadmium, to parts; tin, parts; lead, parts; bismuth, to parts. this alloy is fusible between ° and ° fahr. the fusible metal of d'arcet is composed of: bismuth, parts; lead, parts; tin, parts. it melts at . °. we can, therefore, by proper mixture, form a solder which will melt at any desirable temperature. numerous devices for closing doors automatically have been constructed, all depending upon the use of the fusible solder catch. * * * * * steel structures. at a recent meeting of the engineers' club of philadelphia, mr. james christie presented a paper upon "the adaptation of steel to structural work." the price of steel has now fallen so low, as compared with iron, that its increased use will be actively stimulated as the building industries revive. the grades and properties of the steels are so distinct and various that opinions differ much as to the adaptability of each grade for a special purpose. hitherto, engineers have favored open hearth steel on account of uniformity, but recent results obtained from bessemer steel tend to place either make on equality. the seeming tendency is to specify what the physical properties shall be, and not how the steel shall be made. for boiler and ship plates, the mildest and most ductile steel is favored. for ships' frames and beams, a harder steel, up to , pounds tenacity, is frequently used. for tension members of bridges, steel of , to , pounds tenacity is usually specified; and for compression members, , to , pounds. in the forth bridge, compression steel is limited to , to , pounds. such a marked advantage occurs from the use of high tension steel in compression members, and the danger of sudden failure of a properly made strut is so little, that future practice will favor the use of hard steel in compression, unless the material should prove untrustworthy. in columns, even as long as forty diameters, steel of , pounds tenacity will exceed the mildest steel per cent., or iron per cent., in compressive resistance. the present uncertainty consists largely as to how high-tension steel will endure the manipulation usual with iron without injury. a few experiments were recently made by the writer on riveted struts of both mild and hard steel, which had been punched, straightened, and riveted, as usual with iron, but no indication of deterioration was found. steel castings are now made entirely trustworthy for tensile working stresses of , to , pounds per square inch. in some portable machinery, an intermittent tensile stress is applied of , pounds, sometimes rising to , pounds per square inch of section, without any evidence of weakness. * * * * * equal volumes of amyl alcohol (rectified fusel oil) and pure concentrated hydrochloric acid, shaken together in a test tube, unite to form a single colorless liquid; if one volume of benzine (from petroleum) be added to this, and the tube well shaken, the contents will soon separate into _three_ distinct colorless fluids, the planes of demarkation being clearly discernible by transmitted light. drop into the tube a particle of "acid magenta;" after again shaking the liquids together, the lower two zones will present different shades of red, while the supernatant hydrocarbon will remain without color. * * * * * a method of measuring the absolute sensitiveness of photographic dry plates. [footnote: from the proceedings of the academy of arts and sciences.--_amer. jour._] by william h. pickering. within the last few years the subject of dry plate photography has increased very rapidly, not only in general popularity, but also in importance in regard to its applications to other departments of science. numerous plate manufacturers have sprung up in this country as well as abroad, and each naturally claims all the good qualities for his own plates. it therefore seemed desirable that some tests should be made which would determine definitely the validity of these claims, and that they should be made in such a manner that other persons using instruments similarly constructed would be able to obtain the same results. perhaps the most important tests needed are in regard to the sensitiveness of the plates. most plate makers use the wet plates as their standard, giving the sensitiveness of the dry plates at from two to sixty times greater; but as wet plates vary quite as much as dry ones, depending on the collodion, condition of the bath, etc., this system is very unsatisfactory. another method, employed largely in england, depends on the use of the warnerke sensitometer. in this instrument the light from a tablet coated with luminous paint just after being exposed to a magnesium light is permitted to shine through a colored transparent film of graduated density upon the plate to be tested. each degree on the film has a number, and, after a given exposure, the last number photographed on the plate represents the sensitiveness on an empirical scale. there are two or three objections to this instrument. in the first place, the light-giving power of the luminous tablet is liable to variations, and, if left in a warm, moist place, it rapidly deteriorates. again, it has been shown by captain abney that plates sensitized by iodides, bromides, and chlorides, which may be equally sensitive to white light, are not equally affected by the light emitted by the paint; the bromides being the most rapidly darkened, the chlorides next, and the iodides least of all. the instrument is therefore applicable only to testing plates sensitized with the same salts. in this investigation it was first shown that the plates most sensitive for one colored light were not necessarily the most so for light of another color. therefore it was evident that the sun must be used as the ultimate source of light, and it was concluded to employ the light reflected from the sky near the zenith as the direct source. but as this would vary in brilliancy from day to day, it was necessary to use some method which would avoid the employment of an absolute standard of light. it is evident that we may escape the use of this troublesome standard, if we can obtain some material which has a perfectly uniform sensitiveness; for we may then state the sensitiveness of our plates in terms of this substance, regardless of the brilliancy of our source. the first material tried was white filter paper, salted and sensitized in a standard solution of silver nitrate. this was afterward replaced by powdered silver chloride, chemically pure, which was found to be much more sensitive than that made from the commercial chemicals. this powder is spread out in a thin layer, in a long paper cell, on a strip of glass. the cell measures one centimeter broad by ten in length. over this is laid a sheet of tissue paper, and above that a narrow strip of black paper, so arranged so as to cover the chloride for its full length and half its breadth. these two pieces of paper are pasted on to the under side of a narrow strip of glass which is placed on top of the paper cell. the apparatus in which the exposures are made consists of a box a little over a meter in length, closed at the top by a board, in which is a circular aperture ' cm. in diameter. over this board may be placed a cover, in the center of which is a hole . cm. in diameter, which therefore lets through . as much light as the full aperture. the silver chloride is placed a distance of just one meter from the larger aperture, and over it is placed the photographic scale, which might be made of tinted gelatines, or, as in the present case, constructed of long strips of tissue paper, of varying widths, and arranged like a flight of steps; so that the light passing through one side of the scale traverses nine strips of paper, while that through the other side traverses only one strip. each strip cuts off about one-sixth of the light passing through it, so that, taking the middle strip as unity, the strips on either side taken in order will transmit approximately-- . . . . . . . . . the instrument is now pointed toward the zenith for about eight minutes, on a day when there is a bright blue sky. on taking the apparatus into the dark room and viewing the impression by gaslight, it will be found that the markings, which are quite clear at one end, have entirely faded out by the time the middle division is reached. the last division clearly marked is noted. five strips cut from sensitized glass plates, ten centimeters long and two and a half in width, are now placed side by side under the scale, in the place of the chloride. by this means we can test, if we wish, five different kinds of plates at once. the cover of the sensitometer containing the . cm. hole is put on, and the plates exposed to sky light for a time varying anywhere between twenty seconds and three minutes, depending on the sensitiveness of the plates. the instrument is then removed to the dark room, and the plates developed by immersing them all at once in a solution consisting of four parts potassium oxalate and one part ferrous sulphate. after ten minutes they are removed, fixed, and dried. their readings are then noted, and compared with those obtained with the silver chloride. the chloride experiment is again performed as soon as the plates have been removed, and the first result confirmed. with some plates it is necessary to make two or three trials before the right exposure can be found; but if the image disappears anywhere between the second and eighth divisions, a satisfactory result may be obtained. the plates were also tested using gaslight instead of daylight. in this case an argand burner was employed burning five cubic feet of gas per hour. a diaphragm cm. in diameter was placed close to the glass chimney, and the chloride was placed at cm. distance, and exposed to the light coming from the brightest part of the flame, for ten hours. this produced an impression as far as the third division of the scale. the plates were exposed in the sensitometer as usual, except that it was found convenient in several cases to use a larger stop, measuring . cm. in diameter. the following table gives the absolute sensitiveness of several of the best known kinds of american and foreign plates, when developed with oxalate, in terms of pure silver chloride taken as a standard. as the numbers would be very large, however, if the chloride were taken as a unit, it was thought better to give them in even hundred thousands. sensitiveness of plates. plates. daylight. gaslight. carbutt transparency . .. allen and rowell . richardson standard . marshall and blair . blair instantaneous . carbutt special . monroe . wratten and wainwright . eastman special . richardson instantaneous . walker reid and inglis . edwards . monckhoven . beebe . cramer . it will be noted that the plates most sensitive to gaslight are by no means necessarily the most sensitive to daylight; in several instances, in fact, the reverse seems to be true. it should be said that the above figures cannot be considered final until each plate has been tested separately with its own developer, as this would undoubtedly have some influence on the final result. meanwhile, two or three interesting investigations naturally suggest themselves; to determine, for instance, the relative actinism of blue sky, haze, and clouds; also, the relative exposures proper to give at different hours of the day, at different seasons of the year, and in different countries. a somewhat prolonged research would indicate what effect the presence of sunspots had on solar radiation--whether it was increased or diminished. * * * * * natural gas fuel and its application to manufacturing purposes. [footnote: read before the iron and steel institute of london, may , .] by mr. andrew carnegie, new york. in these days of depression in manufacturing, the world over, it is specially cheering to be able to dwell upon something of a pleasant character. listen, therefore, while i tell you about the natural gas fuel which we have recently discovered in the pittsburg district. that pittsburg should have been still further favored in the matter of fuel seems rather unfair, for she has long been noted for the cheapest fuel in the world. the actual cost of coal, to such as mine their own, has been between s. and s. per ton; while slack, which has always been very largely used for making gas in siemens furnaces and under boilers, has ranged from s. to s. d. per ton. some mills situated near the mines or upon the rivers for many years received slack coal at a cost not exceeding s. d. per ton. it is this cheap fuel which natural gas has come to supplant. it is now many years since the pumping engines at oil wells were first run by gas, obtained in small quantities from many of the holes which failed to yield oil. in several cases immense gas wells were found near the oil district; but some years elapsed before there occurred to any one the idea of piping it to the nearest manufacturing establishments, which were those about pittsburg. several years ago the product of several gas wells in the butler region was piped to two mills at sharpsburg, five miles from the city of pittsburg, and there used as fuel, but not with such triumphant success as to attract much attention to the experiment. failures of supply, faults in the tubing, and imperfect appliances for use at the mills combined to make the new fuel troublesome. seven years ago a company drilled for oil at murraysville, about eighteen miles from pittsburg. a depth of , feet had been reached when the drills were thrown high in the air, and the derrick broken to pieces and scattered around by a tremendous explosion of gas. the roar of escaping gas was heard in munroville, five miles distant. after four pipes, each two inches in diameter, had been laid from the mouth of the well and the flow directed through them, the gas was ignited, and the whole district for miles round was lighted up. this valuable fuel, although within nine miles of our steel-rail mills at pittsburg, was permitted to waste for five years. it may well be asked why we did not at once secure the property and utilize this fuel; but the business of conducting it to the mills and there using it was not well understood until recently. besides this, the cost of a line was then more than double what it is now; we then estimated that £ , would be required to introduce the new fuel. the cost to-day does not exceed £ , per mile. as our coal was not costing us more than s. per ton of finished rails, the inducement was not in our opinion great enough to justify the expenditure of so much capital and taking the risk of failure of the supply. two years ago men who had more knowledge of the oil-wells than ourselves had sufficient faith in the continuity of the gas supply to offer to furnish us with gas for a sum per year equal to that hitherto annually paid for coal until the amount expended by them on piping had been repaid, and afterward at half that sum. it took us about eighteen months to recoup the gas company, and we are now working under the permanent arrangement of one-half the previous cost of fuel on cars at work. since our success in the use of this new natural fuel at the rail mills, parties still bolder have invested in lines of piping to the city of pittsburg, fifteen to eighteen miles from the wells. the territory underlain with this natural gas has not yet been clearly defined. at the principal field, that of murraysville (from which most of the gas is obtained to-day), i found, upon my visit to that interesting region last autumn, that nine wells had been sunk, and were yielding gas in large quantities. one of these was estimated as yielding , , cubic feet in hours. this district lies to the northeast of pittsburg, running southward from it toward the pennsylvania railroad. gas has been found upon a belt averaging about half a mile in width for a distance of between four and five miles. beyond that again we reach a point where salt water flows into the wells and drowns the gas. several wells have been bored upon this belt near the pennsylvania railroad, and have been found useless from this cause. geologists tell us that in this region a depression of feet occurs in the strata, but how far the fault extends has not yet been ascertained. wells will no doubt soon be sunk southward of the pennsylvania railroad upon this half-mile belt. swinging round toward the southwest, and about twenty miles from the city, we reach the gas fields of washington county. the wells so far struck do not appear to be as strong as those of the murraysville district, but it is possible that wells equally productive may be found there hereafter. there are now four wells yielding gas in the district, and others are being drilled. passing still further to the west, we reach another gas territory, from which manufacturing works in beaver falls and rochester, some twenty-eight miles west of pittsburg, receive their supply. proceeding with the circle we are drawing in imagination around pittsburg, we pass from the west to the southwest without finding gas in any considerable quantity, until we reach the butler gas field, equidistant from pittsburg on the northwest, with washington county wells on the southwest. proceeding now from the butler field to the allegheny river, we reach the tarentum district, still about twenty miles from pittsburg, which is supplying a considerable portion of the gas used. drawing thus a circle around pittsburg, with a radius of fifteen to twenty miles, we find four distinct gas-producing districts. in the city of pittsburg itself several wells have been bored; but the fault before mentioned seems to extend toward the center of the circle, as salt water has rushed in and rendered these wells wholly unproductive, though gas was found in all of them. i spent a few days very pleasantly last autumn driving with some friends to the two principal fields, the murraysville and the washington county. in the former district the gas rushes with such velocity through a -inch pipe, extending perhaps feet above the surface, that it does not ignite within feet of the mouth of the pipe. looking up into the clear blue sky, you see before you a dancing golden fiend, without visible connection with the earth, swayed by the wind into fantastic shapes, and whirling in every direction. as the gas from the well strikes the center of the flame and passes partly through it, the lower part of the mass curls inward, giving rise to the most beautiful effects gathered into graceful folds at the bottom--a veritable pillar of fire. there is not a particle of smoke from it. the gas from the wells at washington was allowed to escape through pipes which lay upon the ground. looking down from the roadside upon the first well we saw in the valley, there appeared to be an immense circus-ring, the verdure having been burnt and the earth baked by the flame. the ring was quite round, as the wind had driven the flame in one direction after another, and the effect of the great golden flame lying prone upon the earth, swaying and swirling with the wind in every direction, was most startling. the great beast apollyon, minus the smoke, seemed to have come forth from his lair again. the cost of piping is now estimated, at the present extremely low prices, with right of way, at £ , sterling per mile, so that the cost of a line to pittsburg may be said to be about £ , sterling. the cost of drilling is about £ , , and the mode of procedure is as follows: a derrick being first erected, a inch wrought-iron pipe is driven down through the soft earth till rock is reached from to feet. large drills, weighing from , to , lb., are now brought into use; these rise and fall with a stroke of to feet. the fuel to run these drills is conveyed by small pipes from adjoining wells. an -inch hole having been bored to a depth of about feet, a - / inch wrought-iron pipe is put down to shut off the water. the hole is then continued inches in diameter until gas is struck, when a -inch pipe is put down. from forty to sixty days are consumed in sinking the well and striking gas. the largest well known is estimated to yield about , , cubic feet of gas in twenty-four hours, but half of this may be considered as the product of a good well. the pressure of gas as it issues from the mouth of the well is nearly or quite lb. per square inch. one of the gauges which i examined showed a pressure of lb. even at works where we use the gas nine miles from the well, the pressure is lb. per square inch. at one of the wells, where it was desirable to have a supply of pure water, i found a small engine worked by the direct pressure of the gas as it came from the well; and an excellent supply of water was thus obtained from a spring in the valley. eleven lines of pipe now convey gas from the various wells to the manufacturing establishments in and around pittsburg. the largest of these for the latter part of the distance is inches in diameter. several are of inches throughout. the lines originally laid are inches in diameter. many of the mills have as yet no appliances for using the gas, and much of it is still wasted. it is estimated that the iron and steel mills of the city proper require fuel equal to , bushels of coal per day; and though it is only two years since gas was first used in pittsburg, it has already displaced about , bushels of coal per day in these mills. sixty odd glass works, which required about , bushels of coal per day, mostly now use the natural gas. in the work around pittsburg beyond the city limits, the amount of coal superseded by gas is about equal to that displaced in the city. the estimated number of men whose labor will be dispensed with in pittsburg when gas is generally used is , . it is only a question of a few months when all the manufacturing carried on in the district will be operated with the new fuel. as will be seen from the analyses appended to this paper, it is a much purer fuel than coal; and this is a quality which has proved of great advantage in the manufacture of steel, glass, and several other products. with the exception of one, and perhaps two concerns, no effort has been made to economize in the use of the new fuel. in our union iron mills we have attached to each puddling furnace a small regenerative appliance, by the aid of which we save a large percentage of fuel. the gas companies will no doubt soon require manufacturers to adopt some such appliance. at present, owing to the fact that there is a large surplus constantly going to waste, they allow the gas to be used to any extent desired. contracts are now made to supply houses with gas for all purposes at a cost equal to that of the coal bill for the preceding year. in the residences of several of our partners no fuel other than this gas is now used, and everybody who has applied it to domestic purposes is delighted with the change from the smoky and dirty bituminous coal. some, indeed, go so far as to say that if the gas were three times as costly as the old fuel, they could not be induced to go back to the latter. it is therefore quite within the region of probability that the city, now so black that even sheffield must be considered clean in comparison, may be so revolutionized as to be the cleanest manufacturing center in the world. a walk through our rolling mills would surprise the members of the institute. in the steel rail mills for instance, where before would have been seen thirty stokers stripped to the waist, firing boilers which require a supply of about tons of coal in twenty-four hours--ninety firemen in all being employed, each working eight hours--they would now find one man walking around the boiler house, simply watching the water gauges, etc. not a particle of smoke would be seen. in the iron mills the puddlers have whitewashed the coal bunkers belonging to their furnaces. i need not here say how much pleasure it will afford me to arrange that any fellow members of the institute who may visit the republic are afforded an opportunity to see for themselves this latest and most interesting development of the fuel question. good mother earth supplies us with all the fuel we can use and more, and only asks us to lead it under our boilers and into our heating and puddling furnaces, and apply the match. during the winter several explosions have occurred in pittsburg, owing to the escape of gas from pipes improperly laid. the frost having penetrated the earth for several feet and prevented escape upward, the freed gas found its way into the cellars of houses, and, as it is odorless, its presence was not detected. this resulted in several alarming explosions; but the danger is to be remedied before next year. lower pressure will be carried in the pipes through the city, and escape pipes leading to the surface will be placed along the surface at frequent intervals. in the case of manufacturing establishments, the gas is led into the mills overhead, and, all the pipes being in the open air, no danger of explosion is incurred. the following extract from the report of a committee, made to the american society of mechanical engineers at a recent meeting, gives an idea of the value of the new fuel: "natural gas, next to hydrogen, is the most powerful of the gaseous fuels, and, if properly applied, one of the most economical, as very nearly its theoretical heating power can be utilized in evaporating water. being so free from all deleterious elements, notably sulphur, it makes better iron, steel, and glass than coal fuel. it makes steam more regularly, as there is no opening of doors, and no blank spaces are left on the grate bars to let cold air in, and, when properly arranged, regulates the steam pressure, leaving the man in charge nothing to do but to look after the water, and even that could be accomplished if one cared to trust to such a volatile water-tender. boilers will last longer, and there will be fewer explosions from unequal expansion and contraction, due from cold draughts of air being let in on hot plates. "an experiment was made to ascertain the value of gas as a fuel in comparison with coal in generating steam, using a retort or boiler of inches diameter, feet long, with inch tubes. it was first fired with selected youghiogheny coal, broken to about inch cubes, and the furnace was charged in a manner to obtain the best results possible with the stack that was attached to the boiler. nine pounds of water evaporated to the pound of coal consumed was the best result obtained. the water was measured by two meters, one in the suction and the other in the discharge. the water was fed into a heater at a temperature of from ° to °; the heater was placed in the flue leading from the boiler to the stack in both gas and coal experiments. in making the calculations, the standard lb. bushel of the pittsburg district was used. six hundred and eighty-four pounds of water were evaporated per bushel, which was . per cent. of the theoretical value of the coal. where gas was burned under the same boiler, but with a different furnace, and taking lb. of gas to be . cubic feet, the water evaporated was found to be . lb., or . per cent. of the theoretical heat units were utilized. the steam was under the atmospheric pressure, there being a large enough opening to prevent any back pressure, the combustion of both gas and coal was not hurried. it was found that the lower row of tubes could be plugged and the same amount of water could be evaporated with the coal; but with gas, by closing all the tubes--on the end next the stack--except enough to get rid of the products of combustion, when the pressure on the walls of the furnace was three ounces, and the fire forced to its best, it was found that very nearly the same results could be obtained. hence it was concluded that the most of the work was done on the shell of the boiler." in no other way can i give the members of the iron and steel institute so much information in regard to this new fuel as by including in this paper a very able communication from the chief chemist at our edgar thomson steel works, mr. s.a. ford, who is to-day the highest authority upon the subject: "so much has been claimed for natural gas as regards the superiority of its heating properties as compared with coal, that some analyses of this gas, together with calculations showing the comparison between its heating power and that of coal, may be of interest. these calculations are, of course, theoretical in both cases, and it must not be imagined that the total amount of heat, either in a ton of coal or , cubic feet of natural gas, can ever be fully utilized. in making these calculations i employed as a basis what in my estimation was a gas of an average chemical composition, as i have found that gas from the same well varies continually in its composition. thus, samples of gas from the same well, but taken on different days, vary in nitrogen from per cent. to _nil_, carbonic acid from per cent. to _nil_, oxygen from per cent, to . per cent., and so with all the component gases. before giving the theoretical heating power of , cubic feet of this gas i will note a few analyses. the first four are of gas from the same well; samples taken on the same day that they were analyzed. the two last are from two different wells in the east liberty district: analyses of natural gas. --------------------+--------+--------+--------+--------+--------+--------+ | | | | | | | --------------------+--------+--------+--------+--------+--------+--------+ when tested.........| - - | - - | - - | - - | - - | - - | | per ct.| per ct.| per ct.| per ct.| per ct.| per ct.| carbonic acid ......| . | . | nil. | . | nil. | . | carbonic oxide......| . | . | . | . | . | . | oxygen... ... ......| . | . | . | . | . | . | olefiant gas .......| . | . | . | . | . | . | ethylic hydride ....| . | . | . | . | . | . | marsh gas ..........| . | . | . | . | . | . | hydrogen ...........| . | . | . | . | . | . | nitrogen ...........| nil. | nil. | nil. | nil. | . | . | heat units .........| , | , | , | , | , | , | --------------------+--------+--------+--------+--------+--------+--------+ "we will now show how the natural gas compares with coal, weight for weight, or, in other words, how many cubic feet of natural gas contain as many heat units as a given weight of coal, say a ton. in order to accomplish this end we will be obliged, as i have said before, to assume as a basis for our calculations what i consider a gas of an average chemical composition, viz.: per cent. carbonic acid............................ . carbonic oxide........................... . oxygen................................... . olefiant gas............................. . ethylic hydride.......................... . marsh gas............................... . hydrogen................................ . nitrogen................................. . "now, by the specific gravity of these gases we find that liters of this gas will weigh . grammes, thus: weight, liters. grammes. marsh gas................. . . olefiant gas.............. . . ethylic hydride........... . . hydrogen.................. . . nitrogen.................. . . carbonic acid............. . . carbonic oxide............ . . oxygen.................... . . ------- total................................... . "then, if we take the heat units of these gases, we will find: heat units grammes. contained. marsh gas................ . , olefiant gas............. . , ethylic hydride.......... . , hydrogen................. . , carbonic oxide........... . , nitrogen................. . ----- carbonic acid............ . ----- oxygen................... . ----- ------- ------- totals . , " . grammes are almost exactly , grains, and cubic foot of this gas will weigh . grains; then the liters, or . grammes, or , grains, are , cubic feet; , cubic feet of this gas contains , heat units, and , cubic feet will contain , , heat units. now, , cubic feet of this gas will weigh , grains, or in round numbers lb. avoirdupois. we find that . grammes, or , grains, of carbon contain , heat units, and , grains, or lb., of carbon contain , , heat units. then . lb. of carbon contain the same number of heat units as , cubic feet of the natural gas, viz., , , . now, if we say that coke contains in round numbers per cent. carbon, then we will have . lb. of coke, equal in heat units to , cubic feet of natural gas. then, if a ton of coke, or , lb., cost s., . lb. will cost d., or , cubic feet of gas is worth d. for its heating power. we will now compare the heating power of this gas with bituminous coal, taking as a basis a coal slightly above the general average of the pittsburg coal, viz.: per cent. carbon................................... . hydrogen................................. . nitrogen................................. . oxygen................................... . ash...................................... . sulphur.................................. . "we find that lb. of this coal contains , , heat units. the . lb. of this coal contains , , heat units, or . lb. of coal is equal in its heating power to , cubic feet of natural gas. if our coal cost us s. per ton of , lb., then . lb. costs . d., and , cubic feet of gas is worth for its heat units . d. as the price of coal increases or decreases, the value of the gas will naturally vary in like proportions. thus, with the price of coal at s. per ton the gas will be worth . d. per , cubic feet. if . lb. of coal is equal to , cubic feet of gas, then one ton, or , lb., is equal to , cubic feet, or , lb. of coal is equal to , cubic feet of natural gas. if we compare this gas with anthracite coal, we find that , cubic feet of gas is equal to . lb. of this coal, and , lb. of coal is equal to , cubic feet of natural gas. then, if this coal cost s. per ton, , cubic feet of natural gas is worth ½d. for its heating power. in collecting samples of this gas i have noticed some very interesting deposits from the wells. thus, in one well the pipe was nearly filled up with a soft grayish-white material, which proved on testing to be chloride of calcium. in another well, soon after the gas vein had been struck, crystals of carbonate of ammonia were thrown out, and upon testing the gas i found a considerable amount of that alkali, and with this well no chloride of calcium was observed until about two months after the gas had been struck. in these calculations of the heating power of gas and coal no account is of course taken of the loss of heat by radiation, etc. my object has been to compare these two fuels merely as regards their actual value in heat units." bearing in mind that it is never wise to prophesy unless you know, i hesitate to speak of the future; but considering the experience we have had in regard to the productiveness of the oil territory, which is now yielding , barrels of petroleum per day, and which has continued to increase year after year for twenty years, i see no reason to doubt the opinion of experts that the territory which has already been proved to yield gas will suffice for at least the present generation in and about pittsburg. * * * * * a gas-engine water-supply alarm. [illustration] a very useful contrivance for the purpose of reporting automatically the failure of the water supply to a gas-engine has been arranged by professor ph. carl, of munich. what led to the adoption of the device was that, during last winter, the water supply in the neighborhood of the professor's laboratory was several times cut off without previous notice; the result being the failure of the water needed for cooling the cylinder of his otto gas-engine. on inquiring into the matter, he discovered that the same thing frequently occurred in other places where gas-engines were in use; and this caused him to design a contrivance to put an alarm-bell into action at the instant when the water ceased to flow, and so enable any overheating of the engine, and injuries thereby resulting, to be prevented in time. the arrangement (represented half size in the accompanying engraving) is screwed down directly to the water outflow pipe, r. before the aperture of the pipe is a lever, with a disk on one arm, on to which the issuing water impinges, thereby keeping the lever in the position indicated by the dotted lines. the effect of this is to break the platinum contact at c, and so interrupt the circuit of an alarm-bell placed in any suitable position. suppose the water ceases to flow; the spring, f, comes into play, contact is made at c, and the bell continues to ring till some one comes to stop it. it is almost needless to remark that the disk, d, and the pin, e, are composed of insulating material, such as vulcanite.--_jour. gas lighting._ * * * * * soldering and repairing platinum vessels in the laboratory. by j.w. pratt, f.c.s. it frequently happens in the laboratory that platinum vessels, after long-continued use, begin to show signs of wear, and become perforated with minute pinholes. when they have reached this stage, they are usually accounted of no further utility, and are disposed of as scrap; not that it is impossible to repair them--for with fine gold wire and an oxyhydrogen jet this is easily feasible--but that the proper appliances and skill are not in possession of all. irrespective of the manipulation of the hydrogen jet, it is rather difficult without long practice to hold the end of the fine wire precisely over the aperture and to keep it in position. it occurred to me that, if the gold in a finely divided condition could be placed in very intimate contact with the platinum, judging from the fusibility of gold-platinum alloys, union could be effected at a lower temperature over the ordinary gas blowpipe. i tried the experiment, and found the supposition correct. the substance i used was auric chloride, aucl_{ }, which, as is well known, splits up on heating, first into aurous chloride, and at a higher temperature gives off all its chlorine and leaves metallic gold. operating on a perforated platinum basin, in the first instance, i placed a few milligrammes of the aurous chloride from a grain tube precisely over the perforation, and then gently heated to about ° c. till the salt melted and ran through the holes. a little further heating caused the reduced gold to solidify on each side of the basin. the blowpipe was now brought to bear on the bottom of the dish, right over the particular spots it was wished to solder, and in a few moments, at a yellow-red heat (in daylight), the gold was seen to "run." on the vessel being immediately withdrawn, a very neat soldering was evident. the operation was repeated several times, till in a few minutes the dish had been rendered quite tight and serviceable. using the gold salt in this way, the principal difficulty experienced in holding gold wire unflinchingly in the exact position vanishes, while only a comparatively low temperature and small amount of gold is necessary. care must be taken to withdraw the platinum from the flame just at the moment the gold is seen to run, for if the heat be continued longer, the gold alloys with a larger surface of platinum, spreads, and leaves the aperture empty. as in the case of all gold-soldered vessels, the article cannot afterward be safely exposed to a temperature higher than that at which the soldering was effected, and on this account it is advisable to use as small an amount of auric chloride as possible. when the perforations are of comparatively large size, the repairing is not so easy, owing to the auric chloride, on fusing, refusing to fill them. i find, however, that if some spongy platinum be mixed with a few milligrammes of the gold salt, pressed into the perforation, and heat applied as directed, a very good soldering can be effected. it is well to hammer the surface of the platinum while hot, so as to secure perfect union and welding of the two surfaces. this may be done in a few minutes in such a manner as to render the repair indistinguishable. strips of platinum may be joined together in much the same way as already described--a few crystals of auric chloride placed on each clean surface and gently heated till nearly black, then bound together and further heated for a few moments in the blowpipe flame. rings and tubes can also be formed on a mandrel, and soldered in the same fashion, and the chemist thus enabled to build up small pieces of apparatus from sheet platinum in the laboratory.--_chem. news._ * * * * * the helicoidal or wire stone saw. the sides of solid bodies, whatever be the degree of hardness, and however fine the texture, possess surfaces formed of a succession of projections and depressions. when two bodies are in contact, these projections and indentations fit into one another, and the adherence that results is proportional to the degree of roughness of the surfaces. if, by a more or less energetic mechanical action, we move one of the bodies with respect to the other, we shall produce, according as the action overcomes cohesion, more or less disintegration of the bodies. the resulting wear in each of them will evidently be inversely proportional to its hardness and the nature of its surface; and it will vary, besides, with the pressure exerted between the surfaces and the velocity of the mechanical action. we may say, then, that the wear resulting from rubbing two bodies against each other is a function of their degree of hardness, of the extent and state of their surface, of the pressure, of the velocity, and of the time. [illustration: figs. , and .--apparatus for sawing stone.] according as these factors are varied in a sense favorable or unfavorable to their proper action, we obtain variations in the final erosion. thus, in rubbing together two bodies of different hardness and nature of surface, we obtain a wear inversely proportional to the hardness and state of polish of their surfaces. through the interposition of a pulverized hard body we can still further accelerate such wear, as a consequence of the rapid renewal of the disintegrating element. the gradual wear effected over the entire surface of a body brings about a polish, while that effected along a line or at some one point determines a cleavage or an aperture. the process usually employed in quarries or stone-yards for sawing consists in slowly moving a stone-saw backward and forward, either by hand or machinery, and with scarcely any pressure. mr. p. gray has, however, devised a new process, which is based upon the theoretical considerations given above. his _helicoidal saw_ is, in reality, an endless cable formed by twisting together three steel wires in such a way as to give the spirals quite an elongated pitch. the apparatus in its form for cutting blocks of stone into large slabs (figs. , , and ) consists of two frames, a a, five feet apart, each formed of two iron columns, ½ feet in height and one foot apart, fixed to cast iron bases resting upon masonry. at the upper part, a frame, b b, formed of double t-irons cross-braced here and there, supports a transmission composed of gearwheels, r r, and a pitch-chain, g g. along the columns of the frame, which serve as guides, move two kinds of pulley-carriers, c c. the pulleys, d d, are channeled, and receive the cable, a a, which serves as a helicoidal saw. the direction of the saw's motion is indicated by the arrow. the carriages, c c, are traversed by screws, v v, which are fixed between the columns. the extremity, v, of the axle of the pulley to the right is threaded, and actuates a helicoidal wheel, e, which transmits motion to the wheel, r, through the intermedium of the vertical shaft, f. this transmission, completed by the wheels, r r, and the pitch-chains, g g, is designed to move the saw vertically, through the simultaneous shifting of the carriages, c c. a tension weight, p, through the intermedium of pulleys, d_{ } d_{ }, permits of keeping the saw taut. a reservoir, h, at the upper part of the frame, b b, contains the water and sand necessary for sawing. the feeding is effected by means of a rubber tube, i, terminating in a flattened rose, j, which is situated over the aperture made by the saw. a small pump, l. over the reservoir takes water from k, and raises it to h. the sand is put in by hand. above the basin, k, a system of rails and ties supports the carriage, q, upon which is placed the block of stone to be sawn. when one operation has been finished, and it is desired to begin another, it is necessary to raise the pulley-carriers and the saw. in order to do this quickly, there is provided a special transmission, m, which is actuated by hand, through a winch. the work done by this saw is effected more rapidly than by the ordinary processes, and certain very hard rocks, usually regarded as almost intractable, can be sawed at the rate of from one to one and a half inches per hour. [illustration: fig. .--apparatus for sawing stone into slabs.] for sawing marble into slabs of all thicknesses, the arrangement described above may be replaced by a system consisting of two drums having several channels to receive as many saws, or two corresponding series of channeled pulleys, b b (fig. ), independent of each other, but keyed to the same axles, i i. when the pulleys have been properly spaced by means of keys, the whole affair is rendered solid by a bolt, g. the extremity of the axles forms a nut into which pass vertical screws, c c. these latter are connected above with cone-wheels, l l, which, gearing with bevel wheels keyed to the shafts, e, secure a complete interdependence of the whole. the ascending motion, which is controlled by the endless screws, f, and the helicoidal wheels, m, is in this way effected with great regularity. uprights, a a, of double t-iron, fixed to joists, k k, and connected and braced by pieces, d d, form a strong frame. [illustration: fig. .--application of gay's stone saw in a marble quarry.] the power necessary to run this kind of saw is less than _n_ × ¼ h.p., on account of the number of passive parts. the most interesting application of the helicoidal saw is in the exploitation of quarries. fig. represents a belgian marble quarry which is being worked by mr. gay's method. _tubular perforators_.--mr. gay has rendered his saw completer by the invention of a tubular perforator for drilling the preliminary well. it is based upon the same principle as the leschot rotary drill, but differs from that in its extremity being simply of tempered steel instead of being set with black diamonds. a special product, called metallic agglomerate, is used instead of sand for hastening the work. [illustration: fig. .--tubular perforator.] the apparatus, fig. , consists of an iron plate cylinder, a, ½ inches in diameter, and of variable length, according to the depth to be obtained, and terminating beneath in a steel head, b, of greater thickness. this cylinder is traversed by a shaft, c, to which it is keyed, and which passes through the center of the aperture drilled. this shaft is connected with the cylinder, a, through the intermedium of cross bars, d, and transmits thereto a rapid rotary motion, which is received at the upper part from a telodynamic wire that passes through the channel of the horizontal pulley, p. this latter is supported by a frame consisting of three uprights, q q, strengthened by stays, r r, fixed to the ground. in order that the cylinder, a, may be given a vertical motion, cords, m m, fixed to a piece, s, loose on the hub, d, wind round the drum of a windlass, t, after passing over the pulleys, p p. the rapid gyratory motion of the cylinder, along with the erosive action of the metallic agglomerate, rapidly wears away the rock, and causes the descent of the perforator. during this operation a core of marble forms in the cylinder. this is detached by lateral pressure, and is capable of being utilized. the tool descends at the rate of from to inches per hour, or from to yards per day in ordinary lime rock.--_le genie civil_. * * * * * portable prospecting drill. [illustration: portable prospecting drill.] the aqueous works and diamond rock-boring company, limited, of london, show at the inventions exhibition, london, a light portable rock-boring machine for prospecting for minerals, water, etc. it is capable of sinking holes from in. to in. in diameter, and to a depth of ft. the screwed boring spindle, which is in front of the machine, is actuated by miter gearing driven by a six horse power engine; the speed of driving is revolutions a minute. the pump shown on the left-hand side of the engraving is used to deliver a constant stream of water through the boring bar, the connection being made by a flexible hose. suitable winding gear for raising or lowering the lining tubes, boring rods, etc., is also mounted on the same frame. the drill is automatic in its action, and the speed can be regulated by friction gearing. the front part of the carriage is arranged so that it can be swung clear of the drill to raise and lower the bore rods, etc. * * * * * automatic safety gear. among the safety appliances which are to be found in the mining section of the inventions exhibition is a model of an ingenious contrivance for the prevention of overwinding, the joint patent of mr. w.t. lewis, aberdare, lead mineral agent to the marquis of bute, and w.h. massey, electric light engineer to the queen. both these gentlemen, having been members of jury, were not allowed to compete for an award. the invention, says _engineering_, seems to possess considerable merit, and it should prove of practical utility in collieries where enginemen are usually kept winding for many hours at a stretch, and where the slightest mistake on the part of the driver may lead to an accident. safety hooks are often fitted to winding ropes, and although the damage to life and property is greatly reduced by the use of them, they do not protect a descending cage from injury in a case of overwinding; besides which, they are almost useless when a wild run takes place, an accident which, strange to say, has already occurred many times after engines and boilers have been laid off for repairs. stop valves are left open, the reversing lever is not fixed in mid-gear, steam is got up in the boilers at a time when no one is in the engine house, and the engines run away. [illustration: lewis & massey's automatic safety gear.] various devices have been suggested and tried as a preventive, but their application has either caused as much mischief as a bad accident, or it has depended upon the driver doing something intentionally; whereas in the automatic gear of messrs. massey and lewis, of which an illustration is annexed, there is nothing to cause damage or to interfere in any way with the proper handling of the engines, and it is practically out of the power of the driver to render the gear inoperative. it is here shown in its simplest form as applied to the ordinary reversing and steam handles of a winding engine, the only additions being an arm jointed to the top of the valve spindle, with its connections to the shaft of the reversing lever, and a disk receiving a suitable motion from the main shaft of the engine. on the disk is a projecting piece or stop which is brought into such positions, at or near the end of each journey, that the stop valve cannot be opened, except slightly, when the reversing lever is not set for winding in the proper direction, or when the cages have reached a point beyond which it is undesirable that the engine driver should have the power of turning on full steam. thus, if one cage is at bank, the driver cannot draw it up into the head gear suddenly; but after it has been lifted slowly off the keeps or fangs, and the reversing lever thrown over, the stop valve can be lifted wide open; and supposing that while the engine is running the driver neglects to shut off steam in proper time, then the projecting piece on the disk in traveling round, slowly or quickly, and by steps according to requirements, will come in contact with the driver, and so prevent an accident by bringing the reversing lever into or beyond mid-gear. messrs. lewis and massey contemplate the use of governors in combination with various forms of their automatic gear, so as to provide for every imaginable case of winding, and also to avoid accidents when heavy loads are sent down a pit; the special feature in their mechanism being that when two or more things happen with regard to the positions of steam or reversing handles, speed or position of cages in the pit, whatever it may be necessary to do to meet the particular case shall be done automatically. * * * * * the water supply of ancient roman cities. [footnote: an address by prof. w.h. corfield, m.d., m.a., delivered before the sanitary institute of great britain, july , .--_building news_.] as the supply of water to large populations is one of the most important subjects in connection with sanitary matters, and one upon which the health of the populations to a very large extent depends, i propose to give a short account of some of the more important works carried out for this purpose by the ancient romans--the great sanitary engineers of antiquity--more especially as i have had exceptional opportunities of examining many of those great works in italy, in france, and along the north coast of africa. of the aqueducts constructed for the supply of rome itself we have an excellent detailed account in the work of frontinus, who was the controller of the aqueducts under the emperor nerva, and who wrote his admirable work on them about a.d. . it may be interesting in passing to mention that frontinus was a patrician, who had commanded with distinction in britain under the emperor vespasian, before he was appointed by the emperor nerva as controller (or, we should say, surveyor) of the aqueducts. he was also an antiquarian, and in his work he not only describes the aqueducts as they were in this time, but also gives a very interesting history of them. he begins by telling us that for years after the building of the city--that is to say, b.c. --there was no systematic supply of water to the city; that the water was got direct from the tiber, from shallow wells, and from natural springs; but that these sources were found no longer to be sufficient, and the construction of the first aqueduct was undertaken during the consulship of appius claudius crassus, from whom it took the name of the appian aqueduct. this was, as may be expected from its being the first aqueduct, not a very long one; the source was about eight miles to the east of rome, and the length of the aqueduct itself rather more than eleven miles, according to mr. james parker, to whose paper on the "water supply of ancient rome" i am indebted for many of the facts concerning the aqueducts of rome itself. this aqueduct was carried underground throughout its whole length, winding round the heads of the valleys in its course, and not crossing them, supported on arches, after the manner of more recent constructions; it was thus invisible until it got inside the city itself, a very important matter when we consider how liable rome was, in these early times, to hostile attacks. it was soon found that more water was required than was brought by this aqueduct, and it was no doubt considered desirable to have tanks at a higher level in the city than those supplied by the appian aqueduct. it was determined, therefore, to bring water from a greater height, and from a greater distance, and the river anio, above the falls at tivoli, was selected for this purpose. the second aqueduct, the anio vetus, was no less than miles in length, and was, like the appian, entirely under the surface of the ground, except at its entrance into rome at a point about ft. higher than the level of the appian aqueduct. little search has been made for the remains of this aqueduct, and its exact course is not known; but during my examination of the remains of the subsequent aqueducts at a place called the porta furba, near rome, where the ruins of five aqueducts are seen together, and at, or close to, which point the anio vetus must also have passed underground, i was rewarded for my search by discovering a hole, something like a fox's hole, leading into the ground; and on clearing away a few loose stones which had apparently been thrown into it, and putting my arm in, i found that it led into the specus or channel of an underground aqueduct; and on relating this incident to the late mr. john henry parker, the antiquarian, who was then in rome, and showing him a sketch of the place, he said that he had no doubt that i had been fortunate enough to discover the exact position of the veritable anio vetus at that spot. these two aqueducts sufficed for the supply of rome with water for about years, for frontinus tells us that years after the date at which the construction of the anio vetus was undertaken--that is to say, the th year after the foundation of the city--the increase of the city necessitated a more ample supply of water, and it was determined to bring it from a still greater distance. it was no longer considered necessary to conceal the aqueduct underground during the whole of its course, and so it was in part carried above ground on embankments or supported upon arches of masonry. the water was brought from some pools in one of the valleys on the eastern side of the anio, some miles farther up than the point from which the anio vetus was supplied; and the new aqueduct, which was miles in length, was called the marcian, after the prætor marcius, to whom the work was intrusted. frontinus also tells us the history of the other six aqueducts which were in existence in his time, viz., the tepulan, the julian, the virgo, the alsietine or augustan, the claudian, and the anio novus; the last two being commenced by the emperor caligula, and finished by claudius, because "seven aqueducts seemed scarcely sufficient for public purposes and private amusements;" but it is not necessary for our purpose to give any detailed account of the course of these aqueducts; it is only necessary to mention one or two very interesting points in connection with them. in order to allow of the deposit of suspended matters, piscinæ, or settling reservoirs, were constructed in a very ingenious manner. each had four compartments, two upper and two lower; the water was conducted into one of the upper compartments, and from this passed, probably by what we should call a standing waste or overflow pipe, into the one below; from this it passed (probably through a grating) into the third compartment at the same level, and thence rose through a hole in the roof of this compartment into the fourth, which was above it, and in which the water, of course, attained the same level as in the first compartment, thence passing on along the aqueduct, having deposited a good deal of its suspended matter in the two lower compartments of the piscinæ. arrangements were made by which these two lower compartments should be cleaned out from time to time. the specus or channel itself was, of course, constructed of masonry, generally of blocks of stone cemented together, and it was frequently, though not, it would appear always, lined with cement inside. it was roofed over, and ventilating shafts were constructed at intervals; in order to encourage the aeration of the water, irregularities were occasionally introduced in the bed of the channel. the water supplied by the different aqueducts was of various qualities; thus, for instance, that of the alsietine, which was taken from a lake about miles from rome, was of an inferior quality, and was chiefly used to supply a large naumachia, or reservoir, in which imitation sea fights were performed; while, on the other hand, the water of the marcian was very clear and good, and was therefore used for domestic purposes. frontinus gives the most accurate details as to the measurements of the amount of water supplied by the various aqueducts, and the quantities used for different purposes. from these details mr. parker computes the sectional area of the water at about square feet, and says: "we can form some opinion of the vast quantity if we picture to ourselves a stream ft. wide by ft. deep constantly pouring into rome at a fall six times as rapid as that of the river thames." he considers that the amount was equivalent to about million gallons a day, or gallons per head per day, assuming the population of the city to be a million. when we consider that we in london have only gallons a head daily, and that many other towns have less, we get some idea of the profusion with which water was supplied to ancient rome. but the remains of roman aqueducts are not only to be found near rome. almost every roman city, whether in italy or in the south of france, or along the north coast of africa, can show the remains of its aqueduct, and almost the only things that are to be seen on the site of carthage are the remains of the roman water tanks and the ruins of the aqueduct which supplied them. the most beautiful aqueduct bridge in the world, on the course of the aqueduct which supplied the ancient nemaucus, now nismes, still stands, and is called, from the name of the department in which it is, the pont du gard. it consists of a row of large arches crossing the valley over which the water had to be carried, surmounted by a series of smaller arches, and these again by a series of still smaller ones, carrying the specus of the aqueduct. this splendid bridge still stands perfect, so that one can walk through the channel along which the water flowed, and it might be again used for its original purpose. there was, however, one city which, from the fact that a great part of it was situated upon a hill, was more difficult to supply with water than any of the rest, and which, at the same time, from its size, its great importance, and the fact that it was the favorite summer residence of several of the roman emperors, and notably of claudius, who was born there, and who had a palace on the top of the hill, must of necessity be supplied with plenty of water, and that too from a considerable height. i refer to ludgunum (now lyons), then the capital of southern gaul. this city was built by lucius munatius plaucus, by order of the senate in a.u.c. . augustus went there in a.u.c. , and afterward lived there from to . it was he who raised it to a very high rank among roman cities. it had its forum near the top of the hill now called fourvieres (probably a corruption of forum vetus), an imperial place on the summit of the same hill, public baths, an amphitheater, a circus, and temples. in order to supply this city with water, standing as it did on the side of a hill at the junction of two great rivers (now rhone and saone), it was necessary to search for a source at a sufficient height, and this plaucus found in the hills of mont d'or, near lyons, where a plentiful supply of water was found at a sufficient height, viz., that of nearly , ft. above the sea. from this point an aqueduct, sometimes called from its source the aqueduct of mont d'or, and sometimes the aqueduct of ecully, from the name of a large plain which it crossed, was constructed, or rather two subterranean aqueducts were made and joined together into one, which crossed the plain of ecully, in a straight line still underground; but the ground around lyons was not like the campagna, near rome, and it was necessary to cross the broad and deep valley now called la grange, blanche. this, however, did not daunt the roman engineers; making the aqueduct end in a reservoir on one side of the valley, they carried the water down into the valley, probably by means of lead pipes, in the manner which will be described more at length further on, across the stream at the bottom of the valley by means of an aqueduct bridge ft. long, ft. high, and ½ ft. broad, and up the other side into another reservoir, from which the aqueduct was continued along the top of a long series of arches to the reservoir in the city, after a course of about ten miles. in the time of augustus, however, it was found that the water brought by this aqueduct was not sufficient, especially in summer; and as there was a large roman camp which also required to be supplied with water, situated at a short distance from the city, it was determined to construct a second aqueduct. for this purpose the springs at the head of a small river, called now the brevenne, were tapped, and conveyed by means of an underground aqueduct (known as the aqueduct of the brevenne) which wound round the heads of the valleys, and after a course of about thirty miles is believed by some to have arrived at the city, but by others to have stopped at the roman camp, and to have been constructed exclusively for its supply. i have here a diagram, after flacheron, showing a section of this aqueduct, and this will give a very good general idea of the section of a roman aqueduct where constructed underground. it will be seen that the specus or channel is centimeters (or nearly ft.) wide, and m. c. (or a little over ft.) high, and that it is lined with a layer of c. (or nearly ¼ in.) of cement. it is constructed of quadrangular blocks of stone cemented together, and has an arched stone roof. it will be noticed also that the angles at the lower part of the channel are filled up with cement; it appears also that this aqueduct crossed a small valley by means of inverted siphons. but neither of these aqueducts came from a source sufficiently high to supply the imperial palace on the top of fourvieres. their sources are, in fact, according to flacheron, at a height of nearly ft. below the summit of fourvieres, and it was, therefore, considered necessary by the emperor claudius to construct a third aqueduct. the sources of the stream now called the gier, at the foot of mont pila, about a mile and a half above st. chamond, were chosen for this purpose, and from this point to the summit of fourvieres was constructed by far the most remarkable aqueduct of ancient times, an engineering work which, as will be seen from the following description, partly taken from montfalcon's history of lyons, partly from flacheron's account of this aqueduct, and partly from my own observations on the spot, reflects the greatest possible credit on the roman engineers, and shows that they were not, as has been frequently supposed by those who have only examined aqueducts at rome, by any means ignorant of the elementary principles of hydraulics. to tap the sources of a river at a point over miles from the city, and to bring the water across a most irregular country, crossing ten or twelve valleys, one being over ft. deep, and about two-thirds of a mile in width, was no easy task; but that it was performed the remains of the aqueduct at various parts of its course show clearly enough. it commences, as i have said, about a mile and a half from the present st. chamond, a town on the river gier, about miles from st. etienne. here a dam appears to have been constructed across the bed of the river, forming a lake from which the water entered the channel of the aqueduct, which passed along underground until it came to a small stream which it crossed by a bridge, long since destroyed. after this it again became subterraneous for a time, and then crossed another stream on a bridge of nine arches, the ruins of some of the columns of which are still to be seen; and from these ruins it would appear that the bridge had, at some time or another, been destroyed, probably by the stream running under it having become torrential, and subsequently rebuilt; again it became concealed underground, to reappear in crossing a small valley and another small stream, when it was again concealed by the ground, and in one or two places channels were even cut for it through the solid rock, after which it reappeared on the surface at a point where now stands the village of terre-noire, and where it was necessary that it should somehow or another cross a broad and deep valley. it ended in a stone reservoir, from which eight lead pipes descending into the valley were carried across the stream at the bottom on an aqueduct bridge, about ft. wide, and supported by twelve or thirteen arches, and then mounted the other side of the valley into another reservoir, of which scarcely any remains are now seen, from which the aqueduct started again, disappearing almost immediately under the surface of the ground, to appear again from time to time crossing similar valleys and streams upon bridges, the remains of some of which may still be seen, until it reached soucieu, on the edge of the valley of the garonne, where are still seen the remains of a splendid bridge, the thirteenth on its course, nearly , ft. long, and attaining a height of ft. at its highest point above the ground. the object of this bridge was to convey the channel of the aqueduct at a sufficient height into a reservoir on the edge of the valley. the remains of this bridge leave no doubt that it was purposely destroyed by barbarians; some of the arches near the end of it remain, while the rest have been thrown down, some on one side and some on the other; but happily the arches next to the reservoir, at the end of the bridge and on the edge of the valley, remain, and the reservoir itself is still in part intact, supported on a huge mass of masonry. four holes are to be seen in that part of the front of the reservoir which is left, being the holes from which the lead pipes descended into the valley. there must have been nine of these pipes in all. these holes are elliptical in shape, being in. high by ½ in. wide, and the interior of the reservoir is still seen to be covered with cement. the walls of the reservoir were about ft. in. thick, and were strengthened by ties of iron; it had an arched stone roof in which there was an opening for access. from this the nine lead pipes descended the side of the valley supported on a construction of masonry, crossed the river by an aqueduct bridge, and ascended into another reservoir on the other side, entering the reservoir at its upper part just below the spring of the arches of the roof. from this reservoir the aqueduct passed to the next on the edge of the large and deep valley of bonnan, being underground twice and having three bridges on its course, the last of which, the sixteenth on the course of the aqueduct, ends in a reservoir on the edge of the valley. only one of the openings by which the siphons, of which there were probably ten, started from the reservoir is now left. the bridge across the valley below had thirty arches, and was about ft. long by ft. wide. a number of the arches still remain standing, and, the pillars of the arches were constructed of transverse arches themselves. the work consisted of concrete, formed with roman cement so hard that it turns the points of pickaxes when employed against it, with layers of tiles at regular intervals. the surface of the concrete is covered with small cubical blocks of stone placed so that their diagonals are horizontal and vertical, and forming what is known as _opus reticulatum_. after crossing the bridge the pipes were carried up the other side of the valley into a reservoir, of which little remains, and then the aqueduct was continued to the next valley, passing over three bridges in its course. this valley, that of st. irenée, is much smaller than either of the others, but nevertheless it was deep enough to necessitate the construction of inverted siphons, of which there were eight. leaving the reservoir on the other side of this valley, the aqueduct was carried on a long bridge (the twentieth on its course) which crossed the plateau on the top of fourvieres and opened into a large reservoir, the remains of which are still to be seen on the top of that hill. from this reservoir, which was ft. long and ft. wide, pipes of lead conveyed the water to the imperial palace and to the other buildings near the top of the hill. some of these lead pipes were found in a vineyard near the top of fourvieres at the beginning of the eighteenth century, and were described by colonia in his history of lyons. they are made of thick sheet lead rolled round so as to form a tube, with the edges of the sheet turned upward, and applied to one another in such a way as to leave a small space, which was probably filled with some kind of cement. these pipes, of which it is said that twenty or thirty, each from ft. to ft. long, were found, were marked with the initial letters ti. cl. caes. (tiberius claudius cæsar), and afford positive evidence that the work was carried out under the emperor claudius. lead pipes, constructed in a similar manner, have also been found at bath, in this country, in connection with the roman baths. the great difference between this aqueduct and those near rome arises from the fact that, instead of being carried across a nearly flat country, it was carried across one intersected with deep ravines, and that it was therefore necessary to have recourse to the system of inverted siphons. there can be no doubt that the inverted siphons were made of lead, although no remains of them have been found; for we know that the romans used lead largely, and, as we have seen, pieces of the lead distribution pipes have been found. it is possible, and even likely, that strong cords of hemp were wound round the pipes forming the siphons, as is related by delorme in describing a similar roman aqueduct siphon near constantinople; delorme also describes, in the aqueduct last mentioned, a pipe for the escape of air from the lowest part of the siphon carried up against a tower, which was higher than the aqueduct, and it is certain that there must have been some such contrivance on the siphons of the aqueduct constructed at lyons. flacheron supposes that they consisted of small pipes carried from the lowest part of the siphons up along the side of the valley and above the reservoirs, or, in some instances, of taps fixed at the lowest part of the siphons. the romans have been blamed for not using inverted siphons in the aqueducts at rome, and it has been said that this is a sufficient proof that they did not understand the simplest principles of hydraulics, but the remains of the aqueducts at lyons negative this assumption altogether. the romans were not so foolish as to construct underground siphons, many miles long, for the supply of rome; but where it was necessary to construct them for the purpose of crossing deep valleys, they did so. the same emperor claudius who built the aqueduct at rome known by his name built the aqueduct of mont pila, at lyons, and it is quite clear, therefore, that his engineers were practically well acquainted with the principles of hydraulics. it is thus seen that the ancient romans spared no pains to obtain a supply of pure water for their cities, and i think it is high time that we followed their example, and went to the trouble and expense of obtaining drinking water from unimpeachable sources, instead of, as is too often the case, taking water which we know perfectly well has been polluted, and then attempting to purify it for domestic purposes. * * * * * steam engine economy. by chief engineer john lowe, u.s. navy. the purpose of this article is to point out an easy method whereby any intelligent engineer can determine the point at which it is most economical to cut off the admission of steam into his cylinder. in the attack upon such a problem, it is useful to employ all the senses which can be brought to bear upon it; for this purpose, diagrams will be used, in order that the sense of sight may assist the brain in forming its conclusions. [illustration: steam engine economy.--by john lowe, chief engineer u.s.n.] fig. xabcx is an ideal indicator card, taken from a cylinder, imagined to be feet long, in which the piston, making one stroke per minute, has therefore a piston speed of feet per minute. divide this card into any convenient number of ordinates, distant _dx_ feet from each other, writing upon each the absolute pressure measured upon it from the zero line xx. by way of example, let the diameter of the cylinder be . inches, and let the back pressure from all causes be pounds uniformly throughout. it will be represented by the line b_{ }, b_{ }, etc. this quantity subtracted from the pressures p_{ }, p_{ }, etc., leaves the remainder (p-b) upon each ordinate, which remainder represents the net pressures which at that point may be applied to produce external power. if, now, a is the area of the piston, then the external power (d w) produced between each ordinate is: to any convenient scale, upon each ordinate, set off the appropriate power as calculated by this equation ( ). a(p-b)dx dw = --------------. ( .) , there will result the curve _w, w, w_, determining the power which at any point in the diagram is to be regarded as a gain, to be carried to the credit side of the account. it is evident that, so long as the gains from expansion exceed the losses from expansion, it is profitable to proceed with expansion, but that expansion should cease at that point at which gains and losses just balance each other. to calculate the losses. the requisite data are furnished by the experiments conducted some years since by president d.m. greene, of troy college, for the bureau of steam engineering, u.s. navy. according to these experiments, the heat which is lost per hour by radiation through a metallic plate of ordinary thickness, exposed to dry air upon one side and to the source of heat upon the other, for one degree difference in temperature, is as follows: condition. heat units. naked...................................... . covered with hair felt, . inch thick.... . " " . " .... . " " . " .... . " " . " .... . " " . " .... . " " . " .... . if now t' = temperature of steam at the ordinate, t = temperature of the surrounding atmosphere, ds = surface of the cylinder included between each ordinate, k = that figure from the table satisfying the conditions, then the power loss (dr) per minute will be: k (t'-t)ds dr = ( -- ) ----------. ( ) , to the same scale as the power gains, upon each ordinate, set off the appropriate power loss, as calculated by this equation ( ). there will result the curve r, r, r, which determines the power which at any point in the diagram is to be regarded as a loss, to be carried to the debit side of the account. this curve of losses intersects the curve of gains at a point (it is evident) where each equals the other. therefore this is the point at which expansion should cease, and this absolute pressure is the economic terminal pressure, which determines the number of expansions profitable under the given conditions. in the foregoing example are taken k = . , t' = . , t = , while the back pressure was taken at pounds. by way of further illustration, first let the back pressure be changed from to . by equation there will result a new curve of gains, w, w, w, a portion only being plotted. second, let t' = . as before. t = instead of . k = . instead of . . there will result the second curve of losses, r, r, r, intersecting the second curve of gains at the point f, the new economic point for our new conditions. these two examples fully illustrate the whole subject, furnishing an easy and, when carefully made, a very exact calculation and result. the following are a few of the general conclusions to be drawn: . that radiation is a tangible and measurable cause, sufficient to account for all losses heretofore ascribed to an intangible, immeasurable, and wholly imaginary cause, viz., "internal evaporation and re-evaporation." . in order to prevent the high initial temperatures now used becoming a source of loss, it is necessary to prevent the quantity ds (t'-t) becoming great, by making ds as small as possible. in other words, we must compound our engines. thus for the first time is pointed out the true reason why compound engines are economical heat engines. . the foregoing reasoning being correct, it follows that steam jackets are a delusion. . in order to attain economy, we must have high initial temperatures, small high pressure cylinders, low back pressures from whatsoever cause, high piston speeds, short rather than long strokes, to avoid the cooling effects of a long piston rod; but especially must we have scrupulous and perfect protection from radiation, especially about the cylinder heads, now oftentimes left bare. * * * * * electricity in warfare. [footnote: from a recent lecture before the franklin institute, philadelphia.] by lieut. b.a. fiske, u.s.n. lieutenant fiske began by paying a tribute to the remarkable pioneer efforts of colonel samuel colt, who more than forty years ago blew up several old vessels, including the gunboat boxer and the volta, by the use of electricity. congress voted colt $ , for continuing his experiments, which at that day seemed almost magical; and he then blew up a vessel in motion at a distance of five miles. lieut. fiske next referred briefly to the electrical torpedoes employed in the crimean war and our civil war. at the present day, an electrical torpedo may be described as consisting of a strong, water-tight vessel of iron or steel, which contains a large amount of some explosive, usually gun-cotton, and a device for detonating this explosive by electricity. the old mechanical mine used in our civil war did not know a friendly ship from a hostile one, and would sink either with absolute impartiality. but the electrical submarine mine, being exploded only when a current of electricity is sent through it from ship or shore, makes no such mistake, and becomes harmless when detached from the battery. the condition of the mine at any time can also be told by sending a very minute current through it, though miles away and buried deep beneath the sea. when a current of electricity goes through a wire, it heats it; and if the current be made strong enough, and a white hot wire thus comes in contact with powder or fulminate of mercury in a torpedo, an explosion will result. but it is important to know exactly when to explode the torpedo, especially during the night or in a fog; and hence torpedoes are often made automatic by what is called a circuit closer. this is a device which automatically bridges over the distance between two points which were separated, thus allowing the current to pass between them. in submarine torpedoes it is usual to employ a small weight, which, when the torpedo is struck, is thrown by the force of the blow across two contact points, one of which points is in connection with the fuse and the other in connection with the battery, so that the current immediately runs over the bridge thus offered, and through the fuse. in practice, these two contact points are connected by a wire, even when the torpedo is not in the state of being struck; but the wire is of such great resistance that the current is too weak to heat the wire in the fuse. yet when the weight above mentioned is thrown across the two contact points, the current runs across the bridge, instead of through the resistance wire, and is then strong enough to heat the wire in the fuse and explode the torpedo. the advantage of having a wire of high resistance between the contact points, instead of having no wire between them, is that the current which then passes through the fuse, though too weak to fire it, shows by its very existence to the men on shore that the circuit through the torpedo is all right. but instead of having the increased current caused by striking the torpedo to fire the torpedo directly, a better way is to have it simply make a signal on shore. then, when friendly vessels are to pass, the firing battery can be disconnected; and when the friendly ship bumps the torpedo, the working of the signal shows not only that the circuit through the fuse is all right, but also that the circuit closer is all right, so that, had the friendly ship been a hostile ship, she would certainly have been destroyed. while the management of the torpedo is thus simple, the defense of a harbor becomes a complex problem, on account of the time and expense required to perfect it, and the training of a corps of men to operate the torpedoes. in order to detect the presence of torpedoes in an enemy's harbor, an instrument has been invented by capt. mcevoy, called the "torpedo detecter," in which the action is somewhat similar to that of the induction balance, the iron of a torpedo case having the effect of increasing the number of lines of force embraced by one of two opposing coils, so that the current induced in it overpowers that induced in the other, and a distinct sound is heard in a telephone receiver in circuit with them. as yet, this instrument has met with little practical success, but, its principle being correct, we can say with considerable confidence that the reason of its non-success probably is that the coils and current used are both too small. lieut. fiske described the spar torpedo and the various classes of movable torpedoes, including the lay. his conclusion is that the most successful of the movable torpedoes is the simms, with which very promising experiments have been conducted under the superintendence of gen. abbot. recent experiments in england have shown that the whitehead torpedo, over which control ceases after it is fired, is not so formidable a weapon when fired at a ship _under way_ as many supposed, for the simple reason that it can be dodged. but an electrical torpedo, over which control is exercised while it is in motion through the water, cannot be dodged, provided it receives sufficient speed. for effective work against ships capable of steaming fifteen knots per hour, the torpedo should have a speed of twenty knots. there is no theoretical difficulty in the way of producing this, for a speed of eleven knots has already been recorded, though an electric torpedo, to get this speed, would have to be larger than a whitehead having the same speed. it may be conceived that a torpedo carrying lb. of gun-cotton, capable of going knots per hour, so that it would pass over a distance of yards in about sec., and yet be absolutely under control all the time, so that it can be constantly kept pointed at its target, would be a very unpleasant thing for an enemy to meet. military telegraphy is a second use of electricity in warfare. lieut. fiske traces its origin to our own civil war. foreign nations took the hint from us, and during the invasion of france the telegraph played a most important part. in military telegraph trains, miles of wire are carried on reels in specially constructed wagons, which hold also batteries and instruments. some of the wire is insulated, so that it can rest on the ground, and thus be laid out with great speed, while other wire is bare, and is intended to be put on poles, trees, etc. for mountain service the wires and implements are carried by pack animals. regularly trained men are employed, and are drilled in quickly running lines, setting up temporary stations, etc. in the recent english operations in egypt, the advance guard always kept in telegraphic communication with headquarters and with england, and after the battle of tel-el-kebir news of the victory was telegraphed to the queen and her answer received in forty-five minutes. the telephone is also used with success in warfare, and in fact sometimes assists the telegraph in cases where, by reason of the haste with which a line has been run, the current leaks off. a telephone may then be used to receive the message--and for a transmitter a simple buzzer or automatic circuit breaker, controlled by an ordinary key. in the case of vessels there is much difficulty in using the telegraph and the telephone, as the wire may be fouled and broken when the ship swings by a long chain. in england in the case of a lightship this difficulty has been surmounted, or rather avoided, by making hollow the cable by which the ship rides, and running an insulated wire along the long tube thus formed inside. but the problem is much simplified when temporary communication only is desired between ships at anchor, between a ship and the shore, or even between a ship and a boat which has been sent off on some special service, such as reconnoitering, sounding, etc. in this case portable telephones are used, in which the wire is so placed on a reel in circuit with the telephone that communication is preserved, even while the wire is running off the reel. the telegraph and telephone are both coming largely into use in artillery experiments, for example, in tracking a vessel as she comes up a channel so that her exact position at each instant may be known, and in determining the spot of fall of a projectile. in getting the time of flight of projectiles electricity is of value; by breaking a wire in circuit with a chronograph, the precise instant of start to within a thousandth of a second being automatically registered. velocimeters are a familiar application of electricity somewhat analogous. in these, wires are cut by the projectile at different points in its flight, and the breaking of the electric current causes the appearance of marks on a surface moving along at a known speed. the velocity of the projectile in going from one wire to another can then be found. electricity is also used for firing great guns, both in ships and forts. in the former, it eliminates the factor of change produced by the rolling of the ship during the movement of the arm to fire the gun. the touch of a button accomplishes the same thing almost instantaneously. moreover, an absolutely simultaneous broadside can be delivered by electricity. the officer discharges the guns from a fighting tower, whither the wires lead, and the men can at once lie down out of the enemy's machine guns, as soon as their own guns are ready for discharge. the electric motor will certainly be used very generally for handling ordnance on board ships not very heavily plated with armor, since a small wire is a much more convenient mode of conveying energy to a motor of any kind, and is much less liable to injury, than a comparatively large pipe for conveying steam, compressed air, or water under pressure. besides, the electric motor is the ideal engine for work on shipboard, by reason of its smooth and silent motion, its freedom from dirt and grease, the readiness with which it can be started, stopped, and reversed, and its high efficiency. indeed, in future we may look to a protected apparatus for all such uses in every fort and every powerful ship. in photographing the bores of great guns, electric lights are used, and they make known if the gun is accurately rifled and how it is standing the erosion of the powder gases. in the case of a fort, electricity can be employed in connection with the instruments used for determining at each instant the position of an approaching vessel or army. whitehead torpedoes are now so arranged that they can be ejected by pressing an electric button. electric lights for vessels are now of recognized importance. at first they were objected to on the ground that if the wire carrying the current should be shot away in action, the whole ship would be plunged in darkness; and so it would be in an accident befalling the dynamo that generates the current. the criticism is sensible, but the answer is that different circuits must be arranged for different parts of the ship, and the wires carrying the current must be arranged in duplicate. it is also easy to repair a break in a copper wire if shot away. as to the dynamo and engines, they must be placed below the water line, under a protective deck, and this should be provided for in building the vessel. there should be several dynamos and engines. all the dynamos should, of course, be of the same electromotive force, and feed into the same mains, from which all lamps draw their supply, and which are fed by feeders from the dynamo at different points, so that accident to the mains in one part of the ship will affect that part only. but it is the arc light, used as what is called a search light, that is most valuable in warfare. lieut. fiske thinks its first use was by the french in the siege of paris, to discover the operations of the besiegers. it can be carried by an army in the field, and used for examining unknown ground at night, searching for wounded on the battle field, and so on. on fighting vessels the search light is useful in disclosing the attack of torpedo boats or of hostile ships, in bringing out clearly the target for guns, and in puzzling an enemy by involving him successively in dazzling light and total darkness. lieut. fiske suggests that this use would be equally effective in embarrassing troops groping to the attack of a fort at night by sudden alternations of blinding light and paralyzing darkness. there should be four search lights on each side of a ship. as to the power and beauty of the search light, lieut. fiske refers to the magnificent one with which he lighted up philadelphia last autumn, during the electric exhibition in that city. one night he went to the tower of the pennsylvania railroad station and watched the light stationed at the exhibition building on d street. the ray of light when turned at right angles to his direction looked like a silver arrow going through the sky; and when turned on him, he could read the fine print of a railroad time table at arm's length. flashes from his search light were seen at a distance of thirty miles. in using incandescent lamps for night signaling, the simplest way is to arrange a keyboard with keys marked with certain numbers, indicating the number of lamps arranged in a prominent position, which will burn while that key is being pressed. for example, suppose the number means "prepare to receive a torpedo attack." press keys , , , , and the lights of lamps , , , , successively blaze out. electrical launches have been used to some extent, their storage batteries being first charged ashore or on board the ship to which the launch belongs. they have carried hundreds of people, and have made eight knots an hour. the improvement of storage batteries, steadily going on, will eventually cause the electrical launch to replace the steam launch. one of its advantages is in having no noise from an exhaust and no flame flaring above a smoke pipe to betray its presence. in warfare two sets of storage batteries should be provided for launches, one being recharged while the other is in use. mr. gastine trouse has recently invented "an electric sight," a filament of fine wire in a glass tube covered with metal on all sides save at the back. the battery is said to be no larger than a man's finger, and to be attached to the barrel near the muzzle by simple rubber bands, so arranged that the act of attaching the battery to the barrel automatically makes connection with the sight; and so arranged also that the liquid of the battery is out of action except when the musket is brought into a horizontal position for firing. to throw a good light upon the target the same inventor has devised a small electric lamp and projector, which is placed on the barrel near the muzzle by rubber bands, the battery being held at the belt of the marksman, with such connections that the act of pressing the butt of the musket against the shoulder completes the circuit, and causes the bright cylinder of light to fall on the target, thus enabling him to get as good a shot as in the day time. search lights and incandescent lights are advantageously used with balloons. in submarine boats electricity will one day be very useful. submarine diving will play a part in future wars, and the diver's lamp will be electrical. progress has been made also in constructing "electrical guns," in which the cartridge contains a fuse which is ignited by pressing an electric button on the gun. a better aim can be had with it, when perfected, than with one fired by a trigger. at present, according to lieut. fiske, this invention has not reached the practical stage, and the necessity for a battery to fire a cartridge is decidedly an objection. but the battery is very small, needs little care, and will last a long time. the hard pull of the ordinary trigger causes a movement of the barrel except in the hands of the most highly skilled marksmen, and this hard pull is a necessity, because the hammer or bolt must have considerable mass in order to strike the primer with sufficient force to explode it. having the mass, it must have considerable inertia; hence it needs a deep notch to hold it firm when jarred at full cock, and this deep notch necessitates a strong pull on the trigger. but with an electric gun the circuit-closing parts are very small and light, and can be put into a recess in the butt of the gun, out of the way of chance blows. thus a light pressure of the finger is alone needed to fire it, while from the small inertia of the parts a sudden shock will not cause accidental closing of the circuit and firing of the gun. * * * * * meucci's claims to the telephone. our readers have already been informed through these columns that, notwithstanding the refusal of the attorney-general, mr. garland, to institute suit for the nullification of the bell patent, application has again been made by the globe telephone co., of this city, the washington telephone co., of baltimore, and the panelectric co. these applications have been referred to the interior department and patent office for examination, and upon their report the institution of the suit depends. the evidence which the companies above mentioned have presented includes not only the statement of prof. gray and the circumstances connected with his caveat, but brings out fully, for the first time, the claims of antonio meucci. [illustration: meucci's caveat, .] the latter evidence is intended to show that meucci invented the speaking telephone not only before bell, but that he antedated reis by several years. in a recent interview with meucci we obtained a brief history of his life and of his invention, which will, no doubt, interest our readers. meucci, a native of italy, was educated in the schools of florence, devoting his time as a student to mechanical engineering. in he gave considerable attention to the subject of electricity, and had a contract with the government of the island of cuba to galvanize materials used in the army. while experimenting with electricity he read the works of becquerel, mesmer, and others who treated largely of the virtues of electricity in the cure of disease. meucci made experiments in this direction, and at one time thought that he heard the sound of a sick person's voice more distinctly than usual, when he had the spatula connected with the wire and battery in his mouth. [illustration: figs. and .-- .] the apparatus he used for this purpose is shown in fig. . it consists of an oval disk or spatula of copper attached to a wire which was coiled and supported in an insulating handle of cork. to ascertain that he was able to hear the sound, he covered the device with a funnel of pasteboard, shown in the adjoining figure, and held it to his ear, and thought that he heard the sound more distinctly. these instruments were constructed in in havana, where meucci was mechanical director of a theater. in may, , he came to this country, and settled in staten island, where he has lived ever since. it was not until a year later that he again took up his telephonic studies, and then he tried an arrangement somewhat different from the first. he used a tin tube, figs. and , and covered it with wire, the ends of which were soldered to the tongue of copper. with this instrument, he states, he frequently conversed with his wife from the basement of his house to the third floor, where she was confined as an invalid. [illustration: figs. and .-- .] continuing his experiments, he conceived the idea of using a bobbin of wire with a metallic core, and the first instrument he constructed on this idea is shown in fig. . it consisted of a wooden tube and pasteboard mouth piece, and supported within the tube was a bundle of steel wires, surrounded at their upper end by a bobbin of insulated wire. the diaphragm in this instrument, was an animal membrane, and it was slit in a semicircle so as to make a flap or valve which responded to the air vibrations. this was the first instrument in which he used a bobbin, but the articulation naturally left much to be desired, on account of the use of the animal membrane. meucci fixes the dates from the fact that garibaldi lived with him during the years - , and he remembers explaining the principles of his invention to the italian patriot. after constructing the instrument just described, meucci devised another during - . this consisted of a wooden block with a hole in the center which was filled with magnetic iron ore, and through the center of which a steel wire passed. the magnetic iron ore was surrounded by a coil of insulated copper wire. but an important improvement was introduced here in the shape of an iron diaphragm. with this apparatus greatly improved effects were obtained. [illustration: fig. .-- .] in meucci first tried, he says, a horseshoe magnet, as shown in fig. , but he went a step backward in using an animal membrane. he states that this form did not talk so well as some which he had made before, as might be expected. during the years - meucci constructed the instrument shown in fig. . he here employed a core of tempered steel magnetized, and surrounded it with a large coil. he used an iron diaphragm, and obtained such good results that he determined to bring his invention before the public. his national pride prompted him to have the invention first brought out in italy, and he intrusted the matter to a mr. bendalari, an italian merchant, who was about to start for that country. bendalari, however, neglected the matter, and nothing was heard of it from that quarter. at the same time meucci described his invention in _l'eco d'italia_, an italian paper published in this city, and awaited the return of bendalari. meucci, however, kept at his experiments with the object of improving his telephone, and several changes of form were the result. fig. shows one of these instruments constructed during - . it consisted of a ring of iron wound spirally with copper wire, and from two opposite sides iron wires attached to the core supported an iron button. this was placed opposite an iron diaphragm, which closed a cavity ending in a mouthpiece. he also constructed the instrument which is shown in fig. , and which, he says, was the best instrument he had ever constructed. the bobbin was a large one, and was placed in a soapbox of boxwood, with magnet core and iron diaphragm. still seeking greater perfection, meucci, in , tried the bent horseshoe form, shown in fig. , but found it no improvement; and, although he experimented up to the year , he was not able to obtain any better results than the best of his previous instruments had given. [illustration: fig. .-- .] when meucci arrived in this country, he had property valued at $ , , and he entered into the brewing business and into candle making, but he gradually lost his money, until in he found himself reduced to little or nothing. to add to his misery, he had the misfortune of being on the staten island ferryboat westfield when the latter's boiler exploded with such terrible effect in . he was badly scalded, and for a time his life was despaired of. after he recovered he found that his wife, in their poverty, had sold all his instruments to john fleming, a dealer in second-hand articles, and from whom parts of the instruments have recently been recovered. [illustration: fig. .-- - .] with the view of introducing his invention, meucci now determined to protect it by a patent; and having lost his instrument, he had a drawing made according to his sketches by an artist, mr. nestori. this drawing he showed to several friends, and took them to mr. a. bertolino, who went with him to a patent attorney, mr. t.d. stetson, in this city. mr. stetson advised meucci to apply for a patent, but meucci, without funds, had to content himself with a caveat. to obtain money for the latter he formed a partnership with a.z. grandi, s.g.p. buguglio, and ango tremeschin. the articles of agreement between them, made dec. , , credit meucci as the inventor of a speaking telegraph, and the parties agree to furnish him with means to procure patents in this and other countries, and to organize companies, etc. the name of the company was "teletrofono." they gave him $ with which to procure his caveat, and that was all the money he ever received from this source. the caveat which meucci filed contained the drawing made by nestori, and as shown in the cut, which is a facsimile, represents two persons with telephones connected by wires and batteries in circuit. the caveat, however, does not describe the invention very clearly; it describes the two persons as being insulated, but meucci claims that he never made any mention of insulating persons, but only of insulating the wires. to explain this seeming incongruity, it must be stated that meucci communicated with his attorney through an interpreter, as he was not master of the english language; and even at the present time he understands and speaks the language very poorly, so much so that we found it necessary to communicate with him in french during the conversation in which these facts were elicited. [illustration: fig. .-- - .] in the summer of , after obtaining his caveat, meucci, accompanied by mr. bertolino, went to see mr. grant, at that time the vice president of the new york district telegraph company, and he told the latter that he had an invention of sound telegraphs. he explained his inventions and submitted drawings and plans to mr. grant, and requested the privilege of making a test on the wires of the company, which test if successful would enable him to raise money. mr. grant promised to let him know when he could make the test, but after nearly two years of waiting and disappointment, mr. grant said that he had lost the drawings; and although meucci then made an instrument like the one shown in fig. for the purpose of a test, mr. grant never tried it. meucci claims that he made no secret of his invention, and as instance cites the fact that in a diver by the name of william carroll, having heard of it, came to him and asked him if he could not construct a telephone so that communication could be maintained between a diver and the ship above. meucci set about to construct a marine telephone, and he showed us the sketch of the instrument in his memorandum book, which dates from that time and contains a number of other inventions and experiments made by him. [illustration: fig. .-- - .] [illustration: fig. .-- .] when professor bell exhibited his inventions at the centennial, meucci heard of it, but his poverty, he claims, prevented him from making his protestations of priority effective, and it was not until comparatively recently that they have been brought out with any prominence.--_the electrical world._ * * * * * an electrical centrifugal machine for laboratories. [footnote: paper read before section b, british association, aberdeen meeting.] by alexander watt, f.i.c., f.c.s. the late dr. mohr[ ] of bonn, advocated the use of a centrifugal machine as a means of rapidly drying crystals and crystalline precipitates; but although they are admirably adapted for that purpose, centrifugal machines are seldom seen in our chemical laboratories. [footnote : "lehrb. d. chem. analyt. titrirmethode," d ed., , p. .] the neglect of this valuable addition to our laboratory apparatus is probably owing to the inconvenience involved in driving the machine at a high speed by means of the ordinary hand driving gear, especially when the rotation has to be maintained for a considerable length of time. it occurred to me, therefore, that by attaching the drum or basket of the machine (or the rotating table of mohr's apparatus) directly to the spindle of an electro-motor, the difficulty of driving might be got over, and at the same time a combination of great efficiency would result, as the electro-motor, like the centrifugal machine, is most efficient when run at a high speed. the apparatus shown in the sketch consists essentially of a perforated basket, a, which is slipped on to a cone attached to the spindle, s, of an electro-motor, and held in position by the nut, d. the casing, b, with its removable cover, c, serves to receive the liquid driven out of the substance being dried. a flat form of the ordinary siemens h armature, e, revolves between the poles, p, of the electro-magnets, m, which are connected by means of the base plate, i. the brass cross-bar, g, carries the top bearing of the spindle, s, and prevents the magnet poles from being drawn together. [illustration] from four to six cells of a bichromate battery or faure secondary battery furnish sufficient power to run the machine at a high speed. an apparatus with a copper basket four inches in diameter has been found extremely useful in the laboratory for drying such substances as granulated sulphate of copper and sulphate of iron and ammonia, but more especially for drying sugar, which when crystallized in very small crystals cannot be readily separated from the sirupy mother-liquor by any of the usual laboratory appliances. for drying substances which act on copper the basket may be made of platinum or ebonite; in the latter case, owing to the increased size of the perforations, it may be necessary to line the basket with platinum wire gauze or perforated parchment paper. * * * * * transmission of power by electricity. the experiments of m. marcel deprez have entered on a decisive phase. the dynamos are completed, and were put in place on the th october, when m. deprez carried out some preliminary tests in the presence of a commission consisting of mm. collignon, inspector-general des ponts et chaussées; delebecque, ingenieur en chef du materiel et de la traction of the northern railway of france; contanini, engineer in the same company; and sartaux. the generating dynamos made by mm. breguet, and the receiving dynamos constructed by mm. mignon and rouart, were during a preliminary trial placed side by side, one portion of the circuit being very short, and the other twice the distance between la chapelle and creil, or seventy miles. in future experiments the two dynamos will be placed in their normal positions at each end of the line. the generating machine is driven by a locomotive engine; the resistance of its field magnets is . ohms, and of the two armatures ohms. the resistance of the two armatures of the receiving machine is . ohms, and the resistance of the line is ohms; the generator and receiver field magnets are excited each by a separate machine. five different trials were made at varying speeds of the driving shaft; the initial work on this shaft was measured by a dynamometer, and the available energy of the shaft of the receiving machine was ascertained by a prony brake; the other results of the experiments were deduced from the constants of the machines and from galvanometric measurements. for the first trials the different elements were as follows: . _generating dynamos:_ velocity of shaft revolutions. electromotive force at terminals, . volts. " " total . " available work at driving shaft. h. p. electrical work of generator . " difference absorbed . " . _line:_ work absorbed by the line. . h. p. . _receiving dynamos:_ velocity of shaft revolutions. electromotive force at terminals, . volts. " " total . " electrical work of receiver . h. p. available work on shaft . " difference absorbed " the duty obtained would thus be . / = . per cent., if the work absorbed by the exciting machines be not considered. taking this into account, it would be reduced to per cent. in subsequent experiments the speed of the generator was increased gradually. in the last trial the following were the elements: . _generating dynamos:_ speed of shaft revolutions. electromotive force at terminals . volts. " " total . " available work on driving shaft, h. p. electrical work on generator . " difference absorbed . " work absorbed by armature . " . _line:_ work absorbed by conductors . h. p. . _receiving dynamos_: speed of shaft revolutions. electromotive force at terminals volts. electromotive force total . " electrical work of receiver . h. p. work measured on receiver shaft . " difference absorbed . " duty obtained, not including exciting machine per cent. duty obtained, including exciting machine " during the various experiments the current traversing the line varied from . amperes to . amperes. no heating of any kind was observed. m.j. bertrand, who communicated a paper to the academy of sciences on the subject, commented on the relatively low speeds. it corresponds to a linear displacement of the surface armatures, in no case exceeding the speed of a locomotive wheel. the tension reached , volts., under very satisfactory mechanical conditions, and with a current that in no way endangered the line. this first experiment is certainly encouraging, and it will be followed by others of a more complete and exhaustive character. mm. de rothschild are now embodying a powerful commission of french and foreign scientists who will follow the subject carefully, and report upon it. it may be safely predicted that one result of this action will be the development of a new series of observations of the highest technical interest and value.--_engineering._ * * * * * the locked and corded box trick. the trick with the locked and corded box, i believe, is an old one, though perhaps not in its present form. in late years it has been revived with improvements, and popularized by those clever illusionists, messrs. maskelyne & cook and dr. lynn, at the egyptian hall. there are several ways of working the trick or, rather, of arranging the special bit of mechanism wherein the peculiar features of the box consist. the one i am about to describe is, i think, the best of those i am acquainted with, or at liberty to divulge. indeed, i don't know that any method is better, and this one has the advantage over most others of allowing the performer to get into as well as out of the box, without leaving a trace of his means of ingress. it will be seen the box is paneled, and all the panels look equally firm and fixed. as a matter of fact, one of the panels is movable, though the closest scrutiny would fail to discover this if the box and fittings are carefully made and adjusted. fig. shows the general appearance of the box, of which the back is the same as the front. in the box i describe, the end marked + has a movable panel. the size of the box should be regulated by the size of the performer; but one measuring feet inches long by feet back to front, and inches high, exclusive of the lid, which may be inches, will be of general use. in making the box it is most important that all sides and panels look alike, and that nothing special in the appearance of the end with the loose panel should attract notice. fig. shows this end with fittings drawn half of full size, and it will he seen from this that the framing, a, is inches wide by ¼ inches thick, and the panel, b, ½ inch thick. [illustration: fig. .] it will be noticed that the top and bottom rails of the frame are rabbeted to receive the panel, but the sides are grooved, the groove in front rail being double the depth of the one in the back rail. [illustration: the locked and corded box trick. by david b. adamson.] the dotted line, b, shows the size of the panel; the dotted line, c, shows the depth of groove in the front rail. from this it will be clear that the panel is only held in place at the back and front, and that on sliding it toward the front it will be free out of the groove in the back rail. three sides of it are thus free, and a little manipulation will allow of its being taken out altogether, leaving plenty of space for the performer to get out, presuming him to have been locked inside the box. if the panel were to be finished in this way, without further fittings, the secret would soon be discovered; and i now proceed to show how the panel is held in place and firm while under examination. determine the size of screws that are to be used in fixing the brass corner clamps. let us say no. is decided on; and if brass screws are used, then get a piece of brass, fig. , the exact diameter of the screw-head, and a little longer than the thickness of the framing. if iron screws are to be used, then this piece must be iron. now bore a hole into which this bolt will fit closely, right through the framing at d, fig. . it is most important that the hole should be made close up to the edge of the panel, b, so that when the bolt is in it firmly holds the panel, and prevents it moving from back to front in the grooving. now get a piece of sheet brass, / inch thick, and cut it to the shape shown by e, fig. . the width of this piece should not be less than / inch, and it must be of such length that the end reaches to the middle of the top framing, as shown at l, fig. . this piece of brass is sunk in the top and front framing, as shown by the dotted lines, g, in figs. and , and also in section in the latter. when the box is open, the lower or short arm of this lever, which is shaped as shown full size, at e, fig. , is kept pressed down on the bolt, d, as shown by the dotted lines, e, e, e, fig. , and e, fig. , by of the spring, j, fig. . on the box being closed, a pin on the under edge of lid goes into the hole, l, fig. , and presses the end of the lever down in such a way as to raise the claw end of it from d. the thick dotted lines, f, f, f, fig. , show position of lever when box is closed. it will be noted that the bolt, d, fig. , has a groove cut in it all around, into which the claw fits. this prevents the bolt being pushed backward or forward when the box is open. the lever must be hung as shown, k, fig. . the exact position of this is immaterial, but it is as well to have the fulcrum as near the end as may be, in order that the claw may be raised sufficiently with only a small movement of the short arm of the lever. of course, the shorter the arm is, the more accurately the lid and pin must be made to close. if the pin, pressing short arm down, be too short, the pressure will not be enough to release the claw, and consequently the performer might find himself really unable to get out of the box after it is locked. the end of the lever should be finished with a wood block, as fig. , larger than the pin on the lid, as represented by l and m, fig. . the block may be of other material, but should be colored the same as the wood the box is made of, so that, if any one were to look down on it, no suspicion would be aroused, as might be were plain brass used. [illustration: fig .] [illustration: fig .] in fig. , i show an easy way of hanging the lever. it is simply a piece of wire sharpened and notched, so as to form several small barbs, preventing withdrawal. the mode of fixing will be easily understood by reference to b and c, fig. . some considerable amount of care will have to be bestowed on fitting and adjusting this part of the work, on which the successful performance of the trick consists, and before finally fixing up, it should be ascertained that all the movements work harmoniously. it will be best to cut the groove in which the lever works from below, and, after the lever is fixed, to fill up the space not required by the lever with strips of wood, h, h. if preferred, the space can be shaped out from the back, i.e., the inside of the framing, and then filled where not required, but as this, however neatly done, would show a joint which might be detected by sharp eyes, it is better to cut from below, though more troublesome. the end containing the movable panel being arranged, make up the rest of the box to it, taking care to make the rebates of the top and bottom frames to correspond with those of the end. the other panels should not, however, depend on the grooves on two sides only, but at tops and bottoms as well. [illustration: fig. .] [illustration: fig. . & fig. .] [illustration: fig. .] the rebates are to be cut only to have all the framing inside look alike; and as the panel, b, is made to fit quite close into the rebate, it will not be surmised that it is not fitted in the usual way. after the box is made and fitted together, the clamping must be done. the only necessity for this is in order that the bolt, d, which we have seen is made on the outside end exactly to match the screws used to fasten the clamps, should not be conspicuous, as it would be were it alone. as it is, it will not be specially observable, being apparently only one of the screws to fasten the clamps. the clamps may be of thin brass or iron, shaped as shown at fig. . one of the corner holes must be arranged to cover d exactly, and the others regulated to it. let us suppose that a, fig. , is the one through which the bolt goes; the other corner screw holes must be equally distant from the edges of the clamps. twelve of these clamps will be needed. after they have been screwed on, put the bolt through, and let the claw of the lever hold it in place. then mark and cut the bolt flush with the clamp, making a hollow on the end of it to imitate the screws, as d, fig. . the other end of the bolt should either be made flush with the inside of frame and colored to match it, or, better, cut short and faced flush with a piece of wood to match the framing. if a piece of wood with a knot be chosen for this side of the frame, so much the better. immediately over the hole, l, a wooden pin should be fixed in the lid, and of such length that it will press the short arm of lever down sufficiently. it should fit the hole pretty closely. at the other end, a corresponding pin and hole should be made, and, say, two along the front. these will then look as if they were intended merely as fittings to hold the lid in position. the lid at the other end of the box from the movable panel should have a stop of some sort; the ordinary brass joint stop will do as well as any, and should be strong. the reason for placing it at what i may call "the other end" is that, when the box is being examined, it will attract notice, and draw attention from the movable panel end. we may now finally adjust the loose panel, which must fit tight at top and bottom, and be slightly beveled, as shown on section. two holes must also be cut through it, at such a distance from each other that a finger and thumb can be put through them, so as to allow of the panel being moved. in the deep grooving in front also put a couple of springs, say pieces of clock springs, as shown, i, i, fig, . these serve to assist the bolt, d, by pushing the panel into position. holes to match those in end panel must also be cut in the other panels, and when a lock, preferably a padlock, has been fitted, the box is complete. i don't know whether it is necessary to say that the lid should be hinged at the back, and of course it will add to the appearance of the box if it be polished or oiled. now, for those who may not have seen the locked and corded box trick performed, a few words of caution may not be out of place. don't forget to have something in a pocket easily got at that will serve to push the bolt out, before going into the box. a piece of stout wire, a small pencil case, or anything of that sort will do. be careful when getting into the box to lie with your head toward the loose panel end, and face toward the front--as there will be no space to turn round; the right hand will then be uppermost and free to push the bolt out. having done this, grasp the panel with the finger and thumb by means of the two holes, push it to the front of the box, when the back edge will be clear of the groove. it can now easily be pulled into the box, and the performer can creep out. when out, refix panel and bolt so that everything looks as it was. any cording that may be over the end of the box will give sufficiently to allow of exit. i have, i think, made it quite clear that padlock and ropes have nothing to do with the real performance of the trick, but they serve to mystify spectators, who may be allowed to knot the rope and seal the knots in any way they choose. there must always be a screen or curtain to hide the box from the spectators while the performer is getting in or out.--_d.b. adamson, in amateur work._ * * * * * prices of metals. the _metallarbeiter_ remarks that metals have in most cases experienced a reduction in value of late years, this depreciation being attributed in some measure to the cheaper methods of obtaining metals as well as to the discovery of new sources of mineral wealth. the following comparative table shows the approximate prices of various metals in december, , and december, : dec., . dec., . per lb. per lb. £ s d. £ s. d. osmium iridium gold platinum thallium magnesium potassium silver (in hamburg) aluminum cobalt sodium nickel bismuth cadmium quicksilver (in london) tin (in berlin) copper (" " ) arsenic - / antimony - / (" " ) lead - / (" " ) - / zinc - / (" " ) - / steel - / ( in - / bar iron - / upper - / pig iron - / silesia ) - / gold now ranks highest in value of all metals, the competition of osmium and iridium having been over come. it is only by reason of improved methods of preparation that the latter have become cheaper, while their use has at the same time increased. iridium is mixed with platinum in order to increase its strength and durability. the normal standards of the metrical system are made of platinum-iridium on account of its known immutabilty. in , platinum stood per cent. below its present value; but its increased employment for industrial purposes led to the subsequent improvement in price. thallium has experienced a severe depreciation on account of the economical process by which it is extracted from the residue of the lead chambers used in the manufacture of sulphuric acid. the use of this metal is mainly confined to experimental purposes. the fall in silver has arisen from increased production and diminished use for coinage. magnesium was scarcely of any industrial value prior to the fall in price now recorded. improved processes for its treatment have successfully engaged the attention of scientific men, and it is now capable of being used as an alloy with other metals. the salindres factory regulates the price to a certain extent, and its system of working is regarded as a guide in the various processes connected with this branch of industry. the manufacture of potassium and sodium will, it is expected, be more fully elucidated than hitherto, by means of researches made at schering's charlottenburg factory. the course of nickel prices illustrates the stimulus to economical production afforded by an increased consumption. this latter fact is principally due to the employment of nickel for coinage, as alloy for alfenide, etc. the use of cadmium is materially restricted by its relatively limited supply. hitherto, its only source was in the incidental products of zinc distillation, but of late it has been attempted to bring it into solution from its oxide combinations. an increased employment of cadmium for industrial purposes is expected to follow. production in excess of the demand has caused the depreciation recorded in tin, and various other metals not commented upon, this remark applying even to the scarce metals, arsenic and antimony. even the better marks of cornwall tin and mansfield refined copper have had to follow the downward course of the market. * * * * * a perpetual calendar. the annexed figure represents a perpetual calendar, which any one can construct for himself, and which permits of finding the day that corresponds to a given date, and conversely. the apparatus consists of a certain number of circles and arcs of circles divided by radii. the ring formed by the two last internal circles is divided into equal parts, which bear the names of the week, the first seven letters of the alphabet in reversed order, and two signs x. the circle formed by the external circumference of the ring constitutes the movable part of the apparatus, and revolves around its center. two circular sectors, which are diametrically opposite, are each divided into seven parts and constitute the fixed portions. in the divisions of the upper sector are distributed the months, according to the order of the monthly numbers. in the other sector the days of the month are regularly distributed. in order to render the affair complete, a table is arranged upon the movable disk for giving the annual numbers, or rather, in this case, the annual letters. the calendar is used as follows: say, for example, we wish to find what days correspond to the different dates of august, ; we look in the table for the letter (d) that corresponds to this year; then we bring this letter under the given month (august) and the days marked upon the movable disk corresponding to the dates sought, and it only remains to make a simple reading. [illustration: perpetual calendar.] it will be seen that the leap-years correspond to two letters. we here employ the first to feb. inclusive, and the second for the balance of the year. the calendar may be made of cardboard, and be fixed to wood.--_la nature._ * * * * * an accomplished parrot. around the door of a sixth ave. bird store near twenty-third st. was gathered the other day a crowd so large that it was a work of several minutes to gain entrance to the interior. from within there proceeded a hoarse voice dashed with a suspicion of whisky, which bellowed in irish-american brogue the enlivening strains of "peek-a-boo." with each reiteration of "peek-a-boo" the crowd hallooed with delight, and one small boy, in the exuberance of his joy, tied himself into a sort of knot and rolled on the pavement. suddenly the inebriated irishman came to a dead stop, and another voice, pleasanter in quality, sang the inspiring national ode of "yankee doodle," followed by the stentorian query and answer all in one, "how are the psi-upsilon boys? oh, they're all right!" a passer-by, puzzled at the scene, made his way into the store and soon solved the mystery. in a large cage in the center was an enormous green and yellow parrot, which was hanging by one foot to a swinging perch, and trolling forth in different voices with the ease of an accomplished ventriloquist. he resumed a normal position as he was approached, and flapping his wings bellowed out, "hurrah for elaine and logan!" then, cocking his head on one side, he dropped into a more conversational tone, and with a regular "alice in wonderland" air remarked: "it's never too late to mend a bird in the hand;" and again, after a pause, "it's a long lane that never won fair lady." his visitor affably remarked: "you're quite an accomplished bird, polly," and quick as a flash the creature replied: "i can spell, i can. c-a-t, cat. d-o-g, fox," with an affectation of juvenility which was grewsome. he resented an ill-advised attempt at familiarity by snapping at the finger which tried to scratch his poll, and barked out: "take care! i'm a bad bird, i am. you betcher life!" "he's one of the cleverest parrots i have had for some time," said his owner, mr. holden. "in fact, he is almost as good as ben butler, whom i sold to patti. his stock of proverbs seems inexhaustible, and he makes them quite funny by the ingenious way in which he mixes them up. i could not begin to tell you all the things he says, but his greatest accomplishment is his singing. he is a double yellowhead--the only species of parrot which does sing. the african grays are better talkers, but they do not sing. they only whistle. what do i ask for him? oh, i think $ is cheap for such a paragon, don't you?"--_n.y. tribune._ * * * * * the roscoff zoological laboratory. the celebrated roscoff zoological station was founded in , and has therefore been in existence for thirteen years; but it may be said that it has changed appearance thirteen times. those who, for the last six or seven years, have gone thither to work with diligence find at every recurring season some improvement or new progress. a rented house, a small shed in a yard, little or no apparatus, and four work rooms--such was the debut of the station; and modest it was, as may be seen. later on, the introduction of a temporary aquarium, which, without being ornamental, was not lacking in convenience, sufficed for making some fine discoveries regarding numerous animals. a small boat served for supplying necessaries to the few workers who were then visiting roscoff; but as the number of these kept gradually increasing, it became necessary to think of enlarging the station, and the purchase of a piece of property was decided upon. since then, mr. lacaze duthiers has done nothing but develop and transform this first acquisition. a large house, which was fitted up in , formed the new laboratory. this was built in a large garden situated nearly at the edge of the sea. we say _nearly_, as the garden in fact was separated from the sea by a small road. the plan in fig. shows that this road makes an angle; but formerly it was straight, and passed over the terrace which now borders upon the fish pond. how many measures, voyages, and endless discussions, and how much paper and ink, it has taken to get this road ceded to the laboratory! finally, after months of contest, victory rewarded mr. duthiers's tenacity, and he was then able to begin the construction of a pond and aquarium. all this was not done at once. [illustration: fig. .--plan of the roscoff laboratory.] another capital improvement was made in . the public school adjoining the establishment was ceded to it, the separating walls fell, the school became a laboratory, the class rooms were replaced by halls for research, and now no trace of the former separation can be seen--so uniform a whole does the laboratory form. no one knows what patience it required to form, piecemeal as it were, so vast an establishment, and one whose every part so completely harmonizes. during the same year a park, one acre in area, was laid out on the beach opposite the laboratory. this is daily covered by the sea, and forms a preserve in which animals multiply, and which, during the inclement season, when distant excursions are impossible, permits of satisfying the demands that come from every quarter. all, however, is not finished. last year a small piece of land was purchased for the installation of hydraulic apparatus for filling the aquarium. this acquisition was likewise indispensable, in order to prevent buildings from being erected upon the land and shutting off the light from the work rooms opposite. alas, here we find our enemy again--the little road! negotiations have been going on for eighteen months with the common council, and, what is worse, with the army engineers, concerning the cession of this wretched footpath. the reader now knows the principal phases of the increases and improvements through which the roscoff station has passed. if, with the plan before his eyes, he will follow us, we will together visit the various parts of the laboratory. the principal entrance is situated upon the city square, one of the sides of which is formed by the buildings of the station. we first enter a large and beautiful garden ornamented with large trees and magnificent flowers which the mild and damp climate of roscoff makes bloom in profusion. we next enter a work room which is designed for those pupils who, doing no special work, come to roscoff in order to study from nature what has been taught them theoretically in the lecture courses of schools, etc. there is room here for nine pupils, to each of whom the laboratory offers two tables, with tanks, bowls, reagents, microscopes, and instruments of all kinds for cabinet study, as well as for researches upon animals on the beach. here the pupils are in presence of each other, and so the explanations given by the laboratory assistants are taken advantage of by all. at the end of this room, on turning to the left, we find two large apartments--the library and museum. here have been gradually collected together the principal works concerning the fauna of roscoff and the english channel, maps and plans useful for consultation, numerous memoirs, and a small literary library. the scientific collection contains the greater portion of the animals that inhabit the vicinity of roscoff. to every specimen is affixed a label giving a host of data concerning the habits, method of capture, and the various biological conditions special to it. in a few years, when the data thus accumulated every season by naturalists have been brought together, we shall have a most valuable collection of facts concerning the fauna of the coast of france. two store rooms at the end of these apartments occupy the center of the laboratory, and are thus more easy of access from the work rooms, and the objects that each one desires can be quickly got for him. [illustration: fig. .--interior of one of the stalls for study.] after the store rooms comes what was formerly the class room for boys, and which has space for three workers, and then the former girls' class room, which has space for eight more. let us stop for a moment in this large room, which is divided up into eight stalls, each of which is put at the disposal of some naturalist who is making original researches. fig. represents one of these, and all the rest are like it. three tables are provided, the space between which is occupied by the worker. of these, one is reserved for the tanks that contain the animals, another, placed opposite a window giving a good light, supports the optical apparatus, and the last is occupied by delicate objects, drawings, notes, etc., and is, after a manner, the worker's desk. some shelving, some pegs, and a small cupboard complete the stall. it is unnecessary to say that the laboratory furnishes gratuitously to those who are making researches everything that can be of service to them. four of these stalls are situated to the north, with a view of the sea, and the other four overlook the garden. they are separated from each other by a simple partition, and all open on a wide central corridor that leads to the aquarium. before reaching the latter we find two offices that face each other, one of them for the lecturer and the other for the preparator. these rooms, as far as their arrangement is concerned, are identical with the stalls of the workers. the laboratory, then, is capable of receiving twenty-three workers at a time, and of offering them every facility for researches. [illustration: fig. .--general view of the roscoff laboratory.] the aquarium is an immense room, ft. in length by in width, glazed at the two sides. it is at present occupied only by temporary tanks that are to be replaced before long by twenty large ones of gallons capacity, and two oval basins of from to gallons capacity, constructed after the model of the one that is giving so good results at banyuls. at the extremity of the aquarium there is a store room containing trawls, nets of all kinds, and mops, for the capture of animals. here too is kept the rigging of the two laboratory boats, the dentale and laura. above the store room is located the director's work room. a wide terrace separates the aquarium from the pond. this latter is yards long by wide. thanks to a system of sluice valves, it is filled during high tide, and the water is shut in at low tide, thus permitting of having a supply of living animals in boxes and baskets until the resources of the laboratory permit of a more improved arrangement. this basin is shown in fig. . it is at the north side of the laboratory as seen from the beach. here too we see the aquarium, the garden, and a portion of the shore that serves as a post for the station boats. we must not, in passing, fail to mention the extreme convenience that the proximity of the aquarium work room to the pond and sea offers to the student. this entire collection of halls, constituting the scientific portion of the laboratory, occupies the ground floor. the first and second stories are occupied by sleeping apartments, fourteen in number. these, without being luxurious, are sufficiently comfortable, and offer the great advantage that they are very near the work rooms, thus permitting of observing, at leisure, and at any hour of the day or night, the animals under study. everything is absolutely free at the laboratory. the work rooms, instruments, reagents, boats, dwelling apartments, etc., are put at the disposal of all with an equal liberality; and this absence of distinction between rich or poor, frenchmen or foreigners, is the source of a charming cordiality and good will among the workers. shall we speak, too, of the richness of the roscoff fauna? this has become proverbial among zoologists, as can be attested by the of them who have worked at the laboratory. the very numerous and remarkable memoirs that have been prepared here are to be found recorded in the fourteen volumes of the _archives de zoologie experimentale_ founded by mr. lacaze duthiers. it only remains to express our hope that the aquarium may be soon finished; but before this is done it will be necessary to get possession of that unfortunate little road. after this final victory, mr. duthiers in his turn will be able, amid his pupils, to enjoy all those advantages of his work which he has until now offered to others, but from which he himself has gained no benefit.--_la nature._ * * * * * the murÆnÆ at the berlin aquarium. of all fish, eels are probably the most interesting, as the least is known of them. electricians are now examining the animal source of electricity in the electric eel (gymnotus electricus); zoologists are still searching for the solution of the problem of the generation of eels, of which no more is known than that the young eels are not born alive; and numerous fishing societies are now studying the important question of raising eels in ponds, lakes, etc., that are not connected with the sea. [illustration: the murÆnÆ at the berlin aquarium.] the annexed cut, taken from the _illustrirte zeitung_, is a copy of a drawing by muetzel, and represents a group of mediterranean murænæ (muræna helena). this fish attains a length of from ft. to ft., and has a smooth, scaleless body of a dark color, on which large light-yellow spots appear, which give the fish a very peculiar appearance. the pectoral fin is missing, but it has the dorsal and anal fins, which it uses with great ability. its head is pointed, and its jaws are provided with extraordinarily sharp teeth, which are inclined toward the rear; and at each side of the head it is provided with a gill. the nostrils are on the upper side of the snout, and a second, tubular, pair of nostrils is located near the eyes. the bright eyes have a fierce expression, which makes the fish appear very much like a snake. these fish are ravenous, and devour crabs, snails, worms, and fishes, and if they have no other food, bite off the tails of their brethren. they are caught in eel baskets or cages, and by means of hooks; but they are rather dangerous to handle, as they attack the fishermen and injure them severely. since the times of the ancients, murænæ have been prized very highly on account of their savory flesh. the romans were great experts at feeding these fish, vidius pollio being the master of them all, as he made a practice of feeding his murænæ with the flesh of slaves sentenced to death. pliny states that at cæsar's triumphal entry hirius furnished six thousand murænæ. slaves were frequently driven into the ponds, and were immediately attacked by the voracious fishes, and killed in a very short time. * * * * * metamorphoses of arctic insects. in the chapter entitled "das insektenleben in arktischen ländern," which dr. christopher aurivillius contributes to the account of a.e. nordenskiöld's arctic investigations, published this year in leipzig,[ ] the author says: "the question of the mode of life of insects and of its relation to their environment in the extreme north is one of especial interest. knowing, as we do, that any insect in the extreme north has at the most not more than from four to six weeks in each year for its development, we wonder how certain species can pass through their metamorphosis in so short a period. r. mclachlan adverts, in his work upon the insects of grinnell land, to the difficulties which the shortness of the summer appears to put in the way of the development of the insects, and expresses the belief that the metamorphosis which we are accustomed here to see passed through in one summer there requires several summers. the correctness of this supposition has been completely shown by the interesting observations which g. sandberg has made upon species of lepidoptera in south varanger, at ° ' north latitude. sandberg succeeded in following the development from the egg onward of some species of the extreme north. _oeneis bore_, schn., a purely arctic butterfly, may be taken as an example. this species has never been found outside of arctic regions, and even there occurs only in places of purely arctic stamp. it flies from the middle of june onward, and lays its eggs on different species of grass. the eggs hatch the same summer; the larva hibernates under ground, continues eating and growing the next summer, and does not even then reach its full development, but winters a second time and pupates the following spring. the pupa, which in closely related forms, in regions further to the south, is suspended free in the air upon a blade of grass or like object, is in this case made in the ground, which must be a very advantageous habit is so raw a climate. the imago leaves the pupa after from five or six weeks, an uncommonly long period for a butterfly. in more southern regions the butterfly pupa rests not more than fourteen days in summer. the entire development, then, takes place much more slowly than it does in regions further south. sandberg has shown, then, by this and other observations, that the arctic summer, even at ° n., is not sufficient for the development of many butterflies, but that they make use of two or more summers for it. if then more than one summer is requisite for the metamorphosis of the butterflies, it appears to me still more likely that the humble-bees need more than one summer for their metamorphosis. with us only the developed female lives over from one year to the next; in spring she builds the new nest, lays eggs, and rears the larvæ which develop into the workers, who immediately begin to help in the support of the family; finally, toward autumn, males and females are developed. it seems scarcely credible that all this can take place each summer in the same way in grinnell land, at ° n., especially as the access to food must be more limited than it is with us. the development of the humble-bee colony must surely be quite different there. if it is not surely proved that the humble-bees occur at so high latitudes, one would not, with a knowledge of their mode of life, be inclined to believe that they could live under such conditions. they seem, however, to have one advantage over their relatives in the south. in the arctic regions none of those parasites are found which in other regions lessen their numbers, such as the _conopidæ_ among the flies, the mutillas among the hymenoptera, and others."--_psyche._ [footnote : nordenskiöld, a.e., studien und forschungen veranlasst durch meine reisen im hohen norden. autorisirte ausgabe. leipzig, brockhaus, , + pp., pl., maps, o. il.] * * * * * a year's scientific progress in nervous and mental diseases. [footnote: volunteer report presented to nebraska state medical society, may, , at grand island, neb.] by l.a. merriam, m.d., omaha, neb., professor of the principles and practice of medicine in the university of nebraska college of medicine, lincoln, neb. the records of the nebraska state medical society show that the only report of progress on nervous and mental diseases ever made in the history of the society (sixteen years) was made by the writer last year; and expecting that those appointed to make a report this year would, judging by the history of the past, fail to prepare such a report, i have seen fit to prepare a brief volunteer report of such items of progress as have come to my notice during the last twelve months. i have not been able to learn that any original work has been done in our state during the past year, nor that those having charge of the insane hospital have utilized the material at their command to add to the sum of our knowledge of mental diseases. last year i said: "there is a growing sentiment that many diseases not heretofore regarded as nervous (and perhaps all diseases) are of nervous origin." this truth, that all pathologico-histological changes in the tissues of the body are degenerative in character, and, whether caused by a parasite, a poison, or some unknown influence, are first brought about by or through a changed innervation, is one that is being accepted very largely by the best men in the profession, and the accumulation of facts is increasing rapidly, and the acceptance of this great truth will prove to be little short of revolutionary in its influence on the treatment of the disease. this is the outgrowth of the study of disease from the standpoint of the evolution hypothesis. derangements of function precede abnormalities of structure; hence the innervation must be at fault before the organ fails. hence the art of healing should aim at grappling with the neuroses first, for the local trophic changes, perverted secretions, and structural abnormalities are the effects or symptoms, not the causes of the disease. dr. j.l. thudicum has studied the chemical constitution of the brain, and he holds that, "when the normal composition of the brain shall be known to the uttermost item, then pathology can begin its search for abnormal compounds or derangements of quantities." the great diseases of the brain and spine, such as general paralysis, acute and chronic mania, and others, the author believes will all be shown to be connected with special chemical changes in neuroplasm, and that a knowledge of the composition and properties of this tissue and of its constituents will materially aid in devising modes of radical treatment in cases in which, at present, only tentative symptomatic measures are taken. the whole drift of recent brain inquiry sets toward the notion that the brain always acts as a whole, and that no part of it can be discharging without altering the tensions of all the other parts; for an identical feeling cannot recur, for it would have to recur in an unmodified brain, which is an impossibility, since the structure of the brain itself is continually growing different under the pressure of experience. insanity is a disease of the most highly differentiated parts of the nervous system, in which the psychical functions, as thought, feeling, and volition, are seriously impaired, revealing itself in a series of mental phenomena. institutions for the insane were at first founded for public relief, and not to benefit the insane; but this idea has changed in the past, and there is a growing feeling that a natural and domestic abode, adapted to the varying severity of the different degrees of insanity, should be the place for the insane, with some reference to their wants and necessities, and that many patients (not all) could be better treated in a domestic or segregate asylum than in the prison-like structures that so often exist, and that the asylum should be as much house-like and home-like in character as the nature of the insanity would permit; while exercise and feeding are accounted as among the best remedies in some cases of insanity, particularly in acute mania. the new disease called morbus thomsenii, of which i wrote in my report last year, has been carefully studied by several men of eminence, and the following conclusions have been reached as to its pathology: the weight of the evidence seems to prove that it is of a neuropathic rather than a myopathic nature, and that it depends on an exaggerated activity of the nervous apparatus which produces muscular tone, and that it has much analogy to the muscular phenomena of hysterical hypnosis, the genesis of which is precisely explained by a functional hyperactivity of the nervous centers of muscular activity. until quite recently it was supposed that the rhythmical action of the heart was entirely due to the periodical and orderly discharge of motor nerve force in the nerve ganglia which are scattered through the organ; but recent physiological observations, more especially the brilliant researches of graskell, seem to show that the influence of the cardiac ganglia is not indispensable, and that the muscular fiber itself, in some of the lower animals, at all events possesses the power of rhythmical contraction. several valuable additions to our knowledge of the anatomy of the nervous system have been made by huschke, exner, fuchs, and tuczek. tuczek and fuchs have confirmed the discoveries of exner, that there are no medullated nerve fibers in the convolutions of the infant, and flechzig has developed this law, that "medullated nerve fibers appear first in the region of the pyramidal tracts and corona radiata, and extend from them to the convolutions and periphery of the brain," being practically completed about the eighth year. this fact is of practical importance in nervous and mental diseases, since it is becoming an admitted truth that the histological changes in disease follow in an inverse order the developmental processes taking place in the embryo. hence the recent physiological division of the nervous system by dr. hughlings jackson into highest, middle, and lowest centers, and the evolution of the cerebro-spinal functions from the most automatic to the least automatic, from the most simple to the most complex, from the most organized to the least organized. in the recognition of this division we have the promise of a steadier and more scientific advance, both in the physiology and in the pathology of the nervous system. mr. victor horsley has recently demonstrated the existence of true sensory nerves supplying the nerve trunks of nervi-nervorum. prof. hamilton, of aberdeen, claims that the corpus callosum is not a commissure, but the decussation of cortical fibers on their way down to enter the internal and external capsules of the opposite side. profs. burt g. wilder, of ithaca, and t. jefrie parker, of new zealand institute, have proposed a new nomenclature for macroscopic encephalic anatomy, which, while seemingly imperfect in many respects, has, at least, the merit of stimulating thought, and has given an impulse to a reform which will not cease until something has been actually accomplished in this direction. the object being to substitute for many of the polynomial terms, technical and vernacular, now in use, technical names which are brief and consist of a single word. this has already been adopted by several neurologists, of whom we may mention spitzka, ramsey, wright, and h.t. osborn. luys holds that the brain, as a whole, changes its position in the cranial cavity according to different attitudes of the body, the free spaces on the upper side being occupied by cerebro-spinal fluid, which, obeying the laws of gravity, is displaced by the heavier brain substance in different positions of the body. luys claims that momentary vertigo, often produced by changing from a horizontal to a vertical position, seasickness, pain in movement in cases of meningitis, epileptic attacks at night, etc., may be by this explained. these views of luys are accepted as true, but to a less extent than taught by luys. the prevalent idea that a lesion of one hemisphere produces a paralysis upon the opposite side of the body alone is no longer tenable, for each hemisphere is connected with both sides of the body by motor tracts, the larger of the motor tracts decussating and the smaller not decussating in the medulla. hence a lesion of one hemisphere produces paralysis upon the opposite side of the body. it has recently been established that a lesion of one hemisphere in the visual area produces, not blindness in the opposite eye, as was formerly supposed, but a certain degree of blindness in both eyes, that in the opposite eye being greater in extent than that in the eye of the same side. analogy would indicate that other sensations follow the same law, hence the probability is that all the sensations from one side of the body do not pass to the parietal cortex of the opposite side, but that, while the majority so pass, a portion go up to the cortex of the same side from which they come. dr. hammond says that the chief feature of the new siberian disease called miryachit is, that the victims are obliged to mimic and execute movements that they see in others, and which motions they are ordered to execute. dr. beard, in june, , observed the same condition when traveling among the maine hunters, near moosehead lake. these men are called jumpers, or jumping frenchmen. those subject to it start when any sudden noise reaches the ears. it appears to be due to the fact that motor impulse is excited by perceptions without the necessary concurrence of the volition of the individual to cause the discharge, and are analogous to epileptiform paroxysms due to reflex action. the term spiritualism has come to signify more than has usually been ascribed to it, for some recent authors are now using the term to denote a neurosis or nervous affection peculiar to that class of people who claim to be able to commune with the spirits of the dead. evidence obtained from clinical observations has tended of late to locate the pathological lesions of chorea in the cerebral cortex. dr. godlee's operation of removing a tumor from the brain marks an important step in cerebral localization, and cerebral surgery bids fair to take a prominent place in the treatment of mental diseases. wernicke has observed that the size of the occipital lobes is in proportion to the size of the optic tracts, and that the occipital lobes are the centers of vision. hughlings jackson has observed that limited and general convulsions were often produced by disease in the cortex of the so-called motor convolutions. the sense of smell has been localized by munk in the gyri hippocampi, while the center of hearing has been demonstrated to be in the temporal lobes. the center for the muscles of the face and tongue is in the inferior part of the central convolution; that for the arm, in the central part; that for the leg, in the superior part of the same convolution; the center for the muscles and for general sensibility, in the angular gyrus; and the center for the muscles of the trunk, in the frontal lobes. in pure motor aphasia the lesion is in the posterior part of the left third frontal convolution; in cases of pure sensory aphasia, the lesion is in the left first temporal convolution. the relation of the cerebrum to cutaneous diseases has been studied much of late, and it is now held that the cutaneous eruptions are mainly due to the degree of inhibiting effect exerted upon the vaso-motor center. the relation of the spinal cord to skin eruptions has been more thoroughly investigated and more abundant evidence supplied to demonstrate the influence degeneration of the spinal cord has in causing skin diseases, notably zoster, urticaria, and eczema. this rheumatism, pneumonia, diabetes, and some kidney diseases and liver affections are often the result of persistent nervous disturbance is now held. that a high temperature (the highest recorded) has resulted from injuries of the spinal cord, and where the influence of microzymes is excluded, is not a matter of question. in one instance, the temperature reached ° f., and remained for seven weeks between ° and ° f. the patient was a lady; the result was recovery. hence it cannot be fever which kills or produces rapid softening of the heart and other organs in fatal cases of typhoid. fever, so far as it consists in elevation of temperature, can be a simple neurosis. many other items of progress might be presented did time permit, particularly in the treatment of nervous affections, but this i leave for another occasion. * * * * * scaring the baby out. dr. grangier, surgeon in the french army, writes from algeria: "a few days after the occupation of brizerte, when the military authorities had forbidden, under the severest penalties, the discharge of firearms within the town, the whole garrison was awakened at three o'clock one morning by the tremendous explosion of a heavily loaded gun in the neighborhood of the ramparts; a guard of soldiers rushed into the house from whence the sound had come, and found a woman lying on the floor with a newly born babe between her thighs. the father of the child stood over his wife with the smoking musket still in his hand, but his intentions in firing the gun had been wholly medical, and not hostile to the french troops. the husband discovered that his wife had been in labor for thirty-six hours. labor was slow and the contractions weak and far apart. he had thought it advisable to provoke speedy contraction, and, following the algerian custom to _scare the baby_ out, he had fired the musket near his wife's ear; instantanously the accouchement was terminated. after being imprisoned twenty-four hours, the arab was released."--_cincinnati lancet._ * * * * * "elastic limit" in metal. the _engineering and mining journal_ raises the question whether steel, which is becoming so popular a substitute for wrought iron, will, when it is subjected to continuous strain in suspension bridges and other similar structures, do as well as iron has proved that it can. recent tests of sections from the cables at fairmount park, philadelphia, and at niagara falls show that long use has not materially changed the structure. the _journal_ says: "it is a serious question, and one which time only can completely answer, whether steel structures will prove as uniformly and permanently reliable as wrought iron has proved itself to be. in other words, whether the fibrous texture of wrought iron can be equaled in this respect by the granulated texture of steel or ingot iron. in this connection it is interesting to note that the fibrous texture referred to is imparted to wrought iron by the presence in it of a small proportion of slag from the puddling furnace, and that this can be secured in the bessemer converter also if desired. the so-called _klein-bessemerei,_ carried on at avesta in sweden for several years past, produces an exclusively soft, fibrous iron by the simple device of pouring slag and iron together into the ingot mould. this requires however a very small charge (usually not more than half a ton), and a direct pouring from the converter, without the intervention of a ladle, which would chill the slag." the effect of the introduction of slag would seem to be to retrace the steps usually taken in producing steel, viz., to separate the iron from its impurities, and then to add definite quantities of carbon and such other ingredients as are found to neutralize the effects of certain impurities not fully removed. the most intelligent engineers, after ascertaining by exhaustive physical tests what they need, present their "requirements" to the iron and steel makers, whose practical experience and science guide them in the protracted metallurgical experiments necessary to find the exact process required. the engineer verifies the product by further tests, and by practical use may find that his "requirement" needs further modifications. as a result of all this care, some degree of certainty is secured as to what the material may be expected to do. no doubt the chemical composition of the slag used at avesta was known and met some equally well known want in the iron, and thus the result arrived at was one which had been definitely and intelligently sought. an important factor in selecting material for the cables of suspension bridges is its _true elastic limit_. by this term we mean the percentage of the total strength of the material which it can exert continuously without losing its resilience, i.e., its power to resume its former shape and position when stress is removed. now, in the case particularly of steel wire as commonly furnished in spiral coils, the curve put into the wire in the process of manufacture seriously diminishes this available sustaining power. for it is evident that it would be unsafe to subject these cables at any time to a stress beyond their elastic limit. if, e.g., a snowstorm or a great crowd of people should load a bridge beyond this limit, when the extra weight was removed the cables could not bring the bridge back to its normal place, and the result would be a permanent flattening and weakening of the arch. by a process invented and patented by col. paine, the wire in the new york and brooklyn bridge was furnished _straight_ instead of curved. now, if a short piece of common steel wire is taken from the coil, and pulled toward a straight position, and then released, it springs back into its former curve; but if a short piece of the straight-furnished wire that was put into this bridge is bent, and then released, it springs back toward its straight position. it is easy to see that if a curved wire is pulled straight, there must occur a distention of the particles on the inside of the curve and a compression of those on the outside. the inside is in fact strained past its elastic limit before _any_ stress comes upon the outside. hence, after the wire has been pulled straight, the elastic limit of only a portion of it can be taken into the account in calculating the load that can safely be put upon it. in the case of curved steel wire pulled straight, its ultimate strength was found to be only about per cent. that of similar wire furnished straight by this process. the superior ductility of iron wire in some measure compensates for the distention of the particles on the inside of the curve, and that is a reason why it has heretofore been used for suspension bridges. but with straight steel wire there is no such distention, and its _entire elastic limit_ is available. this elastic limit is per cent. of the ultimate strength, and, besides, that ultimate strength is per cent. greater than that of similar curved wire. thus if we have a curved steel wire large enough to sustain , lb. without breaking, a similar straight wire, such as those in this bridge, will hold up , lb., and per cent. of this , lb = lb. the elastic limit of curved wire has never been determined, since any stress that will cause it to reach a straight line is beyond the elastic limit of the inside of its sectional area. that of curved iron wire has been estimated at per cent. of its ultimate strength, which is about half the ultimate strength of curved steel wire; that is, it would be unsafe to put more than per cent. of lb.--or lb.--upon a curved iron wire when a _straight_ steel one can sustain lb. without injury. in the new york and brooklyn bridge the cost of a sufficient amount of such iron wire as is used in all other suspension bridges would have been some $ , greater than that of the straight steel wire which was used. at five per cent., this effects an annual saving in interest of $ , . there must, too, be a considerable saving in the current expense for painting and care, to say nothing of the more neat and elegant appearance of the less bulky steel. and as the whole area of the section of these wires is subjected to an even strain that is always far within the elastic limit, there is no danger of a change of structure under that stress. it is highly probable--although col. paine has been too busy to work up the matter--that piano wire made in this straight method could be drawn up to and kept at pitch, without approaching very near the elastic limit. in that case not only would they seldom if ever require tuning, but probably all along the tone would be more satisfactory. and there would not be those exasperating periods when the pitch is not quite perfect, but yet is not far enough out to make it seem worth while to send for a tuner. * * * * * a catalogue, containing brief notices of many important scientific papers heretofore published in the supplement, may be had gratis at this office. * * * * * the scientific american supplement. published weekly. terms of subscription, $ a year. sent by mail, postage prepaid, to subscribers in any part of the united states or canada. six dollars a year, sent, prepaid, to any foreign country. all the back numbers of the supplement, from the commencement, january , , can be had. price, cents each. all the back volumes of the supplement can likewise be supplied. two volumes are issued yearly. price of each volume, $ . , stitched in paper, or $ . , bound in stiff covers. combined rates--one copy of scientific american and one copy of scientific american supplement, one year, postpaid, $ . . a liberal discount to booksellers, news agents, and canvassers. munn & co., publishers, broadway, new york, n.y. * * * * * patents. in connection with the scientific american, messrs. munn & co. are solicitors of american and foreign patents, have had years' experience, and now have the largest establishment in the world. patents are obtained on the best terms. a special notice is made in the scientific american of all inventions patented through this agency, with the name and residence of the patentee. by the immense circulation thus given, public attention is directed to the merits of the new patent, and sales or introduction often easily effected. any person who has made a new discovery or invention can ascertain, free of charge, whether a patent can probably be obtained, by writing to munn & co. we also send free our hand book about the patent laws, patents, caveats, trade marks, their costs, and how procured. address munn & co., broadway, new york. branch office, cor. f and th sts., washington, d.c. gases h_{ }s and h_{ }o_{ } on limestone._ carbonate sulphureted peroxide of ethylene and of lime. hydrogen. hydrogen. gypsum. its homologues. caco + h s + h o yield (caso .h o) + c h ethylene (gaseous). caco + h s + h o " (caso .h o) + c h caco + h s + h o " (caso .h o) + c h caco + h s + h o " (caso .h o) + c h caco + h s + h o " (caso .h o) + c h boiling point. caco + h s + h o " (caso .h o) + c h -- caco + h s + h o " (caso .h o) + c h °c. caco + h s + h o " (caso .h o) + c h °c. caco + h s + h o " (caso .h o) + c h °c. caco + h s + h o " (caso .h o) + c h °c. caco + h s + h o " (caso .h o) + c h °c. caco + h s + h o " (caso .h o) + c h °c. caco + h s + h o " (caso .h o) + c h °c. caco + h s + h o " (caso .h o) + c h -- it is explained that these effects must have occurred, not at periods of acute volcanic eruptions, but in conditions which maybe, and have been, observed at the present time, wherever there are active solfataras or mud volcanoes at work. descriptions of the action of solfataras by the late sir richard burton and by a british consul in iceland are quoted, and also a paragraph from lyall's "principles of geology," in which he remarks of the mud volcanoes at girgenti (sicily) that _carbureted hydrogen_ is discharged from them, sometimes with great violence, and that they are known to have been casting out water, mixed with mud and _bitumen_, with the same activity as now for the last fifteen centuries. probably at all these solfataras, if the gases traverse limestone, fresh deposits of oil-bearing strata are accumulating, and the same volcanic action has been occurring during many successive geological periods and millions of years; so that it is difficult to conceive limits to the magnitude of the stores of petroleum which may be awaiting discovery in the subterranean depths.[ ] [footnote : professor j. le conte, when presiding recently at the international geological congress at washington, mentioned that in the united states extensive lava floods have been observed, covering areas from , to , square miles in extent and from , to , feet deep. we have similar lava flows and ashes in the north of england, in scotland, and in ireland, varying from , to , feet in depth. in the lake district they are nearly , feet deep. solfataras are active during the intermediate, or so-called "dormant," periods which occur between acute volcanic eruptions.] gypsum may also be an indication of oil-bearing strata, for the substitution in limestone of sulphuric for carbonic acid can only be accounted for by the action of these hot sulphurous gases. gypsum is found extensively in the petroleum districts of the united states, and it underlies the rock salt beds at middlesboro, where, on being pierced, it has given passage to oil gas, which issues abundantly, mixed with brine, from a great depth. iii. besides the space occupied by "natural gas," which is very extensive, , million gallons of petroleum have been raised in america since , and that quantity must have occupied more than , , cubic yards, a space equal to a subterranean cavern yards wide by feet deep, and miles in length, and it is suggested that beds of "porous sandstone" could hardly have contained so much; while vast receptacles may exist, carved by volcanic water out of former beds of rock salt adjoining the limestone, which would account for the brine that usually accompanies petroleum. it is further suggested that when no such vacant spaces were available, the hydrocarbon vapors would be absorbed into, and condensed in, contiguous clays and shales, and perhaps also in beds of coal, only partially consolidated at the time. there is an extensive bituminous limestone formation in persia, containing per cent. of bitumen, and the theory elaborated in the paper would account for bitumen and oil having been found in canada and tennessee embedded in limestone, which fact is cited by mr. peckham as favoring his belief that some petroleums are a "product of the decomposition of animal remains." above all, this theory accounts for the many varieties in the chemical composition of paraffin oils in accordance with ordinary operations of nature during successive geological periods.--_chem. news._ * * * * * the colorado desert lake. mr. j.j. mcgillivray, who has been for many years in the united states mineral survey service, has some interesting things to say about the overflow of the colorado desert, which has excited so much comment, and about which so many different stories have been told: "none of the papers, so far as i know," said mr. mcgillivray, "have described with much accuracy or detail the interesting thing which has happened in the colorado desert or have stated how it happened. the colorado desert lies a short distance northwest of the upper end of the gulf of california, and contains not far from , square miles. the colorado river, which has now flooded it, has been flowing along to the east of it, emptying into the gulf of california. the surface of the desert is almost all level and low, some of it below the sea level. some few hundreds of years ago it was a bay making in from the gulf of california, and then served as the outlet of the colorado river. but the river carried a good deal of sediment, and in time made a bar, which slowly and surely shut off the sea on the south, leaving only a narrow channel for the escape of the river, which cut its way out, probably at some time when it was not carrying much sediment. then the current became more rapid and cut its way back into the land, and, in doing this, did not necessarily choose the lowest place, but rather the place where the formation of the land was soft and easily cut away by the action of the water. "while the river was cutting its way back it was, of course, carrying more or less sediment, and this was left along the banks, building them all the time higher, and confining the river more securely in its bounds. that is the colorado river as we have known it ever since its discovery. meantime, the water left in the shallow lake, cut off from the flow of the river, gradually evaporated--a thing that would take but a few years in that country, where the heat is intense and the humidity very low. that left somewhere about , miles of desert land, covered with a deposit of salt from the sea water which had evaporated, and most of it below the level of the sea. that is the colorado desert as it has been known since its discovery. "then, last spring, came the overflow which has brought about the present state of affairs. the river was high and carrying an enormous amount of sediment in proportion to the quantity of water. this gradually filled up the bed of the stream and caused it to overflow its banks, breaking through into the dry lake where it had formerly flowed. the fact that the water is salt, which excited much comment at the time the overflow was first discovered, is, of course, due to the fact that the salt in the sea water which evaporated hundreds of years ago has remained there all the time, and is now once more in solution. "the desert will, no doubt, continue to be a lake and the outlet of the river unless the breaks in the banks of the river are dammed by artificial means, which seems hardly possible, as the river has been flowing through the break in the stream feet wide, four feet deep, and flowing at a velocity of five feet a second. "it is an interesting fact to note that the military survey made in went over this ground and predicted the very thing which has now happened. the flooding of the desert will be a good thing for the surrounding country, for it does away with a large tract of absolutely useless land, so barren that it is impossible to raise there what the man in texas said they mostly raised in his town, and it will increase the humidity of the surrounding territory. nature has done with this piece of waste land what it has often been proposed to do by private enterprise or by public appropriation. congress has often been asked to make an appropriation for that purpose." mr. mcgillivray had also some interesting things to say about death valley, which he surveyed. "it has been called a _terra incognita_ and a place where no human being could live. well, it is bad enough, but perhaps not quite so bad as that. the great trouble is the scarcity of water and the intense heat. but many prospecting parties go there looking for veins of ore and to take out borax. the richest borax mines in the world are found there. the valley is about miles long by miles wide. the lowest point is near the center, where it is about ft. below the level of the sea. just miles west of this central point is telescope peak, , ft. above the sea, and miles east is mt. le count, in the funeral mountains, , ft. high. the valley runs almost due north and south, which is one reason for the extreme heat. the only stream of water in or near the valley flows into its upper end and forms a marsh in the bed of the valley. this marsh gives out a horrible odor of sulphureted hydrogen, the gas which makes a rotten egg so offensive. where the water of this stream comes from is not very definitely known, but in my opinion it comes from owen's lake, beyond the telescope mountains to the west, flowing down into the valley by some subterranean passage. the same impurities found in the stream are also found in the lake, where the water is so saturated with salt, boracic acid, etc., that one can no more sink in it than in the water of the great salt lake; and i found it so saturated that after swimming in it a little while the skin all over my body was gnawed and made very sore by the acids. another reason why i think the water of the stream enters the valley by some fixed subterranean source is the fact that, no matter what the season, the flow from the springs that feed the marsh is always exactly the same. "the heat there is intense. a man cannot go an hour without water without becoming insane. while we were surveying there, we had the same wooden cased thermometer that is used by the signal service. it was hung in the shade on the side of our shed, with the only stream in the country flowing directly under it, and it repeatedly registered °; and for hours in , when i was surveying there, the thermometer never once went below °."--_boston herald._ * * * * * hemlock and parsley. by w.w. bailey. the study of the order umbelliferæ presents peculiar difficulties to the beginner, for the flowers are uniformly small and strikingly similar throughout the large and very natural group. the family distinctions or features are quite pronounced and unmistakable, and it is the determination of the genera which presents obstacles--serious, indeed, but not insurmountable. "by their fruits shall ye know them." the umbelliferæ, as we see them here, are herbaceous, with hollow, often striated stems, usually more or less divided leaves, and no stipules. occasionally we meet a genus, like eryngium or hydrocotyle, with leaves merely toothed or lobed. the petioles are expanded into sheaths; hence the leaves wither on the stem. the flowers are usually arranged in simple or compound umbels, and the main and subordinate clusters may or may not be provided with involucres and involucels. to this mode of arrangement there are exceptions. in marsh-penny-wort (hydrocotyle) the umbels are in the axils of the leaves, and scarcely noticeable; in eryngium and sanicula they are in heads. the calyx is coherent with the two-celled ovary, and the border is either obsolete or much reduced. there are five petals inserted on the ovary, and external to a fleshy disk. each petal has its tip inflexed, giving it an obcordate appearance. the common colors of the corolla are white, yellow, or some shade of blue. alternating with the petals, and inserted with them, are the five stamens. the fruit, upon which so much stress is laid in the study of the family, is compound, of two similar parts or carpels, each of which contains a seed. in ripening the parts separate, and hang divergent from a hair-like prolongation of the receptacle known as the gynophore. each half fruit (mericarp) is tipped by a persistent style, and marked by vertical ribs, between or under which lie, in many genera, the oil tubes or vittæ. these are channels containing aromatic and volatile oil. in examination the botanist makes delicate cross sections of these fruits under a dissecting microscope, and by the shape of the fruit and seed within, and by the number and position of the ribs and oil tubes, is able to locate the genus. it, of course, requires skill and experience to do this, but any commonly intelligent class can learn the process. it goes without saying, and as a corollary to what has already been stated, that these plants should always be collected in full fruit; the flowers are comparatively unimportant. any botanist would be justified in declining to name one of the family not in fruit. an attempt would often be mere guesswork. in this family is found the poison hemlock (conium) used by the ancient greeks for the elimination of politicians. it is a powerful poison. the whole plant has a curious mousy odor. it is of european origin. our water hemlock is equally poisonous, and much more common. it is the _cicuta maculata_ of the swamps--a tall, coarse plant which has given rise to many sad accidents. _Æthusa cynapium_, another poisonous plant, known as "fool's parsley," is not uncommon, and certainly looks much like parsley. this only goes to show how difficult it is for any but the trained botanist to detect differences in this group of plants. side by side may be growing two specimens, to the ordinary eye precisely alike, yet the one will be innocent and the other poisonous. the drug asafetida is a product of this order. all the plants appear to "form three different principles: the first, a watery acid matter; the second, a gum-resinous milky substance; and the third, an aromatic, oily secretion. when the first of these predominates they are poisonous; the second in excess converts them into stimulants; the absence of the two renders them useful as esculents; the third causes them to be pleasant condiments." so that besides the noxious plants there is a long range of useful vegetables, as parsnips, parsley, carrots, fennel, dill, anise, caraway, cummin, coriander, and celery. the last, in its wild state, is said to be pernicious, but etiolation changes the products and renders them harmless. the flowers of all are too minute to be individually pretty, but every one knows how charming are the umbels of our wild carrot, resembling as they do the choicest old lace. frequently the carrot has one central maroon colored floret. though most of the plants are herbs, dr. welwitsch found in africa a tree-like one, with a stem one to two feet thick, much prized by the natives for its medicinal properties, and also valuable for its timber. in kamschatka also they assume a sub-arboreous type, as well as on the steppes of afghanistan. as mistakes often occur by confounding the roots of umbelliferæ with those of horse radish or other esculents, it is well, when in doubt, to send the plants, _always in fruit_, if possible, for identification. none of them are poisonous to the touch--at least to ordinary people. cases of rather doubtful authenticity are reported from time to time of injury from the handling of wild carrot. we have always suspected the proximity of poison ivy; still, it is unwise to dogmatize on such matters. some people cannot eat strawberries--more's the pity!--while the rest of us get along with them very happily. lately the _primula obconica_ has acquired an evil reputation as an irritant, so there is no telling what may not happen with certain constitutions. difficult as is the study of umbelliferæ, it becomes fascinating on acquaintance. to hunt up a plant and name it by so scientific a process brings to the student a sufficient reward.--_american naturalist._ * * * * * the eremuri. [illustration: eremurus himalaicus. (flowers white.)] it has often been a matter of astonishment to me that eremuri are not more frequently seen in our gardens. there are certainly very few plants which have a statelier or more handsome appearance during the summer months. both in point of brightness of color and their general habit and manner of growth they are very much to be recommended. for some reason or other they have the character of being difficult plants, but they do not deserve it at all, and a very slight attention to their requirements is enough to ensure success. they can stand a good many degrees of frost, and they ask for little more than a soil which has been deeply worked and well enriched with old rotten manure. give them this, and they are certain to be contented with it, and the cultivator will be well rewarded for his pains. only one thing should perhaps be added by way of precaution. if an eremurus appears too soon above ground, it is well just to cover it over with loose litter of some sort, so that it may not be nipped by spring frosts; and one experienced grower has said that it answers to lift them after blossoming, and to keep them out of the ground for a few weeks, so that they may be sufficiently retarded. but i have not yet been able to try this plan myself, and i do not speak from experience about it. my favorite is eremurus bungei, which i think is one of the handsomest plants i have in my garden. the clear yellow color of the blossom is so very good, and i like the foliage also; but of course it is not the most imposing by any means and if height and stateliness are especially regarded, e. robustus or e. robustus nobilis would carry off the palm. this commonly rises to the height of eight or nine feet above the ground, and on one occasion i have known it to be greatly in excess even of that; but such an elevation cannot be attained for more than a single year, and it afterward is contented with more moderate efforts. e. himalaicus is of the purest possible white, and the spike is very much to be admired when it is seen at its best. it can be very easily raised from seed, but a good deal of patience is needed before its full glory has come. e. olgæ is the last of all, and it shows by its arrival that summer is hastening on. it is of a peach-colored hue, and very pretty indeed. altogether it is a pity that eremuri are not more commonly grown. i think they are certain to give great satisfaction, if only a moderate degree of attention and care be bestowed upon them.--_h. ewbank, in the gardeners' magazine._ * * * * * raphides, the cause of the acridity of certain plants. by r.a. weber, ph.d. at the last meeting of the american association for the advancement of science, prof. w.r. lazenby reported his studies on the occurrence of crystals in plants. in this report he expressed the opinion that the acridity of the indian turnip was due to the presence of these crystals or raphides. this opinion was opposed by prof. burrill and other eminent botanists, who claimed that other plants, as the fuchsia, are not at all acrid, although they contain raphides as plentifully as the indian turnip. here the matter was allowed to rest. the united states dispensatory and other works on pharmacy ascribe the acridity of the indian turnip to an acrid, extremely volatile principle insoluble in water, and alcohol, but soluble in ether. heating and drying the bulbs dissipates the volatiles principle, and the acridity is destroyed. at a recent meeting of ohio state microscopical society this subject was again brought up for discussion. it was thought by some that the raphides in the different plants might vary in chemical composition, and thus the difference in their action be accounted for. this question the writer volunteered to answer. accordingly, four plants containing raphides were selected, two of which, the _calla cassia_ and indian turnip, were highly acrid, and two, the _fuchsia_ and _tradescantia_, or wandering jew, were perfectly bland to the taste. a portion of each plant was crushed in a mortar, water or dilute alcohol was added, the mixture was stirred thoroughly and thrown upon a fine sieve. by repeated washing with water and decanting a sufficient amount of the crystals was obtained for examination. from the calla the crystals were readily secured by this means in a comparatively pure state. in the case of the indian turnip the crystals were contaminated with starch, while the crystals from the fuschia and tradescantia were embedded in an insoluble mucilage from which it was found impossible to separate them. the crystals were all found to be calcium oxalate. having determined the identity in chemical composition of the crystals, it was thought that there might be a difference of form of the crystals in the various plants, from the fact that calcium oxalate crystallizes both in the tetragonal and the monoclinic systems. a laborious microscopic examination, however, showed that this theory also had to be abandoned. the fuchsia and tradescantia contained bundles of raphides of the same form and equally as fine as those of the acrid plants. at this point in the investigation the writer was inclined to the opinion that the acridity of the indian turnip and calla was due to the presence of an acrid principle. since the works on pharmacy claimed that the active principle of the indian turnip was soluble in ether, the investigation was continued in this direction. a large stem of the calla was cut into slices, and the juice expressed by means of a tincture press. the expressed juice was limpid and filled with raphides. a portion of the juice was placed into a cylinder and violently shaken with an equal volume of ether. when the ether had separated a drop was placed upon the tongue. as soon as the effects of the ether had passed away, the same painful acridity was experienced as is produced when the plant itself is tasted. this experiment seemed to corroborate the assumption of an acrid principle soluble in ether. the supernatant ether, however, was slightly turbid in appearance, a fact which was at first ignored. wishing to learn the cause of this turbidity, a drop of the ether was allowed to evaporate on a glass slide. under the microscope the slide was found to be covered with a mass of raphides. a portion of the ether was run through a munktell filter. the filtered ether was clear, entirely free from raphides, and had also lost every trace of its acridity. the same operations were repeated upon the indian turnip with exactly similar results. these experiments show conclusively that the acridity of the indian turnip and calla is due to the raphides of calcium oxalate only. the question of the absence of acridity in the other two plants still remained to be settled. for this purpose some recent twigs and leaves of the fuchsia were subjected to pressure in a tincture press. the expressed juice was not limpid, but thick, mucilaginous and ropy. under the microscope the raphides seemed as plentiful as in the case of the two acrid plants. when diluted with water and shaken with ether, there was no visible turbidity in the supernatant ether, and when a drop of the ether was allowed to evaporate on a glass slide, only a few isolated crystals could be seen. from this it will be seen that in this case the raphides did not separate from the mucilaginous juice to be held in suspension in the ether. a great deal of time and labor were spent in endeavoring to separate the crystals completely from this insoluble mucilage, but without avail. with the tradescantia similar results were obtained. from these experiments the absence of acridity in these two plants, in spite of the abundance of raphides, may readily be explained by the fact that the minute crystals are surrounded with and embedded in an insoluble mucilage, which prevents their free movement into the tongue and surface of the mouth, when portions of the plants are tasted. the reason why the indian turnip loses its acridity on being heated can be explained by the production of starch paste from the abundance of starch present in the bulbs. this starch paste would evidently act in a manner similar to the insoluble mucilage of the other two plants. so also it can readily be seen that when the bulbs of the indian turnip have been dried, the crystals can no longer separate from the hard mass which surrounds them, and consequently can exert no irritant action when the dried bulbs are placed against the tongue.--_jour. am. chem. soc._ * * * * * the whale-headed stork. [illustration: the whale-headed stork--balÆniceps rex.] of all the wonders that inhabit the vast continent of africa, the most singular one is undoubtedly the _balæniceps_, or whale-headed stork. it is of relatively recent discovery, and the first description of it was given by gould in the early part of . it is at present still extremely rare. the paris museum possesses three specimens of it, and the boulogne museum possesses one. these birds always excite the curiosity of the public by their strange aspect. at first sight, says w.p. parker, in his notes upon the osteology of the balæniceps, this bird recalls the boatbill, the heron, and the adjutant. other birds, too, suggest themselves to the mind, such as the pelican, the toucan, the hornbills, and the podarges. the curious form of the bill, in fact, explains this comparison with birds belonging to so different groups, and the balæniceps would merit the name of boatbill equally well with the bird so called, since its bill recalls the small fishing boats that we observe keel upward high and dry on our seashores. this bill is ten inches in length, and four inches in breadth at the base. the upper mandible, which is strongly convex, exhibits upon its median line a slight ridge, which is quite wide at its origin, and then continues to decrease and becomes sensibly depressed as far as to the center of its length, and afterward rises on approaching the anterior extremity, where it terminates in a powerful hook, which seems to form a separate part, as in the albatrosses. throughout its whole extent, up to the beginning of the hook, this mandible presents a strong convexity over its edge, which is turned slightly inward. the lower mandible, which is powerful, and is indented at its point to receive the hook, has a very sharp edge, which, with that of the upper mandible, constitutes a pair of formidable shears. the color of the bill is pale yellow, passing to horn color toward the median ridge, and the whole surface is sprinkled with dark brown blotches. the nostrils are scarcely visible, and are situated in a narrow cleft at the base of the bill, and against the median ridge. the tongue is very small and entirely out of proportion to the vast buccal capacity. this is a character that might assimilate the balæniceps to the pelican. the robust head, the neck, and the throat, are covered with slate-colored feathers verging on green, and not presenting the repulsive aspect of the naked skin of the adjutant. as in the latter, the skin of the throat is capable of being dilated so as to form a voluminous pouch. upon the occiput the feathers are elongated and form a small crest. the body is robust and covered upon the back with slate-colored feathers bordered with ashen gray. upon the breast the feathers are lanceolate, and marked with a dark median stripe. finally, the lower parts, abdomen, sides, and thighs, are pale gray, and the remiges and retrices are black. according to verreaux, the feathers of the under side of the tail are soft and decompounded, but at a distance they only recall the beautiful plumes of the adjutant. the well-developed wings indicate a bird of lofty flight, yet of all the bones of the limbs, anterior as well as posterior, the humerus alone is pneumatized. the strong feet terminate in four very long toes deprived at the interdigital membrane observed in most of the ciconidæ. the claws are powerful and but slightly curved, and that of the median toe is not pectinated as in the herons. the balæniceps is met with only in or near water, but it prefers marshes to rivers. it is abundant upon the banks of the nile only during the hot season which precedes the rains and when the entire interior is dried up. during the rest of the year it inhabits natural ponds and swamps, where the shallow water covers vast areas and presents numerous small islands, of easier access than the banks of the nile, which always slope more or less abruptly into deep water. in such localities it is met with in pairs or in flocks of a hundred or more, seeking its food with tireless energy, or else standing immovable upon one leg, the neck curved and the head resting upon the shoulder. when disturbed, the birds fly just above the surface of the water and stop at a short distance. but when they are startled by the firing of a gun, they ascend to a great height, fly around in a circle and hover for a short time, and then descend upon the loftiest trees, where they remain until the enemy has gone. water turtles, fish, frogs and lizards form the basis of their food. according to petherick, they do not disdain dead animals, whose carcasses they disembowel with their powerful hooked beak. they pass the night upon the ground, upon trees and upon high rocks. as regards nest-making and egg-laying, opinions are most contradictory. according to verreaux, the balæniceps builds its nest of earth, vegetable debris, reeds, grass, etc., upon large trees. the female lays two eggs similar to those of the adjutant. it is quite difficult to reconcile this opinion with that of petherick, who expresses himself as follows: "the balæniceps lays in july and august, and chooses for that purpose the tall reeds or grasses that border the water or some small and slightly elevated island. they dig a hole in the ground, and the female deposits her eggs therein. i have found as many as twelve eggs in the same nest." the whale-headed stork is still so little known that there is nothing in these contradictions that ought to surprise us. authors are no more in accord on the subject of the affinities of this strange bird. gould claims that it presents the closest affinities with the pelican and is the wading type of the pelicanidæ. verreaux believes that its nearest relative is the adjutant, whose ways it has, and that it represents in this group what the boatbill represents in the heron genus. bonaparte regards it as intermediate between the pelican and the boatbill. if we listen to reinhurdt, we must place it, not alongside of the boatbill, but alongside of the african genus scopus. the boatbill, says he, is merely a heron provided with a singular bill, which has but little analogy with that of the balæniceps, and not a true resemblance. the nostrils differ in form and position in those two birds, and in the boatbill there exists beneath the lower mandible a dilatable pouch that we do not find in the balæniceps. an osteological examination leads parker to place the balæniceps near the boatbill, and the present classification is based upon that opinion. the family of ardeidæ is, therefore, divided into five sub-families, the three last of which each comprises a single genus. ardeidæ.--ardeineæ (herons). botaurineæ (bitterns). scopineæ (ombrette). cancomineæ (boatbill). balænicepineæ (whale-headed stork). all the whale-headed storks that have been received up to the present have come from the region of the white nile; but mr. h. johnston, who traveled in congo in , asserts that he met with the bird on the river cunene between benguela and angola, where it was even very common. mr. johnston's assertion has been confirmed by other travelers worthy of credence, but, unfortunately, the best of all confirmations is wanting, and that is a skin of this magnificent wader. we can, therefore, only make a note of mr. johnston's statement, and hope that some traveler may one day enrich our museums with some balæniceps from these regions. the presence of this bird in the southwest of africa is, after all, not impossible; yet there is one question that arises: was the balæniceps observed by mr. johnston of the same species as that of the white nile, or was it a new type that will increase this family, which as yet comprises but one genus and one species--the _balæniceps rex_?--_le naturaliste_. * * * * * the california raisin industry. fresno county, for ten miles about fresno, furnishes the best example of the enormous increase in values which follows the conversion of wheat fields and grazing land into vineyards and orchards. not even riverside can compare with it in the rapid evolution of a great source of wealth which ten years ago was almost unknown. what has transformed fresno from a shambling, dirty resort of cowboys and wheat ranchers into one of the prettiest cities in california is the raisin grape. though nearly all fruits may be grown here, yet this is pre-eminently the home of the raisin industry, and it is the raisin which in a single decade has converted , acres of wheat fields into vineyards. no other crop in california promises such speedy returns or such large profits as the raisin grape, and as the work on the vineyards is not heavy, the result has been a remarkable growth of the infant industry. it is estimated that in this county, which contains , , acres and is nearly as large as massachusetts, there are , acres that may be irrigated and are specially adapted to the grape. as the present crop on about , acres in full bearing is valued at $ , , , some idea may be formed of the revenue that will come to the fresno vineyardists when all this choice valley land is planted and in full bearing. and what makes the prospect of permanent prosperity surer is the fact that nine out of ten new settlers are content with twenty-acre tracts, as one of these is all which a man can well care for, while the income from this little vineyard will average $ , above all expenses, a larger income than is enjoyed by three-quarters of the professional men throughout the country. the raisin industry in california is very young. to be sure, dried grapes have been known since the time of the mission fathers, but the dried mission grape is not a raisin. the men who thirty years ago sent over to europe for the choicest varieties of wine grapes imported among other cuttings the muscatel, the muscat of alexandria, and the feher zagos; the three finest raisin grapes of spain. but the raisin, like the fig, requires skillful treatment, and for years the california grower made no headway. he read all that had been written on the curing of the raisin; several enterprising men went to spain to study the subject at first hand; but despite all this no progress was made. finally several of the pioneer raisin men of fresno cut loose from all precedent, dried their grapes in the simple and natural manner and made a success of it. from that time, not over ten years ago, the growth of the industry has eclipsed that of every other branch of horticulture in the state, and the total value of the product promises soon to exceed the value of the orange crop or the yield of wine and brandy. it required a good deal of nerve for the pioneers of fresno county to spend hundreds of thousands of dollars in bringing water upon what the old settlers regarded as a desert, fit only to grow wheat in a very wet season. in other parts of the state the mission fathers had dug ditches and built aqueducts, so that the settlers who came after them found a well devised water system, which they merely followed. but in fresno no one had ever tried to grow crops by irrigation. when fremont came through there from the mountains he found many wild cattle feeding on the rank grass that grew as high as the head of a man on horseback. the herds of the native californians were almost equally wild. the country was one vast plain which in summer glowed under a sun that was tropical in its intensity. as late as one could travel for a day without seeing a house or any sign of habitation. the country was owned by great cattle growers, who seldom rode over their immense ranches, except at the time of the annual "round-up" of stock. about thirty years ago a number of large wheat growers secured big tracts of land around fresno. at their head was isaac friedlander, known as the wheat king of the pacific coast. friedlander would have transformed this country had not financial ruin overcome him. his place was taken by others, like chapman, easterby, eisen and hughes--men who believed in fruit growing and who had the courage to carry on their operations in the face of repeated failures. the great development of fresno has been due entirely to the colony system, which has also built up most of the flourishing cities of southern california. in the first fresno colony was started by w.s. chapman. he cut up six sections of land into -acre tracts, and brought water from king's river. the colonists represented all classes of people, and though they made many disastrous experiments, with poor varieties of grapes and fruit, still there is no instance of failure recorded, and all who have held on to their land are now in comfortable circumstances. some of the settlers in this colony were san francisco school teachers. they obtained their -acre tracts for $ , and many of them retired on their little vineyards at the end of five or six years. one lady, named miss austen, had the foresight to plant all her property in the best raisin grapes, and for many years drew a larger annual revenue from the property than the whole place cost her. the central colony now has an old established look. the broad avenues are lined with enormous trees; many of the houses are exceedingly beautiful country villas. what a transformation has been wrought here may be appreciated when it is said that families now produce $ , a year on the same land which twenty years ago supported but one family, which had a return of only $ , from wheat. the history of this one colony of six sections of old wheat land is the key to fresno's prosperity. it proves better than columns of argument, or facts or figures, the immense return that careful, patient cultivation may command in this home of the grape. near this colony are a half-dozen others which were established on the same general plan. the most noteworthy is the malaga colony, founded by g.g. briggs, to whom belongs the credit of introducing the raisin grape into fresno. fresno city is the center from which one may drive in three directions and pass through mile after mile of these colonies, all showing signs of the wealth and comfort that raisin making has brought. only toward the west is the land still undeveloped, but another five years promise to see this great tract, stretching away for twenty miles, also laid out in small vineyards and fruit farms. fresno is the natural railroad center of the great san joaquin valley. it is on the main line of the southern pacific and is the most important shipping point between san francisco and los angeles. the new line of the santa fe, which has been surveyed from mojave up through the valley, passes through fresno. then there are three local lines that have the place for a terminus, notably the mountain railway, which climbs into the sierra, and which it is expected will one day connect with the rio grande system and give a new transcontinental line. here are also building round houses and machine shops of the southern pacific company. these, with new factories, packing houses, and other improvements, go far to justify the sanguine expectations of the residents. there has never been a boom in fresno, but a high railroad official recently, in speaking of the growth of the city, said: "fresno in five years will be the second city in california." this prediction he based on the wonderful expansion of its resources in the last decade and the substantial character of all the improvements made. it is a pretty town, with wide, well-paved streets, handsome modern business blocks, and residence avenues that would do credit to any old-settled town of the east. the favorite shade tree is the umbrella tree, which has the graceful, rounded form of the horse chestnut, but with so thick a foliage that its shadow is not dappled with sunlight. above it is an intensely dark green, while viewed from below it is the most delicate shade of pea green. rivaling this in popularity is the pepper tree, also an evergreen, and the magnolia, fan palm, eucalyptus, or australian blue gum, and the poplar. all these trees grow luxuriantly. it has also become the custom in planting a vineyard to put a row of the white adriatic fig trees around the place, and to mark off ten or twenty acre tracts in the same way. the dark green foliage of the fig is a great relief to the eye when the sun beats down on the sandy soil. leading out of fresno are five driveways. the soil makes a natural macadam, which dries in a few hours. throughout the year these roads are in good condition for trotting, and nearly every raisin grower is also an expert in horseflesh, and has a team that will do a mile in less than : . the new race course is one of the finest in the state. toward the west from fresno has recently been opened a magnificent driveway, which promises in a few years to rival the magnolia ave. of riverside. this is called chateau fresno ave. it has two driveways separated by fan palms and magnolias, while along the outer borders are the same trees with other choice tropical growths, that will one day make this avenue well worth traveling many miles to see. this is the private enterprise of mr. theodore kearney, who made a fortune in real estate, and it is noteworthy as an illustration of the large way in which the rich californian goes about any work in which he takes an interest. probably the finest avenue in fresno is the poplar-lined main driveway through the barton vineyard. it is a mile in length, and the trees, fully fifty feet high, stand so thickly together that when in full leaf they form a solid wall of green. the vineyard, which is a mile square, is also surrounded by a single row of these superb poplars. a visit to one of the great raisin vineyards near fresno is a revelation in regard to the system that is necessary in handling large quantities of grapes. the largest raisin vineyard in the state, if not in the world, is that of a.b. butler. it comprises acres, of which a trifle over acres is planted to the best raisin grapes. butler was a texas cowboy, and came to fresno with very little capital. he secured possession of a section of land, planted it to grapes; he read everything he could buy on raisin making, but found little in the books that was of any value. so he made a trip to spain, and inspected all the processes in the malaga district. he gathered many new ideas. one of the most valuable suggestions was in regard to prunings and keeping the vine free from the suckers that sap its vitality. when he returned from this trip and passed through los angeles county he saw that the strange disease which was killing many hundred acres of vines was nothing else than the result of faulty prunings--the retention of suckers until they gained such lusty growth that their removal proved fatal to the vine. his vineyard is as free from weeds and grass as a corner of a well kept kitchen garden. the vine leaves have that deep glossy look which betrays perfect health. when my visit was made the whole crop was on trays spread out in the vineyard. these trays had been piled up in layers of a dozen--what is technically known as boxed--as a shower had fallen the previous night, and mr. butler was uncertain whether he would have a crop of the choicest raisins or whether he would have to put his dried grapes in bags, and sell them for one-third of the top price. fortunately the rain clouds cleared away. the crop was saved and the extreme hot weather that followed made the second crop almost as valuable as the first. the method of drying and packing the raisin is peculiar and well worth a brief description. when the grape reaches a certain degree of ripeness and develops the requisite amount of saccharine matter a large force is put into the vineyard and the picking begins. the bunches of ripe grapes are placed carefully on wooden trays and are left in the field to cure. the process requires from seven days to three weeks, according to the amount of sunshine. this climate is so entirely free from dew at night that there is no danger of must. the grape cures perfectly in this way and makes a far sweeter raisin than when dried by artificial heat. when the grapes are dried sufficiently the trays are gathered and stacked in piles about as high as a man's waist. then begins the tedious but necessary process of sorting into the sweat boxes. these boxes are about eight inches deep and hold pounds of grapes. around the sorter are three sweat boxes for the three grades of grapes. in each box are three layers of manila paper which are used at equal intervals to prevent the stems of the grapes from becoming entangled, thus breaking the fine large bunches when removed. the sorter must be an expert. he takes the bunches by the stem, placing the largest and finest in the first grade box, those which are medium sized in the second grade, and all broken and ragged bunches in the third class. when the boxes are filled they are hauled to the brick building known as the equalizer. this is constructed so as to permit ventilation at the top, but to exclude light and air as much as possible from the grapes. the boxes are piled in tiers in this house and allowed to remain in darkness for from ten to twenty days. here they undergo a sweating process, which diffuses moisture equally throughout the contents of each box. this prevents some grapes from retaining undue moisture, and it also softens the stems and makes them pliable. from the equalizing room the sweat boxes are taken to the packing room. here they are first weighed. the first and second grades are passed to the sorter, while the third grade raisins are placed in a big machine that strips off the stems and grades the loose raisins in three or four sizes. these are placed in sacks and sold as loose raisins. the higher grades are carefully sorted into first and second class clusters. after this sorting the boxes are passed to women and girls, who arrange the clusters neatly in small five pound boxes with movable bottoms. these boxes are placed under slight pressure, and four of them fill one of the regular twenty pound boxes of commerce. the work of placing the raisins in the small boxes requires much practice, but women are found to be much swifter than men at this labor, and, as they are paid by the box, the more skillful earn from $ to $ a day. it is light, pleasant work, as the room is large, cool and well ventilated, and there is no mixing of the sexes, such as may be found in many of the san francisco canneries. for this reason the work attracts nice girls, and one may see many attractive faces in a trip through a large packing house. one heavy shouldered, masculine-looking german woman, who, however, had long, slender fingers, was pointed out as the swiftest sorter in the room. she made regularly $ a day. the assurance of steady work of this kind for three months draws many people to fresno, and the regular disbursement of a large sum as wages every week goes far to explain the thrift and comfort seen on every hand. the five pound boxes of grapes are passed to the pressing machine, where four of them are deftly transferred to a twenty pound box. the two highest grades of raisins are the dehesa and the london layers. it has always been the ambition of california's raisin makers to produce the dehesa brand. they know that their best raisins are equal in size and quality to the best spanish raisins, but heretofore they have found the cost of preparing the top layer in the spanish style very costly, as the raisins had to be flattened out (or thumbed, as it is technically called) by hand. in spain, where women work for cents a day, this hand labor cuts no figure in the cost of production, but here, with the cheapest labor at $ . a day, it has proved a bar to competition. american ingenuity, however, is likely to overcome this handicap of high wages. t.c. white, an old raisin grower, has invented a packing plate of metal, with depressions at regular intervals just the size of a big raisin. this plate is put at the bottom of the preliminary packing box, and when the work of packing is complete the box is reversed and the top layer, pressed into the depressions of the plate, bears every mark of the most careful hand manipulation. mr. butler used this plate for the first time this season, and found it a success, and there is no question of its general adoption. every year sees more attention paid to the careful grading of raisins, as upon this depends much of their marketable value. the large packing houses have done good work in enforcing this rule, and the chief sinners who still indulge in careless packing are small growers with poor facilities. probably the next few years will see a great increase in the number and size of the packing houses which will prepare and market most of fresno's raisin crop. the growers also will avail themselves of the co-operative plan, for which the colony system offers peculiar advantages. geometrical progression is the only thing which equals the increase of fresno's raisin product. eighteen years ago it was less than , boxes. last year it amounted to , , boxes, while this year the product cannot fall below , , boxes. new vineyards are coming into bearing every year, and this season has seen a larger planting of new vineyards than ever before. this was due mainly to the stimulus and encouragement of the mckinley bill, which was worth an incalculable sum to those who are developing the raisin industry in california. besides raisins, fresno produced last year , , gallons of wine, a large part of which was shipped to the east. the railroad figures show the wealth that is produced here every year from these old wheat fields. the dried fruit crop last year was valued at $ , , ; raisins, $ , , ; and the total exports were $ , , . the largest bearing raisin vineyard in fresno is that of a.b. butler, who has over acres in eight year-old vines. the pack this year will be fully , boxes. as each box sells for an average of $ . , the revenue from this vineyard will not fall far below a quarter of a million. one of the finest places in the county is colonel forsythe's -acre vineyard, from which , boxes are packed. forsythe has paid so much attention to the packing of his raisins that his output commands a fancy price. this year he wanted to go to europe, so he sold his crop on the vines to a packing house, receiving a check for $ , . these, of course, are the great successes, but nearly every small raisin grower has made money, for it costs not over ½ cents per pound to produce the raisin, and the price seldom falls below cents per pound. good land can be secured in fresno at from $ to $ per acre. the average is $ an acre for first-class raisin land that is within ten miles of any large place. it costs $ an acre to get a raisin vineyard into bearing. in the third year the vines pay for cultivation, and from that time on the ratio of increase is very large. much of the work of pruning, picking, and curing grapes is light, and may be done by women and children. the only heavy labor about the vineyard is the plowing and cultivating. fresno is a hot place in the summer, the mercury running up to degrees in the shade, but this is a dry heat, which does not enervate, and, with proper protection for the head, one may work in the sun all day, without any danger of sunstroke. the colony system, which has been brought to great perfection around fresno, permits a family of small means to secure a good home without much capital to start with. where no money is paid for labor, a vineyard may be brought to productiveness with very small outlay. at the same time there is so great a demand for labor in the large vineyards, that the man who has a five or ten acre tract may be sure of work nearly all the year. in some places special inducements have been held out to people of small means to secure a five-acre vineyard while they are at work in other business. one colony of this sort was started eighteen months ago near madera, in fresno county. a tract of , acres was planted to muscat grapes, and then sold out in five and ten acre vineyards, on five years' time, the purchaser paying only one-fifth cash. the price of the land was $ an acre, and it was estimated that an equal sum per acre would put the vineyard into full bearing. thus, for $ , or, with interest, for $ , , a man working on a small salary in san francisco will have in five years a vineyard which should yield him a yearly revenue of $ . from the present outlook there can be no danger of over-production of raisins, any more than of california wine or dried fruits. the grower is assured of a good market for every pound of raisins he produces, and the more care he puts into the growing and packing of his crop, the larger his returns will be. for those who love life in the open air, there is nothing in california with greater attractions than raisin growing in fresno county.--_n.y. tribune._ * * * * * cold and mortality. by dr. b.w. richardson. during the seven weeks of extreme atmospheric cold in which the last year ended and with which the present year opened, every one has been startled by the mortality that has prevailed among the enfeebled and aged population. friends have been swept away in a manner most painful to recall, under the influence of an external agency, as natural as it is fatal in its course, and over which science, as yet, holds the most limited control. in the presence of these facts questions occur to the mind which have the most practical bearing. why should a community wake up one day with catarrh or with the back of the throat unduly red and the tonsils large? why, in a particular village or town, shall the medical men be summoned on some particular day to a number of places to visit children with croup? what is the reason that cases of sudden death, by so-called "apoplexy," crowd together into a few hours? why, in a given day or week, are shoals of the aged swept away, while the young live as before? these are questions which curative and preventive medicine have not yet mastered as might be desired. curative medicine, at the name of them, too often stands abashed, if her interpreter be honest; and preventive medicine says, if her interpreter be honest, "the questions wait as yet for full interpretation." still, we are not altogether ignorant; some circumstances appear to be followed by effects so definite, that we may almost consider we have before us, in true position, cause and effect. let us look at this position in reference to _the simple influence of temperature on the value of life_. if we observe the fluctuation of the thermometer by the side of the mortality of the nation at large, no calculable relationship seems, at first sight, to be traceable between the one and the other. but if, in connection with the mortality, care be taken to isolate cases, and to divide them into groups according to the ages of those who die, a singular and significant series of facts follow, which show that after a given age a sudden decline of the temperature influences mortality by what may be considered a definite law. the law is, that variations of temperature exert no marked influence on the mortality of the population under the age of thirty years; but after the age of thirty is reached, a fall of temperature, sufficient to cause an increased number of deaths, acts in a regular manner, as it may be said, in waves or lines of intensity, according to the ages of the people. if we make these lines nine years long, we discover that they double in effect at each successive point. thus, if the, fall in the temperature be sufficient to increase the mortality at the rate of one person of the age of thirty, the increase will run as follows: death at years of age will become deaths at years of age, at years, at years, at years, at years, and at years. in these calculations nothing seems to be wanting that should render them trustworthy; they resulted from inquiries conducted on the largest scale; they were computed by one of our greatest authorities in vital statistics, the late dr. william farr, and they accord with what we gather from common daily observation. they supply, in a word, the scientific details and refinements of a rough estimate founded on universal experience, and they lead us to think very gravely on many subjects which may not have occurred to us before, and which are as curious as they are important. we often hear persons who know little about vital phenomena, by which term i mean nothing mysterious, but simply the physics embraced in those phenomena which we connect with form and motion under the term life, harping on the one string, that man knows nothing of the laws of life and death. but what an answer to such presumption do the facts rendered above supply. life and death are here reduced, on given conditions, to reasonings as clear and positive as are the reasonings on the development of heat by the combustion of fuel. it is not necessary for the vital philosopher to go out into the towns and villages to take a new census of deaths to enable him to give us his readings of the general mortality under the conditions specified. he may sit in his cabinet, and, as he reads his thermometer day by day, predict results. there is a fall of temperature that shall be known by experience to be sufficiently deep and prolonged to cause an increase of one death among those members of the community who have reached thirty years. then, rising by a definite rule, there have died sixty-four, in proportion to that one, of those who have reached eighty-four years. this is sound calculation, and it leads to reflection. it leads one to ask, what, if the law be so definite, are curative and preventive medicine doing meanwhile, that they shall not disturb it? i fear that they hardly produce perturbations, and i do not see why they should; because, as the truth opens itself to the mind, the tremendous external change in the forces of the universe that leads to the result, is not to be grappled with nor interfered with by any specific method of human invention. the cause is too general, too overwhelming, too grasping. it is like the lightning stroke in its distance from our command; but it is widely spread, not pointed and concentrate; prolonged, not instantaneous; and, by virtue of these properties, is so much the more subtile and devastating. at first it seems easy to explain the reason why a sudden fall in temperature should lead to an increase in the number of deaths, and it is to be admitted that, to a certain extent, the reason is clear. animal power at different periods of life. without entering on the question whether heat is the animating principle of all living organisms, we may accept that in the evolution of heat in the body we have a measurement of the capacity of the body to sustain motion, which is only another phrase for expressing the resistance of the body to death. for example, if we assume that a healthy man of thirty respires sufficient air per day to produce as much heat as would raise fifty pounds of water at ° fahr. to ° fahr., and if we assume that a man of sixty in the same temperature is only able to respire so much air as shall cause him to evolve so much heat as would raise forty pounds of water from ° to °, we see a general reason why the older man should feel an effect from a sudden change in the temperature of the air which the younger would not feel; and if we assume, further, that a man of eighty could in the same time produce as much heat as would raise only twenty pounds of water from ° to °, we see a good reason why the oldest should suffer more from a decrease of external temperature than the other two. it is necessary, however, to know more than this general statement of an approximate fact; we ought to understand the method by which the reduction of temperature influences, and the details of the physiological process connected with the phenomena. when a human body is living after the age when the period of its growth is completed and before the period of its decay has commenced, it produces, when it is quite healthy, by its own chemical processes, so much heat or force as shall enable it, within given bounds, ( ) to move its own machinery; ( ) to call forth, at will, a limited measure of extra force which has been lying latent in its organism; and ( ) to supply a fluctuating loss that must be conveyed away by contact with the surrounding air, by the earth, and by other bodies that it may touch, and which are colder than itself. there is thus produced in the body, _applied_ force, _reserve_ force, and _waste_ force, and these distributions of the whole force generated, when correctly applied, maintain the perfect organism in such balance that life is true and steady. so much active force carries with it the power to perform so much labor; so much reserve force carries with it the power to perform a measure of new or extra labor to meet emergencies; so much waste force enables the body to resist the external vicissitudes without trenching on the supply that is always wanted to keep the heart pulsating, the chest breathing, the glands secreting or excreting, the digestive apparatus moving, and the brain thinking or absorbing. let us, even in the prime of manhood, disturb the distribution of force ever so little, and straightway our life, which is the resultant of force, is disturbed. if we use the active force too long, we become exhausted, and call on the reserve; if we continue the process, the result is failure more or less perfect, sleep, and, in the end, the last long sleep. let us, instead of exhausting the force, cut it off at the sources where it is generated; let us remove the carbon or coal that should go in as fuel food, and we create prostration, and in continuance a waning animal fire, sleep, and death; or let us, instead of removing or withdrawing the supply of fuel, cut off the supply of air, as by immersion of the body in water, or by making it breathe a vapor that weakens the combination of oxygen with carbon--such a vapor as chloroform--and again we produce, at once, prostration, sleep, or death, according to the extent to which we have conducted the process. lastly, if instead of using up unduly the active and reserve force, or of suppressing the evolution of force by the withdrawal of its sources, we expose the body to such an external temperature that it is robbed of its heat faster than it can generate it; if to supply the waste heat we draw upon the active and reserve forces, we call forth immediately the same condition as would follow extreme over-exertion, or suppression of the development of force; we call forth exhaustion and sleep, and, if we go far enough, death. we have had in view, in the above description, a man in the prime of life, in the center of growth, and decay. in regard to the force of animation in him, let us look at him now retrospectively and prospectively. in the past his has been a growing, developing body, and in the course of development he has produced an excess of force commensurate with the demands of his growth; this has enabled him gradually to bear more fatigue and more exposure, without exhaustion, and even with ease, until he has reached his maximum. when he has stopped in development, when he stands on a fair level with the external forces that are opposed to him, then his own force, for a short time balanced, soon stands second in command. he feels cold more tenderly; if his rest be broken, the demand for artificial heat is more urgent; if he lose or miss food, he sinks quickly; and, returning to our facts, as to the influence of the external temperature on mortality, these are the reasons why a fall in the thermometer sweeps away our population according to age so ruthlessly and decisively. if we analyze the facts further by the side of the diseases which kill the old, we find those diseases to be numerous in name, but all of two types. they are diseases which of themselves tend either to produce undue loss of force, or that tend to prevent the development of force at its origin. thus affections which are accompanied with exhaustive loss of fluids from the body, such as diabetes, dropsies, and hæmorrhages, are of the first class; affections in which due supply of air to the lungs is prevented are of the second class, especially bronchitis, a disease so commonly assigned as the cause of the deaths among the members of the aged and enfeebled population, that succeed immediately on an extreme fall of the thermometer. fall of temperature--mode of action. in what has been written above i have stated simply and in open terms the fact that the fall of temperature produces a specified series of results, by reducing the force of the living organism, and disposing it to die. we may from this point investigate, from a physiological point of view, the mode by which the effect is produced in the economy. how does the decline of temperature act? is the process simple or compound? extraction of heat. the process is compound, and into it there enter three elements. in the first place, the body is robbed rapidly of its waste force, and the reserve and active elements of force are, consequently, called upon to the depression of the organism altogether. this obtains because the medium surrounding the body, the air, unless it be artificially heated, removes from its contact with the body a larger proportion of heat than can be spared; and it might be possible to produce such an influence on the body by sudden extraction of its heat as to destroy it at once by the mere act. if a man could be surrounded with frozen mercury he would die instantaneously, as from shock, by the immediate extraction of his heat. but in ordinary cases, and under ordinary circumstances, the mere rapid extraction of waste heat is not sufficient to account for all the mischief produced by a low temperature; for by artificial warmth and non-conducting garments, we counteract the influence, and that, too, in a manner which proves pretty successful. we may, therefore, leave this element of extraction of heat as a most important, but not as the sole, agent of evil. suppressed oxidation. the second element is the effect on the process of oxidation of blood under the influence of cold. we all are aware that if a portion of dead animal or vegetable matter be placed at a low temperature, it keeps for a considerable time; and we have evidence of dead animals which, clothed in thick ribbed ice, have been retained from putrefaction for centuries. hence we say that cold is an antiseptic as alcohol is, and chloroform, and ammonia, and other similar bodies. cold is an antiseptic then, but why? because it prevents, even in the presence of a ferment, the union of oxygen gas with combustible matter. the molecules of oxygen, in order that they shall combine, and in their combination evolve heat, require to be distributed, and to be distributed by the form of motion known as heat; deprive them of this activity, and they come into communion with themselves, are attracted to each other, and lose to the extent of this attraction their power of combining with the molecules of other bodies for which they have an affinity. in an analogous, but more obvious way, we may see the same effect of motion in the microscopic examination of blood. in the blood, while it is circulating briskly in its vessels, there are distributed through it, without contact with each other, the millions of oxygen carriers called blood corpuscles. in the circulation in the free channels of the body, the arteries and veins, it is motion that keeps these corpuscles apart; we draw a drop of blood and let it come to rest on the microscope glass, and as the motion ceases the separated corpuscles run together, and adhere so firmly that we cannot easily separate them without their disintegration. if we were able to drive them in this state round the body, through the vessels, they would not combine readily with the tissues; they have, in fact, forfeited the condition necessary for such combination. so with the oxygen they carry; when its invisible molecules are deprived of the force called heat, which is motion, they do not readily combine with new matter. but perfect combination of oxygen and carbon in the blood is essential to every act of life. in the constant clash of molecule of oxygen with molecule of carbon in the blood lies the mainspring of all animal motion; the motion of the heart itself is secondary to that. destroy that union, however slightly, and the balance is lost, and the animal body is, in a plain word, _ill_. cold or decreased temperature, below a given standard, which for sake of comparison we may take at a mean of ° fahr., reduces this combination of oxygen and carbon in blood. in my lettsomian lectures to the medical society of london, delivered in , i entered very fully into this subject, and illustrated points of it largely by experiment. since then i have done more, and although i have not time here to state the details of these researches, i will epitomize the principal facts. i found then that, by exposing blood in chambers into which air can pass in and out, the blood could be oxidized at temperatures of ° if the distribution of air and blood were effectually secured, and i also found a proper standard of oxidation from a proper temperature. afterward i proceeded to test for combination at lower temperatures, and discovered a gradually decreasing scale until i arrived at ° fahr., when efficient combination ceased. of course, my method was a very crude imitation of nature, but it was sufficient to show this fair and reliable result, that the oxidation of blood decreases as the temperature of the oxygen decreases. from this point i went to animal life itself. i exposed animals to pure cold oxygen and to cold atmospheric air, and compared the results with other experiments in which animals of similar weight were exposed to warm air and warm oxygen. the facts gleaned were most important, for they proved conclusively that the products of combustion, that is to say, the products resulting from the union of oxygen and carbon, were reduced in proportion as the temperature of the oxygen was reduced. in the course of this inquiry another singular and instructive fact was elicited. it has been long known that at ordinary temperature, say °, pure neutral oxygen does not support animal life so well as oxygen that is diluted with nitrogen. in the nitrogen the molecules of oxygen are more freely distributed under the influence of motion, that is the meaning of the observed fact. what, then, would be the respective influence of low and high temperatures on the respiration of pure oxygen? to settle this question, animals of the same size and weight were placed in equal measures of oxygen gas and common air at a temperature of ° fahr., and with the inevitable result that the animal in the pure oxygen ceased to respire one-third sooner than did the animal in common air. carrying the inquiry further, i found that if the oxygen gas were warmed to ° fahr., the respiration was continued six times as long as in the previous experiment, while if the warming were carried to °, it was sustained twenty-four times as long. i reversed the experiment; i made oxygen with cold produce anæsthetic sleep in a warm-blooded animal. i need not carry this argument further; it is the easiest of the demonstrative facts of physiological science that reduction of temperature lessens the combining power of oxygen for blood, and therewith causes a reduction of animal force, and a tendency to arrest of that force, which, in the end, means _death_. mechanical cold. the third element in the action of cold is more purely mechanical, and this, though in a sense secondary, is of immense import. when any body, capable of expansion by heat, that is to say, by radiant motion of its own particles, is reduced in temperature, it loses volume, contracts, or shrinks. the animal body is no exception to this rule; a ring that will fit tightly to the warm finger will fall off the same finger after exposure to cold. the whole of the soft parts shrink, and the vessels contract and empty themselves of their blood. cold applied to the skin in an extreme degree blanches the skin, and renders it insensible and bloodless, so that if you prick it it does not bleed, neither does it feel. in cases where the body altogether is exposed to extreme cold this shrinking of the external parts is universal; the whole surface becomes pale and insensible; the blood in the small vessels superficially placed is forced inward upon the heart and vessels of the interior organs; the brain is oppressed with blood; sleep, or coma, as it is technically called, follows, and at last life is suspended. in exposure to the lowest wave of temperature in this country these extreme effects are not commonly developed; but minor effects are brought out which are most significant. in particular, the effect on the lungs is strongly marked. the capillary vessels of the lungs, making up that fine network which plays over the computed six hundred millions of air vesicles, undergo paralysis when the cold air enters, and in proportion as such obstruction from this cause is decisive, the blood that should be brought to the air vesicles is impeded, and the process of oxidation is mechanically as well as chemically suppressed. the same contraction is also exerted on the vessels of the skin, driving the blood into the interior and better protected organs. hence the reason why on leaving a warm room to enter a cold frosty air there is an immediate action of the visceral organs from pressure of blood on them, and not unfrequently a tendency to diarrhoea from temporary congestion of the digestive tract. three factors are at work, in fact, whenever the low wave of temperature affects the animal body; abstraction of heat from the body, beyond what is natural; arrest of chemical action and of combustion; paralysis of the minute vessels exposed to the cold. combined effects. we cannot view the extent of change in the organic life induced by the low wave of heat without seeing at once the sweep of mischief which exposure to the wave may effect. it exerts an influence on healthy life in the middle-aged man, and i know of no disease which it does not influence disastrously. is the healthy man exhausted, it favors internal congestion; has he a weak point in the vascular system of his brain, it renders that point liable to pressure and rupture, with apoplexy as the sequence; is he suffering from bronchial disease, and obstruction, already, in his air passages, here is a means by which the evils are doubled; has he a feeble, worn-out heart, it is unable to bear the pressure that is put upon it; has he partial obstruction of the kidney circulation, he is threatened with complete obstruction; is he indifferently fed, he is weakened generally. it is from this extent of action that the mortality of all diseases runs up so fast when the low wave of heat rolls over the population, affecting, as we have seen, the feeblest first. another danger sometimes follows which is remote, but may be fatal, even to persons who are in health. it is one of the best known facts in science that when a part of the surface of the body has been exposed long to cold, the greatest risk is run in trying suddenly to warm it. the vessels become rapidly dilated, their coats relax, and extreme congestion follows. but what is true of the skin is true equally, and with more practical force, of the lungs. a man, a little below par, goes out when the wave of temperature is low, and feels oppressed, cold, weak, and miserable; the circulation through his lungs has been suppressed, and he is not duly oxidizing; he returns to a warm place, he rushes to the fire, breathes eagerly and long the heated air, and adds to the warmth by taking perchance a cup of stimulant; then he goes to bed and wakes in a few hours with what is called pneumonia, or with bronchitis, or with both diseases. what has happened? the simple physical fact of reaction under too sudden an exposure to heat after exposure to cold. the capillaries of the lungs have become engorged, and the circulation static, so that there must be reaction of heat, inflammation, before recovery can occur. nearly all bronchial affections are induced in this manner, not always nor necessarily in the acute form, but more frequently by slow degrees, by repetition and repetition of the evil. colds are often taken in this same way, from the exposed mucous surfaces of the nose and throat being subjected first to a chill, then to heat. the wave of low temperature affecting a mixed population finds inevitably a certain number of persons of all ages and conditions on whom to exert its power. it catches them too often when they least expect it. an aged man, with sluggish heart, goes to bed and reclines to sleep in a temperature, say, of ° or °. in his sleep, were it quite uninfluenced from without, his heart and his breathing would naturally decline. gradually, as the night advances, the low wave of heat steals over the sleeper, and the air he was breathing at ° falls and falls to °, or it may be to ° or °. what may naturally follow less than a deeper sleep? is it not natural that the sleep so profound shall stop the laboring heart? certainly. the great narcotic never travels without fastening on some victims in this wise, removing them, imperceptibly to themselves, into sleep ending in absolute death. some simple rules. the study of the physiological influence of the wave of low temperature, and of its relation to the wave of mortality, suggests a few rules, simple, and easily remembered. . clothing is the first thing to attend to. to have the body, during variable weather, such as now obtains, well enveloped from head to foot in non-conducting substance is essential. who neglects this precaution is guilty of a grievous error, and who helps the poor to clothe effectively does more for them than can readily be conceived without careful attention to the subject we have discussed. . in sitting-rooms and in bedrooms it is equally essential to maintain an equable temperature; a fire in a bedroom is of first value at this season. the fire sustains the external warmth, encourages ventilation, and gives health not less than comfort. . in going from a warm into a cold atmosphere, in breasting the wave of low temperature, no one can harm by starting forth thoroughly warm. but in returning from the cold into the warm the act should always be accomplished gradually. this important rule may readily be carried in mind by connecting it with the fact that the only safe mode of curing a frozen part is to rub it with ice, so as to restore the temperature slowly. . the wave of low temperature requires to be met by good, nutritious, warm food. heat-forming foods, such as bread, sugar, butter, oatmeal porridge, and potatoes, are of special use now. it would be against science and instinct alike to omit such foods when the body requires heat. . it is an entire mistake to suppose that the wave of cold is neutralized in any sense by the use of alcoholics. when a glass of hot brandy and water warms the cold man, the credit belongs to the hot water, and any discredit that may follow to the brandy. so far from alcohol checking the cold in action, it goes with it, and therewith aids in arresting the motion of the heart in the living animal, because it reduces oxidation. . excessive exercise of the body, and overwork either of body or of mind, should be avoided, especially during those seasons when a sudden fall of temperature is of frequent occurrence. for exhaustion, whether physical or mental, means loss of motion in the organism; and loss of motion is the same as loss of heat. one further consideration, suggested by the subject of this paper, has reference to the bearing of the public toward the labors of the medical man in meeting the effects of the low wave of heat. the public, looking on the doctor as a sort of mystical high priest who ought to save, may often be dissatisfied with his work. let the dissatisfied think of what is meant by saving when there is a sudden fall in the thermometer. let them recall that it is not bronchitis as a cause of death, nor apoplexy, nor heart disease, as such, that the doctor is called on to meet; but an all-pervading influence which overwhelms like the sea, and against which, in the mass, individual effort stands paralyzed and helpless. when the doctor is summoned the mischief has at least commenced, and, it may be, is so far over that treatment by mere medicines sinks into secondary significance. then he, true minister of health, candid enough to bow humbly before the great and inevitable truth, and professing no specific cure by nostrum or symbol, can only try to avert further danger by teaching elementary principles, and by making the unlearned the participators in his own learning.--_the asclepiad._ * * * * * the treatment of glaucoma. as this disease is so fatal to vision, any remedy that may be suggested to diminish the frequency of its termination in blindness cannot fail to be read of with interest. m. nicati, in the _revue generate de clinique et de therapeutique_, has had marked success in the treatment of glaucoma by drainage of the posterior chamber, either by sclerotomy or by sclero-iritomy, as the conditions of the individual case may require.--_n.y. med. jour._ * * * * * a twin screw launch run by a compound engine. [illustration: twin screw steam launch gemini.] the launch shown in our illustration was built in new westminster, british columbia, canada. she is ft. keel and ft. beam, and has ft. depth of hold. she has an improved clarke compound engine, also shown in an accompanying illustration, with a high pressure piston four inches in diameter, and a low pressure piston eight inches in diameter, the stroke being six inches, and the engine driving two twenty-six inch screws. with pounds of steam, and making revolutions per minute, the launch attains a speed of nine miles per hour, thus fully demonstrating the adaptability of this engine to the successful working of twin screws. [illustration: the clarke compound twin-screw operating engine.] in the clarke engine, the exhaust pipe from the high pressure cylinder leads to the steam chest of the low pressure cylinder, while the piston in the upper cylinder is secured on a piston rod extending downward and connected with a piston operating in the lower cylinder, the exhaust pipe from the latter leading to the outside. on the piston rod common to both cylinders is secured a crosshead pivotally connected by two pitmen with opposite crank arms on crank shafts mounted to turn in suitable bearings on the base, which also supports a frame carrying the low pressure cylinder, on top of which is a frame supporting the high pressure cylinder. the valves in the two steam chests are connected with each other by a valve rod connected at its lower end in the usual manner with the reversing link, operated from eccentrics secured on one of the crank shafts. the crank arms stand at angles to each other, so that the crank shafts are turned in opposite directions, and the position of the link is such that it can be readily changed by the reversing lever to simultaneously reverse the motion of the crank shafts. on the crank shafts are also formed two other crank arms pivotally connected by opposite pitmen with a slide mounted in vertical guideways, supported on a frame erected on the base, the motion of the crank shafts causing the vertical sliding motion of the slide traveling loosely in the guideways, and thus serving as a governor, as, in case one of the propellers becomes disabled, the power of the shaft carrying the disabled propeller is directly transferred to the other shaft through the crank arms, pitmen, and slide, and the other propeller is caused to do all the work. all the parts of the engine are within easy reach of the engineer, and there are so few working parts in motion that the friction is reduced to a minimum. it is said that the plan of construction and the operation of this engine have been carefully observed by practical engineers, and that, considering the dimensions of the boat, her speed, the smallness of the power, the ease with which she passes the centers, the absence of vibration while running, and the very few working parts in motion, the engine is a notable success. she can be run at a very high velocity without injury or risk, and is designed to be very economical in cost and in weight and space. this engine has been recently patented in the united states and foreign countries by mr. james a. clarke, of new westminster. * * * * * improvements in the construction of river and canal barges. by m. ritter (knight) von szabel, late austrian naval officer, of vienna. this innovation consists essentially in an arrangement by which two distinct vessels, on being revolved round their longitudinal axis to an angle of °, can be combined into one single duplex vessel, or, to put it in different words, a larger vessel is arranged so that it can be parted into two halves (called "semi-barges"), which can be used and navigated with equal facility as two distinct vessels, as if combined into one. by the combination of the two semi-barges into one duplex barge the draught of the vessel is nearly doubled, the ratio existing between the draught of a loaded semi-vessel and the equally loaded duplex vessels being : (up to . ) the advantage of the invention consists: . in this difference of draught. . in the smaller width of the semi-vessel as compared with the duplex vessel. . in the fact that the combination and separation of the vessels can be effected, without the least disturbance of the cargo, in a minimum of time. it facilitates the utilization, to the highest possible extent, of the varying conditions and dimensions of canal locks and rivers. the transition from rivers to canals, and from larger canals to smaller ones, is expedited by the possibility afforded of, on the arrival at the locks, dividing the vessel in a space of a few minutes; of passing with the semi-vessel, singly, the various smaller locks or the shallow canal, after which the two sections may be re-combined and navigated again as one vessel. the process of "folding up" the two vessels will of course take longer than that of separation. on rivers, the channels of which are interrupted by sand banks and rapids, the same operation may be carried out, thus avoiding the expense and delay necessitated by, perhaps, repeated "lightering," i.e., reduction of the cargo. thus, the through traffic on large rivers like the danube, with its repeated obstacles to navigation, such as the "iron gate," and several sand-banks known and dreaded by bargemen, would be materially facilitated, any necessity for unloading part of the cargo being obviated; moreover, such a duplex vessel composed of two semi-vessels affords the advantage of utilizing to a fuller degree the power of traction, and one large vessel will be more convenient for traffic than two smaller ones. further, the mode of construction of the semi-vessels--both ends of which are of a similar pattern--allows of their being navigated up and down a water channel without the necessity of turning them round; provision having also been made for the fixing of the rudder at either end, which would therefore merely require exchanging. this is of some advantage in narrow river beds and canals, and applies equally to the duplex vessel as to the single semi-vessels. [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] [illustration: fig. .] each semi-barge on its part is also constructed of two equal halves--which are, however, inseparable--and as there is no distinct stem or stern, any one of these semi-vessels will fit any other semi-vessels of the same dimensions, and can be attached to the same by means of the coupling apparatus, and the two "folded up" into one duplex vessel. this process does not present any material difficulties. the two single boats on being coupled together can be made to lean over toward each other, by filling their lateral water compartments, to such an extent that the further closing up can be easily effected by means of specially constructed windlasses. in the case of petroleum vessels the "folding up" operation is facilitated by the circumstance that the petroleum may be made to serve the purposes of water ballast. as regards the size and tonnage of the new vessels, this will of course depend on the local condition of the rivers and canals to be navigated. thus a vessel destined for traffic on canals with locks of varying dimensions will have to be adapted to the dimensions of the smallest existing lock. supposing the size of the latter to be such as found in the case of the rhine-marne or the rhine-rhone canal, or on the neckar down to cannstadt, or in the danube-main canal and some smaller canals in the weser district, etc., viz.: length of lock . meters. width . " depth . to . meters. the semi-barge may be made meters in length, meters in breadth and . meters total depth, and with a draught of . meters will be capable of carrying a load of tons (of , kilos each). correspondingly the duplex vessel will be able to carry tons, with a minimum draught of . meters and a width of . meters, but, with a favorable height of the water level, the draught of the semi-barge may be increased to . and that of duplex vessels to . meters. where not limited to certain proportions by the dimensions of the locks to be passed, the vessel may in the first place be made longer; the width and height may also be increased accordingly (provided that the proportion of breadth to width is kept within the ratio : . ), so that the semi-barges may be constructed for a single burden up to tons, or for the duplex vessel. as regards the nature of the cargo, parcels would not be admissible in this instance, but any kind of homogeneous cargo would be suitable which would bear laying over on one side. thus this style of vessel would be well adapted for petroleum tank vessels, for the transport of all kinds of cereals, flour, coffee, and sugar in sacks--these latter being held in position by an arrangement of planking and boards so as to prevent any overturning of the goods on the vessels being folded up or taken apart. similarly in the case of a cargo of loose grain or other loose produce, the same must be prevented from being upset by a kind of wooden casing. two semi-vessels loaded with different cargoes may be coupled together, provided that there is not too much difference between their respective draughts. slight differences may be balanced by the water compartments being filled to a greater or smaller extent. the peculiar position of the hatches allows of loading the semi-vessels separately as well as when coupled together. if there is for the time being no necessity for using the vessels in their capacity of separate and duplex barges, any kind of cargo might be loaded that does not require large hatches. the vessels, on account of their more complicated construction, will be somewhat more expensive, but wherever the advantage offered by them outweighs the extra expenditure, they can be used with success. the innovation might be of particular importance where a new canal system is being constructed, since the latter might be subdivided into main canals and branch canals--similarly as in the case of ordinary and narrow gauge railways--the main canal being built of a larger section and with larger locks to suit the duplex barges, while the branch canals could be planned of smaller dimensions calculated to suit the semi-barge. thus the first cost of such a canal system would be materially reduced as compared with a canal installation of one uniform section throughout. likewise in mountainous districts with rock soil it would be an important consideration whether a canal had to be blasted out of the solid rock or a tunnel cut, in dimensions suitable for a vessel of or of square meters section below the water line. in this case, even in certain portions of a main canal--where rendered desirable by the rocky nature of the ground--a smaller section might be adopted, which would only be large enough for single semi-barges, so that the duplex vessel would in these instances have to be taken apart in the same way as in a branch canal. the saving to be effected by constructing a canal on this principle, as compared with a canal of one uniform section throughout, must be considerable, and the advantages of the arrangement are apparent. the appended figures will further illustrate the arrangement. fig. shows two separate semi-barges ready to pursue their journey independently. fig. shows two semi-barges coupled together ready to be "folded up" by means of ropes and specially constructed windlasses--their lateral water compartments having previously been filled. fig. shows the duplex vessel after the "folding up" operation just described; and figs. and show the cross section of two loaded semi-barges as outlined in figs. and . these figs. and will also serve to illustrate the manner in which sacks and loose produce should be loaded. fig. also shows the filled water compartments, and the effect of their weight in making the boats lean toward each other. the materials most suited for this new style of vessel will be iron and steel such as generally used in the construction of canal and river vessels. the new ship can be moved by any motor or driving implement, nor could there technically a great difficulty be found for making the boilers move on a quadrant-like rail base in the shape of a circle segment's quarter, or for building a double screw steamer by combining two single screw propellers. may be a ship owner is willing to submit the innovations to an attempt, so much the more as there is running no great risk by doing so; for in case the ships should not answer the expectations, both separable as well as joinable, they can be used like single ships, without any further alteration being made, except as to the loading gaps. the above invention is covered by united states patent no. , . any further information may be had by addressing m. v. szabel, ix bezirk, beethovengasse , wien, austria. * * * * * weldon's range finder. colonel weldon has recently considerably modified and improved his ingenious range finder, and we illustrate herewith from _engineering_ the form in which it is now manufactured. it consists of a metal box, the lid of which is shown open in the engraving, and on this lid are fitted three prisms which are the essential constituents of the instrument. when the lid is closed, these, with the compass and level, also attached to the lid, lie inside the metal box, and are thus thoroughly protected. the upper prism marked is a right-angled one and is mounted with the right angle outward; looking into the left-hand corner of this prism one will see in it, by double reflection, objects lying on one's right hand. below this is a second prism with a principal angle of deg. min. sec., and below this a third with a principal angle of deg. min. sec. a level and a compass are also mounted on the lid as shown. to use the instrument the observer stands so that the object the range of which is required lies on his right hand, and looking into the left-hand corner of the upper prism views it there by double reflection from the internal faces of the prism. at the same time looking through the opening shown in the lid below the prism he selects some object, which appears nearly in line with the image seen in the prism. he then shifts his position till these two images coincide, in which case lines joining him with the two objects will make right angles with each other. in fig. , o is the object whose range is required, d the object seen by direct vision, and a the position of the observer. the observer now marks his position on the ground, and shifting the instrument looks into the left-hand corner of the second prism, when he again sees the image of the object, whose range is required, by double reflection, but lying now to the right of the object, d. he then retires, keeping in line with a and d, till he reaches b, when the two images again coincide; the lines joining them and the observer now make an angle of deg. min. sec. then in the triangle, oba, oa = tan deg. min. sec. x a b = ab. the length ab is easily paced, and the distance oa is times this length. a longer base, and probably greater accuracy, can be obtained by using the second prism only, as indicated in fig. , in which case the distance of the object is times the distance bc. this second prism is, however, best adapted for predicting the range of moving objects. three observers are required. two of them have finders, while the other measures the distance between the two. the first two observers separate, and no. takes a position such that the object is reflected to one side of observer no. , whom he views by direct vision. as the object continues to move, its image gets nearer and nearer no. , who during the whole of the time moves a little to one side or the other, so as to keep the image of the object constantly in line with no. . just as the image of the object gets very near no. , no. calls out "ready," the distance between the two observers is taken by the third, and when the image of the object actually falls on no. its distance is just times the distance between them, and the guns set to this range are fired by word of command from no. . [illustration: fig. . & fig. .] by using the third prism in conjunction with the second a still longer base of one-fourth the distance of the object can be employed. the range finder can also be used as a depleidoscope for transit observations. for this purpose it is mounted on a block of wood by means of elastic band and leveled by the level on its lid, being at the same time set in the meridian of the place. the lid is opened to make an angle with the horizon equal to the latitude of the place of observation. on looking into the upper prism two images of the sun will be seen on each side of the apex of the prism, which gradually approach each other as the sun nears the meridian, and finally coincide as it passes it, the time of which being noted gives the longitude of the place. extensive trials of the instrument have been made both in this country and in india, which agree in showing that the average error in using the instrument is about ½ to ½ per cent. * * * * * wheels linked with a bell crank. [illustration: fig. ] there are four ways in which a connecting rod is made use of in machine work. the first is in linking two wheels together that stand in the same position, but a slight distance off centers. the rod in this case has only to lead the driven wheel around by connecting it with the driver, and consequently has only to endure a pulling strain in the direction of its length. the second is when the rod is called upon to stand a pull and a push at every revolution. the third takes in the matter of the twisting strain that a rod can manage; but the fourth brings the hardest usage that a connecting rod can be called upon to endure, and that is by making a lever of the rod to get a driving action by prying on a fulcrum in the center. in fig. is seen a case of this kind taken from a machine in which a disk engine was made use of. the rod has a chance to turn about on its center from a ball and socket joint, and engages with both wheels in nicely fitted journals, and boxes set in line with the center of the socket joint, so that when one wheel turns, the rod pries the other around by using the rod as a lever and the ball joint for a fulcrum, giving a uniform leverage all the while, with no dead centers. [illustration: fig. .] to set this arrangement around at right angles, or where the shafts will bring the wheels together, as for bevel gears, a bent lever arm would need to be used, as shown in fig. , but the bend in the connecting arms brings in another feature that must be provided, as it allows the wheels to turn either with or against each other, and leaves two places where the bent arms will come to a dead center. what is needed here is another element that will take all the twisting strain on the rod and keep the pitch of both arms alike in every portion of a revolution. to do this the ball and socket joint will need to be replaced by a gambrel joint like a ship's compass, and arranging the bent driving arms as shown in fig. ; then the driving end of the connecting frame will move about in a true circle, producing as great a tendency to turn the driving wheel in one position as another. in this arrangement there must be at least six nicely fitted journals and their bearings, four of which will be required to take care of the forked connecting rod that joins the wheels together. besides all this the bearings must all line up with the same center that the shafts are centered from or there will be a "pinch" somewhere in the system. it may seem at first that there must be more or less end-on movement provided for, and that the bearings should be spherical; but that it is not the case will be noticed when all the points are understood to be working from one center similar to that provided for in bevel gears.--_boston journal of commerce._ [illustration: fig. .] * * * * * the decorative treatment of natural foliage.[ ] [footnote : lectures before the society of arts, london, .] by hugh stannus. _lecture i._ § .--the elements of decoration. the chief impelling motives which have caused that treatment of objects which is now termed _decorative_, have been: (a) that necessitated by the usage, which is functional; (b) that resulting from the instinct to please the eye, which is Æsthetic; (c) that arising from the desire to record or to teach, which is the didactic motive; the Æsthetic instinct of the early peoples was gratified by: (a) the _forms_ of their weapons or tools; (b) the _patterns_ with which they are decorated; (c) the _imitation_ of the surrounding animals, e.g. the deer scratched on the horn at the british museum. imitation was afterward applied to the vegetable creation; and much of what is termed ornament was derived from that class of elements. the elements of decoration are the material used by the artist. they might be considered to include everything that is visible; but since decoration is a result of the æsthetic instinct, the field is narrowed to such as are pleasing _at the first glance_. and the selection is further limited to such as are suitable to the shape and size of objects. they may be classified according to their relative dignity, as follows: the human form, animal forms, natural foliage, artificial objects, artificial foliage, and geometrical figures. § .--the two kinds of foliage. a distinction is made between natural and artificial foliage. they have much in common; and consequently many have supposed that our western artificial foliage is merely a very-much-conventionalized version of natural foliage. the supposition is correct with regard to eastern pattern work, but not in western architectural ornamentation. a simple generalization may make this clear. the ordinary stock foliage of the ornamentist was evolved in connection with: (in the west) (in the east) architecture, textiles, as in greece. as in persia. hence the primary elements of decoration were derived from: (in the west) (in the east) geometrical lines, natural flowers and leaves, e.g. the meander, spiral, etc. e.g. the pine, pomegranate, etc. further, it may be observed that the method of treating these elements has been different: (in the west) (in the east) the geometrical lines the natural foliage was were enriched by the introduction codified by the introduction of the details of of geometrical arrangement; natural vegetation; thus thus becoming becoming gradually more gradually more _naturalesque_. _artificial_. an approximation between the two treatments, sometimes appears; but the two kinds--artificial, and natural--are essentially different in origin; and should be kept distinct in their application. this approximation may be shown, in a tabular arrangement, thus: geometry...........................................................nature the patterns are merely the plants are copied as straight lines, dots, and accurately as possible. portions of circles. the lines become stems. the plant is applied without repetition. leaves are added to the repetition is used with the stems. plants. serration is added to the weaving economy induces leaf-edge. symmetry. similarity of serrated symmetry induces geometrical leaf-edge to the akanthos severity, and the omission plant, is observed; of all details of the imitation becomes more original plant which are not direct; and this artificial easily worked in connection foliage becomes termed with geometrical "acanthus." arrangement. flowers generally circular the flowers and leaves in mass-shape, are added (_only_) survive; the growth at the ends of the spiral of the stems is forgotten; stems. and tradition does the rest. § .--application of the two kinds. each of these two kinds of foliage has its own proper use. artificial foliage is appropriate to the enrichment of architecture; and natural foliage to those objects which are not architectural, but are termed "movables," including under this term, furniture, and more especially hangings and other applications of the textile art. this may be seen on comparing the two columns below, of which the l.h. one refers to architecture, and the r.h. one to natural foliage. (architecture) (natural foliage) rules: governed by severe exhibits _apparent_ playful rules of repetition, freedom. there _are_ axiality, symmetry, etc., underlying rules, which which are apparent to are detected by the scientific the passer-by. hence botanist; but these artificial foliage, being are not seen by the casual regular in its structure, observer. is more appropriate than the (apparently) irregular growth of natural foliage. characteristics: rigidity and stability. elasticity and tremulousness in every breeze. lines of composition: geometrical lines. in determinate curves, the geometrical lines which are very subtile, and spirals of artificial and varied, and therefore foliage demand an unmoving suitable to a hanging and surface for proper view. swaying material. the curves of nature they would generally be spoiled are not spoiled when on a if not on a plane surface. folded material. distribution: symmetrical. the balanced. the growth symmetry of artificial of natural foliage is generally foliage is appropriate to symmetrical; but that of architecture. this is not apparent. beauty: depends on _form_, with more appropriate to objects color as a secondary adjunct. which depend on _color_ for their principal charm. there have been waves of the desire to introduce natural foliage into architecture (e.g. in the "decorated period" of gothic architecture); but the artificial elements have always proved too strong, and the two have never mixed. in architecture, everything has three dimensions; and the artificial foliage is carved with leaves, etc., of a suitable thickness: in natural foliage the tenuity of leaves, etc., is such that it cannot be reproduced. even in the architraves round the glorious doors of florence the natural foliage is not always a success; and where ghiberti has stopped short in the ductile bronze, it is not probable that the modern carver will succeed in stone. it may therefore be suggested that the close imitation of natural foliage should be confined to objects of _two_ dimensions, i.e., to plane surfaces and figured materials. this selection of the elements of decoration, according to their association, is analogous to the selection made use of by the poet, from the words and ideas, which are his materials. it will be observed that, as on a classic or heroic subject, the choice is of learned words and classical ideas, and on a domestic or pastoral one, simple words and homely similes are used--so, in conjunction with the severe forms of architecture, the formal character of artificial foliage is suitable; and for decorating textiles and other movable accessories, the natural foliage, with which the earth is clothed and beautified, is appropriate. enrichment of surface may be beautiful for one reason; imitation of nature is beautiful for another. when imitations of natural foliage are introduced decoratively on a surface, then may it be twice beautiful--first, in the _principles_ according to which the distribution is arranged; and secondly, because of the _elements_ which are worked in being beautiful in themselves. geometrical elements might be so used as to serve the first end, but can never fulfill the second: storiation fulfills the second; but its increase of interest absorbs the first. this course of lectures is intended to treat of natural foliage, leaving artificial foliage to be dealt with at another opportunity. it is not historical. the history of the decorative treatment of natural foliage, showing its evolution in the past, is a large and interesting theme; but, unless this were accompanied by critical remarks based on given principles, the method might be barren of results. tradition is not to be undervalued; but the student should be led to tradition through principles. it is further intended more especially to apply to the æsthetic use. when natural foliage is used Æsthetically (i.e., decoratively), then the shape of the surface should govern the mass shape of the foliage, and there should be parallelism between them (see § ). when used didactically (i.e., symbolically), then the foliage may be treated more freely. § .--the four treatments. there are, broadly speaking, four methods of treating natural foliage. these may be arranged in a chart, according to their relation to the two poles of art and science; from realism (which is all art and no science) to the "botanical analysis" method (in which is a little science but no art), thus: the first two of these methods are artistic and legitimate: the others are inartistic and misleading. before treating of the artistic methods it will be well to clear the ground by dismissing the others. art pole..........................................science pole realism | conventionalism | disguised | botanical (see § ). | (see § ). | artificialism | analysis | | (see § ). | (see § ). § .--the botanical analysis treatment. in this method the student was taught (i) to draw each plant with the stem _straightened out_, the leaves _flattened out_, and the flowers represented as in _side elevation_ or _plan_. (ii) the flowers were further _pulled in pieces_, and the petals were _flattened out_ in a manner similar to the entomologists' practice of displaying their "specimens" scientifically. often, also (iii) the stems and buds were _cut through_; and "patterns" were made with the sections. with regard to the first of these practices (i): it should be observed that much of the beauty of appearance of natural foliage results from the variety of view, the subtile curvature, and the foreshortening, as seen in perspective; and that to sacrifice all these for the sake of a _diagram_ would be a wasted opportunity. with regard to the other practices (ii) and (iii): it is obvious that these statements of the facts of the plant are useful as a part of the science of botany; but can no more be considered as making decoration than anatomical diagrams can be looked upon as pictures. some knowledge of external botany is useful to a pattern artist as some knowledge of external anatomy is useful to the pictorial artist. in each of these cases, the science, which discovers and records facts, is subservient to its sister, art, which uses the facts to interpret appearances; and, when scientific diagrams are put forth as art, the science is in its wrong place: it has then been treated as if it were the building instead of being only the scaffolding; and the results of such attempts cannot be considered as complete or final. examples of this method are given in figs. and . it was officially encouraged about twenty-five years ago; and books like "plants, their natural growth and ornamental treatment," and "suggestions in floral design," both by f. edward hulme, f.l.s., etc., show it at its best. [illustration: fig. .] in criticising this method, there is no desire to cast any slight upon those who were responsible for it. they were groping in the dark, and did the best they knew, according to their lights. but japanese work was not known at that time, and, but for that, the pattern artist of to-day might still be occupied in pinning leaves and flowers against the wall. it was, moreover, a protest against the cabbage rose on the hearth rug, that some may still remember with shuddering. [illustration: fig. .] § .--the disguised artificiality treatment. in this method the student was taught to sketch out what he considered to be good curves and spirals; and then (i) to bend the selected plant so that its stem might coincide with them, regardless of its own proper natural growth; or (ii) to deck out the first drawn spirals with the leaves and flowers of the selected plant. with regard to the first of these practices: it is much more foolish than the analysis method; and is little short of blasphemy against the great designer. he has determined how each plant shall grow: how, within limits of cultivation, its stems and branches shall separate, each to seek its own share of air and sunshine; how its leaves shall stand erect or droop, each according to its function; and always in perfect beauty. and further: how each family of plants shall have its own method of branching; which is as much a part of its character and often of its beauty as are the flowers and leaves. the second practice, which generally produces a result similar to the first, is quite as unthinking. it is more often practiced; and is responsible for many of the labored and uninteresting designs which are common. if the pattern-artist deck-out the old worn-out and common place spirals with leaves and flowers borrowed from nature--the result is like the "voice of jacob and the hands of esau;" it is merely a disguise of artificiality. an example of this method is given in fig. . it was generally practiced in germany; and books like "das vegetabile ornamente," by k. krumbholz, show it at its best. [illustration: fig. .] if this treatment were universally followed--there would soon be an end to design with natural foliage. the spectator might observe one border which appeared to be a rose, another a tulip, the third a thistle, and the fourth a fuchsia; and, on examination, discover that these were not rose, tulip, thistle, and fuchsia; but merely that very artificial old friend--the spiral-scroll--_in disguise_. an apologist for this method remarks:--" ... in such matters as the ramification of plants, ... nature is always making angles and elbows [_sic_] which we are obliged, in decorative treatment, to change into curves for our purpose;...". this opinion needs only to be applied to animals in order to exhibit its absurdity; and with regard to plants, it will be seen that this tampering has not even the poor merit of success. § .--note on symmetry. a desire for symmetry often accompanies these two treatments. this is a quality to be avoided whenever possible in natural foliage design. the so-called "turn-over patterns" are an economy in weaving-design, but the economy is of the wrong kind. an artist should spend his thought to spare material or cost in working. when he spares his _thought_--making the least amount of thought cover the greatest amount of surface--then is his work worth to the world just what it has cost him, i.e., very little. so injurious is the influence of symmetry in natural foliage design, that it might almost be a test question--"is the design symmetrical?" when the exigencies of machine-reproduction necessitate this with natural foliage--it is a hardship which the artist regretfully accepts, and no one would willingly make a design for hand-reproduction which was symmetrical; rather would he spend himself to insure the worthier result which ensues from balance. an example of symmetry is given in fig. ; and of balance in fig. . each panel contains two classes of elements:--natural foliage (i.e., two branches of the bay tree), and an artificial object (i.e., a ribbon which ties them). the lower element (i.e., the ribbon) is treated symmetrically in both panels: the higher element (i.e., the branches) are _symmetrical_ in the former panel, and _balanced_ in the latter. this latter treatment, will be seen to be not only the more interesting, but the more like the infinite variety of nature; while the former is a wasted opportunity, and contrary to nature. [illustration: fig. .] the student will observe by experience that the mind soon tires of artificiality, both in curvature and in symmetry; the lines of nature have a pleasant freshness and inexhaustible variety; and the _natural_ method of treating nature is not only the most true, but also the most beautiful. [illustration: fig. .] § .--realism and conventionalism: definitions. realism--the result of _realistic_ treatment, i.e., the attempt to render the reproduction as like the reality as is possible, even to the verge of deception--is the aim of the pictorial-artist. in pictures the surface appears to have been annihilated, and the spectator beholds the scene as if there were a hole through the wall. it is not the highest, and should not be the only aim in art; but it has always been sought for and admired. it requires perfect conditions, of materials and tools; i.e., _complete technical appliances_. conventionalism--the result of _incomplete technical appliances_, and the attempt to render so much of the beauty of the original as is possible, with due regard to their capabilities--is the aim of the decorative-artist. it is not the highest aim; though a necessary curb in decorative-art, both for the technical reason, and also as a result of the position or function of the object. it will thus be seen that the two words, when used with regard to foliage of any kind, refer to the _method of representing it_, and not to its kind or its manner of growth. § .--scales from realism to conventionalism. these two methods, when applied absolutely, form the two extremes:--the most complete realism being at one end, and the most limited conventionalism at the other. there are scales of gradual reduction between them, which may be shown on two charts: (i) reduction in the number of parts which preserve their realistic rendering. (ii) reduction in the degree of realism through all parts. (i) according to the number of the features or parts of the design which are treated with less than realism. thus there might be a panel representing a window-opening with an architectural framing, with a flower-vase on the sill, and a landscape-background. the first part to be reduced in realistic rendering would be the background, the second would be the framing, leaving the third, the flower-vase, as the survival. this is a scale of reduction in _number of parts_. it may be shown, in tabular arrangement, thus:-- realism............................................conventionalism. complete pictorial realism, in which all parts are realistically represented (see § ). semi-pictorial realism, in which the back-ground is reduced to a flat-tint, while all the remaining parts are realistically represented (see § ). decorative realism, in which the chief feature (_only_) is realistically represented, and all the other parts are reduced to conventional renderings (see § ). complete conventionalism, in which all parts are reduced to conventional renderings (see conventionalism). inasmuch as there is some realistic part remaining in each of the first three methods--these are classified under the heading of realism. (ii) according to the degree in which color, gradation, or shading, is sacrificed, in consequence of the limited means at the disposal of the artist; resulting in the gradual departure from realism to the most severe conventionalism. the reduction is applied to all parts of the work. this is a scale of reduction in _degree_. there are two varieties in each degree; and they are marked with italic letters. it may be shown, in tabular arrangement, thus:-- realism.............................................conventionalism. complete realism, in which all parts are represented, in proper colors, and perfect gradation, with correct light and shade (see § ). first degree of conventionalism, in which all parts are represented: (a) by a reduced number of pigments, the other qualities remaining; (b) by reduction in gradation and shading to flat-tints of several pigments (see § ). second degree of conventionalism, in which all parts are represented: (c) by a reduction to monochrome of color, with gradation (_only_) remaining; (d) by reduction to monochrome of white and black, with gradation (_only_) remaining (see § ). third degree of conventionalism, in which all parts are represented: (e) by reduction to a flat-tint of one pigment on a ground of another; (f) by reduction to a flat-tint of white on black, or _vice versa_ (see § ). ultimate conventionalism, in which all parts are represented; (g) by reduction to outline of several pigments; (h) reduction to outline of one pigment (see § ). inasmuch as realism ceases so soon as any reduction in the three qualities (of color, gradation, and shadow) is introduced; and the treatment becomes more conventional in each method after the first--these are classified under the heading of conventionalism. [there is an analogous scale of reduction in form, from the complete-relief of an isolated statue to the flatness of a floor-plate; but this does not belong to the present subject.] * * * * * the cyclostat. the various processes commonly employed for the observation of bodies in motion (intermittent light or vision) greatly fatigue the observer, and, as a general thing, give only images, that are difficult to examine. we are going to show how prof. marc thury, upon making researches in a new direction, has succeeded in constructing an apparatus that permits of the continuous observation of a body having a rapid rotary motion. the principle of the method is of extreme simplicity. [illustration: figs. , , and .--diagrams explanatory of the principle of the cyclostat.] let us consider (fig. ) a mirror, a b, reflecting an object, c d, and revolving around it: when the mirror will have made a half revolution, the image, c' d', of the object will have made an entire one. the figure represents three successive positions of the mirror, distant by an eighth of a revolution. the structure of the image shows that it has made a quarter revolution in an opposite direction in each of its positions. but if (fig. ) the body itself has revolved in the same direction with an angular velocity double that of the mirror, its image will have described a circle in remaining constantly parallel with itself. the image will be just as insensible as the object itself; but it is very easy to bring it back to a state of rest. let us suppose (fig. a) the observer placed at o, the revolving object at t, the axis of rotation being this time the line o f. let us place a mirror at a b and cause it to revolve around the same axis; but, instead of looking at the image directly in the mirror, let us receive it, before and after its reflection upon a b, upon two mirrors, c d and d e, inclined ° upon the axis of rotation of the system; the image, instead of being observed directly in the mirror, a b, will always be seen in the axis, o f, and will consequently appear immovable. the same result may be obtained (fig. b) with a rectangular isosceles prism whose face, a b, serves as a mirror, while the faces, a c and b d, break the ray--the first deflecting it from the axis to throw it on the mirror, and the second throwing it back to the axis of rotation, which is at the same time the line of direction of the sight. the principle of the instrument, then, consists in causing the revolution, around the axis of rotation of the object to be observed, of a mirror parallel with such axis, and in observing it in the axis itself after sending the image to it by two reflections or two refractions. in reality, the entire instrument is contained in the small prism above, properly mounted upon a wheel that may be revolved at will; and, in this form, it may serve, for example, to determine the rotary velocity of an inaccessible axis. for this it will suffice to modify its velocity until the axis appears to be at rest, and to apply the revolution counter to the wheel upon which the prism is mounted, or to another wheel controlling the mechanism. but mr. thury has constructed a completer apparatus, the _cyclostat_ (fig. ), which, opposite the prism, has a second plate whose actuating wheel is mounted upon the same axis as the first, the gearing being so calculated that the prism shall revolve with twice less velocity than the second plate. this latter, observed through the prism, will be always seen at rest, and be able to serve as a support for the object that it is desired to examine. [illustration: fig. .--the cyclostat. . general view of the apparatus. . section of the ocular, o.] the applications are multitudinous. in the first place, in certain difficult cases, it may serve for the observation of a swinging thermometer, which is then read during its motion. then it may be employed for the continuous observation of a body submitted to centrifugal force. apropos of this, we desire to add a few words. most of the forces at our disposal, applied to a body, are transmitted from molecule to molecule, and produce tension, crushing, etc. gravity and magnetic attraction form an exception; their point of application is found in all the molecules of the body, and they produce pressures and slidings of a peculiar kind. but these forces are of a very limited magnitude; but it might nevertheless be of great interest to amplify them in a strong measure. let us, for example, suppose that a magician has found a means of increasing the intensity of gravity tenfold in his laboratory. all the conditions of life would be modified to the extent of being unrecognizable. a living being borne in this space would remain small and squat. all objects would be stocky and be spread out in width or else be shattered. viscid or semi-solid bodies, such as pitch, would rapidly spread out and take on a surface as plane and smooth as water under the conditions of gravity upon the earth. on still further increasing the gravity, we would see the soft metals behaving in the same way, and lead, copper and silver would in turn flow away. these metals, in fact, are perfectly moulded under a strong pressure, just like liquids, through the simple effect of the attraction of the earth applied to all their molecules. upon causing an adequate attractive force to act upon the molecules of metals they will be placed under conditions analogous to those to which they are submitted in strong presses or in the mills that serve for coining money. the sole difference consists in the fact that the action of gravity is infinitely more regular, and purer, from a physical standpoint, than that of the press or coining mill. through very simple considerations, we thus reach the principle which was enunciated, we believe, by the illustrious stokes, that our idea of solid and liquid bodies is a necessary consequence of the intensity of gravity upon the earth. upon a larger or smaller planet, a certain number of solid bodies would pass to a liquid state, or inversely. let us return to the cyclostat. in default of gravity, centrifugal force gives us a means of realizing certain conditions that we would find in the laboratory of our magician. the cyclostat permits us to observe what is going on in that laboratory without submitting ourselves to forces that might cause us great annoyance. we have hitherto been content to put poor frogs therein and study upon them the effect of the central anæmia and peripheral congestion produced on their organism by the unrestrained motion of the liquids carried along by centrifugal force. the results, it seems, have proved very curious.--_la nature_. * * * * * mercury weighing machine. we illustrate herewith a novel type of weighing machine. hitherto the weighing machines in common use have either been designed with some kind of steelyard apparatus, upon which weights could be moved to different distances from a fixed fulcrum, or springs have been so applied as to be compressed to different degrees by different weights put upon the scale pan, or table, of the machine. in other instances more complicated mechanism is used, and various movable counterpoises are usually required in order to balance the moving parts of the machine. [illustration] the type of machine which we now illustrate has been recently brought out by mr. g.e. rutter, and the system has given very satisfactory results with platform weighing machines. the engraving illustrates a form of balance which may be applied to strength testing machines, or for any work where an apparatus of the type of a salter's balance would be of use. it is simple in construction, and consists of a tube a closed at the bottom and forming a reservoir for mercury. the body which it is required to weigh is hung upon the hook b carried by the crossbar c, which is connected by rigid rods to the upper part of the tube, and by means of the internal rods d is attached to the cross head e, which works freely inside the tube a. the top part of the tube is, as will be clearly understood from the illustration, cut away to allow of the descent of the rods. to the cross head e is attached the piston f, which may be made of wood or of a hollow metal tube closed at the end, or other suitable material. it will be easily understood that when a weight is hung upon the hook b, the piston f is caused to descend into the mercury which rises in the annular space between the piston and the tube. the weight of the volume of displaced mercury is proportional to the weight of the body hung upon the hook, and the buoyancy of the piston in the mercury forms the upward force which balances the downward pull of gravity. when the apparatus is at rest the piston f descends into the mercury to such a distance as will balance the weight of the rods, hook, and piston itself. if, now, the cross bar g, provided with a pointer h, be fixed to the rods, it should at that time register zero, upon the scale j fixed to the outside of the tube, and as the descent of the piston into the mercury is directly proportional to the weight of the body attached to the hook b, the divisions of the scale will all be equal. it will thus be seen that the apparatus is extremely simple in theory, and it only remains to construct it in such a form that the mercury may not easily be spilt in moving the instrument from place to place. this is effected by causing the cross head e to fill the tube while working freely therein, and a small valve is arranged to allow for the passage of air. the cross bar g can be regulated upon the rods by means of set screws.--_industries._ * * * * * reefing sails from the deck. while this method may be applied to topsails and top-gallant-sails, i especially apply it to courses, which, being so difficult to reef the old way, may by this method be reefed from the deck in a few minutes. after several years of trial by myself and others, on voyages around cape horn under all circumstances of weather, of sleet and snow, this method has always given the utmost satisfaction. [illustration: reefing sails from the deck. front view. rear view.] the average time required for reefing and setting was noted for five years, being seven and one-half minutes. this trial was made on a mainsail, the yard being seventy-one feet long, and reefyard sixty-six feet long, eleven inches diameter at center and nine at yard-arms. by reference to the drawing it will be seen that it is not necessary to have clewgarnets or buntlines in reefing. the operation is performed by easing of the sheet and hauling the lee reef-tackle first, also the midship reef tackle. when the yardarm of the reefspar is up at the lee side, the sail cannot sag to leeward when the tack is eased away. now haul the weather reef-tackle likewise midship, snug up to the yard, belay all down the tack, and sheet aft. as all the reef-tackles lead to the slings of the yard, there is no impediment in swinging the yard when the reef-tackles are taut and belayed. the slack sail will not chafe, as it remains quiet, but if so desired may be stopped up at leisure with only a few hands with stops provided for that purpose. in case of a sudden squall the sail may be hauled up the usual way. the buntlines will draw the part of the sail below the reef well up on the part above the reefyard, and remain becalmed, while the weight of the reefspar will prevent any slatting or danger of losing the sail any more than any other sail clewed up. in case there is steam power at hand, all three reef-tackles may be hauled simultaneously, easing sheet and tack sufficiently to let the wind out of the sail without shaking. there are other advantages gained by this method; while its essentials are positive, quick reefing from the deck in all weathers, it is also better reefed than by the old method. for by this new method the sail is not strained or torn, and the sail will wear longer, not being subject to such straining. it may be carried longer, as the spar supports the sail like a band, especially an old sail. this method does not interfere with the use of the so called midship-tack, but change of putting on bands, from the leech of the sail at the reef to the center tack would be necessary. the weight of the spar may be considered by some as objectionable, (an old argument against double-topsail yards). the spar used for the reef may be about one-half the diameter of the yard on which it is to be used. such critics do not consider that a crew of men aloft on the yard are several times heavier than such a spar. l.k. morse. rockport, me., oct. , . * * * * * a new process for the bleaching of jute. by messrs. leykam and tosefothal. jute is well known as a very cheap fiber, and its employment in textile industry is consequently both extensive and always increasing. accompanying this increase is a corresponding one in the amount of old waste jute, which can be employed for the manufacture of paper. up to the present time, only very little use has been made of jute for the manufacture of thread and the finer fabrics, because the difficulty of bleaching the fiber satisfactorily has proved a very serious hindrance to its improvement by chemical means. all the methods hitherto proposed for bleaching jute are so costly that they can scarcely be made to pay; and, moreover, in many cases, the jute is scarcely bleached, and loses considerably in firmness and weight, owing to the large quantities of bleaching agents which have to be applied. in consequence of this difficulty, the enormous quantities of jute scraps, which are always available, are utilized in paper making almost entirely for the production of ordinary wrapping paper, which is, at the best, of medium quality. in the well known work of hoffmann and muller, the authors refer to the great difficulty of bleaching jute, and therefore recommend that it be not used for making white papers. messrs. leykam and tosefothal have succeeded in bleaching it, and rendering the fiber perfectly white, by a new process, simple and cheap (which we describe below), so that their method can be very advantageously employed in the paper industry. the jute fiber only loses very little of its original firmness and weight; but, on the other hand, gains largely in pliability and elasticity, so that the paper made from it is of great strength, and not only resists tearing, but especially crumpling and breaking. the jute may be submitted to the process in any form whatever, either crude, in scraps, or as thread or tissue. the material to be bleached is first treated with gaseous chlorine or chlorine water, in order to attack the jute pigment, which is very difficult to bleach, until it takes an orange shade. after having removed the acids, etc., formed by this treatment, the jute is placed in a weak alkaline bath, cold or hot, of caustic soda, caustic potash, caustic ammonia, quicklime, sodium or potassium carbonate, etc., or a mixture of several of these substances, which converts the greatest part of the jute pigment, already altered by the chlorine, into a form easily soluble in water, so that the pigment can be readily removed by a washing with water. after this washing the jute can be bleached as easily as any other vegetable fiber in the ordinary manner, by means of bleaching powder, etc., and an excellent fibrous material is obtained, which can be made use of with advantage in the textile and paper industries. the application of the process may be illustrated by an example: one hundred kilos. of waste jute scraps are first of all treated in the manner usually employed in the paper industry; per cent. of quicklime is added, and they are treated for hours at a pressure of ½ atmospheres. the scraps are then freed from water by means of a hydro-extractor, or a press, and finally saturated with chlorine in a gas chamber for hours or less, according to the requirements of the case. every kilos. of jute requires kilos. of hydrochloric acid ( ° b.) and kilos. of manganese peroxide ( - per cent.). the jute then takes an orange color, and is subsequently washed in a tank, a kilo. of caustic soda being added per kilos. of jute; this amount of alkali is sufficient to dissolve the pigment, which colors the water flowing from the washer a deep brown. after washing, the jute can be completely bleached by the use of - kilos. of bleaching powder per kilos. of jute.--_mon. de la teinture_. * * * * * the independent--storage or primary battery--system of electric motive power.[ ] [footnote : abstract of a paper read before the american streel railway association, oct. , .] by knight neftel. owing to a variety of causes, the system which was assigned to me at the last convention to report on has made less material progress in a commercial way than its competitors. primary batteries. so far, primary batteries have been applied only to the operation of the smallest stationary motors. their application in the near future to traction may, i think, be entirely disregarded. were it not a purely technical matter, it might be easily demonstrated, with our knowledge of electro-chemistry, that such an arrangement as an electric primary battery driving a car is an impossibility. in view of the claims of certain inventors, i regret to be obliged to make so absolute a statement; but the results so far have produced nothing of value. secondary batteries. the application of secondary or storage batteries to electrical traction has been accomplished in a number of cities, with a varying amount of success. roads equipped by batteries have now been sufficiently long in operation to allow us to draw some conclusions as to the practical results obtained and what is possible in the near future. the advantages which have been demonstrated on madison avenue, in new york; dubuque, iowa; washington, d.c., and elsewhere, may be summarized as follows: _first_. the independent feature of the system. the cars independent of each other, and free from drawbacks of broken trolley wires; temporary stoppages at the power station; the grounding of one motor affecting other motors, and sudden and severe strains upon the machinery at the power station, such as frequently occur in direct systems; the absence of all street structures and repairs to the same, and the loss by grounds and leakages, are also very considerable advantages, both as to economy and satisfactory operation. _second_. the comparatively small space required for the power station. each car being provided with two or more sets of batteries, the same can be charged at a uniform rate without undue strain on the machinery of the power station, and as it can be done more rapidly than the discharge required for the operation of the motors, a less amount of general machinery is necessary for a given amount of work. another and important advantage of the system is the low pressure of the current used to supply the motors, and the consequent increased durability of the motor, and practically absolute safety to life from electrical shock. it has been demonstrated also that the cars can be easily handled in the street; run at any desired speed, and reversed with far more safety to the armature of the motor than in the direct system. the increased weight requires simply more brake leverage. the modern battery, improved in many of its details during the last year, is still an unknown quantity as to durability. there is the same doubt concerning this as there was at the time incandescent lamps were first introduced. at that time some phenomenal records were made by lamps grouped with other lamps. similarly, some plates appeared to be almost indestructible, while others, made practically in the same manner, deteriorate within a very short time. it is, consequently, very difficult to exactly and fairly place a limit on the life of the positive plates as yet. speaking simply from observation of a large number of plates of various kinds, i am inclined to put the limit at about eight months; though it is claimed by some of the more prominent manufacturers--and undoubtedly it is true in special cases--that entire elements have lasted ten months, and even longer. it must be remembered, however, that the jolting and handling to which these batteries are subjected, in traction work, increases the tendency to disintegrate, buckle and short circuit, and that the record for durability for this application can never be the same as for stationary work. a serious inconvenience to the use of batteries in traction work is the necessary presence of the liquid in the jars. this causes the whole equipment to be somewhat cumbersome, and unless arranged with great care, and with a variety of devices lately designed, a source of considerable annoyance. the connections between the plates, which formerly gave so much trouble by breaking off, have been perfected so as to prevent this difficulty, and the shape of the jars has been designed to prevent the spilling of the acid while the car is running. the car seats are now practically hermetically sealed, so that the escaping gases are not offensive to the passengers. the handling of the batteries is an exceedingly important consideration. many devices have been invented to render this easy and cheap. i have witnessed the changing of batteries in a car, one set being taken out and a charged set replaced by four men in the short space of three minutes. this is accomplished by electrical elevators, which move the batteries opposite the car, and upon the platforms of which the discharged elements are again charged. the general conclusions which the year's experience and progress have afforded us an opportunity to make may be summarized as follows: storage battery cars are as yet applicable only to those roads which are practically level; where the direct system cannot be used, and where cable traction cannot be used; and applicable to those roads only at about the same cost as horse traction. i feel justified in making this statement in view of the guarantees which some of the more prominent manufacturers of batteries are willing to enter into, and which practically insure the customer against loss due to the deterioration of plates: leaving the question of the responsibility of the company the only one for him to look into. * * * * * on the elimination of sulphur from pig iron.[ ] [footnote : paper read before the iron and steel institute.] by j. massenez, hoerde. if in the acid and the basic bessemer processes the molten pig iron is taken direct to the converter from the blast furnace, there is the disadvantage that the running of the individual blast furnaces can hardly ever be kept so uniform as it is desirable should be the case in order to secure regularity in the converter charges. in the manufacture of bessemer steel the variable proportions of silicon and of carbon here come chiefly under consideration, while in the basic process it is chiefly the varying proportions of silicon and of sulphur; and in cases where either ores containing variable percentages of phosphorus, or puddle slags, are treated, the varying proportion of phosphorus has also to be considered. this disadvantage of the irregular composition of the individual blast furnace charges is obviated in a simple and effective manner by w.r. jones's mixing process. in this as much pig iron from the various blast furnaces of a works as is sufficient for a large number of bessemer charges, say from seven to twelve charges, or, in other words, from to tons of pig iron, is placed in a mixing vessel. only a portion of pig iron placed in the mixer is taken for further treatment for steel, while new supplies of pig iron are brought from the blast furnace. in this way homogeneity sufficient for practical purposes is obtained. in the treatment of phosphoric pig iron, which is employed in the production of basic steel, it is, however, not sufficient merely to conduct the molten pig iron in large quantities to the converter in a mixed condition, but the problem here is to render the proportion of sulphur also independent of the blast furnace process to such an extent that the proportion of sulphur in the finished steel is so low that the quality of the steel is in no way influenced by it. the question of desulphurization has, especially of late years, become of the utmost importance, at any rate for the iron industry of the continent. by the great strike of , the german colliers have succeeded in greatly improving their wages; and with this increase in wages not only is there a distinct diminution in the amount of coal wrought, but, unfortunately, the coal produced since then is raised in a much less pure condition than was formerly the case. consequently the proportion of sulphur in the coke has considerably increased. whereas formerly this proportion did not exceed one per cent., it has now in many cases risen to per cent.; so that an unpleasant ratio exists between the wages of the workmen and the amount of sulphur in the coal raised. it is therefore not remarkable that, even when ores fairly free from sulphur are treated, it easily happens that a sulphureted pig iron is obtained. in order to effect satisfactory desulphurization, attention has been bestowed on the fact that iron sulphide is converted by manganese into manganese sulphide and iron. if sulphureted pig iron, poor in manganese, is added in a fluid condition to manganiferous molten pig iron, poor in sulphur, the metal is desulphurized, and a manganese sulphide slag is formed. it may be urged that it does not seem necessary to effect the desulphurization by means of the reaction of the manganese and iron sulphide outside of the blast furnace, as it is possible, by suitably directing the blast furnace, by the employment of manganiferous ores or highly basic slag, so to desulphurize the iron in the blast furnace itself that it would be unnecessary further to lower the percentage of sulphur. every blast furnace manager, however, will have observed that, even with every precaution in the blast furnace practice, pig iron will often be obtained with so high a percentage of sulphur as to render it useless for the bessemer acid or basic processes. if the desulphurization in the blast furnace is carried sufficiently far, it is always necessary to work the furnace hot, and thus to obtain hotter iron than is desirable for further treatment in the converter. on the other hand, the method of further desulphurization outside the blast furnace, described in this paper, presents the double advantage that part of the blast furnace can be kept cooler, and thus lime and coke be saved, and that there is a certainty that no red-short charges are obtained in the treatment in the converter, while the pig iron passes to the converter at a suitable temperature. [illustration: figs. through ] a further advantage presented by the direct process described in this paper is that the bessemer works is independent of the time at which the individual blast furnaces are tapped, as the pig iron required for the bessemer process can be taken at any moment from the desulphurizing plant. in hoerde, where the mixing and desulphurizing process has for a considerable time been regularly in use, it has been found that all the chief difficulties formerly encountered in the method of taking the fluid pig iron direct from the various blast furnaces to the converter have been obviated. at hoerde the mixing and desulphurizing plant shown in the accompanying engravings is employed. this apparatus holds tons of pig iron. it is, however, advisable to have an apparatus of greater capacity, say tons. the apparatus has the shape of a converter, and the hydraulic machinery by which it is moved is simple and effective. an hydraulic pressure of eight atmospheres is sufficient to set it in motion. the vessel is provided with a double lining of firebricks of the same quality as those used for the lining of blast furnaces. this lining is gradually attacked only along the slag line, and does not require repair until it has been in use for some six weeks. further repairs are then necessary every three weeks. only the few courses of spoilt bricks are renewed, and for the repairs, including the cooling of the vessel, a period of two or three days is required. at the end of the week the vessel is kept filled, so that its contents suffice for the last charge to be blown on saturday. on sunday night the vessel is again filled. the consumption of manganese is very low; theoretically, it is the quantity required for the formation of manganese sulphide, and in practice it has been found that this amounts to about . per cent. the proportion of manganese which the desulphurized pig iron coming from the vessel should contain is best kept at about . per cent. in order to render the desulphurization as complete as possible. thus, a mean proportion of . per cent. of manganese in the pig iron passing into the vessel is more than sufficient to effect a thorough desulphurization. indeed, to . per cent. of manganese is sufficient to effect a satisfactory desulphurization. for the extent of the removal of the sulphur, the temperature and the duration of the reaction are of importance. it has been found that if highly sulphureted pig iron is poured from the blast furnace into the desulphurizing vessel, fifteen to twenty minutes are sufficient to effect the desulphurization requisite for the steel process. the part played by the duration of the process is seen from the results obtained with the last charges, if the vessel is emptied at the end of the week without fresh pig iron being added from the blast furnace. if, for example, tons of pig iron with . per cent. of sulphur remain in the vessel, the proportion of sulphur with the last charges falls to . per cent. the iron in the vessel remains sufficiently fluid for several hours. when necessary, a little wood is thrown in. it has been found quite unnecessary to obtain heat by passing and burning a current of gas above the bath of metal. a number of results, showing the separation of sulphur at the hoerde works, was published a few months ago[ ] by professor p. tunner, one of our honorary members. [footnote : "oesterreichische zeitschrift fur berg und huttenwesen," , no. .] the totals represent, respectively, , kilogrammes of pig iron and , kilogrammes of sulphur. thus, from , kilogrammes of pig iron there has been eliminated , - , = , kilogrammes of sulphur, or, in other words, . per cent. the proportion of sulphur in the slags rises with that in the iron from the blast furnace to per cent., an inappreciable portion of the sulphur of the slag being oxidized to sulphurous anhydride by access of air. an analysis of the slag yielded the following results: per cent. sulphur . manganese . phosphoric anhydride . iron . bases . an analysis of an average sample gave: per cent. manganese sulphide . manganous oxide . ferrous oxide . silica . alumina . lime . magnesia . the great convenience and certainty presented by the method described in this paper will in all probability lead to its general adoption. as a matter of fact, several works are now occupied with the installation of this mixing and desulphurizing plant. * * * * * on the occurrence of tin in canned food. by h.a. weber, ph.d. the following investigation of the condition of foods packed in tin cans was prompted by an alleged case of poisoning, which occurred at mansfield, ohio, in april, . a man and woman were reported to the writer as having been made sick by eating pumpkin pie made from canned pumpkin. the attending physician pronounced the case one of lead poisoning. the wholesale dealer from whose stock the canned pumpkin originally came, procured a portion of the same at the house where the poisoning occurred, and sent it to the writer for examination. the results of the examination as reported in serial no. , below, showed that the canned pumpkin contained an amount of stannous salts equivalent to . maximum doses and . minimum doses of stannous chloride per pound. on being notified of this fact, the dealer sent a can of the same brand of pumpkin from his stock. the inner coating of the can was found to be badly eroded, and upon examination, as reported in serial no. , below, one pound of the pumpkin contained tin salts equivalent to maximum and minimum doses of stannous chloride. the unexpected large amount of tin salts in such an insipid article as canned pumpkin, and the claimed ill effects of the consumption of the same, suggested the advisability of extending the investigation to other canned goods in common use. accordingly a line of articles was purchased in open market as sold to consumers, no pains being taken to procure old samples. the collection embraced fruits, vegetables, fish and condensed milk. with the exception of the condensed milk, every article examined was contaminated with salts of tin. in most cases the amount of tin salts present was so large that there can be no doubt of danger to health from the consumption of the food, especially if several kinds are consumed at the same meal. method. the method employed in the determination of the tin was simply as follows: the contents of each can were emptied into a large porcelain dish, and the condition of the inner coating of the can noted. after thoroughly mixing the contents, fifty grammes were weighed off and incinerated in a porcelain dish of suitable size. the residue was treated with a large excess of concentrated hydrochloric acid, evaporated to dryness, moistened with hydrochloric acid, water was added, and the mass was filtered and washed, the insoluble matter being all washed upon the filter. after drying the filter with its contents, the whole was again incinerated in a porcelain dish and the residue treated as before. the solution thus obtained was properly diluted and saturated with hydrogen sulphide. after standing about twelve hours in a covered beaker the precipitate was filtered off and the tin weighed as stannic oxide. results of examination. _serial no. ._--sample of canned pumpkin, received of f.a. derthick, april , , sent by albert f. remy & co., mansfield, ohio. pie made from it supposed to have made a man and woman sick. the attending physician pronounced the case one of lead poisoning. per cent. tin dioxide with trace of lead . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . _serial no. ._--sample of canned pumpkin, received of edward bethel, june , . labeled: choice pie pumpkin, packed at salem, columbiana county, ohio, by g.b. mcnabb, sent by a.f. remy & co., mansfield, ohio. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses maximum doses can eroded. _serial no. ._--sample of canned pumpkin, bought of t.b. vaure, july , . labeled: belpre pumpkin, golden. george dana & sons, belpre, ohio. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can eroded. _serial no. ._--sample of canned hubbard squash, bought of t.b. vaure, july , . labeled: ladd brand, l. ladd, adrian, michigan. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can badly eroded. _serial no. ._--sample of canned tomatoes, bought of t.b. vaure, july , . labeled: extra fine tomatoes. blue label. curtice bros. co., rochester, n.y. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . inner coating eroded. _serial no. ._--sample of canned tomatoes, bought of t.b. vaure, july , . labeled: fresh tomatoes, curtice bros. co., rochester, n.y. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can eroded. _serial no. ._--sample of canned peas, bought of t.b. vaure, july , . labeled: petites pois, p. emillien, bordeaux. per cent. copper oxide . grains per pound . equivalent to copper sulphate . tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . no visible erosion. _serial no. ._--sample of canned mushroom, bought of t.b. vaure, july , . labeled champignons de choix. boston fils. paris. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . inner coating highly discolored. _serial no. ._--sample of canned blackberries, bought of t.b. vaure, july , . labeled: lawton blackberries. curtice bros. co., rochester, n.y. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . inner coating eroded. _serial no. ._--sample of canned blueberries, bought of t.b. vaure, july , . labeled: blueberries. eagle brand, packed by a. & r. loggie, black brook, n.b. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can badly eroded. _serial no. ._--sample of canned salmon, bought of t.b. vaure. july , . labeled: best fresh columbia river salmon, eagle canning co., astoria clatsop co., oregon. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . inner coating eroded. _serial no. ._--sample of canned pears, received of mr. edward bethel, july , . labeled: bartlett pears. solan's brand, packed in solano co., california. juice. fruit. per ct. per ct. tin dioxide . . grains per pound . . equivalent to stannous chloride . . minimum doses . . maximum doses . . can eroded. _serial no. ._--sample of canned peaches, received of edward bethel, july . . labeled: peaches, wm. maxwell, baltimore, u.s.a. juice. fruit. per ct. per ct. tin dioxide . . grains per pound . . equivalent to stannous chloride . . minimum doses . . maximum doses . . can badly eroded. _serial no. ._--sample of canned blackberries, received of edward bethel, july , . labeled: blackberries, clipper brand, wm. munson & sons, baltimore, md. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can badly eroded. _serial no. ._--sample of canned cherries, received of edward bethel, july , . labeled: red cherries, cloverdale brand, g.c. mournaw & co., cloverdale, va. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can badly eroded. _serial no. ._--sample of canned pumpkin, received of edward bethel, july , . labeled: royal pumpkin, urbana canning co., urbana, o. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses. . can eroded. _serial no. ._--sample of canned baked sweet potatoes, received of edward bethel, july , . labeled: tennessee baked sweet potatoes, capital canning co., nashville, tenn. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can eroded. _serial no. ._--sample of canned peas, received of edward bethel, july , . labeled: marrowfat peas, parson bros., aberdeen, maryland. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can slightly eroded. _serial no. ._--sample of string beans, received of edward bethel, july , . labeled: string beans. packed by h.p. hemingway & co., baltimore city, md. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can eroded. _serial no. ._--sample of canned salmon, received of edward bethel, july , . labeled: puget sound fresh salmon, puget sound salmon co., w.t. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can slightly eroded. _serial no. ._--sample of condensed milk, received of edward bethel, july , . labeled: borden's condensed milk. the gail borden eagle brand, new york condensed milk co., hudson street, new york. tin dioxide none. no visible erosion. _serial no. ._--sample of canned pineapples, bought of mr. brown, fifth avenue, august , . labeled: pineapples, first quality. packed by martin wagner & co., baltimore, md. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can eroded _serial no. ._--sample of canned pineapples, bought of mr. brown, fifth avenue, august , . labeled: florida pineapple, oval brand. extra quality. a booth packing co., baltimore, md. per cent. tin dioxide . grains per pound . equivalent to stannous chloride . minimum doses . maximum doses . can eroded. --_jour. amer. chem. soc_. * * * * * new process for the manufacture of chromates. by j. massignon and e. vatel. the ordinary method of manufacturing the bichromates consists in making an intimate mixture of finely pulverized chrome ore, lime in large excess, potash or soda, or corresponding salts of these two bases. this mixture is placed in a reverberatory furnace, and subjected to a high temperature, while plenty of air is supplied. during the operation the mass is constantly puddled to bring all the particles into contact with the hot air, so that all the sesquioxide of chromium of the ore will be oxidized. after the oxidation is finished, the mass is taken from the furnace and cooled; the bichromate is obtained by lixiviation, treated with sulphuric acid and crystallized. this method of manufacture has several serious objections. the authors, after research and experiment, have devised a new process, following an idea suggested by pelouze. the ore very finely pulverized is mixed with chloride of calcium or lime, or carbonate of calcium, in such proportions that all the base, proceeding from the caustic lime or the carbonate of calcium put in the mixture, shall be in slightly greater quantity than is necessary to transform into chromate of calcium all the sesquioxide of chromium of the ore, when this sesquioxide will be by oxidation changed into the chromic acid state. the chloride of calcium employed in proportion of one equivalent for three of the total calcium is most convenient for the formation of oxychloride of calcium. if the mixture is made with carbonate of lime (pulverized chalk), it will not stiffen in the air; but if lime and carbonate of calcium are employed at the same time, the mass stiffens like cement, and can be moulded into bricks or plates. the best way to operate is to mix first a part of the ore and well pulverized chalk, and slake it with the necessary concentrated chloride of calcium solution; then to make up a lime dough, and mix the two, moulding quickly. the loaves or moulds thus formed are partially dried in the air, then completely dried in a furnace at a moderate temperature, and finally baked, to effect the reduction of the carbonate of calcium into caustic lime. it is only necessary then to expose the loaves to the air at the ordinary temperature, for the oxidation of the sesquioxide of chromium will go on by degrees without any manipulation, by the action of the atmospheric air, the matter thus prepared having a sufficient porosity to allow the air free access to the interior of the mass. under ordinary conditions the oxidation will be completed in a month. the division of this work--mixing, slaking or thinning, roasting or baking, and subjection to the air--is analogous to the work of a tile or brick works. the advance of the oxidation can be followed by the appearance of the matter, which after baking presents a deep green color, which passes from olive green into yellow, according to the progress of calcium chromate formation. when the oxidation is completed, the mass contains: chromate of calcium, chloride of calcium, carbonate of lime and caustic lime in excess, sesquioxide of iron and the gangue, part of which is united with the lime. this mass is washed with water by the ordinary method of lixiviation, and there is obtained a concentrated solution containing all the chloride of calcium, and a small quantity only of chromate of calcium, the latter being about times less soluble in water. this solution can be used in the following ways: . it can be concentrated and used in preparing a new charge, the small quantity of calcium chromate present being an assistance, or: . it can be used for making chromate of lead (chrome yellow), by precipitating the calcium chromate with a lead salt; this being a very economical process for the manufacture of this color. the mass after lixiviation, being treated with a solution of sulphate or carbonate of potash or soda, will yield chromate of potash or soda, and by the employment of sulphuric acid, the corresponding bichromates. the solutions are then filtered, to get rid of the insoluble deposits, concentrated, and crystallized. if, instead of chromate or bichromate of potash or soda, chromic acid is sought, the mass after lixiviation is treated with sulphuric acid, and the chromic acid is obtained directly without any intermediate steps. this process has the following advantages: . the oxidation can be effected at the ordinary temperature, thus saving expense in fuel. . the heavy manual labor is avoided. . the loss of potash and soda by volatilization and combination with the gangue is entirely avoided. . it is not actually necessary to use rich ores; silicious ores can be used. . the intimate mixture of the material before treatment being made mechanically, the puddling is avoided, and in consequence a greater proportion of the sesquioxide of chromium in the ores is utilized.--_bull. soc. chem._ , . * * * * * a violet coloring matter from morphine. a violet coloring matter is formed, together with other substances, by boiling for hours in a reflux apparatus a mixture of morphine (seven grammes), p-nitrosodimethylaniline hydrochloride (five grammes), and alcohol ( c.c.). the solution gradually assumes a red brown color, and a quantity of tetramethyldiamidoazobenzene separates in a crystalline state. after filtering from the latter, the alcoholic solution is evaporated to dryness, and the residue boiled with water, a deep purple colored solution being so obtained. this solution, which contains at least two coloring matters, is evaporated almost to dryness, acidulated with hydrochloric acid, and then rendered alkaline with sodium hydrate, the coloring matters being precipitated and the unchanged morphine remaining in solution. the precipitate is collected on a filter, washed with dilute sodium hydrate, dried, and extracted in the cold with amyl alcohol, which dissolves out a violet coloring matter, and leaves in the residue a blue coloring matter or mixture of coloring matters. the violet coloring matter is obtained in a pure state on evaporating the amyl alcohol. its platinochloride has the formula ptcl_{ }.c_{ }h_{ }n_{ }o_{ }.hcl, and has the characteristic properties of the platinochlorides of the majority of alkaloids. the coloring matter, of which the free base has the formula-- (c_{ }h_{ }n(ch_{ })_{ })--n==(c_{ }h_{ }no_{ }) forms an amorphous mass with a bronze-like luster; it is sparingly soluble in water, freely so in alcohol, its alcoholic solution being strongly dichroic; its green colored solution in concentrated sulphuric acid becomes successively blue and violet on dilution with water; it dyes silk, wool, and gun cotton, but is not fast to light. morphine violet is the first true coloring matter obtained from the natural alkaloids, the morphine blue of chastaing and barillot (compt. rend., , ) not being a coloring matter properly so called. --_p. cazeneuve, bull. soc. chim._ * * * * * liquid blue for dyeing. the new liquid blue of m. dornemann is intended to avoid the formation of clots, etc., which lead to irregularity in shade, if not to the formation of spots on the textile. in addition to accomplishing this end, the process is accelerated by subjecting the blue to a previous treatment. in this preliminary treatment of the blue, the object is to remove the sulphur which retards the solution of the color. the liquid is prepared as follows: the pigment, previously dried at ° c., is crushed and finely ground, and contains about per cent. of coloring matter; to this is added per cent. of water. to this mixture, or slurry, the inventor adds an indefinite quantity of glucose and glycerine of ° b., having a specific gravity of . . it is then ready for use.--_le moniteur de la teinture_. * * * * * a new catalogue of valuable papers contained in scientific american supplement during the past ten years, sent _free of charge_ to any address. munn & co., broadway, new york. * * * * * the scientific american architects and builders edition. $ . a year. single copies, cts. this is a special edition of the scientific american, issued monthly--on the first day of the month. each number contains about forty large quarto pages, equal to about two hundred ordinary book pages, forming, practically, a large and splendid magazine of architecture, richly adorned with _elegant plates in colors_ and with fine engravings, illustrating the most interesting examples of modern architectural construction and allied subjects. a special feature is 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[illustration] scientific american supplement no. new york, july , scientific american supplement. vol. xxxii, no. . scientific american established scientific american supplement, $ a year. scientific american and supplement, $ a year. * * * * * table of contents. i. botany.--cocos pynaerti.--a new dwarf growing palm.-- illustration. ii. chemistry.--the application of electrolysis to quantitative analysis.--by charles a. kohn, b.sc., ph.d.--applicability of these methods to poison determinations. iii. civil engineering.--the kioto-fu canal in japan.--a japanese canal connecting the interior of the country with the sea.-- illustrations. the iron gates of the danube.--an important engineering work, opening a channel in the danube.-- illustration. the new german ship canal.--connection of the baltic with the north sea.--completion of this work.-- illustration. transit in london, rapid and otherwise.--by james a. tilden. --a practical review of london underground railroads and their defects and peculiarities. iv. electricity.--an electrostatic safety device.--apparatus for grounding a circuit of too high potential.-- illustration. experiments with high tension alternating currents.--sparking distance of arc formed by a potential difference of , volts. -- illustration. laying a military field telegraph line,--recent field trials in laying telegraph line in england.-- illustrations. some experiments on the electric discharge in vacuum tubes. --by prof. j.j. thomson, m.a., f.r.s.--interesting experiments described and illustrated.-- illustrations. the electrical manufacture of phosphorus.--note upon a new english works for this industry. v. geography.--the mississippi river.--by jacques w. redway. --an interesting paper on the great river and its work and history. vi. mechanical engineering.--how to find the crack.-- note on a point in foundry work. riveted joints in boiler shells.--by william barnet le van.--continuation of this practical and important paper. -- illustrations. vii. medicine and hygiene.--influence of repose on the retina. --important researches on the physiology of the eye. the relation of bacteria to practical surgery.--by john b. roberts, a.m., m.d.--a full review from the surgeon's standpoint of this subject, with valuable directions for practitioners. viii. mineralogy.--precious and ornamental stones and diamond cutting.--by george frederick kunz.--an abstract from a recent census bulletin, giving interesting data. ix. mining engineering.--mine timbering.--the square system of mine timbering as used in this country in the pacific coast mines and now introduced into australia.-- illustration. x. miscellaneous.--freezing mixtures.--a list of useful freezing mixtures. sun dials.--two interesting forms of sun dials described. -- illustrations. the undying germ plasm and the immortal soul.--by dr. r. von lendenfeld.--a curious example of modern speculative thought. xi. naval engineering.-the new british battle ship empress of india.--a first class battle ship recently launched at pembroke dockyard. xii. technology.--composition of wheat grain and its products in the mill.--a scientific examination of the composition of wheat and its effect on mill products. fast and fugitive dyes.--by prof. j.j. hammel.--practical notes from the dyer's standpoint upon coloring agents. * * * * * mine timbering. the square system of timbering, in use in most of our large mines on the pacific coast, was first introduced in australia by mr. w.h. patton, who adopted it in the broken hill proprietary mines, although it does not seem to be so satisfactory to the people there as to our miners, who are more familiar with it. the accompanying description and plans were furnished by mr. patton to the report of the secretary of mines for victoria: "the idea is supposed to have originated in the german mines, but in a crude form. it was introduced among the mines of the pacific coast of america some years ago, by a gentleman named diedesheimer. its use there is universal, and experience has evolved it from the embryo state to its present perfection. the old system and its accompanying disadvantages are well known. a drive would be put in for a certain distance, when it had to be abandoned until it could be filled up with waste material and made secure. this process entailed much expense. the stuff had first to be broken on the surface, then sent below, trucked along the drives, and finally shoveled into place. ventilation was impaired and the drives were filled with dust. the men worked in discomfort, and were not in a condition to perform a full measure of labor. under the system as adopted in the proprietary mine, these disadvantages disappear. the cost is one-third less, ventilation is perfect, and every portion of the faces are accessible at all times. sawn timber is used throughout; the upright and cross pieces are inches by inches, and stand feet inches apart; along the course of the drive, the cross pieces are five feet in length, and the height of the main drives and sill floor sets are feet inches in the clear. in blocking out the stopes, the uprights are feet inches, just one foot shorter than those in the main drives. the caps and struts are of the same dimensions and timber as the sill floor. the planks used as staging are inches by ½ inches; they are moved from place to place as required, and upon them the men stand when working in the stopes and in the faces. a stope resembles a huge chamber fitted with scaffolding from floor to roof. the atmosphere is cool and pure, and there is no dust. stage is added to stage, according as the stoping requires it, and ladders lead from one floor to the other; the accessibility to all the faces is a great advantage. if, while driving, a patch of low grade ore is met with, it can be enriched by taking a higher class from another face, and so on. any grade can be produced by means of this power of selection. opinions have been expressed that this system of timbering is not secure, and that pressure from above would bring the whole structure down in ruins. but an opinion such as this is due to miscomprehension of the facts. if signs of weakening in the timbers become apparent, the remedy is very simple. four or more of the uprights are lined with planks, and waste material is shot in from above, and a strong support is at once formed, or if signs of crushing are noticed, it is possible to go into the stope, break down ore, and at once relieve the weight." [illustration: the square system of timbering in mines.] * * * * * transit in london, rapid and otherwise.[ ] [footnote : abstract from a paper read before the boston society of engineers, in april, .] by james a. tilden. the methods of handling the travel and traffic in the city of london form a very interesting subject for the study of the engineer. the problem of rapid transit and transportation for a city of five millions of inhabitants is naturally very complicated, and a very difficult one to solve satisfactorily. the subject may be discussed under two divisions: first, how the suburban travel is accommodated, that is, the great mass of people who come into the business section of the city every morning and leave at night; second, how the strictly local traffic from one point to another is provided for. under the first division it will be noted in advance that london is well provided with suburban railroad accommodation upon through lines radiating in every direction from the center of the city, but the terminal stations of these roads, as a rule, do not penetrate far enough into the heart of the city to provide for the suburban travel without some additional methods of conveyance. the underground railroad system is intended to relieve the traffic upon the main thoroughfares, affording a rapid method of transportation between the residential and business portions, and in addition to form a communicating link between the terminals of the roads referred to. these terminal stations are arranged in the form of an irregular ellipse and are eleven in number. one of the most noticeable features of the underground system in london is that it connects these stations by means of a continuous circuit, or "circle," as it is there called. the line connecting the terminal stations is called the "inner circle." there is also an extension at one end of this elliptical shaped circle which also makes a complete circuit, and which is called the "middle circle," and a very much larger circle reaching the northern portions of the city, which is called the "outer circle." the eastern ends of these three circles run for a considerable distance on the same track. in addition to this the road branches off in a number of directions, reaching those parts of the city which were not before accommodated by the surface roads, or more properly the elevated or depressed roads, as there are no grade crossings. with regard to the accommodation afforded by this system: it is a convenience for the residents of the western and southern parts of london, especially where they arrive in the city at any of the terminal stations on the line of the "circle," as they can change to the underground. they can reach the eastern end of the "circle," at which place is located the bank and the financial section of london, in a comparatively short time. for example, passengers arriving at charing cross, victoria or paddington stations, can change to the underground, and in ten, fifteen and thirty minutes respectively, reach the mansion house or cannon street stations, which are the nearest to the bank of england. in a similar manner those arriving at euston, st. pancras or king's cross on the northern side of the "circle," can reach broad street station in ten or fifteen minutes, which station is nearest the bank on that side of the "circle." in a number of cases the underground station is in the same building or directly connected by passages with the terminal stations of the roads leading into the city. examples of this kind would be such stations as cannon street, victoria or paddington. they are not, however, sufficiently convenient to allow the transference of baggage so as to accommodate through passengers desiring to make connection from one station to another across the city. hand baggage only is carried, about the same as it is on the elevated road in new york. the method of cross town transfer, passengers and baggage, is invariably done by small omnibuses, which all the railroads maintain on hand for that special purpose. a very large proportion of the travel, however, if not the largest, is obtained by direct communication by means of the "circle" on branch lines with the various residential portions of north, west and south london. approximately on the underground railroad the fare is one cent per mile for third class, one cent and a half for second class, and two cents for first class, but no fare is less than a penny, or two cents. omnibus fares in some instances are as low as a penny for two miles. this is not by any means the rule, and is only to be found on competing lines. the average fare would be a penny a mile or more. the fares on the main lines which accommodate the suburban traffic are somewhat higher than on the underground, perhaps per cent. more. in every case, on omnibus, tram cars or railroads, the rates are charged according to distance. the system such as in use on our electric, cable and horse cars and on the elevated road in new york, of charging a fixed fare, is not in use anywhere. the ticket offices of the underground roads are generally on a level with the street. in some instances both the uptown and downtown trains are approached from one entrance, but generally there is an entrance at either side of the railroad, similar to the elevated railroad system. in purchasing a ticket, the destination, number of the class, and whether it is a single or return ticket have to be given. the passenger then descends by generally well lighted stairways to the station below, and his ticket is punched by the man at the gate. he then has to be careful about two things; first, to place himself on that part of the platform where the particular class which he wishes to take stops, and secondly, to get on to the right train. in the formation of the train the first class coaches are placed in the center, the second and third class respectively at the front and rear end. there are signs which indicate where passengers are to wait, according to the class. there is a sign at the front end of the engine, which to those initiated sufficiently indicates the destination of the train. the trains are also called out, and at some stations there is an obscure indicator which also gives the desired information. the stations are from imperfectly to well lighted, generally from daylight which sifts down from the smoky london atmosphere through the openings above. the length of the train averages about eight carriages of four compartments, each compartment holding ten persons, making a carrying capacity of passengers. the equipment of the cars is very inferior. the first class compartments are upholstered and cushioned in blue cloth, the second class in a cheaper quality, while most of the third class compartments have absolutely nothing in the way of a cushion or covering either on the seat or back, and are little better than cattle pens. the width of the compartment is so narrow that the feet can easily be placed on the opposite seat, that is, a very little greater distance than would be afforded by turning two of our seats face to face. the length of the compartment, which is the width of the car, is about a foot and a half less than the width of our passenger cars, about equal to our freight cars. each compartment is so imperfectly lighted by a single lamp put into position through the top of the car that it is almost impossible to read. the length of time which a train remains at a station is from thirty to forty seconds, or from three to four times the length of time employed at the new york elevated railroad stations. the reason for this is that a large proportion of the doors are opened by passengers getting in or out, and all these have to be shut by the station porter or guard of the train before the train can start. if the train is crowded one has to run up and down to find a compartment with a vacant seat, and also hunt for his class, and as each class is divided into smoking and non-smoking compartments, making practically six classes, it will be observed that all this takes time, especially when you add the lost time at the ticket office and gate. the ventilation of the tunnels and even the stations is oftentimes simply abominable, and although the roads are heavily patronized there is a great amount of grumbling and disfavor on this account. the platforms of the stations are flush with those of the cars, so that the delay of getting in or out is very small, but the doors are so low that a person above the average height has to stoop to get in, and cannot much more than stand upright with a tall hat on when he is once in the car. the monitor roof is unknown. the trains move with fair speed and the stations are plainly and liberally marked, so that the passenger has little difficulty in knowing when to get out. there are two signs in general use on english railroads which are very simple and right to the point, namely, "way out" and "way in," so that when a passenger arrives at a station he has no question how to get out of it. the ticket is given up as the passenger leaves the station. there is nothing to prevent a passenger with a third class ticket getting into a first class compartment excepting the ominous warning of shillings fine if he does so, and the liability of having his sweet dreams interrupted by an occasional inspector who asks to see the denomination of his ticket. all compartments intended for the use of smokers are plainly marked and are to be found in each class. almost the entire part of the railroads within the thickly settled portions of the city run in closed tunnels. outside of this they frequently run in open cuttings, and still further out they run on to elevated tracks. with regard to the equipment of the suburban or surface lines not belonging to the underground system the description is about the same. the cars are generally four compartments long and sometimes not exceeding three. they are coupled together with a pair of links and fastened to the draw bar on one car and the other thrown over a hook opposite and brought into tension by a right and left hand screw between the links. this is obviously very inconvenient for shunting purposes, especially as the cars are not provided with hand brakes and no chance to get at them if there were any. consequently it appears that when a train is made up it stays so for an indefinite period. a load of passengers is brought into the station and the train remains in position until it is ready to go out. as the trains run very frequently this appears to be a very economical arrangement, as no shunting tracks are needed for storage. the engine which brings the train in of course cannot get out until the train goes out with the next load. turn tables for the locomotives are but very little used, as they run as double enders for suburban purposes. in conclusion it will be safe to say that the problem of rapid transit for a city as large as london is far from solved by the methods described. although there are a great many miles of underground lines and main lines, as they have been called throughout the paper, and although grade crossings have been entirely abolished, allowing the trains to run at the greatest speed suitable to their frequency, still there are a great many sections which have to depend entirely upon the omnibus or tram car. the enormous expense entailed by the construction of the elevated structures can hardly be imagined. we have but one similar structure in this country, which is that running from the schuylkill river to broad street station, in philadelphia. the underground system is even more expensive, especially in view of the tremendous outlay for damages. this goes to show that money has not been spared to obtain rapid transit. after all, the means to be depended upon when one desires to make a rapid trip from one part of the city to another is the really admirable, cheap, always ready, convenient and comfortable london hansom; while the way to see london is from the top of an omnibus, the most enjoyable, if not the most expeditious, means of conveyance. * * * * * [continued from supplement, no. , page .] riveted joints in boiler shells.[ ] [footnote : a paper read at a meeting of the franklin institute. from the journal of the institute.] by william barnet le van. [illustration: fig. .] fig. represents the spacing of rivets composed of steel plates three-eighths inch thick, averaging , pounds tensile strength on boiler fifty-four inches diameter, secured by iron rivets seven-eighths inch diameter. joints of these dimensions have been in constant use for the last fourteen years, carrying pounds per square inch. _punching rivet holes._--of all tools that take part in the construction of boilers none are more important, or have more to do, than the machine for punching rivet holes. that punching, or the forcible detrusion of a circular piece of metal to form a rivet hole, has a more or less injurious effect upon the metal plates surrounding the hole, is a fact well known and admitted by every engineer, and it has often been said that the rivet holes ought all to be drilled. but, unfortunately, at present writing, no drilling appliances have yet been placed on the market that can at all compare with punching apparatus in rapidity and cheapness of working. a first-class punching machine will make from forty to fifty holes per minute in a thick steel plate. where is the drilling machine that will approach that with a single drill? the most important matter in punching plates is the diameter of the opening in the bolster or die relatively to that of the punch. this difference exercises an important influence in respect not only of easy punching but also in its effect upon the plate punched. if we attempt to punch a perfectly cylindrical hole, the opening in the die block must be of the same diameter as the point of the punch, or, at least, a very close fit. the point of the punch ought to be slightly larger in diameter than the neck, or upper part, as shown in figs. and , so as to clear itself easily. when the hole in the bolster or die block is of a larger diameter than the punch, the piece of metal thrust out is of larger diameter on the bottom side, and it comes out with an ease proportionate to the difference between the lower and upper diameters; or, in other words, it produces a taper hole in the plate, but allows the punching to be done with less consumption of power and, it is said, with less strain on the plate. [illustration: fig. .] [illustration: fig. .] as to the difference which should exist between the diameter of the punch and the die hole, this varies a little with the thickness of the plate punched, or should do so in all carefully executed work, for it is easy to understand that the die which might give a suitable taper in a three-fourths inch plate would give too great a taper in a three-eighths inch plate. there is no fixed rule; practical experience determines this in a rough and ready way--often a very rough way, indeed, for if a machine has to punch different thicknesses of plate for the same size of rivets, the workman will seldom take the trouble to change the die with every variation of thickness. the maker of punches and dies generally allows about three sixty-fourths or . of an inch clearance. the following formula is also used by punch and die makers: clearance = d = d + . t where d = diameter of hole in die block; d = diameter of cutting edge of punch; t = thickness of plate in fractions of an inch; that is to say, the diameter of the die hole equals diameter of punch plus two-tenths the thickness of the plate to be punched. _example_.--given a plate / or . of an inch thick, the diameter of the punch being / or . of an inch, then the diameter of the die hole will be as follows: diameter of die hole = . + . x . = . inch diameter, or say / or . inch diameter. punches are generally made flat on their cutting edge, as shown in fig. . there are also punches made spiral on their cutting edge, as shown in fig. . this punch, instead of being flat, as in fig. , is of a helical form, as shown in fig. , so as to have a gradual shearing action commencing at the center and traveling round to the circumference. its form may be explained by imagining the upper cutter of a shearing machine being rolled upon itself so as to form a cylinder of which its long edge is the axis. the die being quite flat, it follows that the shearing action proceeds from the center to the circumference, just as in a shearing machine it travels from the deeper to the shallower end of the upper cutter. the latter is not recommended for use in metal of a thickness greater than the diameter of the punch, and is best adapted for thicknesses of metal two-thirds the diameter of the punch. fig. shows positions of punch and attachments in the machine. [illustration: fig. .] it is of the greatest importance that the punch should be kept sharp and the die in good order. if the punch is allowed to become dull, it will produce a fin on the edge of the rivet hole, which, if not removed, will cut into the rivet head and destroy the fillet by cutting into the head. when the punch is in good condition it will leave a sharp edge, which, if not removed, will also destroy the fillet under the head by cutting it away. punching possesses so many advantages over drilling as to render it extremely important that the operation should be reduced to a system so as to be as harmless as possible to the plate. in fact, no plate should be used in the construction of a boiler that does not improve with punching, and further on i will show by the experiments made by hoopes & townsend, of philadelphia, that good material is improved by punching; that is to say, with properly made punches and dies, by the upsetting around the punched hole, the value of the plate is increased instead of diminished, the flow of particles from the hole into the surrounding parts causing stiffening and strengthening. _drilling rivet holes._--in the foregoing i have not referred to the drilling of rivet holes in place of punching. the great objection to drilling rivet holes is the expense, from the fact that it takes more time, and when drilled of full rivet size we are met with the difficulty of getting the rivet holes to correspond, as they are when punched of full rivet diameter. when two plates are drilled in place together, the drill will produce a _burr_ between the two plates--on account of their uneven surfaces--which prevents them being brought together, so as to be water and steam tight, unless the plates are afterward separated and the burr removed, which, of course, adds greatly to the expense. the difference in strength between boiler plates punched or drilled of full rivet size may be either greater or less than the difference in strength between unperforated plates of equal areas of fracture section. when the metal plates are very soft and ductile, the operation of punching does no appreciable injury. prof. thurston says he has sometimes found it actually productive of increased strength; the flow of particles from the rivet hole into the surrounding parts causing stiffening and strengthening. with most steel and hard iron plates the effect of punching is often to produce serious weakening and a tendency to crack, which in some cases has resulted seriously. with first class steel or iron plates, punching is perfectly allowable, and the cost is twenty-five per cent. less than drilling; in fact, none but first class metal plates should be used in the construction of steam boilers. in the original punching machines the die was made much larger than the punch, and the result was a conical taper hole to receive the rivet. with the advanced state of the arts the punch and die are accurately fitted; that is to say, the ordinary clearance for a rivet of (say) three-fourths of an inch diameter, the dies have about three sixty-fourths of an inch, the punch being made of full rivet size, and the clearance allowed in the diameter of the die. take, for example, cold punched nuts. those made by messrs. hoopes & townsend, philadelphia, when taken as specimens of "commercial," as distinguished from merely experimental punching, are of considerable interest in this connection, owing to the entire absence of the conical holes above mentioned. when the holes are punched by machines properly built, with the punch accurately fitted to the die, the effect is that the metal is made to flow around the punch, and thus is made more dense and stronger. that some such action takes place seems probable, from the appearance of the holes in the hoopes & townsend nuts, which are straight and almost as smooth as though they were drilled. therefore i repeat that iron or steel that is not improved by proper punching machinery is not of fit quality to enter into the construction of steam boilers. strength of punched and drilled iron bars. hoopes & townsend. ----------------+------------------+----------------+----------------+ thickness of bar|thickness outside | punched bars | drilled bars | in inches. |of hole in inches.|broke in pounds.|broke in pounds.| ----------------+------------------+----------------+----------------+ / or . | / or . | , | , | / or . | / or . | , | , | / or . | / or . | , | , | / or . | / or . | , | , | / or . | / or . | , | , | / or . | / or . | , | , | / or . | / or . | , | , | / or . | / or . | , | , | ---------------------------------------------------------------------+ it will be seen from the above that the punched bars had the greatest strength, indicating that punching had the effect of strengthening instead of weakening the metal. these experiments have given results just the reverse of similar experiments made on boiler plates; but the material, such as above experimented upon, is what should be placed in boilers, tough and ductile, and the manner of, and care taken in, punching contribute to these results. it is usual to have the rivet holes one-sixteenth of an inch in diameter larger than the rivets, in order to allow for their expansion when hot; it is evident, however, that the difference between the diameters of the rivet hole and of the rivet should vary with the size of the rivet. the hole in the die is made larger than the punch; for ordinary work the proportion of their respective diameters varies from : . to : . as i have before stated, the best plate joint is that in which the strength of the plate and the resistance of the rivet to shearing are equal to each other. in boilers as commercially made and sold the difference in quality of the plates and rivets, together with the great uncertainty as to the exact effect of punching the plates, have, so far, prevented anything like the determination either by calculation or experiment of what might be accepted as the best proportions of riveted joints. in regard to steel plates for boilers mr. f.w. webb, of crewe, england, chief engineer of the london and northwestern railway, has made over , tests of steel plates, but had only two plates fail in actual work; these failures he thought were attributable solely to the want of care on the part of the men who worked the plates up. all their rivet holes for boilers were punched in a jacquard machine, the plates then annealed, and afterward bent in rolls; they only used the reamer slightly when they had three thicknesses of plate to deal with, as in butt joints with inside and outside covering strips. these works turn out two locomotive boilers every three days. the baldwin locomotive works, which turn out on an average three locomotives per day, punch all their rivet holes one sixteenth inch less in diameter and ream them to driven rivet size when in place. they also use rivets with a fillet formed under head made in solid dies. _rivets._--rivets of steel or iron should be made in solid dies. rivets made in open dies are liable to have a fin on the shank, which prevents a close fit into the holes of the plates. the use of solid dies in forming the rivet insures a round shank, and an accurate fit in a round hole. in addition, there is secured by the use of solid dies, a strong, clean fillet under the head, the point where strength is most needed. commencing with a countersunk head as the strongest form of head, the greater the fillet permissible under the head of a rivet, or bolt, the greater the strength and the decrease in liability to fracture, as a fillet is the life of the rivet. if rivets are made of iron, the material should be strong, tough, and ductile, of a tensile strength not exceeding , pounds per square inch, and giving an elongation in _eight inches_ of not less than twenty-five per cent. the rivet iron should be as ductile as the best boiler plate when cold. iron rivets should be annealed and the iron in the bar should be sufficiently ductile to be bent cold to a right angle without fracture. when heated it should be capable of being flattened out to one-third its diameter without crack or flaw. [illustration: fig. . solid die rivet.] [illustration: fig. . open die rivet.] if rivets are made of steel they must be low in carbon, otherwise they will harden by chilling when the hot rivets are placed in the cold plates. therefore, the steel must be particularly a low grade or mild steel. the material should show a tensile strength not greater than , pounds per square inch and an elongation in _eight inches_ of thirty per cent. the united states government requirements are that steel rivets shall flatten out cold under the hammer to the thickness of one-half their diameter without showing cracks or flaws; shall flatten out hot to one-third their diameter, and be capable of being bent cold in the form of a hook with parallel sides without cracks or flaws. these requirements were thought at first to be severe, but the makers of steel now find no practical difficulty in meeting these specifications. the forming of the head of rivets, whether of steel or iron, and whether the heads are conical or semi-spherical, should not be changed by the process of riveting. the form of the head is intended to be permanent, and this permanent form can only be retained by the use of a "hold fast," which conforms to the shape of the head. in the use of the flat hold fast (in general use in a majority of boiler shops) the form of the head is changed, and if the rivet, by inadequate heating, requires severe hammering, there is danger that the head of the rivet may be "punched" off. by the use of a hold fast made to the shape of the rivet head, this danger is avoided and the original form of the head is retained. this feature of the use of proper rivet tools in boiler shops has not received the attention it deserves. practical use of the above named hold fast would soon convince the consumers of rivets of its value and efficiency. the practice of driving rivets into a punched rivet hole from which the fin or cold drag, caused by the movement of the punch, has not been removed by reaming with a countersunk reamer, or better still a countersunk set, should be condemned, as by driving the hot rivet head down against the fin around the hole in the cold plate caused by the action of punching the countersunk fillet is not only destroyed, but it is liable to be driven into the head of the rivet, partially cutting the head from the shank. if the rivet is driven into a hole that has been punched with a sharp punch and sharp die, the result is that the fillet is cut off under the head, and the riveted end is also cut, and does not give the clinch or hold desired. that is to say, rivet holes in plates to be riveted should have the burr or sharp edge taken off, either by countersinking, by reamer, or set. _heating of rivets._--iron rivets are generally heated in an ordinary blacksmith's or rivet fire having a forced blast; they are inserted with the points down into the fire, so that the heads are kept practically cool. steel rivets should be heated in the hearth of a reverberatory furnace so arranged that the flame shall play over the top of the rivets, and should be heated uniformly throughout the entire length of the rivet to a cherry red. particular attention must be given to the thickness of the fire in which they are heated. steel, of whatever kind, should never be heated in a thin fire, especially in one having a forced blast, such as an ordinary blacksmith's or iron rivet furnace fire. the reason for this is that more air passes through the fire than is needed for combustion, and in consequence there is a considerable quantity of free oxygen in the fire which will oxidize the steel, or in other words, burn it. if free oxygen is excluded steel cannot burn; if the temperature is high enough it can be melted and will run down through the fire, but burning is impossible in a thick fire with a moderate draught. this is an important matter in using steel rivets and should not be overlooked; the same principle applies to the heating of steel plates for flanging. _riveting._--there are four descriptions of riveting, namely: ( ) hammered or hand riveting. ( ) snapped or set. ( ) countersunk. ( ) machine. for good, sound work, machine riveting is the best. snapped riveting is next in quality to machine riveting. countersunk riveting is generally tighter than snapped, because countersinking the hole is really facing it; and the countersunk rivet is, in point of fact, made on a face joint. but countersinking the hole also weakens the plate, inasmuch as it takes away a portion of the metal, and should only be resorted to where necessary, such as around the front of furnaces, steam chests or an odd hole here and there to clear a flange, or something of that sort. hammered riveting is much more expensive than machine or snapped riveting, and has a tendency to crystallize the iron in the rivets, causing brittleness. in the present state of the arts all the best machine riveters do their work by pressure, and not by impact or blow. the best machines are those of the hydraulic riveting system, which combines all of the advantages and avoids all the difficulties which have characterized previous machine systems; that is to say, the machine compresses without a blow, and with a uniform pressure at will; each rivet is driven with a single progressive movement, controlled at will. the pressure upon the rivet after it is driven is maintained, or the die is retracted at will. [illustration: fig. .] hydraulic riveting has demonstrated not only that the work could be as well done without a blow, but that it could be _better done without a blow_, and that the riveted material was stronger when so secured than when subjected to the more severe treatment under impact. what is manifestly required in perfect riveting is that the metal of the rivet while hot and plastic shall be made to flow into all the irregularities of the rivet holes in the boiler sheets; that the surplus metal be formed into heads as large as need be, and that the pressure used to produce these results should not be in excess of what the metal forming the boiler shall be capable of resisting. it is well known that metals, when subjected, either cold or hot, to sufficient pressure, will obey almost exactly the same laws as fluids under similar conditions, and will flow into and fill all the crevices of the chamber or cavity in which they are contained. if, therefore, a hot rivet is inserted into the holes made in a boiler to receive it, and is then subjected to a sufficient pressure, it will fill every irregularity of the holes, and thus fulfill one of the conditions of perfect riveting. this result it is impossible to accomplish with perfection or certainty by ordinary hand riveting, in doing which the intermittent blows of an ordinary hammer are used to force the metal into the holes. with a hydraulic riveting machine, however, an absolutely uniform and continuous pressure can be imparted to each rivet, so as to force the hot metal of the rivet into all the irregularities of the holes in the same way as a hydraulic ram will cause water to fill any cavity, however irregular. [illustration: fig. .] in order to illustrate the relative advantages of machine over hand riveting, two plates were riveted together, the holes of which were purposely made so as not to match perfectly. these plates were then planed through the center of the rivets, so as to expose a section of both the plates and rivets. from this an impression was taken with printer's ink on paper and then transferred to a wooden block, from which figs. and were made. the machine-driven rivet is marked _a_, and _b_ represents the hammered rivet. it will be observed that the machine rivet fills the hole completely, while the hand rivet is very imperfect. this experiment was tried several times, with similar results each time. the hand rivet, it will be observed, filled up the hole very well immediately under the head formed by the hammer; but sufficient pressure could not be given to the metal--or at least it could not be transferred far enough--to affect the metal at some distance from the driven head. so great is this difficulty that in hand riveting much shorter rivets must be used, because it is impossible to work effectively so large a mass of metal with hammers as with a machine. the heads of the machine rivets are, therefore, larger and stronger, and will hold the plates together more firmly than the smaller hammered heads. to drive rivets by hand, two strikers and one helper are needed in the gang, besides the boy who heats and passes the rivets; to drive each five-eighths inch rivet, an average of blows of the hammer is needed, and the work is but imperfectly done. with a machine, two men handle the boiler, and one man works the machine; thus, with the same number of men as is required in riveting by hand, five rivets are driven each minute. the superior quality of the work done by the machine would alone make its use advantageous; but to this is added greatly increased amount of work done. the difference in favor of the riveting machine over hand riveting is at least _ten_ to _one_. in a large establishment a record of the number of rivets driven by the hand-driving gang, also by the gang at the steam-riveting machine for a long period of time, in both cases making no allowances of any kind of delays, the rivets driven per month by each was--for the hand driven rivets at the rate of twelve rivets per hour, and for the machine driven rivets, per hour. in the case of the hand driven rivets the boiler remains stationary and the men move about it, while the machine driven rivets require the whole boiler to be hoisted and moved about at the riveting machine to bring each hole to the position required for the dies. notwithstanding the trouble involved in handling and moving the boiler, it shows that it is possible to do ten times as much work, and with less skilled labor, by the employment of the riveting machine. _calking._--one great source of danger in boiler making is excessive joint calking--both inside and out--where a sharp nosed tool is employed, and for the reason that it must be used so close to the inner edge of plate as to indent, and in many cases actually cut through the skin of the lower plate. this style of calking puts a positive strain upon the rivets, commencing distortion and putting excessive stress upon rivets--already in high tension before the boiler is put in actual use. it is, i hope, rapidly becoming a thing of the past. with a proper proportion of diameter and pitch of rivet, all that is required is the use of a light "fuller tool" or the round-nosed tool used in what is known to the trade as the "connery system." there is but little need of calking if means are taken to secure a clean metal-to-metal face at the joint surfaces. when the plates are put together in ordinary course of manufacture, a portion of the mill scale is left on, and this is reduced to powder or shaken loose in the course of riveting and left between the plates, thus offering a tempting opening for the steam to work through, and is really cause of the heavy calking that puts so unnecessary a pressure on both plate and rivet. a clean metallic joint can be secured by passing over the two surfaces a sponge wet with a weak solution of sal-ammoniac and hot water, an operation certainly cheap enough both as to materials and labor required. [illustration: fig. ] the above cut, fig. , gives an illustration of calking done by sharp-nosed and round nosed tools, respectively. it will be seen by fig. that the effect of a round-nosed tool is to divide the plate calked, and as the part divided is well driven toward the rivets, a bearing is formed at _a_, from one-half to three-fourths of an inch, which increases the strength of joint, and will in no way cut or injure the surface of the under plate. a perfect joint is thus secured. [illustration: fig. .] * * * * * the new british battle ship empress of india. the launching of this first-class battle ship was successfully carried out at pembroke dockyard on may . she is the second of a class of eight battle ships built and building under the naval defense act of , which were specially designed to take part in general fleet actions in european waters. the leading dimensions are: length, between perpendiculars, ft.; breadth, extreme, ft.; mean draught of water, ft. in.; and displacement at this draught, , tons, which surpasses that of any other ship in the navies of the world. previous to the launching of the royal sovereign--a sister vessel--which took place at portsmouth in february last, the largest war ships in the british navy were the nile and trafalgar, each of , tons, and these were largely exceeded in displacement by the italia, of , tons, and the lepanto, of , tons, belonging to the italian navy. the empress of india is built throughout of mild steel, the stem and stern post, together with the shaft brackets, being of cast steel. steel faced armor, having a maximum thickness of in., extends along the sides for ft. amidships, the lower edge of the belt being ft. in. below the normal water line. the belt is terminated at the fore and after ends by transverse armored bulkheads, over which is built a in. protective steel deck extending to the ends of the vessel and terminating forward at the point of the ram. above the belt the broadside is protected by in. armor, the central battery being inclosed by screen bulkheads of the same thickness. the barbettes, which are formed of armor in. thick, rise from the protective deck at the fore and after ends of the main belt. the principal armor throughout is backed by teak, varying in thickness from in. to in., behind which is an inner skin of steel in. thick. the engines are being constructed by messrs. humphreys, tennant & co, london, and are of the vertical triple expansion type, capable of developing a maximum horse power of , with forced draught and , horse power under natural draught, the estimated speeds being and ½ knots respectively at the normal displacement. the regular coal supply is tons, which will enable the ship to cover a distance of , knots at a reduced speed of ten knots and about , knots at her maximum speed. the main armament of the empress will consist of four ton breechloading guns mounted in pairs _en barbette_. the secondary armament includes ten in. pounder quick firing guns, four being mounted on the main deck and six in the sponsons on the upper deck, sixteen pounder and nine pounder quick-firing guns, in addition to a large number of machine guns. the largest guns at present mounted in any british warship are the ton guns mounted in the benbow class, and the difference between these weapons and those to be carried by the empress of india is very marked. the projectile fired from either of the benbow's heavy gun weighs , lb., and is capable of penetrating in. of unbacked wrought iron at a distance of , yards. the projectile fired from the ton guns of the empress of india will have much less penetrating power, being only equal to in. of wrought iron with a full charge of lb. of prismatic brown powder, the missile weighing , lb. or about one-half less than the weight of the shot used with the ton gun. it will thus be seen that the ordnance of the benbow can penetrate armor that would defy the attack of the guns of the empress. it should be said, however, that the heavy artillery of the latter vessel is capable of penetrating any armor at present afloat, and is carried at a much greater height above the designed load water line than in any existing battle ship, either in the british or foreign navies. the armor being of less weight, too, enables the new ship, and others of her class, to carry an auxiliary armament of unprecedented weight and power. the empress will be lighted throughout by electricity, the installation comprising some lights, and will be provided with four , candle power search lights, each of which will be worked by a separate dynamo. the ship has been built from the designs of mr. w.h. white, c.b., director of naval construction, and will be fitted out for the use of an admiral, and when commissioned her complement of officers and men will number .--_industries._ * * * * * the "iron gates" of the danube. the work of blowing up the masses of rock which form the dangerous rapids known as the iron gates, on the danube, was inaugurated on september , , when the greben rock was partially blown up by a blast of sixty kilogrammes of dynamite, in the presence of count szapary, the hungarian premier; m. baross, hungarian minister of commerce; count bacquehem, austrian minister of commerce; m. gruitch, the servian premier; m. jossimovich, servian minister of public works; m. de szogyenyi, chief secretary in the austro-hungarian ministry of foreign affairs; and other hungarian and servian authorities. large numbers of the inhabitants had collected on both banks of the danube to witness the ceremony, and the first explosion was greeted with enthusiastic cheers. the history of this great scheme was told at the time the hungarian parliament passed the bill on the subject two years ago. it is known that the roman emperor trajan, seventeen centuries ago, commenced works, of which traces are still to be seen, for the construction of a navigable canal to avoid the iron gates. for the remedy of the obstruction in the danube, much discussed of late years, there were two rival systems--the french, which proposed to make locks, and the english and american, which was practically the same as that of trajan, namely, blasting the minor rocks and cutting canals and erecting dams where the rocks were too crowded. the latter plan was in principle adopted, and the details were worked out, in , by the hungarian engineer willandt. the longest canal will be that on the servian bank, with a length of over two kilometers and a width of eighty meters. it will be left for a later period to make the canal wider and deeper, as was done with the suez canal. for the present it is considered sufficient that moderate sized steamers shall be able to pass through without hindrance, and thus facilitate the exchange of goods between the west of europe and the east. the first portion of the rocks to be removed, and of the channels to be cut, runs through hungarian territory; the second portion is in servia. the new waterway will, it is anticipated, be finished by the end of , and then, for the first time in history, black sea steamers will be seen at the quays of pesth and vienna, having, of course, previously touched at belgrade. the benefit to servian trade will then be quite on a par with that of austria-hungary. even germany will derive benefit from this extension of trade to the east. these, however, are by no means the only countries which will be benefited by the opening of the great river to commerce. turkey, southern russia, roumania, and bulgaria, not to speak of the states of the west of europe, will reap advantage from this new departure. england, as the chief carrier of the world, is sure to feel the beneficial effects of the danube being at length navigable from its mouth right up to the very center of europe. the removal of the iron gates has always been considered a matter of european importance. the treaty of paris stipulated for freedom of navigation on the danube. the london treaty of again authorized the levying of tolls to defray the cost of the danube regulation; and article of the treaty of berlin intrusted austria-hungary with the task of carrying out the work. by these international compacts the european character of the great undertaking is sufficiently attested. [illustration: the "iron gates" of the danube] the work of blasting the rocks will be undertaken by contractors in the employ of the hungarian government, as the official invitation for tenders brought no offers from any quarter. the construction of the dams, however, and the cutting of several channels to compass the most difficult rocks and rapids, will be carried out by an association of pesth and other firms. the cost, estimated altogether at nine million florins, will be borne by the hungarian exchequer, to which will fall the tolls to be levied on all vessels passing through the gates until the original outlay is repaid. very few persons know, says the _american architect_, what an enormous work has been undertaken at the iron gates of the danube, where operations are rapidly progressing, mainly in accordance with a plan devised many years ago by our distinguished countryman, mr. mcalpine. the total length of that part of the river to be regulated is about two hundred and fifty miles, so that the enterprise ranks with the cutting of the panama and suez canals as one of the greatest engineering feats ever attempted. work has been begun simultaneously at three points: at greben, where there are reefs to be taken care of; at the cataract, near jucz, and at the iron gate proper, below orsova. at greben, where the stream is shallow, but swift, a channel two hundred feet wide is to be blasted out of the rock, and below it a stone embankment wall is to be built more than four miles long. from a reef which projects into the river a piece is to be blasted away, measuring five hundred feet in length, and about nine feet in depth. the difficulties of working in this part of the river are very great. not only is the current extremely rapid, but in certain places ridges of rock barely covered at low water alternate with pools a hundred and forty feet deep, which give rise, in the rapid current, to frightful whirlpools and eddies. these deep pools are to be filled at the same time that the reefs are cut away, and it is estimated that nearly three million cubic feet of loose stonework will be needed for this purpose alone. in addition to the excavation, artificial banks and breakwaters, for modifying the course of the stream, are to be built; so that it is estimated that the masonry to be executed in this section will amount to about five and one-half million cubic feet. in the cataract section, at jucz, a channel two hundred feet wide, and more than half a mile long, is to be blasted out of the rock, and a breakwater built, to moderate the suddenness of the fall. this breakwater is to be about two miles long, and ten feet thick at the top, increasing in thickness toward the bottom. the rock in which the channel must be cut at this point is partly serpentine greenstone, partly chrome iron ore, and is intensely hard. in the section of the iron gate, the work to be done consists in "canalizing" the river for a distance of a mile and a half, by building a wall on each side, and excavating the bed of the river between. the channel between the walls will be two hundred and fifty feet wide. it is estimated that nearly three million cubic feet of rock will have to be excavated here, all of which will be used to fill in behind the embankment walls. of course, the greater part of the rock will be removed by means of blasting with high explosives, but some of it is to be attacked with a novel instrument, which was first tried, on a small scale, on the panama canal, and is to be used for serious work here. this instrument, as it is to be employed on the danube, consists of an enormous steel drill, thirty-three feet long, and weighing ten tons. by means of a machine like a pile driver, this monstrous tool is raised to a height of about fifty feet, and allowed to drop, point first. so heavy a mass of metal, falling from a considerable height, meets with comparatively little resistance from the water, and the point shatters and grinds up the rock on which it strikes. fifty or sixty blows per minute can be struck with a tool of this kind, and ten thousand blows in all can be inflicted before the tool is so worn as to be past service. several of these drills will be at work at the same time, and to remove the fragments of rock which they break off, a huge dredge of three hundred and fifty horse power is to be employed. for excavating by means of explosives, arrangements have been made for drilling the holes for the cartridges with the greatest possible rapidity, as on this depends the celerity with which the work can be pushed forward. much of the work will be done by means of diamond drills, which are mounted on boats. five of these boats have been provided, each with seven diamond drills, arranged so as to work perfectly in twenty feet of water. other boats are fitted with pneumatic drills, which are operated by means of air, compressed to a tension of seven hundred and fifty pounds to the square inch. the pressure of the compressed air is transmitted by means of water to the drills, which act by percussion, and work very rapidly. these drills are curiously automatic in their operation. after boring the holes to the allotted depth, the machine automatically sets in each a tube, washes out the dust, inserts a dynamite cartridge, withdraws the tube, and connects the wire of the electric fuse in the cartridge with the battery wire in the boat. the cartridges are charged with a pound of dynamite to each. in hard rock only one charge is fired at a time, but in softer material four are fired at once. if the water over the work is deep, the boat is not moved from its position, but in shallow water it is towed a few yards away from the spot where the explosion is to take place. the drill holes are about six feet deep, and are spaced at the rate of about one to every three square feet, something, of course, depending upon the character of the rock. the whole work is now under contract, the mechanical engineering firm of luther, of brunswick, having undertaken to complete it in five years, for a payment of less than four million dollars. * * * * * the new german ship canal. the gates which admit the water into the new canal which is to connect the baltic with the north sea have been recently opened by the emperor william. this canal is being constructed by the german government principally for the purpose of strengthening the naval resources of germany, by giving safer and more direct communication for the ships of the navy to the north german ports. the depth of water will be sufficient for the largest ships of the german navy. the canal will also prove of very great advantage to the numerous timber and other vessels trading between st. petersburg, stockholm, dantzic, riga, and all the north german ports in the baltic and this country. the passage by the kattegat and skager rack is exceedingly intricate and very dangerous, the yearly loss of shipping being estimated at half a million of money. in addition to the avoidance of this dangerous course, the saving in distance will be very considerable. thus, for vessels trading to the thames the saving will be miles, for those going to lynn or boston , to hull , to newcastle or leith . this means a saving of three days for a sailing vessel going to boston docks, the port lying in the most direct line from the timber ports of the baltic to all the center of england. the direction of the canal is shown by the thick line in the accompanying sketch map of the north sea and baltic. considering that between , and , ships now pass through the sound annually, the advantage to the baltic trade is very apparent. [illustration: the new german ship canal.] the new canal starts at holtenau, on the north side of the kiel bay, and joins the elbe fifteen miles above the mouth. from kiel bay to rendsborg, at the junction with the eider, the new canal follows the schleswig and holstein canal, which was made about one hundred years ago, and is adapted for boats drawing about eight feet; thence it follows the course of the eider to near willenbergen, when it leaves that river and turns southward to join the elbe at brunsbuttel, about forty miles below hamburg. the canal is miles long, ft. wide at the surface, and ft. at the bottom, the depth of water being ft. the surface of the water in the two seas being level, no locks are required; sluices or floodgates only being provided where it enters the eider and at its termination. the country being generally level there are no engineering difficulties to contend with, except a boggy portion near the elbe; the ground to be removed is chiefly sandy loam. four railways cross the canal and two main roads, and these will be carried across on swing bridges. the cost is estimated at £ , , . about six thousand men are employed on the works, principally italians and swiss.--_the engineer._ * * * * * the kioto-fu canal, in japan. japan is already traversed by a system of railways, and its population is entering more and more into the footsteps of western civilization. this movement, a consequence of the revolution of , is extending to the public works of every kind, for while the first railway lines were being continued, there was in the course of excavation (among other canals) a navigable canal designed to connect lake biwa and the bay of osaka, upon which is situated kioto, the ancient capital of japan. the work, which was begun in , was finished last year, and one of our readers has been kind enough to send us, along with some photographs which we herewith reproduce, a description written by mr. s. tanabe, engineer in chief of the work. the object of the kioto-fu canal is not only to provide a navigable watercourse, putting the interior of the country in connection with the sea, but also to furnish waterfalls for supplying the water works of the city of kioto with the water necessary for the irrigation of the rice plantations, and that employed for city distribution. it starts from the southwest extremity of lake biwa, the largest lake in japan, and the area of which is square kilometers. this lake, which is situated at meters above the level of the sea, is kilometers from the bay of osaka. as this bay is already in communication with kioto by a canal, the kioto-fu forms a junction with the latter after a stretch of kilometers and a difference of level of meters between its extremities. [illustration: fig. .--extremity of lake biwa and beginning of the canal.] the lake terminates in a marshy plain (fig. ), in which the first excavation was made. this is protected by longitudinal dikes which lead back the water to it in case of freshets. at the end of this cutting, which is meters in length, begins the canal properly so called, with a width of . meters, at the surface, and a depth of . meters, for a length of meters. it then reaches the first tunnel for crossing the nagara-yama chain. this tunnel is , meters in length, . in width and . in height. the water reaches a depth of . meters upon the floor. it was pierced through very varied materials, such as clay, schists, sandstone and porphyry, and is lined throughout with brick masonry. the construction was effected by means of a working shaft meters in depth, sunk in the axis of the work, at a third of its length from the west side. at the upper extremity are established sluices that permit of securing to the canal a constant discharge of . cubic meters per second. fig. represents the head of this work. [illustration: fig. .--head of the principal tunnel.] starting from the tunnel, the canal extends in the open air for a length of , meters. to reach the basin of kioto, it traverses the hino-oko-yama chain of hills, through two tunnels of the same section and construction as the one just mentioned, and of the respective lengths of and meters. traction in the tunnels is to be effected by means of an immersed chain. on leaving tunnel no. , at about , meters from its origin, the canal divides into two branches. the first of these, which is designed to serve as a navigable way, has a slope . per meter for a length of meters. it is a true inclined plane, which the boats pass over by means of a cradle carried by trucks and drawn by a cable actuated by the fall furnished by the other branch. at the foot of the inclined plane, the canal widens out to meters at the surface, with a depth of . meter, and, through a sluice, joins the osaka bay canal, after a stretch of kilometers. [illustration: fig. .--aqueduct over the valley of the tombs of the emperors.] the second branch traverses a small tunnel, crosses the valley of the emperors' tombs upon an aqueduct of arches (fig. ), and reaches kogawa, a faubourg north of kioto, after a stretch of kilometers. its slope is greater than that of the main canal, from which it derives but . cubic meter. the cubic meters remaining may be employed for the production of motive power under a fall of meters. it is proposed to utilize a portion of it, at the point of bifurcation and at the top of the inclined plane, in a hydraulic installation that will drive electric machines. the total cost of the work was one million dollars, a third of which was furnished by the imperial treasury, a quarter by the central government, and the rest by various taxes.--_la nature._ * * * * * how to find the crack.--most mechanics know that by drilling a hole at the inner end of a crack in cast metal its extension can be prevented. but to find out the exact point where the crack ends, the _revue industrielle_ recommends moistening the cracked surface with petroleum, then, after wiping it, to immediately rub it with chalk. the oil that has penetrated into the crack will, by exudation, indicate the exact course and end of the crack. * * * * * fast and fugitive dyes.[ ] [footnote : a paper recently read before the society of arts, london.] by prof. j.j. hummel. as it is with many other arts, the origin of dyeing is shrouded in the obscurity of the past; but no doubt it was with the desire to attract his fellow that man first began to imitate the variety of color he saw around him in nature, and colored his body or his dress. probably the first method of ornamenting textile fabrics was to stain them with the juices of fruits, or the flowers, leaves, stems, and roots of plants bruised with water, and we may reasonably assume that the primitive colors thus obtained would lack durability. by and by, however, it was found possible to render some of the dyes more permanent, probably in the first instance by the application of certain kinds of earth or mud, as we know to be practiced by the maori dyers of to-day, and in this way, as it appears to me, the early dyers learnt the efficacy of what we now call "mordants," which i may briefly describe as fixing agents for coloring matters. at a very remote period therefore, i imagine, the subject of fast and fugitive dyes engaged the attention of textile colorists. our european knowledge of dyeing seems to have come to us from the east, and although at first indigenous dyestuffs were largely employed, with the discovery of new countries many of these fell slowly and gradually into disuse, giving way to the newly imported dyestuffs of other lands, which possessed some advantage, being either richer in coloring matter, yielding brighter or faster colors, or being capable of more easy application. thus kermes gave way to cochineal, woad to indigo, and so on. down to about the year , natural dyestuffs alone, with but one or two exceptions, were employed by dyers; but in that year a present distinguished member of this society, dr. perkin, astonished the scientific and industrial world by his epoch-making discovery of the coal tar color mauve. from that time down to the present, the textile colorist has had placed before him an ever increasing number of coloring matters derived from the same source. specially worthy of notice are the discoveries of artificial alizarin, in , by graebe and liebermann, and of indigotin, in , by adolf baeyer, both coloring matters being identical with the respective dyes obtained from plants. in view of the vast array of coal tar colors now at our disposal, and their almost universal application in the decoration of all manner of textile fabrics, threatening even the continued use of well known dyestuffs of vegetable origin, it becomes of the greatest importance to examine most thoroughly, and to compare the stability of both old and new coloring matters. the first point in discussing this question of fast and fugitive dyes is to define the meaning of these terms "fast" and "fugitive." unfortunately, as frequently employed, they have no very definite signification. the great variety of textile fabrics to which coloring matters are applied, the different stages of manufacture at which the coloring matter is applied, and the many uses to which the fabrics are ultimately put, all these are elements which cause dyed colors to be exposed to the most varied influences. the term a "fast color," then, may convey a different meaning to different individuals. to one it implies that the color will not fade when exposed to light and atmospheric conditions; to another that it is not impoverished by washing with soap and water; to a third it may indicate that the color will withstand the action of certain manufacturing operations, such as scouring, milling, stoving, etc.; while a fourth person might be so exacting as to demand that a fast color should resist all the varied influences i have named. it is well to state at once that no dyed color is absolutely fast, even to a single influence, and it certainly cannot pass unscathed through all the operations to which it may be necessary to submit individual colors applied to this or that material. many colors are fast to washing or milling, and yet very fugitive to light; others are fast to light, but fugitive toward milling; while others again are fast to both influences. in short, each color has its own special, characteristic properties, so that colors may be classified with respect to each particular influence, and may occupy a very different rank in the different arrangements. it is, however, by no means necessary to demand absolute fastness from any color. a color may "bleed" in milling, and therefore be very unsuitable for tweeds, and yet be most excellent for curtains and hangings, because of its fastness to light. so, too, a dye capable of yielding rich or delicate tints, but only moderately fast to light, may still be perfectly well adapted for the silks and satins of the ball room, or even the rapidly changing fashion, although it would be quite inadmissible for the pennon at the masthead. the colors of carpets, curtains, and tapestry should certainly be fast to light, but no one expects them to undergo the fatigue of the weekly washtub; and just as little as we look for the exposure of flannels and hosiery, day by day and week by week, to the glare of sunlight, much as we desire that the colors shall not run in washing. for all practical purposes, then, it seems reasonable to define a "fast color" as one which will not be materially affected by those influences to which, in the natural course of things, it will be submitted. hence, in speaking of a fast color, it becomes necessary to refer specially to the particular influences which it resists before the term acquires a definite meaning. to be precise, one should say that a color is "fast to light," or "fast to washing," or "fast to light and washing," and so on. further, it is necessary, as we shall see afterward, to give always the name of the fiber to which the color is applied. all that i have said with respect to the term "fast" may be applied with equal propriety to the term "fugitive." this, too, has no very definite meaning until a qualifying statement, such as i have referred to, gives it precision. the most important question to be considered is the action of light on dyed colors. that light can effect radical changes in many substances was known to the ancients. its destructive action on artists' pigments, e.g., the blackening of vermilion, was recorded , years ago by vitruvius. since that time it has been well established, by numerous observations and experiments, that light possesses, in a high degree, the power of exerting chemical action, i.e., causing the combination or decomposition of a large number of substances. the union of chlorine with hydrogen gas, the blackening of silver salts, the reduction of bichromate of potash and of certain ferric salts in contact with organic substances, are all familiar instances of the action of light. in illustration of this, i show here some calico prints produced by first preparing the calico with a solution of potassium bichromate, then exposing the dried calico under a photographic negative, and, after washing, dyeing with alizarin or some similar coloring matter. during the exposure under the negative, the light has reduced and fixed the chromium salt upon certain parts of the fiber as insoluble chromate of chromium (cr_{ }o_{ }cro_{ }) in the more protected portions, the bichromate remains unchanged, and is subsequently removed by washing. during the dyeing process, the coloring matter combines with the chromium fixed on the fiber, and thus develops the colored photograph. the prints in prussian blue are produced in a similar manner, the sensitive salt with which the calico is prepared being ammonium ferricitrate, and the developer potassium ferricyanide. investigation has shown that the most chemically active rays are those situated at the blue end of the solar spectrum; and although all the rays absorbed by a sensitive colored body affect its change, it is doubtless the blue rays which are the chief cause of the fading of colors. experiments are on record, indeed, which prove this. depierre and clouet ( - ) exposed a series of colors, printed and dyed on calico, to light which had passed through glasses stained red, orange, yellow, green, blue, and violet, corresponding to definite parts of the spectrum. they found that the blue light possessed the greatest fading power, red light the least. more recently ( - ) abney and russell exposed water colors under red, green, and blue glass, and came to the same conclusion. but the chemical energy of the sun's rays is not the sole cause of the fading of colors. there are certain contributory causes as important as the light itself. about fifty years ago, chevreul showed what these accessory causes are, by exposing to light a number of dyed colors under varied conditions, e.g., in a vacuum, in dry and moist hydrogen, dry and moist air, water vapor, and the ordinary atmosphere. he found that such fugitive colors as orchil, safflower, and indigo-carmine fade very rapidly in moist air, less rapidly in dry air, and that they experience little or no change in hydrogen or in a vacuum. the general conclusion arrived at was, that light, when acting alone, i.e., without the aid of air and moisture, exercises a very feeble influence. further, it was determined that the air and moisture, without aid of light, have also comparatively little effect on dyed colors. abney and russell, in their experiments with water colors, obtained similar results. these conclusions are exactly in accordance with our common knowledge of the old fashioned method of bleaching cotton and linen, in which the wetted fabric is exposed to light on the grass, and frequently sprinkled with water. if the material becomes dry through the absence of dew or rain, or the want of sprinkling, little or no bleaching takes place. the one color which chevreul found to behave abnormally was prussian blue. this faded even in a vacuum; but, strange to say, on keeping the faded color in the dark, and exposed to air, the color was restored. it was shown that, during the exposure to light, the color lost cyanogen, or hydrocyanic acid, while in the dark and exposed to the air, oxygen was absorbed. chevreul concluded, therefore, that the fading of prussian blue was due to a process of reduction. the prevailing opinion, however, is that the fading of colors is a process of oxidation, caused by the ozone, or hydrogen peroxide, which is probably formed in small quantity during the evaporation of the moisture present, and both these substances are powerful bleaching agents. it would be extremely convenient to have some rapid method of testing colors for fastness to light, and i believe it is the custom with some to apply certain chemical tests with this object in view. the results of my own experiments in this direction lead me to the conclusion that at present we have no sufficient substitute for sunlight for this purpose, since i have not found any oxidizing or reducing substance which affects dyed colors in all respects like the natural color-fading agencies; further, i am inclined to the opinion that the action of light varies somewhat with the different coloring matters, according to their chemical constitution and the fiber upon which they are applied. with respect to this last point, chevreul actually found that colors are faster to light on some fibers than on others, and this fact, which is generally known to practical men, is abundantly shown in the diagrams on the wall. as a rule we may say that colors are most fugitive on cotton and most permanent on wool, those on silk holding an intermediate position. still there are many exceptions to this order, especially as between silk and wool. since the time of chevreul, the action of light on dyed colors has not been seriously and exhaustively studied. from time to time, series of patterns dyed with our modern colors have been exposed to light, e.g., by depierre and clouet, joffre, muller, kallab, schmidt, and others; but the published results must at best be considered as more or less fragmentary. under the auspices of the british association, and a committee appointed at its last meeting in leeds, i hope to have the pleasure during the next few years of studying this interesting subject. to-night i propose to give you some of the prominent results already obtained in past years, in the dyeing department of the yorkshire college, where it has been our custom to expose to light and other influences the patterns dyed by our students. further, i wish to give you an ocular demonstration of the action of light or dyed colors, by means of these silk, wool, and cotton patterns, portions of which have been exposed for days and nights on the sea coast near bombay, during the month of february of this year. i may remark that this test has been a very trying one, for i estimate that it is equal to more than a year's exposure in this country. during the whole period there was cloudless sunshine, without any rain, and each evening heavy dew. i have pleasure in acknowledging the services of mr. w. reid, a former student, who superintended the exposure of the patterns, and from time to time took notes of the rate at which individual patterns faded. these diagrams contain, perhaps, the most complete series of both old and new dyes, on the three fibers, which have been simultaneously exposed to sunlight, and they form an instructive object lesson. let me first direct your attention to the diagram containing the _natural coloring matters_--those dyestuffs which were in use previous to . broadly speaking, they are of two kinds; those which dye textile materials "direct," and those which give no useful color without the aid of certain metallic salts, called "mordants." now, among the natural coloring matters, these "mordant dyes," as they may be conveniently termed, are much more numerous than the "direct dyes;" but be it observed, we have fast and fugitive colors in both classes. referring first to the wool patterns and to the "direct dyes," we find that the only really fast colors are prussian blue and vat indigo blue. turmeric, orchil, catechu, and indigo carmine are all extremely fugitive. as to the "mordant dyes," some yield fast colors with all the usual mordants, e.g., madder, cochineal, lac dye, kermes, viz., reds with tin and aluminum, claret browns with copper and chromium, and dull violets with iron. other dyestuffs, like camwood, brazilwood, and their allies, also young fustic, give always fugitive colors whatever mordant be employed; others again, e.g., weld, old fustic, quercitron bark, flavin, and persian berries, give fast colors with some mordants and fugitive colors with others; compare, for example, the fast olives of the chromium, copper, and iron mordants with the fugitive yellows given by aluminum and tin. a still more striking case is presented by logwood, which gives a fast greenish-black with copper and very fugitive colors with aluminum and tin. other experiments have shown that the chromium and iron logwood blacks hold an intermediate position. abnormal properties are found to be exhibited by camwood and its allies, with aluminum and tin, the colors at first becoming darker, and only afterward fading in the normal manner. when we examine the silk patterns, we find, generally speaking, a similar degree of fastness among the various natural dyes, as with wool; in some instances the colors appear even faster, notice, for example, the catechu brown and the colors given by brazilwood and its allies, with iron mordant. on examining the cotton patterns, we are at once struck with the marked fugitive character of nearly all the natural dyes. the exceptions are: the madder colors, especially when fixed on oil-prepared cotton, as in turkey red; the black produced by logwood, tannin, and iron; and a few mineral colors, e.g., iron buff, manganese brown, chromate of lead orange, etc., and prussian blue. cochineal and its allies, which are such excellent dyes for wool and silk, give only fugitive colors on cotton. the main point which arrests our attention in connection with the natural dyes seems to me to be the comparatively limited number of fast colors. very remarkable is the total absence of any really fast yellow vegetable dye, and it is probably on this account that gold thread was formerly so much introduced into textile fabrics. notice further the decided fastness of prussian blue, especially on wool and silk; while we cannot but remark the comparatively fugitive character of vat indigo blue on cotton, and even on silk, compared with the fastness of the same color when fixed on wool. now, let us turn our attention to the _artificial coloring matters_, derived with few exceptions from coal tar products. here again we have two classes, "mordant dyes" and "direct dyes." both classes are somewhat numerous, but whereas the former may be conveniently shown on a single diagram sheet, it requires a considerable number to display the latter. first let us examine the wool patterns dyed with the "mordant dyes." we find there a few yellow dyes quite equal in fastness to those of natural origin, or even somewhat surpassing them, e.g., two of the alizarin yellows, viz., those marked r and g g w. except in point of fastness and mode of application, i may say that these are not true alizarin colors, neither are they analogous to the natural yellow dyestuffs, for they are incapable of giving dark olives with iron mordants. truer representatives of the natural yellow dyes appear, however, to exist in galloflavin and the alizarin yellows marked a and c, and, as you see, they are of about the same degree of fastness. among the red dyes we have alizarin and its numerous allies, and these are certainly fit representatives of the madder root, which indeed they have almost entirely displaced. the most recent additions to this important class are the various alizarin bordeaux. the only dyes in this group which appear somewhat behind the rest in point of fastness are purpurin and alizarin maroon. on this same diagram we notice, also, fast blues and dark greens, of which we have no similar representatives among the natural coloring matters. i refer to alizarin blue, alizarin cyanin, alizarin indigo, alizarin green, and coerulin. further, an excellent group of coloring matters, giving fast browns and greens with copper and iron mordants respectively, is formed by naphthol green, resorcinol green, gambin, and dioxin. the only fugitive dyes of the class now under consideration are some of the yellows, gallamin blue and gallocyanin. if we now turn to examine the colors given by these artificial "mordant dyes" on silk, we notice, also, a good series of fast colors similar to those which they give on wool; and even on cotton we see many fast colors, of which we have no representatives among the dyewoods. if we were not prepared to find so few really fast natural dyes, surely we cannot but be surprised to find what a considerable number of fast dyes are to be met with among the coal tar coloring matters requiring the aid of mordants. on these diagrams, the first vertical column shows the stain given by the coloring matter alone; the remaining columns show the colors obtained